Control of a small wind turbine in the high wind speed region

This paper proposes a soft-stalling control strategy for small wind turbines operating in the high and very high wind speed region. The proposed strategy moves the operating point of the machine from the maximum power point trajectory (MPPT) to a decreased efficiency operating point whenever the wind speed excesses the machine torque or the power converter current capability by stalling the wind turbine. The proposed method only uses the voltage and current sensors which typically exist in small wind turbines, the wind speed and the generator speed not being required. The proposed method is applied to a wind turbine using a permanent magnet generator connected to an uncontrolled rectifier, which is controlled using a MPPT strategy. Simulation and experimental results are included to demonstrate the performance of the proposed method.