A method for approximate symmetrization of an electric machine with an asymmetric winding layout

Abstract

The application discloses a kind of approximate symmetrization design methods suitable for motor asymmetric winding layout, first by introducing fundamental wave magnetic motive force deviation vector, construct three-phase motor asymmetric winding layout approximate symmetrization design criterion;Then with the slot phasor corresponding to the upper layer edge slot conductor of three-phase asymmetric winding as set, and using the genetic algorithm with elite strategy to generate the resultant vector that makes fundamental wave magnetic motive force deviation vector as close to zero as possible;Finally, with A phase as fixed phase, according to the distribution of resultant vector adjustment B phase and C phase slot phasor along the stator circumference, and then determine the approximate symmetrization design scheme of asymmetric winding layout under different pole-slot matching.The application perfects the approximate symmetrization design theory of three-phase asymmetric winding, which can reduce the blindness of three-phase motor asymmetric winding layout design to some extent, and can effectively realize the approximate symmetrization design of three-phase motor asymmetric winding layout under different pole-slot matching, with strong universality and easy implementation.

Description

Technical Field

[0001] This invention belongs to the field of motor winding layout design technology, specifically relating to an approximate symmetry design method applicable to asymmetric motor winding layouts. Background Technology

[0002] Currently, there are three main methods for approximate symmetry design of asymmetric winding layouts for motors: the first is the slot offset method, as reported in the literature [Li Wenxuan. Unconventional winding design and torque performance analysis of permanent magnet assisted synchronous reluctance motor. Jiangsu: Jiangsu University, 2023]; the second is the multi-layer winding method, as proposed in the Chinese invention patent application with publication number CN108880019A, which proposes a six-layer winding phase method applicable to a 39-slot 12-pole three-phase permanent magnet synchronous motor; the third is the three-layer three-phase winding method, as reported in the literature [Y. Demir, E Yolacan, AM EL-Refaie and M. Aydin. Investigation of different winding configurations and displacements of a nine-phase permanent-magnet-synchronous motor with unbalanced AC winding structure. IEEE Transactions on Industry Applications, 2019, 55(4): 3660-3670].

[0003] The above research methods can improve the symmetry of the asymmetric winding layout of the motor, but the slot offset method will lead to a decrease in the torque density of the motor, affecting the motor efficiency, heat dissipation and other performance. The multi-layer winding method is mainly suitable for the near-symmetrical design of the winding with specific pole slots and 39 slots and 12 poles. Moreover, the implementation of this method requires the continuous winding of multiple three-phase windings, which increases the complexity and time of winding inlay to a certain extent. The three-layer three-group winding method is more suitable for the near-symmetrical design of the winding layout of nine-phase motors.

[0004] Therefore, for the widely used three-phase motors, there is still a lack of relevant theoretical support for a universal asymmetric winding approximation design method that can fully meet their requirements for high torque density and low torque ripple under different pole-slot ratios. Thus, further in-depth research and exploration are needed. Summary of the Invention

[0005] In view of the above-mentioned technical problems existing in the prior art, the present invention provides an approximate symmetrical design method for asymmetric winding layout of motors, which can reduce the blindness of asymmetric winding layout design of three-phase motors to a certain extent, and can effectively realize the approximate symmetrical design of asymmetric winding layout of three-phase motors under different pole-slot ratios.

[0006] An approximate symmetry design method suitable for asymmetric winding layouts of electric motors includes the following steps: (1) Introduce the fundamental magnetomotive force deviation vector to construct an approximate symmetry design criterion for the asymmetric winding layout of a three-phase motor; (2) Based on the design principle of approximate symmetry of the asymmetric winding layout of the three-phase motor, a composite vector is generated that makes the fundamental magnetomotive force deviation vector as close to zero as possible; (3) Using phase A as the fixed phase, and adjusting the distribution of the slot phasors of phase B and phase C along the stator circumference according to the composite vector, the approximate symmetrical design scheme of the asymmetric winding layout of the three-phase motor is finally determined.

[0007] Furthermore, the fundamental magnetomotive force deviation vector is generated by the fundamental composite magnetomotive force vector of the three-phase symmetrical winding and the three-phase asymmetrical winding, and the fundamental magnetomotive force deviation vector of phase A is... =0, B-phase fundamental magnetomotive force deviation vector = - C-phase fundamental magnetomotive force deviation vector = - ,in The B-phase fundamental wave composite magnetomotive force vector of the three-phase symmetrical winding. The B-phase fundamental wave composite magnetomotive force vector of the three-phase asymmetrical winding. The C-phase fundamental wave composite magnetomotive force vector of the three-phase symmetrical winding. It is the composite magnetomotive force vector of the C-phase fundamental wave of the three-phase asymmetrical winding.

[0008] Furthermore, the expression for the design criterion of approximate symmetry of the asymmetric winding layout of the three-phase motor in step (1) is as follows:

[0009] ,

[0010] in: F ΔΦ The fundamental magnetomotive force deviation vector of phase B amplitude, θ Δ The fundamental magnetomotive force deviation vector of phase B The initial phase angle in space,f D The effective values ​​of the major and minor axes of the elliptical trajectory of the fundamental synthesized magnetomotive force generated by winding asymmetry are given. F + Let be the amplitude of the counterclockwise rotating component in the fundamental rotating magnetomotive force generated by winding asymmetry. F - It represents the amplitude of the clockwise rotation component in the fundamental rotating magnetomotive force generated by winding asymmetry.

[0011] Furthermore, the expression for the synthesized vector in step (2) is as follows:

[0012] in: In order to make and The composite vectors that are as equal as possible, (Δ x ΔB'B , Δ y ΔB'B ) is the composite vector coordinates a i =[ x ai , y ai ] T , b i =[ x bi , y bi ] T and c i =[ x ci , y ci ] T The first of phases A, B, and C respectively i One slot phasor, x ai and y ai Phase A, number 1 i The projected coordinates of each slot phasor in the x-axis and y-axis directions. x bi and y bi They are respectively phase B, number 1 i The projected coordinates of each slot phasor in the x-axis and y-axis directions. x ci and y ci The C phase number i The projected coordinates of each slot phasor in the x-axis and y-axis directions.i =1,2,…, Q / 3, Q This refers to the number of stator slots of the motor. N c It is half the number of conductors per slot in the initial scheme; l 1, l 2, l 3,…, l 2Q A set of positive integers is used to determine the number of winding layers in the motor, which essentially corresponds to 2. Q The number of coil turns increased or decreased for each slot conductor is obtained by optimization using a genetic algorithm with an elite strategy, based on the design principle of approximate symmetry of the asymmetric winding layout of a three-phase motor.

[0013] Furthermore, based on the design principle of approximating symmetry in the asymmetrical winding layout of a three-phase motor, the B-phase fundamental magnetomotive force deviation vector... The expression is as follows:

[0014] in: θ The electrical angle is along the inner circumferential surface of the stator. ω Angular frequency, t Indicates time, Δ x bb' = x b - x b' Δ y bb' = y b - y b' , x b and y b These are the composite magnetomotive force vectors of the B-phase fundamental wave. Projected coordinate values ​​in the x-axis and y-axis directions. x b' and y b' These are the composite magnetomotive force vectors of the B-phase fundamental wave. Projected coordinate values ​​in the x-axis and y-axis directions. F ΔΦ The fundamental magnetomotive force deviation vector of phase B amplitude, θ Δ The fundamental magnetomotive force deviation vector of phase B The initial phase angle in space.

[0015] Furthermore, the amplitude F ΔΦand initial phase angle θ Δ The expression is as follows:

[0016] Furthermore, in step (3), a set of positive integers determined by the genetic algorithm... l 1, l 2, l 3,…, l 2Q Adjust the distribution of the B-phase slot phasor along the stator circumference; then determine the slot phasor number X to be adjusted in phase C using the following formula. ci This allows for the adjustment of the distribution of the corresponding slot phase quantity along the stator circumference to make... and The difference should be as close to 0 as possible, that is, the C-phase fundamental magnetomotive force deviation vector. It tends to be 0;

[0017] in: α 1 represents the tank phase quantity b 1. Initial phase angle in space, p Let be the number of pole pairs of the motor, and mod[ ] represents the modulo operation.

[0018] A computer device includes a memory and a processor, wherein the memory stores a computer program and the processor executes the computer program to implement the above-described approximate symmetry design method applicable to asymmetric winding layouts of motors.

[0019] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described approximate symmetry design method applicable to asymmetric winding layouts of motors.

[0020] This invention introduces the concept of "fundamental magnetomotive force deviation vector" to construct an approximate symmetry design criterion for the asymmetric winding layout of a three-phase motor, improves the approximate symmetry design theory of three-phase asymmetric windings, and provides an approximate symmetry design scheme for a three-phase asymmetric winding layout with good symmetry. To a certain extent, this can reduce the blindness in the design of asymmetric winding layouts of three-phase motors and can effectively realize the approximate symmetry design of asymmetric winding layouts of three-phase motors under different pole-slot ratios. Therefore, the method of this invention has strong versatility and ease of implementation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the fundamental wave composite magnetomotive force distribution of the 21-slot, 18-pole three-phase asymmetric winding in an embodiment of the present invention.

[0022] Figure 2This is a star-shaped diagram of the slot electromotive force of the initial scheme of the 21-slot 18-pole three-phase asymmetrical winding motor in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the winding layout structure of the initial scheme of the 21-slot 18-pole three-phase asymmetric winding motor in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the winding layout structure of a 21-slot, 18-pole three-phase motor with good symmetry, obtained after design and adjustment according to the embodiments of the present invention. Detailed Implementation

[0025] To describe the present invention in more detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] This invention provides an approximate symmetry design method for asymmetrical winding layouts of three-phase motors. The method uses the slot phasors corresponding to the upper-layer side slot conductors of the asymmetrical three-phase winding as a set, and utilizes the existing known technology of a "genetic algorithm with an elite strategy" to generate a synthetic vector that makes the fundamental magnetomotive force deviation vector as close to zero as possible, thereby achieving an approximate symmetry design for the asymmetrical winding layout of the three-phase motor. Specifically, it includes the following steps: Step 1: Introduce the concept of "fundamental magnetomotive force deviation vector" to construct an approximate symmetry design criterion for the asymmetric winding layout of a three-phase motor.

[0027] For three-phase asymmetrical windings, since the coils connected by the windings are not perfectly symmetrical, the phase difference in space between each phase will have a slight deviation from 120° electrical angle. Generally, for ease of discussion, the axis of the fundamental magnetomotive force (MMF) of phase A winding is set horizontally to the right along the x-axis, ensuring that the fundamental MMFs of phases B and C are symmetrical about the fundamental MMF of phase A; that is, the amplitudes of the fundamental MMFs of phases B and C are the same, and the angles between phases B and C and phase A are equal but not equal to 120° electrical angle. Simultaneously, this invention introduces the concept of a "fundamental MMF deviation vector." , and It is generated by the fundamental wave combined magnetomotive force vector of the three-phase symmetrical winding and the three-phase asymmetrical winding, and satisfies =0, = - =( x b , y b )-( x b' , y b' )=( x b -x b' , y b - y b' ), = - =( x c , y c )-( x c' , y c' )=( x c - x c' , y c - y c' Therefore, the fundamental wave of the pulsating magnetomotive force of each phase winding of a three-phase asymmetrical winding motor can be expressed as: (1) In the formula: θ The electric angle is along the inner circumferential surface of the stator; , and ∠AOC is the fundamental amplitude of the pulsating magnetomotive force of the three-phase symmetrical winding; ∠AOC is the angle between the axes of the fundamental magnetomotive forces of the A and C phase windings; ∠AOB is the angle between the axes of the fundamental magnetomotive forces of the A and B phase windings, and satisfies ∠AOC=∠AOB. f A1 ( t , θ ), f B1 ( t , θ ), f C1 ( t , θ ) is the fundamental wave of the pulsating magnetomotive force of a three-phase symmetrical winding, and Δ f A1 ( t , θ ), Δ f B1 ( t , θ ), Δ f C1 ( t , θ ) represents the fundamental magnetomotive force deviation vector. , and The representation functions are: (2) In the formula: F Φ1 This represents the fundamental amplitude of the pulsating magnetomotive force in each phase of the symmetrical winding. F ΔΦ The fundamental magnetomotive force deviation vectors of phase B and phase C and The amplitude; θ Δ The fundamental magnetomotive force deviation vector The initial phase angle in space.

[0028] Substituting equation (2) into equation (1), we can derive the fundamental composite magnetomotive force of the three-phase asymmetrical winding motor as: (3) In the formula: F s1 ( t , θ The fundamental rotating magnetomotive force is positive, and the rotation direction is counterclockwise. F s2 ( t , θ The fundamental rotating magnetomotive force (MF) is in the reverse direction, rotating clockwise. Furthermore, this equation shows that the amplitude trajectory of the fundamental rotating MF generated by the winding asymmetry is an ellipse, and its trajectory equation can be expressed as: (4) According to electrical machinery theory, the fundamental component of a three-phase asymmetrical winding motor is synthesized into a magnetomotive force component. F s1 ( t , θ ), F s2 ( t , θ ) and the fundamental wave of rotor magnetomotive force F r ( t , θ The interaction will produce the average torque of the motor. T avg With second harmonic torque T 2. The calculation formulas for both are as follows: (5) (6) In the formula: D The diameter of the air gap; L The length of the iron core; g This is the air gap length; F r1denoted as the fundamental amplitude of the rotor magnetomotive force; μ0 is the vacuum permeability.

[0029] Combining equations (5) and (6), it can be analyzed that only when ( F + + F - )and( F + - F - Only when both decrease and approach 0 can the fundamental synthesized magnetomotive force of the three-phase asymmetrical winding infinitely approach a circular rotating magnetic field, without significantly reducing the average torque and effectively suppressing the second harmonic torque. The main reason is that when ( F + + F - )and( F + - F - When all of them tend to 0, that is: (7) Then by simply adding and subtracting, we can obtain: (8) Therefore, in order to measure ( F + + F - )and( F + - F - The overall effective magnitude of the two data points is evaluated using the root mean square (RMS) value. The closer this value is to 0, the more symmetrical the fundamental rotating magnetomotive force of the three-phase windings of the asymmetrical winding motor is. (9) Equation (9) is the design criterion for approximating the symmetry of a three-phase asymmetrical winding layout. f D As the magnetomotive force (MOF) approaches zero, the closer the three-phase fundamental composite magnetomotive force of the motor is to a circular rotating magnetic field, the more symmetrical the fundamental rotating MOF of the three-phase windings, and the smaller the second harmonic torque. This design principle can achieve an approximate symmetrical design of the asymmetrical winding layout without significantly reducing the average torque of the motor, and effectively improve the motor's torque output performance.

[0030] Step 2: Generate a composite vector that makes the fundamental magnetomotive force deviation vector as close to zero as possible.

[0031] Taking phase A as the fixed phase, the distribution of slot phase quantities of phases B and C along the stator circumference is adjusted. The slot phase quantities corresponding to the upper side slot conductors of phases A, B, and C are used as a set to form a composite vector. Since the coefficients of each component in the composite vector are random, a composite layer winding layout structure will be formed by simultaneously embedding three phase windings in one slot. The design method of this winding layout structure is as follows: First, the set of slot phase quantities corresponding to the upper-layer side slot conductors of phases A, B, and C is used to construct a set containing... Q A vector group of two-dimensional column vectors H The matrix formed by them is: (10) In the formula: a i =[ x ai , y ai ] T , b i =[ x bi , y bi ] T and c i =[ x ci , y ci ] T The first of phases A, B, and C respectively i One slot phasor; x ai , y ai Phase A, number 1 i The projection of each slot phasor in the x-axis and y-axis directions; x bi , y bi They are respectively phase B, number 1 i The projection of each slot phasor in the x-axis and y-axis directions; x ci , y ci The C phase number i The projection of each slot phasor onto the x-axis and y-axis.

[0032] Then, the vector group H With vector group R =- H Together they constitute 2 Q The matrix of slot phasors P =[ H , R Take a set of positive integers.l 1, l 2, l 3,…, l i ,…, l (Q / 3+i) ,…, l (2Q / 3+i) ,… l 2Q , construction makes and As equal as possible in the composition vector Its expression is: (11) Where: a set of positive integers l 1, l 2, l 3,…, l i ,…, l (Q / 3+i) ,…, l (2Q / 3+i) ,…, l 2Q It can determine the number of winding layers of the motor, a positive integer. l 1, l 2, l 3,…, l i ,…, l (Q / 3+i) ,…, l (2Q / 3+i) ,…, l 2Q In essence, it is 2 Q The number of coil turns increased or decreased for each slot conductor is obtained in this invention by optimization using the existing known technology "genetic algorithm with elitist strategy", see reference [Zheng Qiang. Research and application of non-dominated sorting genetic algorithm with elitist strategy, Control Theory and Control Engineering, Master's thesis of Zhejiang University, 2006]; N c It is half the number of conductors per slot in the initial scheme.

[0033] Therefore, according to equation (11), the newly generated B-phase fundamental magnetomotive force deviation vector can be derived. for: (12) Right now: (13) Furthermore, substituting equation (13) into equation (9), and using a "genetic algorithm with an elite strategy" to determine a set of positive integers that makes equation (9) closest to 0. l 1,l 2, l 3,…, l i ,…, l (Q / 3+i) ,…, l (2Q / 3+i) ,…, l 2Q Substituting this into equation (11) will generate a composite vector that makes the fundamental magnetomotive force deviation vector as close to zero as possible. .

[0034] Step 3: Using phase A as the fixed phase, and adjusting the distribution of the slot phasors of phases B and C along the stator circumference according to the composite vector, the approximate symmetrical design scheme of the asymmetric winding layout of the three-phase motor is finally determined.

[0035] Based on a set of determined positive integers l 1, l 2, l 3,…, l i ,…, l (Q / 3+i) ,…, l (2Q / 3+i) ,…, l 2Q Adjust the distribution of the B-phase slot phasor along the stator circumference. Simultaneously, based on the winding layout design principle of symmetry between the fundamental magnetomotive forces of phases B and C and the fundamental magnetomotive force of phase A, and according to the adjustment of the number of turns of each coil in phase B in step 2, the slot phasor number X to be adjusted in phase C can be deduced. ci The integer solution is calculated as follows: (14) In the formula: i For the adjusted B phase number i The sequence number of each slot phase quantity; α 1 is b 1. Initial phase angle in space; p It is an extreme logarithm.

[0036] Since the slot phasors in the same spatial position in the unit motor have the same magnitude and phase, it is only necessary to adjust the distribution of the C-phase slot phasors along the stator circumference according to one integer solution of equation (14) to make... and The difference vector should be as close to 0 as possible, that is... It tends to be 0.

[0037] Therefore, by adjusting the distribution of the B and C phase phasors along the stator circumference, an approximate symmetrical design scheme for the asymmetric winding layout can be finally determined.

[0038] Example This embodiment takes the approximate symmetrical design of the winding layout of a 21-slot, 18-pole three-phase asymmetrical winding motor as an example. The specific implementation process is as follows: The fundamental magnetomotive forces generated by the three-phase symmetrical windings A', B', and C' are spatially separated by 120° electrical degrees, with phase B' lagging behind phase A' by 120° electrical degrees, and phase C' lagging behind phase B' by 120° electrical degrees. When operating symmetrically, the three-phase currents are also symmetrical, i.e., their amplitudes are equal, but they differ in time by 120° electrical degrees. Figure 1 As shown in the figure, ∠A'OB'=∠B'OC'=∠C'OA'=120°. For a three-phase asymmetrical winding, since the coils connected by the winding are not completely symmetrical, the phase difference in space between each phase will have a slight deviation from 120° electrical angle. Generally, for ease of discussion, the axis position of the fundamental magnetomotive force of the A-phase winding is set to the horizontal right along the x-axis, and it is ensured that the fundamental magnetomotive forces of the B and C phases are symmetrical about the fundamental magnetomotive force of the A-phase, that is, the amplitudes of the fundamental magnetomotive forces of the B and C phases are the same, and ∠AOC=∠AOB≠120°.

[0039] Figure 2 and Figure 3 The initial schemes for a 21-slot, 18-pole three-phase asymmetrical winding motor are shown in the diagrams, including the star-shaped slot electromotive force structure and the winding layout structure. Figure 2 middle a i , b i and c i They are the third of the three phases A, B, and C respectively. i For each slot phasor, the slot electromotive force star diagram of this initial scheme can be obtained through the winding design method provided by the patent technology with authorization announcement number CN116707195B.

[0040] The slot phasors corresponding to the upper side slot conductors of the A, B, and C phases of a 21-slot, 18-pole three-phase asymmetrical winding motor are used to construct a vector group containing 21 two-dimensional column vectors. H The matrix formed by them is: (15) In the formula: a i =[ x ai , y ai ] T , b i =[ x bi , y bi ] T andc i =[ x ci , y ci ] T The first of phases A, B, and C respectively i One slot phasor, x ai , y ai Phase A, number 1 i The projection of each slot phasor in the x-axis and y-axis directions; x bi , y bi They are respectively phase B, number 1 i The projection of each slot phasor in the x-axis and y-axis directions; x ci , y ci The C phase number i The projection of each slot phasor onto the x-axis and y-axis.

[0041] vector group H With vector group R =- H Together they form a matrix containing 42 slot phasors. P =[ H , R Take a set of positive integers. l 1, l 2, l 3,…, l i ,…, l (7+i) ,…, l (14+i) ,…, l 42 , construction makes and As equal as possible in the composition vector Its expression is: (16) Where: a set of positive integers l 1, l 2, l 3,…, l i ,…, l (7+i) ,…, l (14+i) ,…, l 42 The number of winding layers in the motor can be determined, and it is a positive integer. l 1, l2, l 3,…, l i ,…, l (7+i) ,…, l (14+i) ,…, l 42 In essence, it refers to the number of coil turns increased or decreased by 42 slot conductors, which in this embodiment is obtained by optimization using the existing well-known technology of "genetic algorithm with elite strategy"; N c In this embodiment, the number of conductors per slot is half of the number in the initial scheme. N c =10.

[0042] Further, based on equation (16), the newly generated B-phase fundamental magnetomotive force deviation vector is derived. for: (17) Right now: (18) Substituting equation (18) into equation (9) and using a genetic algorithm with an elite strategy, we can finally determine a set of positive integers that makes equation (9) closest to 0. l 1, l 2, l 3,…, l i ,…, l (7+i) ,…, l (14+i) ,…, l 42 Take values, except l 26 =1、 l 36 =1、 l 40 Except for 1, all other positive integers are 0.

[0043] Will l 26 =1、 l 36 =1、 l 40 Substituting 1 into equation (16) will generate the vector that deviates the fundamental magnetomotive force. The composite vector that is as close to zero as possible for: (19) Therefore, based on the above-mentioned composite vector Adjust the distribution of the B-phase slot phasor along the stator circumference. Furthermore, according to equation (14), the vector causing the fundamental magnetomotive force deviation can be determined. The composite vector that is as close to zero as possible for: (20) In the formula: l 26 =1, l 29 =1, l 33 =1.

[0044] According to equations (19) and (20), the distribution of B and C phase slot phasors along the stator circumference is adjusted. Figure 4 The figure shows a winding layout structure for a 21-slot, 18-pole three-phase motor with good symmetry designed using this invention. N P This refers to the number of coil turns that need to be adjusted. Figure 2 In comparison, the winding layout design method of the present invention can effectively reduce the unbalance angle of the three-phase asymmetrical winding and effectively realize the approximate symmetrical design of the asymmetrical winding layout of the three-phase motor.

[0045] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. Those skilled in the art can readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. An approximate symmetry design method suitable for asymmetric winding layouts of motors, characterized in that, Includes the following steps: (1) Introduce the fundamental magnetomotive force deviation vector to construct an approximate symmetry design criterion for the asymmetric winding layout of a three-phase motor; (2) Based on the design principle of approximate symmetry of the asymmetric winding layout of the three-phase motor, a composite vector is generated that makes the fundamental magnetomotive force deviation vector as close to zero as possible; (3) Using phase A as the fixed phase, and adjusting the distribution of the slot phasors of phase B and phase C along the stator circumference according to the composite vector, the approximate symmetrical design scheme of the asymmetric winding layout of the three-phase motor is finally determined.

2. The approximate symmetry design method for asymmetric winding layouts of motors according to claim 1, characterized in that: The fundamental magnetomotive force deviation vector is generated by the fundamental composite magnetomotive force vector of the three-phase symmetrical winding and the three-phase asymmetrical winding. The fundamental magnetomotive force deviation vector of phase A... =0, B-phase fundamental magnetomotive force deviation vector = - C-phase fundamental magnetomotive force deviation vector = - ,in The B-phase fundamental wave composite magnetomotive force vector of the three-phase symmetrical winding. The B-phase fundamental wave composite magnetomotive force vector of the three-phase asymmetrical winding. The C-phase fundamental wave composite magnetomotive force vector of the three-phase symmetrical winding. It is the composite magnetomotive force vector of the C-phase fundamental wave of the three-phase asymmetrical winding.

3. The approximate symmetry design method for asymmetric winding layouts of motors according to claim 2, characterized in that, The expression for the design criterion of approximate symmetry of the asymmetric winding layout of the three-phase motor in step (1) is as follows: ; ， ; in: F ΔΦ The fundamental magnetomotive force deviation vector of phase B amplitude, θ Δ The fundamental magnetomotive force deviation vector of phase B The initial phase angle in space, f D The effective values ​​of the major and minor axes of the elliptical trajectory of the fundamental synthesized magnetomotive force generated by winding asymmetry are given. F + Let be the amplitude of the counterclockwise rotating component in the fundamental rotating magnetomotive force generated by winding asymmetry. F - It represents the amplitude of the clockwise rotation component in the fundamental rotating magnetomotive force generated by winding asymmetry.

4. The approximate symmetry design method for asymmetric winding layouts of motors according to claim 2, characterized in that, The expression for the synthesized vector in step (2) is as follows: ; in: In order to make and The composite vectors that are as equal as possible, (Δ x ΔB'B , Δ y ΔB'B ) is the composite vector coordinates a i =[ x ai , y ai ] T , b i =[ x bi , y bi ] T and c i =[ x ci , y ci ] T The first of phases A, B, and C respectively i One slot phasor, x ai and y ai Phase A, number 1 i The projected coordinates of each slot phasor in the x-axis and y-axis directions. x bi and y bi They are respectively phase B, number 1 i The projected coordinates of each slot phasor in the x-axis and y-axis directions. x ci and y ci The C phase number i The projected coordinates of each slot phasor in the x-axis and y-axis directions. i =1,2,…, Q / 3, Q This refers to the number of stator slots of the motor. N c It is half the number of conductors per slot in the initial scheme; l 1, l 2, l 3,…, l 2Q A set of positive integers is used to determine the number of winding layers in the motor, which essentially corresponds to 2. Q The number of coil turns increased or decreased for each slot conductor is obtained by optimization using a genetic algorithm with an elite strategy, based on the design principle of approximate symmetry of the asymmetric winding layout of a three-phase motor.

5. The approximate symmetry design method for asymmetric winding layouts of motors according to claim 4, characterized in that, Based on the design principle of approximate symmetry of asymmetrical winding layout of three-phase motor, the B-phase fundamental magnetomotive force deviation vector The expression is as follows: ; in: θ The electrical angle is along the inner circumferential surface of the stator. ω Angular frequency, t Indicates time, Δ x bb' = x b - x b' Δ y bb' = y b - y b' , x b and y b These are the composite magnetomotive force vectors of the B-phase fundamental wave. Projected coordinate values ​​in the x-axis and y-axis directions. x b' and y b' These are the composite magnetomotive force vectors of the B-phase fundamental wave. Projected coordinate values ​​in the x-axis and y-axis directions. F ΔΦ The fundamental magnetomotive force deviation vector of phase B amplitude, θ Δ The fundamental magnetomotive force deviation vector of phase B The initial phase angle in space.

6. The approximate symmetry design method for asymmetric winding layouts of motors according to claim 5, characterized in that, The amplitude F ΔΦ and initial phase angle θ Δ The expression is as follows: 。 7. The approximate symmetry design method for asymmetric winding layouts of motors according to claim 4, characterized in that: In step (3), a set of positive integers determined by the genetic algorithm is used. l 1, l 2, l 3,…, l 2Q Adjust the distribution of the B-phase slot phasor along the stator circumference; then determine the slot phasor number X to be adjusted in phase C using the following formula. ci This allows for the adjustment of the distribution of the corresponding slot phase quantity along the stator circumference to make... and The difference should be as close to 0 as possible, that is, the C-phase fundamental magnetomotive force deviation vector. It tends to be 0; ; in: α 1 represents the tank phase quantity b 1. Initial phase angle in space, p Let be the number of pole pairs of the motor, and mod[ ] represents the modulo operation.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: The processor is used to execute the computer program to implement the approximate symmetry design method for asymmetric winding layouts of motors as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the approximate symmetry design method for asymmetric winding layouts of motors as described in any one of claims 1 to 7.

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