Power core for an inverter of an electric drive axle, and inverter having such a power core

Abstract

The invention relates to a power core (200) for an inverter (130), said power core (200) comprising a busbar assembly (305), a first lead frame (310), a second lead frame (311), a third lead frame (312) and three half-bridge packages (205). Each half-bridge package (205) has a ceramic substrate (400) with a ceramic layer (405) between a lower copper layer (410) and an upper copper layer (415); the upper copper layer (415) comprises a first segment (420) and a second segment (425) spaced apart therefrom; a plurality of first power semiconductors (500) are arranged on the first segment (425) at least in an elliptical shape; a number of second power semiconductors (505) corresponding to the first power semiconductors (500) are arranged on the second segment (425) at least in an elliptical shape; the first segment (420) is connected to the first lead frame (310) via a first load connection (430); the first power semiconductors (500) are connected to the second segment (425) via a busbar (440); the second segment (425) is connected to the second lead frame (311) via a second load connection (435); and the second power semiconductors (505) are connected to the third lead frame (312) via a third load connection (445). The invention also relates to an inverter (130), an electric drive axle (100) and a motor vehicle (105).

Description

[0001] Power core for an inverter of an electric drive axle and inverter with such a power core

[0002] The present invention relates to a power core for an inverter. Furthermore, the invention relates to an inverter for an electric drive axle having such a power core, an electric drive axle comprising an inverter, and a motor vehicle.

[0003] Purely electric vehicles and hybrid vehicles are known in the prior art. Purely electric vehicles are powered exclusively by one or more electric machines as drive units. In hybrid vehicles, one or more electric machines are used to support the combustion engine. In order to supply the electric machines of such electric vehicles or hybrid vehicles with electrical energy, such motor vehicles comprise electrical energy storage devices, in particular rechargeable electric batteries. These batteries are designed as direct voltage sources, but the electric machines generally require an alternating voltage with several, typically three, current phases. This generates a rotating electromagnetic field in the electric machine, which causes the rotor of the electric machine to rotate by induction.Therefore, a power electronics system with a so-called inverter is usually connected between the battery and the motor vehicle's electric motor. Such inverters typically comprise a power core with semiconductor switching elements or half-bridge packages that are combined to form half-bridges or each form a half-bridge.

[0004] One object of the invention is to provide a compact and flexibly designed power core for an inverter. The invention achieves this object by means of the subject matter of the independent claims. Subclaims specify preferred embodiments.

[0005] A power core according to the invention for an inverter of an electric drive axle comprises a busbar arrangement, a first leadframe, a second leadframe, and a third leadframe, as well as three half-bridge packages, each half-bridge package having a ceramic substrate with a ceramic layer between a lower copper layer and an upper copper layer, the upper copper layer comprising a first segment and a second segment spaced therefrom, a plurality of first power semiconductors being arranged at least in an elliptical shape on the first segment, a number of second power semiconductors corresponding to the first power semiconductors being arranged at least in an elliptical shape on the second segment, the first segment being connected to the first leadframe via a first load connection, the first power semiconductors being connected to the second segment via a busbar,wherein the second segment is connected to the second leadframe via a second load terminal, and wherein the second power semiconductors are connected to the third leadframe via a third load terminal.,

[0006] The power core is responsible for converting direct current (DC) from a DC source, such as an energy storage device or a rectifier, into alternating current. The power core regulates the inverter's power output to produce the desired AC voltage, frequency, and power. Depending on the application, this may mean that the inverter can adjust voltage and frequency. The power core helps ensure the stability and efficiency of the inverter. This includes minimizing losses during conversion and providing a stable AC power supply.

[0007] The respective half-bridge package is to be understood as the B2 package of the electronic power core. The respective half-bridge package forms a half-bridge of a motor control system. Several half-bridges, preferably three half-bridges, can be provided in a separately controllable manner in order to operate an electrical machine of a motor vehicle. The half-bridge package is used to switch current, in particular for consumers in the several tens of kW range, in particular for electrical machines, e.g. for a motor vehicle. It is of course conceivable to provide six half-bridge packages in the power core, with two half-bridge packages being combined to form a half-bridge. The half-bridges are preferably electrically connected in parallel. With three half-bridge packages, one half-bridge package is provided per switching position or phase. With six half-bridge packages, two half-bridge packages are provided per switching position or phase.

[0008] For each half-bridge package, three lead frames with different potentials are provided, with each lead frame having one or more load terminals for connection to components of the half-bridge package.

[0009] The leadframes are intended for the external connection of the half-bridge packages to the busbar arrangement. Depending on the design, the leadframes can be enclosed by the busbar arrangement or by the respective half-bridge package. The leadframes can be formed from a common sheet metal and formed into a stamped grid by punching and forming, and then brought into their final shape.

[0010] Similarly, load terminals can be designed to connect components of the half-bridge package to the leadframes. After punching and forming the sheet metal into the leadframe, connecting the leadframes to the ceramic substrate via the associated load terminals, and subsequent encapsulation, a remaining frame, which may be fixed during production, can be separated from the leadframes and / or load terminals to separate the load terminals and / or leadframes from each other.

[0011] The upper copper layer is arranged on top of the ceramic substrate, facing the leadframes, and is at least divided into two parts, i.e., segmented into a first half and a second half. The ceramic substrate can be an AMB (Active Metal Brazing) substrate, a DBC (Direct Copper Bonding) substrate, or a DPC (Direct Plated Copper) substrate.

[0012] The first segment of the upper copper layer forms the so-called "high side" of the power core, and the second segment of the upper copper layer forms the so-called "low side" of the power core, or vice versa. The "high side" is located on the side with the higher electrical potential reference and is connected to the high potential. The "low side" is located on the side with the lower electrical potential reference, i.e., ground or the negative supply potential, and is connected to the so-called "low potential."

[0013] The upper copper layer of the ceramic substrate can be further segmented or subdivided. This means that the upper copper layer can comprise more than two segments. Further segmentation of the upper copper layer may be necessary to electrically connect additional parts of the half-bridge package to one another, to electrically separate other parts of the half-bridge package from one another, and / or to thermally couple parts of the half-bridge package to the ceramic substrate. The thermal coupling can reduce the temperature in one or more leadframes and the busbar arrangement electrically connected thereto. The upper copper layer can be segmented by targeted etching after it has been applied to the ceramic layer.

[0014] The ceramic layer of the respective ceramic substrate is an electrical insulation layer. The ceramic layer is made of aluminum oxide or silicon nitride, for example.

[0015] The lower copper layer of the respective ceramic substrate is configured to be connected to a heat sink or a cooling plate of the power core for heat dissipation. In other words, the lower copper layer of the respective ceramic substrate is designed for cooling connection. The lower copper layer is to be understood as the back or underside of the package, which is, for example, integrally connected to the heat sink. The heat sink is preferably part of the electronic power core. The upper copper layer of the respective ceramic substrate is at least electrically connected to other components of the half-bridge package.

[0016] The busbar arrangement is a structured arrangement of busbars or conductor tracks, for example in the form of stamped and formed sheets and / or metal strips, to establish electrical connections between different components. The busbars serve to efficiently and reliably transmit high currents between the various components of the motor control system. The busbars can be made of copper or aluminum and provide low impedance for power transmission. The leadframes can be part of the busbar arrangement in sections. Alternatively, the conductor tracks or sheets of the busbar arrangement can be electrically connected to the associated leadframes.

[0017] The busbars of the busbar arrangement are each arranged as rails in multiple levels and made of an electrically conductive material, particularly metal. The busbars can be formed by stamping and forming. In a compact design, insulating layers or foils can be arranged between the busbars to provide electrical insulation. Externally arranged insulating foils can serve to shield and protect the busbars from external influences and / or neighboring components. The layer structure of the busbar arrangement can be designed in different ways and adapted to the spatial conditions, the arrangement of the high and low sides, and the requirements.

[0018] Current symmetry can be achieved by appropriately arranging the leadframes and the associated load connections, i.e., by selecting a suitable topology for the respective half-bridge package. A half-bridge package is current-symmetrical when the current flow within it is evenly distributed. This means that the current in different paths or branches of a circuit is always the same. Current symmetry ensures that the circuit functions properly and that no undesirable effects occur.

[0019] The respective half-bridge package can be encapsulated by injection molding to insulate the components of the half-bridge package. In other words, the half-bridge package is encapsulated in a so-called molding process. The molding process is a method in which a plastic housing consisting of insulating material is formed around one or more power semiconductors of the half-bridge package. The encapsulation protects the power semiconductors in particular from external influences such as moisture and dust. The molding process involves injecting liquid plastic as insulating material into a mold in which the components of the half-bridge package are placed. After the plastic has hardened, the mold or tool is removed, protecting the half-bridge package. The half-bridge package is encapsulated, for example, using transfer or compression molding.

[0020] In transfer molding, a defined amount of a molding material, typically a thermoset or thermoplastic, is poured into a mold cavity through a sprue. During transfer molding, the mold walls are typically heated to a temperature above the melting temperature of the molding material to ensure good flow properties within the cavity. A wide variety of thermoplastics and thermosets are suitable for transfer molding.

[0021] A power semiconductor is a semiconductor device capable of handling high electrical currents and voltages. Power semiconductors are designed to switch and control large amounts of power.

[0022] The expression "arranged in an elliptical shape" means that the power semiconductors are placed on the surface of the corresponding segment of the upper copper layer along an imaginary ellipse, using the major and minor axes of the ellipse as a reference. The power semiconductors are thus arranged radially around a common center, with the respective radius—i.e., the distance between a center and / or center of gravity of the power semiconductor and the common center—being based on the ellipse. This method combines a radial arrangement with the shape of an ellipse. In its simplest form, the power semiconductors are arranged in a circle on the corresponding segment, with the power semiconductors arranged radially around a common center and at equal distances from it.

[0023] Although the leadframe can be connected to the half-bridge package via a single load connection, it can be advantageous to achieve current symmetry if one or more leadframes are each connected to the half-bridge package via two or more assigned load connections. If necessary due to installation space constraints and / or to improve current symmetry within the half-bridge package, the first segment is connected to the first leadframe via two mirror-symmetrical first load connections, wherein the first load connections are arranged mirror-symmetrically on the first segment. By providing preferably two first load connections, which are preferably arranged on opposite sides of the half-bridge package, the power supply can be split and routed through the half-bridge package. This allows the half-bridge package to be made more compact.This allows the power density to be increased while maintaining a compact design.

[0024] The busbar is a connecting plate whose potential is assigned to the second leadframe. The busbar is designed to electrically couple, at least indirectly, the first power semiconductors assigned to the first segment with the power semiconductors assigned to the second segment. The number of first power semiconductors always corresponds to the number of second power semiconductors. Furthermore, the arrangement of the two power semiconductor groups is preferably substantially identical to ensure current symmetry.

[0025] The busbar preferably contacts the first power semiconductors and has two mirror-symmetrical connecting legs that are connected to the second segment. The connecting legs are to be understood as load connections between the two segments of the upper copper layers. The connecting legs are arranged at a distance from one another on the busbar.

[0026] Alternatively or additionally, the second power semiconductors are connected to the third leadframe via two mirror-symmetrical third load terminals, wherein the third load terminals are arranged mirror-symmetrically on a further busbar that contacts the second power semiconductors and is connected to a third segment of the upper copper layer. The further busbar is also a connecting plate whose potential is assigned to the third leadframe. The further busbar is also at least electrically connected to the ceramic substrate. The third segment of the upper copper layer is arranged at a distance from the second segment. With regard to the advantages, reference is made to the above statements regarding the first segment with the mirror-symmetrical first load terminals, which apply equally here.

[0027] Furthermore, alternatively or additionally, the second segment is connected to the second leadframe via two mirror-symmetrically formed second load terminals, wherein the second load terminals are arranged mirror-symmetrically on the second segment and connected to one another via a leg. Regarding the advantages, reference is made to the above explanations regarding the first segment with the mirror-symmetrically formed first load terminals, which apply equally here.

[0028] The respective busbar preferably has means for contacting the ceramic substrate. This can be achieved via arms, connectors, or connecting sections of the respective busbar. This allows for thermal coupling with the ceramic substrate to control the temperature of the busbars and the components connected to them.

[0029] With regard to three half-bridge packages, the leadframes assigned to the DC plus, DC minus, or AC connection can each be connected to one another or made from a single piece, i.e., from a single sheet. In this sense, the first leadframes of the half-bridge packages are preferably formed as a single piece. A one-piece connection can, for example, be a one-piece design. An initially multi-piece design is also conceivable, wherein the sheets are electrically connected to one another, in particular by means of a material bond, in order to form the respective leadframe. Alternatively or additionally, the third leadframes of the half-bridge packages are formed as a single piece.

[0030] In a further development of the invention, the power core further comprises a DC link capacitor that is electrically connected to the busbar arrangement. In an inverter, the DC link capacitor serves to ensure a stable voltage supply for the inverter. The DC link is a type of buffer storage for electrical energy and plays an important role in the conversion of direct current (D0) to alternating current (A0) in the inverter. The DC link capacitor acts as a filter for the direct current coming from the inverter's rectifier unit. It smoothes the pulsed DC voltage generated by the rectifier circuit, thus ensuring a more stable DC voltage in the DC link. The DC link capacitor serves as a temporary energy storage device. During rectification, the DC link capacitor is charged, and during inversion, it releases energy.This enables a continuous and stable AC output, even when the DC power supply is subject to fluctuations. The DC link capacitor helps stabilize the generated AC voltage by compensating for fluctuations, thus ensuring a smooth AC output.

[0031] Preferably, each half-bridge package is provided with a first control terminal for gate control of the first power semiconductors and a second control terminal for gate control of the second power semiconductors. The respective control terminal is to be understood as a gate-source terminal for the group of first power semiconductors or the group of second power semiconductors. The control terminal can be designed as a gate slider of the first or second segment of the ceramic substrate. The first or second segment of the upper copper layer of the ceramic substrate thus has a separate control terminal.

[0032] The respective control connection preferably comprises two connection elements for signal contacting, which are electrically connected to the associated power semiconductors. The signal contacting can be made via so-called topside contacts, press-fit connections, sleeves, or solder pins. This can minimize stray inductance. Furthermore, signal contacting can be made via a separate leadframe with bond wires. The connection elements are therefore provided for gate control of the high-side or low-side of the half-bridge package. The power semiconductors of the high-side or low-side of the respective half-bridge package are controlled at least indirectly via the connection elements. The connection elements are connected to the power semiconductors in a signal-transmitting manner. The connection elements can be electrically connected to the power semiconductors via bond wires or the like.

[0033] Furthermore, the respective control terminal preferably comprises a Kelvin-source terminal element. The Kelvin-source terminal is a special terminal configuration for controlling power semiconductors. This configuration enables more precise control of the respective power semiconductor and helps minimize problems associated with switching losses, in particular voltage drops and parasitic capacitances between the gate and source terminals, which can lead to delays in signal transmission and slower switching speeds. By separating the control signal from the actual source current path, more precise and stable control of the gate voltage is achieved. This is advantageous in applications where fast switching operations and precise timing requirements are required.

[0034] In a further development of the invention, the power core further comprises a heat sink to which the ceramic substrate of the respective half-bridge package is thermally connected. The three half-bridge packages are arranged on the heat sink and thermally connected to it. Thus, the power core or inverter is a fluid-temperature-controlled, in particular fluid-cooled, power core or inverter. The heat sink can alternatively be part of a cooling device of the inverter.

[0035] The respective half-bridge package can be connected to the heat sink, for example, using so-called nanowire technology, by sintering, soldering, or pressing using an organic insulator. The respective half-bridge package can be connected directly to the heat sink via a lower copper layer of the ceramic substrate. Alternatively, an insulation layer can be arranged between the respective half-bridge package, in particular the lower copper layer of the ceramic substrate, and the heat sink. Regardless of the number of half-bridge packages, all half-bridge packages can be arranged and cooled on a common heat sink, for example designed as a cooling plate or the like. In a second aspect of the invention, an inverter according to the invention for an electric drive axle of a motor vehicle comprises a power core according to the first aspect of the invention.The inverter is designed, in particular, as an inverter. An inverter is a power converter that converts direct current (DC) into alternating current (AC). The inverter is preferably a fluid-temperature-controlled, in particular fluid-cooled, inverter, whose heat sink comes into contact with a temperature-control fluid, in particular a cooling fluid, at least in some areas or sections.

[0036] In a third aspect of the invention, an electric drive axle according to the invention, also called an E-axle, comprises an electric machine and an inverter according to the second aspect of the invention or a power core according to the first aspect of the invention. The electric machine is a three-phase electric machine. The preferably fluid-cooled inverter forms a motor controller that controls the electric machine. The inverter is therefore designed in particular to control a three-phase electric machine. In addition to the electric machine, the electric drive axle can comprise an optional transmission to provide a torque and a speed for driving a drive wheel of the motor vehicle. The electric machine is supplied with electrical energy from an energy storage device.

[0037] The electric drive axle, the inverter, and / or the power core can be advantageously used in a motor vehicle. The motor vehicle is, in particular, an electric vehicle or a hybrid vehicle and can, in particular, comprise a motorcycle, a passenger car, a truck, or a bus. The motor vehicle comprises at least two axles. Preferably, two axles are provided, with at least one of the axles being an electric drive axle and being drivable by at least one electric machine.

[0038] The above definitions as well as explanations of technical effects, advantages, and advantageous embodiments of the power core according to the invention according to the first aspect of the invention also apply mutatis mutandis to the inverter according to the invention according to the second aspect of the invention, to the electric drive axle according to the invention according to the third aspect of the invention, and to the motor vehicle according to the invention according to the fourth aspect of the invention, and vice versa. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention.

[0039] To the extent that elements are designated by numbering, for example, "first component," "second component," and "third component," this numbering is intended purely for differentiation in the designation and does not represent any interdependence of the elements or a mandatory sequence of the elements. This means, in particular, that a device does not have to have a "first component" in order to have a "second component." The device may also comprise a "first component" and a "third component," but without necessarily having a "second component."

[0040] The invention will now be described in more detail with reference to the accompanying figures, in which:

[0041] Figure 1 is a highly schematic view of a motor vehicle with an electric drive axle;

[0042] Figure 2 shows an exemplary motor control of the drive axle, comprising a power core according to the invention according to a first embodiment;

[0043] Figure 3 is a schematic perspective view of the power core according to the invention shown in Figure 2;

[0044] Figure 4a is a schematic perspective view of an exemplary half-bridge package and a busbar arrangement of the power core according to the invention according to Figure 2 and Figure 3;

[0045] Figure 4b is a schematic perspective view of the half-bridge package according to Figure 4a without showing the leadframes;

[0046] Figure 4c is a schematic top view of the half-bridge package according to Figures 4a and 4b; Figure 5 is a schematic top view of the ceramic substrate of the half-bridge package according to Figures 4a to 4c and individual load terminals;

[0047] Figure 6 is a highly schematic representation of a gate control of the half-bridge package according to Figure 4a to Figure 5, connected to power semiconductors;

[0048] Figure 7 is a schematic perspective view of the half-bridge package of the power core according to the invention according to a second embodiment;

[0049] Figure 8 is a schematic perspective view of the half-bridge package of the power core according to the invention according to a third embodiment;

[0050] Figure 9 is a schematic perspective view of the half-bridge package of the power core according to the invention according to a fourth embodiment; and

[0051] Figure 10 shows a schematic perspective view of the half-bridge package of the power core according to the invention according to a fifth embodiment; wherein identical or similar components are provided with the same reference numerals.

[0052] Figure 1 shows an electric drive axle 100 in a motor vehicle 105. The motor vehicle 105 may additionally include an internal combustion engine 110 connected to a drive wheel 120 of the motor vehicle 105 via a transmission 115. In this case, the motor vehicle 105 would be a hybrid vehicle.

[0053] The electric drive axle 110 comprises an electric machine 125, which can also act on the drive wheel 120, preferably by means of the transmission 115. Furthermore, an inverter 130 according to the invention can be provided in the form of an inverter, which can be fed with electrical energy from an electrical energy storage device 135. The electrical energy storage device 135 is preferably electrochemically constructed, but a fuel cell or another power source can also be used, for example. The inverter 130 is preferably designed to provide the electric machine 125 with phase-shifted alternating currents. The machine 125 is implemented, for example, as a permanent magnet synchronous machine, but other embodiments are also possible. The voltages and frequencies of the alternating currents provided can be determined such that the electric machine 125 converts orrotates at a predetermined speed. A field-oriented control can be implemented to control the direction of rotation and speed. The nominal voltage of the electrical energy storage device 135 is typically several hundred to over 1000 V. The current through the electrical machine 125 can be several hundred A.

[0054] Figure 2 shows the inverter 130 with a power core 200 according to the invention, comprising three half-bridge packages 205, each forming a half-bridge and being controllable, for example, by means of a common control device 210. The inverter 130 is configured to control the rotational behavior of the electric machine 125 and typically operates digitally using a microcomputer. An inverter is an electronic circuit used to control the direction or magnitude of the electrical current. Inverters are typically used to convert alternating current (AC) into direct current (DC), or vice versa. The inverter 130 can function as a rectifier or inverter.

[0055] Each half-bridge package 205 comprises two halves 215, 220, wherein the two halves 215, 220 are connected in series between DC voltage potentials of the energy storage device 135 as shown. A DC link capacitor 225 is preferably provided between the potentials. A center tap 230 between the halves 215, 220 of the respective half-bridge package 205 is connected to an associated phase of the electric machine 125. The upper half 215 of the semiconductor package 205 lies between a high potential of the energy storage device 135 and the center tap 230, and the lower half 220 of the semiconductor package 205 lies between the center tap 230 and a low potential of the energy storage device 135.

[0056] The halves 215, 220 of the respective semiconductor package 205 can be controlled independently of one another, each like an electrical switch, to close or open. The control device 210 is configured to alternately close and open the halves 215, 220 of the semiconductor package 205, so that at no time are both halves 215, 220 of a semiconductor package 205 closed. A voltage that occurs at the center tap 230 of the respective semiconductor package 205 depends on a ratio of the duty cycles of the upper half 215 and the lower half 220 of the respective semiconductor package 205. During normal operation of the electrical machine 125, predetermined currents can thus be controlled through the halves 215, 220 of the semiconductor package 205.

[0057] Figure 3 shows the electronic power core 200 according to Figure 2 in a top view. The power module 200 comprises a plate-shaped heat sink 300 on which the three half-bridge packages 205 are arranged. Each half-bridge package 205 is assigned as a B2 package to a switching position of the power module 200. Alternatively, the power module 200 can also be arranged with six half-bridge packages 205 together on the heat sink 300, with two half-bridge packages 205 each being assigned as B2 packages to a switching position of the power module 200. The half-bridge packages 205 are designed identically regardless of their number, which is why only one exemplary half-bridge package 205 is shown and described below in Figures 4a ff. The other half-bridge packages 205 are designed analogously.

[0058] According to Figure 3, the power core 200 further comprises a busbar arrangement 305 with a first leadframe 310, a second leadframe 311, and a third leadframe 312, wherein the leadframes 310, 311, 312 are electrically connected to the half-bridge packages 205. A continuous, one-piece first leadframe 310 and a continuous, one-piece third leadframe 310 are provided for all three half-bridge packages 205. In addition, a second leadframe 311 is provided for each half-bridge package 205.

[0059] The first leadframe 310 is designed here as a "DC plus connection." The DC plus connection denotes the positive direct current (DC) connection of the half-bridge package and forms the "drain" side. The DC plus connection is connected to the positive pole of the energy storage device 135 as the power source. The respective second leadframe 311 is designed here as an "AC connection." The "AC connection" refers to the connection for alternating current (AC) or the "source" side of the half-bridge package 205. The third leadframe 312 is also designed as a "DC minus connection." The DC minus connection is the negative direct current connection of the half-bridge package 205. In a DC system, it is connected to the negative pole of the energy storage device 135.The first and third leadframes 310, 312, i.e., the DC plus and DC minus connections, are connected to the intermediate circuit capacitor 225, although the exact structure of the intermediate circuit capacitor 225 is not described in detail here. The intermediate circuit capacitor 225 is therefore electrically connected to the busbar arrangement 305, specifically, the intermediate circuit capacitor 225 is connected to the first and third leadframes 310, 312 of the busbar arrangement 305.

[0060] Figure 4a shows an exemplary half-bridge package 205 together with sections of the leadframes 310, 311, 312. Figures 4b and 4c show this half-bridge package 205 without the busbar arrangement 305 from different perspectives. Figure 5 shows this half-bridge package 205 only partially in order to illustrate the arrangement of power semiconductors of the half-bridge package 205.

[0061] According to Figure 4a, each half-bridge package 205 has a ceramic substrate 400 with a ceramic layer 405 between a lower copper layer 410 and an upper copper layer 415. The upper copper layer 415 is segmented and comprises a first segment 420 and a second segment 425 spaced therefrom, wherein one of these segments 420, 425 is assigned to a high side, i.e., one half 215, 220 of the half-bridge package 205, and the other segment 425, 420 is assigned to a low side of the half-bridge package 205, i.e., the other half 220, 215 of the half-bridge package 205.

[0062] According to Figures 4a to 4c and in conjunction with Figure 5, the first segment 420 is connected to the first leadframe 310 according to Figure 4a via two mirror-symmetrical first load connections 430, 431 arranged to the left and right of the first segment 420. The second segment 425 is connected to the second leadframe 311 via two mirror-symmetrical second load connections 435, 436 arranged to the left and right of the second segment 425. The second load connections 435, 436 are mirror-symmetrical on the second segment 425, arranged at a distance from one another, and are connected to one another in one piece via a leg 437 as a connecting piece.

[0063] According to Figure 5, six first power semiconductors 500 are arranged at least in an elliptical shape on the first segment 420. A corresponding number of second power semiconductors 505 are arranged on the second segment 425, also in an elliptical shape. According to Figures 4a to 4c, the first power semiconductors 500 are connected to the second segment 425 via a first busbar 440, wherein the first busbar 440 contacts the first power semiconductors 500 and has two mirror-symmetrical connecting legs 443 for contacting the second segment 425. The second power semiconductors 505 are connected to the third leadframe 312 via two mirror-symmetrical third load terminals 445, 446. The third load terminals 445, 446 are mirror-symmetrical, i.e., to the left and right of the second segment 425, and are arranged on a second busbar 450, which contacts the second power semiconductors 505.Both busbars 440, 450 have a central connecting web 455 as shown in Figure 4b and Figure 4c.

[0064] Furthermore, a third segment 452 of the upper copper layer 415 of the ceramic substrate 400 is provided, via which the second busbar 450 is coupled, in particular thermally, to the ceramic substrate 400 by connecting legs 453. The third segment 452 lies on the longitudinal axis of the ceramic substrate 400 and is arranged on a side of the second segment 425 opposite the first segment 420.

[0065] In the first embodiment, the third load terminals 445, 446 are spatially arranged between the first load terminals 430, 431 and the second load terminals 435, 436. The second load terminals 435, 436 are arranged on the front side of the half-bridge package 205, while the first and third load terminals 430, 431, 445, 446 are arranged on opposite sides of the half-bridge package 205. Figure 6 illustrates the gate control of the half-bridge package 205, here using the example of the first power semiconductor 500, whereby this applies analogously to the second power semiconductor 505 of the half-bridge package 205. Each half-bridge package 205 has a first control terminal 600 for gate control for the first power semiconductor 500 and a second control terminal 600 for gate control for the second power semiconductor 505. In this case, the contacting is implemented in a wired or conductor-based manner.The respective control terminal 600 comprises two connection elements 605, 606 as so-called "gate-source" connections for signal contacting with the associated power semiconductors 500, 505, as well as a Kelvin-source connection element 610, wherein the Kelvin-source connection element 610 is arranged between the two "gate-source" connections. The control terminal 600 is also symmetrical. The connections can be interchanged as desired and are not limited to the present variant. The control terminals 600 are each connected to the control device 210 for signal transmission in order to control the halves 215, 220 of the half-bridge package 205.

[0066] The following description of the further exemplary embodiments essentially focuses on distinguishing features from the first exemplary embodiment according to Figures 1 to 6. Furthermore, what has been said about the first exemplary embodiment applies analogously to the further exemplary embodiments.

[0067] In a second exemplary embodiment according to Figure 7, an alternative configuration of the respective control terminal 600 is shown, wherein the respective control terminal 600 is formed in this case by second further segments 700, 705 of the upper copper layer 415. Control pins or the like can be arranged on the fourth and fifth segments 700, 705. Furthermore, an alternative arrangement of the load terminals is shown in Figure 7. In this case, the first load terminals 430, 431 are arranged spatially between the third load terminals 445, 446 and the second load terminals 435, 436. Furthermore, a connection of the first busbar 440 to the ceramic substrate 400 is divided into two connection sections 710, 711, which are arranged in the corners of the ceramic substrate 400 and are electrically and thermally connected to a respective sixth segment 715 of the upper copper layer 415.The connecting legs 453 of the second busbar 450 are configured analogously to the connection sections 710, 711 of the first busbar 440 and are arranged on the opposite side of the ceramic substrate 400 and are electrically and thermally connected to corresponding separate sixth segments 715 of the upper copper layer 415. This ensures and / or improves current symmetry within the half-bridge package 205. The second load terminals 435, 436 and the third load terminals 445, 446 are arranged or connected to the front side of the half-bridge package 205 on opposite sides, while the first load terminals 430, 431 are arranged laterally on opposite sides of the half-bridge package 205. In addition, in contrast to the first embodiment, the connecting webs of the busbars 455 and the leg for connecting the second load terminals 435, 436 are omitted.Rather, the busbars 440, 450 are each essentially horseshoe-shaped or designed in the shape of the letter Omega (Q) of the classical Greek alphabet. Furthermore, the first busbar 440 has only a single connecting leg 443 for connecting to the second segment 425 of the upper copper layer 415.

[0068] According to the third exemplary embodiment shown in Figure 8, it is illustrated that the first busbar 440 has four connecting legs 443 for connecting to the second segment 425 of the upper copper layer 415. This further improves the current symmetry and reduces the load per connecting leg 443. Furthermore, in comparison to Figure 4b, the leg connecting the second load terminals 435, 436 is omitted here. Thus, the two second load terminals 435, 436 are separate components, each of which is connected to the second leadframe 311.

[0069] The fourth embodiment according to Figure 9 is essentially identical to the third embodiment according to Figure 8. The difference here is that the busbars 440, 450 have a central connecting web 455, similar to Figure 4b. This further improves the current symmetry. For clarity, the second load terminals 435, 436 have been omitted here.

[0070] The fifth exemplary embodiment according to Figure 10 is intended to illustrate that, depending on requirements or spatial conditions, the "high side" can be interchanged with the "low side." In other words, in contrast to the first exemplary embodiment according to Figures 4a to 5, the first segment 420 of the upper copper layer 415, which accommodates the first power semiconductors 500, is arranged on the right, and the second segment 425 of the upper copper layer 415, which accommodates the second power semiconductors 505, is arranged on the left. This results in the first load terminals 430, 431 being spatially arranged between the third load terminals 445, 446 and the second load terminals 435, 436. The second load terminals 435, 436 and the third load terminals 445, 446 are each arranged on opposite sides of the half-bridge package 205, while the first load terminals 430, 431 are arranged on opposite sides of the half-bridge package 205.The thermal coupling of the busbars 440, 450 to the upper copper layer 415 is essentially analogous to the exemplary embodiment according to Figure 7. The difference here is that the connecting legs 710, 711 of the first busbar 440 are connected to a single seventh segment 1000 of the upper copper layer 415 of the ceramic substrate 400, wherein the second load terminals 435, 446 are also connected to this segment 1000. The additional segments with the reference numerals 715 and 1000 can be used to control the temperature of the load terminals 445, 446 and 435, 436, respectively, since heat is absorbed and dissipated by the ceramic substrate 400 before the heat can heat up the leadframes 310, 311, 312 and possibly other components of the busbar arrangement 305.

[0071] For the sake of completeness, it should be noted that although the figures presented here depict the respective half-bridge package 205 after its manufacture as a separately manageable unit, it is not shown that the half-bridge package 205 is encapsulated by an insulating material, which forms a housing for the half-bridge package 205 in order to protect the individual components of the half-bridge package 205, where necessary, from interaction with one another and from external influences, in particular dirt and moisture. The encapsulation is produced by injection molding. The insulating material has been omitted for the sake of a better understanding of the invention.

[0072] Reference symbol

[0073] 100 electric drive axles

[0074] 105 Motor vehicle

[0075] 110 combustion engine

[0076] 115 gearboxes

[0077] 120 drive wheel

[0078] 125 electric machine

[0079] 130 inverters

[0080] 135 energy storage

[0081] 200 power core

[0082] 205 Half Bridge

[0083] 210 Control device

[0084] 215 Upper half-bridge package of the semiconductor bridge

[0085] 220 Lower half-bridge package of the semiconductor bridge

[0086] 225 DC link capacitor

[0087] 230 center tap

[0088] 300 heat sinks

[0089] 305 busbar arrangement

[0090] 310 First leadframe

[0091] 311 Second leadframe

[0092] 312 Third leadframe

[0093] 400 ceramic substrate

[0094] 405 ceramic layer

[0095] 410 Lower copper layer

[0096] 415 Upper copper layer

[0097] 420 First segment of the upper copper layer

[0098] 425 Second segment of the upper copper layer

[0099] 430 First load connection

[0100] 431 First load connection 435 Second load connection

[0101] 436 Second load connection

[0102] 437 thighs

[0103] 440 First busbar

[0104] 443 Connecting leg of the first busbar

[0105] 445 Third load connection

[0106] 446 Third load connection

[0107] 450 Second busbar

[0108] 452 Third segment of the upper copper layer

[0109] 453 Connecting leg of the second busbar

[0110] 455 connecting bridge

[0111] 500 First power semiconductor

[0112] 505 Second power semiconductor

[0113] 600 control connection

[0114] 605 First connection element of the control connection

[0115] 606 Second connection element of the control connection

[0116] 610 Kelvin source connection element

[0117] 700 Fourth segment of the upper copper layer

[0118] 705 Fifth segment of the upper copper layer

[0119] 710 First connection section

[0120] 711 Second connecting section

[0121] 715 Sixth segment of the upper copper layer

[0122] 1000 Seventh segment of the upper copper layer

Claims

Patent claims 1. Power core (200) for an inverter (130) of an electric drive axle (100), the power core (200) comprising a busbar arrangement (305), a first leadframe (310), a second leadframe (311) and a third leadframe (312) and three half-bridge packages (205), each half-bridge package (205) having a ceramic substrate (400) with a ceramic layer (405) between a lower copper layer (410) and an upper copper layer (415), the upper copper layer (415) comprising a first segment (420) and a second segment (425) spaced therefrom, a plurality of first power semiconductors (500) being arranged at least in an elliptical shape on the first segment (420), a number of second power semiconductors corresponding to the first power semiconductors (500) Power semiconductors (505) are arranged at least in elliptical shape on the second segment (425),wherein the first segment (420) is connected to the first leadframe (310) via a first load terminal (430), wherein the first power semiconductors (500) are connected to the second segment (425) via a busbar (440), wherein the second segment (425) is connected to the second leadframe (311) via a second load terminal (435), and wherein the second power semiconductors (505) are connected to the third leadframe (312) via a third load terminal (445).

2. Power core (200) according to claim 1, wherein the first segment (420) is connected to the first leadframe (310) via two mirror-symmetrically formed first load terminals (430, 431).

3. Power core (200) according to claim 1 or claim 2, wherein the busbar (440) contacts the first power semiconductors (500) and has two mirror-symmetrical connecting legs (443) which are connected to the second segment (425).

4. Power core (200) according to one of the preceding claims, wherein the second segment (425) has two mirror-symmetrically formed second load locks (435, 436) is connected to the second leadframe (311), wherein the second load terminals (435, 436) are arranged mirror-symmetrically on the second segment (425) and are connected to one another via a leg (437).

5. Power core (200) according to one of the preceding claims, wherein the second power semiconductors (505) are connected to the third leadframe (312) via two mirror-symmetrically formed third load terminals (445, 446), wherein the third load terminals (445, 446) are arranged mirror-symmetrically on a further busbar (450) which contacts the second power semiconductors (505) and which is connected to a third segment (510) of the upper copper layer (415).

6. Power core (200) according to one of the preceding claims, wherein the respective busbar (440, 450) has means for contacting the ceramic substrate (400).

7. The power core (200) of any preceding claim, further comprising an intermediate circuit capacitor (225) electrically connected to the busbar arrangement (305).

8. Power core (200) according to one of the preceding claims, wherein for each half-bridge package (205) a first control terminal (600) for gate control for the first power semiconductors (500) and a second control terminal (600) for gate control for the second power semiconductors (505) are provided.

9. Power core (200) according to claim 8, wherein the respective control terminal (600) comprises two connection elements (605, 605) for signal contacting, which are electrically connected to the associated power semiconductors (500, 505).

10. Power core (200) according to one of the preceding claims, wherein the respective control terminal (600) comprises a Kelvin source terminal element (610).

11. Power core (200) according to one of the preceding claims, further comprising a heat sink (300) to which the ceramic substrate of the respective half-bridge package (205) is thermally connected.

12. Inverter (130) for an electric drive axle (100) of a motor vehicle (105), comprising a power core (200) according to one of the preceding claims.

13. Electric drive axle (100) comprising an electric machine (125) and an inverter (130) according to claim 12.

14. Motor vehicle (105) comprising an electric drive axle (100) according to claim 13.

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