Author Topic: Getting there  (Read 815 times)

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bigkahoonaa

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Getting there
« on: September 12, 2007, 03:25:00 PM »
I finally got everything connected.. But then I had problems with my RPM sensor, and then one of my relay boards would not release breaks.  After fiddling around for several hours, everything is now working!  Of course now there is no wind, or very little.


I ran a test on the weekend in a wind speed of about 2 to 3 m/s.  I needed to give the wind mill a little push to get it started, but once it was going it would drive at about 30 RPM.  I checked the voltage on the AC side and I noticed something peculiar.  The AC voltage was pulsing.  It would go from 4 to 8 to 12 to 14 VAC, and then it would drop suddenly back to about 4 VAC.  The AC side would pulse like this every second or two.


It reminded me of something that Flux said in my first post, about pulse width modulation and MOSFET.  Since the AC voltage is pulsing anyway, I'm thinking of adding a PWM on the DC side and vary duty so that voltage of one pulse on the DC side can exceed battery voltage.  

« Last Edit: September 12, 2007, 03:25:00 PM by (unknown) »

JW

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Re: Getting there
« Reply #1 on: September 15, 2007, 09:07:21 PM »
Hi bigkahoonaa,(BIG- Kahoooouna)


 (JW)I wanted to comment before your diary entry, slipped of off the front page.


"What do you want to do with the power? Direct lighting will not be very satisfactory.


Any form of load that doesn't include a battery will need a controller to keep a decent and safe output as you have already found.


Flux"


(JW)Ya, I see what is being said here. Often I see Flux repeating himself, so dont worry that you havnt more feed back...


"-I ran a test on the weekend in a wind speed of about 2 to 3 m/s.  I needed to give the wind mill a little push to get it started, but once it was going it would drive at about 30 RPM.  I checked the voltage on the AC side and I noticed something peculiar.  The AC voltage was pulsing.  It would go from 4 to 8 to 12 to 14 VAC, and then it would drop suddenly back to about 4 VAC.  The AC side would pulse like this every second or two.


bigkahoonaa-"


(JW)OK, ok this is to be expected.


"-It reminded me of something that Flux said in my first post, about pulse width modulation and MOSFET.  Since the AC voltage is pulsing anyway, I'm thinking of adding a PWM on the DC side and vary duty so that voltage of one pulse on the DC side can exceed battery voltage.


bigkahoonaa-"


(JW)HAVE YOU EVER CONSIDERED what a capacitor would do to the output waveform connected in parallel? Its been said many times a discharged(or charged battery for that matter) battery will smooth waveform occilations. Not only does this enhance the 'reserve' output capacity of the circuit, the outputs tend to be more 'heavy' if you will. Direct output of the full rated capacity in watts, will always be demished by a so called 'lightwieght' circuit so to speak. PWM is great if max output in amps is instantanious. But this is often not the case, in direct wind generator(output) applications. You most often will need a battery to run that invertor at full output. Diversion loads are very useful to permit limiting of speed on a given wind turbine, but in general, diversion loads(alone) are not suitable to run a 3000w invertor.


But you could try for that, I guess. But most likely, now matter how advanced the waveform is, that you generate, it will(most likely) miss-match the invertor since it needs flat-line DC input.


JW

« Last Edit: September 15, 2007, 09:07:21 PM by JW »