Magnetic-adjustable back-wound motor structure

Abstract

The utility model belongs to the technical field of motors, and relates to a magnetic-adjustable back-wound motor structure, which comprises a stator iron core, the stator iron core comprises an annular stator yoke part, a plurality of stator inner teeth are uniformly distributed on the inner wall of the stator yoke part, and the outer surface of the stator yoke part is respectively provided with a stator outer tooth corresponding to each stator inner tooth; groove-shaped adjustable flux winding upper positioning grooves and adjustable flux winding lower positioning grooves are symmetrically formed in the two sides of the stator outer teeth, adjustable flux windings are wound on the adjustable flux winding upper positioning grooves and the adjustable flux winding lower positioning grooves of the stator outer teeth respectively, and the two sides of coils of the adjustable flux windings are located in the adjustable flux winding upper positioning grooves and the adjustable flux winding lower positioning grooves respectively. The turns of the windings on the two sides are equal; according to the utility model, by arranging the adjustable magnetic windings on the outer stator teeth, the magnetic field modulation effect generated after the adjustable magnetic windings are electrified is utilized to increase and demagnetize the internal magnetic field of the motor and adjust the air-gap magnetic field, thereby realizing transmission of large torque at a low speed or flux-weakening speed expansion at a high rotating speed.

Description

Technical Field

[0001] The utility model belongs to the technical field of motor equipment and relates to a magnetically adjustable back-wound motor structure. Background Art

[0002] With the advancement of industrial manufacturing and technology, the trend toward higher motor speeds is a key trend in motor technology. High-speed permanent magnet synchronous motors (PMSMs), due to their high efficiency, high power density, and high reliability, offer broad application prospects and market potential. Applications include electric vehicles, high-speed air compressors, high-speed grinding machines, wind turbines, and vacuum pumps. However, conventional PMSM rotors typically utilize high-coercivity permanent magnets such as neodymium iron boron (NdFeB) or samarium cobalt (SmCo). This makes the air gap magnetic field difficult to adjust, significantly limiting the speed regulation range.

[0003] There is a high-speed back-wound motor structure as shown in the following example: Figure 1 As shown, the rotor is typically a cylindrical permanent magnet with one or two pairs of poles. The stator core adopts a back-wound structure, with the windings wrapped entirely around the stator yoke, significantly reducing the end height. Motors with this structure are typically used in high-speed applications, with speeds exceeding 100,000 rpm. The air gap magnetic field, primarily provided by the permanent magnets, is difficult to adjust. The motor's back electromotive force is proportional to the speed, and the constant power speed range is limited. This can only be achieved by reducing the number of winding turns and increasing the number of windings, which increases the difficulty of motor manufacturing and restricts the further development of high-speed back-wound motor structures. Summary of the Invention

[0004] In response to the above-mentioned problems, the utility model provides a magnetically adjustable back-wound motor structure. By arranging a magnetically adjustable winding on the outer stator teeth, the magnetic field modulation effect generated by the magnetically adjustable winding after being energized is utilized to magnetize and demagnetize the internal magnetic field of the motor, thereby adjusting the air gap magnetic field and realizing the transmission of high torque at low speed or weak magnetic speed expansion at high speed.

[0005] According to the technical solution of the utility model: a magnetically adjustable back-wound motor structure includes a stator core, the stator core includes an annular stator yoke, the inner wall of the stator yoke is evenly provided with a plurality of stator internal teeth, and the outer surface of the stator yoke is respectively provided with a stator external tooth corresponding to each stator internal tooth; the characteristics are:

[0006] Grooved upper positioning grooves and lower positioning grooves for the magnetic tuning winding are symmetrically provided on both sides of the stator outer teeth. The magnetic tuning winding is wound on the upper positioning grooves and lower positioning grooves of the magnetic tuning winding of each stator outer tooth, and the two sides of the coil of the magnetic tuning winding are respectively located in the upper positioning grooves and lower positioning grooves of the magnetic tuning winding, and the number of turns of the windings on both sides is equal.

[0007] As a further improvement of the present invention, the radial inner end of each stator inner tooth is constructed with an arc-shaped extension portion, and the rotor permanent magnet is arranged in the space formed by the arc-shaped extension portions of several stator inner teeth.

[0008] As a further improvement of the present invention, a protective sleeve is provided on the rotor permanent magnet.

[0009] As a further improvement of the present invention, a main armature winding is wound on the stator yoke, and one side of the main armature winding is located in a stator inner slot surrounded by two adjacent stator inner teeth and the stator yoke;

[0010] The other side of the main armature winding is located in a stator outer slot surrounded by two adjacent stator outer teeth and a stator yoke.

[0011] As a further improvement of the present invention, center lines of a corresponding set of stator inner teeth and stator outer teeth are on the same straight line.

[0012] As a further improvement of the present invention, the width and depth of the upper positioning groove and the lower positioning groove of the magnetic tuning winding are determined by the size of the stator outer teeth and the size of the wound magnetic tuning winding.

[0013] The technical effects of this utility model are as follows: 1. Under constant voltage conditions, the magnetic modulation effect of the magnetic modulation winding can be utilized during motor design to appropriately increase the number of turns of the motor, reduce the number of parallel turns in the motor, and reduce the difficulty of motor winding, which is more conducive to the further development of motors in the direction of modular design. 2. The motor's magnetic weakening capability is improved, allowing the motor to obtain a wider speed adjustment range or ensure the output of motor speed and torque under low voltage conditions. 3. At low speeds, the magnetic modulation effect of the magnetic modulation winding is utilized to enhance the internal magnetic field of the motor and improve the output torque capacity of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an existing back-wound motor structure.

[0015] Figure 2 It is a structural diagram of the present utility model.

[0016] Figure 3 This is a schematic diagram of the weak magnetic working state of the utility model.

[0017] Figure 4 This is the magnetic potential vector diagram of the weak magnetic working state of the utility model.

[0018] Figure 5 This is a schematic diagram of the magnetization working state of the utility model.

[0019] Figure 6 This is the magnetic potential vector diagram of the magnetization working state of the utility model. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0021] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts should fall within the scope of protection of the present invention.

[0022] Figure 1-6 The stator comprises a stator core 1', a stator yoke 1, stator inner teeth 2, stator outer teeth 3, an upper positioning slot 4 for a magnetic tuning winding, a lower positioning slot 5 for a magnetic tuning winding, an outer tooth pole shoe 6, a stator inner slot 7, a stator outer slot 8, a main armature winding 9, a magnetic tuning winding 10, a rotor permanent magnet 11, and a sheath 12; A, X, B, Y, C, and Z are phase belts where the conductors in the stator winding slots are located.

[0023] like Figure 2-6 As shown, the utility model is a magnetically adjustable back-wound motor structure, comprising a stator core 1', wherein the stator core 1' comprises a ring-shaped stator yoke 1, a plurality of stator internal teeth 2 being evenly distributed on the inner wall of the stator yoke 1, and a stator external tooth 3 being respectively provided on the outer surface of the stator yoke 1 corresponding to each stator internal tooth 2.

[0024] Grooved upper positioning slots 4 and lower positioning slots 5 for the magnetic tuning winding are symmetrically provided on both sides of the stator outer teeth 3. A magnetic tuning winding 10 is wound on the upper positioning slots 4 and lower positioning slots 5 for the magnetic tuning winding of each stator outer tooth 3. The two sides of the coil of the magnetic tuning winding 10 are respectively located in the upper positioning slots 4 and lower positioning slots 5 for the magnetic tuning winding, and the number of turns of the windings on both sides is equal.

[0025] The radial inner end of each stator inner tooth 2 is respectively configured with an arc-shaped extension portion. The rotor permanent magnet 11 is arranged in the space surrounded by the arc-shaped extension portions of the stator inner teeth 2 , and the rotor permanent magnet 11 is sleeved with a sheath 12 .

[0026] A main armature winding 9 is wound on the stator yoke 1 , and one side of the main armature winding 9 is located in a stator inner slot 7 formed by two adjacent stator inner teeth 2 and the stator yoke 1 .

[0027] The other side of the main armature winding 9 is located in a stator outer slot 8 surrounded by two adjacent stator outer teeth 3 and the stator yoke 1 .

[0028] The center lines of a corresponding set of stator internal teeth 2 and stator external teeth 3 are on the same straight line.

[0029] The width and depth of the upper positioning groove 4 and the lower positioning groove 5 of the magnetic tuning winding are determined by the size of the stator external teeth 3 and the size of the wound magnetic tuning winding 10.

[0030] In actual operation, the field-tuning winding 10, in conjunction with the rotor permanent magnets 11 and the main armature winding 9, enables the motor to achieve three operating modes: 1) normal operating mode; 2) field-weakening operating mode; and 3) magnetization operating mode. In normal operating mode, the field-tuning winding 10 is deenergized and inactive. During this time, the rotor generates a constant magnetic field through the rotor permanent magnets 11. A three-phase symmetrical current flows through the main armature winding 9, generating a stator rotating magnetic field. When the frequency of the stator rotating magnetic field matches the frequency of the rotor magnetic field, the rotor rotates synchronously. Power transmission is achieved through the magnetic force between the magnetic field generated by the main armature winding 9 and the excitation field generated by the rotor permanent magnets 11.

[0031] When the motor is in the weakening and increasing magnetization working state, a DC current is passed through the magnetic field winding 10 to generate a magnetic field. The polarity of the magnetic field can be controlled by changing the direction of the current. The degree of magnetization or weakening is determined by the magnitude of the current. By adjusting the direction of the magnetic field generated by the magnetic field winding 10, the motor can achieve weakening and increasing magnetization. When the magnetic field is opposite to the magnetic field of the rotor permanent magnet 11, the motor is in the weakening working state. Figure 3 and Figure 4 When the magnetic field of the magnetizing motor is in the same direction as the magnetic field of the rotor permanent magnet 11, the motor is in the magnetizing working state, as shown in FIG. Figure 5 and Figure 6 The following is a detailed description of the working conditions shown in the weakening and increasing magnetization.

[0032] Figure 3 In the figure, two magnetic tuning windings 10 are drawn, corresponding to the N and S poles of the rotor, separated by 180°. The "+" represents the positive pole and the "-" represents the negative pole. The direction of the current in the magnetic tuning winding 10 flows from the "+" pole to the "-" pole. According to the right-hand rule, the magnetic field generated by the magnetic tuning winding 10 is as follows: Figure 3 The direction of the magnetic field formed by the magnetic field is opposite to the direction of the magnetic field of the excitation magnetic circuit formed by the rotor permanent magnet 11, thus weakening the excitation magnetic field. The degree of magnetic weakening is related to the current flowing through the field adjustment winding 10. The magnetic field generated by the field adjustment winding 10 and the permanent magnet 11 interacts with the magnetic field of the main armature winding 9 to generate the output torque of the motor. (In this embodiment, the main armature winding is the same as the Figure 2 , and at this position, the unenergized magnetic winding is not drawn).

[0033] like Figure 4 The figure shows the space vector diagram of magnetic potential in the weak magnetic working state, where F f Represents the permanent magnet excitation magnetic potential, F Trepresents the magnetic flux density generated by the magnetic flux density winding 10, F a Represents the armature reaction magnetic potential generated by the main armature winding 9. The direction of the magnetic potential generated by the magnetic modulation winding 10 is opposite to the direction of the excitation magnetic potential of the rotor permanent magnet 11, which plays a role of magnetic weakening, and F a Ahead of F f and F T At a certain angle, drag F f and F T The resultant magnetic potential rotates together, and the magnetic force between them provides dynamic torque for the rotor.

[0034] When the magnetomotive force generated by the three-phase symmetrical current in the main armature winding 9 rotates in a certain direction, such as counterclockwise, the rotor permanent magnet 11 also rotates synchronously, and the magnetic field adjustment windings 10 corresponding to the rotor N pole and S pole in the stator outer teeth 3 are also continuously turned on in the counterclockwise direction. In one state, the number of magnetic field adjustment windings 10 turned on is the same as the number of rotor poles. The current direction is controlled so that the magnetic field generated by the magnetic field adjustment windings 10 is opposite to the magnetic field of the rotor permanent magnet 11, and the other magnetic field adjustment windings 10 are turned off. Therefore, the above Figure 4 The space vector diagram in the figure also rotates counterclockwise. This working state is the field-weakening working state. Under the condition of a certain DC bus voltage, it can suppress the rise of back electromotive force, thereby playing the role of field-weakening speed regulation.

[0035] Similarly, Figure 5 This embodiment demonstrates the magnetizing operation of the field-tuning winding. The "+" and "-" poles of the field-tuning winding 10 are altered so that the magnetic field generated by the field-tuning winding 10 aligns with the excitation field generated by the rotor permanent magnets 11, thereby achieving a magnetizing effect. The combined magnetic field of the field-tuning winding 10 and the rotor permanent magnets 11 interacts with the magnetic field of the main armature winding 9 to generate motor torque.

[0036] like Figure 6 The figure shows the spatial vector diagram of the magnetic potential in the magnetizing state. The direction of the magnetic potential generated by the field-tuning winding 10 is the same as the excitation magnetic potential of the rotor permanent magnets 11, providing a magnetizing effect. This, combined with the armature reaction magnetic potential of the main armature winding 9, creates a combined magnetomotive force that generates the air gap flux density, which in turn outputs the motor torque. At low speeds and with sufficient power supply voltage, this operating state enhances the motor's internal magnetic field, thereby increasing the motor's torque and boosting its power / torque density.

[0037] In summary, ① no current flows through all the field-tuning windings 10, and the magnetizing or field-weakening functions are disabled. The motor is in normal operating mode. ② When the power supply voltage is insufficient to provide a higher speed, the magnetic field generated by the field-tuning windings 10 is opposite to the excitation field of the permanent magnets 11, and the magnetic field of the main armature windings is combined to suppress the rise of the back electromotive force, thus achieving a field-weakening speed-expanding effect. The motor is in field-weakening mode. ③ When the speed is low and high torque is required, current of opposite polarity can be passed through the field-tuning windings 10, so that the magnetic field generated by the field-tuning windings 10 is the same as the excitation field of the permanent magnets 11, and the magnetic field of the main armature windings is combined to increase the air gap magnetic field strength, thereby improving the torque and power density of the motor. The motor is in magnetizing mode.

[0038] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to examples, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A magnetically adjustable back-wound motor structure, comprising a stator core (1'), the stator core (1') comprising an annular stator yoke (1), a plurality of stator internal teeth (2) being evenly distributed on the inner wall of the stator yoke (1), and a stator external tooth (3) being respectively provided on the outer surface of the stator yoke (1) and corresponding to each stator internal tooth (2); characterized in that: Grooved upper magnetic tuning winding positioning grooves (4) and lower magnetic tuning winding positioning grooves (5) are symmetrically provided on both sides of the stator outer teeth (3); a magnetic tuning winding (10) is respectively wound on the upper magnetic tuning winding positioning grooves (4) and the lower magnetic tuning winding positioning grooves (5) of each stator outer tooth (3); both sides of the coil of the magnetic tuning winding (10) are respectively located in the upper magnetic tuning winding positioning grooves (4) and the lower magnetic tuning winding positioning grooves (5), and the number of turns of the windings on both sides is equal.

2. The magnetically adjustable back-wound motor structure according to claim 1, wherein: The radial inner end of each stator inner tooth (2) is respectively configured with an arc-shaped extension portion, and a rotor permanent magnet (11) is arranged in a space formed by the arc-shaped extension portions of a plurality of stator inner teeth (2).

3. The magnetically adjustable back-wound motor structure according to claim 2, wherein: A protective sleeve (12) is sleeved on the rotor permanent magnet (11).

4. The magnetically adjustable back-wound motor structure according to claim 1, wherein: A main armature winding (9) is wound on the stator yoke (1), and one side of the main armature winding (9) is located in a stator inner slot (7) surrounded by two adjacent stator inner teeth (2) and the stator yoke (1); The other side of the main armature winding (9) is located in a stator outer slot (8) surrounded by two adjacent stator outer teeth (3) and a stator yoke (1).

5. The magnetically adjustable back-wound motor structure according to claim 1, wherein: The center lines of a corresponding set of stator inner teeth (2) and stator outer teeth (3) are on the same straight line.

6. The magnetically adjustable back-wound motor structure according to claim 1, wherein: The width and depth of the upper positioning groove (4) and the lower positioning groove (5) of the magnetic adjustment winding are determined by the size of the stator outer teeth (3) and the size of the wound magnetic adjustment winding (10).

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