Brushless Dc Motor Control System Base On The Pic18f2431 Microcontroller

Not only brushless DC(BLDCM) motor has the advantages of the traditional DC motor such as the good regulation characteristics and large locked-rotor torque, but also it overcomes a range of issues which are brought about by the mechanical commutation by using of electronic commutator. All above make the brushless DC motor becomes one of current topics in the motor control areas.This paper introduces the hardware design and software design of brushless DC motor drive control system with the position sensor which is based on the PIC18F2431 MCU. The system uses MCU PIC18F2431 as the control chip. In the system hardware design, designs the external circuit of MCU, the hardware circuit of control part and the hardware circuit of drive part.The hardware circuit of control part including the rotor position feedback circuit, the speed of a given circuit, speed detection link and current detection circuit, the hardware circuit of drive part including power transistor drive circuit, three-phase bridge inverter circuit and isolation optocoupler circuit. Hall sensor used as a brushless DC motor position sensor, MCU according to the position sensor signals can be output PWM signal. drives power transistor turn-on,so as to control rotation of the brushless DC motor.In the system software design,system used C language to program, and the whole control system's software is composed of initialization module procedures, power control PWM module procedures, motion feedback module procedures, A / D sampling module procedures and PID algorithm calculation module procedures. They complete the functions of chip initialization, variables initialization, PWM generation, rotor position detection, A / D sampling, and digital PID control.The design of brushless DC motor drive control system simple structure, good performance and facilitate debugging.The system uses the speed and current double closed-loop control structure, in particular the use of motor position sensor to achieve the speed of feedback, simplifies the system structure,has a certain innovative.