计及直流动态的构网型VSC暂态稳定机理分析及改进方法研究OA

For the transient stability issue of grid-forming voltage source converters(GFM-VSC),most existing studies have assumed constant DC-side voltage,neglecting the influence of DC-side dynamics on the transient stability of GFM-VSCs,leading to overly optimistic analysis results.Therefore,this paper investigates a GFM-VSC grid-connected system considering DC-side dynamics,revealing a novel transient instability mechanism dominated by DC voltage dynamics and proposing corresponding stabilization methods.Firstly,a large-disturbance analysis model of the GFM-VSC grid-connected system,incorporating energy storage batteries and DC capacitor dynamics,is developed.Then,using equal-area criterion and phase-plane analysis,the transient stability mechanisms of the GFM-VSC under both unconstrained and constrained DC-side energy conditions are revealed.Subsequently,the impact of key factors such as energy storage battery capacity,DC bus capacitance,and current limiting components on the system's transient stability is analyzed,with corresponding stabilization methods proposed.Finally,electromagnetic transient simulations are conducted to verify the correctness and effectiveness of the proposed mechanism analysis and stabilization methods.