Power electronic circuit arrangement and method for arranging current measuring resistor in such circuit arrangement

Abstract

The invention relates to a power electronic circuit arrangement (10), comprising a plate-shaped circuit carrier (12) having an electrically insulating substrate (14) and having a conductor path arrangement (16) on a flat side (15) of the substrate (14) and having one or more power electronic components (18); a busbar (20) for conducting a current from or to a conductor path of a conductor path arrangement (16) of the circuit carrier (12); and a current measuring resistor (22), via which the busbar (20) and the associated conductor path are electrically connected to each other in order to enable a current to be measured by tapping off a measuring voltage falling at the current measuring resistor (22). In order to achieve a good electrical and thermal connection of the current measuring resistor (22) with a simultaneous cost-effective construction and connection technique, according to the invention the busbar (20) has a surface section (26) which is oriented at a vertical distance (d) from and substantially parallel to the flat side (24) of the conductor path arrangement (16), and the current measuring resistor (22) is connected between the surface section of the busbar (20) and the surface section (28) of the relevant conductor path of the conductor path device (16) and is physically and electrically connected with the surface sections (26, 28). The invention further relates to a method for arranging a current measuring resistor (22) in a power electronic circuit arrangement (10).

Description

Technical Field

[0001] The invention relates to a power electronic circuit arrangement according to the preamble of claim 1 and to a method for arranging a current measuring resistor in such a circuit arrangement. Background Art

[0002] This circuit arrangement has:

[0003] a plate-shaped circuit carrier having an electrically insulating substrate and having a conductor track arrangement on the flat side of the substrate and having one or more power electronic components which are electrically contacted by means of the conductor track arrangement,

[0004] - a busbar for conducting current from or to a conductor track of a conductor track arrangement of a circuit carrier, and

[0005] A current measuring resistor (“shunt”) via which the busbar and the associated conductor track are electrically connected to one another in order to enable the current to be measured by tapping off the measurement voltage dropped across the current measuring resistor.

[0006] Such circuit arrangements are known from the prior art in various embodiments. For this purpose, mention should be made, merely by way of example, of inverters for clocked energization of electric machines, such as electric motors in electric or hybrid vehicles.

[0007] In practice, the following requirements are usually placed on such circuit arrangements: low-inductance and low-resistance electrical connection of the current measuring resistor, low thermal resistance between the current measuring resistor and the environment or between the current measuring resistor and the cooler, small installation space, cost-effective construction and connection technology (AVT).

[0008] In particular, there is still a need for improvement in the prior art with regard to meeting the above-mentioned requirements. In the concepts known from the prior art for constructing or producing circuit arrangements of this type, there are often difficult to resolve conflicts of objectives.

[0009] According to known solutions, for example, a busbar (often also called a "busbar") is provided, which has a first section and a second section, wherein the first section runs straight and parallel to the circuit carrier at a vertical distance from the conductor track, while the second section continues with a curvature to the vertical level of the conductor track, wherein a gap is provided between the two sections, in which a current measuring resistor is arranged and is soldered to the above-mentioned section of the busbar on both sides. A disadvantage in this case is, for example, the often insufficient heat dissipation from the current measuring resistor to the environment or to a heat sink. Summary of the invention

[0010] The object of the present invention is to eliminate or at least alleviate the above-mentioned problems in a power electronic circuit arrangement of the type mentioned at the outset and therefore in particular to provide a circuit arrangement which enables good electrical and thermal connection of a current measuring resistor with simultaneously cost-effective construction and connection technology.

[0011] According to a first aspect of the invention, this object is achieved by a circuit arrangement according to claim 1. The dependent claims relate to advantageous embodiments of the invention.

[0012] The power electronic circuit device according to the invention is characterized in that

[0013] the busbar has a surface section which is at a perpendicular distance from the flat side of the conductor track arrangement and is oriented substantially parallel to the flat side, and

[0014] The current measuring resistor is interposed between the above-mentioned surface section of the busbar and the surface section of the associated conductor track of the conductor track arrangement and is physically and electrically connected or in contact with the surface section.

[0015] Advantageously, a good electrical and thermal connection of the current measuring resistor can thereby be achieved while taking up a small installation space and using cost-effective construction and connection technology.

[0016] The term "power electronic" is to be interpreted broadly and, in the context of the present invention, is to mean relatively high electrical powers for electronic devices, which are generated or controlled by the circuit arrangement, for example, during operation of the circuit arrangement. This is often the case, for example, if the circuit arrangement is designed to generate and / or control electrical energy not for pure data processing, but rather the energy is used to supply "electrical consumers". In this case, electrical consumers are primarily considered, whose power requirements can assume values ​​of more than 100 W, in particular more than 1 kW.

[0017] In this regard, in the context of the present invention, the term "bus" (English: "Busbar") can also be understood as a current flowing through the bus during operation being provided for the purpose of transmitting electrical energy in a manner other than for pure data transmission, wherein, for example, in particular during operation of the circuit arrangement, those application cases in which the electrical power transmitted via the bus reaches values ​​exceeding 100 W, in particular exceeding 1 kW.

[0018] In the context of the present invention, the term “vertical” should denote in a general manner a direction of a plate-shaped circuit carrier “orthogonal to the plate plane”.

[0019] In one embodiment of the invention, the busbars of the circuit arrangement are provided for conducting a current from or to the conductor tracks during operation of the circuit arrangement (whether direct current or alternating current), the current intensity of which can assume values ​​exceeding 100 A, in particular exceeding 250 A.

[0020] In a use of the circuit arrangement according to the invention that is of particular interest within the scope of the invention, the current intensity is at least 500 A. A specific example of this is the use or design of the circuit arrangement as an inverter (or part of an inverter) for clocked energization of electrical machines, in particular electric motors, for example in electric vehicles or hybrid vehicles.

[0021] In this application, the busbar can be an electrical line connection or at least a section of such a line connection, via which the phase currents of a multi-phase electric machine are conducted.

[0022] In one embodiment, the busbar is designed as a profile made of a metallic material, in particular copper or a copper alloy (such as so-called technical copper). This advantageously takes into account the fact that the preferred use of the circuit arrangement within the scope of the invention requires a relatively high current intensity of the current flowing through the busbar.

[0023] In one embodiment, it is provided that the cross section of the busbar (eg profile) has a width of at least 20 mm. 2 or at least 50mm 2 area.

[0024] In one embodiment, it is provided that the cross section of the busbar has an at least approximately rectangular or square shape. Alternatively, the cross section can be, for example, in particular U-shaped or L-shaped.

[0025] In one embodiment, the vertical distance between the surface section of the busbar and the flat side of the conductor track arrangement is at least 0.5 mm, in particular 1 mm, and / or at most 10 mm, in particular at most 5 mm. This design advantageously contributes to a compact arrangement with a small installation space requirement.

[0026] In one specific embodiment, it is provided that the current measuring resistor (which may also be referred to in the industry as a “shunt” in view of its function) is embodied in a laminar manner, in particular with a uniform cross section viewed in the vertical direction.

[0027] The term "lamellar Here, “the current measuring resistor has a lateral extension, i.e. an extension parallel to the plane of the circuit carrier (and perpendicular to the direction of current flow in the current measuring resistor), which is greater than its vertical extension (“lamina height”), i.e. an extension perpendicular to the plane of the circuit carrier (and parallel to the direction of current flow in the current measuring resistor).

[0028] The lateral dimension (or for example the smallest lateral dimension) of the laminar shape can in this case be, for example, at least 1.5 times, in particular at least 2 times, its vertical extension (height). Such dimensioning can advantageously contribute to a low structural height of the current measuring resistor and a good electrical and thermal connection.

[0029] The cross section of the current measuring resistor, for example a sheet-like current measuring resistor, can have, for example, a polygonal shape, such as, in particular, a rectangle or a square. Alternatively, the shape of the cross section can also be, for example, round, in particular circular. In the case of a uniform cross section viewed in the vertical direction, the current measuring resistor is then, for example, square or cylindrical.

[0030] As for the material of the current measuring resistor, in this case, for example, materials known per se from the prior art for this purpose can be advantageously used. For example, materials commercially available under the trade names "Manganin", "Konstantan" and "Zeranin" or materials similar in properties should be mentioned.

[0031] In this case, it is a special "resistance material" (for example a metal alloy) which has a low specific resistance which is only slightly temperature-dependent. It is thus advantageously achieved that the voltage drop measured at the current measuring resistor for the purpose of current measurement, i.e. the measurement voltage, is in any case slightly influenced by possible temperature fluctuations of the current measuring resistor.

[0032] Such temperature fluctuations of the current measuring resistor can be caused, for example, by fluctuations in the ambient temperature, in particular in mobile applications (e.g. power electronics in vehicles, such as inverters). In addition, the current flowing through the current measuring resistor generates heat loss, which in the case of a current that is not constant over time leads to corresponding temperature fluctuations in the current measuring resistor. Within the scope of the present invention, the latter effect is advantageously reduced by a low thermal resistance between the current measuring resistor and its environment.

[0033] The tapping of the measurement voltage dropped at the current measuring resistor or the tapping of the measurement potential required for this purpose can advantageously be achieved, for example, by means of bonding wires, which are each bonded with one end to a busbar or a conductor track in the vicinity of the current measuring resistor, wherein the respective other end of the bonding wire can in particular be bonded to a conductor track of another circuit carrier carrying the corresponding evaluation electronics (i.e. separate from the circuit carrier carrying the power electronics).

[0034] In one embodiment, it is provided that the vertical ends of the current measuring resistor located on the busbar side and / or the vertical ends located on the conductor track side are provided with a single-layer or multi-layer connecting layer.

[0035] The advantage of such a connecting layer made of a material different from the "core material" (resistance material) of the current measuring resistor is that the mechanical and thus also the electrical and thermal connection of the relevant vertical end of the current measuring resistor on the relevant surface section (busbar or relevant conductor track) can be improved. The material of each connecting layer or, in the case of a multilayer connecting layer, the material of the individual layers can be selected in an adapted or optimized manner for the specific application, i.e. according to the following:

[0036] - which materials can be connected to one another via the connecting layer (e.g. the copper alloy of the busbar and the resistance material of the current measuring resistor, and also the copper alloy of the associated conductor track and the resistance material of the current measuring resistor), and

[0037] - How these materials should be connected (connection technology).

[0038] In a related embodiment, it is provided, for example, that the connection of the current measuring resistor on the busbar side and / or on the relevant conductor track side is achieved by welding the relevant vertical end of the current measuring resistor to the relevant surface section. In this case, the weldability or the quality of the weld can be improved by a correspondingly selected connecting layer, if necessary. The connection of the current measuring resistor on the busbar side and / or on the conductor track side can also be achieved, for example, by means of welding. Another possibility for achieving such a connection is to use bonding (using a conductive adhesive). Even in the latter case, the weldability or bondability can be improved by providing a correspondingly selected corresponding connecting layer, if necessary.

[0039] In one specific embodiment, it is provided that the connection of the current measuring resistor on the busbar side and / or on the conductor track side is effected using a sintered layer between the respective vertical end of the current measuring resistor and the respective surface section.

[0040] In a special embodiment which is advantageous in many cases of application, it is provided that

[0041] the current measuring resistor is connected on the busbar side by welding, in particular ultrasonic welding, the relevant vertical end of the current measuring resistor to a surface section of the busbar, wherein a correspondingly selected connecting layer can be provided at this end if necessary to improve the weldability, and

[0042] The electrical connection of the current measuring resistor on the conductor track side is achieved by means of a sintered layer between the relevant vertical end of the current measuring resistor and a surface section of the conductor track.

[0043] According to a further aspect of the invention, the object mentioned at the outset is achieved by a method according to claim 9. The method for arranging a current measuring resistor in a power electronic circuit arrangement comprises the following steps:

[0044] a) providing a plate-shaped circuit carrier having an electrically insulating substrate and having a conductor track arrangement on a flat side of the substrate,

[0045] b) providing one or more power electronic components and making electrical contact with the power electronic components by means of the conductor track arrangement,

[0046] c) providing and arranging a busbar which is provided for conducting current from or to the conductor tracks of the conductor track arrangement in such a way that the busbar has a surface section which is at a perpendicular distance from a flat side of the conductor track arrangement and is oriented substantially parallel to the flat side,

[0047] d) providing a current measuring resistor and electrically connecting the busbar and the relevant conductor tracks of the conductor track arrangement to one another via the current measuring resistor, including connecting a surface section of the busbar to a first vertical end of the current measuring resistor and connecting a second vertical end of the current measuring resistor, which is opposite to the first vertical end of the current measuring resistor, to a surface section of the relevant conductor track of the conductor track arrangement.

[0048] With regard to the implementation of step d), it should be noted that various variants are possible for this purpose.

[0049] For example, according to a first variant, provision can be made for the busbar to be connected to the relevant, ie first, vertical end of the current measuring resistor even before the busbar is arranged relative to the circuit carrier (ie at a vertical distance from the flat side of the conductor track arrangement).

[0050] According to a second variant, it can be provided that the second vertical end of the current measuring resistor is connected to the conductor track of the conductor track arrangement even before the busbar is arranged relative to the circuit carrier. For example, this connection of the current measuring resistor to the conductor track arrangement can be carried out together with the step of electrically contacting the power electronic component or components by means of the conductor track arrangement, i.e. within the scope of equipping the circuit carrier with components.

[0051] According to a third variant, it can be provided that both the busbar and the current measuring resistor are connected to the conductor track only after the busbar has been arranged and fastened relative to the circuit carrier. In this case, the current measuring resistor can be inserted into the mounting location provided between the busbar and the conductor track and connected (for example by means of welding, soldering, etc.).

[0052] The embodiments and special configurations described here for the circuit arrangement according to the invention may also be provided in an analogous manner, alone or in any combination, as embodiments or special configurations of the method according to the invention, and vice versa.

[0053] When designing a plate-shaped circuit carrier, it is advantageously possible to use designs known per se from the prior art. For example, the circuit carrier or its electrically insulating substrate can have a rectangular format, wherein in the case of power electronic circuit arrangements, thermal requirements are often met, for example from ceramic materials, such as those based on aluminum nitride (AlN) or, for example, on aluminum oxide (AlO). 2 O 3 ) is advantageous.

[0054] If a conductor track arrangement is provided only on one of the two flat sides of the substrate, the other flat side (rear side) of the substrate can be connected to a cooler for heat dissipation purposes, for example, by being adhesively bonded to the cooler or by being soldered to the cooler via, for example, a metal layer provided on the rear side. In one embodiment, it is provided that such a cooler has cooling channels through which a cooling medium, such as cooling water, can flow during operation of the circuit arrangement.

[0055] The one or more power electronic components can be, in particular, power semiconductor components such as diodes, transistors (e.g. MOS-FETs), thyristors, etc. In particular, semiconductor components manufactured using SiC (silicon carbide) technology can be provided in this regard, for example. Furthermore, depending on the application, other components and in particular also passive components such as coils, capacitors, etc. can be electrically contacted by means of a conductor track arrangement at the flat side of the substrate.

[0056] The busbars for conducting current from or to the respective conductor tracks of the conductor track arrangement can be surrounded or encapsulated (eg extrusion-coated) at least in sections by a plastic material, for example the material of a housing or housing part of the circuit arrangement.

[0057] One or more electrical connection devices, such as plug connectors (sockets) or the like, can be provided at the housing of the circuit arrangement, via which the circuit arrangement is integrated into the relevant electrical environment. In this case, the connection device can have electrical contacts, which are electrically connected to the busbars in order to conduct the current through the housing to the busbars or from the busbars out of the housing. Depending on the implementation of the circuit arrangement, further such contacts can be provided, for example for transmitting a supply potential (supply voltage) or an electrical data signal via them.

[0058] A preferred application of the present invention is to provide a multi-phase inverter, in particular a three-phase inverter, wherein there are correspondingly multiple (for example three) busbars, via which the corresponding phase currents are output from the inverter to the relevant electrical devices (for example a three-phase drive motor).

[0059] In this case, it can be provided, for example, that the circuit arrangement has a plate-shaped circuit carrier, on which a conductor track arrangement and all components for forming an inverter are arranged, wherein a corresponding plurality (for example three) of busbars are also provided for conducting the individual phase currents from or to the respective (different) conductor tracks of the conductor track arrangement. Depending on the requirements, one or more current measuring resistors can be integrated in the manner already described in order to measure the respective phase current with each such current measuring resistor. In this case, for example, the power electronics of the inverter can advantageously be manufactured using SiC technology.

[0060] Alternatively, it can be provided, for example, that the circuit arrangement has a plurality of (for example three) plate-shaped circuit carriers, on which conductor tracks are respectively arranged and components for forming only the corresponding inverter part (for example a half-bridge for outputting a phase current), wherein in addition, a busbar is respectively arranged for conducting the relevant phase current from the relevant conductor tracks of the conductor track arrangement or for conducting the relevant phase current to the relevant conductor tracks of the conductor track arrangement. Depending on the requirements, one or more current measuring resistors can be integrated in the manner already described in order to measure the corresponding phase current with each such current measuring resistor. In this case, a plurality of circuit carriers and busbars can be accommodated in a common housing.

[0061] Furthermore, it can be provided, for example, that the circuit arrangement has a plurality of current measuring resistors. In this case, the busbar can have the same plurality of busbar branches, i.e. (end) sections of the busbar which extend from a main section of the busbar in the form of branches, tongues or arms and are formed integrally with the main section, each of which has a surface section. Similarly, the relevant conductor tracks of the conductor track arrangement can have the same plurality of surface sections. In this case, each of the current measuring resistors can be respectively inserted between a respective surface section of a respective busbar branch of the busbar and a respective surface section of the relevant conductor track, and can be physically and electrically connected or contacted with a respective surface section of a respective busbar branch of the busbar and a respective surface section of the relevant conductor track. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The present invention is further described below with reference to the accompanying drawings according to the embodiments. Schematically:

[0063] Figure 1 shows a side view of a circuit arrangement according to a first exemplary embodiment,

[0064] Figure 2 Show Figure 1 A top view of a circuit arrangement,

[0065] Figure 3 Show Figure 1 A circuit diagram of a circuit arrangement,

[0066] Figure 4 A top view of a circuit arrangement according to a second exemplary embodiment is shown, and

[0067] Figure 5 Show Figure 4 Circuit diagram of a circuit arrangement. DETAILED DESCRIPTION

[0068] Figure 1 and 2 An exemplary embodiment of a power electronic circuit arrangement 10 is shown, which has:

[0069] a plate-shaped circuit carrier 12 having an electrically insulating substrate 14 and having a conductor track arrangement 16 on a flat side 15 of the substrate 14 and having one or more power electronic components 18 which are electrically contacted by means of the conductor track arrangement 16 ;

[0070] a busbar 20 for conducting current from or to the conductor tracks of the conductor track arrangement 16 of the circuit carrier 12 ; and

[0071] A current measuring resistor (“shunt”) 22 , via which the busbar 20 and the associated conductor track are electrically connected to one another, in order to enable the current to be measured by tapping off the measurement voltage dropped across the current measuring resistor 22 .

[0072] In the example shown, it is assumed that the circuit arrangement 10 is designed as part of an inverter for clocked current supply to a three-phase electric motor in an electric vehicle or hybrid vehicle, wherein a busbar 20 of the circuit arrangement 10 is provided for conducting a pulsed current (for example a PWM phase current) during operation of the circuit arrangement 10 , the current intensity of which can assume values ​​exceeding 250 A. In this case, the busbar 20 is a section of an electrical line connection via which one of the three phase currents of the electric motor is conducted.

[0073] In this example, the electrically insulating substrate 14 consists of a ceramic material based on aluminum nitride (AlN), wherein the other flat side (back side) of the substrate 14 facing away from the device 18 is connected in a planar manner to a cooler (not shown) (for example made of aluminum or copper material) for heat dissipation purposes, for example by bonding or soldering to the cooler via, for example, a metal layer arranged on the back side.

[0074] An advantageous feature of the circuit arrangement 10 is that the busbar 20 has a surface section 26 which is at a vertical distance “d” from the flat side 24 of the conductor track arrangement 16 and is oriented parallel to the flat side 24 , and that the current measuring resistor 22 is inserted between this surface section 26 of the busbar 20 and a surface section 28 of the associated conductor track of the conductor track arrangement 16 and is connected to these surface sections 26 , 28 .

[0075] This allows for a good electrical and thermal connection of the current measuring resistor 22 with a simultaneously cost-effective design and connection technology. In this case, the current flows through the current measuring resistor 22 in a vertical direction (orthogonal to the plane of the circuit carrier 12, as a “vertical shunt”), wherein the current measuring resistor 22 is in thermal contact not only with the adjacent section of the busbar 20 but also with the conductor track arrangement and thus with the substrate 14 of the circuit carrier 12, which can usually be easily cooled, for example.

[0076] In order to ensure a sufficiently high current carrying capacity, in the example shown, the busbar 20 is constructed with a cross-sectional area of ​​approximately 40 mm 2 Profiles made of copper alloy.

[0077] In this example, the cross section is rectangular (e.g. approximately 2 mm×20 mm), wherein the surface section 26 of the busbar 20 is arranged on the long side of the rectangular cross section, which surface section is provided for connecting the current measuring resistor 22 and is oriented parallel to the flat side 24 of the conductor track arrangement 16. This advantageously enables a relatively large-area connection of the current measuring resistor 22 and furthermore contributes to a compact structural shape of the circuit arrangement 10 with a relatively low vertical installation space requirement.

[0078] In this example, the vertical distance “d” between the surface section 26 of the busbar 20 and the flat side 24 of the conductor track arrangement 16 is approximately 2 mm and likewise contributes advantageously to achieving a compact structural shape.

[0079] It is also possible within the scope of the invention that, viewed in the course of the busbar, the vertical distance changes towards the flat side of the conductor track arrangement, in particular decreases towards the end of the busbar at which the surface section is provided. This can be advantageous, for example, in connection with a specific further course of the busbar that is desired due to design.

[0080] In this example, the current measuring resistor 22 is designed in a laminar manner, ie has lateral dimensions which are more or less significantly greater than the vertical extension (height) of about 2 mm in this example. Figure 2 ), in which case the current measuring resistor 22 is square.

[0081] In this example, the current measuring resistor 22 consists predominantly (eg, more than 95% by volume, in particular more than 98%) of a metal alloy having a low specific resistance (eg, about 10 0 Up to 10 -1 Ωmm 2 / m), the specific resistance being only slightly temperature-dependent, such as the materials offered under the trade names "Manganin", "Konstantan" or "Zeranin" or materials similar in character.

[0082] This material forms to a certain extent the functional core of the current measuring resistor 22, wherein in this example the current measuring resistor 22 has not only its vertical ends on the busbar 20 side (at Figure 1 center) and at the vertical end of the relevant conductor track side (at Figure 1 The lower middle portion is provided with corresponding connection layers 30 , 32 .

[0083] In this example, each of the two connecting layers 30 , 32 , which are each designed as a single layer or multiple layers and are each made of a material different from the “core material” (resistance material), ensures a good mechanical, electrical and thermal connection of the respective vertical end of the current measuring resistor 22 on the respective surface section 30 (busbar) or 32 (conductor conductor).

[0084] The material of each connection layer 30, 32 or, in the case of a multi-layer connection layer, the material of the individual layers can be selected in an optimized manner for the specific application. In the exemplary embodiment shown, it is assumed, for example, and can be taken into account when selecting the connection layers 30, 32: a copper alloy of the busbar 22 can be connected to the resistance material (metal alloy) of the current measuring resistor 22 via the connection layer 30, and another copper alloy (of the relevant conductor track) can be connected to the resistance material of the current measuring resistor 22 via the connection layer 32.

[0085] In this example, it is provided that the connection on the busbar 20 side is effected by means of ultrasonic welding, wherein the connecting layer 30 is selected accordingly to improve the resulting welding quality, and the connecting layer 32 is a sintered layer formed in a sintering process for connecting the current measuring resistor 22 on the conductor track side.

[0086] The method for arranging the current measuring resistor 22 in the circuit arrangement 10 may include, for example, the following steps:

[0087] a) A plate-shaped circuit carrier 12 is provided, which has an electrically insulating substrate 14 and, on (at least) one flat side 15 of the substrate 14, has a conductor track arrangement 16, which can be conventionally composed, for example, of conductor tracks made of a metallic material, here for example a copper material.

[0088] b) Providing one or more power electronic components 18, such as diodes, transistors (eg bipolar or FET), thyristors, coils, capacitors etc., and electrically contacting them by means of conductor tracks 16, for example in a conventional manner by soldering component terminals to conductor tracks 16.

[0089] c) The busbar 20 is provided and arranged in such a way that it has a surface section 26 which is at a vertical distance d from the flat side 24 of the conductor track arrangement 16 and is oriented at least approximately parallel to the flat side 24 .

[0090] d) Providing a current measuring resistor 22 and electrically connecting the busbar 20 and the relevant conductor tracks of the conductor track arrangement 16 via the current measuring resistor 22 by means of:

[0091] d1) Connect the surface section 26 of the busbar 20 to the first (at the Figure 1 The vertical end connection (above) is carried out by means of welding on the connecting layer 30 in this example, and

[0092] d2) the current measuring resistor 22 is opposite to the second (at Figure 1 The lower) vertical end is connected to the respective surface section 28 of the conductor track of conductor track arrangement 16 , in this example by sintering a connecting layer 32 arranged therebetween.

[0093] The steps described above and their individual sub-steps do not necessarily have to be performed in the order described in this case. On the contrary, numerous variants are obtained for the specific order.

[0094] In the example shown, for example, a variant is provided in which the second (at the end of the second) current measuring resistor 22 is connected before the power electronics 18 is soldered to the conductor track 16 and before the busbar 20 is arranged and fastened relative to the circuit carrier 12. Figure 1 The vertical end (lower in the middle) is connected to the conductor track of the conductor track arrangement 16 via the sintered layer 32. In order to fasten the busbar 20 to Figure 1 For the purpose of the arrangement shown, the busbar can be surrounded or sheathed, for example, in sections by a plastic material of a housing or housing parts (not shown) of the circuit arrangement 10 .

[0095] To connect the second (at Figure 1 The vertical end of the lower middle Figure 1 The connecting layer 32 shown in FIG. 1 can first be arranged as a sintered blank and then sintered by suitable temperature control and thereby firmly connected to the adjacent materials, namely the material of the conductor track on the one hand and the resistor material on the other hand. As an alternative to a solid (pressed) sintered blank, it is also conceivable to use a paste containing corresponding sintering particles (e.g. a “sintering paste”) which is applied to the second vertical end of the current measuring resistor 22 and / or the surface section 28 of the conductor track arrangement 16 before the current measuring resistor 22 is arranged.

[0096] In order to measure the current of the first resistor 22 (at Figure 1 The vertical end (connecting layer 30) of the upper middle portion is ultrasonically welded, such as in Figure 1 As shown in FIG. 1 , a sonotrode 36 can be placed on the busbar 20 on its side facing away from the connecting layer 30 .

[0097] In general, in the case of the method according to the invention for arranging a current measuring resistor, before the current measuring resistor is used in the method, the current measuring resistor can already be provided with corresponding connection layers, such as connection layers 30, 32 in this example (for example metallization layers) at one or both of its ends during its production. Alternatively, at least one such connection layer can also be formed within the scope of the method according to the invention.

[0098] Figure 3 Shown in Figure 1 and 2 , which, as already mentioned, forms part of an inverter for a three-phase powered electric motor in this example. In the example shown, this is a half-bridge consisting of two MOS-FETs (devices 18) for generating phase currents, which are output via current measuring resistors 22 and busbars 20 connected thereto. During operation of the inverter, the relevant phase current of the three phase currents flows via electrical further connections (Weiterverbindung) (not shown) connected to the circuit arrangement 10 (e.g., one or more electrical plug connections, cable harnesses, etc.) to the assigned phase terminals of the electric motor. The busbar 20 is therefore a section of an electrical line connection via which the relevant phase current of the electric motor is conducted.

[0099] Since this current also flows through the current measuring resistor 22, the current intensity can be determined by tapping and evaluating the measured voltage dropped at the current measuring resistor 22. For this current measurement, Figures 1 to 3 As can be seen in , the two potentials U1 and U2 are tapped and fed to an evaluation circuit (not shown) of the circuit arrangement 10 for determining the potential difference (=tapped measurement voltage) “U2-U1” and thus the current intensity (proportional thereto).

[0100] At this point it should be noted that the evaluation circuit can optionally take into account one or more other measured variables, such as a measured variable representing the temperature of the current measuring resistor 22, when determining the current intensity. Figure 3 The control circuit of the half-bridge (power electronic component) shown in FIG. 1 can be formed on a separate circuit carrier.

[0101] As in Figure 1 and 2 As shown in FIG. 1 , the tapping of the measuring voltage U2 - U1 or the tapping of the individual measuring potentials U1 , U2 is performed by means of bonding wires. Bonding wires 38 (for U1) and 40 (for U2) enable the measurement potentials U1, U2 to be transmitted to the evaluation circuit via said bonding wires. Bonding wires 38, 40 can consist, for example, of gold, silver, copper, aluminum or corresponding metal alloys in a manner known per se.

[0102] For a current measurement that is as precise and as reproducible as possible (i.e., not too dependent on manufacturing tolerances), it is advantageous if the bonding wires 38, 40 are not each bonded directly to the material of the vertical ends of the current measuring resistor 22 (bonding points), but rather, as can be seen in the illustrated exemplary embodiment, these bonding points are each arranged on the material of an adjacent component, i.e., a conductor track (for U1) or a busbar (for U2).

[0103] For the specific arrangement of the junction point on the conductor track, it is mostly advantageous if, viewed along the conductor track, the junction point is arranged at a section of the conductor track through which no current flows, or the junction point is therefore located relative to the current measuring resistor 22 on the side of the current measuring resistor 22 that faces away from the section of the conductor track through which current flows.

[0104] The same applies to the specific arrangement of the junction point on the busbar 20. In other words, it is mostly advantageous here if, viewed along the busbar 20, the junction point is arranged at a section of the busbar 20 through which no current flows, or if the junction point is located relative to the current measuring resistor 22 on the side of the current measuring resistor 22 that faces away from the section of the busbar 20 through which the current flows. Figure 1 and 2 As can be seen in FIG. 1 , in this example the busbar 20 is slightly extended beyond the region of the current measuring resistor 22 , so that the bonding wire 40 can be connected to this “protruding” (currentless) section of the busbar 20 .

[0105] To create a three-phase inverter, Figures 1 to 3 Three circuit arrangements 10 of the type shown in the figure are combined with commonly used control electronics (for example, for driving MOS-FETs according to a PWM control scheme) and, if applicable, the evaluation circuit mentioned. In this case, the inverter comprises three plate-shaped circuit carriers 10, on which are respectively provided conductor tracks 16 and components 18 for forming only one respective inverter part (for outputting a half-bridge of a phase current) and in addition only one busbar 20 for conducting the relevant phase current.

[0106] Depending on requirements, one or more current measuring resistors 22 can be integrated into such an inverter in the manner already described in order to measure the corresponding phase current with each such current measuring resistor 22. In this case, a plurality of circuit carriers 12 and busbars 22 can be accommodated in a common housing.

[0107] In the following description of another embodiment, the same reference numerals are used for components having the same function. Here, essentially only the differences from the embodiment already described are discussed, and reference is hereby made in detail to the above description of the previous embodiment.

[0108] Figure 4 and 5 Show according to Figure 2 and 3 Another exemplary embodiment of a power electronic circuit arrangement 10 a is shown in the figure.

[0109] and Figures 1 to 3 Unlike the embodiment of the present invention, the bus 20a of the circuit arrangement 10a according to this other example has branches into multiple bus branches (two bus branches in the example), so that the bus 20a has corresponding surface sections 26a-1, 26a-2 at the ends of these bus branches, which are respectively at a vertical distance from the flat side 24a of the conductor track arrangement 16a and are oriented parallel to the flat side 24a.

[0110] Furthermore, the circuit arrangement 10a has two current measuring resistors 22a-1, 22a-2, depending on the number of busbar branches, via which the respective busbar branches of the busbar 20a are electrically connected to the respective conductor tracks of the conductor track arrangement 16a, so as to enable the current flowing through the busbar branches to be measured by tapping off (in the example two) measuring voltages U21-U11 and U22-U12 dropped at the current measuring resistors 22a-1, 22a-2.

[0111] and Figures 1 to 3 In analogy to the above-described embodiments of the present invention, in the case of the circuit arrangement 10a according to this further example, it is also provided that each of the current measuring resistors 22a-1, 22a-2 is inserted between a corresponding surface section 26a-1, 26a-2 of the relevant busbar branch of the busbar 20a and a corresponding surface section 28a-1, 28a-2 of the relevant conductor track of the conductor track arrangement 16a, and is connected to these surface sections 26a-1 or 26a-2, 28a-1 or 28a-2. These connections of the current measuring resistors 22a-1, 22a-2 can be respectively arranged in this way or can be realized within the scope of a method for arranging a plurality of (for example two) current measuring resistors in a power electronic circuit arrangement, as has already been described with reference to Figures 1 to 3 An embodiment of the invention is described.

[0112] In the case of this further embodiment, the two potential differences U21-U11 and U22-U12 or the two corresponding measuring potential pairs U11, U21 and U12, U22 can again be transmitted by means of bonding wires 38a-1, 40a-1, 38a-2, 40a-2 to an evaluation circuit of the circuit arrangement 10a, which can thereby determine the current intensity of the current flowing through the busbar 20a (as the sum of the two partial currents flowing through the individual busbar branches). In this example, the (not shown) evaluation circuit is advantageously arranged on a separate circuit carrier (less expensive than the circuit carrier 12a with a ceramic substrate 14a).

[0113] As in Figure 4 and 5 The advantages of the embodiment with branched busbars as shown in FIG. 1 are, for example, that compared with the first example ( Figures 1 to 3 ), each of the current measuring resistors 22a-1, 22a-2 is less loaded and can therefore be dimensioned smaller, for example, than would be the case if only a single current measuring resistor were used, as in FIG. 1 . In addition, due to the spatial distribution of the plurality of current measuring resistors 22a-1, 22a-2, the heat loss generated by the current measurement can generally be dissipated better.

[0114] The circuit device 10a and Figures 1 to 3 Another difference of the embodiment of is that, viewed in the direction of the busbar 20a, the vertical distance between the busbar 20a and the flat side 24a of the conductor track arrangement 16a decreases toward the end of the busbar branch. In this example, the busbar 20a has a correspondingly angled extension section in the region of the two busbar branches.

[0115] Another difference of the circuit arrangement 10a from the embodiments already described is that the cross section of each of the current measuring resistors 22a-1, 22a-2 is circular. With this cross section (consistent in the vertical direction in this example), a cylindrical shape is then obtained for each current measuring resistor 22a-1, 22a-2.

[0116] Reference numerals list

[0117] 10 Circuit Device

[0118] 12 Circuit carrier

[0119] 14 substrates

[0120] 15 Flat side of substrate

[0121] 16 Printed conductor device

[0122] 18(One or more) devices

[0123] 20 Bus

[0124] dVertical distance

[0125] 22 Current measurement resistor (shunt)

[0126] U1 measuring potential

[0127] U2 measuring potential

[0128] 24 Flat side of the printed conductor arrangement

[0129] 26 Surface section of busbar

[0130] 28 Surface section of conductor track

[0131] 30 connection layers

[0132] 32 connection layers

[0133] 36 Ultrasonic welding electrode

[0134] 38 bonding wire

[0135] 40 bonding wires.

Claims

1. A power electronic circuit device (10), include: a plate-shaped circuit carrier (12) having an electrically insulating substrate (14) and having a conductor track arrangement (16) on a flat side (15) of the substrate (14) and having one or more power electronic components (18) which are electrically contacted by means of the conductor track arrangement (16); a busbar (20) for conducting current from or to the conductor tracks of the conductor track arrangement (16) of the circuit carrier (12); and a current measuring resistor (22), via which the busbar (20) and the associated conductor track are electrically connected to one another in order to enable the current to be measured by tapping off a measurement voltage dropped at the current measuring resistor (22), characterized in that the busbar (20) has a surface section (26) which is at a vertical distance (d) from a flat side (24) of the conductor track arrangement (16) and is oriented substantially parallel to the flat side (24), and The current measuring resistor (22) is inserted between the above-mentioned surface section (26) of the busbar (20) and the associated surface section (28) of the conductor track of the conductor track arrangement (16) and is physically and electrically connected to the surface sections (26, 28).

2. The circuit arrangement (10) according to claim 1, wherein the busbar (20) is designed as a profile part made of a metallic material.

3. The circuit arrangement according to claim 1 , wherein the cross section of the busbar ( 20 ) has a width of at least 20 mm. 2 or at least 50mm 2 area.

4. A circuit arrangement (10) according to any of the preceding claims, wherein the vertical distance (d) between the surface section (26) of the busbar (20) and the flat side (24) of the conductor track arrangement (16) is at least 0.5 mm or 1 mm and at most 10 mm or at most 5 mm. 5 . The circuit arrangement ( 10 ) as claimed in claim 1 , wherein the current measuring resistor ( 22 ) is embodied in a laminar manner with a uniform cross section viewed in a vertical direction.

6. The circuit arrangement (10) according to claim 1 , wherein the vertical ends of the current measuring resistor (22) on the busbar (20) side and / or on the associated conductor track side are provided with a single-layer or multi-layer connecting layer (30, 32).

7. The circuit arrangement (10) according to claim 1 , wherein the physical and electrical connection of the current measuring resistor (22) on the busbar (20) side and / or on the relevant conductor track side is achieved by welding, sintering, soldering, riveting, screwing or gluing the relevant vertical ends of the current measuring resistor (22) to the relevant surface sections (26, 28).

8. The circuit arrangement (10) according to claim 1 , wherein the physical and electrical connection of the current measuring resistor (22) on the busbar (20) side and / or on the associated printed conductor side is realized using a sintered layer (32) between the associated vertical end of the current measuring resistor (22) and the associated surface section (26, 28).

9. The circuit arrangement (10) as claimed in any one of the preceding claims, wherein - the circuit arrangement (10) comprises a plurality of current measuring resistors (22a-1, 22a-2); - the busbar (20) has the same number of busbar branches, each of which has a surface section (26a-1, 26a-2); The respective conductor tracks have the same number of surface sections (28a-1, 28a-2); - wherein each of the current measuring resistors (22a-1, 22a-2) is respectively inserted between a corresponding surface section (26a-1, 26a-2) of a corresponding bus branch of the busbar (20a) and a corresponding surface section (28a-1, 28a-2) of the associated printed conductor, and is physically and electrically connected to a corresponding surface section (26a-1, 26a-2) of a corresponding bus branch of the busbar (20a) and a corresponding surface section (28a-1, 28a-2) of the associated printed conductor.

10. A method for arranging a current measuring resistor (22) in a power electronic circuit arrangement (10), The following steps are involved: a) providing a plate-shaped circuit carrier (12) having an electrically insulating substrate (14) and a conductor track arrangement (16) on a flat side (15) of the substrate (14), b) providing one or more power electronic components (18) and making electrical contact with the power electronic components by means of the conductor track arrangement (16), c) providing and arranging a busbar (20) which is designed to conduct current from or to the conductor tracks of the conductor track arrangement (16) such that the busbar has a surface section (26) which is at a vertical distance (d) from a flat side (24) of the conductor track arrangement (16) and is oriented substantially parallel to the flat side (24), d) providing a current measuring resistor (22) and electrically connecting the busbar (20) and the associated conductor tracks of the conductor track arrangement (16) to one another via the current measuring resistor (22), including physically and electrically connecting a surface section (26) of the busbar (20) to a first vertical end of the current measuring resistor (22), and physically and electrically connecting a second vertical end of the current measuring resistor (22) opposite to the first vertical end of the current measuring resistor (22) to a surface section (28) of the associated conductor track of the conductor track arrangement (16).

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