In this paper, a research for the effectiveness enhancement of a Cycloidal Wind Turbine by individual active control of
blade motion is described. To improve the performance of the power generation system, which consists of several
straight blades rotating about axis in parallel direction, the cycloidal blade system and the individual active blade control
method are adopted. It has advantages comparing with horizontal axis wind turbine or conventional vertical axis wind
turbine because it maintains optimal blade pitch angles according to wind speed, wind direction and rotor rotating speed
to produce high electric power at any conditions. It can do self-starting and shows good efficiency at low wind speed and
complex wind condition. Optimal blade pitch angle paths are obtained through CFD analysis according to rotor rotating
speed and wind speed. The individual rotor blade control system consists of sensors, actuators and microcontroller. To
realize the actuating device, servo motors are installed to each rotor blade. Actuating speed and actuating force are
calculated to compare with the capacities of servo motor, and some delays of blade pitch angles are corrected
experimentally. Performance experiment is carried out by the wind blowing equipment and Labview system, and the
rotor rotates from 50 to 100 rpm according to the electric load. From this research, it is concluded that developing new
vertical axis wind turbine, Cycloidal Wind Turbine which is adopting individual active blade pitch control method can be
a good model for small wind turbine in urban environment.
In this paper, a research for the performance improvement of the straight-bladed vertical axis wind turbine is described.
To improve the performance of the power generation system, which consists of several blades rotating about axis in
parallel direction, the cycloidal blade system and the individual active blade control system are adopted, respectively.
Both methods are variable pitch system. For cycloidal wind turbine, aerodynamic analysis is carried out by changing
pitch angle and phase angle based on the cycloidal motion according to the change of wind speed and wind direction,
and control mechanism using the cycloidal blade system is realized for 1kw class wind turbine. By this method, electrical
power is generated about 30% higher than wind turbine using fixed pitch angle method. And for more efficient wind
turbine, individual pitch angle control of each blade is studied. By maximizing the tangential force in each rotating blade
at the specific rotating position, optimal pitch angle variation is obtained. And several airfoil shapes of NACA 4-digit
and NACA 6-series are studied. Aerodynamic analysis shows performance improvement of 60%. To realize this motion,
sensing and actuating system is designed.
In this paper, the electromechanical displacements of curved piezoelectric actuators with laminated composite material are calculated using high performance computing technology, and the optimal configuration of composite curved actuator is proposed. To predict the pre-stress in the device due to the mismatch in coefficients of thermal expansion, carbon-epoxy and glass-epoxy as well as PZT ceramic are numerically modeled by using hexahedral solid elements. Because the modeling of these thin layers causes the numbers of degree of freedom to increase, large-scale structural analyses are performed through the PEGASUS supercomputer which is composed of 400 Intel Xeon CPUs. In the first stage, the curved shape of the actuator and the internal stress in each layer are obtained by the cured curvature analysis. Subsequently, the displacement due to the piezoelectric force by an applied voltage is also calculated and the performance of composite curved actuator is investigated by comparing the displacements according to the configuration of the actuator. To consider the finite deformation in the first stage and include the pre-stress in each layer in the second analysis stage, nonlinear finite element analyses will be carried out. The thickness and the elastic constants of laminated composite are chosen as design factors.