Method for controlling a bistable electromagnetic actuator

Abstract

The invention relates to a method for controlling a bistable electromagnetic actuator comprising steps of: upon receiving a transition command between two stable positions of the actuator, applying a first voltage (Ve) to an electromagnet coil of the actuator capable of moving a core of the actuator and monitoring a current (I1, I2) flowing through the electromagnet coil; and when the current in the electromagnet coil crosses a threshold value (ILM1, -ILM2), de-energizing the electromagnet coil, the threshold value being greater in absolute value than a minimum value (ISM1, ISM2) of the current to be supplied to the electromagnet to move the core. Figure 2

Description

Title of the invention: Method for controlling a bistable electromagnetic actuator. Technical field

[0001] The present invention relates to the field of bistable electromagnetic actuators used in particular in aircraft, for example to control a hydraulic valve of an aircraft braking system. State of the art

[0002] Conventionally, an electromagnetic actuator comprises an electromagnet with a coil and a movable ferromagnetic core inside the coil. In a bistable electromagnetic actuator, the core has two stable positions, for example, a retracted position and an extended position. Unlike conventional actuators, a bistable actuator does not require power to maintain itself in one of the two stable positions, and therefore only consumes energy to change state.

[0003] Such actuators are used in hydraulic valves, particularly in aircraft braking systems. Some of these systems include a normal braking system, an emergency braking system that supplements the normal braking system in the event of a failure, and a parking brake system to keep the aircraft stationary. The emergency braking system provides brake pressure that varies according to a pilot command. The parking brake system maintains brake pressure when the aircraft is stationary and when all aircraft power supplies are shut down. The use of a hydraulic valve with a bistable electromagnetic actuator is desirable to simultaneously provide the parking brake function when all power supplies are cut off.It is also desirable to be able to use such a bistable actuator in high-frequency switched control mode to adjust the braking pressure according to a pilot command.

[0004] The control of the electromagnet of a bistable electromagnetic actuator is based on a voltage or current supply via a fixed-duration time delay or a signal from an external sensor. The external sensor is intended to signal the end of the actuator's travel or to indicate actuator movement, for example by providing a pressure measurement in the case of a hydraulic valve.

[0005] It turns out that implementing a fixed-duration time delay requires allowing relatively large margins on the duration of the time delay. Indeed, It is essential to ensure that, under all environmental conditions (ambient temperature, fluid temperature in the case of a solenoid valve, supply voltage, wear, etc.), the actuator's moving core has sufficient time to transition between its two stable positions, for example, extended and deployed. Consequently, this fixed time delay can be significant and cannot be adjusted to the necessary reduced value, leading to a power consumption issue.

[0006] Furthermore, implementing a limit switch or pressure sensor raises problems, particularly regarding integration within the actuator. Adding an external sensor (to the valve assembly) also leads to additional cost and increased mass, not only due to the sensor itself, but also to the necessary external equipment, such as a connector and electrical harness, as well as electronic power supply and electromagnetic wave filtering components. This equipment also reduces the overall reliability. While these drawbacks remain, they are less pronounced when a sensor is integrated into the valve assembly.

[0007] On the other hand, when the actuator is controlled by alternating high-frequency commands, for example by PWM (Pulse-Width Modulation), the electromagnet is subjected to a quasi-continuous power supply. However, bistable actuators are rarely thermally designed to withstand such a quasi-continuous power supply or a high activation frequency.

[0008] Furthermore, the activation force that determines the sizing of an electromagnet is based on a compromise between a high number of turns and a higher inrush current. However, the inrush current requires a low coil resistance and must therefore be regulated or limited in the case of voltage control, otherwise the current permissible by the system incorporating the actuator (for example, an aircraft circuit breaker) may be exceeded or excessively rapid heating may occur.

[0009] It is therefore desirable to provide a method for controlling a bistable type electromagnetic actuator with relatively low power consumption and whose control does not require an external sensor. Summary

[0010] Embodiments relate to a method for controlling a bistable electromagnetic actuator comprising steps of: upon receiving a transition command between two stable positions of the actuator, applying a first voltage to an electromagnet coil of the actuator capable of moving a core of the actuator and monitoring a current flowing through the electromagnet coil, and when the current in the electromagnet coil crosses a threshold value greater in absolute value than a minimum value of current to be supplied to the electromagnet to move the core, place the coil electromagnet off.

[0011] Thanks to these provisions, the actuator comprising such an electromagnet exhibits reduced power consumption and, consequently, reduced heating. The switching times of the electromagnet are also reduced. The latter can therefore be controlled at high frequencies, as in the braking systems of certain aircraft to adjust braking pressure. Furthermore, the electromagnet is controlled without any external sensors.

[0012] According to one embodiment, the threshold value in absolute value is set at less than 20%, and preferably less than 10% above the minimum value of current to be supplied to the electromagnet to move the core, or at less than 20%, and preferably less than 10% below a maximum value of static current reached in the electromagnet coil when the electromagnet coil is subjected to the first voltage.

[0013] Defining such a threshold makes it possible to limit the energy required to actuation the core in the electromagnet to the bare minimum.

[0014] According to one embodiment, the threshold value depends on a polarity of the first voltage, and in which: when the first voltage has a positive polarity, the threshold value is set at less than 10% above a first minimum value of current to be supplied to the electromagnet to move the core, or at less than 10% below a first maximum value of static current reached in the electromagnet coil when the electromagnet coil is subjected to the first voltage, and when the first voltage has a negative polarity, the threshold value is set at less than 10% below a second maximum value of current to be supplied to the electromagnet to move the core, or at less than 10% above a second minimum value of static current reached in the electromagnet coil when the electromagnet coil is subjected to the first voltage.

[0015] Defining such thresholds makes it possible to limit the energy required to actuation the core in the electromagnet to the bare minimum.

[0016] According to one embodiment, the threshold value in absolute value is fixed at the minimum current value to be supplied to the electromagnet to move the core to which is added a margin determined according to parameters of extreme external environmental conditions of the actuator.

[0017] Defining such a threshold makes it possible to limit the energy required to actuation the core in the electromagnet to the bare minimum.

[0018] According to one embodiment, the command is received in the form of a change of state of a two-state control signal, the state of the control signal determining a polarity of the first voltage to which the electromagnet coil is subjected.

[0019] Thus, the control of the electromagnet can be carried out from a simple two-state logic signal.

[0020] According to one embodiment, the command is received in the form of a polarity reversal of a supply voltage corresponding to the first voltage to which the electromagnet coil is subjected.

[0021] Thus, the control of the electromagnet can be carried out simply by reversing the polarity of the voltage previously applied to the coil of the electromagnet.

[0022] Embodiments may also relate to a bistable electromagnetic actuator comprising: an electromagnet coil, a moving core actuated by the electromagnet, and an electromagnet control circuit configured to implement the method as previously defined.

[0023] Embodiments may also relate to a solenoid valve controlled by such an actuator.

[0024] Embodiments may also relate to an aircraft braking system, including such a solenoid valve.

[0025] Embodiments may also relate to an aircraft comprising such a braking system. Brief description of the figures

[0026] The present invention will be better understood with the aid of the following description of exemplary embodiments with reference to the accompanying figures, in which identical reference signs correspond to structurally and / or functionally identical or similar elements.

[0027] [Fig. 1] Figure 1 schematically represents a control circuit for a bistable electromagnetic actuator, according to one embodiment,

[0028] [Fig.2] Figure 2 shows timing diagrams of signals present in the circuit actuator control, according to one embodiment,

[0029] [Fig.3] Figure 3 schematically represents a control circuit for the actuator control circuit, according to one embodiment,

[0030] [Fig.4] Figure 4 shows timing diagrams of signals present in the circuit actuator control, according to another embodiment,

[0031] [Fig.5] Figure 5 schematically represents a control circuit of a bistable electromagnetic actuator, according to another embodiment.

[0032] [Fig.6] Figure 6 schematically represents a control circuit for the actuator control circuit, according to another embodiment,

[0033] [Fig. 7] Figures 7A, 7B schematically represent in longitudinal section a example of a classic bistable solenoid valve, respectively in closed position and in open position. Detailed description

[0034] Figure 1 shows an EMC control circuit for a bistable electromagnetic actuator, according to one embodiment. The EMC control circuit comprises an H-bridge and a CTL control circuit for the H-bridge. The H-bridge includes four switches S1, S2, S3, and S4, with switch S1 connected to switches S2 and S3 and to a first terminal B3 of a coil CL of the actuator, and switch S4 connected to switches S2 and S3 and to a second terminal B4 of the coil CL. The H-bridge is subjected to a supply voltage Vs applied between a terminal B1 at the junction of switches S1 and S3 and a terminal B2 at the junction of switches S2 and S4. In Figure 1, Ve denotes the voltage across the coil CL, Il the current flowing through the coil, and I2 the current flowing through the H-bridge between the terminals B1 and B2 where the supply voltage Vs is applied.Each of the switches S1-S4 is an electronic switch, for example implemented by a transistor.

[0035] Thus, the control of switches S1-S4 allows the electromagnet to be activated and a PL core to be moved within the electromagnet between two stable positions, namely a deployed position and a retracted position. Bistable-type electromagnets are bipolarly controlled by voltage or current.

[0036] The CTL control circuit is configured to receive a COM control signal and a current measurement signal II or 12, and to control switches S1-S4 according to these signals. In one embodiment, the CTL control circuit is configured to open all switches S1-S4 when the current II or 12 reaches a negative threshold value -ILM2 or a positive threshold value ILM1.

[0037] The operation of the CTL control circuit is illustrated by the timing diagrams of the COM control signal, the current measurement signal II or 12, and the voltage Ve shown in Figure 2, and by Table 1 below, indicating the state (O: open, F: closed) of the switches S1-S4 as a function of time t and the state of the COM control.

[0038] [Tables] t tO - tl tl -t2 t2 -13 t3 -14 t4 -15 t5 -16 t6 -17 t7 -18 t8 -19 COM 1 0 0 0 0 1 1 1 1 IF OOOOOFFFO S2 OFFFOOOOO S3 OFFFOOOOO S4 OOOOOFFFO

[0039] At time t0, the control signal COM is in state 1, and all switches S1-S4 are open. The voltage Ve and the current II or 12 are therefore negative. At time t1, the control circuit CTL closes switches S2 and S3 to activate the electromagnet and thus move the core PL, for example, into the deployed position, with switches SI and S4 remaining open. From time t1, the voltage Ve changes to the voltage -Vs and the current II or 12 decreases (increases in absolute value) to a value -ISM2, producing a magnetic force in the coil CL of the electromagnet high enough to move the core PL within the coil CL at time t2. This movement implies a back electromotive force that causes the current to increase (decrease in absolute value) between time t2 and time t3.Then, the current II or 12 decreases again (increases in absolute value) between time t3 and time t4 until the negative threshold value -ILM2 (ISM2 and ILM2 represent positive values).

[0040] At time t4, all switches S1-S4 are open when the measured current I1 or I2 reaches the threshold value -ILM2. The voltage Ve then drops to 0 and the current I1 or I2 falls (in absolute value) towards 0. At time t5, the control circuit CTL closes switches S1 and S4 to activate the electromagnet T and move the core PL, for example, into the retracted position, while switches S2 and S3 remain open. The voltage Ve then drops to the voltage Vs. From time t5 onwards, the shape of the current signal I1 or I2 is symmetrical to that observed between times t1 and t4. Thus, from time t5 onwards, the current I1 or I2 increases until it reaches a value ISM1 where the magnetic force produced in the coil CL is sufficiently high to move the core PL within the coil. This displacement implies a back electromotive voltage which causes the current II or 12 to drop between instants t6 and t7.From time t7, the current II or 12 increases again until it reaches the positive threshold value ILM1 at time t8. At time t8, all switches S1-S4 are open when the measurement of the current II or 12 reaches the threshold value ILM1. From time t8, the voltage Ve in the coil CL goes to 0, while the current II or 12 falls to tend towards 0.

[0041] Thanks to these provisions, the energy required to actuate the core in the electromagnet T can be adjusted to the bare minimum by simply adjusting a threshold value. As a result, the actuator comprising such an electromagnet can exhibit reduced power consumption and, consequently, reduced heating. Since the switching times of the electromagnet T are reduced, it can be controlled at high frequencies, as in braking controls of certain aircraft. Furthermore, the electromagnet is controlled without any external sensors.

[0042] According to one embodiment, the negative threshold value -ILM2 is set to a value a few percent higher (for example, less than 10%, or between 3% and 8%) than a static current value -IST2 (or the absolute maximum) reached in the coil CL when it remains subjected to the voltage -Vs. The maximum value -IST2 can be equal to the supply voltage -Vs divided by the internal resistance Rc of the coil CL in a static state. Similarly, the positive threshold value ILM1 is set to a value a few percent lower (for example, less than 10%, or between 3% and 8%) than the static current value IST1 reached in the coil CL when it remains subjected to the voltage Vs.

[0043] According to another embodiment, the negative threshold value -ILM2 is set to a value a few percent lower (for example, less than 10%, or between 3% and 8%) than the current value -ISM2 at which the PL core in the CL coil begins to move (towards its deployed position). Similarly, the positive threshold value ILM1 is set to a value a few percent higher (for example, less than 10%, or between 3% and 8%) than the current value ISM1 at which the PL core in the CL coil begins to move (towards its retracted position).

[0044] According to another embodiment, the negative threshold value in absolute value ILM2 and the positive threshold value ILM1 are equal and fixed at a few percent (for example less than 10%, or between 3% and 8%), below the maximum static current value IST1 or IST2, or above the current value ISM1 or ISM2.

[0045] According to one embodiment, the supply voltage VS or Ve of the electromagnet's coil CL is increased to reduce the electromagnet's reaction times (between times t1 and t2, and between times t5 and t6) following the application of a deployment or retraction command (at time t1 or t5). Indeed, the threshold values ​​ILM1 and ILM2 do not depend on the supply voltage Vs or Ve of the electromagnet's coil CL. As a result, the power seen by the electromagnet varies little with the supply voltage.

[0046] According to one embodiment, the current threshold value ILM1, ILM2 is determined by the force required to move the core in the electromagnet, plus a margin of a few percent determined according to parameters of extreme external environmental conditions (in particular ambient temperature) which notably influence the current threshold values ​​ILM1, ILM2. Indeed, the movement of the core may require more or less energy depending on the ambient temperature.

[0047] The CTL control circuit can be implemented simply using an electronic circuit without computational capabilities. Figure 3 shows an example of such an implementation. The CTL control circuit comprises a comparator CPI, an EDT circuit for detecting rising or falling edges in a signal, an RS-type flip-flop FF1, an inverter-type logic gate IG1, and two AND-type logic gates AGI and AG2. The COM control signal is supplied to the input of the EDT circuit, the AG2 gate, and the inverter IGL. The output of the inverter IG1 is connected to an input of the AGI gate. The comparator CPI receives the current measurement signal II (in absolute value) or I12 on an inverting input, and the threshold value ILM1 or ILM2 on a forward input. The flip-flop FF1 receives the output signal from the EDT circuit on an input S and the output signal from the comparator CPI on an input R.A direct output Q of the flip-flop FF1 is connected to an input of gate AGI and an input of gate AG2. Gate AGI provides the control signal for switches S2 and S3, and gate AG2 provides the control signal for switches S1 and S4.

[0048] According to one embodiment, the actuator is controlled by alternating high-frequency commands, for example by PWM, in particular to obtain an adjusted flow rate in a solenoid valve. Thus, as illustrated in Figure 4, the instant t4 as described with reference to Figure 2 is followed by an instant t5' when the COM control signal transitions from state 0 to state 1, close to instant t4, that is, before the current II or 12 reaches 0 A. Between instant t5' and an instant t6', the current II or 12 follows a variation similar to that observed between instants t5 and t8 in Figure 2. The COM control signal can be inverted by transitioning to state 0 at an instant t7' just after instant t6', that is, before the current II or 12 reaches 0 A. Between instant t7' and an instant t8', the current II or 12 follows a variation similar to that observed between instants t1 and t4.Thus, the COM control signal can have pulses that can be reduced to the duration between times t5 and t8 and intervals between these pulses that can be reduced to the duration between times t1 to t4.

[0049] Furthermore, a change of state of the COM signal could occur as soon as the PL core switches to the other position (deployed / retracted), i.e. after time t2 or time t6. Such a change of state triggers the reversal of the polarity of the voltage Ve by an appropriate control of the switches SI to S4 causing the start of a sequence beginning at time t1 or t5 depending on the transition observed in the COM control signal.

[0050] Figure 5 shows an EMC1 control circuit for the electromagnet, according to another embodiment. The EMC1 control circuit comprises two switches SI1, S12, and two diodes D1, D2 connected in parallel with the switches respectively. SI1, S12, a bidirectional freewheeling diode D3, connected in parallel with the electromagnet's coil CL, a control circuit CTL1 for switches SU and S12, and a voltage generation circuit VGN providing a supply voltage Vs to coil CL. The cathode of diode DI and the cathode of diode D2 are connected to terminals B13 and B14, respectively, of coil CL. The anode of diode DI and switch SI1 are connected to the first terminal B11 of the voltage generation circuit VGN. The anode of diode D2 and switch S12 are connected to the second terminal B12 of the VGN circuit. The voltage Vs is supplied between the first and second terminals of the VGN circuit. The freewheeling diode D3 prevents voltage spikes when switches SU and S12 are opened.The EMC1 control circuit receives a current measurement signal 12 or 13 flowing in the CL coil of the electromagnet supplied by a current probe IS1 or IS2 placed on terminal B11 or B12 of the VGN circuit, or two current probes IS1, IS2 placed respectively on terminals B11, B12 of the VGN circuit.

[0051] The voltage generation circuit VGN is configured so that the supplied voltage Vs is positive or negative to reach the deployment and retraction positions, respectively, of the PL core actuated by the electromagnet. The control circuit CTL1 is configured to close switch SI1 and open switch S12 when the voltage Vs is positive, and conversely, to open switch SI1 and close switch S12 when the voltage Vs is negative. Furthermore, the control circuit CTL1 is configured to open switches SI1 and S12 when the current II in the coil CL reaches the threshold value ILM1 or ILM2.

[0052] Table 2 below indicates the state (O: open, F: closed) of the switches SU, S12 and the state (B: blocked, P: conducting) of the diodes D1, D2, as a function of time t and the polarity of the output voltage Vs of the VGN circuit, in relation to the current timing diagram of Figure 2.

[0053] [Tables2] t tO - tl tl -t2 t2 -13 t3 —14 t4 -15 t5 -16 t6 -17 t7 -18 t8 —19 Vs — + + + + — — — — SU OFFFOOOOO S12 OOOOOFFFO Dl BBBBBPPPB D2 BPPPBBBBB

[0054] When the voltage generation circuit VGN supplies a positive voltage +Vs representing a command to the deployed position of the PL core in the electromagnet, the control circuit CTL1 closes the switch SU. The current The current then passes through diode D2. The voltage Ve in coil CL is equal to Vs. When the current II in coil CL reaches the threshold value ILM2, the control circuit CTL1 opens switch SU.

[0055] When the voltage generation circuit VGN supplies a negative voltage -Vs representing a command to the retracted position of the PL core in the electromagnet, the control circuit CTL1 closes switch S12. Current then flows through diode DI. The voltage Ve in coil CL is equal to -Vs. When the current II in coil CL reaches the threshold value ILM1, the control circuit CTL1 opens switch S12.

[0056] Thus, the EMC1 control circuit controls the current II in the coil CL according to the current timing diagram II or 12 of Figure 2, the COM control signal being replaced by the voltage control Vs supplied by the voltage generation circuit VGN.

[0057] The definition of the threshold values ​​ILM1, ILM2 can be the same as in the embodiment of Figure 1.

[0058] When the switches SI 1 and S12 are each made by a transistor, the diodes DI and D2 can be part of the latter.

[0059] The CTL1 control circuit can also be implemented simply using an electronic circuit without computational capabilities. Figure 6 shows an example of such an implementation of the CTL1 control circuit. The CTL1 control circuit comprises two comparators, CP2 and CP3, a polarity detection PDT circuit to detect the polarity of the voltage Vs supplied by the generator VGN, an RS-type flip-flop FF2, an inverter-type logic gate IG2, and two AND-type logic gates, AG3 and AG4. The voltage Vs generated by the VGN circuit is supplied to the input of the PDT circuit and to the direct input of comparator CP3, whose inverting input is connected to ground. The output signal of comparator CP3 is supplied to the input of gate AG4 and inverter IG2. The output of inverter IG2 is connected to an input of gate AG3.Comparator CP2 receives the current measurement signal II (in absolute value) or 12 (or 13) on an inverting input, and the threshold value ILM1 or ILM2 on a direct input. Flip-flop FF2 receives the output signal from the PDT circuit on an input S and the output signal from comparator CP2 on an input R. A direct output Q of flip-flop FF2 is connected to an input of gate AG3 and an input of gate AG4. Gate AG3 provides the control signal for switch S12, and gate AG4 provides the control signal for switch SL.

[0060] Figures 7A and 7B show a classic example of a bistable solenoid valve. The solenoid valve comprises a body BY having an axial channel CH that can be hermetically sealed by a shutter OB in cooperation with a seal TJ. The solenoid valve includes a coupled bistable electromagnetic actuator The actuator mechanically moves the shutter OB to place it either in a closed position, as illustrated in Figure 7A, or in an open position, as illustrated in Figure 7B. The actuator comprises an electromagnet and a ferromagnetic core PL, which is integral with the shutter OB. The electromagnet includes one or more coils CL1, CL2, and optionally one or more permanent magnets PMI, PM2. The coils CL1 and CL2 surround the core PL and the permanent magnets PM. The core PL is movable between two stable positions where it can abut against damping blocks DB. The two stable positions of the core PL correspond to the open and closed positions of the shutter OB. The entire assembly of the channel CH, the shutter OB, the coils CL1 and CL2, the permanent magnets PMI and PM2, and the blocks DB is generally cylindrical in shape.The permanent magnets PMI, PM2 help to maintain the PL core in its two stable positions, particularly when the CL1, CL2 coils are not energized.

[0061] It will be evident to those skilled in the art that the present invention is susceptible to various embodiments and applications. In particular, the invention is not limited to the previously described examples of electromagnet control circuits. Indeed, other control circuits can easily be developed to control the electromagnet based on an external command and the comparison of the current flowing in the electromagnet coil to the threshold values ​​described above.

[0062] Furthermore, the actuator described above can be implemented in devices other than a solenoid valve. Such an actuator can be used, for example, in an electronic lock or, more generally, a locking system, or even in electrical switching devices such as relays and circuit breakers.

[0063] Furthermore, the invention is not limited to solenoid valves used in aircraft braking systems. Such a solenoid valve can be used in other systems, such as medical systems or more generally in air or water flow control systems.

Claims

Demands

1. 1. A method for controlling a bistable electromagnetic actuator comprising steps of: upon receiving a command (COM, Vs) to transition between two stable positions of the actuator, subjecting an electromagnet coil (CL, CL1, CL2) of the actuator to a first voltage (Ve) capable of moving a core (PL) of the actuator and monitoring a current (II, 12, 13) passing through the electromagnet coil, and when the current in the electromagnet coil crosses a threshold value (ILM1, -ILM2) greater in absolute value than a minimum value (ISM1, -ISM2) of current to be supplied to the electromagnet to move the core, placing the electromagnet coil off.

2. 2. A method according to claim 1, wherein the absolute threshold value (ILM1, ILM2) is set at less than 20%, and preferably less than 10% above the minimum value (ISM1, ISM2) of current to be supplied to the electromagnet to move the core, or at less than 20%, and preferably less than 10% below a maximum value (IST1, IST2) of static current reached in the electromagnet coil when the electromagnet coil is subjected to the first voltage.

3. 3. A method according to claim 1 or 2, wherein the threshold value (ILM1, -ILM2) depends on the polarity of the first voltage (Ve), and wherein: when the first voltage has a positive polarity, the threshold value (ILM1) is set at less than 10% above a first minimum value (ISM1) of the current to be supplied to the electromagnet to move the core, or at less than 10% below a first maximum value (IST1) of the static current reached in the electromagnet coil when the electromagnet coil is subjected to the first voltage; and when the first voltage has a negative polarity, the threshold value (-ILM2) is set at less than 10% below a second maximum value (-ISM2) of the current to be supplied to the electromagnet to move the core, or at less than 10% above a second minimum value (-IST2) of the static current reached in the coil. of electromagnet when the electromagnet coil is subjected to the first voltage.

4. 4. A method according to any one of claims 1 to 3, wherein the absolute threshold value (ILM1, ILM2) is fixed at the minimum value (ISM1, ISM2) of current to be supplied to the electromagnet to move the core, plus a margin determined according to parameters of extreme external environmental conditions of the actuator.

5. 5. A method according to any one of claims 1 to 4, wherein the command is received in the form of a change of state of a two-state control signal (COM), the state of the control signal determining a polarity of the first voltage (Ve) to which the electromagnet coil is subjected.

6. 6. A method according to any one of claims 1 to 4, wherein the command is received in the form of a polarity reversal of a supply voltage (Vs) corresponding to the first voltage (Ve) to which the electromagnet coil is subjected.

7. 7. Bistable electromagnetic actuator comprising: an electromagnet coil, a moving core actuated by the electromagnet, and an electromagnet control circuit configured to implement the method according to any one of claims 1 to 6.

8. 8. Solenoid valve controlled by an actuator according to claim 7.

9. 9. Aircraft braking system, comprising a solenoid valve according to claim 8.

10. 10. Aircraft comprising a braking system according to claim 9.

Images