A high torque density differential modulation vernier permanent magnet motor

Abstract

The present invention relates to a differential modulation vernier permanent magnet motor with high torque density, and its structure includes two parts: an outer stator and an inner rotor. The outer stator is composed of a stator yoke 1, stator teeth and an armature winding 4 from the outside to the inside. The stator yoke 1 is a metal cylinder, and a "V"-shaped stator tooth is connected inside. The armature winding 4 is between adjacent stator teeth. There is an air gap between the stator teeth and the outer surface of the inner rotor. The inner rotor is composed of a rotor permanent magnet 5, a rotor core 6, and a rotor shaft 7 from the outside to the inside. The rotor permanent magnet 5 and the rotor core 6 are cylindrical, and the rotor shaft 7 is cylindrical. The three are tightly connected and can rotate synchronously. Through the design of the "V-shaped" stator teeth, the tooth top space position of the stator teeth is offset by 180 electrical degrees compared with the conventional tooth top position, which solves the technical problems of low torque density and small pole slot matching selection range of the differential modulation vernier permanent magnet motor, broadens the pole slot matching selection range of the vernier permanent magnet motor, and eliminates the pole slot quantity relationship restriction of the design work.

Description

Technical Field

[0001] The invention relates to the field of permanent magnet motor design, in particular to the design of a differential modulation vernier permanent magnet motor with high torque density. Background Art

[0002] Torque density is an important indicator to measure the performance of permanent magnet motors, but the torque density of conventional differential modulation vernier permanent magnet motors is affected by the design, and torque density becomes its inherent shortcoming. Figure 1 As shown in the figure, the vernier permanent magnet motor consists of an open slot stator, a permanent magnet rotor and an armature winding. The three parts must satisfy the relationship Z1=Z2+p or Z1=Z2-p, where Z1, Z2, and p are the number of stator teeth, the number of rotor pole pairs, and the number of winding pole pairs, respectively. Due to this special relationship, when the rotor rotates one tooth pitch, the magnetic field rotates one pole pitch, that is, a smaller rotor displacement can produce a larger magnetic flux change, and then generate high torque. This phenomenon is called the magnetic gear effect.

[0003] The "differential modulation" vernier permanent magnet motor satisfies the following relationship

[0004] Z1=Z2-p (1)

[0005] The harmonic coupling theory explains the torque generation mechanism of the differential modulation vernier permanent magnet motor. When Z1=Z2-p is satisfied, the armature magnetomotive force contains p-pole harmonics and Z2-p-pole tooth harmonics, and the excitation flux density contains Z2-pole harmonics and Z2-Z1-pole modulation harmonics. Since the above relationship is satisfied, the armature magnetomotive force p-pole harmonics and the excitation flux density Z2-Z1-pole harmonics have the same number of pole pairs and rotate synchronously in the clockwise direction (counterclockwise direction), and the armature magnetomotive force Z1-p-pole harmonics and the excitation flux density Z2-pole harmonics have the same number of pole pairs and rotate synchronously in the counterclockwise direction. The two sets of harmonics are coupled separately to generate two torque components, which are superimposed (cancelled) on each other to generate a net torque.

[0006] The formula corresponding to the torque density of the permanent magnet motor is derived as follows:

[0007] by Figure 2 For example, the permanent magnet magnetomotive force expression of the motor is as follows

[0008]

[0009] In the formula, F PM1 Yes F PM The amplitude of the fundamental component, θ1, θ2, θ m They are stator mechanical angle, rotor mechanical angle, and rotor position. The definitions of each angle are as follows Figure 1 As shown, the position of θ1=0 is in the positive direction of the U-phase winding axis, and the position of θ2=0 is in the center line of the permanent magnet shown in the figure. The magnetization direction of the permanent magnet points to the air gap. m =θ1-θ2.

[0010] The air gap permeance per unit area in the axial direction, referred to as air gap permeance, is expressed as follows:

[0011]

[0012] Where P m is the amplitude of the mth harmonic of the air gap permeability, j is the difference between the span and the pole pitch of the short-pitch coil, and j=0 represents a full-pitch coil.

[0013] The air gap flux density generated by the permanent magnet satisfies equation (4).

[0014] B PM =F PM ·P (4)

[0015] Substituting equations (2) and (3) into equation (4), the expression of the air gap flux density generated by the permanent magnet is as follows (only considering F PM and the main terms of P, n = 1 and m = 0, 1, and ignoring the higher-order magnetic flux harmonic components above the Z2 pole)

[0016]

[0017] The armature winding current i x The expression of (x=U,V,W) is

[0018]

[0019] In the formula, I is i x The effective value of ω is the angular frequency of the armature winding current, α is a random angle, and for the three-phase currents U, V, and W, a=0, 1, 2.

[0020] The expression of the air gap magnetomotive force generated by the armature is as follows

[0021]

[0022] in:

[0023]

[0024]

[0025] k pn =sin(nβπ / 2) (10)

[0026] β=1-(j / 3q) (11)

[0027] Where N is the number of series turns of each phase winding, k dn and k pnis the distribution coefficient and short-distance coefficient of the nth harmonic, and Fc1 is the amplitude of the phase winding magnetomotive force.

[0028] Among the harmonics of the air gap magnetomotive force generated by the armature, the one that can provide the average torque is related to B PM Those harmonics with the same harmonic order. Specifically, the p-th harmonic when n=1 and the Z1+p=Z2-th harmonic when n=Z1 / p+1 in the armature magnetomotive force, together with the p-pole component and the Z2-pole component in the permanent magnet air gap flux density, can generate an average torque. Therefore, the expression of the armature magnetomotive force is simplified as follows.

[0029]

[0030] In general, the following approximation can be made, assuming that all the magnetic field energy is stored in the air gap and the permanent magnet (virtual air gap). The average torque can be calculated based on the virtual displacement method:

[0031]

[0032]

[0033] Where λ is the winding pole pitch, l is the effective length of the core, B and F are the magnetic density and magnetomotive force in the air gap, respectively.

[0034] F C and B PM Substituting the simplified expression of into the above formula, we can get the torque expression

[0035]

[0036] When the armature winding current is set reasonably, the maximum stable torque can be obtained

[0037] ω=-Z2ω m (15)

[0038]

[0039]

[0040] The torque density of the conventional differential modulation vernier permanent magnet motor is derived as follows:

[0041] like Figure 2As shown, the conventional differential modulation vernier permanent magnet motor includes an outer stator and an inner rotor, wherein the outer stator is fixed and is composed of three parts, namely, a stator yoke 1, stator teeth and armature winding 4 from the outside to the inside, wherein the stator yoke 1 is a metal cylinder, which is connected to the stator teeth inside; each stator tooth is composed of a metal strip with a rectangular interface, and the armature winding 4 is distributed between adjacent stator teeth; the inner rotor is composed of a rotor permanent magnet 5, a rotor core 6, and a rotor shaft 7 from the outside to the inside, wherein the rotor permanent magnet 5 and the rotor core 6 are cylindrical, and the rotor shaft 7 is cylindrical, and the three are closely connected in sequence and can rotate synchronously. There is an air gap between the rotor permanent magnet 5 and the stator teeth.

[0042] Figure 3 This is a schematic diagram of the angle definition of an existing differential modulation vernier permanent magnet motor. The stator tooth root 2 includes a first tooth root 21, a second tooth root 22, a third tooth root 23, etc. The stator tooth top 3 includes a first tooth top 31, a second tooth top 32, a third tooth top 33, etc. The winding includes a first coil side 41, a second coil side 42, etc. A polar coordinate system is established with the center of the stator as the origin and the center line of the first tooth root 21 as the θ1 axis. θ1 represents the mechanical angle in the stator coordinate system, ranging from 0 to 2π. The tooth root, tooth top, and coil side are all located on the stator, and the position of their center lines can be described by "θ1 = a certain value". In order to distinguish the three, the position of the center line of the tooth root is represented by the symbol θ 1bk Indicates, b indicates the bottom root, k indicates the kth tooth; the position of the center line of the tooth top is represented by the symbol θ 1tk Indicates, t indicates top; the position of the center line of the coil side is represented by the symbol θ 1ck represents, c represents the top of the coil. The position of the center line of the kth tooth root is θ 1bk , the position of the center line of the kth tooth tip is θ 1tk , the position of the center line of the kth coil side is θ 1ck The center line of the first tooth root 21 and the first tooth top 31 is located at θ1=0, that is, θ 1b1 =θ 1t1 =0. That is, the center line of the second tooth root 22 and the second tooth top 32 is located at θ1=0+2π / Z1, that is, θ 1b2 =θ 1t2 =0+2π / Z1 and so on. The first coil side 41 is located in the groove surrounded by the first tooth root 21, the second tooth root 22, the first tooth top 31 and the second tooth top 32, and its center line is located at θ1=π / Z1, that is, θ 1c1 =π / Z1. The second coil side 42 is located in the groove surrounded by the second tooth root 22, the third tooth root 23, the second tooth top 32, and the third tooth top 33, and its center line is located at θ1=π / Z1+2π / Z1, that is, θ 1c2 =π / Z1+2π / Z1, and so on.

[0043] The armature winding positions of the existing differential modulation vernier permanent magnet motor and the differential modulation vernier permanent magnet motor of the present invention are the same, and the center lines of the coil sides are both located at θ 1ck =π / Z1+k×2π / Z1, so the expression of the armature magnetomotive force is the same, which is formula (12).

[0044] The rotor structures of the existing differential modulation vernier permanent magnet motor and the differential modulation vernier permanent magnet motor of the present invention are the same, so the permanent magnet magnetomotive force expression is the same, both of which are the above formula (2).

[0045] The tooth top center line of the existing differential modulation vernier permanent magnet motor is located at θ 1tk =0+k×2π / Z1, so the air gap permeance waveform is as follows Figure 4 As shown, the expression is formula (18),

[0046] P(θ1)=P0+(-1) j P1cos(Z1θ1) (18)

[0047] The general derivation of motor torque satisfies formula B PM =F PM ·P,

[0048] The torque formula of the existing differential modulation vernier permanent magnet motor can be obtained by substituting (2)(12)(18) into (4)(13), and its excitation flux density expression is equation (19) and the torque expression is equation (20).

[0049] B PM ≈[F PM1 cos{Z2(θ1-θ m )}][P0+(-1) j P1cos(Z1θ1)]

[0050] ≈(-1) j B PM1 cos{(Z2-Z1)θ1-Z2θ m}+B PMh cos{Z2(θ1-θ m )}

[0051] =(-1) j B PM1 cos{pθ1-Z2θ m}+B PMh cos{Z2(θ1-θ m )} (19)

[0052]

[0053] For the existing "differential modulation" vernier permanent magnet motor, the coefficients in the corresponding formulas (3) and (4) are (-1)j , the corresponding part of the torque formula (13) will become The two components cancel each other out and the torque density is insufficient.

[0054] Therefore, when designing a vernier permanent magnet motor, researchers often do not use a differential modulation vernier permanent magnet motor in order to give full play to the advantages of the vernier permanent magnet motor's high torque density. This limits the range of pole-slot matching selection in the vernier permanent magnet motor design process, bringing difficulties to the design work.

[0055] Therefore, changing the harmonic coupling effect in the differential modulation vernier permanent magnet motor and improving the torque density of the differential modulation vernier permanent magnet motor are of great significance for expanding the pole-slot matching selection range of high-performance vernier permanent magnet motors. Summary of the invention

[0056] In view of the above problems, the present invention provides a design scheme for a novel differential modulation vernier permanent magnet motor. In order to solve the technical problems of low torque density of differential modulation pole slot matching permanent magnet vernier motor and small selection range of pole slot matching of permanent magnet vernier motor, a technical scheme of shifting the spatial position of the modulation unit by 180 electrical degrees is adopted. The main features of this technical scheme are that the spatial position of the root of the stator tooth remains unchanged, the spatial position of the motor winding coil remains unchanged, and through the design of the "V"-shaped stator teeth, the spatial position of the tooth top of the stator tooth is shifted by 180 electrical degrees.

[0057] Specifically, the present invention provides a differential modulation vernier permanent magnet motor with high torque density. The differential modulation vernier permanent magnet motor comprises an outer stator and an inner rotor. The outer stator is composed of a stator yoke (1), stator teeth and an armature winding (4) from the outside to the inside. The stator yoke (1) is a metal cylinder with V-shaped stator teeth connected inside. The armature winding (4) is between adjacent stator teeth. There is an air gap between the stator teeth and the outer surface of the inner rotor. The inner rotor is composed of a rotor permanent magnet (5), a rotor core (6) and a rotor shaft (7) from the outside to the inside. The rotor permanent magnet (5) and the rotor core (6) are cylindrical, and the rotor shaft (7) is cylindrical. The three are tightly sleeved and can rotate synchronously.

[0058] In a preferred implementation, the connection between the stator tooth and the stator yoke (1) is the stator tooth root (2), the other end of the stator tooth is close to the rotor permanent magnet (5), and is the stator tooth top (3), and there is an air gap between the stator tooth top (3) and the rotor permanent magnet (5).

[0059] In another preferred implementation, the stator tooth root (2) and the two stator tooth tops (3) thereon form a "V"-shaped structure, and the angle between the two stator tooth tops (3) on the same stator tooth root (2) ranges from 30 degrees to 170 degrees, such as 60-120 degrees, 50-130 degrees, etc., and can be adaptively adjusted according to the number and size of the stator teeth.

[0060] In another preferred implementation, the rotor permanent magnet (5) in the inner rotor is formed into a cylindrical shape by a plurality of permanent magnet blocks, which are surface mounted and radially magnetized, and adjacent permanent magnet blocks have opposite magnetic properties.

[0061] In another preferred implementation, the number of stator tooth roots (2) is Z1, the number of pole pairs of the rotor permanent magnet (5) is Z2, and the number of pole pairs of the armature winding (4) is p. The three meet the requirements of a differential modulation vernier permanent magnet motor, and must satisfy Z1=Z2-p.

[0062] In another preferred implementation, the permanent magnet motor structure can be used as a motor of a motor or a generator.

[0063] According to the setting method of "modulation unit spatial position offset 180 electrical degrees", the present invention can make the air gap permeance fundamental wave phase offset 180 electrical degrees, so that the modulation item magnetic field B PM1 (θ1,t) is reversed by 180 electrical degrees, so that the modulated magnetic field B PM1 The torque component T contributed by (θ1,t) PM1 In a permanent magnet vernier motor, the torque consists of two components: the torque component T contributed by the modulation magnetic field and PM1 The torque component T contributed by the non-modulation magnetic field PMh For a "differential modulation" motor where the modulation unit is not offset, T PM1 With T PMh The signs are opposite, and they cancel each other out, resulting in a low torque density. In this solution, the modulation unit (a structure composed of multiple stator teeth, etc.) is spatially offset by 180 electrical degrees, T PM1 The sign is reversed, and T PMh The signs are the same and they are superimposed on each other, thus increasing the torque density and solving the technical problem.

[0064] The beneficial effects brought by the present invention are as follows:

[0065] 1. By changing the design of conventional tooth tops, the present invention creatively points out the direction for improving the torque density of differential modulation vernier permanent magnet motors;

[0066] 2. It broadens the range of pole-slot matching selection in the design process of the vernier permanent magnet motor and eliminates the limitation of the pole-slot quantity relationship in the design work. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 Define a diagram for an angle

[0068] Figure 2 This is the planar structure diagram of a conventional differential modulation vernier permanent magnet motor.

[0069] Figure 3Schematic diagram of angle definition for conventional differential modulation vernier permanent magnet motor

[0070] Figure 4 The air gap permeance waveform of the conventional differential modulation vernier permanent magnet motor

[0071] Figure 5 Schematic diagram of the differential modulation vernier permanent magnet motor of the present invention

[0072] Figure 6 This is a planar structural diagram of the differential modulation vernier permanent magnet motor of the present invention.

[0073] Figure 7 Schematic diagram of angle definition of the differential modulation vernier permanent magnet motor of the present invention

[0074] Figure 8 The air gap permeance waveform of the differential modulation vernier permanent magnet motor of the present invention is

[0075] The numbers in the figure indicate: (1) stator yoke, (2) stator tooth root, (3) stator tooth top, (4) armature winding, (5) rotor permanent magnet, (6) rotor core, and (7) rotor shaft. DETAILED DESCRIPTION

[0076] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0077] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0078] Example

[0079] The air gap structure of this scheme is different from that of the conventional permanent magnet vernier motor. The main difference is that Figure 5 As shown, the spatial position of the modulation unit (stator tooth) of this solution is offset by 180 electrical degrees, while the modulation unit of the conventional permanent magnet vernier motor is not offset.

[0080] like Figure 5 and Figure 6 As shown, the differential modulation vernier permanent magnet motor of this embodiment includes a stator and rotor core, an armature winding and a permanent magnet.

[0081] The stator core is made of laminated silicon steel sheets, including a stator yoke 1 and stator teeth. The stator yoke 1 is located at the outermost side of the stator. The stator teeth are of a "V"-shaped structure. The bottom of the "V" is the stator tooth root 2, which is connected to the stator yoke 1. The other end of the "V" is close to the outer surface of the rotor and is the stator tooth top 3. The armature winding 4 is distributed between adjacent stator teeth.

[0082] The rotor core 6 is a circular ring structure, also made of laminated silicon steel sheets. The rotor permanent magnets 5 are bonded to its outer surface, and the magnetization directions of adjacent permanent magnet blocks are opposite. The rotor shaft 7 is cylindrical and sleeved inside the rotor core 6. The rotor permanent magnets 5, the rotor core 6, and the rotor shaft 7 are tightly sleeved and can rotate synchronously.

[0083] The stator tooth root 2 includes a first tooth root 21, a second tooth root 22, a third tooth root 23, etc., the stator tooth top 3 includes a first tooth top 31, a second tooth top 32, a third tooth top 33, etc., and the winding includes a first coil side 41, a second coil side 42, etc.

[0084] The number of stator tooth roots 2 is Z1, the number of rotor permanent magnet 5 pole pairs is Z2, and the number of armature winding 4 pole pairs is p. The three meet the requirements of differential modulation vernier permanent magnet motor, and must satisfy Z1=Z2-p.

[0085] The spacing between adjacent stator tooth roots 2 in the same motor is the same, and the number of stator tooth roots 2 can be set as needed and is not limited to the number shown in the figure.

[0086] The stator tooth root 2 and the two stator tooth tops 3 thereon form a "V"-shaped structure. Preferably, the angle between the two stator tooth tops 3 on the same stator tooth root 2 is in the range of 30 degrees to 170 degrees.

[0087] The air gap spacing between adjacent stator tooth tops 3 in the same motor is the same, and the preferred spacing range is 0.1 to 20 mm. The air gap spacing between the stator tooth tops 3 and the rotor permanent magnets 5 is the same. The thickness of the air gap is related to the power level of the motor, the selected permanent magnet material, and the processing and assembly process of the inner rotor and the outer stator. The preferred spacing range is 0.1 to 20 mm.

[0088] The armature winding 4 is composed of a plurality of winding wires, the number of which is greater than 2. Each winding wire is wound in two symmetrical tooth root gaps, and when working, electrical energy is output to the outside from both ends of the wire.

[0089] The rotor core, the stator yoke 1, the stator tooth roots 2 and the stator tooth tops 3 are all made of laminated silicon steel sheets.

[0090] Preferably, the permanent magnets 5 are surface mounted and radially magnetized, and adjacent permanent magnets are magnetized in opposite directions. Permanent magnet materials such as neodymium iron boron and samarium cobalt may be used.

[0091] The rotor shaft 7 is the geometric center of the inner rotor and serves as the rotor shaft. It is embedded in the rotor core 6 and is made of bearing steel.

[0092] The above permanent magnet motor structure can be used as a motor or a generator.

[0093] The torque density of the differential modulation vernier permanent magnet motor designed by the present invention is derived as follows:

[0094] Figure 7 The diagram is a schematic diagram of the angle definition of the differential modulation vernier permanent magnet motor of the present invention. The center of the stator is taken as the origin, and the center line of the first tooth root 21 and the second tooth root 22 is taken as the θ1 axis to establish a polar coordinate system. θ1 represents the mechanical angle in the stator coordinate system. The position of the center line of the kth tooth root is θ 1bk , the position of the center line of the kth tooth tip is θ 1tk , the position of the center line of the kth coil side is θ 1ck The center line of the first tooth root 21 and the second tooth root 22 is located at θ1 = 0, that is, θ 1b1 =θ 1b2 =0. The center line of the third tooth root 23 and the fourth tooth root 24 is located at θ1=0+2π / Z1, that is, θ 1b3 =θ 1b4 =0+2π / Z1, and so on. The center line of the first tooth top 31 and the second tooth top 32 is located at θ1=π / Z1, that is, θ 1t1 =θ 1t2 =π / Z1. The center line of the third tooth top 33 and the fourth tooth top 34 is located at θ1=π / Z1+2π / Z1, that is, θ 1t3 =θ 1t4 =π / Z1+2π / Z1. And so on. The first coil side 41 is placed in a slot surrounded by the second tooth top 22, the third tooth top 23, the second tooth root 32, and the third tooth root 33, and its center line is located at θ1=π / Z1, that is, θ 1c1 =π / Z1. The second coil side 42 is placed in a slot surrounded by the fourth tooth top 24, the fifth tooth top 25, the fourth tooth root 34, and the fifth tooth root 35, and its center line is located at θ1=π / Z1+2π / Z1, that is, θ 1c2 =π / Z1+2π / Z1, and so on.

[0095] The tooth top center line of the differential modulation vernier permanent magnet motor of the present invention is located at θ 1tk =π / Z1+k×2π / Z1, so the air gap permeance waveform is as follows Figure 8 As shown, the expression is formula (21).

[0096] P(θ1)=P0+(-1) j+1 P1cos(Z1θ1) (21)

[0097] The torque formula of the differential modulation vernier permanent magnet motor in the present invention can be obtained by substituting (2)(12)(21) into (4)(13), and its excitation flux density expression is formula (5), and the torque expression is formula (14).

[0098] B PM ≈[F PM1 cos{Z2(θ1-θ m )}][P0+(-1) j+1 P1cos(Z1θ1)]

[0099] ≈(-1) j+1 B PM1 cos{(Z2-Z1)θ1-Z2θ m}+B PMh cos{Z2(θ1-θ m )}

[0100] =(-1) j+1 B PM1 cos{pθ1-Z2θ m}+B PMh cos{Z2(θ1-θ m )} (5)

[0101]

[0102] It can be seen from the torque derivation process that compared with the conventional differential modulation vernier permanent magnet motor, the specially designed stator tooth top position of the differential modulation vernier permanent magnet motor in the present invention changes the phase of the air gap magnetic permeability and the excitation magnetic flux density, affecting the harmonic coupling process, so that the torque generated by the two groups of harmonics changes from mutual cancellation to mutual superposition, thereby achieving the improvement of the torque density of the differential modulation vernier permanent magnet motor. Through experimental comparison, under the same other conditions, the permanent magnet motor of the present invention has a torque density improvement of more than 50% compared with the conventional permanent magnet motor under low load.

[0103] In the scheme, the spatial position of the modulation unit is offset by 180 electrical degrees, which greatly improves the torque density of the "differential modulation" motor. When designing a vernier permanent magnet motor, if the designer adopts the air gap structure of this scheme, the differential modulation pole slot combination can be used to obtain high torque density. Therefore, this scheme broadens the selection range of the vernier permanent magnet motor pole slot combination.

Claims

1. A high torque density differential modulation vernier permanent magnet motor, characterized in that: The differential modulation vernier permanent magnet motor comprises an outer stator and an inner rotor. The outer stator is composed of a stator yoke (1), stator teeth and an armature winding (4) from the outside to the inside. The stator yoke (1) is a metal cylinder with V-shaped stator teeth connected inside. The armature winding (4) is between adjacent stator teeth. There is an air gap between the stator teeth and the outer surface of the inner rotor. The inner rotor is composed of a rotor permanent magnet (5), a rotor core (6) and a rotor shaft (7) from the outside to the inside. The rotor permanent magnet (5) is a stator core (6) and a rotor shaft (7). The magnet (5) and the rotor core (6) are cylindrical, and the rotor shaft (7) is cylindrical. The three are tightly connected and can rotate synchronously. The stator tooth root (2) is connected to the stator yoke (1). The other end of the stator tooth is close to the rotor permanent magnet (5) and is the stator tooth top (3). There is an air gap between the stator tooth top (3) and the rotor permanent magnet (5). The stator tooth root (2) and the two stator tooth tops (3) thereon form a "V"-shaped structure. The polar coordinate system is established with the center of the stator as the origin and the center lines of the first and second tooth roots as the θ1 axis. θ1 represents the mechanical angle in the stator coordinate system. The position of the center line of the kth tooth root is θ 1bk , the position of the center line of the kth tooth tip is θ 1tk , the position of the center line of the kth coil side is θ 1ck； The center line of the first tooth root and the second tooth root is located at θ1 = 0, that is, θ 1b1 =θ 1b2 =0; the center line of the third and fourth tooth roots is located at θ1=0+2π / Z1, that is, θ 1b3 =θ 1b4 =0+2π / Z1, and so on; the center line of the first tooth top and the second tooth top is located at θ1=π / Z1, that is, θ 1t1 =θ 1t2 =π / Z1; the center line of the third tooth top and the fourth tooth top is located at θ1=π / Z1+2π / Z1, that is, θ 1t3 =θ 1t4 =π / Z1+2π / Z1, and so on; the first coil side is placed in the slot surrounded by the second tooth top, the third tooth top, the second tooth root, and the third tooth root, and its center line is located at θ1=π / Z1, that is, θ 1c1 =π / Z1; the second coil side is placed in the slot surrounded by the fourth tooth top, the fifth tooth top, the fourth tooth root, and the fifth tooth root, and its center line is located at θ1=π / Z1+2π / Z1, that is, θ 1c2 =π / Z1+2π / Z1, and so on.

2. The differential modulation vernier permanent magnet motor according to claim 1, characterized in that: The included angle between two stator tooth tops (3) on the same stator tooth root (2) ranges from 30 degrees to 170 degrees.

3. The differential modulation vernier permanent magnet motor according to claim 1, characterized in that: The rotor permanent magnet (5) in the inner rotor is formed into a cylindrical shape by a plurality of permanent magnet blocks, and is surface mounted and radially magnetized, and adjacent permanent magnet blocks have opposite magnetic properties.

4. The differential modulation vernier permanent magnet motor according to claim 1, characterized in that: The number of stator tooth roots (2) is Z1, the number of pole pairs of the rotor permanent magnet (5) is Z2, and the number of pole pairs of the armature winding (4) is p. The three meet the requirements of a differential modulation vernier permanent magnet motor, and must satisfy Z1=Z2-p.

5. The differential modulation vernier permanent magnet motor according to claim 1, characterized in that: The permanent magnet motor structure can be used as a motor of a motor or a generator.

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