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(silicon controlled rectifier switch unit，SCR-SU)，但面临着晶闸管无法自关断的问题。因此在分析 SCR-SU 关断机理的基础上，从 ZRCS 系 统角度提出了利用负阻变换器实现强制换流的 SCR-SU 关断策略。仿真和实验结果表明，采用 SCR-SU 的零阻变换 器系统能够在关断策略下实现晶闸管的关断，并能有效降低城市轨道交通系统的杂散电流，具有良好的应用前景。

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.

TM 922；TM 46

国家自然科学基金重点项目(51737001)；北京市自然科学基金(3222054)