Analysis of recent developments in three-phase transformerless inverter topologies for photovoltaic and electric vehicle applications

At present, transformerless photovoltaic inverter topologies (TLPVIT) are more popular due to their high-class feature in terms of size, weight, and efficiency, respectively. However, the analysis of many interesting single-phase transformerless photovoltaic inverter configurations (TPVIC) with galvanic isolation and common-mode voltage clamping (CMV) methods has been investigated and concluded that CMV clamping topologies have excellent features compared to galvanic isolation in the form of CMV and CM-leakage current. The main aim of this chapter is to compare and analyze various three-phase transformerless inverter configurations with and without clamping techniques and their impact on CM-voltage as well as CM-leakage current suppression. In addition, a simple modified clamping three-phase transformerless inverter structure and corresponding pulse-width modulation is proposed based on a conventional three-phase inverter. The performance analysis of the discussed topologies, including the new one, in the form of CMV, leakage current, total harmonic distortion (%THD), and switching count is validated through simulation results. All findings clearly indicate that three-phase clamping topologies have relatively better performance in the form of CMV and CM-leakage current than single-phase galvanic isolation systems.