Brief Notes/Background information on MPPT Task
11 segments - number on sides give the cell counts
as long as mppt is less then output it will boost
check the datasheet to know the turning angle for pot
Pot 1 → Will describe the reference for boost
Pot 2 → Uses the reference but is the boost factor
Mppt per segment of array
18-33Volts (per unit) (should be good based on MPPT)
We don’t want all in series because it is worse bang for buck
Current configuration 5 in series parallel with 6 in series
All in series because the output is input for next
Same reference all mppts need to be above potential battery can be at (98-154V) Rount to 160 so that the 5 mppts can cover 160v and the other 6 can do 160V.
Configure mppt by turning pot 1 and pot 2 (basically look through the documentation to figure out how to turn the pots to get to these voltages)
ask micah black about nominal volts
megawatt peak of 3.72Watts nominal voltage is about 0.6V
max input is about 29V which means mppt will always be boosting
Spy will tell us voltages and temperature
ME1 cells (ask what type of cells we are using)
TO DO
verify output nums with micah black and boosting volts
Ask Catherine or Michael Shiozaki about cell nominal and any data sheets (a little confused about this)
figure out from data sheet the optimal pot 1 and pot 2 angle for expected out
Talk to Josh about about testing mppt out with power supply by varying it based on expected volt to reference of cells
Documentation/Progress of task
Confirmed Numbers with Michar (~150 is good)
Have data sheets (still to look through for cells)
Min 1.1 to 1.15 boost
Pot has 11 turns
To look through the svn102 chip stuff
*Currently a little confused as I’m not sure how to figure out how much to turn the pot. We know that the right array should be boosted to 32V and the left to 26. The nomura does a minimum boost of 1.1 to 1.15 boost. I checked the data sheets but couldn’t find a specific ratio for effect of changing the potWork in progress
What needs to be done
Find the angles the Nomura MPPT needs to be set at so that it can boost the voltage from the array to the necessary amount
The left array will have six nomuras. To ensure that the voltage is 160V each should be boosting to about 26.7V
The right array will have five nomuras. They need to be boosted to about 32
Connecting The Nomura
Connect the positive input from the voltage source to PV_IN[+] and connect the negative input from the voltage source to PV_IN[-]. Then connect PV_OUT[+] as the positive output and PV_OUT[-] for the negative output. These are all the connections that need to be made for the Nomura. See the image below for the connections
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Settings before using the Nomura (Directly from the instruction manual. Attached in this page and can be found in the Further Normura Testing page)
Check voltage between "P2" terminal and "GND PV_IN[-]". and adjust voltage to reach 1.25V(+/-0.02) by adjusting screw "VR1".
Note: it is very convenience when check the “P2” voltage if you add small wire to “P2” terminal.
You can adjust output voltage by adjusting potentiometer screw "VR2". But please make sure thatthis is boosting MPPT. And it need minimum 1.1-1.15 times Boosting require for have trucking. Incase less than 1.1-1.15, it will be through mode.
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Test 1. Trial and Error
The first test that needs to done is to find out how much the nomuras can actually boost with relation to the angle of the potentiometer.
This test can be done with a variable power supply, multimeter, and a nomura. The Nomura needs an input voltage between 10-30V, so select one from that range. Based on the datasheet for the cells, which can be between 18-33V, it would be best if say 20V was being tested. Once that is done, change the position of the second potentiometer (VR2) and measure the output voltage, recording it and how much the pot was changed by.
Test 2. Actual Solar Cells
If the solar cells are available it would be beneficial to be able to connect a solar cell to the nomura to ensure that the angles that are used works. Once the voltage that the array actually provides can be confirmed, setting up test cases with these values would be extremely beneficial as they would give the most amount of information regarding whether the angels determined work.