FR2477807A1 - ASSEMBLY FOR THYRISTORS AND TRIACS STARTING - Google Patents

Abstract

MOUNTING INTENDED FOR THE PRIMING OF THYRISTORS, TRIACS AND SIMILAR COMPONENTS AND BY MEANS OF WHICH CAN BE INDUCED, IN A DETECTOR WINDING ASSOCIATED BY MAGNETIC COUPLING WITH A FERROMAGNETIC CORE, A VOLTAGE PULSE WHICH IS USED AS AMORCAGE. FERROMAGNETIC CORE 1 IS A BISTABLE MAGNETIC ELEMENT AND ORGANS 3, 4 ARE PROVIDED TO CREATE A MAGNETIC FIELD WHICH, AT THE LEVEL OF THE BISTABLE MAGNETIC ELEMENT, IS A FUNCTION OF THE POSITION OF A MOBILE OBJECT 8 AND CAN BE INVERTED. THE INVENTION IS APPLICABLE FOR EXAMPLE IN THE FIELD OF MACHINE CONTROLS.

Description

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  The present invention starts from an assembly intended to

  the priming of thyristors, triacs and analogous components

  and by means of which it can be induced, in a

  electrical rolling (detector winding) associated by magnetic coupling to a ferromagnetic core, a voltage pulse which is used as a starting pulse.

  The thyristor and triac control

  switching contacts, as practiced, for example for machine controls when recording moving object moving states, requires that the control signal passing through

  the switching contacts are prepared in an appro-

  urged by measures to stop the rebound

  switches or to remove para-

  control signal sites, which are due to the bouncing

  switching contacts, providing for

  leakage and by means to shorten the duration of the pulses, for example by the use of

  diodes with four layers (trijunction).

  To prevent inadvertent priming of the thyristor

  tor or triac, the trigger input must have a sufficiently low terminal impedance. The extra

  power of control signals thus made necessary.

  must be provided by the control circuit.

  Moreover, it is known to use for the amor-

  thyristors and triacs transformers for

  pulses that are relatively expensive.

  The object of the present invention is to create a

  which can be controlled in particular by mechanical displacements and which is of simple construction and

  operation free of disturbances.

  This object is achieved according to the invention, for a mounting of the type mentioned above, in that the ferromagnetic core is a bistable magnetic element.

  and that organs are intended to create a magnetic field

  which, at the level of the bistable magnetic element, is a function of the position of a moving object and can

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to be reversed.

  As bistable magnetic elements,

  Bistable magnetic switching cores, Wiegand-type wires, the construction and manufacture of which are described in the published German patent application no.

  2 143 326. Wiegand sons are, in their composition,

  homogeneous ferromagnetic wires (for example, an alloy of iron and nickel, preferably 48% iron and 52% nickel, or an alloy of iron and cobalt, or an iron alloy with cobalt and nickel). nickel, or a cobalt alloy with iron and vanadium, preferably 52% cobalt, 38% iron and 10% vanadium), which as a result of a special mechanical and thermal treatment have a soft magnetic core and

  a hard magnetic envelope, that is to say that the enve-

  loppe, has a coercive force superior to that of the nucleus. Wiegand yarns typically have a length of 5 to 50 mm, preferably 20 to 30 mm. If a Wiegand wire, in which the magnetization direction of the soft magnetic core corresponds to the magnetization direction of the hard magnetic envelope, is placed in an external magnetic field whose direction corresponds to the direction of the axis of the wire but whose meaning is opposite

  in the sense of magnetization of the Wiegand wire, then the sense of

  Wiegand's soft core mantle is inverted when a field strength of approximately 16 A / cm is exceeded. This inversion is also called resetting. In case of a new inversion of the direction of the external magnetic field, the direction of magnetization of the nucleus is reversed again as soon as the intensity of the field

  magnetic field exceeds a critical value, of

  that the core and the envelope are again

  magnetized parallel. This inversion of the sense of

  tation takes place very rapidly and is accompanied by a corresponding large variation in the magnetic flux per unit of time (Wiegand effect). This variation of the magnetic flux can induce in a induction coil a short and very strong voltage pulse (pulse Wiegand) (depending on the number of turns and the load resistance of the induction coil)

up to about 12 volts).

  When returning the kernel to its initial state a

  pulse is also produced in an inductive coil.

  this pulse has, compared to the case of the passage of the direction of magnetization antiparallel to that parallel, a substantially lower amplitude and

opposite sign.

  If one chooses as external magnetic field

  an alternating field, capable of reversing the magnetism first

  tation of the core and then that of the envelope and bring them each to the state of magnetic saturation, then

  it occurs as a result of the change in the sense of magnetism

  of the soft magnetic core, Wiegand pulses alternatively having a positive polarity and a

  negative polarity and then we can talk about an excitatory

  symmetrical Wiegand wire. For this, field strengths of about - (80 to 120 A / cm) to + (80 to 120 A / cm) are required. The invention of the magnetization of the envelope also occurs abruptly and also leads to a

  impulse in the induction coil, but this impulse

  sion is much weaker than that induced during

  2S the inversion of the magnetization of the nucleus and is not ex-

in most cases.

  If, on the other hand, one chooses as a magnetic field

  that a field capable of reversing only the magnetization direction of the soft core and not that of the hard shell, then the strong Wiegand pulses only occur with the same polarity and we can then speak of an excitation asymmetrical Wiegand wire. For this it is necessary in a sense a field intensity of

  minus 16 A / cm (to bring the Wiegand wire back to

  tial) and in the opposite direction a field intensity

from about 80 to 120 A / cm.

  It is characteristic of the Wiegand effect that the pulses produced by this effect are, as to their amplitude and width, to a large extent independent of the rate of change of the external magnetic field.

  and have a high signal-to-noise ratio.

  In the context of the invention can also be used bistable magnetic elements designed differently, provided that they include two regions magnetically coupled to each other and having with respect to each other a different magnetic hardness (coercive force) and may, in a manner analogous to Wiegand wires, be used for the generation of pulses by rapid, induced inversion of the magnetization of the soft magnetic region. So it is described, for example

  in German Patent No. 2,514,131 a nucleus of

  Bistable magnetic resistor in the form of a wire which consists of a hard magnetic core (for example nickel-cobalt), an electrically conductive intermediate layer (for example made of copper) deposited on the core and a soft magnetic layer

  (eg nickel-iron) deposited on the inner layer

  médiaire. Another variant further comprises a core formed of an inner conductor devoid of permeance (for example beryllium copper) on which is then

  deposited the hard magnetic layer on which is

  subsequently deposited the intermediate layer which is finally

  covered with the soft magnetic layer. This known bistable magnetic switching core, however, generates lower switching pulses than those

generated by a Wiegand thread.

  If, in accordance with the present invention, the

  bistable magnetic resonance is in a magnetic field

  which as a result of the movement of an object may change

  meaning in the bistable magnetic element,

  then this magnetic field is also capable of reversing

  the magnetization of the bistable magnetic element and

  thus produce in the winding detector, which is as-

  associated with the bistable magnetic element by manual coupling

  a characteristic impulse that can be used to initiate a thyristor or a

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triac.

  For this it is obviously necessary that the

  Bistable magnetic element is oriented so that its two directions of magnetization have a component in the same direction as that of the external field and are preferably as parallel as possible to the latter

  so that the magnetic coupling between the magnetic element

  that bistable and the source of the outer field is also

  strong as possible. In addition, the external magnetic field

  must, at the level of the bistable magnetic element, reach at least the values necessary for excitation

  asymmetric. In one of the senses, one must at least

  HR field strength (in the case of Wiegand wires approx. - 16 A / cm) needed to bring back the magnetic element

  bistable by magnetic means to its previous state (inver-

  the polarity of the soft magnetic region of the

  bistable magnetic element so as to pass it, with respect to the magnetization direction of the magnetic region

  hard, orientation parallel to that antiparallel).

  In the event of a reversal of the field direction, it is then necessary to have a field strength Ha that is sufficient to reverse the polarity of the soft magnetic region of the element again.

  bistable magnetic so as to obtain the pa-

  the sense of magnetization (in the case of

  Wiegand Ha is about 80 to 120 A / cm).

  There are many possibilities for obtaining the desired magnetic field geometry. So we can,

  for example, creating a static magnetic field, inva-

  in space, which has a zero crossing.

  This can be achieved for example by providing two

  pairs of magnetic poles whose alternating polarities

  NEET. In this magnetic field can be moved a

  bistable magnetic element connected to the moving object and which, after a zero crossing in one direction, is brought back to its previous state and, after a zero crossing in

  the other direction produces a characteristic impulse.

  The detector winding can be movable with the bistable magnetic element but it can also

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  be placed near the location of the field where the characteristic pulse is triggered.

  Another preferred embodiment of the invention

  tion uses two static magnetic fields, one of which

  is fixed in relation to the location of the magnetically

  tick bistable while the other is movable. The two fields are opposite. So we can also create,

  at the level of the bistable magnetic element, a magnetic field

  1-0 gnetic whose change of direction depends on the object

  and in this respect whether it is

  bistable magnetic magnet or one of the magnets

  place is in principle irrelevant.

  The magnetic field that is linked to the magnetic element

  fixed bistable tick in the space can be

  created by a winding, traversed by a neckline

  rant and placed on the bistable or

  of the latter, only by a permanent magnet as

  example, a magnetized bar arranged parallel to the

bistable magnetic

  The magnetic field depending on the moving object

  is also advantageously created by magnets per-

  and in this respect it may be

  permanent magnets formed by or connected to the moving object as fixed magnets influenced by an object

  ferromagnetic mobile so as to vary,

  calf of the bistable magnetic element, the intensity of

field established by these magnets.

  In any case it is advantageous that the

  The tick moves with the bistable magnetic element being the weakest magnetic field, which only serves to bring the bistable magnetic element back to its previous state. In this case, when the magnetic field more

  intense depending on the robil object approaches the

  bistable magnetic moment, a characteristic impulse is triggered as soon as the distance of the object the bistable magnetic element becomes lower R a critical threshold while, in case of removal I -7-

  mobile magnetic field, occurs the delivery of the

  Bistable magnetic element in its previous state. This process

  sus is particularly suitable for use in

machine controls.

  In addition to the asymmetric excitation, the symmetrical excitation of the bistable magnetic element is also possible provided that the field strengths, at

  level of the bistable magnetic element, can reach

  in both directions sufficiently large values

  (Hs being approximately + (80 to 120) A / cm in the case of Wiegand wires) but this offers no advantage

  on asymmetric excitation. From the point of view of

  signal retention with high efficiency it is preferable to use as a magnetic

  bistable, a Wiegand wire surrounded by winding de-

  detector. The use of a bistable magnetic element to produce starting pulses has the advantage

  that the duration and amplitude of the pulses are sensi-

  independent of the form and frequency of the

  alternating current exciter. Other influences

  biants, including temperature, do not exert

  more significant influence on the generation of

  sions. If Wiegand threads are used as

  bistable magnetic properties, the half-life

  pulses is 20 micro-seconds.

  In most cases the pulse produced at the moment when the magnetization of the soft magnetic region

  reverses so that the sense of anti-parasitic magnetization

  lele becomes parallel can, without further processing, be used directly for ordering purposes. In case of asymmetric excitation of the bistable magnetic element the pulse produced when the magnetization of the soft magnetic region is reversed so as to obtain the antiparallel orientation is much weaker

  that the momentum produced when the magnetization is invaded

  to get the parallel orientation; in the case of symmetrical excitation of the bistable magnetic element, the pulse produced when the magnetization of the region

  hard magnetic is reversed in order to obtain orienta-

  parallel is much weaker than the S pulse produced when magnetization of the magnetic region

  soft is reversed in order to obtain the anti-

  parallel. The weak impulse can each time, at the

  care, be suppressed by a simple discrimina-

  tor. It is also not necessary to take special technical mounting measures to adapt the gate-type resistor in the case of a thyristor and one can also dispense with bouncing filters and similar organs normally required.

  The pulse transformer according to the invention

  tion is also eminently capable of varying the

  phase of the pulses produced, which is of capital interest for the control of thyristors and triacs. In the known thyristor and triac commands, the phase shift of the pulses is carried out for example by the use of a phase-shifting bridge or a

  rotary transformer in combination with a transformer

  meter for pulses. This mode of dephasing the impulse

  It is expensive and, moreover, it is not suitable for control by displacement processes. Another possibility is to use an electrical circuit

pulse delay.

  The invention makes it possible to achieve the variation of the phase position elegantly by providing, as a second winding, a DC winding which is associated with the magnetic bistable element by magnetic coupling. This second winding creates a

  continuous magnetic field, superimposed on

  calf of the bistable magnetic element, in the magnetic field

  mobile tick who, as a result of his movement, sees his

  intensity vary (fluctuate) at the level of the

  bistable gnetic. Since the field strengths that are required for symmetric excitation or

  asymmetrical bistable magnetic element

  pulses have a value fixed at

  the phase position of the pulses produced in the bistable magnetic element moves, during each period of fluctuation of the intensity of the moving magnetic field, as a result of the addition or the subtraction of a magnetic field continuous static or quasi-static (with respect to the duration of the fluctuation period of the oscillating magnetic field at

  of the bistable magnetic element) and in this respect the

  between the phase position and the intensity of the

  continuous supply to the second winding is linear

  area if the moving magnetic field has, at the level of the bistable magnetic element, a linear appearance in time. But even when using

  of a sinusoidally oscillating magnetic field at

  of such a field being obtained for example by means of a rotating permanent magnet, the relation between the phase position of the pulses and the intensity of the direct current in the

  second winding is still simple.-

  In order to obtain a tight coupling of the element ma-

  bistable gnetic and the second winding it is advisable to place it preferably also around

the bistable magnetic element.

  The static or quasi-static continuous magnetic field at the level of the bistable magnetic element could also be created by a permanent magnet, in which case the variation of the intensity of the continuous field at the level of the bistable magnetic element can be

  obtained, either by removal or reconciliation of the

  permanent mantle, ie, in the case of a stationary permanent magnet, by bringing together and moving away from an object

  ferromagnetic which deforms the field of the permanent magnet.

  NEET. Two embodiments of the invention are

  schematically illustrated in the accompanying drawings in the

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- 10 -

  which: - figure I represents an assembly comprising a

  Wiegand wire placed in the control circuit of a thy-

  ristor; FIG. 2 represents an assembly similar to that of FIG. 1, the Wiegand wire being however

  equipped with a second winding intended for the purpose of

wise;

  - Figure 3 shows a graph intended to elucidate

  der the phase shift of the pulses of a Wiegand wire in the case of a sinusoidally oscillating field; and

  - Figure 4 shows a graph similar to this

  him from Figure 3 for the case of a magnetic field

mobile at a linear pace.

  Figure 1 shows a thyristor 5 in the circuit

  whose load is a resistance RL. The wasting

  6 and the cathode 7 of the thyristor 5 are connected to a

  winding detector 2 surrounding a wire Wiegand 1.

  Magnetic bar 3 serving as a reset magnet

  former is arranged parallel to Wiegand wire 1I.

  On the opposite side of the Wiegand 1 yarn is another bar-

  magnetized water 4, stronger, which also extends parallel

  same as Wiegand 1 but whose sense of

  The magnet bar 4 is on the barrel of a slider 8 which is displaceable in the double direction.

  arrow 9. The slider 8 can be actuated for example

  by a piece of moving machine.

  When the magnet 4 approaches the wire Wiegand so that its distance from it is brought back to a predetermined threshold value, there occurs in the detector winding 2 a pulse Wiegand which initiates the 5. When the magnet 4 moves away again, the wire Wiegand I is emitted to its previous state by the magnet 3, after which it is ready

  to deliver a start pulse again.

  The exemplary embodiment of FIG.

  to that of Figure 1 except that it further comprises a DC winding 11 which is connected to an adjustable direct current source 12 and creates a static magnetic field at the wire Wiegand 1, or quasi-static, which is superimposed on the field of the magnet 4. On the other hand, the reset magnet 3 is no longer provided since its role is filled by the DC winding 11. on the other hand, it would be perfectly possible to entrust the mission of the DC winding 11 to the reset magnet 3 provided that this magnet 3 can change its position relative to the wire Wiegand 1 or that

  the coupling of the magnet 3 and the wire Wiegand 1 is

  a movable ferromagnetic pallet or similar

ford.

  Figures 3 and 4 elucidate the process of

  impulse phasing Wiegand 10 in the case of excitatory

asymmetrical Wiegand wire 1.

  The graph of FIG. 3 is based on the fact that the intensity of the magnetic field created by the magnet 4 at the wire Wiegand 1 varies sinusoidally,

  for example as a result of a crank drive

  on the slider 8 along the double arrow 9 and moving the slider 8 reciprocally sinusotally according to the formula (I) S = SO. sin wt o S represents the displacement of the slider 8 on either side of a median position, S0 is the amplitude of this displacement, w the angular frequency (pulsation)

  of the crank mechanism and t the time.

  So that the magnetic field of the magnet 4, at the level

  wire Wiegand 1, oscillates with the same frequency

  (II) H = H0. sin wto H ,, represents the intensity of the field of the magnet 4 at the wire Wiegand 1 and Ho is the amplitude of this field strength, the magnetic field of the magnet 4 must present, towards the wire Wiegand 1 (direction

  of the double arrow 9), a constant gradient of the inten-

  sity of field, that is to say that it must be linear in space. Means for linearizing the pace of the magnetic field intensity are part of the current state of the art and therefore do not need to be

  specially described in the context of the invention.

  In the field Hl is superimposed the static magnetic field

* tick of the DC winding 11 which has, at the wire Wiegand 1, the intensity H_ and is opposite to the magnetic field of the magnet 4. The resulting magnetic field at the Wiegand wire 1 is then

(III) H = Ho0. sin w t - H_.

  A Wiegand pulse is invariably generated in the presence of the field strength (IV) H = Hz, also called the Hz prime field intensity.

  corresponding phase position w tz = <f of the impulse

  Wiegand 10 is determined by joining (III) and (IV) so as to obtain: (V) sin eZ Hz + H Ho In order to produce the oscillating magnetic field it is possible in many cases to use, instead of a magnet,

  linearly displacing 4, advantageously a magnet

  periodically approaching the Wiegand wire 1 grâ-

this to its rotation.

  The graph of FIG. 4 is based on the fact that the magnetic field of the permanent magnet 4, at the wire Wiegand 1, varies at least within certain limits linearly in time. This can be achieved by linearizing the pace of the magnetic field in the space inside a certain zane located between the magnet 4 and the Wiegand wire 1 and moving the magnet 4,

  less on part of his course, evenly.

  In this linearized zone between the phases w t1 and w t2 (FIG. 4), the field of the magnet 4 presents, at the level of

- 1 -

  of thread Wjigand 1, a pace in the following time: (VI) IL} lLo. 2 + H 1

  o IlLo and H1 are constant values.

  By superposition of the continuous magnetic field

  sensing the intensity H =, which is created by the winding

  11 and is opposed to the field of

  mant 4, the resulting magnetic field in the inner zone

  be the angles of phase 1 t1 and 2 = t2, become: 10 + H 1 - H (VII) H = HLo. + H1 = 2nu A Wiegand pulse 10 is produced according to (IV)

  invariably when H = Hz, so that for the

  corresponding phase phase SZ = W.tz we obtain the following linear relationship: (VIII) z Hz - H1 + H = 2-r HLo Therefore, in the zone between 1 and 2 the variation of the phase position of the pulses Wiegand

  is proportional to the intensity H = of the magnetic field

  static and therefore also proportional to the intensity of the direct current exciting the winding 11. Instead of creating the continuous field H = by means of a winding 4, it can also be created by means of

  of the permanent magnet 3 (FIG. 1) and vary the

  tensity of this field by bringing this magnet closer or

less than Wiegand 1 wire.

  In conclusion, the invention makes it possible, by means of a compact, robust and economical assembly, both the

  production than the phase shift of pulses that are direc-

  able to initiate thyristors and the like. A notable advantage in this respect is that both the generation of pulses and their phase shift can be

  perform in the absence of a source of electrical voltage.

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Claims (13)

  1. - Arrangement for priming thyristors, triacs and similar components and by means of which   can be induced in an electric winding (detection   magnet) coupled by magnetic coupling to a ferromagnetic core, a voltage pulse which is used as a starting pulse, characterized in that the   ferromagnetic core (1) is a magnetic element bis-   table and in that members (3, 4) are provided to create a magnetic field which, at the level of the bistable magnetic element (1), is a function of the position   of a moving object (8) and can be reversed.   2. - Assembly according to claim 1, characterized in that the bistable magnetic element is in a magnetic field having a zero crossing in space and can be subject to relative displacements,   relative to the magnetic field, in the direction of intensity of the field.   3. - Assembly according to claim 1, characterized in that the bistable magnetic element (1) is in a magnetic field resulting from the superposition of a stationary magnetic field, with respect to the current position of the bistable magnetic element (1), and a   movable magnetic field that opposes the magnetic field tick motionless.   4. - Assembly according to claim 3, characterized in that the stationary magnetic field is the field of a winding (11) traversed by a current and which, associated with the bistable magnetic element (1), is preferably placed around this one.   5. - Assembly according to claim 3, characterized in that the stationary magnetic field is the field of a permanent magnet (3) disposed next to the element magnetic bistable.   6. - Assembly according to any one of the   cations 1 to 5, characterized in that the magnetic field   dependent on the moving object is created by a magnet perm   manent (4) or by a set of permanent magnets.   7. - Assembly according to claim 6, characterized in that the moving object is a permanent magnet or a set of permanent magnets.   8. - Assembly according to claim 6, characterized in that the moving object is made of ferromagnetic material and is moved in the magnetic field created by one or several fixed permanent magnets.   9. - Assembly according to any one of the   1 to 8, characterized in that the magnetic element   that bistable (1) is a Wiegand wire.   10. - Assembly according to any one of the   1 to 9, characterized in that the winding detects   tor (2) surrounds the bistable magnetic element (1).   11. - Assembly according to claim 4, characterized in that the winding (11) traversed by a current is   connected to a variable DC source (12).   12. - Assembly according to claim 1, characterized   in that the members (3, 4) for creating the magnetic field   are two permanent magnets or sets of   Permanent mants that are movable * independently   each other with respect to the magnetic element bis-   table or may be influenced by ferro-   magnetic movable independently of one another.   13. - Assembly according to claim 1-1 or 12, characterized in that the magnetic field at the level of   the bistable magnetic element is formed by the super-   Magnetic fields of a permanent magnet   rotating and a permanent magnet moving linearly surely.