KR101265825B1 - Dual stator rfpm(radial flux permanent magnet) generator - Google Patents

Abstract

PURPOSE: A double stator RFPM(Radial Flux Permanent Magnet) generator is provided to generate different reluctance for each slot, thereby improving output and efficiency of the RFOM generator. CONSTITUTION: Coils(120,220) are wound in multiple slots. Magnetic flux is generated in permanent magnets(400). An inner stator(100) and an outer stator(200) form a closed circuit of a rotor(500). The rotor is positioned between the inner stator and the outer stator. The rotor acts as a cooling fan in generating power.

Description

Dual Stator RPM generator {Dual Stator Radial Flux Permanent Magnet (RFPM) generator}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for reducing cogging torque of a wind generator, and more particularly, to a dual stator RFPM generator capable of effectively reducing cogging torque through positional transition between dual stators.

Axial Flux Permanent Magnet (AFPM) Generator and Radial Radiator to Eliminate Cogging Torque that Reduces Efficiency and Power by Degrading Cut-in-Speed Attention has been focused on the development of Radial Flux Permanent Magnet (RFPM) generators.

AFPM generator is a generator that is widely used in small and hybrid wind generators. It is common to place permanent magnets on both sides and coils in the center. Coreless AFPM does not use iron core to minimize cogging torque. Most of the generators. Because it is coreless, the initial starting wind speed is low and the output is high at the rated wind speed, but the power and efficiency of the generator itself are inferior and the manufacturing cost is high. In addition, the actual output is very low at 5 ~ 7m / s compared to commercial wind speed has a disadvantage that can not be applied to large wind generators.

RFPM generator is a generator with the same structure as a permanent magnet motor. It has a disadvantage of high starting wind speed due to high cogging torque. However, it is not only used for low production cost and capacity, but also has high output and efficiency. have. In addition, it is suitable for hybrid streetlights because it can output more than 20% of rated power even at 5 ~ 7m / s, which is a commercial wind speed.

Meanwhile, a coreless AFPM generator patent technology (for example, Republic of Korea Patent Publication No. 10-0870738) has been developed and used as a small wind generator.

However, since the coreless AFPM generator has no cogging torque but no core as described above, there are various disadvantages such as output reduction, efficiency reduction, cost increase, and the like which cannot be applied to a large wind generator.

Therefore, the present invention provides a small size with a "slot," which makes it possible to obtain a higher power generation efficiency and output voltage than a conventional coreless AFPM generator, which has been patented (10-2011-0085567) and proposed by the applicant. Following the technical development of the longitudinal axis permanent magnet synchronous generator for wind power generators, we propose a new dual stator RFPM generator that reduces cogging torque through stator position transfer.

An object of the present invention is to improve the problems of the prior art, and more specifically, in the stator shape of the dual stator (slot with a slot) rotated form, different changes in reluctance for each slot The dual stator RFPM generator is designed to reduce the cogging torque generated from the RFPM generator by obtaining a constant electrical angle so as to generate a high electrical efficiency and output voltage. to provide.

According to a feature of the present invention for achieving the above object, in the Radial Flux Permanent Magnet (RFPM) generator, the RFPM generator, the coil (120, 220) is wound in a plurality of slots (110, 210), It has an inner stator (Inner Stator, 100) and an outer stator (Outer Stator, 200) to bridge the magnetic flux generated in the permanent magnet 400 so that the rotor 500 can form a closed circuit in one independent magnetic field, A dual stator (300) in which the stator displacement is performed by shifting the outer stator to a constant electric angle relative to the inner stator to reduce cogging torque between the inner stator and the outer stator; The magnetic flux of the permanent magnet is interlinked to the outer stator 200 by forming a closed circuit in an independent magnetic field for the permanent magnet installed and arranged on the upper part of the rotor 500, and at the same time, arranged at the lower part of the rotor 500. A plurality of permanent magnets (Permanent Magnet, 400) for releasing the magnetic flux of the permanent magnet to the inner stator 100 by forming a closed circuit in one magnetic field for the installed permanent magnet; The plurality of permanent magnets positioned between the inner stator 100 and the outer stator 200 to have a shape of a circular ring (510), having the same polarity on the outside and the inside of the circular ring (510). 400 is provided with a dual stator RFPM generator, characterized in that consisting of a rotor (Rotor, 500) is arranged in sequence at regular intervals and attached to the role of the cooling fan (Fan) during power generation.

According to an embodiment of the present invention, the stator displacement may include 25 to 35 [deg. (E)] (the optimal transition angle) of the outer stator 200 at an electrical angle relative to the inner stator 100. 30 [deg. (E)]), but obtained by the following formula.

는,Number of Cogging Torques Generated per Rotation in Internal and External Stator

Quot;

이고

ego

At this time, the machine angle for generating the cogging torque once,

이며,

Is,

를 전기각으로 표현한

는,top

In terms of electrical angle

Quot;

이다.

to be.

When the outer stator is transferred and the cogging torque generation phase is shifted to 180 [deg. (E)], the cogging torque generated at this time is represented by a sum.

이다.

to be.

Therefore, the stator position transition angle that shifts the cogging torque phase occurring at the outer stator to 180 [deg. (E)],

here

.

The dual stator RFPM generator of the present invention has the following effects.

According to the present invention, a dual stator RFPM generator for which a slotted dual stator transfers a stator position by giving a constant electric angle so that different reluctance changes occur in each slot in a stator shape of a rotated form. By implementing

The cogging torque generated from the inner stator and the outer stator and the cogging torque generated from the inside of the generator cancel each other to minimize cogging torque when starting the generator, as well as the cooling characteristics of the armature winding by the rotor as a cooling fan. This is excellent, there is an effect that can increase the output and efficiency of the generator.

1 is a view schematically showing the overall configuration of a dual stator RFPM generator according to a preferred embodiment of the present invention
2 is a view showing the shape of the inner stator of FIG.
3 is a view showing the shape of the outer stator of FIG.
4 is a view showing the shape of the permanent magnet and the rotor of FIG.
5 is a view showing a state before the stator position transition for a double stator having an inner stator and an outer stator according to a preferred embodiment of the present invention;
6 is a view showing a state after the stator position transition for the double stator having an inner stator and an outer stator according to a preferred embodiment of the present invention;
7 is a view showing a stator position shifting method for a double stator having an inner stator and an outer stator according to a preferred embodiment of the present invention.
8 and 9 are diagrams illustrating an analysis result of FIG. 7.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. The prior art should be interpreted as such. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

First, cogging torque is non-uniform torque in a generator or motor. It is a force in the folding direction that tries to move to the position where the magnetic energy of the generator system is minimum. The rotor permanent magnet and the stator teeth are independent of the load current. This is due to a change in reluctance with respect to the circumferential direction caused by the interaction of the slot (Stator teeth, Slot) structure. In other words, when you grab the shaft of a generator (or motor) and turn it slowly, it doesn't turn smoothly, but it doesn't turn smoothly, but it rotates unevenly. The difference between the big and the smallest. This large cogging leads to greater torque ripple when driving the generator, making it difficult to control the generator.

Most of these techniques to reduce cogging torque have been optimized for skewed permanent magnet design, slot deformation design, magnet machining, number of poles and slot number.

However, in the exemplary embodiment of the present invention, different slots have different reluctance for each slot in a stator shape in which a dual stator having an inner stator having an slot and an outer stator is rotated. By changing the position between the inner and outer stators by giving a constant electric angle so that a change occurs, the cogging torque for the output start point wind speed (Cut-in-Speed) is reduced, so that the generator can be operated at a low wind speed of 3 to 5 m / s. It is characterized by the implementation of a dual stator RFPM generator, which makes it possible to greatly increase the power and efficiency.

1 to 9, the core technical constituent means of the dual stator RFPM generator according to the preferred embodiment of the present invention, a double having an inner stator (Inner Stator, 100) and an outer stator (Outer Stator, 200) It consists of a stator 300, a permanent magnet (400), a rotor (Rotor, 500).

Here, the dual stator RFPM generator according to an embodiment of the present invention is fixed to a rotor connected to a blade receiving a wind, which is a power generator of a wind generator, and rotates by mechanical power generated as the rotor rotates. To rotate the rotor 500. In addition, the inner stator 100 and the outer stator 200 are located outside and inside of the circular ring 510 of the rotor 500 are coupled to each of the upper and lower housings (not shown) of the wind generator This is obvious in the field of wind generator technology.

Referring to FIGS. 1 and 2, the inner stator 100 windings coils 120 in a plurality of slots 110 and serves as a magnetic path for magnetic flux generated in the permanent magnet 400. As a means, the permanent magnet 400 is installed inside the rotor 500 is attached, the coil 120 is wound around the plurality of slots 110 formed in the inner stator 100 with a constant number of turns have. The plurality of slots 110 in which coils are wound are formed on the outer circumferential surface of the inner stator 100.

That is, the magnetic flux of the permanent magnet 400 is bridged to the inner stator 100 in which the coils 120 are wound in the plurality of slots 110 so that the rotor 500 can form a closed circuit in one independent magnetic field. do.

Referring to FIGS. 1 and 3, the outer stator 200 windings coils 220 in a plurality of slots 210 and serves as a magnetic path of magnetic flux generated in the permanent magnet 400. As a means, the permanent magnet 400 is installed on top of the rotor 500 is attached, the coil 220 is wound around the plurality of slots 210 formed in the outer stator 200 with a constant number of turns have. The plurality of slots 210 wound around the coil are formed on the inner circumferential surface of the outer stator 200.

That is, by rotating the magnetic flux of the permanent magnet 400 to the outer stator 200, the coil 220 is wound in a plurality of slots 210 so that the rotor 500 can form a closed circuit in one independent magnetic field do.

In addition, the inner stator 100 and the outer stator 200 are designed such that the length of the inner stator 100 slot 110 is larger than the length of the outer stator 200 slot 210. The reason is that the inner stator slot is smaller than the outer stator, so if the same slot length is designed, the number of coil windings wound on the inner stator becomes smaller and the inner output is smaller than the outer stator. This is to make the same output by designing bigger than the length.

Here, with reference to FIGS. 5 to 9, the stator displacement of the dual stator 300 having the inner stator 100 and the outer stator 200 according to the embodiment of the present invention is further described. It demonstrates in detail.

Stator Displacement according to an embodiment of the present invention, the outer stator 200 in the electric angle compared to the inner stator 100 25 ~ 35 [deg. (E)] (optimum transition angle: 30 [deg. (e)]), but obtained by the following formula.

In other words,

는 다음과 같이 나타낼 수 있다.Number of Cogging Torques Generated per Rotation in Internal and External Stators

Can be expressed as follows.

(1)

(One)

Therefore, the mechanical angle for generating the cogging torque once can be expressed as follows.

(2)

(2)

를 전기각으로 표현한

는

In terms of electrical angle

The

(3)

(3)

.

Here, deg. (E) of Equation (3) means the electric angle, which means that the two poles of N and S of the rotor bridge the stator values irrespective of the number of rotor poles. )] Is a standard.

On the other hand, the cogging torque is represented by the sum of the cogging torque by the inner stator 100 and the cogging torque by the outer stator 200, to reduce the cogging torque generated in each of the inner and outer stator according to an embodiment of the present invention In the stator position shifting method, the cogging torque generation phase generated in the outer stator through the positional shift of the outer stator 200 is transferred as shown in Equation (4) below, and the sum of the cogging torques generated in the inner and outer stator is 0. To make it Zero. That is, when the outer stator 200 is shifted in position and the cogging torque generation phase is shifted to 180 [deg. (E)], the generated cogging torque can be made zero.

(4)

(4)

Therefore, the stator position transition angle for transferring the cogging torque phase generated at the outer stator 200 to 180 [deg. (E)] can be expressed by Equation 5 below.

(5)

(5)

here

to be.

는 코깅토크가 한번 발생하는 전기각을 나타내는 함수로써,

가 절반으로 될 때 코깅토크는 전기각으로 180[deg.(e)]의 위상을 가짐으로 외측 고정자(200)를 전이각 만큼 전이 시켰을 때 내ㆍ외측 고정자에서 발생하는 코깅토크 위상이 서로 반대가 되어 코깅토크가 상쇄되며 그에 따라 발전기의 코깅토크가 감소됨을 알 수 있다.As such, the equation (3)

Is a function representing the electric angle at which cogging torque occurs once.

The cogging torque has a phase of 180 [deg. (E)] when the electric angle is half, so when the outer stator 200 is shifted by the transition angle, the cogging torque phases generated in the inner and outer stators are opposite to each other. It can be seen that the cogging torque is offset so that the cogging torque of the generator is reduced accordingly.

Referring to FIGS. 8 and 9, based on the above equation, as a result of RFPM generator analysis of 20 poles and 30 slots, the outer stator 200 has an electric angle of 25 to 35 [deg. (E) compared with the inner stator 100. ] (Optimal transition angle: 30 [deg. (E)]) It was found that the smallest cogging torque occurred at the positional transition.

That is, since the coils 120 and 220 are constantly wound in the plurality of slots 110 and 210 formed in each of the inner and outer stators 100 and 200, the outer stator 200 may reduce the cogging torque and increase the output of the generator. It should be positioned at a constant electric angle compared to the inner stator 100.

The reason for this is to transfer the outer stator 200 by 25 to 35 [deg. (E)] (optimum transition angle: 30 [deg. (E)]) to the electric angle, which occurs in the outer stator 200. This is because cogging torque generated from the cogging torque and the inner stator 100 are opposite to each other, and cogging torque generated opposite to each other in the generator causes offsetting so that cogging torque can be minimized during initial startup of the generator.

In other words, the permanent magnet 400 attached to the rotor 500 is a magnet of rare earth metals, so the magnetic flux density is very high, so when the cogging torque is increased, a large starting torque is required at the start of the wind generator at low wind speeds. Start-up becomes impossible, and the efficiency and output characteristics of the wind generator are also reduced. Therefore, in the present invention, the stator position transition that the outer stator 200 twists 25 to 35 [deg. (E)] (optimum transition angle: 30 [deg. (E)]) at an electric angle compared to the inner stator 100 ( Stator Displacement) minimizes cogging torque to increase the efficiency and output characteristics of wind power generators, as well as facilitate the initial startup of wind power generators at low wind speeds (or breezes) of 3 to 5 m / s. to be.

Here, the electrical angle refers to a conversion of a mechanical angle generated when the rotor of the permanent magnet of the generator rotates to an electrical angle.

On the other hand, referring to Figure 9, after applying the stator displacement (Stator Displacement) according to an embodiment of the present invention, the cogging torque should be completely removed to a value of zero (Zero) according to the theoretical equation, the prototype In the actual analysis results, it was confirmed that a little cogging torque is generated differently from the theory, not the zero value in which cogging torque is completely removed due to the influence of leakage flux and harmonics.

As described above in the technical problem of the present invention, the slotted dual stator rotates with a constant electric angle such that a change in reluctance is generated for each slot in a stator shape in which the slotted dual stator is rotated. By changing the position of the stator by giving an electrical angle, it is confirmed that the cogging torque generated by the RFPM generator can be reduced.

1 to 6, the double stator 300 having the inner stator 100 and the outer stator 200 according to an exemplary embodiment of the present invention has 20 poles for cogging torque and output generation having the same size. It is necessary to adjust the shape of the 30 slots 110 and 210 and the number of coils 120 and 220 wound around the slots 110 and 210.

For example, the number of turns of the generator coil can be wound to the inner 94 turns and the outer 83 turns. Since the stator tooth design is designed at an angle rather than a length, the area of the outer stator is larger than that of the inner stator and the permanent magnet is also made larger.

In other words, the inner and outer stator teeth are designed at 9 [deg. (E)] angles and the permanent magnets are also designed at the same angle. This is to allow cogging torque to be generated at the same position when the rotor rotates. That is, because the stator teeth are designed at an angle rather than the stator tooth design, the outer stator teeth are larger than the inner stator teeth and receive more magnetic flux. Therefore, the number of turns of the inner coil of the generator is 94 turns and the number of turns of the outer coil is 83 turns. At this time, the coil spot ratio is designed to be 53.46 [%] inside and 53.17 [%] outside so that a similar output can be generated.

Referring to FIG. 4 again, the permanent magnet 400 is a magnet having a high magnetic flux density of rare earth metal type, and the inner stator 100 and the outer stator 200 having coils wound around the plurality of slots 110 and 210. In order to bridge the magnetic flux of the permanent magnets, magnets of the north pole and the south pole are arranged on the outside and inside of the rotor 500, and the outside and inside of the rotor form a closed circuit in one magnetic field. A plurality of permanent magnets (400) having the same polarity are arranged in a sequence of N polarity → S polarity → N polarity → S polarity or S polarity → N polarity → S polarity → N polarity at regular intervals. .

At this time, the magnetic flux chained to the inner stator 100 and the outer stator 200, the outer stator 200 from the N pole to the S pole or the S pole to the N pole of the permanent magnet arranged and arranged on the top of the rotor 500 The magnetic flux of the permanent magnet to the inner stator 100 via the N pole to the S pole or the S pole to the N pole of the permanent magnet installed at the bottom of the rotor 500 at the same time. Chains

In other words, the magnetic flux that is chained to the inner stator 100 and the outer stator 200 is one independent of the N pole to the S pole or the S pole to the N pole of the permanent magnet arranged and arranged on the upper part of the rotor 500. The magnetic flux of the permanent magnet is connected to the outer stator 200 by a closed circuit in the magnetic field, and at the same time, the N pole to the S pole or the S pole to the N pole of the permanent magnet installed and arranged below the rotor 500. The magnetic field of the magnetic field is made to bridge the magnetic flux of the permanent magnet to the inner stator (100).

And the plurality of permanent magnets 400 according to an embodiment of the present invention with reference to Figure 5 is made of a square, the coil (120, 220) in each of the slots (110, 210) of the inner stator 100 and the outer stator (200) Fabricate slightly larger than the wound cross section. This is to reduce the smooth flux linkage and cogging torque.

Also, referring to FIG. 4, the rotor 500 is a rotor means positioned between the inner stator 100 and the outer stator 200 and having a shape of a circular ring 510. A plurality of permanent magnets 400 having a predetermined size, but having the same polarity on the outside and the inside of the circular ring 510 at regular intervals, N polarity → S polarity → N polarity → S polarity or S polarity → N polarity → They are arranged in order from S polarity to N polarity and are attached.

In addition, the rotor 500 is a circular ring 510 to which the permanent magnet 400 is attached is located between the inner stator 100 and the outer stator 200, and the inner stator 100 and the outer stator Each of the slots 110 and 210 of the 200 is wound with a constant number of coils (or windings 120 and 220).

Here, in the case of a general AFPM generator or RFPM generator, there is a structure in which the permanent magnet is located outside and the stator winding is located inside, and the permanent magnet is located inside, and the stator winding is located outside. When the permanent magnet is located on the outside, the magnetic flux utilization rate is high due to the short pore length through which the magnetic flux of the permanent magnet passes, while the armature winding that generates a lot of heat is located inside the generator, which is somewhat disadvantageous in thermal cooling characteristics.

Therefore, in the embodiment of the present invention, in order to solve such a problem, the rotor 500 is disposed between the inner stator 100 and the outer stator 200 to which the permanent magnet 400 is arranged and attached to the circular ring 510 is located. Since the armature windings (or the outer and inner stator windings) are located outside the rotor 500, the rotor 500 acts as a fan during power generation. This has an advantageous effect in terms of output voltage gain.

2 to 9, the operation of the dual stator RFPM generator according to the preferred embodiment of the present invention will be described.

In the dual stator RFPM generator according to the embodiment of the present invention, the coils 120 and 220 are wound in a plurality of slots 110 and 210, and the rotor 500 is one independent magnetic field by intersecting magnetic flux generated from the permanent magnet 400. A dual stator (300) having an inner stator (100) and an outer stator (200) for achieving an intestinal closed loop, and capable of mutual stator displacement; The magnetic flux of the permanent magnet is interlinked to the outer stator 200 by forming a closed circuit in an independent magnetic field for the permanent magnet installed and arranged on the upper part of the rotor 500, and at the same time, arranged at the lower part of the rotor 500. A plurality of permanent magnets (Permanent Magnet, 400) for releasing the magnetic flux of the permanent magnet to the inner stator 100 by forming a closed circuit in one magnetic field for the installed permanent magnet; The plurality of permanent magnets positioned between the inner stator 100 and the outer stator 200 to have a shape of a circular ring (510), having the same polarity on the outside and the inside of the circular ring (510). By constructing a dual stator RFPM generator, characterized in that 400 is configured to be sequentially arranged at a predetermined interval and attached to the rotor (Rotor, 500) that serves as a cooling fan (Fan) during power generation, in the RFPM generator Cogging torques and generators generated in the inner stator and the outer stator by stator displacement with respect to the dual stator 300 having the inner stator 100 and the outer stator 200 are problematic. The cogging torques generated internally cancel each other, minimizing cogging torque when starting the generator, and the rotor's role as a cooling fan provides excellent cooling characteristics of the armature winding. There is an effect that can increase the rate.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: inner stator 110, 210: a plurality of slots
120, 220: coil
200: outer stator
300: Dual Stator
400: multiple permanent magnets
500: Rotor 510: Round Ring

Claims (6)

In Radial Flux Permanent Magnet (RFPM) Generator,
In the RFPM generator, coils 120 and 220 are wound around a plurality of slots 110 and 210, and the inside of the rotor 500 may form a closed circuit in one independent magnetic field by linking magnetic flux generated in the permanent magnet 400. The stator (Inner Stator, 100) and the outer stator (Outer Stator, 200), the outer stator in order to reduce the cogging torque between the inner stator and the outer stator, the stator position is shifted to a constant electric angle compared to the inner stator A dual stator 300 in which a stator displacement is made;
The magnetic flux of the permanent magnet is interlinked to the outer stator 200 by forming a closed circuit in an independent magnetic field for the permanent magnet installed and arranged on the upper part of the rotor 500, and at the same time, arranged at the lower part of the rotor 500. A plurality of permanent magnets (Permanent Magnet, 400) for releasing the magnetic flux of the permanent magnet to the inner stator 100 by forming a closed circuit in one magnetic field for the installed permanent magnet;
The plurality of permanent magnets positioned between the inner stator 100 and the outer stator 200 to have a shape of a circular ring (510), having the same polarity on the outside and the inside of the circular ring (510). Dual stator RFPM generator, characterized in that consisting of a rotor (Rotor, 500) 400 is attached to be arranged sequentially at a predetermined interval and acts as a cooling fan (Fan) during power generation
delete delete delete delete The method according to claim 1,
Stator Displacement, the outer stator 200 is 25 ~ 35 [deg. (E)] electric angle compared to the inner stator 100 (optimal transition angle: 30 [deg. (E)] ), But obtained by the following formula.
Number of Cogging Torques Generated per Rotation in Internal and External Stator

Quot;

ego
At this time, the machine angle for generating the cogging torque once,

Is,
top

In terms of electrical angle

Quot;

to be.
When the outer stator is transferred and the cogging torque generation phase is shifted to 180 [deg. (E)], the cogging torque generated at this time is represented by a sum.

to be.
Therefore, the stator position transition angle that shifts the cogging torque phase occurring at the outer stator to 180 [deg. (E)],

here

Dual stator RFPM generator, characterized in that

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