Home Physical Sciences Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure
Article Open Access

Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure

  • Atsushi Nakajima EMAIL logo , Katsuhiro Hirata , Noboru Niguchi and Masayuki Kato
Published/Copyright: March 8, 2018

Abstract

Supporting forces of magnetic bearings are lower than those of mechanical bearings. In order to solve these problems, this paper proposes a new three-axis active control magnetic bearing (3-axis AMB) with an asymmetric structure where its rotor is attracted only in one axial direction due to a negative pressure of fluid. Our proposed 3-axis AMB can generate a large suspension force in one axial direction due to the asymmetric structure. The performances of our proposed 3-axis AMB are computed through 3-D finite element analysis.

1 Introduction

Magnetic bearings realize a high-speed rotation, long life, low noise and dust-free operation because of their contactless and oil-less constitutions [1,2,3,4,5,6]. Because of these advantages, the magnetic bearings are practically used in turbomachinery and high-speed rotating machines. In order to support the rotating shaft using the magnetic bearings, a five-axis control (three translational axes, and two rotating axes except the rotating axis of the shaft) is needed. Generally, the stiffness of the magnetic bearings is lower than that of the mechanical bearings. Therefore the system tends to become large and the critical rotation speed also tends to decrease. In addition, a flat disk generating thrust forces causes a complicated manufacturing process and decreases the rotation speed limit. Recently, 3-axis AMBs have been proposed in order to increase the critical rotation speed and remove the flat disk [7,8,9,10,11]. However, their supporting forces are not high enough.

In this paper, we propose a new 3-axis AMB with an asymmetric structure for a canned motor where its rotor is attracted only in one axial direction due to a negative pressure of fluid. Our proposed 3-axis AMB can generate a large suspension force in one axial direction due to the asymmetric structure. The performances of our proposed 3-axis AMB are computed through 3-D finite element analysis (3-D FEA), and its effectiveness is verified.

2 Structure and operating principle

2.1 Basic structure

The sectional view of the proposed three-axis magnetic bearing is shown in Figure 1. This magnetic bearing consists of a radial stator, three thrust stators and a rotor. The radial stator is axially sandwiched by the thrust stators z1 and z2, and a non-magnetic material is inserted between the thrust stators z2 and z3. The radial stator with 8 electromagnetic poles is formed by laminated silicon steel sheets, and has 8 radial coils. 2 adjacent radial coils are wound in the opposite direction with each other and are connected in series. Therefore, the radial coils consist of 4 circuits: positive and negative coils (x1, x2) for X-axis, and positive and negative coils (y1, y2) for Y-axis as shown in Figure 2 (a). The thrust coils z1 and z2 are connected in series. The rotor consists of a magnetic material and 2 non-magnetic materials (A, and B) are inserted as shown in Figure 1 (b). The non-magnetic material A leads magnetic fluxes from the rotor to the radial stator as shown in Figure 2 (b). The non-magnetic material B controls magnetic fluxes so that the thrust force due to the thrust stator z2 in the positive direction of Z-axis will not be generated.

Figure 1 New three-axis magnetic bearing with asymmetric structure
Figure 1

New three-axis magnetic bearing with asymmetric structure

Figure 2 Operating principle
Figure 2

Operating principle

2.2 Operating principle

The operating principle of our proposed magnetic bearing is shown in Figure 2. A radial suspension force is generated by the magnetic flux due to the radial coils. A magnetic flux due to one set of excited coils flows through the air gap (Figure 2 (a)). This magnetic flux generates a magnetic attractive force between the stator and the rotor. This magnetic attractive force is used as a radial suspension force.

A positive Z-axis thrust force is generated by the magnetic flux due to the thrust coils z1 and z2. When the coil z1 and coil z2 are excited in the same direction, a magnetic flux flows through the thrust stator, rotor, radial stator and air gap (Figure 2 (b)). This magnetic flux flows through the radial stator so as to avoid the non-magnetic parts in the rotor facing the radial stator. Therefore, a magnetic attractive force is generated by the magnetic flux obliquely flowing between the stator and the rotor. Because the radial magnetic attractive force is cancelled in the circumference, only the axial magnetic attractive force remains. This magnetic attractive force is used as a radial suspension force.

Similarly, a negative Z-axis thrust force is generated by the magnetic flux due to the thrust coil z3. A negative Z-axis thrust force utilizes the magnetic attractive force at the low edge of the rotor.

3 Analyzed results

3.1 Computed result by 3-D FEM

We conducted 3-D FEAs to evaluate a supporting force of the proposed 3-axis AMB, where its specification is shown in Table 1. The analysis condition is shown in Table 2.

Table 1

Analysis specifications

Outer diameter130
StatorInner diameter50.2
Height75
Dimension [mm]Outer diameter49.1
RotorInner diameter29.5
Height67.9
Air gap lengthRadial0.55

Table 2

Analysis specifications

CPUIntel(R) Xeon(R) CPU E5-2609 v2
Number of elements1,064,688
 Number ofnodes181,147

Each bearing force was analyzed by changing the rotor’s X- and Z-axis displacements, X-axis radial current and positive Z-axis thrust current. The influence of the X-axis displacement on the X-axis radial suspension force is shown in Figure 3. In this case, the maximum radial suspension force was about 180 N, and when the rotor moves in the positive direction of X-axis, the radial air gap length decreases and the radial suspension force increases. In addition, it is observed that the rate of the increase of the suspension forces decreases as the current density increases. This is because of magnetic saturations in the stator and the rotor (Figure 4).

Figure 3 Radial suspension force v.s. current density of the radial
coil
Figure 3

Radial suspension force v.s. current density of the radial coil

Figure 4 Magnetic flux density when radial coils x1 are excited
Figure 4

Magnetic flux density when radial coils x1 are excited

Table 3. shows the computed suspension forces when each coil is excited independently. The current density of the coils are 12 A/mm2 and the rotor is fixed in an initial position. From Table 3., it is observed that the suspension force in the positive direction of Z-axis is significantly higher than the other forces due to the asymmetric structure.

Table 3

Analysis specifications

Suspension force
Exicitation coil
Direction forceForce [N]
 Radial coil+x179
Thrust coil( +z)+z830
Thrust coil(-z)-z131

3.2 Active control

The controllability of the proposed 3-axis AMB under position control is investigated. A position feedback control system using a PID controller is built to achieve a stable controllability in the X- and Z-axis directions as shown in Figure 5. The suspension forces are determined from the suspension force data table in each axis calculated from 3-D FEA. The maximum allowable displacements of the X- and Z-axis are 0.1 mm and 0.15 mm, respectively, and the maximum current density in the coils is 12 A/mm2.

Figure 5 Position feedback control block diagram
Figure 5

Position feedback control block diagram

In order to verify the controllability of the proposed 3-axis AMB, the displacements in the X- and Z-axis directions were simulated when an external force is applied from 0 to 600 N as shown in Figure 6. In this simulation, the initial positions in the X- and Z-axis directions are 0 and 0.15 mm, respectively.

Figure 6 Simulation result of Z-axis position control
Figure 6

Simulation result of Z-axis position control

The simulated displacement in the X- and Z-axis directions are shown in Figure 6. From Figure 6, the displacement in the X-axis direction is almost 0, and the radial coils are not used. In addition, it is observed that the displacement in the Z-axis direction is converged to 0. In this simulation, the maximum thrust current density was less than 12 A/mm2. From these results, it can be concluded that the proposed 3-axis AMB can generate a sufficient thrust force and is effective for a canned motor.

Next, the position controllability in a steady operation when an instantaneous external force is applied in the X-axis direction is investigated. An external force of 175 N was applied in the negative direction of x-axis. The displacements are shown in Figure 7. A displacement increases in the X-axis due to the external force, however it can be controlled within the allowable displacement. The current density was also within the allowable value. In this time, a displacement also increases in the Z-axis direction, however it can be controlled within the allowable value. This is because the X-axis displacement affected the thrust force due to the magnetic structure.

Figure 7 Controllability when an external force is applied in the X axis
Figure 7

Controllability when an external force is applied in the X axis

Similarly, in a steady state, an external force was applied only in the Z axis. The displacement is shown in Figure 8. In this case the Z-axis displacement can be controlled within the allowable displacement and current density.

Figure 8 Control of Z-axis disturbance
Figure 8

Control of Z-axis disturbance

Finally, external forces were simultaneously applied in the X- and Z-axis. The displacement is shown in Figure 9. The displacement of each axis can be controlled within the allowable displacement and current density.

Figure 9 Controllability when external forces are applied in the X and Z axes
Figure 9

Controllability when external forces are applied in the X and Z axes

From these results, the proposed magnetic bearing can be controlled within the allowable displacement and current density against instantaneous external forces.

4 Conclusion

In this paper, we proposed a new three-axis active control magnetic bearing with an asymmetric structure to increase its thrust force. The operational principle was described and the fundamental suspension force characteristics of the proposed magnetic bearings were evaluated employing 3D-FEM. By arranging non-magnetic material parts in the rotor and controlling the flow of the magnetic flux, it was possible to generate a large thrust force in one direction.

In addition, we verified the controllability of the proposed AMB by conducting a control simulation using a PID control. It was verified that the proposed bearing can control the displacement within the allowable displacement and current density when instantaneous external forces are applied.

In future works, we will perform dynamic analysis coupled with 3-D FEM and simulation. In addition, the computed characteristics will be verified by carrying out measurements on a prototype.

References

[1] Kashitani Y., Shimomura S., Novel Slipring-less Winding-Excited Synchronous Machine, in Proc. 2011 14th International Conference on Electrical Machines and Systems, 2011, 1-6.Search in Google Scholar

[2] Okada Y., Sagawa K., Suzuki E., Kondo R., Development and Application of Parallel PM Type Hybrid Magnetic Bearing, Transactions of the JSME, 2009, 4, 3, 530-53910.1299/jsdd.3.530Search in Google Scholar

[3] Asama J., Chiba A., Fukao T., Design and Performance Evaluation of a Coreless Thrust Magnetic Bearing with a Cylindrical Permanent Magnet Mover, IEEJ Transactions on IA, 2009, 129, 11, 1085-109110.1541/ieejias.129.1085Search in Google Scholar

[4] Noh M.D., Cho S., Kyung J., Design and implementation of a fault-tolerant magnetic bearing systems for turbo-molecular vacuum Pump, IEEE/ASME Transactions on Mechatronics, 2005, 10, 6, 626-63110.1109/TMECH.2005.859830Search in Google Scholar

[5] Schweitzer G., Maslen E.H., Magnetic Bearings -Theory, Design, and Application to Rotating Machinery, Springer, 2009Search in Google Scholar

[6] Chiba A., Fukao T., Ichikawa O., Oshima M., Takemoto M., Dorrell D.G., Magnetic Bearings and Bearingless Drives, Elsevier, 200510.1016/B978-075065727-3/50006-7Search in Google Scholar

[7] Hijikata K., Kobayashi S., Takemoto M., Basic Characteristics of an Active Thrust Magnetic Bearing With a Cylindrical Rotor Core, IEEE Transactions on Magnetics, 2008, 44, 11, 4167-417010.1109/TMAG.2008.2002628Search in Google Scholar

[8] Hijikata K., Takemoto M., Ogasawara S., Behavior of a Novel Thrust Magnetic Bearing With a Cylindrical Rotor on High Speed Rotation, IEEE Transactions on Magnetics, 2009, 45, 10, 4617-462010.1109/TMAG.2009.2022178Search in Google Scholar

[9] Saito T., Masuzawa T., Nakayama N., Development of a novel hybrid type magnetic bearing and application to small impeller centrifugal pumps for artificial hearts, The Society of Life Support Technology, 2006, 18, 4, 19-2410.5136/lifesupport.18.148Search in Google Scholar

[10] McMullen P.T., Huynh C.S., Hayes R.J., Combination Radial-Axial Magnetic Bearing, Seventh International Symp. on Magnetic Bearings (23-25 August 2000, Zurich, Switzerland), ETH Zurich, 2000Search in Google Scholar

[11] Tsuchida K., Takemoto M., Ogasawara S., A Novel Structure of a 3-axis Active Control Type Magnetic Bearing With a Cylindrical Rotor, International Conference on Electrical Machines and Systems (10-13 October 2010, Incheon, Korea), Songdo Convensia, 2010Search in Google Scholar

Received: 2017-11-01
Accepted: 2017-11-12
Published Online: 2018-03-08

© 2018 Atsushi Nakajima et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Articles in the same Issue

  1. Regular Articles
  2. A modified Fermi-Walker derivative for inextensible flows of binormal spherical image
  3. Algebraic aspects of evolution partial differential equation arising in the study of constant elasticity of variance model from financial mathematics
  4. Three-dimensional atom localization via probe absorption in a cascade four-level atomic system
  5. Determination of the energy transitions and half-lives of Rubidium nuclei
  6. Three phase heat and mass transfer model for unsaturated soil freezing process: Part 1 - model development
  7. Three phase heat and mass transfer model for unsaturated soil freezing process: Part 2 - model validation
  8. Mathematical model for thermal and entropy analysis of thermal solar collectors by using Maxwell nanofluids with slip conditions, thermal radiation and variable thermal conductivity
  9. Constructing analytic solutions on the Tricomi equation
  10. Feynman diagrams and rooted maps
  11. New type of chaos synchronization in discrete-time systems: the F-M synchronization
  12. Unsteady flow of fractional Oldroyd-B fluids through rotating annulus
  13. A note on the uniqueness of 2D elastostatic problems formulated by different types of potential functions
  14. On the conservation laws and solutions of a (2+1) dimensional KdV-mKdV equation of mathematical physics
  15. Computational methods and traveling wave solutions for the fourth-order nonlinear Ablowitz-Kaup-Newell-Segur water wave dynamical equation via two methods and its applications
  16. Siewert solutions of transcendental equations, generalized Lambert functions and physical applications
  17. Numerical solution of mixed convection flow of an MHD Jeffery fluid over an exponentially stretching sheet in the presence of thermal radiation and chemical reaction
  18. A new three-dimensional chaotic flow with one stable equilibrium: dynamical properties and complexity analysis
  19. Dynamics of a dry-rebounding drop: observations, simulations, and modeling
  20. Modeling the initial mechanical response and yielding behavior of gelled crude oil
  21. Lie symmetry analysis and conservation laws for the time fractional simplified modified Kawahara equation
  22. Solitary wave solutions of two KdV-type equations
  23. Applying industrial tomography to control and optimization flow systems
  24. Reconstructing time series into a complex network to assess the evolution dynamics of the correlations among energy prices
  25. An optimal solution for software testing case generation based on particle swarm optimization
  26. Optimal system, nonlinear self-adjointness and conservation laws for generalized shallow water wave equation
  27. Alternative methods for solving nonlinear two-point boundary value problems
  28. Global model simulation of OH production in pulsed-DC atmospheric pressure helium-air plasma jets
  29. Experimental investigation on optical vortex tweezers for microbubble trapping
  30. Joint measurements of optical parameters by irradiance scintillation and angle-of-arrival fluctuations
  31. M-polynomials and topological indices of hex-derived networks
  32. Generalized convergence analysis of the fractional order systems
  33. Porous flow characteristics of solution-gas drive in tight oil reservoirs
  34. Complementary wave solutions for the long-short wave resonance model via the extended trial equation method and the generalized Kudryashov method
  35. A Note on Koide’s Doubly Special Parametrization of Quark Masses
  36. On right-angled spherical Artin monoid of type Dn
  37. Gas flow regimes judgement in nanoporous media by digital core analysis
  38. 4 + n-dimensional water and waves on four and eleven-dimensional manifolds
  39. Stabilization and Analytic Approximate Solutions of an Optimal Control Problem
  40. On the equations of electrodynamics in a flat or curved spacetime and a possible interaction energy
  41. New prediction method for transient productivity of fractured five-spot patterns in low permeability reservoirs at high water cut stages
  42. The collinear equilibrium points in the restricted three body problem with triaxial primaries
  43. Detection of the damage threshold of fused silica components and morphologies of repaired damage sites based on the beam deflection method
  44. On the bivariate spectral quasi-linearization method for solving the two-dimensional Bratu problem
  45. Ion acoustic quasi-soliton in an electron-positron-ion plasma with superthermal electrons and positrons
  46. Analysis of projectile motion in view of conformable derivative
  47. Computing multiple ABC index and multiple GA index of some grid graphs
  48. Terahertz pulse imaging: A novel denoising method by combing the ant colony algorithm with the compressive sensing
  49. Characteristics of microscopic pore-throat structure of tight oil reservoirs in Sichuan Basin measured by rate-controlled mercury injection
  50. An activity window model for social interaction structure on Twitter
  51. Transient thermal regime trough the constitutive matrix applied to asynchronous electrical machine using the cell method
  52. On the zagreb polynomials of benzenoid systems
  53. Integrability analysis of the partial differential equation describing the classical bond-pricing model of mathematical finance
  54. The Greek parameters of a continuous arithmetic Asian option pricing model via Laplace Adomian decomposition method
  55. Quantifying the global solar radiation received in Pietermaritzburg, KwaZulu-Natal to motivate the consumption of solar technologies
  56. Sturm-Liouville difference equations having Bessel and hydrogen atom potential type
  57. Study on the response characteristics of oil wells after deep profile control in low permeability fractured reservoirs
  58. Depiction and analysis of a modified theta shaped double negative metamaterial for satellite application
  59. An attempt to geometrize electromagnetism
  60. Structure of traveling wave solutions for some nonlinear models via modified mathematical method
  61. Thermo-convective instability in a rotating ferromagnetic fluid layer with temperature modulation
  62. Construction of new solitary wave solutions of generalized Zakharov-Kuznetsov-Benjamin-Bona-Mahony and simplified modified form of Camassa-Holm equations
  63. Effect of magnetic field and heat source on Upper-convected-maxwell fluid in a porous channel
  64. Physical cues of biomaterials guide stem cell fate of differentiation: The effect of elasticity of cell culture biomaterials
  65. Shooting method analysis in wire coating withdrawing from a bath of Oldroyd 8-constant fluid with temperature dependent viscosity
  66. Rank correlation between centrality metrics in complex networks: an empirical study
  67. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering
  68. Modeling of electric and heat processes in spot resistance welding of cross-wire steel bars
  69. Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure
  70. Design optimization of an axial-field eddy-current magnetic coupling based on magneto-thermal analytical model
  71. Thermal constitutive matrix applied to asynchronous electrical machine using the cell method
  72. Temperature distribution around thin electroconductive layers created on composite textile substrates
  73. Model of the multipolar engine with decreased cogging torque by asymmetrical distribution of the magnets
  74. Analysis of spatial thermal field in a magnetic bearing
  75. Use of the mathematical model of the ignition system to analyze the spark discharge, including the destruction of spark plug electrodes
  76. Assessment of short/long term electric field strength measurements for a pilot district
  77. Simulation study and experimental results for detection and classification of the transient capacitor inrush current using discrete wavelet transform and artificial intelligence
  78. Magnetic transmission gear finite element simulation with iron pole hysteresis
  79. Pulsed excitation terahertz tomography – multiparametric approach
  80. Low and high frequency model of three phase transformer by frequency response analysis measurement
  81. Multivariable polynomial fitting of controlled single-phase nonlinear load of input current total harmonic distortion
  82. Optimal design of a for middle-low-speed maglev trains
  83. Eddy current modeling in linear and nonlinear multifilamentary composite materials
  84. The visual attention saliency map for movie retrospection
  85. AC/DC current ratio in a current superimposition variable flux reluctance machine
  86. Influence of material uncertainties on the RLC parameters of wound inductors modeled using the finite element method
  87. Cogging force reduction in linear tubular flux switching permanent-magnet machines
  88. Modeling hysteresis curves of La(FeCoSi)13 compound near the transition point with the GRUCAD model
  89. Electro-magneto-hydrodynamic lubrication
  90. 3-D Electromagnetic field analysis of wireless power transfer system using K computer
  91. Simplified simulation technique of rotating, induction heated, calender rolls for study of temperature field control
  92. Design, fabrication and testing of electroadhesive interdigital electrodes
  93. A method to reduce partial discharges in motor windings fed by PWM inverter
  94. Reluctance network lumped mechanical & thermal models for the modeling and predesign of concentrated flux synchronous machine
  95. Special Issue Applications of Nonlinear Dynamics
  96. Study on dynamic characteristics of silo-stock-foundation interaction system under seismic load
  97. Microblog topic evolution computing based on LDA algorithm
  98. Modeling the creep damage effect on the creep crack growth behavior of rotor steel
  99. Neighborhood condition for all fractional (g, f, n′, m)-critical deleted graphs
  100. Chinese open information extraction based on DBMCSS in the field of national information resources
  101. 10.1515/phys-2018-0079
  102. CPW-fed circularly-polarized antenna array with high front-to-back ratio and low-profile
  103. Intelligent Monitoring Network Construction based on the utilization of the Internet of things (IoT) in the Metallurgical Coking Process
  104. Temperature detection technology of power equipment based on Fiber Bragg Grating
  105. Research on a rotational speed control strategy of the mandrel in a rotary steering system
  106. Dynamic load balancing algorithm for large data flow in distributed complex networks
  107. Super-structured photonic crystal fiber Bragg grating biosensor image model based on sparse matrix
  108. Fractal-based techniques for physiological time series: An updated approach
  109. Analysis of the Imaging Characteristics of the KB and KBA X-ray Microscopes at Non-coaxial Grazing Incidence
  110. Application of modified culture Kalman filter in bearing fault diagnosis
  111. Exact solutions and conservation laws for the modified equal width-Burgers equation
  112. On topological properties of block shift and hierarchical hypercube networks
  113. Elastic properties and plane acoustic velocity of cubic Sr2CaMoO6 and Sr2CaWO6 from first-principles calculations
  114. A note on the transmission feasibility problem in networks
  115. Ontology learning algorithm using weak functions
  116. Diagnosis of the power frequency vacuum arc shape based on 2D-PIV
  117. Parametric simulation analysis and reliability of escalator truss
  118. A new algorithm for real economy benefit evaluation based on big data analysis
  119. Synergy analysis of agricultural economic cycle fluctuation based on ant colony algorithm
  120. Multi-level encryption algorithm for user-related information across social networks
  121. Multi-target tracking algorithm in intelligent transportation based on wireless sensor network
  122. Fast recognition method of moving video images based on BP neural networks
  123. Compressed sensing image restoration algorithm based on improved SURF operator
  124. Design of load optimal control algorithm for smart grid based on demand response in different scenarios
  125. Face recognition method based on GA-BP neural network algorithm
  126. Optimal path selection algorithm for mobile beacons in sensor network under non-dense distribution
  127. Localization and recognition algorithm for fuzzy anomaly data in big data networks
  128. Urban road traffic flow control under incidental congestion as a function of accident duration
  129. Optimization design of reconfiguration algorithm for high voltage power distribution network based on ant colony algorithm
  130. Feasibility simulation of aseismic structure design for long-span bridges
  131. Construction of renewable energy supply chain model based on LCA
  132. The tribological properties study of carbon fabric/ epoxy composites reinforced by nano-TiO2 and MWNTs
  133. A text-Image feature mapping algorithm based on transfer learning
  134. Fast recognition algorithm for static traffic sign information
  135. Topical Issue: Clean Energy: Materials, Processes and Energy Generation
  136. An investigation of the melting process of RT-35 filled circular thermal energy storage system
  137. Numerical analysis on the dynamic response of a plate-and-frame membrane humidifier for PEMFC vehicles under various operating conditions
  138. Energy converting layers for thin-film flexible photovoltaic structures
  139. Effect of convection heat transfer on thermal energy storage unit
Downloaded on 11.2.2026 from https://www.degruyterbrill.com/document/doi/10.1515/phys-2018-0002/html
Scroll to top button