FRACTIONAL-ORDER PID-BASED CONTROL FOR LEAKAGE CURRENT SUPPRESSION IN SINGLE-PHASE TRANSFORMER-LESS PV INVERTERS

Abstract

This paper presents a FOPID-controlled hybrid transformer-less single-phase grid-connected solar PV inverter designed to reduce leakage current and provide reactive power compensation. The proposed topology combines decoupling and mid-point clamping techniques to suppress RMS and peak leakage currents while enabling independent control of active and reactive power. A Fractional Order PID (FOPID) controller is used to improve dynamic performance, power quality, and robustness. The system is validated through MATLAB/Simulink simulations and experimental results under both open-loop and closed-loop conditions. Comparative analysis shows superior performance in terms of leakage current reduction, control accuracy, and grid support capability compared to existing transformer-less inverter topologies.