Analysis of the conflict between close-loop control and the current-sharing of ac parallel inverters and parallel control strategy

On the basis of the developed mathematic model of one phase inverter, the paper analyzed the conflict between the closed-loop control and the current-sharing of the parallel inverters. The compound control combining open loop with closed loop was presented based on the reference voltage feed-forward to relieve the conflict. The current-sharing control strategy based on interactive-tracking synchronization (ITS) and the adjustment of reference voltage amplitude was proposed, and two parallel-connected inverters controlled by DSP were implemented. The experiments indicate that the good static and dynamic current-sharing performance of the parallel system can be gained by the proposed method and N+1 parallel redundancy can be realized.