JP2017172742A - Rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a displacement of a rotating shaft even when a positional deviation is caused in a displacement sensor by an ambient temperature change, and provide proper supporting of the rotating shaft in a non-contact state.SOLUTION: A centrifugal compressor 1 of the invention comprises a rotating shaft 5, radial magnetic bearings 7 supporting the rotating shaft 5 in a non-contact state, a displacement sensor 23 detecting displacement in the radial direction of the rotating shaft 5, and a controller 50 controlling a current supplied to the radial magnetic bearings 7 on the basis of a detection result of the displacement sensor 23 such that the displacement of the rotating shaft 5 is eliminated. The controller 50 controls the current while making a correction based on information reflecting a positional deviation of the displacement sensor 23 caused by an ambient temperature change, for instance the temperature detected by a thermocouple 25.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotary machine such as a turbo compressor in which a rotary shaft provided with an impeller is supported by a radial magnetic bearing.

In the centrifugal chiller, the oil system is eliminated and the lubricating oil system is omitted, and the high compression ratio and the intake air volume are increased by increasing the rotation speed of the compressor, the motor is reduced in size and the bearing loss is reduced by increasing the rotation speed of the motor. In order to improve reliability and reduce costs by simplifying the components, adopt a motor direct connection structure of the compressor with the impeller's rotation shaft directly connected to the motor, and support the rotation shaft with a radial magnetic bearing What has been proposed has been proposed (for example, Patent Document 1).
In a rotating machine that supports a rotating shaft with a radial magnetic bearing, the position of the center axis of the rotating shaft is continuously detected by a displacement sensor.For example, when a displacement occurs that causes the center axis to deviate from the center of the bearing due to a disturbance. The amount of current supplied to the magnetic bearing is adjusted so as to increase the magnetic force in the direction to eliminate the displacement. In addition, the magnetic bearing used for a rotary machine is equipped with the electromagnet which opposes the rotating shaft comprised from a magnetic body as a main element at predetermined intervals. This electromagnet is composed of a plurality of poles, for example, a quadrupole electromagnetic coil. When a current is passed through the coil, a magnetic field is generated between the electromagnet and the rotating shaft, and a magnetic attractive force is applied in the radial direction. The rotating shaft is supported in a non-contact manner by magnetically levitating the rotating shaft.

JP 2014-231826 A

  As described above, the magnetic bearing generates a magnetic field so as to cancel the displacement of the rotating shaft as described above. Joule heat is generated in the electromagnetic coil due to its electric resistance as the magnetic field is generated. . Since this generated heat is mainly uneven in the circumferential direction, there is a possibility that the position of the rotating shaft cannot be detected accurately due to the displacement of the displacement sensor due to the thermal expansion of the member supporting the displacement sensor. Thus, when an error occurs in the detection result of the displacement sensor, it becomes difficult to properly support the rotating shaft in a non-contact manner. This displacement sensor error is also related to the temperature drift of the displacement sensor. Incidentally, in an environment where this type of rotating machine is used, a temperature difference of about 70 to 80 ° C. including the heat generation of the coil can occur.

  As described above, the present invention provides a rotating machine capable of accurately detecting the displacement of the rotating shaft and properly supporting the rotating shaft in a non-contact manner even if the displacement sensor is displaced due to a change in ambient temperature. The purpose is to provide.

The rotating machine of the present invention includes a rotating shaft to which an impeller is fixed, a radial magnetic bearing that supports the rotating shaft in a non-contact manner, a displacement sensor that detects a radial displacement of the rotating shaft, and a detection result of the displacement sensor. And a controller for controlling the current supplied to the radial magnetic bearing so that the displacement of the rotating shaft is eliminated.
The controller of the present invention is characterized in that the current is controlled by performing correction based on information reflecting the positional deviation of the displacement sensor accompanying the ambient temperature change.

In the present invention, temperature, strain, and electrical resistance can be used as information reflecting the positional deviation.
That is, the controller according to the present invention can correct the temperature based on the temperature detected as the information reflecting the positional deviation.
Further, the controller according to the present invention can correct based on the distortion detected as information reflecting the positional deviation.
Furthermore, the controller according to the present invention can also perform correction based on the electrical resistance detected as information reflecting the positional deviation.

  The controller according to the present invention holds correction information related to the displacement of the displacement sensor, and performs correction by estimating the amount of displacement of the displacement sensor by collating the information reflecting the displacement with the correction information. Is preferable.

  When the radial magnetic bearing in the present invention includes a plurality of electromagnetic coils that cause the magnetic attraction force to act independently on the rotating shaft, the controller is based on information corresponding to each electromagnetic coil and reflecting the positional deviation. It is preferable to make corrections.

  According to the present invention, the current supplied to the radial magnetic bearing is controlled by correcting based on the information reflecting the displacement of the displacement sensor accompanying the ambient temperature change. Even if the displacement of the displacement sensor occurs, the displacement of the rotating shaft can be accurately detected. Therefore, according to the rotating machine of the present invention, the rotating shaft can be properly supported without contact.

1 is a diagram illustrating an overall configuration of a turbo compressor according to an embodiment of the present invention. It is a figure which shows the arrangement | positioning relationship of the electromagnetic coil in the turbo compressor of FIG. 1, a displacement sensor, and a thermocouple. FIG. 2 is a diagram illustrating a state where a rotation shaft is displaced in the turbo compressor of FIG. 1. (A) shows the example of the correction information based on temperature, (b) is a figure which shows a mode that the distance to a rotating shaft is measured by a displacement sensor. (A) shows the example of the correction information based on distortion, (b) is a figure which shows the example of the correction information based on electrical resistance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A turbo compressor 1 according to the present embodiment is applied to a turbo chiller, a turbo heat pump, and the like (hereinafter collectively referred to as a turbo chiller), and a known refrigeration cycle together with a condenser, a throttle device, and an evaporator. The low-pressure refrigerant gas is compressed into the high-pressure refrigerant gas, thereby having a function of circulating in the refrigeration cycle.
In the turbo compressor 1, the side on which the impellers 3 and 4 are provided is defined as the front, and the opposite side is defined as the rear.

As shown in FIG. 1, the turbo compressor 1 is rotated by an electric motor 2, and a rotary shaft 5 that rotates two stages of impellers 3 and 4 is provided with a pair of front and rear radial magnetic bearings 7, 8 and a pair of thrust magnetic bearings 9 and 10 disposed to face each other.
The electric motor 2 includes a rotor 2A and a stator 2B, and is arranged at a central portion of the motor chamber 6A of the casing 6, and is configured such that a substantially central portion of the rotating shaft 5 is fixedly connected to the rotor 2A. The casing 6 is partitioned into a motor chamber 6A and a compression chamber 6B by a partition wall 6C. A support cylinder 22 extending toward the compression chamber 6B is provided on the partition wall 6C, and a displacement sensor 23 and a thermocouple 25 are provided on the support cylinder 22.
The turbo compressor 1 includes a controller 50 that controls the operation.

As shown in FIG. 2, the radial magnetic bearing 7 includes an iron core 27 extending from the inner peripheral surface of the support cylinder 22 toward the center, and a plurality of electromagnetic coils 28 (28A, 28B, 28C) wound around the iron cores 27. , 28D). 2 is drawn so that the central axis O of the rotating shaft 5 coincides with the center (C) of the radial magnetic bearing 7.
In the radial magnetic bearing 7, when current is supplied to the electromagnetic coils 28 (28A, 28B, 28C, 28D), each of the electromagnetic coils 28A, 28B, 28C, 28D generates a magnetic field independently, and the rotating shaft 5 Magnetic attraction force is applied to Thereby, the radial magnetic bearing 7 supports the rotating shaft 5 in a non-contact manner by magnetically levitating the rotating shaft 5 by this magnetic attraction force. That is, the radial magnetic bearing 7 holds the radial position of the rotary shaft 5 by the radial magnetic force generated by the electromagnetic coil 28. Thus, since the radial magnetic bearing 7 supports the rotating shaft 5 in a non-contact manner, friction between the rotating shaft and the bearing and wear due to friction can be suppressed.
The turbo compressor 1 of the present embodiment is intended to properly support the rotating shaft 5 in a non-contact manner by the radial magnetic bearing 7 even if the temperature changes.

The current supplied to the electromagnetic coils 28A, 28B, 28C, 28D is controlled by the controller 50 described later.
Since the electromagnetic coil 28 applies a magnetic attraction force to the rotating shaft 5, for example, in FIG. 2, if the current value supplied to the electromagnetic coil 28B is made larger than that of the other electromagnetic coils 28A, 28C, 28D, the rotating shaft 5 can be displaced so as to be closer to the electromagnetic coil 28B than before. Similarly, in FIG. 2, if the current value supplied to the electromagnetic coils 28B and 28C is made larger than that of the other electromagnetic coils 28A and 28D, the rotary shaft 5 can be displaced downward in the figure than before. Thus, by controlling the current value supplied to each of the electromagnetic coils 28A, 28B, 28C, and 28D of the radial magnetic bearing 7, the center axis O of the rotating shaft 5 coincides with the center (C) of the radial magnetic bearing 7. Control to do. Note that the displacement of the central axis O of the rotary shaft 5 from the center of the radial magnetic bearing 7 is referred to as the displacement of the rotary shaft 5.
Although the radial magnetic bearing 7 has been described here, the radial magnetic bearing 8 has the same configuration as that of the radial magnetic bearing 7 and can perform the same control.
In the turbo compressor 1 that supports the rotary shaft 5 by the radial magnetic bearings 7 and 8, the radial magnetic bearings 7 and 8 serve as auxiliary bearings for supporting the rotary shaft 5 when the radial magnetic bearings 7 and 8 fail or stop. It is being installed near 8. As this auxiliary bearing, a rolling bearing is usually used.

  As shown in FIG. 1, a thrust disk 11 is fixedly installed at the rear end of the rotating shaft 5, and a pair of thrust magnetic bearings 9 and 10 are arranged opposite to each other with a predetermined gap between the thrust disk 11. Has been. The pair of thrust magnetic bearings 9 and 10 generate a magnetic attraction force by an electric current supplied to the electromagnetic coil, and support the thrust load applied to the rotary shaft 5 by disposing the thrust disk 11 therebetween. Therefore, by adjusting the distribution of the current supplied to each electromagnetic coil and controlling the magnetic attractive force of each bearing 9, 10 with respect to the thrust disk 11, the support position in the direction of the central axis O of the rotating shaft 5 can be arbitrarily set. Control to position.

  As shown in FIG. 1, the compression chamber 6 </ b> B of the casing 6 includes a low-stage compression unit 12 in which the first-stage impeller 3 is disposed, and a high-stage compression unit 13 in which the second-stage impeller 4 is disposed. The low-pressure refrigerant gas sucked from the suction port 14 through the inlet vane 15 is compressed by the low-stage side compression unit 12 and the discharge gas is sucked by the high-stage side compression unit 13 to generate a high pressure. The refrigerant gas is compressed in two stages. Each impeller 3 and 4 is fixed to the front end side of the rotating shaft 5 and is driven to rotate by the electric motor 2.

  The first stage impeller 3 and the second stage impeller 4 are so-called open type impellers in which the shrouds 16 and 17 are separated from the respective impellers 3 and 4 and provided on the casing 6 side. A small seal gap is formed between the shrouds 16 and 17 and the impellers 3 and 4. Similarly, a minute seal gap is also formed between the rear surface of the hub side of the first stage impeller 3 and the second stage impeller 4 or the outer periphery of the rotary shaft 5 and the partition wall 6 </ b> C provided in the casing 6.

  As shown in FIGS. 1 and 2, a displacement sensor 23 for measuring the displacement of the rotating shaft 5 is provided between the radial magnetic bearing 7 and the compression chamber 6B inside the motor chamber 6A and around the rotating shaft 5. Is provided. Specifically, the displacement sensor 23 is supported by the support cylinder 22. In this embodiment, as shown in FIG. 2, four displacement sensors 23 are arranged at intervals of 90 °. The four displacement sensors 23 are referred to as the displacement sensors 23A, 23B, 23C, and 23D, respectively. In the present embodiment, the type of the displacement sensor 23 is arbitrary, and a known displacement sensor such as an optical type (laser), an eddy current type, or an ultrasonic type can be applied.

As shown in FIG. 2, the displacement sensors 23A, 23B, 23C, and 23D are disposed at positions that are 45 degrees out of phase with the electromagnetic coils 28A, 28B, 28C, and 28D in the circumferential direction.
The displacement sensors 23A, 23B, 23C, and 23D are set to have the same distance to the center (C) of the radial magnetic bearing 7 (the central axis O of the rotary shaft 5 in FIG. 2). While driving, the distance to the surface of the rotating shaft 5 is continuously measured. The distance information L1, L2, L3, L4 detected by each of the displacement sensors 23A, 23B, 23C, 23D is sent to the controller 50.

  For example, as illustrated in FIG. 3A, it is assumed that the rotary shaft 5 is displaced during the operation of the turbo compressor 1. In this example, the rotation shaft 5 is displaced toward the displacement sensor 23D and the center axis O is deviated from the center C of the radial magnetic bearing 7. However, the distance information L1 is obtained for each of the displacement sensors 23A, 23B, 23C, and 23D. , L2, L3, and L4 are detected. FIG. 3B differs from FIG. 3A in the direction of displacement of the rotating shaft 5, but distance information L1, L2, L3, and L4 are similarly detected.

In the turbo compressor 1, as shown in FIGS. 1 and 2, a thermocouple 25 as a temperature sensor is supported by a support cylinder 22 on which a displacement sensor 23 is supported.
In the present embodiment, the thermocouple 25 has four thermocouples 25 arranged at intervals of 90 °. When the four thermocouples 25 are distinguished from each other, they are referred to as thermocouples 25A, 25B, 25C, and 25D. When collectively referred to without distinction, they are referred to as thermocouples 25. Each of the thermocouples 25A, 25B, 25C, 25D is arranged at the same phase position as the displacement sensors 23A, 23B, 23C, 23D in the circumferential direction.
As described above, the thermocouple 25 (25A, 25B, 25C, 25D) detects the temperature of the support cylinder 22 on which the displacement sensor 23 (23A, 23B, 23C, 23D) is supported. More specifically, each of the thermocouples 25A, 25B, 25C, and 25D detects the temperature at the position as information that reflects the displacement of the displacement sensors 23A, 23B, 23C, and 23D. Information about the temperature of the support cylinder 22 detected by each of the thermocouples 25A, 25B, 25C, and 25D is sent to the controller 50 as temperature information T1, T2, T3, and T4.

The turbo compressor 1 includes a controller 50 that distributes and controls the current supplied to the radial magnetic bearing 7. The controller 50 controls the current supplied to the radial magnetic bearing 7 based on the detection result of the displacement sensor 23 so that the displacement of the rotating shaft 5 is eliminated.
In order to execute this control, the controller 50 acquires distance information L1, L2, L3, L4 measured by each of the displacement sensors 23A, 23B, 23C, 23D, and acquires the acquired distance information L1, L2, L3. Based on L4, the current value to be supplied to the electromagnetic coils 28A, 28B, 28C, 28D constituting the radial magnetic bearing 7 is set and the current is supplied. The electromagnetic coils 28 </ b> A, 28 </ b> B, 28 </ b> C, 28 </ b> D receive the current supplied from the controller 50, thereby causing the magnetic attraction force to act on the rotary shaft 5 based on the respective current values, so that the rotary shaft 5 is at a desired position. Support for rotation.
The controller 50 can also perform control other than controlling the current supplied to the electromagnetic coil 28.

  The controller 50 also takes into account the temperature information T1, T2, T3, T4 sent from the thermocouples 25A, 25B, 25C, 25D to set the current value supplied to the electromagnetic coils 28A, 28B, 28C, 28D. . That is, Joule heat is generated in the electromagnetic coil 28 due to the electrical resistance of the coil, and this heat is mainly uneven in the circumferential direction. Therefore, the heat is applied due to the displacement of the displacement sensor 23 due to the thermal expansion of the support cylinder 22. As a result, the temperature drift of the displacement sensor 23 may prevent the displacement sensor 23 from accurately detecting the position of the rotating shaft 5. Therefore, the controller 50 corrects the error of the displacement sensor 23 by referring to the temperature information T1, T2, T3, T4 as information reflecting the displacement of the displacement sensor 23.

In order to correct the error of the displacement sensor 23, the controller 50 includes correction information as shown in FIG. As shown in FIG. 4A, the correction information is preset for each of the displacement sensors 23A, 23B, 23C, and 23D, and the temperature T and the displacement sensors 23A, 23B, and 23C at the temperature T are set. , 23D shift amount x (x1, x2, x3, x4). In other words, the correction information is information representing the displacement amount x (x1, x2, x3, x4) of the displacement sensors 23A, 23B, 23C, 23D as a function of the temperature T.
Here, the shift amount x means a displacement generated in the displacement sensor 23 due to heat generation of the electromagnetic coil 28, and this displacement differs depending on each displacement sensor 23A, 23B, 23C, 23D even at the same temperature T. Therefore, the shift amount x generated in each of the displacement sensors 23A, 23B, 23C, and 23D is referred to as shift amounts x1, x2, x3, and x4.

  The correction information includes the displacement information x1, x2, x3, x4 of the displacement sensors 23A, 23B, 23C, 23D and the temperature information T1, T2 of the thermocouples 25A, 25B, 25C, 25D while the turbo compressor 1 is actually operated. , T3, T4 can be detected to obtain test data. Further, the correction information is not limited to test data, and can be obtained by analysis by simulation.

Here, the shift amount x will be described with reference to FIG.
4B, the right side (b-1) shows an ideal state where the rotation shaft 5 is not displaced and the displacement sensor 23 is not displaced. The distance to the surface is L. The middle (b-2) shows a state in which the rotational shaft 5 is displaced (y) in the radial direction but no displacement occurs in the displacement sensor 23. The distance from the displacement sensor 23 to the surface of the rotational shaft 5 is shown. Is L + y. When the radial displacement x occurs in the displacement sensor 23, the distance from the displacement sensor 23 to the surface of the rotating shaft 5 is L + y−x. What is actually detected by the displacement sensor 23 is the distance L + y−x.
As described above, in order to make the central axis O of the rotating shaft 5 coincide with the center C of the radial magnetic bearing 7, the current supplied to the radial magnetic bearing 7 after correcting the positional deviation x of the displacement sensor 23 is corrected. To control.

  The controller 50 sets the current value to be supplied to the electromagnetic coils 28A, 28B, 28C, 28D based on the distance information L1, L2, L3, L4 and the temperature information T1, T2, T3, T4. This setting corresponds to each of the thermocouples 25A, 25B, 25C, and 25D. The procedure 2 calculates the command current value I (I1, I2, I3, I4) supplied to the electromagnetic coils 28A, 28B, 28C, 28D corresponding to the distances ΔL1, ΔL2, ΔL3, ΔL4.

The procedure 1 is executed by a function expression including the following expressions (1) to (4). These expressions (1) to (4) are stored in the storage means constituting the controller 50. When the controller 50 acquires the distance information L1, L2, L3, and L4 and the temperature information T1, T2, T3, and T4, the distance information L and the temperature information T1 to T4 acquired are substituted into the expressions (1) to (4). Then, the movement distances ΔL1, ΔL2, ΔL3, ΔL4 are obtained.
ΔL1 = L1 + f1 (T1) (1)
ΔL2 = L2 + f2 (T2) (2)
ΔL3 = L3 + f3 (T3) Expression (3)
ΔL4 = L4 + f4 (T4) Equation (4)

  Here, in the functional expressions (1) to (4), the portions of f1 (T1), f2 (T2), f3 (T3), and f4 (T4) are the temperature information in the correction information shown in FIG. The content is to estimate the displacement amount of the displacement sensor 23 by collating the information T1, T2, T3, and T4.

If the movement distances ΔL1, ΔL2, ΔL3, and ΔL4 are obtained by the procedure 1, the controller 50 is executed as a procedure 2 by a function formula including the following formulas (5) to (8). When the controller 50 obtains the indicated current values I1, I2, I3, and I4, it supplies the current to each of the electromagnetic coils 28A, 28B, 28C, and 28D.
I1 = F1 (y1) (5)
I2 = F2 (y2) (6)
I3 = F3 (y3) (7)
I4 = F4 (y4) (8)

[Operation]
The turbo compressor 1 having the above configuration operates as follows.
When the turbo compressor 1 is operated, the first stage impeller 3 and the second stage impeller 4 are rotated by the electric motor 2 via the rotation shaft 5. As a result, the low-pressure refrigerant gas is sucked into the low-stage compression section 12 from the suction port 14 via the inlet vane 15 and compressed, and the discharge gas is sucked in by the high-stage compression section 13 to generate a high-pressure refrigerant gas. Are compressed in two stages and discharged from the turbo compressor 1 to the outside.

  While the turbo compressor 1 continues the operation of compressing the low-pressure refrigerant gas to the high-pressure refrigerant gas as described above, the controller 50 receives the distance information L1, L2, L3 from the displacement sensors 23A, 23B, 23C, 23D. , L4 and temperature information T1, T2, T3, T4 from the thermocouples 25A, 25B, 25C, 25D. Then, the controller 50 obtains the instruction current values I1, I2, I3, and I4 by the procedure 1 and procedure 2 described above, and supplies the current to the electromagnetic coils 28A, 28B, 28C, and 28D.

[Effect]
According to this embodiment, the controller 50 acquires temperature information T1, T2, T3, and T4 in addition to the distance information L1, L2, L3, and L4, and corrects the error due to the displacement of the displacement sensor 23 due to thermal expansion. The command current values I1, I2, I3, and I4 are supplied to the electromagnetic coils 28A, 28B, 28C, and 28D, respectively. Therefore, even if the temperature rise and temperature drop around the radial magnetic bearing 7 occur, the position of the rotary shaft 5 with respect to the center C of the radial magnetic bearing 7 can be detected accurately, so that the rotary shaft 5 is supported by the radial magnetic bearing 7. Can be performed stably.

In the present embodiment, four thermocouples 25A, 25B, 25C, and 25D are provided corresponding to the displacement sensors 23A, 23B, 23C, and 23D of the rotary shaft 5, and the controller 50 uses the thermocouples 25A, 25B, 25C, and 25D. The command current values I1, I2, I3, and I4 are set on the basis of the detection result. Therefore, the position of the rotating shaft 5 can be detected with high accuracy for each of the displacement sensors 23A, 23B, 23C, and 23D.
Although the thermocouple 25 is used to detect the temperature, other temperature sensors can also be used. For example, as described later, the present invention can detect the temperature based on the electric resistance R of the electromagnetic coil 28, but a temperature detecting coil is provided separately from the electromagnetic coil 28 to detect the electric resistance R. You can also.

The preferred embodiments of the present invention have been described above. However, the configurations described in the above embodiments can be selected or changed to other configurations as appropriate without departing from the gist of the present invention.
For example, in the above embodiment, the temperature is detected using the thermocouple 25 in order to obtain the command current values I1, I2, I3, and I4. However, the present invention can use any information that reflects the displacement of the displacement sensor 23 accompanying a change in ambient temperature. That is, the temperature of the support cylinder 22 is detected by the thermocouple 25 in order to detect the displacement of the displacement sensors 23A, 23B, 23C, and 23D due to the thermal expansion of the support cylinder 22, so that the thermocouple 25 is used instead. A strain gauge can be provided on the support tube 22. In this case, the controller 50 is provided with correction information as in the above-described embodiment. This correction information is provided for each of the displacement sensors 23A, 23B, 23C, and 23D as shown in FIG. The information is set in advance, and is information in which the strain λ is associated with the displacement amount x (x1, x2, x3, x4) of the displacement sensors 23A, 23B, 23C, and 23D at the strain λ. Using the correction information, the command current values I1, I2, I3, and I4 can be obtained in the same manner as in the procedure 1 and procedure 2 described above.
Since this method uses the strain λ that directly reflects the thermal expansion of the support cylinder 22, the displacement of the displacement sensor 23 can be accurately detected.

As another means, the electric resistance R of the electromagnetic coils 28A, 28B, 28C, 28D can be detected. The electric resistance R of the electromagnetic coil 28 utilizes a property that changes depending on the temperature of the electromagnetic coil 28. As shown in FIG. 5B, the correction information is preset for each of the displacement sensors 23A, 23B, 23C, and 23D, and includes an electric resistance R and a displacement sensor 23A in the electric resistance R. 23B, 23C, and 23D deviation amounts x (x1, x2, x3, x4) are associated with each other. Using the correction information, the command current values I1, I2, I3, and I4 can be obtained in the same manner as in the procedure 1 and procedure 2 described above.
Since this method uses the original electromagnetic coil 28, it is possible to suppress an increase in cost of providing a new member.

  Moreover, although the above embodiment demonstrated the turbo compressor 1 as a specific example of a rotary machine, this invention is applicable also to the rotary machine which uses a radial magnetic bearing, for example, a centrifugal compressor.

In the above embodiment, the time intervals for detecting the distance information L1, L2, L3, L4 and the temperature information T1, T2, T3, T4 are arbitrary, and can be detected at intervals of several seconds, for example. It can be detected at intervals of several minutes.
Furthermore, the numbers and arrangements of the electromagnetic coils 28, the displacement sensors 23, and the thermocouples 25 in the above embodiment are merely examples, and other numbers and arrangements may be adopted.
Furthermore, in the present embodiment, the thermocouple 25 is provided in the support cylinder 22, but this is only an example, and the position for detecting the information reflecting the displacement of the displacement sensor 23 is not limited to the temperature. It is. However, in order to detect temperature and strain, it is preferable to target a member that directly supports the displacement sensor 23 as in this embodiment.

DESCRIPTION OF SYMBOLS 1 Turbo compressor 2 Electric motor 2A Rotor 2B Stator 3 First stage impeller 4 Second stage impeller 5 Rotating shaft 6 Casing 6A Motor chamber 6B Compression chamber 6C Partition walls 7, 8 Radial magnetic bearing 9, 10 Thrust magnetic bearing 11 Thrust Disc 12 Lower stage compression section 13 High stage compression section 14 Suction port 15 Inlet vanes 16, 17 Shroud 22 Support cylinders 23, 23A, 23B, 23C, 23D Displacement sensors 25, 25A, 25B, 25C, 25D Thermocouple 27 Iron core 28, 28A, 28B, 28C, 28D Electromagnetic coil 50 Controller C Center O Center axis

Claims (6)

A rotating shaft to which the impeller is fixed;
A radial magnetic bearing for supporting the rotating shaft in a non-contact manner;
A displacement sensor for detecting a radial displacement of the rotating shaft;
A controller for controlling a current supplied to the radial magnetic bearing so as to eliminate the displacement of the rotating shaft based on a detection result of the displacement sensor,
The controller is
Correcting the displacement based on the information reflecting the displacement of the displacement sensor accompanying the ambient temperature change, and controlling the current,
A rotating machine characterized by that. The controller is
Performing the correction based on the temperature detected as information reflecting the positional deviation;
The rotating machine according to claim 1. The controller is
The correction is performed based on the strain detected as information reflecting the positional deviation.
The rotating machine according to claim 1. The controller is
Performing the correction based on the electrical resistance detected as information reflecting the positional deviation;
The rotating machine according to claim 1. The controller is
Holding correction information related to the displacement of the displacement sensor,
The amount of positional deviation of the displacement sensor is estimated by comparing the information reflecting the positional deviation with the correction information, and the correction is performed.
The rotary machine as described in any one of Claims 1-4. The radial magnetic bearing is
A plurality of electromagnetic coils for independently acting magnetic attraction force on the rotating shaft;
The controller is
The correction is performed based on information corresponding to each electromagnetic coil and reflecting the positional deviation.
The rotary machine as described in any one of Claims 1-5.

Images