A magnetic field regulation type permanent magnet motor based on electrically controlled variable magnetic barrier

Abstract

The application discloses a magnetic field regulation type permanent magnet motor based on electrically controlled variable magnetic barrier, which is composed of a rotor, a stator and an electrically controlled variable magnetic barrier, the electrically controlled variable magnetic barrier is composed of a stator toothed shoe and an armature coil wound on the stator toothed shoe, the armature coil is connected with three-phase current, which causes the magnetic saturation of the stator toothed shoe made of silicon steel sheets, the magnetic circuit at the position is changed from a passage to a break, a magnetic barrier structure is formed, the magnetic conductive distribution of the stator toothed shoe is changed, and the regulation and control of the air gap magnetic field distribution are realized. The magnetic saturation degree of the electrically controlled variable magnetic barrier is adjusted by the three-phase current amplitude passed in the armature coil, the electromagnetic structure parameters of the stator toothed shoe are changed with the saturation degree of the mechanical structure, and the electrically controlled flexible regulation of the air gap magnetic density in the motor and the electromagnetic parameters of the stator toothed shoe can be realized. The motor has the characteristics of large output torque, small torque ripple and low loss, and is suitable for the application occasions of electric vehicles and industrial robot joint driving requirements of high motor output torque quality.

Description

Technical Field

[0001] This invention belongs to the field of motor design and manufacturing, and specifically relates to a magnetic field-controlled permanent magnet motor based on an electronically controlled variable magnetic barrier. Background Technology

[0002] After the armature magnetic field of a permanent magnet synchronous motor is coupled with the rotating magnetic field of the rotor permanent magnet excitation, it can output stable torque. It is a high-performance and highly reliable AC motor with advantages such as low manufacturing cost, high power factor and high torque density. It has become an important alternative to traditional electrically excited motors and is widely used in aerospace, space exploration and industrial production.

[0003] However, the air gap magnetic field of permanent magnet motors is difficult to adjust, and their speed range and constant power region are narrow, limiting their development in electric vehicles. To broaden the speed range of permanent magnet motors, scholars at home and abroad have proposed different types of permanent magnet motors, such as hybrid excitation motors, memory motors, magnetic field enhancement motors, and variable leakage magnet motors.

[0004] Researchers at Jiangsu University have proposed a "V"-shaped, leakage-controllable, built-in permanent magnet motor, evolved from the traditional "V"-shaped built-in permanent magnet motor. The leakage flux of a traditional "V"-shaped motor is divided into two types: end-to-end leakage flux and inter-pole leakage flux. The "V"-shaped, leakage-controllable, built-in permanent magnet motor completely eliminates end-to-end leakage flux by adding an air magnetic barrier at the positive d-axis position of the permanent magnet, and adds an elliptical magnetic barrier at the positive q-axis position to create a convergence region between the inter-pole leakage flux and the q-axis magnetic flux. When different q-axis currents are applied to the "V"-shaped, leakage-controllable, built-in permanent magnet motor, the magnetic reluctance of the convergence region changes, thereby altering the inter-pole leakage flux.

[0005] German electrical engineers have proposed a memory motor whose excitation losses are negligible due to the very short duration of the current pulses. The permanent magnets employ a trapezoidal structure with tangential magnetization, and each pair of permanent magnets is isolated by a non-magnetic material, reducing magnetic leakage inside the rotor and maximizing the magnetic flux in the air gap. This motor can repeatedly and reversibly magnetize the permanent magnets using d-axis current pulses.

[0006] To improve the magnetic field adjustment capability of axial magnetic field permanent magnet motors, American electrical engineers proposed an axial magnetic field hybrid excitation motor structure. This structure employs alternating magnetic poles, demonstrating that this type of motor indeed possesses strong air gap magnetic field adjustment capabilities. Shanghai University has conducted research on the electromagnetic design and weak magnetic performance analysis of doubly-fed axial magnetic field hybrid excitation motors. Both of these motor topologies belong to the rotor permanent magnet type, meaning the permanent magnets are located on the rotor. This type of motor is difficult to manufacture and requires reinforcement structures for the permanent magnets to meet high-speed requirements.

[0007] Existing DC-modulated magnetic motors have relatively low torque density, and current research mainly focuses on radial flux motors. On the other hand, axial magnetic field permanent magnet motors have a compact structure, high torque density, and more flexible stator-rotor coordination, making them valuable for both research and application. Summary of the Invention

[0008] To address the aforementioned issues, this invention discloses a magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier. By altering the stator tooth tip magnetic permeability distribution, the distribution of the air gap magnetic field is controlled. This motor can flexibly adjust the magnetic flux using a small adjustment current, concentrate the magnetic flux, and effectively reduce leakage flux. It features high permanent magnet utilization, large output torque, and high efficiency.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows: A magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier includes a rotor, a stator, an electrically controlled variable magnetic barrier structure, and an air gap. The rotor includes a shaft, a rotor core, and a permanent magnet. The stator includes a stator core, stator teeth, and an armature winding. The electrically controlled variable magnetic barrier structure includes stator teeth and an armature coil. The air gap includes all the air between the rotor and the stator.

[0010] Furthermore, in the electrically controlled variable magnetic barrier structure, the distributed three-phase coils pass through the air gap and the stator slots formed by two adjacent stator teeth and are wound on the stator tooth shoes. Under the action of the three-phase current in the armature coil, the part of the stator tooth shoes wound with the three-phase coils becomes locally saturated, and the magnetic circuit of the magnetically saturated part of the stator tooth shoes is broken, forming an electrically controlled magnetic barrier that is adjusted by the amplitude of the three-phase current. This can be approximated as the distance between the stator tooth shoes of the motor increasing, thereby reducing the back electromotive force of the motor and increasing the speed.

[0011] Furthermore, the electromagnetic structure width of the stator gear shoe is negatively correlated with the magnetic saturation degree of its mechanical structure. The amplitude of the three-phase current in the armature coil adjusts the electromagnetic structure parameters of the stator gear shoe to change the spatial harmonic distribution of the air gap magnetic field, thereby realizing flexible electronic control adjustment of the air gap magnetic flux density in the motor.

[0012] Furthermore, the armature windings of the electrically controlled variable magnetic barrier structure, which include distributed three-phase coils, can be replaced by centralized DC coils. DC current is applied to these DC coils to achieve stator gear magnetic saturation.

[0013] Furthermore, in the electrically controlled variable magnetic barrier structure, the armature coil distribution widths at the upper and lower ends of the stator tooth shoe are unequal, with the armature coil distribution width within the air gap being greater than that within the stator slot.

[0014] Furthermore, in the electrically controlled variable magnetic barrier structure, the minimum width of the stator tooth shoe that can be used as a magnetic barrier is 1 / 4 of the stator tooth shoe width, and the maximum width is the same as the stator tooth shoe width.

[0015] Furthermore, the electrically controlled variable magnetic barrier structure can be applied to the stator and rotor, to the core structure which is the same as the stator tooth shoe structure and has a position close to the air gap where the armature coil can be wound.

[0016] Furthermore, the electrically controlled variable magnetic barrier structure can be applied to devices based on the principle of electromagnetic induction, such as motors and relays.

[0017] Furthermore, the magnetic field-controlled permanent magnet motor adopts a fractional-slot concentrated winding.

[0018] The beneficial effects of this invention are:

[0019] (1) Flexibility: The electronically controlled variable magnetic barrier structure can control the stator tooth width of the motor by saturating part of the stator teeth, changing the distance between stator teeth, thereby changing the amplitude of the back electromotive force of the motor, and finally controlling the speed of the motor.

[0020] (2) High torque output capability and high stability: The electronically controlled variable magnetic barrier structure can control the magnetic permeability distribution of the stator gear without changing the motor structure, thereby achieving the effect of concentrating magnetic flux and reducing leakage magnetic flux, increasing the main magnetic flux, and enhancing the motor's torque output capability and stability.

[0021] (3) High applicability: The electronically controlled variable magnetic barrier structure can be applied to any iron core structure that is similar to the stator gear shoe structure and has an armature coil that can be wound around the air gap. Its structure is suitable for motors, relays and other equipment based on the principle of electromagnetic induction, and has a very broad industrial application prospect. Attached Figure Description

[0022] Figure 1 This is a schematic cross-sectional view of a magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier, provided in part of an embodiment of the present invention, along its axis. Figure 2 This is a schematic diagram of the radial cross-sectional structure of a magnetic field-controlled permanent magnet motor based on an electronically controlled variable magnetic barrier, provided in part of an embodiment of the present invention. Figure 3 This is a schematic diagram of the radial cross-sectional structure of a magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier, provided in part of the embodiments of the present invention. The coil in the electrically controlled variable magnetic barrier of the motor is composed of three single-turn three-phase armature coils arranged in a three-phase energized sequence.

[0023] List of identifiers in attached diagrams: 1-Rotor, 101-Shaft, 102-Rotor core, 103-Permanent magnet pole, 2-Stator, 201-Stator core, 202-Stator teeth, 203-Armature winding, 3-Electrically controlled variable magnetic barrier, 301-Stator tooth shoe, 302-Armature coil, 4-Air gap. Implementation

[0024] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0025] like Figure 1 and Figure 2 As shown, this invention discloses a magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier, comprising a rotor 1, a stator 2, an electrically controlled variable magnetic barrier 3, and an air gap 4. The rotor 1 includes a shaft 101, a rotor core 102, and a permanent magnet 103. The stator 2 includes a stator core 201, stator teeth 202, and an armature winding 203. The electrically controlled variable magnetic barrier 3 includes a stator tooth shoe 301 and an armature coil 302. The air gap 4 includes all the air between the rotor 1 and the stator 2.

[0026] This invention addresses the high-efficiency magnet regulation requirements of electric vehicle motors, proposing a permanent magnet synchronous motor with high efficiency, high permanent magnet utilization, and large output torque. The invention features a simple structure, using permanent magnets for excitation, eliminating the need for excitation current and excitation losses, resulting in high efficiency and power density. An electronically controlled variable magnetic barrier 3 is designed on the stator teeth 202. Under the influence of the three-phase current within the armature coil 302, this barrier alters the magnetic permeability distribution of the stator teeth, forming a magnetic barrier structure. This magnetic barrier structure reduces leakage flux in the teeth and concentrates magnetic flux, thus achieving high permanent magnet utilization. As the amplitude of the alternating current in the armature winding 203 and armature coil 302 increases, the motor output torque increases, the magnetic saturation of the electronically controlled variable magnetic barrier 3 increases, and the back electromotive force in the armature winding 203 decreases, maintaining stable motor power. Therefore, this motor exhibits a large output torque under stable power conditions.

[0027] like Figure 1 and Figure 2 As shown, the stator core and rotor core are made of silicon steel laminations or other magnetically conductive structures, using the same manufacturing process as ordinary motors. The stator core is made by stamping silicon steel sheets into fan-shaped laminations and stacking them on positioning ribs. The positioning ribs are welded to the frame ring plate via support plates, and the core is then pressed together into a single unit using upper and lower toothed pressure plates and tension bolts. The rotor core is made of silicon steel sheets stamped into a circular ring and directly mounted on the motor shaft.

[0028] like Figure 2 As shown, the stator tooth shoe 301 of this invention has a wider width than that of a conventional permanent magnet synchronous motor, and its function during motor operation is also different from that of a conventional motor. Two stator tooth shoes are wound around armature coils 302, forming an electrically controlled magnetic barrier that is adjusted by the amplitude of the three-phase current. The middle portion of the stator tooth shoe 301 is not wound with armature coils 302, similar to a conventional motor, resulting in low magnetic resistance and providing a magnetic circuit.

[0029] like Figure 2As shown, the spacing between adjacent stator teeth 301 in this invention is relatively small. When the motor is unloaded, the smaller spacing between the stator teeth 301 can reduce harmonic distortion in the air gap magnetic field, resulting in a high sinusoidal no-load back electromotive force waveform in the armature winding 203. When the motor is under load, three-phase current flows through the armature coil 302, changing the magnetic permeability distribution of the stator teeth. The reluctance of the electronically controlled variable magnetic barrier 3 increases, reducing the strong leakage flux caused by the excessively small spacing between the stator teeth 301.

[0030] The electrically controlled variable magnetic barrier 3 consists of a portion of the stator gear shoe 301 and an armature coil 302. The armature coil 302 passes through the air gap 4 and the stator slot formed by two adjacent stator teeth 202 and is wound around both ends of the stator gear shoe 301. Under the action of the alternating current in the armature coil 302, the stator gear shoe 301 experiences local magnetic saturation. The magnetic circuit of the saturated part of the stator gear shoe 301 is broken, forming an electrically controlled magnetic barrier that is adjusted by the amplitude of the alternating current. This changes the magnetic permeability distribution of the stator gear shoe 301 and regulates the spatial harmonic distribution of the air gap magnetic field in the motor.

[0031] like Figure 2 As shown, the width of the electromagnetic structure of the stator gear shoe 301 is negatively correlated with the magnetic saturation degree of its mechanical structure. By adjusting the amplitude of the alternating current in the armature coil 302, the electromagnetic structure of the stator gear shoe 301 is changed, thereby changing the spatial harmonic distribution of the air gap magnetic field and realizing flexible electronic control adjustment of the air gap magnetic flux density in the motor.

[0032] like Figure 2 As shown, the minimum width of the electrically controlled variable magnetic barrier 3 is 1 / 4 of the width of the stator gear shoe 301, and the maximum width is the same as the width of the stator gear shoe 301.

[0033] like Figure 2 As shown, the electrically controlled variable magnetic barrier 3 is suitable for motors and relays based on the principle of electromagnetic induction.

[0034] like Figure 2 As shown, the armature winding 302 containing distributed three-phase coils can be replaced by a DC coil, wherein a DC current is passed through the DC coil to achieve magnetic saturation of the magnetic barrier section.

[0035] A single-turn armature coil is tightly bonded to the stator tooth shoe 301, forming a variable magnetic barrier. The electrically controlled variable magnetic barrier is positioned near the air gap inside the motor. It can be integrated into the stator and rotor on a core structure with the same structure as the stator tooth shoe 3, which is located near the air gap and can be wound with the armature coil.

[0036] The width of the armature coil distribution within the air gap is greater than that of the armature coil distribution within the stator slot.

[0037] like Figure 2As shown, the armature winding 302 adopts a fractional-slot concentrated winding, which is wound around the stator teeth 202. In this embodiment, since the ends of the fractional-slot concentrated winding are shorter than those of the traditional distributed winding, the copper loss is low, which helps to reduce the temperature rise when the motor is under load.

[0038] like Figure 2 As shown, the rotor adopts an alternating N / S pole structure. Similarly, an alternating pole structure can also be used, utilizing the characteristic of a magnetic core that can converge magnetic lines of force to form magnetic poles. This allows for the replacement of some permanent magnet poles with iron core poles, creating a hybrid magnetic pole structure. The N pole uses neodymium iron boron material, while the S pole is entirely replaced by an iron core. By appropriately increasing the pole arc coefficient and magnet thickness of the permanent magnet poles, the motor using an alternating pole excitation structure can improve the utilization rate of permanent magnets, thereby increasing the motor's torque density and output capacity, and effectively reducing motor production costs.

[0039] like Figure 2 As shown, the electrically controlled variable magnetic barrier structure 3 proposed in this invention has a wide range of applications and is applicable to permanent magnet motors with various stator tooth shoe 301 shapes and structures. The stator tooth shoe protrudes laterally relative to the stator teeth to provide the iron core portion for winding the armature coil 302 as an electrically controlled variable magnetic barrier structure.

[0040] like Figure 2 As shown, the electrically controlled variable magnetic barrier structure 3 can be applied to the rotor part of the motor. When there is a rotor tooth shoe part in the rotor structure, the armature coil is wound on the protruding iron core, and this part can also be used as an electrically controlled variable magnetic barrier structure.

[0041] In the magnetic field-controlled permanent magnet motor based on electronically controlled variable magnetic barriers proposed in this invention, both the stator 201 and the rotor 102 are composed of silicon steel sheets stacked axially.

[0042] like Figure 2 As shown, the permanent magnet 103 on the rotor is made of high-performance permanent magnet materials such as neodymium iron boron.

[0043] like Figure 2 As shown, the magnetic field-controlled permanent magnet motor based on electronically controlled variable magnetic barriers has two operating states, which are determined by the energization status of the armature coil 302.

[0044] like Figure 3 As shown, the method of winding the armature coil 302 containing distributed three-phase coils on the stator gear shoe 301 is to uniformly wind three single-turn three-phase armature coils arranged in the energizing sequence from the end of the stator gear shoe inwards.

[0045] like Figure 2As shown, the stator tooth shoe 301 is extended laterally until it completely fits against the adjacent stator tooth shoe, fixing the length of the armature coil in the magnetic barrier section between the two stator teeth. The iron core portion around which the armature coil is wound is replaced with ferrite material. When the armature coil is not energized, an alternating pole structure is formed, which acts as a modulator, increasing the motor's output torque. When a three-phase current sufficient to saturate the ferrite is applied to the armature coil, the magnetic barrier section can be considered as air, increasing the motor's magnetic reluctance, decreasing the back electromotive force, and increasing the speed.

[0046] like Figure 2 As shown, the width of the armature coil distribution at both ends of the stator tooth shoe 301 depends on the shape of the stator tooth shoe, and the tilt angle of the upper or lower side of the stator tooth shoe is negatively correlated with the width of the armature coil distribution it is wound on.

[0047] like Figure 2 As shown, the stator tooth shoe 301 has a certain inclination angle on one side near the stator slot, and the thickness of the stator tooth shoe gradually decreases from the middle to both ends. Armature coils 302 are wound around the thinnest ends of the stator tooth shoe. On the one hand, this can save armature coils and reduce costs. On the other hand, the thinner ends of the stator tooth shoe are more likely to reach magnetic saturation as the three-phase current in the armature coil increases.

[0048] In the magnetic field-controlled permanent magnet motor based on electrically controlled variable magnetic barriers proposed in this example, when a sufficient AC current amplitude is applied, the stator tooth shoe 301 wound with the armature coil becomes partially saturated and can be considered as air. This increases the motor's magnetic reluctance, decreases the back electromotive force, and increases the rotational speed. Based on this characteristic, this motor can be applied to any application requiring high starting speeds, such as electric vehicles, impact drills, and electric mixers.

[0049] When no current flows through the armature coil 302, the magnetic field-controlled permanent magnet motor is a conventional permanent magnet motor. When current flows through the armature coil, the electromagnetic parameters of the stator gear 301 change with the current parameters. The magnetic field-controlled permanent magnet motor has the characteristics of large output torque, small torque ripple, and low loss, and is suitable for applications requiring high-quality motor output torque, such as electric vehicles and industrial robot joint drives.

[0050] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier, the motor comprising a rotor (1) and a stator (2), wherein, The rotor (1) includes a shaft (101), a rotor core (102), and a permanent magnet (103); the stator (2) includes a stator core (201), stator teeth (202), and an armature winding (203); characterized in that it further includes an electrically controlled variable magnetic barrier (3) and an air gap (4); the electrically controlled variable magnetic barrier (3) includes a stator tooth shoe (301) and an armature coil (302) containing distributed three-phase coils; the air gap (4) includes the rotor (1) and All the air between the stator (2); the armature coil (302) passes through the air gap (4) and the stator slot formed by two adjacent stator teeth (202) and is wound on the stator tooth shoe. A set of distributed three-phase coils is composed of three single-turn coils arranged in a three-phase energized sequence. The number of sets of the distributed three-phase coils on the stator tooth shoe is equal to the number of single-phase turns of the armature winding (203) in a single stator slot, so as to ensure that the magnetic saturation state of the stator tooth shoe does not change with the alternation of armature current; The working principle of an electric motor is: An electrically controlled variable magnetic barrier (3) structure is designed on the stator teeth (202). Under the action of the alternating current in the armature coil (302), the stator tooth shoe (301) becomes magnetically saturated, the magnetic circuit becomes open circuit, and a magnetic barrier structure is formed, which changes the magnetic permeability distribution of the stator tooth shoe and realizes the control of the spatial harmonic distribution of the air gap magnetic field. The magnetic barrier structure has the effect of concentrating magnetic flux on the one hand, and reduces the leakage magnetic flux of the stator tooth shoe on the other hand, so the permanent magnet utilization rate of the motor is high. As the amplitude of the alternating current in the armature winding (203) and the armature coil (302) increases, the output torque of the motor increases, the magnetic saturation degree of the electrically controlled variable magnetic barrier (3) increases, and the back electromotive force in the armature winding (203) decreases, so the motor power remains stable. Therefore, this motor has a large output torque under stable power.

2. The magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier according to claim 1, characterized in that: The minimum width of the electrically controlled variable magnetic barrier (3) is 1 / 4 of the width of the stator toothed shoe (301), and the maximum width of the electrically controlled variable magnetic barrier (3) is the width of the stator toothed shoe (301).

3. A magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier according to claim 1, characterized in that: An electrically controlled variable magnetic barrier is placed near the air gap of the motor and is integrated on the stator (2) and the rotor (1). The rotor (1) has a rotor toothed shoe portion with the same structure as the stator toothed shoe (301). The rotor toothed shoe portion is close to the air gap and is wound with the armature coil (302).

4. A magnetic field-controlled permanent magnet motor based on an electrically controlled variable magnetic barrier according to claim 1, characterized in that: The width of the armature coil (302) placed in the air gap is greater than the width of the armature coil placed in the stator slot.

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