零阻变换器系统中晶闸管开关单元的关断策略

零阻变换器系统(zero-resistance converter system,ZRCS)是一种治理城市轨道交通杂散电流的电力电子方案,开关单元作为其关键部件之一,用于将高达数千安的牵引电流由走行轨转移至回流线缆.鉴于绝缘栅双极型晶体管IGBT开关单元面临的损耗与可靠性挑战,在ZRCS中采用了晶闸管开关单元(sili...

Turn-off Strategy of SCR Based Switch Unit in Zero-Resistance Converter System

Zero-resistance converter system (ZRCS) is a power-electronic-based stray current mitigation measure for urban rail transit. Switch unit (SU), as one of the key devices, transfers thousands of amperes of traction current from the running rails to the return cable. To address the challenges of loss and reliability for the insulated gate bipolar transistor (IGBT)-based SU, this study employs a silicon-controlled rectifier switch unit (SCR-SU) in the ZRCS. However, an SCR-SU faces a turn-off problem. Based on the analysis of the SCR-SU turn-off mechanism, an SCR-SU turn-off strategy with a negative resistance converter from the system aspect is proposed. Simulation and experimental results indicate that the SCR-SU in ZRCS can be turned off by adopting the proposed SCR-SU turn-off strategy. With its normal operation, the ZRCS with SCR-SU can effectively reduce the stray current in urban rail transit systems and has good application prospects.