Method, device and equipment for predicting crack propagation and dielectric property of motor slot outlet, and storage medium

Abstract

The application discloses a motor slot outlet crack propagation and dielectric performance prediction method, device, equipment and storage medium, relates to the motor insulation technical field, and the method comprises the steps of constructing a geometric model of a motor slot outlet, the geometric model comprising a stator core, a conductor and an insulator, and setting an initial electric potential field based on the voltage level of the stator core and the conductor; solving a mechanical displacement field and a phase field damage variable according to the material attribute parameters of the geometric model, and generating evolution trend data of a crack propagation path; calculating the electric damage variable and the electric field distortion data of the geometric model in the crack propagation process according to Poisson's equation, the initial electric potential field, the evolution trend data and the dielectric constant of the insulator; and obtaining a comprehensive prediction report containing a crack propagation path prediction graph and a dielectric performance degradation cloud chart according to the evolution trend data, the electric damage variable and the electric field distortion data. The application can accurately predict the motor slot outlet insulation crack propagation path and the dynamic change of dielectric performance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of motor insulation, in particular to a motor slot opening crack propagation and dielectric performance prediction method, device, equipment and storage medium. BACKGROUND

[0002] The insulation structure is widely used in the field of power equipment, and its performance directly affects the safe and stable operation of large motors. During the manufacturing, process treatment and long-term service of the main insulation, initial damage will inevitably occur in the main insulation layer of the stator end winding. At the same time, during the service of the large motor, the main insulation system will be subjected to complex multi-physical field actions such as magnetic, electric, thermal and mechanical coupling stress, resulting in an increase in internal crack defects of the main insulation and gradual evolution, thereby reducing the dielectric performance and residual breakdown voltage strength of the insulation, and even possibly causing insulation breakdown short circuit failure.

[0003] At present, for the prediction of motor insulation crack propagation and dielectric performance, the traditional method usually needs to define the crack path or track the crack tip in advance, and the influence of crack propagation on insulation performance is studied through experiments and finite element analysis.

[0004] However, the traditional method has complexity in crack path tracking, and it is difficult to accurately predict the bifurcation and propagation path of the crack. At the same time, these methods also have limitations in calculating the dielectric performance, and cannot dynamically reflect the change of the insulation performance in the crack propagation process. In addition, when the motor insulation is subjected to various mechanical stresses, the maximum stress position is usually at the slot opening of the motor end winding, and the existing method cannot accurately describe the influence of crack propagation in this area on the dielectric performance. Therefore, how to accurately predict the motor slot opening insulation crack propagation path and the dynamic change of the dielectric performance has become a problem to be solved.

[0005] The above content is only used to assist in understanding the technical solutions of the application and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0006] The application aims to provide a motor slot opening crack propagation and dielectric performance prediction method, device, equipment and storage medium, and aims to solve the technical problem of how to accurately predict the motor slot opening insulation crack propagation path and the dynamic change of the dielectric performance.

[0007] To achieve the above-mentioned purpose, the application provides a motor slot opening crack propagation and dielectric performance prediction method, which comprises the following steps:

[0008] A geometric model of the motor slot opening is constructed, the geometric model comprising a stator core, a conductor and an insulator, and an initial electric potential field is set based on the voltage level of the stator core and the conductor;

[0009] solving mechanical displacement field and phase field damage variable according to material attribute parameter of the geometric model, and generating evolution trend data of crack propagation path;

[0010] calculating electric damage variable and electric field distortion data of the geometric model during crack propagation according to Poisson equation, the initial electric potential field, the evolution trend data and dielectric constant of the insulator;

[0011] obtaining comprehensive prediction report including crack propagation path prediction map and dielectric performance degradation cloud atlas according to the evolution trend data, the electric damage variable and the electric field distortion data.

[0012] In an embodiment, the step of solving mechanical displacement field and phase field damage variable according to material attribute parameter of the geometric model, and generating evolution trend data of crack propagation path includes: calculating strain potential energy, fracture energy and external load potential energy of the insulator according to material attribute parameter of the geometric model; superimposing the strain potential energy, the fracture energy and the external load potential energy to generate weak form governing equation of total potential energy of the motor slot opening; iteratively solving mechanical displacement field and phase field damage variable based on the weak form governing equation, and generating evolution trend data of crack propagation path.

[0013] In an embodiment, the material attribute parameter includes elastic modulus, Poisson's ratio and fracture toughness parameter; the step of calculating strain potential energy, fracture energy and external load potential energy of the insulator according to material attribute parameter of the geometric model includes: calculating strain potential energy of the insulator by strain energy density function according to the elastic modulus and the Poisson's ratio; calculating fracture energy of the insulator according to the fracture toughness parameter and preset crack surface density function; calculating external load potential energy of the insulator according to amplitude, frequency and phase parameter of electromagnetic force suffered by the conductor in the geometric model.

[0014] In an embodiment, the step of iteratively solving mechanical displacement field and phase field damage variable based on the weak form governing equation, and generating evolution trend data of crack propagation path includes: discretizing the weak form governing equation into finite element equation; solving the finite element equation step by step in incremental loading mode to obtain mechanical displacement field and phase field damage variable; identifying crack propagation area according to numerical distribution of the phase field damage variable; determining crack propagation direction and crack propagation rate according to displacement gradient data of the mechanical displacement field; generating evolution trend data of crack propagation path according to the crack propagation area, the crack propagation direction and the crack propagation rate.

[0015] In an embodiment, the step of calculating the electric damage variable and the electric field distortion data of the geometric model during the crack propagation process according to the Poisson equation, the initial electric potential field, the evolution trend data and the dielectric constant of the insulator comprises: obtaining the initial dielectric constant distribution of the insulator from the geometric model; determining the crack area of the insulator according to the evolution trend data, and updating the dielectric constant of the crack area to the dielectric constant of air to obtain a target dielectric constant distribution; solving the Poisson equation according to the target dielectric constant distribution and the electric potential boundary condition of the initial electric potential field to obtain a dynamic electric potential distribution after the crack propagation; calculating the potential difference of each spatial point between the dynamic electric potential distribution and the initial electric potential field to obtain a potential distortion data set; performing normalization processing on the potential distortion data set according to a preset electric damage threshold to obtain the electric damage variable of the geometric model; performing gradient operation on the dynamic electric potential distribution to extract the electric field strength extreme value of the crack tip area to generate the electric field distortion data of the geometric model.

[0016] In an embodiment, the step of constructing the geometric model of the motor slot opening, the geometric model comprising a stator core, a conductor and an insulator comprises: establishing a three-dimensional geometric model of the stator core; disposing the conductor in the core slot part of the three-dimensional geometric model, and disposing the insulator between the conductor and the stator core; disposing the position, length and direction parameters of the initial crack on the insulator; after the insulator is disposed, disposing the material attribute parameters of the stator core and the conductor to complete the model construction.

[0017] In an embodiment, the step of obtaining the comprehensive prediction report containing the crack propagation path prediction graph and the dielectric performance degradation cloud chart according to the evolution trend data, the electric damage variable and the electric field distortion data comprises: converting the evolution trend data into a visualization chart, and labeling the crack length, bifurcation angle and propagation direction on the visualization chart to obtain the crack propagation path prediction graph; identifying the area where the dielectric constant attenuation exceeds the preset threshold through the color gradient mapping algorithm according to the spatial distribution data of the electric damage variable to generate the dielectric performance degradation cloud chart; labeling the high-risk breakdown area on the dielectric performance degradation cloud chart according to the electric field strength extreme value area in the electric field distortion data; after the high-risk breakdown area is labeled, superimposing the crack propagation path prediction graph and the dielectric performance degradation cloud chart in space to obtain the comprehensive prediction report.

[0018] In addition, in order to achieve the above-mentioned purpose, the application further provides a device for predicting crack propagation and dielectric performance of a motor slot opening, which comprises:

[0019] A model construction module is configured to construct a geometric model of a motor slot opening, the geometric model including a stator core, a conductor and an insulator, and set an initial electric potential field based on voltage levels of the stator core and the conductor;

[0020] A mechanical solution module is configured to solve a mechanical displacement field and a phase field damage variable according to material attribute parameters of the geometric model, and generate evolution trend data of a crack propagation path;

[0021] An electric field analysis module is configured to calculate an electric damage variable and an electric field distortion data of the geometric model in a crack propagation process according to Poisson equation, the initial electric potential field, the evolution trend data and a dielectric constant of the insulator;

[0022] A report generation module is configured to obtain a comprehensive prediction report including a crack propagation path prediction map and a dielectric performance degradation cloud map according to the evolution trend data, the electric damage variable and the electric field distortion data.

[0023] In addition, to achieve the above object, the present application further provides a motor slot opening crack propagation and dielectric performance prediction device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the computer program is configured to implement the steps of the motor slot opening crack propagation and dielectric performance prediction method as described above.

[0024] In addition, to achieve the above object, the present application further provides a storage medium, which is a computer readable storage medium, and the storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the motor slot opening crack propagation and dielectric performance prediction method as described above.

[0025] In addition, to achieve the above object, the present application further provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to implement the steps of the motor slot opening crack propagation and dielectric performance prediction method as described above.

[0026] The one or more technical solutions provided by the present application have at least the following technical effects:

[0027] Firstly, the simulation prediction system constructs a geometric model of the motor slot opening, including the stator core, conductor and insulator, and sets the initial potential field according to the voltage level of the stator core and conductor. This step ensures that the model can accurately simulate the actual structure and provide a reliable geometric basis for subsequent analysis. Next, the system solves the mechanical displacement field and phase field damage variable according to the material property parameters of the geometric model, generates evolution trend data of the crack propagation path, dynamically predicts the crack propagation path and branching situation through the phase field method, and improves the flexibility and accuracy of crack propagation prediction, providing a mechanical basis for crack propagation. Then, the system calculates the electrical damage variable and electric field distortion data of the geometric model during crack propagation according to Poisson's equation, the initial potential field, the evolution trend data and the dielectric constant of the insulator, quantifies the influence of crack propagation on the electrical properties of the insulator, and visually displays the electric field distortion situation to help identify high-risk breakdown areas. Finally, the system generates a comprehensive prediction report containing the crack propagation path prediction graph and dielectric performance degradation cloud chart based on the evolution trend data, electrical damage variable and electric field distortion data, integrates the crack propagation path and dielectric performance degradation situation together, provides a comprehensive evaluation reference, and provides an early warning of potential insulation fault points, providing an important basis for the design, fault diagnosis and repair of motor insulation structure, and accurately predicting the motor slot opening insulation crack propagation path and dielectric performance dynamic change. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application together with the specification.

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without creative labor.

[0030] Figure 1 A flowchart is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment one of the present application;

[0031] Figure 2 A motor slot opening structure diagram is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment one of the present application;

[0032] Figure 3 A two-dimensional equivalent model diagram of the slot opening insulation containing an initial crack is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment one of the present application;

[0033] Figure 4The insulator electric damage variable evolution schematic diagram is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment one of the application;

[0034] Figure 5 The insulator electric field distribution result schematic diagram is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment one of the application;

[0035] Figure 6 The different iteration insulator electric potential distribution schematic diagram is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment one of the application;

[0036] Figure 7 The electromechanical damage phase field model algorithm flowchart schematic diagram is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment one of the application;

[0037] Figure 8 The flowchart schematic diagram is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment two of the application;

[0038] Figure 9 The dynamic change schematic diagram of stress and strain near the sampling point in different regions is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment two of the application;

[0039] Figure 10 The insulator crack propagation state schematic diagram under different iteration step numbers is provided for the motor slot opening crack propagation and dielectric performance prediction method embodiment two of the application;

[0040] Figure 11 The module structure schematic diagram of the motor slot opening crack propagation and dielectric performance prediction device of the embodiment of the application is provided;

[0041] Figure 12 The device structure schematic diagram of the hardware running environment involved in the motor slot opening crack propagation and dielectric performance prediction method in the embodiment of the application is provided.

[0042] The purpose realization, function characteristics and advantages of the application will be further explained by combining with the embodiments and referring to the drawings. DETAILED DESCRIPTION

[0043] It should be understood that the specific embodiments described herein are merely intended to explain the technical solutions of the application, and not to limit the application.

[0044] In order to better understand the technical solutions of the application, the following will be described in detail by combining with the drawings and specific embodiments in the specification.

[0045] The insulation structure is widely used in power equipment, and its performance is crucial to the safe and stable operation of large motors. During manufacturing, processing and service, the main insulation layer of the stator end winding is prone to initial damage, and under the action of complex physical fields, internal cracks will increase and evolve, leading to a decrease in dielectric performance and even causing insulation breakdown and short circuit failure. The existing prediction methods require pre-defined crack paths or tracking of crack tips, which have complexity and limitations, and cannot dynamically reflect the impact of crack propagation on dielectric performance, especially in the most stressed slot exit area.

[0046] The main solution of the embodiment of the present application is: first, a motor slot exit geometric model containing a stator core, a conductor and an insulator is constructed, and an initial potential field is set according to the voltage level to provide an accurate geometric basis for subsequent analysis. Next, the material attribute parameters are used to solve the mechanical displacement field and the phase field damage variable to generate evolution trend data of the crack propagation path, dynamically predict the crack propagation path, and improve the flexibility and accuracy of the prediction. Then, the electric damage variable and the electric field distortion data in the crack propagation process are calculated through the Poisson equation and related parameters to quantify the impact on the electric performance and intuitively display the electric field distortion. Finally, a comprehensive prediction report containing the crack propagation path prediction graph and the dielectric performance degradation cloud chart is generated to provide a comprehensive reference for the evaluation of the motor insulation structure.

[0047] It should be noted that the execution subject of the embodiment of the present application can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an electronic device, a simulation prediction system, etc. capable of realizing the above functions. The simulation prediction system is taken as an example to illustrate the embodiment and the following embodiments.

[0048] Based on this, the embodiment of the present application provides a motor slot exit crack propagation and dielectric performance prediction method, which refers to Figure 1 , Figure 1 The flowchart of the first embodiment of the motor slot exit crack propagation and dielectric performance prediction method of the present application is shown in the figure.

[0049] In the embodiment, the motor slot exit crack propagation and dielectric performance prediction method includes steps S10-S40:

[0050] Step S10, a geometric model of the motor slot exit is constructed, the geometric model includes a stator core, a conductor and an insulator, and an initial electric potential field is set based on the voltage level of the stator core and the conductor.

[0051] It should be noted that the motor slot exit refers to the slot exit position of the motor end winding, which is the area with the largest stress, most prone to mechanical damage and crack propagation in the motor insulation structure.

[0052] The geometric model refers to a mathematical abstraction and simplification of the physical structure of the motor slot opening area, including the shapes, sizes, and relative positional relationships of the stator core, conductors, and insulators.

[0053] The stator core is one of the main components of the motor stator, usually made of silicon steel sheets, used to form the magnetic circuit of the motor. In the geometric model of the motor slot opening, the shape and size of the stator core will affect the mechanical and electromagnetic properties of the insulation structure.

[0054] The conductor refers to the conductive part of the motor winding, usually made of conductive materials such as copper or aluminum. In the geometric model of the motor slot opening, the position and shape of the conductor will affect the electromagnetic field distribution and mechanical stress distribution, and thus affect the performance of the insulation structure.

[0055] The insulator refers to the insulating material used to isolate the conductor and the stator core, preventing electrical short circuits, such as epoxy resin and mica tape. Damage and crack propagation of the insulator will lead to a decrease in dielectric properties, which may eventually cause an insulation breakdown short circuit failure.

[0056] The voltage level refers to the voltage size that the motor can withstand, usually measured in volts (V). Different voltage levels will result in different electric field distributions and electrical stresses, affecting the dielectric properties and crack propagation path of the insulator.

[0057] The initial potential field refers to the potential distribution set according to the voltage level and geometric model of the motor before crack propagation and dielectric property prediction, reflecting the potential distribution state of the motor without cracks.

[0058] Please refer to Figure 2 , Figure 2 The motor slot opening structure diagram provided for the first embodiment of the method for predicting the crack propagation and dielectric properties of the motor slot opening of the present application is shown in the figure, in which the end winding is composed of copper wires and is wrapped by insulating materials. As can be seen from the figure, there are obvious crack defects in the insulating materials, which may further expand during the operation of the motor, leading to a decrease in insulation performance. The enlarged view on the right side details the mutual relationship between the copper wire, the insulating layer, and the stator core. The crack defect is located in the insulating layer and may intensify the expansion under the action of dynamic electromagnetic force. The integrity of this structure is crucial for the safe operation of the motor, as the expansion of the crack may lead to insulation breakdown and thus cause a short circuit failure.

[0059] It can be understood that first, the simulation prediction system constructs a geometric model containing the stator core, the conductor and the insulator according to the actual structural parameters of the motor slot opening, ensures that the model can truly reflect the physical structure of the motor slot opening and the relative position relationship of each component, and provides an accurate geometric basis for subsequent analysis. Secondly, the system calculates and sets the initial potential field according to the voltage level of the stator core and the conductor, combined with the working conditions of the motor and the electrical properties of the insulating material. Specifically, the system will apply a potential value corresponding to the actual working voltage on the conductor, while grounding the stator core (setting it to zero potential), to simulate the potential distribution of the motor under normal working conditions.

[0060] As an example, the step of constructing a geometric model of the motor slot opening, the geometric model including a stator core, a conductor and an insulator, includes: establishing a three-dimensional geometric model of the stator core; setting the conductor in the core slot part of the three-dimensional geometric model, and setting the insulator between the conductor and the stator core; setting the position, length and direction parameters of the initial crack on the insulator; after the insulator is set, setting the material attribute parameters of the stator core and the conductor, completing the model construction.

[0061] The core slot part is the part of the stator core used to place the conductor, usually in a slot-shaped structure, and is the key area for setting the conductor and the insulator. Its shape and size determine the arrangement of the conductor and the distribution of the insulator, and further affect the prediction results of crack propagation and dielectric performance.

[0062] The initial crack refers to the pre-set crack morphology in the motor slot opening insulating structure, which represents the initial damage state that may occur in the manufacturing, process treatment or service process of the insulating structure. When constructing the geometric model, the initial crack is specifically set on the insulator to simulate the possible small cracks or defects in the actual insulating structure. These cracks serve as the starting point in the subsequent crack propagation analysis, and their position, length and direction will affect the crack propagation path and speed, and further affect the dielectric and mechanical properties of the insulating structure.

[0063] Please refer to Figure 3 , Figure 3The two-dimensional equivalent model of the slot outlet insulation containing initial cracks provided in Embodiment One of the method for predicting the slot outlet crack propagation and dielectric performance of the motor of the present application is a two-dimensional plane structure in which the stator core and the conductor are simplified. The insulation layer, the potential distribution, the potential boundary (10kV), the dynamic electromagnetic force, and the position of the crack defect are identified in the figure. The insulation layer is located between the conductor and the stator core, and plays a role in isolating the current and protecting the safe operation of the motor. The potential distribution shows the potential change on the insulation layer, and the potential boundary represents the voltage level during the operation of the motor. The dynamic electromagnetic force is the force on the conductor due to the electromagnetic field generated during the operation of the motor, which may cause stress concentration and crack propagation of the insulation layer. The defects in the figure represent the initial cracks in the insulation layer, which may further propagate under the combined action of electromagnetic force and mechanical stress, affecting the dielectric performance of the motor.

[0064] The material attribute parameters are physical and mechanical characteristic parameters of the materials such as the stator core, the conductor and the insulation, and by setting these parameters, it can be ensured that the prediction model can accurately reflect the physical behavior and mechanical performance of the actual materials.

[0065] Firstly, the simulation prediction system constructs a three-dimensional geometric model of the stator core through three-dimensional modeling technology, ensures that its shape and size are consistent with the stator core in the actual motor, and provides a basic framework for subsequent structure setting. Then, in the core slot part of the three-dimensional geometric model, the position and size of the conductor are set according to the design requirements of the actual motor, and the insulation is filled between the conductor and the stator core to form a complete motor slot outlet structure. Then, according to the actual possible damage, the position, length and direction parameters of the initial cracks are set on the insulation, which will serve as the starting point for crack propagation analysis. Finally, after the insulation is set, the material attribute parameters of the stator core and the conductor are set according to the characteristics of the actual materials, ensuring that the model can accurately reflect the physical and mechanical behavior of the materials, thereby completing the construction of the entire model and preparing for subsequent crack propagation and dielectric performance prediction analysis.

[0066] In step S20, the mechanical displacement field and the phase field damage variable are solved according to the material attribute parameters of the geometric model, and the evolution trend data of the crack propagation path are generated.

[0067] It should be noted that the mechanical displacement field refers to the change in the position of each point in the geometric model of the motor slot outlet due to the action of external forces (such as electromagnetic force, mechanical stress, etc.), which reflects the deformation of the insulation, conductor and stator core after being subjected to force.

[0068] The phase field damage variable is a variable used in the phase field method to describe the degree of material damage. It is used to quantify the damage state inside the insulator, including the formation, propagation and distribution of cracks. The value of the phase field damage variable is usually between 0 and 1, with 0 indicating that the material is not damaged and 1 indicating that the material is completely broken. By solving the phase field equation, the distribution of the phase field damage variable can be obtained, thus dynamically describing the propagation process of the crack and the evolution of the damage.

[0069] The crack propagation path refers to the trajectory of the crack from the initial position to the final position in the motor slot opening insulation structure.

[0070] The evolution trend data refers to the dynamic data of the crack position, length, direction and phase field damage variable changing with time during the crack propagation process. These data reflect the entire evolution process of the crack from the initial state to the final state, including the bifurcation of the crack and the change of the propagation direction. By generating these evolution trend data, the state of the crack at different time points can be predicted, providing important reference for the design, fault diagnosis and repair of the motor insulation structure.

[0071] It can be understood that first, the simulation prediction system solves the mechanical displacement field according to the material property parameters of each part in the geometric model, determines the displacement of each point in the model after being subjected to force, and provides a mechanical basis for crack propagation. Second, the system solves the phase field damage variable based on the phase field theory and the material fracture energy, dynamically describes the damage distribution inside the insulator and the formation and development of the crack. Finally, by analyzing the change of the phase field damage variable, the crack propagation path and bifurcation are predicted, the evolution trend data of the crack propagation path is generated, and the dynamic information such as the position, length and direction of the crack at different time points is recorded, which provides an important basis for the subsequent dielectric performance analysis and reliability evaluation of the insulation structure.

[0072] Step S30, according to the Poisson equation, the initial electric potential field, the evolution trend data and the dielectric constant of the insulator, the electric damage variable and the electric field distortion data of the geometric model in the crack propagation process are calculated.

[0073] It should be noted that the dielectric constant refers to the ability of an insulating material to store electric energy under the action of an electric field, which is an electrical property parameter of the material. In this embodiment, the dielectric constant is used to describe the polarization degree of the insulator (such as epoxy resin and mica tape) in the electric field. Different insulating materials have different dielectric constants, which directly affect the distribution and strength of the electric field. By setting the dielectric constant of the insulator, the propagation and distribution of the electric field in the insulator can be accurately calculated, providing a basis for the calculation of the electric damage variable.

[0074] The electrical damage variable is used to quantify the degree of deterioration of the electrical performance of the insulator during crack propagation, reflecting the influence of crack propagation on the electrical performance of the insulator, including changes in potential distribution, increases in electric field strength, etc. By calculating the electrical damage variable, the negative impact of crack propagation on the dielectric properties of the insulator can be evaluated, providing an important basis for the reliability assessment of the insulating structure. This variable is quantitatively described by s(r):

[0075]

[0076] where V0(r) is the initial potential, V t (r) is the deteriorated potential, and r is the coordinate vector.

[0077] Please refer to Figure 4 , Figure 4 The insulator electrical damage variable evolution diagram provided by the first embodiment of the present application for predicting the crack propagation and dielectric performance of the motor slot opening shows the evolution process of the insulator electrical damage variable S with the increase of the iteration step number. The dynamic change of the electrical damage degree inside the insulator is clearly presented through color mapping. The color in the figure changes from black (no damage, S = 0) to yellow (complete damage, S = 1), reflecting the damage state of the insulator at different iteration step numbers. From the initial state at iteration step number 0 (Figure a) to the final state at iteration step number 1500 (Figure f), it can be observed that the damage area gradually expands, and the color transitions from local red (moderate damage) to yellow, indicating that the damage degree of the insulator is continuously aggravated over time and under the continuous action of external load. Especially near the crack tip, the electrical damage variable grows significantly, which is consistent with the action of dynamic electromagnetic force and the crack propagation path. This series of figures intuitively reveals the electrical damage evolution mechanism of the insulator under the combined action of electromagnetic force and mechanical stress, providing an important basis for evaluating the reliability and life of the motor insulating structure.

[0078] The electric field distortion data refers to the specific data of the change in electric field distribution during crack propagation, reflecting the influence of crack propagation on the electric field distribution. Specifically, the electric field distortion data includes changes in electric field strength, changes in electric field direction, and concentration of electric field near the crack. These data can directly show the disturbance of crack propagation on the electric field distribution, helping to analyze the influence of crack propagation on the dielectric properties of the insulator, and providing a reference for the design and optimization of the insulating structure.

[0079] It can be understood that first, the system calculates the electric field distribution of the geometric model without cracks based on the initial electric potential field and the dielectric constant of the insulator using the Poisson equation, providing a benchmark for subsequent analysis. Then, combined with the evolution trend data of the crack propagation path, the system dynamically adjusts the electric field distribution to simulate the influence of crack propagation on the electric field. Then, by comparing the electric field distribution before and after crack propagation, the electric damage variable is calculated to quantify the degree of electrical performance degradation caused by crack propagation. Finally, the system records the distortion of the electric field near the crack and generates electric field distortion data to intuitively reflect the disturbance of the crack on the electric field distribution, providing an important basis for the reliability assessment of the insulating structure.

[0080] Please refer to Figure 5 , Figure 5 The figure shows the electric field distribution results of the insulating layer provided by the first embodiment of the method for predicting the slot crack propagation and dielectric performance of the motor. Each subgraph corresponds to a different iteration step, from (a) iteration step = 0 to (f) iteration step = 1500, reflecting the changes in the electric field distribution of the insulating layer during the crack propagation process. The arrows in the figure represent the direction of the electric field, and the density and length of the arrows represent the size of the electric field strength. As the iteration step increases, it can be seen that the electric field strength near the crack region increases significantly, and the arrows become more dense and longer, indicating that crack propagation causes electric field distortion in this region. This electric field distortion may further accelerate the propagation of the crack and affect the performance of the insulating layer. The x and y axes in the figure represent the spatial position of the insulating layer, and the crack starts to propagate from the initial position. As the iteration step increases, the crack path gradually becomes clear, and the electric field distribution also changes accordingly. These images intuitively demonstrate the dynamic evolution process of the electric field in the insulating layer during crack propagation, providing an important basis for predicting the reliability and life of the motor insulation.

[0081] As an example, the step of calculating the electric damage variable and the electric field distortion data of the geometric model during crack propagation according to the Poisson equation, the initial electric potential field, the evolution trend data, and the dielectric constant of the insulator includes: obtaining the initial dielectric constant distribution of the insulator from the geometric model; determining the crack region of the insulator according to the evolution trend data, and updating the dielectric constant of the crack region to the air dielectric constant to obtain a target dielectric constant distribution; solving the Poisson equation according to the target dielectric constant distribution and the electric potential boundary condition of the initial electric potential field to obtain a dynamic electric potential distribution after crack propagation; calculating the potential difference between the dynamic electric potential distribution and the initial electric potential field at each spatial point to obtain a potential distortion data set; normalizing the potential distortion data set according to a preset electric damage threshold to obtain the electric damage variable of the geometric model; performing gradient operation on the dynamic electric potential distribution to extract the electric field strength extreme value of the crack tip region, and generating the electric field distortion data of the geometric model.

[0082] The initial dielectric constant distribution refers to the spatial distribution of the dielectric constant of different parts of an insulator in a geometric model before crack propagation occurs, reflecting the electrical characteristics of the insulator in its initial state.

[0083] A cracked region refers to the portion of an insulator where a crack has formed during crack propagation. The location, length, and direction of the crack can be determined based on evolution trend data, thus defining the extent of the cracked region. In calculations, the dielectric constant of the cracked region needs to be updated to reflect the impact of the crack on the electrical properties of the insulator. The air dielectric constant is the dielectric constant of air, typically taken as 1 (the dielectric constant of air in a vacuum is 1, and its value is close to that of a vacuum). In the cracked region, because the insulating material is damaged, the crack is usually filled with air; therefore, the dielectric constant of the cracked region is updated to the air dielectric constant.

[0084] The target dielectric constant distribution refers to the final distribution of the dielectric constant of the insulator in the geometric model after considering crack propagation.

[0085] Potential boundary conditions refer to the potential values ​​at the boundaries of the geometric model when solving the Poisson equation. In this embodiment, they typically include the potential values ​​on the conductors and the ground potential (zero potential) of the stator core.

[0086] Dynamic potential distribution refers to the distribution of electric potential at various points in a geometric model over time during crack propagation. Compared to the initial potential field, it can more accurately describe the electric field environment after crack propagation. The Poisson equation is used to calculate the changes in electric potential and electric field on the insulator during crack propagation:

[0087]

[0088] Where r is the position vector in space, ρ is the charge density function (taken as a constant), D is the electric flux density, E is the electric field strength, and ε0 and ε(r) are the dielectric constants of air and insulation, respectively. The Laplace operator represents the derivative of the electric potential in the x and y directions.

[0089] Please refer to Figure 6 , Figure 6The different iteration insulation potential distribution diagrams provided by Embodiment One of the method for predicting the slot port crack propagation and dielectric properties of the motor of the present application reflect the changes in the potential of the insulation layer during the crack propagation process. Each sub-diagram in the figure corresponds to a different iteration step number, from (a) iteration step number = 0 to (f) iteration step number = 1500, and the potential distribution gradually evolves from the initial state. In each sub-diagram, the potential value is in volts (V) and changes along the z-axis direction, with the color gradually changing from blue (low potential) to yellow (high potential). As the iteration step number increases, it can be seen that the potential distribution near the crack region changes significantly, and the potential gradient increases, indicating that crack propagation leads to distortion of the electric field in this region. In particular, in sub-diagram (c), the crack region is clearly identified, showing local changes in potential. These images intuitively demonstrate the dynamic evolution of the potential of the insulation layer during crack propagation, providing an important basis for predicting the reliability and life of the motor insulation. By analyzing the potential distribution at different iteration steps, the impact of crack propagation on insulation performance can be evaluated, providing guidance for motor insulation design and fault diagnosis.

[0090] The potential distortion data set refers to the set of potential differences between the potential of each point in the geometric model during crack propagation and the initial potential field, which reflects the degree of disturbance of crack propagation on the potential distribution.

[0091] The pre-set electrical damage threshold refers to a reference value for normalization processing when calculating the electrical damage variable.

[0092] The crack tip region refers to the region near the end of the crack, usually referring to the front end portion in the direction of crack propagation, which is the area with the most significant change in electric field intensity and is the area most susceptible to electric field distortion.

[0093] The electric field intensity extremum refers to the maximum value of the electric field intensity in the crack tip region, reflecting the degree of electric field distortion in the crack tip region, and is an important indicator for evaluating the electrical damage of the insulator.

[0094] Firstly, the simulation prediction system extracts the initial permittivity distribution data of each part of the insulator from the constructed geometric model. These data reflect the electrical characteristics of the insulator in the undamaged state, providing basic parameters for subsequent electric field calculations. Secondly, the system accurately determines the location, length, and direction of the crack in the insulator based on the evolution trend data of the crack propagation path, and clearly defines the crack area. Then, the system updates the permittivity of the crack area to the permittivity of air, as the crack is usually filled with air. This update operation enables the model to more accurately reflect the actual impact of the crack on the electric field distribution, thereby obtaining the target permittivity distribution. Next, the system combines the target permittivity distribution and the potential boundary conditions of the initial potential field, and uses the finite element analysis method to solve the Poisson equation to calculate the dynamic potential distribution of each point in the geometric model after the crack propagation. This step is to obtain the specific impact of crack propagation on the potential distribution. After that, the system generates a potential distortion data set by calculating the potential difference between the dynamic potential distribution and the initial potential field at each spatial point. This data set directly shows the changes in potential distribution caused by crack propagation. Further, the system normalizes the potential distortion data set according to the pre-set electrical damage threshold to obtain the electrical damage variable of the geometric model. This processing process is to standardize the potential distortion data in order to more accurately quantify the degree of electrical performance degradation caused by crack propagation. Finally, the system performs gradient operation on the dynamic potential distribution, extracts the electric field strength extreme value of the crack tip region according to the electric field strength calculation formula, and generates the electric field distortion data of the geometric model. This step is to directly show the distortion of the electric field in the crack tip region, as the crack tip is usually the most significant area of electric field distortion. These data provide important basis for the reliability assessment of the insulating structure.

[0095] Step S40, according to the evolution trend data, the electrical damage variable and the electric field distortion data, a comprehensive prediction report containing crack propagation path prediction map and dielectric performance degradation cloud chart is obtained.

[0096] It should be noted that the crack propagation path prediction map refers to the graph generated by the simulation prediction system, which shows the path of the crack gradually expanding from the initial position over time and under the action of external force.

[0097] The dielectric performance degradation cloud chart refers to the graph generated by the simulation prediction system, which shows the degree of dielectric performance degradation at different positions of the insulator during the crack propagation process. It can clearly show the impact of crack propagation on the dielectric performance of the insulator, especially the electric field distortion and electrical damage in the crack tip region, providing important basis for the optimization design and fault diagnosis of the insulating structure.

[0098] The comprehensive prediction report refers to the report integrating the crack propagation path prediction map and the dielectric performance degradation cloud chart. This report not only contains the path information of crack propagation, but also shows the influence of crack propagation on the dielectric performance of the insulator. The comprehensive prediction report comprehensively shows the mechanical and electrical behaviors in the crack propagation process through graphs and data.

[0099] It can be understood that, first, the simulation prediction system draws a crack propagation path prediction map using the evolution trend data, visually presents the extension direction, length and bifurcation of the crack starting from the initial position, and intuitively presents the dynamic expansion process of the crack. Then, the system generates a dielectric performance degradation cloud chart according to the electrical damage variable and the electric field distortion data, and represents the electrical damage degree and the electric field distortion at different positions in the form of color or contour line, clearly reflecting the influence of crack propagation on the dielectric performance of the insulator. Finally, the crack propagation path prediction map and the dielectric performance degradation cloud chart are integrated to form a comprehensive prediction report, which provides a comprehensive and intuitive reference for the design, fault diagnosis and repair of the motor insulating structure.

[0100] Please refer to Figure 7 , Figure 7 The figure describes the calculation process from the initial state to the damage evolution. In the figure, d represents the initial damage state, u represents the displacement field (mechanical displacement field), V / E represents the ratio of electric potential energy to elastic energy, and s represents the electrical damage variable. The process starts from the initial state, iteratively calculates the displacement field u n and the damage field d n (the electrical damage variable is a specific type of damage field, which is used to describe the damage of the material under the action of the electric field. The damage field is a more general concept, which can be used to describe the damage or degradation of the internal structure and performance of the material after being subjected to various forms of stress (such as mechanical stress, thermal stress, chemical corrosion, etc.). The damage field is usually a continuous field, which represents the damage degree of each point in the material, and the damage degree can be represented by a scalar value, which is usually between 0 and 1, where 0 represents no damage and 1 represents complete fracture or failure.), and updates u n and d n+1 at each time step t n+1 . In this process, the phase field d and the mechanical field u are coupled to form a fracture phase field model, and then the crack propagation state at different time steps is calculated. The algorithm considers the changes of the electric potential field / electric field, calculates the changes of the electric potential and electric field on the insulator during crack propagation through the Poisson equation, and defines the electrical damage variable to quantitatively describe the degradation degree of the electrical performance of the insulator. Finally, the process generates a comprehensive prediction report containing a crack propagation path prediction map and a dielectric performance degradation cloud chart, which provides important information for the reliability evaluation of the motor insulating structure.

[0101] As an example, the step of obtaining a comprehensive prediction report including a crack propagation path prediction map and a dielectric performance degradation cloud map based on the evolution trend data, the electrical damage variable, and the electric field distortion data includes: converting the evolution trend data into a visualization chart and marking the crack length, branching angle, and propagation direction on the visualization chart to obtain a crack propagation path prediction map; identifying the area where the dielectric constant decay exceeds a preset threshold value through a color gradient mapping algorithm based on the spatial distribution data of the electrical damage variable to generate a dielectric performance degradation cloud map; marking the high-risk breakdown area on the dielectric performance degradation cloud map according to the electric field strength extreme value area in the electric field distortion data; and superimposing the crack propagation path prediction map and the dielectric performance degradation cloud map in space to obtain a comprehensive prediction report after marking the high-risk breakdown area.

[0102] Visualization chart refers to displaying complex numerical data or calculation results in the form of graphics for intuitive understanding and analysis.

[0103] Branching angle refers to the included angle formed by the branching of the crack during the propagation process.

[0104] Propagation direction refers to the main direction followed by the crack during the propagation process, the movement trajectory of the crack from the initial position to the final position, reflecting the main propagation path of the crack under the influence of stress and material properties.

[0105] Spatial distribution data refers to the specific location and numerical distribution of the electrical damage variable in the geometric model, reflecting the degree of electrical damage at different locations, usually stored in the form of grids or nodes, and the electrical damage variable value at each location is used for subsequent color mapping.

[0106] Color gradient mapping algorithm is an algorithm that maps numerical data to a color range. When generating a dielectric performance degradation cloud map, this algorithm maps different numerical ranges to different colors according to the spatial distribution data of the electrical damage variable, so that the change in electrical damage degree is visually represented by the change in color. Color gradient mapping algorithm can enhance the visual effect and make the cloud map clearer and easier to understand.

[0107] Preset threshold refers to a reference value set in advance when analyzing the electrical damage variable, used to identify areas where the dielectric constant decay exceeds this value, which are usually the parts with more serious electrical damage.

[0108] Electric field strength extreme value area refers to the area where the electric field strength reaches the maximum or extreme value in the electric field distortion data. These areas are usually near the crack tip where the electric field distortion is most significant.

[0109] The high-risk breakdown region refers to the region with the maximum electric field intensity and high electric damage variable on the dielectric performance degradation cloud chart. These regions are more prone to insulation breakdown failure due to high electric field intensity and severe electric damage.

[0110] First, the simulation prediction system extracts the dynamic information of the crack from the evolution trend data, including the length, branching angle, and propagation direction of the crack at different time steps. These information is plotted on a two-dimensional or three-dimensional chart to form a crack propagation path prediction chart. The system marks the length, branching angle, and propagation direction of the crack on the chart with different colors or line styles to visually display the dynamic change process of the crack. Second, the system generates a dielectric performance degradation cloud chart using a color gradient mapping algorithm based on the spatial distribution data of the electric damage variable. Specifically, the system divides the numerical range of the electric damage variable into multiple intervals, each interval corresponding to a color. For example, lower electric damage variable values may be mapped to green, indicating good dielectric performance, and higher electric damage variable values may be mapped to red, indicating severe dielectric performance degradation. The system traverses each node or grid cell in the geometric model and assigns the corresponding color based on its electric damage variable value, ultimately generating a dielectric performance degradation cloud chart. The spatial distribution of the electric damage variable is visually displayed through the color change, helping engineers quickly identify areas of dielectric performance degradation.

[0111] Then, the system marks the high-risk breakdown region on the dielectric performance degradation cloud chart based on the electric field intensity maximum region in the electric field distortion data. The system first identifies the region where the electric field intensity exceeds the preset threshold, which is usually near the crack tip where the electric field distortion is most significant. The system marks these high-risk breakdown regions on the dielectric performance degradation cloud chart with specific colors or symbols to allow engineers to quickly identify potential insulation failure points. Finally, after marking the high-risk breakdown region, the system spatially superimposes the crack propagation path prediction chart and the dielectric performance degradation cloud chart. Specifically, the system aligns the two charts to ensure they are consistent in spatial position. The system displays the crack propagation path and dielectric performance degradation in the superimposed chart, with the crack propagation path displayed as a line and the dielectric performance degradation displayed as a color cloud chart. The purpose of this step is to provide a comprehensive view that allows engineers to view the crack propagation path and dielectric performance degradation simultaneously, thereby more comprehensively evaluating the reliability and safety of the insulation structure and providing important basis for the design, fault diagnosis, and repair of the motor insulation structure.

[0112] The embodiment provides a motor slot outlet crack propagation and dielectric performance prediction method, first, a simulation prediction system constructs a geometric model of a motor slot outlet, including a stator core, a conductor and an insulator, and sets an initial potential field according to the voltage level of the stator core and the conductor, which ensures that the model can accurately simulate the actual structure and provides a reliable geometric basis for subsequent analysis. Then, the system solves the mechanical displacement field and the phase field damage variable according to the material attribute parameters of the geometric model, generates evolution trend data of the crack propagation path, dynamically predicts the crack propagation path and bifurcation through the phase field method, improves the flexibility and accuracy of crack propagation prediction, and provides a mechanical basis for crack propagation. Then, the system calculates the electric damage variable and the electric field distortion data of the geometric model in the crack propagation process according to the Poisson equation, the initial potential field, the evolution trend data and the dielectric constant of the insulator, quantifies the influence of crack propagation on the electric performance of the insulator, intuitively displays the electric field distortion situation, and helps to identify the high-risk breakdown area. Finally, the system generates a comprehensive prediction report containing the crack propagation path prediction graph and the dielectric performance degradation cloud chart according to the evolution trend data, the electric damage variable and the electric field distortion data, integrates the crack propagation path and the dielectric performance degradation together, provides a comprehensive evaluation reference, and early warns potential insulation fault points, provides an important basis for the design, fault diagnosis and repair of the motor insulation structure, and can accurately predict the motor slot outlet insulation crack propagation path and the dynamic change of dielectric performance.

[0113] Based on the first embodiment of the application, the same or similar contents as the above-mentioned embodiment one can refer to the above introduction, and the following will not be repeated. On this basis, please refer to Figure 8 , Figure 8 The flowchart of the second embodiment of the motor slot outlet crack propagation and dielectric performance prediction method of the application is shown in the figure, and the steps Sx0 of the motor slot outlet crack propagation and dielectric performance prediction method include steps S21-S23.

[0114] Step S21, calculating the strain potential energy, fracture energy and external load potential energy of the insulator according to the material attribute parameters of the geometric model.

[0115] It should be noted that the strain potential energy refers to the energy stored by the insulator in the process of force deformation, which is part of the total potential energy of the system, and is used to describe the energy state of the insulator under mechanical load.

[0116] Please refer to Figure 9 , Figure 9The dynamic stress and strain changes around different sampling points in different regions for the second embodiment of the method for predicting slot notch crack propagation and dielectric properties of the motor of the present application are shown in the schematic diagram. The upper graph shows the strain changes (in inches) of three sampling points (A, B, C), and the lower graph shows the corresponding stress changes (in MPa). As can be seen from the diagram, the strain and stress changes of sampling point B are the most significant, showing obvious periodic fluctuations. This may be due to the fact that this point is located on the crack propagation path and is subjected to the combined action of dynamic electromagnetic force and mechanical load. In contrast, the changes of sampling points A and C are smaller, indicating that the damage in these regions is lower. As the number of iteration steps increases, the stress and strain fluctuation amplitude of sampling point B gradually decreases, which may be due to the fact that the material gradually adapts to the load, or the stress concentration area changes due to crack propagation. These dynamic change data are of great significance for understanding the mechanical behavior and damage evolution of the motor insulation structure during operation, and are helpful for predicting the crack propagation path and evaluating the degradation of insulation performance.

[0117] The fracture energy refers to the energy released by the material during the fracture process, and is usually used to describe the fracture toughness of the material. In this embodiment, the fracture energy G c is a key parameter for judging the critical condition of crack propagation, reflecting the energy required for material fracture during crack propagation. The fracture energy is part of the total potential energy of the system, and is used to describe the energy change during crack propagation.

[0118] The external load potential energy refers to the potential energy possessed by the external force (such as electromagnetic force, mechanical force, etc.) acting on the insulation. In this embodiment, the external load potential energy W ext is calculated by the product of external force F and displacement u. The external load potential energy reflects the effect of external force on the insulation, and is part of the total potential energy of the system, used to describe the influence of external force on the energy state of the system.

[0119] The total potential energy of the system inside the slot insulation:

[0120] W = W b + W d - W ext

[0121] where W b is the insulation strain potential energy, W ext is the external force potential energy, and W d is the fracture energy.

[0122] It can be understood that firstly, the simulation prediction system calculates the strain potential energy of the insulator according to the material property parameters in the geometric model, by using the strain energy density function and the strain, which reflects the energy stored by the insulator in the process of force deformation. Then, the system calculates the fracture energy according to the fracture energy and the crack surface density function, which is used to judge the critical condition of crack propagation and is the key to describe the energy change in the process of crack propagation. Then, the system calculates the external load potential energy by combining the size and direction of the external load and the displacement field of the insulator, which reflects the effect of external force on the insulator. By calculating these energy terms, the system can comprehensively describe the energy state of the insulator in the process of crack propagation, and provide theoretical support for subsequent crack propagation path prediction and dynamic analysis of dielectric properties.

[0123] As an example, the material property parameters include elastic modulus, Poisson's ratio and fracture toughness parameters; the step of calculating the strain potential energy, fracture energy and external load potential energy of the insulator according to the material property parameters of the geometric model includes: calculating the strain potential energy of the insulator by the strain energy density function according to the elastic modulus and the Poisson's ratio; calculating the fracture energy of the insulator according to the fracture toughness parameters and the preset crack surface density function; calculating the external load potential energy of the insulator according to the amplitude, frequency and phase parameters of the electromagnetic force suffered by the conductor in the geometric model.

[0124] The elastic modulus is the ratio of stress to strain in the elastic deformation stage of the material, which reflects the ability of the material to resist elastic deformation, and is used to calculate the stress-strain relationship of the insulator after being subjected to force.

[0125] The Poisson's ratio is the ratio of lateral strain to longitudinal strain when the material is subjected to force, which reflects the degree of lateral deformation of the material when subjected to force, and is used to calculate the strain energy density function and then obtain the strain potential energy.

[0126] The fracture toughness parameter is a measure of the ability of the material to resist crack propagation, which is usually represented by the critical energy release rate, and is used to calculate the fracture energy, which is a key parameter for judging the critical condition of crack propagation.

[0127] The strain energy density function is a function that describes the energy stored in unit volume of material in the strain state, which is calculated by the elastic modulus and the Poisson's ratio, and reflects the energy state of the insulator after being subjected to force.

[0128] The preset crack surface density function is a function that describes the distribution density of the crack surface in the material, which is used to calculate the fracture energy together with the fracture toughness parameter, and reflects the change of energy in the process of crack propagation.

[0129] The electromagnetic force is the force generated by the action of the electromagnetic field, which acts on the conductor.

[0130] The phase parameter is phase information of the electromagnetic force over time, and is usually used together with the frequency of the electromagnetic force to describe the dynamic characteristics of the electromagnetic force.

[0131] First, the simulation prediction system substitutes the elastic modulus and Poisson's ratio of the insulator in the geometric model into the strain energy density function formula to calculate the strain potential energy distribution of the insulator after being subjected to force. Specifically, the system divides the geometric model into multiple small units by the finite element analysis method, calculates the strain energy density in each unit according to the elastic modulus and Poisson's ratio, and then integrates the strain energy densities of all units to obtain the strain potential energy of the entire insulator. This step is to quantify the energy stored by the insulator during the deformation process under force, and to provide a mechanical basis for subsequent crack propagation analysis. Second, the system calculates the fracture energy of the insulator according to the fracture toughness parameter and the preset crack surface density function. Specifically, the system combines the fracture toughness parameter with the crack surface density function to calculate the fracture energy by integration. This step is to evaluate the material's ability to resist crack propagation, which is the key basis for determining whether the crack will propagate. Finally, the system calculates the external load potential energy of the insulator according to the amplitude, frequency and phase parameters of the electromagnetic force acting on the conductor in the geometric model. The system first calculates the dynamic electromagnetic force distribution on the conductor according to the amplitude, frequency and phase parameters of the electromagnetic force, and then calculates the work done by these forces on the insulator by integration to obtain the external load potential energy.

[0132] Step S22, superimposing the strain potential energy, the fracture energy and the external load potential energy to generate a weak form control equation of the total potential energy of the motor slot opening.

[0133] It should be noted that the weak form control equation refers to a mathematical representation method of converting the control equation of a physical problem from a differential equation form to an integral form. Specifically, the weak form control equation converts the derivative term in the differential equation into an integral form by introducing a weight function (or test function), thereby reducing the smoothness requirement of the equation and making the numerical solution more stable and efficient.

[0134] Weak form control equation of the external load potential energy:

[0135]

[0136] Where u is the displacement field vector of the insulator, b is the body force density, and h is the surface boundary traction.

[0137] Weak form control equation of the fracture energy:

[0138]

[0139] Where G cThe critical energy release rate is often used as a criterion for crack propagation in brittle fracture problems. I(d) is a functional of d(x), and A(d) is the crack area density function. d(x) represents the phase field damage variable, which is a function of spatial position x, describing the damage level of the material at different locations.

[0140] The weak form governing equation of strain potential energy is:

[0141]

[0142] where w(d) is the weight function, which depends on the phase field damage variable d, describing the damage state of the material; dV represents the volume element, which is used to discretize the volume during integration; H(ψ) is a function that calculates the maximum value of the strain energy density ψ:

[0143]

[0144] where ψ(ω) is the strain energy density function, ω is the strain and related to the displacement x, t is the time maximum value calculated, and τ is the time variable.

[0145] It can be understood that first, the simulation prediction system superimposes the previously calculated strain potential energy, fracture energy, and external load potential energy to form the total potential energy expression of the motor slot opening. This step is to unify the energy from different sources into a total potential energy function. Then, the system introduces the weight function (or test function), and through the division integral and boundary condition processing, the differential form of the total potential energy is converted into the integral form to obtain the weak form governing equation. The purpose of this step is to convert the complex partial differential equation into an integral equation that is easier to solve numerically, reduce the smoothness requirement of the equation, and improve the stability and efficiency of numerical solution.

[0146] Step S23, iteratively solving the mechanical displacement field and the phase field damage variable based on the weak form governing equation to generate the evolution trend data of the crack propagation path.

[0147] It can be understood that first, the simulation prediction system sets the initial mechanical displacement field and the phase field damage variable as the starting condition for iteration based on the weak form governing equation. Then, the system gradually solves the mechanical displacement field and the phase field damage variable through numerical iteration methods such as the Newton-Raphson method. In each iteration, the system calculates the residual of the current iteration step using the weak form governing equation, and adjusts the mechanical displacement field and the phase field damage variable according to the residual until the residual meets the preset convergence criterion. This process continuously updates the position, length, and direction of the crack, thereby generating the evolution trend data of the crack propagation path.

[0148] Please refer to Figure 10 ,Figure 10 FIG. 6 shows the schematic diagrams of the insulation crack propagation state under different iteration steps for the second embodiment of the method for predicting the crack propagation and dielectric properties of the motor slot opening, wherein each subfigure corresponds to a different iteration step, from (a) iteration step = 0 to (f) iteration step = 1500, reflecting the crack propagation in the insulation layer over time. The color bar in the figure represents the value range of the damage variable d, from 0 (blue, no damage) to 1 (red, complete damage). In the initial state, there is an initial crack in the insulation layer, located at the marked position in figure (a). As the iteration step increases, the crack starts to propagate from the initial position, as shown in figures (b) to (f), the crack path gradually extends to the deep part of the insulation layer, and in figure (f) the crack has propagated to the area close to the mica tape. The sampling points A, B, C in the figure are used to monitor the changes in material properties during crack propagation. These images intuitively show the dynamic evolution process of the damage of the insulation layer during crack propagation, providing an important basis for predicting the reliability and life of the motor insulation, and helping the design, fault diagnosis and repair of the motor insulation structure.

[0149] As an example, the step of generating evolution trend data of the crack propagation path based on the iterative solution of the weak form governing equation for the mechanical displacement field and the phase field damage variable includes: discretizing the weak form governing equation into finite element equations; solving the finite element equations step by step using incremental loading to obtain the mechanical displacement field and the phase field damage variable; identifying the crack propagation region according to the numerical distribution of the phase field damage variable; determining the crack propagation direction and crack propagation rate according to the displacement gradient data of the mechanical displacement field; and generating evolution trend data of the crack propagation path according to the crack propagation region, the crack propagation direction, and the crack propagation rate.

[0150] The finite element equation refers to the algebraic equation system obtained by discretizing the weak form governing equation using the finite element method. These equation systems describe the relationship between physical quantities (such as displacement, stress, damage variable, etc.) within each finite element cell and are the basis for numerical solution. This application uses quadrilateral mesh to discretize the weak form governing equation, and the process of solving the finite element equation is that the residual vector of stress balance in a cell requires:

[0151]

[0152] Where W(u, d) is the total potential energy of the motor slot opening, and the formula from left to right is the fracture energy, the strain potential energy, the external load potential energy (representing the potential energy between the external load b and the mechanical displacement field u), and the boundary load potential energy (representing the potential energy between the boundary load h and the displacement field u).

[0153]

[0154] where, is the residual of the mechanical displacement field, indicating whether the mechanical equilibrium of the system is satisfied under the current mechanical displacement field; is the residual of the phase field damage variable, indicating whether the damage evolution of the system is satisfied under the current phase field damage variable.

[0155]

[0156] where, [K G ] is the global stiffness matrix, containing the mechanical properties and geometric information of the insulating materials (epoxy resin and mica tape); {δ} is the unknown variable vector, containing the mechanical displacement field u and the phase field damage variable d of each node; u 1 and u 2 are the displacements of the node in the x and y directions, respectively; {R G} is the force residual term, containing all external loads acting directly on the nodes, such as electromagnetic forces from the conductor.

[0157] Incremental loading refers to the method of gradually applying external loads (such as electromagnetic forces) to the model in small increments, rather than applying all loads at once. This method can better capture the nonlinear behavior during crack propagation, ensuring the stability and accuracy of numerical solutions.

[0158] Numerical distribution refers to the specific numerical distribution of the phase field damage variable in the geometric model. These numbers reflect the damage degree at different positions and are usually represented in the form of color or contour lines in the cloud chart.

[0159] Crack propagation area refers to the area with high damage degree (close to 1) in the numerical distribution of the phase field damage variable. These areas usually correspond to the actual position and propagation path of the crack.

[0160] Displacement gradient data refers to the gradient information of displacement change in the mechanical displacement field, usually obtained by calculating the derivative of the displacement field. Displacement gradient data can reflect the stress concentration near the crack tip and is used to determine the crack propagation direction and rate.

[0161] Crack propagation direction refers to the direction followed by the crack during propagation. By analyzing the displacement gradient data and the distribution of damage variables, the crack propagation direction at each time step can be determined.

[0162] Crack propagation rate refers to the distance of crack propagation per unit time. By analyzing the displacement gradient data and the change of damage variables, the crack propagation rate at each time step can be calculated.

[0163] Firstly, the simulation prediction system discretizes the weak form control equation by the finite element method. Specifically, the geometric model of the motor slot exit is divided into multiple small units, and the displacement field and phase field damage variable in each unit are approximated by a polynomial function. Then, the continuous weak form equation is converted into a discrete algebraic equation system by using numerical integration method. This step is to convert the complex continuous problem into a discrete problem that can be processed by the computer, providing a basis for subsequent numerical solution. Secondly, the system uses incremental loading method to apply the external load (such as electromagnetic force) to the model in multiple small increments. Each increment is solved once to update the mechanical displacement field and phase field damage variable. This step is to simulate the dynamic expansion behavior of the crack during the gradual loading process and avoid numerical instability caused by one-time loading. Then, the system checks the size of the damage variable in each unit based on the numerical distribution of the phase field damage variable. When the damage variable approaches 1, it is considered that the area is a crack propagation area. This step is to accurately identify the position and range of the crack. Next, the system calculates the displacement gradient of each unit based on the displacement gradient data of the mechanical displacement field. By analyzing the size and direction of the displacement gradient, the crack propagation direction and propagation rate are determined. This step is to predict how the crack propagates in the material. Finally, the system generates the evolution trend data of the crack propagation path by integrating the information of the crack propagation area, propagation direction and propagation rate. The position, length and direction of the crack at different loading steps are recorded. This step provides complete dynamic information of the crack propagation, which provides a basis for subsequent analysis and evaluation.

[0164] Firstly, the embodiment calculates the strain potential energy, fracture energy and external load potential energy of the insulator according to the material attribute parameters of the geometric model. This step can comprehensively quantify the energy state of the insulator during the stress and crack propagation process. Then, these energy items are superimposed to generate the weak form control equation of the total potential energy of the motor slot exit. This step converts the complex partial differential equation into an integral equation that is easier to solve numerically, reducing the smoothness requirement of the equation. Finally, the mechanical displacement field and phase field damage variable are iteratively solved based on the weak form control equation to generate the evolution trend data of the crack propagation path. This step can dynamically simulate the crack propagation process, providing an important basis for reliability evaluation and fault diagnosis of the motor insulation structure, helping to early warning potential insulation failure and ensuring the safe operation of the motor.

[0165] The application also provides a motor slot exit crack propagation and dielectric performance prediction device, which is described in detail in Figure 11 , and the motor slot exit crack propagation and dielectric performance prediction device comprises:

[0166] A model construction module 10 is configured to construct a geometric model of a motor slot exit, wherein the geometric model comprises a stator core, a conductor and an insulator, and an initial electric potential field is set based on voltage levels of the stator core and the conductor.

[0167] a mechanics solving module 20, configured to solve a mechanical displacement field and a phase field damage variable according to material property parameters of the geometric model, and generate evolution trend data of a crack propagation path;

[0168] an electric field analyzing module 30, configured to calculate an electric damage variable and an electric field distortion data of the geometric model during crack propagation according to a Poisson equation, the initial electric potential field, the evolution trend data, and a dielectric constant of the insulator;

[0169] a report generating module 40, configured to obtain a comprehensive prediction report including a crack propagation path prediction map and a dielectric performance degradation cloud map according to the evolution trend data, the electric damage variable, and the electric field distortion data.

[0170] In an embodiment, the mechanics solving module 20 is further configured to calculate a strain potential energy, a fracture energy, and an external load potential energy of the insulator according to material property parameters of the geometric model; superimpose the strain potential energy, the fracture energy, and the external load potential energy to generate a weak form governing equation of the total potential energy of the slot of the electric machine; and iteratively solve a mechanical displacement field and a phase field damage variable based on the weak form governing equation, and generate evolution trend data of a crack propagation path.

[0171] In an embodiment, the mechanics solving module 20 is further configured to calculate a strain potential energy of the insulator by a strain energy density function according to the elastic modulus and the Poisson's ratio; calculate a fracture energy of the insulator according to the fracture toughness parameter and a preset crack surface density function; and calculate an external load potential energy of the insulator according to an amplitude, a frequency, and a phase parameter of an electromagnetic force suffered by the conductor in the geometric model.

[0172] In an embodiment, the mechanics solving module 20 is further configured to discretize the weak form governing equation into a finite element equation; solve the finite element equation step by step in an incremental loading manner to obtain a mechanical displacement field and a phase field damage variable; identify a crack propagation region according to a numerical distribution of the phase field damage variable; determine a crack propagation direction and a crack propagation rate according to displacement gradient data of the mechanical displacement field; and generate evolution trend data of a crack propagation path according to the crack propagation region, the crack propagation direction, and the crack propagation rate.

[0173] In an embodiment, the electric field analysis module 30 is further configured to obtain an initial permittivity distribution of the insulator from the geometric model; determine a crack region of the insulator according to the evolution trend data, and update a permittivity of the crack region to an air permittivity to obtain a target permittivity distribution; solve a Poisson equation according to the target permittivity distribution and a potential boundary condition of the initial electric potential field to obtain a dynamic potential distribution after crack propagation; calculate a potential difference between the dynamic potential distribution and the initial electric potential field at each spatial point to obtain a potential distortion data set; perform normalization processing on the potential distortion data set according to a preset electric damage threshold to obtain an electric damage variable of the geometric model; and perform gradient operation on the dynamic potential distribution to extract an electric field strength extreme value of a crack tip region to generate an electric field distortion data of the geometric model.

[0174] In an embodiment, the model construction module 10 is further configured to construct a three-dimensional geometric model of a stator core; set a conductor in a core slot part of the three-dimensional geometric model, and set an insulator between the conductor and the stator core; set a position, a length, and a direction parameter of an initial crack on the insulator; and set material attribute parameters of the stator core and the conductor after the insulator is set to complete model construction.

[0175] In an embodiment, the report generation module 40 is further configured to convert the evolution trend data into a visual chart, and mark a crack length, a bifurcation angle, and an expansion direction on the visual chart to obtain a crack propagation path prediction map; identify a region in which a dielectric constant attenuation exceeds a preset threshold by a color gradient mapping algorithm according to spatial distribution data of the electric damage variable to generate a dielectric performance degradation cloud chart; mark a high-risk breakdown region on the dielectric performance degradation cloud chart according to an electric field strength extreme value region in the electric field distortion data; and perform spatial superposition on the crack propagation path prediction map and the dielectric performance degradation cloud chart after the high-risk breakdown region is marked to obtain a comprehensive prediction report.

[0176] The motor slot outlet crack propagation and dielectric performance prediction device provided in the application adopts the motor slot outlet crack propagation and dielectric performance prediction method in the above embodiments, and can solve the technical problem of how to accurately predict a motor slot outlet insulator crack propagation path and dielectric performance dynamic change. Compared with the prior art, the motor slot outlet crack propagation and dielectric performance prediction device provided in the application has the same beneficial effects as the motor slot outlet crack propagation and dielectric performance prediction method provided in the above embodiments, and other technical features in the motor slot outlet crack propagation and dielectric performance prediction device are the same as the features disclosed in the above embodiments, which will not be described herein.

[0177] This application provides a device for predicting the propagation of cracks at the slot of an electric motor and its dielectric properties. The device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method for predicting the propagation of cracks at the slot of an electric motor in the first embodiment described above.

[0178] The following is for reference. Figure 12 This document illustrates a structural schematic diagram of a device suitable for predicting the propagation of cracks and dielectric properties at the slot of a motor, as described in the embodiments of this application. The device for predicting the propagation of cracks and dielectric properties at the slot of a motor, as described in the embodiments of this application, may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 12 The illustrated device for predicting the crack propagation and dielectric properties at the motor slot is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0179] like Figure 12As shown, the motor slot outlet crack propagation and dielectric property prediction device can include a processing device 1001 (e.g., a central processing unit, a graphics processing unit, etc.) that can perform various appropriate actions and processes according to a program stored in a ROM (Read Only Memory) 1002 or a program loaded from a storage device 1003 into a RAM (Random Access Memory) 1004. In the RAM 1004, various programs and data required for operation of the motor slot outlet crack propagation and dielectric property prediction device are also stored. The processing device 1001, the ROM 1002, and the RAM 1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, an LCD (Liquid Crystal Display), a speaker, a vibrator, etc.; the storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the motor slot outlet crack propagation and dielectric property prediction device to communicate wirelessly or wiredly with other devices to exchange data. Although the motor slot outlet crack propagation and dielectric property prediction device having various systems is shown in the figure, it should be understood that all of the shown systems are not required to be implemented or possessed. More or less systems can be alternatively implemented or possessed.

[0180] In particular, the processes described above with reference to the flowcharts can be implemented as a computer software program according to embodiments of the present disclosure. For example, embodiments of the present disclosure include a computer program product comprising a computer program carrying out the methods shown in the flowcharts on a computer readable medium. In such embodiments, the computer program can be downloaded and installed from a network through the communication device, or installed from the storage device 1003, or installed from the ROM 1002. When the computer program is executed by the processing device 1001, the above-described functions defined in the methods of embodiments of the present disclosure are performed.

[0181] The motor slot outlet crack propagation and dielectric performance prediction device provided by the application adopts the motor slot outlet crack propagation and dielectric performance prediction method in the above embodiment, and can solve the technical problem of how to accurately predict the motor slot outlet insulation crack propagation path and dielectric performance dynamic change. Compared with the prior art, the motor slot outlet crack propagation and dielectric performance prediction device provided by the application has the same beneficial effects as the motor slot outlet crack propagation and dielectric performance prediction method provided by the above embodiment, and other technical features in the motor slot outlet crack propagation and dielectric performance prediction device are the same as the features disclosed in the previous embodiment method, which will not be repeated here.

[0182] It should be understood that parts of the present application can be realized by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0183] The present application provides a computer readable storage medium having stored thereon computer readable program instructions (i.e., computer programs) for executing the motor slot outlet crack propagation and dielectric performance prediction method in the above embodiment.

[0184] The computer readable storage medium provided by the present application may, for example, be a U disk, but is not limited to an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system or device, or any combination of the above. More specific examples of computer readable storage media can include, but are not limited to, an electrical connection having one or more conductive wires, a portable computer disk, a hard disk, a RAM (Random Access Memory), a ROM (Read Only Memory), an EPROM (Erasable Programmable Read Only Memory or flash memory), an optical fiber, a CD-ROM (CD-Read Only Memory), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present embodiment, the computer readable storage medium can be any tangible medium containing or storing a program that can be used or combined with an instruction execution system, system or device. The program code contained on the computer readable storage medium can be transmitted by any appropriate medium, including but not limited to: wire, optical cable, RF (Radio Frequency), etc., or any suitable combination of the above.

[0185] The computer readable storage medium can be included in the motor slot opening crack propagation and dielectric performance prediction device, or can exist separately and not be assembled into the motor slot opening crack propagation and dielectric performance prediction device.

[0186] The computer readable storage medium carries one or more programs, and when the one or more programs are executed by the motor slot opening crack propagation and dielectric performance prediction device, the motor slot opening crack propagation and dielectric performance prediction device is caused to: construct a geometric model of a motor slot opening, the geometric model including a stator core, a conductor and an insulator, and set an initial electric potential field based on a voltage level of the stator core and the conductor; solve a mechanical displacement field and a phase field damage variable according to a material attribute parameter of the geometric model, and generate evolution trend data of a crack propagation path; calculate an electric damage variable and an electric field distortion data of the geometric model in a crack propagation process according to a Poisson equation, the initial electric potential field, the evolution trend data and a dielectric constant of the insulator; and obtain a comprehensive prediction report including a crack propagation path prediction graph and a dielectric performance degradation cloud chart according to the evolution trend data, the electric damage variable and the electric field distortion data.

[0187] Computer program code for carrying out operations of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0188] The flow and block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flow and block diagrams can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustrations, and combinations thereof, can be implemented by a dedicated hardware-based system that performs the specified functions or operations, or combinations of hardware and software.

[0189] The modules involved in the embodiments of the present application can be implemented in the form of software or in the form of hardware. In some cases, the names of the modules do not constitute a limitation on the modules themselves.

[0190] The readable storage medium provided by the present application is a computer readable storage medium, which stores computer readable program instructions (i.e., a computer program) for executing the above-mentioned motor slot outlet crack propagation and dielectric performance prediction method, and can solve the technical problem of how to accurately predict the motor slot outlet insulation crack propagation path and dielectric performance dynamic change. Compared with the prior art, the computer readable storage medium provided by the present application has the same beneficial effects as the motor slot outlet crack propagation and dielectric performance prediction method provided by the above-mentioned embodiments, and will not be described here.

[0191] The present application also provides a computer program product comprising a computer program, which, when executed by a processor, implements the steps of the motor slot outlet crack propagation and dielectric performance prediction method as described above.

[0192] The computer program product provided by the present application can solve the technical problem of how to accurately predict the motor slot outlet insulation crack propagation path and dielectric performance dynamic change. Compared with the prior art, the computer program product provided by the present application has the same beneficial effects as the motor slot outlet crack propagation and dielectric performance prediction method provided by the above-mentioned embodiments, and will not be described here.

[0193] The above only describes some embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for predicting the propagation of cracks and dielectric properties at the slot opening of an electric motor, characterized in that, The method includes: A geometric model of the motor slot is constructed, the geometric model including stator core, conductor and insulator, and an initial potential field is set based on the voltage level of the stator core and the conductor; Based on the material property parameters of the geometric model, the mechanical displacement field and phase field damage variables are solved to generate the evolution trend data of the crack propagation path; Based on the Poisson equation, the initial potential field, the evolution trend data, and the dielectric constant of the insulator, the electrical damage variables and electric field distortion data of the geometric model during crack propagation are calculated. Based on the evolution trend data, the electrical damage variables, and the electric field distortion data, a comprehensive prediction report is obtained, which includes a crack propagation path prediction map and a dielectric property degradation cloud map. The step of solving the mechanical displacement field and phase field damage variables based on the material property parameters of the geometric model to generate the evolution trend data of crack propagation path includes: Calculate the strain potential energy, fracture energy, and external load potential energy of the insulator based on the material property parameters of the geometric model. The weak form control equation for the total potential energy at the motor slot outlet is generated by superimposing the strain potential energy, the fracture energy, and the external load potential energy. Based on the weak form control equation, the mechanical displacement field and phase field damage variables are iteratively solved to generate the evolution trend data of crack propagation path; The step of calculating the electrical damage variables and electric field distortion data of the geometric model during crack propagation based on the Poisson equation, the initial electric potential field, the evolution trend data, and the dielectric constant of the insulator includes: Obtain the initial dielectric constant distribution of the insulator from the geometric model; Based on the evolution trend data, the crack region of the insulator is determined, and the dielectric constant of the crack region is updated to the air dielectric constant to obtain the target dielectric constant distribution; The Poisson equation is solved based on the target dielectric constant distribution and the potential boundary conditions of the initial potential field to obtain the dynamic potential distribution after crack propagation. Calculate the potential difference between the dynamic potential distribution and the initial potential field at each spatial point to obtain the potential distortion dataset; The potential distortion dataset is normalized according to a preset electrical damage threshold to obtain the electrical damage variables of the geometric model. Gradient calculations are performed on the dynamic potential distribution to extract the extreme values ​​of the electric field intensity in the crack tip region, thereby generating the electric field distortion data of the geometric model.

2. The method as described in claim 1, characterized in that, The material property parameters include elastic modulus, Poisson's ratio, and fracture toughness parameters. The steps of calculating the strain potential energy, fracture energy, and external load potential energy of the insulator based on the material property parameters of the geometric model include: Based on the elastic modulus and the Poisson's ratio, the strain potential energy of the insulator is calculated using the strain energy density function. The fracture energy of the insulator is calculated based on the fracture toughness parameters and the preset crack surface density function. Based on the amplitude, frequency, and phase parameters of the electromagnetic force acting on the conductor in the geometric model, the potential energy of the external load acting on the insulator is calculated.

3. The method as described in claim 1, characterized in that, The step of iteratively solving the mechanical displacement field and phase field damage variables based on the weak form governing equation to generate crack propagation path evolution trend data includes: Discretize the weak form governing equations into finite element equations; By using an incremental loading method, the finite element equations are solved step by step to obtain the mechanical displacement field and phase field damage variables. Based on the numerical distribution of the phase field damage variables, identify the crack propagation region; Based on the displacement gradient data of the mechanical displacement field, the crack propagation direction and crack propagation rate are determined; Based on the crack propagation region, the crack propagation direction, and the crack propagation rate, evolution trend data of the crack propagation path is generated.

4. The method as described in claim 1, characterized in that, The step of constructing the geometric model of the motor slot opening, wherein the geometric model includes the stator core, conductor, and insulator, includes: Establish a three-dimensional geometric model of the stator core; A conductor is provided in the core slot of the three-dimensional geometric model, and an insulator is provided between the conductor and the stator core; The location, length, and orientation parameters of the initial crack are set on the insulator; Once the insulator is set, the material property parameters of the stator core and conductor are set to complete the model construction.

5. The method as described in claim 1, characterized in that, The step of obtaining a comprehensive prediction report including a crack propagation path prediction map and a dielectric property degradation cloud map based on the evolution trend data, the electrical damage variables, and the electric field distortion data includes: The evolution trend data is converted into a visualization chart, and the crack length, bifurcation angle and propagation direction are marked on the visualization chart to obtain a crack propagation path prediction chart. Based on the spatial distribution data of the electrical damage variables, the region where the dielectric constant decay exceeds a preset threshold is identified by a color gradient mapping algorithm, and a dielectric performance degradation cloud map is generated. Based on the extreme regions of electric field intensity in the electric field distortion data, high-risk breakdown regions are marked on the dielectric property degradation cloud map. Once the high-risk breakdown area is marked, the crack propagation path prediction map and the dielectric property degradation cloud map are spatially superimposed to obtain a comprehensive prediction report.

6. A device for predicting crack propagation and dielectric properties at the slot of an electric motor, characterized in that, The device includes: The model building module is used to build a geometric model of the motor slot, which includes a stator core, conductors and insulators, and sets an initial potential field based on the voltage level of the stator core and the conductors; The mechanical solution module is used to solve the mechanical displacement field and phase field damage variables based on the material property parameters of the geometric model, and generate the evolution trend data of crack propagation path; The mechanics solution module is also used to calculate the strain potential energy, fracture energy and external load potential energy of the insulator based on the material property parameters of the geometric model; The weak form control equation for the total potential energy at the motor slot outlet is generated by superimposing the strain potential energy, the fracture energy, and the external load potential energy. Based on the weak form control equation, the mechanical displacement field and phase field damage variables are iteratively solved to generate the evolution trend data of crack propagation path; The electric field analysis module is used to calculate the electrical damage variables and electric field distortion data of the geometric model during crack propagation based on the Poisson equation, the initial electric potential field, the evolution trend data, and the dielectric constant of the insulator. The electric field analysis module is also used to obtain the initial dielectric constant distribution of the insulator from the geometric model; Based on the evolution trend data, the crack region of the insulator is determined, and the dielectric constant of the crack region is updated to the air dielectric constant to obtain the target dielectric constant distribution; The Poisson equation is solved based on the target dielectric constant distribution and the potential boundary conditions of the initial potential field to obtain the dynamic potential distribution after crack propagation. Calculate the potential difference between the dynamic potential distribution and the initial potential field at each spatial point to obtain the potential distortion dataset; The potential distortion dataset is normalized according to a preset electrical damage threshold to obtain the electrical damage variables of the geometric model. Gradient calculation is performed on the dynamic potential distribution to extract the extreme values ​​of the electric field intensity in the crack tip region, thereby generating the electric field distortion data of the geometric model; The report generation module is used to generate a comprehensive prediction report, including a crack propagation path prediction map and a dielectric property degradation cloud map, based on the evolution trend data, the electrical damage variables, and the electric field distortion data.

7. A device for predicting the propagation of cracks and dielectric properties at the slot of an electric motor, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the method for predicting the propagation of motor slot cracks and dielectric properties as claimed in any one of claims 1 to 5.

8. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the method for predicting the propagation of cracks at the slot of a motor as described in any one of claims 1 to 5.

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