Research on speed control system for fixed-pitch wind turbine based on disturbance observer

Considering the characteristics of fixed-pitch variable-speed wind turbine operating in all operating wind speed, the small signal model was established, which indicates that the system is unstable in high wind speed. In this paper, the use of disturbance observer for aerodynamic torque estimation and compensation was presented, which is to eliminate the unstable factors in the system itself and make the system into a stable linear system. And then the speed control system was designed based on the RT-LAB real time simulation system. The results show that the fixed-pitch variable speed wind turbines can be operated stably in all operating wind speed and the speed control system have good at tracking changing wind velocity, which indicated that fixed-pitch variable speed wind turbine can be operated not only for MPPT in low wind speed but also for constant power control in high wind speed.