A Hybrid Single-Phase Transformer-less Solar Photovoltaic Grid-Connected Inverter with Reactive Power Capability and Reduced Leakage Current

This paper proposes a novel hybrid inverter topology for grid-tied photovoltaic (PV) systems that integrates decoupling and mid-point clamping techniques to effectively reduce both the root mean square (RMS) and peak values of leakage current. The approach eliminates the need for a transformer, thereby reducing overall system cost and weight, while addressing the leakage current issues that arise in the absence of galvanic isolation between the PV system and the AC grid. Additionally, the proposed topology supports the injection of both active (P) and reactive (Q) power into the grid, aligning with future grid requirements. The system is simulated using the MATLAB/Simulink environment under both open-loop and closed-loop conditions. Under open-loop operation, the leakage current mitigation capability is demonstrated, while under closed-loop control, model predictive control (MPC) is employed to regulate and inject active and reactive power into the grid.

Keywords: Active power, leakage current, model predictive control, reactive power, total common mode voltage, transformer-less grid-tied inverter.