Power converter for an on-board electrical system of an electrically drivable vehicle, and on-board electrical system for an electrically drivable vehicle

Abstract

The filter device (8) includes a first line (2) for a first potential (3), a second line (4) for a second potential (5), a third line (6) for a reference potential (7), first to third terminals (10-12) connected to the first to third lines (2, 4, 6), first and second capacitors (13, 14) having a central node (15) connected to the third terminal (12) formed therebetween, third and fourth capacitors (16, 17) connected between a terminal (13a) of the first capacitor (13) and the first terminal (10) and between a terminal (14b) of the second capacitor (14) and the second terminal (11), and a switching device (19) configured to switch between a first filter mode and a second filter mode based on control information (20), wherein in the first filter mode, a first filter for an interference current is generated. a power converter (1, 1a, 1b) for an on-board electrical system (101) of an electrically drivable vehicle (100), wherein a current path (21) is formed on the first line (2, 4) from the first terminal (10) via the third capacitor (16), the parallel connection of the first and second capacitors (13, 14), and the central node (15) to the third terminal (12), and a second current path (22) for an interference current is formed on the second line from the second terminal (11) via the fourth capacitor (17), the parallel connection of the first and second capacitors (13, 14), and the central node (15) to the third terminal (12), and in a second filter mode, admittances of the interference current along the first current path (21) and the second current path (22) are at least reduced compared to the first filter mode.

Description

[Technical Field]

[0001] The present invention relates to a power converter for an on-board electrical system of an electrically drivable vehicle, the power converter having a first line for a first potential, a second line for a second potential, a third line for a reference potential, and a filter device having a first terminal connected to the first line, a second terminal connected to the second line, a third terminal connected to the third line, a first capacitor and a second capacitor forming a central node therebetween having a conductive connection to the third terminal, and a switching device configured to switch the filter device between a first filter mode and a second filter mode based on control information.

[0002] Furthermore, the present invention relates to an on-board electrical system for an electrically drivable vehicle. [Background technology]

[0003] German Patent Application No. 102017220982 discloses a traction power supply system for an electric or hybrid vehicle. The traction power supply system comprises a high-voltage battery connected to a pulse-controlled inverter via a positive high-voltage line and a negative high-voltage line. Each Y-capacitor is connected to the positive and negative high-voltage lines. Each Y-capacitor is assigned a switching element that can be activated by a control unit based on at least one operating state.

[0004] German Patent Application No. 102021003180 discloses an on-board electrical system for an electrically operable vehicle, which has a line for a first potential and a line for a second potential, between which a DC voltage is applied to the on-board electrical system. The on-board electrical system has two first interference suppression capacitors electrically connected in series and electrically coupled to the potential lines by terminals, respectively. The on-board electrical system also has two further interference suppression capacitors and a switch.

[0005] In electrically driven vehicles, onboard electrical systems, particularly high-voltage onboard electrical systems, are typically designed as IT systems in which the first and second potentials of the traction battery are isolated from a reference potential, particularly the vehicle housing potential. Power converters used in such onboard electrical systems, which may connect their first and second lines to the first and second potentials of the traction battery, may generate high-frequency interference signals during their operation that must be filtered by a filter device for electromagnetic compatibility reasons. Typically, such a filter device includes two capacitors that are used to dissipate common-mode currents on the first and second lines to a third line at the reference potential.

[0006] As the voltage of the onboard electrical system increases, corresponding to the difference between the first and second potentials, the amount of energy stored in the first and second capacitors of the filter device also increases with the square of the voltage of the onboard electrical system. Relevant standards, such as ISO 6469-3, limit this amount of energy to a predefined value. As a result, in the event of an insulation fault, the charge stored in the capacitor and leaking out through the third line, especially during the traction battery charging process, must be kept below limits that are harmful to humans. Therefore, when designing a power converter, the energy budget predefined by the design of the onboard electrical system must be adhered to.

[0007] In fact, it has already been proposed to provide a switch in the current path between the capacitor and the third terminal of the filter device to connect the capacitor to the third terminal or reference potential in the first filter mode and to disconnect it from the third terminal in the second filter mode. However, such a switch has a parasitic capacitance whose size can only be controlled imprecisely due to manufacturing. In the second filter mode, this results in a voltage division across the capacitor and switch that cannot be predicted without difficulty, making it much more difficult to accurately determine the energy budget required to ensure electrical safety. In combination with the additional filter inductance, this can sometimes result in a filter frequency position that can only be predicted very imprecisely. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] German Patent Application Publication No. 102017220982 [Patent Document 2] German Patent Application Publication No. 102021003180 Summary of the Invention [Problem to be solved by the invention]

[0009] The invention is based on the object of specifying improved options for operating power converters in the on-board electrical systems of electrically drivable vehicles. [Means for solving the problem]

[0010] According to the invention, this object is achieved in that in a power converter of the type mentioned at the beginning, the filter device also has a third capacitor connected between a terminal of the first capacitor opposite to the central node and a first terminal of the filter device, and a fourth capacitor connected between a terminal of the second capacitor opposite to the central node and a second terminal of the filter device, wherein in the first filter mode a first current path for the interference current is formed on the first line from the first terminal of the filter device via the third capacitor, the parallel connection of the first and second capacitors, and the central node to the third terminal of the filter device, and a second current path for the interference current is formed on the second line from the second terminal of the filter device via the fourth capacitor, the parallel connection of the first and second capacitors, and the central node to the third terminal of the filter device, and wherein in the second filter mode the admittance of the interference current along the first and second current paths is at least reduced compared to the first filter mode.

[0011] A power converter according to the present invention has a first line for a first potential, a second line for a second potential, and a third line for a reference potential. The power converter further includes a filter device. The filter device has a first terminal, a second terminal, and a third terminal. The first terminal is connected to the first line. The second terminal is connected to the second line. The third terminal is connected to the third line. The filter device further includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor. A central node is formed between the first capacitor and the second capacitor, the central node having a conductive connection to the third terminal. The third capacitor is connected between a terminal of the first capacitor opposite the central node and the first terminal of the filter device. The fourth capacitor is connected between a terminal of the second capacitor opposite the central node and the second terminal of the filter device. The filter device further includes a switching device. The switching device is configured to switch the filter device between a first filter mode and a second filter mode based on control information. In the first filter mode, a first current path for the interference current is formed on the first line from the first terminal of the filter device through the third capacitor, the parallel connection of the first capacitor and the second capacitor, and the central node to the third terminal of the filter device. In the first filter mode, a second current path for the interference current is also formed on the second line from the second terminal of the filter device through the fourth capacitor, the parallel connection of the first capacitor and the second capacitor, and the central node to the third connection of the filter device. In the second filter mode, the admittance of the interference current along the first and second current paths is at least reduced compared to the first filter mode.

[0012] In the power converter according to the present invention, the first and second current paths in the first filter mode are routed through a parallel connection of the first and second capacitors. This parallel connection advantageously forms a distinct capacitance between the third and fourth capacitors and the third terminal, thereby enabling accurate determination of the energy budget when designing the power converter. As an additional advantage, the capacitor network forms an X capacitance in the first filter mode, which enables stronger suppression of opposite-mode interference. In the second filter mode, the effective Y capacitance is substantially dominated by the series connection of the first and third capacitors or the series connection of the second and fourth capacitors due to reduced admittance. This allows for a significant reduction in the Y capacitance in the second filter mode, which reduces energy budget constraints and enables more accurate determination of the energy budget when designing the power converter compared to conventional filter devices.

[0013] The power converter according to the present invention may be designed as an inverter, a DC / DC voltage converter, or an active rectifier. The power converter according to the present invention may further comprise a housing in which at least the first line, the second line, the third line, and the filter device are accommodated. The third line may be conductively connected to the housing. In this respect, the reference potential may also be considered as the housing potential.

[0014] The first potential is typically different from the second potential. Preferably, the first potential is greater than the second potential. The reference potential is preferably between the first potential and the second potential. The reference potential may also be considered as a ground potential. In one preferred configuration, the first line and the second line are each formed completely or at least partially as a solid busbar. The first and second lines may be connected to DC voltage terminals of the power converter, at which a connection device is formed, in particular for electrically contacting the power converter with a DC voltage source. The filter device is preferably arranged on the DC voltage terminal side. The interference current is particularly a common mode current or includes a common mode current.

[0015] The third line does not necessarily have to be formed as a busbar, but may also be formed by a cable, a ground plane or a fixing means by means of which the filter device is fixed to the power converter, in particular to the housing.

[0016] The first, second, third and fourth capacitors may each have a first terminal and a second terminal between which the capacitance of the capacitor is provided. The first terminal of the third capacitor may be connected to the first terminal of the filter device. The second terminal of the fourth capacitor may be connected to the second terminal of the filter device.

[0017] The first, second, third and fourth capacitors may each be formed by one capacitor component or by several interconnected capacitor components. The switching device is preferably a semiconductor switching device, in particular having one or more transistor structures. Alternatively, the switching device can be an electromechanical switching device, for example having one or more relays.

[0018] Preferably, the filter device of the power converter according to the invention is configured in the second filter mode to set a higher pole frequency and / or a lower effective total capacitance than in the first filter mode in order to filter interference currents between the first and third terminals and between the second and third terminals, so that in the event of a first insulation fault, the discharge time constant due to the active effective Y capacitance and resulting body resistance can thereby be advantageously modified.

[0019] In the power converter according to the present invention, in the second filter mode, the admittance along the first current path between the third capacitor and the second capacitor can be reduced at least compared to the first filter mode, and the admittance along the second current path between the fourth capacitor and the first capacitor can be reduced at least compared to the first filter mode.

[0020] However, it is particularly preferred if, in the second filter mode, the first current path is interrupted in the circuit branch between the third capacitor and the second capacitor and the second current path is interrupted in the circuit branch between the fourth capacitor and the first capacitor, so that the Y capacitance can be reduced particularly sharply in the second filter mode, since it is smaller than the minimum capacitance of the series connection in each case where the first capacitor and the third capacitor are connected in series on the one hand and where the second capacitor and the fourth capacitor are connected in series on the other hand.

[0021] In particular, in the second filter mode, the capacitance of the circuit branch connecting the first terminal and the central node can correspond to the reciprocal of the sum of the reciprocals of the capacitances of the first capacitor and the third capacitor, and the capacitance of the circuit branch connecting the second terminal and the central node can correspond to the reciprocal of the sum of the reciprocals of the capacitances of the second capacitor and the fourth capacitor.

[0022] Furthermore, in the first filter mode, the capacitance of the circuit branch connecting the third and fourth capacitors to the third terminal may correspond to the sum of the capacitances of the first and second capacitors.

[0023] In one preferred configuration of the power converter according to the invention, it is provided that the central node is a common node of the third terminal of the filter device, a terminal of the first capacitor opposite to the third capacitor and / or facing the second capacitor, and a terminal of the second capacitor opposite to the fourth terminal and / or facing the first capacitor. The terminal of the first capacitor opposite to the third terminal and / or facing the second capacitor may correspond to the second terminal of the first capacitor. The terminal of the second capacitor opposite to the fourth terminal and / or facing the first capacitor may correspond to the first terminal of the second capacitor.

[0024] The first terminal of the first capacitor may be connected to the second terminal of the third capacitor, and the second terminal of the second capacitor may be connected to the first terminal of the fourth capacitor.

[0025] The central node is preferably connected to a third terminal of the filter device.

[0026] In the power converter according to the present invention, it is further preferred that the switching device has a first terminal, a second terminal, and a switching path that can be controlled based on the control information.

[0027] The first terminal of the switching device may have a common node with the first capacitor and the third capacitor. The second terminal of the third capacitor may be connected to the first terminal of the switching device. The first terminal of the first capacitor may be connected to the first terminal of the switching device.

[0028] Alternatively or additionally, the second terminal of the switching device may have a common node with the second capacitor and the fourth capacitor, the second terminal of the second capacitor may be connected to the second terminal of the switching device, and the first terminal of the fourth capacitor may be connected to the second terminal of the switching device.

[0029] In a preferred arrangement, the switching device is configured to switch on the switching path to adopt the first filter mode and / or switch off the switching path to adopt the second filter mode.

[0030] With regard to the dimensions of the capacitances of the power converter according to the invention, it is preferred that the capacitances of the first and fourth capacitors are smaller than the capacitances of the second and third capacitors, in particular at most half, in particular at most five times smaller. Alternatively, the capacitances of the first and fourth capacitors can be larger than the capacitances of the second and third capacitors, in particular at least two times, in particular at least five times larger.

[0031] The capacitances of the first capacitor and the fourth capacitor may also be the same, and the capacitances of the second capacitor and the third capacitor may also be the same.

[0032] To also enable efficient suppression of opposite-mode interference in the second filter mode and to compensate for asymmetry in the case of different capacitance values, the filter device may further comprise a fifth capacitor connected in parallel with the first to fourth capacitors to the first and second terminals of the filter device. In other words, the fifth capacitor may provide a fixed X capacitance. In particular, the fifth capacitor has a capacitance that is at least five times, preferably ten times, greater than the maximum capacitance of the first to fourth capacitors.

[0033] The power converter according to the invention may further be provided that the fourth terminal of the filter device is the first terminal of the filter device or is connected to the first line, the fifth terminal of the filter device is the second terminal of the filter device or is connected to the second line, and the sixth terminal of the filter device is the third terminal of the filter device or is connected to the third line. In a preferred development, it can be provided that the filter device further comprises a sixth capacitor and a seventh capacitor between which a second central node having a conductive connection to the sixth terminal is formed, an eighth capacitor connected between a terminal of the sixth capacitor opposite to the second central node and the fourth terminal of the filter device, a ninth capacitor connected between a terminal of the seventh capacitor opposite to the second central node and the fifth terminal of the filter device, and a second switching device configured to switch the filter device between the first filter mode and the second filter mode based on the control information. A third current path for the interference current may be formed on the first line from the fourth terminal of the filter device through the eighth capacitor, the parallel connection of the sixth and seventh capacitors, and the second central node to the sixth terminal of the filter device. A fourth current path for the interference current may be formed on the second line from the fifth terminal of the filter device through the ninth capacitor, the parallel connection of the sixth and seventh capacitors, and the second central node to the sixth terminal of the filter device. In the second filter mode, the admittance of the interference current along the third and fourth current paths may be at least reduced compared to the first filter mode. By providing a second group of four capacitors, i.e., the sixth through ninth capacitors, connected in parallel with the first through fourth capacitors, further balancing of the current distribution within the filter device may be achieved.

[0034] In a preferred embodiment, when the capacitances of the first and fourth capacitors are smaller than those of the second and third capacitors, the capacitances of the sixth and ninth capacitors can be greater than those of the seventh and eighth capacitors, particularly at least twice as large, particularly at least five times larger. Alternatively, when the capacitances of the first and fourth capacitors are greater than those of the second and third capacitors, the capacitances of the sixth and ninth capacitors can be smaller than those of the seventh and eighth capacitors, particularly at most half as large, particularly at most five times smaller. Thus, the capacitance ratio of the second group can be reversed with respect to the first group including the first to fourth capacitors. In particular, the capacitances of the first, fourth, seventh, and eighth capacitors can be identical, and / or the capacitances of the second, third, sixth, and ninth capacitors can be identical.

[0035] Furthermore, all descriptions relating to the first through fourth capacitors can be transferred to the sixth through ninth capacitors, and all descriptions relating to the first switching device can be transferred to the second switching device. Thus, the following may particularly apply: The sixth, seventh, eighth, and ninth capacitors may each have a first terminal and a second terminal between which the capacitance of the capacitor is provided. The first terminal of the eighth capacitor may be connected to the fourth terminal of the filter device. The second terminal of the ninth capacitor may be connected to the fifth terminal of the filter device.

[0036] The sixth, seventh, eighth and ninth capacitors may each be formed by one capacitor component or by a plurality of interconnected capacitor components. The second switching device is preferably a semiconductor switching device, in particular having one or more transistor structures. Alternatively, the second switching device can be an electromechanical switching device, for example having one or more relays.

[0037] Preferably, in the second filter mode, the filter device is configured to set a higher pole frequency and / or a lower effective total capacitance than in the first filter mode to filter interference currents between the fourth terminal and the sixth terminal and between the fifth terminal and the sixth terminal.

[0038] In the second filter mode, the admittance along the third current path between the eighth capacitor and the seventh capacitor can be at least reduced compared to the first filter mode, and the admittance along the fourth current path between the ninth capacitor and the sixth capacitor can be at least reduced compared to the first filter mode.

[0039] However, in the second filter mode, it is particularly preferred if the third current path is interrupted in the circuit branch between the eighth and seventh capacitors and the fourth current path is interrupted in the circuit branch between the ninth and sixth capacitors.

[0040] In particular, in the second filter mode, the capacitance of the circuit branch connecting the fourth terminal and the second central node can correspond to the reciprocal of the sum of the reciprocals of the capacitances of the sixth capacitor and the eighth capacitor, and the capacitance of the circuit branch connecting the fifth terminal and the second central node can correspond to the reciprocal of the sum of the reciprocals of the capacitances of the seventh capacitor and the ninth capacitor.

[0041] Furthermore, in the first filter mode, the capacitance of the circuit branch connecting the eighth and ninth capacitors to the sixth terminal may correspond to the sum of the capacitances of the sixth and seventh capacitors.

[0042] In one preferred configuration, it is provided that the second central node is a common node of the sixth terminal of the filter device, a terminal of the sixth capacitor opposite to the eighth capacitor and / or facing the seventh capacitor, and a terminal of the seventh capacitor opposite to the ninth terminal and / or facing the sixth capacitor. The terminal of the sixth capacitor opposite to the eighth terminal and / or facing the seventh capacitor may correspond to the second terminal of the sixth capacitor. The terminal of the seventh capacitor opposite to the ninth capacitor and / or facing the sixth capacitor may correspond to the first terminal of the seventh capacitor.

[0043] The first terminal of the sixth capacitor may be connected to the second terminal of the eighth capacitor, and the second terminal of the seventh capacitor may be connected to the first terminal of the ninth capacitor.

[0044] The second central node is preferably connected to the sixth terminal of the filter device.

[0045] The second switching device may have a first terminal, a second terminal, and a switching path that can be controlled according to the control information.

[0046] The first terminal of the second switching device may have a common node with the sixth and eighth capacitors. The second terminal of the eighth capacitor may be connected to the first terminal of the second switching device. The first terminal of the sixth capacitor may be connected to the first terminal of the second switching device.

[0047] Alternatively or additionally, the second terminal of the second switching device may have a common node with the seventh and ninth capacitors. The second terminal of the seventh capacitor may be connected to the second terminal of the second switching device. The first terminal of the ninth capacitor may be connected to the second terminal of the second switching device.

[0048] In a preferred arrangement, the second switching device is configured to switch on the switching path to adopt the first filter mode and / or to switch off the switching path to adopt the second filter mode.

[0049] In one preferred configuration of the power converter according to the present invention, the filter device has a printed circuit board. The first to fourth capacitors may be arranged on the printed circuit board. The fifth capacitor may also be arranged on the printed circuit board. The sixth to ninth capacitors may also be arranged on the printed circuit board. The first to third terminals of the filter device may also be arranged on the printed circuit board. The first switching device may also be arranged on the printed circuit board. The second switching device may also be arranged on the printed circuit board.

[0050] The power converter according to the present invention may further comprise a DC link capacitor connected between the first line and the second line. The DC link capacitor may have a capacitance at least 100 times, preferably 500 times, greater than the largest capacitance of the first to fourth capacitors. The capacitance of the DC link capacitor is typically greater than the capacitance of the fifth capacitor, in particular at least 10 times, preferably at least 50 times greater.

[0051] The power converter according to the invention may further comprise a converter circuit connected between the first and second lines. The converter circuit may comprise power semiconductor switches interconnected in particular as a switching cell, a power bridge or a B6 bridge circuit for converting the voltage present between the first and second lines in switching mode. The filter device is preferably arranged on the side of the DC link capacitor opposite the converter circuit.

[0052] The power converter according to the invention may further comprise inductive filter elements acting as longitudinal inductances in the first and second lines and arranged in particular physical proximity to the DC link capacitor side and / or the DC voltage input side of the filter device, the filter elements being formed around the lines by ferrite cores, e.g. nanocrystalline cores, iron powder cores or other cores made from magnetic material.

[0053] Preferably, the parasitic inductance along the first and second lines between the DC voltage terminals and the first and second terminals of the filter device or the filter elements on the DC voltage terminal side is smaller than the parasitic inductance between the first and second terminals of the filter device or the filter elements on the DC link capacitor side and the DC link capacitor.

[0054] The object on which the invention is based is further achieved by an on-board electrical system for an electrically drivable vehicle, comprising at least one power converter as described above, a traction battery, a charging device connectable to a power supply system external to the vehicle for charging or discharging the traction battery, and a control device configured to provide control information for adopting the second filter mode when and / or as long as the charging device is connected to the power supply system external to the vehicle.

[0055] It is therefore advantageously possible to predefine a filter mode in an operating mode and a second filter mode in a charging mode of the vehicle or on-board electrical system.

[0056] The traction battery preferably has a nominal voltage of at least 400 volts, preferably at least 600 volts, particularly preferably at least 800 volts.

[0057] The power converter of the on-board electrical system may be designed as an inverter configured to power an electric machine, in particular a permanently or electrically excited synchronous machine, an axial flux motor, or an asynchronous machine, by means of a polyphase AC voltage in order to drive the vehicle.

[0058] The power converter of the on-board electrical system may form part of the charging device and may be configured to convert a DC or AC voltage provided by a power supply system external to the vehicle into a DC voltage for charging the traction battery.

[0059] The power converter of the on-board electrical system may be designed as a DC / DC voltage converter configured to couple the on-board electrical system to a further on-board electrical system of the vehicle, in particular a low-voltage on-board electrical system, the potential of which may correspond to a reference potential.

[0060] The on-board electrical system may further include an electrical wire, such as a conductive fastener or a ground strip, by which the third line of the at least one power converter is conductively connected to the body of the vehicle.

[0061] Further advantages and details of the invention can be found in the exemplary embodiments described below on the basis of the drawings, which are schematic diagrams. [Brief explanation of the drawings]

[0062] [Figure 1] 1 is a circuit diagram of an exemplary embodiment of a power converter according to the present invention; [Figure 2] 4 is an equivalent circuit diagram of a filter device in a first filter mode according to an exemplary embodiment. [Figure 3] FIG. 4 is an equivalent circuit diagram of a filter device in a second filter mode, according to an exemplary embodiment. [Figure 4] 1 is a schematic diagram of a power converter in accordance with an exemplary embodiment; [Figure 5] 4 is a circuit diagram of a filter device according to a second exemplary embodiment of a power converter according to the present invention; [Figure 6] FIG. 10 is a circuit diagram of a filter device according to a third exemplary embodiment of a power converter according to the present invention. [Figure 7] 1 is a block diagram of one exemplary embodiment of an on-board electrical system according to the present invention in a vehicle; DETAILED DESCRIPTION OF THE INVENTION

[0063] FIG. 1 is a circuit diagram of an exemplary embodiment of a power converter 1 .

[0064] The power converter 1 has a first line 2 for a first potential 3, a second line 4 for a second potential 5, and a third line 6 for a reference potential 7, which may also be considered ground potential. By way of example, the first potential 3 is higher than the second potential 5, and the power converter 1 is configured to operate with a potential difference of 800 volts between the first potential 3 and the second potential 5. The reference potential 7 is by way of example between the first potential 3 and the second potential 5.

[0065] The power converter 1 also comprises a filter device 8. In particular, the filter device 8 is an interference suppression filter, i.e., for improving the electromagnetic compatibility of the power converter 1, and is preferably arranged in the vicinity of the DC voltage terminals 9.

[0066] The filter device 8 has a first terminal 10 connected to the first line 2, a second terminal 11 connected to the second line 4, and a third terminal 12 connected to the third line 6. The filter device further has a first capacitor 13 and a second capacitor 14 formed therebetween with a central node 15 having a conductive connection to the third terminal 12. The filter device 8 further has a third capacitor 16 and a fourth capacitor 17, where first terminals of the capacitors 13, 14, 16, and 17 are labeled 13a, 14a, 16a, and 17a, and second terminals of the capacitors 13, 14, 16, and 17 are labeled 13b, 14b, 16b, and 17b.

[0067] The third capacitor 16 is connected between a first terminal 13a of the first capacitor 13 opposite the central node 15 and the first terminal 10 of the filter device 8. The fourth capacitor 17 is connected between a second terminal 14b of the second capacitor 14 opposite the central node 15 and the second terminal 11 of the filter device 8.

[0068] The filter device 8 further includes a switching device 19. The switching device 19 is configured to switch between a first filter mode and a second filter mode based on control information 20. In the first filter mode, a first current path 21 for the interference current is formed on the first line 2 from the first terminal 10, the third capacitor 16, the parallel connection of the first capacitor 13 and the second capacitor 14, and the central node 15 to the third terminal 12. In the first filter mode, a second current path 22 for the interference current is also formed on the second line 4 from the second terminal 11 via the fourth capacitor 17, the parallel connection of the first capacitor 13 and the second capacitor 14, and the central node 15 to the third terminal 12. In the second filter mode, the admittance of the interference current along the first current path 21 and the second current path 22 is reduced compared to the first filter mode. The current paths 21 and 22 are shown purely schematically in FIG. 1 by dashed lines.

[0069] In this exemplary embodiment, in the second filter mode, the current paths 21 and 22 are each partially interrupted. The interruption of the first current path 21 is provided in the circuit branch between the third capacitor 16 and the second capacitor 14. The interruption of the second current path 22 is provided in the circuit branch between the fourth capacitor 17 and the first capacitor 13.

[0070] 2 and 3 are equivalent circuit diagrams of the filter device 8, respectively, with FIG. 2 showing the first filter mode and FIG. 3 showing the second filter mode.

[0071] In the first filter mode, the first capacitor 13 and the second capacitor 14 are connected in parallel, so that the capacitance C1 of the first capacitor 13 and the capacitance C2 of the second capacitor 14 sum to form a total capacitance between the central node 15 and a circuit node 23, which is located between the third capacitor 16 and the fourth capacitor 17 in the equivalent circuit diagram. The capacitance C3 of the third capacitor 16 acts in a circuit branch 24 between the circuit node 23 and the first terminal 10 of the filter device 8. The capacitance C4 of the fourth capacitor 17 acts in a circuit branch 25 between the circuit node 23 and the second terminal 11 of the filter device 8. The capacitor network thus formed in the first filter mode provides both a Y capacitance for filtering common-mode interference and an X capacitance for filtering opposite-mode interference.

[0072] In the second filter mode, the first capacitor 13 and the third capacitor 16 are connected in series in a circuit branch 26 between the first terminal 10 and the central node 15 of the filter device 8. Accordingly, in the second filter mode, the second capacitor 14 and the fourth capacitor 17 are also connected in series in a circuit branch 27 between the second terminal 11 and the central node 15 of the filter device 8. Thus, in the second filter mode, a Y capacitance acts in the circuit branches 26, 27, the Y capacitance in the circuit branch 26 being the reciprocal of the sum of the reciprocals of C1 and C3, and the Y capacitance in the circuit branch 27 being the reciprocal of the sum of the reciprocals of C2 and C4. This means that the Y capacitance in each of the circuit branches 26, 27 is smaller than the smallest capacitance in the corresponding circuit branch 26, 27.

[0073] 1 , filter device 8 is realized with respect to the circuit of this exemplary embodiment, in particular in that central node 15 is a common node of third terminal 12 of filter device 8, second terminal 13b of first capacitor 13 facing second capacitor 14 on the opposite side from third capacitor 16, and first terminal 14a of second capacitor 14 facing first capacitor 13 on the opposite side from fourth capacitor 17. Central node 15 is connected to third terminal 12 of filter device 8.

[0074] The switching device 19 has a first terminal 19a, a second terminal 19b, and a switching path formed between the terminals 19a and 19b and controllable based on control information 20. The first terminal 19a of the switching device 19 has a node common to the first capacitor 13 and the third capacitor 16. The first terminal 19a of the switching device 19 is connected to the first terminal 13a of the first capacitor 13 and the second terminal 16b of the third capacitor 16. The second terminal 19b of the switching device 19 has a node common to the second capacitor 14 and the fourth capacitor 17. The second terminal 19b of the switching device 19 is connected to the second terminal 14b of the second capacitor 14 and the first terminal 17a of the fourth capacitor 17. The switching device 19 is configured to switch the switching path on to employ a first filter mode and to switch the switching path off to employ a second filter mode.

[0075] In this exemplary embodiment, the first terminal 16a of the third capacitor 16 is further connected to the first terminal 10 of the filter device 8. The second terminal 16b of the third capacitor 16 is connected to the first terminal 13a of the first capacitor 13. The second terminal 13b of the first capacitor 13 is connected to the first terminal 14a of the second capacitor and the third terminal 12 of the filter device 8. The first terminal 14a of the second capacitor 14 is connected to the second terminal 13b of the first capacitor 13 and the third terminal 12 of the filter device 8. The second terminal 14b of the second capacitor 14 is connected to the first terminal 17a of the fourth capacitor 17. The second terminal 17b of the fourth capacitor 17 is connected to the second terminal 11 of the filter device 8.

[0076] In this exemplary embodiment, a fifth capacitor 28 having a first terminal 28a and a second terminal 28b is further provided. The fifth capacitor 28 is connected in parallel with the first through fourth capacitors 13, 14, 16, and 17 to the first terminal 10 of the filter device 8 and the second terminal 11 of the filter device 8. In this case, the first terminal 10 of the filter device 8, the first terminal 16a of the third capacitor 16, and the first terminal 28a of the fifth capacitor 28 form a common circuit node. Furthermore, the second terminal 11 of the filter device 8, the first terminal 17b of the fourth capacitor 17, and the second terminal 28b of the fifth capacitor 28 form a common circuit node. The fifth capacitor 28 provides a fixed X capacitance.

[0077] In this exemplary embodiment, the capacitances C1 and C4 are equal and smaller than the capacitances C2 and C3, which are also equal. The capacitance C5 of the fifth capacitor 28 is greater than the capacitances C2 and C3. Exemplary capacitance values are C1=C4=20 nF, C2=C3=100 nF, and C5=1 μF. According to an alternative exemplary embodiment, the capacitances C1 and C4 are equal and larger than the capacitances C2 and C3, which are also equal. For example, in that case, C1=C4=100 nF, C2=C3=20 nF, and C5=1 μF.

[0078] 1 further shows a DC link capacitor 40 connected between the first line 2 and the second line 4, the DC link capacitor 40 having a capacitance of at least 50 μF, and a converter circuit 41 connected between the first line 2 and the second line 4. It can be seen that the filter device 8 is arranged on the opposite side of the DC link capacitor 40 from the converter circuit 41.

[0079] The power converter 1 further comprises four inductive filter elements 42, 43, 44, 45, which act as longitudinal inductances in the lines 2, 4 and are formed around the lines 2, 4 by, for example, ferrite cores, such as nanocrystalline cores, iron powder cores, or other cores made of magnetic material. The filter elements 42 to 45 are arranged in close proximity to the filter device 8. The filter elements 42, 44 are arranged on the DC voltage input side relative to the filter device 8. The filter elements 43, 45 are arranged on the DC link capacitor side relative to the filter device 8.

[0080] FIG. 1 shows the parasitic inductances L along the first line 2 and second line 4 between the DC voltage terminal 9 and the filter device 8 and the filter elements 42, 44, respectively. 1p , L 1n , and the parasitic inductance L along the first line 2 and the second line 4, respectively, between the filter device 8 and the filter elements 43, 45 and the DC link capacitor 40. 2p , L 2n In this case, the arrangement of the filter device 8 is such that it is possible to filter as efficiently as possible. 1p and L 1n L 2p and L 2n It is preferably selected to be smaller than

[0081] FIG. 4 is a schematic diagram of a power converter 1 according to an example embodiment.

[0082] The filter device 8 comprises a printed circuit board 50 on which terminals 10, 11, 12, capacitors 13, 14, 16, 17, 28 and a switching device 19 are arranged. The first line 2 and the second line 4 are formed by solid busbars 51, 52, respectively, which contact terminals 10, 11 on the printed circuit board 50. A DC voltage terminal 9, formed as a connection device 53, is connected to first ends of the busbars 51, 52. A converter circuit 41 is connected to second ends of the busbars 51, 52. A DC link capacitor 40 is also in contact with the busbars 51, 52 and is located closer to the converter circuit 41 than the filter device 8, relative to the length of the busbar 51.

[0083] The third terminal 12 of the filter device 8 is not in contact with the busbars 51, 52 but is connected to the housing 55 of the power converter 1 by fastening means 54 forming a third line 6. The reference potential 7 may therefore also be considered as the housing potential. The lines 2, 4 or busbars 51, 52, the filter device 8, the DC link capacitor 40 and the converter circuit 41 are accommodated in the housing 55.

[0084] The power converter 1 may be designed as an inverter, a DC / DC voltage converter or an active rectifier, and the converter circuit 41 comprises semiconductor switching elements suitable for this purpose.

[0085] 5 is a circuit diagram of a filter device 8 according to a second exemplary embodiment of the power converter 1. All details of the first exemplary embodiment can be transferred to the second exemplary embodiment unless otherwise stated below. Identical or functionally equivalent components are provided with the same reference numerals.

[0086] According to the second exemplary embodiment, the filter device 8 further comprises a sixth capacitor 63 and a seventh capacitor 64 having a second central node 65 formed therebetween with a conductive connection to the third terminal 12. The filter device 8 further comprises an eighth capacitor 66 and a ninth capacitor 67, wherein first terminals of the capacitors 63, 64, 66, 67 are labeled 63a, 64a, 66a, 67a, and second terminals of the capacitors 63, 64, 66, 67 are labeled 63b, 64b, 66b, 67b.

[0087] The eighth capacitor 66 is connected between a first terminal 63a of the sixth capacitor 63 opposite the second central node 65 and a first terminal 10 of the filter device 8. The ninth capacitor 67 is connected between a second terminal 64b of the seventh capacitor 64 opposite the second central node 65 and a second terminal 11 of the filter device 8.

[0088] The filter device 8 further includes a second switching device 69. The second switching device 69 is configured to switch between the first and second filter modes based on the control information 20. In the first filter mode, a third current path 71 for the interference current is formed on the first line 2 from the first terminal 10, the eighth capacitor 66, the parallel connection of the sixth capacitor 63 and the seventh capacitor 64, and the second central node 65 to the third terminal 12. In the first filter mode, a fourth current path 72 for the interference current is also formed on the second line 4 from the second terminal 11 through the ninth capacitor 67, the parallel connection of the sixth capacitor 63 and the seventh capacitor 64, and the second central node 65 to the third terminal 12. In the second filter mode, the admittance of the interference current along the third current path 71 and the fourth current path 72 is reduced compared to the first filter mode. The current paths 21, 22, 71, and 72 are shown purely schematically in FIG. 5 by dashed lines.

[0089] In the second exemplary embodiment, in the second filter mode, the current paths 71, 72 are each partially interrupted. The interruption of the third current path 71 is provided in the circuit branch between the eighth capacitor 66 and the seventh capacitor 64. The interruption of the fourth current path 72 is provided in the circuit branch between the ninth capacitor 67 and the sixth capacitor 63.

[0090] In the first filter mode, the sixth capacitor 63 and the seventh capacitor 64 are connected in parallel, so that the capacitance C6 of the sixth capacitor 63 and the capacitance C7 of the seventh capacitor 64 add up to a total capacitance between the circuit node between the eighth capacitor 66 and the ninth capacitor 67 and the second central node 65, similar to the circuit node 23 in the equivalent circuit diagram according to Fig. 2. The capacitance C8 of the eighth capacitor 66 acts in the circuit branch between the circuit node corresponding to the circuit node 23 and the first terminal 10 of the filter device 8, corresponding to the circuit branch 24 according to Fig. 2. The capacitance C9 of the ninth capacitor 67 acts in the circuit branch between the circuit node corresponding to the circuit node 23 and the second terminal 11 of the filter device 8, corresponding to the circuit branch 25 according to Fig. 2. The capacitor network of the sixth to ninth capacitors 63, 64, 66, 67 thus formed in the first filter mode provides both a Y capacitance for filtering common-mode interference and an X capacitance for filtering opposite-mode interference.

[0091] In the second filter mode, the sixth capacitor 63 and the eighth capacitor 66 are connected in series in a circuit branch 76 between the first terminal 10 of the filter device 8 and the second central node 65. Accordingly, in the second filter mode, the seventh capacitor 64 and the ninth capacitor 67 are also connected in series in a circuit branch 77 between the second terminal 11 of the filter device 8 and the second central node 65. Thus, in the second filter mode, a Y capacitance acts on the circuit branches 76, 77, and the Y capacitance in the circuit branch 76 is the reciprocal of the sum of the reciprocals of C6 and C8, and the Y capacitance in the circuit branch 77 is the reciprocal of the sum of the reciprocals of C7 and C9. This means that the Y capacitance in each of the circuit branches 76, 77 is smaller than the smallest capacitance in the corresponding circuit branch 76, 77.

[0092] The second central node 65 is a common node between the third terminal 12 of the filter device 8, a second terminal 63b of the sixth capacitor 63 facing the seventh capacitor 64 on the opposite side to the eighth capacitor 66, and a first terminal 64a of the seventh capacitor 64 facing the sixth capacitor 63 on the opposite side to the ninth capacitor 67. The second central node 65 is connected to the third terminal 12 of the filter device 8.

[0093] The second switching device 69 has a first terminal 69a, a second terminal 69b, and a switching path formed between the terminals 69a and 69b and controllable based on control information 20. The first terminal 69a of the switching device 69 has a common node with the sixth capacitor 63 and the eighth capacitor 66. The first terminal 69a of the second switching device 69 is connected to the first terminal 63a of the sixth capacitor 63 and the second terminal 66b of the eighth capacitor 66. The second terminal 69b of the second switching device 69 has a common node with the seventh capacitor 64 and the ninth capacitor 67. The second terminal 69b of the second switching device 69 is connected to the second terminal 64b of the seventh capacitor 64 and the first terminal 67a of the ninth capacitor 67. The second switching device 69 is configured to switch the switching path on to employ the first filter mode and to switch the switching path off to employ the second filter mode.

[0094] The first terminal 66a of the eighth capacitor 66 is connected to the first terminal 10 of the filter device 8. The second terminal 66b of the eighth capacitor 66 is connected to the first terminal 53a of the sixth capacitor 63. The second terminal 63b of the sixth capacitor 63 is connected to the first terminal 64a of the seventh capacitor 64 and the third terminal 12 of the filter device 8. The first terminal 64a of the seventh capacitor 64 is connected to the second terminal 63b of the sixth capacitor 63 and the third terminal 12 of the filter device 8. The second terminal 64b of the seventh capacitor 64 is connected to the first terminal 67a of the ninth capacitor 67. The second terminal 67b of the ninth capacitor 67 is connected to the second terminal 11 of the filter device 8.

[0095] In this exemplary embodiment, capacitances C6 and C9 are the same, and capacitances C7 and C8 are the same. If capacitances C1 and C4 are larger than capacitances C2 and C3, capacitances C6 and C9 are smaller than capacitances C7 and C8. If capacitances C1 and C4 are smaller than capacitances C2 and C3, capacitances C6 and C9 are larger than capacitances C7 and C8. In particular, capacitances C1, C4, C7, and C8 are the same, and capacitances C2, C3, C6, and C9 are the same.

[0096] In the second exemplary embodiment, sixth to ninth capacitors 63, 64, 66, 67 and a second switching device 69 are also disposed on the printed circuit board 50 (see FIG. 4).

[0097] FIG. 6 shows a circuit diagram of a filter device 8 according to a third exemplary embodiment of a power converter 1, which corresponds to the second exemplary embodiment except for the following differences.

[0098] According to a third exemplary embodiment, the filter device 8 further comprises a fourth terminal 60 connected to the first line 2, a fifth terminal 61 connected to the second line 4 and a sixth terminal 62 connected to the third line 6. In this case, it is assumed that: The second central node 65 has a conductive connection to the sixth connection 12 of the filter device 8. The eighth capacitor 66 is connected between the first terminal 63a of the sixth capacitor 63 and the fourth terminal 60 of the filter device 8. The ninth capacitor 67 is connected between the second terminal 64b of the seventh capacitor 64 and the fifth terminal 61 of the filter device 8. A third current path 71 extends from the fourth terminal 60 through the eighth capacitor 66, the parallel connection of the sixth capacitor 63 and the seventh capacitor 64, and the second central node 65 to the sixth terminal 62. A fourth current path 72 extends from the fifth terminal 61 through the ninth capacitor 67, the parallel connection of the sixth capacitor 63 and the seventh capacitor 64, and the second central node 65 to the sixth terminal 62.

[0099] In the first filter mode, the capacitor C8 acts in the circuit branch between the circuit node corresponding to the circuit node 23 and the fourth terminal 60, which corresponds to the circuit branch 24 according to Fig. 2. The capacitor C9 acts in the circuit branch between the circuit node corresponding to the circuit node 23 and the fifth terminal 61, which corresponds to the circuit branch 25 according to Fig. 2. In the second filter mode, the sixth capacitor 63 and the eighth capacitor 66 are connected in series in the circuit branch 76 between the fourth terminal 10 and the second central node 65, and the seventh capacitor 64 and the ninth capacitor 67 are connected in series in the circuit branch 77 between the fifth terminal 61 and the second central node 65.

[0100] The second central node 65 is a common node between the sixth terminal 62, the second terminal 63b of the sixth capacitor 63, and the first terminal 64a of the seventh capacitor 64. The second central node 65 is connected to the second terminal 62.

[0101] The first terminal 66a of the eighth capacitor 66 is connected to the fourth terminal 60 of the filter device 8. The second terminal 66b of the eighth capacitor 66 is connected to the first terminal 63a of the sixth capacitor 63. The second terminal 63b of the sixth capacitor 63 is connected to the first terminal 64a of the seventh capacitor 64 and the sixth terminal 62. The first terminal 64a of the seventh capacitor 64 is connected to the second terminal 63b of the sixth capacitor 63 and the sixth terminal 62. The second terminal 64b of the seventh capacitor 64 is connected to the first terminal 67a of the ninth capacitor 67. The second terminal 67b of the ninth capacitor 67 is connected to the fifth terminal 61.

[0102] In a third exemplary embodiment, all of the capacitors 13, 14, 16, 17, 28, 63, 64, 66, 67 and the switching devices 19, 69 may be located on a printed circuit board 50 along with the terminals 10, 11, 12, 60, 61, 62 (see FIG. 4). Alternatively, the sixth through ninth capacitors 63, 64, 66, 67, the second switching device 69 and the fourth through sixth terminals 60, 61, 62 may be located on a separate printed circuit board (not shown).

[0103] Furthermore, the second and third exemplary embodiments may be combined such that only some of the terminals 60, 61, 62 are designed as separate terminals, and some of the terminals are identical to the terminals 10, 11, 12. For example, the fourth terminal 60 may be identical to the first terminal 10, the fifth terminal 61 may be identical to the second terminal 11, and a sixth terminal 62 may be provided in addition to the third terminal 12. In addition to the first terminal 10 and the second terminal 12, the fourth terminal 60 and the fifth terminal 61 may also be provided, and the third terminal 12 and the sixth terminal 62 may also be identical.

[0104] FIG. 7 is a block diagram of one exemplary embodiment of an onboard electrical system 101 within a vehicle 100 .

[0105] The on-board electrical system 101 includes a traction battery 102 having a nominal voltage of, for example, 800 volts, a charging device 103 that can be connected to a power supply system 104 external to the vehicle to charge or discharge the traction battery 102, and a control device 105 configured to provide control information 20. The on-board electrical system 101 may be considered a high-voltage on-board electrical system because its operating voltage is generally greater than 60V.

[0106] The on-board electrical system 101 comprises a power converter 1 according to one of the above-mentioned exemplary embodiments, designed as an inverter. The power converter 1 is configured to supply power via a polyphase AC voltage to an electric machine 106 of the on-board electrical system 101 in order to drive the vehicle 100. The electric machine 106 is, for example, a permanently or electrically excited synchronous machine, an axial flux machine, or an asynchronous machine.

[0107] The on-board electrical system 101 comprises a further power converter 1 a according to the above-described exemplary embodiment, designed as an active rectifier or a DC / DC voltage converter and forming part of a charging device 103. The power converter 1 a is configured to convert a DC or AC voltage provided by a power supply system 104 external to the vehicle into a DC voltage for charging the traction battery 102.

[0108] The on-board electrical system 101 comprises a further power converter 1b according to the above-described exemplary embodiment, designed as a DC / DC voltage converter, which is configured to couple the on-board electrical system 101 to a further on-board electrical system 107 of the vehicle 100. The further on-board electrical system 107 is, for example, a low-voltage on-board electrical system having an operating voltage below 60 volts, such as 12 volts, 24 volts or 48 volts.

[0109] The control device 105 communicates with the charging device 103 via a signal line represented by a double-headed arrow. The control device 105 is configured to provide control information 20 to the power converters 1, 1a, 1b to adopt the second filter mode when and as long as the charging device 103 is connected to the vehicle's external power supply system 104. The second filter mode may therefore be considered, in particular, as a charging mode. In contrast, the control information 20 is provided, in particular, to adopt the first filter mode when the charging device 103 is disconnected from the vehicle's external power supply system 104 and when the vehicle 100 is moving. The first filter mode may therefore also be considered a driving mode.

[0110] The on-board electrical system 101 may further comprise an electrical conductor by which the third line 6 (see FIG. 1) of each power converter 1, 1a, 1b is conductively connected to the body 108 of the vehicle 101, so that the reference potential 7 can also be considered as the body potential, which is at the same time one of the potentials of the further on-board electrical system 107.

[0111] Thus, the vehicle 100 may be designed as a battery electric vehicle (BEV) or a hybrid vehicle.

Claims

1. a first line (2) for a first potential (3), a second line (4) for a second potential (5), a third line (6) for a reference potential (7), and a filter device (8), - a first terminal (10) connected to said first line (2), - a second terminal (11) connected to said second line (4), - a third terminal (12) connected to said third line (6), - a first capacitor (13) and a second capacitor (14) having a central node (15) formed therebetween with a conductive connection to said third terminal (12); a switching device (19) configured to switch between a first and a second filter mode of said filter device (8) based on control information (20); a filter device (8) having The filter device (8) comprises: a third capacitor (16) connected between the terminal (13a) of the first capacitor (13) opposite the central node (15) and the first terminal (10) of the filter device (8); a fourth capacitor (17) connected between the terminal (14b) of the second capacitor (14) opposite the central node (15) and the second terminal (11) of the filter device (8); The device further comprises: In the first filter mode, a first current path (21) for an interference current is formed on the first line (2) from the first terminal (10) of the filter device (8) via the third capacitor (16), the parallel connection of the first capacitor (13) and the second capacitor (14) and the central node (15) to the third terminal (12) of the filter device (8); and a second current path (22) for interference current is formed on the second line from the second terminal (11) of the filter device (8) via the fourth capacitor (17), the parallel connection of the first capacitor (13) and the second capacitor (14) and the central node (15) to the third terminal (12) of the filter device (8); A power converter (1, 1a, 1b) for an on-board electrical system (101) of an electrically drivable vehicle (100), wherein in the second filter mode, the admittance of the interference current along the first current path (21) and the second current path (22) is at least reduced compared to the first filter mode.

2. the filter device (8) is configured in the second filter mode to set a higher pole frequency and / or a lower effective total capacitance than in the first filter mode to filter the interference current between the first terminal (10) and the third terminal (12) and between the second terminal (11) and the third terminal (12).

10. The power converter of claim 1.

3. In the second filter mode, the admittance along the first current path (21) between the third capacitor (16) and the second capacitor (14) is at least reduced compared to the first filter mode, and the admittance along the second current path (22) between the fourth capacitor (17) and the first capacitor (13) is at least reduced compared to the first filter mode, or - the first current path (21) in the circuit branch between the third capacitor (16) and the second capacitor (14) and the second current path (22) in the circuit branch between the fourth capacitor (17) and the first capacitor (13) are interrupted; 3. The power converter according to claim 1 or 2.

4. The central node (15) - the third terminal (12) of the filter device (8); a terminal (13b) of the first capacitor (13) facing away from the third capacitor (16) and / or facing the second capacitor (14); a terminal (14a) of the second capacitor (14) facing away from the fourth capacitor (17) and / or facing the first capacitor (13); 4. The power converter of claim 1, wherein the common node of

5. The central node (15) is connected to the third terminal (12) of the filter device (8).

5. A power converter according to any one of claims 1 to 4.

6. the switching device (19) has a first terminal (19a), a second terminal (19b), and a switching path that can be controlled based on the control information (20); 6. A power converter according to any one of claims 1 to 5.

7. the first terminal (19a) of the switching device (19) has a common node with the first capacitor (13) and the third capacitor (16), and / or the second terminal (19b) of the switching device (19) has a common node with the second capacitor (14) and the fourth capacitor (17); 7. The power converter of claim 6.

8. the switching device (19) is configured to switch on the switching path to adopt the first filter mode and / or switch off the switching path to adopt the second filter mode.

8. The power converter according to claim 6 or 7.

9. The capacitance (C 1 , C 4 ) is the capacitance (C 2、 C 3 ), or larger, in particular at least twice as large, in particular at least five times as large; 9. A power converter according to any one of claims 1 to 8.

10. The capacitance (C 1 , C 4 ) are equal, and / or the capacitances (C 2 , C 3 ) are equal, 10. A power converter according to any one of claims 1 to 9.

11. The filter device (8) is connected in parallel with the first to fourth capacitors (13, 14, 16, 17) to the first terminal (10) and the second terminal (11) of the filter device (8), and in particular, the maximum capacitance (C 1 , C 2 , C 3 , C 4 ), in particular at least 5 times, preferably 10 times, larger than the capacity (C 5 a fifth capacitor (28) having a 11. A power converter according to any one of claims 1 to 10.

12. a fourth terminal (60) of the filter device (8) is the first terminal (10) of the filter device or is connected to the first line (2); a fifth terminal (61) of the filter device (8) is the second terminal (11) of the filter device (8) or is connected to the second line (4); a sixth terminal (62) of the filter device (8) is the third terminal (12) of the filter device or is connected to the third line (6); The filter device (8) a sixth capacitor (63) and a seventh capacitor (64) having a second central node (65) formed therebetween with a conductive connection to said sixth terminal (62); an eighth capacitor (66) connected between the terminal (63a) of the sixth capacitor (63) opposite the second central node (65) and the fourth terminal (60) of the filter device (8); a ninth capacitor (67) connected between the terminal (64b) of the seventh capacitor (64) opposite the second central node (65) and the fifth terminal (61) of the filter device (8); a second switching device (69) configured to switch between a first and a second filtering mode of said filtering device (8) in response to control information (20); and a third current path (71) for the interference current is formed on the first line (2) from the fourth terminal (60) of the filter device (8) through the eighth capacitor (66), the parallel connection of the sixth capacitor (63) and the seventh capacitor (64), and the second central node (65) to the sixth terminal (62) of the filter device (8); a fourth current path (72) for the interference current is formed on the second line from the fifth terminal (61) of the filter device (8) through the ninth capacitor (67), the parallel connection of the sixth capacitor (63) and the seventh capacitor (64), and the second central node (65) to the sixth terminal (62) of the filter device (8); In the second filter mode, the admittance of the interference current along the third current path (71) and the fourth current path (72) is at least reduced compared to the first filter mode.

12. A power converter according to any one of claims 1 to 11.

13. - the capacitance of the first capacitor (13) and the fourth capacitor (17) is greater than the capacitance of the second capacitor (14) and the third capacitor (16) (C 2 , C 3 ), the capacitance (C 6 , C 9 ) of the seventh capacitor (64) and the eighth capacitor (66) 7 , C 8 ), in particular at least twice as large, in particular at least five times as large, or - the capacitance of the first capacitor (13) and the fourth capacitor (17) is greater than the capacitance of the second capacitor (14) and the third capacitor (16) (C 2 , C 3 ), the capacitance (C 6 , C 9 ) of the seventh capacitor (64) and the eighth capacitor (66) 7 , C 8 ) smaller than, especially at most half, especially at most one-fifth, 13. A power converter according to claim 12 when dependent on claim 9.

14. The filter device (8) has a printed circuit board (50), the first to fourth capacitors (13, 14, 16, 17), in particular also the fifth capacitor (28) and / or the sixth to ninth capacitors (63, 64, 66, 67) are arranged on the printed circuit board (50); and / or - the first to third terminals (10, 11, 12) of the filter device (8) are arranged on the printed circuit board (50), and / or - the switching device (19) or the switching device (19, 69) is arranged on the printed circuit board (50), and / or The power converter (1) is connected between the first line (2) and the second line (4), and in particular, the maximum capacitance (C 1 , C 2 , C 3 , C 4 a DC link capacitor (40) having a capacitance at least 100 times, preferably 500 times, greater than the capacitance of the first line (2) and the second line (4), and a converter circuit (41) connected between the first line (2) and the second line (4), the filter device (8) being arranged on the opposite side of the DC link capacitor (40) from the converter circuit (41), 14. A power converter according to any one of claims 1 to 13.

15. An on-board electrical system (101) for an electrically drivable vehicle (100), comprising: at least one power converter (1, 1a, 1b) according to any one of claims 1 to 14; a traction battery (102); a charging device (103) connectable to a power supply system (104) external to the vehicle for charging or discharging the traction battery (102); and a control device (105) configured to provide the control information (20) for adopting the second filter mode when and / or as long as the charging device (103) is connected to the power supply system (104) external to the vehicle. An on-board electrical system (101).

Images