A Single Phase Transformerless CSI Inverter Topology for Minimization of Leakage Current in Grid Integrated PV Systems

This paper presents the design and analysis of a new five-level single-phase transformer-less current source inverter (CSI) topology for the minimization of ground/leakage current in PV grid integration systems. The topology is configured using inductors & high and low-frequency groups of switches. The Pulse Width Modulation (PWM) is applied to a high-frequency group of switches to fulfill the charging & discharging of inductor currents and the low-frequency group of switches is operated to obtain bi-directional current/voltage at the output. The topology is controlled to limit the common-mode voltage (CMV) frequency at line frequency and thereby the leakage currents are shown minimized. The operation of the converter and MATLAB-based simulation results are presented in the work to showcase the merits of the proposed topology in improving the voltage/current profiles in comparison with the existing ones.