本课题是对直流电机PWM调速器设计的研究，主要实现对电动机的控制。因此在设计中，对直流调速的原理。，在设计中，采用了AT89C51单片机作为整个控制系统的控制电路的核心部分，在设计中，采用PWM调速方式，通过改变PWM的占空比从而改变电动机的电枢电压，进而实现对电动机的调速。-This topic is a DC motor PWM speed controller design study, the main achievement of motor control. Therefore, in design, the principle of the DC converter. In the design, using AT89C51 microcontroller as the control system the core of the control circuit in the design, the use of PWM speed control mode, by changing the PWM duty cycle to change the motor armature voltage, so as to realize the motor' s speed.