JPH1084661A - Magnetic levitation motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic levitation motor which can meet the change in output easily and also which is made excellent in the stability of levitation by reducing fluctuation of a magnetic control force acting in the circumferential direction of a rotating shaft. SOLUTION: In this magnetic levitation motor, a control magnetic field of (m) deg. 2 poles is superposed synchronously on a rotation drive magnetic field comprising (m) poles by windings provided in slots of a stator and thereby a force of rotation is given to a rotor, and at the same time, the rotor is controlled to be levitated magnetically by increasing or decreasing the control magnetic field according to the displacement of the rotor detected by a detecting means of the displacement of the rotor. In this case, the stator is constructed of two or more removable stator units 12A, 12B and 12C with connectors 15 connecting the windings interposed, while the rotor is divided (into 13A, 13B and 13C) and so provided in the axial direction as to correspond to the stator units, and thereby regulation of the axial lengths of the stator and the rotor is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic levitation motor having both a motor function for driving a rotating body to rotate and a magnetic bearing function for controlling the magnetic levitation of the rotating body.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publications Nos. 2-193547 and 6-133493 disclose a cylindrical rotor incorporated in a cylindrical stator and an excitation circuit formed in the stator.
Here, a magnetic levitation motor that applies a rotational force to a rotor and simultaneously holds the magnetic levitation at a predetermined position to apply a position control force is disclosed. In this method, a stator is provided with a winding for rotational driving and a winding for control, and a three-phase alternating current is applied to each of them to form a rotating magnetic field having a predetermined number of poles having a different relationship, thereby rotating the cylindrical rotor. The magnetic attraction in the radial direction is deviated on the plane perpendicular to the axis.

Thus, the rotor is magnetically attracted,
In addition to functioning as a motor that applies a rotational force to the rotor, the floating position and attitude of the rotor can be controlled to function as a magnetic bearing capable of supporting the stator in a non-contact floating manner. For this reason, an electromagnet yoke portion and a winding corresponding to a magnetic bearing, which have been conventionally required, are not required, and the shaft length of the rotating machine can be shortened, and the limitation of high-speed rotation from shaft vibration can be reduced. Further, the size and weight of the rotating machine can be reduced. In addition, the operation equivalent to a magnetic bearing can be performed by the synergistic effect of the magnetic field generated by the current of the control winding and the current of the main winding, so that the control force can be reduced with a much smaller current than a conventional magnetic bearing. , And significant energy savings are possible.

As described above, several proposals have been made for the magnetic levitation rotating machine. The drive winding and the position control winding may be different windings, or may be a common winding. Basically, the number of poles m of the motor rotation driving magnetic field and the number n of the flying position control magnetic field are: It is necessary that n = m ± 2.

In designing such a magnetic levitation motor, in order to change the output of the motor, the shaft length, the number of slits, the number of windings, the current capacity, etc. of the rotor and the stator are individually designed, and these are changed. The rotor and stator according to the design must be manufactured separately. Therefore, even if a magnetic levitation motor having a certain output is manufactured, for example, when a magnetic levitation motor having a double or half capacity is required, a stator and a stator corresponding to these target uses are required. The rotor must be redesigned.

In the magnetic levitation motor, for example, a stator forms a four-pole rotating drive magnetic field, and the rotor rotates so as to be pulled by the rotating drive magnetic field. The stator of the conventional magnetic levitation motor is formed with a slot for accommodating a stator winding along the axial direction, and the exciting current supplied to this winding causes, for example, four poles in the circumferential direction. A rotational drive magnetic field is formed. For this reason, a uniform magnetic field acts on the rotor in the axial direction. However, since four magnetic poles are present on the stator side in the circumferential direction, the strength of the magnetic field is exerted on the rotor along the circumferential direction. The ripples are caused to act. For this reason, there is a problem that the magnetic control force for supporting the rotor in the floating state fluctuates in the circumferential direction, and the floating stability is deteriorated.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a magnetic levitation motor that can easily cope with a change in output.

Another object of the present invention is to provide a magnetic levitation motor having excellent levitation stability by reducing fluctuations in magnetic control force acting in the circumferential direction of the rotating shaft.

[0009]

A magnetic levitation motor according to the present invention superposes a control magnetic field of m ± 2 poles synchronized with a rotation driving magnetic field of m poles by a winding provided in a slot of a stator, and rotates the motor. In a magnetic levitation motor that controls the magnetic levitation of the rotor by simultaneously increasing and decreasing the control magnetic field from the displacement of the rotor detected by the displacement detection means while applying a rotational force to the rotor, the stator connects the windings. It is composed of two or more stator units that can be attached and detached via a connector, and the rotor is axially divided and installed corresponding to each of the stator units, and the axial length of the stator and the rotor is set. It is characterized in that the length can be adjusted.

Each of the stator units is installed so as to rotate with respect to the center axis of the stator in units of the angle between the slots, and the connector is installed while rotating the stator about the axis. It is characterized in that the windings passing through the previous slot are connected so as to be continuously connected after rotation.

[0011] Further, the rotor is installed so as to rotate in accordance with the rotation angle of each of the plurality of stator units installed so as to rotate relative to each other.

According to the present invention described above, the stator is composed of two or more stator units that can be attached and detached via the connector for connecting the windings, and the rotor is divided corresponding to the stator unit. Therefore, a magnetic levitation motor having an output that is an integral multiple of the unit stator unit can be easily configured. Thus, it is possible to easily cope with a change in the output of the magnetic levitation motor without re-designing the basic design of the stator and the rotor from the beginning.

Further, since the plurality of stator units are installed so as to rotate with respect to the center axis of the stator in units of the angle between the slots, the magnetic attraction force acting on the rotating shaft along the circumferential direction is obtained. Ripple can be leveled. Therefore, it is possible to reduce the fluctuation of the magnetic control force for supporting the rotor in the circumferential direction along the circumferential direction, and it is possible to provide a magnetic levitation motor having excellent levitation stability.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross section along a rotation axis of a magnetic levitation motor according to one embodiment of the present invention, and FIG. 2 shows cross sections along AA line, BB line, and CC line of FIG. 1, respectively.

In this magnetic levitation motor, three stator units 12A, 12B, and 12C are disposed on a casing 10 so as to be detachable along a rotation axis direction. Each stator unit 12A, 12B, 12C has the same dimensions,
It has slots and windings. A connection line 16 is connected between the stator units 12A, 12B, and 12C via a connection connector 15 attached to each stator unit.
Connected by The stator 12A is provided with connectors 15A and 15B at the start and end of the stator winding. The supplied exciting current depends on the connector 15 at the beginning of winding.
A, the winding of each stator unit is connected to the connector 15B so as to pass through the winding of the stator unit 12A, the winding of the stator unit 12B, and the winding of the stator unit 12C, and circulate to the connector 15B at the end of winding. And the connection line 16.

Each winding of the stator unit is disposed in a slot of the stator yoke. In this embodiment, a rotation driving magnetic field having four poles and a two-pole rotation control magnetic field synchronized with the rotation driving magnetic field are respectively applied to the stator yoke. Is formed on the inner peripheral side of. Rotating shaft 11
Have stator units 12A, 12B, 12
The rotor units 13A, 13B, and 13C facing each other are fixed to the inner peripheral surface side of the stator yoke C through a gap. In this embodiment, each rotor unit is a so-called reluctance rotor having salient poles of a magnetic material.

Therefore, each stator unit is provided with a quadrupole rotation driving magnetic field formed by the exciting current supplied to the winding and a bipolar rotation control magnetic field synchronized with the quadrilateral rotation driving magnetic field on the inner peripheral surface side via a gap. On each rotor unit. Each rotor unit 13A, 13B, 13C has its salient poles rotated and driven by the action of the rotation drive magnetic field, and a magnetic levitation force acts on the rotor units 13A, 13B, 13C. The magnetic levitation position is controlled by distributing the magnetic flux in the circumferential direction.

As shown in FIG. 2, each stator unit is mounted so as to rotate about the center axis of the stator in units of the angle between the slots. In the drawing, Na and Nb indicate main windings that generate a two-phase four-pole rotating drive magnetic field, and + and-indicate winding directions of the windings. Similarly, Na and Nb indicate control windings that generate a bipolar rotating drive magnetic field, and the signs + and-indicate the winding directions of the windings. The number assigned to each slot indicates the slot number. A cross section of the stator unit 12A in FIG. 1 is shown in (A), a cross section of the stator unit 12B is shown in (B), and a cross section of the stator unit 12C is shown in (C).

As shown in the figure, the stator unit 12A is installed so as to rotate by one slot counterclockwise about the stator unit 12B, and the stator unit 12C is positioned at one position with respect to the stator unit 12B. It is installed by rotating clockwise by the amount of the slot. Each rotor unit is also provided with a salient pole portion corresponding to each stator unit and rotated by one slot corresponding to the rotation of the slot of each stator unit.

FIGS. 3A and 3B are cross-sectional views showing the state of connection between the stator units 12A and 12B, and FIG. 3B is a developed view in which the connection portion is developed in the circumferential direction. As shown in the cross-sectional view (A) of the connection portion, the outlet connector 15 of the stator unit 12A and the inlet connector 15 of the stator unit 12B are connected by a connection line 16. And
As shown in the developed view (B), the slots for accommodating the windings of the respective stator units are shifted by one slot in the circumferential direction, and the windings of the same slot number are connected by the connection lines 16 respectively. It is connected between the connectors 15 and 15. Although this relationship is not shown, the stator unit 12
The same applies to the connection between B and 12C.

To explain the winding Na, the winding enters from the left side of the slot position of the stator unit 12A, exits to the right side, is connected to the connector 15, and the slots 3 and 7 are connected to the connector 15 in the drawing. Exit from the right side to the left side of. With respect to the stator unit 12B, the winding Na is wound in the same manner with a shift of one slot. Further, the winding Na is wound in the same manner as the stator unit 12C is also rotated by one slot. The winding Nb, which is the other phase for generating the quadrupole rotation driving magnetic field, is similarly wound with respect to each of the stator units 12A, 12B, and 12C so as to rotate by one slot. And control windings Nα and Nβ for forming a two-pole rotation control magnetic field.
The same applies to.

Accordingly, each of the three stator units 12A, 12B, and 12C configured as described above forms one winding.
Each of the stator units is rotated by a slot and connected to each other, and penetrates each slot. On the other hand, the rotor unit is fixed to the rotating shaft 11 by rotating the salient poles with respect to the corresponding stator units at the same angle as the rotation angle of the slots of the stator.

FIG. 4 shows the magnitude and direction of the magnetic force Fm acting on each rotor. As shown in the figure, since the windings are arranged by rotating one slot (45 °) in each of the stator units 12A, 12B, and 12C, the magnetic poles N and S of the four-pole rotation driving magnetic field are respectively set as shown in the figure. It becomes a rotated positional relationship. Therefore, the vectors of the generated control force Fm acting on the rotating shaft are as shown by arrows.

FIG. 5 is a diagram showing a change in the generation control force Fm along the circumferential direction. As shown, the magnetic control force Fm
Becomes a peak at every rotation angle of 90 ° (π / 2), and the relationship between the peak and the size of the valley is √2: 1. The peaks of the stators 12A and 12C coincide with each other, and the peak of the stator 12B is shifted by 45 ° (π / 4). Therefore, these three stators 12A, 1
The combined control magnetic force Fm of 2B and 12C is 0, π / 4,
2 + √2 in π / 2..., and π / 4, 3 in the middle
With π / 4, 1 + 2√2. Therefore, the variation is √2-1. In the conventional case where the angle of the slot is not shifted,
The variation is 3 (√2-1). Therefore, it becomes ３ of the variation of the total control force generated when the stator and the rotor are not rotated and installed.

In the above embodiment, the number of salient poles of the rotor is also four.
Although the poles are used, it goes without saying that the same can be applied even if the number of poles of the rotor increases. In this embodiment, the reluctance type rotor has been described. However, it goes without saying that the structure of the rotor can be similarly applied to an induction machine type or a permanent magnet synchronous type.

It should be noted that in the above embodiment, the same capacity of 3
Although the example of combining two stator units has been described,
By preparing a plurality of basic stator units and combining them, it is possible to respond to more fine-grained output changes.

[0027]

As described above, according to the present invention, the output can be changed only by changing the combination of the unitized stator and rotor in accordance with the required motor output. As a result, it is possible to reduce the design time and cost of the magnetic levitation motor. Further, by connecting the slots into which the windings are inserted between the stator units while displacing them in the circumferential direction, it is possible to reduce fluctuations in the generated control force according to the rotation angle of the rotating shaft, and to reduce the floating control force. Stabilization can be measured.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along a rotation axis of a magnetic levitation motor according to one embodiment of the present invention.

2A is a cross-sectional view taken along the line AA in FIG. 1; FIG.
Sectional drawing along line B, (C) Sectional view along line CC.

3A is a sectional view of a connection portion between stator units in FIG. 1, and FIG. 3B is a developed view of the connection portion along a circumferential direction.

FIG. 4 is an explanatory diagram of generation control force of the stator units (A), (B), and (C).

FIG. 5 is a graph corresponding to the rotation angle of the generated control force acting on the rotation axis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Casing 11 Rotation axis 12A, 12B, 12C Stator unit 13A, 13B, 13C Rotor unit 15 Connector 16 Connection cable

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadashi Sato 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Prefecture Inside Ebara Research Institute, Ltd. (72) Inventor Naofumi Kajima 4-1-1 Motofujisawa, Fujisawa-shi, Kanagawa No. 1 Ebara Densan Co., Ltd.

Claims (3)

[Claims] 1. A winding provided in a slot of a stator superimposes a control magnetic field of m ± 2 poles synchronized with a rotation driving magnetic field of m poles to apply a rotational force to a rotor and simultaneously detect displacement. The magnetic levitation motor controls the magnetic levitation of the rotor by increasing or decreasing the control magnetic field from the displacement of the rotor detected by the method described above. A magnetic unit, wherein the rotor is axially divided and installed corresponding to each of the stator units, and the axial lengths of the stator and the rotor are adjustable. Levitation motor. 2. The stator unit according to claim 1, wherein said stator unit is rotated relative to a center axis of said stator in units of an angle between said slots, and said connector is mounted to rotate about said stator. 2. The magnetic levitation motor according to claim 1, wherein the winding passing through the previous slot is connected so as to be continuously connected after rotation. 3. The magnetic levitation motor according to claim 2, wherein the rotor is installed by rotating according to a rotation angle of each of the plurality of stator units that are installed by rotating each other.