A control strategy for parallel operation of single phase voltage source inverters

This paper presents a simple, effective and robust control strategy applied to parallel connected single phase voltage source inverters. The proposed control strategy has two control loops with instantaneous average values: one for voltage and another for current. The first one controls the output voltage of the inverter while the second controller is designed to lead the parallel operation of the inverters. The intended parallelism control acts in the voltage before the LC filter and it is based on the feedback of the L inductor current. Its objective is to guarantee the correct load current sharing. The inverters are independent of each other and there is no communication among them. A prototype with three 5 kVA inverters each was built to corroborate the control technique.