JP2008178165A - Bearingless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearingless motor shortened in the coil end length of a winding of a rotating machine of a bearingless motor which generates torque and a radial electromagnetic force by a single electromagnetic machine, high in the winding occupation rate of a slot, and improved in magnetomotive force distribution and insulation between a motor winding and a support winding. <P>SOLUTION: A short section concentrated winding is applied to a motor winding M at each tooth 3. The number of coils is four, and the coil is wound a plurality of times. Furthermore, the four coils are connected to one another, and constitute a single-phase winding. Since the support windings SI, SO are formed into toroidal windings, and coil ends of the motor winding M and coil ends of the support windings SI, SO are made not to overlap each other, the coil end length can be shortened. The support windings SI, SO are the fractional-pitch concentrated windings, and a part of the windings is made to wind around the outside of a stator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearingless motor. In particular, the coil end length of a winding of a rotating machine of a bearingless motor that generates torque and radial electromagnetic force in one electromagnetic machine is shortened, and the winding occupation ratio of a slot is reduced. The present invention relates to a bearingless motor that is high and has improved magnetomotive force distribution and insulation between the motor winding and the support winding.

  The bearingless motor is intended to realize the magnetic bearing function and the motor function with a single electromagnetic machine. For example, Fukao Tadashi (President of the Institute of Electrical Engineers of 2003, Professor Emeritus of Tokyo Institute of Technology), Akira Chiba (Professor of Tokyo University of Science) “Bearingless Motor” There are explanations, and the books A. Chiba, T. Fukao, O. Ichikawa, M. Oshima, M. Takemoto and DGDorrell, "Magnetic Bearings and Bearingless Drives", Elsevier Newnes Press, ISBN0-7506-5727-8, As described in 2005.

  That is, it generates electromagnetic force in the biaxial directions of the radial directions x and y and torque for rotation. In order to generate torque, a three-phase winding is applied in the same manner as a general electric motor, and another winding group is required to generate a radial electromagnetic force, which is called a support winding. In general, the support winding often has two poles, four poles, etc., and the coil end length tends to be long. In particular, the coil end length becomes a problem in a thin configuration.

  For example, in a Levitronics bearingless motor, the structure of the temple motor is such that the stator teeth are bent, and even if the coil end length increases, the structure extends in the axial direction.

  As a method for shortening the coil end length, in a general permanent magnet motor, a method of applying a short concentrated winding for each stator tooth has already been actively applied. For example, in the case of a 12-slot stator, a coil with short nodes concentrated on 12 teeth. Corresponding to 12 slots, the number of poles of the rotor is 8, 9, 10, 14, etc.

  FIG. 3 shows a configuration example of a conventional winding. In FIG. 3, the stator yoke 1 forming the stator 10 has 12 teeth projecting inwardly, and the motor winding M (indicated by symbol M in the figure) is short for each tooth 3. It is wound in a concentrated section. However, in FIG. 3, for simplicity, the motor winding M shows only the U phase. The rotor 5 has a permanent magnet 9 embedded between iron core poles 7 arranged at equal intervals, is magnetized to 8 poles, and is a rotor of a continuous pole PM motor. On the other hand, the support windings S (indicated by symbol S in the figure) are arranged in a vertically symmetrical manner with respect to the four slots 11, and the coil ends SE (indicated by symbol SE in the figure) are arranged between them. ) Via distributed winding. However, in FIG. 3, for the sake of simplicity, the support winding S is shown for only one phase, but is actually wound for three phases. Since the coil end SE is long, there is a problem that the winding space factor of the slot is low, and the coil ends overlap between the three phases, so that the axial length is large.

  As a technique suitable for further reduction in thickness, Patent Document 1 discloses a structure in which a toroidal winding is wound around a stator yoke and a short concentrated winding is disposed on a stator tooth. Further, it is described that the output can be improved by arranging a rotor inside and outside the stator.

Further, in Patent Document 2, an electric motor similar to the above-mentioned Japanese Patent Laid-Open is disclosed. A rotor is arranged inside and outside the stator, and windings are wound around the stator yoke.
Patent Document 3 discloses an electric motor that connects a winding wound around the stator teeth and a winding wound around the stator yoke.
In addition, Patent Document 4 discloses a method in which a toroidal winding is applied to a stator yoke and a cut is disposed in the yoke portion.
Patent Document 5 discloses a toroidal winding type single-phase induction motor.
JP 2001-37133 A JP-A-10-271784 JP-A-8-172759 Japanese Patent Laid-Open No. 9-9532 JP 2004-222353 A

  However, in these published patent applications, the target is a single-phase or three-phase motor in which the structure of the motor winding is devised. There is no disclosure of structures that float or suppress vibration by force. Furthermore, a bearingless motor requires four or more phases of windings, and generally two sets of six phases are applied to three phases.

  As described above, the bearingless motor has a winding for operating as an electric motor and a winding for magnetic support. The drive voltages for these windings are not necessarily equal. That is, the electric motor is driven at a high voltage, but the supporting winding requires a small voltage current. For example, the motor winding is 200V and the support winding is 15V. Then, these windings need to be electrically insulated, and it is important that the high voltage side and the low voltage side are not short-circuited in order to prevent the driver from being destroyed even when the insulation is deteriorated. However, there is a high possibility that the high voltage side and the low voltage side are short-circuited because the coil ends overlap between the three phases.

  Further, among the bearingless motors, in the continuous pole type, the homopolar type, the hybrid type, etc., a two-pole winding is indispensable for the supporting winding. In the case of a general electric motor, the coil end length can be shortened by increasing the number of poles. In fact, the coil end length of the motor winding of these bearingless motors can be made compact by increasing the number of poles. However, since the support windings of these bearingless motors need to have two poles, they cannot be multipolarized. For this reason, there was a problem that the winding of the coil end was long.

  The present invention has been made in view of such a conventional problem, and while shortening the coil end length of the winding of the rotating machine of the bearingless motor that generates torque and radial electromagnetic force in one electromagnetic machine, An object of the present invention is to provide a bearingless motor having a high slot occupancy ratio and improved magnetomotive force distribution and insulation between a motor winding and a support winding.

  For this reason, the present invention (Claim 1) is provided with a plurality of motor windings arranged inside and / or outside the stator, and a number of poles independent of the motor windings and different from the motor windings. The magnetic support winding includes a toroidal support winding coil that is toroidally wound on the yoke of the stator, and the inner conductor of the toroidal support winding coil is It is passed through a yoke inner slot formed inside the yoke, and the outer conductor of the toroidal support winding coil is passed through a yoke outer slot formed outside or outside the yoke.

  The magnetic support winding is a toroidal winding so that the coil end of the motor winding and the coil end of the magnetic support winding do not overlap. The coil end has a thickness at the stator yoke portion, can be separated from the coil end of the motor winding, and the axial length of the coil end can be shortened. There is no possibility that the coil ends overlap between the three phases, and a sufficient separation distance can be maintained between the high-voltage side winding and the low-voltage side winding. For this reason, these windings are electrically insulated, and it is difficult for the high voltage side and the low voltage side to be short-circuited even during insulation degradation.

Further, according to the present invention (Claim 2), the motor winding is disposed inside and / or outside the stator, and the inner conductor of the toroidal support winding coil is a yoke inner slot formed inside the yoke. The outer conductor of the toroidal support winding coil is passed through a yoke outer slot formed outside or outside the yoke.
Further, according to the present invention (Claim 3), the magnetic support winding includes an adjustment coil that is short-spot concentrated and wound around teeth toward the inside and / or outside of the stator, and / or between the yoke inner slots. Distributed winding coils distributed between the yoke outer slots or between the yoke outer slots are mixed with the toroidal support winding coils.

  In order to improve the magnetomotive force distribution, adjustment coils and distributed winding coils may be mixed in addition to the magnetic support winding. The adjusting coil is wound around the teeth in a concentrated manner, and the distributed winding coil is wound so as to cross between slots formed inside and outside the yoke.

Further, according to the present invention (Claim 4), the motor winding is characterized in that a short concentrated winding is applied to teeth arranged on the inside and / or outside of the stator.
In the motor winding, the coil end is shorter in the short concentrated winding than the coil pitch is long. The coil end is thick at the stator teeth.

Further, according to the present invention (Claim 5), a rotor is provided inside and / or outside the stator.
The windings can be arranged on the outer circumference of the stator, teeth can be formed on the outer circumference of the stator, the windings can be arranged there, and the outer rotor can be arranged on the outer circumference. In this configuration, the magnetomotive force of the conductor arranged outside the stator can be effectively used for generating radial force electromagnetic force. If there are two of an outer rotor and an inner rotor, a so-called double rotor structure can be formed. If the inner rotor is omitted, a simple outer rotor configuration is obtained. Even in this case, the stator coil end length is shortened.

Furthermore, the present invention (Claim 6) is characterized in that the number of poles of the magnetic support winding is two, and is a continuous pole type, a homopolar type, or a hybrid type.
Among the bearingless motors, in the case of a continuous pole type, a homopolar type, a hybrid type, etc., a two-pole winding is indispensable for the supporting winding. For this reason, there was a problem that the winding of the coil end was long. It can be made compact by toroidally winding the stator yoke.

  As described above, according to the present invention, the magnetic support winding is configured to have the toroidal support winding coil that is toroidally wound around the yoke of the stator. Does not overlap with the coil end. The coil end has a thickness at the stator yoke portion, can be separated from the coil end of the motor winding, and the axial length of the coil end can be shortened. There is no possibility that the coil ends overlap between the three phases, and a sufficient separation distance can be maintained between the high-voltage side winding and the low-voltage side winding. For this reason, these windings are electrically insulated, and it is difficult for the high voltage side and the low voltage side to be short-circuited even during insulation degradation.

  Hereinafter, embodiments of the present invention will be described. In the first embodiment of the present invention, the coil end length is shortened by devising the winding configuration of the bearingless motor. As for a motor winding of a bearingless motor, the number of rotor poles may be increased as in a general permanent magnet motor, and a short concentrated winding may be provided for each stator tooth. However, the following two types of support windings are conceivable. There are a system in which a p ± 2 pole winding is applied to a p pole such as an induction machine or a permanent magnet, and a system in which a 2 pole winding such as a consequent pole, hybrid, or homopolar is applied. The present invention is a winding technique common to both methods. In the following description, a case of two poles where the coil end length is particularly large will be described. However, the present invention can be realized with an even number of poles such as 4, 6, and 8. In particular, the coil end length can be shortened by devising so that the motor winding and the coil end do not overlap.

FIG. 1 shows a configuration diagram of the first embodiment of the present invention. Note that the same elements as those in FIG.
FIG. 1 shows an embodiment of the present invention corresponding to FIG. 3 which is a conventional method. In the following, an embodiment is shown for a 12-slot stator, but it can be realized for any number of slots. The motor winding M is provided with a short concentrated winding for each tooth 3 as in the prior art. There are four coils, which are wound a plurality of times. Further, the four coils are connected to each other to form a one-phase winding. Other two-phase symmetrical coils not shown are wound to form a three-phase winding. Of course, motor windings such as single phase, two phase, four phase, five phase, and six phase may be used.

  On the other hand, the support winding S corresponding to the magnetic support winding has a conductor SO arranged on the outer side of the stator 10 and is paired with the inner conductor SI to form a toroidal winding for winding the stator yoke 1. Yes. In FIG. 1, one phase for three phases is shown, and one phase is composed of the upper four slots and the lower four slots. SI and SO are wound several times. The outer conductor SOR is described in detail for one slot 11 as being wound a plurality of times. Although eight coils are configured in total, the number of turns need not be all equal, and the number of turns is adjusted to improve the support force characteristics. Further, if all 12 slots are used per phase, the magnetomotive force distribution can be further improved.

In such a configuration, since the support windings SI and SO are toroidal windings and the coil ends of the motor winding M and the support windings SI and SO are not overlapped, the coil end length can be shortened. The support windings SI and SO are short concentrated windings, and a part of the windings are wound around the outside of the stator.
As a result, there is no possibility that the coil ends overlap between the three phases, and a sufficient separation distance can be maintained between the high-voltage side winding and the low-voltage side winding. For this reason, these windings are electrically insulated, and it is difficult for the high voltage side and the low voltage side to be short-circuited even when the insulation is deteriorated.

  In addition, even if two pole windings are indispensable for the support winding in the consequent pole type, homopolar type, hybrid type, etc., the support windings SI, SO are made toroidal windings, The coil end length is short and compact.

In order to improve the magnetomotive force distribution and make it sinusoidal, in addition to the support windings SI and SO, as shown in FIG. 1, the magnetomotive force by the support windings SI and SO (in FIG. 1, the horizontal direction) The winding SC can be wound around the tooth 3 simultaneously so as to act in the direction of adjusting Winding SC corresponds to the adjustment coil.
In this case, the windings SC are arranged so as to be vertically symmetrical with respect to the horizontal direction in FIG. 1, and are specifically wound around the left and right teeth 3 in the drawing.

Next, another example of this embodiment will be described.
In FIG. 1, it has been described that the magnetomotive force distribution is improved by simultaneously winding the winding SC together with the supporting windings SI and SO. However, a part of the supporting windings SI and SO are already shown in FIG. The magnetomotive force distribution can be improved by using the winding S or by providing the support winding S with distributed winding in addition to the support windings SI and SO and the winding SC.

  Thus, by appropriately combining the support winding S, the support windings SI, SO, and the winding SC and determining the number of turns, an appropriate magnetomotive force distribution can be obtained with a small coil end. That is, the distributed winding shown in the support winding S, the toroidal winding of the yoke shown in the support winding SI, SO, and all or part of the concentrated short-tooth winding of the tooth shown in the winding SC are combined to reduce the number of distributed windings as much as possible. Thus, the coil end is reduced to obtain a desired magnetomotive force distribution. At this time, it is not necessary for each winding to realize a sine wave distribution.

Next, a second embodiment of the present invention will be described.
The second embodiment of the present invention comprises an outer rotor and a double rotor in order to effectively use the support winding SO portion arranged on the outside of the support windings SI and SO. FIG. 2 shows a configuration diagram of the second embodiment of the present invention. Note that the same elements as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 2, the stator yoke 1 forming the stator 20 has 12 teeth projecting outwardly symmetrically with the inner teeth 3 and motor winding MO (indicated by symbol MO in the figure). ) Is wound around each tooth 23 by a short concentrated winding. However, in FIG. 2, for simplicity, the motor winding MO shows only the U phase. In addition, a permanent magnet (not shown) is embedded toward the teeth 23 between the core poles 27 arranged at equal intervals on the inner side of the outer rotor 25. Further, similarly to FIG. 1, a winding SC (not shown) is wound around each tooth 23 by a short concentrated winding.

As described above, the outer slot 21 may be combined with the motor winding MO, the support winding SO, the winding SC, and all or a part of the support winding S shown in FIG. Supporting force and torque can be improved and increased.
Further, only the outer rotor may be used instead of the double rotor as shown in FIG. In this case, inner teeth and windings may be omitted.

  Examples of application of the bearingless motor of the present invention include generators such as micro gas turbines, flywheel motor generators, pumps, blowers, compressor drives, air conditioners, home appliances, computer equipment drives, automobile turbo generator motors It can be applied to bioreactors, semiconductor manufacturing equipment, electric motors in vacuum containers, electric motors in special gases and liquids.

Configuration diagram of the first embodiment of the present invention Configuration diagram of second embodiment of the present invention Example of winding structure of a conventional bearingless motor

Explanation of symbols

1 Stator Yoke 3, 23 Teeth 5 Rotor 7, 27 Iron Core 9 Permanent Magnet 10, 20 Stator 11, 21 Slot 25 Outer Rotor M, MO Motor Winding S Support Winding SC Winding SE Coil End SI Supporting Winding Wire (inner conductor)
SO Support winding (outer conductor)
SOR Support winding (individual lead)

Claims (6)

A bearingless motor comprising a multi-pole motor winding disposed on a stator and a magnetic support winding disposed independently of the motor winding and having a different number of poles from the motor winding;
The bearingless motor according to claim 1, wherein the magnetic support winding includes a toroidal support winding coil that is toroidally wound around the yoke of the stator. The motor windings are arranged on the inside and / or outside of the stator;
The inner conductor of the toroidal support winding coil is passed through a yoke inner slot formed inside the yoke, and the outer conductor of the toroidal support winding coil is passed through a yoke outer slot formed outside or outside the yoke. The bearingless motor according to claim 1. The magnetic supporting winding is distributed between the yoke inner slots or between the yoke outer slots, and / or the adjustment coil wound in a concentrated manner on the inner and / or outer teeth of the stator. The bearingless motor according to claim 1, wherein the distributed winding coil wound is mixed with the toroidal support winding coil. 4. The bearingless motor according to claim 1, wherein the motor winding is provided with a short concentrated winding on teeth arranged on the inside and / or outside of the stator. The bearingless motor according to claim 1, wherein a rotor is provided inside and / or outside the stator. The bearingless motor according to claim 1, wherein the number of poles of the magnetic support winding is two, and is a continuous pole type, a homopolar type, or a hybrid type.

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