PUBLICATIONS

This thesis proposes an open-switch fault detection and a fault-tolerance control method for three-level grid-connected hybrid active 

neutral-point-clamped (ANPC) inverters. A hybrid ANPC inverter is composed of six switch devices per a leg. Among six switch devices, two switch 

devices are silicon carbide (SiC) MOSFETs and four switch devices are silicon (Si) IGBTs. The performance and efficiency of hybrid ANPC inverter are 

improved by using SiC semiconductor devices. Open-switch faults cause the distortion of output phase current, deteriorated inverter performance, and decreased reliability. The fault detection and  tolerance control are required essentially for improving reliability of the inverter system because lots of 

switch devices are used for the ANPC inverter. The proposed fault-tolerance method can be implemented simply through a change of the reference 

waveform for voltage modulation. The proposed methods can be applied without additional sensors or passive elements such as resistor, inductor, or 

capacitor, thus the additional cost is not required for applying the proposed method. The effectiveness of the proposed fault detection and 

fault-tolerance control method was validated by the simulation and experimental results.