2
● Energy Source and Load
- Source:
- Load:
● Conventional Resistive Solution
R x I
O

V
B
V
O

R o
Controller
- Control low:
- Ohmic loss at:
2
2

3
● Assumptions:
R x I
O

V
B
60 W @ 12 V V
O

Controller
P loss
:
- Efficiency :
● Consequence of poor efficiency
3
3

4
4
V
B
Switch network a
 p v
X

 v
O

Controller
V
B v
O v
X
T on
T s
● Control law:
● No power loss in circuit
:
4

5
5
● Power conversion: Changing electrical energy/power from one form to another form using electronics devices
Examples:
● Power electronics: Electronic engineering that deals with all types of power conversions while questing the
● Dc-to-Dc power conversion: Process of changing the voltage level of a dc source to another value
5

6
6
6

7
Dc source
Power stage
Controller
Dc-to-dc converter
● Dc source with non-ideal characteristics
- Standalone dc source:
- Rectified ac source:
● Load as dynamic current sink with non-resistive impedance
- Electric equipment: non-resistive load impedance
Load
7
7

8
Dc source
Power stage
Controller
Dc-to-dc converter
● Dc-to-dc converter as voltage source
• Function of dc-to-dc converter:
• Elements of dc-to-dc converter
- Power stage: semiconductor switch
Load
8
8

9
9
● Power stage components
- Semiconductors: high frequency switching
- Inductors and capacitors: periodic voltage/current excitation
- Transformers: periodic voltage/current excitation
● Power stage configurations
- Accommodation of input voltage and load current requirements
- Very large or very small voltage conversion ratio
- Galvanic isolation between source and load
● Dynamic modeling and analysis
- Closed-loop feedback control: stability
- Dynamic modeling to accommodate conventional analysis technique
● Dynamic performance and controller design
- Static and dynamic performance
- Dynamic performance: stability, transfer functions, transient responses
- Feedback controller design for optimal dynamic performance
9

●
General Information
Office: IT3-314 Office Hour: Fri 9:00-12:00 AM
Phone: 950-6603, Home Page: http://m80.knu.ac.kr/~SMPC/
●
Course Objective: As an introductory course in power electronics, the class will address basic principles, analysis techniques, and applications of modern power electronics with a strong emphasis on switchmode dc-to-dc power conversions. The students would learn methods of solving various power electronics problems using their knowledge about electronics, circuit theories, and control theories.
●
Text: Byungcho Choi , “Fundamentals of Switchmode Dc-to-Dc Power Conversions.
2 nd Edition, 2010, Young Publishing http://www.bandinlunis.com/front/product/detailProduct.do?prodId=3196848
Reference: R.W. Erickson, “Fundamentals of Power Electronics,” 1997.
D. W. Hart, “Introduction to Power Electronics,” 1997, Prentice-Hall
P. T. Krein, “Elements of Power Electronics,” 1998, Oxford

Tentative Course Outline
Topic
Chapter 1: Basics of
Power Electronics
Chapter 2: Step-down Dc-to-D c Power Conversion Circuit:
Buck Converter
Chapter 3: Dc-to-Dc Power Co nverter Circuits
Chapter 3: Dc-to-Dc Power Co nverter Circuits
Chapters 4, 5, and 6: Modeling
, Control Design and
Analysis of PWM Converters
Major Contents
 Introduction to power electronics
 Semiconductor switches and switching circuits
 Energy storage/transfer devices and switching circuits
 Basic principles of buck converter
 Time-domain analysis of buck converter
 Discontinuous-conduction mode of operation
 Closed-loop control of buck converter
 Step-up dc-to-dc converter
 Buck/boost converter
Midterm Test
 Flyback converters
 Bridge-type converters
 Forward converters
 Average modeling of PWM converters
 Small-signal modeling of PWM converters
 Small-signal analysis of PWM dc-to-dc converters
 Compensation design and closed-loop analysis
Final Exam
 Grading Policy:
Midterm Test: 42%, Final Exam: 42%, Homework: 16%
 Honor System:
Students should develop their own solutions to homework problems.
Late homework will not be accepted with no exceptions.
Week
3 weeks
3 week
1 week
2 weeks
4 weeks