Mixing 2D with 3D finite elements in magnetic models

Two-dimensional air-gap elements are shown to allow accurate magnetic-field calculation when placed in a vector potential finite-element model of a three-dimensional device containing steel. Two-dimensional conducting elements are also shown to be useful in three-dimensional magnetostatic problems. The two-dimensional elements reduce the number of grid points and hence the modeling and solution times. Changing element thickness is made much simpler than with all three-dimensional elements. Example models and calculated magnetic fields are shown for a simplified three-dimensional claw-pole alternator model with all three-dimensional elements as compared with two-dimensional air-gap elements. Another example uses two-dimensional conducting elements to create three-dimensional magnetic fields.>