Inverter for a vehicle and method for manufacturing an inverter

Abstract

An inverter (100) for a vehicle has a housing (102) with a cooling channel (104) and a busbar (106) for carrying a DC voltage. The busbar (106) is located adjacent to the cooling channel (104) and is encased in a potting compound (108) together with a temperature sensor. A printed circuit board with an electrical circuit for controlling a function of the inverter (100) is located on the side of the busbar (106) facing away from the cooling channel (104). The terminals of the temperature sensor are electrically connected to the printed circuit board via two conductors, also encased in the potting compound, whose terminals protrude from the potting compound.

Description

[0001] The present invention relates to an inverter for a vehicle and to a method for manufacturing an inverter.

[0002] Inverters used in vehicles contain power transistors that can be cooled using a cooling medium. To measure the temperature of the cooling medium, temperature sensors can be used, for example, screwed to a cooling insert and the inverter housing.

[0003] JP 2011 - 18 847 A discloses an inverter which is arranged in a resin layer located between the cooling channel and the busbar for the purpose of detecting a temperature difference between a cooling channel and a busbar.

[0004] DE 10 2011 084 229 A1 discloses a temperature sensor with a sensor element and a connection device that pushes the sensor element towards a heat source.

[0005] Against this background, the present invention provides an improved inverter for a vehicle and an improved method for manufacturing an inverter according to the main claims. Advantageous embodiments are described in the dependent claims and the following description.

[0006] If an inverter temperature sensor is embedded in a potting compound along with an inverter busbar, no additional steps are required to attach the sensor to the inverter.

[0007] An inverter for a vehicle has the following characteristics: a housing with a cooling channel for passing a cooling medium; a busbar for carrying a DC voltage, wherein the busbar is arranged adjacent to the cooling channel, and wherein the busbar is encased in a potting compound; a temperature sensor embedded in the potting compound; and a printed circuit board with an electrical circuit for controlling a function of the inverter, wherein terminals of the temperature sensor are electrically connected to the printed circuit board.

[0008] The vehicle can be an electrically powered vehicle, such as a passenger car, a truck, or a rail vehicle. The inverter can be designed to convert a direct current (DC) voltage, for example, from a vehicle battery, into an alternating current (AC) voltage, for example, a three-phase AC voltage to drive an electric machine. The inverter can include electronic components, such as power transistors, which heat up during operation, as is known in conventional inverters. Such components can be cooled using a cooling medium. This can be achieved through thermal coupling between a wall of the cooling channel and the components. For example, the components to be cooled can be arranged on the busbar. The busbar can have a plate-shaped section extending over the cooling channel.The potting compound may have been applied to at least one surface of the busbar during an injection molding process. The potting compound may form a cured potting element. The potting compound may be bonded to the busbar by material bonding and / or form-fitting. Mounting structures may be formed using the potting compound, which can be used, for example, to attach the busbar to the housing or to connect the printed circuit board to the potting compound. The temperature sensor may be configured to detect a temperature and provide a temperature signal representing that temperature. The temperature sensor may have been embedded in the potting compound along with the busbar during the injection molding process. The temperature sensor may be located adjacent to the cooling channel to detect the temperature of the cooling medium.The circuit board can be located on the side of the busbar facing away from the cooling channel. The circuit board can include the electrical circuitry for controlling the inverter's function, arranged in a known alternating direction. For example, the inverter's power transistors can be switched using this circuitry. The circuitry can be designed to incorporate a temperature signal provided by the temperature sensor during inverter operation, for example, to prevent overheating. By embedding the temperature sensor in the potting compound, it is secured within the inverter. This eliminates the need for additional clips to hold the sensor cable. Furthermore, it is not necessary to mount the sensor connector on the circuit board during inverter assembly.

[0009] The potting compound can span one side of the busbar facing away from the cooling channel. The potting compound can have a projection extending beyond the busbar. The temperature sensor can be located within this projection. In this way, the temperature sensor can be positioned next to the busbar, so that, for example, one temperature probe of the sensor faces the cooling channel and one terminal of the sensor faces the circuit board. If the inverter has multiple temperature sensors, the potting compound can have a corresponding number of projections extending beyond the busbar. Thus, the temperature sensors can be located in different projections, for example, on opposite sides of the busbar.

[0010] A temperature sensor can be thermally coupled to the cooling channel to measure the temperature of the cooling medium. If multiple temperature sensors are used, they can be thermally coupled to the cooling channel at different positions, for example, to measure the inlet and outlet temperatures of the cooling medium.

[0011] The temperature sensor can be cylindrical in shape. One longitudinal axis of the temperature sensor can be aligned orthogonally to a main plane of the busbar. This allows for easy connection of the temperature sensor's leads.

[0012] The inverter has a first conductor with a first and a second terminal, and a second conductor with a first and a second terminal. The conductors are encased in potting compound. The terminals protrude from the potting compound. The temperature sensor's connecting leads are electrically connected to the first terminals. The second terminals are electrically connected to the circuit board. In this way, the temperature sensor can be electrically connected to the circuit board using the conductors encased in the potting compound.

[0013] The temperature sensor's connecting leads can be welded to the first terminals of the conductors. The second terminals of the conductors can be soldered to the circuit board. This ensures reliable electrical and mechanical contact.

[0014] The inverter can include at least one additional temperature sensor. This additional temperature sensor can also be embedded in the potting compound. The initial temperature sensor and the additional temperature sensor can be located on opposite sides of the busbar. Therefore, two, three, four, or more temperature sensors can be installed.

[0015] The inverter can comprise multiple power transistors. The inverters can be connected to the busbar. For example, at least one terminal of each power transistor can be electrically connected to the busbar, such as by welding or soldering. The power transistors can be located on the side of the busbar facing the cooling channel. This facilitates heat dissipation from the power transistors to the cooling channel.

[0016] A process for manufacturing an inverter for a vehicle includes the following steps: Providing a housing with a cooling channel for passing a cooling medium; Providing a composite component comprising a busbar for carrying a DC voltage and a temperature sensor, wherein the busbar and the temperature sensor are encased in a potting compound; Providing a printed circuit board with an electrical circuit for controlling a function of the inverter; and

[0017] Arrange the composite component and the printed circuit board on the housing, wherein the busbar is arranged adjacent to the cooling channel, and wherein the printed circuit board is arranged on a side of the busbar facing away from the cooling channel, and connect the terminals of the temperature sensor electrically to the electrical circuit.

[0018] In this way, the temperature sensor in particular can be installed without an additional assembly step.

[0019] The process may include a step of overmolding the busbar and temperature sensor with the potting compound.

[0020] Furthermore, a drive system for a vehicle is presented, incorporating an electric motor and a variant of the previously introduced inverter. This combination offers the advantage of optimally implementing all the aforementioned benefits.

[0021] The drive device is suitable, for example, for an electric axle drive. Such an electric axle drive for a vehicle comprises at least one drive device and a transmission unit. Using the transmission unit, torque provided by the drive device can be converted into drive torque for powering at least one wheel of the vehicle. The transmission unit can include a gearbox for reducing the speed of the electric motor and, optionally, a differential.

[0022] Accordingly, a vehicle may include a specified drive device and additionally or alternatively a specified electric axle drive.

[0023] The invention is explained in more detail by way of example with reference to the accompanying drawings. These show: Fig. 1. A representation of an exemplary embodiment of an inverter; Fig. 2 a representation of an exemplary embodiment of a sensor device; Fig. 3 a representation of an exemplary embodiment of the sensor device; Fig. 4 a representation of an embodiment of another sensor device; Fig. 5 a representation of an embodiment of the further sensor device; Fig. 6 a representation of an embodiment of the further sensor device; Fig. 7 a representation of an exemplary embodiment of a sensor; Fig. 8 a flowchart of an exemplary embodiment of a method for manufacturing an inverter; and Fig. 9 a schematic representation of an exemplary embodiment of a vehicle.

[0024] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, without repeating these elements.

[0025] Fig. Figure 1 shows an embodiment of an inverter 100 for a vehicle. For example, the vehicle includes a battery and an electric motor for propelling the vehicle. The inverter 100 is used, for example, to convert a direct current voltage supplied by the battery into an alternating current voltage for operating the electric motor.

[0026] The inverter 100 has a housing 102 with a cooling channel 104 for conveying a cooling medium. A liquid coolant, for example, is used as the cooling medium. Waste heat generated during operation of the inverter 100 can be dissipated via the cooling medium.

[0027] In one embodiment, a busbar 106 spans a cover of the cooling duct 104. The busbar 106 is used to carry a DC voltage. The busbar 106 is, by way of example, formed as a metal plate and has angled edge sections on two opposite sides.

[0028] According to one embodiment, the inverter 100 has a plurality of power transistors which are connected to the busbar 106 and are arranged on a side of the busbar 106 facing the cooling channel 104.

[0029] At least one surface of the busbar 106 facing away from the cooling channel 104 is encased in a potting compound 108. The potting compound 108 forms a layer extending over the busbar 106 and optionally has a plurality of through-openings. Optionally, a plurality of electrical contacts are provided through the potting compound 108. By way of example, a total of nine pairs of electrical contacts are arranged in a row along one length of the busbar 106. Optionally, the potting compound 108 has a plurality of retaining bosses, for example, for mounting a circuit board of the inverter 100. The retaining bosses extend orthogonally from a surface of the potting compound 108 facing away from the busbar 106.

[0030] According to one embodiment, a surface of the busbar 106 facing the cooling channel 104 is also cast into the potting compound 108.

[0031] Optionally, the potting compound 108 has a projection 110 over the busbar 106 on opposite sides, for example with a through-hole for fixing the potting compound 108 to the housing 102.

[0032] At least one temperature sensor is embedded in the potting compound 108. According to the illustrated embodiment, two temperature sensors are embedded, with the temperature sensors arranged on opposite sides of the busbar 106. For example, a first temperature sensor is part of a first sensor assembly 112 and a second temperature sensor is part of a second sensor assembly 114. The first temperature sensor is used, for example, as an inlet temperature sensor and the second temperature sensor as an outlet temperature sensor.

[0033] According to one embodiment, the inverter 100 is designed to convert a direct current, for example from a battery, into alternating current, which is fed, for example, into a three-phase AC motor.

[0034] According to one embodiment, a cooling insert is arranged between the busbar 106 and the cooling channel 104. Between the cooling insert and the busbar 106, power transistors, for example SiC MOSFETs (silicon carbide MOSFETs), are arranged according to one embodiment. These transistors are cooled by a coolant that flows in the cooling channel 104 beneath the cooling insert.

[0035] The circuit board, which according to one embodiment is arranged parallel to the busbar 106 on a side facing the potting compound 108, has according to one embodiment all the power electronic components required for the operation of the inverter 100 and is used as a combined control and driver board.

[0036] According to one embodiment, the busbar 106 is designed as a copper busbar that, for example, conducts the direct current from a capacitor. The busbar 106 is overmolded and, according to one embodiment, connected to the power transistors, for example the MOSFETs, by welding.

[0037] According to one embodiment, the potting compound 108 is directly overmolded with the busbar 106, for example a copper busbar, as a so-called overmold.

[0038] This enables the integration of temperature sensors in a so-called DC overmold. This eliminates the need to screw the sensor to a cooling insert and the housing 102, or to hold a sensor cable with additional clips and mount a connector on the circuit board.

[0039] Fig. Figure 2 shows an embodiment of a first sensor device 112, such as is also found, for example, in Fig. Figure 1 shows the first sensor device 112, which is arranged at an edge of the potting compound 108. The first sensor device 112 has a projection 220 that extends beyond the busbar 106. The projection 220 is formed by the potting compound 108 and includes a receptacle for a first temperature sensor. According to one embodiment, the receptacle is cylindrical and has a longitudinal direction that is orthogonal to a principal direction of extension of the busbar 106. According to one embodiment, the temperature sensor is received by the receptacle such that a temperature probe of the temperature sensor is thermally coupled to the cooling channel to detect the temperature of the cooling medium.

[0040] The first temperature sensor has connecting leads 222, 224 that protrude from the potting compound 108. The temperature sensor can be electrically connected via the connecting leads 222, 224, for example, directly or via other conductors to the circuit board.

[0041] According to one embodiment, the first sensor device 112 comprises a first conductor with a first terminal 230 and a second terminal 232, and a second conductor with a first terminal 234 and a second terminal 236. The conductors, except for terminals 230, 232, 234, and 236, are encased in the potting compound 108. The connecting leads 222 and 224 of the temperature sensor are electrically contacted with the first terminals 230 and 234. For example, the first terminals 230 and 234 are formed as clamps, with each clamp holding the end of one of the connecting leads 222 and 224. The second terminals 232 and 236 are, for example, formed as contact pins, here vertical pins, and can be inserted into through-holes in the circuit board to establish electrical contact between the temperature sensor and an electrical circuit on the circuit board.For example, terminals 230, 232, 234, 236 are aligned orthogonally to a main extension plane of the busbar 106.

[0042] The conductors, like the busbar 106, are thus encapsulated in the potting compound 106. According to one embodiment, the connecting leads 222, 224 of the temperature sensor are welded to the first terminals 230, 234 of the conductors. The second terminals 232, 236 of the conductors can be soldered to the circuit board.

[0043] In such a construction, the sensor is welded to the casing with the wires, which are referred to here as conductors, and the wires are soldered to the circuit board.

[0044] This allows for easy installation. Only a few assembly steps are required, as the sensor is integrated into the DC overmolding and no additional fixings are necessary. Furthermore, the sensor provides accurate readings. The small number of parts required also results in cost savings.

[0045] According to one embodiment, the temperature sensor, as used for example in Fig. As shown in section 7, it is incorporated in extension 220 in such a way that it is in point contact with a cooling channel or a cooling insert, for example, the one in Fig. The inverter shown in section 1 is coming.

[0046] According to one embodiment, a retaining dome 238 is formed adjacent to the first sensor device 112, which can be used, for example, to hold the circuit board.

[0047] Fig. Figure 3 shows an embodiment of the first sensor device 112. This is, for example, a side view of the sensor device shown in the diagram. Fig. 2 described sensor device.

[0048] The extension 220, which incorporates the temperature sensor, extends beyond a thickness of the potting compound 108 embedding the busbar 106. This allows the temperature sensor to come into thermal contact with the cooling channel.

[0049] A circuit board 340 is spaced apart and arranged parallel to the busbar 106, and is placed on the mounting dome 238 by way of example.

[0050] The free ends of the second connections 232, 236 of the conductors are passed through the circuit board 340 and soldered, for example, in through holes of the circuit board 340.

[0051] Fig. Figure 4 shows an embodiment of a second sensor device 114, as is also found, for example, in Fig. Figure 1 shows the second sensor device 114. It is shaped according to the first sensor device described above and is arranged at a further edge of the potting compound 108. The second sensor device 114 has a projection 220 extending beyond the busbar 106. The projection 220 is formed by the potting compound 108 and includes a receptacle for a second temperature sensor.

[0052] The second temperature sensor, like the first temperature sensor, has connecting leads 222 and 224 that protrude from the potting compound 108. The second temperature sensor can be electrically connected via these leads 222 and 224, for example, directly or via other conductors to the circuit board 340.

[0053] According to one embodiment, the second sensor device 114 comprises a first conductor with a first terminal 230 and a second terminal 232, and a second conductor with a first terminal 234 and a second terminal 236. The conductors, except for terminals 230, 232, 234, and 236, are encased in the potting compound 108. The connecting leads 222 and 224 of the second temperature sensor are electrically contacted with the first terminals 230 and 234. For example, the first terminals 230 and 234 are formed as clamps, with each clamp holding the end of one of the connecting leads 222 and 224. The second terminals 232 and 236 are, for example, formed as contact pins, here vertical pins, and can be inserted into through-holes in the circuit board 340 to establish electrical contact between the second temperature sensor and an electrical circuit on the circuit board 340.For example, terminals 230, 232, 234, 236 are aligned orthogonally to a main extension plane of the busbar 106.

[0054] The conductors, like the busbar 106, are thus encapsulated in the potting compound 106. According to one embodiment, the connecting leads 222, 224 of the second temperature sensor are welded to the first terminals 230, 234 of the conductors. The second terminals 232, 236 of the conductors can be soldered to the circuit board 340.

[0055] Fig. Figure 5 shows an embodiment of the second sensor device 114, as already described in Fig. 4 is described. The second sensor device 114 is arranged adjacent to a through-opening 540 of the potting compound 108.

[0056] Fig. Figure 6 shows a side view of an embodiment of the second sensor device 114, as already described in relation to Fig. 4 is described. The connection 230 is shaped as a flag and has a groove extending from a free end of the connection 230, into which a free end of the connecting cable 222 is clamped.

[0057] Fig. Figure 7 shows an embodiment of a temperature sensor 750, as described with reference to the preceding figures. The temperature sensor 750 can be used, for example, for the sensor devices described with reference to the preceding figures.

[0058] The temperature sensor 750 has a cylindrical body. Connecting leads 222 and 224 extend from one end of the body. A temperature sensor is located at the opposite end from the connecting leads 222 and 224.

[0059] During the manufacturing of the inverter, the body of the temperature sensor 750 is overmolded with potting compound.

[0060] Fig. Figure 8 shows a flowchart of an embodiment of a method for manufacturing an inverter, as described with reference to the preceding figures.

[0061] The method comprises step 801 of providing a housing with a cooling channel for conveying a cooling medium, and step 803 of providing a composite component comprising a busbar for carrying a DC voltage and at least one temperature sensor, wherein the busbar and the temperature sensor are encapsulated in a potting compound. Optionally, in step 805, the composite component is manufactured by overmolding or encapsulating the busbar and the at least one temperature sensor with the potting compound. In step 807, a printed circuit board with an electrical circuit for controlling a function of the inverter is provided. In step 809, the composite component and the printed circuit board are mounted on the housing. The busbar is positioned adjacent to the cooling channel. The printed circuit board is mounted on a side of the busbar facing away from the cooling channel.The temperature sensor's terminals are electrically connected to the electrical circuit.

[0062] Fig.Figure 9 shows a schematic representation of a vehicle 900 according to an exemplary embodiment. The vehicle 900 has an electric axle drive with an electric machine 902. Electrical energy for operating the electric machine 902 is provided by a power supply unit 904, for example, a battery. For example, the power supply unit 904 provides a direct current, which is converted into an alternating current, for example, a three-phase alternating current, using an inverter 100, as described by way of example with reference to the preceding figures, and supplied to the electric machine 902. A shaft driven by the electric machine 902 is coupled directly or by means of a transmission unit 906 to at least one wheel 908 of the vehicle 900. Thus, the vehicle 900 can be moved using the electric machine 902.According to one embodiment, the electric axle drive comprises a housing in which the inverter 100, the electric machine 902 and the gearbox 906 are integrated.

[0063] According to one embodiment, the inverter 100, corresponding to known inverters, has a plurality of power transistors 960 which are suitably controlled to convert the direct current into the alternating current. Reference sign 100 inverters 102 cases 104 Cooling channel 106 busbar 108 Potting compound 110 overhang 112 first sensor device 114 second sensor device 220 continuation 222 first connection line 224 second connection line 230 first connection of the first conductor 232 second connection of the first conductor 234 first connection of the second conductor 236 second connection of the second conductor 238 Holding Dome 340 circuit board 540 Through opening 750 temperature sensor Step 801 of providing an enclosure Step 803 of deploying a composite component 805th step of the manufacturing process Step 807 of providing a printed circuit board 809 Step of Arranging 900 vehicles 902 electric machine 904 Energy supply facility 906 Gearbox unit 960 Plural of power transistors

Claims

[1] Inverter (100) for a vehicle (900), wherein the inverter (100) has the following features: a housing (102) with a cooling channel (104) for passing a cooling medium through it; a busbar (106) for carrying a DC voltage, wherein the busbar (106) is arranged adjacent to the cooling channel (104), and wherein the busbar (106) is encased in a potting compound (108); a temperature sensor (750) which is embedded in the potting compound (108); and a printed circuit board (340) with an electrical circuit for controlling a function of the inverter (100), wherein terminals of the temperature sensor (750) are electrically connected to the printed circuit board, characterized bya first conductor with a first connection (230) and a second connection (232), and a second conductor with a first connection (234) and a second connection (236), wherein the conductors are embedded in the potting compound (108), wherein the connections (230, 232, 234, 236) protrude from the potting compound (108), and wherein connecting leads (222, 224) of the temperature sensor (750) are electrically contacted with the first connections (230, 234), and wherein the second connections (232, 236) are electrically contacted with the circuit board (340). [2] Inverter (100) according to claim 1, wherein the potting compound (108) spans a side of the busbar (106) facing away from the cooling channel (104) and has a projection (220) extending beyond the busbar (106), wherein the temperature sensor (750) is arranged in the projection (220). [3] Inverter (100) according to one of the preceding claims, wherein a temperature sensor of the temperature sensor (750) is thermally coupled to the cooling channel (104) to detect a temperature of the cooling medium. [4] Inverter (100) according to one of the preceding claims, wherein the temperature sensor (750) is cylindrical, wherein a longitudinal extension direction of the temperature sensor (750) is aligned orthogonally to a main extension plane of the busbar (106). [5] Inverter (100) according to one of the preceding claims, wherein the connecting leads (222, 224) of the temperature sensor (750) are welded to the first terminals (230, 234) of the conductors, and wherein the second terminals (232, 236) of the conductors are soldered to the circuit board (340). [6] Inverter (100) according to one of the preceding claims, with a further temperature sensor which is cast in the potting compound (108), wherein the temperature sensor (750) and the further temperature sensor are arranged on opposite sides of the busbar (106). [7] Inverter (100) according to one of the preceding claims, comprising a plurality of power transistors (960) connected to the busbar (106) and arranged on a side of the busbar (106) facing the cooling channel (104). [8] Method for manufacturing an inverter (100) for a vehicle (900), the method comprising the following steps: Providing (801) a housing (102) with a cooling channel (104) for passing a cooling medium; Providing (803) a composite component comprising a busbar (106) for carrying a DC voltage and a temperature sensor (750), wherein the busbar (106) and the temperature sensor (750) are encased in a potting compound (108); Providing (807) a printed circuit board (340) with an electrical circuit for controlling a function of the inverter (100); and Arranging (809) the composite component and the printed circuit board (340) on the housing (102), wherein the busbar (106) is arranged adjacent to the cooling channel (104), and wherein the printed circuit board (340) is arranged on a side of the busbar (106) facing away from the cooling channel (104), and connecting terminals of the temperature sensor (750) electrically to the electrical circuit. [9] Method according to claim 8, comprising a step (811) of overmolding the busbar (106) and the temperature sensor (750) with the potting compound (108).

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