Homebrewed Electricity > Wind
Help needed on a Breezy type grid tied induction turbine
Kyle:
Thanks for your input. It will take some time for me to sort through it. Tons of great information. I do plan on a controller. Jondecker76 posted http://www.fieldlines.com/index.php/topic,138266.msg917173/topicseen.html#msg917173
Where he made a controller that does that. I am hoping he was successful and has a product available.
I am also worried about creating one huge fan. I hope to spin it up and when it is close to sync speed, (ala hall sensor) cycle off the power and let the wind bring the rpm above sync before powering back on to generate. Use an anemometer and relay to only turn it on when wind speeds are of value.
I was wondering what kind of output I could get. Is the 300 watts due to the conversion of 3 phase to single with the capacitors?
george65:
So seems I was correct, one DOES need a controller for a setup like this.
The people you first mentioned must have used one.
The 300W output is more due to the fact you are using a motor as a generator instead of a motor.
I have read claims of 75% generation but that tends to be on white papers and real world accounts tend to tie in with my own at closer to 50% or a fraction less.
There are a number of factors in using a motor as a generator that account for the reduced output but it's a while since I read up on it and I won't go into details because I'll surely use the wrong term and get lambasted for it. :0)
Guess all you need to know is it is inefficient because you are using something in a way it was not designed for and that's the price you pay for a cheap generator.
Wouldn't be anything to stop you using a 2KW motor and getting 1000 watt or maybe 1100 the same way as long as your blades are big enough to drive it in the prevailing wind.
SparWeb:
Sounds challenging, certainly a learning opportunity.
The controller Johndecker worked on sounds like the thing you need. I don't remember an update following that project. It will take a bit of know-how with motors to make the hook-up work. As George puts it, "you are using something in a way it was not designed for".
Bear in mind you will also need the encoders, the resistance load, and then... <ahem> some way to convince your electric utility that you know what you're doing and that the output power will be suitable for whatever feed-in plan they sign you up for. This is the biggest hurdle you face. Given that the electric utility is a powerful "gatekeeper" on a grid-tie installation, making them angry leads to all sorts of unpleasantness. Be careful and make sure you know you will be accepted before even asking them the question. Be prepared to play by their rules. Accept that they are paid to keep everyone safe and running efficiently, and everything below a megawatt is "small fish".
george65:
--- Quote from: SparWeb on December 22, 2017, 11:39:03 PM ---
Bear in mind you will also need the encoders, the resistance load, and then... <ahem> some way to convince your electric utility that you know what you're doing and that the output power will be suitable for whatever feed-in plan they sign you up for.
--- End quote ---
This is a significant point IF you are worried about having everything approved etc.
To me, the current pricing of solar makes wind a rather expensive proposition if there is any alternatives. For some there isn't a lot other alternatives and cost is not the issue as much as have or have not. Where solar is available, it is far cheaper, more developed and easier to get approval for.
For experimentation purposes and learning if that's your base goal, maybe look at building the same sort of thing only replace the blades with a small Diesel engine and run it on veg oil. Everything else will be the same so you can still learn most of it.
With Solar panels, no one pays any attention to them. Unless you are on land, just the erection of a wind tower will also put the wind up your neighbours as well as the local authorities. The tower itself incurs significant cost and it's a bit hard to hide the things if you are trying to fly under the Radar. I would imagine most places less than decent acreage would have strict rules about the construction of such towers and the approval process would be a cost and drama in itself.
joestue:
i think you have a good chance of doing this if you wire your motor for 138 volts delta, and if you run a 150 volt battery bank/load. this might be as low as practically possible.
Take a vfd and find where it senses the line voltage. then replace the igbts with mosfets. run the vfd from a small 120vac or 120/240v isolation transformer if 150vdc is too low a voltage to get it to turn on. this is only to supply the vfd with power through the existing flyback transformer.
run the mosfets directly to your 150 ish voltage battery bank/load. you may be able to get by with 100, AAA nimh batteries.
so now you need to program the vfd for a non linear volts per hz curve. you can then further manipulate the actual volts/hz output by manipulating what the vfd thinks the line voltage is. you may be able to get an additional 2:1 ratio over what the vfd can be programmed for.
then you need an arduino or some other means of telling the vfd what frequency to output to the motor. there is both an optimal volts and an optimal hz for both the rpm and the torque going into the motor. this could be analog, lots of vfds will accept a 0-10v input.
due to the cubic nature of the wind power, and the torque on the generator follows windspeed squared.. the volts per hz will need to be proportional to the wind speed assuming the slip frequency is set to a constant value.. it doesn't have to be.
you can then send the 150vdc into a grid tie inverter
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