A high efficiency and reliability single-phase photovoltaic micro-inverter with high magnetics utilization for nonisolated AC-module applications

Photovoltaic (PV) ac module becomes a trend for its great flexibility and high system-level energy harnessing. Non-isolated two-stage PV ac module with non-isolated high boost ratio dc-dc converter and transformerless inverter can be an option for high efficiency design. This paper starts with review of state-of-the-art transformerless inverters, and proposes a novel high efficiency and high reliability transformerlees inverter, which prevents from phase-leg shoot through, eliminates the PWM dead-time, minimizes leakage current, avoids body diode conduction for main devices, and effectively utilizes magnetic components. Modulation method and common mode leakage current issue are then described. Experiment results of a 250W (380Vdc, 240Vac) hardware prototype are shown to demonstrate the merits of proposed transformerless inverter.