System and method for combined testing of a rotor blade of a wind turbine and a rotor blade bearing of a wind turbine

Abstract

The invention relates to a system for combined testing of a rotor blade (2) of a wind turbine and a rotor blade bearing (3) of a wind turbine, comprising: a test bench base (1) having a test bench bearing (4) arranged on the test bench base (1), wherein the test bench bearing (4) is designed to receive the rotor blade bearing (3) with the rotor blade (2) arranged thereon such that a rotational degree of freedom for the rotor blade bearing (3) is provided by means of the test bench bearing (4); a pitch lock mechanism (7, 7') for providing a defined pitch of the rotor blade (2) with respect to the test bench base (1); a first rotational actuator (5) for applying a rotational movement to the rotor blade bearing (3) in order to test the rotor blade bearing (3); and a blade actuator (9) for deflecting the rotor blade (2) in order to test the rotor blade (2). The invention also relates to a method for the combined testing of a rotor blade (2) of a wind turbine and a rotor blade bearing (3) of a wind turbine.

Description

[0001] m and method for the combined testing of a rotor blade of a wind turbine

[0002] The present invention lies in the field of mechanical engineering. It relates to the testing of rotor blades and rotor blade bearings of wind turbines.

[0003] Testing large components of wind turbines is a complex, time-consuming and costly undertaking due to the required mechanical structures, the forces to be applied, the dimensions of the components and the high workload.

[0004] Testing new developments in wind turbine rotor blades is mandatory, and various test rigs exist to facilitate this. For example, modern test rigs now allow for the testing of rotor blades exceeding 100 meters in length. The focus of these tests is usually on the fatigue strength of the rotor blades, and the expected load cycles during the anticipated service life of the wind turbine are tested. The latest developments in test methods aim to test biaxial cycle strength, meaning simultaneously testing the fatigue-relevant cycles in the two main axis directions of the rotor blade (paw direction and pitch direction). The rotor blade bearings connected to the rotor blades are also among the functionally and safety-critical components, and manufacturers and research institutions have developed special test rigs to test these components before their use in a wind turbine.Such test facilities often use special adapters that emulate the installation situation and connection stiffnesses of the rotor blade bearings as a significant influencing factor for the test operation.

[0005] Due to the increasing size of modern wind turbines and the associated challenges, verifying and testing the functionality and design of new developments will continue to play an important role in development.

[0006] The object of the present invention is to make the testing of wind turbine components more cost-effective and efficient.

[0007] This is achieved by a system according to claim 1 or by a method according to the dependent claim. Advantageous embodiments are described in the dependent claims, the following description, and the accompanying figures.

[0008] To optimize time and costs in the real-scale testing of rotor blades and rotor blade bearings, a system or method is proposed here which enables joint testing with regard to the respective fatigue life.

[0009] The proposed system for the combined testing of a rotor blade of a wind turbine and a rotor blade bearing of a wind turbine comprises a test stand base with a test stand bearing arranged on the test stand base, wherein the test stand bearing is configured to accommodate the rotor blade bearing with the rotor blade arranged thereon, so that a degree of rotational freedom is provided for the rotor blade bearing by means of the test stand bearing.

[0010] The system also includes a pitch-lock mechanism to provide a fixed pitch of the rotor blade relative to the test stand base. Furthermore, the system includes a primary rotary actuator to apply a rotational movement to the rotor blade bearing in order to test the bearing, and a blade actuator to deflect the rotor blade in order to test the blade itself.

[0011] The proposed procedure for the combined testing of a wind turbine rotor blade and a wind turbine rotor blade bearing comprises the following steps:

[0012] Providing a test bench base with a test bench bearing arranged at the test bench base;

[0013] Attaching the rotor blade bearing with the rotor blade attached to it to the test stand bearing, so that one degree of rotational freedom is provided for the rotor blade bearing by means of the test stand bearing;

[0014] Testing the rotor blade bearing by subjecting the rotor blade bearing to a rotational movement using a first rotational actuator;

[0015] Testing the rotor blade by subjecting the rotor blade to vibrations using a blade actuator; whereby a fixed pitch of the rotor blade relative to the test stand base is provided by means of a pitch-lock mechanism.

[0016] In particular, testing of the rotor blade bearing and testing of the rotor blade can be carried out at least partially simultaneously.

[0017] These features advantageously enable the simultaneous testing of the rotor blade and the rotor blade bearing by providing, on the one hand, the rotational freedom for the rotor blade bearing, which allows for rotational stress during testing, and on the other hand, by decoupling this rotational freedom from the rotor blade and the test stand base by the additional test stand bearing. This makes it possible to generate a rotational movement of a ring of the rotor blade bearing under test and to test the rotor blade simultaneously and without restrictions.

[0018] The first rotary actuator can, for example, act on a bearing ring of the test rig bearing. For instance, the rotational degree of freedom can be provided for a hub-side bearing ring of the rotor blade bearing, which is connected to a rotor blade-side bearing ring of the test rig bearing. In this case, the rotor blade-side bearing ring of the test rig bearing and the hub-side bearing ring of the rotor blade bearing are rotationally decoupled from the test rig base and the rotor blade, in particular by connecting the rotor blade and / or the rotor blade-side ring of the rotor blade bearing connected to it with a suitable, torsionally rigid and / or flexible coupling to the test rig base. The hub-side bearing ring of the rotor blade bearing is the bearing ring that would be connected to the hub if the rotor blade bearing were integrated into a wind turbine. The first rotary actuator acts, for example, on the rotor blade-side bearing ring of the test rig bearing.However, it can also be provided that the first rotary actuator acts on the hub-side bearing ring of the rotor blade bearing.

[0019] The first rotary actuator can be electrically or hydraulically operated, for example. It can be configured to provide, for example, a cyclic rotary motion. In particular, all test modes known from the prior art can be selected. The design of the rotor blade bearing test can target various failure modes: raceway fatigue, raceway wear, structural fatigue, damage to the cages and gears, extreme loads (edge ​​bearing, core failure, fracture), etc.

[0020] The rotational movement for checking the rotor blade bearing can take place particularly when the rotor blade is stationary.

[0021] Simultaneously with the rotor blade bearing test, the rotor blade itself can be tested using the blade actuators, employing all test modes known from the prior art. The rotor blade is set into vibration, with deflections in the pivot and / or flapping direction being possible. In particular, uniaxial or biaxial tests can be performed. The blade actuators can, for example, comprise one or more actuators and / or one or more load cylinders and / or one or more cables and / or one or more vibrating masses. These can each act on one or more load frames, which can be arranged on the rotor blade.

[0022] The proposed test rig allows for the execution of both tests (rotor blade test / rotor blade bearing test), particularly those known from the prior art. The proposed design enables the mechanical decoupling of the rotor blade test from the rotor blade bearing test. This allows for the consideration of different objectives and material-specific differences between the components during the test design and configuration. For example, the modal properties of the rigidly clamped rotor blade are used to test the rotor blades, aiming to achieve high energy efficiency by exciting the bending natural frequencies. To this end, the rotor blade is subjected to continuous bending vibration, for instance, by applying dynamic loads close to its natural frequencies along its principal axes, enabling a high number of load cycles to be performed within a reasonable timeframe.The swivel amplitude and the speed of the oscillating movement are determined based on the cyclic load of the rotor blade bearing raceway systems expected during operation of the wind turbine, as well as the operating conditions.

[0023] Since the rotational degrees of freedom of the two components under test are decoupled, both tests can be designed individually without negatively affecting each other. At the same time, the two components are tested as a system, with the actual connection conditions between them. It is also noteworthy that, for example, the rotor blade test can have a beneficial effect on the blade bearing test, especially if performed simultaneously, as relevant stiffnesses of the real system consisting of the rotor blade and rotor blade bearing are taken into account.

[0024] The loads generated during the rotor blade test can be used to realistically subject the rotor blade bearing to dynamic bending moments. For example, to test the fatigue life of the raceway system and the rotor blade bearing structure, an oscillating rotational movement of one of the rotor blade bearing rings is set by the first rotational actuator simultaneously with the rotor blade test.

[0025] Decoupling the two tests prevents negative impacts: For example, the rotor blade test does not need to be aborted due to a premature rotor blade bearing failure. Instead, the rotor blade test can continue. In this case, the rotor blade bearing continues to be loaded via the rotor blade, but no further rotational movement of the rotor blade bearing is performed to prevent further damage. Conversely, it is also conceivable to continue the rotor blade bearing test if the rotor blade has failed.

[0026] Besides applying the most realistic load possible to the rotor blade bearing, accelerating the test run is a key focus. The total test duration can be predetermined by the design of the rotor blade test, or it can be determined by the design of the rotor blade bearing test. Since the fatigue behavior of the rotor blade bearing and rotor blade can differ significantly, particularly due to the different materials used, it may be advisable to divide the rotor blade bearing test into two consecutive trials. The first trial involves simultaneous dynamic loading of the rotor blade, while the second, and especially subsequent, trial involves only static loading of the rotor blade. In this second trial, a static load is transferred to the rotor blade bearing via the rotor blade, while the rotational movement of the rotor blade bearing is executed using the first rotational actuator.

[0027] In the bearing tests, it is advantageous that the rotor blade is used as a real connecting component and does not need to be simulated.

[0028] The pitch-lock mechanism can act directly or indirectly on the rotor blade. That is, it can be connected, for example, to the rotor blade itself or to a bearing ring of the rotor blade bearing on the blade side.

[0029] The pitch-lock mechanism can be designed as a fixed coupling that fixes the pitch of the rotor blade relative to the base. In particular, it can be a torsionally rigid and / or flexible coupling. Within the scope of the method, the pitch of the rotor blade can be permanently fixed using the fixed coupling as a pitch-lock mechanism. The fixed coupling can, for example, be connected to the base, or alternatively or additionally to the floor, a wall, and / or another stationary test rig component. It can comprise one or more rods. It can, for example, engage the rotor blade-side bearing ring of the rotor blade bearing and / or the rotor blade itself. This type of pitch mechanism allows for the creation of a completely fixed rotor blade ("true pitch-lock"), whose desired pitch is typicallyBefore the rotor blade and rotor blade bearing tests begin, the fixed coupling is attached and then held in place. This pitch lock also allows for a particularly secure fixation of the rotor blade, which can make it possible to continue the rotor blade test even if the rotor blade bearing fatigues prematurely.

[0030] The pitch-lock mechanism can also include a second rotary actuator designed to counteract the first rotary actuator in order to fix the rotor blade pitch. This second rotary actuator can, for example, act on a blade-side bearing ring of the rotor blade bearing. In other words, the pitch-lock mechanism can be designed as an additional drive that compensates for the bearing rotation provided by the first rotary actuator by effectively acting downstream of the first rotary actuator, for example, on the blade-side bearing ring of the rotor blade bearing, or even on the rotor blade itself. The second rotary actuator can be controlled or regulated in a coordinated manner with the first rotary actuator to maintain a fixed pitch for the rotor blade when required during rotor blade testing. A control and / or regulation device can be provided for this purpose.Unlike the "true pitch lock" described above, the pitch-lock mechanism with a second rotary actuator also allows for adjustment of the rotor blade pitch during testing, thus enabling even more versatile tests ("pseudo-pitch lock"). In coordination with the movement of the first rotary actuator, the second actuator can be controlled or regulated so that the rotor blade is not permanently fixed, but rather rotated relative to the base for pitch adjustment, preferably without interrupting the movement of the first actuator. Within this method, the rotor blade pitch can therefore be set using the second rotary actuator as a pitch-lock mechanism, by the second actuator acting in opposition to the first, whereby the pitch can be permanently fixed or changed or adjusted as needed.

[0031] An adapter can be arranged between the test stand bearing and the rotor blade bearing. The adapter can, for example, have at least one continuous, one-piece adapter ring. This allows for particularly high stiffness. A multi-part adapter is also possible. Preferably, the adapter (or the adapter components of a multi-part adapter combined) emulates the stiffness of a wind turbine hub. A continuous, one-piece ring, in particular, prevents the adapter from buckling or bending.

[0032] The pitch-lock mechanism, both in the form of a true pitch-lock and a pseudo-pitch-lock, can be equipped with a measuring device for recording the torque. This can, in particular, make it possible to record and monitor the frictional torque of the test bench bearing.

[0033] The test rig bearing can, for example, feature oil circulation lubrication. This allows for a longer service life for the test rig bearing. In particular, it can be achieved that the test rig bearing has a longer service life than the tested rotor blade bearings, making the test rig bearings suitable for multiple uses.

[0034] The system can include a temperature control device that allows for temperature adjustment. For example, it can include an enclosure, particularly a flexible enclosure, for the rotor blade bearing, so that the temperature of the rotor blade bearing can be adjusted during testing. In particular, temperature settings covering the range of -20°C to +60°C are possible. Preferably, temperatures between both -10°C and -20°C and between +50°C and +60°C are adjustable.

[0035] It is understood that the features described here in connection with the system can also be claimed for the method, and vice versa. The invention is explained in more detail below with reference to the accompanying figures. These show:

[0036] Fig. 1 a system for combined testing of a rotor blade of a wind turbine and a rotor blade bearing of a wind turbine;

[0037] Fig. 2a shows a section of the system, with a pitch mechanism that includes a torsionally rigid coupling; and

[0038] Fig. 2b shows a section of the system, with a pitch mechanism that includes a rotary actuator.

[0039] Figure 1 shows a system for the combined testing of a rotor blade 2 of a wind turbine and a rotor blade bearing 3 of a wind turbine. A test stand base 1 is visible on the left side of the image, to which a test stand bearing 4 is attached. A base-side bearing ring 4a of the test stand bearing is connected to the base 1. In this example, this is the inner ring, although it is equally possible to design the base-side bearing ring 4a as the outer ring. The test stand bearing 4 is designed to accommodate the rotor blade bearing 3 together with the rotor blade 2 attached to it, so that one degree of rotational freedom is provided for the rotor blade bearing 3 by means of the test stand bearing 4. For this purpose, an adapter 6 is attached to a rotor blade bearing-side bearing ring 4b of the test stand bearing 4, which enables a connection between the rotor blade bearing-side bearing ring 4b of the test stand bearing 4 and the hub-side bearing ring 3a of the rotor blade bearing 3.The adapter 6 comprises a continuous, one-piece adapter ring, the continuous one-piece design of which helps to prevent deformation or buckling and to provide a connection stiffness comparable to the actual connection stiffness at the hub of a wind turbine. A rotor blade-side bearing ring 3b of the rotor blade bearing 3 under test is connected to the rotor blade 2 under test. This means that the connections at this interface are exactly those that are also provided in the actual operation of the wind turbine. This creates a particularly realistic test environment. The system further includes a pitch-lock mechanism 7, which provides and maintains a defined pitch of the rotor blade 2 relative to the test stand base 1 during testing. Reference is made to Figures 2a and 2b and the explanations below.The pitch-lock mechanism 7 ensures that the pitch of the rotor blade 2 can be fixed during testing, while maintaining the rotational freedom of the rotor blade bearing 3 under test. The rotor blade bearing-side bearing ring 4b of the test stand bearing 4, the adapter 6, and the hub-side bearing ring 3b of the rotor blade bearing 3 form a unit that is rotationally decoupled from the other components – in particular, from the test stand base 1 and the rotor blade 2. A first rotary actuator 5 engages this unit and imparts a rotational movement to it in order to test the rotor blade bearing 3. In this example, the first rotary actuator 5 engages the rotor blade bearing-side bearing ring 4b of the test stand bearing. This has the advantage that the actuator 5 does not need to be changed when the test specimen is changed. However, it is also conceivable that the actuator 5 engages the hub-side bearing ring 3a of the rotor blade bearing 3.The first rotary actuator 5 can be, for example, electrically or hydraulically designed. Using the first rotary actuator 5, cyclic back-and-forth rotations are initiated, for example, by means of the rotationally decoupled unit, in order to load the rotor blade bearing 3, in particular in the contact area between the hub-side bearing ring 3a and the rotor blade-side bearing ring 3b.

[0040] In addition to the first rotary actuator 5, a blade actuator 9 is also provided, which deflects the rotor blade 2 for testing purposes. For this purpose, a load frame, visible in the figure, is arranged on the rotor blade 2, to which the blade actuator attaches. More than one load frame can also be provided. In principle, all methods known from the prior art for introducing loads into the load frame can be used within the scope of the present invention. As indicated by the arrows, forces in the direction of the stroke (F) can be applied. x) and / or in the direction of rotation (F y ) be provided for, within the framework of uniaxial or biaxial tests, whereby harmonic cyclic vibrations are usually generated.

[0041] In the invention, the testing of the rotor blade bearing 3 by applying a rotational movement can be carried out simultaneously with the testing of the rotor blade 2 by applying vibrations to the rotor blade 2. The pitch-lock mechanism 7 provides and maintains the set pitch of the rotor blade 2. It is advantageously utilized that the deflection of the rotor blade 2 at the rotor blade bearing 3 causes additional loads, which are added to the loads caused by the rotational movement and contribute to the test.

[0042] Simultaneous testing can continue, for example, until one of the two components becomes fatigued or the test is completed. If, for instance, rotor blade bearing 3 fails, the rotational movement can be stopped to avoid further stressing the bearing, while the pivoting of the rotor blade can continue until this test is also completed.

[0043] One embodiment of a method for the combined testing of the two components provides that in a first test the rotor blade bearing 3 is tested by subjecting the rotor blade bearing 3 to rotational motion under simultaneous dynamic loading of the rotor blade 2, wherein in a second, subsequent test the rotor blade bearing 3 is tested by subjecting the rotor blade bearing 3 to rotational motion while simultaneously subjecting the rotor blade 2 to purely static loading.

[0044] The system can be equipped with a measuring device for recording the torque, both the pitch-lock mechanism 7 and the rotation actuator 5.

[0045] The test stand bearing 4 can have an oil circulation lubrication system to create a longer service life for the test stand bearing, which in particular exceeds the expected service life of the rotor blade bearings to be tested, thus enabling the reuse of the test stand bearing 4 in several successive tests.

[0046] An optional tilting arrangement 8 is arranged at the base, which makes it possible to tilt the base in such a way that the rotor blade gains a greater distance from the ground in order to allow greater deflections.

[0047] Fig. 2a shows a section of the system from Fig. 1. The pitch-lock mechanism 7 is designed as a torsionally rigid and flexibly flexible coupling that mechanically fixes the pitch of the rotor blade 2 relative to the base 1, forming a "true pitch lock". A fixed rod is provided for this purpose, which directly couples the test stand base 1 to the rotor blade 2 under test. Several rods can also be used. Alternatively or in addition to the connection between the base 1 and the rotor blade 2, the rotor blade 2 can also be connected to another fixed unit, such as the floor or a wall, etc.

[0048] In this procedure, the pitch of rotor blade 2 is set once before the test begins and fixed with the rod. Rotations, i.e., pitch changes of rotor blade 2 during the test, are generally not permitted. The rod may include a measuring device for recording the torque.

[0049] Fig. 2b shows a modification of the system from Figure 1, in which the pitch-lock mechanism 7' includes a second rotary actuator. This actuator is configured to counteract the first rotary actuator 5 in order to fix the pitch of the rotor blade 2. From the perspective of the base 1, the second rotary actuator effectively engages the rotor blade-side bearing ring 3b of the rotor blade bearing 3 behind the rotationally decoupled unit to which the first rotary actuator 5 engages. It can be operated in the exact opposite direction to the first rotary actuator, so that the rotor blade-side bearing ring 3b and the rotor blade 2 mounted on it remain completely stationary, just as in the case of Figure 2a.

[0050] Unlike in the case of Figure 2a, the pitch of rotor blade 2 is not mechanically fixed torsionally rigidly. Instead, the second rotary actuator is controlled and regulated in such a way that the pitch of rotor blade 2 remains constant as long as this is desired within the scope of the process. The neologism "pseudo-pitch-lock" is used here for this purpose. A control device 10 can be provided for this purpose, which is connected to the first rotary actuator 5 and the second rotary actuator of the pitch-lock mechanism 7'. This device registers, for example, the torques and deflections detected there and controls both mechanisms in a coordinated manner. Additional sensors can be provided, which, for example, monitor the position of rotor blade 2. The second rotary actuator also allows a change in pitch if this is desired during testing.

[0051] Reference symbol list

[0052] 1 test bench basis

[0053] 2 rotor blades

[0054] 3 rotor blade bearings

[0055] 3a hub-side bearing ring

[0056] 3b rotor blade-side bearing ring

[0057] 4 test bench bearings

[0058] 4a base-side bearing ring

[0059] 4b rotor blade bearing side bearing ring

[0060] 5 Rotary actuators

[0061] 6 adapters

[0062] 7.7' Pitch-Lock mechanism

[0063] 8 Tilting arrangement

[0064] 9 Leaf Actuators

[0065] 10 Control and regulating device

Claims

Patent claims 1. System for the combined testing of a rotor blade (2) of a wind turbine and a rotor blade bearing (3) of a wind turbine, comprising: a test stand base (1) with a test stand bearing (4) arranged on the test stand base (1), wherein the test stand bearing (4) is configured to receive the rotor blade bearing (3) with the rotor blade (2) arranged thereon, such that a degree of rotational freedom is provided for the rotor blade bearing (3) by means of the test stand bearing (4); a pitch-lock mechanism (7, 7') for providing a defined pitch of the rotor blade (2) relative to the test stand base (1); a first rotational actuator (5) for applying a rotational movement to the rotor blade bearing (3) for testing the rotor blade bearing (3); a blade actuator (9) for deflecting the rotor blade (2) for testing the rotor blade (2).

2. System according to claim 1, wherein the first rotary actuator (5) engages a bearing ring of the test stand bearing (4).

3. System according to claim 1 or 2, wherein the pitch-lock mechanism (7) is designed as a fixed coupling, in particular a torsionally rigid and / or flexible coupling, which fixes the pitch of the rotor blade (2) relative to the test stand base (1).

4. System according to claim 1 or 2, wherein the pitch-lock mechanism (7') comprises a second rotary actuator configured to counteract the first rotary actuator (5) in order to fix the pitch of the rotor blade (2).

5. System according to claim 4, wherein the second rotary actuator engages a rotor blade-side bearing ring (3b) of the rotor blade bearing (3).

6. System according to one of the preceding claims, wherein an adapter (6) is arranged between the test stand bearing (4) and the rotor blade bearing (3).

7. System according to claim 6, wherein the adapter (6) has a circumferential one-piece adapter ring.

8. System according to one of the preceding claims, wherein the pitch-lock mechanism (7, 7') and / or the rotary actuator (5) are equipped with a measuring device for detecting the torque.

9. System according to one of the preceding claims, wherein the test stand bearing (4) has an oil circulation lubrication system.

10. Method for combined testing of a rotor blade (2) of a wind turbine and a rotor blade bearing (3) of a wind turbine, comprising: Providing a test bench base (1) with a test bench base (1) arranged test stand bearing (4); Attaching the rotor blade bearing (3) with the rotor blade (2) arranged thereon to the test stand bearing (4) so ​​that one degree of rotational freedom is provided for the rotor blade bearing (3) by means of the test stand bearing (4); Testing the rotor blade bearing (3) by subjecting the rotor blade bearing (3) to a rotational movement using a first rotational actuator (5); Testing the rotor blade (2) by impacting the rotor blade (2) with vibrations by means of a blade actuator (9); wherein a fixed pitch of the rotor blade (2) relative to the test stand base is provided by means of a pitch-lock mechanism (7, 7').

11. Method according to claim 10, wherein the pitch of the rotor blade (2) is fixed by means of a fixed coupling as a pitch-lock mechanism (7, 7').

12. Method according to claim 10, wherein the pitch of the rotor blade (2) is fixed by means of a second rotary actuator as a pitch-lock mechanism, in that the second rotary actuator opposes the first rotary actuator (5).

13. Method according to one of claims 10 to 12, wherein the testing of the rotor blade bearing (3) and the testing of the rotor blade (2) are performed at least partially simultaneously.

14. Method according to one of claims 10 to 13, wherein in a first test the rotor blade bearing (3) is tested by subjecting the rotor blade bearing (3) to rotational motion under simultaneous dynamic loading of the rotor blade (2), and in a second test the rotor blade bearing (3) is tested by subjecting the rotor blade bearing (3) to rotational motion under simultaneous static loading of the rotor blade (2).

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