Rotor sharing type composite magnetic flux modulation motor pole slot matching design method based on back electromotive force harmonic suppression

Abstract

The invention discloses a rotor sharing type composite magnetic flux modulation motor pole slot matching design method based on back electromotive force harmonic suppression, which comprises the following steps of: establishing a relationship between air gap flux density and motor output torque by using motor back electromotive force as an intermediate variable, and realizing back electromotive force THD performance improvement by reducing air gap flux density time harmonics, therefore, the torque pulsation is reduced, and the overall torque density of the motor is improved. According to the invention, the optimal performance of the rotor sharing type composite magnetic flux modulation motor is realized through reasonable design of pole slot cooperation.

Description

Technical Field

[0001] The present invention relates to the technical field of motor modulation, and in particular to a pole-slot matching design method for a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression. Background Art

[0002] Traditional motor design typically uses air gap flux density as a key parameter. However, for complex rotor-sharing composite flux modulation motors (such as RSC-FM), directly establishing a relationship between air gap flux density and motor output torque is difficult. Multi-port motors in traditional hybrid systems often use a single stator structure. In this structure, the torque-regulating motor windings and the speed-regulating motor windings share the same stator, which can lead to strong coupling between the two windings and generate back-EMF harmonics in the two windings. Back-EMF performance deteriorates significantly when the pole pairs of the two windings are multiples or share a common divisor (other than 1).

[0003] Therefore, how to provide a pole-slot matching design method for a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression has become a technical problem that technicians in this field urgently need to solve. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a pole-slot matching design method for a rotor-sharing composite flux modulation motor based on back-electromotive force harmonic suppression. By rationally designing the pole-slot matching, the optimal performance of the rotor-sharing composite flux modulation motor is achieved.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back-EMF harmonic suppression includes: using the motor back-EMF as an intermediate variable to establish a relationship between air gap flux density and motor output torque, and improving back-EMF THD performance by reducing air gap flux density time harmonics, thereby reducing torque pulsation and improving the overall torque density of the motor.

[0007] Furthermore, the rotor-sharing composite flux modulation motor is split into two parts: a torque-regulated motor and a speed-regulated motor;

[0008] Output torque T of rotor-sharing composite flux modulation motor o Calculate using formula (2), where T oi Indicates the torque provided by the speed regulating motor, T os Represents the torque provided by the torque-regulated motor:

[0009] T o =T oi +T os (2).

[0010] Furthermore, the operation of the speed-regulated motor must meet the following conditions: the electrical frequency of the inner armature winding, the mechanical speed of the inner rotor, and the mechanical speed of the permanent magnet outer rotor should follow the relationship shown in formula (1):

[0011] 60f iw =|P pm Ω pm -P ir Ω ir | (1)

[0012] Where f iw Indicates the electrical frequency of the inner armature winding, P ir and Ω ir Represent the number of pole pairs and mechanical speed of the inner rotor, P pm and Ω pm They represent the number of pole pairs and mechanical speed of the permanent magnet outer rotor respectively;

[0013] By adjusting the electrical frequency of the inner armature winding, the speed of the permanent magnet outer rotor can be smoothly controlled, thereby realizing the continuously variable speed function of the hybrid system.

[0014] Furthermore, the speed regulating motor reduces the back electromotive force harmonics caused by time harmonics by reducing the harmonic order of the inner air gap magnetic flux density and the same spatial order of the inner armature winding function; optimization measures include reasonably selecting the pole-slot matching scheme, adopting distributed winding or adjusting the winding distribution coefficient, optimizing the short-distance coefficient, and designing harmonic weakening winding when necessary.

[0015] Furthermore, the inner stator of the speed-regulating motor should adopt an integer-slot distributed winding with a low dipole pair number to ensure that the amplitude of the higher-order harmonics of the winding function is extremely low under this pole pair number, and the higher-order harmonics are all even numbers, thereby significantly reducing the back-electromotive force harmonics; in order to avoid the interaction between the magnetic tuning ring and the permanent magnet and the higher-order harmonics of the inner stator winding function to generate back-electromotive force harmonics, the pole pair number of the magnetic tuning ring and the permanent magnet rotor should be selected as an odd number; the pole pair number of the dual rotor should be mutually prime on the premise of being an odd number to ensure that there is no common divisor with the inner armature winding, thereby further reducing the generation of back-electromotive force harmonics.

[0016] Furthermore, the inner stator is designed as a semi-closed slot structure to minimize its modulation function; the number of inner stator teeth is the same as the number of outer stator slots to reduce the complexity of the air gap magnetic density harmonics generated by the modulation effect.

[0017] Furthermore, when designing a torque-regulated motor, the back-electromotive force amplitude should be optimized as much as possible within a limited space to enhance its torque output capability. According to formula (3), there are two main ways to increase the back-electromotive force of the armature winding: one is to increase the amplitude of the air gap flux density, and the other is to increase the matching number of the winding function and the spatial harmonic order in the air gap flux density through pole-slot matching.

[0018]

[0019] Where, ψ m (t) is the no-load magnetic flux, k w is the armature winding factor, B m is the no-load air gap flux density of the motor, N A is the motor A phase winding function, N Au The amplitude of the uth magnetic harmonic winding function, P s is the number of armature winding pole pairs, E is the back electromotive force of the armature winding; θ is the spatial mechanical angle, t is the time, N A is the A-phase winding function.

[0020] Furthermore, a fractional-slot concentrated winding design is adopted for the external armature winding to maximize the interaction between the air gap flux harmonics and the winding function harmonics; this design optimizes the spatial distribution of the winding, so that more magnetic flux is effectively utilized, thereby significantly improving the back electromotive force amplitude.

[0021] Furthermore, in order to reduce the coupling of the dual armature windings, the pole pairs of the inner and outer armature windings should be selected to be non-multiples, and there should be no common factors other than 1, so as to avoid the dual winding coupling introducing time harmonics in the inner and outer air gap magnetic flux, thereby causing back electromotive force harmonics.

[0022] Beneficial effects of the present invention:

[0023] The permanent magnet outer rotor of the present invention serves as the only mechanical output port of the motor, while the inner rotor is connected to the internal combustion engine (ICE) to realize the input and output of mechanical power. The inner and outer armature windings are powered by dual power supplies through an inverter, which can convert electrical energy into mechanical energy for output, and also convert mechanical energy into electrical energy and store it in a battery. The dual-stator structure is adopted. This structural design can effectively enhance the air gap magnetic flux amplitude, thereby improving the back electromotive force and torque output capabilities. In addition, this structural design realizes efficient energy conversion and power output of the motor in the hybrid power system through rotor sharing and pole-slot matching optimization, thereby achieving the best performance of the rotor-sharing composite flux modulation motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a topological diagram of the rotor-sharing composite flux modulation motor of the present invention.

[0025] Figure 2Schematic diagram of internal and external back electromotive force THD of six rotor-sharing composite flux modulation motors with different structures;

[0026] Figure 3 This is the schematic diagram of 24-I air gap magnetic density FFT harmonics;

[0027] Figure 4 Schematic diagram of the electromagnetic performance of the optimal topology 24-I. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0029] Reference Attachment Figure 1 The present invention provides a method for designing pole-slot coordination for a rotor-sharing composite flux modulation motor based on back-EMF harmonic suppression. The method includes: using the motor's back-EMF as an intermediate variable to establish a relationship between air-gap flux density and the motor's output torque. This method improves back-EMF THD performance by reducing air-gap flux time harmonics, thereby reducing torque ripple and improving the motor's overall torque density. This rotor-sharing composite flux modulation motor is suitable for hybrid power systems and features a dual mechanical and dual electrical port structure. By rationally designing the pole-slot coordination, optimal performance for this type of motor is achieved.

[0030] A shared rotor composite flux modulation motor consists of two parts: a torque-regulated motor and a speed-regulated motor. The shared rotor composite flux modulation motor consists of two components: the outer stator, outer armature winding, and permanent magnet outer rotor form a permanent magnet synchronous motor (PMSM), whose primary function is to improve the motor's overall torque density and is referred to as a torque-regulated motor. The inner stator, inner armature winding, inner rotor, and permanent magnet outer rotor form a magnetic gear motor (MGM), whose primary function is to achieve continuously variable speeds in hybrid systems and is referred to as a speed-regulated motor. The permanent magnet outer rotor serves as the motor's sole mechanical output port, while the inner rotor is connected to the internal combustion engine (ICE) for mechanical power input and output. The inner and outer armature windings are powered by dual power supplies through an inverter, converting electrical energy into mechanical energy for output and converting mechanical energy into electrical energy for storage in a battery. This design, through rotor sharing and optimized pole-slot coordination, achieves efficient energy conversion and power output in hybrid systems.

[0031] The operation of the speed-regulated motor must meet the following conditions: the electrical frequency of the inner armature winding, the mechanical speed of the inner rotor, and the mechanical speed of the permanent magnet outer rotor should follow the relationship shown in formula (1):

[0032] 60f iw =|P pm Ω pm -P ir Ω ir | (1)

[0033] Where f iw Indicates the electrical frequency of the inner armature winding, P ir and Ω ir Represent the number of pole pairs and mechanical speed of the inner rotor, P pm and Ω pm They represent the number of pole pairs and mechanical speed of the permanent magnet outer rotor respectively.

[0034] When deeply analyzing the operating principle of the rotor-sharing composite flux modulation motor (RSC-FM), it can be divided into two parts: the torque regulation motor and the speed regulation motor for research. For the speed regulation motor, the inner rotor is connected to the internal combustion engine, and its speed is usually in a specific range to ensure that the internal combustion engine operates at optimal efficiency. By adjusting the electrical frequency of the inner armature winding, the speed of the permanent magnet outer rotor can be smoothly controlled, thereby realizing the stepless speed change function of the hybrid system. For the torque regulation motor, since the RSC-FM is used as a direct drive motor and the output torque of the speed regulation motor is relatively low, a permanent magnet synchronous motor is coupled to improve the overall torque density. This design ensures that the motor has sufficient torque output capacity while operating efficiently. The output torque T of the rotor-sharing composite flux modulation motor o Calculate using formula (2), where T oi Indicates the torque provided by the speed regulating motor, T os Represents the torque provided by the torque-regulated motor:

[0035] T o =T oi +T os (2).

[0036] As the core power component of hybrid power systems, the rotor-shared composite flux modulation motor (RSC-FM) must be designed to fully consider the low-speed, high-torque requirements in direct-drive applications. To achieve this, the number of stator slots should be small (e.g., 24 or 36), while the number of permanent magnet pole pairs should be high to meet the low-speed, high-torque performance requirements. During the design process, the RSC-FM can be split into two independent components: a torque-regulating motor and a speed-regulating motor. The effects of electromagnetic coupling can then be comprehensively considered to optimize overall performance.

[0037] Traditional motor design typically uses air gap flux density as a key parameter. However, for complex specialized motors (such as RSC-FM), directly establishing a relationship between air gap flux density and motor output torque is difficult. To address this issue, this paper proposes a design method that uses the motor's back EMF as an intermediate parameter. By correlating air gap flux density with motor torque performance through back EMF, this method effectively connects electromagnetic parameters with mechanical properties, providing a versatile and efficient solution for RSC-FM design.

[0038] For the motor back electromotive force, it can usually be expressed as the derivative of the motor's no-load flux with respect to time. The no-load flux can be obtained by integrating the product of the air gap flux density and the winding function, as shown in formula (3):

[0039]

[0040] Where, ψ m (t) is the no-load magnetic flux, k w is the armature winding factor, B m is the no-load air gap flux density of the motor, N A is the motor A phase winding function, N Au The amplitude of the uth magnetic harmonic winding function, P s is the number of armature winding pole pairs, E is the back electromotive force of the armature winding; θ is the spatial mechanical angle, t is the time, N A is the A-phase winding function.

[0041] According to formula (3), since the integral variable is the spatial mechanical angle θ, for the motor's no-load flux, the integral result is not zero and effective flux can be generated only when the spatial harmonic order in the motor's no-load air gap flux is consistent with the spatial harmonic order of the armature winding function.

[0042] Based on the above analysis, the function of a torque-regulated motor is to improve the torque density of a rotor-shared composite flux modulation motor (RSC-FM). Therefore, when designing a torque-regulated motor, the back EMF amplitude should be optimized as much as possible within a limited space to enhance its torque output capability. According to formula (3), there are two main ways to increase the armature winding back EMF: one is to increase the amplitude of the air gap flux density, and the other is to increase the matching frequency between the winding function and the spatial harmonic order in the air gap flux density through pole-slot matching.

[0043] Specifically, the external air gap flux density, after stator tooth modulation, has a high harmonic content. Therefore, a fractional-slot concentrated winding design is used for the external armature winding to maximize the interaction between the air gap flux density harmonics and the winding function harmonics. This design optimizes the spatial distribution of the windings, effectively utilizing more magnetic flux and significantly improving the back EMF amplitude. Furthermore, the RSC-FM utilizes a dual-stator structure, which effectively enhances the air gap flux density amplitude, thereby improving back EMF and torque output capabilities.

[0044] As for the speed regulating motor, as a magnetic gear motor, it is mainly responsible for realizing the electronic stepless speed change function. Due to this characteristic, the torque fluctuation of the rotor-sharing composite flux modulation motor mainly comes from the speed regulating motor. The output torque of the motor is composed of three parts: electromagnetic torque, cogging torque and reluctance torque. Since the rotor-sharing composite flux modulation motor targeted by the present invention is a surface-mounted motor, its reluctance torque content is relatively low, and the cogging torque is the torque component generated by the mismatch of the motor structural parameters, which can be effectively suppressed by optimizing the motor structural parameters. Therefore, the present invention focuses on the torque fluctuation caused by electromagnetic torque, that is, the mechanical power fluctuation caused by the motor electric power, and the electric power fluctuation is mainly caused by the motor back electromotive force harmonics and current harmonics.

[0045] For the inner air gap, compared with the outer air gap where the magnetic ring is in motion and not in a stationary state like the outer stator, the inner air gap magnetic flux density will contain both time harmonic and space harmonic components. The expression of the inner air gap magnetic flux density is shown in formula (4):

[0046]

[0047] Where B(θ,t) represents the air gap magnetic flux density, h represents the magnetomotive force order, and P pm Indicates the number of permanent magnet pole pairs, Ω pm Indicates the permanent magnet rotor speed, p ir Indicates the number of inner rotor pole pairs, Ω ir Inner rotor speed, F h represents the h-th order magnetomotive force coefficient, λ i represents the i-th permeability coefficient.

[0048] From formula (4), we can see that since both magnetomotive force and permeance are functions of time t, the inner air gap magnetic flux density will not only have spatial harmonics but also (hP pm Ω pm ±ip ir Ω ir) order time harmonics. According to formula (3), the fundamental wave of the air gap flux density generates the fundamental wave of the back electromotive force, while the time harmonics lead to the back electromotive force harmonics, which in turn cause the motor torque pulsation. Due to the high harmonic content of the inner air gap flux density, the sinusoidal characteristics of the back electromotive force should be maintained as much as possible when designing the inner armature winding to reduce harmonic distortion. Specifically, the number of harmonics with the same spatial order of the inner air gap flux density and the inner armature winding function should be reduced to reduce the back electromotive force harmonics caused by time harmonics. Optimization measures include reasonably selecting the pole-slot matching scheme, adopting distributed windings or adjusting the winding distribution coefficient, optimizing the short-distance coefficient, and designing harmonic weakening windings when necessary to improve the purity of the back electromotive force, reduce torque pulsation, and ensure stable system operation.

[0049] Specifically, the inner stator should utilize an integer-slot distributed winding with a low dipole pair number to ensure that the amplitude of the higher-order harmonics of the winding function is extremely low at this pole pair number, and that all higher-order harmonics are even, thereby significantly reducing back-EMF harmonics. To prevent the interaction between the magnetic ring and permanent magnets and the higher-order harmonics of the inner stator winding function, which could generate back-EMF harmonics, the pole pair number of the magnetic ring and permanent magnet rotor should be odd. Furthermore, the pole pair number of the dual rotor should be coprime, while still odd, to ensure that there is no common divisor with the inner armature winding, further reducing the generation of back-EMF harmonics.

[0050] Furthermore, because the inner rotor (magnetic ring) plays the primary modulation role in speed-regulated motors, the inner stator should be designed with a semi-closed slot structure to minimize its modulation function. However, in practice, some permeance fluctuations still exist. To further minimize the impact of the inner stator teeth, the number of inner stator teeth should be the same as the number of outer stator slots. This reduces the complexity of the air gap flux harmonics generated by the modulation effect and avoids the introduction of additional air gap flux harmonic orders.

[0051] To reduce coupling between the dual armature windings, the pole-pair numbers of the inner and outer armature windings should be non-multiples, with no common factors other than 1. This prevents the dual-winding coupling from introducing time harmonics into the inner and outer air gap flux density, which in turn triggers back-EMF harmonics. Furthermore, the RSC-FM motor proposed in this invention utilizes a dual-stator structure, effectively achieving magnetic isolation between the dual armature windings and reducing mutual coupling between them, thereby reducing back-EMF harmonics.

[0052] The permanent magnet outer rotor of the present invention serves as the only mechanical output port of the motor, while the inner rotor is connected to the internal combustion engine (ICE) to realize the input and output of mechanical power. The inner and outer armature windings are powered by dual power supplies through an inverter, which can convert electrical energy into mechanical energy for output, and also convert mechanical energy into electrical energy and store it in a battery. The dual-stator structure is adopted. This structural design can effectively enhance the air gap magnetic flux amplitude, thereby improving the back electromotive force and torque output capabilities. In addition, this structural design realizes efficient energy conversion and power output of the motor in the hybrid power system through rotor sharing and pole-slot matching optimization, thereby achieving the best performance of the rotor-sharing composite flux modulation motor.

[0053] In order to verify the effectiveness of the above design principles, the present invention designed six comparative motor models with different pole-slot combinations. Table 1 shows the internal and external back electromotive force THD of the rotor-sharing composite flux modulation motors with six different topologies. Among them, 24-I and 36-I follow the design principles, while 24-II, 24-III, 24-IV and 36-II violate these principles in some aspects. These models were compared and analyzed using finite element simulation software, focusing on the back electromotive force characteristics of the internal and external armature windings, and using fast Fourier transform (FFT) to analyze their total harmonic distortion (THD) content. The results are as follows: Figure 2 shown.

[0054] Motor type Number of outer and inner stator slots Permanent magnet pole pairs Number of poles of magnetic ring 24-Ⅰ 24,24 11 13 24-Ⅱ 24,24 10 12 24-Ⅲ 24,24 11 12 24-Ⅳ 24,12 11 13 36-Ⅰ 36,36 17 21 36-Ⅱ 36,36 17 19

[0055] Analysis shows that 24-I and 36-I have the lowest THD values, indicating the lowest back-EMF harmonic content. In contrast, 24-II has the highest THD value. This is because when the number of dual rotor pole pairs and the number of pole pairs of the inner and outer armature windings are both even, the coupling effect between the pole pairs significantly increases the harmonic content. While the THD values ​​of 24-III and 24-IV are lower than that of 24-II, they still exhibit a certain degree of harmonic distortion. Specifically, in 24-III, the inner stator winding has only one pole pair, resulting in a multiple of the number of dual rotor pole pairs and the number of pole pairs of the outer stator armature winding, which causes harmonic distortion. In 24-IV, the number of teeth in the inner stator (12 teeth) differs from that in the outer stator, introducing new air gap flux time harmonics, which leads to back-EMF distortion. Both the 36-I and 36-II models have low harmonic content. However, the 36-I's inner stator armature winding has four pole pairs, compared to the 36-II's two pole pairs. This results in higher-order harmonics and fewer in number, further reducing harmonics. However, because both the 36-I and 36-II use a 36-slot stator structure, the stator teeth and yoke are thin, making them prone to saturation under high loads, affecting modulation and reducing performance.

[0056] Figure 3 (a) Figure 3 (b) and Figure 4The electromagnetic performance of the optimal topology 24-I was demonstrated. The results show that the outer air gap flux density contains multiple harmonics, generating a large back EMF, while the inner air gap flux density has fewer harmonics, thereby reducing back EMF harmonics and meeting design requirements. Under rated operating conditions, the inner and outer rotor output torques are -226.8 Nm and 768.4 Nm, respectively, with torque ripple of 8.36% and 3.82%, respectively.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression, characterized in that: include: By using the motor back electromotive force as an intermediate variable, the relationship between the air gap flux density and the motor output torque is established. By reducing the time harmonics of the air gap flux density, the back electromotive force THD performance is improved, thereby reducing the torque pulsation and improving the overall torque density of the motor.

2. The method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 1, characterized in that: The rotor-sharing composite flux modulation motor is divided into two parts: a torque-regulated motor and a speed-regulated motor; Output torque T of rotor-sharing composite flux modulation motor o Calculate using formula (2), where T oi Indicates the torque provided by the speed regulating motor, T os Represents the torque provided by the torque-regulated motor: T o =T oi +T os (2)。 3. The method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 2, characterized in that: The operation of the speed-regulated motor must meet the following conditions: the electrical frequency of the inner armature winding, the mechanical speed of the inner rotor, and the mechanical speed of the permanent magnet outer rotor should follow the relationship shown in formula (1): 60f iw =|P pm Oh pm -P ir Oh ir | (1) Where f iw Indicates the electrical frequency of the inner armature winding, P ir and Ω ir Represent the number of pole pairs and mechanical speed of the inner rotor, P pm and Ω pm They represent the number of pole pairs and mechanical speed of the permanent magnet outer rotor respectively; By adjusting the electrical frequency of the inner armature winding, the speed of the permanent magnet outer rotor can be smoothly controlled, thereby realizing the continuously variable speed function of the hybrid system.

4. A method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 2 or 3, characterized in that: The speed regulation motor reduces the back electromotive force harmonics caused by time harmonics by reducing the harmonic order of the inner air gap flux density and the same spatial order of the inner armature winding function; optimization measures include reasonably selecting the pole-slot matching scheme, adopting distributed winding or adjusting the winding distribution coefficient, optimizing the short-distance coefficient, and designing harmonic weakening winding when necessary.

5. The method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 4, characterized in that: The inner stator of the speed-regulating motor should adopt an integer-slot distributed winding with a low dipole pair number to ensure that the amplitude of the higher-order harmonics of the winding function is extremely low at this pole pair number, and the higher-order harmonics are all even numbers, thereby significantly reducing the back-electromotive force harmonics; in order to avoid the interaction between the magnetic tuning ring and the permanent magnet and the higher-order harmonics of the inner stator winding function to generate back-electromotive force harmonics, the pole pair number of the magnetic tuning ring and the permanent magnet rotor should be selected as an odd number; the pole pair number of the dual rotor should be mutually prime under the premise of being an odd number to ensure that there is no common divisor with the inner armature winding, thereby further reducing the generation of back-electromotive force harmonics.

6. The method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 5, characterized in that: The inner stator is designed as a semi-closed slot structure to minimize its modulation function; The number of inner stator teeth is the same as the number of outer stator slots to reduce the complexity of the air gap magnetic flux harmonics generated by the modulation effect.

7. The method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 6, characterized in that: When designing a torque-regulated motor, the back-electromotive force amplitude should be optimized as much as possible within a limited space to enhance its torque output capability. According to formula (3), there are two main ways to increase the back-electromotive force of the armature winding: one is to increase the amplitude of the air gap flux density, and the other is to increase the matching number of the winding function and the spatial harmonic order in the air gap flux density through pole-slot matching. Where, ψ m (t) is the no-load magnetic flux, k w is the armature winding factor, B m is the no-load air gap flux density of the motor, N A is the motor A phase winding function, N Au The amplitude of the uth magnetic harmonic winding function, P s is the number of armature winding pole pairs, E is the back electromotive force of the armature winding; θ is the spatial mechanical angle, t is the time, N A is the A-phase winding function.

8. The method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 7, characterized in that: The external armature winding adopts a fractional-slot concentrated winding design to maximize the interaction between the air gap flux harmonics and the winding function harmonics. This design optimizes the spatial distribution of the winding, allowing more magnetic flux to be effectively utilized, thereby significantly improving the back electromotive force amplitude.

9. The method for designing pole-slot coordination of a rotor-sharing composite flux modulation motor based on back electromotive force harmonic suppression according to claim 8, characterized in that: In order to reduce the coupling of the dual armature windings, the pole pairs of the inner and outer armature windings should be selected to be non-multiples, and there should be no common factors other than 1, so as to avoid the dual winding coupling introducing time harmonics in the inner and outer air gap magnetic flux, thereby causing back electromotive force harmonics.

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