Flyback Topolomy Based Grid-Connected Photovoltaic Micro-Inverter

Solar energy is a clean, renewable energy resource; the development of the solar energy can help to alleviate the energy crisis and environment crisis. And it’s a very effective solar use pattern for the photovoltaic (PV) power generation system to convert the solar energy into the high-value product-power. The AC Module (ACM) is a small PV power generation system which connects one PV module to one grid-connected micro-inverter, it’s adaptable, high-efficiency, market-welcomed, and it’s becoming a hot spot in the field of PV power generation system by greater attention.As the micro-inverter (MI) in the ACM is the output of the PV module and the input of the gird, it must do the maximum power point tracking (MPPT) to the PV module and meet standards for utility interface of PV system. The specific requirements of the MI design were sorted out by the article.The Flyback topology based MI has a simple structure, a single-stage power control logic and both make effective cost savings. And also the Flyback topology based MI only has one high-frequency switch link, and can be controlled working in the quasi-resonant mode, and both can raise the overall system efficiency.The working principle of the Flyback topology based MI and the quasi-resonant mode was detailed analyzed.The main power circuit of the MI was designed according to the principles and requirements, and the loss analysis was made with the MATHCAD. The MPPT, phase lock logic (PLL) control algorithm and the protection circuit were designed.MATLAB and PSIM were used to simulate the proposed design and a100W experimental prototype was built. Through the analysis and comparison of the simulation waveforms and experimental waveforms, the validity of the design was fully verified.