Brushless dual-rotor motor structure for vehicles

Abstract

The present invention relates to the field of motor technology, and discloses a brushless dual-rotor motor structure for a vehicle, which is composed of two motors with radial magnetic circuit structures, including an inner motor component composed of an inner rotor (inner rotor core unit, inner rotor permanent magnet), a modulating rotor, an inner stator (inner stator core unit and inner stator winding); and an outer motor component composed of an outer stator (outer stator winding, outer stator core unit, outer stator permanent magnet) and an outer rotor; the modulating rotor is connected to the input shaft and rotates therewith, the inner and outer rotors are rigidly connected to the output shaft and rotate together with the output shaft, and the inner and outer stators are separated by stator magnetic isolation and fixed on the motor housing. Compared with the prior art, the present invention can be applied to the field of hybrid electric vehicles, can realize the brushless dual-rotor motor, and has reliable operation. Through the control of the inner and outer motors, the power requirements of different working conditions can be met.

Description

Technical Field

[0001] The invention belongs to the field of motor design, in particular to a brushless dual-rotor motor structure applied to a hybrid electric vehicle. Background Art

[0002] With the development of hybrid electric vehicles (HEV), electromagnetic transmission hybrid power systems using dual-rotor drive motors have been proposed and received attention. Compared with traditional automobile drive systems, electromagnetic transmission hybrid power systems can achieve high-efficiency continuously variable power coupling and have high fuel economy; compared with mechanical transmission hybrid power systems using planetary gears, electromagnetic transmission hybrid power systems have a compact structure, and the dual-rotor drive motors can replace the starter / generator and electric motor to achieve hybrid power coupling and distribution. Therefore, this system has become one of the development directions of hybrid power systems.

[0003] The dual-rotor motor structure proposed in the Chinese invention patent application No. 201310412708.3 and 201510755061.3 is composed of two inner and outer motors radially integrated in the order of "outer stator-intermediate rotor-inner rotor-rotating shaft". Windings are provided on both the inner rotor and the outer stator to form the dual electrical channels of the dual-rotor motor; the inner rotor is connected to the engine, the intermediate rotor is connected to the load, and the inner rotor and the intermediate rotor form the dual mechanical channels of the dual-rotor motor. The dual electrical channels and the dual mechanical channels form a four-port motor structure. Applied in hybrid power systems, the dual-rotor motor can achieve energy distribution and coupling between the mechanical energy output by the engine and the electrical energy output by the energy storage device under different working conditions through the speed regulation of the inner motor and the torque regulation of the outer motor, thereby reducing fuel consumption while improving the operating efficiency of the engine and the system, and achieving energy conservation and emission reduction. However, since the inner rotor of the dual-rotor motor is often in a rotating state, the current connected to the winding on the inner rotor needs to be transmitted through brushes. The speed of the inner rotor in the hybrid system is usually relatively high. The dust and sparks brought by the brushes pose a great safety hazard to the operation of the system. Therefore, the brushless dual-rotor motor has become a major research hotspot. Summary of the invention

[0004] Purpose of the invention: In view of the problems existing in the prior art, the present invention proposes a brushless dual-rotor motor structure for hybrid electric vehicles to overcome the problems of insufficient operating efficiency, low reliability and large brush maintenance workload of brushed dual-rotor motors.

[0005] Technical solution: The present invention provides a brushless dual-rotor motor structure for a vehicle, comprising an input shaft, an output shaft coaxially arranged with the input shaft, an inner rotor core unit surrounding the output shaft, an inner rotor permanent magnet surrounding the inner rotor core unit, a modulation rotor surrounding the inner rotor permanent magnet, an inner stator core unit surrounding the modulation rotor, a stator magnetic shield surrounding the inner stator core unit, an outer stator core unit surrounding the stator magnetic shield, an outer stator permanent magnet surrounding the outer stator core unit, and an outer rotor 7 surrounding the outer stator permanent magnet;

[0006] Air gaps are provided between the inner rotor permanent magnet and the modulation rotor, between the modulation rotor and the inner stator core unit, between the outer stator core unit and the outer stator permanent magnet, and between the outer stator permanent magnet and the outer rotor. The inner rotor permanent magnet is composed of 2n radially alternately magnetized permanent magnet units uniformly distributed along the circumference, where n is a positive integer.

[0007] The inner rotor core unit is fixed on the output shaft, the inner rotor permanent magnet is fixed on the inner rotor core unit, and the radial inner and outer side walls of the stator magnetic isolation are respectively fixedly connected to the outer side wall of the inner stator core unit and the inner side wall of the outer stator core unit.

[0008] Furthermore, the modulation rotor is fixedly connected to the input shaft through a modulation rotor bracket, and is rotatably connected to the output shaft; the inner stator core unit, stator magnetic shield, outer stator core unit, and outer stator permanent magnet constitute a stator unit, which is fixedly connected to a motor housing through a stator bracket, and is rotatably connected to the output shaft; the outer rotor is fixedly connected to the output shaft through an outer rotor bracket, and is rotatably connected to the motor housing; the motor housing is rotatably connected to the input shaft and the output shaft, respectively.

[0009] Furthermore, the outer stator core unit is in a circular ring shape, and a plurality of slots are opened axially on its outer surface, the openings of the plurality of slots point to the outer rotor and the center lines of the slot openings are evenly distributed along the circumference, and the plurality of slots are respectively embedded with the outer stator windings to form an m-phase winding. When an m-phase symmetrical alternating current is passed, a rotating magnetic field with a pole number of 2p is formed, and m and p are both positive integers.

[0010] Furthermore, the inner stator core unit is annular, and a plurality of slots are opened in the axial direction on the inner surface of the inner circle, and the opening center lines of the plurality of slots are evenly distributed around the circumference of the shaft, and the plurality of slots are respectively embedded with the inner stator winding to form m 1 Phase winding, pass m 1 When the alternating current is symmetrical, a 2p 1 Rotating magnetic field with number of poles, m 1 、p 1 All are positive integers.

[0011] Furthermore, the inner rotor core unit is in a circular ring shape, the inner rotor permanent magnet is embedded in the inner rotor core unit or fixed on its outer circular surface, the inner rotor core unit and the inner rotor permanent magnet constitute the inner rotor, and when the inner rotor rotates, an inner rotor surface magnetic field with a pole number of 2n is formed.

[0012] Furthermore, the modulation rotor is in the shape of a ring and is composed of q magnetic conductive blocks 3 - 1 and q insulating blocks which are staggered along the circumference, wherein q is a positive integer.

[0013] Furthermore, the n, q, p 1 Satisfy p 1 =|hn+kq|, where h is a positive odd number and k is a positive integer.

[0014] Furthermore, the outer rotor adopts a salient pole structure, and its radial inner rotating poles are evenly distributed on the circumference.

[0015] Furthermore, the inner rotor permanent magnet adopts a surface-mounted Halbach permanent magnet structure, and the outer stator partition permanent magnet 6-2 adopts a radial alternating magnetization method.

[0016] Beneficial effects:

[0017] 1. The present invention is a brushless structure. Since the winding on the stator does not need to rotate, it overcomes the problems of reduced operating efficiency, reduced reliability, and frequent maintenance of brushes and other components caused by the use of a brush slip ring feeding structure for the armature winding on the rotating inner rotor in a conventional dual-rotor motor.

[0018] 2. The motor of the present invention has two rotating shafts. The modulating rotor is connected to the engine through the input rotating shaft to receive the mechanical power output by the engine. The inner rotor and the outer rotor are connected to the load through the output rotating shaft to drive the load to run at a certain output speed and torque. The speeds of the two rotating shafts are independent of each other. In the permanent magnet modulating inner motor, when the speed of the modulating rotor is equal to the speed of the engine and runs in the high-speed range of the high-efficiency interval, the speed of the inner rotor is adjustable and it is in a certain proportional relationship with the torque of the modulating rotor, so that the modulating rotor connected to the input rotating shaft runs at a high speed and low torque, and the output rotating shaft connected to the inner rotor runs at a lower speed and larger torque. When the output power of the generator and the inner motor meets the load demand, the outer rotor and the output rotating shaft in the outer motor rotate at the same speed, and the winding on the outer stator generates electric power through electromagnetic induction, which can be charged to the energy storage device through rectification; when the output torque of the inner motor is not enough to drive the load to run, the outer stator in the outer motor is fed with current through the battery, and the electromechanical energy conversion of the outer motor finally makes up for the lack of output torque on the outer rotor and its connected output rotating shaft.

[0019] 3. In the present invention, the inner and outer stators are connected radially by non-magnetic stators to reduce the magnetic field coupling of the inner and outer motors, so the inner and outer motors can be controlled independently, simplifying the control method of the dual-rotor motor. In order to realize the brushless structure, the inner motor adopts a double-layer air gap permanent magnetic field modulation motor structure, and further adopts a Halbach permanent magnet on the inner rotor. On the one hand, the air gap magnetic density and torque output capacity are increased to make up for the permanent magnetic field weakened by the double air gap; on the other hand, the iron loss of the inner motor is reduced, and the efficiency and power factor of the motor are improved. The stator partition permanent magnet motor structure is adopted in the outer motor, and the permanent magnet originally placed on the stator is separated from the stator core and placed between the circumferential air gaps of the outer stator and the outer rotor. On the one hand, the winding space is increased and the torque output capacity of the motor is improved; on the other hand, the stator permanent magnet motor overcomes the high temperature rise caused by the armature winding and the permanent magnet being located on the stator, which causes the winding insulation damage and the permanent magnet being easy to have irreversible demagnetization. Therefore, the stator partition outer motor improves the reliability of the motor operation.

[0020] 4. The present invention is applied to hybrid power systems, can achieve stepless speed change, and can replace clutches, gearboxes, starters and generators; compared with existing dual-rotor motors, it is brushless and has the advantages of reliable operation, wide speed regulation range, good starting performance and high power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A cross-sectional view of the brushless dual-rotor motor structure proposed by the present invention;

[0022] Figure 2 (a) and Figure 2 (b) Schematic diagrams of the structures of the permanent magnet magnetic field modulation inner motor and the stator permanent magnet partition outer motor respectively;

[0023] Figure 3 It is a schematic diagram of the magnetization direction of the permanent magnets of the inner and outer motors;

[0024] Figure 4 This is a schematic diagram of the structure of a brushless dual-rotor motor for a hybrid vehicle of the present invention;

[0025] Figure 5 This is a structural diagram of the brushless dual-rotor motor HEV drive system proposed in the present invention.

[0026] 1-1 output shaft, 1-2 input shaft, 2 inner rotor, 2-1 inner rotor core unit, 2-2 inner rotor permanent magnet, 3 modulation rotor, 3-1 magnetic conductive block, 3-2 insulating block, 4 inner stator, 4-1 inner stator core unit, 4-2 inner stator winding, 5 stator magnetic isolation, 6 outer stator, 6-1 outer stator core unit, 6-2 outer stator winding, 6-3 outer stator permanent magnet, 7 outer rotor, 8 stator unit, 9 modulation rotor bracket, 10 first bearing, 11 second bearing, 12 stator bracket, 13 motor housing, 14 third bearing, 15 outer rotor bracket, 16 fourth bearing, 17 fifth bearing, 18 sixth bearing, 19 brushless dual-rotor motor, 20 engine, 21 power converter, 22 energy storage device, 23 wheels, 24 power socket. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with the accompanying drawings.

[0028] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Below Figure 1The radial magnetic field brushless dual-rotor motor shown is taken as an example to specifically illustrate the technical solution of the present invention.

[0032] The present invention relates to the technical field of motors, and discloses a brushless dual-rotor motor, comprising a motor housing 13, an input shaft 1-2, a coaxially arranged output shaft 1-1, an inner rotor core unit 2-1 surrounding the output shaft 1-1, an inner rotor permanent magnet 2-2 surrounding the inner rotor core unit 2-1, a modulation rotor 3 surrounding the inner rotor permanent magnet 2-2, an inner stator core unit 4-1 surrounding the modulation rotor 3, a stator magnetic shield 5 surrounding the inner stator core unit 4-1, an outer stator core unit 6-1 surrounding the stator magnetic shield 5, an outer stator permanent magnet 6-3 surrounding the outer stator core unit 6-1, and an outer rotor 7 surrounding the outer stator permanent magnet 6-3.

[0033] In this embodiment, air gaps are provided between the inner rotor permanent magnet 2-2 and the modulation rotor 3, between the modulation rotor 3 and the inner stator core unit 4-1, between the outer stator core unit 6-1 and the outer stator permanent magnet 6-3, and between the outer stator permanent magnet 6-3 and the outer rotor 7. The inner rotor core unit 2-1 is fixedly connected to the output shaft 1-1, the inner rotor permanent magnet 2-2 is fixed to the inner rotor core unit 2-1, and the radial inner and outer side walls of the stator magnetic shield 5 are fixedly connected to the outer side wall of the inner stator core unit 4-1 and the inner side wall of the outer stator core unit 6-1, respectively.

[0034] The outer stator core unit 6-1 is in a circular shape, and a plurality of slots are opened axially on the outer circumferential surface. The openings of the plurality of slots of the outer stator core unit 6-1 point to the outer rotor 7 and the center lines of the slot openings are evenly distributed along the circumference. An outer stator winding 6-2 is embedded in each slot to form an m-phase winding. When an m-phase symmetrical alternating current is passed, a rotating magnetic field with 2p poles is formed, where m and p are both positive integers.

[0035] The inner stator core unit 4-1 is annular, and its inner surface is also provided with a plurality of slots along the axial direction. The opening center lines of the plurality of slots on the inner stator core unit 4-1 are evenly distributed around the circumference of the output shaft 1-1, and an inner stator winding 4-2 is embedded in each slot to form m 1 Phase winding, pass m 1 When the alternating current is symmetrical, a 2p 1 Rotating magnetic field with number of poles, m 1 、p 1 All are positive integers.

[0036] See also Figure 2, the outer stator core unit 6-1, the outer stator permanent magnet 6-3, and the outer stator winding 6-2 constitute the outer stator 6, the inner stator core unit 4-1 and the inner stator winding 4-2 constitute the inner stator 4, and the inner rotor core unit 2-1 and the inner rotor permanent magnet 2-2 constitute the inner rotor 2. The outer stator 6 and the outer rotor 7 constitute a stator partitioned permanent magnet outer motor. The inner stator 4, the modulation rotor 3, and the inner rotor 2 constitute a permanent magnet magnetic field modulation inner motor, and satisfy p 1 =|hn+kq|, where h is a positive odd number and k is a positive integer. The inner stator 4, the stator magnetic shield 5 and the outer stator 6 constitute a stator unit 8.

[0037] The inner rotor core unit 2-1 is in the shape of a circular ring, and the inner rotor permanent magnet 2-2 is composed of 2n radially alternately magnetized permanent magnet units uniformly distributed along the circumference. The 2n permanent magnet units are embedded in the inner rotor core unit 2-1 or fixed on its outer circular surface. When the inner rotor 2 (inner rotor core unit 2-1, inner rotor permanent magnet 2-2) rotates, an inner rotor surface magnetic field with 2n poles is formed, where n is a positive integer.

[0038] The modulation rotor 3 is annular and is composed of q magnetic conductive blocks 3-1 and q insulating blocks 3-2 arranged alternately along the circumference, where q is a positive integer. The magnetic conductive blocks 3-1 are made of soft magnetic composite materials, silicon steel sheets, solid iron or soft magnetic ferrite.

[0039] The outer rotor 7 adopts a salient pole structure, and its radial inner rotating poles are evenly distributed on the circumference, and the structure is simple.

[0040] See also Figure 3 The inner rotor permanent magnet 2-2 adopts a surface-mounted Halbach permanent magnet structure, and the outer stator permanent magnet 6-3 uses a radial alternating magnetization method to increase the air gap magnetic density, compensate for the magnetic loss of the multi-air gap structure, reduce leakage magnetic field, and improve the power factor.

[0041] like Figure 4 As shown, the inner rotor 2 is fixedly connected to the output shaft 1-1. The modulation rotor 3 is fixedly connected to the input shaft 1-2 through the modulation rotor bracket 9, and is rotatably connected to the output shaft 1-1 through the first bearing 10 and the second bearing 11. The stator unit 8 is fixedly connected to the housing 13 through the stator bracket 12, and is rotatably connected to the output shaft 1-1 through the third bearing 14. The outer rotor 7 is fixedly connected to the output shaft 1-1 through the outer rotor bracket 15, and is rotatably connected to the housing through the fourth bearing 16. The motor housing 13 is rotatably connected to the input shaft 1-2 and the output shaft 1-1 through the fifth bearing 17 and the sixth bearing 18, respectively.

[0042] like Figure 5As shown, the hybrid system is driven by the brushless dual-rotor motor 19 proposed in the present invention. The dual-rotor motor 19 can be regarded as composed of a stator permanent magnet partition outer motor and a permanent magnet magnetic field modulation inner motor arranged concentrically. The outer stator 6 and the inner stator 4 both have armature windings. For detailed structures, see the above description. The modulation rotor 3 is connected to the output shaft of the engine 20 and can be regarded as the input rotor (input shaft 1-2) of the dual-rotor motor. The inner rotor 2 and the outer rotor 7 are both connected to the vehicle transmission shaft and can be regarded as the output rotor (output shaft 1-1) of the dual-rotor motor. The input rotor and the output rotor become the two mechanical ports of the motor. The armature windings (inner stator winding 4-2, outer stator winding 6-2) on the inner and outer stators (4, 6) are connected to the energy storage device 22 through the power conversion module 21, becoming two bidirectional electrical ports of the motor.

[0043] Applied in a hybrid power system, the present invention has the characteristics of brushless, high reliability, wide speed regulation range, and large torque output capability.

[0044] Applied to the series-parallel hybrid power system, the dual-rotor motor replaces the clutch, gearbox, starter, generator and planetary gear, etc. It has the advantages of the series mode, that is, the engine can operate independently in the high-efficiency line; it can also overcome the limitations of the series mode, that is, the engine output energy only provides a part of the electromagnetic power through mechanical energy-electrical energy-mechanical energy output, and most of it is directly transmitted to the output shaft by electromagnetic force, which greatly improves the efficiency and greatly reduces the capacity of the motor and battery.

[0045] When applied to hybrid power systems, it can realize the conversion of multiple working modes during hybrid drive and make the engine work in the optimal working area under any load (the internal motor provides the speed difference and the external motor provides the torque difference).

[0046] 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 brushless dual-rotor motor structure for a vehicle, characterized in that: The invention comprises an input rotating shaft (1-2), an output rotating shaft (1-1) coaxially arranged with the input rotating shaft (1-2), an inner rotor core unit (2-1) surrounding the output rotating shaft (1-1), an inner rotor permanent magnet (2-2) surrounding the inner rotor core unit (2-1), a modulation rotor (3) surrounding the inner rotor permanent magnet (2-2), an inner stator core unit (4-1) surrounding the modulation rotor (3), a stator magnetic shield (5) surrounding the inner stator core unit (4-1), an outer stator core unit (6-1) surrounding the stator magnetic shield (5), an outer stator permanent magnet (6-3) surrounding the outer stator core unit (6-1), and an outer rotor (7) surrounding the outer stator permanent magnet (6-3); Air gaps are provided between the inner rotor permanent magnet (2-2) and the modulation rotor (3), between the modulation rotor (3) and the inner stator core unit (4-1), between the outer stator core unit (6-1) and the outer stator permanent magnet (6-3), and between the outer stator permanent magnet (6-3) and the outer rotor (7); the inner rotor permanent magnet (2-2) is composed of 2n radially alternately magnetized permanent magnet units uniformly distributed along the circumference, where n is a positive integer; The inner rotor core unit (2-1) is fixed on the output shaft (1-1), the inner rotor permanent magnet (2-2) is fixed on the inner rotor core unit (2-1), and the radial inner and outer side walls of the stator magnetic shield (5) are respectively fixedly connected to the outer side wall of the inner stator core unit (4-1) and the inner side wall of the outer stator core unit (6-1); The modulation rotor (3) is fixedly connected to the input rotating shaft (1-2) via a modulation rotor bracket (9), and is rotationally connected to the output rotating shaft (1-1); the inner stator core unit (4-1), the stator magnetic shield (5), the outer stator core unit (6-1), and the outer stator permanent magnet (6-3) form a stator unit (8), which is fixedly connected to a motor housing (13) via a stator bracket (12), and is rotationally connected to the output rotating shaft (1-1); the outer rotor (7) is fixedly connected to the output rotating shaft (1-1) via an outer rotor bracket (15), and is rotationally connected to the motor housing (13); the motor housing (13) is rotationally connected to the input rotating shaft (1-2) and the output rotating shaft (1-1), respectively; The outer stator core unit (6-1) is in the form of a ring, and has a plurality of slots formed on its outer surface along the axial direction. The openings of the plurality of slots point toward the outer rotor (7) and the center lines of the slot openings are evenly distributed along the circumference. The plurality of slots are respectively embedded with outer stator windings (6-2) to form an m-phase winding. When an m-phase symmetrical alternating current is introduced, a rotating magnetic field with a pole number of 2p is formed, and m and p are both positive integers.

2. The brushless dual-rotor motor structure for a vehicle according to claim 1, characterized in that: The inner stator core unit (4-1) is in the shape of a ring, and has a plurality of slots on its inner surface along the axial direction, the opening center lines of the plurality of slots being evenly distributed in the circumferential direction around the output shaft (1-1), the plurality of slots respectively embedding the inner stator winding (4-2) to form an m1 phase winding, and when an m1 phase symmetrical alternating current is introduced, a rotating magnetic field with a pole number of 2p1 is formed, and m1 and p1 are both positive integers.

3. The brushless dual-rotor motor structure for a vehicle according to claim 2, characterized in that: The inner rotor core unit (2-1) is in the shape of a ring; the inner rotor permanent magnet (2-2) is embedded in the inner rotor core unit (2-1) or fixed on its outer circular surface; the inner rotor core unit (2-1) and the inner rotor permanent magnet (2-2) form an inner rotor (2); when the inner rotor (2) rotates, an inner rotor surface magnetic field with a pole number of 2n is formed.

4. The brushless dual-rotor motor structure for a vehicle according to claim 3, characterized in that: The modulation rotor (3) is in the shape of a ring and is composed of q magnetic conductive blocks (3-1) and q insulating blocks (3-2) which are staggered along the circumference, wherein q is a positive integer.

5. The brushless dual-rotor motor structure for a vehicle according to claim 4, characterized in that: The n, q, and p1 satisfy p1=|hn+kq|, wherein h is a positive odd number and k is a positive integer.

6. The vehicle brushless dual-rotor motor structure according to any one of claims 1 to 5, characterized in that: The outer rotor (7) adopts a salient pole structure, and its radially inner rotating poles are evenly distributed on the circumference.

7. The vehicle brushless dual-rotor motor structure according to any one of claims 1 to 5, characterized in that: The inner rotor permanent magnet (2-2) adopts a surface-mounted Halbach permanent magnet structure, and the outer stator permanent magnet (6-3) adopts a radial alternating magnetization method.

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