摘  要：通过调整脉宽调制信号的占空比，构造出振幅按一定规律衰减的正弦驱动电流。将该电流以一定的相位差加在步进电机的各绕组上，就能让步进电机以微步方式驱动，而且其转矩按期望的规律衰减。此方法应用于步进电机归零过程，可以使电机以恒定转速且转矩逐渐减弱的方式回到零位，有效地保护了电机和传动机构。该方法无需硬件电路，因此具有广泛的应用领域。实验结果表明，该方法使电机归零可靠，电机运行平稳。
关键词：步进电机；归零；微步驱动；脉宽调制；渐变转矩

Abstract: By adjusting the duty cycle of PWM,the sinusoidal winding current that amplitude is decreased according to some rule can be constructed.If this current is applied to the windings of step motor in certain phase difference,the motion mode of a step motor is microstepping and the torque is decreased as expected.By using this method,the step motor can return to the reference position in the manner of constant speed and gradually decreased torque,and the step motor and transmission mechanism can effectively be protected. This method doesn’t need any hardware,so it can be widely applied to many filed.The results show that the reference finding is reliable and motion of a step motor is smooth and quiet.
Key Words: Step motor;Reference finding;Microstepping drive;PWM;Gradually decreased torque