An Improved Efficiency of Single Phase Transformer Less PV Inverter Topology by NPC System

This paper an improved efficiency of single phase transformer less PV inverter topology by neutral point clamping system proposes how to improve the efficiency of single phase PV inverter topology without using of transformer. If we use a photovoltaic inverter connected to direct loads through transformer the efficiency is largely decreased due to the power losses and the line transformer is large, heavy and expensive. There is a strong trend in the photovoltaic inverter technology to use transformer less topologies in order to acquire higher efficiencies combining with very low ground leakage current. In this paper, a new topology, based on the H-bridge designed with IGBTs midpoint grounding by sequence diode switching is proposed (NPC). In this topology without use ac bypass circuit consisting of a diode rectifier and a switch with clamping to the dc midpoint we can achieve the improvement in efficiency while conversion and low leakage current. The topology is simulated and experimentally validated, and a comparison with other existing topologies is performed. High conversion efficiency and low leakage current are verified. The proposed topology is verified using MATLAB and the all results are validated.