Performance Analysis of Various Three‐Phase Hybrid Transformerless Inverter Configurations

Three-phase transformerless inverter configurations are widely used in solar photovoltaic (PV) systems due to their high-efficiency power transfer capabilities to the grid. However, the main issue in transformerless grid-connected inverters is the suppression of leakage current (LC), which arises from parasitic capacitances and is worsened by the absence of galvanic isolation. To reduce the LC with the grid standards, we need to maintain the constant common-mode voltage (CMV). Additionally, this poses a challenge to the reactive power injection capability of these inverters under varying grid voltage and power factor conditions. Various transformerless configurations have been established, utilising advanced modulation techniques to address LC suppression and CMV stabilisation. However, these designs often exhibit significant switching losses and inconsistent reactive power performance, limiting their efficiency and reliability in practical applications. To overcome these limitations, hybrid inverter topologies have been approached with modified discontinuous pulse width modulation (MDPWM) techniques. In this research, theoretical modelling and simulation studies are performed using MATLAB/Simulink to evaluate the performance of different hybrid transformerless configurations with proposed MDPWM in reducing switching losses, ensuring CMV stability, minimising device stress and enhancing reactive power handling in PV-fed systems. Additionally, the most effective topology is identified and validated through experimental analysis, demonstrating its superior performance with reduced LC and less variation in CMV.