A method for constructing an active magnetic bearing controller based on a look-up table method includes: building finite element models of an active magnetic bearing to obtain two universal Kriging prediction models in X-axis and Y-axis directions about actual suspension forces being in association with actual displacement eccentricities and actual control currents in the X-axis and Y-axis directions of the active magnetic bearing based on a universal Kriging model; creating two model state tables in the X-axis and Y-axis directions about the actual suspension forces being in association with the actual displacement eccentricities and the actual control currents to construct two look-up table modules with the two built-in model state tables, respectively; and constructing an active magnetic bearing controller by using two fuzzy adaptive PID controllers, two amplifier modules in the X-axis and Y-axis directions, the two look-up table modules, and two measurement modules in the X-axis and Y-axis directions.

A magnetic bearing controller for controlling a magnetic levitation motor, the magnetic levitation motor including: a rotor; a pair of electromagnets that causes the rotor to levitate by electromagnetic force; an auxiliary bearing that supports a rotating shaft of the rotor when the rotor is stopped; and a rotor position detector that detects the rotor's position in a levitation direction. The magnetic bearing controller includes an operation current generator that generates an operation current value corresponding to a deviation between a position command value and the rotor's position detected by the rotor position detector. The operation current generator is configured to give a predetermined initial value greater than 0 to the operation current value at a start of levitation for causing the rotor in a state where the rotating shaft of the rotor is supported by the auxiliary bearing to levitate and be positioned at a predetermined target position.

System for controlling at least one active magnetic bearing equipping a rotating machine comprising a rotor and a stator, at least one means for measuring the radial positions of the rotor as a function of the signal from at least one position sensor, and at least two control loops of the active magnetic bearing as a function of the radial positions of the rotor, each control loop of the magnetic bearing being provided with at least one synchronous filter as a function of the rotation speed, and an extended Kalman filter for determining the rotation speed of the rotor with respect to the stator receiving as input, from position sensors, measurements of radial position of the rotor and as a function of measurements of radial position of the rotor performed over a predetermined time at zero rotor rotation speed.

A magnetic levitation control device comprises: a control signal generation section configured to generate a first excitation current control signal based on current deviation information on the excitation current detection signal with respect to the current setting signal and a second excitation current control signal based on the current setting signal; and a selection section including a first switching section configured to select either one of the first excitation current control signal or the second excitation current control signal or a second switching section configured to select either one of a third excitation current control signal obtained by summation of the first excitation current control signal and the second excitation current control signal or the second excitation current control signal. The excitation amplifier is PWM-controlled based on the excitation current control signal selected by the selection section.

An electronic device is provided. The electronic device includes a flexible screen and a housing. The housing includes a first frame, a second frame, and a bendable device. The bendable device is connected between the first frame and the second frame. The flexible screen is disposed on the first frame, the second frame, and the bendable device. The bendable device is used to support the flexible screen disposed on the housing. The bendable device includes a first part, a second part, and a third part. The first part is rotatably connected with the second part via a first rotating shaft. The first part is rotatably connected with the third part via a second rotating shaft. A housing and a bendable device of the electronic device are also provided in the disclosure.

A bendable assembly (10) including a hinge module (12) and a linkage module (14). The hinge module (12) includes a first connecting hinge (122) and a second connecting hinge (124) respectively disposed at two opposite sides of the hinge module (12). The linkage module (14) is connected and arranged between the first connecting hinge (122) and the second connecting hinge (124). When the first connecting hinge (122) rotates, the linkage module (14) transmits a rotation of the first connecting hinge (122) to the second connecting hinge (124) to drive the second connecting hinge (124) to rotate. Operation convenience in state switching of the bendable assembly (10) and a flexible display device (100) can be realized, and user experience is improved.

A downhole-type system includes a rotatable rotor, a magnetic thrust bearing coupled to the rotor, and a mechanical thrust bearing coupled to the rotor. The magnetic thrust bearing is configured to support a first portion of an axial load of the rotor during rotor rotation, and the mechanical thrust bearing is configured to support a second portion of the axial load of the rotor during rotor rotation.

A fluid rotor is configured to move or be rotated by a working fluid. A fluid stator surrounds the fluid rotor. The fluid stator is spaced from the fluid rotor and defines a first annular fluid gap in-between that is in fluid communication with an outside environment exterior the downhole-type pump. A radial magnetic bearing includes a first portion coupled to the fluid rotor and a second portion coupled to the fluid stator. The first portion is spaced from the second portion defining a second annular fluid gap in-between that is in fluid communication with the outside environment exterior the downhole-type pump.

A system to provide power to a downhole-type tool includes a downhole-type electric motor that can be positioned in a wellbore and a variable speed drive electrically connected to the electric motor, in which the downhole-type electric motor can operate at rotary speeds of at least 6,000 rotations per minute (rpm), the variable speed drive can control and supply power to the electric motor when the electric motor is positioned at a downhole location inside the wellbore, and the variable speed drive can be at a surface of the wellbore.

A tool includes a device including a housing and a rotor, the rotor to rotate about a longitudinal axis, and an axial gap generator including a stator assembly positioned adjacent to the rotor. The axial gap generator generates a voltage signal as a function of a gap spacing between the stator assembly and the rotor, the gap spacing being parallel to the longitudinal axis.