Half-bridge switch arrangement

Abstract

The invention relates to a half-bridge switch arrangement with a plurality of parallel-connected half-bridges, each half-bridge comprising a first semiconductor switching element and a second semiconductor switching element, comprising: a plurality of half-bridge units (100), each half-bridge unit comprising one of the first semiconductor switching elements (110), one of the second semiconductor switching elements (120), and a support element, wherein the respective first semiconductor switching element (110) and the respective second semiconductor switching element (120) are arranged on the respective support element, a heat sink (180), wherein the plurality of half-bridge units (100) are in thermal contact with the heat sink (180), a first busbar to which a first terminal of each of the first semiconductor switching elements (110) of the plurality of half-bridge units (100) is electrically connected, a second busbar,a third busbar, to which a second terminal of each of the first semiconductor switching elements (110) of the plurality of half-bridge units (100) and a first terminal of each of the second semiconductor switching elements (120) of the plurality of half-bridge units (100) are electrically connected, a third busbar, to which a second terminal of each of the second semiconductor switching elements (20) of the plurality of half-bridge units (100) is electrically connected.

Description

[0001] The present invention relates to a half-bridge switch arrangement. Background of the invention

[0002] Half-bridge switch arrangements can be used, for example, in power converters, such as inverters for the mutual conversion between direct and alternating voltages. For example, such half-bridge switch arrangements can be used in power modules in (motor) vehicles to convert a voltage between a direct voltage on-board electrical system and an electrical machine that can be operated with multi-phase alternating voltage.

[0003] Such half-bridge switch arrangements have one half-bridge per phase, each with a high-side switch and a low-side switch. Individual, discrete semiconductor switching elements, such as individual transistors such as FETs, MOSFETs, IGBTs, etc., can be used as the high-side or low-side switches. Furthermore, a plurality of such half-bridges, each with a first discrete semiconductor switching element and a second discrete semiconductor switching element, can be connected in parallel per phase. The first semiconductor switching elements of these parallel-connected half-bridges form the high-side switch, and the second semiconductor switching elements of these parallel-connected half-bridges form the low-side switch.

[0004] By connecting half-bridges in parallel in this way, high power scalability and high power or current levels can be achieved. However, this often results in a high DC link inductance and thus a high total inductance of the commutation loop. It can also often prove difficult to cool such half-bridge switch arrangements sufficiently to maintain temperatures at desired values ​​at high currents and high switching frequencies.

[0005] It is therefore desirable to provide an improved half-bridge switch arrangement with parallel connections of individual half-bridges. Disclosure of the invention

[0006] Against this background, a half-bridge switch arrangement with the features of patent claim 1 is proposed. Advantageous embodiments are the subject of the subclaims and the following description.

[0007] The half-bridge switch arrangement comprises a plurality of parallel-connected half-bridges, each half-bridge having a first semiconductor switching element and a second semiconductor switching element. Accordingly, the half-bridge switch arrangement comprises a plurality of first semiconductor switching elements and a plurality of second semiconductor switching elements, the number of first semiconductor switching elements and the number of second semiconductor switching elements expediently corresponding to the number of half-bridges. The first semiconductor switching elements of the parallel-connected half-bridges expediently form a high-side switch, and the second semiconductor switching elements of the parallel-connected half-bridges expediently form a low-side switch. The individual semiconductor switching elements can each be designed, for example, as a transistor, e.g., as an FET, MOSFET, IGBT, etc.

[0008] The half-bridge switch arrangement comprises a plurality of half-bridge units or half-bridge modules, each half-bridge unit comprising one of the first semiconductor switching elements, one of the second semiconductor switching elements, and a carrier element. The respective first semiconductor switching element and the respective second semiconductor switching element are arranged on the respective carrier element. In particular, a half-bridge unit is thus provided for each of the parallel-connected half-bridges. The plurality of first and second semiconductor switching elements of the half-bridges are each installed in pairs on one of the half-bridge units. The carrier element can, for example, be plate-shaped or planar, and the two semiconductor switching elements can be arranged on the same side of this plate-shaped carrier element.

[0009] The half-bridge switch arrangement further comprises a heat sink, which may, for example, be fluid-cooled and may, for example, have an inlet and outlet for a corresponding cooling fluid. The cooling fluid may comprise oil, water, air, etc. The plurality of half-bridge units is in thermal contact with the heat sink, in particular with a first side of the heat sink. For example, the carrier elements can each be arranged on the heat sink with their side facing away from the respective semiconductor switching elements.

[0010] The half-bridge switch arrangement further comprises a first busbar, in particular a positive busbar (“B+ busbar”), a second busbar, in particular an output phase busbar, and a third busbar, in particular a negative busbar (“B- busbar”). In each case, a first terminal of the individual first semiconductor switching elements of the plurality of half-bridge units, in particular a drain terminal, is electrically connected to the first or positive busbar. In each case, a second terminal of the individual first semiconductor switching elements of the plurality of half-bridge units, in particular a source terminal, and in each case a first terminal of the individual second semiconductor switching elements of the plurality of half-bridge units, in particular a drain terminal, is electrically connected to the second busbar or the output phase busbar.A second terminal of each of the second semiconductor switching elements of the plurality of half-bridge units, in particular a source terminal, is electrically connected to the negative busbar. The individual busbars can be arranged or mounted on or relative to the heat sink, in particular such that a respective main extension plane of the individual busbars is oriented parallel or perpendicular to a main extension plane of the heat sink.

[0011] Each half-bridge unit is present as a separate assembly or is structurally separate prior to assembly in the half-bridge switch arrangement. This means that the half-bridge units can be prefabricated and then only need to be assembled with the other components to form the half-bridge switch arrangement. This simplifies production enormously. The half-bridge units therefore expediently represent modular components which can be combined with one another in a structurally simple, flexible and scalable manner in order to produce the half-bridge circuit, e.g. for an inverter phase. The heat sink is expediently provided and configured both for the mechanical fastening and for the cooling of the individual half-bridge units and thus the individual semiconductor switching elements. The respective carrier element of the individual half-bridge units can, for example, be made from a material with good thermal conductivity.be made of a material with low thermal resistance, e.g. copper, in order to be able to dissipate heat generated by the respective semiconductor switching elements installed on it and to transfer it effectively to the heat sink.

[0012] The invention provides a half-bridge switch arrangement with a low or as low as possible intermediate circuit inductance, a low or as low as possible commutation loop inductance and a low or as low as possible thermal impedance that can be effectively cooled.

[0013] By connecting the half-bridges in parallel, each with discrete switching elements, a high degree of power scalability can be achieved. The number of semiconductor switching elements or half-bridges can be conveniently selected to achieve a desired power or current. Furthermore, the use of discrete switching elements can keep the overall cost of the circuit low.

[0014] Conventionally, the use of parallel, discrete semiconductor switching elements can often lead to high parasitic inductance, which can be critical, for example, at high switching speeds of wide-bandgap semiconductors (WBGs) such as SiC or GaN. Such parasitic inductance can be minimized or at least reduced in the switch arrangement according to the invention.

[0015] The busbars are advantageously arranged close to one another, which reduces or minimizes inductive resistance. In particular, this allows for low DC link inductance and low total inductance of the commutation loop. Due to the short distances between the lines or connections of the switching elements and the busbars, the commutation loop can be optimized. The busbars can, for example, be laminated busbars with very low inductance, which enables the half-bridges to switch at very high speeds.

[0016] The arrangement of the heat sink allows the busbars to be cooled efficiently. Furthermore, the arrangement of the semiconductor switching elements on the heat sink allows for low thermal impedance, and the heat released by the switching elements can be effectively dissipated to the heat sink. In particular, the junction temperature of the switching elements can be maintained at a desired value at high currents and high switching frequencies.

[0017] According to one embodiment, the half-bridge switch arrangement further comprises at least one adhesion layer, which is arranged between the heat sink and each of the individual half-bridge units. For example, a separate adhesion layer can be provided for each of the half-bridge units, or a common adhesion layer can be provided for several or all of the half-bridge units. Using this adhesion layer(s), the individual half-bridge units can be firmly bonded or glued to the heat sink.

[0018] Alternatively or additionally, according to one embodiment, the half-bridge switch arrangement has at least one clamping element, which presses each of the half-bridge units against the heat sink. For example, a separate clamping element can be provided for each of the half-bridge units, wherein this clamping element exerts pressure, for example, on the two semiconductor switching elements of the respective half-bridge unit. Furthermore, a common clamping element can also be provided, for example, for several or all of the half-bridge units. With the aid of these clamping elements, the individual half-bridge units can be connected to the heat sink in a force-fitting manner, in particular in a manner that is easy to remove again.

[0019] According to one embodiment, the respective carrier element of each half-bridge unit is made of a ceramic material, e.g., aluminum oxide (Al2O3), aluminum nitride (AIN), or silicon nitride (Si3N4). Such carrier elements made of ceramic materials, for example, exhibit significantly greater robustness and service life when exposed to alternating electrical fields than plastics. Stresses on the carrier elements can be caused, in particular, by the use of fast-switching semiconductors, due to high switching frequencies and high edge steepness. The material of the carrier elements expediently represents a thermal interface material (TIM) between the respective semiconductor switching element and the heat sink, and can exhibit the lowest possible thermal resistance or the highest possible thermal conductivity.The thermal resistance between the switching elements, the carrier element, and the heat sink can thus be reduced, allowing heat to be effectively dissipated from the switching elements to the heat sink. For example, a layer of highly thermally conductive material, such as a copper layer, can be applied to the back of the respective carrier element facing away from the respective semiconductor switching elements to further improve heat conduction and heat dissipation.

[0020] According to one embodiment, first sections of a top side of the respective carrier element of each half-bridge unit, on which the respective first semiconductor switching element and the respective second semiconductor switching element rest, are each metallized. According to one embodiment, a second section of the top side of the respective carrier element of each half-bridge unit, on which the respective first semiconductor switching element and the respective second semiconductor switching element do not rest, is not metallized. Such first sections made of metallized ceramic can facilitate soldering of the lead frame of the semiconductor switching element.

[0021] According to one embodiment, the half-bridge switch arrangement has at least one capacitor unit, which in turn has at least one discrete capacitor element, in particular a plurality of parallel-connected, discrete capacitor elements. The at least one capacitor unit is arranged on a (second) side of the heat sink facing away from the plurality of half-bridge units. This capacitor unit or its capacitor elements represent, in particular, intermediate circuit capacitors. For example, the capacitor unit can provide primary intermediate circuit capacitors, which are connected in parallel to the entire parallel circuit of the half-bridges, and / or secondary or distributed intermediate circuit capacitors, which are connected in a distributed manner in parallel to individual half-bridges. A combination of primary and secondary intermediate circuit capacitors can, in particular, reduce the inductance of the commutation loop.The use of discrete capacitor elements in the capacitor unit offers high flexibility and scalability for the design of the primary and / or secondary DC link to achieve a desired power, voltage and current ripple.

[0022] The design and shape of the half-bridge switch arrangement can expediently provide sufficient space for these intermediate circuit capacitors, which can reduce the inductance of the commutation loop. By placing the intermediate circuit capacitors as close as possible to the switching elements, inductance can be reduced. Due to the short distances between the lines of the switching elements, the busbars, and the capacitor unit, the commutation loop can be optimized. The placement of the capacitor unit and its connection to the heat sink is easy to realize during the manufacturing process. In particular, the distance between the intermediate circuit capacitors and the switching elements can be as symmetrical as possible. The capacitor unit can be effectively cooled by the heat sink. For example, the capacitor unit can be cuboid-shaped and, for example,have a special cuboid-shaped capacitor element or a plurality of discrete capacitor elements arranged in a cuboid-shaped housing.

[0023] The size of the DC link can depend on several factors, e.g. the output current or output power of the inverter, the variation of the modulation index, the required voltage ripple and the ripple current carrying capacity of the individual capacitors. The number and size of the individual capacitor units as well as their respective capacitor elements can be flexibly changed depending on the application. The half-bridge switch arrangement offers flexibility for scaling the DC link for different power levels. The number of parallel capacitors can differ from the number of parallel half-bridges. The arrangement of the capacitors is very close to the half-bridge, which reduces the inductance of the commutation loop. The capacitors can be connected through the heat sink as well as through contact with an inverter housing, e.g.be cooled via a surface material or a filler, which further improves the cooling of the intermediate circuit.

[0024] According to one embodiment, the half-bridge switch arrangement further comprises a printed circuit board, wherein at least one recess is provided in the printed circuit board or in individual or multiple layers of the printed circuit board for a uniform distribution of a current flow through the printed circuit board and through the individual first semiconductor switching elements and the individual second semiconductor switching elements. The printed circuit board can in particular be a power printed circuit board or power board for supplying power to the semiconductor switching elements. For such a uniform distribution of the current flow, first impedances between the individual half-bridges connected in parallel in the first or positive current rail should expediently be identical or at least substantially identical. Furthermore, second impedances between the individual half-bridges connected in parallel in the second current rail orOutput phase busbars should each be identical or at least essentially identical. Furthermore, third impedances between the individual parallel-connected half-bridges in the third or negative busbar should each be identical or at least essentially identical. Furthermore, in particular, the individual first, second, and third impedances should generally be identical or at least essentially identical. For example, with the aid of an optimization algorithm, a respective shape, size, and position of the individual cutouts in the circuit board or in individual layers of the circuit board can be determined so that the individual first, second, and third impedances are as identical as possible.

[0025] According to one embodiment of the invention, the first busbar, the second busbar and the third busbar are each designed as individual components of a common circuit board, in particular as individual or multiple layers of the circuit board, which can be designed, for example, as a thick copper circuit board. This common circuit board can, for example, be designed as the (power) circuit board with cutouts explained above. Furthermore, the common circuit board can also be designed alternatively or in addition to the (power) circuit board with cutouts. The individual busbars are each designed, in particular, in the shape of a plate or have a planar surface and are arranged parallel to one another in the common circuit board. This common circuit board is connected to orarranged relative to the heat sink such that a main extension plane of the common circuit board is oriented perpendicularly or at least substantially perpendicularly to a respective main extension plane of the individual half-bridge units. In particular, the common circuit board is arranged on a third side of the heat sink, which adjoins perpendicularly or at least substantially perpendicularly to its first side, on which side in particular the half-bridge units are arranged. The common circuit board can expediently be cooled by the heat sink. The busbars are thus expediently arranged close to one another, whereby an inductive resistance can be reduced or kept as low as possible. In particular, a low intermediate circuit inductance and a low total inductance of the commutation loop can thus be achieved.Due to the short distances between the terminals of the switching elements and the busbars, the commutation loop can be optimized.

[0026] The common circuit board can further comprise, as a component, in particular a control board or power board, wherein at least one third terminal of each of the individual semiconductor switching elements can be electrically connected to this board. For example, each semiconductor switching element can comprise, as such at least one third terminal, a gate terminal and a Kelvin terminal (also referred to as a Kelvin source terminal or auxiliary source terminal). Such a Kelvin source terminal can decouple the path of a load current from the path of a control current, which can lead to improved switching properties. The individual terminals of the semiconductor switching elements can each be designed, in particular, as a pin or stud, which is led out of the respective semiconductor switching element, in particular parallel to its main extension plane.The individual connections can each be contacted with the respective busbar or circuit board, for example, by means of through-hole mounting or plug-in mounting (THT, or pin-in-hole technology, PIH). For this purpose, the respective connection pin expediently penetrates the respective busbar or circuit board through a corresponding connection opening, in particular in the form of a hole or bore, and is integrally connected to the respective busbar or circuit board on a (rear) side facing away from the busbars, in particular by a soldered or sintered connection. In a corresponding manner, individual connections of the capacitor unit(s) can also be electrically connected to the busbars in the shared circuit board.The common circuit board can also have other components, for example electrical connections for supplying power to the individual busbars.

[0027] According to one embodiment, the half-bridge switch arrangement further comprises an electrical heat sink insulating layer, which is expediently arranged between the heat sink and the common circuit board and by which the heat sink and the common circuit board are electrically insulated from one another. This heat sink insulating layer can be made of a material with good thermal conductivity or a material with low thermal resistance in order to effectively dissipate heat from the circuit board to the heat sink.

[0028] According to one embodiment of the invention, the first busbar, the second busbar, and the third busbar are each plate-shaped and arranged relative to the heat sink such that a respective main extension plane of the first busbar, the second busbar, and the third busbar is oriented parallel or at least substantially parallel to a respective main extension plane of the individual half-bridge units. According to this embodiment of the invention, the busbars are therefore not provided as layers of a common printed circuit board, but as individual, separately installed elements. For example, the individual busbars in this case can each be formed as copper plates or, for example, can be produced by welding onto a piece of metal such as copper.The sizes and dimensions of the individual busbars can be flexibly and freely selected and, for example, adapted to a given installation space. Individual or all busbars are expediently arranged close to one another relative to the heat sink and the semiconductor switching elements, thereby reducing or minimizing inductive resistance. In particular, this allows for low DC link inductance and low total inductance of the commutation loop. Due to the short distances between the terminals of the switching elements and the busbars, the commutation loop can be optimized.

[0029] According to one embodiment, one, several, or all of the first busbar, the second busbar, and the third busbar are arranged on a second side of the heat sink facing away from the plurality of half-bridge units, in particular on a side of the at least one capacitor unit facing away from the heat sink. Alternatively or additionally, one, several, or all of the first busbar, the second busbar, and the third busbar are arranged on a side of the plurality of half-bridge units facing away from the heat sink. The individual busbars can thus be arranged flexibly relative to the heat sink. For example, holding elements can be provided into which the individual busbars can be plugged or pushed, for example, in order to fix them in their orientation parallel to the main extension plane of the individual half-bridge units.Furthermore, these holding elements can be mechanically connected to the heat sink.

[0030] According to one embodiment, the first or positive busbar and the third or negative busbar are arranged parallel to one another on the second side of the heat sink facing away from the plurality of half-bridge units, in particular on the side of the at least one capacitor unit facing away from the heat sink. In particular, these two busbars can be electrically insulated from one another by an electrical busbar insulation layer. The second busbar or the output phase busbar is then arranged on the side of the plurality of half-bridge units facing away from the heat sink. For example, at least one first holding element can be provided for fixing the second busbar relative to the first side of the heat sink, and at least one second holding element can be provided for fixing the first and third busbars relative to the second side of the heat sink. The second busbar orThe output phase busbar thus has a greater distance to the heat sink and further to a housing of the half-bridge switch arrangement than the positive and negative busbars, whereby a reduction of the output common-mode capacitance can be achieved.

[0031] According to one embodiment, the half-bridge switch arrangement further comprises a printed circuit board or control board or power board, wherein this printed circuit board is arranged relative to the heat sink such that a main extension plane of the printed circuit board is oriented perpendicularly or at least substantially perpendicularly to a respective main extension plane of the individual half-bridge units. In particular, this printed circuit board can be designed as the (power) printed circuit board explained above with cutouts for a uniform distribution of the current flow through the printed circuit board and through the individual semiconductor switching elements. This printed circuit board is thus expediently oriented perpendicularly or at least substantially perpendicularly to the main extension plane of the first busbar, the second busbar, and the third busbar.In particular, this circuit board is arranged on the third side of the heat sink, which adjoins perpendicularly or at least substantially perpendicularly the first side on which the half-bridge units are arranged. Conveniently, the respective at least one third terminal of the individual semiconductor switching elements, in particular the respective gate and Kelvin terminal, can be electrically connected to the circuit board.

[0032] According to one embodiment, the first busbar, the second busbar, and the third busbar each have at least one contact element for electrical connection to the circuit board. In particular, these individual contact elements can each be fork-shaped, U-shaped, V-shaped, or Y-shaped. The individual contact elements can run from the respective plate-shaped busbar in the direction of the circuit board and be integrally connected to it there, in particular by a soldered or sintered connection. The circuit board can, in particular, have a plurality of layers, wherein individual or multiple layers can each be provided for supplying current to the first, second, or third busbar. The contact elements of the individual busbar are expediently electrically connected to the corresponding circuit board layer or layers, in particular by a soldered or sintered connection.

[0033] According to one embodiment, the half-bridge switch arrangement further comprises at least one electrical heat sink insulating layer, which electrically insulates the heat sink and the circuit board from each other. Such heat sink insulating layers are expediently made of a highly thermally conductive material with low thermal resistance in order to effectively dissipate heat from the circuit board to the heat sink.

[0034] The half-bridge switch arrangement or half-bridge power stage can be used in particular in a power converter or power converter circuit, for example in an inverter or inverter for mutually converting between direct and alternating voltages, wherein the parallel connection of the half-bridges can expediently be provided for one phase of a multi-phase alternating voltage. For this purpose, the first busbar and the third busbar can each be electrically connected, for example, to a direct voltage connection, and the second busbar to an alternating voltage connection.

[0035] The half-bridge switch arrangement is particularly suitable for use in a (motor) vehicle, expediently to convert a voltage between a DC on-board power supply and an electrical machine that can be operated with a multi-phase AC voltage. By connecting the half-bridges in parallel, the desired power or current strengths can be achieved, particularly in high-performance power converters in the vehicle sector. For this purpose, the first busbar and the third busbar can be connected to the DC on-board power supply, and the second busbar to a phase of the electrical machine. The half-bridge switch arrangement or its parallel connection of the individual half-bridges can thus be provided in particular for one phase of the electrical machine. The half-bridge switch arrangement then expediently represents a phase half-bridge for controlling one phase of the electrical machine.In a corresponding multi-phase inverter of a (motor) vehicle, a corresponding number of half-bridge switch arrangements can accordingly be expediently provided, e.g. three half-bridge switch arrangements for a three-phase electrical machine.

[0036] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0037] The invention is illustrated schematically in the drawing using exemplary embodiments and is described below with reference to the drawing. Short description of the drawings Fig. 1 shows schematically an embodiment of a half-bridge switch arrangement according to the invention as an electrical circuit diagram. Fig. 2 shows schematically in views a) to c) a half-bridge unit of an embodiment of a half-bridge switch arrangement according to the invention. Fig. 3 shows schematically in views a) to c) a heat sink with half-bridge units of an embodiment of a half-bridge switch arrangement according to the invention. Fig. 4 shows, in views a) to d), schematically an embodiment of a half-bridge switch arrangement according to the invention. Fig. 5 shows schematically in views a) to e) a further embodiment of a half-bridge switch arrangement according to the invention. Fig. 6 schematically shows a measurement scheme of an embodiment of a half-bridge switch arrangement as an electrical circuit diagram. Embodiment(s) of the invention

[0038] In Fig. 1, an embodiment of a half-bridge switch arrangement according to the invention is shown schematically as an electrical circuit diagram and designated by 1.

[0039] The half-bridge switch arrangement 1 is provided for rectification or inversion between DC voltage terminals 3, 4 and an AC voltage terminal 2 and has a plurality of parallel-connected half-bridges 5, each of which has a discrete first semiconductor switching element 11 and a discrete second semiconductor switching element 21, e.g., each in the form of a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT). The first semiconductor switching elements 11 of these parallel-connected half-bridges 5 form a high-side switch 10, and the second semiconductor switching elements 21 of these parallel-connected half-bridges 5 form a low-side switch 20.The number of parallel-connected half-bridges 5 and thus the number of individual first and second semiconductor switching elements 11 and 21 can each be selected in such a way as to achieve a desired power or a desired current.

[0040] The half-bridge switch arrangement 1 further comprises a first or positive bus bar 30, a second bus bar or output phase bus bar 70, and a third or negative bus bar 40. A drain terminal (first terminal) of the first semiconductor switching elements 11 is electrically connected to the positive bus bar 30. A source terminal (second terminal) of the first semiconductor switching elements 11 is electrically connected to the output phase bus bar 70. A drain terminal (first terminal) of the individual second semiconductor switching elements 21 is also electrically connected to the output phase bus bar 70. A source terminal (second terminal) of the second semiconductor switching elements 21 is electrically connected to the negative bus bar 40.

[0041] Furthermore, a plurality of first capacitor elements 51 are provided as a primary intermediate circuit 50, wherein these first capacitor elements 51 are each connected in parallel to the parallel circuit of the individual half-bridges 5. A plurality of second capacitor elements 51' are provided as a secondary or distributed intermediate circuit 50', wherein each of these second capacitor elements 51' is connected in parallel to one of the half-bridges 5.

[0042] For example, the arrangement 1 can be used in a (motor) vehicle, wherein the DC voltage terminals 3, 4 can be connected, for example, to a DC voltage on-board network and wherein, for example, a phase of an electrical machine can be connected to the AC voltage terminal 2. The electrical machine can be a multi-phase machine, for example, with typically three or more phases. For each of the phases, in particular, a Fig. 1 is provided with a plurality of parallel-connected half-bridges 5. Furthermore, a control unit for controlling the individual switching elements 11, 21 can be provided, wherein the control unit can control the gate terminals of the switching elements 11, 21 such that the current is directed in either the direct or inverse direction.

[0043] The individual half-bridges 5 with their respective first semiconductor switching element 11 and their respective second semiconductor switching element 21 are each provided in the form of a half-bridge unit or a half-bridge module, as described below with reference to Fig. 2 will be explained.

[0044] In the Fig. 2a and Fig. 2b, such a half-bridge unit for a half-bridge switch arrangement according to an embodiment of the invention is schematically shown and designated by 100.

[0045] The half-bridge unit 100 has a first semiconductor switching element 110, a second semiconductor switching element 120, and a carrier element 106, wherein the first semiconductor switching element 110 and the second semiconductor switching element 120 are arranged on the carrier element 106. The carrier element 106 is, for example, plate-shaped or planar and is made of a thermally highly conductive material with low thermal resistance, particularly expediently of a ceramic material, e.g., aluminum oxide (Al2O3), aluminum nitride (AlN), or silicon nitride (Si3N4). This ceramic carrier element 106 also serves to electrically insulate the two semiconductor switching elements 110 and 120 from one another. On a rear side of the carrier element 106 facing away from the semiconductor switching elements 110, 120, a layer 105 of thermally highly conductive material is applied, in particular a copper layer 105, which serves for heat conduction and heat propagation.

[0046] In Fig. 2c, the support element 106 of the half-bridge unit 100 is shown schematically. Fig. 2c shows a plan view of the top side of the carrier element 106, on which the semiconductor switching elements 110 and 120 are arranged. First sections 107 of the top side of the ceramic carrier element 106, on which the semiconductor switching elements 110 and 120 rest, are metallized sections, e.g., metallized with silver. A second section 108 of the top side of the ceramic carrier element 106, on which none of the semiconductor switching elements 110, 120 rests, is not metallized. The first sections 107 made of metallized ceramic can facilitate soldering of the lead frame of the respective semiconductor switching element.

[0047] Each half-bridge unit 100 is present as a separate assembly prior to assembly or arrangement in the half-bridge switch arrangement or is structurally separated prior to assembly. A plurality of such half-bridge units 100 can be arranged on a heat sink of the half-bridge switch arrangement, as described below with reference to Fig. 3 will be explained.

[0048] In Fig. 3a, such a heat sink for a half-bridge switch arrangement according to an embodiment of the invention is schematically shown and designated by 180.

[0049] As in Fig. 3a, a plurality of half-bridge units 100 are to be arranged on this heat sink 180. For this purpose, an adhesion layer 181 can be provided to bond the half-bridge units 100 to the heat sink in a materially bonded manner. Alternatively or additionally, a clamping element 182 can be provided for each of the half-bridge units 100 to press the respective half-bridge unit 100 against the heat sink 180. For example, these individual clamping elements 182 can be made of spring steel or the like and can each be fixed to the heat sink 180 by means of fastening means 183, e.g., screws. Fig. 3b and Fig. 3c shows the heat sink 180 and the half-bridge units 100 in assembled state.

[0050] In the example shown, five half-bridge units 100 are shown, so that the half-bridge switch arrangement comprises five parallel-connected half-bridges. However, the number of half-bridge units 100 and thus the number of parallel-connected half-bridges can also be larger or smaller, particularly depending on the desired power or desired total current to flow through the semiconductor switching elements. The half-bridge units 100 represent modular components that can be combined with one another in a structurally simple, flexible, and scalable manner to produce the half-bridge switch arrangement for the inverter phase.

[0051] The individual busbars can be arranged on the arrangement of the heat sink 180 and the half-bridge units 100. According to a first embodiment, the busbars can be designed as components of a common printed circuit board, as will be described below with reference to Fig. 4 will be explained in several views a) to d).

[0052] In Fig. 4a shows an embodiment of a half-bridge switch arrangement according to the invention in a perspective exploded view and is designated by 200. Fig. 4b shows the half-bridge switch assembly 200 in assembled state in a perspective view.

[0053] As in the Fig. 4a and Fig. 4b, the half-bridge switch arrangement 200 has a common circuit board 260 (see Fig. 4c), e.g., as a thick copper circuit board, wherein the first busbar, the second busbar, and the third busbar are each formed as components of this common circuit board 260. The common circuit board 260 is arranged relative to the heat sink 180 such that a main extension plane of the common circuit board 260 is oriented (at least substantially) perpendicular to a respective main extension plane of the individual half-bridge units 100.

[0054] The common circuit board 260 is arranged, for example, on a side of the heat sink that adjoins perpendicularly to its first side, on which the half-bridge units 100 are arranged. The common circuit board 260 can be mechanically connected to the heat sink 180 on this side by means of fastening means 264, such as screws.

[0055] An electrical heat sink insulation layer 290 is arranged between the heat sink 180 and the common circuit board 260, by which the heat sink 180 and the common circuit board 260 are electrically insulated from each other. This heat sink insulation layer 290 can be made of a highly thermally conductive material with low thermal resistance, so that heat can be dissipated from the circuit board 260 to the heat sink 180.

[0056] The half-bridge switch arrangement 200 further comprises a plurality of capacitor units 250, each arranged on a (second) side of the heat sink 180 facing away from the plurality of half-bridge units 100. Each of these capacitor units 250 has at least one discrete capacitor element. These capacitor units 250, or their individual capacitor elements, each represent, in particular, intermediate circuit capacitors. For example, each of the capacitor units 250 can provide primary intermediate circuit capacitors and / or secondary or distributed intermediate circuit capacitors.

[0057] In the example shown, five parallel-connected DC capacitors are provided as capacitor units, but the number of capacitor elements can also be fewer or larger. The size of the DC link can depend on several factors, e.g., the output current or power of the inverter, the variation in the modulation index, the required voltage ripple, and the ripple current carrying capacity of the individual capacitors. The number of capacitor units can be changed depending on the application. The half-bridge switch arrangement 200 offers flexibility for scaling the DC link at different power levels. The number of capacitor units can differ from the number of half-bridges. The capacitor units are located very close to the half-bridges, which reduces the inductance of the commutation loop. The capacitor units 250 can be cooled by the heat sink 180.Furthermore, the capacitor units 250 can be cooled by thermal contact with the housing of the inverter via a surface material or a filler, which further improves the cooling of the intermediate circuit.

[0058] The common circuit board 260 has electrical connections 261, 262, 263. A first electrical connection 261 can be provided, for example, to electrically connect the positive power rail to a positive DC voltage connection. A second connection 262 can be provided, for example, to electrically connect the negative power rail to a negative DC voltage connection. Third connections 263 can be provided, for example, to electrically connect the output phase power rail to one or more AC voltage connections.

[0059] For example, the common circuit board 260 may be as shown in Fig. 4c, one layer or ply as the positive busbar 230, two layers as the negative busbar 240, and three layers as the output phase busbar 270. These individual layers or busbars 230, 240, 270 are each plate-shaped or planar and arranged parallel to one another in the common circuit board 260. The number and thickness of the individual layers can be selected, for example, depending on the currents flowing through the respective busbar.

[0060] The busbars 230, 240, and 270 are thus arranged close to one another, which allows for the reduction or minimization of inductive resistance. In particular, this allows for low DC link inductance and a low total inductance of the commutation loop. Due to the short distances between the terminals of the switching elements 110, 120 and the busbars 230, 240, and 270, the commutation loop can be optimized.

[0061] Fig. 4d shows the individual layers or busbars 230, 240, 270 of the common circuit board 260 separately from each other in a schematic plan view.

[0062] For example, the positive busbar 230 may have a plurality of first contact elements 231, each for electrical connection to a respective drain terminal of the individual first semiconductor switching elements 110. Furthermore, the positive busbar 230 may have a plurality of second contact elements 232 for electrical connection to the capacitor units 250 and one or more third contact elements 233 for electrical connection to the first terminal 261 of the common circuit board 260.

[0063] For example, each of the negative busbar layers 240 may each have a plurality of first contact elements 241, each for electrical connection to a respective source terminal of the individual second semiconductor switching elements 120. Furthermore, the negative busbar 240 may have a plurality of second contact elements 242 for electrical connection to the capacitor units 250 and one or more third contact elements 243 for electrical connection to the second terminal 262 of the circuit board 260.

[0064] For example, each of the output phase busbar layers 270 may each have a plurality of first contact elements 271 for electrically connecting to a respective source terminal of the individual first semiconductor switching elements 110, as well as a plurality of second contact elements 272 for electrically connecting to a respective drain terminal of the individual second semiconductor switching elements 120. Furthermore, the output phase busbar layers 270 may have one or more (here, two) third contact elements 273 for electrically connecting to the third terminals 263 of the circuit board 260.

[0065] According to an alternative embodiment of the invention, the busbars can also be provided as individual, separately installed elements and not as components of a common printed circuit board, as will be explained below with reference to Fig. 5 will be explained in different views a) to f).

[0066] In Fig. 5a shows an embodiment of a half-bridge switch arrangement according to the invention in a perspective exploded view and is designated by 300. Fig. 5b shows the half-bridge switch assembly 300 in assembled state in a perspective view.

[0067] The half-bridge switch arrangement 300 also has a plurality of capacitor units 350, each of which is arranged on a second side of the heat sink 180 facing away from the plurality of half-bridge units 100.

[0068] The positive busbar 330, the negative busbar 340 and the output phase busbar 370 are each plate-shaped and arranged relative to the heat sink 180 such that a respective main extension plane of these busbars 330, 340 and 370 is each oriented (at least substantially) parallel to a respective main extension plane of the individual half-bridge units 100.

[0069] For example, the positive busbar 330 and the negative busbar 340 are arranged parallel to each other on a side of the capacitor units 350 facing away from the heat sink 180. The output phase busbar 370 is arranged, for example, on a side of the plurality of half-bridge units 100 facing away from the heat sink 180. The output phase busbar 370 is thus spaced further apart from the heat sink 180 and a housing of the half-bridge switch arrangement 300 than the positive and negative busbars 330, 340, thereby reducing the output common-mode capacitance.

[0070] Between the positive busbar 330 and the negative busbar 340, an electrical busbar insulation layer 395 is arranged parallel to these rails, by which these two busbars 330, 340 are electrically insulated from each other.

[0071] For example, two first holding elements 305 are provided for securing the output phase busbar 370. Furthermore, two second holding elements 306 are provided for securing the positive busbar 330, the negative busbar 340, and the busbar insulating layer 395.

[0072] The half-bridge switch arrangement 300 further comprises a printed circuit board 360, which is arranged relative to the heat sink 180 such that a main extension plane of the printed circuit board 360 is oriented (at least substantially) perpendicular to a respective main extension plane of the individual half-bridge units 100 and further perpendicular to the respective main extension plane of the positive busbar 330, the negative busbar 340, and the output phase busbar 370. The printed circuit board 360 is arranged, for example, on a side of the heat sink that adjoins perpendicularly to its first side, on which the half-bridge units 100 are arranged. The printed circuit board 360 can be mechanically connected to the heat sink 180 on this side, for example, by means of fastening means 364 such as screws.

[0073] An electrical heat sink insulation layer 391 is provided between the heat sink 180 and the circuit board 360, which electrically insulates the heat sink 180 and the circuit board 360 from each other. Furthermore, a layer 390 is provided between the heat sink 180 and the circuit board 360 as a spacer or gap filler. The heat sink insulation layer 391 and the layer 390 are each made, in particular, of a material with good thermal conductivity and low thermal resistance in order to dissipate heat from the circuit board 360 to the heat sink 180.

[0074] Furthermore, a plurality of decoupling capacitors 361 are arranged on a side of the circuit board 360 facing away from the heat sink 180 to reduce the inductance of the commutation loop. For example, these decoupling capacitors 361 can each be formed as a ceramic multilayer capacitor.

[0075] Furthermore, a booster stage 362 may be provided on the circuit board 360 for each of the semiconductor switching elements 110, 120 to reduce adverse effects of an unequal distance between a main gate driver or main gate drivers and the gate terminal of each switching element.

[0076] The output phase busbar 370 has a plurality of contact elements 371 for electrical connection to the circuit board 360. For example, these contact elements 371 can each be fork-shaped or Y-shaped and extend from the plate-shaped busbar 370 toward the circuit board 360, where they can be integrally connected to the circuit board, in particular by a soldered or sintered connection.

[0077] Fig. 5c shows the arrangement of the positive bus bar 330, the negative bus bar 340, the bus bar insulating layer 395 and the second holding elements 306 in a perspective exploded view. Fig. Figure 5d shows this arrangement in assembled state in a perspective view.

[0078] As in Fig. 5c and Fig. As shown in Figure 5d, the positive bus bar 330 and the negative bus bar 340, corresponding to the output phase bus bar 370, each have a plurality of, for example, fork-shaped or Y-shaped contact elements 331 and 341, respectively, for electrical connection to the circuit board 360.

[0079] The circuit board may have a plurality of layers, with one or more of these layers each being provided for supplying current to the positive busbar 330, the negative busbar 340, and the output phase busbar 370. The individual contact elements 331, 341, and 371 of the individual busbars 330, 340, and 370 are expediently electrically connected to the corresponding circuit board layer(s), in particular by a soldered or sintered connection.

[0080] In Fig. 5e, two such layers 365, 367 of the circuit board 360 are shown separately from each other in a schematic plan view.

[0081] As in Fig. As shown in Figure 5e, the circuit board or the individual layers 365, 367 of the circuit board 360 can each have a plurality of recesses 366 and 368, respectively, e.g., in the form of slots. These slots 366 and 368 are provided to achieve a uniform distribution of current flow through the circuit board 360 and through the individual first and second semiconductor switching elements 110, 120.

[0082] The number and position of these slots per circuit board layer can be determined, for example, by means of measurements and by means of an optimization algorithm, e.g. in the course of a development, manufacturing or commissioning process of the half-bridge switch arrangement 300, as described below with reference to Fig. 6 is explained.

[0083] In Fig. 6 is a part of an embodiment of a half-bridge switch arrangement according to the invention corresponding to Fig. 1 is shown schematically as an electrical circuit diagram and designated 600.

[0084] According to the Fig. 1, the half-bridge switch assembly 600 also includes a positive DC terminal 603, a negative DC terminal 604, and an AC terminal 602, as well as a positive power rail 630, a negative power rail 640, and an output phase power rail 670.

[0085] Furthermore, a plurality n of parallel-connected half-bridges 605 is provided, wherein the individual first semiconductor switching elements or the high-side switching elements 610 are each connected to T H1 , T H2 , T H3 , ..., T Hn are designated, and the individual second semiconductor switching elements or the low-side switching elements 620 are each designated T L1 , T L2 , T L3 , ..., T Ln .

[0086] An impedance between the individual parallel-connected half-bridges 605 in the positive current rail 630 is denoted by Z 11 , Z 12 , Z 13 , ..., Z 1n An impedance between the individual parallel-connected half-bridges 605 in the output phase busbar 670 is denoted by Z 21 , Z 22 , Z 23 , ..., Z 2n An impedance between the individual parallel-connected half-bridges 605 in the negative current rail 640 is denoted by Z 31 , Z 32 , Z 33 , ..., Z 3n designated.

[0087] The output current is in Fig. 6 is shown with the solid lines I1 and I2 respectively when it is positive, and with the dashed lines I3 and I4 respectively when it is negative.

[0088] The line I2 represents the current path from the input to the output when the current is positive and the switching element T H1turns on first. Line I1 represents the current path when T Hn turns on faster. The impedance through which the current flows should be the same in both cases, ie Z 1m =Z 2m for m ∈ (1, 2, ..., n) to ensure that the current is distributed evenly across the scenarios mentioned.

[0089] Accordingly, the line I4 represents the current path when the current is negative and the switching element T L1 turns on first, and line I3 represents the current path when T Ln switches on faster. The negative current should also be evenly distributed and there should be Z 2m =Z 3m for m ∈ (1, 2, ..., n).

[0090] In particular, the following general rule should apply: Z 1m =Z 2m =Z 3m for m ∈ (1, 2, ..., n) to ensure that Z THq =Z THm and Z TLq =Z TLmfor q ∈ (1, 2, ..., n) and m ∈ (1, 2, ..., n).

[0091] To meet this condition Z 1m =Z 2m =Z 3m To fulfill the requirement for m ∈ (1, 2, ..., n), the corresponding slots 366 and 368 are provided in the layers of the circuit board. Using a corresponding algorithm, the size and position of the individual slots can be determined. List of reference symbols 1 half-bridge switch arrangement 2 AC voltage connection 3 DC voltage connection 4 DC voltage connection 5 Half Bridge 10 high-side switches 11 first semiconductor switching elements 20 low-side switches 21 second semiconductor switching elements 30 positive busbar 40 negative power rail 50 primary intermediate circuit 51 first intermediate circuit capacitor 50' second intermediate circuit 51' second intermediate circuit capacitor 70 Output phase busbar 100 half-bridge units 105 copper layer 106 support element 107 metallized sections of the top of the support element 108 non-metallized section of the top side of the support element 110 first semiconductor switching element 120 second semiconductor switching element 180 heat sinks 181 Adhesive layer 182 clamping element 183 Fasteners, screw 200 half-bridge switch arrangement 230 first busbar, positive busbar 231 Contact element 232 contact element 233 Contact element 240 third busbar, negative busbar 241 Contact element 242 contact element 243 Contact element 250 capacitor unit 260 common circuit board 261 electrical connection 262 electrical connection 263 electrical connection 264 Fasteners, screw 270 second busbar, output phase busbar 271 contact element 272 contact element 273 Contact element 290 electrical heat sink insulation layer 300 half-bridge switch arrangement 305 first holding element 306 second holding element 330 first busbar, positive busbar 331 contact element 340 third busbar, negative busbar 341 contact element 350 capacitor unit 360 circuit board 361 Decoupling capacitor 362 Booster Level 364 Fasteners, screw 365 PCB layers 366 recess, slot 367 PCB layer 368 recess, slot 370 second busbar, output phase busbar 371 contact element 390 layer as spacer or gap filler 391 electrical heat sink insulation layer 395 electrical busbar insulation layer 602 AC voltage connection 603 DC voltage connection 604 DC voltage connection 605 Half Bridge 610 first semiconductor switching elements, high-side switching elements 620 second semiconductor switching elements, low-side switching elements 630 positive busbar 640 negative busbar 670 Output phase busbar

Claims

[1] Half-bridge switch arrangement (1, 200, 300) with a plurality of parallel-connected half-bridges (5), each half-bridge (5) having a first semiconductor switching element (11, 110) and a second semiconductor switching element (21, 120), comprising: a plurality of half-bridge units (100), each half-bridge unit comprising one of the first semiconductor switching elements (11, 110), one of the second semiconductor switching elements (21, 120) and a carrier element (106), the respective first semiconductor switching element (11, 110) and the respective second semiconductor switching element (21, 120) being arranged on the respective carrier element (106), each half-bridge unit (100) being present as a separate assembly prior to being arranged in the half-bridge switch arrangement (1, 200, 300), a heat sink (180), wherein the plurality of half-bridge units (100) are in thermal contact with the heat sink (180), a first busbar (30, 230, 330), to which a first terminal of each of the individual first semiconductor switching elements (11, 110) of the plurality of half-bridge units (100) is electrically connected, a second busbar (70, 270, 370), to which a second terminal of each of the individual first semiconductor switching elements (11, 110) of the plurality of half-bridge units (100) and a first terminal of each of the individual second semiconductor switching elements (21, 120) of the plurality of half-bridge units (100) are electrically connected, a third busbar (40, 240, 340), to which a second terminal of each of the individual second semiconductor switching elements (21, 120) of the plurality of half-bridge units (100) is electrically connected. [2] Half-bridge switch arrangement (1, 200, 300) according to claim 1, further comprising at least one adhesion layer (181) which is arranged between the heat sink (180) and the individual half-bridge units (100), and / or further comprising at least one clamping element (182) which presses at least one of the half-bridge units (100) against the heat sink (180). [3] Half-bridge switch arrangement (1, 200, 300) according to claim 1 or 2, wherein the respective carrier element (106) of each half-bridge unit (100) is made of a ceramic material. [4] Half-bridge switch arrangement (1, 200, 300) according to claim 3, wherein first sections (107) of an upper side of the respective carrier element (106) of each half-bridge unit (100), on which the respective first semiconductor switching element (11, 110) and the respective second semiconductor switching element (21, 120) rest, are each metallized. [5] Half-bridge switch arrangement (1, 200, 300) according to claim 4, wherein a second portion (108) of the upper side of the respective carrier element (106) of each half-bridge unit (100), on which the respective first semiconductor switching element (11, 110) and the respective second semiconductor switching element (21, 120) do not rest, is not metallized. [6] Half-bridge switch arrangement according to one of the preceding claims, further comprising at least one capacitor unit (50, 250, 350) each comprising at least one capacitor element, wherein the at least one capacitor unit (50, 250, 350) is arranged on a side of the heat sink (180) facing away from the plurality of half-bridge units (100). [7] Half-bridge switch arrangement (1, 300) according to one of the preceding claims, further comprising a printed circuit board (360), wherein at least one recess (366, 368) is provided in the printed circuit board (360) or in individual or multiple layers (365, 367) of the printed circuit board (360) for a uniform distribution of a current flow through the printed circuit board (360) and through the individual first semiconductor switching elements (110) and the individual second semiconductor switching elements (120). [8] Half-bridge switch arrangement (1, 200) according to one of the preceding claims, further comprising a common circuit board (260), wherein the first busbar (230), the second busbar (270) and the third busbar (240) are each formed as individual components of the common circuit board (260), and wherein the common circuit board (260) is arranged relative to the heat sink (180) such that a main extension plane of the common circuit board (260) is oriented perpendicularly or at least substantially perpendicularly to a respective main extension plane of the individual half-bridge units (100). [9] Half-bridge switch arrangement (1, 200) according to claim 8, further comprising at least one electrical heat sink insulation layer (290) by which the heat sink (180) and the common circuit board (260) are electrically insulated from each other. [10] Half-bridge switch arrangement (1, 300) according to one of claims 1 to 7, wherein the first busbar (330), the second busbar (370) and the third busbar (340) are each plate-shaped and are arranged relative to the heat sink (180) such that a respective main extension plane of the first busbar (330), the second busbar (370) and the third busbar (340) is each oriented parallel or at least substantially parallel to a respective main extension plane of the individual half-bridge units (100). [11] Half-bridge switch arrangement (1, 300) according to claim 10, wherein one, several or all of the first busbar (330), the second busbar (370) and the third busbar (340) are arranged on a side of the heat sink (180) facing away from the plurality of half-bridge units (100), in particular on a side of the at least one capacitor unit (350) facing away from the heat sink (180), and / or wherein one, several or all of the first busbar (330), the second busbar (370) and the third busbar (340) are arranged on a side of the plurality of half-bridge units (100) facing away from the heat sink (180), [12] Half-bridge switch arrangement (1, 300) according to claim 11, wherein the first busbar (330) and the third busbar (340) are arranged parallel to one another on the side of the heat sink (180) facing away from the plurality of half-bridge units (100), in particular on the side of the at least one capacitor unit (350) facing away from the heat sink (180), and wherein the second busbar (370) is arranged on the side of the plurality of half-bridge units (100) facing away from the heat sink (180). [13] Half-bridge switch arrangement (1, 300) according to one of claims 10 to 12, further comprising a printed circuit board (360), wherein the printed circuit board (360) is arranged relative to the heat sink (180) such that a main extension plane of the printed circuit board (360) is oriented perpendicularly or at least substantially perpendicularly to a respective main extension plane of the individual half-bridge units (100). [14] Half-bridge switch arrangement (1, 300) according to claim 13, wherein the first busbar (330), the second busbar (370) and the third busbar (340) each have at least one, in particular fork-shaped or Y-shaped, contact element for electrical connection to the circuit board. [15] Half-bridge switch arrangement (1, 300) according to claim 13 or 14, further comprising at least one electrical heat sink insulation layer (391) by which the heat sink (180) and the circuit board (360) are electrically insulated from one another.

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