KR101842827B1 - Double Stator Axial Field Type Switched Reluctance Motor - Google Patents

Abstract

The present invention relates to a dual stator axial field-type switched reluctance motor and, more specifically, to a dual stator axial field-type switched reluctance motor configured to uniformly and effectively maintain air gaps by arranging a rotor between double stators in an axial direction, and to improve torque generation efficiency by using a magnetic flux path in an axial direction. According to an embodiment of the present invention, the dual stator axial field-type switched reluctance motor comprises: a first stator having a plurality of first stator poles and a plurality of first stator auxiliary poles facing an axial direction; a second stator having a plurality of second stator poles and a plurality of second stator auxiliary poles symmetrically formed opposite to the first stator; and a rotor positioned between the first and second stators and having a plurality of rotator poles. In addition, each of the first and second stator poles is wound with coils, and a constant air gap is formed between the rotor and the first stator, and between the rotor and the second stator.

Description

[0001] The present invention relates to a double stator axial field type switched reluctance motor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-stator axial field type switched reluctance motor, and more particularly, to a double-stator field-type switched reluctance motor in which a rotor is disposed between double stator in an axial direction, To a dual-stator field-type switched reluctance motor.

A Switched Reluctance Motor (hereinafter referred to as SRM) rotates a rotor by using a reluctance torque according to a change in magnetic reluctance, There is little or no need for it, and reliability is high, and life is almost permanent.

The SRM is a double pole-type structure and is a single excitation type device.

Here, a winding is wound around a stator, and a rotor is formed of a simple structure without a winding by a laminated structure of a silicon steel plate. Compared to other types of motors, SRM has a low maintenance and durability, a solid structure, a permanent magnet, and a simple structure and a wide range of speed characteristics compared to other motors.

SRM also has outstanding features such as high reliability and low hysteresis loss. For this reason, SRM has received much attention in recent years and is being discussed as a good alternative in drive applications.

Therefore, the SRM is advantageous in that it is mechanically robust as shown in Fig. 1, is stable for high-speed operation, is inexpensive, and can operate at high temperature or intense temperature changes.

In other words, the SRM is a dual-pole-type structure, and there is a excitation winding only in the stator, and a simple structure motor without a winding or a magnet is used as a rotor. The motor can be manufactured at low cost, and is mechanically robust, to be.

As shown in FIG. 2, SRM is being studied in many fields such as an emer drill, a blower, a washing machine, an electric vehicle, and an aerospace industry.

In addition, the SRM can be used to drive a car cooling fan, as shown in FIG.

However, since the conventional SRM has a radial configuration in which the rotor is inserted in the stator, the stator and the rotor are disposed in order along the axial direction and the axial flux path is used to improve the torque generating efficiency. SRM configuration is required.

Korean Patent Registration No. 10-1255934 entitled " Lateral Switched Reluctance Motor "(Registered on April 11, 2013).

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described need, and it is an object of the present invention to provide a stator of a stator, which can arrange one segment rotor in the axial direction between two stator so as to efficiently maintain the gap constantly, The present invention relates to a dual-stator axial-field-type switched reluctance motor.

According to an aspect of the present invention, there is provided a double-stator field-type switched reluctance motor including a first stator having a plurality of first fixed magnetic poles and a first stator auxiliary pole oriented in an axial direction, A second stator having a plurality of second fixed magnetic poles symmetrically opposed to the first stator and a second stator auxiliary pole opposed to the first stator and a rotor having a plurality of rotating magnetic poles and disposed between the first stator and the second stator, .

Each of the first stationary magnetic pole and the second stationary magnetic pole is wound with a winding, and a constant air gap is formed between the rotor and the first stator, and between the rotor and the second stator.

According to the present invention, there are two stator (s) on both sides of the rotor, so that the stator attracts the rotor from both sides, thereby minimizing the pore change.

The stationary magnetic pole in which the winding is wound has a trapezoidal shape in which the tip? S1 is narrower than the base? S, which is advantageous in that it has a short magnetic flux path.

In addition, there is an advantage that the pole tooth angle? 1 of the rotating magnetic pole is made larger than the pole tooth angle? 1 of the fixed magnetic pole so that the starting torque efficiency can be increased.

1 is an exemplary diagram showing a switched reluctance motor (SRM).
2 is a diagram illustrating an example of a field to which a switched reluctance motor (SRM) is applied.
3 is an exemplary illustration of a switched reluctance motor (SRM) applied to the automotive field.
4 is a perspective view schematically illustrating a single stator transverse axis SRM.
5 is an exploded perspective view schematically illustrating a single stator transverse axis SRM.
6 is a schematic cross-sectional view showing a single stator transverse axis SRM.
FIG. 7 is an exemplary real image of a single stator transverse axis SRM.
8 is a cross-sectional view schematically showing a single stator transverse axis SRM.
9 is a schematic perspective view illustrating a dual stator axial field type switched reluctance motor according to an embodiment of the present invention.
10 is an exploded perspective view of Fig.
11 is a schematic perspective view showing the stator of Fig.
12 is a schematic perspective view showing the rotor of Fig.
13 is a schematic conceptual cross-sectional view illustrating a dual stator axial field type switched reluctance motor according to an embodiment of the present invention.
FIG. 14 is a torque comparison graph for a dual stator axial field type switched reluctance motor according to an embodiment of the present invention.
15 is a graph showing a comparison of inductance of a dual stator axial field type switched reluctance motor according to an embodiment of the present invention.
16 is a graph illustrating axial force comparison for a double stator axial field type switched reluctance motor according to an embodiment of the present invention.
17 is a view showing the sign of the stator of the transverse axis SRM.
18 shows a double stator slot code.
19 is a diagram showing a segmented rotor code.
20 is a magnetic flux density distribution diagram.
21 is a motor torque comparison graph.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

The embodiments of the present invention described with reference to the drawings specifically illustrate an ideal embodiment of the present invention. As a result, various variations of the illustration, for example variations in the manufacturing method and / or specification, are expected. Thus, the embodiment is not limited to any particular form of the depicted area, but includes modifications of the form, for example, by manufacture. The regions shown or described as being flat may have characteristics that are generally wavy / rough and nonlinear.

Also, the portion shown as having a sharp angle may be rounded. Thus, the regions shown in the figures are merely approximate, and their shapes are not intended to depict the exact shape of the regions, nor are they intended to limit the scope of the present invention.

The drawings are schematic and illustrate that they are not drawn to scale. The relative dimensions and ratios of the parts in the figures are shown exaggerated or reduced in size for clarity and convenience in the figures, and any dimensions are merely illustrative and not restrictive. And to the same structure, element, or component appearing in more than one of the figures, the same reference numerals are used to denote corresponding or similar features in other embodiments.

FIG. 4 is a perspective view schematically showing a single stator transverse axis SRM, FIG. 5 is an exploded perspective view schematically showing a single stator transverse axis SRM, FIG. 6 is a cross sectional schematic view showing a single stator transverse axis SRM, FIG. 8 is a cross-sectional view schematically showing a single stator transverse axis SRM. FIG.

The transverse axis SRM (Switched Reluctance Motor) proposed in the present invention uses an axial magnetic flux path unlike the conventional radial type, so that the torque generating efficiency is high. The rotor of the proposed motor consists of segments and the stator consists of stimulus and auxiliary stimulus. High output torque can be produced by stator of both sides, that is, upper and lower excitation system. In the present invention, the design parameter is selected to increase the average torque of the motor and compared with a single stator excitation method by simulation.

In the present invention, a dual stator axial field type switched reluctance motor 100 having two stators and one segment rotor is proposed, and characteristics of a single stator SRM are compared.

As shown in FIG. 4, the single stator transverse SRM includes a stator, a winding surrounding the stator, and a rotor spaced apart from the stator by a predetermined distance.

More specifically, as shown in FIG. 5, a single stator transverse axis SRM includes a stator having stator poles and stator auxiliary poles, and a rotor having a rotating magnetic pole spaced apart from the stator by a predetermined distance .

6 schematically shows a cross-section of a single stator transverse axis SRM in which a winding is wound around a stationary magnetic pole, and a rotor is located at a predetermined distance from the stator.

On the other hand, in the conventional stator transverse axis SRM, as shown in FIG. 6, the winding portions wound around the stationary magnetic poles have the same width at the top and bottom.

In addition, the single stator abscissa SRM has higher torque density, lower copper loss and iron loss than the basic 12/8 SRM.

However, as shown in FIG. 7, a single stator transverse axis SRM requires a high-priced bearing to maintain a constant gap, has difficulty in maintaining a torque, and has a problem that a short can easily occur.

That is, as shown in FIG. 8, when the single stator transverse axis SRM is driven, it is very difficult to keep the gap G constant since the left and right vibrations are easily generated between the stator and the rotor at the time of driving.

FIG. 9 is a schematic perspective view illustrating a double-stator axial field type switched reluctance motor according to an embodiment of the present invention, FIG. 10 is an exploded perspective view of FIG. 9, Fig. 12 is a schematic perspective view showing the rotor of Fig. 10; Fig.

13 is a schematic conceptual cross-sectional view illustrating a dual-stator axial field type switched reluctance motor according to an embodiment of the present invention. FIG. 14 is a cross-sectional view of a dual stator axial field type switched reluctance motor according to an embodiment of the present invention. 15 is a graph showing a comparison of inductance of a double-stator axial field type switched reluctance motor according to an embodiment of the present invention, and FIG. 16 is a graph showing the inductance of a dual stator field-type rotary reluctance motor according to an embodiment of the present invention. FIG. 5 is a graph showing an axial force comparison for a switched reluctance type motor.

Therefore, in order to overcome this disadvantage, as shown in Figs. 9 and 10, it is possible to have two stator (s) on both sides of the rotor so that the stator attracts the rotor from both sides, The present invention is proposed.

In particular, as shown in FIG. 11, the dual-stator axial field-type switched reluctance motor 100 proposed in the present invention has a winding portion wound on a stationary magnetic pole so as to be narrower than the lower portion to have a short magnetic flux path.

In addition, greater than the double stator Axial Field Type Switched Reluctance Motor 100 has a starting torque (Starting Torque) pole firing angle of the rotating magnetic pole to the Efficiency (δ ₁₎ pole firing angle of the fixed magnetic pole (θ ₁₎ proposed by the present invention .

In addition, the dual stator field-type switched reluctance motor 100 proposed in the present invention can generate a higher torque than the conventional 12/8 type or single stator transverse shaft type.

The dual-stator axial field type switched reluctance motor 100 proposed by the present invention will now be described in more detail.

As shown in FIG. 9, a double stator axial field type switched reluctance motor 100 according to an embodiment of the present invention includes a first stator 110, a rotor 120 And a second stator 130. The rotor 120 is positioned between the first stator 110 and the second stator 130 and the first stator 110, The electrons 120 and the second stator 130 are arranged so that it is possible to solve the problem that the torque is hardly maintained or the gap can not be kept constant.

Windings are wound around the first stator 110 and the second stator 130, respectively.

10, the first stator 110, the rotor 120, and the second stator 130 are coupled to a shaft (not shown) of the double-stator field-type switched reluctance motor 100 according to an embodiment of the present invention. The first stator 110 includes a plurality of first fixed magnetic poles 111 protruding in the axial direction and a first stator auxiliary pole 113 and the second stator 130 Is provided with a plurality of second fixed magnetic poles 131 and second stator auxiliary poles 133 opposed to the first stator 110. The rotors 120 are disposed between the first stator 110 and the second stator 110. [ A plurality of rotating magnetic poles 121 are disposed between the stator 130 and the first stationary magnetic poles 111 and the second stationary magnetic poles 131 are surrounded by windings. (For reference, FIG. 10 does not show the windings on the first stator 110 in the drawing so that the shape of the stator can be easily understood.)

11, the first stator 110 proposed in the present invention includes a first fixed magnetic pole 111 and a first stator auxiliary pole 113, and the fixed magnetic pole is fixed to the main pole The polar angle of the excitation (θ ₁ ) is greater than the polar angle of the stator auxiliary pole (θ ₂ ).

11, X denotes the distance between the stator poles and the stator coils.

The stator proposed in the present invention has a trapezoidal shape in which a winding is wound on a stationary magnetic pole and a tip (β _s1 ) is formed narrower than a base (β _s ) And increases the torque generation efficiency.

The second stator 130 has the same configuration as that of the first stator 110.

12, the rotor 120 proposed by the present invention has a plurality of rotating magnetic poles 121 and is connected to a non-magnetic member such as aluminum for fixing the rotating magnetic poles 121. As shown in FIG.

12,? ₁ denotes a polar angle of the rotating magnetic pole, R1 denotes the inner diameter of the rotating magnetic pole, R2 denotes the outer diameter of the rotating magnetic pole, and Y denotes the interval between the rotating magnetic poles.

<Motor Dimensions> Parameter One Stator
12-10 SRM Double Stator
12-10 SRM Number of Phase 3 3 Outer Radius (mm) 52 52 Stack length (mm) 35 35 Air gap (mm) 0.25 0.25 Stator pole arc (°) 32 36.5 / 23.5 Rotor pole arc (°) 31 38 Turn number Phase 10 5 × 2 Slot fill factor (%) 0.3 0.3

Table 1 shows the design dimensions and the dimensions of a single stator SRM for a dual-stator axial field type switched reluctance motor proposed in the present invention.

Design dimensions of the double stator Axial Field type switched reluctance motor in accordance with an embodiment of the invention is a pole firing angle (θ ₁₎ of the fixed magnetic pole is 36.5 ° and the pole firing angle of the stator auxiliary pole (θ ₂₎ as shown in Table 1 above. 23.5, and the polar angle? ₁ of the rotating magnetic pole is 38 °.

FIG. 13 is a schematic cross-sectional view illustrating a dual-stator axial field type switched reluctance motor 100 according to an embodiment of the present invention. In the SRM 100 proposed in the present invention, tip ( _s1 ) is formed in a trapezoidal shape that is narrower than the base ( _s ) to have a short magnetic flux path and increase the torque generation efficiency.

FIG. 14 is a torque comparison graph for a double stator axial field type switched reluctance motor 100 according to an embodiment of the present invention. The double stator axial field type switched reluctance motor (red line) The torque ripple is small by maintaining a gentler curve than the stator horizontal axis SRM (blue dotted line).

FIG. 15 is a graph showing the inductance of a dual-stator axial field type switched reluctance motor according to an embodiment of the present invention. The double stator axial field type switched reluctance motor (red line) proposed in the present invention is a single stator transverse axis SRM (Blue dotted line), so that a stable torque can be formed.

FIG. 16 is a graph showing an axial force comparison for a dual-stator axial field type switched reluctance motor according to an embodiment of the present invention. The dual-stator axial field type switched reluctance motor (red line) The axial force can be kept almost zero so that the gap between the rotor and the stator can be kept constant.

On the other hand, the single stator abscissa SRM (blue line) is unstable due to the axial force, and the air gap between the rotor and the stator can not be maintained constant.

Therefore, the dual-stator axial field type switched reluctance motor 100 according to an embodiment of the present invention includes a first fixed magnetic pole 111 and a first stator auxiliary pole 113, A second stator 130 having a plurality of second fixed magnetic poles 131 and second stator auxiliary poles 133 formed symmetrically opposite to the first stator 110; And a rotor 120 disposed between the first stator 110 and the second stator 130 and having a plurality of rotating magnetic poles 121.

Each of the first stationary magnetic poles 111 and the second stationary magnetic poles 131 is wound by a winding and is disposed between the rotor 120 and the first stator 110, between the rotor 120 and the second stator 130, A constant air gap is formed.

13, each of the first fixed magnetic poles 111 and the second fixed magnetic poles 131 has a trapezoidal shape after a predetermined depth end thereof is formed, and a tip thereof is formed to be narrower than a base The winding is wound.

The first stator 110 includes six first fixed magnetic poles 111 and six first stator auxiliary poles 113. The second stator 130 includes six second fixed magnetic poles 131, Six second stator auxiliary poles 133 are constituted, and the rotor 120 is constituted by ten rotating magnetic poles 121.

Further, the first pole firing angle (θ ₁₎ of the fixed magnetic pole 111 pole firing angle (θ ₁₎ is a first stator auxiliary pole 113 pole firing angle (θ ₂₎ greater than the second fixed magnetic pole (131) of the second pole firing angle of the stator auxiliary pole 133 pole whistle, the rotational magnetic pole (121) greater than (θ ₂₎ (δ ₁₎ is the first pole firing angle of the fixed magnetic pole (111) (θ ₁₎ or the second Is formed to be larger than the polar angle? ₁ of the fixed magnetic pole 131.

The dual-stator axial field type switched reluctance motor according to one embodiment of the present invention is an improved invention based on the research data published by the present inventor in July, The data are as follows.

FIG. 17 is a diagram showing the stator of a transverse axis SRM, FIG. 18 is a diagram showing a double stator slot code, FIG. 19 is a diagram showing a segmented rotor code, FIG. 20 is a magnetic flux density distribution diagram, 21 is a motor torque comparison graph.

1. Dual stator design

Figure 17 defines the design dimensions of the transverse axis SRM. D ₁ is the outer diameter, and _Di is the inner diameter. The inner diameter and outer diameter of the double stator transverse SRM and single stator transverse SRM are similar.

However, the stator height of the double stator transverse SRM is half the stator height of the single stator transverse SRM. For example, if the stator height of a single stator transverse SRM is 30 mm, the stator height of the double stator transverse SRM is 15 mm.

We describe the mathematical model of the proposed structure based on the previous studies such as the pole-arc coefficient of the transverse axis SRM, the yoke thickness of the stator rotor pole, and the choice of pole number.

In equations (1) and (2), D _av is the average length of the core and L _a is the thickness of the core.

(1)D _av =

(One)

(2)L _a =

(2)

Apparent power (KVA) is as follows.

_{Sc = m · E a · I} a · 10 - 3 (3)

m is the armature winding current, E _a is the total load phase electromotive force I _a is the phase current.

_{E a = 2 · K B ·} f · N φ · K dp · Φ = 2 · α δ · K a · (pn / 60) · N φ · B δ · τ av · L a (4)

)·B_δ (5)陸 = 留_隆 · τ _av · L _a · B _δ = (π / 8p) · α _δ · (

) &_Amp;_bull; (5)

이다.K _av is the duty cycle, K _dp is the application application constant, α _δ is the pore air density, K _a is the air gap density, _{δ av} is the average distance of the pole, B _δ is the vacancy flux density, K _B is the duty cycle,

to be.

E _a can be redefined as follows.

) (6) _{E a = 2 · α δ ·} K a · (pn / 60) · N φ · B δ · (π / 8p) · τ av · (

) (6)

And the armature current is calculated as follows.

(7)I =

(7)

Apparent power (KVA) is recalculated as follows.

(8)S _c =

(8)

Since the winding of the slot is defined, the winding of the load is related to the diameter. Since the maximum inner diameter A = A _min , the power of the inner and outer line loads using A _av and A _max can be defined as:

(9)S _c =

(9)

=1.732를 얻을 수 있다.Equation (9) to obtain the A _max, B _δ, D ₁ to D _i induce to obtain the S _c. The ratio of the outer diameter to the inner diameter is as follows. k = D ₁ / D _i =

= 1.732.

If the value of k is taken as a large value, the inner diameter D _i will be small and the load will be high.

Further, the temperature of the motor becomes high, and it becomes difficult to correct the end of the coil. The most suitable ratio of k has a value of 1.732, at which time the apparent power is most suitable.

2. Dual stator slot design

The inner diameter and outer diameter of the stator were determined by the above equation. The stator slot is designed considering flux path and magnetic flux density. Also, the slot should be set considering the fill factor (30 mm ² ). The stator slot determines the length of the pole, and the length of the pole affects the drive of the motor.

Referring to Figure 18, the distance X between the stator poles should be the same as the distance Y between the segmented rotors. At this time, when X, Y becomes larger, the size of the segment rotor β _r becomes smaller.

As the size of the segmented rotor decreases, the flux path of the stator and the rotor becomes smaller. Also, when the value of X and Y becomes large, the shape of the same segment rotor will not be exactly the shape of the tenth. The width in the slot (S _cs + L _s ) × ω _sb should always be designed considering the same area. In addition, the magnetic flux density should be designed to be smaller than 1.8 [T].

S _cs + L _s is defined as 15 mm considering the length of the entire stack. And L _s and the segment rotor thickness are equal to each other to make the magnetic flux transfer the same in both sections.

3. Segmented rotor

The segmented rotor has an aluminum rotor that holds the segmented rotor with ten segmented rotors as shown in FIG.

19 is a segmented rotor made in accordance with the formation of a stator slot pole. The distance between each segment rotor Y is equal to the distance of stator slot X. This eliminates unnecessary transmission when the stator and rotor are in an unaligned position. At this time, β _r must be modified according to the value of Y.

<Design Parametes> Parameter Conventional
12/8 SRM One Stator
12-10 SRM Double Stator
12-10 SRM Number of Phase 3 3 3 Outer Radius (mm) 52 52 52 Outer Radius of Rotor (mm) 31 52 52 Inner radius of rotor (mm) 24 32 32 Length of stack
(mm) 35 35 35 Length of air gap
(mm) 0.25 0.25 0.25 Number of turns 10 10 10 Stator pole arc
(°) 14 32 36.5 Rotor pole arc
(°) 16 31 38

Table 2 shows the designed dimensions and the dimensions of the existing motors. Each motor has three phases and a gap of 0.25.

4. Proposed motor characteristics

20 shows magnetic flux density distribution at the alignment position when the maximum magnetic flux density is 1.8 [T]. 20, it can be seen that the magnetic flux density is lower than 1.8 [T].

One cycle of one phase is 36 °, and the constant torque portion in Fig. 14 is 0 ° to 18 °.

Fig. 21 shows the torque characteristic comparison results of the three types of motors. In this case, the average torque in the order of double stator, single stator, and 12/8 SRM is 1.4 [N.m], 1.3 [N.m] and 1.2 [N.m], respectively.

Therefore, in the present invention, a double stator is proposed to secure the disadvantages of a single stator. We simulated a segmented rotor and a double stator and compared torque and magnetic flux density. The transverse axis SRM has a shorter flux path and a larger area of the segmented rotor than the conventional radial 12/8 SRM, resulting in more torque and lower core loss and copper loss. Simulation results show that the designed dual stator abscissa SRM increased 20% average torque and 12% more than 12/8 SRM and 10% more than single axle SRM. The double stator was designed to keep the gap constant.

As described above, the double stator axial field type SRM 100 according to the embodiment of the present invention can expect the following effects.

There are two stator (s) on either side of the rotor, which allows the stator to attract the rotor from both sides, minimizing pore changes.

The stationary magnetic pole in which the winding is wound has a trapezoidal shape in which the tip? S1 is narrower than the base? S, which is advantageous in that it has a short magnetic flux path.

In addition, there is an advantage that the pole tooth angle? 1 of the rotating magnetic pole is made larger than the pole tooth angle? 1 of the fixed magnetic pole so that the starting torque efficiency can be increased.

It will be apparent to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the essential characteristics of the invention. will be.

Therefore, the embodiments disclosed in the present invention and the accompanying drawings are intended to illustrate and not to limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings .

The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: Dual stator axial field type switched reluctance motor proposed by the present invention
110: first stator
120: rotor
130: second stator

Claims (4)

A first stator having a plurality of first fixed magnetic poles oriented in the axial direction and a first stator auxiliary pole,
A second stator having a plurality of second fixed magnetic poles and second stator auxiliary poles symmetrically opposed to the first stator,
And a rotor disposed between the first stator and the second stator and having a plurality of rotating magnetic poles,
Each of the first fixed magnetic pole and the second fixed magnetic pole is wound with a winding,
A constant air gap is formed between the rotor and the first stator and between the rotor and the second stator,
Wherein the first stationary magnetic pole has a trapezoidal shape after a predetermined depth end thereof is formed, and an upper portion of the first stationary magnetic pole is narrower than a lower portion thereof,
Wherein the second stationary magnetic pole has a trapezoidal shape after a predetermined depth of a cross section thereof is formed, and an upper portion of the second stationary magnetic pole is narrower than a lower portion of the second stationary magnetic pole so that the coil is wound. delete The method according to claim 1,
Wherein the first stator comprises six first fixed magnetic poles and six first stator auxiliary poles,
The second stator comprises six (6) second fixed magnetic poles and six (6) second stator auxiliary poles,
Wherein the rotor comprises ten rotating magnetic poles. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
Wherein a polar angle of the first fixed magnetic pole is larger than a polar angle of the first stator auxiliary pole,
Wherein a polar angle of the second fixed magnetic pole is greater than a polar angle of the second stator auxiliary pole,
Wherein the pole tip angle of the rotating magnetic pole is formed to be larger than the pole tip angle of the first stationary magnetic pole or the pole tip angle of the second stationary magnetic pole.

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