Double-rotor permanent magnet motor with high torque density

Abstract

The invention relates to a high-torque-density double-rotor permanent magnet motor, belongs to the technical field of permanent magnet motors, and solves the technical problems of reasonably and effectively adjusting an air-gap magnetic field and facilitating processing and assembling based on a magnetic field modulation principle, and adopts the technical scheme that the high-torque-density double-rotor permanent magnet motor comprises a stator, an armature winding, a modulation rotor, a permanent magnet rotor and a stator shell, the stator, the modulation rotor and the permanent magnet rotor are coaxially arranged in the stator shell, the modulation rotor is movably sleeved with the stator, the permanent magnet rotor is movably sleeved with the modulation rotor, and gaps are formed among the stator, the modulation rotor and the permanent magnet rotor; the modulation rotor comprises a left modulation end cover, a right modulation end cover and a plurality of magnetic modulation blocks; the permanent magnet rotor comprises a permanent magnet rotor rotating shaft and a boss. The double-rotor permanent magnet motor has the characteristics of high permanent magnet utilization rate, high output torque, low torque pulsation and high power density, and the permanent magnet utilization rate of the motor can be improved and the torque pulsation can be reduced under the condition that the motor is relatively high in torque density and power density.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnet motors, and in particular relates to a dual-rotor permanent magnet motor with high torque density. Background Art

[0002] With the rise of the new energy revolution, electric vehicles, hybrid vehicles, wind power and wave power generation are accelerating their development. In these new energy fields, the drive motor is the core component of energy conversion, and its performance is directly related to the efficiency and reliability of the entire drive system. At the same time, the drive motor in these applications often requires high torque output at a low speed, such as: generators in wind power generation. The magnetic gear composite motor formed by combining magnetic gears and traditional permanent magnet motors has high torque density, high power density and excellent low-speed high-torque characteristics. Therefore, the magnetic gear composite motor shows potential application prospects in the above application fields.

[0003] At present, many topologies of magnetic gear compound motors based on the principle of magnetic field modulation have been proposed and developed to improve the torque density and power density of the motor. The Chinese patent document with application number 201510824775.5 proposes a dual-mechanical-port dual-electric-port permanent magnet motor, which embeds the magnetic field modulation motor and the traditional permanent magnet motor into the same motor, rationally utilizes the internal space of the motor, and improves the torque density and power density of the motor to a certain extent. However, the structure has two rotors and two stators, forming three layers of air gaps in the middle, and the mechanical structure is relatively complex, requiring high processing and manufacturing technology, and the assembly accuracy of the motor is difficult to guarantee; at the same time, the excitation magnetic field generated by the permanent magnet needs to pass through three layers of air gaps, the magnetic circuit is long, the permanent magnetic field is severely weakened, and the utilization rate of the permanent magnet is reduced, which leads to low torque output capacity and power density of the motor. The Chinese patent document with application number 201811363978.9 proposes a permanent magnet array dual-rotor motor with a double-layer air gap, in which an array of permanent magnets is embedded in the stator slots. A Y-type magnetization method is constructed in a layered manner to reasonably guide the magnetic circuit from the modulating rotor to the stator salient pole teeth, making the magnetic circuit of the stator slot more efficient and reasonable, thereby improving the utilization rate of the permanent magnets and the torque density of the motor. However, due to the presence of permanent magnets between the stator slots, the magnetic field energy storage in the air gap changes dramatically, resulting in a large positioning torque in the motor, which in turn causes the motor to have a large torque pulsation.

[0004] In view of the defects of the above-mentioned prior art, how to reasonably and effectively adjust the air gap magnetic field based on the magnetic field modulation principle to achieve high permanent magnet utilization, high output torque, low torque pulsation, high power density and other performances of the dual-rotor permanent magnet motor is an urgent problem to be solved in the current field of magnetic field modulation motor research. At the same time, for the more complex dual-rotor motor structure, how to ensure the assembly accuracy of the motor and the reliable operation of the motor is a difficult problem that needs to be solved in the current motor processing and manufacturing field. Summary of the invention

[0005] The main purpose of the present invention is to overcome the deficiencies in the prior art and to propose a dual-rotor permanent magnet motor with the characteristics of high permanent magnet utilization, high output torque, low torque pulsation and high power density, so as to ensure that the motor has a higher torque density and power density, improve the utilization rate of the permanent magnets of the motor and reduce the torque pulsation, and meet the overall performance requirements of modern electric vehicles, hybrid vehicles, wind power and wave power generation. At the same time, in view of the relatively complex mechanical structure of the dual-rotor motor, an assembly method based on the dual-rotor motor is provided, which solves the problem of the difficulty in the actual processing and assembly of this type of motor.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a high torque density dual-rotor permanent magnet motor, which includes a stator, an armature winding, a modulation rotor, a permanent magnet rotor and a stator housing, wherein: The stator, the modulation rotor and the permanent magnet rotor are coaxially arranged in the stator housing, the modulation rotor is movably mounted in the stator, the permanent magnet rotor is movably mounted in the modulation rotor, and gaps are arranged between the stator, the modulation rotor and the permanent magnet rotor; A left stator end cover and a right stator end cover are respectively arranged at the left and right end surfaces of the stator housing, a first axial hole is arranged at the center of the left stator end cover, and a second axial hole is arranged at the center of the right stator end cover, and the first axial hole and the second axial hole are arranged coaxially; the stator is fixedly mounted on the inner wall of the stator housing, the stator comprises a stator pole shoe, a stator tooth and a stator yoke, a plurality of stator teeth are evenly distributed on the inner circumferential surface of the stator, the roots of adjacent stator teeth are connected by a stator yoke, an armature winding is wound on the stator teeth, a stator pole shoe is arranged at the end of the stator tooth, the outer walls of the plurality of stator yokes are used as the outer side walls of the stator, and the outer surfaces of the plurality of stator pole shoes are used as the inner side walls of the stator; The modulation rotor comprises a left modulation end cover, a right modulation end cover and a plurality of modulation magnetic blocks, the plurality of modulation magnetic blocks are arranged with gaps in the circumferential direction, the lengths of the plurality of modulation magnetic blocks are equal, the head and tail ends of the modulation magnetic blocks are respectively fixedly connected with the corresponding left modulation end cover and right modulation end cover, a third axial hole is arranged at the center of the left modulation end cover, a sleeve is arranged at the position of the third axial hole, the first axial hole, the third axial hole and the sleeve are arranged coaxially, the sleeve is inserted into the first axial hole, and a first bearing is arranged between the sleeve and the first axial hole; the modulation rotor shaft is arranged at the center of the outer end surface of the right modulation end cover, the modulation rotor shaft passes through the second axial hole and extends to the outside of the stator housing, and a fourth bearing is arranged between the modulation rotor shaft and the second axial hole, thus ensuring that the modulation rotor can rotate freely independently of the stator and output torque; the modulation magnetic block comprises a plurality of first modulation units and a plurality of second modulation units, the first modulation unit and the second modulation unit are arranged at intervals in the circumferential direction, and the pole arc of the first modulation unit is β m1 , the pole arc of the second modulation unit is β m2 , the wall thickness of the first modulation unit and the second modulation unit are equal and meet the constraint condition: 7º≤ β m1 ≤12º, 7º≤ β m2 ≤12º, and β m1 ≠ β m2 The two modulation units adopt special unequal arc designs respectively. By reasonably designing the pole arcs in the modulation units, more useful magnetic field harmonic content can be modulated in the air gap of the motor, further increasing the torque output capacity of the motor. At the same time, the rate of change of the magnetic field energy storage in the air gap to the relative position angle of the stator can be changed, which can effectively reduce the positioning torque of the motor and thus reduce the torque pulsation of the motor. The outer walls of the first modulation units and the second modulation units are used as the outer walls of the magnetic adjustment block, and the inner walls of the first modulation units and the second modulation units are used as the inner walls of the magnetic adjustment block. The radius of the outer wall of the modulation rotor is R mo , the radius of the inner wall of the modulation rotor is R mi , 1.10≤ R mo / R mi ≤1.15; The permanent magnet rotor comprises a permanent magnet rotor shaft and a boss, wherein the boss is arranged in the middle of the permanent magnet rotor and close to one side of the right modulation end cover, one end of the permanent magnet rotor shaft passes through the third shaft hole and the first shaft hole in sequence from the inside to the outside and extends to the outside of the stator housing, a second bearing is arranged between the permanent magnet rotor shaft and the third shaft hole, and the other end of the permanent magnet rotor shaft is installed on the inner end face of the right modulation end cover through the third bearing, thus ensuring that the permanent magnet rotor can rotate freely independently of the modulation rotor and output torque; the radius of the inner circle surface of the boss is R pmi , the radius of the outer surface of the boss is R pmo , and satisfy the constraint relationship: 1.25≤ R pmo / R pmi ≤1.4; a plurality of pole-to-pole slots are arranged on the boss along the axis direction of the permanent magnet rotor, and the pole-to-pole slots are evenly arranged along the circumferential direction of the boss. The pole-to-pole slots are arranged in a V-shape, and the opening direction of the pole-to-pole slots is arranged outward. The angle between the through slots on both sides of the pole-to-pole slots meets 30º≤ θ pm ≤60º, and the bottom of the pole slots are not connected, the outer wall of the boss between the pole slot openings is set as the first rotor salient pole tooth, and the pole arc of the first rotor salient pole tooth is θ 1 The outer wall of the boss between adjacent pairs of pole slots is set as the second rotor salient pole tooth, and the pole arc of the second rotor salient pole tooth is θ 2 , and satisfy the constraints: 5º≤ θ 1 ≤7.5º, 5º≤ θ 2 ≤7.º and θ 1 ≠ θ 2 , through reasonable optimization design of permanent magnet rotor salient pole tooth unit, the positioning torque of the motor can be effectively reduced, thereby reducing torque pulsation. The top of the first rotor salient pole tooth is connected to the top of the second rotor salient pole tooth by a reinforcing rib, and the reinforcing rib can ensure the mechanical strength of the permanent magnet rotor. The shape surrounded by the side wall of the top of the first rotor salient pole tooth, the side wall of the top of the second rotor salient pole tooth and the outer wall of the reinforcing rib is defined as the rotor virtual slot. The pole arc of the rotor virtual slot is θ dThe permanent magnets are respectively inserted into the corresponding pole slots, the number of permanent magnets is the same as the number of virtual slots of the rotor, the two permanent magnets inserted in each pole slot form a group of poles, the magnetization direction of the permanent magnets in each group of poles is perpendicular to the long side of the permanent magnet and points to the inside of the pole slot opening, the gap between the top of each permanent magnet and the corresponding reinforcement rib is set as an external magnetic barrier, and the gap between the bottom of each permanent magnet and the bottom of the pole slot is set as an internal magnetic barrier. The external magnetic barrier and the internal magnetic barrier can prevent magnetic leakage at the end of the permanent magnet and improve the utilization rate of the permanent magnet.

[0007] Furthermore, the armature winding adopts a single-layer distributed winding structure, which is more conducive to improving torque than concentrated winding.

[0008] Furthermore, the number of pole pairs of the armature winding is P s , the number of the magnetic tuning blocks is N , the number of pole pairs of the permanent magnet is P p , satisfying the relationship: N = P s + P p .

[0009] Furthermore, the gap between the inner circumference of the stator and the outer circumference of the modulation rotor is 0.5 mm to 1 mm, and the gap between the inner circumference of the modulation rotor and the outer circumference of the permanent magnet rotor is 0.5 mm to 1 mm.

[0010] Furthermore, the radius of the outer side wall of the stator is R so , the radius of the inner wall of the stator is R si , the pole arc of the stator pole shoe is β p , the pole arc at the root of the stator tooth is β s , the pole arc at the end of the stator tooth is β t , the pole arc of the stator yoke is β y In order to ensure the motor stator slot full rate and mechanical strength, the constraint relationship that needs to be satisfied is: 1.1≤ R so / R si ≤1.3; 2.5≤ β y / β s ≤3, 2≤ β p / β t≤2.5.

[0011] Furthermore, there is a clearance fit between the permanent magnet rotor shaft and the first shaft hole and the third shaft hole, and there is a clearance fit between the modulation rotor shaft and the second shaft hole.

[0012] Furthermore, the thickness of the reinforcing rib is 0.6 mm to 1.1 mm.

[0013] Furthermore, the stator, modulation rotor and permanent magnet rotor are stacked with silicon steel sheets of the same thickness, the thickness of the silicon steel sheets is 0.35 mm, and the stacking coefficient is 0.95; the left modulation end cover, right modulation end cover, left stator end cover, right stator end cover, permanent magnet rotor shaft and modulation rotor shaft are all made of non-magnetic materials; the material of each of the permanent magnets is neodymium iron boron magnetic material.

[0014] Furthermore, the inner diameters of the second bearing, the third bearing and the fourth bearing are equal, and the inner diameter of the first bearing is larger than the inner diameters of the second bearing, the third bearing and the fourth bearing, so as to ensure that the sleeve is rotatably connected to the inner ring of the first bearing, thereby ensuring that the modulation rotor as a whole is coaxial with each bearing.

[0015] The beneficial effects of the present invention are: 1. The present invention adopts a V-shaped permanent magnet topology structure in the permanent magnet rotor. This arrangement makes the permanent magnet have a magnetic field concentration effect, improves the permanent magnet utilization rate of the motor, and makes the motor have a larger internal and external air gap magnetic flux density amplitude under the same permanent magnet dosage, thereby improving the torque output capacity and power density of the motor; the rotor structure with a V-shaped permanent magnet topology can effectively avoid external magnetic leakage and reduce internal magnetic leakage, thereby further improving the permanent magnet utilization rate and torque output capacity; 2. The present invention has a rotor virtual slot on the side of the permanent magnet rotor core close to the air gap, and the pole arc coefficient of the rotor virtual slot is adjustable. By adjusting the pole arc coefficient of the rotor virtual slot, the torque and torque pulsation of the motor can be optimized, thereby enhancing the torque output capacity of the motor and reducing the torque pulsation; 3. The present invention has rotor salient pole teeth on the permanent magnet rotor core, and the rotor salient pole teeth act as magnetic adjustment blocks. Based on the magnetic field modulation principle, the effect of magnetic field modulation can be enhanced, and the harmonic content in the air gap magnetic field can be fully utilized, thereby improving the torque capacity of the motor; at the same time, the rotor salient pole teeth adopt an unequal arc design, that is, the pole arc coefficients of the rotor salient pole tooth unit and the rotor salient pole tooth unit are different, and the pole arc coefficients of the two salient pole tooth units are reasonably optimized and designed to ensure that the positioning torque of the motor is effectively reduced under the condition that the torque output capacity remains unchanged, thereby reducing the torque pulsation; 4. Magnetic barriers are provided at both ends of the permanent magnets of the present invention, which cooperate with the virtual slots of the rotor to effectively avoid magnetic leakage at the ends of the permanent magnets, further improving the utilization rate of the permanent magnets; 5. The modulation rotor in the present invention is formed by a plurality of magnetic modulation blocks arranged in a circumferential array, and the magnetic modulation blocks in the modulation rotor are divided into a first modulation unit and a second modulation unit. The two modulation units adopt an unequal arc design, based on the magnetic field modulation principle, so that more useful magnetic field harmonic content is modulated in the motor air gap, further increasing the torque output capacity of the motor; 6. The magnetic adjustment block in the modulation rotor of the present invention adopts an unequal arc design, which changes the rate of change of the magnetic field energy storage in the air gap to the relative position angle of the stator, effectively reduces the positioning torque of the motor, and thus reduces the torque pulsation of the motor; 7. The present invention uses only one set of armature windings, which cleverly avoids the electromagnetic coupling problem caused by the use of two sets of windings in the traditional double-layer air-gap permanent magnet motor. In addition, the armature winding used in the present invention is located on the stator, and the armature winding does not need to rotate, which avoids the problems of reduced motor operating efficiency and reliability caused by the use of carbon brushes and slip rings, as well as the maintenance of components such as slip rings; 8. The motor assembly of the present invention adopts four bearings to ensure that the stator, stator housing, modulation rotor, modulation rotor housing, modulation rotor output shaft, permanent magnet rotor and permanent magnet rotor output shaft are coaxial, which effectively solves the problem of difficulty in processing and assembling the dual-rotor motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the main cross-sectional structure of the present invention; Figure 2 yes Figure 1 Schematic diagram of the structure of the left view of the middle ab section; Figure 3 yes Figure 2 A magnified schematic diagram of the local structure of the middle stator; Figure 4 yes Figure 2 A magnified schematic diagram of the local structure of the permanent magnet rotor; Figure 5 yes Figure 2 Schematic diagram of the medium modulation rotor structure; Figure 6 It is a schematic diagram of the magnetic flux of the motor operation of the present invention; Figure 7 It is the waveform diagram of the output torque of the motor of the present invention.

[0017] In the figure, 1 is the stator, 1.1 is the stator pole shoe, 1.2 is the stator tooth, 1.3 is the stator yoke; 2 is the armature winding; 3 is the modulation rotor, 3.1 is the left modulation end cover, 3.2 is the right modulation end cover; 4 is the magnetic modulation block, 4.1 is the first modulation unit, 4.2 is the second modulation unit; 5 is the permanent magnet rotor; 6 is the permanent magnet; 7 is the rotor virtual slot; 8.1 is the external magnetic barrier, 8.2 is the internal magnetic barrier; 9 is the permanent magnet rotor shaft; 10 is the reinforcing rib; 11.1 is the first rotor salient pole tooth, 11.2 is the second rotor salient pole tooth; 12 is the modulation rotor shaft; 13 is the stator housing, 13.1 is the left stator end cover, 13.2 is the right stator end cover; 14.1 is the first bearing, 14.2 is the second bearing, 14.3 is the third bearing, and 14.4 is the fourth bearing. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0019] like Figures 1 to 5 A high torque density dual-rotor permanent magnet motor is shown, which comprises a stator 1, an armature winding 2, a modulation rotor 3, a permanent magnet rotor 5 and a stator housing 13, wherein: The stator 1, the modulation rotor 3 and the permanent magnet rotor 5 are coaxially arranged in the stator housing 13, the modulation rotor 3 is movably mounted in the stator 1, the permanent magnet rotor 5 is movably mounted in the modulation rotor 3, and gaps are arranged between the stator 1, the modulation rotor 3 and the permanent magnet rotor 5; A left stator end cover 13.1 and a right stator end cover 13.2 are respectively arranged at the left and right end surfaces of the stator housing 13, a first axial hole is arranged at the center of the left stator end cover 13.1, and a second axial hole is arranged at the center of the right stator end cover 13.2, and the first axial hole and the second axial hole are arranged coaxially; the stator 1 is fixedly mounted on the inner wall of the stator housing 13, the stator 1 comprises a stator pole shoe 1.1, a stator tooth 1.2 and a stator yoke 1.3, a plurality of stator teeth 1.2 are evenly distributed on the inner circumferential surface of the stator 1, 24 stator teeth 1.2 are arranged in this embodiment, the roots of adjacent stator teeth 1.2 are connected by the stator yoke 1.3, the armature winding 2 is wound on the stator teeth 1.2, the stator pole shoe 1.1 is arranged at the end of the stator tooth 1.2, the outer walls of the plurality of stator yokes 1.3 are used as the outer walls of the stator 1, and the outer surfaces of the plurality of stator pole shoes 1.1 are used as the inner walls of the stator 1; The modulation rotor 3 comprises a left modulation end cover 3.1, a right modulation end cover 3.2 and a plurality of modulation magnetic blocks 4, the plurality of modulation magnetic blocks 4 are arranged with gaps along the circumferential direction, the lengths of the plurality of modulation magnetic blocks 4 are equal, the head and tail ends of the modulation magnetic blocks 4 are respectively fixedly connected with the corresponding left modulation end cover 3.1 and right modulation end cover 3.2, a third axial hole is arranged at the center of the left modulation end cover 3.1, a sleeve is arranged at the position of the third axial hole, the first axial hole, the third axial hole and the sleeve are coaxially arranged, the sleeve is inserted into the first axial hole, and the sleeve and the first axial hole are connected. A first bearing 14.1 is arranged between the right modulation end cover 3.2; a modulation rotor shaft 12 is arranged at the center of the outer end surface of the right modulation end cover 3.2, the modulation rotor shaft 12 passes through the second shaft hole and extends to the outside of the stator housing 13, and a fourth bearing 14.4 is arranged between the modulation rotor shaft 12 and the second shaft hole; the magnetic modulation block 4 includes a plurality of first modulation units 4.1 and a plurality of second modulation units 4.2, the first modulation units 4.1 and the second modulation units 4.2 are arranged at intervals along the circumferential direction, and the pole arc of the first modulation unit 4.1 is β m1 , the pole arc of the second modulation unit 4.2 is β m2 , the wall thickness of the first modulation unit 4.1 and the second modulation unit 4.2 are equal and satisfy the constraint condition: 7º≤ β m1 ≤12º, 7º≤ β m2 ≤12º, and β m1 ≠ β m2 The outer walls of the first modulation units 4.1 and the second modulation units 4.2 are used as the outer walls of the magnetic adjustment block 4, and the inner walls of the first modulation units 4.1 and the second modulation units 4.2 are used as the inner walls of the magnetic adjustment block 4. The radius of the outer wall of the modulation rotor 3 is R mo , the radius of the inner wall of the modulation rotor is R mi , 1.10≤ R mo / R mi ≤1.15; The permanent magnet rotor 5 comprises a permanent magnet rotor shaft 9 and a boss, the boss is arranged in the middle of the permanent magnet rotor 5 and close to one side of the right modulation end cover 3.2, one end of the permanent magnet rotor shaft 9 passes through the third shaft hole and the first shaft hole from the inside to the outside in sequence and extends to the outside of the stator housing 13, a second bearing 14.2 is arranged between the permanent magnet rotor shaft 9 and the third shaft hole, and the other end of the permanent magnet rotor shaft 9 is installed on the inner end surface of the right modulation end cover 3.2 through the third bearing 14.3; the radius of the inner circular surface of the boss is R pmi , the radius of the outer surface of the boss isR pmo , and satisfy the constraint relationship: 1.25≤ R pmo / R pmi ≤1.4; a plurality of pole-to-pole slots are arranged on the boss along the axis direction of the permanent magnet rotor 5, and the pole-to-pole slots are evenly arranged along the circumferential direction of the boss. The pole-to-pole slots are arranged in a V-shape, and the opening direction of the pole-to-pole slots is arranged outward. The angle between the through slots on both sides of the pole-to-pole slots meets 30º≤ θ pm ≤60º, and the bottom of the pole slots are not connected, the outer wall of the boss between the pole slot openings is set as the first rotor salient pole tooth 11.1, and the pole arc of the first rotor salient pole tooth 11.1 is θ 1 The outer wall of the boss between adjacent pairs of pole slots is set as the second rotor salient pole tooth 11.2, and the pole arc of the second rotor salient pole tooth 11.2 is θ 2 , and satisfy the constraints: 5º≤ θ 1 ≤7.5º, 5º≤ θ 2 ≤7.º and θ 1 ≠ θ 2 The top of the first rotor salient pole tooth 11.1 is connected to the top of the second rotor salient pole tooth 11.2 by a reinforcing rib 10, and the shape surrounded by the side wall of the top of the first rotor salient pole tooth 11.1, the side wall of the top of the second rotor salient pole tooth 11.2 and the outer wall of the reinforcing rib 10 is defined as a rotor virtual slot 7, and the pole arc of the rotor virtual slot 7 is θ d The permanent magnets 6 are respectively inserted into the corresponding pole slots, the number of the permanent magnets 6 is the same as the number of the rotor virtual slots 7, the two permanent magnets 6 inserted in each pole slot form a group of poles, the magnetization direction of the permanent magnets 6 in each group of poles is perpendicular to the long side of the permanent magnet and points to the inside of the pole slot opening, the gap between the top of each permanent magnet 6 and the corresponding reinforcement rib is set as the external magnetic barrier 8.1, and the gap between the bottom of each permanent magnet 6 and the bottom of the pole slot is set as the internal magnetic barrier 8.2.

[0020] Furthermore, the armature winding 2 adopts a single-layer distributed winding structure.

[0021] Furthermore, the number of pole pairs of the armature winding 2 is P s , the number of the magnetic tuning blocks 4 is N , the number of pole pairs of the permanent magnet 6 is P p , satisfying the relationship: N = Ps + P p .

[0022] Furthermore, the gap between the inner circumference of the stator 1 and the outer circumference of the modulation rotor 3 is 0.5 mm to 1 mm, and the gap between the inner circumference of the modulation rotor 3 and the outer circumference of the permanent magnet rotor 5 is 0.5 mm to 1 mm.

[0023] Furthermore, the radius of the outer wall of the stator 1 is R so , the radius of the inner wall of stator 1 is R si , the pole arc of stator pole shoe 1.1 is β p , the pole arc at the root of stator tooth 1.2 is β s , the pole arc at the end of stator tooth 1.2 is β t , the pole arc of the stator yoke 1.3 is β y In order to ensure the motor stator slot full rate and mechanical strength, the constraint relationship that needs to be satisfied is: 1.1≤ R so / R si ≤1.3; 2.5≤ β y / β s ≤3, 2≤ β p / β t ≤2.5.

[0024] Furthermore, there is a clearance fit between the permanent magnet rotor shaft 9 and the first shaft hole and the third shaft hole, and there is a clearance fit between the modulation rotor shaft 12 and the second shaft hole.

[0025] Furthermore, the thickness of the reinforcing rib 10 is 0.6 mm to 1.1 mm.

[0026] Furthermore, the stator 1, modulation rotor 3 and permanent magnet rotor 5 are made of stacked silicon steel sheets of the same thickness, the thickness of the silicon steel sheets is 0.35 mm, and the stacking coefficient is 0.95; the left modulation end cover 3.1, the right modulation end cover 3.2, the left stator end cover 13.1, the right stator end cover 13.2, the permanent magnet rotor shaft 9 and the modulation rotor shaft 12 are all made of non-magnetic materials; the material of each of the permanent magnets 6 is neodymium iron boron magnetic material.

[0027] Furthermore, the inner diameters of the second bearing 14.2, the third bearing 14.3 and the fourth bearing 14.4 are equal, and the inner diameter of the first bearing 14.1 is greater than the inner diameters of the second bearing 14.2, the third bearing 14.3 and the fourth bearing 14.4.

[0028] See also Figure 6 , the magnetic flux schematic diagram of the present invention when working, it can be seen that the permanent magnet 6 generates two parallel magnetic flux paths, namely the magnetic flux path a1 and the magnetic flux path b1. The magnetic flux path a1 passes through the first permanent magnet 6.1, the first rotor salient pole tooth 11.1, the inner air gap, the first modulation unit 4.1, the outer air gap, the stator pole shoe 1.1, the stator tooth 1.2, the stator yoke 1.3, the second modulation unit 4.2, the second rotor salient pole tooth 11.2 in sequence, and finally returns to the first permanent magnet 6.1; the magnetic flux path b1 passes through the second permanent magnet 6.2, the first rotor salient pole tooth 11.1, the inner air gap, the modulation unit 4.1, the outer air gap, the stator pole shoe 1.1, the stator tooth 1.2, the stator yoke 1.3, the modulation unit 4.2, the second rotor salient pole tooth 11.2 in sequence, and finally returns to the second permanent magnet 6.2. The magnetic flux paths a1 and b1 form a complete parallel magnetic circuit, so such a V-shaped permanent magnet 6 arrangement has a strong magnetic concentration effect, increases the utilization rate of the permanent magnets, improves the torque output capacity, and the magnetic barriers at the ends of the permanent magnets reduce leakage magnetic flux, further increasing the utilization rate of the permanent magnets.

[0029] The magnetic flux path of the present invention passes through two layers of air gaps during operation. Compared with the magnetic flux of the traditional dual-rotor permanent magnet motor (which needs to pass through three layers of air gaps), the permanent magnet magnetic field magnetic path is shorter and the magnetic resistance on the magnetic path is smaller, so the present invention has a higher torque output capacity and a higher power density. In addition, due to the unequal arc design of the salient pole teeth in the magnetic adjustment block 4 and the permanent magnet rotor 5, the magnetic field modulation effect is enhanced after the magnetic flux passes through these components, and more useful air gap magnetic field harmonics are generated in the air gap of the motor, further improving the output torque of the motor; at the same time, the targeted optimization design of the modulation unit and the permanent magnet rotor salient pole tooth unit can reduce the positioning torque of the motor, thereby reducing the torque pulsation of the motor.

[0030] Figure 7 The torque output waveform diagram of the motor under load of the present invention, wherein the horizontal axis is the electrical angle, the vertical axis is the output torque, and the output torque waveforms of the modulation rotor 3 and the permanent magnet rotor 5 are marked in the figure. It can be seen that based on the magnetic field modulation principle, through the targeted optimization design of the modulation rotor 3 and the permanent magnet rotor 5, the average output torque of the modulation rotor of the motor is 64Nm, and the average output torque of the permanent magnet rotor is 51Nm, and both rotors have a high output torque. At the same time, the torque pulsation of the modulation rotor 3 and the permanent magnet rotor 5 is less than 5%, and both rotors have low torque pulsation characteristics.

[0031] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A high torque density dual-rotor permanent magnet motor, comprising a stator (1), an armature winding (2), a modulation rotor (3), a permanent magnet rotor (5) and a stator housing (13), characterized in that: The stator (1), the modulation rotor (3) and the permanent magnet rotor (5) are coaxially arranged in a stator housing (13); the modulation rotor (3) is movably mounted in the stator (1); the permanent magnet rotor (5) is movably mounted in the modulation rotor (3); and gaps are arranged between the stator (1), the modulation rotor (3) and the permanent magnet rotor (5); A left stator end cover (13.1) and a right stator end cover (13.2) are respectively arranged at the left and right end surfaces of the stator housing (13); a first axial hole is arranged at the center of the left stator end cover (13.1); a second axial hole is arranged at the center of the right stator end cover (13.2); the first axial hole and the second axial hole are arranged coaxially; the stator (1) is fixedly mounted on the inner wall of the stator housing (13); the stator (1) comprises a stator pole shoe (1.1), stator teeth (1.2) and a stator A stator yoke (1.3) is provided, wherein a plurality of stator teeth (1.2) are evenly distributed on the inner circumferential surface of the stator (1), the roots of adjacent stator teeth (1.2) are connected via the stator yoke (1.3), an armature winding (2) is wound on the stator teeth (1.2), a stator pole shoe (1.1) is arranged at the end of the stator tooth (1.2), the outer walls of the plurality of stator yokes (1.3) are used as the outer walls of the stator (1), and the outer surfaces of the plurality of stator pole shoes (1.1) are used as the inner walls of the stator (1); The modulation rotor (3) comprises a left modulation end cover (3.1), a right modulation end cover (3.2) and a plurality of modulation magnetic blocks (4), the plurality of modulation magnetic blocks (4) being arranged with gaps in the circumferential direction, the plurality of modulation magnetic blocks (4) being of equal length, the head and tail ends of the modulation magnetic blocks (4) being respectively fixedly connected to the corresponding left modulation end cover (3.1) and right modulation end cover (3.2), the center of the left modulation end cover (3.1) being provided with a third axial hole, a sleeve being provided at the position of the third axial hole, the first axial hole, the third axial hole and the sleeve being arranged coaxially, the sleeve being inserted into the first axial hole, and a sleeve being provided between the sleeve and the first axial hole. A first bearing (14.1) is disposed; a modulation rotor shaft (12) is disposed at the center of the outer end surface of the right modulation end cover (3.2); the modulation rotor shaft (12) passes through the second shaft hole and extends to the outside of the stator housing (13); a fourth bearing (14.4) is disposed between the modulation rotor shaft (12) and the second shaft hole; the magnetic modulation block (4) comprises a plurality of first modulation units (4.1) and a plurality of second modulation units (4.2); the first modulation units (4.1) and the second modulation units (4.2) are arranged at intervals in the circumferential direction; the pole arc of the first modulation unit (4.1) is β m1 , the pole arc of the second modulation unit (4.2) is β m2 , the wall thickness of the first modulation unit (4.1) and the second modulation unit (4.2) are equal and satisfy the constraint condition: 7º≤ β m1 ≤12º, 7º≤ β m2 ≤12º, and β m1 ≠ β m2 The outer walls of the first modulation units (4.1) and the second modulation units (4.2) are used as the outer walls of the magnetic modulation block (4), the inner walls of the first modulation units (4.1) and the second modulation units (4.2) are used as the inner walls of the magnetic modulation block (4), and the radius of the outer wall of the modulation rotor (3) is R mo , the radius of the inner wall of the modulation rotor (3) is R mi , and satisfy the constraints: 1.10≤ R mo / R mi ≤1.15; The permanent magnet rotor (5) comprises a permanent magnet rotor shaft (9) and a boss, wherein the boss is arranged in the middle of the permanent magnet rotor (5) and close to one side of the right modulation end cover (3.2), one end of the permanent magnet rotor shaft (9) passes through the third shaft hole and the first shaft hole in sequence from the inside to the outside and extends to the outside of the stator housing (13), a second bearing (14.2) is arranged between the permanent magnet rotor shaft (9) and the third shaft hole, and the other end of the permanent magnet rotor shaft (9) is mounted on the inner end surface of the right modulation end cover (3.2) through the third bearing (14.3); the radius of the inner circular surface of the boss is R pmi , the radius of the outer surface of the boss is R pmo , and satisfy the constraint relationship: 1.25≤ R pmo / R pmi ≤1.4; a plurality of pole-to-pole slots are arranged on the boss along the axis direction of the permanent magnet rotor (5), the pole-to-pole slots are evenly arranged along the circumferential direction of the boss, the pole-to-pole slots are arranged in a V-shape, the opening direction of the pole-to-pole slots is arranged outward, and the angle between the through slots on both sides of the pole-to-pole slots satisfies 30º≤ θ pm ≤60º, and the bottom of the pole slots are not connected, the outer wall of the boss between the pole slot openings is set as the first rotor salient pole tooth (11.1), and the pole arc of the first rotor salient pole tooth (11.1) is θ 1 The outer wall of the boss between adjacent pole slots is set as a second rotor salient pole tooth (11.2), and the pole arc of the second rotor salient pole tooth (11.2) is θ 2 , and satisfy the constraints: 5º≤ θ 1 ≤7.5º, 5º≤ θ 2 ≤7.º and θ 1 ≠ θ 2 The top of the first rotor salient pole tooth (11.1) and the top of the second rotor salient pole tooth (11.2) are connected via a reinforcing rib (10), and a shape enclosed by the side wall of the top of the first rotor salient pole tooth (11.1), the side wall of the top of the second rotor salient pole tooth (11.2) and the outer wall of the reinforcing rib (10) is defined as a rotor virtual slot (7), and the pole arc of the rotor virtual slot (7) is θ d The permanent magnets (6) are respectively inserted into the corresponding pole slots, the number of the permanent magnets (6) is the same as the number of the rotor virtual slots (7), the two permanent magnets (6) inserted into each pole slot form a group of poles, the magnetization direction of the permanent magnets (6) in each group of poles is perpendicular to the long side of the permanent magnet and points to the inside of the pole slot opening, the gap between the top of each permanent magnet (6) and the corresponding reinforcing rib is set as the external magnetic barrier (8.1), and the gap between the bottom of each permanent magnet (6) and the bottom of the pole slot is set as the internal magnetic barrier (8.2).

2. A high torque density dual-rotor permanent magnet motor according to claim 1, characterized in that: The armature winding (2) adopts a single-layer distributed winding structure.

3. A high torque density dual-rotor permanent magnet motor according to claim 2, characterized in that: The number of pole pairs of the armature winding (2) is P s , the number of the magnetic tuning blocks (4) is N , the number of pole pairs of the permanent magnet (6) is P p , satisfying the relationship: N = P s + P p .

4. The high torque density dual-rotor permanent magnet motor according to claim 1, characterized in that: The gap between the inner circumferential surface of the stator (1) and the outer circumferential surface of the modulation rotor (3) is 0.5 mm to 1 mm, and the gap between the inner circumferential surface of the modulation rotor (3) and the outer circumferential surface of the permanent magnet rotor (5) is 0.5 mm to 1 mm.

5. The high torque density dual-rotor permanent magnet motor according to claim 1, characterized in that: The radius of the outer wall of the stator (1) is R so , the radius of the inner wall of the stator (1) is R si , the pole arc of the stator pole shoe (1.1) is β p , the pole arc at the root of the stator tooth (1.2) is β s , the pole arc at the end of the stator tooth (1.2) is β t , the pole arc of the stator yoke (1.3) is β y , the constraints that need to be satisfied are: 1.1≤ R so / R si ≤1.3; 2.5≤ β y / β s ≤3, 2≤ β p / β t ≤2.

5.

6. The high torque density dual-rotor permanent magnet motor according to claim 1, characterized in that: There is a clearance fit between the permanent magnet rotor shaft (9) and the first shaft hole and the third shaft hole, and there is a clearance fit between the modulation rotor shaft (12) and the second shaft hole.

7. The high torque density dual-rotor permanent magnet motor according to claim 1, characterized in that: The thickness of the reinforcing rib (10) is 0.6 mm to 1.1 mm.

8. The high torque density dual-rotor permanent magnet motor according to claim 1, characterized in that: The stator (1), the modulation rotor (3) and the permanent magnet rotor (5) are formed by stacking silicon steel sheets of the same thickness, the thickness of the silicon steel sheets is 0.35 mm, and the stacking coefficient is 0.95; the left modulation end cover (3.1), the right modulation end cover (3.2), the left stator end cover (13.1), the right stator end cover (13.2), the permanent magnet rotor shaft (9) and the modulation rotor shaft (12) are all made of non-magnetic conductive materials; and the material of each of the permanent magnets (6) is neodymium iron boron magnetic material.

9. The high torque density dual-rotor permanent magnet motor according to claim 1, characterized in that: The inner diameters of the second bearing (14.2), the third bearing (14.3) and the fourth bearing (14.4) are equal, and the inner diameter of the first bearing (14.1) is greater than the inner diameters of the second bearing (14.2), the third bearing (14.3) and the fourth bearing (14.4).

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