Inverter assembly for monitoring a power semiconductor

Abstract

The invention relates to an inverter assembly for monitoring the temperature of a power semiconductor, comprising: at least one semiconductor package having a current connection directed towards the outside of the semiconductor package and at least one connection pin of a signal or control connection directed towards the outside of the semiconductor package; and a circuit board arranged at a distance above the semiconductor package, the at least one coupling pin being guided through a through-hole of the circuit board and fastened to the circuit board; and the temperature sensor is arranged on the circuit board and is close to the at least one connection pin, so that the temperature sensor can measure the temperature transmitted to the connection pin by the power semiconductor arranged in the semiconductor package.

Description

Field of the Invention

[0001] The present invention relates to the field of electric vehicles, in particular to the field of monitoring the temperature of power semiconductors of semiconductor packages, which are installed in the inverters of power electronic modules for operating electric drive devices. Background Art

[0002] The use of electronic modules (such as power electronic modules) in motor vehicles has increased significantly in recent decades. This is due in part to the need to improve fuel economy and vehicle performance, and in part to the progress of semiconductor technology. The main components of such electronic modules, also known as power electronics, are also known as ECUs (electronic control units) and DC / AC inverters (English: Inverter). The electronic control unit is connected to one or more vehicle controllers or is part of a vehicle controller, and obtains control signals and / or information, for example, based on driving behavior or signals from other controllers. The DC / AC inverter is used to power an electric machine such as an electric motor or a generator with a polyphase alternating current (AC). Here, the direct current generated by a DC energy source (such as a battery or a storage battery) is converted into a polyphase alternating current. For this purpose, the inverter consists of a large number of electronic components, such as semiconductor power switches also known as power semiconductors, and a bridge circuit (such as a half-bridge) is implemented using these electronic components.

[0003] Power semiconductors are sensitive to temperature and are therefore cooled via a cooling system. Nevertheless, it is still necessary to monitor the temperature of at least some of the power semiconductors so that measures can be taken in the event of overheating to avoid damage to the entire system. There are various options known for monitoring the temperature of power semiconductors. Here, the temperature monitoring can be directly integrated into the semiconductor package, such as as a temperature sensor or as a sensing diode. The temperature can also be measured directly on the semiconductor package, that is, on the housing (coating part) of the power semiconductor. Here, the measurement can be carried out in contact with the housing or without contact with the housing. Summary of the Invention

[0004] Since many of these solutions are not only expensive but also complex, the object of the present invention is to provide an improved method for measuring the temperature of power semiconductors of semiconductor packages.

[0005] This object is solved by the features of the independent claims. Advantageous designs are the subject matter of the dependent claims.

[0006] An inverter assembly is proposed, which has: at least one semiconductor package having at least one connection pin pointing outside the semiconductor package for current connection and a signal or control connection pointing outside the semiconductor package; and a circuit board arranged at a certain distance above the semiconductor package, wherein at least one connection pin is guided through a through-hole of the circuit board and fastened to the circuit board; and a temperature sensor arranged on the circuit board and close to at least one connection pin, so that the temperature sensor can measure the temperature transferred to the connection pin of the power semiconductor arranged in the semiconductor package.

[0007] In one embodiment, the temperature sensor is arranged on the upper side of the circuit board facing away from the semiconductor package or on the lower side facing the semiconductor package.

[0008] In one embodiment, the temperature sensor is arranged at a certain minimum distance from the connection pin so that the temperature sensor does not touch the connection pin.

[0009] In one embodiment, the temperature sensor is arranged at a predetermined distance from the connection pin, and at least one conductor trace is provided on the circuit board, which is led from the temperature sensor to the connection pin and is used for heat transfer.

[0010] In one embodiment, the temperature sensor is formed as an SMD component.

[0011] In one embodiment, the temperature sensor is in operative connection with an evaluation unit of the inverter, wherein the evaluation unit is configured to process the temperature value measured by the temperature sensor so that the evaluation unit can recognize an exceedance of a predetermined temperature.

[0012] In one embodiment, a plastic component or plastic mixture with a centered opening is provided on the surface of the semiconductor package facing the circuit board, and wherein the temperature sensor is arranged on the circuit board in the area above the opening.

[0013] Furthermore, a power electronics for operating a three-phase electric motor of a vehicle is provided, wherein the power electronics has an inverter assembly and at least one electronic controller, which is connected to the electric motor to control and regulate the electric motor and is connected to the inverter.

[0014] Furthermore, an electric drive device for a vehicle is provided, which has a three-phase electric motor and a battery, and a power electronics connected to both.

[0015] Further features and advantages of the present invention result from the following description of embodiments of the present invention, with the aid of the drawings which show details of the present invention, and from the claims. Each feature can be implemented either individually or in any combination in variants of the present invention. Description of the Drawings

[0016] The preferred embodiments of the present invention are explained in detail below with the aid of the drawings.

[0017] Figure 1 An inverter structure with a temperature sensor arranged according to an embodiment of the present invention is shown;

[0018] Figure 2 An inverter structure with a temperature sensor arranged according to an alternative embodiment of the present invention is shown;

[0019] Figure 3 An inverter structure with a temperature sensor arranged according to an alternative embodiment of the present invention is shown.

[0020] In the following description of the drawings, the same elements or functions are provided with the same reference signs. Detailed Description of the Invention

[0021] The semiconductor package 4 refers to one or more encapsulated (located within a housing) power semiconductors (chips) that are used as high-side switches or low-side switches and include (unencapsulated) connection pins for making electrical or signal contacts. The term semiconductor package 4 is also understood to mean a half-bridge module in which the high-side switch and the low-side switch have been mounted together in a housing.

[0022] The current semiconductor package 4, in addition to its current connection parts (DC and AC), also has at least one signal or control connection part leading to the outside of the semiconductor package 4, which can be, for example, a gate connection part or a Kelvin source connection part. These signal or control connection parts are arranged / fastened inside the semiconductor package 4 close to the power semiconductor (chip). Their connection pins 40, 41 leading from there to the outside are usually contacted with the printed circuit board 2 arranged above the semiconductor package 4 by means of THT (through-hole technology) during assembly, that is, the connection pins are led through the through-holes from the underside of the printed circuit board to the upper side and then fastened there, for example, by soldering.

[0023] As already mentioned at the beginning, it is important to monitor the temperature of the semiconductor package 4 so that measures can be taken to protect the semiconductor package 4, and more precisely the power semiconductor (chip) located therein, in the event of overheating. A temperature sensor is used for temperature monitoring, and the temperature sensor is arranged, for example, near the semiconductor package 4 and measures the temperature there. Since there are some very complex methods for temperature measurement, a simple concept that is both inexpensive and easy to implement in terms of manufacturing is proposed below, especially with an inexpensive temperature sensor.

[0024] It is proposed to use the connection pins 40 or 41 of the signal or control connection already present in the currently used semiconductor package 4 in order to measure the temperature of the power semiconductor (chip) within the semiconductor package 4. Since the connection pins 40 or 41 of the signal or control connection are already arranged near the power semiconductor (chip) and are formed of a heat-conducting material (such as copper), they absorb the heat of the power semiconductor (chip) and transport the heat to the circuit board 2 via their respective connection pins 40 or 41. In this regard, the connection pins 40 or 41 are used for the proposed temperature measurement. In addition, according to the invention, the temperature sensor 3 is arranged on the circuit board 2 as close as possible to the connection pins 40 or 41 but without physical contact therewith, i.e., at a distance D (only drawn in Figure 2 ).

[0025] The temperature sensor 3 can be arranged on the upper side of the circuit board 2 as shown in Figure 1 , or can be arranged on the lower side facing the semiconductor package 4 as shown in Figure 2 . The temperature sensor is preferably formed as an SMD (surface mounted device) because the temperature sensor can be fastened to the circuit board 2 together with other components 20 in the SMT process that is already to be implemented for equipping the circuit board 2.

[0026] In addition, the temperature sensor 3 is also in operative connection with the evaluation unit 1, for example, via conductor traces integrated in the circuit board 2. The evaluation unit 1 can be part of an (external) electronic controller of the power electronics of the vehicle, or can be a separate unit (external or arranged on the circuit board 2) that is in operative connection therewith. The evaluation unit processes the data transmitted from the temperature sensor 3 in order to determine whether the detected temperature is within an allowable range. If this is not the case, i.e., a predetermined temperature is exceeded, the evaluation unit 1 initiates corresponding measures to protect the power semiconductor (chip), i.e., for example, shutting down the inverter. For this purpose, the evaluation unit is in operative connection with the electronic controller of the power electronics.

[0027] In addition, one or more conductor traces can be provided between the connection pins for temperature measurement of the signal or control connection in the circuit board 2 (connection pin 40 in the illustrated embodiment) and the temperature sensor 3 in order to bridge the spacing when the spacing D is not very small. These conductor traces only effect heat transfer, i.e., they have no electrical connection to other components 20. Figure 1 shows a situation where the temperature sensor 3 and the connection pin 40 have the smallest possible spacing; Figure 2 draws a situation where the spacing D is larger. In this case, heat transfer can be supported, for example, by the aforementioned conductor traces.

[0028] In one embodiment, as Figure 3 shown, the temperature measurement can be further improved in such a way that an element, preferably a plastic component 5 and / or a plastic mixture 5, is arranged on the upper side of the semiconductor package 4, which element has an opening pointing towards the upper side of the semiconductor package 4. Here, the element can be an element that is already provided on the semiconductor package 4, or it can be an element that is placed there specifically for temperature measurement. The chimney effect is generated through the opening, and this chimney effect conducts the heat dissipated by the semiconductor package 4 through the opening in the direction of the lower side of the circuit board 2 and thus to the temperature sensor 3. In this embodiment, the temperature sensor 3 is advantageously arranged on the lower side of the circuit board.

[0029] The proposed inverter assembly is part of a power electronics device, which is preferably used in an electric drive of a vehicle, which electric drive has a three-phase electric motor and a battery. The power electronics device has an inverter with a plurality of phases and is connected to the electric motor and the battery in order to convert the direct current from the battery into an alternating current that can be used for the electric motor by means of the inverter in order to drive the electric motor with this alternating current. In order to control the inverter, an ECU, i.e., an electronic controller, is provided, which is part of the power electronics device. The ECU is connected to the electric motor to control and regulate the electric motor and is connected to the inverter. The electric motor is in particular an electric axle drive.

[0030] Advantageously, a vehicle, such as a passenger vehicle or a commercial vehicle, has at least one such electric drive device. The vehicle is in particular a commercial vehicle, such as a lorry or a bus, or a passenger vehicle. The power electronics module (i.e., the power electronics) includes a DC / AC inverter (English: Inverter) having the structure described above. In addition, the power electronics module (i.e., the power electronics) may also include an AC / DC rectifier (English: Rectifier), a DC / DC converter (English: DC / DC Converter), a transformer (English: Transformer) and / or other electrical converters or parts of such converters, or parts thereof. In particular, the power electronics module is used to energize an electric machine, such as an electric motor and / or a generator.

[0031] List of reference numerals

[0032] 1 Control unit (ECU)

[0033] 2 Circuit board

[0034] 20 Structural element on circuit board 2

[0035] 3 Temperature sensor

[0036] 4 Semiconductor package

[0037] 40, 41 Connection pins of signal or control connection

[0038] 5 Component

[0039] D Spacing between temperature sensor 3 and connection pins 40 / 41 of signal or control connection

Claims

1. An inverter assembly, the inverter assembly comprising: - at least one semiconductor package (4), the semiconductor package having a current connection portion pointing to the outside of the semiconductor package (4) and at least one connection pin (40, 41) of a signal or control connection portion pointing to the outside of the semiconductor package (4); and - a circuit board (2) arranged at a certain distance above the semiconductor package (4), wherein: The at least one connecting pin (40, 41) is guided through a through hole of the circuit board (2) and is fastened to the circuit board (2); as well as - a temperature sensor (3) arranged on the circuit board (2) and close to the at least one connection pin (40, 41), so that the temperature sensor can measure the temperature of a power semiconductor arranged in the semiconductor package (4) and transmitted to the connection pin (40, 41).

2. The inverter assembly according to claim 1, wherein: The temperature sensor (3) is arranged on an upper side of the circuit board (2) facing away from the semiconductor package (4) or on a lower side facing the semiconductor package (4).

3. The inverter assembly according to claim 1 or 2, wherein: The temperature sensor (3) and the connecting pins (40, 41) are arranged at a certain minimum distance (D) so that the temperature sensor does not touch the connecting pins.

4. The inverter assembly according to claim 1 or 2, wherein: The temperature sensor (3) is arranged at a predetermined distance (D) from the connecting pins (40, 41), and at least one conductor track is provided on the circuit board (2), the conductor track leading from the temperature sensor (3) to the connecting pins (40, 41) and being used for heat transfer.

5. An inverter assembly according to any one of the preceding claims, wherein: The temperature sensor (3) is formed as a SMD component.

6. An inverter assembly according to any one of the preceding claims, wherein: The temperature sensor (3) is in operative connection with an evaluation unit (1) of the inverter, wherein the evaluation unit (1) is designed to process a temperature value measured by the temperature sensor (3) such that the evaluation unit can detect an exceeding of a predetermined temperature.

7. An inverter assembly according to any one of the preceding claims, wherein: A plastic component (5) or a plastic hybrid (5) having a central opening is arranged on the surface of the semiconductor package (4) facing the circuit board (2), and the temperature sensor (3) is arranged on the circuit board (2) in the region above the opening.

8. A power electronic device for operating a three-phase electric motor of a vehicle, wherein: The power electronic device has: - an inverter assembly according to any one of the preceding claims, and - At least one electronic controller connected to the electric motor for controlling and regulating the electric motor and to an inverter. 9 . An electric drive device for a vehicle, comprising a three-phase electric motor and a battery, and a power electronic device according to claim 8 connected to the electric motor and the battery.

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