Abstract: A piezoelectric device comprises a fixed frame and a mirror carrier defining several support points securing a mirror. The mirror carrier is mounted rotatable. Several piezoelectric actuators are fixed to the support and deform independently in translation in a first direction. Each piezoelectric actuator moves the support area of the mirror carrier. The mirror carrier defines several attachment points. Each attachment point connects the mirror carrier mechanically with a piezoelectric actuator. The support points and attachment points are distinct from one another. The mirror carrier defines a plurality of flexion areas. The support points are movable with respect to one another. The piezoelectric actuators supplied in push-pull mode drive the support points making the mirror rotate perpendicularly to the first direction.

Abstract: The actuator comprises a movable armature swivelling with respect to a stator provided with flanges on which magnets are fitted and a coil fitted around one of the flanges. The magnets have an axial magnetisation in a z axis and are aligned in an x axis. The movable armature is arranged between the magnets in the x axis. The movable armature is mounted on a guide imposing swivelling around a y axis perpendicular to the x and z axes. The movable armature is separated from the magnets by air-gaps. Each magnet forms a static magnetic circuit with one end of the movable armature and one of the flanges. The coil forms a dynamic magnetic circuit with the ends of the movable armature and the flanges.

Abstract: The actuator comprises a movable armature swivelling with respect to a stator provided with flanges on which magnets are fitted and a coil fitted around one of the flanges. The magnets have an axial magnetisation in a z axis and are aligned in an x axis. The movable armature is arranged between the magnets in the x axis. The movable armature is mounted on a guide imposing swivelling around a y axis perpendicular to the x and z axes. The movable armature is separated from the magnets by air-gaps. Each magnet forms a static magnetic circuit with one end of the movable armature and one of the flanges. The coil forms a dynamic magnetic circuit with the ends of the movable armature and the flanges.

Abstract: A device for filling a tank with a pressurized gas, in particular with pressurized hydrogen, comprising a pressurized-gas source and a circuit for transferring gas from the source to the tank, the transfer circuit including a member for expanding and cooling the gas in order to lower the pressure and temperature of the gas from the source to respective values determined with a view to filling the tank, characterized in that the gas-expansion and cooling member includes a refrigerator that expands the gas by means of a Stirling or Ericsson thermodynamic cycle, the refrigerator being selectively supplied with gas from the source, and in that at least a portion of the cooled and expanded gas supplied to the tank is extracted from the refrigerator.

Abstract: A method for the pulsating load refrigeration of a component of a Tokamak using a refrigeration device subjecting a working fluid to a working cycle. At least one “periodic and symmetrical” operating mode of the Tokamak includes an operating mode in which plasmas of preset duration Dp are generated periodically with intervals of duration Dnp between two successive plasmas. Dnp=Dp±30%. The cooling device cooling power is increased to a relatively high level in a plasma generation phase and reduced to a relatively low level when the Tokamak is no longer in a plasma generation phase. The refrigerating power variation brings gradual increases and reductions in refrigerating power. The increase in the refrigeration device refrigerating power is triggered in advance, in response to a signal (S) generated during a plasma starting step before the thermal load on the component increases.

Abstract: The invention relates to a method and device for pulsed charge cooling of a component of a Tokamak. The method uses a refrigeration device that subjects a working fluid such as helium to a work cycle including: compression, cooling, and decompression, as well as heat exchange with the member and heating. The refrigeration power produced by the refrigeration device is increased to a relatively high level when the Tokamak is in a plasma generation phase and is decreased to a relatively low level when the Tokamak is no longer in a plasma generation phase. The increase in refrigeration power produced by the refrigeration device is automatically triggered in response to a signal produced during a step for starting plasma in the Tokamak.

Abstract: A linear electrodynamic-type motor, for compressing a fluid circulating in a cryocooler notably using a Stirling cycle, includes a translationally movable induction coil; a power-supply circuit adapted to deliver, to at least one induction coil, an AC power-supply current; a movable mass adopting a translational movement; an induction coil arranged so as to move a respective movable mass between a first position and a second position where the movable mass can compress the fluid; and a secondary circuit arranged to connect the terminals of at least one induction coil in short-circuit. The secondary circuit comprises a compensation component for producing a phase shift between the power-supply voltage and the power-supply current, so as to reduce the phase difference that the inductance of the induction coil produces.

Abstract: A device for filling a tank with a pressurized gas, in particular with pressurized hydrogen, comprising a pressurized-gas source and a circuit for transferring gas from the source to the tank, the transfer circuit including a member for expanding and cooling the gas in order to lower the pressure and temperature of the gas from the source to respective values determined with a view to filling the tank, characterized in that the gas-expansion and cooling member includes a refrigerator that expands the gas by means of a Stirling or Ericsson thermodynamic cycle, the refrigerator being selectively supplied with gas from the source, and in that at least a portion of the cooled and expanded gas supplied to the tank is extracted from the refrigerator.

Abstract: The motion of the magnetized movable masses of a bilinear electrodynamic motor comprising two movable masses moving in opposite senses parallel to the axis (x-x) of the motor is balanced. At least one first magnetic sensor and at least one second magnetic sensor are provided which are able to deliver respectively a first electrical signal (s1(t)) and a second electrical signal (s2(t)) respectively representative of the motion of a first and of a second movable mass. An error signal (?s(t)) equal to the difference between the said first (s1(t)) and second (s2(t)) electrical signals is recorded. A harmonic analysis of the error signal performed. A sinusoidal excitation signal (e1(t)) at a given frequency f0 is applied to the first movable mass.

Abstract: The invention relates to a method for absorbing the displacement, under the influence of an external force, of at least one plunger (10,20) in a linear electrodynamic motor comprising a least an induction coil (11, 21) magnetically coupled with the plunger. Said method comprises the steps of: detecting in said induction coil a current induced (I?ind) amplified relative to the induced current. The invention can be applied to cryogenic machines on board space ships.

Abstract: A method for the pulsating load refrigeration of a component of a Tokamak, said method using a refrigeration device subjecting a working fluid such as helium to a working cycle, the Tokamak comprising at least one operating mode called “periodic and symmetrical,” according to the method, the refrigerating power produced by the refrigeration device being increased to a relatively high level when the Tokamak is in a plasma generating phase (Dp) whereas the refrigerating power produced by the refrigeration device is reduced to a relatively low level when the Tokamak is no longer in a plasma generating phase (Dnp), characterized in that during the “periodic and symmetrical” operating phase of the Tokamak, the refrigerating power of the refrigeration device is regulated according to a forced variation also of the “periodic and symmetrical” type, that is one wherein the respective durations of generation of a high level of refrigeration and of generation of a low level of refrigerating power differ at most by 30%,

Abstract: The invention relates to a method and device for pulsed charge refrigeration of a member from a Tokamak. The method uses a refrigeration device that subjects a working fluid such as helium to a work cycle comprising: compression, cooling, and decompression, as well as heat exchange with the member and heating. The refrigeration power produced by the refrigeration device is increased to a relatively high level when the Tokamak is in a plasma generation phase, and the refrigeration power produced by the refrigeration device is decreased to a relatively low level when the Tokamak is no longer in a plasma generation phase. Said method is characterized in that the increase in refrigeration power produced by the refrigeration device is automatically triggered in response to a signal produced during a step for starting plasma in the Tokamak.

Abstract: This motor includes: a translationally movable induction coil; a power-supply circuit adapted to deliver, to at least one induction coil, an AC power-supply current; a movable mass adopting a translational movement an induction coil arranged so as to move a respective movable mass between a first position and a second position where the movable mass can compress the fluid; a secondary circuit arranged to connect the terminals of at least one induction coil in short-circuit; The secondary circuit comprises a compensation component for producing a phase shift between the power-supply voltage and the power-supply current, so as to reduce the phase difference that the inductance of the induction coil produces.

Abstract: Method for balancing the motion of the magnetized movable masses of a bilinear electrodynamic motor comprising two movable masses moving in opposite senses parallel to the axis (x-x) of the motor, characterized in that the said method comprises the steps of: providing at least one first magnetic sensor and at least one second magnetic sensor which are able to deliver respectively a first electrical signal (s1(t)) and a second electrical signal (s2(t)) respectively representative of the motion of a first and of a second movable mass, recording an error signal (?s(t)) equal to the difference between the said first (s1(t)) and second (s2(t)) electrical signals and performing a harmonic analysis of the said error signal, applying a sinusoidal excitation signal (e1(t)) at a given frequency f0 to the first movable mass, iteratively applying N successive excitation signals (e2n(t)) to the second movable mass, an excitation signal of rank n (0?n?N?1) being equal to a Fourier series of order n of fundamental freque

Abstract: The invention relates to a method for absorbing the displacement, under the influence of an external force, of at least one plunger (10,20) in a linear electrodynamic motor comprising a least an induction coil (11, 21) magnetically coupled with the plunger. Said method comprises the steps of: detecting in said induction coil a current induced (I?ind) amplified relative to the induced current. The invention can be applied to cryogenic machines on board space ships.