PV Fed Transformerless Inverter Topology For Leakage Current Reduction

Abstract

In a transformer less inverter grid coupled PV system, a leakage current passes from the parasitic capacitance because of grounding. It may harm the human body and the whole system. Therefore, leakage current reduction is necessary in the case of transformer less type PV systems. The fluctuating common-mode voltage, parasitic capacitance mainly contributes to the circulation of leakage current. By making the common-mode voltage constant, leakage current can be minimized. This article focuses on the reduction of this current leakage. A new topology has been presented in this article. The proposed topology has a clamping circuit of 4 switches and 2 diodes which ensure that during the positive and negative freewheeling the phase voltages must equal to 50% of the dc voltage to give unchanged common-mode voltage and little leakage current. The operating principle is addressed in brief and then the theoretical analysis is confirmed by simulation.