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

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); - first to third terminals (10-12) connected to first to third lines (2, 4, 6); a first capacitor (13) connected to a first current path (14) from the first terminal (10) to the third terminal (12) and affecting a first impedance along the first current path (14) to dissipate common mode currents associated with the first and second lines (2, 4) towards the third terminal (12); a second capacitor (15) connected to a second current path (16) from the second terminal (11) to the third terminal (12) and affecting a second impedance along the second current path (16) to dissipate the common mode current towards the third terminal (12); at least one resistor circuit (17, 18, 27) having first and second resistor components (19, 20), and a switching device (21) configured to switch between a first filter mode in which each of the first and second impedances is provided with a predefined absolute value and a second filter mode in which each of the first and second impedances is provided with a predefined absolute value that is increased compared to the first filter mode, by changing the interconnections of resistor components (19, 20) in the filter device (8) based on control information (22); and a filter device (8) having the same.

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 comprising: a first line for a first potential; a second line for a second potential; a third line for a reference potential; 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 connected to a first current path from the first terminal to the third terminal and affecting a first impedance along the first current path to dissipate a common mode current associated with the first and second lines toward the third terminal; a second capacitor connected to a second current path from the second terminal to the third terminal and affecting a second impedance along the second current path to dissipate the common mode current toward the third terminal; and the 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 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 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. [Prior art documents] [Patent documents]

[0007] [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]

[0008] 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]

[0009] This object is achieved according to the invention in the case of a power converter of the type mentioned at the beginning in that the filter device has at least one resistor circuit having a first resistor component and having a second resistor component, and the switching device is further configured to provide, in a first filter mode, each of the first impedance and the second impedance with a predefined absolute value, and to provide, in a second filter mode, each of the first impedance and the second impedance with an increased predefined absolute value compared to the first filter mode, by changing the interconnection of the resistor components in the filter device.

[0010] A power converter according to the present invention for use in an on-board electrical system of an electrically drivable vehicle 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 and a second capacitor. The first capacitor is connected to a first current path from the first terminal to a third terminal. The first capacitor affects a first impedance along the first current path to dissipate a common-mode current toward the third terminal. The common-mode current is associated with the first line and the second line. The second capacitor is connected to a second current path from the second terminal to the third terminal. The second capacitor affects a second impedance along the second current path to dissipate the common-mode current toward the third terminal. The filter device further includes at least one resistor circuit. The at least one resistor circuit includes a first resistor component and a second resistor component. 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 control information. The switching device is further configured to provide each of the first impedance and the second impedance with a predetermined absolute value in the first filter mode by changing the interconnections of the resistor components in the filter device. The switching device is further configured to provide each of the first impedance and the second impedance with an increased predetermined absolute value in the second filter mode compared to the first filter mode by changing the interconnections.

[0011] The power converter according to the invention provides for different predefined impedances along the current paths in the first and second filter modes. This advantageously limits the time profile of the body current in the event of an insulation fault more precisely, since the different impedances mean that the time at which the energy stored in the first and second capacitors is discharged towards the third terminal can be varied. As a result, the discharge time constants, particularly those due to the body resistance and the respective impedances, can be kept within a range where there is no or low risk of fibrillation. A further advantage of the power converter according to the invention is that the capacitances of the first and second capacitors can also act as Y-capacitances in the second filter mode, thus enabling at least partial suppression of common-mode interference in the second filter mode.

[0012] 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 be considered as the housing potential.

[0013] 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 embodiment, 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, at which connection devices are 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.

[0014] 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.

[0015] A portion of the common mode current flowing along the first line may be dissipated through a first impedance, particularly via a first current path, and a portion of the common mode current flowing along the second line may be dissipated through a second impedance, particularly via a second current path.

[0016] The first and second 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 first capacitor may be connected to a first terminal of the filter device. The first terminal of the second capacitor may be connected to a second terminal of the filter device. The first and second capacitors may each be formed by a single capacitor component or a plurality of interconnected capacitor components.

[0017] A resistor circuit may be provided having a first resistor component and a second resistor component. Also, a plurality of resistor circuits may be provided each having a first resistor component and a second resistor component. The or each resistor circuit may have a first terminal and a second terminal. The first resistor component and the second resistor component may each have a first terminal and a second terminal between which the ohmic resistance of the resistor component is provided.

[0018] 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] In one preferred embodiment, the filter device of the power converter according to the invention is configured in the second filter mode to filter the common-mode current along the first current path and along the second current path by setting the time constant of the low-pass filter formed by the capacitor and at least one resistor circuit higher in each case than in the first filter mode, so that in the second filter mode the risk of fibrillation can be targetedly kept within a range that meets the relevant criteria.

[0020] Typically, the filter device of the power converter according to the invention has a central node located between the first capacitor and the second capacitor.

[0021] Preferably, at least one resistor circuit is connected to the terminal of the first capacitor or the second capacitor facing the central node. In particular, at least one resistor circuit is connected to the second terminal of the first capacitor or the second terminal of the second capacitor. The terminal of the first capacitor facing the central node may be its second terminal. The terminal of the second capacitor facing the central node may be its second terminal.

[0022] Regarding the interconnection of the at least one resistor circuit in the filter device, the following preferred embodiments are suitable: A resistor circuit may be provided connected to the circuit branch between the central node and the third terminal, and preferably has a first terminal connected to the third terminal and a second terminal connected to the central node.

[0023] Alternatively or additionally, a resistor circuit may be provided connected in series with the first capacitor in the circuit branch between the first terminal and the central node, the first terminal of the resistor circuit being particularly connected to the second terminal of the first capacitor, and the second terminal of the resistor circuit being particularly connected to the central node.

[0024] Alternatively or additionally, a resistor circuit may be connected in series with the second capacitor in the circuit branch between the second terminal and the central node, with a first terminal of the resistor circuit being particularly connected to the second terminal of the second capacitor, and with the second terminal of the resistor circuit being particularly connected to the central node.

[0025] Thus, the at least one resistor circuit may comprise one resistor circuit, two resistor circuits interconnected as described above, or three resistor circuits. The resistor circuits may also be designed differently.

[0026] In one preferred embodiment, in a power converter according to the present invention, a switching device may be provided having a switch for the or each resistor circuit, the switch having a first terminal, a second terminal and a switching path operable based on control information between the first terminal of the switch and the second terminal of the switch.

[0027] According to a variant of the first preferred embodiment, the switch forms a series circuit with the first resistor component and the second resistor component is connected in parallel with the series circuit, and depending on the switching state of the switch, the total resistance of the resistor circuit may therefore correspond either to the resistance of the second resistor component or to the reciprocal of the sum of the reciprocals of the resistances of the first and second resistor components.

[0028] In this case, the first terminal of the resistor circuit, the first terminal of the switch, and the first terminal of the second resistor component may be arranged to form a common circuit node, the second terminal of the switch may be connected to the first terminal of the first resistor component, and the second terminal of the first resistor component, the second terminal of the second resistor component, and the second terminal of the resistor circuit may form the common circuit node.

[0029] According to a variant of the second preferred embodiment, the switch forms a parallel circuit with the second resistor component, and the first resistor component is connected in series with the parallel circuit, so that, depending on the switching state of the switch, the total resistance of the resistor circuit may correspond either to the resistance of the first resistor component or to the sum of the resistances of the first and second resistor components.

[0030] In this case, the first terminal of the first resistor component, the first terminal of the switch, and the first terminal of the resistor circuit may form a common circuit node, the second terminal of the first resistor component, the second terminal of the switch, and the first terminal of the second resistor component may form a common circuit node, and the second terminal of the second resistor component may be connected to the second terminal of the resistor circuit.

[0031] Regardless of the variants of the two embodiments described above, the switching device may be configured to switch on to adopt the first filter mode and / or switch off to adopt the second filter mode.

[0032] In the power converter according to the invention, it is further preferred that the resistance value of the first resistor component is smaller than the resistance value of the second resistor component. Thus, particularly in combination with the circuit-oriented design described above, it is possible to predefine a lower total resistance of the resistor circuit in the first filter mode than in the second filter mode.

[0033] 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.

[0034] The capacitance of the first and second capacitors may be the same, which allows for a particularly symmetrical voltage distribution across the first and second capacitors.

[0035] To also enable efficient suppression of push-pull disturbances, the filter device may further comprise a third capacitor connected in parallel with the first and second capacitors to the first terminal of the filter device and the second terminal of the filter device, in other words, the third capacitor may provide a fixed X capacitance.

[0036] In one preferred embodiment of the power converter according to the present invention, the filter device has a printed circuit board. The first capacitor, the second capacitor, and the at least one resistor circuit may be disposed on the printed circuit board. The third capacitor may also be disposed on the printed circuit board. The first to 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.

[0037] The power converter according to the invention may further comprise a DC link capacitor connected between the first line and the second line.

[0038] 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.

[0039] 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, such as nanocrystalline cores, iron powder cores or other cores made of magnetic material.

[0040] 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 circuit capacitor side and the DC link capacitor.

[0041] 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.

[0042] It is therefore advantageously possible to predefine a first filter mode in an operating mode of the vehicle or on-board electrical system and a second filter mode in a charging mode.

[0043] The traction battery preferably has a nominal voltage of at least 400 volts, preferably at least 600 volts, particularly preferably at least 800 volts.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Further advantages and details of the invention will emerge from the exemplary embodiments described below with reference to the drawings, in which: The drawings are schematic diagrams. [Brief explanation of the drawings]

[0049] [Figure 1] 1 is a circuit diagram of a first 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] 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 4] 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 5] 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

[0050] FIG. 1 is a circuit diagram of an exemplary embodiment of a power converter 1 .

[0051] 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.

[0052] 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.

[0053] 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 8 further has a first capacitor 13 connected to a first current path 14 from the first terminal 10 to the third terminal 12 and affecting a first impedance along the first current path 14 to dissipate common-mode currents toward the third terminal 12, where the common-mode currents are associated with the first and second lines 2, 4. The filter device 8 further has a second capacitor 15 connected to a second current path 16 from the second terminal 11 to the third terminal 12 and affecting a second impedance along the second current path 16 to dissipate common-mode currents associated with the first and second lines 2, 4 toward the third terminal 12. In particular, a portion of the common-mode current flowing on the first line 2 can thus be dissipated from the first terminal 10 to the third terminal 12 via the first current path 14. Thus, part of the common mode current flowing in the second line 4 can be dissipated from the second terminal 11 to the third terminal 12 via the second current path 16. The current paths 14, 16 are shown purely diagrammatically by dashed lines in Figure 1. The capacitors 13, 15 have first terminals 13a, 15a and second terminals 13b, 15b, respectively.

[0054] Additionally, filter device 8 includes a first resistor circuit 17 and a second resistor circuit 18. Resistor circuits 17, 18 each include a first resistor component 19 and a second resistor component 20. Resistor circuits 17, 18 each include a first terminal 17a, 18a and a second terminal 17b, 18b, respectively. Resistor components 19, 20 each include a first terminal 19a, 20a and a second terminal 19b, 20b, respectively.

[0055] Furthermore, the filter device 8 comprises a switching device 21. The switching device 21 is configured to switch between a first filter mode and a second filter mode based on control information 22. For this purpose, the switching device 21 changes the interconnections of resistor components 19, 20 in the filter device so that in the first filter mode, the first impedance and the second impedance are each given a predefined absolute value, and in the second filter mode, the first impedance and the second impedance are each given a predefined absolute value that is increased compared to the first filter mode. Thus, in the second filter mode, the filter device 8 is configured to set the time constant of the low-pass filter formed by the capacitors 13, 15 and the resistor circuits 17, 18 higher than in the first filter mode in order to filter the common-mode current along the first current path 14 and the second current path 16, respectively.

[0056] The filter device 8 has a central node 23 between the first capacitor 13 and the second capacitor. A first resistor circuit 17 is connected in series with the first capacitor 13 between the first terminal 10 and the central node 23. A second resistor circuit 18 is connected in series with the second capacitor 15 between the second terminal 11 and the central node 23. In this case, the first resistor circuit 17 is connected to the second terminal 13b of the first capacitor 13 facing the central node 23. The second resistor circuit 18 is connected to the second terminal 15b of the second capacitor 15 facing the central node.

[0057] In this exemplary embodiment, central node 23 is directly connected to third terminal 12 of filter device 8. A first current path 14 is routed from first terminal 10 to third terminal 12 via first capacitor 13, first resistor circuit 17, and central node 23. A second current path is routed from second terminal 11 to third terminal 12 via second capacitor 15, second resistor circuit 18, and central node.

[0058] In particular, in the first exemplary embodiment, a first terminal 13a of the first capacitor 13 is further provided to be connected to the first terminal 10 of the filter device 8. A first terminal 15a of the second capacitor 15 is connected to the second terminal 11 of the filter device 8. A first terminal 17a of the first resistor circuit 17 is connected to the second terminal 13b of the first capacitor 13. A second terminal 17b of the first resistor circuit 17 is connected to the central node 23. A first terminal 18a of the second resistor circuit 18 is connected to the second terminal 15b of the second capacitor 15. A second terminal 18b of the second resistor circuit 18 is connected to the central node 23.

[0059] Furthermore, the switching device 21 has a first switch 24 for the first resistor circuit 17 and a second switch 25 for the second resistor circuit 18. The switches 24, 25 each have a first terminal 24a, 25a and a second terminal 24b, 25b with a switching path formed therebetween that is operable based on the control information 22. The switching device 21 is configured to switch the respective switches 24, 25 on to employ the first filter mode, and to switch the respective switches 24, 25 off to employ the second filter mode.

[0060] In this exemplary embodiment, each switch 24, 25 forms a series circuit with a first resistor component 19. A second resistor component 20 is in each case connected in parallel with the series circuit consisting of the switch 24, 25 and the first resistor component 19.

[0061] Specifically, in the first resistor circuit 17, the first terminal 24a of the first switch 24, the first terminal 20a of the second resistor component 20, and the first terminal 17a of the first resistor circuit 17 form a common circuit node. The second terminal 24b of the first switch 24 is connected to the first terminal 19a of the first resistor component 19. The second terminal 19b of the first resistor component 19, the second terminal 20b of the second resistor component 20, and the second terminal 17b of the first resistor circuit 17 form a common circuit node.

[0062] Thus, in the second resistor circuit 18, the first terminal 25a of the second switch 25, the first terminal 20a of the second resistor component 20, and the first terminal 18a of the second resistor circuit 18 form a common circuit node. The second terminal 25b of the second switch 25 is connected to the first terminal 19a of the first resistor component 19. The second terminal 19b of the first resistor component 19, the second terminal 20b of the second resistor component 20, and the second terminal 18b of the second resistor circuit 18 form a common circuit node.

[0063] Optionally, a third capacitor 26 is provided having a first terminal 26a and a second terminal 26b of the filter device 8. The third capacitor 26 is connected in parallel with the first capacitor 13 and the second capacitor 15, and in this exemplary embodiment also in parallel with the resistor networks 17, 18, 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 26a of the third capacitor 26 form a common circuit node. Furthermore, the second terminal 11 of the filter device 8, the first terminal 15b of the second capacitor 15, and the second terminal 26b of the third capacitor 26 form a common circuit node. The third capacitor 26 provides a fixed X capacitance.

[0064] The dimensions of the components of the filter device 8 are such that the capacitance C1 of the first capacitor 13 is equal to the capacitance C2 of the second capacitor 15. The capacitance C3 of the third capacitor 26 is typically greater than the capacitances C1 and C2. The resistance R1 of each first resistor component 19 is less than the resistance R2 of each second resistor component 20.

[0065] 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.

[0066] 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.

[0067] 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 may be selected to be smaller than

[0068] FIG. 2 is a schematic diagram of a power converter 1 according to an exemplary embodiment.

[0069] The filter device 8 comprises a printed circuit board 50 on which terminals 10, 11, 12, capacitors 13, 15, 26, resistor circuits 18, 19 and switching device 21 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.

[0070] 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 accommodated in the housing 55.

[0071] 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.

[0072] In the following, further exemplary embodiments of the power converter 1 are described to which details relating to the first exemplary embodiment may be transferred unless the description indicates otherwise. In this specification, identical or functionally identical components are designated by the same reference numerals.

[0073] FIG. 3 is a circuit diagram of a filter device 8 according to a second exemplary embodiment of the power converter 1.

[0074] In the second exemplary embodiment, the switches 24, 25 form a parallel circuit with the respective second resistor component 20. The respective first resistor component 19 is connected in series with this parallel circuit.

[0075] Specifically, in the first resistor circuit 17, the first terminal 24a of the first switch 24, the first terminal 20a of the second resistor component 20, and the first terminal 17a of the first resistor circuit 17 form a common circuit node. The second terminal 24b of the first switch 24, the second terminal 20b of the second resistor component 20, and the first terminal 19a of the first resistor component 19 form a common circuit node. The second terminal 19b of the first resistor component 19 is connected to the second terminal 17b of the first resistor circuit 17.

[0076] Thus, in the second resistor circuit 18, the first terminal 25a of the second switch 25, the first terminal 20a of the second resistor component 20, and the first terminal 18a of the second resistor circuit 18 form a common circuit node. The second terminal 25b of the second switch 25, the second terminal 20b of the second resistor component 20, and the first terminal 19a of the first resistor component 19 form a common circuit node. The second terminal 19b of the first resistor component 19 is connected to the second terminal 18b of the second resistor circuit 18.

[0077] It is again pointed out that, as in the first exemplary embodiment, the resistance value R1 of each first resistor component 19 is smaller than the resistance value R2 of each second resistor component 20, and that the switching device 21 is configured to switch on each switch 24, 25 to adopt the first filter mode and to switch off each switch 24, 25 to adopt the second filter mode.

[0078] FIG. 4 is a circuit diagram of a filter device 8 according to a third exemplary embodiment of the power converter 1.

[0079] In the third exemplary embodiment, there is only one resistor circuit 27 and one switch 28 of the switching device 21. The resistor circuit 27 is connected to a circuit branch between the central node 23 and the third terminal 12 of the filter device 8. In particular, a first terminal 27a of the resistor circuit 27 is connected to the third terminal 12, and a second terminal 27b of the resistor circuit 27 is connected to the central node 23. In particular, a first current path 14 is routed from the first terminal 10 to the third terminal 12 via the first capacitor 13, the central node 23, and the resistor circuit 27, and a second current path 16 is routed from the second terminal 11 to the third terminal 12 via the central node 23 and the resistor circuit 27.

[0080] The resistor circuit 27 is designed similarly to the resistor circuits 17, 18 according to the first exemplary embodiment. In other words, in this third exemplary embodiment, the switch 28 forms a series circuit with the first resistor component 19, and the second resistor component 20 is connected in parallel with the series circuit consisting of the switch 28 and the first resistor component 19.

[0081] Specifically, in resistor circuit 27, first terminal 28a of switch 28, first terminal 20a of second resistor component 20, and first terminal 27a of resistor circuit 27 form a common circuit node. Second terminal 28b of switch 28 is connected to first terminal 19a of first resistor component 19. Second terminal 19b of first resistor component 19, second terminal 20b of second resistor component 20, and second terminal 27b of resistor circuit 27 form a common circuit node.

[0082] In the third exemplary embodiment, the second terminals 13b, 15b of the capacitors 13, 15 are connected to the central node 23 or form the central node 23 together with the second terminal 27b of the resistor circuit 27. The first terminal 13a of the first capacitor 13 is connected to the first terminal 10 of the filter device 8. The first terminal 15a of the second capacitor 15 is connected to the second terminal 11 of the filter device 8.

[0083] In the third exemplary embodiment, the resistance value R1 of the first resistor component 19 is also smaller than the resistance value R2 of the second resistor component 20, and the switching device 21 is configured to switch the switch 27 on to adopt the first filter mode and to switch the switch 27 off to adopt the second filter mode.

[0084] In the third exemplary embodiment, a third capacitor 26 is connected in parallel with the first and second capacitors 13,15.

[0085] According to FIG. 2, in the third exemplary embodiment, the resistor circuit 27 is arranged on a printed circuit board 50 .

[0086] In the fourth exemplary embodiment, which corresponds to the third exemplary embodiment, the resistor circuit 27 is designed according to the resistor circuit 17 according to the second embodiment. In other words, the switch 28 forms a parallel circuit with the second resistor component 20, and the first resistor component 19 is connected in series with this parallel circuit.

[0087] According to a further exemplary embodiment corresponding to the first or second exemplary embodiment, a third resistor circuit 27 according to a third or fourth exemplary embodiment is further provided.

[0088] According to a further exemplary embodiment corresponding to one of the aforementioned exemplary embodiments, it is also possible to combine a resistor circuit 17, 18 according to the first exemplary embodiment between one of the capacitors 13, 15 and the central node 23 with a resistor circuit 17, 18 according to the second exemplary embodiment between the other of the capacitors 13, 15 and the central node.

[0089] FIG. 5 is a block diagram of one exemplary embodiment of an onboard electrical system 101 within a vehicle 100 .

[0090] 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 22. 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.

[0091] 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.

[0092] The on-board electrical system 101 comprises a further power converter 1 a according to one of the exemplary embodiments described above, 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.

[0093] The on-board electrical system 101 comprises a further power converter 1b according to one of the exemplary embodiments described above, 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, for example 12 volts, 24 volts or 48 volts.

[0094] 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 22 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 22 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.

[0095] 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.

[0096] 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) connected to a first current path (14) from the first terminal (10) to the third terminal (12) and affecting a first impedance along the first current path (14) to dissipate common mode currents associated with the first and second lines (4, 5) towards the third terminal (12); a second capacitor (15) connected to a second current path (16) from the second terminal (11) to the third terminal (12) and affecting a second impedance along the second current path (16) to dissipate the common mode current towards the third terminal (12); a switching device (21) configured to switch between a first filter mode and a second filter mode based on control information (22); and a filter device (8) having The filter device (8) comprises at least one resistor circuit (17, 18, 27) having a first resistor component (19) and a second resistor component (20), and the switching device (21) changes the interconnection of the resistor components (19, 20) within the filter device (8), thereby - in said first filter mode, to provide a predefined absolute value for each of said first impedance and said second impedance; and - in said second filter mode, providing each of said first impedance and said second impedance with a predefined absolute value that is increased compared to said first filter mode; A power converter (1, 1a, 1b) for an on-board electrical system (101) of an electrically drivable vehicle (100), further comprising:

2. the filter device (8) is configured to set a time constant of a low-pass filter formed by the capacitor (13, 15) and the at least one resistor circuit (17, 18, 27) higher in the second filter mode than in the first filter mode in order to filter the common-mode current along the first current path (14) and the second current path (16), respectively.

10. The power converter of claim 1.

3. The filter device (8) has a central node (23) located between the first capacitor (13) and the second capacitor (15).

3. The power converter according to claim 1 or 2.

4. the resistor circuit (27) is connected to a circuit branch between the central node (23) and the third terminal (12); 4. The power converter of claim 3.

5. a resistor circuit (17) is connected in series with the first capacitor (13) in the circuit branch between the first terminal (10) and the central node (23); and / or a resistor circuit (18) is connected in series with said second capacitor (15) in the circuit branch between said second terminal (11) and said central node (23); 5. The power converter according to claim 3 or 4.

6. the at least one resistor circuit (17, 18, 27) is connected to a terminal (13b, 15b) of the first capacitor (13) or the second capacitor (15b) facing the central node (23); 6. A power converter according to any one of claims 3 to 5.

7. 7. A power converter according to any one of the preceding claims, wherein the switching device (21) comprises a switch (24, 25, 28) for the or each resistor circuit.

8. The switches (24, 25, 28) form a series circuit with the first resistor component (19), and the second resistor component (20) is connected in parallel with the series circuit.

8. The power converter of claim 7.

9. The switches (24, 25) form a parallel circuit with the second resistor component (20), and the first resistor component (19) is connected in series with the parallel circuit.

8. The power converter of claim 7.

10. the switching device (21) is configured to switch the switches (24, 25, 28) on to adopt the first filter mode and / or switch the switches (24, 25, 28) off to adopt the second filter mode; 10. A power converter according to any one of claims 7 to 9.

11. the resistance value of the first resistor component (19) is less than the resistance value of the second resistor component (20); 11. A power converter according to any one of claims 1 to 10.

12. the filter device (21) further includes a third capacitor (26) connected to the first terminal (10) and the second terminal (11) in parallel with the first and second capacitors (13, 15); 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 capacitor (13), the second capacitor (14) and the at least one resistor circuit (17, 18, 27) 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 (21) is arranged on the 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 the opposite side of the DC link capacitor (40) from 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 (22) for adopting the second filter mode when and / or as long as the charging device (103) is connected to the power supply system (103) external to the vehicle. An on-board electrical system (101).

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