Design Of BLDC Motor Speed Control System Based On FPGA

In recent years,the control and application of motor have pervaded throughout every field and link of national economy.Adopting electronic commutation to replace the mechanical commutation,the brushless DC motor has simple structure,convenient maintenance,reliable operation,and wide range of speed,which make it become a hot spot of research in the field of high precision controls.The presented topic takes the permanent magnet brushless DC motor(BLDCM)as the control object,using FPGA as control core,to design the speed control system.Firstly,by deeply analyzing the basic structure,working principle and mathematical model of brushless DC motor,this paper establishes the scheme of double closed-loop brushless DC motor control,and with the aid of MATLAB/Simulink simulation platform,the whole simulation model of Brush-less Direct Current Motor has been built.The traditional PI control has been implemented in the inner current loop?With respect to the outer speed loop which has a decisive influence on the control of the motor,this paper implements the following three control algorithms:the traditional PI control,fuzzy PI control and variable universe fuzzy PI control.Comparison tests have been carried on the simulation model.The simulation results show that under variable universe fuzzy PI control strategy,the system has better dynamic and static performance.Secondly,on the basis of the theoretical simulation,the FPGA chip EP2C70F896C6 of ALTERA company is selected as the core of the controller,and the software and hardware design of Brushless DC motor speed control system is carried out.In FPGA hardware design,the main control circuit with FPGA as the core,drive circuit,current sampling circuit,Hall signal detection circuit,A/D conversion circuit and other peripheral circuit design of Brushless DC motor have been implemented according to the system requirements.In software design,fuzzy PI control module in variable universe?PWM module?Hall speed detection and commutation module?serial communication module?A/D conversion module and other specific methods have been implemented by Hardware Description Language and EDA modular design.Finally,the function of each module of the system is simulated in Modelsim software to verify the correctness of the program.Furthermore,the hardware is implemented and verified on the hardware platform.At the same time,in order to facilitate the debugging and analysis of the motor performance,this paper also uses VC++ to develop the host computer monitoring interface,which can monitor the operation of the motor in real time.Through the comparison and analysis of the experimental results,it is proved that the brushless DC motor speed control system designed in this paper has good control performance.