Active stabilization control strategy for storage system paralleled with constant power loads

Abstract

In DC Microgrid, the majority of the loads are connected to the grid via power electronic converters. These loads act as constant power loads (CPLs) when tightly regulated. If the voltage changes, the CPLs behave negative incremental impedance characteristic during dynamic periods, and could cause system instability. To guarantee the system stability and simultaneously maintain the CPLs good performances, this paper utilizes an active stabilization control strategy for the battery converter paralleled with CPLs. Based on the mixed potential theory, the large signal models of the storage system and the CPLs are established. The control strategy considers the negative incremental impedance of the CPLs in the outer control loop, and consequently, the converter with the proposed strategy could actively and quickly compensate the CPLs during large disturbances. The stability constraint is very simple and easy to be implemented. The simulation results validate the effectiveness of the active stabilization control strategy.