Specifications

38
Dec. 2012
Mitsubishi IPM-series Application Note
(3) Average Power Loss
The average power loss per pulse is
1w
1
1
t
E
P =
(W)
Fig.10.4 is approximation of Fig.10.1 by using rectangle wave.
Fig.10.4
Average power loss during period of tw2 is (See Fig.10.5)
N
t
E
P
2w
1
av
×= (W)
N㧦pulse numbers in tw2 period
Fig.10.5
Total average power loss is (See Fig.10.6)
2
2w
avAV
T
t
PP ×=
(W)
Fig.10.6
b. Junction Temperature Calculation
Junction temperature can be calculated by using P1, Pav, and PAV that has been obtained so far. Three cases should be
considered according to pulse width.
(1) tw1 is short (tw1<<1ms)
(2) Both of tw1 and tw2 are long(1ms<tw1<tw2<1s)
(3) tw2 is longer than 1s.(tw2>1s)
Power Loss and Junction Temperature