| Description |
Photovoltaic panels are nonlinear electric power sources whose
output voltage and power vary with the current demanded by the
load, temperature and age of the cells. There are a few commercial
“I x V tracers” for plotting the I x V curves of solar panels/arrays.
They employ variable/controllable impedances that can be
essentially of three types: Linear resistance (MOSFET), switched
DC-DC converters and inductor/capacitor with mechanical switch.
The sensed voltage, current, solar irradiance and temperature are to
be sensed and stored in a way that allows the plotting of I x V
curve accurately and with reduced data storage requirements. A
microcontroller is typically employed for controlling the variable
impedance and collecting, storing and/or displaying the sensed
quantities and curve.
The objective of this project is the analysis, design and
implementation of low-cost I x V tracers. The trade-offs between a
simple variable impedance and a complex algorithm for sampling
and storing the sensed quantities are to be considered. Suitable
approaches for displaying the results/plots and transferring data to
a memory stick, computer or the internet/cloud are to be
developed. Working prototypes implemented on a printed circuit
board (PCB) should be presented at the conclusion of the project.
|