Enabling sensorless control of a permanent magnet synchronous machine in the low speed region using saturation

In this paper the sensorless control of a permanent magnet synchronous machine which is meant to be used in pump applications is discussed. The sensorless control in the middle and high speed region can be considered as state of the art. In contrast to that, sensorless control in the low speed region for use in industrial applications still is an issue. Therefore, this paper focuses on saliency based sensorless control employing high frequency signal injection which usually is applied for low speed applications. However, it is shown that the used machine does not provide the required properties for such kind of sensorless control. Therefore, a new strategy is presented which compensates for the insufficient properties regarding position estimation in order to allow a saliency based approach anyway.