Siemens SINAMICS G130 Engineering Manual page 70

Fundamental Principles and System Description
Engineering Information
Redundant line supply concepts with the SINAMICS Smart Infeed
With the line-commutated unregulated SINAMICS Smart Infeed only variant 2 can be used.
Variant 2 with SINAMICS Smart Infeed, boundary conditions to be observed:
•
Each Smart Line Module requires a line reactor with a short-circuit voltage of 4 %.
•
If the three-winding transformer corresponds to the specification in the section "Transformers", subsection
"Three-winding transformers", and it can be accepted that the common DC link is operating with half the
power when a Smart Line Module fails, each Smart Line Module can be selected for half the input current
taking into account a current derating of 7.5 % related to the rated current, as with the 12-pulse, parallel
connection of Smart Line Modules. If the full infeed power is required when a Smart Line Module fails, each
of the two Smart Line Modules and their associated transformer windings must be dimensioned in line with
the full power required for the DC link.
•
Each Smart Line Module must be able to precharge the complete common DC link capacitance.
Redundant line supply concepts with SINAMICS Active Infeed (master-slave configuration)
The regulated SINAMICS Active Infeed allows variants 2 and 3 to be realized. The individual Active Infeeds, which
comprise an Active Interface Module AIM and an Active Line Module ALM, must be configured and set up so that
they are completely autonomous. They must operat in master-slave configuration. An autonomous setup means:
•
Each Active Infeed must have a separate Control Unit CU320.
•
The Control Unit CU320 for each of the Active Infeeds must only control the Active Infeed to which it is
assigned.
•
The Motor Modules on the DC link must be operated completely independently from the Infeed Modules on
a separate Control Unit CU320 or several separate Control Units CU320.
The master infeed is operating in voltage control mode and regulates the DC link voltage V
slave infeed(s) is/are operating in current control mode, whereby one master infeed is required and not more than 3
slave infeeds are permissible.
The current setpoint for the slave infeed(s) can be transferred from the master infeed to the slave infeed(s) via
PROFIBUS DP V2 slave-to-slave communication when a higher-level control system is used or via analog channels,
when Terminal Modules TM31 are used. For more information about communication and parameterization, see the
SINAMICS S120 Function Manual 1.
If a slave infeed fails, the master infeed and any other slave infeed will continue operation. If a master infeed fails, a
slave infeed must switch over from slave operation in current control mode to master operation in voltage control
mode. This can be done during operation (i.e. without the need for any downtime).
Note:
Master-slave configuration of SINAMICS S120 Active Infeeds will be available with firmware version V2.6 from
autumn 2008.
Variant 2 with Active Infeed (master-slave configuration); boundary conditions to be observed:
•
Both of the two Active Infeeds (master and slave) must be electrically isolated on the line side to prevent
circulating currents that may otherwise occur between the systems as a result of autonomous,
unsynchronized operation with two independent Control Units. This electrical isolation, which is absolutely
essential, is ensured by means of the three-winding transformer.
Depending on the type of supply system required (grounded TN supply system or non-grounded IT supply
system), the star point of the star winding supplying the master infeed can be grounded (TN supply system)
or remain open (IT supply system). With respect to voltage loads on the DC link and on the motor windings
to ground, however, operation with a non-grounded IT supply system is preferable. The winding for the slave
infeed must remain non-grounded in all cases.
SINAMICS Engineering Manual – May 2008
70/396
© Siemens AG
of the DC link, while the
DC