Novel Magnetically Levitated Two-Level Motor

Several processes in chemical, pharmaceutical, biotechnology, and semiconductor industry require contactless levitation and rotation through a hermetically closed chamber wall. This paper presents a novel concept that combines crucial advantages such as high acceleration capability, large air gap, and a compact motor setup. The basic idea is to separate a homopolar bearing unit axially from a multipolar drive unit on two different height levels. Hence, the proposed concept is denominated as ldquomagnetically levitated two-level motor.rdquo In this paper, the bearing and drive functionalities are explained in detail and design guidelines are given based on analytic equations and electromagnetic 3-D simulations. Furthermore, the influence of nonidealities such as saturation and coupling effects is evaluated and included in the design. Finally, extensive measurements on an experimental prototype exemplify the design considerations and prove the excellent performance of the new concept.

[1]  B. Adkins,et al.  The permanent-magnet synchronous motor , 1962 .

[2]  R. M. Stephan,et al.  A bearingless method for induction machines , 1993 .

[3]  M.A. Rahman,et al.  Vibration Suppression of a Flexible Shaft With a Simplified Bearingless Induction Motor Drive , 2008, IEEE Transactions on Industry Applications.

[4]  M.N. Sahinkaya,et al.  Multiple Sliding and Rolling Contact Dynamics for a Flexible Rotor/Magnetic Bearing System , 2007, IEEE/ASME Transactions on Mechatronics.

[5]  Akira Chiba,et al.  Characteristics of a bearingless induction motor , 1991 .

[6]  Akira Chiba,et al.  Winding Design and Characteristic of a Consequent-Pole Type Bearingless Motor with 4-Axis Active Magnetic Suspension , 2007, 2007 IEEE Industry Applications Annual Meeting.

[7]  N. Watanabe,et al.  Basic Characteristic of the Multi-Consequent-Pole Bearingless Motor , 2007, 2007 Power Conversion Conference - Nagoya.

[8]  W. Amrhein,et al.  Levitation forces in bearingless permanent magnet motors , 1999, IEEE International Magnetics Conference.

[9]  A. Hamler,et al.  Analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation , 2000 .

[10]  S. Earnshaw.  On the Nature of the Molecular Forces which Regulate the Constitution of the Luminiferous Ether , .

[11]  J.W. Kolar,et al.  Saturation effects in high acceleration bearingless motors , 2008, 2008 IEEE International Symposium on Industrial Electronics.

[12]  M.A. Rahman,et al.  Stiffness analysis of a magnetically suspended bearingless motor with permanent magnet passive positioning , 2005, IEEE Transactions on Magnetics.

[13]  Kay Hameyer,et al.  Optimization of radial active magnetic bearings using the finite element technique and the differential evolution algorithm , 2000 .

[14]  Natale Barletta,et al.  Design of a Bearingless Blood Pump , 1996 .

[15]  Jean-Paul Yonnet,et al.  Classification and synthesis of permanent magnet bearing configurations , 1995 .

[16]  Murray Moo-Young,et al.  Clean-in-place systems for industrial bioreactors: Design, validation and operation , 2005, Journal of Industrial Microbiology.

[17]  W. Amrhein,et al.  Design aspects of bearingless slice motors , 2005, IEEE/ASME Transactions on Mechatronics.

[18]  B. Hribernik,et al.  Impact of shape of stator pole of one phase brushless motor on cogging torque , 1996 .

[19]  Natale Barletta,et al.  Principle and Application of a Bearingless Slice Motor , 1997 .

[20]  S. Whitley,et al.  Development of active magnetic bearings for high speed rotors , 1990, International Conference on Magnetics.

[21]  B. J. Chalmers,et al.  Influence of machine symmetry on reduction of cogging torque in permanent-magnet brushless motors , 2000 .

[22]  J.W. Kolar,et al.  Novel Integrated Bearingless Hollow-Shaft Drive , 2006, Conference Record of the 2006 IEEE Industry Applications Conference Forty-First IAS Annual Meeting.

[23]  Zhijun Cai,et al.  Model-Based Control of Active Tilting-Pad Bearings , 2007, IEEE/ASME Transactions on Mechatronics.

[24]  T. Fukao,et al.  Basic characteristics of a permanent-magnet type bearingless motor with positive salient pole , 2007, 2007 International Conference on Electrical Machines and Systems (ICEMS).

[25]  Izzet Yilmaz Önel,et al.  Induction Motor Bearing Failure Detection and Diagnosis: Park and Concordia Transform Approaches Comparative Study , 2007 .

[26]  R. Gerber,et al.  Sensors for magnetic bearings , 1993 .

[27]  J.-P. Yonnet,et al.  Permanent magnet bearings and couplings , 1981 .

[28]  Izzet Yilmaz,et al.  Induction Motor Bearing Failure Detection and Diagnosis: Park and Concordia Transform Approaches Comparative Study , 2008 .