KR20130086130A - Rotor blade pitch adjustment device - Google Patents

Abstract

The present invention relates to a rotor blade pitch adjusting device of a wind power plant, comprising: a rotor blade pitch adjusting device including a motor / pump unit having a variable rotational speed and direction and connected to fluid communication with a hydraulic actuator through a hydraulic control / adjustment system. It is about. The actuator is mechanically coupled for the rotation of the rotor blade about the longitudinal axis of the rotor blade and at least one rotor blade of the wind power plant. According to the present invention there is provided an electrical control circuit comprising an emergency energy supply for operation of a motor.

Description

ROTOR BLADE PITCH ADJUSTMENT DEVICE}

The present invention relates to a rotor blade pitch adjusting device of a wind power plant according to the preamble of claim 1.

The wind power plant is rotated by the lift of the wind against the rotor blades, and the wind power increases to three squares of the wind speed. That is, in modern wind power plants, the rotor output (generated by lift) is usually greater than the rated power at wind speeds of about 9 m / s, so that the output power of the wind power plant is particularly important to prevent material damage of sensitive rotor blades. Should be limited.

There are two main concepts of power limitation in the prior art.

One possibility is to limit output delivery by intentional stall in the rotor blades when a certain wind speed is exceeded. The so-called stall adjustment is the simplest and oldest adjustment system and turbulence is generated on the rotor blades at certain wind speeds (at constant rotational speeds) that can be detected by analysis, so the lift is automatically reduced and accordingly the power output of the plant It is based on forming the rotor blade profile (ie its curvature) so that it can be maintained at its rated output. However, a problem with this control scheme is that the rotor blade profile does not remain the same and changes over time due to the influence of the climate, ie rain, ice / snow, wear and the like. Therefore, stall-wind speed cannot be accurately determined in advance, and the design of the rotor blade profile is difficult. For this reason, the stall limit is set such that the rated power is not achieved to create a safety margin, which results in poor power output and efficiency of the power plant.

Another possibility of power limitation relates to the (active) rotation of the rotor blades (pitch), whereby the adjustment of the output in the wind power plant being pitch controlled is ensured by the rotation of the rotor blades using a so-called pitch system. In this case, the following hydrodynamic relationships are used:

In the normal operating range of a wind power plant, the output coefficient of the rotor blades increases with the angle of attack (see aerofoil wing of the plane). That is, a low angle of attack provides less lift and thus less power. By this principle, the output is adapted to the wind speed by the rotation (pitch) of the rotor blades.

At very weak winds (0-4 m / s), conventional wind power plants do not produce electricity because the wind flow rate is too low to create sufficient lift in the rotor blades. In this case, the rotor blades are rotated to the so-called vane position (pitch angle = 90 °; angle of attack = 0 °), and no lift occurs at that position.

At low winds (4-13 m / s), wind power plants spin and produce useful output. However, the wind is too weak to reach the rated power of the power plant. In this case, the pitch angle is minimum (pitch angle = 0 °), so the angle of attack is maximum so that as much wind energy as possible is converted into mechanical energy.

-In strong winds (13-25 m / s) the rated power output of a power plant may be exceeded. To prevent this, the power plant is "pitch regulated". That is, the rotor blades are rotated continuously or stepwise again in the direction of the vane position.

-In case of storms (from 25 m / s) the risk of damage is so great that the rotor blades are basically rotated to the vane position for safety.

In conventional wind rotors, which generally include three rotor blades, it has already been shown that only one rotor blade pitch is sufficient to adapt the power plant to varying wind speeds. This mode of operation according to the above description also applies to the object of the present invention.

Such a pitch system is known, for example, from the prior art according to WO 2009/064 264. The pitch system includes an electro-hydraulic actuator for controlling / adjusting the rotational position of the rotor blades of the wind power plant. The actuator includes an electric motor that is variable in rotational speed and direction depending on the current strength and polarity, which drives a hydraulic pump that is the primary pressure medium source through the motor shaft. The pump delivers hydraulic fluid through a hydraulic circuit to a hydraulic motor, for example in the form of a regulating cylinder, which is disposed inside the rotor hub (along with the pump and the electric motor) and is positioned around the rotor blade and its longitudinal axis. It is operatively connected for rotation. Another, secondary pressure medium source in the form of a pressure accumulator is incorporated within the hydraulic circuit, which secondary pressure medium source provides pressure in the event of failure of the primary pressure medium source to the hydraulic circuit to provide hydraulic circuits in the category of emergency operation. The electron blade is rotated in accordance with the above definition to the (sure) vane position.

EP 1 739 807 A2 also discloses an electric actuator for rotating at least one rotor blade of a wind power plant comprising an emergency energy supply connected to the electric circuit of the actuator. The emergency energy supply includes an energy accumulator that provides a support voltage, the support voltage being less than 80% of the rated operating voltage of the electrical circuit and can be connected when the circuit voltage falls below the support voltage.

It is an object of the present invention to provide a rotor blade pitch adjusting device of a wind power plant that enables simple kinematics while properly utilizing the advantages of electric and hydraulic blade pitch adjusting systems.

The object is achieved by a rotor blade pitch adjusting device of a wind power plant comprising the features of claim 1. Preferred embodiments of the invention are subject of the dependent claims.

In order to solve the above problem, as a rotor blade pitch adjusting device of a wind power plant, the variable speed and preferably the rotational speed variable motor / pump unit, the motor / pump unit is a hydraulic actuator through a hydraulic control / regulation system And fluidly connected, the actuator is mechanically coupled for its rotation about its longitudinal axis with at least one rotor blade of the wind power plant. According to an aspect of the invention, the electrical control circuit of the motor / pump unit comprises an emergency energy supply, which supplies at least an electrical energy to the control circuit in the event of a failure of the external electricity supply network. In this way, all the functions of the hydraulic control system, including the electromagnetically actuated valve, can be maintained at least for emergency operation. Thus, the hydraulic control system does not necessarily need to be designed for emergency operation (without current).

The emergency energy supply is preferably formed as an accumulator or capacitor which can be connected to the control circuit at a predetermined voltage drop in the electrical control circuit. These accumulators have a very long life and have a high energy density sufficient for emergency operation even at small dimensions.

According to another aspect, an emergency energy supply for supplying energy to the electrical control circuit and the motor / pump unit can be connected. If the energy supply to the motor is interrupted, the energy supply can be maintained through the emergency energy supply at least for emergency operation.

Another aspect of the invention relates to a hydraulic control / regulation system, wherein the control / regulation system comprises a hydraulic emergency actuating device for supplying hydraulic energy to the hydraulic actuator in the event of a failure or reduction of the motor / pump unit according to the invention. do. In other words, if the electric drive motor of the hydraulic pump fails, the electric emergency energy supply will not work. In this case, auxiliary hydraulic pressure for at least emergency operation (to rotate at least one rotor blade to the vane position) can be ensured. This dual protection measure is an important advantage over the prior art. Full electrical protection measures are ineffective as described above, for example, when the electric motor, which is the last member of the electric control chain, malfunctions. The hydraulic accumulator acts directly on the hydraulic actuator and thus on the last member of the hydraulic control chain. On the other hand, the pressure accumulator may lose the charging pressure over time. Thus, the combination of the two safety systems provides maximum protection in the event of a plant malfunction.

Finally, in accordance with another aspect of the invention the rotor blade pitch adjusting device comprises a directional variable and preferably rotational speed variable motor / pump unit, said motor / pump unit being connected to a hydraulic actuator via a hydraulic control / adjustment system. The fluid is connected through. The actuator is mechanically connected with at least one rotor blade for pitch adjustment. In this case, the actuator is formed as a pressure cylinder in a multichamber configuration (preferably three pressure chamber). One pressure chamber is in fluid communication with the pressure accumulator solely for emergency operation, while the other pressure chambers can be supplied with hydraulic fluid solely for normal regulation / control operation of the pressure pump. This allows the emergency operating pressure chamber to be adjusted in relation to the accumulator pressure and accumulator capacity of the pressure accumulator, thereby optimizing the emergency operating system without the need for the remaining hydraulic system to be adjusted accordingly. The aspect mentioned at the end of the present invention may be claimed separately from the other aspects, as it may be practiced in the rotor blade pitch adjusting device irrespective of the foregoing or in combination with the foregoing.

According to the present invention, there is provided a rotor blade pitch adjusting device of a wind power plant that enables simple kinematics while properly utilizing the advantages of electric and hydraulic blade pitch adjusting systems.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram relating to a rotor blade pitch adjusting device of a wind power plant to show the possibility of combining individual parts of an electric and hydraulic drive.
Figure 2 is a rotor blade pitch adjusting device of a wind power plant according to the first preferred embodiment of the present invention.
3 is a rotor blade pitch adjusting device of a wind power plant according to a second preferred embodiment of the present invention.
Figure 4 is a rotor blade pitch adjusting device of a wind power plant according to a third preferred embodiment of the present invention.

1 schematically shows a rotor blade pitch adjusting device of a wind power plant according to the invention comprising a hydraulic system 1 consisting of a preferably directional and preferably variable speed motor / pump unit 2. The motor / pump unit 2 is connected in fluid communication with the hydraulic actuator 6 via a hydraulic control / regulation system 4. The actuator 6 is mechanically coupled with at least one rotor blade (not shown) of the wind power plant to rotate the rotor blade about its longitudinal axis. An electrical control circuit 12 is provided which comprises an emergency energy supply device 10 according to the invention for the operation of the motor 8. As an alternative or supplement to this, the hydraulic system 1 can be provided with an emergency actuating device (emergency accumulator) 14. Thus, the rotor blade pitch adjustment device according to the invention comprises at least one, preferably two safety systems, in which at least one rotor blade of the wind power plant in the event of a disturbance by said safety system is the category of emergency operation. Can be rotated to the vane position.

On the one hand, an electric emergency accumulator 10 is provided, which accumulates an electric drive device (electric control circuit 12 together with an electric servo drive, and optionally a motor 8, in the event of a failure of the primary electric supply network). Electrical energy, which is at least sufficient for emergency operation in accordance with the above definition.

On the other hand, a hydraulic emergency accumulator 14 may optionally be provided in addition to the hydraulic system 1 (pump 16 together forming a hydraulic transmission, hydraulic pressure control / control system 4, actuator 6). The hydraulic emergency accumulator supplies hydraulic energy to the hydraulic system 1 in the form of hydraulic fluid flow, for example. The hydraulic emergency accumulator 14 is important if, for example, the motor 8 at the end of the electric drive chain fails and the electrical emergency supply becomes ineffective.

2 shows a first embodiment of the invention, in which the above-described basic principles are technically embodied.

An unshown rotor blade of a wind power plant is rotated about its longitudinal axis by a double rod cylinder 6, which is coupled with the rotor blade via a lever mechanism not shown. For operation of the cylinder 6, a pressure pump 16 is provided which is connected in parallel with the cylinder 6, ie, two connections are connected to the respective pressure chambers 6A, 6B of the cylinder 6. The pressure pump 16 can deliver hydraulic fluid in two directions, which are recirculated in the pressure chambers 6A, 6B of the cylinder.

A shuttle valve 18 (inverted) in parallel to the pressure pump 16 is connected in the pressure pump bypass line 20, and the compensation chamber 22 re-guides (returns) the hydraulic fluid through the shuttle valve 18. To the bypass line 20 for suction).

In addition, a secondary pressure medium source is provided, for example in the form of a pressure accumulator 14, in one of the pressure chambers 6B of the cylinder 6, which must be pressurized for the rotation of the rotor blades to the vane position of the rotor blades. The pressure medium source can be connected in fluid communication with the pressure chamber 6B via a control valve 24, preferably an electromagnetically controlled (opened) 2/2 directional valve. The pressure chamber 6A opposite the pressure chamber 6B has an additional inlet 26 towards the compensation vessel / tank 22. A control valve 28, preferably a 2/2 directional valve to be opened electromagnetically, is connected in the inlet 26, the valve being pre-stressed with a spring in the closed position.

The pressure pump 16 is driven by an electric motor 8, which is controlled / adjusted by an electric circuit (driver circuit), not shown again, so that the rotational direction and preferably the rotational speed of the motor 8 is Can be varied. The electrical circuit comprises an emergency energy supply in the form of an accumulator, said emergency energy supply comprising an emergency current for a specific (limited) time to the electric circuit and optionally the electric motor 8 or during a specific maximum operation of the cylinder 6. Can be provided.

The manner of operation of the rotor blade pitch adjustment device shown in FIG. 1 is described below:

Current is supplied to all said directional valves during normal (faultless) operation, such that the directional valve 24 between the pressure accumulator 14 and the pressure chamber 6B and the directional valve between the tank 22 and the pressure chamber 6A. 28 is in the blocking position. In this case, the pressure pump 16 is operated such that the at least one rotor blade has a specific pitch angle depending on the strength of the wind via the electric motor 8 which is variable in rotational speed and direction of rotation, at which rotor output It does not exceed the rated power of this plant. As an alternative to the variable speed electric motor 8, the pressure pump 16 may be implemented with a variable displacement. In order to fill the pressure accumulator 14, fluid must be withdrawn from the hydraulic circuit. For this purpose, the shuttle valve 18 is connected in fluid communication with the tank 22 via an external suction line, as described above, so that the pressure pump 16 transfers fluid from the tank into the pressure accumulator 14. The pressure accumulator may be re-sent until it has a specific pressure.

On occurrence of a failure, i.e. when the regular voltage / current supply of the electrical circuit is interrupted and / or when the delivery capacity of the pump 16 is reduced and / or the hydraulic pressure in the hydraulic regulation / control system 4 is reduced below a predetermined value, respectively. At the same time, an emergency operation is triggered so that the rotor blade pitch adjusting device is activated for emergency operation to adjust the rotor blade to the vane position.

In this case, the electric emergency energy supply device supplies energy to the electric circuit, and the electric control circuit 12 applies the hydraulic circuit 4 and the pressure for the rotation of the rotor blade to the position where the cylinder 6 is cut. To be supplied, controlled. If the electric motor 8 fails, that is to say that the connection of the electric emergency energy supply does not work, the hydraulic emergency actuating device is activated. In this case, the supply of current for all directional valves 24, 28 is interrupted, whereby the valves are connected to the open position by corresponding spring prestresses. The pressure accumulator 14 is thus not connected to the hydraulic control system 4 via a pre-connected directional valve 24, but the corresponding operating pressure in the cylinder 6 is increased for rotation of the rotor blades to the vane position. do. Since the pump 16 is stopped, hydraulic fluid does not leak from the chamber 6A through the pump 16. However, since chamber 6A directly accesses tank 22 via directional valve 28 in this (emergency), hydraulic fluid is pressurized from chamber 6A into tank 22 during emergency operation of the cylinder.

Figure 3 shows a second preferred embodiment of the invention, which in principle corresponds to the first embodiment, but omits the arrangement of the hydraulic emergency device. In this case, only an electric emergency energy supply device is provided for supplying electric current to the electric motor 8 for the operation of the hydraulic transmission. Since the second embodiment is not provided with a pressure accumulator causing the (pumpless) operation of the actuator 6, as described in the first embodiment, the pressure chamber 6A and the tank 22 of the actuator 6 are provided. There is no need for an external inlet with a 2 / 2-way valve connected in between.

Finally, a third embodiment of the present invention is described with reference to FIG. The third embodiment corresponds in principle to the first embodiment of the invention, but in the third embodiment a multi-chamber cylinder 6, preferably a three-chamber cylinder, is used for the rotation of at least one rotor blade.

In this case, the pressure accumulator 14 is connected to a single chamber 6B via an electromagnetically open directional valve 24 for emergency operation, which in this case rotates the rotor blade to the vane position during the emergency operation. Only pressurized to make it work. For this purpose (emergency operation) a pressure relief or inlet line 26 is connected to the pressure chamber 6B, which line 26 extends directly into the tank 22 and is electromagnetically in the line 26. An open 2 / 2-way valve 28 is connected. Since the directional valve 28 is in the open position under current during normal operation, the piston displaces or re-absorbs the hydraulic fluid from the pressure chamber 6B through the inlet line 26 during the axial movement (emergency operation). can do.

The two pressure chambers 6A, 6C of the multichamber cylinder, opposite the pressure chamber 6B, are connected to the two connections of the pump 16, so that the cylinder piston is in the delivery direction of the pump 16 in normal operation. Can reciprocate. The two chambers 6A and 6C are directly connected to each other via a shorting line, to which a 2 / 2-way valve 30 is opened which is electromagnetically opened in the shorting line. Finally, a pressure pump bypass line 20 is disposed towards the pump 16, within which the (reversed) shuttle valve 18 is connected, which shuttle fluid is in fluid communication with the tank 22. Is connected.

The mode of operation of the third preferred embodiment is described below:

As described above, the pump 16 is in fluid communication with the chambers 6A and 6C to move the cylinder piston during normal operation. In normal operation the current is supplied to the directional valves 24, 28 and 30. Thus, valve 28 is opened and valves 24 and 30 are closed. That is, the pressure accumulator 14 is separated from the chamber 6B, and a connection between the tank 22 and the chamber 6B is given through the line 26, while the chambers 6A and 6C are separated from each other. Thus, during normal operation of the piston, the corresponding fluid volume between the two chambers 6A and 6C is repumped and exchanged between the chamber 6B and the tank 22 at the same time.

In the event of an emergency (eg in case of a current interruption-no current is supplied to the valve), the accumulator 14 is connected to the chamber 6B, while the chambers 6A and 6C are shorted to each other via the valve 30. The pressure acting on the chamber 6B by the accumulator pressure forces the piston according to FIG. 4 to the left (to the vane position). In this case, the oil volume is displaced from the chamber 6A to the chamber 6C. The differential capacity generated by the possible face ratio is compensated for by the shuttle valve 18.

The advantage of such a multichamber cylinder is that the dynamic, energy and assembly space advantages are manifested by the proper selection of the face ratio, the connection of the cylinder chambers, and the position of the accumulator on the piston face.

1 hydraulic system
2 motor / pump unit
4 hydraulic control system
6 actuator / cylinder
6A, 6B, 6C Cylinder Chambers
8 electric motor
10 emergency energy supply
12 electrical control circuit
14 Emergency Actuator / Pressure Accumulator
16 pump
18 shuttle valve
20 pressure pump bypass line
22 tank
24 Control valve between pressure accumulator and cylinder
26 inlet (line)
28 2/2 directional valve
Control valve for 30 pressure chamber (6C)

Claims (9)

Rotor blade pitch adjusting device of a wind power plant, comprising a directional variable motor / pump unit (2), said motor / pump unit being in fluid communication with the hydraulic actuator (6) via a hydraulic control / regulation system (4). Wherein the actuator is mechanically coupled for rotation of the rotor blade about the longitudinal axis of the rotor blade and at least one rotor blade of a wind power plant.
Rotor blade pitch control device, characterized in that the electric control circuit (12) of the motor / pump unit (2) comprises an emergency energy supply (10). 2. The rotor blade pitch adjustment of claim 1 wherein the emergency energy supply device 10 is an accumulator or a capacitor that can be connected to the electrical control circuit at a predetermined voltage drop in the electrical control circuit 12. Device. 3. Rotor blade pitch adjustment device according to claim 2, characterized in that the emergency energy supply (10) is provided for supplying energy to the electrical control circuit (12) and the motor / pump unit (2). The hydraulic emergency actuating device (14) according to claim 1 or 2, characterized in that a hydraulic emergency actuating device (14) is provided for supplying hydraulic energy to the hydraulic actuator (6) upon failure or reduction of output of the motor / pump unit (2). Rotor blade pitch adjustment device. 5. Rotor blade pitch adjustment device according to any of the preceding claims, characterized in that the hydraulic actuator (6) is a hydraulic piston cylinder unit. 6. The rotor blade pitch adjusting device according to claim 1, wherein the motor / pump unit is controllable in rotational speed by an electrical control circuit. 7. The rotor blade pitch adjusting device according to any one of claims 1 to 6, wherein the hydraulic piston cylinder unit is preferably a multi-chamber cylinder of a three-chamber configuration. 8. An emergency operating device (14), preferably from the pressure accumulator (14), according to claim 7, to rotate at least one rotor blade to its vane position in emergency operation only in one of the chambers (6B). While hydraulic fluid can be supplied, at least two other chambers 6A, 6C can be supplied with hydraulic fluid to rotate at least one rotor blade from and to its vane position during normal operation. Rotor blade pitch adjustment device, characterized in that. 9. The hydraulic emergency actuating device (14) according to claim 8, characterized in that the hydraulic emergency actuating device (14) is connected to only one chamber (6B) via a control valve, preferably an electromagnetically open 2/2 directional valve (24). Rotor blade pitch adjustment device.

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