Power
Electronics
Devices, Circuits and Industrial
Applications Download PDF
Power Electronics Devices, Circuits and Industrial Applications PDF
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About Of The Book :
Power electronics is a branch of engineering that combines the fields of electrical power, electronics, and control. It started with the introduction of the mercury arc rectifier in 1900. The grid-controlled vacuum tube rectifier, ignition, and thyratron followed later. These found extensive application in industrial power control till 1950. In the meanwhile, the invention of the transistor—a semiconductor device— in 1948 marked a revolution in the field of electronics. It also paved the way for the introduction of the silicon-controlled rectifier (SCR), which was announced in 1957 by the General Electric Company. In due course, it has come to be named the ‘thyristor’. There is one important difference between the earlier electronic tubes and their semiconductor successors. On the low-current side, the transistor is a base current-controlled device whereas its predecessor, the vacuum tube, is a grid voltage-controlled device. Similarly, the thyristor, which is designed to carry high currents, is a gate current-controlled device; it has succeeded the thyratron, which is a grid voltage-controlled gas tube. After the inception of the thyristor, which is a p-n-p-n device, many other devices of its family came into existence. These include the DIAC, TRIAC, gate turn-off thyristor (GTO), and the MOS-controlled thyristor (MCT) among others. Subsequently, devices such as the power bipolar junction transistor (BJT), metal oxide semiconductor field effect transistor (MOSFET), and the IGBT have evolved as alternative power electronic devices, each of them being superior to the thyristor in one or more ways.
Contents Of The Book :
1. Thyristor Physics 1
1.1 Introduction 1
1.2 Behaviour of Semiconductor Devices under Biased Conditions 3
1.2.1 Behaviour of a Thyristor under Biased Conditions 6
1.2.2 Gate Firing of the Thyristor 9
1.2.3 Two‐Transistor Analogy of the Thyristor 11
1.3 Methods for Triggering 12
1.3.1 Thermal Triggering 12
1.3.2 Triggering due to Light Radiation 12
1.3.3 Gate Triggering 12
1.3.4 Effect of Load Parameters on Current Rise 16
1.3.5 dv/dt Triggering 16
1.3.6 Reverse Characteristic 18
1.4 Gate Turn‐on Methods 19
1.4.1 DC Triggering 20
1.4.2 AC Triggering 21
1.4.3 Unijunction Transistor Trigger Pulse Generator 28
1.5 Thyristor Turn‐off 36
1.5.1 Current Reduction 38
1.5.2 AC Line Commutation 39
1.5.3 Forced Commutation Circuits 39
1.6 Ratings of a Thyristor 48
1.6.1 Voltage Ratings 48
1.6.2 Current Ratings 49
1.6.3 Average Forward Current (IF (av) or IT ) 50
1.6.4 RMS Current Rating (ITR or IRMS) 54
1.6.5 Peak Repetitive Forward Current Rating (ITRM) 54
1.6.6 Surge Current Rating (ITSM or IFM) 55
t Rating 55
1.6.8 Other Ratings 55
1.7 Protection of Thyristors 55
1.7.1 Protection against Voltage Surges 56
1.7.2 Protection against Direct Overcurrents 61
1.7.3 Protection against Alternating Overcurrents 63
1.7.4 Gate Protection Circuits 64
Table of Contents
1.8 Other Members of the Thyristor Family 64
1.8.1 DIAC 65
1.8.2 TRIAC 66
1.8.3 Inverter Grade Thyristor 69
1.8.4 Gate Turn‐off Thyristor 69
1.8.5 Programmable Unijunction Transistor 73
1.8.6 Reverse Conducting Thyristor 76
1.8.7 Static Induction Thyristor 76
1.8.8 Light‐Activated SCR 76
1.8.9 MOS‐Controlled Thyristor 77
1.9 Other Power Electronic Devices 79
1.9.1 The Power Transistor 79
1.9.2 Power MOSFET 85
1.9.3 Insulated Gate Bipolar Transistor 89
1.10 Applications 90
Summary 91
Worked Examples 92
Exercises 106
2. Controlled Rectifiers 122
2.1 Introduction 122
2.2 Single‐Phase Rectifiers 124
2.2.1 Single‐Phase, Full‐Wave Circuit with Centre‐Tapped Secondary 125
2.2.2 Single‐Phase, Full‐Wave Bridge Rectifiers 127
2.3 Three‐Phase Rectifiers 134
2.3.1 Three‐Phase, Half‐Wave Controlled Rectifier 135
2.3.2 Three‐Phase, Full‐Wave Rectifiers 137
2.4 Voltage and Current Expressions for an n‐Phase Controlled Rectifier 145
2.4.1 n‐Phase Controlled Rectifier Feeding a Purely Resistive Load 145
2.4.2 n‐Phase Rectifier Feeding a Resistive Load in Series with a Battery of
Voltage Eb 147
2.4.3 n‐Phase Rectifier Feeding an Inductive Load 150
2.4.4 n‐Phase Rectifier Feeding an Inductive Load in Series with a Battery of
Voltage Eb 154
2.4.5 General Remarks Regarding n‐Phase Rectifiers 158
2.5 Inverting Mode of a Converter 159
2.5.1 Extinction Angle and its Significance 162
2.6 Ripple Factor 165
2.6.1 α ≤ sin‐1 (Vα/Vm) ‐ (π/2 ‐ π/n) 165
2.6.2 α> sin‐1 (Vα/Vm) ‐ (π/2 ‐ π/n) 168
2.7 Transformer Leakage Reactance and its Effects on Converter Performance 169
2.7.1 Effect of Leakage Reactance with α= 0 170
2.7.2 Effect of Leakage Reactance with α > 0 173
2.8 Rectifier Efficiency and Derating Factor of Rectifier Transformers 175
2.8.1 General Principles 176
2.8.2 Expressions for Rectifier Efficiency and Derating Factor 184
2.8.3 Summary of the Expressions for Rectifier Efficiency and Derating Factor 199
2.9 Input Power Factor 200
2.9.1 n‐Phase, Full‐Wave Fully Controlled Rectifier 201
2.9.2 Three‐Phase, Half‐Wave Controlled Rectifier 202
2.9.3 Three‐Phase, Half‐Wave Controlled Rectifier Fed by a Star/Zigzag
Transformer 202
2.9.4 Six‐Phase, Half‐Wave Rectifier Fed by a Star/Interstar Transformer 204
2.9.5 Six‐Phase, Half‐Wave Rectifier Fed by a Delta/Interstar Transformer 205
2.10 Dual Converters 206
2.10.1 Non‐Simultaneous Control 206
2.10.2 Simultaneous Control 208
2.10.3 Circulating Current 208
2.11 Hoist Operation 211
2.12 Braking of DC Motors 214
2.12.1 Dynamic Braking 214
2.12.2 Plugging 215
2.12.3 Regenerative Braking 216
2.13 Power Factor Improvement 218
2.13.1 Extinction Angle Control 219
2.13.2 Symmetrical Pulse Width Modulation 222
2.13.3 Selective Harmonic Elimination Using PWM 224
2.13.4 Sinusoidal PWM 227
2.13.5 Sequence Control of Rectifiers 229
Summary 235
Worked Examples 236
Exercises 254
3. DC Choppers 277
3.1 Introduction 277
3.1.1 Principle of a DC Chopper 278
3.2 Step‐down and Step‐up Choppers 279
3.2.1 Step‐down Chopper 279
3.2.2 Analysis with DC Motor Load 284
3.2.3 Step‐up Chopper 286
3.3 Choppers Based on the Quadrants of Operation 289
3.3.1 Second‐Quadrant Chopper 290
3.3.2 Two‐Quadrant Chopper 293
3.3.3 Four‐Quadrant Chopper 300
3.4 Speed Control of a Chopper‐Controlled DC Series Motor 307
3.5 Commutation Circuits 309
3.5.1 Modified Parallel Resonant Turn‐off Circuit 309
3.5.2 Morgan Chopper 313
3.5.3 Jones Chopper 316
3.5.4 A Special Current‐Commutated Chopper 318
3.5.5 Load Commutated Chopper 321
3.5.6 Voltage Commutated Chopper 325
3.6 Applications 327
3.7 Advantages and Drawbacks of DC Choppers 328
Summary 328
Worked Examples 329
Exercises 340
4. AC Line Voltage Control 349
4.1 Introduction 349
4.2 Methods for AC Voltage Variation 351
4.2.1 AC Voltage Variation by a Smoothly Varying Transformer 352
4.2.2 On‐off Control 352
4.2.3 Time‐Ratio Control 352
4.2.4 Switching the Supply Once in a Half‐Cycle 352
4.2.5 Periodically Switching the Supply Several Times in a Half‐Cycle 354
4.3 Single‐Phase AC Choppers 354
4.3.1 A Single‐Phase Chopper with a Resistive Load 354
4.3.2 A Single‐Phase Chopper with an Inductive Load 357
4.4 Three‐Phase AC Choppers 360
4.4.1 Chopper Category A 360
4.4.2 Chopper Category B 364
4.4.3 Chopper Category C 370
4.4.4 Chopper Category D 376
4.4.5 A Comparative Study of Three‐Phase Choppers 379
4.5 Single‐Phase AC Choppers Used as Sequence Controllers 380
4.5.1 Single‐Phase Transformer Tap‐Changer 381
4.6 Application of AC Controllers to AC Drives 386
Summary 391
Worked Examples 391
Exercises 406
5. Inverters
5.1 Introduction 414
5.2 Classification of Inverters 415
5.3 Single‐Phase, Parallel Capacitor Inverter 416
5.3.1 Analysis 420
5.3.2 Design of Commutating Elements 421
5.4 Voltage Source Inverters 425
5.4.1 Three‐Phase Bridge or Six‐Step Inverter 428
5.4.2 Single‐Phase McMurray Bridge Inverter 432
5.4.3 Three‐Phase McMurray Bridge Inverter 438
5.4.4 Single‐Phase McMurray‐Bedford Inverter 438
5.4.5 Analysis of the Single‐Phase McMurray‐Bedford Inverter 450
5.4.6 Three‐Phase McMurray‐Bedford Inverter 456
5.4.7 Three‐Phase 120°‐Mode VSI 457
5.4.8 Three‐Phase Input Circuit Commutated Inverter 458
5.5 Pulse Width Modulated VSIs 464
5.5.1 Single Pulse Width Modulated Inverters 464
5.5.2 Multiple Pulse Width Modulated Inverters 467
5.5.3 Sinusoidal PWM (SPWM) 469
5.5.4 Features of Output with PWM 470
5.5.5 Harmonics in Three‐Phase PWM Inverters 471
5.5.6 Advantages and Disadvantages of PWM Inverters 473
5.5.7 Constant Voltage‐to‐Frequency Operation of PWM Inverters 474
5.5.8 Reduction of Harmonics by the PWM Technique 474
5.6 Some Important Aspects of VSIs 476
5.6.1 Voltage Control of VSIs 476
5.6.2 Braking of VSI‐Based Drives 478
5.7 Current Source Inverters 480
5.7.1 Single‐Phase Current Source Inverter 481
5.7.2 Three‐Phase Bridge Type of Current Source Inverter 483
5.7.3 Regenerative Braking of CSI Drives 488
5.8 The Load Commutated Inverter 490
5.8.1 Line Commutated Converter 490
5.8.2 Bridge Inverter 490
5.8.3 Other Features of the LCI 495
5.8.4 Merits and Demerits of LCI 495
5.8.5 Applications of LCI 496
Summary 496
Worked Examples 497
Exercises 507
414
6. Cycloconverters 516
6.1 Introduction 516
6.2 Principle of the Cycloconverter 519
6.3 Non‐Simultaneous Control 520
6.4 Simultaneous Control 524
6.4.1 Inverse Cosine Firing 526
6.4.2 Firing Scheme for a Three‐Phase Dual Converter 528
6.4.3 Firing Scheme for a Single‐Phase, Line Commutated Cycloconverter 529
6.4.4 Four‐Quadrant Operation under Reactive Load Conditions 532
6.4.5 Circulating Currents in a Simultaneously Controlled Single‐Phase
Cycloconverter 533
6.5 Circuit Analysis 535
6.5.1 Output Voltage 535
6.5.2 Input Displacement Factor 536
6.5.3 Fundamental RMS Current 537
6.5.4 Transformer Rating 539
6.5.5 Current Ratings 539
6.5.6 Peak Reverse‐ and Forward Blocking Voltage Ratings 540
6.6 Three‐Phase Cycloconverters 542
6.7 Frequency and Voltage Control 544
6.8 Load Commutated and Forced‐Commutated Cycloconverters 546
6.9 Cycloconverter versus Six‐Step VSI 547
Summary 548
Worked Examples 549
Exercises 558
7. DC Drives 565
7.1 Introduction 565
7.2 Steady‐State Relationships of a Separately Excited DC Motor 566
7.3 Speed Control of a Separately Excited DC Motor 568
7.3.1 Armature Control Method 568
7.3.2 Field Control Method 570
7.3.3 Combined Armature and Field Control Method 571
7.4 Single‐Phase Converter Drives 572
7.5 Three‐Phase Converter Drives 574
7.5.1 Discontinuous Conduction 574
7.5.2 Continuous Conduction 576
7.6 Dynamic Behaviour of a Separately Excited DC Motor Fed by Rectifiers 577
7.6.1 Speed Control Using Armature Voltage Variation 577
7.6.2 Speed Control Loop Incorporating Field Voltage Variation 580
7.6.3 Closed‐Loop Current Control 581
7.6.4 Armature Control with an Inner Current Loop 582
7.6.5 A Comprehensive Control Scheme for Wide‐Range Speed Control 583
7.6.6 Closed‐Loop Drive with Four‐Quadrant Operation 584
7.6.7 Speed Control of a Rectifier Controlled DC Series Motor 587
7.7 Chopper‐Based DC Drives 589
7.7.1 Analysis of a Chopper‐Based Drive 590
7.7.2 Regenerative Braking of a Separately Excited DC Motor 591
7.7.3 Regenerative Braking of a DC Series Motor 595
Summary 597
Worked Examples 597
Exercises 618
8. AC Drives 627
8.1 Introduction 627
8.2 Induction Motor Drives 628
8.2.1 Equivalent Circuit and Analytical Relationships 629
8.2.2 Circuit Analysis 631
8.2.3 Speed‐Torque Curves 632
8.2.4 Methods for Speed Control 635
8.2.5 Control Schemes for Speed Control of Induction Motors 648
8.3 Rotor‐Related Control Systems for a Wound Rotor Induction Motor 652
8.3.1 Rotor Resistance Control 653
8.3.2 Slip Energy Recovery Scheme 659
8.4 Synchronous Motors 669
8.4.1 Cylindrical Rotor Machine 669
8.4.2 Salient Pole Machine 674
8.4.3 Speed and Torque Control 676
8.4.4 Open‐ and Closed‐Loop Control Schemes 677
8.4.5 Applications of Synchronous Motor Drives 681
Summary 682
Worked Examples 683
Exercises 717
9. Brushless DC Motors 731
9.1 Introduction 731
9.2 Sinusoidal and Trapezoidal Brushless DC Motors 732
9.3 Electronic Commutator 733
9.3.1 Optical Sensors 738
9.4 Torque Production 738
9.4.1 The Sinusoidal‐Type Two‐Phase, Brushless DC Motor 739
9.4.2 Three‐Phase, Half‐Wave, Brushless DC Motor 740
9.4.3 Three‐Phase, Full‐Wave, Brushless DC Motor 742
9.5 Control of Brushless DC Drives 744
9.5.1 A Typical Brushless DC Drive 745
9.6 Other Current Controllers 748
9.6.1 Ramp Comparison Current Control 748
9.6.2 Delta Current Control 748
9.6.3 Space Vector Current Control 749
9.7 Recent Trends 750
9.7.1 Materials Used for the Permanent Magnet 751
9.7.2 Alternative Methods for Rotor Position Sensing 751
9.7.3 Estimation of Winding Currents 751
9.8 Brushless DC Motors Compared with other Motors 751
9.8.1 Brushless DC Motor versus Brush DC Motor 751
9.8.2 Brushless DC Motor versus Induction Motor 752
9.8.3 Brushless DC Motor versus Brushless Synchronous Motor 753
Summary 753
Exercises 754
10. Control Circuits for Electronic Equipment 757
10.1 Introduction 757
10.2 Pulse Transformers 758
10.3 Opto‐Isolators 763
10.4 A Typical Scheme for Gate Firing 766
10.4.1 Firing Pulse Requirements for Inductive Loads 766
10.5 Zero Crossing Detection 770
10.5.1 Zero Voltage Detection 771
10.5.2 Zero Current Detection 774
10.6 Gate Firing Schemes for a Three‐Phase Bridge Converter 775
10.6.1 Ramp‐Comparator Method 775
10.6.2 Digital Firing Scheme 777
10.7 Gate Drive Circuits 779
10.7.1 Pulse Amplifier Circuit for Thyristors 779
10.7.2 Drive Circuit for Power Transistors 780
10.7.3 Drive Circuit for GTOs 782
10.7.4 Drive Circuit for MOSFETs 784
10.8 Transformer‐Isolated Circuits for Driving MOSFETs and IGBTs 785
10.8.1 Multipurpose Use of the Isolating Transformer 785
10.8.2 A Circuit with Smooth Duty Ratio Transition 787
Summary 787
Exercises 788
11. Industrial Applications 795
11.1 Introduction 795
11.2 Uninterruptible Power Supplies 795
11.2.1 Batteries 796
11.2.2 Inverters 797
11.2.3 Rectifiers 798
11.3 High‐Voltage DC Transmission 799
11.3.1 Twelve‐Pulse Line Frequency Converters 801
11.3.2 Reactive Power Drawn by Converters in the Rectifier Mode of Operation 804
11.3.3 Control of HVDC Converters 806
11.3.4 DC Circuit‐Breakers 808
11.3.5 Advantages of HVDC Transmission 808
11.4 Induction Heating 809
11.4.1 Principle of Induction Heating 809
11.4.2 Voltage Source versus Current Source Inverters 810
11.4.3 Need for a Current Source Inverter Established 812
11.4.4 A Practical Circuit for Induction Heating 813
11.4.5 Choice of Frequency 814
11.5 Welding 815
11.5.1 Resistance Welding 815
11.5.2 Arc Welding 815
11.6 Static VAR Control 817
11.6.1 Thyristor Controlled Inductors 818
11.6.2 Practical Realization of TCI 821
11.6.3 Control of Bus Voltage Using TCI 822
11.6.4 Thyristor Switched Capacitors 824
11.7 Desirable Features of DC Power Supplies 827
11.7.1 Linear Power Supplies 827
11.7.2 Comparison of Linear and Switch Mode Power Supplies 828
11.7.3 Block Diagram of a Switching Regulator 828
11.7.4 Isolation Transformer 829
11.7.5 Buck Boost Chopper 831
11.7.6 Principle of the Flyback Chopper 833
11.7.7 A Practical Flyback Chopper Circuit 838
11.7.8 A Typical SMPS Using a Flyback Chopper 839
11.7.9 Control of SMPSs 840
11.7.10 Merits and Demerits of the Flyback Chopper 843
Summary 844
Worked Examples 845
Exercises 848
12. Microprocessor Fundamentals 859
12.1 Introduction 859
12.2 Digital Systems 859
12.2.1 Latches, Tristate Logic, and Buffers 860
12.2.2 Flip‐Flops 865
12.2.3 Registers and Shift Registers 869
12.2.4 Decoders 870
12.2.5 Memories 871
12.2.6 Counters 873
12.3 Digital Arithmetic 874
12.3.1 Binary Addition 874
12.3.2 Octal and Hexadecimal Addition 875
12.3.3 Subtraction of Binary Numbers 876
12.3.4 2's Complement Subtraction 877
12.3.5 Arithmetic and Logic Unit 878
12.4 Microprocessor Structure and Programming 878
12.4.1 Salient Features of a Microcomputer/Microprocessor 879
12.4.2 Architecture of the 8085A Microprocessor 880
12.4.3 Assembly Language for 8085A 882
12.4.4 Writing Assembly Language Programs 886
12.4.5 Stack and Subroutines 891
12.5 Timing Waveforms 893
12.6 Interfacing the Microprocessor with Peripherals 894
12.6.1 Interfacing I/O Devices 895
12.6.2 I/O Ports 896
12.7 The 8086 Microprocessor 904
12.7.1 Bus Interface Unit 905
12.7.2 Execution Unit 907
12.7.3 Programming on the 8086 908
12.7.4 Structured Programming 912
12.7.5 Writing Machine Code for Instructions 913
12.7.6 Necessity of an Assembler 917
12.7.7 The 8086 Instruction Set 919
Summary 921
Exercises 922
13. Microcomputer Control of Industrial Equipment 929
13.1 Introduction 929
13.2 Closed‐Loop Control of DC Drives 930
13.3 A Microprocessor‐Based Induction Motor Drive 932
13.4 Pulse Width Modulation 936
13.5 Protection Including Fault‐Monitoring and Control 937
13.6 Advantages of Microcomputer‐Based Control 938
13.7 Limitations of Microcomputer‐Based Control 939
Summary 939
Exercises 939
14. Field Oriented Control of AC Motors 942
14.1 Introduction 942
14.1.1 Torque Production in Electrical Motors 943
14.1.2 Mechanical Analogies of Electrical Motors 946
14.1.3 Application of Field Oriented Control Principle to an Induction
Motor/Synchronous Motor 948
14.2 Mathematical Model of an Induction Motor 948
14.3 Implementation of Field Oriented Control for a VSI Controlled AC Motor 954
14.4 Position Control with a Voltage Source PWM Inverter 957
14.4.1 τr Identification 959
14.5 Speed Control of an Induction Motor Fed by a Current Source Inverter 959
14.5.1 Application of Field Oriented Control 960
14.5.2 Microprocessor‐Based Implementation 962
14.6 Some Special Aspects of Field Oriented Control 962
14.6.1 Direct and Indirect Field Oriented Control 963
14.6.2 Implementation Using Stator Currents 964
14.6.3 VSI‐Based versus CSI‐Based Drives 964
14.6.4 Problems Associated with Flux Acquisition 965
14.6.5 Field Oriented Control of a Synchronous Motor 966
Summary 966
Exercises 967
Appendix A: Fourier Series Expansion of Periodic Quantities 973
Appendix B: Analysis of Electric Circuits 976
Appendix C: Choppers for Switch Mode Power Supplies 985
Appendix D: Resonant Pulse Inverters 993
Appendix E: 8085/8080A Instruction Summary 1001
Appendix F: Commonly Used Functions 1003
Information Of The Book :
Title: Power Electronics Devices, Circuits and Industrial Applications PDF
Language: English.
Size: 8 Mb
Pages: 1017
Year : 2005
Format: PDF
Author: Moorthi & V. R