Operating principle

Depending on the configuration, 1 or 2 "synchronizing contactors" are used to disconnect or connect an energy storage unit from or to the DC link. These contactors must be installed in the supply cable to the minus or plus pole.

If the load-break switch is opened, e.g. to perform service work on the DC link, the MOVI-C® CONTROLLER automatically opens the synchronizing contactors. The storage unit can now be switched on again via the load-break switch when the service work has been completed. The final connection via the synchronizing contactors can be taken over by the "DC synchronization" operating mode. In this case, the DC link voltage is initially adjusted to the storage voltage to prevent any current flows during the switching process. The contactors are then closed so that the storage unit is now permanently connected to the DC link.

The operating mode can only be activated if the energy storage unit is explicitly configured as separable in the configuration of the software module and the "Active DC synchronization" option is selected as the "Storage connection variant". If the energy storage unit is permanently installed and therefore cannot be separated from the DC link, the operating mode cannot be used.

The operating mode checks the switching state of the storage unit using test procedures. The energy storage status reported to the user can have the following states:

  • Energy storage unit connected: The energy storage is connected to the DC link. The result is reliable because a charge test has been performed.
  • Energy storage unit not connected: The energy storage unit is not connected to the DC link. The result is reliable because a charge test has been performed.
  • State of energy storage unit unknown: The energy storage unit is either connected or disconnected. No charge test has been carried out, therefore the switching state of the contactors cannot be reliably indicated.

INFORMATION

In order to be able to connect energy storage units with any state of charge, the minimum voltage of the side on which the energy storage unit is located (parameter "Application limit – Minimum voltage A-side" or "Application limit – Minimum voltage B-side") must be set to 0 V in the State of charge control configuration menu.

A possible connection topology is illustrated and symbolized in the following figure:

2 wiring variants are supported. One variant with a contactor in the negative line (negative contactor) and one variant in which another contactor is installed in the positive line in addition to the negative contactor. This means that the storage unit can be automatically electrically isolated.

The additional contactor is especially necessary if the energy storage unit is to be automatically disconnected from the DC link at all poles in the event of a fault (e.g. if a modular residual current device is installed).