Research On Automatic Speed Control System Of Controlled Retarder Applied To Railway Marshalling Station

In order to supervise and control the train speed in railway marshalling station, an automatic speed control system of controlled retarder based on a distributed control system is designed.Aiming at problems in present automatic speed control system, present control system is improved and an automatic speed control system of controlled retarder based on a distributed control system is designed in this thesis. The main task of this thesis is to design a new fashioned intelligent power module of controlled retarders. The system is a DCS made up of one master and forty-eight slaves. The master is an industrial control computer with a real-time supervision software and every slave is an intelligent power module supplying to many retarders in one control site, whose core is MSP430 MCU. Data are transmitted according to user-defined communication protocols between master and slaves on RS-485 bus. The master calculates the number of retarders, which react on each reference point by reading parameters, such as speed, weight of trains, rub coefficient and the position of parking. Then the value of output current is transmitted to each intelligent power module. After receiving these data, each slave outputs corresponding current and feeds back the operating state of control site, such as short circuit, open circuit, normal state etc., to master. So the commands send to the next control point can be adjusted correspondingly.The key part of this thesis is the software and hardware design of the driving power module of the retarder control system. The hardware design of power module includes main loop and MCU control circuit. The main loop consists rectification circuit of SCR, trigger control circuit, sampling and detecting circuit. The MCU control circuit includes the PWM output circuit, reset circuit and clock circuit. The schematic diagrams of main circuit, MCU control circuit and other parts are provided. Software of the intelligent power module driving retarders is programmed in assembly language, including main program, PID adjusting subroutine, PWM pulse generation subroutine, scale transform subroutine receiving and transmitting interrupt subroutine.