基于稳定流形法的构网型逆变器暂态稳定性分析

Analysis of the Transient Stability of Grid-forming Inverters Based on Stable Manifold Method

具有电流限幅环节的构网型逆变器在实际运行中,会出现类似于同步发电机功角失步的暂态稳定性问题。为了正确地判断构网型逆变器在大扰动故障下是否发生暂态失稳,需要使用准确的暂态稳定边界。因此,针对构网型逆变器单机并网系统,提出了一种基于稳定流形法的暂态稳定边界描述方法,建立了包含功角与角频率信息的稳定区域,旨在准确地判断具有电流限幅环节的构网型逆变器在电网电压发生大幅扰动后是否失稳,并将该稳定边界应用于分析系统参数对暂态稳定性的影响,同时给出对应的临界切除时间。最后,通过单级式逆变器实验平台验证了暂态稳定边界的准确性和理论分析的正确性。

Grid-forming inverters with current limitation may experience transient stability issues similar to synchronous generator power angle loss during the operation.Accurate transient stability boundaries need to be used to determine whether the grid-forming inverter experiences transient instability under large disturbance faults.Therefore,this paper proposes a transient stability boundary description method based on the stable manifold method for a grid-forming invert-er connected to the grid,and establishes a stable region containing power angle and angular frequency information.The aim is to accurately determine whether the grid-forming inverter with current limitation is unstable after significant volt-age disturbances,and to apply this stability boundary to analyze the influence of system parameters on transient stability,providing the relevant critical clearing time.Finally,the accuracy of transient stability boundaries and the correctness of theoretical analysis are verified through a single-stage inverter experimental platform.