This PDF file contains the front matter associated with SPIE Proceedings Volume 12080, including the Title Page, Copyright information, and Table of Contents.

Conventional maximum power point tracking algorithms are usually fall into local peak power point under non-uniform solar irradiance. So an improved butterfly optimization algorithm for photovoltaic maximum power point tracking is proposed. In global updating phase, the introduction of previous position change and the rewriting of butterfly position update equation are used to improve convergence speed and search accuracy. In local updating phase, the best position of individual butterfly is introduced to improve search efficiency. The simulation and experimental results show that IBOA can track the maximum power point quickly and accurately, and the tracking speed and the tracking efficiency are better than PSO.

With the development of smart grids, the requirements for online real-time monitoring of transmission lines are gradually increasing. Fiber sensors have both sensing and transmission functions, and are gradually being widely used in the field of online monitoring. Among them, the optimal configuration of the sensor becomes very important. In this paper, an improved artificial fish swarm algorithm is proposed to solve the optimal sensor configuration problem; the optimized configuration of the downhole flat cable structure sensor is simulated and analyzed, and its performance is compared with the particle swarm optimization (PSO) algorithm. The results show that the improved artificial fish school algorithm has obvious advantages in the convergence accuracy and convergence speed of the sensor optimal configuration problem. This method can effectively improve the coverage effect and device utilization, and reduce the cost consumption.

Due to the volatility, randomness and seasonality of the load, there is no effective prediction model for the load development trend after the large-scale "coal to electricity" access to the rural distribution network, which affects the capacity planning of the rural distribution network. Aiming at this problem, this paper deeply analyzes the load characteristics and influencing factors of "coal to electricity" in rural areas, puts forward a screening method of single forecasting model based on grey correlation degree and effectiveness index, establishes the optimal medium and long-term combined forecasting model of "coal to electricity" load, and puts forward the flow chart of forecasting model. Finally, an example based on the historical data of a typical "coal to electricity" area is given to verify the results. The results show that the combined forecasting model can further improve the accuracy of the medium and long-term load forecasting results of "coal to electricity" through dynamic weighted optimization of the combined forecasting results.

The Grey model GM(1,1) is always used in dynamic prediction of grey system. But actually, it is difficult for transmission and distribution loss to grow exactly as GM(1,1), which makes loss of prediction accuracy and limits its application in reality. By combining GM(1,1) with the Markov model, we predict the transmission and distribution loss. The result indicates: the Grey-Markov model can improve the prediction accuracy of transmission and distribution loss.

In order to solve the problem of long execution time of complex dispatching instruction ticket, an automatic generation method of parallel strategy for dispatching instructions in distribution network based on clustering and layering is proposed. Firstly, the associated device cluster model is established. The operating devices in different associated device clusters can be executed in parallel, and the devices in the same associated device cluster can be executed in hierarchical order. Secondly, based on the method of cluster analysis, the device parallel operation cluster adjacency table DPCT is generated. Finally, the parallel strategy generation of scheduling instructions based on layering is proposed, and a detailed calculation formula is given. The example analysis shows that the method described in this paper can significantly improve the efficiency of the rapid execution of complex large-scale scheduling instruction tickets. It can better meet the needs of onsite dispatching operation.

In order to reduce harmonic analysis error caused by spectral leakage and picket-fence effect, the Blackman-Harris window and interpolation algorithm is applied to the harmonic analysis for the voltage and current signals acquired in transformer terminal unit (TTU). The principle of the Blackman-Harris window and interpolation algorithm is introduced, and programs about the algorithm and the fast Fourier transform (FFT) algorithm are written. Voltage signals with different frequencies are numerically generated and the real voltage signal is measured. The FFT algorithm and the Blackman-Harris window and interpolation algorithm are used to conduct harmonic analysis on those signals. The results reveal that the latter can accurately obtain the signal frequency, the amplitude and phase of each harmonic. It can meet the requirements of TTU on harmonic analysis. This work provides a reference for power quality analysis.

To effectively suppress the side lobe level of array antenna and to improve global optimization, an improved cultural genetic algorithm (ICGA) combined with a multi-population parallel algorithm was proposed in this paper. The novel algorithm used better acceptance function, influence function, and update function for the cultural algorithm (CA). Furthermore, instead of single population, a multi-population parallel algorithm was introduced to population space to achieve genetic evolution. This novel algorithm, multi-population cultural genetic algorithm (MPCGA), has stronger ability of globe search, effectively avoids trapping into local optimum, and significantly suppresses the premature convergence. MPCGA was applied to optimizing the phase of array antenna. For comparison, the well-known CA, GA, and ICGA were tested for optimization of the array antenna as well. The simulation results showed that MPCGA successfully achieved a good balance between the ability of global and local search, and higher convergence rate. While GA and ICGA lost their convergence for 100-element array simulations. The convergence curves for all algorithms tested in this work revealed that MPCGA had the best performance in minimize the antenna side lobe levels.

Aiming at the problem that it is difficult to obtain the core parameters of the current transformer simulation model, a genetic simulated annealing algorithm is proposed in this paper. This method combines simulated annealing algorithm with genetic algorithm to overcome the premature phenomenon of traditional genetic algorithm. It realizes the fast fitting of core specific parameters of current transformer J-A model, and can quickly build the current transformer simulation model. The effectiveness of the algorithm is verified by example simulation.

Distribution network planning big data analysis platform is a software used to assist in planning and design. It is used to improve the efficiency of data query, processing, analysis and statistics. The platform has the functions of automatic verification, upload and download of basic data details, automatic summary of planning outline, automatic generation of main index table of city and county distribution network, and visual display of distribution network.Through the vertical penetration of overall analysis, power grid scale, power supply quality, power grid structure, equipment level, power supply capacity and other indicators, the query, statistics and display of detailed data and operation indicators of provincial, municipal and county power grids are achieved.

In view of the position control vibration problem of permanent magnet synchronous motor, the control model of permanent magnet synchronous motor is simulated by using Simulink software. At the same time, according to the structure of the system model, an input shaper is added to the input end of the system to suppress the vibration of the system. However, the input parameters of the shaper are highly dependent on the parameters of the system model, so it is usually necessary to accurately identify the system model. However, the identification of permanent magnet synchronous motor is often not accurate enough, which makes it difficult to determine the input parameters of the shaper. Aiming at the problem that the input shaper is too dependent on the system, a method of input shaper parameter optimization based on genetic algorithm is designed and verified by experiments. The results show that the parameters of the input shaper with better effect can be selected by genetic optimization, and the dependence of the input shaper on the system model is reduced.

In this paper, a novel mechanism is proposed for three-axis attitude adjustment of a satellite. The purpose of the simulation is to analyze flow field of the spherical MHD attitude controller on the flow field distribution, angular momentum, and output torque. According to the numerical results, a combination of pole and slot numbers is proposed for the physical design of MHD-SAC. This study can provide a reference for the optimal design of the attitude adjusting mechanism.

This paper aims to obtain a hybrid algorithm to suppress the common mode voltage (CMV) while suppressing high frequency harmonics for the three-phase voltage source inverters (VSIs). The common mode interference noise caused by CMV and high frequency switching noise caused by PWM control switch on and off will cause electromagnetic interference (EMI) to the system and affect the electromagnetic compatibility of the system. The sources of CMV and high frequency switching noise of VSIs are studied in this paper. This paper proposes a hybrid algorithm which can suppress both CMV and high-frequency noise. The correctness and effectiveness of this method are confirmed by experimental results.

In view of the importance of obtaining the position information of machines and tools in the collection and safety control of incoming and outgoing information of power equipment, a wireless three-dimensional positioning method based on deep reinforcement learning DRL is proposed. Modeling is based on the signal non-line-of-sight(NLOS) propagation model, which will be based on measurement. The process of target location features such as angle (AOD), angle of arrival (AOA) and time of arrival (TOA) is modeled as a Markov decision process and processed within the DRL framework by using the location features of the above targets as input Finally, the repeated training deep Q-network(DQN) algorithm is used for predictive positioning. The simulation results show that the advantages of using DRL in wireless positioning are verified.

Red sandstone is an engineering rock mass with disaster-causing characteristics such as low strength, weak bonding and proneness to softening and disintegration in water, all of which will generate great impacts on the regional engineering construction. A wide range of red-bed cutting slopes are distributed along multiple expressways in southern Anhui. The instability of such slopes will lead to major economic and security loss. Since the rainy season in 2020, Anhui Province suffered wide-range heavy rainfall, where the rainfall reached over 300 mm in some areas of southern Anhui within 24 h, belonging to torrential rainstorm, after which, landslide disaster occurred with a lot of red-bed cutting slopes witnessed along G4012 Expressway in southern Anhui. In this study, a red-bed cutting slope in Jixi segment was taken as the study object, with the main lithology of Huizhou Formation ferrous siltstone. Three rainfall intensities were set by combining the regional rainfall characteristics, the slope stability under different rainfall intensities was calculated via Midas finite element software, and a slope support and reinforcement scheme was designed based on the characteristics of this slope.

The compressive strength prediction model of carbon fiber concrete is first introduced. Based on the limit equilibrium method and Hill-cabbage composite damage criterion, the calculation model of axial compression ultimate load capacity considering the fiber volume rate, GFRP tube thickness and fiber winding angle for GFRP confined carbon fiber concrete short column is proposed. According to the existing literature test results, the rationality of the calculation model is verified which shows the proposed calculation model of axial compression ultimate load capacity for GFRP confined fiber reinforced concrete short columns can satisfy the needs of engineering application very well.

Overhauser magnetometer reaches an ultra-high accuracy benefit from the outputted frequency of free induction decay transversal signal is proportional to the magnetization on measuring the real scalar geomagnetic field. Nevertheless, the magnitude of the accuracy is an important factor that severely affects the validity of geomagnetic field data. Since the real value of the geomagnetic field is unknown, we propose a measurement quality estimation method through analyzing the envelope of the free induction decay transversal signal from the Overhauser magnetometer. The estimation model includes the SNR and the decay slope characteristics of the signal is indicated in an two-digit number changes from 00~99. The results demonstrated that the proposed estimation method can effective performance the reliability of magnetometer measurement data in our experiments.

With the rapid growth of the number of electric vehicles in society, their random charging will have an impact on the power grid. In the 5g era, the real-time and reliability of charging station data acquisition and transmission are significantly improved, and the analysis and application of charging data become particularly critical. This paper first puts forward the 3c3c model of 5g charging station, and then studies the corresponding big data batch and stream analysis technology by combining this model with Flink framework, so as to better serve the business of 5g charging station in the future.

For improving the device accuracy of the laser/fiber optic gyro hybrid inertial navigation system(INS), the static test of the system under different environments is carried out. It is revealed that the output of the fiber optic gyroscope(FOG) is seriously affected by the vibration signal and the error increases sharply when the two-frequency dithered laser gyroscope and FOG work together. Then the wavelet analysis method is used to filter and denoise for output of laser gyroscope and FOG. The data processing results show that this method is not only effective for the output of fiber optic gyroscope affected by jitter, but also suitable for the output of laser gyroscope. The mean output values of the two kinds of gyros are exactly the same before and after filtering. But the variance after filtering can be reduced by more than 96% compared with that before filtering and the noise reduction effect is significant. The feasibility of wavelet filtering is verified.

Strengthening the cost management of power transmission and transformation projects plays an important role in ensuring the income level and development capabilities of power grid companies. In view of the early stage cost management of power transmission and transformation projects, which has a high degree of impact on the economics of the project, this article combines the characteristics of the early stage cost management of power transmission and transformation projects, and based on the basic principles of the fuzzy analytic hierarchy process, constructs the early stage cost management evaluation system of the project. This evaluation system can scientifically evaluate and analyze the current state of project cost management in the early stage of the project, analyze the problems of project cost management in the early stage of the project, and improve the level of project cost management in the early stage of the project.

The permanent magnet synchronous motor (PMSM) has the advantages of high torque and no pollution due to its unique permanent magnet (PM) structure. Compared with other motors, PMSMs have a wider range of application scenarios. However, demagnetization failures will occur during the use of PMSMs. As a result, it is important to investigate the change in the PMSMs internal magnetic field characteristic amount when the demagnetization fault occurs in order to determine if the PMSM is working normally. It provides theoretical support for the PMSM demagnetization fault analysis by analyzing the difference between the health and demagnetization of the PMSM, and then summarizing the difference between the characteristic signal of the PMSM during normal and demagnetization. This work conducts a numerical study on PMSM using the finite element analysis method, simulating the demagnetization model of PMSM by varying the residual magnetic induction strength of PM. Calculate and compare the back electromotive force (Back-EMF) and radial flux density under the conditions of 20%, 40%, and 60% PMSM health and demagnetization, respectively, then apply the Fast Fourier Transform (FFT) to the Back-EMF. The results demonstrate that the degree of demagnetization of a PMSM may be determined by measuring the radial flux density and the harmonic amplitude of the Back-EMF.

Fatigue driving is an important factor leading to traffic accidents, often causing serious consequences. Therefore, real-time detection of driver fatigue is the key to avoid fatigue driving. Aiming at the single detection standard that can easily reduce the accuracy of driver fatigue detection, a neural network method based on the multi-modal fusion of forehead EEG and ocular signals is proposed to fully mine the complementary information of the two signal characteristics, and using SEEDVIG, the public data set of Shanghai Jiao tong University for training. The experimental results show that compared with a single modal. Multi-modal fusion has a better recognition effect for fatigue detection, and its accuracy rate reaches 96.43%, which is helpful to promote the application of the fatigue detection system based on EEG signals in the driving process of the driver.

The fluid momentum ring based on magnetohydrodynamics (MHD) as an actuator for satellite attitude control has advantages in terms of reliability that are not found in conventional flywheel mechanisms. In the design study of the fluid momentum ring based on MHD, the paper presents an optimized design of the magnetic circuit of the fluid ring and a coupled FEM analysis of the multi-physics field of the electric-magnetic-fluid. The proposed design is able to reduce the influence of the induced magnetic field generated by the current on the intrinsic magnetic field and reduce the coupling effect between the electric and magnetic fields. Unlike the general motor structure, the magnetic field in the fluid cavity acts at a greater distance. Here the magnetic circuit is designed purposefully and optimized using particle swarm algorithm. Finally, the designed fluid momentum ring is simulated with FEM to analyze the coupled electric-magnetic-fluid multiphysical field.

When a single-phase ground fault occurs in the distribution network, the current on each line in the system will be different, which can be used as the criterion of fault location. However, because the three-phase load current is much larger than the fault component current, the signal of the fault component of the three-phase current is not obvious, and the location method will fail only by judging by the phase current. This paper proposes an improved fault location method based on the three-phase current of the line: the fault occurrence time is judged by the zero-sequence currents synthesized by the three-phase current. The fault component of the system three-phase current is obtained by subtracting the phase current before and after the fault time by using the detection device installed on the line, Then, the difference between the fault components of each line and the zero-sequence current of the line is used to enhance the difference between the lines, and the signal similarity judgment results are obtained, which makes the fault characteristics of the fault path significantly different from the non-fault path. The fault section location can be determined locally by comparing the overall area between the lines. The paper gives the specific fault location process and criteria and verifies the feasibility of the method through simulation experiments and actual field data.

Convolutional neural network (CNN) has become a key research area in artificial intelligent technology. A case study of garbage identification and classification using convolutional neural network is presented in this paper. The CNN model with five convolutional layers is used to extract feature maps from garbage pictures, and classifies six types of domestic garbage. ZYNQ-7020 is employed to deploy the CNN model in order to take advantage of high efficiency, low power consumption and flexibility of FPGA platform. Additionally, the classification results are obtained at the FPGA terminal by running Python code through PYNQ. The study demonstrates an efficient approach to practically deploy CNN model and implement image classification on FPGA platform.

As a new type of water operation platform in recent years, surface unmanned boats have gradually become a hotspot for many scholars to study. The path planning capability of unmanned boat is an important measure of the intelligence degree of unmanned boat. To address the obstacle avoidance problem of surface autonomous unmanned boat path planning, this paper proposes a global path planning method for surface autonomous unmanned boats based on the improved grid method by modeling the known water environment with a grid method. In order to accurately simulate the impact of obstacles on the path planning of surface autonomous unmanned boats due to the drifting effect, this paper simulates the drifting increment of obstacles on the water surface by setting different obstacle forms and sizes, and conducts a MATLAB simulation platform to simulate the drifting increment of obstacles on the water surface. The simulation experiments prove the real reliability of the improved obstacle avoidance strategy algorithm proposed in the main paper.

To alleviate the spread of the epidemic, most public places have begun to limit the number of trips. Therefore, this article proposes a pedestrian counting scheme based on YOLOv5 and DeepSORT for multi-target detection and tracking. Using the network weights trained by the coco data set and combining the YOLOv5 detector and the DeepSORT tracker, the pedestrians are detected and tracked, and the number of people entering and leaving is calculated, thereby realizing the control of the number of floating people. Through experiments on streets and subway stations, it is proved that this algorithm is suitable for tracking and counting high-density people, and based on ensuring the real-time performance of the system, it provides high system accuracy and robustness.

Aiming at the application requirements of 100-meter-level laser wireless power transmission, a 100-meter-level laser wireless power transmission system is designed by adopting the method of system optimization design. The laser emitting device is designed with a fiber laser with adjustable power of 50W-150W, and the wavelength of the emitted laser is 910nm; Designed a photovoltaic cell array using monocrystalline silicon photovoltaic cells; Furthermore, a 150W 100-meter laser wireless power transmission experimental system was constructed, and power transmission experimental research was carried out. Experimental results show that the laser power transmission system achieves the expected goal of 15% power transmission efficiency, and can be widely used in the field of laser wireless power transmission, such as the charging of UAVs.

This paper presents a control method for a single-phase differential Buck inverter without virtual quadrature based on dq coordinate transformation is proposed. This method converts the output of the two-phase bridge arm of the single-phase differential buck circuit to the dq frame for control, and can omit the one-phase virtual quadrature quantity additionally constructed in the traditional dq frame. For the two-phase capacitance imbalance problem in the control system, the symmetrical component method is used and then the corresponding phase sequence is transformed and controlled. Finally, the simulation proves that the proposed method can effectively realize the zero steady-state error control of the output voltage.

With the continuous promotion of industrial transformation and upgrading in China, the demand for servo system is growing, and in some specific occasions, such as industrial sewing machine, SMT machine and so on, fast and accurate position control is needed. The traditional three - closed - loop control system has been unable to meet its control requirements. This paper presents a position control and speed regulation method based on voltage vector amplitude and Angle adjustment. This method optimizes the PI regulator parameters and adds a fine-tuning process under the traditional three closed loop control system. After the hardware system and software system are completed, the experimental platform is set up to verify the actual hardware function and the feasibility of the control algorithm. And the speed and position feedback of the motor are printed through the serial port to detect and verify the position control. Compared with the traditional method, the experimental results show that the proposed method can effectively shield the overshoot generated by the three closed-loop system and can quickly position the rotor of the motor, thus achieving "fast", "accurate" and "stable" rotor position positioning.

As China’s basic industry, with the continuous development of China’s social economy and technology, agriculture is gradually developing in the direction of intelligence. Through the application of the Internet of Things (IOT) technology, agriculture is undergoing large-scale, intensive and high-quality construction, and gradually enters the high-tech innovation development mode. In this study, by exploring the IOT technology application in “smart agriculture”, the future development model of IOT technology is analyzed, which will help promote the innovation of modern agricultural technology, thereby increasing productivity and efficiency.

There are many factors affecting the consistency of power battery. Aiming at the problems of poor consistency and inaccurate clustering reorganization of retired power batteries, this paper mainly considers three characteristic parameters: capacity, voltage and internal resistance, and proposes a clustering reorganization method of retired power batteries based on machine learning. Firstly, the article based on the characteristic parameters of retired batteries, analysed its health status and service life and through machine learning, according to the actual requirements of groups, clustered and reorganized the batteries and its accuracy is analysed; Then the article analysed the applicability of power battery echelon utilization scenario.

To solve the problem of high alarm error rate caused by unbalanced load distribution in power failure state of distribution network, a real-time online automatic warning method for power failure status of distribution network is proposed. The topology structure of distribution network is established, and the connection relationship of power equipment is represented by binary form, the shortest distance of nodes is calculated and the power supply path is searched in real time. By determining the objective function and constraint conditions, the power flow calculation model of distribution network is constructed to ensure the economic performance of power supply path. The category of feature vector of fault factors is determined, the outage time length trained according to decision rules is obtained, and the power failure state warning model is established according to the correlation matrix. The experimental results show that the false alarm rate of this method is lower than that based on LightGBM model and Gray Markov model in the outage failure of weather, operation and equipment, which can improve the level of automatic operation and maintenance of distribution network.

In the process of running high temperature superconducting (HTS) maglev train，the alternating current (AC) loss of superconducting coils is directly related to its safety and operating cost. In this paper, based on the finite element software COMSOL Multiphysics and AC loss experiment platform of HTS, combined with the actual current of the coils of maglev train which can be thought as superimposing a dynamically adjusted AC component on a steady-state direct current (DC) component, we simulated and measured the AC losses of Yttrium Barium Copper Oxide (YBCO) tape and coils in fact. Measurement data and simulation data are basically consistent with each other. The results shows that AC loss was not positively correlated with the given DC steady-state current. And it is demonstrated that AC loss had some local extreme points for tapes and coils. If we could decrease AC loss by avoiding the extreme points, we would greatly reduce the energy consumption and the material cost of HTS maglev train.

The seven channel road Rzeppa constant velocity universal joint is a new type of transmission bearing with spherical connection. According to the analysis of the stress model of the steel ball in the joint, it can be seen that the different structure of the channel will have an impact on its movement process. Besides the radius of the steel ball, the parameter determining the channel shape is the change of eccentricity. Different combinations of long and short axes can be obtained by choosing different eccentricity for elliptical channel. By setting different combinations of long and short half axes, combined with computer three-dimensional modeling, Adams is imported to analyze the peripheral force and normal force on the steel ball. The results show that the change of eccentricity can effectively affect the peripheral force and normal force on the steel ball.

Aiming at the problems of a large-scale power failure and the slow recovery of the system which caused by converter block in the case of inter-pole short circuit in DC distribution network, this paper proposes a short-circuit protection scheme of inter-pole short circuit in DC distribution network based on fault current limiting module and DC circuit breaker (DCCB). Based on resistive current limiting topology by analyzing the bridge arm current of the converter and the transient characteristics of the DC side fault current, and combining the performance parameters of the converter IGBT, diode devices, and DCCB, we give the theoretical calculation method and selection principle of the resistance parameters. The proposed protection scheme can realize the fault ride-through of the converter during the DC inter-pole short circuit, which reduces the outage scope, lower the requirements of DCCB operation time and opening capacity, and shorten the system recovery time. Simulation results in the PSCAD/EMTDC environment combined with actual engineering parameters verify the correctness and feasibility of the protection scheme.

In the process of SLAM (Simultaneous Localization And Mapping), an essential link is data association. Data association provides the basis for state estimation to ensure that the robot can make full use of the obtained environmental information to realize positioning and mapping. Aiming at the problems of low association accuracy of current single target data association algorithm and difficult calculation of multi-target data association algorithm, a bat optimized multi-target data association algorithm based on joint maximum likelihood is proposed to ensure accurate data association processing results, and reduce the computational complexity of SLAM algorithm. It is based on joint maximum likelihood, The multi-objective data association problem is transformed into an optimization problem to solve the optimal combination, and the bat optimization algorithm is used to search the optimal data association. The slam process of the mobile robot experiments show that the proposed bat optimized data association algorithm improves the rapidity and accuracy of slam process of mobile robot.

The Hanning window and interpolation algorithm is used to the frequency estimation for voltage and current signals acquired in transformer terminal unit (TTU), and the algorithm is validated by the frequency estimation for actual voltage signals. On this basis, the influence of signal frequency, harmonic, signal-to-noise ratio (SNR), sampling duration, sampling frequency and quantization of analog digital converter (ADC) on the accuracy of frequency estimation is investigated based on the numerically generated voltage signal. The results reveal that the error is proportional to the difference between the actual signal frequency and the rated value (50 Hz). When the total harmonic distortion (THD) varies in the range of 0~10%, the error is almost independent of THD. The error decreases with SNR, and the rate of decrease reduces with SNR. The sampling frequency has little effect on the error when the sampling duration is kept constant. When the quantization bit varies from 4 to 16, it has little effect on the error. Suggestions on the selection of sampling parameters for TTU frequency analysis using the Hanning window and interpolation algorithm are also given.

With the continuous development of power system, the scale of power data has increased greatly compared with before. Traditional data processing methods are difficult to meet today's needs. Since the emergence of knowledge graph, it has very significant advantages in data storage and processing, and has been used in many other fields. However, at present, the application of knowledge graph in power field is still few. Therefore, This paper discusses the possible application direction of knowledge graph in power system. For example, the question answering system based on knowledge graph can greatly improve the search efficiency and reply effect. The power grid auxiliary decision system based on knowledge graph can provide decision-making process for reference and enhance the reliability of decision while providing results.

The investment in power grid projects especially distribution network projects is increasing due to continuous growth of the national economy. To implement the designed goals of carbon peaking and carbon neutralization, the investment of power grid companies in the future will inevitably follow the concept of carpet investment. Therefore, this paper comprehensively depicts the benefits of distribution network projects and the requirements of carbon peaking and carbon neutralization. An evaluation index system of investment benefits of distribution network projects is established, and the standard score and index weight for each index are determined. It is expected that the presented method could support power grid companies to better implement investment optimization of distribution network projects.

With the rapid development of the new generation of information technology, the foundation and core role of software are becoming more and more prominent, with more and more applications and complex functions, larger and larger code scale, more and more software quality problems, and more and more software quality data are generated in the software life cycle. In today's big data era, through the effective collection, management and application of these software quality data, the utilization of software quality data can be effectively improved, so as to improve software quality. Based on this, this paper studies the whole life cycle quality data of software, including fault data for software quality improvement, process data for software quality risk prevention and evaluation data for software quality evaluation, for the concept, development, testing, use and maintenance, decommissioning stages of software life cycle. At the same time, this paper studies the requirements definition, collection, transmission, processing, storage, application and sharing of software quality data lifecycle management methods. This can support the construction of software quality data resources, provide decision-making basis for software quality management activities, and help to improve software quality.

Typhoon weather will cause great damage to the transmission line, such as tower falling, line breaking, wind deviation tripping, etc. The research on the response of tower and conductor under wind field is an important topic in today's power grid. In order to study the stability of tower line system in windy weather, this paper models the typical tower line, simulates the tower line model by using the finite element method, and obtains its mechanical response in the wind field; Comprehensively consider the factors that may lead to tower damage under the wind field, and analyze the degree of tower damage and the correlation between various parameters, so as to provide a reference basis for the early warning and transformation of the power department.

Rock tortuosity is an important parameter to measure the curvature of fluid seepage path in porous media. At present, the calculation model of rock tortuosity (original model) is mainly derived based on the equal diameter capillary bundle model and the principle of equivalent seepage. Because the influence of pore throat heterogeneity is not considered, the calculation result is quite different from the real rock. For this reason, this research focuses on the influence of pore throat heterogeneity, and uses rock multi-scale pore-throat distribution and composition information to establish a new rock tortuosity calculation model (new model). Taking the X oilfield in the Ordos Basin of China as an example, the rock tortuosity calculation was carried out. The results show that the calculated rock tortuosity of the new model is higher than that of the original model, with a relative error of 25.4%, indicating that the heterogeneity of pore throats has an important influence on rock tortuosity. Because the original model underestimated the tortuosity of the rock, the actual seepage path of the fluid particle in the pore throat may be more tortuous than previously known.

At present, most of my country's 110kV transmission line planning passes through mountainous areas, and the threat of landslides to transmission towers cannot be ignored. This article describes the typical characteristics of landslides, and extracts the causes of landslides based on them. Based on the analytic hierarchy process, the weight of each cause to the formation of the landslide is studied, and the stability evaluation model of the tower foundation landslide is constructed based on this. Through the analysis of the results, the principle of site selection for the foundation of transmission poles can be put forward.

In order to study the behavioral characteristics and evacuation efficiency of the relative flow movement of pedestrians on stairs under two evacuation modes: queuing evacuation and random evacuation, a simulation study of stair evacuation based on Massmotion software was carried out. The simulation results show that compared with random evacuation, the speed of queuing for evacuation is greater, the density of people is smaller, the crowding time during the evacuation process is longer, and the evacuation efficiency is higher; as the number of evacuated persons and the width of the stairs increase, the queuing evacuation is relatively higher. The evacuation time for random evacuation is shorter. The research data can provide a certain reference for building staircase design and staircase evacuation guidance.

In order to improve the atomization effect of the snowmaker, the numerical simulation method was used to study the influence of the structure parameters of the snowmaker, including the mixing chamber length and inlet diameter ratio, on the atomization effect of the snowmaker, and the influence of the gas-liquid relative velocity on the atomization particle size distribution was briefly analysed. The results show that different structural parameters directly affect the average diameter of the droplet. In order to ensure the atomization effect, the suitable length of the mixing chamber is 18 ~ 24 mm, and the angle between the inlet and the average diameter of the droplet is positively correlated, which provides a reference for optimizing the structural parameters of the snow crystal sprayer.

Multi-station integration is an important foundation for the construction of power Internet of Things and an important support for achieving low-carbon development. The variety of modes of integration is discussed, and an in-depth analysis of the whole-site monitoring technology under multi-station integration scenarios, including data characteristic analysis, system architecture design, information model, edge computing processing, and main plant service application. The construction of the pilot project is presented, it can provide guidance and reference for the unified monitoring of the whole station under the multi-station integration of the whole station, promote the in-depth promotion and application of multi-station integration, and provide strong support for the development and construction of the power Internet of Things.

Flue gas condenser can solve subsequent environmental problems caused by wet desulfurization. In order to realize the numerical prediction of the removal of SO₂ and NO in flue gas condenser, based on the vapor-liquid equilibrium and chemical absorption equilibrium of condensate and solute gas, the relationship between the chemical equilibrium constants and the mole fraction of SO₂ and NO was determined. The process including flow, heat transfer, condensation of steam and absorption of SO₂ and NO by condensate in the flue gas condenser was simulated by numerical method. The results showed that: under one certain operating condition, the condensation efficiency of steam was 16%, the removal rate of SO₂ was 12.14%, and the removal rate of NO was 9.2%. The numerical simulation results showed good agree with the operation measurement data.

Based on a mechanical connection channel project in Hangzhou, Aiming at the settlement problem of tunnel structure in the jacking process, the characteristics of connection channel structure design and mechanical construction are analyzed, and the elastic foundation beam theory is introduced. The initial end fixed cantilever multi-section foundation beam model is established, and the parameter sensitivity analysis and engineering case analysis are carried out. The results show that the end settlement increases with the increase of bending spring stiffness coefficient of tunnel structure, and the end settlement is hyperbolically related to the logarithmic stiffness coefficient. The subgrade coefficient and the end settlement showed a linear decreasing relationship; the end settlement increases with the increase of initial rotation angle; the endfixed multi-section foundation beam model has certain reliability in simulating the influence of grouting on the settlement deformation control of subway tie passage.

The high-filled subgrade can be compacted by dynamic compaction and the lateral deformation can be limited effectively by reinforced soil, both methods can strengthen the stability of subgrade, but they will restrict each other when the two methods are used in the same project. It shows that reinforced soil can limit the function of dynamic compaction, on the contrary, the broad dynamic compaction energy can easily lead to fracture failure of reinforced plastic materials. To solve the problem of how to balance and optimize the parameters of dynamic compaction and reinforcement, the paper studied it combined model experiment. According to change the embedding depth of reinforced materials, the conclusions are drawn that the ratio of the effective reinforcement depth and the crater depth is exponential grows relationship with the embedment ratio, it is concluded that the single factor calculation formula for estimating the effective reinforced depth.

The construction of China's electricity market has been continuously promoted since 2015. With new type of market entities emerging on the low-voltage distribution network such as distributed generators, load aggregators, and microgrids, the decentralized electricity markets are also growing besides the development of main grid electricity market. Considering the decentralized market is not easy to be self-balanced and the demand and supply requirement of the entities is difficult to predict and plan, it is necessary to dispose the imbalance electric quantity with the main grid market. This paper proposes a coordination mechanism between the main grid market and the decentralized market, which realizes the imbalance of purchase and sales demand from the decentralized market at different time scales.

A new type damping system, parallel cantilever-toggle viscous system (P-CTV), is proposed in order to improve seismic energy dissipation efficiency of the viscous dampers in viscous damping outriggers in super high-rise building. The working mechanism and construction characteristics of the system are introduced. ETABS finite element program is used to analyze nonlinear time history response of a typical 276.5m engineering example, and the damping control effect of the P-CTV in super high-rise building under design earthquake is studied. The results show that the deformation of P-CTV system is completely unrelated to the deformation of the floor by adopting the floor beam offset and floor opening, the construction is simple and has little impact on structure quality. The P-CTV has a good damping control effect on super high-rise structure, 12 sets of P-CTV could realize the damping rate of story drift and story shear up to more than 21% under the action of design earthquake. The P-CTV could make the viscous damper have good deformation amplification efficiency, the nominal displacement amplification factor of viscous damper could reach 4.77~6.25, and the damping ratio of the damper could reach 51%.

This paper proposes a novel rotor flux observer design method for field-oriented control (FOC) system of the induction motor (IM). To improve the observation accuracy and the robustness to the parameter variations, the full-order terminal sliding-mode (FOTSM) is utilized in the rotor flux observer design. The stability and fast convergence of the rotor flux estimation is guaranteed. The integral-type control law reduces the chattering and ensures the output injection of the observer smooth. The simulations and experiments show the effectiveness of proposed observer design method.

The electrical characteristics of power modules often involve parasitic parameters, and the parasitic inductance mainly depends on the metal bonding wire. The length, diameter, material, shape, and connection method of the bonding wire will affect the electrical characteristics of the power module. The parasitic capacitance mainly depends on the DBC ceramic layer. Through module division and dimensionality reduction, the effect of the width and height of the DBC on the parasitic capacitance in the planar state is briefly analyzed, which lays the foundation for the subsequent analysis of the 3D model. Parasitic inductance and parasitic capacitance together affect the size of the corner frequency in electromagnetic interference. Change the position of the upper and lower bridge arms through stacked commutation, reduce the commutation path voltage, reduce the parasitic inductance, and suppress the voltage overshoot and voltage oscillation caused by the larger current rate of change.

With the rapid development of UHV projects in power grid, partial discharge fault has become one of the main faults of power equipment, most of which are GIS faults, but there is a lack of research on the propagation of partial discharge UHF electromagnetic wave signal in GIS. Based on this, this paper analyzes the propagation principle of UHF electromagnetic wave propagation in GIS, draws a simplified GIS model, and studies the characteristics of TEM, TE and TM waves by analyzing the size and distribution characteristics of various types of field strength in GIS; At the same time, by building GIS simulation model, the distribution characteristics of radial electromagnetic wave are deeply studied. It is found that the high-order mode component of electromagnetic wave decays rapidly due to the reflection and leakage of insulator when passing through the first insulator, and the electromagnetic wave signal is mainly TEM mode component. When partial discharge electromagnetic wave leaks through insulator, The frequency components below 1250mhz have obvious attenuation, and the frequency points with concentrated electromagnetic wave energy have "upward shift". This research can provide a strong theoretical basis for GIS partial discharge detection.

SiC MOSFET is a kind of promising power device for transportation electrification. In electrified vehicles, SiC inverters show strong competitiveness for its high efficiency and power density, especially for high-performance applications. A SiC power module generally consists of multiple MOSFET dies and Diode dies. Junction temperature estimation of different dies in different operation points is a critical problem for practical applications. In this article, power loss of SiC devices in a motor inverter is analysed and calculated in the time scale of switching period. Subsequently, a junction temperature estimation method combining 1D foster thermal model and 3D FEM thermal model is proposed. The maximum junction temperature in a SiC power module can be estimated with low computational burden. Working boundary with varying sine current amplitude and switching frequency can also be obtained for real-time control of motor inverters. The effectiveness and practicability of the proposed method is verified with transition simulation.

Single-phase inverters have inherent double frequency problems, which are likely to cause system instability. In this paper, it does not add additional switching devices while retaining the four switching devices of the H-bridge. This topology only needs to split the original filter capacitor on the AC side into two symmetrical connections and can cancel additional DC side support capacitors. For this topology, the fundamental frequency common-mode voltage injection is used to avoid additional low-frequency harmonics derived from the DC side. Theoretical analysis and experiment explain the working principle of the topology. The result proves that this topology can effectively buffer the double frequency of the system without additional switching devices.

A highly protective 400 KW three-phase synchronous generator has been studied for power supplied used in severe environments, such as rail grinding, cement plants and chemical plants. The parameters of the electromagnetic system of the generator were figured out and analyzed with the combination of traditional theory and computer simulation; the structures and insulation levels of its stator, rotor and winding were determined; an efficient heat dissipation system with self-circulating air cooling was designed; a new metal laminated coupling featured by high vibration resistance, easy maintenance and good adaptability to conditions was adopted. In addition, a type test was performed, and it verified the feasibility of the design scheme.

Aiming at the large-scale photovoltaic water pump water supply system, the use of single high-power or multi-unit independent low-power photovoltaic water pumps cannot make full use of solar energy to improve the efficiency of the system. This paper proposes an optimal switching based on power/frequency, so that three photovoltaic water pumps of the same model can be switched under different input power to maximize the utilization rate. Multi-machine scheduling is realized, and the utilization rate of the photovoltaic water pump group is improved.

This paper analyzes the problems existing in current electronic technology teaching and experimental training. On this basis, the application of Multisim circuit simulation teaching in circuit design course is discussed.In practical work, circuit function debugging is regarded as the most important link in electronic circuit design, and it is also the key link to make up for traditional electronic design teaching and experimental debugging.This paper briefly analyzes the application of ProteLJs simulation software in electronic circuit design, promoting the level of ProteLJs simulation software in the application of electronic circuit design.At the same time, the innovative application and skills of Multisim simulation software in power supply design are introduced, which is of great help to circuit design.

This paper introduces a transformer terminal unit (TTU) signal acquisition system based on field programmable gate array (FPGA). The TTU signal acquisition system is realized based on demo board of FPGA (model EP4CE10F17C8), and the corresponding chips and schematic diagrams are also introduced. On the basis of the hardware module, the signal acquisition and display program is written in Verilog HDL language. A signal generator is used to generate voltage signals with different waveforms to simulate the signals acquired by the TTU. Based on the signal acquisition system, these voltage signals are acquired and displayed. The harmonics of the acquired signals are analyzed by fast Fourier transform (FFT). The results of the developed system are consistent with those by the oscilloscope. This work verifies the applicability of FPGA in TTU, and also provides a reference for the implementation of high-performance TTU.

This article proposes a variable-leakage-flux flux-intensifying permanent magnet machine (VLF-FIPMM). Through the addition of magnetic bridge and the innovative design of magnetic barrier, the machine owns the feature of Ld<Lq and variable-leakage-flux characteristic, which not only widens the speed, but also reduces the irreversible demagnetization risk and core loss. Firstly, the design idea and operating theory of the VLF-FIPMM are analyzed. At the same time, a multi-objective genetic algorithm based on sensitivity analysis is introduced to obtain the optimal torque, torque ripple and reverse saliency ratio. Then the overall performance of the VLF-FIPMM is compared with the conventional IPM machine. Finally, the stress and deformation of the VLF-FIPMM are simulated at high speed. The above simulation results also validate the reliability of the design method and optimization.

Resolvers exhibit relatively impressive ruggedness, high accuracy, strong anti-interference ability and wonderful reliability in many household and industrial applications. However, it is necessary to use Resolver-to-Digital Conversion (RDC) to get the position and speed from the resolvers, due to the analogue output of resolvers. In this paper, an RDC system with excellent performance is proposed based on frequency shifting method by using Butterworth low pass filter and type-II Angle Tracking Observer (ATO) to estimate resolver shaft angle. Because of the outstanding frequency response characteristic of Butterworth filter, lower phase delay, more sufficient bandwidth and higher accuracy can be achieve compared by traditional RC filters. Eventually, both simulations and experimental results validate the effectiveness and feasibility of the proposed method.

According to the islanding operation mode structure of photovoltaic-hybrid DC microgrid, this paper proposes a photovoltaic-hybrid DC microgrid energy distribution control strategy to solve the current problems of insufficient battery output and slow short-term high-power tracking. The instantaneous response capability of the energy storage system is improved, the battery capacity configuration is reduced, and the battery life is extended.The DC microgrid operation modes are listed in the form of digital coding, and the switching design of each operation mode is carried out, so as to realize the optimal dispatch of each power supply unit.

The motor drive of the photovoltaic water-pump will have a constant power load (cpl) characteristic in the closed loop system, which leads to a negative admittance effect. The interaction between LC resonance and negative admittance will affect the stability of the entire drive system. This paper establishes the LC input impedance model and the impedance model of the motor drive system, analyzes the instability of the LC input impedance and the negative impedance of the system, establishes a small signal model, and proposes an active damping feedforward method. The stability control method reshapes the input admittance, eliminates the instability of the input admittance, and suppresses the fluctuation of the DC bus voltage. The method's efficiency is confirmed by the simulation results.

As the most important source of carbon emissions, the power industry has huge potential for carbon emission reduction.Based on the traditional dispatching model, this paper comprehensively considers power generation-side resources and low-carbon demand side resources, such as demand response(DR), electric vehicle(EV) and distributed generation(DG), to coordinate dispatching. Simultaneously carbon capture equipment is introduced to establish carbon capture unit which participates dispatching in power system.Basd on above, the cost of carbon trading is introduced into the low-carbon economic dispatching goals. And the low-carbon economic dispatching model including demand side low-carbon resources and carbon capture equipment is established under the carbon trading environment. A simulation example is used to analyze the impact of the introduction of demand side low-carbon resources and carbon capture equipment on the economic and low-carbon benefits of the power system. The results of the simulation example have verified the feasibility and superiority of the proposed model.

Aiming at the problems of inaccurate wind turbine model, limited simulation scale, long simulation time, and low efficiency in the process of wind farm grid connection simulation, a HYPERSIM-RTLAB co-simulation method and interface delay compensation method are proposed. In the proposed method, the power grid model is built by HYPERSIM software, which can carry out real-time simulation of power grid electromagnetic transient. At the same time, the digital-analog hybrid simulation model of wind farm with wind turbine controller is built through RTLAB. which solves the problem of inaccurate simulation of general model. The transmission interface delay between platforms is quantitatively studied, and a co-simulation decoupling method with delay compensation is proposed to complete the joint electromagnetic transient simulation of wind farms connected to the power grid. Finally, the effectiveness and accuracy of the decoupling method is verified by comparison with the distributed line model, and the fault analysis of the wind power grid-connected co-simulation is carried out. The simulation results show that the co-simulation platform can accurately and effectively reflect the real characteristics of wind power grid-connected.

Nine eccentric compression numerical models of GFRP confined reinforced concrete long columns with different eccentric distances were established using finite element analysis software ABAQUS. The influence of eccentric distance on eccentric compression performance of GFRP confined reinforced concrete long columns was investigated based on finite element simulation results. The results show that the increase of the eccentric distance significantly reduces the bending stiffness of the column. The load-midspan deflection curve shows an obvious decline section when load application point is located inside the upper surface of the column. The location of the load application point has a significant influence on the ultimate bearing capacity under eccentric compression of the long column. The ultimate bearing capacity decreases greatly with the increase of eccentric distance, especially when the loading position is gradually eccentric from the axial position to the edge of the column.

Regarding the difficulties in the manual calculation of the generator heating dissipation system of diesel generators, the physical and mathematical models for the finite element analysis of the generators are built, which is illustrated with a marine axial ventilation hydro cooling. The fluid simulation package of Flow Simulation is adopted to analyze the axial ventilation system of the motor, from which the distribution and major parameters of the heating dissipation flow field of the motor are obtained, under normal working conditions. According to the distribution of the flow field, it is found that the new laminated coupling cannot block the heating dissipation of the motor, but can optimize the conventional heat dissipation air duct.

The valve side outlet device is like the ‘neck’ of the converter transformer. It is located at the position where the electric field and current of the converter transformer are most concentrated. The size deviation control requirements are strict. It also needs to consider the coordination with the electric field at the tail of the bushing. It has many insulation interfaces, diverse materials, complex dielectric characteristics and great design difficulty. In this study, multi index optimization design is carried out for the insulation structure of valve side outlet device of converter transformer, and the optimal design scheme is proposed. The research results are applied to engineering products and verified by insulation margin test.

In order to reduce the air-gap eccentricity of the horizontal motor caused by rotor gravity, a new stator core is designed and studied in this paper. The 90° area at the top of the stator core has different stator slots and coil turns from other areas. When the motor is running, an unbalanced electromagnetic force opposite to the gravity is generated in the 90° area at the top of the rotor component, so as to offset the rotor gravity to a certain extent and reduce or even eliminate the air-gap eccentricity of the motor caused by the rotor gravity. The feasibility of the design is verified by electromagnetic simulation.

Compared with the traditional switched reluctance motor (SRM), the permanent magnet assisted reluctance motor (PMa-RM) has higher power density and efficiency, and larger torque ampere-ratio, but also it has larger radial force and torque ripple, resulting in greater vibration, which limits its application in more fields. Firstly, the principle of the PMa-RM to suppress the radial force and torque ripple is analysed in this paper; Secondly, a rectangular slot is set at the top of the rotor of the initial model, and the depth and width of the slot are analysed to obtain the optimized size of slot. Thirdly, a pole shoe is added to one side of the rotor, and the angle and height of the pole shoe are analysed to obtain the optimized size of the pole shoe. Finally, the proposed model with a slot at the top of rotor and a pole shoe at one side of rotor is simulated. The simulation results show that the torque ripple of the proposed model is reduced by 13.35% when the average torque is reduced by 26.22%, compared with the initial model. The radial force peak of the three-phase windings of the proposed model decreases by 25.61%, 21.34% and 27.56%, respectively, at the moment when the winding is turned off.

Controllable reactors are widely used in power systems, analog filtering and automatic devices. Under the condition of strong magnetic bias, the phenomenon of magnetic leakage will cause great difficulties in the precise design of the controllable reactor. It is particularly important to analyze the correlation between saturation phenomena and current harmonics, on this basis, to analyze the magnetic circuit loss, the relationship between magnetic circuit saturation and magnetic leakage, and equivalent magnetic resistance. This article reviews the traditional JA hysteresis model and DC bias, and finds some problems in the current research. Finally, the effect of magnetic leakage and magnetic circuit saturation in the magnetic circuit model was proposed, and then to strengthen the global convergence ability of the iterative operation according to the Ohm's law constraints of the circuit and the magnetic circuit, so as to further improve the accuracy and efficiency of the model and improve the efficiency of stability control, analog filter design, reactive compensation, energy transmission efficiency estimation in the power system.

Single-phase inverters have a wide range of applications in many fields, but there are inherent double frequency problems, and double frequency fluctuations can easily cause system instability. This paper proposes a mid-point common-mode injection power decoupling circuit. The advantage of this topology is that there are no additional switching devices and only the original DC side support capacitors and filter capacitors of the H-bridge inverter can be used to buffer the double frequency power. Simulation and experimental results prove that the method can effectively suppress the secondary ripple on the DC side.

This paper proposes a rule-based energy management strategy of a series-parallel driving system adoped in plug-in hybrid electric vehicles. For the complexity of hybrid system configuration, the coordination controller is optimized based on the overall fuel economy of multiple working modes by means of genetic algorithms. The simulation result shows that the engine operating points are mostly in the high-efficiency area, mode division and power allocation meet the design requirements. The rule-based control strategy designed in this paper is reasonable and effective.

This paper proposes an active capacitor research method based on difference frequency reactive power theory, which realizes low-frequency power output based on high-frequency input and reduces the volume of passive components at the same time. First, analyze the characteristics of difference frequency reactive power theory, and use the single-phase H-bridge vector modulation strategy to analyze based on the series resonant impedance network. Based on the difference frequency theory, an active capacitance control under a synchronous rotating coordinate system is proposed. Finally, the theory is verified by simulation.

Promoting new energy vehicles (NEVs) is considered to be one of the most effective ways to solve the increasingly serious problems of energy security and environmental pollution. With the growing energy shortage and the worsening of environmental pollution, electric vehicle (EV), as a new energy vehicle driven by electric energy, has attracted more and more attention. Because of its small size, high efficiency, large overload capacity and fast response, the brushless electric motor has occupied an important position in the servo field and is an ideal choice for electric drive systems of electric vehicles. The control precision of PMSM depends on the precision of rotor position detection to a great extent. The traditional method of obtaining rotor position is realized by high resolution position sensors, such as resolver, photoelectric encoder. It can obtain the rotor flux position with high resolution accurately and in real time, but this method has high cost. In order to reduce the cost of rotor position detection, the sensorless control technology has been developed. The rotor position is estimated by detecting the variables such as current, voltage and motor parameters. However, the Control Algorithm is complex and requires high parameters, and it doesn't work at full speed. Computationally efficient design of interior permanent magnet (IPM) motor rotor features is investigated utilizing analytical methods. The rotating transformer and the high-frequency signal method independently detect the rotor position, the high-frequency signal method verifies the detection precision of the rotating transformer at low speed, and the high-frequency signal method rotor position detection system at high speed stops working, in the case of a rotating transformer fault, the high frequency signal method system supports the motor to drive at low speed in fault mode.

In this paper, two new variable leakage flux permanent magnet motors with different structures are proposed. The leakage flux of the two motors can be adjusted automatically with the change of q-axis current, and the operation principle of the two motors is analyzed by using equivalent magnetic circuit analysis model. Furthermore, the two motors owe the characteristic of Ld<Lq through the special design of rotor structures to enhance the flux-weakening capacity. The finite element method is used to analyze the electromagnetic characteristics, temperature characteristics and mechanical characteristics of the two motors in detail. The results verify the characteristics of Ld<Lq and the controllable leakage flux of the two motors, and also verify that the motor with multi-stage permanent magnets has a wider speed regulation range, a larger output torque, lower temperature rise and better robustness than the motor with single-stage permanent magnets.

Steel coil winding film packaging is an important part of steel coil packaging, but the current packaging method is mainly manual operation, which has the disadvantages of poor packaging quality and low packaging efficiency. Based on the analysis of packaging technology and packaging process, this paper designs the large steel coil through core winding packaging machine, and completes the mechanical structure design and three-dimensional modeling. This machine includes fixed frame, moving beam system, lifting beam system, C-shaped track system and through winding trolley system. In addition, this paper completes the finite element analysis of key parts and the modal analysis of the whole machine, and obtains the low-order natural frequency and vibration mode of the whole machine. The analysis results show that the material selection of key parts is reasonable, and the ultimate stress under working state meets the actual performance requirements.

With the development of the implantable neural recording system, how to power the device has already became an significant problem. Researchers have come up with several methods such as utilizing battery. However, these two early methods both have weakness which limit the further development of the implantable medical device (IMD). Thus, new methods emerge to solve these problems, which serve as ideal substitute for the battery, including the radio frequency (RF) radiation, inductive power transfer (IPT) and acoustic power transfer (APT). This paper mainly focuses on these three methods and discusses their advantages and the disadvantages.

Aiming at the time-consuming and labor-consuming problem of manually checking the 10kV feeders and transformers relationship in distribution network, this paper proposes a checking method of feeder-transformers relationship based on the characteristic representation of the voltage time series. Firstly, the voltage data is cleaned and preprocessed to obtain the compliant voltage data set and calculation three-phase voltage of ABC into a single-phase voltage. Then, for each transformer, the voltage time data are divided into several sub series of the same length. Each time point of the voltage time subseries is extended to feature vectors containing global and local characteristics. Then calculate the characteristic covariance matrix of the voltage sub series eigenvector matrix, and measure the distance of the characteristic covariance matrix between the two distribution variables, and form the distance matrix of the distribution variables. A class with few clusters is obtained by hierarchical clustering method, and it is judged as wrong distribution of line variable relationship. Experiment shows that the method can be used to verify the correctness of feeder-transformer relationship and has the value of wide application.

As a fault current detection device for a hybrid current-limiting fuse, the traditional pure silver arc trigger refused to operate under low overload current, so that low overload fault current detection cannot be achieved. In response to this problem, this article designed and processed a silver tinned arc trigger that successfully breaked under low overload current. Firstly, the working principle of the silver tinned arc trigger was analyzed. Then, according to the principle of electro-tinning, the electroplating process of the silver tinned arc trigger was designed, and the prototype of the silver tinned arc trigger with a rated current of 350A was obtained through electroplating. Finally, under the same experiment conditions, a 2450A low-overload pre-arc experiment was carried out on the silver tinned arc trigger and the pure silver arc trigger respectively. The comparative experiment results found that: the silver tinned arc trigger breaked after 23.3ms of current flow, and the pure silver arc trigger refused to break. On the one hand, it can be seen that the experiment results verify the correctness and reliability of the designed electroplating process, and the obtained silver tinned arc trigger prototype is qualified. At the same time, it also verifies the feasibility of the silver tinned arc trigger to realize the low overload fault current detection function.

In modern control system, PID, proportional-integral-derivative control, is normally used according to its straightforward structure, strong adaptability, and easy manipulation. However, in the real world, traditional PID controller might meet issues like low stability, weak anti-interference ability, and unsatisfying response capability. With the aim of solving the mentioned problems, fuzzy method is be applied into PID controlling and anti-interference technology is added as well. Firstly, according to the original physical model, mathematical model is established, and the transfer function is calculated out by applying appropriate motor parameters. Secondly, the methodology of fuzzy control is added into the servo motor system so self-adaptive PID controller is achieved. Finally, a concise comparison of the simulation results is carried out and our proposed fuzzy PID is proved to perform much better than the traditional one.

The three-dimensional finite element analysis method is used to calculate 72 schemes of the hydropower station cushion volute different cushion parameters, and the influence of cushion parameters on the natural vibration frequency of the hydropower station main structure is analyzed, and the following main conclusions are drawn: In the case of various cushion parameters, the low-order vibration mode of the hydropower station structure is the local vertical vibration of the floor. When the envelope angle of the cushion is the same, with the increase of the cushion deformation modulus, the corresponding natural vibration frequencies of each order increase slightly. The increase amplitude is small, and the maximum increase is only 0.36%, no matter the cushion is normal or failure. When the deformation modulus of the cushion is the same, with the increase of the cushion angle, the corresponding natural frequencies of each order all decrease slightly, but the decreasing range is also very small, and the maximum variation range is less than 0.2%. The variation of cushion parameters such as cushion range and modulus has little influence on the natural vibration frequency of the whole structure. The natural vibration frequency of cushion scheme is only slightly different from that of direct-buried scheme, and the cushion will not affect the stable operation of the unit.

Geomembrane material selection is the most critical problem of dam seepage prevention. This paper analyzes the key points of geomembrane selection from the aspects of geomembrane material, durability, thickness and composite mode, so as to provide some reference for the application of geomembrane in dam seepage prevention engineering. The key points of material selection include the following： the quality and uniformity of the internal components of the membrane and its adaptability to the deformation of the dam body, and should be combined with calculation to determine the thickness, avoid construction damage as far as possible to choose more than 1mm film thickness, the durability of geomembrembrances should be ensured by considering the effects of solar radiation, operating state, time effect, temperature, freeze-thaw and dry-wet changes on material properties, anti-aging measures, etc. The dam surface geomembrane seepage control is more inclined to use a composite factory of one cloth and one membrane, core rockfill dam geomembrane can be used in the form of two cloth and one membrane.

The traditional lightning arrester and fuse are installed separately with double cross arms, which has high installation material cost, long working time at height, and too many installation nodes are not conducive to later maintenance. The lightning protection fuse combination device shares an insulating base between the lightning arrester and the fuse, saving 1/2 of the material cost and installation time. A new type of thermal loss of excitation disconnector is built in the arrester part of the combined device, which can safely separate the aging arrester from operation, so that the arrester can be maintenance-free and live replacement.

Taking the South Taihu cyanobacteria interception project as the research object, combined with satellite imagery and onsite water quality monitoring, the water quality inside and outside the enclosure project and the cyanobacteria blocking effect are analyzed. The results show that the interception project has a significant effect on the interception of cyanobacteria. The average chlorophyll a concentration inside the enclosure is 56.6% lower than the average chlorophyll a concentration outside the enclosure. The satellite images of the same period also confirm that the cyanobacteria are effectively intercepted outside the enclosure; the wave-eliminating piles in the interception project keep the water in the enclosure in a relatively calm state, which is of positive significance for the development of water ecology in the enclosure. In general, the interception project will help improve the water landscape in the enclosed area, and the implementation of the project will have higher economic and social benefits for lakeside cities.

Light-gauge steel roof system has the advantages of light weight, good seismic performance and ease for installation, which is widely used in large-span space structures. However, the roof system is often damaged under typhoon scenarios. Numerous accidents show that roof failure is mainly caused by the failure of roof panel connectors. In this paper, based on an existing industrial building with a 360-degree standing seam metal roof system, the finite element model is established using spring elements, and the failure process is simulated. Comparing with the existing wind resistance test, the numerical simulation method is verified. The ultimate bearing capacity and anti-wind exposure ability of the roof system were introduced. It is shown that the finite element analysis results agree well with the experimental results, which can verify the finite element model. The research results can provide the reference for the wind resistance design and performance evaluation of the roof system with a 360-degree standing seam sliding clip.

China is an earthquake-prone country. Recent earthquakes such as Wenchuan have caused serious damage to power facilities. As the most important electrical equipment in UHV substations, transformers are facing a huge threat of earthquake disasters. As an important way to improve the seismic capacity for transformer equipment, seismic isolation technology can effectively solve the problem of insufficient seismic capacity of UHV transformers in areas with high seismic intensity. The soil-structure interaction is not considered in the current isolation design and evaluation of UHV transformers, which is not conducive to the refined seismic isolation design and evaluation of UHV transformers. Combined with the structural characteristics of UHV Transformer equipment, this paper put forward the seismic isolation test method of UHV Transformer with soil structure interaction, which provided a basis for the isolation test and isolation performance evaluation of UHV Transformer.

A linear analytical model is proposed to solve and optimize the magnetic field of halbach magnet semi-plug-in permanent magnet motor. On the basis of linear superposition, the magnetic field of a permanent magnet motor with a hypothetical linear material and double-layer embedded Halbach magnet is analytically calculated and optimized by using an isomolecular domain model. In addition, induced phase electromotive force and instantaneous electromagnetic torque are derived, which have good performance. The prediction results of linear analysis model agree well with those of finite element analysis.

The high proportion and large-scale access of new energy sources urgently requires the development of energy storage and other measures to enhance flexible regulation and electrical energy storage capacity. Pumped storage is currently recognized as the safest, most stable, most mature, most environmentally friendly and most economical way of energy storage, with the advantages of conventional synchronous power supply network source coordination. Vigorous development of pumped storage is of great importance and far-reaching significance to better serve the goal of "peak carbon dioxide emissions and carbon neutrality " and to ensure the safety of new power systems. By the end of 2020, China has 31.79 million kilowatts of pumped storage in operation and 50.63 million kilowatts in construction, which is the largest scale of pumped storage in operation and construction in the world. However, overall, the proportion of pumped storage in China's total installed power supply is still low, at 1.8%, and there is a big gap compared with the advanced level abroad, which still needs to be accelerated in the future. A re-examination of the functional positioning of pumped storage development will help to achieve the safe and healthy development of China's pumped storage industry and promote the goal of " peak carbon dioxide emissions and carbon neutrality ".

Geosynthetics have a great development prospect in seepage prevention of water retaining buildings because of their reliability and economic superiority. Geomembrane impermeable rockfill dam development at home and abroad also highlights the signs of development. This paper analyzes and summarizes two types of structure layout of geomembrane inclined wall rockfill dam and geomembrane core rockfill dam, which provide some reference for the design of geomembrane impermeable face rockfill dam.

The paper focuses on the implementation and application of the construction technology of 15 m ultra-high steel bone inclined column in a center in Shenzhen, which reduces the risk of safety accidents and ensures the construction quality and the appearance of finished products. The construction technology, process and operation points of high strength selfcompacting concrete high casting method are described through section hoisting of steel skeleton, reinforcement of cylindrical formwork and design of supporting formwork, which provides a reference case for the construction of the same type of inclined column with ultra-high steel skeleton.

Low permeability reservoir is affected by sand body distribution, reservoir fracturing, and strong inter-layer heterogeneity and other factors ^[1]. After water breakthrough, water cut rises rapidly, oil production capacity declines rapidly, and it is difficult to stabilize oil production. In order to slow down oil production decline, the liquid production increasing method of the Yan60-1 well area is studied. The research on liquid production increasing technology is carried out by means of theoretical curve ^[2], numerical simulation and balance diagram of injection-production pressure ^[3]. Then the reasonable liquid production increasing time, amplitude and method of well field is determined to guide the adjustment of water injection development in low permeability reservoir.

Energy Internet is a smart energy system that realizes the interaction of multi energy such as electricity, heat, gas, cold hydrogen, and multi coupling of source network, load and storage. But the combination of multi energy and multi field will lead to the access of high power electronic equipment, the fault conduction and coupling between cross energy, and the system operation scheduling is more complex and diverse. Based on this, this paper studies the key technologies of energy Internet fault recovery considering multi energy complementarity and security improvement, and proposes the fault recovery strategies of "pre disaster prevention and reinforcement", "emergency control" and "post disaster rapid recovery"; Based on the safe operation of energy Internet, the main carbon reduction effects of energy internet construction are proposed, which provides technical support for the construction and safe operation of energy Internet in China, and has strong research value and promotion value.

In order to analyze the performance of permanent magnet synchronous motors (PMSM) with different phase numbers under the condition of loss of excitation, based on the mathematical model of PMSM with different phase numbers, a PMSM simulation model based on Matlab/Simulink platform was built. The model takes the number of motor phases as the input parameter, and obtains 3-phase and 6-phase PMSM by changing the connection mode of the motor. Then, 40% demagnetization is carried out on the 3-phase and 6-phase PMSM, and the current characteristics of the motor under normal operation and 40% demagnetization fault are obtained. Based on the current characteristics of motors, the stability of motors with different phase numbers under the condition of demagnetization is analyzed.

The national development and reform commission proposed to pilot promote the large-scale development of distributed photovoltaic in the whole village, town and county, and pointed out that promoting the pilot of large-scale development of distributed photovoltaic in the whole county is an important measure to implement the strategic goal and task of "carbon peak and carbon neutralization".In order to carry out in-depth analysis and research on the impact of roof distributed photovoltaic construction in the whole county, provide suggestions and decisions for the company and Energy Bureau to promote roof photovoltaic construction, this paper This paper takes village level roof photovoltaic as the research object, carries out research from the aspects of village overview, photovoltaic access overview, load and electricity of village, photovoltaic income and impact of photovoltaic access on Power Grid.

The brain-computer interface can create a connection between the central nervous system of a human or animal and an external device to exchange information. We designed a complete set of brain-computer interface collection components Neurochat Series, using the latest 3D printing technology and high-precision CNC to reduce the complexity of production, while ensuring the collection effect, reducing the time for electrode production. With the help of Neurochat series, the signal collection from brain waves to local field potentials and neuron spikes is realized, which is very suitable for obtaining EEG information data in animal experiments.

This paper proposes an integrated energy service method for thermoelectric coupled systems considering demand response. First, based on the framework of a typical thermoelectric coupling system, the energy hub equation of the system source load energy is established; second, the minimum system operating cost is selected as the optimization objective, and the transferable load participation ratio and the convertible load participation ratio are the load side constraints. Conditions, to achieve the mathematical modeling of the system; finally, the results of the calculation example show that the total cost of the system is reduced by 35.7% at the high transferable load participation ratio and the low convertible load participation ratio, and the optimal energy consumption of the thermoelectric coupling system is realized.

MAC accounts for 7% - 20% of the energy consumption and emission of fuel vehicles. However, With the trend of electrification of automobiles, MAC emissions will further increase. In addition, the refrigerant R-134a for MAC is a powerful GHG, and low-GWP alternatives include R-744 and R-1234yf. Evaluating the emission reduction potential of the life cycle of MAC is of great significance to carbon emission reduction. Based on the LCCP, this paper constructs a electric car MAC emission reduction benefit evaluation model, and analyzes the life cycle emission reduction potential and cost of low-GWP refrigerant MAC in different climate regions. The results show that the R-744 system has the largest emission reduction potential in cold climate regions, with a reduction of about 3.7tCO_2eq of single-vehicle emissions, while the R-1234yf system has the largest reduction potential in areas with higher temperatures, and the reduction of single-vehicle emissions is about 1.4tCO_2eq. In addition, the life cycle carbon emission reduction cost of alternative refrigerants can be as low as 300 ¥/tCO_2eq, which has cost advantages compared with other emission reduction technologies.

In this paper, a simulation room is proposed to study the snow crystal morphology, snow crystal growth, snow quality and atomization characteristics of the gas-liquid internal mixing nucleon under different temperature, humidity and operating parameters. Preliminary snowmaking experiments were carried out, and the snow was produced successfully, and the snow crystal morphology was consistent with previous studies. The simulation room provides a certain reference value for the scholars who study the mechanism of snow making in high temperature areas to build the experimental platform.

This paper mainly studies the energy management of regional integrated energy system with high proportion of renewable energy access. This paper proposes an energy management optimization strategy for regional high proportion renewable energy systems. The goal of this strategy is to minimize the comprehensive electricity cost in the region within a certain time period, and consider diversified distributed power sources and load types, such as wind power generation, photovoltaic power generation, fuel type controllable power generation, battery storage, electric vehicle and interruptible charge. In this paper, a high proportion of renewable energy system in a region is taken as an example to carry out case analysis, the results show that: the strategy can fully tap the renewable energy power generation space, maximize the local consumption of renewable energy power generation, and the strategy has a certain engineering practicability.

Under the influence of policies such as "new infrastructure", great changes have taken place in the energy Internet with power grid as the core, and with the adjustment of industrial structure and the continuous growth of various forms of load, the analysis of load characteristics becomes complicated. In this paper, a method based on load characteristic analysis of load forecasting, first through the feeder DBScan algorithm for city of Jiangsu province for clustering analysis, then the load characteristic analysis was carried out on the differentiation of the industry, the influence factors of different characteristics of electricity industry is also different, finally according to different industry choose different model for load forecasting, The validity of the proposed method is verified.

Large-scale energy storage technology is a key supporting technology for my country's renewable energy power generation and utilization, and an important driving factor for the energy system to achieve climate-neutral transformation. Driven by both the cost reduction of renewable energy and energy storage technology, the electrochemical energy storage industry has developed quite rapidly. Based on this background, starting from the characteristics of different energy storage media, summarize the technical characteristics and structural characteristics of electrochemical energy storage, and study the current problems and solutions of energy storage converters, and then through the use of energy storage in different application scenarios The function and economy are analyzed, and finally the development of electrochemical energy storage technology is prospected.

Phase change energy storage has become one of the most important means to improve the efficiency of energy use in buildings. In order to reduce building energy consumption, a mathematical model of the one-dimensional phase change wall in an office building in cold region is developed, with the MATLAB program for solving the model. Using the validated mathematical model, the heat transfer process of the phase change wall is simulated in Beijing, China, a representative city in the cold climate zone. The results of the study show that in the cold region (Beijing), the heat transfer is minimized in the whole year when the outer layer is made of paraffin wax (C16-C28) with a melting point of 43°C and the inner layer is made of 4cm thick octanoic acid with a melting point of 16.3°C. Compared with non-phase change walls, the heat transfer on the inner surface decreases by 16.6 % in summer conditions and by 18 % in winter conditions. The simulation results provide a feasible solution for optimizing the thermal performance of phase change walls in cold region.

Taking a trapezoidal distributor with one side inlet as the research object, the effects of the diameter of inlet pipe and distribution hole on the velocity field, pressure field, liquid equalization performance and resistance performance of the distributor were studied. The simulation and analysis results show that the velocity gradient and pressure gradient near the liquid inlet pipe change greatly, and the flow rate of the liquid distribution hole near the liquid inlet pipe will decrease seriously; The results show that the pressure drop of the distributor decreases with the increase of the diameter of the liquid inlet pipe when the diameter of the liquid inlet pipe is in the range of 47mm~110mm; With the decrease of the diameter of the distributing hole, the overall liquid distribution performance of the distributor can be significantly improved, but the overall pressure drop of the distributor will increase. The simulation results show that the diameter of the inlet pipe and the diameter of the distributing hole have a great influence on the performance of the distributor, which can provide an important direction for the optimization design of this type of distributor and is of great significance for engineering application.

This paper mainly studies the capacity allocation of off-grid electric vehicle charging stations. On this basis, a capacity allocation optimization model of "wind-light-storage-charging" multi-station fusion system is proposed. The model aims to minimize the cost of investment, construction, operation and maintenance of charging stations, and takes into account the local wind and light resource endowment, charging load demand, reserve capacity and other random factors and constraints. In this paper, the model is implemented based on GAMS software, and a typical case is analyzed to verify the correctness and effectiveness of the method.

To investigate the effects of boiler designs on the performance of the hybrid SNCR-SCR process, a 65 MW gas-fired boiler was studied, which uses the blast furnace gas generated from a steel refinery as the fuel. A full-size 3-dimensional model of the boiler was established, and the EDC model was employed to consider the turbulent interaction and the detailed SNCR and SCR reactions. The relative errors between the modeling results and the design data are less than 10% and are in an acceptable range. The results show that, compared to the boiler arranged with a fuel preheater, the boiler equipped with a low-pressure economizer has a slightly higher SNCR DeNOx efficiency, an obvious lower SCR DeNOx efficiency, and a lower concentration of the escaped ammonia.

Based on the finite element method, the top earth pressure and shear stress on the side of wall of trapezoidal trench-buried culvert are analyzed. The results show that the earth pressure coefficient at top of trapezoid trench-buried culvert decreases with the increase of height and dip angle of trapezoidal trench, and increases with the increase of trench width. The shear stress on the side wall of culvert increases with the increase of filling height and trench width, decreases first and then increases with the increase of trench height. It is recommended that culverts use larger trapezoidal trench inclination angle, smaller filling height and trapezoidal trench width as far as possible in engineering practice.

Global development of the offshore wind energy is devoted to applying. As one of the important foundation types of offshore wind turbine, the suction bucket foundation has been widely used in recent years. However, the suction bucket foundation can not be transported by the common barge like other foundation types due to its large opening at the foundation bottom. Additionally, little research work has been done by now with respect to the transportation device of the suction bucket wind turbine foundation. Thus, this paper presents a floating transportation equipment (FTE) for the negative pressure suction bucket foundation (NPSBF) of offshore wind turbines, and the basic design and main transportation means are introduced. The hydrodynamic characteristics of integrated FTE-NPSBF structure are comprehensively studied from the metacentric height, static stability and RAO performances. The ability of FTE as a transportation aid to provide stability for the NPSBF is verified, and the vibration reduction measures under the condition of wave resonance during the floating transportation process are given.

The karst development degree in the factory area is extremely strong, the borehole dissolution rate is 67, the borehole line karst rate is 20.8 and the average buried depth of the karst cave is 27.59 m, which belongs to the deep karst. In both horizontal and vertical directions, the caverns are beaded, and the holes reveal an average of 3 to 4 caverns, and the roof thickness of the caverns is on average 1.04m.The roof is thin and broken, and the collapse of a single cavern will inevitably lead to the stability of the other caverns. In order to solve the problem of pile foundation stability, in the course of pile foundation construction, according to the height of the cave and the filling condition, according to the following principles:1) Schist, clay scheme treatment (H ≤ 2m) ;2) Low grade concrete treatment (2 m < H ≤ 4 m); 3) Hydrostatic chemical grouting scheme (4 m < H ≤ 10 m); 4) Casing follow-up wall protection scheme (H < 10 m).

Interior V-type permanent magnet (PM) machines are widely used in new energy vehicles due to their merits of high efficiency, high power density, and wide speed range. To meet the requirement of the elderly mobility scooter, a 380V/2.2kW V-type interior PM machine is designed and analyzed in this paper. Firstly, the structure parameters of the Vtype interior PM machine are derived. Then, the basic electromagnetic properties of the PM machine including the no-load air gap flux density, back-EMF, armature reaction flux density, output torque, etc. are investigated. Finally, the dimensions of the V-type PM including the width, thickness, and inclination angle are optimized to obtain better electromagnetic performance. Compared with the performance before optimization, the torque ripple of the PM machine is reduced by 33.53% and the efficiency is improved by 0.88% after optimization.

The vertical ultimate bearing capacity of a single pile is an important parameter required in the design of pile foundation. The vertical compressive static load test of a single pile is the most reliable method to determine the vertical ultimate bearing capacity of a single pile. However, the load test cost is high and the cycle is long. In the early stage of small and medium-sized projects or large-scale projects, the conditions for carrying out the vertical compressive static load test of a single pile are generally not available. Based on the geotechnical engineering of a coal-fired power station in Southeast Asia, the vertical ultimate bearing capacity of a single pile is estimated by using the results of cone penetration test (CPT) and standard penetration test (SPT), and the ultimate bearing capacity is tested by high strain dynamic test. Compare various estimating value and high strain dynamic testing value to static load test value with ultimate vertical bearing capacity of a single pile, and then obtain the reliability of vertical ultimate bearing capacity of a single pile by means of CPT and SPT in this area. By means of the research results of this paper, obtain the vertical ultimate bearing capacity of PHC pipe pile quickly and accurately in this area for similar engineering design. Ultimately achieving the goal of shortening the construction period and reducing geotechnical investigation cost.

Offshore oil and gas resources are major sources of future global oil and gas increments. Suction bucket foundations are a new type of foundation that is widely used for offshore oil and gas exploitation platforms. Such platforms are often subjected to dynamic loads caused by storms, waves, or earthquakes, which cause the instability and liquefaction of seabed sand layer foundations. These loads jeopardize the safe operation of offshore oil and gas platforms. For this reason, the cyclic elastoplastic constitutive model is adopted in the ocean liquefaction stratum, in consideration of the foundation liquefaction and large deformation effects. To study the changes in the excess pore water pressure of the suction bucket foundation in different ocean liquefaction formation thicknesses under the action of seismic loads.

The regional energy internet is coupled with natural gas, hot and cold, and other technologies complementing the core power system. It is conducive to the complementary advantages of multiple energy sources and is significant for transforming its energy structure. The extraction of key indicators in various aspects of the regional energy internet and the evaluation of comprehensive benefits are essential issues that need to be resolved urgently. Firstly, this paper summarizes existing researches and introduces a typical physical architecture of regional energy internet. Secondly, the evaluation indicator system of regional energy internet is established to offer a fundamental presupposition for the exhaustive evaluation, based on numerous research on the energy internet evaluation. Technology, economy, environment, and society are scrutinized in the established indicator system. Then use the ISM model to sort out the indicator system. Finally, it summarized the significance of the comprehensive indicator system of the regional energy internet in the evaluation process to provide a reference for related research and projects.

Reasonable determination of the maximum transmission active power and maximum transmission distance of the transmission line is essential for guiding the design and site selection for renewable energy stations. Based on the characteristics of changes of the operating conditions of renewable energy stations, this paper studies on the effects of static power angle stability, line voltage drop, capacity rise effect, and cable capacitor charging on the maximum transmission active power and maximum transmission distance of the output line. The method to calculate maximum transmission active power and maximum transmission distance for output line is developed. The maximum transmission active power of the output line and the maximum transmission distance are inversely related. By rationally adjusting the planned capacity or the transmission distance of the new energy power station, it can ensure that the electric energy of the new energy power station is effectively consumed.

Aluminum alloy material has its own light weight, excellent corrosion resistance and easy to recycle advantages; concrete material has the characteristics of durability, good plasticity and high compressive resistance. Therefore, the composite structure formed by aluminum alloy tube filled with concrete has good corrosion resistance and beautiful appearance, which is a kind of environment-friendly structure with excellent performance and good promotion prospect. In this paper, through the axial compression test of rectangular aluminum alloy tube concrete short column, the working performance, failure law, load and displacement as well as load and strain of the component are studied.

In recent years, the Internet of Things technology and embedded technology have developed rapidly, and the two complement each other to jointly promote the expansion and application of technology in the fire protection industry. Traditional smoke detection equipment has a single working mode, and the contradiction between the false alarm rate, the false alarm rate and the sensor sensitivity cannot be resolved. The construction and subsequent maintenance are difficult, and it no longer meets the market demand for modern fire protection. Therefore, based on the ZYNQ7020 series CPU, it can perform local on-site image recognition and analysis, and effectively improve the anti-interference ability of equipment such as dustproof and waterproof steam. The application of the stand-alone management system can respectively improve the online rate of the equipment, the wireless networking capability and the power adaptive management capability, provide a reliable and realistic basis for the judgment of the first scene of the fire, and improve the emergency management capability of the rescue team.

Permanent magnet synchronous motor (PMSM) demagnetization failure makes it unable to be used in high reliability applications if it cannot be detected in the early stage. To solve this issue, this paper combines Hilbert-Huang transform (HHT) and empirical wavelet transform (EWT) to extract fault feature and diagnose PMSM demagnetization faults and analyzed the feasibility of this method. The simulation results prove that the EWT-HHT method can be effectively diagnose demagnetization failure of PMSM.

To study the influence of the non-uniform demagnetization of permanent magnets (PMs) on motor performance, this paper takes a three-phase eight-pole Permanent Magnet Synchronous Motor (PMSM) as the research specimen. The influences of back electromotive force (Back-EMF) and radial magnetic density with different grades and types of demagnetization are analyzed. The numerical results prove that as the grade of non-uniform demagnetization increases, the back-EMF and radial magnetic density gradually decrease, after FFT, according to the changes law of the amplitudes of some harmonics frequency of the back-EMF, it should be determined whether the motor has non-uniform demagnetization. This research could provide a guideline for fault diagnosis of motor demagnetization.

The switching harmonics generated by the on-off and off of the switching tube of the chopper-controlled magnet power supply will affect the control accuracy of the magnet power supply for the particle beam current. The switching harmonics are mainly concentrated near the switching frequency and its sideband. In order to effectively suppress the switching frequency and sideband harmonics, three passive filters are studied. The three passive filters are based on BUCK buck circuit, and the harmonic bypass effect of switching frequency and sideband frequency is achieved by low-pass filtering and series resonance, thereby reducing the amplitude of load current ripple. The simulation results show that the designed three passive filters have good suppression effects on the switching frequency and sideband harmonics.

Inertial navigation system (INS) aided by odometer can achieve ideal accuracy in pipeline surveying, and hence is widely used. However, because of mechanical manufacturing errors, there are installation angle errors between INS and odometer as well as the odometer scale factor error, which will decrease the system position accuracy. To achieve high accuracy, these errors need be calibrated periodically. In this paper, a pre-calibration method based on similarity principle is proposed, which is used for odometer installation error and scale factor calibration in pipeline probe autonomous navigation system. The proposed method has no special requirements for the number of landmarks. The effectiveness of the proposed method is verified by the simulation and filed test. The field pipeline test shows that the position accuracy of the integrated navigation system is less than 0.5%D, which satisfies the application of long-distance horizontal position in pipeline surveying.

In order to ensure the safe operation and timely maintenance on mine flameproof dry-type transformer, we use MATLAB as the platform to get the simulation and to complete the edition of prediction program. After the comprehensively considering the accuracy and timeliness of the algorithm, our final optimization plan is: the GM(1,1) model must be optimized in one aspect: the accumulated order optimization, and then corrected the residuals. Compared to the traditional GM（1,1）model, the optimized and corrected GM(r,1) can improve the accuracy of the prediction result and guarantee the quick reaction of the pre-warning system before the occur of failures. Using this model enables the system to predict the potential faults in a certain period of time in the future, which can improve the actual operation efficiency of mine flameproof dry-type transformer and prolong the transformer’s working life.

In sensorless control, sliding mode observer is widely used because of its insensitivity to parameter changes and strong robustness. For unnecessary high frequency chattering and the lack of accuracy in calculation of rotor position and machine speed in the conventional sliding mode observer, a new sliding mode observer based on the new constant velocity reaching law is used to suppress the high frequency chattering of the machine system. A new constant speed reaching law is designed to replace the conventional constant speed reaching law and it is introduced into new sliding mode observer. This method improves the approaching speed of sliding mode and reduces the high frequency chattering of conventional sliding mode observer. In addition, the arctangent function is used to estimate the position of the machine rotor, and the phase compensation for the Angle position error of the machine rotor is carried out. The simulation results show that compared with the Conventional sliding mode observer, the proposed new sliding mode observer is more stable and has better control performance.

The working environment of underwater vehicle is very bad, so it is necessary to diagnose its fault effectively in time. Underwater vehicle system has the characteristics of nonlinear and time delay, it is difficult to establish accurate mathematical model. On the basis of the sensor data, such as velocity of underwater vehicle,propeller speed,the motor temperature,the motor current ,the voltage and current of the master battery and Power cell, a fault diagnosis method for underwater vehicle based on Kernel Principal Component Analysis（KPCA）is proposed. Linearly indivisible data in the original low-dimensional space are mapped to high-dimensional space by the radial basis (Gaussian) kernel function. Simulation results show that the fault variables can be identified and separated more accurately and quickly by KPCA. Compared with traditional principal component analysis, KPCA has more advantages in fault diagnosis of underwater vehicle system.

Pressure vessels usually work in harsh environments with high pressure and corrosion, so that their safety and reliability are very important. At present, the surface detection of pressure vessels is mainly based on the internal surface detection, and most of them are done manually. If the height or diameter of the tank is greater than the height of the human body, scaffolding or other climbing devices need to be built in the tank with disadvantages including danger and low efficiency. Therefore, most of the wall-climbing magnetic particle automatic inspection robots currently developed are wall-climbing robots with additional inspection equipment. According to several shortcomings, a portable magnetic particle inspection robot with a magnetic yoke as the skeleton has been developed. The robot is suitable for the detection of pressure vessels with smaller diameters (such as 2 meters-4 meters), and can improve work efficiency, reduce labor intensity, and thus enjoys better application prospect.

As the core parts of the drive system of electric vehicles, the electromagnetic and temperature rise properties of the drive motor greatly affect the stability of the motor operation. According to the actual working conditions of electric vehicles, a permanent magnet synchronous motor with continuous power of 35kW and rated speed of 3500r/min was designed. Based on finite element analysis and equivalent thermal network method, the model was simulated and analyzed by using motor CAD software. Through comparative experiments, the influence of each structural parameter change on the operation performance of the motor was studied. The motor efficiency increases from 94.57% to 95.34% in the comprehensive design optimization scheme. The torque ripple decreases from 18.6N·m to 5.3N·m, which decreases by 71.5%. The total loss decreases from 2081W to 1750W, with a decrease of 15.9%.The stability of motor operation is improved.

By analyzing the structural principle of vehicle high-speed search photoelectric panoramic mirror, the MATLAB/SIMULINK simulation research on the fast mirror control and vehicle-mounted image stabilization control strategy based on the scanning gaze imaging technology is carried out, which lays the foundation for the next physical development.

Traditional AC system protection and conventional DC transmission system protection principles and methods are difficult to apply to current DC transmission lines. First, analyze the transient characteristics of DC transmission line faults, and then extract high-frequency transient voltage components at the moment of fault through wavelet changes. Based on the wavelet energy values of the faults inside and outside the zone, propose a fault identification method. A DC fault protection scheme based on the reclosing criterion. A fault protection algorithm based on the combination of DC circuit breaker and transient traveling wave is given. Finally, a four-terminal voltage source converter-type DC grid model was built on the Matlab / Simulink simulation platform, and the feasibility of the protection principle was verified through simulation experiments. The advantages are of great significance for the rapid determination of DC transmission faults.

Radio frequency design has an important position in wireless mobile communication design. With the rapid development of microelectronics and communication technologies, the degree of integration of radio frequency circuits is getting higher and higher. For wireless communication systems, new challenges such as high speed, low cost, wide bandwidth, and small size are presented. Therefore, based on the basic principles of wireless communication radio frequency technology, this article conducts research and design on radio communication radio frequency receiving systems, modularizes radio frequency receivers and radio frequency transmitters, explores the structure and principle of each module, and fundamentally improves each one. Modular fast performance, realizes the wide bandwidth and high speed of wireless transmission radio frequency transceiver system, and gives a complete and feasible design scheme of the wireless transmission system.

In this paper, a sensorless control method based on sliding mode observer (SMO) is proposed for permanent magnet synchronous motor (PMSM), in which continuous Sigmoid function is substituted for saturation function as switching function. A sliding mode observer is used to identify and determine the rotor position instead of the traditional position coding plate, and the operation system is started through I/F. Finally an experimental platform was built, and the test results were analyzed. It was verified that the proposed method has the advantages of smooth starting, accurate current observation model establishment and improved robustness of SMO control.

The multi-module series-parallel combination system suitable for high voltage and large current has good application effect and performance level, high research value, and vast prospects. In this paper, an isolated full-bridge DC/DC converter is used as a single module to form an Input series output paralleled (ISOP) combined system. A three-loop control strategy is designed to achieve the input voltage sharing and output current sharing of the system. The simulation models of the three modules are established by MATLAB Simulink, and the voltage jump experiment is carried out. The experimental results show that the three-loop control strategy has a good setting effect, which can ensure the system ensure the steady-state operation and have excellent voltage and current sharing effects.

To study the influence of the uniform demagnetization of permanent magnets (PMs) on motor performance, this paper takes a three-phase eight-pole Permanent Magnet Synchronous Motor (PMSM) as the research specimen. The influences of back electromotive force (back-EMF) and radial magnetic density with different grades of demagnetization are analyzed. The simulation results show that as the grade of uniform demagnetization increases, the back-EMF and radial magnetic density gradually decrease, after FFT, according to the changes of the amplitude of some harmonics of the back-EMF, it should be determined whether the motor has uniform demagnetization. This research conclusions could provide a guideline for fault diagnosis of motor demagnetization.

CNC lathe is a kind of high precision, high efficiency automatic machine tool, widely used in machining. It is composed of processing program carrier, NUMERICAL control device, servo and measurement feedback system, machine tool body and numerical control lathe auxiliary device, so its maintenance and fault diagnosis is also very complicated. In this paper, from the lathe can not return to the datum point, PLC and tool rest, analyze the possible causes of these faults, and put forward the solution, which has reference value to the personnel engaged in NC maintenance work.

In view of the immature control system of permanent magnet brushless DC motor and the instability of the control system, this paper proposes a permanent magnet brushless DC motor based on phase advance correction controller, designs the controller to realize the closed-loop automatic control of the system, and proves the effectiveness of the control strategy through modeling and simulation, so as to solve the instability of the control system.

In low-voltage shore power supplies, the inverter are often controlled using a dual-loop control method. The dual-loop control method is power outer-loop and voltage inner-loop control. The power outer loop contains the power calculation module and the droop control module. The droop control is a simulation of the external characteristics of the synchronous generator, where the voltage and frequency values are obtained from the P-f and Q-U droop curves, respectively. Droop control does not require communication and coordination between devices and is simple and reliable. In this paper, we improve the droop control to improve the smoothness of the shore power supply and ship's grid connection.

The uneven electromagnetic force inside the motor is the main cause of the vibration and acoustic noise of the PMSM (PMSM).To study the problem of increased vibration and acoustic noise caused by variations in the radial electromagnetic force density caused by a partial demagnetization fault of a PMSM, the finite element method (FEM) is used to study the radial flux density and radial electromagnetic force waves on the stator surface of a 4-pole 24-slot embedded PMSM. The changes of electromagnetic force waveform and harmonic order are analyzed when PMSM is partially demagnetized. The measurement results show that the fundamental wave amplitude of radial electromagnetic force on the stator surface increases, and fractional harmonics appear, with the increase of demagnetization grade.

When the temperature of supercritical thermal power unit is overheated, it is easy to cause power station failure, and even fire in serious cases, resulting in great potential safety hazards. Based on this, it is necessary to optimize the problem of poor real-time monitoring of thermal power unit temperature overheating. This paper proposes a real-time monitoring method for the temperature and overheating of supercritical thermal power units. Aiming at the problem of overheating of supercritical thermal power units, this paper optimizes the online temperature monitoring system, the online stator winding end vibration monitoring system and the online generator gas analysis and monitoring structure installed in the steam turbine generator unit of the power station. Based on the above optimization, the time and temperature tracking detection algorithm for thermal power units is improved. Through system application analysis, different online monitoring methods are compared, and different online monitoring methods can be flexibly selected to ensure the safe operation of the unit. The experiments show that the real-time monitoring method of temperature overheating of supercritical thermal power generation unit has high practicability in the process of practical application, can better carry out high temperature early warning and solve the problem of poor monitoring effect.

This paper discusses the fine modelling and control of three-phase PWM inverter by means of average model method. First, the average model method is used step by step to make it easier to read in the power stage design. The second part is the controller design which has the inner current controller and the outer voltage controller to help controlling accurately. Finally, the linear and nonlinear loads were tested respectively on the basis of fine modelling, being meaningful to do the research of nonlinear loads. The simulation results have shown that the average model method is an effective research solution of three-phase PWM inverters, which can be easily generalized to modelling and control of any other PWM inverters.

The current expert system-based power grid fault analysis knowledge model database is difficult to generate, update and maintain, part of the work on the establishment of the substation main wiring information database can still only be done manually by specialized personnel, this method is not only time-consuming, but the accuracy of the database establishment is not high, and it is difficult to correct errors. In response to the above problems, this paper proposes a main wiring information data structure for the model and its automatic generation method, improves the versatility and automation of the power grid fault analysis knowledge model, and reduces the amount of repetitive work in the development process.

There is a form to cross the river both with bridge and tunnel at same postition，which is the backbone of cross-regional traffic and provides higher traffic capacity. However, how to use reasonable control measures and balance the traffic flow distriubution of the bridge and tunnel is a significat problem. To address this issue, we proposes a bridge-tunnel linkage control system with holographic monitoring and perception, deep integration of multiple sources, collaborative management, efficient control, and intelligent decision-making by configuring intelligent sensing facilities and equipment based on the new generation of information such as cloud computing, Internet of Things, mobile Internet, and big data. The system fully realizes the coordinated management and control of people, vehicles, roads, and the environment, thereby improving operational safety and operational efficiency, and reducing operational energy consumption.

With the outbreak of COVID-19, the phenomenon of crowds has attracted much attention. To study the impact of fire on evacuation density of teaching building under epidemic situation, a university teaching building was simulated by FDS. The influence of smoke exhaust window opening on fire development was studied by analyzing the law of smoke, temperature and CO concentration, and the allowable evacuation time ASET of teaching building was obtained. Evacuation simulation using Pathfinder determines the required evacuation time RSET and analyzes congestion points, making evacuation improvements from two aspects: reducing the proportion of people and planning evacuation. The results show that CO concentration is an important factor affecting the ASET of teaching buildings, and it can extend the ASET of teaching buildings when the top smoke exhaust window is open; The evacuation congestion points of teaching buildings are mostly concentrated in the classroom exit, the east corner of the passage, the corner of the stair platform and the corner of the west exit. Although reducing the proportion of people can achieve safe evacuation, it can not meet the needs of the evacuation density under the epidemic situation. Through further evacuation planning, it can not only meet the requirements of safe evacuation, but also reduce the evacuation density, which provides a reference for the safe evacuation of teaching buildings under the epidemic situation.

Aiming at the problem of underequent synchronization in ultra-high-layer jacking platform construction, based on the site conditions, the main reason is due to the unevenness of the stack, which causes the tape lifting force. For the reasons, the jacking platform system is optimized, and the fuzzy PID control calculation is combined on the control of the "master from mode", and the design model uses the MATLAB / SIMULINK software to simulate, the result shows that the jacking error of the new jacking system is almost 0.The new jacking system meets the requirements of synchronous jacking, speeds up the jacking speed and eliminates the potential safety hazards caused by asynchronous jacking.

In the process of underground cavern excavation, the relaxation deformation and strain of surrounding rock are the focus of engineers and technicians[1].This paper introduces a continuous strain monitoring device and technology modified by grating optical fiber displacement sensor. Using this technology, the continuous displacement measurement values along the full hole depth of the instrument buried measuring hole can be obtained, and then the continuous strain value can be calculated by using the instrument installation and embedding gauge distance. The application of this technology in practical engineering has obtained good monitoring results, which provides a scientific and reliable basis for the control of excavation strength and the determination of support scheme. It can provide a useful reference for similar engineering cavern surrounding rock monitoring.