Method and system for identifying insulation weak points in motor slot

Abstract

The invention relates to the technical field of motors, in particular to a method and a system for identifying insulation weak spots in a motor slot, which can accurately identify an electric stress concentration area in the motor slot based on an electromagnetic field modeling technology, and can efficiently judge the position and degree of the insulation weak spots in the slot in combination with performance data of an insulation system. According to the method, the potential insulation problem can be found in advance, so that the operation safety and reliability of the motor are improved, and the risk of motor fault occurrence is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and specifically to a method and system for identifying weak points of insulation in motor slots. Background Art

[0002] The insulation materials of concentrated winding motors may degrade to varying degrees during long-term operation, especially in the stator slots. Due to the action of current and electric field during operation, the electrical stress distribution is uneven, and local weaknesses are likely to occur in the insulation structure in the slots at the location of the maximum stress, thus affecting the long-term stability and reliability of the motor. Traditional insulation performance detection methods mostly rely on manual inspection or traditional local detection techniques, and it is difficult to comprehensively and accurately identify weak points of insulation. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a method and system for identifying weak points of insulation in motor slots to solve the problems in the background art.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A method for identifying weak points of insulation in motor slots of the present invention includes the steps of:

[0006] Constructing a motor model based on the geometric structure of a concentrated winding motor;

[0007] Performing simulation analysis on the motor model to obtain static parameters and dynamic parameters of the concentrated winding motor, where the static parameters include the distributed capacitance of the winding in the electrostatic field, and the dynamic parameters include the AC resistance and AC inductance of the winding in the eddy current field;

[0008] Constructing a simplified circuit model of the concentrated winding motor, and determining the voltage distribution characteristics of the concentrated winding motor based on the static parameters, the dynamic parameters, and the simplified circuit model;

[0009] Performing discharge risk analysis based on the voltage distribution characteristics extraction and the geometric structure of the concentrated winding motor to obtain potential weak points with discharge risks in the motor stator slots;

[0010] Screening the potential weak points based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points to obtain weak points of insulation in the motor slots.

[0011] In an embodiment of the present application, it further includes:

[0012] Verifying the weak points of insulation based on electrical tests to obtain reliable weak points of insulation.

[0013] In an embodiment of the present application, the motor model is simulated and analyzed to obtain the static parameters of the concentrated winding motor, including:

[0014] The capacitance of the stator slots of the motor model is calculated in an electrostatic field simulation environment to obtain a capacitance simulation result;

[0015] The measured result of the capacitance of the stator slots is obtained, and the capacitance simulation result is verified based on the measured result, and the verified capacitance simulation result is used as the static parameter of the concentrated winding motor.

[0016] In an embodiment of the present application, the motor model is simulated and analyzed to obtain the dynamic parameters of the concentrated winding motor, including:

[0017] The oscillation frequency of the power supply output pulse in the eddy current field simulation environment is measured, and the AC resistance and AC inductance of the winding end at the oscillation frequency are calculated in the eddy current field simulation environment to obtain the dynamic parameters of the concentrated winding motor.

[0018] In an embodiment of the present application, a simplified circuit model of the concentrated winding motor is constructed, including:

[0019] Based on two series-connected adjacent coils of the same phase, a first simplified circuit model is constructed, wherein the first simplified circuit model is used to verify the uneven voltage distribution existing in the same coil;

[0020] Taking half of each coil as a unit, a second simplified circuit model of the entire winding of the stator of the concentrated winding motor in the magnetic field is constructed, wherein the second simplified circuit model is used to verify the voltage distribution trend in the entire stator winding;

[0021] Based on a group of 1 / 4 windings connected in a Y shape, a third simplified circuit model is constructed with a half-turn conductor as a unit, wherein the third simplified circuit model is used to verify the electrical stress distribution of each turn of the conductor in the magnetic field.

[0022] In an embodiment of the present application, based on the static parameters, the dynamic parameters, and the simplified circuit model, the voltage distribution characteristics of the concentrated winding motor are determined, including:

[0023] High-frequency equivalent circuits of the first simplified circuit model, the second simplified circuit model, and the third simplified circuit model are respectively constructed;

[0024] Relationship equations of the currents and voltages of multiple nodes in the high-frequency equivalent circuit are established;

[0025] Construct a differential equation of the circuit based on the relationship equations of the currents and voltages at multiple nodes in the high-frequency equivalent circuit, and solve the differential equation to obtain the voltage distribution characteristics of the concentrated winding motor, where the voltage distribution characteristics include the voltage values at multiple positions.

[0026] In an embodiment of the present application, perform a discharge risk analysis based on the extraction of the voltage distribution characteristics and the geometric structure of the concentrated winding motor to obtain potential weak points with discharge risks in the stator slots of the motor, including:

[0027] Extract a target region that meets the target conditions based on the voltage distribution characteristics, where the target conditions are one or a combination of the following: the overall electric field intensity in the region is greater than a preset intensity threshold; the change rate of the electric field intensity in the region is greater than a preset speed threshold; the local electric stress in the region is greater than a preset stress threshold;

[0028] Determine the voltage values at multiple positions in the target region based on the voltage distribution characteristics, and use the voltage values at multiple positions in the target region as simulation inputs to calculate the electric field intensity gradient in the target region;

[0029] Compare the electric field intensity gradient in the target region with the theoretical calculated value of the onset of discharge in air, and determine whether there is a discharge risk in the target region based on the comparison result; if so, use the region with the discharge risk as a weak point.

[0030] In an embodiment of the present application, based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points, screen the potential weak points to obtain the insulation weak points in the motor slots, including:

[0031] Compare the voltage distribution characteristics of the potential weak points with the partial discharge inception voltage of the potential weak points, where the partial discharge inception voltage is determined by the insulation performance data, and the insulation performance data includes the heat resistance level and the dielectric constant;

[0032] Use the potential weak points with voltages greater than the partial discharge inception voltage as the insulation weak points in the electrode slots.

[0033] In an embodiment of the present application, it further includes:

[0034] Modify and adjust the insulation weak points, and after the modification and adjustment, return to constructing the motor model based on the geometric structure of the concentrated winding motor until there are no insulation weak points in the motor.

[0035] The present application also provides a recognition system for insulation weak points in a motor slot. The system is used to implement the above-mentioned recognition method for insulation weak points in a motor slot. The system includes:

[0036] A model construction module for constructing a motor model based on the geometric structure of a concentrated winding motor;

[0037] A simulation analysis module for performing simulation analysis on the motor model to obtain the static parameters and dynamic parameters of the concentrated winding motor, where the static parameters include the distributed capacitance of the winding in the electrostatic field, and the dynamic parameters include the AC resistance and AC inductance of the winding in the eddy current field;

[0038] A voltage distribution analysis module for constructing a simplified circuit model of the concentrated winding motor and determining the voltage distribution characteristics of the concentrated winding motor based on the static parameters, the dynamic parameters, and the simplified circuit model;

[0039] A potential weak point preliminary selection module for performing discharge risk analysis based on the voltage distribution characteristics extraction and the geometric structure of the concentrated winding motor to obtain potential weak points with discharge risks in the stator slots of the motor;

[0040] A weak point determination module for screening the potential weak points based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points to obtain the insulation weak points in the motor slots.

[0041] The beneficial effects of the present invention are as follows: A method and system for identifying insulation weak points in motor slots of the present invention construct a motor model based on the geometric structure of a concentrated winding motor; perform simulation analysis on the motor model to obtain the static parameters and dynamic parameters of the concentrated winding motor; construct a simplified circuit model of the concentrated winding motor and determine the voltage distribution characteristics of the concentrated winding motor based on the static parameters, dynamic parameters, and the simplified circuit model; perform discharge risk analysis based on the voltage distribution characteristics extraction and the geometric structure of the concentrated winding motor to obtain potential weak points with discharge risks in the stator slots of the motor; screen the potential weak points by combining the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points to obtain the insulation weak points in the motor slots. The present application is based on electromagnetic field modeling technology, can accurately identify the regions of electric stress concentration in the motor slots, and combined with the performance data of the insulation system, can efficiently judge the position and degree of the insulation weak points in the slots. This method can discover potential insulation problems in advance, thereby improving the operation safety and reliability of the motor and reducing the risk of motor failures. Description of the Drawings

[0042] The present invention will be further described below with reference to the drawings and embodiments:

[0043] Figure 1 is a flowchart of a method for identifying insulation weak points in motor slots shown in an embodiment of the present application;

[0044] Figure 2Flow chart for extracting static and dynamic parameters in an embodiment of this application

[0045] Figure 3 Schematic diagram of a high - frequency equivalent circuit in an embodiment of this application

[0046] Figure 4 Flow chart of a weak - point identification method in an embodiment of this application

[0047] Figure 5 Schematic diagram of the positions of main insulation, phase - to - phase insulation, and turn - to - turn insulation in an embodiment of this application

[0048] Figure 6 Schematic diagram of a modification or adjustment process in an embodiment of this application Figure 7 Structural diagram of a system for identifying weak insulation points in a motor slot shown in an embodiment of this application Detailed implementation manners

[0049] The following uses specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0050] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the layers related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the layers in actual implementation. The type, quantity, and ratio of each layer in actual implementation can be arbitrarily changed, and the layer layout type may also be more complex.

[0051] In the following description, a large number of details are explored to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details.

[0052] Figure 1 Is a flow chart of a method for identifying weak insulation points in a motor slot shown in an embodiment of this application, as Figure 1 shown: A method for identifying weak insulation points in a motor slot in this embodiment uses electromagnetic field simulation analysis technology to identify multiple potential electric stress concentration regions in the motor slot, and through comparative analysis with the performance parameters of the insulation system in this region, determines whether there are weak points in the slot insulation.

[0053] This application may include steps S110 to S150:

[0054] S110, constructing a motor model based on the geometric structure of the concentrated winding motor;

[0055] This application conducts modeling in a simulation tool. For example, a model is drawn in Maxwell based on the geometric structure of the concentrated winding.

[0056] S120, performing simulation analysis on the motor model to obtain the static parameters and dynamic parameters of the concentrated winding motor. Among them, the static parameters include the distributed capacitance of the winding in the electrostatic field, and the dynamic parameters include the AC resistance and AC inductance of the winding in the eddy current field;

[0057] Figure 2 is the extraction flowchart of the static parameters and dynamic parameters in an embodiment of this application. As Figure 2 shown, in this embodiment, numerical methods (such as the finite element analysis method) are used to calculate the static parameters of each structure in the electric and magnetic fields, including winding capacitance, resistance, and end inductance. Considering the current distribution, magnetic field distribution, and electric field change under the operating conditions of the motor, a field-circuit coupling model is used to calculate the dynamic parameters, including the inductance of the wire in the stator slot in the magnetic field.

[0058] Specifically, the distributed capacitance is calculated in the electrostatic field module of Maxwell. The complete construction of the insulation structure in the slot is completed through scaling and subtraction operations, and a model of a stator slot and the conductor therein is drawn for calculation. The size of the capacitance is mainly related to the medium between the two conductors, as well as the distance and facing area between the two conductors. In addition, the simulation results are verified through actual measurement.

[0059] Then, the calculation of the end AC resistance and inductance is realized in the eddy current field in Maxwell. First, the oscillation frequency of the power supply output pulse is actually measured, and then a 3D model of the corresponding structure is drawn, and the AC resistance and inductance are calculated at this frequency.

[0060] S130, constructing a simplified circuit model of the concentrated winding motor, and determining the voltage distribution characteristics of the concentrated winding motor based on the static parameters, the dynamic parameters, and the simplified circuit model;

[0061] In this application, combined with the regularity and symmetry of the concentrated winding wiring method, three simplified circuit models are established respectively to extract the voltage distribution characteristics. They are respectively:

[0062] (1) Based on two series adjacent coils of the same phase, constructing a first simplified circuit model;

[0063] Specifically, in a magnetic field environment, an accurate 2D model of two series-connected adjacent coils in the same phase is drawn to verify that there will be no serious uneven voltage distribution inside a coil.

[0064] (2) Taking half of each coil as a unit, construct a second simplified circuit model of the full winding of the concentrated winding motor stator in a magnetic field;

[0065] Specifically, taking half of each coil as a unit, establish a 2D model of the full winding of the prototype stator in a magnetic field to obtain the voltage distribution trend in the entire stator winding.

[0066] (3) Based on a set of 1 / 4 windings connected in Y, construct a third simplified circuit model with a half-turn conductor as a unit.

[0067] Specifically, select a set of 1 / 4 windings connected in Y and perform accurate modeling with a half-turn conductor as a unit to observe the electrical stress distribution of each turn of the conductor in a magnetic field.

[0068] Combining the three models can comprehensively evaluate the voltage distribution level in the concentrated winding.

[0069] In this embodiment, based on the static parameters, the dynamic parameters, and the simplified circuit model, determine the voltage distribution characteristics of the concentrated winding motor, including:

[0070] S131, respectively construct high-frequency equivalent circuits of the first simplified circuit model, the second simplified circuit model, and the third simplified circuit model;

[0071] Draw corresponding high-frequency equivalent circuits for the three simplified circuit models respectively, Figure 3 which is a schematic diagram of the high-frequency equivalent circuit in an embodiment of the present application. As Figure 3 shown, T1 and T2 are both equivalent elements. The equivalent elements in each circuit simulation unit correspond to the wires at the corresponding positions in the magnetic field model, representing the dynamic parameters of the conductors in the slots calculated by the field-circuit coupling method in the magnetic field; R e1 and R e2 represent the AC resistance calculated in the eddy current field, L e1 and L e2 represent the AC inductance calculated in the eddy current field; C 10 represents the capacitance to the ground of the first unit conductor, C 20 represents the capacitance to the ground of the second unit conductor, C 1,m represents the capacitance between the first conductor and the mth conductor adjacent to it, C 2,m represents the capacitance between the second conductor and the mth conductor adjacent to it, and the capacitance parameter values are calculated in the electrostatic field.

[0072] S132. Establish the relationship equations for the currents and voltages of multiple nodes in the high-frequency equivalent circuit;

[0073] According to Kirchhoff's current and voltage laws, the current ii i and voltage u i of node i in the high-frequency circuit satisfy the following relationship equation:

[0074]

[0075] where ii i is the current in the i-th conductor of the series circuit, ii i+1 is the current in the (i + 1)-th conductor, C i,0 is the parasitic capacitance of the corresponding conductor to the ground. C i,k is the parasitic capacitance between the i-th conductor and the k-th conductor in the circuit, u i and u k are the voltages to the ground of C i,0 and C i,k respectively. u i-1 is the voltage to the ground of the (i - 1)-th node. When i is equal to 1, u i-1 = u0, R i is the resistance of the i-th conductor. L i,i is the self-inductance of the i-th conductor, and M i,k is the mutual inductance between the i-th conductor and the k-th conductor.

[0076] S133. Based on the relationship equations for the currents and voltages of multiple nodes in the high-frequency equivalent circuit, construct a differential equation for the circuit and solve the differential equation to obtain the voltage distribution characteristics of the concentrated winding motor, where the voltage distribution characteristics include voltage values at multiple positions.

[0077] According to the above relationship equations, a differential equation for the circuit can be established:

[0078] RI + Z(dI / dt) = U

[0079] Y(dU / dt) = I

[0080] where R is the matrix of AC resistance; Z is the inductance matrix; I is the matrix of current; U is the matrix of voltage;

[0081] In this embodiment, there is inductance (T i + L e,i ) on the main diagonal, mutual inductance M i,k at (i, k), and i and k are determined according to the winding structure; Y is the matrix of parasitic capacitance. The matrix I of current and the matrix U of voltage are as follows:

[0082] I = [i1,..., i i ,…, i2n

[0083] U = [u1, …, u i , …, u 2n

[0084] where n is the number of turns of the winding, and 2n represents the number of simulation units.

[0085] Finally, to be consistent with the measured values, connect the winding structure and apply a power supply excitation, then the voltage distribution can be calculated, and the parts with a relatively large voltage between windings can be located.

[0086] S140. Based on the extraction of the voltage distribution characteristics and the geometric structure of the concentrated winding motor, perform a discharge risk analysis to obtain potential weak points with discharge risks in the stator slots of the motor;

[0087] Figure 4 is a flowchart of a weak point identification method in an embodiment of the present application. As Figure 4 shown, in this embodiment, according to the voltage distribution characteristics described above, identify the regions with strong electrical stress in the stator slots of the motor, and analyze the insulation structure types of these regions. And extract the weak points among them, specifically including:

[0088] S141. Based on the voltage distribution characteristics, extract a target region that meets the target conditions, where the target conditions are one or a combination of the following: the overall electric field strength in the region is greater than a preset strength threshold; the change rate of the electric field strength in the region is greater than a preset speed threshold; the local electrical stress in the region is greater than a preset stress threshold;

[0089] In the present application, key attention is paid to the regions with a relatively large electric field strength, rapid change, or local high electrical stress, especially near the wedge-shaped air gap.

[0090] S142. Based on the voltage distribution characteristics, determine the voltage values at multiple positions in the target region, and use the voltage values at multiple positions in the target region as simulation inputs to calculate the electric field strength gradient in the target region;

[0091] Specifically, draw a three-dimensional model of the target region, and use the voltage values of this region calculated above as simulation inputs, and use numerical methods to calculate the electric field strength gradient in this region.

[0092] S143. Compare the electric field strength gradient in the target region with the theoretical calculated value of the onset of discharge in air, and based on the comparison result, determine whether there is a discharge risk in the target region; if so, take the region with a discharge risk as a weak point.

[0093] ​​Finally, when the electric field strength gradient in the target area is greater than the theoretically calculated value of the onset discharge in air, it indicates the existence of a discharge risk. Based on the discharge risk, this application assesses the discharge risk of this structure in the operating environment and identifies possible potential weak points in the motor slot.

[0094] As Figure 4 shown, this application mainly conducts risk identification from three positions, namely the main insulation position, the phase-to-phase insulation position, and the turn-to-turn insulation position. Figure 5 For the schematic diagrams of the main insulation position, the phase-to-phase insulation position, and the turn-to-turn insulation position in an embodiment of this application, please refer to Figure 5 to understand the main insulation position, the phase-to-phase insulation position, and the turn-to-turn insulation position described in this embodiment.

[0095] S150. Based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points, screen the potential weak points to obtain the insulation weak points in the motor slot.

[0096] The insulation performance data in this application includes breakdown voltage, heat resistance level, and dielectric constant.

[0097] Among them, the breakdown voltage can be calculated based on Paschen's Law. According to Paschen's Law, the minimum voltage U of the discharge process between two surfaces depends on the gas pressure p, the electrode spacing d, and the properties of the surrounding gas and the cathode material. The material properties are described by parameters A, B, and γ, where γ is the secondary electron emission coefficient of the cathode, and both A and B are constants obtained from experiments related to the type of surrounding gas. The Paschen curve of different cathode materials can be calculated using the Townsend equation:

[0098]

[0099] After obtaining the breakdown voltage, compare the voltage distribution characteristics of the potential weak points with the partial discharge inception voltage of the potential weak points. Among them, the partial discharge inception voltage is determined by the insulation performance data, and the insulation performance data includes heat resistance level and dielectric constant;

[0100] Regard the potential weak points with voltage greater than the partial discharge inception voltage as the insulation weak points in the electrode slot.

[0101] For the identified potentially weak areas, compare them with the performance data of the insulation system in the motor slots. The performance data of the insulation system may include the performance data of the insulation material (parameters such as heat resistance grade, dielectric constant, etc.). Through comparison, determine whether there are weak links in the insulation system of this area and whether optimization or strengthening is required. In this application, the partial discharge inception voltage under different insulation performance data can be simulated through experiments. Extract the voltage of the potentially weak point from the voltage distribution characteristics. If the voltage is greater than the partial discharge inception voltage (PDIV), it is an insulation weak point, and the value of PDIV is related to the ambient temperature and the material dielectric constant. If the calculated voltage value is higher than the PDIV value under the given conditions, this is the insulation weak point under these conditions.

[0102] Furthermore, in this application, the insulation structure can also be modified or adjusted in the simulation model. Using the same evaluation method, the discharge risk of different insulation structures under the same working conditions can be predicted, which can be used as a reference for insulation structure design, material selection, and margin selection.

[0103] Figure 6 It is a schematic diagram of the modification or adjustment process in an embodiment of this application. As Figure 6 shown, in this embodiment, based on the weak points located in the previous text, the insulation material and structure of the weak points can be obtained from the potential weak point model of the motor stator, and the electrical stress environment of the weak points under different operating conditions can be tested from the stator winding test system. Combine the insulation material and structure of the above weak points and the electrical stress environment to verify the insulation strength of the potential weak points. If the insulation strength is insufficient, change the parameters, thereby adjusting the insulation material and structure of the weak points, and re-verifying the insulation strength of the weak points. Repeating the above process can effectively repair the insulation weak points.

[0104] Finally, for the possible weak points, further verification and diagnosis are carried out using electrical tests (such as high voltage tests, partial discharge tests, etc.) or other detection means to ensure the reliable identification of the weak points.

[0105] A method for identifying weak points of insulation in the slots of an electric motor. An electric motor model is constructed based on the geometric structure of a concentrated winding electric motor; the electric motor model is subjected to simulation analysis to obtain the static parameters and dynamic parameters of the concentrated winding electric motor; a simplified circuit model of the concentrated winding electric motor is constructed, and the voltage distribution characteristics of the concentrated winding electric motor are determined based on the static parameters, dynamic parameters, and the simplified circuit model; discharge risk analysis is performed based on the voltage distribution characteristics extraction and the geometric structure of the concentrated winding electric motor to obtain potential weak points with discharge risk in the stator slots of the electric motor; the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points are used to screen the potential weak points to obtain the insulation weak points in the slots of the electric motor. This application is based on electromagnetic field modeling technology, can accurately identify the regions of electric stress concentration in the slots of the electric motor, and combined with the performance data of the insulation system, can efficiently judge the location and degree of the insulation weak points in the slots. This method can detect potential insulation problems in advance, thereby improving the operation safety and reliability of the electric motor and reducing the risk of electric motor failures.

[0106] As Figure 7 shown, this application also provides a system for identifying insulation weak points in the slots of an electric motor. The system is used to implement a method for identifying insulation weak points in the slots of an electric motor as described above. The system includes:

[0107] A model construction module for constructing an electric motor model based on the geometric structure of a concentrated winding electric motor;

[0108] A simulation analysis module for performing simulation analysis on the electric motor model to obtain the static parameters and dynamic parameters of the concentrated winding electric motor. Among them, the static parameters include the distributed capacitance of the winding in the electrostatic field, and the dynamic parameters include the AC resistance and AC inductance of the winding in the eddy current field;

[0109] A voltage distribution analysis module for constructing a simplified circuit model of the concentrated winding electric motor and determining the voltage distribution characteristics of the concentrated winding electric motor based on the static parameters, the dynamic parameters, and the simplified circuit model;

[0110] A preliminary weak point selection module for performing discharge risk analysis based on the voltage distribution characteristics extraction and the geometric structure of the concentrated winding electric motor to obtain potential weak points with discharge risk in the stator slots of the electric motor;

[0111] A weak point determination module for screening the potential weak points based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points to obtain the insulation weak points in the slots of the electric motor.

[0112] An identification system for weak points of insulation in the slots of an electric motor. The system constructs an electric motor model based on the geometric structure of a concentrated winding electric motor, conducts simulation analysis on the electric motor model to obtain the static parameters and dynamic parameters of the concentrated winding electric motor, constructs a simplified circuit model of the concentrated winding electric motor, and determines the voltage distribution characteristics of the concentrated winding electric motor based on the static parameters, dynamic parameters, and the simplified circuit model. Conducts discharge risk analysis based on the voltage distribution characteristics extraction and the geometric structure of the concentrated winding electric motor to obtain potential weak points with discharge risks in the stator slots of the electric motor. Screens the potential weak points by comparing the voltage distribution characteristics of the potential weak points with the insulation performance data of the potential weak points to obtain the weak points of insulation in the slots of the electric motor. This application is based on electromagnetic field modeling technology, can accurately identify the regions of electric stress concentration in the slots of the electric motor, and combined with the performance data of the insulation system, can efficiently determine the location and degree of the weak points of insulation in the slots. This method can detect potential insulation problems in advance, thereby improving the operating safety and reliability of the electric motor and reducing the risk of electric motor failures.

[0113] This embodiment also provides an electronic terminal, including: a processor and a memory;

[0114] The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory so that the terminal executes any of the methods in this embodiment.

[0115] For the computer-readable storage medium in this embodiment, those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the above method embodiments; and the aforementioned storage medium includes: various media such as ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0116] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver, and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication with each other. The memory is used to store a computer program, the communication interface is used for communication, and the processor and the transceiver are used to run the computer program so that the electronic terminal executes each step of the above method.

[0117] In this embodiment, the memory may include a random access memory (Random Access Memory, abbreviated as RAM), and may also include non-volatile memory, such as at least one disk memory.

[0118] The above-mentioned processor may be a general-purpose processor, including a central processing unit (CPU for short), a network processor (NP for short), etc.; it may also be a digital signal processor (DSP for short), an application specific integrated circuit (ASIC for short), a field-programmable gate array (FPGA for short), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0119] Another aspect of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor of the computer, the computer is enabled to execute the method as described above. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist alone without being assembled into the electronic device.

[0120] Another aspect of the present application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. A processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the methods provided in the above various embodiments.

[0121] The above embodiments are only preferred embodiments given to fully illustrate the present application, and the protection scope of the present application is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present application are all within the protection scope of the present application.

Claims

1. A method for identifying weak points of insulation in the slots of an electric machine, characterized in that, Including the steps of: Constructing a motor model based on the geometric structure of a concentrated winding motor; Performing simulation analysis on the motor model to obtain the static parameters and dynamic parameters of the concentrated winding motor, where the static parameters include the distributed capacitance of the winding in the electrostatic field, and the dynamic parameters include the AC resistance and AC inductance of the winding in the eddy current field; Constructing a simplified circuit model of the concentrated winding motor, and determining the voltage distribution characteristics of the concentrated winding motor based on the static parameters, the dynamic parameters, and the simplified circuit model; Performing a discharge risk analysis based on the voltage distribution characteristics extraction and the geometric structure of the concentrated winding motor to obtain potential weak points with discharge risks in the stator slots of the motor; Screening the potential weak points based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points to obtain the insulation weak points in the motor slots.

2. The identification method of insulation weak points in the motor slot according to claim 1, characterized in that, It also includes: Verifying the insulation weak points based on electrical tests to obtain reliable insulation weak points.

3. A method for identifying weak points of insulation in the slots of an electric machine according to claim 1, characterized in that, Performing simulation analysis on the motor model to obtain the static parameters of the concentrated winding motor, including: Calculating the capacitance of the stator slots of the motor model in the electrostatic field simulation environment to obtain a capacitance simulation result; Obtaining the measured result of the capacitance of the stator slots, verifying the capacitance simulation result based on the measured result, and using the capacitance simulation result that passes the verification as the static parameter of the concentrated winding motor.

4. A method for identifying weak points of insulation in the slots of an electric machine according to claim 1, characterized in that, Performing simulation analysis on the motor model to obtain the dynamic parameters of the concentrated winding motor, including: Measuring the oscillation frequency of the power supply output pulse in the eddy current field simulation environment, and calculating the AC resistance and AC inductance of the winding end at the oscillation frequency in the eddy current field simulation environment to obtain the dynamic parameters of the concentrated winding motor.

5. A method for identifying weak points of insulation in the slots of an electric machine according to claim 1, characterized in that, Constructing the simplified circuit model of the concentrated winding motor, including: Constructing a first simplified circuit model based on two series-adjacent coils of the same phase, where the first simplified circuit model is used to verify the uneven voltage distribution existing in the same coil; Constructing a second simplified circuit model of the full winding of the stator of the concentrated winding motor in the magnetic field with half of each coil as a unit, where the second simplified circuit model is used to verify the voltage distribution trend in the entire stator winding; Based on a group of 1 / 4 windings connected in Y shape, constructing a third simplified circuit model with a half-turn conductor as a unit, where the third simplified circuit model is used to verify the electrical stress distribution of each turn of the conductor in the magnetic field.

6. The identification method of insulation weak points in the motor slot according to claim 5, characterized in that, Determining the voltage distribution characteristics of the concentrated winding motor based on the static parameters, the dynamic parameters, and the simplified circuit model, including: Respectively constructing high-frequency equivalent circuits of the first simplified circuit model, the second simplified circuit model, and the third simplified circuit model; Establishing relationship equations of the currents and voltages of multiple nodes in the high-frequency equivalent circuit; Constructing a differential equation of the circuit based on the relationship equations of the currents and voltages of multiple nodes in the high-frequency equivalent circuit, and solving the differential equation to obtain the voltage distribution characteristics of the concentrated winding motor, where the voltage distribution characteristics include voltage values at multiple positions.

7. A method for identifying weak points of insulation in the slots of an electric machine according to claim 1, characterized in that, Based on the extraction of the voltage distribution characteristics and the geometric structure of the concentrated winding motor, a discharge risk analysis is carried out to obtain potential weak points with discharge risks in the stator slots of the motor, including: Based on the voltage distribution characteristics, a target area that meets the target conditions is extracted, where the target conditions are one or a combination of the following: the overall electric field strength in the area is greater than a preset strength threshold; the change rate of the electric field strength in the area is greater than a preset speed threshold; the local electrical stress in the area is greater than a preset stress threshold; Based on the voltage distribution characteristics, the voltage values at multiple positions in the target area are determined, and the voltage values at multiple positions in the target area are used as simulation inputs to calculate the electric field strength gradient of the target area; The electric field strength gradient of the target area is compared with the theoretical calculated value of the onset of discharge in air, and based on the comparison result, it is determined whether there is a discharge risk in the target area; if so, the area with a discharge risk is used as a weak point.

8. The method for identifying insulation weak points in the slots of an electric machine according to claim 1, characterized in that, Based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points, the potential weak points are screened to obtain insulation weak points in the motor slots, including: The voltage distribution characteristics of the potential weak points are compared with the partial discharge inception voltage of the potential weak points, where the partial discharge inception voltage is determined by the insulation performance data, and the insulation performance data includes the heat resistance grade and the dielectric constant; The potential weak points with voltages greater than the partial discharge inception voltage are used as insulation weak points in the electrode slots.

9. The identification method of insulation weak points in the slots of an electric machine according to claim 1, characterized in that, It further includes: Modify and adjust the insulation weak points, and after the modification and adjustment, return to constructing the motor model based on the geometric structure of the concentrated winding motor until there are no insulation weak points in the motor.

10. A recognition system for weak points of insulation in a motor slot, the system being used to implement a method for recognizing weak points of insulation in a motor slot as described in claim 1, characterized in that, The system includes: A model construction module for constructing a motor model based on the geometric structure of the concentrated winding motor; A simulation analysis module for performing a simulation analysis on the motor model to obtain the static parameters and dynamic parameters of the concentrated winding motor, where the static parameters include the distributed capacitance of the winding in the electrostatic field, and the dynamic parameters include the AC resistance and AC inductance of the winding in the eddy current field; A voltage distribution analysis module for constructing a simplified circuit model of the concentrated winding motor and determining the voltage distribution characteristics of the concentrated winding motor based on the static parameters, the dynamic parameters, and the simplified circuit model; A preliminary weak point selection module for performing a discharge risk analysis based on the extraction of the voltage distribution characteristics and the geometric structure of the concentrated winding motor to obtain potential weak points with discharge risks in the stator slots of the motor; A weak point determination module for screening the potential weak points based on the voltage distribution characteristics of the potential weak points and the insulation performance data of the potential weak points to obtain insulation weak points in the motor slots.

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