A permanent magnet synchronous motor with magnetic pole interval arrangement

Abstract

This invention belongs to the field of permanent magnet synchronous motor technology, specifically referring to a permanent magnet synchronous motor with spaced magnetic poles. It includes a symmetrically arranged frame, on which a rotor is rotatably connected. The two ends of the rotor are rotatably mounted on the frames on both sides. Silicon steel stators are fitted onto the frames on both sides, coaxially arranged with the rotor. The rotor includes a rotor housing, a rotor assembly, and a generator-end stator assembly, with both ends of the generator-end stator assembly fitted onto the frame. Through the spaced arrangement of the rotor magnetic poles, the stator teeth and magnetic poles are always staggered, effectively guiding the magnetic force to the tangential direction, resulting in a higher average torque output under the same current and significantly improving the motor's torque density. Simultaneously, the magnetic pole gaps smooth the change in magnetic reluctance during rotor movement, effectively suppressing cogging torque, resulting in smooth operation and low vibration and noise. Furthermore, the structure is simple, eliminating the need for complex processes such as skewed slots or segmented magnetic poles.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motor technology, specifically referring to a permanent magnet synchronous motor with magnetic poles spaced apart. Background Technology

[0002] Traditional permanent magnet synchronous motors typically employ a continuous full-pole arrangement, where the N and S poles are closely alternately arranged on the rotor's circumferential surface, with no gaps or only minimal manufacturing gaps between adjacent poles. This continuous full-pole arrangement ensures that, at any rotor position, several stator teeth are always positioned directly opposite or nearly directly opposite the center of the magnetic poles. When the stator teeth are directly opposite the center of the magnetic poles, the force exerted by the air gap magnetic field is primarily radial magnetic pull. This radial force contributes almost nothing to the rotational torque, only increasing the vibration and noise of the stator core, resulting in a low effective tangential force ratio and difficulty in improving tooth cogging utilization.

[0003] On the other hand, in traditional continuous full-pole structures, the magnetic reluctance changes drastically when the stator teeth and rotor poles move relative to each other. Especially at the moment when the teeth and pole edges align, a large cogging torque is generated, causing speed fluctuations and mechanical vibrations, which are particularly noticeable at low speeds. To suppress cogging torque, existing technologies typically employ complex processes such as stator skew slots, segmented and misaligned poles, or unequal air gaps, which increases manufacturing costs and assembly difficulty.

[0004] Furthermore, there is no existing technology that uses a large gap between adjacent magnetic poles to ensure that the stator teeth are offset from the edge of the magnetic poles at any position, thereby directing the magnetic force mainly in the tangential direction to generate rotational torque. Summary of the Invention

[0005] To address the above issues and overcome the shortcomings of existing technologies, this invention provides a permanent magnet synchronous motor with stator poles spaced apart. By arranging the rotor poles spaced apart, the stator teeth and poles are always kept offset, and the magnetic force is effectively guided to the tangential direction, resulting in a higher average torque output under the same current and significantly improving the motor's torque density. At the same time, the pole gaps smooth out the changes in magnetic resistance during rotor movement, effectively suppressing cogging torque, resulting in smooth operation and low vibration and noise. Furthermore, the structure is simple and does not require complex processes such as skewed slots or pole segmentation.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present solution proposes a permanent magnet synchronous motor with magnetic poles spaced apart, including a symmetrically arranged frame, a rotor rotatably connected to the frame, the two ends of the rotor rotatably mounted on the two side frames, a silicon steel stator fitted on the two side frames, the silicon steel stator being coaxially arranged with the rotor, the rotor including a rotor housing, a rotor assembly and a generator stator assembly, the two ends of the generator stator assembly being fitted on the frame, the generator stator assembly being coaxially arranged with the rotor assembly, and the rotor housing being coaxially fixedly connected to both sides of the rotor assembly.

[0007] Preferably, the inner circumferential wall of the rotor assembly is fixedly connected with a spacing support block in a ring array, and the outer circumferential wall of the rotor assembly is fixedly connected with a driving permanent magnet N and a driving permanent magnet S in a ring array. The driving permanent magnet S is located between the driving permanent magnets N on both sides, and there is a gap between the driving permanent magnets N and the driving permanent magnet S.

[0008] Preferably, the silicon steel stator has stator teeth fixedly connected in a ring array, and winding grooves are provided between the stator teeth on both sides. The stator teeth are coprime with the driving permanent magnet N and the driving permanent magnet S, and their greatest common divisor is 1.

[0009] Preferably, the driving permanent magnet N and the driving permanent magnet S are neodymium iron boron N32 magnets, and radial magnetization is used.

[0010] Preferably, the stator teeth on the silicon steel stator are spaced apart from the surface of the rotor assembly, with a gap of approximately 3.25 mm.

[0011] The beneficial effects achieved by the present invention using the above structure are as follows: 1. The stator teeth and rotor magnetic poles are kept in a staggered state, and the magnetic field interaction force is mainly converted into tangential force. Under the same current conditions, a higher average torque can be output, which significantly improves the torque density of the motor. 2. Significantly reduced cogging torque: Due to the large gap between the magnetic poles, the change in magnetic resistance during rotor rotation tends to be smoother, avoiding the torque pulsation caused by the sudden change in magnetic resistance when the stator teeth move from facing the magnetic pole to facing the gap in the traditional continuous full-row structure. The motor runs more smoothly, and vibration and noise are significantly reduced. 3. The structure is simple and can achieve low cogging torque and high tangential force output without the need for complex processes such as skewed slots, segmented magnetic poles or unequal air gaps. It has low manufacturing cost and good assembly processability. Attached Figure Description

[0012] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the invention and do not constitute a limitation thereof.

[0013] Figure 1This is a schematic diagram of the overall structure of a permanent magnet synchronous motor with magnetic pole spacing proposed in this invention. Figure 2 This is a schematic diagram of the rotor structure of a permanent magnet synchronous motor with magnetic pole spacing proposed in this invention. Figure 3 This is an exploded schematic diagram of the rotor of a permanent magnet synchronous motor with magnetic pole spacing proposed in this invention. Figure 4 This is a schematic diagram of the rotor assembly structure of a permanent magnet synchronous motor with magnetic pole spacing proposed in this invention. Figure 5 This is a schematic diagram of the silicon steel stator structure of a permanent magnet synchronous motor with magnetic pole spacing proposed in this invention.

[0014] In the attached diagram: 1. Frame, 2. Rotor, 3. Silicon steel stator, 21. Rotor housing, 22. Rotor assembly, 23. Spacing support block, 27. Drive permanent magnet N, 28. Drive permanent magnet S, 29. Generator stator assembly, 31. Winding slot.

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] Example 1, as Figures 1-5 As shown, the present invention proposes a permanent magnet synchronous motor with magnetic poles spaced apart, including a symmetrically arranged frame 1. A rotor 2 is rotatably connected to the frame 1, and the two ends of the rotor 2 are rotatably mounted on the two sides of the frame 1. A silicon steel stator 3 is fitted on the two sides of the frame 1. The silicon steel stator 3 is coaxially arranged with the rotor 2. The rotor 2 includes a rotor 2 housing, a rotor 2 assembly, and a generator stator assembly 29. The two ends of the generator stator assembly 29 are fitted on the frame 1. The generator stator assembly 29 is coaxially arranged with the rotor 2 assembly. The rotor 2 housing is coaxially fixedly connected to both sides of the rotor 2 assembly.

[0018] The inner circumferential wall of the rotor 2 assembly is fixedly connected with spacing support blocks 23 in a ring array. The outer circumferential wall of the rotor 2 assembly is fixedly connected with driving permanent magnets N27 and S28 in a ring array. The driving permanent magnets S28 are located between the driving permanent magnets N27 on both sides, and there is a gap between the driving permanent magnets N27 and S28. A total of 10 driving permanent magnets N27 and S28 are provided. The proportion of the permanent magnets covering the circumference of the rotor 2 is preferably 50% to 60%, more preferably 55%.

[0019] The silicon steel stator 3 has 21 stator teeth fixedly connected in a ring array. There are winding grooves 31 between the stator teeth on both sides. The stator teeth, the driving permanent magnet N27 and the driving permanent magnet S28 are coprime and have a greatest common divisor of 1. At any rotor 2 position, at least some stator teeth are misaligned with the permanent magnets, generating tangential torque.

[0020] The driving permanent magnets N27 and S28 are neodymium iron boron N32 magnets, which are radially magnetized.

[0021] The stator teeth on the silicon steel stator 3 are spaced apart from the surface of the rotor 2 assembly, with a gap of approximately 3.25 mm.

[0022] The number of coil turns wound on each of the stator teeth is between 133 and 189.

[0023] In practical use, when the coil on the silicon steel stator 3 is energized, the tips of the 21 stator teeth form magnetic poles that are periodically distributed in the direction of the three-phase current. These stator magnetic poles generate an interaction force with the driving permanent magnet N27 and the driving permanent magnet S28.

[0024] Taking a certain moment as an example, when rotor 2 is at a certain angle, since the magnetic pole coverage ratio is 55% and there is a gap between the magnetic poles, the tooth end face of most of the 21 stator teeth is not directly facing the center of the driving permanent magnet N27 and the driving permanent magnet S28, but is in one of the following three states: the tooth end face is partially facing the edge of the magnetic pole and partially facing the gap area; the tooth end face is completely in the area corresponding to the gap and is facing the position of rotor 2 without permanent magnet coverage; the end face of a few stator teeth is within the range of the magnetic pole arc surface but is deviated from the center of the magnetic pole.

[0025] When the stator teeth are misaligned from the driving permanent magnets N27 and S28, the magnetic lines of force enter the air gap from the edge of the magnetic poles and reach the stator teeth. The path is curved. According to the principle of electromagnetic force generation, the direction of the magnetic force is perpendicular to the direction of the magnetic lines of force. In the misaligned state, since the magnetic lines of force are curved in the air gap, the direction of the force is no longer radial, but deviates to the tangential direction of the rotor 2 circumference, thereby generating a tangential torque to drive the rotor 2 to rotate.

[0026] Compared to the traditional continuous full-pole arrangement structure where a large number of stator teeth are directly facing the center of the magnetic poles and the magnetic force is mainly radial, the spaced arrangement structure of this invention "guides" the direction of the magnetic force from radial to tangential, so that most of the magnetic energy is converted into effective rotational work, achieving a tooth slot utilization rate of nearly 100%.

[0027] Example 2 illustrates the effect of suppressing cogging torque.

[0028] In a traditional continuous full-pole motor, when the rotor 2 rotates, the magnetic resistance between the stator teeth and the driving permanent magnets N27 and S28 changes drastically with position. When the stator teeth move from the transition zone between the driving permanent magnets N27 and S28, the magnetic resistance suddenly increases, generating instantaneous torque pulsation, i.e., cogging torque. Cogging torque will cause speed fluctuations, vibrations and noise.

[0029] In this invention, due to the large gap between the driving permanent magnet N27 and the driving permanent magnet S28, the transition between the covered and uncovered areas on the circumference of the rotor 2 is smoother. When the stator teeth slide to the gap area and then enter the next edge, the rate of change of magnetic reluctance is significantly reduced, and there is no longer a sudden change in magnetic reluctance. Therefore, the amplitude of the cogging torque is greatly reduced, and the motor runs more smoothly.

[0030] By combining the coprime tooth poles of the 21 teeth and 10 poles, at most only one stator tooth may be close to the center position of the driving permanent magnet N27 and the driving permanent magnet S28 at any given time. The remaining 20 teeth are all in a staggered state to varying degrees, which further disperses the source of tooth cogging torque and avoids the superposition of tooth cogging torque generated by multiple teeth at the same time.

[0031] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A permanent magnet synchronous motor with poles spaced apart, comprising a symmetrically arranged frame (1), characterized in that: The frame (1) is rotatably connected to a rotor (2). The two ends of the rotor (2) are rotatably mounted on the frame (1) on both sides. The frame (1) on both sides is fitted with a silicon steel stator (3). The silicon steel stator (3) is coaxially mounted with the rotor (2). The rotor (2) includes a rotor (2) housing, a rotor (2) assembly, and a generator stator assembly (29). The two ends of the generator stator assembly (29) are fitted on the frame (1). The generator stator assembly (29) is coaxially mounted with the rotor (2) assembly. The rotor (2) housing is coaxially fixedly connected to both sides of the rotor (2) assembly.

2. A permanent magnet synchronous motor with pole spacing as described in claim 1, characterized in that: The inner circumferential wall of the rotor (2) assembly is fixedly connected with spaced support blocks (23) in a ring array.

3. A permanent magnet synchronous motor with pole spacing according to claim 2, characterized in that: The outer circumferential wall of the rotor (2) assembly is fixedly connected with a driving permanent magnet N (27) and a driving permanent magnet S (28) in a ring array. The driving permanent magnet S (28) is located between the driving permanent magnets N (27) on both sides, and there is a gap between the driving permanent magnets N (27) and the driving permanent magnet S (28).

4. A permanent magnet synchronous motor with pole spacing as described in claim 3, characterized in that: The silicon steel stator (3) has stator teeth fixedly connected in a ring array. There are winding grooves (31) between the stator teeth on both sides. The stator teeth are coprime with the driving permanent magnet N (27) and the driving permanent magnet S (28), and the greatest common divisor is 1. At any rotor (2) position, at least some stator teeth are misaligned with the permanent magnets, generating tangential torque.

5. A permanent magnet synchronous motor with pole spacing as described in claim 4, characterized in that: The driving permanent magnet N (27) and driving permanent magnet S (28) are neodymium iron boron N32 magnets, which are radially magnetized.

6. A permanent magnet synchronous motor with pole spacing according to claim 5, characterized in that: The stator teeth on the silicon steel stator (3) are spaced apart from the surface of the rotor (2) assembly.

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