https://en.wikipedia.org/wiki/Theory_of_solar_cells#Equivalent_circuit_of_a_solar_cell
This circuit is very easy to create with discrete circuit components. To get higher panel voltage, we can just connect a bunch of these circuits in series, or just put a bunch of diodes in series and adjust the other values as appropriate.
Let’s try and come up with a reasonable design a component selection for it.
Parameter | Component | Value | Reason |
|---|---|---|---|
IL | Power supply in CC mode | 10A min. | Isc of solar cells is about 7A. If the power supply is able to provide 10A then we are able to hit all operation points. |
ID | Diodes in series | Vf of diode string = 30V | 30V = max input voltage for Nomura MPPTs. We can connect others in series if we want to expand and test at higher voltages for other MPPTs. |
Rsh | Resistor | 100k Ohms or so. | Guess for shunt resistances in solar cell |
Rs | Resistor | 0.2 Ohms or so. | Guess for connection resistances in solar panel |
10A 30V programmable supply: https://www.digikey.ca/en/products/detail/b-k-precision/9103/7056819
We have one of these in the bay already.
Diode string - 30 of these in series should be reasonable: https://www.digikey.ca/en/products/detail/vishay-general-semiconductor-diodes-division/VS-E4TU2006FP-N3/8269295
Heatsink - diodes will get hot. Need a heatsink and fan to keep them cool. Something like this and a few fans should be good: https://www.digikey.ca/en/products/detail/advanced-thermal-solutions-inc/ATS-EXL76-300-R1/5848414
Or a few of these: https://www.amazon.ca/Awxlumv-Amplifier-Transistor-Semiconductor-180mm69mm36mm/dp/B07THL4Z12/ref=sr_1_9?crid=389K27BX237G&keywords=aluminum+heatsink&qid=1667254617&qu=eyJxc2MiOiI1LjQ4IiwicXNhIjoiNS4wNCIsInFzcCI6IjQuNTMifQ%3D%3D&sprefix=aluminum+heatsink%2Caps%2C75&sr=8-9
Diode Temp rise
1.4V (diode datasheet) * 10A = 14W.
14W * 3C/W (diode datasheet) = 52C rise.
If we keep the heatsink under 100C, the diodes should be fine. A few fans for lots of forced air should be able to do this.
A few forum threads on building these:
https://diysolarforum.com/threads/bench-power-supply-to-simulate-solar-panel.11564/page-2