Online Stator Resistance Tracking for Reluctance and Interior Permanent Magnet Synchronous Motors

Anisotropic synchronous motors are arousing a renewed interest in many civil and industrial applications. Compared with their isotropic counterpart, they suffer a more complex magnetic structure whose identification requires the knowledge of the stator resistance. While there are many papers about the resistance estimation, it is fair to say that most of them either require the knowledge of other parameters or do not meet the specifications on accuracy and online tracking. This paper proposes a new injection-based method for the online estimation and tracking of the stator resistance, especially suited for anisotropic motors. The usual injection procedure is reversed, i.e., there is a current injection followed by a voltage measurement. It is demonstrated that the method features a resistance measurement with an improved signal-to-noise ratio and does not involve the a priori knowledge of any other motor parameter. The method can be easily applied to any kind of synchronous motor. This paper includes both the mathematical foundations and several experimental results on a laboratory prototype.