Abstract
Dc motor plays an important role in all walks of life, and motor speed is one of the important performance indicators. With the development of science and technology, PWM speed regulation becomes a way of motor speed regulation. Because of motor is widely used in automobile industry, this design at this point, based on freescale series are widely used in automobile industry S912XET256J2MAA chip of dc motor drive system for research, mainly through S912XET256J2MAA and BTS7960 chip controlled PWM dc motor speed control system, by changing the PWM duty cycle to change the rotating speed of dc motor. Displacement sensors are used in this system the data, the dc motor speed regulation, can make the motor according to the depth of the displacement sensor, in turn, determined by the linear relationship between rotating speed, implementation of acceleration and deceleration control of dc motor.