SMA Sunny Island 5048 Installation Instructions Manual page 165

SMA
Technologie AG Glossary
power from a solar power system being fed into an external power grid when the ex-
ternal power generator is not functioning. In the Sunny Boy/Sunny Mini Central, this
function is assumed by the "SMA grid guard Version 2".
Inverters
A device for converting the direct current (DC) from the PV generator into alternating
current (AC), which is used by most normal household devices and especially for fee-
ding energy into an existing supply grid. Inverters for PV systems usually include one or
more MPP trackers, store operating data and monitor the grid connections of the PV
system (see also MSD).
Inverter mode
See Inverter operation
Inverter operation
Operating mode of a battery inverter where it supplies the stand-alone grid from the
battery energy. In this operating mode, the battery inverter is especially responsible for
the control of frequency and voltage in the stand-alone grid.
Maximum Power Point "MPP"
The working point (current/voltage characteristic curve) of a PV generator where the
maximum power can be drawn. The actual MMP changes constantly depending (e.g.)
on the level of solar irradiation and the ambient temperature.
MPP tracker
Regulation of the power drawn so that a PV generator remains as close as possible to
the MPP. This working point varies with the solar irradiation and the temperature con-
ditions of the modules. MPP tracking optimizes the extraction of electrical power and is
a feature of inverters and charge controllers.
MSD
See Independent disconnection device
Multi-string inverter
An inverter that combines the advantages of several string inverters (separate MPP tra-
cking of individual strings) and a central inverter (lower performance specific costs).
NiCd
Nickel/Cadmium battery, contains Nickel, Cadmium, and potassium hydroxide as the
electrolyte. They require a significantly higher charging voltage, have a lower level of
efficiency and are significantly more expensive than lead acid batteries. Their robust-
ness, cycle resistance and low-temperature capabilities allow them to be used in certain
special applications.
Technical Description SI5048-11:EE4206 Seite 165