GB2570462A

GB2570462A - Cabinet comprising heat pipes

Info

Publication number: GB2570462A
Application number: GB1801175.9A
Authority: GB
Inventors: Vetter Alf; Opie Ray
Original assignee: Moog Unna GmbH
Current assignee: Moog Unna GmbH
Priority date: 2018-01-24
Filing date: 2018-01-24
Publication date: 2019-07-31
Also published as: GB201801175D0

Abstract

A cabinet for electric components of a wind turbine comprises a housing structure 31 comprising a first wall 35 with an inner surface 35a configured to hold an electric component 41 in a mounting section 37. The first wall 35a comprises one or more grooves 61, 63, 65 recessed into the wall 35a, and extending away from the mounting section 37. A heat pipe 57, 58, 59 is mounted in the groove, and may be clamped in place by the electric component. The heat pipes may diverge from each other in a V-shape, and the remote ends of the heat pipes may be clamped by retaining members 73, 75, 77. A heat sink 80 is connected to an outer surface 35b of the first wall, opposite the inner surface 35a, at least opposite the one or more grooves 61, 63, 65.

Description

Technical Field

The present invention relates to a cabinet for electric components, particularly but not exclusively, to a cabinet for electric components of a wind turbine. Other aspects of the present invention relate to a wind turbine comprising the cabinet.

Background

Cabinets for electric components come in different shapes and sizes. With particular reference to wind turbines, such cabinets may include switch gears for controlling blade pitch actuators. Such blade pitch control switch gear cabinets house a variety of highpower electric components, such as insulated-gate bipolar transistors that combine high efficiency and fast switching.

It is a known problem that such electric components produce significant amounts of heat, which creates local hot spots that can cause failure of some or all of the electric equipment. To avoid excessive heat from being introduced into the electric components, existing cabinets are provided with heat sinks, such as cooling fins. These heat sinks generally increase the surface area in contact with the surrounding environment, and promote cooling of the electric components received within the cabinet.

With ever increasing demand on the performance of the electric components and shrinking package space availability, traditional heat sinks are often no longer sufficient to dissipate an amount of heat required to continuously operate modern electric components.

In view of the above, it is an object of the present invention to overcome the problems associated with the prior art. In particular, it is an object of the present invention to provide a cabinet for electric components, which exhibits increased heat dissipation characteristics and, at the same time, can be produced easily and cost effectively.

In a first aspect of the present invention, there is provided a cabinet for electric components according to independent claim 1. The cabinet comprises a housing structure for receiving electric components, the housing structure comprising a first wall with an inner surface configured to hold an electric component in a mounting section, said first wall comprising one or more grooves recessed from the first surface, said one or more grooves being arranged adjacent to and extending away from the mounting section. A heat sink is connected to an outer surface of the first wall, opposite the inner surface, the heat sink being arranged to at least cover an area of the outer surface opposite the one or more grooves. A heat pipe is located in each of the one or more grooves.

It will be understood that the present invention is not limited to cabinets with only one electric component; rather, a plurality of electric components may be received within the housing structure of the cabinet according to this invention. Naturally, however, some electric components will produce significantly larger amounts of heat than others, such that only the primary heat sources may require heat to be dissipated more quickly and effectively. In the cabinet of the present invention, such high-performing electric components (primary heat sources) will be attached to the mounting sections referred to in this specification. To this end, heat pipes are provided in one or more grooves, which are arranged adjacent to and extend away from the mounting section.

The skilled person will understand that heat pipes conduct heat much better than any solid metal conventionally used for the production of the housing structure. As such, heat pipes will act to remove heat from the mounting section and distribute the latter across a wider surface area of the housing structure. It should be understood, that unlike other prior art solutions, which utilise heat pipes to transport heat from the mounting section to a distant point of the housing, the present invention does not transfer the heat away from the mounting section towards a discreet point, which is arranged far away from the mounting section. Rather, the present invention aims to evenly distribute the heat generated by the electric component at the mounting section over large parts of the housing structure.

The aforementioned effect is achieved by arranging the heat sink as close as possible to the one or more grooves. In particular, the heat sink is arranged on an outer surface of a first wall, which is directly opposite to the inner surface on which the grooves are located. Consequently, heat transported away from the mounting section by means of the heat pipes is continuously dissipated along the entire length of the heat pipe due to the adjacent heat sink, rather than being transferred to and dissipated at an opposite end of the heat pipes. In other words, the heat pipes are arranged such that a larger area of the heat sink can be used to dissipate excess thermal energy.

In another embodiment, the cabinet comprises at least two grooves extending from the mounting section so as to form a substantial V-shape. According to this embodiment, the heat generated by the electric component attached to the mounting section is distributed in two directions, i.e. substantially across the entire first wall of the housing structure. Either of the two grooves forms one side of the V-shape.

The V-shaped grooves may be in close proximity at the mounting section, wherein the distances between the grooves gradually increases as the grooves extend away from the mounting section. This arrangement allows high amounts of thermal energy to be introduced into both heat pipes, even across a very small part of the housing structure. The concentrated heat energy is then distributed in two directions away from the mounting section.

According to yet another embodiment, the one or more grooves extend in a straight manner. Utilising straight grooves and reduces the cost of manufacturing and for the heat pipes located within the grooves. It will also help heat distribution along the heat pipes, and is particularly advantageous in combination with the V-shaped arrangement discussed hereinbefore. The heat pipes may have a tubular shape. However, any other shape, such as a flat shaped heat pipes, is also feasible.

The depth of the one or more grooves may be larger than 50% of a thickness of the first wall. In other words, the grooves may extend through more than 50% of the first wall, which will improve the transfer of heat between the heat pipes and the heat sink that is arranged on opposite sides of the first wall.

According to another embodiment, a heat conductive paste is provided between the heat pipe and an inner surface of the groove. Arranging heat conductive paste between the heat pipe and the inner surface of the groove will further improve the transfer of excess heat from the electric components attached to the mounting section towards and into the heat pipe. At the same time, the heat conductive paste will support heat dissipation from the heat pipe into the heat sink.

The heat sink may comprise a plurality of cooling fins. The cooling fins may extend in substantially the same direction as the one or more grooves. Arranging the cooling fins in the same direction as the grooves will aid in achieving an even distribution of the heat transported within the heat pipes. This is because the heat pipes will be distanced from the next cooling fin by the same amount along the entire length of the heat pipes.

According to another embodiment, the one or more heat pipes have a wick made from sintered metal powder. The sintered metal powder may be made of copper. The heat pipes may further comprise a working fluid made of water, ammonia, methanol, or ethanol.

According to another aspect of the present invention, there is provided a wind turbine comprising a rotating hub with one or more turbine blades and a cabinet for electric components described hereinbefore located within the hub.

In an embodiment, the one or more grooves extend along the first wall of the mounting section towards a first end, such that the first end of the grooves is arranged closer to the rotational axis of the hub than the mounting section. This particular arrangement of the grooves with respect to the rotational axis of the hub supports the functionality of the heat pipes. In particular, working fluid within the heat pipes flowing away from the mounting section is propelled naturally by the heat gradient between the mounting section and the cooler first end of the heat pipe. Working fluid vapour that condensates on the inside walls of the heat pipe is commonly effected by the capillary action of a wick. However, in the arrangement of this invention the flow of condensated working fluid back to the mounting section is effected or at least supported by the centrifugal forces caused due to the rotation of the hub during operation of the wind turbine. The centrifugal forces at least support the effect of the wick structure within the heat pipes. In some embodiments, it may even be feasible to remove the wick structure and return condensated working fluid to the mounting section by means of the centrifugal forces only.

The cabinet may be located within the hub such that the one or more grooves extend substantially in a radial direction, away from a rotational axis of the hub. In this embodiment, the rotational axis of the hub may be considered to be the origin of a rotational coordinate system. The grooves may extend in a radial direction away from this origin. This arrangement will further improve the effect of the centrifugal forces on the working fluid within the heat pipes.

In yet another embodiment, a blade pitch control assembly is mounted to the mounting section on the inner surface of the first wall. The blade pitch control assembly may be arranged to control a pitch actuator, which changes the angle of the blades with respect to the direction of the wind several times per minute. The blade pitch control assembly may be arranged to cover at least part of the one or more grooves. As such, the blade pitch control assembly may be used to fix the heat pipes within the grooves at least at the mounting section of the first wall.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

DETAILED DESCRIPTION

In the following detailed description, one or more embodiments will now be described by way of example only, with reference to the accompany drawings in which:

FIGURE 1 shows a schematic side view of an upper end portion of a wind turbine;

FIGURE 2 shows a top view of a cabinet according to an embodiment of the present invention;

FIGURE 3 shows a cross-section of the cabinet shown in Figure 2 along line 3-3;

FIGURE 4 shows a schematic heat distribution according to an embodiment of the present invention; and

FIGURE 5 shows a schematic cross-section of a wind turbine hub according to an embodiment of the wind turbine of the present invention.

Turning to Figure 1, there is shown a wind turbine, generally indicated at 1. A nacelle 11 of the wind turbine 1 is shown as being mounted on the upper marginal end portion of a tower 13. The nacelle 11 is rotatable mounted on the upper marginal end of the tower 13 for rotation about a vertical axis B. A hub 15 is mounted on the nacelle 11 for rotation about rotational axis A, which is substantially horizontal in Figure 1.

A plurality of blades, separately indicated at 20, are mounted on the hub 15 for rotation therewith. The pitch of each blade is independently controllable by means of an actuator assembly (not shown). A main shaft (not shown) transfers rotational movement of the hub into the nacelle to drive a generator 17 in the usual manner. The nacelle may also include various commonly known items, such as a gear box, transformers, and the like.

In order to control the movement of the blade pitch actuator assembly (not shown), a variety of electric components are required. In one example, the electric components may include one or more of motor controllers, power stages, position sensors, and processing units. In order to protect the electric control components from environmental influences, it is known to arrange them in one or more cabinets 30 within the hub 15. In the embodiment of Figure 1, two separate cabinets 30 are illustrated inside the hub. Of course, any number of cabinets 30 may be arranged within the cabinet. Each of the cabinets 30 may include electric control components configured to control the pitch actuator assembly of one turbine blade 20 only. As such, in the embodiment of Figure 1, one cabinet 30 may be provided per rotor blade 20. Alternatively, it is also feasible to provide a single cabinet, simultaneously controlling each of the pitch actuator assemblies.

Figure 2 shows a top view of an exemplary embodiment of the cabinet 30 of the present invention. To increase visibility, a top wall or cover of cabinet 30 is not illustrated. As shown, the cabinet 30 comprises a housing structure 31, which includes a variety of walls, such as side walls 33a, 33b, 33c and 33d. At the bottom end of the housing structure 31, a first wall 35 or floor structure is shown. In more detail, an inner surface 35a of the first wall 35 is illustrated in Figure 2 carrying two electric components.

A first electric component 41 is attached to a mounting section 37 of the housing structure 31. In this example, the first electric component 41 is bolted to the mounting section 37 of the first wall 35 on its inner surface 35a. To this end, the first wall may include a plurality of through holes or blind bores configured to receive fastening bolts of the first electric component 41.

In the example of Figure 2, the first electric component 41 represents a high-energy electric component, such as a motor controller comprising an insulated-gauge bipolar transistor (IBGT). As such, the first electric component 41 acts as a primary heat source, which during operation of the wind turbine introduces significant amounts of thermal energy into the housing structure 31 of the cabinet 30. Other electric components, such as second electric component 43 and third electric component 45 may also be provided within cabinet 30. For the purposes of this embodiment, the second and third electric components 43 and 45 may be considered as a secondary heat sources, which do not introduce significant amounts of thermal energy in comparison to the primary heat source. The third electric component 45 may be a printed circuit board, which is arranged on top of the first and second electric components 41, 43.

In order to more effectively distribute the heat generated by the primary heat source (i.e. the first electric component 41) across the entire surface of the first wall 35, one or more heat pipes are arranged within the first wall (or floor structure) 35. In the embodiment of Figure 2, three heat pipes 51, 53 and 55 are located in corresponding grooves 61, 63, 65. Each of the heat pipes has an end section 52, 54 and 56 located adjacent to the mounting section 37, that is, below the first electric component 41. The heat pipes 51, 53 and 55 extend from their respective end section 52, 54, 56 towards an opposite end section 57, 58, 59. The second end sections 57. 58 and 59 are located at a distance from the mounting section 37. As such, the grooves 61, 63 and 65 and their corresponding heat pipes 51, 53, 55 extend away from the mounting section 37 in at least one direction.

The heat pipes are fixated inside their corresponding groove 61, 63, 65 by means of mounting members 71, 73, 75 and 77. In the embodiment of Figure 2, the first electric component 41 simultaneously acts as the first mounting member 71 and covers the first end sections 52, 54 and 56 of each of the three heat pipes 51, 53, 55. On the opposite end of the heat pipes, that is, at the second end sections 57, 58 and 59, the heat pipes 51, 53, 55 are held in place by three individual mounting members 73, 75 and 77. It will be understood that at least the three mounting members 73, 75 and 77 may have any shape and/or size that provides sufficient support for the heat pipe 51, 53, 55.

Turning to Figure 3, there is shown a cross-section along line 3-3 of the cabinet 30 shown in Figure 2. In contrast to the illustration in Figure 2, the cross-section of Figure 3 additionally shows the top wall or cover 38 of the housing structure 31. The top wall 38 rests on the side walls 33a to 33d and may be removably connected thereto. An inner surface 38a of the top wall acts as an attachment region for a fourth electric component 47, such as another printed circuit board.

At the lower end of each side wall 33a to 33d, the first wall or floor structure 35 is located. The first wall 35 comprises an inner surface 35a, which acts as a mounting surface for one or more electric components, such as the first and second electric components 41, 43. The three grooves 61, 63 and 65 are recessed from the inner surface 35a of the first wall 35 and sized to receive corresponding heat pipes 51, 53, 55. A depth d of the three grooves 61, 63, and 65 is constructed to be more than 50% of a thickness D of the first wall 35. Since the heat pipes 51, 53, and 55 are sized to substantially fill the entire space of their corresponding grooves 61, 63 and 65, their diameter also exceeds 50% of the thickness D of the first wall 35. The remaining space between the inner surface of the grooves 61, 63, 65 and an outer surface of their corresponding heat pipes 51, 53, 55 is filled with a heat conductive paste.

On an outer surface 35b of the first wall 35, which is arranged opposite to the inner surface 35a, a heat sink 80, in the form of a plurality of cooling fins, is provided. As such, the cooling fins are arranged as close as possible to the heat pipes 51, 53, and 55 such that thermal energy transported from one end section of the heat pipes 51, 53, 55 to the opposite end section is continuously dissipated by the heat sink 80 along the entire length of the heat pipes 51, 53, 55. The combined effect of arranging the heat pipes within the wall 35 of the housing structure 31 that includes the heat sink 80 results in heat being evenly dissipated across the entire length of the heat pipes 51, 53 and 55, as schematically represented by Figure 4.

Figure 4 schematically shows how heat is transferred away from the first electric component 41 and spread across substantially all of the first wall 35. In more detail, each of the heat pipes 51, 53, 55 shows an elliptical heat distribution curve 91, 93 and 95. The heat pipes 51, 53 and 55 are arranged in a V-shaped pattern, such that the heat distribution curves 91, 93 and 95 cover a maximum area of the first wall 35, whilst overlapping as little as possible.

Turning to Figure 5, there is shown a schematic view of a hub, which is part of a wind turbine according to an embodiment of the present invention. The hub 15 shown in Figure 5 carries four rotor blades 20a, 20b, 20c and 20d. Of course, it is equivalently feasible to utilise any other number of rotary blades, particularly two or three blades, depending on the kind of wind turbine provided.

Each of the blades 20a to 20d is connected to a corresponding actuator assembly 90a, 90b, 90c and 90d for changing the pitch of each corresponding blade 20a to 20d with respect to the wind direction. The actuator assemblies 90a to 90d can be any kind of actuator assembly, such as electromechanical or electrohydraulic actuators. Each of the actuator assemblies 90a to 90d is controlled by a variety of electric components received within respective cabinets 30a, 30b, 30c, 30d of the present invention. As already mentioned hereinbefore, it is also feasible to control all of the actuator assemblies 90a to 90d with electric components received within a single cabinet of the present invention. In this example, each of the cabinets 30a to 30d includes a first electric component 41a, 41b, 41c and 41d, such as an IGBT motor controller, which acts as a primary heat source. During operation of such first electric component 41a to 41d, high-power electric energy is provided by the latter to its respective actuator assembly 90a to 90d, resulting in the generation of large amounts of thermal energy within the cabinets 30a to 30d, particularly at the respective mounting sections.

As described hereinbefore, so-created excess thermal energy is distributed across the first wall of each of the cabinets 30a to 30d by means of one or more heat pipes. As the working fluid within the heat pipes evaporates at a first end section, the hot gas is naturally urged towards the cooler second end section of the heat pipe. As the hot gas travels from the first to the second end section of the heat pipe, condensation occurs along the entire length of the heat pipe. As is well known in the art, this condensation process leads to dissipation of heat away from the heat pipes, thereby cooling the socondensated working fluid. The condensated working fluid is then transferred back to the first end section, i.e. towards the first electric component 41a to 41d / the mounting section, by means of a wick structure.

To support the return transport of the condensated working fluid, each of the cabinets 30a to 30d is arranged with respect to the rotational axis A of the hub 15 such that the centrifugal forces created due to rotation of the hub 15 force the condensated working fluid towards the first electric component 41a to 41d / the mounting section. This effect is achieved by arranging the second end portions of the heat pipes 51, 53 and 55 closer to the rotational axis A than the mounting section / the first electric component 41a to 41d.

Claims

1. Cabinet for electric components of a wind turbine, the cabinet comprising a housing structure for receiving electric components, the housing structure comprising a first wall with an inner surface configured to hold an electric component in a mounting section, said first wall comprising one or more grooves recessed from the first surface, said one or more grooves being arranged adjacent to and extending away from the mounting section;

a heat sink connected to an outer surface of the first wall, opposite the inner surface, the heat sink being arranged to at least cover an area of the outer surface opposite the one or more grooves;

a heat pipe located in each of the one or more grooves.

2. The cabinet of claim 1, wherein the cabinet comprises at least two grooves extending from the mounting section so as to form a substantial V-shape.

3. The cabinet of claim 2, wherein the grooves are in close proximity at the mounting section and wherein the distance between the grooves gradually increases as the grooves extend away from the mounting section.

4. The cabinet of any of claims 1 to 3, wherein the one or more grooves extend in a straight manner.

5. The cabinet of claims any of claims 1 to 4, wherein the heat pipe is has a tubular shape.

6. The cabinet of any of claims 1 to 5, wherein a depth of the one or more grooves is larger than 50% of a thickness of the first wall.

7. The cabinet of any of claims 1 to 6, wherein a heat conductive paste is provided between the heat pipe and an inner surface of the groove.

8. The cabinet of any of claims 1 to 7, wherein the heat pipe is arranged within the one or more grooves so as to not protrude over the inner surface of the first wall.

9. The cabinet of any of claims 1 to 8, wherein the heat sink comprises a plurality of cooling fins, the cooling fins preferably extending in substantially the same direction as the one or more grooves.

10. The cabinet of any of claims 1 to 9, wherein the heat pipe has a wick made from sintered metal powder, particularly copper powder.

11. The cabinet of any of claims 1 to 10, wherein the heat pipe comprises a working fluid made of water, ammonia, methanol, or ethanol.

12. A wind turbine comprising:

a rotating hub;

one or more turbine blades connected to the hub; and a cabinet of any of claims 1 to 11 located within the hub.

13. The wind turbine of claim 12, wherein the one or more grooves extend along the first wall from the mounting section towards a first end, such that the first end of the grooves is arranged closer to a rotational axis of the hub than the mounting section.

14. The wind turbine of claim 12 or 13, wherein a blade pitch control assembly is mounted to the mounting section on the inner surface of the first wall.

15. The wind turbine of claim 14, wherein the blade pitch control assembly is arranged to cover at least parts of the one or more grooves.