Fault-Tolerant Switching-Cell Flying Capacitor Clamped Current Source Inverter

A topology with modularity and scalability features, referred to as the flying capacitor clamped current source inverter (FC³SI), has recently been introduced in the literature. However, it is prone to open-circuit faults (OCFs), which significantly endanger system reliability. To address this major limitation, a modified topology called the fault-tolerant switching-cell FC³SI (FT-SCFC³SI) is introduced in this article. The proposed topology utilizes phase-shifted pulse-width modulation (PS-PWM) method to tolerate simultaneous and frequent OCFs across all power devices, while still preserving the natural voltage balance of the flying capacitors. Unlike several existing CSCs, the suggested inverter eliminates the need for multiple dc sources and/or inductors. A fault-tolerant analysis is carried out and substantiated by experimental results from laboratory tests.