EP0076780B1 - Process for reducing the consumption of a stepping motor, and device to carry out this process - Google Patents

Process for reducing the consumption of a stepping motor, and device to carry out this process Download PDF

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Publication number
EP0076780B1
EP0076780B1 EP82810396A EP82810396A EP0076780B1 EP 0076780 B1 EP0076780 B1 EP 0076780B1 EP 82810396 A EP82810396 A EP 82810396A EP 82810396 A EP82810396 A EP 82810396A EP 0076780 B1 EP0076780 B1 EP 0076780B1
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Prior art keywords
voltage
difference
winding
magnitude
representative
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EP82810396A
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German (de)
French (fr)
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EP0076780A1 (en
Inventor
Luciano Antognini
Hans-Jürgen Rémus
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Asulab AG
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Asulab AG
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
    • G04C3/14—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means incorporating a stepping motor
    • G04C3/143—Means to reduce power consumption by reducing pulse width or amplitude and related problems, e.g. detection of unwanted or missing step

Definitions

  • the present invention relates to a method for reducing the consumption of a stepping motor by automatically adapting the duration of each driving pulse supplied to this motor to the load which the latter must drive.
  • the invention also relates to a device for controlling a stepping motor of a timepiece, this device implementing the aforementioned method.
  • Document FR-A-2 200 675 proposes to measure the load which the motor must drive, by permanently measuring the current flowing in the winding of the motor during the application to this winding of a driving pulse. and by interrupting said driving pulse when this current passes through a minimum.
  • the document GB-A-2 006 995 describes a circuit producing sequences of elementary driving pulses separated by periods of interruption and proposes to measure the load driven by the motor by measuring the voltage which appears across the terminals of the motor winding when the latter is placed in open circuit.
  • This measurement is made either after the end of the pulse sequence, or during the time normally occupied by one of the elementary pulses.
  • this voltage is only very indirectly linked to the load driven by the motor. It is composed of the voltage induced in the winding by the rotation of the rotor, which directly depends on this load, and the voltage produced by the inductivity of the winding in response to the sudden interruption of the current flowing through it.
  • This latter voltage which is much greater than the previous one, does not depend on the load driven by the motor, but only on the characteristics of the transistors connected to the winding such as their switching speed and their breakdown voltage.
  • the object of the present invention is to propose a method and a device making it possible to adapt the length of the series of pulses to the load which the motor must drive, in a safe and efficient manner.
  • the voltage U ; induced in the winding of the motor by the rotation of the rotor is a function of the speed of this rotor, and its evolution as a function of time depends on the load which the motor must drive. It is therefore possible to determine this load by measuring the change in the movement induced voltage since the start of the pulse sequence.
  • this induced voltage U increases, reaches a maximum and then decreases differently depending on whether the engine load is low or large. In the first case, this induced voltage increases and decreases at times closer to the start of the pulse sequence than in the second case.
  • Figure 1 shows the equivalent diagram of a stepping motor.
  • the motor winding is represented by a winding 1 of inductivity L and zero resistance, and by a resistance 2 of value R equal to the resistance of the motor winding.
  • a rotor 1 a symbolized by its bipolar permanent magnet, is magnetically coupled to the winding 1,2 by a stator not shown.
  • the induced movement voltage that is to say that which is induced in the winding of the motor by the rotation of the rotor, is symbolized in FIG. 1 by the voltage source 3.
  • the value of this induced voltage is designated published,.
  • the power source of the motor is represented by a source 4 of zero internal resistance and of electromotive force V and by a resistance 5 of value R * equal to the internal resistance of the real source used to power the motor.
  • the motor control circuit is symbolized by a first switch 6 used to connect and disconnect the source 4, 5 of the winding 1, 2 of the motor, and by a second switch 7 used to short-circuit this winding or to eliminate this short-circuit.
  • equation (2) can be written: or:
  • This equation (3) shows that the voltage U i induced in the winding of the motor by the rotation of the rotor can be determined at each interruption period, that is to say at each period during which the source d the power supply is disconnected from the winding and the latter is short-circuited, by measuring the values la and I b of the current at the start and at the end of each of the interruption periods, the quantities R, T 1 and r being known.
  • Determining the value of the term can be done by measuring and storing the value of the current la at the start of the measurement period, by multiplying the measured and stored value by a constant which is known since T and T 1 are known, by measuring the current I b at the end of the measurement period, and by calculating the difference ( ⁇ . la - I b ).
  • This difference is then compared to the value ⁇ , and a signal is produced when this comparison shows that (a. La- I b ) ⁇ .
  • This signal indicates that the voltage U i has become equal to or greater than the threshold voltage U is , and therefore that the instant t, has been reached or exceeded.
  • the various currents la, I b and i are measured by the value of the voltages U a , Ubet u which they produce respectively by passing through a measurement resistor connected in series with the motor winding during periods of interruption of the driving pulse. It is obvious that the various calculations described above are then carried out on the voltages which represent these currents and which are proportional to them.
  • the factor ⁇ is then replaced by a factor where R m is the value of the measurement resistance.
  • Equation (3) above becomes under these conditions:
  • the timepiece shown by way of example in FIG. 2 comprises a circuit 8 generating a time standard signal H, having a frequency equal, for example, to 16,384 Hz.
  • the circuit 8 is formed by a quartz oscillator and a first divider by two stage, and its output is connected to the input of a divider circuit 9 developing, from the time standard signal H various periodic signals including in particular a signal I of frequency equal to 1/2 Hz, a signal J of frequency equal to 1 Hz and a signal K of frequency equal to 64 Hz.
  • the timepiece of FIG. 2 further comprises a pulse-forming circuit 15, the output of which delivers a signal, designated by Z, formed by a series of pulses which pass to state 1 "each time the signal J itself goes to state "1", that is to say every second (see FIG. 2a).
  • the pulses of signal Z return to the state »0 « in response to a signal N delivered by a calculation circuit 26 which will be described later. The instant when this signal N appears therefore determines the duration of the pulses of the signal Z.
  • the pulse forming circuit 15 also delivers an auxiliary signal designated by 0 formed by pulses which pass to the state> 1 "at the same time as the Z pulses but which have a fixed duration of, for example, 7.8 milliseconds.
  • a drive circuit 12 delivers a driving pulse to the winding 11 a of the motor 11.
  • the voltage measured at the terminals of this winding 11 a is designated by U m in Figure 2 a.
  • the energy at the winding 11 a during each driving pulse is delivered by a power source 10.
  • the polarity of the driving pulses is determined by the logic state of the signal I, which alternately takes the state »0« and the state »1« for 1 second.
  • the drive circuit 12 is further arranged so that the driving pulses are chopped in response to a signal M formed of pulses having a high frequency.
  • a signal M formed of pulses having a high frequency.
  • the drive circuit 12 interrupts the connection between the power source 10 and the winding 11 a, and puts the latter in short-circuit.
  • the circuit 12 delivers on an output 12 a voltage proportional to the current which circulates in the winding 11 a. This voltage is used by a measurement circuit 16, an example of which will be described later, to determine the instant t, where the voltage U, induced in the winding 11 a by the rotation of the rotor reaches the reference value U is .
  • this measurement circuit 16 delivers at its output 16 e a signal P, which is in turn used by the calculation circuit 26 to supply the signal N at time t 2 .
  • This calculation circuit 26, is arranged so that the instant t 2 is separated from the start of the driving pulse by a time equal to ( ⁇ . T d + ⁇ ), where ⁇ and ⁇ are the experimentally determined constants mentioned above. This time is therefore equal to the optimal duration of the motor pulse. As the signal N returns the signal Z to the state "0", this signal Z, and therefore the driving pulse, have a duration equal to this optimal duration.
  • the signal M is supplied by a circuit 13, an example of which will be described later.
  • the duration of each pulse of this signal M and the duration of the period of time which separates these pulses are determined by the content of a memory 14.
  • FIG. 3 represents the diagram of an example of a first embodiment 16 of the induced voltage U i of the device represented in FIG. 2.
  • This circuit 16 comprises an input 16 a which receives from circuit 12 the voltage proportional to the current circulating in the winding 11 a, a capacitor 18, one armature of which is connected to ground 19 and the other armature 18 of which is connected to the input 16 a by a transmission gate 20 as well as to the non-inverting input of an operational amplifier 21 whose output is connected directly to its inverting input.
  • the control electrode of the gate 20 is connected to the output Q of a flip-flop of type T 22 whose clock input T receives the signal M via the input 16 c and whose input reset R receives signal H via input 16d.
  • a calculation circuit 23 comprises a voltage divider formed by two resistors 231 and 232 connected in series between the output of the amplifier 21 and the ground, and a differential amplifier 233 whose non-inverting input is connected to the connection point resistors 231 and 232.
  • the circuit 23 further comprises two resistors 234 and 235 connected in series between the output of the amplifier 233 and a voltage generator 24. The inverting input of the amplifier 233 is connected to the connection point resistors 234 and 235.
  • the output of amplifier 233 is connected to the non-inverting input of another differential amplifier 25, the inverting input of which is connected to terminal 16a via a transmission gate 20a.
  • the control electrode of this gate 20 a is connected to the output Q of a flip-flop 22 a of type T, the clock input T of which receives the signal M via an inverter 22 b, the input R receives the signal H.
  • the output of the amplifier 25 constitutes the output 16 e of the measurement circuit 16.
  • the resistors 234 and 235, as well as the voltage supplied by the generator 24 are chosen so that the output of the amplifier 233 delivers a voltage equal to ( ⁇ ⁇ Ua - ⁇ '), where as above.
  • the signal M goes to the state "0", and output Q of the flip-flop 22 a goes to the state "1 for about 30 microseconds.
  • the voltage U b proportional to the current I b which flows in the winding 11 a at this instant is therefore applied to the inverting input of the amplifier 25 which compares it to the voltage ( ⁇ ⁇ Ua - ⁇ ') present at the output of amplifier 233. As long as this voltage U b is greater than this voltage ( ⁇ ⁇ Ua - ⁇ '), the output of amplifier 25 remains in the state »0 «. If the voltage U b is less than this voltage (a.
  • the output of the amplifier 25 delivers the signal P while passing to the state "1", which indicates that the voltage U i induced in the winding by the rotation of the rotor has exceeded the threshold voltage U is .
  • This passage of the output of the amplifier 25 to the state "" marks the instant t 1 .
  • FIG. 3 a represents the diagram of a second embodiment of the circuit 16 for measuring the induced voltage U i .
  • the elements 18, 20, 20 a, 21, 22, 22 a, 22 b, 24, 231 and 232 of this circuit are identical to the elements designated by the same references in Figure 3 and operate in the same way.
  • the signal ⁇ . U is present at the connection point of the resistors 231 and 232 is applied to the non-inverting input of an amplifier 233 '.
  • Two resistors 234 'and 235' are connected in series between the gate 20 a and the output of the amplifier 233 '. The connection point of these two resistors is connected to the inverting input of the amplifier 233 '.
  • the output of the amplifier 233 ' is connected to the non-inverting input of an amplifier 25' whose inverting input is connected to the output of the voltage generator 24.
  • the output of the amplifier 25 ' constitutes in this case the output 16 e of the measurement circuit 16.
  • the resistors 234 'and 235' are chosen so that the output of the amplifier 233 'delivers a voltage equal to ( ⁇ . U a - U b ).
  • the amplifier 25 ' compares this voltage to the voltage ⁇ ' supplied by the generator 24.
  • the output of the amplifier 25 ' supplies the signal P passing to the state' 1 1 when the voltage ( ⁇ ⁇ U a - U b ) becomes greater than the voltage ⁇ ', that is to say again when the voltage U i induced in the winding by the rotation of the rotor becomes greater than the threshold voltage U is .
  • the door 20 a, the flip-flop 22 a and the inverter 22 b can be deleted from the diagrams of FIGS. 3 and 3 a, the input 16 a of the circuit 16 then being connected directly to the inverting input of the amplifier 25, respectively at resistance 235 '.
  • the calculations and comparisons are therefore made continuously on the voltage u produced in the measurement resistor by the current i which flows in the winding 11 a after the start of the interruption period.
  • the signal P is then delivered as soon as the voltage one becomes lower than the voltage ( ⁇ ⁇ U a - ⁇ '), respectively as soon as the voltage (a. Ua - u) becomes higher than the voltage ⁇ '.
  • FIG. 4 represents an exemplary embodiment of the computer circuit 26 of FIG. 2.
  • the circuit 26 comprises a reversible preselection counter 27 having preselection terminals P1, P2, P3 and P4 connected respectively to the output terminals M 1, M 2, M 3 and M 4 of a read-only memory 28.
  • the counter 27 includes a preselection control input PE receiving the signal O via an inverter 29.
  • the clock input CL of the counter 27 is connected to the output of a NAND gate 30 having two inputs each connected to the output of a NAND gate 31, respectively 32.
  • the circuit 26 further comprises a divider circuit 33 providing two signals Q1 and Q2 of respective frequencies f 1 and f 2, in response to the signal H.
  • the signal Q is applied to one of the inputs of door 31 while the signal Q2 is applied to one of the inputs of door 32.
  • a second input of gate 31 is connected to output Q of a T-type flip-flop whose input of clock T is connected to the input terminal 26 a of the circuit 26.
  • a second input of the gate 32 is connected to the output Q of the flip-flop 34.
  • the counting direction control input U / D of the counter 27 is connected to output 0 of flip-flop 34.
  • the counter 27 also has a coincidence output C whose state changes to »1« for a short time when the content of the counter reaches the value zero.
  • This output C is connected to the clock input T of a flip-flop of type T 35 whose output Q constitutes the output 26 b of circuit 26, and whose reset input R is connected to the output Q of a type T flip-flop 101.
  • This latter flip-flop receives the signal 0 on its clock input T and the signal H on its reset input R.
  • the output C of the counter 27 is also connected to the input of reset R of flip-flop 34.
  • FIG. 4 a illustrates the operation of the circuit 26 shown in FIG. 4.
  • the signal 0 is in the state "0", and the input PE of the counter 27 is in the state "1".
  • This counter 27 is therefore blocked in the state where its content corresponds to the content of the memory 28, which is designated by No.
  • the signal 0 goes to "1", putting in the state “0” the input PE of the counter 27 which is thus released and begins to count in the normal direction the pulses coming from the gate 30, from this state No.
  • This counting is carried out at the frequency fl.
  • the output Q of the flip-flop 35 is reset to the state "0" at the start of each driving pulse by the state "1" which appears at the output Q of the flip-flop 101 in response to the signal 0.
  • This state "1" is deleted after approximately 30 microseconds, when signal H changes to state »1«.
  • FIG. 4 a shows that the time T which elapses the start t o of the driving pulse and the appearance, at time t 2 of the signal N at the output 26 b of the circuit 26 is linked to the time T d which flows between the instants t o and t, by the relation: in which f 1 and f 2 are the frequencies of the signals supplied by the outputs Q 1 and Q2 of the divider 33 and No is the number contained in the memory 28, and therefore the number contained by the counter 27 at time t o .
  • FIG. 5 represents an exemplary diagram of the circuits 12 and 15 of FIG. 2.
  • the circuit 15 is formed in this example of two flip-flops of type T whose clock inputs T both receive the signal J delivered by the divider of frequency 9 of FIG. 2 at a frequency of 1 Hz.
  • the reset input R of flip-flop 38 receives the signal K, also supplied by the frequency divider 9, at a frequency of 64 Hz.
  • the output Q of this flip-flop 38 therefore goes to state »1« every second when the signal J goes to state »1 «, and goes back to state »0 « about 7.8 milliseconds later, when signal K in turn goes to state "1".
  • This output Q of flip-flop 38 therefore supplies the signal 0.
  • the reset input R of the flip-flop 39 receives the signal N from the calculation circuit 26 of FIG. 2.
  • the output Q of this flip-flop 39 therefore also goes to state "1 when the signal J goes to the state” 1 ", and returns to the state" 0 "when the circuit 26 delivers the signal N at the instant t 2 determined in the manner described above.
  • This output Q of the flip-flop 39 therefore supplies the signal Z which has a duration equal to the optimum duration of the driving pulse.
  • the circuit 12 of FIG. 2 comprises, in this example, a combinatorial circuit 43 formed by four AND gates 431 to 434, two OR gates 435 and 436 and two inverters 437 and 438.
  • the winding 11a of the motor is connected in a circuit formed by four transmission doors 44 to 47 conventionally connected between the + V terminal of the power source 10 and the ground.
  • Two other transmission doors 48 and 49 each connect one of the terminals of the winding 11 a to a first terminal of a resistor 17, the second terminal of which is connected to ground.
  • the first terminal of this resistor 17 is also connected to the input 16 a of the circuit 16 of FIG. 2.
  • This resistor 17 constitutes the measurement resistance mentioned previously.
  • FIG. 6 shows by way of example the diagram of an embodiment of the circuits 13 and 14 of the device of FIG. 2.
  • the circuit 13 includes two reversible preselection counters 131 and 132.
  • the U / D inputs for controlling the counting direction of these counters 131 and 132 are permanently in the "1" state. These counters 131 and 132 therefore operate as down counters.
  • Their preselection terminals, designated together by Pi are respectively connected to the outputs, designated together by Si, of two memories 141 and 142 which form the memory 14 of the circuit of FIG. 2. These memories 141 and 142 can be, for example, dead memories.
  • the clock inputs CL of the counters 131 and 132 are both connected to the output of the generator 8 (FIG. 2) which delivers the signal H.
  • the counters 131 and 132 each have a coincidence output C which delivers a short pulse each time their content becomes zero. These coincidence outputs C are connected to the inputs of an OR gate 133 the output of which is connected to the clock input T of a flip-flop 134 of type T.
  • the output Q of this flip-flop 134 is connected to the input PE preselection control of the counter 131 and, via an inverter 135, to the PE preselection input of the counter 132.
  • This output Q of the flip-flop 134 is also connected to the output 13 a of the circuit 13.
  • the input PE of the counter 131 on the other hand is in the state "0", and this counter 131 counts the pulses of the signal H.
  • its output C delivers a pulse which is transmitted by the gate 133 at the input T of the flip-flop 134.
  • the output Q of the latter, and the input PE of the counter 131 therefore change to state 1 ".
  • the content of this counter 131 therefore takes a state corresponding to the content of the memory 141, and this counter 131 hangs in this state, which is designated by N 141 in FIG. 6 a.
  • the PE input of counter 132 changes to state »0 «.
  • This counter 132 begins to count the pulses of the signal H.
  • its output C delivers a pulse which is transmitted by the gate 133 to the input T of the flip-flop 134.
  • the output Q of the latter switches back in state "0", and the process described above begins again.
  • the output Q of the flip-flop 134 which delivers the signal M, therefore switches alternately to the state "0" and to the state "1" for durations which depend on the frequency of the signal H and on the content of the memories 141, respectively 142.
  • the duration of the periods of interruption of the driving pulses which is equal to the duration during which the signal M is in the state "1"
  • the duration of the elementary pulses which separate these periods of interruption which is equal to the duration during which the signal M is in the state "0”
  • the manner in which these durations are determined is arbitrary. They can be fixed or vary, in a way that will not be described here, in function of parameters such as the voltage of the power source 10, or the mechanical load driven by the motor, or any other parameter.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Of Stepping Motors (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Valve Device For Special Equipments (AREA)
  • Vehicle Body Suspensions (AREA)
  • Electromechanical Clocks (AREA)

Abstract

The present invention concerns a method and a device for reducing the consumption of a stepping motor by automatically adapting the duration of each drive pulse supplied to said motor to the mechanical load that its rotor is to drive. The method comprises forming each drive pulse by a series of elementary pulses separated by interruption periods, and determining the mechanical load by measuring, during said interruption periods, a parameter which is representative of the variation in the voltage induced in the winding (11a) of the motor by the rotary movement of the rotor.

Description

La présente invention concerne un procédé pour réduire la consommation d'un moteur pas-à-pas en adaptant automatiquement la durée de chaque impulsion motrice fournie à ce moteur à la charge que ce dernier doit entraîner.The present invention relates to a method for reducing the consumption of a stepping motor by automatically adapting the duration of each driving pulse supplied to this motor to the load which the latter must drive.

L'invention concerne également un dispositif de commande d'un moteur pas-à-pas d'une pièce d'horlogerie, ce dispositif mettant en oeuvre le procédé précité.The invention also relates to a device for controlling a stepping motor of a timepiece, this device implementing the aforementioned method.

On a déjà proposé plusieurs procédés pour réduire la consommation d'un moteur pas-à-pas.Several methods have already been proposed for reducing the consumption of a stepping motor.

Le document FR-A-2 200 675, par exemple, propose de mesurer la charge que doit entraîner le moteur, en mesurant en permanence le courant circulant dans l'enroulement du moteur lors de l'application sur cet enroulement d'une impulsion motrice et en interrompant ladite impulsion motrice lorsque ce courant passe par un minimum.Document FR-A-2 200 675, for example, proposes to measure the load which the motor must drive, by permanently measuring the current flowing in the winding of the motor during the application to this winding of a driving pulse. and by interrupting said driving pulse when this current passes through a minimum.

La détection de ce minimum de courant est malaisée en raison des parasites pouvant se superposer au signal de mesure de courant. Il en résulte que ce procédé connu est peu fiable. Par ailleurs, pour certains moteurs ainsi que dans le cas où la charge que doit entraîner le moteur devient importante, ce minimum disparaît de sorte que ce procédé connu devient inapplicable.Detection of this minimum current is difficult due to interference which can be superimposed on the current measurement signal. As a result, this known method is not very reliable. Furthermore, for certain engines as well as in the case where the load which the engine must drive becomes significant, this minimum disappears so that this known process becomes inapplicable.

De même, le document GB-A-2 006 995 décrit un circuit produisant des suites d'impulsions motrices élémentaires séparées par des périodes d'interruption et propose de mesurer la charge entraînée par le moteur en mesurant la tension qui apparaît aux bornes de l'enroulement du moteur lorsque celui-ci est mis en circuit ouvert.Similarly, the document GB-A-2 006 995 describes a circuit producing sequences of elementary driving pulses separated by periods of interruption and proposes to measure the load driven by the motor by measuring the voltage which appears across the terminals of the motor winding when the latter is placed in open circuit.

Cette mesure est faite soit après la fin de la suite d'impulsions, soit pendant le temps occupé normalement par une des impulsions élémentaires.This measurement is made either after the end of the pulse sequence, or during the time normally occupied by one of the elementary pulses.

Cette tension n'est cependant liée que très indirectement à la charge entraînée par le moteur. Elle est composée de la tension induite dans l'enroulement par la rotation du rotor, qui dépend directement de cette charge, et de la tension produite par l'inductivité de l'enroulement en réponse à l'interruption brutale du courant qui le traverse. Cette dernière tension, qui est beaucoup plus grande que la précédente, ne dépend pas de la charge entraînée par le moteur, mais seulement des caractéristiques des transistors reliés à l'enroulement telles que leur vitesse de commutation et leur tension de claquage.However, this voltage is only very indirectly linked to the load driven by the motor. It is composed of the voltage induced in the winding by the rotation of the rotor, which directly depends on this load, and the voltage produced by the inductivity of the winding in response to the sudden interruption of the current flowing through it. This latter voltage, which is much greater than the previous one, does not depend on the load driven by the motor, but only on the characteristics of the transistors connected to the winding such as their switching speed and their breakdown voltage.

La tension mesurée dans les conditions décrites par ce document GB-A-2 006 995 est donc pratiquement inutilisable pour atteindre le but visé.The voltage measured under the conditions described in this document GB-A-2 006 995 is therefore practically unusable for achieving the intended goal.

La présente invention a pour but de proposer un procédé et un dispositif permettant d'adapter la longueur de la suite d'impulsions à la charge que doit entraîner le moteur, de manière sure et efficace.The object of the present invention is to propose a method and a device making it possible to adapt the length of the series of pulses to the load which the motor must drive, in a safe and efficient manner.

Ce but est atteint par le procédé selon la revendication 1 et le dispositif selon la revendication 7.This object is achieved by the method according to claim 1 and the device according to claim 7.

La tension U; induite dans l'enroulement du moteur par la rotation du rotor est fonction de la vitesse de ce rotor, et son évolution en fonction du temps dépend de la charge que doit entraîner le moteur. Il est donc possible de déterminer cette charge par la mesure de l'évolution de la tension induite de mouvement depuis le début de la suite d'impulsions.The voltage U ; induced in the winding of the motor by the rotation of the rotor is a function of the speed of this rotor, and its evolution as a function of time depends on the load which the motor must drive. It is therefore possible to determine this load by measuring the change in the movement induced voltage since the start of the pulse sequence.

Pendant la rotation du rotor, cette tension induite U; croît, atteint un maximum puis décroît de façon différente selon que la charge du moteur est faible ou grande. Dans le premier cas, cette tension induite croît et décroît à des moments plus rapprochés du début de la suite d'impulsions que dans le second cas.During the rotation of the rotor, this induced voltage U ; increases, reaches a maximum and then decreases differently depending on whether the engine load is low or large. In the first case, this induced voltage increases and decreases at times closer to the start of the pulse sequence than in the second case.

En détectant l'instant t, où cette tension induite atteint une valeur prédéterminée judicieusement choise Uis et en mesurant le laps de temps Td s'écoulant entre le début de la suite d'impulsions et cet instant ti, on obtient une mesure de la variation de la tension induite et donc de la valeur instantanée de la charge entraînée par le moteur. Cette mesure étant réalisée alors même que la suite d'impulsions motrice est appliquée sur l'enroulement du moteur, il est dès lors possible de régler la longueur de cette même impulsion motrice en fonction de ladite valeur instantanée de la charge, réalisant ainsi un asservissement direct.By detecting the instant t, where this induced voltage reaches a judiciously chosen predetermined value U is and by measuring the time lapse T d elapsing between the start of the pulse sequence and this instant t i , a measurement is obtained. of the variation of the induced voltage and therefore of the instantaneous value of the load driven by the motor. This measurement being carried out even when the series of driving pulses is applied to the winding of the motor, it is therefore possible to adjust the length of this same driving pulse as a function of said instantaneous value of the load, thus achieving servo-control direct.

On a constaté qu'une durée optimale de la suite d'impulsions, permettant une consommation minimale du moteur tout en garantissant que le rotor termine correctement tous ses pas, peut être déterminée en mesurant le laps de temps Td s'écoulant entre le début de la suite d'impulsions et l'instant t1, et en calculant pour la durée totale de la suite d'impulsions une valeur Top, = λTd + A où À et Δ sont des constantes déterminées expérimentalement pour chaque type de moteuretvala- bles pour tous les moteurs ayant les mêmes caractéristiques électriques et magnétiques.It has been found that an optimal duration of the pulse sequence, allowing minimum consumption of the motor while ensuring that the rotor correctly completes all of its steps, can be determined by measuring the period of time T d elapsing between the start of the pulse sequence and time t 1 , and by calculating for the total duration of the pulse sequence a value T o p, = λT d + A where À and Δ are constants determined experimentally for each type of motors and valid for all motors with the same electrical and magnetic characteristics.

Les caractéristiques et avantages de l'invention seront mieux compris à la lecture de la description qui va suivre de plusieurs modes de réalisation de l'invention, description faite en référence au dessin annexé dans lequel:

  • - la figure 1 est un schéma électrique équivalent d'un moteur pas-à-pas;
  • - la figure 2 est un schéma synoptique d'un dispositif de commande selon un mode de réalisation de l'invention;
  • - la figure 2 a est un diagramme de quelques signaux mesurés dans le schéma de la figure 2;
  • - les figures 3 et 3 a sont des schémas détaillés d'une partie du dispositif de la figure 2, selon deux modes de réalisation de l'invention
  • - la figure 4 est un schéma détaillé d'une deuxième partie du dispositif de la figure 2, selon un mode de réalisation de l'invention;
  • - la figure 4 a est un diagramme en fonction du temps de l'état de comptage du compteur 27 du circuit de la figure 4;
  • - la figure 5 est un schéma détaillé d'une troisième partie du dispositif de la figure 2, selon un mode de réalisation de l'invention;
  • - la figure 5 a représente partiellement les diagrammes du courant circulant dans l'enroulement du moteur ainsi que des signaux mesurés en divers points du circuit de la figure 5;
  • - la figure 6 est un schéma détaillé d'une quatrième partie du dispositif de la figure 2; et
  • - la figure 6 a est un diagramme en fonction du temps de signaux mesurés en divers points du circuit de la figure 6.
The characteristics and advantages of the invention will be better understood on reading the description which follows of several embodiments of the invention, description made with reference to the appended drawing in which:
  • - Figure 1 is an equivalent electrical diagram of a stepping motor;
  • - Figure 2 is a block diagram of a control device according to an embodiment of the invention;
  • - Figure 2a is a diagram of some signals measured in the diagram of Figure 2;
  • - Figures 3 and 3a are detailed diagrams of a part of the device of Figure 2, according to two embodiments of the invention
  • - Figure 4 is a detailed diagram of a second part of the device of Figure 2, according to an embodiment of the invention;
  • - Figure 4a is a diagram as a function of time of the counting state of the counter 27 of the circuit of Figure 4;
  • - Figure 5 is a detailed diagram of a third part of the device of Figure 2, according to an embodiment of the invention;
  • - Figure 5a partially shows the diagrams of the current flowing in the motor winding as well as signals measured at various points in the circuit of Figure 5;
  • - Figure 6 is a detailed diagram of a fourth part of the device of Figure 2; and
  • FIG. 6 a is a diagram as a function of the time of signals measured at various points of the circuit of FIG. 6.

La figure 1 représente le schéma équivalent d'un moteur pas-à-pas. L'enroulement du moteur est représenté par un enroulement 1 d'inductivité L et de résistance nulle, et par une résistance 2 de valeur R égale à la résistance de l'enroulement du moteur. Un rotor 1 a, symbolisé par son aimant permanent bipolaire, est couplé magnétiquement à l'enroulement 1,2 par un stator non représenté. La tension induite de mouvement, c'est-à-dire celle qui est induite dans l'enroulement du moteur par la rotation du rotor, est symbolisée dans la figure 1 par la source de tension 3. La valeur de cette tension induite est désignée par U,.Figure 1 shows the equivalent diagram of a stepping motor. The motor winding is represented by a winding 1 of inductivity L and zero resistance, and by a resistance 2 of value R equal to the resistance of the motor winding. A rotor 1 a, symbolized by its bipolar permanent magnet, is magnetically coupled to the winding 1,2 by a stator not shown. The induced movement voltage, that is to say that which is induced in the winding of the motor by the rotation of the rotor, is symbolized in FIG. 1 by the voltage source 3. The value of this induced voltage is designated published,.

La source d'alimentation du moteur est représentée par une source 4 de résistance interne nulle et de force électromotrice V et par une résistance 5 de valeur R* égale à la résistance interne de la source réelle servant à alimenter le moteur.The power source of the motor is represented by a source 4 of zero internal resistance and of electromotive force V and by a resistance 5 of value R * equal to the internal resistance of the real source used to power the motor.

Enfin, dans ce schéma de la figure 1, le circuit de commande du moteur est symbolisé par un premier interrupteur 6 servant à connecter et à déconnecter la source 4, 5 de l'enroulement 1, 2 du moteur, et par un second interrupteur 7 servant à mettre cet enroulement en court-circuit ou à supprimer ce court-circuit.Finally, in this diagram of FIG. 1, the motor control circuit is symbolized by a first switch 6 used to connect and disconnect the source 4, 5 of the winding 1, 2 of the motor, and by a second switch 7 used to short-circuit this winding or to eliminate this short-circuit.

D'une manière générale, les courants et les tensions intervenant dans le fonctionnement du moteur sont donnés par la relation:

Figure imgb0001
dans laquelle Um est la tension aux bornes du moteur et i est le courant circulant dans son enroulement. Lorsque l'interrupteur 6 est fermé et que l'interrupteur 7 est ouvert, cette tension Um est égale à V - R*. i. Pendant les périodes d'interruption des impulsions motrices, l'interrupteur 6 est ouvert et l'interrupteur 7 est fermé. La tension Um est donc nulle, à condition que la résistance interne de l'interrupteur 7 soit négligeable, ce qui est le cas en pratique. Pendant les périodes d'interruption, l'équation (1) ci-dessus peut donc s'écrire:
Figure imgb0002
 In general, the currents and voltages involved in the operation of the motor are given by the relation:
Figure imgb0001
 in which U m is the voltage across the motor and i is the current flowing in its winding. When the switch 6 is closed and the switch 7 is open, this voltage U m is equal to V - R *. i. During the periods of interruption of the driving pulses, the switch 6 is open and the switch 7 is closed. The voltage U m is therefore zero, provided that the internal resistance of the switch 7 is negligible, which is the case in practice. During periods of interruption, equation (1) above can therefore be written:
Figure imgb0002

Si les périodes d'interruption ont une durée T 1 beaucoup plus courte que la constante de temps r =

Figure imgb0003
de l'enroulement, on peut admettre que
Figure imgb0004
où la et Ib sont les valeurs du courant i au début et à la fin de chaque période d'interruption.If the interruption periods have a duration T 1 much shorter than the time constant r =
Figure imgb0003
 of the winding, we can admit that
Figure imgb0004
 where la and I b are the values of the current i at the beginning and at the end of each interruption period.

Dans ces conditions, en remplaçant L par R · r, l'équation (2) peut s'écrire:

Figure imgb0005
ou encore:
Figure imgb0006
 Under these conditions, by replacing L by R · r, equation (2) can be written:
Figure imgb0005
 or:
Figure imgb0006

Cette équation (3) montre que la tension Ui induite dans l'enroulement du moteur par la rotation du rotor peut être déterminée à chaque période d'interruption, c'est-à-dire à chaque période au cours de laquelle la source d'alimentation est déconnectée de l'enroulement et ce dernier est mis en court-circuit, en mesurant les valeurs la et Ib du courant au début et à la fin de chacune des périodes d'interruptions, les grandeurs R, T 1 et r étant connues.This equation (3) shows that the voltage U i induced in the winding of the motor by the rotation of the rotor can be determined at each interruption period, that is to say at each period during which the source d the power supply is disconnected from the winding and the latter is short-circuited, by measuring the values la and I b of the current at the start and at the end of each of the interruption periods, the quantities R, T 1 and r being known.

Pratiquemment, il n'est pas nécessaire de mesurer la tension Ui elle-même et de la comparer avec une tension de seuil Uis pour déterminer l'instant ti. Il suffit, par exemple, de déterminer la valeur du terme

Figure imgb0007
de l'équation (3) ci-dessus et de comparer cette valeur avec une valeur de référence
Figure imgb0008
 In practice, it is not necessary to measure the voltage U i itself and to compare it with a threshold voltage U is to determine the instant t i . It is enough, for example, to determine the value of the term
Figure imgb0007
 from equation (3) above and compare this value with a reference value
Figure imgb0008

La détermination de la valeur du terme

Figure imgb0009
peut se faire en mesurant et en mettant en mémoire la valeur du courant la au début de la période de mesure, en multipliant la valeur mesurée et mémorisée par une constante
Figure imgb0010
qui est connue puisque T et T 1 sont connus, en mesurant le courant Ib à la fin de la période de mesure, et en calculant la différence (α . la - Ib).Determining the value of the term
Figure imgb0009
 can be done by measuring and storing the value of the current la at the start of the measurement period, by multiplying the measured and stored value by a constant
Figure imgb0010
 which is known since T and T 1 are known, by measuring the current I b at the end of the measurement period, and by calculating the difference (α. la - I b ).

Cette différence est ensuite comparéer à la valeur β, et un signal est produit lorsque cette comparaison montre que (a. la- Ib) ≥β. Ce signal indique que la tension Ui est devenue égale ou supérieure à la tension de seuil Uis, et donc que l'instant t, a été atteint ou dépassé.This difference is then compared to the value β, and a signal is produced when this comparison shows that (a. La- I b ) ≥β. This signal indicates that the voltage U i has become equal to or greater than the threshold voltage U is , and therefore that the instant t, has been reached or exceeded.

Pour déterminer l'instant t1, il est également possible de mesurer le courant Ia et de calculer le produit α · la comme ci-dessus, de calculer la différence (a. la-β), de mesurer le courant Ib circulant dans l'enroulement à la fin de la période d'interruption, et de comparer ce courant Ib à la différence (α · la-β). Lorsque le courant Ibest égal ou inférieur à cette différence (α. la-β, la tension U, est égale ou supérieure à la tension de référence Uis.To determine the instant t 1 , it is also possible to measure the current I a and to calculate the product α · la as above, calculate the difference (a. la-β), measure the current I b flowing in the winding at the end of the interruption period, and compare this current I b to the difference (α · la-β). When the current I b is equal to or less than this difference (α. La-β, the voltage U, is equal to or greater than the reference voltage U is .

Il faut noter que les considérations faites ci-dessus restent valables si les calculs et les comparaisons sont faits en utilisant, à la place de la valeur des courants Ia et Ib, la valeur de deux courants I'a et I'b mesurés au début et à la fin d'une période de mesure ayant une durée T 1 ' inférieure à T 1, et si, bien entendu, la valeur T 1 est remplacée par cette valeur T 1It should be noted that the considerations made above remain valid if the calculations and comparisons are made using, instead of the value of the currents I a and I b , the value of two currents I ' a and I' b measured at the start and at the end of a measurement period having a duration T 1 'less than T 1, and if, of course, the value T 1 is replaced by this value T 1

Il n'est pas nécessaire d'attendre la fin de la période d'interruption ou de mesure pour faire les différents calculs et comparaisons ci-dessus. Il est possible de mesurer en permanence le courant i qui circule dans l'entroulement après le début de la période d'interruption ou de mesure et d'utiliser la valeur de ce courant, à la place du courant 1 b, pour faire ces calculs et ces comparaisons, également en permanence.It is not necessary to wait for the end of the interruption or measurement period to make the various calculations and comparisons above. It is possible to permanently measure the current i flowing in the flow after the start of the interruption or measurement period and to use the value of this current, instead of current 1 b , to make these calculations. and these comparisons, also continuously.

Dans les exemple qui vont être décrits ci-dessous, les divers courants la, Ib et i sont mesurés par la valeur des tensions Ua, Ubet u qu'ils produisent respectivement en passant dans une résistance de mesure branchée en série avec l'enroulement du moteur pendant les périodes d'interruption de l'impulsion motrice. Il est évident que les différents calculs décrits ci-dessus sont alors effectués sur les tensions qui représentent ces courants et qui leurs sont proportionnelles. Le facteur β est alors remplacé par un facteur

Figure imgb0011
où Rm est la valeur de la résistance de mesure.In the examples which will be described below, the various currents la, I b and i are measured by the value of the voltages U a , Ubet u which they produce respectively by passing through a measurement resistor connected in series with the motor winding during periods of interruption of the driving pulse. It is obvious that the various calculations described above are then carried out on the voltages which represent these currents and which are proportional to them. The factor β is then replaced by a factor
Figure imgb0011
 where R m is the value of the measurement resistance.

L'équation (3) ci-dessus devient dans ces conditions:

Figure imgb0012
Equation (3) above becomes under these conditions:
Figure imgb0012

La pièce d'horlogerie représentée à titre d'exemple par la figure 2 comprend un circuit 8 générateur d'un signal de standard de temps H, ayant une fréquence égale, par exemple, à 16'384 Hz. Le circuit 8 est formé d'un oscillateur à quartz et d'un premier étage diviseur par deux, et sa sortie est reliée à l'entrée d'un circuit diviseur 9 élaborant, à partir du signal de standard de temps H divers signaux périodiques comprenant notamment un signal I de fréquence égale à 1/2 Hz, un signal J de fréquence égale à 1 Hz et un signal K de fréquence égale à 64 Hz.The timepiece shown by way of example in FIG. 2 comprises a circuit 8 generating a time standard signal H, having a frequency equal, for example, to 16,384 Hz. The circuit 8 is formed by a quartz oscillator and a first divider by two stage, and its output is connected to the input of a divider circuit 9 developing, from the time standard signal H various periodic signals including in particular a signal I of frequency equal to 1/2 Hz, a signal J of frequency equal to 1 Hz and a signal K of frequency equal to 64 Hz.

La pièce d'horlogerie de la figure 2 comporte en outre un circuit formateur d'impulsions 15 dont la sortie délivre un signal, désigné par Z, formé d'une suite d'impulsions qui passent à l'état 1« chaque fois que le signal J passe lui-même à l'état »1«, c'est-à-dire chaque seconde (voir la figure 2a). Les impulsions du signal Z repassent à l'état »0« en réponse à un signal N délivré par un circuit de calcul 26 qui sera décrit plus loin. L'instant où ce signal N apparaît détermine donc la durée des impulsions du signal Z.The timepiece of FIG. 2 further comprises a pulse-forming circuit 15, the output of which delivers a signal, designated by Z, formed by a series of pulses which pass to state 1 "each time the signal J itself goes to state "1", that is to say every second (see FIG. 2a). The pulses of signal Z return to the state »0« in response to a signal N delivered by a calculation circuit 26 which will be described later. The instant when this signal N appears therefore determines the duration of the pulses of the signal Z.

Le circuit formateur d'impulsions 15 délivre également un signal auxiliaire désigné par 0 formé d'impulsions qui passent à l'état >1 « en même temps que les impulsions Z mais qui ont une durée fixe de, parexemple, 7,8 millisecondes.The pulse forming circuit 15 also delivers an auxiliary signal designated by 0 formed by pulses which pass to the state> 1 "at the same time as the Z pulses but which have a fixed duration of, for example, 7.8 milliseconds.

Chaque fois que le signal Z est à l'état »1 «, un circuit d'entraînement 12 délivre une impulsion motrice à l'enroulement 11 a du moteur 11. La tension mesurée aux bornes de cet enroulement 11 a est désignée par Um à la figure 2 a. L'énergie à l'enroulement 11 a pendant chaque impulsion motrice est délivrée par une source d'alimentation 10.Each time the signal Z is in the state "1", a drive circuit 12 delivers a driving pulse to the winding 11 a of the motor 11. The voltage measured at the terminals of this winding 11 a is designated by U m in Figure 2 a. The energy at the winding 11 a during each driving pulse is delivered by a power source 10.

La polarité des impulsions motrices est déterminée par l'état logique du signal I, qui prend alternativement l'état »0« et l'état » 1« pendant 1 seconde.The polarity of the driving pulses is determined by the logic state of the signal I, which alternately takes the state »0« and the state »1« for 1 second.

Le circuit d'entraînement 12 est en outre agencé de manière que les impulsions motrice soient hachées en réponse à un signal M formé d'impulsions ayant une fréquence élevée. Chaque fois que 1 signal M est à l'état » 1«, par exemple, le circuit d'entraînement 12 interrompt la liaison entre la source d'alimentation 10 et l'enroulement 11 a, et met ce dernier en court-circuit. Pendant ces périodes d'interruption, le circuit 12 délivre sur une sortie 12 a une tension proportionnelle au courant qui circule dans l'enroulement 11 a. Cette tension est utilisée par un circuit de mesure 16, dont un exemple sera décrit plus loin, pour déterminer l'instant t, où la tension U, induite dans l'enroulement 11 a par la rotation du rotor atteint la valeur de référence Uis.The drive circuit 12 is further arranged so that the driving pulses are chopped in response to a signal M formed of pulses having a high frequency. Each time 1 signal M is in the state "1", for example, the drive circuit 12 interrupts the connection between the power source 10 and the winding 11 a, and puts the latter in short-circuit. During these periods of interruption, the circuit 12 delivers on an output 12 a voltage proportional to the current which circulates in the winding 11 a. This voltage is used by a measurement circuit 16, an example of which will be described later, to determine the instant t, where the voltage U, induced in the winding 11 a by the rotation of the rotor reaches the reference value U is .

A l'instant t1, ce circuit de mesure 16 délivre à sa sortie 16 e un signal P, qui est à son tour utilisé par le circuit de calcul 26 pour fournir le signal N à un instant t2. Ce circuit de calcul 26, dont un exemple sera décrit plus loin, est agencé de manière que l'instant t2 soit séparé du début de l'impulsion motrice par un temps égal à (λ . Td + Δ), où À et Δ sont les constantes déterminées expérimentalement mentionnées ci-dessus. Ce temps est donc égal à la durée optimale de l'impulsion motrice. Comme le signal N fait repasser le signal Z à l'état »0«, ce signal Z, et donc l'impulsion motrice, ont une durée égale à cette durée optimale.At time t 1 , this measurement circuit 16 delivers at its output 16 e a signal P, which is in turn used by the calculation circuit 26 to supply the signal N at time t 2 . This calculation circuit 26, an example of which will be described later, is arranged so that the instant t 2 is separated from the start of the driving pulse by a time equal to (λ. T d + Δ), where À and Δ are the experimentally determined constants mentioned above. This time is therefore equal to the optimal duration of the motor pulse. As the signal N returns the signal Z to the state "0", this signal Z, and therefore the driving pulse, have a duration equal to this optimal duration.

Le signal M est fourni par un circuit 13, dont un exemple sera décrit plus loin. La durée de chaque impulsion de ce signal M et la durée du laps de temps qui sépare ces impulsions sont déterminées par le contenu d'une mémoire 14.The signal M is supplied by a circuit 13, an example of which will be described later. The duration of each pulse of this signal M and the duration of the period of time which separates these pulses are determined by the content of a memory 14.

La figure 3 représente le schéma d'un exemple d'une première forme d'exécution 16 de la tension induite Ui du dispositif représenté la figure 2. Ce circuit 16 comprend une entrée 16 a qui reçoit du circuit 12 la tension proportionnelle au courant circulant dans l'enroulement 11 a, un condensateur 18 dont une armature est reliée à la masse 19 et dont l'autre armature 18 a est reliée à l'entrée 16 a par une porte de transmission 20 ainsi qu'à l'entrée non-inverseuse d'un amplificateur opérationnel 21 dont la sortie est reliée directement à son entrée inverseuse. L'électrode de commande de la porte 20 est reliée à la sortie Q d'une bascule de type T 22 dont l'entrée d'horloge T reçoit le signal M par l'intermédiaire de l'entrée 16 c et dont l'entrée de remise à zéro R reçoit le signal H par l'intermédiaire de l'entrée 16d.FIG. 3 represents the diagram of an example of a first embodiment 16 of the induced voltage U i of the device represented in FIG. 2. This circuit 16 comprises an input 16 a which receives from circuit 12 the voltage proportional to the current circulating in the winding 11 a, a capacitor 18, one armature of which is connected to ground 19 and the other armature 18 of which is connected to the input 16 a by a transmission gate 20 as well as to the non-inverting input of an operational amplifier 21 whose output is connected directly to its inverting input. The control electrode of the gate 20 is connected to the output Q of a flip-flop of type T 22 whose clock input T receives the signal M via the input 16 c and whose input reset R receives signal H via input 16d.

Un circuit de calcul 23 comporte un diviseur de tension formé de deux résistances 231 et 232 branchées en série entre la sortie de l'amplificateur 21 et la masse, et un amplificateur différentiel 233 dont l'entrée non-inverseuse est reliée au point de liaison des résistances 231 et 232. Le circuit 23 comporte en outre deux résistances 234 et 235 branchées en série entre la sortie de l'amplificateur 233 et un générateur de tension 24. L'entrée inverseuse de l'amplificateur 233 est reliée au point de liaison des résistances 234 et 235.A calculation circuit 23 comprises a voltage divider formed by two resistors 231 and 232 connected in series between the output of the amplifier 21 and the ground, and a differential amplifier 233 whose non-inverting input is connected to the connection point resistors 231 and 232. The circuit 23 further comprises two resistors 234 and 235 connected in series between the output of the amplifier 233 and a voltage generator 24. The inverting input of the amplifier 233 is connected to the connection point resistors 234 and 235.

La sortie de l'amplificateur 233 est reliée à l'entrée noninverseuse d'un autre amplificateur différentiel 25 dont l'entrée inverseuse est reliée à la borne 16 a par l'intermédiaire d'une porte de transmission 20a. L'électrode de commande de cette porte 20 a est reliée à la sortie Q d'une bascule 22 a de type T dont l'entrée d'horloge T reçoit le signal M par l'intermédiaire d'un inverseur 22 b dont l'entrée R reçoit le signal H. La sortie de l'amplificateur 25 constitue la sortie 16 e du circuit de mesure 16.The output of amplifier 233 is connected to the non-inverting input of another differential amplifier 25, the inverting input of which is connected to terminal 16a via a transmission gate 20a. The control electrode of this gate 20 a is connected to the output Q of a flip-flop 22 a of type T, the clock input T of which receives the signal M via an inverter 22 b, the input R receives the signal H. The output of the amplifier 25 constitutes the output 16 e of the measurement circuit 16.

Le fonctionnement du circuit de la figure 3 est le suivant: au moment du passage à l'état »1 du signal M, au début de chaque période d'interruption, la sortie Q de la bascule 22 passe à l'état »1 «, ce qui entraîne l'ouverture de la porte 20. Lorsque le signal H passe également à l'état »1 «, environ 30 microsecondes plus tard, la sortie Q de la bascule 22 repasse à l'état »0«, et la porte 20 se bloque à nouveau. Pendant que la 20 est ouverte, le condensateur 18 se charge à une tension Ua proportionnelle au courant la qui circule dans l'enroulement 11 à cet instant. Cette tension Ua est appliquée, par l'intermédiaire de l'amplificateur 21, au diviseur de tension formé par les résistances 231 et 232. Les valeurs de ces résistances sont choisies de manière que la tension appliquée à l'entrée non-inverseuse de l'amplificateur 233 soit égale à α. Ua, où a est égal à

Figure imgb0013
comme ci-dessus, c'est-à-dire qu'elle soit proportionnelle à α · la.The operation of the circuit of FIG. 3 is as follows: at the time of the transition to the state "1 of the signal M, at the start of each interruption period, the output Q of the flip-flop 22 changes to the state" 1 " , which causes the door 20 to open. When the signal H also changes to state "1", about 30 microseconds later, the output Q of flip-flop 22 returns to state "0", and the door 20 hangs again. While the 20 is open, the capacitor 18 charges at a voltage U a proportional to the current la which flows in the winding 11 at this instant. This voltage U a is applied, via the amplifier 21, to the voltage divider formed by the resistors 231 and 232. The values of these resistors are chosen so that the voltage applied to the non-inverting input of the amplifier 233 is equal to α. U a , where a is equal to
Figure imgb0013
 as above, that is to say that it is proportional to α · la.

Les résistances 234 et 235, ainsi que la tension fournie par le générateur 24 sont choisies de manière que la sortie de l'amplificateur 233 délivre une tension égale à (α · Ua - β'), où

Figure imgb0014
comme ci-dessus.The resistors 234 and 235, as well as the voltage supplied by the generator 24 are chosen so that the output of the amplifier 233 delivers a voltage equal to (α · Ua - β '), where
Figure imgb0014
 as above.

A la fin de la période d'interruption, le signal M passe à l'état »0«, et sortie Q de la bascule 22 a passe à l'état »1 pendant environ 30 microsecondes. La tension Ub proportionnelle au courant Ib qui circule dans l'enroulement 11 a à cet instant est donc appliquée à l'entrée inverseuse de l'amplificateur 25 qui la compare à la tension (α · Ua - β') présente à la sortie de l'amplificateur 233. Tant que cette tension Ub est supérieure à cette tension (α · Ua -β'), la sortie de l'amplificateur 25 reste à l'état »0«. Si la tension Ub est inférieure à cette tension (a. Ua-β'), la sortie de l'amplificateur 25 délivre le signal P en passant à l'état »1 «, ce qui indique que la tension Ui induite dans l'enroulement par la rotation du rotor a dépassé la tension de seuil Uis. Ce passage de la sortie de l'amplificateur 25 à l'état» « marque l'instant t1.At the end of the interruption period, the signal M goes to the state "0", and output Q of the flip-flop 22 a goes to the state "1 for about 30 microseconds. The voltage U b proportional to the current I b which flows in the winding 11 a at this instant is therefore applied to the inverting input of the amplifier 25 which compares it to the voltage (α · Ua - β ') present at the output of amplifier 233. As long as this voltage U b is greater than this voltage (α · Ua -β '), the output of amplifier 25 remains in the state »0«. If the voltage U b is less than this voltage (a. U a -β '), the output of the amplifier 25 delivers the signal P while passing to the state "1", which indicates that the voltage U i induced in the winding by the rotation of the rotor has exceeded the threshold voltage U is . This passage of the output of the amplifier 25 to the state "" marks the instant t 1 .

La figure 3 a représente le schéma d'une deuxième forme d'exécution du circuit 16 de mesure de la tension induite Ui. Les éléments 18, 20, 20 a, 21, 22, 22 a, 22 b, 24, 231 et 232 de ce circuit sont identiques aux éléments désignés par les mêmes références à la figure 3 et fonctionnent de la même manière.FIG. 3 a represents the diagram of a second embodiment of the circuit 16 for measuring the induced voltage U i . The elements 18, 20, 20 a, 21, 22, 22 a, 22 b, 24, 231 and 232 of this circuit are identical to the elements designated by the same references in Figure 3 and operate in the same way.

Le signal α . Ua présent au point de liaison des résistances 231 et 232 est appliqué à l'entrée non-inverseuse d'un amplificateur 233'. Deux résistances 234' et 235' sont reliées en série entre la porte 20 a et la sortie de l'amplificateur 233'. Le point de liaison de ces deux résistances est relié à l'entrée inverseuse de l'amplificateur 233'. La sortie de l'amplificateur 233' est reliée à l'entrée non-inverseuse d'un amplificateur 25' dont l'entrée inverseuse est reliée à la sortie du générateur de tension 24. La sortie de l'amplificateur 25' constitue dans ce cas la sortie 16 e du circuit de mesure 16.The signal α. U is present at the connection point of the resistors 231 and 232 is applied to the non-inverting input of an amplifier 233 '. Two resistors 234 'and 235' are connected in series between the gate 20 a and the output of the amplifier 233 '. The connection point of these two resistors is connected to the inverting input of the amplifier 233 '. The output of the amplifier 233 'is connected to the non-inverting input of an amplifier 25' whose inverting input is connected to the output of the voltage generator 24. The output of the amplifier 25 'constitutes in this case the output 16 e of the measurement circuit 16.

Les résistance 234' et 235' sont choisies de manière que la sortie de l'amplificateur 233' délivre une tension égale à (α. Ua- Ub). L'amplificateur 25' compare cette tension à la tension β' fournie par le générateur 24. La sortie de l'amplificateur 25' fournit le signal P en passant à l'état »1 1 lorsque la tension (α· Ua - Ub) devient supérieure à la tension β', c'est-à-dire à nouveau lorsque la tension Ui induite dans l'enroulement par la rotation du rotor devient supérieure à la tension de seuil Uis.The resistors 234 'and 235' are chosen so that the output of the amplifier 233 'delivers a voltage equal to (α. U a - U b ). The amplifier 25 'compares this voltage to the voltage β' supplied by the generator 24. The output of the amplifier 25 'supplies the signal P passing to the state' 1 1 when the voltage (α · U a - U b ) becomes greater than the voltage β ', that is to say again when the voltage U i induced in the winding by the rotation of the rotor becomes greater than the threshold voltage U is .

Comme cela a déjà été noté plus haut, il n'est pas nécessaire d'attendre la fin de la période d'interruption pour faire les différents calculs et comparaisons décrits ci-dessus. La porte 20 a, la bascule 22 a et l'inverseur 22 b peuvent être supprimés des schémas des figures 3 et 3 a, l'entrée 16 a du circuit 16 étant alors reliée directement à l'entrée inverseuse de l'amplificateur 25, respectivement à la résistance 235'. Dans ce cas, les calculs et comparaisons sont donc effectués en permanence sur la tension u produite dans la résistance de mesure par le courant i qui circule dans l'enroulement 11 a après le début de la période d'interruption. Le signal P est alors délivré dès que la tension un devient inférieure à la tension (α · Ua - β'), respectivement dès que la tension (a. Ua - u) devient supérieure à la tension β'.As already noted above, it is not necessary to wait for the end of the interruption period to make the various calculations and comparisons described above. The door 20 a, the flip-flop 22 a and the inverter 22 b can be deleted from the diagrams of FIGS. 3 and 3 a, the input 16 a of the circuit 16 then being connected directly to the inverting input of the amplifier 25, respectively at resistance 235 '. In this case, the calculations and comparisons are therefore made continuously on the voltage u produced in the measurement resistor by the current i which flows in the winding 11 a after the start of the interruption period. The signal P is then delivered as soon as the voltage one becomes lower than the voltage (α · U a - β '), respectively as soon as the voltage (a. Ua - u) becomes higher than the voltage β'.

La figure 4 représente un exemple de réalisation du circuit calculateur 26 de la figure 2. Dans cet exemple, le circuit 26 comprend un compteur réversible à présélection 27 ayant des bornes de présélection P1, P2, P3 et P4 reliées respectivement aux bornes de sortie M 1, M 2, M 3 et M 4 d'une mémoire morte 28. Le compteur 27 comporte une entrée de commande de présélection PE recevant le signal O par l'intermédiaire d'un inverseur 29. L'entrée d'horloge CL du compteur 27 est reliée à la sortie d'une porte NON-ET 30 ayant deux entrées reliées chacune à la sortie d'une porte NON-ET 31, respectivement 32. Le circuit 26 comporte en outre un circuit diviseur 33 fournissant deux signaux Q1 et Q2 de fréquences respectives f 1 et f 2, en réponse au signal H. Le signal Q est appliqué sur l'une des entrées de la porte 31 tandis que le signal Q2 est appliqué sur l'une des entrées de la porte 32. Une deuxième entrée de la porte 31 est reliée à la sortie Q d'une bascule de type T 34 dont l'entrée d'horloge T est reliée à la borne d'entrée 26 a du circuit 26. Une deuxième entrée de la porte 32 est reliée à la sortie Q de la bascule 34. L'entrée de commande de sens de comptage U/D du compteur 27 est reliée à la sortie 0 de la bascule 34.FIG. 4 represents an exemplary embodiment of the computer circuit 26 of FIG. 2. In this example, the circuit 26 comprises a reversible preselection counter 27 having preselection terminals P1, P2, P3 and P4 connected respectively to the output terminals M 1, M 2, M 3 and M 4 of a read-only memory 28. The counter 27 includes a preselection control input PE receiving the signal O via an inverter 29. The clock input CL of the counter 27 is connected to the output of a NAND gate 30 having two inputs each connected to the output of a NAND gate 31, respectively 32. The circuit 26 further comprises a divider circuit 33 providing two signals Q1 and Q2 of respective frequencies f 1 and f 2, in response to the signal H. The signal Q is applied to one of the inputs of door 31 while the signal Q2 is applied to one of the inputs of door 32. A second input of gate 31 is connected to output Q of a T-type flip-flop whose input of clock T is connected to the input terminal 26 a of the circuit 26. A second input of the gate 32 is connected to the output Q of the flip-flop 34. The counting direction control input U / D of the counter 27 is connected to output 0 of flip-flop 34.

Le compteur 27 comporte également une sortie de coïncidence C dont l'état passe à »1« pendant un court instant lorsque le contenu du compteur atteint la valeur zéro. Cette sortie C est reliée à l'entrée d'horloge T d'une bascule de type T 35 dont la sortie Q constitue la sortie 26 b du circuit 26, et dont l'entrée de remise à zéro R est reliée à la sortie Q d'une bascule de type T 101. Cette dernière bascule reçoit le signal 0 sur son entrée d'horloge T et le signal H sur son entrée de remise à zéro R. La sortie C du compteur 27 est également reliée à l'entrée de remise à zéro R de la bascule 34.The counter 27 also has a coincidence output C whose state changes to »1« for a short time when the content of the counter reaches the value zero. This output C is connected to the clock input T of a flip-flop of type T 35 whose output Q constitutes the output 26 b of circuit 26, and whose reset input R is connected to the output Q of a type T flip-flop 101. This latter flip-flop receives the signal 0 on its clock input T and the signal H on its reset input R. The output C of the counter 27 is also connected to the input of reset R of flip-flop 34.

La figure 4 a illustre le fonctionnement du circuit 26 représenté à la figure 4.FIG. 4 a illustrates the operation of the circuit 26 shown in FIG. 4.

Entre les impulsions motrices, le signal 0 est à l'état »0«, et l'entrée PE du compteur 27 est à l'état »1 «. Ce compteur 27 est donc bloqué dans l'état où son contenu correspond au contenu de la mémoire 28, qui est désigné par No. Au temps to coïncidant avec le début d'une impulsion motrice, le signal 0 passe à »1 «, mettant à l'état »0« l'entrée PE du compteur 27 qui est ainsi libéré et commence à compter en sens normal les impulsions issues de la porte 30, à partir de cet état No. Ce comptage est effectué à la fréquence fl. A l'instant t, où la tension U, atteint la valeur Uis, l'entrée 26 a passe à »1 «, et les sorties Q et Q de la bascule 34 passent respectivement l'état »1 « et à l'état »0«. L'état de l'entrée de commande U/D du compteur 27 passe à »0«. A partir de cet instant, le compteur 27 fonctionne en décomp- teur. Le décomptage est effectué à la fréquence f2. A l'instant t2 où le contenu du compteur 27 devient égal à zéro, sa sortie C passe à l'état »1 « pendant un court instant, mettant à l'état »1 « la bascule 35 dont la sortie Q, qui était précédemment à l'état »0«, passe à l'état » 1 «.Between the driving pulses, the signal 0 is in the state "0", and the input PE of the counter 27 is in the state "1". This counter 27 is therefore blocked in the state where its content corresponds to the content of the memory 28, which is designated by No. At the time t o coinciding with the start of a driving pulse, the signal 0 goes to "1", putting in the state “0” the input PE of the counter 27 which is thus released and begins to count in the normal direction the pulses coming from the gate 30, from this state No. This counting is carried out at the frequency fl. At time t, when the voltage U, reaches the value U is , the input 26 a passes to »1«, and the outputs Q and Q of the flip-flop 34 respectively pass the state »1« and to the state »0«. The status of the U / D control input of counter 27 changes to »0«. From this moment, the counter 27 operates as a counter. The countdown is carried out at the frequency f2. At the instant t 2 when the content of the counter 27 becomes equal to zero, its output C goes to the state "1" for a short time, putting to the state "1" the flip-flop 35 including the output Q, which was previously in state "0", goes to state "1".

Simultanément, les sorties Q et Q de la bascule 34 repassent à l'état »0«, respectivement 1 «. A la fin de l'impulsion, l'entrée PE du compteur 27 repasse à l'état »1 «. Le contenu de ce compteur 27 reprend donc la valeur fixée dans la mémoire 28 et reste à cette valeur jusqu'à ce que le signal 0 repasse à l'état »1 «.Simultaneously, the Q and Q of the flip-flop 34 return to the state "0", respectively 1 ". At the end of the pulse, the PE input of the counter 27 returns to the state "1". The content of this counter 27 therefore takes up the value fixed in the memory 28 and remains at this value until the signal 0 returns to the state »1«.

La sortie Q de la bascule 35 est remise à l'état »0« au début de chaque impulsion motrice par l'état »1 « qui apparaît à la sortie Q de la bascule 101 en réponse au signal 0. Cet état »1 « est supprimé après environ 30 microsecondes, lorsque le signal H passe à l'état »1 «.The output Q of the flip-flop 35 is reset to the state "0" at the start of each driving pulse by the state "1" which appears at the output Q of the flip-flop 101 in response to the signal 0. This state "1" is deleted after approximately 30 microseconds, when signal H changes to state »1«.

La figure 4 a montre que le temps T qui s'écoule le début to de l'impulsion motrice et l'apparition, à l'instant t2 du signal N à la sortie 26 b du circuit 26 est lié au temps Td qui s'écoule entre les instants to et t, par la relation:

Figure imgb0015
dans laquelle f 1 et f 2 sont les fréquences des signaux fournis par les sorties Q 1 et Q2 du diviseur 33 et No est le nombre contenu dans la mémoire 28, et donc le nombre contenu par le compteur 27 à l'instant to.FIG. 4 a shows that the time T which elapses the start t o of the driving pulse and the appearance, at time t 2 of the signal N at the output 26 b of the circuit 26 is linked to the time T d which flows between the instants t o and t, by the relation:
Figure imgb0015
 in which f 1 and f 2 are the frequencies of the signals supplied by the outputs Q 1 and Q2 of the divider 33 and No is the number contained in the memory 28, and therefore the number contained by the counter 27 at time t o .

La comparaison de cette équation avec l'équaion Topt = λTd + mentionnée plus haut, où λ et Δ sont des constantes déterminées expérimentalement pour chaque type de moteur, permet de choisir les valeurs de f 1, f 2 et No de manière que ce temps T qui s'écoule entre le début de l'impulsion motrice et l'apparition du signal N soit toujours égal à la durée optimal Topt de l'impulsion motrice.The comparison of this equation with the equation T opt = λT d + mentioned above, where λ and Δ are constants determined experimentally for each type of motor, makes it possible to choose the values of f 1, f 2 and No so that this time T which elapses between the start of the driving pulse and the appearance of the signal N is always equal to the optimal duration T opt of the driving pulse.

La figure 5 représente un exemple de schéma des circuits 12 et 15 de la figure 2. Le circuit 15 est formé dans cet exemple de deux bascules de type T dont les entrées d'horloge T reçoivent toutes deux le signal J délivré par le diviseur de fréquence 9 de la figure 2 à une fréquence de 1 Hz. L'entrée R de remise à zéro de la bascule 38 reçoit le signal K, également fourni par le diviseur de fréquence 9, à une fréquence de 64 Hz. La sortie Q de cette bascule 38 passe donc à l'état »1« chaque seconde au moment où le signal J passe à l'état »1 «, et repasse à l'état »0« environ 7,8 millisecondes plus tard, lorsque le signal K passe à son tour à l'état »1 «. Cette sortie Q de la bascule 38 fournit donc le signal 0.FIG. 5 represents an exemplary diagram of the circuits 12 and 15 of FIG. 2. The circuit 15 is formed in this example of two flip-flops of type T whose clock inputs T both receive the signal J delivered by the divider of frequency 9 of FIG. 2 at a frequency of 1 Hz. The reset input R of flip-flop 38 receives the signal K, also supplied by the frequency divider 9, at a frequency of 64 Hz. The output Q of this flip-flop 38 therefore goes to state »1« every second when the signal J goes to state »1«, and goes back to state »0« about 7.8 milliseconds later, when signal K in turn goes to state "1". This output Q of flip-flop 38 therefore supplies the signal 0.

L'entrée R de remise à zéro de la bascule 39 reçoit le signal N du circuit de calcul 26 de la figure 2. La sortie Q de cette bascule 39 passe donc également à état »1 lorsque le signal J passe à l'état »1 «, et repasse à l'état »0« lorsque le circuit 26 délivre le signal N à l'instant t2 déterminé de la manière décrite ci-dessus. Cette sortie Q de la bascule 39 fournit donc le signal Z qui a une durée égale à la durée optimum de l'impulsion motrice.The reset input R of the flip-flop 39 receives the signal N from the calculation circuit 26 of FIG. 2. The output Q of this flip-flop 39 therefore also goes to state "1 when the signal J goes to the state" 1 ", and returns to the state" 0 "when the circuit 26 delivers the signal N at the instant t 2 determined in the manner described above. This output Q of the flip-flop 39 therefore supplies the signal Z which has a duration equal to the optimum duration of the driving pulse.

Le circuit 12 de la figure 2 comporte, dans cet exemple, un circuit combinatoire 43 formé de quatre portes ET 431 à 434, de deux portes OU 435 et 436 et de deux inverseurs 437 et 438. L'enroulement 11 a du moteur est branché dans un circuit formé de quatre portes de transmission 44 à 47 connectées de manière classique entre la borne + V de la source d'alimentation 10 et la masse.The circuit 12 of FIG. 2 comprises, in this example, a combinatorial circuit 43 formed by four AND gates 431 to 434, two OR gates 435 and 436 and two inverters 437 and 438. The winding 11a of the motor is connected in a circuit formed by four transmission doors 44 to 47 conventionally connected between the + V terminal of the power source 10 and the ground.

Deux autres portes de transmission 48 et 49 relient chacune une des bornes de l'enroulement 11 a à une première borne d'une résistance 17 dont la deuxième borne est reliée à la masse. La première borne de cette résistance 17 est également reliée à l'entrée 16 a du circuit 16 de la figure 2. Cette résistance 17 constitue la résistance de mesure mentionnée précédemment.Two other transmission doors 48 and 49 each connect one of the terminals of the winding 11 a to a first terminal of a resistor 17, the second terminal of which is connected to ground. The first terminal of this resistor 17 is also connected to the input 16 a of the circuit 16 of FIG. 2. This resistor 17 constitutes the measurement resistance mentioned previously.

Les électrodes de commande des portes 44 à 49 sont reliées aux sorties du circuit combinatoire 43 dont les entrées reçoivent respectivement les signaux I, Z et M. Ce circuit combinatoire ne sera pas décrit plus en détail, car il est facile de voir, à l'aide de la figure 5 a, que:

  • - lorsque que le signal Z est à l'état »0«, c'est-à-dire entre les impulsions motrices, les électrodes de commande des portes 44 à 49 sont toutes à l'état »0«, quel que soit l'état des signaux I et M. Ces portes 44 à 49 sont donc bloquées, et l'enroulement 11 a est séparé de la source d'alimentation;
  • - lorsque le signal Z est à l'état »1 «, c'est-à-dire pendant les impulsions motrices, et que le signal M est à l'état »0«, les portes 44 et 46 sont conductrices si le signal 1 est à l'état »0«, toutes les autres portes étant bloquées, et les portes 45 et 47 sont conductrices si le signal 1 est à l'état »1 «, toutes les autres portes étant alors également bloquées. La source d'alimentation est donc reliée à l'enroulement 11 a par l'intermédiaire des portes 44 et 46 ou 45 et 47, et un courant circule dans l'enroulement 11 a dans le sens de la flèche 11 b ou dans le sens inverse. Cette situation est celle qui se présente entre les périodes d'interruption, pendant les impulsions élémentaires; et
  • - lorsque le signal Z est à l'état »1 « et que le signal M est également à l'état »1 «, les portes 47 et 48 ou 46 et 49 sont conductrices, selon l'état »0« ou »1 « du signal I, toutes les autres portes étant alors bloquées. La source d'alimentation est donc déconnectée de l'enroulement 11 a, et le courant qui passe dans cet enroulement 11 a passe également dans la résistance 17 dans laquelle il crée la tension appliquée à l'entrée 16 a du circuit de mesure 16. Cette situation est celle qui se présente pendant les périodes d'interruption de l'impulsion motrice.
The control electrodes of the doors 44 to 49 are connected to the outputs of the combinational circuit 43 whose inputs receive the signals I, Z and M respectively. This combinative circuit will not be described in more detail, because it is easy to see, at the using FIG. 5 a, that:
  • - when the signal Z is in the state "0", that is to say between the driving pulses, the control electrodes of the doors 44 to 49 are all in the state "0", whatever the 'state of signals I and M. These doors 44 to 49 are therefore blocked, and the winding 11 a is separated from the power source;
  • - when the signal Z is in the state »1«, that is to say during the driving pulses, and that the signal M is in the state »0«, the gates 44 and 46 are conductive if the signal 1 is in the state "0", all the other doors being blocked, and the doors 45 and 47 are conducting if the signal 1 is in the state "1", all the other doors then being also blocked. The power source is therefore connected to the winding 11 a via the doors 44 and 46 or 45 and 47, and a current flows in the winding 11 a in the direction of the arrow 11 b or in the direction reverse. This situation is that which occurs between periods of interruption, during elementary impulses; and
  • - when signal Z is in state »1« and signal M is also in state »1«, doors 47 and 48 or 46 and 49 are conductive, depending on state »0« or »1 “Of signal I, all the other doors then being blocked. The power source is therefore disconnected from the winding 11 a, and the current which passes through this winding 11 a also passes through the resistor 17 in which it creates the voltage applied to the input 16 a of the measurement circuit 16. This situation is that which occurs during periods of interruption of the motor impulse.

La figure 6 représente à titre d'exemple le schéma d'une forme d'éxécution des circuits 13 et 14 du dispositif de la figure 2.FIG. 6 shows by way of example the diagram of an embodiment of the circuits 13 and 14 of the device of FIG. 2.

Le circuit 13 comporte deux compteurs réversibles à présélection 131 et 132. Les entrées U/D de commande de sens de comptage de ces compteurs 131 et 132 sont en permanence à l'état »1 «. Ces compteurs 131 et 132 fonctionnent donc en décompteurs. Leurs bornes de présélection, désignées ensemble par Pi, sont respectivement reliées aux sorties, désignées ensemble par Si, de deux mémoires 141 et 142 qui forment la mémoire 14 du circuit de la figure 2. Ces mémoires 141 et 142 peuvent être, par exemple, des mémoires mortes.The circuit 13 includes two reversible preselection counters 131 and 132. The U / D inputs for controlling the counting direction of these counters 131 and 132 are permanently in the "1" state. These counters 131 and 132 therefore operate as down counters. Their preselection terminals, designated together by Pi, are respectively connected to the outputs, designated together by Si, of two memories 141 and 142 which form the memory 14 of the circuit of FIG. 2. These memories 141 and 142 can be, for example, dead memories.

Les entrées d'horloge CL des compteurs 131 et 132 sont toutes deux reliées à la sortie du générateur 8 (figure 2) qui délivre le signal H.The clock inputs CL of the counters 131 and 132 are both connected to the output of the generator 8 (FIG. 2) which delivers the signal H.

Les compteurs 131 et 132 comportent chacun une sortie de coïncidence C qui délivre une courte impulsion chaque fois que leur contenu devient égal à zéro. Ces sorties de coïncidence C sont reliées aux entrées d'une porte OU 133 dont la sortie est reliée à l'entrée d'horloge T d'une bascule 134 de type T. La sortie Q de cette bascule 134 est reliée à l'entrée de commande de présélection PE du compteur 131 et, par l'intermédiaire d'un inverseur 135, à l' entrée de présélection PE du compteur 132. Cette sortie Qde la bascule 134 est également reliée à la sortie 13 a du circuit 13.The counters 131 and 132 each have a coincidence output C which delivers a short pulse each time their content becomes zero. These coincidence outputs C are connected to the inputs of an OR gate 133 the output of which is connected to the clock input T of a flip-flop 134 of type T. The output Q of this flip-flop 134 is connected to the input PE preselection control of the counter 131 and, via an inverter 135, to the PE preselection input of the counter 132. This output Q of the flip-flop 134 is also connected to the output 13 a of the circuit 13.

Le fonctionnement du circuit de la figure 6 va être maintenant décrit à l'aide de la figure 6 a.The operation of the circuit of FIG. 6 will now be described with the aid of FIG. 6 a.

Lorsque la sortie Qde la bascule 134 est à l'état »0«, l'entrée PE du circuit 132 est à l'état »1 «. Le contenu de ce compteur 132 prend donc un état correspondant au contenu de la mémoire 142, et ce compteur 132 reste bloqué dans cet état, qui est désigné par N 142 à la figure 6 a.When the output Q of the flip-flop 134 is in the state "0", the input PE of the circuit 132 is in the state "1". The content of this counter 132 therefore takes a state corresponding to the content of the memory 142, and this counter 132 remains blocked in this state, which is designated by N 142 in FIG. 6 a.

L'entrée PE du compteur 131 est par contre à l'état »0«, et ce compteur 131 décompte les impulsions du signal H. Lorsque son contenu atteint la valeur zéro, sa sortie C délivre une impulsion que est transmise par la porte 133 à l'entrée T de la bascule 134. La sortie Q de cette dernière, et l'entrée PE du compteur 131 passent donc à l'état 1 «. Le contenu de ce compteur 131 prend donc un état correspondant au contenu de la mémoire 141, et ce compteur 131 se bloque dans cet état, qui est désigné par N 141 à la figure 6 a. Simultanément, l'entrée PE du compteur 132 passe à l'état »0«. Ce compteur 132 commence à décompter les impulsions du signal H. Lorsque son contenu atteint la valeur zéro, sa sortie C délivre une impulsion qui est transmise par la porte 133 à l'entrée T de la bascule 134. La sortie Q de cette dernière repasse à l'état »0«, et le processus décrit ci-dessus recommence.The input PE of the counter 131 on the other hand is in the state "0", and this counter 131 counts the pulses of the signal H. When its content reaches the value zero, its output C delivers a pulse which is transmitted by the gate 133 at the input T of the flip-flop 134. The output Q of the latter, and the input PE of the counter 131 therefore change to state 1 ". The content of this counter 131 therefore takes a state corresponding to the content of the memory 141, and this counter 131 hangs in this state, which is designated by N 141 in FIG. 6 a. At the same time, the PE input of counter 132 changes to state »0«. This counter 132 begins to count the pulses of the signal H. When its content reaches the value zero, its output C delivers a pulse which is transmitted by the gate 133 to the input T of the flip-flop 134. The output Q of the latter switches back in state "0", and the process described above begins again.

La sortie Q de la bascule 134, qui délivre le signal M, passe donc alternativement à l'état »0« et à l'état »1 « pendant des durées qui dépendent de la fréquence du signal H et du contenu des mémoires 141, respectivement 142.The output Q of the flip-flop 134, which delivers the signal M, therefore switches alternately to the state "0" and to the state "1" for durations which depend on the frequency of the signal H and on the content of the memories 141, respectively 142.

La durée des périodes d'interruption des impulsions motrices, qui est égale à la durée pendant laquelle le signal M est à l'état »1 «, et la durée des impulsions élémentaires qui séparent ces périodes d'interruption, qui est égale à la durée pendant laquelle le signal M est à l'etat »0«, peuvent donc être déterminées indépendamment l'une de l'autre. La manière dont ces durées sont déterminées est quelconque. Elles peuvent être fixes ou varier, d'une manière qui ne sera pas décrite ici, en fonction de paramètres tels que la tension de la source d'alimentation 10, ou la charge mécanique entraînée par le moteur, ou tout autre paramètre.The duration of the periods of interruption of the driving pulses, which is equal to the duration during which the signal M is in the state "1", and the duration of the elementary pulses which separate these periods of interruption, which is equal to the duration during which the signal M is in the state "0", can therefore be determined independently of one another. The manner in which these durations are determined is arbitrary. They can be fixed or vary, in a way that will not be described here, in function of parameters such as the voltage of the power source 10, or the mechanical load driven by the motor, or any other parameter.

Claims (12)

1. Process for reducing the consumption of a stepping motor which includes a winding (1, 2) having a resistance (2) of magnitude R and inductance (1) of magnitude L and a rotor (1 a) magnetically coupled to said winding (1,2) consisting of switching on, each time the rotor (1 a) is to rotate through a step, a series of basic motor pulses separated by interruption periods of duration T 1 during which the winding (1, 2) is essentially short-circuited, of detecting the mechanical load driven by the rotor (1 a) during its rotation by measuring a magnitude representative of the variation of voltage (Ui) induced in the winding by the rotation of the rotor (1 a) and, of slaving the duration of said series of pulses to said mechanical load, characterized by the fact that it consists of measuring said magnitude representative of said variation of the induced voltage (U,) during each of said interruption periods.
2. Process according to claim 1 characterized by the fact that is consists of measuring said magnitude representative of the variation of the induced voltage (Ui) by measuring the gauge voltage (u) produced in a gauge resistance (17) of magnitude Rm by the current circulating in the winding (1, 2), of memorising the value (Ua) of this gauge voltage (u) at the beginning of the interruption period, of forming the product of the memorised value (Ua) by a first constant factor equal to
Figure imgb0059
 where τ =
Figure imgb0060
 , of forming the difference between said product and the gauge (u) and, of comparing said difference with a second constant factor equal to
Figure imgb0061
where Uis is a predetermined reference voltage, the time (Td) which elapses between the beginning (to) of said series of pulses and the instant (ti) when said difference becomes equal to or greaterthan said second factor being representative of said variation of the induced voltage (Ui).
3. Process according to claim 1 characterized by the fact that it consists of measuring said magnitude representative of the variation of the induced voltage (U;) by measuring the gauge voltage (u) produced in a gauge resistance (17) of magnitude Rm by the current (i) circulating in the winding (1, 2), of memorising the value (U.) of this gauge voltage (u) at the beginning of the interruption period, of forming the product of the measured value (Ua) by a first factor equal to
Figure imgb0062
 where τ =
Figure imgb0063
 , of forming the difference between said product and a second constant factor equal to
Figure imgb0064
where U,, is a predetermined reference voltage and, of comparing said difference with the gauge voltage (u), the time (Td) which elapses between the beginning (to) of said series of pulses and the instant (t1) when said gauge voltage (u) becomes equal to or less than said difference being representative of said variation of the induced voltage (Ui).
4. Process according to claim 1 characterized by the fact that it consists of measuring said magnitude representative of the variation of the induced voltage (Ui) by measuring a first (Ua) and a second (Ub) voltage produced in a gauge resistance (17) of magnitude Rm bythe current (i) circulating in the winding at respective first and second instants separated by a time interval of duration T 1' less than or equal to T 1, of forming the product of the first voltage (Ua) by a first fac- tor equal to T where r= of forming the difference between said product and said second voltage (Ub) and of comparing said difference with a second constant factor equal to
Figure imgb0065
where Uis is a predetermined reference voltage, the time (Td) which elapses between the beginning (to) of said series of pulses and the instant (t1) when said difference becomes equal or greater to said second factor being representative of said variation of the induced voltage (Ui).
5. Process according to claim 1 characterized by the fact that it consists of measuring said magnitude representative of the variation of the induced voltage (Ui) by measuring a first (Ua) and a second (Ub) voltage produced in a gauge resistance (17) of magnitude Rm by the current (i) circulating in the winding (1, 2) at respective first and second instants separated by a time interval of duration T 1' less than or equal to T 1, of forming the product of the first voltage (Ua) and of a first constant factor equal to
Figure imgb0066
 where
Figure imgb0067
 of forming the difference between said product and a second constant factor equal to
Figure imgb0068
where Uis is a predetermined reference voltage and, of comparing said difference with said second voltage (Ub), the time which elapses between the beginning (to) of said series of pulses and the instant (t1) when said second voltage (Ub) becomes equal to or less than said difference being representative of said variation of the induced voltage (Ui).
6. Process according to claim 4 or 5 characterized by the fact that said first and second instant coincide respectively with the beginning and the end of each interruption period.
7. Arrangement for controlling a stepping motor which includes a winding (1, 2) having a resistance (2) of magnitude R and inductance (1) of magnitude L and a rotor (1 a) magnetically coupled to said winding (1,2), the arrangement including means (8, 9) for producing a control signal (J) each time the rotor (1 a) is to rotate through a step, means (13, 14) for producing a chopping signal (M), means (12, 15) responsive to the control signal (J) and the chopping signal (M) for applying to the winding (1, 2) a series of basic motor pulses separated by interruption periods of duration T1 during which the winding (1, 2) is esentially short-circuited, means for detecting the mechanical load driven by the rotor (1 a) during its rotation comprising means (16) for measuring a magnitude representative of the variation of the voltage Ui induced in the winding (1,2) by the rotation of the rotor (1 a), and means (26) or slaving the duration of said series of pulses to said mechanical load, characterized by the fact that said means (16) for measuring said magnitude representative of said induced voltage (Ui) comprise means (17, 18, 20-25; 23', 25') responding to said chopping signal (M) for measuring said magnitude representative of said induced voltage (Ui) during each of said interruption periods.
8. Arrangement according to claim 7 characterized by the fact that the means (17, 18, 20-25; 23', 25') for measuring the magnitude representative of the variation of the induced voltage (Ui) include means comprising a gauge resistance (17) of magnitude Rm for producing a gauge voltage (u) representative of the current (i) circulating in the winding (1, 2), means (18, 20, 22) for memorising the value of the gauge voltage (u) at the beginning of each interruption period, means (231, 232) for forming the product of the memorised value by a first constant factor equal to
Figure imgb0069
, where τ=
Figure imgb0070
, means (233', 234', 235') for forming the difference between said product and the gauge voltage (u), and means (24,25') for comparing said difference with a second constant factor equal to
Figure imgb0071
where Uis is a predetermined reference voltage, the time (Td) which elapses between the beginning (to) of said series of pulses and the instant (t1) when said difference becomes equal to or greater than said second factor being representative of said variation of the induced voltage (Ui).
9. Arrangement according to claim 7 characterized by the fact that the means (17, 18, 20-25; 23', 25') for measuring the magnitude representative of the variation of the induced voltage (U;) include means comprising a gauge resistance (17) of magnitude Rm for producing a gauge voltage (u) representative of the current (i) circulating in the winding (1, 2), means (18, 20, 22) for memorising the value of the gauge voltage at the beginning of each interruption period, means (231, 232) for forming the product of the memorised value by a first constant factor equal to
Figure imgb0072
 , where τ=
Figure imgb0073
 , means (23) for forming the difference between said product and a second constant factor equal to
Figure imgb0074
where Uis is a predetermined reference voltage, and means (25) for comparing said difference with the gauge voltage (u), the time (Td) which elapses between the beginning (to) of said series of pulses and the instant (t1) when said gauge voltage (u) becomes equal to or less than said difference being representative of said variation of the induced voltage (Ui).
10. Arrangement according to claim 7 characterized by the fact that the means (17, 18, 20-25; 23', 25') for measuring the magnitude representative of the variation of the induced voltage (U;) include means comprising a gauge resistance (17) of magnitude Rm for measuring a first (Ua) and a second (Ub) voltage produced by the current circulating in the winding (1, 2) at respective first and second instants separated by a time interval of duration T 1' less than or equal to T 1, means (231, 232) for forming the product of the first voltage (Ua) by a first factor equal to τ - T1' τ , where τ = L R , means (233', 234', 235') for forming the difference between said product and said second voltage (Ub), and means (24, 25') for comparing said difference with a second constant factor equal to
Figure imgb0075
where Uis is a predetermined reference voltage, the time (Td) which elapses between the beginning (to) of said series of pulses and the instant (ti) when said difference becomes equal to or superior than said second factor being representative of said variation of the induced voltage (Ui).
11. Arrangement according to claim 7 characterized by the fact that the means (17, 18, 20-25; 23', 25') for measuring the magnitude representative of the variation of the induced voltage (Ui) include means comprising a gauge resistance (17) of magnitude Rm for measuring a first (Ua) and a second (Ub) voltage produced by the current (i) circulating in the winding (1, 2) at respective first and second instants separated by a time interval of duration T 1' less than or equal to T 1, means (231, 232) for forming the product of the first voltage (Ua) by a first factor equal to
Figure imgb0076
, where τ = L R , means (232) for forming the difference between said product and a second constant factor equal to
Figure imgb0077
where Uis is a predetermined reference voltage, and means (25) for comparing said difference with said second voltage (Ub), the time (Td) which elapses between the beginning (to) of said series of pulses and the instant (t1) when said second voltage (Ub) becomes equal to or less than said difference being representative of said variation of the induced voltage (Ui). 12. Arrangement according to claim 11 or 12 characterized by the fact that said first and second instants coincide respectively with the beginning and the end of each interruption period.
EP82810396A 1981-10-02 1982-09-23 Process for reducing the consumption of a stepping motor, and device to carry out this process Expired EP0076780B1 (en)

Applications Claiming Priority (2)

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CH6340/81 1981-10-02
CH634081A CH646575GA3 (en) 1981-10-02 1981-10-02

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EP (1) EP0076780B1 (en)
JP (1) JPS5869500A (en)
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JPH0332396A (en) * 1989-06-28 1991-02-12 Sharp Corp Stepping motor driver
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JPS5869500A (en) 1983-04-25
EP0076780A1 (en) 1983-04-13
CH646575GA3 (en) 1984-12-14
US4468602A (en) 1984-08-28
DE3268162D1 (en) 1986-02-06
JPH0564038B2 (en) 1993-09-13

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