Fault-Tolerant Five-Level Switching-Cell Current Source Inverter

A topology with a reduced component count, referred to as the different multilevel current source inverter (DML-CSI), has been introduced in the literature. However, similar to other CSIs, DML-CSI also suffers from the issue of open-circuit faults (OCFs), which are reported to be the most common and destructive failures in industrial settings. In addressing this significant drawback, this article introduces a new configuration termed the fault-tolerant switching-cell CSI (FT-SC²SI), derived from the DML-CSI circuit. To enhance the proposed topology's resilience against severe OCF scenarios and avoid the need for an additional closed-loop controller, the phase-shifted pulsewidth modulation (PS-PWM) method is employed. Notably, the proposed solution is straightforward and does not necessitate any fault diagnosis or other complex controllers. Furthermore, the PS-PWM operation under faulty conditions does not require modification. Likewise, the quality of the waveforms is not compromised during the faulty operating conditions. Experimental results are provided to substantiate the findings.