pm75cs1d120 Mitsumi Electronics, Corp., pm75cs1d120 Datasheet - Page 44

• Manufacturer Part Number: pm75cs1d120
• Description: Mitsubishi Ipm L1/s1-series Application Note Igbt Modules
• Manufacturer: Mitsumi Electronics, Corp.

(3) tw2>1s
c. Heat-sink Selection
necessary to know the transient heat impedance of the heat-sink. (Fig.12.9)
formula.
when two or more modules are mounted on one
heat sink.
of the heat sink is
formula.
Fig.12.10 shows the thermal equivalent circuit
According to this equivalent circuit, the temperature
In a similar way to (2), temperature change of heat-sink should be taken into consideration as well. It is
Similarly, the temperature difference between junction and ambient can be calculated by using the following
Tf Ta (P
The case temperature Tc is,
Tc Tf (P
Tc(max) can be calculated by using the below
Therefore, the heat-sink to ambient thermal
T(j-a) R
Tj Ta
T
resistance can be computed as
Ta Ambient temperature
P
P
N: Arm number
R
resistance
Rth(c-f) The case to heat-sink thermal
resistance
R
c(max)
T(AV)
D(AV)
th(f-a)
th
P
f (
D(AV)
:Average power loss of IGBT
:Average power loss of FWDi
:The heat-sink to ambient thermal
) a
) R
R
Ta (P
T(AV)
T(AV)
th(j-a)
th(j-a)
T
T(j-a)
C
th(c-f)
(max)
P
P
T(AV)
P
P
D(AV)
D(AV)
AV
AV
T
) R
) NxR
P (
Z
(P
P
a
th(j-a)(tw2)
D(AV)
( T
av
P (
AV
th(c-f)
) NxR
( T
)
P
th(f-a)
AV
AV
(Ta is measured by a thermometer.)
Power Loss and Junction Temperature
P
) Z
)
D
P
(
AV
AV
P
th(f-a)
D
th(j-c)(tw2)
)
)
(
AV
Z
N
th(j-a)(tw2)
)
)
(P
R
T(AV)
th
(P1 Pav) Z
c (
Fig.12.9
44
Pav Z
) f
th(j-a)(tw1)
th(j-c)(tw1)
Moreover, power loss of FWDi should be
considered as well. In thermal design, the
allowable case temperature Tc(max) is up to the
smaller one of IGBT power loss and FWDi part.
Fig.12.10 Thermal Calculation Model
Pav Z
th(j-a)(tw1)
P1
Sep. 2008