A control apparatus includes a constant storage portion that stores constant values of an electromagnet coil including a resistance value Rm, an inductance Lm, a sampling time Ts, etc. A current storage portion stores previous current command values Ir having been regularly sampled by a microcomputer inside a current control circuit. A low-frequency feedback circuit generates a signal for suppressing an error between DC components and low-frequency components of an input current command value Ir and a detected current value IL and outputs the signal. An output voltage computing circuit calculates, based on the input current command value Ir[n+1], a stored value Ir[n] of the current storage portion, a stored value of a constant storage portion, and the signal of the low-frequency feedback circuit, a voltage for suppling the electromagnet coil with a current in accordance with a command, and outputs the calculated voltage.

A magnetic bearing device comprises a stator (30) and a rotor (10) supported in the stator for rotation around a rotation axis (R). The rotor comprises at least one permanent magnet (21, 22) that is magnetized along the rotation axis. The stator comprises at least one closed magnetic core (31) that surrounds the rotor (10) and at least one radial bearing winding (32) arranged on the closed magnetic core (31) in a toroidal configuration. The at least one radial bearing winding is arranged to interact with a permanent magnetic field generated by the at least one permanent magnet to obtain a radial bearing force when current is supplied to the at least one radial bearing winding.

An electric motor system includes a rotary shaft having an axis line displaceable relative to a rotation center, a magnetic bearing for supporting the rotary shaft, a permanent magnet mounted on the rotary shaft and having a plurality of magnetic poles arranged in a circumferential direction around the axis line of the rotary shaft, three detection elements arranged in the circumferential direction around the rotation center for detecting a magnetic flux generated from the permanent magnet, and a coordinate detection section for determining coordinates of the axis line of the rotary shaft based on output values of two detection elements selected out of the three detection elements in accordance with a rotation angle of the rotary shaft.

A thrust magnetic bearing includes a stator having a coil that produces a magnetic flux, and a rotor. The magnetic flux supports the rotor in a non-contact manner. The stator has main and auxiliary stator magnetic pole surfaces. The rotor has main and auxiliary rotor magnetic pole surfaces. The main and auxiliary rotor magnetic pole surfaces face the main and auxiliary stator magnetic pole surfaces. The auxiliary stator magnetic pole surface includes at least one first stator surface and at least one second stator surface, alternately arranged. The auxiliary rotor magnetic pole surface includes at least one first rotor surface, and at least one second rotor surface, alternately arranged. Nr≥1 and Nt≥2, with Nr representing a number of pairs of the first stator and rotor surfaces facing each other, and Nt representing a number of pairs of the second stator and rotor surfaces facing each other.

A thrust magnetic bearing includes a stator having a coil that produces a magnetic flux, and a rotor. The magnetic flux supports the rotor in a non-contact manner. The stator has main and auxiliary stator magnetic pole surfaces. The rotor has main and auxiliary rotor magnetic pole surfaces. The main and auxiliary rotor magnetic pole surfaces face the main and auxiliary stator magnetic pole surfaces. The auxiliary stator magnetic pole surface includes at least one first stator surface and at least one second stator surface, alternately arranged. The auxiliary rotor magnetic pole surface includes at least one first rotor surface, and at least one second rotor surface, alternately arranged. Nr≥1 and Nt≥2, with Nr representing a number of pairs of the first stator and rotor surfaces facing each other, and Nt representing a number of pairs of the second stator and rotor surfaces facing each other.

A magnetic bearing control apparatus includes a plurality of output elements configured to generate electromagnetic force, a magnetic bearing configured to float a rotation shaft from a surface of the magnetic bearing based on the electromagnetic force generated by the plurality of output elements, at least one displacement sensor configured to sense a displacement of the rotation shaft, and a controller. The controller is configured to control a current supplied to the plurality of output elements, to control a position of the rotation shaft based on the current supplied to the plurality of output elements according to the displacement of the rotation shaft, and to determine a failure of the displacement sensor.

A rotor, a magnetic bearing, and a drive unit that rotationally drives the rotor. The magnetic bearing includes a bearing stator and a ring-shaped bearing rotor member. The drive unit has a drive stator and a ring-shaped drive rotor member. The bearing stator has a plurality of bearing stator cores consisting of a magnetic material, disposed on an outer peripheral side of the bearing rotor member. The bearing stator core has a first portion extending in a first direction orthogonal to a direction facing the bearing rotor member, and a pair of second portions extending to a bearing rotor member side from both end portions in the first direction of the first portion. The drive stator is formed so as to pass through a position between an outer peripheral surface of the rotor and the first portion core and between the pair of second portions.

A track element of a non-contact bearing extending in a length direction. The track element includes a conductive material strip having a facing surface with a height and width and a rear surface opposite the facing surfaces. The conductive material strip includes a slit extending in a height direction to form a first leg and a second leg, in which the first leg is bent in a zig-zag shape and the second leg is bent in a zig-zag shape that is complementary to the bending of the first leg. When the conductive material strip is viewed in a direction parallel to the facing surface, the first leg and the second leg cross each other at least once.

A magnetic bearing contactlessly supporting a rotor by magnetic force includes: a bearing rotor member made of a magnetic material; and a bearing stator member arranged around bearing rotor member. The bearing stator member includes a core made of a magnetic material and a coil wound around the core. A longitudinal cross-sectional shape of the core has a first part extending in a first direction orthogonal to a direction opposed to the bearing rotor member and wound around with the coil, a pair of second parts extending from both end portions in the first direction of first part to the bearing rotor member side and subsequently extending in a direction approaching each other in the first direction, and a pair of third parts extending from respective distal end portions of the pair of second parts toward the bearing rotor member side. The bearing rotor member also includes a permanent magnet.

The present disclosure relates to a stiffness enhancing mechanism for a magnetic suspension bearing, a magnetic suspension bearing including the stiffness enhancing mechanism, and a blood pump. The magnetic suspension bearing comprises a stator with stator teeth and a rotor disposed within the stator. The stiffness enhancing mechanism comprises: a rotor permanent magnet, a stator permanent magnet, and an axial driving body. The rotor permanent magnet and the rotor of the magnetic suspension bearing form a rotor assembly, which has an asymmetric structure with respect to the main plane (P) of the rotor. The stiffness enhancing mechanism is configured such that the stator permanent magnet generates a radial attractive force to the rotor permanent magnet, and the axial driving body generates an axial repulsive force to the rotor permanent magnet, wherein the magnitude of the axial repulsive force is variable with a change of an axial distance between the axial driving body and the rotor permanent magnet). The stiffness enhancing mechanism can increase the torsional stiffness of the rotor of the magnetic suspension bearing and facilitate the miniaturization of the magnetic suspension bearing.