A drive device for an AC motor includes: an adaptive observation unit that adaptively estimates an angular velocity of a rotor of an AC motor; a speed control unit that determines a first torque command with which an angular velocity command matches an average value of an estimated angular velocity; a phase lead amount calculation unit that calculates, based on a disturbance frequency, a phase lead amount of a transfer function from a true angular velocity to a model deviation; a vibration suppression control unit that determines, based on a frequency of load torque pulsations, the model deviation, and the phase lead amount, a second torque command with which speed pulsations in the AC motor are suppressed; and a torque control unit that controls a torque of the AC motor based on the first torque command and the second torque command.

A thrust gas bearing includes a collar portion fixed to a shaft portion, a first base part facing one axial end surface of the collar portion, a first gas film forming part formed between the collar portion and first base part, a second base part facing an other axial end surface of the collar portion, a second gas film forming part formed between the collar portion and second base part, and a cooling flow path to carry a fluid flow. The cooling flow path includes a first flow path formed on one axial end side of the first base part and extending from an axial center toward an outer periphery, and a second flow path formed on an other axial end side of the second base part and extending from an outer periphery toward an axial center. The second to flow path is located downstream of the first flow path.

A thrust gas bearing includes a collar portion fixed to a shaft portion, a first base part facing one axial end surface of the collar portion, a first gas film forming part formed between the collar portion and first base part, a second base part facing an other axial end surface of the collar portion, a second gas film forming part formed between the collar portion and second base part, and a cooling flow path to carry a fluid flow. The cooling flow path includes a first flow path formed on one axial end side of the first base part and extending from an axial center toward an outer periphery, and a second flow path formed on an other axial end side of the second base part and extending from an outer periphery toward an axial center. The second to flow path is located downstream of the first flow path.

A screw compressor includes a screw rotor having a plurality of screw grooves, a plurality of gate rotors each including gates that mesh with the screw rotor, and a casing. The screw rotor is rotatably inserted in the casing. The casing has a cylindrical wall through which the gates pass. The screw compressor has a plurality of compression chambers inside the cylindrical wall. The plurality of compression chambers are defined by the screw rotor and the gates. The compression chambers include a first compression chamber and a second compression chamber. A fluid introduced into the casing at a suction pressure is compressed to an intermediate pressure higher than the suction pressure in the first compression chamber. The fluid at the intermediate pressure is compressed to a discharge pressure higher than the intermediate pressure in the second compression chamber.

A compressor includes: a stator core including a plurality of teeth around which an aluminum winding wire is wound in a concentrated manner; a rotor core disposed on an inner diameter side of the stator core and including a plurality of magnet insertion holes; and a plurality of ferrite magnets inserted in the magnet insertion holes, in which when a width of a winding wire portion formed in each of the teeth is represented as A, a length in an axis direction of the stator core is represented as L, and the number of slots is represented as S, the stator core has a shape that satisfies a relation of 0.3<S×A÷L<2.2.

A compressor and a control method thereof are provided. The compressor includes a motor with a rotor of a permanent magnet. According to embodiments, the method of controlling the compressor includes: applying a detection current to the motor in response to a command of starting the compressor; detecting whether there is demagnetization of the permanent magnet of the rotor according to a response of the motor to the applied detection current; resetting an operating parameter of the compressor if there is the demagnetization; and starting the compressor according to the reset operating parameters. According to embodiments of the present disclosure, when the compressor is to be started, demagnetization is detected first, and the operating parameter are set accordingly, so as to suppress or avoid performance degeneration due to the demagnetization.

A turbo compressor includes a housing with a refrigerant suction hole, through which a refrigerant is introduced, at a front portion thereof, and a motor case defining an accommodation space. The accommodation space includes a rotation shaft extending in a front-rear direction and a motor that is configured to rotate the rotation shaft. A first impeller is coupled to one end of the rotation shaft and a second impeller is coupled to the other end of the rotation shaft. The first impeller is configured to primarily compress the refrigerant introduced into the refrigerant suction hole. A connection passage, that surrounds the motor case extends backward from an outlet of the first impeller. The second impeller is configured to secondarily compress the refrigerant introduced through the connection passage.

A compressor includes a compression mechanism, a motor, a drive shaft, and a motor cooler. The compressor is configured to compress a working fluid. The motor dives the compression mechanism and is housed within a motor housing. The drive shaft is engaged with the motor and the compression mechanism and is configured to drive operation of the compression mechanism. The motor cooler is disposed adjacent the motor and is configured to pump a cooling working fluid around the motor. The motor cooler includes a pump that pumps the cooling working fluid into the motor housing based on a rotational speed of the drive shaft.

A compressor includes a compression mechanism, a motor, a drive shaft, and a motor cooler. The compressor is configured to compress a working fluid. The motor dives the compression mechanism and is housed within a motor housing. The drive shaft is engaged with the motor and the compression mechanism and is configured to drive operation of the compression mechanism. The motor cooler is disposed adjacent the motor and is configured to pump a cooling working fluid around the motor. The motor cooler includes a pump that pumps the cooling working fluid into the motor housing based on a rotational speed of the drive shaft.

A linear compressor or sealed system may include a casing, a piston, an driving coil, an inner back iron assembly, and a planar spring assembly. The casing may include a cylinder assembly defining a chamber along an axial direction. The piston may be slidably received within the chamber of the cylinder assembly. The inner back iron assembly may be positioned in the driving coil. The planar spring assembly may be mounted to the inner back iron assembly. The planar spring assembly may include a first planar spring, a second planar spring axially spaced apart from the first planar spring, and a polymer shim layer disposed between at least a portion of the first planar spring and the second planar spring.