JP2016178801A - Switched reluctance rotary machine and rotary device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switched reluctance rotary machine which secures an installation space of a magnetic bearing and achieves downsizing of the entire machine, and to provide a rotary device.SOLUTION: A switched reluctance motor 1 has: a rotor 10 having an annular rotor yoke 11 and a rotor salient pole 12 protruding from an outer peripheral surface 11a of the rotor yoke 11; and an outer stator 20 having a stator coil 23 facing the rotor salient pole 12. The rotor yoke 11 has a space part 13 at the radial inner side and includes a magnetic bearing 30 disposed in the space part 13.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a switched reluctance rotating machine and a rotating device.

  The switched reluctance rotating machine has a configuration in which a rotor does not have permanent magnets or windings and operates by a magnetic attractive force generated between the rotor and the stator. Switched reluctance rotating machines have problems such as vibration and noise in principle, but the structure is simple and robust, can withstand high-speed rotation, and expensive permanent magnets such as neodymium magnets are unnecessary. In recent years, research and development for practical application of a rotating machine with low cost and excellent reliability has been promoted. As such a switched reluctance rotating machine, for example, a reluctance motor described in Patent Document 1 below is known.

JP-A-5-336715

  By the way, when the reluctance type electric motor as in the above prior art is applied to a rotating device such as a centrifugal compressor, the rotor is connected to a shaft for rotating the impeller. In a centrifugal compressor, in order to rotate a shaft at high speed, a magnetic bearing may be adopted as a bearing that supports the shaft. Since the magnetic bearing supports the shaft in a non-contact manner, friction with the shaft does not occur and the life is long. However, the magnetic bearing has to support the shaft with a predetermined axial length, and there is a problem that the entire apparatus becomes large in order to secure an installation space.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a switched reluctance rotating machine and a rotating device that can secure an installation space for a magnetic bearing and can reduce the size of the entire device.

In order to solve the above-mentioned problems, the present invention includes an annular rotor yoke, a rotor having a rotor salient pole protruding from the outer peripheral surface of the rotor yoke, and an outer stator having a stator coil facing the rotor salient pole. In the switched reluctance rotating machine, a configuration is adopted in which the rotor yoke has a space portion radially inside and has a magnetic bearing disposed in the space portion.
By adopting this configuration, in the present invention, a space is provided inside the rotor yoke of the rotor in the radial direction, and a magnetic bearing is disposed in this space. Thereby, a magnetic bearing can be incorporated inside the rotor in the radial direction without changing the basic structure between the outer stator and the rotor. Therefore, it is not necessary to secure an installation space for the magnetic bearing outside the rotating machine body, and the entire apparatus can be reduced in size.

In the present invention, the magnetic bearing includes an annular yoke portion, a core that protrudes from the outer peripheral surface of the yoke portion and has a protrusion that faces the inner peripheral surface of the rotor yoke with a gap therebetween, and the protrusion And a coil wound around.
By adopting this configuration, in the present invention, the rotor can be magnetically supported from the radially inner side by winding a coil around the core protrusion facing the inner circumferential surface of the rotor yoke with a gap. . The core is a heteropolar type that has an annular yoke portion, and the protrusion can be formed integrally with the yoke portion. For this reason, manufacture becomes easy compared with the homopolar type | mold with which the core became independent one by one.

In the present invention, a configuration is adopted in which the rotor yoke has a thickness corresponding to the magnetic characteristics of the outer stator and the magnetic bearing.
By adopting this configuration, in the present invention, by sufficiently securing the thickness of the rotor yoke according to the magnetic characteristics of the outer stator and the magnetic bearing, the magnetic flux flowing from the outer stator to the rotor yoke and the magnetic bearing to the rotor yoke It is possible to prevent interference with the magnetic flux flowing into the.

Further, the present invention employs a rotating device that includes the switched reluctance rotating machine described above, a shaft that rotates via the switched reluctance rotating machine, and a load device provided on the shaft. .
By adopting this configuration, in the present invention, it is possible to obtain a rotating device that can secure an installation space for the magnetic bearing and can downsize the entire device.

In the present invention, the switched reluctance rotating machine includes: a first magnetic bearing disposed on one side of the space portion in the axial direction of the shaft; and the other side of the space portion in the axial direction of the shaft. And a second magnetic bearing disposed on the surface.
By adopting this configuration, in the present invention, the first magnetic bearing and the second magnetic bearing are incorporated into the switched reluctance rotating machine, and the first magnetic bearing and the second magnetic bearing are arranged on one side and the other side of the space in the axial direction of the shaft. By controlling the displacement in the first magnetic bearing and the second magnetic bearing, the parallelism of the shaft can be adjusted. Since only one switched reluctance rotating machine is required, the entire apparatus can be further downsized.

  ADVANTAGE OF THE INVENTION According to this invention, the installation space of a magnetic bearing is ensured and the switched reluctance rotary machine and rotary apparatus which can reduce the whole apparatus are obtained.

It is a whole block diagram of the centrifugal compressor in 1st Embodiment of this invention. It is sectional drawing of the switched reluctance motor in 1st Embodiment of this invention. It is a graph which shows the performance evaluation of the magnetic bearing provided in the switched reluctance motor in 1st Embodiment of this invention. It is a figure which shows magnetic flux density distribution of the switched reluctance motor in A point and B point shown in FIG. It is a figure which shows magnetic flux density distribution of the switched reluctance motor in C point shown in FIG. 3, and D point. It is a figure which shows magnetic flux density distribution of the switched reluctance motor in the E point shown in FIG. 3, and F point. It is a graph which shows the relationship between the output of the switched reluctance motor in 1st Embodiment of this invention, and the support force of a magnetic bearing. It is a whole block diagram of the centrifugal compressor in 2nd Embodiment of this invention.

  Hereinafter, a switched reluctance rotating machine and a rotating device of the present invention will be described with reference to the drawings. In the following description, a switched reluctance motor is exemplified as the switched reluctance rotating machine. In the following description, a centrifugal compressor is exemplified as the rotating device.

(First embodiment)
FIG. 1 is an overall configuration diagram of a centrifugal compressor 100 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the switched reluctance motor 1 according to the first embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG.
As shown in FIG. 1, the centrifugal compressor 100 includes a switched reluctance motor 1, a shaft 101, an impeller 102 (load device), an axial magnetic bearing 103, and a radial magnetic bearing 104.

The switched reluctance motor 1 includes a motor main body 2 shown in FIG. 2, a motor drive device 3 shown in FIG. 1 that drives the motor main body 2, a magnetic bearing controller 4, and a displacement sensor 5.
As shown in FIG. 2, the motor body 2 includes a rotor 10, an outer stator 20, and a magnetic bearing 30. The switched reluctance motor 1 of this embodiment is a U-phase, V-phase, and W-phase three-phase motor. The number of poles on the stator side is twelve, and the number of poles on the rotor side is eight. It has a structure.

  The rotor 10 is a magnetic body in which, for example, a plurality of electromagnetic steel plates are laminated in the axial direction of the shaft 101 (the direction perpendicular to the paper surface in FIG. 2). The rotor 10 includes a rotor yoke 11 and a rotor salient pole 12. The rotor yoke 11 is annular. A rotor salient pole 12 is provided on the outer peripheral surface 11 a of the rotor yoke 11. A plurality of rotor salient poles 12 are provided on the outer peripheral surface 11a. Eight rotor salient poles 12 of this embodiment are provided on the outer peripheral surface 11a at 45 ° intervals.

  On the other hand, the rotor salient pole 12 is not provided on the inner peripheral surface 11 b of the rotor yoke 11. That is, the cross-sectional contour orthogonal to the axial direction of the inner peripheral surface 11b is a circle. Further, the center of the inner peripheral surface 11 b coincides with the rotation center of the rotor 10. The rotor yoke 11 has a space portion 13 on the radially inner side. The space 13 is surrounded by the inner peripheral surface 11b. The space 13 is a cylindrical space extending in the axial direction.

  The outer stator 20 is disposed outside the rotor 10. The outer stator 20 includes a stator yoke 21, a stator salient pole 22, and a stator coil 23. The stator yoke 21 is made of a magnetic material. The stator yoke 21 is annular. The stator salient pole 22 is provided integrally with the stator yoke 21. The stator salient poles 22 project radially inward from the stator yoke 21.

  Twelve stator salient poles 22 are provided on the inner circumference of the stator yoke 21 at 30 ° intervals. The stator coil 23 is wound around each of the stator salient poles 22 using a slot opening formed between the stator salient poles 22 adjacent in the circumferential direction. The stator coils 23 are arranged in the order of U phase → V phase → W phase → U phase →... Along the circumferential direction. A three-phase alternating current is supplied from the motor driving device 3 to the stator coil 23 as a driving current.

  The motor drive device 3 includes, for example, a DC power supply, an inverter that converts a DC current into an AC current and supplies the stator coil 23 of the outer stator 20, a booster circuit provided between the DC power supply and the inverter, And a smoothing capacitor for smoothing the output voltage of the circuit. When electric power is supplied to the stator coil 23 of the outer stator 20, a magnetic field is formed by the stator coil 23, and torque is applied to the rotor 10 by the magnetic field acting on the rotor salient poles 12.

  The magnetic bearing 30 supports the rotor 10 in a non-contact manner. As shown in FIG. 2, the magnetic bearing 30 is disposed in the space 13 on the radially inner side of the rotor yoke 11. The magnetic bearing 30 is supported by the housing of the motor body 2. The magnetic bearing 30 of this embodiment is a heteropolar radial magnetic bearing. The magnetic bearing 30 has a core 31 and a coil 32. The core 31 is, for example, a magnetic body in which a plurality of electromagnetic steel plates are laminated in the axial direction. The core 31 has a yoke portion 33 and a protrusion 34.

  The yoke part 33 is annular. A protrusion 34 is provided on the outer peripheral surface 33 a of the yoke portion 33. A plurality of protrusions 34 are provided on the outer peripheral surface 33a. In the present embodiment, eight protrusions 34 are provided on the outer peripheral surface 33a at 45 ° intervals. The protrusion 34 is opposed to the inner peripheral surface 11 b of the rotor yoke 11 with a gap.

  The coil 32 is wound around the protrusion 34. The coil 32 includes a first coil 32a, a second coil 32b, a third coil 32c, and a fourth coil 32d that are wound as a pair of protrusions 34 that are adjacent in the circumferential direction. The first coil 32 a to the fourth coil 32 d form a closed magnetic path 40 that passes through the core 31 and the rotor yoke 11.

  The first coil 32 a and the third coil 32 c are arranged in pairs in the horizontal direction (X-axis direction) passing through the center of the rotor 10. Further, the second coil 32 b and the fourth coil 32 d are arranged in pairs in the vertical direction passing through the center of the rotor 10. Power is supplied to the first coil 32a to the fourth coil 32d in a direction in which the closed magnetic paths 40 do not interfere with each other magnetically, and the polarity of the coil 32 (projection 34) is N pole → N pole → S poles → S poles → N poles are arranged alternately in this order.

  A displacement sensor 5 shown in FIG. 1 is a radial displacement sensor that measures the radial displacement of the rotor 10. The displacement sensor 5 detects the position of the sensor target 6 provided in the rotor 10 to measure at least two-axis displacements of the X axis and the Y axis (see FIG. 2).

  The magnetic bearing controller 4 performs feedback control for adjusting the bias current (DC current) supplied to the magnetic bearing 30 based on the measurement result of the displacement sensor 5. Specifically, the magnetic bearing controller 4 increases or decreases the bias current supplied to the first coil 32 a to the fourth coil 32 d based on the measurement result of the displacement sensor 5. For example, when the shaft 101 is moved in the X-axis direction, the bias current supplied to the first coil 32a and the third coil 32c is increased or decreased.

  Returning to FIG. 1, the centrifugal compressor 100 includes the switched reluctance motor 1 having the above-described configuration. The switched reluctance motor 1 supports one end of the shaft 101 in the axial direction (the end on the right side in FIG. 1). The shaft 101 rotates via the switched reluctance motor 1.

  The shaft 101 is supported via the rotor 10 that is supported in a non-contact manner by the magnetic attractive force of the magnetic bearing 30. The shaft 101 is provided with a touch-down bearing (auxiliary bearing) (not shown). At the start of operation of the switched reluctance motor 1, after operation, or when the shaft 101 receives a sudden load. The rotor 10 does not contact the magnetic bearing 30 and the shaft 101 does not contact the radial magnetic bearing 104 or the like.

  The impeller 102 is provided at the other end portion of the shaft 101 in the axial direction (the end portion on the left side in FIG. 1). The impeller 102 is a radial impeller that applies a centrifugal force to the gas taken in from the axial direction by being rotationally driven through the shaft 101. The impeller 102 is surrounded by an impeller housing (not shown), and the impeller housing is configured to pressurize a gas to which centrifugal force is applied in a diffuser flow path disposed on the radially outer side of the impeller 102. Yes.

  The axial magnetic bearing 103 is provided between the switched reluctance motor 1 and the radial magnetic bearing 104. The axial bearing 103 is a normal type axial magnetic bearing that receives a load in the axial direction of the shaft 101 in a non-contact manner. The axial bearing 103 may be a contact type axial bearing. The axial magnetic bearing 103 includes a displacement sensor 103a that measures the axial displacement of the shaft 101, and an axial magnetic bearing that performs feedback control for adjusting a bias current supplied to the axial magnetic bearing 103 based on the measurement result of the displacement sensor 103a. And a controller 103b.

  The radial magnetic bearing 104 is provided between the impeller 102 and the axial magnetic bearing 103. The radial magnetic bearing 103 is a normal radial magnetic bearing that receives a load in the radial direction of the shaft 101 in a non-contact manner. The radial magnetic bearing 104 may be a contact type radial bearing. The radial magnetic bearing 104 includes a displacement sensor 104a that measures the radial displacement of the shaft 101, and a radial magnetic bearing that performs feedback control for adjusting a bias current supplied to the radial magnetic bearing 104 based on the measurement result of the displacement sensor 104a. And a controller 104b.

  According to the centrifugal compressor 100 having the above-described configuration, the normal type radial magnetic bearing 104 and the switched reluctance motor 1 in which the magnetic bearing 30 is incorporated are arranged at intervals in the axial direction of the shaft 101, so that the radial magnetic Displacement control can be performed by each of the bearing 104 and the magnetic bearing 30. Thus, the parallelism of the shaft 101 can be easily adjusted by performing displacement control at two locations spaced apart in the axial direction with respect to the shaft 101.

  Further, according to the switched reluctance motor 1 having the above configuration, as shown in FIG. 2, the magnetic bearing 30 is arranged in the space portion 13 provided on the radially inner side of the rotor yoke 11. Thereby, the magnetic bearing 30 can be incorporated inside the rotor 10 in the radial direction without changing the basic structure between the outer stator 20 and the rotor 10. Therefore, as shown in FIG. 1, it is not necessary to secure an installation space for the magnetic bearing 30 outside the motor body 2, and the entire apparatus can be downsized. That is, the motor main body 2 and the magnetic bearing 30 are integrated as one piece of hardware and become compact, and the shaft length of the entire shaft 101 can be shortened.

  Further, as shown in FIG. 2, the magnetic bearing 30 of the present embodiment protrudes from the annular yoke portion 33 and the outer peripheral surface 33 a of the yoke portion 33 so as to face the inner peripheral surface 11 b of the rotor yoke 11 with a gap therebetween. It has a core 31 having a portion 34 and a coil 32 wound around the protrusion 34. According to this configuration, the rotor 10 can be magnetically supported from the radially inner side by winding the coil 32 around the protrusion 34 of the core 31 that is opposed to the inner peripheral surface 11b of the rotor yoke 11 with a gap. . The core 31 has a ring-shaped yoke portion 33 and is a heteropolar type in which the protrusion 34 can be formed integrally with the yoke portion 33. For this reason, manufacture becomes easy compared with the homopolar type | mold with which the core became independent one by one.

FIG. 3 is a graph showing the performance evaluation of the magnetic bearing 30 provided in the switched reluctance motor 1 according to the first embodiment of the present invention. As shown in FIG. 3, the vertical axis represents the supporting force [kN], and the horizontal axis represents the magnetomotive force [A].
FIG. 3 is a static magnetic field analysis result showing a change in the supporting force of the magnetic bearing 30 when the magnetomotive force is increased. As shown in FIG. 3, it can be seen that the greater the magnetomotive force, the greater the support force of the magnetic bearing 30. For this reason, it can be seen that the rotor 10 can be sufficiently supported in a non-contact manner by adjusting the magnetomotive force according to the weight of the rotor 10.

  In the present embodiment, the rotor yoke 11 has a thickness corresponding to the magnetic characteristics of the outer stator 20 and the magnetic bearing 30. As shown in FIG. 2, by ensuring a sufficient thickness of the rotor yoke 11, interference between the magnetic flux flowing from the outer stator 20 into the rotor yoke 11 and the magnetic flux flowing from the magnetic bearing 30 into the rotor yoke 11 is prevented. be able to. Specifically, the thickness in the radial direction of the rotor yoke 11 is preferably at least twice the length in the radial direction of the rotor salient pole 12 serving as a magnetic path. Moreover, it is preferable that the thickness in the radial direction of the rotor yoke 11 is equal to or larger than the width in the circumferential direction of the rotor salient pole 12 serving as a magnetic path.

4-6 is a figure which shows the magnetic flux density distribution of the switched reluctance motor 1 in the A point-F point shown in FIG. FIG. 7 is a graph showing the relationship between the output of the switched reluctance motor 1 and the support force of the magnetic bearing 30 in the first embodiment of the present invention.
As is apparent from the magnetic flux density distributions shown in FIGS. 4 to 6, even when the magnetic bearing 30 is operated, the rotor yoke 11 has a sufficient thickness so that the magnetic flux density in the rotor 10 is not saturated. I understand. Further, as shown in FIG. 7, it can be seen that in any switched reluctance motor 1 with a load factor of 75 to 95%, the support force of the magnetic bearing 30 does not affect the output of the switched reluctance motor 1. That is, it can be seen that even if the current flowing through the magnetic bearing 30 increases, the operation can be performed without causing a decrease in the output of the switched reluctance motor 1.

  Thus, according to the above-described embodiment, the rotor 10 having the annular rotor yoke 11 and the rotor salient pole 12 protruding from the outer peripheral surface 11a of the rotor yoke 11, and the outer having the stator coil 23 facing the rotor salient pole 12 are provided. A switched reluctance motor 1 having a stator 20, wherein the rotor yoke 11 has a space portion 13 on the radially inner side and a magnetic bearing 30 disposed in the space portion 13. Thus, the switched reluctance motor 1 and the centrifugal compressor 100 that can secure the installation space of the magnetic bearing 30 and can reduce the size of the entire apparatus can be obtained.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 8 is an overall configuration diagram of the centrifugal compressor 100 according to the second embodiment of the present invention.
As shown in FIG. 8, the second embodiment is different from the above embodiment in that the switched reluctance motor 1 </ b> A has a first magnetic bearing 30 </ b> A and a second magnetic bearing 30 </ b> B.

  The first magnetic bearing 30 </ b> A is arranged on one side (the end on the left side in FIG. 8) of the rotor 10 in the axial direction of the shaft 101. The second magnetic bearing 30 </ b> B is disposed on the other side (the end on the right side in FIG. 8) of the rotor 10 in the axial direction of the shaft 101 (space 13). That is, although not shown in FIG. 8, in the second embodiment, the protrusion 34 of the core 31 is divided into two regions in the axial direction by slits or the like, and the coil 32 is wound around each of the two regions. Thus, a first magnetic bearing 30A and a second magnetic bearing 30B are formed.

  According to the second embodiment having the above-described configuration, the first magnetic bearing 30A and the second magnetic bearing 30B are incorporated into the switched reluctance motor 1A. The first magnetic bearing 30 </ b> A and the second magnetic bearing 30 </ b> B can be subjected to displacement control by the magnetic bearing controller 4. The first magnetic bearing 30 </ b> A and the second magnetic bearing 30 </ b> B are disposed at two locations in the space portion 13 in the axial direction of the shaft 101, and the parallelism of the shaft 101 can be easily adjusted. According to this configuration, since only one switched reluctance motor 1A is required, the entire apparatus can be made smaller than the above embodiment.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above embodiment, the configuration in which the magnetic bearing is an 8-pole heteropolar type is illustrated, but the present invention is not limited to this configuration. For example, a 12-pole heteropolar type, an 18-pole heteropolar type, or the like. It may be. Further, the magnetic bearing may be a monopolar type instead of a heteropolar type.

Moreover, in the said 2nd Embodiment, the structure which arrange | positions a reactor between the 1st magnetic bearing and the 2nd magnetic bearing may be sufficient. That is, a reactor may be formed by winding a coil around a middle protrusion divided into three regions in the axial direction. The reactor forms, for example, a booster circuit for the motor drive device described above. The reactor forming the booster circuit tends to increase in size in order to handle a large current. Therefore, by incorporating this reactor inside the rotor in the radial direction, it can greatly contribute to the miniaturization of the entire apparatus.
In addition, the present invention is not limited to the configuration in which the reactor is used in a booster circuit, and may be used as a step-down circuit, an AC reactor, a DC reactor, or the like. Moreover, when a reactor contains a some coil, you may use each for another use instead of the same use.

  Further, for example, in the above embodiment, a three-phase motor has been described as an example, but the present invention is not limited to this configuration, and can be applied to a two-phase motor, a four-phase motor, a five-phase motor, and the like. it can. In addition, although a 12 / 8-pole structure has been described as an example in a three-phase motor, the present invention is not limited to this number of poles, and may be, for example, a 6 / 4-pole structure or an 18 / 12-pole structure.

  Further, for example, in the above-described embodiment, the switched reluctance rotating machine of the present invention is exemplified as a configuration applied to a centrifugal compressor as an electric motor. However, the present invention is not limited to this configuration and is also applied to a generator. can do. Moreover, in a generator, it can apply suitably for a large sized wind generator as a rotating apparatus. In this case, the load device provided on the shaft is a windmill.

1 Switched reluctance motor (switched reluctance rotating machine)
1A Switched reluctance motor (switched reluctance rotating machine)
10 rotor 11 rotor yoke 11a outer peripheral surface 11b inner peripheral surface 12 rotor salient pole 13 space 20 outer stator 23 stator coil 30 magnetic bearing 30A first magnetic bearing 30B second magnetic bearing 31 core 32 coil 33 yoke 33a outer peripheral surface 34 Protrusion 100 Centrifugal compressor (rotating device)
101 shaft 102 impeller (load device)

Claims (5)

A switched reluctance rotating machine having an annular rotor yoke and a rotor having a rotor salient pole projecting from the outer peripheral surface of the rotor yoke, and an outer stator having a stator coil facing the rotor salient pole,
The rotor yoke has a space portion on the radially inner side,
A switched reluctance rotating machine having a magnetic bearing disposed in the space. The magnetic bearing is
A core having a ring-shaped yoke part and a projecting part protruding from the outer peripheral surface of the yoke part and facing the inner peripheral surface of the rotor yoke with a gap;
The switched reluctance rotating machine according to claim 1, further comprising a coil wound around the protrusion.   The switched reluctance rotating machine according to claim 1, wherein the rotor yoke has a thickness corresponding to a magnetic characteristic of the outer stator and the magnetic bearing. The switched reluctance rotating machine according to any one of claims 1 to 3,
A shaft that rotates via the switched reluctance rotating machine;
And a load device provided on the shaft. The switched reluctance rotating machine is:
A first magnetic bearing disposed on one side of the space in the axial direction of the shaft;
5. The rotating device according to claim 4, further comprising: a second magnetic bearing disposed on the other side of the space portion in the axial direction of the shaft.

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