Power control and pulsation decoupling in a single-phase grid-connected voltage-source inverter

By means of providing control of reactive power injection/absorption, distributed photovoltaic-based voltage-source inverter can contribute to network voltage stability and works as static var compensation. The voltage-source inverter is general a single-phase grid-connected inverter. The single-phase grid-connected inverter has inherently twice frequency power pulsation that causes the output current distortion and reduces the utility of photovoltaic module. The power pulsation is double the line frequency and no manipulation of switching frequency or converter topology can reduce the energy requirements. Therefore, in this work a power control and power pulsation-decoupling method is proposed by integrated with digital phase-lock-loop, active and reactive power control, and power pulsation decoupling at dc side. Simulation results have demonstrated that this method provides the system with strong active power and reactive power regulation capability, few line current harmonics, and dramatic reduction of current and voltage pulsation at the output of photovoltaic module.