Backfeed Current - Power One AURORA PVI-OUTD-US Series Installation And Operator's Manual

Installation and Operator's Manual
(PVI-3.0/3.6/4.2-OUTD-x-US Rev: 2.1)
8.5 Input Source Backfeed Current
PVI-4.2(3.6, 3.0)-OUTD-x-US Grid Tied Inverters are provided with two separate and
consecutive power stages:
•
Booster Stage (DC-DC converter) connected to DC Input Terminals.
•
Inverter Stage (DC-AC converter) connected to AC Output Grid Terminals.
The Booster Stage is provided with forward diodes that allows the current (power)
flow only from DC Input terminals towards Inverter (Output) Stage.
In case of any fault on Inverter Stage, these diodes avoid any back-feed current
phenomena towards input terminals.
In case of fault of the forward diode, the corresponding booster MOSfet goes
immediately and permanently in short circuit state and it avoids any current
propagation form output to input terminals.
Abnormal Fault tests conducted during UL1741 qualification show also that these type
of faults produce the opening of internal grid disconnect relays and cause the external
AC CB protection devices to trip, preventing any power flow from the grid.
In conclusion for PVI-4.2(3.6, 3.0)-OUTD-x-US-y models it is not possible to have
any single fault responsible of Input source back-feed current flow. For these models
the Back-feed current into DC Source is negligible.
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