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Hi,
I have to create a simulink model of a wind turbine and wind. I have read dozens of papers about wind turbines physics, but still I have several problems..
The only data about the windmill I have got is the power curve (wind speed - power curve), diameter and thats basicaly it.
I wanted to start with modeling the dynamics of the turbine without asynchronous generator, but I have no idea how to calculate J (total moment interia). Could anyone please help me with that? I hope I will soon get the weight of the blades (there are 3 of them).
Next problem is how to determine Cp (power coef.) and TSR (tip speed ratio) from the power curve - there is no way how to measure them and the manufacturer does not reply to my mails and calls. I even dont know how fast the rotor rotates (in dependace on windspeed)...
T(W,v)=1/2 * ρ * A * R * (Cp / λ) * v^2
//ρ - air density, A-swept area, R-radius, λ-TSR
P=T(W,v)*W
//P-power
Hopefully with your experiences my problems could be solved..
Thank you!
Pavel
PS: its a "DIY" 5kW windmill therefore no info online
Bolty Regular Member Joined: 03/04/2008 Location: AustraliaPosts: 81
Posted: 01:38pm 03 Apr 2008
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I guess the date of posting and the "no replies" implies that people think that this is an "April fools day trick"
MyCattMaxx Newbie Joined: 24/02/2008 Location: United StatesPosts: 8
Posted: 02:40am 04 Apr 2008
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I thought since it is a first post it is someone looking for others to do their homework for them.
KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691
Posted: 09:02am 07 Apr 2008
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Dobrý večer Pavel
I am sorry but your theoretical approach to this subject is far in advance of my simple knowledge.
My experience is at a very basic practical level in which I start with a piece of junk (for example an old washing machine motor) and experiment until I get some useful result. I envy you if you are able to do these same 'experiments' on paper!
Na shledanou
Honza de Novu Zealandu
GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127
Posted: 11:47am 07 Apr 2008
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The inertia will be determined by the moment of inertia and the angular velocity. The moment of inertia is determined by the total rotating mass and spatial distribution of that mass. You seem to be missing much of that information. Most physics texts have chapters related to rotational properties of mass.
I do not think it is possible to determine the TSR from a power curve directly.
Most manufacturers would be unwilling to part with the technical info you are requesting.
Part of the problem w/ interia is already solved - I estimated the weight of the blades and calculated J - but the result could be very far from the truth.... (whole wind mill with generator weights about 70kg, the blade could have around 2-3kg is it right)
Well, you think that having only power curve there is no way how to create a model from the first priciples?
Through internet I havent found any Cp - TSR curve for such small windmill (i made a mistake above, it is only 1.5kW), that was the main reason I made a post here - I have no idea how the curve could look like and I believe that many people here have this information (having similar windmill at home etc.). I am not in windmills very much, I am doing this model (and all the physics stuff)only for creation of control system and reagulation of energy consuption in a house...
I was quite dissapointed by the first two post, becouse it is really not the way they say - it is not a "homework"...
petanque don Senior Member Joined: 02/08/2006 Location: AustraliaPosts: 212
Posted: 01:38am 08 Apr 2008
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I must admit I looked at the post and wondered why not start with existing 5Kw windmills and copy them?
I struggled to understand why you needed to make a mathematical model on all these seemingly theoretical concepts.
Why reinvent the wheel when there are plenty of wheels to copy? Or at least be a starting point.
GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127
Posted: 01:40am 08 Apr 2008
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Maybe this is the the question you should have asked?
I am not really into the theory too much. I have previously posted graphical output data from my windmill. My mill has a linear TSR and a cubic power output with increasing windspeed up to furling windspeed, but this will not be the case in your situation.
I cannot see how a windmill design has much bearing on a control system for regulating energy consumption in a house. Storing all the collected energy and regulating usage might work.
I did not write it correctly - windmills (there is 8 of them), diesel generators and solar panels are used to generate power in a project I am working on. Models of these power generating capacities have to be done to extimate optimal usage of them (using data of consumpion of energy). There is going to be a model of the wind from data obtained from the site, therefore (using the model of the windmill) energy generated from the windmills can be estimated. I did not want to go into these details... I spoke with the manufacturer of these 1,5kW windmills and he would not give me any other information (all I have is the power curve). Therefore I have to get as similar data as possible - I think (thats only my "newbie" idea) most of 1,5kW windmills will have very similar properties. I hope, that someone has similar windmill at this server.. if not here, then I have no idea where to find it...
thanks for the previous reactions..
petanque don Senior Member Joined: 02/08/2006 Location: AustraliaPosts: 212
Posted: 01:10am 10 Apr 2008
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Wind resources can be extremely variable.
Depending on season and location.
Unless you have very high towers or very smooth terrain sites within even 50m can have markedly different outputs.
GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127
Posted: 02:32am 10 Apr 2008
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Hi Pantau,
I think you may need a crystal ball.
I have used experimental data over a whole year and I am still unable to model how much power I can expect on a daily basis. You sound like you require real time modeling.
I don't think many forum members can help you. Gordon.become more energy aware
Hi don Petanque and GWatPE,
I am not having problem with wind modeling right now, my plan is to create a model of wind using 3 methods: von Karman & Van der Hoven, Shinozuka method and method using day/night means and corelation - and compare them.
Right now I am having problem with the windmill - I have the model but I am missing the Cp-TSR curve which is needed for correct response...
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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