Author Topic: VAWT new proto-type (Read 250027 times)

GoVertical · « **Reply #462 on:** December 22, 2011, 01:23:09 AM »

Slide cutter for C rotor update:
I still have to fabricate the tube mount. The linier bearings and cutter mount are complete. I should be able to produce some nice cuts. Happy holidays.

GoVertical · « **Reply #463 on:** December 27, 2011, 09:01:23 AM »

http://www.youtube.com/watch?v=SjOW-_sjLYs&feature=youtu.be

http://www.youtube.com/watch?v=SjOW-_sjLYs&feature=youtu.be

Hi, The cutting jig still needs some improvement, the center tube that is being cut moves a small amount in the center and produces a jagged cut. I used a hand plane to smooth off the edges, it is good enough for the prototype. I am adding another stator and mag rotor to the PMA. After that the weight of the PMA will be about 40 pounds. The 6 bladed spokes rotor that I am using does act as a cross flow turbine and adding a C to the leading edge of each blade will also catch the turbulence that is generated at the center of the turbine. The video shows prototype with no load. I am working on 80 inch blades.

GoVertical · « **Reply #464 on:** December 31, 2011, 08:00:58 AM »

Hi, I never understood the need for MPPT. I just watch a video that demonstrates the benefits of adding a MPPT to a wind turbine.

http://www.youtube.com/watch?v=0TE38SOdf64&feature=player_embedded

The video is definitely worth watching if your PMA has high internal resistance.
Comments welcome.

Madscientist267 · « **Reply #465 on:** January 01, 2012, 02:00:45 AM »

MPPT (or even just a modified buck converter) can do wonders when there's a mismatch of significance.

I can't say this with absolute conviction for wind, but for solar, the simplified "pseudo-MPPT" that Commanda helped me build definitely can help squeeze out every drop of juice that would otherwise go to waste...

She has all the details on the full version, really well documented in one of her threads, and my "lite" version of her circuit is around here somewhere too.

If you're interested in building one, that is... I mean, sure, you can buy one, but where's the fun in that?!

Steve

GoVertical · « **Reply #466 on:** January 01, 2012, 05:58:16 AM »

Quote from: Madscientist267 on January 01, 2012, 02:00:45 AM

MPPT (or even just a modified buck converter) can do wonders when there's a mismatch of significance.

I can't say this with absolute conviction for wind, but for solar, the simplified "pseudo-MPPT" that Commanda helped me build definitely can help squeeze out every drop of juice that would otherwise go to waste...

She has all the details on the full version, really well documented in one of her threads, and my "lite" version of her circuit is around here somewhere too.

If you're interested in building one, that is... I mean, sure, you can buy one, but where's the fun in that?!

Steve

Hi, yes I would like to build one. Can anyone recommend a link? I have a small PIC controller that I can use. I found a paper on the subject that uses a sensor to measure shaft RPM and then uses a look up table to control the pulse width modulation to trigger the buck converter. I would like to see if it will improve turbine output at low wind speeds when charging a battery.

Madscientist267 · « **Reply #467 on:** January 01, 2012, 12:51:54 PM »

For wind specifically, I know that the general idea does involve a table of some sort to translate the RPM to a power curve that the MPPT then uses to make it's "move".

The only links to DIY that I personally know about are the two I mentioned above, but they are of the "dumb" variety, meaning that they are pre-set (with solar in mind) rather than dynamically changing around what an alternator puts out.

However, the basis of MPPT is the buck converter, so the same concepts apply to both solar and wind, it's just that the wind version needs a brain to optimize it.

My version, which is just the buck converter without "true" MPPT functionality is here (this goes straight to the pics of the first working prototype).

Her first one (that I modeled mine after) using the same basic design but with additional functionality can be seen just down below mine.

She did a "take 2" synchronous version as well, in an effort to squeeze out even more efficiency. If I were to start over, this is where I would begin, but the asynchronous version (above) worked well enough for my purposes at the time, so I never went into building the second one - http://fieldlines.com/board/index.php/topic,144963.0.html

Seems all that would be left would be to set up your PIC to provide the tracking signals to her enhanced version, and you'd be good to go. Mine strictly monitors the input voltage, and tries to keep it at a certain point, with no regulation imposed on the output (other than "float stop" to prevent the output from soaring too high under no load).

She can tell you much more about them than I can; I understand how they work, but the synchronous version is completely her brainchild and she understands it inside and out.

Although, I haven't seen her around lately...

Hope this is of some use...

Steve

GoVertical · « **Reply #468 on:** January 02, 2012, 10:18:33 PM »

http://www.youtube.com/watch?v=0TE38SOdf64&feature=player_embedded

Hi, yes it is very helpful, thank you.

I found a article in Power Electronics Technology_ June 2006 â€œBuck-Converter Design Demystifiedâ€

http://my.ece.ucsb.edu/Bobsclass/194/References/NonIsolated/Buck/Buck%20Converter%20Design%20Demystified%20606PET25.pdf

The article provides methods for selecting component values for a basic step down converter circuit and I plan on using it as a guide to develop the MPPT. I will post updates when available. Thanks again.

GoVertical · « **Reply #469 on:** January 10, 2012, 06:26:38 AM »

I started a project for a very basic buck converter to determine if it will produce a higher output from my PMA at a lower wind speed.

As I understand the circuit chargers the output inductor when the MOSFET is on.
When the MOSFET is off, the turbine will be allowed to maintain a higher RPM and the energy stored in the inductor will discharge current into the battery.

The output voltage will always be fixed to the battery voltage.
The input voltage will change as the turbine RPM changes.
The input voltage will be high with low current and the output voltage will be low with higher current because the energy stored in the large output inductor will discharge into the battery as the MOSFET turns on and off.

I have all the parts to fabricate a very basic low amp output buck converter.
I am trying to design the basic test circuit so a micro controller can be added if required.
This is a first attempt at designing a power circuit.

I am making progress. I purchased more binding posts so I can more easily change the cap and inductor with different values. I am working on the gate oscillator. The biggest challenge is finding away to connect the boards that will able to carry the increased current. The first test circuit will have a five amp maximum limit mainly because the only diodes I could find have a 3 amp rating. I am running two in parallel. Comments welcome

GoVertical · « **Reply #470 on:** January 11, 2012, 09:44:47 AM »

Hi, project update.
Waiting for ordered parts.
I found a link that show Hall effect sensor to measure current if micro control is required.

http://scienceshareware.com/how-to-measure-AC-DC-current-with-a-hall-effect-clamp-.htm

I do not know if the switching frequency has to be adjustable for the circuit to function at different wind speeds.
comment welcome

GoVertical · « **Reply #471 on:** January 16, 2012, 09:53:45 AM »

Hi, I received a recommendation to add a voltage comparator to turn off the switching frequency when Vin is lower than Vout. This will prevent a reverse current through the MOSFET. I tried a very basic experiment by hooking a 7200 MFD 50 VDC to the bridge rectifier and used the PMA to charge the capacitor. I was surprised how fast and how little effort was required to charge the capacitor to 50 VDC. Waiting for new oscilloscope to arrive and will post test results when available.

GoVertical · « **Reply #472 on:** January 21, 2012, 05:38:24 PM »

Hi, I spent the last few days trying to get the nand gate oscillator to oscillate and show the output wave form on the O-scope. Step one complete, next is the voltage multiplier. I will post updates when available.

GoVertical · « **Reply #473 on:** February 18, 2012, 06:11:34 AM »

http://www.usna.edu/EE/ee320/Supplements/dcdc5_driver.pdf

http://web.mit.edu/6.131/www/datasheets/float_drive.pdf

Project update:
I was band forever from the forum.
I was reinstated to the forum.
The new used scope fried and lost trace.
Purchased another new used scope.
Purchased IR2117 gate driver chips.
Using the app notes I derived buck converter circuit.
Completed high current connections for proto board.

I finally had time to test the circuit with a oscilloscope and found the oscillator is working but the gate driver is not firing and the MOSFET is passing current that is shown in the video with out being turned on. I found one problem. The nand oscillator is only putting out a 5 volt timing signal. The IR2117 has a input low voltage lockout. I have to increase the voltage of the timing signal.
I guess not all 4000 series are the same, thing do change.
From the application notes it looks like the IR2125 is designed for a 12 volt battery charging circuit. The IR2117 is designed for resistive loads. I am proceeding with what I have. I will be happy if I can just get a MOSFET to trigger at this time and I will post results when available.

http://www.youtube.com/watch?v=GtSDK2HSnGA&feature=youtu.be
Not a valid youtube URL
My concerns are there is a lot energy stored in the input capacitor and I do not want to harm my oscilloscope. Are there any points I should avoid when testing the circuit?

? The chassis ground and each channel ground are a the same common point, is there a safe method to use when testing the circuit with the scope? Comments welcome.

GoVertical · « **Reply #474 on:** March 10, 2012, 07:29:34 AM »

Greetings, I added the larger caps to the boot strap and the ringing is still there but only noticeable at lower RPM's.

I am still using the 555 timer. I increased the duty cycle to 80% and inverted the output so the duty cycle at the input of the IR2117 is 20% high. I connect a 12 volt 50 watt light and spinning the PMA manually I was able to illuminate the 50 watt light with relative ease. Wow, a shorter duty cycle made all the different. The PMA was much easier to spin and even maintained momentum for a short period when I stopped spinning the PMA.

Without the buck converter I was unable to illuminate the 50 watt load under manual operation.

I am still using the bench power supply to power the IC's.

Performance has definitely improved.

I still need away to control the duty cycle at different PMA RPM's and find away to power the IC's from the battery or PMA. Next step is to try charging the battery. It maybe time to start thinking about adding a micro controller. Thank you for all the suggestions.

video:

http://www.youtube.com/watch?v=B3dLzZZ5jKQ&feature=youtu.be

GoVertical · « **Reply #475 on:** April 18, 2012, 09:07:05 PM »

Hi, added new analog test circuit. I am now using a FOD3180 gate driver with isolated power supply.

Testing a analog circuit will help me better understand the MPPT requirements and verifying the circuits operation will reduce errors when microcontroller is added.

Circuit update: currently constructing new test circuit. Added fixed frequency timer and one shot 555 to provide stability for duty cycle adjustment. Updated test points and added Vin discharge push button, also included on/off circuit power switch. Commen welcome.

I need a regulated 12 volts for the IC’s Vcc and to supply the isolated power supply for the FOD3180 gate driver. I am searching for a circuit that would work using Vin, but the input voltage can change from a very high voltage to zero volts depending on the RPM.

*** found other project that is similar *****
http://www.zilog.com/docs/z8encorexp/appnotes/an0223.pdf

OperaHouse · « **Reply #476 on:** April 22, 2012, 06:26:33 PM »

I see a UNO board. In a couple of weeks I will be posting my project, Two independent power point solar regulators with hot water tank dump load and a freezer based fridge operated as a dump load all using s single UNO board.

GoVertical · « **Reply #477 on:** April 22, 2012, 06:39:59 PM »

Hi, Wow, sounds great. I look forward to your post. What are using to interface the input and output sensors, drivers, to the Uno? I am just working on a analog test MPPT board so I measure the input and output values before I try to interface with the Uno.

GoVertical · « **Reply #478 on:** April 30, 2012, 10:52:37 PM »

Hi, I completed fabrication of analog MPPT test circuit. Video shows verification of selectable duty cycle with fine adjustment of each for each selected duty cycle, 10% to 50%. Next step is to test with PMA and battery test load. I am hoping I did not damage the mosfets when I solder them in the circuit.

GoVertical · « **Reply #479 on:** May 14, 2012, 01:02:16 AM »

http://www.youtube.com/watch?v=RqBQzoq_ctc&feature=youtu.be

New test data;

rotor speed 500 RPM
Vin 40voltsDC
Iin 3amps
Vout 12voltsDC
Iout 6amps
Duty cycle 50%

Stators 4 coils per phase
stator resistance < 1 ohm

Circuit temp 82 degrees Fahrenheit

Inductor temp 170 degrees Fahrenheit
I need a better inductor.

Replaced inductor with larger air core. Results improved. Inductor temp much cooler. About 60 watts at input and about 60 watts at output. Using analog current meters. I was damaging DMVs trying to measure higher current for longer periods of time.

GoVertical · « **Reply #480 on:** May 15, 2012, 08:58:41 AM »

Hi, I configured the PMA using just 2 stators to form a 3 phase star, 8 coils per phase. Phase to phase resistance = 9 ohms.

Rotor RPM_____Voc DC
100____________15
200____________30
300____________45
400____________60
500____________75

Rotor RPM_____Vin DC____Amps in____Amps out
100____________16.5______? _________0.2
200____________27.3______0.2________1.0
300____________28.8_____ 2.0_________5.0___Vout = 12.8Vdc

Free diode temp = 82 degrees F
50% duty cycle
test fixture limit 300 RPM using load

Vout = 12 volt deep cell test load
measurements ball park , 60 Watts appears to be the limit of test fixture under load.

I have to remove one stator and rotor and then I will be able to road test. Search for ideas on how to limit voltage to 100 volts at the input to protect circuit. Comments welcome

I am do not know how to measure current with a O-scope. I am researching the method.

Maximum current output without using the circuit 2 amps. The circuit is definitely is a benefit.

DamonHD · « **Reply #481 on:** May 16, 2012, 02:41:18 AM »

Very good!

Rgds

Damon

GoVertical · « **Reply #482 on:** May 16, 2012, 06:41:29 AM »

Hi, thanks, I see one problem. I have more power at the output than at the input. I should be the other way around. I have changed the meters and I still get the same results. It is very puzzling, but the circuit is working. I to have rebuild the PMA than I will be ready for a road test.

I plan to add a fuse at the input to protect the circuit from over voltage. I am still searching for a better solution.

GoVertical · « **Reply #483 on:** May 18, 2012, 08:23:56 AM »

Hi, completed stator and rotor removal. Weight is less, spins easier.
I hope to road test soon with buck converter.

Tritium · « **Reply #484 on:** May 19, 2012, 05:00:25 PM »

I have watched this project for nearly 2 years now. 483 post and 56651 views. You have reached 2A output without MPPT and 5A with in your most recent posting of figures. Most others would have run off screaming mad into the darkness by now. I applaud your tenacity sir

. When you start a project you certainly do see it through.

Thurmond

GoVertical · « **Reply #485 on:** May 23, 2012, 10:00:21 PM »

Hi, I always avoided the F&P because the output was so high. I did not know how to control the output. I learned a lot when I did the buck converter project. I am increasing the input voltage limit of the circuit to 450 volts DC. The new parts for the circuit just arrived and it will me a few days to build the new circuit then I can test the F&P using a drill press.
I will post results when a available.

GoVertical · « **Reply #486 on:** May 24, 2012, 10:21:19 PM »

Hi, I needed away to secure the mag rotor to rotating center shaft. I did not want to weaken the mag rotor by drilling holes in it. My solution was to add coggs to the Blade rotor plate and the coggs will push the mag rotor.

GoVertical · « **Reply #487 on:** May 25, 2012, 09:00:51 AM »

Hi, F&P open voltage measurements.
12 coils per phase, 3 phase star, phase to phase resistance 37 ohms, load 450 volt 470uF capacitor.

RPM________Voc DC
100_________130
150_________180
200_________230
250_________280
300_________330
just ballpark measurements, when circuit is operating the input volts equals half of the open circuit voltage.

GoVertical · « **Reply #488 on:** May 26, 2012, 05:05:26 PM »

Improved mag rotor coggs

GoVertical · « **Reply #489 on:** May 30, 2012, 11:04:47 AM »

Hi, ceil fan stator mount completed. The stator has two separate windings, a outer and a inner. Both are 16 coils in series. I do not the phase relationship. Outer coils internal resistance measurement is 158 ohms and the inner coils measure 140 ohms. I am now fabricating on the magnet rotor. I have no idea what to expect for a output but I will be able to test two different axial flux PMA's with the buck circuit.

GoVertical · « **Reply #490 on:** June 09, 2012, 11:10:55 PM »

Hi, results from today's stock F&P and Buck converter tests:
I replace the failed diode with five 3 amp 400 volts diodes and connected them in parallel. After increasing the PMA RPM above 100 the timing signal became unstable and the mosfet and diode array became very hot. Highest temp reading was about 140 degrees Fahrenheit. Then the mosfet or diode array stopped working. I will have to investigate to determine which one or both failed. Before the failure I was able to observe at shorter duty cycles the buck converter stopped converting and was feeding large voltage values into the battery, sometime above 100 volts.

Conclusions from today's test:
1. The stock wiring of the F&P produces a voltage much to high to be used with a buck converter to convert down to 12 volts for battery charging. The stator should be re-wired so that multiple phase coils are connected in parallel to reduce max voltage output to 50 volts for the max RPM of a turbine. Because of the quality of the materials; the plastic holding the stator together and the time involved to re-wire the stators I believe it is much easier for me to fabricate the PMA using established fabrication techniques.

2. After reviewing component cost and availability I am pursuing 5 amp power module configuration with single timing controller board, so for a 15 amp output would require one controller board and three power modules. I am not sure if it will work.

What I need to find out is as more power modules are connected in parallel can the switching frequency remain constant, or does the switching frequency have to increase because each power module will have its own inductor and connecting the modules in parallel will reduce the inductance and cause the inductors to saturate. I am not sure and comments are welcome.

GoVertical · « **Reply #491 on:** June 22, 2012, 08:45:04 AM »

Hi, making progress. I only have enough parts to fabricate three Buck power modules. It is enough to test with. I still have to route wire connections and fabricate controller board.

seilertechco · « **Reply #492 on:** June 24, 2012, 12:12:17 PM »

Vertical, this is a late question I know, but have you considered combined permanent magnets and electromagnets for a variable magnet strength?

I'm late to your party but also admire your tenacity. As a "newbie", I haven't been beaten down enough to know to keep my mouth (fingers) shut up (yet).

Toby
seilertechco

GoVertical · « **Reply #493 on:** June 24, 2012, 12:23:21 PM »

Hi, what would be the benefit?

seilertechco · « **Reply #494 on:** June 24, 2012, 12:40:19 PM »

A permanent magnet is always at one level of strength. If I place a winding around the PM, I can put a dc current into it that does one of two things...it cancels out the PM or it increases the strength, depending on the flow of the dc in the exciter, either positive or negative. Strength of this "exciter" is also a factor.

I can cancel out the PM (partly or fully) or I can add to it. Low winds demand low strength magnets, high winds demand more strength. This assumes one wants to have widely variable output, low cut in at low speed and very high output at high wind speed. I think of it as a "transmission" for magnet force, low in low wind and high in high wind.

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Author Topic: VAWT new proto-type (Read 250027 times)