Design And Research Of A Controller For The Permanent Magnet DC Brushless Motor

Rare earth permanent magnet brushless DC motor is a mechanical and electrical integration motor, composed by the body of permanent magnet motor and controller. The rotor of permanent magnet brushless DC motor uses rare earth permanent magnet with no excitation loss, the armature current controlled by circuit controller to achieve the non-contact reversing. Rare earth permanent magnet brushless DC motor possessed both the strong mechanical structure of AC motor, and excellent speed characteristics of DC motor, is a variable speed motor to run more efficient than other types, whether run in high or low speed.Permanent magnet brushless DC motor operated by electronic commutation, compared with a brush DC (mechanical commutation) motor has low noise, no spark interference, high efficiency and long life characteristics. This paper introduces the basic structures and working principles of the permanent magnet brushless DC motor, and direct torque control technology applied in DC brushless motor,and also analyzes both steady-state and start-up operating characteristics for DC brushless motor, and gives Analysis of the hardware controller for completing electronic commutation with the microcontroller and the speed control function, which uses software to achieve the rotor position detection, rotation magnetic field signal output and PWM motor speed control.Design results show that the DC brushless motor control system designed by MCU core has a simple structure, wide speed range, low noise, high power density, large starting torque and long service life, so that the DC brushless motor are more and more widely used in our daily life.