EP1878036B1 - Circuit breaker-contactor with a piezo-electric controlled locking - Google Patents

Abstract

The inventive circuit breaker-contactor (1) comprises a fixed contact, a contact (5) movable (19, 21) with respect to the fixed contact between open and closed positions, means (7) for displacing the movable contact (5) in the closed position thereof, means (9) for displacing the movable contact in the open position. According to said invention, said circuit breaker-contactor comprises means (11) for locking the movable contact (5) in the closed position thereof, a piezo-electric actuator (13) deformable from a rest position to an operating position for displacing the locking means (11) in such a way that the movable contact (5) is enabled to be displaced to the open position by the means (9) for displacing to the open position and an electronic power supply and control unit (15) for feeding and controlling the piezo-electric actuator (13) deformation in the operating position for displacing the locking means (11) in such a way that the movable contact (5) is unlocked in response to an electric current detected by the fixed contact (1).

Description

The invention relates to a circuit breaker-contactor more particularly comprising one or two fixed contacts, a movable contact relative to the fixed contacts between a closed position and an open position, a movable contact moving means in the position of closing, and means for moving the movable contact in the open position.

A circuit breaker-contactor of this type is known in particular from the document EP-A-1 058322 . The moving means of the moving contact closure is a piezoelectric actuator. Under the effect of an anomaly detected in the main circuit on which the circuit-breaker is arranged, an electronic control unit operates on the piezoelectric actuator to trigger the opening of the contacts at a specific time, for example at when the intensity or voltage in the main circuit passes through a point of zero intensity or voltage, called zero point.

In this circuit breaker-contactor, the piezoelectric actuator keeps the moving contact in the closed position as long as the circuit breaker is closed. It has been found that in order to obtain a rapid cutoff when the contact pressure between the fixed contacts and the moving contact is high, it is necessary to have a powerful piezoelectric actuator, that is to say still relatively expensive to actual hour.

One of the aims of the invention is to design a circuit breaker-contactor that overcomes this disadvantage.

For this purpose, the subject of the invention is a circuit-breaker comprising one or two fixed contacts, a movable contact relative to the fixed contacts between a closed position and an open position, a means for moving the movable contact in the closing position, means for moving the movable contact in the open position, and means for locking the movable contact in the closed position, a piezoelectric actuator deforming from a rest position to a working position to move the locking means to allow the moving contact to be moved in the open position by the opening moving means, and an electronic supply and control unit supplying and deforming the piezoelectric actuator in the working position to move the locking means to unlock the moving contact, in response to an electrical intensity detected in the fixed contact or contacts.

The idea is to cause the opening of the main circuit by releasing the potential energy of a powerful elastic means, for example a spring, by moving the locking means of the movable contact. The potential energy of the spring has been accumulated during movement of the movable contact in the closed position. The release of this potential energy causes an extremely fast opening of the circuit breaker-contactor.

The locking means is for example a pawl or a trigger. It can be integrated with the piezoelectric actuator so that the latter acts directly on the moving contact. Preferably, the blocking means is not integrated with the piezoelectric actuator but is designed in the form of a lever for amplifying the deformation of the piezoelectric actuator.

Experience has shown that after about two milliseconds, the main circuit is sufficiently open and that the reaction time of the piezoelectric actuator is also of the order of two milliseconds. Thus, the electronic control unit can operate to allow the circuit breaker to open very exactly at a time when, for example, the intensity is close to zero, without it being caused arc or spark that may affect the life of the circuit breaker and the operation of electronic systems arranged downstream or upstream.

• La figure 1 est une vue en perspective d'un disjoncteur-contacteur selon un premier mode de réalisation de l'invention.
• La figure 2 est représente un oscillogramme illustrant la coupure à point zéro du disjoncteur-contacteur illustré par la figure 1.
• La figure 3 est un vue schématique d'un disjoncteur-contacteur selon un exemple qui ne fait pas partie de l'invention, en position fermée.
• La figure 4 est un vue schématique du disjoncteur-contacteur selon l'exemple, en position ouverte.
• La figure 5 montre le schéma d'une commande électronique du disjoncteur-contacteur.
• La figure 6 montre un moyen de déplacement à pression de vapeur de liquide, en position de repos.
• La figure 7 montre le moyen de déplacement à pression de vapeur de liquide, en position de travail.
• La figure 8 montre un moyen de déplacement à pression de gaz, en position de repos.
• La figure 9 montre le moyen de déplacement à pression de gaz, en position de travail.

Other advantages will become apparent from the description of two embodiments of the invention illustrated by the drawings.

• The figure 1 is a perspective view of a circuit breaker according to a first embodiment of the invention.
• The figure 2 is represents an oscillogram illustrating the zero-point breaking of the circuit breaker illustrated by the figure 1 .
• The figure 3 is a schematic view of a circuit breaker-contactor according to an example which is not part of the invention, in the closed position.
• The figure 4 is a schematic view of the circuit breaker-switch according to the example, in the open position.
• The figure 5 shows the diagram of an electronic control of the circuit breaker-contactor.
• The figure 6 shows a means of displacement at liquid vapor pressure, in the rest position.
• The figure 7 shows the means of displacement at liquid vapor pressure, in working position.
• The figure 8 shows a gas pressure displacement means, in the rest position.
• The figure 9 shows the gas pressure displacement means, in working position.

With reference to the figure 1 , a circuit breaker-contactor comprises two contacts 1.3 fixed relative to each other, a contact 5 movable relative to the fixed contacts 1.3 between a closed position and an open position, and a means 7 moving the movable contact 5 in the closed position.

The circuit breaker-contactor also comprises a means 11 for blocking the movable contact 5 in the closed position, a piezoelectric actuator 13 deforming to move the locking means 11 to unlock the movable contact 5 and allow its movement in the position d opening, and an electronic control unit 15 deforming control the piezoelectric actuator 13 in response to an electrical intensity detected in the fixed contacts 1.3.

All the elements described above are arranged in a housing of insulating material of small dimension, schematically represented on the figure 1 by reference 17. The housing has for example the following dimensions: length, 65 mm; depth, 30mm; height, 50 mm. In particular, the contacts 1 and 3 are fixed with respect to the housing 17.

The movable contact 5 is carried by a carrier arm 19 mounted to rotate about an axis 21. A spring 9 is disposed on each side of the support arm 19 about the axis 21. It rests on a stop 23 of the arm carrier 19 to be deformed in torsion about the axis 21 when the support arm 19 is rotated by the lever 7 serving as a means of manual movement.

The locking means 11 is in the form of a lever arm and acts by a pawl 27 on a locking spike 25 fixed to the support arm 19 to lock the movable contact 5 in the closed position. In the engagement position with the locking nose 25, the pawl 27 takes up the force exerted by the springs 9 deformed in torsion about the axis 21.

In the embodiment illustrated by the figure 1 the piezoelectric actuator 13 comprises an elliptical frame 29 within which piezoelectric elements 31 are arranged. By piezoelectric effect, the major axis 33 of the ellipse is elongated while the minor axis 35 is shortened relative to a rest position. In this working position, the piezoelectric actuator 13 raises the lever arm 11, secured to the frame 29 of the piezoelectric actuator 13 by an attachment point 39 disposed along the minor axis 35. A ballast 37 is provided at the opposite the point of attachment 39 along the minor axis 35 to create a free-free resonance condition at a resonance frequency of the order of 1000 Hz.

To open the circuit-breaker, the piezoelectric actuator 13 is deformed for a very short time to move the lever arm 11 pivotally mounted relative to the housing 17 about a fixed link 24 relative to the housing 17. The lever arm allows to amplify the deformation of the piezoelectric actuator 13. The piezoelectric actuator 13 thus raises the pawl 27 above the locking spout 25 to unlock the rotation of the support arm 19 under the action of the force stored by the torsion springs 9. The movable contact 5 is rotated by the carrier arm 19 to open the circuit breaker-contactor.

In this first embodiment, the piezoelectric actuator 13 acts only to release the lock, that is to say to move the locking means 11 to unlock the movable contact 5 of the closed position under the action of the force stored by the resilient means 9. The closure of the circuit breaker-contactor is performed by the handle 7 to move the carrier arm 19 and at the same time cause the locking of the movable contact 5 in the position of closing. In other words, to reset the circuit breaker-switch, the pawl 27 is driven in displacement by the locking nose 25 to engage with the latter. During this movement, it plays on the bending of the lever arm between the pawl 27 and the attachment point 39, while the piezoelectric actuator 13 is in the rest position.

It has been found experimentally that such a circuit breaker-switch is, from the point of view of the cutoff, at a high level of performance, since it allows zero-point cutoff, which is illustrated by the oscillogram illustrated by the figure 2 , obtained during tests. It can be seen in this photograph that the intensity 16 and the voltage 18 vanish at the zero point, under the effect of an anomaly 22 triggered at the zero point just above.

What must be remembered is that the distance of the movable contact 5 relative to the fixed contacts 1.3 to 3 mm, after 2.5 milliseconds is largely sufficient to interrupt an arc or a spark for voltages of 220 at 230 volts. The release time of the pawl 27 is 0.5 milliseconds and the loss of contact time of 0.8 milliseconds. In total, between the pulse given ten milliseconds before the zero point, a delay of the order of 6 to 8 milliseconds is sufficient after the order to lead to an opening of the main circuit at a correct time.

The speed of intervention of the cutoff is a considerable element of safety in the operation of the circuit-breaker and in the role it plays for the protection of the circuits fed through it.

The figures 3 and 4 illustrate an example, which does not form part of the invention. The elements common to both execution modes retain the same reference.

The circuit breaker-contactor is connected to the main current circuit by a line 2 connected to the fixed contact 1 and by a flexible cable 4 connected to the moving contact 5.

By difference with the first embodiment, the displacement means 7 moves with a first intermediate lever arm 6 between the support arm 19 and the locking means 11. The pawl 25 is no longer attached to the support arm 19 but to this intermediate lever arm 6 movable about an axis of rotation 22 fixed relative to the housing 17. The locking means 11 is an arm of lever mounted pivotably about an axis of rotation 24 fixed relative to the housing 17. The spring 9 is integral with the movable contact 5 being attached to the carrier arm 19 at one end and the housing 17 at an opposite end to deform into elongation. The piezoelectric actuator 13 is connected to the locking means 11 by a second intermediate lever arm 10, rotatably mounted about an axis of rotation 26 and integral with the piezoelectric actuator 13 by a fulcrum 38. An arm transmission 12 connects the locking means 11 to the second intermediate arm 10.

Figure 3 , the circuit breaker is in the closed position. By the catch between the locking nose 27 carried by the locking means 11 and the pawl 25 carried by the intermediate lever arm 6, the locking means 11 blocks the rotation of the arm 19 carrying the movable contact 5 around the axis. A spring 8 is attached to the second intermediate arm 10 at one end and to the housing 17 at an opposite end to hold the locking means in the locking position. The piezoelectric actuator 13 is in the rest position.

Figure 4 , the circuit breaker is in the open position. For opening, the piezoelectric actuator 13 has deformed for a very short time in the working position, extending the minor axis 35 of the elliptical frame 29 and contracting the major axis 33. This has resulted in a displacement of the second arm intermediate lever 10 pivoting about the axis of rotation 26, which has moved the locking means 11 pivotally about the axis of rotation 24 to raise the pawl 27 above the locking nose 25. During these displacements, the second spring 8, integral with the intermediate lever arm 10, has compressed. The unlocking of the pawl 27 has released the first intermediate lever arm 6 in rotation around the axis of rotation 22 and released the support arm 19 in rotation about the axis of rotation 21, under the action of the spring detent 9 integral with the arm 19 carrying the movable contact 5.

To reset the circuit breaker-switch in the closed position, it acts manually on the displacement means 7 to move the first intermediate arm 6 about the axis of rotation 22. During this movement, the spring 9, secured to the arm 19 carrier of the movable contact 5, is compressed. The piezoelectric actuator 13, which was returned to the rest position, is again deformed for a very short time in the working position. This results in a displacement of the second intermediate arm 10 in rotation around the axis of rotation 26, which displaces the locking means 11 pivotally about the axis of rotation 24 to again raise the pawl 27 above the locking nose 25. During these displacements, the second spring 8, secured to the intermediate lever arm 10, is compressed. When the piezoelectric actuator 13 returns to the rest position, the spring 8 expands causing rotation in the opposite direction, both of the intermediate arm 10 about the axis of rotation 26 and the lever arm 11 around the rotation axis 24, until the pawl 27 again engages the locking nose 25 to lock the movable contact 5 in the closed position.

In the first embodiment, the piezoelectric actuator 13 is used only to lift the locking means 11 when opening the circuit breaker-contactor. In the open state, the piezoelectric actuator, no longer powered, returns to its rest position. To reset the circuit breaker-switch, it plays on the bending of the lever arm between the pawl 27 and the attachment point 39, as indicated above.

In the second embodiment, the piezoelectric actuator 13 is also used to lift the locking means 11 when opening the circuit breaker-contactor. And again, in the open state, the piezoelectric actuator 13 returns to its rest position. But to reset the circuit breaker-switch, it is necessary to deform it again in its working position to raise again the locking means 11 for a time necessary to allow the second intermediate arm 6 to pass below the pawl 27.

It is now important to consider the conditions under which the unlock order occurs.

• un moyen 41, par exemple constitué par une boucle inductive, de mesure de l'intensité ou de la tension du courant dans le circuit sur lequel est installé le disjoncteur-contacteur.
• deux chaînes électroniques alimentées par ce moyen de mesure :
  • La première chaîne comprend séquence suivante :
    • un redresseur de courant 43,
    • comparateur 45 permettant de comparer l'intensité instantanée avec un niveau de seuil réglable, par exemple, par un potentiomètre 47. Ce comparateur peut être complété pour prendre en compte une baisse de tension, un défaut de masse ou un défaut d'équilibre du courant en amont et en aval des contacts,
    • en 49, un pas logique de fonction OU permettant d'introduire soit un ordre immédiat soit un ordre provenant d'un moyen retardateur 51, par exemple, un bilame ou un circuit analogique fonctionnant comme un bilame,
    • une mémoire 53 alimentée par le défaut constaté lors des étapes antérieures.
  • La deuxième chaîne parallèle comprend la séquence suivante :
    • un moyen de filtrage 55 pour éliminer les anomalies, tels les bruits électriques,
    • un détecteur de passage à zéro 57,
    • un moyen retardateur 59 permettant de retarder le déclenchement du disjoncteur jusqu'à un point retard. Le retard est ajusté pour tenir compte du temps d'activation de l'actuateur piézoélectrique et de déplacement du contact mobile au delà d'une certaine distance du ou des contacts fixes. Autrement dit, si l'on tient compte du fait que le temps d'activation de l'actuateur piézoélectrique 13 est de deux millisecondes et que le temps de déplacement du contact mobile 5 au-delà d'une distance d'ouverture de 1 millimètre par rapport au contact fixe 1, est de trois millisecondes, il faut retarder la commande d'ouverture de cinq millisecondes pour déclencher l'ouverture dix millisecondes après le point zéro juste précédent. Ces dix millisecondes correspondent à une demi-période d'un courant alternatif de fréquence égal à 50 Hertz. Par conséquent, l'unité de contrôle-commande 15 déclenche l'ouverture du disjoncteur-contacteur exactement au point zéro.

The zero point cut control is implemented by an electronic circuit whose logic is illustrated by the figure 5 . This command is described in the European patent cited in the introduction. She understands :

• means 41, for example constituted by an inductive loop, for measuring the intensity or the voltage of the current in the circuit on which the circuit-breaker is installed.
• two electronic channels fed by this measuring means:
  • The first string includes the following sequence:
    • a current rectifier 43,
    • comparator 45 for comparing the instantaneous intensity with an adjustable threshold level, for example, by a potentiometer 47. This comparator can be completed to take into account a voltage drop, a ground fault or a lack of current balance upstream and downstream of the contacts,
    • at 49, a logical step OR function for introducing either an immediate order or an order from a delay means 51, for example, a bimetallic strip or an analog circuit operating as a bimetallic strip,
    • a memory 53 fed by the defect found in the previous steps.
  • The second parallel chain comprises the following sequence:
    • filtering means 55 for eliminating anomalies, such as electrical noise,
    • a crossing detector 57,
    • a delay means 59 for delaying the tripping of the circuit breaker to a delay point. The delay is adjusted to take into account the activation time of the piezoelectric actuator and displacement of the movable contact beyond a certain distance from the fixed contact (s). In other words, if one takes into account that the activation time of the piezoelectric actuator 13 is two milliseconds and the travel time of the movable contact 5 beyond an opening distance of 1 millimeter relative to the fixed contact 1, is three milliseconds, it is necessary to delay the opening command by five milliseconds to trigger the opening ten milliseconds after the just preceding zero point. These ten milliseconds correspond to half a period of an alternating current of frequency equal to 50 Hertz. Therefore, the control unit 15 triggers the opening of the circuit breaker exactly at the zero point.

The two electronic chains are connected at 61 to an AND logic circuit. The passing signal is then adjusted and amplified at 63. This signal then controls the piezoelectric actuator 13 for opening the circuit breaker-contactor.

• un signal fonctionnel annonçant que le circuit est fermé et ou que le courant passe dans les contacts.
• un signal de défaut en cas de surintensité ou tout autre défaut susceptible d'activer le disjoncteur.
• un signal indiquant que les contacts sont ouverts.

This command can be supplemented by the following signals or commands:

• a functional signal announcing that the circuit is closed and that the current flows through the contacts.
• a fault signal in case of overcurrent or any other fault that could activate the circuit breaker.
• a signal indicating that the contacts are open.

• existence d'une anomalie constatée et mémorisée par la première chaîne électronique, et
• commande en ouverture du disjoncteur-contacteur à l'aide de la deuxième chaîne électronique pour que l'ouverture s'effectue lorsque l'intensité ou la tension en courant alternatif est nulle, c'est-à-dire passe par le point zéro.

Unlocking is thus electronically controlled to trigger the piezoelectric actuator and open the circuit breaker. Thus, the opening of the circuit-breaker is carried out under the following two conditions:

• existence of an anomaly detected and memorized by the first electronic chain, and
• opening control of the circuit breaker with the second electronic chain so that the opening takes place when the intensity or AC voltage is zero, that is to say through the zero point.

In the embodiments described above, the closing of the circuit breaker-contactor is carried out manually by means of the handle 7. But the closure can also be electrically controlled by a second piezoelectric actuator or by an electromagnetic actuator, consisting for example of an electromagnet operating only during the closing phase, so that, with the circuit-breaker closed, the power consumption is zero.

For high intensities, it is also possible to act by pneumatic pressure, hydraulic pressure or vapor pressure enclosed in an enclosure, just as the spring 9 acting during the opening of the circuit breaker-contactor can be replaced by such other analogous systems. .

Figure 4 a solenoid 65 acts on the displacement means 7 of the arm 19 carrying the movable contact 5 to allow the closing of the circuit breaker-contactor, thanks to the translation of a movable rod 67. Figure 3 the solenoid 65 is returned to a rest position.

It is understood that according to the invention, it is possible to implement, simultaneously or not, displacement means, of the movable opening contact, with hydraulic, pneumatic or vapor pressure action which can be substituted for the spring 9. These displacement means are controlled by the electronic control unit 15 and their control is coordinated with the control of the piezoelectric actuator 13 moving the locking means 11 until the release of the movable contact 5.

• à gauche, figure 6, en l'absence de vapeur, un soufflet extensible 77 est en position basse.
• à droite, figure 7, lorsque de la vapeur est produite par un échauffement dû au passage d'un courant, le soufflet 77 est en position haute et son mouvement a provoqué le déplacement d'une tige 67 agissant sur le moyen de déplacement 7 du bras 19 porteur du contact mobile 5.

A means of displacement at vapor pressure is schematically described in Figures 6 and 7 . The control means comprises a closed chamber 69 containing two electrodes 71 and a conductive liquid 73 which can be vaporized when the electrodes 71 are electrically powered 75. Its operation is as follows:

• to the left, figure 6 in the absence of steam, an expandable bellows 77 is in the down position.
• to the right, figure 7 when the steam is produced by a heating due to the passage of a current, the bellows 77 is in the up position and its movement has caused the displacement of a rod 67 acting on the displacement means 7 of the arm 19 carrying the contact mobile 5.

In such an enclosure, Figures 8 and 9 , the water can be replaced by a gas 74 which, under the effect of heating, produced for example by an electrical resistor 79 causes the movement of the bellows 77, which in turn acts to cause the closing of the contacts in place and placing the solenoid as described with reference to the preceding figures 6 and 7.

Such control means are bistable and under these conditions, if the supply of the solenoid or control means which may be substituted for it, is cut when its action is completed, the power consumption is zero outside the operating periods .

The engagement can be carried out at any time if the pressure of the contacts is such that rebounds at the moment of contact are very limited. Time coordination is provided for the action of the solenoid 65 acting on the means of movement of the arm 19 carrying the movable contact 5 during the closing, and the action of the piezoelectric actuator 13 to enable the passage of the locking nose 25 below the pawl 27. Advantageously, the closing or opening of the circuit breaker-contactor can be controlled remotely by any manual or automatic means.

It should be noted that all operating modes of the circuit breaker-switch have been designed to allow piezoelectric or other actuators to operate only very briefly during the opening or closing of the circuit-breaker.

A circuit breaker according to the invention can be miniaturized, which allows it to use for example a piezoelectric actuator for closing and another for opening and allows it to operate very quickly and therefore at higher frequencies. The circuit breaker-contactor is thus capable of controlling the operating sequences of X-ray or laser beams used in particular in medical scanners, such as those described in the patent applications. FR 04.06497 and FR 04.52677 .

Claims (5)

1. Circuit breaker-contactor including:

   - one (1) or two (1, 3) fixed contacts;

   - a contact (5) movable (19,21) relative to the fixed contacts (1,3) between an open position and a closed position;

   - a means (7) for displacing the movable contact (5) into the closed position;

   - a means (9) for displacing the movable contact (5) into the open position;

   - a means (11) for locking the movable contact (5) into the closed position;

   - a piezoelectric actuator (13) deforming from a rest position to an operating position in order to displace the locking means (11) so that the movable contact (5) can be displaced into the open position by the means (9) for displacement into the open position;

   - and an electronic power supply and control unit (15) supplying power to and controlling the deformation of the piezoelectric actuator (13) into the operating position in response to an electrical amperage detected in the fixed contact or contacts (1, 3),

   characterised in that the locking means is a lever (11) pivoting around a fixed link (24), provided with a catch (27) to lock the movable contact (5) by absorbing a potential energy stored by the means (9) for displacement into the open position and joined to the piezoelectric actuator (13) by an attachment point (39) so as to be pivotally controlled by the piezoelectric actuator (13) in order to displace the catch (27) until the movable contact (5) is unlocked by releasing the potential energy stored by the means (9) for displacement into the open position.
2. Circuit breaker-contactor according to claim 1, in which the lever arm (11) deforms by deflecting so that it locks the movable contact (5) in the closed position.
3. Circuit breaker-contactor according to claim 1, in which the means (9) for displacing the movable contact (5) for opening is a spring, a piezoelectric actuator or a means having an electromechanical, hydraulic, pneumatic, liquid vapour pressure or gas vapour pressure action controlled by the electronic control unit.
4. Circuit breaker-contactor according to claim 4, in which the spring (9) deforms by torsion or by elongation.
5. Circuit breaker-contactor according to claim 1, in which the means (7) for closing the movable contact (5) includes a piezoelectric actuator, or a means whose action is electromechanical (65), hydraulic, pneumatic or uses liquid vapour pressure or gas vapour pressure (69) controlled by the electronic control unit (15).

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