CONTENTS
POWER DEVICES and IGBT
2
Variation of NIEC’s IGBT Modules
4
Ratings and Characteristics
6
Power Loss and Thermal Design
10
Gate Drive
20
High Side Drive
24
3-Phase Bridge Inverter
26
Short circuit and Over-voltage Protection
30
Snubber
33
Parallel Operation
36
1
May, 2005 S.Hashizume Rev. 1.01
POWER DEVICES and IGBT
Diode is a fundamental semiconductor. Based on diode, switching characteristics of Thyristor,
Bipolar Transistor, MOSFET, and IGBT are illustrated.
DIODE
i
i
E
v
vF
Anode
i
i
Cathode
E
-E
v
vF
-E
THYRISTOR (SCR)
Anode
i
i
E
v
Gate
Cathode
E
vT
iG
Thyristor can be switched on by DC or pulse gate
current. But, it cannot be turned off by gate signal.
iG
TRANSISTOR (NPN)
Collector
E
Base
iC
iC
vCE
E
iB
vCE(sat)
Emitter
iB
Transistor can be turned on during the period when
base current is supplied.
2
POWER DEVICES and IGBT
MOSFET (Nch)
iD
iD
E
Drain
E
vDS(on)
vGS
vDS
iG
vGS
Gate
Source
iG
iD
-E
iD (=-IS)
iS
MOSFET can be turned on during the period when gate voltage is applied. Gate current
flows only for a short period at turn-on and at turn-off. Between Drain and Source, diode is
built-in on chip, and its current runs opposite to drain current.
IGBT
Collecter
iC
iC
E
Gate
Emitter
vGE
vCE
E
vCE(sat)
iG
vGE
１５V
Equivalent circuit
iG
IGBT, same as MOSFET, can be turned on during the period when
gate voltage is applied, and gate current flows also only for a short
period at turn-on and at turn-off. However, diode is not integrated on
chip. In some IGBT Modules, discrete diode are assembled in the
package.
3
VARIATION of NIEC’s IGBT Modules
PHMB
Example : PHMB400B12
Single
PDMB
Example : PDMB100B12C
Doubler, 2 in 1
PBMB
Example : PBMB100B12C
Single-phase bridge, 4 in 1
PTMB
Example : PTMB100B12C
3-phase bridge, 6 in 1
4
VARIATION of NIEC’s IGBT Module
PCHMB
Suffix –A
Example : PCHMB100B12
PRHMB(
PRHMB(--A), PRFMB
Suffix –A *1
Example : PRHMB400B12
*1 : PRFMB for 600V E-series
PVD
Example : PVD150-12
Example : PVD30-8
5
Ratings and Characteristics
For example, ratings and characteristics of PDMB100B12 are discussed here.
MAXIMUN RATINGS Tc=25℃
Item
Collector-Emitter Voltage
Gate-Emitter Voltage
Symbol
VCES
Rated Value
1200
Unit
V
VGES
±20
V
An excessive stress over these ratings may immediately damage device, or
degrade reliability. Designers should always follow these ratings.
C
Maximum collector-emitter voltage with gate-emitter shorted
G
E
C
Maximum gate-emitter voltage with collector-emitter shorted
G
E
Collector Current
Collector Power Dissipation
DC
IC
100
A
1ms
ICP
200
A
PC
500
W
Maximum DC or pulse collector current
Maximum power dissipation per IGBT element. This module (PDMB100B12)
has two IGBT elements, so this value is effective for each of two elements.
Junction Temperature
Tj
－40～ ＋150
℃
Storage Temperature
Tstg
－40～ ＋125
℃
Chip temperature range during continuous operation
Storage or transportation temperature range with no electrical load
6
Ratings and Characteristics
Isolation Voltage (Terminal to Base, AC, 1minute)
Mounting Torque
Module Base to Heatsink
VISO
2,500
V
Ftor
3 (30.6)
N・m
(kgf ・
cm)
Busbar to Main Terminal
2 (20.4)
Maximum voltage between any terminal and base, with all terminals shorted
Maximum mounting torque, using specified screws
ELECTRICAL CHARACTERISTICS Tc=25℃ (Per one IGBT）
Characteristics
Symbol
Test Condition
Min.
Typ.
Max.
Unit
Collector-Emitter Cut-off Current
ICES
VCE=1200V, VGS=0V
2.0
mA
Gate-Emitter Leakage Current
IGES
VGS=±20V, VCE=0V
1.0
µA
C
Collector leakage current, with gate-emitter shorted
G
E
C
Gate leakage current, with collector-emitter shorted
G
E
Collector-Emitter Saturation Voltage
VCE(sat)
IC=100A, VGS=15V
Gate-Emitter Threshold Voltage
VGE(th)
VCE=5V, IC=100mA
1.9
4.0
2.4
V
8.0
V
C
G
A measure of IGBT steady-state power dissipation, which refers to forward voltage of diode, onstate voltage of SCR, or on-resistance of MOSFET.
100A
15V
E
C
G
100mA
5V
Gate-emitter voltage when IGBT starts to conduct
E
7
Ratings and Characteristics
Input Capacitance
Cies
VCE=10V, VGE=0V, f=1MHz
8,300
pF
Gate-emitter capacitance, with collector-emitter shorted in AC
Switching Time
0.25
0.45
ton
0.40
0.70
Fall Time
tf
0.25
0.35
Turn-off Time
toff
0.80
1.10
Rise Time
tr
Turn-on Time
VCE=600V, RL=6Ω, RG=10Ω
VGE=±15V
µs
Definition of switching times
6Ω
C
+15V
G
－15V
600V
E
PDMB100B12 Maximum
td(on)
tr
ton
td(off)
tf
toff
(0.25µs)
0.45µs
0.70µs
(0.75µs)
0.35µs
1.1µs
MAXIMUN RATINGS AND ELECTRICAL CHARACTERISTICS OF FWD Tc=25℃
Forward Current
DC
IF
100
A
1ms
IFM
200
A
Maximum DC or pulse forward current of
built-in diode
8
Ratings and Characteristics
Characteristics
Symbol
Test Condition
Min.
Typ.
Max.
Unit
Forward Voltage
VF
IF=100A, VGE=0V
1.9
2.4
V
Reverse Recovery Time
trr
IF=100A, VGE=－10V
－di/dt = 200A/µs
0.2
0.3
µs
Forward voltage of built-in diode at specified current
Required time for built-in diode to recover reverse blocking state
Reverse Current
Definition of reverse recovery time
THERMAL CHARACTERISTICS
Characteristics
Thermal Resistance
Symbol
IGBT
Min.
Condition
Typ.
Rth(j-c) Junction to Case
Diode
Max.
Unit
0.24
℃/W
0.42
Thermal resistance of each of IGBT or built-in diode
Measuring point of Case
temperature
IGBT
Diode
Junction temperature
0.24℃/W
0.24℃/W
0.42℃/W
Case temperature
* Measuring point is at the
center of metal base plate.
* Thermo-couple is inserted
into a hole of 1mm in diameter and 5mm in depth.
To define Rth(j-c), Tc is
measured at metal base plate
just below IGBT or diode chip.
Contact thermal
resistance
Heatsink temperature
Heatsink thermal
resistance
Ambient temperature
9
0.42℃/W
Power Loss and Thermal design
Power loss in IGBT consists of steady-state (conduction) loss and switching loss. And,
switching loss is sum of turn-on loss (Eon) and turn-off loss (Eoff) Also, that’s of builtin diode is sum of steady state and switching (ERR - reverse recovery). You can calculate average loss by multiplying EON, EOFF, ERR times switching frequency.
IGBT Losses
Collector current
IC
Collector-Emitter Voltage
VCE(sat)
Steady State
Turn-on EON
Collector Loss
IC×VCE(sat)
Reverse Recovery Loss
Current
Voltage
Reverse Recovery Loss ERR
10
Turn-off EOFF
Power Loss and Thermal Design
Measuring switching characteristics
RG
－15V
iC
VCC
iC
RG
+15V
－15V
time
900
30
2
250
750
20
1
200
600
10
0
150
VGE (V)
300
VCE (V)
3
IC (A)
IG (A)
PDMB100B12 Typical Tun-on and EON
450
Turn-On / 100A/1.2kV/SPT
at VCC=600V, IC=100A, RG=10Ω, VGE=±15V, TC=125℃
VGE
0
-IG
IC
-1
100
300
-10
-2
50
150
-20
-3
0
0
-30
VCE
5.4x10
-5
-5
5.6x10
t : 2 . 0μ s/ DIV
5.8x10
-5
6x10
-5
6.2x10
-5
0.02
1.0x10
5
0.015
7.5x10
4
5.0x10
4
2.5x10
4
0.0x10
0
P (W)
ESW (J)
Time (s)
0.01
0.005
0
P
EON
t : 2 . 0μ s/ DIV
5.4x10
-5
5.6x10
-5
5.8x10
2
250
750
20
1
200
600
10
0
150
450
VGE (V)
30
VCE (V)
900
IC (A)
100
300
-10
-2
50
150
-20
-3
0
0
-30
-2x10
-5
6.2x10
Turn-Off / 100A /1.2kV /SPT
at VCC=600V, IC=100A, RG=10Ω, VGE=±15V, TC=125℃
VCE
-IG
0
-1
VGE
IC
-6
-1x10
-6
0x10
-6
t : 1 . 0μ s/ DIV
-6
1x10
2x10
-6
3x10
-6
4x10
-6
5x10
-6
Time (s)
0.02
1.0x10
5
0.015
7.5x10
4
5.0x10
4
2.5x10
4
0.01
0.005
0
P (W)
ESW (J)
IG (A)
300
6x10
Time (s)
PDMB100B12 Typical Tun-off and EOFF
3
-5
P
EOFF
t : 1 . 0μ s/ DIV
0.0
-2x10
-6
-1x10
-6
0x10
-6
1x10
-6
2x10
Time (s)
11
-6
3x10
-6
4x10
-6
5x10
-6
-5
Power Loss and Thermal Design
1200V B-series Turn-on Loss EON （Tj= 125℃）
Find RG (gate series resistance) on Datasheet.
VCC=600V
Tj=125℃
VGE=±15V
Half Bridge
1200V B-series Turn-off Loss EOFF （Tj= 125℃）
Find RG (gate series resistance) on Datasheet.
VCC=600V
Tj=125℃
VGE=±15V
Half Bridge
12
Power Loss and Thermal Design
1200V B-series Dependence of RG on EON （Tj= 125℃）
VCC=600V
IC=Rated IC
Tj=125℃
VGE=±15V
Half Bridge
1200V B-series Dependence of RG on EOFF （Tj= 125℃）
VCC=600V
IC=Rated IC
Tj=125℃
VGE=±15V
Half Bridge
13
Power Loss and Thermal Design
1200V B-series Diode Reverse Recovery Loss ERR （Tj= 125℃）
Find RG (gate series resistance) on Datasheet.
VCC=600V
Tj=125℃
VGE=±15V
Half Bridge
1200V B-series Dependence of RG on ERR （Tj= 125℃）
VCC=600V
IC=Rated IC
Tj=125℃
VGE=±15V
Half Bridge
14
Power Loss and Thermal Design
Losses in IGBT Module
IGBT
FWD
IGBT
Steady-State Loss
Switching Losses（Turn-on Loss EON, Turn-off Loss (EOFF）
FWD
Steady-State Loss
Switching (Reverse Recovery) Loss ERR
Calculation of Average Loss in a Chopper circuit
IGBT
IGBT
Vcc
RG
3:
FWD
FWD
1:
An example of average loss calculation
PRHMB100B12、Vcc=600V、Ic=100A、RG=10Ω、VGE=±15V、f=10kHz、Duty:3:1
IGBT Steady-state Loss : 100(A)×2.2*1(V)×3/4＝160(W)
Turn-on Loss : 9.5(mJ)×10(kHz)＝95(W)
Turn-off Loss : 9.5(mJ)×10(kHz)＝95(W)
IGBT Loss in total : 350(W)
FWD Steady-state Loss : 100(A)×1.9*2(V)×1/4＝47.5(W)
Switching (Reverse Recovery) Loss : 8.5(mJ)×10(kHz)＝85(W)
FWD Loss in total : 132.5(W)
Module Loss 482.5(W)
*1 Collector-Emitter saturation voltage @ Ic=100A, TJ=125℃
*2 Forward voltage @ IF=100A, TJ=125℃
15
Dissipation and Thermal Design
Calculations follow the condition on previous page.
Junction to Case Temperature Rise
FWD
IGBT
Rth(j-c)=0.42℃/W
Temperature Difference
between Tc and Tj
Rth(j-c)=0.24℃/W
IGBT
FWD
84℃
(350×0.24)
55.65℃
(132.5×0.42)
Case temperature Tc
Case to Fin, and Case to Ambient Temperature Rise
Contact thermal resistance Rth(c-f)
Fin thermal resistance Rth(f-a)
Case temperature Tc
5mm
Fin temperature Tf
Ambient temperature Ta
Temperature difference between Tc and Tf,
and between Tf and Ta
16
Tc－Tf
Rth(c-f)×482.5
Tf－Ta
Rth(f-a)×482.5
Dissipation and Thermal Design
Loss and Temperature Rise in 3-phase Inverter
We cannot easily estimate losses for applications which have sophisticated operating waveform, such as PWM inverter. In these cases, we recommend directly measure losses, using
DSO. (Digital Storage Oscilloscope) which features computerized operation. (For example,
Tektronix introduces TDSPWR3 software to analyze complicated losses.)
For choice of heatsink, an example how to evaluate losses is shown below.
EXAMPLE
PTMB75B12C, Inverter output current (IOP) 75A, Control Factor (m) 1, Switching frequency (f) 15kHz, Power factor cosφ 0.85
IGBT
FWD
IGBT
FWD
IGBT
FWD
IGBT
FWD
IGBT
FWD
IGBT
FWD
Let’s review losses in IGBT module. Losses in IGBT are sum of steady-state
(conduction) loss Psat, turn-on loss PON, and turn-off loss POFF. And, losses in
FWD are sum of steady-state loss PF and reverse recovery loss PRR.
Psat＝
1
π
∫ ｛IOP sinθ×VCE(sat) sinθ×(1－m sin(θ + φ)/2｝ dθ
2π
0
1
＝IOP VCE(sat)
（
8
＋
m
3π
cosφ
）
Given IOP＝75A, VCE(sat) ＝2.2V (125℃), m＝1, cosφ＝0.85,
Psat＝35.5(W)
1
2π
∫ ｛(-IOP sinθ)×(VF sinθ)×(1－m sin(θ + φ)/2｝ dθ
2π
PF=
0
= IOP VF
1
（
8
－
m
3π
cosφ
）
VF of FWD is 1.8V @75A、125℃;
PF=4.7W
Referring datasheet, we know turn-on loss, turn-off loss, and reverse recovery loss
per pulse are 7.5mJ、7mJ、and 6mJ, respectively. Multiplying frequency (15kHz)
and 1/π, we after all have average losses.
EON＝35.8(W)、EOFF＝33.4(W)、ERR＝28.6(W)
*1
1
π
∫ sinθ dθ
2π
0
17
Dissipation and Thermal Design
Loss and Temperature Rise in 3-phase Inverter (Continued)
Loss per IGBT and FWD
Average Loss
per IGBT
Average Loss
per FWD
104.7W
33.3W
(Psat+PON+POFF)
(PF+PRR)
Loss in each element
Total Loss
828W
Temperature Rise of each element
IGBT
Rth(j-c)=0.3℃/W
∆T(j-c)＝31.4℃
FWD
Rth(j-c)=0.6℃/W
∆T(j-c)＝20.0℃
18
Dissipation and Thermal Design
Junction to Case Transient Temperature Rise
On previous page, the temperature rise is average (steady-state) value. Using transient
thermal resistance, you can calculate peak temperature, when necessary.
P
t1
t2
t3
∆T(j-c) = P×(t1/t3)×{Rth(j-c)－rth(t3+t1)}＋P×(rth(t3+t1)－rth(t3)＋rth(t1)}
rth(t) is transient thermal resistance at time t
Check which is the highest temperature among IGBT elements, and consider transient temperature variation over average temperature.
19
Gate Drive
Rated (Maximum) Gate Drive Voltage
Gate
n+
Emitter
p
n+
Gate voltage range should be within ±20V
SiO2
Exceeding this rating may destroy gate-emitter
oxide （SiO2）, or degrade reliability of IGBT.
n
Zener Diode (18V
or so) to absorb
surge voltage
n+
p+
Collector
On-Gate Drive Voltage
IC=100A (VCE=600V)
VGE
8V
10V
12V
15V
VCE(on)
(600V)
2.25V
2.05V
1.95V
PC
(60,000W)
225W
205W
195W
Lower gate voltages, such as 12V or 10V, cause an
increase in collector loss. Lower voltage as low as
6V cannot lead IGBT to be on-state, and collectoremitter voltage maintains near supply voltage. Once
such a low voltage is applied to gate, IGBT may possibly be destroyed due to excessive loss.
Standard On Gate Drive Voltage is +15V.
Reverse Gate Bias Voltage during Off-period （- VGE）
＋VGE
To avoid miss-firing, apply reverse gate
bias of (-5V) to -15V during off-period.
RG
－VGE
(-5V) ～ -15V
Standard : -15V
20
Gate Drive
Dependence of on-gate voltage and off-gate bias
on switching speed and noise
Increase in on-gate voltage (+VGE) results in faster
turn-on, and turn-on loss becomes lower. It follows additional switching noise.
As a matter of course, higher off-gate voltage (VGE) causes higher turn-off speed and lower turnoff loss. As expected, it follows higher turn-off
surge voltage and switching noise.
RG, +VGE, and -VGE are major factors which significantly affect switching speed of IGBT.
＋VGE
RG
－VGE
Effect of gate resistance RG on switching
RG
Gate Capacitance
Gate
Collector
Emitter
CGC
CCE
Gate
CGE
CGE
CGC
Emitter
CCE
Input Capacitance
Cies = Cge + Cgc
Reverse Transfer Capacitance Cres = Cgc
Output Capacitance
Coes = Cce + Cgc
Collector
21
Gate Drive
Gate Reverse Bias Voltage and Gate-Emitter Resistance RGE
RG
－15V
+15V
Displacement
current
RG
High dv/dt
－15V
Displacement current flows
due to high dv/dt, and gate
voltage rises.
Bypass resistance RGE
10kΩ or larger
Inrush current due to
reverse recovery of
FWD and high dv/dt
IC
Reverse gate bias and bypass resistance
surpress inrush current and accompanied loss.
Gate Wiring
To be free from harmful oscillation, be sure to confirm following points.
Twist
Minimize loop area
*Set gate wiring as far as possible from power wiring, and do not set parallel to it.
*If crossing is inevitable, cross in right angles.
*Do not bundle gate wiring pairs.
*Additional common mode inductor or ferrite bead to gate wiring is sometimes effective.
22
Gate Drive
Using Gate Charge to estimete Drive Current and Power
RL
＋VGE
15V
CGC
CGE+CGC
RG
VCE
CGC
iG
－VGE
CGE
Gate Drive Dissipation PG, Peak Gate
Drive Current iGP
（+VGE=15V、-VGE=-15V、f=10kHz）
CGE
690nC
PG=｛（+VGE）-（-VGE)｝×Qg×f
＝30×690×10-9×104
＝0.207 (W)
Assuming turn-on time is 500ns ;
iGP = Qg / ton
＝690×10-9 / 500×10-9
＝1.4 (A)
23
High Side Drive
High Side and Low Side
V+
IGBT is driven referred to emitter voltage.
During switching operation, emitter voltage
of high side IGBT VE swings from 0V to
bus voltage V+. So, required gate drive voltage for high side IGBT in AC200V circuit is
as high as 300V (bus voltage) plus 15V,
315V. Consequently, we need high side
drive circuit not influenced by switching
operation.
High Side
VE
Low Side
LOAD
High Side
Emitter Voltage VE
V+
High Side
Gate Voltage
V+ plus 15V
Optocoupler or high voltage driver IC is usable solution these days.
High Side Drive Using Optocoupler
+VGE
For high power applications,
optocoupler is utilized for isolation, and, discrete buffer is
added as output stage.
For medium or less power applications, hybrid IC integrated in a
package illustrated on the left is
a popular choice.
IN
-VGE
* Use high common mode rejection (CMR) type.
* To minimize dead time so as to decrease IGBT loss, use one with shortest transfer delay
times, tPLH and tPHL. tPLH and tPHL are differences in delay time for output changes from L to H,
or L to H, referred to input, respectively.
* Major suppliers are Toshiba, Agilent Technologies, Sharp, NEC, and etc.
* Application note of Agilent Technologies indicates that optocoupler ICs are recommended to
200VAC motor driver of 30kW or less (600V IGBT), and to 400VAC driver of 15kW or less
(1,200V IGBT). （For higher power applications, discrete optocoupler plus buffer is used as
gate driver.)
24
High Side Drive
High Side Drive using Driver IC
Bootstrap
diode
Bootstrap
capacitor
Available line-ups are;
High side
Half bridge
High and Low
3-phase bridge
Many have rating of 600V, while
some have of 1200V.
Vcc
IN
COM
* Bootstrap diode should be fast recovery type, and its VRRM should be
same as VCES of IGBT.
* For bootstrap capacitor, use high frequency capacitor, such as film or
ceramic, or add it in parallel.
* Reduce line impedance of Vcc as small as possible.
Optocoupler vs. Driver IC
Comparison between the two are as follows.
Optocoupler
Driver IC
Application Technique
Relatively easy
Relatively not easy
Structure
Hybrid
Monolithic
Tough on use
AC400V line
Typical Vcc current
10mA
Less than 2mA
Dead time
More than 2µs
Less than 1µs is available
Assembly area
Large
Small
Protection
Built-in some
Plus current sensing
Especially useful for 3phase 2.2～3.7kW
Inverter output
Improvements
Drive capability, Protection, Noise margin, Less difference in
characteristics, Integrated current-sensing, etc
25
3-Phase Inverter
3-phase Induction Motor Driver and Output Timing Chart
Inrush current Protection
TrV
TrU
R
S
T
TrW
U
V M
TrX
TrY
W
TrZ
Over current sensing
DC-DC
Converter
U
V
W
X,Y,Z
Protection
Gate Driver
CPU & Logic
TrU
TrV
TrW
TrX
TrY
TrZ
0
120
240
0
120
240
26
0
120
240
0
120
240
0
3-Phase Inverter
AC line Voltage and Corresponding IGBT Rated VCES
AC Line Voltage
200
～240V
200～
400
～480V
400～
575, 690V
IGBT VCES
600V
1200V
1700V
Motor Output and IGBT Rated IC (3-phase bridge）
IAC=P / (√3×VAC×cosθ×η)
IAC : Motor Drive Current (ARMS)
P ： 3-phase Motor Output (W)
VAC ： Rated Voltage (VRMS)
cosθ ：Power Factor
η : Efficiency
Assuming power factor is 0.8, and efficiency is 70%,
IAC=P / (0.970VAC)
IC = √2×IAC×1.1×1.1×Kg×1.3
Temperature Derating
Derating for short period overload :
1.2
Derating for distortion in output
current
Derating for line voltage fluctuation
AC200V applications
AC400V applications
IC = 0.0138P
IC = 0.00688P
3-phase Motor
Output
AC200V
IC of 600V IGBT
AC400V
IC of 1,200V IGBT
3.7kW
50A (51.0A)
25A (25.5A)
5.5kW
75A (75.9A)
7.5kW
100A (103.5A)
50A (51.0A)
15kW
200A (207A)
100A (103.5A)
30kW
400A (414A)
200A (207A)
45kW
600A (621A)
300A (309.6A)
55kW
400A (379.5A)
（ ）: Calculated Value
27
3-Phase Inverter
An example of AC200V 3-phase 2.2kW Inverter Circuit
Shown below is an example for study, and not for practical use. It is referred to March, 1999
issue of Transistor Gijutsu under approval of the author, Mr. Hajime Choshidani.
Original is designed for 0.75kW output, and is partially modified for 2.2kW output.
+5V
91Ω
0.022µF
74HC14
4
CPUへ
100p
3
910Ω
91Ω
PGH508
TLP620
1
2
PTMB50E6(C)
0.1µF
0.1Ω 10W
3パラ
20Ω
TrU
20Ω
TrV
1ZB18
15kΩ
15kΩ
C*
C*
560µF×2 (3)
400WV
20Ω
TrW
1ZB18
1ZB18
R
S
T
20Ω
TrX
20Ω
TrY
1ZB18
15kΩ
C*
20Ω
TrZ
1ZB18
1ZB18
15kΩ
15kΩ
15kΩ
U
V
W
C* : 0.1～0.22µF 630V
+15V
Insulated
DC-DC
Converter
+15V
+15V
+15V
U
360
CPU
V
W
X
Y
Z
360
74HC04
360
360
74HC06
28
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
8
7
6
5
8
7
6
5
8
7
6
5
8
7
6
5
TLP250
360
TLP250
0.1µ
TLP250
100µ
TLP250
47kΩ×6
8
7
6
5
TLP250
10µ 0.1µ
1
2
3
4
TLP250
360
+5V
8
7
6
5
0.1µ
Gate
Emitter
TrU
Gate
Emitter
TrV
Gate
Emitter
TrW
Gate
Emitter
TrX
ゲート
エミッタ
TrY
Gate
Emitter
TrZ
0.1µ
0.1µ
0.1µ
0.1µ
0.1µ
3-Phase Inverter
Designing 3-phase Inverter using Driver IC
Design note how to apply 600V 3-phase driver IC IR2137 and current sensing IC IR2171 to
2.2kW inverter is available from International Rectifier (IR).
http://www.irf-japan.com/technical-info/designtp/jpmotorinv.pdf
Also, you can buy the design kit IRMDAC4 from IR.
http://www.irf.com/technical-info/designtp/irmdac4.pdf
These are very helpful to know driver IC.
Capacitor
Noise Filter
IR2137
IGBT Module
IR2171
Design kit
using driver IC IR2137 and current sensing IC IR2171
（International Rectifier）
29
Short-circuit and Over-voltage Protection
Flow to protect short-circuit and over-voltage
Abnormal happens.
Why happened?
Over-current flows.
Monitor the current
（Where? By what?）
Or monitor C-E voltage.
Over the design criteria?
Shut down IGBT within 10µs
(Unless the IGBT will be failed.）
C-E voltage and turn-off loss increases due to over–current
Soft turn–off and proper snubber
are required.
Short Circuit 1.2kV/ 100A /SPT VCC=900V, t=10μs, TC=125℃, RG=24Ω, Lσ=50nH
30
4x10 6
1250
1250
20
3.2x10
6
1000
1000
10
2.4x10
6
1.6x10
6
500
500
-10
8x10 5
250
250
-20
0x10 0
0
0
-30
P (W)
750
750
VGE (V)
1500
VCE (V)
1500
IC (A)
6
4.8x10
VCE
0
IC
VGE
-5x10 -6
PC
0x10 -6
5x10 -6
10x10 -6
15x10 -6
20x10 -6
Time (s)
10µs short circuit SOA operation without additional protectiive devices.
30
Short-circuit and Over-voltage Protection
Causes and Sensing of short-citcuit current
Causes
Current Sensors
INVERTER
Device or Controller failure, Case isolation
LOAD
Load failure, Arm short-circuit, Ground fault
Current Transformer CT
（AC, DC, or HF type）
Shunt Resistor
Current Sensing IC
Arm short-circuit due to device failure or to controller failure (Insufficient dead-time)
①
TrU
R
S
T
TrV
TrW
U
④
TrX
V M
TrY
TrZ
W
③
②
Short-circuit current due to series arm
①
TrU
R
S
T
TrV
TrW
U
④
TrX
V M
TrY
TrZ
W
③
②
Short-circuit current due to ground fault （Through ① or ② path）
①
TrU
R
S
T
TrV
TrW
U
④
TrX
②
31
TrY
V M
TrZ
W
③
Short-circuit and Over-voltage Protection
Collector-Emitter Surge Voltage during turn-off of short-circuit current
RG
Stray inductance Ls
10～
15kΩ
18V ZD
In the event of arm (load) short-circuit, current is so large because it is only limited by ESR of
electrolyte capacitor and gain of IGBT. Corresponding loss is also large, and IGBT will fail
unless it is not turned-off within 10µs. Simultaneously, it followed by surge voltage
(inductive voltage kick), and which is the product of collector-emitter stray inductance Ls and
-di/dt. Assuming Ls is so small as 0.1µH, the voltage reaches as high as 200V if -di/dt is
2,000A/µs. To reduce -di/dt, IGBT should be turned-off slowly. In addition to soft turn-off,
stray inductance should be minimized as small as possible
During transition from on-state to off-state, collector voltage rises. As a result, gate is charged
up through reverse transfer capacitance Cgc. Given this situation, collector current is increased more and more, and gate is possibly destroyed. We recommend addition of both bypass resistor and zener diode between gate and emitter terminals.
Collector Current IC
-dic/dt
IC
∆V＝Ls×-dic/dt
IGBT may be destroyed by
the voltage spike which exceeds C-E voltage rating.
Collector-Emitter Voltage VCE
32
Short-circuit and Over-voltage Protection
Snubber
At turn-off, stored energy in inductance generates surge voltage, which is applied to collector-emitter of IGBT. As snubber capacitor is responsible for a part of turn-off energy, snubber circuit can suppress over-voltage and incidental turn-off loss. As a matter of course,
stacked up energy in capacitor should be dissipated properly.
RCD Snubber
Stored energy at turn-off :
1/2・LiC2
L
E
e+＝ L・diC/dt
iC
e
IGBT
－ L +
diC/dt
iC
E
iS
∆e
iC
E
IGBT
Cs e
iC
E
iS
－ L +
E
IGBT
iton
Discharge current limiting
resistor
Discharge current of Cs
iC
iC
Cs
Charge during turn-off.
Discharge during turn-on.
33
Assuming all the energy
in L is transferred to Cs,
1/2・L・iC2＝1/2・Cs・∆e2
So,
∆e＝ i0×√L/Cs
Short-circuit and Over-voltage Protection
Loss in RCD Snubber
L
vs
∆e
iC
Rs
vCE
Ds
diC/dt
Cs
Snubbers individually connected to each IGBT are more effective than ones between DC bus
and ground. But, we have a difficulty that loss in Rs is large. Loss in Rs is Lic2 times switching frequency, for example, the loss is 20W, assumed L=0.2µH, ic=100A, and f=10kHz. In this
case, total snubber loss reaches as high as 120W in 3-phase circuit. So, our choice is to set frequency lower, or, to regenerate the energy.
To reduce ∆e, minimize stray inductance in main circuit loop at first, so we will have a smaller
Cs in accordance to the reduced inductance.
The vs is the sum of (dic/dt)×(stray inductance of wiring), forward recovery voltage of Ds,
and dic/dt × (stray inductance of Cs).
Considerations on snubber are;
*Drive IGBT in lower -dic/dt. (Turn-off IGBT slowly.)
*Place electrolytic capacitors as close to IGBT module as possible, apply copper bars to wiring,
and laminate them where possible, so as to minimize wiring inductance of main circuit
*Also, set snubber as close to IGBT module as possible, use high frequency oriented capacitors, such as film capacitors.
*Use low forward recovery, fast and soft reverse recovery diode as Ds.
Popular Snubbers
Shown are lump snubbers (between power buss and ground).
Snubber1
Snubber2
Snubber3
34
Short-circuit and Over-voltage Protection
Guideline of Snubber Capacitance
Snubber1 on previous page cuts damping resistor, and sometimes oscillations occur on
power buss. So, it is fit for lower power applications. Among 3 types of snubbers, you
will find which is the generic choice, and capacitance for lump snubber below. Half of
the capacitance is right value when snubber is attached to each IGBT.
IGBT IC
10A
50A
100A
200A
300A
400A
0.47µF
3.3～4.7µF
1.5～2µF
Snubber
Snubber1 or 2
Snubber3 and 1
Snubber3 or 2
In highest power applications, snubbers would be not enough to be free
from device failure or malfunction due to noise otherwise wiring inductance could be minimized using copper bars or laminated them.
Discharge Surpressing Snubber (Snubber3)
L
Cs
Rs
Cs
Rs
Assuming all of the stored energy in L is absorbed by Cs,
1/2・L・iC2＝1/2・Cs・∆e2
Thus,
Cs＝L×(iC/∆e)2
Charge in Cs must be fully discharged before the next turn-on, and we focus on time constant (Cs×Rs). To discharge below 90%;
Rs≦1/(2.3・Cs ・f) f : switching frequency
This relationship indicates minimum value of Rs. In addition, an excessively small Rs may result in harmful oscillation at turn-on, so, somewhat
larger resistance would be preferable.
Dissipation in Rs, P(Rs), is independent of Rs.
P(Rs)＝1/2・L・iC2
35
Parallel Operation
Parallel Operation and Current Imbalance
We introduce high current IGBT modules, which extend to 1,200A for 600V series, and
800A for 1,200V series. So, we cover up to 100kW 3-phase inverters. Consequently, parallel operation of IGBT modules is not so important, but, when designing 3-phase inverters, information on rules for parallel operation may possibly be useful.
Let us show you the points in brief.
Ic1
Ic2
Lc2
Lc1
Gate Driver
RG
IGBT-1
RG
IGBT-2
L E2
L E1
Current sharing during parallel operation depends on both circuit design and device
characteristics.
Oscillations caused by gate-emitter wiring inductance LG、resistance RG、and Cies, will
possibly be the origin of device failures as a result of malfunction or non-saturation of
IGBT. Minimal RG required is in proportion to √LG. Accordingly, minimize the inductance, and RG should also be larger than or equal to recommended.
Ic2
Ic1
(Lc1＋LE1)＞
(Lc2＋LE2)
Turn-on
VCE(sat)1＞VCE(sat)2
Steady-state
Turn-off
*Differences in wiring inductance lead to poor current sharing at turn-on or at turnoff. Collector and emitter wiring to each IGBT should be equal and minimal.
*Each IGBT needs gate resistor, and gate wirings should also be equal and minimal.
Connect emitter wiring to auxiliary emitter terminal, not to main emitter terminal.
*Saturation voltage VCE(sat) and some other characteristics are depend on temperature.
Obtain smallest possible deference in temperature rises among modules.
36
Parallel Operation
VCE(sat) Rank for Parallel Operation
Some current imbalance in parallel operation is inescapable, and handling current per
module is roughly decreased to 80%. For example, expected total current of 4 300A
modules in parallel is 300×0.8×4=960A.
On your request, we can ship VCE(sat) ranked modules for larger than 1,200A/600V or
800A/1200V applications. Contact us for further information.
For your repeat order when repair is needed, we ship group of modules in a VCE(sat)
rank, but the rank may not be same as the original.
37