3‐D magnetic equivalent circuit model for a coreless axial flux permanent‐magnet synchronous generator

Abstract

In coreless axial flux permanent magnet synchronous generators (AFPMSGs), magnetic leakage and fringing effect is significant due to the large air gap and increases the difficulty in magnetic field calculation. This paper presents a 3‐D magnetic equivalent circuit (MEC) model for the magnetic field calculation in coreless AFPMSGs by considering the magnetic leakage and fringing flux. Field distribution is calculated based on the magnetic circuit analysis. The magnetic flux in the air gap between the permanent magnets is analysed using the magnetic field division method. Compared with the traditional magnetic circuit model, the magnetic leakage from PM to the rotor iron plates is considered in both radial and tangential directions in the proposed model. The proposed MEC method is applied to a specific AFPMSG, and the magnetic field distribution, no‐load back electromotive force (EMF), and torque are calculated and compared with finite elements (FEM) results. AFPMSG machines with different pole‐arc ratios are prototyped to validate the effectiveness and accuracy of the proposed 3‐D MEC model. The results obtained by the proposed MEC model are in good agreement with those of the FEM and experimental results.

A systematic review on current research and developments on coreless axial‐flux permanent‐magnet machines

“…In Ref. [15], coreless AFPMSG machines with different pole-arc ratios were prototyped to validate the efficiency of a 3D magnetic equivalent circuit (MEC) model through magnetic field distribution, no-load back EMF, and torque. In Ref.…”

“…F I G U R E 4 Different prototype coreless machine implementation. (a) Rotor oriented design [14], (b) pole arc ratio implementation [15], (c) integrated coil design [16] (d) rotor thickness optimisation [17] (e) magnet shape variation [18] and (f) single stator double rotor machine [19] F I G U R E 5 Search criteria and protocol of the systematic literature review…”

“…In Ref. [15,45], a 3D MEC model for the magnetic field calculation in coreless SSDR AFPMSG was presented by considering the magnetic leakage and fringing flux. A quasi-3D analytical model for SSDR coreless AFPMMs was discussed in Ref.…”

“…In Ref. [15], the influence of magnet shape on the performance of a coreless stator AFPM machine has been presented. A study proposes design optimisation of a coreless stator for small scale portable applications in Ref.…”

“…In Refs. [15,44,46,48,105], researchers applied non-overlapping windings in coreless stators, claiming high performance due to optimised winding for the coreless machine. However, in Ref.…”