阅读说明：本技术 一种双余弦气隙磁通切换伺服电机 (Double cosine air gap flux switching servo motor ) 是由 花为 王培欣 章恒亮 程明 丁石川 于 2021-01-29 设计创作，主要内容包括：本发明提出了一种双余弦气隙磁通切换伺服电机,包括转子以及设置在转子外部的定子,定子与转子之间留有气隙,气隙的转子侧边界、定子侧边界均呈余弦曲线状。本发明气隙的转子侧边界、定子侧边界均呈余弦曲线状,能够有效的削弱产生齿槽转矩的气隙磁场谐波,进而降低齿槽转矩,减小转矩波动,同时保证了足够的输出转矩。(The invention provides a double cosine air gap flux switching servo motor which comprises a rotor and a stator arranged outside the rotor, wherein an air gap is reserved between the stator and the rotor, and the rotor side boundary and the stator side boundary of the air gap are both in a cosine curve shape. The rotor side boundary and the stator side boundary of the air gap are both in a cosine curve shape, so that the air gap magnetic field harmonic wave generating the cogging torque can be effectively weakened, the cogging torque is further reduced, the torque fluctuation is reduced, and meanwhile, the sufficient output torque is ensured.)

1. A double cosine air gap flux switching servo motor is characterized by comprising a rotor (1) and a stator arranged outside the rotor (1), wherein an air gap (2) is reserved between the stator and the rotor (1), and the rotor side boundary and the stator side boundary of the air gap are both in a cosine curve shape.

2. The biccosine air-gap flux switching servo motor as claimed in claim 1, wherein the rotor (1) is uniformly provided with a plurality of salient pole teeth (101) along the circumference of the cross section, and one end of each salient pole tooth (101) far away from the rotor (1) is of an arc structure.

3. The biccosine air-gap flux switching servo motor of claim 2, wherein a cosine curve function of a rotor-side boundary of the air gap is R_r(θ)＝R_a1+A_r*cos(P_rθ), wherein: r_a1Starting radius of the cosine curve representing the boundary on the rotor side of the air gap, A_rAn amplitude of a cosine curve representing an air gap rotor side boundary; p_rIndicates the number of salient pole teeth (101).

4. The biccos air-gap flux switching servo motor of claim 2 or 3, wherein the stator comprises permanent magnets (301), a stator core (302) and stator windings (303), the permanent magnets (301) and the stator core (302) are arranged alternately in the circumferential direction, one side of the stator core (302) facing the rotor (1) is provided with two stator teeth, the ends of the two stator teeth are both in an arc structure, and coils of the stator windings (303) are embedded in the two stator teeth and wound on the permanent magnets (301) and the stator teeth.

5. The biccosine air-gap flux switching servo motor of claim 4, wherein a cosine curve function of a stator-side boundary of the air gap is R_s(θ)＝R_a2+A_s*cos(2*P_sθ), wherein: r_a2Starting radius of the cosine curve representing the boundary on the stator side of the air gap, A_sAn amplitude of a cosine curve representing an air gap stator side boundary; p_sThe number of stator poles of the stator is indicated.

6. A double cosine air gap flux switching servo motor as claimed in claim 4, characterized in that two adjacent permanent magnets (301) are of opposite polarity.

7. The biccosine air-gap flux-switching servomotor of claim 4, wherein the amplitude A of the cosine curve of the air-gap rotor-side boundary_rStarting radius R of a cosine curve of the air-gap rotor-side boundary_a14.5% -5.5%.

8. The biccosine air-gap flux switching servo motor of claim 7, wherein an amplitude a of a cosine curve of an air-gap stator side boundary_sAmplitude A of the cosine curve of the boundary on the air gap rotor side_r9 to 11 percent of the total weight of the composition.

Technical Field

The invention relates to the technical field of servo motors, in particular to a double cosine air gap flux switching servo motor.

Background

With the rapid development of power electronics, microelectronics, sensing technology, permanent magnet technology and control theory, especially the successful application of advanced control strategy, the research and application of the alternating current servo system have gained attention development, the dynamic and static characteristics of the alternating current servo system can be completely compared with the direct current servo system, and the alternating current servo system replacing the direct current servo system becomes an important development trend. The alternating current permanent magnet synchronous motor becomes a hotspot of the current servo drive system due to the advantages of simple structure, high air gap flux density, large power density and small rotational inertia.

However, the conventional servo motor has the following problems: 1) the structure that the permanent magnet is arranged on the surface of the rotor increases the length of an air gap, increases the volume of the motor, weakens the magnetic density of the air gap and influences the output force; 2) the permanent magnet is arranged in the rotor core to influence the mechanical strength of the rotor, so that the high-speed operation is not facilitated, and the difficulty of the manufacturing process is increased; 3) the rotor permanent magnet type structure is not beneficial to heat dissipation of the permanent magnet; 4) armature reaction magnetic flux generated by the winding enters the rotor and is mutually coupled with the permanent magnet, and the rotor permanent magnet has certain demagnetization danger. Therefore, developing a new type of permanent magnet motor that can overcome the above disadvantages becomes a key to the servo system.

The structure of the winding complementary type flux switching doubly salient permanent magnet motor disclosed in patent number ZL200710022804.1 is characterized in that permanent magnets are arranged on the side of a stator, and an air gap is smooth and cylindrical, so that the defects of the rotor permanent magnet motor can be overcome. However, the motor adopts a double salient pole structure, so that the cogging torque of the motor is large, the output torque fluctuation is large, and the control precision requirements of a servo system on the rotating speed and the position are not met.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides a double cosine air gap flux switching servo motor.

The invention provides a double cosine air gap flux switching servo motor which comprises a rotor and a stator arranged outside the rotor, wherein an air gap is reserved between the stator and the rotor, and the rotor side boundary and the stator side boundary of the air gap are both in a cosine curve shape.

Preferably, the rotor is evenly provided with a plurality of salient pole teeth along the circumference of the section, and one ends of the salient pole teeth, far away from the rotor, are of arc structures.

Preferably, the cosine curve function of the rotor-side boundary of the air gap is R_r(θ)＝R_a1+A_r*cos(P_rθ), wherein: r_a1Starting radius of the cosine curve representing the boundary on the rotor side of the air gap, A_rAn amplitude of a cosine curve representing an air gap rotor side boundary; p_rIndicating the number of salient pole teeth.

Preferably, the stator comprises a permanent magnet, a stator core and a stator winding, the permanent magnet and the stator core are arranged in a circumferential direction in an alternating manner, two stator teeth are arranged on one side of the stator core facing the rotor, the end parts of the two stator teeth are both of an arc-shaped structure, and coils of the stator winding are embedded in the two stator teeth and wound on the permanent magnet and the stator teeth.

Preferably, the cosine curve function of the stator-side boundary of the air gap is R_s(θ)＝R_a2+A_s*cos(2*P_sθ), wherein: r_a2Starting radius of the cosine curve representing the boundary on the stator side of the air gap, A_sAn amplitude of a cosine curve representing an air gap stator side boundary; p_sThe number of stator poles of the stator is indicated.

Preferably, the two adjacent permanent magnets are opposite in polarity.

Preferably, the amplitude A of the cosine curve of the air-gap rotor-side boundary_rStarting radius R of a cosine curve of the air-gap rotor-side boundary_a14.5% -5.5%.

Preferably, the amplitude a of the cosine curve of the stator-side boundary of the air gap_sAmplitude A of the cosine curve of the boundary on the air gap rotor side_r9 to 11 percent of the total weight of the composition.

According to the double-cosine air gap flux switching servo motor, the rotor side boundary and the stator side boundary of an air gap are both in a cosine curve shape, and compared with a traditional smooth cylindrical air gap flux switching motor, the double-cosine air gap flux switching servo motor can effectively weaken air gap magnetic field harmonic waves generating cogging torque, further reduce the cogging torque, reduce torque fluctuation and simultaneously ensure sufficient output torque; the permanent magnet is arranged on the side of the stator, so that the cooling condition of the motor is improved, the length of the end part is reduced, the consumption of the winding motor and copper is reduced, the power density is high, and the efficiency is high.

In conclusion, the double cosine air gap flux switching servo motor has the advantages of small winding resistance, high efficiency, high power density, good cooling and heat dissipation capacity, small cogging torque and low torque fluctuation, and is very suitable for a servo drive system.

Drawings

FIG. 1 is a schematic structural diagram of a double cosine air gap flux switching servo motor according to the present invention;

FIG. 2 is a schematic structural diagram of a rotor in a double cosine air gap flux switching servo motor according to the present invention;

FIG. 3 is a schematic view of a partial structure of a stator in a double cosine air gap flux switching servo motor according to the present invention;

FIG. 4 is a schematic diagram of a stator core of a double cosine air gap flux switching servo motor according to the present invention;

FIG. 5 is a waveform diagram of the back electromotive force of a double cosine air gap flux switching servo motor according to the present invention;

FIG. 6 is a comparison graph of cogging torque waveforms for a double cosine air gap flux switching servo motor and a smooth cylindrical air gap flux switching motor according to the present invention;

fig. 7 is a comparison graph of output torque waveforms of a double cosine air gap flux switching servo motor and a smooth cylindrical air gap flux switching motor according to the present invention.

Detailed Description

Referring to fig. 1 to 4, the present invention provides a double cosine air gap flux switching servo motor, including a rotor 1 and a stator disposed outside the rotor 1, an air gap 2 is left between the stator and the rotor 1, wherein:

the rotor 1 evenly sets up a plurality of salient pole teeth 101 along the section circumference, and salient pole tooth 101 is kept away from rotor 1 one end and is the arc structure. The rotor-side boundary of the air gap is in the shape of a cosine curve, and the cosine curve function of the rotor-side boundary of the air gap is R_r(θ)＝R_a1+A_r*cos(P_rθ), wherein: r_a1The starting radius of the cosine curve representing the boundary on the air gap rotor side,A_ran amplitude of a cosine curve representing an air gap rotor side boundary; p_rIndicating the number of salient pole teeth 101.

The stator comprises permanent magnets 301, a stator core 302 and stator windings 303, the permanent magnets 301 and the stator core 302 are arranged in a circumferential direction in an alternating mode, the two adjacent permanent magnets 301 are opposite in polarity, two stator teeth are arranged on one side, facing the rotor 1, of the stator core 302, the end portions of the two stator teeth are of arc-shaped structures, and coils of the stator windings 303 are embedded in the two stator teeth and wound on the permanent magnets 301 and the stator teeth.

The stator-side boundary of the air gap is in the shape of a cosine curve, and the cosine curve function of the stator-side boundary of the air gap is R_s(θ)＝R_a2+A_s*cos(2*P_sθ), wherein: r_a2Starting radius of the cosine curve representing the boundary on the stator side of the air gap, A_sAn amplitude of a cosine curve representing an air gap stator side boundary; p_sThe number of stator poles of the stator is indicated.

The rotor side boundary and the stator side boundary of the air gap are both in a cosine curve shape, and compared with a traditional smooth cylindrical air gap flux switching motor, the air gap flux switching motor can effectively weaken air gap magnetic field harmonic waves generating cogging torque, further reduce the cogging torque, reduce torque fluctuation and simultaneously ensure enough output torque.

Specifically, the rotor 1 is formed by laminating silicon steel sheets, the cross-sectional shape of the rotor is as shown in fig. 1 and 2, and the rotor 1 is uniformly grooved along the circumference to form the arc-shaped salient pole tooth 101 as shown in fig. 4. Specifically, the rotor 1 may be subjected to cosine curve cutting and then to grooving; or the grooving can be carried out firstly, and then the cosine curve-shaped cutting is carried out.

Specifically, the stator core 302 is formed by laminating silicon steel sheets, and has a U-shaped overall shape, and a cross-sectional shape thereof is as shown in fig. 1, 3, and 4. The two ends of the stator teeth of the stator core 302 are arc-shaped, and during manufacturing, the teeth of the stator core 302 can be cut in cosine curve shape, and then slotted, as shown in fig. 4,

in a specific embodiment, the permanent magnet 301 may be made of neodymium iron boron, ferrite, or the like.

In the specific embodiment, the stator winding 303 is in a concentrated winding structure on the stator teeth jointly composed of the permanent magnet 301 and the teeth of the stator core 302. The stator winding 303 may also be a distributed winding structure.

In a specific embodiment, the amplitude A of the cosine curve of the air-gap rotor-side boundary_rStarting radius R of a cosine curve of the air-gap rotor-side boundary_a14.5% -5.5%. Amplitude A of the cosine curve of the air gap stator side boundary_sAmplitude A of the cosine curve of the boundary on the air gap rotor side_r9 to 11 percent of the total weight of the composition.

According to the invention, the stator teeth and the rotor salient pole teeth 101 are subjected to cosine cutting, so that the air gap magnetic field harmonic which generates the cogging torque can be weakened, the counter electromotive force harmonic can be reduced, a very sinusoidal counter electromotive force (as shown in figure 5) can be generated, the cogging torque can be weakened, and the torque fluctuation can be reduced. As shown in FIG. 6, the peak-to-peak value of the cogging torque of the double cosine air gap flux switching servo motor is only 0.1Nm, and the peak-to-peak value of the cogging torque of the original smooth cylindrical air gap flux switching motor is 3Nm, which is reduced by 96.7%. As shown in FIG. 7, the torque fluctuation of the double cosine air gap flux switching servo motor of the present invention is only 1.46%, and the torque fluctuation of the original smooth cylindrical air gap flux switching servo motor is 21.72%, which is reduced by 93.3%. The torque ripple calculation method is as follows:

according to the data, compared with the traditional flux switching permanent magnet motor, the double-cosine air gap flux switching servo motor has the advantages that the sine degree of the back electromotive force waveform, the cogging torque suppression, the torque fluctuation reduction and the like are greatly improved, the requirements of a speed servo and position servo driving system on a driving motor can be met, and the double-cosine air gap flux switching servo motor is a servo motor which is good in cooling condition, small in cogging torque, low in torque fluctuation, high in torque density and high in control precision.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.