Adding virtual resistance in source side converters for stabilization of cascaded connected two stage converter systems with constant power loads in DC microgrids

In DC microgrids, the operation of the constant power load (CPL) and its associated input filter is very likely poorly damped if no damping method is applied. Active damping methods can significantly improve the power efficiency comparing with the passive damping methods. This paper proposes an active damping method which builds a virtual resistance in the source side converter, and it can effectively stabilize the DC microgrids with CPLs. The advantage of this active damping method is that the stabilization effect is from the source side converters, and therefore, there is no need to sacrifice the transient performance of the CPL. Simulation and experimental results are reported to verify the effectiveness of the proposed idea. © 2014 IEEE