Research On The Control System Of Brushless DC Motor For Pure Electric Vehicles

With the global energy crisis and environmental pollution problems worsening,more and more traditional internal combustion engine vehicles have been criticized.Traditional internal combustion engine cars can not satisfy people's demands due to their dependence on fossil fuels and the emission of their own harmful exhaust gases.New energy vehicles has become a major measure to solve the problem,all countries attach importance to the new energy vehicles are also increasingly apparent.Many developed countries in Europe and the United States have promulgated the final ban on the sale of fuel vehicles.At present,China has also proposed a large number of concessions and subsidies to promote the development of the new energy automobile industry.It not only solves the environmental and energy problems,but also realizes China's automobile industry Rise,to break the dependence on traditional automobile technology in Europe and the United States.By reading a lot of literature,this dissertation analyzes and summarizes the current development trend of new energy vehicles in the world,makes a comparative analysis of the domestic and foreign research status on electric vehicle motor control unit.Summarizes the current several new energy vehicles commonly used motor and its characteristics,comparative analysis of the merits of the motor.In this dissertation,the brushless DC motor is chosen as the power source,the controller of brushless DC motor is designed,and the corresponding control strategy is worked out.First of all,the mathematical model of brushless DC motor is established,and Simulink simulation test platform of brushless DC motor controller is constructed at the same time.In this dissertation,the torque ripple problem of brushless DC motor and the motor double closed-loop speed control system problem are studied ?simulated and analyzed deeply by mathematical model and simulation test platform.The commutation torque ripple rejection strategy is analyzed and developed in two-phase stationary coordinate system and at the same time fuzzy PI closed-loop speed control system control strategy based on the fuzzy control theory is developed.According to the functional requirements of brushless DC motor control system,this dissertation completes the hardware and software design and chooses the TI's TMS320F2812 as the master chip.Hardware part includes power circuit,power inverter circuit,current sampling circuit,position detection circuit,communication circuit,drive circuit and several other modules.The software part of the control system mainly includes the system initialization main program,current sampling interrupt subroutine,the communication interrupt subroutine,commutation interrupt subroutine.The reliability and rightness of the hardware control circuit and the effectiveness of the control strategy are verified through the experimental platform.In addition,this dissertation also uses Labview software to establish the host computer monitoring software,to give command to the motor and monitor state parameters of the motor.Experiments show that the motor controller is reliable and the commutation torque ripple suppression strategy and fuzzy PI double closed loop speed control system strategy are effective.