Device and method for ascertaining coolant temperature of cooling circuit

Abstract

The invention relates to a device (100) for determining a coolant temperature of a cooling circuit (300), said cooling circuit (300) being designed to sequentially cool power electronics of at least a first and a second electrical component (510, 520). The device (100) is designed, during operation of the first component (510), to receive and evaluate a signal characterizing the temperature of the power electronics of the switched-off second component (520) in order to ascertain the coolant temperature of the cooling circuit (300), and, during operation of the second component (520), to evaluate the temperature of the power electronics of the switched-off second component (520) in order to ascertain the coolant temperature of the cooling circuit (300). In order to ascertain the coolant temperature of the cooling circuit (300), a signal characterizing the temperature of the power electronics of the switched-off first component (510) is received and evaluated.

Description

Technical Field

[0001] The invention relates to a device and a method for ascertaining the coolant temperature of a cooling circuit. The invention also relates to an electrical system, a drive train with the device, a vehicle with the drive train, and a computer program and a machine-readable storage medium. Background Art

[0002] Preferably, power electronic devices in a vehicle, such as, for example, charging devices, DC voltage converters, inverters and / or motors, generate waste heat during operation, and the waste heat is led away from the heat source by means of the coolant of the cooling circuit. Preferably, the heat source is a component of power electronics, preferably a power switch. The corresponding implementation scheme is known from the open document WO 2017 / 182226 A1. In order to reliably operate such power electronic devices at their power limits, the temperature of the coolant must be known. If the coolant temperature exceeds a predetermined threshold, the waste heat can no longer be fully led away due to the heated coolant. As a result, the device is cut off or the power currently implemented is reduced to such an extent that the coolant temperature drops again and the cooling of the power electronic components can be achieved again. In order to determine the coolant temperature, a temperature sensor for obtaining the temperature is arranged at the cooling circuit or in the coolant. In order to reduce the structural space required for the temperature sensor, there is a need for a solution for obtaining the coolant temperature, which can achieve the obtaining of the coolant temperature without a temperature sensor correspondingly arranged at the cooling circuit. Summary of the invention

[0003] A device for determining the coolant temperature of a cooling circuit is provided. The cooling circuit is designed to cool the power electronics of at least a first and a second power and electrical component in sequence. The first component includes a first sensor device for determining the temperature of the power electronics of the first component. The second component includes a second sensor device for determining the temperature of the power electronics of the second component. The first component is at least temporarily connected and its power electronics generate waste heat. At the same time, the second component is turned off. The device is configured to receive and evaluate a signal representing the temperature of the power electronics of the turned-off second component in order to determine the coolant temperature of the cooling circuit during operation of the first component, and to receive and evaluate a signal representing the temperature of the power electronics of the turned-off first component in order to determine the coolant temperature of the cooling circuit during operation of the second component.

[0004] Preferably, the coolant temperature is the temperature of the coolant in the cooling circuit, preferably the average temperature of the coolant in the cooling circuit. Preferably, the cooling circuit includes a closed pipeline system, through which a cooling medium, a cooling fluid or a coolant flows, wherein the coolant flows through a heat exchanger and is cooled therein. Subsequently, the coolant flows through one another at the heat source and is heated again here so as to be cooled again by the heat exchanger. Preferably, the heat source or the power and electrical component is a structural component or an apparatus of each power electronics, which preferably generates waste heat during its operation when it is connected, and the waste heat is led away by the coolant flowing through. When the power and electrical component is turned off, it is preferably not in operation and does not generate waste heat. The first and second power and electrical components can be arranged in their own housings, or preferably in a common housing, preferably with a spatial spacing on a common or multiple printed circuit boards. The corresponding power and electrical component includes a sensor device for obtaining the temperature of its power and electronic components in order to control it, preferably a power switch, a capacitor, a choke or a winding of an electric motor. Preferably, the sensor device is arranged in close proximity to the power electronic device of the component in order to determine the temperature of the power electronic device of the component, and can accurately determine the temperature of the power electronic device of the component. Preferably, the power electronic device is connected to the cooling circuit in a very good thermally conductive manner. Therefore, when the power electronic device is not running or preferably continuously shut down, the power electronic device quickly increases the temperature of the coolant. In order to determine the coolant temperature, a signal representing the temperature of the shut-off power and electrical component is received and evaluated by the device or a control device within the device. Preferably, the signal of the sensor device of the shut-off component or the shut-off component is received and evaluated. The greater the distance between the sensor device considered for determining the coolant temperature and the actual heat source, the more accurately the actual coolant temperature of the cooling circuit can be determined. In the area of ​​the sensor device to be considered, the influence of the heat source on the coolant temperature decreases as the distance between the heat source and the sensor device to be considered increases. Preferably, the coolant temperature is determined when evaluating the signal. Preferably, the coolant temperature is determined from the received signal by means of a calculation model. Preferably, the calculation model considered reflects the heat transfer from the sensor device to the coolant. Preferably, if the coolant temperature exceeds a predeterminable threshold value and the waste heat can no longer be removed sufficiently due to the warmed coolant, at least one component is switched off or its currently implemented power is reduced to such an extent that the coolant temperature drops again and cooling of the power electronic components is possible again. Alternatively, the volume flow of the coolant is preferably increased or the coolant temperature is reduced by increasing the cooling power of a heat exchanger located in the cooling circuit.

[0005] Advantageously, a simple device is provided which determines the coolant temperature of a cooling circuit. No additional components or installation space are required for this solution.

[0006] In another embodiment, the first component is a charger and the power electronics of the first component include a power switch. Preferably, the first component is a charger for a vehicle, which is used to charge a high-voltage battery that can be connected on the output side. Preferably, a first sensor device for determining the temperature of the power electronics of the first component is arranged in close proximity to the power switch of the charger and can accurately determine the temperature of the power switch of the charger. Preferably, the power switch, IGBT or MOSFET is connected to the cooling circuit in a very good thermally conductive manner. Therefore, when the power switch is not in operation or is preferably continuously turned off, the power switch quickly increases the temperature of the coolant.

[0007] A configuration of the first power electrical component is advantageously provided.

[0008] In another embodiment, the second component is a DC voltage converter or an inverter. The power electronic device of the second component includes a power switch. Preferably, the second component is a DC voltage converter, which is used to convert the high voltage of the high-voltage battery into a low voltage for supplying the vehicle's onboard power system. Preferably, the second sensor device for determining the temperature of the power electronic device of the second component is arranged in close proximity to the power switch of the DC voltage converter and can accurately determine the temperature of the power switch of the DC voltage converter. Preferably, the power switch, IGBT or MOSFET is connected to the cooling circuit in a very good thermally conductive manner. Therefore, when the power switch is not running or preferably continuously turned off, the power switch quickly increases the temperature of the coolant.

[0009] Advantageously, a configuration of the second power electrical component is provided.

[0010] In addition, an electrical system is provided, which comprises at least a first and a second power electronic component, a common cooling circuit for sequentially cooling the power electronic components of the first and second components, and a device for determining the coolant temperature of the cooling circuit. The first component comprises a first sensor device for determining the temperature of the power electronic components of the first component, and the second component comprises a second sensor device for determining the temperature of the power electronic components of the second component. The first component is at least temporarily switched on and its power electronic components generate waste heat and the second component is switched off at the same time, or vice versa. The device is configured to receive and evaluate a signal representing the temperature of the power electronic components of the switched off second component in order to determine the coolant temperature of the cooling circuit during the operation of the first component, and to receive and evaluate a signal representing the temperature of the power electronic components of the switched off first component in order to determine the coolant temperature of the cooling circuit during the operation of the second component.

[0011] Advantageously, an electrical system is provided which determines the coolant temperature of the cooling circuit. No additional components or installation space are required for this solution.

[0012] The invention further relates to a drive train having a device as described above, wherein the drive train comprises in particular a high-voltage battery, an inverter and / or an electric machine. Advantageously, a device for determining the coolant temperature of a cooling circuit is provided for the drive train of an electric vehicle. No additional components or installation space are required for this solution.

[0013] The invention further relates to a vehicle having a drive train as described above.

[0014] Advantageously, a device is provided for the vehicle to determine the coolant temperature of the cooling circuit. No additional components or installation space are required for this solution.

[0015] The invention furthermore relates to a method for operating a device as envisaged above, the method comprising the steps of:

[0016] During operation of the first component, a signal is received that represents the temperature of the power electronic device of the shut-down second power electronic device; the received signal is evaluated, and during operation of the second component, a signal is received that represents the temperature of the power electronic device of the shut-down first power electronic device; the received signal is evaluated (820).

[0017] Advantageously, a method for ascertaining the coolant temperature of the cooling circuit is provided by means of the acquisition and evaluation of the signal. No additional components or installation space are required for this solution.

[0018] Furthermore, the invention relates to a computer program which comprises commands which, when the program is executed, cause the device to carry out the described method.

[0019] Furthermore, the invention relates to a machine-readable storage medium which comprises commands which, when executed, cause the device to carry out the described method.

[0020] It goes without saying that the features, properties and advantages of the device are correspondingly applicable or can be used for the electrical system and the method or the drive train and the vehicle, and vice versa.

[0021] Further features and advantages of embodiments of the present invention will become apparent from the following description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will be explained in more detail below with reference to some drawings, in which:

[0023] Figure 1A schematically illustrated vehicle is shown having a drive train having a device,

[0024] Figure 2 A schematically illustrated flow chart of a method for operating the device is shown. DETAILED DESCRIPTION

[0025] Figure 1 A schematically illustrated vehicle 700 is shown having a drive train 600 with a device 100 and an exemplary electrical system 500. The vehicle 700 is shown here only as having four wheels, wherein the present invention can also be used for any vehicle with any number of wheels on land, water and in the air. The schematically illustrated drive train 600 comprises at least the device 100. The drive train preferably also comprises a first and a second electrical power component 510, 520 or an electrical system 500 with a cooling circuit 300, a battery 470, an inverter 472 and / or an electric motor 474. The device 100 is configured to determine the coolant temperature of the coolant in the cooling circuit 300. The cooling circuit 300 is designed to sequentially cool the power electronics of at least the first and second electrical power components 510, 520. For the sake of clarity, in Figure 1Only a part of the cooling circuit 300 is shown in FIG. The cooling circuit is preferably a closed system in which the coolant flows and circulates in one direction. The first component 510 includes a first sensor device 512, which is used to obtain the temperature of the power electronic device of the first component 510. By way of example, the first component 510 is shown as a charging device, which preferably has an input connection 514 for connecting a single-phase or multi-phase AC voltage source, so as to charge a battery or a high-voltage battery 470 that can be connected on the output side. Preferably, the battery is charged by means of an AC voltage source when the vehicle is stopped. The second component 520 includes a second sensor device 522, which is used to obtain the temperature of the power electronic device of the second component 520. By way of example, the second component 520 is shown as a DC voltage converter, which preferably has a low-voltage connection 524, and the vehicle's onboard power system and the low-voltage battery are preferably connected to the low-voltage connection. By means of the DC voltage converter, energy from the high-voltage power system or the high-voltage battery is preferably supplied to the vehicle's onboard power system, wherein the high-voltage input voltage is converted into the low voltage of the vehicle's onboard power system. Preferably, the supply to the low-voltage grid is realized by means of a DC voltage converter during the driving of the vehicle. Therefore, preferably, the first component 510 is switched on and the second component 520 is switched off during the vehicle stop, and the first component 510 is switched off and the second component 520 is switched on during the driving of the vehicle. Therefore, the first component 510 is switched on at least temporarily and its power electronics generate waste heat and the second component 520 is switched off at the same time, and vice versa. The device 100 is configured to receive and evaluate a signal representing the temperature of the power electronics of the switched-off second component 520 in order to determine the coolant temperature of the cooling circuit 300 during the operation of the first component 510. In addition, the device 100 is configured to receive and evaluate a signal representing the temperature of the power electronics of the switched-off first component 510 in order to determine the coolant temperature of the cooling circuit 300 during the operation of the second component 520. Preferably, the device 100 receives the signal directly from one of the components or via a bus system in a wired manner, and wireless transmission of the signal is also possible. The signal is preferably a signal of a sensor device, and further processed signals characterizing the temperature of the power electronic device of the shut-down power electronic device are also feasible. Preferably, the coolant temperature is determined when evaluating the signal. The evaluation of the signal preferably includes the direct further use of the signal or includes the following evaluation, which can include filtering, offset shifting, use or other steps of processing the signal of the calculation model. The electrical system 500 includes at least first and second power electronic components 510, 520, a common cooling circuit 300 for sequentially cooling the power electronic devices of the first and second components 510, 520, preferably a common cooling circuit section, and a device 100 for determining the coolant temperature of the cooling circuit 300. By way of example, the electrical system 500 is shown as a combination of a charging device and a DC voltage converter preferably within a housing.

[0026] Figure 2 A schematically illustrated flow chart of a method 800 for operating the device 100 is shown. The method 800 begins with step 805. In step 810, a signal is received that characterizes the temperature of the power electronic component of the switched-off power electronic component. In step 820, the received signal is evaluated. Preferably, the coolant temperature is ascertained during the evaluation of the signal. The method ends with step 825.

Claims

1. A device (100) for determining the coolant temperature of a cooling circuit (300), in, The cooling circuit (300) is designed to sequentially cool power electronic components of at least a first and a second power electrical component (510, 520), The first component (510) comprises a first sensor device (512) for determining the temperature of a power electronic device of the first component (510), and the second component (520) comprises a second sensor device (522) for determining the temperature of a power electronic device of the second component (520), wherein the first component (510) is at least temporarily switched on and its power electronics generate waste heat and the second component (520) is simultaneously switched off, or vice versa, It is characterized in that The device (100) is configured to: During operation of the first component (510), a signal characterizing the temperature of a power electronic component of a switched-off second component (520) is received and evaluated in order to determine the coolant temperature of the cooling circuit (300), Furthermore, during operation of the second component (520), a signal characterizing the temperature of the power electronics of the switched-off first component (510) is received and evaluated in order to determine the coolant temperature of the cooling circuit (300).

2. The device according to claim 1, wherein The first component (510) is a charging device and the power electronics of the first component (510) include a power switch.

3. The device according to any one of the preceding claims, wherein: The second component (520) is a DC voltage converter or inverter (472) and the power electronics of the second component (520) include power switches.

4. An electrical system (500) comprising at least a first and a second power electronic component (510, 520), a common cooling circuit (300) for sequentially cooling the power electronic components of the first and second components (510, 520), and a device (100) for determining a coolant temperature of the cooling circuit (300), in, The first component (510) comprises a first sensor device (512) for determining the temperature of a power electronic component of the first component (510), and the second component (520) comprises a second sensor device (522) for determining the temperature of a power electronic component of the second component (520), wherein the first component (510) is at least temporarily switched on and its power electronics generate waste heat and the second component (520) is simultaneously switched off, or vice versa, It is characterized in that The device (100) is configured to: During operation of the first component (510), a signal characterizing the temperature of a power electronic component of a switched-off second component (520) is received and evaluated in order to determine the coolant temperature of the cooling circuit (300), Furthermore, during operation of the second component (520), a signal characterizing the temperature of the power electronics of the switched-off first component (510) is received and evaluated in order to determine the coolant temperature of the cooling circuit (300).

5. A drive train (600) having a device (100) according to claims 1 to 3 or an electrical system according to claim 4, wherein: The drive train (600) comprises, in particular, a high-voltage battery (470), an inverter (472) and / or an electric machine (474).

6. A vehicle (700) having a drive train (600) according to claim 5.

7. Method (800) for ascertaining the coolant temperature of a cooling circuit (300) with a device (100) according to any one of the preceding claims, The method comprises the steps of: During operation of the first component (510), receiving (810) a signal indicative of a temperature of a power electronic device of a shut-down second power electronic device; evaluating (820) the received signal, and During operation of the second component (520), receiving (810) a signal indicative of a temperature of a power electronic device of a shut-down first power electronic device; The received signal is evaluated (820).

8. A computer program comprising commands which, when executed, cause a device according to any one of claims 1 to 6 to carry out the method (800) according to claim 7.

9. A machine-readable storage medium comprising commands which, when executed, cause the device according to any one of claims 1 to 6 to execute the method (800) according to claim 7.

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