Improved rotor models for vector controllers

Variations in motor model parameters lead to the detuning of vector controllers which, in turn, causes a deterioration in performance, particularly during transient and field weakening operation. Parameter adaptation schemes seek to change the model parameters based on observed performance, but are still based around a simple model for the machine which is not adequately representative. Improved motor models, based on deeper phenomenological understanding of the machine offer a viable alternative. In this paper the authors present a model which enables rotor leakage and main flux path saturation and deep-bar effects to be taken into account. The model is verified experimentally using a 7.5 kW 4-pole motor, mounted on a piezo-electric force table which enables transient torques to be measured.