Influence of the air-gap permeance harmonics on the performances of the salient pole synchronous PM machines

In this paper the theory of the salient pole synchronous PM machines further is investigated and extended. Since the theory of this type of electric machines until now is based only on the idealized machines (with sinusoidally variation of the air-gap length), the main motivation of this work was to investigate the influence of the air-gap length (rotor permeance effect) on the performances of this type of machines. Using the correct expression for the effective air-gap length the effect of the air-gap permeance harmonics on the self-, mutual and phase inductance and also on the current flux-linkage, is investigated and analysed.