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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