Inverter with temperature measurement system

Abstract

The invention relates to an inverter having a temperature measuring system which is designed to measure the temperature of a semiconductor package of the inverter, the inverter having at least one phase and comprising a substrate, at least one half-bridge which is arranged on the substrate and has a high-side branch and a low-side branch, the high-side branches each have at least one semiconductor package acting as a high-side switch, and the low-side branches each have at least one semiconductor package arranged opposite and connected in parallel to the high-side switch and acting as a low-side switch, each semiconductor package being provided with an electrically non-conductive encapsulation layer. The temperature measuring system has at least one carrier material which is applied in a planar manner on or above the encapsulation layer of at least one of the semiconductor packages, and at least one temperature measuring element which is arranged on or in the material and is designed at least to detect a surface temperature of the encapsulation layer of the at least one semiconductor package.

Description

Technical Field

[0001] The invention relates to the field of electric vehicles, in particular to the field of monitoring power semiconductors which are semiconductor packages and which are installed in inverters of power electronics modules for operating electric drives. Background Art

[0002] In recent decades, the use of electronic device modules, such as power electronic device modules, in motor vehicles has increased dramatically. This is due to the need to improve fuel saving and vehicle performance on the one hand, and on the other hand due to the progress of semiconductor technology. The main components of such electronic device modules, also known as power electronics, are electronic control units, also known as ECUs (electronic control units), which are connected to or part of one or more vehicle controllers and receive control signals and / or information based on, for example, driving behavior or signals of other controllers, as well as direct current / alternating current inverters (Inverters), which are used to provide multi-phase alternating current (AC) to electric machines, such as electric motors or generators. In this case, the direct current generated by a direct current energy source, such as a battery or a storage battery, is converted into a multi-phase alternating current. For this purpose, the inverter includes a large number of electronic components, such as semiconductor power switches, also known as power semiconductors, which are used to implement bridge circuits (such as half bridges).

[0003] Power semiconductors are temperature sensitive and are therefore cooled by a cooling system. 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 in order to avoid damage to the entire inverter system. In order to monitor the temperature of the power semiconductors, a variety of options are known. Here, the temperature monitoring element can be directly integrated into the power semiconductor module, for example as a temperature sensor or a sensor diode. The temperature can also be measured directly on the semiconductor package, that is, on the housing (encapsulation layer) of the power semiconductor. Here, the measurement can be carried out in contact with the housing and in contact with the housing.

[0004] Depending on the location of the temperature sensor, the challenges of temperature measurement in the inverter are also the isolation between high voltage and low voltage potentials. Attention must also be paid to the signal contact, that is, the distance between the measurement and the further processing of the measured value, as well as the response time of the temperature sensor and the available installation space, especially on the circuit board for signal processing. Thermal contact must also be taken into account in the planning of the temperature measurement in the event of vibrations and thermal expansion, etc. Summary of the invention

[0005] Since there is always a need for improvement in the temperature measurement of power semiconductors of inverters, it is an object of the present invention to provide an improved temperature measurement system for measuring the temperature of power semiconductors of inverters.

[0006] This object is achieved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims. Further features and advantages of the invention are obtained from the subsequent description of the embodiments of the invention with the aid of the drawings showing details according to the invention and from the claims. The individual features can be realized individually or in any combination in the variants of the invention.

[0007] An inverter is provided, which has a temperature measurement system, which is configured to measure the temperature of a semiconductor package of the inverter, wherein the inverter has at least one phase and includes: a substrate, at least one half-bridge arranged on the substrate and having a high-side branch and a low-side branch, wherein the high-side branch has at least one semiconductor package used as a high-side switch, and the low-side branch has at least one semiconductor package arranged opposite to the high-side switch and connected in parallel therewith and used as a low-side switch. Each semiconductor package is provided with a non-conductive encapsulation layer. The temperature measurement system has at least one carrier material applied in a flat manner on or above the encapsulation layer of at least one semiconductor package, and at least one temperature measuring element arranged on or in the material, which is configured at least to detect the surface temperature of the encapsulation layer of at least one semiconductor package.

[0008] In one embodiment, the temperature measuring element is designed as a temperature sensor or a resistance strip.

[0009] In one embodiment, a temperature measuring element is arranged for each semiconductor package, or a temperature measuring element is arranged for each phase, or a temperature measuring element is arranged for each high-side branch and / or each low-side branch, or one temperature measuring element is arranged for all phases.

[0010] In one embodiment, the carrier material extends in a U-shaped manner over one phase or in a U-shaped manner over all phases. In one embodiment, the carrier material is constructed as two strips, each of which extends continuously over one phase or all phases on the high side branch or the low side branch. In one embodiment, the carrier material extends in a square manner over the semiconductor package.

[0011] In one embodiment, the carrier material is fastened to one or more semiconductor packages. In one embodiment, the carrier material is integrated in an encapsulation layer of a busbar arranged directly above the semiconductor package.

[0012] In one embodiment, the carrier material is embodied as a film or a flexible film or a PCB or a copper tape.

[0013] In one embodiment, each carrier material has at least one contact region on at least one region thereof in order to produce an operative connection between the temperature measuring system and an external processing device.

[0014] Furthermore, an electronics module having the described inverter is provided.

[0015] Furthermore, an electric motor for a vehicle, in particular an electric axle drive, is provided, which has at least one electric drive and the described electronics module for controlling the electric motor.

[0016] Furthermore, a vehicle is provided having the described electric motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Preferred embodiments of the invention are explained in detail below with reference to the drawings.

[0018] Figures 1 to 3 Inverters with a temperature measurement system according to different embodiments of the present invention are respectively shown.

[0019] Figures 4 to 6 Inverters with a temperature measurement system according to different alternative embodiments of the present invention are respectively shown.

[0020] Figure 7 An inverter with a temperature measurement system according to a further alternative embodiment of the present invention is shown.

[0021] In the following description of the figures, identical elements or functions are provided with the same reference symbols. DETAILED DESCRIPTION

[0022] Inverters currently known for use in the field of electric vehicles are usually formed in three phases. Here, a so-called three-phase module can be used, in which a single common substrate 2 is provided for all three phases P1 to P3, on which a semiconductor package 4 encapsulated with a potting material is arranged, as shown in the figure. The contact area extends to the outside of the encapsulation layer of the semiconductor package 4 in order to contact the corresponding busbar. The semiconductor package 4 is directly fastened to the substrate 2, for example, sintered thereon.

[0023] The substrate 2 serves as a carrier plate and is formed of a sufficiently stable material with good thermal conductivity, such as copper, so as to provide sufficient heat dissipation and fixation of the semiconductor package 4. Therefore, the substrate is not configured as a circuit board and does not have lines for conducting current or signals. The substrate can be formed of a conductive material and thus also provides a ground potential GND. However, the substrate can also be composed of a non-conductive material, wherein the ground potential GND can also be provided by screws.

[0024] The semiconductor packages 4 are usually arranged opposite each other so that two of the semiconductor packages form a half bridge with a central AC current tap 7, wherein one semiconductor package 4 is used as a high-side switch and the other semiconductor package is used as a low-side switch. Power semiconductors such as MOSFETs, IGBTs, etc. connected in parallel to each other are present in each semiconductor package 4.

[0025] Each phase P1 - P3 may be provided with one or more half bridges. The figures show by way of example that each phase P1 - P3 has three half bridges.

[0026] The direct current busbars and the alternating current busbars are arranged above the semiconductor package 4 and are in electrical contact with the associated current connections of the half bridge.

[0027] In addition, if Figure 7 As shown, a DC busbar, preferably a negative DC busbar 6, extends over the entire surface of the semiconductor package 4. The other busbars (positive DC busbar and AC busbar) are not shown, but are arranged in a stacked manner below or above the negative DC busbar 6 and are electrically connected to the associated current connections of the semiconductor package 4, wherein an AC current tap 7 is arranged centrally between two mutually opposite semiconductor packages 4, as shown in the figure.

[0028] In known embodiments, the negative DC current busbar 6 has openings, so that the high-voltage current pins and / or signal pins and / or current pins of the semiconductor package 4, for example, the positive DC current busbar, can be guided above the negative DC current busbar 6 (upper side), and thus the AC current connection of the AC current busbar located above the negative DC current busbar 6 can be led to the lower side of the negative DC current busbar 6 toward the AC current tap 7 of the semiconductor package 4. Here, one or more openings are usually also provided in the negative DC current busbar 6, so as to guide one or more temperature sensors to the lower side of the negative DC current busbar 6 to measure the temperature of the semiconductor package 4.

[0029] As already mentioned above, the challenges in temperature measurement in inverters are, in particular, the isolation between high and low voltage potentials, depending on the location of the temperature sensor. Attention must also be paid to the signal contact, i.e. the distance between the measurement of the measured value and the further processing of the measured value, as well as the response time of the temperature sensor and the available installation space, in particular the space on the circuit board arranged above the busbar for signal processing. Thermal contacts must also be taken into account in the planning of the temperature measurement in the event of vibrations and thermal expansion, etc.

[0030] Therefore, according to the present invention, a temperature measurement system for an inverter is proposed, which provides monitoring of the surface temperature of the plastic encapsulation layer of the power semiconductor. That is, the temperature is measured directly on the encapsulation layer 60 of the semiconductor package 4. Then, the measurement result (processed or unprocessed data) is transmitted to the processing device via the contact area 9.3. In the case of identifying that at least one semiconductor package 4 is overheated, corresponding measures as known in the prior art are taken.

[0031] Different embodiments of the temperature measuring system are described below with reference to the accompanying drawings. Common to all embodiments is that the temperature measuring element is arranged on a layered carrier material 8. The carrier material 8 can be a film applied flat to the semiconductor package 4, or it can also be a flexible circuit board or a copper tape.

[0032] In a first embodiment, the temperature measuring element of the temperature measuring system is designed as a temperature sensor 9.1, which is fastened to the carrier material 8, for example, by means of adhesive bonding. Thermal conductors (NTC), Pt100 / Pt1000 elements and optical sensors can be used as temperature sensors 9.1, wherein in the latter case, the processing of the measured data is realized in an external processing device, which is operatively connected to one or more temperature sensors 9.1 via one or more contact areas 9.3. The carrier material 8 is fastened to the upper side of the semiconductor package 4, i.e., the housing, for example, by means of adhesive bonding.

[0033] Figure 1 A design of the first embodiment is shown, in which a separate temperature measurement system is provided for each phase P1 to P3. Here, the carrier material 8 is arranged in a U-shape, i.e., one side is in a row ( Figure 1 and the other side extends in a parallel row ( Figure 1 The third side passes over the AC current tap 7 ( Figure 1 In this embodiment, at the two open ends ( Figure 1In addition, in this embodiment, a separate temperature sensor 9.1 is provided for each semiconductor package 4, which is arranged essentially centrally on the housing. If the position in the semiconductor package 4 that is most sensitive to temperature rise is known, the temperature sensor 9.1 can be arranged above this area, wherein the carrier material 8 can also be adapted accordingly in its shape and size.

[0034] Figure 2 FIG. 4 shows another embodiment of the first embodiment, in which a single temperature measuring system is provided for all phases P1 to P3. Figure 1 The difference in the design in this case is that the carrier material 8 extends over all semiconductor packages 4 of all phases P1 to P3, so that the two sides of the "U" are lengthened. In addition, contact areas 9.3 are also provided at the two open ends, and a separate temperature sensor 9.1 is provided for each semiconductor package 4, as in Figure 1 As shown in the design.

[0035] Figure 3 Another design of the first embodiment is shown, in which two temperature measuring systems are provided. Here, the carrier material 8 is constructed as two separate strips extending continuously in parallel on all phases P1 to P3, one of which extends on the semiconductor package 4 used as the high side and the other extends on the semiconductor package 4 used as the low side. In addition, as in Figure 1 As in the embodiment shown, a contact region 9 . 3 is also provided at each of the two open ends, and a separate temperature sensor 9 . 1 is provided for each semiconductor package 4 .

[0036] In a second embodiment, the temperature measuring element of the temperature measuring system is designed as a resistance strip 9.2, such as Figures 4 to 6 As shown. These resistor strips are fastened to the carrier material 8, for example by means of adhesive bonding, or are embedded in the carrier material 8, for example as conductor tracks of a PCB (printed circuit board). The temperature measurement is thus realized by a four-wire measurement and no temperature sensor is required. The material of the resistor strips 9.2 is a thermally conductive material, advantageously copper, whose known temperature dependence is used for the measurement. Of course, in this case, the carrier material 8 cannot be made of copper.

[0037] Figure 4 A fragment with only one phase P1 is shown, which schematically illustrates two different designs of the second embodiment. Figure 4On the upper semiconductor packages 4, each semiconductor package 4 is provided with a resistor track 9.2 with its own contact area 9.3. In this case, the temperature of each semiconductor package 4 can be measured, wherein a mixed temperature is always present. It can be provided that the resistor track 9.2 extending on the semiconductor package 4 that is not to be measured is thermally insulated on its underside. The insulation can also be part of the carrier material 8. Figure 4 On the lower semiconductor package 4 in FIG. 4 , a resistor track 9 . 2 is shown which is continuous on all semiconductor packages 4 and has only a single contact area 9 . 3 . In this case, the temperature of all semiconductor packages 4 on which the resistor track 9 . 2 is arranged is detected as a mixed temperature.

[0038] Figure 5 A design of the second embodiment is shown, in which a single resistor track 9.2 extends over all semiconductor packages 4 of phase P1. Figure 1 1 and 2. The semiconductor package 4 is arranged in a U-shape as in FIG. 1, ie one side extends over a row of semiconductor packages 4 and the other side extends over a parallel row of semiconductor packages 4. A third side connects the two sides across the AC current tap 7.

[0039] Figure 6 Another embodiment of the second embodiment is shown, in which a single resistor track 9.2 extends over all semiconductor packages 4 of all phases P1 to P3. Figure 2 The two sides of the "U" are arranged in a U-shape as in FIG.

[0040] exist Figure 5 and Figure 6 In the embodiment shown, Figure 4 Analogously to the above, as an alternative to a single resistor track 9 . 2 , a plurality of resistor tracks 9 . 2 may also be provided in order to monitor the temperature of each semiconductor package 4 .

[0041] Because the negative DC current busbar 6 is placed completely above the semiconductor package 4, it may have undesirable electrical interactions with components placed above or below it, especially the positive DC current busbar and the AC current busbar. Therefore, a complete encapsulation layer 60 of the negative DC current busbar 6 is provided on the area where the negative DC current busbar covers other busbars, that is, the negative DC current busbar is not electrically contacted, so as to provide electrical insulation relative to its environment, especially the positive DC current busbar and the AC current busbar. Therefore, the encapsulation layer 60 is especially present above the semiconductor package 4, but not at the electrical contact area. As already known from the prior art and therefore not described in detail, the encapsulation layer 60 is made of an electrically insulating material, preferably constructed as a molding material, and is therefore suitable for injection molding or molding (flow process).

[0042] As already described with respect to the negative DC current busbar 6 placed all over the semiconductor package 4, the encapsulation layer 60 also has various openings for passing various components from its lower side pointing to the substrate 2 to its opposite upper side (or vice versa). Of course, these openings correspond to the openings in the negative DC current busbar 6 and therefore overlap each other.

[0043] In one embodiment, it is provided that the temperature measuring system is integrated into the encapsulation layer 60 of the negative direct current busbar, in particular embedded therein, such as in Figure 7 This can be achieved by integrating the temperature measuring system into the encapsulation layer 60 during the encapsulation process. The embodiment of the temperature measuring system can be any of the described embodiments, i.e. not only individual temperature sensors 9.1 applied to the carrier material 8 (see Figures 1 to 3 ), and the resistor section 9.2 applied to the carrier material 8 (see Figures 4 to 6 The contact area 9.3 is also retained. The temperature of the encapsulation layer 60 of the semiconductor package 4 can also be monitored when the temperature measuring elements 9.1, 9.2 are not in direct contact with the encapsulation layer 60 of the semiconductor package 4, but are at a small distance therefrom, as in the case of the negative DC busbar 6.

[0044] The surface temperature of the semiconductor package 4 can be monitored by means of the proposed temperature measuring system, wherein a flexible arrangement of the temperature measuring elements 9 . 1 , 9 . 2 can be realized in a simple manner.

[0045] The proposed temperature measurement system can also be used in multi-phase modules with more than three phases or in single-phase modules, wherein each individual phase of the inverter (and thus each module) is provided with a temperature measurement system, as for example in Figure 1 and Figure 5 As in the embodiment shown.

[0046] In all embodiments, the carrier material 8 can also be arranged over the entire surface of all semiconductor packages 4 , provided that it has corresponding openings and recesses for leading through, for example, alternating current contacts.

[0047] The invention has been described with reference to a negative DC current busbar 6 arranged all the way above the semiconductor package 4. This is a preferred embodiment, but it is also possible to integrate the temperature measurement system into one of the other busbars (DC / AC), provided that it is located sufficiently close above the semiconductor package 4.

[0048] A great advantage of the proposed temperature measuring system is that, in view of the number of temperature measuring elements, a very modular structure is possible. For example, one or more temperature measuring elements can be provided for each phase P1 to P3, or a temperature measuring element can be provided for each semiconductor package 4, or a temperature measuring element can be provided for each high-side branch or each low-side branch of the semiconductor package 4.

[0049] The proposed inverter 1 (DC / AC converter) is part of an electronics module and preferably has three phases P1 to P3. The electronics module is used to operate a three-phase electric motor of a vehicle and is connected to an electronic control unit (ECU for short) serving as a drive in terms of signal technology. The ECU is used to control and regulate the inverter and the electric motor.

[0050] The electronics module is operatively connected to the electric motor and the battery of the vehicle in order to generate an alternating current for the electric motor from the direct current provided by the battery by means of an inverter, thereby driving the electric motor. The electric motor is in particular an electric axle drive. Advantageously, the vehicle, for example a passenger car or a commercial vehicle, has at least one such drive.

[0051] Reference numerals

[0052] P1~P3 Phase 1, Phase 2, Phase 3

[0053] 1 Three-phase module

[0054] 2 substrate

[0055] 4 Semiconductor packaging

[0056] 6 Negative DC current bus

[0057] 60 Encapsulation layer of negative DC current busbar

[0058] 7 AC current tap

[0059] 8 Loading material

[0060] 9.1 Temperature Sensor

[0061] 9.2 Resistor Segment

[0062] 9.3 Contact area

Claims

1. An inverter (1) having a temperature measurement system, the temperature measurement system being configured to measure the temperature of a semiconductor package (4) of the inverter (1), wherein: The inverter (1) has at least one phase (P1-P3) and comprises: - base plate (2), - at least one half-bridge arranged on the substrate (2) and having a high-side branch and a low-side branch, the high-side branch each having at least one semiconductor package (4) used as a high-side switch, the low-side branch each having at least one semiconductor package (4) used as a low-side switch and arranged opposite to the high-side switch and connected in parallel therewith, wherein each semiconductor package (4) is provided with a non-conductive encapsulation layer, Wherein, the temperature measurement system comprises: - at least one carrier material (8) applied in a flat manner on or above the encapsulation layer of at least one of the semiconductor packages (4), and at least one temperature measuring element arranged on or in the material, the temperature measuring element being designed at least to detect the surface temperature of the encapsulation layer of at least one semiconductor package (4).

2. The inverter (1) according to claim 1, wherein: The temperature measuring element is designed as a temperature sensor (9.1) or as a resistance strip (9.2).

3. The inverter (1) according to claim 1 or 2, wherein: A temperature measuring element is arranged for each semiconductor package (4), or a temperature measuring element is arranged for each phase (P1-P3), or a temperature measuring element is arranged for each high-side branch and / or each low-side branch, or a temperature measuring element is arranged for all phases (P1-P3).

4. The inverter (1) according to any one of the preceding claims, wherein: The carrier material (8) - extends in a U-shaped manner over one phase (P1 to P3) or extends in a U-shaped manner over all phases (P1 to P3), or - is constructed as two belts, each of which extends continuously on one phase or all phases (P1 to P3) on the high-side branch or the low-side branch, or - extends in a direction above the semiconductor package (4).

5. The inverter (1) according to any one of the preceding claims, wherein: The carrier material (8) - fastened to one or more semiconductor packages (4), or - integrated into an encapsulation layer of a busbar arranged directly above the semiconductor package (4).

6. The inverter (1) according to any one of the preceding claims, wherein: The carrier material (8) is embodied as a film or a flexible film or a PCB or a copper tape.

7. The inverter (1) according to any one of the preceding claims, wherein: Each carrier material (8) has at least one contact region (9.3) on at least one region thereof in order to produce an operative connection between the temperature measuring system and an external processing device. 8 . Electronics module comprising an inverter ( 1 ) according to claim 1 . 9 . An electric motor for a vehicle, in particular an electric axle drive, comprising at least one electric drive and an electronics module according to claim 8 for controlling the electric motor.

10. A vehicle having an electric motor according to claim 9.

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