Control Strategies for Improving Energy Efficiency of Train Operation and Reducing DC Traction Peak Power in Mass Rapid Transit System

This paper presents two strategies to improve energy efficient operation in a mass rapid transit (MRT) system. First, a controller based on fuzzy logic control is developed to provide speed reference needed by the trains. The controller model is developed by considering 2 inputs: third rail voltage condition and deviation between scheduled time and actual operation time. The aim of the controller in this research is to reduce energy consumption and maintain inter-station running time of the train. Second, an on-board energy storage system (ESS) which uses a supercapacitor in order to store energy is modeled. A half-bridge bidirectional converter is used to determine the charging or discharging modes of the supercapacitor. The charging and discharging currents are controlled by a simple PI controller. Four case studies are investigated to show the effects of the speed controller and the supercapacitor. The simulation results indicate that if booth speed controller and ESS are used in a MRT, the fluctuation of third rail voltage will be kept small and the energy required from TSS is also reduced.