SMA Sunny Island 4548-US, Техническое описание

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SMA America, LLC 23 Glossary
Technical description SI4548_6048-US-TB_en-13 235
Inverter mode
Operating mode of a battery inverter where it supplies the stand-alone grid from the battery energy.
In this operating mode, the off-grid inverter is especially responsible for the control of frequency and
voltage in the stand-alone grid.
Maximum Power Point "MPP"
The operating point (current/voltage characteristic curve) of a PV array where the maximum power
can be drawn. The actual MPP changes constantly depending e.g. on the level of solar irradiation
and the temperature.
MPP tracker
Regulation of the power drawn so that a PV field remains as close as possible to the MPP. This
operating point varies with the solar irradiation and the temperature conditions of the modules. MPP
tracking optimizes the extraction of electrical power and is a feature of inverters and charge
controllers.
MSD
See Automatic disconnection unit
Multi-string inverter
An inverter that combines the advantages of several string inverters (separate MPP tracking 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 robustness, cycle resistance and low temperature
capabilities allow them to be used in certain special applications.
Off-grid inverter
See Battery power converter
Overload capacity
The overload capacity of an inverter describes its ability to supply short-term (seconds or minutes)
excessive loads that can be significantly higher than the nominal power of battery inverters. The
overload capacity is necessary in order to be able to also start electronic machines that have a
nominal power similar to the nominal power of the inverter in the stand-alone grid, since these
machines typically need six times more current during start up in relation to the nominal current.