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Urban rail transit DC traction power supply system uses a diode rectifier , power net unidirectional flow only from the AC mains to DC traction . When the braking of the vehicle , the excess regenerative braking energy to the DC power grid voltage increases . The traditional solution is the the setting resistor braking device , but this will cause a great waste of energy and bring the temperature rise and other problems . Due to the frequent rail vehicle braking , the the considerable braking energy , if reasonably use will be able to produce good economic results . In view of the above situation , this paper, a new power supply system - feed-forward traction power supply system . The system uses a three-phase voltage -type PWM rectifier converter unit , the energy flow in the switch between the rectifier , inverter conditions , can be the excess regenerative braking energy back to the AC grid . This paper introduces the structure and working principle of the system , to expand the application of research focuses on the system from the AC side harmonics and DC side features two . First , a detailed discussion of the harmonic analysis algorithm , the calculation formulas and programming , test results prove the accuracy of the algorithm . Simultaneous analysis of the mechanism of the duplicated control of harmonic elimination , given simulation . Harmonic national standards , compared to the existing power system harmonic distribution . Secondly , this paper simulation study three aspects of the system output characteristics , characteristics of the steady-state operation , the DC side short circuit characteristics , system performance . Finally, the main circuit of the system hardware design, control system design . The preliminary test results show that good system performance . This paper studies prove Traction Power Supply System - fed reasonable and feasible , with the application of value .
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