DE202021105281U1 - Current sense resistor - Google Patents

Abstract

Current measuring resistor (1) for measuring an electrical current (I), with
a) a first connection part (2) made of an electrically conductive material, in particular for introducing the electrical current (I) to be measured into the current measuring resistor (1),
b) a second connection part (3) made of an electrically conductive conductor material, in particular for discharging the electrical current (I) to be measured from the current measuring resistor (1),
c) a resistance element (6) made of a resistance material, the resistance element (6) being arranged in the main current flow direction between the first connection part (2) and the second connection part (3), so that the current (I) to be measured flows through the resistance element (6 ) flows,
d) a first voltage measuring contact (9) on the first connection part (2) for voltage measurement on the first connection part (2),
e) a second voltage measuring contact (11) on the second connection part (3) for measuring the voltage on the second connection part (3), and
f) a first incision (13) in the second connection part (3), the first incision (13) surrounding the second voltage measuring contact (11) and preventing a current flow across the first incision (13), characterized in that,
g) that a third voltage measuring contact (12) is arranged on the second connection part (3) in order to measure the voltage on the second connection part (3), and
h) that the third voltage measuring contact (12) on the second connection part (3) is arranged offset with respect to the main current flow direction transversely to the second voltage measuring contact (11) on the second connection part (3).

Description

Technical field of the invention

The invention relates to a current measuring resistor for measuring an electrical current using four-wire technology.

Background of the invention

the end EP 0 605 800 A1 it is known to measure an electrical current by means of a low-ohmic current measuring resistor (“shunt”) using four-wire technology. The electrical current to be measured is passed through the low-ohmic current measuring resistor, the voltage drop across the low-ohmic current measuring resistor being measured. The measured voltage drop across the low-ohmic current measuring resistor is then, according to Ohm's law, a measure of the electrical current flowing through the low-ohmic current measuring resistor.

It is still off WO 2012/019784 A1 a further developed low-ohmic current measuring resistor is known in which the voltage measuring contacts of the low-ohmic current measuring resistor are surrounded by incisions, which are also referred to as current shadows and prevent a current flow across the respective incision. These cuts have a positive effect on the electrical field distribution in the low-ohmic current measuring resistor.

The disadvantage of this known current measuring resistor according to the prior art is the fact that measurement errors cannot be easily recognized.

Description of the invention

The invention is therefore based on the object of creating a correspondingly improved low-resistance current measuring resistor.

This object is achieved by a current measuring resistor according to the invention in accordance with the main claim.

The invention encompasses the general technical teaching of providing a three-point tap for voltage measurement on a low-ohmic current measuring resistor, the three-point tap enabling three voltage measurements on a closed mesh that extends over the resistance element. The three-point tap therefore provides three measurement channels that deliver three voltage measurement values. In the case of an error-free measurement, the sum of all stresses in the closed mesh must be zero in accordance with Kirchhoff's second law. In the event of a measurement error, however, a deviation from zero occurs, which enables error detection.

The current measuring resistor according to the invention initially has, in accordance with the known current measuring resistor described above, a first connection part which consists of an electrically conductive material (e.g. copper) and preferably serves to introduce the electric current to be measured into the current measuring resistor.

In addition, the current measuring resistor according to the invention, in accordance with the known current measuring resistor described at the beginning, has a second connection part, which also consists of an electrically conductive material (e.g. copper) and preferably serves to dissipate the electrical current to be measured from the current measuring resistor.

Furthermore, the current measuring resistor according to the invention also has a resistance element made of a resistance material (e.g. Manganin®), the resistance element being arranged in the main current flow direction between the first connection part and the second connection part, so that the electrical current to be measured flows through the resistance element.

In addition, the current measuring resistor according to the invention for voltage measurement also has a first voltage measuring contact on the first connection part and a second voltage measuring contact on the second connection part.

The second voltage measuring contact is surrounded by an incision, which is also referred to as a current shadow and prevents a current flow across the incision. In contrast to the known current measuring resistor according to WO 2012/019784 A1 In the current measuring resistor according to the invention, an incision (current shadow) is preferably only provided in one of the two connection parts, while the other connection part does not contain such an incision.

The current measuring resistor according to the invention is now characterized in that a third voltage measuring contact is additionally arranged on the second connection part in order to measure the voltage on the second connection part. The third voltage measuring contact on the second connection part is arranged offset with respect to the main current flow direction transversely to the second voltage measuring contact on the second connection part. The three voltage measuring contacts thus enable the three-point pick-up already mentioned above and form a closed mesh for voltage measurement, which is what was mentioned above Diagnostic function enables. With four voltage measuring contacts, two such meshes can then be formed, each comprising three voltage measuring contacts, the sum of the voltages on one mesh circuit then having to be zero.

In a preferred exemplary embodiment of the invention, the first voltage measuring contact on the first connection part and the second voltage measuring contact on the second connection part jointly form a first measuring channel for voltage measurement, with a first measured voltage value ( U12 ) is output. The first voltage measurement on the first measuring channel is preferably carried out parallel to the main current flow direction in the current measuring resistor. In addition, it is provided in this exemplary embodiment that the first voltage measuring contact on the first connection part, together with the third voltage measuring contact on the second connection part, forms a second measuring channel in order to avoid a second voltage drop ( U13 ) above the resistance element and at an angle to the main current flow direction. In addition, the second voltage measuring contact on the second connection part, preferably together with the third voltage measuring contact on the second connection part, forms a third measuring channel in order to avoid a third voltage drop ( U23 ) to measure transversely to the main current flow direction, in particular at right angles to the main current flow direction. The three measurement channels provide three voltage measurement values ( U12 , U13 , U23 ), which result in a total of zero in the case of an error-free measurement, taking into account the sign. If there is a deviation from zero, however, there is a measurement error.

In another exemplary embodiment of the invention, on the other hand, the second voltage measuring contact on the second connection part, together with the third voltage measuring contact on the second connection part, forms a first measuring channel in order to avoid a first voltage drop ( U23 ) to measure transversely to the main current flow direction, in particular at right angles to the main current flow direction. In this exemplary embodiment, the first voltage measuring contact on the first connection part forms, preferably together with the third voltage measuring contact, a second connection part, a second measuring channel in order to avoid a second voltage drop ( U13 ) to measure across the resistance element at an angle to the main current flow direction. In addition, the first voltage measuring contact on the first connection part together with the second voltage measuring contact on the second connection part preferably forms a third measuring channel in order to avoid a third voltage drop ( U12 ) to measure across the resistance element and preferably parallel to the main current flow direction. A three-point tap with the diagnostic function described above is also made possible in this exemplary embodiment.

Furthermore, within the scope of the invention there is the possibility that a fourth voltage measuring contact is arranged on the second connection part, which is electrically conductively connected to the third voltage measuring contact in order to measure the voltage jointly at the third voltage measuring contact and at the fourth voltage measuring contact. The third voltage measuring contact and the fourth voltage measuring contact thus offer a common voltage tap.

In addition, a fifth voltage measuring contact can be arranged on the first connection part, which is electrically conductively connected to the first voltage measuring contact in order to measure the voltage jointly at the first voltage measuring contact and at the fifth voltage measuring contact. The first voltage measuring contact and the fifth voltage measuring contact thus form a common voltage tap.

It should also be mentioned that the first voltage measuring contact on the first connection part is preferably arranged centrally with respect to the side edges of the current measuring resistor, in particular with an eccentricity that is less than 50%, 40%, 30%, 20%, 10% or even 5% the width of the current measuring resistor.

The same preferably also applies to the second voltage measuring contact and the incision surrounding it in the second connection part, which are also preferably arranged centrally with respect to the side edges of the current measuring resistor, in particular with an eccentricity that is less than 50%, 40%, 30%, 20 %, 10% or 5% of the width of the current sense resistor.

The third voltage measuring contact on the second connection part, on the other hand, is preferably arranged eccentrically so that the three-point tap forms a triangular mesh over the resistance element.

It should also be mentioned that the first voltage measuring contact is on the first connection part and the second voltage measuring contact is on the second connection part preferably have essentially the same distance from the side edges of the current measuring resistor, so that the first voltage drop across the resistance element is measured parallel to the main current flow direction in the current measuring resistor.

It should also be mentioned that in the second connection part the third voltage measuring contact and the optional fourth voltage measuring contact can preferably have essentially the same distance from the central axis of the current measuring resistor.

It should also be mentioned that in the second connection part the second voltage measuring contact is preferably arranged between the third and - if present - the fourth voltage measuring contact.

The above-mentioned incision (current shadow) in the second connection part is preferably arcuate, in particular V-shaped or U-shaped. The base of the arcuate incision is preferably oriented transversely to the main current flow direction in the current measuring resistor, while the legs of the arcuate incision are preferably oriented essentially parallel to the main current flow direction and face the resistance element.

With regard to the length of the legs of the incision, there are various possibilities within the scope of the invention, which are briefly described below.

In a variant of the invention, the legs of the incision protrude into the resistance element in the main current flow direction and end in the resistance element. Here again there is the possibility that the two legs protrude equally far into the resistance element or differently. The leg length within the resistance element can for example be in the range of 0.1 mm - 3 mm, 0.2 mm - 2 mm, 0.5 mm - 1.5 mm or approximately 1 mm.

In another variant of the invention, however, the legs of the incision end in the main current flow direction in front of the resistance element, i.e. the legs of the incision do not protrude into the resistance element. Here, the legs can have a distance from the resistance element, which can be, for example, in the range of 0.1 mm - 3 mm, 0.2 mm - 2 mm, 0.5 mm - 1.5 mm or 1 mm.

In a third variant of the invention, on the other hand, the legs of the incision extend exactly as far as the boundary between the resistance element and the second connection part.

It should also be mentioned that the second voltage measuring contact and the surrounding incision can alternatively also be arranged eccentrically in the second connection part. This means that the second voltage measuring contact and the surrounding incision are at a smaller distance from one side edge of the current measuring resistor than from the opposite side edge. In this case, the incision preferably starts from the closer side edge of the current measuring resistor and extends in an arc-shaped or L-shaped manner into the resistance element or at least as far as the boundary between the second connection part and the resistance element.

In general, it should be mentioned that the invention is not limited to a specific conductor material of the connection parts. For example, the conductor material can be copper, a copper alloy, aluminum or an aluminum alloy.

It should be mentioned, however, that the conductor material of the connection parts typically has a lower specific electrical resistance than the resistance material of the resistance element.

With regard to the resistance material of the resistance element, the invention is not restricted to a specific resistance material either. For example, a copper alloy such as a copper-manganese alloy can be used. Examples are CuMn12Ni2 or CuMn7Sn2,3. Furthermore, a copper-manganese-nickel alloy such as Cu84Ni4Mn12 or Cu65Mn25Ni10 can also be used. In addition, a copper-chromium alloy or a nickel alloy can alternatively be used.

In the preferred exemplary embodiment of the invention, the resistance element is electrically and mechanically connected to the two adjoining connection parts, for example by a welded connection, an electron welded connection having proven to be particularly advantageous.

The resistance material of the resistance element preferably has a relatively small specific electrical resistance, which is preferably less than 2 · 10 ^-4 Ω · m, 2 · 10 ^-5 Ω · m or 2 · 10 ^-5 Ω · m. The specific electrical resistance of the resistance material, on the other hand, is preferably greater than 2 · 10 ^-5 Ω · m, 2 · 10 ^-7 Ω · m.

The conductor material of the connection parts, on the other hand, preferably has an even lower specific electrical resistance, which is preferably less than 10 ^-6 Ω · m or 10 ^-7 Ω · m.

It has already been mentioned above that the current measuring resistor is low in the preferred exemplary embodiment. For example, the resistance value can be at most 1 µΩ, 10 µΩ, 20 µΩ, 33 µΩ, 50 µΩ, 100 µΩ, 500 µΩ, 10 mΩ, 5 mΩ, 2 mΩ or 1 mΩ.

It should also be mentioned that the current measuring resistor according to the invention can have a current carrying capacity which allows at least 1 A, 10 A, 100 A, 1 kA or even 5 kA with a continuous load.

With regard to the structural design of the current measuring resistor, it should be mentioned that the resistance element and the connection parts are preferably each designed in the form of a plate, the plate-shaped parts optionally being able to be flat or curved.

The length of the current measuring resistor in the main flow direction is preferably less than 30 cm, 20 cm, 10 cm, 5 cm, 2 cm or 1 cm, while the width is preferably less than 20 cm, 10 cm, 5 cm, 2 cm or 1 cm. In contrast, the thickness of the current measuring resistor is preferably less than 10 mm, 5 mm, 4 mm, 2 mm or 1 mm.

In addition, it should be mentioned that the two connection parts can each have a power connection in order to feed or discharge the electric current into the current measuring resistor, wherein these power connections can consist, for example, of a bore that can accommodate a screw, as per se EP 0 605 800 A1 is known.

The individual voltage measuring contacts can each be designed as contact islands which consist of an electrically conductive coating on the respective connection part. These contact islands can, for example, be essentially rectangular, with the coating material of the contact islands being able to consist of a different conductor material than the connecting parts lying thereunder.

It should also be mentioned that trimming cuts can be made on one or both sides of the resistance element in order to set the resistance value of the current measuring resistor and / or the temperature coefficient of the resistance value of the current measuring resistor.

In the preferred exemplary embodiment of the invention, the current measuring resistor has voltage measuring contacts for precisely three voltage measuring channels in order to enable the three-point tap mentioned at the outset. The three-point tap enables a voltage measurement along a closed mesh over the resistance element, which enables a diagnostic function.

The current measuring resistor according to the invention was described above as a single component. However, the invention also claims protection for a current measuring device with such a current measuring resistor and a voltage measuring device for separate voltage measurement on the individual measuring channels of the current measuring resistor.

In addition, the current measuring device can also have an evaluation unit in order to determine the current flowing through the current measuring resistor from the various voltage measured values. The evaluation unit can also perform a diagnostic function here. For this purpose, the voltage measuring device can measure the voltages on the three measuring channels of the three-point tap and then calculate the voltage deviation that occurs during a rotation measurement along the closed mesh. The evaluation unit can then generate an error signal if the deviation exceeds a permissible maximum value.

Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred exemplary embodiments of the invention with reference to the figures.

Figure list

• 1A shows a perspective view of a current measuring resistor according to the invention with a three-point tap.
• 1B shows a plan view of the current measuring resistor according to FIG 1A .
• 2A shows a plan view of a current measuring resistor according to the invention similar to the current measuring resistor according to FIG 1A and 1B .
• 2 B shows a modification of the current measuring resistor 2A , the legs of the incision terminating at the boundary with the resistance element.
• 2C shows a modification of the current measuring resistor according to FIG 2A , wherein the legs of the incision do not extend into the resistance element.
• 3 shows the course of the resistance value as a function of the incision length of the legs within the resistance element.
• 4th FIG. 11 shows an enlarged detailed view of the current measuring resistor from FIG 1A and 1B in the area of the incision.
• 5 shows the change in resistance as a function of temperature for different lengths of the incision inside and outside the resistance element.
• 6th shows the change in resistance as a function of temperature also for different incision lengths inside and outside the resistance element.
• 7th shows a current measuring device according to the invention with the current measuring resistor according to the invention.
• 8th shows a plan view of a modified embodiment of a current measuring resistor according to the invention.
• 9 shows a perspective view of a modified embodiment of a current measuring resistor according to the invention.
• 10 shows a flow chart to illustrate a diagnostic method.
• 11A shows a modification of the embodiment according to 9 with two additional incisions to influence the temperature behavior.
• 11B FIG. 11 shows a diagram to illustrate the temperature behavior in the exemplary embodiment according to FIG 11A .
• 12-17 show various modifications of the embodiment according to FIG 11A .

Detailed description of the drawings

The exemplary embodiment of a current measuring resistor according to the invention will now be described below 1 described in the 1A and 1B is shown. This is how the current measuring resistor is used 1 for current measurement according to the four-wire technique, which is known per se from the prior art.

First of all, the current measuring resistor 1 a first plate-shaped connection part 2 made of copper, which is used to generate an electric current I. into the current measuring resistor 1 initiate.

In addition, the current measuring resistor 1 a plate-shaped connector 3 on, which is also made of copper and is used to generate electricity I. again from the current measuring resistor 1 to divert.

In the two connecting parts 2 , 3 there is one hole in each case 4th respectively. 5 to carry out a screw for power contact, as it was already out EP 0 605 800 A1 is known.

Between the two connecting parts 2 , 3 there is a resistance element 6th made of a resistance material (e.g. Manganin®), the resistance element 6th at its edges by electron beam welding to the two connecting parts 2 respectively. 3 connected is.

In the resistance element 6th there are trimming cuts on the side 7th , 8th for setting the resistance value and the temperature coefficient of the current measuring resistor 1 as is known per se from the prior art.

At the top of the current sense resistor 1 are located on the two connection parts 2 , 3 four voltage measuring contacts 9, 10 , 11th , 12th to measure the over the resistance element 6th decreasing electrical voltage and also to enable a diagnostic function, as will be described in detail below.

The voltage measuring contact 11th in the second connector 3 is arranged in the middle and by an incision 13th which is also known as the current shadow and a current flow at right angles across the incision 13th prevented. The incision 13th is here U-shaped with a base 14th perpendicular to the main current flow direction in the current measuring resistor 1 and two legs 15th , 16 that are parallel to the main current flow direction in the current measuring resistor 1 are aligned and the resistance element 6th facing, with the legs 15th , 16 of the incision 13th in this embodiment up to the resistance element 6th protrude (cf. 4th ).

The voltage measuring contact 9 forms here together with the voltage measuring contact 11th a first measuring channel 17 on which a corresponding voltage measurement U12 is issued.

Furthermore, the voltage measuring contact 9 forms with the voltage measuring contact 12th a second measuring channel 18, on which a further voltage measurement U13 is issued.

Finally, the voltage measuring contact forms 11th together with the voltage measuring contact 12th a third measuring channel 19, on which a further voltage measurement value U23 is issued.

The voltage measuring contacts 9, 11th and 12th form a closed mesh over the resistance element 6th so that the sum of all stresses in the mesh must be zero according to Kirchhoff's Second Law. The voltage taps 9, 11th , 12th thus form a three-point tap, which enables a diagnostic function, as will be described in detail later.

The optional voltage measuring contact 10 is conductive to the voltage measuring contact 12th connected so that the voltage measuring contacts 10 , 12th form a common voltage tap.

The embodiment according to 2A largely corresponds to the embodiment described above, so that to avoid repetitions on the reference is made to the above description, the same reference numerals being used for corresponding details. In this embodiment, too, the two legs protrude 15th , 16 of the U-shaped incision 13th down to the resistance element 6th into it.

With the variant according to 2 B protrude the thighs 15th , 16 of the U-shaped incision 13th on the other hand not up to the resistance element 6th into it, but end at the boundary between the resistance element 6th and the connector 3 .

With the variant according to 2C end the thighs 15th , 16 of the U-shaped incision 13th on the other hand, even within the connector 3 and thus do not extend to the boundary between the resistance element 6th and the connector 3 .

4th FIG. 13 shows an enlargement in the embodiment according to FIG 1B in the area of the U-shaped incision 13th . It can be seen here that the legs 15th , 16 of the U-shaped incision 13th with a length dx down to the resistance element 6th protrude.

3 shows the dependence of the resistance value on the length of the cut dx for the partial resistances R12 , R13 , R23 of the three-point tap ( U12 , U13 , U23 ).

Furthermore shows 5 the relative change dR12 of the resistance value R12 as a function of the temperature for different values of dx.

Another such diagram for R23 is also in 6th shown.

7th now shows the current measuring resistor according to the invention 1 no longer as a single component, but as part of a current measuring device.

The voltage measuring channels 17, 18 and 19 are hereby a voltage measuring device 20th read out which the three voltage readings U12 , U13 and U23 recorded. The tension measuring device 20th gives the voltage readings U12 , U13 , U23 then to an evaluation unit 21 further that has two functions.

On the one hand, the evaluation unit calculates 21 from the voltage measured values U12 , U13 , U23 the current according to Ohm's law I. , which is determined by the current measuring resistor 1 flows.

On the other hand, the evaluation unit fulfills 21 but also a diagnostic function to detect measurement errors, the diagnostic function below with reference to the flowchart in 10 is described. It was already mentioned above that the voltage measurement values U12 , U13 , U23 reproduce the stresses in a closed mesh and therefore have to be zero in total according to Kirchhoff's Second Law.

The diagnostic method therefore provides in a step S1 that the current to be measured is passed through the current measuring resistor 1 is passed through.

The voltage drops are then set in steps S2-S4 U12 , U13 , U23 measured.

In the next step S5, a deviation ΔU = U12 + U23-U13 is then calculated.

In the next step S6, it is then checked whether the deviation .DELTA.U exceeds _{a predetermined maximum value .DELTA.U MAX.}

If this is the case, it is assumed in a step S8 that the current measurement was incorrect.

Otherwise, however, it is assumed in a step S7 that the current measurement was correct.

8th shows a modification of the exemplary embodiments described above, so that reference is made to the above description to avoid repetition, the same reference symbols being used for corresponding details.

A special feature of this embodiment is that in the connection part 2 in addition to the voltage measuring contact 9 further voltage measuring contacts 22nd , 23 are arranged, but form a common voltage tap with the voltage measuring contact 9.

The embodiment according to 9 again partially corresponds to the exemplary embodiments described above, so that in order to avoid repetition reference is made to the preceding description, the same reference symbols being used for corresponding details.

A special feature of this embodiment is that the incision 13th is not U-shaped, but L-shaped. The L-shaped incision 13th goes here from a side edge of the current measuring resistor 1 and then protruded with the other leg into the resistance element 6th into it.

The embodiment according to 11A largely agrees with the embodiment according to 9 so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this embodiment is that in the connection part 3 Another incision on the side 24 is arranged to allow a current to flow across the incision 24 prevented.

The incision 24 goes here from the side edge of the connector 3 and runs transversely to the main current flow direction in the current measuring resistor 1 .

Between the incision 24 and the resistance element 6th the voltage measuring contact is located here 12th on a contact pad by the incision 24 is separated.

In addition, it is also in the connector 2 an incision 25th arranged to allow a current to flow across the incision 25th prevented.

The incision 25th goes here from the opposite side edge of the connection part 2 and extends transversely to the main current flow direction in the current measuring resistor 1 . The two incisions 24 , 25th are therefore on opposite sides of the current measuring resistor 1 arranged with the two incisions 24 , 25th here have a different length, ie the incision 25th is longer than the incision 24 .

Between the incision 25th and the resistance element 6th Here, the voltage measuring contact 9 is on a contact island that is from the incision 25th is separated.

The cuts 24 , 25th improve the temperature behavior of the current measuring resistor 1 as according to the diagram 11B can be seen. The various characteristics in 11B the relative change in various voltage readings U12 , U23 and U13 depending on the temperature. The voltage U12 is between the two voltage measuring contacts 9, 11th measured while the voltage U23 between the two voltage measuring contacts 11th , 12th is measured. Eventually the tension becomes U13 between the voltage measuring contacts 9, 12th measured. In the diagram, the round measuring points show the temperature dependency without the cuts 24 , 25th , while the triangular measuring points show the corresponding course for the exemplary embodiment according to FIG 11A with the incisions 24 , 25th shows. The comparison of the different characteristics clearly shows that the temperature dependency of the voltage measurement values is due to the two incisions 24 , 25th is significantly reduced.

The embodiment according to 12th largely agrees with that described above and in 11A illustrated embodiment, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this embodiment is that the incision 13th is not L-shaped, but an arc of a circle.

13th shows a further modification of the embodiment according to FIG 11A so that, to avoid repetition, reference is made to the above description, the same reference symbols being used for corresponding details.

A special feature of this embodiment is that the incision 13th here is neither L-shaped nor arc-shaped, but runs straight and at an angle to the side edge of the current measuring resistor 1 is aligned.

14th shows a further modified embodiment, which largely corresponds to that described above and in 11A The illustrated embodiment corresponds, so that reference can again be made to the above description in order to avoid repetition.

A special feature of this embodiment is that the two incisions 24 , 25th here are circular arc-shaped. The two incisions 24 , 25th go here from opposite side edges of the current measuring resistor 1 and then run in an arc in the direction of the resistance element 6th , making the incisions 24 , 25th not up to the resistance element 6th extend.

15th shows a further modification of the embodiment according to FIG 11A so, to avoid repetition, refer to the description above 11A is referred to, the same reference numerals being used for corresponding details.

A special feature of this embodiment is that the two incisions 24 , 25th here are L-shaped. The two incisions 24 , 25th go here from opposite side edges of the current measuring resistor 1 off and are then in the direction of the resistance element 6th angled, with the incisions 24 , 25th not up to the resistance element 6th reach.

16 shows another variation of 11A so that, to avoid repetition, reference is made to the above description, the same reference symbols being used for corresponding details.

A special feature of this embodiment is that in the connection part 2 an additional voltage measuring contact 26th is provided, the voltage measuring contact 26th on one side edge of the connector 2 adjacent to the resistance element 6th is located.

In addition, the connection part 2 another incision 27 from the side edge of the connector 2 goes out and then L-shaped into the resistance element 6th extends into it, the incision 27 in the connector 2 a contact island for the voltage measuring contact 26th separates.

In this exemplary embodiment, the current measuring resistor 1 so four voltage measuring contacts 9, 11th , 12th , 26th on, which enables a variety of voltage measurements.

The embodiment according to 17th largely agrees with that described above and in 16 illustrated embodiment, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this embodiment is that the incision 27 in the embodiment according to 17th further into the resistance element 6th extends into it than in the embodiment according to FIG 16 The invention is not restricted to the preferred exemplary embodiments described above. Rather, a large number of variants and modifications are possible which also make use of the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and the features of the subclaims independently of the claims referred to in each case and in particular also without the features of the main claim. The invention thus comprises various aspects of the invention that are protected independently of one another.

List of reference symbols

1

Current sense resistor

2

Connection part for introducing the current into the current measuring resistor

3

Connection part for discharging the current from the current measuring resistor

4th

Hole in the connection part for introducing the current

5

Hole in the connection parts for discharging the current

6th

Resistance element between the connection parts

7, 8

Trim cuts in the resistance element

9-12

Voltage measuring contacts

13th

U-shaped incision in the connection part

14th

Base of the U-shaped incision

15, 16

Leg of the U-shaped incision

17-19

Measuring channels of the voltage measuring device

20th

Voltage measuring device

21

Evaluation unit

22, 23

Voltage measuring contacts

24

Incision in the connector

25th

Incision in the connector

26th

Voltage measuring contact

27

Incision in the connector

I.

Current through the current measuring resistor

dx

Length of the legs of the U-shaped incision within the resistance element

U12

Voltage reading

U13

Voltage reading

U23

Voltage reading

R12

Resistance reading

R13

Resistance reading

R23

Resistance reading

dR12

Relative change in resistance reading

dR13

Relative change in resistance reading

dR23

Relative change in resistance reading

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 0605800 A1 [0002, 0040, 0050]
• WO 2012/019784 A1 [0003, 0012]

Claims (19)

Current measuring resistor (1) for measuring an electrical current (I), with a) a first connection part (2) made of an electrically conductive material, in particular for introducing the electric current (I) to be measured into the current measuring resistor (1), b) a second Connection part (3) made of an electrically conductive material, in particular for discharging the electrical current (I) to be measured from the current measuring resistor (1), c) a resistance element (6) made of a resistance material, the resistance element (6) in the main current flow direction between the first Connection part (2) and the second connection part (3) is arranged so that the current to be measured (I) flows through the resistance element (6), d) a first voltage measuring contact (9) on the first connection part (2) for voltage measurement on the first connection part (2), e) a second voltage measuring contact (11) on the second connection part (3) for voltage measurement on the second connection part (3), and f) a first n incision (13) in the second connection part (3), wherein the first incision (13) surrounds the second voltage measuring contact (11) and prevents a current flow across the first incision (13), characterized in that g) that on the second connection part (3) a third voltage measuring contact (12) is arranged to measure the voltage at the second connection part (3), and h) that the third voltage measuring contact (12) is arranged on the second connection part (3) with respect to the main current flow direction transversely to the second voltage measuring contact (11) is arranged offset on the second connection part (3). Current measuring resistor (1) Claim 1 , characterized in , a) that the first voltage measuring contact (9) on the first connection part (2) together with the second voltage measuring contact (11) on the second connection part (3) forms a first measuring channel (17) in order to detect a first voltage drop (U12) to measure across the resistance element (6) and preferably parallel to the main current flow direction, and b) that the first voltage measuring contact (9) on the first connection part (2) together with the third voltage measuring contact (12) on the second connection part (3) form a second measuring channel (18) forms in order to measure a second voltage drop (U13) across the resistance element (6) and at an angle to the main current flow direction. Current measuring resistor (1) Claim 2 , characterized in that the second voltage measuring contact (11) on the second connection part (3) together with the third voltage measuring contact (12) on the second connection part (3) forms a third measuring channel (19) in order to cross a third voltage drop (U23) to measure the main current flow direction, in particular at right angles to the main current flow direction. Current measuring resistor (1) Claim 1 , characterized in , a) that the second voltage measuring contact (11) on the second connection part (3) together with the third voltage measuring contact (12) on the second connection part (3) forms a first measuring channel in order to generate a first voltage drop (U23) across the To measure the main current flow direction, in particular at right angles to the main current flow direction, and b) that the first voltage measuring contact (9) on the first connection part (2) together with the third voltage measuring contact (12) on the second connection part (3) forms a second measuring channel around a second Measure the voltage drop (U13) across the resistor element (6) at an angle to the main current flow direction. Current measuring resistor (1) Claim 4 , characterized in that the first voltage measuring contact (9) on the first connection part (2) together with the second voltage measuring contact (11) on the second connection part (3) forms a third measuring channel in order to generate a third voltage drop (U12) across the resistance element (6 ) and should preferably be measured parallel to the main current flow direction. Current measuring resistor (1) according to one of the preceding claims, characterized in , a) that a fourth voltage measuring contact is arranged (10) on the second connection part (3), which is electrically connected to the third voltage measuring contact (12) to collect the voltage to measure the third voltage measuring contact (12) and at the fourth voltage measuring contact (10), and / or b) that a fifth voltage measuring contact (22, 23) is arranged on the first connection part (2), which is electrically conductive with the first voltage measuring contact (9 ) is connected in order to measure the voltage jointly at the first voltage measuring contact (9) and at the fifth voltage measuring contact (22, 23). Current measuring resistor (1) according to one of the preceding claims, characterized in that a) that the first voltage measuring contact (9) in the first connection part (2) is arranged centrally with respect to the side edges of the current measuring resistor (1), in particular with an eccentricity that is smaller than 50%, 40%, 30%, 20%, 10% or 5% of the width of the current measuring resistor (1), and / or b) that the second voltage measuring contact (11) and the surrounding first incision (13) in the second connection part (3) are arranged centrally with respect to the side edges of the current measuring resistor (1), in particular with an eccentricity that is less than 50%, 40% , 30%, 20%, 10% or 5% of the width of the current measuring resistor (1), and / or c) that the third voltage measuring contact (12) is arranged eccentrically in the second connection part (3), and / or d) that the The first voltage measuring contact (9) in the first connection part (2) and the second voltage measuring contact (11) in the second connection part (3) have essentially the same distance from the side edges of the current measuring resistor (1), so that the first voltage drop (U12) over the resistance element (6) is measured parallel to the main current flow direction, and / or e) that in the second connection part (3) the third voltage measuring contact (12) and the fourth voltage measuring contact are essentially the same distance from the central axis se of the current measuring resistor (1). Current measuring resistor (1) according to one of the preceding claims, characterized in that the second voltage measuring contact (11) is arranged in the second connection part (3) between the third voltage measuring contact (12) and the fourth voltage measuring contact. Current measuring resistor (1) according to one of the preceding claims, characterized in that the first incision (13) in the second connection part (3) is arcuate, in particular U-shaped or V-shaped, with a base transverse to the main current flow direction and legs (15) , 16), which face the resistance element (6) essentially parallel to the main current flow direction. Current measuring resistor (1) Claim 9 , characterized in , a) that the legs (15, 16) of the first incision in the main current flow direction protrude into the resistance element (6) and end in the resistance element (6), the legs (15, 16) of the first incision optionally different project far or the same into the resistance element (6), in particular with a leg length (dx) within the resistance element (6) of a1) at most 3mm, 2mm, 1.5mm or 1mm, and / or a2) at least 0.1mm, 0 , 2mm, 0.5mm or 1mm, b) that the legs (15, 16) of the first incision in the main current flow direction end in front of the resistance element (6) in the second connection part (3), in particular at a distance from the resistance element (6) of b1) at most 3mm, 2mm, 1.5mm or 1mm, and / or b2) at least 0.1mm, 0.2mm, 0.5mm or 1mm. c) that the legs (15, 16) of the first incision end in the main current flow direction at the boundary between the resistance element (6) and the second connection part (3). Current measuring resistor (1) according to one of the preceding claims, characterized in that a) that in the second connection part (3) the second voltage measuring contact (11) and the surrounding first incision (13) are arranged eccentrically, and / or b) that in the second Connection part (3) the first incision (13) starts from a side edge of the current measuring resistor (1) and extends in an arc or L-shape into the resistance element (6) or at least up to the boundary between the second connection part (3) and the Resistance element (6). Current measuring resistor (1) according to one of the preceding claims, characterized by a) a second incision (24) in the second connection part (3) for influencing the temperature behavior of the resistance value, the second incision (24) in the second connection part (3) a current flow across the second incision (24) prevents, and b) a third incision (25) in the first connection part (2) to influence the temperature behavior of the resistance value, the third incision (25) in the first connection part (2) a current flow across via the third incision (25), and c) optionally a fourth incision (27) in the first connection part (2) for generating a further tension mesh and / or for influencing the temperature behavior of the resistance value, the fourth incision (27) in the first connection part (2) prevents current flow across the fourth incision (27). Current measuring resistor (1) Claim 12 , characterized in that a) that the second incision (24) starts from a lateral edge of the second connection part (3) opposite the first incision (13), b) that the third voltage measuring contact (12) in the second connection part (3) on the same lateral edge of the second connection part (3) is arranged like the second incision (24), c) that the third voltage measuring contact (12) is arranged in the second connection part (3) between the resistance element (6) and the second incision (24), d) that the third incision (25) starts from the side edge of the first connection part (2) on the same side as the first incision (13), e) that the first voltage measuring contact (9) in the first connection part (3) on the same side edge of the first connection part (2) is arranged like the second incision (25), f) that the first voltage measuring contact (9) is arranged in the first connection part (3) between the resistance element (6) and the third incision (25), g) that the optional fourth incision (27) in the first connection part (2) extends from the lateral edge of the first connection part (2) opposite the third incision (25), and / or h) that optionally a fourth voltage measuring contact on the first connection part (2) (26) is provided, the fourth voltage measuring contact (26) being arranged between the fourth incision (27) and the resistance element (6). Current measuring resistor (1) Claim 12 or 13th , characterized in that a) that the second incision (24) is L-shaped or arc-shaped or straight and optionally runs transversely to the main flow direction, and / or b) that the third incision (25) is L-shaped or arc-shaped or straight and optionally runs transversely to the main flow direction, and / or c) that the fourth incision (27) is L-shaped or arc-shaped or straight and transversely to the main flow direction, and / or d) that the second incision (24) is in the second connection part (3 ) extends up to or into the resistance element (6) or ends in the second connection part (3) in front of the resistance element (6), and / or e) that the third incision (25) in the first connection part (2) extends up to or extends into the resistance element (6) or ends in the first connection part (2) in front of the resistance element (6), and / or f) that the fourth incision (27) in the first connection part (2) extends up to or into the resistance element ( 6) extends or in which he Most connecting part (2) ends in front of the resistance element (6). Current measuring resistor (1) according to one of the Claims 12 until 14th , characterized in that a) the second incision (24) has substantially the same length as the third incision (25), or b) that the second incision (25) has a different length than the third incision (24). Current measuring resistor (1) according to one of the Claims 12 until 15th , characterized in that a) the first incision (13) has substantially the same length as the fourth incision (27), or b) that the first incision (13) has a different length than the fourth incision (27). Current measuring resistor (1) according to one of the preceding claims, characterized in that a) that the conductor material of the connection parts (2, 3) is copper, a copper alloy, aluminum or an aluminum alloy, and / or b) that the conductor material of the connection parts (2, 3 ) has a lower specific electrical resistance than the resistance material of the resistance element (6), and / or c) that the resistance material of the resistance element (6) is one of the following alloys: c1) a copper alloy, in particular a copper-manganese-tin Alloy, in particular CuMn12Ni2 or CuMn7Sn2,3, or a copper-manganese-nickel alloy, in particular Cu84Ni4Mn12 or Cu65Mn25Ni10, or a copper-chromium alloy, c2) a nickel alloy, in particular NiCr or CuNi, and / or d) that the resistance element (6) is electrically and mechanically connected to the two connection parts (2, 3), in particular by a welded connection, in particular by an electron beam welding, and / or e) that the resistance material has a specific electrical resistance which is less than 2 · 10 ^-4 Ω · m, 2 · 10 ^-5 Ω · m or 2 · 10 ^-6 Ω · m, and / or f) that the resistance material has a specific electrical resistance that is greater than 2 · 10 ^-6 Ω · m, 2 · 10 ^-7 Ω · m, and / or g) that the conductor material has a specific electrical resistance that is smaller as 10 ^-6 Ω · m or 10 ^-7 Ω · m, and / or h) that the current measuring resistor (1) has a low resistance with a resistance value of at most 1 µΩ, 10 µΩ, 20 µΩ, 33 µΩ, 50 µΩ, 100 µΩ, 500 µΩ, 10 mΩ, 5 mΩ, 2 mΩ or 1 mΩ, and / or i) that the current measuring resistor (1) has a current rating of at least 1A, 10A, 100A, 1kA or 5 kA, and / or j) that the resistance element (6) is plate-shaped, in particular as a flat plate, and / or k) that the connection parts (2, 3) are each plate-shaped, in particular as a flat plate, and / or I) that the current measuring resistor (1) in the Main current flow direction has a length that is smaller than 30cm, 20cm or 10cm, and / or m) that the current measuring resistor (1) at right angles to the main current flow direction has a width that is smaller than 20cm, 10cm or 5cm, and / or n) that the Current measuring resistor (1) has a thickness that is less than 10 mm, 5 mm, 4 mm, 2 mm or 1 mm, and / or o) that the two connection parts (2, 3) each have at least one power connection (4, 5) in order to introduce or discharge the current (I), the individual current connections preferably each having at least one bore (4, 5) in the respective connection part, and / or p) that the individual voltage measuring contacts are each contact pads, which consist of an electrically conductive coating on the respective connection part, and / or q) that the individual contact pads are each essentially rectangular, and / or r) that the coating of the contact pads is different Conductor material consists of the connection parts (2, 3) and / or s) that a trim cut is made on one or both sides of the resistance element (6) in order to measure the resistance value of the current measuring resistor (1) and / or the temperature coefficient of the resistance value of the current measuring resistor (1 ), t) that the current measuring resistor (1) optionally has voltage measuring contacts for exactly two or exactly three measuring channels, u) that optionally three voltage measuring contacts (9, 11, 12) are provided which have a three-point tap on a closed mesh on the first connection part ( 2) on the one hand and on the second connection part (3) on the other hand, the three-point bgriff provides three measuring channels (17-19) that deliver three voltage measured values (U12, U13, U23) to enable fault diagnosis. Current measuring device with a) a current measuring resistor (1) according to one of the preceding claims and b) a voltage measuring device (20) for separate voltage measurement in the first measuring channel (17) and in the second measuring channel (18) and optionally additionally in the third measuring channel (19), and c) an evaluation unit (21) c1) to determine the current (I) flowing through the current measuring resistor (1) from the voltage measured values (U12, U13, U23) in the various measuring channels (17-19), and / or c2) to diagnose a measurement error by evaluating the voltage measurement values (U12, U13, U23) in the various measurement channels (17-19). Current measuring device according to Claim 18 , characterized in , a) that the voltage measuring device (20) measures the following voltages: U12: Voltage between the first voltage measuring contact (9) on the first connection part (2) and the second voltage measuring contact (11) on the second connection part (3), U23: Voltage between the second voltage measuring contact (11) on the second connection part (3) and the third voltage measuring contact (12) on the second connection part (3), U13: Voltage between the first voltage measuring contact (9) on the first connection part (2) and the third Voltage measuring contact (12) on the second connection part (3), b) that the evaluation unit (21) calculates the following deviation ΔU from the voltages U12, U23 and U13: ΔU = U12 + U23 - U13, and c) that the evaluation unit generates an error signal if the deviation ΔU exceeds a permissible maximum value.

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