Functionarea IGCT Si IGBT

Power Electronics LabAll rights reserved.Prof. Bernet 9/2003-1

Steffen BernetBerlin University of Technology

Power Electronics LabBerlin, Germany

Function, Technology and Features of IGCTs and High Voltage IGBTs


Outline1. Introduction

2. Structure, Function and Characteristics of IGBTs

3. Structure, Function and Characteristics of IGCTs

4. Latest IGCT Technology Developments

IGCT Series Connection

10kV IGCTs

5. Conclusions


Power Semiconductors

Press-PackPress-Pack

1836

4500V; 4000A 6000V; 6000A

MITSUBISHI

Press-PackPress-Pack

15.7512.65

4500V; 3500A5500V; 2300A

ABBIGCTIPM6.754500V; 1500AABB

Press-Pack3.963300V; 1200ATOSHIBAModule3.963300V; 1200A HITACHI

Module3.963300V; 1200A4500V

MITSUBISHI

ModuleModule

3.963.6

3300V; 1200A, 6500V; 600A

EUPECIGBTPress-Pack184500V; 4000A ABBPress-Pack366000V; 6000A HITACHIPress-Pack366000V; 6000A MITSUBISHIGTO

CaseSwitchPower(MVA)

RatingsCompanyPower Semiconductor

Power Semiconductors for MV Converters


Advantages:1. High on-state current density2. High blocking voltage and switch power3. High off-state dv/dt withstand capability4. Integration of inverse diode on the same

silicon wafer5. Small part count in the reliable press-

pack case

Characteristics of Conventional GTOs


Udc

Turn-off Waveforms of GTOs

Characteristics

Typical Turn-off Gain:IT/IRG = 3 5

dv/dt = (500-1000) V/s


Gate

Unit

20 V

ShrinkingPlasma

Turn- off Behaviour of GTOs


Disadvantages:1. Inhomogeneous turn-off transient2. Limitation of dv/dt to about 500-

1000V/s3. Bulky and expensive snubber circuits4. Complex gate drive5. High gate drive power

Characteristics of Conventional GTOs


Structure of a NPT - IGBT Chip


Conduction State of a NPT - IGBT

B A

p+

BA Gate Emitter

SiO2

p+

Al

n+

p-

Emitter

p+

n-p+n-

-

-

-

-

-

--

--

--

--

-Collector

p-d

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

++

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

2 3 1 1 3 2


Silicon Chip 220 mSolder 80 m

Chip 1 Chip n. . . Aluminium oxide - Isolation 380 mUpper & lower copper layer 300 mSolder 80 mBaseplate(Copper) 3 mmThermal compound 50 mHeatsink

Structure of an IGBT Module


Hard Turn on Transient of an IGBT Module

(FZ1200R33KF1 (3300V; 1200A), Vdc=2250V, Io=1050A, Tj=25C)

-2 0 2 4 6 8 10 12 14 s 18

2.5

2.0

1.5

1.0

0.5

0

2.0

kA

1.0

0

VCE[kV]

IC[kA]


Hard Turn off Transient of an IGBT Module

(FZ1200R33KF1 (3300V; 1200A), Vdc=2250V, Io=1050A, Tj=25C)

-2 0 2 4 6 8 10 12 14 s 18

1.2

0.8

0.4

0

3.0

2.0

1.0

0

IC[kA]

VCE[kV]


Protection: Limitation of short circuit current by

IGBT (e.g. VGE=15V; IC=3*Ir ) Turn off transient within 10s Short Circuit Safe Operating Area:

Vdcmax=2500V; ICmax=3.5*Ir Failure: Heavy destruction of IGBT by

overcurrent Mostly open circuit after destruction

Characteristics of High Power IGBT Modules


Reliability: Aluminum wires and bonds are critical

parts at power cycling tests Increase of thermal resistance by

migration of thermal contact grease and inhomogeneous thermal contacts

Characteristics of High Power IGBT Modules


Very low gate drivepower (e.g. 3-5 W)

Control of dv/dt and di/dt

Active overvoltageprotection activeclamping (e.g. forseries connection)

Active short circuitprotection

Characteristics of IGBT Gate Units


Advantages1. Full insulation of base plate (simple cooling)2. Simple mounting3. Low cost plastic package

Disadvantages1. Undefined failure mode (mostly open terminals)2. Possibility of explosion3. Poor power cycling capability4. Single sided cooling

Characteristics of IGBT Modules


Physical Arrangement of an IGBT Press Pack


Advantages1. Short circuit in failure mode enables redundant

converter design (e.g. (n+1), (n+2))2. No explosion3. Double sided cooling

Disadvantages1. No insulation of heat sink2. Higher packaging costs

Characteristics of IGBT Press Packs


Physical Arrangement of IGCTs

91mm 4.5kV IGCT for water cooling51 mm 4.5kV IGCT for air cooling


Electric Field and Doping Level of 4,5 kV PT- und NPT-GTOs

0.0E+0

2.0E+4

4.0E+4

6.0E+4

8.0E+4

1.0E+5

1.2E+5

1.4E+5

12

13

14

15

16

17

18

19

20

0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0

n+ p+p n-

n+ p+p nn-

distance from cathode [m]

E(PT)

E(NPT)

NPT:

VAC = 5000 V

PT:

Log doping concentration [cm-3]

E

l

e

c

t

r

i

c

f

i

e

l

d

[

V

/

c

m

]

UAC = 5000 V

Comparison of PT and NPT Structure


IGCT Turn-off Waveforms

4

1

Ia (kA)Vdm

Tj = 90C

Itgq

4

3

2

1

0

-10

-20

Vg (V)

2

3

0

anode - voltage Vd

anode - current Ia

gate voltage Vg

thyristor transistorx

Vd (kV)

2015 3025 35 t!!m!s)


Protection: Active turn-off transient for Ishort (t)


Storage time: ts-IGCT=1/15*ts-GTO Despite of increase of Igqrm:

Qg-IGCT=0.4*Qg-GTO Transparent anode : On-state gate

current of IGCT is reduced by 50% IGCT gate drive power is reduced by

50% Uncritical minimum switching times do

not require control on IGCT gate drive

Characteristics of an IGCT- Gate Drive in Comparison to a GTO Gate Drive


Reliability: Low part count and press-pack case

enable high reliability Qualification tests and field eperience:

FIT(Failure in one billionhours)


Turn-off Transient of an IGCT Inverse Diode

-1500

-750

0

750

1500

2250

A

-4

-2

0

2

4

6

kV

0 5 10 15 20

s

(4500V; 1560A - RCIGCT; VDC=2800V, IF=1300A; VDM=4335A;

di/dt=400A/s)


Motivation of Research- General Development Trend

Increasing importance of PWM-VSIs- Replacement of Cycloconverter and LCI- Increasing use in energy systems (e.g. Windparks, HVDC,

STATCOMs, Active Filters, High Power UPS) Increase of converter voltage and power

- Converter voltage of Vout,RMS = 6 kV 10 kV - Series Connection of IGCTs

(e.g. n=3 devices per switch position in 3L-NPC VSI)- Increase of device voltage at useful silicon utilization

(e.g. 10kV IGCT / diode: Vout,RMS =6 kV 7.2 kV in 3L-NPC VSI)


Voltage definitions

VDRM

VDC NOM(continuous @ TJmax)

VDC MAX( 15 seconds @ TJmax)

100 s

10 ms


Device Voltage Ratings in 3-Level Inverter (N =1)

Nominal RMS Line Voltage

Nominal DC Half- Link Voltage

15% Vll,, 100 FIT and long-term DC

stability

Maximum DC Half Link Voltage

33% Vll, , SOA and short-term

DC stability

Maximum Repetitive

Blocking Voltage

VRMS (kV) VDC NOM (kV) VDCMAX (kV) VDRM (kV) 2.3 1.9 2.2 3.3 3.3 2.7 3.1 4.5

4.16 3.4 3.9 5.5 6 4.9 5.6 8

6.6 5.4 6.2 9 6.9 5.6 6.5 9.5 7.2 5.9 6.8 10


Number N of Series Connected Devices in 3L NPC VSI

Nominal RMS Line Voltage

N of 4.5 kV IGCTs / Diodes

N of 5.5 kV IGCTs / Diodes

N of 10 kV IGCTs / Diodes

VRMS (kV) 2.3 1 - - 3.3 1 - -

4.16 - 1 - 6 2 - 1

6.6 3 2 1 6.9 3 2 1 7.2 3 2 1


IGCT - Series ConnectionReasons for Voltage Unbalance of Series Connected DevicesStatic Deviating leakage currents

Dynamic Delay between Gate Signals Deviating switching behavior (e.g.)

Different tail or reverse recovery charges Different switching times (dv/dts, di/dts)

Consider The IGCT has a latching thyristor structure ! Control of dv/dt or clamping of switch voltage by gate control in active region is not possible in contrast to the IGBT or MOSFET ! External balancing 2-Pole required !

Bal.

2-Pole

Bal. 2-Pole

Bal. 2-Pole


Balancing Circuit

Dynamic voltage balancing: RC-Snubber Static voltage balancing: balancing resistor

RpRSnub

CSnub

Design Tradeoffs: low losses CSnub good balancing CSnub , selected IGCTs


Design Criteria

avoid Vmax > 4.5kV (immediate device destruction)

t

VGCT

switching transients

average blocking voltage lower than 2.8kV (FIT)

4.5kV

2.8kV

Values given for 4.5kV IGCTs

Blockingms


snubberresistor

snubbercapacitor

currentsensor

IGCT - Series Connection (RC - Snubber)Test Setup Buck Converter

VDC=6 kV, Iout=4 kA n=2

91mm 4.5kV IGCTs 68mm 4.5kV diodes

Snubber Rsnub=1 Csnub= 500 nF Rp=25 k

Rp

Rsnub

Csnub


0

1

2

3

100 101 102 103 104 105

IGCT 1IGCT 2

current

voltage

time (s)

I

G

C

T

v

o

l

t

a

g

e

,

I

G

C

T

c

u

r

r

e

n

t

(

k

V

,

k

A

)

VDC=4.6kV; Iout=2kA; n=2; Tj=115C; Csnub=500nF; Rsnub=1

IGCT Series Connection - Turn-off Transient


1.6

0

2

4

6

8

10

with snubbersnubberless 8.5

6.4

9.28

Etotal

0.630

0.650

0.5

8

Eon,SnubberEoff,SnubberEon, IGCTEoff, IGCT

L

o

s

s

e

s

(

J

)

LossesVDC = 4.5 kV, Iout = 2 kA


Technical Data Phase Leg / 3~ Inverter

Parameter Value / Typenominal dc input voltage VDC = 13.2 kV (10%)rms output current Iout = 1.5 kAnominal peak output current Iout, peak = 2.5 kAoutput power Sout = 8 MVA / 24 MVAcarrier frequency fs = 700 HzIGCT 5SHY35L4503 (4.5kV 91mm)diode (4.5kV 68mm) D65S45 (4.5kV 68mm)


IGCT Series Connection - Output Waveforms

14.2kV

V4

VoutIout

VDC=14.2kV; Iout,rms=1.5kA;fs=700Hz; fout=50Hz

-10

-5

0

5

10

0 5 10 15 20-2

-1

0

1

2

Vout Iout

Time / ms


IGCT Series Connection - Test Setup

0,9m

DC-LinkCapacitorsDC-LinkCapacitors

LoadInductorLoadInductor

IGCT-StackIGCT-Stack

RC-SnubberRC-Snubber

Photo Phase Leg


Trade-off Curves of 5.5 kV and 10 kV IGCTs Similar losses of ideal series connection of 5.5 kV IGCTs and 10 kV IGCTs

Additional snubber losses in real series connection (e.g.)

Static: PR (Rp=25 k) Dynamic: Esnub,C 0.15 Eoff,IGCT

(4.5 kV IGCTs / N=2 @VDC=4500V, Ilout=2 kA)

J=20A/cm2


Compared to an IGCT series connection (N=2)10 kV IGCTs / diodes feature: Comparable losses for fs=200 Hz-1 kHz Reduction of part count

- by 71% (S 5.5 MVA)- by 41% (S > 5.5 MVA)

Increase of reliability- by 56% (S 5.5 MVA)- by 12% (S > 5.5 MVA)

Simpler stack design Avoidance of RC snubber

Simpler maintenance Avoidance of semiconductor selection and RC snubber

Potential of 10 kV IGCTs and Diodes


Design of 10 kV IGCTs

Cathode

1050 m

n+ Cathodep Base

n Basen BufferLayer

Low Efficiency

p - Anode

GateAnode

Manufacturing process in line with standard IGCT / GTO process Double diffused p-base Heavily doped cathode emitter Buffer layer for field stopping Low efficiency p Anode

Cosmic ray withstand capability: 2 FIT / cm2

n-base thickness: 1050 m Substrate doping level: 4.2 1012 cm-3

Silicon resistivity: 1000 cm


Engineering Sample of 68 mm 10 kV IGCT


Forward Blocking Characteristics at 25C

(


Forward Blocking Characteristics at 125C

(


On-state Characteristics

(4.5V @ 1 kA, 125C)VT = VT0 + rdIAVT0 (Threshold voltage): 3.5VRd (On-state resistance):1m


Test circuit and stack design (VDC=2.4kV-7kV, IA=100A-1kA, Tj=25C-115C, Lcl=13.6H, Ccl=1F, Rcl=2.3 )

Turn-off Characteristics

1R

0,68uF27k

1R

0,68uF27k

1R

0,68uF27k

1R

0,68uF27k

Cbat

Lh

R

D

DUT

D

C

L


Turn-off Waveforms

Switching characteristics:VDC=5.7 kV, IA=900 A,Tj=85C: Eoff=11 Ws, tf=1 s, ttail=6 s, VAK,max=6.7 kV


Turn-off WaveformsVAK [V] 1kV / div IA [A] 100A / div

Time [s] 5s / div Time [s] 5s / divOperating conditions:VDC=2.5kV 5.7kV, IA=800A 900A, Tj=85CSwitching characteristics:VDC=5.7kV, IA=900A: Eoff=11 Ws, VAK,max=6.6kV, tf=1s, ttail=6s


Turn-off Waveforms (SOAR)

Operating conditions:VDC=7kV, IA=1000A, Tj=85CSwitching characteristics:Eoff=14.8 J, VAK,max=8 kV, toff=8s, tf=1s, ttail=5s

World Record !


T = 1ms10 kA ITSM

-125C TJ MAX

-13 K/kWRth J-C

IA = 1000 A, VDC = 6 kV 11 WsEOFF

VDC = 6 kV1000 AITGQ

1 kA (rd = 1 m, VTO = 3.5 V)

4.5 V VTM

-22 V VGR

for 100 FIT, 100 % DC6 kVVDC

Tj = 0 - 125 C10 kVVDRM

ConditionsElectrical and thermal characteristics

Specification of 68mm 10kV IGCTs


IGBTs and IGCTs replace GTOs in MV Converters Advantages of IGBTs

IGBT MOS-controlled device Low power GU GU control of dv/dt and di/dt Short circuit current limitation and active turn off Active clamping

Simple mechanics Simple scalability

Conclusions


Disadvantages of IGBTs Higher losses and poorer Si-utilization than IGCTs Limited power cycling capability of IGBT modules Costs (especially of IGBT press packs)

Development trends Reduction of losses and costs by new technologies and high volume production

Conclusions


1. Traction Converters (LSC, MSC)

2. Energy Systems (e.g. HVDC, SVC)

3. Industrial Medium Voltage Drives

Applications of HV - IGBTs


ConclusionsAdvantages of IGCTs

Maximum Silicon Utilization Low costs / MVA Small Part Count + Press pack

High Reliability + Explosion Free Inverters Low On-state and Total Losses

High Efficiency and Power Density 4.5 kV / 5.5 kV IGCT product family

300 kVA-10 MVA Inverters without Series or Parallel Connection


Conclusions

Disadvantages of IGCTs Shoot through protection

High mechanical stress for IM / SM

Thyristor structure No dv/dt or di/dt control ClampLarger gate drive power and size


Development trends IGCT: Mature device Increase of device voltage (e.g. 10kV IGCT) Increase of Tjmax (e.g Tjmax=175C). Low cost, efficient series connection

Conclusions


1. Industrial Medium Voltage Drives

2. Energy Systems- Railway Interties- Power Quality Products

- e.g. Dynamic Voltage Restorer- Wind Energy Systems

Applications of IGCTs

Functionarea IGCT Si IGBT

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