Chapter 1
Introduction
Outline
I.
What is power electronics?
Power
II. The history
III. Applications
IV. A simple example
V. About this course
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I.
What is power electronics?
1) Definition
2) Relation with information electronics
Power
3) The interdisciplinary nature
4) Position and significance in the human society
3
1) Definition
Power Electronics:
is the electronics applied to conversion and control of
electric power.
Range of power scale :
Power
milliwatts(mW)
megawatts(MW)
gigawatts(GW)
A more exact explanation:
The primary task of power electronics is to process and
control the flow of electric energy by supplying voltages
and currents in a form that is optimally suited for user
loads.
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Conversion of electric power
Power
input
Electric
Power
Converter
Power
output
Power
Control
input
Other names for electric
power converter:
-Power converter
-Converter
-Switching converter
-Power electronic circuit
-Power electronic converter
Two types of electric power
Changeable properties in
conversion
DC(Direct Current)
Magnitude
AC (Alternating Current)
Frequency, magnitude,
number of phases
5
Classification of power converters
Power
Power
input
Power
output
DC
AC
AC
AC to AC converter
AC to DC converter ( Fixed frequency : AC controller
(Rectifier)
Variable frequency: Cycloconverter
or frequency converter)
DC
DC to DC converter
(Chopper)
DC to AC converter
(Inverter)
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Power electronic system
Generic structure of a power electronic system
Power
input
Power
Power
output
Converter
Control input
Power
Feedforward/Feedback
Controller
( measurements of input signals )
Feedback/Feedforward
( measurements of output signals )
Reference
(commanding)
Control is invariably required.
Power converter along with its controller including the
corresponding measurement and interface circuits, is
also called power electronic system.
7
Typical power sources and loads
for a power electronic system
Source
Power input
Vi
ii
Power
-Electric utility
-battery
-other electric energy source
-power converter
Power
Converter
Power output
io
Feedback/
Feed forward
Controller
Reference
Vo
Load
-Electric Motor
-light
-heating
-power converter
-other electric or
electronic equipment
The task of power electronics has been recently
extended to also ensuring the currents and power
consumed by power converters and loads to meet
the requirement of electric energy sources.
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2) Relation with information electronics
A Classification of electronics by processing object
Information electronics: to process information
Electronics
Power electronics:
to process electric power
Power
Other classifications of electronics
Electronics
Vacuum electronics: using vacuum devices,
e.g, vacuum tubes devices
Solid (Solid state) electronics: using solid state devices,
e.g, semiconductor devices
Electronics
Physical electronics: physics,material,fabrication,
and manufacturing of electronic
devices
Applied electronics: application of electronic
devices to various areas
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3) The interdisciplinary nature
William E. Newell’s description
Electronics
Power
Power
Power
Electronics
Continuous,
discrete
Control
Power electronics is the interface between
electronics and power.
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Relation with multiple disciplines
Systems &
Control theory
Signal
processing
Circuit
theory
Power
Electric
machines
Simulation &
computing
Power
electronics
Power
systems
Electronics
Solid state
physics
Electromagnetics
Power electronics is currently the most active
discipline in electric power engineering worldwide.
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4) Position and significance
in the human society
Electric power is used in almost every aspect and
everywhere of modern human society.
Power
Electric power is the major form of energy source
used in modern human society.
The objective of power electronics is exactly about
how to use electric power, and how to use it
effectively and efficiently, and how to improve the
quality and utilization of electric power.
Power electronics and information electronics make
two poles of modern technology and human
society—— information electronics is the brain,and
power electronics is the muscle.
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II.
The history
Power
Application of
fast-switching
Invention of
fully-controlled
Thyristor
semiconductor
devices
GTO
GTR
Mercury arc rectifier
Power MOSFET
Power diode
Vacuum-tube rectifier
Thyristor
Thyristor
Thyratron
(microprocessor)
1900
1957
Pre-history
late 1980s
mid 1970s
1st phase
IGBT
Power MOSFET
Thyristor
(DSP)
2nd phase
3rd phase
The thread of the power electronics history precisely
follows and matches the break-through and evolution
of power electronic devices
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III. Applications
Industrial
Transportation
Utility systems
Power
Power supplies for all kinds of electronic equipment
Residential and home appliances
Space technology
Other applications
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Industrial applications
Motor drives
Electrolysis
Electroplating
Power
Induction heating
Welding
Arc furnaces and ovens
Lighting
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Transportation applications
Trains & locomotives
Subways
Trolley buses
Power
Magnetic levitation
Electric vehicles
Automotive electronics
Ship power systems
Aircraft power systems
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Power
Utility systems applications
High-voltage dc
transmission(HVDC)
Flexible ac transmission(FACTS)
Static var compensation &
harmonics suppression: TCR,
TSC, SVG, APF
Custom power & power quality
control
Supplemental energy sources :
wind, photovoltaic, fuel cells
Energy storage systems
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Power supplies for electronic equipment
Telecommunications
Computers
Power
Office equipment
server
computer
Electronic instruments
Portable or mobile
electronics
Telecommunication
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Residential and home appliances
Lighting
Heating
Air conditioning
Power
Refrigeration & freezers
Cooking
Cleaning
Entertaining
19
Applications in space technology
Spaceship power systems
Power
Satellite power systems
Space vehicle power
systems
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Other applications
Nuclear reactor control
Power
Power systems for
particle accelerators
Environmental
engineering
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Trends
It is estimated that in developed countries now 60%
of the electric energy goes through some kind of
power electronics converters before it is finally used.
Power
Power electronics has been making major
contributions to:
--better performance of power supplies and better control of
electric equipment
--energy saving
--environment protection
reduction of energy consumption leads to less pollution
reduction of pollution produced by power converters
direct applications to environment protection technology
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IV. A simple example
Power
A simple dc-dc converter example
Input source:100V
Output load:50V, 10A, 500W
How can this converter be realized?
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Dissipative realization
Power
Resistive voltage divider
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Dissipative realization
Power
Series pass regulator:
transistor operates in active region
25
Power
Use of a SPDT switch
SPDT: Single pole double throw
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Power
The switch changes the dc voltage level
27
Addition of low pass filter
Power
Addition of (ideally lossless) L-C low-pass filter, for
removal of switching harmonics:
Choose filter cutoff frequency f0 much smaller than
switching frequency fs
This circuit is known as the “buck converter”
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Power
Addition of control system for
regulation of output voltage
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Major issues in power electronics
How to meet the requirement of the load or gain better
control of the load
Power
How to improve the efficiency
--for reliable operation of power semiconductor
devices
--for energy saving
How to realize power conversion with less volume, less
weight, and less cost
How to reduce negative influence to other equipment in
the electric power system and to the electromagnetic
environment
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V.
About this course
Power
Four parts of the content
Power electronic devices:
Chapter 2 and 9
Power electronic circuits:
Chapter 3, 4, 5 and 6
Control techniques:
Chapter 7 and 8
Applications:
Chapter 10
Relation with other courses
Continuing course
Pre-requisite course
Fundamentals
of analog / digital
electronics
Power
electronics
Control systems
for electric
drives
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Arrangement
Text books
Power
- 王兆安，刘进军。《电力电子技术》。北京：机械工业出版社，
2009
- N. Mohan, T. M. Undeland, W. P. Robbins. Power edectronics:
converter, applications, and Design, 3rd edition, John Wiley &
Sons, New York, 2003, Higher Education Press, Beijing, China,
2004
Lectures
- 48 hours , all in English
- After-class reading in Chinese and English will be assigned.
Labs
- 8 hours, 5 projects
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