A method and system for determining parameters of unequal element coils of a permanent magnet motor

Abstract

The present invention discloses a method and system for determining parameters of unequal element coils of a permanent magnet motor. The method calculates the no-load back electromotive force based on the winding coefficient amplitude and initial phase corresponding to the winding harmonic v of the corresponding pole under different numbers, spans and turns of the unequal element coils; constructs an objective function of the motor fundamental no-load back electromotive force amplitude with respect to the amplitude and phase of the winding coefficient, and converts it into an objective function with respect to the structural parameters of the unequal element coils; takes the maximum fundamental no-load back electromotive force amplitude as the design goal, and obtains the unequal element coil structural parameters that maximize the objective function; there is a clear correspondence between the designed unequal element coils and the actual winding structure; the obtained winding structure and the slot structure in which it is located are integrated with a modulation unit to obtain the optimal stator specific structure. The method provided by the present invention can improve the fundamental back electromotive force amplitude, so that the motor obtains a stronger torque generation capability, thereby improving the torque density of the motor.

Description

Technical Field

[0001] The present invention belongs to the field of permanent magnet motors, and more specifically, relates to a method and system for determining parameters of unequal element coils of a permanent magnet motor. Background Art

[0002] As a widely used and critical basic component, motors play a key role in improving the overall level of the equipment manufacturing industry. High torque density has always been a primary goal of motor development, significantly reducing motor size and cost, while also improving response speed. At the same time, the rapid development of the manufacturing industry has also placed higher demands on motor torque density.

[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 have a similar structure to conventional permanent magnet motors, but based on the principle of magnetic field modulation, they utilize two working magnetic fields to convert electromechanical energy to generate torque, thereby achieving a higher torque density. However, when designing conventional permanent magnet motors and vernier permanent magnet motors, the motors often adopt an open-slot stator structure, with the windings wound in the stator slots. This results in strong spatial coupling between the stator and windings. The windings must be designed based on pole-slot matching and according to the traditional "equal-element winding" phase-splitting method. This results in the permanent magnet motor's magnetic field harmonics failing to interlink with the windings to generate the maximum fundamental back EMF, thus failing to achieve the theoretical maximum torque output. Summary of the Invention

[0004] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a method and system for determining the parameters of unequal element coils of a permanent magnet motor, thereby solving the technical problems of the existing permanent magnet motor winding structure design being rigid, the air gap magnetic field harmonic utilization rate being low, and the difficulty in achieving motor topology innovation and torque density improvement.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a method for determining parameters of unequal element coils of a permanent magnet motor is provided, wherein adjacent stator teeth of the permanent magnet motor have different numbers of turns and different spans of coils, the method comprising:

[0006] S1, according to the number N e , span is θ yi , the number of turns is N ci Under the configuration of unequal element coil parameters, the winding coefficient amplitude k corresponding to the winding harmonic v pair wv and the initial phase θ sv , determine the fundamental back EMF amplitude of the permanent magnet motor;

[0007] S2. Under preset constraint conditions, by maximizing the fundamental back electromotive force amplitude, an optimal configuration of the unequal element coil parameters of the permanent magnet motor is obtained. Among them, the preset constraint conditions include:

[0008] Winding symmetry constraint: N e = 3n, n = 1, 2,..., n is the number of types of unequal element coils in one phase belt, P r = kGCD(N e , P a ), when P a and P r have different parities, N e / GCD(N e , P a ) is odd; P r is the number of pole pairs of the permanent magnet array, P a is the minimum number of pole pairs in the air-gap magnetic field harmonics, k is a positive integer;

[0009] Slot opening coefficient constraint: θ so is the slot opening coefficient;

[0010] Initial phase constraint: kπ < P r θ yi / 2 < (k + 1)π and kπ < P a θ yi / 2 < (k + 1)π, θ yi is the span of the i-th unequal element coil c i in one phase belt, N ci is the number of turns of the i-th unequal element coil c i in one phase belt; i = 1, 2,..., n.

[0011] According to the second aspect of the present invention, a permanent magnet motor is provided, including a stator wound with windings, a permanent magnet array, a rotor, a modulation unit, and a rotating shaft. Unequal element coils are wound on each stator tooth portion; there is an air gap formed between the rotor and the stator, a permanent magnet array is embedded on the rotor near the air-gap surface, and a modulation unit is arranged on the stator near the air-gap surface. The unequal element coil parameters of the permanent magnet motor are determined by the method described in the first aspect.

[0012] According to the third aspect of the present invention, a system for determining the unequal element coil parameters of a permanent magnet motor is provided, including: a computer-readable storage medium and a processor;

[0013] The computer-readable storage medium is used to store executable instructions;

[0014] The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the method described in the first aspect.

[0015] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0016] 1. The method for determining the parameters of the unequal-element coils of a permanent magnet motor provided by the present invention combines parameters such as the phase and amplitude of the air gap working magnetic field to construct an objective function of the fundamental back-electromotive force with respect to the winding coefficient; then, by establishing a function of the winding coefficient with respect to the winding structure, that is, the number of unequal-element coils, the span, and the number of turns, the winding structure and the corresponding stator structure that maximize the fundamental back-electromotive force amplitude are finally solved. This is expected to solve the problems in the prior art of the permanent magnet motor winding structure design being rigid, the air gap magnetic field harmonic utilization being low, and the difficulty in achieving motor topology innovation and torque density improvement.

[0017] 2. The method for determining the parameters of the unequal-element coils of a permanent magnet motor provided by the present invention combines the analysis of the harmonic characteristics of the air gap magnetic field to generate the winding harmonics required for the maximum fundamental back-electromotive force of the motor, and reversely deduces the specific winding structure, and proposes a guiding concept and model of unequal-element coils. The winding structure corresponding to the maximum fundamental back-electromotive force can be directly calculated through analytical methods, thereby giving full play to the electromechanical energy conversion capabilities of the permanent magnet and winding.

[0018] 3. The motor constructed using the method for determining unequal-element coil parameters for a permanent magnet motor provided by the present invention has an irregularly and unevenly distributed modulation unit structure. When interacting with the permanent magnet array, the modulation unit can generate multiple air gap magnetic fields that participate in electromechanical energy conversion. By analyzing the operating harmonic components of the constructed winding, the number of basic units of the modulation unit is determined. With the basic modulation unit as the optimization object, its structural parameters are further optimized, thereby generating an air gap magnetic field corresponding to the number of harmonic pole pairs of the winding and participating in the generation of the fundamental back EMF, thereby further increasing the amplitude of the fundamental back EMF, enabling the motor to obtain stronger torque generation capability and further improving the torque density of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Flowchart of a method for constructing a permanent magnet motor based on unequal element coils according to an embodiment of the present invention;

[0020] Figure 2 This is one of the overall structural diagrams of the permanent magnet motor provided by an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of one configuration of unequal element coils provided in an embodiment of the present invention;

[0022] Figure 4 A second schematic diagram of the unequal element coil configuration method provided by an embodiment of the present invention;

[0023] Figure 5The second schematic diagram of the overall structure of the permanent magnet motor provided by the embodiment of the present invention;

[0024] Figure 6 Schematic diagram of a modulation unit and a basic modulation unit in an embodiment of the present invention;

[0025] Figure 7 A schematic diagram of the overall structure of the stator in the permanent magnet motor provided in an embodiment of the present invention;

[0026] Figure 8 Schematic diagram of the overall structure of the rotor in the permanent magnet motor provided in an embodiment of the present invention;

[0027] Figure 9 This is the third overall structural diagram of the permanent magnet motor provided in an embodiment of the present invention.

[0028] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0029] 1- Modulation unit, 2- Winding, 3- Unequal element coil, 4- Stator, 5- Rotor, 6- Permanent magnet array, 7- Rotating shaft, 8- Basic modulation unit. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is 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 for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0031] The embodiment of the present invention provides a method for determining parameters of unequal element coils of a permanent magnet motor, wherein the number of turns and the span of the coils of adjacent stator teeth of the permanent magnet motor are different, such as Figure 1 As shown, the method includes:

[0032] S1, according to the number N e , span is θ yi , the number of turns is N ci Under the unequal element coil parameter configuration, the winding coefficient amplitude k corresponding to the winding harmonic v pole (i.e. the vth winding harmonic) wv and the initial phase θ sv , determine the no-load back EMF amplitude of the permanent magnet motor.

[0033] S2, obtaining an optimal configuration of unequal element coil parameters of the permanent magnet motor by maximizing the no-load back EMF under preset constraints; wherein the preset constraints include:

[0034] Winding symmetry constraint: N e= 3n, where n = 1, 2,..., and n is the number of types of unequal element coils in a phase belt, P r = kGCD(N e , P a ), when P a and P r have different parities, N e / GCD(N e , P a ) is odd; P r is the number of pole pairs of the permanent magnet array, P a is the minimum number of pole pairs in the air-gap magnetic field harmonics, and k is a positive integer;

[0035] Slot opening coefficient constraint: θ so is the slot opening coefficient;

[0036] Initial phase constraint: kπ < P r θ yi / 2 < (k + 1)π and kπ < P a θ yi / 2 < (k + 1)π, θ yi is the span of the i-th type of unequal element coil in a phase belt, N ci is the number of turns of the i-th type of unequal element coil c i in a phase belt; i = 1, 2,..., n.

[0037] Specifically, according to the interaction between the permanent magnet and the modulation unit (as shown in Figure 1 , 6 ), the modulation unit includes multiple modulation teeth, and each modulation tooth is integrally manufactured with the corresponding stator tooth), calculate the amplitudes B th and initial phases θ v and rotation directions sgn(v) (defined as in Equation (1)) of the various air-gap magnetic field harmonics v v ]](i.e., the v-th air-gap magnetic field harmonic), and calculate the objective function of the fundamental back electromotive force e1 with respect to the winding coefficient amplitudes k wv [[ID=V8]]and initial phases θ<0000'054>, as shown in Equation (2-1).

[0038] Furthermore, transform the objective function (2-1) into an objective function of E1 with respect to the phase winding structure parameters (i.e., unequal element coil parameters). That is, according to the number N e of unequal element coils, the span θ y , and the number of turns N c calculate the winding coefficients of the various harmonics under a feasible winding structure; and transform the objective function shown in Equation (2-1) into an objective function of the fundamental back electromotive force amplitude E1 with respect to the unequal element coil structure parameters, as shown in Equation (2-`2).

[0039] Among them, the pole pair number is defined as 1 as the fundamental wave of the winding, and the order of the air gap magnetic field is equal to the pole pair number, then the winding harmonic v th Corresponding to v pole pairs.

[0040]

[0041] The positive rotation direction is counterclockwise, sgn = +1; the negative rotation direction is clockwise, sgn = -1.

[0042]

[0043] Among them, D g is the diameter corresponding to the motor air gap; L is the effective shaft length of the motor; N s is the number of series turns of the phase winding; Ω is the mechanical angular velocity of the rotor; P r is the number of pole pairs of the permanent magnet array, P m is the number of modulation teeth in the modulation unit, that is, the number of fundamental wave pole pairs of air gap magnetic permeability; t is the time; v is the number of air gap working magnetic flux density.

[0044]

[0045] It should be explained that, ignoring the motor saturation, the average torque T of the motor and the fundamental back EMF amplitude E1 satisfy the relationship (3), so E1 can be used to reflect the magnitude of the average torque.

[0046]

[0047] Among them, I m Indicates the current amplitude passing through the phase winding.

[0048] like Figure 2 As shown, the permanent magnet motor includes a stator 4 wound with a winding 2, a permanent magnet array 6, a rotor 5, a modulation unit 1, and a rotating shaft 7. A unequal-element coil 3 is wound around each stator tooth. Specifically, for example, the stator, rotor, and rotating shaft are coaxially arranged from the outside to the inside, or the rotor, stator, and rotating shaft are coaxially arranged from the outside to the inside. An air gap is formed between the rotor and the stator. The permanent magnet array is embedded on the rotor surface near the air gap, and the modulation unit is provided on the stator surface near the air gap.

[0049] In this embodiment, Figure 6-9 The stator, rotor, and rotating shaft shown in the figure are coaxially arranged from the outside to the inside, the permanent magnet array is embedded in the rotor near the air gap surface, and the modulation unit (i.e., modulation tooth) is provided on the stator near the air gap surface. The specific operation process of the permanent magnet motor construction method based on unequal element coils provided by the present invention is explained.

[0050] The winding is composed of unequal element coils connected in series. On the one hand, the unequal element coils are a design tool as an intermediate medium and do not really exist; on the other hand, the span angle θ of the unequal element coils y and number of turns N c Different, at the same time, the number of unequal element coils N e It can also be designed arbitrarily. Therefore, different N e ,θ y and N c The phase windings composed of coils of unequal elements will have different structures.

[0051] The number of unequal element coils N e , span θ yi and number of turns N ci The design needs to be carried out according to the preset constraints.

[0052] First, the number of unequal element coils N e , that is, the number of stator main teeth must be an integer multiple of the number of winding phases (here is three phases). N e =3n,n=1,2....

[0053] Second, N e and the minimum number of pole pairs P in the air gap magnetic field harmonics a and rotor pole pair number P r The relationship needs to satisfy P r =kGCD(N e ,P a ), GCD means the least common multiple. In addition, when P a and P r When the parity is different, the following conditions must be met: N e / GCD(N e ,P a )=odd number.

[0054] The above rules are the conditions for the symmetry of the three-phase windings.

[0055] Third, the slot coefficient constraint: the stator slot size θ for embedding the winding so The influence of the winding coefficient is reflected in the notch coefficient k sv The larger the harmonic pole pair number v is, the smaller the slot coefficient is. In order to ensure that the winding coefficient is not affected by the stator slot, the design θ so satisfy

[0056] Fourth, initial phase constraint: ensure P a times and P r The winding coefficients of the second winding have the same phase, so kπ<P r θ yi-π / 2 < (k + 1)π and kπ < P a θ yi -π / 2 < (k + 1)π, so that the fundamental back electromotive force phases induced by the two main working magnetic field harmonics can be ensured to be the same.

[0057] In order to form a three-phase symmetrical winding, there are n types of composition methods for unequal element coils (n is the number of types of unequal element coils in one phase belt). It can simultaneously make the axis of a certain phase coincide with the defined zero axis, obtain a larger winding coefficient, and there are two series connection methods in each type. Assume that the axis of coil c1 coincides with the zero axis. Among the n types of composition methods, one type is the series connection of all coils in one phase belt, and the other n - 1 types are the series connection of unequal element coils under different phase belts. More specifically, these n - 1 types of series connection methods include:

[0058] 1) The series connection of n unequal element coils in one phase belt and all coils other than the coils of the same type as the No. 1 coil in the adjacent two phase belts;

[0059] 2) It is composed of the series connection of n unequal element coils in one phase belt and n - 2 unequal element coils in an adjacent phase belt. These n - 2 coils do not include the coils of the same type as the No. 1 coil and the coils whose structural parameters are not independent variables (among the n types of unequal element coils, only the structural parameters of n - 1 types of unequal element coils are independent variables, and the structural parameters of the remaining 1 type of unequal element coil are dependent variables).

[0060] The two series connection methods in each type are mainly distinguished according to the number of turns of the unequal element coils, and the specific expression is shown in (4).

[0061]

[0062] The first one represents the direct series connection of all unequal element coils, so the sum of their turns is the total series connection turns of the phase winding. The second one is more complex and involves the specific value of N ci Specifically, the specific structure of the phase winding is usually the series connection of several coils with different spans and different turns. Figure 2 Figures respectively show the specific structures of two possible phase windings when n = 2.

[0063] Even if the structures of the phase windings are different, their winding harmonics can still be obtained by analyzing the vector sum of the winding harmonics of each type of unequal element coil, without involving the specific series connection method. Therefore, under the n types of composition methods of unequal element coils in one phase belt, the winding coefficient k th of the v winding harmonics wv and the initial phase θ sv can be determined by the general formula (5).

[0064]

[0065] Where M represents the number of unequal element coils in series (M is not greater than 2n-1), Δθ i Indicates unequal element coil c i The angle between the axis of and the 0 axis is determined by formula (6).

[0066]

[0067] Among them, k wv,ci Indicates unequal element coil c i The winding function can be calculated by formula (7).

[0068]

[0069] Among them, k yv represents the pitch coefficient, k sv Indicates the notch coefficient.

[0070] The number of rotor permanent magnet pole pairs is set to single harmonic P r =10, the number of coils of different components is N e =6(n=2) as an example. Figure 3-4 As shown, there are two types of unequal element coils at this time, defined as c1 and c2 respectively. The central axis of the unequal element coil c1 is used as the initial position, and the angle between the axes is a fixed value of 60°. The span angle θ y1 and θ y2 The sum is also a constant value of 120°. According to the above rule 4, θ can be designed y1 By changing between [0°, 36°], [72°, 108°] and [144°, 180°], then θ y2 Changes followed.

[0071] In this example, there are two types of unequal element coil configurations, i.e., n=2, and each type has two series connection methods. In this embodiment, the first type is the series connection of c1 and c2, and the second type is the series connection of c1, c2, and c2″. In this embodiment, v th Winding factor k of winding harmonics wv , initial phase θ sv It can be determined by the general formula (5).

[0072] P a th and P r th Taking this as an example, equation (6) can be expanded into equation (8):

[0073]

[0074]

[0075] It can be seen that the winding coefficient amplitude and initial phase at this time are about the unequal coil span θ yi ,Number of turns N ci Therefore, by substituting the winding coefficient function of the winding structure parameters into (2-2), the fundamental back EMF amplitude E1 is transformed into a function of θ yi and N ci The objective function.

[0076] Furthermore, according to the objective function shown in formula (2-2), the maximum E1 is solved to obtain the structural parameters of the unequal element coil at this time, and further obtain the specific characteristics of the corresponding winding and the tooth slot structure in which it is located.

[0077] Specifically, for θ within the range of yi And N with different values ​​in different types and categories ci , solve E1. Find the structural parameters of the unequal element coil corresponding to the maximum E1 and obtain the corresponding winding specific structure.

[0078] In this embodiment, since the air gap is mainly P a th and P r th Working magnetic field harmonics, and define P r th The initial phase θ of the air gap magnetic field Pr is -90°, according to magnetic field modulation theory, P a th The initial phase of the magnetic field is also -90°. Combining (2), (5) and (6), the maximum value of E1 and the structural parameters of the unequal element coil at this time can be directly obtained analytically: θ y1 =79°,N c1 =N c2 =400 (Class 2, Type 2). Therefore, the specific winding structure and the slot structure in which it is located are as follows: Figure 2-5 shown.

[0079] The above steps are carried out under the condition that the number of unequal element coils is determined, and are applicable to any number of unequal element coils.

[0080] The method provided by the present invention takes into account that the permanent magnet excitation magnetomotive force generates a series of magnetic field harmonics of pole pairs in the air gap through the modulation unit, and the amplitude, initial phase and rotation direction are known, which are uniformly represented as B v ,θ v and sgn(v). According to the different number of coils of different components N e , span θ yi and the number of turns N ciIn the case of the corresponding winding harmonic v, the winding coefficient amplitude k corresponding to the pole wv and the initial phase θ sv Calculate the no-load back EMF amplitude E1; construct an objective function of the motor fundamental wave no-load back EMF E1 with respect to the amplitude and phase of the winding coefficient, and further transform it into an objective function of E1 with respect to the structural parameters of the unequal element coil; taking the maximum E1 as the design goal, the structural parameters of the unequal element coil that maximizes the objective function can be obtained; there is a clear correspondence between the above-designed unequal element coil and the actual winding structure; the obtained winding structure and the slot structure in which it is located are integrated with the modulation unit to obtain the optimal stator specific structure.

[0081] The above air gap working magnetic field B v The number is one or more, forming a corresponding single harmonic working magnetic field or a multi-harmonic working magnetic field.

[0082] An embodiment of the present invention provides a permanent magnet motor, comprising a stator wound with a winding, a permanent magnet array, a rotor, a modulation unit, and a rotating shaft, wherein an unequal element coil is wound around each stator tooth; an air gap is formed between the rotor and the stator, a permanent magnet array is embedded in a surface of the rotor near the air gap, and a modulation unit is provided on a surface of the stator near the air gap, wherein the parameters of the unequal element coil of the permanent magnet motor are determined using the method described in any of the above embodiments.

[0083] Preferably, the stator, rotor and rotating shaft are coaxially sleeved in sequence from outside to inside;

[0084] Alternatively, the rotor, the stator and the rotating shaft are coaxially sleeved in sequence from outside to inside.

[0085] like Figure 7-9 As shown, the permanent magnet motor includes a coaxially arranged rotor 5, a stator 4, and a rotating shaft 7. A modulation unit 1 is provided on the side of the stator 4 opposite the rotor 5. The permanent magnet motor also includes a permanent magnet array 6, which is arranged opposite the modulation unit 1 with an air gap formed therebetween. The permanent magnet array 6 is magnetized radially, with adjacent permanent magnets magnetized in opposite directions. The permanent magnet motor also includes a winding 2, which is wound around the stator teeth. The stator is composed of two alternating groups of stator teeth of different widths. The parameters of the unequal element coils of the permanent magnet motor are determined using the method described in any of the above embodiments.

[0086] An embodiment of the present invention provides a system for determining parameters of unequal element coils of a permanent magnet motor, comprising: a computer-readable storage medium and a processor;

[0087] The computer-readable storage medium is used to store executable instructions;

[0088] The processor is configured to read the executable instructions stored in the computer-readable storage medium and execute the method described in any one of the above embodiments.

[0089] It will be easily understood by those skilled in the art 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 in the scope of protection of the present invention.

Claims

1. A method for determining the parameters of unequal element coils of a permanent magnet motor, characterized in that: The number of turns and the span of the coils of adjacent stator teeth of the permanent magnet motor are different, and the method includes: S1, according to the number N e , span is θ yi , the number of turns is N ci Under the configuration of unequal element coil parameters, the winding coefficient amplitude k corresponding to the winding harmonic v pair wv and the initial phase θ sv , determine the fundamental back EMF amplitude of the permanent magnet motor; S2, obtaining an optimal configuration of unequal element coil parameters of the permanent magnet motor by maximizing the fundamental back EMF amplitude under preset constraints; wherein the preset constraints include: Winding symmetry constraint: N e =3n, n=1,2..., n is the number of types of unequal element coils in a phase band, P r =kGCD(N e ,P a ), when P a and P r With different parity, N e / GCD(N e ,P a ) is an odd number; P r is the number of pole pairs of the permanent magnet array, P a is the minimum pole pair number in the air gap magnetic field harmonics, k is a positive integer; Notch factor constraint: θ so is the notch coefficient; Initial phase constraint: kπ < P r θ yi / 2 < (k + 1)π and kπ < P a θ yi / 2 < (k + 1)π, θ yi is the span of the i-th unequal element coil c in a phase belt i N ci is the number of turns of the i-th unequal element coil c in a phase belt i ; i = 1, 2, …, n 2. The method according to claim 1, wherein The fundamental back electromotive force amplitude of the permanent magnet motor in, D g is the diameter corresponding to the motor air gap; L is the effective shaft length of the motor; N s is the number of series turns of the phase winding; Ω is the mechanical angular velocity of the rotor; P m is the number of fundamental wave pole pairs of the air gap permeability of the motor; t is the time; v is the number of air gap working magnetic flux density; M is the number of unequal element coils in series, M≤2n-1; j is the number of unequal element coils, j=1,2,…,N e ,,k wv,ci is the i-th unequal element coil c in a phase band i The winding function, 3. The method according to claim 2, wherein Unequal element coil c i The winding function k wv,ci =k yv, ci k sv,ci ,in, 4. The method according to claim 2, wherein When n=2, 5. The method according to claim 2, wherein For n types of unequal-element coils, there are two ways of connecting them in series for each type; In one of the series connection modes, In another series connection mode, N c1 =N s ,N ci(i＝2,3..n) ∈(0,N s ]; Among them, N s is the total number of series turns per phase.

6. A permanent magnet motor comprising a stator wound with windings, a permanent magnet array, a rotor, a modulation unit, and a rotating shaft, wherein a coil of unequal elements is wound around each stator tooth; an air gap is formed between the rotor and the stator, the permanent magnet array is embedded in the rotor surface near the air gap, and the modulation unit is provided on the stator surface near the air gap, characterized in that: The unequal element coil parameters of the permanent magnet motor are determined by the method according to any one of claims 1 to 5.

7. The permanent magnet motor according to claim 6, characterized in that: The stator, rotor and rotating shaft are coaxially sleeved in sequence from outside to inside; Alternatively, the rotor, the stator and the rotating shaft are coaxially sleeved in sequence from outside to inside.

8. A system for determining parameters of unequal element coils of a permanent magnet motor, characterized in that: include: Computer-readable storage media and processor; The computer-readable storage medium is used to store executable instructions; The processor is configured to read the executable instructions stored in the computer-readable storage medium and execute the method according to any one of claims 1 to 5.

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