A method for calculating the magnetic circuit of a synchronous reluctance motor

Abstract

The present invention discloses a method for calculating the magnetic circuit of a synchronous reluctance motor, comprising: analyzing and processing the rotor magnetomotive force of different layers of magnetic barrier structures of the synchronous reluctance motor to obtain rotor magnetomotive force expressions of the different layers of magnetic barrier structures, and using the rotor magnetomotive force expressions of the different layers of magnetic barrier structures to obtain a general rotor magnetomotive force equation for any layer of magnetic barrier structures; using the general rotor magnetomotive force equation for any layer of magnetic barrier structures to calculate the air gap flux density of the synchronous reluctance motor; and using the air gap flux density of the synchronous reluctance motor to calculate the electromagnetic torque output by the synchronous reluctance motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a method for calculating the magnetic circuit of a synchronous reluctance motor. Background Art

[0002] With the rapid development of the industrial sector, especially the widespread adoption of new energy electric vehicles, the demand for electric motors is increasing across the world's industrial powers. Currently, permanent magnet motors and induction motors are the most commonly used motors in industrial applications. Permanent magnet motors offer higher electromagnetic properties, such as power density, torque density, and efficiency, compared to other motor types. However, with the dwindling reserves and rising prices of rare metals (especially high-performance permanent magnets such as neodymium iron boron), the cost of permanent magnet motors is unmanageable. Permanent magnets are subject to the risk of demagnetization at high temperatures, and their sustainable development is uncertain. Induction motors offer easy starting, a wide speed range, and durability, but their unique rotor structure results in higher copper losses, leading to relatively low efficiency. Against this backdrop, synchronous reluctance motors (SRMs), with their higher power density, torque density, and efficiency compared to induction motors, wider speed range, and lower cost compared to permanent magnet motors, are gaining global attention.

[0003] Compared to other types of motors, the output torque of a synchronous reluctance motor depends on the d / q axis salient pole ratio—the ratio of the inductances between the d / q axes. Because a synchronous reluctance motor's rotor does not use permanent magnets or conductors, its salient pole ratio is entirely determined by the rotor structure. To maximize the salient pole ratio, synchronous reluctance motors typically have several layers of arcuate slots along the q axis of the rotor to increase the d-axis inductance and reduce the q-axis inductance. This results in a very complex rotor structure for synchronous reluctance motors. However, due to the long time required for finite element simulation and the high cost of prototype testing, neither of the above methods is suitable for the structural design and performance optimization of synchronous reluctance motors. Therefore, a fast and accurate method for calculating the magnetic circuit of a synchronous reluctance motor is of great significance for the initial design, sizing, and structural optimization of synchronous reluctance motors. Summary of the Invention

[0004] The present invention provides a method for calculating the magnetic circuit of a synchronous reluctance motor, so as to solve the technical problem of how to quickly and accurately calculate the magnetic circuit of a synchronous reluctance motor.

[0005] An embodiment of the present invention provides a method for calculating the magnetic circuit of a synchronous reluctance motor, which is characterized by comprising:

[0006] By analyzing and processing the rotor magnetomotive force of the synchronous reluctance motor with different layers of magnetic barrier structures, the rotor magnetomotive force expressions of the different layers of magnetic barrier structures are obtained, and the rotor magnetomotive force general equation of the rotor magnetomotive force of any layer of magnetic barrier structure is obtained by using the rotor magnetomotive force expressions of the different layers of magnetic barrier structures.

[0007] Calculate the air gap flux density of the synchronous reluctance motor using the general equation of the rotor magnetomotive force of the arbitrary layer magnetic barrier structure;

[0008] The electromagnetic torque output by the synchronous reluctance motor is calculated using the air gap flux density of the synchronous reluctance motor.

[0009] Preferably, the calculating of the air gap flux density of the synchronous reluctance motor by using the universal equation of the rotor magnetomotive force of the arbitrary-layer magnetic barrier structure includes:

[0010]

[0011] Among them, B g (θ s ) is the air gap magnetic density; μ0 is the vacuum magnetic permeability; L g is the air gap length; U s (θ s ) is the stator magnetomotive force; U r (θ s ) is the rotor magnetomotive force.

[0012] Preferably, the calculating the electromagnetic torque output by the synchronous reluctance motor by using the air gap flux density of the synchronous reluctance motor comprises:

[0013]

[0014] Among them, τ m is the Lorentz force density; D is the rotor outer diameter; L stk is the electromagnetic torque.

[0015] Preferably, the rotor magnetomotive force expressions of the different magnetic barrier structures of the synchronous reluctance motor are obtained by analyzing and processing the rotor magnetomotive force of the different magnetic barrier structures, including:

[0016] Constructing a rotor monopole linearized structure with one layer of magnetic barriers, and obtaining a rotor monopole equivalent magnetic circuit model with one layer of magnetic barriers by using the rotor monopole linearized structure with one layer of magnetic barriers;

[0017] Obtaining rotor magnetomotive forces in three regions of the rotor monopole linear structure of the one-layer magnetic barrier using the rotor monopole linear structure of the one-layer magnetic barrier and a rotor monopole equivalent magnetic circuit model of the one-layer magnetic barrier;

[0018] The rotor magnetomotive force of the three regions in the rotor monopole linear structure of the one-layer magnetic barrier is used to obtain a final expression of the rotor magnetomotive force of the rotor monopole linear structure of the one-layer magnetic barrier.

[0019] Preferably, the final expression of the rotor magnetomotive force of the rotor single-pole linear structure of the one-layer magnetic barrier includes:

[0020]

[0021] Among them, θ s e is the electrical angle of the stator reference coordinate axis; ω me is the motor speed in electrical degrees.

[0022] Preferably, the rotor magnetomotive force expressions of the different magnetic barrier structures of the synchronous reluctance motor are obtained by analyzing and processing the rotor magnetomotive force of the different magnetic barrier structures, including:

[0023] Constructing a rotor monopole linearized structure with two layers of magnetic barriers, and using the rotor monopole linearized structure with two layers of magnetic barriers to obtain a rotor monopole equivalent magnetic circuit model with two layers of magnetic barriers;

[0024] Using the rotor monopole linear structure of the two-layer magnetic barrier and the rotor monopole equivalent magnetic circuit model of the two-layer magnetic barrier, the rotor magnetomotive force of five regions in the rotor monopole linear structure of the two-layer magnetic barrier is obtained;

[0025] The rotor magnetomotive force of the five regions in the rotor monopole linear structure of the two-layer magnetic barrier is used to obtain a final expression of the rotor magnetomotive force of the rotor monopole linear structure of the two-layer magnetic barrier.

[0026] Preferably, the final expression of the rotor magnetomotive force of the rotor single-pole linear structure of the two-layer magnetic barrier includes:

[0027]

[0028] Preferably, the rotor magnetomotive force expressions of the different magnetic barrier structures of the synchronous reluctance motor are obtained by analyzing and processing the rotor magnetomotive force of the different magnetic barrier structures, including:

[0029] Constructing a rotor monopole linearized structure with three layers of magnetic barriers, and using the rotor monopole linearized structure with three layers of magnetic barriers to obtain a rotor monopole equivalent magnetic circuit model with three layers of magnetic barriers;

[0030] Using the rotor monopole linear structure of the three-layer magnetic barrier and the rotor monopole equivalent magnetic circuit model of the three-layer magnetic barrier, the rotor magnetomotive force of seven regions in the rotor monopole linear structure of the three-layer magnetic barrier is obtained;

[0031] The rotor magnetomotive force of the seven regions in the rotor monopole linear structure of the three-layer magnetic barrier is used to obtain a final expression of the rotor magnetomotive force of the rotor monopole linear structure of the three-layer magnetic barrier.

[0032] Preferably, the final expression of the rotor magnetomotive force of the rotor single-pole linear structure with three-layer magnetic barriers includes:

[0033]

[0034] Preferably, the general equation of the rotor magnetomotive force includes:

[0035]

[0036] Among them, G is the factor matrix; U r is the rotor magnetomotive force generated by each layer of magnetic barriers, θ b e is the magnetic barrier angle.

[0037] The beneficial effect of the present invention is that by establishing an accurate and effective equivalent magnetic circuit of the synchronous reluctance motor, the magnetomotive force expression of the synchronous reluctance motor rotor under an arbitrary layer of magnetic barrier structure is derived, and then the air gap magnetic density and electromagnetic torque expressions are obtained, which facilitates the synchronous reluctance motor designer to quickly determine the rotor structure of the motor, especially the number and size of the rotor magnetic barriers, in the initial design stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flow chart of a method for calculating the magnetic circuit of a synchronous reluctance motor provided by the present invention;

[0039] Figure 2 This is a schematic diagram of the current surface of the stator slot provided by the present invention to replace the traditional stator slot;

[0040] Figure 3 This is a schematic diagram of the distribution of the monopole lower conductor provided by the present invention;

[0041] Figure 4 This is a schematic diagram of the rotor single-pole linear structure with a single magnetic barrier provided by the present invention;

[0042] Figure 5 This is a schematic diagram of the equivalent magnetic circuit of a rotor monopole with a single layer of magnetic barriers provided by the present invention;

[0043] Figure 6 This is a schematic diagram of the rotor single-pole straight line structure of the two-layer magnetic barrier provided by the present invention;

[0044] Figure 7 This is a schematic diagram of the rotor single-pole equivalent magnetic circuit of the two-layer magnetic barrier provided by the present invention;

[0045] Figure 8 This is a schematic diagram of the rotor single-pole linearization structure of the three-layer magnetic barrier provided by the present invention;

[0046] Figure 9 This is a schematic diagram of the equivalent magnetic circuit of a rotor monopole with three layers of magnetic barriers provided by the present invention. DETAILED DESCRIPTION

[0047] It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. In the subsequent description, suffixes such as "module," "component," or "unit" used to denote components are used solely to facilitate the description of the present invention and have no inherent meaning. Therefore, "module," "component," or "unit" may be used interchangeably.

[0048] Based on the above needs, the present invention is based on the structural characteristics of the synchronous reluctance motor. According to the equivalent magnetic resistance of each rotor region, a single-pole structure of the rotor is taken as the research object, the rotor region partition is constructed, and the equivalent magnetic circuit model of the synchronous reluctance motor rotor is established. The stator and rotor magnetomotive force equations are derived, thereby obtaining the expressions of electromagnetic properties such as air gap magnetic density and electromagnetic torque, revealing the relationship between the electromagnetic performance of the synchronous reluctance motor and the motor structural parameters and electromagnetic parameters, and finally forming a new method for calculating the magnetic circuit of the synchronous reluctance motor.

[0049] Figure 1 This is a flow chart of a method for calculating the magnetic circuit of a synchronous reluctance motor provided by the present invention. Figure 1 As shown, the method includes: step S101: analyzing and processing the rotor magnetomotive force of different layers of magnetic barrier structures of the synchronous reluctance motor to obtain rotor magnetomotive force expressions of different layers of magnetic barrier structures, and using the rotor magnetomotive force expressions of different layers of magnetic barrier structures to obtain a general rotor magnetomotive force equation of any layer of magnetic barrier structure; step S102: using the general rotor magnetomotive force equation of any layer of magnetic barrier structure to calculate the air gap flux density of the synchronous reluctance motor; step S103: using the air gap flux density of the synchronous reluctance motor to calculate the electromagnetic torque output by the synchronous reluctance motor.

[0050] The calculation of the air gap flux density of the synchronous reluctance motor using the general equation of the rotor magnetomotive force of the arbitrary-layer magnetic barrier structure includes:

[0051]

[0052] Among them, B g (θ s ) is the air gap magnetic density; μ0 is the vacuum magnetic permeability; L g is the air gap length; U s (θ s ) is the stator magnetomotive force; U r (θ s ) is the rotor magnetomotive force.

[0053] The calculating of the electromagnetic torque output by the synchronous reluctance motor by using the air gap flux density of the synchronous reluctance motor includes:

[0054]

[0055] Among them, τm is the Lorentz force density; D is the rotor outer diameter; L stk is the electromagnetic torque.

[0056] Specifically, the analysis and processing of the rotor magnetomotive force of different layers of magnetic barrier structures of the synchronous reluctance motor to obtain the rotor magnetomotive force expression of different layers of magnetic barrier structures includes: constructing a rotor monopole linearized structure of one layer of magnetic barrier, and using the rotor monopole linearized structure of the one layer of magnetic barrier to obtain a rotor monopole equivalent magnetic circuit model of one layer of magnetic barrier; using the rotor monopole linearized structure of the one layer of magnetic barrier and the rotor monopole equivalent magnetic circuit model of the one layer of magnetic barrier to obtain the rotor magnetomotive force of three regions in the rotor monopole linearized structure of the one layer of magnetic barrier; using the rotor magnetomotive force of three regions in the rotor monopole linearized structure of the one layer of magnetic barrier to obtain the final expression of the rotor magnetomotive force of the rotor monopole linearized structure of the one layer of magnetic barrier.

[0057] The final expression of the rotor magnetomotive force of the rotor single-pole linear structure of the magnetic barrier layer includes:

[0058]

[0059] Among them, θ s e is the electrical angle of the stator reference coordinate axis; ω me is the motor speed in electrical degrees.

[0060] Specifically, the analysis and processing of the rotor magnetomotive force of different layers of magnetic barrier structures of the synchronous reluctance motor to obtain the rotor magnetomotive force expression of different layers of magnetic barrier structures includes: constructing a rotor monopole linearized structure of a two-layer magnetic barrier, and using the rotor monopole linearized structure of the two-layer magnetic barrier to obtain a rotor monopole equivalent magnetic circuit model of the two-layer magnetic barrier; using the rotor monopole linearized structure of the two-layer magnetic barrier and the rotor monopole equivalent magnetic circuit model of the two-layer magnetic barrier to obtain the rotor magnetomotive force of five regions in the rotor monopole linearized structure of the two-layer magnetic barrier; using the rotor magnetomotive force of the five regions in the rotor monopole linearized structure of the two-layer magnetic barrier to obtain the final expression of the rotor magnetomotive force of the rotor monopole linearized structure of the two-layer magnetic barrier.

[0061] The final expression of the rotor magnetomotive force of the rotor single-pole linear structure with two-layer magnetic barriers includes:

[0062]

[0063] Specifically, the analysis and processing of the rotor magnetomotive force of different layers of magnetic barrier structures of the synchronous reluctance motor to obtain the rotor magnetomotive force expression of different layers of magnetic barrier structures includes: constructing a rotor monopole linearized structure of three layers of magnetic barriers, and using the rotor monopole linearized structure of the three layers of magnetic barriers to obtain a rotor monopole equivalent magnetic circuit model of the three layers of magnetic barriers; using the rotor monopole linearized structure of the three layers of magnetic barriers and the rotor monopole equivalent magnetic circuit model of the three layers of magnetic barriers to obtain the rotor magnetomotive force of seven regions in the rotor monopole linearized structure of the three layers of magnetic barriers; using the rotor magnetomotive force of the seven regions in the rotor monopole linearized structure of the three layers of magnetic barriers to obtain the final expression of the rotor magnetomotive force of the rotor monopole linearized structure of the three layers of magnetic barriers.

[0064] The final expression of the rotor magnetomotive force of the rotor single-pole linear structure with three-layer magnetic barriers includes:

[0065]

[0066] Specifically, the general equation of the rotor magnetomotive force includes:

[0067]

[0068] Among them, G is the factor matrix; U r is the rotor magnetomotive force generated by each layer of magnetic barriers, θ b e is the magnetic barrier angle.

[0069] The technical content of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0070] 1. Stator magnetomotive force

[0071] In order to simplify the analysis process of the stator magnetomotive force, the influence of the stator slot reaction and the stator slot opening is ignored, and the equivalent current surface is used to replace the traditional distributed winding stator slot to analyze the stator magnetomotive force, such as Figure 2 As shown. Figure 2 The current surface shown in the figure is further simplified to obtain Figure 3 The winding distribution is shown in Figure 1. d (θ s e ) is the conductor current density on the equivalent current surface. First, consider the effect of single-turn winding, which can be expressed by formula (1)

[0072]

[0073] Among them, n d (θ s e ) is the conductor current density on the equivalent current surface, θ s eis the electrical angle of the position in the stator reference coordinate axis, D is the outer diameter of the rotor, and δ represents the current impulse function on the stator reference coordinate axis.

[0074] From formula (1), we can see that n d (θ s e ) is a half-periodic odd function equation, then its Fourier factor b v It can be expressed as:

[0075]

[0076] Wherein, v is the spatial harmonic order, and v=6k+1, (k=0, ±1, ±2, ±3…).

[0077] From equation (2), we can see that all even-order harmonics are eliminated due to the influence of sin(vπ / 2). At the same time, assuming that equations (1) and (2) are based on phase A, equation (2) can be simplified and extended to phases B and C. In this case, the equivalent current surface densities of the three phases are:

[0078]

[0079] Among them, k w v is the winding coefficient.

[0080] Then the three-phase currents at the stator end can be expressed as:

[0081]

[0082] At this time, the electrical load of the synchronous reluctance motor can be expressed by the following formula.

[0083]

[0084] Substituting equations (3) and (4) into equation (5), we can obtain:

[0085]

[0086] Among them, ω me is the motor speed in electrical degrees.

[0087] Consider the number of turns N of a single-phase winding s The influence on the model (the number of conductors in one turn of winding is 2), and to further simplify formula (6), the factor of formula (6) is set to K v , then from formula (6) we can get K v for

[0088]

[0089] Substituting equation (7) into equation (6), the current load of the symmetrical three-phase motor theoretical model can be obtained as

[0090]

[0091] For current load K s (θ s e ,t) and the polar arc width λ p Integrating the product of , we can get the expression of stator magnetomotive force:

[0092]

[0093] The pole arc width can be calculated by the following formula:

[0094]

[0095] Substituting equations (8) and (10) into equation (9), we can obtain

[0096]

[0097] 2. Rotor magnetomotive force

[0098] The rotor of a synchronous reluctance motor generally has a three-layer or four-layer magnetic barrier structure. In this invention, a theoretical model of the rotor magnetomotive force is derived using a three-layer magnetic barrier as an example, and ultimately a general theoretical model formula applicable to n (n = 1, 2, 3, ...) layers of magnetic barriers is obtained.

[0099] 2.1 Rotor magnetomotive force of a single-layer magnetic barrier structure

[0100] Firstly, the rotor structure of the synchronous reluctance motor with one layer of magnetic barrier is analyzed and derived. Figure 4 The figure shows the linear structure of the rotor with one layer of magnetic barrier. Figure 5 Shown is the corresponding equivalent magnetic circuit model.

[0101] exist Figure 4 In, θ b1 is half of the span angle of the first magnetic barrier; R g1 is the equivalent magnetic resistance in the air gap space corresponding to the first layer of magnetic barrier; R g2 With R g3 are the equivalent magnetic resistances in the air gap space corresponding to the rotor core on both sides of the first magnetic barrier; R b1 is the equivalent magnetic resistance of the magnetic barrier itself, and can be obtained from the following formula

[0102]

[0103] The rotor magnetomotive force can be calculated by the following formula:

[0104] U ri =φ biR bi , (13)

[0105] Among them, φ bi is the magnetic flux flowing through the magnetic barrier, i represents the i-th magnetic barrier (i=1,2,3,…). Then the magnetic flux flowing through the first magnetic barrier is b1 for

[0106]

[0107] Among them, L stk B is the axial length of the motor; g (θ s ) is the air gap flux density under the stator coordinate axis, and can be calculated from the stator magnetomotive force and the rotor magnetomotive force:

[0108]

[0109] Among them, L g is the air gap length.

[0110] Therefore, when only one layer of magnetic barrier is considered, U in Equation (15) r =U r1 , then substitute formula (15) into formula (14), and combine formula (12) and formula (13), we can get

[0111]

[0112] Will U r1 After combining like terms, we can get

[0113]

[0114] Let letter a represent all the motor structural parameters in formula (17), including rotor outer diameter, air gap length, axial length, magnetic barrier size, etc., then we have

[0115]

[0116] Substituting formula (18) into formula (17), formula (17) can be simplified to

[0117]

[0118] Let λ v =vπ / 2+p(v-1)ωt-α i e , then formula (19) can be further simplified to

[0119]

[0120] Then for the rotor magnetomotive force U at this time r (θ se ),according to Figure 4 , which satisfies

[0121]

[0122] It is easy to see that this function is an odd function, so its Fourier factor is

[0123]

[0124] Then the final expression of the rotor magnetomotive force under a magnetic barrier structure is:

[0125]

[0126] 2.2 Rotor magnetomotive force of the two-layer magnetic barrier structure

[0127] After theoretical analysis of the rotor magnetomotive force of a single-layer magnetic barrier, the rotor structure of the synchronous reluctance motor with a double-layer magnetic barrier is analyzed and deduced. Figure 6 The figure shows the linear structure of the rotor with two layers of magnetic barriers. Figure 7 Shown is the corresponding equivalent magnetic circuit model.

[0128] Depend on Figure 7 It can be seen that the rotor magnetomotive force of the second layer of magnetic barriers is formed by the rotor magnetomotive force of the first layer of magnetic barriers and the magnetic flux flowing through the first layer of magnetic barriers. Figure 7 Available

[0129] U r1 =φ b1 R b1 +U r2 . (twenty one)

[0130] Substituting equations (12) and (14) into equation (21), we have

[0131]

[0132] Let letter b = 1 / (1+Dt b1 θ b1 / L g l b1 ), and merge U in formula (22) r1 The similar terms of

[0133]

[0134] From formula (13), we can see

[0135] U r2 =φ b2 R b2 . (twenty four)

[0136] At the same time, by Figure 7 Easy to obtain

[0137] φ b2 =φ b1 -φ g2 -φ g3 , (25)

[0138] And φ b1 Satisfy at the same time

[0139]

[0140] Substituting equations (23), (25) and (26) into equation (24) simultaneously, we can obtain

[0141]

[0142] make

[0143]

[0144]

[0145] Then formula (27) can be simplified to

[0146]

[0147] Substituting equation (20) into equation (28), we can obtain the magnetomotive force generated by the second layer of magnetic barrier:

[0148]

[0149] Substituting equation (29) into equation (23), we can obtain the magnetomotive force generated by the first layer of magnetic barrier in the two-layer magnetic barrier rotor structure:

[0150]

[0151] Then for the rotor magnetomotive force U at this time r (θ s e ),according to Figure 6 , which satisfies

[0152]

[0153] Its Fourier factor is

[0154]

[0155] Then the final expression of the rotor magnetomotive force under a magnetic barrier structure is:

[0156]

[0157] From the above formula, we can see that when U r2=0, the equation is the same as the rotor magnetomotive force equation of a single-layer magnetic barrier structure.

[0158] 2.3 Rotor magnetomotive force of three-layer magnetic barrier structure

[0159] After analyzing and theoretically deriving the rotor magnetomotive force of the one-layer magnetic barrier structure and the two-layer magnetic barrier structure, the rotor magnetomotive force of the three-layer magnetic barrier structure is analyzed. Figure 8 The figure shows the linear structure of the rotor with three layers of magnetic barriers. Figure 9 Shown is the corresponding equivalent magnetic circuit model.

[0160] Similar to the analysis process of the rotor magnetomotive force of the two-layer magnetic barrier structure in the previous section, Figure 8 We can get:

[0161] U r2 =φb b2 R b2 +U r3 , (31)

[0162] and

[0163] φb b3 φb b2 -φ g4 -φ g5 (32)

[0164] Combining equations (13), (31) and (32), we can get

[0165] U r3 =(φ b2 -φ g4 -φ g5 )R b3 , (33)

[0166] Among them, φ g4 and φ g5 Represent the magnetic flux flowing only through the third magnetic barrier, such as Figure 9 As shown, it can be calculated by formula (34)

[0167]

[0168]

[0169] Substituting equations (12), (31) and (34) into equation (33), we can obtain

[0170]

[0171] By merging U r2 with U r3 and let

[0172]

[0173] At this time, we can get U r2 with U r3 The relationship is

[0174]

[0175] Depend on Figure 9 It can be seen that at this time, the U r1 with U r2 The relationship between U r2 The derivation process of has been introduced in detail in the previous section and will not be repeated here.

[0176] Similar to the derivation process of formulas (25)-(29), according to formula (37), let

[0177]

[0178] The third magnetic barrier U can be obtained r3 The expression is

[0179]

[0180] To simplify the above equations about the rotor magnetomotive force, the following factors are defined:

[0181]

[0182] as well as

[0183] ρ1={a+b[c-d+z(mn)]}sin(vpθb b1 )+{b[d+z(nq)]}sin(vpθ b2 )+bzqsin(vpθ b3 ),

[0184] ρ2=[c-d+z(mn)]sin(vpθ b1 )+[d+z(nq)]sin(vpθb b2 )+qzsin(vpθb b3 ), (41)

[0185] ρ3=(mn)sin(vpθb b1 )+(nq)sin(vpθb b2 )+qsin(vpθb b3 ).

[0186] Then, using the factors defined in equations (40) and (41), we can get U r1 、U r2 、Ur3 The expressions are

[0187]

[0188] Then for the rotor magnetomotive force U at this time r (θ s e ),according to Figure 8 , which satisfies

[0189]

[0190] Its Fourier factor is

[0191]

[0192] Then the final expression of the rotor magnetomotive force under a magnetic barrier structure is:

[0193]

[0194] From the above formula, we can see that when U r3 = 0, the equation is the same as the rotor magnetomotive force equation of the two-layer magnetic barrier structure; when U r2 =U r3 =0, the equation is the same as the rotor magnetomotive force equation of a single-layer magnetic barrier structure.

[0195] 2.4 Rotor magnetomotive force of n-layer magnetic barrier structure

[0196] By deriving and analyzing the rotor magnetomotive force equations for the structures of one layer of magnetic barriers, two layers of magnetic barriers, and three layers of magnetic barriers, we can see that the resulting equations are consistent and incremental, and thus the rotor magnetomotive force equations for the structure of n (n = 1, 2, 3, ...) layers of magnetic barriers can be derived. First, we can assume that the rotor magnetomotive force U generated by each layer of magnetic barriers is r and the magnetic barrier angle θ b e The matrices are

[0197]

[0198] Its Fourier factor can be expressed as

[0199]

[0200] Among them, G is the factor matrix, and its value is

[0201]

[0202] The final rotor magnetomotive force equation is

[0203]

[0204] 3. Air gap magnetic flux density

[0205] According to the stator magnetomotive force and rotor magnetomotive force equations derived above, the air gap flux density equation can be obtained as follows:

[0206]

[0207] Where μ0 is the vacuum permeability, L g is the air gap length.

[0208] 4. Electromagnetic torque

[0209] The output electromagnetic torque of the synchronous reluctance motor can be expressed by the Lorentz force density τ m The equation is obtained as

[0210]

[0211] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention shall fall within the scope of the present invention.

Claims

1. A method for calculating the magnetic circuit of a synchronous reluctance motor, characterized in that: include: By analyzing and processing the rotor magnetomotive force of the synchronous reluctance motor with different layers of magnetic barrier structures, the rotor magnetomotive force expressions of the different layers of magnetic barrier structures are obtained, and the rotor magnetomotive force expressions of the different layers of magnetic barrier structures are used to obtain the general rotor magnetomotive force equation of any layer of magnetic barrier structure; wherein the general rotor magnetomotive force equation includes: Among them, G is the factor matrix; U r is the rotor magnetomotive force generated by each layer of magnetic barriers, θ b e is the magnetic barrier angle; θ s e is the electrical angle of the stator reference coordinate axis; The air gap flux density of the synchronous reluctance motor is calculated using the general equation of the rotor magnetomotive force of the arbitrary layer magnetic barrier structure, which includes: Among them, B g (θ s ) is the air gap magnetic density; μ0 is the vacuum magnetic permeability; L g is the air gap length; U s (θ s ) is the stator magnetomotive force; U r (θ s ) is the rotor magnetomotive force; Calculating the electromagnetic torque output by the synchronous reluctance motor by using the air gap flux density of the synchronous reluctance motor includes: Among them, τ m is the Lorentz force density; D is the rotor outer diameter; L stk is the axial length of the motor.

2. The method according to claim 1, characterized in that By analyzing and processing the rotor magnetomotive force of the synchronous reluctance motor with different layers of magnetic barrier structures, the rotor magnetomotive force expressions of the different layers of magnetic barrier structures are obtained, including: Constructing a rotor monopole linearized structure with one layer of magnetic barriers, and obtaining a rotor monopole equivalent magnetic circuit model with one layer of magnetic barriers by using the rotor monopole linearized structure with one layer of magnetic barriers; Obtaining rotor magnetomotive forces in three regions of the rotor monopole linear structure of the one-layer magnetic barrier using the rotor monopole linear structure of the one-layer magnetic barrier and a rotor monopole equivalent magnetic circuit model of the one-layer magnetic barrier; The rotor magnetomotive force of the three regions in the rotor monopole linear structure of the one-layer magnetic barrier is used to obtain a final expression of the rotor magnetomotive force of the rotor monopole linear structure of the one-layer magnetic barrier.

3. The method according to claim 2, characterized in that The final expression of the rotor magnetomotive force of the rotor single-pole linear structure with one magnetic barrier includes: Among them, θ s e is the electrical angle of the stator reference coordinate axis; ω me is the motor speed in electrical degrees.

4. The method according to claim 1, wherein By analyzing and processing the rotor magnetomotive force of the synchronous reluctance motor with different layers of magnetic barrier structures, the rotor magnetomotive force expressions of the different layers of magnetic barrier structures are obtained, including: Constructing a rotor monopole linearized structure with two layers of magnetic barriers, and using the rotor monopole linearized structure with two layers of magnetic barriers to obtain a rotor monopole equivalent magnetic circuit model with two layers of magnetic barriers; Using the rotor monopole linear structure of the two-layer magnetic barrier and the rotor monopole equivalent magnetic circuit model of the two-layer magnetic barrier, the rotor magnetomotive force of five regions in the rotor monopole linear structure of the two-layer magnetic barrier is obtained; The rotor magnetomotive force of the five regions in the rotor monopole linear structure of the two-layer magnetic barrier is used to obtain a final expression of the rotor magnetomotive force of the rotor monopole linear structure of the two-layer magnetic barrier.

5. The method according to claim 4, characterized in that The final expression of the rotor magnetomotive force of the rotor single-pole linear structure with two layers of magnetic barriers includes:

6. The method according to claim 1, characterized in that By analyzing and processing the rotor magnetomotive force of the synchronous reluctance motor with different layers of magnetic barrier structures, the rotor magnetomotive force expressions of the different layers of magnetic barrier structures are obtained, including: Constructing a rotor monopole linearized structure with three layers of magnetic barriers, and using the rotor monopole linearized structure with three layers of magnetic barriers to obtain a rotor monopole equivalent magnetic circuit model with three layers of magnetic barriers; Using the rotor monopole linear structure of the three-layer magnetic barrier and the rotor monopole equivalent magnetic circuit model of the three-layer magnetic barrier, the rotor magnetomotive force of seven regions in the rotor monopole linear structure of the three-layer magnetic barrier is obtained; The rotor magnetomotive force of the seven regions in the rotor monopole linear structure of the three-layer magnetic barrier is used to obtain a final expression of the rotor magnetomotive force of the rotor monopole linear structure of the three-layer magnetic barrier.

7. The method according to claim 6, characterized in that The final expression of the rotor magnetomotive force of the rotor single-pole linear structure with three-layer magnetic barriers includes:

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