MPPT for wind turbine

[GoVertical0017]

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?

[GoVertical0017]

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.

[john444]

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

[john444]

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

[GoVertical0017]

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.

[john444]

GoV,

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.

A 20 inductor is to expensive

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

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

[GoVertical0017]

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

[GoVertical0017]

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??????

[john444]

GoV,

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

[lemming86_au]

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

[GoVertical0017]

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.