A Three Phase Switched-Capacitor Based Boost Ten-Switch Inverter for Common Mode Voltage Reduction

This paper proposes a three-phase ten-switch inverter topology integrating a switched-capacitor voltage doubler to achieve both voltage boosting and effective common-mode voltage (CMV) reduction. Unlike conventional three-phase inverters, which suffer from limited voltage gain and large CMV fluctuations leading to increased leakage current and electromagnetic interference, the proposed configuration introduces a voltage-doubling stage that boosts the DC-link voltage to twice the input level while maintaining inherent capacitor voltage self-balancing without additional sensors or complex control. The ten-switch structure provides flexible switching control that actively suppresses DC-link voltage fluctuations and significantly reduces CMV amplitude. A dedicated space vector pulse width modulation strategy employing a single zero vector, combined with a logic-based switching function, is developed to confine CMV variation within a narrow range of 1/6 to 1/3 of the DC-link voltage. By constraining CMV fluctuation, leakage current is reduced, thereby improving operational safety in transformerless systems, while the voltage stress across power semiconductor devices remains inherently limited. Comprehensive theoretical analysis, detailed operational principles, PSIM simulations, and experimental validations confirm effective CMV suppression, good conversion efficiency, balanced capacitor voltages, and practical feasibility, demonstrating that the proposed inverter is a promising and cost-effective solution for high-performance photovoltaic and motor-drive applications.