Author Topic: dunlite recovery adventures & booster schematic  (Read 1591 times)

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jacquesm

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dunlite recovery adventures & booster schematic
« on: January 03, 2005, 11:30:55 PM »
The dunlite has made it safely back to St. Josephs Island.



The trip took 5 days, my son came along (he's 11) and so did TomW, who we picked up in Iowa on the way to Matt & the Dans.



Going there was the easy part. On Wednesday evening we arrived in Iowa, late Thursday evening we made it to DanB's.



We spent the last day of the year doing all kinds of stuff, talking and walking around, we got a fantastic dinner and DanB and TomW worked on TomW's windmill (henceforth to be known as DanBuilt #20).



The Dunlite was moved from DanB's pickup to mine and strapped down.



The inverter and all kinds of other stuff helped locking it into place so it wouldn't slide around in the bed while driving it back.



After loading everything up we left Saturday morning to make our way back.



All looked well until TomW's wife called us that there was black ice in Iowa, but for the longest time we thought it was going to be ok, the roads (interstates) were in great shape. Then, when we got off the 380 trouble started. We were still about 50 miles away from TomW's house, and we thought we had another hour to go.



Suddenly the truck would no longer respond and we stood on a sheet of absolutely flat black ice, no traction at all...



It took several hours to cross the next 3 miles of road, going so slow that it really wasn't funny. Cars in the ditches, we almost went there ourselves (we had the luminous idea to see if the side of the road would give more traction...). After almost losing it several times we finally made it to the end of that stretch of road and onto a slightly larger road. No more shortcuts :) At one point we had gotten the car to a standstill (I thought) but then we noticed that it was sliding ever so slowly sideways... go figure...



From here to Toms home town it was all pretty good, but when we hit the local roads to get to TomW's house it got worse and worse. One side of the road was a steep rock wall, the other side a steep drop into a river, not the best spot to park your car...



We skidded backwards into someone's driveway and then had to somehow turn around again, easier said than done on this surface.



Another hour and 3 miles later or so we finally made it to the entrance of Toms driveway, 100' up on a 30 degree incline I was about to take a shot at it when I lost control again and we ditched the car right in front of TomW's house.



After unpacking our gear and carrying it up (that was fun... you couldn't even stand there, let alone make it up there carrying a bag or two) I decided to take another shot at it.



Running back and forth with two wheels in the ditch the truck finally made it on to the surface of the skating rink again, and I slowly backed it up until it was positioned in front of the driveway, nose pointing in. I ran it as fast as I dared along the side of the drive, where there was reasonable traction (no studs, no chains!) and made speed as much as I could.



I made it to about 30' from the top, backed the car into the side of the driveway so it wouldn't slide back down, and then shot it across to the grass on the other side of the driveway.



The next day we did it all in reverse, Amy (TomW's wife) helped me to move the truck back down (this took 2.5 hours or so). Little by little using chains, salt, ashes and patience (lots of the latter).



Then my son and I drove back to Canada, where we arrived monday morning 6 AM.



There are no pictures of our travels, sorry about that but we had other things on our mind at the time than cameras... But I'll do my best to document the Dunlite, it's a 2 KW machine, it has some serious damage from an 80' fall (housing is cracked and all the blade shafts are bent, no blades, no tail).



Today I finished working on the schematic for the booster, as promised.



A png file of the schematic is here, and if you have the 'eagle' pcb/schematic capture program then you can download the schematic file.



A brief explanation of how it works:



The three coils are connected to a tri phase rectifier with 'schottky' diodes, the 'lower' diode in the schematic has a fet across it which allows you to short a certain coil to ground. Because all the fets have their gates interconnected when you pulse the gates you short out the coils to ground, and the current will spike. As soon as the pulse (provided by the 555, a 5 KHz pulse with a 3% duty cycle) goes low again the inductance in the coils will cause the voltage to spike to a higher voltage which you can then use to charge your batteries.



The timing is still 'under revision', as is the 'inhibitor' circuit around ic 3A and 3B, which form a 100:1 amplifier and a comparator. If the current (which is sensed across the shunt) goes above a certain preset value (which you can choose with potentiometer R5) the output of the comparator goes low in order to disable the 555 (grounding the 'reset' pin will keep pin 3 'low').



The circuit is fed from a tiny built in power supply that runs of one of the coils in the alternator, to make it 'non parasitic'.



As it stands right now this circuit is not yet ready for 'duplication', but we're working hard on getting the kinks out (quite a few have already been fixed, thanks Don & Tom !)



When it's cleaned up we'll make a pcb for it.



You can check back to the .sch and .png files every now and then, we'll update them as we go to incorporate changes.



Feedback is very welcome, especially from you electronics bufs out there, I haven't really done any for the last 19 years or so, so I'm pretty rusty.

« Last Edit: January 03, 2005, 11:30:55 PM by (unknown) »

Ungrounded Lightning Rod

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booster downside
« Reply #1 on: January 06, 2005, 05:07:10 PM »
A booster circuit like this, using the coils in the genny for the inductors, also boosts the current in the genny, and thus the drag on the shaft.  The average current in the genny, and thus the drag, is the current you pull.  This slows the genny down, possibly below the max power point for the wind.


Of course in a battery charging situation, below cutin there IS no current.  So the drill will be to adjust the boost to cause the genny load to track the max power point until speed is high enough that you no longer want boost, i.e. when the max power point is at the cutin voltage.


You can get a measure of speed from frequency.  I think the dynamics of the system will work out that it will settle on the max power point rather than elsewhere or oscilating if you just adjust current to be appropriate for the instantaneous speed.


Once you're up to where you want to CUT current for max power you can use a second down-converting regulator with an input capacitor and external inductor to trade voltage for current, and let the voltage at the bridge output continue to rise with mill speed.


Configure the second regulator to regulate battery voltage by adjusting charging current (perhaps with constraint finesses: boosting output to prevent overvoltage on the midpoint capacitor and/or unloading the mill, dropping output to avoid overloading the mill and dragging it below peak power point if the batteries are low).  Be sure to use a dump load.  B-)


Such a setup should pay for the extra losses in the second switcher by improving peak power tracking.

« Last Edit: January 06, 2005, 05:07:10 PM by Ungrounded Lightning Rod »

Ungrounded Lightning Rod

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Re: booster downside
« Reply #2 on: January 06, 2005, 05:14:30 PM »
I think the dynamics of the system will work out that it will settle on the max power point rather than elsewhere or oscilating if you just adjust current to be appropriate for the instantaneous speed.


On second thought that may oscilate or settle too slowly on the correct load depending on the damping.  You adjust the damping by adjusting the size of the output filter capacitor and load resistance in the frequency-sensing circuit.

« Last Edit: January 06, 2005, 05:14:30 PM by Ungrounded Lightning Rod »