[摘要]由于直流电机具有起动转距大，体积小，重量轻，转距和转速容易控制以及效率高等十分优良的特性。本文针对直流电机的特点，根据自动控制原理，采用PWM控制方式，设计了直流调速脉宽调速系统以更好地控制直流电机的速度。
本文介绍了基于单片机用PWM实现直流电机调整的基本方法，直流电机的相关知识，及PWM调整的基本原理和实现方法。重点介绍了基于89C51单片机的用软件产生PWM信号的途径，并介绍了PWM占空比调节的方法。对于直流电机速度控制系统系统的实现提供了一种有效途径。
系统以89C51单片机为核心，以小直流电机为控制对象，实现速度单闭环，PID控制，方便的人机对话接口，用键盘输入有关控制信号及参数，可以实现电机的启制动，正反转，速度调节，并在LED上实时显示是如参数及动态转速，采用单片机控制取代了以往的模拟控制，无零点漂移，使控制精度更高，而且方便系统的改进和升级，灵活性和适应性更强。
[关键词]单片机系统 PWM 直流电机调速
Direct current machine speed control system design
This paper introduces a kind of method of DC-motor speed modification based on PWM theory by the SCM. Showing some relative knowledge upon the DC-motor timing,the basic theory and the way to implement. And it emphasizes on the way or carrying out PWM signals based on MCS-51. This paper still provides a method for modifying the speed of DC-motor by way of taking count of data and time delay by software. It offers a sort of efficient method for the DC motor speed-controlling system.
A kind of PWM direct current motor speeding control system was introduced based on Singic Chip Micyoco control. Taking 89C51 Single Chip Micyoco as core and the little direct current motor as control object,the single closed loop speed control were realized. In the convenient man-machine interaction interface, the contol signal and parameter were iputted with keybaord so that the start and brake of motor,pros and cons turn and speed regulation were also realized. The input parameter and dynamic rotational speed can be shown on LED with real time. The former simulated control was replaced by Single Chip Micymoco control, which not only made the control precision higher without zero shift,but also facilitated the systematic improvement and upgrading,with flecibility and adaptability enhenced.
