Prime-mover dynamo plants – Fluid-current motors – Wind
Reexamination Certificate
1999-11-08
2001-09-04
Ponomarenko, Nicholas (Department: 2834)
Prime-mover dynamo plants
Fluid-current motors
Wind
C290S044000, C310S216006
Reexamination Certificate
active
06285090
ABSTRACT:
The present invention is in the area of wind turbine power production.
It concerns a system for the production concerns electrical energy activated by the force of the wind on the blades of a wind turbine.
BACKGROUND
Different types of wind turbines having an essentially vertical shaft and an essentially horizontal axis or even an essentially vertical axis are known.
The demand for energy increases constantly as fossil fuel reserves diminish.
This is why electrical companies are beginning to integrate wind turbine energy with other conventional energy sources. Thus, numerous wind turbine power stations have been installed.
Most wind turbines designed for energy production include a rapid asynchronous generator coupled to a multiplier, itself driven by the hub on which the wind turbine blades are mounted. Mention may be made especially of Micon wind turbines.
For example, a 1500-rpm asynchronous generator and a multiplier driven at a speed of 27 rpm correspond to 600 kW.
All these elements are placed in a nacelle, rotationally mounted to one end of the shaft. The height of the shaft is generally between 30 and 60 m.
Also within the nacelle is a nacelle orientation control system and, in some cases, a blade angle of attack control system. This allows the blades to be oriented as a function of the wind. In particular, if the wind becomes too strong, the pitch relative to the wind is modified for reasons of exploitation and safety.
These systems, such as the multiplier, require the presence of at least one hydraulic generator in the nacelle.
A global wind turbine control system is generally provided. It uses a controller that may control the blade angle of attack, the nacelle position, and/or the coupling of the generator to the supply network.
As the asynchronous generator has one or two fixed speeds, its operation on the supply network is not optimal over the entire range of wind speeds.
Low-speed directly driven wind turbines have also been installed. Of note are those manufactured by Enercon. They include a large-diameter radial-flux synchronous machine. The rotor disc of the machine is driven by a shaft, which, in turn, is driven by the wind turbine blades.
The synchronous machine feeds the supply network through an ac-dc-ac converter. Such a converter allows the supply network to be fed at the appropriate frequency and voltage.
In such wind turbines, all the control systems are electrical, especially those that ensure blade pitch or nacelle orientation, as well as the braking system.
These wind turbines allow dispensing with the multiplier and the hydraulic generator. They can also deliver power even at low wind speed.
However, they include an air-cooling system that generates a significant noise level.
In addition, the presence of rotor field windings implies excitation losses that become appreciable at low wind speeds, significantly diminishing the efficiency of the assembly.
Finally, the power of the synchronous machine is necessarily limited by the diameter of the rotor.
Excitation of such a machine with a wound rotor implies either the use of a set of slip rings and brushes, constraint of maintenance generators, or the inclusion of an auxiliary ac exciter and a set of shaft-mounted rectifiers, which further increase the mass of the assembly.
It may be noted also that, in general, wind turbine assembly is difficult. It requires very tall cranes able to lift heavy members of great bulk. Thus, assembly requires a significant engineering effort. For that reason, assembly of such wind turbines in countries that do not have the appropriate equipment at their disposal is not possible.
SUMMARY OF THE INVENTION
The object of the invention is the provision of a system for the production of energy associated with a wind turbine that does not require a multiplier, while facilitating construction of the wind turbine and reducing the noise generated by the wind turbine during operation.
This system for the production of electrical energy is associated with a wind turbine comprising blades fixed on a support and driving in rotation the rotor of an alternator.
This alternator is of the discoid type and consists of at least one module comprising at least a rotor disk and a stator disk centered on the axis of the blade support, the modules being assembled in such a way that all the rotor and stator disks are coaxially arranged.
The direct driving of the rotor disk(s) by the wind turbine blades renders the presence of a multiplier unnecessary and possibly permits the complete discontinuance of the hydraulic generator.
In addition, the modular design of the alternator allows for easy adaptation to system power.
The following characteristics may likewise be taken into account, individually or according to all technically possible combinations:
the system includes a shaft driven in rotation by the blade support, the rotor disk(s) being integrated with said shaft,
the blade support includes the alternator frame, which includes the alternator rotor disk(s),
a module has a rotor disk arranged, between two stator disks or a stator disk between two rotor disks,
the rotor disk or disks have permanent magnets,
the stator disks are affixed to the wind turbine nacelle,
an ac(-dc)-ac converter is placed between the alternator and the supply network,
the ac(-dc)-ac converter consists of a rectifier and an inverter, both controlled by pulse-width modulation,
the wind turbine includes a system for global control of the operating parameters.
The invention also concerns a wind turbine equipped with an energy production system in accordance with the invention and in which certain parts, especially the blades, their support, the discoid alternator, and/or the nacelle are manufactured separately and are finally assembled at the top of the wind turbine shaft.
The invention also concerns an array of wind turbines each equipped with a system for the production of electrical energy according to the invention and an ac-dc converter.
The output of each of these converters is connected to at least one dc-ac converter and the common-node output of the dc-ac converters is connected to the supply network.
The following characteristics also may be taken into account, individually or according to all their technically possible combinations:
the wind turbine array includes an energy storage system between the dc-ac converters and the supply network,
the wind turbine array includes at least one kinetic energy storage system, supplied by the dc voltage tapped at the output of the ac-dc converter(s),
the kinetic storage system(s) include(s) at least one ac motor driving at least one inertial load and powered by at least one reversible dc-ac converter, which, in turn, is connected to the output of the ac-dc converter(s),
the ac-dc converters include of a rectifier controlled by pulse-width modulation, and
the dc-ac converters include of an inverter controlled by the principle of pulse-width modulation.
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Chen et al., “A Variable-Speed, Permanent-Magnet, Wind-Turbine Generator And Its Control”, Power Engineering Conference, vol. 2, Sep. 1995, pp. 517-520.
Jefferson et al., “The Application Of Flywheels In Short-Term Energy Storage”, Alternative Energy Systems, Electrical Integration and Utilization Conference, Sep. 1984, pp. 97-104.
Brutsaert Patrick
Canini Jean-Marc
Michaux Raymond
Jeumont Industrie
Leydig , Voit & Mayer, Ltd.
Ponomarenko Nicholas
LandOfFree
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