Leakage Current Mitigation in Transformerless Z-Source/Quasi-Z-Source PV Inverters: An Overview

The Z-Source Inverter (ZSI) and quasi-Z-Source Inverter (qZSI) are single-stage configurations with high boosting ratios. They might be promising solutions for transformerless PV systems, requiring a high-step voltage conversion. The lack of galvanic isolation becomes the new challenge. High common mode voltages (CMV) may appear and thus potentially induce electrical hazards. To address this issue, topological and modulation strategies have been extensively discussed in the literature. However, it still lacks a general benchmark. In this paper, prior-art solutions for leakage currents mitigation in ZSI/qZSI-fed PV systems are reviewed. It serves to initiate further research to advance the performance of transformerless ZSI/qZSI-fed PV systems.