Research On Noninductive Control System Of Brushless Dc Motor Based On Fuzzy CMAC

Brushless DC Motor(BLDCM)is based on electronic commutation to replace the mechanical commutation of DC Motor,it has a wide speed range and high efficiency.These excellent features make the brushless dc motor more and more widely used,but with the increase of the application range,it is necessary to overcome the problems caused by special conditions such as high speed and low temperature.Under these circumstances,the position sensor cannot work normally,which will make it difficult to detect the rotation speed.In addition,the torque ripple exists,and the accuracy of the position and speed control will be greatly affected.Therefore,this paper mainly discusses the closed-loop drive of brushless dc motor without position and the method to restrain torque ripple.Firstly,the research status of sensorless drive and torque ripple suppression for brushless DC motor is analyzed.Based on the structure and working principle of the motor,the relevant mathematical model is established,and Pulse Width Modulation(PWM)is used to analyze the speed Modulation principle of the motor.This paper improves the starting acceleration method without position sensor,replaces the traditional V/F boost acceleration with the Constant current frequency boost acceleration,makes phase compensation for the terminal voltage detection signal on the basis of ensuring the low speed start performance,improves the accuracy of commutation,and reduces the torque ripple caused by commutation error.Then,the paper focuses on the analysis of the torque ripple suppression strategy.After comparing and calculating the commutation torque ripple of each PWM modulation mode in detail,the pwm-on mode with the minimum ripple is selected for further optimization.According to the strategy of torque ripple suppression based on phase current rate of change,the duty cycle of open phase and closed phase is adjusted in high and low speed range,so that the torque ripple can be suppressed in the whole speed range,and the feasibility is verified by the simulation experiment results.Next,this paper focuses on the closed-loop operation method,proposes a self-adaptive speed regulation method based on the cerebellar model articulation controller(CMAC),introduces its structure and design method,and compares the dynamic performance of traditional PID,fuzzy control and fuzzy CMAC based on the motor transfer function.And use MATLAB/Simulink software to build the modules of BLDCM,complete the simulation of the control system,and verify the advantages of fuzzy CMAC in BLDCM drive closed-loop control.Finally,the hardware control circuit of the brushless dc motor drive system was designed with TMS320F28335 as the main control chip,and the overall experimental platform was built.According to the overall block diagram of the system,the circuit schematic diagram of each part and the software program flow chart are designed,and the driving control scheme of brushless dc motor without position sensor is completed.