Model of an Ironless Axial Flux Permanent Magnet Motor Based on the Field Produced by a Single Magnet

Abstract

The Lorentz force law is proposed as an alternative to the Maxwell stress tensor to calculate the torque of an ironless AFPM motor. This alternative allows calculating only the magnetic field produced by magnets. A model of this field based on the field produced by one magnet, the superposition principle and geometric transformations is proposed. The method is validated by full 3D FEA simulations and experimental measurements performed on a test bench.

Ironless Axial Flux Wind Turbine Motor with Two Cylindrical Magnet Rings

“…The conductors can be assimilated to a wire if the open circuit magnetic field is uniform in the coil volume. This can be the case for the motor topology with two rotors [10] [16]. For other ironless motor topologies, such as the prototype of this article, the open circuit magnetic field changes from nothing to everything in the volume of the coils.…”

“…To calculate the performance of this motor before and during its design phase, a field calculation model is used [16]. This model allows to quickly know the open circuit magnetic field of the motor whatever the geometry of the magnets and conductors.…”

“…The motor performance is calculated from the dimensions imposed by the selected magnets and corresponding coils. Methods specifically developed for ironless motors [16] are used to calculate the output performance. There are then validated by 3D Finite Element Analysis (FEA) methods and experimental measurements.…”

“…= 𝑅 + 𝑅 (9) The open circuit magnetic field is also recomposed with the method used in [16]. This time, the reference magnet is merged with one of the rotor magnets.…”

Analytical Design Methodology for Wind Power Permanent Magnet Synchronous Generators

“…Two case studies for local manufacturing of small-scale WECS based on AFPMGs are presented in [11]. Coreless AFPMGs based on additive manufacturing have been also investigated for local manufacturing, both in its doublerotor [12] and single-rotor [13] versions. In [14] the RFM and AFM are compared for micro-wind-turbine applications and the analysis shows that the RFM exhibits lower active materials cost than the AFM.…”