FR2899347A1 - Solenoid valve controlling device for flight controlling system of aircraft, has current regulation circuit to regulate supply of holding current to solenoid valve, when holding current reaches magnetizing current - Google Patents

Abstract

The device (1) has a current regulation circuit (4) including a field programmable gate array circuit (3) that is provided in a solenoid valve (2). The regulation circuit permits to regulate the supply of a holding current (Imt), to the solenoid valve, that is lesser than a magnetizing current (Im), when the holding current passing in the solenoid valve reaches the magnetizing current and crosses the magnetizing current during a magnetizing time. An independent claim is also included for a method for controlling a solenoid valve.

Description

The present invention relates to a control device of a

  solenoid valve to minimize power consumption.

  TECHNICAL FIELD A solenoid valve in the present invention is an electrically controlled device allowing to allow or interrupt the passage of a fluid in a system such as a hydraulic circuit. The solenoid valve is an inductance surrounding a magnetic core. To control the solenoid valve, a current is circulated in the inductance thus allowing the displacement of the magnetic core.

  The operation of the solenoid valve is in two stages. The first step is to supply the inductor with a sufficiently high current to overcome the frictional forces of the associated hydraulic actuator and put it in the desired position (a step commonly called bonding of the solenoid valve). The second step is then to maintain this position. The switching (magnetization) requires a high call power is a high current, which is no longer the case when the solenoid valve is closed (in the holding phase). Holding the solenoid valve in the closed position requires a lower current than that required for switching. The graph of FIG. 1 shows the minimum current required to switch and maintain the actuator associated with the inductor as a function of time. As illustrated in the graph, to allow the closure of the solenoid valve, the necessary current is the magnetization current lm. The magnetization current must be maintained for a certain time, called the magnetization time Tm. When the solenoid valve is closed, the current required to maintain it in this state may be lower, at least equal to the holding current Imt.30 PRIOR TECHNIQUE

  The solenoid valves are used in multiple applications and for example, to control the movements of a rudder of an aircraft. Computers on board the aircraft control the movements of said rudder including controlling a hydraulic flow with a solenoid valve.

  The solutions used on the computers control the solenoid valves in all or nothing: a voltage is applied across the inductance. The value of the circulating current is then constant and simply a function of its own impedance (in steady state the impedance of the inductance corresponds to its resistive value) as well as the applied voltage. There is not, by this principle, a distinction between magnetization and maintenance. The power consumption is, therefore, during the maintenance phase greatly increased compared to the real need; the analysis shows that overconsumption can go up to 50%.

  An object of the present invention is to provide a solenoid valve control device for minimizing current consumption.

SUMMARY OF THE INVENTION

  To do this, the present invention provides a solenoid valve control device for finer management of the current consumed by it.

  The present invention relates to a device for controlling a solenoid valve, characterized in that it comprises a circuit for controlling a current supply circuit of said solenoid valve enabling detection of a predetermined regulation current value reached. in the solenoid valve to modify after a given time delay the regulation of the current flowing in said solenoid valve to a lower current value.

  In this way, the control circuit makes it possible to spend less current.

  The control device comprises: - said supply circuit of a current IEV in the solenoid valve; a detection circuit of a predetermined regulation value Imax reached by the current 'EV in the solenoid valve delivering on detection of this current Imax a signal S3 to said control circuit; a circuit for modifying the predetermined value Imax detected by the circuit; said control circuit: of said current supply circuit so as to regulate the current at the level Imax detected by said detection circuit; A delay on detection of said predetermined value; • said modification circuit so as to change once the timer elapsed the regulation level on detection of said predetermined value.

  The control device is designed in a manner adapted to the solenoid valve that it controls: the maximum value detected corresponds to the magnetization current of the solenoid valve and the modification circuit modifies, on receipt of a signal S1 of the circuit, the value of the solenoid valve. regulated current of the magnetization current at holding current.

  According to a particular embodiment of said supply circuit, the supply circuit comprises a chopper circuit controlled by the control circuit through a transistor of said chopper circuit.

  According to a particular embodiment of the device according to the present invention, the device comprises a chopper circuit controlled by the programmable circuit for regulating the current in the solenoid valve, the programmable circuit 4 determining the control value by modifying the duty cycle of the transmitted signal. to the chopper circuit.

  The programmable circuit determines the duty cycle by means of a signal transmitted by a hysteresis circuit making it possible to detect a desired regulation reached value in the solenoid valve.

  According to a particular embodiment of said detection circuit, the detection circuit comprises a hysteresis circuit whose input voltage corresponds to the voltage across a resistor of said chopper circuit through which passes the maximum current Imax flowing in said solenoid valve and whose highest switching threshold is equal to the maximum input voltage, corresponding to said maximum current, said circuit generating and transmitting a determined signal to said circuit when the current Imax is reached. According to a particular embodiment of said modification circuit, the modification circuit comprises a circuit comprising a transistor controlled by the control circuit so that when the transistor is open, the circuit corresponds to said hysteresis circuit and when the transistor is closed, resistors are connected in parallel with one or more resistors of the hysteresis circuit so as to modify the value of the switching threshold.

  According to a particular embodiment of said control circuit, the control circuit comprises a FPGA-type programmable circuit. The present invention also relates to the method for controlling said solenoid valve, characterized in that it consists in controlling the current supply circuit of said solenoid valve so as to modify on detection of a predetermined regulation current value reached in 30 minutes. the solenoid valve after a determined delay the regulation of the current flowing in said solenoid valve to a lower current value. According to a particular application, the present invention relates to a flight control system equipped with a control device according to the present invention.

  According to a particular application, the present invention relates to an aircraft equipped with a control device according to the present invention. SUMMARY DESCRIPTION OF THE DRAWINGS

  Other objects, advantages and features of the invention will appear on reading the following description of the device according to the invention, given by way of non-limiting example with reference to the accompanying drawings, in which: FIG. 1 is a diagram showing the shape of the optimum current required to supply a solenoid valve in order to put an associated actuator in a desired position and to maintain it in this position as a function of time; FIG. 2 schematically shows functional blocks of a solenoid control device according to the present invention; FIG. 3 is a block diagram showing the various steps of a method of controlling a solenoid valve according to the present invention; FIG. 4 is a schematic electronic representation of an embodiment of the supply circuit of the solenoid valve shown in FIG. 2; • Figure 5 maps diagrams of different values representative of the power circuit shown in Figure 4; • Figure 6 maps diagrams of different

  6 values representative of the supply circuit and the control device of the solenoid valve according to the present invention; FIG. 7 is a schematic electronic representation of an embodiment of a portion of the detection circuit shown in FIG. 2; FIG. 8 is a diagram showing the operation of the embodiment of the circuit shown in FIG. 7, namely the output voltage values as a function of the input voltage values of said circuit; FIG. 9 is a schematic electronic representation of a module making it possible to modify the value detected by the circuit shown in FIG. 7 to which it is connected; FIG. 10 is a schematic electronic representation of a particular embodiment of a shaping circuit of the device according to the present invention; Fig. 11 is a diagram showing the operation of the embodiment of the shaping circuit shown in Fig. 10, namely the output voltage values as a function of the input voltage values of said shaping circuit; FIG. 12 is a schematic electronic representation of a particular embodiment of an amplification and filtering circuit of the device according to the present invention.

  HOW TO CARRY OUT THE INVENTION As illustrated in FIG. 2, the device 1 for controlling a solenoid valve 2 comprises a circuit 3 for controlling a circuit 4 for regulating the current in the solenoid valve 2. The device 1 makes it possible to manage The device 1 feeds the solenoid valve 2 with a holding current Imt lower than the magnetization current lm when the current 7 passing through. in the solenoid valve reached the magnetization current and passed through it during the magnetization time Tm.

  The regulation circuit 4 comprises a current supply circuit 5 of the solenoid valve 2 and a circuit 6 for detecting a maximum current and for modifying the value of said maximum current to be detected.

  FIG. 3 shows the operation of the device 1. The control circuit 3 transmits a signal S2 to the control circuit 4 as soon as it is turned ON (step (A)): the circuit 3 uses the clock signal as signal S2. Circuit 3 uses the clock signal as signal S2. Upon receipt of the signal S2, the circuit 4 generates a current in the solenoid valve which increases until reaching a maximum value detected (steps (A) and (B)). When the detection circuit 6 detects that the current flowing in the solenoid valve has reached a maximum current, and more particularly, the magnetization current 1m (step (B)), it sends a signal S3 to the control circuit 3 for the first time. informing that the current in the solenoid valve has reached said maximum value (step (C)). As long as the magnetization time has not elapsed (step (D)), the control circuit performs magnetization current regulation of the solenoid valve (step (C)). When the time delay has elapsed and more particularly when it has reached the value of the magnetization time (Step (D)), the control circuit transmits to the detection circuit a signal SI making it possible to switch from a magnetization state. to a holding state by changing the value of the maximum current detected for the regulation (steps (E)): the maximum current changes from the magnetization current value to the holding current value (step (F)). The regulation circuit 4 then performs the regulation of the solenoid valve in the holding current (steps (G) and (H)). Stopping the control circuit 3 (setting OFF) implies a decrease in the current until the cancellation of the latter (steps (I) and (J)).

  The following description details one embodiment of the device 1 according to the present invention.

  The control circuit 3 is a programmable circuit, for example of the FPGA (Field Programmable Gate Array) type. The circuit 3 comprises a non-volatile memory program for transmitting current regulation signals S 2 and current S 1 to the control circuit 4 of the solenoid valve in the state of magnetization to the state of maintenance at the desired moments. ; the timer whose value is equal to the magnetization time is configurable.

  As illustrated in FIG. 4, the current supply circuit 5 is based on the known principle of a chopper circuit. The circuit 5 comprises a switch, in the embodiment illustrated in FIG. 4, in the form of a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) field-effect transistor 8 controlled at the level of FIG. the gate by the signal S2 from the control circuit 3. The voltage S2 applied to the gate of transistor 8 makes it possible to control a current Is at the outlet of the drain. The current Is leaving the drain passes through a resistor 9 called detection resistor Rs ensuring the measurement of the current flowing in the solenoid valve (only when the transistor 8 is closed). A diode 10 called freewheeling diode is placed between the solenoid valve 2 and the transistor 8 to allow the current restored by the solenoid valve to flow when the transistor 8 is open. The solenoid valve is characterized by an inductance 11 L and a resistor 12 R. The circuit 5 is powered by a voltage Vsupply.

  Figure 5 shows the different representative currents and voltages in the chopper circuit as a function of time: EV the current flowing through the solenoid valve; ID the current flowing through the diode 10; ls the current passing through the resistor 9; S2 the control voltage of transistor 8. The voltage S2 is a series of periodic pulses. When the voltage S2 is high, the transistor is closed and the current Is in the resistor 9 and in the solenoid valve increases. At the falling edge of the impulse, when the voltage on the gate of the transistor 8 takes the value zero, the transistor opens: the current flowing through the resistor 9 is then zero and the current flowing through the solenoid valve and the diode in closed circuit decreases. The IEV current flowing through the solenoid valve is therefore equal to the current flowing through the resistor 9 when the transistor is closed and to the current flowing through the diode when the transistor is open. As shown in the figures representing the current Is and IEV, the detection of the maximum current reached by the current 'EV flowing in the solenoid valve can be achieved by the detection of the maximum current reached by the current lS through the resistor 9. The circuit 6 detection as will be seen later is based on the measurement of the current through the resistor 9 for the detection of the maximum current and more precisely the voltage across the resistor 9. The voltage across the resistor 9 is the ratio of said resistance near the image of the current flowing in the solenoid valve (when the transistor is closed). The control of the current flowing in the solenoid valve is effected by limiting the value of the maximum current flowing in the transistor 8: to control the value of the current flowing in the solenoid valve, it suffices to open the transistor 8 when the value current is equal to the value of the desired current. The duty cycle D of the signal S2 (which is also that of the three currents IEV, ID, IS) is a function of the value of the desired maximum current Imax, of the voltage drop in the diode VD, of the supply voltage Vsupply, the resistance R of the solenoid valve 12. The duty cycle is calculated as follows: RI max + VD D = Vsupply + VD

  The voltage drop in the diode VD corresponds to the voltage across the diode when the diode is in the on state; the voltage drop is specified for a diode according to the current flowing through it, here the current Imax.

  Therefore, if the supply voltage is stable, the variation of the duty cycle makes it possible to modify the value of the maximum current. Thus, the control circuit 3 associated with the circuit 6 sets the value of the maximum current by acting on the duty cycle of the signal S2 transmitted to the circuit 5. The circuit 3 at its start-up sends a signal S2 to the gate of the transistor 8 of which the duty cycle is determined to set a current value in the desired maximum solenoid valve equal to the magnetization current to switch the solenoid valve or the holding current after switching.

  The FPGA type programmable circuit 3 has an internal clock signal whose frequency can be adjusted. The frequency should be as high as possible in order to minimize the current ripple. The circuit 3, when put into operation, sends on the gate of transistor 8 said clock signal (through a driver). The clock signal is shown in Figure 6 (signal H). The duty cycle of the clock signal is initially fixed at a very high value (the higher the value of the ratio, the higher the maximum current setpoint (magnetization current) will be reached quickly: the ratio can be fixed for example at 98% or even 100% (constant signal)) so as to increase the current flowing in the solenoid valve. The higher the ratio, the faster the load and the faster the maximum current setpoint. The rising edge of the clock signal implies the transition to the high state of the signal S2: indeed, as previously seen, when the device 1 is put into operation, the signal S2 corresponds to the clock signal.

  Once the desired reference current value Imax (i.e. magnetization current lm) is reached, transistor 8 must be open. Following this opening, the current flowing in the transistor 8 is zero and passes entirely into the diode: the current in the solenoid valve decreases.

  The detection of the current Imax is carried out through the detection circuit 6 shown in FIG. 7. The circuit 7 generates a pulse when the value of the current Imax is reached. The pulse is transmitted to the control circuit 3. When the control circuit 3 receives the signal S3 and more particularly the said pulse, the circuit 3 sets the signal S2 to zero on the rising edge of the said pulse. Transistor 8 receiving zero voltage on its gate closes. The transistor opens again only on appearance of a new rising edge of the clock signal and therefore the signal S2. The absence of this rising edge would imply a decrease of the current until the cancellation of the solenoid valve current. The duration of the pulse S3 can be adjusted according to the needs of the user.

  The circuit 3 is thus programmed to deliver to the control circuit 4 a signal S2 generated as described above. The program of the circuit 3 produces a signal S2 in the following manner: a rising edge of the signal S2 on the rising edge of the clock, a falling edge on the rising edge of a pulse received from the circuit 6. The circuit 3 transmits the signal S2 thus elaborated at the circuit 4.

  As seen above, the detection of the maximum current flowing in the solenoid valve is through the measurement of the current flowing in the resistor 9 or through the measurement of the voltage across the resistor 9 since according to the law of Ohm, the voltage across the resistor 9 is equal to the product of its resistance Rs by the intensity of the current Is passing through it (Us = Rs * ls). The detection circuit 6 compares the value of the voltage across the resistor 9 with a reference voltage Uref corresponding to the predetermined maximum current value (Uref = Rs * lm), namely the value of the magnetization current. The circuit 6 sends an information (signal pulse S3 in FIG. 6) to the control circuit 3 to inform it that the current flowing in the solenoid valve has reached the predefined maximum value. In this way, the control circuit 3 modulates the duty cycle of the signal S2 of

  12 to regulate the current in the solenoid valve to the maximum detected current as described above.

  According to an illustrative embodiment of the detection circuit 6 shown in FIG. 7, the circuit 6 is a hysteresis circuit. FIG. 8 represents the voltage Vout delivered by the hysteresis comparator as a function of the input voltage Vs. The circuit 6 delivers a voltage at the output Vout which depends on the voltage present at the input Vs, and therefore as seen previously of the current flowing in the solenoid valve. The output voltage Vout takes two different values according to the input voltage Vs: when the input voltage Vs is lower than VHy High, the output voltage of the circuit Vout is equal to VPuIIUp (at the voltage drop close in the resistor Rpuäup, this voltage can be neglected) and when the input voltage Vs is greater than Vref, the output voltage of the circuit goes to zero. The value of the thresholds is defined in such a way that the switching threshold (zero volt transition of the output voltage Vout) is equal to the reference voltage (Vref = lmax * Rs). The threshold VHyHigh must be low enough so that there is not an unwanted re-engagement of the transistor 8 (current ripple greater than the current delta corresponding to the delta hysteresis).

  The reference voltage Vref is given by the following equation: ## EQU1 ## R, The different resistors R5, R6 and R7 being represented in the diagram of the hysteresis circuit of FIG. 7 are therefore chosen so that the threshold Vref corresponds to the maximum voltage Vs and therefore to the maximum current to be detected (magnetization current lm). The voltage Valim of the hysteresis circuit in FIG. 7 can be the conventional supply voltage of a hysteresis comparator or take any other value. On the other hand, the voltage Vpullup must be compatible with the input voltages of the circuit making it possible to shape the signal S3.

  The detection circuit 6 also makes it possible, after the delay (corresponding to the magnetization time), to modify the reference value Vref of the hysteresis circuit in order to lower the level of the current flowing in the solenoid valve so as to obtain a holding current regulation and thus to pass in the maintenance state. For this purpose, the detection circuit 6 comprises an additional module 13 shown in FIG. 9 that can be controlled by the circuit 3. The module 13 makes it possible to modify the value of the resistor R6 of the hysteresis circuit (on which the voltage Vref depends. ) by putting the resistors R8 and R9 in parallel. The resistor R6 of the hysteresis circuit of FIG. 7 thus becomes the resistors R8 and R9 in parallel (R8 // R9). The signal S1 is transmitted by the control circuit 3 to close or open a MOS FET transistor 14 respectively to put said resistors in parallel or not. When the transistor 14 is open, the circuit 6 corresponds to the hysteresis circuit shown in FIG. 7. When the transistor 14 is closed, the circuit 6 corresponds to the hysteresis circuit with the resistors R8 and R9 in parallel. The value Vref of the hysteresis circuit then has the value: Va lim (R8 // R9) .R, Vpullup.R5. (R8 // R9 ù + R5. (R8 // R9) + R5 .R, + (R8 // R9) .R, R5. (R8 // R9) + R5 .R, + (R8 // R9) .R, The resistors R8 and R9 are chosen to obtain a value Vref equal to the voltage Vs corresponding to the current The overall resistance of the resistors R5, R7, R8 and R9 is chosen to obtain the threshold values Vref corresponding respectively to the magnetization current and the holding current. FIG. 9 controls the transistor 14 through a gate resistor Rg and a foot resistor Rp. The resistor Vref

  Gate 14 sets the opening and closing times and the foot resistor provides potential on the gate when there is none.

  It is the control circuit 3 which triggers the transition from the magnetization state to the holding state. When the control circuit 3 receives from the detection circuit 6 the signal S3 indicating that the magnetization current has been reached, the circuit 3 has a counter or any other hardware and / or software component enabling a delay to be triggered after which the circuit 3 transmits the signal S1 to the circuit 6 and more specifically to the module 13 of the circuit 6. The circuit 3 is programmed so as to develop a signal S1 after timing to control the transistor of the circuit 6 to modify the switching threshold of the hysteresis circuit. The circuit 6 transmits a signal S3 when it detects that the value of the current in the solenoid valve has reached the new threshold corresponding to the holding current. The circuit 3 on receipt of the signal S3 develops a new signal S1 whose new duty cycle is such that the circuit 3 controls the regulation in the solenoid valve at the holding current.

  According to a particular embodiment of the present invention, the signal obtained by the hysteresis circuit 6 is shaped before being transmitted to the control circuit 3. Indeed, as previously seen, when the magnetization current is reached, the detection circuit informs the control circuit 3 by a zero output voltage. However, as shown in FIG. 6, the signal S3 transmits a pulse and informs in the illustrated embodiment the control circuit 3 on the rising edge. The shaping circuit therefore makes it possible to transmit a rising edge to the control circuit 3 when the magnetization current is reached.

  The shaping circuit uses a trigger circuit shown in Fig. 10. Fig. 11 shows the voltage values at the output of the trigger as a function of the input voltage values. When the input voltage (which corresponds to the output voltage of the hysteresis circuit) has the value 0, the output voltage is

  15 equal to VAdapt: the signal S3 corresponding to the output voltage of the trigger circuit therefore transmits a rising edge when the current of the solenoid valve reaches the maximum current, namely the magnetization current.

  According to a particular embodiment of the invention, the device 1 comprises a circuit 15 for amplifying the voltage present across the resistor 9. Indeed, the resistance 9 must be minimized to the maximum so as not to increase the resistance total of line (increase of losses) and / or the maximum current to be detected can be weak. In addition, a filter is performed on the voltage value across

  the resistor 9 to suppress parasitic line oscillations due to line parasitic inductance. The amplification and the filtering are carried out using the circuit 15 shown in FIG. 12. The circuit 15 is an operational amplifier-based diagram associated with RC filters making it possible to offer a filtering function while amplifying the signal.

  The amplification ratio of the assembly and the cut-off frequency of the filter (R1 // R3 // C1) are cloned by the following formulas: Gain R3 i R G = -. 1 + G = Ra R, + R3 R2 is R2 if R3 = R4 and R1 = R2 Cutoff frequency 1 2.n R3.R, \. R3 + R, The values of the amplification ratio and the cutoff frequency are set according to the needs taking into account the charging time of the RC network. Indeed, if the charging time of said RC network is not much lower fc = .C,

  16 at the time during which the current flows in the switch 8, an error on the voltage level across the detection resistor is introduced, thus distorting the detection.

  In the case of an amplification, the tilt threshold of the hysteresis circuit must take into account the value of the amplification. If the gain is G, the switchover threshold is Vref = Rs * lm * G.

Claims (9)

  1-control device of a solenoid valve (2) characterized in that it comprises a circuit (3) for controlling a circuit (5) for supplying power to said solenoid valve (2) allowing detection (6) a predetermined regulation current value reached in the solenoid valve to change after a given delay the regulation of the current flowing in said solenoid valve to a lower current value.   2- Control device according to claim 1, characterized in that it comprises: - said circuit (5) for supplying a current 'EV in the solenoid valve; a circuit (6) for detecting a predetermined regulation value Imax reached by the current 'EV in the solenoid valve delivering, on detection of this current Imax, a signal S3 to said control circuit (3); a circuit (6) for modifying the predetermined value Imax detected by the circuit (6); said control circuit: of said current supply circuit (5) so as to regulate the current at the level Imax detected by said detection circuit; A delay on detection of said predetermined value; • said modification circuit (6) so as to change once the elapsed time the regulation level on detection of said predetermined value.   3-Control device according to one of claims 1 or 2, characterized in that the maximum value detected corresponds to the magnetization current of the solenoid valve and the modification circuit modifies upon receipt of a signal S1 of the circuit 3 la value of the regulated current of the holding current magnetizing current.   4-Detection device according to one of claims 1 to 3, characterized in that the supply circuit (5) comprises a chopper circuit (5) controlled by the control circuit (3) through a transistor (8) of said chopper circuit.   5-Device according to claim 4, characterized in that the detection circuit (6) comprises a hysteresis circuit whose input voltage corresponds to the voltage across a resistor of said chopper circuit through which passes the maximum current Imax circulating in said solenoid valve and whose highest switching threshold is equal to the maximum input voltage corresponding to said maximum current, said circuit generating and transmitting a determined signal to said circuit (3) when the current Imax is reached.   6-Device according to claim 5, characterized in that the circuit (6) for modifying comprises a circuit comprising a transistor (8) controlled by the control circuit (3) so that when the transistor is open, the circuit corresponds to said hysteresis circuit and when the transistor is closed, resistors are put in parallel with one or more resistors of the hysteresis circuit so as to modify the value of the switching threshold. 7. Device according to one of the preceding claims, characterized in that the control circuit (3) comprises a programmable circuit of the FPGA type. 8 - A method for controlling a solenoid valve (2), characterized in that it consists in controlling a current supply circuit (5) for said solenoid valve (2) so as to modify on detection (6) a predetermined control current value reached in the solenoid valve after a determined delay the regulation of the current flowing in said solenoid valve to a lower current value. 9- Flight control system characterized in that it comprises a device according to one of claims 1 to 7.10- Aircone characterized in that it comprises the device according to one of claims 1 to 7.