Separating anisotropic material effects in the control signals of inverter-fed AC machines

In the non-model-based mechanical sensorless control of AC machines the flux/rotor position can be estimated by evaluating the current response to voltage pulses. This current slope is modulated by all spatial saliencies in the machine. Sources of these saliencies can be various, for instance the saturation of the machine by the main flux, the slotting, lamination material anisotropy as well as eccentricity. Measurements are performed on specially designed machines enabling the separation of the effects of material anisotropy as well as eccentricity in the current slopes