UM1016
System description
Doc ID 18125 Rev 1
15/19
Figure 19.
LCD display showing the closed loop control is in start mode
●
The DC-DC section starts switching by entering the burst mode of operation to charge
the DC intermediate bus up to 380-420 V (hysteresis band). It is suggested to monitor
the DC bus voltage with a multimeter.
●
Once the DC bus voltage is within the correct hysteresis band, the inverter modulation
is enabled and the inverter sinusoidal output voltage is generated
●
If two voltage probes are placed on the inverter output (
), across the capacitor
of the LCL filter and on the grid connector, it is possible to see, on the scope, a
sinusoidal voltage slightly lagging the grid voltage and having a higher peak value
Figure 20.
Voltage probe placement to compare inverter generated voltage and gird
voltage
●
If the grid voltage is in the proper range (190-265 Vac) then the connection relay is
closed automatically. At this point the systems would be grid connected if the coupling
inductor was not disconnected.
●
The LCD display shows the screen shot in
, with the control state update from
start to grid insertion
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