Device and method for measuring current flow in a directly cooled conductor

Abstract

A device (1) for measuring the flow of current through at least one electrical conductor (7) of an electrotechnical device arranged in a cooling channel (6), wherein the cooling channel (6) is flowed through by a non-conductive cooling medium (8) during operation of the electrotechnical device, wherein the device (1) comprises: a flux conductor (2) arranged around the at least one electrical conductor (7); and an evaluation circuit (3) coupled to the flux conductor (2) and configured to determine the flow of current through the at least one electrical conductor (7) by evaluating an electrical parameter of the flux conductor (2), wherein at least a portion of the flux conductor (2) is arranged in the cooling channel (6). A corresponding method for measuring the flow of current is also provided.

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for determining the current flow in a directly cooled conductor, such as an electrical conductor of a liquid cooled power electronic system. Background Art

[0002] There are many different ways to measure AC and DC currents, including indirectly measuring the current by measuring the magnetic field around the current-carrying conductor. This in turn can be measured in a variety of ways, such as by current sensors that work based on Faraday's law of induction (such as current transformers or Rogowski coils, the latter of which are particularly suitable for measuring large currents), or by pure magnetic field sensors (such as Hall sensors). The current level to be measured and the installation space requirements also determine which design the inserted sensor can adopt. In general, the integration level of the sensor decreases with the intensity of the current. For measuring currents in the range of 200 amperes and above, sensors are usually used as separate components in the form of integrated circuits (ICs), while currents up to about 40 amperes are measured using fully integrated circuits.

[0003] Common to all indirect current sensors is that the magnetic field around the current-carrying conductor is "captured" and fed to an electronic evaluation circuit or used to generate a secondary current in a secondary circuit, which can then be determined directly. The ferromagnetic flux conductor and the electronics of the indirect current sensor are usually arranged in a common housing. A through-hole is provided in the housing, through which the current-carrying conductor passes, whereby an air gap exists between the two. Summary of the invention

[0004] The invention may be based on the object of providing a device by means of which the current flow in a direct cooling current conductor can be measured.

[0005] This object is achieved by a device according to a preferred embodiment of the present invention.Further examples are defined in alternative embodiments.

[0006] The device according to the present invention is a device for measuring the current flow through at least one electrical conductor of an electronic technical device. The electrical conductor is arranged in a cooling channel, which is traversed by a non-conductive cooling medium during the operation of the electronic technical device. Therefore, the electrical conductor is a directly cooled electrical conductor. In the current measuring device according to the present invention, at least a part of the flux conductor for capturing the magnetic field can be said to be arranged in the immediate vicinity of the electrical conductor in which the current flow will be determined. This also means that at least a part of the flux conductor is arranged inside the cooling channel in which the electrical conductor is also located. Therefore, at least a part of the flux conductor is arranged in a non-conductive medium, which flows through the cooling channel during the operation of the electronic technical device. In the current measuring device according to the present invention, there is a spatial separation of wet space and humid space (that is, a compartment in which a cooling fluid is present and a compartment surrounding it), and depending on the specific embodiment of the current measuring device according to the present invention, there is also a separation of components of the current sensor system, wherein at least a part of the flux conductor is arranged in the wet space. The flux conductor may include or consist of a ferromagnetic material.

[0007] The electrotechnical device may be, for example, a power electronics system installed in an electric vehicle, in particular a pulse-controlled inverter. In principle, the electrotechnical system may be any application in which current measurement is to be performed in a direct liquid-cooled current conductor.

[0008] In various embodiments of the invention, a device for measuring the flow of current through at least one electrical conductor of an electrotechnical device is provided, the electrical conductor being arranged in a cooling channel, wherein a non-conductive cooling medium flows through the cooling channel during operation of the electrotechnical device. The device according to the invention comprises a flux conductor arranged around at least one electrical conductor and an evaluation circuit, the evaluation circuit being coupled to the flux conductor and configured to determine the flow of current through at least one electrical conductor by evaluating an electrical parameter of the flux conductor, wherein at least a portion of the flux conductor is arranged in the cooling channel. The remainder of the device according to the invention for measuring the flow of current, in particular the evaluation circuit and its signal output terminal outputting a signal indicating the magnitude of the determined current, can be arranged inside or outside the cooling channel, depending on the embodiment of the device. The flux conductor surrounding at least one electrical conductor can suitably be circular, but can alternatively have other suitable shapes, such as a square with rounded corners. For example, the flux conductor can generally have a shape suitable for the electrical conductor, so that the distance between the outer surface of the electrical conductor and the inner surface of the flux conductor is constant over its perimeter.

[0009] In further embodiments, a portion of a cooling channel including at least one electrical conductor arranged therein may be part of the device according to the invention.

[0010] According to a further embodiment of the device according to the invention, the flux conductor can pass through the seal and the portion of the flux conductor located outside the cooling channel can be coupled to the evaluation circuit. In other words, the seal can serve as a dividing surface which divides the flux conductor into a portion arranged inside the cooling channel and a portion arranged outside the cooling channel. The portion of the flux conductor arranged outside the cooling channel can then be coupled to the evaluation circuit without taking any special measures with regard to tightness. The seal can be arranged at a suitable position in the wall of the cooling channel and can be opened or can be detached from the cooling channel.

[0011] According to a further embodiment of the device according to the invention, the entire flux conductor can be arranged inside the cooling channel. In this embodiment, the flux conductor is located in the wet space and is completely circumvented by the cooling medium. The interface or interface between the flux conductor and the evaluation circuit can be located inside the seal.

[0012] According to a further embodiment of the device according to the invention, the evaluation circuit can be arranged in a fluid-tight housing and mounted in an opening arranged in the cooling channel, wherein the housing also closes the opening in a fluid-tight manner. In this case, a sealing element can be arranged around the housing to support the housing, such as a thread, by which the housing is screwed into the opening in a fluid-tight manner. In any case, in this embodiment, the housing mounted in the opening of the cooling channel is sealed with said opening of the cooling channel.

[0013] According to a further embodiment of the device according to the invention, the flux conductor can be integrated in a fluid-tight housing of the electronic circuit. In this case, the device according to the invention can be configured as a module comprising a housing in which the evaluation circuit and the flux conductor are arranged, wherein the module can be mounted (e.g. screwed or pressed) into an opening provided in the wall of the cooling channel.

[0014] According to a further embodiment of the device according to the invention, the evaluation circuit can be arranged together with the flux conductor in a fluid-tight housing, which is arranged in the cooling channel. In this case, the sensor system including the flux conductor and the evaluation circuit is therefore arranged in a housing which is completely integrated in the cooling channel and is surrounded by the cooling medium.

[0015] According to a further embodiment of the device according to the invention, in which the fluid-tight housing is arranged in the cooling channel, the communication line can be led out of the fluid-tight housing to the outside and out of the cooling channel in a fluid-tight manner. The communication line is coupled to a signal output of the evaluation circuit, at which a signal indicating the magnitude of the determined current is output.

[0016] According to a further embodiment of the device according to the invention, the device may further comprise a communication module, which is configured to wirelessly communicate with a communication module arranged outside the cooling channel. For example, the wireless communication module may be part of the evaluation circuit or may be coupled to the evaluation circuit. The wireless communication module may in particular be used to transmit measurement data related to the determined current flow from the cooling channel to the outside, so that the wireless communication provided in this way may be used instead of the above-mentioned communication line through the wall of the cooling channel.

[0017] In a further embodiment of the invention, a power electronics module, in particular a power electronics module of an electric vehicle, is provided, comprising at least one directly liquid-cooled electrical conductor, wherein the power electronics module comprises a device according to the invention for measuring a current flow through the at least one electrical conductor. The power electronics module may for example be a pulse inverter.

[0018] In a further embodiment of the invention, a method for measuring a current flow through at least one electrical conductor of an electrotechnical device arranged in a cooling channel is provided, wherein a non-conductive cooling medium flows through the cooling channel during operation of the electrotechnical device. The current flow is determined by a flux conductor arranged around the at least one electrical conductor and by an evaluation circuit, the evaluation circuit being coupled to the flux conductor and configured to determine the current flow through the at least one electrical conductor by evaluating an electrical parameter of the flux conductor, wherein at least a portion of the flux conductor is arranged in the cooling channel. In a further embodiment of the method, the arrangement of the flux conductor and the evaluation circuit relative to each other and relative to the cooling channel can be selected according to any of the aforementioned embodiments of the device according to the invention for measuring a current flow through at least one electrical conductor of an electrotechnical device.

[0019] The sensor system of the device according to the invention comprising the evaluation circuit and the flux conductor can be any indirect current sensor, so that the flux conductor can correspond, for example, to a ferromagnetic (toroidal) core or a Rogowski coil.

[0020] It goes without saying that the features mentioned above and those yet to be discussed below can be used not only in the respectively specified combination but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further advantages and configurations of the invention are apparent from the entire description and drawings.

[0022] Figure 1 A schematic diagram of a first embodiment of a device for measuring the flow of electric current through at least one electrical conductor according to the invention is shown.

[0023] Figure 2A schematic diagram of a second embodiment of a device for measuring the flow of electric current through at least one electrical conductor according to the invention is shown.

[0024] Figure 3 A schematic diagram of a third embodiment of a device for measuring the flow of electric current through at least one electrical conductor according to the invention is shown. DETAILED DESCRIPTION

[0025] Figure 1-3 Schematic diagrams of different embodiments of the device 1 according to the invention are shown. The basic structure is an electrical conductor which is arranged in a cooling channel 6 and is surrounded by a cooling medium 8 or which flows around the electrical conductor during operation of the relevant electrotechnical device and on which an indirect current measurement is performed via a flux conductor 2 and an evaluation circuit 3 coupled thereto. The evaluation circuit 3 comprises a signal output 4 at which a signal indicating the magnitude of the determined current is output. Figure 1-3 Common to all the exemplary embodiments shown in FIG. 1 is that the flux conductor 2 is at least partially arranged in a cooling channel.

[0026] exist Figure 1 In the shown embodiment of the device 1 according to the invention, the flux conductor 2 is fastened in a seal 5 which seals an opening arranged in the wall of a cooling channel 6. The part of the flux conductor 2 arranged outside the cooling channel is coupled to an evaluation circuit 3.

[0027] exist Figure 2 In the illustrated embodiment of the device 1 according to the invention, the sensor system comprising the evaluation circuit 3 and the flux conductor 2 is part of a sealed arrangement and is in a closed housing ( Figure 2 The housing is mounted in an opening in the wall of the cooling channel 6 and is sealed relative to the cooling channel. Here, the sealing element 5 can be arranged on the housing or formed integrally with the housing.

[0028] at last, Figure 3 A third embodiment of the device 1 according to the invention is shown. In this embodiment, the sensor system is also arranged in a closed housing. The housing is completely integrated in the cooling channel 6 and is circulated by the cooling medium 8. The signal output 4 of the evaluation circuit is led to the outside in a fluid-tight manner via a seal arranged in the wall of the cooling channel 6.

Claims

1. A device (1) for measuring the current flow through at least one electrical conductor (7) of an electronic device arranged in a cooling channel (6), in, The cooling channel (6) is flowed through by a non-conductive cooling medium (8) during operation of the electrotechnical device, wherein the device (1) comprises: a flux conductor (2) which is arranged around the at least one electrical conductor (7); an evaluation circuit (3) which is coupled to the flux conductor (2) and is configured to determine a current flow through the at least one electrical conductor (7) by evaluating an electrical parameter of the flux conductor (2), wherein at least a portion of the flux conductor (2) is arranged in the cooling channel (6).

2. The device (1) according to claim 1, in, The flux conductor (2) is guided through a seal (5), and the section of the flux conductor (2) which is located outside the cooling channel (6) is coupled to the evaluation circuit (3).

3. The device (1) according to claim 1, in, The entire flux conductor (2) is arranged inside the cooling channel (6).

4. The device (1) according to claim 3, in, The evaluation circuit (3) is arranged in a fluid-tight housing and is mounted in an opening provided in the cooling channel (6), wherein the housing simultaneously also closes the opening in a fluid-tight manner.

5. The device (1) according to claim 4, in, The flux conductor (2) is integrated into a fluid-tight housing of the evaluation circuit (3).

6. The device (1) according to claim 3, in, The evaluation circuit (3) is arranged together with the flux conductor (2) in a fluid-tight housing which is arranged in the cooling channel (6).

7. The device (1) according to claim 6, in, The communication line is led outward from the fluid-tight housing and is led out of the cooling channel (6) in a fluid-tight manner.

8. The device (1) according to claim 6, further comprising: include: A communication module is configured to wirelessly communicate with a communication module arranged outside the cooling channel (6).

9. A power electronics module having at least one directly liquid-cooled electrical conductor (7), wherein the power electronics module comprises a device (1) for measuring a current flow through the at least one electrical conductor (7) according to any of the preceding claims 1 to 8.

10. The power electronic module according to claim 9, in, The power electronic module is a power electronic module of an electric vehicle.

11. A method for measuring the current flow through at least one electrical conductor (7) of an electronic device arranged in a cooling channel (6), in, A non-conductive cooling medium (8) flows through the cooling channel (6) during operation of the electronic technical device (1), wherein the current flow is determined by a flux conductor (2) arranged around the at least one electrical conductor (7) and an evaluation circuit (3), which is coupled to the flux conductor (2) and is configured to determine the current flow through the at least one electrical conductor (7) by evaluating an electrical parameter of the flux conductor (2); wherein at least a portion of the flux conductor (2) is arranged in the cooling channel (6).

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