DE102018107513A1 - Method for operating a cooling arrangement - Google Patents

Abstract

Method for operating a cooling arrangement (1) for at least one electrical component (2), wherein the cooling arrangement (1) at least one of a cooling fluid (3) acted upon cooling body (4), a heat exchanger (5) and the heat sink (4) and the heat exchanger (5) connecting supply line (6) for the cooling fluid (3), wherein the heat sink (4) for cooling the at least one electrical component (2) is provided, wherein the heat exchanger (5) upstream of the heat sink (4) is; wherein the cooling fluid (3) has a previously known evaporation temperature (7); wherein the cooling fluid (3) is heated upstream of the heat sink (4) in the heat exchanger (5).

Description

The invention relates to a method for operating a cooling arrangement. The cooling arrangement is provided for cooling at least one electrical component, for. B. a power electronics of a motor vehicle.

For electrical components, it is possible to use cooling fluids in which the cooling effect is realized by a phase transition of the cooling fluid (that is to say, for example, from liquid to gaseous). An advantage of such a configuration is that a large heat transfer between the evaporating cooling fluid and the heat sink provided for cooling the electrical component can be realized. Furthermore, an isothermal evaporation of the cooling fluid can be realized.

Due to the constant temperature of the evaporating cooling fluid arise no (significant) temperature differences in the electrical component to be cooled, so that the life of the electrical component can be extended.

However, a problem is a hypothermia of the cooling fluid. In this case, in the heat supply from the electrical component to the cooling fluid first, a heating of the liquid cooling fluid, initially without its evaporation instead. In this case, the heat transfer decreases and there is a temperature change to the evaporation temperature of the cooling fluid instead. The advantage of cooling with the evaporating cooling fluid is then at least limited or canceled.

The object of the present invention is at least partially to solve the problems mentioned with reference to the prior art. In particular, a method for operating a cooling arrangement is to be proposed, by which the most uniform possible cooling of an electrical component is made possible.

To solve these problems, a method with the features according to claim 1 contributes. Advantageous developments are the subject of the dependent claims. The features listed individually in the claims can be combined in a technologically meaningful manner and can be supplemented by explanatory facts from the description and / or details of the figures, with further embodiments of the invention are shown.

1. a) Erhöhen einer Temperatur des Kühlfluids durch den Wärmeübertrager auf eine erste Temperatur, die höchstens der Verdampfungstemperatur entspricht, wobei das Kühlfluid nach der Erhöhung der Temperatur in einem flüssigen ersten Zustand vorliegt;
2. b) Leiten des Kühlfluids über die Zuleitung zu dem Kühlkörper und Überführen zumindest eines Teils des Kühlfluids in einen dampfförmigen zweiten Zustand.

A method for operating a cooling arrangement is proposed. The cooling arrangement is associated with at least one electrical component, for. B. a power electronics of a motor vehicle. The cooling arrangement has at least one cooling body acted upon by a cooling fluid, a heat exchanger and a supply line for the cooling fluid connecting the cooling body and the heat exchanger. The (at least one) heat sink is provided for cooling the at least one electrical component (that is, for example, arranged in the immediate vicinity and / or in heat-conducting connection to the at least one electrical component). The heat exchanger is arranged upstream of the heat sink. The cooling fluid (eg, water or glycol, or the like) has a known evaporation temperature. The method comprises at least the following steps:

1. a) increasing a temperature of the cooling fluid through the heat exchanger to a first temperature which corresponds at most to the evaporation temperature, wherein the cooling fluid is in a liquid first state after the increase in temperature;
2. b) passing the cooling fluid through the supply line to the heat sink and transferring at least a portion of the cooling fluid into a vaporous second state.

The proposed method involves heating the cooling fluid upstream of the heat sink. In particular, the cooling fluid is heated as close as possible to the previously known (under the existing ambient conditions, ie, for example, pressure, etc.) evaporation temperature. In particular, it is ensured that the cooling fluid is still in a liquid state. However, a partial evaporation can take place, whereby the efficiency of the cooling would be reduced on the one hand, on the other hand, a supercooling of the cooling fluid can be prevented with greater certainty. The evaporation of the cooling fluid should then take place on or in the heat sink, wherein the heating of the cooling fluid should be effected as close as possible to the evaporation temperature as immediate as possible evaporation of the cooling fluid after acting on the heat sink. In this way, the cooling of the heat sink or of the electrical component which is as homogeneous as possible can be achieved (ie the lowest possible temperature difference over the surface of the electrical component cooled by the heat sink).

In particular, the first temperature is at most 5 Kelvin, preferably at most 2 Kelvin below the evaporation temperature.

Particularly preferably, the first temperature is at most 1 Kelvin below the evaporation temperature.

The heat exchanger can in particular any form of a heater for the cooling fluid include (eg, an electric heater, a heat exchanger, etc.).

In particular, the heat exchanger is additionally connected to the heat sink via a return line. In the heat exchanger, the cooling fluid to be heated and flowing to the supply line is heated by the cooling fluid supplied to the heat exchanger via the return line. As a heat exchanger DC heat exchanger (cooling fluid in the supply line has substantially the same flow direction as cooling fluid in the return line within the heat exchanger) or countercurrent heat exchanger (cooling fluid in the supply line has within the heat exchanger substantially the opposite flow direction as cooling fluid in the return line) become.

In particular, at least the supply line between the at least one heat sink and the heat exchanger with respect to an environment designed to be thermally insulated, so that a renewed cooling of the cooling fluid is prevented as much as possible. In particular, a cooling of the cooling fluid takes place during the flow through the supply line and during normal operation of the cooling arrangement by at most 1 Kelvin.

According to another embodiment, the supply line is designed to be heatable. In particular, an electric heater is provided, via which the cooling fluid flowing through the supply line can be heated.

In particular, a cooling of the cooling fluid during the flow through the supply line and during normal operation of the cooling arrangement can be completely prevented. Possibly. is also possible further heating of the cooling fluid in the supply line.

In particular, the heat exchanger can also be arranged directly adjacent to the heat sink, so that the supply line is omitted as a line with a certain length. The supply line designates in particular only the fluidic connection between heat exchanger and heat sink.

In particular, the cooling arrangement is controlled by a control unit, wherein a mass flow of the cooling fluid is controlled so that the cooling fluid immediately downstream of the heat sink has a second temperature which is at most 5 Kelvin, preferably at most 2 Kelvin above the evaporation temperature.

Preferably, the cooling arrangement is controlled by a control unit, wherein a mass flow of the cooling fluid is regulated as a function of at least one operating parameter of the at least one electrical component.

In particular, a heat output of the at least one electrical component is calculated as a function of the at least one operating parameter.

An operating parameter is z. As an applied voltage to the electrical component, a component flowing through the electrical current, a duration of exposure to electrical energy, etc. In particular, the heat development of the electrical component can be determined or even predicted on the at least one operating parameter.

In particular, the mass flow (also anticipated, ie anticipating a required higher cooling capacity) can be regulated via the control unit so that heating of the heat sink (or heating of the electrical component) can be at least largely prevented.

The at least one electrical component can be used to provide an electrical drive power of a motor vehicle, wherein the at least one operating parameter changes depending on an operation of the motor vehicle.

Furthermore, a cooling arrangement is proposed for at least one electrical component, at least comprising a cooling body acted upon by a cooling fluid, which is provided for cooling the at least one electrical component, a heat exchanger arranged upstream of the cooling body, and a supply line connecting the cooling body and the heat exchanger. The cooling arrangement can be operated by the method already described.

Further, a drive train for a motor vehicle is proposed, at least comprising an electrical component which can be used to provide an electrical drive power of the motor vehicle. The drive train has the described cooling arrangement for at least the one electrical component.

Furthermore, a motor vehicle is proposed, at least with the described drive train, which in particular comprises a drive unit for driving the motor vehicle.

The remarks on the method are particularly applicable to the drive train and the motor vehicle and vice versa.

By way of precaution, it should be noted that the numerical terms used here ("first", "second",...) Primarily (only) serve to distinguish a plurality of similar objects, variables or processes, ie in particular no dependence and / or order of these objects, quantities or mandate processes to one another. Should a dependency and / or order be required, this is explicitly stated here or it obviously follows for the person skilled in the art when studying the concretely described embodiment.

The invention and the technical environment will be explained in more detail with reference to the accompanying figure. It should be noted that the invention should not be limited by the stated embodiment. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figure and to combine them with other components and findings from the present description. In particular, it should be noted that the figure and in particular the illustrated proportions are only schematic. 1 shows a motor vehicle 16 ,

The car 16 includes a powertrain 17 that is an electrical component 2 having, for providing an electrical drive power of the motor vehicle 16 can be used. The powertrain 17 has a cooling arrangement 1 for the electrical component 2 on. The cooling arrangement 1 includes a pump 18 for conveying the fluid 3 through the cooling arrangement

The cooling arrangement 1 is the electrical component 2 assigned. The cooling arrangement 1 has one of a cooling fluid 3 acted upon heat sink 4 , a heat exchanger 5 and a heat sink 4 and the heat exchanger 5 connecting supply line 6 for the cooling fluid 3 on. The (at least one) heat sink 4 is for cooling the electrical component 2 provided (ie in the immediate vicinity and in heat-conducting connection to the electrical component 2 arranged). The heat exchanger 5 is upstream of the heat sink 4 and the supply line 6 arranged. The cooling fluid 3 (eg, water or glycol, or the like) has a known evaporation temperature 7 on. According to step a) of the method, a temperature of the cooling fluid 3 through the heat exchanger 5 to a first temperature 8th increased, the maximum of the evaporation temperature 7 corresponds, wherein the cooling fluid 3 after raising the temperature in a liquid first state 9 is present.

In step b) of the process, the cooling fluid 3 over the supply line 6 to the heat sink 4 passed and at least a portion of the cooling fluid 3 (or the whole of the heat sink 4 contacting cooling fluid 3 ) in a vaporous second state 10 transferred.

The method includes heating the cooling fluid 3 upstream of the heat sink 4 , The cooling fluid 3 is as close as possible to the (under the existing environmental conditions, ie, for example, pressure, etc.) previously known evaporation temperature 7 heated. This ensures that the cooling fluid 3 still in a liquid first state 9 is present. The evaporation of the cooling fluid 3 should then on or in the heat sink 4 carried out, whereby by the heating of the cooling fluid 3 close to the evaporation temperature 7 a possible immediate evaporation of the cooling fluid 3 after exposure to the heat sink 4 should be done. This allows the most homogeneous possible cooling of the heat sink 4 or the electrical component 2 be achieved (ie the lowest possible temperature difference over the through the heat sink 4 cooled surface of the electrical component 2 ).

The heat exchanger 5 is with the heat sink 4 additionally via a return line 11 connected. In the heat exchanger 5 is the to be heated and the supply line 6 flowing cooling fluid 3 through the heat exchanger 5 over the return line 11 supplied cooling fluid 3 heated.

The cooling arrangement 1 is via a control unit 12 regulated, being a mass flow 13 of the cooling fluid 3 is regulated so that the cooling fluid 3 immediately downstream of the heat sink 4 a second temperature 14 which is just above the evaporation temperature 7 is or even the evaporation temperature 7 equivalent.

The cooling arrangement 1 can via the control unit 12 be regulated so that a mass flow 13 of the cooling fluid 3 depending on at least one operating parameter 15 the electrical component 2 is regulated.

LIST OF REFERENCE NUMBERS

1

cooling arrangement

2

component

3

cooling fluid

4

heatsink

5

Heat exchanger

6

supply

7

Evaporation temperature

8th

first temperature

9

first condition

10

second state

11

return

12

control unit

13

mass flow

14

second temperature

15

operating parameters

16

motor vehicle

17

powertrain

18

pump

Claims (10)

Method for operating a cooling arrangement (1) for at least one electrical component (2), wherein the cooling arrangement (1) at least one of a cooling fluid (3) acted upon cooling body (4), a heat exchanger (5) and the heat sink (4) and the heat exchanger (5) connecting supply line (6) for the cooling fluid (3), wherein the heat sink (4) for cooling the at least one electrical component (2) is provided, wherein the heat exchanger (5) upstream of the heat sink (4) is; wherein the cooling fluid (3) has a previously known evaporation temperature (7); the method comprising at least the following steps: a) increasing a temperature of the cooling fluid (3) through the heat exchanger (5) to a first temperature (8) which corresponds at most to the evaporation temperature (7), the cooling fluid (3) after the temperature being raised in a liquid first state (8) 9) is present; b) passing the cooling fluid (3) via the supply line (6) to the heat sink (4) and transferring at least a portion of the cooling fluid (3) into a vaporous second state (10). Method according to Claim 1 , wherein the first temperature (8) is at most 5 Kelvin below the evaporation temperature (7). Method according to one of the preceding claims, wherein the first temperature (8) is at most 1 Kelvin below the evaporation temperature (7). Method according to one of the preceding claims, wherein the heat exchanger (5) with the heat sink (4) is additionally connected via a return line (11); wherein in the heat exchanger (5) to be heated and the supply line (6) flowing cooling fluid (3) by the heat exchanger (5) via the return line (11) supplied cooling fluid (3) is heated. Method according to one of the preceding claims, wherein the cooling arrangement (1) via a control unit (12) is controlled, wherein a mass flow (13) of the cooling fluid (3) is controlled so that the cooling fluid (3) immediately downstream of the heat sink (4) a second temperature (14) which is at most 5 Kelvin above the evaporation temperature (7). Method according to one of the preceding claims, wherein the cooling arrangement (1) is controlled by a control unit (12), wherein a mass flow (13) of the cooling fluid (3) in dependence on at least one operating parameter (15) of the at least one electrical component (2) is regulated. Method according to Claim 6 wherein a heat output of the at least one electrical component (2) is calculated as a function of the at least one operating parameter (15). Method according to one of the preceding Claims 6 and 7 wherein the at least one electrical component (2) is used for providing an electrical drive power of a motor vehicle (16), wherein the at least one operating parameter (15) changes in dependence on an operation of the motor vehicle (16). Cooling arrangement (1) for at least one electrical component (2), comprising at least one of a cooling fluid (3) acted upon cooling body (4), which is provided for cooling the at least one electrical component (2), one upstream of the heat sink (4) Heat exchanger (5) and a the heat sink (4) and the heat exchanger (5) connecting the supply line (6); wherein the cooling arrangement (1) is operable by the method according to one of the preceding claims. Drive train (17) for a motor vehicle (16), at least comprising an electrical component (2) which can be used to provide an electrical drive power of the motor vehicle (16); wherein the drive train (17) a cooling arrangement (1) according to Claim 9 for at least the one electrical component (2).

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