Post on 04-Nov-2020
By: Dr. Shahram Javadi1
Power Electronics
By: Dr. Shahram JavadiDepartment of Electrical Engineering
Sh.javadi@iauctb.ac.ir
By: Dr. Shahram Javadi
Syllabus Outline
1. Introduction To Power Electronic2. Power Diodes
3. Diode Rectifiers
4. Thyristors
5. Control Rectifiers
6. AC Voltage Controllers
7. Thyristor Commutation Techniques
8. Power Transistors
9. DC to DC Choppers
10. DC to AC Inverters
2
By: Dr. Shahram Javadi
Muhammad H. Rashid
“Power Electronics”,3rd Edition,
Prentice Hall, 2004
•Text books: •Sources!!!
3
By: Dr. Shahram Javadi
COURSE EVALUATION
COURSE WORK
(Continuous Assessment)10%
Assignment & Quiz 20%
FINAL EXAMINATION 70%
TOTAL 100%
7
By: Dr. Shahram Javadi8
Lecture 1: Introduction to Power Electronics
By: Dr. Shahram Javadi9
Power
Electrical Power Generation
Transmission
Distribution
Electronics
Deals with the study of power semiconductor switching devices and their V-I characteristics.
Electronic circuits using these power devices for power conversion and output power control for Various applications.
By: Dr. Shahram Javadi10
History of Power Electronics
Mercury arc rectifier (year 1900).
Metal tank rectifier.
Grid controlled vacuum tube rectifier.
SCR (Silicon Controlled Rectifier)• The 1st Thyristor developed by Bell labs in
1956.
• 1st Commercial grade SCR developed by
“ General Electric Co. “ in 1958.
By: Dr. Shahram Javadi11
Power Electronic Applications
Commercial Applications
Air conditioners
Central refrigeration.
UPS
Elevators
Emergency lamps
Heating systems
Domestic Applications
Cooking equipments.
Lighting & heating
Air conditioners.
Refrigerators.
Freezers.
Personal Computers.
By: Dr. Shahram Javadi12
Power Electronic Applications
Telecommunications
Battery chargers.
DC power supply & UPS
Mobile cell phone battery chargers.
Transportation
Traction control of electric vehicles.
Battery chargers for electric vehicles.
Electric locomotives.
Street cars & trolley buses.
By: Dr. Shahram Javadi13
Power Electronic Applications
Utility Systems
High voltage DC transmissions (HVDC).
Static VAR compensation.
Fuel cells.
Energy storage systems
Boiler feed water systems.
By: Dr. Shahram Javadi14
Function of Power Electronics in Utility Applications
Enabling technology providing interface between two (ac/dc) electrical systems
E.g.
Interconnection of two asynchronous ac systems
dc to ac conversion is required to connect fuel cells or photovoltaics to the utility grid
Converter
Controller
Source Load
By: Dr. Shahram Javadi15
Listing of Power Electronic Applications
Distributed generation (DG)
Renewable resources (wind and photovoltaic)
Fuel cells and micro-turbines
Storage: batteries, super-conducting magnetic energy storage, flywheels
Power electronics loads: Adjustable speed drives
Power quality solutions
Dual feeders
Uninterruptible power supplies
Dynamic voltage restorers
Transmission and distribution (T&D)
High voltage dc (HVDC) and medium voltage dc
Flexible AC Transmission Systems (FACTS): Shunt and Series compensation, and the unified power flow controller
By: Dr. Shahram Javadi16
Power Device Capabilities & Resulting Power Electronic Structures
Power Semiconductor Devices and their Capabilities Polarity of voltage blocked and direction of current conduction Switching speeds and power ratings
IGBT MOSFET
Thyristor IGCT
101 102 103 104
102
104
106
108
Thyri
stor
IGBT
MOSFET
Pow
er (
VA
)
Switching Frequency (Hz)
IGCT
By: Dr. Shahram Javadi17
History
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Structure of Power Electronic Systems
Voltage-Link Systems
Transistors and diodes that can block voltage of only one polarity
Current-Link Systems
higher power bipolar voltage-blocking capabilities of thyristors
Solid State Switches
bidirectional voltage blockingand current conduction
AC1 AC2
AC1 AC2
By: Dr. Shahram Javadi19
Role of Power Electronics in Important Utility Applications
Distributed Generation (DG) Applications Power electronic interface depends on the source characteristics
AC
DC
DC
AC
Wound rotor
Induction Generator
Generator-side
Converter
Grid-side
Converter
Wind
Turbine
Isolated
DC-DC
Converter
PWM
Converter
Max. Power-
point Tracker
Utility
1f
Wind Power Generation with
Doubly Fed Induction Motors
Photo-voltaics Interface
By: Dr. Shahram Javadi20
Role of Power Electronics in Important Utility Applications
Power Electronic Loads: Adjustable Speed Drives
Controller
Motor
Utility
Rectifier
Switch-mode
Converter
By: Dr. Shahram Javadi21
Role of Power Electronics in Important Utility Applications
Power Quality Solutions for
• voltage distortion
• unbalances
• voltage sags and swells
• power outage
Load
Feeder 1
Feeder 2
Dual Feeders
Power Electronic
InterfaceLoad
Dynamic Voltage Restorers (DVR)
Uninterruptible Power Supplies
Rectifier Inverter FilterCritical
Load
Energy
Storage
By: Dr. Shahram Javadi22
Role of Power Electronics in Important Utility Applications
Transmission and Distribution: DC Transmission
most flexible solution for connection of two ac systems
AC1 AC2
HVDC
AC1 AC2
MVDC
By: Dr. Shahram Javadi23
Role of Power Electronics in Important Utility Applications
Transmission and Distribution: Flexible AC Transmission Systems (FACTS)
1 2 sinE E
PX
1E
2E
3E
+- 3E1E 2E
Shunt
converter
Series
converter
I
Shunt and Series Compensation
Series Compensation
Shunt Compensation
Utility
STATCOM
jX
By: Dr. Shahram Javadi24
Power Devices
Power diodes
Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
Bipolar Junction Transistor (BJT)
Insulated Gate Bipolar Transistor (IGBT)
Thyristors (SCR, GTO, MCT)
By: Dr. Shahram Javadi25
By: Dr. Shahram Javadi26
Applications of Power Devices
By: Dr. Shahram Javadi27
Power Diode
By: Dr. Shahram Javadi28
Diode Characteristics
By: Dr. Shahram Javadi29
Comparison between different types of Diodes
General Purpose Diodes
Fast Recovery Diodes
Schottky Diodes
Upto 6000V & 3500A
Upto 6000V and 1100A
Upto 100V and 300A
Reverse recovery time – High
Reverse recovery time – Low
Reverse recovery time – Extremely low.
25rrt s 0.1 s to 5 srrt a few nano secrrt
By: Dr. Shahram Javadi30
General Purpose Diodes
Fast Recovery Diodes
Schottky Diodes
Turn off time –High
Turn off time –Low
Turn off time –Extremely low
Switching frequency – Low
(Max 1KHz)
Switching frequency – High
(Max 20KHz)
Switching frequency – Very high.
(Max 30KHz)
0.7 to 1.2VFV 0.8 to 1.5VFV 0.4 to 0.6VFV
Comparison between different types of Diodes
By: Dr. Shahram Javadi31
BJT
By: Dr. Shahram Javadi32
BJT Characteristics
By: Dr. Shahram Javadi33
BJT Switching Times
By: Dr. Shahram Javadi34
MOSFET
By: Dr. Shahram Javadi35
n-channel Enhancement MOSFET Characteristics
Drain Characteristics
VGS1
VGS2
VGS3
Linearregion
Saturationregion
VDSVDS
ID
By: Dr. Shahram Javadi36
n-channel Depletion MOSFET
VGS
ID
+ +
G
S
D
VDS
By: Dr. Shahram Javadi37
Drain Characteristics
VGS1
VGS2
VGS3
Linearregion
Saturationregion
VDS
ID
By: Dr. Shahram Javadi38
Transfer Characteristics of MOSFET
VGS
ID
IDSS
VGS(OFF)
By: Dr. Shahram Javadi39
Switching Times of MOSFET
t
V1
VGSP
V1
VG
VT
td(on) td(off)
trtf
By: Dr. Shahram Javadi40
Semiconductor Cross-section of IGBT
By: Dr. Shahram Javadi41
IGBT
By: Dr. Shahram Javadi42
Characteristics of IGBT CM 400HA-24H
Output collector characteristics
0 2 4 6 8 10
V (Volts)CE
160
320
640
800
480I
AMPSC
V =15VGE
12
8
V =10VGE
V =7VGE
V =9VGE
By: Dr. Shahram Javadi43
Transfer Characteristics of IGBT
2 4 6 8 10 12 14
160
320
480
640
800
0
V =10VCE
T=125 Cj
0
T=25 Cj
0
VGE(TH)
VGE
I
AMPSC
I Vs V CharacteristicsC GE
By: Dr. Shahram Javadi44
Advantages of IGBT
Combines the advantages of BJT & MOSFET
High input impedance like MOSFET
Voltage controlled device like MOSFET
Simple gate drive, Lower switching loss
Low on state conduction power loss like BJT
Higher current capability & higher switching speed than a BJT. ( Switching speed lower than MOSFET)
By: Dr. Shahram Javadi45
Applications of IGBT
ac and dc motor controls.
General purpose inverters.
Uninterrupted Power Supply (UPS).
Welding Equipments.
Numerical control, Cutting tools.
Robotics & Induction heating.
By: Dr. Shahram Javadi46
DEVICE SYMBOLS & CHARACTERISTICS
By: Dr. Shahram Javadi47
Control Characteristics of Power Devices
By: Dr. Shahram Javadi48
Control Characteristics of Power Devices
By: Dr. Shahram Javadi49
Control Characteristics of Power Devices
By: Dr. Shahram Javadi50
Control Characteristics of Power Devices
By: Dr. Shahram Javadi51
Comparison between different commonly used Thyristors
Line Commutated Thyristors available up to 6000V, 4500A.
Ex: Converter grade (line commutated) SCR.
V / I rating: 5KV / 5000A
Max. Frequency: 60Hz.
Switching time: 100 to 400sec.
On state resistance: 0.45m.
By: Dr. Shahram Javadi52
Example of Inverter Grade Thyristor Ratings
V / I rating: 4500V / 3000A.
Max. Frequency: 20KHz.
Switching time: 20 to 100sec.
On state resistance: 0.5m.
By: Dr. Shahram Javadi53
Example of Triac Ratings
Used in heat / light control, ac motor control circuit
V / I rating: 1200V / 300A.
Max. Frequency: 400Hz.
Switching time: 200 to 400sec.
On state resistance: 3.6m.
By: Dr. Shahram Javadi54
Example of Power Transistor Ratings
PT ratings go up to 1200V / 400A.
PT normally operated as a switch in CE config.
Max. Frequency: 400Hz.
Switching time: 200 to 400sec.
On state resistance: 3.6m.
By: Dr. Shahram Javadi55
Example of Power MOSFET Ratings
Used in high speed power converters like inverters & choppers.
Ratings up to 1000V / 100A.
Example: MOSFET 800V / 7.5A rating.
Max. Frequency: 100KHz.
Switching time: 1.6sec.
On state resistance: 1.2m.
By: Dr. Shahram Javadi56
Example of IGBT Ratings
Used in high voltage / current & high frequency switching power applications (Inverters, SMPS).
Example: IGBT 2500V / 2400A.
Max. Frequency: 20KHz.
Switching time: 5 to sec.
On state resistance: 2.3m.
By: Dr. Shahram Javadi57
Switch applications
• Single quadrant switches
• Current-bidirectional two-quadrant switches
• Voltage-bidirectional two-quadrant switch
• Four-quadrant switches
• Synchronous rectifiers
By: Dr. Shahram Javadi58
The types of restricted switches
By: Dr. Shahram Javadi59
Some basic switch applications
By: Dr. Shahram Javadi60
A) Single-quadrant switches
The diode
By: Dr. Shahram Javadi61
A) Single-quadrant switches
• The Bipolar Junction Transistor (BJT) and
• The Insulated Gate Bipolar Transistor (IGBT)
By: Dr. Shahram Javadi62
A) Single-quadrant switches
The Metal-Oxide Semiconductor Field Effect Transistor (MOSFET)
By: Dr. Shahram Javadi63
B) Current-bidirectional two-quadrant switches
By: Dr. Shahram Javadi64MOSFET body diode
B) Current-bidirectional two-quadrant switches
By: Dr. Shahram Javadi65
C) Voltage-bidirectional two-quadrant switches
By: Dr. Shahram Javadi66
D) Four-quadrant switches
By: Dr. Shahram Javadi67
D) Three ways to realize a four-quadrant switch
By: Dr. Shahram Javadi68
E) Synchronous rectifiers
By: Dr. Shahram Javadi69
Switches comparison
Device TypeYear
made
Rated
Voltage
Rated
Current
Switching
Frequency
Rated
Power
Drive
CircuitComments
SCR 1957 6kV 3.5kA 500Hz 100s MW SimpleCannot turn-off using
gate signal
GTO 1962 4.5kV 3kA 2kHz 10s MWVery
Difficult
King in very high
power
BJT 1960s 1.2kV 400A 5kHz 1 MW DifficultPhasing out in new
product
MOSFET 1976 500V 200A 1MHz 100 kWVery
Simple
Good performance in
high frequency
IGBT 1983 3.3kV 1.2kA 100kHz 100s kWVery
Simple
Best overall
performance
By: Dr. Shahram Javadi70
Different types of Power Converters
Diode rectifiers (uncontrolled rectifiers).
Line commutated converters or AC to DC converters (controlled rectifiers).
AC voltage (RMS voltage) controllers (AC to AC converters).
Cyclo-converters (AC to AC converters at low output frequency).
DC choppers (DC to DC converters).
Inverters (DC to AC converters).
By: Dr. Shahram Javadi71
AC to DC Converter
Type of input: AC supply (fixed voltage & frequency)
Type of output: DC voltage (variable)
Line
CommutatedConverter
+
-
DC Output
V0(QC)
AC
Input
Voltage
By: Dr. Shahram Javadi72
Single Phase Diode Rectifier Circuit
By: Dr. Shahram Javadi73
Single Phase Ac-Dc Converter
By: Dr. Shahram Javadi74
Applications
Speed control of DC motor in DC drives.
UPS.
HVDC transmission.
Battery Chargers.
By: Dr. Shahram Javadi75
AC Voltage Regulators
AC
VoltageController
V0(RMS)
fS
Variable AC
RMS O/P Voltage
AC
Input
Voltage
fs
Vs
fs
Type of input: AC supply (fixed voltage & frequency).
Type of output: Variable AC RMS O/P voltage.
By: Dr. Shahram Javadi76
Single Phase Ac-Ac Converter
By: Dr. Shahram Javadi77
Applications
Speed control of ac motors.
Speed control of fans (domestic and industrial fans).
AC pumps.
By: Dr. Shahram Javadi78
Cyclo Converters
Cyclo
Converters
V , f0 0
f < f0 S
Variable Frequency
AC Output
Vs
fs
ACInput
Voltage
Type of input: AC supply (fixed voltage & frequency).
Type of output: Variable frequency ac O/P voltage.
By: Dr. Shahram Javadi79
Applications
Traction vehicles
Gearless rotary kilns.
By: Dr. Shahram Javadi80
DC Choppers
DC
Chopper
V0(dc)
-
Variable DC
Output VoltageVs
+
+
-
Type of input: Fixed DC supply voltage.
Type of output: Variable DC voltage.
By: Dr. Shahram Javadi81
Dc-Dc Converter
By: Dr. Shahram Javadi82
Applications
Speed control of DC motors from a DC supply.
DC drives for sub-urban traction.
Switching power supplies.
By: Dr. Shahram Javadi83
Inverters
Inverter
(ForcedCommutation)
AC
Output Voltage
+
-
DC
Supply
Type of input: Fixed DC supply voltage.
Type of output: AC O/P voltage.
By: Dr. Shahram Javadi84
Single Phase Dc-Ac Converter
By: Dr. Shahram Javadi85
Applications
Industrial AC drives using induction and synchronous motors.
Uninterrupted power supplies (UPS system) used for computers, computer labs.
By: Dr. Shahram Javadi86
Peripheral Effects
By: Dr. Shahram Javadi87
Induced current and voltage harmonic into supply system, and at the output of the converters.
Distortion in the output voltage.
Unwanted electromagnetic radiation.
Interference with communication circuits.
Peripheral Effects