A control strategy for parallel 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 has two instantaneous average values control loops: one for voltage and another for current. The first one controls the output voltage of the inverter while the second is designed to control the parallel operation of the inverters. The proposed parallelism control acts in the voltage before the LC filter and is based in the feedback of the L inductor current. There is no communication among inverters so that one unit is independent from the others. A prototype with 3 inverters of 5 kVA each was built to corroborate the control technique.