可控电流源型换流器 IGCT 串联均压技术

The control of voltage sharing is one of the core technologies of the current source converter based on series connected integrated gate commutation thyristor (IGCT). At present, there is a lack of research and testing on series-connected IGCTs, specifically addressing the inconsistencies in turn-on and turn-off characteristics caused by variations in IGCTs, trigger delay and snubber parameters. First of all, the mechanism caused voltage unbalance is carried out and a sub-module circuit for voltage sharing is proposed in this paper. Then, the inconsistency factors leading to IGCTs’ turn-on inconsistency is analyzed, and the coordination between the IGCT utilization and protection voltage ratio is suggested. After that, this paper analyzes the natural and active turn-off characteristics and recommends snubber parameters. Finally, a test platform and an 8-level series IGCT module prototype are developed to verify the performance. Significantly, the test results indicate that the inconsistency of the voltage among IGCTs is controlled within 8%.