Leakage current suppression in virtual DC bus inverter using improved auxiliary circuit

Transformerless photovoltaic inverter is characterized by low loss and high efficiency features. But the topology is burdened with leakage current generation problem. In order to minimize the problem, virtual DC bus concept inverter could be a good solution which is proposed in the literature. But some problem still exists with this inverter. Although it suppresses the leakage current through PV panel to ground capacitor but it cannot eliminate the leakage current through one of the inverter phase to ground capacitor. A very conventional LCL filter is used in previous literature to solve the problem but they all offers substantial amount of leakage current in the system. In order to minimize this problem, we have proposed different designed auxiliary circuit for virtual DC bus inverter. The proposed circuit can suppress the leakage current comprehensively and improve the output voltage quality of the inverter. To verify the advantage of the proposed circuit, simulations are carried out which demonstrates a very promising result.