New constraint technique for 3D finite element analysis of multiturn windings with attached electric circuits

A new constraint technique for 3-D finite element models of electromagnetic devices with multiturn windings attached to electric circuits is presented. The new technique is easily applied to any 3-D winding shape. The example 3-D transformer has resistors on both its primary and its multiturn secondary windings and high core permeability. Applying the new technique yields winding currents that agree with ideal transformer theory. Additional analyses are made with various linear and nonlinear core materials and differing winding shapes