Wit 4-15K-Hu Operating Principles - Growatt WIT HU Series User Manual

3.5 WIT 4-15K-HU Operating Principles

1) The hybrid inverter receives DC inputs from PV strings which go through the
MPPT routes. The DC power is then converted into AC power through the
inverter circuit to power the loads and feed power into the grid;
2) The PV strings can supply power to charge the battery through the MPPT routes;
3) Convert battery power to AC power supplies for the loads and feeding to the
grid;
4) Charge the battery from the grid through a rectifier circuit;
5) Convert the DC power from PV strings and the battery power into AC power
through the inverter circuit to power critical loads;
6) When the GEN port is connected to the generator and set to the GEN mode, the
generator can supply power to the loads or charge the battery;
7) When the GEN port is connected to loads and set to "Smart Load" mode; during
on-grid operation, it will supply grid power to the loads connected via the GEN
port; during off-grid operation, the power supply to smart loads will be cut off
when the battery SOC is below 50%.
8) When the GEN port is connected to the PV inverter and set to "AC Couple" mode,
during on-grid operation, the PV inverter will be connected to the grid and
output power; during off-grid operation, the PV inverter will remain connected
and generating power together with the WIT inverter.
NOTE: WIT 4-15K-HU models have 2 MPPT routes.
+ + +
- - -
EMI
PV1
MPPT1
+
-
+
EMI MPPT2
PV2
-
PV Switch
DC SPD
Battery+ +
EMI EMI Buck-
Battery- -
DC MOV
Fig 3.10 WIT 4-15K-HU Grid-connected conceptual diagram
11
DC/AC
DC Link
BOOST
R
S
T
N
R
S
GRID
EMI
T
N
AC SPD
R
S
LOAD
T
N
R
GEN/
S
Smart Load/
T
AC couple
N
GEN Relay
AC SPD