An Axial-Flux Dual-Rotor Slotless Permanent Magnet Motor with Novel Equidirectional Toroidal Winding

Abstract

In this paper, a dual-rotor slotless axial-flux permanent magnet (AFPM) motor with equidirectional toroidal winding (ED-TW) is proposed and compared with the AFPM motor with traditional toroidal winding (T-TW) with the same dimensions, number of coils and poles. Different from the T-TW, only the positive sides of coils of the ED-TW are left on one side of the stator core, the return sides of the coils are all removed to the other side of the stator core. Firstly, the structure and operation principle of the two motors are introduced and analyzed. To clarify the features of the ED-TW, the synthetic electromotive force (EMF) vector and armature reaction field of the ED-TW and T-TW are studied. Secondly, the main size equations of the AFPM motors with toroidal windings are presented. Subsequently, the electromagnetic characteristics of the AFPM motors with ED-TW and T-TW are analyzed and compared based on the three-dimensional finite element method (3D-FEM). The comparison results indicate that the AFPM motor with ED-TW has superiority in torque density and efficiency. Finally, a prototype of the AFPM motor with ED-TW is manufactured and tested, which validates the feasibility of the proposed motor and the correctness of the analysis of the 3D-FEM.

Electromagnetic Characteristics Analysis of a Novel Differential Dual‐Rotor Contra‐Rotating Axial‐Flux PM Motor with Equidirectional Toroidal Winding

“…The characteristics of the equidirectional toroidal winding has been investigated in Refs. [18][19][20]. Literature [19,20] apply EDTW to AFPM motor, compare EDTW to other winding configurations and draw a conclusion that the AFPM motor with EDTW has superiority in back electromotive force (back-EMF) amplitude, torque density and efficiency.…”

“…[18][19][20]. Literature [19,20] apply EDTW to AFPM motor, compare EDTW to other winding configurations and draw a conclusion that the AFPM motor with EDTW has superiority in back electromotive force (back-EMF) amplitude, torque density and efficiency. These characteristics are suitable for ship propulsion.…”

A Review of Axial-Flux Permanent-Magnet Motors: Topological Structures, Design, Optimization and Control Techniques

“…The design and analysis of AFPM motors usually starts from performance requirements and size constraints, followed by the matching design and optimization design of parameters and finally the evaluation of the mechanical performance of the overall structure [7,47]. After years of exploration in academia and industry, the unique design and analysis methods of AFPM motors have been established.…”

A method of reducing the cogging torque in a flux-torque regulation hybrid excitation machine with axial-radial magnetic circuit

“…In recent years, with the development of rare earth permanent magnet materials, the permanent magnet (PM) machines are more and more widely used in aerospace, wind turbines, new energy vehicles and other fields [1][2][3][4]. However, due to the fixed magnetic potential source of PM machines, which limits the use of the machines in a wider speed range operation.…”