A new maximum power point tracking control scheme for wind generation

According to the aerodynamical characteristic of the wind turbine, a maximum power point tracking (MPPT) is necessary to get high efficiency for wind power conversion, which means that the rotating speed of wind turbine should be adjusted in the real time to capture maximum wind power. Because of the fast variation of wind speed and the heavy inertia of generator, the MPPT control of wind generation is much challengeable. A new MPPT control scheme has been developed for permanent magnetic (PM) generator driven by a three-phase inverter to generate 350 V direct current power to the DC bus line. The main differences between the method used in the proposed MPPT system and other techniques used in the past are as follows: (1) the tracking step is variable according to the change of wind speed; (2) in order to avoid the dead time effect of the inverter the MPPT control is synchronized to the rotating speed of the generator; (3) a low pass filter is used at the output of the MPPT controller to decrease the fluctuation of the rotating speed reference. The resulting system has high-efficiency, lower-cost and fast, stable tracking speed. The experimental results show that it can track as fast as 0.2Hz variation of wind speed and increases the output wind power as much as 48%. As a result, the efficiency of the generation has been improved evidently.