Improved inductive position sensor

Abstract

The present invention relates to an inductive position sensor (1) for a rotating electrical machine comprising a printed circuit board (10) with two substrates (13, 14) on which are arranged at least one transmitting element (11) for emitting an oscillating magnetic field towards a rotating coupling element (20) to generate a modified magnetic field, and at least one receiving device (12) for detecting the modified magnetic field. The connections between the at least one transmitting element and the at least one receiving element to at least one signal processing element are made with conductive elements (101, 102) located on a region (30) different from that (40) where the transmitting elements (11) and receiving elements (12) are located. The sensor comprises a ground plane (17) positioned on the region (30) of the conductive elements so as to extend to the region (40) of the transmitting elements (11) and receiving elements (12). Fig. 2.

Description

Title of the invention: Improved inductive position sensor

[0001] The present invention relates to the field of position sensors, and more particularly to an inductive position sensor.

[0002] Inductive position sensors, known as eddy current sensors, use an oscillating magnetic field to determine the angular position of a rotating target which forms a coupling element.

[0003] These position sensors are notably used in electric motors of electric or hybrid vehicles comprising a rotor rotating relative to a stator.

[0004] The angular position of the rotor is determined relative to the stator. The target is mounted at the end of, or through, a shaft of the rotor to modify an oscillating magnetic field transmitted by a transmitter. The target is centered with respect to an axis of rotation of the rotor. The target comprises several vanes that provide a magnetic field pattern with respect to the axis of rotation of the rotor.

[0005] The position sensor is fixed relative to the stator, facing the target and around or facing the end of the rotor. The position sensor comprises a printed circuit board (PCB) having at least one emitting element for emitting an oscillating magnetic field towards the target, generating a modified oscillating magnetic field at a given frequency.

[0006] The printed circuit board includes at least one receiving device for detecting the modified oscillating magnetic field and transmitting it to a signal processing unit provided on the printed circuit board to deduce the angular position of the target. Typically, the coupling element has an outer diameter substantially identical to the outer diameter of the transmitting antennas.

[0007] However, in some cases, the sensor may need to be positioned facing different coupling elements, for example, with an outer diameter greater than the outer diameter of the transmitting / receiving antennas. A drawback of this situation is that when the coupling element is larger than the transmitting and receiving elements, significant interference occurs during angle measurement, degrading performance.

[0008] For sensors comprising only two substrate layers forming the electronic board, due to their configuration, the ground plane cannot be sufficiently extended to correct interference problems. Indeed, the ground plane cannot overlap certain electrical connections, for example, the conductive elements connecting the transmitting and / or receiving elements to the signal processing unit. Thus, in cases where the coupling element has a diameter with an exterior larger than that of the antennas, the conductive elements behave as a disturbing element in the measurement of the angle.

[0009] The present invention therefore aims to overcome one of the drawbacks of those of the prior art by proposing a position sensor whose configuration is improved to limit disturbances and improve performance.

[0010] To this end, the present invention proposes an inductive position sensor for a rotating electrical machine comprising a printed circuit board, with two substrates, on which are arranged at least one transmitting element intended to emit an oscillating magnetic field towards a rotating coupling element to generate a modified magnetic field, and at least one receiving device intended to detect the modified magnetic field, the connections between the at least one transmitting element and the at least one receiving element to at least one signal processing element are made with conductive elements located in a different area from that in which the transmitting and receiving elements are located,

[0011] the sensor comprising a ground plane positioned on the area of ​​the conductive elements so as to extend to the area of ​​the transmitting and receiving elements.

[0012] Thus, with the sensor according to the invention, when the coupling element overlaps the area of ​​the conducting elements, the conducting elements being encompassed in the ground plane, without being covered, they no longer behave as disturbing elements.

[0013] According to one embodiment of the invention, the ground plane is segmented into several portions arranged so as to surround the conducting elements without covering them.

[0014] According to one embodiment of the invention, the ground plane is arranged on two layers of substrate.

[0015] According to one embodiment of the invention, different portions of the ground plane are arranged on the first and second substrate layers and are connected to each other with metallic vias passing through the printed circuit board in its thickness to join another lower substrate.

[0016] According to one embodiment of the invention, a portion of conductive elements located on two different substrate layers of the electronic board are superimposed one with respect to the other.

[0017] According to one embodiment of the invention, a portion of conductive elements located on two different substrate layers of the electronic board are arranged so as not to overlap with each other.

[0018] The invention also relates to an electrical machine comprising a sensor according to the invention.

[0019] According to one embodiment of the invention, the rotating electric machine is an electric motor of an electric or hybrid vehicle comprising a rotor rotating relative to a stator.

[0020] The invention also relates to the use of the sensor according to the invention to measure the angular position of a rotor relative to a stator of an electrical machine.

[0021] Other objects, features and advantages of the invention will be better understood and will become more apparent upon reading the description given below, with reference to the accompanying figures, given by way of example and in which:

[0022] - Fig. 1 is a schematic representation of a sensor with two elements of different couplings, a) identical diameter b) diameter greater than the outer diameter of the transmitting antennas,

[0023] - [Fig.2] is a view of the superposition of the 2 substrate layers of the sensor according to a first embodiment of the invention,

[0024] - [Fig. 3] is a view of portions of a substrate layer of the sensor according to a second embodiment of the invention,

[0025] - [Fig. 4] is a view of portions of another substrate layer of the sensor according to a second embodiment of the invention,

[0026] - [Fig. 5] is a view of the superposition of the 2 substrate layers of the sensor according to a second embodiment of the invention.

[0027] The invention relates to an inductive position sensor 1, as illustrated in [Fig.1] to [Fig.5].

[0028] The inductive position sensor 1, associated with a visible coupling element 20 [Fig. 1], is intended to be mounted in a rotating electrical machine such as an electric motor of an electric or hybrid vehicle comprising a rotor rotating relative to a stator. The angular position of the rotor is determined relative to the stator.

[0029] The sensor includes an electronic board 10 on which are arranged at least one transmitting antenna 11, at least one receiving element 12 and at least one signal processing unit 13.

[0030] According to one embodiment of the invention, at least one receiving antenna is arranged inside at least one transmitting antenna.

[0031] During sensor operation, at least one transmitting antenna 11 emits an oscillating magnetic field at a given frequency. A coupling element 20 is positioned to modify this magnetic field. According to one embodiment of the invention, the coupling element is mounted on one end of a rotor shaft to modify the magnetic field emitted by the transmitting antenna 11. The modified magnetic field generates an electromotive force in the receiving element 12. This electromotive force is processed by the signal processing unit. 13 so as to provide output signals enabling the measurement of the position of the coupling element 20.

[0032] According to one embodiment of the invention, the coupling element 20 is a rotating element, for example with the rotor of the electric motor.

[0033] According to one embodiment of the invention, the coupling element has an outside diameter that is the same as or greater than the outside diameter of the transmitting antennas.

[0034] According to one embodiment of the invention, the electronic card 10 has openings 15 allowing connection to wires or metallic connection elements.

[0035] According to one embodiment of the invention, the number of windings of at least one receiving element 12 is proportional to the number of angular sectors of the casting element 20.

[0036] According to one embodiment of the invention, the electronic card 10 consists of two substrate layers.

[0037] According to one embodiment of the invention, the connections between the transmitting and receiving elements and to at least one signal processing element are made with conductive elements 101, 102.

[0038] According to one embodiment of the invention, the conductive elements 101, 102 are located on a zone 30 different from that 40 where the emission elements 11 and reception elements 12 are located.

[0039] According to one embodiment of the invention, the conductive elements 101, 102 are composed of a portion where the conductive elements 101, 102 are on the same substrate layer, and a portion 111, 112 where they are located on two different substrate layers of the electronic board 10, superimposed one on the other.

[0040] In the context of the invention, the sensor 1 comprises a ground plane 17 positioned on the area 30 of the conducting elements so as to extend to the area 40 of the transmitting elements 11 and receiving elements 12.

[0041] For this purpose, according to a first variant of the invention, the ground plane 17 is segmented 171, 172, 173, that is to say, it is formed of several portions 171, 172, 173 arranged so as to surround the conductive elements 101, 102 without ever covering them.

[0042] In the context of the invention, the mass plane 17 is arranged on two substrate layers 13, 14.

[0043] The various portions 171, 172, 173 of the ground plane are arranged on the first 13 and second 14 substrate layers and are connected to each other by metallic vias 174 passing through the upper substrate 13 in its thickness to join the lower substrate 14. The upper substrate 13 and the lower substrate 14 are defined with respect to the fact that the two substrates are superimposed. There is therefore a upper substrate and a lower substrate, regardless of the orientation of sensor 1.

[0044] According to an embodiment of the invention of this variant illustrated [Fig.2], the portion 111, 112 comprises conductive elements 101, 102 located on two different substrate layers 13, 14 of the electronic board are superimposed with respect to each other.

[0045] Thus, on each substrate, there is at least one portion of the ground plane 17 surrounding the conductive elements 101, 102. In this way, when the substrates are superimposed, thanks to the set of portions connected by the vias 174 [Fig. 5], a large part of the area 30 where the conductive elements 101, 102 are located is covered by the ground plane 17.

[0046] According to one embodiment of the invention, the ground plane 17 is segmented as in the first embodiment, and the conductive elements located on two different substrate layers 13, 14 of the electronic board of portion 111, 112 are arranged so as not to overlap. The conductive elements of portion 111, 112 are thus offset so that they are located on at least two substrate layers 13, 14 but without being superimposed on each other, as illustrated in [Fig. 5].

[0047] The offset of the conducting elements on each of the substrates allows the ground plane 17 to be extended over the two substrate layers 13, 14.

[0048] The ground plane 17 is thus made up of several portions 171, 172, 173 located on each of the two substrate layers 13, 14 of the electronic board 10. The portions 171, 172, 173 of the ground plane 17 are connected to each other by several metallic vias 174 passing through the thickness of the electronic board 10. That is to say, there is at least one portion on one substrate layer and one portion on another substrate layer.

[0049] Thus, with the sensor 1 according to the invention, when the coupling element superimposes the area of ​​the conducting elements, the conducting elements 101, 102 being encompassed in the ground plane, without being covered, they no longer behave as disturbing elements.

[0050] The invention also relates to an electrical machine comprising a sensor 1 as described above.

[0051] The scope of the present invention is not limited to the details given above and allows for embodiments in many other specific forms without departing from the field of application of the invention. Therefore, the present embodiments should be considered by way of illustration and may be modified without, however, departing from the scope defined by the claims.

Claims

Demands

1. An inductive position sensor (1) for a rotating electrical machine comprising a printed circuit board (10) with two substrates (13, 14) on which are arranged at least one transmitting element (11) intended to emit an oscillating magnetic field towards a rotating coupling element (20) to generate a modified magnetic field, and at least one receiving device (12) intended to detect the modified magnetic field, the connections between the at least one transmitting element and the at least one receiving element to at least one signal processing element are made with conductive elements (101, 102) located on a zone (30) different from that (40) where the transmitting elements (11) and receiving elements (12) are located, characterized in that it comprises a ground plane (17) positioned on the zone (30) of the conductive elements so as to extend to the zone (40) of the transmitting elements (11) and receiving elements (12),the ground plane (17) being segmented (171, 172, 173) into several portions (171, 172, 173) of ground plane arranged so as to surround the conducting elements (101, 102) without covering them.

2. Inductive position sensor (1) according to claim 1, wherein the ground plane (17) is arranged on two substrate layers (13, 14).

3. Inductive position sensor (1) according to claim 1 or 2, wherein different portions (171, 172, 173) of the ground plane are arranged on the first (13) and second (14) substrate layer and are connected to each other with metallic vias (174) passing through the printed circuit board (10) (13) in its thickness to join another lower substrate (14).

4. Inductive position sensor (1) according to any one of claims 1 to 3, wherein the conductive elements (101, 102) of a portion (111, 112) of conductive elements, located on two different substrate layers (13, 14) of the electronic board are superimposed with respect to each other.

5. An inductive position sensor (1) according to any one of claims 1 to 3, wherein the conductive elements (101, 102), of a portion (111, 112) of conductive elements, are located on two layers (13, 14) of Different substrates of the electronic board are arranged so that they do not overlap each other.

6. An electrical machine comprising a sensor (1) according to any one of claims 1 to 5.

7. Electric machine comprising a sensor (1) according to any one of claims 1 to 5, wherein the rotating electric machine is an electric or hybrid vehicle electric motor comprising a rotor rotating relative to a stator.

8. Use of the sensor according to any one of claims 1 to 5 for measuring the angular position of a rotor relative to a stator of an electrical machine.

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