Patent Application
20170089327
Technical Field
The present disclosure relates to a wind turbine rotor blade and to a heating unit for a wind turbine rotor blade.
Description of the Related Art
The rotor blades of a wind turbine are exposed to the forces of nature unprotected. Both the rotor blades and the wind turbine as a whole must be able to operate in a wide temperature range. However, particularly at temperatures around or below freezing, icing of the rotor blades may occur. There are some existing known methods for heating rotor blades (for example by air heating) and for deicing the rotor blades or for preventively avoiding icing.
DE 10 2011 086 603 A1 discloses a wind turbine rotor blade and a method for deicing a wind turbine rotor blade by means of air heating.
In the priority-establishing patent application, the German Patent and Trademark Office has searched the following documents: DE 10 2011 086 603 A1, DE 100 16 259 C2, DE 10 2004 042 423 A1, JP 2001-122533 A, EP 2 386 750 A1, DE 10 2009 039 490 A1.
Electrically operated heated mats, which have at least one electrical line as a heating element, may be used as an alternative to this. The use of electrical lines in the heating mat, which is then placed in the rotor blade or is integrated in the rotor blade, is however disadvantageous with regard to the risk of a lightning strike.
Embodiments of the present disclosure provide a wind turbine rotor blade and a heating element for a wind turbine rotor blade that reduces the risk of a lightning strike.
Consequently, a wind turbine rotor blade with a heating unit for heating the rotor blade is provided. The heating unit has at least one optical waveguide as a heating element. The heating unit has at least one connection for an energy or light source or an emitter, which can emit energy in the form of electromagnetic beams or waves, for example light, through the optical waveguide. The electromagnetic waves are converted into heat by the attenuation losses of the optical waveguide.
The attenuation of the optical waveguide is optionally chosen such that the electromagnetic beams or waves coupled in by way of the light source or the energy source, for example light, are converted into heat as uniformly as possible over the length of the optical waveguide.
According to one aspect of the present disclosure, a heating unit is integrated in the rotor blade or is attached to the rotor blade.
The heating unit may also be designed as a mat, for example a silicone mat, that has a plurality of optical waveguides which on the basis of their attenuation, convert electromagnetic waves conducted through them, for example light, into heat. This heat can then be used for warming or heating a rotor blade.
Consequently, the optical waveguides used according to the disclosure do not necessarily correspond to the optical waveguides that are usually used for optical data communication, which are designed such that the attenuation is minimized. While the attenuation is undesired in the case of optical data communication, the attenuation of the optical waveguides according to the disclosure is desired, in order to be able to heat the rotor blade.
The disclosure likewise relates to a heating unit for a wind turbine rotor blade. The heating unit has an input connection for coupling in electromagnetic waves, for example light, and at least one optical waveguide as a heating element. The heating unit may optionally be designed as a mat with an input connection. This allows the mat to be integrated in the rotor blade or attached to its inner side. The mat may be integrated into the material of the rotor blade.
The heating unit may optionally be arranged as close as possible to the outer surface of the rotor blade, in order to be able to heat the outer region in particular.
According to one aspect of the present disclosure, the attenuation is chosen such that there can be a uniform heat dissipation along the length of the at least one optical waveguide.
A grid of optical waveguides may be optionally provided in the rotor blade or in the heating unit.
The solution according to the disclosure is advantageous because with it both lightning strikes and static electrical charging can be avoided or reduced. The optical waveguides typically serve for the transmission of light and consist of fibers, such as for example quartz glass or plastic (polymeric optical fibers). This allows the optical waveguides to be integrated very well into the conventional structure of the blade, for example consisting of GRP or CRP. Furthermore, the optical waveguides behave uncritically with respect to durability.
Further refinements of the disclosure are the subject of the subclaims.
Advantages and exemplary embodiments of the disclosure are explained in more detail below with reference to the drawing.
In
According to the disclosure, one coupling-in unit or multiple coupling-in units may be provided for the coupling in of light. The coupling-in unit is preferably provided in the region of the rotor blade root or in the region of the rotor blade hub. The optical waveguides may optionally be arranged as close as possible to the outer surface of the rotor blade, in order to warm this region in particular.
The disclosure is based on the idea of using optical waveguides as heating elements for a heating unit of a rotor blade. This initially appears to be counter-productive, since optical waveguides are typically designed such that the attenuation is minimized. However, the disclosure concerns the idea of designing the attenuation of the optical waveguides such that part of the amount of light provided in the waveguide is converted into heat and can thereby warm the rotor blade.
The disclosure likewise relates to a heating unit with optical waveguides as a heating element (as described above), the heating unit being used for example as heating for the seats in a car or the like.
The sensor or the measuring instrument unit 400 has a coupling-out unit 410 for receiving the electromagnetic waves, for example in the form of light, by way of the optical waveguide 640 and for converting these electromagnetic waves into electrical energy. The function of the coupling-out unit 410 consequently corresponds substantially to the function of a photovoltaic unit or a photoelectric unit, since this unit converts the received electromagnetic waves, for example light, into electrical energy. The sensor or the measuring instrument unit has a corresponding sensor 420 and an optical transmitter 430. The transmitter 430 can convert the electrical output signals of the sensor 420 into optical signals and can pass these signals on to an optical receiver 650 by way of the optical waveguide 640 or 641.
Consequently, the optical waveguides 640 are used in the direction from the coupling-in unit 630 to the sensors or the measuring instrument units for supplying energy and are used in the direction from the sensors or the measuring instrument unit to the receiver 650 for data transmission of the output signals of the sensors.
The receiver 650 receives the optical signals from the optical transmitters 430 by way of the optical waveguides 640, 641 and converts these signals into electrical signals. The electrical signals are then fed to an evaluation unit 620.
The evaluation unit 620 may pass on the evaluated measuring signals of the sensors and/or of the measuring instrument units 400 to a central controller 500, which on the basis of the measuring signals recorded can intervene in the operation of the wind turbine. This may take place for example by changing the pitch angle of the wind turbines, by changing the azimuth angle or the like.
According to one aspect of the present disclosure, the coupling-in unit 630 and/or the receiver 650 may likewise have an optical transmitter, by means of which data signals can be transmitted to the sensors 400. This data communication may take place for example for controlling the sensors and/or the measuring instrument units 400.
The coupling-in unit 610 and/or the evaluation unit 620 may be provided in the region of the rotor blade root 220 or in the region of a hub of the wind turbine.
With the coupling-in unit 610, for example, electrical energy can be converted into optical signals, and consequently optical energy. This optical energy may be transmitted by means of the optical waveguides 630 to the sensors and/or the measuring instrument units. In the sensors and/or measuring instrument units, the coupled-in optical energy may be converted by means of the coupling-out unit 410 into electrical energy, which can then be used for supplying energy to the sensors 400. Optionally, the sensors 400 may have an energy store, for example in the form of at least one capacitor.
The transmitter 430 is designed for converting the electrical output signals of the sensors 420 into optical signals with defined amplitudes and/or frequencies and then transmitting these optical signals by way of the optical waveguides to the optical receiver 650.
In the evaluation unit 620, the measuring signals of the sensors and/or the measuring instrument units 400 may for example be subjected to a spectrum analysis.
The sensors 400 may for example have strain gauges as sensors 420.
With a rotor blade according to the disclosure that has an energy transmission for the sensors and/or measuring instrument units on the basis of optical waveguides, the risk of lightning strikes and/or static charges is significantly reduced because there are no electrical lines.
Since the optical waveguides are typically glass fibers, integration of these optical waveguides in the material of the rotor blade is uncritical. In particular, the optical waveguides and the fiber composite materials that are typically used in the case of rotor blades have the same coefficients of expansion.
According to the disclosure, a coupling-in unit or multiple coupling-in units may be provided for the coupling in of light. The coupling-in unit is preferably provided in the region of the rotor blade root or in the region of the rotor blade hub.
The physical variables that can be measured by the sensors 400 are for example acceleration, speed, blade loading, blade stress, temperature, air pressure, atmospheric humidity, blade bending, torque, etc.
According to the third exemplary embodiment, the optical waveguides may be used like the optical waveguides in the first or second exemplary embodiment not only for energy transmission and data transmission but also for heating or warming the rotor blade. All that is necessary for this purpose is for the coupling-in unit 310 according to the first or second exemplary embodiment to be provided.
As an alternative to this, the optical waveguides 320, 330 according to
| Number | Date | Country | Kind |
|---|---|---|---|
| 102014204857.5 | Mar 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/055232 | 3/12/2015 | WO | 00 |
