Power electronics component and method for operating a power electronics component

Abstract

The invention relates to a power electronics component (100), in particular a semiconductor switch, comprising at least one semiconductor component (10), a printed circuit board (20) and a heat sink (40). The semiconductor component (10) is provided on a front face (26) of the printed circuit board (20), and the printed circuit board (20) is cooled from a rear face (28) of the printed circuit board (20) by means of the heat sink (40). The power electronics component also comprises a thermally conductive intermediate layer (30) which has a controllable thermal resistance (70) and is provided between the rear face (28) of the printed circuit board (20) and the heat sink (40), an open-loop and / or closed-loop control unit (50) for a closed-loop or open-loop control of the thermal resistance (70) of the thermally conductive intermediate layer (30), and a detection unit (60) which determines at least the temperature (62) and an electric current (66) of the at least one semiconductor component (10), said detection unit (60) being electrically coupled to the open-loop and / or closed-loop control unit (50). The invention also relates to a method for operating such a power electronics component (100).

Description

[0001] Power electronics component and method for operating a power electronics component

[0002] The invention relates to a power electronics component, in particular a semiconductor switch, and a method for operating a power electronics component, in particular a semiconductor switch.

[0003] In power electronics systems, semiconductor switches are used to efficiently control electrical energy. The semiconductor switch generates a large amount of heat, which must be dissipated to protect the component from overheating and damage.

[0004] In applications with changing operating conditions, thermal cycles occur that significantly impact the service life of the semiconductor switches and thus the power electronics system. Thermal cycles lead to thermal-mechanical stresses that can damage the connections in the power module assembly (e.g., bond wires). These stresses arise when the materials in the assembly expand differently due to different coefficients of expansion.

[0005] Constant temperatures can also reduce the lifetime of a semiconductor switch, but the impact is less pronounced than temperature fluctuations. Although the materials of the semiconductor device are also subjected to stress at constant temperatures, the stress is more uniform.

[0006] From DE 603 ​​05 867 T2 an optoelectronic module is known, comprising a module housing with a maximum specified operating temperature, an active optoelectronic component arranged in the module housing and a heating device arranged adjacent to the active optoelectronic component within the module housing for heating the active optoelectronic component to an operating temperature at or above the maximum specified operating temperature of the module housing, wherein the active optoelectronic component has operating characteristics at its operating temperature that are sufficient for its required function.The module further comprises a thermal switch for switchably providing either a relatively low or relatively high thermal impedance between the heating device serving as a heat source of the thermal switch and a heat sink of the thermal switch, the thermal switch comprising a channel having a first position between the heat source and heat sink sides of the thermal switch and a second position, a thermally conductive fluid within the channel, the fluid having a surface tension such that it remains substantially a single drop and does not flow spontaneously along the channel, and means for shifting the thermally conductive fluid between the first and second positions in the channel.

[0007] From DE 102012 208 745 A1 a device for cooling an electrical component in a vehicle is known, comprising a power supply module containing the electrical component for converting energy in the vehicle, wherein the power supply module has a first circuit board containing a first ceramic substrate for receiving the electrical component, a plurality of thermoelectric cells arranged on an underside of the first circuit board for conducting heat away from the electrical component, and a second circuit board containing a second ceramic substrate for receiving the plurality of thermoelectric cells on its upper side, wherein the first ceramic substrate and the second ceramic substrate serve to insulate the electrical component from the first circuit board and the second circuit board and to enable heat conduction from the electrical component via the plurality of thermoelectric cells.

[0008] An object of the invention is to provide an improved power electronics component, in particular semiconductor switches.

[0009] A further object is to provide a method for operating such an improved power electronics component, in particular a semiconductor switch.

[0010] The aforementioned objects are achieved by the features of the independent claims. Advantageous embodiments and advantages of the invention emerge from the further claims, the description, and the drawings.

[0011] According to one aspect of the invention, a power electronics component, in particular a semiconductor switch, is proposed, comprising at least one semiconductor component which is arranged on a front side of a printed circuit board of the power electronics component, wherein the printed circuit board is cooled from a rear side of the printed circuit board by means of a heat sink of the power electronics component, a thermally conductive intermediate layer with controllable thermal resistance which is arranged between the rear side of the printed circuit board and the heat sink, and a control and / or regulating unit for regulating or controlling the thermal resistance of the thermally conductive intermediate layer.

[0012] The lifetime of the power electronics component can be advantageously extended by reducing the number and amplitude of thermal cycles during operation. This can be achieved, for example, through appropriate cooling or by using switching techniques that reduce the number of thermal cycles.

[0013] To cool the components of the power electronics component, a heat sink is provided on the circuit board, which typically has a substantially constant cooling capacity. It is proposed to insert a thermally conductive intermediate layer between the heat sink and the circuit board, the thermal resistance or thermal conductivity of which can be controlled by applying an applied voltage. This allows the effective cooling capacity acting on the component to be adjusted in order to reduce the number and / or severity of thermal cycles occurring during operation of the component under varying loads, thus extending the service life of the power electronics component.

[0014] This is achieved by a thermally conductive intermediate layer with controllable thermal resistance, which can, for example, consist of a molecular layer. Such a thermal switch is known in principle and is described, for example, in Li M. et al., "Electrically gated molecular thermal switch," Science, AAAS (USA), Vol. 382 (2023), pages 585-589.

[0015] In the proposed power electronics component, such a layer acts as a thermal switch between the circuit board and the heat sink. The thermal resistance can be controlled or regulated via the control and / or regulation unit.

[0016] By using the thermal switch in conjunction with the control technique, a significant reduction in the temperature fluctuation amplitude of the semiconductor component can be achieved while maintaining the same output power of the semiconductor switch. This leads to an increase in the lifetime of the power electronics component. Unlike conventional techniques for reducing thermal cycling in semiconductor switches, the proposed approach does not generate additional power dissipation of the semiconductor switch, thus increasing system efficiency.

[0017] According to an advantageous embodiment of the power electronics component, the thermal resistance can be adjusted by applying an electrical voltage to the thermally conductive intermediate layer. By varying the electrical voltage, the thermal resistance of the intermediate layer arranged between a heat source and a heat sink can be advantageously adjusted to suit the application.

[0018] The power electronics component further comprises a sensing unit that determines at least one temperature and one electrical current of the at least one semiconductor component. The sensing unit is electrically coupled to the control and / or regulating unit. The temperature and current of the semiconductor component can thus be used in a suitable manner as reference variables for the control and / or regulating unit.

[0019] According to an advantageous embodiment of the power electronics component, the thermally conductive intermediate layer can be designed as a thermal switch. In particular, the thermal resistance can be varied by a factor of at least 1000%, preferably at least 1300%. In particular, the thermal resistance can be varied at a clock rate of at least 500 kHz, preferably at least 800 kHz, particularly preferably at least 1 MHz. Advantageously, the thermal resistance can thus be switched between a maximum value and a minimum value in a suitable manner and thus varied over a wide range of values. The switching of the thermal switch can occur at a sufficiently high speed. According to a further aspect of the invention, a method for operating a power electronics component, in particular a semiconductor switch, is proposed.The power electronics component comprises at least one semiconductor component arranged on a front side of a circuit board of the power electronics component, wherein the circuit board is cooled from a rear side of the circuit board by means of a heat sink of the power electronics component, a thermally conductive intermediate layer with controllable thermal resistance arranged between the rear side of the circuit board and the heat sink, and a control and / or regulating unit. The thermal resistance of the thermally conductive intermediate layer is regulated or controlled by means of the control and / or regulating unit. The power electronics component further comprises a detection unit electrically coupled to the control and / or regulating unit.

[0020] The proposed method can extend the lifetime of the power electronics component by reducing the number and amplitude of thermal cycles during operation. This can be achieved, for example, through appropriate cooling or by using switching techniques that reduce the number of thermal cycles.

[0021] In the power electronics component, a thermally conductive intermediate layer with a controllable thermal resistance acts as a thermal switch between the circuit board and the heat sink. The thermal resistance can advantageously be controlled or regulated via the control and / or regulation unit.

[0022] By using the thermal switch in conjunction with the proposed control method, a significant reduction in the temperature fluctuation amplitude of the semiconductor component can be achieved while maintaining the same output power of the semiconductor switch. This leads to an increase in the lifetime of the power electronics component. Unlike conventional techniques for reducing thermal cycling in semiconductor switches, the proposed approach does not generate additional power dissipation of the semiconductor switch, thus increasing system efficiency.

[0023] According to an advantageous embodiment of the method, the thermal resistance can be adjusted by applying an electrical voltage to the thermally conductive intermediate layer. By varying the electrical voltage, the thermal resistance of the intermediate layer arranged between a heat source and a heat sink can be advantageously adjusted to suit the desired value.

[0024] According to an advantageous embodiment of the method, the thermal resistance of the thermally conductive intermediate layer can be changed in a clocked manner. In particular, the thermal resistance can be changed by a factor of at least 1000%, preferably at least 1300%. In particular, the thermal resistance can be changed at a clock rate of at least 500 kHz, preferably at least 800 kHz, particularly preferably at least 1 MHz. Advantageously, the thermal resistance can thus be switched between a maximum value and a minimum value in a suitable manner and thus varied over a wide range of values. The switching of the thermal switch can occur at a sufficiently high speed.

[0025] The detection unit determines at least one temperature and one electrical current of the at least one semiconductor component, which are used as reference variables for the control and / or regulating unit. This allows the thermal resistance of the thermally conductive intermediate layer to be controlled or regulated in a suitable manner.

[0026] According to an advantageous embodiment of the method, the thermal resistance can be controlled such that the temperature of the at least one semiconductor component exhibits minimal temperature fluctuation. This advantageously allows a favorable increase in the service life of the power electronics component to be achieved.

[0027] According to an advantageous embodiment of the method, the thermal resistance can be controlled inversely to the current of the at least one semiconductor component. This advantageously reduces the magnitude of temperature fluctuations during operation of the power electronics component.

[0028] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also conveniently consider the features individually and combine them into useful further combinations. Herein:

[0029] Fig. 1 is a sectional view of a power electronics component, in particular a semiconductor switch, with a control and / or regulating unit and a detection unit for temperature and current according to an embodiment of the invention;

[0030] Fig. 2 is a symbolic representation of a thermal switch in the form of a thermally conductive intermediate layer with controllable thermal resistance;

[0031] Fig. 3 the controllable thermal resistance of the thermally conductive intermediate layer as a function of an applied electrical voltage; and

[0032] Fig. 4 is a representation of a temperature of the semiconductor component of the power electronics component, wherein the controllable thermal resistance of the thermally conductive intermediate layer is controlled according to the method according to the invention.

[0033] In the figures, identical or similar components are numbered with the same reference numerals. The figures show only examples and are not to be understood as limiting.

[0034] Figure 1 shows a sectional view of a power electronics component 100, in particular a semiconductor switch, with a control and / or regulating unit 50 and a detection unit 60 for temperature 62 and current 66 according to an embodiment of the invention.

[0035] The power electronics component 100 comprises a semiconductor component 10 arranged on a front side 26 of a printed circuit board 20. The printed circuit board 20 is cooled from a rear side 28 by means of a heat sink 40. The heat sink 40, with its cooling fingers, is in thermal contact with a cooling medium 42.

[0036] The semiconductor component 10 comprises the actual semiconductor 12, which is electrically connected to conductor tracks of the circuit board 20 via contact elements 14, for example, a lead frame. The circuit board 20 comprises metal layers 22, for example, copper layers, which form the conductor tracks and are electrically insulated from one another by ceramic layers 24. The ceramic layers 24 also form the mechanical structure of the circuit board 20.

[0037] The power electronics component 100 has a thermally conductive intermediate layer 30 with controllable thermal resistance 70, which is arranged between the back side 28 of the circuit board 20 and the heat sink 40.

[0038] The thermally conductive intermediate layer 30 with controllable thermal resistance 70 can, for example, consist of a molecular layer. Such a thermal switch 32 is known in principle and is described, for example, in Li M. et al., "Electrically gated molecular thermal switch," Science, AAAS (USA), Volume 382 (2023), pages 585-589.

[0039] Furthermore, a control and / or regulating unit 50 is provided for regulating or controlling the thermal resistance 70 of the thermally conductive intermediate layer 30. The control and / or regulating unit 50 is designed to apply an electrical voltage 52, relative to a voltage 54 of 0 V, to the thermally conductive intermediate layer 30. The thermal resistance 70 can be adjusted by applying the electrical voltage 52 to the thermally conductive intermediate layer 30.

[0040] By changing the thermal resistance 70 of the intermediate layer 30, a heat flow 78 between the semiconductor 12 and the heat sink 40 as well as the cooling medium 42 can be influenced.

[0041] Furthermore, a detection unit 60 is provided, which determines at least one temperature 62 and one electrical current 66 of the at least one semiconductor component 10. The detection unit 60 is electrically coupled to the control and / or regulating unit 50 and provides the temperature values ​​62 and the current values ​​66 as reference variables for the control and / or regulating unit 50.

[0042] The thermally conductive intermediate layer 30 is designed as a thermal switch 32.

[0043] Figure 2 shows a symbolic representation of the thermal switch 32 in the form of a thermally conductive intermediate layer 30 with controllable thermal resistance 70 according to Figure 1. The thermal switch 32 is arranged between a heat source 56 and a heat sink 58. The heat source 56 is formed in Figure 1 as the rear side 28 of the circuit board 20. The heat sink 58 represents the heat sink 40.

[0044] The thermal resistance 70 and thus the heat flow 78 between the heat source 56 and the heat sink 58 can be adjusted via the electrical voltage 52. The thermal resistance 70 can thus be changed, for example, by a factor of at least 1000%, preferably at least 1300%.

[0045] The switching behavior of the thermal switch 32 is demonstrated by the fact that the thermal resistance 70 can be changed in a clocked manner. Advantageously, the thermal resistance 70 can be changed at a clock rate of at least 500 kHz, preferably at least 800 kHz, particularly preferably at least 1 MHz.

[0046] In Figure 3, the controllable thermal resistance 70 of the thermally conductive intermediate layer 30 is shown as an example as a function of the applied electrical voltage 52.

[0047] The thermal resistance 70 is therefore determined via a linear relationship with the applied electrical voltage 52. The thermal resistance can be adjusted, for example, between a minimum resistance value 72 and a maximum resistance value 74 by changing the electrical voltage from a negative voltage 53 via the voltage zero point 54 to a positive voltage 55.

[0048] Figure 4 shows a representation of the temperature 62 of the semiconductor component 10 of the power electronics component 100. The controllable thermal resistance 70 of the thermally conductive intermediate layer 30 is controlled according to the method according to the invention.

[0049] Figure 4 shows the temporal behavior of the temperature 62, as well as the current 66 in the semiconductor component 10, the thermal resistance 70 and the electrical voltage 52 at the thermally conductive intermediate layer 30.

[0050] The thermal resistance 70 is controlled or regulated according to the method according to the invention such that a largely smooth temperature profile 62 results. A room temperature 63 and a maximum temperature 64 of the temperature 62 in the semiconductor component 10 are shown. Temperature 62 deviates little from the maximum temperature 64, with a slight temperature fluctuation 65. This means that the semiconductor component 10 is advantageously operated in a largely constant temperature range, which has a positive effect on the service life of the semiconductor component 10.

[0051] The temperature 62 increases slightly in the areas in which the current 66 assumes the maximum values ​​due to the switching behavior of the semiconductor component 10, represented by the difference 67 between the minimum and maximum current 66.

[0052] The thermal resistance 70, on the other hand, is controlled or regulated to minimum values ​​in the areas where the current 66 has its maximum values, represented by the difference 71 between the minimum and maximum thermal resistance 70.

[0053] The electrical voltage 52 applied to the thermally conductive intermediate layer 30 has the corresponding values ​​between negative voltage 53 and positive voltage 55 with zero crossing 54.

[0054] Advantageously, the thermal resistor 70 can be controlled or regulated such that the temperature 66 of the semiconductor component 10 exhibits a minimal temperature fluctuation 65. For this purpose, the temperature 66 can be maintained at a reference temperature by controlling or regulating the thermal resistor 70. The reference temperature can be application-specific.

[0055] The control method of the thermal resistance 70 depends on the heat flow 76 of the semiconductor component 10, which correlates with the current 66 through the semiconductor component 10. To limit the amplitude of the temperature fluctuation 65, the thermal resistance 70 can be controlled inversely proportional to the current 66 of the semiconductor component 10.

[0056] The thermal resistance 70 can be regulated to a minimum value at a maximum current 66, at which the maximum heat flow 76 occurs, and to a maximum value at a minimum current 66, at which a minimum heat flow 76 results. List of reference symbols

[0057] 10 Semiconductor component

[0058] 12 semiconductors

[0059] 14 Contacting element

[0060] 20 circuit board

[0061] 22 metal layers

[0062] 24 ceramic layer

[0063] 26 Front

[0064] 28 Back

[0065] 30 Intermediate layer

[0066] 32 thermal switch

[0067] 40 heat sinks

[0068] 42 Cooling medium

[0069] 50 Control and / or regulation unit

[0070] 52 Voltage at intermediate layer

[0071] 53 negative voltage

[0072] 54 Voltage 0 V

[0073] 55 positive voltage

[0074] 56 Heat source

[0075] 58 heat sink

[0076] 60 recording units

[0077] 62 Temperature Semiconductor

[0078] 63 room temperature

[0079] 64 maximum temperature

[0080] 65 Temperature fluctuation

[0081] 66 Electricity

[0082] 67 Current fluctuation

[0083] 70 thermal resistance

[0084] 71 Resistance fluctuation

[0085] 72 minimum thermal resistance

[0086] 74 maximum thermal resistance

[0087] 76 Heat flow

[0088] 80 time

[0089] 100 power electronics components

Claims

Patent claims 1. A power electronics component (100), in particular a semiconductor switch, comprising at least one semiconductor component (10), a printed circuit board (20), and a heat sink (40), wherein the semiconductor component (10) is arranged on a front side (26) of the printed circuit board (20), and wherein the printed circuit board (20) is cooled from a rear side (28) of the printed circuit board (20) by means of the heat sink (40), a thermally conductive intermediate layer (30) with controllable thermal resistance (70), which is arranged between the rear side (28) of the printed circuit board (20) and the heat sink (40), a control and / or regulating unit (50) for regulating or controlling the thermal resistance (70) of the thermally conductive intermediate layer (30), and a detection unit (60) which determines at least one temperature (62) and an electric current (66) of the at least one semiconductor component (10), wherein the detection unit (60) is connected to the control and / or regulating unit (50). is electrically coupled.

2. Power electronics component according to claim 1, wherein the thermal resistance (70) is adjustable by applying an electrical voltage (52) to the thermally conductive intermediate layer (30).

3. Power electronics component according to claim 1 or 2, wherein the thermally conductive intermediate layer (30) is designed as a thermal switch (32), in particular wherein the thermal resistance (70) is variable by a factor of at least 1000%, preferably at least 1300%, in particular wherein the thermal resistance (70) is variable with a clock rate of at least 500 kHz, preferably at least 800 kHz, particularly preferably at least 1 MHz.

4. A method for operating a power electronics component (100), in particular a semiconductor switch, according to one of the preceding claims, the power electronics component (100) comprising at least one semiconductor component (10), a printed circuit board (20) and a heat sink (40), wherein the semiconductor component (10) is arranged on a front side (26) of the printed circuit board (20), and wherein the printed circuit board (20) is cooled from a rear side (28) by means of the heat sink (40), a thermally conductive intermediate layer (30) with controllable thermal resistance (70), which is arranged between the rear side (28) of the printed circuit board (20) and the heat sink (40), a control and / or regulating unit (50), wherein the thermal resistance (70) of the thermally conductive intermediate layer (30) is regulated or controlled by means of the control and / or regulating unit (50), and a detection unit (60) which is connected to the control and / or regulating unit (50) is electrically coupled, wherein at least one temperature (62) and one electric current (66) of the at least one semiconductor component (10) are determined by means of the detection unit (60), which are used as reference variables for the control and / or regulating unit (50).

5. The method according to claim 4, wherein the thermal resistance (70) is adjusted by applying an electrical voltage (52) to the thermally conductive intermediate layer (30).

6. The method according to claim 4 or 5, wherein the thermal resistance (70) of the thermally conductive intermediate layer (30) is changed in a clocked manner, in particular wherein the thermal resistance (70) is changed by a factor of at least 1000%, preferably at least 1300%, in particular wherein the thermal resistance (70) is changed at a clock rate of at least 500 kHz, preferably at least 800 kHz, particularly preferably at least 1 MHz.

7. The method according to any one of claims 4 to 6, wherein the thermal resistance (70) is controlled such that the temperature (66) of the at least one semiconductor component (10) has a minimal temperature fluctuation (65).

8. Method according to one of claims 4 to 7, wherein the thermal resistance (70) is controlled inversely to the current (66) of the at least one semiconductor component (10).

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