Method for the targeted adjustment of the cooling capacity of a cooling system for cooling a pulse inverter

Abstract

Method for targeted adjustment of a cooling power of a cooling system (2) for cooling a pulse inverter (6) with a plurality of semiconductor chips (4), comprising the steps: - Operation (100) of the pulse inverter (6) in a test bench operation, - Determining (200) a current operating temperature of the majority of semiconductor chips (4) in the test bench operation using a sensor unit (20), - Determining (300) a required cooling capacity for cooling the semiconductor chips (4) based on the determined current operating temperature using a processing unit (22), - Adjusting (400) the cooling power of the cooling system (2) based on the determined required cooling power of the majority of semiconductor chips (4) by means of a control unit (24), wherein determining (200) a current operating temperature near the semiconductor chips (4) is carried out, wherein determining (300) the required cooling power for cooling the semiconductor chips (4) based on the determined current operating temperature near the semiconductor chips (4) is carried out by an additional calculation.

Description

[0001] The present invention relates to a method and a system for the targeted adjustment of a cooling capacity of a cooling system for cooling a pulse inverter, and to a pulse inverter with a targeted adjustment of the cooling system.

[0002] Pulse inverters are used to convert direct current (DC) into alternating current (AC). They are employed, for example, in electric vehicles to convert the DC from a battery into AC that powers an electric motor. Pulse inverters utilize semiconductor chips for this DC-AC conversion.

[0003] A disadvantage is that occasional deviations in switching times occur between individual semiconductor chips. For example, some chips may switch a few nanoseconds earlier than others, leading to a higher thermal load in the earlier-switched chips. Consequently, individual semiconductor chips in a pulse inverter exhibit different peak temperatures during operation. With a homogeneously designed cooling system for the pulse inverter, this inevitably results in uneven wear of the individual semiconductor chips and thus a reduced lifespan for the pulse inverter.

[0004] To address the problem of reduced lifespan, it is known to incorporate thermal tolerances into the design of pulse inverters' thermal management systems. This allows for the mitigation of higher thermal loads on individual chips due to slight switching deviations. However, this approach requires a disproportionately high overall cooling capacity. Furthermore, the cooling systems typically need to be larger, which is disadvantageous in terms of both weight and installation space.

[0005] DE 10 2021 106 599 A1 discloses a liquid-cooled inverter for controlling an electric drive motor of a vehicle, EP 4 138 529 A1 discloses a lifetime-optimized cooling of semiconductors and DE 10 2017 207 178 A1 discloses a cooling device.

[0006] It is therefore the object of the present invention to at least partially overcome the disadvantages described above. In particular, it is the object of the present invention to provide a method and a system for the targeted adjustment of the cooling capacity of a cooling system for cooling a pulse inverter, which enables a particularly effective and energy-saving cooling operation of a cooling system of a pulse inverter and allows for a long service life of the pulse inverter.

[0007] The foregoing problem is solved by a method with the features of claim 1, a system with the features of claim 7, and a pulse inverter with the features of claim 8. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the system and the pulse inverter according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes, or can make, reciprocal references.

[0008] According to the invention, a method for the targeted adjustment of the cooling capacity of a cooling system for cooling a pulse inverter is provided. The method according to the invention comprises the steps of operating the pulse inverter in a test bench environment, determining the current operating temperature of the majority of semiconductor chips in the test bench environment using a sensor unit, determining the required cooling capacity for cooling the semiconductor chips based on the determined current operating temperature using a processing unit, and adjusting the cooling capacity of the cooling system based on the determined required cooling capacity of the majority of semiconductor chips using a control unit.

[0009] According to the invention, the method according to the invention, in particular by carrying out the steps according to the invention, is designed to enable a particularly effective and energy-saving cooling operation of a cooling system of a pulse inverter and thereby to guarantee a long service life of the pulse inverter.

[0010] According to the invention, it has been discovered that, based on temperature measurements of semiconductor chips in a pulse inverter during test bench operation, the cooling capacity of the individual semiconductor chips can be calibrated before the pulse inverter is installed. Depending on the measured temperature of the individual semiconductor chips, the cooling capacity of a cooling system can be variably adjusted for each chip so that semiconductor chips with higher measured temperatures in the test bench receive more cooling capacity than semiconductor chips with lower measured temperatures. Due to this one-time calibration of the cooling on the various chips, it is possible for all chips of a pulse inverter to essentially reach the same peak temperature during operation, with only minor deviations. This enables a long-lasting and high-performance operation of a pulse inverter with economical cooling.

[0011] Within the scope of the invention, a semiconductor chip can preferably be understood to be an electronic component or component made of a semiconductor material, such as an integrated circuit, in particular an electronic switch, such as a MOSFET, an IGBT, or a thyristor, capable of handling and switching large current and voltage values. Within the scope of the invention, a targeted adjustment of cooling capacity can preferably be understood as an adjustment that is not random but serves the specific purpose of solving the objective technical problem. According to the invention, a test bench operation can preferably be understood as an operation that simulates proper operation, e.g., the proper operation of a pulse inverter in an electric vehicle, as realistically as possible.The required cooling capacity can preferably be understood as the cooling capacity that must be dissipated from the individual semiconductor chips to ensure material-friendly operation, e.g., to adapt to a target temperature of < 50 °C, < 40 °C, or < room temperature. The method according to the invention can preferably be configured for adapting a cooling system of a pulse inverter used in an electrically powered motor vehicle, such as an electric vehicle or a hybrid vehicle.

[0012] It can be advantageous if determining the current operating temperature of semiconductor chips involves data processing, preferably including averaging and / or weighting of measured values, particularly averaging and / or weighting the current temperature of the semiconductor chips. Data processing can, in particular, increase the accuracy and reliability of the determined data. For example, when determining the current operating temperature of semiconductor chips by recording temperature measurements, temperature measurements can be taken at various locations on a semiconductor chip and / or at different measurement times, which can then be processed by averaging and / or weighting.

[0013] In order to precisely adapt the cooling capacity of the cooling system to the individual cooling requirements of each semiconductor chip, it can also be advantageous according to the invention (though not shown here) to determine the current operating temperature directly at the semiconductor chips. By measuring the temperature directly at the semiconductor chips, it is possible to determine the current operating temperature of the semiconductor chips and, accordingly, the required cooling capacity for each individual semiconductor chip very precisely.

[0014] With a view to a structurally simple method for adapting the cooling capacity of a cooling system to the individual cooling requirements of individual semiconductor chips embedded within a mold material, the current operating temperature near the semiconductor chips is determined. The required cooling capacity for cooling the semiconductor chips is then determined based on this determined operating temperature near the semiconductor chips by means of an additional calculation. This additional calculation preferably includes determining the thermal conductivity within the mold material. According to the invention, determining the current operating temperature near a semiconductor chip can preferably be understood as a temperature measurement that is not performed directly on the surface of the semiconductor chips, but rather, for example, on the surface of a mold layer in which a semiconductor chip is embedded.

[0015] Furthermore, for a quick and simple targeted adjustment of the cooling system's cooling capacity, it is conceivable that the required cooling capacity for the semiconductor chips could be determined by comparison with reference values, preferably based on empirical data from similar cooling systems used to cool pulse inverters. Thus, for similar pulse inverters with similar cooling systems, a known and proven targeted adjustment of the cooling system's capacity can be made upon detection of a temperature difference between individual semiconductors.

[0016] With a view to quickly and easily adjusting the cooling capacity of the cooling system, it is also conceivable that determining the required cooling capacity and / or adjusting the cooling capacity of the cooling system is carried out jointly for several semiconductor chips. In determining the required cooling capacity, preferably an average temperature of the majority of semiconductor chips is used, and / or the group of several semiconductor chips is adjusted to the same temperature. In this way, in particular, a region-specific adjustment of the cooling capacity to a temperature load can be carried out.

[0017] In this context, it can advantageously be further provided that, within the framework of a quick and simple targeted adjustment of the cooling performance of the cooling system, the grouping comprises a summary of the semiconductor chips into a group of at least four semiconductor chips, preferably a summary into a group of all semiconductor chips of the pulse inverter.

[0018] With a view to a structurally simple yet effective targeted adjustment of the cooling capacity of the cooling system, it is advantageously further provided according to the invention that the adjustment of the cooling capacity of the cooling system is achieved by adjusting the flow rate of a cooling medium and / or by changing a cooling sequence. Adjusting the flow rate of a cooling medium can, for example, be achieved by adjusting the diameter of one or more cooling channels. Changing a cooling sequence can also be achieved by introducing cooling fluid guide structures. The mandatory and optional steps of the method according to the invention can be at least partially automated, e.g., sensor-controlled. It is also conceivable that individual, several, or all steps of the method according to the invention can be implemented via a computer.

[0019] The invention also relates to a system for the targeted adjustment of the cooling capacity of a cooling system for cooling a pulse inverter with a plurality of semiconductor chips, preferably for carrying out a method described above, comprising a test bench for operating the pulse inverter in test bench mode, a sensor unit for determining the current operating temperature of the plurality of semiconductor chips in test bench mode, a processing unit for determining the required cooling capacity for cooling the semiconductor chips, and a control unit for adjusting the cooling capacity of the cooling system based on the determined required cooling capacity of the plurality of semiconductor chips. The system according to the invention thus offers the same advantages as those already described in detail with regard to the method according to the invention.

[0020] The invention also relates to a pulse inverter comprising a plurality of semiconductor chips and a cooling system for cooling the pulse inverter, wherein the cooling capacity of the cooling system was specifically adapted by means of a method described above, preferably using a system described above. Thus, the pulse inverter according to the invention offers the same advantages as those already described in detail with regard to the method and system according to the invention. The semiconductor chips of the pulse inverter can be either freely accessible or at least partially embedded in a mold material.

[0021] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.

[0022] They show schematically: Fig. 1 the individual steps of a method according to the invention for the targeted adjustment of a cooling capacity of a cooling system for cooling a pulse inverter according to a first embodiment, Fig. 2 a system according to the invention for the targeted adjustment of a cooling power of a cooling system for cooling a pulse inverter according to a first embodiment.

[0023] Fig. Figure 1 shows the individual steps of a method according to the invention for the targeted adjustment of a cooling capacity of a cooling system 2 for cooling a pulse inverter 6 according to a first embodiment.

[0024] As per Fig. As can be seen in Figure 1, the method according to the invention comprises the steps of operating 100 of the pulse inverter 6 in a test bench operation, determining 200 a current operating temperature of the majority of semiconductor chips 4 in the test bench operation by means of a sensor unit 20, determining 300 a required cooling power for cooling the semiconductor chips 4 on the basis of the determined current operating temperature by means of a processing unit 22, and adjusting 400 the cooling power of the cooling system 2 on the basis of the determined required cooling power of the majority of semiconductor chips 4 by means of a control unit 24.

[0025] The determination of the current operating temperature can advantageously be carried out directly at the semiconductor chips 4.

[0026] Likewise, the determination of a current operating temperature 200 - e.g. for semiconductor chips 4 embedded in a mold material 18 - can also be carried out in the vicinity of the semiconductor chips 4, wherein a determination 300 of the required cooling power for cooling the semiconductor chips 4 on the basis of the determined current operating temperature in the vicinity of the semiconductor chips 4 can preferably be carried out by an additional calculation, wherein the additional calculation in particular includes a determination of a heat conduction within a mold material 18.

[0027] Determining 300 a required cooling capacity and / or adjusting 400 the cooling capacity of the cooling system 2 can also advantageously be carried out in a grouped manner for several semiconductor chips 4 together, wherein, within the scope of determining 300 a required cooling capacity, preferably an average temperature of the majority of semiconductor chips 4 is used for the determination 300 and / or the group of several semiconductor chips 4 is adjusted to the same temperature.

[0028] The grouping can, for example, comprise a summary of the semiconductor chips 4 into a group of at least four semiconductor chips 4, or preferably a summary into a group of all semiconductor chips 4 of the pulse inverter 6.

[0029] Fig. Figure 2 shows a system 1 according to the invention for the targeted adjustment of a cooling power of a cooling system 2 for cooling a pulse inverter 6 with a plurality of semiconductor chips 4 according to a first embodiment.

[0030] As per Fig. As can be seen in Figure 2, the system 1 according to the invention comprises a test bench P for operating 100 the pulse inverter 6 embedded in a mold material 18 in a test bench operation, a sensor unit 20 with two temperature sensors 16 for determining 200 a current operating temperature of the majority of semiconductor chips 4 in the test bench operation, a processing unit 22 for determining 300 a required cooling power for cooling the semiconductor chips 4 and a control unit 24 for adjusting 400 the cooling power of the cooling system 2 on the basis of the determined required cooling power of the majority of semiconductor chips 4.

[0031] As per Fig.2 further shows that the pulse inverter 6 has a cable connection 14 for connecting some semiconductor chips 4 as well as a layer structure consisting of a ceramic layer 8, a solder layer 10 and a base plate 12, which is arranged here between the cooling system 2 and the semiconductor chips 4.

[0032] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention.

Claims

[1] Method for the targeted adjustment of a cooling capacity of a cooling system (2) for cooling a pulse inverter (6) with a plurality of semiconductor chips (4), comprising the steps: - operating (100) the pulse inverter (6) in a test bench operation, - determining (200) a current operating temperature of the plurality of semiconductor chips (4) in the test bench operation by means of a sensor unit (20), - determining (300) a required cooling power for cooling the semiconductor chips (4) on the basis of the determined current operating temperature by means of a processing unit (22), - adjusting (400) the cooling power of the cooling system (2) on the basis of the determined required cooling power of the plurality of semiconductor chips (4) by means of a control unit (24), wherein the determination (200) of a current operating temperature in the vicinity of the semiconductor chips (4) is carried out, wherein a determination (300) of the required cooling power for cooling the semiconductor chips (4) on the basis of the determined current operating temperature in the vicinity of the semiconductor chips (4) is carried out by an additional calculation. [2] Method according to claim 1, characterized by that determining (200) a current operating temperature of the semiconductor chips (4) comprises carrying out data processing. [3] Method according to one of the preceding claims, characterized by that the determination (300) of a required cooling power for cooling the semiconductor chips (4) is carried out on the basis of a comparison with comparison values. [4] Method according to one of the preceding claims, characterized by that the determination (300) of a required cooling power and / or the adaptation (400) of the cooling power of the cooling system (2) is carried out jointly for a plurality of semiconductor chips (4). [5] Method according to claim 4, characterized by that the grouping comprises a combination of the semiconductor chips (4) into a group of at least four semiconductor chips (4). [6] Method according to one of the preceding claims, characterized by that the adjustment (400) of the cooling capacity of the cooling system (2) is carried out by adjusting a flow rate of a cooling medium and / or by changing a cooling sequence. [7] System (1) for the targeted adjustment of a cooling capacity of a cooling system (2) for cooling a pulse inverter (6) with a plurality of semiconductor chips (4) for carrying out a method according to one of the preceding claims, comprising: - a test bench (P) for operating (100) the pulse inverter (6) in a test bench mode, - a sensor unit (20) for determining (200) a current operating temperature of the plurality of semiconductor chips (4) in the test bench operation, - a processing unit (22) for determining (300) a required cooling power for cooling the semiconductor chips (4), - a control unit (24) for adjusting (400) the cooling capacity of the cooling system (2) on the basis of the determined required cooling capacity of the plurality of semiconductor chips (4). [8] Pulse inverter (6) with a plurality of semiconductor chips (4) and a cooling system (2) for cooling the pulse inverter (6), characterized by that the cooling capacity of the cooling system (2) was adjusted in a targeted manner by means of a method according to one of claims 1 to 6 using a system (1) according to claim 7.

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