AC-DC Multi-port Traction Power Supply System with Power Electronic Transformer

In this paper, an AC-DC multi-port traction power supply system with power electronic transformer is put forward. Based on this structure, the system control method is proposed to realize energy optimization and system stabilization. The system control method is proposed to divide the system state and utilize DC bus voltage information, aiming at achieving optimal energy utilization and system stability. The system consists of PV (photovoltaic) source DC system, wind energy communication system, energy storage module, regenerative braking module, DC micro-grid power supply module and local load, which can run in grid or island mode. The system is divided into five working modes, which are the main control DC bus voltage of PV source DC system under balanced state, the main control of island operation energy storage module, the main control of regenerative braking module, and the main control and communication of regenerative braking module in grid mode. The control methods of the PV interface converter, the grid side interface converter and the energy storage interface converter are respectively given. The simulation and the test results proof the usefulness of the proposed method.