A multi-field dynamic coupling modeling method for medium and large motors based on multi-spatial scales

Abstract

A multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales, belonging to the field of motor technology. To solve the problems of the deficiencies of traditional motor modeling methods. The present invention determines the specific structure of the medium and large-sized motor and analyzes the research problems. The specific structure is the cooling system of the medium and large-sized motor, the stator and rotor cores under the casing, and the coils. The analysis of the research problems is the electromagnetic performance and the thermal performance. Determine the physical fields involved in the research problems. The physical fields include the electromagnetic field, the temperature field, and the fluid field. Establish a two-dimensional electromagnetic field model and conduct validity verification. Establish a fluid domain model based on multiple spatial scales and analyze the established fluid domain model. Establish a temperature field gradient model. Establish a multi-field dynamic coupling model for medium and large-sized motors based on multiple spatial scales. The present invention analyzes and processes according to the situation of the fields and the specific problems studied, which can not only ensure accuracy but also speed up the calculation time.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and particularly relates to a multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales. Background Art

[0002] Traditional cage-type three-phase induction motors are widely used in production practice due to their simple structure, reliable operation, etc. However, most of the research on cage-type induction motors is the analysis under their stable states, that is, steady-state coupling analysis. In the analysis and research of medium and large-sized induction motors, the electromagnetic transient process cannot be ignored, and there is a dynamic gradient in the electromagnetic transient process. When conducting traditional modeling analysis, the calculation of the flow-thermal problem during the electromagnetic dynamic process is often ignored. In electromagnetic research, due to the relatively long starting time of medium and large-sized motors, there are non-linear coupling relationships between various fields. When modeling according to the previous finite element method, the spatial distribution gradient of the current in the conductor during the transient process of the motor is often easily ignored, affecting the calculation accuracy; for the research of transient fluids, the traditional fluid modeling method does not focus on the laminar flow between the stator and rotor, so it cannot accurately describe the fluid changes of the motor at different speeds; when conducting temperature field analysis, most of the previous research is on the transient temperature field of small closed asynchronous motors under stable loads. For medium and large-sized motors, the temperature rise changes of the stator winding and rotor bars during motor starting are often ignored. Since the change gradients of the same physical field are different at different parts of the motor, when conducting motor temperature rise research, it is necessary to focus on gradient-based modeling of the stator winding and rotor bars of the motor to ensure the calculation accuracy of transient temperature rise. Summary of the Invention

[0003] The present invention solves the deficiencies of the above traditional motor modeling methods and proposes a multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales.

[0004] To achieve the above object, the present invention is realized through the following technical solutions:

[0005] A multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales includes the following steps:

[0006] S1. Determine the specific structure of the medium and large-sized motor and analyze the research problems. The specific structure is the cooling system, stator and rotor cores under the machine shell, and coils of the medium and large-sized motor. The research problem analysis is electromagnetic performance and thermal performance;

[0007] S2. Determine the physical fields involved in the research problems in step S1. The physical fields include electromagnetic field, temperature field, and fluid field (other fields are not reflected in the following research, so they are not added);

[0008] S3. Establish a two-dimensional electromagnetic field model and conduct validity verification;

[0009] S4. Based on multiple spatial scales, establish a fluid domain model and analyze the established fluid domain model;

[0010] S5. Establish a temperature field gradient model;

[0011] S6. Establish a multi-field dynamic coupling model for medium and large-sized motors based on multiple spatial scales.

[0012] Further, the method for establishing the two-dimensional electromagnetic field model in step S3 includes the following steps:

[0013] S3.1. Perform small-scale modeling on the stator winding and rotor bar parts of the medium and large-sized motor, conduct refined meshing on the stator winding and rotor bars, with the meshing shape being triangular meshing and the meshing setting value being 0.5 mm, and conduct meshing on the slot wedge insulation layer of the motor, with the meshing shape being triangular meshing and the meshing setting value being 0.1 mm; at the same time, layer the bars according to the bar embedding depth of the motor, select 10 - 15 layers, and according to the skin effect, set the meshing value of the 3 - 4 layers near the slot opening to 0.1 mm, and the meshing setting value of the remaining layered meshing to 0.5 mm;

[0014] S3.2. Perform large-scale modeling on the iron core and other components of the medium and large-sized motor, conduct refined meshing on the iron core and other components, with the meshing setting value being 1 mm and the meshing shape being triangular meshing;

[0015] S3.3. Use finite elements to perform current element area integral analysis to obtain the variation law of the losses of each layer of the motor bars during the dynamic process of the medium and large-sized motor;

[0016] S3.4. The core losses of the medium and large-sized motor are mainly concentrated in the stator teeth and stator yoke. The calculation formula for the core losses can be obtained by superimposing the two parts as follows:

[0017]

[0018] In the formula: K d and K' d are the loss increase coefficients of the yoke and teeth respectively, G fej and G fet are the weights of the yoke and teeth respectively, and are the unit losses of the yoke and teeth respectively, B j and are the maximum magnetic flux densities of the yoke and teeth respectively, f N is the frequency. Since the electromagnetic gradient change is not significant, take its calculation result as a constant value as the temperature rise heat source.

[0019] Further, the method for establishing the fluid domain model based on multiple spatial scales in step S4 includes the following steps:

[0020] S4.1. Divide the overall model into different domains according to the air flow direction and the complexity of each component structure:

[0021] S4.2. For medium and large motors, the stator and rotor cores have multiple radial ventilation ducts, and coils and bars pass through the middle, and the air flow is continuous, which serves as the core area;

[0022] S4.3, medium and large motors have a large number of stator winding slots, different winding methods, and complex end structures, which are used as end domains;

[0023] S4.4. According to the different cooling methods of medium and large motors, different areas are divided into blocks for processing;

[0024] S4.5. Small-scale modeling is performed in places where the fluid boundary layer gradient of medium and large motors is large, and it is divided into 0.5mm, and other areas are divided into 1mm;

[0025] S4.6. The fluid field changes of medium and large motors at different speeds are different. The stator and rotor laminar flow of medium and large motors are divided densely, and small-scale modeling is performed in the same way to obtain the fluid changes of medium and large motors at different speeds.

[0026] S4.7. At the end other than the fluid field, use it as a node of the fluid field for large-scale modeling;

[0027] S4.8. Simplify the parts that have little impact on the fluid field, including simplifying bearings, fans, and coolers.

[0028] Furthermore, step S5 of establishing the temperature field gradient model includes the following steps:

[0029] S5.1. For the stator winding part of medium and large motors, small-scale modeling is performed, the segmentation shape is triangular segmentation, and the segmentation setting value is 0.5mm. The slot wedge insulation layer of the motor is segmented, and the segmentation shape is triangular segmentation, and the segmentation setting value is 0.1mm;

[0030] S5.2. The rotor bar portion of medium and large motors is layered according to the layering method. The calculation method of the layered current of the rotor bar portion is:

[0031] S5.2.1. Calculate the current value of the motor bar at a certain moment using computer finite element simulation software. 总 ;

[0032] S5.2.2, set the current value of the first layer in the rotor slot to I 1 , then the formula for the stratified current of the rotor bar part is:

[0033]

[0034] Among them, are the currents of the i-th layer and the (i + 1)-th layer of the rotor bar part respectively, and R i , R i+1 are the DC resistances of the i-th layer and the (i + 1)-th layer of the rotor bar part respectively, X i is the leakage reactance of the i-th layer of the rotor bar part, j is the imaginary unit, is the current value of each layer of the bar, and k is the layer number;

[0035] X i = ωμl h i / b i

[0036] Among them, ω is the angular velocity, μ is the magnetic permeability, l is the length of the bar, h i is the height value of the i-th layer after the bar is stratified, and b i is the width value of the i-th layer after the bar is stratified; thus, the current of the i-th layer is calculated. At this time, the currents of each layer are all functions of the current value of the first layer;

[0037] S5.2.3. Solve the system of equations with I 1 as the variable, and gradually deduce the proportion of the current of each layer of the bar in the total current value I 总 , and then multiply the actual value I 总 of the bar current by the proportion of the current of each layer of the bar to obtain the actual value of the current of each layer. Finally, observe the current value of each layer of the rotor bar, and obtain the degree of skin effect in the rotor from the current distribution of the bar;

[0038] S5.3. For the stator and rotor cores of medium and large motors, perform large-scale modeling.

[0039] Furthermore, step S6 of establishing a multi-field dynamic coupling model of medium and large motors based on multiple spatial scales includes unidirectional weak coupling, unidirectional strong coupling, bidirectional weak coupling, and bidirectional strong coupling.

[0040] Advantages of the present invention:

[0041] A multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales according to the present invention analyzes based on the specific structure of the motor under study and the problems to be studied; according to the analysis results, the physical fields involved in the problems to be studied are determined. For the coupled analysis of large motors, it involves the electromagnetic field, fluid field, and temperature field. Then, according to the problems to be studied, a two-dimensional electromagnetic field model of the motor is built and its effectiveness is verified; the fluid domain is encrypted at multiple spatial scales; thus, the change of the fluid domain is obtained, small-scale modeling is carried out for places with large temperature field gradient changes, and large-scale modeling is carried out for other regions, and finally, each gradient model of the temperature field is obtained; finally, three-field coupling is carried out. The change rules of each field of the electromagnetic field, fluid field, and temperature field of the motor at different speeds are not fixed, so analysis and processing are carried out according to the situation of the fields and the specific problems to be studied, which can ensure accuracy and speed up the calculation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flowchart of a multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales according to the present invention;

[0043] Figure 2 is an overall modeling diagram of a multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales according to the present invention for a 6.5 MW-class induction motor;

[0044] Figure 3 is a schematic diagram of the hierarchical treatment of the rotor bars of a 6.5 MW-class induction motor using a multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the specific embodiments described are only a part of the embodiments of the present invention, rather than all of the specific embodiments. The components of the specific embodiments of the present invention usually described and shown in the drawings here can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0046] Therefore, the detailed description of the specific embodiments of the present invention provided in the accompanying drawings below is not intended to limit the scope of the claimed invention, but only represents the selected specific embodiments of the present invention. All other specific embodiments obtained by those skilled in the art based on the specific embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0047] To further understand the content, features and effects of the present invention, the following specific embodiments are exemplified and described in detail with reference to the accompanying Figures 1-3 as follows: Specific Embodiment 1:

[0049] A multi-field dynamic coupling modeling method for medium and large-sized motors based on multiple spatial scales, comprising the following steps:

[0050] S1. Determine the specific structure of the medium and large-sized motor and analyze the research problems. The specific structure is the cooling system, stator and rotor cores under the casing, and coils of the medium and large-sized motor, and the research problem analysis is electromagnetic performance and thermal performance;

[0051] S2. Determine the physical fields involved in the research problems in step S1. The physical fields include electromagnetic field, temperature field, and fluid field;

[0052] S3. Establish a two-dimensional electromagnetic field model and conduct validity verification;

[0053] Furthermore, the method for establishing the two-dimensional electromagnetic field model in step S3 includes the following steps:

[0054] S3.1. Perform small-scale modeling on the stator winding and rotor bar parts of the medium and large-sized motor. Conduct dense meshing on the stator winding and rotor bars. The meshing shape is triangular meshing, and the meshing setting value is 0.5 mm. Conduct meshing on the slot wedge insulation layer of the motor. The meshing shape is triangular meshing, and the meshing setting value is 0.1 mm; at the same time, layer the bars according to the bar embedding depth of the motor. The number of layers is selected from 10 to 15 layers. According to the skin effect, the meshing setting value of the 3-4 layers near the slot opening is 0.1 mm, and the meshing setting value of the remaining layered meshing is 0.5 mm;

[0055] S3.2. Perform large-scale modeling on the iron core and other components of the medium and large-sized motor. Conduct dense meshing on the iron core and other components. The meshing setting value is 1 mm, and the meshing shape is triangular meshing;

[0056] S3.3. Use finite elements to perform current element area integration to analyze the variation law of the losses of each layer of the motor bars during the dynamic process of the medium and large-sized motor;

[0057] S3.4. The core loss of the medium and large-sized motor is mainly concentrated in the stator teeth and stator yoke. The two parts are superimposed to obtain the calculation formula for the core loss as follows:

[0058]

[0059] In the formula: K d and K' d are the loss increase coefficients of the yoke and teeth respectively, G fej and G fetare the weights of the yoke and the gear respectively, and are the unit losses of the yoke and the tooth respectively, and B j and are the maximum magnetic flux density of the yoke and the tooth, respectively, N is the frequency. Since the electromagnetic gradient does not change much, its calculated result is taken as a constant value as the temperature rise heat source.

[0060] Furthermore, the finite element current surface integral is used to analyze the changing law of the loss of each layer of the motor conductor bar during the dynamic process of the motor to obtain an accurate loss value;

[0061] S4. Establish a fluid domain model based on multiple spatial scales and analyze the established fluid domain model;

[0062] Furthermore, the method of establishing the fluid domain model based on multiple spatial scales in step S4 includes the following steps:

[0063] S4.1. Divide the overall model into different regions according to the air flow direction and the complexity of each component structure:

[0064] S4.2. For medium and large motors, the stator and rotor cores have multiple radial ventilation ducts, and coils and bars pass through the middle, and the air flow is continuous, which serves as the core area;

[0065] S4.3, medium and large motors have a large number of stator winding slots, different winding methods, and complex end structures, which are used as end domains;

[0066] S4.4. According to the different cooling methods of medium and large motors, different areas are divided into blocks for processing;

[0067] S4.5. Small-scale modeling is performed in places where the fluid boundary layer gradient of medium and large motors is large, and it is divided into 0.5mm, and other areas are divided into 1mm;

[0068] S4.6. The fluid field changes of medium and large motors at different speeds are different. The stator and rotor laminar flow of medium and large motors are divided densely, and small-scale modeling is performed in the same way to obtain the fluid changes of medium and large motors at different speeds.

[0069] S4.7. At the end other than the fluid field, use it as a node of the fluid field for large-scale modeling;

[0070] S4.8. Simplify the parts that have little impact on the fluid field, including simplifying bearings, fans, and coolers;

[0071] S5. Establishing a temperature field gradient model;

[0072] Furthermore, step S5 of establishing the temperature field gradient model includes the following steps:

[0073] S5.1. For the stator winding part of medium and large motors, perform small-scale modeling with a triangular meshing and a meshing setting value of 0.5 mm. Mesh the slot wedge insulation layer of the motor with a triangular meshing and a meshing setting value of 0.1 mm;

[0074] S5.2. Stratify the rotor bar part of medium and large motors by the layering method. The calculation method for the layered current of the rotor bar part is as follows:

[0075] S5.2.1. Calculate the bar current value I of the motor at a certain moment by a computer finite element simulation software 总 ;

[0076] S5.2.2. Set the current value of the first layer in the rotor slot as x. Then the formula for the layered current of the rotor bar part is:

[0077]

[0078] where, are the currents of the i-th layer and the (i + 1)-th layer respectively, and R i , R i+1 are the DC resistances of the i-th layer and the (i + 1)-th layer respectively, and X i is the leakage reactance of the i-th layer;

[0079] X i = ωμl h i / b i

[0080] where, ω is the angular velocity, μ is the magnetic permeability, l is the length of the bar, h i is the height value of the i-th layer after bar layering, and b i is the width value of the i-th layer after bar layering. Thus, the current of the i-th layer is calculated. At this time, the currents of each layer are all functions of the current value of the first layer;

[0081] S5.2.3. Solve the system of equations with I 1 as the variable, and gradually deduce the proportion of the current of each layer of the bar in the total current value I 总 . Then multiply the actual bar current value I 总 by the proportion of the current of each layer of the bar to obtain the actual current value of each layer. Finally, observe the current value of each layer of the rotor bar, and obtain the skin effect degree in the rotor from the current distribution of the bar;

[0082] The above process is to perform small-scale modeling and analysis on the rotor bar, and further accurately grasp the temperature rise change law of the motor during starting, providing a certain reference value for the subsequent research of the motor under working conditions such as short-time peak working conditions and continuous working conditions;

[0083] S5.3. Conduct large-scale modeling on the stator and rotor cores of medium and large-sized motors.

[0084] S6. Establish a multi-field dynamic coupling model for medium and large-sized motors based on multiple spatial scales.

[0085] Furthermore, the multi-field dynamic coupling model for medium and large-sized motors established in step S6 includes unidirectional weak coupling, unidirectional strong coupling, bidirectional weak coupling, and bidirectional strong coupling.

[0086] Furthermore, perform refined meshing on the stator windings and rotor bars of a 6.5 MW large explosion-proof induction motor. The meshing setting value is 0.5 mm. At the same time, layer the bars. The overall height of the bars of the 6.5 MW induction motor is 50 mm, and each layer has a height of 1 / 10 to 1 / 15 of it; it is divided into 10 to 15 layers. Different meshing settings can also be performed for each layer to achieve the purpose of small-scale modeling. Use finite elements for current element area integration to obtain more accurate changes in motor loss values, laying a foundation for subsequent temperature field calculations. The schematic diagram of the modeling is as Figure 2 and Figure 3 shown.

[0087] It should be noted that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0088] Although the present application has been described above with reference to specific embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various features in the specific embodiments disclosed in the present application can be combined with each other in any way. The exhaustive description of these combinations is not given in this specification only for the sake of saving space and resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A multi-field dynamic coupling modeling method for medium and large-sized motors based on multi-space scales, characterized in that: It includes the following steps: S1. Determine the specific structure of the medium and large-sized motor and analyze the research problems. The specific structure is the cooling system, the stator and rotor cores under the casing, and the coils of the medium and large-sized motor. The research problem analysis is electromagnetic performance and thermal performance; S2. Determine the physical fields involved in the research problems in step S1. The physical fields include electromagnetic field, temperature field, and fluid field; S3. Establish a two-dimensional electromagnetic field model and conduct validity verification; The method for establishing the two-dimensional electromagnetic field model in step S3 includes the following steps: S3.

1. Perform small-scale modeling on the stator windings and rotor bars of the medium and large-sized motor, perform encrypted meshing on the stator windings and rotor bars. The meshing shape is triangular meshing, and the meshing setting value is 0.5 mm. Mesh the slot wedge insulation layer of the motor. The meshing shape is triangular meshing, and the meshing setting value is 0.1 mm; at the same time, layer the bars according to the embedding depth of the bars in the motor. The number of layers is selected from 10 to 15 layers. According to the skin effect, the meshing setting value of the 3-4 layers near the slot opening is 0.1 mm, and the meshing setting value of the remaining layered meshing is 0.5 mm; S3.

2. Perform large-scale modeling on the iron core and other components of the medium and large-sized motor, perform encrypted meshing on the iron core and other components. The meshing setting value is 1 mm, and the meshing shape is triangular meshing; S3.

3. Use finite element to perform current element area integration analysis to obtain the variation law of the loss of each layer of the motor bars during the dynamic process of the medium and large-sized motor; S3.

4. The iron core loss of the medium and large-sized motor is mainly concentrated in the stator teeth and stator yoke. The calculation formula for the iron core loss can be obtained by superimposing the two parts as follows: Where: K d and K' d are the loss increase coefficients of the yoke and teeth respectively, G fej and G fet are the weights of the yoke and teeth respectively, and are the specific losses of the yoke and teeth respectively, B j and are the maximum magnetic flux densities of the yoke and teeth respectively, f N is the frequency. Since the electromagnetic gradient changes little, the calculation result is taken as a constant value as the temperature rise heat source; S4. Establish a fluid domain model based on multi-space scales and analyze the established fluid domain model; S5. Establish a temperature field gradient model; S6. Establish a multi-field dynamic coupling model for medium and large-sized motors based on multi-space scales.

2. A multi-field dynamic coupling modeling method for medium and large-sized motors based on multi-space scales according to claim 1, characterized in that: The method for establishing a fluid domain model based on multi-space scales in step S4 includes the following steps: S4.

1. Divide the overall model according to the air flow direction and the complexity of the structure of each component: S4.

2. For medium and large-sized motors, the stator and rotor cores have multiple radial ventilation ducts, and there are coils and bars passing through in the middle. The air flow direction is continuous, which is used as the iron core domain; S4.

3. The stator windings of medium and large-sized motors have a large number of slots, different winding methods, and complex end structures, which are used as the end domain; S4.

4. Divide different regions for block processing according to different cooling methods of medium and large-sized motors; S4.

5. Perform small-scale modeling at places where the fluid boundary layer gradient of the medium and large-sized motor is large, and mesh it to 0.5 mm. Other regions are meshed according to 1 mm; S4.

6. Due to the different changes in the fluid field of the medium and large-sized motor at different speeds, perform encrypted meshing at the laminar flow of the stator and rotor of the medium and large-sized motor, and perform small-scale modeling in the same way to obtain the fluid changes of the medium and large-sized motor at different speeds; S4.

7. At the end other than the fluid field, use it as a node of the fluid field for large-scale modeling; S4.

8. Simplify the parts that have little impact on the fluid field, including simplifying bearings, fans, and coolers.

3. According to claim 1, a multi-field dynamic coupling modeling method for medium and large motors based on multiple spatial scales, Features: Step S5: Establishing the temperature field gradient model includes the following steps: S5.

1. For the stator winding part of medium and large motors, small-scale modeling is performed, the segmentation shape is triangular segmentation, and the segmentation setting value is 0.5mm. The slot wedge insulation layer of the motor is segmented, and the segmentation shape is triangular segmentation, and the segmentation setting value is 0.1mm; S5.

2. The rotor bar portion of medium and large motors is layered according to the layering method. The calculation method of the layered current of the rotor bar portion is: S5.2.

1. Calculate the bar current value I of the motor at a certain moment by a computer finite element simulation software 总 ; S5.2.

2. Set the current value of the first layer in the rotor slot to I 1 , then the formula for the stratified current of the rotor bar part is as follows: Among them, are the currents of the i-th layer and the (i + 1)-th layer of the rotor bar part respectively, and R i , R i+1 are the DC resistances of the i-th layer and the (i + 1)-th layer of the rotor bar part respectively, X i is the leakage reactance of the i-th layer of the rotor bar part, j is the imaginary unit, is the current value of each layer of the bar, and k is the layer number; X i = ωμl h i / b i where ω is the angular velocity, μ is the magnetic permeability, l is the length of the bar, and h i is the height value of the i-th layer after the bar is stratified, and b i is the width value of the i-th layer after the bar is stratified; the current of the i-th layer is calculated therefrom, and at this time, the currents of each layer are all functions of the current value of the first layer; S5.2.

3. Solve the system of equations with I 1 as the variable, and gradually deduce the proportion of the total current I 总 occupied by the currents of each layer of the bar. Then multiply the actual value I 总 of the bar current by the proportion of the currents of each layer of the bar to obtain the actual value of the current of each layer. Finally, observe the current value of each layer of the rotor bar, and obtain the degree of skin effect in the rotor from the current distribution of the bar; S5.

3. Perform large-scale modeling on the stator and rotor cores of medium and large motors.

4. According to claim 1, a multi-field dynamic coupling modeling method for medium and large motors based on multiple spatial scales, Features: Step S6 establishes a multi-field dynamic coupling model of medium and large motors based on multiple spatial scales, including unidirectional weak coupling, unidirectional strong coupling, bidirectional weak coupling, and bidirectional strong coupling.

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