Research on Optimal Power Flow Control Strategy for Urban Rail Flexible Traction Power Supply System

In order to solve the problems of uncontrollable DC voltage and low utilization of regenerative braking energy in traditional traction power supply system, a bi-directional converter is used instead of diode rectifier to form a flexible traction power supply system. Firstly, the AC network and DC network of the system, as well as the working mode are introduced. Then a system hierarchical control strategy is proposed to study the modeling, dual closed-loop control of the bidirectional converter, and the optimization objectives, variables, and Gray Wolf optimization algorithm are introduced to achieve flexible control of the system. Finally, a simulation example is given to verify the proposed control strategy. The results show that the control strategy can better improve the regenerative braking energy distribution of the train and realize the energy-saving optimization of the system.