Adaptive Filter with Y-Capacitor for Three-Phase DC Vehicle Electrical Systems

Abstract

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); a first terminal (10) connected to a first line (2); a second terminal (11) connected to the second line (4); a third terminal (12) connected to the third line (6); a first capacitor (13) through which a first current path (14) is routed from the first terminal (10) to the third terminal (12); a second capacitor (15) through which a second current path (16) is routed from the second terminal (11) to the third terminal (12); a third capacitor (17) forming a conductive connection between a central node (18) between the first capacitor (13) and the second capacitor (15) and the third terminal (12); and a switching device (19) configured to switch, based on control information (20), between a first filter mode in which the first current path (14) and the second current path (16) are routed to the third terminal (12) past the third capacitor (17) and a second filter mode in which the first current path (14) and the second current path (16) are routed to the third terminal (12) via the third capacitor (17); and a filter device (8) having the filter device (8).

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, 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 through which a first current path is routed from the first terminal to the third terminal, a second capacitor through which a second current path is routed from the second terminal to the third terminal, and a filter device having a switching device configured to switch 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 controlled 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 first potential line and a second potential line, 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 a further interference suppression capacitor 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 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, the magnitude of which 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 that ensures electrical safety. In combination with the possible additional filter inductance, this results 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] This object is achieved according to the invention by the fact that in a power converter of the type mentioned at the beginning, the filter device further comprises a third capacitor forming a conductive connection between a central node between the first capacitor and the second capacitor and a third terminal, the first current path and the second current path being routed past the third capacitor to the third terminal in the first filter mode and routed via the third capacitor to the third terminal in the second 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, and a third capacitor. A first current path is routed from the first terminal to the third terminal via the first capacitor. A second current path is routed from the second terminal to the third terminal via the second capacitor. The third capacitor forms a conductive connection between a central node and the third terminal. The central node is located between the first capacitor and the second capacitor. The filter device further includes a switching device. The switching device is configured to switch between a first filter mode and a second filter mode based on the control information, wherein in the first filter mode, the first current path and the second current path are routed past the third capacitor to the third terminal, and in the second filter mode, the first current path and the second current path are routed through the third capacitor to the third terminal.

[0012] In the power converter according to the present invention, the first and second current paths are routed through the third capacitor in the first filter mode so that the capacitances of the first and second capacitors essentially function as Y capacitances. This allows for particularly efficient suppression of common-mode interference on the first and second lines. In the second filter mode, the first and second current paths are routed through the third capacitor. The third capacitor therefore advantageously provides a well-defined capacitance between the central node and the third terminal, allowing for accurate determination of the energy budget when designing the power converter. At the same time, the effective Y capacitance of the filter device can be reduced in the second filter mode compared to the first filter mode.

[0013] With regard to electrical safety, the time progression of the body current in the event of an insulation fault can also be more accurately limited with additional advantages, since by specifying the capacitance of the third capacitor the equivalent capacitance in the second filter mode, and therefore the discharge time constant resulting from the equivalent capacitance and the body resistance, can be brought into a range with low fibrillation risk or outside of this range. Another advantage of the power converter according to the invention is that due to the presence of the third capacitor in the second filter mode, the capacitances of the first and second capacitors additionally act partly as X-capacitances and thus allow stronger suppression of normal mode interference.

[0014] The power converter according to the present invention may be embodied as an inverter, a DC / DC voltage converter, or an active rectifier. The power converter according to the present invention may further include 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 regard, the reference potential may be considered as a housing potential.

[0015] 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, where a connection device is formed, in particular for electrically connecting the power converter to a DC voltage source. The filter device is preferably arranged on the DC voltage terminal side.

[0016] 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.

[0017] The first capacitor, the second capacitor, and the third capacitor may each have a first terminal and a second terminal between which the capacitance of the capacitor is provided. The first terminal of the first capacitor may be connected to the first terminal of the filter device. The second terminal of the second capacitor may be connected to the second terminal of the filter device.

[0018] The first, second and third 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.

[0019] Preferably, in the first filter mode, the conductive connection from the central node to the third terminal passes completely through the third capacitor. However, in the first filter mode, it is also possible for an additional current path to be routed along the third capacitor. The additional current path preferably has a higher impedance than the portions of the first and second current paths that pass through the third capacitor.

[0020] Preferably, the filter device of the power converter according to the invention is configured to set a higher pole frequency in the second filter mode than in the first filter mode in order to filter the common-mode current on the first line and the second line along the first current path and the second current path, respectively, so that in the event of a first insulation fault, the discharge time constant resulting from the effective Y capacitance and the body resistance can be advantageously changed thereby.

[0021] In one preferred configuration of the power converter according to the present invention, the central node is a common node of a terminal of the third capacitor opposite the third terminal, a terminal of the first capacitor opposite the first terminal and / or facing the second capacitor, and a terminal of the second capacitor opposite the second terminal and / or facing the first capacitor. The terminal of the third capacitor opposite the third terminal may correspond to the second terminal of the third capacitor. The terminal of the first capacitor opposite the first terminal of the filter device and / or facing the second capacitor may correspond to the second terminal of the first capacitor. The terminal of the second capacitor opposite the second terminal of the filter device and / or facing the first capacitor may correspond to the first terminal of the second capacitor.

[0022] Preferably, the terminal of the third capacitor opposite to the central node is connected to the third terminal, and the terminal of the third capacitor opposite to the central node may correspond to the first terminal of the third capacitor.

[0023] Regarding the switching device of the power converter according to the present invention, it is preferred if the switching device has a first terminal, a second terminal and a switching path that can be controlled based on the control information.

[0024] The first terminal of the switching device may be connected to the central node and / or to the third capacitor, in particular to the second terminal thereof. Preferably, the first terminal of the switching device, the central node and the second terminal of the third capacitor form a common circuit node. The second terminal of the switching device may be connected to the third terminal of the filter device and / or to the third capacitor, in particular to the first terminal thereof. Preferably, the second terminal of the switching device, the third terminal of the filter device and the first terminal of the third capacitor form a common circuit node.

[0025] In a preferred development, the switching device is also 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.

[0026] Generally, in the power converter according to the invention, it is advantageous if the switching device is connected in parallel with the third capacitor, in which case the first current path and the second current path can be routed through the switching device past the third capacitor in the first filter mode.

[0027] In order to filter common-mode currents particularly efficiently in the first filter mode, the switching device may be designed as a bidirectional conducting and / or blocking switch.

[0028] Regarding the dimensions of the capacitors, the following may be provided: the capacitance of the third capacitor may be smaller than the capacitance of the first capacitor; the capacitance of the third capacitor may be smaller than the capacitance of the second capacitor.

[0029] The capacitance of the first capacitor and the second capacitor may be the same, which allows for a particularly symmetrical voltage distribution across the first and second capacitors.

[0030] To also enable efficient suppression of normal mode interference in the first filter mode, the filter device may further comprise a fourth capacitor connected in parallel with the first capacitor and the second capacitor to the first terminal of the filter device and the second terminal of the filter device, in other words, the fourth capacitor may provide a fixed X capacitance.

[0031] In one preferred configuration of the power converter according to the present invention, the filter device has a printed circuit board. The first, second, and third capacitors may be disposed on the printed circuit board. The fourth capacitor may also be disposed on the printed circuit board. The first, second, and third terminals of the filter device may be disposed on the printed circuit board. The switching device may be disposed on the printed circuit board.

[0032] The power converter according to the present invention may further comprise a DC link capacitor connected between the first line and the second line.

[0033] The power converter according to the invention may further comprise a converter circuit connected between the first line and the second line. 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 line and the second line in switching mode. The filter device is preferably arranged on the side of the DC link capacitor opposite the converter circuit.

[0034] 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, which may be formed around the lines by ferrite cores, e.g. nanocrystalline cores, iron powder cores or other cores made from magnetic material.

[0035] 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.

[0036] The object on which the present 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.

[0037] It is therefore advantageously possible to predefine a first filter mode in the operating mode and a second filter mode in the charging mode of the vehicle or on-board electrical system.

[0038] The traction battery preferably has a nominal voltage of at least 400 volts, preferably at least 600 volts, particularly preferably at least 800 volts.

[0039] The power converter of the on-board electrical system may be designed as an inverter configured to electrically supply a polyphase AC voltage to an electric machine, in particular a permanently or electrically excited synchronous machine, an axial flux motor, or an asynchronous machine, in order to drive the vehicle.

[0040] 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.

[0041] 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.

[0042] The on-board electrical system may further include an electrical wire, such as a conductive fastener or ground strip, by which the third line of the at least one power converter is conductively connected to the body of the vehicle.

[0043] 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]

[0044] [Figure 1] 1 is a circuit diagram of an exemplary embodiment of a power converter according to the present invention; [Figure 2] 1 is a schematic diagram of a power converter in accordance with an exemplary embodiment; [Figure 3] 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

[0045] FIG. 1 is a circuit diagram of an exemplary embodiment of a power converter 1 .

[0046] 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.

[0047] 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.

[0048] 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 through which a first current path 14 is routed from the first terminal 10 to the third terminal 12, and a second capacitor 15 through which a second current path 16 is routed from the second terminal 11 to the third terminal 12. The current paths 14, 16 are shown purely diagrammatically by dashed lines in Figure 1. The filter device further has a third capacitor 17 forming a conductive connection between the third terminal 12 and a central node 18 located between the first capacitor 13 and the second capacitor 15.

[0049] 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, the first current path 14 and the second current path 16 are routed past the third capacitor 17 to the third terminal 12. In the second filter mode, the first current path 14 and the second current path 16 are routed through the third capacitor 17 to the third terminal 12.

[0050] In the first filter mode, the capacitances C1, C2 of the first capacitor 13 and the second capacitor 15 can act as a Y capacitance for filtering common-mode interference on the first and second lines 2, 4. In the second filter mode, the capacitances C1, C2 together with the capacitance C3 of the third capacitor 17 form a capacitor network, which in particular provides a clear capacitance between the central node 18 and the third terminal 12 and further provides an X capacitance for filtering normal-mode interference on the first line 2 and the second line 4. In the second filter mode, the filter device 8 is configured to set a higher pole frequency than in the first filter mode for filtering common-mode currents on the first line 2 and the second line 4 along the first current path 14 and the second current path 16, respectively.

[0051] The first capacitor 13 has a first terminal 13a and a second terminal 13b. The second capacitor 15 has a first terminal 15a and a second terminal 15b. The third capacitor has a first terminal 17a and a second terminal 17b. The switching device has a first terminal 19a and a second terminal 19b between which a switching path that can be controlled based on control information 20 is formed.

[0052] In this exemplary embodiment, the filter device 8 is implemented in terms of a circuit, particularly by the fact that the switching device 19 is connected in parallel with the third capacitor 17 and is configured to switch on the switching path to adopt a first filter mode and to switch off the switching path to adopt a second filter mode. In particular, a first terminal 19a of the switching device 19 is connected to a second terminal 17b of the third capacitor 17, and a second terminal 19b of the switching device 19 is connected to the first terminal 17a of the third capacitor 17.

[0053] Furthermore, a first terminal 17a of the third capacitor 17 opposite the central node 18 is connected to the third terminal 12 of the filter device 8. A second terminal 17b of the third capacitor 17 is connected to the central node 18. In particular, the third terminal 12 of the filter device 8, the first terminal 17a of the third capacitor 17, and the second terminal 19b of the switching device 19 form a common circuit node of the filter device 8. Therefore, the central node 18, the second terminal 17b of the third capacitor 17, and the first terminal 19a of the switching device 19 form a common circuit node of the filter device 8.

[0054] In this exemplary embodiment, the first terminal 13a of the first capacitor 13 is connected to the first terminal 10 of the filter device 8. The second terminal 15b of the second capacitor 15 is connected to the second terminal 11 of the filter device 8. The central node 18 further forms a common node between the second terminal 13b of the first capacitor 13, the first terminal 15a of the second capacitor 15, and the second terminal 17b of the third capacitor 17.

[0055] In this exemplary embodiment, when the switching device 19 adopts the second filter mode by opening the switching path, the result is the following equivalent capacitance C for filtering common-mode interference: eq Is:

number

number

number

[0056] In this exemplary embodiment, a fourth capacitor 21 having a first terminal 21a and a second terminal 21b of the filter device 8 may be optionally provided. The fourth capacitor 21 is connected in parallel with the first capacitor 13 and the second capacitor 15 to the first terminal 10 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 13a of the first capacitor 13, and the first terminal 21a of the fourth capacitor 21 form a common circuit node. Also, the second terminal 11 of the filter device 8, the second terminal 15b of the second capacitor 15, and the second terminal 21b of the fourth capacitor 21 form a common circuit node. The fourth capacitor 21 provides a fixed X capacitance.

[0057] 1 further shows a DC link capacitor 40 connected between 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. 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.

[0058] 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, for example by ferrite cores. The filter elements 42 to 45 are arranged close 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.

[0059] FIG. 1 shows the parasitic inductances L along the first line 2 and the 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 may be selected to be smaller than

[0060] FIG. 2 is a schematic diagram of a power converter 1 according to an example embodiment.

[0061] The filter device 8 comprises a printed circuit board 50 on which terminals 10, 11, 12, capacitors 13, 15, 17, 21 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 the 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 may be located closer to the converter circuit 41 than the filter device 8, relative to the length of the busbar 51.

[0062] 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 a 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 contained in the housing 55.

[0063] 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.

[0064] FIG. 3 is a block diagram of one exemplary embodiment of an onboard electrical system 101 within a vehicle 100 .

[0065] 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.

[0066] The on-board electrical system 101 comprises a power converter 1 according to the above-described exemplary embodiment, 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.

[0067] 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.

[0068] 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.

[0069] 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 to adopt the first filter mode, in particular, 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.

[0070] 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.

[0071] 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), and a third line (6) for a reference potential (7); - 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) through which a first current path (14) is routed from said first terminal (10) to said third terminal (12); a second capacitor (15) through which a second current path (16) is routed from the second terminal (11) to the third terminal (12); and a switching device (19) configured to switch between a first filter mode and a second filter mode based on control information (20); and a filter device (8) having The filter device (8) further comprises a third capacitor (17) forming a conductive connection between a central node (18) between the first capacitor (13) and the second capacitor (15) and the third terminal (12), and the first current path (14) and the second current path (16) are routed past the third capacitor (17) to the third terminal (12) in the first filter mode, and are routed through the third capacitor (17) to the third terminal (12) in the second filter mode. A power converter (1, 1a, 1b) for an on-board electrical system (101) of an electrically drivable vehicle (100), comprising:

2. the filter device (8) is configured to set a pole frequency higher in the second filter mode than in the first filter mode in order to filter common mode currents on the first line (2) and the second line (4) along the first current path (14) and the second current path (16), respectively.

10. The power converter of claim 1.

3. The central node (18) - a terminal (17b) of the third capacitor (17) opposite to the third terminal (12); a terminal (13b) of the first capacitor (13) facing away from the first terminal (10) and / or facing the second capacitor (15); a terminal (15a) of the second capacitor (15) facing away from the second terminal (11) and / or facing the first capacitor (13); 3. The power converter according to claim 1, wherein the common node is a common node of the first and second inputs.

4. A terminal (17a) of the third capacitor (17) opposite to the central node (18) is connected to the third terminal (12).

4. A power converter according to any one of claims 1 to 3.

5. 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).

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

6. the first terminal (19a) of the switching device (19) is connected to the central node (18) and / or the third capacitor (17); 6. The power converter of claim 5.

7. the second terminal (19b) of the switching device (19) is connected to the third terminal (12) of the filter device (8) and / or the third capacitor (17); 7. The power converter according to claim 5 or 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. A power converter according to any one of claims 5 to 7.

9. The switching device (19) is connected in parallel with the third capacitor (17).

9. A power converter according to any one of claims 1 to 8.

10. the switching device (19) is designed as a bidirectional conductive and / or disconnecting switch, 10. A power converter according to any one of claims 1 to 9.

11. - the capacitance (C 3 ) of the first capacitor (13) and / or the second capacitor (15) 1 , C 2 ) and / or - the capacitance (C 1 , C 2 ) are the same, 11. A power converter according to any one of claims 1 to 10.

12. the filter device (8) further comprises a fourth capacitor (21) connected in parallel with the first capacitor (13) and the second capacitor (15) to the first terminal (10) of the filter device (8) and the second terminal (11) of the filter device (8); 12. A power converter according to any one of claims 1 to 11.

13. The filter device (8) has a printed circuit board (50), the first to third capacitors (13, 15, 17), and in particular the fourth capacitor (21), are also 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 - said switching device (19) is arranged on said printed circuit board (50); 13. A power converter according to any one of claims 1 to 12.

14. a DC link capacitor (40) connected between 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 a side of the DC link capacitor (40) opposite to the converter circuit (41); 14. The power converter of claim 1, further comprising:

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).

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