Current source inverter with reduced leakage current for transformer-less Grid -PV interface

Abstract

A single-phase, single-stage current source inverter (CSI) suitable for transformer-less grid-PV interface is proposed in this paper. A split capacitor arrangement and a common mode choke are used to modify the conventional CSI structure, to reduce the leakage current. Higher reliability and voltage boosting capability of the CSI are the main advantages compared to the voltage source inverter (VSI). A cost effective and computationally less intensive control method based on the sinusoidal pulse width modulation (SPWM) technique is suggested to improve the quality of the grid current. Design and analysis of the proposed CSI structure and the modified control technique is discussed in detail. Reduced leakage current and high quality injected grid current, with a relatively low value of inductor is obtained with the suggested modification. Simulation results validate the effectiveness of the proposed CSI with the proposed modification in the SPWM technique.