MPPT for wind turbine

by GoVertical0017 on Wed Dec 12, 2012 9:08 pm

Greetings, I am working on a MPPT controller for a wind turbine. I have the DC to DC converter working and I am able to manually adjust the duty cycle of the buck converter from 10 to 50 percent.

The next step of the project is to add a micro to control the duty cycle of buck converter. This is where I need help. I have to read the voltage and current at the input and output. I am using a Arduino UNO.

Max voltage is 400 Vdc at the input of the buck converter.
Buck converter max current is 20 amps.

Any help received will be greatly appreciated. What methods should I use for reading the voltage and current?
Attachments
FOD3180testCircuitConcept.JPG
Buck converter with manual control for duty cycle
FOD3180testCircuitConcept.JPG (113.96 KiB) Viewed 2057 times
bottom.jpg
Vertical Axis Wind Turbine
bottom.jpg (116.7 KiB) Viewed 2057 times
DSCN2142.jpg
F&P PMA
DSCN2142.jpg (118.67 KiB) Viewed 2057 times
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Re: MPPT for wind turbine

by GoVertical0017 on Wed Dec 12, 2012 9:45 pm

Hi, photos of buck converter circuit for project.

The buck converter is four 5 amp DC to DC converters connected in parallel. I am using the IRF840 mosfet. I am using a F&P axial flux motor as a 3 phase permanent magnet alternator that generates about 1 volt per RPM. Because it is possible to generate a very high voltage I have included a over voltage protection circuit.

Requesting suggestions for sensing current and reading voltage at the input and output that can interface with a UNO.
Attachments
OVPforBuckInputVer2.JPG
over voltage protection circuit
OVPforBuckInputVer2.JPG (44.87 KiB) Viewed 2034 times
FOURparallelFOD3180testCircuitConcept.jpg
buck converter
FOURparallelFOD3180testCircuitConcept.jpg (80.99 KiB) Viewed 2048 times
BuckConverter&controller.jpg
Buck converter circuit
BuckConverter&controller.jpg (127.86 KiB) Viewed 2048 times
Last edited by GoVertical0017 on Wed Dec 12, 2012 10:50 pm, edited 1 time in total.
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Re: MPPT for wind turbine

by john444 on Wed Dec 12, 2012 10:06 pm

Hi GoV,

Your VAT looks great.

I was going to suggest the Adafruit INA219 High Side DC Current Sensor.
The 20-A will not be a problem with a shunt-resistor change.
However, it will not be usable unless you were to use it on the 12-V side
of your circuit.

At 400-V you need good isolation! Maybe you would want to consider
sensing on the AC side of the alternator:
A current transformer or Hall effect will provide the Amp measurement.
A voltage-transformer for voltage.
These will provide the isolation you need and you can work with signal levels
an Arduino can handle. Especially since you do not need milli-Sec speeds.

Good Luck, John
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Re: MPPT for wind turbine

by john444 on Wed Dec 12, 2012 10:11 pm

GoV,

I see you posted again before I finished composing my response to your
first post. :)

Why 4 buck-converters? Why not just one capable of 20-A?

John
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Re: MPPT for wind turbine

by GoVertical0017 on Wed Dec 12, 2012 11:01 pm

john444 wrote:GoV,

I see you posted again before I finished composing my response to your
first post. :)

Why 4 buck-converters? Why not just one capable of 20-A?

John

Hi, I tried paralleling the mosfets and at higher amperage the board became hot, sometimes to hot. A 20 inductor is to expensive for the project. I have had very good results with the 5 amp versions, it stays cool. The max current for each board 6 amps but I am limiting the project to 15 amps total.

This a first time attempting at this kind of project and I am searching for other project that read voltage and sense current using a UNO. Thank you for the suggestions.
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Re: MPPT for wind turbine

by john444 on Fri Dec 14, 2012 11:47 am

GoV,

GoVertical0017 wrote:I tried paralleling the mosfets and at higher amperage the board became hot

If each FET had it's own driver, paralleling should have worked fine.

GoVertical0017 wrote:A 20 inductor is to expensive

Is it 4x as expensive as four 5-A inductors?

GoVertical0017 wrote:I have had very good results with the 5 amp versions, it stays cool.

That is good. However, sometimes units conflict with each other. If yours don't you are good.

What do you think? measure high-side AC or low-side DC?

John
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Re: MPPT for wind turbine

by GoVertical0017 on Fri Dec 14, 2012 10:37 pm

Hi, the only 20 amp inductor I could find cost 200.00 US. I have purchased some small current sensing transformer. The buck converters will always operate in discontinues mode so I think it will work at the AC input and the DC output. I am currently building and new permanent magnet alternator that I can operate using a hand crank then I can start testing some simple circuits and determine the max and min values. I plan to use just one buck converter to interface with the UNO and use software to multiply the values for the hole system. I will post results when available, thanks for taking a interest in the project. I am using a blocking diode at the output of each buck converter.

http://ww2.pulseeng.com/products/datasheets/P578.pdf
Attachments
DSCN2194.JPG
current sense transformer
DSCN2194.JPG (118.96 KiB) Viewed 1934 times
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Re: MPPT for wind turbine

by GoVertical0017 on Sat Dec 15, 2012 7:08 am

http://jarv.org/2009/07/home-power-monitoring/

Hi, I found this project that is very similar to what I am working on. They interface the CT to the Arduino using just a 5 Kohm resistor, can it really be that simple??????
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Re: MPPT for wind turbine

by john444 on Sat Dec 15, 2012 9:47 am

GoV,

GoVertical0017 wrote:They interface the CT to the Arduino using just a 5 Kohm resistor, can it really be that simple??????
Almost. I would include a couple of blue LED's or zeners to put a limit to the voltage the CTs can put out.
With a properly chosen CT and load resistor, it is simple - AC-A in / AC-V out.

Good Luck, John
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Re: MPPT for wind turbine

by lemming86_au on Wed Jan 09, 2013 1:30 am

GoV,

That's a great looking VAWT you are building! Are you documenting your project somewhere that we can take a look at?

Regards,
Josh
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Re: MPPT for wind turbine

by GoVertical0017 on Wed Jan 09, 2013 4:28 pm

http://www.vawts.net/t37175103/started-new-vawt-proto-type/

Hi, the above link is the most complete. I have been working on the project for a number years. Adding the MPPT circuit will offer the greatest benefit. Thank for the interest.
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