Design On Control System Of Low-speed Brushless DC Motor In Electric Vehicle

With the increasing depletion of global resources and continuous increase of theenvironmental pressures, the emergence of electric vehicle will become the maindevelopment direction of the automotive industry. Among the systems of electric vehicle,motor and control system of motor play integral role, whoser research and optimizationare also the focus of attention of car manufacturers in the world. This paper selectsbrushless DC motor (BLDCM), which has precise control, good heat dissipation as well asthe advantage of simple structure.It is an energy-efficient drive motor of electricvehicle,therefore, the paper presents a control system of permanent magnet brushless DCmotor based on the low-speed electric vehicles, the key introductions are as follows:1) The article discusses the current development of brushless DC motor and drivecontrol system,introduces its structures, analyzes its working principle and operatingcharacteristic,and makes simple explanation to the design of motor body;2) Several common control methods for brushless DC motor are compared. In orderto reduce torque ripple, direct torque control (DTC) method are highlighted. Based on theprinciple and mathematical equations of direct torque control of brushless DC motor,simulations are built in the working environment of Matlab/Simulink;3) In order to achieve stable operation of electric vehicle, the choice of controllercore chip for brushless DC motor is microcontroller STM32F051produced by ST, basedon which we build drive control system of brushless DC motor,and describe the main partof the hardware circuit of brushless DC motor controller;4) We build an experimental platform,conduct dynamometer tests to the prototypedeveloped jointly by research group, and compare the actual measured waveforms withthe previous simulation.The results show that the performance of direct torque controlmodel for brushless DC motor are in line with the actual use of the motor.