Control strategy of VSC applied in PMSG-based wind power generation considering three-phase unbalance and harmonics

Power quality problem has become a major concern within power society as an increasing number of VSC applied in PMSG-based wind power generation. The three-phase unbalance and harmonics can cause unrecoverable damage to VSC and thus bring about great economic loss. To reduce the negative impact of three-phase unbalance and harmonics, a new control method for VSC-based converters is proposed in the paper. Firstly, in order to set off the negative sequence current of the VSC, a novel control strategy based on negative sequence voltage compensation has been proposed in this paper. Secondly, in order to suppress harmonics, Proportional-Integral (PI) and Proportional-Resonant (PR) cascade controller has been proposed in this paper. Finally the proposed approach is tested by MATLAB/Simulink program. Simulation results reveal that the proposed method can effectively compensate negative sequence current and localize the designated harmonic and thus improve the stability and reliability of VSC.