A Novel Method for Calculating Airgap Permeance of PM Machines Based on Equivalent Electrostatic FEA

摘要

The detailed airgap permeance distribution of an electric machine is important information for analyzing and optimizing the machine's performance. However, there is only analytical method to calculate permeance, and the simulation method which can be used to validate the analytical method for permeance is not given. In this paper, a novel simulation method for investigating the airgap field of PM machines is proposed based on the duality of magnetic field and electric field. Through equivalent electrostatic finite element analysis (FEA), the airgap permeance of the PM machine can be easily determined. The obtained permeance distribution can then be associated with analytical form of magnetomotive force (MMF) to further calculate the airgap flux density. The proposed method can take the stator slotting effect into account, and its effectiveness is validated on a vernier PM machine. Finally, the reasonability of the method on calculating airgap permeance is verified through comparison with a proposed 3D electromagnetic FEA.