YoungJong Ko, Ju-Yeon Baek, Eun-Kyeol Shin, and Kyo-Beum Lee, "DC-Link Capacitor RMS Current of CHB Inverter under Open-Switch Failures," Journal of Electrical Engineering & Technology, in press. -SCIE > Paper

Cascaded H-Bridge (CHB) inverters have been attracted in high power application fields due to flexible power scalability with low voltage rating power semiconductor devices, whereas the increased number of the power semiconductor devices which are prone to failure has incurred the reliability issue. The present studies to improve the reliability have been focusing on fault detection, localization, and tolerant method of the switching device failure. 

Namely, it is missing to consider influence of the failure on DC-link capacitors, even though the capacitors are another major failure causes. In this

work, the influence of the open-switch failure on the DC-link capacitor current is analyzed, considering a 7-level CHB inverter modulated by either the phase-shifted carriers or the level-shifted carriers. The capacitor current in rms is mathematically derived when the CHB inverter is under the open

-switch failure and finally, the theoretical outcome is experimentally confirmed.