| At present, diode rectifiers are adopted by DC traction power supply system for urban mass transit. In this system, the power is transferred in one direction from AC side to DC side. The DC voltage would rise up due to the left electrical brake energy of metro vehicles. Resistance braking equipments can solve this problem, which would waste the energy and bring new problems like temperature rise. It is economic to make good use of the great electrical brake energy.In this dissertation, energy feedback traction power supply system is researched to solve the problems above. The novel system adopts three-phase voltage source PWM rectifier as converter unit, which can work in rectification or inversion according to energy flow ways. The left electrical brake energy will be feed to the AC network. In this dissertation, system structure and operational principle are introduced. AC side harmonic and DC side characteristic are analyzed specially. Firstly, harmonic analysis algorithm is discussed in details, which is proved by experimental result. Its calculation formulas are given and programmed. The reason for harmonic elimination by dual control method is also analyzed, which is proved by simulation. According to harmonic national standard, comparison with harmonic distribution of present power supply system is given. Secondly, the characteristics of system output, steady state operation and short circuit of DC side are simulated. Technical specifications of the system are given. Finally, main circuit hardware design and control system scheme are presented. The initial experimental results show the good performance of the system. It is proved that energy feedback traction power supply system is reasonable and feasible.
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