EP2130209A1

EP2130209A1 - Bistable electromagnetic actuator, control circuit for a dual coil electromagnetic actuator, and dual coil electromagnetic actuator including such control circuit

Info

Publication number: EP2130209A1
Application number: EP08787843A
Authority: EP
Inventors: Christophe Cartier-Millon; Gilles Cortese; Michel Lauraire; Cédric BRICQUET; Hugues Filiputti
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2007-03-27
Filing date: 2008-03-25
Publication date: 2009-12-09
Also published as: US8159806B2; AU2011202213B2; AU2011202213A1; WO2008135670A9; WO2008135670A1; BRPI0809429A2; CN102820167A; AU2008248474B2; AU2008248474A1; US20100008009A1

Abstract

The invention relates to a bistable electromagnetic actuator that comprises a magnetic circuit (12) including a magnetic yoke (20) in which a shunt (26) extends perpendicularly to a longitudinal axis (Y) of said yoke, and including a permanent magnet (14) provided between the first face (22) of the yoke and the shunt (26). A mobile core (16) is mounted so as to be capable of axial sliding between a latching position and a release position. A coil (30, 30A, 30B) extending between the shunt (26) and a second face (24) of the yoke generates a first control magnetic flow (φC1 ) for moving the mobile yoke (16) from the release position (PD) to the latching position (PA). A second control magnetic flow (φC2 ) allows the movement of the yoke (16) from the latching position to the release position (PD) under the action of a return spring (36, 37).

Description

BISTABLE ELECTROMAGNETIC ACTUATOR, CIRCUIT FOR CONTROLLING A DOUBLE-COIL ELECTROMAGNETIC ACTUATOR, AND DOUBLE-COIL ELECTROMAGNETIC ACTUATOR COMPRISING SUCH A CONTROL CIRCUIT

TECHNICAL FIELD OF THE INVENTION

The invention relates to a magnetic latching electromagnetic actuator for opening and closing commands of a vacuum interrupter of a cut-off device. The actuator comprises a magnetic circuit having a magnetic yoke in which a shunt extends perpendicularly to a longitudinal axis of said yoke, the shunt being positioned parallel between first and second faces of said yoke. The actuator also comprises at least one permanent magnet with axial magnetization along the longitudinal axis of the yoke, said magnet being positioned between the first face and the shunt. A movable core is mounted to slide axially along the longitudinal axis of the cylinder head between a hooking position and a stall position. At least one coil extends axially between the shunt and the second face and is intended to generate a first control magnetic flux adding to the polarization flux of said at least one permanent magnet to move the movable core from a stall position. at a hooking position, a return spring opposing the displacement of said core. The coil is intended to generate a second magnetic control flux opposing the polarization flux of the permanent magnet and allowing the displacement of the movable core from the hooking position to the stall position under the action of said at least one spring.

The invention relates to a control circuit for electromagnetic actuator with moving core. The circuit comprises at least a first closing control coil for moving the movable core in a closing phase of the actuator. The circuit comprises at least a second opening control coil for moving the magnetic core in an opening phase of the actuator. Said at least two coils of control are coupled by mutual induction. A supply circuit is intended to supply said control coils in the closing and opening phases.

The invention relates to an electromagnetic actuator, comprising a magnetic circuit having a magnetic yoke, at least one permanent magnet with axial magnetization along a longitudinal axis of the yoke and a movable core. Said core is mounted to slide axially along the longitudinal axis between a hooking position and a stall position.

STATE OF THE PRIOR ART

The use of magnetic bistable actuators with magnetic latching for the opening and closing commands of a cut-off device, in particular of vacuum interrupter, is known and described in particular in patents (EP1012856B1, EP0867903B1, US6373675B1).

Given the geometry of the magnetic circuit of the various known actuators, it is generally necessary to use large control coils capable of generating electromagnetic fields necessary for the displacement of the control mechanisms. The electrical power control (number of ampere turns) used is very important and the efficiency is low.

In addition, given the positioning of the magnet or magnets in the magnetic circuit, it is possible to observe the risk of demagnetization of said magnets. Indeed, when the magnets are placed in series in the magnetic circuit, the magnetic flux generated by the control coil can oppose that of the magnet and eventually cause the demagnetization of said magnets.

SUMMARY OF THE INVENTION

The invention therefore aims to overcome the disadvantages of the state of the art, so as to provide a high efficiency electromagnetic actuator Energy.

The yoke of the electromagnetic actuator according to the invention comprises the second face having an inner sleeve extending partially around the movable core, the latter being separated from said sleeve by a radial sliding gap remaining uniform during the translational movement of the movable core. The movable core is, in the stall position, separated from the second face of the yoke by a third gap, the shunt being separated from the movable core by a first axial gap.

Advantageously, the sleeve, in the attachment position, covers the movable core over a covering distance.

Preferably, said at least one permanent magnet is separated from the shunt by a fourth gap.

Preferably, the shunt is radially separated from the cylinder head by a fifth gap.

Advantageously, the magnetic mobile core is coupled to a non-magnetic actuator extending along the longitudinal axis to pass through said at least one magnet and the first face of the yoke.

In a particular embodiment, the electromagnetic actuator comprises at least one magnet having a through hole through which the actuating member passes.

In a particular embodiment, the electromagnetic actuator comprises at least two magnets contiguous, said magnets being respectively cut so as to leave a passage hole when they are contiguous.

Advantageously, the electromagnetic actuator comprises four magnets of identical shape.

Preferably, a centering piece is placed in the through hole.

Advantageously, the centering piece protrudes from said at least one magnet of the height of the fourth gap, said piece being in contact with the shunt.

Advantageously, the movable core comprises a frustoconical radial surface intended to stick against the shunt in the attachment position.

Preferably, the movable core has a hole positioned in the radial surface in contact with the third gap.

Preferably, the hole is opening and passes right through the movable core in a direction parallel to the longitudinal axis.

According to a development mode of the invention, the electromagnetic actuator comprises a first coil for producing the first control magnetic flux and a second coil for producing the second control magnetic flux.

Advantageously, a shock absorber is placed in the space formed by the fourth gap.

Advantageously, at least one intermediate element of non-magnetic material is placed in the fifth gap.

The invention relates to a control circuit power supply circuit for electromagnetic actuator comprising at least a first trigger capacitor connected to switching means for connecting said at least one first trigger capacitor in series with said second coil of opening command. Said at least one first trigger capacitor is charged by a voltage induced across said at least one second opening control coil when a closing voltage is applied across said at least one first closing control coil. The switching means is for connecting said at least one trigger capacitor to the second opening control coil. The at least one first trigger capacitor is discharged through said second opening control coil to develop an opening voltage across said coil during the opening phase. Preferably, said at least one first trigger capacitor has a time constant less than the application time of the closing voltage.

Preferably, the absolute value of the opening voltage is equal to a charging voltage of said at least one first triggering capacitor.

In a particular embodiment, the charging voltage of said at least one first triggering capacitor is equal to the value of the voltage induced across said at least one second opening coil when a closing voltage is applied across the terminals. of said at least one first closing control coil, the absolute value of the opening voltage is equal to the absolute value of the induced voltage.

According to an embodiment of the invention, the control circuit comprises at least one second trigger capacitor. The power supply circuit comprises switching means for connecting said at least first and second trigger capacitors in parallel during a closing phase and for connecting said at least first and second trigger capacitors in series during the opening phase, the opening voltage applied to said second control coil being equal to the sum of the voltages induced respectively at the terminals of the trigger capacitors.

Preferably, said first and second trigger capacitors respectively have time constant less than the time of application of the closing voltage.

In a particular embodiment, the absolute value of the opening voltage is equal to the sum of the charging voltages said at least first and second trigger capacitors.

Preferably, the charging voltage of at least one triggering capacitor is equal to the value of the voltage induced across said at least one second opening coil when a closing voltage is applied across said at least one first closing control coil.

Advantageously, the first and second trigger capacitors are of the same value, the absolute value of the opening voltage is equal to twice the absolute value of the induced voltage.

Preferably, said at least first closing coil comprises a first number of turns less than a second number of turns of said at least second opening control coil so that the voltage induced across said at least second coil the opening control is greater than the closing voltage applied to the at least one closing control coil.

Preferably, the switching means comprise controlled switches.

The invention relates to an electromagnetic actuator comprising a magnetic circuit having a magnetic yoke at least one permanent magnet with axial magnetization along a longitudinal axis of the yoke and a movable core mounted to slide axially along the longitudinal axis between a position of hooking and a stall position. The actuator comprises a control circuit as defined above, the coils extending axially along the longitudinal axis of the yoke, and being intended to generate a first control magnetic flux adding to the polarization flux of said at least one permanent magnet for moving the movable core from a stall position to a latching position. The action of at least one return spring opposes the displacement of said core. The coils are intended to generate a second magnetic control flux opposing the polarization flux of the permanent magnet and allowing the displacement of the movable core from the hooking position to the stall position under the action of said at least one spring.

Preferably, the magnetic yoke comprises a shunt extending perpendicular to a longitudinal axis of said yoke, the shunt being positioned parallel between a first and a second face of said yoke, said at least one permanent magnet being positioned between the first face and the shunt.

Preferably, the coils extend axially between the shunt and the second face.

According to an embodiment of the invention, the second face of the yoke comprises an inner sleeve extending partially around the movable core, the latter being separated from said sleeve by a radial sliding air gap remaining uniform during the translational movement of the movable core. The movable core is, in the stall position, separated from the second face of the yoke by a third gap, a volume between the shunt and the movable core defining a first axial gap.

Preferably, the sleeve, in the attachment position, covers the movable core over a covering distance.

Preferably, the magnetic movable core is coupled to a non-magnetic actuator extending along the longitudinal axis to traverse said at least one magnet and the first face of the yoke.

BRIEF DESCRIPTION OF THE FIGURES

Other advantages and features will emerge more clearly from the following description of particular embodiments of the invention, given by way of non-limiting examples, and represented in the accompanying drawings in which:

Figures 1 and 2 show sectional views of the actuator electromagnetic in two operating positions according to one embodiment of the invention;

FIG. 3 represents an exploded perspective view of the electromagnetic actuator according to FIGS. 1 and 2;

FIG. 4 represents a detailed perspective view of the electromagnetic actuator according to FIGS. 1 and 2;

FIGS. 5A, 5B, 5C and 5D show diagrams of the electromagnetic actuator being actuated from the stall position to the hooking position;

FIGS. 6A, 6B, 6C and 6D show diagrams of the electromagnetic actuator being actuated from the hooking position to the stall position;

Figure 7 shows a schematic block diagram of the electromagnetic actuator coupled to a cut-off device;

FIG. 8 represents curves of the intensity of the forces generated by the electromagnetic actuator;

FIG. 9 represents an electrical diagram of a control circuit according to a first preferred embodiment of the invention;

FIG. 10 represents a curve representative of the evolution of the value of the electric current I as a function of the voltage U applied across a coil of a control circuit according to FIG. 9;

Fig. 11 shows a curve of the induced voltage across an opening coil as a function of the closing voltage applied to the closing coil;

FIG. 12 represents a curve of the charge profile of a trigger capacitor of a control circuit according to FIG. 9;

FIG. 13 represents a circuit diagram of a control circuit according to a second preferred embodiment of the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

According to a first preferred embodiment shown in FIGS. 1 and 2, the magnetic latching bistable actuator comprises a magnetic circuit 12 fixed in ferromagnetic material.

The magnetic circuit 12 comprises a yoke 20 extending along a longitudinal axis Y. The yoke 20 of the magnetic circuit has at its opposite ends first and second parallel faces 22, 24. The faces 22, 24 extend perpendicularly to the longitudinal axis Y of the yoke 20.

Preferably, as shown in Figure 3, the yoke 20 is composed of two elongated metal walls and positioned relative to each other so as to release an internal volume. The two walls are kept parallel by first and second flanges 22, 24 placed respectively at the ends of said walls. According to a particular embodiment, the parallelepiped-shaped yoke 20 has at least two longitudinal faces open on the internal volume.

The magnetic circuit 12 further comprises a shunt 26 for distributing the magnetic flux. The saturable shunt 26 extends radially in a direction parallel to the first flange 22.

The electromagnetic actuator comprises at least one fixed control coil 30 mounted coaxially on an insulating sleeve 32 inside the cylinder head 20. Said at least one coil 30, 30A ₁ 3Bb extends axially between the shunt 26 and the second flask 24.

Inside the internal volume of the yoke 20 is also positioned at least one permanent magnet 14 with axial magnetization. Said at least one magnet is placed between the walls of the yoke 20. The permanent magnet 14 has two coplanar front surfaces of opposite polarities. A first surface is positioned opposite the shunt 26. A second surface is positioned against the wall internal portion of the first flange 22. The front surfaces are substantially perpendicular to the longitudinal axis Y of the yoke 20.

The electromagnetic actuator comprises a mobile core 16 mounted to slide axially in the direction of a longitudinal axis of the cylinder head 20. The displacement of the movable core 16 takes place inside the control coil 30, between two positions of operation subsequently called latching position and stall position.

A first axial gap e1 corresponds to the interval between the shunt 26 and the mobile core 16. This gap is maximum when the movable core is in a second operating position said stall PD as shown in Figure 1. This gap is zero when the movable core is in a first operating position said PA attachment as shown in Figure 2.

Preferably, the core is composed of a cylinder of magnetic or magnetizable material. A first radial face of the cylinder is intended to be in contact with the shunt 26 when the core is in the attachment position PA. A second radial face of the cylinder is intended to be positioned near the inner face of the second flange 24 when the core is in the stall position PD.

The inner face of the second flange 24 comprises an inner sleeve 46 extending partially in an annular space arranged coaxially around the mobile core 16. The movable core 16 is then separated from said sleeve 46 by a second radial air gap e2 remaining uniform during the translational movement of the mobile core 16. Preferably, the sleeve 46, in the attachment position, covers the movable core 16 over a covering distance L. The sleeve 46 is preferably tubular in ferromagnetic material. It may be an integral part of the second flange 24 or be fixed thereto by fixing means. The sliding air gap e2 and the overlap distance L between the movable core 16 and the sleeve 46 are adjusted so that the reluctance of the entire magnetic circuit 20 is as small as possible in the internal volume of the coil 30. The reluctance must be the lowest on the entire stroke of the mobile core 16 between the two positions of operation.

The mobile core 16 in the stall position PD is separated from the inner wall of the second flascue. 24 by a third axial gap e3 corresponding to the gap between the second flange 24 and the movable core 16. This gap e3 is minimal when the movable core is in the stall position PD as shown in FIG. 1.

When the core is in the attachment position, the latter is held glued to the shunt 26 by a magnetic attraction force FA due to a polarization flux φli generated by said at least one permanent magnet 14. The mobile core 16 is intended to to be biased in the stall position PD by at least one return spring 36. The biasing force FR of the return spring 36 tends to oppose the magnetic attraction force FA generated by the permanent magnet 14. In position d the intensity of the magnetic attraction force FA is of greater intensity than the restoring force of the at least one return spring 36.

According to an alternative embodiment of the invention, the movable core 16 has a frustoconical radial surface intended to stick against the shunt 26 in the attachment position.

The first front surface of said at least one permanent magnet 14 is separated from the shunt 26 by a fourth gap e4. Said gap e4 is dimensioned so that it is as small as possible so as not to reduce the efficiency of the magnet 14 but sufficient to avoid any mechanical shock on the magnet or magnets. A shock absorber may be placed in the space formed by the fourth gap e4. This absorber may comprise a gel. This absorber aims to reduce any impact of the shock between the movable core 16 and the shunt 26 when said core moves from the stall position PD to its hooking position PA.

According to a particular embodiment, the shunt 26 extending radially in a direction parallel to the first flange 22 26, is separated from the yoke 20 by a fifth gap e5. At least one intermediate element 33 nonmagnetic material can be placed in the fifth gap e5. This intermediate element serving in particular to support the shunt 26, ensures the holding of the fifth gap e5. The shunt 26 may comprise a variable section. Changing the size of the fifth air gap e5 and / or the section of the shunt 26 makes it possible to adjust the value of the reluctance of said shunt.

The magnetic mobile core 16 is coupled to a non-magnetic actuating member 18 axially through an opening 17 formed in the first flange 22. The non-magnetic actuating member 18 also passes through said at least one magnet 16. The core 16 and the actuating member 18 forming the moving element of the actuator 1.

According to one embodiment of the invention, to facilitate the realization of said at least one magnet 16, the electromagnetic actuator comprises at least two magnets 16 contiguous. Said permanent magnets are respectively cut so as to leave the through hole 17 when they are contiguous. Preferably, a centering piece 19 is placed in the through hole 17. The centering piece 19 protrudes from the at least one magnet 16 by the height of the third fourth gap e4. Said piece is then in contact with the shunt 26. The centering piece 19 allows both the positioning of the magnets, the absorption of a part of the mechanical shocks when the movable core 16 comes into contact with the shunt 26 and finally also intervenes in the guide of the moving element 16, 18. According to an alternative embodiment as shown in FIG. 4, the electromagnetic actuator comprises four magnets 16 of identical shape.

According to a particular embodiment, the mobile element of the actuator 1 is intended to drive a vacuum interrupter of a breaking device.

According to one embodiment of the invention as shown in Figures 1 and 2, the return spring is positioned outside the cylinder head 20. It comprises a first bearing surface on a first external support such as a frame 100 and includes a second bearing surface on a stop 19 placed on the actuated member 18. In the stall position PD, said stop 19 is supported on second external support. By way of example, the second external support may in particular be part of the outer face of the first flange 22. This positioning longitudinal movement of the stop 19 on the actuated member 18 makes it possible to control the length of displacement of the moving element of the actuator 1 and more particularly the length of the third gap e3 in the stall position PD. Indeed, the displacement of the stop 19 along the actuating member 18 makes it possible to adjust the minimum size of this third gap e3. The holding in PA hooking position is guaranteed by said at least one return spring 36, 37.

Said at least one coil 30 is intended to generate in the magnetic circuit 12 a first control magnetic flux φC1. The first control magnetic flux φC1 is intended to add to the polarization flux φU of the permanent magnet 14. Thus the first control magnetic flux φC1 tends to oppose the action of said at least one return spring 36 , 37 so as to move the mobile core 16 from its stall position PD to its hooking position PA. Said at least one coil 30 is intended to generate in the magnetic circuit 12 a second magnetic control flux φC2 which opposes the polarization flux φU of the permanent magnet 14 so as to release the mobile core 16 and to allow its displacement from the hooking position to the stall position PD. The displacement of the movable core 16 from the attachment position PA to the stall position PD is under the action of said at least one return spring 36, 37.

Preferably, the electromagnetic actuator 1 comprises a first coil 30A optimized to produce the first control magnetic flux φC1 and a second coil 30B optimized to produce the second control magnetic flux φC2.

According to one embodiment of the invention as shown in FIG. 7, the electromagnetic actuator 1 may be intended to control a cut-off device 22 comprising in particular a vacuum interrupter 2. The first coil 30A generating the first control flow φC1 is then intended to close the contacts of the vacuum interrupter. In addition, the second coil 30B generating the second control magnetic flux φC2 is then intended to open the contacts of the vacuum interrupter 2. The first coil 30A is then called coil of closure and the second coil 3OB is called opening coil.

Due to the geometrical configuration of the magnetic circuit 12 and in particular by virtue of the positioning of the magnetic shunt 26 with respect to the coil 30 and said at least one magnet 16, said at least one magnet is never crossed by the flux created by the coil or coils 30, 30A, 30B. The risk of demagnetization of the magnet 14 is thus limited.

To move from an open position to a closed position of the contacts of the bulb 2, the operation of the electromagnetic actuator 1 is as follows. As shown in FIG. 5A, two opposing forces apply to the movable core 16. A restoring force FR applied by the return spring 36 to the movable core 16 via a non-magnetic actuating member 18 tends to keep the movable core 16 in a stall position, the contacts being in the open position. The return force FR opposes a first magnetic closing force FA due to the polarization flux φU of the magnet 14. The magnetic closing force FA is of lower intensity than the restoring force FR. As shown in FIG. 5B, the first coil 30A is powered to close the contacts. The first coil 30A generates the first control flow φC1. The first control flow φC1 flows in the same direction as the polarization flux φU of the magnet 14. The first flux produces an electromagnetic FFE closing force. The two closing forces FA, FFE add up and tend to move the movable core 16 from its stall position PD to its hooking position PA. The intensity of the electromagnetic closing force FFE undergoes an exponential variation as shown in FIG. 8. This variation depends directly on the geometry of the coil, in particular its inductance and the type of electrical power supply used.

According to one embodiment of the invention, when the movable core 16 leaves its stall position, the intensity of the electromagnetic closing force FFE is greater than that of the restoring force FR of the return spring 36. zero (offset) of the electromagnetic closing force FFE at the beginning of the displacement of the core 16, will make it possible to obtain a closing force electromagnetic FFE always greater than the restoring force FR during displacement of the mobile core.

The value of the offset is related to the size of the third gap e3, the magnet 14 and the first control flow φC1. As shown in FIG. 5B, the second flange 24 diverts part of the first control flow φC1 from the main magnetic circuit. This diverted flow φCd creates an opposing force temporarily opposing the electromagnetic closing force FFE. The time required to establish an effective electromagnetic closing force FFE for moving the movable core is then lengthened. The dynamic start of the mobile core 16 is then delayed. This delay time allows the electric current flowing in the first coil 30A to reach an intensity sufficient to generate a first effective control flow φC1.

As shown in FIG. 8, when the mobile core 16 begins to move, the potential energy stored by the electromagnetic actuator is then sufficient to guarantee an electromagnetic closing force FFE which will always be of greater intensity than the restoring forces FR. This ensures a closure without downtime and without slowing the mobile core 16.

According to a particular embodiment of the invention as shown in Figure 9, during displacement of the movable core 16 from its stall position PD to its hooking position PA, the electromagnetic closing force FFE will oppose to a second force generated by a second return spring 37. This second spring 37 is intended to apply a contact pressure force to in particular keep closed the electrical contacts of the vacuum bulb 2. This second spring 37 will be compressed under the action of the electromagnetic closing force FFE. As shown in FIG. 8, it is approximately two thirds of the closing stroke of the core 16 that the combined return forces of the first and second return springs 36, 37 will oppose the electromagnetic closing force FFE. When the movable core 16 is in the attachment position PA as shown in FIG. 5D, the supply of the closing coil is cut off. As shown on the FIG. 8, the first magnetic closing force FA is then of greater intensity than the sum of the return forces FR developed by the first and second springs 36, 37. This magnetic catching of the movable core 16 in the hooking position PA can also be combined with a mechanical catch.

To move from a closed position to an open position of the contacts of the bulb 2, in other words from the attachment position PA to the stall position PD of the mobile core 16, the operation of the electromagnetic actuation device 1 is the following. As shown in FIG. 6A, two opposing forces apply to the movable core 16; a magnetic force FA due to the polarization flux φU of the magnet 14 and a restoring force FR resulting from the forces applied by the at least one return spring 36, 37. The magnetic force FA is then of greater intensity than the FR restoring force.

According to the embodiment shown in FIG. 7, the restoring force FR results from the sum of the forces applied jointly by the first and second return springs 36, 37.

As shown in FIG. 6B, the second coil 30B is powered to generate the second control flow φC2. The second control flow φC2 flows in a direction opposite to the polarization flux φU of the magnet 14. The second control flow φC2 produces an electromagnetic opening force FOE. The return force FR and the electromagnetic opening force FOE add up. The resulting opening force is then of greater intensity than the magnetic gripping force FA and tends to move the movable core 16 from its attachment position PA to its stall position PD.

According to an alternative embodiment, the mobile core 16 has a hole 39 positioned in the radial surface in contact with the third gap e3. This hole 39 opens out and passes through said core along its longitudinal axis. When the movable core passes from the attachment position PA to the stall position PD, the hole 39 allows evacuation of the air contained in the volume of the third gap e3. The air can be evacuated instead of being compressed which allows reduce a so-called swabbing effect. This piston effect gives rise to a compressive force that would oppose the movement of the movable core 16.

The two coils 3OA, 3OB can be electrically powered independently. For example, the first closing coil 30A operates at 250 VDC with a current of 10A, while the second coil 30B opening requires a few hundred volts with 4OmA. The diameter of the wire of the two coils 30A, 30B is different. In addition, said coils comprise a different number of turns.

According to an alternative embodiment of the invention, the first and second coils can be put in series during the opening. The second opening coil 3OB will be in short circuit during closing.

The first coil 30A requires a high energy for a given time to close the actuator. For example, the supply time of the first coil 30A is approximately equal to 150ms. This energy comes from the network.

According to an alternative embodiment of the invention, the power supply of the first coil 30A can be performed using an amplitude modulated current pulse. This management of the intensity of the electric current flowing in the first coil 30A can be used to control the speed of the movable core 16 from its stall position PD to its hooking position PA. The reduction of the speed of the mobile core 16 when it comes into contact with the shunt can be of particular interest. The reduction of the impact force between the mobile core and the shunt reduces the mechanical stresses stored by the magnetic circuit.

Conversely, the second coil 3OB needs only a very low energy to open the actuator. This energy can come from a capacitor C1 of low capacity. For example, the capacity will include a dozen MicroFarads with a service voltage of up to several thousand volts. For example, the operating voltage may be 1000Vdc.

Preferably, this capacitor C1 will be of film type in particular film polypropylene. Unlike the chemical capabilities of which. the electrolyte dries, this type of capacitor C1 comprising a polypropylene film has an excellent lifetime. This type of component requires no replacement during the entire life of the electromagnetic actuator. This capacitor C1 via the second coil 30B, acts on the opening in case of a short circuit. In addition, its reliability guarantees a good level of operational safety of the electromagnetic actuator. Given the capacitive capacitance of the capacitor, it can recharge in milliseconds, which is particularly interesting for rapid cycle circuit breakers for medium voltage protection. These circuit breakers generally used for the air network are commonly called Recloser type circuit breakers. The use of this capacitor C1 is of interest when the circuit breaker is used for rapid opening and closing OFOF cycles. This capacitor C1 can be recharged permanently by the mains or by current transformers. Photovoltaic cells can also be used when the device is located at the top of poles.

In addition, as shown in FIG. 9, electromagnetic coupling is present between the two control coils 30A, 30B. Given this coupling, the capacitor C can be recharged by the voltage Uind recovered at the terminals of the second coil 3OB opening when applying a Uferm voltage on the first coil 30A closing. In the event of a loss of mains after closure of the electromagnetic actuator 1 associated with a Recloser type circuit-breaker, the capacitor C1 having been recharged by the energy induced in the opening coil 3OB, an opening is possible immediately without any input. additional energy. As shown in FIG. 9, a switch TH comprising in particular a thyristor or a transistor may be used to connect the capacitor C1 to the second opening coil 30B. Said voltage Uind recovered being high due to the high ratio of the number of turns the second coil, the capacitor would be used as storage but also as a means for clipping any induced voltage.

The invention relates to a control circuit for an actuator The circuit comprises at least a first closure control coil 30A for moving the movable core 16 in a closing phase of the actuator and at least a second opening control coil 30B for moving the mobile magnetic core 16 in an opening phase of the actuator. Said at least one first closing control coil 30A comprises a first number of turns N1. Said at least one second opening control coil 30B comprises a second number of turns N2. Said at least two control coils 30A, 30B are coupled by mutual induction M. Said at least one first coil constitutes the primary circuit of a transformer and said at least second coil constitutes the secondary circuit. The magnetic circuit of the transformer comprises in particular the mobile core 16.

According to a particular embodiment, the control circuit comprises two control coils 30A, 30B. Advantageously, the first number of turns N1 is smaller than the second number of turns N2. The two control coils 3OA, 3OB then constitute a step-up transformer (N2> N1).

The control coils 30A, 30B are intended to generate a first magnetic control flux φC1 in the closing phase and a second magnetic control flux φC2 in the opening phase. In a closing phase, the first closing control coil 30A is supplied with a closing voltage Uferm to generate the first control magnetic flux φC1. In an opening phase, the second opening control coil 30B is powered by an opening voltage Uuv to generate the second control magnetic flux φC2. The opening voltage Uouv is then of sign opposite to the closing voltage Uferm.

According to an exemplary embodiment shown in Figures 1 and 2, said at least two control coils 30A, 30B are contained in a magnetic yoke 20 having a longitudinal axis Y. The movable core 16 is mounted to slide axially along the longitudinal axis Y between a hooking position and a stall position. The coils are preferably concentric and extend axially along the longitudinal axis Y of the yoke 20. The electromagnetic coupling between the control coils 30A, 30B is via the movable core 16 and the magnetic yoke of the actuator.

In addition, the control circuit comprises a supply circuit for supplying said control coils 30A, 30B in the closing and opening phases of the electromagnetic actuator.

According to a first preferred embodiment of the invention as shown in Figure 9, the supply circuit comprises means for placing at least a first trigger capacitor C1 in series with said second opening control coil 30B.

According to this embodiment, the electric control circuit for closing the actuator generates an amplitude modulated closing voltage Uferm. This modulation is PWM type. The modulation of the control signal according to a period T comprises a duty cycle α varying from 0 to 100%. A chopped current corresponding to the Iferm closing current flows in said first closing control coil 30A. If the cyclic modulation ratio α is equal to 100 (α = 100%), a signal having the form of a uniform slot is obtained.

This management of the intensity of the electric current flowing in the first closure control coil 30A can make it possible to control the dynamics of the mobile core 16 in the closing phase.

According to a particular embodiment, the closing voltage is amplitude modulated with a duty cycle of the order of 90%.

In this particular embodiment of the invention, the electrical control circuit is powered by an alternating voltage of an electrical network. Means rectify the AC voltage in DC voltage. The DC voltage supplies electronic control means delivering the amplitude modulated Uferm closure voltage.

The supply of said first closure control coil 30A is managed so that the closing current curve follows classical laws of the physics of the closure of an electromagnetic contactor.

When a closing voltage Uferm is applied across said at least one first closing control coil 30A, a voltage is induced Uind across said second opening control coil 30B. The induced voltage Uind generated at the secondary is proportional to the closing voltage Uferm. The ratio between the induced voltage Uind and the closing voltage Uferm depends on the transformation ratio of the second number of turns N2 of the second opening control coil 30B and the first number of turns N1 of the first closing control coil 30A. . This voltage boosting transformation ratio can be written in the form of

the following equation: {Uind = Uferm. -)

The step-up voltage transformation ratio also depends on the variations generated by the closing dynamics of the movable core 16 of the actuator which varies the magnetic flux. As shown in FIG. 11, the induced voltage Uind has a zero average value.

The control supply circuit comprises switching means D1, D2, TH for connecting said at least one first trigger capacitor C1 in series with said second control coil 30B.

According to the particular embodiment of the invention as shown in FIG. 13, the switching means comprise two rectifying diodes D1, D2 and a controlled switch TH, such as in particular a thyristor or a transistor.

Said at least a first trigger capacitor C1 is charged by the induced voltage Uind across said at least one second opening coil 30B when a closing voltage Uferm is applied across said at least one first control coil. 3OA closure. The charge of the at least one trigger capacitor C1 is made through the two rectifying diodes D1, D2. According to this particular mode of realization, only the positive half-waves of the induced voltage Uind are used to charge said at least one trigger capacitor C1. According to another embodiment not shown, it may be envisaged to rectify the induced voltage for the load of said at least one capacitor. As shown in FIG. 12, the charge profile of the trigger capacitor C1 follows a normal law of exponential charge of electrical capacitance. The charging voltage Uc is then equal to:

t Ucharge = Uind (l -e ^τ )

t is equal to time and τ is the time constant of the capacitor.

At the time of opening, the energy stored in said at least one trigger capacitor C1 may be discharged into the second opening control coil 30B. Thus, it is not necessary to have an auxiliary power source during the opening phase. The opening voltage Uouv applied to said second opening control coil 30B is delivered by said at least one trigger capacitor C1. The absolute value of opening voltage Uouv is equal to the charging voltage Uc of said at least one first trigger capacitor C1.

Preferably, the charging voltage Uc must reach the value in the induced voltage Uind during the time during which the closing voltage Uferm is applied across the closing coil 30A. The trigger capacitors are selected in particular to have a time constant τ as low as possible in comparison with the application time of the closing voltage Uferm.

According to one embodiment of the invention, the charging voltage Uc of said at least one first trigger capacitor C1 is equal to the value of the induced voltage Uind across said at least one second opening coil 30B. The absolute value of the open voltage Uouv is then equal to the absolute value of the induced voltage Uind.

The opening voltage Uouv must be in the opposite direction to the closing voltage Uferm in order to move the movable core 16 in the opening phase of the actuator. The controlled switch TH of the switching means makes it possible to invert the voltage across said at least one trigger capacitor C1.

It is known that the dynamics of a moving core electromagnetic actuator is the image of the electric current flowing in the coil used for the displacement of the core. A curve representative of the evolution of the value of the electric current I as a function of the voltage U applied across said coil is shown in FIG. 10. The slope of the curve originally representative of the acceleration of the core, depends on the ratio between the voltage U and the inductance L of the coil. Since the inductance of the coil L is an intrinsic parameter of the system, increasing the voltage U is the only way to reduce the reaction time of the electromagnetic actuator. The higher the value of the voltage for a given coil, the steeper the slope of the curve, and the greater the acceleration of the mobile core at startup.

In order to increase the opening voltage Uouv, it would be desirable to increase the step-up voltage transformation ratio N1 / N2. However, it is not possible to increase the number of coil turns, in particular of the second opening control coil 30B. Indeed, the maximum size of the control coils 3OA, 3OB is determined by the volume of the actuator and in particular the internal volume of the magnetic yoke. In addition, the solution of decreasing the section of the wire to increase the number of turns without changing the winding volume is also not acceptable. Indeed, a decrease in the section of the winding wire would be accompanied by an increase in the resistance and the inductance of the coil. These changes would have detrimental effects on the charging and discharging time of the trigger capacitors C1, C2. There would be a slowing down of the capacitor charge as well as an increase in the discharge time. This result is incompatible with the desired performance of the actuator especially at the opening where the speed of actuation is sought.

According to a second preferred embodiment of the invention, in order to to increase the opening voltage Uouv to control the second opening control coil 30B, the control circuit comprises at least a second trigger capacitor C2.

In a particular embodiment of the second preferred embodiment as shown in FIG. 13, the control circuit comprises two trigger capacitors C1, C2.

At the time of the closing phase, the supply circuit comprises switching means TH1, TH2, TH3, TH4, D1, D2, D3 for connecting said at least first and second trigger capacitors C1, C2 in parallel with said second opening control coil 3OB.

According to the particular embodiment of the invention as shown in FIG. 13, the switching means comprise three diodes D1, D2, D3 and four controlled switches TH1, TH2, TH3, TH4 such as in particular thyristors or transistors.

When a closing voltage Uferm is applied across said at least one first closing control coil 30A, a voltage Uind is induced across said second opening control coil 30B. Thus, the trigger capacitors C1, C2 are charged by an induced voltage Uind across second opening control coil 30B.

The parallel charge of the trigger capacitors C1, C2 is made through a first and a second diode D1, D3 for the positive polarities and by a controlled switch Th4 and a third diode D2 for the negative polarities. Said controlled switch Th4 is controlled at the same time as closing the actuator to allow the connection in parallel. According to this particular embodiment, only the positive half-waves of the induced voltage Uind are used to charge the trigger capacitors C1, C2. According to another embodiment not shown, it may be envisaged to rectify the induced voltage, in particular by using a diode bridge for charging said at least one capacitor. At the time of the opening phase of the actuator, the supply circuit comprises switching means TH1, TH2, TH3, TH4, D1, D2, D3 for connecting the trigger capacitors C1, C2 in series with said second opening control coil 3OB.

The absolute value of the opening voltage Uouv is equal to the sum of the charging voltages Ud, Uc2, said at least first and second triggering capacitors C1, C2.

According to one embodiment of the invention, the charging voltage Ud, Uc2 of at least one triggering capacitor C1, C2 is equal to the value of the induced voltage Uind across said at least one second opening coil. 3OB when a closing voltage Uferm is applied across said at least one first closing control coil 30A.

Preferably, said first and second trigger capacitors C1, C2 respectively have time constant τ less than the application time of the closing voltage Uferm.

Preferably, the first and second trigger capacitors C1, C2 are of the same value, the absolute value opening voltage Uouv is equal to twice the absolute value of the induced voltage Uind. The discharge of the trigger capacitors C1, C2 connected in series thus makes it possible to double the opening voltage Uouv.

The opening voltage Uouv must be opposite to the closing voltage Uferm in order to move the movable core 16 in the opening phase of the actuator. Th1, Th2, Th3, TM switching means are used to invert the charging voltages Ud, Uc2 across the trigger capacitors C1, C2.

The parallel discharge is performed by a first controlled switch Th1 for the positive polarities and a second controlled switch Th2 for the negative polarities. A third controlled switch Th3 ensures the series connection of the two capacitors. According to the embodiment used, the fact of charging two trigger capacitors C1, C2 in parallel instead of just one only drops the charging voltage by 25%. In addition, discharging two trigger capacitors C1, C2 in series increases the voltage by 60%. This increase in the opening voltage according to the embodiment used makes it possible to obtain performances of desired speed on opening.

The drop of 25% is due to the fact that the transformer that constitutes the two control coils 3OA, 3OB is not a perfect generator. It has an impedance due to the resistance of the wires and to the inductance of the coils. This impedance limits the current supplied by the opening control coil 30B which charges the capacitors.

The value of the trigger capacitors C1, C2 is optimized according to the desired opening speed and the coils dimensioned for a given volume.

According to an alternative embodiment of the preferred embodiments of the control circuit, the electronic control means of the control circuit comprise means for recharging the trigger capacitors C1, C2 when the actuator has been closed. The trigger capacitors C1, C2 are reloaded periodically at a variable frequency depending on the technologies used to compensate for the losses by self discharging. The electronic means then send pulses of short duration in the first closing control coil 30A. The value of the capacity recharge time depends on the intrinsic values of the components. The trigger capacitors C1, C2 are thus recharged by several Uferm control cycles. According to a particular embodiment, the charging pulses have a duration of the order of a few tens of milliseconds and the recharging period is greater than 1/4 hour and can be much longer depending on the technology of the capacitors.

Given that the energy required for opening is low, the trigger capacitors C1, C2 have a low capacitance value. As an example, the capacities will include a dozen MicroFarads having a service voltage of up to several thousand volts. For example, the operating voltage may be 1000Vdc. Given the low capacitive value of the trigger capacitors C1, C2, they can recharge in milliseconds, which is particularly interesting for rapid cycle circuit breakers for medium voltage protection.

In addition they are preferably designed with polypropylene film type technology and have a good service life at least equal to that of the actuator. Its reliability guarantees a good level of operational safety of the electromagnetic actuator.

According to an alternative embodiment of the different embodiments of the invention, the energy required for the control electronics of the switching means, in particular controlled switches TH, TH1, TH2, TH3, TH4 is taken from at least one capacitor. trigger C1, C2.

The invention also relates to a magnetic latching bistable magnetic actuator comprises a magnetic circuit 12 fixed ferromagnetic material. According to a first preferred embodiment shown in Figures 1, 2, 3, the magnetic circuit 12 comprises a yoke 20 extending along a longitudinal axis Y. The yoke 20 of the magnetic circuit has at its opposite ends a first and a second faces 22, 24 parallel. The faces 22, 24 extend perpendicular to the longitudinal axis Y of the yoke 20. Preferably, the yoke 20 is composed of two elongated metal walls and positioned relative to each other so as to release a internal volume. The two walls are kept parallel by first and second flanges 22, 24 placed respectively at the ends of said walls. According to a particular embodiment, the parallelepiped-shaped yoke 20 has at least two longitudinal faces open on the internal volume.

The magnetic circuit 12 further comprises a shunt 26 for distributing the magnetic flux. The saturable shunt 26 extends radially in a direction parallel to the first flange 22. The electromagnetic actuator comprises a control circuit as described above. The control circuit comprises a first control coil 30A and a second fixed control coil 300B mounted coaxially on an insulating sleeve 32 inside the cylinder head 20. Said coils 30A, 30B are concentric and extend axially between the shunt 26 and the second flange 24. The second control coil 3OB is placed outside the first control coil 30A.

Inside the internal volume of the yoke 20 is also positioned at least one permanent magnet 14 with axial magnetization. Said at least one magnet is placed between the walls of the yoke 20. The permanent magnet 14 has two coplanar front surfaces of opposite polarities. A first surface is positioned opposite the shunt 26. A second surface is positioned against the inner wall of the first flange 22. The front surfaces are substantially perpendicular to the longitudinal axis Y of the yoke 20.

The electromagnetic actuator comprises a movable core 16 mounted to slide axially in the direction of a longitudinal axis of the cylinder head 20. The displacement of the mobile core 16 takes place inside the control coils 30A, 30B, between two positions operating system subsequently called AP hooking position and stall position PD.

Preferably, the core is composed of a cylinder of magnetic or magnetizable material. A first radial face of the cylinder is intended to be in contact with the shunt 26 when the core is in the attachment position PA. A second radial face of the cylinder is intended to be positioned near the inner face of the second flange 24 when the core is in the stall position PD. The inner face of the second flange 24 comprises an inner sleeve 46 extending partially in an annular space arranged coaxially around the mobile core 16. The movable core 16 is then separated from said sleeve 46 by a second radial air gap e2 remaining uniform during the translational movement of the mobile core 16. Preferably, the sleeve 46, in the attachment position, covers the movable core 16 over a covering distance L. The sleeve 46 is preferably tubular in ferromagnetic material. It may be an integral part of the second flange 24 or be fixed thereto by fixing means. The sliding gap e2 and the overlap distance L between the movable core 16 and the sleeve 46 are adjusted so that the reluctance of the entire magnetic circuit 20 is as small as possible in the internal volume of the first coil of 3OA command. The reluctance must be the lowest over the entire stroke of the mobile core 16 between the two operating positions.

The mobile core 16 in the stall position PD is separated from the inner wall of the second flange 24 by a third air gap e3 corresponding to the gap between the second flange 24 and the mobile core 16. This gap e3 is minimal when the movable core is in the stall position PD as shown in FIG. 1.

When the core is in the latching position, the latter is held glued against the shunt 26 by a magnetic attraction force FA due to a polarization flux φU generated by said at least one permanent magnet 14. The mobile core 16 is intended to to be biased in the stall position PD by at least one return spring 36. The biasing force FR of the return spring 36 tends to oppose the magnetic attraction force FA generated by the permanent magnet 14. In position d The intensity of the magnetic attraction force FA is greater than the biasing force of said at least one return spring 36 (FIGS. 5A, 5B, 5C, 5D).

According to one embodiment of the invention as shown in Figures 1 and 2, the return spring is positioned outside the cylinder head 20. It comprises a first bearing surface on a first external support such as a frame 100 and includes a second bearing surface on a stop 19 placed on the actuated member 18. In the stall position PD, said stop 19 is supported on second external support. By way of example, the second external support may in particular be part of the outer face of the first flange 22. This longitudinal positioning of the stop 19 on the actuating member 18 makes it possible to control the length of the displacement actuator 1 and more particularly the length of the third air gap e3 in the stall position PD. Indeed, the displacement of the stop 19 along the actuating member 18 makes it possible to adjust the minimum size of this third gap e3. The holding in PA hooking position is guaranteed by said at least one return spring 36, 37.

The first control coil 30A is intended to generate in the magnetic circuit 12 a first magnetic control flux φC1. The first control magnetic flux φC1 is intended to add to the polarization flux φU of the permanent magnet 14. Thus the first control magnetic flux φC1 tends to oppose the action of said at least one return spring 36, 37 so as to move the mobile core 16 from its stall position PD to its hanging position PA.

The second control coil 30B is intended to generate in the magnetic circuit 12 a second magnetic control flux φC2 which opposes the polarization flux φU of the permanent magnet 14 so as to release the mobile core 16 and to allow its movement. from the hooking position to the stall position PD. The displacement of the movable core 16 from the attachment position PA to the stall position PD is under the action of said at least one return spring 36, 37.

According to one embodiment of the invention as shown in FIG. 8, the electromagnetic actuator 1 may be intended to control a cut-off device 22 comprising in particular a vacuum interrupter 2. The first coil 30A generating the first control flow φC1 is then intended to close the contacts of the vacuum interrupter. In addition, the second coil 30B generating the second control magnetic flux φC2 is then intended to open the contacts of the vacuum interrupter 2. The first coil 30A is then called the closing coil and the second coil 30B call opening coil.

Thanks to the geometrical configuration of the magnetic circuit 12 and in particular by virtue of the positioning of the magnetic shunt 26 with respect to the control coils 30A, 30B and of said at least one magnet 16, said at least one magnet is never crossed by the flow created by the control coils 3OA, 3OB. The risk of demagnetization of the magnet 14 is thus limited.

To move from an open position to a closed position of the contacts of the bulb 2, the operation of the electromagnetic actuator 1 is as follows. As shown in FIG. 6A, two opposing forces apply to the moving core 16. A restoring force FR applied by the return spring 36 to the movable core 16 via a non-magnetic actuating member 18 tends to keep the mobile core 16 in a stall position, the contacts being in the open position. The return force FR opposes a first magnetic closing force FA due to the polarization flux φU of the magnet 14. The magnetic closing force FA is of lower intensity than the restoring force FR. As shown in FIG. 5B, the first coil 30A is powered to close the contacts. The first coil 30A generates the first control flow φC1. The first control flow φC1 flows in the same direction as the polarization flux φU of the magnet 14. The first flux produces an electromagnetic FFE closing force. The two closing forces FA, FFE add up and tend to move the movable core 16 from its stall position PD to its hooking position PA. The intensity of the electromagnetic closing force FFE undergoes an exponential variation. This variation depends directly on the geometry of the coil, in particular its inductance and the type of power supply used.

According to one embodiment of the invention, when the movable core 16 leaves its stall position, the intensity of the electromagnetic closing force FFE is greater than that of the restoring force FR of the return spring 36. zero (offset) of the electromagnetic closing force FFE at the beginning of the displacement of the core 16, will obtain an electromagnetic closing force FFE always greater than the restoring force FR during the displacement of the movable core.

The value of the offset is related to the size of the third gap e3, the magnet 14 and the first control flow φC1. As shown in FIG. 10, the second flange 24 diverts part of the first control flow φC1 of the main magnetic circuit. This diverted flow φCd creates an opposing force temporarily opposing the electromagnetic closing force FFE. The time required to establish an effective electromagnetic closing force FFE for moving the movable core is then lengthened. The dynamic start of the mobile core 16 is then delayed. This delay time allows the electric current flowing in the first coil 30A to reach an intensity sufficient to generate a first effective control flow φC1. As shown in FIG. 6B, when the moving core 16 begins to move, the potential energy stored by the electromagnetic actuator is then sufficient to ensure an electromagnetic closing force FFE which will always be of greater intensity than the restoring forces FR. This ensures a closure without downtime and without slowing down the mobile core 16.

According to a particular embodiment of the invention, during displacement of the movable core 6D from its stall position PD to its hooking position PA, the electromagnetic closing force FFE will oppose a second force generated by a second spring 37. This second spring 37 is intended to apply a contact pressure force to in particular keep closed the electrical contacts of the vacuum bulb 2. This second spring 37 will be compressed under the action of the force of electromagnetic closing FFE. It is about two thirds of the closing stroke of the core 16 that the combined return forces of the first and second return springs 36, 37 will oppose the electromagnetic closing force FFE. When the movable core 16 is in the attachment position PA as shown in FIG. 5D, the supply of the closing coil is cut off. The first magnetic closing force FA is then of greater intensity than the sum of the return forces FR developed by the first and second springs 36, 37. This magnetic attachment of the movable core 16 in the attachment position PA can also be combined with a mechanical catch.

To move from a closed position to an open position of the contacts of the bulb 2, in other words from the attachment position PA to the stall position PD of the mobile core 16, the operation of the electromagnetic actuation device 1 is the following. As shown in FIG. 6A, two opposing forces apply to the movable core 16; a magnetic force FA due to the polarization flux φU of the magnet 14 and a restoring force FR resulting from the forces applied by the at least one return spring 36, 37. The magnetic force FA is then of greater intensity than the FR restoring force. According to the embodiment shown in FIG. 6C, the restoring force FR results from the sum of the forces applied jointly by the first and second return springs 36, 37.

For example, the first closing coil 30A of the control circuit operates at 250 Volts DC with a current of 10A, while the second opening control coil 30B requires a few hundred volts with 40MA. The wire diameter of the two control coils 30A, 30B is different. In addition, said coils comprise a different number of turns.

The first coil 30A requires a high energy for a given time to close the actuator. For example, the supply time of the first coil 30A is approximately equal to 150ms. This energy comes from the network. Conversely, the second coil 3OB needs only a very low energy to open the actuator.

According to a particular embodiment, the shunt 26 extending radially in a direction parallel to the first flange 22 26, is separated from the yoke 20 by a fifth gap e5. At least one intermediate element 33 of non-magnetic material may be placed in the fifth gap e5. This intermediate element serving in particular to support the shunt 26, ensures the holding of the fifth gap e5. The shunt 26 may comprise a variable section. Changing the size of the fifth air gap e5 and / or the section of the shunt 26 makes it possible to adjust the value of the reluctance of said shunt.

According to one embodiment of the invention, to facilitate the realization of said at least magnet 16, the electromagnetic actuator comprises at least two magnets 16 contiguous. Said permanent magnets are respectively cut so as to leave the through hole 17 when they are contiguous. Preferably, a centering piece 19 is placed in the through hole 17. The centering piece 19 protrudes from the at least one magnet 16 by the height of the third fourth gap e4. Said piece is then in contact with the shunt 26. The centering piece 19 allows both the positioning of the magnets, the absorption of a part of the mechanical shocks when the movable core 16 comes into contact with the shunt 26 and finally also intervenes in the guidance of the moving equipment 16,

) 18.

Claims

A magnetic latching magnetic actuator for opening and closing commands of a vacuum interrupter of a cutoff device, comprising:

- a magnetic circuit (12) comprising a magnetic yoke (20) in which a shunt (26) extends perpendicularly to a longitudinal axis (Y) of said yoke, the shunt (26) being positioned parallel between a first and a second faces (22, 24) of said cylinder head,

at least one permanent magnet (14) with axial magnetization along the longitudinal axis (Y) of the yoke (20), said magnet being positioned between the first face (22) and the shunt (26),

a movable core (16) mounted to slide axially along the longitudinal axis (Y) of the yoke (20) between a hooking position (PA) and a stall position (PD),

at least one coil (30, 30A, 30B) extending axially between the shunt (26) and the second face (24), and being intended to generate:

a first control magnetic flux (φC1) adding to the polarization flux (φll) of said at least one permanent magnet (14) for moving the mobile core (16) from a stall position (PD) to a position d hooking (PA), at least one return spring (36, 37) opposing the displacement of said core,

a second magnetic control flux (φC2) opposing the polarization flux (φU) of the permanent magnet (14) and allowing the movable core (16) to move from the attachment position (PA) to the position stall (PD) under the action of said at least one return spring (36, 37), characterized in that

the second face (24) of the yoke (20) comprises an inner sleeve (46) extending partially around the movable core (16), the latter being separated from said sleeve (46) by a radial air gap (e2) remaining uniform during translational movement of the movable core (16) and in that the movable core (16) is, in the stall position, separated from the second face (24) of the yoke (20) by a third gap (e3), the shunt (26) being separated from the movable core (16) by a first axial gap (e1).

; 2. Electromagnetic actuator according to claim 1 characterized in that the sleeve (46), in the attachment position, covers the core (16) movable over a covering distance (L).

3. Electromagnetic actuator according to claim 1 or 2 characterized in that said at least one permanent magnet (14) is separated from the shunt (26) by a fourth fourth gap (e4).

4. Electromagnetic actuator according to one of claims 1 to 3 characterized in that the shunt (26) is radially separated from the cylinder head (20) by a fifth gap (e5).

5. Electromagnetic actuator according to any one of the preceding claims characterized in that the movable core (16) is coupled to a magnetic non-magnetic actuating member (18) extending along the longitudinal axis (Y) to pass through said at least one magnet (16) and the first face (22) of the yoke (20).

6. Electromagnetic actuator according to any one of claims 1 to 5 characterized in that it comprises at least one magnet (16) having a through hole (17) through which the actuating member (18).

7. Electromagnetic actuator according to any one of claims 1 to 5 characterized in that it comprises at least two magnets (16) contiguous, said magnets are respectively cut to leave a passage hole (17) when they are contiguous.

8. Electromagnetic actuator according to claim 7 characterized in that it comprises four magnets (16) of identical shape.

9. Electromagnetic actuator according to one of claims 6 to 8 characterized in that it comprises a centering piece (19) placed in the through hole (17).

10. An electromagnetic actuator according to claim 9 characterized in that the centering piece (19) protrudes from said at least one magnet (16) the height of the fourth gap (e4), said piece being in contact with the shunt (26).

11.Electromagnetic actuator according to any one of the preceding claims characterized in that the movable core (16) comprises a frustoconical radial surface intended to stick against the shunt (26) in the attachment position.

12. Electromagnetic actuator according to any one of the preceding claims characterized in that the movable core (16) has a hole (39) positioned in the radial surface in contact with the third gap (e3).

13. Electromagnetic actuator according to claim 12, characterized in that the hole (39) is opening and passes right through the movable core (16) in a direction parallel to the longitudinal axis (Y).

14. An electromagnetic actuator according to any preceding claim characterized in that it comprises a first coil (30A) for producing the first control magnetic flux (φC1) and a second coil (30B) for producing the second flow magnetic control (φC2).

15. Electromagnetic actuator according to any one of the preceding claims characterized in that a shock absorber is placed in the space formed by the fourth gap (e4).

16. An electromagnetic actuator according to any one of the preceding claims characterized in that at least one intermediate element (33) of non-magnetic material is placed in the fifth air gap (e5).

17. A control circuit for a moving core electromagnetic actuator (16), comprising:

At least a first closing control coil (30A) intended to move the mobile core (16) in a closing phase of the actuator,

At least one second opening control coil (30B) for moving the magnetic core in an opening phase of the actuator,

said at least two control coils (30A, 30B) being coupled by mutual induction (M),

A supply circuit for supplying said control coils (30A, 30B) in the closing and opening phases, characterized in that it comprises at least a first trigger capacitor (C1), the circuit for power supply comprises switching means (TH, D1, D2) for:

connecting said at least one first trigger capacitor (C1) in series with said second opening control coil (30B), said at least one first trigger capacitor (C1) being charged by an induced voltage (Uind) to the terminals of said at least one second opening control coil 30B when a closing voltage (Uferm) is applied across said at least one first closing control coil (30A),

- connecting said at least one trigger capacitor (C1) to the second opening control coil (30B), said at least one first trigger capacitor (C1) being discharged through said second opening control coil (30B) ) to develop an opening voltage (Uuv) across said coil during the opening phase.

18. Control circuit according to claim 17, characterized in that the absolute value of the opening voltage (Uuv) is equal to a charging voltage (Uc) of said at least one first trigger capacitor (C1).

19. Control circuit according to claim 17 or 18, characterized in that said at least one first trigger capacitor (C1) has a time constant (τ) less than the application time of the closing voltage (Uferm).

20. Control circuit according to claim 19, characterized in that the charging voltage (Uc) of said at least one first trigger capacitor (C1) is equal to the value of the induced voltage (Uind) at the terminals of said at least one a second opening coil 3OB when a closing voltage (Uferm) is applied across said at least one first closing control coil (30A), the absolute value opening voltage (Uuv) is equal to the value absolute of the induced voltage (Uind).

21. Control circuit according to claim 17, characterized in that it comprises at least a second trigger capacitor (C2), the supply circuit comprising switching means (TH 1, TH 2, TH 3, TH 4, D 1, D2, D3) for:

connecting said at least first and second trigger capacitors (C1, C2) in parallel during a closing phase,

and connect said at least first and second trigger capacitors (C1, C2) in series during the opening phase, the opening voltage (Uuv) applied to said second control coil (30B) being equal to the sum induced voltages respectively at the terminals of the trip capacitors (C1). i

22. Control circuit according to claim 21, characterized in that the absolute value of the opening voltage (Uuv) is equal to the sum of the charging voltages (Ud, Uc2) said at least first and second trigger capacitors (C1, C2).

23. Control circuit according to claim 22, characterized in that the

) charging voltage (Ud, Uc2) of at least one trigger capacitor

(C1, C2) is equal to the value of the induced voltage (Uind) at the terminals of said at least a second opening coil 30B when a closing voltage (Uferm) is applied across said at least one first closing control coil (30A).

24. Control circuit according to claim 23, characterized in that said first and second trigger capacitors (C1, C2) respectively have time constant (τ) less than the application time of the closing voltage (Uferm).

25. Control circuit according to claim 24, characterized in that the first and second trigger capacitors (C1) are of the same value, the absolute value of the opening voltage (Uuv) is equal to twice the absolute value of the voltage. induced (Uind).

26. Control circuit according to any one of claims 17 to 25, characterized in that said at least first closing coil (30A) comprises a first number of turns (N1) less than a second number of turns (N2) of said at least one second opening control coil (30B) so that the voltage (Uind) induced across said at least one second opening control coil (30B) is greater than the closing voltage (Uferm) applied to said at least one closing control coil (30A).

27. Control circuit according to any one of claims 17 to 26, characterized in that the switching means (TH, TH1, TH2, TH3, TH4) comprise controlled switches.

28.Electromagnetic actuator, comprising a magnetic circuit (12) having a magnetic yoke (20), at least one permanent magnet (14) axially magnetized along a longitudinal axis (Y) of the yoke (20) and a core (16) movable axially slidably mounted along the longitudinal axis (Y) between a latching position and a stall position, characterized in that it comprises a control circuit according to claims 17 to 27, the coils extending axially according to longitudinal axis (Y) of the yoke (20), and being intended to generate: a first control magnetic flux (φC1) adding to the polarization flux (φU) of said at least one permanent magnet (14) for moving the movable core (16) from a stall position (PD) to a position d hooking (PA), the action of at least one return spring (36, 37) opposing the displacement of said core,

a second control magnetic flux (φC2) opposing the polarization flux (φU) of the permanent magnet (14) and allowing the movable core (16) to move from the hooking position to the unhooking position ( PD) under the action of said at least one return spring (36, 37).

29.Electromagnetic actuator according to claim 28, characterized in that the yoke (20) comprises a magnetic shunt (26) extending perpendicularly to a longitudinal axis (Y) of said yoke, the shunt (26) being positioned parallel between a first and second faces (22, 24) of said yoke, said at least one permanent magnet (14) being positioned between the first face (22) and the shunt (26).

30.Electromagnetic actuator according to claim 29, characterized in that the coils extend axially between the shunt (26) and the second face (24).

31.Electromagnetic actuator according to any one of claims 28 to 30, characterized in that the second face (24) of the yoke (20) comprises an inner sleeve (46) extending partially around the movable core (16), the latter being separated from said sleeve (46) by a radial air gap (e2) remaining uniform during the translational movement of the movable core (16) and in that the movable core (16) is, in the stall position, separated from the second face (24) of the yoke (20) by a third gap (e3), a volume between the shunt (26) and the movable core (16) defining a first axial gap (e1).

32.Electromagnetic actuator according to claim 31, characterized in that the sleeve (46), in the attachment position, covers the core (16) movable over a covering distance (L).

33.The electromagnetic actuator according to any one of claims 28 to

32, characterized in that said at least one permanent magnet (14) is separated from the shunt (26) by a fourth gap (e4).

34.Electromagnetic actuator according to any one of claims 28 to

33, characterized in that the shunt (26) is radially separated from the cylinder head (20) by a fifth gap (e5).

35. Electromagnetic actuator according to any one of claims 28 to

34, characterized in that the movable core (16) is coupled to a non-magnetic actuator (18) extending along the longitudinal axis (Y) to traverse said at least one magnet (16) and the first face (22) of the yoke (20).