Common mode voltage of three phase split source inverters for solar pumping applications

Low-voltage photovoltaic (PV) systems often employ a cascaded power conversion structure comprising a separate boost converter and inverter, leading to increased complexity and reduced overall efficiency. The split-source inverter (SSI) topology addresses these limitations by combining voltage boosting and inversion functionalities within a single-stage architecture, offering improved integration and reduced component count. This paper proposes a space vector modulation (SVM) strategy for SSIs and compares it against a modified SVM (MSVPWM) approach designed to mitigate high-frequency common-mode voltage (CMV). A detailed analysis is carried out focusing on CMV characteristics, leakage current behavior, and total harmonic distortion (THD) in line-to-line voltages. Experimental and simulation-based comparisons with conventional modulation methods are provided to validate the effectiveness of the MSVPWM approach, demonstrating notable improvements in electromagnetic performance and output waveform quality. In particular, the MSVPWM technique outperforms the conventional SVPWM method, achieving a 7.6% reduction in voltage THD and a 66.7% reduction in CMV. These improvements confirm the suitability of the MSVPWM method for PV powered pumping systems and other applications that demand high power quality.