Integrated magnetic conductance modulation type high-torque-density permanent magnet torque motor

Abstract

The invention discloses an integrated magnetic conductance modulation type high-torque-density permanent magnet torque motor, which solves the problem that a stator magnetic circuit is easy to saturate, reduces the weight of the motor, greatly improves the flux density amplitude of an air gap, and greatly improves the torque density of the motor. The motor comprises a stator assembly (1), a magnetic conductance modulation unit (2) and a rotor assembly (3) which are arranged from outside to inside. The stator assembly comprises a stator iron core (4) and a stator winding (5), the stator iron core is in a circular ring shape and extends towards the circle center to form a plurality of thin teeth (41), an open groove (42) is formed between every two adjacent thin teeth, and the stator winding is wound around the thin teeth in the open grooves; the magnetic conductance modulation unit comprises a magnetic conductance modulation module (6) and a fixing piece (7), the magnetic conductance modulation module is placed in an air gap between the stator assembly and the rotor assembly, the magnetic conductance modulation module is connected with the stator iron core through the fixing piece, and the rotor assembly is arranged on the innermost circumference.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet torque motors, and in particular to an integrated permeability modulation type high torque density permanent magnet torque motor. Background Art

[0002] The joint torque motors for humanoid robots require low weight, low inertia, and high torque. However, conventional structure torque motors are limited by the development speed of basic materials, and the torque density has reached saturation. Therefore, it is imperative to reasonably innovate the motor electromagnetics and structure.

[0003] Based on the magnetic field modulation effect, the permanent magnet vernier motor has the advantages of relatively simple mechanical structure, high torque density, and low-speed direct drive, and has received more and more attention in recent years. This type of motor is similar to the ordinary permanent magnet synchronous motor in structure, both of which have a stator core, a rotor core, permanent magnets, and an armature winding. However, the stator of the permanent magnet vernier motor is a split-tooth structure, and the number of stator and rotor pole pairs is not equal. The number of stator pole pairs Ps, the number of rotor pole pairs Pr, and the number of stator teeth Z must satisfy Pr = Z ± Ps. Due to the modulation effect of the stator teeth on the rotor magnetic field, the effective working magnetic flux density of the air gap is greatly improved compared with the permanent magnet synchronous motor, which makes the permanent magnet vernier motor have a higher torque density.

[0004] At present, there are few engineering applications of permanent magnet vernier motors, and most of them are academic research. The existing technology of permanent magnet vernier motors generally adopts a split tooth structure (such as Figure 5 As shown in the figure, the magnetic circuit of this stator structure is very easy to saturate, so the stator yoke and the teeth are designed to be very thick, so most of them adopt an outer rotor structure, which is generally heavy. These factors limit the improvement of the motor torque density.

[0005] Patent application CN201610266925.X of Jiangsu University proposes a five-phase fault-tolerant permanent magnet vernier motor with a stator split-tooth outer rotor structure with a magnetic concentration effect. It adopts an outer rotor spoke structure to increase the magnetic density, but the stator still adopts a split-tooth structure. This structure is redundant and bulky, and the stator magnetic circuit is extremely easy to saturate. It will take up a large volume and weight, limiting the improvement of the motor torque density. Summary of the invention

[0006] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide an integrated magnetic permeability modulation type high torque density permanent magnet torque motor, which solves the problem of easy saturation of the stator magnetic circuit, reduces the weight of the motor, and at the same time greatly improves the magnetic density amplitude of the air gap, thereby greatly improving the torque density of the motor.

[0007] The technical solution of the present invention is: the integrated magnetic permeability modulation type high torque density permanent magnet torque motor comprises a stator assembly (1), a magnetic permeability modulation unit (2), and a rotor assembly (3) arranged from outside to inside;

[0008] The stator assembly comprises a stator core (4) and a stator winding (5); the stator core is annular and has a plurality of fine teeth (41) extending toward the center of the circle; open slots (42) are formed between adjacent fine teeth; and the stator winding is wound around the fine teeth in the open slots;

[0009] The magnetic permeability modulation unit comprises a magnetic permeability modulation module (6) and a fixing member (7). The magnetic permeability modulation module is placed in the air gap between the stator assembly and the rotor assembly. The magnetic permeability modulation module is connected to the stator core via the fixing member. The rotor assembly is arranged on the innermost circumference.

[0010] An open slot is formed between adjacent fine teeth of the stator of the present invention, which increases the effective area in the slot and facilitates offline operation. It solves the problem of easy saturation of the stator magnetic circuit and also greatly reduces the weight of the iron core. The magnetic permeability modulation module is placed in the air gap between the stator assembly and the rotor assembly. The excitation magnetic field generated by the permanent magnet generates two main working magnetic fields in the air gap through the modulation of the magnetic permeability modulation module. The pole pairs are |Z-Pr| and Pr, respectively. The magnetic field with the pole pair number of Pr is the main magnetic field, while the magnetic field with the pole pair number of |Z-Pr| is the harmonic magnetic field. The working magnetic field of an ordinary permanent magnet motor is the main magnetic field. The working magnetic field of the present invention has one more than that of an ordinary permanent magnet motor. The rotor assembly is arranged on the innermost circumference to produce a magnetic concentration effect, which greatly improves the working magnetic flux amplitude, thereby improving the torque density of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic structural diagram of the integrated permeability modulation high torque density permanent magnet torque motor provided by the present invention.

[0012] Figure 2 This is a schematic diagram of the stator structure of the integrated permeability modulation type high torque density permanent magnet torque motor provided by the present invention.

[0013] Figure 3 A schematic structural diagram of a magnetic permeability modulation unit of an integrated magnetic permeability modulation type high torque density permanent magnet torque motor provided by the present invention.

[0014] Figure 4 A schematic structural diagram of the rotor assembly of the integrated permeability modulation high torque density permanent magnet torque motor provided by the present invention.

[0015] Figure 5 It is a schematic diagram of the split-tooth stator structure in the prior art.

[0016] Figure 6 This is a comparison diagram of the stator tooth magnetic flux of the example motor of the present invention and the split-tooth motor.

[0017] Figure 7 This is a comparison diagram of the stator yoke magnetic flux of the example motor of the present invention and the split-tooth motor.

[0018] Figure 8 This is a comparison diagram of the air gap harmonic flux density amplitudes of the example motor of the present invention and the split-tooth motor. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] In order to make the description of the present disclosure more detailed and complete, the following provides an illustrative description of the implementation and specific embodiments of the present invention; however, this is not the only form of implementing or using the specific embodiments of the present invention. The implementation covers the features of multiple specific embodiments and the method steps and sequences used to construct and operate these specific embodiments. However, other specific embodiments can also be used to achieve the same or equivalent functions and step sequences.

[0021] like Figure 1-Figure 4 As shown, this integrated permeability modulation type high torque density permanent magnet torque motor includes a stator assembly 1, a permeability modulation unit 2, and a rotor assembly 3 arranged from outside to inside;

[0022] The stator assembly includes a stator core 4 and a stator winding 5. The stator core is annular and has a plurality of fine teeth 41 extending toward the center of the circle. Open slots 42 are formed between adjacent fine teeth. The stator winding is wound around the fine teeth in the open slots.

[0023] The magnetic permeability modulation unit includes a magnetic permeability modulation module 6 and a fixing member 7. The magnetic permeability modulation module is placed in the air gap between the stator assembly and the rotor assembly. The rotor assembly is arranged on the innermost circumference.

[0024] The magnetic permeability modulation module is connected to the stator core through a fixing piece.

[0025] An open slot is formed between adjacent fine teeth of the stator of the present invention, which increases the effective area in the slot and facilitates offline operation. It solves the problem of easy saturation of the stator magnetic circuit and also greatly reduces the weight of the iron core. The magnetic permeability modulation module is placed in the air gap between the stator assembly and the rotor assembly. The excitation magnetic field generated by the permanent magnet generates two main working magnetic fields in the air gap through the modulation of the magnetic permeability modulation module. The pole pairs are |Z-Pr| and Pr, respectively. The magnetic field with the pole pair number of Pr is the main magnetic field, while the magnetic field with the pole pair number of |Z-Pr| is the harmonic magnetic field. The working magnetic field of an ordinary permanent magnet motor is the main magnetic field. The working magnetic field of the present invention has one more than that of an ordinary permanent magnet motor. The rotor assembly is arranged on the innermost circumference to produce a magnetic concentration effect, which greatly improves the working magnetic flux amplitude, thereby improving the torque density of the motor.

[0026] Preferably, if Figure 1As shown, the fixing member includes an arc portion 71, a first vertical portion 72, and a second vertical portion 73. The magnetic permeability modulation module is arranged in a space surrounded by the arc portion, the first vertical portion, and the second vertical portion, and the arc portion seals the opening of the open slot. In this way, the magnetic permeability modulation unit can be more firmly connected to the stator core.

[0027] Preferably, if Figure 1 As shown, the end surface of the first vertical portion is partially connected to the arc portion, and the end surface of the second vertical portion is completely connected to the arc portion. The gap between the stator core and the magnetic permeability modulation module is well filled to form an integrated structure, making the structure more solid.

[0028] Preferably, the rotor assembly includes a permanent magnet 8 and a magnetic circuit module 9, wherein multiple permanent magnets are evenly distributed along the circumference, and a magnetic circuit module is placed between two adjacent permanent magnets. The spoke-type rotor assembly including the adjustable magnetic circuit module can concentrate magnetic flux, greatly increase the air gap magnetic flux amplitude, and greatly improve the torque density of the motor.

[0029] Preferably, the number of magnetic circuit modules between two permanent magnets is 1-3. Figure 4 As shown, the number of magnetic circuit modules between the two permanent magnets is 3.

[0030] Preferably, the magnetic circuit module is a soft magnetic material such as steel, iron, or iron-cobalt alloy, or a hard magnetic material such as neodymium iron boron or ferrite.

[0031] The magnetization direction of the permanent magnet 8 is as follows Figure 4 As shown by the arrows, the polarities of the two adjacent permanent magnets are opposite, and the working magnetic flux density of the motor is increased through the magnetic field gathering effect of the adjacent permanent magnets with the same polarity.

[0032] When the magnetic circuit module is made of hard magnetic material, the magnetization direction is the radial direction of the circumference or the direction that forms a certain angle with the tangential direction. This forms a unidirectional magnetic Halbach array magnetic field, which also plays a role in improving the working magnetic flux density of the air gap.

[0033] Preferably, if Figure 1 As shown, the number of stator slots is Q = 18, the number of stator pole pairs is Ps = 3, the number of permeability modulation modules is Z = 36, and the number of rotor pole pairs is Pr = 33. Each parameter satisfies the relationship: Z = 2Q, Pr = Z ± Ps.

[0034] Figure 5This is a schematic diagram of a conventional split-tooth stator structure, which is completely consistent with the external dimensions of the motor stator (including the magnetic permeability modulation module) of the present invention. Comparing these two motors with different structures, under the same electrical load, the output torque density of the motor of the present invention is 1.2 times that of the conventional split-tooth motor. Since the number of stator magnetic field pole pairs is much smaller than that of the rotor magnetic field, when the main magnetic flux lines with low pole pairs pass through the rotor, they will be forced to bypass the reverse magnetic poles and enter the nearby air gap area. This magnetic barrier effect will increase the magnetic resistance of the main magnetic circuit. The presence of the separate magnetic permeability modulation module enhances this magnetic barrier effect, thereby weakening the armature reaction of the motor and reducing the magnetic saturation of the motor. Figures 6 to 8 This is a comparison diagram of the magnetic flux density of two motors with the structure of the present invention and the conventional split-tooth structure under the same electrical load. Figure 6 The peak tooth flux density of the stator of the conventional split-tooth motor is 2.12T, and the peak tooth flux density of the stator of the example motor is 1.74T; Figure 7 The peak yoke magnetic flux density of the stator of the conventional split-tooth motor is 2.37T, and the peak yoke magnetic flux density of the stator of the example motor is 1.98T; Figure 8 The harmonic orders of the effective working magnetic flux of the medium motor are 1 and 11. The fundamental magnetic flux of the air gap of the conventional split-tooth motor is 0.21T, and the 11th magnetic flux is 1.38T; the fundamental magnetic flux of the air gap of the example motor is 0.31T, and the 11th magnetic flux is 1.58T.

[0035] It can be seen that the stator adopts an open slot plus an integrated magnetic permeability modulation structure to effectively reduce the stator magnetic saturation, while increasing the amplitude of the effective working magnetic flux density, thereby improving the overload capacity and torque density of the motor compared to the conventional split tooth structure.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. Integrated permeability modulation type high torque density permanent magnet torque motor, characterized by: It comprises a stator assembly (1), a magnetic permeability modulation unit (2), and a rotor assembly (3) arranged from outside to inside; the stator assembly comprises a stator core (4) and a stator winding (5); the stator core is annular and has a plurality of fine teeth (41) extending toward the center of the circle; open slots (42) are formed between adjacent fine teeth; and the stator winding is wound around the fine teeth in the open slots; The magnetic permeability modulation unit comprises a magnetic permeability modulation module (6) and a fixing member (7). The magnetic permeability modulation module is placed in the air gap between the stator assembly and the rotor assembly. The magnetic permeability modulation module is connected to the stator core via the fixing member. The rotor assembly is arranged on the innermost circumference.

2. The integrated permeability modulation type high torque density permanent magnet torque motor according to claim 1, characterized in that: The fixing member comprises an arc portion (71), a first vertical portion (72), and a second vertical portion (73); the magnetic permeability modulation module is arranged in a space surrounded by the arc portion, the first vertical portion, and the second vertical portion; and the arc portion seals the opening of the open slot.

3. The integrated permeability modulation type high torque density permanent magnet torque motor according to claim 2, characterized in that: An end surface portion of the first vertical portion is connected to the arc portion, and an end surface of the second vertical portion is entirely connected to the arc portion.

4. The integrated permeability modulation type high torque density permanent magnet torque motor according to claim 1, characterized in that: The rotor assembly comprises permanent magnets (8) and a magnetic circuit module (9). A plurality of permanent magnets are evenly distributed along the circumference, and the magnetic circuit module is placed between two adjacent permanent magnets.

5. The integrated permeability modulation type high torque density permanent magnet torque motor according to claim 4, characterized in that: The number of magnetic circuit modules between two permanent magnets is 1-3.

6. The integrated permeability modulation type high torque density permanent magnet torque motor according to claim 4, characterized in that: The magnetic circuit module is a soft magnetic material such as steel, iron, or iron-cobalt alloy, or a hard magnetic material such as neodymium iron boron or ferrite.

7. The integrated permeability modulation type high torque density permanent magnet torque motor according to claim 6, characterized in that: When the magnetic circuit module is made of hard magnetic material, the magnetization direction is the radial direction of the circumference or a direction forming a certain angle with the tangential direction.

8. The integrated permeability modulation type high torque density permanent magnet torque motor according to claim 1, characterized in that: The number of stator slots is Q=18, the number of stator pole pairs is Ps=3, the number of magnetic permeability modulation modules is Z=36, and the number of rotor pole pairs is Pr=33.

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