introduction to power electronics class 1 - kylowave - home · 2015-04-27 · introduction to power...
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Smart technology for a sustainable world
Introduction to Power ElectronicsClass 1
Julio Pimentel, CEO Kylowave Inc.
www.kylowave.comwww.kylowaveeducation.com
Department of Electronics
Carleton University, Ottawa, ON, CA
September 9th, 2013
Class 1What you will learn Why we need power electronics
Fundamentals of power electronics circuits
Functioning of some widely used power electronics devices
Classes of power electronics circuits
Examples of some basic power electronics circuits
MotivationWhat you have learned so far Digital electronics
Transistors operate in saturation or cut-off regions => switch
Very effective to process logicalinformation
Not as efficient to process analog information
Transistor Ro (output resistance) is optimum: R0 = Vt / Ic Dissipated power: P = Vsw x Ic
Cut-off: Ic=0 => R0 = infinity
Sat: Ic=Ic(min) => Ro=minimum
Transistors are of minimum size => can not process high energy signals
Analog electronics Transistors operate in the linear
region
Very effective to process analoginformation
Not so efficient to process logical information
Transistor Ro (output resistance) is not optimum: R0 = Vt / Ic
Dissipated power: P = Vsw x Ic
Transistors are of small size => can not process high energy signals
MotivationWhy Is It Exciting Technology? Power electronics is a growing field due to the
improvement in switching technologies and the need for more and more efficient switching circuits
It is the enabling technology for emerging applications CleanTech
photovoltaic and wind energy generation and Fuel cell
Electric vehicles (hybrids and plug-in cars, bikes, scooters, etc.)
Smart power system grids
Mechatronics and robotics
Biomedical devices, and many more …
MotivationSome Example Applications Heating and lighting
control
Induction heating
Fluorescent lamp ballasts
Motor drives
Battery chargers
Electric vehicles
Switching power supplies
Spacecraft power systems
Uninterruptible power supplies
Energy storage High density batteries
Flywheels
Super capacitors
Alternative power sources Photovoltaic
Wind turbines
Fuell cells
AND MANY MANY MORE
MotivationWhy power “electronics”? Objectives:
To process “analog” signals
Carrying very large amount of energy
At very high efficiency (sometimes at 95% or 98%)
Requires low loss devices: NO RESISTORS IN THE ENERGY PATH
Recall that the theoretical maximum efficiency of a:
Class A amplifier: η(max) = 50 %
Class B amplifier: η(max) = 78.5 %
Class AB amplifier: 50 % < η(max) < 78.5 %
Class C amplifier: η(max) < 90 % but @ high output distortion
MotivationWhy power “electronics”? (Cntd) Requirements
Process analog signals Uses modulation techniques (ex.: PWM Pulse Width Modulation)
Use filtering to eliminate high frequency harmonics
Process high energy signals (high current and/or high voltage) requires very large transistors
Requires very low RON values
Very high efficiency Transistors must dissipate minimum power
Transistors operate as switches (saturation and cut-off regions)
Transistor Ro (output resistance) is optimum: R0 = Vt / Ic
Dissipated power: P = Vsw x Ic
Cut-off: Ic=0 => R0 is maximum
Saturation: Ic=Ic(max) => Ro is minimum
IntroductionTypical circuit example These are valid topologies: voltage source connected to current source
These ones are not valid topologies: two sources of same type
GateiL
SW
DIdc Vdc
GateiL
SW
D IdcVdc
GateiL
SW
D Idc
GateiL
SW
D VdcVdc
The use of low loss components make these topologies not valid
IntroductionBasic Building Blocks PWM – Pulse Width Modulation - The idea is to modulate
the width of a stream of pulses, keeping the carrier frequency constant, such that the low pass frequency spectrum produces the required waveform
LP Filtered signal
HF Stream of
Pulses
PWM in Wikipedia
IntroductionBasic building blocks Inductors – driven by cte voltage source Capacitors – driven by cte current source
Diodes –2nd and 4th quadrants Switches – 1st and 3rd quadrants
C
v
i
i = C dv/dt
E = ½ * C v2
V(s)=I(s) / sC
Current integration
t
v0
i = constant
v = v0 + t i
/ C
L
v
i
V = L di/dt
E = ½ * L i2
I(s)=V(s) / sL
Voltage integration
t
i0
v = constant
i = i0
+ t v / L
vd
id
vd
id
vd(on) = Rd(on) id
E = 0
vd(off) = Rd(off) id
id
vd
On
Off
TurnOff
TurnOn
vsw
isw
vsw
isw
vsw(on) = Ron isw(on)
E = 0
vsw(off) = Roff isw(off)
TurnOff
TurnOn
IntroductionPutting it all together Spontaneous switching Forced switching
D1
D1N4002V2
FREQ = 60VAMPL = 10VOFF = 0
R1
1K
V3
FREQ = 60VAMPL = 10VOFF = 0
D2
D1N4002
L1
10uHC1
5u
0V
IV V
Gate
iLSW
C D
L
RvD
vSW
Some power electronics devicesThe ideal unidirectional switch Unidirectional => operation in the 1st quadrant
Switching controlled by Gate port
There are only two stable states: ON or OFF
Ron = 0 and Roff = ∞
Power loss = vsw x isw = 0
Turn on
vsw
isw
vsw
isw
vsw(on) = Ron isw(on)
E = 0
vsw(off) = Roff isw(off)
Turn off
Gate
Instantaneous i-v characteristicGate
iLSW
C D
L
RvD
vSW
Some power electronics devicesThe ideal diode Operation in the 2nd or 4th quadrants
Ron = 0 and Roff = ∞
Spontaneous switching: no Gate port
Switching controlled by
Turn on: voltage Vd ≥ Vth
Turn off: current Id ≤ 0
vd
id
id
vd(on) = Rd(on) id
E = 0
vd(off) = Rd(off) id vd
On
Off
Instantaneous i-v characteristic
Gate
iLSW
C D
L
RvD
vSW
Some power electronics devicesThe thyristor or SCR SCR - Semiconductor-Controlled Rectifier
Conduction only from A to K: Unidirectional switch Turn ON - by a positive pulse at the gate Turn Off – if current through SCR drops below a certain threshold
NOTE: Figures from: http://mysite.du.edu/~etuttle/electron/elect5.htm
Turn on
vsw
isw
vsw
isw
vsw(on) = Ron isw(on)
E = 0
vsw(off) = Roff isw(off)
Turn off
Gate
Instantaneous i-v characteristic
Some power electronics devicesThe Triac It is “equivalent” to two complementary unilateral thyristors in a inverse
parallel connection Conducts in both directions: bidirectional switch Turn ON - by a positive or a negative pulse at the gate Turn Off – if current through the TRIAC drops below a certain threshold
NOTE: Figures from: http://mysite.du.edu/~etuttle/electron/elect5.htm
TurnOff
TurnOn
vsw
isw
vsw
isw
vsw(on) = Ron isw(on)
E = 0
vsw(off) = Roff isw(off)
TurnOff
TurnOn
Instantaneous i-v characteristic
Some power electronics devicesThe power BJT BJT - Bipolar Junction Transistor
Conduction only from C to E: unidirectional switch
Main advantages: Very high commutation speed
good efficiency at low voltages
Very low saturation voltage VCE
Disadvantages Not isolated gate making it to be difficult to drive
Can not handle very high energy levels
NOTE: Figures from www.wikipedia.com
Turn on
vsw
isw
vsw
isw
vsw(on) = Ron isw(on)
E = 0
vsw(off) = Roff isw(off)
Turn off
Gate
Instantaneous i-v characteristic
Some power electronics devicesThe power MOSFET ) MOSFET - Metal Oxide Semiconductor Field Effect Transistor
Bidirectional switch
It is a specific type of MOSFET designed to handle significant power levels
Advantages: high commutation speed
good efficiency at low and medium voltages
isolated gate what makes it easy to drive
Disadvantage Lower speed than the BJTs
Higher saturation voltage VDS
Turn on
vsw
isw
vsw
isw
vsw(on) = Ron isw(on)
E = 0
vsw(off) = Roff isw(off)
Turn off
Gate
Instantaneous i-v characteristic
Some power electronics devicesThe IGBT (Insulated Gate Bipolar Transistor)
IGBT - Insulated Gate Bipolar Transistor
Conduction only from C to E: unidirectional switch
Advantages: high commutation speed good efficiency at medium to high voltages isolated gate what makes it easy to drive Very low saturation voltage VCE (similar to BJT)
NOTE: Figures from www.wikipedia.com
Turn on
vsw
isw
vsw
isw
vsw(on) = Ron isw(on)
E = 0
vsw(off) = Roff isw(off)
Turn off
Gate
Instantaneous i-v characteristic
Some power electronics devicesOthers power electronic devices For your information, there are many others power
electronic devices such as Diac
SIDAC
GTO - Gate Turn-off Thyristor
IGCT - Integrated Gate-Commutated Thyristor
But these ones are less common They are usually used in niche applications
Choice is based on cost, speed, power level and maximum di/dt supported by the device
Some general classes of power electronics circuits Families of solid state power converters categorized
according to their conversion function
AC
Vac1, f1
AC
Vac2, f2
DC
Vdc1
DC
Vdc2
DC-DC
Converters
AC-D
C
Rectifiers
DC-A
C
Inve
rters
DC
Link
AC
-AC
Co
nve
rte
rs
Cic
loco
nve
rte
rs
Example #1Spontaneous switching - Rectifiers
Single phase Three phaseD1
D1N4002
V2FREQ = 60VAMPL = 10VOFF = 0 R1
1K
L110uH
C1
5u
V VI
D1
D1N4002
R1
1KV2
FREQ = 60
VAMPL = 10VOFF = 0
PHASE = 120
D2
D1N4002
L110uH
C1
5u
D3
D1N4002
D4
D1N4002
D5
D1N4002
D6
D1N4002
V3
FREQ = 60
VAMPL = 10VOFF = 0
PHASE = 240
V1
FREQ = 60
VAMPL = 10VOFF = 0
PHASE = 0
I V
V
Smoothinginductance
Example #2Forced switching phase controlled rectifier DC-DC Converter
R320
V2TD = 0
TF = 10nsPW = 30uPER = 100u
V1 = 0
TR = 10ns
V2 = 2
L1
5mh
V3
20V
D1
D1N4002
C1
10n
Q1Q2N2222
R410
I
VV1
FREQ = 60
VAMPL = 50VOFF = 0
PHASE = 0
R3100
X12N1595
V2TD = 3ms
TF = 10nsPW = 0.2ms
PER = 16.6667ms
V1 = 0
TR = 10ns
V2 = 5
L1
5mh
R4
1k
V
V
V
ConclusionResources available Orcad version 16.3 Student Edition – Free
http://www.cadence.com/products/orcad/pages/downloads.aspx
NOTE: The student edition has limitations in terms of # of components, # of pins, etc.
We will publish a copy of the example circuits
The internet has many useful links Search for “ pspice and power and electronics”
References This is one of the best references
Erickson, R. W. & Maksimovic, D., “Fundamentals of Power Electronics,” 2nd Edition, University of Colorado, Boulder, http://ecee.colorado.edu/copec/book/slides/slidedir.html
These are good references as well Ramshaw, E. & Shuumman, D. C., “PSpice Simulation of Power
Electronics Circuits: An Introductory Guide,” Springer Verlag, 1996 Ferrieux, J. P. & Forest, F., “Alimentation à découpage -
Convertisseurs à résonance: principes, modélisation, composants,” Collection technologies, Masson, Paris, 1987, ISBN 2-225-81205-5
Tolyat, H. A. & Campbell, S., “DSP-Based Electromechanical Motion Control,”CRC Press, 2003
Thompson, M. T., “Introduction to Power Electronics,”, 2007, http://www.thompsonrd.com/NOTES%2001%20INTRODUCTION%20TO%20POWER%20ELECTRONICS.pdf