An application of observer for position sensorless stepper motor drives

Abstract

A control method for stepper motor drives system can be made in open-loop circumstance which mean the system control did not require any feedback input signal in order to run the system. By applying the right sequences of pulses, the stepper motor capable to operate as other motion control. However, the performance of such system cannot be achieved to high level condition and demanded a feedback signal input to compensate the error produced while running the drive system. Therefore, a physical sensor or an encoder is placed in the motor system to obtain the feedback and form a close-loop system for error compensation. Nevertheless, the prices of these instruments are expensive, bulky and also may degrade the system performance. As a result this project presents a sensorless system in stepper motor drive system as an alternative to develop a close-loop system where the input signals are taken from voltage and current of the magnetic flux of the stepper motor.