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In Polysun, batteries are equipped with an automatic controller as a standard. If necessary, the battery may also be controlled by means of the available programmable controller.

The controller works based on a calculation of the system’s net power \(P_{n}(t) = \ I_{generated} – I_{consumed}\), with I= power.

Automatic controllers work on this basic principle: the battery is charged when enough self-generated power is available and discharged as soon as a power deficit occurs. It is never charged from the grid, unless under one of the following conditions:

  • The battery’s state of charge falls below an SOE_H2 threshold (-0.05 by default). In this case, boost charging occurs with 0.25 times the nominal charging power, until the battery reaches its minimum state of charge. A common cause of this case is a high self-discharge or high peripheral consumption in combination with long periods without charging.
  • The battery peripherals’ or battery inverter’s AC consumption is not met by the electricity production.
  • The battery’s stationary control deviation is not met by the electricity production.

Description of an automatic controller:

  1. When the system generates an amount of power in excess of what is consumed  (Pn(t) > 0) the following charge pattern applies:
    1. Charge battery with maximum possible, available power as long as it can be charged.
      Pch(t)=min[Pnt, Pch,maxt]
    2. Feed remaining power into the grid.
  2. When the system consumes more power than it generates (Pn(t) < 0) the following discharge pattern applies:
    1. Discharge battery to maximum possible extent as long as it can be discharged.
      Pdis(t)=min[|Pnt|, Pdis,maxt]
    2. Draw the remaining power from the grid.

The battery offers two inputs for the programmable controller:

Table: Input parameters for the programmable controller

Control modeShows how the battery is controlled0: automatic controller (default value)
1: controlled battery power is used
Controlled powerBattery power may be set.> 0: the battery is charged, value in W
<= 0: the battery is discharged, value in W

Template 50h provides an example of explicit battery control.