Switched Capacitor Based Cascaded Half-Bridge Multilevel Inverter With Voltage Boosting Feature

Abstract

Cascaded multilevel inverter (CMI) topology is prevalent in many applications. However, the CMI requires many switches and isolated dc sources, which is the main drawback of this type of inverter. As a result, the volume, cost and complexity of the CMI topology are increased and the efficiency is deteriorated. This paper thus proposes a switched-capacitor-based multilevel inverter topology with half-bridge cells and only one dc source. Compared to the conventional CMI, the proposed inverter uses almost half the number of switches, while maintaining a boosting capability. Additionally, the main drawback of switched-capacitor multilevel inverters is the capacitor inrush current. This problem is also averted in the proposed topology by using a charging inductor or quasi-resonant capacitor charging with a front-end boost converter. Simulation results and lab-scale experimental verifications are provided to validate the feasibility and viability of the proposed inverter topology.