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.

The disclosure is related to a flywheel energy storage system comprising a casing, a shaft, a flywheel, and at least one electric motor assembly. The shaft is rotatably disposed in the casing. The flywheel comprises a hub and an annular part, the shaft is disposed through the annular part, the annular part is fixed to the shaft via the hub, and the annular part has at least one cavity. The electric motor assembly is accommodated in the cavity and comprises a first motor rotor and a motor stator. In the cavity, the first motor rotor is fixed on the shaft, and the motor stator is fixed to the casing and located between the first motor rotor and the annular part.

A magnetic bearing control device is configured to detect, by a sensor, excitation current supplied from an excitation amplifier to a magnetic bearing configured to magnetically levitate a rotor, thereby generating a voltage equivalent signal for PWM control of the excitation amplifier based on a current setting signal based on a deviation of a rotor levitation position with respect to a target levitation position and an excitation current detection signal of the sensor. The voltage equivalent signal is generated based on the current setting signal and a current deviation signal as a difference between the current setting signal and the excitation current detection signal.

Unique systems, methods, techniques and apparatuses of active magnetic bearing control systems are disclosed. One exemplary embodiment is a power converter electrically coupled to an active magnetic bearing (AMB) having a plurality of windings, the power converter comprising a DC bus, two capacitors, a first leg, a second leg, and a controller. The capacitors are electrically coupled in series between the positive rail and negative rail, one capacitor being electrically coupled to the other capacitor at a midpoint connection. The first leg comprises a first semiconductor switching device and a first output node. The second leg comprises a second semiconductor switching device and a second output node. The first output node is electrically coupled to the midpoint connection by way of a first AMB winding and the second output node is electrically coupled to the midpoint connection by way of a second AMB winding.

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.

An electronic magnetic bearing fault-tolerant drive module includes a first plurality of switching elements and a second plurality of switching elements. At least one winding is interposed between the first plurality of switching elements and the second plurality of switching elements. The first and second switching elements are configured to selectively operate in a first mode and a second mode to generate an electromagnetic field. The electronic magnetic bearing fault-tolerant drive module is configured to detect one or more electrical faults including an open-circuit fault of at least one of the first and second switching elements.

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 magnetic bearing apparatus capable of correcting inclination of a rotating element with a small magnetic attractive force and capable of stably supporting the rotating element is disclosed. The magnetic bearing apparatus includes: a non-magnetic ring made of non-magnetic material; and at least three axial magnetic poles arranged along a circumferential direction of the non-magnetic ring. Each axial magnetic pole has an arc-shaped coil and a coil housing that accommodates the coil therein. The at least three axial magnetic poles are fixed to the non-magnetic ring.

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.

Unique systems, methods, techniques and apparatuses of active magnetic bearing control systems are disclosed. One exemplary embodiment is a power converter electrically coupled to an active magnetic bearing (AMB) having a plurality of windings, the power converter comprising a DC bus, two capacitors, a first leg, a second leg, and a controller. The capacitors are electrically coupled in series between the positive rail and negative rail, one capacitor being electrically coupled to the other capacitor at a midpoint connection. The first leg comprises a first semiconductor switching device and a first output node. The second leg comprises a second semiconductor switching device and a second output node. The first output node is electrically coupled to the midpoint connection by way of a first AMB winding and the second output node is electrically coupled to the midpoint connection by way of a second AMB winding.