PUBLICATIONS

This paper proposes a fault-detection method for open-switch failures in hybrid active neutral-point-clamped (HANPC) rectifiers. The basic HANPC

topology comprises two SiC-based metal–oxide–semiconductor field-effect transistors (MOSFETs) and four Si insulated-gate bipolar transistors

(IGBTs). A three-phase rectifier system using the HANPC topology can produce higher efficiency and lower current harmonics. An open-switch fault

in a HANPC rectifier can be a MOSFET or IGBT fault. In this work, faulty cases of six different switches are analyzed based on the current distortion

in the stationary reference frame. Open faults in MOSFET switches cause immediate and remarkable current distortions, whereas, open faults in IGBT

switches are difficult to detect using conventional methods. To detect an IGBT fault, the proposed detection method utilizes some of the reactive

power in a certain period to make an important difference, using the direct-quadrant (dq)-axis current information derived from the three-phase

current. Thus, the proposed detection method is based on three-phase current measurements and does not use additional hardware. By analyzing

the individual characteristics of each switch failure, the failed switch can be located exactly. The effectiveness and feasibility of the proposed fault-

detection method are verified through PSIM simulations and experimental results.