《高精度步进电机控制系统的研究》-毕业论文.doc

PAGE w w 摘 要 步进电机是一种将电脉冲信号转换为角位移的执行机构，步进电机的主要优点是有较高的定位精度，无位置累积误差，并且特有的开环运行机制，与闭环控制系统相比减少系统成本，提高了可靠性，在数控领域得到了广泛的应用。但是，步进电机在低速运行时的振动、噪声大，在步进电机的自然振荡频率附近运行时易产生共振，输出转矩随着步进电机的转速升高而下降，这些缺点制约了步进电机的应用范围。 步进电机的使用离不开步进电机驱动器，步进电机的运行性能与步进电机驱动器的优劣密切相关。传统的驱动方式偏重使步进电机绕组电流以尽可能短的时间上升到额定值，从而提高电机高速运行时的转矩，造成低速运行时的振动和噪音加大。并且为满足用户对不同步距角的要求。 本文在调研各种驱动技术的基础上，设计实现了基于电流追踪型脉宽调制(PWM)技术的多细分两相混合式步进电机驱动器，包括硬件设计、软件实现。正弦电流细分技术基本上克服了传统步进电机低速振动大和噪音大的缺点，减小发生共振的几率。电流追踪型脉宽调制(PWM)技术使电机运行在较大速度范围内转矩保持恒定。以满足不同用户和不同电机的要求,该驱动器的功率驱动部分使用NMOS智能功率模块，提高了驱动器可靠性。 驱动器细分运行时减弱了混合式步进电机的低速振动，电机运转平稳，大大减轻了噪声;同时该驱动器具有较小的体积、较低的成本和较高的可靠性。 关键词: 混合式步进电机 细分驱动器 脉宽调制 Abstract The stepper motor is an electromechanical device that converts electrical pulses into discrete mechanical movements. The advantages of stepper motor are precise positioning and non-cumulative movement error from one step to the next. Compared to closed loop control, open loop operation of stepper motor is more reliable and less expensive. The disadvantages in using a step motor are vibration and noise at low speeds, resonance when the motor is operated at or around the natural resonance frequency, motor torque decreasing with speed increasing. These disadvantages limit step motors application. Step motor cannot work without step motor driver. Its performance is close related to stepper motor driver. Traditionally, a motor driver is to provide the rated current to the motor windings in the shortest possible time, helping to maintain high speed torque. As a result, motors vibration and noise is greater at low speeds. Otherwise, many types of step motor and driver have to be produced in order to satisfy customers need for different step angles After study many kinds of driver technology, a microstepping driver for two-phase hybrid stepper motor has been designed. The driver adopts sine wave current subdividing and current tracking PWM technology. Sine wave current subdividing technology not only overcomes the disadvantages of motors vibration a