A multi-tooth structure magnetic concentrating stator double-partition motor

Abstract

The present invention relates to the technical field of motors, and discloses a multi-tooth structure magnetic-concentrating stator double-zone motor, comprising an inner zone stator, an intermediate rotor and an outer zone stator arranged concentrically; an outer air gap is arranged between the outer zone stator and the intermediate rotor, and an inner air gap is arranged between the inner zone stator and the intermediate rotor; the inner zone stator comprises an inner zone stator core and a permanent magnet arranged on the inner zone stator core, the intermediate rotor comprises a magnetic conductive block and an insulating block arranged staggered along the circumferential direction, and the outer zone stator comprises an outer zone stator core and an armature winding arranged on the outer zone stator core. Compared with the prior art, the outer zone stator magnetic pole of the present invention adopts a multi-tooth structure of "end teeth-rectangular slots-intermediate teeth-rectangular slots-end teeth", the inner zone stator magnetic pole adopts a magnetic-concentrating structure of "stator teeth-permanent magnets-magnetic-concentrating teeth-permanent magnets-stator teeth", the corresponding components on the inner and outer zone stator magnetic poles are aligned, the air gap magnetic density of the stator zone motor is improved, and the motor efficiency is improved while the motor torque density is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a multi-tooth structure magnetic concentrating stator double-partition motor for electric vehicles. 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.

[0004] Therefore, Professor ZQ Zhu and others proposed a stator permanent magnet motor structure with stator partitioning in the paper "Novel electrical machines having separate PM excitation stator" 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 in 2015. The armature winding is located on the outer stator and the permanent magnet is located on the inner stator, which 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, since there are two air gaps between the two-partition stator and rotor in the stator partitioned permanent magnet motor, its no-load air gap flux density and output torque under equal electrical load are weakened compared with the original single-gap permanent magnet flux switching motor. Although the torque output can be increased by increasing the electrical load in the motor, its efficiency is relatively reduced. Therefore, for the stator partitioned permanent magnet motor, how to improve the permanent magnet air gap flux density, motor torque density and efficiency of the stator partitioned permanent magnet motor is an issue that needs 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 structure, magnetic-concentrating stator, double-partitioned motor structure with high torque density and high efficiency, so as to improve the no-load air gap magnetic flux density of the conventional stator partitioned permanent magnet motor.

[0007] Technical solution: The present invention provides a multi-tooth structure magnetic concentrating stator double-zone motor, comprising a concentrically arranged inner zone stator, an intermediate rotor surrounding the inner zone stator, and an outer zone stator surrounding the intermediate rotor;

[0008] An outer air gap is provided between the outer zone stator and the intermediate rotor, and an inner air gap is provided between the inner zone stator and the intermediate rotor;

[0009] The inner stator comprises an inner stator core and a permanent magnet arranged on the inner stator core, the intermediate rotor comprises magnetic conductive blocks and insulating blocks arranged alternately along the circumferential direction, and the outer stator comprises an outer stator core and an armature winding arranged on the outer stator core;

[0010] The inner partition stator and the outer partition stator are fixedly connected to the motor housing, and the intermediate rotor is fixedly connected to the motor output shaft via a rotor bracket.

[0011] Furthermore, the outer zone stator core includes an outer zone stator yoke and S outer zone stator teeth evenly distributed along the inner circumference of the outer zone stator yoke, each outer zone stator tooth includes a tooth neck and a tooth shoe, an outer zone stator slot is formed between any two adjacent tooth necks, and three magnetic adjustment teeth are convexly provided on each tooth shoe.

[0012] Furthermore, S outer-region stator slots are formed in the outer-region stator core, which are distributed along the circumference at intervals and face the intermediate rotor, and the armature windings are distributed in the S outer-region stator slots and wound on the tooth necks.

[0013] Furthermore, the center line of the middle 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 convex tooth and the end convex teeth on both sides thereof.

[0014] Furthermore, the inner zone stator core includes S "U"-shaped cores and S isosceles trapezoidal magnetic concentrating teeth evenly spaced along the circumference to form a circular ring, the left and right "U"-shaped sides of the "U"-shaped core are marked as stator teeth, the opening of the "U"-shaped core faces the intermediate rotor, and its two side end faces and the waist faces of the magnetic concentrating teeth are all facing the circumferential direction and are not directly connected to form a trapezoidal gap, and the permanent magnets are fixedly embedded in the gap; the long sides of the isosceles trapezoidal magnetic concentrating teeth face the intermediate rotor.

[0015] Furthermore, the "stator tooth-permanent magnet-magnetic tooth-permanent magnet-stator tooth" on the inner zone stator constitutes an inner zone stator pole, and the two permanent magnets of each inner zone stator pole are located on both sides of the isosceles trapezoidal magnetic tooth, and their magnetization directions are all along the circumference pointing to the direction of the middle isosceles trapezoidal magnetic tooth.

[0016] Furthermore, the center line of the magnetic focusing tooth is aligned with the radial center line of the middle convex tooth, the center line of the end face of the permanent magnet close to the middle rotor is aligned with the center line of the rectangular slot, and the center lines of the end face of the two stator teeth on the "U"-shaped iron core close to the middle rotor are respectively aligned with the center lines of the end convex teeth on both sides of the magnetic modulation convex tooth.

[0017] Furthermore, the permanent magnet is made of neodymium iron boron permanent magnet material.

[0018] Beneficial effects:

[0019] 1. Based on the conventional stator partitioned motor structure, the present invention adopts a multi-tooth structure of "end tooth-rectangular slot-middle tooth-rectangular slot-end tooth" in each magnetic pole of the outer stator, and adopts a magnetic field gathering structure of "inner stator tooth-permanent magnet-magnetic field gathering tooth-permanent magnet-inner stator tooth" on the inner stator, as well as an alignment structure of corresponding components on the inner and outer stator poles, which can improve the air gap magnetic density of the stator partitioned motor, thereby improving the motor efficiency while improving the motor torque density.

[0020] 2. The permanent magnets and windings of the present invention 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 and torque density are increased, while the temperature rise of the motor windings and permanent magnets is reduced, thereby improving the working stability of the permanent magnets and the reliability of the motor operation.

[0021] 3. The intermediate rotor used in the motor of the present invention has a simple structure, has neither permanent magnetic material nor windings, and is only composed of alternating magnetic blocks and insulating blocks, and is particularly suitable for high-speed operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the radial cross-section structure of the motor of the present invention;

[0023] Figure 2 It is a radial cross-sectional view of the outer region stator of the present invention;

[0024] Figure 3 is a radial cross-sectional view of the intermediate rotor of the present invention;

[0025] Figure 4 is a radial cross-sectional view of the inner region stator of the present invention;

[0026] Figure 5 (a)- Figure 5(d) is the flux path of the coil X turns when the rotor is in different positions of the present invention;

[0027] Figure 6 Schematic diagram of the permanent magnetic flux linkage and induced back electromotive force of the coil X turn chain when the rotor of the present invention is at four typical positions;

[0028] Figure 7 (a)- Figure 7 (c) is a simulation waveform diagram of the permanent magnet flux linkage, no-load back electromotive force and internal and external air gap magnetic flux density of the present invention.

[0029] In the figure: 1, outer zone stator, 1-1, outer zone stator yoke, 1-2, tooth neck, 1-3, tooth shoe, 1-4, middle convex tooth, 1-5, end convex tooth, 1-6, outer zone stator slot, 1-7, rectangular slot, 2, intermediate rotor, 2-1, insulating block, 2-2, magnetic conductive block, 3, inner zone stator, 3-1, "U" shaped core, 3-2, magnetic concentrating tooth, 3-3, permanent magnet, 3-4, stator tooth, 4, armature winding. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings.

[0031] by Figure 1 Taking the three-phase outer zone stator 6 slots / intermediate rotor 10 poles / inner zone stator 6 poles stator partition motor as an example, the technical solution of the present invention is specifically described.

[0032] The motor structure of the present invention is as follows Figure 1 As shown, it includes a concentrically arranged inner zone stator 3, an intermediate rotor 2 surrounding the inner zone stator 3, and an outer zone stator 1 surrounding the intermediate rotor 2. An outer air gap is provided between the outer zone stator 1 and the intermediate rotor 2, and an inner air gap is provided between the inner zone stator 3 and the intermediate rotor 2. The inner zone stator 3 includes an inner zone stator core and a permanent magnet 3-3 provided on the inner zone stator core, the intermediate rotor 2 includes magnetic conductive blocks 2-2 and insulating blocks 2-1 arranged alternately in the circumferential direction, and the outer zone stator 1 includes an outer zone stator core and an armature winding 4 provided on the outer zone stator core. The inner zone stator 3 and the outer zone stator 1 are fixedly connected to the housing, and the intermediate rotor 2 is fixedly connected to the output shaft through a rotor bracket.

[0033] In the present embodiment, the armature winding 4 is a three-phase concentrated armature winding.

[0034] In this embodiment, the structure of the intermediate rotor 2 is as follows: Figure 3 As shown, 10 insulating blocks 2-1 and 10 magnetic conductive blocks 2-2 are arranged alternately along the circumferential direction.

[0035] The structure of the outer stator 1 is as follows Figure 2As shown, the outer stator core includes an outer stator yoke 1-1 and S outer stator teeth evenly distributed along the inner circumference of the outer stator yoke 1-1. In this embodiment, S is 6.

[0036] Each outer stator tooth includes a tooth neck 1-2 and a tooth shoe 1-3. An outer stator slot 1-6 is formed between any two adjacent tooth necks 1-2. Three rectangular magnetic adjustment convex teeth are protruded on each tooth shoe 1-3. The radial center line of the middle convex tooth 1-4 among the three magnetic adjustment convex teeth is aligned with the center line of the tooth neck 1-2 on the same outer stator tooth. Two rectangular slots 1-7 are formed between the middle convex tooth 1-4 and the end convex teeth 1-5 on both sides thereof. Therefore, the outer stator core has 6 outer stator slots 1-6 distributed along the circumference and facing the intermediate rotor 2. The 3-phase concentrated armature winding 4 is distributed in the 6 outer stator slots 1-6 and wound on the corresponding tooth necks 1-2.

[0037] The structure of the inner stator 3 is as follows Figure 4 As shown, because S is 6, the inner zone stator core includes 6 "U" shaped cores 3-1 and 6 isosceles trapezoidal magnetic teeth 3-2. The 6 "U" shaped cores 3-1 and 6 isosceles trapezoidal magnetic teeth 3-2 are evenly spaced and arranged in a circular ring along the circumference. The opening of the "U" shaped core 3-1 faces the intermediate rotor 2, and the two side end faces of the "U" shaped core 3-1 and the waist faces of the isosceles trapezoidal magnetic teeth 3-2 are all facing the circumferential direction. The long sides of the isosceles trapezoidal magnetic teeth 3-2 face the intermediate rotor 2, and the short sides are close to the direction of the shaft, so the two sides of the isosceles trapezoidal magnetic teeth 3-2 spread outward. There is a trapezoidal gap with the radial inner side as the top and the outer side as the bottom between the "U"-shaped iron core 3-1 and its adjacent isosceles trapezoidal magnetic tooth 3-2. Trapezoidal permanent magnets 3-3 are fixedly embedded in the trapezoidal gap to form 6 inner-zone stator poles. The two "U"-shaped sides of the "U"-shaped iron core 3-1 are recorded as stator teeth 3-4. Then "stator tooth 3-4-permanent magnet 3-3-magnetic tooth 3-2-permanent magnet 3-3-stator tooth 3-4" on the inner-zone stator 3 constitute an inner-zone stator pole. The two permanent magnets 3-3 of each inner-zone stator pole are located on both sides of the isosceles trapezoidal magnetic tooth 3-2, and their magnetization directions are all along the circumference pointing to the direction of the middle isosceles trapezoidal magnetic tooth 3-2. The permanent magnet 3-3 is made of RuFeB permanent magnet material.

[0038] The center line of the isosceles trapezoidal magnetic teeth 3-2 of the inner zone stator is aligned with the radial center line of the middle convex teeth 1-4 on the outer zone stator teeth, the center line of the end face of the permanent magnet 3-3 on the inner zone stator close to the intermediate rotor 2 is aligned with the center line of the rectangular slot 1-7 on the outer zone stator teeth, and the center line of the end face of the two stator teeth 3-4 of the "U"-shaped iron core 3-1 on the inner zone stator 3 close to the intermediate rotor 2 is respectively aligned with the center lines of the two end convex teeth 1-5 on the outer zone stator teeth.

[0039] Figure 5The operating principle of the motor described in this embodiment is shown. For the sake of simplicity, the generation of permanent magnet flux and no-load back electromotive force is introduced by taking coil X as an example. Figure 5 As shown in (a), when the intermediate rotor 2 is at position A, following the "principle of minimum magnetic resistance", the magnetic lines of force flowing through the coil X flow from the outer stator 1 through the intermediate rotor 2 into the inner stator 3 according to the magnetization direction of the permanent magnet. According to the definition of the positive direction of the finite element magnetic flux, the permanent magnetic flux in the coil X is the maximum value at this time. Figure 5 As shown in (c), when the rotor is at position C, the magnitude of the flux flowing through coil X remains unchanged, but the direction of the magnetic lines of force changes. At this time, the permanent magnetic flux in coil X is the reverse maximum value. When the rotor is at positions B and D, as shown in Figure 5 (b) and Figure 5 As shown in (d), the magnetic resistance of the magnetic circuit flowing through coil X is the largest, so the permanent magnetic flux is 0. When the motor rotor rotates continuously, the direction of the magnetic flux in the coil X is as follows: Figure 6 As shown in the figure, it changes periodically. According to Faraday's law of electromagnetic induction, a counter electromotive force is induced in the coil X. Figure 7 (a) shows the permanent magnet flux and no-load back EMF of the motor when it is running at no-load by finite element simulation, which shows a large no-load back EMF amplitude and good sinusoidality, so vector control can be used. Figure 7 (b) shows the radial air gap flux simulation curve of the inner and outer air gaps when the motor is running at no-load. The inner and outer air gap flux amplitudes reach 2.23T and 1.52T respectively, so a larger torque density and higher efficiency can be achieved.

[0040] The present invention solves the problem of mutual spatial restriction between permanent magnets and armature windings in conventional stator permanent magnet motors by adopting a stator double-partition motor with a multi-tooth magnetic concentration permanent magnet structure, reduces the temperature rise of the permanent magnets and thus improves the stability of the permanent magnet working point, and 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 motor efficiency.

[0041] 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 multi-tooth structure magnetic concentrating stator dual-partition motor, characterized in that: It comprises a concentrically arranged inner stator (3), an intermediate rotor (2) surrounding the inner stator (3), and an outer stator (1) surrounding the intermediate rotor (2); An outer air gap is provided between the outer zone stator (1) and the intermediate rotor (2), and an inner air gap is provided between the inner zone stator (3) and the intermediate rotor (2); The inner region stator (3) comprises an inner region stator core and a permanent magnet (3-3) arranged on the inner region stator core, the intermediate rotor (2) comprises magnetic conductive blocks (2-2) and insulating blocks (2-1) arranged alternately in a circumferential direction, and the outer region stator (1) comprises an outer region stator core and an armature winding (4) arranged on the outer region stator core; The inner zone stator (3) and the outer zone stator (1) are fixedly connected to the motor housing, and the intermediate rotor (2) is fixedly connected to the motor output shaft via a rotor bracket; The outer region stator core comprises an outer region stator yoke (1-1) and S outer region stator teeth uniformly distributed along the inner circumference of the outer region stator yoke (1-1), each outer region stator tooth comprises a tooth neck (1-2) and a tooth shoe (1-3), an outer region stator slot (1-6) is formed between any two adjacent tooth necks (1-2), and three magnetic modulation convex teeth are convexly provided on each tooth shoe (1-3); the center line of the middle convex tooth (1-4) among the three magnetic modulation convex teeth is aligned with the center line of the tooth neck (1-2) on the same outer region stator tooth, and two rectangular slots (1-7) are formed between the middle convex tooth (1-4) and the end convex teeth (1-5) on both sides thereof; The outer region stator core is formed with S outer region stator slots (1-6) which are distributed at intervals along the circumference and face the intermediate rotor (2); the armature winding (4) is distributed in the S outer region stator slots (1-6) and is wound on the tooth neck (1-2); The inner zone stator core comprises S "U"-shaped cores (3-1) and S isosceles trapezoidal magnetic concentrating teeth (3-2) which are evenly spaced and arranged in a circular ring along the circumference; the "U"-shaped sides on the left and right sides of the "U"-shaped core (3-1) are marked as stator teeth (3-4); the opening of the "U"-shaped core (3-1) faces the intermediate rotor (2); the end faces on both sides thereof and the waist faces of the magnetic concentrating teeth (3-2) face the circumferential direction and are not directly connected to form a trapezoidal gap, in which the permanent magnets (3-3) are fixedly embedded; the long sides of the magnetic concentrating teeth (3-2) face the intermediate rotor (2); The "stator tooth (3-4)-permanent magnet (3-3)-magnetic focusing tooth (3-2)-permanent magnet (3-3)-stator tooth (3-4)" on the inner region stator (3) constitutes an inner region stator magnetic pole, and the two permanent magnets (3-3) of each inner region stator magnetic pole are both located on both sides of the isosceles trapezoidal magnetic focusing tooth (3-2), and their magnetization directions are all along the circumference pointing to the direction of the middle isosceles trapezoidal magnetic focusing tooth (3-2).

2. The multi-tooth structure magnetic concentrating stator dual-partition motor according to claim 1 is characterized in that: The center line of the magnetic focusing tooth (3-2) is aligned with the radial center line of the middle convex tooth (1-4), the center line of the end face of the permanent magnet (3-3) close to the middle rotor (2) is aligned with the center line of the rectangular slot (1-7), and the center lines of the end faces of the two stator teeth (3-4) on the "U"-shaped iron core (3-1) close to the middle rotor (2) are respectively aligned with the center lines of the end convex teeth (1-5) on both sides of the magnetic modulation convex tooth.

3. The multi-tooth structure magnetic concentrating stator dual-partition motor according to claim 1 or 2, characterized in that: The permanent magnet (3-3) is made of neodymium iron boron permanent magnet material.

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