Siemens SINAMICS G130 Engineering Manual page 31

Fundamental Principles and System Description
Engineering Information
Dips in range B are, therefore, only permissible when the supply of the auxiliaries with 230 V is done via a secure,
external source. It must also be taken into consideration that the DC link voltage and the drive power decrease in
proportion to the magnitude of the supply voltage dip.
Range C
Range C comprises very short supply voltage dips of any magnitude, the duration of which is up to 5 ms. During this
time, the current required by the load is mainly delivered by the DC link capacitors, thus causing the DC link voltage
to decrease. Due to the extremely short duration, the DC link voltage does not reach the under-voltage trip level,
even at 100 % load. The auxiliaries supplied with 230 V also remain in operation.
Dips in range C are, therefore, as a result of the extremely short duration, permissible without restrictions.
Range D
Range D comprises very short supply voltage dips of any magnitude, the duration of which is up to 10 ms. During this
time, the current required by the load is mainly delivered by the DC link capacitors, thus causing the DC link voltage
to decrease. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged
more slowly than in range C. Therefore, the drive can be operated with a maximum load of 50 %. Due to the relatively
short duration, it can be assumed that the auxiliaries supplied with 230 V will remain in operation.
Dips in range D are, therefore, as a result of the very short duration, permissible, as long as the drive is operating at
partial load with a maximum of 50 % load.
Range E
Range E comprises short supply voltage dips of any magnitude, the duration of which is up to 50 ms. During this
time, the current required by the load is mainly delivered by the DC link capacitors, whereby the DC link voltage
decreases. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged
more slowly than in range D. Therefore, the drive can only be operated with no load. The auxiliaries, which are
supplied with 230 V directly from the supply via the internal transformer, do not remain in operation.
Dips in Range E are, therefore, only permissible if the auxiliaries are supplied from a secure, external supply and the
drive is in no-load operation.
Range F
Range F comprises supply voltage dips, the magnitude and duration of which is so large, that, independently of the
load, a fault trip due to under-voltage in the DC link cannot be avoided.
Dips in range F are, therefore, not permissible.
Summary of the drive behaviour during supply voltage dips
If one considers the behaviour of the unregulated and regulated SINAMICS Infeeds and also reflects upon the typical
distribution of supply voltage dips as shown in the diagram in the section "Suppy voltage variations and supply
voltage dips", the following conclusions can be drawn.
Extremely large dips as those in the ranges C to E, during which the supply voltage dips to almost zero and the
energy flow from the supply to the DC link is essentially interrupted, can only be tolerated, independently from the
kind of Infeed, for a time period of approximately 5 ms to a maximum of 50 ms, depending on the load condition,
because the energy stored in the DC link capacitors is very low. However, dips of such magnitude and duration very
rarely occur in practice.
Longer dips of more than 50 ms can only be tolerated if the energy flow from the supply to the DC link is maintained.
With the line-commutated, unregulated Infeeds, Basic Infeed and Smart Infeed, this is only the case if the supply
voltage dips not lower than on values of approx. 75 % of the nominal supply voltage V (ranges A and B). Without an
N
external auxiliary supply, 50 % of all typical supply voltage dips can be dealt with (range A), with an external auxiliary
supply, this increases to 70 % (ranges A and B).
With the self-commutated, regulated Infeed, SINAMICS Active Infeed, the energy flow from the supply to the DC link
is maintained even if the supply voltage dips to around 50 % of the nominal supply voltage (ranges A and B). Without
an external auxiliary supply, 50 % of all typical supply voltage dips can be dealt with as in the case with unregulated
Infeeds (range A). With an external auxiliary supply, however, this increases to almost 100 % (ranges A and B). Thus
the regulated SINAMICS Active Infeed offers clear advantages in comparison with the unregulated Basic and Smart
Infeed for supplies which often experience relatively large voltage dips.
SINAMICS Engineering Manual - May 2008
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