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EMC compliance of the complete installation
Note: ABB has not verified that the EMC requirements are fulfilled with external energy
storage and its cabling. The EMC compliance of the complete installation must be considered
by the customer (or the system integrator).
Parallel connection
It is possible to connect multiple DC/DC converter units in parallel. In the parallel connection,
both the inputs and the outputs of the units must be connected together. The inputs are
connected through the common DC bus of the multidrive as standard. The outputs (ES+ to
ES+, ES- to ES-) must be connected together at the energy storage end by the customer
(or the system integrator).
The customer (or the system integrator) must make sure that the load sharing is even
between the parallel units. Depending on the case, this may require additional parameter
tuning in DC/DC converter control programs of both units:
•
If the operating mode selection (197.13) is Power or Add: The load between the units
is inherently shared according to the power or current references. No additional settings
are required.
•
If the operating mode selection (197.13) is DC voltage: Tune the load sharing using the
droop control function.
•
Master/follower operation of the parallel units: The control program does not support
the master/follower link between several units. However, it is possible to implement the
Master/follower operation with an external PLC. In that case, one DC/DC converter unit,
the master unit, operates in the DC voltage control mode and the other unit(s) in power
control mode. The external PLC reads the output current reference of the master unit,
and uses it as the current reference of the follower units.
The load sharing during an overvoltage or undervoltage control of the DC/DC converter can
require tuning of the DC voltage offset value between the parallel units. See the firmware
manual for details.
The customer (or the system integrator) must pay special attention to the protection concept
in case of parallel units. The protection must operate reliably in all possible fault cases.
Guidelines for planning electrical installation 57
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