Peak Power Tracker Project

IV curves for any solar panel; (E0004X.pdf) the graph will show that the curves
change with the amount of light and the temperature of the panel. They also change for
each individual solar panel. As the curves change, the MPP changes for the different
temperatures and light levels. If the MPP changes, the conversion ratio of the input
voltage to output voltage of DC/DC converter must also change to keep the solar panel
voltage at the MPP.
The Peak Power Tracker uses an iterative approach to finding this constantly
changing MPP. I call this iterative method a hill climbing algorithm. Examining the
graph of the solar panel watts (Fig. 3), it looks like a hill with the MPP at the summit.
The PPT (Fig. 4) uses a microprocessor to measure the watts generated by the solar
panel. It then controls the conversion ratio of DC/DC converter to implement the hill
climbing algorithm. The software in the microprocessor works like this:
Increase the conversion ratio of the DC/DC converter.
Measure the solar panel watts.
If the solar panel watts are greater than the last measurement,
Then it is climbing the front of hill, loop back and do it again.
Else if watts are less than the last time measurement,
Then it is on the back side of the hill, decrease the conversion ratio and
loop back to try again.
This hill climbing algorithm occurs about once a second in the PPT and it does a good
job of keeping the solar panel operating at its
Maximum Power Point.