Method for adjusting a measuring device comprising at least one position sensor

Abstract

The present invention relates to a method for adjusting a measuring device comprising positioning the measuring device on the stator (3), securing the device to the stator by means of fastening elements (12), a first rotation of the rotor, measurement of its signal and a signal from the sensor, calculation of a phase angle, rotation of a base (14) of the device, a second rotation of the rotor, calculation of a second phase angle, in the case where the second phase angle lies outside a certain range, an iteration of the preceding steps is performed, and securing the measuring device to the stator. Abstract figure: Figure 1

Description

Title of the invention: Method for adjusting a measuring device comprising at least one position sensor Technical field

[0001] The present invention relates to the field of rotating electrical machines such as electric motors or electric generators for electric or hybrid motor vehicles.

[0002] The invention relates more specifically to adjustment devices for such rotating electrical machines and more particularly to a method of adjusting such a measuring device comprising a position sensor of a rotating electrical machine. STATE OF THE ART

[0003] Generally speaking, a rotating electrical machine, for example a polyphase alternating current motor, comprises a stator which is a fixed part relative to a frame, for example a platform of an electric or hybrid vehicle, and a rotor which is a mobile part in rotation relative to the stator. Polyphase alternating current electric motors are generally classified into two main categories, so-called synchronous machines and so-called asynchronous machines, also called induction motors.

[0004] In the case of synchronous machines, the rotor has a magnetic field generated either by permanent magnets distributed on the periphery of a rotor shaft, or by conductors wound around ferromagnetic materials and powered by a DC voltage source also carried by the rotor, called electromagnets. The stator comprises several phases, to each of which is connected at least one coil, also called a winding, powered by current and voltage. Permanent magnet synchronous motors are known to those skilled in the art by the acronym "PMAC" for "Permanent Magnets AC motors". PMACs are generally more efficient and more compact than induction motors, depending on the quality of the permanent magnets used, in particular if they are permanent magnets based on a Neodymium-Fe-Boron alloy "NdFeB", or based on a Samarium-Cobalt alloy "SmCo".

[0005] To control such PMAC motors and achieve high and precise performance, it is necessary to know the angular position and speed of the rotor in real time. These performances are necessary, particularly in automotive applications of such motors.

[0006] The angular position of the rotor relative to the stator windings is generally given by a position sensor linked to the stator and a rotating target mechanically linked to the rotor, for example one of the rotor magnets. These sensors are for example Hall effect type sensors or inductive sensors. Such sensors need to be calibrated, because the value corresponding to the electrical zero of said sensor depends on the type of sensor, its mounting on the rotor or even the moment of power-up and is by default different from the actual value of the electrical zero corresponding to the angular orientation between the stator and the rotor for which the electromotive force is zero.

[0007] This operation is essential to guarantee the performance of the electrical machine, because practice shows by way of example that a 1° offset between the stator and the rotor leads to a torque drop of approximately 5%, and a 2° offset leads to a torque drop of around 20% compared to a nominal value.

[0008] Various electrical or software methods are known in the state of the art for correcting the angular orientation of the sensor so that the electrical zero of the orientation of the rotor relative to the stator measured by the sensor corresponds, as faithfully as possible, to the actual orientation. However, these methods have the disadvantage of having to be carried out again, for example when an inverter connected to the electrical machine must be changed, or during maintenance operations. Thus, it is necessary to disconnect the rotor from the mechanical transmission chain to drive it using an external tool or, in certain applications, in particular in the case of an electric or hybrid vehicle engine, to drive the wheels of said vehicle in rotation, which requires an operation of lifting said vehicle. These constraints make each additional adjustment of the position sensor tedious, expensive and redundant.Finally, electrical or software adjustments have the particularity of being more complex to carry out, and therefore more expensive.

[0009] The invention therefore aims to remedy all or part of the drawbacks of the state of the art, in particular by proposing a mechanical method for adjusting a simple position sensor and, in particular, only needing to be implemented during the first commissioning of a permanent magnet synchronous electric machine. PRESENTATION OF THE INVENTION

[0010] More specifically, the subject of the invention is a method for adjusting a measuring device comprising at least one position sensor for a rotating electrical machine, comprising a rotor and a stator, the method comprising: • the positioning of the measuring device on the stator, opposite a target fixed to the rotor defining an original orientation; • fixing the measuring device on the stator by fixing elements of the measuring device, in an adjustment position of said fixing elements • a first rotation of the rotor around an axis of rotation of the rotor by a shaft external to the electric machine for a determined number of revolutions of the rotor; • measuring an electrical signal from the stator on at least one phase of the stator and measuring an electrical signal from the position sensor; • the calculation of a first phase shift angle between the electrical signal of the position sensor and the electrical signal of the stator phase; • the rotation of a base of the measuring device around the axis of rotation of the rotor from the original orientation to a corrected orientation, the angle between the original orientation and the corrected orientation being equal to the calculated phase shift angle; • a second rotation of the rotor by the external shaft for a determined number of revolutions of the rotor; • the calculation of a second phase shift angle between the electrical signal of the position sensor and the electrical signal of the stator phase; • in the case where the second phase shift angle is outside an interval defined by a maximum threshold and a minimum threshold, an iteration of the previous steps, starting from the first rotation of the rotor, is carried out by defining the corrected orientation as the new original orientation; • fixing the measuring device on the stator by the fixing elements, according to the determined corrected orientation, in an operating position of the fixing elements.

[0011] Thanks to such a combination of characteristics, such a mechanical adjustment method makes it possible to obtain a higher precision of the angular position of a position sensor by means of a mechanical correction by iteration, less expensive than electronic and software alternatives. The angular orientation also has the advantage of being able to be adjusted from a single external equipment configured to fix the measuring device on the stator in addition to rotating the base of the measuring device.

[0012] The term "adjustment position" means a temporary position of the fixing elements in which the measuring device is held in position for the duration of the adjustment process, for example by applying a preload to the fixing elements. Rotation of the base of the device by external equipment is thus permitted and any other unwanted rotation is blocked.

[0013] The term "operating position" means a permanent position of the fixing elements in which the measuring device is held in position for operating phases of the rotating electrical machine, any rotation of the base of the device is thus blocked.

[0014] Advantageously, the maximum threshold is less than or equal to 2°, more preferably less than or equal to 1° and the minimum threshold is greater than -2°, more preferably greater than or equal to -1°, the maximum threshold being greater than the minimum threshold.

[0015] Advantageously, the electrical signal of the position sensor and the electrical signal of the stator phase are measured at each revolution of the rotor, an average electrical signal of the position sensor and an average electrical signal of said at least one phase of the stator, calculated from the successive measurements during each of the revolutions. In such a configuration, the precision and reliability of the phase shift angles obtained are reinforced, which improves the adjustment of the measuring device and, finally, the efficiency and future performance of the electrical machine.

[0016] Advantageously, the measurement of the electrical signal of the stator is carried out on three or six phases of the stator. Optionally, the measurement of the electrical signal of the stator is carried out on all of the phases of the stator. In such a configuration, the measuring device may comprise a plurality of sensors each facing a target fixed to the rotor, and a plurality of electrical signals of the stator are measured. In addition, an average phase shift angle can thus be calculated, which further increases the reliability and accuracy of the adjustment.

[0017] Advantageously, the number of revolutions of the rotor is greater than or equal to 2 revolutions, in particular greater than or equal to 5 revolutions. The higher the number of revolutions of the rotor, the greater the accuracy of the measurement of the electrical signals. In particular, with a satisfactory number of revolutions, the transient effects acting on all the electrical components of the measuring device and the electrical machine disappear, the measurements are then carried out under conditions corresponding to the conditions of the predominant operating phase of said electrical machine.

[0018] Advantageously, when the rotor is rotated, the outer shaft drives the rotor at a determined rotation speed, the rotation speed preferably being between 200 rpm and 1500 rpm.

[0019] Advantageously, in the adjustment position, an adjustment tightening torque is applied to the fixing elements. The adjustment tightening torque may be between 0.8 Nm and 1.2 Nm, in particular between 0.9 Nm and 1.1 Nm.

[0020] Advantageously, in the operating position, an operating tightening torque is applied to the fastening elements. The operating tightening torque may be greater than the adjustment torque, in particular 5 times greater, in particular 10 times greater. The operating tightening torque may be between 3 Nm and 4 Nm.

[0021] Advantageously, information on the value of the second phase shift angle is stored by the position sensor, said information being able to be stored physically and / or digitally. In such a configuration, the adjustment method only needs to be carried out once when the rotating electrical machine and the associated measuring device are put into service and the adjustment can be carried out again after a maintenance operation aimed at changing an element of the electrical circuit, for example an inverter connected to the phases of the rotating electrical machine. The method can thus for example comprise a step of engraving the value of the angle on the base of the measuring device or a step of printing a label of the value of the angle stuck on the sensor. In addition, the information can be stored in digital format on a storage means internal or external to the measuring device.

[0022] According to another aspect of the invention, it relates to a measuring device for implementing an adjustment method as described above, the measuring device comprising: • a position sensor for a rotating electrical machine, said rotating machine comprising a rotor and a stator; • a mobile base rotating between an original orientation and a corrected orientation in which the position sensor is housed; • fixing elements movable between an adjustment position and an operating position configured to fix the base to an axial end of the stator of the electric machine; the measuring device being characterized in that the base comprises a toothing configured to cooperate with a toothing of an external spindle to drive the position sensor and the base in rotation.

[0023] According to another aspect of the invention, it relates to a rotating electrical machine comprising a stator, a rotor and a measuring device as described above.

[0024] According to another aspect of the invention, it relates to a mobility device comprising an electric machine as described above. PRESENTATION OF THE FIGURES

[0025] The invention will be better understood on reading the following description, given solely by way of example, and referring to the appended drawings given by way of non-limiting examples, in which identical references are given to similar objects and in which:

[0026] [Fig.l] is a schematic representation of a rotating electrical machine comprising a stator, according to a first aspect of the invention;

[0027] [Fig.2] is a schematic representation of a position measuring device according to another aspect of the invention;

[0028] [Fig. 3] is a schematic representation, in axial section, of a measuring device base.

[0029] It should be noted that the figures set out the invention in detail to enable the invention to be implemented; although not limiting, said figures serve in particular to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0030] [Fig.l] is a schematic representation of a rotating electrical machine 2 comprising a stator 3 and a measuring device 1, according to one embodiment of the invention. The rotating electrical machine 2 in this example is an electric motor of an electric or hybrid motor vehicle. The electric motor may have a voltage of 48V and a power of 15kW, for example.

[0031] The invention also applies to other types of rotating electrical machine such as an alternator or an alternator-starter of a motor vehicle. The stator 3 comprises a winding. By winding is meant a coil or several coils based on electrically conductive copper wires. The rotating electrical machine 3 also comprises a rotor that can rotate relative to the stator 3 around an axis of rotation 100 inside the winding.

[0032] For the purposes of the invention, “axial” and “axially” refer to a direction parallel to the axis of rotation 100. The stator 3 further comprises a casing 18 surrounding the stator 3 and the rotor to protect them.

[0033] The position measuring device 1 comprises a position sensor 10 measuring the position of the rotor relative to the stator 3. The position measuring device 1 may comprise several position sensors 10 for measuring the position and speed of the rotor. The position sensor 10 may for example be a Hall effect sensor or an inductive type sensor, or even an optical sensor. The sensor 10 is connected to an electrical connector 24.

[0034] The position measuring device 1 is positioned in an axial end zone of the stator 3 so as to allow the position sensor 10 to detect a rotating mobile target connected to the rotor. The target of the rotor is for example a permanent magnet. The axial end zone corresponds to an area located between the rotor and the bearing and radially inside the winding of the stator 3.

[0035] The measuring device 1 comprises a housing 20 of curved shape with a curvature having as its axis of curvature the axis of rotation 100, as illustrated in [Fig. 2]. The housing 20 comprises a lower part 22 of smaller width, for example in the direction of the central axis 100. The position sensor 10 is housed in the lower part 22 of the housing 20.

[0036] The position measuring device 1 comprises a base 14 projecting axially relative to the housing 20. Preferably, the base 14 projects perpendicularly relative to the housing 20. The housing 20 is preferably formed from a polymer material, for example a plastic polymer.

[0037] The base 14 comprises a flange 26 extending perpendicularly to the axis of rotation 100. The flange 26 comprises several oblong holes 28 opening out configured to house fixing elements 12 making it possible to fix the base 14 to the stator 3. The fixing elements 12 are for example a screw and washer assembly, arranged so that a screw head rests on a washer and said washer rests on edges of the oblong holes 28, the screw extending through the oblong holes to cooperate with threads in the casing 18 of the stator 3.

[0038] The fastening elements 12 are thus movable between an adjustment position and an operating position. By "adjustment position" is meant a temporary position of the fastening elements 12, for example by applying a prestress to the fastening elements. Rotation of the base 14 of the measuring device 1 by external equipment is thus permitted and any other unwanted rotation is blocked. By "operating position" is meant a permanent position of the fastening elements 12 in which the measuring device 1 is held in position for operating phases of the rotating electrical machine 2, any rotation of the base 14 of the device being thus blocked. The flange 26 is preferably formed from a metal, for example stainless steel.

[0039] According to one embodiment, the flange 26, the base 14 and the housing 20 form a single composite part.

[0040] Each oblong hole 28 has an oblong and curved shape around the rotation axis 100 having as its center of curvature the rotation axis 100. The oblong holes 28 are sufficiently extended to allow a rotational movement to be applied to the position measuring device 1 to calibrate the position sensors with the rotor target. The oblong holes 28 extend over a length of at least 1 cm and preferably at least 2 cm.

[0041] The base 14 of the measuring device 1 comprises axially projecting teeth 16 configured to cooperate with teeth of an external spindle to drive the base 14 and the position sensor 10 in rotation about the axis. Preferably, the teeth of the teeth 16 have slopes, in particular slopes equal to 5°.

[0042] According to another aspect of the invention, it relates to a method for adjusting the measuring device 1 as described above. The remainder of the description focuses on detailing the steps of such a method.

[0043] The measuring device 1 is positioned opposite a target fixed to the rotor according to a given angular orientation of the base 14 of said measuring device 1 relative to the casing 18 of the stator 3 around the axis of rotation 100.

[0044] The measuring device 1 is fixed on the casing 18 of the stator 3 according to the angular orientation of the base defined in the previous step. The fixing elements 12 are then inserted into the flange 26 of the base 14 in their adjustment position. An adjustment tightening torque is applied, for example an adjustment tightening torque of between 0.9 Nm and 1.1 Nm.

[0045] The rotor is driven for a first rotation around the rotation axis 100 by an external shaft for a determined number of revolutions of the rotor. For example, the number of revolutions is greater than 10. In practice, the higher the number of revolutions, the better the precision of the adjustment method, ensuring the disappearance of the effects of the electrical and mechanical transient regime experienced by the rotating electrical machine 2.

[0046] An electrical signal of the stator 3 is measured on at least one phase of the stator 3 and an electrical signal is measured on each position sensor 10. In the case where the measuring device 1 comprises a plurality of position sensors 10, an electrical signal is measured for each position sensor 10 and for each of the phases of the stator 3. In addition, the measurement of the electrical signals of the phases and of the position sensors 10 is carried out for each revolution of the rotor on itself, and an average electrical phase signal and an average electrical sensor signal are then determined. Such signals have the advantage of being more precise than an instantaneous measurement.

[0047] A first phase shift angle is then calculated between the electrical signal from position sensors 10 and the electrical phase signal of the stator, an operation known to those skilled in the art as the determination of a time delay or a time advance of an electrical signal relative to another electrical signal.

[0048] The rotation of the rotor is stopped. An angular rotation of the base 14 of the measuring device 1 is then carried out by an external spindle cooperating with the teeth 16 of the base 14, so that the measuring device 1 pivots from the original orientation to a corrected orientation, the angle between the two orientations corresponding to the phase shift angle measured between the electrical phase signal and the electrical signal of the position sensor 10

[0049] The rotor is driven for a second rotation around the rotation axis 100 by the outer shaft for a determined number of revolutions of the rotor. For example, the number of revolutions is greater than 10. In practice, the higher the number of revolutions, the better the precision of the adjustment method, ensuring the disappearance of the effects of the electrical and mechanical transient regime experienced by the rotating electrical machine 2.

[0050] A second phase shift angle is then calculated between the electrical signal from position sensors 10 and the electrical phase signal from stator 3. The rotation of the rotor is stopped.

[0051] In the case where the second phase shift angle is within an interval defined by a maximum threshold and a minimum threshold, the measuring device 1 is then fixed to the casing 18 of the stator 3 in an operating position of the fixing elements 12. An operating tightening torque is applied, for example an operating tightening torque of between 3 Nm and 4 Nm.

[0052] In the case where the second phase shift angle is outside the interval formed by a maximum threshold and a minimum threshold, an iteration of the previous steps, starting from the first rotation of the rotor, is carried out by defining the corrected orientation as the new original orientation. As long as the second phase shift angle is outside the interval, the adjustment method continues iteratively.

[0053] Such a mechanical adjustment method makes it possible to obtain a higher precision of the angular position of the position sensor 10 by means of a mechanical correction by iteration, less expensive than electronic and software alternatives. In addition, the external spindle allowing the rotation of the base 14 around the axis of rotation 100 is shared with fixing tools configured to apply a tightening torque to the fixing elements 12. In such a configuration, the fixing operation, in particular the fixing operation in the operating position of the fixing elements is directly subsequent to the step of rotating the base 14. The time taken to carry out the operation is thus improved, and it is ensured that the measuring device 1 is fixed in a durable manner with an angular orientation consistent with the last measured phase shift angle.

[0054] The maximum threshold is for example less than or equal to 2°, more preferably less than or equal to 1° and the minimum threshold is for example greater than -2°, more preferably greater than or equal to -1°, the maximum threshold being greater than the minimum threshold.

[0055] Information on the value of the second phase shift angle is stored by the position sensor 10, said information being able to be stored materially and / or digitally.

[0056] In the case where the value is stored materially, the adjustment method comprises for example a step of engraving the value of the second phase shift angle, for example an engraving on the housing 20 of the position sensor 10. Alternatively, a label comprising the value of the second angle can be stuck on the housing 20.

[0057] In the case where the value is stored digitally, the measuring device may comprise an internal storage means. Alternatively, the storage may be done remotely external to the measuring device 1.

[0058] In such a configuration, the adjustment method only needs to be carried out once when commissioning the rotating electrical machine 2 and the associated measuring device 2 and the adjustment can be carried out again after a maintenance operation aimed at changing an element of the electrical circuit, for example an inverter connected to the phases of the rotating electrical machine. 2

[0059] It will also be noted that the invention is not limited to the embodiment described above. It will indeed appear to those skilled in the art that various modifications can be made to the embodiment described above, in light of the teaching which has just been disclosed to them.

[0060] In the detailed presentation of the invention which is made above, the terms used must not be interpreted as limiting the invention to the embodiment set out in the present description, but must be interpreted to include all equivalents whose prediction is within the reach of those skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

1. Claims Method for adjusting a measuring device (1) comprising at least one position sensor (10) for a rotating electrical machine (2), comprising a rotor and a stator (3), the method comprising: • the positioning of the measuring device (1) on the stator (3), opposite a target fixed to the rotor defining an original orientation; • fixing the measuring device (1) on the stator by fixing elements (12) of the measuring device (1), in an adjustment position of said fixing elements (12); • a first rotation of the rotor around an axis of rotation (100) of the rotor by a shaft external to the electric machine (2) for a determined number of revolutions of the rotor; • measuring an electrical signal from the stator (3) on at least one phase of the stator (3) and measuring an electrical signal from the position sensor (10); • the calculation of a first phase shift angle between the electrical signal of the position sensor (10) and the electrical signal of the stator phase (3); • the rotation of a base (14) of the measuring device (1) around the axis of rotation (100) of the rotor from the original orientation to a corrected orientation, the angle between the original orientation and the corrected orientation being equal to the calculated phase shift angle; • a second rotation of the rotor by the external shaft for a determined number of rotor revolutions; • calculating a second phase shift angle between the electrical signal of the position sensor (10) and the electrical signal of the stator phase; • in the case where the second phase shift angle is outside an interval defined by a maximum threshold and a minimum threshold, an iteration of the previous steps, starting from the first rotation of the rotor, is carried out by defining the corrected orientation as the new original orientation; • fixing the measuring device (1) on the stator by the fixing elements (12), according to the corrected orientation de- completed, in a position of operation of the fixing elements (12).

2. Adjustment method according to claim 1, characterized in that the maximum threshold is less than or equal to 2°, more preferably less than or equal to 1° and the minimum threshold is greater than -2°, more preferably greater than or equal to -1°, the maximum threshold being greater than the minimum threshold.

3. Adjustment method according to the preceding claim, characterized in that the electrical signal of the position sensor (10) and the electrical signal of the phase of the stator (3) are measured at each revolution of the rotor, an average electrical signal of the position sensor (10) and an average electrical signal of said at least one phase of the stator (3), calculated from the successive measurements during each of the revolutions.

4. Adjustment method according to any one of the preceding claims, characterized in that the measurement of the electrical signal of the stator (3) is carried out on three or six phases of the stator (3).

5. Adjustment method according to any one of the preceding claims, characterized in that the number of revolutions of the rotor is greater than or equal to 2 revolutions.

6. Adjustment method according to any one of the preceding claims, characterized in that when the rotor is rotated, the outer shaft drives the rotor at a determined rotation speed, the rotation speed preferably being between 200 rpm and 1500 rpm.

7. Adjustment method according to any one of the preceding claims, characterized in that in the adjustment position, an adjustment tightening torque, in particular between 0.8 Nm and 1.2 Nm, in particular between 0.9 Nm and 1.1 Nm is applied to the fastening elements (12) and, in the operating position, an operating tightening torque, in particular between 3 Nm and 4 Nm is applied to the fastening elements (12).

8. Adjustment method according to any one of the dependent claims, characterized in that information on the value of the second phase shift angle is stored by the position sensor (10), said information being able to be stored materially and / or digitally.

9. Measuring device for implementing an adjustment method according to any one of claims 1 to 8, the measuring device comprising: • a position sensor (10) for a rotating electrical machine (2), said rotating machine (2) comprising a rotor and a stator (3); • a base (14) movable in rotation between an original orientation and a corrected orientation in which the position sensor (10) is housed; • fixing elements (12) movable between an adjustment position and an operating position configured to fix the base (14) to an axial end of the stator (3) of the electric machine (2); the measuring device (1) being characterized in that the base (14) comprises a toothing (16) configured to cooperate with a toothing of an external spindle to drive the position sensor (10) and the base (14) in rotation.

10. A rotating electrical machine comprising a stator (3), a rotor and a measuring device (1) according to claim 9.

11. Mobility device, characterized in that it comprises an electric machine (2) according to claim 10.

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