Siemens sinamics dcp Operating Instructions Manual page 265

Image 8-72
The curve changes depending on the degree of solar radiation. The figure above shows two
curves for different solar radiation conditions. As the radiation changes, so does the position
of the MPP. This point therefore has to be searched for continuously. This is the task of the
MPP Tracker.
The MPP Tracker operates according to the following principle of operation:
After definition of the ON command, the DCP executes the function "PV array flying restart".
Current is removed from the PV array. As a result, it is taken from no-load voltage to the
permitted voltage range of the DCP.
Now, the current setpoint is increased in small steps and each time the output is measured.
As long as the power is increasing, the current setpoint continues to be increased.
However, if the power drops, the current setpoint is reduced again.
In the settled state, the current setpoint oscillates around the point of maximum power.
The MPP Tracker performs the following individual functions:
● Search interval
● Power calculation
● Current setpoint
● Setting value and setting signal
● Plotting the PV array curve
Search interval:
The search interval specifies at which time intervals (cycles) the current setpoint will be
changed. A standard search interval of 2 seconds is parameterized (p54005).
Power calculation:
The current power is constantly calculated and compared with the power in the previous
cycle.
SINAMICS DCP
Operating Instructions, 05/2016, A5E34382853K
Characteristic curve
Operation
8.16 Technological functions
265