Preface of "Control and Dynamics in Power Systems and Microgrids" by L. Fan

The main part of the book was written in Spring 2016 when the author taught Power Systems II, a
graduate course at University of South Florida, Tampa Florida. The course was designed to focus on
control and dynamics of power systems. Bergen and Vittal's book, Power System Analysis, was
adopted as the textbook. Dynamics and control, especially in the area of power systems applications
where rotating magnetic fields are involved, is a formidable subject to students. Hence, a set of
class notes was developed in that semester to offer a tutorial approach of learning. Many examples
and codes were developed to facilitate understanding and hands-on training. A highlight of this
textbook is its many tutorial examples.

The first version of Bergen and Vittal's book was written in 1981 by Professor Bergen. Thirty-six
years have passed since then. This classic textbook has been highly recognized and helped to
educate a generation of power system engineers. Professor Bergen passed away in July 2014. As a
power systems engineer, this author would like to contribute to the field by reinterpreting the
classics of power system control and dynamics. This textbook is also a tribute to Professor Bergen.

There will be several things different from the classic textbook.

 The generator model derivation is very sophisticated in Bergen's book. In  Bergen's book, Park's transformation was employed to derive generator models. Park's transformation was conducted using matrix in real domain. Handling matrix is a sophisticated task. The alternative of Park's transformation is space vector and complex vector transformation, a concept used much more often in machines and power electronics after the 1980s. Space vector concept makes Park's transformation straightforward. In this textbook, the author will explain synchronous generator dynamics, the most formidable dynamics in power systems, using space vector concept. Readers will find that modeling dynamics in space-vector and further in the rotor reference frame an interesting and easy task. The second highlight of generator modeling part is torque derivation. Classic textbooks all use coenergy's derivation against rotor angle. In this book, the author started from physics taught in high school and evolved to the expressions in rotating machines.

 In the 1980s, power electronics and microgrids were yet to be developed. This field is well developed in the 21st century. Many techniques used in power systems for power sharing, e.g., droop control, can also be found in power electronic converter coordination. The part is now related and put into the textbook to help readers understand converter control and coordination. This is another highlight of the textbook.

Advanced control such as networked control (consensus control) were developed after 2000. Many classic engineering implementations follow advanced control framework. It is appealing to find them and interpret the intuitive engineering design with concepts and ideas from networked control. In this textbook, inter-area oscillations are explained using consensus control.

Professor Bergen's book has steady-state analysis and dynamics all together. This textbook focuses
on dynamics and control only. This author would also like to have a better flow to focus on power
system control. Starting from the beginning, ordinary differential equation, the building block of
dynamics and control, is explained using examples. Dynamic simulation and linear system analysis
are conducted for the examples. With the fundamental concept on dynamics built, readers can then
pursue the learning tasks related to power system control and dynamic stability with ease. Readers, if not familiar with coding, learn coding for dynamic simulation.

The flow of the text is to treat frequency or voltage control as control problems. For control  problems, first we discuss the plant model and its related steady-state and dynamic responses. The plant model should be identified with inputs and outputs specified. In the frequency control case, it is obvious that the output of the plant model should be frequency. The inputs are from a generator's mechanical system inputs. After setting up the plant model, we then think about how to design feedback controls to realize control objectives. After control design is conducted, we then employ dynamic simulation to verify controller performance.

The author is grateful to have the opportunity to write and publish this books. The author would like to acknowledge University of South Florida Electrical Engineering Department for providing a great environment to conduct research and teaching. The author wishes to acknowledge her family for countless support.

The book was developed from the author's class notes of Power Systems II for Spring 2016. Minyue
Ma, a Ph.D. student, was the teaching assistant for that course and helped work out examples and
homework problems for the class. A few students in the class, e.g., Abdullah Alassaf, highly
complimented the class notes, which encouraged the author to contact the CRC press for publication.
Yin Li, a Ph.D. student, built MATLAB/Simulink models in Chapter 6 Frequency and voltage control in microgrids. Yangkun Xu, another Ph.D. student drew many for Chapter 3 and Chapter 5. Graduate
students at the USF Power Systems Smart Grid Lab reviewed the book during the holiday season in
December 2016. The author wishes to acknowledge Minyue Ma and Yin Li as reviewers. The author also wishes to acknowledge Yi Yang from Eton Cooperation as a reviewer.