Throttle system for reducing DC currents in AC drive systems and vehicles with this

Abstract

AC choke (24) for reducing common-mode and bearing currents in AC drive systems, comprising: a magnetic core (26) defining an axial bore (40); a dielectric separator (30) surrounding the magnetic core (26); a metal housing (34) surrounding the dielectric separator (30); a first layer of a thermal interface material arranged between the magnetic core (26) and the dielectric separator (30); a second layer of the thermal interface material arranged between the dielectric separator (30) and the metal housing (34); a dielectric outer sheath (38) surrounding the metal housing (34); and a third layer of thermal interface material arranged between the metal casing (34) and the dielectric outer sheath (38); wherein the dielectric separator (30) electrically isolates the magnetic core (26) from the metal casing (34).

Description

INTRODUCTION

[0001] This disclosure relates to AC chokes for use in fully electric or hybrid electric motor vehicles and other electrical applications requiring a reduction of common-mode and bearing currents in AC drive systems using shielded cables.

[0002] Fully electric and / or hybrid electric vehicles can use AC traction drive units (TDUs) to power the vehicle. A DC / AC module can be used to supply the TDUs with alternating current. High-frequency (up to about 10 MHz) electromagnetic interference can originate from an electric vehicle's AC system (e.g., from the inverter module), which can disrupt radio, sensor, control, and computer operations in the vehicle. AC chokes, made of an iron-based material, can be used to reduce or attenuate high-frequency common-mode and bearing currents in current-carrying conductors or buses. Overheating of the magnetic core of an AC choke can decrease the core's magnetic permeability and reduce the choke's shielding performance. DESCRIPTION

[0003] This disclosure addresses common-mode and bearing currents in AC drive systems by using an AC choke assembly integrated into shielded electrical coaxial cables. This design mitigates common-mode currents and ensures electromagnetic compatibility. The AC choke has a magnetic core that defines an axial bore for receiving the electrical coaxial cables. The cables are enclosed in a metal housing and insulated by a dielectric separator. An optional dielectric outer cover can further insulate the metal housing. Thermal paste can be used to optimize heat conduction between the different layers of the AC choke. One side of the metal housing is connected to a first set of coaxial cable shields, and the other side can be connected to a traction drive unit (TDU) or a traction power inverter module (TPIM).Alternatively, the AC choke can also be located in a middle section of the coaxial cables.

[0004] The methods and devices disclosed herein address the reduction of common-mode and bearing currents in a vehicle's electric drive system. The disclosure describes an AC choke assembly that effectively reduces and mitigates common-mode currents in AC drive systems. This helps reduce electrical noise and interference, leading to improved system performance and reliability. The use of a metal housing for the AC choke assembly effectively reduces electromagnetic interference (EMI). This contributes to compliance with EMC regulations and standards and ensures that the system operates without interference from other electronic devices in the vehicle. The use of thermally conductive materials in the AC choke assembly helps maximize thermal conductivity between adjacent layers.This improves heat dissipation from the AC choke, preventing overheating and ensuring optimal system performance and longevity. The presented designs allow for easy integration of the AC choke into the electrical coaxial cable system of AC drive systems. Options are provided for connecting the metal housing to the coaxial cable shield or for connecting the magnetic core to the coaxial cable shield (i.e., to the shield ends), offering flexibility in system design and installation. The AC choke can be positioned over an unshielded portion of the electrical coaxial cable, reducing the mean magnetic length of the choke assembly and resulting in higher system magnetic inductance (and thus improved electromagnetic shielding).Typical alternating current frequencies range from 1 to 10 MHz.

[0005] In a first embodiment, an AC choke for reducing common-mode and bearing currents in AC drive systems comprises a magnetic core defining an axial bore within the magnetic core, a dielectric separator surrounding the magnetic core, and a metal housing surrounding the dielectric separator. The dielectric separator electrically isolates the magnetic core from the metal housing. The AC choke may further comprise a first gap arranged between the magnetic core and the dielectric separator, a second gap arranged between the dielectric separator and the metal housing, a first layer of a thermal interface material filling the first gap, and a second layer of the thermal interface material filling the second gap. An optional dielectric outer sheath may surround the metal housing.An optional third layer of thermal interface material can be positioned between the metal housing and the optional dielectric outer sheath. The magnetic core can be a ferrite material or a nanocrystalline iron material. The dielectric separator and the optional dielectric outer sheath can be a semi-crystalline, thermoplastic high-temperature polymer material (e.g., polyphenylene sulfide (PPS)). The metal housing can be an aluminum alloy and / or a steel alloy.

[0006] In some embodiments, the magnetic core can have a rectangular, rounded rectangular, circular, triangular or rounded triangular shape.

[0007] In some embodiments, the magnetic core can be made from a variety of nanocrystalline iron strips wound in a rounded rectangular geometry, with an axial bore arranged inside the magnetic core.

[0008] In some embodiments, the AC choke has at least one electrical coaxial cable located in and passing through the bore inside the magnetic core. Each electrical coaxial cable comprises an axial central conductor, a coaxial dielectric insulator surrounding the axial central conductor, a conductive coaxial shield surrounding the coaxial dielectric insulator, and a dielectric coaxial jacket surrounding the conductive coaxial shield. In some embodiments, the AC choke is located in a central section of an electrical coaxial cable.

[0009] In some embodiments, the AC choke is located at one end of an electrical coaxial cable.

[0010] In some embodiments, the conductive coaxial shield is electrically connected to an outer surface of the metal housing of the AC choke. In other embodiments, the conductive coaxial shield is electrically connected to an inner surface of the metal housing of the AC choke.

[0011] In some embodiments, a portion of the dielectric coaxial sheath and the conductive coaxial shield is peeled away from the at least one electrical coaxial cable, defining an exposed portion of the conductive coaxial shield and thus an unshielded axial portion of the at least one electrical coaxial cable. The conductive coaxial shield may be discontinuous along an unshielded axial section. The AC choke may be positioned across the unshielded axial section of the electrical coaxial cable.

[0012] In some embodiments, the metal housing of the AC choke is electrically connected to a metal housing of a TDU, and the conductive coaxial shield is connected to the metal housing.

[0013] In some embodiments, the metal housing of the AC choke is electrically connected to a metal housing of a TPIM, and the conductive coaxial shield is connected to the metal housing.

[0014] In some embodiments, the conductive coaxial shield is connected to the magnetic core, and the metal housing and dielectric separator are not present.

[0015] In some embodiments, three parallel electrical coaxial cables are located inside the bore in the magnetic core of the AC choke and pass through it.

[0016] In some embodiments, an AC choke assembly includes a TDU that is connected to the metal housing of the AC choke.

[0017] In some embodiments, a system for reducing common-mode and bearing currents in AC drive systems comprises an AC drive system with an AC traction motor and associated power electronics connected via one or more electrical coaxial cables, and an AC choke assembly integrated into one or more electrical coaxial cables to reduce common-mode currents and ensure EMC.

[0018] In some embodiments, an AC drive system comprises an AC choke with one or more electrical coaxial cables passing through the AC choke and connected to a TDU configured for use in an electric vehicle.

[0019] In some embodiments, an AC drive system comprises an AC choke with one or more electrical coaxial cables passing through the AC choke and connected to a TPIM configured for use in an electric vehicle.

[0020] In some embodiments, the exposed surfaces of the AC choke are covered with a dielectric insulating material.

[0021] In some embodiments, the metal housing is omitted, and the conductive coaxial shield is connected to the magnetic core of the AC choke.

[0022] In some embodiments, a vehicle comprises a vehicle body, one or more wheels connected to the vehicle body, and an AC choke assembly connected to the vehicle body. The AC choke assembly comprises an AC choke, at least one electrical coaxial cable located inside and passing through the AC choke, and a traction drive unit (TDU) or traction power inverter module (TPIM) connected to the AC choke. The AC choke has a magnetic core, an axial bore defined by the magnetic core, a dielectric separator surrounding the magnetic core, and a metal housing surrounding the dielectric separator. The dielectric separator electrically isolates the magnetic core from the metal housing.The at least one electrical coaxial cable has an axial central conductor, a coaxial dielectric insulator surrounding the axial central conductor, a conductive coaxial shield surrounding the coaxial dielectric insulator, and a dielectric coaxial jacket surrounding the conductive coaxial shield.

[0023] The axial central conductor is connected to the TDU or TPIM, and the conductive coaxial shield is connected to the metal housing. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1A shows an example of an electrical coaxial cable in a perspective sectional view. Fig. Figure 1B shows a perspective sectional view of an electrical coaxial cable in which a section of the central axial conductor is exposed at one end. Fig. Figure 2A shows a schematic perspective cross-sectional view of an example of a rectangular AC choke according to the present disclosure. Fig. Figure 2B shows a schematic perspective cross-sectional view of an example of a rectangular AC choke assembly with three parallel electrical coaxial cables arranged therein, according to the present disclosure. Fig. Figure 3A shows a schematic perspective view of an example of a monolithic, rectangular magnetic core with rounded corners according to the present disclosure. Fig. Figure 3B shows a schematic perspective view of an example of a monolithic, rectangular magnetic core assembly with rounded corners and three parallel electrical coaxial cables arranged therein, according to the present disclosure. Fig. Figure 4A shows a schematic perspective cross-sectional view of an example of a rectangular AC choke with rounded corners according to the present disclosure. Fig. Figure 4B shows a schematic perspective cross-sectional view of an example of a rectangular AC choke assembly with rounded corners and three parallel electrical coaxial cables arranged therein, according to the present disclosure. Fig. Figure 5A shows a schematic perspective cross-sectional view of an example of a circular AC choke according to the present disclosure. Fig. Figure 5B shows a schematic perspective cross-sectional view of an example of a circular AC choke assembly with three parallel electrical coaxial cables arranged therein, according to the present disclosure. Fig. Figure 6A shows a schematic perspective cross-sectional view of an example of a triangular AC choke according to the present disclosure. Fig. Figure 6B shows a schematic perspective cross-sectional view of an example of a triangular AC choke assembly with three parallel electrical coaxial cables arranged therein, according to the present disclosure. Fig. Figure 7 shows a schematic top view of an example of an AC choke assembly comprising an AC choke with three parallel, coaxial electrical coaxial cables arranged inside the AC choke and extending through it in the direction of the Z-axis, according to the present disclosure. Fig. 8A shows a schematic lateral cross-sectional view (section AA) of the in Fig. 7 shown example of an electrical coaxial cable which is electrically and mechanically connected to an AC choke according to the present disclosure. Fig. Figure 8B shows a schematic lateral cross-sectional view (section AA) of the in Fig. 7 shown example of an electrical coaxial cable which is electrically and mechanically connected to an AC choke according to the present disclosure. Fig. Figure 9A shows a schematic top view of an example of an AC choke attached either to a traction drive unit (TDU) or to a traction power inverter module (TPIM), with three parallel electrical coaxial cables arranged inside the AC choke and running through it in the direction of the Z-axis, according to the present disclosure. Fig. Figure 9B shows a schematic top view of an example of an AC choke attached either to a traction drive unit (TDU) or to a traction power inverter module (TPIM), with three parallel electrical coaxial cables arranged inside the AC choke and running through it in the direction of the Z-axis, according to the present disclosure. Fig. Figure 10 shows a schematic lateral cross-sectional view (section BB) of the in Fig. 9A example of an electrical coaxial cable which is electrically and mechanically integrated with an AC choke attached to a TPIM or TDU power unit, according to the present disclosure. Fig. Figure 11A shows a schematic top view of an example of an AC choke housed in a sheet metal casing, according to the present disclosure. Fig. Figure 11B shows a schematic bottom view of an example of an AC choke housed in a sheet metal casing, according to the present disclosure. Fig. Figure 11C shows a schematic front view of an example of an AC choke housed in a sheet metal casing, according to the present disclosure. Fig. Figure 11D shows a schematic side view of an example of an AC choke housed in a sheet metal casing, according to the present disclosure. Fig. Figure 12 shows a schematic cross-sectional view in front view of a magnetic core of an AC choke according to the present disclosure. Fig. Figure 13 shows a schematic perspective view of an example of a triangular magnetic core of an AC choke according to the present disclosure. Fig. Figure 14 shows a schematic perspective view of an example of a vehicle with an AC choke according to the present disclosure. DETAILED DESCRIPTION OF THE REVELATION

[0024] The AC chokes disclosed herein can be used in a variety of mobile electric or hybrid-electric applications, including but not limited to: automobiles, trucks, motorcycles, boats, submarines, aircraft, jets, spacecraft, trains, or other mobile platforms, as well as non-mobile electrical systems such as power plants, appliances, and photovoltaic solar installations. The term "vehicle" is defined in the broadest sense as any moving machine, including but not limited to: automobiles, trucks, motorcycles, boats, submarines, aircraft, spacecraft, trains, or other mobile platforms.

[0025] Fig. Figure 1A shows a perspective sectional view of an electrical coaxial cable 10. The cable 10 comprises the following layers: an electrically conductive axial central conductor 12 (e.g., a thick solid copper wire or a thin copper strand) covered by a coaxial dielectric insulator 14, which is covered by a first conductive coaxial shield 16 (which may have a braided arrangement of conductive aluminum or copper wires), which is optionally covered by a second conductive shielding layer 18 (e.g., aluminum foil), which is finally covered by a dielectric coaxial jacket 20 (which may have a dielectric insulating material).

[0026] Fig. Figure 1B shows a simplified perspective view of an example of an electrical coaxial cable 10, in which part of the axial central conductor 12 is exposed at one end. In this example, the coaxial dielectric insulator 14, the conductive coaxial shield 16, and the dielectric coaxial sheath 20 have been partially stripped and removed, leaving part of the axial central conductor 12 exposed.

[0027] Fig. Figure 2A shows a schematic perspective cross-sectional view of an example of a rectangular AC choke 24 according to the present disclosure. The choke 24 has a rectangular shape with an axial length = L (in the direction of the Z-axis). The choke 24 has a hollow magnetic core 26 made of an iron-based magnetochemical material (e.g., iron-based iron or ferrite material, or nanocrystalline amorphous iron-based ribbon material) that defines a rectangular bore 40 inside the magnetic core 26. Outwardly, the next layer comprises a first layer of a thermally conductive material 28 (e.g., thermal paste). Outwardly, the next layer comprises a dielectric separator 30 made of a dielectric material (e.g., polyamide, polyphenylene sulfide, epoxy resin, and / or polycarbonate, etc.). On the outside, the next layer has a second layer made of a thermally conductive material 32 (e.g.The first layer consists of thermally conductive paste). The next layer has a metal casing 34 (e.g., an aluminum or steel alloy or a combination thereof). The third layer has a thermally conductive material 36 (e.g., thermal paste). Finally, the outermost layer of the choke 24 has a dielectric outer sheath 38 made of an insulating material (e.g., polyamide, polyphenylene sulfide, epoxy resin and / or polycarbonate, etc.).

[0028] As in Fig. As shown in Figure 2A, in some embodiments the third layer of thermally conductive material 36 (e.g., thermal paste) and the dielectric outer sheath 38 can be omitted. In this embodiment, the metal housing 34 is the outermost layer.

[0029] Fig. Figure 2B shows a schematic perspective cross-sectional view of an example of a rectangular AC choke assembly 42 with an axial length = L (in the direction of the Z-axis) with three parallel electrical coaxial cables 44, 44' and 44", which are arranged within and pass through the bore 40 of the choke 24, according to the present disclosure. The remaining unused open space 22 between the electrical coaxial cables 44, 44' and 44" may, in some embodiments, be filled with a dielectric material.

[0030] Fig. Figure 3A shows a schematic perspective view of an example of a monolithic, rectangular magnetic core 46 with an axial length = L (in the direction of the Z-axis) and four rounded corners 48, 48', etc., according to the present disclosure. The interior of the magnetic core 46 defines an axial bore 50.

[0031] Fig. Figure 3B shows a schematic perspective view of an example of a monolithic, rectangular magnetic core assembly 52 with an axial length = L (in the direction of the Z-axis), with four rounded corners 48, 48', etc., and three parallel electrical coaxial cables 54, 54', 54", which are arranged within and pass through the axial bore 50 of the magnetic core 46, according to the present disclosure. The remaining unused open space 23, which is located between the electrical coaxial cables 54, 54', and 54", may in some embodiments be filled with a dielectric material.

[0032] Fig. Figure 4A shows a schematic perspective cross-sectional view of an example of a rectangular AC choke 56 with an axial length = L (in the direction of the Z-axis), with four rounded corners 57, 57', etc., according to the present disclosure. The choke 56 has a hollow magnetic core 58 made of a magnetic material (e.g., iron-based ferrite material or iron-based nanocrystalline amorphous ribbon material) which defines a rectangular axial bore 72 in the interior of the magnetic core 58. Outwardly, the next layer has a first layer of a thermally conductive material 60 (e.g., thermal paste). Outwardly, the next layer has a dielectric separator 62 made of a dielectric material (e.g., polyamide, polyphenylene sulfide, epoxy resin, and / or polycarbonate, etc.). On the outside, the next layer has a metal casing 66 (e.g. an aluminum or steel alloy or a combination thereof).The next layer has a third layer made of a thermally conductive material 68 (e.g., thermal paste) on the outer side. Finally, the outermost layer of the choke 56 has a dielectric outer sheath 70 made of an insulating material (e.g., polyamide, polyphenylene sulfide, epoxy resin and / or polycarbonate, etc.).

[0033] As in Fig. As shown in Figure 4A, in some embodiments the third layer of thermally conductive material 68 (e.g., thermal paste) and the dielectric outer sheath 70 can optionally be omitted. In this embodiment, the metal housing 66 is the outermost layer.

[0034] Fig. Figure 4B shows a schematic perspective cross-sectional view of an example of a rectangular AC choke assembly 76 with an axial length = L (in the direction of the Z-axis), with four rounded corners 57, 57', etc., and three parallel electrical coaxial cables 74, 74', and 74", which are arranged in and pass through the inner axial bore 72 of the choke 56, according to the present disclosure. The remaining unused open space 25 between the electrical coaxial cables 74, 74', and 74" may, in some embodiments, be filled with a dielectric material.

[0035] Fig. Figure 5A shows a schematic perspective cross-sectional view of an example of a circular AC choke 78 with an axial length = L (in the direction of the Z-axis), according to the present disclosure. The choke 78 has a hollow, circular magnetic core 80 made of a magnetic material (e.g., iron-based ferrite material or amorphous strip material on a nanocrystalline iron base) defining a circular axial bore 94 located inside the magnetic core 80. Outwardly, the next layer has a first layer of a thermally conductive material 82 (e.g., thermal paste). Outwardly, the next layer has a circular dielectric separator 84 made of a dielectric material (e.g., polyamide, polyphenylene sulfide, epoxy resin and / or polycarbonate, etc.). Outwardly, the next layer has a second layer of a thermally conductive material 86 (e.g.,The first layer consists of thermally conductive paste). The next layer has a circular metal casing 88 (e.g., an aluminum or steel alloy or a combination thereof). The third layer has a thermally conductive material 90 (e.g., thermal paste). Finally, the outermost layer of the choke 78 has a circular dielectric outer sheath 92 made of an insulating material (e.g., polyamide, polyphenylene sulfide, epoxy resin and / or polycarbonate, etc.).

[0036] As in Fig. As shown in Figure 5A, in some embodiments the third layer of thermally conductive material 90 (e.g., thermal paste) and the dielectric outer sheath 92 can be omitted. In this embodiment, the metal housing 88 is the outermost layer.

[0037] Fig. Figure 5B shows a schematic perspective cross-sectional view of an example of a circular AC choke assembly 96 with three parallel electrical coaxial cables 98, 98' and 98", which are arranged within and pass through the inner bore 94 of the choke 78, according to the present disclosure. The remaining unused open space 27 between the electrical coaxial cables 98, 98' and 98" may, in some embodiments, be filled with a dielectric material.

[0038] Fig. Figure 6A shows a schematic perspective cross-sectional view of an example of a triangular AC choke 99 with an axial length = L (in the direction of the Z-axis), according to the present disclosure. The choke 99 has a hollow triangular magnetic core 100 made of a magnetic material (e.g., iron-based ferrite material or amorphous strip material on a nanocrystalline iron base) defining a triangular axial bore 114 located inside the magnetic core 100. Outwardly, the next layer has a first layer of a thermally conductive material 102 (e.g., thermal paste). Outwardly, the next layer has a triangular dielectric separator 104 made of a dielectric material (e.g., a polyamide, polyphenylene sulfide, an epoxy resin, and / or a polycarbonate, etc.). On the outside, the next layer has a triangular metal housing 108 (e.g.an aluminum or steel alloy or a combination thereof). Towards the outside, the next layer has a third layer of a thermally conductive material 110 (e.g., thermal paste). Finally, the outermost layer of the choke 99 has a triangular dielectric outer sheath 112 made of an insulating material (e.g., polyamide, polyphenylene sulfide, epoxy resin and / or polycarbonate, etc.).

[0039] As in Fig. As shown in Figure 6A, in some embodiments the third layer of thermally conductive material 110 (e.g., thermal paste) and the dielectric outer sheath 112 can optionally be omitted. In this embodiment, the triangular metal housing 108 is the outermost layer.

[0040] Fig. Figure 6B shows a schematic perspective cross-sectional view of an example of a triangular AC choke assembly 116 with three parallel electrical coaxial cables 118, 118', 118", which are arranged inside and pass through the axial inner bore 114 of the choke 100, according to the present disclosure.

[0041] Fig. Figure 7 shows a schematic top view of an example of an AC choke assembly 120, comprising an AC choke 130 with three parallel electrical coaxial cables 122, 122' and 122" arranged inside the choke 130 and extending through it in the direction of the Z-axis, according to the present disclosure. In this embodiment, the dielectric outer sheath 124, 124', 124" of the electrical coaxial cables 122, 122' and 122" has been removed to expose the cut conductive coaxial shield ends 126, 126' and 126" respectively. The AC choke 130 can have a rectangular, round, or triangular cross-section, as previously shown. In this embodiment, the optional dielectric outer cover 132 surrounding the AC choke 130 is shown as a dashed line, indicating that the dielectric outer cover 132 is not a required feature.In this embodiment, the AC choke 130 is located in a central section along the Z-axis of the three electrical coaxial cables 122, 122', and 122". A metal housing 170 is located inside the AC choke 130. Cut conductive coaxial shield ends 126, 126', and 126" can be connected to the top (or bottom) of the metal housing 170. The cut conductive coaxial shield ends 126, 126', and 126" are discontinuously connected to the AC choke 130.

[0042] Fig. 8A shows a schematic lateral cross-sectional view (section AA) of the in Fig. Figure 7 shows an example of an AC choke assembly 120, which comprises an electrical coaxial cable 122 that, according to the present disclosure, is electrically and mechanically integrated with an AC choke 130 having an axial length L (in the direction of the Z-axis). The electrical coaxial cable 122 has an axial central conductor 164 surrounded by a coaxial dielectric insulator 172, which in turn is surrounded by a conductive coaxial shield 128 covered by a dielectric coaxial jacket 124. In this embodiment, a short central portion (longer than the axial length L) of the dielectric coaxial jacket 124 is cut off and removed.Then, the left and right ends 129 and 129' of the conductive coaxial shield 128 in the middle section of the coaxial cable 122 are cut, and each of the cut left and right shield ends 129 and 129' is disconnected from the coaxial dielectric insulator 172 while remaining connected to the coaxial shield 128. The cut shield ends 129 and 129' can then be electrically connected to the top (or bottom) of the left and right sides of the metal housing 170, respectively. The cut shield ends 129 and 129' can be connected to the metal housing 170 by soldering, screwing, laser welding, or by crimp connections (which can be both soldered and crimped). The coaxial dielectric insulator 172 can extend continuously through the AC choke 130. Optionally, a sleeve (not shown) can be used to connect the cut shield ends 129 and 129' to the metal housing 170.

[0043] Fig. Figure 8B shows a schematic lateral cross-sectional view (section AA) of the in Fig. Figure 7 shows an example of an AC choke assembly 120, which comprises an electrical coaxial cable 122 that, according to the present disclosure, is electrically and mechanically integrated with an AC choke 130 having an axial length L (in the direction of the Z-axis). The electrical coaxial cable 122 has an axial central conductor 164 surrounded by a coaxial dielectric insulator 172, which is surrounded by a conductive coaxial shield 128, which is covered by a dielectric coaxial sheath 124. In this embodiment, a short central section (longer than the axial length L) of the dielectric coaxial sheath 124 is cut and removed.Then, the left and right ends 129 and 129' of the conductive coaxial shield 128 are cut in the middle section of the coaxial cable 122, and each of the cut shield ends 129 and 129' is disconnected from the coaxial dielectric insulator 172 while remaining connected to the coaxial shield 128. The cut shield ends 129 and 129' can then be electrically connected between the left and right sides of the metal housing 170 and the dielectric separator 166, respectively. The coaxial dielectric insulator 172 can extend continuously through the AC choke 130. The cut shield ends 129 and 129' can be connected to the metal housing 170 by soldering, screwing, laser welding, or by crimp connections (which can be both soldered and crimped). Optionally, a sleeve (not shown) can be used to connect the cut-off shield ends 129 and 129' to the metal housing 170.

[0044] Fig. Figure 9A shows a schematic top view of an example of an AC choke assembly 160, comprising an AC choke 142 attached either to a traction drive unit (TDU) 144 or to a traction power inverter module (TPIM) 144, wherein three parallel electrical coaxial cables 136, 136' and 136" are arranged inside the AC choke 142 and extend through it in the direction of the Z-axis, as described in the present disclosure. A short end of the dielectric coaxial sheath 124 is cut off and removed. Then the ends of the conductive coaxial shields 138, 138' and 138" of the electrical coaxial cables 136, 136' and 136" respectively are exposed by peeling off the dielectric coaxial sheath 124 at the entry into the right side of the choke 142. The exposed ends of the coaxial Shields 138, 138' and 138" can then be connected to the top (or bottom) of the metal housing 142.Note: The inner magnetic core 135 is shown as a dashed, hidden line.

[0045] Fig. Figure 9B shows a schematic top view of an example of an AC choke assembly 160, comprising an AC choke 142 attached either to a traction drive unit (TDU) 144 or to a traction power inverter module (TPIM) 144, wherein three parallel electrical coaxial cables 136, 136' and 136" are arranged inside the AC choke 142 and extend through it in the direction of the Z-axis, as described in the present disclosure. A short end of the dielectric coaxial sheath 124 is cut off and removed. Then the conductive coaxial shield ends 138, 138' and 138" of the electrical coaxial cables 136, 136' and 136" respectively are exposed by peeling back the dielectric coaxial sheath 124 at the entry into the right side of the choke 142. Three coaxial shield grounding sleeves 134, 134' and 134" are then connected to the exposed coaxial shielding ends 138, 138' and 138" respectively (e.g. crimped and / or soldered).The coaxial shielding grounding sleeves 134, 134' and 134" are also connected to the right side of the metal housing 142. Note: The inner magnetic core 135 is shown as a dashed, hidden line.

[0046] Fig. Figure 10 shows a schematic lateral cross-sectional view (section BB) of the in Fig. Figure 9A shows an example of an AC choke assembly 160 comprising an electrical coaxial cable 136 that is electrically and mechanically integrated with an AC choke 142, which, according to the present disclosure, is attached to a TPIM or TDU power unit 144. In this embodiment, the conductive coaxial shield end 138 of the electrical coaxial cable 136 is exposed by removing the left end of the dielectric coaxial jacket 124 as it enters the right side of the choke 142. A short end of the conductive coaxial shield 138 is stripped from the coaxial dielectric insulator 145 and electrically connected to the top (or bottom) of the right side of the metal housing 170. The cut-off end of the shield 138 can be connected to the metal housing 170 by soldering, screws, or by crimp connections (which may be both soldered and crimped).The metal housing 170 of the choke 142 is attached to the TPIM or TDU unit 144, and the axial central conductor 140 penetrates the right side of the TPIM or TDU unit 144 to establish electrical contact with it. The coaxial dielectric insulator 145 can run continuously through the AC choke 130.

[0047] Fig. Figure 11A shows a schematic top view of an example of an AC choke 148, which, according to the present disclosure, is housed in a sheet metal casing 146. The casing 146 has a pair of parallel sheet metal plates 152 and 154 that surround and securely hold the choke 148. The casing 146 further has three projections 149, 149' and 149" each having central holes 150, 150' and 150" for screwing the casing assembly 146 to a base (not shown).

[0048] Fig. Figure 11B shows a schematic top view of an example of an AC choke 148, which, according to the present disclosure, is housed in a sheet metal casing 146. The casing 146 has a pair of parallel sheet metal plates 152 and 154 that surround and securely hold the choke 148. The casing 146 further has three projections 149, 149' and 149" each having central holes 150, 150' and 150" for screwing the casing assembly 146 to a base (not shown).

[0049] Fig. Figure 11C shows a schematic front view of an example of an AC choke 148, which, according to the present disclosure, is housed in a sheet metal casing 146. The casing 146 has a pair of parallel sheet metal plates 152 and 154 that surround and securely hold the choke 148. The casing 146 further has projections 149 and 149" that have central holes 150 and 150" respectively for screwing the casing assembly 146 to a base (not shown).

[0050] Fig. Figure 11D shows a schematic side view of an example of an AC choke 148, which, according to the present disclosure, is housed in a sheet metal casing 146. The casing 146 has a pair of parallel sheet metal plates 152 and 154 that surround and securely hold the choke 148. The casing 146 further has two projections 149', 149" each having central holes 150 and 150', respectively, for screwing the casing assembly 146 to a base (not shown).

[0051] Fig. Figure 12 shows a schematic front view of an example of a magnetic core 156 of an AC choke 180 according to the present disclosure. In this embodiment, the magnetic core 156 has a plurality of thin, nanocrystalline ribbons wound in a rounded, rectangular geometry, defining an axial bore 182 located inside the core 156. The peeled coaxial shielding strip 158 is electrically connected to the upper (or lower) surface of the magnetic core 156. Optionally, a sleeve (not shown) can be used to connect the peeled coaxial shielding strip 158 to the magnetic core 156. In some embodiments, no metal housing is used, and the conductive coaxial shielding strip 158 is electrically connected to the magnetic core 156 of the AC choke 180.

[0052] Fig. Figure 13 shows a schematic perspective view of an example of a rounded triangular magnetic core 192 according to the present disclosure. In this embodiment, the rounded triangular magnetic core 192 has three rounded corners 193, 193' and 193" and an axial bore 194 arranged within the magnetic core 192 and having an axial length L aligned with the Z-axis.

[0053] Fig. Figure 14 shows a schematic perspective view of an example of a vehicle 1 with an AC choke assembly 160 according to the present disclosure. The vehicle 1 has a vehicle body 2 with four wheels 3, 3', etc., and an AC choke assembly 160 connected to a traction drive unit (TDU) or a traction power inverter module (TPIM) 144, which is connected to a traction motor (not shown).

[0054] In some embodiments, the exposed surfaces of the AC choke are covered with a dielectric insulating material.

[0055] The detailed description and the drawings or figures are supporting and descriptive of the present teaching, but the scope of the present teaching is defined exclusively by the claims. While some of the best modes and other embodiments for carrying out the present teaching have been described in detail, there are various alternative designs and embodiments for carrying out the present teaching, which are defined in the appended claims. All embodiments and examples disclosed herein are non-limiting embodiments and non-limiting examples. The words "a," "an," "the," "at least one," and "one or more" are used interchangeably to indicate that at least one of the elements is present.

Claims

[1] AC choke for reducing common-mode and bearing currents in AC drive systems, comprising: a magnetic core that defines an axial bore; a dielectric separator surrounding the magnetic core; and a metal housing that surrounds the dielectric separator; and the dielectric separator electrically isolates the magnetic core from the metal housing. [2] AC choke according to claim 1, further comprising: a first layer of a thermal interface material, arranged between the magnetic core and the dielectric separator; and a second layer of thermal interface material, positioned between the dielectric separator and the metal housing. [3] AC choke according to claim 2, further comprising: a dielectric outer sheath surrounding the metal casing; and a third layer of thermal interface material, which is positioned between the metal casing and the dielectric outer sheath. [4] AC choke according to claim 1, wherein exposed surfaces of the AC choke are covered with a dielectric insulating material. [5] AC choke according to claim 1, wherein the magnetic core comprises an iron-containing material selected from the group consisting of a nanocrystalline iron-containing material, a ferrite material and / or a combination thereof; wherein the dielectric separator comprises polyphenylene sulfide; and wherein the metal housing is made of an aluminum alloy and / or a steel alloy and / or a combination thereof. [6] AC choke according to claim 3, wherein the dielectric outer sheath comprises polyphenylene sulfide. [7] AC choke according to claim 1, wherein the magnetic core has a rectangular, rounded rectangular, circular, triangular or rounded triangular shape. [8] AC choke according to claim 1, further comprising at least one electrical coaxial cable arranged within and passing through the bore of the magnetic core. [9] AC choke assembly for reducing common-mode and bearing currents in AC drive systems, comprising: (a) an AC choke, comprising: a magnetic core that defines an axial bore; a dielectric separator surrounding the magnetic core; and a metal housing that surrounds the dielectric separator; wherein the dielectric separator electrically insulates the magnetic core from the metal casing; and the AC throttle assembly further comprises: (b) at least one electrical coaxial cable arranged within and passing through the bore of the magnetic core; and which includes at least one electrical coaxial cable: (1) an axial central conductor; (2) a coaxial dielectric insulator surrounding the axial central conductor; (3) a conductive coaxial shield surrounding the coaxial dielectric insulator; and (4) a dielectric coaxial sheath surrounding the conductive coaxial shield. [10] Vehicle, comprising: a vehicle body; one or more wheels connected to the vehicle body; and an alternating current (AC) choke assembly connected to the vehicle body; the AC throttle assembly features: (a) an AC choke, comprising: a magnetic core; an axial bore defined by the magnetic core; a dielectric separator surrounding the magnetic core; and a metal housing that surrounds the dielectric separator; (b) at least one electrical coaxial cable arranged within and passing through the bore of the magnetic core; and (c) a traction drive unit (TDU) or a traction power inverter module (TPIM) connected to the AC throttle; wherein the dielectric separator electrically insulates the magnetic core from the metal housing; which includes at least one electrical coaxial cable: (1) an axial central conductor; (2) a coaxial dielectric insulator surrounding the axial central conductor; (3) a conductive coaxial shield surrounding the coaxial dielectric insulator; (4) a dielectric coaxial sheath surrounding the conductive coaxial shield; wherein the axial central conductor is connected to the TDU or the TPIM; and the conductive coaxial shield is connected to the metal housing.

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