EP2817641A1

EP2817641A1 - Current sensor for fastening on a busbar

Info

Publication number: EP2817641A1
Application number: EP13701108.6A
Authority: EP
Inventors: Jens Nowotnick; Boris Adam; Michael Munz
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2012-02-24
Filing date: 2013-01-25
Publication date: 2014-12-31
Also published as: CN104160284A; DE102012202826A1; WO2013124117A1

Abstract

The present invention relates to a current sensor for fastening on a busbar (S) comprising a Hall sensor (2) which is encapsulated in a plastic housing (3), wherein the surface of the plastic housing (3) is designed to be mounted on the busbar (S) and connected thereto in a form-fitting and/or force-fitting and/or firmly bonded manner in a direction perpendicular to the longitudinal direction of the busbar (S), more particularly in a predefined position relative to said busbar.

Description

description

title

Current sensor for mounting on a busbar Prior art

The present invention relates to a device, in particular a

Current sensor for measuring a current flowing in a current-carrying conductor arrangement, in particular a busbar. In the course of

Electrification of individual passenger transport will be current sensors for the

Monitoring and control of the electrical components of vehicles needed, which detect the current flowing in individual conductors current and forward corresponding signals to an evaluation. So far, this increasingly arrangements were used, which enclose a current-carrying conductor, by means of a flux concentrator surrounding him

Magnetic field and to close from a magnetic field measurement on the amount of current through the conductor. FIG. 1 shows an arrangement in which a respective current sensor encloses a phase of a three-phase electrical system. On a printed circuit board L for this purpose current sensors 1 a, 1 b and 1 c are arranged, which receive substantially parallel to the surface of the printed circuit board L oriented busbars S. The current sensors 1 a, 1 b and 1 c have to the concentration of the current rails S surrounding magnetic flux (not shown) flux concentrators. Known

Flux concentrators can be made of stamped laminated cores or sintered material. Thus, the bundled in the flux concentrators

magnetic flux are evaluated by means of known principles of action and set in relation to the current causing it.

For use in modern electrically powered vehicles such current sensors are basically usable. However, the busbars installed in these vehicles are sometimes severely bent and / or twisted, so that the opening to be provided in the current sensors for the busbars must be made larger than actually necessary in order to place the current sensor as desired after completion of the busbar. Alternatively or additionally, the time of application of the current sensor to the busbar should be considered carefully, as it may not be possible at all to apply the current sensor after bending the busbar. It is therefore desirable to have a current sensor which has a low overall volume, is flexible to install and position, and is suitable for mass production in electric vehicles due to low production costs.

Disclosure of the invention

To satisfy the existing need, the present suggests

Invention, a current sensor with the features according to claim 1 before.

Accordingly, the current sensor comprises a Hall sensor, which is encapsulated in a plastic housing. The plastic housing can be manufactured in a known method step called "Molding" and already contain the Hall sensor and its connection lines

Busbar to be attached laterally. Contrary to the state of the art, it is therefore not necessary to slide the current sensor onto the busbar. In other words, the surface of the plastic housing may have a lateral abutment surface for attachment to a bus bar, so that the current sensor is substantially in a direction perpendicular to the

Longitudinal direction of the busbar to which it is to be attached, can be applied. For producing an exact, predefined relative position between the current sensor and the busbar, the contact surface of the plastic housing may have a recess or be located in a recess or cavity. In the assembly process, therefore, the busbar can be embedded in the edge of a current sensor according to the invention. An attachment between the busbar and the current sensor can take place in different ways: It can be a

Clamping connection between the components are generated by the

Plastic housing has clamping elements by means of which the busbar can be enclosed and held laterally. Here, the Clamping elements comprise latching elements, by means of which edges the

Busbar be undercut. Alternatively or additionally

Plug elements may be provided in the surface of the plastic housing, which penetrate recesses in a busbar and / or can undercut these. Alternatively or additionally, a material connection can be produced between the plastic housing and the busbar (for example by means of adhesive).

The dependent claims show preferred developments of the invention.

Advantageously, the current sensor according to the invention can be equipped with structural elements which are designed such that they correspond to the contour of a busbar. Thus, an exact positioning of the

Current sensor on the busbar reproducibly ensured and the alignment of the current sensor on the bus bar has low tolerances.

Preferably, so-called pins may be provided as structural elements in the surface of the plastic housing, which are adapted to penetrate an opening in a bus bar and back pressed, embossed and / or welded to produce a secure connection between the plastic housing and the busbar. The pins may, for example, have a substantially cylindrical cross-section and have a diameter in the range between 2 and 8 mm. Frequently used cross sections for copper busbars range between 20 and 60 mm ² to accommodate the currents found in automotive applications. Accordingly, the dimensions of the recess for the busbar in the plastic housing between 10 mm and 25 mm in width and preferably in the range between 13 to 18 mm wide and in the range 0 to 8 mm depth, in particular in the range 3 to 6 mm depth. Of course, the locking hooks and / or (plastic) pins can have a greater overall length for securely fixing the busbar in order to undercut the received busbar at the rear.

More preferably, one or more dimensionally measuring Hall sensors can be used, for example, interference or foreign magnetic fields recognize and take into account. Preferably comprises

according to the invention, at least two Hall sensors, whereby e.g. a difference analysis can be done. This makes it possible to identify disturbing influences and also to be able to carry out an evaluation of the magnetic field on the basis of a larger database. In addition, redundant measurement results in fail safety, which also ensures operation in the

Error continues to allow.

More preferably, the plastic housing in addition to a

Include evaluation circuit, which is adapted to receive from the Hall sensor or the Hall sensors derived signals and evaluate. For example, simply adding both signals can increase the sensitivity of the signal. Alternatively, a subtraction of certain signals can make fault influences recognizable. For this purpose, the evaluation circuit may comprise a so-called microcontroller, which means by the

Plastic housing led connecting cables is supplied with electrical energy. In addition, the microcontroller can be set up

Send evaluation results in data form to the periphery of the current sensor. This can also be wired and / or wireless. Likewise, within the plastic housing, a microcontroller or the

Evaluation circuit associated with network controller (e.g., Can controller) assigned, by means of which the current sensor could send evaluation results directly to a local bus system. The transmission of electrical energy and information at

Plastic housing of the current sensor existing connection lines may in particular be arranged to be connected directly to terminals on a printed circuit board. Alternatively or additionally, plug contacts may be present on the plastic housing and / or on the connecting lines themselves for a particularly simple contacting. In order to be able to compensate, for example, for vibrations induced mechanical stresses, the connection lines can be equipped with expansion areas or similar sections which, for example, have a meandering design

Have line geometries. Since a flux concentrator according to the present invention is not provided, a current sensor according to the invention may consist of a combination of features as described above. In other words, one of the exemplary embodiments does not require substantially more technical features than those discussed. By dispensing with a flux concentrator, the production costs of a current sensor are reduced and the complexity of the current sensor decreases

Manufacturing process and the variety of parts and a "threading" of the

Current sensor on a power rail is unnecessary. In addition, the am

Plastic housing provided structure for positioning and fastening of

Current sensor on the busbar exactly to that position

Track to be adapted to which the current sensor is to be finally arranged and operated. This results in the ability to position current sensors faster and more cost-effective on busbars and to obtain more precise measurement results over the prior art.

According to a further aspect of the present invention, an assembly for power electronics of an electrically operable vehicle for

Provided that at least one busbar and one on the

Busbar arranged current sensor, as has been described in detail above. In particular, the current sensor of the assembly may be disposed on a portion of the bus bar located near the power cell of the vehicle or near an electrical converter

(DC three-phase alternating current) is located.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawings:

1 shows a schematic diagram of conventional current sensors

a three-phase system;

Figure 2 is a perspective view of an embodiment according to the present invention; Figure 3 is a spatial representation of an alternative

Embodiment of the present invention;

4a shows a cross section through a current sensor according to the invention on a busbar in frictional connection;

Figure 4b shows a cross section through a current sensor according to the invention on a busbar in positive connection;

Figure 4c shows a cross section through a current sensor according to the invention on a busbar in material-locking connection;

Figure 5 is a spatial representation of an alternative

Embodiment of the present invention.

Embodiments of the invention

Figure 2 shows a current sensor 1 according to the invention with a first and a second Hall sensor 2. As shown enlarged, the Hall sensors 2 are designed as 3D Hall elements. Both Hall sensors 2 are on

opposite ends of a transfer mold arranged as a plastic housing 3. The plastic housing has a substantially cuboid basic shape. The cuboid is designed to save space very flat, so has a small thickness in the vertical direction. His length

(Corresponding to the current flow direction through the busbar S) is made slightly larger than its depth, so that the Hall sensors 2 are reliably enclosed by the housing 3. The width of the plastic housing 3 is chosen so that the opposing Hall sensors 2 can be arranged on opposite sides of the busbar S. In the area between the Hall sensors 2 is a recess 4 in

Plastic housing 3 is provided, which corresponds to the cross-sectional area of the busbar S substantially. In other words, the recess 4 is arranged in the longitudinal direction of the plastic housing on its underside such that the busbar S at least halfway (half of its cross-section) enclosed by the recess 4 of the housing 3 can be. In the exemplary embodiment, the recess 4 for this purpose, a first edge 4a and a second edge 4c, which are arranged in a substantially vertical direction. Both end in the bottom 4b of the recess 4. In other words, the first edge 4a and the second edge 4c of

Recess 4 set up, pressure forces on each other

Flanks of the busbar S exercise. From the bottom 4b of the recess 4 protrudes substantially perpendicularly a plastic pin 5, which is adapted to penetrate a hole 6 in the busbar S. At the head of the pin 5, a locking element for locking the busbar S is indicated. From the bottom of the plastic housing stand each next to the recess 4 wire pins 8 as electrical connection lines for the Hall sensors 2 out. For the sake of clarity, by way of example only, a wire pin 8 of a respective Hall sensor 2 has an expansion section 9 for compensation of mechanical stress

Voltages or for picking up vibrations during operation.

FIG. 3 shows an alternative embodiment of the arrangement shown in FIG. In contrast to Figure 2, Figure 3 shows no recess 4 in the plastic housing 3 of the current sensor 1. Instead, the

Plastic housing 3 two plastic pins 5a and 5b, by means of which the plastic housing 3 can be arranged in a predefined relative position on the busbar S. For connection to the plastic housing 3, the busbar S corresponding holes 6a and 6b, through which the plastic pins 5a and 5b can be inserted. A torsion-proof relative positioning and fastening is thus independent of the width of the

Busbar S (indicated by dashed lines) possible.

FIG. 4a shows a cross section through a current sensor 1 according to the invention, in which a bus bar S is arranged in a recess 4 and the underside of which is undercut by latching elements 5c of the housing 3. On the left and on the right side of the busbar S are at about their height

Top each a first and a second Hall sensor 2 are arranged. The illustration shown is an example of a non-positive connection, in which additionally undercut elements 5c for a secure

Form fit of the current sensor 1 with the busbar S can provide. FIG. 4b shows an alternative attachment possibility to the arrangement shown in FIG. 4a. The recess 4 in the plastic housing 3 here has a larger cross-section than that of the busbar S, so that a frictional connection between the flanks 4a and 4c of the recess and the flanks of the busbar S is not present. In order nevertheless to ensure an exact positioning between the current sensor 1 and the busbar S, a pin 5 of the plastic housing 3 is inserted through the busbar S and undercuts its underside by a locking element 5c. For torsion-proof mounting of the current sensor 1 on the busbar S, as shown in FIG. 3, a (not visible) second pin 5 from the direction of the viewer behind the cut pin 5 is arranged lying.

FIG. 4c shows an alternative attachment possibility between a current sensor 1 according to the invention and a busbar S. The underside of the housing 3 is substantially planar in order to be able to correspond to a large variety of busbars. A busbar S is arranged by way of example on the underside of the plastic housing 3 and fixed by means of an adhesive connection 10 symmetrically to the two Hall sensors 2. For exact positioning marks (not shown) may be provided on the plastic housing 3, based on which an exact

Positioning between the busbar S and the current sensor 1 in the course of assembly can be made. In particular, when using automated connection techniques can of course be dispensed with an optical marking, while still a precise

Positioning of the busbar relative to the Hall sensors 2 can be made.

Figure 5 shows a perspective view of an alternative embodiment of the present invention, in which the plastic housing 3 a

Microcontroller 7 as an evaluation circuit comprises. This is furnished, the

Conditioning signals of the Hall sensors 2, to compare with each other, to interpret and / or evaluate and forward. For this purpose, the Hall sensors 2 can be connected via lines (not shown) to the microcontroller 7, via which measurement signals are transmitted. In addition, the Hall sensors 2 can be supplied with electrical energy via these or separate lines from the microcontroller 7. Such a power supply can Of course, take place independently of the microcontroller 7. Also, the microcontroller 7 can be supplied via lines with electrical energy. Depending on the size of the current sensor 1 according to the invention, the

Plastic housing 2 also comprise a (not shown) energy converter, for example, voltage of a certain height or frequency

(In particular DC voltage) for the operation of the current sensor 1 according to the invention provide. For transmission of information obtained, the microcontroller 7, a wireless and / or wired

Be assigned communication interface, which may in particular also be arranged in the plastic housing 3. They can win over these

Information to the power control ("energy master") of the device comprising the busbar S are transmitted and the operations on the or in the busbar thus the control of the device are based.The advantage of an integration of logic in the current sensor according to the invention, that fewer separate functional units and assembly steps are required.

Optionally, other sensors such as e.g. Temperature, light and

Moisture sensors are integrated into a current sensor 1 according to the invention, in order to obtain further information about ambient and operating conditions by means of only one sensor unit. These additional sensors can also be used e.g. be powered and controlled via the microcontroller 7. Likewise, the data obtained by them can be interpreted by the microcontroller 7, evaluated and correlated with other data (e.g., stream data), in particular for the purpose of plausibility. This applies in particular to the temperature at the busbar S and they

flowing current.

A central idea of the present invention is to provide a current sensor 1 which can be optionally arranged at a predefined position of a busbar without threading it onto the busbar and having to push it over the edge of the busbar. For this purpose, the present invention offers various possibilities of relative positioning and connection between the current sensor and the busbar, due to which a lateral attachment of the current sensor according to the invention to a

Power rail S is made possible. Here, the present invention omits the use of a flux concentrator, which according to the prior art at least approximately encloses a bus bar whose current intensity is to be measured. If previous embodiments and features of the present

Invention have been described in detail, so this serves the

By way of illustration, far-reaching combinations are possible, in particular between the illustrated embodiments, all of which are to be understood as being within the scope of the present invention as defined by the appended claims.

Claims

claims

1 . Current sensor for attachment to a busbar (S) comprising a Hall sensor (2) which is encapsulated in a plastic housing (3), wherein the surface of the plastic housing (3) is arranged in a direction perpendicular to the longitudinal direction of the busbar (S) to the Busbar (S), in particular in predefined relative position to this, attached and positively and / or non-positively and / or materially connected to this.

2. Current sensor according to claim 1, wherein the plastic housing (3) has one or more structural elements (4a, 4b, 4c; 5a, 5b) for attachment and / or as positioning aids for predefined orientation on the busbar (S).

3. Current sensor according to claim 2, wherein a pin (5a, 5b) on the surface of the plastic housing (3) and / or a recess (4) in the surface of the plastic housing (3) is provided as a structural element.

4. Current sensor according to one of the preceding claims, wherein a

Recess with dimensions between 10 mm to 25 mm, preferably 13 to 18 mm, width and 0 to 8 mm, in particular 3 to 6 mm depth in the surface of the plastic housing (3) is provided.

5. Current sensor according to one of the preceding claims, wherein the

Plastic housing (3)

- An element (5a, 5b) for penetrating corresponding

Recesses (6a, 6b) in a busbar (S) and / or circuit board (L) is provided and / or

- Is provided an element (4a, 4c) for entering a clamping connection and / or a latching connection with a busbar (S). Current sensor according to one of the preceding claims, wherein the

Hall sensor (2) for multi-dimensional, in particular three-dimensional (3D), measurement of a magnetic field is set up.

Current sensor according to one of the preceding claims, wherein the

Plastic housing (3) additionally

- Includes a second Hall sensor (2), and / or

- Includes an evaluation circuit, which is designed in particular in the form of a microcontroller (7), and / or is set up for the preparation, evaluation and transmission of information obtained.

Current sensor according to one of the preceding claims, further comprising connection lines (8a, b, c, d, e, f) for receiving electrical energy and / or receiving and / or emitting information, wherein the connection lines (8a, b, c, d, e, f) are in particular arranged to be directly connected to a periphery and / or to compensate for mechanical stresses between the current sensor (1) and its periphery.

Current sensor according to one of the preceding claims, which consists of one of the combinations of features defined in the preceding claims.

Assembly, in particular for power electronics of an electrically operable vehicle, comprising at least one busbar (S) and one on the busbar (S) and arranged in particular geometrically to the busbar (S) adapted current sensor (1) according to any one of the preceding claims.