Low voltage ride-through control strategy for a wind turbine with permanent magnet synchronous generator based on operating simultaneously of rotor energy storage and a discharging resistance

Abstract

When the low voltage ride-through(LVRT) method of combining rotor energy storage with a discharging resistance for a wind turbine with permanent magnet synchronous generator(PMSG) is adopted, with the traditional control strategy, there are the shortcomings of the rotor energy storage function not exerted to the maximum extent and the large discharging current flowing through the discharging resistance. On the above shortcomings, a LVRT control strategy for a wind turbine with PMSG based on operating simultaneously of rotor energy storage and a discharging resistance is presented. On the basis of the rotor motion equation, the setting calculation formula of the active power of machine-side converter for maximizing the performance of the rotor energy storage is derived, and the switching method of the discharging resistance is designed. Simulation examples of a wind turbine with PMSG rating of 1.5MW are constructed using PSCAD/EMTDC to compare the proposed LVRT control strategy with the traditional control strategy according to the LVRT requirements of China National Standard for a wind turbine generator system. The simulation results show that the proposed LVRT strategy can not only exert the rotor energy storage function to the maximum extent, but also significantly reduce the discharging current, which verifies the effectiveness of the proposed LVRT control strategy.