A low mutual inductance motor

Abstract

The application relates to a low mutual inductance motor, which comprises a stator core, a rotating shaft, magnetic steel and winding, the magnetic steel is assembled on the rotating shaft, the stator core is provided with a stator main pole, the winding is wound on the stator main pole, and the stator pole shoe on the stator main pole adopts an asymmetric structure. Compared with the prior art, the application has the advantages of reducing the mutual inductance of the motor and the like.

Description

Technical Field

[0001] This invention relates to an electric motor, and more particularly to a low mutual inductance electric motor. Background Technology

[0002] Permanent magnet synchronous motors use permanent magnets to provide excitation, which simplifies the motor structure, reduces processing and assembly costs, and eliminates the slip rings and brushes that are prone to problems, thus improving the reliability of motor operation. Furthermore, since no excitation current is required, there is no excitation loss, which improves the efficiency and power density of the motor.

[0003] Existing permanent magnet synchronous motor structures such as Figure 1 As shown, its stator poles adopt symmetrical pole shoes, such as Figure 2 As shown, the self-inductance and mutual inductance curves of this ordinary symmetrical pole shoe structure motor are as follows: Figure 3 As shown, the self-inductance and mutual inductance of this motor are generally high, thus it cannot achieve higher speeds and faster current responses. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art and provide a low-inductance motor that reduces the mutual inductance between motor phases.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] According to one aspect of the present invention, a low mutual inductance motor is provided, comprising a stator core, a rotating shaft, magnets, and windings, wherein the magnets are mounted on the rotating shaft, the stator core is provided with stator main poles, the windings are wound on the stator main poles, and the stator pole shoes on the stator main poles adopt an asymmetrical structure.

[0007] As a preferred technical solution, the width bs0 of the slot between adjacent stator main poles of different phases is increased, thereby making the stator pole shoe on the stator main pole an asymmetric structure.

[0008] As a preferred technical solution, the width bs0 of the groove ranges from 0.4 to 1.4 mm.

[0009] As a preferred technical solution, the width bs0 of the groove is preferably 0.9 mm.

[0010] As a preferred technical solution, the thickness hs of the stator pole shoes of adjacent different phases becomes thinner.

[0011] As a preferred technical solution, the thickness hs of the stator pole shoe ranges from 0.4 to 1.4 mm.

[0012] As a preferred technical solution, the thickness hs of the stator pole shoe is preferably 0.9 mm.

[0013] As a preferred technical solution, the motor is a 10-pole, 12-slot motor.

[0014] As a preferred technical solution, the motor is an 8-pole, 9-slot motor.

[0015] As a preferred technical solution, the motor is a 14-pole, 12-slot motor.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1) The present invention uses an asymmetric pole shoe to effectively reduce phase-to-phase mutual inductance, which is applicable to some special control requirements.

[0018] 2) The asymmetrical pole shoe method of this invention can reduce the motor line inductance and the motor's own inductive reactance, thereby increasing the range of high-speed operation of the motor.

[0019] 3) The asymmetrical pole shoe method used in this invention can reduce the motor inductance, reduce the current response time, and enable the motor to achieve higher acceleration and deceleration.

[0020] 4) The present invention adopts an asymmetrical pole shoe method, which can improve the saliency ratio of the surface-mounted permanent magnet synchronous motor and improve the control operating range of this type of motor. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an existing permanent magnet synchronous motor;

[0022] Figure 2 This is a schematic diagram of the symmetrical pole shoe structure of an existing motor;

[0023] Figure 3 The diagram shows the self-inductance and mutual inductance curves of an existing motor.

[0024] Figure 4 This is a schematic diagram of the structure of the motor of the present invention;

[0025] Figure 5 This is a schematic diagram of the asymmetric pole shoe structure of the motor of the present invention;

[0026] Figure 6 The diagram shows the self-inductance and mutual inductance curves of the motor of the present invention.

[0027] Figure 7 This is a schematic diagram of the thinning of the pole shoes in the motor of the present invention;

[0028] Figure 8 This is a graph showing the mutual inductance of the motor in this invention with respect to the pole shoe thickness hs and the slot width bs0.

[0029] 10 is the stator core, 20 is the shaft, 30 is the magnet, 40 is the winding, 101 is the stator main pole, 1011 is the stator pole shoe, and 11 is the slot. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0031] In permanent magnet synchronous motors, lower inductance often translates to higher speeds and faster current response. Furthermore, in multi-phase motor faults, low inter-phase mutual inductance prevents normal phases from continuing to fail due to short circuits. The technical solution of this invention involves asymmetrically changing the symmetrical pole shoes of the existing stator poles, thereby reducing the core coupling between adjacent non-phase windings and thus lowering self-inductance and mutual inductance.

[0032] like Figure 4 As shown, a low mutual inductance motor includes a stator core 10, a rotating shaft 20, a magnet 30, and a winding 40. The magnet 30 is mounted on the rotating shaft 20. The stator core 10 is provided with stator main poles 101. The winding 40 is wound on the stator main poles 101. The stator pole shoes 1011 on the stator main poles 101 adopt an asymmetrical structure.

[0033] The winding is divided into three phases: A, B, and C. Figure 4 Taking a 10-pole, 12-slot motor as an example, in order to generate the maximum electromotive force, the four coils of the same phase are wound on adjacent stator poles, as shown in diagrams A1 and A2. By increasing the width bs0 of the inter-pole slot 11 between stator poles of different phases, the magnetic path coupling between phases can be effectively reduced, thereby effectively reducing the mutual inductance between the windings 40 of each phase, achieving the purpose of this invention.

[0034] The width bs0 of the slot 11 ranges from 0.4 to 1.4 mm. Preferably, the width bs0 of the slot 11 is 0.9 mm.

[0035] like Figure 5 The diagram shows the different magnetic circuits formed after the stator pole shoes are changed from symmetrical pole shoes to asymmetrical pole shoes according to the principle of expanding the slots between different adjacent phases. Figure 5 At the rotor angle position shown, the self-inductance of phase A and the mutual inductance of AB and AC are at their maximum, and the magnetic circuits between different phases become sparse at the enlarged slot opening.

[0036] like Figure 6 The diagram shows the self-inductance and mutual inductance of each phase within the mechanical angle range of 0° to 72° and the electrical angle range of 0° to 360° of the motor rotor rotation, using a 12-slot, 10-pole motor as an example. Figure 2It refers to the self-inductance and mutual inductance of a typical symmetrical pole shoe structure motor. Figure 6 It is an asymmetrical pole shoe motor with reduced self-inductance and mutual inductance, reducing self-inductance by 20% and mutual inductance by 6 times.

[0037] like Figure 7 The diagram illustrates another possible embodiment of a motor with low interphase mutual inductance. Similarly, reducing the thickness hs0 of the pole shoes 1011 between different adjacent phases can also reduce the coupling between different phases and decrease interphase mutual inductance.

[0038] The thickness hs of the stator pole piece 1011 ranges from 0.4 to 1.4 mm. Preferably, the thickness hs of the stator pole piece 1011 is 0.9 mm.

[0039] like Figure 6 As shown, the curves of mutual inductance between motor phases are displayed when the slot width bs0 is increased and the thickness of the adjacent phase pole shoe hs is decreased.

[0040] Furthermore, the technical solution of this invention can be used to reduce mutual inductance between different phases in synchronous motors with adjacent in-phase windings. Examples include 9-slot 8-pole and 12-slot 14-pole motors.

[0041] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low mutual inductance motor, comprising a stator core (10), a rotating shaft (20), a magnet (30), and a winding (40), wherein the magnet (30) is mounted on the rotating shaft (20), the stator core (10) is provided with stator main poles (101), and the winding (40) is wound on the stator main poles (101), characterized in that, The stator pole shoe (1011) on the stator main pole (101) adopts an asymmetric structure; The width bs0 of the slot (11) between adjacent stator main poles (101) of different phases is increased, thereby making the stator pole shoe (1011) on the stator main pole (101) an asymmetrical structure; the width bs0 of the slot (11) is 0.9mm; Alternatively, the thickness hs of the stator pole piece (1011) in adjacent different phases may be thinner; the thickness hs of the stator pole piece (1011) is 0.9 mm.

2. The low mutual inductance motor according to claim 1, characterized in that, This motor is a 10-pole, 12-slot motor.

3. A low mutual inductance motor according to claim 1, characterized in that, This motor is an 8-pole, 9-slot motor.

4. A low mutual inductance motor according to claim 1, characterized in that, This motor is a 14-pole, 12-slot motor.

Images