Frequency-Shift Power Control (Fspc) - SMA SUNNY ISLAND 4548-US Operating Manual

17 PV Inverters
No. Parameters
5 Fac-max+
Upper range where the Sunny Boy is active,
based on f
0
6 dFac-Max
Max. rate of change
7 Fac-start delta
Frequency increase in relation to f
point the power adjustment via frequency begins
8 Fac-Limit delta
Frequency increase based on f
power control via frequency ends. The power of
the Sunny Boy at this point is 0 W.
* V = 208 V/240 V/277 V
AC Nom
This completes the stand-alone grid parameter settings for the Sunny Boy.

17.5 Frequency-Shift Power Control (FSPC)

This section describes the operating principles of the "power adjustment via frequency" (Frequency
Shift Power Control - FSPC).
If Sunny Boy inverters are connected to the AC side of the off-grid system, the Sunny Island must be
able to limit their output power. This situation can occur when, e.g. the Sunny Island battery is fully
charged and the (solar) power available from the PV array exceeds the power required by the
connected loads.
To prevent the excess energy from overcharging the battery, the Sunny Island 4548-US / 6048-US
recognizes this situation and changes the frequency at the AC output. This frequency adjustment is
analyzed by the Sunny Boy. As soon as the power frequency increases and exceeds a defined value
"f Start Delta", the Sunny Boy limits its power accordingly.
AC
This function is shown in the following figure:
154 SI4548-6048-US-BE-en-21
Short descr.
Hz
Hz/s
Hz
, at which
0
Hz
, where the
0
SMA Solar Technology America LLC
Value
+3.0 (starting from the
base frequency f
4
1 (starting from the
base frequency f
2 (starting from the
base frequency f
Operating Manual
)
0
)
0
)
0