Synchronous machine provided with an angular position sensor

Abstract

The invention relates to a synchronous machine (1) including a stator (2) and a rotor (3). Said machine is provided with at least one sensor (1a) of the angular position of the rotor (3) and is characterized in that the stator (2) includes a winding provided such as to be supplied with polyphase current by an electronic power device. The rotor (3), which includes permanent magnets (4), is provided such as to rotate about the stator (2). The angular position sensor (1a) extends away from the rotor (3) and is in alignment with the latter at the permanent magnets (4). The angular position sensor (1a) includes at least two sensors (6) for measuring magnetic induction and are provided for detecting variation in the axial magnetic field of the rotor (3) in the form of voltage, and the angular position sensor (1a) moreover includes at least one electronic unit provided for receiving the voltages of the magnetic induction measurement sensors (6) such as to absolutely deduce therefrom the angular position of the rotor (3) and send corresponding information, in real time, to the electronic power device.

Claims

1. A synchronous machine comprising a stator and a rotor, the machine being equipped with at least one angular position sensor module of the rotor, wherein: the stator has a winding designed to be supplied with multi-phase AC current by an electronic power device, the rotor comprises components that generate magnetic induction and designed to move in rotation when power is supplied to the stator, the angular position sensor module comprises at least one pair of two magnetic induction measurement sensors to detect the variation of the axial magnetic field generated by the components that generate magnetic induction while supplying a voltage, the said sensors of the module or of each module being at an angular deviation of 90 electrical degrees, the magnetic induction measurement sensors, integral with the stator, extend at an axial end of rotor, opposite and immediately next to the axial edges of the components that generate the magnetic induction, wherein the magnetic induction measurement sensors are attached and set out on at least one removable support of the stator so as to extend along a line whose curve substantially matches the curve of the succession of axial edges of the components that generate the magnetic induction, and the angular position sensor module comprising at least one electronic unit to receive output voltages supplied by the magnetic induction measurement sensors, to determine an absolute angular position of the rotor and to transmit the determined absolute angular position to the electronic power device in real time.

2. The synchronous machine according to claim 1, wherein the rotor extends around the stator.

3. The synchronous machine according to claim 1, comprising at the least two angular position sensor modules.

4. The synchronous machine according to claim 1 wherein the at least one removable support comprises two removable supports each provided with five magnetic induction measurement sensors, including the at least one pair of two magnetic induction measurement sensors.

5. The synchronous machine according to claim 1 wherein the removable support comprises at least one electronic circuit of the electronic unit.

6. The synchronous machine according to claim 1, wherein the removable support comprises a temperature sensor.

7. The synchronous machine according to claim 1, wherein the magnetic induction measurement sensors comprise Hall effect sensors.

8. The synchronous machine according to claim 1, wherein the magnetic induction measurement sensors comprise magnetoresistance sensors.

9. The synchronous machine according to claim 1, wherein the electronic power device includes a converter configured to drive the said synchronous machine by pulse width modulation.

10. The synchronous machine according to claim 1, wherein the components that generate the magnetic induction comprise permanent magnets.

11. The synchronous machine according to claim 1, wherein the synchronous machine is implemented as a wheel-motor of a vehicle.

12. The synchronous machine according to claim 1, wherein the at least one pair of two magnetic induction measurement sensors comprises a first pair of magnetic induction measurement sensors and a second pair of magnetic induction measurement sensors, wherein a magnetic induction measurement sensor of the first pair is at an angular deviation of 90 electrical degrees to a nearby magnetic induction measurement sensor of the first pair, and wherein a magnetic induction measurement sensor of the second pair is at an angular deviation of 90 electrical degrees to a nearby magnetic induction measurement sensor of the first pair.

Description

(1) Other characteristics and advantages of the invention will also appear in the drawings provided as non-limiting illustrations and in which:

(2) FIG. 1 illustrates an example of the embodiment of a synchronous machine conforming to the invention incorporating an angular position sensor on part of a stator;

(3) FIG. 2 shows a sectional detail view of FIG. 1;

(4) FIG. 3 illustrates an example of the embodiment of a removable support for the angular position sensor module, shown front-on, designed for insertion into a synchronous machine conforming to the invention;

(5) FIG. 4 is a block diagram of the electronic means required for the operation of the angular position sensor module la of the synchronous machine 1 conforming to the invention. The latter therefore comprises the wound stator 2 (comprising the electric windings 17) and the rotor 3 comprising the permanent magnets 4.

(6) FIG. 5 illustrates, by means of a functional diagram, an example of the vectorial control system of a permanent magnet and sinusoidal electromotive force synchronous machine, conforming to the invention.

(7) FIG. 6 is an example of the signals measured by magnetic induction sensors with a synchronous machine conforming to the invention;

(8) FIG. 7 is an example of the corrected signal obtained by an angular position sensor module comprising two sensors, producing standardized axial field values according to time; and

(9) FIG. 8 represents the angular position calculated from the axial field measured in a synchronous machine with two poles conforming to the invention.

DETAILED DESCRIPTION OF FIGURES

(10) FIG. 1 illustrates an example of the embodiment of a synchronous machine 1 comprising an angular position sensor mounted to a stator 2 illustrated schematically in FIG. 4. FIG. 1 shows part of the end 2a, for instance, in the form of a flange mechanically integral with the stator 2.

(11) The synchronous machine 1 also includes a rotor 3 provided with permanent magnets 4.

(12) The end part 2a covers at least partially, and without contact, an axial end 3a of the rotor 3. An example of the set-up between the axial end 3a and the end part 2a is illustrated in greater detail in FIG. 2.

(13) The stator 2 comprises a winding, not shown, designed to be supplied with multiphase current by an electronic power device also known as a converter or inverter. Advantageously, the latter is supplied with voltage and current.

(14) The rotor 3 advantageously has a substantially cylindrical shape 3b, the inner face of which is covered with permanent magnets 4. Rotor 3 is designed to rotate about the part of the stator 2 extending in the free space contained inside the said rotor 3. The permanent magnets 4 are, for instance, stacked in an axial direction of the axial grooves made in the inside face of cylinder 3b. The assembly and attachment of the permanent magnets 4 to the inside face of the rotor 3 is done in a known manner.

(15) For instance, the permanent magnets 4 are inserted by being slid into the axial grooves where they are held radially by the matching shapes of the said grooves and the said permanent magnets 4.

(16) Axially, the permanent magnets 4 are locked in each groove by means of a retaining part 5 of an anti-magnetic material, illustrated in greater detail in the FIG. 2.

(17) According to an example of a non-limiting embodiment, the retaining part 5 forms a stop 5a preventing the axial movement of the permanent magnets 4 engaged in the corresponding groove. The sizes and shapes of the retaining part 5 are chosen so as not to impede access to an area located opposite at least one part of axial edge 4a of the last permanent magnet 4 engaged in each groove. Other known technical retaining solutions can also be considered.

(18) The axial end 3a of the cylinder 3b, which does not have permanent magnets 4, advantageously comprises for the purpose, a slightly hollowed-out shape in a radial direction. This shape makes it possible to limit the dimensions resulting from the attachment of the retaining part 5. Advantageously, a retaining part 5 is attached to the cylinder 3b, at the end of each groove by a screw 5b, thus actively locking all the rows of permanent magnets 4.

(19) The synchronous machine 1 conforming to the invention also comprises an angular position sensor module 1a for rotor 3. In particular, the angular position sensor module comprises one or several pairs of magnetic induction measuring sensors 6. The latter are designed to detect the variation of the axial magnetic field generated by the permanent magnets 4. This variation of the axial magnetic field is detected and converted into voltage, supplied by the magnetic induction measurement sensors 6.

(20) The angular deviation between the sensors 6 of each pair is 90 electrical degrees. For instance, 90 electrical degrees represent 4.5 mechanical degrees for a motor with 20 pairs of poles.

(21) The angular position sensor la also comprises at least one electronic unit designed to receive the induction voltages from the magnetic induction measurement sensors 6 and to deduct from them the angular position of rotor 3. This determination is carried out in an absolute manner.

(22) The electronic unit also allows real-time transmission of information relative to the angular position of rotor 3 to the electronic power device.

(23) The magnetic induction measurement sensors 6 are mechanically integral with the end part 2a and extend at an axial end of rotor 3, opposite and immediately next to the axial edges 4a of the last permanent magnets 4 engaged in the grooves. When rotor 3 rotates, each axial edge 4a therefore passes in front of magnetic induction measurement sensors 6.

(24) Advantageously, the magnetic measurement sensors 6 are attached to a removable support 7.

(25) For this purpose, the removable support 7 has an axial support part 7a and a support end part 7b. The end part of the support 7b extends substantially transversely to the part of the axial support 7a. The magnetic induction measurement sensors 6 are arranged on an outer face 7c of the free end of the axial support part 7a.

(26) The removable support 7 preferably forms a curve substantially matching the curve of the rotor 3. The magnetic induction measurement sensors 6 are advantageously attached and set out on an outer face 7c, on a line the curve of which substantially matches the curve of the succession of axial edges 4a of the permanent magnets 4. The removable support 7 is, for instance, inserted into a slot 8 made in the end part 2a. Naturally, the slot 8 has a curve which is identical or similar to the one in the part of the axial support 7a.

(27) Once the removable support 7 is provided with the magnetic induction measurement sensors 6, it is axially inserted into the slot 8 until it abuts on the end part of support 7b, on the outer face of end part 2a. The dimensions of the removable support 7, and in particular the axial length of the axial support part 7a are chosen so that the magnetic induction measurement sensors 6 extend to a distance e from the axial edges 4a. The distance e is included for instance between 1.5 and 2.5 millimeters and preferably equal to 2 millimeters.

(28) All types of attaching means, not shown, can also be used to make the end of support 7b integral with the end part 2a.

(29) In one example of the embodiment, the synchronous machine 1 comprises at least two magnetic induction measurement sensors 6 arranged on a removable support 7, and placed at 90 electrical degrees from one another.

(30) In another example of the embodiment, the synchronous machine 1 conforming to the invention, illustrated in FIG. 1, comprises two removable supports 7 each of which is provided with, for instance, at least two magnetic induction measurement sensors 6.

(31) FIG. 3 is a head-on illustration of an example of the embodiment of a removable support 7 comprising five magnetic induction measurement sensors 6.

(32) Accordingly, according to an example of the embodiment in FIG. 3, the synchronous machine 1 comprises two removable supports 7 each comprising five magnetic induction measurement sensors 6.

(33) Advantageously, the outer face 7c of the axial support part 7a is provided with a temperature sensor 9. The latter is used for measuring the ambient temperature of the synchronous machine 1 in order to adjust its control because the induction depends on the temperature.

(34) In a preferential example of the embodiment, the removal support 7 comprises at least one electronic circuit of the electronic unit or one part of the electronic circuit of the said electronic unit.

(35) As an example, the electronic power device is a converter driving the synchronous machine 1 by pulse width modulation.

(36) The magnetic induction measurement sensors 6 are preferably Hall effect sensors. In another example of the embodiment of synchronous machine 1, the magnetic induction measurement sensors 6 consist of AMR/GMR sensors known as magnetoresistance sensors.

(37) While the Hall effect sensors can be used for measuring the continuous component of the magnetic field, magnetoresistance sensors operate on the basis of the electrical resistance variation of a material depending on the direction of the magnetic field applied to it. These sensors are known in their own right and accordingly are not described any further.

(38) By using Hall effect sensors or magnetoresistance sensors, the operation of calibrating the angular position sensor 1 a is no longer necessary. Indeed, these sensors measure the spatial distribution of the magnetic field generated by the permanent magnets 4 even when the synchronous machine 1 is at a stop. This dispenses with the need for any calibration operation on the commissioning of the synchronous machine 1 or after a maintenance operation on the said synchronous machine 1. This represents an outstanding advantage for the synchronous machine 1 conforming to the invention.

(39) FIG. 4 is a block diagram of the electronic means required for the operation of the angular position sensor module la of the synchronous machine 1 conforming to the invention. The latter therefore comprises the wound stator 2 and the rotor 3 comprising the permanent magnets 4.

(40) The angular position sensor la therefore comprises functional means which comprise induction measurement sensors 6, associated with the electronic unit for the acquisition of a signal and for calculating the positioning angle of the rotor 3.

(41) The functional means comprise, for instance, two magnetic induction measuring sensors 6, mounted in to be fixed, without contact, and facing the permanent magnets 4. Information coming from these induction measuring sensors 6 is then amplified and filtered respectively by amplification means 10 and filtering means 11, before being acquired by a computer 12. This computer 12 of the electronic unit therefore determines a rotor angle (angular position of the rotor) from the information from the induction measuring sensors 6 and in real time transmits the rotor angle to a vectorial control system 13 which controls a converter 14.

(42) The rotor angle is transmitted to the vectorial control system 13 via a field BUS type protocol such as SSI, PROFIBUS or another. In addition, the sign of the rotor angle determined by the computer 12 defines the direction of rotation of the synchronous machine 1.

(43) FIG. 5, by means of a functional diagram, illustrates the vectorial control system 13 of a synchronous machine 1 with permanent magnets 4 and sinusoidal electromotive force. In this example of a vectorial control system, the synchronous machine 1 comprises the converter 14 supplied with electric voltage.

(44) The vectorial control system 13 controls the converter 14 by means of pulse width modulation PWM to generate a medium power supply voltage on each of the phases P.sub.1, P.sub.2, P.sub.3 of synchronous machine 1 and thereby, a determined current in each of the said phases P.sub.1, P.sub.2, P.sub.3. The converter 14 therefore transforms the voltage supplied by a DC voltage source U into a three phase voltage supplying the synchronous machine 1. The latter operates, for instance, by traction and alternately as a three phase voltage generator when a vehicle is in the braking phase.

(45) The vectorial control system 13 comprises a converter control unit 14, current sensors 15, a voltage sensor 16 and the angular position sensor 1a of the synchronous machine 1.

(46) The vectorial control system 13 receives, for instance, the torque setpoint C. From the information derived from the current sensors 15, the angular position sensor module la and from the setpoint C, the converter control unit 14 calculates the voltage vector to be applied to the said converter 14 so that the synchronous machine 1 reaches the torque setpoint C. The vectorial control system 13, in particular the permanent magnet 4 and sinusoidal electromotive force synchronous machine 1, is known in its own right and will therefore not be described any further here.

(47) The synchronous machine 1 has the outstanding advantage of comprising an angular position sensor 1 a capable of directly measuring the magnetic field produced by the permanent magnets 4 and thereby knowing how the magnetic field changes in the course of time. In this way, any deterioration of the performance of permanent magnets 4 can be detected, and thereby, so can the performance of the synchronous machine 1 conforming to the invention.

(48) Furthermore, angular position sensor la of synchronous machine 1 is capable of detecting an abrupt increase in the induced magnetic field, resulting from short-circuiting between phases.

(49) FIG. 6 is an example of the signals measured by magnetic induction sensors 6 mutually arranged at 90 electrical degrees from one another. An arrangement like this corresponds to a mechanical angle of 4.5 for machines comprising 20 pairs of poles. A module like this is capable of measuring the axial field produced by the magnets. The signals A and B, respectively depicted as fine and broad lines, are supplied by two respective sensors 6 in the form of an electric voltage V and consist of sinusoidal signals deformed by the presence of order 3 harmonics in the axial field. The signals A and B are signals that are measured and filtered in a known way.

(50) To correct any non-linearity in the signal, it is possible to use an adaptive filtering device, known in its own right, or to use a correction device based on the use of several angular position sensor modules la having any angular deviation between the modules

(51) Following this correction, the measured, filtered and corrected values have sinusoidal shapes Al and Bi from which the angular position of rotor 3 can be determined. FIG. 7 is an example of the corrected signals A.sub.1 and B.sub.1, obtained by an angular position sensor module comprising two sensors, producing standardized axial field values according to time.

(52) As an example, FIG. 8 represents the absolutes angular position , known as the angle, calculated from the axial field measured in a synchronous machine 1 with two poles conforming to the invention.

(53) The determination of the angular position is made by the electronic unit according to the calculations specified below while considering that y correspondence to the values illustrated by the curve of signal B.sub.1 and that x correspondence to the values illustrated by the curve of signal A.sub.1. Accordingly:
if x>0 and y>0; =atan(y/x)
if x=0 and y>0; =/2
if x<0 and y0; =+atan(y/x)
if x<0 and y<0; =+atan(y/x)
if x=0 and y<0; =3/2
if x>0 and y<0; =atan(y/x)+2

(54) Permanent magnet 4 and sinusoidal electric force synchronous machine 1, conforming to the invention, advantageously form a wheel motor.

(55) The synchronous machine conforming to the invention can also be used as a winch motor or an elevator motor.

(56) It is obvious that this description is not confined to the examples explicitly described but also extends to other embodiments and/or implementation methods.

(57) Accordingly, a described characteristic may be replaced by an equivalent technical characteristic without moving out of the framework of the invention.