Nacelle for a wind turbine

Abstract

A wind turbine nacelle configured for mounting on a wind turbine tower and for supporting a rotor-supporting assembly, the nacelle comprising a main unit, and at least one auxiliary unit. The auxiliary unit accommodates a at least one component, e.g. a converter or transformer. To provide efficient transportation, lower costs and easier assembly, the operative component is suspended directly on the main unit.

Claims

1. A wind turbine nacelle configured for mounting on a wind turbine tower and housing a rotor-supporting assembly supporting a rotor, the nacelle further housing a power conversion assembly, the nacelle comprising: a main unit arranged to be connected to the wind turbine tower and housing the rotor-supporting assembly, and at least one auxiliary unit housing an operative component forming part of the power conversion assembly, wherein: the main unit and the auxiliary unit are separate units configured to be connected by a unit fixation structure at an interface, the operative component is suspended directly on the main unit, and the main unit and the at least one auxiliary unit are arranged side by side in a direction transverse to a rotational axis defined by the rotor-supporting assembly.

2. The nacelle according to claim 1, comprising a first suspension structure suspending the operative component directly on a main frame in the main unit, the main frame forming part of a load path from the rotor into the wind turbine tower.

3. The nacelle according to claim 1, comprising a second suspension structure for suspension of the operative component on the at least one auxiliary unit.

4. The nacelle according to claim 3, wherein the unit fixation structure is configured to fixate the at least one auxiliary unit to the main unit in an assembly position of the at least one auxiliary unit relative to the main unit, and wherein the first suspension structure is configured to take over suspension of the operative component from the second suspension structure upon movement of the at least one auxiliary unit to the assembly position.

5. The nacelle according to claim 2, wherein the first suspension structure comprises at least one bracket connected to the operative components and to the main frame.

6. The nacelle according to claim 5, wherein each bracket extends through a corresponding wall opening in an outer wall of at least one of the main unit and the auxiliary unit.

7. The nacelle according to claim 6, wherein each wall opening has a size exceeding a cross-sectional dimension of the corresponding bracket to define a gap between an edge about the wall opening and the bracket.

8. The nacelle according to claim 2, wherein the first suspension structure is configured for releasable suspension of the operative component to the main frame.

9. The nacelle according to claim 3, wherein the second suspension structure is configured for releasable suspension of the operative component on the at least one auxiliary unit.

10. The nacelle according to claim 1, wherein an interface between the main unit and the at least one auxiliary unit defines a gap allowing air to pass between a surface of the main unit and a facing surface of the at least one auxiliary unit.

11. The nacelle according to claim 10, wherein the first suspension structure extends across the gap.

12. The nacelle according to claim 1, wherein the operative component is an electrolysis cell stack, a transformer, or a converter.

13. The nacelle according to claim 1, wherein the rotor drives a generator located outside the nacelle.

14. The nacelle according to claim 1, wherein the nacelle further houses a generator driven by the rotor.

15. A method of assembling a wind turbine with the nacelle according to claim 1, comprising: receiving to a site of erection of the wind turbine, the main unit and the at least one auxiliary unit, the main unit including a main frame configured to form part of a load path from the rotor into the wind turbine tower, the at least one auxiliary unit including the operative component, attaching the at least one auxiliary unit to the main unit, and directly attaching the operative component in the at least one auxiliary unit to the main frame in the main unit.

16. The method according to claim 15, further comprising: supporting the operative component from the main frame via a first suspension structure, and supporting the operative component from the auxiliary unit via a second suspension structure.

17. The method according to claim 15, comprising transferring load from the second suspension structure to the first suspension structure while moving the auxiliary unit towards an assembly position wherein a unit fixation structure connects the auxiliary unit to the main unit.

18. The method according to claim 15, wherein the main unit is attached to the wind turbine tower, and the method further comprises: hoisting the at least one auxiliary unit to the main unit by use of a crane structure attached to the main unit, or lowering the at least one auxiliary unit from the main unit by use of the crane structure attached to the main unit.

19. The method according to claim 18, wherein hoisting the at least one auxiliary unit includes hoisting the at least one auxiliary unit only in a vertical plane by use of the crane structure.

20. A method of servicing a wind turbine with the nacelle according to claim 1, comprising: detaching the operative unit from the main unit while the operative unit is contained in the at least one auxiliary unit, and lowering the at least one auxiliary unit to a ground for service of replacement at the ground.

21. A wind turbine nacelle configured for mounting on a wind turbine tower and housing a rotor-supporting assembly supporting a rotor, the nacelle further housing a power conversion assembly, the nacelle comprising: a main unit configured to be connected to the wind turbine tower, wherein the main unit comprises at least one wall that defines an interior, and wherein the main unit includes a main frame and the rotor-supporting assembly in its interior, and wherein the main frame is configured to form part of a load path from the rotor into the wind turbine tower, and at least one auxiliary unit separate from the main unit and configured to be connected to the main unit by a unit fixation structure at an interface, wherein the at least one auxiliary unit comprises at least one wall that defines an interior, and wherein the at least one auxiliary unit includes an operative component forming part of the power conversion assembly in its interior, and a first suspension structure configured to extend from the interior of the main unit to the interior of the at least one auxiliary unit for suspending the operative component directly on a main frame in the main unit.

Description

LIST OF DRAWINGS

(1) In the following, embodiments of the disclosure will be described in further details with reference to the drawing in which:

(2) FIGS. 1a and 1b illustrate wind turbines;

(3) FIG. 2 illustrates the nacelle of the wind turbine;

(4) FIG. 3 illustrates a perspective view of the nacelle of FIG. 2;

(5) FIG. 4 illustrates the nacelle from FIG. 3 but seen from above;

(6) FIG. 5 illustrates an embodiment where the left and right-side auxiliary units contain identical components;

(7) FIG. 6 illustrates an embodiment where two auxiliary units 61, 62 are located one above the other;

(8) FIG. 7 illustrates schematically details of the interface;

(9) FIG. 8 illustrates the main unit and auxiliary unit from FIG. 7 after the auxiliary unit has been attached to the main unit;

(10) FIG. 9 illustrates an embodiment, where the first suspension structure is constituted by bolt shaped fixation pins;

(11) FIGS. 10, 11 illustrate in further details another embodiment of the first and second suspension structures;

(12) FIGS. 12-15 illustrate 4 different embodiments of interfaces between the main unit and the auxiliary unit.

(13) FIGS. 16-18 illustrate an embodiment where the main unit and auxiliary units are assembled by a hinge structure;

(14) FIGS. 19, 20 illustrate further details of a hook for attaching the auxiliary unit to the main unit;

(15) FIG. 21 illustrates the hook in an open position where the auxiliary unit is free to be lowered to the ground;

(16) FIG. 22 illustrates a cross section with two bolt holes for attachment of the auxiliary unit on the main unit;

(17) FIGS. 23, 24, 25 illustrate an embodiment where the hook is configured for sliding; and

(18) FIGS. 26-28 illustrate embodiments of cranes on the main unit for hoisting the auxiliary units.

DESCRIPTION OF EMBODIMENTS

(19) The detailed description and specific examples, while indicating embodiments, are given by way of illustration only, since various changes and modifications within the spirit and scope of this disclosure will become apparent to those skilled in the art from this detailed description.

(20) FIGS. 1a and 1b illustrate wind turbines 1 with a nacelle 2 mounted on a tower 3. A hub 4 carrying three rotor blades 5 forms a rotor and is carried by a rotor-supporting assembly in the nacelle 2. Typically, the rotor-supporting assembly comprises a rotor shaft connecting a gear arrangement and a generator to the hub. A gear is, however, not always required since the generator could be directly driven by the shaft. FIG. 1b illustrates a direct drive wind turbine with the generator 6 located outside the nacelle.

(21) FIG. 2 illustrates that the nacelle comprises a main unit 20 and two auxiliary units 21, 22. A cooling area 23 is arranged on top of the nacelle. The cooling area is formed by a heat exchanger which may form part of the main unit, and/or any of the auxiliary units. The main unit 20 is mounted on the tower 3 via a yawing arrangement (not shown), allowing the nacelle 2 to rotate in order to direct the rotor into the wind.

(22) FIG. 3 illustrates a perspective view of the nacelle 2 of FIG. 2. In FIG. 3 the outer walls of the nacelle 2 are (for the sake of explanation) transparent, thereby revealing the interior parts of the nacelle 2 and the wind turbine components accommodated therein. The main unit 20 accommodates a main bearing unit 31 supporting a main shaft for rotation therein, a gear arrangement 32 and a generator 33, arranged sequentially behind the hub 4, along a direction defined by the rotational axis of the hub 4. The components in the main unit primarily form part of the drivetrain.

(23) The auxiliary unit 22 accommodates a transformer unit 34, and a converter unit 35 which herein constitute two different operative components being accommodated in the auxiliary unit but carried by the main unit. In alternative embodiments, the operative component could be an electrolysis cell stack or a battery.

(24) Each auxiliary unit 21, 22 is mounted along a side of the main unit 20 by a unit fixation structure. In the disclosed embodiment, they are mounted in such a manner that one auxiliary unit 21 is mounted along a right side of the main unit 20 and the other auxiliary unit 22 is mounted along a left side of the main unit 20, as seen in a direction along a rotational axis of the hub 4 from the hub 4 towards a rear wall of the main unit 20.

(25) The main unit and the auxiliary units are enclosed and optionally sealable units such that one compartment is formed by the auxiliary unit, defining an auxiliary space and another compartment is formed by the main unit, defining a main space. That allows the drivetrain to be isolated from the converter and transformer. The two compartments may be joined by the cooperating openings 36 allowing personnel and equipment to enter from the main space in the main unit into the auxiliary space in the auxiliary unit. The openings 36 may be sealed and thereby prevent fire etc. from spreading from one of the main and auxiliary unit to the other one of the main and auxiliary unit.

(26) FIG. 4 illustrates a nacelle seen from above.

(27) FIG. 5 illustrates an embodiment where the left and right-side auxiliary units contain at least one identical component establishing a weight balance and a double function. The double function means that the wind turbine comprises two similarly functioning components, one contained in each of the auxiliary units. The components may be identical in nature and specification. In case of component failure of one unit, the wind turbine may continue operation on reduced power while the operative component in the other auxiliary unit is replaced.

(28) FIGS. 4 and 5 illustrate a transport system comprising a rail 42 extending from the main unit into the auxiliary unit and allowing easy handling of spare parts etc.

(29) In FIGS. 2-5, the auxiliary units are constituted by elements having generally the shape and size of standardised freight containers such as a 40 foot shipping freight containers having a dimension and structural specifications as provided by the ISO standard, ISO 668:2013 for series 1 freight containers. The auxiliary units are attached to the main unit by the ISO-corner lifting structure, typically moulded in steel and constituting a particularly strong interface to the container.

(30) FIG. 6 illustrates an embodiment where two auxiliary units 61, 62 are located one above the other. In this embodiment, the upper auxiliary unit 61 is constituted by a unit having the size and shape of a 40 foot shipping freight container, and the lower auxiliary unit 62 is constituted by a unit having the size and shape of a 20 foot shipping freight container. Both containers have a dimension and structural specifications as provided by the ISO standard, ISO 668:2013, and the auxiliary units are attached to each other mainly by the corner lifting arrangements of the 20 foot container, and partly by the corner lifting arrangement of the 40 foot container. Alternatively, both auxiliary units have the same length.

(31) FIG. 7 illustrates schematically details of the interface. The interface joins the auxiliary unit 71 and the main unit 72 in a releasable manner and allows the auxiliary unit to be attached to the main unit after transport to the installation site, or to be replaced e.g. during maintenance. In the disclosed embodiment, the auxiliary unit 71 is attached to the main unit 72 independently of any other units, and the unit fixation structure is constituted by an inward groove or track 73 in the main unit. The track 73 is illustrated with a dotted line and defines a recess into the outer surface 75. The track has a C-shaped profile in a horizontal cross section, i.e. when seen from above, the track is configured to receive the projection 74 provided on the auxiliary unit, and particularly it can receive the projection 74 through a procedure where the auxiliary unit 71 is lowered down along the outer surface 75 of the main unit 72. This is illustrated by the arrow 76. This procedure allows easy replacement of an auxiliary unit and the operative component accommodated therein without detachment of the other auxiliary unit and the operative component accommodated therein.

(32) The main unit may form a load path from the operative component, which is housed in the auxiliary unit, down into the tower, e.g. via the main frame. Particularly, this load path may be different from the load path from the auxiliary unit into the tower. In the following, this is explained relative to different embodiments.

(33) The auxiliary unit 71 accommodates a converter 77 which is fixed to the auxiliary unit by the second suspension structure constituted by the bolt shaped fixation pins 78.

(34) The main unit has a strengthening bracket 79 attached to the outer wall and configured for receiving the weight of the converter 77 when the auxiliary unit is received and fixed on the main unit.

(35) FIG. 8 illustrates the main unit and auxiliary unit from FIG. 7 after the auxiliary unit has been attached to the main unit. In this state, the bolt shaped fixation pins 78 are extended sideways to the left and thereby engage into the strengthening bracket feature 79. The bracket may be connected to a rigid frame in the main unit, e.g. supported by the main frame to thereby direct loads from the operative component directly into the tower via the main frame.

(36) The bolt shaped fixation pins now constitute the first suspension structure by which the converter is carried directly by the main unit. The first suspension structure forms part of a load path from the operative component into the tower, and the interface between the main unit and the auxiliary unit forms part of another load path from the auxiliary unit into the tower.

(37) In the illustrated embodiment of FIGS. 7-8, the first and second suspension structures are both constituted by the same set of bolts which extend from the converter and into one or both of either the auxiliary unit or main unit.

(38) FIG. 9 illustrates an embodiment, where the first suspension structure is constituted by bolt shaped fixation pins and the second suspension structure is constituted by support legs 91 between a bottom of the converter and the bottom of the auxiliary unit.

(39) FIG. 10 illustrates in further details another embodiment of the first and second suspension structures. In this embodiment, the main unit 101 and the auxiliary unit 102 are joined by the unit fixation structure constituted by the corner lifting points 103 of the container which constitutes the auxiliary unit 102.

(40) The transformer 104 is carried by the first suspension structure, here in the form of a support frame 105 resting on the bottom of the auxiliary unit 102 and it is suspended directly on the main frame 106 inside the main unit 101. The main frame thereby forms part of the load path for the operative component into the tower.

(41) At least 50 percent of the weight of the transformer 104 is thereby carried by the main unit 101 and the remaining weight is carried by the auxiliary unit 102, which is again carried by the main unit 101. That remaining part of the weight is thereby not carried directly by the main unit 101.

(42) FIG. 11 illustrates an embodiment comparable to the embodiment in FIG. 10 but where the suspension structure 105 comprises the support frame 105 suspended via a bracket structure comprising lower brackets 1101 and upper brackets 1102 which is placed on the main frame 106 inside the main unit 101. The main frame thereby forms a load path for the operative component into the tower.

(43) FIGS. 12-15 illustrate four different embodiments of the unit fixation structure forming the interfaces between the main unit and the auxiliary unit. In each of these four illustrations, the main unit 121 and the auxiliary unit 122 are connected by cooperating structures forming the unit fixation structure and being described in further details below.

(44) In FIG. 12, the cooperating structures are constituted by brackets 123 by which the main and auxiliary units are joined by bolts.

(45) In FIG. 13, the cooperating structures are constituted by a lower bracket 123 like the one used in FIG. 12. At the upper edge, the main unit and auxiliary unit are assembled by a hook 131 pivotally joined to the main unit at the hinge point 132. The hook can rotate as indicated by the arrow 133 and engages the edge-bracket 134 of the auxiliary unit when in the illustrated position. When the lower bracket 123 is removed, and the hook 131 is rotated into the main unit, the auxiliary unit can be lowered to the ground.

(46) The embodiment in FIG. 14 is comparable to the embodiment in FIG. 13, but where the lower bracket is replaced with an upper bracket 141, and the hook is placed at a lower edge.

(47) In FIG. 15, a lower and an upper bracket is used for bolting the auxiliary unit to the main unit, and a slidable support 151 supports the lower surface of the auxiliary unit while the bolts are attached. If it is desired to lower the auxiliary unit to the ground, e.g. for replacement or maintenance of the operative component, the slidable support can be slid to the left and the auxiliary unit can be lowered down, e.g. by use of a crane build into the main unit.

(48) In any of the embodiments shown in FIGS. 12-15, the brackets or hooks direct the load from the auxiliary unit into a rigid part of the main unit, e.g. into load carrying column e.g. a corner column of the main unit. Various structural features may connect the brackets or hooks which carry the auxiliary unit directly to the main frame in the main unit to thereby establish a load path into the tower.

(49) In addition to the hook and bracket unit fixation structure illustrated in FIGS. 12-15, a first suspension structure (not shown) connects an operative component (not shown) directly to the main frame inside the main unit.

(50) FIGS. 16-18 illustrate an embodiment of the unit fixation structure where the main unit and auxiliary units are assembled by a hinge structure comprising hinge elements 163, 164, 165 with a hole for receiving a hinge pin 166 extending through the hinge elements. FIG. 16 further shows that the interface forms a gap 167 allowing air to pass e.g. from beneath the nacelle to above the nacelle, through the gap. The gap is held open at the bottom by the distance element 168, which could be constituted by a number of pins or an open structure allowing air to pass between the units.

(51) Such a gap may increase thermal convection and thus cooling of the space inside the main and auxiliary units. The gap is not limited to the embodiment with the hinge structure but could be combined with any other assembly method. The first suspension structure may extend across the gap.

(52) FIGS. 17 and 18 illustrate the hinge elements 163, 164, 165 and the hinge pin 166. In FIG. 17, the hinge elements are positioned correctly relative to the each other such that the hinge pin can be slid into the hinge elements. In FIG. 18, the hinge pin is inserted through the holes of the hinge elements.

(53) FIGS. 19a, 19b and 19c illustrates further details of the unit fixation structure in the form of a hook for attaching the auxiliary unit 191 to the main unit 192. The hook 193 is suspended rotationally at the hinge 194 in the main unit. The hook can rotate through the opening 195 in the auxiliary unit and catch a recess or edge 196 in the auxiliary unit.

(54) The hook could also be attached in the auxiliary unit and catch a recess or edge in the main unit, in which case it may be attached reversely, i.e. as illustrated in FIG. 20. The position of the hook may be controlled by an actuator.

(55) FIG. 21 illustrates the hook in an open position where the auxiliary unit is free to be lowered to the ground.

(56) FIG. 22 illustrates a cross section where two bolt holes 221 can be seen. The bolt holes facilitate attachment of the auxiliary unit on the main unit by use of bolts for solid fixation. In this embodiment, the hook is mainly for positioning the auxiliary unit in the correct height relative to the main unit, and the bolts are for joining the units.

(57) In FIGS. 19, 21 and 22, the hook is preferably supported by the main frame of the main unit, e.g. via column or support posts arranged along an inner surface of the main unit. In FIG. 19, the column 197 extends along an inner surface of the main unit and supports the hook on the main frame in the bottom part of the main unit.

(58) In FIG. 20, where the hook forms part of the auxiliary unit, the edge in the main unit where the hook engages, may preferably be carried by the main frame in the main unit. Again, this could be via posts or columns arranged along an inner surface of the main unit.

(59) The hook could be moved between the open position (FIG. 21) and the closed position (FIG. 19, 20, 22) by power driven means, e.g. including a hydraulically driven actuator.

(60) FIGS. 23, 24, 25 illustrate an embodiment where the hook is not rotationally suspended but slidingly suspended. The function is like the embodiment of FIGS. 19-22. In FIGS. 23 and 24, a cross sectional view illustrates a bolt hole 231 which can be used for solid, bolted fixation of the auxiliary unit on the main unit. The hook in FIG. 23 is attached to the main unit and the hook in FIG. 24 is attached to the auxiliary unit.

(61) In FIG. 25a, the hook 251 is slided to the left thereby disengaging the edge of the auxiliary unit and allowing the auxiliary unit to be lowered to the ground. In FIG. 25b, the hook 251 is slided to the right, thereby engaging the edge of the auxiliary unit and holding the two units fixed to each other. The hook may be slided by power driven means, e.g. by a hydraulic actuator.

(62) In the description above, FIGS. 19-25 are explained as parts of the unit fixation structure for fixing the auxiliary unit to the main unit. Similar structures may constitute the first suspension structure by which the operative component is releasably fixed to the main unit.

(63) Similar structures may also constitute the second suspension structure by which the operative component is releasably fixed to the auxiliary unit, and similar structures may constitute the third fixation structure by which two auxiliary units are fixed to each other.

(64) FIG. 26 illustrates hoisting of an auxiliary unit up or down during maintenance or replacement. The auxiliary unit is hoisted by use of a crane 261 forming part of the main unit. Movement is essentially only in the vertical plane, illustrated by the arrow 263, and the attachment of the auxiliary unit on the main unit may be facilitated by a unit fixation structure as described previously, including movable fixation features such as hinged or slidable hooks etc.

(65) FIG. 27 illustrates the internal crane 261 in an enlarged view. The crane is attached to a roof part of the main unit and by its location, it can hoist the auxiliary unit in a vertical direction to a position where said unit fixation structures can form engagement between the main and the auxiliary units. This procedure may not require movement in other directions than the vertical direction and therefore facilitates a simple assembly procedure with reduced need for external crane assistance. For adjustment in a horizontal plane, the crane 261 may have the option of moving horizontally, e.g. as illustrated by the arrow 262.

(66) FIG. 28 illustrates schematically, another crane structure with a double cantilever beam 281 on the roof of the main unit 282. The cantilever beam 281 can extend sideways in telescopic section 283. The cantilever beam facilitates lifting and connection of the auxiliary unit 284 to the main unit 282. Even though the unit fixation structures disclosed herein, including pivotable or slidable hooks, generally facilitate attachment of the auxiliary unit by hoisting only in the vertical direction, the in and out movement facilitates fine adjustment of a horizontal distance between the main unit and the auxiliary unit.

Definitions

(67) Herein, the term nacelle means the generally accepted term describing the machine house for a wind turbine, i.e. that part which carries the rotor and drivetrain, and which is carried by the wind turbine tower.

(68) The terms main unit and auxiliary unit herein refers to units which can be transported separately, and which can be assembled with one or more other units to form the nacelle.

(69) Herein, the term rotor-supporting assembly refers to those parts of the nacelle which carries the rotor, typically a drivetrain, a main bearing and a main frame. The drivetrain may include different components depending on the type of wind turbine, e.g. a rotor shaft, the generator, and optionally a gearbox between the rotor shaft and the generator.