Second Edition - VARIABLE SPEED GENERATORS
IEEE Life Fellow
University Politehnica Timisoara
Timisoara, Romania
MATLAB® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not warrant the accuracy of the text or exercises in this book. This book’s use or discussion of MATLAB® software or related products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular use of the MATLAB® software.
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2016 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Version Date: 20150817
International Standard Book Number-13: 978-1-4987-2358-9 (eBook - PDF)
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the valid-ity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or uti-lized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopy-ing, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923,
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Preface to the Second Edition ............................................................................... xiii
Preface to the First Edition ..................................................................................... xv
Author..................................................................................................................... xix
1 Wound-Rotor Induction Generators: Steady State
1.1 Introduction .......................................................................................................................................1
1.2 Construction Elements.................................................................................................................... 3
1.2.1 Magnetic Cores
1.2.2 Windings and Their Magnetomotive Forces................................................................. 5
1.2.3 Slip-Rings and Brushes..................................................................................................... 8
1.3 Steady-State Equations..................................................................................................................... 9
1.4 Equivalent Circuit............................................................................................................................ 11
1.5 Phasor Diagrams .............................................................................................................................13
1.6 Operation at the Power Grid..........................................................................................................18
1.6.1 Stator Power versus Power Angle...................................................................................19
1.6.2 Rotor Power versus Power Angle ...................................................................................21
1.6.3 Operation at Zero Slip (S = 0).........................................................................................21
1.7 Autonomous Operation of WRIGs.............................................................................................. 22
1.8 Operation of WRIGs in the Brushless Exciter Mode................................................................ 26
1.9 Losses and Efficiency of WRIGs....................................................................................................31
1.10 Summary.......................................................................................................................................... 32
References .........34
2 Wound-Rotor Induction Generators: Transients and Control
2.1 Introduction .................................................................................................................................... 37
2.2 WRIG Phase Coordinate Model .................................................................................................. 37
2.3 Space-Phasor Model of WRIG......................................................................................................40
2.4 Space-Phasor Equivalent Circuits and Diagrams...................................................................... 42
2.5 Approaches to WRIG Transients.................................................................................................46
2.6 Static Power Converters for WRIGs............................................................................................ 47
2.6.1 Direct AC–AC Converters............................................................................................. 50
2.6.2 DC Voltage Link AC–AC Converters........................................................................... 52
2.7 Vector Control of WRIG at Power Grid...................................................................................... 54
2.7.1 Principles of Vector Control of Machine (Rotor)-Side Converter........................... 54
2.7.2 Vector Control of Source-Side Converter.................................................................... 57
2.7.3 Wind Power WRIG Vector Control at the Power Grid............................................. 59
2.7.3.1 Wind Turbine Model .................................................................................... 59
2.7.3.2 Supply-Side Converter Model.......................................................................61
2.7.3.3 Generator-Side Converter Model................................................................ 62
2.7.3.4 Simulation Results......................................................................................... 63
2.7.3.5 Three-Phase Short Circuit on the Power Grid.......................................... 65
2.7.3.6 Mechanism to Improve Performance during Fault ................................. 67
2.8 Direct Power Control of WRIG at Power Grid .......................................................................... 68
2.8.1 Concept of DPC
2.9 Independent Vector Control of Positive and Negative Sequence Currents........................... 74
2.10 Motion-Sensorless Control ........................................................................................................... 76
2.11 Vector Control in Stand-Alone Operation ................................................................................. 79
2.12 Self-Starting, Synchronization, and Loading at the Power Grid ............................................ 80
2.13 Voltage and Current Low-Frequency Harmonics of WRIG.................................................... 83
2.14 Ride-Through Control of DFIG under Unbalanced Voltage Sags .......................................... 86
2.15 Stand-Alone DFIG Control under Unbalanced Nonlinear Loads.......................................... 89
2.16 Summary...........................................................................................................................................91
3 Wound-Rotor Induction Generators: Design and Testing
3.1 Introduction .................................................................................................................................... 95
3.2 Design Specifications: An Example .............................................................................................96
3.3 Stator Design ...................................................................................................................................96
3.4 Rotor Design...................................................................................................................................103
3.5 Magnetization Current.................................................................................................................106
3.6 Reactances and Resistances .........................................................................................................109
3.7 Electrical Losses and Efficiency................................................................................................... 113
3.8 Testing of WRIGs.......................................................................................................................... 115
3.9 Summary.........................................................................................................................................116
4 Self-Excited Induction Generators
4.1 Introduction ................................................................................................................................... 119
4.2 Principle of Cage-Rotor Induction Machine............................................................................. 119
4.3 Self-Excitation: A Qualitative View............................................................................................122
4.4 Steady-State Performance of Three-Phase SEIGs.....................................................................123
4.4.1 Second-Order Slip Equation Methods........................................................................124
4.4.2 SEIGs with Series Capacitance Compensation..........................................................128
4.5 Performance Sensitivity Analysis ...............................................................................................128
4.5.1 For Constant Speed........................................................................................................129
4.5.2 For Unregulated Prime Movers ...................................................................................130
4.6 Pole Changing SEIGs for Variable Speed Operation ............................................................... 131
4.7 Unbalanced Operation of Three-Phase SEIGs..........................................................................133
4.8 One Phase Open at Power Grid...................................................................................................136
4.9 Three-Phase SEIG with Single-Phase Output ...........................................................................138
4.10 Two-Phase SEIGs with Single-Phase Output ............................................................................142
4.11 Three-Phase SEIG Transients ......................................................................................................145
4.12 Parallel Connection of SEIGs......................................................................................................148
4.13 Direct Connection to Grid Transients in Cage-Rotor Induction Generators......................150
4.14 More on Power Grid Disturbance Transients in Cage-Rotor Induction
Generators
4.15 Summary.........................................................................................................................................160
5 Stator-Converter-Controlled Induction Generators
5.1 Introduction ...................................................................................................................................165
5.2 Grid-Connected SCIGs: The Control System............................................................................166
5.2.1 Machine-Side PWM Converter Control.....................................................................166
5.2.1.1 State Observers for DTFC of SCIGs ..........................................................167
5.2.1.2 DTFC–SVM Block .......................................................................................173
5.2.2 Grid-Side Converter Control........................................................................................176
5.3 Grid Connection and Four-Quadrant Operation of SCIGs ...................................................176
5.4 Stand-Alone Operation of SCIG..................................................................................................179
5.5 Parallel Operation of SCIGs.........................................................................................................180
5.6 Static Capacitor Exciter Stand-Alone IG for Pumping Systems............................................. 181
5.7 Operation of SCIGs with DC Voltage-Controlled Output......................................................184
5.8 Stand-Alone SCIG with AC Output and Low Rating PWM Converter ...............................187
5.9 Dual Stator Winding for Grid Applications..............................................................................187
5.10 Twin Stator Winding SCIG with 50% Rating Inverter and Diode Rectifier........................189
5.11 Dual Stator Winding IG with Nested Cage Rotor....................................................................190
5.12 Summary.........................................................................................................................................190
6 Automotive Claw-Pole-Rotor Generator Systems
6.1 Introduction ...................................................................................................................................195
6.2 Construction and Principle..........................................................................................................195
6.3 Magnetic Equivalent Circuit Modeling ....................................................................................200
6.4 Three-Dimensional Finite Element Method Modeling .......................................................... 203
6.5 Losses, Efficiency, and Power Factor ......................................................................................... 208
6.6 Design Improvement Steps ..........................................................................................................210
6.6.1 Claw-Pole Geometry ......................................................................................................210
6.6.2 Booster Diode Effects..................................................................................................... 211
6.6.3 Assisting Permanent Magnets......................................................................................212
6.6.4 Increasing the Number of Poles...................................................................................213
6.6.5 Winding Tapping (Reconfiguration)...........................................................................213
6.6.6 Claw-Pole Damper .........................................................................................................216
6.6.7 Controlled Rectifier........................................................................................................216
6.7 Lundell Starter/Generator for Hybrid Vehicles.........................................................................217
6.8 IPM Claw-Pole Alternator System for More Vehicle Braking Energy Recuperation:
A Case Study
6.8.1 3D Nonlinear Magnetic Circuit Model...................................................................... 225
6.8.1.1 Evaluation Design Calibration.................................................................. 226
6.8.2 Optimal Design: Method, Code, and Sample Results with Prototype
Test Results
6.8.3 3D-FEM Analysis.......................................................................................................... 229
6.8.4 Vehicle Braking Energy Recuperation Scheme and Its Control ............................ 232
6.8.4.1 Dynamic Model of the Proposed System ................................................ 233
6.8.4.2 42 VDC Storage Battery Model.................................................................... 236
6.8.4.3 Control Strategy........................................................................................... 237
6.8.4.4 Simulation Results....................................................................................... 238
6.8.5 Extension of IPM Alternator Utilization up to 100 kW Systems............................241
6.9 Summary.........................................................................................................................................241
References
7 Induction Starter/Alternators for Electric Hybrid Vehicles
7.1 Electric Hybrid Vehicle Configuration ..................................................................................... 245
7.2 Essential Specifications................................................................................................................ 248
7.2.1 Peak Torque (Motoring) and Power (Generating)................................................... 248
7.2.2 Battery Parameters and Characteristics.................................................................... 250
7.3 Topology Aspects of Induction Starter/Alternator.................................................................. 253
7.4 ISA Space-Phasor Model and Characteristics.......................................................................... 255
7.5 Vector Control of ISA................................................................................................................... 263
7.6 DTFC of ISA..................................................................................................................................264
7.7 ISA Design Issues for Variable Speed........................................................................................266
7.7.1 Power and Voltage Derating ........................................................................................266
7.7.2 Increasing Efficiency..................................................................................................... 267
7.7.3 Increasing the Breakdown Torque..............................................................................268
7.7.4 Additional Measures for Wide Constant Power Range...........................................269
7.7.4.1 Winding Reconfiguration.......................................................................... 270
7.8 Summary........................................................................................................................................ 273
8 Permanent-Magnet-Assisted Reluctance Synchronous Starter/
Alternators for Electric Hybrid Vehicles
8.1 Introduction .................................................................................................................................. 279
8.2 Topologies of PM-RSM................................................................................................................280
8.3 Finite Element Analysis............................................................................................................... 283
8.3.1 Flux Distribution........................................................................................................... 283
8.3.2 dq Inductances
8.3.3 Cogging Torque
8.3.4 Core Losses Computation by FEM............................................................................. 289
8.4 dq Model of PM-RSM ...................................................................................................................291
8.5 Steady-State Operation at No Load and Symmetric Short Circuit....................................... 297
8.5.1 Generator No-Load....................................................................................................... 297
8.5.2 Symmetrical Short Circuit........................................................................................... 297
8.6 Design Aspects for Wide Speed Range Constant Power Operation.....................................299
8.7 Power Electronics for PM-RSM for Automotive Applications.............................................. 305
8.8 Control of PM-RSM for EHV ..................................................................................................... 307
8.9 State Observers without Signal Injection for Motion Sensorless Control ............................310
8.10 Signal Injection Rotor Position Observers.................................................................................312
8.11 Initial and Low-Speed Rotor Position Tracking .......................................................................313
8.12 50/100 kW, 1350–7000 rpm (600 Nm Peak Torque, 40 kg) PM-Assisted Reluctance
Synchronous Motor/Generator for HEV: A Case Study
8.12.1 Introduction
8.12.2 General Design Summary and Results.......................................................................318
8.12.2.1 Stator Core Geometry..................................................................................318
8.12.2.2 Number of Turns per Coil nc ......................................................................319
8.12.2.3 The Stator Leakage Inductance Ls1
and Ldm/Lqm Requirements.............319
8.12.2.4 Rotor Lamination Design........................................................................... 320
8.12.2.5 Peak Torque Production............................................................................. 320
8.12.2.6 Slot Area/Peak Current Density/Stator Resistance Rs ............................321
8.12.2.7 Weights of Active Materials........................................................................321
8.12.2.8 Performance at 100 kW and 7000 rpm..................................................... 322
8.12.2.9 Performance at 50 kW, 7000 rpm, and 1350 rpm.................................... 323
8.12.2.10 Equivalent Circuit ....................................................................................... 323
8.12.3 Optimal Design Methodology and Results............................................................... 324
8.12.3.1 IPMSM—Analytical Model ....................................................................... 324
8.12.3.2 Optimal Design of IPMSM........................................................................ 324
8.12.4 FEM Validation without and with Rotor Segmentation ......................................... 327
8.12.5 Dynamic Model and Vector Control Performance Validation.............................. 330
8.13 Summary.........................................................................................................................................333
9 Switched Reluctance Generators and Their Control
9.1 Introduction .................................................................................................................................. 339
9.2 Practical Topologies and Principles of Operation................................................................... 339
9.2.1 kW/Peak kVA Ratio.......................................................................................................344
9.3 SRG(M) Modeling ........................................................................................................................346
9.4 Flux/Current/Position Curves....................................................................................................348
9.5 Design Issues................................................................................................................................. 349
9.5.1 Motor and Generator Specifications .......................................................................... 350
9.5.2 Number of Phases, Stator and Rotor Poles: m, Ns, Nr ...............................................351
9.5.3 Stator Bore Diameter Dis and Stack Length ...............................................................351
9.5.4 Number of Turns per Coil Wc for Motoring.............................................................. 353
9.5.5 Current Waveforms for Generator Mode .................................................................. 353
9.6 PWM Converters for SRGs ......................................................................................................... 356
9.7 Control of SRG(M)s...................................................................................................................... 358
9.7.1 Feed-Forward Torque Control of SRG(M) with Position Feedback...................... 359
9.8 Direct Torque Control of SRG(M) .............................................................................................364
9.9 Rotor Position and Speed Observers for Motion-Sensorless Control ..................................366
9.9.1 Signal Injection for Standstill Position Estimation..................................................366
9.10 Output Voltage Control in SRG.................................................................................................. 369
9.11 Double Stator SRG with Segmented Rotor............................................................................... 370
9.12 Summary.........................................................................................................................................371
10 Permanent Magnet Synchronous Generator Systems
10.1 Introduction .................................................................................................................................. 377
10.2 Practical Configurations and Their Characterization............................................................ 378
10.2.1 Distributed versus Concentrated Windings ............................................................. 383
10.3 Air Gap Field Distribution, emf, and Torque........................................................................... 386
10.4 Stator Core Loss Modeling.......................................................................................................... 394
10.4.1 FEM-Derived Core Loss Formulas............................................................................. 394
10.4.2 Simplified Analytical Core Loss Formulas................................................................ 398
10.5 Circuit Model .................................................................................................................................401
10.5.1 Phase Coordinate Model...............................................................................................401
10.5.2 dq Model of PMSG ........................................................................................................402
10.6 Circuit Model of PMSG with Shunt Capacitors and AC Load ..............................................408
10.7 Circuit Model of PMSG with Diode Rectifier Load.................................................................410
10.8 Utilization of Third Harmonic for PMSG with Diode Rectifiers........................................... 411
10.9 Autonomous PMSGs with Controlled Constant Speed and AC Load..................................415
10.10 Grid-Connected Variable-Speed PMSG System.......................................................................418
10.10.1 Diode Rectifier and Boost DC–DC Converter Case................................................420
10.11 PM Genset with Multiple Outputs.............................................................................................422
10.12 Super-High-Speed PM Generators: Design Issues..................................................................426
10.12.1 Rotor Sizing
10.13 Super-High-Speed PM Generators: Power Electronics Control Issues................................ 432
10.14 Design of a 42 VDC Battery-Controlled-Output PMSG System.............................................434
10.14.1 Design Initial Data ........................................................................................................ 435
10.14.2 Minimum Speed: nmin ................................................................................................... 435
10.14.3 Number of Poles: 2p1 ..................................................................................................... 437
10.14.4 Rotor Configuration...................................................................................................... 437
10.14.5 Stator Winding Type..................................................................................................... 438
10.14.6 Winding Tapping .......................................................................................................... 439
10.14.7 PMSG Current Waveform............................................................................................440
10.14.8 Diode Rectifier Imposes Almost Unity Power Factor.............................................440
10.14.9 Peak Torque-Based Sizing............................................................................................440
10.14.10 Generator-to-DC Voltage Relationships....................................................................440
10.14.11 ΨPM, Ls, and Rs
10.15 Methods for Testing PMSGs.......................................................................................................443
10.15.1 Standstill Tests
10.15.2 No-Load Generator Tests.............................................................................................447
10.15.3 Short-Circuit Generator Tests.....................................................................................448
10.15.4 Stator Leakage Inductance and Skin Effect...............................................................448
10.15.5 Motor No-Load Test......................................................................................................450
10.15.6 Generator Load Tests....................................................................................................450
10.16 Grid to Stand-Alone Transition Motion-Sensorless Dual-Inverter Control
of PMSG with Asymmetrical Grid Voltage Sags and Harmonics Filtering:
A Case Study
10.16.1 Voltage Sags Ride-Through Capability ......................................................................454
10.16.1.1 Line Voltage Positive Sequence with D-Module Filter..........................456
10.16.1.2 Line Voltage Angle Estimation ................................................................. 457
10.16.2 Stand-Alone PMSG Control: Harmonic and Negative-Sequence Voltage
Compensation under Nonlinear Load
10.16.3 Seamless Switching Transfer from Stand-Alone to Grid (and Back).................... 458
10.16.3.1 Transition from Stand-Alone to Grid-Connected Mode...................... 459
10.16.3.2 Transition from Grid-Connected to Stand-Alone Mode......................460
10.16.4 PMSG Motion-Sensorless Control System................................................................460
10.16.4.1 PMSG Modeling ..........................................................................................460
10.16.4.2 Active Power and Current Control............................................................461
10.16.4.3 Rotor Position and Speed Observer..........................................................463
10.16.5 Test Platform and Experimental Results...................................................................464
10.16.5.1 Voltage Sags Ride-Through........................................................................464
10.16.5.2 Harmonic and Negative-Sequence Voltage Compensation
under Nonlinear Load
10.16.5.3 Transition from Stand-Alone to Grid-Connected Mode......................467
10.16.5.4 Transition from Grid-Connected to Stand-Alone Mode......................469
10.16.6 Conclusion
10.17 Note on Medium-Power Vehicular Electric Generator Systems............................................471
10.18 Summary........................................................................................................................................ 472
11 Transverse Flux and Flux Reversal Permanent Magnet Generator Systems
11.1 Introduction ..................................................................................................................................479
11.2 Three-Phase Transverse Flux Machine: Magnetic Circuit Design .......................................485
11.2.1 Phase Inductance Ls ......................................................................................................489
11.2.2 Phase Resistance and Slot Area ...................................................................................490
11.3 TFM: The dq Model and Steady State........................................................................................ 493
11.4 Three-Phase FR-PM Generator: Magnetic and Electric Circuit Design
11.4.1 Preliminary Geometry for 200 Nm at 128 rpm via Conceptual Design...............499
11.4.2 FEM Analysis of Pole-PM FRM at No Load .............................................................500
11.4.3 FEM Analysis at Steady State on Load....................................................................... 502
11.4.4 FEM Computation of Inductances............................................................................. 508
11.4.5 Inductances and the Circuit Model of FRM ............................................................. 508
11.4.6 dq Model of FRM............................................................................................................510
11.4.7 Notes on Flux Reversal Generator Control................................................................517
11.5 High Power Factor Vernier PM Generators ..............................................................................521
11.5.1 Power Factor of VPM Machine ....................................................................................521
11.5.1.1 Power Factor..................................................................................................521
11.5.2 DSSA: VPM for Higher Power Factor........................................................................ 523
11.6 Summary........................................................................................................................................ 525
\12 Linear Motion Alternators
12.1 Introduction .................................................................................................................................. 529
12.2 LMA Principle of Operation....................................................................................................... 529
12.2.1 Motion Equation............................................................................................................ 532
12.3 PM-LMA with Coil Mover...........................................................................................................533
12.4 Multipole LMA with Coil Plus Iron Mover.............................................................................. 535
12.5 PM-Mover LMAs...........................................................................................................................541
12.6 Tubular Homopolar PM Mover Single-Coil LMA..................................................................544
12.7 Flux Reversal LMA with Mover PM Flux Concentration...................................................... 549
12.8 PM-LMAs with Iron Mover........................................................................................................ 555
12.9 Flux Reversal PM-LMA Tubular Configuration ..................................................................... 555
12.9.1 The Analytical Model ................................................................................................... 555
12.10 Control of PM-LMAs...................................................................................................................560
12.10.1 Electrical Control ..........................................................................................................560
12.10.2 Spark-Ignited Gasoline Linear Engine Model .......................................................... 562
12.10.3 Note on Stirling Engine LMA Stability...................................................................... 562
12.11 Progressive-Motion LMAs for Maglevs with Active Guideway............................................ 563
12.11.1 Note on Magnetohydrodynamic Linear Generators...............................................566
12.12 Summary........................................................................................................................................566
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University Politehnica Timisoara
Timisoara, Romania
MATLAB® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not warrant the accuracy of the text or exercises in this book. This book’s use or discussion of MATLAB® software or related products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular use of the MATLAB® software.
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2016 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Version Date: 20150817
International Standard Book Number-13: 978-1-4987-2358-9 (eBook - PDF)
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the valid-ity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or uti-lized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopy-ing, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923,
978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For
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Visit the Taylor & Francis Web site at
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and the CRC Press Web site at
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Contents
Preface to the Second Edition ............................................................................... xiii
Preface to the First Edition ..................................................................................... xv
Author..................................................................................................................... xix
1 Wound-Rotor Induction Generators: Steady State
1.1 Introduction .......................................................................................................................................1
1.2 Construction Elements.................................................................................................................... 3
1.2.1 Magnetic Cores
1.2.2 Windings and Their Magnetomotive Forces................................................................. 5
1.2.3 Slip-Rings and Brushes..................................................................................................... 8
1.3 Steady-State Equations..................................................................................................................... 9
1.4 Equivalent Circuit............................................................................................................................ 11
1.5 Phasor Diagrams .............................................................................................................................13
1.6 Operation at the Power Grid..........................................................................................................18
1.6.1 Stator Power versus Power Angle...................................................................................19
1.6.2 Rotor Power versus Power Angle ...................................................................................21
1.6.3 Operation at Zero Slip (S = 0).........................................................................................21
1.7 Autonomous Operation of WRIGs.............................................................................................. 22
1.8 Operation of WRIGs in the Brushless Exciter Mode................................................................ 26
1.9 Losses and Efficiency of WRIGs....................................................................................................31
1.10 Summary.......................................................................................................................................... 32
References .........34
2 Wound-Rotor Induction Generators: Transients and Control
2.1 Introduction .................................................................................................................................... 37
2.2 WRIG Phase Coordinate Model .................................................................................................. 37
2.3 Space-Phasor Model of WRIG......................................................................................................40
2.4 Space-Phasor Equivalent Circuits and Diagrams...................................................................... 42
2.5 Approaches to WRIG Transients.................................................................................................46
2.6 Static Power Converters for WRIGs............................................................................................ 47
2.6.1 Direct AC–AC Converters............................................................................................. 50
2.6.2 DC Voltage Link AC–AC Converters........................................................................... 52
2.7 Vector Control of WRIG at Power Grid...................................................................................... 54
2.7.1 Principles of Vector Control of Machine (Rotor)-Side Converter........................... 54
2.7.2 Vector Control of Source-Side Converter.................................................................... 57
2.7.3 Wind Power WRIG Vector Control at the Power Grid............................................. 59
2.7.3.1 Wind Turbine Model .................................................................................... 59
2.7.3.2 Supply-Side Converter Model.......................................................................61
2.7.3.3 Generator-Side Converter Model................................................................ 62
2.7.3.4 Simulation Results......................................................................................... 63
2.7.3.5 Three-Phase Short Circuit on the Power Grid.......................................... 65
2.7.3.6 Mechanism to Improve Performance during Fault ................................. 67
2.8 Direct Power Control of WRIG at Power Grid .......................................................................... 68
2.8.1 Concept of DPC
2.9 Independent Vector Control of Positive and Negative Sequence Currents........................... 74
2.10 Motion-Sensorless Control ........................................................................................................... 76
2.11 Vector Control in Stand-Alone Operation ................................................................................. 79
2.12 Self-Starting, Synchronization, and Loading at the Power Grid ............................................ 80
2.13 Voltage and Current Low-Frequency Harmonics of WRIG.................................................... 83
2.14 Ride-Through Control of DFIG under Unbalanced Voltage Sags .......................................... 86
2.15 Stand-Alone DFIG Control under Unbalanced Nonlinear Loads.......................................... 89
2.16 Summary...........................................................................................................................................91
3 Wound-Rotor Induction Generators: Design and Testing
3.1 Introduction .................................................................................................................................... 95
3.2 Design Specifications: An Example .............................................................................................96
3.3 Stator Design ...................................................................................................................................96
3.4 Rotor Design...................................................................................................................................103
3.5 Magnetization Current.................................................................................................................106
3.6 Reactances and Resistances .........................................................................................................109
3.7 Electrical Losses and Efficiency................................................................................................... 113
3.8 Testing of WRIGs.......................................................................................................................... 115
3.9 Summary.........................................................................................................................................116
4 Self-Excited Induction Generators
4.1 Introduction ................................................................................................................................... 119
4.2 Principle of Cage-Rotor Induction Machine............................................................................. 119
4.3 Self-Excitation: A Qualitative View............................................................................................122
4.4 Steady-State Performance of Three-Phase SEIGs.....................................................................123
4.4.1 Second-Order Slip Equation Methods........................................................................124
4.4.2 SEIGs with Series Capacitance Compensation..........................................................128
4.5 Performance Sensitivity Analysis ...............................................................................................128
4.5.1 For Constant Speed........................................................................................................129
4.5.2 For Unregulated Prime Movers ...................................................................................130
4.6 Pole Changing SEIGs for Variable Speed Operation ............................................................... 131
4.7 Unbalanced Operation of Three-Phase SEIGs..........................................................................133
4.8 One Phase Open at Power Grid...................................................................................................136
4.9 Three-Phase SEIG with Single-Phase Output ...........................................................................138
4.10 Two-Phase SEIGs with Single-Phase Output ............................................................................142
4.11 Three-Phase SEIG Transients ......................................................................................................145
4.12 Parallel Connection of SEIGs......................................................................................................148
4.13 Direct Connection to Grid Transients in Cage-Rotor Induction Generators......................150
4.14 More on Power Grid Disturbance Transients in Cage-Rotor Induction
Generators
4.15 Summary.........................................................................................................................................160
5 Stator-Converter-Controlled Induction Generators
5.1 Introduction ...................................................................................................................................165
5.2 Grid-Connected SCIGs: The Control System............................................................................166
5.2.1 Machine-Side PWM Converter Control.....................................................................166
5.2.1.1 State Observers for DTFC of SCIGs ..........................................................167
5.2.1.2 DTFC–SVM Block .......................................................................................173
5.2.2 Grid-Side Converter Control........................................................................................176
5.3 Grid Connection and Four-Quadrant Operation of SCIGs ...................................................176
5.4 Stand-Alone Operation of SCIG..................................................................................................179
5.5 Parallel Operation of SCIGs.........................................................................................................180
5.6 Static Capacitor Exciter Stand-Alone IG for Pumping Systems............................................. 181
5.7 Operation of SCIGs with DC Voltage-Controlled Output......................................................184
5.8 Stand-Alone SCIG with AC Output and Low Rating PWM Converter ...............................187
5.9 Dual Stator Winding for Grid Applications..............................................................................187
5.10 Twin Stator Winding SCIG with 50% Rating Inverter and Diode Rectifier........................189
5.11 Dual Stator Winding IG with Nested Cage Rotor....................................................................190
5.12 Summary.........................................................................................................................................190
6 Automotive Claw-Pole-Rotor Generator Systems
6.1 Introduction ...................................................................................................................................195
6.2 Construction and Principle..........................................................................................................195
6.3 Magnetic Equivalent Circuit Modeling ....................................................................................200
6.4 Three-Dimensional Finite Element Method Modeling .......................................................... 203
6.5 Losses, Efficiency, and Power Factor ......................................................................................... 208
6.6 Design Improvement Steps ..........................................................................................................210
6.6.1 Claw-Pole Geometry ......................................................................................................210
6.6.2 Booster Diode Effects..................................................................................................... 211
6.6.3 Assisting Permanent Magnets......................................................................................212
6.6.4 Increasing the Number of Poles...................................................................................213
6.6.5 Winding Tapping (Reconfiguration)...........................................................................213
6.6.6 Claw-Pole Damper .........................................................................................................216
6.6.7 Controlled Rectifier........................................................................................................216
6.7 Lundell Starter/Generator for Hybrid Vehicles.........................................................................217
6.8 IPM Claw-Pole Alternator System for More Vehicle Braking Energy Recuperation:
A Case Study
6.8.1 3D Nonlinear Magnetic Circuit Model...................................................................... 225
6.8.1.1 Evaluation Design Calibration.................................................................. 226
6.8.2 Optimal Design: Method, Code, and Sample Results with Prototype
Test Results
6.8.3 3D-FEM Analysis.......................................................................................................... 229
6.8.4 Vehicle Braking Energy Recuperation Scheme and Its Control ............................ 232
6.8.4.1 Dynamic Model of the Proposed System ................................................ 233
6.8.4.2 42 VDC Storage Battery Model.................................................................... 236
6.8.4.3 Control Strategy........................................................................................... 237
6.8.4.4 Simulation Results....................................................................................... 238
6.8.5 Extension of IPM Alternator Utilization up to 100 kW Systems............................241
6.9 Summary.........................................................................................................................................241
References
7 Induction Starter/Alternators for Electric Hybrid Vehicles
7.1 Electric Hybrid Vehicle Configuration ..................................................................................... 245
7.2 Essential Specifications................................................................................................................ 248
7.2.1 Peak Torque (Motoring) and Power (Generating)................................................... 248
7.2.2 Battery Parameters and Characteristics.................................................................... 250
7.3 Topology Aspects of Induction Starter/Alternator.................................................................. 253
7.4 ISA Space-Phasor Model and Characteristics.......................................................................... 255
7.5 Vector Control of ISA................................................................................................................... 263
7.6 DTFC of ISA..................................................................................................................................264
7.7 ISA Design Issues for Variable Speed........................................................................................266
7.7.1 Power and Voltage Derating ........................................................................................266
7.7.2 Increasing Efficiency..................................................................................................... 267
7.7.3 Increasing the Breakdown Torque..............................................................................268
7.7.4 Additional Measures for Wide Constant Power Range...........................................269
7.7.4.1 Winding Reconfiguration.......................................................................... 270
7.8 Summary........................................................................................................................................ 273
8 Permanent-Magnet-Assisted Reluctance Synchronous Starter/
Alternators for Electric Hybrid Vehicles
8.1 Introduction .................................................................................................................................. 279
8.2 Topologies of PM-RSM................................................................................................................280
8.3 Finite Element Analysis............................................................................................................... 283
8.3.1 Flux Distribution........................................................................................................... 283
8.3.2 dq Inductances
8.3.3 Cogging Torque
8.3.4 Core Losses Computation by FEM............................................................................. 289
8.4 dq Model of PM-RSM ...................................................................................................................291
8.5 Steady-State Operation at No Load and Symmetric Short Circuit....................................... 297
8.5.1 Generator No-Load....................................................................................................... 297
8.5.2 Symmetrical Short Circuit........................................................................................... 297
8.6 Design Aspects for Wide Speed Range Constant Power Operation.....................................299
8.7 Power Electronics for PM-RSM for Automotive Applications.............................................. 305
8.8 Control of PM-RSM for EHV ..................................................................................................... 307
8.9 State Observers without Signal Injection for Motion Sensorless Control ............................310
8.10 Signal Injection Rotor Position Observers.................................................................................312
8.11 Initial and Low-Speed Rotor Position Tracking .......................................................................313
8.12 50/100 kW, 1350–7000 rpm (600 Nm Peak Torque, 40 kg) PM-Assisted Reluctance
Synchronous Motor/Generator for HEV: A Case Study
8.12.1 Introduction
8.12.2 General Design Summary and Results.......................................................................318
8.12.2.1 Stator Core Geometry..................................................................................318
8.12.2.2 Number of Turns per Coil nc ......................................................................319
8.12.2.3 The Stator Leakage Inductance Ls1
and Ldm/Lqm Requirements.............319
8.12.2.4 Rotor Lamination Design........................................................................... 320
8.12.2.5 Peak Torque Production............................................................................. 320
8.12.2.6 Slot Area/Peak Current Density/Stator Resistance Rs ............................321
8.12.2.7 Weights of Active Materials........................................................................321
8.12.2.8 Performance at 100 kW and 7000 rpm..................................................... 322
8.12.2.9 Performance at 50 kW, 7000 rpm, and 1350 rpm.................................... 323
8.12.2.10 Equivalent Circuit ....................................................................................... 323
8.12.3 Optimal Design Methodology and Results............................................................... 324
8.12.3.1 IPMSM—Analytical Model ....................................................................... 324
8.12.3.2 Optimal Design of IPMSM........................................................................ 324
8.12.4 FEM Validation without and with Rotor Segmentation ......................................... 327
8.12.5 Dynamic Model and Vector Control Performance Validation.............................. 330
8.13 Summary.........................................................................................................................................333
9 Switched Reluctance Generators and Their Control
9.1 Introduction .................................................................................................................................. 339
9.2 Practical Topologies and Principles of Operation................................................................... 339
9.2.1 kW/Peak kVA Ratio.......................................................................................................344
9.3 SRG(M) Modeling ........................................................................................................................346
9.4 Flux/Current/Position Curves....................................................................................................348
9.5 Design Issues................................................................................................................................. 349
9.5.1 Motor and Generator Specifications .......................................................................... 350
9.5.2 Number of Phases, Stator and Rotor Poles: m, Ns, Nr ...............................................351
9.5.3 Stator Bore Diameter Dis and Stack Length ...............................................................351
9.5.4 Number of Turns per Coil Wc for Motoring.............................................................. 353
9.5.5 Current Waveforms for Generator Mode .................................................................. 353
9.6 PWM Converters for SRGs ......................................................................................................... 356
9.7 Control of SRG(M)s...................................................................................................................... 358
9.7.1 Feed-Forward Torque Control of SRG(M) with Position Feedback...................... 359
9.8 Direct Torque Control of SRG(M) .............................................................................................364
9.9 Rotor Position and Speed Observers for Motion-Sensorless Control ..................................366
9.9.1 Signal Injection for Standstill Position Estimation..................................................366
9.10 Output Voltage Control in SRG.................................................................................................. 369
9.11 Double Stator SRG with Segmented Rotor............................................................................... 370
9.12 Summary.........................................................................................................................................371
10 Permanent Magnet Synchronous Generator Systems
10.1 Introduction .................................................................................................................................. 377
10.2 Practical Configurations and Their Characterization............................................................ 378
10.2.1 Distributed versus Concentrated Windings ............................................................. 383
10.3 Air Gap Field Distribution, emf, and Torque........................................................................... 386
10.4 Stator Core Loss Modeling.......................................................................................................... 394
10.4.1 FEM-Derived Core Loss Formulas............................................................................. 394
10.4.2 Simplified Analytical Core Loss Formulas................................................................ 398
10.5 Circuit Model .................................................................................................................................401
10.5.1 Phase Coordinate Model...............................................................................................401
10.5.2 dq Model of PMSG ........................................................................................................402
10.6 Circuit Model of PMSG with Shunt Capacitors and AC Load ..............................................408
10.7 Circuit Model of PMSG with Diode Rectifier Load.................................................................410
10.8 Utilization of Third Harmonic for PMSG with Diode Rectifiers........................................... 411
10.9 Autonomous PMSGs with Controlled Constant Speed and AC Load..................................415
10.10 Grid-Connected Variable-Speed PMSG System.......................................................................418
10.10.1 Diode Rectifier and Boost DC–DC Converter Case................................................420
10.11 PM Genset with Multiple Outputs.............................................................................................422
10.12 Super-High-Speed PM Generators: Design Issues..................................................................426
10.12.1 Rotor Sizing
10.13 Super-High-Speed PM Generators: Power Electronics Control Issues................................ 432
10.14 Design of a 42 VDC Battery-Controlled-Output PMSG System.............................................434
10.14.1 Design Initial Data ........................................................................................................ 435
10.14.2 Minimum Speed: nmin ................................................................................................... 435
10.14.3 Number of Poles: 2p1 ..................................................................................................... 437
10.14.4 Rotor Configuration...................................................................................................... 437
10.14.5 Stator Winding Type..................................................................................................... 438
10.14.6 Winding Tapping .......................................................................................................... 439
10.14.7 PMSG Current Waveform............................................................................................440
10.14.8 Diode Rectifier Imposes Almost Unity Power Factor.............................................440
10.14.9 Peak Torque-Based Sizing............................................................................................440
10.14.10 Generator-to-DC Voltage Relationships....................................................................440
10.14.11 ΨPM, Ls, and Rs
10.15 Methods for Testing PMSGs.......................................................................................................443
10.15.1 Standstill Tests
10.15.2 No-Load Generator Tests.............................................................................................447
10.15.3 Short-Circuit Generator Tests.....................................................................................448
10.15.4 Stator Leakage Inductance and Skin Effect...............................................................448
10.15.5 Motor No-Load Test......................................................................................................450
10.15.6 Generator Load Tests....................................................................................................450
10.16 Grid to Stand-Alone Transition Motion-Sensorless Dual-Inverter Control
of PMSG with Asymmetrical Grid Voltage Sags and Harmonics Filtering:
A Case Study
10.16.1 Voltage Sags Ride-Through Capability ......................................................................454
10.16.1.1 Line Voltage Positive Sequence with D-Module Filter..........................456
10.16.1.2 Line Voltage Angle Estimation ................................................................. 457
10.16.2 Stand-Alone PMSG Control: Harmonic and Negative-Sequence Voltage
Compensation under Nonlinear Load
10.16.3 Seamless Switching Transfer from Stand-Alone to Grid (and Back).................... 458
10.16.3.1 Transition from Stand-Alone to Grid-Connected Mode...................... 459
10.16.3.2 Transition from Grid-Connected to Stand-Alone Mode......................460
10.16.4 PMSG Motion-Sensorless Control System................................................................460
10.16.4.1 PMSG Modeling ..........................................................................................460
10.16.4.2 Active Power and Current Control............................................................461
10.16.4.3 Rotor Position and Speed Observer..........................................................463
10.16.5 Test Platform and Experimental Results...................................................................464
10.16.5.1 Voltage Sags Ride-Through........................................................................464
10.16.5.2 Harmonic and Negative-Sequence Voltage Compensation
under Nonlinear Load
10.16.5.3 Transition from Stand-Alone to Grid-Connected Mode......................467
10.16.5.4 Transition from Grid-Connected to Stand-Alone Mode......................469
10.16.6 Conclusion
10.17 Note on Medium-Power Vehicular Electric Generator Systems............................................471
10.18 Summary........................................................................................................................................ 472
11 Transverse Flux and Flux Reversal Permanent Magnet Generator Systems
11.1 Introduction ..................................................................................................................................479
11.2 Three-Phase Transverse Flux Machine: Magnetic Circuit Design .......................................485
11.2.1 Phase Inductance Ls ......................................................................................................489
11.2.2 Phase Resistance and Slot Area ...................................................................................490
11.3 TFM: The dq Model and Steady State........................................................................................ 493
11.4 Three-Phase FR-PM Generator: Magnetic and Electric Circuit Design
11.4.1 Preliminary Geometry for 200 Nm at 128 rpm via Conceptual Design...............499
11.4.2 FEM Analysis of Pole-PM FRM at No Load .............................................................500
11.4.3 FEM Analysis at Steady State on Load....................................................................... 502
11.4.4 FEM Computation of Inductances............................................................................. 508
11.4.5 Inductances and the Circuit Model of FRM ............................................................. 508
11.4.6 dq Model of FRM............................................................................................................510
11.4.7 Notes on Flux Reversal Generator Control................................................................517
11.5 High Power Factor Vernier PM Generators ..............................................................................521
11.5.1 Power Factor of VPM Machine ....................................................................................521
11.5.1.1 Power Factor..................................................................................................521
11.5.2 DSSA: VPM for Higher Power Factor........................................................................ 523
11.6 Summary........................................................................................................................................ 525
\12 Linear Motion Alternators
12.1 Introduction .................................................................................................................................. 529
12.2 LMA Principle of Operation....................................................................................................... 529
12.2.1 Motion Equation............................................................................................................ 532
12.3 PM-LMA with Coil Mover...........................................................................................................533
12.4 Multipole LMA with Coil Plus Iron Mover.............................................................................. 535
12.5 PM-Mover LMAs...........................................................................................................................541
12.6 Tubular Homopolar PM Mover Single-Coil LMA..................................................................544
12.7 Flux Reversal LMA with Mover PM Flux Concentration...................................................... 549
12.8 PM-LMAs with Iron Mover........................................................................................................ 555
12.9 Flux Reversal PM-LMA Tubular Configuration ..................................................................... 555
12.9.1 The Analytical Model ................................................................................................... 555
12.10 Control of PM-LMAs...................................................................................................................560
12.10.1 Electrical Control ..........................................................................................................560
12.10.2 Spark-Ignited Gasoline Linear Engine Model .......................................................... 562
12.10.3 Note on Stirling Engine LMA Stability...................................................................... 562
12.11 Progressive-Motion LMAs for Maglevs with Active Guideway............................................ 563
12.11.1 Note on Magnetohydrodynamic Linear Generators...............................................566
12.12 Summary........................................................................................................................................566
DOWNLOAD: Second Edition - VARIABLE SPEED GENERATORS
Monopoly: Power Efficiency Guide
Preface to the Second Edition
The first edition of this single-author, two-book set was published in 2006. Since then, electric energy,“produced” mostly via electric generators, has become one of the foremost activities in our global econ-
omy world. The subject of electric generators (Synchronous Generators and Variable Speed Generators as
two books) attracted special attention worldwide both from industry and academia in the last decade.
Electric generators’ design and control may constitute a new graduate course in universities with electric
power programs.
Also, in the design and control of electric generators for applications ranging from energy conversion
to electric vehicles (transportation) and auxiliary power sources, new knowledge and developments
have been published in the last ten years. In the last ten years, in wind generators alone, the installed
power has increased from some 40,000 MW to 300,000 MW (in 2014).
In view of these developments, we decided to come up with a new edition that
• Keeps the structure of the first edition to avoid confusion for users
• Keeps the style with many numerical worked-out examples of practical interest, together with
more complete case studies
• Includes text and number corrections
• Adds quite a few new paragraphs in both books, totaling around 100 pages, to illustrate syntheti-
cally the progress in the field in the last decade
DOWNLOAD: Second Edition - VARIABLE SPEED GENERATORS
Learn more: Earth Magnetism - A Guided Tour through Magnetic Fields
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