Cogging Torque Mitigation in Axial Flux Magnetic Gear System Based on Skew Effects Using an Improved Quasi 3-D Analytical Method

Abstract

Since the flux leakage phenomenon is dominant in the inner and outer radii of axial flux magnetic gears (AFMGs), a prominent over estimation of torque prediction is obtained by 2D analytical method (AM) in comparison with 3D finite element method (FEM) simulations. The main motivation of this study is to present an improved quasi 3D analytical method (IQAM) which is an improvement and amendment of the 2D AM by a simple and effective radial dependence modeling of the axial and tangential magnetic field distribution in AFMGs This IQAM plays an important role in reliable and accurate prediction of static and transient behavior of AFMGs. Using the obtained IQAM and Maxwell's stress tensor, cogging torque of the AFMG is predicted. However, the proposed IQAM will become more prominent by focusing on the effects of single-and dual-skews' designs for ferromagnetic pole-pieces and PMs through suitable step changes in a combined skewed MG model, as an effective passive method, in order to mitigate cogging torque and thereby intensively augmenting torque quality in an exemplary AFMG. The accuracy of the developed skewing method is verified using 3D FEM simulations.Index Terms-quasi 3D analytical method, magnetic gear, axial flux, cogging torque, skew effect, 3D FEM. 0018-9464 (c)

Electromagnetic Vibration Simulation of a 250-MW Large Hydropower Generator with Rotor Eccentricity and Rotor Deformation

“…The flux is produced by the centric rotor with no load. The maximum magnetic flux density is near to 0.7 T. The shape is similar to the sine wave, and it can be easily observed that the slots and teeth on stator cause the distortion of the radial flux density wave [16]. Figure 10 presents the radial flux density distribution on the surface of the stator teeth over all of the poles.…”

Design of an Axial-type Magnetic Gear with Auxiliary Flux-enhancing Structure

“…Despite these advancements, the design faced limitations in significantly boosting gear torque and exhibited magnetic leakage in slower-rotating rotors. Furthermore, the performance evaluation of AMGs necessitates the construction of complex three-dimensional models, a process that is notably time-consuming and has thus limited the proliferation of research and development in this area [24,25]. The axial-direction force exerted by AMGs also poses substantial challenges to their fabrication, complicating the design process further.…”

A review on the field‐modulated magnetic gears: Development status, potential applications, and existent challenges

“…Hence, some methodologies used to improve operational performance of the radial‐flux FMMG can be also applied to the axial‐flux FMMG. For instances, skewing or pole pairing can be used to realize torque‐ripple depression [76, 77] and the Halbach PM array is effective to elevate the torque density [78].…”