Research on Low Voltage Ride-through Control Strategy of Virtual Synchronous Generator Based on Phase Jump Compensation

Abstract

As one of the grid-forming (GFM) inverter control technologies, the virtual synchronous generator (VSG) plays a huge role in improving the inertia and supporting the voltage of the power grid. The research on the low-voltage ride-through control strategy urgently needs further improving. In the power system, the occurrence and removal of the short-circuit faults may lead to changes in the topology of the power grid, resulting in the voltage amplitude and phase jumps at the VSG grid-connected points. Aiming at this problem, this paper analyzes the influence of the amplitude and phase jumps on the conventional low-penetration control strategies during the faults, and proposes a VSG improved low-penetration strategy based on the amplitude switching and phase compensation. This strategy regulates the inverter port voltage from two perspectives of the amplitude and the phase, which realizes the overcurrent suppression during the low breakdown period and the fast stabilization of the power output. In addition, this paper finds that there is also the problem of voltage phase jumps at the grid connection points during the fault recovery. In order to suppress the overcurrent impact of the inverter caused by the voltage jumps at this time, this paper analyzes the application of the improved VSG low-piercing strategy during the fault recovery period. On this basis, the auxiliary control is further used to realize the smooth exiting of the low penetration control strategy, restoring the normal control state of the VSG. Finally, the effectiveness of the proposed strategy is verified by using the MATLAB/Simulink simulation.