Development And Application Of Brushless DC Motor Control System Based On Model Design

In modern society,electricity is the most used and most common secondary energy source.As an electromechanical energy conversion device,the motor has been applied in all aspects of modern society and national economy.Brushless DC motor(BLDCM)has gradually become the first choice for drive motors because of its large starting torque,strong overload capability and high efficiency.It has broad prospects.In this paper,the BLDCM is taken as the research object,and the motor control system is developed based on the advantage of the model design method,which can greatly shorten the development cycle and improve the development efficiency.The main research contents of this thesis are as follows:Firstly,this paper has a study of model-based design method.The design flow and advantages of the model are given.At the same time,the process of automatic code generation and the detailed process of automatic code generation are analyzed in detail,providing a theoretical basis for automatic code generation of the motor control system.Secondly,this paper has introduced the basic structure of BLDCM and established the mathematical model of the motor.Taking the three-phase full-bridge drive circuit as an example,the working principle of the BLDCM is analyzed in detail.The process of motor commutation is illustrated by the given power tube conduction judgment table.Giving three kinds of BLDCM speed control methods,besides,this paper emphasizes the PWM speed regulation mode in voltage regulation and analyzes how to realize PWM speed regulation by changing the duty ratio.It proposes a fuzzy PID control scheme for BLDCM speed control system,realizing the PID parameter tuning by establishing fuzzy control rule table.The fuzzy controller query table,which is obtained by defuzzification,can realize real-time control and improve the response speed and control precision of the speed control system.Then,this paper has designed BLDCM control system which is based on Freescale MC9S12XEP100 microcontroller,at the same time,the hardware and software parts of the motor system are designed.The hardware part mainly includes several importantcircuits such as power supply circuit,power drive circuit,rotor position signal detection circuit and speed input circuit.However,the software part is designed in combination with the hardware part.According to the needs of the control system,it gives the program flow chart of the main modules such as the main program and the interrupt service program.Finally,this paper has configured MC9S12XEP100 microcontroller underlying driver module library and analyzed how to underly these modules in detail.Using the stateflow in Simulink to build a BLDCM control model for algorithm verification of the model,this paper is aimed to achieve the BLDCM automatic code generation,and the generated embedded C code,which is automatically generated,is downloaded through the emulator to the MC9S12XEP100 microcontroller.The experimental research is carried out after building the experimental platform of the BLDCM control system.The results show that the BLDCM control system is reasonable,reliable and stable.