Permanent magnet synchronous motor with wide flux-weakening speed regulation range

Abstract

The invention discloses a permanent magnet synchronous motor with a wide flux-weakening speed regulation range, and belongs to the technical field of permanent magnet motors. A stator comprises a stator iron core and an armature winding arranged on the stator iron core; the rotor and the stator are coaxially arranged, and the rotor comprises a rotor iron core and a permanent magnet embedded in the rotor iron core; wherein the permanent magnet is divided into a plurality of segments along the circumferential direction of the rotor, each permanent magnet segment is asymmetrically arranged, and the permanent magnet segments under each magnetic pole are axially symmetrically distributed, so that the air gap magnetic field distribution of the permanent magnet synchronous motor is adjusted. The problems that a traditional permanent magnet synchronous motor is narrow in flux weakening range, low in efficiency and complex in structure are solved.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet motor technology, and in particular to a permanent magnet synchronous motor with a wide field weakening speed range. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in new energy vehicles, aerospace, robotics, and industrial drives due to their high efficiency, high power density, and fast response. However, the magnetic field of traditional PMSMs is generated by permanent magnets and is difficult to adjust directly. Field weakening control is necessary in high-speed regions requiring constant power operation. Traditional field weakening methods typically involve injecting a direct-axis demagnetizing current, but this method increases copper losses, reduces efficiency, and excessive demagnetizing current can cause irreversible demagnetization of the permanent magnets, limiting the motor's speed range.

[0003] To improve field weakening capability, existing technologies have proposed structures such as composite rotors and hybrid excitation, or adjusted the magnetic circuit through mechanical devices. However, these solutions are complex in structure, costly, and have low reliability, making them difficult to widely promote in industrial applications. Therefore, there is an urgent need for a new permanent magnet synchronous motor structure that is simple in structure, has a wide field weakening range, and is highly efficient. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a permanent magnet synchronous motor with a wide field weakening speed regulation range, which solves the problems of narrow field weakening range, low efficiency, and complex structure of traditional permanent magnet synchronous motors.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a permanent magnet synchronous motor with a wide field weakening speed regulation range, comprising: The stator includes the stator core and the armature winding disposed on the stator core; The rotor, coaxially arranged with the stator, includes a rotor core and permanent magnets embedded in the rotor core; The permanent magnets are divided into multiple segments along the rotor circumference. Each permanent magnet segment is arranged asymmetrically, and the permanent magnet segments under each magnetic pole are distributed axially symmetrically to adjust the air gap magnetic field distribution of the permanent magnet synchronous motor.

[0006] As a further implementation, the number of permanent magnet segments under each magnetic pole is either odd or even.

[0007] As a further implementation, the permanent magnet segments under each magnetic pole have a V-shaped structure, a straight line structure, or a U-shaped structure.

[0008] As a further implementation, a magnetic barrier is provided at the q-axis position of the rotor.

[0009] As a further implementation, the magnetic barrier is symmetrical about the q-axis, and its position, shape, and size are adjustable to change the q-axis magnetic reluctance of the rotor.

[0010] As a further implementation, the armature winding is configured to receive an adjustable direct-axis current for field weakening control of the permanent magnet synchronous motor.

[0011] As a further implementation, the adjustable direct-axis current includes at least one of a positive component, a negative component, and a zero component.

[0012] As a further implementation, harmonic current components are injected into the adjustable direct-axis current.

[0013] As a further implementation, the rotor core is made of silicon steel sheets with a wide magnetization curve range.

[0014] As a further implementation, the armature winding is embedded in a slotted stator core.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The permanent magnet synchronous motor of the present invention features a wide field weakening speed range. The motor has a simple structure, high reliability, and convenient field weakening control. The permanent magnet adopts a segmented asymmetric V-shaped structure, which is novel and effectively reduces eddy current losses and increases power density while widening the field weakening speed range.

[0016] The permanent magnet synchronous motor of the present invention can flexibly adjust the number of permanent magnet segments, the length of the two arms of the V-shaped structure of each permanent magnet segment, the distance between the tip of the V-shaped structure and the center of the motor, the angle between the tip of the V-shaped structure and the d-axis, the magnetic pole angle, and the spacing between adjacent V-shaped structure tips, etc., which is highly adaptable; it can also be adjusted to a straight or U-shaped structure according to the power density requirements, which is highly expandable.

[0017] The permanent magnet synchronous motor of the present invention can add magnetic barriers at the q-axis position of the rotor according to actual needs to improve the reluctance torque of the motor. By reasonably adjusting the position, shape and size of the magnetic barriers, the combined torque of the permanent magnet torque and the reluctance torque can be maximized.

[0018] The permanent magnet synchronous motor of the present invention can easily achieve field weakening speed regulation by adjusting the d-axis current component that generates the compensating magnetic field, which greatly expands the field weakening speed regulation range of the motor. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1This is a schematic diagram of the structure of a permanent magnet synchronous motor with a wide field weakening speed range according to the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of a permanent magnet synchronous motor with a wide field weakening speed range according to the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the structure of a permanent magnet synchronous motor with a wide field weakening speed range according to the present invention. Figure 3 ; Figure 4 This is a schematic diagram of the structure of a permanent magnet synchronous motor with a wide field weakening speed range according to the present invention. Figure 4 ; Figure 5 The air gap magnetic flux density distribution of the permanent magnet synchronous motor of the present invention with a wide field weakening speed regulation range of 4 magnetic pole segments under different d-axis currents; Figure 6 The air gap magnetic flux density harmonic components of the permanent magnet synchronous motor with a wide field weakening speed range and 4 magnetic pole segments of the present invention under different d-axis currents.

[0021] Among them, 1. stator core; 2. armature winding; 3. rotor core; 4. permanent magnet; 5. magnetic barrier. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all 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 pertains.

[0024] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0025] Example 1 This invention provides a permanent magnet synchronous motor with a wide field weakening speed range. The permanent magnet adopts a segmented asymmetric V-shaped structure, which has low eddy current loss and high power density. The addition of magnetic barriers at the q-axis position of the rotor can effectively increase the q-axis magnetic reluctance and reduce the q-axis inductance, thereby improving the magnetic reluctance torque. By adjusting the number of segments of each lower pole, the parameters and spacing of the asymmetric V-shaped permanent magnet, and the d-axis harmonic current injection in the armature winding, the harmonic components of the air gap magnetic flux density can be effectively improved, torque pulsation and electromagnetic vibration can be reduced, and the overall efficiency and performance of the motor can be comprehensively improved.

[0026] like Figures 1 to 4 As shown, the specific solution of the present invention is as follows, including: The stator includes a stator core 1 and an armature winding 2 disposed on the stator core 1, wherein the armature winding 2 is embedded in the slotted stator core 1, and the stator core 1 is made of conventional silicon steel sheet material. The rotor, coaxially arranged with the stator, includes a rotor core 3 and a permanent magnet 4 embedded in the rotor core 3; Among them, the permanent magnet 4 is divided into multiple segments along the rotor circumference, and each permanent magnet segment adopts an asymmetrical structure to adjust the air gap magnetic field distribution of the permanent magnet synchronous motor.

[0027] The permanent magnet 4 is made of rare-earth permanent magnet material. The rotor core 3 can be made of conventional silicon steel sheet material or silicon steel sheet material with a wide magnetization curve range, in order to improve the saturation magnetic induction intensity of the motor, reduce the size of the motor, and further improve the motor's field weakening speed regulation capability and efficiency.

[0028] The number of permanent magnet segments under each magnetic pole can be odd or even, and the permanent magnet segments under each magnetic pole are axially symmetrically distributed.

[0029] The permanent magnet segments under each magnetic pole have a V-shaped, linear, or U-shaped structure. This embodiment uses a V-shaped structure (i.e., a V-shaped magnetic pole) as an example for explanation. Figures 1-4 As shown.

[0030] The lengths of the arms on both sides of each segment of the V-shaped magnetic pole, the distance between the tip of the V-shaped structure and the center of the motor, the angle between the tip of the V-shaped structure and the d-axis, the pole opening angle, and the spacing between adjacent V-shaped structure tips can be flexibly adjusted. They can also be adjusted to a straight or U-shaped structure according to power density requirements.

[0031] Depending on the requirements, a magnetic barrier 5 can be added at the q-axis position of the rotor to increase the reluctance torque of the motor, or the magnetic barrier 5 can be omitted.

[0032] The d-axis current component that generates the compensating magnetic field in armature winding 2 can be positive, negative, or zero. Under light load conditions, the armature magnetic field generated by the positive d-axis current component can compensate for the dip in the permanent magnet magnetic field at the d-axis position. Appropriately injecting harmonics into the d-axis current can further optimize the air gap magnetic flux density of the motor. In this case, the air gap magnetic field is jointly determined by the permanent magnet magnetic field and the compensating magnetic field generated by the positive d-axis current component. In the constant power region above the base speed where field weakening speed regulation is required, reducing the d-axis current component that generates the compensating magnetic field can reduce the air gap magnetic field, facilitating field weakening speed regulation. In conditions requiring deep field weakening, the d-axis current component that generates the compensating magnetic field can be further reduced to a negative value to further reduce the air gap magnetic field, achieving deep field weakening.

[0033] The permanent magnet synchronous motor with a wide field weakening speed range of the present invention has an air gap between the stator core 1 and the rotor core 3. The armature winding 2 is embedded in the slotted stator core 1, and the permanent magnet 4 adopts a segmented asymmetric V-shaped structure and is placed in the rotor core 3. In this embodiment, the asymmetric V-shaped structure includes not only angular asymmetry of the V-shaped pole angles of each permanent magnet segment, but also dimensional asymmetry of the lengths of the two arms of each segmented V-shaped pole, as well as positional asymmetry of the distance between the V-shaped pole vertex and the motor center (radius of the arc), the angle between the V-shaped pole vertex and the d-axis, and the width of the magnetic bridge along the outer edge of the long side arm of the V-shaped pole. The flexible design of the asymmetric V-shaped structure can flexibly control leakage flux and facilitate field weakening speed regulation of the motor.

[0034] In this embodiment, a magnetic barrier 5 is added at the q-axis position of the rotor. The magnetic barrier 5 is symmetrical about the q-axis, and its shape, size, and position can be flexibly selected according to actual needs.

[0035] Or as attached Figure 2 , 4 As shown, the rotor q-axis position does not have a magnetic barrier 5.

[0036] As attached Figure 1 , 2 As shown, in this embodiment, the number of permanent magnet segments is an even number.

[0037] Or as attached Figure 3 , 4 As shown, the number of segments in the permanent magnet is odd.

[0038] In this embodiment, the rotor core 3 can be made of conventional silicon steel sheet material or silicon steel sheet material with a wide magnetization curve range, which further improves the motor's field weakening speed regulation capability and efficiency.

[0039] In this embodiment, the asymmetric V-shaped structure includes not only angular asymmetry with unequal angles of each segment of V-shaped magnetic poles, but also dimensional asymmetry with unequal lengths of the two arms on each segment of V-shaped magnetic poles. Furthermore, it includes positional asymmetry with unequal distances between the V-shaped magnetic pole tip and the motor center (radius of the arc), unequal angles between the V-shaped magnetic pole tip and the d-axis, and unequal widths of the magnetic bridge along the outer edge of the long side arm of the V-shaped magnetic pole. The flexible design of the asymmetric V-shaped structure allows for flexible control of magnetic leakage, facilitating the motor's field weakening speed regulation.

[0040] In this embodiment, the length of the arms on both sides of each segment of the V-shaped magnetic pole, the distance between the tip of the V-shaped magnetic pole and the center of the motor, the angle between the tip of the V-shaped magnetic pole and the d-axis, the magnetic pole opening angle, and the spacing between the tips of adjacent segments of the V-shaped magnetic pole can be flexibly adjusted, and can also be adjusted to a straight or U-shaped structure according to the power density requirements.

[0041] As attached Figure 5 , 6As shown, by adjusting the d-axis current component that generates the compensating magnetic field, the amplitude of the fundamental component of the air gap magnetic flux density can be changed, which can easily realize field weakening speed regulation and greatly expand the field weakening speed regulation range of the motor.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0043] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A permanent magnet synchronous motor with wide and weak magnetic speed range, characterized in that, The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor.

2. A wide and weak field speed adjustable range permanent magnet synchronous motor as claimed in claim 1, characterized in that, The application relates to a permanent magnet synchronous motor.

3. A wide and weak flux speed range permanent magnet synchronous motor according to claim 1, characterized in that, The application relates to a permanent magnet synchronous motor.

4. A wide and weak field flux motor as claimed in claim 1 characterized in that, The application relates to a permanent magnet synchronous motor.

5. A wide and weak field flux motor as claimed in claim 4, wherein, The application relates to a permanent magnet synchronous motor.

6. A wide and weak field flux motor as claimed in claim 1 characterized in that, The application relates to a permanent magnet synchronous motor.

7. A wide and weak field flux motor as claimed in claim 6, wherein, The application relates to a permanent magnet synchronous motor.

8. A wide and weak field flux motor as claimed in claim 6, wherein, The application relates to a permanent magnet synchronous motor.

9. A wide and weak field flux motor as claimed in claim 1 characterized in that, The application relates to a permanent magnet synchronous motor.

10. A wide and weak field flux motor as claimed in claim 1 characterized in that, The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous motor. The application relates to a permanent magnet synchronous

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