This paper is focused on a design of a piezoelectric vibration energy harvester with an additional nonlinear stiffness. Common piezoelectric energy harvesters consist of a cantilever with piezoceramic layers and a tip mass for tuning up the operation frequency. This system is excited by mechanical vibrations and it provides an autonomous source of electrical energy. A linear stiffness of the cantilever has very narrow resonance frequency bandwidth which makes the piezoelectric cantilever sensitive to tuning up of the resonance frequency. It could be tuned only for one narrow vibration frequency bandwidth. The piezoelectric vibration energy harvester with nonlinear stiffness could provide the resonance frequency bandwidth wider and it allows energy harvesting from the wider bandwidth of excitation vibrations. The additional nonlinear stiffness is implemented by using a set of permanent magnets. A simulation and an experiment were performed and the results show a wider resonance bandwidth. However, it depended on direction of vibration frequency sweeping. The frequency bandwidth is more than three times wider but there is only a half resonance amplitude of oscillations. That means that the maximal harvested power is lower but the average harvested power around resonance frequency was higher which was the goal of this research.
The paper deals with analyses and evaluation of vibration energy harvesting systems which are based on electromagnetic and piezoelectric physical principles off electro-mechanical conversion. Energy harvesting systems are associated with wireless sensors and a monitoring of engineering objects. The most of engineering objects operate with unwanted mechanical vibrations. However, vibrations could provide an ambient source of energy which is converted into useful electricity. The use of electromagnetic and piezoelectric vibration energy harvesters is analyzed in this paper. Thee evaluated output power is used for a choice of the efficient system with respect to the character of vibrations and thee required power output.
<p> The artificial cochlear implant is the only way how to get lost hearing back in some cases. Existing artificial cochlear devices use two separated parts for this purpose: a signal processing unit with transmitter and an implantable receiver with electrodes. This approach is applicable but not fully implantable. A new complex approach to design of a fully implantable artificial cochlea is described in this article. </p> <p> The proposed artificial cochlea consists of many subcircuits which have to be designed in close context to reach optimal performance and the lowest power consumption. Power consumption should be decreased to a value which allows using cochlear implant as a zero-powered system. A combination of micro-mechanized diaphragm filter bank, possible energy harvesting power source and especially ultra-low power processing electronics is presented in this article. A unique technique for nerve stimulatory output signal generation is discussed. This new technique named charge push-through electronics should use the major part of energy generated by energy harvesting subcircuit for output useful signal generation with minimal undesirable current. </p><p> Mechanical parts of the subcircuits were simulated as complex electro-mechanical simulation models in ANSYS, CoventorWare, Matlab and SPICE environment. First, the real energy harvesting power source (human motion and temperature) behavior was measured. The model of this behavior was created in simulation environment and then the whole electronics simulation model for energy harvesting circuits was estimated. Next, signal processing circuits powered from energy harvesting power source were designed and simulated. The new signal processing circuits were simulated in relation to the results of complex electro mechanical diaphragm and SPICE energy harvesting power source simulation. </p>
The paper deals with an efficiency calculation of an electromagnetic vibration energy harvesting system. The efficiency of this system is defined, measured, calculated and the energy harvesting model is verified. The effect of individual harvester’s parameters is observed with aim to improving design with the same volume and weight of the energy harvester. The impact of vibration energy harvesting systems has limitations in a resonance operation and a level of used mechanical vibrations. However the efficiency improvement could be useful for the wider using vibration energy harvesting systems in applications with lower level of mechanical vibrations.
This paper assesses the feasibility of the energy harvesting principle for the development of an autonomous power supply unit for a new generation of biomedical devices, e.g. artificial cochlear implants. Requirements for the harvester are set based on a research of power demands of state-of-the-art medical devices. Feasible methods of the energy conversion are then reviewed, and a simulation model of the generic energy harvester is developed. Acceleration in the head area of the user is measured and used as an input excitation for the model. Possible course of the follow-up research is outlined based on simulation and measurement results.
The aim of this paper is to examine the performances of thermoelectric generator based on microelectromechanical
systems technology (MEMS) in wide range of operational conditions. The goal is to evaluate capability of this
technology for a development of an independent energy source for aircraft applications. Complex overview of MEMS
TEG properties obtained by computational modeling, simulations and experimental testing is utilized to define critical
phenomena of MEMS TEG technology.
This paper deals with an energy harvesting system for avionics; it is an energy source for a unit which is used for
wireless monitoring or autonomous control of a small aircraft engine. This paper is focused on development process of
energy harvesting system from mechanical vibrations in the engine area. The used energy harvesting system consists of
an electro-magnetic energy harvester, power management and energy storage element. The energy harvesting system
with commercial power management circuits have to be tested and verified measured results are used for an optimal
redesign of the electro-magnetic harvester. This developmental step is necessary for the development of the optimal
vibration energy harvesting system.
This paper deals with an optimization study of a vibration energy harvester. This harvester can be used as autonomous
source of electrical energy for remote or wireless applications, which are placed in environment excited by ambient
mechanical vibrations. The ambient energy of vibrations is usually on very low level but the harvester can be used as
alternative source of energy for electronic devices with an expected low level of power consumption of several mW. The
optimized design of the vibration energy harvester was based on previous development and the sensitivity of harvester
design was improved for effective harvesting from mechanical vibrations in aeronautic applications. The vibration
energy harvester is a mechatronic system which generates electrical energy from ambient vibrations due to precision
tuning up generator parameters. The optimization study for maximization of harvested power or minimization of volume
and weight are the main goals of our development. The optimization study of such complex device is complicated
therefore artificial intelligence methods can be used for tuning up optimal harvester parameters.
This paper deals with an electromagnetic vibration energy harvester which generates electrical energy from ambient
vibrations. This harvester provides an autonomous source of energy for wireless applications, with an expected power
consumption of several mW, placed in an environment excited by ambient vibrations. A tuned up design of the harvester
with an electromagnetic converter provides sufficient generating of electrical energy for wireless applications. The
output power depends on a frequency and level of the vibration and sensitivity of the energy harvester. Our harvester
includes a unique spring-less resonance mechanism where stiffness is provided by repelled magnetic forces. The
sensitivity is affected only by friction forces inside the mechanism of the harvester. Ways of decreasing friction, it means
an increasing sensitivity, are investigated in this paper. The increasing sensitivity of the harvester provides more
generated energy or decrease of the harvester size and weight.