Method for designing high-torque permanent magnet motor based on modulation tooth editing and electronic equipment

Abstract

The invention relates to the technical field of motor design, and particularly discloses a method for designing a high-torque permanent magnet motor based on modulation tooth editing and electronic equipment, and the method comprises the steps: analyzing a magnetic field path generated by a permanent magnet on a rotor in a no-load state of the motor, selecting a basic unit to represent the whole rotor structure, and establishing an expression of permanent magnet magnetomotive force according to the basic unit; the distribution characteristics of modulation teeth on a stator are analyzed, a basic unit is selected to represent the whole stator structure, a periodic air gap magnetic conductance mathematical model is established according to the basic unit, and an expression of an air gap magnetic conductance function is obtained. On the basis of an analytical expression of the output torque, the high-contribution-ratio magnetic field harmonic characteristics are associated with specific design parameters of the motor modulation teeth, the influence rule of the modulation tooth parameters on the high-contribution-ratio magnetic field harmonic and the nonlinear characteristics of the high-contribution-ratio magnetic field harmonic are analyzed in detail, and therefore the harmonic efficiency improved by editing the modulation tooth width and the high-contribution-ratio magnetic field harmonic characteristic improved by editing the modulation tooth width are innovated. And finally, the design method of the output torque is improved.

Description

Technical Field

[0001] The invention relates to the technical field of motor design, and in particular to a method for designing a high-torque permanent magnet motor based on modulated tooth editing and an electronic device. Background Art

[0002] The magnetic field modulation permanent magnet motor introduces a magnetic field modulation module based on the permanent magnet motor. This module can adjust the input current according to the controlled permanent magnet motor itself and the external magnetic field conditions, thereby controlling the speed, torque, insulation resistance and other performance of the permanent magnet motor.

[0003] The working principle of the magnetic field modulation permanent magnet motor is different from that of the traditional permanent magnet motor, and its air gap magnetic field harmonic content is richer. This is because the presence of the modulation teeth in the air gap causes the change of the circumferential magnetic resistance of the air gap, and the magnetic flux always propagates along the path with the smallest magnetic resistance. Therefore, the magnetic flux generated by the permanent magnet and the armature winding will produce different paths on the circumference of the air gap, thereby forming harmonics of different orders. During the rotation process, the harmonics of the same order and speed in these harmonics couple with each other to produce electromagnetic torque. The change of the modulation tooth structure in the air gap is the key to modulating the magnetic field harmonics by the magnetic field modulation effect. However, how to give full play to the positive role of magnetic field harmonics and improve the output torque of the magnetic field modulation permanent magnet motor has always been a key and difficult point in research. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to some extent. To this end, the purpose of the present invention is to provide a method and electronic device for designing a high torque permanent magnet motor based on modulated tooth editing to improve the output torque of the magnetic field modulated permanent magnet motor.

[0005] To achieve the above object, a first embodiment of the present invention provides a method for designing a high torque permanent magnet motor based on modulated tooth editing, the method comprising:

[0006] When the motor is in the no-load state, the magnetic field path generated by the permanent magnet on the rotor is analyzed, a basic unit is selected to represent the entire rotor structure, and the expression of permanent magnet magnetomotive force is established accordingly;

[0007] Analyze the distribution characteristics of the modulated teeth on the stator, select a basic unit to represent the entire stator structure, and establish a periodic air gap permeability mathematical model based on it. The expression of the air gap permeability function is obtained from the model.

[0008] Multiply the permanent magnet magnetomotive force by the air gap permeance to calculate the air gap flux density expression when the motor is no-load;

[0009] Integrate the air gap flux density along the arc corresponding to the phase winding around the air gap circle to obtain the permanent magnet flux linkage expression of the phase winding.

[0010] Derivative the permanent magnet flux expression, and obtain the no-load back electromotive force expression;

[0011] Perform mathematical analysis on no-load back electromotive force and establish parameter expressions between motor output torque and structural parameters;

[0012] Analyze the influence of magnetic field harmonics of each order in the air gap magnetic field on the motor output torque, and evaluate the difference in the influence of magnetic field harmonics of different orders on the output torque;

[0013] Analyze the magnetic field harmonics that have a greater impact on the motor output torque, change the air gap magnetic resistance by editing the modulation tooth width, adjust the harmonic amplitude of the magnetic permeance harmonics at each harmonic order, and then change the harmonic amplitude of the air gap magnetic field, increase the magnetic field harmonics that have a greater impact on the motor output torque, and enhance the motor's no-load back electromotive force and output torque.

[0014] In some embodiments of the present invention, the expression of the permanent magnet magnetomotive force can be expressed as:

[0015]

[0016] In the formula, F j is the jth magnetomotive force amplitude; θ s is the mechanical angle of the motor stator; p r is the number of rotor permanent magnet pole pairs; j is a positive odd number.

[0017] In some embodiments of the present invention, first, the piecewise function expression of the air gap permeability Λ is obtained from the air gap permeability mathematical model as follows:

[0018]

[0019] Where g' is the equivalent air gap length of the air gap between the rotor and the stator corresponding to the end of the modulated tooth; μ0 is the vacuum permeability; h s is the modulating tooth height on the armature tooth; k s is the modulating tooth pitch ratio on the armature teeth; k p is the modulation tooth width ratio on the armature teeth; p f is the total number of motor modulation teeth; w o is the arc corresponding to the motor slot;

[0020] Among them, the modulation tooth pitch ratio k s and modulation tooth width ratio k p It can be expressed as:

[0021]

[0022] In the formula, w s , t spThey are respectively the inter-tooth arc of the two modulating teeth on the armature teeth and the arc corresponding to the modulating teeth on the armature teeth;

[0023] By decomposing the above piecewise function using the Fourier series method, the expression of the air gap permeability function can be obtained as follows:

[0024]

[0025] Where N s is the number of motor slots, θ s is the stator mechanical angle, i is the coefficient of the Fourier series, Λ i is the amplitude of the i-th permeance harmonic;

[0026] Where Λ0 represents the DC component of the air gap permeability, Λ i represents the i-th harmonic amplitude of the air gap permeability, which can be expressed as:

[0027]

[0028] In some embodiments of the present invention, the air gap flux density expression of the motor when it is unloaded can be expressed as:

[0029]

[0030] In some embodiments of the present invention, the permanent magnetic flux linkage Ψ A The expression is:

[0031]

[0032] In the formula, w s is the arc between the two modulating teeth of the armature teeth; t sp is the arc of the armature tooth modulation tooth; R0 is the air gap radius of the motor; L stk is the stacking length of the motor stator and rotor core; n s is the number of turns per phase winding of the motor.

[0033] In some embodiments of the present invention, the expression of the no-load back electromotive force is:

[0034]

[0035]

[0036] In the formula, k w is the winding factor of the motor.

[0037] In some embodiments of the present invention, the parameter expression between the motor output torque and the structural parameter is:

[0038]

[0039] To achieve the above-mentioned purpose, the second aspect of the present invention proposes an electronic device, including a memory, a processor and a computer program stored on the memory. When the computer program is executed by the processor, the above-mentioned method of designing a high-torque permanent magnet motor based on modulated tooth editing is implemented.

[0040] The method and electronic device for designing a high-torque permanent magnet motor based on modulation tooth editing in the embodiment of the present invention associate the high-contribution magnetic field harmonic characteristics with the specific design parameters of the motor modulation teeth based on the analytical expression of the output torque, and analyze in detail the influence of the modulation tooth parameters on the high-contribution magnetic field harmonics and their nonlinear characteristics, thereby innovating a design method for improving the harmonic efficiency by editing the modulation tooth width and ultimately improving the output torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of a method for designing a high-torque permanent magnet motor based on modulated tooth editing according to an embodiment of the present invention;

[0042] Figure 2 It is a schematic cross-sectional structure diagram of a high torque magnetic field modulation permanent magnet motor designed by editing and modulating tooth width according to an embodiment of the present invention;

[0043] Figure 3 It is a magnetomotive force analytical model diagram of a unit module in a rotor permanent magnet according to an embodiment of the present invention;

[0044] Figure 4 It is an analytical model diagram of the air gap permeability of a unit module in a stator modulation tooth according to an embodiment of the present invention;

[0045] Figure 5 is a diagram of harmonic composition in an air gap permeability function analyzed based on an air gap permeability analytical model in one embodiment of the present invention;

[0046] Figure 6 It is a harmonic composition diagram of the air gap magnetic flux function obtained by using a radial magnetic flux calculation method based on a magnetomotive force-permeability model in one embodiment of the present invention;

[0047] Figure 7 It is a graph of the contribution of each order harmonic in the air gap magnetic field to the torque based on the derived torque analytical expression in one embodiment of the present invention;

[0048] Figure 8 1 is a comparison diagram of the design features of the modulation tooth width structure in one embodiment of the present invention, wherein (a) is a traditional modulation tooth design, and (b) is an edited modulation tooth width design in the present invention;

[0049] Fig. 91 is a comparison diagram of the permeance function waveforms when different modulation tooth widths are designed in one embodiment of the present invention, wherein (a) is the permeance function waveform using the traditional modulation tooth design, and (b) is the permeance function waveform using the edited modulation tooth width design of the present invention;

[0050] Fig.10 is a comparison diagram of air gap permeance harmonics of a conventional design and a design of the present invention according to an embodiment of the present invention;

[0051] Fig.11 is a comparison diagram of air gap magnetic flux harmonics of a conventional design and a design of the present invention according to an embodiment of the present invention;

[0052] Fig.12 is a comparison diagram of the contribution of the air gap magnetic flux harmonics to the output torque of a conventional design and a design of the present invention in one embodiment of the present invention;

[0053] Fig.13 is a comparison diagram of the no-load back electromotive force fundamental amplitudes of a conventional design and a design of the present invention in one embodiment of the present invention;

[0054] Fig.14 is a comparison diagram of average output torque and torque ripple of a conventional design and a design of the present invention according to an embodiment of the present invention;

[0055] Fig.15 It is a schematic structural diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0056] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0057] The following describes a method and electronic device for designing a high-torque permanent magnet motor based on modulated tooth editing according to an embodiment of the present invention with reference to the accompanying drawings.

[0058] Figure 1 It is a flow chart of a method for designing a high-torque permanent magnet motor based on modulated tooth editing according to an embodiment of the present invention.

[0059] like Figure 1 As shown, the method for designing a high torque permanent magnet motor based on modulated tooth editing includes:

[0060] S1. When the motor is in the no-load state, analyze the magnetic field path generated by the permanent magnet on the rotor. Since the rotor structure is symmetrical and periodic, a basic unit can be selected to represent the entire rotor structure. The basic unit here refers to a simplified part representing the entire rotor structure, and the expression of the permanent magnet magnetomotive force is established based on this.

[0061] As an example, Figure 3 As shown in the figure, a basic unit of the rotor structure is modeled, where the expression of the permanent magnet magnetomotive force can be expressed as:

[0062]

[0063] In the formula, F j is the jth magnetomotive force amplitude; θ s is the mechanical angle of the motor stator; p r is the number of rotor permanent magnet pole pairs; j is a positive odd number.

[0064] S2. Analyze the distribution characteristics of the modulated teeth on the stator. Since the modulated teeth on the stator are usually distributed according to a certain rule, a basic unit can be selected to represent the entire stator structure, and a periodic air gap permeance mathematical model can be established based on this. The expression of the air gap permeance function is obtained from the model;

[0065] As an example, Figure 4 As shown, firstly, the piecewise function expression of the air gap permeability Λ is obtained from the mathematical model of the air gap permeability:

[0066]

[0067] Where g' is the equivalent air gap length of the air gap between the rotor and the stator corresponding to the end of the modulated tooth; μ0 is the vacuum permeability; h s is the modulating tooth height on the armature tooth; k s is the modulating tooth pitch ratio on the armature teeth; k p is the modulation tooth width ratio on the armature teeth; p f is the total number of motor modulation teeth; w o is the arc corresponding to the motor slot;

[0068] Among them, the modulation tooth pitch ratio k s and modulation tooth width ratio k p It can be expressed as:

[0069]

[0070] In the formula, w s , t sp They are respectively the inter-tooth arc of the two modulating teeth on the armature teeth and the arc corresponding to the modulating teeth on the armature teeth;

[0071] Then the Fourier series method can be used to decompose the piecewise function of the air gap permeability Λ, and the expression of the air gap permeability function can be obtained as follows:

[0072]

[0073] Where N s is the number of motor slots, θ s is the stator mechanical angle, i is the coefficient of the Fourier series, Λ i is the amplitude of the i-th permeance harmonic;

[0074] Where Λ0 represents the DC component of the air gap permeability, Λ i represents the i-th harmonic amplitude of the air gap permeability, which can be expressed as:

[0075]

[0076]

[0077] like Figure 5 As shown, the harmonic composition of the air gap permeability function analyzed based on the air gap permeability analytical model is demonstrated.

[0078] In the above expression of the air gap permeability function, it is very difficult to directly obtain a complete and accurate expression of the air gap permeability function. Therefore, by first obtaining the piecewise function expression, the problem can be simplified, so that the function form in each segment is relatively simple, easier to handle and analyze; and after obtaining the piecewise function expression, the Fourier series method is applied to decompose the function in each segment. The function in each segment is decomposed into the sum of a series of sine and cosine functions to obtain the final expression of the air gap permeability function, which should be able to more accurately reflect the actual changes in the air gap permeability.

[0079] S3. Multiply the permanent magnet magnetomotive force by the air gap permeability to calculate the air gap flux density expression when the motor is no-load.

[0080] As an example, when the motor is in a no-load state, the air gap flux density expression can be expressed as:

[0081]

[0082] It should be noted that the expression of air gap magnetic flux density can be used to analyze the harmonic composition of the air gap magnetic field. The analysis structure is as follows: Figure 6 As shown. From the harmonic expression and Figure 6It can be seen that the order of magnetic field harmonics is determined by the number of permanent magnet pole pairs and the number of modulated teeth, and when the number of permanent magnet pole pairs remains unchanged, the amplitude of each harmonic of magnetic flux density is determined by the amplitude of the corresponding harmonic of magnetic permeance. For example, the amplitude of the 21st harmonic of air gap magnetic flux density depends on the magnitude of the DC component Λ0 in the harmonic of magnetic permeance, the amplitude of the 1st harmonic of air gap magnetic flux density depends on the magnitude of the 20th harmonic of magnetic permeance, and so on.

[0083] S4. Integrate the air gap flux density along the arc corresponding to the phase winding around the air gap circle. The process of obtaining the integral is actually calculating the magnetic flux passing through the phase winding. Through the integral operation, we can obtain the total magnetic flux passing through one phase winding, that is, the permanent magnetic flux linkage. The permanent magnetic flux linkage of one phase winding Ψ A The expression can be expressed as:

[0084]

[0085] In the formula, w s is the arc between the two modulating teeth of the armature teeth; t sp is the arc of the armature tooth modulation tooth; R0 is the air gap radius of the motor; L stk is the stacking length of the motor stator and rotor core; n s is the number of turns per phase winding of the motor.

[0086] S5. Derivative the permanent magnet flux expression to obtain the no-load back electromotive force expression, which is:

[0087]

[0088] In the formula, k w is the winding factor of the motor.

[0089] S6. Perform mathematical analysis on the no-load back electromotive force and establish a parameter expression between the motor output torque and the structural parameters. The parameter expression can describe the quantitative relationship between the motor output torque and the motor's structural parameters (such as modulation tooth width, permanent magnet size, etc.) and the air gap flux density.

[0090] As an example, the parameter expression between the motor output torque and the structural parameters is:

[0091]

[0092] S7. Analyze the influence of magnetic field harmonics of various orders in the air gap magnetic field on the output torque of the motor, and evaluate the difference in influence between magnetic field harmonics of different orders on the output torque. Since the air gap magnetic field contains magnetic field harmonics of multiple orders, these magnetic field harmonics have different contributions to the output torque of the motor. Therefore, the key harmonics are located first. Through analysis and calculation, it can be determined which harmonics of different orders contribute more to the output torque and which contribute less.

[0093] It should be noted that this embodiment analyzes the harmonic characteristics of the magnetic field, constructs an analysis model for the contribution of each order of harmonics to the output torque, and divides the harmonics into two categories, namely high contribution ratio harmonics and low contribution ratio harmonics, by analyzing the contribution of each unit harmonic torque, which lays a foundation for research on improving harmonic efficiency.

[0094] S8. Analyze the magnetic field harmonics that have a greater impact on the motor output torque, change the air gap magnetic resistance by editing the modulation tooth width, adjust the harmonic amplitude of the magnetic permeance harmonics at each harmonic order, and then change the harmonic amplitude of the air gap magnetic field. By adjusting the parameters, reduce the amplitude of some magnetic field harmonics that contribute less to the output torque, and increase the amplitude of the magnetic field harmonics that contribute more to the output torque, thereby enhancing the no-load back EMF and output torque of the motor, thereby improving the performance of the motor.

[0095] The method for designing a high-torque permanent magnet motor based on modulation tooth editing in an embodiment of the present invention, based on the analytical expression of the output torque, associates the high-contribution magnetic field harmonic characteristics with the specific design parameters of the motor modulation teeth, and analyzes in detail the influence of the modulation tooth parameters on the high-contribution magnetic field harmonics and their nonlinear characteristics, thereby innovating a design method for improving the harmonic efficiency by editing the modulation tooth width, and ultimately improving the output torque of the permanent magnet motor.

[0096] In some embodiments of the present invention, step S7 is further analyzed based on the parameter expression between the motor output torque and the structural parameters, such as Figure 7 The contribution of each order harmonic in the air gap magnetic field to the torque is analyzed as shown in Figure 2. Figure 7 It can be found that the 21st harmonic contributes the most to the torque, followed by the 1st harmonic, the 11th harmonic contributes the third, and the 19th and 31st harmonics contribute negatively to the torque.

[0097] In some embodiments of the present invention, step S8 is further analyzed:

[0098] S81. From the difference in the contribution of each order harmonic to the torque, it can be known that when designing the permanent magnet motor structure, the output torque of the motor can be improved by increasing the 1st and 21st harmonics;

[0099] S82. Based on the analysis of step S3, it can be known that the main parameters affecting the 1st and 21st magnetic field harmonics are the DC component and the 20th harmonic component in the permeance harmonic. According to the air gap permeance analytical function, it can be found that when the modulation pitch ratio k s When fixed, edit the modulation tooth width ratio k p The size of can effectively adjust the harmonics of the permeance, so this method uses the method of editing the modulation tooth width to adjust the permeance harmonics and increase the 1st and 21st harmonic amplitudes of the air gap magnetic field;

[0100] S83, such as Figure 8 The comparison of the modulation tooth structure of the present invention ( Figure 8 .b) Compared with the traditional modulation tooth structure ( Figure 8 .a) features. It can be found that the width of the modulation teeth on the armature teeth of the present invention is obviously different from that of the traditional design. Fig. 9 The permeance function waveforms analyzed by the permeance model in step S2 are compared, where ( Fig. 9 .a) is the traditional design, where ( Fig. 9 .b) is designed by the present invention. It can be seen that the waveform of the magnetic permeability function has obvious differences. Fig.10 The changes in the amplitudes of the harmonics of the permeance function of the conventional design and the design of the present invention are compared, from which it can be found that the amplitudes of the DC component and the 20th harmonic component of the permeance function of the permanent magnet motor using the method of the present invention are significantly improved.

[0101] S84, Fig.11 The changes in the amplitude of each harmonic of the air gap flux density of the motors using the traditional design and the design of the present invention are compared. It can be found that the amplitude of the 1st harmonic and the 21st harmonic of the permanent magnet motor using the method of the present invention is significantly improved.

[0102] S85, Fig.12 The contribution of each harmonic of the air gap flux density to the output torque of the motors with the traditional design and the design of the present invention is compared. It can be found that the contribution of the 1st harmonic and the 21st harmonic of the motor of the present invention to the torque is significantly improved.

[0103] S86, Fig.13 The no-load back electromotive force fundamental amplitudes of the conventional design and the design of the present invention are compared, from which it can be seen that the no-load back electromotive force fundamental amplitude of the motor designed by the present invention is increased by about 10%.

[0104] S87, Fig.14 The average output torque and torque pulsation of the motors with the conventional design and the design of the present invention are compared. It can be seen that compared with the motor with the conventional design, when the output current amplitude is 10A, the torque pulsation is slightly improved when the design of the present invention is used, and the motor torque is increased from 23.6Nm to 26Nm.

[0105] Corresponding to the above-mentioned embodiments, the present invention further proposes a five-phase magnetic field modulation permanent magnet motor and an electronic device.

[0106] like Figure 2The figure shows a schematic cross-sectional structure diagram of a five-phase magnetic field modulation permanent magnet motor designed by a design method for editing the modulation tooth width, including a motor stator D1 and a motor rotor D2, an air gap D8 being provided between the motor stator D1 and the motor rotor D2, the motor stator D1 including 10 armature teeth D6, each armature tooth D6 being wound with an armature winding D5, each set of armature winding D5 having 45 turns, each armature tooth D6 being split into two modulation teeth D4 near the air gap D8, the motor stator D1 including 10 auxiliary teeth D7, the auxiliary teeth D7 being a straight tooth structure, including one modulation tooth D4; the motor rotor D2 having a total of 42 permanent magnets D3, the 42 permanent magnets D3 being evenly distributed on the motor rotor D2, and the permanent magnets D3 being alternately magnetized along the radial direction.

[0107] like Fig.15 The figure shows a schematic diagram of the structure of an electronic device in the present invention, where the electronic device 200 includes: a processor 201 and a memory 203. The processor 201 and the memory 203 are connected, such as through a bus 202. Optionally, the electronic device 200 may further include a transceiver 204. It should be noted that in actual applications, the transceiver 204 is not limited to one, and the structure of the electronic device 200 does not constitute a limitation on the embodiments of the present invention.

[0108] The processor 201 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of the present invention. The processor 201 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0109] The bus 202 may include a path to transmit information between the above components. The bus 202 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus 202 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 2Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0110] The memory 203 is used to store a computer program corresponding to the method for designing a high-torque permanent magnet motor based on modulated tooth editing according to the above embodiment of the present invention, and the computer program is controlled and executed by the processor 201. The processor 201 is used to execute the computer program stored in the memory 203 to implement the contents shown in the above method embodiment.

[0111] The electronic device 200 includes, but is not limited to, mobile terminals such as laptop computers, PADs (tablet computers), and fixed terminals such as desktop computers. Figure 2 The electronic device 200 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0112] The electronic device 200 of the embodiment of the present invention can establish a magnetomotive force-permeability analytical model according to the stator, rotor, and permanent magnet structure of the magnetic field modulated permanent magnet motor, and derive the functional analytical expressions of the air gap permeability, magnetic density, no-load back electromotive force and output torque based on the analytical model; based on the analytical expressions, analyze the contribution value of each order of harmonics to the output torque, and qualitatively analyze the difference in the contribution of each order of harmonics to the torque; locate the harmonic order that contributes more to the torque, change the size of the air gap magnetic resistance by adopting the design of editing the modulation tooth width, adjust the amplitude of each order of permeability harmonics, and then adjust the amplitude of the air gap magnetic field harmonics, and finally sacrifice some harmonics that contribute less to the output torque and improve the harmonics that contribute more to the output torque, thereby improving the no-load back electromotive force and output torque of the motor.

[0113] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing in a suitable manner if necessary, and then stored in a computer memory.

[0114] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0115] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0116] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0117] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for designing a high torque permanent magnet motor based on modulated tooth editing, characterized in that: The method comprises: When the motor is in the no-load state, the magnetic field path generated by the permanent magnet on the rotor is analyzed, a basic unit is selected to represent the entire rotor structure, and the expression of permanent magnet magnetomotive force is established accordingly; Analyze the distribution characteristics of the modulated teeth on the stator, select a basic unit to represent the entire stator structure, and establish a periodic air gap permeability mathematical model based on it. The expression of the air gap permeability function is obtained from the model. Multiply the permanent magnet magnetomotive force by the air gap permeance to calculate the air gap flux density expression when the motor is no-load; Integrate the air gap flux density along the arc corresponding to the phase winding around the air gap circle to obtain the permanent magnet flux linkage expression of the phase winding. Derivative the permanent magnet flux expression, and obtain the no-load back electromotive force expression; Perform mathematical analysis on no-load back electromotive force and establish parameter expressions between motor output torque and structural parameters; Analyze the influence of magnetic field harmonics of each order in the air gap magnetic field on the motor output torque, and evaluate the difference in the influence of magnetic field harmonics of different orders on the output torque; Analyze the magnetic field harmonics that have a greater impact on the motor output torque, change the air gap magnetic resistance by editing the modulation tooth width, adjust the harmonic amplitude of the magnetic permeance harmonics at each harmonic order, and then change the harmonic amplitude of the air gap magnetic field, increase the magnetic field harmonics that have a greater impact on the motor output torque, and enhance the motor's no-load back electromotive force and output torque.

2. The method for designing a high torque permanent magnet motor based on modulated tooth editing according to claim 1, characterized in that: The expression of the permanent magnet magnetomotive force can be expressed as: In the formula, F j is the jth magnetomotive force amplitude; θ s is the mechanical angle of the motor stator; p r is the number of rotor permanent magnet pole pairs; j is a positive odd number.

3. The method for designing a high torque permanent magnet motor based on modulated tooth editing according to claim 2, characterized in that: First, the piecewise function expression of the air gap permeability Λ is obtained from the mathematical model of the air gap permeability: Where g' is the equivalent air gap length of the air gap between the rotor and the stator corresponding to the end of the modulated tooth; μ0 is the vacuum permeability; h s is the modulating tooth height on the armature tooth; k s is the modulating tooth pitch ratio on the armature teeth; k p is the modulation tooth width ratio on the armature teeth; p f is the total number of motor modulation teeth; w o is the arc corresponding to the motor slot; Among them, the modulation tooth pitch ratio k s and modulation tooth width ratio k p It can be expressed as: In the formula, w s , t sp are the inter-tooth arc of the two modulating teeth on the armature teeth and the arc corresponding to the modulating teeth on the armature teeth respectively; the above piecewise function is decomposed by Fourier series method, and the expression of the air gap permeability function can be obtained as follows: Where N s is the number of motor slots, θ s is the stator mechanical angle, i is the coefficient of the Fourier series, Λ i is the amplitude of the i-th permeance harmonic; Where Λ0 represents the DC component of the air gap permeability, Λ i represents the i-th harmonic amplitude of the air gap permeability, which can be expressed as:

4. The method for designing a high torque permanent magnet motor based on modulated tooth editing according to claim 3, characterized in that: The air gap flux density expression of the motor when it is unloaded can be expressed as:

5. The method for designing a high torque permanent magnet motor based on modulated tooth editing according to claim 4, characterized in that: The permanent magnetic flux linkage Ψ A The expression is: In the formula, w s is the arc between the two modulating teeth of the armature teeth; t sp is the arc of the armature tooth modulation tooth; R0 is the air gap radius of the motor; L stk is the stacking length of the motor stator and rotor core; n s is the number of turns per phase winding of the motor.

6. The method for designing a high torque permanent magnet motor based on modulated tooth editing according to claim 5, characterized in that: The expression of the no-load back electromotive force is: In the formula, k w is the winding factor of the motor.

7. The method for designing a high torque permanent magnet motor based on modulated tooth editing according to claim 6, characterized in that: The parameter expression between the motor output torque and the structural parameters is:

8. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory. When the computer program is executed by the processor, the method for designing a high-torque permanent magnet motor based on modulated tooth editing as described in any one of claims 1 to 7 is implemented.

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