Research On High-voltage DC Chopper For Locomotive Traction

As a DC-DC converter that converts DC power into another fixed or adjustable voltage,DC chopper is widely used in DC drive systems,charging and storage circuits,switching power supplies,and various electrical equipment.A variety of conversion circuits such as buck chopper circuit,boost chopper circuit,buck-boost chopper circuit,and composite chopper circuit have appeared.The application of DC chopping technology in the switching power supply and DC motor drive makes its control obtain the effects of accelerating smooth,fast response and saving electric energy.This paper aims at the problems of poor voltage stabilization effect,slow voltage response speed and large line voltage drop of traditional locomotive DC traction power supply,combining DC/DC conversion technology with digital control technology to study the basic problems of 1080kW DC chopping power supply.The thesis first introduces the development status and trend of DC chopper.On this basis,the power supply system is designed in combination with performance indicators.The system is divided into a power main circuit and a control circuit.Among them,the power main circuit adopts the buck chopper topology,and uses IGBT as the core device of power conversion to develop the design of the power main circuit.The control circuit takes TMS320F2812 as the core of the system control,and performs PWM control on the step-down chopper circuit to realize wide-range adjustment and closed-loop control of the output voltage.In addition,the corresponding signal sampling circuit,fault protection circuit and software program design are designed around the chip to ensure the safe and reliable operation of the system.Finally,the system simulation experiment circuit was built with the help of Matlab and Pspice simulation software.The experimental results show that the power supply system works normally and the performance is good.