Estimation of Induction Motor Rotor Temperature Exploiting Intermodulation Saliency

Abstract

The extraction of the spatial asymmetries of AC motors allows to acquire meaningful information for encoderless control or fault detection. Additionally, motor saliencies can be employed to also estimate rotor temperature, which is required for the correct production of torque and flux. Owing to the strong temperature-independent feature of the motor spatial saliencies, it is possible to exploit the saliency parameters, namely amplitude and phase shift, in order to estimate rotor temperature. In this work, a multi-salient induction motor is investigated for encoderless saliency-based rotor temperature estimation. The motor shows saturation, slotting and intermodulation saliencies. The phase shift and amplitude of the induction motor saliencies are analyzed regarding temperature estimation capability. Furthermore, the intermodulation saliency is computed during online operation and processed in a control scheme that estimates the rotor temperature. Experimental validation for a traction induction motors is provided.