Design and Implementation of High-Efficiency Transformerless Solar Inverter with Reduced Leakage Current

Abstract

The rapid growth of grid-connected photovoltaic (PV) systems has increased the demand for compact, high-efficiency, and cost-effective power conversion technologies. Transformerless solar inverters are increasingly used in modern PV systems because they eliminate bulky isolation transformers, resulting in higher efficiency, reduced size, lower cost, and improved power density. However, the absence of galvanic isolation introduces common-mode (CM) leakage current due to parasitic capacitance between the PV array and ground. This leakage current can cause electromagnetic interference (EMI), safety risks, and non-compliance with grid standards, making its reduction an important challenge in transformerless inverter design.This study presents the design, modelling, simulation, and experimental implementation of high-efficiency transformerless solar inverter with reduced leakage current for photovoltaic applications. The research focuses on developing an improved HERIC (Highly Efficient and Reliable Inverter Concept) topology capable of maintaining nearly constant common-mode voltage to suppress leakage current. Mathematical models of the PV array, DC–DC boost converter, and inverter stage were developed, and system performance was evaluated using MATLAB/Simulink simulations. To validate the proposed design, 1 kW laboratory prototype was constructed and experimentally tested. Results show that the inverter achieves efficiency above 98%, THD below 3%, and leakage current within safety limits, demonstrating improved performance for grid-connected PV systems.