CN114825725B - Low-cost axial permanent magnet motor and control system thereof - Google Patents

Abstract

The application provides a low-cost axial permanent magnet motor and control system thereof relates to motor technical field, and this permanent magnet motor includes: the rotating shaft, two rotors arranged on the rotating shaft and a stator positioned between the two rotors; the rotor comprises an end disc, a permanent magnet and a magnetic resistance, wherein the permanent magnet and the magnetic resistance have the same structure and size and are symmetrically arranged on the surface of the end disc to form a surface-mounted rotor; the magnetic poles of two adjacent permanent magnets are opposite and symmetrical about the center of the rotating shaft. The structure replaces the traditional N-S symmetrical arrangement mode of magnetic poles, replaces permanent magnets with magnetic resistance, reduces cost, is similar and symmetrical on a magnetic circuit, fully utilizes magnetic resistance torque generated by the magnetic resistance, remarkably improves torque density under the condition of unit permanent magnet consumption, and ensures that the maximum values of the permanent magnet torque and the magnetic resistance rotor of the motor can be overlapped at the same current phase angle by the magnetic resistance and the mirror image phase of the permanent magnet, thereby realizing the overlapped utilization of the permanent magnet torque and the magnetic resistance torque, and improving the torque density of the motor.

Description

A low-cost axial permanent magnet motor and its control system

Technical field

This application belongs to the field of motor technology, and in particular relates to a low-cost axial permanent magnet motor and its control system.

Background technique

The statements in this section merely provide background technical information related to this application and do not necessarily constitute prior art.

In recent years, with the widespread application of rare earth permanent magnet materials in motors, electromagnets in electrically excited synchronous motors have been gradually replaced by permanent magnet materials. Compared with traditional induction motors, permanent magnet synchronous motors have the advantages of small size, light weight, high power density, high torque density, high power factor, and high efficiency.

As a type of permanent magnet motor, axial permanent magnet motor, also called disc permanent magnet motor, has attracted more and more attention due to its compact structure, high efficiency, high power density and other advantages. In recent years, the topology of axial permanent magnet motors has been widely studied to improve torque density, with most studies focusing on five parts: stator/rotor combination, rotor core, PM arrangement, stator core and coil layout. Compared with radial flux motors, axial flux motors have a higher diameter-to-length ratio (compactness) and torque-to-weight ratio (torque density), so they have a wide range of application prospects. However, due to limitations in the motor manufacturing process, permanent magnet material properties, winding configuration technology, driver capacity, etc., axial magnetic field permanent magnet synchronous motors have not been effectively developed.

Contents of the invention

In order to solve the above problems, this application provides a low-cost axial permanent magnet motor and its control system, which not only has lower cost but also has higher torque density and operating efficiency, so that it is suitable for operating conditions.

In order to achieve the above objectives, the technical solutions adopted in this application are as follows:

In a first aspect, embodiments of the present application provide a low-cost axial permanent magnet motor, including: a rotating shaft, two rotors arranged on the rotating shaft, and a stator located between the two rotors; the rotor includes an end plate, a permanent magnet Magnets and reluctance, the permanent magnets and reluctance have the same structure and size, and are symmetrically arranged on the surface of the end plate to form a surface-mounted rotor; the magnetic poles of two adjacent permanent magnets are opposite and symmetrical about the center of the rotation axis.

As an optional implementation, the permanent magnet has a double sinusoidal structure, which is cut by double sinusoids with unequal amplitudes, and the magnetic resistance is structurally corresponding to the permanent magnet;

Alternatively, the magnetic resistance may be made of materials with the same or almost the same density as the permanent magnet.

As an optional embodiment, the stator includes a stator core and a stator winding. The stator winding is a two-phase winding and is evenly wound along the vertical direction of the circumference of the stator core.

As an optional embodiment, the stator core is an annular sleeve-shaped hollow core and does not include stator teeth or their corresponding slots.

As an optional implementation, the stator core is made of soft magnetic composite materials axially laminated.

As an optional implementation, multiple flat coils are spatially oriented around the stator, and four concentrated windings correspond to the two-phase windings and surround the stator core.

As an optional implementation, the two-phase windings are arranged symmetrically at 180 degrees in space, and one phase leads the other phase by 90 degrees in electromagnetic phase, forming the electromagnetic phase relationship of the motor.

As an optional embodiment, the rotor further includes a rotor sheath, which is tightly attached to the surface of the end disk and in close contact with the permanent magnet and magnetic resistance, and its outer diameter is the same as the end disk.

As an optional implementation, the rotor includes an N-pole permanent magnet reluctance auxiliary rotor and an S-pole permanent magnet reluctance auxiliary rotor; the air gap length between the N-pole permanent magnet reluctance auxiliary rotor and the stator is equal to the The length of the air gap between the S-pole permanent magnet reluctance auxiliary rotor and stator.

In a second aspect, embodiments of the present application also provide a control system for a low-cost axial permanent magnet motor, including the low-cost axial permanent magnet motor as described in the first aspect and any optional implementation of the first aspect and Two-phase connection controller. The two-phase connection controller is used to realize AC and DC conversion of electromechanical energy and control the stator winding of the low-cost axial permanent magnet motor. The two-phase connection controller is a two-phase six-switch bridge circuit. .

The beneficial effects of this application are:

(1) The low-cost axial permanent magnet motor provided by this application has a structure that replaces the traditional N-S symmetrical arrangement of magnetic poles. The permanent magnets are replaced with reluctance to reduce costs. The magnetic circuit is similar and symmetrical, making full use of the reluctance generated by the reluctance. Reluctance torque significantly increases the torque density per unit of permanent magnet usage. The reluctance and permanent magnet mirrors echo so that the motor's permanent magnet torque and the maximum value of the reluctance rotor can be superimposed at the same current phase angle, achieving permanent magnet The superimposed utilization of torque and reluctance torque improves the torque density of the motor.

(2) The permanent magnets and reluctance of the axial permanent magnet motor are optimized and designed based on the sinusoidal curve. The permanent magnet adopts a double sinusoidal structure. The outer sinusoidal curve is defined as Asinθ, the inner sinusoidal curve is Bsinθ, and the magnetic pole area is: It is cut by double sinusoids with unequal amplitudes. The effective area of the magnetic pole magnetic field lines when the wire is cut always changes sinusoidally, achieving the sinusoidalization of the flux linkage and counter electromotive force. The sinusoidal air gap field distribution reduces eddy current losses and air gap magnetic field harmonics. Reduce torque ripple and vibration noise and improve operating efficiency. Correspondingly, the reluctance corresponds to the permanent magnet in structure, which can reduce the axial magnetic pulling force and the net axial force. The reluctance uses materials with a density similar to that of the permanent magnet, which can balance the rotational inertia of the rotor and reduce the radial force.

The double sinusoidal structure permanent magnet-reluctance structure is designed to facilitate processing and reduce costs. The permanent magnets correspond to the reluctance. The formed rotor magnetic circuit is similar and symmetrical. The introduction of the reluctance rotor relatively reduces the motor torque pulsation and improves the permanent magnet per unit volume. The torque that the magnet can output.

(3) The stator winding of the axial flux permanent magnet motor uses two-phase windings. The two-phase windings are concentrated and use flat copper wires with rectangular cross-sections to increase the effective area of the wires and air gaps. The end windings are short and copper It has low loss and simple structure, and the air gap magnetic field modulation is more concise and ideal.

(4) The stator winding of the axial flux permanent magnet motor is controlled by a two-phase connection controller. The switches controlled by the three-phase winding connection need to be controlled simultaneously. The third-phase independent switch shared by the two-phase connection controller windings can be independently controlled. control without interference from the first two-phase switches. When the overall winding wire resistance remains unchanged, each phase of the three-phase winding is allocated a rated current I, and the two-phase winding is allocated a rated current 1.5I per phase. The three-phase and two-phase concentrated windings produce the same average torque. In addition, the switching tube operating power requirements of the three-phase six-switch bridge are: The switching tube power requirements of the two-phase six-switch bridge:/> Two-phase controllers have lower requirements on power devices.

(5) The stator of the axial permanent magnet motor adopts a hollow stator, which reduces the use of stator materials, eliminates cogging torque, reduces axial magnetic force, and reduces stator core losses.

Description of the drawings

The description and drawings that constitute a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

Figure 1 is an exploded schematic diagram of the structure of a low-cost axial permanent magnet motor provided by an embodiment of the present invention;

Figure 2 is a schematic diagram of the stator structure and winding phase distribution provided by the embodiment of the present application;

Figure 3 is a 1/2 cross-sectional schematic diagram of the stator provided by the embodiment of the present application;

Figure 4 is a schematic diagram of the stator control circuit topology provided by the embodiment of the present application;

Figure 5 is a schematic structural diagram of the N-pole permanent magnet reluctance auxiliary rotor provided by the embodiment of the present application;

FIG. 6 is a schematic structural diagram of the S-pole permanent magnet reluctance auxiliary rotor provided by the embodiment of the present application.

Reference symbols: 1. S-pole permanent magnet reluctance auxiliary rotor; 1-1. S-pole double-sinusoidal structure permanent magnet; 1-2. S-pole double-sinusoidal structure reluctance; 1-3. S-pole permanent magnet reluctance auxiliary Rotor end plate; 1-4, S pole permanent magnet reluctance auxiliary rotor sheath; 2, N pole permanent magnet reluctance auxiliary rotor; 2-1, N pole double sine structure permanent magnet; 2-2, N pole double sine Structural reluctance; 2-3, N-pole permanent magnet reluctance auxiliary rotor end disk; 2-4, N-pole permanent magnet reluctance auxiliary rotor sheath; 3. Stator; 3-1, stator core; 3-2, stator Winding; 4. Shaft.

Detailed ways

The present application will be further described below in conjunction with the accompanying drawings and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meanings commonly understood by one of ordinary skill in the art to which this application belongs.

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 application. As used herein, the singular forms are also intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, it will be understood that when the terms "comprises" and/or "includes" are used in this specification, they indicate There are features, steps, operations, means, components and/or combinations thereof.

Based on this, this application provides a low-cost axial permanent magnet motor, which is not only low in cost but also has high operating efficiency and torque density, and is suitable for various operating conditions.

Please refer to Figure 1. Figure 1 is an exploded schematic diagram of the structure of a low-cost axial permanent magnet motor provided by an embodiment of the present invention. As shown in Figure 1, the low-cost axial permanent magnet motor includes: a rotating shaft 4, and a Two rotors on the rotating shaft 4 and a stator 3 located between the two rotors; the rotors include end disks, permanent magnets and reluctances, the permanent magnets and reluctances have the same structure and size, and are symmetrically arranged on A surface-mounted rotor is formed on the surface of the end disk; the magnetic poles of two adjacent permanent magnets are opposite and symmetrical about the center of the rotating shaft.

In the specific implementation, the two rotors are the S-pole permanent magnet reluctance auxiliary rotor 1 and the N-pole permanent magnet reluctance auxiliary rotor 2. The stator 3 is located between the S-pole permanent magnet reluctance auxiliary rotor 1 and the N-pole permanent magnet reluctance auxiliary rotor. between rotors 2. The rotor has an axial double-layer structure, including a rotating shaft 4, and rotor end disks 1-3, 2-3 fixed on the rotating shaft. The permanent magnets and reluctors have the same structure and size, and are symmetrically arranged on the surface of the end disks. Surface-mounted rotor; the magnetic poles of two adjacent permanent magnets are opposite and symmetrical about the center of the rotation axis.

This application reduces the cost by replacing the permanent magnets with reluctance. At the same time, the magnetic circuits are similar and symmetrical, making full use of the reluctance torque generated by the reluctance. The torque density, reluctance and permanent magnet image are significantly improved under the unit amount of permanent magnets. The mutual response enables the motor's permanent magnet torque and the maximum value of the reluctance rotor to be superimposed at the same current phase angle, realizing the superimposed utilization of the permanent magnet torque and the reluctance torque, thus improving the torque density of the motor.

In the embodiment of this application, as an optional embodiment, the permanent magnet has a double sinusoidal structure, and the magnetic resistance is structurally corresponding to the permanent magnet;

Alternatively, the magnetic resistance may be made of materials with the same or almost the same density as the permanent magnet.

In the specific implementation, the permanent magnet adopts a double sinusoidal structure. The outer sinusoidal curve is defined as Asinθ, the inner sinusoidal curve is Bsinθ, and the magnetic pole area is: The magnetic resistance corresponds to the permanent magnet in structure, and is cut by double sinusoids with unequal amplitudes. The effective area of the magnetic pole magnetic field lines cut by the wire always changes sinusoidally, realizing the sinusoidalization of the flux linkage and back electromotive force, and the sinusoidal air gap field distribution to reduce Eddy current loss reduces air gap magnetic field harmonics, reduces torque ripple and vibration noise, and improves operating efficiency. As shown in Figures 2 and 3, the S pole double sinusoidal structure permanent magnet 1-1, the S pole double sinusoidal structure magnetic resistance 1-2, the N pole double sinusoidal structure permanent magnet 2-1, the N pole double sinusoidal structure magnetic resistance 2-2 adopts a sinusoidal design based on a double sinusoidal structure and is closely attached to the surface of the corresponding S pole permanent magnet reluctance auxiliary rotor end disk 1-3 and N pole permanent magnet reluctance auxiliary rotor end disk 2-3. The double sinusoidal structure permanent magnet 1-1 is mirror symmetrical about the N pole double sinusoidal structure magnetic resistance 2-2, and the N pole double sinusoidal structure permanent magnet 2-1 is mirror symmetrical about the S pole double sinusoidal structure magnetic resistance 1-2.

In the embodiment of this application, as an optional embodiment, the stator includes a stator core and a stator winding, and the stator winding is a two-phase winding that is evenly wound along the vertical direction of the circumference of the stator core; optionally, the stator winding is a two-phase winding. The stator core is a ring sleeve-shaped hollow core that does not contain stator teeth or their corresponding slots. Optionally, the stator core is made of soft magnetic composite materials axially laminated; optionally, as an optional embodiment, multiple flat coils are spatially oriented around the stator, and four concentrated windings correspond to two-phase windings. Surrounding the stator core.

In a specific implementation, as shown in Figures 4 and 5, the stator 3 includes a hollow stator core 3-1 and a stator two-phase winding 3-2. The stator core 3-1 adopts a slotless stator structure and is made of soft magnetic composite The materials are axially laminated. The stator winding 3-2 is a two-phase winding, and flat windings are used to evenly wrap around the stator core 3-1 along the vertical direction of the circumference of the stator core 3-1. In the figure, "+" represents the incoming direction of each phase winding, "-" represents the outgoing direction of each phase winding, A and B respectively represent the two phases of stator winding 3-2, and each phase is separated by a mechanical angle of 90°. The distribution form of each phase of the stator winding 3-2 can be changed, and the distribution of each phase winding here is only used for illustration.

Here, the stator core is a circular sleeve-shaped hollow core, which does not contain stator teeth or their corresponding slots, that is, a slotless stator structure, which can eliminate cogging torque, thereby effectively reducing vibration noise; the stator winding uses two-phase windings, two The phase winding is concentrated and uses flat copper wires with a rectangular cross-section, which can increase the effective area between the wires and the air gap, and the air gap magnetic field modulation is more ideal. The stator winding uses flat windings to make the ends smaller, easy to manufacture and wind, and has good heat dissipation performance. In addition, it also has high stiffness, which reduces the vibration noise of the motor winding, thereby improving the overall performance of the motor. Optionally, the two-phase windings are arranged symmetrically at 180 degrees in space to form the electromagnetic phase relationship of the motor.

In the embodiment of the present application, as an optional embodiment, the rotor further includes a rotor sheath. The rotor sheath is closely attached to the surface of the end disk and in close contact with the permanent magnet and the reluctance. Its outer diameter is consistent with the end disk. The disks are the same.

In the specific implementation, the S pole double sinusoidal structure permanent magnet 1-1, the S pole double sinusoidal structure magnetic resistance 1-2, the N pole double sinusoidal structure permanent magnet 2-1, and the N pole double sinusoidal structure magnetic resistance 2-2 are fixed respectively. On the corresponding S pole permanent magnet reluctance auxiliary rotor sheath 1-4 and N pole permanent magnet reluctance auxiliary rotor sheath 2-4, and closely adhere to the corresponding S pole permanent magnet reluctance auxiliary rotor end disk 1-3, On the surface of the N-pole permanent magnet reluctance auxiliary rotor end disk 2-3, the S-pole double-sinusoidal structure permanent magnet 1-1 is mirror symmetrical about the N-pole double-sinusoidal structure reluctance 2-2, and the N-pole double-sinusoidal structure permanent magnet 2- 1 is mirror symmetrical about the S pole double sinusoidal structure magnetoresistance 1-2.

Here, the rotor sheath is installed on the remaining space on the rotor surface except for the permanent magnets after the shape is optimized. The structure is compact and does not affect the effective air gap length of the motor.

In the embodiment of this application, as an optional embodiment, the rotor includes an N-pole permanent magnet reluctance auxiliary rotor and an S-pole permanent magnet reluctance auxiliary rotor; the N-pole permanent magnet reluctance auxiliary rotor and the stator are The length of the air gap is equal to the length of the air gap between the S-pole permanent magnet reluctance auxiliary rotor and the stator.

The advantage of the above technical solution is that the permanent magnet is cut by double sinusoids with unequal amplitudes. The effective area of the magnetic pole magnetic field lines cut by the wire always changes sinusoidally. The double sinusoidal structure realizes the sinusoidalization of the flux linkage and counter electromotive force, reducing the harmonics of the air gap magnetic field. , reduce torque ripple and vibration noise, and improve operating efficiency. The reluctance double-sinusoidal structure design is structurally corresponding to the double-sinusoidal structure permanent magnet, which reduces the axial magnetic pull and net axial force. The reluctance uses materials with a density similar to that of the permanent magnets to balance the rotational inertia of the rotor and reduce the radial force. The permanent magnets are replaced with reluctance to reduce costs. The magnetic circuits are similar and symmetrical, making full use of the reluctance torque generated by the reluctance. The torque density is significantly increased per unit of permanent magnet usage. The reluctance and permanent magnet mirror images make the motor permanent. The maximum values of the magnetic torque and the reluctance rotor can be superimposed at the same current phase angle, realizing the superposition and utilization of the permanent magnet torque and the reluctance torque.

The embodiment of the present application uses an axial magnetic flux structure to make the axial effective air gap length adjustable and not affected by the permanent magnet sheath, compact in size and superior in heat dissipation performance; the stator adopts a slotless hollow stator structure to eliminate cogging torque and reduce cogging torque. Small vibration noise and increased power density; the stator winding improves heat dissipation performance and efficiency by using flat wire winding technology; the rotor permanent magnet and reluctance are designed through shape optimization to realize the sine of the flux linkage and back electromotive force, so that the motor has low harmonic distortion , low vibration and noise, high efficiency and other advantages.

Embodiments of the present application also provide a control system for a low-cost axial permanent magnet motor, including the above-mentioned low-cost axial permanent magnet motor and a two-phase connection controller. The two-phase connection controller is used to realize electromechanical energy AC-DC conversion. , controlling the stator winding of the low-cost axial permanent magnet motor, and the two-phase connection controller is a two-phase six-switch bridge circuit.

In practical implementation, an important advantage of the two-phase connection controller is that the requirements on the drive circuit are lower. The switches controlled by the three-phase winding connection need to be controlled simultaneously and cooperatively. The third-phase independent switch shared by the two-phase connected controller winding can be controlled independently without interference from the first two-phase switches. When the overall wire resistance remains unchanged, each phase of the three-phase winding is allocated a rated current I, and the two-phase winding is allocated a rated current 1.5I per phase. The three-phase and two-phase concentrated windings produce the same average torque. In addition, the switching tube operating power requirements of the three-phase six-switch bridge are: The switching tube power requirements of the two-phase six-switch bridge:/> Two-phase controllers have lower requirements on power devices. Here, the topology diagram of the stator control circuit is shown in Figure 6. The two-phase connection controller is a two-phase six-switch bridge circuit. This circuit is used to realize AC and DC conversion of electromechanical energy and control the stator winding of the low-cost axial permanent magnet motor. .

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. The program can be stored in a computer-readable storage medium. During execution, the process may include the processes of the embodiments of each of the above methods. The storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM) or a random access memory (Random Access Memory, RAM), etc.

The above descriptions are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the protection scope of this application.

Claims (9)

1. A low cost axial permanent magnet machine comprising: the rotating shaft, two rotors arranged on the rotating shaft and a stator positioned between the two rotors; the two rotors comprise end discs, permanent magnets and magnetic resistances; the two rotors are respectively an S-pole permanent magnet reluctance auxiliary rotor and an N-pole permanent magnet reluctance auxiliary rotor; the end disc is fixed on the rotating shaft; the permanent magnet and the magnetic resistance have the same structure and size and are symmetrically arranged on the surface of the end disc to form a surface-mounted rotor;

the permanent magnet has a double sine structure, and defines an outer sine curve asThe inner sinusoid is +.>The magnetic pole area is: />The magnetic resistance is structurally corresponding to the permanent magnet and is formed by cutting double sine unequal amplitude values, and the magnetic resistance is made of materials with the same or nearly the same density as the permanent magnet;

the S-pole double-sinusoidal structure permanent magnet is in mirror symmetry with the N-pole double-sinusoidal structure magnetic resistance, and the N-pole double-sinusoidal structure permanent magnet is in mirror symmetry with the S-pole double-sinusoidal structure magnetic resistance;

the magnetic poles of the S-pole double-sinusoidal structure permanent magnet are opposite to the magnetic poles of the N-pole double-sinusoidal structure permanent magnet, and the two permanent magnets are symmetrical about the center of the rotating shaft.

2. The low cost axial permanent magnet machine of claim 1, wherein the stator includes a stator core and stator windings, the stator windings being two-phase windings uniformly wound in a perpendicular direction along a circumference of the stator core.

3. The low cost axial permanent magnet machine of claim 2, wherein the stator core is a hollow core of toroidal sleeve shape, not containing stator teeth or their corresponding slots.

4. A low cost axial permanent magnet machine according to claim 3, wherein the stator core is formed by axially laminating soft magnetic composite material.

5. The low cost axial permanent magnet machine of claim 2, wherein the plurality of flat coils are spatially oriented around the stator, and four concentrated windings correspond to two phase windings and surround the stator core.

6. The low cost axial permanent magnet machine of claim 2 wherein the two phase windings are spatially 180 degrees symmetrically arranged, one phase of the electromagnetic phase leading the other phase by 90 degrees, to form the electromagnetic phase relationship of the machine.

7. The low cost axial permanent magnet machine of claim 1 wherein the rotor further comprises a rotor jacket that is snugly against the surface of the end disk and is in intimate contact with the permanent magnet, reluctance, and has the same outer diameter as the end disk.

8. The low cost axial permanent magnet machine of claim 1 wherein the rotor comprises an N-pole permanent magnet reluctance assist rotor and an S-pole permanent magnet reluctance assist rotor; the length of the air gap between the N-pole permanent magnet reluctance auxiliary rotor and the stator is equal to that of the air gap between the S-pole permanent magnet reluctance auxiliary rotor and the stator.

9. A control system of a low-cost axial permanent magnet motor, comprising the low-cost axial permanent magnet motor according to any one of claims 1-8 and a two-phase connection controller, wherein the two-phase connection controller is used for realizing alternating current-direct current conversion of electromechanical energy and controlling a stator winding of the low-cost axial permanent magnet motor, and the two-phase connection controller is a two-phase six-switch bridge circuit.