Comprehensive Analysis and Experiments of RB-IGCT, IGCT With Fast Recovery Diode and Standard Recovery Diode in Hybrid Line-Commutated Converter for Commutation Failure Mitigation

Commutation failure is one of the most important factors threatening the safety of multi-infeed high voltage direct current systems. To mitigate commutation failure, we have proposed a novel hybrid line-commutated converter by adding fully controlled devices to the conventional line-commutated converter. It aims to achieve auxiliary commutation and forced commutation with the help of fully controlled devices. Based on the novel hybrid line-commutated converter topology, the study investigates how to select suitable fully controlled devices and how to design the appropriate parameters of the devices. First, this article studied the general characteristics of reverse-blocking devices, including reverse-blocking integrated gate-commutated thyristor (RB-IGCT) and asymmetrical IGCT with diode (including fast recovery diode and standard recovery diode). Then, the novel commutation principle is carefully proposed and analyzed. The comprehensive simulation results and comparison study of the novel commutation principle are conducted. Then, according to the proposed commutation principle, the voltage and current working stress of devices are illustrated. According to these, vital features of devices, including recovery speed, on -state voltage, current conduction ability, surge current, maximum turn- off current, robustness, and volume of devices, are carefully analyzed and compared. Related experiments are conducted to present the vital characteristics of devices in the equivalent operating conditions in converters. Finally, the advantages and disadvantages of RB-IGCT and IGCT with fast recovery diode and standard recovery diode are comprehensively presented, which offers valuable reference considered in engineering applications.