AN3392 Datasheet, PDF (7/57 Pages) STMicroelectronics – The SPV1020 is a monolithic DC-DC boost converter designed

AN3392
Application overview
Inverters are complex systems normally providing three functions (DC-DC conversion, DC-
AC conversion and Anti-Islanding) managed by a main controller typically implemented by a
microcontroller or DSP and executing the following actions:
● Anti-Island control, a safety control forcing the system to disconnect from the grid when
it is OFF for maintenance.
● Inverter control, for converting the DC power generated by the PV field to AC power
compatible with the power on the public grid (voltage and current amplitude, frequency
and phase).
● The MPPT (maximum power point tracking) control, allowing the extraction of the
maximum amount of power possible from the PV field in order to maximize the power
sourced to the grid.
A limitation of the architecture in Figure 2 is that the MPPT control performs properly only
when the PV field is uniformly irradiated.
A first evolution of the above architecture is shown in Figure 3 (string-distributed), where the
inverter includes more DC-DC converter sub-blocks, each implementing its own MPPT
algorithm.
Figure 3. Photovoltaic system with multi-string inverter









.
.
.
"Y PASS
DIODES
'RID
)NVERTER
!-V
Even though this architecture provides for a different shadow on each string, it doesn’t solve
the problem of the partial shading on each panel.
Doc ID 018749 Rev 1
7/57