EP-4735900-A1 - SHUNT WITH CONDUCTOR AND COOLING DEVICE

EP4735900A1EP 4735900 A1EP4735900 A1EP 4735900A1EP-4735900-A1

Abstract

The invention relates to a shunt for measuring an electric current. The shunt has a conductor (1) with at least one input contact (3a) and at least one output contact (3b), wherein the conductor (1) has at least one measuring section (6), and at least one cooling device (5) is arranged on the conductor (1) in order to cool the conductor (1). The invention is characterized in that the conductor (1) extends along a longitudinal axis (A) along which a current substantially flows, the conductor (1) has two longitudinal segments (2a, 2b) which likewise extend along the longitudinal axis (A) and which are arranged at the same height along the longitudinal axis (A), each of the longitudinal segments (2a, 2b) has a contact point for introducing or discharging the current to be measured at a first end (4a) along the longitudinal axis (A), and the longitudinal segments (2a, 2b) are electrically connected together at a second end (4b) along the longitudinal axis (A).

Inventors

KARANOVIC, Stefan
KLUG, ANDREAS
NEUWIRTH, WERNER
REISINGER, ERWIN

Assignees

AVL List GmbH

Dates

Publication Date: 20260506
Application Date: 20240628

Claims (13)

1. Shunt for measuring electrical current, wherein the shunt has a current conductor (1) for conducting the current to be measured with at least one input contact (3a) and at least one output contact (3b), wherein the current conductor (1) has at least one measuring section (6), and wherein at least one cooling device (5) for cooling the current conductor (1) is arranged on the current conductor (1), characterized in that the current conductor (1) extends along a longitudinal axis (A) along which current is essentially guided, that the current conductor (1) has two length segments (2a, 2b) which also extend along the longitudinal axis (A) and are arranged at the same height along the longitudinal axis (A), that at a first end (4a) along the longitudinal axis (A) the length segments (2a, 2b) each have the input contact (3a) or the output contact (3b) and that the length segments (2a, 2b) at a second end (4b) along the longitudinal axis (A) are electrically connected to each other.
2. Shunt according to claim 1, characterized in that the length segments (2a, 2b) have substantially the same longitudinal extension (10a, 10b) along the longitudinal axis (A).
3. Shunt according to claim 1 or 2, characterized in that the length segments (2a, 2b) lie along their longitudinal extent (10a, 10b) along the longitudinal axis (A) and are preferably separated from one another exclusively by an electrical insulator (7).
4. Shunt according to one of claims 1 to 3, characterized in that the measuring section (6) is designed as part of at least one of the length segments (2a, 2b).
5. Shunt according to one of claims 1 to 4, characterized in that the length segments (2a, 2b) are at least partially designed as tubes (5a) which are arranged substantially coaxially and that preferably the measuring section (6) is arranged on the outer length segment (2a, 2b).
6. Shunt according to one of claims 1 to 5, characterized in that the cooling device (5) is electrically insulated from the length segment (2a, 2b) on which it is arranged.
7. Shunt according to one of claims 1 to 6, characterized in that the measuring section (6) has a greater resistance than the remaining current conductor (1).
8. Shunt according to one of claims 1 to 7, characterized in that the cooling device (5) comprises a cooling channel (5c) which extends along at least one of the length segments (2a, 2b) and that preferably the cooling channel (5c) is electrically insulated from the coolant.
9. Shunt according to claim 8 in combination with claim 5, characterized in that the cooling channel (5c) is guided in one of the two tubes (5a).
10. Shunt according to one of claims 1 to 9, characterized in that at least one measuring point (6a, 6b) is arranged at each end of the measuring section.
11. Shunt according to one of claims 1 to 10, characterized in that the cooling device (5) is an active cooling device.
12. Current measuring device with a shunt for the current to be determined to flow through, wherein the shunt is designed according to one of the preceding claims, and wherein the current measuring device has a voltmeter (14) for measuring the voltage drop along the measuring section (6), which is electrically connected to measuring points (6a, 6b) of the shunt and the current measuring device has an evaluation unit (13) for calculating the current flowing through the shunt (1), and that the evaluation unit (13) is connected to the voltmeter (14).
13. A method for measuring an electric current with a shunt, comprising the following steps: Providing at least one shunt according to one of claims 1 to 11 or a current measuring device according to claim 12; Conducting the current to be determined through a first length segment (2a) of the current conductor (1) of the shunt along a longitudinal axis (A) and through a second length segment (2b) of the current conductor (1) of the shunt along the longitudinal axis (A) in the opposite direction and at the same height along the longitudinal axis (A) as the first longitudinal segment (2a); Calculation of the current to be determined taking into account the voltage drop along the measuring section (3) and the resistance of the measuring section (2). 2024 06 28 MT

Description

Shunt with current conductor and cooling device The invention relates to a shunt for measuring electrical current, wherein the shunt has a current conductor for conducting the current to be measured with at least one input contact and at least one output contact, wherein the current conductor has at least one measuring section and wherein at least one cooling device for cooling the current conductor is arranged on the current conductor. It also relates to a method for measuring an electric current with a shunt and to a current measuring device with a shunt. A shunt, also called a shunt resistor or current measuring resistor, is an electrical component that is used to measure electrical currents, especially larger currents, such as those in the range of over 100 amps. To do this, the current to be measured is passed through the shunt. A measuring section of the shunt has a defined resistance and by measuring the voltage drop along this measuring section, the current strength can be determined. Such shunts suffer from the thermal stress caused by the high current, which on the one hand means physical strain and on the other hand also worsens the measurement result, since the temperature also changes the resistance of the measuring section. Therefore, many shunts can often only be used for short periods of time, for example less than two minutes. In addition, due to the high current, shunts generate strong electromagnetic fields that can interfere with other components. US 6498499 Bl discloses a measuring device for measuring the capacitance of electrical wires. A water bath cooling device is disclosed on two measuring sections arranged one behind the other. The measuring sections are located at different heights of the channel. However, the current is not measured. Such an arrangement is also not suitable for measuring high currents and has the problems mentioned above. The object of the invention is to provide a shunt, a current measuring device and an above-mentioned method which has a longer operating time with the lowest possible electromagnetic interference in its environment. This object is achieved according to the invention in that the current conductor extends along a longitudinal axis along which current is essentially guided, in that the current conductor has two length segments which also extend along the longitudinal axis and are arranged at the same height along the longitudinal axis, that at a first end along the longitudinal axis the length segments each have the input contact or the output contact and that the length segments are electrically connected to one another at a second end along the longitudinal axis. It is also solved by the fact that the procedure comprises the following steps: Providing at least one shunt according to the invention or one current measuring device according to the invention; Conducting the current to be determined through a first length segment of the current conductor of the shunt along a longitudinal axis and through a second length segment of the current conductor of the shunt along the longitudinal axis in the opposite direction and at the same height along the longitudinal axis as the first length segment; Calculation of the current to be determined taking into account the voltage drop along the measuring section as well as the resistance of the measuring section. The process steps can sometimes be carried out simultaneously or in a different order. Steps can also be carried out in between, before or after. The electrical resistance of the measuring section is usually known very precisely. Using Ohm's law, the current flowing can be determined by measuring the voltage drop along the measuring section. The current to be determined can be calculated using the formula I = U / R, where I is the current to be determined, U is the measured voltage drop and R is the electrical resistance of the measuring section. By arranging the length segments at the same height, the electromagnetic radiation generated by the two length segments cancels each other out, at least in part. This results in a significant reduction in electromagnetic radiation and thus less disturbance to the environment. In addition, the arrangement of the cooling device results in a significantly lower thermal load. Both of these effects mean that the shunt can be operated for longer or even continuously, even at high currents. The measuring section extends along at least part of the current conductor, preferably along part of the current conductor, but it can also cover the entire current conductor. The current conductor is a part of the shunt along which the current to be measured is conducted. It is usually limited along the current flow by the input contact and the output contact and has the measuring section. The measuring section can also extend over the entire length of the current conductor. In this document, resistance refers to electrical resistance, unless explicitly stated otherwise. The