Power module and electronic system comprising such a module

Abstract

The present invention relates to a power module (1) configured to be used with an electronic device (2), the power module comprising a control circuit (3), at least one electrical control pin (4) electrically connected to the control circuit, and at least one connection pad (5) located in line with the control circuit, in particular in line with a central zone of this control circuit, configured to allow the electrical connection between the electrical control pin and the control circuit, this connection pad being configured so that this connection of the electrical control pin can be carried out with a positioning margin chosen to compensate for the internal and external dispersions.

Description

Power module and electronic system comprising such a module

[0001] The present invention relates to a power module, in particular a power module for 800V traction inverters

[0002] It is known to use a power module implementing a switching arm with a high-side switch formed of several transistors, called high-side, and a low-side switch also formed of several transistors, called low-side. Generally, the transistors on each side are distributed in two parallel rows. The power module further comprises a control circuit with two parts, distant from each other, for controlling respectively the high-side transistors and the low-side transistors. Each of the two parts comprises electrical control pins projecting upwards or downwards to be connected to a control device, in particular an inverter.

[0003] To manage the electrical connection of the control circuit between the power module's control circuit and the inverter's electronic board, the electrical control pins must be as straight as possible and located on top of the control circuit. They are usually assembled using sleeves soldered onto the power module.

[0004] A common problem when assembling the power module into the inverter is mechanical dispersions that come from the internal assembly of the power module and the connection of the power module to a heat sink:

[0005] the electrical control pins have placement dispersions compared to the power module reference

[0006] the power module has dispersions in its placement compared to the heat sink references.

[0007] the electronic control pin is inserted into a sleeve whose 2 ends are not perfectly aligned

[0008] the sleeve is soldered to a control circuit with an angle and offset resulting from the assembly process.

[0009] The control circuit is soldered onto a power circuit with an angle and offset due to the assembly process.

[0010] electrical connectors are laser welded onto the power circuit with additional dispersions

[0011] an epoxy resin molded component surrounds the power module with molding dispersions

[0012] the power module is fixed on a heat sink with assembly dispersions

[0013] The inverter's electronic board is positioned opposite the heat sink with other assembly dispersions.

[0014]

[0015] When all these variations are added up, it becomes clear that in some cases the control electronic pins cannot be inserted into the inverter's electronic board.

[0016] The invention aims to solve these drawbacks.

[0017] A power module configured for use with an electronic device (e.g., an inverter) is provided, the power module comprising:

[0018] a control circuit,

[0019] at least one electrical control pin electrically connected to the control circuit

[0020] at least one connection pad located at the right of the control circuit, in particular at the right of a central zone of this control circuit, configured to allow the electrical connection between the electrical control pin and the control circuit, this connection pad being configured so that this connection of the electrical control pin can be made with a positioning margin chosen to compensate for internal dispersions (for example: positioning dispersion of the internal components of the power module) and external dispersions (for example: positioning dispersions between the power module and components external to this power module, in particular a heat sink and an electronic card).

[0021] Thus, the use of connection pads increases the tolerance of the assembly to existing dispersions.

[0022] According to one aspect of the invention, the power module comprises a power circuit.

[0023] According to one aspect of the invention, the control circuit of the power module is soldered onto the power circuit.

[0024] Alternatively, the power module control circuit is glued to the power module.

[0025] Alternatively, the power module control circuit is sintered onto the power module.

[0026] According to one aspect of the invention, the power module comprises electrical connectors soldered to the power circuit.

[0027] According to one aspect of the invention, the electrical connectors are copper plates electrically connected to the power circuit.

[0028] According to one aspect of the invention, the electrical connectors are rectangular in shape, and extend beyond the surface of the power circuit.

[0029] According to one aspect of the invention, the power module comprises at least 3 electrical connectors: an electrical connector connected to the positive edge, an electrical connector connected to the negative terminal, and an electrical connector connected to the phase.

[0030] According to one aspect of the invention, the power module comprises a holding component, in particular made of epoxy resin, overmolding the power circuit and / or the control circuit and / or the electrical connectors.

[0031] According to one aspect of the invention, the connection pad has a surface area 6 times larger than the cross-section of the electrical control pin.

[0032] According to one aspect of the invention, the connection area has a circular, or oval or polygonal circumference with a characteristic dimension such that the diameter or the largest side or the diagonal is at least 2 mm, in particular at least 3 mm.

[0033] According to one aspect of the invention, the connection pad is a planar face.

[0034] According to one aspect of the invention, the connection pad is formed by a block of electrically conductive material, for example metal, in particular a copper alloy.

[0035] According to one aspect of the invention, the connection pad is arranged in the bottom of a cavity of the power module.

[0036] According to one aspect of the invention, the cavity is formed by hollowing out (by laser for example) the holding component overmolded on the power module.

[0037] According to one aspect of the invention, the electrical control pin penetrates the cavity to be brought into contact with the connection pad.

[0038] Thus, the use of a connection pad advantageously makes it possible to increase the tolerance to dispersions during assembly.

[0039] According to another embodiment of the invention, the lower end of at least one electrical control pin comprises a connection pad.

[0040] According to one aspect of the invention, the connection pad in this embodiment has an area at least 10 times larger than the section of the electrical control pin.

[0041] According to one aspect of the invention, the power module comprises a vertical conductive column, electrically connected to the control circuit.

[0042] According to one aspect of the invention, the upper face of the power module comprises an insulating layer.

[0043] According to one aspect of the invention, the insulating layer of the power module has a thickness enabling the power module to be electrically insulated, in particular a thickness greater than 0.1 mm.

[0044] According to one aspect of the invention, the insulating layer, for example, has a thickness of between 0.5 and 1.5 mm, in particular between 0.8 and 1.2 mm, in particular 1 mm.

[0045] According to one aspect of the invention, a portion of the insulating layer is removed by laser at the position of the conductive column.

[0046] According to one aspect of the invention, the conductive column of the power module passes through the insulating layer on the upper face of the power module.

[0047] According to one aspect of the invention, the conductive column protrudes beyond the upper surface of the power module. In particular, the end of the conductive column is raised relative to the upper surface by a distance greater than 0.1 mm.

[0048] According to one aspect of the invention, the conductive column is raised relative to the upper surface of the power module by a distance of between 0.2 and 0.5 mm, in particular by a distance of 0.3 mm.

[0049] According to one aspect of the invention, the connection pad has a surface area at least 6 times larger than the cross-section of the conductive column.

[0050] According to one aspect of the invention, the connection pad of the electrical control pin is arranged to be placed in contact with the conductive column and ensures electrical contact between the electrical control pin and the control circuit.

[0051] Advantageously, this embodiment does not require a step of digging the holding part.

[0052] Advantageously, the electrical connection surface on the control circuit is the contact surface with the conductive column. In particular, this connection surface is much smaller than the surface of the connection pad. This allows less connection surface to be used on the control circuit.

[0053] According to one embodiment of the invention, the power module comprises a connector carrying a plurality of electrical pins for controlling the power module.

[0054] According to one aspect of the invention, the invention makes it possible, thanks to this grouping of the control pins within a connector, to obtain greater robustness of the assembly while allowing precise positioning of the control pins.

[0055] According to one aspect of the invention, the connector is formed by overmolding the control pins.

[0056] Alternatively, the connector has holes for inserting pins into the connector.

[0057] According to one aspect of the invention, the connector comprises a holding body, and positioning legs.

[0058] According to one aspect of the invention, the connector is made of electrically insulating material.

[0059] According to one aspect of the invention, the electrical control pins may be angled, and connect the connection points of the control circuit to the retaining body of the connector.

[0060] According to one aspect of the invention, it is possible to use a connector regardless of the component that has a connection pad. In particular, it is possible to use a connector carrying the electrical control pins if the connection pad is at the end of the electrical control pins, or if the connection pad is made in a cavity of the power module.

[0061] According to one embodiment of the invention, the power module comprises one or more positioning members.

[0062] According to one aspect of the invention, the connector comprises a set of positioning legs, in particular as many positioning legs as the power module comprises positioning members, in particular two positioning legs.

[0063] According to one aspect of the invention, the connector comprises fixing members allowing its fixing with a reference positioning with positioning members of the power module.

[0064] According to one aspect of the invention, the connector fixing members are the connector positioning legs. The positioning legs then make it possible both to position the connector precisely on the power module and to ensure mechanical fixing.

[0065] According to one aspect of the invention, the positioning members of the power module are positioning holes configured for positioning legs of a rigid connector.

[0066] According to one aspect of the invention, the positioning members are placed on "lost connectors", that is to say copper connectors made in the same way as the electrical connectors soldered on the power module, but not electrically connected to the power circuit.

[0067] Thus, these lost connectors only play a role of positioning and mechanical maintenance, and have no role of electrical connection.

[0068] According to one aspect of the invention, the lost connectors are copper rectangles positioned on the upper face of the power module, and extending beyond the surface of the power module.

[0069] According to one aspect of the invention, the lost connectors may comprise one or more positioning orifices allowing the passage of a fixing member such as a bolt, or the centering pin of a tool.

[0070] In this case, the positioning holes of the lost connectors allow the power module to be mechanically held in place.

[0071] According to one aspect of the invention, the positioning holes also serve as a known reference position for accurately determining the locations in the power module control circuit to which the electrical control pins are to be connected.

[0072] According to one aspect of the invention, the power module comprises two lost connectors, each lost connector comprising a positioning hole.

[0073] According to one aspect of the invention, a lost connector comprises a round-shaped positioning orifice, called a "centering orifice".

[0074] According to one aspect of the invention, a lost connector comprises an oblong-shaped positioning orifice, called a "placement orifice".

[0075] According to one aspect of the invention, the combination of the round and oblong shaped positioning holes allows isostatic positioning of the power module.

[0076] Advantageously, the use of positioning holes placed directly on the power module makes it possible to limit uncertainties when connecting the electrical control pins. This method can be used alone, or in addition to the use of connection pads to compensate for existing uncertainties.

[0077] According to one aspect of the invention, the connector thus advantageously makes it possible to precisely position all of the electrical control pins relative to the positioning holes made in the lost connectors.

[0078] According to one aspect of the invention, the connector advantageously makes it possible to mechanically hold all of the electrical control pins, and thus to prevent their deterioration during storage or transport.

[0079] According to one aspect of the invention, the connector also makes it easier to connect the electrical control pins to the power module because all of the electrical control pins are connected simultaneously.

[0080] According to one aspect of the invention, the lost connectors are positioned on an edge of the power module.

[0081] Notably, all lost connectors are positioned on the same edge as one or more of the electrical connectors.

[0082] According to another embodiment of the invention, the lost connectors are placed on two opposite edges of the power connector, in particular on edges perpendicular to the edges on which the electrical connectors are placed.

[0083] According to one aspect of the invention, the connector allowing the rigid holding of all the pins has a “U” shape.

[0084] According to one aspect of the invention, the connector holding body has a horizontal rectangular surface on which the connection pins are fixed.

[0085] According to one aspect of the invention, the connector has two positioning legs intended to be introduced into the positioning holes of the lost connectors.

[0086] According to one aspect of the invention, the arrangement of the lost connectors on two opposite edges advantageously allows the use of a simpler connector, therefore less expensive to produce.

[0087] The invention also relates to an electronic system comprising:

[0088] an electronic device,

[0089] a power module electrically connected to the electronic device

[0090] the electronic device being electrically connected to the control circuit of the power module by at least one electronic pin of the power module.

[0091] According to one aspect of the invention, the electronic device comprises a device for controlling the power modules, for example an inverter.

[0092] According to one aspect of the invention, the electronic device comprises an electronic card to which the power module control device is electrically connected, this card being arranged to allow the electrical connection of the power modules to the power module control device.

[0093] According to one aspect of the invention, the electronic system comprises a heat sink.

[0094] According to one aspect of the invention, the power module of the electronic system is attached to the heat sink. For example, the power module is glued, soldered or sintered onto the heat sink.

[0095] According to one aspect of the invention, the heat sink of the electronic system comprises holes for positioning the heat sink.

[0096] According to one aspect of the invention, the connector of the power module which carries the control pins is fixed to the heat sink, in particular thanks to the positioning holes of the heat sink.

[0097] According to one aspect of the invention, the electrical control pins are connected to the electronic device by passing through the vias of the electronic board of the electronic device.

[0098] The invention also relates to a method of assembling an electronic system, the method comprising the following steps:

[0099] Provide an electronic device,

[0100] Assemble a power module by connecting at least one electrical control pin to the control circuit via a conductive column,

[0101] The electrical connection of the electrical control pin to the control circuit being made on at least one connection pad of the power module,

[0102] According to one aspect of the invention, the step of assembling the power module comprises a step of positioning the electrical control pins on the power circuit.

[0103] According to one aspect of the invention, the step of positioning the electrical control pins comprises:

[0104] A step of positioning the electrical control pins relative to positioning members of the power module, in particular positioning members placed on lost connectors of the power module,

[0105] and / or a step of positioning a connector carrying the electrical power pins on positioning holes placed on lost connectors of the power module,

[0106] and / or a step of positioning a connector carrying the electrical power pins on positioning holes placed on a heat sink.

[0107]

[0108] This is a side sectional view of an electronic system according to an embodiment of the invention in which a connection pad is placed in a cavity of the power module.

[0109] This is a side sectional view of an electronic system according to an embodiment of the invention in which a connection pad is placed at the ends of the connection pins, and is in contact with a vertical conductive column.

[0110] This is a side sectional view of an electronic system according to an embodiment of the invention in which several electrical control pins are carried by a connector.

[0111] This is a top view of a power module according to the invention, in which the power module comprises positioning members placed on lost connectors.

[0112] This is a top view of a power module according to the invention, in which several electrical control pins are carried by a connector fixed to lost connectors placed on the same edge of the power module.

[0113] This is a top view of a power module according to the invention, in which several electrical control pins are carried by a connector fixed on lost connectors placed on opposite edges of the power module.

[0114] The represents an electronic system 27, comprising an electronic device 2 and a power module 1 electrically connected by an electrical control pin of the power module.

[0115] The electronic device 2 comprises a device for controlling the power modules 18, for example an inverter. This device for controlling the power modules is placed on an electronic card 19.

[0116] The power module control device 18 is electrically connected to the electronic card 19, this card being arranged to allow the electrical connection of the power module 1 to the power module control device.

[0117] The power module 1 of the electronic system is fixed on a heat sink 20. For example, the power module is glued, soldered or sintered on the heat sink.

[0118] The heat sink 20 of the electronic system 27 has holes for positioning the heat sink 22.

[0119] Power module 1 includes:

[0120] a power circuit 6,

[0121] a control circuit 3 fixed by soldering or gluing on the power circuit

[0122] an electrical connector 7 welded, soldered or sintered on the power circuit,

[0123] a holding component 8, here in epoxy resin, overmolding the power circuit, the control circuit and the electrical connectors,

[0124] an electrical control pin 4 electrically connected to a vertical conductive column 10,

[0125] a vertical conductive column 10 electrically connected to the control circuit,

[0126] a connection pad 5 located at the right of a central zone of the control circuit, obtained by removing epoxy above the column 10 and releasing the copper to make contact with the electrical pin 4 by soldering, ultrasonic welding or laser welding and making the electrical connection between the electrical control pin and the vertical conductive column 10.

[0127] Here, the power module 1 also comprises a “lost connector” 15 comprising a positioning member 13. The lost connectors and the positioning members are described in more detail in the top view figures (figures 4, 5 and 6).

[0128] The electrical connectors 7 are rectangular-shaped copper plates, electrically connected to the power circuit 6 and extending beyond the surface of the power circuit.

[0129] The connection pad 5 is a flat face, formed by a block of electrically conductive metallic material, here a copper alloy. Its largest side is at least 3 mm long and has a surface area 10 times greater than the cross-section of the electrical control pin 4.

[0130] The power module 1 comprises a vertical conductive column 10 electrically connected to the control circuit 3, and electrically connected to the connection pad 5.

[0131] In this embodiment, the connection pad 5 is arranged in the bottom of a cavity 9 formed by a hollowing (by laser for example) of the holding component 8 overmolding the power module 1. The electrical control pin 4 enters the cavity to be brought into contact with the connection pad.

[0132] The represents an electronic system 27 in which the lower end of the electrical control pin 4 has a connection pad 5 integrated into the electrical control pin 10 by bending and cutting the copper constituting the electrical control pin.

[0133] In this embodiment, the power module 1 comprises a vertical conductive column 10 electrically connected to the control circuit 3 which is thinner than in the embodiment with hollowing of the connection pad 5. In particular, the surface area of ​​the connection pad 5 is 6 times larger than the section of the vertical conductive column.

[0134] The upper face of the power module 1 comprises an insulating layer 11, of a thickness allowing the power module to be electrically insulated, here a thickness of 1 mm.

[0135] A portion of the insulating layer 11 is removed by laser at the position of the vertical conductive column 10. The vertical conductive column of the power module 1 passes through the insulating layer on the upper surface of the power module, and its end is raised relative to the upper surface of the power module by a distance of 0.3 mm.

[0136] The connection pad 5 of the electrical control pin 4 is placed in contact with the conductive column 10 and allows electrical contact between the electrical control pin and the control circuit 3.

[0137] Thus, this embodiment does not require a step of digging the holding part 8. This thus advantageously makes it possible not to degrade the reliability of the power module 1. Furthermore, the connection surface on the control circuit 3 is the contact surface with conductive column 10. In particular, this connection surface is much smaller than the surface of the connection pad 5, which makes it possible to save space on the control circuit.

[0138] It represents an electronic system 27 comprising two electrical control pins 4 each comprising a connection pad 5, these electrical control pins being carried by a connector 23.

[0139] The connector 12 is made of electrically insulating material, and is here formed by overmolding the control pins. It is composed of a holding body 17, and positioning legs 23.

[0140] The grouping of the 4 electrical control pins within a 12 connector makes it possible to obtain greater robustness of the assembly while allowing precise positioning of the electrical control pins.

[0141] The connector 12 is here positioned by fixing members 14 on positioning members 13 of the power module 1. The fixing of the connector on the power module will be described in more detail in the top views of the power module (and 6).

[0142] In an embodiment not shown, the connector 12 is fixed to the heat sink 20, in particular thanks to the positioning holes of the heat sink 22.

[0143] In an embodiment not shown, the connector 12 is used in addition to a power module 1 comprising cavities 9 in which connection pads 5 are placed.

[0144] This is a top view of Power Module 1.

[0145] The power module 1 here has four electrical connectors 7.

[0146] The power module 1 also comprises two positioning members 13, serving as a known reference position making it possible to precisely determine the locations of the control circuit 3 of the power module to which the electrical control pins 4 must be connected.

[0147] These positioning members 13 are here positioning orifices 16 allowing the passage of a fixing member such as a bolt, the centering pin of a tool, or the fixing members of a connector (not present in this embodiment).

[0148] These positioning members 13 are placed on “lost connectors” 15, that is to say copper connectors made in the same way as the electrical connectors 7 soldered on the power module, but not electrically connected to the control circuit 3. These lost connectors only play a role of positioning and mechanical maintenance, and have no role of electrical connection.

[0149] The lost connectors 15 are copper rectangles positioned on the upper face of the power module 1. They extend beyond the surface of the power module.

[0150] The two lost connectors 15 are placed on the same edge of the power module 1, and on the same edge as an electrical connector 7.

[0151] Here, the power module 1 comprises two lost connectors 15, each lost connector comprising a positioning orifice 16. One lost connector comprises a round-shaped positioning orifice, called a “centering orifice” 25. The other lost connector comprises an oblong-shaped positioning orifice, called a “placement orifice” 24.

[0152] The combination of the round and oblong positioning holes 16 allows isostatic positioning of the power module 1. The positioning holes of the lost connectors 15 thus allow the power module to be mechanically held in place.

[0153] The use of positioning holes 16 placed directly on the power module 1 thus makes it possible to limit uncertainties when connecting the electrical control pins 4 to the control circuit 3. This method can be used alone, but is used here in addition to connection pads 5 making it possible to compensate for existing uncertainties.

[0154] The connection pads 5 are here produced by digging cavities 9, but one could also choose an embodiment with the connection pads at the ends of the electrical control pins 4.

[0155] This is a top view of a power module 1 with a connector 12 carrying a set of electrical control pins 4. As before, the connector is made of electrically insulating material, and is here formed by overmolding the electrical control pins. It is composed of a holding body 17, and positioning legs 23.

[0156] The retaining body 17 of the connector has a horizontal rectangular surface on which the electrical control pins 4 are fixed.

[0157] The electrical control pins 4 can be bent, and connect the connection points of the control circuit 3 to the holding body of the connector 17.

[0158] The connector 12 comprises two fixing members 14 allowing its fixing with a reference positioning with positioning members 13 of the power module 1.

[0159] Here, the fixing members 14 of the connector 12 are the positioning legs 23 of the connector. The positioning legs then make it possible both to position the connector precisely on the power module 1 and to ensure mechanical fixing.

[0160] The connector 12 has as many positioning legs 23 as the power module has positioning members 13, here two positioning legs

[0161] As previously, the positioning members 13 of the power module are here positioning orifices 16.

[0162] The connector 12 therefore makes it possible to precisely position all of the electrical control pins 4 in relation to the positioning holes 16 made in the lost connectors 15, and to easily connect all of these electrical control pins to the control circuit 3.

[0163] Shows a top view of another embodiment of the invention, in which the lost connectors 15 are placed on two opposite edges of the power module 1, and on edges perpendicular to the edges on which the electrical connectors 7 are placed.

[0164] The arrangement of the lost connectors 15 on two opposite edges advantageously allows the use of a simpler connector 12, the holding body 17 and the positioning legs 23 of which form a “U”.

Claims

Power module (1) configured to be used with an electronic device (2), the power module comprising: a control circuit (3), at least one electrical control pin (4) electrically connected to the control circuit at least one connection pad (5) located at the right of the control circuit, in particular at the right of a central zone of this control circuit, configured to allow the electrical connection between the electrical control pin and the control circuit, this connection pad being configured so that this connection of the electrical control pin can be made with a positioning margin chosen to compensate for the dispersions and external dispersions. Power module (1) according to claim 1, comprising a power circuit (6). Power module (1) according to claim 2, comprising electrical connectors (7) welded onto the power circuit. Power module (1) according to claim 3, wherein electrical connectors (7) are copper plates electrically connected to the power circuit (6). Power module (1) according to one of claims 2 to 4, comprising a holding component (8), in particular made of epoxy resin, overmolding the power circuit (6) and / or the control circuit (3) and / or the electrical connectors (7). Power module (1) according to one of the preceding claims, wherein the connection pad (5) is arranged in the bottom of a cavity (9) of the power module. Power module (1) according to one of claims 1 to 5, wherein the lower end of at least one electrical control pin (4) comprises a connection pad (5). Power module according to (1) one of the preceding claims, comprising at least one vertical conductive column (10), electrically connected to the control circuit (3). Power module (1) according to one of the preceding claims, comprising a connector (12) carrying a plurality of electrical control pins (4) of the power module. Power module (1) according to one of the preceding claims, comprising one or more positioning members (13). Power module (1) according to claims 9 and 10, in which the connector (12) comprises fixing members (14) allowing its fixing with a reference positioning with positioning members (13) of the power module. Power module (1) according to claim 11, wherein the positioning members (13) of the power module are positioning orifices (16) configured for the positioning of the fixing members (14) of the connector (12). Electronic system (27) comprising: an electronic device (2), a power module (1) according to one of the preceding claims, electrically connected to the electronic device, the electronic device being electrically connected to the control circuit of the power module by at least one electronic pin (4) of the power module. Method for assembling an electronic system (27) according to claim 13, the method comprising the following steps:providing an electronic device (2)assembling a power module (1) comprising at least one vertical conductive column (10) electrically connected to the control circuit (3), by connecting at least one electrical control pin (4) to the control circuit (3) via a vertical conductive column (10)the electrical connection of the electrical control pin to the control circuit being made on at least one connection pad (5) of the power modulethe step of assembling the power module comprising a step of positioning the electrical control pins on the control circuit. Assembling method according to claim 14 of an electronic system (27), comprising a power module according to claim 12, the step of positioning the electrical control pins (4) comprising: a step of positioning the electrical control pins relative to positioning members (13) of the power module (1), in particular positioning members placed on lost connectors (15) of the power module, and / or a step of positioning a connector (12) carrying the electrical control pins on positioning orifices (16) placed on lost connectors of the power module, and / or a step of positioning a connector carrying the electrical power pins on positioning orifices of the heat sink (22) of the electronic system.

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