Current-compensated choke, filter, high-voltage electrical system and motor vehicle

Abstract

The invention relates to a current-compensated choke (11) for filtering interference signals transmitted between two high-voltage components (8, 9) of a high-voltage electrical system (7) of a motor vehicle, comprising a toroidal, in particular annular or oval-ring-shaped, magnetic core (12) enclosing an inner opening (13) and comprising at least two busbars (14) for electrically connecting the two high-voltage components (8, 9), wherein the busbars (14) are axially guided through the inner opening (13) of the magnetic core (12) and are spaced apart from each other in the inner opening (13) forming an air gap (17), and wherein an inner side (15) of the magnetic core (12) facing the inner opening (13) and areas (16a) of outer sides (16) of the busbars (14) facing the inner side (15) of the magnetic core (12) have corresponding shapes. The invention also relates to a filter (10), a high-voltage electrical system (7) and a motor vehicle.

Description

[0001] The invention relates to a current-compensated choke for filtering interference signals transmitted between two high-voltage components of a high-voltage electrical system of a motor vehicle, comprising a toroidal magnetic core enclosing an inner opening and at least two busbars for electrically connecting the two high-voltage components. The busbars extend axially through the inner opening of the magnetic core and are arranged spaced apart from one another in the inner opening, forming an air gap. The invention also relates to a filter, a high-voltage electrical system, and a motor vehicle.

[0002] In this case, the focus is on EMC (electromagnetic compatibility) filters for high-voltage electrical systems of electrically powered motor vehicles, such as electric or hybrid vehicles. Such filters can include, for example, current-compensated chokes or common-mode chokes (CMC), which can be used to attenuate interference signals transmitted between two high-voltage components of the high-voltage electrical system. Such current-compensated chokes can, for example, as shown in DE 10 2017 108 383 A1, have a toroidal magnetic core, in particular a ring core, which is plugged onto busbars for electrically connecting the high-voltage components.

[0003] In Fig. 1a to Fig. 1d shows cross sections of current-compensated chokes 1 according to the prior art. The choke 1 according to Fig. 1a and Fig. 1b has a magnetic core 2 with a circular cross-section and the choke 1 according to Fig. 1c and Fig. 1d has a magnetic core 2 with an oval-ring-shaped cross-section. Busbars 4 are arranged in an inner opening 3 of the magnetic core 2 extending in the axial direction (into the plane of the drawing), wherein the busbars 4 are arranged according to Fig. 1a and Fig. 1d each have a circular cross-section and the busbars 4 according to Fig. 1 b and Fig. 1 c each have a rectangular cross-section.

[0004] Due to the rectangular or circular cross-sections of the busbars 4, the utilization of the volume of the inner opening 3, i.e., the internal volume, is not optimal. In particular, large distances arise between an inner side 5 of the magnetic core 2 facing the inner opening 3 and regions of the outer sides 6 of the busbars 4 facing the inner side 5 of the magnetic core 2. This results in a comparatively low inductance of the choke 1, which can be increased by extending the depth of the magnetic core in the axial direction. However, this is associated with increased material requirements and thus with increased costs, increased installation space requirements, and increased weight.

[0005] Furthermore, DE 29 23 096 A1 discloses a compensating transformer for a protective device in electrical systems, which comprises a toroidal core and at least two primary conductors. The part of each primary conductor located inside the toroidal core has a geometric shape adapted to the inner surface of the toroidal core. Magnetic core components are also known from US 3 031 736 A and US 2013 / 0 278 368 A1.

[0006] It is an object of the present invention to provide a cost-effective, material-, space- and weight-saving current-compensated choke for a high-voltage on-board network of an electrically driven motor vehicle.

[0007] This object is achieved according to the invention by a current-compensated choke, a filter, a high-voltage electrical system, and a motor vehicle having the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0008] A current-compensated choke according to the invention serves to filter interference signals transmitted between two high-voltage components of a high-voltage electrical system of a motor vehicle. The choke has a toroidal magnetic core enclosing an inner opening and busbars for electrically connecting the two high-voltage components. The at least two busbars extend axially through the inner opening of the magnetic core and are arranged spaced apart from one another in the inner opening, forming an air gap. Furthermore, an inner side of the magnetic core facing the inner opening and regions of the outer sides of the busbars facing the inner side of the magnetic core have corresponding shapes.

[0009] The current-compensated choke can be arranged, for example, in a power transmission path between two high-voltage components in the form of a traction battery and an inverter, or in the form of an inverter and an electric drive motor. The choke is designed to at least attenuate interference signals transmitted via the power transmission path. For this purpose, the two high-voltage components are electrically connected to one another at least indirectly via the choke's busbars, with the choke having a number of busbars corresponding to a number of phases of the power transmission path.

[0010] The toroidal magnetic core or ring core is placed onto the busbars so that the busbars are surrounded by the magnetic core along an axial section. A toroidal magnetic core is understood to mean, in particular, a circular ring magnetic core or an oval ring magnetic core. At least a first region of the outer side of a busbar faces the inner side of the magnetic core, and at least a second region of the outer side of a busbar faces the air gap and thus an adjacent busbar. The air gap serves to electrically insulate the busbars from one another and can, for example, also be filled at least partially with an electrically insulating material. The busbars are shaped such that the first regions of the outer sides, which face the magnetic core, correspond to a profile of the inner side of the magnetic core.Viewed in cross-section, a linear shape of an outer circumferential section of the busbar cross-section follows a linear shape of an inner circumference of the magnetic core cross-section. In other words, the outer circumferential section of the busbar cross-section and the inner circumference of the magnetic core cross-section are oriented essentially parallel to one another. The busbar cross-section is therefore adapted to the shape of the magnetic core cross-section or to a shape of the inner opening influenced by the magnetic core cross-section. The busbar cross-section and the magnetic core cross-section thus have matching shapes. The outer side of the busbars facing the magnetic core can, for example, be fully pressed against the inner surface of the magnetic core or can be arranged with a small air gap spaced from the inner surface of the magnetic core.

[0011] The matched cross-sectional shapes of the busbars and the magnetic core allow for optimal utilization of the magnetic core's internal volume by filling the internal opening with the busbars to the maximum. This allows for the manufacture of a choke whose only unused area of ​​the internal volume is formed by the necessary air gap between the busbars. This allows for a choke whose inductance can be adjusted to a high value with minimal material expenditure, minimal space requirements, low weight, and low cost.

[0012] It proves advantageous if the inside of the magnetic core is formed from an electrically insulating material, and the areas of the outer sides of the busbars facing the inside of the magnetic core are arranged so that they fully abut the inside of the magnetic core. The magnetic core can be formed, for example, from thin, mutually insulated iron sheets or from nanoparticles cast in plastic, with the inside being electrically insulating. Thus, the busbars can be arranged in the inner opening of the magnetic core by contacting the inside of the magnetic core, maximizing the volume utilization.

[0013] The inner side of the magnetic core has a concave shape, at least in sections, and the areas of the outer sides of the busbars facing the concave inner side of the magnetic core have a convex shape. The concave inner side of the magnetic core and the convex outer sides of the busbars have the same radius of curvature. This allows the inner side of the magnetic core and the outer sides of the busbars to be arranged adjacent to one another, for example.

[0014] According to a first embodiment not claimed here, the magnetic core has a circular cross-section that encloses the inner opening in a circle to form the concavely shaped inner side. It can be provided that the choke has exactly two busbars, which have circular segment-shaped cross-sections to form the convexly shaped regions of the outer side and which are arranged in the inner opening to form a strip-shaped air gap. The toroidal magnetic core is therefore designed here as a circular ring magnetic core or annular ring magnetic core. The circular segment-shaped cross-section of the busbars is delimited by a circular arc and a chord. The circular arc corresponds to the first region of the outer side of the busbar facing the inner side of the magnetic core, which region can, for example, be applied to the inner side of the magnetic core.The chord of the circle corresponds to the second area of ​​the outer side of the busbar facing the air gap. The two opposite circular segment-shaped busbar cross-sections and the air gap form a circle.

[0015] The choke can also be provided with three busbars, which have circular sector-shaped cross-sections to form the convex outer areas and which are arranged in the inner opening to form a star-shaped air gap. The circular inner opening can thus be divided into three circular sectors, with a busbar with a circular sector-shaped or pie-shaped cross-section being arranged in each circular sector. The cross-sectional areas of the busbars are smaller than the areas of the circular sectors, so that the busbars are arranged at a distance from one another to form the star-shaped, Y-shaped air gap.

[0016] In addition, to form the concavely shaped interior, the magnetic core has an oval-ring-shaped cross-section that encloses the inner opening, with two opposing circular arc sections and two opposing straight-line sections. The toroidal magnetic core is thus designed here as an oval-shaped ring magnetic core or an oval ring magnetic core. The inner circumference of the magnetic core cross-section thus has an oval shape, with the circular arc sections connected to each other via the straight-line sections. In other words, the inner circumference has an elliptical shape that is flattened or uncurved along the main axis of the ellipse.

[0017] According to a second embodiment, not claimed here, the choke has precisely two busbars, which have circular-segment-shaped cross-sectional areas to form the convex-shaped areas of the outer side and are arranged on the circular arc sections of the inner side of the magnetic core, forming a strip-shaped air gap. The circular-segment-shaped cross-sectional area can, for example, also be semicircular. For example, depending on the length of the straight-line sections, the busbars can have a circular-segment-shaped cross-section or a cross-section formed by a circular-segment-shaped area and a rectangular area.In the first case, the area of ​​the outside of a busbar facing the air gap is arranged at a transition between the circular arc section and the straight section of the inside of the magnetic core and in the second case, the area of ​​the outside of a busbar facing the air gap is arranged in the area of ​​the straight section.

[0018] According to the invention, the choke has three busbars arranged spaced apart from one another along the straight-line sections, forming two strip-shaped air gaps. The two outer busbars have circular-segment-shaped cross-sectional areas to form the convex-shaped areas of the outer side, and the inner busbar has a rectangular cross-section. The two outer busbars are thus rounded in some areas so that they can be arranged precisely in the area of ​​the circular arc sections. The middle, inner busbar is arranged in the area of ​​the straight-line sections and has straight, unbent areas of the outer side for arrangement on the straight-line sections.

[0019] The invention also relates to a filter for a high-voltage electrical system of an electrically powered motor vehicle with at least one current-compensated choke according to the invention. The filter is designed to at least attenuate interference signals in the signal transmission path between the high-voltage components.

[0020] The invention further relates to a high-voltage electrical system for an electrically driven motor vehicle, comprising at least two high-voltage components and a filter according to the invention, wherein the two high-voltage components are electrically connected to one another via the busbars of the choke. The high-voltage components can, for example, be components of an electric drive unit of the motor vehicle. For example, the high-voltage components can be a traction battery, an inverter, and / or a drive motor.

[0021] A motor vehicle according to the invention comprises a high-voltage electrical system according to the invention. The motor vehicle is designed, in particular, as an electric or hybrid vehicle.

[0022] The embodiments presented with reference to the current-compensated choke according to the invention and their advantages apply accordingly to the filter according to the invention, to the high-voltage vehicle electrical system according to the invention and to the motor vehicle according to the invention.

[0023] Further features of the invention emerge from the claims, the figures and the description of the figures.

[0024] The invention will now be explained in more detail using a preferred embodiment and with reference to the drawings.

[0025] They show: Fig. 1a to Fig. 1d schematic cross-sectional views of current-compensated chokes according to the prior art; Fig. 2 a schematic representation of an embodiment of a high-voltage electrical system according to the invention, and Fig. 3a to Fig. 3c schematic cross-sectional views of embodiments of current-compensated chokes, wherein the Fig. 3a and Fig. 3c show unclaimed embodiments.

[0026] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0027] Fig. 2 shows a high-voltage electrical system 7 for an electrically powered motor vehicle (not shown here). The high-voltage electrical system 7 has two electrically interconnected high-voltage components 8, 9. The high-voltage component 8 can be, for example, a traction battery of the electrically powered motor vehicle, and the high-voltage component 9 can be, for example, an inverter of the motor vehicle. The high-voltage components 8, 9 are electrically coupled to one another via a filter 10, which is designed to at least attenuate interference signals transmitted between the high-voltage components 8, 9. The filter 10 has at least one current-compensated choke 11.

[0028] In Fig. 3a to Fig. 3c shows cross-sectional views of different embodiments of a current-compensated choke 11 according to the invention. The choke 11 has a magnetic core 12 which is extruded in the axial direction (into the plane of the drawing). Busbars 14, which also extend in the axial direction, are arranged within an inner opening 13 of the magnetic core 12. Along the axial direction, a section of the busbars 14 is surrounded by the magnetic core 12. The magnetic core 12 is thus plugged onto the busbars 14. An inner side 15 of the magnetic core 12 facing the inner opening 13 and first regions 16a of outer sides 16 of the busbars 14, which face the inner side 15 of the magnetic core 12, have corresponding shapes.The inner side 15 of the magnetic core 12 can, for example, be formed from an electrically insulating material, so that the first regions 16a of the outer side 16 of the busbars 14 here lie fully against the inner side 15 of the magnetic core 12. Second regions 16b of the outer sides 16 of the busbars 14 face an air gap 17 or an electrically insulating region between the busbars 14. The inner side 15 of the magnetic core 12 is concave in shape, at least in some areas, while the first regions 16a of the busbars 14 are concave in shape, matching this, at least in some areas.

[0029] In the unclaimed embodiment of the throttle 11 according to Fig. 3a, the magnetic core 12 has a circular cross-section 18, so that the inner opening 13 is circular. In addition, the choke 11 according to Fig. 3a comprises three busbars 14, which have circular sector-shaped cross-sections 19. The convex-shaped first regions 16a of the outer side 16 and the concave-shaped inner side 15 of the magnetic core 12 have the same radius of curvature, so that the first regions 16a of the busbars can be applied over their entire surface to the inner side 15 of the magnetic core 12. The three circular sector-shaped cross-sections 19 of the busbars 14 have, in particular, equally large areas. The air gap 17 between the circular sector-shaped cross-sections 19 of the busbars 14 is star-shaped. With the same inductance, the amount of material of such a choke 11 is Fig. 3b is approximately 2.5 times smaller than the amount of material of the throttle 1 according to Fig. 1b, in which the busbars 4 have rectangular cross-sections. A depth of the magnetic core 2 of the choke 1 according to Fig. 1 b in the axial direction must therefore be approximately 2.5 times larger to set the same inductance as the choke 11 according to Fig. 3a.

[0030] In the embodiment of the throttle 11 according to Fig. 3b, the magnetic core 12 has an oval-shaped cross-section 20 with two opposite circular arc sections 21 and two opposite straight sections 22. As a result, the inner opening 15 is oval. The choke 11 according to Fig. 3b also has three busbars 14, with two outer busbars 14 being arranged in the region of the circular arc sections 21 and a middle busbar 14 being arranged in the region of the straight section sections 22. The two outer busbars 14 each have a circular segment-shaped cross-sectional area 23 and a rectangular cross-sectional area 24, with the circular segment-shaped cross-sectional area 23 forming the convex shape of the first area 16a of the outer side 16 of the busbar 14. The middle busbar 14 has a rectangular cross-section 25. The first area 16a of the outer side 16 of the middle busbar 14 thus has straight edges facing the straight section sections 22. The volume of the inner opening 13 is utilized significantly more here than the internal volume of the inner opening 3 of the choke 1 according to Fig. 1c, in which the busbars 4 have rectangular cross-sections.

[0031] In the unclaimed embodiment of the throttle 11 according to Fig. 3c, the magnetic core 12 also has an oval-ring-shaped cross-section 20, but the straight section sections 22 are shorter than the straight section sections 22 of the choke 11 according to Fig. 3b. The throttle 11 according to Fig. 3c has two busbars 14, which have circular segment-shaped cross sections 26 to form the convex shape. The circular segment-shaped cross sections 26 are arranged spaced apart from one another in the region of the circular arc sections 21 of the magnetic core 12 and form a strip-shaped air gap 17. List of reference symbols 1 throttle 2 magnetic core 3 Internal opening 4 busbars 5 Inside 6 Outside 7 High-voltage electrical system 8.9 High-voltage components 10 filters 11 Throttle 12 magnetic core 13 Interior opening 14 Busbar 15 Inside 16 Outside 16a, 16b Areas of the outside 17 Air gap 18 circular cross-section 19 circular sector-shaped cross-section 20 oval ring-shaped cross-section 21 circular arc sections 22 straight sections 23 circular segment-shaped cross-sectional area 24 rectangular cross-sectional area 25 rectangular cross-section 26 circular segment-shaped cross-section

Claims

[1] Current-compensated choke (11) for filtering interference signals transmitted between two high-voltage components (8, 9) of a high-voltage on-board network (7) of a motor vehicle, with a toroidal magnetic core (12) enclosing an inner opening (13) and with at least two busbars (14) for electrically connecting the two high-voltage components (8, 9),wherein the busbars (14) are guided axially through the inner opening (13) of the magnetic core (12) and are arranged at a distance from one another in the inner opening (13) to form an air gap (17), and wherein an inner side (15) of the magnetic core (12) facing the inner opening (13) and regions (16a) of outer sides (16) of the busbars (14) facing the inner opening (13) and the inner side (15) of the magnetic core (12) have corresponding shapes, and for this purpose the inner side (15) of the magnetic core (12) has a concave shape at least in sections, and the regions (16a) of the outer sides (16) of the busbars (14) facing the concavely shaped inner side (15) of the magnetic core (12) have a convex shape for full-surface contact with the inner side (15) of the magnetic core (12), wherein the concavely shaped inner side (15) of the magnetic core (12) and the convex-shaped regions (16a) of the outer sides (16) of the busbars (14) have the same radius of curvature,wherein the magnetic core (12) has an oval-ring-shaped cross-section (20) which surrounds the inner opening (13) in an oval manner, with two opposite circular arc sections (21) and two opposite straight-line sections (22), for forming the concavely shaped inner side (15), wherein the choke (11) has three busbars (14) which are arranged at a distance from one another along the straight-line sections (22) to form two strip-shaped air gaps (17), wherein the two outer busbars (14) have circular-segment-shaped cross-sectional areas (23) for forming the convexly shaped areas (16a) of the outer side (16), and the inner busbar (14) has a rectangular cross-section (25). [2] Current-compensated choke (11) according to claim 1, characterized bythat the inner side (15) of the magnetic core (12) is formed from an electrically insulating material and the regions (16a) of the outer sides (16) of the busbars (16) facing the inner side (15) of the magnetic core (12) are arranged so as to bear fully against the inner side (15) of the magnetic core (12). [3] Filter (10) for a high-voltage electrical system (7) of a motor vehicle, comprising a current-compensated choke (11) according to one of the preceding claims. [4] High-voltage on-board network (7) for an electrically driven motor vehicle comprising at least two high-voltage components (8, 9) and a filter according to claim 3, wherein the two high-voltage components (8, 9) are electrically connected to one another via the busbars (14) of the choke (11). [5] Motor vehicle with a high-voltage electrical system (7) according to claim 4.

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