Skf Magnetic Mechatronics

Olivier Lemarchand

Maurice L Brunet

Joaquim Da Silva

Ulrich Schroeder

Lakdar Sadi-Haddad

Lateb Ramdane

Erwan Salahun

Yves Dupuis

Bertrand Haffray

Joaquim Dasilva

A hybrid magnetic suspension of a rotor () having compressor wheels () having permanent magnets () integral to shrunk fit rings () arranged on the rotor () in the vicinity of the compressor wheels (), permanent magnets () integral to stationary rings () coaxially arranged with the rotor () and associated with a resilient material () to define a passive radial magnetic bearing, coils () associated with magnetic armatures () and facing rotor parts () being located perpendicularly to the rotor (), and axial sensors () configured for sensing the axial position of the rotor () and control means () configured for feeding the coils () as a function of the outputs of the axial sensors () for generating both axial bearing forces and a motor torque and thereby being adapted for defining an axial bearingless motor.

Hybrid magnetic suspension of a rotor

A position detection device of active magnetic bearings (AMB's) maintaining the position of a rotating shaft and comprising two sensing inductance coils, the position detection device comprising a programmable digital component for generating a 25 KHz square waveform signal, a current amplifier receiving the 25 KHz square waveform signal and injecting two identical control currents in the two sensing inductance coils, a differential amplifier for amplifying a voltage difference between the resulting voltages in the two sensing inductance coils and, depending on the displacement of the rotating shaft, an analog to digital (A/D) converter for delivering a position value from the voltage difference.

Position detection device of AMB

A digital nonlinear corrector of an active magnetic bearing receiving an input signal x(t) and outputting an output control signal u(t) for controlling the position of said active magnetic bearing, the input signal being digitalized by a ADC circuit and provided to an adder, the digital nonlinear corrector comprising a closed control loop delivering an intermediary sequence of numbers y[kT] and having a direct branch comprising a first proportional gain circuit and a feedback branch comprising a series connection of a low-pass filter and a dead zone circuit, such that said low-pass filter is activated when determined upper and lower values of said output control signal are reached, the output control signal reproducing the input signal when these determined upper and lower values are not reached.

Digital nonlinear corrector for active magnetic bearings

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Guichainville, France

Olivier Lemarchand