Design of a reluctance synchronous machine for saliency based position sensorless control at zero reference current

The saliency dependent position sensorless control capability of reluctance synchronous machine (RSM) drives is investigated in this paper. High frequency injection position sensorless control methods rely on a large enough saliency to track the electrical angle. The RSM has a large saliency within its rated operating regions making it ideal for high frequency injection position sensorless control. It is shown, however, in this paper that the RSM has a limited saliency magnitude at low current, limiting its position sensorless control capability. Design modifications are suggested to increase the saliency of the RSM at zero reference current, thus increasing the drive´s position sensorless control capability. These modifications are simulated in a FE package, built and evaluated. The effect of rotor skewing on the position sensorless control capability of the RSM is also evaluated by means of a FE package. A RSM with a skewed rotor is tested to confirm simulation results.