Research And Design Of Control System Of Wheel Motor Running In Test Bench

With the advantages of environmental protection,energy conservation,large carrying capacity,safety and reliability,Rail Transport occupies a very important position in the field of public transport in China.In recent years,with the development of high-speed EMUs,Rail transit is a major artery of transportation in my country,which has the characteristics of faster and more convenient,comfortable and on time.Wheel set motor assembly is the most important part of the locomotive running gear,and wheel-motor is the most important part,which determines whether the locomotive can run normally.Therefore,the wheel--motor grinding test must be carried out before the motor is loaded.According to the requirements of wheel-motor grinding test,a grinding test-bed control system is designed in this project for the traction motor of CRH2 high-speed EMU.The thesis has three parts: the main circuit of the system,the hardware of the control system and the software of the system.The electric traction drive system is briefly introduced,and the technical route from the power supply to the input of the traction motor is cleared out,which provides a reference for this thesis.The structure and parameters of traction motor of CRH2 high-speed EMU are analyzed,combined with test method for Three-phase Asynchronous Motor and CRH2 EMU level 4 maintenance specification,it is concluded that the requirements of running test are to adjust the voltage observation current and the forward and reverse speed control when the frequency is constant.Then,through the research on speed control method of traction motor,the scheme of SPWM frequency conversion speed control is proposed.Based on this,the main circuit design scheme of low voltage frequency converter & boost transformer is adopted,and the control strategy of the combination of bipolar SPWM control and PID control is determined to match it.The low voltage frequency converter is composed of three-phase uncontrollable rectifier circuit and three-phase fully controlled voltage DC-AC circuit.The control system needs to collect signals such as voltage,current,velocity,temperature of the traction motor and sends them to the upper computer for processing.The minimal system circuit,including power circuit,clock and reset circuit and configuration circuit,is designed in this project,which uses a programmable logic device(PLD)as control chip.Besides,designing 8-channel A/D conversion circuit,designing USB communication circuit communicating with upper computer,designing IGBT drive circuit and overvoltage protection & overcurrent protection circuit are all done.The software design is divided into the digital programming of the FPGA and the human-computer interaction program of the upper computer.The digital programming of the FPGA is to verify the structure of the digital circuit and the logic of the timing sequence.This thesis chooses to use Verilog language to program on Quartus Prime platform,where the timing logic of modules is the focus of the FPGA.The system includes clock module,A/D sampling module,FIFO cache module,USB communication module and its firmware program,PI algorithm module,PWM waveform generation module.The upper computer program,which is the interface of human-computer interaction,is written in the Visual Studio development environment with C# language.It can complete the functions of display,storage,deletion,saving data to U disk after collection,and control the motor forward and reverse,voltage regulation,speed control.