A Novel Ultra-Fast Turn-Off Failure Detection Method of Integrated Gate Commutated Thyristor for VSC Application

• Published in: IEEE transactions on power electronics 2022, p.1-5
• Main Authors: Bai, Ruihang, Zhao, Biao, Yang, Chen, Chen, Zhengyu, Liu, Jiapeng, Zhang, Liang, Wu, Jinpeng, Yu, Zhanqing, Zeng, Rong
• Format: Article
• Language: English
• Subjects: Anodes; Capacitors; Cathodes; failure detection; Insulated gate bipolar transistors; integrated gate commutated thyristor; Logic gates; MOSFET; power electronic devices; Thyristors; voltage source converter
• ISSN: 0885-8993
• DOI: 10.1109/TPEL.2022.3222017

Integrated gate commutated thyristor (IGCT) has prospects in voltage source converter application. However, it has no desaturation characteristic in conducting state like IGBT, for which fast turn-off failure detection for blocking converter in deadtime is of great significance. In this letter, an ultra-fast IGCT turn-off failure detection method is proposed. Firstly, turn-off process and failure mechanism of IGCT is analyzed. It is clarified that turn-off capacitors of gate-driver will continue to discharge in turn-off failure, thus generating a voltage drop on turn-off MOSFET, which can be the criterion of failure. Then prototype, threshold and timing sequence are designed. Analog circuit including amplifier, hysteretic comparator and reference circuit is used for fast and accurate measurement of voltage on MOSFET. The failure gate current and fall time of turn-off trail current is measured in pulse test. Finally, experiments are carried out to verify the feasibility of the proposed scheme. The results show that the proposed scheme can achieve reliable turn-off failure detection within 19 microseconds. Neither false detection nor missed detection occurred. Proposed method has great accuracy and rapidity, and is convenient in implementation. It will greatly decrease the extreme failure rate of IGCT-based converters.