Breakthrough In Small Wind Technology

Nov 19

Breakthrough In Small Wind Technology

Posted in Energy Inventions | Wind Power | Wind Turbines

The main work of wind turbines is to utilize the energy of wind and convert it into electricity; stronger wind is considered good for electricity production. But the speed of wind should not be too strong because it makes turbines spin too fast and in this process it commits suicide! Why is it so? Because turbine blades get ripped off by stronger winds – excessive heat damages the alternator. Turbine tower too can’t remain unaffected by the strong wind. To prevent all this damage a mechanical breaking system furling is generally used. This method prevents wind turbine from spinning too quickly by turning the blades away from the direction of the wind. Furling can be manual or automatic with same goal i.e. turning the turbine blade edges into the wind when the wind is dangerously strong and stormy.

Furling acts by decreasing the angle of attack, which lessens the induced drag from the lift of the rotor, as well as the cross-section. One major problem in designing wind turbines is getting the blades to stall or furl quickly enough when hit by a gust of wind. A fully furled turbine blade, when stopped, has the edge of the blade facing into the wind. But True North Power NG has launched a small wind turbine without a mechanical furling system at their test site in Ayr, Ontario, Canada. Instead of furling system they are using a microprocessor which will manage the speed and power of the wind turbine rotor in all winds. This system was introduced this month and named as True North Power’s 1kW WIND ARROW. AFCTM’s USP is that it lets the WIND ARROW turbine to generate power under control in high speed winds when usual wind turbines have to be stopped or being forced in and out of wind mechanically.

Senior US and Canadian researchers termed this system as “first intelligent controller” because it works without mechanical furling system. They find this system more reliable than usual turbine controllers. The biggest advantage of this system is that it produces more energy annually than typical mechanical braking systems of the same size. This “intelligent controller” with no furling parts and fewer parts overall, is less prone to wear and tear and minimizes its opportunity for failure.

The AFCTM manipulates the WIND ARROW turbine and slows the speed when it approaches the power limit at around 30mph (~50km/hr) and 1200 watts. The AFCTM pulls strings or here, blades of turbines at optimal speed, until the wind gusts subside. The AFCTM releases the turbine once the wind gusts subside, so that it quickly regains its equilibrium in terms of speed and power. This AFCTM achieves all this tasks incessantly without putting additional burden on the system. If a wind speeds above 40 or even 50mph (~80km/hr) is experienced for a prolonged period, the turbine is controlled against over speeding while continuing to produce as much as 30% or more of its stated power. The controller has excellent mechanism when a storm approaches. It switches on its SOS mode or prefers Storm-Otto-Shutdown. The SOS mode is equipped with an electromagnetic braking system. The breaks remain operational till the storm subsides or waits for an operator to restart the system (controller RESET).

Intelligent controllers like the AFCTM are the need of the hour and they have an advantage over eco-friendly energy solutions.

Visit True North Power

Daniel Baldacchino

As far as I am concerned, the issues with operating at higher than normal wind speeds are the rotational speed of the blades (they must be have a somewhat constant angular velocity to produce the right frequency electricity) and that the forces acting on the structure become excessive if the blades were to keep turning this they offer more resistance, and so the machine has to be shut off. Perhaps this is more the case with large machines. I cannot at this point in time see how this microcontroller can be implemented on large machines since you still have the issue of overloading of the structure…
Dylan Manthei

Although I am still in school for mechanical engineering and my knowledge is limited, this seems like a bit of a waste. I have heard of these before and understand the purpose, but can’t we develop technology that uses this excess of energy rather than burn it off as heat? Why not put a second-stage portion in the alternator that offers very high resistance but generates a lot of power…it could be engaged via clutch, relays, etc. Then this heavy load would slow the blades down, while also generating electricity temporarily as the blades slow down. Maybe even a CV type design could prevent constant on/off as the blades slow down then speed back up on a very windy day. The CV could engage the “second alternator” at an infinite number of gear ratios to increase or decrease the load based on how fast the blades are spinning.

I am a learning someday-engineer…please tare apart this idea so I can learn more 🙂
Rob

You’re idea is a good one and I agree that it seems like such a waste to burn off the excess energy as heat. However, I don’t think your idea addresses the idea of protecting the equipment from wind damage. The pivoting fan addresses both issues – 1) protecting the blades from excess wind speed and maintaining a more constant speed to produce efficient energy.
Reynaldo Bacucang

I am not an engineer but a concerned citizen that really cares about what’s happening to our environment. Comments by Rob, Dylan and Daniel should not be set aside but given at least a second look by people/engineers connected to the improvement of wind turbines in harnessing the full potential of wind power.
Cyril R.

The heat overload problem in the alternator could also be somwhat mitigated by more effective cooling systems.

The carbon foam radiators are very effective and lightweight, so could be of good use here.
Gary

Dylan’s idea popped into my head as I began to read the article. What also entered my mind was the additional torque placed on the blades and the tower. I think the tower could be built to handle it, but blades I’m not so sure due to excess weight. If the blades are built stronger and probably heavier then wouldn’t they become less effective in lighter winds?
Loic

Hi,
I had really like to know how is working this control system. Does it interact with the angle of the blades? Does it interact on the alternator level to play with the magnetic brake?

To respond to Dylan : This is technically possible to implement “second-stage portion in the alternator” to be able to use the turbine at high speed but… it leads to much more problems like overheating, resistance of the blades, of the tower… and solve all this costs a lot of money in comparison to the poor amount of energy you could get because the period of high wind are infrequent.

In fact I you were in a region were the wind is frequently at 60km/h, you just built an adapted turbine.

In reality the lack of wind is much more a problem.

Loic, working on turbine for blueEnergy
Stephen

I recall seeing a wind turbine in the Karoo in South Africa which pumped water, with an additional blade, smaller than the tail blade, fixed parallel to the spinning blades. As soon as the wind reached a certain speed the additional blade pushed the turbine out of the wind direction thus lowering the speed of the blades. I also need to say that the tail was attached to the turbine with a loaded spring and when the wind reached a particular speed the fixed blade and tail blade moved towards each other. When the wind speed drops, the loaded spring pulled the tail out of position back to normal keeping the desired speed of the turbine. Simple but it worked, and maybe this method can be applied to wind turbines as well with no changes to the alternator.
Glenn Soltes

On Feb 27,28 2009 there will be a 2 day open house at True North Power in Ayr Ontario where you can see and undersatnd the technology first hand.

See http://www.truenorthpower.com for more details
http://www.chimericfire.com Nathaniel

Add an automatic transmission to the mix and see what happens. Well, I suppose it would be a reverse transmission. Basically, the idea is to have the rotors spinning at a constant speed while the gears change to provide increased power output in the higher wind speeds. Basically, the higher the wind speed, the more rotations the generator gets, but it keeps the blades spinning at a constant speed because it simply added a higher torque load to it. It’s another level of complexity, but it at least isn’t as wasteful as using that extra energy to slow the blades down.

If you’re going to go the breaking route, why not use a magnetic breaking system? Any energy overproduced is used to power the breaking system. It would be easily self-regulating and quite simple to implement.
Dylan

Hi all, Dylan again,

you all bring up good points. When I re-read my post now, I see that there are some generalizations that would end up being issues later as far as stresses, friction, life-expectancy of parts, and so on.

Thanks for all the commenting, its cool to see what everyone thinks! On a bit of a different topic, I happened to attend Highland Community College for two years and have now transferred to MATC Madison, and soon UW Madison College of Engineering. Nice timing huh? I could have been in that new wind technology program! There are now something like 64 wind generators in that area now, they started construction late this summer. Quite a site when you take a cruise on a motorcycle between classes…they seem much bigger than the turbines at Cobb, WI. The blades also seem to come to almost a knife-point, and have slight curvature.

Stay warm (its -25 here),
Dylan Manthei
Glenn Soltes

Curious … there was a post from the company that makes this system and nobody was even remotely interested.

We have a working approved system that is being rolled out to dealers in a few months
http://www.truenorthpower.com Dave Cooke

Seems like everybody missed the point. This turbine is “DEAD SIMPLE” . . it’s the sophisticated controller that makes it work. The controller uses the excess electromagnetic braking capacity of the alternator to actively “Fly” the blades at the optimum power without over-speeding or over-heating and with NO MECHANICAL FURLING system needed. It does it under microprocessor control millisecond by millisecond. The 400gram blades are FIXED but adjustable in pitch to suite the location. Low wind or High wind. Low altitude or High altitude. . .It makes a kilowatt at 25mph . . and 500w safely at 60mph but you say . . Who cares about high speed wind? . . everyone, if the turbine cannot survive a storm. The WIND ARROW can not only survive in 60+ miles/hour but goes one better . . It produces 500 watts as well, and can shut down automatically if it senses impending over-speed. If you’re worried about the storm outside just flip the switch on the controller and it stops with no stress on the tower or the blades. With only 2 bearings as moving parts with a sealed metal/lubricant contact, it is inherently more reliable that anything with additional mechanical complexity.

All the discussion about torque and transmissions and dumping excess energy is missing the point. A small wind turbine that needs no furling system and can look after itself under all wind conditions is a technological BREAKTHROUGH! Hope that helps explain things better. Thanks for all the comments.
http://www.ironmanwindmill.com Tom Conlon

The basic concept mentioned here – controlling speed by generator loading was tested widely in the 1970’s and is hardly new. It was quickly chucked out when it became apparent that electronic components, wire connections, slip rings, controllers and generators fail and that their is really nothing that can be done about this. They usually fail when they are under the highest load, hence when over speed protection is needed most. This idea will work until the first day or night when there is a serious wind storm and then the phone in the office will not stop ringing because allot of people will be calling wanting their money back because their wind turbine is spread across the countryside.

The best innovation starts when it is based on a strong understand of history and what didn’t work and why. If you want to know how to make something work, study why it can fail.
Sirandar

Many previously discarded ideas become viable as technology advances and new ideas are blended in.

It is interesting that you state that this idea and design in not viable or reliable without ever seeing actually seeing it.

That is a sign of a person with a very closed mind or a very strong vested interest in the status quo. Which one are you?
http://www.truenorthpower.com Dave Cooke

Whatever was being “tested widely in the 70’s” was not how this turbine operates because the patent for “Pulse Wind Modulation” was only granted in 1984. So I’m not sure what technology was so widely tested a decade before.
http://www.facebook.com/jthorn001 Jeff Thor

I wonder why there are not more units for sale considering the technology is there although the knowledge is hidden. More manufacturers are needed? Seems like the “coefficient of lift based turbine” should be applied to rivers, etc.. The density of water is at least 10x > then air so…. Also, all the general technical data should be published and readily accessible from government organizations such as DOE.
walter

Ok yes, but how do you build a lolly shaft to prevent the motor from twisting the wires?