Hybrid Multicarrier Modulation in a Multilevel Inverter for Photovoltaic Systems

Abstract

This work proposes a hybrid multicarrier pulse width modulation (H-MCPWM) technique to reduce leakage current in a Transformer less cascaded multilevel inverter for photovoltaic (PV) systems. The transformer less PV inverter topology has the advantages of simple structure, low weight and provides higher efficiency. However, the topology makes a path for leakage current to flow through parasitic capacitance formed between the PV module and the ground. A modulation technique has significant impact to reduce the leakage current without adding any extra component. The proposed H-MCPWM technique ensures low leakage current in the transformer less PV inverter system with simplicity in implementation of the modulation technique using lesser number of carriers. Experimental prototype developed in the laboratory demonstrates the performance of the proposed modulation technique in reducing the leakage current.