Permanent Magnet Motor in 3D

Application ID: 47621


Permanent magnet (PM) motors are used in many high-end applications, such as in electric and hybrid vehicles. An important design limitation is that the magnets are sensitive to high temperatures, which can occur through heat losses caused by currents, particularly eddy currents.

In this tutorial, an 18-pole PM motor is modeled in 3D to accurately capture eddy current losses in the magnets. The central part of the geometry, containing the rotor and part of the air gap, is modeled as rotating relative to the coordinate system of the stator. Sector symmetry and axial mirror symmetry are leveraged to reduce the computational effort while still capturing the full 3D behavior of the device.

An additional dependent variable is used to compute and store the time integral of the eddy current loss density in the magnets. This could be used later as a distributed time-averaged heat source in a separate heat transfer analysis, where the thermal time scale is typically much larger than that of the eddy current losses.

You can learn more about this example in a related blog post: "Capturing Eddy Current Losses in a Permanent Magnet Motor Design".

This model example illustrates applications of this type that would nominally be built using the following products: