Ge CS300 User Manual download pdf (Page 17)

CS300

——————— Half controlled power supply for inverter DC-Link ————————

)

L*2

(

C*L

Having as a unit of measure the “L” inductance in Henry, the “C” capacitor in Farad and the “R” resistance in

Ohm, according to the above mentioned data:

= 1331.21 rad/S

L*2

=α

from which:

= 357.14

from which: t

= 0.00117 s

( t

states the time needed by the current to reach its maximum value )

4) the peak current can be calculated with the following formula:

from which : I

= 572.3A

It is obvious that considering a 70V discharge of the DC-LINK (3-mS mains dip) the current is too high for the

converter. As a consequence, it is necessary to consider a lower voltage reduction (corresponding to a shorter

mains dip). Therefore, with a voltage reduction of 35V (1.5-mS mains dip), the new value will be:

= 286.1 A

Such value meets the needing of both the converter (which for short periods is able to bear a current value two

times the rated one) and the inductance, whose saturation current is higher than 300A.

Table of S1.1-4 Delay for thyristor switching off during mains dip.

1 2 ... 12 13 14 15 16 17 18 19 20 21 22 ... 27 28

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Ge CS300 User Manual Page 17