Research On Regenerating Energy Utilization System In Urban Rail Based On Supercapacitor

In urban rail transit, when train is in regenerative braking condition, the regenerative energy feedback to DC power supply network from the train, which will cause the supply network voltage rise, endangering the safety of the electrical equipment on the power network. To avoid this phenomenon, the current way is to consume the braking energy in the form of heat by absorption resistance; this caused tunnels temperature rise and energy waste. How to use regenerative braking energy circularly will be the focus.In this paper, the supercapacitor energy storage was used to design the energy recovery system. First, calculation the regenerative braking energy of urban rail transit vehicle. And, accordingly, calculation regenerative braking energy of multi-vehicle, baste on measured data of current and distance, build brake simulation of more cars subway train running, and to study the braking a vehicle under the influence of different grid spacing on the power supply bus voltage fluctuations, to determine the choice of the energy storage capacity of the multi-vehicle run-time.Secondly, introduce the working principle and the. advantages and disadvantages of the supercapacitor, according to the regenerative braking energy and power of the Trains, to select the supercapacitor. Determine the series and parallel combination program of the super capacitorAgain, in order to achieve the two-way flow of regenerative braking energy between urban rail trains and supercapacitor, introduced a half-bridge type of the Buck/Boost Bi-directional DC/DC converter, and establishment the unified mathematical model of the bi-directional DC/DC converter, and its control strategy; layered fit capacitor voltage balance control strategies in energy storage module, And bias current balance control strategy between energy storage modules.Finally, the article builds a200W energy storage module prototype, and verified the feasibility by experiment of the strategy of balance control in the energy storage module, and the main circuit control strategy. The storage system uses a modular design can adapt to different voltage levels of urban rail transit power supply system by changing the number of storage modules.