Magnetic Fields and Forces in Permanent Magnet Levitated Bearings

Bachovchin, Kevin; Hoburg, James F.; Post, R.F.

doi:10.1109/tmag.2012.2188140

Cited by 35 publications

(24 citation statements)

References 7 publications

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“…Meanwhile, differential control method has often been adopted [14][15][16][17][18][19][20]. Because the force between the stator and rotor is always an attractive force in an active magnetic bearing (AMB), when the rotor is located in the center position without control current, the attractive forces of two magnetic bearings are the same in the opposite directions.…”

Section: Introductionmentioning

confidence: 99%

Integrated Design and Optimization Method of an Asymmetric Hybrid Thrust Magnetic Bearing With Secondary Air-Gap

Ren¹,

Le²,

Wang³

2017

PIER B

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Abstract-In this paper, an asymmetric thrust magnetic bearing (MB) design principle and method are introduced. Different from the general design method of magnetic bearing, the asymmetric magnetic bearing design method focuses on the effect of asymmetric factor. A permanent magnet biased asymmetric hybrid thrust magnetic bearing (AHTMB) with secondary air-gap is designed in detail. A multi-objective optimization is conducted with genetic algorithm (GA) to get smaller mass and less loss. According to optimized model parameters, magnetic field distribution, stiffness and effect of asymmetry factor on stiffness are also analyzed. For stability of the system, equivalent stiffness and equivalent damping and current characteristics are deduced. Based on the analysis results and design methods, appropriate asymmetry factor asymmetric can be chosen to satisfy the different bias force requirement. With small number of coils and current, AHTMB with secondary air-gap is beneficial for decreasing the copper loss and enhancing dynamic performance of control system.

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Section: Introductionmentioning

confidence: 99%

Integrated Design and Optimization Method of an Asymmetric Hybrid Thrust Magnetic Bearing With Secondary Air-Gap

Ren¹,

Le²,

Wang³

2017

PIER B

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“…Due to the advantages of high speed, no friction, high precision and long service life [1][2][3][4][5], magnetic bearings play an important role in electric drives working under high speed, vacuum and clean conditions. They have been applied in rotating machinery applications like motorized spindles, agile satellites and flywheel systems [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Modeling for Three-Pole Radial Hybrid Magnetic Bearing Considering Edge Effect

Zhu¹,

Shuling²,

Jv³

2016

Energies

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Abstract:In order to overcome the shortcoming of magnetic bearings whereby general mathematical models of the radial suspension forces cannot be accurately established, a mathematical model considering the edge effect is set up. The configuration, operation principle and flux distribution features of a three-pole radial hybrid magnetic bearing (HMB) are analyzed in this paper. The magnetic field division method is employed to calculate the permeance of different regions around the end portion of poles. The total permeance of a single pole is composed of the permeance of the regions. Then, an accurate mathematical model of the radial suspension forces considering the edge effect is deduced by the equivalent magnetic circuit method. From the modeling procedures, it can be seen that the edge effect calculation is only related to the configuration and parameters of the magnetic poles, and is isolated with the other configurations and parameters of the three-pole radial HMB, therefore, the mathematical model is proved universal for calculating different suspension forces of hybrid magnetic bearings. A finite element analysis (FEA) simulation and three-pole radial HMB experiments are performed. The error between the theoretical calculation values and the FEA simulation values of the suspension forces is less than 5%, and the error between theoretical calculation value and experimental value of suspension forces is less than 7%. The comparison between the results of the theoretical calculation, FEA simulation and experiments has verified that the established mathematical model can accurately calculate the suspension forces.

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“…Although there have been many studies on the magnetic force model of PMB and HMB in the literature [21][22][23][24][25], only few are dealing with PMB and HMB with Halbach array configuration [23][24][25]. To the best knowledge of the authors, almost no analytic magnetic force model for such system was presented in the literature, especially for the ring-type structure.…”

Section: Introductionmentioning

confidence: 99%

Design, Modeling and Control of Magnetic Bearings for a Ring-Type Flywheel Energy Storage System

Toh¹,

Chen²

2016

Energies

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This study is concerned with the magnetic force models of magnetic bearing in a flywheel energy storage system (FESS). The magnetic bearing is of hybrid type, with axial passive magnetic bearing (PMB) and radial hybrid magnetic bearing (HMB). For the PMB, a pair of ring-type Halbach arrays of permanent magnets are arranged vertically to support the rotor weight. For the HMB, a set of ring-type Halbach array is placed on the rotor side, which corresponds to coil sets on the stator side. The HMB can produce both attraction and repulsion forces on the radial direction, depending on the direction of the coil currents. It is found that the ring-type configuration and the differential winding scheme for coil sets can yield linear magnetic force models for both PMB and HMB. Based on the obtained magnetic force model, an integral sliding mode controller is designed for the stable rotor levitation in the radial direction. The experimental results show that the rotor can be stabilized to the bearing center, verifying the accuracy of the magnetic force models and effectiveness of the levitation controller.

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Magnetic Fields and Forces in Permanent Magnet Levitated Bearings

Cited by 35 publications

References 7 publications

Integrated Design and Optimization Method of an Asymmetric Hybrid Thrust Magnetic Bearing With Secondary Air-Gap

Integrated Design and Optimization Method of an Asymmetric Hybrid Thrust Magnetic Bearing With Secondary Air-Gap

Modeling for Three-Pole Radial Hybrid Magnetic Bearing Considering Edge Effect

Design, Modeling and Control of Magnetic Bearings for a Ring-Type Flywheel Energy Storage System

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