*5.3. Model Selection Approach*

The selection of the electromagnetic simulation model of the IM to be used for the described field of application of a coupled electromagnetic-thermal operating point simulation is performed automatically with the presented approach of the model selection. The output quantities and effects to be investigated to describe the problem and the required levels of detail are shown in Table 1. A required level of detail of, for example, 25% means a maximum permissible deviation of 25% from the T-FEM. The required level of detail of the ohmic and stator and rotor losses is obtained assuming a measurement deviation of 5% and a deviation of the electromagnetic reference model, the transient FEM, of 10%. The level of detail of the iron loss components was chosen to be 25% because they have lower losses compared to the ohmic losses at the considered operating point. The required level of detail of the saturation was chosen to be 5 on the subjective point scale, which corresponds to the middle value of the scale. A saturated point in the efficiency maximum of the machine is selected as the operating point to be investigated. With a speed of 3700 rpm and a torque of 60 Nm, this lies in the limit between the base speed and the field weakening range of the IM.


**Table 1.** Required level of detail of the output quantities and effects of the electromagnetic model.

The model resulting from the procedure, which can represent both the range of values and the required levels of detail, is the E-HWM. The TH-FEM and T-FEM also meet the desired levels of detail, but were not chosen due to the higher degrees of freedom and associated higher computational effort.
