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Building and Testing the Circuit
Before jumping into a purchase to make one of these, we can make a small model of one with regular diodes and test the IV curve. Just need to make sure to keep the tests quick so the diodes don’t heat up too much.
I made the circuit with the following parts/parameters:
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All tests were done with a python script available here: https://github.com/mbA2D/Test_Equipment_Control
I used Eload_cv_sweep.py to control the e-load and do all the measurements, and used Eload_cv_sweep_graph.py to make the graphs.
Test 1
Current Source: Digital power supply set to 1V, 0.1A (low current since I didn’t want to burn up the diode. Larger currents later)
Diode: Generic 10A-rated silicon diode (1 diode only for the first test).
RSH: 10k 1/8W resistor
RS: 5A glass fuse acting as the series resistance (about 30mOhm resistance).
I tested with an e-load connected to the output, set in constant voltage mode. I swept the constant voltage from 0 to 1.2V while measuring the voltage and current and plotted the following graph:
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Test 2
Current Source: Digital power supply set to 10V, 0.5A
Diode: Generic 10A-rated silicon diode (10 diodes in series).
RSH: 10k 1/8W resistor
RS: 5A glass fuse acting as the series resistance (about 30mOhm resistance).
I tested with an e-load connected to the output, set in constant voltage mode. I swept the constant voltage from 0 to 10V while measuring the voltage and current and plotted the following graph:
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Test Results:
These tests clearly show a maximum power point is reached with a smooth curve to the top of it, in contrast to the IV curve of a power supply that has a sharp drop at the MPP. This simulates solar panels very well and can be used to thoroughly test the MPPTs, removing the solar panels from the equation.