阅读说明：本技术 具有降低的噪声振动的多电极功率电容器 (Multi-electrode power capacitor with reduced noise vibration ) 是由 F·班达洛 于 2018-04-25 设计创作，主要内容包括：本公开涉及一种功率电容器,包括：外壳；第一套管；第二套管或接地螺栓,具有与外壳相同的电势,其中第一套管和第二套管穿过外壳延伸；介电液体；以及多个卷绕式电容器元件(9),每个卷绕式电容器元件(9)包括：第一电极(11),包括导电材料的两个第一层(11a、11b),该两个第一层被连接到第一套管,两个第一层被布置为能够朝向彼此和远离彼此移动；第二电极(13),包括导电材料的两个第二层(13a、13b),该两个第二层被连接到第二套管或接地螺栓,两个第二层被布置为能够朝向彼此和远离彼此移动；以及介电层,被布置在第一电极与第二电极之间；其中两个第一层(11a、11b)、两个第二层(13a、13b)以及介电层(15)被一起卷绕至多个匝中,以获得第一电极(11)、所述第二电极(13)、以及介电层(15)的多个层,其中卷绕式电容器元件(9)在外壳中以堆叠的方式被布置,相邻的卷绕式电容器元件彼此直接接触,以及其中电容器元件被沉浸在介电液体中。(The present disclosure relates to a power capacitor, comprising: a housing; a first sleeve; a second bushing or ground bolt having the same electrical potential as the housing, wherein the first bushing and the second bushing extend through the housing; a dielectric liquid; and a plurality of coiled capacitor elements (9), each coiled capacitor element (9) comprising: a first electrode (11) comprising two first layers (11a, 11b) of electrically conductive material, the two first layers being connected to the first sleeve, the two first layers being arranged to be movable towards and away from each other; a second electrode (13) comprising two second layers (13a, 13b) of electrically conductive material connected to a second bushing or earth bolt, the two second layers being arranged to be movable towards and away from each other; and a dielectric layer disposed between the first electrode and the second electrode; wherein two first layers (11a, 11b), two second layers (13a, 13b) and a dielectric layer (15) are wound together into a plurality of turns to obtain a plurality of layers of a first electrode (11), said second electrode (13) and a dielectric layer (15), wherein the coiled capacitor elements (9) are arranged in a stacked manner in a housing, adjacent coiled capacitor elements are in direct contact with each other, and wherein the capacitor elements are immersed in a dielectric liquid.)

1. A power capacitor (1) comprising:

A housing (3);

A first sleeve (5);

A second bushing (7) or earth bolt having the same potential as the housing (3),

Wherein the first sleeve (5) and the second sleeve (7) extend through the housing (3);

A dielectric liquid; and

a plurality of coiled capacitor elements (9), each coiled capacitor element (9) comprising:

A first electrode (11) comprising two first layers (11a, 11b) of electrically conductive material connected to the first sleeve (5), the two first layers being arranged to be movable towards and away from each other;

A second electrode (13) comprising two second layers (13a, 13b) of electrically conductive material connected to the second bushing (7) or to the earth bolt, the two second layers (13a, 13b) being arranged to be movable towards and away from each other; and

A dielectric layer (15) arranged between the first electrode (11) and the second electrode (13);

Wherein the two first layers (11a, 11b), the two second layers (13a, 13b) and the dielectric layer (15) are wound together into a plurality of turns to obtain a plurality of layers of the first electrode (11), the second electrode (13) and the dielectric layer (15),

Wherein the coiled capacitor elements (9) are arranged in a stacked manner in the housing (3), adjacent coiled capacitor elements (9) being in direct contact with each other, wherein the capacitor elements (9) are immersed in the dielectric liquid.

2. The power capacitor (1) as claimed in claim 1, wherein the two first layers (11a, 11b) have the same layer thickness.

3. Power capacitor (1) according to claim 1 or 2, wherein the two second layers (13a, 13b) have the same layer thickness.

4. A power capacitor (1) according to any of the preceding claims, wherein each of the two first layers (11a, 11b) is a conductive foil.

5. A power capacitor (1) according to any of claims 1-3, wherein each of the two first layers (11a, 11b) is a metallization layer provided on a respective side of the film.

6. a power capacitor (1) according to any of the preceding claims, wherein each of the two second layers (13a, 13b) is a conductive foil.

7. the power capacitor (1) according to claims 1 to 3 and 5, wherein each of the two second layers (13a, 13b) is a metallization layer provided on a respective side of the film.

8. A power capacitor (1) as claimed in any one of the preceding claims, wherein the first electrode (11) comprises exactly two first layers (11a, 11b) of electrically conductive material.

9. power capacitor (1) according to any of the preceding claims, wherein the second electrode (13) comprises exactly two second layers (13a, 13b) of electrically conductive material.

10. Power capacitor (1) according to any of the preceding claims, wherein the capacitor element (9) is flattened.

11. a power capacitor (1) according to any of the preceding claims, wherein for each capacitor element each of the two first layers consists of a respective single first continuous layer and each of the two second layers consists of a respective single second continuous layer.

12. A power capacitor (1) according to claim 11, wherein each of the two first layers and each of the two second layers extend along a majority of the axial length of the capacitor element.

13. A power capacitor (1) according to claim 12, wherein each of the two first layers extends from a first axial end of the capacitor element towards an opposite second axial end of the capacitor element, terminating before reaching the second axial end, and wherein each of the two second layers extends from the second axial end towards the first axial end, terminating before reaching the first axial end.

14. Power capacitor (1) according to any of the preceding claims, wherein the dielectric layer (15) is arranged between the first electrode (11) and the second electrode (13), wherein the first electrode (11), the dielectric layer (15) and the second electrode (13) are arranged parallel to each other in a sandwich configuration.

15. A power capacitor (1) according to any of the preceding claims, wherein, for each capacitor element, when the first electrode (11) has a positive or negative potential, a first layer (11a) of the first electrode (11) is attracted to one (13b) of the second layers (13a, 13b) arranged on opposite sides of the dielectric layer (15), and another (13a) of the second layers (13a, 13b) of the second electrode arranged adjacent to the one second layer (13b) and the one second layer (13b) repel each other.

16. A power capacitor (1) as claimed in claim 15, wherein for each capacitor element the two first layers (11a, 11b) repel each other when the first electrode (11) has a positive or negative potential.

Technical Field

The present disclosure relates generally to power capacitors. The present disclosure relates particularly to a power capacitor that provides vibration attenuation.

Background

The power capacitor may include a plurality of capacitor elements electrically connected in parallel and electrically connected in series. As depicted in fig. 1a, each such capacitor element comprises two electrode layers 19 and 21 and an intermediate dielectric layer 23. The dielectric layer 23 is thus arranged between the two electrode layers 19 and 21. The dielectric layer 23 may comprise, for example, a polymer material. The capacitor element is wound such that a large number of turns consisting of two electrode layers and dielectric layers is obtained. The capacitor elements may be arranged in a stacked manner, forming an active package inside the power capacitor case or housing. Inside the housing, the active package is immersed in a liquid that is permeable to the polymer material.

In fig. 1a, the capacitor element is shown during a zero crossing (i.e. when the voltage applied across the two electrodes 19 and 21 is zero). As shown in fig. 1b, when a voltage is applied to the two electrodes 19 and 21 of the power capacitor, an attractive force (coulomb force) is generated across the dielectric layer 23 between the two electrodes 19 and 21 because the two electrodes have different potentials. This attractive force, indicated by the arrow 17 and the arrow between the electrode layers, acts simultaneously on each turn of the power capacitor. This force will deform the soft dielectric material between the electrodes. The total deformation of the active package is the sum of the deformations across all turns of all capacitor elements. As shown in fig. 1c, the attractive force will become zero when the voltage crosses the next zero crossing. When the voltage potential is reversed, the charge on electrode 19 and electrode 21 will change polarity, but the same attractive force will appear again, as shown in fig. 1 d. This causes mechanical movement between the electrode layers, causing the electrode layers to oscillate at twice the frequency of the applied alternating voltage. Since the stack of capacitor elements is immersed in the liquid, the vibrations of the capacitor elements are transferred to the housing of the capacitor. Surface vibrations of the housing will generate undesirable sound in the form of audible noise.

An example of a power capacitor with noise reduction capability is disclosed in EP 0701263B 1. The power capacitor includes at least two capacitor elements consisting of electrodes separated by one or more dielectrics. The capacitor elements are arranged in rows to form a capacitor package. At least one spring element is arranged between pairs of adjacent capacitor elements in the row or is fixed at one end of the row outside the capacitor elements. The stiffness of the spring element is adjusted such that external vibrations of the capacitor are reduced. This results in reduced sound radiation from the capacitor.

WO2014202446 discloses a capacitor device having a plurality of capacitor elements arranged in a row or in a stack. Each capacitor element has two electrodes and a dielectric material disposed between the electrodes. Between each pair of adjacent capacitor elements there is a damping element for damping vibrations caused by the electrodes.

The spring element and the damping element in the prior art occupy space inside the housing of the power capacitor and do not contribute to the capacitance of the power capacitor.

disclosure of Invention

In view of the above, it is an object of the present disclosure to provide a power capacitor which solves or at least alleviates the problems of the prior art.

Accordingly, there is provided a power capacitor comprising: a housing; a first sleeve; a second bushing or ground bolt having the same electrical potential as the housing, wherein the first bushing and the second bushing extend through the housing; a dielectric liquid; and a plurality of coiled capacitor elements, each coiled capacitor element comprising: a first electrode comprising two first layers of electrically conductive material, the two first layers being connected to the first sleeve, the two first layers being arranged to be movable towards and away from each other; a second electrode comprising two second layers of electrically conductive material, the two second layers being connected to a second bushing or ground bolt, the two second layers being arranged to be movable towards and away from each other; and a dielectric layer disposed between the first electrode and the second electrode; wherein the two first layers, the two second layers and the dielectric layer are wound together in a plurality of turns to obtain a plurality of layers of the first electrode, a plurality of layers of the second electrode and a plurality of layers of the dielectric layer, wherein the coiled capacitor elements are arranged in a stacked manner in the housing, adjacent coiled capacitor elements are in direct contact with each other, and wherein the capacitor elements are immersed in the dielectric liquid.

A damping of the oscillation of the first and second electrodes may thus be obtained. In particular, this may be obtained by an electrode configuration, wherein each of the first and second electrodes comprises two different layers of electrically conductive material extending parallel to each other turn by turn (turn by turn). The first and second electrodes will still be attracted through the dielectric, but will cancel out the electrode motion as the voltages alternate due to the repulsion of the two layers of each electrode at the same voltage potential. The vibrations will thus be substantially cancelled and thus a damping of the sound can be obtained.

Thus, attenuation of sound is obtained only by the double-layer configuration of the first electrode and the double-layer configuration of the second electrode.

According to one embodiment, the two first layers have the same layer thickness.

By providing two first layers of conductive material having the same thickness, a better cancellation of vibrations can be obtained.

according to one embodiment, the two second layers have the same layer thickness.

By providing two second layers of conductive material having the same thickness, a better cancellation of vibrations can be obtained.

According to one embodiment, each of the two first layers is a conductive foil.

The two first layers of the conductive foil are arranged in a stacked manner and are wound together with the two second layers and the dielectric layer.

Each conductive foil may for example be made of aluminum.

According to one example, each conductive foil may include a zinc alloy.

The conductive foil can advantageously be made very thin so that its total thickness corresponds to the thickness of a standard electrode foil of a power capacitor.

according to one embodiment, each of the two first layers is a metallization layer disposed on a respective side of the film. To this end, the first electrode may comprise a double metallised film. Each of the metallized films defines a respective one of the two first layers of conductive material of the first electrode. The membrane may be, for example, a suitable soft polymer membrane.

This metallization to obtain the two first layers of conductive material may be obtained by, for example, electroplating, spraying or Physical Vapor Deposition (PVD).

According to one embodiment, each of the two second layers is a conductive foil.

Each conductive foil may for example be made of aluminum.

According to one example, each conductive foil may include a zinc alloy.

The conductive foil can advantageously be made very thin so that its total thickness corresponds to the thickness of a standard electrode foil of a power capacitor.

According to one embodiment, each of the two second layers is a metallization layer disposed on a respective side of the film. To this end, the second electrode may comprise a double metallised film. Each of the metallized films defines a respective one of the two second layers of conductive material of the second electrode. The membrane may be, for example, a suitable soft polymer membrane.

This metallization to obtain two second layers of conductive material may be obtained by, for example, electroplating, spraying or PVD.

According to one embodiment, the first electrode comprises exactly two first layers of electrically conductive material. The first electrode thus consists of two first layers of electrically conductive material.

According to one embodiment, the second electrode comprises exactly two second layers of electrically conductive material. The second electrode thus consists of two second layers of electrically conductive material.

The use of only two first layers of electrically conductive material is advantageous, because in this way the canceling effect of the vibrations can be obtained, while at the same time the material costs and the size of the wound capacitor element can be kept low. The additional layer of conductive material does not contribute to the capacitance of the power capacitor and therefore exactly two first layers and exactly two second layers are considered to be optimal to achieve maximum sound attenuation of the power capacitor with minimum capacitance per volume loss of the power capacitor.

according to one embodiment, the capacitor element is flattened.

a flattened capacitor element means that the wound capacitor element has been compressed. The initially cylindrical roller (roll) of the capacitor element has been radially compressed into an oval or rectangular shape. The cross-section of the capacitor element thus has an oval or rectangular shape. There will be one minor axis and one major axis in the cross-section of the capacitor element.

With the flattened structure, the capacitor element occupies less space in the housing, and the energy density of the power capacitor is increased.

The problem of vibrations occurring in capacitor elements can be particularly problematic in flattened capacitor elements, since flattened capacitor elements are not rotationally symmetrical like cylindrical capacitor elements.

According to one embodiment, for each capacitor element, each of the two first layers consists of a respective single first continuous layer, and each of the two second layers consists of a respective single second continuous layer.

According to one embodiment, each of the two first layers and each of the two second layers extend along a majority of an axial length of the capacitor element.

According to one embodiment, each of the two first layers extends from a first axial end of the capacitor element towards an opposite second axial end of the capacitor element, terminating before reaching the second axial end, and wherein each of the two second layers extends from the second axial end towards the first axial end, terminating before reaching the first axial end.

According to an embodiment, the dielectric layer is arranged between the first electrode and the second electrode, wherein the first electrode, the dielectric layer and the second electrode are arranged parallel to each other in a sandwich configuration.

According to one embodiment, for each capacitor element, when the first electrode has a positive or negative potential, the first layer of the first electrode is attracted to one of the second layers arranged on opposite sides of the dielectric layer, and the other of the second layers of the second electrode arranged adjacent to the one second layer and the one second layer repel each other.

According to one embodiment, the two first layers repel each other when the first electrode has a positive or negative potential for each capacitor element.

In any direction perpendicular to the central axis of the capacitor element, at any axial point where the first and second electrodes overlap turn by turn, when one of the two electrodes has a positive potential and the other electrode has a negative potential, the two first layers will repel each other and the two second layers will repel each other. Furthermore, the first and second electrodes will attract each other. Thus, in any of the perpendicular directions there will be an alternating attractive and repulsive configuration between pairs of adjacent first/second layers of electrodes.

According to one example, each capacitor element may comprise a single dielectric sheet or film, forming a dielectric layer between the first and second electrodes.

According to one example, the first electrode is directly connected to the first bushing. The first electrode is thus in mechanical contact with the first sleeve.

According to one example, the second electrode is directly connected to the second bushing or the grounding bolt. The second electrode is thus in mechanical contact with the second bushing or the grounding bolt.

In general, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to a/an/the element, device, component, part, etc. are to be interpreted openly as referring to at least one instance of the element, device, component, part, etc., unless explicitly stated otherwise.

Drawings

Specific embodiments of the inventive concept will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1a to 1d schematically illustrate the generation of vibrations in a prior art power capacitor;

Fig. 2 shows a perspective view of an example of a power capacitor;

Fig. 3 shows a wound capacitor element; and

Fig. 4a to 4d show simplified cross-sectional views of a wound capacitor element in four stages during an ac voltage duty cycle.

Detailed Description

the present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like reference numerals refer to like elements throughout the specification.

Fig. 2 shows an example of the power capacitor 1. The power capacitor 1 comprises a housing, can or casing 3, a first bushing 5 and a second bushing 7.

As an alternative to the second bushing, the power capacitor may be provided with a grounding bolt. In this case, the earth bolt typically has the same potential as the housing.

A first cannula 5 passes through the housing 3. Thus, the first cannula 5 extends through the housing 3.

The second sleeve 7 passes through the housing 3. Thus, the second sleeve 7 extends through the housing 3.

The power capacitor 1 further comprises a plurality of wound capacitor elements 9. The coiled capacitor elements 9 are arranged in a stacked manner. The coiled capacitor elements 9 are arranged in direct contact with each other. Therefore, adjacent coiled capacitor elements 9 are in direct mechanical contact.

The coiled capacitor elements 9 are electrically connected to each other. The coiled capacitor elements 9 may for example be connected in series and/or in parallel. As will be described in detail below, each wound capacitor element 9 is electrically connected to the first sleeve 5 and the second sleeve 7. As an alternative to being electrically connected to the second bushing, each wound capacitor element may instead be electrically connected to a grounding bolt.

The power capacitor 1 comprises a dielectric liquid. The dielectric liquid may be, for example, an oil or an ester. The stacked coiled capacitor elements 9 are immersed in a dielectric liquid. The dielectric liquid thus penetrates the dielectric material to improve its performance and to fill all cavities or empty spaces inside the housing 3.

Referring to fig. 3, an example of a wound capacitor element 9 is shown. Each wound capacitor element 9 comprises a first electrode 11 and a second electrode 13.

The first electrode 11 comprises two first layers 11a and 11b of electrically conductive material. The two first layers 11a and 11b of the first electrode 11 are arranged in a stacked configuration. The two first layers 11a and 11b are arranged parallel to each other for each turn of the coiled capacitor element 9. The first electrode 11 may advantageously comprise exactly two first layers 11a and 11 b. In addition, the first electrode may comprise more than two first layers of conductive material.

Both first layers 11a and 11b are electrically connected to the first sleeve 5. Therefore, the two first layers 11a and 11b have the same potential. The two first layers 11a and 11b are configured to be movable toward and away from each other in a wound state of the wound capacitor element 9. As will be described in more detail below, this possible movement between the two first layers 11a and 11b provides vibration damping.

According to an example, the first electrode 11 may comprise two conductive foils arranged to extend parallel to each other. The two conductive foils form a respective one of two first layers 11a and 11b of conductive material. The conductive foil is advantageously made as thin as possible so that its total thickness is substantially the same as the thickness of a conventional foil electrode. Alternatively, the first electrode 11 may comprise a double metallised film. In this case, each metallized surface of the double metallized film forms a respective one of the two first layers 11a and 11 b. The thickness dimension of the film is compressible and allows the two metallized surfaces to move toward or away from each other when the coiled capacitor element is energized.

as shown for the example in fig. 3, the second electrode 13 comprises two second layers 13a and 13b of electrically conductive material. The two second layers 13a and 13b of the second electrode 13 are arranged in a stacked configuration. The two second layers 13a and 13b are arranged parallel to each other for each turn of the coiled capacitor element 9. The second electrode 13 may advantageously comprise exactly two first layers 13a and 13 b. In addition, the first electrode may comprise more than two first layers of conductive material.

Both second layers 13a and 13b are electrically connected to the second sleeve 7. Alternatively, the two second layers may be electrically connected to the grounding bolt. Therefore, the two second layers 13a and 13b have the same potential. The two second layers 13a and 13b are configured to be movable toward and away from each other in a wound state of the wound capacitor element 9. This possible movement between the two second layers 13a and 13b provides vibration damping.

According to an example, the second electrode 13 may comprise two conductive foils arranged to extend parallel to each other. The two conductive foils form a respective one of two second layers 13a and 13b of conductive material. The conductive foil is advantageously made as thin as possible so that its total thickness is substantially the same as the thickness of a conventional foil electrode. Alternatively, the second electrode 13 may comprise a double metallised film. In this case, each metallized surface of the double metallized film forms a respective one of the two second layers 13a and 13 b. The thickness dimension of the film is compressible and allows the two metallized surfaces to move toward or away from each other when the coiled capacitor element is energized.

The coiled capacitor element 9 includes a dielectric layer 15. The dielectric layer 15 may comprise, for example, a polymeric material or any other suitable electrically insulating material, such as a cellulose-based material. The dielectric layer 15 is arranged between the first electrode 11 and the second electrode 13. Thus, the first electrode 11, the dielectric layer 15 and the second electrode 13 are arranged parallel to each other in a sandwich configuration. The first electrode 11, the dielectric layer 15, and the second electrode 13 are wound together to form the wound power capacitor element 9. In this way, a plurality of instances or layers of the first electrode 11, the second electrode 13 and the dielectric layer 15 are provided. As shown in fig. 2, the coiled capacitor element 9 may be flattened to occupy less space in the housing 3. As can be seen, the flattened capacitor element 9 has an oval or rectangular cross section, i.e. a cross section perpendicular to the longitudinal direction of the capacitor element. This has been achieved by: the method includes winding a capacitor element around a spindle to form a cylinder, removing the wound capacitor from the spindle, and flattening or compressing the capacitor element. A majority, e.g. at most 90%, of the active surfaces (i.e. those surfaces defined by the first electrode 11 and the second electrode 13) are in the same plane or parallel to this plane.

The power capacitor 1 in operation will now be described with reference to fig. 4a to 4 c. In fig. 4a, the voltage applied to the power capacitor 1 is at zero crossing and thus the potential at the first electrode 11 and the second electrode 13 is zero. In this case, there is no attractive force between the first electrode 11 and the second electrode 13.

fig. 4b shows a situation where the first electrode 11 has a positive potential. This is illustrated by the arrows on the sinusoidal duty cycle of the alternating voltage. Due to the coulomb attraction force F, for example, in the uppermost layer of the dielectric layer 15, the layer 11a of the first electrode 11 is attracted to the layer 13b arranged on the opposite side of the dielectric layer 15. However, since the layer 13b is at the same potential as the adjacently arranged layer 13a at the same time, they will repel each other. This repulsive movement between the two second layers 13a and 13b results in a compensation of the attractive movement between the layers 11a and 13 b. This compensation results in a cancellation or at least a reduction of the motion, velocity and acceleration at the outermost turn.

in the situation shown in fig. 4c, the voltage applied to the coiled capacitor element 9 again crosses zero. Thus, the first electrode 11 and the second electrode 13 are at the same potential. In the absence of an attractive force between the first electrode 11 and the second electrode 13, the dielectric material 15 will relax, causing the first electrode 11 and the second electrode 13 to move away from each other. The overall cross-sectional dimension of the coiled capacitor element 9 will remain substantially unchanged compared to the situation shown in fig. 4 b.

In fig. 4d, the voltage applied to the power capacitor 1 is in the negative phase of the sinusoidal duty cycle. Thus, the sign of the voltage potential across the first electrode 11 and the second electrode 13 has been shifted compared to the situation illustrated in fig. 4b, but the effect will be the same as described with reference to fig. 4 b.

In this way, the vibrations of the first electrode 11 and the second electrode 13 are partly cancelled and there will therefore be an attenuation of the sound emitted by the power capacitor 1.

the inventive concept has been described above with reference to several examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.