An improved current-limiting control strategy of grid-forming inverter during grid fault

Abstract

Due to the increasing penetration of new energy generation based on power electronic devices in the power grid, the characteristics of the power system are changing. As a new and continuously developing concept proposed in recent years, the grid-forming(GFM) inverter can adapt to the grid with high penetration of renewables, especially can provide support for the power grid in the weak grid. In this paper, the synchronous power control(SPC) strategy is adopted , and the behavior of the GFM inverter is analyzed during the fault. To address the overcurrent problem under weak grid, a current-limiting strategy is proposed considering the effect of the power outer loop, which limits the current within the allowable range while maintaining the grid structure in the weak grid, and improves the dynamic response. Finally, a simulation model is built in PLECS to verify and analyze the proposed control strategy.