Power Control of BDFRG Variable-Speed Wind Turbine System Covering All Wind Velocity Ranges

In this paper, a power control strategy for the brushless doubly fed reluctance generator (BDFRG) based variable-speed wind turbine system is proposed. The proposed control strategy covers all system operational regions including: maximum power point tracking (MPPT) region, constant speed region, and constant power region; whereas, the studies in the literature for the BDFRG wind turbine system are only limited to the MPPT region. For capturing maximum power from the wind in the MPPT region, a turbine power feedback based MPPT, which is a method with fast dynamic response, is used. In the constant speed region, the BDFRG speed is kept constant, and for high wind velocities in constant power region, the controller decreases the BDFRG speed to prevent the increase of the turbine power more than its rated value. In addition, a turbine power observer is proposed to obtain turbine power. The BDFRG wind turbine system model based their dynamic equations, which explained in the paper, is simulated in MATLAB/Simulink software and the performance of the proposed control strategy is studied. The simulation results verify the effectiveness of the proposed control strategy in all three operational regions as well as the acceptable performance of the turbine power observer.