Capacitor assembly comprising a capacitor element which has a first capacitor and a second capacitor

Abstract

The present invention relates to a capacitor assembly (1) comprising a capacitor element (2) which has a first capacitor (3) and a second capacitor (4). The first capacitor (3) and the second capacitor (4) each have a layered or wound structure, wherein one first electrode each can be contacted via a first contact element on a first side of each capacitor (3, 4), while one second electrode each can be contacted via a second contact element on a second side of each capacitor (3, 4), wherein the first contact element (7) of the first capacitor (3) and the first contact element (7') of the second capacitor (4) are located on a common side of the capacitor assembly (1) corresponding to the first side, while the second contact element (8) of the first capacitor (3) and the second contact element (8') of the second capacitor (4) are located on a common side of the capacitor assembly (1) corresponding to the second side, and wherein the second contact element (8) of the first capacitor (3) is electrically conductively connected to the second contact element (8') of the second capacitor (4).

Description

[0001] Description

[0002] title

[0003] Capacitor arrangement with a capacitor element which has a first capacitor and a second capacitor

[0004] State of the art

[0005] The present invention relates to a capacitor arrangement with a capacitor element which has a first capacitor and a second capacitor.

[0006] Ceramic capacitors with an extremely low inductance value have been available for several years under the brand name LIGA. These capacitors are ideal as buffers for extremely dynamic loads, such as those encountered in the power supply of CPUs and GPUs. The underlying concept involves layering the two electrodes. Unlike with classic MLCCs, however, a one-sided, alternating wiring arrangement is chosen. The electrodes carry the current in opposite directions. This special type of wiring largely compensates for the magnetic field and thus greatly reduces the effective inductance. However, the concept cannot be transferred 1:1 to the field of power electronics, since the operating voltages and currents are significantly higher, particularly at the vehicle or grid level.

[0007] Disclosure of the invention

[0008] The capacitor arrangement according to the invention comprises a capacitor element which comprises a first capacitor and a second capacitor, wherein the first capacitor and the second capacitor each have a layered or wound structure, wherein a first electrode can be contacted via a first contact element on a first side of the respective capacitor, wherein a second electrode can be contacted via a second contact element on a second side of the respective capacitor, wherein the first contact element of the first capacitor and the first contact element of the second capacitor are arranged on a common side of the capacitor arrangement corresponding to the first side, wherein the second contact element of the first capacitor and the second contact element of the second capacitor are arranged on a common side of the capacitor arrangement corresponding to the second side,and wherein the second contact element of the first capacitor is electrically conductively connected to the second contact element of the second capacitor.,

[0009] The capacitor arrangement, in particular, creates an intermediate circuit capacitor with a particularly low-inductance design. The design according to the invention preferably allows the integration of a low-inductance center tap via the second contact elements of the two capacitors. This makes the capacitor arrangement according to the invention particularly suitable for circuit topologies that require a center tap of the intermediate circuit, e.g., for T-type inverters.

[0010] The first capacitor and the second capacitor optionally have a layered structure. In this case, the first and the second capacitor each comprise a plurality of first and second electrode layers. Each of the electrode layers has a plate-like structure. The plurality of first electrode layers and the plurality of second electrode layers are layered alternately. This means that a first electrode layer always rests on a second electrode layer. The electrode layers are insulated to prevent short circuits between the superimposed electrode layers.

[0011] As an alternative to the layered structure, the first capacitor and the second capacitor have a wound structure. In this case, the first and second capacitors typically each comprise a first and a second electrode layer. Each of the electrode layers is a flexible layer. The two electrode layers are placed on top of one another during production and wound together to form multilayer electrode layers. The electrode layers are insulated to prevent short circuits between the superimposed electrode layers.

[0012] The first contact element of the first capacitor and the first contact element of the second capacitor are arranged on a common side of the capacitor arrangement corresponding to the first side. The second contact element of the first capacitor and the second contact element of the second capacitor are arranged on a common side of the capacitor arrangement corresponding to the second side. Thus, the first contact elements and the second contact elements are on different sides of the capacitor arrangement. This prevents voltages from jumping between the contact elements and allows the capacitor assembly to be designed for higher operating voltages. This distinguishes the concept from LIGA capacitors, which have each electrode leading out on the same side.

[0013] The second contact element of the first capacitor is electrically conductively connected to the second contact element of the second capacitor. The first and second capacitors can thus form a common capacitance between the first contact elements or can be used as two separate capacitances located between the first and second contact elements of the first capacitor and the first and second contact elements of the second capacitor.

[0014] The subclaims show preferred developments of the invention.

[0015] Preferably, the first capacitor and the second capacitor each have at least a first electrode layer and a second electrode layer, wherein the first electrode layer protrudes beyond the second electrode layer on the first side, wherein the second electrode layer protrudes beyond the first electrode layer on the second side, wherein the first electrode layer is contacted on the first side via a first contact element which rests on the front side of the first electrode layer, and wherein the second electrode layer is contacted on the second side via a second contact element which rests on the front side of the second electrode layer. The first electrode layer protrudes beyond the second electrode layer on a first side.

[0016] For example, in a layered structure of the capacitors, the first electrode layers are the same size as the second electrode layers and are arranged offset to them. In a region in which there is no second electrode layer between two consecutive first electrode layers, the first electrode layers protrude beyond the second electrode layers. The second electrode layers protrude beyond the first electrode layers on a second side. For example, the second electrode layers are the same size as the first electrode layers and are arranged offset to them. In a region in which there is no first electrode layer between two consecutive second electrode layers, the second electrode layers protrude beyond the first electrode layers. The first side is not the same as the second side.

[0017] In a wound capacitor structure, the first electrode layer, for example, has the same dimensions as the second electrode layer, and the two electrode layers are wound offset from one another. In an area where no layer of the second electrode layer is located between two consecutive layers of the first electrode layer in a winding, the first electrode layer protrudes beyond the second electrode layer. Similarly, the second electrode layer protrudes beyond the first electrode layer on the second side. The first side is not equal to the second side.

[0018] The first electrode layer or the first electrode layers of a capacitor are contacted on the first side via the first contact element, which rests on the front side on the first electrode layer of each of the first electrode layers.

[0019] The first electrode layer has opposing surfaces and a circumferential edge. The second electrode layer also has opposing surfaces and a circumferential edge. This applies to each of the electrode layers, even if the capacitors have a plurality of first and second electrode layers. In the layered structure, at least one of the opposing surfaces of each first electrode layer lies flat on one of the opposing surfaces of a second electrode layer. An end face of the opposing surfaces, which corresponds to one side of the circumferential edges, is one of the remaining sides of the electrode layers that connects the opposing surfaces to one another. The first capacitor preferably has a symmetrical structure to the second capacitor.

[0020] The first electrode layers and the second electrode layers of the layered first capacitor are preferably arranged parallel to the first electrode layers and the second electrode layers of the second capacitor. This means that the opposing plate surfaces of the electrode layers lie in parallel planes. Further preferably, the first electrode layers and the second electrode layers of the layered first capacitor are preferably arranged parallel to the first electrode layers and the second electrode layers of the second capacitor with a maximum deviation of two degrees. This means that the opposing plate surfaces of the electrode layers lie in parallel planes.

[0021] Each of the capacitors preferably has the same number of first electrode layers and second electrode layers.

[0022] Preferably, the second contact element of the first capacitor is formed integrally with the second contact element of the second capacitor. This creates a particularly low resistance in the contact.

[0023] The capacitor element preferably further comprises a first conductor element which is arranged between the first capacitor and the second capacitor, which is connected on the second side to the second contact element of the first capacitor and the second contact element of the second capacitor, and which enables contacting of the second contact elements on the first side. The first conductor element is preferably formed in one piece with the second contact elements. The first capacitor and the second capacitor preferably lie on the first conductor element, or the individual capacitor elements are connected to the conductor via thermally conductive materials. The first conductor element thus enables heat dissipation and reduces heat build-up between the first capacitor and the second capacitor.The first conductor element thus creates a center tap, whereby all contacts of the capacitor element can be contacted from a common side.

[0024] Likewise preferably, the capacitor element further comprises two second conductor elements, which are located on opposite sides of the first capacitor and the second capacitor, are connected on the second side to the second contact elements of the first capacitor and the second contact element of the second capacitor, and on the first side each enable contact to be made with the second contact elements. The two second conductor elements thus encompass the capacitor element together with the second contact elements. The second conductor elements are preferably formed integrally with the second contact elements. The first capacitor and the second capacitor each rest on a second conductor element. Heat dissipation is thus enabled by the second conductor elements. A center tap is thus created by the second conductor elements, wherein all contacts of the capacitor element can be contacted from a common side.

[0025] Preferably, the first contact element of the first capacitor is arranged in a common plane with the first contact element of the second capacitor, and / or the second contact element of the first capacitor is arranged in a common plane with the second contact element of the second capacitor. The common plane is preferably perpendicular to the plane in which the electrode layers of layered capacitors lie or perpendicular to a winding axis in wound capacitors.

[0026] Preferably, the first contact element and the second contact element of the first capacitor are arranged on opposite sides of the first capacitor, and the first contact element and the second contact element of the second capacitor are arranged on opposite sides of the second capacitor.

[0027] The capacitor arrangement preferably comprises a plurality of capacitor elements. Thus, the capacitance of the capacitor arrangement can be adjusted in a modular manner and the inductance can be reduced simultaneously. Preferably, the second contact elements of all capacitor elements are formed as a single piece, so that the capacitor arrangement has a single contact element that encompasses all second contact elements.

[0028] Preferably, the capacitor elements are layered such that the first capacitors and the second capacitors of the capacitor elements are arranged alternately. This achieves a particularly uniform current flow, in which the resulting magnetic fields cancel each other out particularly efficiently.

[0029] Preferably, the capacitor arrangement is designed for an operating voltage of more than 50 volts. Current systems in electromobility and other power electronics require efficient capacitor arrangements with low inductance values, which is made possible by the present invention.

[0030] The capacitor element preferably has a symmetrical structure, which also means that the resulting magnetic fields cancel each other out particularly efficiently.

[0031] In summary, a clever arrangement of the center tap between the split capacitors, provided by the second contact elements, enables a particularly low-inductance design, thus making it suitable for applications in power electronics with high power density and high efficiency. This achieves a more homogeneous current density in the intermediate circuit capacitor and its elements, thus increasing the continuous power.

[0032] The gain in efficiency and power density results in particular from the compact design and the low inductance values.

[0033] Switching speeds can be increased, allowing the potential of modern semiconductors (SiC, GaN) to be better utilized.

[0034] Short description of the drawings

[0035] Embodiments of the invention will be described in detail below with reference to the accompanying drawings. Figure 1 shows a circuit diagram of an exemplary intermediate circuit comprising two capacitors.

[0036] Figure 2 is a circuit diagram of an inventive

[0037] capacitor arrangement,

[0038] Figures 3a to 3d are schematic representations of different capacitor arrangements according to the invention in a sectional view,

[0039] Figure 4 is a schematic representation of an inventive

[0040] Capacitor arrangement with several capacitor elements, and

[0041] Figures 5a to 5c show schematic representations of different capacitor arrangements according to the invention in a plan view.

[0042] Embodiments of the invention

[0043] Figure 1 shows a circuit diagram of an exemplary intermediate circuit comprising two capacitors C1, C2. The intermediate circuit has the two capacitors C1, C2, which can be provided by a capacitor arrangement 1 according to the invention. In this case, the capacitors C1 and C2 comprise a first capacitor 3 and a second capacitor 4 of the capacitor arrangement 1. In the circuit arrangement shown, the first capacitor 3 and the second capacitor 4 are connected in series, with a first contact of the first capacitor being coupled to a positive current bus DC+ and a first contact of the second capacitor 4 being coupled to a negative current bus DC-. The second contacts of the first capacitor 3 and the second capacitor 4 are connected to one another. A center tap 11 is provided between the first capacitor 3 and the second capacitor 4.

[0044] A circuit output 12 of the intermediate circuit is connected via a first transistor

[0045] S1 is coupled to the positive current bus DC+. The circuit output 12 is further coupled to the negative current bus DC- via a second transistor S2. The circuit output 12 is further coupled to the center tap 11 via a third transistor S3 and a fourth transistor S4. By appropriately switching the transistors S1 to S4, either the positive voltage of the positive current bus DC+, a negative voltage of the negative current bus DC-, or a voltage between the positive and negative voltages, which is tapped from the center tap 11, can be provided at the circuit output 12.

[0046] The combination of the first capacitor 3 and the second capacitor 4 is also referred to as an intermediate circuit capacitor. The intermediate circuit capacitor is provided by the capacitor arrangement 1, which achieves a particularly low-inductance design. The design of the capacitor arrangement 1 allows the integration of a low-inductance center tap, illustrated here using the example of a 2-level intermediate circuit. The capacitor arrangement 1 according to the invention is particularly suitable for circuit topologies in which a center tap of the intermediate circuit is required, e.g., in T-type inverters. The center tap 11 is also referred to as a center tap.

[0047] Figure 2 shows a circuit diagram of a capacitor arrangement 1 according to the invention. The capacitor arrangement 1 has exactly one capacitor element 2. Thus, Figure 2 also shows a circuit diagram of an exemplary capacitor element 2.

[0048] The capacitor element 2 has a first connection contact 13, a second connection contact 14 and a third connection contact 15. The first connection contact 13 is created by a first contact element 7 of the first capacitor 3. The second connection contact 14 is created by contacting a second contact element 8 of the first capacitor 3 and a second contact element 8' of the second capacitor 4. The third connection contact 15 is created by a first contact element 7' of the second capacitor 4. In the circuit shown in Figure 1, the capacitor arrangement 1 is arranged such that the first connection contact 13 is coupled to the positive current bus DC+, the third connection contact 15 is coupled to the negative current bus DC- and the center tap 11 is created by the second connection contact 14. Figures 3a to 3d show exemplary capacitor arrangements 1, each comprising a capacitor element 2.It should be noted that the capacitor elements 1, 2 shown in Figures 3a to 3d can be combined in any desired manner to form a capacitor arrangement 1. The capacitor arrangements 1 shown in Figures 3a to 3d are shown in a sectional view. Therefore, the first capacitor 3 and the second capacitor 4 can be understood as either a layered or a wound capacitor.

[0049] Figure 3a shows a capacitor element 2 comprising the first capacitor 3 and the second capacitor 4. The capacitor element 2 has a symmetrical structure, with a plane of symmetry located between the first capacitor 3 and the second capacitor 4.

[0050] In a first embodiment, the first capacitor 3 has a layered structure. A plurality of first electrode layers

[0051] 5 of the first capacitor 3 and a plurality of second electrode layers

[0052] 6 of the first capacitor 3 are layered alternately with one another. The first electrode layers 5 of the first capacitor 3 and the second electrode layers 6 of the first capacitor 3 are layered alternately with one another. The first electrode layers 5 of the first capacitor 3 and the second electrode layers 6 of the first capacitor 3 are essentially plate-shaped elements, with a first electrode layer 5 of the first capacitor 3 lying on a second electrode layer 6 of the first capacitor 3. The first electrode layers 5 of the first capacitor 3 have the same dimensions as the second electrode layers 6 of the first capacitor 3. The first electrode layers 5 of the first capacitor 3 protrude beyond the second electrode layers 6 of the first capacitor 3 on a first side. The first side is located at the bottom in Figure 3a.Since the first electrode layers 5 of the first capacitor 3 have the same dimensions as the second electrode layers 6 of the first capacitor 3, the second electrode layers 6 of the first capacitor 3 protrude beyond the first electrode layers 5 of the first capacitor 3 on a second side, wherein the second side is a side of the electrode layers 5, 6 of the first capacitor 3 opposite the first side. The second side is thus located at the top in Figure 3a. The electrode layers 5, 6 of the first capacitor 3 are either coated or embedded in a potting compound in order to prevent a short circuit between the first electrode layers 5 of the first capacitor 3 and the second electrode layers 6 of the first capacitor 3.Alternatively or additionally, an insulating element is arranged between adjacent electrode layers 5, 6 of the first capacitor 3 in order to insulate them from one another.

[0053] The first electrode layers 5 of the first capacitor 3 are contacted on the first side via a first contact element 7 of the first capacitor 3, which rests on the end face of each of the first electrode layers 5 of the first capacitor 3. The end face of the first electrode layers 5 of the first capacitor 3 is in each case the side of the first electrode layers 5 that is located towards the first side, i.e., at the bottom in Figure 3a. The first contact element 7 of the first capacitor 3 is, for example, welded or soldered to the first electrode layers 5. The first contact element 7 thus contacts all of the first electrode layers 5 of the first capacitor 3. In Figure 3a, the first contact element 7 of the first capacitor 3 is, for example, a positive connection contact of the capacitor element 2.

[0054] The second electrode layers 6 of the first capacitor 3 are contacted on the second side via a second contact element 8, which rests on the end face of each of the second electrode layers 6 of the first capacitor 3. The end face of the second electrode layers 6 of the first capacitor 3 is in each case the side of the second electrode layers 5 that is located towards the second side, i.e., at the top in Figure 3a. The second contact element 8 of the first capacitor 3 is, for example, welded or soldered to the second electrode layers 6 of the first capacitor 3. The second contact element 8 of the first capacitor 3 thus contacts all of the second electrode layers 6 of the first capacitor 3. In Figure 3a, the second contact element 8 of the first capacitor 3 is, for example, the center tap of the capacitor element 2.

[0055] The second capacitor 4 has a structure corresponding to the first capacitor 3, which is optionally designed as a mirror image of the first capacitor 3. The second capacitor 4 also has a layered structure. A plurality of first electrode layers 5' of the second capacitor 4 and a plurality of second electrode layers 6' of the second capacitor 4 are layered alternately with one another. The first electrode layers 5' of the second capacitor 4 and the second electrode layers 6' of the second capacitor 4 are layered alternately with one another. The first electrode layers 5' of the second capacitor 4 and the second electrode layers 6' of the second capacitor 4 are essentially plate-shaped elements, with a first electrode layer 5' of the second capacitor 4 resting on a second electrode layer 6' of the second capacitor 4.The first electrode layers 5' of the second capacitor 4 have the same dimensions as the second electrode layers 6' of the second capacitor 4. The first electrode layers 5' of the second capacitor 4 protrude beyond the second electrode layers 6' of the second capacitor 4 on a first side. The first side is located at the bottom in Figure 3a. Since the first electrode layers 5' of the second capacitor 4 have the same dimensions as the second electrode layers 6' of the second capacitor 4, the second electrode layers 6' of the second capacitor 4 correspondingly protrude beyond the first electrode layers 5' of the second capacitor 4 on a second side, wherein the second side is a side of the electrode layers 5', 6' of the second capacitor 4 opposite the first side. The second side is thus located at the top in Figure 3a.The electrode layers 5', 6' of the second capacitor 4 are either coated or embedded in a potting compound to prevent a short circuit between the first electrode layers 5' of the second capacitor 4 and the second electrode layers 6' of the second capacitor 4. Alternatively or additionally, an insulating element is arranged between adjacent electrode layers 5', 6' of the second capacitor 4 to insulate them from each other.

[0056] The first electrode layers 5' of the second capacitor 4 are contacted on the first side via a first contact element 7' of the second capacitor 4, which rests on the end face of each of the first electrode layers 5' of the second capacitor 4. The end face of the first electrode layers 5' of the second capacitor 4 is the side of the first electrode layers 5' that is located toward the first side, i.e., at the bottom in Figure 3a. The first contact element 7' of the second capacitor 4 is, for example, welded or soldered to the first electrode layers 5'. The first contact element 7' thus contacts all of the first electrode layers 5' of the second capacitor 4. In Figure 3a, the first contact element 7' of the second capacitor 4 is, for example, a negative terminal contact of the capacitor element 2.

[0057] The second electrode layers 6' of the second capacitor 4 are contacted on the second side via a second contact element 8', which rests on the end face of each of the second electrode layers 6' of the second capacitor 4. The end face of the second electrode layer 6' of the second capacitor 4 is the side of the second electrode layer 5' that is located toward the second side, i.e., at the top in Figure 3a. The second contact element 8' of the second capacitor 4 is, for example, welded or soldered to the second electrode layers 6' of the second capacitor 4. The second contact element 8' of the second capacitor 4 thus contacts all second electrode layers 6 of the second capacitor 4. In Figure 3a, the second contact element 8' of the second capacitor 4 is, for example, the center tap of capacitor element 2.

[0058] The first electrode layers 5 and the second electrode layers 6 of the first capacitor 3 are all arranged parallel to the first electrode layers 5' of the second capacitor 4 and the second electrode layers 6' of the second capacitor 4. Thus, all electrode layers 5, 5', 6, 6' of the capacitor element 2 are arranged parallel, but in different planes. The first capacitor 3 is separated and insulated from the second capacitor 4 by an insulating layer 16 of the first capacitor 3 and by an insulating layer 16' of the second capacitor 4.

[0059] In a second embodiment, the first capacitor 3 has a wound structure. A first electrode layer 5 of the first capacitor 3 is wound with a second electrode layer 6 of the first capacitor 3. The first electrode layer 5 of the first capacitor 3 has the same dimensions as the second electrode layer 6 of the first capacitor 3. The first electrode layer 5 of the first capacitor 3 protrudes beyond the second electrode layer 6 of the first capacitor 3 on a first side. The first side is located at the bottom in Figure 3a.Since the first electrode layer 5 of the first capacitor 3 has the same dimensions as the second electrode layer 6 of the first capacitor 3, the second electrode layer 6 of the first capacitor 3 protrudes correspondingly beyond the first electrode layer 5 of the first capacitor 3 on a second side, wherein the second side is a side of the electrode layers 5, 6 of the first capacitor 3 opposite the first side. The second side is thus located at the top in Figure 3a. The electrode layers 5, 6 of the first capacitor 3 are either coated or embedded in a potting compound to prevent a short circuit between the first electrode layer 5 of the first capacitor 3 and the second electrode layer 6 of the first capacitor 3. Alternatively or additionally, an insulating element is arranged between the electrode layers 5, 6 of the first capacitor 3 to insulate them from one another.

[0060] The first electrode layer 5 of the first capacitor 3 is contacted on the first side via a first contact element 7 of the first capacitor 3, which rests on the front side of the first electrode layer 5 of the first capacitor 3. The front side of the first electrode layer 5 of the first capacitor 3 is the side of the first electrode layer 5 that is located toward the first side, i.e., at the bottom in Figure 3a. The first contact element 7 of the first capacitor 3 is, for example, welded or soldered to the first electrode layer 5. In Figure 3a, the first contact element 7 of the first capacitor 3 is, for example, a positive connection contact of the capacitor element 2.

[0061] The second electrode layer 6 of the first capacitor 3 is contacted on the second side via a second contact element 8, which rests on the end face of the second electrode layer 6 of the first capacitor 3. The end face of the second electrode layer 6 of the first capacitor 3 is the side of the second electrode layer 5 which is located towards the second side, i.e., at the top in Figure 3a. The second contact element 8 of the first capacitor 3 is, for example, welded or soldered to the second electrode layer 6 of the first capacitor 3. In Figure 3a, the second contact element 8 of the first capacitor 3 is, for example, the center tap of the capacitor element 2. The second capacitor 4 has a structure corresponding to the first capacitor 3, wherein it is optionally designed to be a mirror image of the first capacitor 3.

[0062] The first electrode layer 5' of the second capacitor 4 is contacted on the first side via a first contact element 7' of the second capacitor 4, which rests on the front side of the first electrode layer 5' of the second capacitor 4. The front side of the first electrode layer 5' of the second capacitor 4 is the side of the first electrode layer 5' that is located toward the first side, i.e., at the bottom in Figure 3a. The first electrode layer 7' of the second capacitor 4 is, for example, welded or soldered to the first electrode layers 5'. The first electrode layer 7' contacts the first electrode layer 5' of the second capacitor 4. In Figure 3a, the first contact element 7' of the second capacitor 4 is, for example, a negative terminal contact of the capacitor element 2.

[0063] The second electrode layer 6' of the second capacitor 4 is contacted on the second side via a second contact element 8', which rests on the end face of the second electrode layer 6' of the second capacitor 4. The end face of the second electrode layer 6' of the second capacitor 4 is the side of the second electrode layer 5' that is located toward the second side, i.e., at the top in Figure 3a. The second electrode layer 8' of the second capacitor 4 is, for example, welded or soldered to the second electrode layer 6' of the second capacitor 4. The second contact element 8' of the second capacitor 4 contacts the second electrode layer 6 of the second capacitor 4. In Figure 3a, the second contact element 8' of the second capacitor 4 is, for example, the center tap of the capacitor element 2.

[0064] The first capacitor 3 is separated and insulated from the second capacitor 4 by an insulation layer 16 of the first capacitor 3 and by an insulation layer 16' of the second capacitor 4.

[0065] For all of the previously described embodiments, the first contact element 7 of the first capacitor 3 and the first contact element 7' of the second capacitor 4 are both arranged on the first side of the capacitor element 2. Thus, the first contact element 7 of the first capacitor 3 and the first contact element 7' of the second capacitor 4 are arranged on a common side of the capacitor arrangement 1. The second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4 are arranged on the second side 4 of the capacitor arrangement 1. Thus, the second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4 are arranged on a common side of the capacitor arrangement 1. The second contact element 8 of the first capacitor 3 is formed integrally with the second contact element 8' of the second capacitor 4.The two second contact elements 8, 8' can thus also be regarded as a single contact element or the second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4 can be regarded as sections of a contact element of the capacitor element 2.

[0066] The second contact elements 8, 8' can be used as the center tap of the capacitor element 2. However, it is advantageous if such a center tap is located on the same side of the capacitor element 2 as its positive and negative terminal contacts, which in Figure 3a are realized by the first contact element 7 of the first capacitor 3 and the first contact element 7' of the second capacitor 4. A corresponding center tap is created by the capacitor elements 2 shown in Figures 3b to 3d.

[0067] Figure 3b shows a capacitor element 2 which essentially corresponds to the capacitor element 2 known from Figure 3a. The capacitor element 2 additionally comprises a first conductor element 9 which is arranged between the first capacitor 3 and the second capacitor 4. The first conductor element 9 has an essentially plate-shaped structure and is arranged in its plate plane parallel to the electrode layers 5, 6, 5', 6' of the capacitor element 2. The first conductor element 9 preferably has a shape which corresponds to an outer wall of the capacitors 3, 4 in order to bear against them in a form-fitting manner. The first conductor element 9 is preferably formed in one piece with the second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4.Thus, the second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4 are connected on the second side to the first conductor element 9, wherein the second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4 together with the first conductor element 9 form a T-shape. The first conductor element 9 extends into a plane on the first side of the capacitor element 2, in which plane the first contact elements 7, 7' of the capacitors 3, 4 are also located. This enables contacting of the second contact elements 8, 8' of the first and second capacitors 3, 4 from the first side of the capacitor element 2 via the first conductor element 9. This enables a center tap from the first side of the capacitor element 2.Such a design of a center tap through the first conductor element 9 also leads to heat dissipation, by which heating caused by the capacitors 3, 4 can be dissipated from the otherwise poorly thermally conductive capacitor windings.

[0068] Figure 3c shows an alternative implementation of a center tap. The capacitor element 2 shown in Figure 3c has essentially the same structure as the capacitor element 2 shown in Figure 3a. However, to enable a center tap from the first side of the capacitor element 2, a second conductor element 10, 10' is arranged on opposite sides of the capacitor element 2. The two second conductor elements 10, 10' thus encompass the capacitor element 2 by being arranged on these opposite sides of the first capacitor 3 and the second capacitor 4.

[0069] The two second conductor elements 10, 10' have a substantially plate-shaped structure and are arranged in their plate plane parallel to the electrode layers 5, 5', 6, 6' of the two capacitors 3, 4 of the capacitor element 2 if the capacitors 3, 4 have a layered structure. If the capacitors 3, 4 have a wound structure, the two second conductor elements 10, 10' extend parallel to a winding axis of the electrode layers 5, 5', 6, 6' of the two capacitors 3, 4.

[0070] The second conductor elements 10, 10' are connected on the second side to the second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4, wherein the second conductor elements 10, 10' are preferably formed integrally with the two second contact elements 8, 8' of the capacitors 3, 4 of the capacitor element 2. Thus, the second contact element 8 of the first capacitor 3 and the second contact element 8' of the second capacitor 4, together with the two second conductor elements 10, 10', form a U-shape. On the first side, the second conductor elements 10, 10' extend into the plane in which the first contact elements 7, 7' are also located. Thus, contacting of the second contact elements 8, 8' is possible via the second conductor elements 10, 10', thus creating a symmetrical center tap.Such an arrangement of the second conductor elements 10, 10' offers, in addition to improved heat dissipation, additional mechanical protection for the capacitors 3, 4 of the capacitor element 2.

[0071] Figure 3d shows a capacitor arrangement 1 which is essentially a combination of the capacitor arrangements 1 shown in Figures 3b and 3c. The capacitor arrangement 1 shown in Figure 3d comprises the first conductor element 9 and the two second conductor elements 10, 10'.

[0072] In the capacitor arrangements 1 described in Figures 3a to 3c, the first contact element 7 of the first capacitor 3 is arranged in a common plane with the first contact element 7' of the second capacitor 4. The second contact element 8 of the first capacitor 3 is also arranged in a common plane with the second contact element 8' of the second capacitor 4.

[0073] Figure 4 shows a capacitor arrangement 1 according to the invention, which comprises a plurality of capacitor elements 2. The capacitor arrangement 1 with a plurality of capacitor elements 2 is in particular a combination of the capacitor elements 2 shown in Figures 3a to 3d. Figure 4 shows, by way of example, a combination of four of the capacitor elements 2 shown in Figure 3c. It should be noted that the second contact elements 8, 8' of all capacitors 4, 5 of all capacitor elements 2 can be formed together in one piece. Depending on the perspective, the capacitor arrangement 1 shown in Figure 4 can also be considered a combination of the capacitor elements 2 shown in Figures 3a and 3c. The capacitor elements 2 of the capacitor arrangement 1 shown in Figure 4 are layered on top of one another.Thus, a stack of individual capacitor elements 2 is created, wherein a number of capacitor elements 2 are arranged directly next to one another, wherein the capacitor elements 2 are arranged in a row.

[0074] The capacitor elements 2 are preferably layered, i.e. arranged next to one another, in such a way that the first capacitors 3 and the second capacitors 4 of the individual capacitor elements 2 are arranged alternately. In Figure 4, a first capacitor 3 is arranged first, then a second capacitor 4, then again a first capacitor 3, followed by a second capacitor 4, and so on. This results in the magnetic fields being compensated to the outside as much as possible and the effective inductance being minimized. The center tap of the capacitor arrangement 1 can be contacted at several points from the first side of the capacitor arrangement 1. The first contact elements 7, 7' of all capacitors 3 can also be contacted from the first side.

[0075] To provide sufficient total capacitance, the capacitor elements 2 are connected together to form a DC link capacitor. The overall DC link thus consists of several capacitor elements 2. Three cells are shown as an example. However, the actual number can be significantly higher. The overall DC link preferably has as many cells as the number of phases of a motor connected to the overall DC link.

[0076] This results in several parallel loops for each commutation case. Each commutation loop has a reduced cross-sectional area because the forward and return paths are close together. This results in a more even current distribution and a lower effective inductance.

[0077] For all capacitor arrangements 1 shown, it applies that they are preferably designed for an operating voltage of more than 50 volts.

[0078] The capacitor arrangement 1 according to the invention is particularly suitable for 3-level inverters requiring a center tap. It is also advantageous for use in chargers for electric vehicles (in-vehicle or as a DC charging station), in drive inverters for electric vehicles with particularly high drive efficiency, and in grid connections for stationary energy storage devices (e.g., accumulators) or energy generators (e.g., fuel cells, photovoltaics).

[0079] In contrast to LIGA capacitors, it is proposed to combine individual capacitor elements (e.g. made of polypropylene films, PET films, PPS films, ceramic layers or in polymer multilayer technology). The structure should still be layered, but not at the electrode level, as this would not be expedient for the desired voltage class (typically 300V-1000V), as higher voltages require larger spacing and careful wiring. The individual layer elements are created by capacitors 3 and 4 and are preferably designed for half the intermediate circuit voltage. The number of layers, i.e. the number of capacitor elements (2), is selected to achieve an optimal compromise between low-inductance design, compact design and wiring complexity. Since each layer is formed from a full-fledged capacitor, a center tap can also be implemented (compared to LIGA).

[0080] A capacitor element 2 preferably comprises an electrode stack with a thickness of 1 mm to 100 mm. Stack heights that are too small result in increased wiring and insulation costs, while stack heights that are too large reduce the advantages of the concept.

[0081] In addition to layered capacitor elements, round windings and, in particular, flat windings pressed into a flat shape (“flat winding”) can also be used.

[0082] Figures 5a and 5b show a plan view of the capacitor arrangement 1 shown in Figure 4. The capacitor arrangement 1 is shown from the perspective of the first contact elements 7, 7' located at the bottom in Figure 4. Figure 5a shows an arrangement of first capacitors 3 and second capacitors 4, which have a shape typical of stacked capacitors. Figure 5b shows an arrangement of first capacitors 3 and second capacitors 4, which have a shape typical of wound capacitors. The capacitors 3, 4 are flattened round coils. Although the use of flattened round coils somewhat reduces the area of ​​parallel plate guidance, this small disadvantage can often be accepted.

[0083] In both cases, it can be seen that the first capacitors 3 can be contacted via the first contact elements 7 of the first capacitors 3 and the second capacitors 4 can be contacted via the second contact elements 7' of the second capacitors 4. At the same time, the second contact elements 8, 8' can be contacted together via a one-piece contact element, which is located behind the capacitors 4, 5 in the image plane of Figures 5a and 5b. The conductor elements 10, 10' shown in Figure 4, which enable the center tap from the first side, are not shown in Figures 5a and 5b.

[0084] Figure 5c shows a capacitor arrangement 1 which essentially corresponds to the capacitor arrangements shown in Figures 5a and 5b, wherein the first capacitors 3 are, however, created from a parallel connection of several round-wound capacitors 17, and wherein the second capacitors 4 are created from a parallel connection of several round-wound capacitors 17. The round-wound capacitors 17 of each first capacitor 3 are each contacted via a common first contact element 7 of the first capacitor 3. The round-wound capacitors of each second capacitor 4 are each contacted via a common first contact element 7' of the second capacitor 4. The winding axes of the round-wound capacitors 17 of the first capacitors 3 are arranged offset in plan view from the winding axes of the round-wound capacitors 17 of the second capacitors 4.The top view here is a view of the plane from the direction in which the winding axes are directed.

[0085] When using circular windings, there is typically no parallelism between the layers of capacitors 3 and 4. Nevertheless, alternating layers of the capacitor elements results in a significant improvement in current distribution and effective inductance.

Claims

Claims 1. Capacitor arrangement (1) comprising a capacitor element (2) which comprises a first capacitor (3) and a second capacitor (4), wherein the first capacitor (3) and the second capacitor (4) each have a layered or wound structure, wherein a first electrode can be contacted via a first contact element on a first side of the respective capacitor (3, 4), wherein a second electrode can be contacted via a second contact element on a second side of the respective capacitor (3, 4), wherein the first contact element (7) of the first capacitor (3) and the first contact element (7') of the second capacitor (4) are arranged on a common side of the capacitor arrangement (1) corresponding to the first side,wherein the second contact element (8) of the first capacitor (3) and the second contact element (8') of the second capacitor (4) are arranged on a common side of the capacitor arrangement (1) corresponding to the second side, and wherein the second contact element (8) of the first capacitor (3) is electrically conductively connected to the second contact element (8') of the second capacitor (4).

2. Capacitor arrangement (1) according to claim 1, wherein the first capacitor (3) and the second capacitor (4) each have at least a first electrode layer (5, 5') and a second electrode layer (6, 6'), wherein the first electrode layer (5, 5') protrudes beyond the second electrode layer (6, 6') on the first side, wherein the second electrode layer (6) protrudes beyond the first electrode layer (5, 5') on the second side, wherein the first electrode layer (5, 5') is contacted on the first side via a first contact element (7, 7') which rests on the end face of the first electrode layer (5, 5'), wherein the second electrode layer (6, 6') is contacted on the second side via a second contact element (8, 8') which rests on the end face of the second electrode layer (6, 6').

3. Capacitor arrangement (1) according to one of the preceding claims, wherein the second contact element (8) of the first capacitor (3) is formed integrally with the second contact element (8') of the second capacitor (4).

4. Capacitor arrangement (1) according to one of the preceding claims, wherein the capacitor element (2) further comprises a first conductor element (9) which is arranged between the first capacitor (3) and the second capacitor (4), is connected on the second side to the second contact element (8) of the first capacitor (3) and the second contact element (8') of the second capacitor (4), and enables contacting of the second contact elements (8, 8') on the first side.

5. Capacitor arrangement (1) according to one of the preceding claims, wherein the capacitor element (2) further comprises two second conductor elements (10, 10') which are arranged on opposite sides of the first capacitor (3) and the second capacitor (4), are connected on the second side to the second contact elements (8) of the first capacitor (3) and the second contact element (8') of the second capacitor (4), and on the first side each enable contacting of the second contact elements (8, 8').

6. Capacitor arrangement (1) according to one of the preceding claims, wherein the first contact element (7) of the first capacitor (3) is arranged in a common plane with the first contact element (7') of the second capacitor (4), and / or wherein the second contact element (8) of the first capacitor (3) is arranged in a common plane with the second contact element (8') of the second capacitor (4).

7. Capacitor arrangement (1) according to one of the preceding claims, wherein the first contact element (7) and the second contact element (8) of the first capacitor (3) are arranged on opposite sides of the first capacitor (3), and wherein the first contact element (7') and the second contact element (8') of the second capacitor (4) are arranged on opposite sides of the second capacitor (4).

8. Capacitor arrangement (1) according to one of the preceding claims, wherein the capacitor arrangement (1) has a plurality of capacitor elements (2), wherein the capacitor elements (2) are preferably arranged such that the first capacitors (3) and the second capacitors (4) of the capacitor elements (2) are arranged alternately.

9. Capacitor arrangement (1) according to claim 8, wherein the capacitor elements (2) are preferably arranged in one plane and the second contact elements (8, 8') of all capacitor elements (2) are formed via a common one-piece contact element.

10. Capacitor arrangement (1) according to one of the preceding claims, wherein the capacitor arrangement (1) is designed for an operating voltage of more than 50 volts.

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