Simulation Analysis on Quasi-Single-stage Grid-Connected Photovoltaic Inverter Based on Push-pull Forward Converter

A single-stage grid-connected photovoltaic system was investigated to overcome the drawbacks of two-stage grid-connected photovoltaic system such as complex structure, high cost and low efficiency. It has researched the grid-connected current sinusoidal control, maximum power point tracking (MPPT) and the system stability under the rapidly change of light intensity, which were based on the instantaneous current feedback control, dual mode MPPT and DC-link voltage feed-forward control. At last, the model of 300VA PV grid-connected system was built and simulated to verify the theoretical analysis. The research results demonstrate that the single-stage grid-connected system have many advantages such as high quality and good dynamic characteristics of grid-connected current, accuracy MPPT, high efficiency, strong adaptability to the rapidly change of light intensity, high reliability etc. Therefore, it can be deduced that this kind of PV system has a wide application prospect in the place where the grid-connected inverter requires electrical isolation.