Leakage current reduction of Z-source four-leg inverter for transformerless pvsystem

The leakage current reduction is one of the most important issues for transformerless PV systems. The conventional Z-source three-phase PV inverter failed to suppress the leakage current in an effective way. In order to solve the problem, a new modulation strategy for the Z-Source four-leg transformerless PV inverter is proposed in this paper. The common mode loop model presented firstly. And then the common mode voltage behavior and the effect of factors on the leakage current are discussed. A new modulation strategy is proposed to achieve the constant common mode voltage. Therefore, the leakage current can be suppressed effectively. Finally, the proposed strategy is tested, and the results verify the effectiveness of the proposed solution.