Magnetic Bearings and Bearingless Drives (eBook)

Akira Chiba, David G Dorrell, Tadashi Fukao, Osamu Ichikawa, Masahide Oshima, Masatugu Takemoto (Autoren)

eBook Download: PDF | EPUB

2005 | 1. Auflage
400 Seiten
Elsevier Science (Verlag)
978-0-08-047897-5 (ISBN)

Infos

The application of bearingless drives is emerging as an important technique in the areas of high-speed machinery and motion-control, and this book aims to provide a thorough grounding in the principles behind this cutting-edge technology. Basic principles are described in detail with practical examples to aid understanding, and the different types of bearingless drives are introduced, along with coverage of test machines and applications.

Aimed at practising electrical and mechanical engineers and advanced students, Magnetic Bearings and Bearingless Drives provides an essential guide to an area of engineering previously only fully covered by large numbers of academic papers.

? Unique and comprehensive coverage of a cutting-edge subject for electrical and mechanical engineers
? A reference text and survey for designers, manufacturers and users of high-speed motors, generators and electrical drive systems
? Examines the basic principles behind magnetic bearings, with key technologies and applications illustrated through examples and case studies

Inhalt

Cover 1
Frontmatter 2
Half Title Page 2
Title Page 4
Copyright 5
Contents 6
List of Contributors 10
Foreword 11
Preface 13
Acknowledgements 17
1. Introduction 20
1.1 Magnetic bearing and motor drive 20
1.2 Bearingless drives 23
1.3 Definition and related technologies 24
1.4 Early developments 26
1.5 Bearingless structures 28
1.6 Comparisons 30
1.7 Winding structures 32
1.8 Applications 33
References 34
2. Electro-magnetics and mathematical model of magnetic bearings 35
2.1 Electro-mechanical structure and operating principles 35
2.2 Electric equivalent circuit and inductance 36
2.3 Stored magnetic energy and force 39
2.4 Radial magnetic bearing 53
2.5 Unbalance pull force 59
2.6 Block diagram and mechanical system 61
Reference 63
3. Magnetic bearing controllers 64
3.1 Design principles in one-axis magnetic suspension 64
3.2 Adjustment of PID gains 71
3.3 Interference in two perpendicular axes 86
3.4 Unbalance force and elimination 91
3.5 Eccentric displacement 97
3.6 Synchronized displacement suppression 100
4. Mechanical dynamics 104
4.1 Two-axis system 104
4.2 Four-axis and five-axis systems 109
4.3 Thrust magnetic bearing and requirement of five-axis suspension 113
References 115
5. Power electronic circuits for magnetic bearings 116
5.1 Structure and principles of power electronic circuits 116
5.2 PWM operation 126
5.3 Current feedback 131
5.4 Current driver operating area 138
5.5 Power devices and gate drive circuits 141
6. Primitive model and control strategy of bearingless motors 146
6.1 Principles of radial force generation 146
6.2 Two-pole bearingless motor 150
6.3 MMF and permeance 151
6.4 Magnetic potential and flux distribution 154
6.5 Inductance matrix 157
6.6 Radial force and current 160
6.7 The dc excitation of the primitive bearingless motor 164
6.8 AC excitation and revolving magnetic field 166
6.9 Inductance measurements 168
7. Analysis in rotational coordinates and magnetic suspension strategy for bearingless drives with 2-pole and 4-pole windings 178
7.1 Vector control theory of electrical motors 179
7.2 Coordinate transformation and torque regulation 185
7.3 Vector control theory in bearingless motors 188
7.4 Coordinate transformation from dc to ac bearingless machines 192
7.5 System block diagrams of bearingless machines 196
References 202
8. Field orientation, VA requirement and magnetic saturation 203
8.1 Misalignment of field orientation 204
8.2 VA requirement 209
8.3 Magnetic saturation 216
References 219
9. Cylindrical permanent magnet synchronous bearingless motors 220
9.1 Structure of surface permanent magnet (SPM) rotor 220
9.2 Radial suspension force and suspension winding current 221
9.3 Equations of voltage and current 223
9.4 Guideline for permanent magnet thickness and airgap length 224
9.5 Irreversible permanent magnet demagnetization and MMF limitations of stator windings 231
9.6 Control system configuration 235
References 238
10. Inset types of permanent magnet bearingless motor 239
10.1 Structure and features of an inset type of permanent magnet rotor 239
10.2 Mutual interference between radial suspension forces 240
10.3 Rotor position control strategy 242
10.4 Identification of suspension force parameters 242
References 247
11. Buried permanent magnet bearingless motors 248
11.1 BPM rotor structures 248
11.2 Suspension force for unity current and permanent magnet demagnetization 250
11.3 Rotor position control strategy 251
References 256
12. Synchronous reluctance bearingless motors 257
12.1 Torque characteristics 257
12.2 Radial force characteristics 260
12.3 Drive systems 263
References 269
13. Bearingless induction motors 270
13.1 Rotor structure and suspension force 270
13.2 Indirect type drives 276
13.3 Direct type drives 283
13.4 Two-pole motor drive 290
References 291
14. Homopolar, hybrid and consequent-pole bearingless motors 293
14.1 Structures and principles 293
14.2 Number of poles 300
14.3 Drive systems 303
References 305
15. Switched reluctance bearingless motors 306
15.1 Configuration of stator windings and principles of suspension force generation 307
15.2 Derivation of inductances 309
15.3 Assumption and calculation of permeances 310
15.4 Theoretical formulae of suspension force and torque 314
15.5 A drive system 316
15.6 A feed-forward compensator for vibration reduction considering magnetic attraction force 321
References 326
16. Winding arrangement variations 328
16.1 Modified radial magnetic bearings [1,2] 328
16.2 Modified motors [3–5] 330
16.3 p-Pole and (p ± 2)-pole windings [9–11] 332
References 335
17. Mechanical structure and position regulation 337
17.1 Mechanical structure 337
17.2 Axial gap bearingless motors 340
References 347
18. Displacement sensors and sensorless operation 348
18.1 Principles of displacement sensor 349
18.2 Improvements in sensitivity 352
18.3 Inductive and eddy current sensors 355
18.4 Sensorless bearingless motor 357
References 361
19. Controllers and power electronics 363
19.1 Structure of digital controllers 363
19.2 Discrete-time systems of PID controllers with the z-transform 366
20. Design procedure and examples 370
20.1 An induction type bearingless motor [1–4] 370
20.2 A permanent magnet type bearingless motor [5,6] 375
References 379
21. Applications and test machines 380
21.1 Canned pumps and drives [1–4] 380
21.2 Compact pumps, bubble bed reactor 384
21.3 Spindle motor and semiconductor processing 389
References 393
Index 394

Produkt-Details

• Erscheint lt. Verlag: 20.5.2005
• Sprache: englisch
• Themenwelt: Sachbuch/Ratgeber
• Themenwelt: Technik ► Bauwesen
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Maschinenbau
• ISBN-10: 0-08-047897-2 / 0080478972
• ISBN-13: 978-0-08-047897-5 / 9780080478975