Transformer-less Common-Ground Inverter With Reduced Components

Abstract

This paper a proposes a five-level transformer-less inverter based on common-ground-type topology is presented. In the common-ground-type utility neutral is directly tied with negative terminal of dc source, leads to the short-circuiting of PV-to-ground parasitic capacitance. Hence it solves variable common mode voltage and leakage current issues. Additionally, this topology has the inherent voltage boosting ability based on the principle of switched/auxiliary capacitor. A simplified logic gate-based PWM strategy and control algorithm is developed to maintain the voltage across auxiliary capacitor. A laboratory prototype is developed which proves the feasibility and merits of proposed inverter topology are presented.