Parallel control strategy of single-phase voltage-source inverter base on synchronous signal bus

Conventional droop-control strategy of parallel inverter regulates the phase and the amplitude of the output voltage according to output active power and reactive power respectively. But for a two-loop feedback control voltage-source inverter, active power and reactive power are related to both the amplitude and the phase of the output voltage. In this paper, the equivalent output impedance of the inverter is derived and the quantitative relationship between active/reactive power and amplitude/phase of output voltage is discussed. Based on which, a parallel inverter control strategy is proposed, with the phase synchronization via bus and output voltage amplitude regulated by the relation of output active power and reactive power. Based on this control technique, the model of parallel inverter system is established. Experimental results show the effectiveness of the control strategy.