housing

Abstract

The present disclosure relates to a housing for an electrical device in a high voltage electric field, the housing comprising at least one top element and at least one corresponding bottom element extending circumferentially from a central portion, wherein the top and bottom elements are plate-like elements arranged substantially parallel to each other at a predetermined distance to provide a space therebetween. The top and bottom elements are each electrically connected at one end of the central portion and electrically contacted at a respective circumferential end to form at least a portion of the housing. The housing is at least partially constructed from an electrically conductive material. At least two slots are provided in the housing, the at least two slots extending from the central portion to the periphery to separate different portions of the housing.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a housing for electrical devices in high voltage electric fields. In particular, the present disclosure relates to a multifunctional shielded housing for wireless devices in high voltage environments. BACKGROUND

[0002] The use of wireless transmission of data and power in high voltage installations is increasing due to the introduction of more sensors and remote control systems. Often, this involves placing small devices containing electronics and wireless transmitters or receivers in very harsh electromagnetic environments. Some examples can include power transformers, substations and HVDC converter stations. In particular, too high electric fields can interfere with the electronics or cause partial discharges due to field enhancement at the surface of the inserted device. Therefore, some field grading and electrical shielding of the electronics is required. However, a full shielding cannot be expected, since wireless power transmission to the electronics is required when electric wires cannot be used in strong electric field environments. Therefore, the shielded housing must be permeable to the magnetic field used for power transmission. An additional problem is to design an antenna that allows high frequency data communication to and from the device. Placing the antenna elements outside the shielded housing will inevitably increase the risk of strong field enhancement and thus partial discharges. SUMMARY

[0003] Therefore, there is a need to fulfill at least one of the following requirements:

[0004] - Shielding of the external (e.g. 50 / 60 Hz) AC electric field efficiently, and at the same time minimizing the field enhancement just outside the housing.

[0005] - Allowing the externally applied magnetic field (e.g. typical frequencies in the MHz range) for wireless power transmission to reach the interior of the housing where the pick-up coils are placed.

[0006] - Having a design such that the housing itself can also be used as an antenna element for high frequency (e.g. GHz range) data communication.

[0007] The present disclosure relates to a housing.

[0008] Various exemplary embodiments of the housing disclosed herein relate to providing features that will become apparent when considered in connection with the following description and with reference to the following drawings. In accordance with various embodiments, exemplary systems, methods and apparatuses are disclosed herein. It should be understood, however, that these embodiments are presented by way of example and not limitation, and that various modifications can be made by those of ordinary skill in the art in the light of this disclosure, which is intended to be broadly applicable and should be construed to encompass all such modifications.

[0009] Accordingly, the present disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the particular order or hierarchy of steps in the methods disclosed herein are merely examples. The particular order or hierarchy of steps in the methods and processes disclosed herein can be re-arranged based on design. Accordingly, those of ordinary skill in the art will appreciate that the methods and techniques disclosed herein can be performed by other than the illustrated orders or hierarchies, without departing from the scope of the present disclosure. It is therefore intended that the disclosure be interpreted as including all variations that fall within the scope of the present disclosure.

[0010] The above and other aspects and implementations thereof are more fully described in the following detailed description along with the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 a perspective view showing an example of a housing according to the present disclosure,

[0012] Figure 2 a plan view showing an example of a housing according to the present disclosure, the housing comprising an antenna feed circuit,

[0013] Figure 3 a normalized electric field amplitude in an electric field in an exemplary housing according to the present disclosure is shown,

[0014] Figure 4 a normalized magnetic field component in an electric field in an exemplary housing according to the present disclosure is shown, and

[0015] Figures 5 to 7 radiation patterns in three respective planes of a housing according to Figure 2 are shown. DETAILED DESCRIPTION

[0016] In the following, exemplary embodiments of the present disclosure will be described. It should be noted that some aspects of any of the described embodiments can also be found in some other embodiments, unless otherwise stated or apparent. However, in order to improve the intelligibility, each aspect will only be described in detail at first mention and any repeated description of the same aspect will be omitted.

[0017] The present disclosure relates to a housing for an electrical device in a high voltage electric field, the housing comprising at least one top element and at least one corresponding bottom element extending circumferentially from a central portion, wherein the top element and the bottom element are plate-like elements, the top element and the bottom element being arranged substantially parallel to each other at a predetermined distance to provide a space therebetween. The top element and the bottom element are each electrically connected at one end of the central portion and electrically contacted at a respective circumferential end to form at least a part of the housing. The housing is at least partially composed of an electrically conductive material. At least two slots are provided in the housing, the at least two slots extending from the central portion to the periphery to separate different parts of the housing.

[0018] Various embodiments can particularly implement the following features.

[0019] The top element and the bottom element can be configured to be oriented in a direction substantially perpendicular to the electric field.

[0020] The housing can be configured to allow wireless power transmission to the space.

[0021] The housing can be split into two parts at the central part. The antenna feed circuit can be connected to the two parts of the housing.

[0022] The top element and the bottom element can be connected by a connecting part at the periphery of the top element and the bottom element. In particular, the top element, the bottom and the connecting part are integrally formed.

[0023] The slots can be symmetrically arranged with respect to the central part.

[0024] The top element and the bottom element forming the part of the housing can form a sector around the central part. The radius of the top element and the bottom element can in particular be between 5 mm and 75 mm. The distance between the top element and the bottom element can in particular be between 5 mm and 15 mm.

[0025] The top element, the bottom element and the connecting part can comprise a certain thickness and a certain electrical conductivity, respectively.

[0026] The space can be at least partially filled with a dielectric and insulating material.

[0027] An opening can be provided in the housing to enable insertion of an electronic device.

[0028] The housing can comprise an electrically conductive layer.

[0029] The width of the slots at the periphery of the housing can be less than 25% of the distance between the top element and the bottom element.

[0030] The distance between the slots at the periphery of the housing can be equal to or less than the distance between the top element and the bottom element.

[0031] The width of the slots can gradually increase from the central part towards the periphery.

[0032] In the following, it is assumed that the main direction of the AC electric field of a power transformer, a substation, an HVDC converter station, etc. is well known, so that the plane of the housing can be oriented substantially perpendicular to the electric field. In this way, the field enhancement at the surface of the housing will be minimized.

[0033] Figure 1An exemplary enclosure according to the present disclosure is shown. The enclosure 1 comprises at least one top element 2 and at least one corresponding bottom element 3 extending circumferentially from a central portion 6. The top element 2 and the bottom element 3 are plate-like elements which are arranged substantially parallel to each other at a predetermined distance to provide a space therebetween. The top element 2 and the bottom element 3 are each electrically connected at one end at the central portion 6 and electrically contacted at a respective circumferential end to form at least a portion of the enclosure 1. However, it is not required that the top element 2 and the bottom element 3 are in contact with each other at the central portion 6. In other words, there can be no direct connection between the top element 2 and the bottom element 3 at the central portion. The enclosure 1 is at least partially composed of an electrically conductive material. At least two slots 5 are provided in the enclosure 1, the aforementioned at least two slots extending from the central portion 6 to the periphery to separate different portions of the enclosure 1. In Figure 1 In particular, E0identifies the direction of the electric field. The overall shape of the enclosure 1 can be described as a flat cartridge shape.

[0034] The top element 2 and the bottom element 3 can be connected by a connecting portion 4 at the periphery of the top element 2 and the bottom element 3, respectively. The top element 2, the bottom element 3 and the connecting portion 4 can be integrally formed.

[0035] In other words, the enclosure 1 for an electrical device in a high voltage electric field can comprise a top element 2 and a bottom element 3 having a circular shape, wherein the top element 2 and the bottom element 3 are plate-like elements arranged parallel to each other. The top element 2 and the bottom element 3 can be connected by a connecting portion 4 at the periphery of the top element 2 and the bottom element 3, respectively, to provide a space therebetween and to form the enclosure 1. The enclosure 1 can be at least partially composed of an electrically conductive material and at least two slots 5 from the central portion 6 to the periphery can be provided in the enclosure 1 to form portions or segments of the enclosure 1, wherein the central portion 6 of the top element 2 and the bottom element 3 electrically connects these portions.

[0036] The overall shape of the enclosure 1 can in particular be curved or circular, such as an elliptical or circular shape, to avoid sharp corners having an adverse effect on the shielding performance.

[0037] In particular in use, the top element 2 and the bottom element 3 can be configured to be oriented substantially perpendicular to the direction of the electric field. Thereby, an electrical shielding of the space can be achieved. Further, the enclosure 1 can be configured to allow a wireless power transfer to the space inside the enclosure 1.

[0038] An electrical shielding of the interior space of the enclosure 1 is achieved even for other relative orientations of the enclosure 1 and the electric field. However, if they are not perpendicular to each other, a significant field enhancement can occur at the outer surface of the enclosure.

[0039] The top element 2, the bottom element 3 and the connecting portion 4 can comprise a certain thickness d and a certain electrical conductivity s, respectively, wherein the product of the thickness d and the electrical conductivity s is particularly less than 5 1 / Ω, i.e. 5 S. In principle, as long as the product s d is large enough, s d > 10 -9 S, the electric field decay inside the enclosure 1 (i.e. the Faraday cage effect) is not affected by the orientation. However, the field enhancement just outside the enclosure surface is affected by the aforementioned orientation. If this field enhancement is too large, this can result in partial discharges occurring there. By orienting the enclosure such that the external electric field is perpendicular to the flat surface of the enclosure, the field enhancement is minimized.

[0040] An opening can be provided in the enclosure 1 to enable insertion of an electronic device. The electronic device can for example be configured to provide operational data or control signals of a power transformer, a substation, an HVDC converter station, etc. to which the enclosure 1 is attached or in the vicinity of which the enclosure is located, or to provide operational data or control signals to the power transformer, the substation, the HVDC converter station, etc.

[0041] The enclosure 1 can be split into two parts at the central portion 6, as shown in Figure 2 The antenna feed circuit 7 can be connected to the two parts of the enclosure 1. In this way, the enclosure can additionally work as an antenna for communicating power transformer, substation, HVDC converter station, e.g. operational data or control signals from the electronic device via the enclosure 1.

[0042] Moreover, the presence of a gap in which the antenna feed circuit 7 is mounted (required to realize the GHz antenna function) as shown in Figure 2 requires that the flat surfaces of the top element 2 and the bottom element 3 are perpendicular to the electric field. For other orientations, a strong electric field can be present in the gap area.

[0043] The slots 5 can be provided symmetrically with respect to the central portion 6. The top element 2 and the bottom element 3 forming this part of the enclosure 1 can form a sector around the central portion 6. In examples, the radius of the top element 2 and the bottom element 3 is between 5 mm and 75 mm. Assuming the enclosure 1 is circular, its diameter can be between 10 mm and 150 mm. In examples, the distance between the top element 2 and the bottom element 3 is between 5 mm and 15 mm.

[0044] The space (i.e. the space between the top element 2 and the bottom element 3) can at least partially be filled with a dielectric and insulating material.

[0045] The enclosure 1 can comprise an electrically conductive layer. I.e. the enclosure 1 can be coated with an electrically conductive layer.

[0046] In an example, the width of the slots 5 at the periphery of the shell is less than 25% of the distance between the top element 2 and the bottom element 3. In an example, the distance between the slots 5 at the periphery of the shell is equal to or less than the distance between the top element 2 and the bottom element 3.

[0047] The width of the slots 5 can gradually increase from the central portion 6 towards the periphery.

[0048] Reference is made to Figure 1 and Figure 2 The exemplary shell 1 described will be explained in more detail with respect to the above mentioned requirements. The (cartridge shaped, i.e. circular) shell 1 forming the basis for the following simulations and calculations has a diameter of 100 mm and a thickness of 10 mm. In general, the diameter lies in the range of 10 mm to 150 mm and the thickness varies between 5 mm and 15 mm. The electronic device is positioned in the interior of the shell, which is filled with a dielectric and insulating material to provide mechanical support to the conductive shell layer. However, the nature of the above values and ranges is merely exemplary and the present disclosure is not limited thereto.

[0049] The following is about the electrical shielding of the interior. The low frequency electrical shielding of the interior can be achieved by using a Faraday cage type conductive shell 1. In Figure 1 the illustrated example shown in Fig. 1, the cage of the shell 1 consists of a thin conductive layer partially covering the surface of the shell 1. Here, the product of the layer conductivity s and thickness d has to be large enough to reduce the electric field level inside the shell 1 to an acceptable level. In general, s d should be larger than 10 -9 S (10 -9 1 / Ω ). Furthermore, the product s d should be smaller than 5 S (i.e. 5 1 / Ω ), in particular smaller than 1 S. Small layer surfaces (i.e. the central portion 6 close to the symmetry axis) electrically connect different parts of the shell 1 (i.e. the respective top element 2 and bottom element 3), which further improves the shielding against non-axial electric field components and provides a certain mechanical stability.

[0050] Figure 3 The shielding effect of the shell 1 is illustrated. In this simulation, an external electric field of E0= 1 V / m is assumed. Even with a relatively low value of the layer conductivity s, a significant shielding is obtained. It can also be seen that the shielding efficiency inside the shell 1 is not uniform. In particular, Figure 3 the graph of the electric field amplitude along two radial lines in the horizontal plane is shown, which are respectively underneath the conductive layer (i.e. between the top element 2 and the bottom element 3) and underneath the slots 5. In particular, the graph represents the normalized electric field amplitude (V / m) as a function of the radius r (m) underneath the slots (continuous line) and underneath the layer (i.e. the portion as explained above) (dashed line).

[0051] As can be seen from the diagram, the exemplary housing 1 provides a significant reduction in the electric field, particularly not only below these portions but also within the slot.

[0052] The following are the requirements for allowing a magnetic field to pass through and reach the space inside the casing 1 in order to provide wireless power transmission.

[0053] The efficiency of wireless power transmission can be optimized when: (i) the applied magnetic field is perpendicular to the plane of the pickup coil, and (ii) the area of ​​the planar pickup coil (e.g., in an electronic device placed inside housing 1 that requires power) is as large as possible. Both conditions are satisfied when the internal pickup coil is in the plane of housing 1 and the magnetic field is perpendicular to the same plane. In our case, this implies that optimized power transmission is achieved when the applied magnetic field is parallel to a strong external electric field.

[0054] However, due to the shielding effect of the induced current in the conductive outer shell layer, the amplitude of the magnetic field inside the shell will be reduced. Therefore, in order to achieve efficient power transmission, the generation of the induced current must be counteracted in some way. As described above, one way to accomplish this is to cut a slot 5 in the conductive outer shell layer 1. By orienting the slot 5 perpendicular everywhere to the original direction of the induced current, the amplitude of these currents and the damping of the magnetic field will be drastically reduced. In the case of the pillbox-shaped outer shell 1 without the slot, the induced current will circulate in an angular direction around the axis of symmetry of the shell (which is parallel to the applied magnetic field). Therefore, the radial slot 5 is introduced to impede the induced current and thus allow the magnetic field to penetrate the outer shell 1 (the small surface near the axis of symmetry, i.e., the central portion 6, will not have a significant effect). Figure 1 and Figure 2 The example design illustrates how such slots can be incorporated into the housing layer. Note that these slots do not disrupt the electrical connection between the upper and lower planar surfaces of housing 1. This is crucial for enabling electrical shielding to function as outlined above.

[0055] exist Figure 4 In the simulation shown, it is assumed that the imposed vertical magnetic field has an amplitude |H z |=1A / m and oscillates at a frequency of f=13MHz. Similarly, the product of layer thickness and conductivity is σd=5S. Figure 4 The vertical component of the magnetic field on the horizontal plane passing through the center of the outer shell 1 is shown along two radial lines. Figure 4 The diagram shows the normalized magnetic field over the radius, where the continuous line represents the magnetic field below slot 5, and the dashed line represents the magnetic field below the layers (i.e., these sections). The overall damping shows suitability for wireless power transmission.

[0056] The following are the requirements for providing antenna functionality. Since the outer shell 1 is conductive, it can be used as an antenna element. The simplest way to achieve this is to make it an electric dipole radiator. This is accomplished by the following steps: cutting the (pillbox-shaped) outer shell 1 into two halves at the central portion 6, and connecting these halves in the central portion 6 via the antenna feed circuit 7, as follows... Figure 2 As shown and explained above, this will produce a dipole antenna connected to feed circuit 7. For wavelengths longer than the size of housing 1 (i.e., the diameter in this example), the radiated power will be omnidirectional except in the direction close to the dipole moment. At shorter wavelengths, a significant direction dependence will occur.

[0057] It should be noted that the gaps created when the outer shell 1 is split have no effect on either the desired electrical shielding or magnetic field penetration.

[0058] In the examples above, such as Figure 2 As shown, two halves are created by cutting through the central portion 6. The antenna feed circuit 7 between the two halves is oriented along the y-direction, which also becomes the direction of the antenna dipole moment. Solving for the near field and then performing a near-field to far-field transformation produces... Figures 5 to 7 The radiation pattern is shown in the figure. Similarly, for the simulation, it is assumed that σd = 5S. The frequency is assumed to be 2.4 GHz. The quantities shown are the radiated power (in dB), i.e., the radiated power density varies as a function of direction. It is observed that the radiated power is distributed fairly uniformly, except along the direction of the antenna dipole moment (i.e., along the y-axis).

[0059] Figures 5 to 7 The radiated power is shown in the xy plane. Figure 5 ), xz plane ( Figure 6 ) and yz plane ( Figure 7 Two-dimensional diagrams in ).

[0060] According to this disclosure, it is possible to design a housing that strongly suppresses external electric fields while simultaneously allowing magnetic fields used for wireless power transmission to penetrate. Additionally, the housing can be used as an element of a dipole antenna for communication with external devices. With careful design, these three functions can be introduced without mutual interference. Therefore, the features and functions mentioned above can be combined in a compact design, the housing can be used across a wide frequency range, and a product that is very robust in terms of electrical, thermal, and mechanical properties can be provided.

[0061] While various embodiments of this disclosure have been described above, it should be understood that these embodiments are presented by way of example only and not by way of limitation. Similarly, various figures may depict exemplary architectures or configurations, which are provided to enable those skilled in the art to understand the exemplary features and functionality of this disclosure. However, such persons will understand that this disclosure is not limited to the illustrated exemplary architectures or configurations, but can be implemented using various alternative architectures and configurations. Additionally, as those skilled in the art will understand, one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of this disclosure should not be limited by any of the exemplary embodiments described above.

[0062] It should also be understood that any reference to elements in this document using names such as "first," "second," etc., generally does not restrict the number or order of those elements. Rather, these names may be used as a convenient means of distinguishing two or more elements or instances of elements. Therefore, referring to the first and second elements does not imply that only two elements can be used, or that the first element must somehow precede the second element.

[0063] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plural. A single unit can perform the function of several features recited in the claims. Terms such as "basically," "about," "approximately," etc., relating to properties or values, specifically define the properties or values ​​precisely, respectively. No reference numerals in the claims should be construed as limiting the scope.

Claims

1. A housing (1) for an electrical device in a high-voltage electric field, the housing (1) comprising: At least one top element (2) and at least one corresponding bottom element (3) extending circumferentially from the central portion (6), wherein the top element (2) and the bottom element (3) are plate-like elements, and the top element (2) and the bottom element (3) are arranged substantially parallel to each other at a predetermined distance to provide space therebetween. The top element (2) and the bottom element (3) are each electrically connected at one end of the central portion (6) and electrically contacted at their respective circumferential ends to form at least a portion of the housing (1); The outer shell (1) is at least partially made of a conductive material; and At least two slots (5) are provided in the housing (1), the at least two slots extending from the central portion (6) to the periphery to separate different parts of the housing (1).

2. The outer casing (1) according to claim 1, wherein, The top element (2) and the bottom element (3) are configured to be oriented in a direction substantially perpendicular to the electric field.

3. The outer casing (1) according to claim 1 or 2, wherein, The housing (1) is configured to allow wireless power transmission into the space.

4. The outer casing (1) according to claim 1 or 2, wherein, The outer shell (1) is divided into two parts at the central portion (6), and The antenna feed circuit is connected to two parts of the housing (1).

5. The outer casing (1) according to claim 1 or 2, wherein, The top element (2) and the bottom element (3) are connected by a connecting portion (4) at the periphery of the top element and the bottom element (3).

6. The outer casing (1) according to claim 5, wherein, The top element (2), the bottom element (3), and the connecting portion (4) are integrally formed.

7. The outer casing (1) according to claim 1 or 2, wherein, The groove (5) is arranged symmetrically with respect to the central portion (6).

8. The housing (1) according to claim 1 or 2, wherein, The top element (2) and the bottom element (3) that form part of the outer shell (1) form a fan shape around the central part (6).

9. The outer casing (1) according to claim 8, wherein, The radii of the top element (2) and the bottom element (3) are between 5 mm and 75 mm.

10. The outer casing (1) according to claim 8, wherein, The distance between the top element (2) and the bottom element (3) is between 5 mm and 15 mm.

11. The outer casing (1) according to claim 5, wherein, The top element (2), the bottom element (3), and the connecting portion (4) each have a certain thickness and a certain conductivity.

12. The outer casing (1) according to claim 1 or 2, wherein, The space is at least partially filled with dielectric and insulating materials.

13. The outer casing (1) according to claim 1 or 2, wherein, An opening is provided in the housing (1) to allow for the insertion of an electronic device.

14. The outer casing (1) according to claim 1 or 2, wherein, The outer casing (1) includes a conductive layer.

15. The housing (1) according to claim 1 or 2, wherein, The width of the groove (5) at the periphery of the housing is less than 25% of the distance between the top element (2) and the bottom element (3).

16. The housing (1) according to claim 1 or 2, wherein, The distance between the slots (5) around the periphery of the housing is equal to or less than the distance between the top element (2) and the bottom element (3).

17. The housing (1) according to claim 1 or 2, wherein, The width of the groove (5) gradually increases from the center portion (6) toward the periphery.

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