JP3374196B2 - Rotating electric machine stator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator of a rotary electric machine such as a three-phase induction motor, and more particularly to a support for supporting and fixing a winding housed in a slot provided in a stator core. It concerns materials.

[0002]

2. Description of the Related Art Conventional rotary electric machines (hereinafter referred to as conventional machines)
In the stator core in, the winding with insulation is housed in the slot provided in the core, and in many cases the non-magnetic support is used to prevent the winding from falling into the opening of the slot. A material, a so-called wedge, is inserted. In this case, the magnetic resistance of the slot opening is larger than that of the iron core.
Most of the magnetic flux is concentrated and distributed in the teeth of the iron core. It is known that the magnitude of the maximum magnetic flux density in each tooth of the iron core differs depending on the position of the tooth of the iron core on the circumference of the void, and the magnitude relation between them has regularity along the circumference of the void.

FIG. 1 shows an example of the maximum magnetic flux density (conventional machine) in each tooth of the iron core of the stator. As shown in FIG. 1, the magnetic flux density of the iron core tooth portion 7 in the tooth portion numbers # 4 and # 6 indicating the circumferential position of the stator iron core is the largest in the tooth portion number # 6 as compared with the tooth portion number # 4. The magnetic flux density becomes high and the iron loss becomes large. This is because the magnetomotive force distribution generated by the winding current is stepwise and the current phases of the windings 5 inserted in the slots 4 located on both sides of the tooth number # 4 are equal. This is because the current phases of the windings 5 in the slots 4 located on both sides of the tooth number # 6 are different. Further, this phenomenon is caused by, for example, in a rotary electric machine provided with a three-phase winding, 6m ± first order (here, in the case of 6m + 1, m =
0, 1, 2, ..., In the case of 6m-1, m = 1, 2,
, Which is a cause of the generation of the spatial harmonic magnetic flux, and has a problem of increasing the harmonic loss in the rotor core.

By the way, all the support materials have a relative magnetic permeability of 1
When a larger material, that is, a magnetic support material is used, the magnetic flux can pass through the support material portion as well, so that it is possible to reduce the concentration of the magnetic flux on each core tooth portion. However, also in this case, as in the case of using the above-mentioned non-magnetic support material, in the iron core tooth portions at the positions where the phases of the currents flowing in the windings in the adjacent slots of the stator winding are different from each other, The maximum magnetic flux density is higher than that of other teeth of the iron core.

As a method for solving the above-mentioned problems, for example, a method of setting the cross-sectional area of each iron core tooth portion so that the maximum magnetic flux densities of each iron core tooth portion are substantially equal is disclosed in Japanese Patent Laid-Open No. 53-53.
No. 129805, and a method for setting the void length in each iron core tooth portion in order to obtain the same effect is disclosed in JP-A-54-2.
It is disclosed in Japanese Patent No. 3915. The former is the maximum magnetic flux density in the in-phase current inter-tooth portion 9 and the maximum magnetic flux density in the different-phase inter-current tooth portion 9 at a position where the phases of the currents flowing through the windings in the adjacent slots of the stator windings are different from each other. The width dimension of each tooth portion of the iron core is changed so that On the other hand, the latter is characterized in that the air gap size in the core teeth is different so that the maximum magnetic flux densities in the core teeth 7 are almost equal.

[0006]

In the above prior art, in the former case, since the width dimension of each stator core tooth portion 7 is different depending on the location, the straddling of the winding over the two slots of the stator core is performed. The pitch becomes uneven. Therefore, winding 5
Since the magnetomotive force distribution due to becomes uneven and a new harmonic magnetic flux is generated, it is considered insufficient to reduce the harmonic loss. On the other hand, the latter changes the air gap size of the iron core tooth portion depending on the phase relationship of the currents flowing through the windings 5 in the slots 4, so that, for example, in a rotary electric machine having a short air gap length represented by an induction motor, extremely high working accuracy is required. It will be required and will be difficult to manufacture.

In view of the above points, the object of the present invention is to adjust the magnetic flux passages so that the maximum magnetic flux densities of the air gaps at the stator core tooth end are substantially equal, without depending on the special working precision. An object of the present invention is to provide a stator of a rotating electric machine, which can reduce iron loss of a stator of the rotating electric machine and harmonic loss in a surface portion of a rotor core, and contribute to improvement of characteristics such as high efficiency in the rotating electric machine.

[0008]

In order to achieve this object, a rotary electric machine in which a stator and a rotor are opposed to each other via a gap.
Winding in multiple slots in the machine stator core
The winding and support the winding at the slot opening.
Has a supporting material that determines the relative magnetic permeability of the supporting material is greater than 1.
Using a threshold material, there is a difference in the current phase in adjacent slots.
The cross-sectional area of the support material of the slot at
Cross-sectional area of the support material of the slot where the current phase in the slot is the same
The configuration is larger than that.

As a result, the support placed in the slot opening is provided.
The material is the same as supporting and fixing the windings housed in the slots.
Sometimes, adjusting the magnetic resistance in the direction that connects the core teeth
Play a role of changing the spatial harmonic magnetic flux
It will be possible. And the magnetic resistance in the direction that connects the core teeth
Can be small at the boundary between the phases and large at the center of the phase
Yes, it is easy to grow in the teeth of the iron core located at the boundary between phases
The maximum magnetic flux density is suppressed and each space at the end of the stator core tooth is reduced.
The gap magnetic flux density can be made almost equal. Therefore, the core teeth
There is no need to change the void size of the
The iron loss of the stator of the rotating electric machine and the surface of the rotor core.
Higher efficiency in rotating electrical machines by reducing harmonic loss in
It is possible to improve characteristics such as conversion.

Further, the support material is cut on the side in contact with the winding.
If the cross-sectional area is adjusted by incorporating the
The shape of attachment to the iron core tooth portion can be made uniform.
In addition, the support material has a large cross-sectional area by increasing the thickness toward the void side.
With a finer structure, the support material can be attached to the teeth of the iron core.
In addition to being able to make the shape uniform, further cross section
The rate of product change can be increased.

Further , in order to achieve this purpose, a void is formed.
The stator of the rotating electric machine in which the stator and the rotor face each other via the
We store winding in plural slots provided in iron core,
Support for fixing and fixing this winding at the slot opening
It has a wood, composed of a material having a magnetic anisotropy of the support member
The magnetic force in the direction that connects the stator core teeth surrounding the slots.
The support material of the slot at the position of maximum resistance is
Is the minimum relative permeability and the stator core teeth surrounding the slot
Of the slot at the position that minimizes the magnetic resistance in the direction connecting
The support material is configured to have the maximum relative magnetic permeability in the above direction.

With such a configuration, the screen
The support material for the lot opening is stored in the slot.
The direction to connect and fix the core core teeth while supporting and fixing the winding
The spatial harmonic flux is changed by adjusting the magnetic resistance of
It becomes possible to carry out the function of making it. And iron core teeth
The magnetic resistance in the direction that connects the parts is small at the boundary between the phases.
It can be taken large in the central part and is located at the boundary between phases
It is fixed by suppressing the maximum magnetic flux density, which tends to become large at the teeth of the iron core
The air gap magnetic flux densities at the teeth of the child core can be made almost equal.
It Therefore, it is not necessary to change the void size of the iron core teeth.
In addition, the iron loss of the rotating electric machine stator does not depend on special work precision.
And harmonic loss on the surface of the rotor core are reduced.
Therefore, it is possible to improve characteristics such as high efficiency in the rotating electric machine.

Further, the slot at the position where the magnetic resistance is minimized
The support material for the magnetic field has magnetic anisotropy and is better than other support materials.
If it is made of a material with a high relative permeability,
Can be used as a support material having a larger relative magnetic permeability.
it can.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIGS.

FIG. 1 shows a first embodiment according to the present invention 2
It is a sectional development view of the stator of the three-phase induction motor of layer winding. Windings 5 are stacked in two layers and housed in a plurality of slots 4 provided in a stator core 3 of a rotating electric machine in which a stator 1 and a rotor 2 are arranged so as to face each other via a gap. A support member for supporting and fixing the winding 5 in the slot 4, a so-called wedge 6, is inserted into the opening of the slot 4 and connects the stator core tooth portions 7.

The current flowing through the winding 5 has three phases, which are usually represented by U phase, V phase and W phase. The relationship between the phases of the currents flowing in the upper and lower windings in each slot is determined by the combination of the number of slots in the stator, the number of phases (3 in this case), and the winding spanning pitch. There are various combinations of the current phases of the upper and lower windings for each upper position, such as different adjacent slots or several consecutive same combinations. The single layer full-pitch winding and the current conditions are similar. Even in the case of full-pitch winding, the phase boundaries (the tooth numbers # 1, # 4, and # 7 in FIG. 2 correspond to each other) always cause different phases of currents flowing in the adjacent slots. Figure 1
As shown in Fig. 7, the maximum magnetic flux density of the air gap at the tip of the tooth in the case of the same support material of all slots and the same tooth shape adopted in the conventional machine is as follows.
(Tooth number # 1, # 4, # 5, # 8 in FIG. 1 corresponds) The maximum magnetic flux density of the air gap is the tooth portion 9 sandwiched between slots having different current phases (in the case of FIG. Part number # 2, # 3
# 6 and # 7 are equivalent). This means that spatial harmonic magnetic flux is generated, which causes an increase in harmonic loss at the surface of the rotor core. Further, the proximity of the frequency of the spatial harmonic magnetic flux to the frequency of the natural vibration of the iron core tooth portion causes magnetic noise.

As shown in FIG. 1, slots at positions where there is a difference in phase of the currents flowing through the windings 5 in the adjacent slots 4 (in the case of FIG. 1, slot numbers # 2, # 3, # 4, # 6). ，
# 7 and # 8 are equivalent to the support material, slots at other positions,
That is, the slots in which the phases of the currents flowing through the windings 5 in the adjacent slots 4 are equal (in the case of FIG. 1, the slot number #
1, # 5, # 9), that is, a support material having a smaller magnetic resistance in the direction connecting the tooth portions than the high magnetic resistance support material 10. In the case of this embodiment, the support member 6 has a relative magnetic permeability of 1
Slots (# 2, # 3, # 4, # 6, # where there is a difference in current phase in adjacent slots using a larger material)
The magnetic resistance is reduced by increasing the cross-sectional area of the support material of No. 7, # 8). In the case of the winding shown in FIG. 1, the supporting material for the slots (# 3, # 7) in which the in-phase currents flow in the upper and lower layer windings, that is, the low magnetic resistance supporting material 11 is used for the other slots (# 2, # 2).
# 4, # 6, # 8) support material, that is, medium magnetoresistive support material 1
It is desirable to make the cross-sectional area larger than 2.
The measurement result in one example is leveled with respect to the circumferential position of the void portion as shown in the maximum magnetic flux density according to the present invention in FIG. 1, and also has a positive effect on the iron loss distribution. It shows that the wave loss is significantly reduced compared to the conventional model. In the embodiment of FIG. 2, slot numbers # 1, # 2, #
4, the support materials of # 5, # 7, and # 8, that is, the low magnetic resistance support material 11 has a larger cross-sectional area than the support materials of the slot numbers # 3, # 6, and # 9, that is, the high magnetic resistance support material 10. The case where a molded material having a relative magnetic permeability greater than 1 is shown.

The effect of the present invention will be specifically described with reference to FIG. In order to make the explanation easy to understand, only the low magnetic resistance support material 11 of slot number # 3 (see FIG. 1) is used as the magnetic support material, and the high magnetic resistance support materials 10 of # 1, # 2, # 4, and # 5 are used. Shown as a non-magnetic support. The tooth portions of the iron cores having the tooth numbers # 2 and # 3 (see FIG. 1) are the tooth portions 9 between the out-of-phase currents, and the tooth number #
Reference numerals 1 and 4 (see FIG. 1) are common-mode current tooth portions 8. Figure 3
Indicates the direction of the magnetic flux φ, where φt is the magnetic flux passing through the iron core tooth portion, φw is the magnetic flux passing through the support member 6, and φ
e represents a leakage magnetic flux that magnetically shorts around the slot. For example, since the high magnetic resistance support material 10 of the slot numbers # 1 and # 2 uses a non-magnetic support material, the magnetic resistance value of the slot 4 portion is larger than that of the iron core portion and the iron core tooth of the tooth number # 1. The magnetic flux φt concentrates on the part. On the other hand, since the low magnetic resistance support material 11 of slot number # 3 uses a magnetic material having a relative magnetic permeability greater than 1, the magnetic flux φ
As shown by w, the low magnetic resistance support material 1 is also provided in the slot opening.
The magnetic flux will pass through 1. As a result, the magnetic flux concentration in the interphase current tooth portion 9, which has been a problem in the related art, is relaxed, and the maximum magnetic flux density in the interphase current tooth portion 9 becomes approximately the same as that of another iron core tooth portion, that is, the in-phase current tooth portion 8. Can be lowered to. However, the magnetic flux around the slot is φt
And not only the magnetic flux indicated by φw (or the opposite direction). For example, in the magnetic flux generated by the stator winding 5 in the slot number # 3, there is a leakage magnetic flux indicated by φe, which has a large influence when the polarity of the rotating magnetic field is reversed. Therefore, if the magnetic reluctance of the low magnetic reluctance support member 11 is excessively reduced in order to increase the magnetic flux φw, the amount of magnetic flux reaching the rotor side is reduced, and the leakage magnetic flux φe that magnetically short-circuits around the slot is generated. Will be excessively increased, and the characteristics of the electric motor will be deteriorated.

FIG. 4 shows that the cross-sectional shape of the supporting member 6 is devised so that the mounting shape of the supporting member 6 on the iron core tooth portion 7 can be made uniform. By making a cut on the side in contact with the winding and adjusting the size,
It is possible to arbitrarily select the magnetic resistance in the direction connecting the iron core tooth portions 7. If it is necessary to consider the mechanical strength, the cut may be rounded such as an arc instead of the shape having an acute angle. Further, it is not necessary to strictly select the relative magnetic permeability of the support material 6 to which this manufacturing method is applied, and the support material 6 having the optimum magnetic effect can be obtained. Further, since the support member 6 having the magnetic resistance value designated for each slot can be discriminated by the difference in the cut shape, it is possible to prevent an assembly error when the support member 6 is mounted in the opening of the slot 4. .

In FIG. 5, the cross-sectional shape of the support member 6 is devised so that the support member 6 can be attached to the iron core portion 7 in a uniform shape so that the rate of change in cross-sectional area can be made larger than in the embodiment of FIG. It is the one. That is, when a large cross-sectional area is taken, the thickness is increased toward the void side. FIG. 5 shows a low magnetic resistance support material 1 having a large cross-sectional area in slot numbers # 3 and # 7.
1 shows the case where the high magnetoresistive support material 10 having a small cross-sectional area is applied to the other slot numbers, but the slot numbers # 2, # 4, # 6, and # 8 are the same as in the case of FIG. Of course, it is possible to substitute the medium magnetoresistive support material 12 having a specific cross-sectional area. It is also possible to adjust the magnetic resistance by providing the notch described in FIG. 4 with respect to the support member 6 having this shape.

A second embodiment will be described with reference to FIGS. 6 and 7. The structure other than the support member 6 is the same as that of FIG. 1, and the concept of changing the magnetic resistance in the direction connecting the tooth portions in accordance with the phase difference of the current flowing through the windings in the adjacent slots 4 is also the same. . In this embodiment, the support material 6 is made of a material having magnetic anisotropy. The same magnetic anisotropic material is used, and the high magnetic resistance support material 10 (slot numbers # 1, # 5, # that maximizes the magnetic resistance in the direction connecting the teeth) is used.
In 9), the molding is performed so that the relative magnetic permeability becomes the minimum in the direction. Further, the low magnetic resistance support material 11 (slot numbers # 3, # 7) that minimizes the magnetic resistance in the above direction is molded so that the relative magnetic permeability becomes maximum in the above direction. The medium magnetic resistance support member 12 (slot numbers # 2, # 4, # 6, # 8) for setting the magnetic resistance in the above direction to an intermediate value has an intermediate direction between the maximum and minimum relative permeability in the above direction. To process. As shown in FIG. 7, when the selection of the value of the magnetic resistance may be two types, only the direction in which the relative permeability is maximum and minimum is selected to improve the material yield. The same structure can be applied to the three-phase, single-layer, full-pitch winding stator as in the first embodiment. The material having magnetic anisotropy is obtained, for example, by incorporating iron powder into a resin, laminating iron wires and the like in parallel with the direction of maximum relative magnetic permeability, and integrally molding.

A third embodiment will be described with reference to FIG. As a method of changing the value of the magnetic resistance in the direction connecting the tooth portions into two types, the high magnetic resistance support member 10 (slot numbers # 1, #
5, # 9) a conventional non-magnetic support material, and a support material 6 having a small magnetic resistance, that is, a low and medium magnetic resistance support material 1 in this case.
1, 12 (slot numbers # 2, # 3, # 4, # 6, #
7 and # 8), a support material composed of a material having a large relative magnetic permeability and magnetic anisotropy is used. Further, instead of the high magnetic resistance support material 10 made of a non-magnetic material, a support material made of a material having a relative magnetic permeability larger than 1 is used, and the low magnetic resistance support material 11 made of a magnetic anisotropic material has a higher relative magnetic permeability. It can be a support having a large value. This configuration is the first
Similar to the above embodiment, it can be applied to three-phase, single-phase and full-pitch winding.

As described above, the stator of the rotary electric machine according to the present invention adjusts the magnetic flux distribution so as to equalize the maximum air gap magnetic flux density of the stator core tooth portions. The combination of a conventional non-magnetic support material for the high reluctance support material 10 and a suitable magnetic anisotropic support material for the low reluctance support material 11 reduces the leakage flux φe over the conventional non-magnetic support material. In addition, the effective magnetic flux φw passing through the magnetically anisotropic support material to the rotor side can be increased, and as a result, the iron loss generated at the interphase current tooth portion 9 can be significantly reduced.
Further, since the above-mentioned spatial harmonic magnetic flux generated in the conventional stator is reduced, it is possible to obtain an efficient rotating electric machine. Furthermore, if a magnetic field analysis such as the finite element method is carried out and the magnetic flux distribution around the slot opening is examined in detail and the magnetic characteristics of the magnetic anisotropic support material can be optimally selected,
Support materials other than the slots (# 3, # 7) between the different phase current tooth portions 9, that is, in this case, the high-medium magnetic resistance support materials 10, 1
2 makes it possible to use conventional non-magnetic support materials.

When the support members 6 of all the slots are made of a support member having a relative magnetic permeability of more than 1, the core magnetic tooth portions are more prominent than the case where a non-magnetic support member is used as the high magnetic resistance support member 10. It is possible to reduce the concentration of magnetic flux. For this reason, it becomes possible to make the machine more compact and higher in output. In the rotary electric machine having the open slot structure, the rotor core facing the stator core via the support member 6 and the gap is discontinuous because the magnetic distribution of the magnetic resistance between the stator core and the rotor core is discontinuous. The magnetic flux distribution in the circumferential direction of the air gap on the surface of the iron core causes considerable pulsation. This pulsating component is a high-frequency magnetic flux component, which is one of the causes of increasing noise in the rotating electric machine having an open slot structure and increasing harmonic loss on the surface of the rotor core. The stator of the rotating electric machine in which the relative permeability of the support members 6 of all the slots is made larger than 1 and the maximum air gap magnetic flux density distribution at the tips of the stator core teeth 7 is made uniform is the magnetic resistance at the opening of the slot 4. Since the value significantly decreases and the effective magnetic flux also passes through the opening, the pulsating component of the magnetic flux distribution in the circumferential direction of the air gap in the surface portion of the rotor core facing, that is, the harmonic magnetic flux component decreases,
Noise and harmonic loss can be reduced.

The above description of the embodiments has been made by taking a three-phase induction motor having an open slot structure as an example.
It goes without saying that the present invention can be applied to all rotary electric machines having the slot opening and the support member 6 for the winding in the slot opening. Although the effect of the present invention has been described along the cross section of the rotating electric machine stator in the present embodiment, a plurality of support materials 6 having different magnetic resistances are combined in the axial direction of the stator and arranged in the slot opening. Thus, it is possible to maximize the magnetic effect according to the present invention.

[0026]

According to the present invention, the magnetic resistance in the direction connecting the stator core teeth of the support member is fixed by simply changing the magnetic resistance corresponding to the phase difference between the currents flowing through the windings in the adjacent slots. Since the maximum magnetic flux densities of the air gaps at the teeth of the child core can be made almost equal, iron loss and harmonic loss on the surface of the rotor core can be reduced without relying on special machining accuracy, and high efficiency in rotating electrical machines can be achieved. It is possible to provide a stator of a rotary electric machine that can contribute to improvement in characteristics such as improvement in performance.

[Brief description of drawings]

FIG. 1 is a sectional development view of a stator of a two-layer winding three-phase induction motor showing a first embodiment according to the present invention.

FIG. 2 is a sectional development view of a stator of a single-layer full-pitch three-phase induction motor showing a first embodiment according to the present invention.

FIG. 3 is an explanatory diagram showing a specific effect of the present invention.

FIG. 4 is a sectional shape view of a support material showing an embodiment according to the present invention.

FIG. 5 is a cross-sectional development view of a stator of a three-phase induction motor, which also shows a cross-sectional shape of a support material showing an embodiment according to the present invention.

FIG. 6 is a sectional development view of a stator of a three-phase induction motor showing an example of a support material made of a magnetic anisotropic material.

FIG. 7 is a sectional development view of a stator of a three-phase induction motor showing another embodiment of a support material made of a magnetic anisotropic material.

[Explanation of symbols]

1 stator 2 rotor 3 Stator core 4 slots 5 windings 6 Support material 7 Iron core teeth 8 In-phase current between teeth 9 Interphase current tooth 10 High magnetic resistance support material 11 Low magnetic resistance support material 12 Medium magnetic resistance support material

Front page continued (72) Inventor Haruo Obaraki 1-1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Kazumasa Ide 7-1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi, Ltd., Hitachi Research Laboratory (72) Inventor Kenzo Kajiwara, 1-1 1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd., Hitachi, Ltd. (56) References JP-A-63-87146 (JP, A) Actually open 60-138384 (JP, U) Actually open 57-98153 (JP, U) Actually open 59-122741 (JP, U) Actually open 59-126556 (JP, U) Actually open 62-88432 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 3/487-3/493 H02K 1/02 H02K 1/16

Claims (5)

(57) [Claims] 1. A winding is accommodated in a plurality of slots provided in a stator core of a rotating electric machine in which a stator and a rotor are opposed to each other with a gap therebetween, and the winding is provided in the opening of the slot. Has a supporting material for supporting and fixing in, and the relative magnetic permeability to the supporting material.
Using a material with a value greater than 1 and the current level in adjacent slots
The cross-sectional area of the support material of the slot at the position where the phase difference is
Supporting slots at positions where the current phases in the slots are the same
A stator for a rotating electric machine, characterized in that it is made larger than the cross-sectional area of the material . 2. The support member according to claim 1,
Make a cut on the side that contacts the winding to adjust the cross-sectional area.
A stator for a rotating electric machine, characterized by 3. The support member according to claim 1,
Increase the thickness toward the void side to increase the cross-sectional area
A stator of a rotating electric machine characterized by. 4. The stator and the rotor are opposed to each other through a gap.
Slots provided on the stator core of a rotating electric machine
Housing the winding in the slot and place the winding in the slot opening.
A supporting member for supporting and fixing the slot , the supporting member is made of a material having magnetic anisotropy, and the supporting member surrounding the slot is fixed.
Position where the magnetic reluctance in the direction that connects the dentator core teeth is maximized
The support material of the slot of the above has the minimum relative permeability in the above-mentioned direction.
The direction of connecting the stator core teeth surrounding the slot.
The support material of the slot at the position where the magnetic resistance is minimized is
A stator of a rotating electric machine, which has a maximum relative magnetic permeability in a direction . 5. The magnetic resistance according to claim 4 ,
The stator of the rotating electric machine, wherein the support member of the slot at the position of is made of a material having magnetic anisotropy and having a larger relative magnetic permeability than other support members.