Capacitor

Abstract

A capacitor (1) for high frequency applications is described, comprising at least two winding elements (2) and a plurality of connection elements (3) connecting the winding elements (2) in parallel with each other, each winding element (2) being connected to at least a pair of connection elements (3) having opposite polarity, the capacitor (1) having reduced ESL and / or ESR compared to a conventional cylindrical film capacitor (1). Moreover, use of the capacitor (1) in high frequency applications is described.

Description

Technical Field

[0001] The present invention relates to capacitors for high frequency applications. Furthermore, the present invention relates to the use of capacitors in high frequency applications.

Background Art

[0002] Metallized film DC (direct voltage)-link capacitors are important components for many power electronics applications, namely renewable energy, electric vehicles, traction, motor drives, uninterruptible power supplies, energy transmission and the like.

[0003] The requirements for DC-Link capacitors strongly depend on the parameters of the semiconductors implemented in converters and modulation strategies. The development of semiconductors has changed the characteristics of high-power converters, namely higher switching frequencies, higher harmonic frequencies, lighter cooling systems, higher power densities, more compact designs and the like.

[0004] As a result, to operate properly in such applications, DC-Link capacitors must meet the requirements defined in Table 1 within their operating bandwidth.

[0005]

Table 1

[0006] However, actual film capacitors have parasitic components that must be reduced to meet the above requirements.

[0007] So far, this problem has been solved by flat-winding-based film capacitors (WO2019 / 101802A1), height-reduced single-winding circular film capacitors (TDK Data Sheet “Film capacitors-Power Electronic Capacitors: MKP-DC LSI” October 2013), and four-terminal single-winding circular film capacitors (Electronic Concepts Data Sheet “UNLYTIC(registered trademark) MP3 SERIES”, October 2013). [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of this disclosure is to provide a capacitor with improved characteristics. This object is achieved by a capacitor according to independent terms. [Means for solving the problem]

[0009] According to a first aspect of this disclosure, a capacitor is provided. The capacitor may have a circular or cylindrical shape. Preferably, the capacitor is a cylindrical film capacitor. The capacitor is suitable for integration in power electronics applications such as renewable energy, electric vehicles, towing, motor drives, uninterruptible power supplies, and energy transmission devices.

[0010] A capacitor contains at least two winding elements, i.e., internally wound windings. Of course, a capacitor can contain more than two winding elements, for example, three, four, five, or more. The winding elements are arranged sequentially along the main longitudinal axis of the capacitor.

[0011] A capacitor further includes multiple connection elements, such as connection stripes. These connection elements are configured and arranged to connect winding elements in parallel to one another. Each winding element is connected to at least one pair of connection elements with opposite polarity, e.g., two, three, or more. In other words, each winding element is connected to a connection element with polarity A and a further connection element with polarity B. However, this can be different from pairs of connection elements. For example, each winding element may be connected to two connection stripes with polarity A and one connection stripe with polarity B.

[0012] The capacitor is set and configured to have reduced ESL and / or ESR compared to conventional capacitors. In other words, the components of the capacitor are arranged and interconnected so that the capacitor has very low ESL and / or ESR. This makes the capacitor particularly suitable for integration in high-frequency applications.

[0013] According to one embodiment, the capacitor includes a housing, particularly a metal housing. The housing may include, for example, aluminum. The housing has a cylindrical shape. The winding elements are arranged within the housing. The connecting elements are also arranged (at least primarily) within the housing. The implementation of the metal housing is optional. In alternative embodiments, the capacitor may not include a metal housing.

[0014] At least one connecting element from at least one winding element, for example, one, two, or three connecting elements, is positioned as close as possible to the housing. In particular, the connecting element is positioned as close as possible to the inner surface of the housing. For example, the distance between the connecting element and the inner surface of the housing is between 0.5 mm and 2 mm. Furthermore, the at least one connecting element is positioned parallel to the housing, and in particular parallel to the inner surface of the housing.

[0015] The connecting element close to the metal housing is electromagnetically coupled to it, generating eddy currents on the case that are in the opposite direction to the current flowing through the connecting element. Therefore, the electromagnetic flux generated by the current flowing through the connecting element is partially canceled out, reducing the parasitic self-inductance of the connecting element. Consequently, the capacitor ESL is reduced.

[0016] According to one embodiment, the capacitor includes at least two terminals. The terminals may be external terminals. In other words, the terminals protrude from the outer surface of the housing. The terminals have opposite polarities; that is, one terminal has polarity A and the other terminal has polarity B. The terminals are configured and arranged to electrically connect the capacitor. The terminals are connected to a connecting element. A winding element is connected in parallel to the terminals by the connecting element.

[0017] The winding elements have different heights, i.e., extensions along the main longitudinal axis. In particular, the winding elements located closest to the terminals (i.e., the top winding elements) include heights lower than those of the further winding elements. For example, the height of the top winding elements is between 15% and 85% of the height of the further winding elements.

[0018] The parasitic self-inductance of the top winding element is reduced due to its lower height and the reduced length of its connecting element (electrical connection between the top winding and the terminal). Therefore, since the winding elements are connected in parallel and the inductance is dominated by the one with the lowest self-inductance, the capacitor ESL is greatly reduced.

[0019] According to one embodiment, at least one pair of connecting elements having opposite polarities and belonging to different winding elements is arranged within the core of at least one winding element. In other words, two pairs of connecting elements, four pairs of connecting elements, six pairs of connecting elements, or more, each having opposite polarities (i.e., one connecting element of the pair has polarity A and the other has polarity B), are arranged within the inner hollow region of at least one winding element.

[0020] The pair of connecting elements electrically connect different winding elements. That is, one of the connecting elements may be connected to, for example, the top winding element. The other of the connecting elements may be connected to a further winding element, for example, a winding element following the top winding element.

[0021] Alternatively or additionally, at least one pair of connecting elements having opposite polarity and belonging to the same winding element is placed within the core of at least one winding element. Thus, the pair of connecting elements electrically connects one winding element. That is, all connecting elements of at least one pair of connecting elements may be connected to, for example, the top winding element. Alternatively, all connecting elements of at least one pair of connecting elements may be connected to a further winding element, for example, a winding element following the top winding element.

[0022] The pair of connecting elements is arranged in parallel orientation. This means that the two connecting elements are arranged parallel to each other. The distance between the pair of connecting elements is shortened so that the pair of connecting elements overlap. For example, the distance between two connecting elements belonging to one pair may be between 0.1 mm and 3 mm.

[0023] In each pair of connecting elements, the electromagnetic flux generated by the current flowing through the connecting elements is partially canceled out, reducing the parasitic self-inductance of the connecting elements. Thus, the capacitor ESL is reduced.

[0024] According to one embodiment, at least one pair of connecting elements having opposite polarities and coming from different winding elements is positioned as close as possible to the housing. In other words, two, four, six, or more pairs of connecting elements, each having opposite polarities (i.e., one connecting element of the pair has polarity A and the other has polarity B), are positioned as close as possible to the inner surface of the housing. For example, the distance between a pair of connecting elements and the housing may be between 0.5 mm and 2 mm.

[0025] Said pair of connection elements electrically connects different winding elements. That is, one of the connection elements may be connected to, for example, a top winding element. The other one of the connection elements may be connected to another winding element, for example, a winding element subsequent to the top winding element.

[0026] Alternatively or additionally, at least one pair of connection elements having opposite polarities and belonging to the same winding element is arranged as close as possible to the housing. Therefore, said pair of connection elements electrically connects one single winding element. That is, all connection elements of the at least one pair of connection elements may be connected to, for example, a top winding element. Alternatively, all connection elements of the at least one pair of connection elements may be connected to a further winding element, for example, a winding element subsequent to the top winding element.

[0027] The pair of connection elements is arranged parallel to the housing, in particular parallel to the inner surface of the housing. Furthermore, the pair of connection elements is arranged at the same distance relative to the inner surface of the housing. This means that the distances between these two connection elements and the housing are equal. For example, the distance between each of the two connection elements and the inner surface of the housing may be between 0.5 mm and 2 mm.

[0028] Furthermore, the two connection elements have the smallest possible distance between each other. The distance between two connection elements belonging to one pair may be between 0.1 mm and 3 mm.

[0029] Each pair of connection elements is electromagnetically coupled by the metal housing to generate eddy currents on the housing that have opposite directions relative to the current flowing through the connection elements. Thus, the electromagnetic flux generated by the current flowing through the connection elements is partially canceled, reducing the parasitic self-inductance of the connection elements. As a result, the ESL of the capacitor is reduced.

[0030] According to one embodiment, the capacitor comprises two pairs of terminals. The terminals are configured to electrically connect the capacitor. The terminals are connected to the connection elements.

[0031] The two pairs of terminals include a polarity circular layout ABAB. This means the terminals are arranged in a circular pattern on the outer surface of the capacitor housing. Terminals with opposite polarities are arranged sequentially; that is, a terminal with polarity A is followed by a terminal with polarity B, and so on. Terminals with the same polarity are connected internally.

[0032] The terminal cross-section is thus increased, shortening the electrical distance from the input to the connecting and winding elements, and reducing the parasitic self-inductance from the input to the connecting and winding elements. As a result, the capacitor ESL and ESR are reduced.

[0033] According to one embodiment, the capacitor includes two pairs of terminals. The terminals are configured to electrically connect the capacitor. The terminals are connected to a connecting element.

[0034] The two pairs of terminals include a polarity circular layout AABB. This means the terminals are arranged in a circular pattern on the outer surface of the capacitor housing. Terminals with the same polarity are arranged sequentially; that is, a terminal with polarity A is placed next to another terminal with polarity A, and a terminal with polarity B is placed next to another terminal with polarity B. Terminals with the same polarity are connected internally.

[0035] Consequently, the terminal cross-section is increased, the electrical distance from the input to the connecting and winding elements is shortened, and the parasitic self-inductance from the input to the connecting and winding elements is reduced. As a result, the capacitor ESL and ESR are reduced.

[0036] According to one embodiment, at least one pair of connecting elements having opposite polarities and coming from different winding elements is arranged on the side of at least one winding element. In other words, two pairs of connecting elements, four pairs of connecting elements, six pairs of connecting elements, or more pairs of connecting elements, each having opposite polarities (i.e., one connecting element in the pair has polarity A and the other has polarity B), are arranged along the outer surface of at least one winding element.

[0037] The at least one pair of connecting elements electrically connects different winding elements. That is, one of the connecting elements may be connected to, for example, the top winding element. The other of the connecting elements may be connected to a further winding element, for example, a winding element following the top winding element.

[0038] Alternatively or additionally, at least one pair of connecting elements having opposite polarity and consisting of the same winding element is positioned on the side of at least one winding element. The at least one pair of connecting elements electrically connects one winding element. That is, all connecting elements of the at least one pair of connecting elements may be connected to, for example, the top winding element. Alternatively, all connecting elements of the at least one pair of connecting elements may be connected to a further winding element, for example, a winding element following the top winding element.

[0039] The pair of connecting elements are positioned parallel to each other, that is, parallel to one another. The distance between the two connecting elements is as small as possible so that they overlap. For example, the distance between the two connecting elements may be between 0.1 mm and 3 mm.

[0040] The distance between the housing, particularly the inner surface of the housing, and the two connecting elements may be as small as possible. For example, the distance between the two connecting elements and the housing may be between 0.5 mm and 2 mm. In this case, both connecting elements may be positioned parallel to the housing, i.e., parallel to the main vertical axis of the capacitor / housing.

[0041] In each pair of connecting elements, the electromagnetic flux generated by the current flowing through the connecting elements is partially canceled out, reducing the parasitic self-inductance of the connecting elements. Thus, the capacitor ESL is reduced. The effects described are amplified when the pair of connecting elements are positioned as close as possible to the housing.

[0042] According to one embodiment, at least one trio of connecting elements having opposite polarity ABA and coming from different winding elements is positioned as close to the housing as possible. Alternatively or additionally, at least one trio of connecting elements having opposite polarity ABA and coming from the same winding element is positioned as close to the housing as possible.

[0043] In other words, one, two, or more trios of connecting elements are arranged at the minimum distance from the inner surface of the housing, such that each connecting element of a trio is connected to a different winding element, or each connecting element of a trio is connected to the same winding element. Furthermore, the trios of connecting elements are arranged parallel to the housing. The three connecting elements have alternating polarities. This means that one of the three connecting elements has polarity A, the next connecting element has the opposite polarity B, and so on, with the remaining connecting element again having the opposite polarity A.

[0044] The three connecting elements are positioned at the same distance from the inner surface of the housing. The distance between each of the three connecting elements and the inner surface of the housing may be between 0.5 mm and 2 mm. Furthermore, the three connecting elements belonging to a trio are positioned at the smallest possible distance from each other. For example, the distance between the three connecting elements is between 0.1 mm and 3 mm.

[0045] Each trio of the connecting element is electromagnetically coupled by the metal housing, generating eddy currents on the housing that are in the opposite direction to the current flowing through the connecting element. Thus, the electromagnetic flux generated by the current flowing through the connecting element is partially canceled out, reducing the parasitic self-inductance of the connecting element. In this way, the capacitor ESL is reduced.

[0046] According to one embodiment, at least one trio of connecting elements having opposite polarity ABA and coming from different winding elements is arranged within the core of at least one winding element. Alternatively or additionally, at least one trio of connecting elements having opposite polarity ABA and coming from the same winding element is arranged within the core of at least one winding element.

[0047] In other words, one, two, or more trios of connecting elements are arranged within the inner hollow region of at least one winding element, where each connecting element of a trio is connected to a different winding element, or where each connecting element of a trio is connected to the same winding element. Furthermore, the trios of connecting elements are arranged parallel to each other. The three connecting elements have alternating polarities. This means that one of the three connecting elements has polarity A, the next connecting element has the opposite polarity B, and so on, with the next connecting element again having the opposite polarity A.

[0048] The distance between the three connecting elements belonging to a trio is shortened as much as possible so that the connecting elements overlap. The distance between the three connecting elements may be between 0.1 mm and 3 mm.

[0049] In each trio of connecting elements, the electromagnetic flux generated by the current flowing through the connecting elements is partially canceled out, reducing the parasitic self-inductance of the connecting elements. Thus, the capacitor ESL is reduced.

[0050] It should be understood that the above-mentioned configurations and improvements to capacitors can be implemented within a capacitor, either individually or in combination.

[0051] In a further embodiment, the use of the aforementioned capacitor in high-frequency applications is described. The above-described configurations of the capacitor can be implemented individually or in combination in the capacitor. The capacitor has very low ESR and / or ESL. Therefore, it is ideal for use in high-frequency applications, such as renewable energy, electric vehicles, traction, motor drives, uninterruptible power supplies, energy transmission devices, etc.

[0052] Further configurations, improvements, and conveniences will become apparent from the following description of exemplary embodiments related to the drawings.

[0053] In the figures, elements of the same structure and / or function may be referred to by the same reference number. It should be understood that the embodiments shown in the figures are illustrative and not necessarily drawn to scale. [Brief explanation of the drawing]

[0054] [Figure 1] A simplified electrical model of a film capacitor using the latest technology is shown diagrammatically. [Figure 2] A schematic diagram of a capacitor using the latest technology is shown. [Figure 3] A perspective view of a capacitor according to one embodiment is shown schematically. [Figure 4] A perspective view of a capacitor according to a further embodiment is graphically shown. [Figure 5A] Figure 4 schematically shows the perspective view and top view of the capacitor. [Figure 5B] Figure 4 schematically shows the perspective view and top view of the capacitor. [Figure 5C] Figure 4 schematically shows the perspective view and top view of the capacitor. [Figure 5D] Figure 4 schematically shows the perspective view and top view of the capacitor. [Figure 6] A perspective view of a capacitor according to one embodiment is shown schematically. [Figure 7] A perspective view of a capacitor according to one embodiment is shown schematically. [Figure 8] A perspective view of a capacitor according to one embodiment is shown schematically. [Figure 9A] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 9B] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 9C] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 9D] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 10] A perspective view of a capacitor according to one embodiment is shown schematically. [Figure 11A] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 11B] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 11C] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 11D] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 12A] A perspective view of a capacitor according to a further embodiment is graphically shown. [Figure 12B] A perspective view of a capacitor according to a further embodiment is graphically shown. [Figure 13A] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 13B] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 13C] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 13D] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 14A] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 14B] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 14C] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 14D] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 14E] Figure 12B schematically shows the perspective view and top view of the capacitor. [Figure 15A] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 15B] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 15C] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 15D] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 16A] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 16B] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 16C] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 16D] A perspective view and a top view of a capacitor according to a further embodiment are graphically shown. [Figure 17] A perspective view of a capacitor according to one embodiment is shown schematically. [Figure 18A] Figure 17 schematically shows the perspective view and top view of the capacitor. [Figure 18B] Figure 17 schematically shows the perspective view and top view of the capacitor. [Figure 18C] Figure 17 schematically shows the perspective view and top view of the capacitor. [Figure 18D] Figure 17 schematically shows the perspective view and top view of the capacitor. [Figure 19] A perspective view of a capacitor according to one embodiment is shown schematically. [Figure 20A] Figure 19 schematically shows the perspective view and top view of the capacitor. [Figure 20B] Figure 19 schematically shows the perspective view and top view of the capacitor. [Figure 20C] Figure 19 schematically shows the perspective view and top view of the capacitor. [Figure 20D] Figure 19 schematically shows the perspective view and top view of the capacitor. [Figure 21] An alternative design for the embodiment shown in Figure 16A is shown. [Figure 22] An alternative design for the embodiment shown in Figure 16B is provided. [Figure 23] An alternative design for the embodiment shown in Figure 16C is provided. [Figure 24] An alternative design for the embodiment shown in Figure 16D is shown. [Modes for carrying out the invention]

[0055] Figures 1 and 2 relate to capacitors using the latest technology. Figure 2 shows a conventional cylindrical film capacitor 100. The capacitor 100 comprises two internal winding elements 101 connected in parallel. The winding elements 101 are connected to a pair of external terminals 102 by connection stripes 103. All winding elements 101 have the same height.

[0056] Figure 1 shows the equivalent electrical model of a film capacitor using the latest technology, for example, capacitor 100. As can be seen from Figure 1, capacitor 100 has parasitic components. In particular, the ESL of capacitor 100 is due to the parasitic self-inductance of terminal 102, and the parasitic self-inductance of winding element 101 includes its intrinsic parasitic self-inductance and the self-inductance resulting from the connection between winding element 101 and terminal 102 by the connecting stripe 103.

[0057] For proper operation in high-frequency applications, the parasitic inductance and / or resistance of a capacitor must be reduced.

[0058] Figure 3 schematically shows a perspective view of the capacitor 1 according to the first embodiment.

[0059] Capacitor 1 is a circular or cylindrical film capacitor. Capacitor 1 is configured for use in high-frequency applications. In this embodiment, capacitor 1 includes two internal winding elements 2. Of course, capacitor 1 can include more than two winding elements 2, for example, three, four, five or more winding elements 2.

[0060] The winding elements 2 are connected in parallel. The winding elements 2 are connected to a pair of external terminals 6, 7 by connection elements 3, for example, connection stripes. Specifically, each winding element 2 is connected to a pair of connection elements 3 having opposite polarities. In alternative embodiments, it can be a different connection. For example, each winding element 2 may be connected to two connection stripes 3 with pole A and one connection stripe 3 with pole B. In other words, each winding element 2 is not necessarily connected to exactly one pair of connection elements 3.

[0061] The capacitor 1 includes a cylindrical housing 4. The housing 4 is made of metal. Preferably, the housing 4 is made of aluminum. The winding element 2 and the connecting element 3 are arranged inside the housing 4.

[0062] In this embodiment, one of the connecting elements 3 is positioned as close as possible to the inner surface of the housing 4. In other words, the distance of the connecting element 3 to the inner housing wall is shorter compared to conventional capacitors. For example, the distance between the connecting element 3 and the inner surface of the housing is 0.5 mm to 2 mm.

[0063] Furthermore, the connecting element 3 is positioned parallel to the housing 4, and more particularly parallel to the inner surface of the housing 4. The connecting element 3 is positioned parallel to the main vertical axis x of the housing 4 / capacitor 1. Due to the specific positioning of the connecting element 3, an electromagnetic coupling 5 is formed between the housing 4 and the connecting element 3.

[0064] In the embodiment shown in Figure 3, the connecting element 3 (upper winding element) belonging to the winding element 2 located closest to terminals 6 and 7 is positioned as close as possible to the housing 4. Of course, other connecting elements 3, for example, the connecting element 3 belonging to the winding element 2 furthest from terminals 6 and 7, can be positioned in the manner described above. Of course, more than one connecting element 3 can be positioned as close as possible to the housing 4. For example, two, three, or more connecting elements 3 can be positioned in this manner.

[0065] The connecting element 3, which is close to the metal housing 4, is electromagnetically coupled to it, generating eddy currents on the housing 4 that are in the opposite direction to the current flowing through the connecting element 3. As a result, the electromagnetic flux generated by flowing through the connecting element 3 is partially canceled out, reducing the parasitic self-inductance of the connecting element 3, and consequently reducing the capacitor ESL. Therefore, in this embodiment, the metal housing 4 is used to strongly reduce the ESL of the capacitor 1.

[0066] Figures 4 and 5A to 5D show a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connecting element 3, terminals 6 and 7, and a housing 4, as described in relation to the capacitor 1 in Figure 3. Terminals 6 and 7 protrude from the upper surface 4A of the housing 4 (see Figures 5B and 5D in particular). Furthermore, in this embodiment as well, at least one of the connecting elements 3 can be positioned as close as possible to the housing 4, as described above, in order to reduce the ESL of the capacitor 1 (however, this is not required).

[0067] In addition, to reduce ESL, capacitor 1 includes winding elements 2 with different heights. In particular, the winding elements 2 closest to terminals 6 and 7 (the so-called "upper winding elements") have a lower height h compared to further winding elements 2 with height H (see Figures 4 and 5C in particular). For example, height h is 15% to 85% of the height H of the further winding elements 2. In this context, the term "height" refers to the extension of the winding elements 2 along the main longitudinal axis X of capacitor 1.

[0068] As a result of the reduced height h, the parasitic self-inductance of the upper winding element 2 is reduced. Furthermore, the length of its connecting element 3 (the electrical connection between the upper winding element 2 and terminals 6 and 7) is reduced. Thus, the winding elements 2 are connected in parallel, and the inductance with the lowest self-inductance is dominant, so the capacitor ESL is greatly reduced.

[0069] Figure 6 shows a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connecting element 3, terminals 6 and 7, and a housing 4, as described in relation to the capacitor 1 in Figure 3. The winding element 2 has a core 8, i.e., an inner hollow region extending through the winding element 2 along the main longitudinal axis X.

[0070] Furthermore, in this embodiment as well, at least one of the connecting elements 3 can be positioned as close as possible to the housing 4, as described above, in order to reduce the ESL of the capacitor 1 (however, it is not necessary to do so).

[0071] Furthermore, at least one pair of connecting elements 3 belonging to different winding elements 2 and having opposite polarities is positioned within the core 8 of at least one winding element 2. The pair of connecting elements 3 are positioned parallel to each other. The distance between these two connecting elements 3 is small enough that they overlap within the core region (see overlap region 9). For example, the distance between these two connecting elements 3 is between 0.1 mm and 3 mm.

[0072] Of course, more pairs than one of the connection elements 3, for example two or three pairs, can be arranged in this way, and the maximum number depends on the number of winding elements.

[0073] In each pair of connecting elements 3 arranged in this manner, the electromagnetic flux generated by the current flowing through the connecting elements 3 is partially canceled out, reducing the parasitic self-inductance of the connecting elements 3. As a result, the capacitor ESL is reduced.

[0074] In alternative embodiments not shown in Figure 6, at least one pair of connecting elements 3 belonging to one winding element 2 and having opposite polarity may be located within the core 8 of at least one winding element 2.

[0075] Figure 7 shows a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connecting element 3, terminals 6 and 7, and a housing 4, as described in relation to the capacitor 1 in Figure 3. In this embodiment, as described in relation to Figure 3, the housing 4 is again used to reduce the capacitor ESL.

[0076] In the embodiment shown in Figure 7, at least one pair of connecting elements 3 belonging to different winding elements 2 and having opposite polarities is positioned as close as possible to the housing 4, particularly to the inner surface of the housing 4. Both connecting elements 3 are positioned at the same distance from the housing 4. The distance between each of the two connecting elements 3 and the inner surface of the housing 4 may be between 0.5 mm and 2 mm.

[0077] The connecting element 3 extends parallel to the housing 4, that is, parallel to the main longitudinal axis X. Furthermore, the two connecting elements 3 are positioned as close to each other as possible. For example, the distance between the two connecting elements 3 may be between 0.1 mm and 3 mm. As a result, the two connecting elements 3 overlap.

[0078] Of course, more than one pair of connection element 3, for example, two pairs or three pairs, can be arranged in this way, and the maximum number depends on the number of winding elements.

[0079] Each pair of connection elements 3 is electromagnetically coupled to the metal housing (see electromagnetic coupling 10). This generates eddy currents on the housing 4 that are in the opposite direction to the current flowing through the connection elements 3. In this way, the electromagnetic flux generated by the current flowing through the connection elements 3 is partially canceled out, reducing the parasitic self-inductance of the connection elements 3. As a result, the capacitor ESL is reduced.

[0080] In alternative embodiments not shown in Figure 7, at least one pair of connecting elements 3 belonging to the same winding element 2 and having opposite polarity is positioned as close as possible to the housing 4, particularly to the inner surface of the housing 4.

[0081] Figure 8 shows a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connecting element 3, and a housing 4, as described in relation to the capacitor 1 in Figure 3.

[0082] Again, at least one of the connecting elements 3 can be placed as close as possible to the housing 4 (electromagnetic coupling between housing 4 and connecting element 3) as described above in order to reduce the ESL of capacitor 1 (however, it is not necessary to do so).

[0083] In addition, to further reduce the capacitor ESL / ESR, one pair of connecting elements 3 belonging to different winding elements 2 or one winding element 2 and having opposite polarity can be placed on the core 8 of at least one winding element 2 such that they overlap as already described in relation to Figure 6.

[0084] Furthermore, the capacitor includes two pairs of external terminals 6 and 7. In other words, capacitor 1 includes two first terminals 6 and two second terminals 7. The first and second terminals 6 and 7 have opposite polarities. The first terminal 6 has polarity A, the second terminal 7 has polarity B, and vice versa.

[0085] Terminals 6 and 7 are arranged in a circular pattern on the upper surface 4a of the housing 4. Terminals 6 and 7 are arranged such that one terminal 6 or 7 is always followed by another terminal 7 or 6 with the opposite polarity. In particular, two pairs of terminals 6 and 7 are arranged in a polarity circular layout ABAB. Terminals 6 and 7 with the same polarity are connected internally.

[0086] In this way, the cross-section of terminals 6 and 7 is increased, and the electrical distance from the input (the tops of terminals 6 and 7 to which they are connected externally) to the connecting element 3 and winding element 2 is reduced. Consequently, the parasitic self-inductance from the input to the connecting element 3 and winding element 2 is reduced. As a result, the capacitor ESL and ESR are reduced.

[0087] Figures 9A to 9D show capacitor 1 according to further embodiments. Here, the embodiments shown in Figures 3, 4 and 8 are combined to significantly reduce the ESL and ESR of capacitor 1. This means the following: i) At least one of the connecting elements 3 is positioned as close as possible to the inner surface of the housing 4 so that the connecting element 3 and the housing 4 are electromagnetically coupled (see Figure 9A in particular). ii) The height h of the top winding element 2 is made smaller than the height H of the further winding elements 2 (see Figure 9C in particular). iii) Two pairs of terminals 6 and 7 are provided arranged in a polarity circular layout ABAB, and terminals 6 and 7 with the same polarity are internally connected (see Figure 9D in particular, which shows a top view of capacitor 1 with terminals 6 and 7 arranged in a circular pattern on the top surface 4a of housing 4).

[0088] In combination, these configurations i) to iii) ensure a significant reduction in the ESL of capacitor 1.

[0089] Figure 9D illustrates the connection of terminals 6 and 7 to the connecting element 3 for connecting winding elements 2 in parallel. Terminals with the same polarity are connected internally.

[0090] Figure 10 shows a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connecting element 3, and a housing 4, as described in relation to the capacitor 1 in Figure 3.

[0091] Again, at least one of the connecting elements 3 can be positioned as close as possible to the housing 4 (electromagnetic coupling between the housing 4 and the connecting element 3) as described above in order to reduce the ESL of the capacitor 1 (however, it is not required to be so). Additionally or alternatively, at least one pair of connecting elements 3 belonging to different winding elements 2 and having opposite polarity can be positioned as close as possible to the housing 4, particularly to the inner surface of the housing 4, so that they are electromagnetically coupled to the housing 4 as described in relation to Figure 7. Additionally or alternatively, at least one pair of connecting elements 3 belonging to winding elements 2 and having opposite polarity can be positioned as close as possible to the housing 4, particularly to the inner surface of the housing 4, so that they are electromagnetically coupled to the housing 4 as described in relation to Figure 7.

[0092] To further reduce the capacitor ESL, a pair of connecting elements 3 belonging to different winding elements 2 and having opposite polarities may also be placed within the core 8 of at least one winding element 2 such that they overlap as already described in relation to Figure 6. Additionally or alternatively, to further reduce the capacitor ESL, a pair of connecting elements 3 belonging to one winding element 2 and having opposite polarities may also be placed within the core 8 of at least one winding element 2 such that they overlap as already described in relation to Figure 6.

[0093] In addition, the capacitor includes two pairs of external terminals 6 and 7, namely two first terminals 6 and two second terminals 7. The first and second terminals 6 and 7 have opposite polarities. The first terminal 6 has polarity A, the second terminal 7 has polarity B, and vice versa.

[0094] Terminals 6 and 7 are arranged in a circular pattern on the upper surface 4a of the housing 4 (see also Figures 11A and 11D). Terminals 6 and 7 are arranged such that one terminal 6 or 7 is followed by another terminal 6 or 7 of the same polarity. In particular, the two pairs of terminals 6 and 7 are arranged in a polarity circular layout AABB. Terminals 6 and 7 with the same polarity are connected internally.

[0095] Due to the specific arrangement of terminals 6 and 7, the cross-sectional area of ​​terminals 6 and 7 increases, and the electrical distance from the input to the connecting element 3 and winding element 2 decreases. Consequently, the parasitic self-inductance from the input to the connecting element 3 and winding element 2 is reduced. As a result, the capacitor ESL and ESR are further reduced.

[0096] Figures 11A to 11D show capacitor 1 according to further embodiments. Here, the embodiments shown in Figures 3, 4, 7, and 10 are combined to significantly reduce the ESL of capacitor 1. This means the following: - At least one pair of connecting elements 3, either from different winding elements 2 or belonging to the same winding element 2 and having opposite polarities, is positioned as close as possible to the housing 4, particularly to the inner surface of the housing 4, so that the pair of connecting elements 3 and the housing 4 are electromagnetically coupled. (See Figure 11A in particular). - In addition, a further (single) connecting element 3 can be positioned as close as possible to the housing 4 in order to electromagnetically couple with the housing 4. - The height h of the top winding element 2 is made smaller compared to the height H of the further winding elements 2 (see Figure 11C in particular). - Two pairs of terminals 6 and 7 are provided, arranged in a polarity circular layout AABB, and terminals 6 and 7 with the same polarity are internally connected (see in particular Figure 11D, which shows a top view of capacitor 1 with terminals 6 and 7 arranged in a circular pattern on the top surface of housing 4).

[0097] In combination, these configurations ensure a significant reduction in the ESL of capacitor 1.

[0098] Figure 11D further illustrates the connection of terminals 6 and 7 with the connecting element 3 for connecting the winding elements 2 in parallel. Terminals 6 and 7, having the same polarity, are connected internally.

[0099] Figure 12A shows a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connection element 3, terminals 6, 7, and a housing 4. In this embodiment, at least one pair of connection elements 3 having opposite polarity and belonging to different winding elements 2 is positioned on the side of at least one winding element 2. In other words, the pair of connection elements 3 extends along the outside of the winding element 2. The pair of connection elements 3 extends parallel to the main longitudinal axis X.

[0100] This pair of connecting elements 3 are arranged in parallel orientations. Furthermore, the distance between the two connecting elements 3 is reduced as much as possible so that they overlap (see overlap region 11). For example, the distance between the two connecting elements 3 may be between 0.1 mm and 3 mm.

[0101] Of course, more than one pair of connection element 3, for example, two pairs or three pairs, can be arranged in this way, and the maximum number depends on the number of winding elements.

[0102] In each pair of connecting elements 3, the electromagnetic flux generated by the current flowing through the connecting elements 3 is partially canceled out, reducing the parasitic self-inductance of the connecting elements 3. As a result, the capacitor ESL is reduced.

[0103] In alternative embodiments not shown in Figure 12A, at least one pair of connecting elements 3 having opposite polarity and belonging to the same winding element 2 is positioned on the side of at least one winding element 2.

[0104] Figures 12B, 13A–13D, and 14A–14E show capacitor 1 according to further embodiments, where the embodiments of Figure 3 and Figure 12A are combined. Specifically, at least one pair of connecting elements 3, positioned on the side of at least one winding element 2 (see overlapping region 11), is positioned as close to the housing 4 as possible so that the pair of connecting elements 3 and the housing 4 are electromagnetically coupled. Furthermore, one pair of connecting elements 3 is positioned parallel to the inner surface of the housing 4, i.e., parallel to the main longitudinal axis X.

[0105] In this way, the effect described in relation to Figure 12A is amplified, and the capacitor ESL is strongly reduced.

[0106] Figures 13D and 14E additionally show connection points 13 on the upper surface 4a of the housing. In this embodiment, connection points are soldering points.

[0107] The connection point 13 ensures good contact between the connecting element 3 and each winding element 2, which is formed by the connecting stripe. The figure shows a connection point 13 between a connecting element 3 and the uppermost winding element 2. However, all connections between one of the connecting elements 3 and one of the winding elements 2 may include a connection point 13, which may be formed by soldering; that is, all connections may include a soldering point that forms their respective connection point 13. Alternatively, some or all of the connections between one of the connecting elements 3 and one of the winding elements 2 may be formed by welding. In this case, the connection point 13 is a weld point.

[0108] Figures 15A to 15D and 16A to 16D show capacitor 1 according to further embodiments. Here, embodiments according to Figures 3, 8, 12A and / or 12B are combined to further reduce the ESL / ESR of the capacitor. Specifically, this is as follows: - At least one pair of connecting elements 3 having opposite polarities and belonging to different winding elements 2, or belonging to the same winding element 2, is positioned on the side of at least one winding element 2. As discussed in relation to Figure 12a, their distance is minimized so that they overlap (overlap region 11). - The pair of connecting elements 3 can be positioned parallel to the housing 4 and as close to the housing 4 as possible so that the pair of connecting elements 3 and the housing 4 are electromagnetically coupled (see Figure 12B). - Two pairs of terminals 6 and 7 are provided, arranged in a polarity circular layout ABAB, and terminals 6 and 7 with the same polarity are internally connected (see in particular Figure 15D, which shows a top view of capacitor 1 with terminals 6 and 7 arranged in a circular pattern on the upper surface 4a of housing 4).

[0109] By combining different embodiments, the capacitor ESL and ESR are significantly reduced.

[0110] Figure 15D further shows connection points 13 on the upper surface 4a of the housing 4 for securing a copper strip to the upper surface 4a. This helps to secure the connection element 3 to terminals 6, 7. In this embodiment, two connection points 13 formed by soldering are shown. However, embodiments with one connection point 13 are also possible. For example, the enclosed connection point 13 may be omitted. Figure 16D shows two soldering points 13. However, in some embodiments, three or four connection points 13, highlighted by circles in Figure 16D, may also be possible.

[0111] Figures 17 and 18a to 18d show a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connecting element 3, terminals 6 and 7, and a housing 4.

[0112] In this embodiment, at least one trio of connection elements 3, each having opposite polarity (ABA) and belonging to a different winding element 2, is positioned as close as possible to the housing 4. The three connection elements 3 are positioned at the same distance from the housing 4. For example, the distance between each of the three connection elements 3 and the inner surface of the housing 4 is between 0.5 mm and 2 mm. Thus, the three connection elements 3 and the housing 4 are electromagnetically coupled (see electromagnetic coupling 12). In other words, in this embodiment as well, the metal housing 4 is used to reduce the capacitor ESL.

[0113] The three connecting elements 3 are positioned parallel to the inner surface of the housing 4. Furthermore, the three connecting elements 3 are positioned very close to each other. For example, the distance between the three connecting elements 3 may be between 0.1 mm and 3 mm. The three connecting elements 3 overlap each other.

[0114] Each trio of connection element 3 is electromagnetically coupled by the metal housing 4, generating eddy currents on the housing 4 that are in the opposite direction to the direction of the current flowing through connection element 3. Thus, the electromagnetic flux generated by the current flowing through connection element 3 is partially canceled out, reducing the parasitic self-inductance of connection element 3. Therefore, the capacitor ESL is reduced.

[0115] Figure 18D further shows the aforementioned connection point 13 on the upper surface 4a of the housing 4. In this embodiment, two connection points 13 are shown. However, embodiments with one connection point 13 are also possible. For example, the enclosed connection point 13 may be omitted.

[0116] In an alternative embodiment, at least one trio of connecting elements 3 having opposite polarity (ABA) and belonging to the same winding element 2 is positioned as close to the housing 4 as possible.

[0117] Figures 19 and 20A to 20D show a capacitor 1 according to a further embodiment. The capacitor 1 includes a winding element 2, a connecting element 3, and a housing 4.

[0118] Again, at least one of the connecting elements 3 can be positioned as close as possible to the housing 4 (electromagnetic coupling between housing 4 and connecting element 3) as described above in order to reduce the ESL of capacitor 1 (however, this is not required) (see Figure 3).

[0119] In addition, two pairs of terminals 6 and 7 are provided, arranged in a polarity circular layout ABAB, and terminals 6 and 7 with the same polarity are internally connected (see also Figure 8). In this way, the capacitor ESL is further reduced.

[0120] Furthermore, at least one trio of connecting elements 3 having opposite polarities (ABA) and belonging to different winding elements 2 is arranged within the core 8 of at least one winding element 2. In other words, the trio is arranged within the hollow internal region of at least one winding element 2. The connecting elements 3 are arranged parallel to each other.

[0121] The three connecting elements 3 are placed as close to each other as possible. For example, the distance between the three connecting elements 3 may be between 0.1 mm and 3 mm. The three connecting elements 3 overlap each other (see overlapping region 14).

[0122] In each trio of connection element 3, the electromagnetic flux generated by the current flowing through connection element 3 is partially canceled out. Therefore, the parasitic self-inductance of connection element 3 is reduced, and as a result, the capacitor ESL is reduced.

[0123] Overall, the combination of embodiments further reduces the capacitor ESL.

[0124] In an alternative embodiment, at least one trio of connecting elements 3 having opposite polarity (ABA) and belonging to the same winding element 2 is placed within the core 8 of at least one winding element 2.

[0125] Figures 21, 22, 23, and 24 show alternative designs of the embodiments shown in Figures 16A, 16B, 16C, and 16D. According to one design change, in the alternative designs shown in Figures 21, 22, 23, and 24, four connection points 13 are formed on the upper surface of the housing. [Explanation of Symbols]

[0126] 1 Capacitor 2. Winding element 3 connection elements 4 Housing 4a Top side 4b Bottom side 5 Electromagnetic coupling 6 terminals 7 terminals 8 cores 9. Overlap area 10 Electromagnetic coupling 11 Overlap area 12 Electromagnetic coupling 13 connection points 14. Overlap area H Height h height 100 Capacitors 101 Winding element 102 terminals 103 Connection Stripe

Claims

1. Capacitors for power electronics applications, - At least two winding elements, - Includes a plurality of connecting elements that connect the winding elements in parallel with each other, The aforementioned connecting element is formed by a connecting stripe, Each winding element is connected to at least one pair of connecting elements with opposite polarity. At least one pair of connecting elements from different winding elements with opposite polarities are arranged on the sides of at least one winding element with parallel orientations, and the distance between the two connecting elements is as small as possible so that the connecting elements overlap. And / or, At least one pair of connecting elements from one winding element having opposite polarity is positioned on the sides of at least one winding element having parallel orientations, and the distance between the two connecting elements is as small as possible so that the connecting elements overlap. Capacitor.

2. The capacitor according to claim 1, further comprising a metal housing, wherein the winding element is disposed within the housing, and at least one of the connecting elements is positioned as close as possible to the inner surface of the housing, and the at least one connecting element is positioned parallel to the inner surface of the housing.

3. The capacitor according to claim 2, wherein the distance between the inner surface of the housing and the at least one connecting element is between 0.5 mm and 2 mm.

4. The capacitor according to claim 2 or 3, wherein the housing and at least one of the connecting elements are electromagnetically coupled to each other.

5. The capacitor according to any one of claims 1 to 4, further comprising at least two terminals for electrically connecting the capacitor, wherein the winding element positioned closest to the terminals has a height less than the height of the remaining winding elements.

6. At least one pair of connecting elements from different winding elements with opposite polarities are arranged within the core of at least one winding element having parallel orientations, and the distance between the pair of connecting elements is reduced such that the pair of connecting elements overlap. And / or, At least one pair of connecting elements from one winding element having opposite polarity is located within the core of at least one winding element having parallel orientations, and the distance between the pair of connecting elements is reduced such that the pair of connecting elements overlap. A capacitor according to any one of claims 1 to 5.

7. The capacitor according to claim 6, wherein the distance between the two connecting elements is between 0.1 mm and 3 mm.

8. At least one pair of connecting elements from different winding elements with opposite polarities is positioned as close as possible to the housing and parallel to the housing, And / or, At least one pair of connecting elements from one winding element having opposite polarity is positioned as close as possible to the housing and parallel to the housing. The capacitor according to claim 2.

9. The capacitor according to claim 8, wherein at least one pair of the connecting elements are positioned at the same distance from the inner surface of the housing and have the lowest possible distance between them.

10. A capacitor according to any one of claims 1 to 9, further comprising two pairs of terminals for electrically connecting the capacitor, wherein the two pairs of terminals include a polarity circular layout A-B-A-B, and terminals having the same polarity are internally connected.

11. A capacitor according to any one of claims 1 to 9, further comprising two pairs of terminals for electrically connecting the capacitor, wherein the two pairs of terminals include a polarity circular layout A-A-B-B, and terminals having the same polarity are internally connected.

12. A capacitor according to any one of claims 1 to 11, comprising at least two terminals for electrically connecting the capacitor, wherein the terminals are directly connected to the connecting element.

13. The capacitor according to any one of claims 1 to 12, wherein the distance between the two connecting elements is reduced as much as possible so that the two connecting elements overlap in the overlap region.

14. The capacitor according to any one of claims 1 to 13, wherein the distance between the two connecting elements is between 0.1 mm and 3 mm.

15. The capacitor according to any one of claims 1 to 14, wherein the distance between the inner surface of the housing and the two connecting elements is between 0.5 mm and 2 mm, and both connecting elements are arranged parallel to the housing.

16. At least one trio of the connecting elements from different winding elements having opposite polarities A-B-A is positioned as close as possible to the housing and parallel to the housing, And / or, At least one trio of the connecting elements from one winding element having opposite polarities A-B-A is positioned as close as possible to the housing and parallel to the housing. The capacitor according to claim 2.

17. The capacitor according to claim 16, wherein the three connecting elements are arranged at the same distance from the inner surface of the housing and are at the lowest possible distance from one another.

18. At least one trio of the connecting elements from different winding elements having opposite polarities A-B-A is arranged within the core of at least one winding element having parallel orientations, and the distance between them is reduced as much as possible so that the connecting elements overlap. And / or, At least one trio of the connecting elements from one winding element having opposite polarities A-B-A is arranged within the core of at least one winding element having parallel orientations, and the distance between them is reduced as much as possible so that the connecting elements overlap. A capacitor according to any one of claims 1 to 17.

19. The capacitor according to claim 18, as dependent on claim 17, wherein the distance between the three connecting elements is 0.1 mm to 3 mm.

20. An apparatus using a capacitor according to any one of claims 1 to 19.

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