Novel sensorless speed and position detection for permanent magnet linear synchronous motor drive system

In order to implement sensorless control for permanent magnet linear synchronous motor(PMLSM),speed and position of the motor must be estimated without mechanical sensors.In this paper,a novel sensorless po-sition and speed detection algorithm is designed for PMLSM by only measuring terminal voltages and currents.This algorithm is developed from the dq estimating model of the motor,which is Park change from the three-phase volt-age model of the motor.Then two q-axis current derivatives are calculated by the estimated model and the measur-ing current signal respectively.The loop observer is done using the difference between the two current derivatives and the position is obtained by integrating the speed.Further,the algorithm is simple to implement.Experimental results show that the algorithm can estimate speed and position of the motor and its accuracy can satisfy the servo re-quirement.