Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H57/00—Electrostrictive relays; Piezoelectric relays
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H51/00—Electromagnetic relays
  • H01H51/22—Polarised relays
  • H01H51/2209—Polarised relays with rectilinearly movable armature
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
  • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
  • H01H9/56—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere for ensuring operation of the switch at a predetermined point in the ac cycle
  • H01H9/563—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere for ensuring operation of the switch at a predetermined point in the ac cycle for multipolar switches, e.g. different timing for different phases, selecting phase with first zero-crossing

Definitions

• the present invention relates to an electrical power switch device, monopolar or multipolar, of the relay, contactor or contactor / circuit breaker type, the closing and opening movements between movable contacts and fixed contacts are effected by an approach actuator. and a force actuator.
• the invention also relates to a method for closing and opening the contacts of such a switching device.
• An electrical device of the relay, contactor or contactor / circuit breaker type is a device usually used to effect the electrical switching of a power load, such as for example a motor. For this, it usually comprises, for each power pole, a movable bridge driven by an actuator generally consisting of an electromagnet common to the different poles and provided with a return spring.
• the movable bridge carries a movable contact in single break, or two movable contacts in double break, cooperating with one, respectively two, fixed contact (s), so as to interrupt or ensure the passage of electric current in the poles of power.
• contact pressure springs acting on the movable contacts are usually used.
• the actuator command can come from a manual command from an operator or from an command issued by an automatic control.
• the instant of appearance of these orders is then obviously out of sync with the intensity of the current passing through the different power poles of the switch device at this instant. Therefore, during the opening movement corresponding to the separation between the fixed and mobile contacts, a large electric current can flow in the poles thus creating, in known manner, an electric arc of cut between the fixed and mobile contacts.
• This cutting arc requires a cutting chamber in the device and ultimately accelerates the wear of the contact pads deposited on the fixed and mobile contacts.
• the electromagnet comprises for example a return member, such as a return spring, large enough to have the fastest possible separation between fixed and mobile contacts.
• a first object of the invention is to be able to ensure the break between the fixed and movable contacts of the poles of a switching device at the moment when the alternating electric current flowing in these poles is practically zero. This will reduce the electric arc generated upon cutting, which will advantageously reduce the wear of the contact pads. This will also result in a decrease in the external manifestations of the cuts and a simplification of the breaking chamber.
• a second object of the invention is to be able to eliminate the existing mechanical return members in such a switching device. This will advantageously reduce the size of the actuators for a given nominal current. We will then obtain a switch device of smaller size, simpler in design, consuming less energy and whose contacts will wear out less quickly.
• the invention describes an electrical switch device for switching a load and comprising one or more power poles, each pole comprising a movable bridge provided with at least one movable contact which cooperates with at least one fixed contact of the pole between open and closed positions.
• the switch device comprises an approach actuator acting on the mobile bridge (s) of the switch device so as to allow the distance and the connection between mobile contacts and fixed contacts.
• Each pole includes a force actuator allowing the establishment of the contact pressure or the breaking of contact between the mobile contact (s) of the mobile bridge and the fixed contact (s) of the pole, without using a mechanical return member .
• the approach actuator is constituted by an electromagnetic linear actuator with electrical control or by an actuator of the Voice Coil type.
• the force actuator of a pole comprises at least one piezoelectric element acting on the contact (s) fixed (s) of the pole.
• the switch device comprises means for measuring the current flowing in the pole or poles connected to an electronic control unit capable of controlling the approach actuator (s) and the force actuator (s). Thanks to position determination means, this control unit will allow better control of the dynamics (position, speed, effort) for optimal operation of the switch device: elimination of rebounds, contact pressure regulated as a function of the current flowing in the pole, diagnostic of the wear of the pads.
• the invention also relates to a method of switching a pole in an electrical switch device.
• the method is characterized in that the closing movement of the contacts comprises an approach step allowing the moving bridge to be brought closer to the fixed contact (s) using an approach actuator and includes a contact step allowing the establishment of a contact pressure between movable contacts and fixed contacts of the pole using a force actuator.
• the method is also characterized by the fact that the opening movement of the contacts comprises a breaking step allowing the separation between movable contacts and fixed contacts of the pole using the force actuator and includes a step of moving away of the movable bridge using the approach actuator.
• the breaking step is only carried out when the electric current flowing in the pole is less than a predetermined threshold, just before the current goes to zero.
• FIG. 1 shows a simplified example of an double break contact pole in a switch device according to the invention, in the open position
• FIG. 2 shows the example of FIG. 1 after the approach step
• FIG. 3 shows the example of FIG. 1 in position closed
• - Figure 4 shows a second embodiment of a double-break contact pole
• Figure 5 shows an example of a single-break contact pole
• Figure 6 details a functional diagram of the actuators control 'A switch device according to the invention.
• An electrical power switch device such as a relay, contactor or contactor / circuit breaker has one or more power poles. He is responsible for electrically control an electrical load, such as a motor, a resistor or the like.
• the switch device comprises three power poles corresponding to the three phases L1, L2, L3 of an alternating current, for controlling a motor M.
• a power pole has a movable bridge
• the pole which carries two movable contacts 31 a, 31b electrically connected to each other.
• the pole comprises two power conductors 40a, 40b, the conductor 40a corresponding, for example, to an upstream conductor and the conductor 40b corresponding to a conductor downstream of the switching device.
• These two conductors 40a, 40b each carry at their end a fixed contact respectively 41a, 41b which come into contact with one of the movable contacts respectively 31a, 31b, when the movable bridge 30 is in a closed position allowing the circulation of a electric current between the upstream 40a and downstream 40b conductors.
• the end of the upstream 40a and downstream 40b conductors can form a loop so as to reduce the repulsion of the contacts in the event of a high current.
• the movable bridge 30 is integral with a mechanical member 23, such as a finger, a pusher or the like, which is itself mechanically driven by the movable part 21 of an approach actuator 20.
• the details of a such mechanical connections are conventional in contactors or contactors / circuit breakers and are therefore not shown in the figures in this document.
• the approach actuator 20 is responsible for carrying out the movements of the approach stroke and the movement away from the movable bridge, between the open position (see FIG. 1) and an intermediate position (see FIG. 2) where the fixed contacts 41a, 41b and mobile contacts 31a, 31b are close but separate from each other, as detailed below.
• Each power pole also includes a force actuator 42, responsible for carrying out the movements of the contact crushing stroke, that is to say responsible for establishing the contact pressure or the break between the fixed contacts.
• a force actuator 42 responsible for carrying out the movements of the contact crushing stroke, that is to say responsible for establishing the contact pressure or the break between the fixed contacts.
• 41a, 41b and mobile 31a, 31b of the pole between the intermediate position (see Figure 2) and the closed position (see Figure 3), as detailed below.
• the force actuator 42 is constituted by one or more piezoelectric elements 42a, 42b, 42 'deformable.
• the piezoelectric elements are already known and have the particularity of deforming by slightly increasing in volume, under the action of an electric voltage. This deformation is proportional to the value of the voltage applied to them and is reversible when the voltage disappears. Such elements are therefore bistable and do not require a mechanical return member to return to the initial position. They have the advantage of consuming very little current, but nevertheless of generating a high force during their increase in volume in a very fast response time. In addition, they avoid using moving parts and therefore do not cause wear.
• a power pole comprises two piezoelectric elements 42a, respectively 42b, are placed between a fixed base of the switching device and the end of the power conductors 40a, respectively 40b, carrying the two fixed contacts 41a, 41b respectively. If an electrical voltage is applied to them, the piezoelectric elements 42a, 42b will increase in volume thus creating forces F2a, F2b (see FIG. 3) which will cause a slight deformation of the loop made by the metallic conductors 40a, 40b and therefore a displacement of the fixed contacts 41a, 41b in the direction of the movable contacts 31a, 31b. If the movable bridge 30 is in the intermediate position of FIG.
• this displacement will then be sufficient for the fixed contacts 41a, 41b to come to press and exert pressure on the movable contacts 31 a, 31 b to give the closed position of Figure 3.
• the order of magnitude of the displacement thus caused is less than or equal to 1 mm.
• the piezoelectric elements 42a, 42b are positioned on the movable bridge 30 and act on the movable contacts 31 a, 31 b.
• the movable bridge 30 can include a metallic conductor 33 connecting the movable contacts 31a, 31b to each other.
• This conductor 33 is flexible enough so that, when a voltage is applied to the piezoelectric elements 42a, 42b, their increase in volume can generate a slight deformation of the conductor 33 and therefore a movement of the movable contacts 31 a, 31 b towards the fixed contacts 41 a, 41 b.
• this variant leads to an increase in the total weight of the mobile bridge 30.
• the switch device comprises a single approach actuator 20 for all of the poles.
• the movable part 21 of this actuator 20 therefore drives all of the mechanical members 23 of the different poles.
• the switch device could include a separate approach actuator 20 for each pole. This second solution would be more flexible to use, each pole can then be individually controlled by smaller actuators, although it can be more cumbersome.
• the approach actuator 20 is an electromagnetic actuator with electrical control, for example a bistable linear electromagnet.
• the movable part of the actuator is a movable core 21, such as a plunger core made of magnetic material, surrounded by a fixed carcass 22 carrying a coil traversed by a control current.
• the approach actuator 20 acts on the movable bridges 30 (or on the movable bridge 30 if there is one approach actuator per pole or if the switch device has only one pole), so as to allow the distance and approximation between fixed contacts and movable contacts.
• the movable core 21 moves to a remote position, corresponding to the open position of the pole contacts as shown in Figure 1.
• the approach actuator 20 can also be a linear actuator of the Voice Coil type in which the movable core comprises a coil, traversed by a control current, which moves inside a fixed cylinder head comprising a permanent magnet.
• the movable core comprises a coil
• traversed by a control current which moves inside a fixed cylinder head comprising a permanent magnet.
• a rotary electromagnet provided with a conventional mechanism making it possible to transform a rotary movement into a linear movement.
• the approach actuator 20 therefore does not require the use of return members, of the return spring type, to return the movable core 21 to a determined initial position.
• the actuator 20 is regulated in speed and in position by a control unit 10 so as to obtain a rapid approach stroke and stable positioning.
• This position regulation is particularly important to keep the movable bridge 30 in the closed position, because when the piezoelectric elements 42a, 42b generate the forces F2a, F2b, these forces F2a, F2b must necessarily be compensated by the force F1 generated by the approach actuator 20 for maintain good pressure between fixed and mobile contacts.
• the switching device comprises an electronic control unit 10 which is provided with a processing unit, such as a microprocessor or a microcontroller, and with a memory, and which is connected to measuring means current 11 of the switching device, such as current sensors, capable of delivering signals proportional to the currents flowing in the phases L1, L2, L3.
• the control unit 10 also receives an external piloting command 12 for closing or opening which comes either directly from a user command, or from an order coming from an automation for example. Based on this information, the control unit 10 is capable of sending appropriate commands to the approach actuator 20 and to the force actuators 42 of the different poles.
• control unit 10 must be able to know in real time the position of the movable core 21 in order to be able to regulate in position and speed the position of the approach actuator 20.
• control unit 10 comprises means for determining the position of the movable core 21.
• these position determination means comprise for example a position of the movable core 21 returning position information to the control unit 10.
• control unit 10 does not necessarily include a position sensor because it is capable of estimating this position of the movable core 21 from measurements of the voltage and current flowing in the coil and a calculation of the variation in inductance linked to the variation in air gap, as indicated in l e document FR0200952.
• the method of switching a pole comprises a step approach in which the control unit 10 sends an approach command to the approach actuator 20.
• the resulting electromagnetic force F1 causes displacement of the movable core 21 towards the intermediate position.
• the method of switching a pole also includes a contact step in which the control unit 10 sends a force command to the force actuator 42 of the pole.
• the elements 42a, respectively 42b, of the effort actuator 42 receive a voltage causing their volume to increase and creating a force F2a, respectively F2b, on the fixed contacts 41a, respectively 41 b, sufficient to carry out the contact crushing stroke and to press the fixed contacts 41a, respectively 41b, against the movable contacts 31a, respectively 31b.
• the control unit 10 must balance the different forces by regulating the position of the movable core 21 to prevent it from moving under the action of the forces F2a, F2b so as to ensure a satisfactory contact pressure. Either the approach step and the contact step can take place sequentially or simultaneously.
• the fixed and mobile contacts are therefore far enough apart not to allow the establishment of an electric current between them but are close enough that the small displacement caused during the contact step comes to press the fixed contacts against moving contacts.
• diagnostic functions can also be created on the wear of the contact pads, when there is an approach actuator per pole.
• the approach actuator initiates a closing movement at stable speed, the moment when the current is established in the phase corresponding to the pole is detected by the current sensors 11.
• the method of switching a pole first comprises a breaking step in which the control unit 10 removes the force command sent to the force actuator 42 from the pole.
• the disappearance of the voltage applied to the elements 42a, respectively 42b, of the force actuator 42 will generate a return to their initial shape, thus causing the separation between the fixed contacts 41a, respectively 41b, and the movable contacts 31a, respectively 31 b, and their return to the intermediate position.
• the method for switching a pole includes a distance step during which the control unit 10 sends a distance command to the approach actuator 20. This distance command causes the movable core 21 to move to the remote position, taking the movable bridge (s) 30 in order to reach the open position of the contacts.
• the breaking step is carried out independently pole by pole, at the precise moment of the current passing through zero, that is to say when practically no current flows in the power poles.
• the control unit 10 uses the signals coming from the current sensors 11 and proportional to the currents flowing in the phases L1, L2, L3.
• the control unit 10 verifies that the intensity of the current flowing in the phase corresponding to this pole is less than a predetermined maximum threshold, close to zero.
• control of the actuators by the control unit 10 has the advantage of being able to adapt the level of control of the actuators as a function of the currents flowing in the phases. If a high current, for example a high transient current or a current close to short-circuit, is measured by the current sensors 11 in one or more phases, the control unit 10 is then capable accentuate the controls of the force actuators and regulate the position of the approach actuator to maintain good contact pressure in the poles.
• a high current for example a high transient current or a current close to short-circuit
• each pole of the switch device has only one movable contact 31 'placed at one end of a movable bridge 30' and cooperating with a fixed contact 41 'placed on a fixed conductor 40 ', for example downstream.
• the other end of the movable bridge 30 ' is articulated with a fixed conductor 33', for example upstream.
• a force actuator 42 ′ of piezoelectric type, is disposed between a fixed base of the switching device and the fixed conductor 40 ′ so as to allow the establishment of the contact pressure between the fixed contact 41 ′ and the contact mobile 31 ', when a voltage is applied to the piezoelectric element 42'.
• the movable bridge 30 ' is linked with the movable part 21' of an approach actuator 20 'by means of a mechanical member 23'. The operation of this variant is equivalent to that described above.

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• Relay Circuits (AREA)
• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
• Micromachines (AREA)
• Control Of Linear Motors (AREA)

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• 2002
  • 2002-03-19 FR FR0203522A patent/FR2837616B1/fr not_active Expired - Fee Related
• 2003
  • 2003-03-10 EP EP03735776.1A patent/EP1485931B1/de not_active Expired - Lifetime
  • 2003-03-10 AU AU2003236855A patent/AU2003236855A1/en not_active Abandoned
  • 2003-03-10 CN CNB03805633XA patent/CN1295727C/zh not_active Expired - Fee Related
  • 2003-03-10 ES ES03735776T patent/ES2414457T3/es not_active Expired - Lifetime
  • 2003-03-10 US US10/501,341 patent/US7049912B2/en not_active Expired - Fee Related
  • 2003-03-10 WO PCT/FR2003/000759 patent/WO2003079387A1/fr not_active Application Discontinuation

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