Power converter, device including motor and power converter, and vehicle

Abstract

This document discloses a power converter (1) comprising a housing (2) and a bus device (5) disposed in the housing (2), wherein the power converter (1) is designed to guide alternating current along the bus device (5), and the power converter (1) further comprises at least one planar flux conducting element (19, 20) made of a high permeability material, the planar flux conducting element (19, 20) being disposed between the wall (13a, 14a) of the housing (2) and the bus device (5).

Description

Technical Field

[0001] The present invention relates to a power converter comprising a housing and a bus arrangement disposed within the housing, wherein the power converter is designed to guide alternating current along the bus arrangement.

[0002] Furthermore, the present invention relates to an apparatus including a motor and a power converter, and also to a vehicle. Background Technology

[0003] In power converters, alternating current (AC) on both the input and output sides is typically guided through busbars. In this case, the busbars may radiate alternating magnetic fields during operation. According to electromagnetic compatibility guidelines such as those of ICNIRP (International Commission on Non-Ionizing Radiation Protection), the magnetic flux density outside the power converter housing must be limited to permissible values. Therefore, personnel in the environment surrounding the power converter must be protected from non-ionizing radiation. This is particularly true when power converters are used in electric vehicles, where they must be located near vehicle occupants, thus requiring adherence to limits designed to protect them. These guidelines typically include provisions for limiting alternating magnetic fields in certain frequency ranges, particularly below 1 kHz.

[0004] Various methods for confining magnetic fields are known. Therefore, the housing can be made of highly permeable materials, but this is expensive and results in a heavier power converter. Due to space constraints in vehicles, it is generally not possible to increase the distance between vehicle occupants and the power converter, or to use thick sleeves in the housing to generate significantly high eddy currents. Reducing magnetic field radiation to optimize the bus configuration's shape can also be considered, but this limits the freedom of mounting the bus configuration within the housing. It is also known to form housings from sandwich materials, such as a layer of aluminum and a ferromagnetic layer plated thereon; however, this, in turn, leads to high costs. Summary of the Invention

[0005] Therefore, the object of the present invention is to describe the possibility of improving the electromagnetic compatibility of power converters, which can be manufactured economically in terms of cost and weight of the power converter and produce low electrical losses.

[0006] To address this problem, according to the present invention, such a power converter, first described, includes at least one planar flux conduction element made of a high-permeability material, which is arranged between the wall of the housing and the bus assembly.

[0007] The present invention is based on the consideration that, in terms of the radiation of alternating magnetic fields (especially in the frequency range below 1 kHz), the electromagnetic compatibility of the power converter is improved by introducing at least one planar flux conduction element between the walls of the housing and between the bus devices, and that shielding is provided not across the entire housing, but only at specific locations in a region of the housing (where the magnetic field is radiated particularly strongly).

[0008] This planar flux-conducting element can be advantageously and economically manufactured, resulting in only a slight increase in weight, and can be precisely tailored to fit its mounting location. This also allows for the relatively late addition of the flux-conducting element within the design process of the power converter, making it flexible to adapt to changes in standards or regional differences in electromagnetic compatibility regulations. Planar flux-conducting elements also have the advantage of introducing only small electrical losses, as hysteresis and eddy current losses in the flux-conducting element are essentially dependent on the magnetic flux density within the element and the volume of the flux-conducting element. The latter is advantageously smaller due to the planar design.

[0009] The power converter is preferably configured as an inverter. The housing is typically formed of a low-permeability material, such as aluminum or an aluminum alloy. In the context of this invention, the term "low permeability" should be particularly understood to mean a permeability close to 1, particularly between 0.9 and 1.1. In the context of this invention, the term "high permeability" should be particularly understood to mean a permeability of at least 50, preferably at least 100, and particularly preferably at least 1000. The wall may form a cover or another inner side of the housing. It is generally specified that the flux-conducting element or flux-conducting element is arranged on the wall itself or in another component between the wall of the power converter and the busbar assembly.

[0010] Advantageously, the flux-conducting element is formed of a ferromagnetic or ferrimagnetic material. The flux-conducting element may be formed of a soft iron material (e.g., used in transformer constructions). The flux-conducting element typically has a thickness of up to 4 mm, preferably up to 2 mm, particularly preferably up to 1.2 mm, and / or at least 0.05 mm, preferably at least 0.1 mm, particularly preferably at least 0.5 mm.

[0011] A bus device may include one or more buses. Buses may form multiple bus groups.

[0012] In the power converter according to the invention, the flux-conducting element may be formed of a metal plate. Such a metal plate is readily available and economical. Alternatively, the flux-conducting element may be formed of a ferrite plate.

[0013] In an advantageous embodiment of the power converter according to the invention, the housing comprises a first housing element and a cover element formed of a low-permeability material, the cover element being disposed within the first housing element, wherein flux-conducting elements are arranged on the cover element between the wall formed by the first housing element and the bus arrangement. In the case of a low-permeability cover element, the localized increase in the permeability of the flux-conducting elements is particularly advantageous because only relatively small eddy currents are typically induced in the cover element, thus providing only a small shielding effect for magnetic fields in the frequency range of interest. The cover element is preferably planar and / or formed of aluminum.

[0014] Flux-conducting elements can be fixed to the cover element, for example, by bonding and / or welding and / or by fastening elements (e.g., screws or rivets). Flux-conducting elements can also be bonded to the cover element by fusion and / or rolling and / or sintering and / or electroplating.

[0015] Alternatively, the bus assembly can be led out of the first housing element through at least one opening in the second wall of the first housing element, the opening extending specifically perpendicular to the first wall, and the flux-conducting element arranged on the opening-side edge portion of the covering element. Measurements show that such an area is particularly critical for the radiation of the alternating magnetic field through the first wall in the frequency range of interest, and therefore for mounting the flux-conducting element on the opening-side edge portion, which particularly contributes to improved electromagnetic compatibility. Multiple openings can also be provided, with individual bus groups of the bus assembly being guided through each opening.

[0016] In an advantageous improvement, the covering element includes a protrusion pointing towards at least one opening, and a flux-conducting element extends over the protrusion. Since the covering element is extended to the vicinity of the second wall with the opening by means of the protrusion, the shielding effect can be greatly extended spatially. The shape of the flux-conducting element substantially corresponds to the shape of the protrusion. Preferably, the flux-conducting element does not extend in the region parallel to the gap between the protrusions.

[0017] To achieve an additional shielding effect through eddy currents induced in the cover element, the cover element preferably has a greater thickness in the portion where the flux-conducting element is arranged than in other portions. This greater thickness can be achieved by raising the cover element on the side facing or away from the busbar assembly.

[0018] Advantageously, the covering element has a recess in which a flux-conducting element is arranged. This facilitates the secure fastening of the flux-conducting element. The depth of the recess is preferably at most 1.5 times the thickness of the flux-conducting element disposed therein, and particularly preferably at most 1.1 times.

[0019] The first housing element typically houses the power electronics unit of the power converter, which is designed to receive or provide alternating current on the input side.

[0020] In the case of the power converter according to the invention, it is preferably further specified that the housing includes a second housing element having at least one opening through which a bus device is guided into the second housing element, and a flux-conducting element is arranged between a wall formed by the second housing element and the bus device, the wall extending perpendicularly to the second wall having at least one opening. Measurements have shown that the first wall of the second housing element is also a strong radiation area of ​​the power converter. Therefore, electromagnetic compatibility can also be improved in these areas by means of the flux-conducting element. Multiple openings can be provided, through which individual bus groups of the bus device are guided.

[0021] Typically, the flux conducting element previously described and arranged on the cover element may also be referred to as the first flux conducting element, and the flux conducting element arranged between the first wall of the second housing element and the busbar device may also be referred to as the second flux conducting element.

[0022] The flux-conducting element is preferably disposed on the first wall. For this purpose, the first wall advantageously has a slit into which the flux-conducting element is inserted. The flux-conducting element can be fixed to the first wall, for example, by bonding and / or welding and / or by fastening elements such as screws or rivets. Alternatively, the flux-conducting element can be bonded to the first wall, for example, by fusion and / or rolling and / or sintering and / or electroplating.

[0023] Particularly preferably, the housing elements are arranged abutting each other such that the busbar device is guided through a specific opening from the first housing element into the second housing element. Therefore, in the boundary regions between the housing elements, especially those affected by radiation from alternating magnetic fields, electromagnetic compatibility can be effectively improved by flux-conducting elements. Typically, the second walls of the first and second housing elements, i.e., each wall, have openings and are formed as multiple components and / or secured to each other by fastening elements. According to a particularly preferred embodiment, a portion of the second housing element defining at least one opening of the second housing element protrudes into at least one opening of the first housing element.

[0024] In specific embodiments of the power converter, the flux conduction element is defined as a single, integral flux conduction device that passes through an opening. The flux conduction device is typically entirely planar. All embodiments used to generate individual flux conduction elements can be adapted to the flux conduction device.

[0025] The second housing element typically houses the connection device for connecting the busbar assembly to the motor. In this respect, the second housing element can also be interpreted as, or referred to as, a terminal box, connection box, or junction box.

[0026] The objective that forms the basis of this invention is also achieved by a device comprising a motor and a power converter according to the invention, wherein the power converter is designed to provide alternating current to generate a rotating field of the motor.

[0027] The objective that forms the basis of this invention is also achieved by a vehicle that includes the device according to the invention, wherein an electric motor is designed to drive the vehicle. Attached Figure Description

[0028] Referring to the accompanying drawings, further advantages and details of the invention will become clear from the exemplary embodiments described below. These are schematic diagrams and illustrations:

[0029] Figure 1 This is a basic illustration of a first exemplary embodiment of a power converter according to the present invention;

[0030] Figure 2 This is a basic perspective view of the first exemplary embodiment;

[0031] Figure 3 This is a basic perspective view of a region of the second housing element in the first exemplary embodiment;

[0032] Figure 4 This is a detailed cross-sectional view of a second exemplary embodiment in a region of the first housing element;

[0033] Figure 5 This is a basic perspective view of a third exemplary embodiment of a power converter according to the present invention;

[0034] Figure 6 This is a basic perspective view of a fourth exemplary embodiment of a power converter according to the present invention;

[0035] Figure 7 This is a basic cross-sectional view of a fifth exemplary embodiment of a power converter according to the present invention;

[0036] Figure 8 This is a basic perspective view of a sixth exemplary embodiment of a power converter according to the present invention;

[0037] Figure 9 This is a basic perspective view of an exemplary embodiment of a vehicle according to the present invention, including the device according to the present invention. Detailed Implementation

[0038] Figure 1 A basic illustration of a first exemplary embodiment of the power converter 1 is shown.

[0039] The power converter 1 includes a housing 2 having a first housing element 3 and a second housing element 4. The housing 2 is formed of a low-permeability material, currently aluminum or an aluminum alloy, to reduce the weight of the power converter 1. The power converter 1 also includes a bus assembly 5 comprising two bus groups 6 and 7, each bus group 6 and 7 having three buses 6a, 6b, 6c and 7a, 7b, 7c, respectively. The bus assembly 5 is connected on the output side to the power electronics unit 8 of the power converter 1, configured as an inverter, wherein each bus group 6 and 7 carries three-phase alternating current. Furthermore, the power converter 1 includes a DC voltage connector 9, which is connected to the input of the power electronics unit 8 via an additional bus 10.

[0040] The power electronics unit 8, DC voltage connector 9, and bus 10 are all housed in the first housing element 3, which also houses the cover element 11 and a printed circuit board 12 disposed between the power electronics unit 8 and the cover element 11, and includes a control electronics unit for the power electronics unit 8. Conversely, the second housing element 4 forms a junction box or junction box for connecting the motor to the power converter 1. For this purpose, the second housing element 4 houses a connection device 33 (see...). Figure 9 ).

[0041] The first housing element 3 has a first wall 13a forming a cover plate of the first housing element 3 (see...). Figure 2 The second housing element 4 has a second wall 13b forming a sidewall, another sidewall, and a third wall 13c forming a bottom wall. The sidewalls extend vertically from the third wall 13c and thus form a receiving space enclosed by the first wall 13a. The second housing element 4 has a first wall 14a (see...). Figure 4 The second wall 14b, which forms a sidewall, the other sidewalls, and the third wall (not shown) opposite the first wall 14a.

[0042] Bus 5 extends from the power electronics unit 8 through two openings 15 and 16 in the second wall 13b of the first housing element 2 and through two openings 17 and 18 in the second wall 14b of the second housing element 4 into the second housing element 4. Therefore, the first bus group 6 extends through openings 15 and 17, and the second bus group 7 extends through openings 16 and 18. Inside the second housing element 4, the bus 5 extends... Figure 1 In the drawing plan.

[0043] Inside the first housing element 3, the busbar assembly 5 extends primarily between the third wall 13c and the cover element 11. A first flux-conducting element 19 is disposed on the cover element between the busbar assembly 5 and the first wall 13c. The first flux-conducting element is located on the open-side edge portion of the cover element 11. A second flux-conducting element 20 is disposed on the first wall 14a of the second housing element 4 between the wall and the busbar assembly 5. Both flux-conducting elements 19 and 20 are planar, 1 mm thick, and formed from a highly permeable metal plate made of soft iron material. They are used to shield alternating magnetic fields with frequencies up to 1 kHz to improve the electromagnetic compatibility of the power converter 1.

[0044] Figure 2 This is a basic perspective view of the power converter 1, showing the arrangement of the first flux conducting element 19 on the cover element 11, and the arrangement of the first wall 13a of the first housing element 3 in a position not connected to the side wall. The first flux conducting element 19 rests against the substantially flat cover element 11.

[0045] Figure 3 This is a basic perspective view of the power converter 1 in the region of the second housing element 4.

[0046] Once the busbar 5 has passed through openings 17 and 18, its angled profile can be seen. The second flux-conducting element 20 is positioned on the first wall 14a by placing it in a groove formed in the first wall 14a, and is then bonded or welded to the first wall.

[0047] Further exemplary embodiments of the power converter 1 will be described below, wherein similar or functionally similar components have the same reference numerals. Unless otherwise stated, the other exemplary embodiments correspond to the first exemplary embodiment.

[0048] Figure 4 This is a detailed cross-sectional view of a second exemplary embodiment of the power converter 1 in the region of the first housing element 3, wherein there is no busbar device 5 and no flux conduction element 19.

[0049] The portion 21 on which the first flux-conducting element 19 is arranged has a greater thickness than other portions of the covering element 11. Therefore, sufficiently large eddy currents can be generated in the covering element 11 to further improve the shielding effect.

[0050] A recess 22 is further formed in the portion 21 of the cover element on the side opposite to the busbar device 5, wherein a flux conducting element 19 is arranged in the recess. The recess, similar to the flux conducting element 19, is 1 mm deep, such that the edge 23 of the recess terminates flush with the flux conducting element 19.

[0051] Figure 5 This is a basic perspective view of a third exemplary embodiment of the power converter 1. In the third exemplary embodiment, the first housing element 3 has a frame-like protrusion 24 surrounding the openings 15, 16 on its second wall 13b. The cover element 11 has protrusions 25a, 25b pointing towards the openings 15, 16 and abutting against the protrusions 24, and is connected via an offset portion 26 to the portion 21 on which the first flux-conducting element is arranged. However, in the second exemplary embodiment, the portion 21 is not thickened.

[0052] Figure 6 This is a basic perspective view of a fourth exemplary embodiment of the power converter 1. In this fourth exemplary embodiment, the first housing element 3 also includes a protrusion 24. The cover element has four protrusions 25a to 25d, which protrude from the thickened portion 21 toward the openings 15 and 16 and abut against the protrusions 24. In this case, the first flux-conducting element 19 also extends above the protrusions 25a to 25d.

[0053] Figure 7 This is a basic cross-sectional view of a fifth exemplary embodiment of the power converter 1. In the fifth exemplary embodiment, the flange-like portion 27 of the second housing element 4 defines openings 17 and 18, which extend into openings 15 and 16 in the first housing element 3.

[0054] Figure 8 This is a basic cross-sectional view of a sixth exemplary embodiment of the power converter 1, wherein the first wall 13a of the first housing element 3 and the first wall 14a of the second housing element 4 are formed by an integral cover element 28.

[0055] According to the seventh exemplary embodiment (not shown), flux conduction elements 19 and 20 are formed by an integral flux conduction device through openings 15 to 18.

[0056] The aforementioned exemplary embodiments are generally composable. According to another exemplary embodiment, one or each flux-conducting element 19, 20 may be formed of a ferrite plate. In another exemplary embodiment, one or each flux-conducting element 19, 20 is provided and incorporated into the cover element 11 or the first wall 14a of the second housing element 4, for example by fusion, rolling, sintering or electroplating processes, or by fastening elements such as screws or rivets.

[0057] Figure 9This is a basic illustration of an exemplary embodiment of a vehicle 30 having an exemplary embodiment of the device 31. This includes a motor 32 designed to drive the vehicle 30 and a power converter 1 according to one of the previously described exemplary embodiments. The power converter 1 is designed to provide alternating current to generate a rotational field for the motor 32. A connection device 33 arranged in the second housing element 4 is also shown, by means of which the motor 32 is connected via a busbar device 5 to the power electronics unit 8 of the power converter 1.

Claims

1. A power converter comprising a housing (2) and a busbar assembly (5) disposed within the housing (2), wherein the power converter (1) is configured to guide alternating current along the busbar assembly (5), characterized in that, At least one planar flux guiding element (19, 20) made of a high magnetic permeability material is arranged between the wall of the housing (2) and the bus device (5). The housing includes a first housing element (3) and a second housing element (4) arranged opposite to each other, and the busbar device (5) is arranged inside the first housing element (3) and guided from the first housing element (3) into the second housing element (4); A cover element (11) made of a low magnetic permeability material is arranged inside the first housing element (3) and is located between the first wall (13a) formed by the first housing element (3) and the busbar device (5); One of the planar flux guiding elements is arranged inside the first housing element (3) and on the cover element (11), and the other planar flux guiding element is arranged inside the second housing element (4) and between the first wall (14a) formed by the second housing element (4) and the busbar device (5).

2. The power converter according to claim 1, wherein, The planar flux guiding elements (19, 20) are formed of metal plates or ferrite plates.

3. The power converter according to claim 2, wherein, The busbar device (5) is led out from the first housing element (3) through at least one opening (15, 16) in the second wall (13b) of the first housing element (3), and the planar flux guiding element is arranged on the opening-side edge portion of the cover element (11).

4. The power converter according to claim 3, wherein, The covering element (11) has a protrusion (25a-25d) pointing to at least one opening (15, 16), and the planar flux guiding element extends over the protrusion (25a-25d).

5. The power converter according to any one of claims 1-4, wherein, The covering element (11) has a greater thickness in the portion where the planar flux guiding element is arranged than in other portions.

6. The power converter according to any one of claims 1-4, wherein, The covering element (11) has a recess (22), wherein the planar flux guiding element is arranged in the recess (22).

7. The power converter according to any one of claims 1-4, wherein, The first housing element (3) houses the power electronics unit (8) of the power converter (1), which is designed to receive AC power on the input side or provide AC power on the output side.

8. The power converter according to any one of claims 1-4, wherein, The second housing element (4) has at least one opening (17, 18), through which the busbar device (5) is guided into the second housing element (4), and the first wall (14a) of the second housing element (4) extends perpendicularly to the second wall (14b) including at least one of the openings (17, 18).

9. The power converter according to claim 8, wherein, The planar flux guiding element is arranged on the first wall (14a) of the second housing element (4).

10. The power converter according to claim 8, wherein, The busbar device (5) is guided from the first housing element (3) through the opening into the second housing element (4).

11. The power converter according to claim 10, wherein, The planar flux guiding elements (19, 20) are formed by an integrated flux conduction device through the opening.

12. The power converter according to claim 9, wherein, The second housing element (4) houses a connection device (33) for connecting the busbar device (5) to the motor (32).

13. An apparatus comprising a motor (32) and a power converter according to any one of claims 1-12, wherein, The power converter (1) is designed to provide alternating current for generating the rotating field of the motor (32).

14. A vehicle comprising the device according to claim 13, wherein, The motor (32) is designed to drive the vehicle (30).

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