A Current Decoupling Parallel Control Strategy of Single-Phase Inverter With Voltage and Current Dual Closed-Loop Feedback

The output characteristics of a single-phase inverter with voltage and current dual closed-loop feedback control are analyzed, and the equivalent circuit model of a parallel single-phase inverter system is introduced. By taking both resistance and inductance components of the equivalent output impedance into consideration, a current decoupling control strategy of the parallel inverter system is then proposed. Furthermore, by constructing a three-phase balanced current according to the output current of the single-phase inverter, an active and reactive current decomposition method is presented to decompose the output current of the single-phase inverter into active and reactive currents according to the instantaneous reactive power theory. The block diagram of the active and reactive current decomposition method is given, and current decomposition simulation results are shown to verify the analysis results. The prototype is developed, and the control of two parallel-connected 2-kVA inverters is realized. The experimental results show its feasibility and effectiveness.