• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a system and method for a wind turbine power. The first object of the invention is to transmit power from a nacelle to the bottom of a windturbine in conductors with low resistance, hereby reducing power consumption in ca- bles. A further object of the invention is to avoid cable loops. The object of the pending patent application can be modified in that the grid side converter can be placed in a TBU (Tower Bottom Unit), where a DC power link is adapted to transmit DC power from the generator side converter in the nacelle to the grid side converter placed in the TBU. As a result, the power conversion into AC with grid frequency can be performed in the TBU (Tower Bottom Unit).
    公开号:DK201770003A1
    申请号:DKP201770003
    申请日:2017-01-04
    公开日:2018-08-21
    发明作者:Mølgaard Anders
    申请人:Envision Energy (Denmark) Aps；
    IPC主号:
    专利说明:

    (19) DANMARK (1°) DK 2017 70003 A1
    (12)
    PATENTANSØGNING
    Patent- og Varemærkestyrelsen lnt.CI.: F03D 80/80 (2016.01) H01L 39/00 (2006.01)
    Ansøgningsnummer: PA 2017 70003
    Indleveringsdato: 2017-01 -04
    Løbedag:2017-01-04
    Aim. tilgængelig: 2018-07-05
    Publiceringsdato: 2018-08-21
    Ansøger:
    ENVISION ENERGY (DENMARK) ApS, Randersvej 2A, 8600 Silkeborg, Danmark
    Opfinder:
    Anders Mølgaard, Nissetvej 40, 8600 Silkeborg, Danmark
    Fuldmægtig:
    Patrade A/S, Ceresbyen 75, 8000 Århus C, Danmark
    Titel: Superconducting system for converter DC link
    Fremdragne publikationer:
    WO 97/47878 A1
    US 2012/0025535 A1
    WO 2012/093942 A1
    EP 2 918 828 A1
    Sammendrag:
    The present invention relates to a system and method for a wind turbine power. The first object of the invention is to transmit power from a nacelle to the bottom of a windturbine in conductors with low resistance, hereby reducing power consumption in ca- bles. A further object of the invention is to avoid cable loops. The object of the pending patent application can be modified in that the grid side converter can be placed in a TBU (Tower Bottom Unit), where a DC power link is adapted to transmit DC power from the generator side converter in the nacelle to the grid side converter placed in the TBU. As a result, the power conversion into AC with grid frequency can be performed in the TBU (Tower Bottom Unit).
    Fortsættes...
    DK 2017 70003 A1
    DK 2017 70003 A1 i
    Superconducting system for converter DC link
    Field of the Invention
    The present invention relates to a system and method for a wind turbine comprising a nacelle placed rotatable in relation to a tower, which nacelle carries a rotatable hub, which hub carries at least two blades, which nacelle comprises a generator adapted to generate electric power, which nacelle comprises a generator side converter adapted to convert electric AC power into DC power, which wind turbine further comprises a grid side converter adapted for converting DC power into AC power.
    Background of the Invention
    Power converters to convert AC power with variable frequency from wind turbine generators into DC and back into AC with grid frequency are well known from prior art.
    Object of the Invention
    The first object of the invention is to transmit power from a nacelle to the bottom of a wind turbine in conductors with low resistance, hereby reducing power consumption in cables and cost.
    A further object of the invention is to avoid cable loops.
    Description of the Invention
    The object of the pending patent application can be fulfilled by a system as disclosed in the preamble to claim 1 and modified in that the grid side converter can be placed in a TBU (Tower Bottom Unit), where a DC power link is adapted to transmit DC power from the generator side converter in the nacelle to the grid side converter placed in the TBU.
    As a result, the power conversion into AC with grid frequency can be performed in the TBU. This means that some of the heavy components are removed from the nacelle
    DK 2017 70003 A1 down into the bottom of the tower. Hereby, the mechanical stress of the tower is reduced, simply because the total weight of the nacelle is reduced and the accessibility in tower and nacelle is increased. Furthermore, the power that has to be removed from the nacelle is reduced when the power conversion into the grid frequency is placed at the bottom of the tower.
    The system can be modified by letting the DC power link comprise superconducting conductors. Hereby, nearly no power consumption will be taken up in the power link by transmitting DC power from the nacelle down to the tower and into the grid converter. This means that the cable loop which is typically placed in the upper third of the tower is completely avoided. Also most of the power consumption that takes place in the cables is reduced. The cables are also partly hanging in the nacelle and hereby further increasing the weight of the nacelle. The superconducting conductors have a very low weight compared with traditional cables, which cables are performed by conductors made of copper or aluminium. Furthermore, the fastening of the cables into the tower is avoided, which means that the load of the tower is further reduced, seeing that the tower and the nacelle no longer have to carry the very heavy cables.
    The system can be further modified as the DC link comprises HTS (High Temperature Superconductors). Hereby, a further reduction of the electrical systems in the conductors is achieved. The HTS are operating with a temperature that is approximately 70 0 kelvin (K). Therefore, the power link has to be cooled down to a relatively low temperature in order to achieve the very low electric resistance.
    The system can be further modified in that the DC link comprises LTS (Low Temperature Superconductors). As a result, a further reduction in the electric resistance of the DC link is achieved. By applying LTS the temperature that they are operating at is as low as 30° K. Therefore, a cooling media has to be used in order to cool down the conductors. By transmitting power along a tower in a wind turbine using a LTS power link, the power transmission can be performed without any loss of power. Therefore, it is possible to increase the current of the LTS power link and the length of the power link is uncritical as long as the electric resistance is nearly zero. The LTS power link is taking up much less room in a tower compared with traditional cables.
    DK 2017 70003 A1
    The system can be further modified in that the LTS power link comprises at least a first and a second set of LTS conductors, which sets of conductors are electrically isolated, which sets of conductors are placed inside a thermal isolation, inside which thermal insulation a cryogen cooling media is circulated. Hereby, DC current with ± plurality can be transmitted through the LTS conductors. Placing the LTS conductors with isolation between each other and also isolated towards a cryogen cooling media has the effect that the cooling media is not directly in contact with the LTS conductors. By placing a further shield of isolating material around the LTS conductors and their isolation and forming a space in between for the cooling media, it is possible to keep the temperature of the LTS power link at approximately 30° K. The cooling media of course has to be generated inside the wind turbine where the cooling media is circulated into the LTS cables, sending the cooling media through an inlet and returning it through an outlet.
    The system can be further modified in that the power link is formed inside an isolated flexible tube, the flexible tube could be glass fiber with non-torsion waving (<45 degrees, e.g. biax, which flexible tube and power link is rotating with the nacelle up to more than 720 degrees in both rotating directions. Placing the LTS power link inside a partly flexible tube can lead to sufficient stiffness of the LTS power link, so the power link only has to be fastened inside the tower, maybe at the bottom of the tower and fastened at the nacelle. The flexible tube is so flexible that it is possible to let the tube rotate together with the nacelle where the length of the tube is able to take up the rotational movement of the top of the tube, because the tube is only fastened at the nacelle and at the bottom of the tower. Here it is possible to let the tube simply follow all movements of the nacelle. This is possible because the tower is relatively high. For a traditional wind turbine, the height of the turbine can be between 70 meters and 140 meters and in the future, even higher wind turbines will probably be built. By the mechanical connection of the tube which comprises the LTS superconductors, these conductors can be rotated together with the tube, as long as the nacelle is only rotated ± 720 degrees. In this way, the traditional cable loop is totally avoided in a wind turbine.
    The system can be further modified in that the power link is formed inside an isolated flexible tube, which tube is fastened mechanically and electrically to the generator side converter in the nacelle and to the grid side converter in the TBU. Hereby, the
    DK 2017 70003 A1 electrical and mechanical connections are made directly at the generator side converter in the nacelle and the other end of the tube comprising the LTS conductors is fastened at the grid side converter in the TBU.
    The pending patent application further concerns a method for transmitting power from a grid placed in a nacelle of a wind turbine as disclosed previously, whereby the method uses at least the following steps of operation:
    a. let the generator generate electric power
    b. convert the generated power to DC power by generator side converter
    c. transmit the DC power by a power link to TBU
    d. convert the DC power by the grid side converter into AC
    e. transmit the AC power generated by the grid side converter to a grid.
    Hereby it is possible to transmit power from the generator side converter to the grid side converter by a power link comprising superconductors. Hereby, the grid side converter is removed from the nacelle and placed as part of the TBU. This means that the weight of heavy cables is avoided and the total weight that has to be carried in the nacelle is reduced. Thereby, the total stress of the tower is also reduced in that the nacelle has less weight to carry.
    The method can be modified in that transmission of power is performed by superconducting conductors, which conductors are cooled by a cryogen cooling media. By cooling the superconducting conductors with a cryogen cooling media it is possible to cool down the conductors to a temperature that is as low as 30° K. In that way it is possible to transmit the power from a generator side converter and down into the TBU which comprises the grid side converter. This transmission takes place along a tower as long as the height of the tower, which in modern wind turbines may be as high as 140 meters and in the future maybe even higher. By using DC power links with superconducting conductors operating with low temperature it is possible to increase the
    DK 2017 70003 A1 current in the power link and it is possible to use a much longer power link without increasing power loss during transmission.
    Description of the Drawing
    Figure 1 shows a wind turbine.
    Figure 2 shows one possible embodiment for the invention.
    Figure 3 shows one possible invention of a DC power link.
    Detailed Description of the Invention
    Figure 1 shows a wind turbine (2) which comprises a nacelle (4) carried by a tower (6). Furthermore, a hub (8) and blades (10, 12) are indicated. Inside the nacelle (4) a generator (14) is placed, which is not visible in this figure. In the tower (6) a DC power link (22) is indicated.
    The hub (8) is rotated by blades (10, 12) and the rotational power that is generated is converted by a generator (14) into electric power. This electric power can, in this invention, be converted into DC and the DC can be transmitted by the DC power link (22) downwards to the TBU (20). In some situations the DC can be directly transmitted to a DC grid, however, mostly the DC will be converted into AC in the TBU.
    Figure 2 schematically shows the content of the electric system in a wind turbine (2). A nacelle (4) comprising a generator side converter (16) which is supplied from a generator (14) is indicated. A tower (6) is indicated where an LTS (28) is indicated. The tower (6) is connected to the TBU (20). The TBU (20) comprises a grid side converter (18) which is performing conversion of the received DC into a grid frequency.
    At first the power generated in the generator (14) is sent through different filtration means in order to avoid any high frequency noise from the generator, and hereafter the power is converted in the generator side converter (16) into DC. This DC is then transmitted through a LTS (28). When this DC is received in the TBU (20) the grid
    DK 2017 70003 A1 side converter (18) is converting the received DC into AC with the grid frequency. The conversion is performed in three phases so that the AC power that is transmitted through the grid is a three phase AC power.
    Figure 3 indicates one possible embodiment for a DC power link (22) which is operating using superconducting conductors. In figure 3 a first superconductor (30) and a second superconductor (32) are indicated. These two conductors are isolated by an electric isolation (33). The superconductors (30 and 32) and the electric isolation (33) is placed in a space, where cryogen cooling media (36) is circulated in order to keep the temperature as low as 30° K. Furthermore, a thermal isolation (34) and a flexible tube (38) are indicated.
    Placing the superconductors (30 and 32) inside the cryogen cooling media (36) can keep the temperature as low as possible for superconducting. The isolation (34) is placed around in order to perform a good isolation and hereby reduce the power needed for cooling of the superconductors. The DC power link (22) can be fastened directly in a nacelle (4) directly and electrically connected to the generator side converter (16). In the other end the power link (22) is fastened to the TBU (20) and electrically, the connection is made directly to the grid side converter (18). No further fastening of the power link (22) is necessary and because no fastening is performed along the tower it is possible that the power link (22) rotates together with the nacelle, because the length of the power link is as long as the tower. Therefore, 720 degrees rotation in both directions is possible with the power link. By using the power link, traditional cable loops are totally avoided and the power consumption during the transmission along the cables is avoided by using superconducting conductors.
    DK 2017 70003 A1
    A wind turbine
    A nacelle
    Tower
    Rotatable hub
    10, 12 Blades
    Generator
    Generator side converter
    Grid Side Converter
    TBU (Tower Bottom Unit)
    DC power link
    Superconducting conductors
    HTS (High Temperature Superconductors)
    LTS (Low Temperature Superconductors)
    First conductor
    Second conductors,
    Electric isolation
    Thermal isolation
    Cryogen cooling media
    Isolated flexible tube
    DK 2017 70003 A1
    权利要求:
    Claims (9)
    [1] 1. A wind turbine (2) comprising a nacelle (4) placed rotatable in relation to a tower (6), which nacelle (4) carries a rotatable hub (8), which hub (8) carries at least two blades (10, 12), which nacelle (4) comprises a generator (14) adapted to generate electric AC power, which nacelle (4) comprises a generator side converter (16) adapted to convert electric AC power into DC power, which wind turbine (2) further comprises a grid side converter (18) adapted for converting DC power into AC power, characterized in that the grid side converter (18) is placed in a TBU (Tower Bottom Unit) (20), where a DC power link (22) is adapted to transmit DC power from the generator side converter (16) in the nacelle (4) to the grid side converter (18) in the TBU (20).
    [2] 2. A wind turbine according to claim 1, characterized in that the DC power link (22) comprises superconducting conductors (24).
    [3] 3. A wind turbine according to claim 1 or 2, characterized in that the DC link (22) comprises HTS (High Temperature Superconductors) (26).
    [4] 4. A wind turbine according to claim 1 or 2, characterized in that the DC link (22) comprises LTS (Low Temperature Superconductors) (28).
    [5] 5. A wind turbine according to claim 3 or 4, characterized in that the power link (22) comprises at least a first (30) and a second (32) set of conductors, which set of conductors are electrically isolated, which set of conductors are placed inside a thermal isolation (34), inside which thermal insulation a cryogen cooling media (36) is circulated.
    [6] 6. A wind turbine according to any one of the claims 2-5, characterized in that the power link (22) is formed inside an isolated flexible tube (38), which flexible tube and power link is rotating with the nacelle up to at least 720 degrees in both rotating directions.
    [7] 7. A wind turbine according to any one of the claims 2-6, characterized in that the power link (22) is formed inside an isolated flexible tube (38), which tube (38) is fas
    DK 2017 70003 A1 tened mechanically and electrically to the generator side converter (16) in the nacelle (4) and to the grid side converter (18) the TBU (Tower Bottom Unit) (20).
    [8] 8. Method for transmitting power from a generator (14) placed in a nacelle (4) of a wind turbine (2) as disclosed in the claims 1-7, characterized in at least the following steps of operation:
    a. let the generator (14) generate electric power
    b. convert the generated power to DC power by generator side converter (16)
    c. transmit the DC power by a power link (22) to TBU (Tower Bottom Unit) (20)
    d. convert the DC power by the grid side converter (18) into AC
    e. transmit the AC power generated by the grid side converter (18) to a grid.
    [9] 9. Method according to claim 8, characterized in that transmission of power is performed by superconducting conductors (30, 32), which conductors are cooled by cryogen cooling media (36).
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    同族专利:
    公开号 | 公开日
    DK179439B1|2018-08-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2018-08-21| PAT| Application published|Effective date: 20180705 |
    2018-08-22| PME| Patent granted|Effective date: 20180822 |
    优先权:
    申请号 | 申请日 | 专利标题
    DKPA201770003A|DK179439B1|2017-01-04|2017-01-04|Superconducting system for converter DC link|DKPA201770003A| DK179439B1|2017-01-04|2017-01-04|Superconducting system for converter DC link|
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