Innovative Transformerless Single-Phase Inverter for Minimizing Leakage Current and Enhancing Reactive Power in Grid-Tied PV Systems

Abstract Transformerless inverters are rapidly gaining popularity in small-scale grid-connected PV systems due to their compact size, cost-effectiveness, and superior efficiency compared to traditional inverters. However, leakage current caused by the stray capacitance between the direct current (DC) and alternating current (AC) circuits remains a challenge. To address this issue, various techniques such as using low leakage capacitors and adding inductors to the circuit have been developed. The inverter topology proposed in this paper changes DC power from solar panels into AC power and supplies it directly to the grid. Additionally, it keeps grid voltage and current total harmonic distortions (THDs) below 1%, reduces leakage current to nearly zero, and significantly improves power quality and reactive power. Moreover, with a consistent common-mode voltage, the leakage current has been effectively reduced to 1.084 mA. In the proposed configuration, there are five insulated gate bipolar transistors (IGBTs) and one reverse blocking insulated gate bipolar transistor (RBIGBT) utilized alongside an LCL filter. Also, the efficiency value has reached 99.77% in simulation phase, and it shows 98.16% in laboratory phase, which are an incredible value for this structure. The paper concludes that the proposed transformerless inverter offers a promising solution to address the challenges faced by photovoltaic (PV) systems while maintaining high efficiency and low cost. The validity of this topology has been confirmed through both MATLAB/Simulink simulations and physical implementation in the laboratory, with the simulation results aligning with the real-world performance.