A Hybrid-Modulated Switched-Capacitor Multilevel Inverter with Zero-Voltage Switching for Reduced Switching Losses

Switched-capacitor multilevel inverters (SCMLIs) are widely adopted for their compact design and voltage-boosting capabilities. However, conventional SCMLIs suffer from hard-switching operation, leading to excessive switching losses, reduced efficiency, and electromagnetic interference (EMI), especially at high frequencies. To overcome these limitations, this paper proposes a soft-switching SCMLI topology that integrates zero-voltage switching (ZVS) for all switches and zero-current switching (ZCS) for the diodes. The design requires only a single inductor per switched-capacitor (SC) unit, ensuring minimal added complexity. A hybrid modulation strategy is further introduced to minimize switching losses in the H-bridge. Unlike resonant DC/DC converters, the SCMLI's ZVS implementation faces unique challenges due to the wide duty-cycle variations; this work provides a detailed mathematical analysis of resonant states to guide parameter design. Finally, simulation results from a five-level prototype validate the feasibility and performance of the proposed approach, demonstrating significant efficiency improvements over hard-switched counterparts.