毕业设计-基于单片机的直流脉冲（PWM）调速及旋转方向控制系统设计_精品.doc

摘 要 随着时代的进步和科技的发展，电机调速系统在工农业生产、交通运输以及日常生活中起着越来越重要的作用本采用单片机与L298N驱动芯片驱动电机工作Abstract With the progress of the times and the development of science and technology, motor speed control system in the industrial and agricultural production, transportation and daily life plays an increasingly important role in. DC motor is accomplished by a two magnetic field interactions which occur rotation. The stator by permanent magnets or stimulated the electromagnet produces a fixed magnetic field, the rotor is composed of a series of winding and the magnetic materials formed, the current through each winding will generate a magnetic field. The brush DC motor, rotor and stator of the commutator brush in the motor rotates for each winding supplies electrical energy. Energized rotor winding and the stator magnets have opposite polarity, through attraction to produce torque rotating the rotor. The speed of the motor and the applied voltage is proportional to the torque is proportional to the current, and the. For the DC motor control is a challenge, because must be at work during changing the speed of DC motor. The DC motor is the efficient operation of most commonly used method is applied to a PWM ( pulse width modulation ) square wave, the on-off ratio corresponding to the desired speed. The motor has a low pass filter function, it will PWM signal is converted to an effective level. The design of STC89C52 monolithic integrated circuits to control the PID the direct pulse （PWM ） machinery velocity modulation system, and elaborated on the system of control methods, structure and design, the application design problems. the system simple and good performance machinery velocity modulation prices are high, really to direct the electrical machinery velocity modulation control system of high-precision. Key words：monolithic integrated circuits, a direct motor, machinery velocity modulation system 引言 4 1 系统硬件介绍 4 1.1硬件主控芯片概述及功能介绍 4 1.1.1 STC89C52单片机主控制电路图 4 1.1.2 L298N直流电机的专用驱动器 5 1.2 硬件电