A deadbeat control method for circulating current between parallel-connected inverters

Circulating current restraining is the key technology for the reliable operation of parallel-connected inverters. This paper proposes a deadbeat zero-sequence circulating current control method based on the compensation principle of zero-sequence voltage difference, which is presented for the parallel operation of redundant grid-connected inverters with common dc bus in microgrid. Firstly, the equivalent circuit model of circulating current between parallel inverters is analyzed, the compensation quantity of zero-sequence voltage difference between inverters is obtained by the deadbeat current control method according to the zero-sequence current feedback of a single inverter and. Then, the zero-sequence voltage difference between parallel inverters is close to zero for restraining the zero-sequence current by adjusting the zero-sequence voltage of a single inverter. Finally, simulation and experiment results verified the validity of the proposed control method for zero-sequence circulating current between parallel inverters.