Design Method of Control Parameters for PCS Grid-Connected Mode Based on the Stability Analysis of Islanding Switching

In Power Conversion System (PCS), the transition between Grid-Connected Mode(GCM) and Stand-Alone Mode(SAM) has attracted wide attention. However, the traditional PCS with parameters designed according to the grid-connection requirements may have the problem of current oscillation and the protection of the converter when the Grid-Disconnected Mode(GDM) occurs. In this paper, aiming to avoid the high-frequency oscillation of inductor current during GDM, a control parameter design method based on the stability of PCS in GDM is proposed. The mechanism of the oscillation is discussed in detail. Based on the analysis, the proposed design method is further introduced. Finally, the design parameter is verified on a 1 00 -kW three-phase grid-connected T-type inverter.