COMPARISION OF POWER COMPARISION OF POWER ELECTRONIC DEVICESELECTRONIC DEVICES

BYBYSANGEETHA.VSANGEETHA.V

CONTENTS• Classification of devices• Structure• Characteristics• Safe operating area• Advantages and Disadvantages• Applications

CLASSIFICATION OF POWER ELECTRONIC CLASSIFICATION OF POWER ELECTRONIC DEVICES :DEVICES :

Uncontrollable Device:DiodeUncontrollable Device:Diode

Half-Controlled Device:ThyristorHalf-Controlled Device:Thyristor

Fully Controlled Fully Controlled Device:MOSFET,IGBT,GTODevice:MOSFET,IGBT,GTO

STRUCTURESTRUCTUREDIODEDIODE BJTBJT

STRUCTURESTRUCTUREMOSFETMOSFET IGBTIGBT

STRUCTURESTRUCTURETHYRISTOR

GTO

STRUCTURESTRUCTURE

RCTRCT MCTMCT

CHARACTERISTICSCHARACTERISTICSBJTBJTDIODEDIODE

CHARACTERISTICSCHARACTERISTICSMOSFETMOSFET IGBTIGBT

CHARACTERISTICSCHARACTERISTICS THYRISTORTHYRISTOR

Reverse breakdown voltage

Holding current

Reverse leakage current

Latching current

Forward volt-drop(conducting)

Forward break-over voltage

Forward leakage current

Gatetriggered

IH

IL

VBO

VAK

IT

CHARACTERISTICSCHARACTERISTICSMCTMCT

SAFE OPERATING AREASSAFE OPERATING AREAS

Forward BiasForward Bias Reverse BiasReverse BiasBJT:

SAFE OPERATING AREASSAFE OPERATING AREAS MOSFET:MOSFET:• Three factors Three factors

detemine the SOA of detemine the SOA of the the MOSFET:maximum MOSFET:maximum drain current (Idrain current (IDMDM)), , internal junction internal junction temperature (Tj) and temperature (Tj) and the breakdown the breakdown voltage.voltage.

IGBT:

Safe operating area (SOA) is defined as the voltage and current conditions over which the device can be expected to operate without self-damage.

SAFE OPERATING AREASSAFE OPERATING AREAS

IGBTIGBT

• GTO:

SAFE OPERATING AREASSAFE OPERATING AREAS MCT:MCT:• Safe Operating Area is limited Safe Operating Area is limited

by the maximum controllable by the maximum controllable anode current , maximum anode current , maximum power dissipation and power dissipation and temperature.temperature.

• As the anode-cathode voltage As the anode-cathode voltage increasesincreases,,maximum current maximum current starts decreasing due to starts decreasing due to powerpower d dissipatioissipationn and internal and internal device avalanche mechanism.device avalanche mechanism.

• Since the 50A is large Since the 50A is large enough , the snubber less enough , the snubber less operation is possible.operation is possible.

ADVANTAGES Diode:• No filament is necessary.• Occupies lesser space.• Long life.

BJT:• Low cost than any other semiconductor

transistors.• Less complexity in fabrication.• It is a simple process.

• MOSFET:

• Mosfet are small compare to bjt's so it fabricated easily and space saving scheme on the ic's

• Mosfet's input impedance are very high so they do not load the circuits. So loading effect doesn't arise.

• Operating frequency is very high so may be used at higher frequencies.

• Used in digital circuits for it's reliability. • Effect of noise is less than bjt. so high signal to

noise ratio. • Mosfets are unipolar devices so reverse saturation

current doesn't exist. • It consume less D.C power rather than BJT.

IGBT:

• It has a very low on-state voltage drop due to conductivity modulation and has superior on-state current density. So smaller chip size is possible and thus cost can be reduced

• Low driving power and a simple drive circuit due to the input MOS gate structure; it can be easily controlled as compared to current-controlled devices (thyristors , BJTs) in high voltage and high current applications

THYRISTOR:• Simple turn on device• low cost• High voltage and current capability.

GTO:• Low conduction losses.• Low cost.

MCT:• Low forward conduction drop.• Fast turn on and turn off time.• Low switching losses• High gate input impedance. RCT: These devices are advantageous where a reverse or

freewheel diode must be used. Because the SCR and diode never conduct at the same time they do not produce heat simultaneously and can easily be integrated and cooled together.

APPLICATIONSAPPLICATIONSDIODE:DIODE:• As rectifier to convert Ac into Dc.As rectifier to convert Ac into Dc.• As an switch in computer circuits.As an switch in computer circuits.• As detectors in radios to detect audio signals.As detectors in radios to detect audio signals.• As LED to emit different colours.As LED to emit different colours.BJT:BJT:• It is used as a switch.It is used as a switch.• It is used as a amplifier.It is used as a amplifier.

APPLICATIONSAPPLICATIONSMOSFETMOSFET• Used in digital integrated circuits.Used in digital integrated circuits.• Radio systems use MOSFETs as oscillator or Radio systems use MOSFETs as oscillator or

mixers to convert frequencies.mixers to convert frequencies.• Used in audio frequency power amplifiers for Used in audio frequency power amplifiers for

public address systems.public address systems.IGBTIGBT• It is used in PWM,UPS,SMPS and other power It is used in PWM,UPS,SMPS and other power

electronic circuitselectronic circuits..• It is used for medium power applications.It is used for medium power applications.

APPLICATIONSAPPLICATIONSTHYRISTOR:THYRISTOR:• Mainly used where high currents and voltages are Mainly used where high currents and voltages are

involved, and are often used to control alternating involved, and are often used to control alternating currents, where the change of polarity of the current currents, where the change of polarity of the current causes the device to switch off automatically; causes the device to switch off automatically; referred to as Zero Cross operation.referred to as Zero Cross operation.

• Thyristors can be used as the control elements for Thyristors can be used as the control elements for phase angle triggered controllers, also known as phase angle triggered controllers, also known as phase fired controllers.phase fired controllers.

GTO:GTO:• HVDC Systems.HVDC Systems.• Applications with low switching frequencies.Applications with low switching frequencies.

APPLICATIONSAPPLICATIONSMCT:MCT:• UPS.UPS.• Static VAR regulators.Static VAR regulators.• Harmonic compensators.Harmonic compensators.• AC Motor Drives.AC Motor Drives.

RCT:RCT:• RCT’s (reverse conducting Thyristors) is widely RCT’s (reverse conducting Thyristors) is widely

used for high speed switching especially in traction used for high speed switching especially in traction applications. applications.

• Reverse conducting thyristors are often used in Reverse conducting thyristors are often used in frequency changers and inverters.frequency changers and inverters.

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