The Research on the Zero Sequence Circulating Current Suppression in Parallel Inverters

That inverters work in direct parallel would increase the reliability and capacity, and also reduce the cost and volume for tidal current generation system, but the zero sequence circulating current will be generated. The state model of the parallel connected inverters is constructed in synchronous rotating coordinates, the mechanism of circulating current is analyzed based on the state model, and a zero sequence circulating current suppression method is proposed. The zero sequence voltages of the inverters are regulated in real time to suppress the circulating current. The model of zero sequence circulating current closed-loop control is constructed, and the constraint of the method is analyzed. The experiment results show that the circulating current is suppressed effectively.