WO2011138094A1

WO2011138094A1 - Method and arrangement for regulating pressure in a plain bearing of a wind power generator

Info

Publication number: WO2011138094A1
Application number: PCT/EP2011/054927
Authority: WO
Inventors: Randolf Mock; Georg Bachmaier
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-05-06
Filing date: 2011-03-30
Publication date: 2011-11-10
Also published as: DE102010019535A1; DE102010019535B4

Abstract

A method for regulating pressure in a plain bearing (12) of a wind power generator (1) is described, having the following features: model-based reconstruction of the wind power at at least one rotor blade (2) of a wind power generator (1) on the basis of signals which are supplied by at least one actuator (13, 14, 15), which has the effect of a sensor and is arranged on the at least one rotor blade (2), and thereby determining external forces acting on the at least one actuator (13, 14, 15), and calculation of the moment of force and torque at the location of the plain bearing (12), position-dependent calculation of the distribution of pressure over the circumference of the plain bearing (12) and of the activation of at least one actuator unit (7) for regulating the pressure of a hydraulic fluid in the plain bearing (2) with at least one actuator unit for regulating the bearing pressure in order to minimize operating periods with dry friction or mixed friction.

Description

description

Method and arrangement for pressure regulation in a sliding bearing of a wind power generator

The invention relates to a trained as a plain bearing

Main bearing of a wind power generator. The sliding bearing has various features and is referred to as hydrostatic / hydro ^¬ dynamic sliding bearing. In the main bearing the drive shaft is mounted, which is connected on the one hand with the rotor blades and on the other hand with a generator.

Wind power generators are usually exposed to strong wind loads. The heaviest loads occur especially in gusts that can abruptly change their strength and direction. This is particularly the case when the wind power generators are used in so-called offshore installations. Such demanding loads filters for the adjacent the Ro ^¬ door leaves main bearing a substantial burden, wherein occurring at this point forces and moments can be so strong that, for example, in Hydrosta ^¬ tables Storage of the oil film can be compressed and to dry or mixed friction comes in the area between shaft and bearing shell. The resulting dry friction leads to heavy wear of the bearing. Under certain circumstances, this can lead to the failure of the same and to the standstill of the wind power generator.

A measure to counteract this phenomenon consists in the corresponding design of the surface coating and further in the material pairing, on the one hand on the shaft and on the other hand on the bearing shell. However, this does not solve the actual problem that, at times, contact between the shaft and the bearing shell can not be fundamentally ruled out. A failure of a wind power generator in the hurricane season, for example in autumn and in winter, due to overloading can thus continue to occur, since the entire wind power generator during this time high loads from is set. Since in this period, which lasts about half a year, no repair can be performed, the wind turbine must be shut down in case of failure and remains in this state until the next repair option. This has a corresponding negative impact on the yield of the defective wind turbine.

Existing measures for solving the above-mentioned problem include, for example, using sufficiently powerfully dimensioned rolling bearings. Since such rolling ^¬ bearings, however, are made of one piece, the failure of such a bearing means disassembly of the rotor blades with lifting out of the shaft and complete, defective bearing out of the gondola of the wind power generator and the subse- quent replacement of defective parts. However, since these parts are located in the range of 100 tons, a derarti ^¬ ge repair, especially in offshore facilities associated with extremely high costs. For example, floating crane platforms with adequate load-bearing capacity must be provided, which entails very high costs.

Another possibility for improvement provides that the La ^¬ ger, which are positioned in the nacelle, can be partially dismantled, so not the complete bearing with the shaft must be dismantled for repair purposes. These seg ^¬ mented bearings are usually hydrostatic bearings. In this case, there is a gap between the shaft and the bearing shell, in which a pressurized fluid is present. From US 005513917 A, for example, a construction is known in which a corresponding bearing is acted upon in segments by pressure ^¬ . In such designs of sliding bearings the above problems, such as Tro ^¬ ckenreibung occur on the same way. In general, the bearing is heavily loaded in the radial direction. In the axial direction, one can usually make do with simple bearings in which the metallic construction is coated with, for example, a plastic coating. The heavily loaded main camp of the central shaft is subdivided according to the above-cited America ^¬ African Patent Application in over the circumference of the shaft divided segments. The partial bearings and the support ^¬ structure are designed to optimally support the rotating shaft. Said document discloses in particular ^¬ sondere an active hydrostatic / hydrodynamic bearing in which the pressure prevailing in the individual segments Fluiddrü- be adjusted dynamically active blocks. By using appropriate valves in the individual supply lines to the individual elements of the bearing, a defined pressure in each bearing segment can be adjusted, whereby on the shaft a total of a support or bearing force can be applied.

From the WO 2004/088130 Al is known that can be considerably impressive ^¬ influence by changing the wing shape and the rotor blades by fast actuators, such as piezoelectric actuators, the dynamic behavior of the rotor blade.

The sensory effect of electromagnetic or piezoelectric actuator systems is known. These can be used, for example, not only to produce electromechanical effects, but also to detect electrical forces acting on the actuators external forces. Such recorded Informa ^¬ tions can register external system quantities and are. Thus, the deformation can be an in ^¬ jektors use in conjunction with the deformation of an actuator with high accuracy as the basis for the injected fuel amount ^¬ in an internal combustion engine, for example. The actuator drives an injector in the engine.

The object of the invention is to provide a method and an arrangement by means of which extremely disadvantageous dry-running phenomena on sliding bearings in wind power generators can be minimized. The solution of this task is done by the respective Merk ^¬ malskombination of independently formulated claims. Advantageous embodiments can be found in the dependent claims.

The invention is based on the recognition that the Chamfering ^¬ wetting of the sensory effect of actuators in combination with the model-based reconstruction of the wind turbine at one or more preferably on all rotor blades of a regulation-of the pressure distribution of the hydraulic fluid in the sliding bearing or the main bearings of a wind power generator allows so that in case of uneven wind load of the wind power generator by appropriate pressure regulation of a hydraulic fluid in the sliding bearing, the contact between the shaft and bearing shell is minimized or turned off. For this purpose, force and moment at the location of the plain bearing are calculated and the pressure distribution at the circumference of the guide bearing is calculated position-dependent. The setting of a predetermined pressure for the storage pressure regulation takes place via at least one actuator unit for pressure regulation.

Particularly advantageous is the design of the sliding bearing in segmented form. This is advantageous in terms of segmental setting of a respective hydraulic pressure for each segment and further beneficial for Reparaturzwe ^¬ blocks. The segmentation allows the expansion of individual segments without the replacement of the entire sliding bearing unit. The per segment adjustable fluid pressure in the plain bearing ensures each a defined pressure in the bearing segment, which can be constructed over all bearing segments summed a defined Kraftvek ^¬ gate on the shaft. The use of the model-based reconstruction of internal state variables is advantageous. This exploits that sensory infor mation ^¬ actuators can be tapped on their electrical connection side, the actuators themselves are used to control, for example, the mechanical adjustment of a rotor blade. From this context results a substantial advantage, which consists in that actively regulated Actuators or rotor blades already have an actuator system with at least one actuator per rotor blade. If the existing actuators have a sensory effect, this, for example, the direct piezoelectric effect or the counter-induction effect of electromagnets, without the installation of sensor hardware, provide usable signals for modellba ^¬ sierten reconstruction of wind power.

Depending on the wind fields acting on the rotor, it is advantageous to obtain information through the sensory effect of actuators at the leading edge of a rotor blade or from the trailing edge of the rotor blade. The wind field along example ^¬ the trailing edge of each rotor blade flows along the rotor blade and exerts a force thereon, which is detectable via an adjustment mechanism, which is driven for example by a pie ^¬ zoelectric actuator. An electrical signal generated via the sensory effect is processed on the basis of a model-based control strategy, and as a result, the prevailing wind speed can be determined. In particular, the forces and moments acting on the rotor blade can be reconstructed.

Particular advantages arise, if the spatial distribution of the actuators is provided in the rotor blade so that Informa ^¬ functions are provided from the entire area of the rotor blade or the wind field is available. This information can be used to calculate a model-based method, such as changes in the strength, direction and distribution of the wind field, and forces and moments at the location of the wind field

Slide bearing change over time. This results in particular advantages for existing systems in that the existing actuators can be used without further modification of the system and the sensory effect of already installed actuators can be exploited. According to the invention, the modellba ^¬ catalyzed reconstruction caused by wind forces or torques being tracked. Since slide bearings are generally subject to a leakage rate, it is advantageous to take this leakage rate into account when controlling an actuator unit for regulating the pressure of the fluid in a slide bearing.

In the following, exemplary embodiments will be described with reference to the accompanying schematic figure, which does not limit the invention: In the single figure, a wind power generator is shown, which is arranged on a vertical mast.

The wind power generator 1 here has three rotor blades 2, which are arranged rotatably on a shaft in a plain bearing 12, the main bearing. The slide bearing is a conventional hydrostatic / hydrodynamic bearing, since it has features of ^¬ the bearing types.

The attached to the rotor blades 2 actuators 13, 14, 15 are positioned on the front sides of the rotor blades 2. This allows on the sensory effect of an actuator, game, the wind will be reconstructed based on a model at the corresponding position at ^¬. If an actuator can also be positioned on the rear side of a rotor blade and thus on the spoiler edge, the wind force can be reconstructed model-based at this position. The mechanical actuating mechanism of the considered actuator should be able to function as before. Also shown in the figure is a wind field 3, which acts on a rotor blade 2. This is to be regarded such that acting on each rotor blade, a wind box 3, wherein a homogeneous wind field applied to the rotors total gleichmä ^¬ a resident of the rule.

According to the invention, model-based re ^¬ construction 4 of the wind power can be operated on the rotor blade. Following this, the calculation 5 of force and torque ment at the location of the slide bearing 12. The then following calculation ^¬ voltage 6 relates to the determination of the position on the circumference of the sliding bearing 12 in connection with the distribution of pressure in the hydraulic fluid. Output signals of the evaluation unit 16 pass over the control line 11 to the actuator unit 7, which regulates the pressure regulation of the fluid in the slide bearing 12.

The data lines 8, 9, 10 supply the evaluation unit 16 with signals of the actuators 13, 14, 15, wherein the signals have been generated via the respective sensory effect. It should be noted that the number of per rotor blade 2 pre ^¬ existing actuators may be arbitrary. In the accompanying figure, only one actuator is specified. In order to utilize the sensory effect of, for example, electromagnetic or piezoelectric actuator systems, the viewpoint applies that information about system-external variables can be obtained in the operation of the actuators via the forces acting on the actuators. So z. For example, the deformation of a fluid injector containing an actuator is one

Dependence on the quality and accuracy of the fluid injection. This can be detected by means of model-based control strategies, wherein the information about the injected fuel ^{quantity ¬} from the deformation of the injector and thus the actuator contained therein with high quality and accuracy is reconstructed.

The method of model-based reconstruction of external variables can also be applied to active rotor blades. The wind field, which flows along, for example, the trailing edge ei ^¬ nes each rotor blade exerts on this a force which is transmitted via an adjustment mechanism, for example, a piezoelectric actuator is used to adjust the rotor shape. About the sensory effect an electrical signal is generated from which on the basis of a model-based control strategy, the information about the prevailing on the rotor blade edge wind speed is rekon ^¬ struierbar. It will be beneficial to the respective Rotor blade acting forces and moments, in particular Torque ^¬ elements, reconstructed.

Moreover, it is possible to obtain a spatial distribution of the actuators in the wind field 3 or on a rotor blade, Informa ^¬ functions about the way in which the wind field develops on a rotor blade. With this information, model-based calculations can be used to determine how changes in the wind field cause temporal changes in forces and moments at the location of the plain bearing.

On a known, active hydrostatic / hydrodynamic bearing, controlled variables can be derived from the sensory information of actuators with which the pressure distribution within the bearing can be actively controlled. The objective is to absorb sudden ^¬ Liche force or torque changes, in particular gusts of wind in such a way or take countermeasures that the frequency of contact between the shaft and the bearing shell is mini mized ^¬, or is turned off.

A significant advantage in the utilization of sensory information of actuators active rotor blades for controlling the pressure distribution in the main bearing / plain bearing of a wind turbine is due to the fact that no further sensors are necessary to evaluate important dynamic information about forces and moments at the location of the plain bearing , By increasing the number of actuators, the entire system would become more complex and at the same time more prone to ^errors .

Claims

claims

1. A method for pressure control in a sliding bearing (12) of a wind power generator (1) comprising the following steps:

- Model-based reconstruction of the wind force on at least one rotor blade (2) of a wind power generator (1) on the basis of signals from at least one actuator (13, 14, 15) having a sensory effect on the at least one rotor blade (2) is arranged, and whereby on the at least one actuator (13, 14, 15) acting external forces are determined;

- Calculation of force and torque at the location of the plain bearing (12);

- Position-dependent calculation of the pressure distribution at the periphery of the sliding bearing (12);

- Actuation of at least one actuator unit (7) for Druckre ^¬ gelung a hydraulic fluid in the sliding bearing (2).

2. The method according to claim 1, characterized in that the sliding bearing (12) is segmented.

3. The method according to claim 2, characterized in that the fluid pressure in the sliding bearing (12) is adjustable in segments.

4. The method according to claim 3, characterized in that by summing all segment pressures, a resulting force vector results in the bearing mounted in the shaft bearing.

5. The method according to any one of claims 1-4, characterized in that is used as the sensory effect of the direct piezo ^¬ electrical effect of piezoelectric actuators or the counter-induction effect in electromagnets.

6. The method according to any one of the preceding claims, characterized in that the rotor blades (2) of the wind power generator (1) are actively adjustable by actuators (13, 14, 15).

7. The method according to any one of the preceding claims, characterized in that a plurality of actuators at the front edge of the at least one rotor blade (2) are distributed.

8. The method according to any one of the preceding claims, characterized in that the temporal evolution of force and moment on the at least one rotor blade (2) is calculated.

9. The method according to claim 8, characterized in that based on the temporal evolution of force and moment on the at least one rotor blade (2) can perform the model-based calculation of forces and moments at the location of the sliding bearing (12) as a function of time ,

10. The method according to any one of claims 1-9, characterized in that for the actuation of actuators to build up hydraulic pressure in the sliding bearing, the leakage rate of the sliding bearing is taken into account.

11. The method according to any one of claims 1-10, characterized in that a plurality of actuators at the trailing edge of a Ro ^¬ torblattes (2) are distributed.

12. An apparatus for performing a pressure control in a sliding bearing (12) of a wind power generator (1), comprising the following components:

a first evaluation unit for processing signals from actuators located on different rotor blades for the model-based reconstruction of the wind force on the respective rotor blade,

a second evaluation unit for calculating the force and the moment at the location of the plain bearing (12),

a third evaluation unit for calculating the pressure distribution to be set in the slide bearing 12 relative to the circumference of the sliding bearing 12, - At least one actuator for pressure control of a hydraulic fluid in the sliding bearing (2) to minimize operating times with dry or mixed friction.

13. The apparatus according to claim 12, characterized in that a plurality of actuators at the front edge of a rotor blade (2) are distributed.

14. The apparatus of claim 12 or 13, characterized in that for the fluidic control of individual segments of the sliding bearing (2) quickly switching valves in the Zulei ^¬ lines are available.