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Forum Index : Windmills : F & P Voltage and Current control

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BjBlaster
Regular Member

Joined: 04/04/2008
Location: Australia
Posts: 55

Posted: 02:50pm 13 Apr 2008

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Hi Guys,

I've been playing with a few ideas and have come up with a relatively cheap method of regulation over a wide range of RPMs using a switchmode power supply. I was wondering if anyone has tried this before because it looks promising. I was thinking more of larger supply (modified PC PSU) for a slightly higher voltage (13.5V) for charging but it sure does solve my voltage boosting issues.

Have a look at my test of running the F&P factory stator in 3 phase to a rectifier and a multi voltage PSU. The video shows it running over variable speeds dishing out 3A @ 12V constant.

F & P Switchmode Idea

Cheers

Bj

Check out my projects here in:
Bj's Shed

GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 01:28am 14 Apr 2008

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Hi BJ,

The high voltage operation you are working on will be of use to some readers.

The power supply you used is rated at 4A. You have loaded the test to 3A. The output will be constant with increasing RPM in this situation. You will probably find, if you did measure the input power that this would not have changed much either. What you will find if you were able to look at the duty cycle of the SMPS is that it would have reduced as the speed was increased, to maintain the constant output power. Unfortunately the energy in the wind does not follow this relationship. The windmill has to be loaded more as the wind power increases. The rpm should increase linearly with the increasing windspeed to maintain the blade optimum TSR, the power increases with a cubic relationship.

I am still working on a boost/buck design. Once my F&P mill is finished I will continue my testing. This aspect of windmill control is pretty difficult and will probably be a compromise somewhere. I am working to a maximising system up to the battery voltage and then a constant mill current to preserve the windings. The very top end will be controlled by the furling mechanism. I will be experimenting in the 500W maximum power area.

Good luck with your future testing... Gordon.

become more energy aware

BjBlaster
Regular Member

Joined: 04/04/2008
Location: Australia
Posts: 55

Posted: 02:20am 14 Apr 2008

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GWatPE said Unfortunately the energy in the wind does not follow this relationship. The windmill has to be loaded more as the wind power increases.

Thanks for the info Gordon,

That was my next experiment - but what maximum power is the F&P rated for for continuous use? I'll be using some sort of vertical mill (not sure what type at this stage) but it will be low rpm. 500W max would be good to aim for in a modified PSU design so I'll aim for constant voltage (13.5V) and variable current up to a max of 35A (around 500W). Not that I except to get 500W out of a vertical mill, but I think its worth investigating this as an alternative to a low voltage buck/boost design.

I may have to rethink the loading option - maybe get some feedback from the AC feed to calculate the SMPS duty cycle ...
hmmm now you've got me thinking :)

Check out my projects here in:
Bj's Shed

GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 12:56pm 15 Apr 2008

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Hi Bj,

Forum members with windmills are looking for a universal high voltage solution MPPT. I was to post a detailed reply for you re SMPS but after the MPPT disaster, I will wait until my testing is complete. I hope the regulated output SMPS gives you good results.

A std F&P has a useful output proportional to RPM. This can range from 200W to above 700W. A direct drive VAWT may require a rotor makeover with more powerful magnets to provide useful output at lower RPM, if a gearbox was not used... Gordon.

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sPuDd

Senior Member

Joined: 10/07/2007
Location: Australia
Posts: 251

Posted: 12:25pm 16 Apr 2008

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G'day BjBlaster,

I have to say this first up. I've been reading through your web site for many many hours and - DUDE YOU ROCK

You're more project crazy than me, and I don't have responsibilities

You're a prime example of the inventiveness of an Aussie

Dude, seriously - you'd make a great movie :)

Love ya work - Humble sPuDd..

It should work ...in theory

BjBlaster
Regular Member

Joined: 04/04/2008
Location: Australia
Posts: 55

Posted: 07:28am 17 Apr 2008

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Thanks for the kind words Spudd, It's always good to see people enjoying the site - and that it part of the fun! I try to keep most of my projects up to date so others who are attempting the same can learn from my tests/experience and hopefully same them some time/money along the way ;)

Cheers

Bj

Check out my projects here in:
Bj's Shed

martinjsto

Senior Member

Joined: 09/10/2007
Location: Australia
Posts: 149

Posted: 01:48pm 21 Apr 2008

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great thinking bj shows promise and got me looking at my junk pile more closely, keen to see more results as they come in
keep up the good work
martin

free power for all
McAlinden WA

BjBlaster
Regular Member

Joined: 04/04/2008
Location: Australia
Posts: 55

Posted: 07:37am 22 Apr 2008

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I've got to make a more suitable test rig - or actually get around to building my turbine to make testing easier. I will keep you posted with updates as soon as I get a chance to arc up (nice pun) the welder and build a frame for my mill.

Check out my projects here in:
Bj's Shed

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