SMA S Technical Description page 174

Glossary SMA Solar Technology AG
Generator
An electrical generator is an electrical machine which converts kinetic or mechanical energy into
electrical energy. Here, not only the electrical generator itself, but also the combustion unit (diesel,
petrol, or gas motor) necessary for the power unit is combined together with the electrical generator
and simplified under the term "generator". This is also described colloquially as a power generator.
Grid-connected System
PV system which is connected to the power supply grid of an external energy supplier.
Invert Mode
See Inverter Operation.
Inverter Mode
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.
Inverters
A device for converting the direct current (DC) from the PV generator into alternating current (AC),
which is necessary for connection of most normal household devices and especially for feeding solar
energy into an existing supply grid. Inverters for PV systems usually include at least one MPP tracker,
store operating data, and monitor the grid connection of the PV system (see also MSD).
Main Cluster
The leading cluster in a multicluster system. The main cluster, for example, has the tasks of voltage and
frequency regulation, grid monitoring, generator control, load management, and control of the
Automatic Switch Box in a backup system.
Maintenance Charge
See Float Charge.
Master
A configuration setting which assigns the leading role in a cluster to a Sunny Island or Sunny Backup
inverter. This stipulates that centralized control and monitoring tasks, which in a cluster must be
performed by just one device (e.g., frequency regulation, battery management, generator control,
and control of the Automatic Switch Box in the Sunny Backup system) are to be performed by this
device. All other inverters of the cluster must be configured so as to leave these tasks to the master,
and to be led by the master (-> slaves). The master is also the device at which the cluster's
configuration, operation, and data recording occurs in a centralized manner.
Maximum Power Point "MPP"
The operating point (defined current/voltage curve) of a PV generator where the maximum power
can be drawn. The actual MMP changes constantly depending, for example, on the level of solar
irradiation and the ambient temperature.
174 SBU2200-TEN083320 Technical Description