Proposition of new mathematical models with stator core loss factor for induction motor

Abstract

This paper proposes new mathematical models with stator core (iron)‐loss factor for induction motors intended to generate precise and/or efficient torque via vector control. The proposed models have a structure in which the stator core‐loss resistance is equivalently placed purely in parallel with the stator inductance. It is shown that stator core losses consisting of eddy‐current and hysteresis losses can be properly represented by the parallel resistance, and, in particular, eddy‐current loss by a constant one. The models are composed of three basic vector equations in the general frame of an arbitrary angular frequency, such as fourth‐order differential equations describing motor dynamics, the torque equation, and the energy conversion equation. These basic equations are essential for vector control design taking core loss into consideration. The proposed models are most compact in the sense of the number of both the employed parameters and the interior states of the motor. Compactness is an important factor for modeling and is useful for designing vector control systems. © 2000 Scripta Technica, Electr Eng Jpn, 134(1): 64–75, 2001

Inclusion of hysteresis and eddy current losses in dynamic induction machine models

“…The iron losses mostly consist of the hysteresis losses, the eddy current losses being less than 1% of the total losses at the low frequency considered. In [3], a nonlinear resistor depending on the instantaneous angular frequency of the stator flux is used to model the iron losses. If this resistor would be used, the iron losses would be zero as the stator flux vector does not rotate.…”

“…Hence, the frequency dependency corresponds to that of the eddy current losses. In [3], the hysteresis losses are modeled by a nonlinear resistor depending on the instantaneous angular frequency of the stator flux. The model can predict the hysteresis losses if the magnitude of the flux vector is constant, but it fails to predict the losses caused by the pulsating flux magnitude.…”

Dynamic model of a self-excited induction generator with fundamental stray load and iron losses

“…However, in this way the number of the first-order differential equations describing the IM is increased by two compared to the conventional model. This problem can be circumvented by shifting the iron-loss resistance in front of the stator leakage inductance, as first proposed by Shinnaka in [11]. The Shinnaka configuration was later considered and experimentally verified in [4,12,13].…”