Optimising the control of wind generators by means of intelligent microsensors

April 24, 2006

The School of Engineering at Bayonne (ESTIA) is working on a research project on control optimisation for the latest-generation wind generators using intelligent microsensors.

The latest-generation wind generators work at variable speed and with pitch regulation based on the pitch angle of the rotor blades. These degrees of freedom (the rotation speed and the pitch angle of each blade) enable an increase in energy yield, a decrease in fatigue due to mechanical loads and an enhancement in the quality of the electrical potential with respect to fixed-speed wind turbines. The rotation speed and the pitch angle of the blades are controlled continuously by control algorithms and the quality of these algorithms have a determining influence on the price of the energy produced by the wind generators. Although a large amount of research work on wind generator control has been undertaken, it still remains for more "intelligence" to be introduced into their functioning.

The reduction in the price of wind energy is made possible through:This weight reduction can be achieved only by reducing the mechanical forces on the blades, the transmission axle and the tower. Moreover, the current trend in increasing the size of wind generators means having mechanically more flexible machines. The control has to take into account this flexibility, especially avoiding the resonance frequencies of the various mechanical elements.

Thus, the classical criteria linked to the optimisation of control algorithms for variable-speed and pitch-regulated wind generators are:Within the framework of this question, the ESTIA School of Engineering is particularly focusing on criteria dealing with the reduction of the mechanical stresses arising from fatigue in the elements of a wind generator (tower, blades, transmission axle/gearbox).

Fatigue in a wind generator's elements is mainly linked with the external dynamic forces that these parts undergo and with the fluctuations in their resonance frequencies. Control of the wind generator should enable an overall reduction in these stresses in order to increase reliability and, thereby, the usefulness of wind generators, and enable a reduction in the overall weight of their components. The main loads are those withstood by the blades, the tower and the transmission axle/gearbox. The design of the control algorithms has to take into account this reduction in the mechanical stresses in these components. Several degrees of freedom exist in order to achieve this target: the two of the electric motor, the pitch angle for each blade (three for the classical wind generator) and the orientation (the "yaw") of the whole turbine with respect to the tower axis. This last parameter is not within the remit of this current research project.

The design of this control should take into account not just one of the four criteria previously mentioned. Although the main objective here is the reduction of dynamic stresses experienced by the wind generator, the other criteria are not forgotten.

Intelligent microsensors (acceleration sensors with wireless communication) located at the blade tips, above the surface of the wind generator axis and in the tower will be used to optimise the control.

Thanks to these acceleration sensors, the control system will have supplementary information in real time, thus enabling reduction in fatigue stresses using multivariable optimisation algorithms.

Commercial wind generators are fitted with a number of sensors (voltage, current, rotation velocity, etc.). Nevertheless, they are currently not fitted with acceleration or with stress sensors.
-end-


Elhuyar Fundazioa

Related Fatigue Articles from Brightsurf:

Got fatigue? Study further pinpoints brain regions that may control it
Scientists at Johns Hopkins Medicine using MRI scans and computer modeling say they have further pinpointed areas of the human brain that regulate efforts to deal with fatigue.

Biomarkers link fatigue in cancer, Parkinson's
Biological markers responsible for extreme exhaustion in patients with cancer have now been linked to fatigue in those with Parkinson's disease, according to new research from Rice University.

Fatigue is a common but underestimated symptom of endometriosis
Two papers published in Human Reproduction journal show that the prevalence of fatigue is more than doubled in women with endometriosis but is underestimated, meaning that doctors should be making greater efforts to discuss and treat this debilitating symptom in these women, and that a history of some types of child abuse is linked to an increased likelihood of endometriosis in adulthood.

New 3-D display takes the eye fatigue out of virtual reality
A new type of 3-D display could solve the long-standing problem eye fatigue when using VR and AR equipment by greatly improving the viewing comfort of these wearable devices.

Chronic fatigue syndrome linked to imbalanced microbiome
Scientists at the Center for Infection and Immunity (CII) at Columbia University's Mailman School of Public Health have discovered abnormal levels of specific gut bacteria related to chronic fatigue syndrome/myalgic encephalomyelitis, or ME/CFS, in patients with and without concurrent irritable bowel syndrome, or IBS.

Conquering metal fatigue
Researchers have found a way to greatly reduce the effects of fatigue in steel by incorporating a laminated nanostructure into the material.

Anakinra does not seem to improve fatigue severity in women with chronic fatigue syndrome
The anti-inflammatory biologic drug anakinra does not seem to reduce fatigue severity in women with chronic fatigue syndrome.

Reducing cancer-related fatigue
A new article published online by JAMA Oncology analyzed which of four commonly recommended treatments -- exercise, psychological, the combination of both, or pharmaceutical -- for cancer-related fatigue appeared to be most effective.

Urine test for fatigue could help prevent accidents
Doctors, pilots, air traffic controllers and bus drivers have at least one thing in common -- if they're exhausted at work, they could be putting lives at risk.

Genetic cause for shift work fatigue discovered
Some people adapt easily to shift work, but not everyone can handle constant disruptions to their daily rhythm.

Read More: Fatigue News and Fatigue Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.