A control strategy by instantaneous average values for parallel operation of single phase voltage source inverters based in the inductor current feedback

This paper presents a simple, effective and robust control strategy applied to parallel connected of single phase voltage source inverters. The parallelism control is only done using internal measures of each inverter. The objective is to obtain a control system where the inverters are independent from each other. The proposed control strategy of each inverter has two control loops by instantaneous average values: one for voltage and another for current. The first one is designed to control the output voltage of the inverter, while the second is designed to lead the parallel operation of the inverters. The parallelism control acts in the voltage before the LC filter and it is based on the feedback of the L inductor current. Its function is to guarantee the correct load current sharing. The control technique was corroborated through experimental results with a maximum load of 10 kVA supplied by three parallel connected inverters.