Power control strategies of variable speed and variable pitch wind turbines

According to the feature of operation range of variable speed and variable pitch wind turbines, a power control strategy for them is proposed. Utilizing C++ language, the secondary development of the professional design software Bladed for wind turbines as the tool is performed to design the external controller of Bladed; the designed external controller exchanges data with Bladed to control the power output of wind turbine and optimize the performance of wind turbine. Simulation results show that under the wind speed lower than its rated value the external controller can trace maximum power of wind turbine; under the wind speed higher than its rated value the external controller can make the amplitude of power output less than that controlled by internal controller and stabilize the power output near its rated value; during the course of full load optimal control, according to the variation of wind speed the external controller can rapidly regulate the wind turbine to implement smooth transition of control process. Thus the proposed external controller possesses a better performance and the correctness and feasibility of the proposed power control strategy are varied.