Objectives

In highly saturated machines, magnetic forces occur inside ferromagnetic material and using lumped magnetic forces based on airgap Maxwell stress tensor might be less acurrate in certain e-motor topologies.

This module of MANATEE software specialized in magnetic noise and vibration simulation therefore computes local magnetic forces with one of these methods:

• Virtual Work Principle method on a 2D mesh (e.g. from MANATEE coupling with FEMM) or 3D mesh (e.g. from flux distribution import)
• Maxwell tensor surface forces at the interface iron/air

Summary

Magnetic forces are computed based on the electromagnetic field solution following two methods:

• air-gap Maxwell Tensor (MT) extrapolated at the iron/air interface (compatibility with all electromagnetic models) to obtain surface density forces
• Virtual Work Principle (VWP) at every node of the electromagnetic mesh (not compatible with analytical PMMF or subdomain models) to obtain nodal forces in the volume of magnetic materials, including magnets

Example of local magnetic force calculation using MANATEE

Graphical post-processing

The complete list of plot commands is available on MANATEE plot commands webpage.

How-to’s

TBC

References

• Comparison of main magnetic force computation methods for noise and vibration assessment in electrical machines