Daikin Industries, Ltd.

Atsushi Sakawaki

Keiji Aota

Hiroshi Hibino

Yuji Nakazawa

Yusuke Irino

Naoya Yamashita

Takaaki Ono

Kazuya Hirata

Hirofumi Higashi

Tatsuya Tonari

Taiichi Nose

Shunpei Fujimoto

A drive support unit of a turbo compressor includes at least one bearingless motor. The at least one bearingless motor includes a rotor-stator pair constituted by a rotor and a stator, and is configured to rotationally drive a drive shaft and to support a radial load of the drive shaft in a contactless manner. Accordingly, it is possible to provide a turbo compressor to which a bearingless motor is applied.

Turbo compressor

An electric motor system includes a drive shaft, first and second magnetic bearing portions facing each other and supporting the drive shaft, an electric motor to rotate the drive shaft, and a gap detection unit to detect a position of the drive shaft During rotation of the drive shaft, greater external force acts, on average, on the drive shaft in a first direction than in a second direction. The first and second direction extend from the second and first magnetic bearing portions to the first and second magnetic bearing portion. The first and second magnetic bearing portions produce first and second magnetic forces on the drive shaft in the first and second directions. A magnitude of the second magnetic force is greater than a magnitude of the first magnetic force. The gap detection unit is arranged closer to the second magnetic bearing portion than to the first magnetic bearing portion.

Electric motor system, and turbo compressor provided with same

The stator includes a stator core, a support electric wire formed by one or more conductive wires, and a drive electric wire formed by one or more conductive wires. The stator core includes an annular shaped back yoke and a plurality of teeth on an inner periphery of the back yoke. The support electric wire is disposed so as to pass through a plurality of slots respectively formed between the teeth, and forms a winding portion that generates an electromagnetic force for supporting the rotor in a non-contact manner by being energized. The drive electric wire is disposed so as to pass through the plurality of slots, and forms a winding portion that generates an electromagnetic force for rotating the rotor by being energized. A cross-sectional area per conductive wire of the support electric wire differs from a cross-sectional area per conductive wire of the drive electric wire.

Electric motor and turbo-compressor

Disclosed is a method for calibrating at least one gap sensor, the at least one gap sensor being provided on a magnetic bearing supporting a floating body in a non-contact manner by an electromagnetic force, the at least one gap sensor being configured to detect a gap between the floating body and a reference object that serves as a positional reference for position control of the floating body. The method includes: constructing a transformation formula for transforming an output of the at least one gap sensor into the gap using three or more constraints that are set as conditions for associating the gap with the output of the at least one gap sensor.

Method for calibrating gap sensor

A radial load of a drive shaft is supported by only a plurality of bearingless motors. Maximum values of the radial load acting on the plurality of bearingless motors are not uniform. The bearingless motor, the maximum value of the radial load acting on which is the largest, has a greater maximum value of supporting magnetic flux generated to generate an electromagnetic force for supporting the radial load, compared with the bearingless motor, the maximum value of the radial load acting on which is the smallest. This configuration allows a reduction in size of a rotary system including a load and a drive shaft in an electric motor system.

Electric motor system and turbo compressor provided therewith

A magnetic bearing device includes a magnetic bearing including a plurality of electromagnets, a displacement sensor configured to output an output signal in accordance with a displacement of a shaft, and a controller configured to control the electromagnets. The controller compensates for a change in levels of the output signal, the change occurring in accordance with a change in ambient temperature around the displacement sensor, based on one or more reference values correlating with the change in levels of the output signal. The one or more reference values are detected for use in controlling the rotary electric machine, a fluid machine system including the rotary electric machine, or an apparatus including the fluid machine system.

Magnetic bearing device and fluid machine system using same

A magnetic bearing supports an object to be supported in a noncontact manner by means of a composite electromagnetic force of first and second electromagnets. A processor-based controller causes a first current and a second current to be controlled according to the following equations, where iis the first current flowing to the first electromagnet, iis the second current flowing to the second electromagnet, iis a control current, iis a bias current, gis a reference gap length, x is a displacement amount of the object to be supported with respect to a center position, and a is a predetermined correction coefficient.

Magnetic bearing device and compressor

A controller performs, in a first mode, a first operation for controlling composite electromagnetic force of electromagnets such that a target member moves within a predetermined moving range, and a second operation for acquiring temperature drift correlation information indicative of a correlation between a reference value and an input-output characteristic of a position sensor, based on the reference value and the input-output characteristic of the position sensor in the first operation. The controller performs, in a second mode, a third operation for controlling the composite electromagnetic force of the electromagnets according to a signal level of a detection signal from the position sensor, and a fourth operation for compensating the input-output characteristic of the position sensor in the third operation, based on the temperature drift correlation information and the reference value in the third operation.

Magnetic bearing device and fluid mechanical system

A drive shaft rotates a load. A drive support rotates the drive shaft and supports a radial load of the drive shaft in a non-contact manner, by an electromagnetic force generated by the flow of a current within a predetermined current range through the drive support. A control section controls an operation of the load based on a magnetic flux margin degree expressed by the difference between a total magnetic flux amount generated at the drive support and a predetermined limit of the total magnetic flux amount for the drive support. The total magnetic flux amount includes driving magnetic flux and the supporting magnetic flux in a predetermined operation region of the load. The driving magnetic flux is generated at the drive support for rotating the drive shaft. The supporting magnetic flux is generated at the drive support for supporting a radial load of the drive shaft.

Load operation control system

A magnetic bearing body supports a rotating shaft using a combined electromagnetic force of a pair of control electromagnets without contact. A controller detects a control index value based on a first coil current passed through a coil of a first control electromagnet of the pair of control electromagnets which generates an electromagnetic force in the same direction as that of a load exerted on the rotating shaft, the control index value being an index of the degree of margin for error in control depending on a value of the first coil current. And the controller controls a middle value of a pair of coil currents passed through the respective corresponding coils of the pair of control electromagnets so that the control index value approaches a predetermined target index value.

A stator is provided which exerts a combined electromagnetic force of a plurality of electromagnets on a drive shaft having a fluctuating load. A controller is provided which controls a current difference between a first coil current passed through a coil of the electromagnet generating an electromagnetic force in a direction opposite to that of the load and a second coil current passed through a coil of the electromagnet generating an electromagnetic force in the same direction as that of the load to perform a position control on the drive shaft. The controller adjusts the second coil current to reduce an average value of the second coil current.

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Osaka, Japan

Atsushi Sakawaki