electronics - knu
TRANSCRIPT
POWER ELECTRONICS withPULSEWIDTH MODULATEDDC-TO-DC POWER CONVERSION
by BYUNGCHO CHOI
POWER ELECTRONICS
● General InformationOffice: IT3-314 Office Hour: Fri 9:00-12:00 AMPhone: 950-6603, Home Page: http://m80.knu.ac.kr/~SMPC/Email: [email protected] Lab: Sep 30th – Oct 6th IT2-114 7:00-9:00 PMClass Changes: Nov 1st week Æ Nov 7th (sat) 1:30 PM- (ELEC2) 4:00 PM- (ELEC3)
Nov 14th (sat) 1:30 PM- (ELEC2) 4:00 PM- (ELEC3) ● 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 variouspower electronics problems using their knowledge about electronics, circuit theories, and control theories.
● Text: Byungcho Choi, “Pulsewidth Modulated Dc-to-Dc Power Conversion:Circuits, Dynamics, and Control Designs, 2013, Wiley.
y Grading Policy:Midterm Test: 40%, Final Exam: 40%,Homework and Project: 20%
y Honor System:Students should develop their own solutions to homeworkproblems.Late homework will not be accepted with no exceptions.
Tentative Course Outline
Topic Major Contents WeeksChapter 1: PWM Dc-to-Dc Power
ConversionChapter 2: Power Stage
Components
y Introduction to PWM dc-to-dc power conversiony Semiconductor switches and switching circuitsy Energy storage/transfer devices and switching circuitsy Switch circuits in practice
2 weeks
Chapter 3: Buck Converter y Basic principles of buck convertery Time-domain analysis of buck convertery Discontinuous-conduction mode of operationy Closed-loop control of buck converter
2 weeks
Chapter 4: Dc-to-Dc Power Converter Circuits
y Boost convertery Buck/boost convertery Flyback convertery Isolated converter topologies
2 weeks
Midterm TestChapter 5: Modeling PWM Dc-to-
Dc ConvertersChapter 6: Power Stage Transfer
Functions
y Averaging power stage dynamicsy Linearizing averaged power stage dynamicsy Bode plot for transfer functionsy Power stage dynamics of three basic converters
3 weeks
Chapter 7: Dynamic Performance of PWM Dc-to-Dc Converters
Chapter 8: Closed-Loop Performance and Feedback Design
yFrequency-domain performance of dc-to-dc convertersyTime-domain performance of dc-to-dc convertersy Stability of dc-to-dc convertersy Compensation design and closed-loop analysis
4 weeks
Final Exam
PULSEWIDTH MODULATEDDC-TO-DC POWER CONVERSIONCircuits, Dynamics, and Control Designs
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Contents in BriefPart One : Circuits for Dc-to-Dc Conversion
Chapter 1: PWM Dc-to-Dc Power ConversionChapter 2: Power Stage ComponentsChapter 3: Buck ConverterChapter 4: Dc-to-Dc Power Converter Circuits
Part Two: Modeling, Dynamics, and Design of PWM Dc-to-Dc Converters Chapter 5: Modeling PWM Dc-to-Dc ConvertersChapter 6: Power Stage Transfer FunctionsChapter 7: Dynamic Performance of PWM Dc-to-Dc ConvertersChapter 8: Closed-Loop Performance and Feedback CompensationChapter 9: Practical Considerations in Modeling, Analysis, and Design of
PWM Converters
Part Three : Current Mode Control
Chapter 10: Current Mode Control-Functional Basics and Classical Analysis
Chapter 11: Current Mode Control-Sampling Effects and New Control Design
Procedures
PWM Dc-to-Dc Power Conversion
Pulsewidth Modulated Dc-to-Dc Power Conversion. By Byungcho ChoiCopyright © 2013 IEEE, Published by John Wiley & Sons, Inc
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Chapter Outline
1) PWM Dc-to-Dc Power Conversion
Dc-to-Dc Power Conversion
PWM Technique
2) Dc-to-Dc Power Conversion System
3) Features and Issues of PWM Dc-to-Dc Converter
8
88
Electric Bulb Drive CircuitPW
M D
c-to
-Dc
Pow
er C
onve
rsio
n
Energy source and loadSource: battery with variable output voltage Load: electric bulb
•
( V V)
V ( V)B
O
V
V
= -=
18 30
12 12
Conventional resistive solution·
Control law: = = VoO B
x o
RV V
R R+12
= ==
Ohmic loss at : ( )
x loss in out O B O O
O B O
R P P P I V I V
I V V
- --
Controller
xR IO
VB RoV
+
-
O
9
99
Problem of Resistive Solution
Efficiency evaluationAssumptions
Battery voltage: Bulb: 60 W power at voltage level and
Efficiency:
V
V V / A
( ) ( ) W
.
B
O O
loss O B O
out out
in out loss
V
V I
P I V V
P Pη
P P P
·
== = =
= - = - =
= = = =+ +
30
12 12 60 12 5
5 30 12 90
600 4
60 90
Consequence of poor efficiencyHeat generation Requirement of coolingsystem
Increase in weight and size of bulb drive circuit
·
PW
M D
c-to
-Dc
Pow
er C
onve
rsio
n
Controller
xR IO
VB RoV
+
-
O
10
1010
SPDT Switch
Single-pole double-throw (SPDT) switch contains one pole which is always connected to one of the two contacts: the throw a and the throw p.
·
PW
M D
c-to
-Dc
Pow
er C
onve
rsio
n
SPDT switch is usually implemented using MOSFET-diode pair.·
11
1111
Dc-to-Dc Power Conversion as Alternative Solution
Control law: average( ) { ( )} ( ) VonO O X X B
s
Tv t V v t v t V
T· » = = = = 12
No power loss in circuit %η· = 100
Two steps in dc-to-dc power conversion i) conversionof dc voltage into a pulse waveform ii) filtering of the pulse waveform into another dc voltage
·
PW
M D
c-to
-Dc
Pow
er C
onve
rsio
n
Controller
VB
vX
VB
onT
offT
vO
p
v
+
-
X
0V 0 V
v
+
-
O oR
oR v
+
-
O
onT
sT
12
1212
Pulsewidth Modulation for Output Voltage Regulation
BV = 24 V
sT μ=10 s
30 V
onT
μ
5 s
�24 V
Xv
Ov
Xv
sT μ=10 s
�
sT μ=10 s
sT μ=10 s
onT
μ
5 s
onT
μ
4 s
Ov
Control law: Von onB B
s s
T TV V
T T
¢¢· = = 12
Output remains constant in spite of input voltage variationOutput voltage regulation using pulsewidth modulation(PWM) scheme
·
PW
M D
c-to
-Dc
Pow
er C
onve
rsio
n
13
1313
PWM Dc-to-Dc Converter
Power conversion: changing electrical energy/power from one form to anotherformusing electric devices
·
Power electronics: electronic engineering that deals with all types of powerconversions
·whilequesting the maximum possible conversion
efficiency
Dc-to-dc power conversion: process of changing the voltage level of a dc source to another value·
PWMdc-to-dc power converter: dc-to-dc conversion circuit operating under thePWM technique
·
PW
M D
c-to
-Dc
Pow
er C
onve
rsio
n