Levitation and Torque Control of PM Synchronous and Induction Type Bearingless Motor

Abstract General solution of levitation control applicable to PM synchronous and induction type rotating motor is presented. It is intended for a single rotor to have both functions of magnetic bearing and rotating motor. The rotational control is achieved with the traditional P pole magnetic flux, while the radial force is controlled with either P+2 or P−2 pole magnetic flux in the stator. In the previous work, the proposed general theory of levitated motor is successfully confirmed with no load experiments. In this paper, the load capability of the levitated motor is tested using a horizontal type experimental setup. The stator has 8 concentrated wound electromagnets, each of which is controlled individually by a DSP and power amplifier. The radial load is the gravity of the rotor, while the produced rotating torque is measured with a noncontact variable torque load system. The results obtained are discussed in detail.

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Electromagnetic-Induction Type Vehicle Sensor Detecting the Gradient of Magnetic Flux

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss1987.109.12_849 ◽

1989 ◽

Vol 109 (12) ◽

pp. 849-854

Author(s):

Takuya Fujimoto ◽

Kenji Kanavama ◽

Masao Mizuno

Keyword(s):

Magnetic Flux ◽

Electromagnetic Induction ◽

Induction Type ◽

Vehicle Sensor

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A New Control Method for Vibration and Noise Suppression in Switched Reluctance Machines

Energies ◽

10.3390/en12081554 ◽

2019 ◽

Vol 12 (8) ◽

pp. 1554 ◽

Cited By ~ 3

Author(s):

Man Zhang ◽

Imen Bahri ◽

Xavier Mininger ◽

Cristina Vlad ◽

Hongqin Xie ◽

...

Keyword(s):

Control Strategy ◽

Noise Suppression ◽

Control Method ◽

Negative Impact ◽

Low Cost ◽

Radial Force ◽

Torque Control ◽

Transient Condition ◽

Switched Reluctance ◽

Switched Reluctance Machines

Due to their inherent advantages such as low cost, robustness and wide speed range, switched reluctance machines (SRMs) have attracted great attention in electrical vehicles. However, the vibration and noise problems of SRMs limit their application in the automotive industry because of the negative impact on driver and passengers’ comfort. In this paper, a new control method is proposed to improve the vibratory and acoustic behavior of SRMs. Two additional control blocks —direct force control (DFC) and reference current adapter (RCA)—are introduced to the conventional control method (average torque control (ATC)) of SRM. DFC is adopted to control the radial force in the teeth of the stator, since the dynamic of the radial force has a large impact on the vibratory performance. RCA is proposed to handle the trade-off between the DFC and ATC. It produces an auto-tuning current reference to update the reference current automatically depending on the control requirement. The effectiveness of the proposed control strategy is verified by experimental results under both steady and transient condition. The results show that the proposed method improves the acoustic performance of the SRM and maintains the dynamic response of it, which proves the potential of the proposed control strategy.

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Magnetic Bearing Technology for Industrial Bearingless Motor Systems

2019 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD) ◽

10.1109/wemdcd.2019.8887803 ◽

2019 ◽

Cited By ~ 3

Author(s):

Nicholas R. Hemenway ◽

Henrik Gjemdal ◽

Eric L. Severson

Keyword(s):

Magnetic Bearing ◽

Motor Systems ◽

Bearingless Motor

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Development of one-axis controlled bearingless motor and its application to a centrifugal pump for extremely low temperature

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209447 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 1287-1294

Author(s):

Hirohisa Kato ◽

Mochimitsu Komori ◽

Ken-ichi Asami ◽

Nobuo Sakai

Keyword(s):

Low Temperature ◽

Centrifugal Pump ◽

Liquid Nitrogen ◽

Flow Rate ◽

Maximum Flow ◽

Magnetic Bearing ◽

Lubricating Oil ◽

Bearingless Motor ◽

The Difference ◽

Conventional Study

In this paper, a centrifugal pump for for extremely low temperature was fabricated and evaluated by experiments in liquid nitrogen. The pump is using a bearingless motor and permanent magnet bearings to levitate and rotate the rotor without lubricating oil. The difference from the conventional study is that a one-axis controlled bearingless motor is used to reduce the magnetic bearing cost and that the bearings are installed in the liquid to eliminate a shaft-seal. Stable levitation and rotation of the rotor were confirmed in the rotation and pump experiments in liquid nitrogen. In pump experiment, the flow rate of liquid nitrogen was measured at 1 cm in a pumping height. The maximum flow rate was 1.3 L/min when the rotation speed is 1,800 rpm.

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Comparison of three-pole AMB and HMB for magnetic suspended molecular pump

Modern Physics Letters B ◽

10.1142/s0217984918400742 ◽

2018 ◽

Vol 32 (34n36) ◽

pp. 1840074

Author(s):

Jintao Ju ◽

Xiaobin Liu ◽

Zegang Xu ◽

Chao Gu ◽

Yilin Liu

Keyword(s):

Power Loss ◽

High Vacuum ◽

Three Dimensional ◽

Radial Force ◽

Magnetic Bearing ◽

Magnetic Bearings ◽

Active Magnetic Bearing ◽

Rotating Speed ◽

Characteristics Analysis ◽

Current Characteristics

Molecular pumps have been widely used in the vacuum metallurgy, coating, semiconductor manufacturing and many other fields in which the high vacuum, ultra-clean environment is needed. The application of magnetic bearings can bring many advantages for molecular pump, such as eliminating the friction, decreasing the power loss, lowering the maintenance costs, and increasing the rotating speed and service life. Besides, the magnetic bearings can fundamentally solve the vacuum chamber pollution problem which is caused by the backflow of lubrication oil steam. The three-pole magnetic bearings are the simplest structure of radial magnetic bearings and can be driven by three-phase converter which has the advantages of low costs, small volume and low power loss. In this paper, the performance of the three-pole active magnetic bearing (AMB) and hybrid magnetic bearing (HMB) are compared based on radial force–current characteristics analysis. Firstly, the mathematical model of three-pole AMB and HMB is built by equivalent magnetic circuit model, and the radial force–current characteristics are analyzed. Then, simulation by the three-dimensional (3D) finite element method (FEM) is performed. Finally, the experiment is conducted. The FEM results are consistent with the analytical results, showing that the nonlinearity and coupling of three-pole HMB are lower than three-pole AMB. The reason of causing nonlinearity and coupling is also discussed.

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Influence of Rotor Skew in Induction Type Bearingless Motor

IEEE Transactions on Magnetics ◽

10.1109/tmag.2012.2198872 ◽

2012 ◽

Vol 48 (11) ◽

pp. 4646-4649 ◽

Cited By ~ 24

Author(s):

Akira Chiba ◽

Junichi Asama

Keyword(s):

Bearingless Motor ◽

Induction Type

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Hybrid (hydrodynamic + permanent magnetic) journal bearings

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1243/13506501jet282 ◽

2007 ◽

Vol 221 (8) ◽

pp. 881-891 ◽

Cited By ~ 15

Author(s):

H Hirani ◽

P Samanta

Keyword(s):

Permanent Magnets ◽

Load Capacity ◽

Rapid Development ◽

Experimental Studies ◽

Radial Force ◽

Magnetic Bearing ◽

Magnetic Bearings ◽

Axial Thrust ◽

Hydrodynamic Bearing ◽

Load Carrying

Survey of patents on bearings indicates the maturity of hydrodynamic and rapid development of magnetic bearings. Active magnetic bearings are costlier compared with permanent magnetic bearings. To understand the performance characteristics of permanent magnetic bearings, an experimental setup has been developed. Experimental studies on radial permanent magnetic bearings demonstrated the drawbacks, such as high axial thrust and low load capacity. This has led the authors to hybridize the permanent magnet with hydrodynamic technology and to explore the possibility of achieving the low starting torque of a permanent magnetic bearing and the medium to high load carrying capacity of a hydrodynamic bearing in a single bearing arrangement. Simulation is carried out in order to reduce axial force-effect and enhance the radial force supported by the permanent magnetic bearing. Results of simulation on permanent magnetic bearing have been compared with that of published research papers. Finally an algorithm has been developed to investigate the coupling of forces generated by permanent magnets and hydrodynamic actions. Results of load sharing have been reported. The experimentally measured displacements of the shaft running at 500, 2000, and 3000 r/min have been plotted. The effect of hydrodynamics on shaft orbit has been illustrated.

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