A dual-stator magnetic field modulation permanent magnet motor with tangential excitation at the stator slot opening

Abstract

A dual-stator field modulation permanent magnet motor with tangential excitation at the stator slot opening, comprising a rotor. An outer stator and an inner stator are respectively arranged on the inner side and the outer side of the rotor. The centers of the rotor, the outer stator and the inner stator are all set at the same point. The rotor is rotationally connected to the outer stator and the inner stator. Armature windings are arranged on both the inner side and the outer side of the rotor. At least one slot opening tangential excitation permanent magnet unit is arranged on the outer side of the inner stator and the inner side of the outer stator. The slot opening tangential excitation permanent magnet unit corresponds to the armature winding. The present invention combines two single-stator field modulation permanent magnet motors into one. Its permanent magnets and armature windings can be respectively placed on the stator side and the rotor side. At the same time, the inner stator and the outer stator are staggered by a certain angle to reduce magnetic leakage and increase torque. Meanwhile, two sets of armature windings are formed by using the outer stator, the inner stator and the rotor, effectively improving the magnetic field utilization rate and the torque density of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet magnetic field modulation motors, and in particular to a double-stator magnetic field modulation permanent magnet motor with tangential excitation at the stator slot opening. Background Art

[0002] Direct-drive permanent magnet motors have the advantages of high efficiency, high reliability, and low noise, and have broad application prospects in the industrial field. Compared with traditional direct-drive permanent magnet motors, magnetic field modulation permanent magnet motors have the advantages of high torque density and simple structure, and are suitable for industrial fields such as transportation that have higher requirements for torque density.

[0003] Since the permanent magnets and armature windings of traditional permanent magnet synchronous motors are respectively placed on the stator side or the rotor side, when a double-stator structure is adopted, the permanent magnets are generally placed on the middle rotor. For example, a new energy vehicle double-stator permanent magnet synchronous motor disclosed in the invention patent with the application number 202221992162.4 includes an outer stator silicon steel sheet, outer stator slots, outer stator windings, outer stator teeth, V-shaped magnetic isolation slots, linear magnets, inner stator teeth, inner stator slots, inner stator windings, outer air gaps, inner air gaps, and an inner stator body. The outer stator windings are arranged in the outer stator slots, the inner stator windings are arranged in the inner stator slots, and the linear permanent magnets are placed on the middle rotor. The motor has high working flexibility, but in high-speed motion scenarios, the structural reliability of this structure is poor, and there is a risk of permanent magnet detachment.

[0004] Moreover, double-stator magnetic field modulation motors with slotted stators often adopt an aligned double-stator structure. For example, a new type of hybrid-excitation double-stator doubly salient permanent magnet motor disclosed in the invention with the application number 202210833878.8 has armature windings and excitation windings respectively wound on the outer stator and inner stator teeth, the rotor is arranged between the outer stator and the inner stator, and the permanent magnets are placed on the inner stator yoke. Although this motor solves the shortcoming of the narrow speed regulation range of traditional permanent magnet motors. However, at this time, the magnetic resistance of the magnetic circuit of the motor is relatively large, resulting in relatively high magnetic leakage, which is not conducive to torque generation. Summary of the Invention

[0005] Aiming at the technical problems of high magnetic leakage and unreasonable structure existing in existing motors, the present invention proposes a double-stator magnetic field modulation permanent magnet motor with tangential excitation at the stator slot opening that can improve torque density. The center lines of the inner and outer stator teeth are staggered by a certain space electrical angle to form a staggered double-stator structure, which can reduce the magnetic leakage of the motor.

[0006] To achieve the above object, the technical solution of the present invention is implemented as follows: A double-stator magnetic field modulation permanent magnet motor with tangential excitation at the stator slot opening, comprising a rotor, an outer stator and an inner stator are respectively arranged on the inner side and the outer side of the rotor, the centers of the rotor, the outer stator and the inner stator are all set at the same point, the rotor is rotatably connected to the outer stator and the inner stator, armature windings are arranged on both the inner side and the outer side of the rotor, at least one slot-opening tangential excitation permanent magnet unit is arranged on the outer side of the inner stator and the inner side of the outer stator, and the slot-opening tangential excitation permanent magnet unit corresponds to the armature winding.

[0007] The slot-opening tangential excitation permanent magnet unit includes p os pole outer stator permanent magnets and p is pole inner stator permanent magnets, the p os pole outer stator permanent magnets are arranged on the inner side of the outer stator, and the p is pole inner stator permanent magnets are arranged on the outer side of the inner stator.

[0008] The inner stator and the outer stator are of an interleaved double-stator structure, and the included angle between the inner stator and the outer stator is 7.5 electrical degrees.

[0009] Inner stator teeth are uniformly arranged on the inner stator, p is pole inner stator permanent magnets are arranged between adjacent inner stator teeth, outer stator teeth are uniformly arranged on the outer stator, p os pole outer stator permanent magnets are arranged between adjacent outer stator teeth, and the width of the inner stator teeth is less than the width of the outer stator teeth.

[0010] The outer stator is a circular outer stator, the inner stator is a circular inner stator, the rotor is a circular rotor, the circular outer stator, the circular rotor and the circular inner stator are coaxially sleeved from outside to inside in sequence, and gaps are arranged between the circular outer stator, the circular rotor and the circular inner stator.

[0011] At least one rotor tooth is uniformly arranged on the circular rotor, the length of the rotor tooth is greater than the width of the circular rotor, the midpoint of the rotor tooth is fixedly connected to the circular rotor, an outer ring slot is arranged between adjacent rotor teeth on the outer side of the circular rotor, an inner ring slot is arranged between adjacent rotor teeth on the inner side of the circular rotor, and the armature winding passes through the outer ring slot or the inner ring slot and is arranged on the rotor teeth at intervals.

[0012] The rotor tooth is a trapezoidal rotor tooth, and the width of the trapezoidal rotor tooth gradually increases from the inner side to the outer side of the circular rotor.

[0013] The armature winding includes a first set of armature windings and a second set of armature windings. The first set of armature windings passes through the outer ring slot and is arranged on the trapezoidal rotor teeth at intervals, the second set of armature windings passes through the inner ring slot and is arranged on the trapezoidal rotor teeth at intervals, and the first set of armature windings and the second set of armature windings are correspondingly arranged on the rotor teeth.

[0014] The number of the rotor teeth is an integer multiple of the number of phases of the permanent magnet motor:

[0015] Z r = nm, n = 1, 2, 3…,

[0016] Z r is the number of rotor teeth, m is the number of phases of the motor, n = 1, 2, 3…

[0017] The relationship among the number of pole pairs of the motor armature winding, the number of pole pairs of the stator slot tangential field-excited permanent magnet unit, and the number of rotor teeth satisfies the following formula:

[0018] p a = |Z r - p os |;

[0019] p a = |Z r - p is |;

[0020] G r = - p a / p s ;

[0021] where Z r is the number of rotor teeth, p a is the number of pole pairs of the motor armature winding, p s is the number of pole pairs of the stator slot tangential field-excited permanent magnet unit, G r is the transmission ratio, f is the frequency of the stator current, n is the motor speed, n = 60f / p a .

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The present invention uses an outer stator, an inner stator and a rotor to form two sets of armature windings, which effectively improves the magnetic field utilization rate and increases the torque density of the motor. The present invention uses an outer stator, an inner stator and a rotor to form two sets of armature windings, which effectively improves the magnetic field utilization rate,

[0024] increases the torque density of the motor, thereby meeting the industrial applications with high torque density requirements. The motor design of the present invention has the advantages of compact structure, stable operation and convenient maintenance.

[0025] 2. The present invention includes a double-stator motor structure with an outer stator, an inner stator and a rotor, which has two layers of air gaps, can effectively improve the permanent magnet magnetic circuit of the motor, can make full use of the internal space of the rotor and increase the torque density and power density of the motor.

[0026] 3. Both sets of armature windings of the motor of the present invention adopt the form of concentrated windings, which can effectively reduce the length of the winding end, reduce the copper loss, and thus improve the operating efficiency of the motor.

[0027] 4. The present invention adopts an interleaved double-stator structure, which offsets the inner stator and the outer stator by a certain spatial electrical angle in the circumferential direction, effectively reducing the magnetic leakage of the motor.

[0028] 5. The double-stator field modulation permanent magnet motor with tangential excitation of the stator slot opening of the present invention has the characteristic of high torque output and is an ideal choice for direct drive applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a schematic structural diagram of the motor in the embodiment of the present invention.

[0031] Figure 2 It is a schematic structural diagram of the inner stator field modulation motor and the outer stator field modulation motor.

[0032] Figure 3 It is a comparison diagram of the load torque waveforms of the motor in the embodiment of the present invention.

[0033] Figure 4 It is a back electromotive force waveform diagram of the motor in the embodiment of the present invention when it is no-load.

[0034] In the figure, 1 is the rotor, 10 is the rotor tooth, 11 is the rotor armature winding, 110 is the first set of armature windings, 111 is the second set of armature windings, 2 is the outer stator, 3 is the inner stator, and 4 is the tangential excitation permanent magnet unit at the slot opening. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] Embodiment 1

[0037] As Figure 1As shown, a dual-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation includes a rotor 1, an outer stator 2 and an inner stator 3 are arranged on both sides of the rotor 1, the centers of the rotor 1, the outer stator 2 and the inner stator 3 are all arranged at the same point, the rotor 1 is rotatably connected with the outer stator 2 and the inner stator 3, the inner and outer sides of the rotor 1 are arranged with an armature winding 11, the outer side of the inner stator 3 and the inner side of the outer stator 2 are each provided with at least one slot tangential excitation permanent magnet unit 4, and the slot tangential excitation permanent magnet unit 4 corresponds to the armature winding 11.

[0038] The inner stator 3 and the outer stator 2 are staggered double stator structures, staggered by a certain spatial electrical angle in the circumferential direction. The angle between the inner stator 3 and the outer stator 2 is 7.5 electrical degrees, which effectively reduces the leakage magnetic field of the motor.

[0039] The slot tangential excitation permanent magnet unit 4 includes p os The stator permanent magnets are located outside the pole and p is Pole pair inner stator permanent magnet, p os The outer stator permanent magnet is arranged on the inner side of the outer stator 2. is The inner stator permanent magnets of the pole pair are arranged outside the inner stator 3. By setting p os The stator permanent magnets are located outside the pole and p is The stator permanent magnets inside the pole pair effectively utilize the internal space of the motor to make the motor more efficient and compact. The bidirectional magnetic field modulation effect generated by the two parts of the permanent magnets can effectively increase the harmonic content of the air gap magnetic field to achieve higher torque density. The slot tangential excitation permanent magnet unit 4 is made of neodymium iron boron rare earth permanent magnet material.

[0040] The present invention utilizes an outer stator, an inner stator and a rotor to form an inner and outer double-stator motor structure with two layers of air gaps, which can effectively improve the permanent magnet magnetic circuit of the motor, fully utilize the internal space of the rotor and improve the torque density and power density of the motor.

[0041] The inner stator 3 is evenly provided with inner stator teeth, and p is provided between adjacent inner stator teeth. is The inner stator permanent magnet has a pole pair, and the outer stator 2 is evenly provided with outer stator teeth, and p is provided between adjacent outer stator teeth. os The pole is toward the outer stator permanent magnet, and the width of the inner stator tooth is smaller than the width of the outer stator tooth.

[0042] Specifically, the outer stator 2 is a circular outer stator, the inner stator 3 is a circular inner stator, and the rotor 1 is a circular rotor. The circular outer stator, circular rotor, and circular inner stator are coaxially sleeved from outside to inside in sequence, and there is a gap between the circular outer stator, circular rotor, and circular inner stator. At least one rotor tooth 10 is evenly arranged on the circular rotor. The length of the rotor tooth 10 is greater than the width of the circular rotor. The midpoint of the rotor tooth 10 is fixedly connected to the circular rotor, and both ends of the rotor tooth 10 protrude from the inner and outer sides of the circular rotor. An outer ring groove is arranged between adjacent rotor teeth 10 on the outer side of the circular rotor, and an inner ring groove is arranged between adjacent rotor teeth 10 on the inner side of the circular rotor. The armature winding 11 passes through the outer ring groove or the inner ring groove and is arranged on the rotor tooth 10 at intervals. That is, if the armature winding 11 is wound on a rotor tooth 10, there is no armature winding 11 on the rotor teeth 10 adjacent to this rotor tooth 10. The winding method of the armature winding 11 is as Figure 1 shown. The "+" is the current inlet direction of the rotor winding, the "-" is the current outlet direction of the stator winding, and A, B, and C are the three-phase windings of the motor. The armature winding 11 is a concentrated winding, which is beneficial to reducing the end length and lowering the copper loss.

[0043] The armature winding 11 includes a first set of armature windings 110 and a second set of armature windings 111. The first set of armature windings 110 is arranged in the outer ring groove, and the second set of armature windings 111 is arranged in the inner ring groove. The first set of armature windings 110 and the second set of armature windings 111 are correspondingly arranged on the rotor tooth 10. That is, when a first set of armature windings 110 is arranged on one end of the rotor tooth 10 protruding from the outer side of the circular rotor, a corresponding second set of armature windings 111 is arranged on the end of this rotor tooth 10 protruding from the inner side of the circular rotor. As Figure 2 shown, the first set of armature windings 110 and the second set of armature windings 111 operate independently. The inner stator 3, the rotor 1, and the second set of armature windings 111 arranged on the inner side of the rotor form an inner stator field modulation motor, and the outer stator 2, the rotor 1, and the first set of armature windings 110 arranged on the outer side of the rotor form an outer stator field modulation motor.

[0044] Both sets of armature windings of the motor in the present invention adopt the concentrated winding form, which can effectively reduce the winding end length, lower the copper loss, reduce the cost, and improve the motor operation efficiency at the same time.

[0045] The number of rotor teeth 10 is an integer multiple of the number of phases of the permanent magnet motor, and the expression is:

[0046] Z r = nm, n = 1, 2, 3…,

[0047] Z r is the number of rotor teeth 10, m is the number of phases of the motor, and n = 1, 2, 3…

[0048] The relationship among the number of pole pairs of the motor armature winding, the number of pole pairs of the stator slot tangential field-excited permanent magnet unit, and the number of rotor teeth satisfies the following formula:

[0049] p a =|Z r -p os |;

[0050] p a =|Z r -p is |;

[0051] G r =-p a / p s ;

[0052] Wherein, Z r is the number of rotor teeth, p a is the number of pole pairs of the motor armature winding, p s is the number of pole pairs of the stator slot tangential field-excited permanent magnet unit, G r is the transmission ratio, f is the stator current frequency, n is the motor speed, and n = 60f / p a .

[0053] Embodiment 2

[0054] A double-stator field-modulated permanent magnet motor with tangential field excitation in the stator slots. Referring to Figure 1 , the double-stator field-modulated permanent magnet motor of the embodiment of the present invention is composed of an outer stator 2, a rotor 1, and an inner stator 3. The outermost is the outer stator 2, which is coaxially and clearance-fitted outside the rotor 1, and the rotor 1 is coaxially and clearance-fitted outside the inner stator 3. In summary, in the radial direction of the present invention, the inner stator 3, the rotor 1, and the outer stator 2 are coaxially sleeved in sequence from the inside to the outside. The outer stator 2 is composed of an outer stator yoke and a stator slot tangential field-excited permanent magnet unit. The stator slot tangential field-excited permanent magnet unit 4 is placed at the stator slot opening along the inner circle of the outer stator yoke. The outer side of the inner stator 3 is evenly provided with slots, and the stator slot tangential field-excited permanent magnet unit 4 is arranged in the slots. The stator slot tangential field-excited permanent magnet unit 4 is magnetized tangentially, and the magnetization directions of adjacent permanent magnets in the same stator slot are opposite.

[0055] In this embodiment, in the radial direction, there is an inner air gap of 0.5 mm between the outer surface of the outer circle of the motor inner stator 3 and the inner surface of the rotor 1, and an outer air gap of 0.5 mm between the inner surface of the outer stator 2 and the outer surface of the rotor 1. The rotor 1, the outer stator 2, and the outer stator 3 are all laminated from high-permeability DW540 silicon steel sheets.

[0056] The rotor 1 is in a circular ring shape and includes an armature winding 11 and rotor teeth 10. The rotor armature winding 11 is placed in the rotor slots and is wound around the rotor teeth 10 in a concentrated manner. The area of the tangentially excited permanent magnet unit at the slot opening of the dual-stator magnetic field modulation motor is 684.2 mm 2 . There are 24 rotor teeth on both the upper and lower parts of the motor rotor, which serve as modulation teeth to modulate the tangentially excited permanent magnet units at the slot openings of the inner and outer stators. The center lines of the 3 teeth of the inner stator and the 2 teeth of the outer stator of the motor are staggered by 7.5 electrical angular degrees. At this time, the leakage magnetic flux is the smallest, satisfying γ = 360° / 2Z r , where γ is the angular difference between the center lines of the 3 teeth of the inner stator and the 2 teeth of the outer stator.

[0057] Figure 1 The winding diagram of the motor according to the present invention is given. The rotor winding is a three-phase armature winding, and the three-phase armature winding is concentrated and wound around the rotor teeth. Adopting the form of concentrated winding can effectively reduce the length of the winding end, reduce the copper loss, and thus improve the operating efficiency of the motor. The "+" is the current inlet direction of the rotor winding, the "-" is the current outlet direction of the stator winding, and A, B, and C are the three-phase windings of the motor.

[0058] See Figures 3 - 4 , Figure 3 , which is the torque waveform diagram of the motor according to the present invention under load. It can be seen from the figure that the output torque when the dual-stator permanent magnet is excited is greater than the sum of the output torques when two single-stator permanent magnets are excited. Figure 4 is the back electromotive force waveform diagram of the motor under no-load. As shown in the figure, the motor according to the present invention can be regarded as the combination of two motors. Therefore, the back electromotive force is the sum generated by the two motors.

[0059] The invention combines two single-stator magnetic field modulation permanent magnet motors into one. Its permanent magnets and armature windings can be respectively placed on the stator side and the rotor side. At the same time, the inner and outer stators are staggered by a certain angle to reduce the leakage magnetic flux and increase the torque. At the same time, two sets of armature windings are formed by using the outer stator, inner stator, and rotor, effectively improving the magnetic field utilization rate and increasing the torque density of the motor.

[0060] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A double-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation, characterized in that: The invention comprises a rotor (1), wherein an inner stator (3) and an outer stator (2) are respectively arranged on the inner side and the outer side of the rotor (1), wherein the centers of the rotor (1), the outer stator (2) and the inner stator (3) are all arranged at the same point, wherein the rotor (1) is rotatably connected to the outer stator (2) and the inner stator (3), wherein an armature winding (11) is arranged on the inner side and the outer side of the rotor (1), wherein at least one slot tangential excitation permanent magnet unit (4) is arranged on the outer side of the inner stator (3) and the inner side of the outer stator (2), wherein the slot tangential excitation permanent magnet unit (4) corresponds to the armature winding (11); The slot tangential excitation permanent magnet unit (4) comprises p os The stator permanent magnets are located outside the pole and p is Pole pair inner stator permanent magnet, p os The stator permanent magnet with the pole facing outward is arranged on the inner side of the outer stator (2), is The inner stator permanent magnets of the pole pair are arranged outside the inner stator (3); The outer stator (2) is a circular outer stator, the inner stator (3) is a circular inner stator, and the rotor (1) is a circular rotor. The circular outer stator, the circular rotor, and the circular inner stator are coaxially mounted in sequence from the outside to the inside, and a gap is provided between the circular outer stator, the circular rotor, and the circular inner stator. At least one rotor tooth (10) is evenly arranged on the circular rotor, the length of the rotor tooth (10) is greater than the width of the circular rotor, the midpoint of the rotor tooth (10) is fixedly connected to the circular rotor, an outer ring groove is arranged between adjacent rotor teeth (10) on the outer side of the circular rotor, and an inner ring groove is arranged between adjacent rotor teeth (10) on the inner side of the circular rotor, and the armature winding (11) passes through the outer ring groove or the inner ring groove and is arranged on the rotor teeth (10) at intervals.

2. The double-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation according to claim 1, characterized in that: The inner stator (3) is evenly provided with inner stator teeth, and p is provided between adjacent inner stator teeth. is Pole pairs inner stator permanent magnets, The outer stator (2) is evenly provided with outer stator teeth, and p is provided between adjacent outer stator teeth. os The pole is toward the outer stator permanent magnet, and the width of the inner stator tooth is smaller than the width of the outer stator tooth.

3. The double-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation according to claim 2, characterized in that: The inner stator (3) and the outer stator (2) are of an interlaced double stator structure, and the included angle between the inner stator (3) and the outer stator (2) is 7.5 electrical degrees.

4. The double-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation according to claim 3, characterized in that: The rotor teeth (10) are trapezoidal rotor teeth, and the width of the trapezoidal rotor teeth gradually increases from the inner side of the circular rotor to the outer side of the circular rotor.

5. The double-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation according to claim 4, characterized in that: The armature winding (11) comprises a first set of armature windings (110) and a second set of armature windings (111); the first set of armature windings (110) is arranged on the trapezoidal rotor teeth through the outer ring slots, and the second set of armature windings (111) is arranged on the trapezoidal rotor teeth through the inner ring slots. The first set of armature windings (110) and the second set of armature windings (111) are arranged on the rotor teeth (10) correspondingly.

6. A design method for a dual-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation according to any one of claims 1 to 5, characterized in that: The number of the rotor teeth (10) is an integer multiple of the number of phases of the permanent magnet motor: Z r =nm,n=1,2,3…, Among them, Z r is the number of rotor teeth (10), and m is the number of motor phases.

7. The design method of the dual-stator magnetic field modulation permanent magnet motor with stator slot tangential excitation according to claim 6 is characterized in that: The relationship between the number of armature winding pole pairs, the number of stator slot tangential excitation permanent magnet unit pole pairs and the number of rotor teeth satisfies the following formula: p a =|Z r -p os |; p a =|Z r -p is |; G r =-p a / p s ; Among them, Z r is the number of rotor teeth (10), p a is the number of pole pairs of the motor armature winding, p s is the number of pole pairs of the stator slot tangential excitation permanent magnet unit (4), G r is the transmission ratio, f is the stator current frequency, n is the motor speed, n = 60f / p a .

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