A Halbach array hybrid permanent magnet stator dual-partition motor

Abstract

The invention relates to the technical field of motors, and discloses a Halbach array hybrid permanent magnet stator double-zone motor, comprising an inner zone stator, an intermediate rotor and an outer zone stator arranged concentrically. The inner zone stator comprises an inner zone stator core, a NdFeB+AlNiCo hybrid permanent magnet and a pulse magnetization winding wound on the AlNiCo permanent magnet, and the NdFeB and AlNiCo permanent magnets are alternately placed on the outer side of the inner zone stator core along the circumference in a Halbach array. The cylindrical intermediate rotor is alternately placed along the circumference by magnetic conductive blocks and insulating blocks; the outer zone stator comprises an outer zone stator core and an armature winding arranged on the outer zone stator core; the outer zone stator core comprises an outer zone stator yoke and outer zone stator teeth protruding from the inner side of the outer zone stator yoke and uniformly distributed along the circumference, and each outer zone stator tooth is wound with a concentrated armature coil. Compared with the prior art, the present invention can realize low-speed high torque, high-speed wide speed regulation and high efficiency performance of the motor on the basis of realizing magnetization and weak magnetic field regulation of the stator partition motor, and is suitable for the field of electric vehicles.

Description

Technical Field

[0001] The invention relates to the technical field of motor body design, and in particular to a Halbach array hybrid permanent magnet stator double-partition motor. Background Art

[0002] As a key component of electric vehicles, the performance of the motor has a significant impact on the entire drive system. According to the application characteristics of electric vehicles, its drive motor should have a large torque output capacity, high efficiency and a wide speed regulation range.

[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 and permanent magnets on the rotor. The windings and permanent magnets are all 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 are made: 1. Output torque: The space for placing the windings is reduced, which limits the further improvement of the motor's torque output capacity. 2. Motor installation: Since the stator core of the permanent magnet flux switching motor and the double salient pole stator permanent magnet motor is composed of multiple discrete pieces, the difficulty of motor processing and installation is increased. 3. Other performance: The stator magnetic field saturation of the stator permanent magnet motor is relatively large, which reduces the motor overload capacity, and the structure will increase the temperature rise of the windings and permanent magnets on the stator, which will cause winding insulation damage and irreversible demagnetization of the permanent magnets in severe cases.

[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 the rotor in the stator partitioned permanent magnet motor, its air gap flux density and output torque under equal electrical load are weakened compared with the original single-gap stator permanent magnet 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 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 Halbach array hybrid permanent magnet stator double-partition motor structure with high torque density and high efficiency, which improves the no-load air gap magnetic flux density of the conventional stator partitioned permanent magnet motor and is suitable for the field of electric vehicle driving.

[0007] Technical solution: The present invention provides a Halbach array hybrid permanent magnet 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 includes an inner stator core, a permanent magnet disposed on the outer wall of the inner stator core, and a pulse magnetization winding disposed on the permanent magnet; the intermediate rotor includes magnetic conductive blocks and insulating blocks arranged alternately along the circumferential direction; the outer stator includes an outer stator core and a pulse magnetization winding disposed on the outer stator core. m Phase armature winding;

[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 stator core includes an outer stator yoke and P s The outer stator teeth protrude uniformly along the inner circumference of the outer stator yoke, and an outer stator slot is formed between any two adjacent outer stator teeth. m The phase armature windings are distributed in the 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.

[0012] Furthermore, the intermediate rotor is composed of q Block magnetic block and q The insulating blocks are arranged alternately along the circumference and meet 2q = P s ±2 k ,in k Is a positive integer.

[0013] Furthermore, the permanent magnets arranged on the outer wall of the inner zone stator core include sector ring-shaped NdFeB permanent magnets and sector ring-shaped AlNiCo permanent magnets and are arranged in a Halbach array; the outer circumference of the inner zone stator core is evenly arranged. P s The inner arc surface of the NdFeB permanent magnet is tightly fitted with the outer ring of the inner stator core. P s The NdFeB permanent magnets are not directly connected in the circumferential direction, forming a sector ring gap, in which the sector ring AlNiCo permanent magnet is embedded, and the two side surfaces of the sector ring AlNiCo permanent magnet are closely fitted with the two side surfaces of the NdFeB permanent magnet.

[0014] Furthermore, the radial inner diameter of the fan-shaped alnico permanent magnet is larger than the radial inner diameter of the fan-shaped neodymium iron boron permanent magnet, and the radial outer diameter of the fan-shaped alnico permanent magnet is smaller than the radial outer diameter of the fan-shaped neodymium iron boron permanent magnet; two inner-zone stator slots are formed on radial sides of each alnico permanent magnet, and the pulse magnetization winding is placed in the inner-zone stator slots and wound around the alnico permanent magnet.

[0015] Furthermore, the NdFeB permanent magnet is made of rare earth NdFeB permanent magnet material. P s The magnetization direction of the block NdFeB permanent magnet changes alternately along the radial direction, and its radial center line coincides with the radial center line of the outer zone stator teeth.

[0016] Furthermore, the AlNiCo permanent magnet is made of AlNiCo permanent magnet material. P s The magnetization direction of the AlNiCo permanent magnet changes alternately along the tangential direction, and its radial center line coincides with the radial center line of the stator slot in the outer zone.

[0017] Furthermore, the pulse magnetization winding is a concentrated winding, and the multiple pulse magnetization winding concentrated winding coils are connected in series to form a single-phase pulse winding, and a short-time pulse current is applied thereto.

[0018] Beneficial effects:

[0019] 1. Based on the conventional stator partitioned motor structure, the present invention adopts a Halbach array permanent magnet structure including NdFeB permanent magnets and AlNiCo permanent magnets on the inner zone stator. By utilizing the magnetic concentration and weak magnetic effects of the Halbach array permanent magnet structure and the characteristics that AlNiCo permanent magnets can be charged and demagnetized by short-time pulse current and "memorize" their magnetic density, it can be achieved that: when running in magnetic concentration mode at low speed, the AlNiCo permanent magnet is fully positively magnetized, the main magnetic field of the air gap outside the permanent magnet is enhanced, and the magnetic field of the inner air gap is weakened, not only It can improve the air gap flux density and torque output capacity of the motor, and reduce the iron loss of the inner stator core, thereby increasing the efficiency of the motor when running at low speed; when running at high speed, it runs in weak magnetic field mode, at which time the AlNiCo permanent magnet is completely reversely magnetized, the air gap magnetic field inside the permanent magnet is enhanced, and the main magnetic field of the air gap outside is weakened, which not only reduces the air gap flux density and increases the speed regulation range of the motor, but also reduces the weak magnetic field current and the corresponding copper loss due to the weakening of the permanent magnet magnetic field, thereby improving the efficiency of the motor when running at high speed.

[0020] 2. Since the motor of the present invention adopts a stator permanent magnet structure, the NdFeB permanent magnet, AlNiCo permanent magnet and pulse magnetization winding are all placed on the inner zone stator, while the armature winding is placed on the outer zone stator, thus achieving the separation of the armature winding and the permanent magnet, making it easier to dissipate heat and cool the motor.

[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 It is a schematic diagram of the radial cross-section structure of the Halbach array hybrid permanent magnet stator double-partition 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 It is a schematic diagram of the inner stator when the AlNiCo permanent magnet is forward magnetized in the present invention;

[0025] Figure 4 It is a schematic diagram of the inner stator when the AlNiCo permanent magnet is reversely magnetized in the present invention;

[0026] Figure 5 (a) is the principle diagram of permanent magnetic field "magnetization" when AlNiCo permanent magnet is forward magnetized; Figure 5 (b) is the principle diagram of the permanent magnetic field "weak magnetic field" when the AlNiCo permanent magnet is reversely magnetized;

[0027] Figure 6 (a) is the no-load magnetic field distribution of the motor when the AlNiCo permanent magnet is forward magnetized by finite element simulation; Figure 6(b) is the no-load magnetic field distribution of the motor when the AlNiCo permanent magnet is reversely magnetized by finite element simulation;

[0028] Figure 7 (a) and (b) are the finite element simulation of the internal and external air gap flux density waveforms of the motor when the AlNiCo permanent magnet is forward magnetized; Figure 7 (c) and (d) are the finite element simulation of the internal and external air gap flux density waveforms of the motor when the AlNiCo permanent magnet is reversely magnetized.

[0029] Among them: 1. outer zone stator, 1-1. outer zone stator core, 1-2. armature winding, 1-3. outer zone stator yoke, 1-4. outer zone stator teeth, 1-5. outer zone stator slots, 2. intermediate rotor, 2-1. magnetic conductive block, 2-2. insulating block, 3. inner zone stator, 3-1. inner zone stator core, 3-2. neodymium iron boron permanent magnet, 3-3. aluminum nickel cobalt permanent magnet, 3-4. pulse magnetization winding, 3-5 inner zone stator slots. 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 12 slots / intermediate rotor 10 poles / inner zone stator 12 poles stator partition motor as an example, the technical solution of the present invention is specifically described.

[0032] The motor of the present invention comprises an inner stator 3 arranged concentrically, an intermediate rotor 2 surrounding the inner stator 3, and an outer stator 1 surrounding the intermediate rotor 2. Figure 1 As shown, 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 .

[0033] The inner stator 3 includes an inner stator core 3-1, a permanent magnet and a pulse magnetization winding 3-4 arranged on the inner stator core, the intermediate rotor 2 includes a rotor support, a magnetic conductive block 2-1 and an insulating block 2-2, and the outer stator 1 includes an outer stator core 1-1 and a permanent magnet and a pulse magnetization winding 3-4 arranged on the outer stator core 1-1. m The phase armature winding 1-2; the inner partition stator 3 and the outer partition stator 1 are fixedly connected to the motor housing, and the intermediate rotor 2 is fixedly connected to the motor output shaft through a rotor bracket.

[0034] See also Figure 2 The outer stator core 1-1 includes an outer stator yoke 1-3 and P s The outer stator teeth 1-4 protrude uniformly along the inner circumference of the outer stator yoke 1-3, and an outer stator slot 1-5 is formed between any two adjacent outer stator teeth 1-4. m Phase armature winding 1-2 is distributed in the Ps In the outer stator slots 1-5, and the m Phase armature windings 1-2 are wound on outer stator teeth 1-4 respectively, satisfying P s =6 n ,in n Is a positive integer.

[0035] The intermediate rotor 2 is q Block magnetic block 2-1 and q The insulating blocks 2-2 are arranged alternately along the circumferential direction and satisfy 2 q = P s ±2 k ,in k Is a positive integer.

[0036] See also Figure 3 and Figure 4 The inner stator core 3-1 is annular, and the outer ring of the inner stator core 3-1 is evenly placed along the circumference. P s The block sector annular NdFeB permanent magnet 3-2 has an inner arc surface that is tightly fitted with the outer ring of the inner zone stator core 3-1. P s The NdFeB permanent magnets 3-2 are not directly connected in the circumferential direction, forming a sector-shaped annular gap, in which the sector-shaped annular AlNiCo permanent magnets 3-3 are embedded. The two sides of the sector-shaped annular AlNiCo permanent magnets 3-3 are tightly fitted with the NdFeB permanent magnets 3-2, the radial inner diameter of the sector-shaped annular AlNiCo permanent magnets 3-3 is larger than the radial inner diameter of the sector-shaped annular NdFeB permanent magnets 3-2, and the radial outer diameter of the sector-shaped annular AlNiCo permanent magnets 3-3 is smaller than the radial outer diameter of the sector-shaped annular NdFeB permanent magnets 3-2. Two inner stator slots 3-5 are formed on both radial sides of each AlNiCo permanent magnet 3-3, and pulse magnetization windings 3-4 are placed in the inner stator slots 3-5 and wound around the AlNiCo permanent magnets 3-3.

[0037] NdFeB permanent magnet 3-2 is made of rare earth NdFeB permanent magnet material. P s The magnetization direction of the block NdFeB permanent magnet 3-2 changes alternately along the radial direction, and its center line is aligned with the center line of the outer stator teeth 1-4, and the two are on the same straight line. The AlNiCo permanent magnet 3-3 is made of AlNiCo permanent magnet material. P s The magnetization direction of the AlNiCo permanent magnet 3-3 changes alternately along the tangential direction, and its center line is aligned with the center line of the outer stator slot 1-5, and the two are on the same straight line. Since the AlNiCo permanent magnet material has the characteristics of low coercive force, it adopts the casting manufacturing process, has high temperature stability, can be charged and demagnetized by short-time pulse current, and "memorizes" its magnetic density level, which can realize the flexible adjustment of the motor air gap magnetic density.

[0038] The pulse magnetization winding 3-4 is a concentrated winding. P s The pulse magnetization winding 3-4 concentrated winding coils are connected in series to form a single-phase pulse winding, and the pulse winding applies a short-time pulse current to change the magnetization level and magnetization direction of the AlNiCo permanent magnet 3-3 to adjust the air gap magnetic field of the motor. Figure 3 The figure shows the magnetization direction of the permanent magnet on the inner stator when the AlNiCo permanent magnet 3-3 is positively magnetized by a short-time pulse current. Figure 4 The figure shows the schematic diagram of the magnetization direction of the permanent magnet on the inner stator when the AlNiCo permanent magnet 3-3 is reversely magnetized by a short-time pulse current.

[0039] See also Figure 5 This is a schematic diagram of the magnetic field regulation principle of the motor of the present invention, wherein the direction of the magnetic flux generated by the AlNiCo permanent magnet 3-3 is represented by a dotted line, and the magnetic flux generated by the NdFeB permanent magnet 3-2 is represented by a solid line.

[0040] like Figure 5 (a) is the "low-speed magnetization and torque increase" mode. At this time, the AlNiCo permanent magnet 3-3 is fully forward magnetized. The magnetic flux generated by the AlNiCo permanent magnet 3-3 and the NdFeB permanent magnet 3-2 has the same direction when passing through the main magnetic circuit formed by the inner and outer air gaps, the magnetic conductive block 2-1 of the intermediate rotor 2 and the outer stator core 1-1 on the outside of the permanent magnet, and the direction is opposite when flowing through the inner stator core 3-1 on the inside of the permanent magnet. Therefore, the magnetic fields of the AlNiCo permanent magnet 3-3 and the NdFeB permanent magnet 3-2 on the outside of the permanent magnet are superimposed on each other to achieve main magnetic field magnetization, and weaken each other on the inside of the permanent magnet to achieve weak magnetic field. At this time, the motor has a larger air gap magnetic density, which is suitable for low-speed and high-torque conditions. At the same time, it reduces the iron loss of the inner stator and improves the efficiency of the motor when running at low speed.

[0041] Figure 5 (b) shows the "high-speed weak magnetic speed regulation" mode, at which the AlNiCo permanent magnet 3-3 is completely reversely magnetized, and the magnetic flux generated by the AlNiCo permanent magnet 3-3 and the NdFeB permanent magnet 3-2 is in opposite directions when passing through the main magnetic circuit formed by the inner and outer air gaps, the intermediate rotor magnetic block 2-1 and the outer stator core 1-1 on the outside of the permanent magnet, while the directions are the same when flowing through the inner stator core 3-1 on the inside of the permanent magnet. Therefore, the main magnetic fields of the AlNiCo permanent magnet 3-3 and the NdFeB permanent magnet 3-2 on the outside of the permanent magnet weaken each other to achieve weak magnetic field, thereby achieving the purpose of widening the speed regulation range of the motor, and because the magnetic field is weakened by adjusting the permanent magnetic field, the weak magnetic current and the corresponding copper loss are reduced, thereby improving the efficiency of the motor during high-speed operation.

[0042] Figure 6 and Figure 7 The figure shows the no-load magnetic field distribution of the motor of the present invention when the AlNiCo permanent magnet 3-3 is fully forwardly and reversely magnetized as simulated by finite element. Figure 6 (a) and Figure 6 (b) The magnetic field line distribution diagram is respectively Figure 5 (a) and Figure 5 (b) is consistent with the magnetic field distribution principle diagram, Figure 7 (a) Figure 7 (b) Figure 7 (c) and Figure 7 (d) shows the significant changes in the inner and outer air gap magnetic flux density when the AlNiCo permanent magnet 3-3 is fully forwardly and reversely magnetized, indicating that the motor of the present invention has strong magnetization and magnetic weakening capabilities, can achieve the performance requirements of low speed and high torque, high speed and wide speed regulation range and high efficiency, and is suitable for the field of electric vehicles.

[0043] 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 Halbach array hybrid permanent magnet 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 (3-1), a permanent magnet disposed on the outer wall of the inner region stator core (3-1), and a pulse magnetization winding (3-4) disposed on the permanent magnet; the intermediate rotor (2) comprises magnetic conductive blocks (2-1) and insulating blocks (2-2) arranged alternately along the circumferential direction; the outer region stator (1) comprises an outer region stator core (1-1) and a pulse magnetization winding (3-4) disposed on the outer region stator core (1-1); m phase armature winding (1-2); the outer region stator core (1-1) comprises an outer region stator yoke (1-3) and P s outer region stator teeth (1-4) protruding uniformly along the inner circumference of the outer region stator yoke (1-3); The intermediate rotor (2) is composed of q Block magnetic block (2-1) and q The insulating blocks (2-2) are arranged alternately along the circumferential direction and satisfy 2 q = P s ±2 k ,in k is a positive integer; 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 permanent magnets arranged on the outer wall of the inner zone stator core (3-1) include sector ring-shaped NdFeB permanent magnets (3-2) and sector ring-shaped AlNiCo permanent magnets (3-3) arranged in a Halbach array; the outer circumference of the inner zone stator core (3-1) is evenly arranged. P s A block-sector annular NdFeB permanent magnet (3-2), wherein the inner arc surface of the NdFeB permanent magnet (3-2) is tightly fitted with the outer ring of the inner stator core (3-1). P s The NdFeB permanent magnets (3-2) are not directly connected in the circumferential direction, forming a sector-shaped annular gap, in which the sector-shaped annular AlNiCo permanent magnet (3-3) is embedded, and the two side surfaces of the sector-shaped annular AlNiCo permanent magnet (3-3) are respectively tightly fitted with the two side surfaces of the NdFeB permanent magnet (3-2); The radial inner diameter of the sector-shaped annular AlNiCo permanent magnet (3-3) is larger than the radial inner diameter of the sector-shaped annular NdFeB permanent magnet (3-2), and the radial outer diameter of the sector-shaped annular AlNiCo permanent magnet (3-3) is smaller than the radial outer diameter of the sector-shaped annular NdFeB permanent magnet (3-2); two inner-zone stator slots (3-5) are formed on radial sides of each AlNiCo permanent magnet (3-3), and the pulse magnetization winding (3-4) is placed in the inner-zone stator slots (3-5) and is wound around the AlNiCo permanent magnet (3-3); The NdFeB permanent magnet (3-2) is made of rare earth NdFeB permanent magnet material. P s The magnetization direction of the block NdFeB permanent magnet (3-2) changes alternately in the radial direction, and its radial center line is aligned with the radial center line of the outer zone stator teeth (1-4); The AlNiCo permanent magnet (3-3) is made of AlNiCo permanent magnet material. P s The magnetization direction of the AlNiCo permanent magnet (3-3) changes alternately along the tangential direction, and its radial center line is aligned with the radial center line of the outer zone stator slot (1-5).

2. The Halbach array hybrid permanent magnet stator dual-partition motor according to claim 1, characterized in that: An outer zone stator slot (1-5) is formed between any two adjacent outer zone stator teeth (1-4), wherein m Phase armature winding (1-2) is distributed in P s The outer region stator slots (1-5) are wound on the outer region stator teeth (1-4), satisfying P s =6 n ,in n Is a positive integer.

3. The Halbach array hybrid permanent magnet stator dual-partition motor according to claim 1 or 2, characterized in that: The pulse magnetization winding (3-4) is a concentrated winding, and a plurality of concentrated winding coils of the pulse magnetization winding (3-4) are connected in series to form a single-phase pulse winding, and a short-time pulse current is applied thereto.

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