The Principles of Electronic and Electromechanic Power Conversion: A Systems Approach

A top–down approach that enables readers to master and apply core principles Using an innovative top–down approach, this text makes it possible for readers to master and apply the principles of contemporary power electronics and electromechanic power conversion, exploring both systems and individual components. First, the text introduces the role and system context of power conversion functions. Then the authors examine the building blocks of power conversion systems, describing how the components exchange power. Lastly, readers learn the principles of static and electromechanic power conversion. The Principles of Electronic and Electromechanic Power Conversion opens with a chapter that introduces core concepts in electrical systems and power conversion, followed by a chapter dedicated to electrical power sources and energy storage. Next, the book covers: Power, reactive power, and power factor Magnetically coupled networks Dynamics of rotational systems Power electronic converters DC machines AC machines The text offers readers a concise treatise on the basic concepts of magnetic circuits. Its simple approach to machines makes the principles of field–oriented control and space vector theory highly accessible. In order to help readers fully grasp power electronics, the authors focus on topologies that use a series transistor and diode combination connected to a DC source, a standard building block of todays power conversion systems. Problem sets at the end of each chapter enable readers to fully master each topic as they progress through the text. In summary, The Principles of Electronic and Electromechanic Power Conversion provides the most up–to–date, relevant tools needed by todays power engineers, making it an ideal undergraduate textbook as well as a self–study guide for practicing engineers.

PREFACE xi 1 INTRODUCTION TO ELECTRICAL SYSTEMS AND POWER CONVERSION 1 1.1 Electricity as an Energy Carrier / 1 1.2 Development of Electrical Energy Conversion Systems / 4 1.3 System Building Blocks / 6 1.4 Guide to the Book / 7 1.4.1 Generation, Storage and Consumption of Electricity / 8 1.4.2 Power Transfer and Matching of Loads and Sources / 8 1.4.3 Electromechanics / 9 1.4.4 Power Electronics / 9 Problems / 9 2 ELECTRICAL POWER SOURCES AND ENERGY STORAGE 11 2.1 Introduction / 11 2.2 Primary Sources / 12 2.2.1 Centralised Sources / 12 2.2.2 Decentralised Sources / 17 2.3 Secondary Sources / 20 2.3.1 Basic Concepts / 20 2.3.2 Storage as Chemical Energy—Hydrogen / 23 2.3.3 Storage as Electrochemical Energy / 23 2.3.4 Storage as Electrical Energy / 25 2.3.5 Storage as Mechanical Energy / 26 2.4 Highlights / 29 Problems / 30 3 POWER, REACTIVE POWER AND POWER FACTOR 35 3.1 Introduction / 35 3.2 Power in DC Circuits / 36 3.3 Power in Resistive AC Circuits / 38 3.4 Effective or rms Values / 39 3.5 Phasor Representation / 41 3.6 Power in AC Circuits / 45 3.6.1 Power in a Capacitive Circuit / 46 3.7 Apparent Power, Real Power and Power Factor / 49 3.8 Complex Power / 50 3.9 Electrical Energy Cost and Power Factor Correction / 52 3.10 Fourier Series / 56 3.11 Harmonics in Power Systems / 60 3.12 Power and Non–Sinusoidal Waveforms / 61 3.13 Effective or rms Value of Non–Sinusoidal Waveforms / 65 3.14 Power Factor of Non–Sinusoidal Waveforms / 66 3.15 Harmonics in Power Systems / 70 3.16 Three–Phase Systems / 73 3.17 Harmonics in Balanced Three–Phase Systems / 75 3.18 Highlights / 77 Problems / 80 Further Reading / 82 4 MAGNETICALLY COUPLED NETWORKS 85 4.1 Introduction / 85 4.2 Basic Concepts / 85 4.2.1 Ampère’s Circuital Law / 86 4.2.2 Faraday’s Induction Law / 87 4.2.3 Relationship between Magnetic Flux and Magnetic Field Strength / 89 4.2.4 Inductance / 93 4.2.5 Basic Magnetic Circuits / 95 4.2.6 Magnetic Circuit with an Air Gap / 99 4.3 Mutual Inductance / 101 4.3.1 Simple Air–Core Transformer / 103 4.3.2 Leakage Flux and the Transformer Core / 104 4.4 Ideal Transformer / 112 4.4.1 Referral of an Impedance / 113 4.4.2 Leakage and Magnetising Inductances / 114 4.5 Highlights / 118 Problems / 120 Further Reading / 121 5 DYNAMICS OF ROTATIONAL SYSTEMS 123 5.1 Introduction / 123 5.2 Preliminaries / 124 5.3 Rotational Dynamics / 127 5.3.1 Torque / 127 5.3.2 Angular Displacement, Speed and Acceleration / 128 5.3.3 Equations of Rotational Motion / 129 5.3.4 Moment of Inertia / 129 5.3.5 Rotating System / 130 5.4 Coupling Mechanisms / 133 5.4.1 Belt and Pulley / 134 5.4.2 Gears / 136 5.5 Highlights / 138 Problems / 140 Further Reading / 140 6 POWER ELECTRONIC CONVERTERS 141 6.1 Introduction / 141 6.2 Linear Voltage Regulator / 142 6.3 Switched Approach / 145 6.4 Basic Assumptions / 150 6.4.1 Switching Components / 150 6.4.2 Linear Components / 150 6.5 Buck Converter / 152 6.5.1 State I / 153 6.5.2 State II / 154 6.5.3 Combining the Two States / 154 6.5.4 Simplified Analysis Approach / 155 6.5.5 What if vc(t) ≠ Vc? / 157 6.6 Discontinious Conduction Mode / 162 6.6.1 Boundary between CCM and DCM / 162 6.6.2 Relationship between Vs and Vc in DCM / 164 6.7 Other Basic Converter Structures / 169 6.7.1 Boost Converter / 169 6.7.2 Buck–Boost Converter / 171 6.8 DC–DC Converters with Isolation / 172 6.8.1 Coupled Inductor Isolation: Flyback / 173 6.8.2 Transformer Isolation: Half–bridge / 178 6.8.3 Transformer Isolation: Full–bridge / 182 6.9 Highlights / 187 Problems / 189 Further Reading / 193 7 SIMPLE ELECTRICAL MACHINES 195 7.1 Introduction / 195 7.2 Motional Voltage and Electromagnetic Force / 196 7.2.1 Conductor Moving in a Uniform Magnetic Field / 196 7.2.2 Current–Carrying Conductor in a Uniform Magnetic Field / 201 7.2.3 Right–Hand Rule / 204 7.3 Simple Linear DC Machine / 204 7.3.1 Starting of the Linear DC Motor / 206 7.3.2 Linear DC Machine Operating as a Motor / 207 7.3.3 Linear DC Machine Operating as a Generator / 208 7.3.4 Electrical Equivalent Circuit of the Linear DC Machine / 209 7.3.5 Mechanical Equivalent Circuit of the Linear DC Machine / 211 7.3.6 A Practical Example: The Railgun / 211 7.4 Basic Operation of the DC Machine / 214 7.4.1 Induced Voltage / 214 7.4.2 Mechanical Voltage Rectification / 217 7.4.3 Force and Torque / 219 7.4.4 Power Balance between Mechanical and Electrical Power / 221 7.4.5 The benefit of a Uniform Air Gap / 223 7.5 Practical DC Machine Construction / 224 7.5.1 Induced Voltage in a Real DC Machine / 225 7.5.2 Torque Produced in a Real DC Machine / 227 7.6 Practical DC Machine Configurations / 231 7.6.1 Permanent Magnet DC Machine / 234 7.6.2 Field Winding DC Machines / 240 7.6.3 Losses / 244 7.7 DC Machine as a Component in a System / 246 7.8 Highlights / 248 Problems / 250 Further Reading / 252 8 AC MACHINES 253 8.1 Introduction / 253 8.2 Three–Phase AC Electrical Port / 253 8.3 AC Machine Stator / 256 8.3.1 Rotating Magnetic Field / 257 8.3.2 Reversing the Direction of Rotation / 260 8.3.3 Increasing the Number of Poles / 261 8.3.4 Flux Created in the Air Gap / 262 8.3.5 Induced Voltage in Three–Phase Stator Windings / 266 8.3.6 Increasing the Number of Poles / 268 8.3.7 Changing the Magnitude of the Induced Voltage / 269 8.4 Synchronous Machine / 271 8.4.1 The Equivalent Circuit / 273 8.4.2 Phasor Diagram / 275 8.4.3 Power Angle Characteristic Equation / 276 8.4.4 Controlling the Power Factor / 278 8.5 Induction Machine / 281 8.5.1 Induced Currents in the Induction Machine Rotor / 281 8.5.2 Development of an Equivalent Circuit / 287 8.5.3 Measurement of the Induction Machine Parameters / 291 8.5.4 Performance Calculations / 293 8.5.5 Induction Motor as a Component in a System / 297 8.6 Highlights / 299 Problems / 302 Further Reading / 304 INDEX 305

BRAHAM FERREIRA, PhD, is Professor in the Department of Electrical Sustainable Energy at Delft University of Technology, The Netherlands. WIM van der MERWE, PhD, is with ABB Corporate Research in Baden, Switzerland.