Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
  • H02K7/08—Structural association with bearings
  • H02K7/09—Structural association with bearings with magnetic bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
  • F16C32/0406—Magnetic bearings
  • F16C32/044—Active magnetic bearings
  • F16C32/0474—Active magnetic bearings for rotary movement
  • F16C32/0493—Active magnetic bearings for rotary movement integrated in an electrodynamic machine, e.g. self-bearing motor
  • F16C32/0497—Active magnetic bearings for rotary movement integrated in an electrodynamic machine, e.g. self-bearing motor generating torque and radial force

Definitions

• the present invention relates to an actuator comprising two magnetic bearing motors.
• a bearing motor which forms a dual function actuator that integrates the windings of the centralizer and the motor into a single actuator.
• Such an actuator makes it possible to reduce the number of elements in the rotating system and to maintain independent control of the torque and radial forces. Configurations with the windings of the bearing and the motor in common on a single device also exist. Bearing motor embodiments incorporate certain defects such as a magnetic circuit containing iron, which is responsible for additional loss of eddy currents at high frequencies. Bearing motors also require a power electronics rich in communication cells as well as complex control processes, which hinders their industrialization.
• a passive magnetic bearing uses permanent magnets while an active magnetic bearing uses a current coil around a magnetic circuit, said coil being used to create attractive forces in its environment.
• the active bearings are slaved to obtain an effective support of the shaft, this by a control electronics often sophisticated and expensive.
• Another source of loss is due to the presence of iron in the components of the actuator or the part that it drives.
• the presence of iron in said elements is responsible for additional loss by eddy currents, especially at high frequencies.
• EP-A-2 107 668 discloses a rotating electrical machine, in which a magnetic support force can be realized even when the rotor length is important.
• the rotating electrical machine has a rotor mounted on the main shaft and a stator surrounding the rotor.
• the rotor has a first section producing a rotational torque in the circumferential direction of the rotor shaft or torque and the bearing force and a second section creating an outward bearing force in the radial direction of the rotor. the rotor shaft.
• WO-A-02/40884 discloses a rotating machine with a rotary shaft supported by first and second radial magnetic bearings driven by a current control device.
• the rotary shaft is equipped with an axial thrust device comprising a rotor formed of a solid disc. This document describes no bearing motor but only radial magnetic bearings and has the same disadvantages as previously mentioned.
• the object of the present invention is to provide an actuator for reducing all the friction that it undergoes during its operation as well as to rotate its motor shaft by eliminating any parasitic movements that may be caused during its rotation.
• the present invention relates to an actuator with at least one magnetic bearing motor, said at least one motor comprising a rotor and a stator, the rotor being magnetically suspended relative to the stator, characterized in that it comprises two bearing motors magnetic arranged in the extension of one another, the two bearing motors being angularly offset relative to each other and in that between the two bearing motors is interposed an active or passive stop, said stop acting on the rotor and stator portions of each bearing motor, a housing being provided on the actuator between the first and second bearing motors for receiving the stop.
• Such an actuator with two bearing motors makes it possible to guarantee a constant torque for the rotation shaft, the torque of one of the bearing motors being zero in certain angular positions and being compensated for by the torque of the other bearing motor.
• the two bearing motors are offset by a mechanical angle of
• each bearing motor is formed of magnets symmetrically distributed around the stator portion of said bearing motor.
• the magnets are distributed to form a Halbach structure for creating a magnetic flux of an asymmetrical profile, said flux being amplified on one side of the structure being reduced or canceled on the other side.
• the magnets are based on lanthanides, organometallic magnets or organic magnets.
• stator and the rotor are made of composite or ceramic material.
• each bearing motor is formed of a substantially cylindrical core having grooves for the passage of at least one coil between two consecutive grooves.
• the three groups of coils are mounted in a star, the sum of the three currents for each bearing motor being zero.
• the actuator comprises means for controlling and controlling the parameters of its positioning by variation of the currents transmitted to said at least one coil, detection means in the form of at least one inductive sensor being provided on said actuator, the control means being active on the intensity of the currents transmitted to the coils of each bearing motor.
• the invention also relates to a method for controlling such an actuator, comprising a step of varying currents transmitted to said at least one stator coil of the actuator, said step being made as a function of the position and the torque of the actuator. actuator.
• said at least one coil of each bearing motor is powered by at least one current, the intensity of the current of the second bearing motor may or may not be different from the intensity of the current of the first bearing motor.
• each bearing motor is powered by at least three currents, each current supplying a respective group of coils, the three currents of the first bearing motor being different or different from the three currents of the second bearing motor.
• FIG. 1 represents a perspective view of a driven element about an axis with mention of the various degrees of freedom
• FIG. 2 represents a perspective view of an actuator composed of two bearing motors according to the present invention
• FIG. 3a shows a side view of the stator for an actuator according to the present invention, this stator being formed of two stator parts each of which corresponds to a bearing motor,
• FIG. 3b represents a longitudinal sectional view of the stator of FIG. 3a
• FIG. 3c represents a perspective view of the stator of FIG.
• FIG. 3d represents a developed view of a winding on the stator of FIG. 3a
• FIG. 4 represents a sectional view along A-A of the first bearing motor of the actuator according to the present invention
• FIG. 5 represents a sectional view along B-B of the second bearing motor of the actuator according to the present invention
• FIG. 6 shows a sectional view along A-A or B-B of a bearing motor of the actuator according to another embodiment of the present invention, the rotor magnets being in this figure placed in a Halbach arrangement,
• FIG. 7 represents a perspective view of a magnetic stop that can be interposed between the two bearing motors of the actuator according to the invention
• FIG. 8 represents an axial sectional view of the abutment of FIG. 7,
• FIGS. 9a, 9b and 9c show the force curves respectively along the X, Y and Z axes indicated in FIG.
• FIG. 1 shows a rotating element V and its shaft A, the rotating element being able to be a flywheel. In this figure, it is indicated the possible degrees of freedom of the rotating element V.
• this rotating element V Assuming that this rotating element V is completely free, its movement in space can be described by the combination of three translations and three rotations with respect to an orthonormal coordinate system which is shown with an axis Z extending along the axis of the rotation shaft A of the element V, an axis Y contained in the plane of the element V, the axis X being perpendicular to the first two axes Z and Y.
• the three degrees of freedom in rotation are respectively the rotation around the Y axis, the rotation ⁇ about the X axis and the rotation ⁇ about the Z axis.
• the rotation ⁇ In the case of a flywheel V of inertia intended to rotate around the Z axis, only the rotation ⁇ must be free, the other rotations being considered parasitic rotations.
• an actuator having two bearing motors angularly offset relative to each other, said bearing motors to be described later more precisely.
• angular offset of the two bearing motors relative to each other is understood an offset relative to the poles of the bearing motors relative to each other.
• Both bearing motors can be similar as of different design.
• the use of two bearing motors offset angularly relative to each other makes it possible to transmit a driving torque by action by rotation ⁇ about the Z axis but also to exert radial forces to control the forces R1 and R2. as well as the rotations a and ⁇ .
• the degree of freedom in translation along the Z axis is maintained by an advantageously passive magnetic stop. This concerns friction losses that the present invention wishes to reduce.
• the present invention provides for the actuator and the associated element to be made of nonferrous materials. This applies for example particularly to the magnets of the parts rotor and the stator parts of the two-motor actuator bearings.
• the actuator according to the invention combines the characteristics of a permanent magnet synchronous electric machine with magnetic rolling functions.
• the actuator is composed of two bearings motor 1 and 1 bis angularly offset. This makes it possible to guarantee a constant torque for the rotation shaft, the torque of one of the bearing motors 1 or 1bis being able to be zero in certain angular positions and being compensated for by the torque of the other bearing motor 1 bis or 1.
• two bearing motors 1 and 1 bis forming part of the actuator may be synchronous machines with permanent magnets in the rotor part.
• the bearing motors 1 and 1a are composed of six poles and three coils in the example below, but other structures are possible for controlling several axes, such as, for example, the four-stage motor. poles and coils.
• Each bearing motor 1 and 1 bis has, first of all, an external rotor with permanent magnets 3 and 3bis polarized and alternating.
• the arrangement of the polarized and alternating permanent magnets 3 and 3bis can be done either conventionally or by a Halbach structure. It is also possible to have an inner rotor surrounded by a stator.
• the arrangement of the magnets 3 and 3bis according to such a structure makes it possible to amplify the magnetic field on one side of the magnets 3 and 3bis while the magnetic field is canceled on the other side of the magnets 3 and 3bis.
• the arrows in the magnets 3, 3bis indicate the direction of the magnetic field.
• the permanent magnets 3 and 3bis are advantageously directly fixed on the rotating portion, which makes it possible to suppress the coupling of the rotor and the magnets 3 and 3bis.
• the inner stator carries coils 4.
• the coils 4 may advantageously be made of copper or aluminum.
• the stator is formed of a core 5 corresponding to the stator part 4 of the first bearing motor 1 and of a core 5a corresponding to the stator part 4a of the second motor. bearing.
• the cores 5, 5a are of substantially cylindrical shape and between the cores 5 and 5a is disposed a housing 10 for a magnetic stop, which will be described later.
• the stator shown in Figures 3a to 3c also comprises a receiving cavity 12 for an inductive sensor, said inductive sensor delivering a signal for controlling the position of the shaft carrying the actuator.
• Each core 5, 5bis has grooves 11, preferably longitudinal, advantageously six grooves 1 1 for winding coils on the peripheral portion of the core 5, 5a delimited by two adjacent grooves 1 1.
• stator part of the first bearing motor 1 and the stator part of the second bearing motor 1a are angularly offset with respect to each other, the grooves 11 of the first stator being angularly offset by relative to the grooves 1 1 of the second stator.
• FIG. 3d a winding is shown in developed and connecting two coils 41 between a groove 11.
• This winding can advantageously form an X between the two adjacent coils 41 of a stator.
• the coils 41 to 46 as well as 41 bis to 46 bis which will be shown in FIGS. 4 and 5.
• the stator part which is inside each bearing motor 1, 1 bis is composed of six coils 41 to 46, 41 bis to 46 bis on the core 5, 5 bis at low permeability, advantageously around periphery portions of the core 5, 5a delimited by two adjacent grooves 1, as shown in FIG. 3d.
• the core 5, 5bis does not contain iron.
• the winding of a phase is composed of two adjacent coils, connected by a circuit 6 or 6bis, only one of which is referenced in FIG. 4 or 5.
• Such an assembly contributes to the generation of a driving torque and a force radial on the rotor.
• the three coils 41 to 46, 41 bis to 46 bis are star-coupled and fed by three currents it, i2, i3 or il bis, i2bis, i3bis whose sum is zero for each of the bearing motors 1 or 1 bis.
• Figure 6 illustrates an embodiment of a bearing motor other than that shown in Figures 4 and 5.
• the magnets 3 are arranged in a Halbach structure. Such a structure increases the magnetic field of one side of the bearing motor while it decreases or cancels the other side.
• the Halbach structure comprises twelve magnets 3 forming the rotor part of a bearing motor with arrows symbolizing the direction of the magnetic field.
• the stator portion of the bearing motor remains essentially unchanged with respect to FIGS. 4 and 5.
• it is possible to use a Halbach structure for each bearing motor provided on the actuator which presents the advantage of allowing a better flow concentration and directly increases the performance of the actuator, the two bearing motors having an angular offset existing between them.
• the bearing motor structure 1 or 1 bis allows independent control and uncoupled three degrees of freedom X, Y and Z using a digital control of the three currents M, i2, i3 or i1bis, i2bis, i3bis as a function of position and torque.
• the electronic control of the actuator comprises means for controlling and controlling the positioning parameters of its shaft by varying the currents transmitted to said at least one coil, in the figures three groups of coils by bearing motor.
• This electronic control also comprises detection means, for example in the form of at least one inductive sensor, provided on the actuator previously described.
• the detection means monitor the position of the rotor of the actuator relative to its stator and the control means are active on the intensity of the currents transmitted to the coils of each bearing motor in order to bring the rotor back to its working position. predetermined.
• the rotor thus remains levitated with respect to the stator while being maintained at a very short distance from the stator, this in a safe manner.
• the actuator requires only three inverter arms to power the coils 41 to 46, 41 bis to 46 bis by non-sinusoidal currents.
• the numerical control of the three switching cells of the inverter makes it possible to generate constant forces independent of the angle of rotation while the torque is zero at certain angular positions. Guaranteeing a constant torque is therefore only possible by combining two bearings 1 or 1a motors staggered angularly as proposed by the present invention.
• the actuator is composed of two bearing motors 1, 1 bis angularly offset by 90 ° electrical or an angle of 22.5 ° mechanical for a six-pole motor.
• the two associated bearing motors 1, 1 bis make it possible to control the two additional degrees of freedom in rotation called rotation around the Y axis. and rotation ⁇ about the X axis opposite FIG.
• the actuator of the present invention by the control of six non-sinusoidal currents allows to create fully decoupled forces and moments as a function of the position and the motor torque.
• the magnets employed in the bearing motors 1, 1 bis of the present invention do not contain iron. They are advantageously based on lanthanides otherwise called rare earths, for example samarium cobalt. Alternatively, the magnets may be coordination chemistry magnets, organometallic magnets, for example vanadium di-tetracyanoethylenethide or very low iron content neodymium iron boron and / or purely organic magnets, for example CHNO .
• elements other than iron are preferred. These elements can be based on composite or ceramic.
• Figures 7 and 8 show a magnetic stop 13. This stop is likely to be disposed between the first and second bearing motor 1, 1 bis in a housing 0, as has been shown in particular in Figures 2, 3a to 3c. It should be noted that this magnetic stop can be passive or active.
• the magnetic stop 13 may comprise a series of three concentric rings 13a serving as a stop to the rotor of the two bearing motors and a series of three concentric rings 13b serving as a stop to the stator of the two bearing motors .
• FIGS. 9a, 9b and 9c respectively show the unit force curves along the X axis, the unit force along the Y axis and the unit moment along the Z axis as a function of the rotation angle of the actuator, this for each of the two bearing motors, the dashed curve designating that of one of the bearing motors and the curve with circles designating the other bearing motor.
• the moment curve of a bearing motor can have a zero value for certain angular positions and thus obtaining a constant moment is only possible by combining two angularly offset bearing motors.
• the actuator according to the present invention makes it possible to create fully decoupled forces and moments as a function of the position and the motor torque.
• the actuator with two bearing motors according to the present invention is of robust and economical design. Due to the presence of at least one inductive sensor, a better monitoring and a better control of the movement of the actuator are possible, resulting in a gain in performance and reliability of the actuator.
• Such an actuator with two bearing motors is not subject to friction, the magnetic bearings operating without contact, which reduces the energy consumption of the actuator and increases the life of the actuator.
• the absence of contact also reduces the noise emitted by the actuator during its movement. This allows an increase in the speed with a possible reduction of the size of the actuator bearing motors compared to a actuator of the state of the art.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Mechanical Engineering (AREA)
• Magnetic Bearings And Hydrostatic Bearings (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Permanent Magnet Type Synchronous Machine (AREA)

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• 2012
  • 2012-07-17 FR FR1256906A patent/FR2993699B1/fr not_active Expired - Fee Related
• 2013
  • 2013-07-12 US US14/413,924 patent/US20150162800A1/en not_active Abandoned
  • 2013-07-12 CN CN201380037299.1A patent/CN104508953B/zh not_active Expired - Fee Related
  • 2013-07-12 WO PCT/FR2013/000190 patent/WO2014013147A1/fr active Application Filing
  • 2013-07-12 JP JP2015522139A patent/JP2015528276A/ja active Pending
  • 2013-07-12 EP EP13756541.2A patent/EP2880744A1/de not_active Withdrawn

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