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IGBT开关单元面临的损耗与可靠性挑战,本文在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。因此本文在分析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本文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 in urban rail transit. As one of key devices, switch unit (SU) transfers thousands of amps traction current from the running rails to return cable. In view of the challenges of loss and reliability for the IGBT-based SU, this paper employs silicon controlled rectifier switch unit (SCR-SU) in ZRCS. However, SCR-SU faces the turning off problem. Based on analysis of SCR-SU turn-off mechanism, a SCR-SU turn-off strategy with negative resistance converter from system aspect is proposed. Simulation and experimental results indicate that the ZRCS with SCR-SU can realize SCR-SU’s turning off by adopting the proposed SCR-SU turn-off strategy. With its normal operation, ZRCS with SCR-SU can effectively reduce the stray current in urban rail transit system, and has a good application prospect.

TM 922； TM 46