Inverter arrangement for temperature monitoring of power semiconductors

Abstract

An inverter arrangement is proposed, comprising at least one semiconductor package with power connections pointing outside the semiconductor package, as well as at least one connection pin of a signal or control connection pointing outside the semiconductor package, as well as a printed circuit board arranged at a distance above the semiconductor package or packages, wherein the at least one connection pin is guided through a through-hole of the printed circuit board and fastened to the printed circuit board, and a temperature sensor arranged on the printed circuit board and in such a close proximity to the at least one connection pin that it can measure the temperature of a power semiconductor arranged in the semiconductor package that is transmitted to the connection pin.

Description

[0001] The present invention relates to the field of electromobility, in particular to monitoring the temperature of power semiconductors of a semiconductor package that are installed in an inverter of a power electronics module for operating an electric drive.

[0002] The use of electronic modules, such as power electronics modules, in motor vehicles has increased significantly in recent decades. This is due on the one hand to the need to improve fuel economy and vehicle performance, and on the other hand to advances in semiconductor technology. The main components of such an electronic module, also known as power electronics, are an electronic control unit (ECU), which is connected to or forms part of the vehicle's control unit(s) and receives control signals and / or information based, for example, on driving behavior or signals from other control units, and a DC / AC inverter, which is used to supply electrical machines such as electric motors or generators with multi-phase alternating current (AC).In this process, a direct current generated by a DC energy source, such as a battery or accumulator, is converted into a multi-phase alternating current. For this purpose, the inverters comprise a variety of electronic components that create bridge circuits (such as half-bridges), such as semiconductor power switches, also known as power semiconductors.

[0003] The power semiconductors are temperature-sensitive and are therefore cooled by a cooling system. Nevertheless, it is 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 prevent damage to the entire inverter system. Several options are known for monitoring the temperature of the power semiconductors. Temperature monitoring can be integrated directly into the power semiconductor package, e.g., as a temperature sensor or as sensing diodes. The temperature can also be measured directly on the semiconductor packages, i.e., on the housing (the casing) of the power semiconductors. The measurement can be performed either with contact with the housing or without contact.

[0004] Since many of these solutions are not only expensive but also complex, the object of the invention is to provide improved temperature measurement of power semiconductors in a semiconductor package.

[0005] This object is achieved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0006] An inverter arrangement is proposed, comprising at least one semiconductor package with power connections pointing outside the semiconductor package, as well as at least one connection pin of a signal or control connection pointing outside the semiconductor package, as well as a printed circuit board arranged at a distance above the semiconductor package or packages, wherein the at least one connection pin is guided through a through-hole of the printed circuit board and fastened to the printed circuit board, and a temperature sensor arranged on the printed circuit board and in such a close proximity to the at least one connection pin that it can measure the temperature of a power semiconductor arranged in the semiconductor package that is transmitted to the connection pin.

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

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

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

[0010] In one version, the temperature sensor is designed as an SMD component.

[0011] In one embodiment, the temperature sensor is operatively connected to an evaluation unit of the inverter, wherein the evaluation unit is configured to process the temperature values ​​measured by the temperature sensor in such a way that it can detect when a predetermined temperature is exceeded.

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

[0013] Furthermore, power electronics for operating a three-phase electric motor of a vehicle are provided, wherein the power electronics comprises the inverter arrangement and at least one electronic control unit which is connected to the electric motor for its control and regulation and to the inverter.

[0014] Furthermore, an electric drive of a vehicle is provided, comprising a three-phase electric motor and a battery, as well as the power electronics connected to both.

[0015] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, with reference to the figures of the drawing, which illustrate details of the invention, and from the claims. The individual features can be implemented individually or in combination in a variant of the invention.

[0016] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Fig. 1 shows an inverter structure with a temperature sensor arranged according to an embodiment of the present invention. Fig. Figure 2 shows an inverter structure with a temperature sensor arranged according to an alternative embodiment of the present invention. Fig. Figure 3 shows an inverter structure with a temperature sensor arranged according to an alternative embodiment of the present invention.

[0017] In the following descriptions of the figures, the same elements or functions are provided with the same reference symbols.

[0018] A semiconductor package 4 refers to one or more encapsulated (housed in a package) power semiconductors (chips) that serve as high-side or low-side switches, including (unencapsulated) terminal pins for electrical or signal contact. The term "semiconductor package 4" also refers to a half-bridge module in which high-side and low-side switches are already integrated together in a single package.

[0019] Current semiconductor packages 4, in addition to their power connections (DC and AC), have at least one signal or control connection leading outside the semiconductor package 4, which can be, for example, a gate connection or a Kelvin source connection. These signal or control connections are arranged / attached inside the semiconductor package 4 near the power semiconductor (chip). Their connection pins 40, 41, which lead from there to the outside, are contacted during assembly on a printed circuit board 2 arranged above the semiconductor packages 4, usually by means of THT, i.e. by leading the connection pins from the underside of the printed circuit board through a through-hole to a top side and then being attached there, e.g. by soldering.

[0020] As already mentioned at the beginning, it is important to monitor the temperature of a semiconductor package 4 in order to be able to take measures in the event of overheating to protect the semiconductor package 4, or more precisely the power semiconductor(s) contained therein. Temperature sensors are used for temperature monitoring. These sensors are arranged, for example, near the semiconductor package 4 and measure the temperature there. Since some very complex methods for temperature measurement exist, a simple concept is proposed below that is both cost-effective and easy to manufacture, especially with a cost-effective temperature sensor.

[0021] It is proposed to use one of the connection pins 40 or 41 of a signal or control connection, which are already present in the currently used semiconductor packages 4, 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 connections are arranged in the vicinity of the power semiconductor (chip) and are made of a thermally conductive material such as copper, they absorb its heat and transport it via their respective connection pin 40 or 41 to the printed circuit board 2. In this respect, one of the connection pins 40 or 41 can be used for the proposed temperature measurement. Furthermore, according to the invention, a temperature sensor 3 is arranged on the printed circuit board 2 as close as possible to, but not in physical contact with, the power semiconductor (chip), i.e. at a distance D (only in Fig. 2) to the connection pin 40 or 41.

[0022] The temperature sensor 3 can be mounted on a top side of the circuit board 2, as shown in Fig. 1, or a bottom side facing the semiconductor package 4, as in Fig. 2. It is preferably formed as an SMD (surface mounted device), since it can then be attached to the circuit board 2 together with other components 20 in one of the SMT processes that are to be carried out anyway for assembling the circuit board 2.

[0023] The temperature sensor 3 is also operatively connected to an evaluation unit 1, e.g. via conductor tracks integrated in the circuit board 2. This evaluation unit 1 can be part of an (external) electronic control unit of the vehicle's power electronics or a separate, operatively connected unit (external or arranged on the circuit board 2). It processes the data transmitted by the temperature sensor 3 to determine whether the detected temperature lies within a permitted range. If this is not the case, i.e. if a predetermined temperature is detected, the evaluation unit 1 initiates appropriate measures to protect the power semiconductor (chip), e.g. switching off the inverter. For this purpose, it is operatively connected to the electronic control unit of the power electronics.

[0024] Furthermore, one or more conductor tracks can be provided in the circuit board 2 between the connection pin used for temperature measurement (connection pin 40 in the illustrated embodiment) of the signal or control connections and the temperature sensor 3 in order to bridge the distance D, if this is not very small. These conductor tracks only carry out heat transfer and therefore have no electrical connections to other components 20. Fig. 1 shows the temperature sensor 3 with the minimum possible distance to the connection pin 40, in Fig. 2, a larger distance D is shown. In this case, heat transfer can be supported, for example, by the described conductor tracks.

[0025] In one embodiment, the temperature measurement can be further improved by arranging an element, preferably a plastic component 5 and / or a plastic hybrid part 5, on the top side of the semiconductor package 4, which element has an opening facing the top side of the semiconductor package 4, as shown in Fig. 3. The element can be an element already provided on the semiconductor package 4 or an element placed there specifically for temperature measurement. The opening creates a chimney effect, which conducts the heat emitted by the semiconductor package 4 through the opening toward the underside of the circuit board 2 and thus to the temperature sensor 3. In this embodiment, the temperature sensor 3 is advantageously arranged on the underside of the circuit board.

[0026] The proposed inverter arrangement is part of a power electronics system, which is preferably used in an electric drive of a vehicle having a three-phase electric motor and a storage battery. The power electronics system has a multi-phase inverter and is connected to the electric motor and storage battery in order to convert the direct current received from the storage battery into alternating current usable by the electric motor by means of the inverter, thereby driving the electric motor. An ECU, i.e., an electronic control unit, is provided as part of the power electronics system to control the inverter. The ECU is connected to the electric motor for its control and regulation, and to the inverter. The electric motor is, in particular, an electric axle drive.

[0027] A vehicle, e.g. a passenger car or a commercial vehicle, advantageously has at least one such electric drive. The vehicle is in particular a commercial vehicle such as a truck or a bus, or a passenger car. The power electronics module (i.e. the power electronics) comprises a DC / AC inverter with the described structure. It can also comprise or be a part of an AC / DC rectifier, a DC / DC converter, a transformer and / or another electrical converter or a part of such a converter. In particular, the power electronics module serves to supply current to an electric machine, e.g. an electric motor and / or a generator. List of reference symbols 1 control unit (ECU) 2 circuit board 20 components on 2 3 Temperature sensor 4 Semiconductor package 40, 41 Connection pins of the signal or control connections 5 component D Distance between 3 and 40 / 41

Claims

[1] Inverter arrangement, comprising: - at least one semiconductor package (4) with power connections pointing outside the semiconductor package (4), as well as at least one connection pin (40, 41) of a signal or control connection pointing outside the semiconductor package (4), and - a printed circuit board (2) arranged at a distance above the semiconductor package(s) (4), wherein the at least one connection pin (40, 41) is guided through a through hole of the printed circuit board (2) and is fastened to the printed circuit board (2), and - a temperature sensor (3) arranged on the circuit board (2) and close to the at least one connection pin (40, 41) in such a way that it can measure the temperature of a power semiconductor arranged in the semiconductor package (4) transmitted to the connection pin (40, 41). [2] Inverter arrangement according to claim 1, wherein the temperature sensor (3) is arranged on an upper side facing away from the semiconductor package (4) or on an underside of the printed circuit board (2) facing the semiconductor package (4). [3] Inverter arrangement according to claim 1 or 2, wherein the temperature sensor (3) is arranged at a minimum distance (D) from the connection pin (40, 41) such that it does not touch it. [4] Inverter arrangement according to claim 1 or 2, wherein the temperature sensor (3) is arranged at a predetermined distance (D) from the connection pin (40, 41), and wherein at least one conductor track is provided on the circuit board (2), which is led from the temperature sensor (3) to the connection pin (40, 41) and which serves for heat transfer. [5] Inverter arrangement according to one of the preceding claims, wherein the temperature sensor (3) is formed as an SMD component. [6] Inverter arrangement according to one of the preceding claims, wherein the temperature sensor (3) is operatively connected to an evaluation unit (1) of the inverter, wherein the evaluation unit (1) is designed to process the temperature values ​​measured by the temperature sensor (3) in such a way that it can detect when a predetermined temperature is exceeded. [7] Inverter arrangement according to one of the preceding claims, wherein a plastic component (5) or a plastic hybrid part (5) with a central opening is provided on a surface of the semiconductor package (4) facing the printed circuit board (2), and wherein the temperature sensor (3) is arranged on the printed circuit board (2) in a region above the opening. [8] Power electronics for operating a three-phase electric motor of a vehicle, the power electronics comprising: - an inverter arrangement according to one of the preceding claims, and - at least one electronic control unit connected to the electric motor for its control and regulation and to the inverter. [9] Electric drive of a vehicle, comprising a three-phase electric motor and an accumulator, as well as power electronics connected to both according to claim 8.

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