1st Edition
Inductors and Transformers for Power Electronics
Although they are some of the main components in the design of power electronic converters, the design of inductors and transformers is often still a trial-and-error process due to a long working-in time for these components. Inductors and Transformers for Power Electronics takes the guesswork out of the design and testing of these systems and provides a broad overview of all aspects of design.
Inductors and Transformers for Power Electronics uses classical methods and numerical tools such as the finite element method to provide an overview of the basics and technological aspects of design. The authors present a fast approximation method useful in the early design as well as a more detailed analysis. They address design aspects such as the magnetic core and winding, eddy currents, insulation, thermal design, parasitic effects, and measurements. The text contains suggestions for improving designs in specific cases, models of thermal behavior with various levels of complexity, and several loss and thermal measurement techniques.
This book offers in a single reference a concise representation of the large body of literature on the subject and supplies tools that designers desperately need to improve the accuracy and performance of their designs by eliminating trial-and-error.
Basic Laws of Magnetic Theory
Magnetic Materials
Magnetic Circuits
References
FAST DESIGN APPROACH INCLUDING EDDY CURRENT LOSSES
Fast Design Approach
Examples
Conclusions
Appendix 2.A.1: Core Size Scale Law for Ferrites in Non-Saturated Thermal Limited Design
Appendix 2.A.2: Eddy Current Losses for Wide Frequency
Appendix 2.A.3: MathCAD Example Files
References
SOFT MAGNETIC MATERIALS
Magnetic Core Materials
Comparison and Applications of the Core Materials in Power Electronics
Losses in Soft Magnetic Materials
Ferrite Core Losses with Non-Sinusoidal Voltage Waveforms
Wide Frequency Model of Magnetic Sheets Including Hysteresis Effects
Appendix 3.A: Power and Impedance of Magnetic Sheets
References
COIL WINDING AND ELECTRICAL INSULATION
Filling Factor
Wire Length
Physical Aspects of Breakdown
Insulation Requirements and Standards
Thermal Requirements and Standards
Magnetic Component Manufacturing Sheet
References
EDDY CURRENTS IN CONDUCTORS
Introduction
Basic Approximations
Losses in Rectangular Conductors
Quadrature of the Circle Method for Round Conductors
Losses of a Current Carrying Round Conductor in 2-D Approach
Losses of a Round Conductor in a Uniform Transverse AC Field
Low Frequency 2-D Approximation Method for Round Conductors
Wide Frequency Method for Calculating Eddy Current Losses in Windings
Losses in Foil Windings
Losses in Planar Windings
Appendix 5.A.1: Eddy Current 1-D Model for Rectangular Conductors
Appendix 5.A.2: Low Frequency 2-D Models for Eddy Current Losses in Round Wires
Appendix 5.A.3: Field Factor For Inductors
References
THERMAL ASPECTS
Fast Thermal Design Approach (Level 0 Thermal Design)
Single Thermal Resistance Design Approach (Level 1 Thermal Design)
Classic Heat Transfer Mechanisms
Thermal Design Utilizing a Resistance Network
Contribution to Heat Transfer Theory of Magnetic Components
Transient Heat Transfer
Summary
Appendix 6.A: Accurate Natural Convection Modeling for Magnetic Components
References
PARASITIC CAPACITANCES IN MAGNETIC COMPONENTS
Capacitance Between Windings: Inter Capacitance
Self-Capacitance of a Winding: Intra Capacitance
Capacitance Between the Windings and the Magnetic Material
Practical Approaches for Decreasing the Effects of Parasitic Capacitances
References
INDUCTOR DESIGN
Air Coils and Related Shapes
Inductor Shapes
Typical Ferrite Inductor Shapes
Fringing in Wire-Wound Inductors with Magnetic Cores
Eddy Currents in Inductor Windings
Foil Wound Inductors
Inductor Types Depending on Application
Design Examples of Different Types of Inductors
Fringing Coefficients For Gapped-Wire-Wound Inductors
Analitical Modeling of Combined Litz Wire-Full Wire Inductors
References
TRANSFORMER DESIGN
Transformer Design in Power Electronics
Magnetizing Inductance
Leakage Inductance
Using Parallel Wires and Litz Wires
Interleaved Windings
Superimposing Frequency Components
Superimposing Modes
References
OPTIMAL COPPER/CORE LOSS RATIO IN MAGNETIC COMPONENTS
Simplified Approach
Loss Minimization in the General Case
Loss Minimization Without Eddy Current Losses
Loss Minimization Including Low-Frequency Eddy Current Losses
Summary
Examples
References
MEASUREMENTS
Introduction
Temperature Measurements
Power Losses Measurements
Measurement of Inductances
Core Loss Measurements
Measurement of Parasitic Capacitances
Combined Measuring Instruments
References
APPENDIX A: RMS VALUES OF WAVEFORMS
Definitions
RMS Values of Some Basic Waveforms
RMS Values of Common Waveforms
APPENDIX B: MAGNETIC CORE DATA
ETD Core Data (Economic Transformer Design Core)
EE Core Data
Planar EE Core Data
ER Core Data
UU Core Data
Ring Core Data (Toroid Core)
P Core Data (Pot Core)
PQ Core Data
RM Core Data
APPENDIX C: COPPER WIRES DATA
Round Wire Data
American Wire Gauge Data
Litz Wire Data
APPENDIX D: MATHEMATICAL FUNCTIONS
References
INDEX
Biography
Alex P. M. Van den Bossche received the M.S. and the Ph.D. degrees from the University of Ghent, Belgium in 1980 and 1990 respectively. He has worked there at the Electrical Energy Laboratory Department, EESA. He has been engaged in research and published articles in the field of electrical drives and power electronics concerning various converter types, drives and various aspects of magnetic components and materials. His interests are also in renewable energy conversion. Since 1993, he has been a full professor at the same university. He is a senior member of the IEEE (M’99S’03).
Vencislav V. Valchev received the M.Sc. and Ph.D. degrees in electrical engineering from the Technical University of Varna, Bulgaria in 1987 and 2000, respectively. Since 1988 he has been with the Department of Electronics, Technical University of Varna, where he has been a lecturer. His research interests include power electronics, soft switching converters, resonant converters, and magnetic components for power electronics, renewable energy conversion.
Dr. Valchev had a cumulated common research period of about four years in the Electric Energy Laboratory research group in Ghent University, Belgium.
"This is a design manual for high-frequency transformers, especially for switching power supplies, interesting for: electronics design engineers, technicians, professors, and for technical libraries. …We warmly recommend to all specialists this clear, complete, up-to-date book."
—IEEE Power Electronics Newsletter"This book has enough depth and coverage of topics not found elsewhere that I am thankful to have a copy. Anyone who is serious about magnetics should invest in one. ... To their credit, the authors use SI (metric) units—no Oersted and Gauss. The illustrations are well-designed, well-drawn and informative, and references are given at the end of the chapters. No problem sets appear; this is not a textbook but a resource for engineers—a resource worth having for power-electronics design efforts."
—Dennis Feucht, from How2Power Today, July 2015