Design and analysis of emergency self-traction system for urban rail transit vehicles

This paper firstly proposes a concept of emergency self-traction system (ESTS) for the urban rail transit vehicles with an onboard hybrid energy storage system (ESS). The onboard ESS consists of the high-energy-density batteries and the high-power-density supercapacitors. The topology of the ESTS is elaborated in the second part. The DC/DC power converter for hybrid ESS is dedicatedly designed to take full advantage of different energy storage devices, and also suitable for the existing vehicle electric system. Then, the flowchart of the ESTS control system is presented to illustrate the ESTS operation in emergency self-traction mode. Finally, the simulation results from MATLAB are shown to demonstrate the validity of the architecture and the control strategy of ESTS.