Leakage current minimization techniques for single-phase transformerless grid-connected PV inverters — An overview

This paper presents an overview about techniques employed to minimize the leakage current in single-phase transformerless grid-connected PV inverters, using topologies derived from the full-bridge voltage source inverter (VSI). Some representative topologies and common mode (CM) filter implementations are presented. Among the analyzed solutions, a CM filter integrated to the harmonics filter, applied to a conventional full-bridge converter with unipolar output voltage, represents a promising solution, confirmed by simulation and experimental results. Additionally, discussions about safety standards and analysis of leakage current production mechanism are presented.