PE 304 Lect 1.pdf - Curtin University

Curtin University of Technology
Division of Engineering, Science and Computing
Department of Electrical and Computer Engineering
Power Electronics 304/604
Semester 2, 2008
Lecture 1
Professor Chem Nayar
Office: 204:205
Telephone: 9266 7934
Email: c.v.nayar@curtin.edu.au

Power Electronics 304/604
Tuition Pattern:
5 Hours:
Lecture 2.00 hours, 1.00 weekly
Tutorial 1.00 hour, 1.00 weekly
Laboratory 2.00 hours, 1.00 weekly
Assessment Details:
Assignments : 40%
Lab Report 1 (10%)
Lab Report 2 (10%)
Assignment (20%)
Final Examination (3hours) : 60%
(Closed Book Restricted Exam – 1 x A4 size paper
with notes on both sides allowed).

Outline -- Lecture 1
• Introduction to Course Outline
• Introduction to Power Electronics
• Basic Concepts

What is Power Electronics?
•Power electronics links the two major
traditional divisions of electrical
engineering, namely electrical power
and electronics.
•Involves the study of electronic circuits
which control the flow of energy

Definition
• Power electronics involves the study of
electronic circuits intended to control the
flow of electrical energy.
• These circuits handle energy flow at levels
much higher than individual device ratings.

Power Electronic System
The power electronics interface facilitates the transfer of power
from the source to the load by converting voltages and currents
from one form to another, in which it is possible
for the source and load to reverse roles. The controller shown in
Fig. 1-1 allows management of the power transfer process in
which the conversion of voltages andcurrents should be
achieved with as high energy-efficiency and high power density
as possible.

Components of a power electronic system
•Energy source
•Temporary energy storage or filtering
(inductance, capacitance)
•Switch(es)
•Load
•Control hardware and software
•Switch gate-drive circuitry

Introduction
Power electronics encompasses three technologies: power semiconductor,
power conversion, and power control.

Introduction
• Electronics deals with the semiconductor devices and
circuits used in signal processing to implement the
control functions, power deals with both static and
rotating equipment that uses electric power, and control
deals with the steady-state stability of the closed-loop
system during the power conversion process.
• In power electronic circuits there exist two types of
switching devices: one type in the power stage that
handles high power up to hundreds of gigawatts (which
represents the muscle of the system) and another type in
the feedback control circuit that handles low power up to
hundreds of milliwatts, representing the brain or
intelligence of the system.

The Need For Power
Conversion
• The basis of utility power system generation, transmission, and
distribution since the beginning of this century has been ac at a
fixed frequency of either 50 or 60 Hz.
• The most outstanding advantage of ac over dc is the
maintenance of high voltage over long transmission lines and the
simplicity of designing distribution networks.
• At the consumer end many applications may need dc or ac power
at line, higher, lower, or variable frequencies.
• In some cases, the generated power is from dc sources such as
batteries, fuel cells, or photovoltaic, and in other cases the
available power is generated as variable-frequency ac from
sources such as wind or gas turbines.
• The need for this power conversion, ac-to-dc, became more
acute with the invention of vacuum tubes, transistors, ICs, and
computers.

• Compared with electromechanical systems and
linear electronic systems, power electronics has
many advantages, including
– High energy conversion efficiency
– Highly integrated power electronic systems
– Reduced EMI and electronic pollution
– Higher reliability
– Use of environmentally clean voltage sources such as
photovoltaic and fuel cells to generate electric power
– The integration of electrical and mechanical systems
– Maximum adaptability and controllability

Power Electronic Systems
• Most power electronic systems consist of two major
modules:
– The power stage (forward circuit)
– The control stage (feedback circuit)
Simplified block diagram for a power electronic
system
x , x ,......, x
1
1
1
2
y , y ,...... y
p
p
in
out
2
( t)
( t)
2
m
is the total instantaneous
input power in watts
f , f ,....., f
is the total instantaneous
output power in watts
or angular
Efficiency,
η,
is
3
n
are input signals (voltage, current, or angular frequency)
are output signals (voltages, currents, or
are feedback signals : voltages or currents in an electricalsystem,
speed or angular position in a mechanicalsystem.
defined as follows :
P
η =
P
out
in
× 100%
angular frequency)

Classification of Power
Converter Circuits
Detailed block diagram of a power electronic
system
• The function of the power
converter stage is to perform the
actual power conversion and
processing of the energy from the
input to the output by
incorporating a matrix of power
switching devices
• Power conversion refers to the
power electronic circuit that
changes one of the following:
– voltage form (ac or dc)
– voltage level (magnitude)
– voltage frequency (line or
otherwise)
– Voltage waveshape
(sinusoidal or nonsinusoidal,
such as square, triangle, or
sawtooth),
– Voltage phase (single-orthree-phase)

• There are four conversion circuits that are used in the majority of
today’s power electronic circuits:
– ac-to-ac
– ac-to-dc
– dc-to-ac
– dc-to-dc
• In terms of the functional description, modern power electronic
systems perform one or more of the following conversion functions:
– Rectification (ac-todc)
– Inversion (dc-to-ac)
– Cycloconversion (ac-to-ac, different frequencies) or ac
controllers (ac-to-ac, same frequency)
– Conversion (dc-to-dc)

Rectification (ac-to-dc)
• The term rectification refers to the power circuit whose function is to
alter the ac characteristic of the line electric power to produce a
“rectified” ac power at the load site that contains the dc value.
(a)
ac-dc rectification (a) Simplified block diagram representation (b) Example of ac-dc
conversion
(b)

Inversion (dc-to-ac)
• The term inversion is used to power electronic circuits for the
function that alters the dc source (e.g. a battery) with no ac
components into an “inverted” ac power at the load that has no dc
components.
(a) (b) (c)
Dc-to-ac inversion (a) Simplified block diagram representation (b)
Example of dc-ac inversion (c) Block diagram representation with
high frequency inversion

Cycloconversion or Voltage
Controllers (ac-to-ac)
• The term cycloconversion is used for power electronic circuits that
convert the ac input power at one frequency to an ac output power
at a different frequency using one-stage conversion
(a) (b) (c)
Cycloconversion (a) One-stage ac-to-ac cycloconversion (b) Example of ac-to-ac
conversion waveforms (c) Two-stage ac-to-ac cycloconversion

Conversion (dc-to-dc)
• Dc-to-dc converters are used in power electronic circuits to convert
an unregulated input dc voltage to a regulated or variable dc output
voltage.
(a) (b)
Dc-to-dc conversion (a) One-stage dc-to-dc conversion (b) Example of
waveforms (c) Two-stage dc-to-dc conversion
(c)

Power electronic conversion system
representing four possible conversion
functions
Simplified Block Diagram representation of the power electronic conversion
function

• Load current io, and voltage vo, shown in figure below can be
either positive or negative, there exist four modes of operation as
show in (b)
(a) (b)
(a) Simple power electronic circuit with single voltage source and single load (b)
Possible converter modes of operation

Power Semiconductor Devices
• Because of the high conversion efficiency, semiconductor switching
devices are considered the heart of power electronic circuits
• Today, semiconductor switching devices have achieved
unprecedented power-handling capabilities and switching speeds.
• The devices include
– Power diodes
– Bipolar junction transistors (BJTs)
– Metal oxide semiconductor field-effect transistors (MOSFETs)
– Thyristors or silicon-controlled rectifiers such as triacs, diacs,
gate turn-off (GTO) thyristors, static induction transistors (SITs),
static induction thyristors (SITHs), and MOS-controlled thyristors
(MCTs) are, in one way or another, from the same families of
these five basic devices.

Applications of Power
Electronics
• Electrical applications
– ac and dc regulated power supplies for various
electronic equipment, including consumer electronics,
instrumentation devices, computers, aerospace, and
uninterruptible power supply (UPS) applications.
• Electromechanical applications
– used in industrial, residential, and commercial
applications
• Electrochemical applications
– includes chemical processing, electroplating, welding,
metal refining, production of chemical gases, and
fluorescent lamp ballasts

Applications of Power Electronics by
Conversion Functions (Partial List)
Conversion Function Applications
Uncontrolled ac-dc
converters (diode
circuits)
Phase-controlled
converters (thyristor
circuits)
Front-end off-line regulated dc-to-ac power supplies and
dc-ac inverters
Battery charges
Welding
Dc motor drives
Regulated dc power supplies
ac and dc variable-speed motor control
Battery chargers
Flexible ac transmission system (FACTS)
Utility interface of photovoltaic systems
Regulated ac inverters
Solid-state circuit breakers
Dc motor drives
Induction heating
Electromechanical processing (electroplating, anodizing,
metal refining)
HVDC systems
Light dimmers
Active power line conditioning (APLC)
(var compensator, harmonic filters)
Induction heating

Conversion Function Applications
dc-dc converters
High-frequency regulated dc power supplies
using both isolated and nonisolated switchmode
and soft-switching resonant
topologies
Digital and analog electronics
Solar energy conversion
High-frequency quasi-resonant converters
Electric vehicles and trams
dc-fed forklifts
Fuel cell conversion
dc traction drives
Distributed power systems
Power factor correction
Solid-state relays
Capacitor chargers

Conversion Function Applications
Linear-mode dc-dc
converters
Cycloconverters
and ac controllers
(ac-ac)
Low-power linear dc regulators
Audio amplifiers
RF amplifiers
ac motor drives
Rolling mill drives
Static Scherbius drives
Aircraft
Frequency changers
Solid-state power line conditioners
Variable-speed constant-frequency (VSCF)
systems
Fluorescent lighting
Light dimmers
Induction heating

Conversion Function Applications
dc-to-ac inverters
Static switching
Power ICs
Aircraft and space power supply systems
Ac variable-speed motor devices (lifts)
Uninterruptible power supplies (UPS)
Power factor correction
Light dimmers
Electric railroad systems
Magnetically levitated (maglev) high-speed
transportation systems
Electric vehicles
ac and dc circuit breakers
Circuit protection
Solid-state relays
Home and office automation
Automobiles
Telecommunications
ac and dc drives
dc power supplies

Applications and the Role of Power
Lighting 19%
IT
14%
HVAC 16%
Energy consumption in the US
Electronics
Motors 51%

Information and Communication

Electric Welding

Adjustable Speed Drives

Transportation
Hybrid cars

Photovoltaic Power Systems
(a)
DC Input
Power
Electronics
Interface
(b)
Utility

Wind Electric Systems
Generator
and
Power Electronics
Utility

Summarizing the Role of Power
Electronics

Efficiency is critical

Devices available to Designers

Devices available to Designers

Devices available to Designers

Power loss in an ideal Switch

Example: DC-DC Converter

DC-DC Converter Example

DC-DC Converter : Linear Power Supply
•Series transistor as an adjustable resistor
•Low Efficiency
•Heavy and bulky

DC-DC Converter : Use of a Single
Pole Double Throw (SPDT)Switch

The switch changes the dc level

Addition of low pass filter

Addition of Control System : Switch
mode Power supply

Switch-Mode Power Supply with
• Transistor as a switch
• High Efficiency
• High-Frequency Transformer
Isolation

Power Electronics 304/604: The Syllabus
• Applications and Structure of Switch-Mode
Power Electronics
• Simulation of power electronic circuits
• Review of Magnetic Concepts
• Diode Rectifiers and their Design
• DC-DC Converters: Switching Details and
their Average Dynamic Models
• Design of High-Frequency Inductors

Recommended Texts and Principal References
1. Ned Mohan, Tore M. Undeland and William P. Robbins, Power
Electronics Converters, Applications, and Design, Second/third
Edition, John Wiley, 2003 (TK7881.15.M64)
2. Daniel W. Hart, Introduction to Power Electronics, Prentice Hall,
1997 (TK7881.15.H37)
3. John G. Kassakian, Martin F. Schlecht, and George C. Verghese,
Principles of Power Electronics, Addison-Wesley, 1991
(TK7881.15.K37).
4. Philip T. Krein, Elements of Power Electronics, Oxford University
Press, 1998 (TK7881.15.K74)
5. Muhammad H. Rashid, Power Electronics Circuits, Devices,
and Applications, 3rd edition, Prentice-Hall, 2004
(TK7881.15.R37)
6. Issa Batarseh, Power Electronics Circuits, John Wiley, 2004

Week
1
2
3
4
5
6
7
8
9
10
11
12
13
Power Electronics 304/604
Day
28-Jul
4-Aug
11-Aug
18-Aug
1-Sept
8-Sept
15-Sept
22-Sept
6-Oct
13-Oct
20-Oct
27-Oct
3-Nov
Introduction
DC-DC Converters 1
DC-DC Converters 2
DC-DC Converters 3
DC-DC Converters 4
Inductor Design
Revision
Fundamentals of
Electric Circuit
& Magnetics
Overview of
Semiconductor
Switching
Devices
Rectifier Circuits 1
Rectifier Circuits 2
Rectifier Circuits 3
Study week
Pre-readings
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
PE 304 Notes
Tutorial
Tutorial No.1
Tutorial No.2
Tutorial No.3
Tutorial No.4
Tutorial No.5
Tutorial No.6
Tutorial No.7
Tutorial No.8
Tutorial No.9
Tutorial No.10
Assignment Due
Lab Report 1 (Group)
Lab Report 2 (Group) +
Assignment (
individual)

Power Electronics Lab +Report & Assignments
2 hour lab per week as a group – alternate between practical and computer lab
Week 2 4/08/2008 Digital Osciloscope-Familirisation
Week 3 11/08/2008 Single Phsse Rectifier
Week 4 18/08/2008 Single Phsse Rectifier
Week 5 25/08/2008 Tuition Free Week
Week 6 1/09/2008 Three Phase Rectifier
Week 7 8/09/2008 Three Phase Rectifier
Week 8 15/09/2008 Catch Up Lab
Week 9 22/09/2008 Buck Converter Report 1 ( Group)
Week 10 29/09/2008 Tuition Free Week
Week 11 6/10/2008 Buck Converter
Week 12 13/10/2008 Boost Converter
Week 13 20/10/2008 Boost Converter
Week 14 27/10/2008 Buck-Boost Converter
Week 15 3/11/2008 Study Week Report 2 ( Group )
Assignment (individual)