POWER ELECTRONICS S.C. Tripathy Alpha Science International Ltd. Oxford, U.K.
Contents Preface vii 1. SEMICONDUCTOR DIODE THEORY 1.1 1.1 Introduction 1.1 1.2 Charge Densities in a Doped Semiconductor 1.1 1.3 Junction Diode 1.2 1.4 Methods of Making Junctions 1.3 1.5 General Purpose Power Diode 1.4 1.6 Potential Barrier at Thermal Equilibrium 1.4 1.7 Current Flow in Semi Conductor Diode 1.6 1.8 No Applied Bias (VP > OV) 1.6 1.9 Forward Bias Condition (VD > OV) 1.7 1.10 Reverse Bias Condition (VD < OV) 1.8 1.11 Zener Region 1.10 1.12 Silicon Versus Germanium 1.11 1.13 Temperature Effects 1.12 1.14 Resistance Levels 1.12 1.15 Diffusion Capacitance and Transition Capacitance 1.17 1.16 Simplified Equivalent Circuit 1.18 1.17 Zener Diode 1.18 1.18 Light Emitting Diode (LED) 1.20 References 1.21 2. POWER DIODES AND TRANSISTORS 2.1 2.1 Introduction 2.1 2.2 Power Diode Types 2.1 2.3 Reverse Recovery Characteristic of Power Diode 2.4 2.4 Bipolar Junction Transistor (BJT) 2.6 2.5 Power Transistor Structure 2.10 2.6 Terminal Connections 2.11 2.7 Light and Other Radiation 2.12 2.8 Principle of Bipolar Junction Transistor Operation 2.12 2.9 Transistor Amplifying Action 2.14 2.10 Steady-State Characteristics 2.16 2.11 BJT as a Switch 2.18 2.12 BJT Switching Performance 2.19 2.13 V-I Characterstic of Power Transistor 2.21 2.14 Switching Limits 2.22 References 2.23
X Contents DIODES RECTIFIERS 3.1 3.1 Introduction 3.1 3.2 Half-wave Rectifier Circuit 3.1 3.3 Resistive Load Circuit 3.3 3.4 RC Load Circuit 3.5 3.5 RL Load Circuit 3.6 3.6 Half-Wave Rectifier with RE Load 3.10 References 3.11 MOSFET AND IGBT 4.1 4.1 Introduction 4.1 4.2 Field Effect Transistor 4.1 4.3 Types of Field Effect Transistors 4.1 4.4 Depletion Type N-Channel MOSFET Structure 4.3 4.5 V-I Characteristics 4.5 4.6 Enhancement Type MOSFETS 4.7 4.7 JFET and Depletion MOSFET Small Signal Model 4.10 4.8 MOSFET Gate Protection 4.10 4.9 Enhancement MOSFET Bias Circuits 4.11 4.10 Power MOSFET 4.12 4.11 Comparison of Power MOSFET With BJT 4.13 4.12 Gate Drive Circuit For MOSFET 4.13 4.13 IGBT (Insulated-Gate-Bipolar-Transistor) 4.14 4.14 Basic Structure 4.15 References 4.16 PSPICE: SIMULATION SOFTWARE 5.1 5.1 Introduction 5.1 5.2 Circuit Description and Analysis 5.1 5.3 Nodes 5.2 5.4 Circuit Elements 5.3 5.5 Element Values 5.4 5.6 Format for Passive Elements 5.4 5.7 Element Models 5.5 5.8 Source 5.5 5.9 Analysis Type 5.10 Output Variables 5.6 5.11 PSPICE Output Commands 5.6 5.12 Format on Output Files 5.6 5.13 Loading on PC 5.6 5.14 Signal Approximation 5.6 5.15 Diode Model 5.8 References 5.10 5.5
Contents xi 6. THYRISTOR (SCR) 6.1 6.1 Introduction 6.1 6.2 Modes Of Operation 6.3 6.3 SCR V-I Characteristics 6.6 6.4 Two-Transistor Model of SCR 6.7 6.5 Transient Condition 6.8 6.6 SCR Ratings 6.9 6.7 Switching Characteristic of SCR During Turn-On 6.13 6.8 Method to Improve di/dt and dv/dt Ratings 6.17 6.9 Snubber Circuit 6.19 6.10 Electronic Crowbar Protection 6.23 6.11 Gate Protection 6.23 6.12 Heating and Cooling of SCR 6.24 References 6.25 7. THYRISTOR FAMILY, TIMING AND OP-AMP CIRCUITS 7.1 7.1 Introduction 7.1 7.2 Shockley Diode 7.1 7.3 Diac 7.2 7.4 Triac BI-Directional SCR 7.3 7.5 Light Activated Silicon Controlled Rectifier 7.6 7.6 Gate Turn off Thyristor 7.6 7.7 MOS Controlled Thyristor 7.8 7.8 FET Controlled Thyristor 7.9 7.9 Static Induction Thyristor 7.9 7.10 Reverse Conducting Thyristor (RCT) 7.10 7.11 Asymmetrical SCR (ASCR) 7.10 7.12 Emitter Turn-Off Thyristor (ETO) 7.11 7.13 Uni-Junction Transistor 7.12 7.14 Programmable UJT (PUT) 7.17 7.15 Silicon Controlled Switch 7.18 7.16 Silicon Unilateral Switch 7.19 7.17 Silicon Bilateral Switch 7.20 7.18 555 Timer 7.20 7.19 Operational Amplifier 7.22 7.20 Op-Amp Characteristics 7.23 7.21 Equivalent Circuit of Op-Amp 7.26 7.22 Inverting Amplifier 7.27 7.23 Logarithm and Exponential Amplifiers 7.30 References 7.31
Pulse) xii Contents 8. SERIES AND PARALLEL CONNECTION OF SCRs, THEIR GATE CHARACTERISTICS AND FIRING CIRCUITS 8.1 8.1 Introduction 8.1 8.2 Series Connection 8.1 8.3 Dynamic Equalizing Circuit 8.3 8.4 Parallel Connection of SCRs 8.7 8.5 Gate Characteristics of SCRs 8.10 8.6 Gate Circuit 8.16 8.7 SCR Firing (Triggering) Circuits 8.17 References 8.26 9. CONTROLLED RECTD7BERS 9.1 9.1 Introduction 9.1 9.2 Single Phase Half Wave Converter with R Load 9.2 9.3 Single Phase Half Wave Converter with RL Load 9.4 9.4 Mid-Point Full Wave Converter with RL Load 9.9 9.5 Single Phase Two Pulse Converter with Discontinuous Load Current 9.15 9.6 Dual Converter 9.16 9.7 Multiphase Converters 9.18 9.8 Three Phase Fully Controlled Converter with RLE-Load 9.27 9.9 Three Phase Semieonverter 9.30 9.10 Effect of Source Impedance on Converter Operation 9.33 References 9.35 10. SCR COMMUTATION CIRCUITS 10.1 10.1 Introduction 10.1 10.2 Class A Commutation (Load Commutation) 10.1 10.3 Class B Commutation (Resonant - 10.4 10.4 Class C Complementary Voltage Commutation 10.7 10.5 Class D Impulse Commutation 10.8 10.6 Class E External Pulse Commutation 10.10 10.7 Class F Line Commutation 10.11 10.8 Class G Current Commutation 10.11 References 10.12 11. AC VOLTAGE CONTROLLERS 11.1 11.1 Introduction 11.1 11.2 Phase-Angle Control 11.1 11.3 Single-Phase Half-Wave Voltage Controller 11.1 11.4 Single-Phase Full-Wave Voltage Controller with R Load 11.3 11.5 Harmonic Analysis 11.7 11.6 Single-phase Full-Wave Voltage Controller with RL Load 11.8 11.7 Integral Cycle Control 11.12 11.8 Sequence Control of AC Voltage Controller (Transformer Tap Changer) 11.16 11.9 Three Phase Full-Wave Regulator 11.17 References 11.21
Contents xiii 12. CYCLOCONVERTERS 12.1 12.1 Introduction 12.1 12.2 Basic Principle 12.1 12.3 Practical Cycloconverter Circuits 12.3 12.4 Step Up Cycloconverter (Single-Phase Mid Point Type) 12.4 12.5 Step-Down Cycloconverter (Single Phase): R Load 12.5 12.6 Step-Down Cycloconverter with RL Load 12.6 12.7 Waveform for 3-phase to Single-Phase Half-Wave Cycloconverter 12.9 12.8 Output Voltage (Three Phase to Single Phase Cycloconverter) 12.10 12.9 Non-Circulating Current Scheme 12.13 12.10 Bridge Type Cycloconverter 12.13 12.11 Load-Commutated Cycloconverter 12.14 12.12 Three-Phase to Three-Phase Converter 12.15 12.13 Firing Angle Control by Cosine Modulating Signal 12.16 References 12.17 13. D.C. CHOPPER 13.1 13.1 Introduction 13.1 13.2 Principle of Step Down Chopper Operation 13.1 13.3 Pulse Width Modulation (PWM) 13.3 13.4 Step Up Chopper 13.4 13.5 Step Down Chopper With RLE Load: (Transient Analysis) 13.7 13.6 Step-Up/Step-Down Chopper 13.11 13.7 Chopper Classification 13.12 13.8 SCR Chopper Commutation Circuits 13.16 13.9 Jones Chopper (Voltage Commutated Chopper) 13.17 13.10 Morgan Chopper (Current Commutated Chopper) 13.21 13.11 Load Commutated Chopper 13.24 References 13.27 14. INVERTERS 14.1 14.1 Introduction 14.1 14.2 Classification of Inverters 14.1 14.3 Classification of SCR Based Inverters 14.3 14.4 Single-Phase Half Bridge Voltage Source Inverters 14.4 14.5 Performance Indices of Square-Wave Inverters 14.11 14.6 Voltage Control of Single-Phase Inverter by PWM 14.18 14.7 Principle of Operation of Three-Phase Inverters 14.25 14.8 Comparison Between 120 and 180 Conduction Schemes 14.34 14.9 Modified McMurrary Inverter 14.35 14.10 Design of Commutation Circuit 14.40 14.11 Modified McMurray Full-Bridge Single-Phase Inverter 14.42 14.12 McMurrary Bedford Inverter 14.42 14.13 Modified McMurrary-Bedford Inverter 14.45
Off XIV Contents 14.14 Other Types of Inverters 14.48 14.15 Current Source Inverter (CSI) 14.54 14.16 Voltage and Frequency Control of Inverter 14.61 References 14.62 15. DC-DC SWITCH MODE REGULATORS, SM-POWER SUPPLIES, AND RESONANT PULSE CONVERTERS 15.1 15.1 Introduction 15.1 15.2 Buck Regulator (Step Down Regulator) 15.1 15.3 Boost Regulator 15.5 15.4 Buck-Boost Regulator 15.7 15.5 Cuk Regulator 15.9 15.6 Switch Mode Regulator with Isolation 15.11 15.7 Isolated SMPS (Switch Mode Power Supply) 15.11 15.8 Uninteruptible Power Supply - Line UPS 15.15 15.9 Resonant Pulse Converters 15.15 15.10 Zero-Voltage Switching Resonant Converter 15.22 References 15.26 16. SOLID-STATE MOTOR CONTROL AND ELECTRICAL DRIVES 16.1 16.1 Introduction 16.1 16.2 Application of Solid-State Controls 16.1 16.3 Introduction to Rectifier Circuits 16.5 16.4 DC Motor Drive Systems 16.11 16.5 Three Phase Full Converter Fed DC Drive 16.13 16.6 Three Phase Dual Converter DC Drive 16.15 16.7 Choppers 16.16 16.8 Power Electronic Control of AC Drive 16.22 16.9 Starting Methods of Induction Motor 16.25 16.10 Thyristorised Starting 16.26 16.11 Speed Control 16.29 16.12 Voltage Control by Power Electronic Method 16.29 16.13 Additional Methods of Speed Control for Induction Motors 16.31 16.14 Speed Control of Induction Motors Using 16.15 Static Rotor-Resistance Control 16.36 Inverters 16.32 16.16 Slip-Power Recovery Schemes 16.42 16.17 Synchronous Motor Drives 16.50 References 16.51 Appendix A: Probable Values of General Physical Constants Appendix B: Symbols of Power Semiconductor Devices B. 1 Appendix C: Multiple Choice Questions C. 1 A.l Index l.l