Electric current measurement module

Abstract

Electric current measurement module The invention relates to an electric current measurement module (2) intended to measure an electric current passing through an electrical conductor (8), the module (2) comprising a main winding (10) of electrically conductive wire, which further comprises a curved ferromagnetic element (12) having a rounded central portion (14) and two arms (16, 18) of the same length extending parallel to an axis of symmetry (X), on either side of the rounded central portion (14), the main winding (10) extending in a direction (Y) perpendicular to said axis of symmetry (X), and being disposed between said arms (16, 18) of the ferromagnetic element (12), so as to form a through housing adapted to surround said electrical conductor (8).This module (2) is configured to open in two parts, a first part comprising at least the main winding (10) and a second part comprising at least the rounded central portion (14). Figure for the abbreviation: Figure 1.

Description

Title of the invention: Electric current measurement module

[0001] The present invention relates to an electric current measurement module.

[0002] The invention lies in the field of devices for measuring electrical quantities.

[0003] Electrical installations, for example local electricity distribution networks, suitable for the distribution of electricity in a building, generally comprise several loads, and where appropriate several sources, connected by electrical conductors.

[0004] There is a need to ensure the supervision, proper functioning and safety of such electrical installations, and to do this, it is useful to provide means for measuring electrical quantities making it possible to characterize the electrical signals circulating in the electrical conductors, by measuring electrical quantities.

[0005] In particular, current measurement makes it possible to ensure safety by enabling the actuation of protective devices such as circuit breakers to be triggered.

[0006] Thus, the implementation of current measuring devices is a recurring problem in the field of supervision of electrical installations.

[0007] In the field of current measuring devices, in particular for measuring alternating current or current pulses, devices are known which use a helical winding of conductive wire, also called a coil, known as Rogowski sensors. The winding is preferably circular in shape, forming a ring inside which is positioned the electrical conductor through which the electric current to be measured flows. The voltage induced in the winding is proportional to the rate of change, in other words to the time derivative, of the current flowing in the conductor. The circular shape of the winding, with equidistant turns, has the best properties from a theoretical point of view, but is difficult to achieve in practice.

[0008] In variants, the current sensor is formed from several linear windings, arranged for example in a square and forming a central space for the passage of the electrical conductor. However, in such an arrangement it is difficult to guarantee the immunity of the sensor to current sources other than the electrical conductor whose current is to be measured. Conventionally, additional turns are placed in the corners to capture the flux in the corners.

[0009] There are opening Rogowski sensors, comprising windings on a flexible frame, which makes it easier to insert the electrical conductor centrally between the windings of the sensor, without having to disconnect the electrical conductor. This has the advantage of making it easier and saving time when installing such sensors.

[0010] However, known sensors of this type are not very compact, their size not allowing their integration into small electrical panels.

[0011] There is therefore a need to provide current measuring devices that are open, efficient and robust, while being easy to manufacture and compact.

[0012] To this end, the invention proposes, according to one aspect, an electric current measurement module intended to measure an electric current passing through an electric conductor, the module comprising a main winding of electrically conductive wire.This module further comprises a ferromagnetic element of curved shape, the ferromagnetic element comprising a rounded central portion and two arms of the same length extending on either side of the rounded central portion, the ferromagnetic element having an axis of symmetry parallel to each of the arms, the main winding extending in a direction perpendicular to said axis of symmetry, and being arranged between said arms of the ferromagnetic element, so as to form a through housing adapted to surround said electrical conductor, the measurement module being configured to open in two parts, a first part comprising at least the main winding and a second part comprising at least the rounded central portion of the ferromagnetic element, to allow insertion of said electrical conductor between the two parts.

[0013] Advantageously, the proposed electric current measuring module is compact and robust, thanks to the arrangement of the main winding and the associated ferromagnetic element.

[0014] The current measurement module according to the invention may have one or more of the characteristics below, taken independently or in any acceptable combination.

[0015] The main winding is made by winding a conductive wire onto a linearly shaped support.

[0016] Each of said arms has one end located opposite the rounded central portion, and the main winding is arranged at the same distance, in the direction of the symmetrical axis, from the end of each arm.

[0017] The first part is formed by the main winding and the second part is formed by the ferromagnetic element.

[0018] The rounded central portion of the ferromagnetic element forms said second part, separable from each of said arms, the first part being formed by the arms and the main winding fixed between said arms.

[0019] The main winding has a first end and a second end, said arms of the ferromagnetic element being respectively a first arm and a second arm, the measuring module further comprising compensation windings, arranged on either side of the main winding, respectively between the first end of the main winding and the first arm and between the second end of the main winding and the second arm.

[0020] The rounded central portion has a rectangular shape with rounded corners in a longitudinal plane of the ferromagnetic element.

[0021] The rounded central portion has the shape of an arc of a circle in a longitudinal plane of the ferromagnetic element.

[0022] The ferromagnetic element is an alloy of iron-silicon or iron-nickel.

[0023] The module further comprises a processing circuit, the conductive wire of the main winding being connected to the processing circuit, the processing circuit comprising in particular an integrator of the electrical signal.

[0024] Other characteristics and advantages of the invention will emerge from the description given below, for information purposes only and in no way limiting, with reference to the appended figures, among which:

[0025] [Fig-1] [Fig.l] schematically represents a current measurement module electric according to one embodiment;

[0026] [Fig.2] [Fig.2] represents a detail of [Fig.l];

[0027] [Fig.3] [Fig.3] schematically represents a current sensor of an electric current measurement module according to a variant.

[0028] Embodiments of an electric current measurement module are described below with reference to Figures 1 to 3.

[0029] [Fig.l] schematically illustrates a current measurement module 2 according to one embodiment, intended to continuously measure the current passing through the electrical conductor 8.

[0030] The electrical conductor 8 is part of an electrical installation (not shown) in which the current measurement module 2 can be positioned to carry out the current measurement.

[0031] The current measurement module 2 comprises an inductive current sensor 5 comprising a main winding 10 of conductive wire, also called main winding 10, for example of linear shape, i.e. produced by helical winding of the conductive wire around a support of linear shape. For example, the support has a circular section.

[0032] Alternatively, the shape of the winding may be curved, for example produced by helical winding of a conductive wire around a portion of torus.

[0033] The conductive wire is for example a copper wire, the support being made of plastic material, for example liquid crystal polymer (or LCP).

[0034] The sensor 5 further comprises a ferromagnetic element 12 of curved shape.

[0035] The sensor 5 thus formed is a so-called hybrid Rogowski sensor.

[0036] The ferromagnetic element 12 has an inverted “C” shape in the illustrated figures, comprising a rounded central portion 14, having an axis of symmetry X, and two arms, respectively a first arm 16 and a second arm 18 extending symmetrically, parallel to the axis of symmetry X of the rounded central portion 12.

[0037] Preferably, the two arms 16, 18 are linear and of the same dimensions, e.g. of the same length, thickness, height.

[0038] In the example illustrated, the arms 16, 18 have a rectangular section.

[0039] Each of the arms 16, 18 has a first end 11, 13 located opposite the rounded central portion and a second end 15, 17, opposite the first end 11, 13.

[0040] In one embodiment, as visible in the detail of [Fig.2], the rounded central portion 14 has a height hl and each of the arms 16, 18 has a height h2, the height h2 being less than hl.

[0041] Alternatively, the heights hl and h2 are equal, or the height h2 is greater than the height hl.

[0042] In one embodiment, the rounded central portion 14 and the arms 16, 18 have a thickness of ferromagnetic material, preferably between 0.3 mm and 4 mm.

[0043] In one embodiment, the ferromagnetic element 12 is formed as a plurality of stacked layers of material.

[0044] The ferromagnetic element 12 is for example made of steel, e.g. an iron-nickel or iron-silicon alloy, these materials having significant permeability.

[0045] In the illustrated embodiments, the main winding 10 is arranged along an axis Y, orthogonal to the axis of symmetry X, in spatial proximity to the second ends 15, 17 of the arms 16, 18.

[0046] For example, the main winding 10 is arranged at the same distance d greater than or equal to 1 mm, and preferably greater than or equal to 2 mm from the second ends 15, 17 of the arms 16, 18.

[0047] In one embodiment, the distance d is of the order of magnitude of the diameter of the main winding.

[0048] Thus, the arrangement of the main winding and the ferromagnetic element makes it possible to form a through housing 25 adapted to accommodate and surround the electrical conductor 8.

[0049] Preferably, the ferromagnetic element 12 has a geometric shape symmetrical with respect to the axis of symmetry X.

[0050] In the embodiment illustrated in Figures 1 and 2, the rounded central portion 14 has a rectangular shape with rounded corners, in a longitudinal plane of the ferromagnetic element 12 (X, Y plane in [Fig.l]).

[0051] The sensor 5 of the module 2 is arranged in two parts, so as to allow subsequent opening and closing, and consequently facilitate the positioning of the module 2 around the electrical conductor 8.

[0052] In the embodiment of [Fig.l], the arms 16, 18 are separable from the rounded central portion 14, which advantageously allows the sensor to be opened by separation between the arms and the rounded central portion, to allow an electrical conductor to be surrounded.

[0053] In other words, in this embodiment the sensor 5 is an opening sensor formed of two separable parts, allowing the opening and closing of the sensor around the electrical conductor.

[0054] In the embodiment of [Fig.l], the arms 16, 18 and the main winding form a first part of the sensor, the rounded central portion 14 of the ferromagnetic element 12 forming a second part of the sensor.

[0055] For example, the arms 16, 18 are fixed to the support of the main winding by rolling.

[0056] Several mechanical opening modes are possible between the first part and the second part of the sensor, for example by implementing a pivot, or by translation in association with a mechanical closing element (for example by snap-fastening).

[0057] The module 2 further comprises, in embodiments, compensation windings 20, 22, arranged on either side of the main winding 10, between each end 23, 25 of the main winding 10 and the arms 16, 18 of the ferromagnetic element 62, so as to ensure magnetic compensation of the mechanical clearances, in particular between the winding support and the ferromagnetic element.

[0058] The compensation windings 20, 22 are preferably symmetrical.

[0059] Each compensation winding 20, 22 comprises the same number of turns, this number being for example determined by measurement or simulation of the performance of the sensor, so as to optimize the performance. For example, disturbing conductors are placed close to the sensor during the simulation, and the number of turns of the compensation windings is that which makes it possible to obtain results that are the least sensitive to disturbing conductors.

[0060] For example, each compensation winding has between 80 and 100 turns.

[0061] All of the windings, i.e. the main winding 10 and the compensation windings 20, 22, form a winding or coil for measuring the electric current.

[0062] In one embodiment, the main winding is fixed to the respective arms 16, 18 by means of fixing pieces 26, which are for example made of plastic material, for example example of LCP (liquid crystal polymer).

[0063] Thus, in this embodiment, the arms 16, 18 and the main winding 10, optionally additionally comprising compensation windings 20, 22, form the first part of the sensor 5, and the rounded central portion 14 forms the second part of the sensor.

[0064] Advantageously, the performance of the sensor 5 is preserved during opening and closing, the separation of the two parts being carried out at the level of the ferromagnetic element.

[0065] The current measurement module 2 further comprises an electrical or electronic processing circuit 30, the current sensor 5 being connected to the processing circuit 30.

[0066] The processing circuit 30 is configured to process the electric current passing through the measuring winding, and notably comprises an integration module to obtain a measurement of the electric current passing through the electrical conductor 8.

[0067] For example, the processing circuit 30 comprises in particular an anti-aliasing filter, a digital-analog conversion block, a block for time integration of the electrical signal to obtain a measurement of current I(t) and a block for calculating electrical quantities, for example average or quadratic average values ​​of the electrical current.

[0068] Advantageously, when the ferromagnetic element has a shape such as illustrated in [Fig.l] and 2, with a rectangular profile, the current measurement module obtained is particularly compact, and particularly suitable for being integrated into a parallelepiped housing.

[0069] Such a case is easy to manufacture.

[0070] A second embodiment of a current sensor forming part of a current measurement module 2 is illustrated in [Fig.3].

[0071] In this embodiment, the sensor 5' comprises a ferromagnetic element comprising a rounded central portion 14' in the shape of an arc of a circle.

[0072] Nevertheless, other shapes with symmetry relative to the axis of symmetry X are conceivable, for example the rounded central portion 14' has a rectangular shape with rounded corners, as illustrated in [Fig.2].

[0073] In this second embodiment, the ferromagnetic element 12' is formed from a single piece, in other words the respective arms 16', 18' are integral with the rounded central portion 14'.

[0074] In this case, the opening of the sensor is carried out by translational movement along the X axis of the ferromagnetic element 12' relative to the main winding 10, where appropriate extended by the compensation windings 20, 22. Thus, in this embodiment, the measurement winding 10, 20, 22 forms the first part of the sensor 5', and the ferromagnetic element comprising the rounded central portion 14' and the arms 16', 18' forms the second part of the sensor 5'.

[0075] In all embodiments, the dimensioning of the ferromagnetic element 12 is chosen according to the expected performance and the acceptable size.

[0076] Advantageously, the current sensor 5 with dimensions of approximately 15mm x 5mm in the X,Y plane makes it possible to obtain a performance of the order of 250 mV / Amp at 50 Hz.

[0077] Advantageously, the current measurement module can be separated into two parts, and therefore it can be opened, which allows easy installation around an electrical conductor without having to disconnect this conductor.

[0078] Advantageously, the separation into two parts does not require opening the windings, which makes the current measurement module more robust to a number of openings and closings. Thus, its handling by an operator is easier.

[0079] Advantageously, the curved shape of the ferromagnetic element is optimized, which makes it possible to optimize the current measurement performance, while respecting space constraints.

Claims

Claims

1. Electric current measuring module (2) intended to measure an electric current passing through an electric conductor (8), the module (2) comprising a main winding (10) of electrically conductive wire, the current measuring module (2) being characterized in that it further comprises a ferromagnetic element (12, 12') of curved shape, the ferromagnetic element (12, 12') comprising a rounded central portion (14, 14') and two arms (16, 18, 16', 18') of the same length extending on either side of the rounded central portion (14, 14'), the ferromagnetic element (12, 12') having an axis of symmetry (X) parallel to each of the arms, the main winding (10) extending in a direction (Y) perpendicular to said axis of symmetry (X), and being arranged between said arms (16, 18, 16', 18') of the ferromagnetic element (12, 12'), so as to form a through housing (25) adapted to surround said electrical conductor (8),the measurement module (2) being configured to open into two parts, a first part comprising at least the main winding (10) and a second part comprising at least the rounded central portion (14, 14') of the ferromagnetic element (12, 12'), to allow insertion of said electrical conductor (8) between the two parts, characterized in that said rounded central portion (14) of the ferromagnetic element (12) forms said second part, separable from each of said arms (16, 18), said first part being formed by the arms (16, 18) and the main winding (10) fixed between said arms.,

2. Current measuring module according to claim 1, wherein the main winding (10) is made by winding a conductive wire on a linearly shaped support.

3. Current measurement module according to claim 1 or 2, wherein each of said arms (16, 18) has an end (15, 17) located opposite the rounded central portion (14), and wherein said main winding (10) is arranged at the same distance (d), in the direction (X) of the symmetrical axis, from the end (15, 17) of each arm (16, 18).

4. A current measuring module according to any one of claims 1 to 3, wherein the main winding has a first end and a second end, said arms of the ferromagnetic element being respectively a first arm (16) and a second arm (18), the measuring module further comprising compensation windings (20, 22), arranged on either side of the main winding (10), respectively between the first end of the main winding and the first arm and between the second end of the main winding and the second arm.

5. Current measuring module according to any one of claims 1 to 4, wherein the rounded central portion (14) has a rectangular shape with rounded corners in a longitudinal plane of the ferromagnetic element.

6. Current measuring module according to any one of claims 1 to 4, wherein the rounded central portion (14) has a circular arc shape in a longitudinal plane of the ferromagnetic element.

7. A current measuring module according to any one of claims 1 to 6, wherein said ferromagnetic element is an iron-silicon or iron-nickel alloy.

8. Current measurement module according to one of claims 1 to 7, further comprising a processing circuit (30), the conductive wire of the main winding being connected to the processing circuit (30), the processing circuit comprising in particular an integrator of the electrical signal.

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