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
  • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
  • F03D1/02—Wind motors with rotation axis substantially parallel to the air flow entering the rotor  having a plurality of rotors
• • 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
  • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
  • F03D13/20—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
• • 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
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/70—Wind energy
  • Y02E10/728—Onshore wind turbines

Definitions

• the present disclosure relates to a multirotor (MR) wind turbine comprising a plurality of units for supporting a conversion assembly.
• the conversion assembly can convert wind energy by rotation of a rotor about a rotor axis.
• the MR wind turbine comprises a tower extending in an upwards direction, and a load carrying structure which is carried by the tower via a main yaw assembly located between a first section and a second section of the load carrying structure.
• the main yaw assembly allows yawing of the load carrying structure relative to the tower.
• the MR wind turbine may have two or more units, e.g. four units, e.g. placed in two sets of two units on different load carrying structures in different heights.
• Wind turbines normally comprise one or more energy generating units configured, when the wind turbine is in a final, assembled state, to convert wind energy.
• Such units typically comprise a machine housing, sometimes referred to as gondola or nacelle, and in a final, assembled, state, the energy generating units comprise a load carrying hub carrying one or more wind turbine blades.
• the wind acts on the wind turbine blades, thereby converting the wind energy into rotation of the hub.
• the rotational movement of the hub is transferred e.g. to a generator, either via a gear arrangement or, in case the wind turbine is of a so-called direct drive type, the rotation is transferred directly without a gear.
• electrical energy is generated, which may be supplied to a power grid.
• Some wind turbines are provided with two or more energy generating units to increase the total power produced by the wind turbine, without having to provide the wind turbine with one very large, and therefore heavy, energy generating unit.
• Such wind turbines are sometimes referred to as 'multirotor wind turbines', in short MR wind turbines.
• the term “energy generating unit” comprises “a unit” and “a conversion assembly”.
• the unit supports and at least partly encapsulates the conversion assembly, and the conversion assembly is configured for converting wind energy e.g. into electrical energy.
• the conversion assembly includes inter alia the rotor, hub, and blades of the wind turbine.
• the disclosure provides an MR wind turbine wherein the units are attached to the first section and/or to the second section via a local yaw assembly allowing rotation, i.e. so called "yawing" of the unit relative to the load carrying structure.
• the units may define a front part and a rear part, the front part, in the final assembled state being towards the hub.
• the front and rear parts are on opposite sides of an axis of rotation for the local yaw assembly.
• the units comprise an entrance structure into an internal space of the unit, the entrance structure being accessible from the load carrying structure in at least one parked position of the unit relative to the load carrying structure, and the local yaw assembly allows yawing of the unit relative to the load carrying structure to each parked position.
• the unit In the parked position, the unit may be stopped or idling and ready for maintenance or repair work.
• the rotor axis may extend along the load carrying structure in each parked position.
• the rotor axis is within plus or minus 10 degrees from being parallel with the load carrying structure. This corresponds to plus or minus 10 degrees to a direction of a vertical plane through the load carrying structure.
• the units may comprise a gondola or nacelle defining walls encapsulating the internal space.
• the units may be in a building state not yet comprising all components necessary for converting the wind energy or in a final, assembled, state comprising all necessary components for converting wind energy including a rotor with a hub carrying blades for converting the wind energy by rotation of the rotor about a rotor axis.
• the unit facilitates conversion of wind energy by rotation of a rotor about a rotor axis, it refers to the ability in the final, assembled state, and does not imply that the rotor is necessarily installed since the unit may be in a building state and not yet fitted with components necessary for such conversion.
• the entrance structure comprises one or more openings in a bottom or roof panel of the unit, and access between the load carrying structure and the internal space is upwards or downwards.
• the entrance structure comprises one or more openings in a side panel of the unit, and access between the load carrying structure and the internal space is sideways. This may be useful e.g. when the rotor axis is not along the load carrying structure, e.g. in a 45-degree position with respect to the load carrying structure.
• the entrance structure into the internal space of the unit may be accessible vertically above or below the load carrying structure in at least one of the parked positions of the unit relative to the load carrying structure.
• a vertical line can be defined from the entrance structure to the load carrying structure.
• This facilitates inter alia use of cranes for lifting items into and out of the entrance structure directly from the load carrying structure. It also facilitates use of ladders arranged to slide vertically down from the entrance structure onto the load carrying structure or into an internal passageway in the load carrying structure. Generally, it facilitates use of gravity in support for transport between the internal space and the load carrying structure.
• the entrance structure comprises one or more openings in a bottom or roof panel of the unit, at least a part of the opening or the entire opening may be vertically above the load carrying structure.
• the entrance structure comprises one or more openings in a side panel of the unit
• a crane rope can be hoisted from the opening and vertically down onto the load carrying structure.
• the entrance structure may comprise a front entrance in the front part and comprising one or more openings into the internal space to allow entrance into the internal space of the unit from the load carrying structure in a first of the at least one parked positions.
• the first parked position may be a position where the hub of the rotor is located vertically above or below the load carrying structure, and the front entrance may be directly into the hub. This allows direct access from the load carrying structure into the hub and thereby easy access for replacement of components therein, e.g. components of a blade pitching system or access for personal, e.g. for rescue purpose.
• the entrance structure may comprise a rear entrance in the rear part, and comprising one or more openings into the internal space to allow entrance into the internal space of the units from the load carrying structure in a second of the at least one parked positions.
• the second position may be a position where the hub of the unit points away from the tower, and the opposite, rear end, of the unit is located above or below the load carrying structure.
• At least one of x and y e.g. at least one of the front entrance and the rear entrance, means x or y or a combination of x and y.
• the entrance structure When not in use, the entrance structure may be closed. At least one of the front entrance and the rear entrance may be closed by a hatch structure comprising one or more hatches, e.g. a door which can open or close the entrance, and e.g. comprising automatic locking means operating dependent on a position of the unit relative to the load carrying structure, particularly to ensure that the entrance is sealed when the position of the unit relative to the load carrying structure does not allow access there between.
• a hatch structure comprising one or more hatches, e.g. a door which can open or close the entrance, and e.g. comprising automatic locking means operating dependent on a position of the unit relative to the load carrying structure, particularly to ensure that the entrance is sealed when the position of the unit relative to the load carrying structure does not allow access there between.
• the load carrying structure may form an internal passageway between the tower and an exit which is accessible from the entrance structure in each parked position. In that way, spare parts and personnel may access the unit via the tower and a passageway inside the load carrying structure. This may increase safety and comfort for the personnel.
• the entrance structure into the internal space of the unit may be accessible vertically above or below the exit. This means that a vertical line can be defined from the entrance structure to the exit on the load carrying structure. This facilitates use of cranes for lifting items into and out of the entrance structure directly from the internal passageway of the load carrying structure.
• the entrance structure may be within an outer limit of the exit, or the exit may be within an outer limit of the entrance structure.
• the exit may be sealable by a closure structure comprising automatic locking means operating depending on a position of the unit relative to the load carrying structure to prevent the personnel from leaving the internal passageway unless the unit is in a position suitable for entrance directly from the exit of the internal passageway of the load carrying structure.
• An encapsulated entrance way between the entrance structure and the load carrying structure may further increase safety.
• the encapsulated entrance may be movable or static.
• a movable encapsulation may comprise a lock, e.g. a bellow or tubular shaped lock movable from one or both of the unit and load carrying structure towards the other one of the unit and load carrying structure.
• a static encapsulated entrance could comprise a lock or a section of a lock, e.g. a tubular lock extending from one or both of the unit and load carrying structure towards the other one of the unit and load carrying structure, and forming a slim gap sufficient for the unit to move relative to the load carrying structure but narrow enough to make entrance safe and almost completely encapsulated.
• the entrance way may be accessible in one, or all of the at least one parked positions.
• the disclosure provides a method of providing access from a tower of a multirotor wind turbine comprising a plurality of units configured to convert wind energy by rotation of a rotor about a rotor axis and carried by the tower via a load carrying structure.
• the method comprises rotating one of the units relative to the load carrying structure to a parked position in which an entrance structure into an internal space of the unit is accessible from the load carrying structure.
• the internal space in the unit is subsequently accessed from the load carrying structure and objects such as personnel, spare parts, and tools can be communicated between the load carrying structure and the internal space.
• the objects may be communicated vertically between the internal space and the load carrying structure, e.g. vertically through an exit from an internal passageway in the load carrying structure.
• the method may be used when carrying out service on the unit which is yawed to the parked position.
• An azimuth angle of the rotor may be locked by a rotor braking structure while rotating the unit relative to the load carrying structure. This may protect the wind turbine against damage by collision between blades and the load carrying structure.
• the rotor may e.g. be locked in a position where one blade is between zero and 30 degrees to vertical. This corresponds to a position being plus or minus 30 degrees and thereby provides a 60 degrees range in which the blades can be positioned prior to the movement to the parked position.
• the azimuth angle of the rotor may, alternatively, be changed while rotating the unit relative to the load carrying structure.
• the change of the azimuth angle may, in that case, be coordinated with the rotation of the unit relative to the load carrying structure to prevent collision between a blade of the rotor and the load carrying structure.
• the azimuth angle is changed from a position where one blade is between 40 and 80 degrees to vertical to a position where one blade is between zero and 20 degrees to vertical.
• Objects such as personnel and spare parts may be transported between the internal space and an internal passageway inside the load carrying structure, and particularly by use of a crane lifting rope extending vertically between the entrance structure and the exit from the internal passageway. LIST OF DRAWINGS
• Fig. 1 illustrates an example of a front view of a MR wind turbine
• Fig. 2 is a top view of the multirotor wind turbine of Figs. 1;
• Fig. 3 shows a detail of the main yaw assembly;
• Fig. 4 illustrates the local yaw assembly of one of the units
• Fig. 5 illustrates schematically a top view of the MR wind turbine
• Figs. 6 and 7 illustrate schematically two different parked positions of the MR wind turbine; and Figs. 8-12 illustrate further details related to the entrance structure.
• Fig. 1 illustrates in a front view, a multirotor wind turbine 1 comprising a tower 2 carrying two load carrying structures 3.
• the load carrying structures 3 are arranged one above the other along the length of the tower 2.
• Each load carrying structure 3 comprises two sections 4, extending away from the tower 2 on opposite sides of the tower 2, as seen from the viewing angle of Fig. 1.
• Each section 4 carries a unit 5.
• the units 5 comprises a nacelle or gondola shaped encapsulation 6 and in an assembled state, it supports a rotor 7 carrying three wind turbine blades 8 thereby forming an energy generating unit.
• Each section 4 comprises a primary structure 9, in the form of a tube, and two secondary structures 10, in the form of double wires. In Fig. 1, only one of the secondary structures 10 for each section 4 is visible.
• the primary structures 9 extend away from the tower 2 along a direction which forms an acute angle with respect to a substantially vertical longitudinal axis defined by the tower 2.
• the primary structures 9 extend away from the tower 2 along an inclined upwards direction.
• the secondary structures 10 extend away from the tower 2 along a direction which is substantially perpendicular to the substantially vertical longitudinal axis defined by the tower 2. Thereby the secondary structures 10 extend away from the tower 2 along a substantially horizontal direction. Accordingly, an angle is defined between the direction in which primary structure 9 of a given section 4 extends, and the plane in which the secondary structures 10 of the section 4 extend.
• the primary structure 9 and the secondary structures 10 are attached to the tower 2 via a main yaw arrangement 11, allowing the entire load carrying structure 3 to perform yawing movements with respect to the tower 2 to direct the rotors 7 into the incoming wind.
• the MR wind turbine comprises a microprocessor-based wind turbine control system not illustrated.
• the control system is configured to control yaw functions of the MR wind turbine and handles different input signals defining at least one of wind speed, wind direction, air density and/or temperature, and wind speed and direction in gusts. Further, the control system receives a desired operational state e.g. full operation, reduced power, or deactivated.
• the control system may, depending on the implementation of the yaw assemblies, also receive error signals, loading signals, speed signals and other servo system related signals from servo drives included in each yaw assembly.
• control system is configured to output control signals for the main yaw structure and the local yaw structures.
• the disclosed MR wind turbine is an MR 2 turbine meaning that it carries 2 units. It may just as well carry more units, e.g. 3 or 4 units, e.g. two rows of two units in different altitude and carried by different load carrying structures.
• Fig. 2 is a top view of the multirotor wind turbine 1 of Figs. 1 and illustrates that the rotor axes 15 forms an angle to the prevailing wind direction illustrated by the arrow 16. In the illustrated MR wind turbine, this angle is not parallel to the rotor axes. The offset from parallel is chosen to prevent collision between the blades and the load carrying structure. The difference between the parallel direction and the direction of the rotor axes is sometimes referred to as toe-angle, in the illustrated embodiment, it is 6 degrees.
• This angle may, in one embodiment, be considered as the operational angle to the prevailing wind. In other embodiments, other angles, e.g. zero degrees, may be considered as the operational angle, i.e. the operational angle is an angle desired for the rotor axes relative to the prevailing wind direction during normal operation.
• Fig. 3 shows a detail of the multirotor wind turbine 1 of Figs. 1-2, illustrating the main yaw assembly attaching the load carrying structure 3 to the tower 2.
• One of the secondary structures 10 of each section 4 is attached to the spacer arrangement 12.
• the spacer arrangement 12 is attached to a movable part of the main yaw arrangement 11.
• the other secondary structure 10 of each section 4 is attached directly to the movable part of the main yaw arrangement 11.
• one of the secondary structures 10 is attached to the tower 2 via an attachment point arranged on a spacer arrangement 12, the attachment point thereby being arranged behind the tower 2 and at a distance from the tower 2.
• the other secondary structure 10 is attached to the tower 2 at an attachment point which is arranged in front of the tower 2 and close to the tower 2.
• the primary structure 9 extends from a position behind the tower 2 to a position in front of the tower 2. This allows the rotor 7 of each of the units 5 to be arranged in front of the tower 2, and in front of the primary structure 9 and both secondary structures 10. Thereby the wind turbine blades 8 are kept clear from these structures, and the risk of collision is minimized.
• Fig. 4 illustrates further details of the end of one section 4 of the load carrying structure 3.
• the end section comprises an interface 17 forming a local yaw assembly 18 for holding the unit 5 and allowing the unit to yaw relative to the load carrying structure 3.
• Fig. 5 illustrates schematically a top view of the MR wind turbine and illustrates the option of turning the load carrying structure 3 by use of the main yaw assembly 11 and turning each unit 5 by use of the local yaw assemblies 18.
• the three individual degrees of freedom are indicated by the arrows 19, 20, 21.
• the unit 23 is parked, e.g. during assembly or for service.
• the local yaw assembly is used for rotating the energy generating unit 23 such that a particular part of the energy generating unit 23 is accessible from load carrying structure.
• the unit 23 is moved to a parked position where the rear part is placed over the load carrying structure.
• the front part e.g. the hub
• the wind turbine is in a final, assembled state
• an azimuth control may be used to avoid blade collision with the load carrying structure.
• the rotor is rotated simultaneously with the yawing by use of the local yaw assembly.
• the coordinated control of the rotor rotation and the yawing of the unit could be carried out step-by-step or continuously.
• the rotor rotation may be obtained e.g. by a turner gear, different rotor lock positions, or in a generator motor mode where the generator is used as a motor for rotating the rotor.
• both the rotor and the local yaw assembly may be locked to prevent the blades from rotating or moving into the load carrying structure.
• a main yaw assembly lock and a local yaw assembly lock may be provided and controlled by the control system.
• the units 22, 23 are mounted on top of the load carrying structure.
• the entrance structure into the internal space is accessible vertically above the load carrying structure in at least one of the parked positions of the unit relative to the load carrying structure.
• the units 22, 23 could also be a "top hinged" in which case the units are hanging below the load carrying structure.
• the entrance structure into the internal space is accessible vertically below the load carrying structure in at least one of the parked positions of the unit relative to the load carrying structure.
• Figs 8 and 9 illustrate further details related to the parked positions shown in Figs. 6 and 7.
• the rear part is accessible from the load carrying structure via an opening 80 in a floor panel 81.
• the front part is accessible from the load carrying structure via an opening 80 in the hub 91.
• the entrance structure into the internal space of the unit is accessible vertically above the load carrying structure in both illustrations.
• a hatch structure including one or more hatches may be provided for preventing access through the opening 80 if the unit is not in the correct parked position.
• the MR wind turbine may e.g. comprise an electronic sensor, or a mechanical structure, which is triggered by correct positioning of the unit relative to the load carrying structure, e.g. for safe passage from the nacelle to the load carrying structure, and once correct position is achieved, the hatch structure is released for access through the opening 80.
• Fig. 10 illustrates a rear part being accessible from the load carrying structure via an opening 80 in a floor panel 81, and an encapsulated entrance way 101 between the entrance structure formed by the opening 80 and the load carrying structure 3. Since the entrance structure is vertically above the load carrying structure, the encapsulated entrance way can be unfolded from the unit by use of gravity.
• the encapsulated entrance way consists, in this embodiment, of an expandable bellow movable in the space between the opening 80 and the load carrying structure 3. In other embodiments, it may be an expandable fence etc.
• the encapsulated entranceway increases safety and prevents objects from falling during passage between the internal space and the load carrying structure.
• Figs. 11a and l ib illustrate a retractable ladder system 111 forming a safe entrance via the entrance structure.
• the entrance structure is vertically above the load carrying structure and the ladder may therefore be suspended from the unit by use of gravity.
• the load carrying structure 3 forms an internal passageway between the tower and an exit 112 which is accessible via the ladder from the entrance structure in each parked position.
• Fig. 12 illustrates the MR wind turbine from Figs. 11a and lib and including an encapsulated entrance way 101 forming a safer access.
• the encapsulated entrance way is formed by a closed bellow, e.g. a plastic bellow through which objects can be transported in a safe and shielded manner.
• blades are inspected or repaired by use of the load carrying structure as a working platform, particularly the secondary structures 10, c.f. previous Figs, may be used to carry a separate platform for carrying out work on the blades.
• a wind direction may be determined by a wind direction sensor attached to a first one of the units and that first unit may be placed in an operational position or in a position for access via the entrance structure based on the determined wind direction.
• the wind direction may be determined by a wind direction sensor attached to another one of the units, to the tower or elsewhere.
• the first unit may be placed in an operational position or in a position for access via the entrance structure based on the determined wind direction when corrected for the difference between the angles of the wind direction sensor and the first unit, e.g. based on input related to the angular positions of the yaw assemblies.

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• Engineering & Computer Science (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)

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• 2021
  • 2021-03-12 EP EP21714309.8A patent/EP4118323A1/de not_active Withdrawn
  • 2021-03-12 WO PCT/DK2021/050080 patent/WO2021180290A1/en active Application Filing

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