A Novel Hexagonal Switched Capacitor Unit (HSCU) Design With Seven-Level Multilevel Inverter Topology

In this paper, a new switched capacitor (SC) unit is proposed, which provides a solution for the multiple DC voltage requirement of multi-level inverters (MLIs). The proposed hexagonal switched capacitor unit (HSCU) contains SCs that have self-balancing ability and do not require any additional circuits. HSCU provides three voltage boosts using only one DC voltage source with four power switches, two capacitors, and two discrete diodes. A comparison with related topologies in the literature indicates that the proposed topology requires considerably fewer power devices than others. To suppress impulsive charging currents in the capacitors, a soft charging cell (SCC) is utilized. Experimental results demonstrate that the SCC effectively suppresses current peaks, contributing to improved circuit performance. In addition, the proposed 7L SC-MLI has successfully passed the simulation and experimental realization tests with nearest level control (NLC) modulation techniques and sinusoidal pulse width modulation (SPWM) modulation techniques. Response to dynamic changes in frequency, modulation index (MI) and load have been verified through tests. Power loss analysis was performed in PLECS software, and the efficiency was found to be 96.45%.