Novel Design for Variable Pitch Control System and Constant Rotational Speed Control of Rotor for a Small Wind Turbine

Most of the small wind turbines are designed with no control or passive control due to the cost consideration so that the electric generation performance is limited as the wind speed is over the rated wind speed. Thus, the objective of the paper is to improve the electric generation performance by developing a novel active pitch control system and a rotor constant rotational speed control for a 2kW small wind turbine. The study first developed a novel mechanism design for the active-controlled pitch control system. The novel mechanism is the DC servo motor-driving variable-pitch bevel mechanism. By using the PID controller, the one to three bevel gear chain driven by DC servo motor is applied to adjust the pitch angles of the three blades at the same time. Then, the dynamic simulation of the overall system of wind turbine was developed by combining softwares of FAST, ADAMS and MATLAB. After that, the proposed novel mechanism design of the active pitch control and the constant rotational speed control of rotor could be verified via dynamic simulation. For that, the controllers of pitch control and the constant rotor constant rotational speed control were developed by PID control and fuzzy sliding mode control. The experimental prototype system was modified according to the TECO 2kW small wind turbine which original type has no control. The novel mechanism for the active pitch control system and the required controller system were integrated and tested in the open wind tunnel. When the wind speed is above the rated wind speed, the DC servo motor-driving variable-pitch control system starts to work to regulate the pitch angle to keep the constant rotational speed of rotor. The one to three bevel gear chain driven by DC servo motor is applied to adjust the pitch angles of the three blades at the same time. Through the active pitch control system, the constant rotational speed control of rotor can be implemented.