Early solar inverter system output generally installed frequency isolation transformer, to achieve voltage adjustment and electrical isolation, to ensure safe and reliable operation of the system. However, the power frequency isolation transformer bulky, high cost, loss of large, affecting the efficiency of the whole system. If the high-frequency transformer is used to realize the electrical isolation of PV and power grid, the system volume, quality and cost can be reduced, but the system efficiency is not improved obviously. Therefore, the non-isolated grid-connected solar inverter system becomes the hot spot of research. High, small size, low quality and low cost, but the elimination of the transformer makes the PV and the grid between the electrical connection, the leakage current may be greatly increased, resulting in conduction and radiation interference, increase the input current harmonic and loss , And even endanger the safety of equipment and personnel. So the elimination of common mode current has become a non-isolated grid-connected solar inverter can be universal and must cross the obstacles.

In order to solve the above problems, a non-isolated single-phase solar inverter is studied. The topology is not only effective in solving the leakage current problem, but also has the advantages of low on-state loss, high efficiency and strong stability.