Stability- and Sensitivity-Analysis of a Sensorless Controlled Synchronous Reluctance Machine using the Back-EMF Model

摘要

In this paper the position sensorless operation of a synchronous reluctance machine (SynRM) in the medium and high speed range is discussed. The Back-EMF method is the commonly used sensorless method in this speed range. It estimates the flux-linkage of the synchronous motor which is rigidly connected to the rotor position. In the case of the SynRM without permanent magnets the flux-linkage is only caused by the stator current, which leads to a high dependency of the Back-EMF method on the operating point. This results in the fact that no optimal MTPA-operation of the machine is possible, because of stability issues of this sensorless method. In the following work, the stability and the sensitivity to parameter fluctuations of the Back-EMF method is analysed dependent on the current-angle in the rotor fixed reference frame.