| Small electric vehicles represented by electric bicycles and electric motorcycles have the advantages of energy conservation,environmental protection,moderate price,portability and flexibility,and they are commonly used as a means of transportation.The motor driving system,which is the core part of electric vehicles,affects the speed regulation performance and torque control performance of electric vehicles.It is of great significance to develop high-performance motor driving system to improve the overall performance of electric vehicles and promote the promotion of electric vehicles.In this paper,the vector control driving method was used to develop the brushless DC motor driving system for small electric vehicles from the aspects of scheme design,software and hardware design and experimental analysis.Firstly,the mathematical model of the brushless DC motor in different coordinate system was established.The components of the driving system were analyzed according to the principle of vector control method,and the scheme of the driving system was designed.According to the engineering design method,the mathematical model of the double closed-loop control of the speed loop current loop was established,and the parameters of the double closed-loop controller were theoretically calculated.The simulation model of the driving system was established in Simulink.The simulation was carried out under different working conditions to analyze the changes of motor speed,torque and phase current,and the feasibility of the design was verified.Secondly,the functional requirements of the brushless DC motor driving system were analyzed,and the hardware structure of the driving system was determined.The hardware circuit of the motor driving system for electric bicycles and electric motorcycles were designed according to the motor parameters,including power module,inverter module,signal detection module and protection circuit module.Based on the hardware circuit,the software structure of the driving system is determined according to the driving system scheme and functional requirements.The main program and various interrupt programs were designed to realize current sampling,rotor position and speed detection,double closed-loop control,space vector pulse width modulation and other parts.Finally,the experimental platform of the motor drag dynamometer system was built.The dynamometer system was used to apply the adjustable load torque to the motor.The speed response performance and torque stability performance of the motor were tested and analyzed.The changes of the motor speed,torque,and phase current under different target speed and load torque were analyzed.The experimental results showed that the motor driving system designed by the subject met the corresponding design indicators. |
