Research on the Regeneration Braking Energy Feedback System of Urban Rail Transit

Regenerative braking energy feedback system (RBEFS) can effectively feed the regenerative braking energy (RBE) of the trains back to the ac power grid. This improves the economy of the urban rail transit system greatly. The RBEFS that is utilized for both recycling the RBE and controlling the voltage of the traction network is proposed in this paper. First, the structure of the medium voltage RBEFS with the higher recovery efficiency is presented, and its parameters are designed in detail. Then, the double closed-loop control strategy of the RBEFS is studied, which not only achieves unit power factor feedback but also stabilizes the voltage of traction network effectively. Finally, simulation based on MATLAB/Simulink, laboratory experiments, and the field test are used to verify the performance of the presented RBEFS. The simulation and experiments results show that the RBEFS is able to feed RBE back into the ac grid effectively and the power quality of its output current satisfies the requirements of grid connection, as well as mitigate the voltage rise of the traction network under different startup threshold perfectly.