(1) advancements in power elec

8/2/2019 (1) Advancements in Power Elec

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POWER ELECTRONICS

INTRODUCTION TO

POWER ELECTRONICS

Dr M R Abro


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POWER ELECTRONICS

ELECTRONICS

COTROLPOWER


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Power Electronics

Definition:It involves the study of electronic circuits intended to

control the flow of electrical energy. The circuits handle

power flow at levels much higher than the individual

device ratings. (M. H. Rashid, Hand BookP#1)

OR

It is defined as to control & convert electrical power by

the application of converter topologies incorporating the

matrix of switching devices under the guidance of control

electronics.


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History of Power Electronics: It began with the introduction of mercury arc rectifier in

1900

Then metal tank rectifier, grid controlled vacuum tuberectifier, ignitron, phanotron & thyratron were introducedgradually and these devices were applied for power controluntil 1950s

The first electronics revolution began in 1948 with the

invention of silicon transistor at Bell TelephoneLaboratories

PNPN triggering transistor, which was letter called as athyristor or silicon controlled rectifier, was invented by BellTelephone Laboratories in 1956

The second electronics revolution began with thedevelopment of the commercial thyristor by the GeneralElectric Company & thus the new era of Power Electronicsbegan. Since then, many different types of semiconductordevices and conversion techniques have been introduced


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Power Electronics as a Multi Disciplinary Technology

PowerElectronics

PowerSemiconductor

Devices

ConverterCircuits

ControlTheory

MicroComputers

VLSI Circuits

Computer AidedDesign Techniques

SignalProcessing

ElectricalMachines


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Recent Advances in Power Electronics

SemiconductorDevices

ConverterCircuits

Control ofPower

Electronics


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Four generations of Solid-State Power- Electronics

First generation (1958-1975) (Thyristor Era)

Diode

Thyristor

TRIAC

Second Generation (1975-1985)

Power BJT

Power MOSFET

GTO

Microprocessor

ASIC

PIC

Advance Control


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Four generations of Solid-State Power- Electronics

Third generation (1985-1995)

IGBT

SIT

SITH

MCT

IPM (intelligent Power Module)

DSPs

Fourth Generation (1995-)

IGCT

Cool MOS

PEBB (Power Electronics Building Block)

Sensorless Vector Control

Al Techniques: Fuzzy logic, Neural Networks, GeneticAlgorithms.


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Classification of Semiconductor Devices

Semiconductor devices can be classified into three categoriesaccording to their degree of controllability:

Un-controlled turn-on and off devices (e.g. Diodes).

Controlled turn-on and uncontrolled turn-off (e.g. SCR).

Controlled turn-on and off (e.g. BJT, SITH, MOSFET, GTO,

IGBT, SIT,MCT).


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Different Features of

Semiconductor Devices

Devices which requires continuous

signal for keeping them in turn-on

state

BJT, MOSFET, IGBT and SIT

Devices which requires pulse-gatesignal for turning them on & once

these devices are on then gate

pulse is removed

SCR, GTO, SITH and MCT

Devices which posses bidirectional

current capabilityTRIAC and RCT

Devices which posses

unidirectional current capability

Diode, SCR, GTO, BJT, MOSFET,

IGBT, SIT, SITH, MCT


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CLASSIFICATION OF SEMICONDUCTOR DEVICES

Thristors

Line Commutated

ForcedCommutated

TRIAC

GTO IGCT

MCT

LASCR

GATT

RCT ETO

MTO

Schottky

Fast Recovery

General Purpose

Power Semiconductor

Devices

Power Diodes Power Transistors

Power BJTs

Power MOSFET

IGBT

SIT

SITH


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POWER DIODES

GENERAL PURPOSE DIODE:

Voltage/Current Ratings: 10KV/5KA Switching Time (S): 25

On Voltage/Current: 1.6V/10KA

Are generally manufactured by diffusion

High reverse recovery time Use in low speed applications where recovery time is not

critical

FAST RECOVERY DIODE:Voltage/Current Ratings: 3000V/1000A Switching Time (S): 2-5

On Voltage/Current: 3V/3KA

Low recovery time

Use in choppers & inverters where the speed of recovery time is ofcritical importance


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POWER DIODES

SCHOTTKY DIODE:Voltage/Current Ratings: 100V/300A Switching Time (S): 0.23

On Voltage/Current: 0.58V/60A

Have low on state voltage

Very small recovery time (typical of nanoseconds)

The leakage current increases with the voltage ratings &their ratings are limited to 100V

These are ideal for high current & low power voltage dc

chopper supplies

Anode

Semiconductor

Cathode

Metal


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POWER TRANSISTORS

Power BJT:Voltage/Current Rating: 1200V/800A It is a current controlled bi-polar two junction device. Switching speed is considerably faster than that of thyristor-

type devices. Fall into obsolescence due to advent of IGBT.

Power MOSFET:Voltage/Current Rating: 600V/400A It is unipolar & voltage controlled device It is faster of all the devices It can operate in hundreds of KHz switching frequency It is commonly used in high frequency switching mode power

supplies It is not used in high power converters because of large

conduction losses


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POWER TRANSISTORS

IGBT:

Voltage/Current Rating: 3500V/1200A

It is basically a hybrid MOS-gated turn-off bipolartransistor

It combines the attributes of MOSFET,BJT & thyristor

It was commercially introduced in 1983

It is faster than that of BJT

It can operate in medium power upto 20KHz switching

frequency It is finding popularity & has replaced BJT.


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POWER TRANSISTORS

IGBT (Continued):

The invention of IGBT is an important milestone in the history of Power Semiconductor

devices. 6.5KV & 10KV devices are under test in

laboratory.

IGBT Intelligent Power Module (IPM): This device is available for 6000V, 50-300A &

1200V, 50-150A to cover up to 150hp ac driveapplications.


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POWER TRANSISTOR

SIT:

Voltage/Current Rating: 1200V/10ASwitching Time (S): 0.55

It is high power high frequency device

It is solid state version of a triode vacuumtube

It was commercially introduced by TOKIN

Corp in 1987

It is used in AM/FM transmitters, inductionheating, high voltage low current powersupplies


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THYRISTORS

Line or Natural Commutated Thyristors:Voltage/Current Ratings: 8000V/4500A

Switching Time (S): 10 to 20 in a 3000V, 3600A Thyristor

These are turned off due to the sinusoidal nature of input voltage

Forced Commutated Thyristors:These are turned off by an extra circuit called commutation circuitry

TRIAC:Voltage/Current Ratings: 1200V/300A


Its characteristics are similar to two thyristors connected inparallel & having only one gate terminal

The current flow through it can be controlled in either direction These are widely used in all types of simple heat controls, light

controls, motor controls & AC switches


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THYRISTORS

GTO:

Voltage/Current Ratings: 6000V/6000A (Mitsubishi) .

Switching Time (S): 25


It is self turned off thyristor. It does not require any commutation circuit.

It is used for commutation converters.

RCT:

Voltage/Current Ratings: 2500V/1000A Switching Time (S)


It is connected as a thyristor with an inverse parallel diode

These are used for high speed switching (traction applications)


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Thyristors

SITH:Voltage/Current Ratings: 4000V/2200A Switching Time (S): 6.5


It is self controlled GTO like device

It was commercially introduced by TOYO Co. in 1988 These are applied for medium power converters with

frequency of several hundreds of kilo hertz beyond thefrequency of GTO

GATT:Voltage/Current Ratings: 1200V/400A Switching Time (S): 8

On Voltage/Current: 2.8V/1.25KA

These are used for high speed switching, specially intraction applications


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Thyristors

LASCR:Voltage/Current Ratings: 600V/1500A Switching Time (S): 200-400On Voltage/Current: 2.4V/4.5A

These are suitable for high voltage system applications, specially inHVDC systems

The four layer PNPN construction is similar to that of ordinary SCR withone exception- the PN junctions are formed on a silicon pellet in anelongated manner to permit radiations by a light source

MCT:Voltage/Current Ratings: 4500V/250A, 900V/15A, 1000V/30A, 600V/60A

It is a thyristor like trigger into conduction device that can be turned onor off by a short pulse on the MOS gate

This was introduced by General Electrical Company in November 1988 It is like a GTO, except that the turn-off gain is very high


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Thyristor

IGCT:

Available with 6000V, 6000A (10KV devices are under test)

It integrates a gate-commutated thyristor (GCT) with a

multilayered printed circuit board gate drive The GCT is a hard-switched GTO with a very fast & large gate

current pulse, as large as the full rated current, that draws out allthe current from cathode into the gate in about 1S to ensure afast turn-off

Similar to GTO, the IGCT is turned on by applying the turn-on

current to its gate The IGCT is turned off by a multilayered gate driver circuit board

that can supply a fast rising turn-off pulse (i.e., a gate current of4KA/S with a gate cathode voltage of 20V only)


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Thyristor

Reverse Blocking IGCT :Available with 6000V, 800A is introduced very recentlyby ABB for use in IFI drives.

ETO: It is a MOS-GTO hybrid device that combines the

advantages of both the GTO & MOSFET ETOs with current rating of up to 4KA & voltage rating

of up to 6KV have been demonstrated It is suitable for high power and high frequency

applications


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Thyristor

MTO:

It is a combination of a GTO & a MOSFET, which together

overcome the limitations of the GTO turn-off ability

Its structure is similar to that of a GTO and retains theadvantages of high voltage (up to 10KV) & high current (up to4000A)

Can be used in high power application ranging from 1 to 20MVA


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MONOLITHIC INTEGRATION OF POWER, CONTROL ANDPROTECTION ELEMENTS SMART POWER

ADVANTAGES OF COST, SIZE, EMI PROBLEM ANDRELIABILITY

ISOLATION PROBLEM OF LOW AND HIGH VOLTAGE

DEVICES

THERMAL MANAGEMENT PROBLEM

EXAMPLE COMMERCIAL PICs:

STEPPER MOTOR DRIVEBRUSHLESS DC MOTOR (BLDM) DRIVEH-BRIDGE INVERTERCHOPPER FOR DC MOTOR DRIVEGATE DRIVER FOR IGBT

DC-DC CONVERTER

POWER INTEGRATED CIRCUIT(PIC) FEATURES


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Power Integrated Circuit for DCMotor Drive


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Relative properties of Controllable Switches


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SWITCHING FREQUENCY (Hz)

DEVICE

V-IRATING

S

PRODUCT(VI)

10 !02 103 104 105 10610

102

103

104

105

106

107

108

TRIAC

THYRISTOR

IGBTDISCRETE

IGCT

GTO

IGBT IPM

POWERMOSFET

Power FrequencyTrends of the Devices


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Types of Power Electronic Circuits:

For the control of electric power the conversionof electric power from one form to another isnecessary and the switching characteristics ofthe power devices permits these conversions.The static power converters performs thesesfunctions of power conversions. A converter

may be considered as a switching matrix. Thepower electronics circuits can be classified intothe following types:

Diode rectifiers

AC-DC converters (controlled rectifiers)

AC-AC converters (AC voltage controllers)

DC-DC converters (DC choppers)

DC-AC converters (inverters)

Static switches

F b i t f t d di th


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Four basic types of converters depending upon thefunction performed


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Control of Power Electronics

Neural Networks

Expert & Fuzzy

Control

MicrocomputerControl

VLSI Control


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SOME SIMULATION PROGRAMS

MATLAB/SIMULINK PSPICE PSIM EMTP MATRIXX SIMNON SABER C


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Digital Controller ClassificationIn a VLSI, a very large number of devices areintegrated monolithically in a chip to providegreat simplification of hardware. A VLSI chipmay use digital, analog, or mixed signals.

The instruction set is complex,which results in a complexarchitecture & a sluggishcomputation.

Reduced instructionset computers: Simplearchitecture allows forhigh speeds

Speciallydesignedfor highspeedparallelprocessin

g usingseveralprocessors

A custom chip (notprogrammable) is very

economical & is designed forspecific applications. An ASIC

chip can be designed withdigital, analog, memory

elements (ROM, RAM), & RISCor DSP to satisfy full control

function.

Interconnected functionalcircuits such as (D flip-flop,counters, etc) to providemore efficient performance& effective chip estate

utilization than gate arrays.

The gate arrayconsists of a matrix of

simple logic gates thatare interconnected bythe user in a fieldprogrammable GA

(FPGA) orprogrammable logicdevice (PLD), whichcan be programmed

electrically (ELPD) orby mask (CPLD)

similar to EPROM or

PROM, respectively.


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Applications DC AND AC REGULATED POWER SUPPLIES

MOTOR DRIVES

INDUCTION HEATING

SOLID STATE CIRCUIT BREAKER

VARIABLE SPEED CONSTANT FREQUENCY SYSTEM

PHOTOVOLTAIC AND FUEL CELL CONVERSION

HIGH VOLTAGE DC SYSTEM

POWER LINE VAR AND HARMONIC COMPENSATION

ELECTRONIC WELDING

HEATING AND LIGHTING CONTROL

ELECTRO CHEMICAL PROCESSES

POWERELECTRONIC

SYSTEMS

Flexible AC Transmission System, FACTS


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Applications

A 3-phase controlled bridge circuit used as a basic topologyfor many converter systems


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Applications

A high voltage DC (HVDC) transmission system


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Applications

Parallel connection of two 6-pulse converters


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Applications

Variable frequency converter for motor control


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Pulse width modulated or square wave inverter with a controlledrectifier input

Applications


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Applications

Current-source inverter on the output section of motor drive systemusing capacitors for power factor correction


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Applications

Per phase thyristor-controlled inductor (TCI) &thyristor-switched capacitor (TSC) system


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Applications

Static transfer switch used in a UPS system


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POWER ELECTRONICS IN ENERGY SAVING

CONTROL OF POWER BY ELECTRONIC SWITCHING IS MOREEFFICIENT THAN OLD RHEOSTATIC CONTROL

ROUGHLY 60% - 65% OF GENERATED ENERGY IS CONSUMED INELECTRICAL MACHINESMAINLY PUMPS AND FANS

VARIABLE SPEED operation of the motor with the help ofPower Electonics is highly efficient.

20% OF GENERATED ENERGY IS USED IN LIGHTING HIGH FREQUENCY FLUORESCENT LAMPS ARE 2-3 TIMES MORE

EFFICIENT THAN INCANDESCENT LAMPS


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HOW TO SOLVE OR MITIGATE ENVIRONMENTAL PROBLEMS

WITH THE RELEVANCE OF POWER ELECTRONICS?

PROMOTE ALL ENERGY USAGE IN ELECTRICAL FORM CENTRALIZE FOSSIL FUEL POWER GENERATION AND APPLY

ADVANCED EMISSION STANDARDS

LARGE USAGE OF RENEWABLE ENERGY SOURCES- HYDRO, WINDAND PHOTOVOLTAIC

CONSERVATION OF ENERGY BY EFFICIENT USE OF ELECTRICITY PREVENT ENERGY WASTE


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ADVANCES AND TRENDS OF POWER SEMICONDUCTOR DEVICES

MODERN POWER ELECTRONICS EVOLUTION PRIMARILY FOLLOWED THEPOWER DEVICE EVOLUTION - WHICH AGAIN FOLLOWED THEMICROELECTRONICS EVOLUTION

GRADUAL OBSOLESCENCE OF PHASE CONTROL DEVICES (THYRISTOR,TRIAC)

DOMINANCE OF INSULATED GATE CONTROLLED DEVICES (IGBT, PowerMOSFET)

POWER MOSFET WILL REMAIN UNIVERSAL IN LOW VOLTAGE HIGHFREQUENCY APPLICATIONS

GRADUAL OBSOLESCENCE OF GTOs (LOWER END BY IGBTs AND HIGHEREND BY IGCTs)

REDUCTION OF CONDUCTION DROP IN HIGH VOLTAGE POWERMOSFETAND IGBT

SiC BASED DEVICES WILL BRING RENAISSANCE IN HIGH POWERELECTRONICSDIAMOND DEVICES IN THE LONG RUN


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NEXT GENERATION POWER SEMICONDUCTOR MATERIALS

SILICON CARBIDEDIAMOND

LARGE BAND GAP HIGH CARRIER MOBILITY HIGH ELECTRICAL CONDUCTIVITY HIGH THERMAL CONDUCTIVITY

RESULT

HIGH POWER CAPABILITY HIGH FREQUENCY LOW CONDUCTION DROP HIGH JUNCTION TEMPERATURE GOOD RADIATION HARDNESS


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(1) advancements in power elec

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