A disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor and method thereof

Abstract

The present invention belongs to the technical field of permanent magnet synchronous motors, and relates to a disc-type permanent magnet magnetic adjustment type permanent magnet synchronous motor and a method thereof, comprising a stator, a rotor, and a permanent magnet disc, wherein the rotor is built into the stator and coaxially placed with the stator, the permanent magnet discs comprising two, placed at different ends of the rotor, the permanent magnet discs having multiple permanent magnets attached to the side close to the rotor, and the stator having an armature winding mounted thereon; the stator armature winding applies a q-axis current to interact with the rotor's main magnetic field to generate a driving torque, and the amplitude of the motor's main magnetic field is adjusted by adjusting the relative position angle between the permanent magnets on the permanent magnet discs at the rotor ends and the axial magnetic poles of the motor rotor. The motor of the present invention uses permanent magnet discs for magnetic adjustment, and the magnetic adjustment method is relatively simple, and no additional armature windings are required. The magnetic adjustment efficiency is high, and no new losses are caused to the motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of permanent magnet synchronous motors, and relates to a disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor and a method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Permanent magnet motor systems are widely used in important equipment fields such as industrial servos, electric drives, and new energy power generation due to their advantages such as high efficiency, low loss, high power density, and compact structure. However, due to the inherent characteristics of permanent magnet materials, the performance of permanent magnet motor systems in magnetic field regulation and wide-speed operation is significantly insufficient. In particular, emerging equipment fields such as new energy vehicles and multi-electric / all-electric aircraft have placed more stringent requirements on the power density, constant power operation capability, and power quality of motor systems. However, since permanent magnet motors use permanent magnets with fixed magnetic flux for excitation, their main pole magnetic flux is fixed and difficult to adjust after the motor is manufactured. Key electromagnetic properties such as starting capability and weak magnetic speed expansion capability are severely limited for the following reasons:

[0004] 1. When a permanent magnet motor operates above base speed, it is necessary to increase the proportion of the d-axis demagnetization current in the armature winding to achieve field weakening and limit the increase in back EMF. However, due to the limitations of the motor winding current amplitude and the inverter capacity, the increase in the d-axis demagnetization current in the armature winding will cause the q-axis drive current to drop rapidly, significantly reducing the torque output capability of the motor system at high speeds.

[0005] 2. Most traditional permanent magnet motors have low d-axis inductance, making field weakening adjustment difficult. Furthermore, the rapidly increasing winding copper loss during deep field weakening significantly reduces the field weakening efficiency of the motor system.

[0006] 3. The weak magnetic field introduced by the armature winding and the permanent magnet excitation magnetic field are directly interactively coupled in the air gap. Therefore, when the d-axis demagnetization current is large, the risk of irreversible demagnetization of the permanent magnet will be significantly increased.

[0007] 4. Deep magnetic weakening operation of permanent magnet motors will lead to air gap magnetic field distortion, increased harmonic content, reduced power factor, decreased permanent magnet flux utilization, increased power device line loss and other problems that seriously affect the operating quality of the motor system.

[0008] Hybrid excitation is one of the key approaches to addressing the inadequate magnetic field regulation and poor field-weakening operation of traditional permanent magnet motor systems. By deploying an electric excitation magnetic circuit and adding an electric excitation coil, it combines the advantages of both permanent magnet and electric excitation motors, effectively improving the motor's field-weakening speed-expansion capability. However, current hybrid excitation motors have limited flux regulation capabilities, complex magnetic circuit layouts and auxiliary magnetic conduction circuit designs, and the electric excitation winding significantly increases the motor's field regulation losses, resulting in low overall operating efficiency. These motors suffer from low permanent magnet flux utilization, complex excitation component structures, physical constraints between the field regulation winding and the armature winding, and a significant conflict between the motor's field regulation performance and power density. Summary of the Invention

[0009] In order to solve the above problems, the present invention proposes a disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor and a method thereof.

[0010] According to some embodiments, the present invention adopts the following technical solutions:

[0011] A disc-type permanent magnet magnetic field modulation type permanent magnet synchronous motor, comprising a stator, a rotor and a permanent magnet disc, wherein the rotor is built into the stator and is coaxially placed with the stator, the permanent magnet disc comprises two, and is placed at different ends of the rotor, and a plurality of permanent magnets are attached to the surface of the permanent magnet disc close to the rotor, and the stator is provided with an armature winding;

[0012] The rotor is formed by splicing two rotor segments of the same structure, each rotor segment having a plurality of rib structures distributed in an alternating manner, the rib structures of the two rotor segments being staggered at a certain angle, and the rib structures of the two rotor segments present opposite magnetic polarities;

[0013] Each rib structure is connected to a magnetic spoke. The magnetic spokes connected to different rotor segments have opposite magnetic polarities. The magnetic spokes extend beyond the two ends of the rotor to form axial magnetic poles. The axial magnetic poles correspond to the permanent magnets on the permanent magnetic disks at both ends of the rotor.

[0014] A plurality of permanent magnets are arranged on the circumference of the rotor, and the permanent magnets generate magnetic flux on the rotor by utilizing the magnetic concentration effect, with a part forming radial magnetic poles and the other part forming axial magnetic poles;

[0015] The radial magnetic pole magnetic flux of the motor enters the stator through the radial air gap and interacts with the magnetic flux generated by the armature winding on the stator to form the main magnetic flux of the motor;

[0016] The axial magnetic poles correspond to the permanent magnets on the permanent magnetic disk. When the same polarity is opposite to each other, the main magnetic flux increases; when the permanent magnet disk at the end of the motor is opposite to the motor shaft magnetic pole with different polarity, the main magnetic flux decreases.

[0017] As an optional embodiment, the stator is formed by laminating silicon steel sheets, and the stator includes stator slots, stator teeth and a stator yoke, and the armature winding is placed in the stator slots.

[0018] As an optional embodiment, the permanent magnet disc is made of silicon steel sheets wound and stacked, or is made of pure steel in an integrated manner.

[0019] As an optional implementation, the permanent magnet disks are symmetrically arranged, the number of permanent magnets attached to each permanent magnet disk is the same, and the shapes of the permanent magnets and the axial magnetic poles of the rotor correspond to and are the same.

[0020] As an optional embodiment, the cross-sectional shape of the permanent magnet attached to the permanent magnetic disk is consistent with the cross-sectional shape of the magnetic spokes.

[0021] As an optional embodiment, the permanent magnet disc is a rotatable component, which is driven by a servo motor to drag the permanent magnet disc and the rotor to maintain the same speed during normal operation, or to adjust the relative angle between the permanent magnet disc and the rotor axial magnetic pole when dynamic adjustment of the main magnetic circuit is required.

[0022] As an alternative embodiment, the rotor can be constructed from laminated silicon steel sheets, connected to the magnetic spokes via fasteners or bolts. Alternatively, a solid rotor made of a soft magnetic composite material can be integrally formed through casting or other methods. To enhance the rotor's mechanical strength, the rotor can be encapsulated with epoxy resin to ensure the mechanical reliability of the rotor's magnetic spokes.

[0023] As an optional implementation, the magnetic flux generated by the permanent magnets on the rotor is divided into two parts, forming a radial main magnetic flux and an axial main magnetic flux, and the radial and axial magnetic circuits are in parallel.

[0024] As an optional implementation, the main magnetic flux of the motor is adjusted by controlling the relative position angle between the permanent magnets on the permanent magnet disk at the end of the motor and the axial magnetic poles of the rotor.

[0025] A torque driving method for a disk-type permanent magnet magnetic modulation type permanent magnet synchronous motor comprises the following steps:

[0026] The stator armature winding applies q-axis current to interact with the rotor main magnetic field to generate driving torque, and the amplitude of the motor main magnetic field is adjusted by adjusting the relative position angle between the permanent magnet on the permanent magnet disk at the rotor end and the axial magnetic pole of the motor rotor.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The two axial sides of the motor of the present invention are permanent magnet disks, on which permanent magnets are attached to adjust the magnetic flux. Compared with the armature winding, the volume is smaller and no additional loss and heat energy are generated.

[0029] The motor of the present invention has two magnetically adjustable permanent magnet disks at the rotor ends and a radially arranged stator, forming a radially and axially parallel magnetic circuit. The total amount of magnetic flux generated by the permanent magnets on the motor rotor is constant, but its direction varies depending on the radial and axial directions of the motor. The armature winding current of the radial stator regulates the magnetic flux in this branch circuit, and the d-axis current component of the winding current inhibits the flow of permanent magnet flux through this branch circuit. The axial magnetic circuit is regulated by adjusting the relative position angle between the permanent magnets on the end permanent magnet disks and the rotor's axial magnetic poles. Depending on the motor's operating speed ranges, such as starting, rated, and high-speed operation, the relative position angle between the permanent magnets on the permanent magnet disks on either side of the rotor and the rotor's axial magnetic poles can be adjusted to achieve different magnetic field distributions, thereby improving the motor's operating performance and achieving superior starting and field-weakening capabilities. Compared to conventional magnetically adjustable permanent magnet motors, the motor of the present invention utilizes magnetic adjustment through the permanent magnet disks. This method is relatively simple, does not require additional armature windings, and offers high magnetic adjustment efficiency without incurring additional losses in the motor.

[0030] This motor features permanent magnet discs on either side of the rotor. Permanent magnets attached to the end surfaces of these discs generate magnetic flux and regulate the motor's main magnetic flux. This achieves high magnetic flux regulation efficiency without incurring additional losses. High-magnetic materials such as neodymium iron boron can be used on both sides, significantly increasing the motor's magnetic flux regulation range. Alternatively, low-magnetic ferrite materials can be used, significantly reducing manufacturing costs. The permanent magnet discs can be designed with a minimal axial length, minimizing the motor's overall length and volume, thereby maintaining the motor's high power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 This is a schematic diagram of the overall structure of the motor of the present invention;

[0033] Figure 2 This is a schematic diagram of the three-dimensional structure of the motor rotor and the end permanent magnet disk of the present invention;

[0034] Figure 3 A schematic three-dimensional diagram of the motor rotor structure of the present invention;

[0035] Figure 4 This is a schematic diagram of the structure of the permanent magnet disk at the end of the motor rotor of the present invention;

[0036] In the figure, 1. The first section of the rotor, 2. The second section of the rotor, 3. The permanent magnet, 4. The rib structure of the first section of the rotor, 5. The rib structure of the second section of the rotor, 6. The magnetic spokes connecting the first section of the rotor to the ribs, 7. The magnetic spokes connecting the second section of the rotor to the ribs, 8. The stator, 9. The stator armature winding, 10. The stator slots, 11. The stator teeth, 12. The permanent magnet disk at the end of the rotor, 13. The permanent magnet attached to the permanent magnet disk. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] like Figure 1 As shown, a disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor, in this embodiment, the number of motor phases is 3, the number of stator teeth is 48, the number of permanent magnet blocks and the number of poles on the end permanent magnet disk are 16 and 8, the number of rotor slots is 8, the two-section rotor has a total of 8 ribs, the number of permanent magnet blocks is 16, and the number of rotor poles is 8. This embodiment includes a stator 8, a permanent magnet disk 12 and a permanent magnet 13 attached to the surface of the disk, rotors 1 and 2, and an armature winding 9 on the stator; the stator 8 is formed by stacking silicon steel sheets, the permanent magnet disk 12 is formed by winding and stacking silicon steel sheets, and a permanent magnet 13 is attached to the surface thereof. The stator 8 includes stator teeth 11 and stator slots 10, and the armature winding 9 is placed in the stator slots. The armature winding 9 can be divided into distributed winding, concentrated winding or stacked winding, and the number of poles of the armature winding is consistent with the number of rotor poles. The stator and the axial permanent magnet disk are both coaxial with the rotor. There is a radial air gap between the stator and the rotor, and an axial air gap between the axial permanent magnet disk and the rotor.

[0041] like Figure 2 、 3The schematic diagram of the overall structure of the rotor is shown. The entire rotor consists of two identical rotor sections 1 and 2, magnetic spokes 6 and 7, and rotor ribs 4 and 5. The two rotor sections are coaxially connected. The ribs 5 of the second rotor section 2 are staggered 45 degrees with the ribs 4 of the first rotor section 1 (the example diagram shows an 8-pole motor with a staggered degree of 360 / 2p degrees). Thus, a staggered rib structure 4 and 5 is formed at the end shaft of the rotor. Each rotor section has 8 rotor slots that can be used to place permanent magnets 3. The adjacent two permanent magnets are staggered 45 degrees. The magnetization directions are opposite, and radial magnetic poles are generated radially between two adjacent permanent magnets and the rotor core between them. The magnetic flux generated by the permanent magnets passes through the radial magnetic poles and the air gap into the stator core and interlinks with the armature winding to form the main magnetic flux. On the rotor, since the magnetic polarities of the two sections of the rotor ribs and their corresponding magnetic axes are opposite, a part of the magnetic flux of each section of the rotor can reach the end of the rotor through the staggered rotor rib structure 4, 5 and the magnetic spokes 6, 7, forming axial magnetic poles and corresponding to the permanent magnets 13 on the end permanent magnet disk 12.

[0042] When the motor is in the starting state or rated normal operation, the permanent magnets 13 on the end permanent magnet disk 12 are adjusted to have the same polarity relative to the rotor axial magnetic poles. This allows more magnetic flux generated by the permanent magnets on the rotor to enter the stator. At the same time, the magnetic flux generated by the permanent magnets on the end permanent magnet disks also enters the stator along the "rotor magnetic spokes-rotor ribs-rotor yoke" path, increasing the motor's main magnetic flux and enhancing the motor's torque output capacity. When the motor is in a high-speed operation state and requires magnetic weakening, the permanent magnets 13 on the end permanent magnet disk 12 are adjusted to have different polarity relative to the rotor axial magnetic poles. This allows more magnetic flux generated by the permanent magnets 3 on the rotor to be drawn into the axial permanent magnet disk, reducing the magnetic flux entering the stator and reducing the motor's main magnetic flux. According to the actual operating state of the motor, the relative position angle of the permanent magnets 13 on the motor's axial permanent magnet disk 12 and the rotor's axial magnetic poles can be adjusted in real time, thereby adjusting the parallel magnetic circuit to obtain different motor magnetic field distribution states, thereby achieving good operating performance under different operating conditions.

[0043] Among them, in the above embodiment, the rotor 3 can be made of stacked silicon steel sheets, connected to the magnetic spokes 6 and 7 by fasteners or bolts, and cast and fixed by epoxy resin material to improve the overall mechanical structure strength; it can also be a solid rotor made of a soft magnetic composite material with high magnetic permeability made in one piece. The solid rotor has high magnetic permeability. Permanent magnets are placed in the rotor. The rotor is a permanent magnet built-in structure. The permanent magnets are arranged in a certain combination to achieve a magnetic concentration effect. The magnetic flux generated by the permanent magnets can enter the air gap radially. The solid rotor can generate eddy currents when the motor starts to achieve self-starting.

[0044] The permanent magnet is a high-performance permanent magnet material, such as neodymium iron boron, rare earth cobalt, or a low-performance permanent magnet material, such as alnico or ferrite.

[0045] When a permanent magnet synchronous motor is operating, with no load and no current flowing through it, a portion of the magnetic flux generated by the permanent magnets passes through the radial magnetic poles, across the air gap, into the stator core, and interlinks with the armature winding to form the motor's main magnetic flux. The other portion passes through the rotor's staggered rib structure and the rotor's magnetic spokes to form the rotor's axial magnetic poles, corresponding to the permanent magnets 13 on the permanent magnet disc 12 at the rotor end. When the motor is running with load, the operating mode is:

[0046] The permanent magnets 13 on the end permanent magnet discs 12 are adjusted to have the same polarity as the rotor axial magnetic poles. More magnetic flux generated by the permanent magnets on the rotor enters the stator. At the same time, the magnetic flux generated by the permanent magnets on the end permanent magnet discs also enters the stator along the "rotor magnetic spokes-rotor ribs-rotor yoke", increasing the main magnetic flux of the motor and enhancing the torque output capacity of the motor.

[0047] When the motor needs to perform weak magnetic operation, the permanent magnets 13 on the permanent magnet disk 12 at the end are adjusted to have different polarities relative to the axial magnetic poles of the rotor. More magnetic flux generated by the permanent magnets 3 on the rotor is introduced into the axial permanent magnet disk, and the magnetic flux entering the stator is reduced, and the main magnetic flux of the motor is reduced.

[0048] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it 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 on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor, characterized in that: The invention comprises a stator, a rotor and a permanent magnet disc, wherein the rotor is built into the stator and is coaxially placed with the stator. The permanent magnet discs include two and are placed at different ends of the rotor. A plurality of permanent magnets are attached to the side of the permanent magnet disc close to the rotor. The stator is provided with an armature winding. The rotor is formed by splicing two rotor segments of the same structure, each rotor segment having a plurality of rib structures distributed in an alternating manner, the rib structures of the two rotor segments being staggered at a certain angle, and the rib structures of the two rotor segments present opposite magnetic polarities; Each rib structure is connected to a magnetic spoke. The magnetic spokes connected to different rotor segments have opposite magnetic polarities. The magnetic spokes extend beyond the two ends of the rotor to form axial magnetic poles. The axial magnetic poles correspond to the permanent magnets on the permanent magnetic disks at both ends of the rotor. A plurality of permanent magnets are arranged on the circumference of the rotor, and the permanent magnets generate magnetic flux on the rotor by utilizing the magnetic concentration effect, with a part forming radial magnetic poles and the other part forming axial magnetic poles; The radial magnetic pole magnetic flux of the motor enters the stator through the radial air gap and interacts with the magnetic flux generated by the armature winding on the stator to form the main magnetic flux of the motor; The axial magnetic poles correspond to the permanent magnets on the permanent magnet disk. When the same polarity is opposite to each other, the main magnetic flux increases; when the permanent magnet disk at the end of the motor and the magnetic poles of the motor shaft system are opposite to each other with different polarity, the main magnetic flux decreases. The cross-sectional shape of the permanent magnet attached to the permanent magnetic disc is consistent with the cross-sectional shape of the magnetic spokes; The permanent magnet disc is a rotatable component, which is driven by a servo motor. During normal operation, the permanent magnet disc is dragged to maintain the same speed as the rotor, or when dynamic adjustment of the main magnetic circuit is required, the relative angle between the permanent magnet disc and the rotor axial magnetic pole is adjusted.

2. A disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor according to claim 1, characterized in that: The stator is formed by laminating silicon steel sheets, and comprises stator slots, stator teeth and a stator yoke. An armature winding is placed in the stator slots.

3. A disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor according to claim 1, characterized in that: The permanent magnet disc is made of silicon steel sheets wound and stacked, or is made of pure steel in one piece.

4. A disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor according to claim 1, characterized in that: The permanent magnet disks are symmetrically arranged, and the number of permanent magnets attached to each permanent magnet disk is the same. The shapes of the permanent magnets and the axial magnetic poles of the rotor correspond to and are the same.

5. The disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor according to claim 1, characterized in that: The rotor is made of laminated silicon steel sheets and connected with magnetic spokes; or, it is a solid rotor made of soft magnetic composite material.

6. The disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor according to claim 1, characterized in that: The magnetic flux generated by the permanent magnets on the rotor is divided into two parts, forming a radial main magnetic flux and an axial main magnetic flux, and the radial and axial magnetic circuits are in a parallel relationship.

7. The disc-type permanent magnet magnetic modulation type permanent magnet synchronous motor according to claim 1, characterized in that: The main magnetic flux of the motor is adjusted by controlling the relative position angle between the permanent magnet on the permanent magnet disk at the end of the motor and the axial magnetic pole of the rotor.

8. A torque driving method for a disk-type permanent magnet magnetic field-modulating permanent magnet synchronous motor, based on the disk-type permanent magnet magnetic field-modulating permanent magnet synchronous motor according to any one of claims 1 to 7, characterized in that: The following steps are involved: The stator armature winding applies q-axis current to interact with the rotor main magnetic field to generate driving torque, and the amplitude of the motor main magnetic field is adjusted by adjusting the relative position angle between the permanent magnet on the permanent magnet disk at the rotor end and the axial magnetic pole of the motor rotor.

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