Good morning, and I hope you are having a pleasant day!
My name is Lani, and I am a member of the Australian National University Solar Racing team. We are a group of students working to design, build and race a solar powered car through the Australian desert as part of the Bridgestone World Solar Challenge. Through competing in the Challenger class, we create a platform to develop cutting-edge designs and sustainable technologies, and test them in real-world environments.
My role on the team is to optimise the power output of our custom solar array, which provides the only energy that the car is allowed to use for the duration of the race. Historically, our team has used active bypass diodes to maximise power output and minimise hot-spotting of mismatched solar cells within the same string. However, I have been looking into alternate options and think that the MAX20801 cell-string optimiser IC chip developed by your company is extremely interesting. I was hoping that you could provide some guidance on how could I model this part in LTSPICE or using a similar software? I am interested in comparing the maximum power output of our solar strings using the MAX20801 IC chip vs our existing active bypass diodes at different levels of current mismatch between solar cells.
The solar array consists of 3 strings, which each run at approximately 82V under standard test conditions. Bypass diodes/ MAX20801 chips could be wired as often as necessary. Each string is connected to a master MPPT.
I tried simulating the function of the MAX20801 by doing the following:
1. Find the voltage at the maximum power point per 10 solar cells in the string (value was always within input voltage operating range of MAX20801 chip).
2. Place a voltage source in series with the solar cells, that ran at the voltage found in step 1.
3. Wire each of these voltage sources in series with each other
4. Add another voltage source that was programmed to sweep voltages from 0 - 85V, to produce an IV curve (to simulate the function of the master MPPT).
This gave an error that said "Voltage source V2 is in a loop involving voltage source V1 and other voltage sources and/or inductors making an over-defined circuit matrix. You will need to correct the circuit or add some series resistance."
Here is an example with 2 solar modules (each consisting of 10 cells).
Thank you for your help.
