A stator short-distance separation type motor structure

Abstract

The present invention relates to the field of motor technology, and discloses a stator short-distance separation type motor structure, comprising a concentrically arranged rotor, an inner zone stator surrounding the rotor, and an outer zone stator surrounding the inner zone stator; an outer air gap is arranged between the outer zone stator and the inner zone stator, and an inner air gap is arranged between the inner zone stator and the rotor; the outer zone stator comprises an outer zone stator core and a concentrated armature winding arranged on the outer zone stator core, the inner zone stator is composed of radially alternately magnetized permanent magnets, and the rotor is composed of a rotor yoke and rotor teeth protruding from the rotor yoke; the inner zone stator and the outer zone stator are fixedly connected to the motor housing, and the rotor is fixedly connected to the rotating shaft of the motor. Compared with the prior art, the present invention adopts a stator short-distance separation type structure on the basis of a conventional stator double zone motor structure, adopts a multi-tooth structure in each magnetic pole of the outer zone stator, and adopts a radially alternately magnetized permanent magnet structure on the inner zone stator, so as to improve the air gap magnetic density and torque density of the stator zone motor.

Description

Technical Field

[0001] The invention relates to the technical field of motor body design, and in particular to a stator short-distance separation type motor structure for an electric vehicle. Background Art

[0002] As a key component of electric vehicles, the performance of the motor has a significant impact on the entire drive system. In view of the application characteristics of electric vehicles, the problems that need to be solved in the existing technology are: 1. The motor has a large torque output capacity; 2. The motor has high reliability.

[0003] At present, permanent magnet flux switching motors have attracted attention due to their high torque density, high efficiency, and highly robust rotor structure. This structure is essentially a type of stator permanent magnet motor. There are no windings or permanent magnets on the rotor. The windings and permanent magnets are both located on the stator. Due to the magnetic field concentration effect of the permanent magnets on the stator, the motor has a high air gap magnetic density, which can achieve a large torque output capacity and has good application prospects. At the same time, because the permanent magnets and windings are placed on the same part of the motor, namely the stator, the following: 1. The space for placing the windings is reduced, which limits the further improvement of the motor's torque output capacity; 2. The stator magnetic field is saturated to a large extent, which reduces the motor's overload capacity; 3. The risk of permanent magnet temperature rise and irreversible demagnetization is increased. If the permanent magnet is placed on the rotor, such as a surface-mounted permanent magnet synchronous motor, the permanent magnet is placed on the outer surface of the inner rotor and rotates with the rotor, so the installation and fixation of the permanent magnet is difficult, and it is not suitable for high-speed operation of the motor. If the permanent magnet is embedded in the rotor, the complexity of the motor processing increases, and the air gap magnetic flux and torque density of the motor decrease accordingly.

[0004] In 2015, Professor ZQ Zhu and others proposed a stator permanent magnet motor structure with stator partitioning in the paper "Novel electrical machines having separate PM excitationstator" in Volume 51, Issue 4 and the paper "Novel doubly salient permanent magnet machines with partitioned stator and iron pieces rotor" in Volume 51, Issue 5 of IEEE TRANSACTIONS ON MAGNETICS. The armature winding is located on the stator where the armature winding is located, and the permanent magnet is located on the stator where the excitation winding is located. This solves the spatial conflict between the armature winding and the permanent magnet, alleviates the stator temperature rise, and improves the working stability of the permanent magnet.

[0005] However, in conventional stator partitioned permanent magnet motors, the partitioned stators where the permanent magnets and armature windings are located are placed inside and outside the rotor respectively, and the intermediate rotor can only be connected to the shaft through one side of the rotor bracket, which is not conducive to the stable operation of the rotor, especially in high-speed and high-torque operation occasions; and because there are two air gaps between the two partitioned stators and the rotor, compared with the original single air gap permanent magnet flux switching motor, its no-load air gap flux density and output torque under equal electrical load are weakened. Therefore, for stator partitioned motors, how to improve the rotor operation stability and improve the permanent magnet air gap flux density and motor torque density of stator partitioned permanent magnet motors are issues that need attention. Summary of the invention

[0006] Purpose of the invention: In view of the problems existing in the prior art, the present invention provides a multi-tooth stator short-pitch separation motor structure with high torque density, which is suitable for the field of electric vehicle driving and improves the no-load air gap magnetic density of conventional stator partitioned permanent magnet motor.

[0007] Technical solution: The present invention provides a stator short-pitch separation motor structure, comprising a concentrically arranged rotor, an inner zone stator surrounding the rotor and an outer zone stator surrounding the inner zone stator; an outer air gap is arranged between the outer zone stator and the inner zone stator, and an inner air gap is arranged between the inner zone stator and the rotor; the outer zone stator comprises an outer zone stator core and a concentrated armature winding arranged on the outer zone stator core, the inner zone stator is composed of radially alternately magnetized permanent magnets, and the rotor is composed of a rotor yoke and rotor teeth protruding from the rotor yoke; the inner zone stator and the outer zone stator are fixedly connected to the motor housing, and the rotor is fixedly connected to the rotating shaft of the motor.

[0008] Furthermore, the outer stator core includes an outer stator yoke and P s The outer zone stator teeth are evenly distributed along the inner circumference of the outer zone stator yoke, and an outer zone stator slot is formed between any two adjacent outer zone stator teeth. Each outer zone stator tooth includes a tooth neck and a tooth shoe, and each tooth shoe is convexly provided with three rectangular magnetic adjustment convex teeth.

[0009] Furthermore, the outer stator core has P s The outer stator slots are spaced apart and distributed along the inner circumference of the outer stator yoke and face the rotor, m The phase armature windings are distributed in P s The outer stator slots are wound on the outer stator teeth to meet the P s =6 n ,in n Is a positive integer.

[0010] Furthermore, the center line of the middle magnetic modulation convex tooth among the three magnetic modulation convex teeth is aligned with the center line of the tooth neck on the same outer zone stator tooth, and two rectangular grooves are formed between the middle magnetic modulation convex tooth and the end magnetic modulation convex teeth on both sides thereof.

[0011] Furthermore, the inner zone stator is composed of P s The permanent magnets are fixedly connected along the circumferential direction, and the adjacent permanent magnets are magnetized alternately in the radial direction.

[0012] Furthermore, the permanent magnet is made of neodymium iron boron permanent magnet material.

[0013] Furthermore, the radial centerline of each permanent magnet on the inner stator is aligned with the radial centerline of the outer stator slot, and the connecting surface between adjacent permanent magnets on the inner stator 2 is aligned with the radial centerline of the outer stator tooth neck.

[0014] Furthermore, the rotor teeth on the rotor are evenly distributed on the rotor yoke along the outer circumferential direction of the rotor yoke.

[0015] Beneficial effects:

[0016] 1. Based on the conventional stator double-zone motor structure, the present invention adopts a stator short-distance separation structure of "outer zone stator-inner zone stator-rotor", adopts a multi-tooth structure in each magnetic pole of the outer zone stator, and adopts a radial alternating magnetization permanent magnet structure on the inner zone stator, which can improve the air gap magnetic flux density and torque density of the stator zone motor.

[0017] 2. Due to the adoption of the stator short-distance separation structure of "outer stator-inner stator-rotor", compared with the stator double-partition motor structure of "outer stator-rotor-inner stator", the inner diameter of the rotor can be fixedly connected with the outer diameter of the shaft, which has better operating stability.

[0018] 3. In the present invention, since the permanent magnets and windings are placed in different parts of the motor respectively, the inner partition stator has permanent magnets but no windings, and the outer partition stator has only armature windings but no permanent magnets. Compared with the conventional stator permanent magnet motor, the winding placement space is increased, the motor output torque can be increased, and since the temperature rise of the motor windings and permanent magnets is reduced, the working stability of the permanent magnets and the reliability of the motor operation are improved.

[0019] 4. The rotor adopted in the present invention has a simple structure, has neither permanent magnetic material nor winding, has high robustness, and is particularly suitable for high-speed operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the radial cross-section structure of a motor according to an embodiment of the present invention;

[0021] Figure 2 This is a radial cross-sectional view of the stator in the outer region of the motor according to an embodiment of the present invention;

[0022] Figure 3 This is a radial cross-sectional view of the stator in the inner area of ​​the motor according to an embodiment of the present invention;

[0023] Figure 4 This is a radial cross-sectional view of a motor rotor according to an embodiment of the present invention;

[0024] Figure 5 It is the simulation waveform diagram of no-load back electromotive force and internal and external air gap magnetic flux density of the present invention, wherein, Figure 5 (a) is the no-load back electromotive force of the motor when it is running at no-load by finite element simulation; Figure 5 (b) is the radial air gap flux density simulation curve of the inner air gap when the motor is running at no load; Figure 5 (c) is the radial air gap flux simulation curve of the outer air gap when the motor is running at no-load.

[0025] In the figure: 1, outer zone stator, 1-1, armature winding, 1-2, outer zone stator yoke, 1-3, tooth neck, 1-4, tooth shoe, 1-5, magnetic adjustment cam, 1-6, outer zone stator slot, 2, inner zone stator, 2-1, permanent magnet, 3, rotor, 3-1, rotor yoke, 3-2, rotor teeth. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with the accompanying drawings.

[0027] by Figure 1-Figure 4 Taking the three-phase outer zone stator 12 slots / inner zone stator 12 poles / rotor 10 poles stator short-pitch separation type motor as an example, the technical solution of the present invention is specifically described.

[0028] The motor of the present invention is Figure 1 As shown, it includes a concentrically arranged rotor 3 , an inner region stator 2 surrounding the rotor 3 , and an outer region stator 1 surrounding the inner region stator 2 .

[0029] An outer air gap is provided between the outer zone stator 1 and the inner zone stator 2, and an inner air gap is provided between the inner zone stator 2 and the rotor 3. The outer zone stator 1 includes an outer zone stator core and a concentrated armature winding 1-1 provided on the outer zone stator core, the inner zone stator 2 is annular and consists of radially alternately magnetized permanent magnets 2-1, and the rotor 3 consists of a rotor yoke 3-1 and rotor teeth 3-2 protruding from the rotor yoke 3-1. The inner zone stator 2 and the outer zone stator 1 are fixedly connected to the motor housing, and the rotor 3 is fixedly connected to the motor shaft.

[0030] like Figure 2 As shown, the outer stator core includes an outer stator yoke 1-2 and P sThe outer zone stator teeth are evenly distributed along the inner circumference of the outer zone stator yoke 1-2, and an outer zone stator slot 1-6 is formed between any two adjacent outer zone stator teeth. Each outer zone stator tooth includes a tooth neck 1-3 and a tooth shoe 1-4, and three rectangular magnetic adjustment convex teeth 1-5 are convexly arranged on each tooth shoe 1-4. The center line of the middle convex tooth among the three magnetic adjustment convex teeth 1-5 is aligned with the center line of the tooth neck 1-3 on the same outer zone stator tooth, and two rectangular slots are formed between the middle convex tooth and the end convex teeth on both sides thereof.

[0031] like Figure 2 As shown, the outer stator slots 1-6 have P s , located in the outer stator core, spaced along the inner circumference of the outer stator yoke 1-2 and facing the rotor 3, m Phase armature winding 1-1 is distributed in P s slots 1-6 and wound on the outer stator teeth to meet P s =6 n ,in n Is a positive integer.

[0032] like Figure 3 As shown, the inner stator 2 is composed of P s The sector annular permanent magnets 2-1 are fixedly connected along the circumferential direction, the inner stator 2 is in annular shape as a whole, adjacent permanent magnets 2-1 are magnetized radially alternately, and the permanent magnets 2-1 are made of neodymium iron boron permanent magnet material. The radial center line of each permanent magnet 2-1 on the inner stator 2 is aligned with the radial center line of the outer stator slot 1-6, and the connection surface between adjacent permanent magnets on the inner stator 2 is aligned with the radial center line of the outer stator tooth neck 1-3.

[0033] like Figure 4 As shown, the rotor teeth 3 - 2 on the rotor 3 are evenly distributed on the rotor yoke 3 - 1 along the outer circumferential direction of the rotor yoke 3 - 1 .

[0034] like Figure 5 (a) shows the no-load back EMF of the motor when it is running at no-load, which is simulated by finite element method. It shows a large no-load back EMF amplitude and good sinusoidality, so vector control can be used. Figure 5 (b) and Figure 5 (c) shows the radial air gap flux simulation curve of the inner and outer air gaps when the motor is running at no-load. The amplitudes of the inner and outer air gap flux densities reach 1.51T respectively, so a larger torque density can be achieved.

[0035] The present invention adopts a stator double-partition motor with a multi-tooth stator and short-distance separation, which not only solves the problem of mutual spatial restriction between the permanent magnet and the armature winding in the conventional stator permanent magnet motor, but also reduces the temperature rise of the permanent magnet and thus improves the stability of the permanent magnet working point, and also reduces the influence of the double air gap on the air gap magnetic flux density, motor torque density and motor efficiency, thereby achieving the purpose of improving the torque density while improving the rotor operation stability.

[0036] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A stator short-distance separation type motor structure, characterized in that: The invention comprises a concentrically arranged rotor (3), an inner region stator (2) surrounding the rotor (3), and an outer region stator (1) surrounding the inner region stator (2); an outer air gap is provided between the outer region stator (1) and the inner region stator (2), and an inner air gap is provided between the inner region stator (2) and the rotor (3); the outer region stator (1) comprises an outer region stator core and a concentrated armature winding (1-1) provided on the outer region stator core; the inner region stator (2) comprises radially alternately magnetized permanent magnets (2-1); the rotor (3) comprises a rotor yoke (3-1) and rotor teeth (3-2) protruding from the rotor yoke (3-1); the inner region stator (2) and the outer region stator (1) are fixedly connected to a motor housing, and the rotor (3) is fixedly connected to a rotating shaft of the motor; The outer stator core comprises an outer stator yoke (1-2) and P s outer region stator teeth evenly distributed along the inner circumference of the outer region stator yoke (1-2), an outer region stator slot (1-6) being formed between any two adjacent outer region stator teeth, each outer region stator tooth comprising a tooth neck (1-3) and a tooth shoe (1-4), and each tooth shoe (1-4) being convexly provided with three rectangular magnetic modulation convex teeth (1-5); The outer zone is formed in the stator core P s The outer region stator slots (1-6) are spaced apart and distributed along the inner circumference of the outer region stator yoke (1-2) and face the rotor (3), and the concentrated armature windings (1-1) are respectively distributed at P s The outer stator slots (1-6) are wound on the outer stator teeth to meet the requirements. P s =6 n ,in n is a positive integer; The inner zone stator (2) is fixedly connected along the circumferential direction by Ps block permanent magnets (2-1), and adjacent permanent magnets (2-1) are magnetized in a radially alternating manner; The radial center line of each permanent magnet (2-1) on the inner zone stator (2) is aligned with the radial center line of the outer zone stator slot (1-6), and the connecting surface between adjacent permanent magnets (2-1) on the inner zone stator (2) is aligned with the radial center line of the outer zone stator tooth neck (1-3).

2. The stator short-pitch separation motor structure according to claim 1 is characterized in that: The center line of the middle magnetic modulation convex tooth among the three magnetic modulation convex teeth (1-5) is aligned with the center line of the tooth neck (1-3) on the same outer zone stator tooth, and two rectangular grooves are formed between the middle magnetic modulation convex tooth and the end magnetic modulation convex teeth on both sides thereof.

3. The stator short-pitch separation motor structure according to claim 1, characterized in that: The permanent magnet (2-1) is made of neodymium iron boron permanent magnet material.

4. The stator short-pitch separation motor structure according to any one of claims 1 to 3, characterized in that: The rotor teeth (3-2) on the rotor (3) are evenly distributed on the rotor yoke (3-1) along the outer circumferential direction of the rotor yoke (3-1).

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