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Telecom Power Systems PDF

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Telecom Power Systems Telecom Power Systems Dorin O. Neacsu , MATLAB and Simulink are a trademark of The MathWorks, Inc. and are used with permission. The MathWorks does not warrant the accuracy of the text or exercises in this book. This book’s use or discussion of MATLAB and Simulink software or related products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular use of the MATLAB and Simulink software. CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2018 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper International Standard Book Number-13: 978-1-138-09930-2 (Hardback) This book contains information obtained from authentic and highly regarded sources. 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Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com Contents Preface ...................................................................................................................xiii Author ..................................................................................................................xvii 1. Power System Architecture for Telecommunications Applications ....1 1.1 Context ....................................................................................................1 1.2 Example of Architecture for a Telecommunications Application ......................................................................................4 1.2.1 Role of and Requirements for Rectifier .................................5 1.2.2 Role of and Requirements for High-Power Isolated Direct Current/Direct Current Converter ............................5 1.2.3 Role of and Requirements for Isolated Converter (‘Brick’ Converter) ....................................................................6 1.2.4 Role of and Requirements for Point-of-Load Direct Current/Direct Current Converters ......................................8 1.3 What Is Specific to Power Converters? Switched-Mode Operation..............................................................................................10 1.4 What Is Specific to Power Converters? Installed Power ................12 1.5 System Architecture Concepts ..........................................................12 1.6 Rack Usage within Data and Telecom Centres ...............................14 1.7 Considerations for Power Systems within a Data or Telecom Centre ....................................................................................................15 1.8 Lifetime and Reliability .....................................................................18 1.9 Special Design Requirements and Software-Intensive Control Systems ...................................................................................18 Summary .........................................................................................................20 References .......................................................................................................20 2. Power Semiconductor Devices ...................................................................23 2.1 Context ..................................................................................................23 2.2 Diodes ...................................................................................................23 2.3 Thyristors .............................................................................................26 2.4 The Ideal Switch ..................................................................................26 2.5 Switched-Mode Power Metal–Oxide–Semiconductor Field- Effect Transistor ..................................................................................28 2.6 Insulated Gate Bipolar Transistor .....................................................29 2.7 Switching of Power Semiconductor Devices ...................................30 2.8 Power Loss and Heat Removal ..........................................................32 2.9 Gate Driver Circuits ............................................................................37 2.10 Protection of Power Semiconductor Devices ..................................39 v vi Contents 2.11 Gate Turn-Off Devices ........................................................................41 2.12 Device Selection ..................................................................................42 Summary .........................................................................................................43 References .......................................................................................................44 3. Buck and Boost Converters .........................................................................45 3.1 The Role of Direct Current/Direct Current Power Converters ....45 3.2 Direct Conversion (without Galvanic Isolation) .............................45 3.3 Buck Converter ....................................................................................46 3.3.1 Example ...................................................................................47 3.4 Boost Converter ...................................................................................54 3.5 Other Topologies of Direct Current/Direct Current Converters .......................................................................................58 3.6 Multiphase Converters .......................................................................60 3.7 The Synchronous Converter ..............................................................62 3.8 Selection of Passive Components ......................................................63 3.8.1 Selection of the Buck Inductor .............................................64 3.9 Control Circuits for Buck/Boost Converters ...................................67 Summary .........................................................................................................69 References .......................................................................................................70 4. Point-of-Load Converters and Their Feedback Control Systems .......73 4.1 Context ..................................................................................................73 4.2 Implementation within Analogue-Mode Power Supply Circuits ....................................................................74 4.3 Design of Feedback Control Systems ...............................................77 4.3.1 Definitions...............................................................................77 4.3.2 Requirements for Feedback Control of a Power Supply ....80 4.3.3 Using Lead-Lag Compensators ............................................82 4.4 Case Studies: Feedback Control for Various Power Supplies .......86 4.4.1 Example 1 = Linear Circuitry, Follower (NPN Power Transistor with Common Collector) ....................................87 4.4.2 Example 2 = Low-Dropout Voltage Stabiliser with an Inverting Topology ...........................................................90 4.4.3 Example 3 = Switched-Mode Boost/Buck Converters .....94 4.5 Analogue-Mode Feedback Control Solutions .................................95 4.5.1 Type I Compensation ............................................................96 4.5.2 Type II Compensation ...........................................................98 4.5.3 Type III Compensation ..........................................................98 4.6 Design Process from Constraints to Component Selection ........101 4.6.1 Pole-Zero Empirical Selection Based on Converter Model .....................................................................................101 4.6.2 Venable K-Factor Method ....................................................102 4.6.3 MATLAB Analysis of Results ............................................108 4.6.4 The Problem of Conditionally Stable Systems .................112 Contents vii 4.7 On Usage of Conventional Proportional–Integral– Derivative Controllers ......................................................................113 4.8 Conversion of Analogue Control Law to Digital Solutions ........115 Summary .......................................................................................................119 References .....................................................................................................119 5. State-Space Control of DC/DC Converters ...........................................121 5.1 Modern versus Classical Control Methods ...................................121 5.2 State-Space Modelling ......................................................................122 5.3 Definition of Control Law with State-Space Method ...................130 5.4 Using Estimators ...............................................................................142 5.5 Change of Gains with Load and Dwell Time ...............................145 5.6 Practical Aspects: Implementation Problem .................................148 Summary .......................................................................................................149 References .....................................................................................................150 6. Isolated DC/DC Converters: Flyback, Forward and Push-Pull ........151 6.1 Role of Direct Current/Direct Current Converters with Isolation ..............................................................................................151 6.2 Physics of the Pulse Transformer....................................................152 6.3 Flyback Converter .............................................................................156 6.3.1 Operation ..............................................................................156 6.3.2 Control ...................................................................................160 6.3.3 Multioutput Flyback Converters........................................163 6.3.4 Protection ..............................................................................163 6.3.5 Two-Switch Flyback Converter ..........................................164 6.4 Forward Converter............................................................................165 6.4.1 Operation ..............................................................................165 6.4.2 Multioutput Forward Converter with Coupled Inductors ...............................................................................171 6.5 Forward-Flyback Converter .............................................................173 6.6 Push-Pull Converter .........................................................................176 6.7 The Need for a Closed-Loop Controller ........................................180 6.8 Feedback Control of Isolated Converters: Working with TL431 ......................................................................................181 Summary .......................................................................................................183 References .....................................................................................................184 7. Converters with Reduced Power Loss ....................................................185 7.1 Context ................................................................................................185 7.2 Resonant Converters .........................................................................187 7.2.1 Step-Down Conversion .......................................................187 7.2.2 Step-Up Conversion .............................................................193 7.3 Phase-Shift Converters .....................................................................196 7.3.1 Operation of the Phase-Shift Converter ...........................196 viii Contents 7.3.2 Zero-Voltage Transition .......................................................201 7.3.3 Example of Integrated Circuits for Phase-Shift Converter Control ................................................................208 7.3.4 Brick Converters Using Phase-Shift Converters .............211 7.4 LLC Converters..................................................................................211 7.4.1 Operation ..............................................................................211 7.4.1.1 Operation with Switching Frequency above the Resonance Frequency ........................214 7.4.1.2 Operation with Switching Frequency below the Resonance Frequency ........................216 7.5 Synchronous Rectification on Secondary Side .............................217 Summary .......................................................................................................218 References .....................................................................................................218 8. Power Management of Embedded Systems ..........................................221 8.1 Requirements for Digital Control ...................................................221 8.2 Power Control versus Digital Management of Power Supplies .........................................................................................221 8.3 Examples of Management Functions for Power Supplies ...........224 8.3.1 Dynamic Adjustment of the Voltage Applied onto the Intermediary Bus ...........................................................224 8.3.2 Continuous Adjustment of Voltage Control Law Gains .................................................................................224 8.3.3 Adjustment of the Output Voltage at Point-of-Load Converters .............................................................................225 8.3.4 Adaptive Control of Dead Time .........................................226 8.3.5 Selection of the Number of Branches within a Multiphase Converter..........................................................227 8.4 Connectivity.......................................................................................227 8.4.1 Inter-integrated Circuit Hardware ....................................228 8.4.2 Inter-integrated Circuit Protocol .......................................228 8.4.3 Inter-integrated Circuit Software Sequence.....................230 8.4.4 Examples of Integrated Circuits with Inter- integrated Circuit Interface ................................................231 8.5 Historical Perspective on System Management Bus ....................232 8.6 Introduction of Power Management Bus .......................................232 8.6.1 Hardware ..............................................................................232 8.6.2 Data Format and Telemetry ................................................234 8.6.3 Addressing ............................................................................236 8.6.4 Set of Commands .................................................................237 8.6.5 Voltage Setting......................................................................238 8.6.6 Fault Management ...............................................................239 8.6.7 Using Nonvolatile Memory within Integrated Circuits ....240 8.7 Methods for Power Savings in Computing Systems ....................241 8.7.1 Power Loss Components .....................................................241 Contents ix 8.7.2 Deployment of Dynamic Voltage and Frequency Scaling Methods ...................................................................243 8.7.3 Strategies Used with Dynamic Voltage and Frequency Scaling ................................................................244 8.7.4 Diminished Results for Dynamic Voltage and Frequency Scaling with Multicore Processors.................245 8.7.5 Strategies for Static Power Reduction ...............................247 Summary .......................................................................................................249 References .....................................................................................................249 9. Diode Rectifiers ...........................................................................................251 9.1 Power Rectifier Usage .......................................................................251 9.2 Operation of a Single-Diode Rectifier ............................................251 9.3 Operation of a Bridge Rectifier ........................................................255 9.4 Connection Inductance Influence on the Commutation Process ................................................................................................259 9.5 Rectifier Distortion on Grid Voltages .............................................260 9.6 Other Single-Phase Rectifiers: Alternating Current Doubler Rectifier ...............................................................................................263 9.7 Three-Phase Rectifiers ......................................................................263 9.7.1 Midpoint Rectifier ................................................................264 9.7.2 Three-Phase Bridge Rectifiers ............................................268 Summary .......................................................................................................273 References .....................................................................................................273 10. Power Factor Correction ............................................................................275 10.1 Harmonics and Power Factor ..........................................................275 10.1.1 Sinusoidal Measures ............................................................275 10.1.2 Nonsinusoidal Waveforms .................................................276 10.2 Power Factor Improvement ..............................................................278 10.3 Peak Current Control ........................................................................278 10.4 Hysteresis Control and Variable Pulse Frequency .......................284 10.5 Control with Current Compensation .............................................284 10.6 Assessment of Results ......................................................................286 10.6.1 Comparison between the Three Control Methods .........286 10.6.2 Control with Fixed Duty Cycle, Open Loop ....................288 10.6.3 Compensation Method with Second Harmonic Injection ..............................................................288 10.6.4 Discontinuous Conduction Mode versus Continuous Conduction Mode Power Factor Correction with Boundary Control ................................................................290 10.7 Three-Phase Circuit for Unity Power Factor .................................292 10.8 Power Factor Control ........................................................................294 Summary .......................................................................................................296 References .....................................................................................................297

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