A 2-D-Based Analytical Method for Calculating Permanent Magnetic Ring Bearings With Arbitrary Magnetization and Its Application to Optimal Bearing Design

Combined radial-axial magnetic bearings (MBs) use a common bias magnetic circuit to provide radial and axial bias magnetic flux. Different from separate MBs, there is a constraint relation between the radial and axial bias flux. Meanwhile, there is also a constraint relationship between the radial and axial maximum bearing capacity. Therefore, the design method for separated MB is not suitable for a combined radial-axial MB (CRAMB). In this study, a design method of the CRAMB based on an asymmetric factor was proposed. The definition of the asymmetric factor was proposed. In order to avoid the radial and axial magnetic flux into the weak magnetic field and saturation region, the optimum range of the asymmetric factor is analysed. The influence of the asymmetry factor on stiffness is analysed; the prototype designed by this method can run stably. The validity and accuracy of the design method are verified by experimental results.

Section: Introductionmentioning

confidence: 99%

Analysis and design method of a combined radial–axial magnetic bearing based on asymmetric factor

Ren

Sun

Peng

et al. 2019

“…Marth et al [4] have investigated the optimal design of passive magnetic bearings with arbitrary magnetisation patterns to maximise the stiffness per magnet volume ratio by using a 2D analytical model. In addition, the influence of the design parameters such as geometry, magnetisation, and stacking number on maximum material utilisation has been studied.…”

Section: Introductionmentioning

confidence: 99%

2D analytical model for heteropolar active magnetic bearings considering eccentricity

Shakibapour¹,

Rahideh²,

Mardaneh³

2018

This study presents a 2D analytical model for heteropolar active magnetic bearings. In this method, the problem is divided in to three subdomains: slots, slot-openings and air-gap regions. Initially, the radial and tangential components of the flux density vector are analytically presented in the absence of eccentricity. Then the impact of various amounts of eccentricity is investigated. Finally, the magnetic local traction and magnetic forces exerted to the rotor along x and y directions are calculated. The comparison between the proposed analytical model and the finite-element method shows the efficacy of the model.

“…The stiffness of an axial or radial magnetic bearing can be calculated in three-dimensional (3D) space by using the equivalent magnetic charge model, which results in uncomfortable formulas [1][2][3]. If the mean air gap radius is considerably larger than the air gap length, 2D analytical model can be used for stiffness calculation [4,5], as the method named planer model by Marth et al [5]. The stiffness of magnetic bearing composed of only two permanent magnet rings is very low.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive comparison of different structures of passive permanent magnet bearings

Safaeian

Heydari

2017

Here, different feasible configurations of passive permanent magnet bearings (PMBs) are presented and compared with each other. In these configurations, stiffness is improved by adding iron cores and air intervals between magnets. Bearings with opposite magnetisation stacking (standard) and rotating magnetisation stacking (Halbach) are studied here. A twodimensional planner model is used to calculate the magnetic field and stiffness. The optimisation will be performed for obtaining maximum stiffness per magnet volume ratio. The results show that standard stacking with radially magnetised PMs and having back iron and air intervals between magnets is the most optimum structure. For larger dimensions of magnets, other structures will be useful too.