1st Edition

Inductors and Transformers for Power Electronics

    478 Pages 246 B/W Illustrations
    by CRC Press

    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.

    FUNDAMENTALS OF MAGNETIC THEORY
    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