Hitachi IGBT Module Application Manual
5
5.1
Operating Parameters
Derating Factors
To ensure IGBT module reliability, follow each of the derating factors listed below.
5.1.1 Voltage
Maximum peak voltage should not exceed 80% of the rated voltage V
CES
, and the DC voltage should
not exceed 50 to 60% of V
CES
.
Note:
Equation 1:
Use Equation 1 to calculate the rated voltage of an IGBT module
for a given AC line input voltage at the inverter.
2
+ V
s
+ V
reg
+
α
Rated voltage of IGBT module
Input voltage of AC line
Overshoot voltage
Increased voltage dependence on regeneration
Margin
V
CES
= V
in
Definitions:
V
CES
V
in
V
s
V
reg
α
5.1.2 Current
Maximum repetitive current peak value I
p
should not exceed 70 to 80% of the rated DC current I
C
.
Because faults, such as load short circuit, are taken into account for the one millisecond rated current
I
cp
, this value cannot be used repeatedly.
Note:
Equation 2:
Use Equation 2 to calculate the rated current of an IGBT module
based on the peak current of the inverter.
3
!
2
!
λ
I
p
= P
inv
!
κ ÷
V
ac
/
Definitions:
I
p
P
inv
( VA )
Peak current of inverter
Inverter capacitance
(equals motor capacitance divided by efficiency)
Overload factor
κ
V
ac
( V
rms
) AC voltage
Ripple factor
λ
5.1.3 Temperature
To use the overload of the motor, case temperatures should not exceed 100
o
C, and the junction
temperature should be no more than 70 to 80% of the rated maximum.
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