Simulation research of boost-flyback photovoltaic grid-connected micro-inverter

Boost-flyback converter can be regarded as a combination of boost and flyback circuit. The leakage inductance of the transformer serves as the energy inductance of boost converter. In this paper, a new strategy which applies boost-flyback topology to a photovoltaic micro-inverter is proposed. The working principle of boost-flyback is analyzed and a switching average model of boost-flyback is obtained. Compared with the traditional flyback type micro-inverter, boost-flyback is capable of recycling the leakage inductance energy without adding any clamping circuit. Thus, the voltage stress of the main switch is reduced and the system efficiency is improved. Meanwhile, as the steady-state voltage gain is increased, the effective working area of the duty ratio is expanded. To support the theoretical analysis, the feasibility and reliability of the proposed method are verified by simulation results.