Improved Virtual Synchronous Generator Control of DFIG under Symmetrical Drop of Grid Voltage

In order to optimize the frequency response characteristics of the wind power generation system, virtual synchronous generator (VSG) control is applied to doubly fed induction generator (DFIG). However, due to the slow dynamic response of original VSG control, rotor side converter cannot generate an appropriate regulated voltage quickly when the grid voltage occurs a symmetrical drop. To solve this problem, this paper proposes an improved control strategy. By introducing the rotor transient current control loop, the attenuation speed of stator transient flux is accelerated. At the same time, transient virtual resistance and SVPWM overmodulation limiting module are used to limit transient overcurrent and modulation overvoltage respectively. The simulation results validate the effectiveness of the proposed control method.