Abstract:
The invention concerns a module of a nacelle of a wind turbine, which is separately designed, manageable and comprise a housing part. The module is connectable to at least one further module of the nacelle, which is also separately designed, manageable and has a housing part, wherein the housing part of the module builds in the assembled status of the nacelle, which comprises several modules, a part of the housing of the nacelle. The invention concerns also a nacelle comprising several such modules, a wind turbine comprising such a nacelle as well as a method for the stepwise assembly of such a nacelle aloft.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefits of European application No. 0881259.4 filed Jan. 23, 2008 and U.S. Provisional application 60/989,467 filed Nov. 21, 2007, both of the applications are incorporated by reference herein in their entirety. 
       FIELD OF INVENTION 
       [0002]    The invention relates to a module of a nacelle of a wind turbine, a nacelle of a wind turbine, a wind turbine and a method for the assembly of a nacelle of a wind turbine. 
       BACKGROUND OF THE INVENTION 
       [0003]    Wind power becomes more and more important. Parallel with the increasing significance of wind power wind turbines are getting larger and larger, which makes it more difficult to transport the large, in general preassembled and integrated wind turbine parts from the place of manufacture to the sites of erection, this can be onshore or offshore. 
         [0004]    Normally a wind turbine comprises a few larger parts in form of the blades, the hub, the tower and the nacelle. Particularly the nacelle comprises a number of integrated main components such as a main shaft, a main bearing assembly, a gearbox, a generator, some power/control components, a transformer, a cooling system and so on, which are all arranged on a common bedplate and in a common nacelle housing. The bedplate has a yaw system to orient the nacelle towards the wind direction. Typically the nacelle is completely preassembled at the place of manufacture. 
         [0005]    When a wind turbine is erected the blades, the hub, the tower and the preassembled nacelle are transported to the site of erection. The tower is erected, the nacelle is mounted on the tower, the hub is mounted on the nacelle and the blades are attached to the hub by means of at least one crane. Thereby not only the transportation in particular the transportation of the large and heavy nacelle is difficult, but also the mounting on the tower, which requires sufficient crane capacity to handle the complete nacelle weight. 
         [0006]    Moreover the servicing of such a wind turbine is often very complicated and time consuming, in particular when one or more components of the nacelle have to be replaced. 
       SUMMARY OF INVENTION 
       [0007]    It is therefore an object of the present invention to lay the foundations that the transportation and/or the assembly of at least a part of a wind turbine is facilitated. It is a further object of the invention to indicate a method for the assembly of a part of a wind turbine. 
         [0008]    The first object is inventively achieved by a module of a nacelle of a wind turbine, which is separately designed, separately manageable and comprises a housing part, wherein the module is connectable to at least one further module of the nacelle, which is also separately designed, separately manageable and has a housing part, and wherein the housing part of the module builds in the assembled status of the nacelle, which comprises several modules, a part of the housing of the nacelle. Thus the invention pursues a modular concept or a modular design of a nacelle, wherein the single modules build in the assembled status substantially the nacelle and wherein preferably each module comprise at least one functional unit of a wind turbine, e.g. a generator, a transformer, a power unit, a control unit etc. Thereby the external housing part of the module forms a part of the external housing of the whole nacelle. Having the nacelle of a wind turbine divided into such separate modules it becomes possible to manufacture the modules at separate locations and to assemble the modules for forming a complete nacelle first during the installation of a wind turbine. This will facilitate not only the transportation of the modules, but also the specialization of manufacturing of certain modules at competence centres. Thereby a module is able to be transported or shipped completely, wherein in particular the housing part of the module provides mechanical and weather protection during transportation and storage of the module. 
         [0009]    Moreover it becomes easier to carry out the installation of the nacelle with limited crane capacity, since the assembly may be carried out at height, installing one module at a time, in which case the crane requirements are determined not by the complete nacelle weight but by the weight of the heaviest module. 
         [0010]    Furthermore in case of a failure of a complete module the respective module is able to be replaced. 
         [0011]    In a variant of the invention the module comprises connection means for connecting the module to at least a further module. Preferably the connection means of the module comprises at least one flange for connecting the module to the further module. Thus when a second module is arranged on a first module the flange of the second module and the flange of the first module, which are arranged oppositely to each other, are able to be bolted together. In such a way the nacelle is built stepwise until all required modules are arranged. 
         [0012]    According to a further variant of the invention the module comprises as functional unit a generator, a retaining arrangement, a cooling unit, a control unit, a transformer or a main-shaft-bearing arrangement. According to this variant of the invention there are different specialised modules in form of a generator module, a retaining arrangement module, a cooling module, a control module, a transformer module and a main-shaft-bearing arrangement module. 
         [0013]    In an embodiment of the invention the module comprises a substantially explosion and/or a fire resistant wall. In particular the transformer module comprises such an explosion and/or fire resistant wall next to a further module. Preferably the transformer or power-unit module is arranged on the rear end of the nacelle and comprise the mentioned explosion and/or fire resistant wall to the afore positioned module. According to a further embodiment of the invention a module, preferably the transformer or power-unit module comprises a bursting disc on its free end. In case of an explosion or a fire, the bursting disc, possibly being a part of the outer shell of the transformer or the power-unit module, will distort or be blown out to minimise blast effects in the nacelle and to protect the other modules and any personnel in the nacelle. In that situation the transformer or the power unit module is able to be replaced without replacing any other component. 
         [0014]    According to a further variant of the invention the module comprises at least one functional mechanical and/or functional electrical interface for connecting the module functionally to a further module. In that way the whole mechanical and electrical interconnection throughout the nacelle is able to be achieved. 
         [0015]    According to another embodiment of the invention the module and the housing part of the module respectively is self-supporting. So each module is able to be arranged on another module without the need of any supporting means for a module. 
         [0016]    The object of the invention is also achieved by a nacelle of a wind turbine comprising several separately designed, manageable and replaceable modules, wherein each module is connectable to at least one further module and has a housing part, wherein the modules build in the assembled status substantially the nacelle, and wherein the housing parts of the modules build at least partially the housing of the nacelle. Thereby all variants and advantages mentioned in relation with a single module apply also to the nacelle. 
         [0017]    According to a further variant of the invention at least one module comprises a helihoist platform. In this way it is possible to get to the nacelle by helicopter even under bad weather conditions. 
         [0018]    In an embodiment of the invention the nacelle comprises on its one end an end plate, which can be a bursting disc. 
         [0019]    The object of the invention is also achieved by a wind turbine comprising at least one module as disclosed before and/or a nacelle as disclosed before. 
         [0020]    The further object of the invention is achieved by a method for the assembly of a nacelle of a wind turbine as disclosed before, wherein modules as disclosed before are arranged in series on a wind turbine tower, wherein a module comprising a retaining arrangement or a main-shaft-bearing arrangement is arranged on the tower and at least one further module is arranged on the module comprising the retaining arrangement or the main-shaft-bearing arrangement. In this way the nacelle of a wind turbine is able to be assembled stepwise during the erection of the wind turbine on site with limited crane capacity. Thereby the modules are mounted one by one aloft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The invention will in the following be explained in more detail with reference to the schematic drawings, wherein 
           [0022]      FIG. 1  shows a nacelle comprising several single functional modules arranged on a tower of a wind turbine and 
           [0023]      FIG. 2  shows another embodiment of a nacelle comprising several single functional modules. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0024]      FIG. 1  shows schematically a nacelle  2  according to the invention arranged on tower  3  of an only partly shown wind turbine  1 . The nacelle  2  comprises several single, separately designed, separately manageable and separately replaceable modules  4 - 8  according to the invention. 
         [0025]    In case of the present embodiment of the invention a module  5  comprising a retaining arrangement in form of a retaining arm  9  is arranged on the tower  3 . More precisely the module  5  and the retaining arm  9  respectively is attached to a tower flange  10  and turnable around the axis A of the tower  3  by means of a not explicitly shown yaw system to orient the nacelle  2  towards the wind direction. The module  5  comprises a housing part  51 . In case of the present embodiment of the invention the housing part  51  is self-supporting and comprises on the front end and the rear end connection means in form of flanges  52 ,  53 . 
         [0026]    A self-supporting module  4  comprising a generator and a housing part  41  with a connection flange  42  on the rear end of the housing part  41  is arranged on the front end of the module  5 . Thereby the flange  42  of the housing part  41  and the flange  52  of the housing part  51  as well as a stationary part of the generator and the retaining arm  9  of the module  4  are bolted together. 
         [0027]    A conventional hub  13  is attached to the module  4  and a rotary part of the generator respectively by means of bolts. 
         [0028]    A self-supporting module  6 , comprising a cooling unit and a housing part  61  is arranged on the rear end of the module  5 . The housing part  61  of the module  6  comprises on the front end and the rear end connections means in form of flanges  62 ,  63 . The flange  53  of the housing part  51  of the module  5  and the flange  62  of the housing part  61  of the module  6  are bolted together, so that the module  6  is attached to the module  5 . 
         [0029]    A further self-supporting module  7  comprising a control unit and a housing part  71  is arranged on the rear end of the module  6 . The housing part  71  of the module  7  comprises on the front end and the rear end connections means in form of flanges  72 ,  73 . The flange  63  of the housing part  61  of the module  6  and the flange  72  of the housing part  71  of the module  7  are bolted together, so that the module  7  is attached to the module  6 . 
         [0030]    A last self-supporting module  8  comprising a transformer and a housing part  81  is arranged on the rear end of the module  7 . The housing part  81  of the module  8  comprises on the front end and the rear end connections means in form of flanges  82 ,  83 . The flange  73  of the housing part  71  of the module  7  and the flange  82  of the housing part  81  of the module  8  are bolted together, so that the module  8  is attached to the module  7 . 
         [0031]    In case of the present embodiment of the invention the transformer module  8  comprises additionally a substantially explosion and/or fire resistant wall  15  on the front side next to the module  7 . 
         [0032]    An end cap or end plate  14  is attached to the rear end of the module  8 . The end plate  14  closes the rear end of the module  8 . Thereby the end plate  14  is bolted with the flange  83 . In case of the present embodiment of the invention the endplate  14  is a bursting disc or a kind of bursting disc. Thus in case of explosion or fire in the transformer module  8  the bursting disc will distort or be blown out to minimise blast effects in the nacelle  2  and to protect the other functional modules  4 - 7  as well as any personal in the nacelle together with the explosion and/or fire resistant wall  15 . Because the transformer module  8  is the last module of the nacelle  2  it can be replaced in such a situation without replacing any other module or component of the wind turbine  1 . 
         [0033]    If necessary also the other modules are able to have an explosion and/or fire resistant wall and/or a bursting disc. 
         [0034]    As can be seen from  FIG. 1  the single, separately designed, manageable and replaceable modules  4 - 8  are arranged in series in relation to a centre axis B on the tower  3  of the wind turbine  1  and build in the assembled status the nacelle  2  of the wind turbine  1 . The housing parts of the single modules  4 - 8  are in such a way aligned to each other, that the single housing parts  41 ,  51 ,  61 ,  71  and  81  build together with the end plate  14  the housing or canopy of the nacelle  2 . Thus there is no separate or additional housing surrounding the single modules  4 - 8  necessary. In fact the housing parts  41 ,  51 ,  61 ,  71 ,  81  and the end plate  14  are connected with each other water tight, e.g. by means of appropriate sealings. 
         [0035]    All or some modules  4 - 8  can in a not shown manner comprise functional mechanical and/or functional electrical interfaces as wells as mechanical components and cables for mechanical and/or electrical interconnections of the modules  4 - 8 . There is e.g. a not shown electrical interconnection comprising functional electrical interfaces and cables between the generator module  4  and the transformer module  8 . Examples of functional mechanical interfaces of modules are the stationary part of the generator of the module  4  as a first functional mechanical interface and the retaining arm  9  of the module  5  as a second functional mechanical interface. 
         [0036]    A flange of a housing part preferably runs along the perimeter of the housing part, wherein the housing part is able to have a ring-shaped cross section or a cross section having a different form. 
         [0037]    The module  5  comprising the retaining arm  9 , which can also be identified as a load-bearing module, is carrying the weight and the load of the hub  13 , the not shown three rotor blades attached to the hub  13  and the modules  4 - 8 , thereby transferring the load to the tower  3 . 
         [0038]    As disclosed each module  4  - 8  can be self-supporting, wherein the housing part of each module typically is the weight- and load-carrying component of the respective module  4 - 8 . 
         [0039]    As already mentioned, having the nacelle  2  of the wind turbine  1  divided into the single modules  4 - 8  it becomes possible to manufacture the single modules  4 - 8  at separate locations and to assemble the modules  4 - 8  for forming a complete nacelle  2  first during the installation of the wind turbine  1 . This facilitates the transportation of the modules  4 - 8  to the site of erection as well as the specialization of manufacturing of certain modules at competence centres. Each module  4 - 8  is able to be transported or shipped completely, wherein in particular the housing part and an additional packaging of the module at both ends of the module provides mechanical and weather protection during transportation of the module. 
         [0040]    Further on in case of a failure of a complete module the respective module is able to be replaced. 
         [0041]      FIG. 2  shows another embodiment of a modularised nacelle  12  of a wind turbine  21  in an exploded view. 
         [0042]    In case of this embodiment a module  22  comprising a main shaft bearing arrangement or a load bearing arrangement including a main shaft  16  and two main bearings  17 ,  18  is arranged on a schematically shown tower  33 . A module  23  comprising a generator is arranged on the rear end of the module  22 , wherein the rotor of the generator is connected to the pivotable main shaft of the main shaft bearing arrangement. A hub  13  is attached to the main shaft  16  of the module  22 . 
         [0043]    A module  24  comprising a control unit is arranged on the module  23 , a module  25  comprising a cooling unit is arranged on the module  24  and a module  26  comprising a transformer is arranged on the module  25 . The transformer module  26  is closed with an end plate  27 . 
         [0044]    As can be seen from  FIG. 2  the nacelle  12  of a wind turbine can be modularised to such an extent that customised solutions are implemented simply by adding or deleting modules. The module  25  comprising a cooling unit can be e.g. an offshore cooling/climate control module  25   a  or a hot climate cooling module  25   b . Also the transformer module  26  is available in different designs, e.g. as standard transformer module  26   a  or as transformer module  26   b  with helihoist platform  28 . In the same way there can exist alternative designs concerning the other modules  22 - 24 . The connection of the modules  22 - 26  can be achieved as disclosed in the context with the embodiment of  FIG. 1 . The modules  22 - 26   b  have preferably substantially the same properties as the modules  4 - 8 .