Position Control of a Sensorless Stepper Motor

In this paper, the experimental results of position control of the hybrid stepper motor without a mechanical sensor are exhibited. Use of the steady-state extended Kalman filter to estimate the mechanical variables of the motor is shown. With this method the computing time is reduced. The initial rotor position is estimated by the impulse voltage technique. For position control, a simple state feedback control that can compensate the load torque variations was designed. The robustness against the motor parameters variation was also studied. A field-oriented control strategy is chosen. It is known that the mechanical position is crucially important to achieve this strategy. Finally, favorable experimental results are shared.