Electric Generators Handbook - Two Volume Set

Contents Preface to the Third Edition Preface to the Second Edition.............................................................................................xiii Preface to the First Edition..................................................................................................xv Author..................................................................................................................................xix S.G. 1 Electric Energy and Electric Generators 1.1 Introduction...............................................................................................................................................1 1.2 Major Energy Sources...............................................................................................................................3 1.3 Electric Power Generation Limitations.....................................................................................................4 1.4 Electric Power Generation........................................................................................................................4 1.5 From Electric Generators to Electric Loads.............................................................................................7 1.6 Summary..................................................................................................................................................12 References ………………………………………………………………………………………………… 12 2 Principles of Electric Generators 2.1 Three Types of Electric Generators..........................................................................................................13 2.2 Synchronous Generators...........................................................................................................................15 2.3 Permanent Magnet Synchronous Generators.......................................................................................... 20 2.4 Homopolar Synchronous Generator........................................................................................................ 23 2.5 Induction Generator................................................................................................................................. 25 2.6 Wound-Rotor (DFIG) Doubly-Fed Induction Generator.........................................................................28 2.7 Parametric Generators..............................................................................................................................30 2.7.1 Flux Reversal Generators..................................................................................................................... 32 2.7.2 Transverse Flux Generators...................................................................................................................34 2.7.3 Linear Motion Alternators.................................................................................................................... 34 2.8 Electric Generator Applications.............................................................................................................. 39 2.9 High-Power Wind Generators............................................................................................................. …39 2.9.1 Introduction ……………………………………………………………………….………………… 39 2.9.2 DC Excited Synchronous Generator Systems...................................................................................... 45 2.9.2.1 Brushless Excitation.......................................................................................................................... 45 2.9.2.2 Lower Size (Weight) by Optimal Design...........................................................................................46 2.9.2.3 DD Superconducting Synchronous Generators................................................................................. 47 2.9.2.4 Claw Pole 1G-dceSG (3 MW, 75 rpm)..............................................................................................48 2.9.2.5 Windformer....................................................................................................................................... 50 2.9.3 Less-PM PMSGs ……………………………………………………………………………………..…………………….…50 2.9.3.1 Ferrite TF-PMSG with Axial Air Gap...............................................................................................51 2.9.3.2 High Speed Modular PMSG (4 × 0.75 MW, 4000 rpm).................................................................. 52 2.9.3.3 Flux Reversal PMSGs....................................................................................................................... 53 2.9.3.4 The Vernier Machine........................................................................................................................ 54 2.9.4 Multiple Phase Reluctance Generators (BLDC-MRG)....................................................................... 55 2.9.5 DFIG: Brushless?.................................................................................................................................57 2.9.6 Brushless Doubly Fed Reluctance (or Induction) Generators..............................................................59 2.9.7 Switched Reluctance Generators Systems............................................................................................61 2.9.7.1 DD-SRG.............................................................................................................................................61 2.9.7.2 High Speed Wind SRG..................................................................................................................... 62 2.9.8 Flux-Switch Ferrite PM Stator Generators.......................................................................................... 63 2.10 Summary................................................................................................................................................66 References ………………………………………………………………………………………………….66 3 Prime Movers 3.1 Introduction..............................................................................................................................................71 3.2 Steam Turbines.........................................................................................................................................73 3.3 Steam Turbine Modeling......................................................................................................................... 75 3.4 Speed Governors for Steam Turbines.......................................................................................................79 3.5 Gas Turbines..............................................................................................................................................81 3.6 Diesel Engines.......................................................................................................................................... 83 3.6.1 Diesel Engine Operation........................................................................................................................ 83 3.6.2 Diesel Engine Modeling................................................................................................... …………….85 3.7 Stirling Engines.........................................................................................................................................87 3.7.1 Summary of Thermodynamic Basic Cycles...........................................................................................87 3.7.2 Stirling-Cycle Engine.............................................................................................................................90 3.7.3 Free-Piston Linear-Motion Stirling Engines Modeling..........................................................................91 3.8 Hydraulic Turbines....................................................................................................................................94 3.8.1 Hydraulic Turbines Basics..................................................................................................................... 95 3.8.2 First-Order Ideal Model for Hydraulic Turbines................................................................................... 98 3.8.3 Second and Higher Order Models of Hydraulic Turbines................................................................... 101 3.8.4 Hydraulic Turbine Governors...............................................................................................................104 3.8.5 Reversible Hydraulic Machines............................................................................................................106 3.9 Wind Turbines.........................................................................................................................................109 3.9.1 Principles and Efficiency of Wind Turbines........................................................................................111 3.9.2 Steady-State Model of Wind Turbines.................................................................................................114 3.9.3 Wind Turbine Models for Control........................................................................................................118 3.9.3.1 Unsteady Inflow Phenomena in Wind Turbines................................................................................119 3.9.3.2 Pitch-Servo and Turbine Model.........................................................................................................119 3.10 New, advanced pitch control of wind turbines: a review 3.11 Summary................................................................................................................................................121 References ……………………………………………………………………………………………….…123 4 Large and Medium Power Synchronous Generators: Topologies and Steady State 4.1 Introduction...............................................................................................................................................125 4.2 Construction Elements..............................................................................................................................125 4.2.1 Stator Windings ……………………………………………………………………………………….127 4.3 Excitation Magnetic Field.........................................................................................................................132 4.4 Two-Reaction Principle of Synchronous Generators................................................................................136 4.5 Armature Reaction Field and Synchronous Reactances............................................................................138 4.6 Equations for Steady State with Balanced Load.......................................................................................142 4.7 Phasor Diagram.........................................................................................................................................144 4.8 Inclusion of Core Losses in the Steady-State Model.................................................................................145 4.9 Autonomous Operation of Synchronous Generators.................................................................................150 4.9.1 No Load Saturation Curve: E1(If); n = ct, I1 = 0......................................................................................150 4.9.2 Short Circuit Saturation Curve I1 = f(If); V1 = 0, n1 = nr = ct....................................................................156 4.9.3 Zero Power Factor Saturation Curve V1(IF); I1 = ct, cos φ1 = 0, n1 = nr...................................................158 4.9.4 V1–I1 Characteristic, IF = ct, cos φ1 = ct, n1 = nr.......................................................................................159 4.10 SG Operation at Power Grid (in Parallel)................................................................................................160 4.10.1 Power/Angle Characteristic: Pe (δV)..............................................................................………….……161 4.10.2 V-Shape Curves: I1(IF), P1 = ct, V1 = ct, n = ct.......................................................................................163 4.10.3 Reactive Power Capability Curves........................................................................................................164 4.10.4 Defining Static and Dynamic Stability of SGs......................................................................................165 4.11 Unbalanced Load Steady-State Operation................................................................................................168 4.12 Measuring Xd, Xq, Z−, Z0............................................................................................................................170 4.13 Phase-to-Phase Short Circuit....................................................................................................................172 4.14 Synchronous Condenser...........................................................................................................................177 4.15 PM-Assisted DC Excited Salient Pole Synchronous Generators.............................................................178 4.16 Multiphase Synchronous Machine Inductances via Winding Function Method..................................... 181 4.17 Contactless power transfer to SG rotors: inductive and capacitive 4.18 Summary...................................................................................................................................................183 References………………………………………………………………………………………………….... 185 5 Synchronous Generators: Modeling for Transients 5.1 Introduction.................................................................................................................................................187 5.2 Phase-Variable Model..................................................................................................................................188 5.3 d–q Model....................................................................................................................................................193 5.4 Per Unit (P.U.) dq Model.............................................................................................................................201 5.5 Steady State via the d–q Model....................................................................................................................203 5.6 General Equivalent Circuits.........................................................................................................................207 5.7 Magnetic Saturation Inclusion in the d–q Model.........................................................................................209 5.7.1 The Single d–q Magnetization Curves Model..........................................................................................209 5.7.2 Multiple d–q Magnetization Curves Model..............................................................................................213 5.8 Operational Parameters................................................................................................................................214 5.8.1 Electromagnetic Transients.......................................................................................................................216 5.8.2 Sudden Three-Phase Short Circuit from No Load....................................................................................218 5.9 Standstill Time Domain Response Provoked Transients.............................................................................222 5.10 Standstill Frequency Response..................................................................................................................226 5.10.1 Asynchronous Running...........................................................................................................................227 5.11 Simplified Models for Power System Studies............................................................................................233 5.11.1 Neglecting the Stator Flux Transients.....................................................................................................233 5.11.2 Neglecting the Stator Transients and the Rotor Damper Winding Effects..............................................234 5.11.3 Neglecting All Electrical Transients........................................................................................................234 5.12 Mechanical Transients................................................................................................................................235 5.12.1 Response to Step Shaft Torque Input......................................................................................................236 5.12.2 Forced Oscillations..................................................................................................................................236 5.13 Small Disturbance Electromechanical Transients......................................................................................239 5.14 Large Disturbance Transients Modeling....................................................................................................242 5.14.1 Line to Line Fault....................................................................................................................................245 5.14.2 Line to Neutral Fault...............................................................................................................................246 5.15 Finite Element SG Modeling......................................................................................................................246 5.16 SG Transient Modeling for Control Design...............................................................................................249 5.17 Summary.....................................................................................................................................................251 References …………………………………………………………………………………………………….255 6 Control of Synchronous Generators in Power Systems 6.1 Introduction....................................................................................................................................………..257 6.2 Speed Governing Basics..............................................................................................................................259 6.3 Time Response of Speed Governors...........................................................................................………….263 6.4 Automatic Generation Control...................................................................................................……….….265 6.5 Time Response of Speed (Frequency) and Power Angle...........................................................…………..267 6.6 Voltage and Reactive Power Control Basics................................................................................................270 6.7 Automatic Voltage Regulation Concept.......................................................................................................271 6.8 Exciters ………………………………………………………………………………..…………………..272 6.8.1 AC Exciters ……………………………………………………………………………………………...273 6.8.2 Static Exciters …………………………………………………………………………………………...274 6.9 Exciter’s Modeling.......................................................................................................................................275 6.9.1 New PU System …………………………………………………………………………………………276 6.9.2 DC Exciter Model......................................................................................................................................277 6.9.3 AC Exciter ………………………………………………………………………………………………280 6.9.4 Static Exciter ………………………………………………………………………………………...….282 6.10 Basic AVRs................................................................................................................................................283 6.11 Underexcitation Voltage.............................................................................................................................287 6.12 Power System Stabilizers...........................................................................................................................288 6.13 Coordinated AVR-PSS and Speed Governor Control................................................................................291 6.14 FACTS-Added Control of SG...................................................................................................... ……….292 6.14.1 Series Compensators...............................................................................................................................296 6.14.2 Phase-Angle Regulation and Unit Power Flow Control.........................................................................297 6.15 Subsynchronous Oscillations.....................................................................................................................298 6.15.1 Multi-Mass Shaft Model.........................................................................................................................298 6.15.2 Torsional Natural Frequency..................................................................................................................300 6.16 Subsynchronous Resonance.......................................................................................................................301 6.17 Note on Autonomous Synchronous Generators’ Control..........................................................................302 6.17.1 Variable Frequency/Speed SG with Brushless Exciter...........................................................................303 6.18 Aircraft brushless d.c. excited starter/generator systems: recent progress 6.19 Full size converter operation of SG/m in large pump storage systems 6.20 Summary References 7 Design of Synchronous Generators 7.1 Introduction....................................................................................................................................313 7.2 Specifying Synchronous Generators for Power Systems...............................................................313 7.2.1 Short Circuit Ratio.......................................................................................................................314 7.2.2 SCR and xd′ Impact on Transient Stability.................................................................................314 7.2.3 Reactive Power Capability and Rated Power Factor...................................................................315 7.2.4 Excitation Systems and Their Ceiling Voltage............................................................................316 7.2.4.1 Voltage and Frequency Variation Control................................................................................316 7.2.4.2 Negative Phase Sequence Voltage and Currents......................................................................317 7.2.4.3 Harmonic Distribution..............................................................................................................317 7.2.4.4 Temperature Basis for Rating...................................................................................................318 7.2.4.5 Ambient: Following Machines.................................................................................................318 7.2.4.6 Reactances and Unusual Requirements....................................................................................318 7.2.4.7 Start–Stop Cycles......................................................................................................................319 7.2.4.8 Starting and Operation as a Motor............................................................................................319 7.2.4.9 Faulty Synchronization............................................................................................................ 320 7.2.4.10 Forces ……………………………………………………………………………………….320 7.2.4.11 Armature Voltage................................................................................................................... 320 7.2.4.12 Runaway Speed.......................................................................................................................321 7.2.4.13 Design Issues...........................................................................................................................321 7.3 Output Power Coefficient and Basic Stator Geometry....................................................................321 7.4 Number of Stator Slots....................................................................................................................325 7.5 Design of Stator Winding................................................................................................................328 7.6 Design of Stator Core.....................................................................................................................333 7.6.1 Stator Stack Geometry.................................................................................................................335 7.7 Salient: Pole Rotor Design..............................................................................................................339 7.8 Damper Cage Design......................................................................................................................343 7.9 Design of Cylindrical Rotors..........................................................................................................344 7.10 Open Circuit Saturation Curve......................................................................................................348 7.11 On-Load Excitation m.m.f. F1n.....................................................................................................353 7.11.1 Potier Diagram Method..............................................................................................................354 7.11.2 Partial Magnetization Curve Method.........................................................................................355 7.12 Inductances and Resistances.........................................................................................................359 7.12.1 Magnetization Inductances Lad, Laq............................................................................................359 7.12.2 Stator Leakage Inductance Lsl....................................................................................................360 7.13 Excitation Winding Inductances...................................................................................................362 7.14 Damper Winding Parameters........................................................................................................364 7.15 Solid Rotor Parameters..................................................................................................................365 7.16 SG Transient Parameters and Time Constants..............................................................................367 7.16.1 Homopolar Reactance and Resistance.......................................................................................368 7.17 Electromagnetic Field Time Harmonics........................................................................................370 7.18 Slot Ripple Time Harmonics.........................................................................................................372 7.19 Losses and Efficiency....................................................................................................................373 7.19.1 No Load Core Losses of Excited SGs........................................................................... ………374 7.19.2 No Load Losses in the Stator Core End Stacks.......................................................... ………...376 7.19.3 Short Circuit Losses................................................................................................................... 377 7.19.4 Third Flux Harmonic Stator Teeth Losses.................................................................. ………...379 7.19.5 No Load and On Load Solid Rotor Surface Losses................................................................... 380 7.19.6 Excitation Losses............................................................................................................ ………383 7.19.7 Mechanical Losses.......................................................................................................... ………383 7.19.8 SG Efficiency …………………………………………………………………………………. 385 7.20 Exciter Design Issues..................................................................................................................... 386 7.20.1 Excitation Rating........................................................................................................................ 388 7.20.2 Sizing the Exciter...................................................................................................................... 388 7.20.3 Note on Thermal and Mechanical Design................................................................................ .389 7.21 Optimization Design Issues......................................................................................................... .389 7.21.1 Optimal Design of a Large Wind Generator by Hooke–Jeeves Method....................................391 7.21.2 Magnetic Equivalent Circuit (MEC) Population–Based Optimal Design of SG.......................392 7.22 Generator/Motor Issues................................................................................................................ 394 7.23 ALA rotor RSG of 10 MW, 480 rpm: preliminary design with key FEM validations: a case study 7.24 Summary 8 Testing of Synchronous Generators 8.1 Acceptance Testing.........................................................................................................................405 8.1.1 A1. Insulation Resistance Testing................................................................................................406 8.1.2 A2. Dielectric and Partial Discharge Tests..................................................................................406 8.1.3 A3. Resistance Measurement.......................................................................................................406 8.1.4 A4–5. Tests for Short-Circuited Field Turns and Polarity...........................................................406 8.1.5 A6. Shaft Current and Bearing Insulation....................................................................................407 8.1.6 A7. Phase Sequence......................................................................................................................407 8.1.7 A8. Telephone Influence Factor (TIF)..........................................................................................408 8.1.8 A9. Balanced Telephone-Influence Factor...................................................................................408 8.1.9 A10. Residual-Component Telephone-Influence Factor..............................................................408 8.1.10 A11. Line to Neutral Telephone Influence Factor......................................................................408 8.1.11 A12. Stator Terminal Voltage Waveform Deviation and Distortion Factor...............................409 8.1.12 A12. Over-Speed Tests...............................................................................................................410 8.1.13 A13. Line Charging....................................................................................................................410 8.1.14 A14. Acoustic Noise.................................................................................................................. 411 8.2 Testing for Performance (Saturation Curves, Segregated Losses, and Efficiency)........................ 411 8.2.1 Separate-Driving for Saturation Curves and Losses.................................................................... 411 8.2.2 Electric Input (Idle-Motoring) Method for Saturation Curves and Losses...................................414 8.2.3 Retardation (Free Deceleration Tests)..........................................................................................417 8.3 Excitation Current under Load and Voltage Regulation..................................................................418 8.3.1 The Armature Leakage Reactance................................................................................................419 8.3.2 Potier Reactance ………………………………………………………………………………...420 8.3.3 Excitation Current for Specified Load..........................................................................................421 8.3.4 Excitation Current for Stability Studies........................................................................................422 8.3.5 Temperature Tests........................................................................................................................ 423 8.3.5.1 Conventional Loading............................................................................................................... 423 8.3.5.2 Synchronous Feedback (Back to Back) Loading Testing......................................................... 423 8.3.5.3 Zero Power Factor Load Test.....................................................................................................424 8.4 Need for Determining Electrical Parameters................................................................................... 425 8.5 Per Unit Values.................................................................................................................................426 8.6 Tests for Parameters under Steady State..........................................................................................428 8.6.1 Xdu, Xds Measurements...................................................................................................................429 8.6.2 Quadrature-Axis Magnetic Saturation Xq from Slip Tests............................................................429 8.6.2.1 Slip Test ………………………………………………………………………………………430 8.6.2.2 Quadrature Axis (Reactance) Xq from Maximum Lagging Current Test...................................430 8.6.3 Negative Sequence Impedance Z2.................................................................................................431 8.6.4 Zero Sequence Impedance Zo....................................................................................................... 433 8.6.5 Short Circuit Ratio........................................................................................................................434 8.6.6 Angle δ, Xds, Xqs Determination from Load Tests..........................................................................435 8.6.7 Saturated Steady-State Parameters from Standstill Flux Decay Tests..........................................436 8.7 Tests to Estimate the Subtransient and Transient Parameters..........................................................440 8.7.1 Three Phase Sudden Short Circuit Tests.......................................................................................440 8.7.2 Field Sudden Short Circuit Tests with Open Stator Circuit..........................................................441 8.7.3 The Short Circuit Armature Time Constant Ta.............................................................................442 8.8 Transient and Subtransient Parameters from d and q Axis Flux Decay Test at Standstill …………………………………………………………………………..……………… .444 8.9 Subtransient Reactances from Standstill Single Frequency ac Tests...............................................445 8.10 Standstill Frequency Response Tests (SSFR)................................................................................446 8.10.1 Background ……………………………………………………………………………………446 8.10.2 From SSFR Measurements to Time Constants.......................................................................... 452 8.10.3 The SSFR Phase Method........................................................................................................... 452 8.11 Online Identification of SG Parameters.........................................................................................454 8.11.1 A Small Signal Injection on: Line Technique............................................................................ 455 8.11.2 Line Switching (On or Off) Parameter Identification for Isolated Grids.............. …………….457 8.11.3 Synthetic Back to Back Load Testing with Inverter Supply..................................... ………….458 8.12 Pole drop test, renewed: a case study 8.13 Emulation of IEEE STD 421.5/industrial excitation systems using a micro- alternator’s exciter – a case study. 8.14 High frequency response analysis (HFRA) to diagnose ground and interturn faults in salient pole large generators. 8.15 Summary References Index V.S.G. 1 Wound-Rotor Induction Generators: Steady State 1.1 Introduction...........................................................................................................................................1 1.2 Construction Elements..........................................................................................................................3 1.2.1 Magnetic Cores …………………………………………………………………………………….4 1.2.2 Windings and Their mmfs..................................................................................................................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.......................................................................................................................21 1.7 Autonomous Operation of WRIG........................................................................................................22 1.8 Operation of WRIG in the Brushless Exciter Mode............................................................................26 1.9 Losses and Efficiency of WRIG..........................................................................................................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 (DPC) of WRIG at Power Grid............................................................... ….68 2.8.1 Concept of DPC ....……………………………………………………………………….. …….69 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 Advanced control of DFIGs: recent progress 2.17 Active and reactive power control in DFIGs 2.18 DFIG control in pump storage plants 2.19 A.C. and D.C. grid forming operation mode: impedance model 2.20 The brushless DFIG and DFRG 2.21 Summary References ………………………………………………………………………………93 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 References ……………………………………………………………………………………………..117 4 Self-Excited Induction Generators 4.1 Introduction.................................................................................................................................... ..119 4.2 Cage Rotor Induction Machine Principle........................................................................................ 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………………151 4.15 Summary.........................................................................................................................................160 References ……………………………………………………………………………………………..162 5 Stator-Converter-Controlled Induction Generators (SCIGs) 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 10 MW, 10 rpm, 10 Hz directly driven induction generator (CRIG): preliminary design and key FEM validation (a case study) 5.13 Dual, power-6-phase and control -3 phase CRIG with dual-diode-rectified output for small / medium wind power: a case study 5.14 CRIG – based vehicular starter generator systems: a review 5.15 Summary..........................................................................................................................................190 References .……………………………………………………………………………………………. 192 6 Automotive Claw-Pole-Rotor Generator Systems 6.1 Introduction........................................................................................................................................195 6.2 Construction and Principle.................................................................................................................195 6.3 Magnetic Equivalent Circuit (MEC) Modeling..................................................................................200 6.4 Three-Dimensional Finite Element Method (3D FEM) 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 …………………………………………………………………………………………….225 6.8.1 3D Nonlinear Magnetic Circuit Model............................................................................................ 225 6.8.1.1 Design Calibration........................................................................................................................ 226 6.8.2 Optimal Design: Method, Code, and Sample Results with Prototype Test Results ………………………………………………………………………………………….. …227 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 ……………………………………………………………………………………………….243 7 Induction Starter/Alternators (ISAs) for Electric Hybrid Vehicles (EHVs) 7.1 EHV 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 (ISA)........................................................ ………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 References ……………………………………………………………………………………………..276 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 d–q Inductances …………………………………………………………………………….……284 8.3.3 Cogging Torque ………………………………………………………………………………….288 8.3.4 Core Losses Computation by FEM................................................................................................289 8.4 d–q 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 N m Peak Torque, 40 kg) PM-Assisted Reluctance Synchronous Motor/Generator for HEV: A Case Study ……………………………………………….317 8.12.1 Introduction ……………………………………………………………………………………..317 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 PM-assisted reluctance starter – generator system for vehicular applications by case studies 8.14 40-60 kW (600-2400 rpm) d.c. output RSG for small maritime ships 8.15 Summary...........................................................................................................................................333 References ……………………………………………………………………………………................335 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 D.C. stator excited switched reluctance starter/generator system: a case study 9.13 Dynamic performance improvement by active a.c. - d.c. reversible converter of the d.c. stator excited SRM/G: a case study 9.14 Summary..............................................................................................................................................371 References ……………………………………………………………………………….. ………………374 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 d–q 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 ……………………………………………………………………………………….426 10.12.2 Stator Sizing ……………………………………………………………………………………….429 10.12.3 Losses ……………………………………………………………………………………………...431 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 …………………………………………………………………………………….442 10.15 Methods for Testing PMSGs................................................................................................................443 10.15.1 Standstill Tests ……………………………………………………………………………………..443 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 ……………………………………………………………………………………..................453 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 ………………………………………………………………………. .457 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 ……...................466 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 ……………………………………………………………………………….....................469 10.17 Note on Medium-Power Vehicular Electric Generator Systems...............................................................471 10.18 10 MW, 10 rpm, 30 Hz spoke ferrite and bonded Nd PM rotor wind PMSG: preliminary design with FEM validation for 6 rotor variants: a case study 10.19 Smaller currents THD by robust (SM) control for PMSGs: a case study 10.20 Summary....................................................................................................................................................472 References ………………………………………………………………………………………..... ………….474 11 Transverse Flux and Flux Reversal Permanent Magnet Generator Systems 11.1 Introduction..................................................................................................................................................479 11.2 Three-Phase Transverse Flux Machine (TFM): Magnetic Circuit Design...................................................485 11.2.1 Phase Inductance Ls...................................................................................................................................489 11.2.2 Phase Resistance and Slot Area.................................................................................................................490 11.3 TFM: The d–q Model and Steady State........................................................................................................493 11.4 Three-Phase Flux Reversal Permanent Magnet Generator: Magnetic and Electric Circuit Design …………………………………………………………………………………….. …………...496 11.4.1 Preliminary Geometry for 200 N m 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 d–q Model of FRM....................................................................................................................................510 11.4.7 Notes on Flux Reversal Generator (FRG) Control....................................................................................517 11.5 High Power Factor Vernier Permanent Magnet Generators.........................................................................521 11.5.1 Power Factor of Vernier PM Machine.......................................................................................................521 11.5.1.1 Power Factor...........................................................................................................................................521 11.5.2 DSSA: VPM for Higher Power Factor......................................................................................................523 11.6 Summary.......................................................................................................................................................525 References …………………………………………………………………………………………...…………526 12 Hybrid (PM+d.c. excitation) excitation synchronous and flux-modulation generator system: recent progress 12.1 Classifications and characterization 12.1.1 HESGs with isolated PM and excitation paths 12.1.2 HESGs with common – series and parallel – magnetic flux paths 12.2 Biaxial hybrid (d.c. + PM) excitation sysnchronous generator systems (BEGA) 12.3 Stator D.C.+PM excited doubly salient HESGs 12.4 Flux-modulation (FM) HESGs 13 Linear Motion Alternators 13.1 Introduction................................................................................................................................... ………529 13.2 LMA Principle of Operation......................................................................................................... ………529 13.2.1 Motion Equation......................................................................................................................................532 13.3 PM-LMA with Coil Mover........................................................................................................................533 13.4 Multipole LMA with Coil Plus Iron Mover.................................................................................. ………535 13.5 PM-Mover LMAs.......................................................................................................................................541 13.6 Tubular Homopolar PM Mover Single-Coil LMA....................................................................................544 13.7 Flux Reversal LMA with Mover PM Flux Concentration............................................................ ………549 13.8 PM-LMAs with Iron Mover.......................................................................................................................555 13.9 Flux Reversal PM-LMA Tubular Configuration........................................................................................555 13.9.1 The Analytical Model..............................................................................................................................555 13.10 Control of PM-LMAs...............................................................................................................................560 13.10.1 Electrical Control...................................................................................................................................560 13.10.2 Spark-Ignited Gasoline Linear Engine Model.......................................................................... ………562 13.10.3 Note on Stirling Engine LMA Stability.................................................................................... ………562 13.11 Progressive-Motion LMAs for Maglevs with Active Guideway................................................. ………563 13.11.1 Note on Magnetohydrodynamic (MHD) Linear Generators..................................................................566 13.12 Optimal design of 1 phase linear oscillatory PM motor-generator series of 100 W- 2000W: a case study 13.13 Summary...................................................................................................................................................566 References …………………………………………………………………………………………………… .568 Index....................................................................................................................... …………..…………569

Biography

Prof. Ion Boldea (IEEE Life Fellow) studied at and obtained a PhD in Electrical Engineering (on linear induction motors design and control) in 1973 at University Politehnica Timisoara, Romania. He has been an active professor since 1968, having completed a Fulbright postdoctoral scholarship in the United States (1973-1974). Over the years, he has spent more than five years as a visiting Professor at institutions across the United States, the United Kingdom, Denmark, and South Korea.

He investigated and published extensively on linear and rotary electric machine drives and magnetically levitated vehicles (MAGLEVs), focusing on their design and control for industrial applications, with his work appearing primarily in IEEE papers and books.

In recognition of his professional contribution, he received the 2015 Nikola Tesla IEEE Award and 2021 EPE Outstanding Achievement Award. He is a full member of both the Romanian Technical Sciences Academy (ASTR) and the Romanian Academy, and holds a Doctor Honoris Causa from Aalborg University, Denmark.

Prof. Boldea has given numerous keynote addresses at IEEE – sponsored international conferences and has delivered (as an IEEE-IAS Distinguished Lecturer since 2008) numerous intensive courses and lectures in the United States, Denmark, South Korea, Brazil and Italy, among other countries. He chaired and co-chaired the biannual IEEE Sponsored International Conference, OPTIM-ACEMP, for over 30 years. He has also held tech consulting contracts with international companies for decades, yearly and co-founded the company Bee-Speed (www.Bee-Speed.ro) in 1994, which is still continually active today, specializing in industrial digital electric automation in water integrated technologies.

He enjoys a rich family life and studies seminal books in philosophy, literature, economics, math and physics. He rides his bicycle to work daily, and his hobbies include gardening and tennis.