Research On Control System Of Salient-pole Rotor Brushless Electrical Excitation Motor Applied In Electric Vehicle

With the serious situation of energy shortage and environmental pollution,the new energy vehicle has become the trend of the society development,therefore the electric vehicle using the developed motor as the power source is drawing more and more attention.The electric vehicle with the form of four-wheel drive has its unique advantages and technical characteristics in dynamic energy transfer,chassis structure,control strategies and so on,however it needs higher requirements on the motor performance.This thesis adopts Salient-pole Rotor Brushless Electrical Excitation Motor(SRBLEEM)which is a new type motor,as the traction motor of the four-wheel drive electric vehicle.It has not only the characteristics of simple structure,high reliability and quality of torque ratio which are the feature of the traditional brushless dc motor,but also the advantages of low rotary inertia,short starting time,high starting torque and expanding speed.At the same time it avoids the disadvantages that the flux of traditional permanent magnet brushless DC motor can not be adjusted,demagnetization risk,and high speed performance is restricted by mechanical strength.Firstly,the thesis introduces the basic structure and working principles of SRBLEEM,and builds the 3D model in the software of ANSYS Maxwell according to the basic parameters of the motor,then uses three dimensional finite element method to analyze the mechanical characteristics and the transient electromagnetic characteristics of SRBLEEM,and verifies that SRBLEEM can meet its performance requirements as the traction motor of electric vehicle.Secondly,according to characteristics of the SRBLEEM,the chopper voltage control method has been chosen,and the speed and current double closed loop PI control strategy has been designed.Furthermore the thesis sets up a control system based on Digital Signal Processor 28335 including hardware circuit and software program,and verifies the motor's performance and the control method's feasibility through the experimental platform of the SRBLEEM control system.Finally,to verify the traction performance of the SRBLEEM as the drive motor of four-wheel electric vehicle,the simulation model has been set up in MATLAB/Simulink.Based on the experimental data of the motor with setting of second-order inertial link,the SRBLEEM simulation model is established,which uses the recursive least squares to identify the model parameters with the experimental data as the input and output.At last,putting the motor model into the vehicle model,the simulation results can verify the motor traction characteristics,and it provides a theoretical basis for applying the SRBLEEM into the four-wheel drive electric vehicle.