WO2019134972A1 - Redundant hydraulic pitch control - Google Patents

Redundant hydraulic pitch control Download PDF

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Publication number
WO2019134972A1
WO2019134972A1 PCT/EP2019/050169 EP2019050169W WO2019134972A1 WO 2019134972 A1 WO2019134972 A1 WO 2019134972A1 EP 2019050169 W EP2019050169 W EP 2019050169W WO 2019134972 A1 WO2019134972 A1 WO 2019134972A1
Authority
WO
WIPO (PCT)
Prior art keywords
accumulator
hydraulic
accumulator bank
bank
pressure
Prior art date
Application number
PCT/EP2019/050169
Other languages
French (fr)
Inventor
Jonathan SHEIDER
Tommy Hastrup KNUDSEN
Original Assignee
Siemens Gamesa Renewable Energy A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Gamesa Renewable Energy A/S filed Critical Siemens Gamesa Renewable Energy A/S
Publication of WO2019134972A1 publication Critical patent/WO2019134972A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D7/00—Controlling wind motors 
    • F03D7/02—Controlling wind motors  the wind motors having rotation axis substantially parallel to the air flow entering the rotor
    • F03D7/022—Adjusting aerodynamic properties of the blades
    • F03D7/0224—Adjusting blade pitch
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2260/00—Function
    • F05B2260/42—Storage of energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2260/00—Function
    • F05B2260/70—Adjusting of angle of incidence or attack of rotating blades
    • F05B2260/76—Adjusting of angle of incidence or attack of rotating blades the adjusting mechanism using auxiliary power sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2260/00—Function
    • F05B2260/845—Redundancy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2270/00—Control
    • F05B2270/60—Control system actuates through
    • F05B2270/604—Control system actuates through hydraulic actuators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E70/00—Other energy conversion or management systems reducing GHG emissions
    • Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin

Definitions

  • the present invention relates to a hydraulic circuit for con trolling the pitch angle of the blades of a wind turbine.
  • the hydraulic circuit of the present invention comprises in par ticular redundant features.
  • any wind turbine is provided with a pitch actuation circuit for regulating the pitch angle of each blade, i.e. the angular position of each blade about the respective blade longitudinal axis.
  • the pitch actuation circuit may be hydraulic .
  • the pitch angle defines the angle of attack of the blades in relationship to the direction of the wind to control the production of power of the wind turbine.
  • two hydraulic cylinders are provided for actuating the pitch angle of each blade, one being able alone to control the pitch angle, in case the other fails.
  • the cylinders are connected to a source of hydraulic pressure for normal operations .
  • Each accumulator bank is normally associated to relief valves, security valves and ball valves for relieving pressure.
  • a hydraulic circuit for controlling the pitch angle of a plurality of blades of a wind turbine comprises:
  • first accumulator bank comprising at least one first hydraulic fluid accumulator, said first accumulator bank being connected to each of said first plurality of actuating cylinders ,
  • a second accumulator bank comprising at least one second hydraulic fluid accumulator, said second accumulator bank being connected to each of said second plurality of actuating cylinders .
  • Two accumulator banks are used for managing emergencies for all the first plurality and the second pluralities of actuating cylinders.
  • the present invention permits to use two accumulator banks instead of six, without reducing the level of redundancy.
  • the hydraulic circuit comprises:
  • each security valve of the first plurality of security valves being respectively interposed between the first accumulator bank and one
  • each security valve of the second plurality of security valves being respectively interposed between the second accumulator bank and one respective actuating cylinder of the second plurality of actuating cylinders.
  • Each plurality of security valves comprises a number of valves which corresponds to the number of blades of the turbine.
  • the total number of security valves according to the present invention is the double of the number of the blades. In prior art circuits where two accumulator banks and two hydraulic cylinders for each blade of the wind turbine are used, the total number of security valves is four times the number of the blades. If the wind turbine comprises three blades, the present invention permits to use six security valves instead of twelve, without reducing the level of redundancy .
  • the hydraulic circuit comprises:
  • a first relief valve connected to the first accumulator bank for controlling the pressure in the at least one first hydraulic fluid accumulator
  • a second relief valve connected to the second accumulator bank for controlling the pressure in the at least one second hydraulic fluid accumulator.
  • the present invention permits to use two relief valves instead of six, without reducing the level of redundancy .
  • the hydraulic circuit comprises:
  • first pressure sensor connected to first accumulator bank for measuring the pressure in the at least one first
  • One pressure sensor is used in association with each
  • the present invention permits to use two pressure sensors instead of six, without reducing the level of redundancy.
  • the hydraulic circuit comprises:
  • first ball valve connected to first accumulator bank for relieving the pressure from the first accumulator bank
  • the present invention permits to use two ball valves instead of six, without reducing the level of redundancy .
  • any of the first accumulator bank and the second accumulator bank comprises two respective hydraulic fluid accumulators. This permits to conveniently split the fluid reserve in the accumulator bank in two distinct hydraulic fluid
  • Figure 1 shows a schematic section of a wind turbine to which the hydraulic circuit present invention can be applied for controlling the pitch angle of a plurality of blades of the wind turbine.
  • Figure 2 shows a hydraulic scheme, illustrating the hy
  • FIG. 1 shows a wind turbine 1 according to the invention.
  • the wind turbine 1 comprises a tower 2, which is mounted on a non-depicted foundation.
  • a nacelle 3 is arranged on top of the tower 2.
  • the wind turbine 1 further comprises a wind rotor 5 having at least one blade 4 (in the embodiment of Figure 1, the wind rotor comprises three blades 4, of which only two blades 4 are visible) .
  • the wind rotor 5 is rotatable around a rota tional axis Y.
  • the blades 4 extend substantially radially with respect to the rotational axis Y and along a respective longitudinal ax is X .
  • the wind turbine 1 comprises an electric generator 11, in cluding a stator 20 and a rotor 30.
  • the rotor 30 is rotatable with respect to the stator 20 about the rotational axis Y.
  • the wind rotor 5 is rotationally coupled with the electric generator 11 either directly, e.g. direct drive or by means of a rotatable main shaft 9 and/or through a gear box (not shown in Figure 1) .
  • a schematically depicted bearing assembly 8 is provided in order to hold in place the main shaft 9 and the rotor 5.
  • the rotatable main shaft 9 extends along the ro tational axis Y.
  • the wind rotor 5 comprises three flanges 15 for connecting a respective blade 4 to the wind rotor 5.
  • a pitch bearing is interposed between each blade flange 15 and the respective blade 4.
  • a hydraulic pitch actuation circuit 100 is associat ed to the pitch bearings of the blades 4 for regulating the pitch angle of each blade, i.e. the angular position of each blade about the respective blade longitudinal axis X.
  • the hydraulic circuit 100 comprises a first plurality of actuating cylinders 110 and a second plurality of actuating cylinders 120.
  • Each of the plurality of blades 4 are actuated by one cylinder of the first plurality of actuating cylinders 110 and, for redundancy purposes, by one cylinder of the second plurality of actuating cylinders 120.
  • each of the first plurality and second plurality of actuating cylinders 110, 120 comprises therefore three cylinders.
  • actuating cylinder 110 and the second actuating cylinder 120 are connected between a source of pressure 200 and a pressure discharge 300.
  • a distribution valve 210 with three positions and four ports is connected between the first actuating cylinder 110 and the source of pressure 200 and the pressure discharge 300 and between the second actuating cylinder 120 and the source of pressure 200 and the pressure discharge 300, in order to assure the regulation of the pitch angle during normal operations.
  • the working of the first plurality and second plurality of actuating cylinders 110 i.e. normal regulation of the pitch angle, the working of the first plurality and second plurality of actuating cylinders 110,
  • the hydraulic circuit 100 comprises a first accumulator bank 150 connected to each of the first plurality of actuating cylinders 110.
  • the first accumulator bank 150 comprises two first hydraulic fluid accumulators 151, 152.
  • a first plurality of security valves 180 is provided. Each security valve 180 is respectively interposed between the first accumulator bank 150 and one respective actuating cylinder of the first plurality of actuating cylinders 110.
  • the hydraulic circuit 100 further comprises a first relief valve 153 connected to the first accumulator bank 150 for controlling the pressure in the first hydraulic fluid
  • the first relief valve 153 is also connected in a way that it will additionally relieve any overpressure in the first plurality of actuating cylinders 110.
  • a first pressure sensor 155 is connected to the first
  • a first ball valve 154 is connected to the first accumulator bank 150 for relieving the pressure from the first accumulator bank 150, thus permitting for example the maintenance and/or substitution of any of the first hydraulic fluid accumulators 151, 152.
  • the hydraulic circuit 100 comprises a second accumulator bank 160 connected to each of the second plurality of actuating cylinders 120.
  • the second accumulator bank 160 comprises two second
  • a second plurality of security valves 190 is provided. Each security valve 190 is respectively interposed between the second accumulator bank 160 and one respective actuating cylinder of the second plurality of actuating cylinders 120.
  • the hydraulic circuit 100 further comprises a second relief valve 163 connected to the second accumulator bank 160 for controlling the pressure in the second hydraulic fluid accumulators 161, 162.
  • the second relief valve 163 is also connected in a way that it will additionally relieve any overpressure in the second hydraulic cylinders 120.
  • a second pressure sensor 165 is connected to the second accumulator bank 160 for measuring the pressure in the second hydraulic fluid accumulators 161, 162.
  • a second ball valve 164 is connected to the second accumulator bank 160 for relieving the pressure from the second accumulator bank 160, thus permitting the maintenance and/or substitution of any of the second hydraulic fluid accumulators 161, 162.
  • the hydraulic circuit 100 of the present invention permits to achieve the required level of redundancy also during
  • the required level of redundancy is achieved by a minimum number of each of the above mentioned components.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Wind Motors (AREA)

Abstract

The invention relates to a hydraulic circuit (100) for controlling the pitch angle of a plurality of blades (4) of a wind turbine (1). The hydraulic circuit (100) comprises: - a first plurality of actuating cylinders (110), each of said plurality of blades (4) being actuated by one cylinder of said first plurality of actuating cylinders (110), - a second plurality of actuating cylinders (120), each of said plurality of blades (4) being actuated by one cylinder of said second plurality of actuating cylinders (120), - a first accumulator bank (150) comprising at least one first hydraulic fluid accumulator (151, 152), said first accumulator bank (150) being connected to each of said first plurality of actuating cylinders (110), - a second accumulator bank (160) comprising at least one second hydraulic fluid accumulator (161, 162), said second accumulator bank (160) being connected to each of said second plurality of actuating cylinders (120).

Description

DESCRIPTION
Redundant hydraulic pitch control
Field of invention
The present invention relates to a hydraulic circuit for con trolling the pitch angle of the blades of a wind turbine. The hydraulic circuit of the present invention comprises in par ticular redundant features.
Art Background
Normally, any wind turbine is provided with a pitch actuation circuit for regulating the pitch angle of each blade, i.e. the angular position of each blade about the respective blade longitudinal axis. In particular the pitch actuation circuit may be hydraulic . The pitch angle defines the angle of attack of the blades in relationship to the direction of the wind to control the production of power of the wind turbine.
As the regulation of the pitch angle is essential for the functioning of the wind turbine, some level of redundancy is implemented in the pitch actuation circuit.
Typically, in a hydraulic pitch actuation circuit, two hydraulic cylinders are provided for actuating the pitch angle of each blade, one being able alone to control the pitch angle, in case the other fails. The cylinders are connected to a source of hydraulic pressure for normal operations .
Accumulator banks are provided in the hydraulic pitch
actuation circuit for managing emergency where not enough hydraulic pressure is provided by the hydraulic source to the hydraulic cylinders. The principle of redundancy is applied also to the accumulator banks. Each accumulator banks is normally associated to relief valves, security valves and ball valves for relieving pressure.
The great number of components above described provides the required level of redundancy, but produces as drawback also a high level of associated costs and complexity.
It is therefore still desirable to provide a new hydraulic circuit for controlling the pitch angle of the blades of a wind turbine, limiting costs and complexity of the system without compromising the level of redundancy with respect to the above described prior art.
Summary of the Invention
In order to achieve the object defined above, a hydraulic circuit for controlling the pitch angle of a plurality of blades of a wind turbine is provided in accordance to the in dependent claims. The dependent claims describe advantageous developments and modifications of the invention.
According to an aspect of the present invention, a hydraulic circuit for controlling the pitch angle of a plurality of blades of a wind turbine comprises:
- a first plurality of actuating cylinders, each of said plurality of blades being actuated by one cylinder of said first plurality of actuating cylinders,
- a second plurality of actuating cylinders, each of said plurality of blades being actuated by one cylinder of said second plurality of actuating cylinders,
- a first accumulator bank comprising at least one first hydraulic fluid accumulator, said first accumulator bank being connected to each of said first plurality of actuating cylinders ,
- a second accumulator bank comprising at least one second hydraulic fluid accumulator, said second accumulator bank being connected to each of said second plurality of actuating cylinders .
Two accumulator banks are used for managing emergencies for all the first plurality and the second pluralities of actuating cylinders. With respect to prior art circuits where two accumulator banks for each of the three blades of the wind turbine are used, the present invention permits to use two accumulator banks instead of six, without reducing the level of redundancy.
According to exemplary embodiments of the present invention, the hydraulic circuit comprises:
- a first plurality of security valves, each security valve of the first plurality of security valves being respectively interposed between the first accumulator bank and one
respective actuating cylinder of the first plurality of actuating cylinders,
- a second plurality of security valves, each security valve of the second plurality of security valves being respectively interposed between the second accumulator bank and one respective actuating cylinder of the second plurality of actuating cylinders.
Each plurality of security valves comprises a number of valves which corresponds to the number of blades of the turbine. The total number of security valves according to the present invention is the double of the number of the blades. In prior art circuits where two accumulator banks and two hydraulic cylinders for each blade of the wind turbine are used, the total number of security valves is four times the number of the blades. If the wind turbine comprises three blades, the present invention permits to use six security valves instead of twelve, without reducing the level of redundancy .
According to exemplary embodiments of the present invention, the hydraulic circuit comprises:
- a first relief valve connected to the first accumulator bank for controlling the pressure in the at least one first hydraulic fluid accumulator,
- a second relief valve connected to the second accumulator bank for controlling the pressure in the at least one second hydraulic fluid accumulator.
One relief valve is used in association with each accumulator bank. With respect to prior art circuits where two
accumulator banks for each of the three blades of the wind turbine are used, the present invention permits to use two relief valves instead of six, without reducing the level of redundancy .
According to exemplary embodiments of the present invention, the hydraulic circuit comprises:
- a first pressure sensor connected to first accumulator bank for measuring the pressure in the at least one first
hydraulic fluid accumulator,
- a second relief valve connected to second accumulator bank for measuring the pressure in the at least one second
hydraulic fluid accumulator.
One pressure sensor is used in association with each
accumulator bank. With respect to prior art circuits where two accumulator banks for each of the three blades of the wind turbine are used, the present invention permits to use two pressure sensors instead of six, without reducing the level of redundancy.
According to exemplary embodiments of the present invention, the hydraulic circuit comprises:
- a first ball valve connected to first accumulator bank for relieving the pressure from the first accumulator bank,
- a second ball valve connected to second accumulator bank for relieving the pressure from the second accumulator bank. One ball valve is used in association with each accumulator bank. With respect to prior art circuits where two
accumulator banks for each of the three blades of the wind turbine are used, the present invention permits to use two ball valves instead of six, without reducing the level of redundancy .
According to exemplary embodiments of the present invention, any of the first accumulator bank and the second accumulator bank comprises two respective hydraulic fluid accumulators. This permits to conveniently split the fluid reserve in the accumulator bank in two distinct hydraulic fluid
accumulators . Brief Description of the Drawings
The above mentioned attributes and other features and advantages of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Figure 1 shows a schematic section of a wind turbine to which the hydraulic circuit present invention can be applied for controlling the pitch angle of a plurality of blades of the wind turbine.
Figure 2 shows a hydraulic scheme, illustrating the hy
draulic circuit of the present invention,
Detailed Description
The illustrations in the drawings are schematic. It is noted that in different figures, similar or identical elements are provided with the same reference signs.
Figure 1 shows a wind turbine 1 according to the invention. The wind turbine 1 comprises a tower 2, which is mounted on a non-depicted foundation. A nacelle 3 is arranged on top of the tower 2.
The wind turbine 1 further comprises a wind rotor 5 having at least one blade 4 (in the embodiment of Figure 1, the wind rotor comprises three blades 4, of which only two blades 4 are visible) . The wind rotor 5 is rotatable around a rota tional axis Y.
The blades 4 extend substantially radially with respect to the rotational axis Y and along a respective longitudinal ax is X . The wind turbine 1 comprises an electric generator 11, in cluding a stator 20 and a rotor 30. The rotor 30 is rotatable with respect to the stator 20 about the rotational axis Y.
The wind rotor 5 is rotationally coupled with the electric generator 11 either directly, e.g. direct drive or by means of a rotatable main shaft 9 and/or through a gear box (not shown in Figure 1) . A schematically depicted bearing assembly 8 is provided in order to hold in place the main shaft 9 and the rotor 5. The rotatable main shaft 9 extends along the ro tational axis Y.
The wind rotor 5 comprises three flanges 15 for connecting a respective blade 4 to the wind rotor 5. A pitch bearing is interposed between each blade flange 15 and the respective blade 4. A hydraulic pitch actuation circuit 100 is associat ed to the pitch bearings of the blades 4 for regulating the pitch angle of each blade, i.e. the angular position of each blade about the respective blade longitudinal axis X.
With reference to the hydraulic scheme of Figure 2 , the hydraulic pitch actuation circuit 100 for controlling the pitch angle of the blades 4 is described.
The hydraulic circuit 100 comprises a first plurality of actuating cylinders 110 and a second plurality of actuating cylinders 120. Each of the plurality of blades 4 are actuated by one cylinder of the first plurality of actuating cylinders 110 and, for redundancy purposes, by one cylinder of the second plurality of actuating cylinders 120. With reference to the wind turbine 1 of figure 1 with three blades 4, each of the first plurality and second plurality of actuating cylinders 110, 120 comprises therefore three cylinders.
For each of the plurality of blades 4, both the first
actuating cylinder 110 and the second actuating cylinder 120 are connected between a source of pressure 200 and a pressure discharge 300. A distribution valve 210 with three positions and four ports is connected between the first actuating cylinder 110 and the source of pressure 200 and the pressure discharge 300 and between the second actuating cylinder 120 and the source of pressure 200 and the pressure discharge 300, in order to assure the regulation of the pitch angle during normal operations. To such purpose, i.e. normal regulation of the pitch angle, the working of the first plurality and second plurality of actuating cylinders 110,
120 and of distribution valve 210 is not a specific object of the present invention and therefore not described in further detail .
To manage emergency cases, where not enough hydraulic
pressure is provided by the hydraulic source 200 to the first hydraulic cylinders 110, the hydraulic circuit 100 comprises a first accumulator bank 150 connected to each of the first plurality of actuating cylinders 110. The first accumulator bank 150 comprises two first hydraulic fluid accumulators 151, 152.
To manage overpressures in the branches connecting the first accumulator bank 150 and the first hydraulic cylinders 110 a first plurality of security valves 180 is provided. Each security valve 180 is respectively interposed between the first accumulator bank 150 and one respective actuating cylinder of the first plurality of actuating cylinders 110. The hydraulic circuit 100 further comprises a first relief valve 153 connected to the first accumulator bank 150 for controlling the pressure in the first hydraulic fluid
accumulators 151, 152. The first relief valve 153 is also connected in a way that it will additionally relieve any overpressure in the first plurality of actuating cylinders 110.
A first pressure sensor 155 is connected to the first
accumulator bank 150 for measuring the pressure in the first hydraulic fluid accumulators 151, 152. A first ball valve 154 is connected to the first accumulator bank 150 for relieving the pressure from the first accumulator bank 150, thus permitting for example the maintenance and/or substitution of any of the first hydraulic fluid accumulators 151, 152.
For redundancy reasons during emergency cases, where not enough hydraulic pressure is provided by the hydraulic source 200 to the second hydraulic cylinders 120, the hydraulic circuit 100 comprises a second accumulator bank 160 connected to each of the second plurality of actuating cylinders 120. The second accumulator bank 160 comprises two second
hydraulic fluid accumulators 161, 162.
To manage overpressures in the branches connecting the second accumulator bank 160 and the second hydraulic cylinders 120 a second plurality of security valves 190 is provided. Each security valve 190 is respectively interposed between the second accumulator bank 160 and one respective actuating cylinder of the second plurality of actuating cylinders 120. The hydraulic circuit 100 further comprises a second relief valve 163 connected to the second accumulator bank 160 for controlling the pressure in the second hydraulic fluid accumulators 161, 162. The second relief valve 163 is also connected in a way that it will additionally relieve any overpressure in the second hydraulic cylinders 120.
A second pressure sensor 165 is connected to the second accumulator bank 160 for measuring the pressure in the second hydraulic fluid accumulators 161, 162. A second ball valve 164 is connected to the second accumulator bank 160 for relieving the pressure from the second accumulator bank 160, thus permitting the maintenance and/or substitution of any of the second hydraulic fluid accumulators 161, 162.
The hydraulic circuit 100 of the present invention permits to achieve the required level of redundancy also during
emergency cases with a total number of:
- two accumulator banks 150, 160,
- six safety valves 180, 190,
- two relief valves,
- two pressure sensors 155, 165,
- two ball valves 154, 164.
In accordance to the present invention the required level of redundancy is achieved by a minimum number of each of the above mentioned components.

Claims

1. A hydraulic circuit (100) for controlling the pitch angle of a plurality of blades (4) of a wind turbine (1), the hydraulic circuit (100) comprising:
- a first plurality of actuating cylinders (110), each of said plurality of blades (4) being actuated by one cylinder of said first plurality of actuating cylinders (110),
- a second plurality of actuating cylinders (120), each of said plurality of blades (4) being actuated by one cylinder of said second plurality of actuating cylinders (120),
- a first accumulator bank (150) comprising at least one first hydraulic fluid accumulator (151, 152), said first accumulator bank (150) being connected to each of said first plurality of actuating cylinders (110),
- a second accumulator bank (160) comprising at least one second hydraulic fluid accumulator (161, 162), said second accumulator bank (160) being connected to each of said second plurality of actuating cylinders (120).
2. The hydraulic circuit (100) according to claim 1, wherein the hydraulic circuit (100) comprises:
- a first plurality of security valves (180), each security valve of the first plurality of security valves (180) being respectively interposed between the first accumulator bank (150) and one respective actuating cylinder of the first plurality of actuating cylinders (110),
- a second plurality of security valves (190), each security valve of the second plurality of security valves (190) being respectively interposed between the second accumulator bank (160) and one respective actuating cylinder of the second plurality of actuating cylinders (120).
3. The hydraulic circuit (100) according to claim 1 or 2, wherein the hydraulic circuit (100) comprises:
- a first relief valve (153) connected to the first
accumulator bank (150) for controlling the pressure in the at least one first hydraulic fluid accumulator (151, 152), - a second relief valve (163) connected to the second
accumulator bank (160) for controlling the pressure in the at least one second hydraulic fluid accumulator (161, 162) .
4. The hydraulic circuit (100) according to any of the preceding claims, wherein the hydraulic circuit (100)
comprises :
- a first pressure sensor (155) connected to first
accumulator bank (150) for measuring the pressure in the at least one first hydraulic fluid accumulator (151, 152),
- a second pressure sensor (165) connected to second
accumulator bank (160) for measuring the pressure in the at least one second hydraulic fluid accumulator (161, 162) .
5. The hydraulic circuit (100) according to any of the preceding claims, wherein the hydraulic circuit (100)
comprises :
- a first ball valve (154) connected to first accumulator bank (150) for relieving the pressure from the first
accumulator bank (150),
- a second ball valve (164) connected to second accumulator bank (160) for relieving the pressure from the second
accumulator bank (160) .
6. The hydraulic circuit (100) according to any of the preceding claims, wherein any of the first accumulator bank (150) and the second accumulator bank (160) comprises two respective hydraulic fluid accumulators (151, 152; 161, 162).
PCT/EP2019/050169 2018-01-05 2019-01-04 Redundant hydraulic pitch control WO2019134972A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201862613864P 2018-01-05 2018-01-05
US62/613,864 2018-01-05

Publications (1)

Publication Number Publication Date
WO2019134972A1 true WO2019134972A1 (en) 2019-07-11

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Application Number Title Priority Date Filing Date
PCT/EP2019/050169 WO2019134972A1 (en) 2018-01-05 2019-01-04 Redundant hydraulic pitch control

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WO (1) WO2019134972A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2071780A (en) * 1980-03-17 1981-09-23 United Technologies Corp Wind turbine blade pitch control system
EP2458201A1 (en) * 2010-11-26 2012-05-30 Vestas Wind Systems A/S Wind turbine with hydraulic blade pitch system
CN103340056A (en) * 2013-07-24 2013-10-09 中国灌溉排水发展中心 Wind and light complementation micropower drip irrigation system
CN105298744A (en) * 2015-09-25 2016-02-03 三一重型能源装备有限公司 Braking hydraulic system of wind driven generator and wind driven generator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2071780A (en) * 1980-03-17 1981-09-23 United Technologies Corp Wind turbine blade pitch control system
EP2458201A1 (en) * 2010-11-26 2012-05-30 Vestas Wind Systems A/S Wind turbine with hydraulic blade pitch system
CN103340056A (en) * 2013-07-24 2013-10-09 中国灌溉排水发展中心 Wind and light complementation micropower drip irrigation system
CN105298744A (en) * 2015-09-25 2016-02-03 三一重型能源装备有限公司 Braking hydraulic system of wind driven generator and wind driven generator

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