The Vindicator^TM laser wind sensing system, from Catch the Wind Ltd., the United States, measures real-time horizontal and vertical wind speed and direction data at varying ranges ahead of the sensor location. The system comprises a fibre optic laser module, processor, control system interface and a remote lens assembly. The laser module and processor are in a separate assembly that may be located within the wind turbine nacelle or with the remote lens assembly.

Using concepts of Doppler radar, with light as the medium of detection, the Vindicator system quickly senses air particle movement. The system processor analyses the air particle movement, producing speed and direction data for wind field determination. The first production variant of the system will sense the wind out to 300 m; longer ranges can be incorporated, if needed.

The Vindicator works by integrating with a wind turbines control system. The fibre optic lasers sense the wind that is approaching the turbine at a range of 300 m and report this to the control system in sufficient time to adjust and orient the turbine. Using control algorithms, the control system will decide how best to exploit the wind and direct internal systems to either change blade pitch and/or re-orient the nacelle to maintain efficiency, reduce the effects of wind shear and gusts, or maintain a constant blade speed. Contact: Mr. Bill Fetzer, Director of Business Development, Catch the Wind Limited, 10781 James Payne Court, Manassas, VA 20110, United States of America. Tel: +1 (703) 393 0754; E-mail: wfetzer@catchthewindinc.com.

Source: www.catchthewindinc.com

In the United Kingdom, BroadStar Wind Systems has introduced the AeroCam, a radical new design in wind turbines. The innovative AeroCam turbine uses horizontal blades arranged in a rotating cylindrical structure, which can be placed on buildings or to infill existing wind farms. With its parallel rotor blades giving it the appearance of a water wheel, it not only looks radically different from traditional windmill designs, but is also more aerodynamically efficient, smaller and more compact.

The main technical innovation in the AeroCam design is its ability to continually adjust the pitch of its rotor blades to an optimum angle as the turbine rotates. This unique active pitch control capability helps optimize its aerodynamic performance for the same reasons a bird changes the shape of its wings in flight. Consequently, AeroCam can handle a wide range of wind velocities, between 6 km/h and 130 km/h. It also generates its power at lower rotational speed; there is hence less noise and vibration, and less wear and tear. AeroCam has a very low start-up speed, requiring a wind velocity of just 6 km/h, and it starts generating power at an unprecedented 8 km/h, according to BroadStar.

Source: www.marketwatch.com

WindLift LLC, the United States, is looking to fly kites to produce power. The company plans to build a kite package that costs US$5,000, will climb up to 300 feet in the air and produce 10 kW of power. The ideal application for the initial version of their kite power package is water pumps and irrigation systems in off-the-grid locations, said WindLift founders Mr. Robert Creighton and Mr. Bart Bartlett. The kite provides about a kilowatt per metre for a 5-20 metre kite.

Launching the WindLift kite is very much the same process used for normal kites, which can be done in about 5-10 minutes in 6-10 mph winds. Once the kite is in the air, it will be able to fly by itself; when the wind dies down it will be automatically reeled in. Contact: Mr. Robert Creighton, CEO, WindLift LLC., 3825 S. Roxboro Street, Suite 136-251, Durham, NC 27713, United States of America.

Source: www.earth2tech.com

Windation Energy Systems Inc. of the United States has developed a new wind power machine inspired by a centuries-old idea: the Persian wind catchers. The wind appliance has a 8 ft 8 ft frame around a 10 ft high cylinder. Wind blows at the top and is directed to the bottom where it turns a turbine to generate up to 5 kW of electricity.

Mr. Mark Sheikhrezai, Windation CEO and founder, said he was inspired by ancient Persian buildings that use air currents and reservoirs of water to cool buildings. Using differences in air pressure, these wind catcher buildings create a steady flow of air without any mechanical devices. Although Windations wind appliance does draw air from the top like these buildings, Mr. Sheikhrezai used his expertise in rotors and centrifuges to coax the flow of the wind to generate electricity. As all moving parts are enclosed, there is no potential danger to bats, birds or people. The units will work well with gusty, inconsistent wind, Mr. Sheikhrezai said.

Source: www.smartplanet.com

In Spain, an engineer at the Public University of Navarre has developed two new methods to protect wind generators during voltage dips. In his Ph.D. thesis, Mr. Jess Lpez Taberna describes a rotor model that anticipates how a wind power unit will behave in these situations. One of the protection techniques, which has already been transferred to a manufacturer, allows the generator turbine to remain in operation during these voltage dips and thus prevent the wind energy converter from ceasing to function.

The growth and development of wind energy converters has been slowed by problems that have arisen from the increase in the number of these connected to the electric grid. One of the most important problems is precisely the manner in which the wind generators behave during voltage dips, which happens in a few milliseconds. But, for a machine, this can be an eternity, explained Mr. Lpez. In fact, an interruption of half a second in a productive process can cause the whole process to seize up.

With wind generators, voltage dips can cause the electronic part of the unit to burn out. The current protection system, the Crowbar, protects the machine but it also halts it, thus causing the generators to cease producing electricity. As a result, the power dip is even more accentuated and, consequently, it is even more difficult to bring the voltage up to its normal operating value.

Mr. Lpez produced a rotor model to study the role each parameter of the machine plays, how they interact, how the current drops if we increase the leak inductances and so on. With this model, it is more or less easy to propose solutions. Mr. Lpezs second system of protection, also patented, continues to be developed for applications in new generations of wind turbines.

Source: www.engineerlive.com

ExRo Technologies Inc., a Canadian start-up company, has developed a new kind of generator that is more efficient in harvesting energy from wind. As the new generator runs over a wider range of conditions than conventional generators do, it could lower the cost of wind turbines while increasing their power output by 50 per cent.

When the shaft running through a generator is turning at the optimal rate, more than 90 per cent of its energy can be converted into electricity. If it speeds up or slows down, the generators efficiency drops dramatically. This is a problem in wind turbines, as wind speed can vary wildly. ExRos new design replaces a mechanical transmission with an electronic one. That increases the range of wind speeds at which it can operate efficiently and makes it more responsive to sudden gusts and lulls. While at the highest wind speeds the blades will still need to be pitched to shed wind load, the generator will allow the turbine to capture more of the energy in high-speed winds. As a result, the turbine can produce 50 per cent more power on average over a year, says Mr. Jonathan Ritchey, ExRos Chief Technology Officer.

In ordinary generators, all coils are wired together. In ExRos generator, in contrast, the individual coils can be turned on and off with electronic switches. At low wind speeds, only a few of the coils will switch on to efficiently harvest the small amount of energy available. At higher wind speeds, more coils will turn on to convert more energy into electricity. The switching is quick enough to suit fast-changing wind speeds.

Instead of arranging all coils inside a very-large-diameter generator, the ExRo generator distributes the coils among several small-diameter generators, in stacks along the length of the shaft. This keeps the rotor on which the magnets are mounted small, making it easy to get it moving or to change its rotation speed. The multiple-stack design also facilitates customizing the generator for a particular wind site easier. Contact: Exro Technologies Inc., 200-1847 Marine Drive, West Vancouver, British Columbia, V7V 1J7 Canada. Fax: +1 (604) 925 9961; E-mail: info @exro.com.

Source: www.technologyreview.com