摘要:
An active magnetic bearing (100) with autodetection of position, the bearing comprising at least first and second opposing electromagnets (120, 130) forming stators disposed on either side of a ferromagnetic body (110) forming a rotor and held without contact between said electromagnets. The first and second electromagnets (120, 130) each comprising a magnetic circuit (121; 131) essentially constituted by a first ferromagnetic material and co-operating with said ferromagnetic body to define an airgap, together with an excitation coil (122; 132) powered from a power amplifier whose input current is servo-controlled as a function of the position of the ferromagnetic body relative to the magnetic circuits of the first and second electromagnets. The position of the ferromagnetic body (110) being measured from the inductance detected between the two electromagnets (120, 130) in response to simultaneous injection into both opposing electromagnets of a sinusoidal current at a frequency that is greater than the closed loop passband of the system. The magnetic circuit (121; 131) of each electromagnet further includes a portion (124; 134) in the vicinity of the excitation coil (122; 132) that uses a second ferromagnetic material having magnetic permeability that is lower than that of the first material and electrical resistivity that is higher than that of the first material so as to encourage the passage of the high frequency magnetic fields that are generated in the bearing.
摘要:
The rotary machine comprises a rotary shaft (2) supported by first and second radial magnetic bearings (5, 6) that are electrically controlled by a control device (13), said rotary shaft being fitted with an axial abutment device (100) comprising a rotor formed by a disk (101) secured to the rotary shaft (2) and interposed between first and second stators (102, 104) formed annularly around the rotary shaft and each including at least one annular coil (103; 105) controlled electrically by a system for servo-controlling the axial position of the rotary shaft. The stator (104) of the axial abutment device (100) further comprises a secondary induction circuit (106), and the disk (101) secured to the rotary shaft comprises a primary induction circuit (107) so that during rotation of the shaft, electricity is excited in the secondary induction circuit in order to supply energy to the radial magnetic bearings.
摘要:
An active magnetic bearing (100) with autodetection of position, the bearing comprising at least first and second opposing electromagnets (120, 130) forming stators disposed on either side of a ferromagnetic body (110) forming a rotor and held without contact between said electromagnets. The first and second electromagnets (120, 130) each comprising a magnetic circuit (121; 131) essentially constituted by a first ferromagnetic material and co-operating with said ferromagnetic body to define an airgap, together with an excitation coil (122; 132) powered from a power amplifier whose input current is servo-controlled as a function of the position of the ferromagnetic body relative to the magnetic circuits of the first and second electromagnets. The position of the ferromagnetic body (110) being measured from the inductance detected between the two electromagnets (120, 130) in response to simultaneous injection into both opposing electromagnets of a sinusoidal current at a frequency that is greater than the closed loop passband of the system. The magnetic circuit (121; 131) of each electromagnet further includes a portion (124; 134) in the vicinity of the excitation coil (122; 132) that uses a second ferromagnetic material having magnetic permeability that is lower than that of the first material and electrical resistivity that is higher than that of the first material so as to encourage the passage of the high frequency magnetic fields that are generated in the bearing.
摘要:
The flexibly-mounted turbomolecular pump comprises a leaktight casing mounted on a structure via a mechanical damper, a vertical support driven by an electric motor, radial magnetic bearings, an axial magnetic bearing, radial detectors, an axial detector, an emergency mechanical bearing, and a control module comprising power supply circuits and servo-control circuits for the axial and radial magnetic bearings. The servo-control circuits present low stiffness and include filter circuits for defining a limited passband. The control module comprises a comparator unit for detecting abnormally large movements of the rotor from signals delivered by the axial and radial detectors, which movements are greater than predetermined thresholds. The servo-control circuits include a restabilization network and a unit for selectively activating the restabilization network during a predetermined duration after a time at which the crossing of at least one of the predetermined thresholds is detected during a movement of the rotor.
摘要:
The present invention provides a circuit for monitoring harmonic distortion in the power supply of a synchronous electrical machine with permanent magnet excitation that comprises a rotor without a damper cage, a stator with first, second, and third windings, a frequency converter, and control circuits for controlling the frequency converter. The monitoring circuit comprises means for obtaining at least one signal representative of the current in the first winding of the stator and at least one signal representative of the current in the second winding of the stator; a circuit for generating synchronizing pulses reflecting the electrical frequency fn of rotation of the rotor relative to the stator; means for determining a signal representative of the current in the third winding of the stator; a set of band-stop notch filters respectively receiving said signals representative of the currents in the first, second, and third windings, and each presenting a center frequency that is servo-controlled to the electrical frequency fn of rotation of the rotor, in order to reject the harmonic corresponding to said electrical frequency fn; a set of measurement circuits for measuring the harmonics that remain in the signals output by each of the band-stop notch filters; and a comparator circuit for continuously comparing the greatest of the values of the signals from the measurement circuits relative to an alarm threshold.
摘要:
An active magnetic bearing with auto position-detection includes first and second opposing electromagnets disposed on opposite sides of a ferromagnetic body (1) suspended without contract with the electromagnets. The bearing includes inductive type position detectors which are constituted directly by coils (11, 21) of the first and second electromagnets. A mechanism (14; 24) is provided for injecting a sinusoidal current I.sub.0 sin.omega.t of constant amplitude I.sub.0, of angular frequency .omega., and of identical phase, simultaneously to the inputs of power amplifiers (13, 23) powering the coils (11, 21) of the first and second opposing electromagnets in superposition with the main currents from the servo-control circuits (31, 32). Circuits (41 to 44) serve to extract the position information which determines the magnitude of the main current to be applied by the servo-control circuits (31, 32) to the power amplifiers (13, 23) directly from the voltages u.sub.1, u.sub.2 across the terminals of the excitation coils (11, 21) as measured at the frequency of the sinusoidal current constituting a carrier of angular frequency .omega..
摘要:
The present invention provides a circuit for monitoring harmonic distortion in the power supply of a synchronous electrical machine with permanent magnet excitation that comprises a rotor without a damper cage, a stator with first, second, and third windings, a frequency converter, and control circuits for controlling the frequency converter. The monitoring circuit comprises means for obtaining at least one signal representative of the current in the first winding of the stator and at least one signal representative of the current in the second winding of the stator; a circuit for generating synchronizing pulses reflecting the electrical frequency fn of rotation of the rotor relative to the stator; means for determining a signal representative of the current in the third winding of the stator; a set of band-stop notch filters respectively receiving said signals representative of the currents in the first, second, and third windings, and each presenting a center frequency that is servo-controlled to the electrical frequency fn of rotation of the rotor, in order to reject the harmonic corresponding to said electrical frequency fn; a set of measurement circuits for measuring the harmonics that remain in the signals output by each of the band-stop notch filters; and a comparator circuit for continuously comparing the greatest of the values of the signals from the measurement circuits relative to an alarm threshold.
摘要:
The active magnetic bearing (1) comprises a stator (2) fitted with electromagnet windings (21) and a first stack of ferromagnetic laminations (22), a rotor (3) fitted with a second stack of ferromagnetic laminations (9), servo-control circuits (10), and position detectors (4, 5, 6). The first stack of ferromagnetic laminations (22) comprises in succession in the axial direction: at least a first sub-set (2a) of laminations (22a) presenting first notches housing electromagnet windings (21); a second sub-set (2b) of laminations (22b) presenting both first notches housing electromagnet windings (21) and second notches housing a radial detector (6); and a third sub-set (2a) of laminations (22a) presenting first notches housing electromagnet windings (21). The first stack of ferromagnetic laminations (22) further comprises fourth and fifth sub-sets (2c) of laminations (22c) at its ends, presenting the same notches as each other and housing respective first and second axial detectors (4, 5).
摘要:
A high speed energy storage flywheel comprises a rotor which is located in a vacuum chamber provided in a stator housing and is supported by magnetic bearings with respect to the stator housing. A fluid tank used for releasing in a controlled manner, a fluid inside the vacuum chamber and therefore create a braking effect on the rotor by friction.
摘要:
A device for detecting the axial position of a rotary shaft of a rotary machine comprises a target of ferromagnetic material placed at the end of the rotary shaft, an induction coil associated with a stationary magnetic circuit and placed facing the target while leaving an airgap, and a power supply circuit. The power supply circuit comprises an AC voltage source connected between a first end of the induction coil and a zone situated at a reference voltage, at least one capacitor connected between the ends of the induction coil, and a detector device interposed between a second end of the induction coil and the zone situated at the reference voltage, in order to deliver on a line information about the magnitude of the current flowing between the second end and the zone situated at the reference voltage.