Pulse Width Amplitude Modulation Based Single-Phase Quasi-Z-Source Photovoltaic Inverter with Energy Storage Battery

摘要

The pulse width amplitude modulation (PWAM) was earlier proposed for the single-phase quasi-Z source inverter (qZSI) based photovoltaic (PV) power system to reduce qZS impedance values while improving efficiency. The method resulted in highly fluctuated qZS inductor currents and capacitor voltages as well, which makes it difficult to integrate energy storage battery as a conventional qZSI. This paper proposes an improved topology with energy storage elements for the PWAM-based single-phase qZS PV inverter, maintaining constant battery current. Also, control strategy is disclosed for grid-connected and islanding operation. Simulation and experimental results verify the proposed approach for dual-mode operation of the PWAM-based single-phase qZS PV power system.