A Novel Transformerless Topology for Grid-Connected Photovoltaic Inverters with Mitigated Common-Mode Current

Abstract:
Leakage current is a critical concern in transformerless grid-connected photovoltaic (PV) inverters, as it can introduce electromagnetic interference, compromise safety, and deteriorate power quality. This paper proposes a novel singlephase transformerless inverter topology designed to suppress leakage current by maintaining an almost constant commonmode voltage within standardized safety limits. The system is modeled and validated through control hardware-in-the-loop (C-HIL) testing, where the plant model serves as a digital twin and the embedded controller is implemented on a Texas Instruments F28335 DSP. Experimental results confirm that the proposed topology mitigates leakage current and reduces total harmonic distortion (THD) and enhances energy conversion efficiency, outperforming conventional transformerless inverter configurations.