微网中光伏逆变器并联系统稳定性分析

small-signal model for photovoltaic parallel inverters system in microgrid based on droop method was proposed in this paper, and a method to design droop coefficients was put forward. Depending on this small-signal model a wireless-parallel system containing two 1KVA photovoltaic inverters was established. The root locus plots of the system were provided by the software of Matlab. Influences of the coefficients'variation on the stability and dynamic response were studied. As a result, appropriate droop coefficients were selected to restrain circulating current of the system well and make the system operate stably. Both simulating and experimental results verified the correctness and feasibility of the small-signal model and the coefficient design method.