Design of a FOPID-Based Hybrid Transformer less PV Inverter with Reactive Power Compensation and Leakage Current Suppression

Abstract

This paper proposes a hybrid transformerless single-phase grid-connected photovoltaic (PV) inverter controlled using a Fractional Order Proportional–Integral–Derivative (FOPID) strategy to enhance system performance and power quality. Transformerless inverters, while efficient and compact, often suffer from issues such as leakage current and limited capability for reactive power support. To address these challenges, the proposed topology integrates mid-point clamping and decoupling techniques to stabilize the common-mode voltage, thereby effectively minimizing leakage current. The incorporation of the FOPID controller significantly improves dynamic performance, robustness, and tracking accuracy under varying environmental and load conditions, including fluctuations in solar irradiance and grid disturbances. The system also enables independent control of active and reactive power, facilitating reactive power compensation and contributing to grid voltage stability. Simulation studies conducted in MATLAB/Simulink demonstrate that the proposed system achieves superior performance in terms of reduced total harmonic distortion (THD), improved waveform quality, and faster transient response compared to conventional control approaches. Additionally, the design ensures compliance with grid standards while maintaining high efficiency and operational safety. Overall, the proposed inverter configuration presents a reliable, efficient, and compact solution for modern grid-connected PV systems, making it a suitable candidate for next-generation renewable energy integration.