This book presents a comprehensive introduction to design sensitivity
analysis theory as applied to electromagnetic systems. It treats the
subject in a unified manner, providing numerical methods and design
examples. The specific focus is on continuum design sensitivity
analysis, which offers significant advantages over discrete design
sensitivity methods. Continuum design sensitivity formulas are derived
from the material derivative in continuum mechanics and the variational
form of the governing equation. Continuum sensitivity analysis is
applied to Maxwell equations of electrostatic, magnetostatic and
eddy-current systems, and then the sensitivity formulas for each system
are derived in a closed form; an integration along the design interface.
The book also introduces the recent breakthrough of the topology
optimization method, which is accomplished by coupling the level set
method and continuum design sensitivity. This topology optimization
method enhances the possibility of the global minimum with minimised
computational time, and in addition the evolving shapes during the
iterative design process are easily captured in the level set equation.
Moreover, since the optimization algorithm is transformed into a
well-known transient analysis algorithm for differential equations, its
numerical implementation becomes very simple and convenient.
Despite the complex derivation processes and mathematical expressions,
the obtained sensitivity formulas are very straightforward for numerical
implementation. This book provides detailed explanation of the
background theory and the derivation process, which will help readers
understand the design method and will set the foundation for advanced
research in the future.