3-DIMENSIONAL MAGNETIC-FIELD COMPUTATION BY A COUPLED VECTOR-SCALAR POTENTIAL METHOD IN BRUSHLESS DC MOTORS WITH SKEWED PERMANENT-MAGNET MOUNTS - THE FORMULATION AND FE GRIDS

A three dimensional finite element (3D-FE) method for the computation of global distributions of 3D magnetic fields in electric machines con taining permanent magnets is presented. The formulation of this 3D-FE method including 3D permanent magnet modeling, which is based on a cou pled magnetic vector potential - magnetic scalar potential (CMVP-MSP) approach, is given. The development of the necessary 3D-FE grids and a lgorithms for the application of the method to an example brushless dc motor, whose field is three dimensional due to the skewed permanent m agnet mounts on its rotor, is also given here. A complete set of resul ts of application of the method to the computation of the global 3D fi eld distributions and associated motor parameters under no-load and lo ad conditions are detailed in a companion paper.