Modulation for Extended Fault-Tolerant Operation in Cascaded H-Bridge Inverters

Cascaded H-bridge (CHB) multilevel inverters are constructed with multiple single-phase H-bridge cells connected in series, yielding a multilevel output voltage. Consequently, their primary benefit lies in achieving higher power quality with reduced filter inductance. Additionally, the modular structure allows for flexible design of rated voltage and power. However, CHB inverters utilize a high number of power semiconductor devices, making them susceptible to increased failure probability and thereby diminishing the system’s reliability. This paper proposes a novel fault-tolerant strategy designed to further enhance the reliability by reducing power losses in power semiconductors. The effectiveness of the proposed method is verified through simulation and experimental results, comparing its performance with that of the conventional method.