Transcript Slajd 1 - Akademia Morska w Gdyni

PA
DE
Nonlinear Compact
Thermal Model of SiC
Power Semiconductor
Devices
O
FM
RTMEN
ARINE
Krzysztof Górecki, Janusz Zarębski,
Damian Bisewski and Jacek Dąbrowski
Department of Marine Electronics
Gdynia Maritime University, POLAND
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N IC
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Outline
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Introduction
The form of the nonlinear thermal model
Estimation of the model parameters
Verification of the model accuracy
Conclusions
2
Introduction (1)
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The thermal models are indispensable for calculating the
device internal temperature.
There are the microscopic and the compact thermal
models used for this purpose.
In the thermal analysis of electronic networks the
compact thermal models are typically used.
The network representation of the compact thermal
model is frequently used.
This representation consists of the current source
representing the dissipated power and the Cauer or the
Foster network representing the transient thermal
impedance Z(t)
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Introduction (2)
a)
R1
R2
b)
Foster Rn
Tj
C1



Cauer R'1
R'2
R'n Ta
Ta
pth
pth
Tj
C2
Cn
Ta
C'1
C'2
C'n
Ta
Both the networks are fully equivalent from the point of view
the terminal Tj, representing the device internal temperature.
The efficiency of abstraction of the heat dissipated in
semiconductor devices depends on many factors, e.g. on the
dissipated power.
The thermal models presented in literature are the linear
models, which do not take into account the dependence of
the Z(t) on the dissipated power.
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In the paper
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In the paper the compact nonlinear thermal
model of SiC devices is proposed.
This model was experimentally verified for SiCMESFET and SiC-SBR
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The form of the nonlinear thermal
model

Formulating of the nonlinear thermal model
1. The device transient thermal impedance in the wide
range of the dissipated power should be measured.
2. The values of the elements Ri,Ci (Cauer network) are
estimated at various values of the power.
3. The dependence Ri(pth) and Ci(pth) are drafted.
Then, on the basis of these dependences, the
proper approximation function is fitted.
4. The values of the parameters existing in the
dependences Ri(pth) and Ci(pth) are estimated.
5. The proper model of the network form is formulated
and implemented to SPICE.
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The form of the nonlinear
thermal model
eRN
eR2
eR1
Tj
...
.
pth
iCi  Ci 
iC1
dui
dt
iC2
iCN
eRi  Ri  iRi

 p  pi1 
 p  pi 2 
  a i 2  exp  th

Ci  Ci 0  1  a i1 .  exp  th
b
b
i1
i2






 p  pi 3 
 p  pi 4 
  d i 2  exp  th

Ri  Ri 0  1  d i1 .  exp  th
e
e
i1
i2





Ci0, ai1, ai2, bi1, bi2, di1, di2, ei1, ei2, Ri0, pi1, pi2, pi3, pi4 are the model parameters.
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Estimation of the model parameters
The estimation was performed for the diode SDP10S10 and
MESFET CRF24010F

100
100
CRF24010F
R4
1
Ci [J/K]
Ri [K/W]
CRF24010F
10
R6
10
C6
C4
0,1
0,01
1
0,001
R1
C1
0,0001
0,00001
0,1
0
0,5
1
1,5
2
2,5
3
0
3,5
0,5
1
1,5
Ci0
10-5
0.003
0.13
0.27
0.4
9.2
ai1
10
0.9
0.9
0.9
0.9
0.9
ai2
-5
-0.7
-0.7
-0.7
-0.7
-0.7
2,5
3
3,5
p [W]
p [W]
i
1
2
3
4
5
6
2
bi1
-3
1.5
2.5
2.5
2.5
2.5
bi2
10
3
5
6
6
6
Ri0
0.2
23
1.65
2.5
700
163
di1
0.3
-0.3
0.3
3
-0.15
-0.15
di2
0.7
-0.7
0.7
3
-0.85
-0.85
ei1
0.5
35
1
0.7
35
35
ei2
4
78
24
3
90
90
pi1
0.5
2
2
2
2
2
pi2
2
3
3
3
3
3
pi3
2
-2
2
1
-2
-2
pi4
1
-3
1
1
-4
-4
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Verification of the model accuracy
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p = 3.3 W
p = 4.7 W
Z(t) [K/W]
25
20
p = 5.7 W
15
p = 0.21 W
CRF24010F
p=1W
p = 2.1 W
80
Z(t) [K/W]
30
100
SDP10S30
p = 0.51 W
p = 1.06 W
p = 1.5 W
o
Ta = 20 C
60
p = 2.03 W
p = 2.72 W
40
10
20
5
0
0,0001
0,001
0,01
0,1
1
t [s]
10
100
1000
10000
0
0,0001
0,001
0,01
0,1
1
10
100
1000
10000
t [s]
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Verification of the model accuracy
80
100
SDP10S30
70
device without any heat-sink
80
60
70
Rth [K/W]
Rth [K/W]
CRF24010F
90
device without any heat-sink
50
40
device on the heat-sink
30
60
50
40
30
20
device on the heat-sink
20
10
10
0
0
0
1
2
3
p [W]
4
5
6
0
2
4
6
8
10
p [W]
10
Conclusions
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In the paper the compact nonlinear thermal model of SiC
semiconductor devices is proposed.
The accuracy of this model is verified on the example of the power
MESFET transistor CRF24010F and the Schottky diode SDP10S30.
A good agreement between the measurements and the calculations
with the use of the new model in the wide range of changes of the
device dissipated power and for various conditions of theirs cooling is
achieved.
The examples show a strong influence of the power dissipated in the
device on the values of its thermal parameters – the thermal
resistance and the transient thermal impedance.
For the device operating without a heat-sink, the changes of thermal
resistance corresponding to the considered changes of the power
equal to even 25% are observed.
The proposed nonlinear thermal model can be used in the construction
of the electrothermal models of the considered power semiconductor
devices, dedicated to the analyze and design electronic circuits.
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