WO2006069570A1

WO2006069570A1 - Multi-functional plate

Info

Publication number: WO2006069570A1
Application number: PCT/DK2004/000925
Authority: WO
Inventors: Jørgen Jessen MØLLER; Einer Lykke Iversen; Thomas Morthorst Jensen
Original assignee: Danfoss Drives A/S
Priority date: 2004-12-29
Filing date: 2004-12-29
Publication date: 2006-07-06

Abstract

The present invention relates to a multi-functional plate member for mounting in an electronic device, the multi-functional plate member comprising a base plate and means for holding at least one electrical connector adapted for interconnecting electronic circuits or components positioned within the electronic device, the holding means being arranged on a surface part of the base plate. The base plate comprises an amount of electrically conducting particles sufficient to form a shield against EMC. The base plate further has a non-planar surface structure in order for the base plate to ensure a predetermined air circulation within the electronic device. The present invention further relates to a frequency converter applying a multi-functional plate.

Description

MULTI-FUNCTIONAL PLATE

The present invention relates to a multi-functional plate adapted to be mounted in a closed housing of an electronic device, such as in a frequency converter. In particular, the present invention relates to a multi-functional plate having a plurality of properties such as electrical properties, shape etc. The present invention further relates to an electronic device comprising a multi-functional plate.

BACKGROUND OF THE INVENTION

In order for minimise the risk of overheating electronic devices cooling arrangements are often provided. Such cooling arrangement may be as simple as providing cooling fins to the relevant electronic circuits or components. These cooling fins can be arranged either inside or outside the electronic device.

In case the cooling fins are arranged on the outside of the electronic device the circulation of natural air is in most cases sufficient to cool the cooling fins and thereby cool the electronic circuit or component to be cooled. In case the cooling fins are arranged inside the electronic device cooling fans are often required in order to ensure a sufficient flow of air around the cooling fins. To ensure that a sufficient amount of air is guided to each of the cooling fins a fan would most likely be required for each of the cooling fins. An arrangement having a plurality of cooling fins with associated cooling fans is a costly arrangement. For the same reason a more cost effective solution is required.

It is an object of the present invention to provide a multi-functional plate having a plurality of properties, such as predetermined electrical and mechanical properties, flow characteristics etc.

It is a further object of the present invention to provide a multi-functional plate being capable of replacing other components, such as such as cooling fans, so as to obtain a cost effective solution.

SUMMARY OF THE INVENTION

The above-mentioned objects are complied with by providing, in a first aspect, a multifunctional plate member for mounting in an electronic device having a substantially closed housing, the multi-functional plate member comprising - a base plate,

- means for holding at least one electrical conductor adapted for interconnecting electronic circuits or components positioned within the housing of the electronic device, the holding means being arranged on a surface part of the base plate,

wherein the base plate comprises air circulation means to ensure a predetermined air circulation within the housing of the electronic device.

The air circulating means may comprise one or more though-going openings in the base plate and/or one or more detached air guiding members (air guides) arranged on one or more surface parts of the base plate. The one or more detached air guiding members may be integrated with the base plate, or alternatively, they may be separated arrangements that are mounted on the base plate.

Alternatively or in addition, the base plate may be formed as a non-planar surface structure. By non-planar surface structure is meant that the base plate may be constituted by a plurality of substantially planar surface structures angled relative to each other. For example, a base plate may be constituted by two parallel planar surface structures and one intermediate planar surface structure interconnecting the two parallel planar surface structures wherein the intermediate planar surface structure is arranged at an angle relative to the two parallel planar surface structures. The given example is by no means limiting in terms of the number of surface structures and the arrangements of these surface structures relative to each other. The base plate may be formed as a one-piece component.

Electrically conducting particles may optionally be embedded into the base plate material in order to obtain certain EMC properties. The electrically insulating base plate material may be a polymer-based material, such as for example plastic.

The holding means may be implemented as grooves or indentations arranged on one or more surface parts of the base plate. Alternatively or in addition, the holding means may be arranged as detached projections provided on one or more surface parts of the base plate.

The multi-functional plate member according to the first aspect of the present invention may further comprise at least one electrical conductor for interconnecting electronic circuits or components positioned within the housing of the electronic device. The at least one conductor may be formed as a copper wire or copper plate part having a rectangular cross-section. Other materials such as brass and aluminium are, however, also applicable. Since the positioning of the at least one conductor is well-defined the EMC properties of the plate member with electrical conductor may be adjusted in a controllable manner. Similarly, the well-defined position of the at least one conductor on the base plate is important seen from safety prospective in that the base plate is capable of keeping the low and high voltage components, such as circuits and cables, away from each other whereby unintended short circuiting may be avoided.

The multi-functional plate member according to the first aspect of the present invention may further comprise an arrangement for securing a fan to the base plate, the fan being adapted to generate an air flow within the housing of the electronic device.

In a second aspect, the present invention relates to a frequency converter comprising a multi-functional plate member according to the first aspect of the present invention. The frequency converter may further comprise a substantially closed housing for encapsulating the electronic circuits or components constituting the frequency converter. Cooling of the electronic circuits or components constituting the frequency converter may be provided by circulating the air contained within the substantially closed housing by use of a fan. The fan may be positioned inside the housing, or alternatively, outside the housing. In the latter example, a small opening could be made in the housing so that the externally mounted fan may generate a negative pressure inside the housing whereby an air flow is generated inside the housing. The negative pressure inside the housing is provided by generating an air flow, on the outside of the housing, across the opening in the housing.

The degree of encapsulation is for example given by the IP-scale, where IP 55 is a completely closed encapsulation, IP 21 is an encapsulation level that can withstand falling water droplets, and IP 00 is a device having no encapsulation. By substantially closed is meant an encapsulation level corresponding to at least IP 21.

In a third aspect, the present invention relates to an electronic device having a substantially closed housing and comprising electronic circuits or components and a multi-functional plate member positioned within the substantially closed housing, the multi-functional plate member comprising

- a base plate,

- at least one electrical conductor adapted for interconnecting the electronic circuits or components in the electronic device, the at least one electrical conductor being arranged on a surface part of the base plate, wherein the base plate comprises air circulation means to ensure a predetermined air circulation within the housing of the electronic device.

The air circulating means may comprise one or more though-going openings in the base plate and/or one or more detached air guiding members arranged on one or more surface parts of the base plate. The electronic circuits or components may comprise a rectifier circuit, an intermediate circuit and a converter circuit.

BRIEF DESCRIPTION OF THE INVENTION

The present invention will now be explained with reference to the accompanying figures, wherein

Fig. 1 shows a top-view of a first embodiment of the present invention,

Fig. 2 shows the first embodiment of the present invention from below,

Fig. 3 shows an enlarged top-view of the first embodiment of the present invention,

Fig. 4 shows a top-view of the first embodiment wherein a fan and air guiding means have been mounted on the base plate,

Fig. 5 shows the embodiment of Fig. 4 seen from another angle,

Fig. 6 shows an enlarged view of the area of the base plate wherein the fan has been mounted,

Fig. 7 shows an enlarged view of the area of the base plate wherein the air guiding means has been mounted, and

Fig. 8 shows a second embodiment of the present invention, the second embodiment is illustrated from below.

While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a first embodiment of the present invention. As seen, the base plate 1 of this first embodiment is constituted by three parts 2, 3, and 4, and a cover 5 that may be flipped onto planar part 4. The cover 5 is kept in place by the fixation means 6a, 6b, 7a, and 7b, and access to part 4 is provided through holes 8 and 9. The parts 2, 3, 4 and 5 normally constitute a one-piece component of an electrically isolating material, such as for example plastic.

The embodiment shown in Figure 1 is constituted of two substantially planar parts 2 and 4, and an intermediate part 3 which is angled relative to parts 2 and 4. The intermediate part 3 is equipped with air guiding means 10 and 11 formed as through-going openings. These openings allow air to circulate around the various components constituting the electronic device in which the plate is mounted. The embodiment shown in Figure 1 also comprises a region 12 adapted to house a fan for circulating the air inside the device. The fan (which is shown in Figure 5) will be mounted between the uprights 13a and 13b. In addition, the embodiment shown in Figure 1 comprises a number of channels 14 for accommodating and guiding electrical conductors for interconnecting components or devices of the electronic device. As seen, each of the channels 14 has at least one end portion 15a. Other channels have end portions 16a and 16b at both ends. The embodiment shown in Figure 1 further comprises supports 18 and 19 adapted to hold additional air guides. The embodiment of Figure 1 is seen from the back side in Figure 2.

Figure 3 shows an enlarged portion of the bottom part of Figure 1 wherein electrical conductors leaves the plate for being connected to external components or circuits inside the device. The channels 14 and an end portion 15a are shown in Figure 3. The conductors accommodated in the channels are kept in place by the protrusion 17 which prevents that the conductor leaves the channels which may cause electrical short-circuiting of components, circuits or devices inside the device. In order to have an effective protection each of the channels 14 has a protrusion 17 arranged on one of its side-walls near the edge 20 of the plate.

Figure 4 shows the embodiment of Figure 1 with electrical conductors 21, 23a, and 23b and additional air guides 22 and 24 mounted on the plate. Furthermore, a fan 25 has been mounted on the plate. The air guide 22 comprises an opening 26 aligned with the opening 11 of the plate. By having this arrangement air is allowed to be guided from the upper side of plate region 2 to the lower side of the plate region 4, or vice versa. In Figure 4 the air guides 22 and 24 constitute separate component mounted on the plate. Alternatively, the air guides 22 and 24 could as well be integrated with the plate so that the plate and the air guides 22 and 24 constitute a one-piece component of a polymer-based material, such as for example plastic.

In Figure 4 electrical conductors are arranged in the channels 14. Electrical conductors 21 are adapted to establish electrical connections to electrical devices or components external to the plate, whereas electrical conductors 23a and 23b interconnect electrical devices or components positioned within the area covered by the plate. By having the electrical conductors 21, 23a and 23b positioned in the channels the position of these conductors are well defined which is an advantage of the plate according to the present invention. As seen in Figure 4 and 5 (which shows the embodiments of Figure 4 from another angle) cable shoes are mounted on the ends of the electrical conductors. The cable shoes fit into the channels ends 15a, 16a and 16b - see Figure 1. In Figure 4 and 5 the fan 25 will generate a primary air flow on the left side of air guide 24. This primary air flow cause secondary air flows to be generated across other regions of the plate - for example across the right side of the plate. Figure 6 shows an enlarged illustration of the region accommodating the fan 25. As seen, the fan 25 is mounted and kept in position between uprights 13a and 13b.

Figure 7 shows an enlarged view of a second embodiment of the present invention. Again, channels 26a and 26b with no electrical conductors mounted therein, and channels 27a, 27b and 27c with electrical conductors mounted therein are depicted. Furthermore, the embodiment shown in Figure 7 shows three spacers 28a, 28b, and 28c. These spacers ensure that the electrical connectors in channels 26a and 26b are not short-circuited by an electrically conducting element, such as a wire or another kind of electrical conductor, crossing channels 26a and 26b. The spacers simple prevent that a conducting element comes in electrical contact with the wires/conductors in channels 26a and 26b. The spacers may also ensure that a high-voltage part and a low-voltage part of for example a frequency converter, may be kept electrically isolated.

A bottom view of the embodiment shown in Figure 7 is shown in Figure 8. It should be noted that the edges 29 of part 30 of the plate will form a waterproof interface with a corresponding edge of a housing of an electronic module (not shown). In case of a frequency converter, this electronic module could involve a set of coils forming part of an intermediate circuit of the frequency converter. The cover 31 is adapted to be flipped onto the part 30, and access is provided through the holes 32 and 33. When the multi-functional plate is mounted in an electronic device, such as a frequency converter, is serves to ensure that a generated air flow is properly circulated within the housing of the electronic device. The air circulation is, as already mentioned, assisted by openings and/or air guides arranged in/on the plate. The air flow is generated by one or more fans mounted in the housing of the electronic device. Optionally the one or more fans can be arranged on the plate. The plate may also provide electrical isolation between circuit boards of the electronic device. For example, the plate may be sandwiched between two stacked circuit boards. Other arrangements of the plate in order to obtain a predetermined electrical isolation level between circuits, devices or components constituting for example a frequency converter may also be obtained.

Claims

1. A multi-functional plate (1) member for mounting in an electronic device having a substantially closed housing, the multi-functional plate member comprising

- a base plate,

- means (14) for holding at least one electrical conductor (21, 23a, 23b) adapted for interconnecting electronic circuits or components positioned within the housing of the electronic device, the holding means being arranged on a surface part of the base plate,

wherein the base plate comprises air circulation means (11, 22, 24) to ensure a predetermined air circulation within the housing of the electronic device.

2. A multi-functional plate member according to claim 1, wherein the air circulating means comprises one or more though-going openings (11) in the base plate and/or one or more detached air guiding members (22, 24) arranged on one or more surface parts of the base plate.

3. A multi-functional plate member according to claim 1 or 2, wherein the base plate is fabricated in a polymer-based material, such as plastic.

4. A multi-functional plate member according to any of claims 1-3, wherein the holding means (14) are implemented as grooves or indentations arranged on one or more surface parts of the base plate.

5. A multi-functional plate member according to any of claims 1-4, wherein the holding means (14) are arranged as detached projections provided on one or more surface parts of the base plate.

6. A multi-functional plate member according to any of the preceding claims, further comprising at least one electrical conductor (22, 23a, 23b).

7. A multi-functional plate member according to any of the preceding claims, further comprising an arrangement (13a, 13b) for securing a fan (25) to the base plate, the fan being adapted to generate an air flow within the housing of the electronic device.

8. A multi-functional plate member according to any of the preceding claims, wherein the base plate is constituted by sections of substantially plane surface parts.

9. A multi-functional plate member according to any of the preceding claims, wherein the base plate is formed as a one-piece component.

10. A frequency converter comprising a multi-functional plate member according to any of the preceding claims.

11. A frequency converter according to claim 10, further comprising a substantially closed housing for encapsulating the electronic circuits or components constituting the frequency converter.

12. A frequency converter according to claim 11, further comprising one or more fans for cooling the electronic circuits or components constituting the frequency converter by circulating the air contained within the substantially closed housing.

13. A frequency converter according to claim 12, wherein at least one of the one or more fans is positioned within the substantially closed housing.

14. An electronic device having a substantially closed housing and comprising electronic circuits or components and a multi-functional plate member positioned within the substantially closed housing, the multi-functional plate member comprising

- a base plate,

- at least one electrical conductor adapted for interconnecting the electronic circuits or components in the electronic device, the at least one electrical conductor being arranged on a surface part of the base plate,

15. An electronic device according to claim 14, wherein the air circulating means comprises one or more though-going openings in the base plate and/or one or more detached air guiding members arranged on one or more surface parts of the base plate.

16. An electronic device according to claim 14 or 15, wherein the electronic circuits or components comprise a rectifier circuit, an intermediate circuit and a converter circuit.