基于单片机的PWM直流电机调速系统毕业论文.doc

摘要 在如今的现实生活中，自动化控制系统已在各行各业得到广泛的应用和发展，其中自动调速系统的应用则起着尤为重要的作用。虽然直流电动机不如交流电动机那样结构简单、价格便宜、制造方便、容易维护，但是它具有良好的起、制动性能，宜于在广泛的范围内平滑调速，所以直流调速系统至今仍是自动调速系统中的主要形式。现在电动机的控制从简单走向复杂，并逐渐成熟成为主流。随着电力电子技术的发展，开关速度更快、控制更容易的全控型功率器件MOSFET和IGBT成为主流，脉宽调制技术表现出较大的优越性：主电路线路简单，需要用的功率元件少；开关频率高，电流容易连续，谐波少，电动机损耗和发热都较小；低速性能好，稳速精度高，因而调速范围宽；系统快速响应性能好，动态抗扰能力强； 本设计以89C52单片机为核心，用C语言进行编程控制，采用单片机内部定时器产生可调的矩形波。以键盘作为输入达到控制直流电动机的启停、速度和方向，电动机速度的测量，在设计中，依据直流电动机的工作原理和数学模型以及脉宽调制（PWM）控制原理和H桥电路基本原理设计了驱动电路，采用了PWM技术对电动机进行控制，通过对占空比的计算达到精确调速的目的，通过光电对管以及码盘来测量电动机的转速，防止电动机堵转而烧坏。测量的速度通过4位数码管来显示。 关键字：PWM调速 H桥电动机驱动 电动机测速 89C52单片机 ABSTRACT With the development of science and technology, automatic control system has been widely used and development in all walks of life, which the application of the automatic speed control system plays a particularly important role. DC motor as AC motor as the structure is simple, cheap, easy to manufacture, easy to maintain, but it has a good start, braking performance, it is appropriate in a wide range of smooth speed, DC speed control system is still automatically speed control system in the main form. Motor control from simple to complex, and mature into the mainstream. With the development of power electronics technology, the switching speed is faster, easier to control the full-controlled power devices MOSFET and IGBT become mainstream, pulse width modulation technology showed a greater superiority: the main circuit line is simple, need to use the power components ; switching frequency, current continuous, harmonic, motor loss and fever are small; good low-speed performance, high-speed stability, and thus a wide speed range; rapid system response performance, dynamic immunity; The design of the 89C52 MCU as the core, using the C programming language to control, using MCU internal timer adjustable rectangular wave. Start and stop the keyboard as an input to control the DC motor speed and direction, the measurement of the speed of the motor, working principle and mathematical model of the DC