Load migration type strong overload double-stator vernier permanent magnet motor

Abstract

The invention discloses a load migration type strong overload double-stator vernier permanent magnet motor, and belongs to the field of permanent magnet motors. The motor comprises an inner stator, an outer stator and a rotor which are coaxially sleeved; a permanent magnet and a ferromagnetic pole array which are magnetized tangentially and radially are embedded in the rotor, so that relatively large primary magnetomotive force and relatively large tertiary magnetomotive force can be generated in an inner air gap and an outer air gap respectively; the outer stator utilizes three times of magnetomotive force, so that armature reaction can be reduced, and saturation is not easy in a high-load range; the inner stator utilizes primary magnetomotive force and adopts a directional design structure, so that the counter electromotive force of the inner stator is larger than that of the outer stator under low load, and as the load is increased, the counter electromotive force of the inner stator is smaller than that of the outer stator due to the fact that primary armature harmonic of the inner stator of the motor is high in content and easy to saturate and the counter electromotive force of the inner stator is smaller than that of the outer stator, the load is transferred to the outer stator from the inner stator. The problem of motor saturation can be relieved, torque density maximization in a wide load range is achieved, and the overload capacity of the motor is improved.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet motors, and more specifically, relates to a load-transfer type strong overload dual-stator vernier permanent magnet motor. Background Technology

[0002] As a widely used and critical basic component, electric motors play a key role in improving the overall level of the equipment manufacturing industry. Among them, high torque density and overload capacity have always been the main goals of electric motor development, which are of great significance for reducing motor size and cost and improving response speed.

[0003] Conventional permanent magnet motors generally rely on a single working magnetic field to generate torque, and the improvement of torque density is limited by material properties and cooling methods. Vernier permanent magnet motors are structurally similar to conventional permanent magnet motors, but based on the principle of magnetic field modulation, they utilize two working magnetic fields to convert electromechanical energy into torque, thus achieving a higher torque density. Currently, the topology with the highest torque density is the dual-stator tangentially excited vernier permanent magnet motor. Theoretically, as the motor pole ratio increases, the torque density increases; however, motor saturation also increases, and overload performance deteriorates, thus preventing the full advantages of this motor from being realized. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a load-transfer type strong overload dual-stator vernier permanent magnet motor, which can alleviate the saturation of the motor under overload conditions and improve the overload capacity of the motor.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a load-transfer type high overload dual-stator vernier permanent magnet motor is provided, characterized in that it comprises: a rotating shaft, an inner stator, a rotor, and an outer stator coaxially arranged in a radial direction from the inside to the outside; An air gap is formed between the rotor and both the inner and outer stators; the rotor is embedded with arrays of permanent magnets distributed tangentially and radially; the winding frequency of the outer stator is three times that of the winding frequency of the inner stator. The air gap side of the outer stator adopts an open slot structure, and coils are wound on the outer stator teeth; the armature winding pole pairs of the outer stator are... Compared with the outer stator pole ratio Satisfying the relation , and the number of teeth of the outer stator Satisfying the relation ; This represents the number of rotor pole pairs; The inner stator includes a stator yoke, a first auxiliary tooth, a main tooth, and an auxiliary tooth structure; wherein the first auxiliary tooth and the main tooth are symmetrically distributed circumferentially on the side of the stator yoke, and the included angle between any main tooth and any adjacent first auxiliary tooth is 0.5°. The auxiliary tooth structure is an axisymmetric structure disposed on the main tooth, including one second auxiliary tooth and two third auxiliary teeth, and the number of the main tooth and the first and second auxiliary teeth is [missing information]. The number of third auxiliary teeth is , The value is a positive integer greater than or equal to 1; a coil is wound on the main tooth; the number of pole pairs of the armature winding of the inner stator is... Compared with the inner stator pole ratio Satisfying the relation The number of main teeth of the inner stator Satisfying the relation The width of the first to third auxiliary teeth and the groove depth and width of the tooth slots in the auxiliary tooth structure were obtained through simulation optimization with the goal of maximizing the no-load fundamental back EMF of the motor.

[0006] According to a second aspect of the present invention, a control method for a load-transfer type high-overload dual-stator vernier permanent magnet motor as described in the first aspect is provided, comprising: When the motor load is below the load threshold, adjust the current intensity of the inner and outer stator armature windings respectively to concentrate the motor load on the inner stator; when the motor load is greater than or equal to the load threshold, adjust the current intensity of the inner and outer stator armature windings respectively to concentrate the motor load on the outer stator.

[0007] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: The load-transfer type high overload dual-stator vernier permanent magnet motor provided by this invention includes an inner stator, an outer stator, and a rotor coaxially mounted. The rotor structure is embedded with radially and tangentially magnetized permanent magnets. Air gaps are formed between the rotor and both the inner and outer stators. The winding frequency of the outer stator is three times that of the inner stator, generating a larger first-order magnetomotive force in the inner air gap and a larger third-order magnetomotive force in the outer air gap. This generates a multi-time-domain working magnetic field, resulting in more and larger amplitude working magnetic fields compared to traditional vernier permanent magnet motors, thus providing stronger torque generation capability. The outer stator utilizes higher-order armature magnetomotive forces, reducing armature reaction and enabling operation over high load ranges. The inner stator is less prone to saturation and has a high torque density under overload conditions. The inner stator adopts an directional design: the width of the first to third auxiliary teeth on the air gap side and the groove depth and width of the tooth slots in the auxiliary tooth structure are optimized using finite element simulation software with the goal of maximizing the no-load fundamental back EMF of the motor. This allows the back EMF of the inner stator to be greater than that of the outer stator under low load. As the load increases, due to the high content of the first armature harmonic in the inner stator, it is prone to saturation, and the back EMF of the inner stator will be less than that of the outer stator. By transferring the load from the inner stator to the outer stator, the saturation problem of the motor can be alleviated, the torque density can be maximized over a wide load range, and the overload capacity of the motor can be improved. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the outer stator structure of a load-transfer type high-overload dual-stator vernier permanent magnet motor provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the rotor structure of a load-transfer type high-overload dual-stator vernier permanent magnet motor provided in an embodiment of the present invention; Figure 3 A schematic diagram of the inner stator structure of a load-transferring, high-overload dual-stator vernier permanent magnet motor provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the overall structure of a load-transfer type high-overload dual-stator vernier permanent magnet motor provided in an embodiment of the present invention.

[0009] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Outer stator, 2-Outer stator winding, 3-Tangential permanent magnet array, 4-Radial permanent magnet array, 5-Rotor, 6-Inner stator, 7-Inner stator winding, 8-Shaft, 61-Stator yoke, 62-First auxiliary tooth, 63-Second auxiliary tooth, 64-Third auxiliary tooth, 65-Main tooth. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0011] The existing dual-stator tangentially excited vernier permanent magnet motor has a tangentially excited rotor structure that generates a fundamental magnetomotive force and higher-order magnetomotive forces such as 3, 5, and 7 in both the inner and outer air gaps (the higher the order of the magnetomotive force, the smaller its value). However, the content of higher-order magnetomotive forces in the inner and outer air gaps of this rotor structure is relatively small.

[0012] Based on this, the present invention provides a load-transfer type strong overload dual-stator vernier permanent magnet motor, comprising: a rotating shaft 8, an inner stator 6, a rotor 5 and an outer stator 1 coaxially arranged in the radial direction from the inside to the outside; An air gap is formed between the rotor 5 and both the inner stator 6 and the outer stator 1; the rotor 5 is embedded with a permanent magnet array distributed tangentially and a permanent magnet array distributed radially, the permanent magnet array distributed tangentially is magnetized, and the permanent magnet array distributed radially is magnetized; the winding frequency of the outer stator 1 is three times that of the winding frequency of the inner stator 6. The air gap side of the outer stator 1 adopts an open slot structure, and coils are wound on the outer stator teeth; the armature winding pole pairs of the outer stator 1 are... Compared with the outer stator pole ratio Satisfying the relation , and the number of teeth of the outer stator Satisfying the relation ; This represents the number of rotor pole pairs; The inner stator 6 includes a stator yoke 61, a first auxiliary tooth 62, a main tooth 65, and an auxiliary tooth structure. The first auxiliary tooth 62 and the main tooth 65 are symmetrically distributed circumferentially on the side of the stator yoke, and the included angle between any main tooth 65 and any adjacent first auxiliary tooth 62 is the same. The auxiliary tooth structure is an axisymmetric structure disposed on the main tooth, including one second auxiliary tooth 63 and two third auxiliary teeth 64, that is, the two third auxiliary teeth 64 are symmetrical about the second auxiliary tooth 63. The first to third auxiliary teeth are all located on the air gap side, and the main tooth is located on the stator yoke side. A coil is wound on the main tooth 65. The number of armature winding pole pairs of the inner stator 1 is... Compared with the inner stator pole ratio Satisfying the relation The number of main teeth of the inner stator Satisfying the relation The width of the first to third auxiliary teeth and the groove depth and width of the tooth slots in the auxiliary tooth structure were obtained by simulation optimization design using finite element simulation software with the goal of maximizing the no-load fundamental back EMF of the motor.

[0013] Specifically, the load-transfer type high overload dual-stator vernier permanent magnet motor provided in this embodiment of the invention includes two stators and one rotor, which are arranged radially from the outside to the inside as follows: outer stator 1, rotor 5, inner stator 6, and shaft 8; as shown... Figure 1 As shown, the rotor 8 is embedded with a tangential permanent magnet array 3 and a radial permanent magnet array 4, and the rotor is made of ferromagnetic material; as Figure 2 As shown, the outer stator has an open slot structure, and the outer stator winding 2 is wound on the outer stator teeth; the inner stator has an oriented design structure, and the inner stator includes main teeth and auxiliary teeth, with the inner stator winding 7 wound on the main teeth. Both the inner and outer stators are made of ferromagnetic materials.

[0014] The load-transferring, high-overload dual-stator vernier permanent magnet motor provided in this embodiment of the invention employs a novel hybrid excitation rotor structure, which can increase the content of higher-order magnetomotive forces (MTFs) without reducing the fundamental MMF. The hybrid excitation rotor includes a tangential permanent magnet array and a radial permanent magnet array, generating a higher first-order MMF in the inner air gap and a higher third-order MMF in the outer air gap. To simultaneously utilize these MMF harmonics, the inner and outer stators and their winding structures are designed separately, with the outer stator winding frequency being three times the inner stator winding frequency.

[0015] To enhance the amplitude of the excitation magnetomotive force (EMF), the hybrid excitation rotor structure was optimized. Theoretically, a larger tertiary and primary MMF are better, but they are mutually restrictive. Under the premise that both the internal and external stator electrical loads are at their rated operating conditions, the design is based on the number of pole pairs in the armature winding of the external stator. and number of external stator teeth Using simulation software such as Maxwell and JMAG, the magnet dimensions (including the length and width of the radial and tangential permanent magnets) of the hybrid excitation rotor of the motor were optimized with the goal of maximizing the motor torque, and the inner and outer diameters of the rotor were finally obtained.

[0016] Considering that the higher the order of the magnetomotive force (MOF), the smaller its value, the external stator utilizes a third-order MOF. If the pole ratio remains constant, according to the principle of magnetic field modulation, the number of armature pole pairs increases, the armature reaction weakens, the motor saturation is reduced, and the overload capacity increases. However, the number of stator teeth increases, the modulation effect weakens, and the motor's no-load back EMF decreases. Therefore, reducing the motor's pole ratio and the number of motor teeth increases the modulation effect while simultaneously enhancing the motor's overload capacity. The number of rotor pole pairs in a dual-stator vernier permanent magnet motor is... The number of pole pairs of the third harmonic magnetomotive force is Number of teeth on the outer stator Number of armature winding pole pairs of the outer stator Compared with the outer stator pole ratio The following relationship must be satisfied:

[0017]

[0018] Based on the external stator pole ratio The above relationship is used to design the number of teeth on the external stator. Number of pole pairs of armature windings of the outer stator .

[0019] Rotor pole pairs and the pole ratio of the inner and outer stators , The design was optimized using simulation software based on the given outer stator diameter, with the goal of maximizing motor torque.

[0020] The rotor's magnet dimensions are based on the number of armature winding pole pairs of the outer stator. and number of external stator teeth The rotor was designed with the goal of maximizing motor torque density. The rotor's magnet dimensions include the length and width of permanent magnets distributed tangentially and radially. The number of radially and tangentially distributed permanent magnets is equal, both being twice the number of rotor pole pairs.

[0021] The inner diameter of the outer stator, the width of the outer stator teeth, the width of the slot opening, and the slot depth are optimized using simulation software based on the dimensions of the rotor's magnets, with the goal of maximizing the motor torque.

[0022] The rotor outer diameter is the difference between the outer stator inner diameter and twice the air gap length. The air gap length is determined based on the outer stator outer diameter and engineering experience. The rotor inner diameter is the difference between the rotor outer diameter and twice the length of the tangential permanent magnet.

[0023] Based on the number of teeth on the outer stator Number of pole pairs of armature windings of the outer stator Choose the winding method of the outer stator winding 2 (concentrated winding or distributed winding) so that the winding coefficient is greater than the winding coefficient threshold (usually 0.866).

[0024] The aforementioned external stator utilizes the polarity-changing effect to increase the number of armature pole pairs and reduce armature reaction, thus possessing the advantage of strong overload capacity.

[0025] The inner stator utilizes the fundamental magnetomotive force (MMF). Based on the fundamental MMF, the width of the first to third auxiliary teeth in the inner stator, as well as the groove depth and width of the tooth slots in the auxiliary tooth structure, are designed to achieve the theoretically strongest torque capacity. The design principle is as follows: (1) The motor is divided into multiple identical unit motors according to the number of poles and the number of internal stator slots. The number of unit motors is equal to the number of rotor pole pairs. and number of internal stator slots The greatest common divisor.

[0026] (2) Taking a concentrated winding as an example (the same principle can be used to analyze and derive a distributed winding), in a concentrated winding, the magnetic flux density is only at the center of the coil. The magnetic permeability element at a given point is not zero, and the resulting magnetic flux links with the coil. Combining the magnetic flux density amplitude at a single point with the magnetomotive force and magnetic permeability, the magnetic flux within a single coil in a concentrated winding structure within a unit motor can be obtained. Φ for:

[0027] in, The inner air gap radius is... For the length of the motor stack, This represents the amplitude of the fundamental magnetomotive force (i.e., the fundamental magnetomotive force). This refers to the motor speed. The phase of the excitation magnetomotive force is the fundamental wave phase. The winding span, Let be the permeability function. Integrating the magnetic flux and differentiating with respect to time yields the overall no-load fundamental back EMF of the motor. for

[0028] In the formula, The number of turns in series per phase. This is a characterization function for the amplitude of the fundamental back EMF of the unit motor under no-load conditions. It is about The function of , and is completely consistent with the characteristics of the fundamental magnetomotive force, only by and Decision. Simultaneously, the air gap permeability function The value of will affect The specific case of integration along the interval, that is, making Maximum, that is, to make and The product of these terms has the largest area over the integration range.

[0029] (3) In the inner stator structure provided by the present invention, the main teeth are located on the stator yoke side, and the first to third auxiliary teeth are all located on the air gap side. Therefore, the air gap permeability function The values ​​are determined by the widths of the first to third auxiliary teeth. , , The groove depth of the tooth groove in the auxiliary tooth structure , , , slot width The decision was made to use finite element simulation software to maximize the unloaded fundamental back EMF. To achieve the desired result, the above parameters were obtained through optimized design.

[0030] During optimization, a suitable winding span can be set first based on experience. Then, finite element simulation software is used to maximize the unloaded fundamental back EMF. To achieve the target, the auxiliary tooth parameters corresponding to the winding span are obtained through optimized design (i.e., , , , , , , ).

[0031] If the winding span is uncertain The optimal value can also be obtained through scanning. Multiple sets of auxiliary tooth parameters corresponding one-to-one with the span of multiple windings are obtained. The set of auxiliary tooth parameters that maximizes the inner stator torque is selected as the final auxiliary tooth parameters. Based on this, with the maximum torque as the objective, the inner stator inner diameter is optimized by combining the value of the outer diameter of the rotor shaft in engineering applications. The outer diameter of the inner stator is the difference between the inner diameter of the rotor and twice the air gap length.

[0032] The structural parameters of the main teeth are designed independently of the above process. The number of main teeth is the product of the number of unit motors and the number of current phases. The width and length of the main teeth are optimized by maximizing the inner stator torque. Furthermore, the gap between the main teeth and the adjacent first auxiliary teeth is defined as the main slot, which is... Figure 3 It can be seen that the width and length of the main tooth determine the slot width and slot depth of the main slot, respectively. The winding is placed in the main slot. Therefore, the slot depth and slot width of the main slot can be further optimized by combining the volume of the winding in engineering applications, that is, the width and length of the main tooth are optimized in reverse.

[0033] It is understandable that the width of the auxiliary tooth and the main tooth refer to the dimensions of the auxiliary tooth and the main tooth along the circumference of the stator, respectively.

[0034] The distribution of the inner stator winding 7 on the inner stator main teeth is selected based on the winding span corresponding to the set of auxiliary tooth parameters that maximize the inner stator torque.

[0035] Conventional magnetic field modulation permanent magnet motors typically use only two magnetic flux density harmonics, the fundamental term and the modulation term, to generate average torque. The motor provided by this invention is a multi-operating harmonic magnetic field modulation permanent magnet motor, which offers a new approach to torque enhancement. The inner stator structure designed in the above manner can increase the motor's no-load back EMF and improve torque density.

[0036] In summary, the motor provided by the embodiments of the present invention can solve the problems of easy overload saturation, low utilization rate of air gap magnetic field harmonics, and difficulty in improving torque density in the existing dual-stator tangential excitation vernier permanent magnet motor.

[0037] This invention provides a control method for a load-transfer type, high-overload dual-stator vernier permanent magnet motor as described in any of the above embodiments, comprising: When the motor load is below the load threshold, adjust the current intensity of the inner and outer stator armature windings respectively to concentrate the motor load on the inner stator; when the motor load is greater than or equal to the load threshold, adjust the current intensity of the inner and outer stator armature windings respectively to concentrate the motor load on the outer stator.

[0038] Specifically, the motor provided in this embodiment of the invention has two stator winding structures with different back EMFs and different armature harmonic orders. Compared with the outer stator, the inner stator has a larger no-load back EMF. Therefore, to maximize the torque density, the load can be distributed by adjusting the current intensity flowing through the inner and outer stator armature windings, so that the electrical load is concentrated in the inner stator under low load conditions. Since the inner stator armature harmonic pole pair number is small and the armature response is strong, it is more prone to saturation. As the load increases, when it exceeds the load threshold, the load can be distributed again by adjusting the current intensity flowing through the inner and outer stator armature windings, so that the electrical load is concentrated in the outer stator, thereby migrating the load from the inner stator to the outer stator, so as to alleviate the saturation of the motor under overload conditions and improve the overload capacity of the motor.

[0039] The following example further illustrates the load-transfer type strong overload dual-stator vernier permanent magnet motor provided in the embodiments of the present invention.

[0040] The conventional dual-stator tangentially excited vernier permanent magnet motor (DSSAVPM) has an inner and outer stator pole ratio of 3.5 or 7, respectively, and a rotor pole pair number of 7. For a fair comparison, the load-transferring, high-overload dual-stator vernier permanent magnet motor provided in this embodiment of the invention has the same outer diameter, shaft length, split ratio, permanent magnet quantity, slot fill factor, yoke thickness, total electrical load, number of series turns per phase, and number of parallel branches as the DSSAVPM.

[0041] The design process of the structural parameters of the load-transfer type high overload dual-stator vernier permanent magnet motor provided in this embodiment of the invention includes: (1) Based on the given outer stator outer diameter, optimize the design to obtain the number of rotor pole pairs with the goal of maximizing motor torque. and the pole ratio of the inner and outer stators , ; (2) Based on the number of rotor pole pairs and the pole ratio of the inner and outer stators , Calculate the number of armature winding pole pairs, the number of teeth in the outer stator, and the number of main teeth in the inner stator for the inner and outer stators; (3) Under the rated operating condition where both the inner and outer stator electrical loads are 100A / cm, optimize the magnet size based on the number of teeth of the outer stator and the number of pole pairs of the armature winding of the outer stator; (4) Optimize the inner diameter of the outer stator, the width of the outer stator teeth, the width of the slot and the depth of the slot according to the size of the magnet; calculate the outer diameter of the rotor according to the inner diameter of the outer stator, and calculate the inner diameter of the rotor according to the outer diameter of the rotor; (5) Based on the number of armature winding pole pairs of the outer stator and number of external stator teeth The winding distribution method on the external stator teeth is selected with the goal of the winding coefficient being greater than the winding coefficient threshold. (6) The widths of the first to third auxiliary teeth of the inner stator are obtained by optimizing the design with the goal of maximizing the no-load fundamental back EMF of the motor. , , The groove depth of the tooth groove in the auxiliary tooth structure , , , slot width , ; (7) Select the distribution pattern of the inner stator winding 7 on the inner stator main teeth according to the winding span corresponding to the set of auxiliary tooth parameters that maximize the inner stator torque; (8) The width and length of the main teeth are optimized by maximizing the inner stator torque.

[0042] In this example, the outer stator winding is wound on the outer stator teeth in a distributed winding manner, while the inner stator winding is wound on the main teeth of the inner stator in a concentrated winding manner.

[0043] The electromagnetic performance of the load-transferring, high-overload dual-stator vernier permanent magnet motor provided in this embodiment of the invention is compared with that of the DSSAVPM: Under rated operating conditions of 200 A / cm, the torque of the motor provided in this embodiment of the invention is compared to... PR =3.5 DSSAVPM is improved by 13%, compared to PR The DSSAVPM is improved by 30% for PR=7; under an overload condition of 600 A / cm, the torque of the motor provided by this embodiment of the invention is improved by 6% compared to the DSSAVPM with PR=3.5, and by 73% compared to the DSSAVPM with PR=7. This invention provides an electronic device, including: a computer-readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the method as described in any of the above embodiments.

[0044] This invention provides a computer-readable storage medium storing computer instructions that cause a processor to perform the method described in any of the above embodiments.

[0045] This invention provides a computer program product, including a computer program or instructions, which, when executed by a processor, implement the method described in any of the above embodiments.

[0046] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A load-migration type strong-overload double-stator Vernier permanent magnet motor, characterized in that, It comprises: a shaft (8), an inner stator (6), a rotor (5) and an outer stator (1) coaxially sleeved in sequence from inside to outside along the radial direction; The rotor (5) is embedded with permanent magnet arrays distributed along the tangential and radial directions respectively; the winding electric frequency of the outer stator (1) is three times that of the inner stator (6). The air gap side of the outer stator (1) adopts an open slot structure, and coils are wound on the outer stator teeth; the armature winding pole pair number of the outer stator (1) The outer stator pole ratio Satisfies the relationship The outer stator tooth number Satisfies the relationship ; The rotor pole pair number; The inner stator (6) comprises a stator yoke (61), first auxiliary teeth (62), main teeth (65) and an auxiliary tooth structure; the first auxiliary teeth (62) and the main teeth (65) are symmetrically distributed on the side of the stator yoke (61) in the circumferential direction, and the included angle between any main tooth (65) and any adjacent first auxiliary tooth (62) is The auxiliary tooth structure is an axisymmetric structure arranged on the main teeth, comprising one second auxiliary tooth (63) and two third auxiliary teeth (64), the number of the main teeth and the first and second auxiliary teeth is The number of the third auxiliary teeth is , is a positive integer greater than or equal to 1; the main teeth (65) are wound with coils; the number of pole pairs of the armature winding of the inner stator (1) The ratio of the poles of the inner stator satisfies the relationship The number of the main teeth of the inner stator satisfies the relationship ; The widths of the first to third auxiliary teeth and the slot depth and width of the tooth slot in the auxiliary tooth structure are simulated and optimized to maximize the no-load fundamental back EMF of the motor.

2. The electric machine of claim 1, wherein, The no-load fundamental back EMF of the motor and the inner air gap radius satisfy the relationship: wherein, is the no-load fundamental back EMF, , is the center of the coil, , is the inner air gap radius, is the motor stack length, is the fundamental MMF amplitude, is the motor speed, is the fundamental MMF phase, is the winding span, is the air gap permeance function.

3. The electric machine of claim 2, wherein, The widths of the first to third auxiliary teeth and the slot depth and width of the tooth slot in the auxiliary tooth structure are simulated and optimized to maximize the no-load fundamental back EMF of the motor, including: The widths of the first to third auxiliary teeth and the slot depth and width of the tooth slot in the auxiliary tooth structure are simulated and optimized to maximize the no-load fundamental back EMF of the motor, including: The widths of the first to third auxiliary teeth and the slot depth and width of the tooth slot in the auxiliary tooth structure are simulated and optimized to maximize the no-load fundamental back EMF of the motor, including:

4. The electric machine of claim 1, wherein, The widths and lengths of the main teeth (65) are optimized to maximize the motor torque density.

5. The electric machine of claim 1, wherein, The number of rotor pole pairs And the pole ratio of inner and outer stators , It is obtained by optimizing design aiming at maximum motor torque density according to given outer diameter of outer stator. The magnetic steel size of the rotor (5) is according to the pole pair number of the armature winding of the outer stator and the number of teeth of the outer stator Optimized design is obtained with the goal of maximum motor torque density. The rotor magnet size includes the length and width of the permanent magnets distributed along the tangential and radial directions respectively.

6. The electric machine of claim 5, wherein, The inner diameter of the outer stator (1), the width of the outer stator tooth, the opening slot width and the slot depth are optimized according to the rotor magnet size to maximize the motor torque density.

7. The electric machine of claim 1, wherein, The winding distribution on the outer stator teeth is based on the number of armature winding pole pairs of the outer stator. and number of external stator teeth The winding is selected with the winding coefficient being greater than the winding coefficient threshold as the target; the winding distribution method is either concentrated winding or distributed winding.

8. The electric machine of claim 1, wherein, The winding distribution mode on the main teeth of the inner stator (6) is selected according to the winding span corresponding to the target structure parameter that maximizes the inner stator torque; the winding distribution mode is concentrated winding or distributed winding.

9. A control method of the load-migration type strong-overload double-stator Vernier permanent magnet motor according to any one of claims 1-7, characterized in that, It comprises: When the motor load is lower than the load threshold, adjust the current intensity of the inner and outer stator armature windings respectively to concentrate the motor load on the inner stator; When the motor load is greater than or equal to the load threshold, adjust the current intensity of the inner and outer stator armature windings respectively to concentrate the motor load on the outer stator.

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