Prediction of the magnetic field in the air-gap of synchronous machines on a preliminary design level — Machine modelling and field calculation

A method is introduced, which uses analytical field calculation to predict the distribution of the magnetic air-gap field of an electric machine at an early stage of design. In this paper the underlying boundary value problems are formulated and solved for a machine configuration which is held as general as possible. Focus is laid on an easy implementation and high adaptivity of presented formulae. In combination with conformal mapping, which is not discussed in detail within this paper, the method is applicable to various kinds of electric machines. These are electrically excited synchronous machines with and without salient poles, permanent magnet synchronous machines with surface magnets and induction machines (not discussed). Results of the calculation and possible utilisations are presented.