Working Principle - KEHUA TECH SPI-B X2 Series User Manual

2 Overview
 When the inverter works normally, the DC switch must be ON.
 When installation and wiring, the DC switch must be OFF.
 Before maintenance, the DC switch must be OFF for 20 minutes, and measure the voltage of
inner DC busbar by multimeter, only when the voltage is less than 10V, the maintenance can be
done.
When maintenance or wiring, the DC switch must be disconnected.

2.3 Working Principle

PV strings are connected to inverter, and do the max. power point tracking for PV strings through the
two-groups of MPPT circuits inside inverter, and then convert the DC power into the three-phase AC
power through the inverter circuit. It also provides surge protection in DC and AC side, as shown in
Figure2-6.
+
PV1
-
+
PV2
-
+
PV3
-
+
PV4
-
Figure2-6 Working principle diagram
When the DC input (PV) has 2 groups of PV strings, the larger power one should be prior to connect
with PV1, the other should be connected with PV2.
DC/AC
MPPT1
+ +
BUS
- -
MPPT2
+
-
+
BAT
-
10
PV Grid-tied Inverter SPI-B X2 Series (8K-25K)
User Manual
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