Precise position detection technique for permanent magnet linear synchronous motors

This paper addresses the problem of position detection for permanent magnet linear synchronous motors (PMLSM). Considering the characteristic of PMLSM, an original method based on end side magnetic field of the PMLSM is proposed. The method detects the real-time value of the magnetic field utilizing at least two linear Hall sensors which are fixed on the mover along the direction of the linear motor. The digital filtering techniques are used to deal with the magnetic field data smoothly. A farther mathematical method is developed to interpolate the normalized sinusoidal curve for improving the resolution and the precision.