Control of PMSG wind turbines based on reduced order resonant controllers under unbalanced grid voltage conditions

The effective control of permanent magnet synchronous generator(PMSG) based wind energy conversion systems(WECS) under unbalanced grid voltages is important to improve the grid-connected operation ability. This paper applies the proportion integral plus reduced order resonant integrator(PI-ROGI) controller to the PMSG grid-side converter, which can achieve zero current error control in the positive synchronous rotating reference frame without any decomposition of positive and negative-sequence currents. The double supply frequency oscillations of DC-link voltage and the output active power caused by the lose control of negative-sequence current can be well restrained. A PI-ROGI based control scheme implemented in the positive synchronous rotating reference is designed. Furthermore, the simulation results using Matlab/simulink demonstrate the effectiveness of the proposed control scheme on improving the operational performance of PMSG under asymmetrical grid faults.