基于无功电流控制的VSG低电压穿越策略OA

The existing closed-loop low-voltage ride-through(LVRT)strategies for a virtual synchronous generator(VSG),which quantitatively regulate active and reactive currents while preserving voltage source characteristics,require mea-surements of both the grid-connected point voltage and grid voltage.To address this issue,a novel VSG LVRT control strategy based on reactive current feedback is proposed in this paper.Under this strategy,the voltage amplitude at the grid-connected point is discretized into multiple levels based on predefined voltage intervals.Upon a grid voltage sag,a dynamic target command voltage is generated by combining the real-time detected voltage level at the grid-connected point with reactive current deviations.To optimize the transient response characteristics,a variable-weight moving aver-age filter is employed for dynamic filtering of the command voltage.In addition,parameter design is achieved by estab-lishing a correlation model between the weighting coefficients and the system's transient characteristics.Furthermore,when the reactive current approaches a preset threshold,the variable-weight moving average filter is configured to ex-hibit proportional-integral(PI)characteristics,enabling precise and steady-state-error-free regulation of reactive cur-rent.Finally,simulation results validate the correctness of the theoretical analysis and the effectiveness of the proposed method.