Design And Research Of BLDC Fuzzy Controller Based On FPGA

Brushless dc motors with advantages of simple structure,good mechanical properties,good speed regulation performance are widely used in electric vehicles,aerospace and other fields.At the same time,BLDC and its control technology are faced with difficulties and challenges in the process of development.At present,most of motor controllers use DSP or MCU as its main control chip.However,this kind of software controller perform certain problems.In applications of BLDC,there are often many spike pulses,when they input to the controller,they will interfere with CPU of the controller,cause the damage of program and system instability.Aiming at this problem,this thesis presents a hardware BLDC controller based on FPGA,it will take full advantages of the hardware characteristic of FPGA,improve the anti-interference ability,execution speed and control precision of the controller.This thesis starts working from the structure of BLDC,aiming at problems of the traditional PI control algorithm in response performance and control effects,combined with the fuzzy control theory from the intelligent control,then proposes the fuzzy adaptive PI control algorithm.At the same time,this thesis analysis the reason of torque ripple of BLDC,propose torque ripple restrain method of PWM_ON_PWM control,which is different from common PWM control modes in view of non-conduction phase diode freewheeling in the process of motor running.This thesis designs the fuzzy PI controllerby using the MATLAB fuzzy toolbox,and constructs the BLDC control system model using SIMULINK.This thesis carries out simulation analysis on the control system,compares control performance of the fuzzy PI with of traditional PI control,and torque ripple restrain effect of PWM_ON_PWM with of H_PWM-L_ON control mode.In FPGA controller designing,this thesis uses the top-down and the modular design concept to construct digital function modules,maximizes advantages of FPGA.This thesis designs hardware circuits and builds experimental platform of BLDC control system based on FPGA.Finally,this thesis verifies experiment and get the final conclusion.BLDC controller based on FPGA has high implementation speed,high control precision,strong anti-interfere capability.Fuzzy PI has a better performance than traditional PI control.PWM_ON_PWM has a better restrain effect than H_PWM-L_ON control mode.