Self-orienting high power-to-weight ratio outer rotor electric propulsion vernier motor

Abstract

The application discloses a self-rotating high power-to-weight ratio outer rotor electric propulsion cursor motor, and relates to the technical field of permanent magnet synchronous motor and motor and steering device integration design. The application comprises an outer rotor, the inner part of the outer rotor is movably connected with an inner stator assembly, the inner stator assembly is divided into multiple sections along the axial direction, and an armature winding is installed on each section of the inner stator assembly; a permanent magnet assembly is installed in the inner part of the outer rotor, is located between the outer rotor and the inner stator, and is divided into multiple sections along the axial direction; and a shell is fixedly connected with the yoke of the outer rotor, and the outer surface of the shell is provided with propeller blades. The application solves the problems of the prior art, such as the need of external steering device for single rotating motor, low power-to-weight ratio, heavy overall weight, and the like, and the outer rotor can simultaneously perform self-rotation and deflection movement, so that the steering device and the overall volume and weight can be reduced, mechanical loss can be reduced, and torque density can be increased.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet synchronous motors and integrated design technology of motors and steering systems, specifically to a self-steering high power-to-weight ratio external rotor electric propulsion vernier motor. Background Technology

[0002] Permanent magnet vernier motors are designed based on magnetic field modulation methods. Due to the unequal number of pole pairs between the stator and rotor, from an external characteristic perspective, they are equivalent to a regular permanent magnet motor with a mechanical reducer. They can achieve self-deceleration and torque increase within a limited space and can be widely used in electric propulsion systems. However, in traditional electric propulsion systems, a standalone rotating motor cannot perform steering motion, requiring an additional steering device. This is especially problematic for electric aircraft, which require lightweight propulsion systems, resulting in wasted space resources and increased overall weight. While traditional multi-degree-of-freedom motors can achieve both rotation and yaw motion, their structure has significant limitations, resulting in lower torque and difficulty meeting the requirements for high power-to-weight ratio. Furthermore, the use of a single armature winding acting on the same permanent magnet for both motions makes control and positioning difficult, and their performance is insufficient to meet current demands. Therefore, reducing size and weight and improving the power-to-weight ratio are critical issues that urgently need to be addressed to meet the requirements of electric propulsion systems. Summary of the Invention

[0003] The purpose of this invention is to provide a self-steering, high power-to-weight ratio external rotor electric propulsion vernier motor, which aims to reduce the size and weight of existing motors, improve the power-to-weight ratio, and meet the requirements of electric propulsion systems.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a self-steering high power-to-weight ratio external rotor electric propulsion vernier motor, comprising: an external rotor, wherein an inner stator assembly is movably connected inside the external rotor, the inner stator assembly being divided into multiple segments along the axial direction, and an armature winding is installed on each segment of the inner stator assembly; a permanent magnet assembly, wherein the permanent magnet assembly is installed inside the external rotor, located between the external rotor and the inner stator, and the permanent magnet assembly is divided into multiple segments along the axial direction; and a housing, wherein the housing is fixedly connected to the yoke of the external rotor, and propeller blades are installed on the outer surface of the housing.

[0005] Furthermore, the stator assembly is divided into three sections along the axial direction, including a first stator, a second stator, and a third stator. The first stator and the third stator are arranged along the axial direction, while the second stator is arranged radially. The first stator, the second stator, and the third stator are all provided with stator slots and stator teeth.

[0006] Furthermore, the stator teeth and stator slots of the first and third stators are axial and offset by 180° potential angles, while the stator teeth and stator slots of the second stator are radial and offset by 90° potential angles from the center lines of the stator teeth of the first and third stators, i.e., the armature windings are offset by 180° potential angles.

[0007] Furthermore, the armature winding of the second stator is a double three-phase winding, which is supplied with alternating current; the armature windings of the first and third stators are specifically six sets of single-phase windings, which are supplied with direct current, and the armature windings do not interfere with each other.

[0008] Furthermore, the permanent magnet assembly is divided into three sections along the axial direction, including a first permanent magnet, a second permanent magnet, and a third permanent magnet. The first, second, and third permanent magnets are all NS-type alternating tangential magnetization structures, and they are all fan-shaped rings that are wider at the top and narrower at the bottom. Magnetic isolation blocks are provided between the first, second, and third permanent magnets.

[0009] Furthermore, the number of pole pairs of the second permanent magnet is not equal to the number of pole pairs of the second stator armature winding, while the number of pole pairs of the first permanent magnet and the third permanent magnet are equal to the number of pole pairs of the first stator and the third stator, respectively.

[0010] Furthermore, the stator assembly is divided into three sections along the axial direction, including a first stator, a second stator, and a third stator. The first stator, the second stator, and the third stator are all arranged radially. The armature windings of the first stator and the third stator are ring-shaped, and the first stator and the third stator are offset by a potential angle of 180°, that is, the armature windings are offset by a potential angle of 180°.

[0011] Furthermore, the permanent magnet assembly is divided into three sections along the axial direction, including a first permanent magnet, a second permanent magnet, and a third permanent magnet. The first and third permanent magnets are both NS-type alternating surface-mount radial magnetization structures, and the second permanent magnet is an NS-type alternating tangential magnetization structure.

[0012] Furthermore, a connecting bridge is installed on the outer rotor yoke on the outer side of the second permanent magnet, and a magnetic shielding block is installed on the bottom of the second permanent magnet.

[0013] Furthermore, the stator assembly is divided into two sections along the axial direction, including a first stator and a second stator. The first stator is arranged along the axial direction, and the second stator is arranged along the radial direction. A spherical permanent magnet is installed on the inner side of the outer rotor corresponding to the first stator, and the spherical permanent magnet is surface-mounted radially magnetized.

[0014] This invention has at least the following beneficial effects:

[0015] (1) This invention utilizes the segmented stator and permanent magnet segmentation to realize the self-rotation and deflection of the motor respectively, and the armature windings do not interfere with each other, enabling efficient and precise coordinated control.

[0016] (2) Since the number of permanent magnet pole pairs is much greater than the number of armature winding pole pairs, it can achieve the effect of self-deceleration and torque increase, so its self-rotation torque is higher than that of other multi-degree-of-freedom motors.

[0017] (3) The stator teeth of the second stator radial direction adopt an unequal radius design in the axial direction, and the air gap size is equal to that of the second permanent magnet in space, which facilitates smooth switching between different deflection conditions.

[0018] (4) The second permanent magnet adopts a fan-shaped ring, which is wider at the top and narrower at the bottom. The magnetization direction is tangential, which has a better magnetization effect. In addition, the shape of the permanent magnet, which is wider at the top and narrower at the bottom, ensures that the magnetic field is symmetrical when the rotor deflects, resulting in smaller torque fluctuation.

[0019] (5) The first permanent magnet and the third permanent magnet are symmetrical to each other and also adopt the structure of a fan-shaped ring. The device is deflected only by the magnetic field of the two axially arranged stator armature windings. The upper and lower structures are symmetrical and the magnetic field is also symmetrical, which not only increases the deflection torque but also reduces torque fluctuation and makes the positioning more accurate.

[0020] (6) Since the outer rotor can deflect, the mechanical steering device of the drive system is eliminated, the overall mechanical loss is reduced, the weight of the drive system is reduced, the size of the device is reduced, and the power-to-weight ratio is increased.

[0021] (7) A connecting bridge and a magnetic blocking block were added to the outer rotor yoke, which not only eliminated the magnetic flux barrier effect of the vernier motor and ensured the main magnetic flux with a low number of pole pairs, but also eliminated the leakage magnetic flux of the permanent magnet and improved the torque density.

[0022] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of the overall internal structure of the present invention;

[0024] Figure 2 This is an exploded view of the overall structure of the present invention;

[0025] Figure 3 This is a schematic diagram of the rotating part of the present invention;

[0026] Figure 4 This is a schematic diagram of the deflection portion of the present invention;

[0027] Figure 5 This is a schematic diagram of the deflection angle limit of the present invention;

[0028] Figure 6 This is a schematic diagram of the external rotor structure with magnetic shielding block and connecting bridge of the present invention;

[0029] Figure 7 This is a schematic diagram of the stator assembly with annular windings according to the present invention;

[0030] Figure 8 This is a schematic diagram of the structure of the spherical cap-shaped permanent magnet of the present invention.

[0031] Figure label:

[0032] 1. External rotor; 2. Stator assembly; 2-1. First stator; 2-2. Second stator; 2-3. Third stator; 3. Permanent magnet assembly; 3-1. First permanent magnet; 3-2. Second permanent magnet; 3-3. Third permanent magnet; 3-4. Spherical cap permanent magnet; 4. Armature winding; 4-1. Radial armature winding; 4-2. Axial armature winding; 4-3. Annular winding; 5. Magnetic shielding block; 6. Housing; 7. Propeller blade; 8. Connecting bridge. Detailed Implementation

[0033] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0034] Example 1:

[0035] like Figure 1-5As shown, the present invention provides a self-steering high power-to-weight ratio external rotor electric propulsion vernier motor, including an external rotor 1. The external rotor 1 has an internally connected inner stator assembly 2. The inner stator assembly 2 is divided into three axial sections, including a first stator 2-1, a second stator 2-2, and a third stator 2-3. The first stator 2-1 and the third stator 2-3 are both axially arranged and are axial stators. The second stator 2-2 is radially arranged and is a radial stator. Stator slots and stator teeth are provided on the first stator 2-1, the second stator 2-2, and the third stator 2-3. The stator teeth of the first stator 2-1 and the third stator 2-3... All stator slots are axial and staggered by a potential angle of 180°. The stator teeth and stator slots of the second stator 2-2 are radial and staggered by a potential angle of 90° from the first stator 2-1 and the third stator 2-3. Each segment of the stator assembly 2 is equipped with an armature winding 4, which includes an axial armature winding 4-2 and a radial armature winding 4-1. The first stator 2-1 and the third stator 2-3 are equipped with axial armature windings 4-2, specifically six sets of unidirectional windings, which are energized with direct current. The second stator 2-2 is equipped with radial armature windings 4-1, specifically double three-phase windings, which are energized with alternating current. The armature windings 4 do not interfere with each other.

[0036] The permanent magnet assembly 3 is divided into three sections along the axial direction, including a first permanent magnet 3-1, a second permanent magnet 3-2, and a third permanent magnet 3-3. The first permanent magnet 3-1, the second permanent magnet 3-2, and the third permanent magnet 3-3 are all NS-type alternating tangential magnetization structures. A magnetic isolation block 5 is provided between the first permanent magnet 3-1, the second permanent magnet 3-2, and the third permanent magnet 3-3 to avoid magnetic flux interference. The number of pole pairs of the second permanent magnet 3-2 is not equal to the number of pole pairs of the armature winding 4 on the second stator 2-2. The number of pole pairs of the first permanent magnet 3-1 and the third permanent magnet 3-3 are equal to the number of pole pairs of the first stator 2-1 and the third stator 2-3, respectively.

[0037] The outer casing is fixedly connected to the yoke of the outer rotor 1. Since it is an outer rotor 1 motor, it can be used as a frameless rotor. Therefore, the outer surface of the outer casing is directly mounted with propeller blades, eliminating mechanical connection devices such as bearings and reducing mechanical losses.

[0038] This embodiment includes a deflection magnetic field and a rotation magnetic field, which are separated to prevent interference between them, thus improving the reliability of the motor. The magnetic flux in the rotation magnetic field is generated solely by the interaction between the radial armature winding 4-1 and the second permanent magnet 3-2. The radially arranged rotor teeth employ an unequal axial radius design, and the first permanent magnet 3-1, the second permanent magnet 3-2, and the third permanent magnet 3-3 are all fan-shaped rings, wider at the top and narrower at the bottom. When the rotor deflects, their rotation magnetic fields are symmetrical, allowing for smooth switching between different deflection conditions and reducing rotation torque fluctuations.

[0039] In the rotating magnetic field, the permanent magnet assembly 3 is magnetized tangentially, resulting in better magnetization. Furthermore, to increase the rotational torque, a magnetic field modulation principle is employed. By adding adjusting poles, the number of pole pairs is modulated, thereby achieving the effect of deceleration and torque increase. The principle is as follows:

[0040] If the radial stator tooth count is P s The number of pole pairs of radial armature winding 4-1 is P. a Then the number of pole pairs P of the second permanent magnet 3-2 r Should meet:

[0041] P r =|P s ±P a |

[0042] Therefore, the expression for the average torque of this rotation can be written as:

[0043]

[0044] In the formula r g It is the air gap length; l s It is the axial length; N s It is the number of turns in the winding; I max It is electric current; F c It is magnetically driven; k w Λ1 is the winding coefficient; Λ1 is the air gap reluctance. Therefore, the self-rotation torque of the structure of this invention is improved compared with the torque of existing multi-degree-of-freedom motors.

[0045] The magnetic flux of the deflection magnetic field is generated solely by the interaction between the axial armature winding 4-2 and the first permanent magnet 3-1 and the third permanent magnet 3-3. The first permanent magnet 3-1 and the third permanent magnet 3-3 are symmetrical to each other and also adopt a fan-shaped ring structure. Direct current is passed through the axial armature winding 4-24 to achieve the effect of deflecting the outer rotor 1. The direct current is continuously supplied to fix it in this position. By utilizing this symmetrical structure, the magnetic field is also symmetrical, which not only increases the deflection torque of the outer rotor 1 but also reduces torque fluctuation and makes the positioning more accurate.

[0046] In this embodiment, the rotation and deflection of the motor are combined to replace the drive motor and its steering device in the electric drive system, thereby reducing the mechanical loss of the overall mechanism, reducing the volume and weight of the overall drive system, and increasing the torque density of the motor.

[0047] Example 2:

[0048] like Figure 6As shown, the placement of the second permanent magnet 3-2 and the outer rotor 1 has been changed. Due to the magnetic flux barrier effect in the rotation magnetic field, the main magnetic flux with a low pole pair number is forced into the air gap when passing through the reverse-excited permanent magnet, resulting in an increase in magnetic circuit reluctance and a decrease in torque density. Therefore, a connecting bridge 8 is installed on the yoke of the outer rotor 1 to provide a magnetic flux path for the working subharmonic on the outside of the tangentially excited permanent magnet. Furthermore, a magnetic isolation block 5 is installed on the outside of the second permanent magnet 3-2 to prevent self-leakage. This embodiment utilizes the weakening of the magnetic flux barrier effect and self-leakage to improve torque density.

[0049] Example 3:

[0050] like Figure 7 As shown, the first stator 2-1 and the third stator 2-3 are designed as closed-slot annular stators with an outer diameter smaller than that of the second stator 2-2. The outer surfaces of the first stator 2-1, the second stator 2-2, and the third stator 2-3 are generally spherical, and the air gap between the stator assembly 2, the outer rotor 1, and the permanent magnet assembly 3 is consistent, which ensures that the magnetic flux remains consistent during rotation or deflection, reducing the difficulty of coordinated control. The armature winding 4 installed in the first stator 2-1 and the third stator 2-3 adopts an annular winding 4-3 structure. When alternating current is applied, the magnetic field at the annular winding 4-3 is changed, and it interacts with the first permanent magnet 3-1 and the third permanent magnet 3-3 to generate a deflection magnetic field. Since the end of the annular winding 4-3 is relatively short, the space utilization rate is high, and its deflection angle can be increased.

[0051] Example 4:

[0052] like Figure 8 As shown, the stator assembly 2 is divided into two sections along the axial direction, including a first stator 2-1 and a second stator 2-2. The first stator 2-1 is arranged along the axial direction, and the second stator 2-2 is arranged radially. The magnetic flux in the rotation magnetic field is generated only by the interaction between the radial armature winding 4-14 and the second permanent magnet 3-2. A spherical cap-shaped permanent magnet 3-4 is installed on the top inner side of the outer rotor 1. The spherical cap-shaped permanent magnet 3-4 is surface-mounted radially magnetized. The deflection magnetic field is generated by the interaction between the axial armature winding 4-2 and the spherical cap-shaped permanent magnet 3-4. The deflection angle is directly related to the diameter of the spherical cap-shaped permanent magnet 3-4. This method not only reduces the overall weight and improves the power-to-weight ratio of the embodiment, but also allows for free selection of the diameter of the spherical cap-shaped permanent magnet 3-4 to select the deflection angle, which is more convenient.

[0053] In summary, the self-rotating high power-to-weight ratio external rotor electric propulsion vernier motor of the present invention solves the problems of existing single rotating motors requiring external steering devices, low power-to-weight ratio, and heavy overall mass. Furthermore, the external rotor 1 can simultaneously perform self-rotation and yaw motion, which can reduce steering transposition and overall volume and weight, reduce mechanical losses, and increase torque density.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0055] For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on," "mounted on," "fixed to," or "set on" another element, it may be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A self-steering, high power-to-weight ratio external rotor electric propulsion vernier motor, characterized in that, include: An outer rotor (1) is movably connected to an inner stator assembly (2). The inner stator assembly (2) is divided into multiple segments along the axial direction, and each segment of the inner stator assembly (2) is equipped with an armature winding (4). Permanent magnet assembly (3), the permanent magnet assembly (3) is installed inside the outer rotor (1), it is located between the outer rotor (1) and the inner stator, and the permanent magnet assembly (3) is divided into multiple segments along the axial direction; The outer casing is fixedly connected to the yoke of the outer rotor (1), and propeller blades (7) are mounted on the outer surface of the outer casing. The stator assembly (2) is divided into three sections along the axial direction, including a first stator (2-1), a second stator (2-2), and a third stator (2-3). The first stator (2-1) and the third stator (2-3) are arranged along the axial direction, and the second stator (2-2) is arranged along the radial direction. The first stator (2-1), the second stator (2-2), and the third stator (2-3) are all provided with stator slots and stator teeth. The stator teeth and stator slots of the first stator (2-1) and the third stator (2-3) are axial and offset by 180° potential angle. The stator teeth and stator slots of the second stator (2-2) are radial and offset by 90° potential angle from the center line of the stator teeth of the first stator (2-1) and the third stator (2-3), that is, the armature winding (4) is offset by 180° potential angle.

2. The self-steering high power-to-weight ratio external rotor electric propulsion vernier motor according to claim 1, characterized in that: The armature winding (4) used in the second stator (2-2) is a radial armature winding (4-1), specifically a double three-phase winding, which is energized by alternating current; the armature winding (4) used in the first stator (2-1) and the third stator (2-3) is an axial armature winding (4-2), specifically a six-group single-phase winding, which is energized by direct current, and the armature windings (4) do not interfere with each other.

3. A self-steering high power-to-weight ratio external rotor electric propulsion vernier motor according to claim 2, characterized in that: The permanent magnet assembly (3) is divided into three sections along the axial direction, including a first permanent magnet (3-1), a second permanent magnet (3-2), and a third permanent magnet (3-3). The first permanent magnet (3-1), the second permanent magnet (3-2), and the third permanent magnet (3-3) are all NS-type alternating tangential magnetization structures, and they are all fan-shaped rings that are wider at the top and narrower at the bottom. A magnetic isolation block (5) is provided between the first permanent magnet (3-1), the second permanent magnet (3-2), and the third permanent magnet (3-3).

4. A self-steering high power-to-weight ratio external rotor electric propulsion vernier motor according to claim 3, characterized in that: The number of pole pairs of the second permanent magnet (3-2) is not equal to the number of pole pairs of the armature winding (4) of the second stator (2-2), while the number of pole pairs of the first permanent magnet (3-1) and the third permanent magnet (3-3) are equal to the number of pole pairs of the first stator (2-1) and the third stator (2-3), respectively.

5. A self-steering high power-to-weight ratio external rotor electric propulsion vernier motor according to claim 1, characterized in that: The stator assembly (2) is divided into three sections along the axial direction, including a first stator (2-1), a second stator (2-2), and a third stator (2-3). The first stator (2-1), the second stator (2-2), and the third stator (2-3) are all arranged radially. The armature windings (4) used in the first stator (2-1) and the third stator (2-3) are ring structures, and the first stator (2-1) and the third stator (2-3) are offset by a potential angle of 180°, that is, the armature windings (4) are offset by a potential angle of 180°.

6. A self-steering high power-to-weight ratio external rotor electric propulsion vernier motor according to claim 5, characterized in that: The permanent magnet assembly (3) is divided into three sections along the axial direction, including a first permanent magnet (3-1), a second permanent magnet (3-2) and a third permanent magnet (3-3). The first permanent magnet (3-1) and the third permanent magnet (3-3) are both NS-type alternating surface-mount radial magnetization structures, and the second permanent magnet (3-2) is an NS-type alternating tangential magnetization structure.

7. A self-steering high power-to-weight ratio external rotor (1) electric propulsion vernier motor according to claim 6, characterized in that: A connecting bridge (8) is installed on the yoke of the outer rotor (1) on the outside of the second permanent magnet (3-2), and a magnetic shielding block (5) is installed on the bottom of the second permanent magnet (3-2).

8. A self-steering high power-to-weight ratio external rotor electric propulsion vernier motor according to claim 1, characterized in that: The stator assembly (2) is divided into two sections along the axial direction, including a first stator (2-1) and a second stator (2-2). The first stator (2-1) is arranged along the axial direction, and the second stator (2-2) is arranged along the radial direction. A spherical permanent magnet (3-4) is installed on the inner side of the outer rotor (1) corresponding to the first stator (2-1), and the spherical permanent magnet (3-4) is surface-mounted radially magnetized.

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