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Preface
waveform and THD of a DCM boost rectifier, and comparing the transfer functions and output imped-
ances of buck converters operating with current programmed control and with duty cycle control. The
major purpose of Appendix B is to supplement the text discussions, and to enable the reader to effec-
tively use averaged models and simulation tools in the design process. The role of simulation as a design
verification tool is emphasized. In our experience of teaching introductory and more advanced power
electronics courses, we have found that the use of simulation tools works best with students who have
mastered basic concepts and design-oriented analytical techniques, so that they are able to make correct
interpretations of simulation results and model limitations. This is why we do not emphasize simulation
in introductory chapters. Nevertheless, Appendix B is organized so that simulation examples can be
introduced together with coverage of the theoretical concepts of Chapters 3, 7, 9, 10, 11, 12, and 18.
Middlebrook’s Extra Element Theorem is presented in Appendix C, together with four tutorial
examples. This valuable design-oriented analytical tool allows one to examine effects of adding an extra
element to a linear system, without solving the modified system all over again. The theorem has many
practical applications in the design of electronic circuits, from solving circuits by inspection, to quickly
finding effects of unmodeled parasitic elements. In particular, in the Second Edition, Middlebrook’s
Extr
a
Element Theorem is applied to the input filter design of Chapter 10, and to resonant inverter design
in Chapter 19.
In Chapter 7, we have revised the section on circuit averaging and averaged switch modeling.
The process of circuit averaging and deriving averaged switch models has been explained to allow read-
ers not only to use the basic models, but also to construct averaged models for other applications of inter-
est. Examples of extensions of the averaged switch modeling approach include modeling of switch
conduction and switching losses. Related to the revision of Chapter 7, in Appendix B we have included
new material on simulation of converters based on the averaged switch modeling approach.
Chapter 8 contains a new substantial introduction that explains the engineering design process
and the need for design-oriented analysis. The discussions of design-oriented methods for construction
of frequency response have been revised and expanded. A new example has been added, involving
approximate analysis of a damped input filter.
Chapter 11 on dynamics of DCM (discontinuous conduction mode) converters, and Chapter 12
on current-mode control, have been thoroughly revised and updated. Chapter 11 includes a simplified
derivation of DCM averaged switch models, as well as an updated discussion of high-frequency DCM
dynamics. Chapter 12 includes a new, more straightforward explanation and discussion of current-mode
dynamics, as well as new complete results for transfer functions and model parameters of all basic con-
verters.
The chapters on magnetics design have been significantly revised and reorganized. Basic mag-
netics theory necessary for informed design of magnetic components in switching power converters is
presented in Chapter 13. The description of the proximity effect has been completely revised, to explain
this important but complex subject in a more intuitive manner. The design of magnetic components based
on the copper loss constraint is described in Chapter 14. A new step-by-step design procedure is given
for multiple-winding inductors, and practical design examples are included for the design of filter induc-
tors, coupled inductors and flyback transformers. The design of magnetic components (transformers and
ac inductors) based on copper and core loss considerations is described in Chapter 15.
To improve their logical flow, the chapters covering pulse-width modulated rectifiers have been
combined into a single Chapter 18, and have been completely reorganized. New sections on current con-
trol based on the critical conduction mode, as well as on operation of the CCM boost and DCM flyback
as PWM rectifiers, have been added.
Part V consists of Chapter 19 on resonant converters and Chapter 20 on soft-switching convert-
ers. The discussion of resonant inverter design, a topic of importance in the field of high-frequency elec-
tronic ballasts, has been expanded and explained in a more intuitive manner. A new resonant inverter
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