T-Type Seven-Level Inverter With Triple Voltage-Boosting Gain

Switched-capacitor (SC)-based multilevel inverters (MLIs) have drawn significant attention owing to their ability of voltage boosting and self-voltage balancing. However, these topologies suffer from impulse charging current due to the paralleling of SCs with dc source, which is essential for achieving voltage boosting. On this line, a seven-level (7L) SC-based inverter to combat the issue of SC impulse charging current while preserving the beneficial features of conventional SC-MLIs is presented. Structurally, the devised topology integrates a half-bridge module and an inductor to achieve the capacitor soft charging. The usage of commercially available half-bridge intelligent power modules as a basic building block for the developed inverter structure makes it highly modular. The capacitor and the input dc source are connected in series to achieve a voltage gain of three. The operation of the proposed topology is detailed and verified through extensive simulation and experimentation. The obtained results, confirming the practical viability of the proposed topology, are presented. Finally, an exhaustive and comprehensive comparison with other SC-MLIs is included to highlight the merits of the proposed topology.