CARLO GAVAZZI ISMG 315, User Manual

Page: 46 / 91

36
3. Operation
3.1 Overview
The control electronics will be active as soon as the DC (PV) voltage reaches
“minimum MPPT” voltage point which is around 200VDC. The ISMG3 inverter is
then powered up and will show “Illumination” on the LCD, complete the system
initialization and wait for the DC voltage to reach the “PV start” voltage point
which is 400VDC. When the DC voltage reaches the “PV start” voltage point, the
inverter will enter “Checking” mode and then go on-line with the mains grid
(“Grid/MPP” mode) if all necessary conditions for grid connection are checked
and fulfilled. If the DC input voltage falls below the “pre-set threshold” point, the
inverter will shut off its output AC power and go back to “Illumination Low” mode
providing the DC voltage remains above the minimum MPPT voltage point. When
the DC voltage goes under the “minimum MPPT” voltage point, the inverter will
shut down itself.
There are five main operating modes described in detail below.
Illumination:
When the DC input voltage goes above the “minimum MPPT”
voltage point, the inverter is powered up, and enters the
system initialization procedure with “Illumination” displayed
on the LCD. In this operation mode, the inverter sets the
initial values, runs diagnostics, and detects all parameters
that will be stored for future use. This stage takes only a few
seconds and then the inverter will wait until the DC input
voltage reaches the “PV start” voltage point to enter the
“Checking” mode.