A motor rotor structure for realizing better sinusoidal distribution of rotor flux linkage
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG FANSHENG INTELLIGENT CONTROL TECH CO LTD
- Filing Date
- 2025-08-22
- Publication Date
- 2026-05-26
AI Technical Summary
The non-sinusoidal distribution of rotor flux in traditional motors leads to torque fluctuations, increased noise, and reduced efficiency. In particular, in high-speed applications, there is a risk of magnet detachment and magnetic field distortion.
By optimizing the rotor pole shape and permanent magnet arrangement, combining magnetic isolation slots and multi-layer permanent magnet structure, and cooperating with a full magnetic levitation bearing system, a sinusoidal distribution of rotor flux is achieved, reducing harmonic content and improving torque stability.
It achieves efficient and stable operation of the motor, reduces torque pulsation and noise, improves control accuracy and overall efficiency, and features ultra-high speed and long life, making it suitable for high-end equipment drive applications.
Smart Images
Figure CN224289419U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of motor technology, specifically to a motor rotor structure that achieves a better sinusoidal distribution of rotor flux linkage. Background Technology
[0002] Electric motors are ubiquitous in modern production and daily life. By installing a stator and rotor inside, they can be powered to rotate and operate the machine. An electric motor mainly consists of a stator and a rotor, with the distribution of the rotor's magnetic field directly affecting its electromagnetic performance. In traditional motors, if the rotor's magnetic flux linkage is not sinusoidal, it can easily lead to torque fluctuations, increased noise, and reduced efficiency. To achieve efficient and stable operation, the rotor structure needs to be optimized to make the magnetic flux linkage approximate a sinusoidal waveform, thereby reducing harmonic losses and improving motor control accuracy and energy efficiency.
[0003] As the core of a high-efficiency power source, the rotor design of a permanent magnet synchronous motor must consider multiple objectives, including electromagnetic performance and mechanical strength. The sinusoidal distribution of the rotor flux linkage is one of the key paths to optimizing electromagnetic performance, especially in high-speed applications (such as drive motors for new energy vehicles). A sinusoidal magnetic field can significantly reduce eddy current losses and back EMF distortion at high speeds, improving system reliability. Current rotor magnet fixing methods (such as embedded or surface-mounted types) face the risk of magnet detachment due to centrifugal force during high-speed rotation, while the magnetic circuit structure distribution (such as radial or tangential types) directly affects the sinusoidality of the magnetic field. Summary of the Invention
[0004] This invention primarily addresses the shortcomings of existing technologies by providing a motor rotor structure that achieves a better sinusoidal distribution of rotor flux linkage. This structure is characterized by its simple structure, good operational stability, and high efficiency. This is achieved by optimizing the rotor pole shape, permanent magnet arrangement, and auxiliary structures to reduce harmonic content and improve torque smoothness. The resulting good sinusoidal distribution of rotor flux linkage reduces motor torque ripple and cogging effects, thereby improving the motor's operational smoothness, efficiency, and control precision.
[0005] The above-mentioned technical problems of this utility model are mainly solved by the following technical solutions:
[0006] A motor rotor structure for achieving a better sinusoidal distribution of rotor flux linkage includes a protective housing, within which a rotor is housed, and a stator is positioned between the rotor and the protective housing. The rotor contains magnetic isolation slots and magnetic filling slots, with permanent magnet strips embedded in the magnetic filling slots. The permanent magnet strips include permanent magnet I, permanent magnet II, and permanent magnet III. The superposition of permanent magnet I, permanent magnet II, and permanent magnet III achieves a better sinusoidal distribution of rotor flux linkage. The combined action of permanent magnet I, permanent magnet II, permanent magnet III, and the magnetic isolation slots forms a quadrature-axis magnetic circuit, thereby increasing the torque due to the superposition of reluctance torque.
[0007] Preferably, the outer circumference of the rotor is provided with a permanent magnet I, a pair of permanent magnets III are provided between the permanent magnet I and the center of the rotor, a permanent magnet II is provided between the permanent magnet I and the permanent magnet III, and the magnetic isolation groove is located on both sides of the permanent magnet II and between the two permanent magnets III.
[0008] Permanent magnet I is the primary generator of rotor flux linkage, while permanent magnets II and III are auxiliary generators of rotor flux linkage.
[0009] Preferably, the cross-sections of permanent magnet I, permanent magnet II, and permanent magnet III are arc-shaped.
[0010] Preferably, the rotor is provided with caps at both ends, and the caps and the stator are provided with bushings located between the two ends of the protective housing and the rotor. The rotor extension section on one side of the cap is provided with an impeller that is splinedly inserted into the rotor.
[0011] Preferably, both the cover and the bushing are provided with radial magnetic levitation bearings that are fitted onto the rotor.
[0012] Preferably, a pair of thrust magnetic bearings are provided between the radial magnetic bearing and the bushing on the other side of the impeller.
[0013] Preferably, position sensors are provided between the thrust magnetic levitation bearing and the rotor, and between the cover and the rotor, respectively, and the position sensors are installed on the inner wall of the thrust magnetic levitation bearing and the cover.
[0014] Preferably, a spacer disc that is fitted between the two thrust magnetic levitation bearings is provided and is connected to the rotor.
[0015] This invention can achieve the following effects:
[0016] This invention provides a motor rotor structure that achieves a better sinusoidal distribution of rotor flux linkage. Compared with existing technologies, it features a simple structure, good operational stability, and high efficiency. This is achieved by optimizing the rotor pole shape, permanent magnet arrangement, and auxiliary structures to reduce harmonic content and improve torque smoothness. It achieves a good sinusoidal distribution of rotor flux linkage, reducing motor torque ripple and cogging effects, thereby improving the motor's operational smoothness, efficiency, and control precision.
[0017] Superior operating performance: Due to the excellent sinusoidal nature of the rotor flux linkage, the motor has very small torque ripple, runs very smoothly, and has high control precision.
[0018] High efficiency: The sinusoidal magnetic field reduces core losses (eddy current losses and hysteresis losses), while the magnetic levitation bearing eliminates mechanical friction losses, resulting in very high overall efficiency.
[0019] Ultra-high speed and long life: Magnetic levitation bearings allow rotors to reach extremely high speeds (hundreds of thousands of revolutions per minute) without mechanical wear, resulting in an extremely long lifespan and virtually no maintenance required.
[0020] Low noise: The absence of mechanical contact and extremely low torque ripple result in very low motor operating noise.
[0021] Clean and oil-free: No lubricating oil is required, avoiding oil mist pollution, making it ideal for applications with high requirements for environmental cleanliness (such as semiconductor manufacturing).
[0022] Through an innovative combination of built-in multi-layer permanent magnets and magnetic isolation grooves, the sinusoidal nature of the magnetic field waveform is guaranteed from the source. Simultaneously, the use of a fully magnetically levitated bearing system completely eliminates the limitations of mechanical friction. This combination endows the motor with a series of superior performance characteristics, including high precision, high speed, high efficiency, long lifespan, and low noise, making it an ideal choice for modern high-end equipment drive systems. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of this utility model.
[0024] Figure 2 This is a schematic diagram of the assembly structure of the rotor and permanent magnet in this utility model.
[0025] Figure 3 This is a cross-sectional view of the rotor in this utility model.
[0026] In the diagram: 1. Impeller; 2. Cover; 3. Radial magnetic levitation bearing; 4. Protective housing; 5. Stator; 6. Rotor; 7. Shaft sleeve; 8. Thrust magnetic levitation bearing; 9. Position sensor; 10. Spacer disc; 11. Magnetic isolation groove; 12. Permanent magnet I; 13. Permanent magnet II; 14. Permanent magnet III; 15. Magnetic filling groove. Detailed Implementation
[0027] The technical solution of this utility model will be further described in detail below through embodiments and in conjunction with the accompanying drawings.
[0028] Example: Figure 1 , Figure 2 and Figure 3As shown, a motor rotor structure achieving a better sinusoidal distribution of rotor flux includes a protective housing 4, within which a rotor 6 is housed. A stator 5 is positioned between the rotor 6 and the protective housing 4. Covers 2 are located at both ends of the rotor 6. Bushings 7, located between the cover 2 and the stator 5 and between the cover 4 and the rotor 6, are positioned between the cover 2 and the stator 5. An impeller 1, splinedly inserted into the rotor 6, is positioned on the extension section of the rotor 6 on one side of the cover 2. Radial magnetic levitation bearings 3, fitted onto the rotor 6, are positioned between the cover 2 and the bushings 7. A pair of thrust magnetic levitation bearings 8, mirror-distributed, are positioned between the radial magnetic levitation bearings 3 and the bushings 7 on the other side of the impeller 1. A spacer disc 10, fitted onto the rotor 6, is positioned between the two thrust magnetic levitation bearings 8. Position sensors 9 are positioned between the thrust magnetic levitation bearings 8 and the rotor 6, and between the cover 2 and the rotor 6, respectively, mounted on the inner walls of the thrust magnetic levitation bearings 8 and the cover 2. The rotor 6 has a magnetic isolation groove 11 and a magnetic filling groove 15. Permanent magnet strips are embedded in the magnetic filling groove 15, including permanent magnet I 12, permanent magnet II 13, and permanent magnet III 14. Permanent magnet I 12 is located on the outer circumference of the rotor 6. A pair of permanent magnets III 14 are located between permanent magnet I 12 and the center of the rotor 6. Permanent magnet II 13 is located between permanent magnet I 12 and permanent magnet III 14. The magnetic isolation groove 11 is located on both sides of permanent magnet II 13 and between the two permanent magnets III 14. The cross-sections of permanent magnets I 12, II 13, and III 14 are arc-shaped.
[0029] Workflow:
[0030] Position sensor 9 monitors the rotor position in real time.
[0031] The control system supplies power to the radial magnetic levitation bearing 3 and the thrust magnetic levitation bearing 8 based on the position signal.
[0032] The magnetic bearing generates a precise and controllable electromagnetic force, which keeps the rotor stably suspended in the center.
[0033] The control system supplies a three-phase sinusoidal current to the stator 5 winding, generating a rotating magnetic field.
[0034] The permanent magnets I12, II13 and III14 inside rotor 6 generate a high-quality sinusoidal magnetic field.
[0035] The magnetic field of stator 5 interacts with the magnetic field of rotor 6 to generate a smooth electromagnetic torque, which drives the rotor and impeller 1 to rotate at high speed.
[0036] In summary, a motor rotor structure achieving a favorable sinusoidal distribution of rotor flux linkage is characterized by its simple structure, good operational stability, and high efficiency. This is achieved by optimizing the rotor pole shape, permanent magnet arrangement, and auxiliary structures to reduce harmonic content and improve torque smoothness. This results in a favorable sinusoidal distribution of rotor flux linkage, reducing motor torque ripple and cogging effects, thereby improving the motor's operational smoothness, efficiency, and control precision.
[0037] Employing a fully magnetically levitated bearing system (radial and thrust), coupled with high-precision position sensors, the rotor achieves zero mechanical contact with stationary components such as the stator during operation. This results in advantages such as ultra-high speed, no wear, low noise, no lubrication required, and long maintenance life, making it ideal for high-end applications such as high-speed centrifuges, turbomolecular pumps, precision machine tool spindles, and flywheel energy storage.
[0038] It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0039] In summary, the above description is only a specific embodiment of the present utility model, but the structural features of the present utility model are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present utility model are covered by the patent scope of the present utility model.
Claims
1. A motor rotor structure that achieves a good sinusoidal distribution of rotor flux linkage, comprising a protective housing (4), characterized in that: The protective housing (4) is disposed inside the rotor (6), and a stator (5) is disposed between the rotor (6) and the protective housing (4). The rotor (6) is provided with a magnetic isolation groove (11) and a magnetic filling groove (15). A permanent magnet strip is inserted into the magnetic filling groove (15). The permanent magnet strip includes permanent magnet I (12), permanent magnet II (13) and permanent magnet III (14).
2. The motor rotor structure according to claim 1, which achieves a better sinusoidal distribution of rotor flux linkage, is characterized in that: The rotor (6) is provided with a permanent magnet I (12) on its outer circle. A pair of permanent magnets III (14) are provided between the permanent magnet I (12) and the center of the rotor (6). A permanent magnet II (13) is provided between the permanent magnet I (12) and the permanent magnet III (14). The magnetic isolation groove (11) is located on both sides of the permanent magnet II (13) and between the two permanent magnets III (14).
3. The motor rotor structure according to claim 2, which achieves a better sinusoidal distribution of rotor flux linkage, is characterized in that: The cross-sections of permanent magnet I (12), permanent magnet II (13) and permanent magnet III (14) are arc-shaped.
4. The motor rotor structure according to claim 1, which achieves a better sinusoidal distribution of rotor flux linkage, is characterized in that: The rotor (6) is provided with a cover (2) at both ends. A bushing (7) is provided between the cover (2) and the stator (5) between the protective housing (4) and the rotor (6). An impeller (1) is splinedly inserted on the extension section of the rotor (6) on one side of the cover (2).
5. The motor rotor structure according to claim 4, which achieves a better sinusoidal distribution of rotor flux linkage, is characterized in that: The cover (2) and the bushing (7) are both provided with radial magnetic levitation bearings (3) that are sleeved with the rotor (6).
6. The motor rotor structure according to claim 5, which achieves a better sinusoidal distribution of rotor flux linkage, is characterized in that: The impeller (1) has a pair of thrust magnetic levitation bearings (8) arranged in a mirror image on the other side, and is located between the radial magnetic levitation bearing (3) and the bushing (7).
7. The motor rotor structure according to claim 6, which achieves a better sinusoidal distribution of rotor flux linkage, is characterized in that: Position sensors (9) are provided between the thrust magnetic levitation bearing (8) and the rotor (6) and between the cover (2) and the rotor (6). The position sensors (9) are respectively installed on the inner wall of the thrust magnetic levitation bearing (8) and the cover (2).
8. The motor rotor structure according to claim 6, which achieves a better sinusoidal distribution of rotor flux linkage, is characterized in that: A spacer disc (10) is provided between the two thrust magnetic levitation bearings (8) and is fitted with the rotor (6).