Management and Utilization of Urban Rail Transit Regenerative Braking Energy Based on the Bypass DC Loop

Urban rail transit (URT) has become a major energy consumer in the city and increasing the utilization rate of trains' regenerative braking energy has become an important measure to reduce traction energy consumption. In view of the drawbacks of the traditional braking energy management and utilization mode, this article proposes a new method of URT regenerative braking energy management and utilization based on bypass dc loop (BDL). An analysis is made of its functional mode and working mechanism, and then a traction network BDL topology and its control strategy based on power electronic converter are proposed. The feasibility and effectiveness are verified by the scenario analysis method. The simulation results show that the BDL can effectively improve the utilization rate of regenerative braking energy and raise local traction network voltage by scheduling the braking energy of trains over a long distance. It serves the function of an “energy saver and voltage stabilizer.” When combined with the stationary energy storage system (ESS), it not only further improves the efficiency but also reduces the charging and discharging frequency and the depth of the ESS. As a result, the service life of the ESS is extended. The research findings can provide reference for the management and utilization of URT regenerative braking energy.