Implementation of filter-clamped topology for transformerless three-phase PV inverters with reduced leakage current

Abstract

The growing prevalence of grid-connected photovoltaic (PV) systems has intensified the demand for efficient, reliable, and compact power conversion technologies. Transformerless photovoltaic (TLPV) systems provide improved efficiency and reduced size and costs compared to those using line-frequency or high-frequency isolation transformers. However, these inverters commonly exhibit leakage current because they lack galvanic isolation. Conventional topologies address this issue by adding extra semiconductor devices or employing complex control methods. This paper examines how a filter-clamped inverter (FCI) operates in grid-connected three-phase transformerless photovoltaic (TLPV) applications. However, the proposed inverter successfully reduces leakage current without additional components or control modifications. This makes it a compact and simplified alternative for transformerless PV applications. Additionally, the traditional full-bridge (FB) inverter with three phases, when compared to the FC inverter, has very high leakage current. Simulation results validate the FC inverter’s ability to minimize leakage current.