Analytical modeling method, device and computer equipment for electromagnetic performance of hydro-generator eccentric fault

Abstract

The present application relates to a kind of water turbine generator eccentric fault electromagnetic performance analytical modeling method, comprising: establishing electromagnetic field space model;Respectively establish eccentric fault under air gap region length function, air gap region length variation function caused by tooth slot structure and air gap region length variation function caused by salient pole structure.The air gap region length function under eccentric fault, air gap region length variation function caused by tooth slot structure and air gap region length variation function caused by salient pole structure are respectively expanded into Fourier series form.The analytical expression of air gap magnetic density is derived, and the analytical model of air gap magnetic density under eccentric fault is established.The counter electromotive force and electromagnetic torque of water turbine generator are further calculated.The analytical modeling method of water turbine generator eccentric fault electromagnetic performance provided by the present application can not only accurately calculate the air gap magnetic density distribution under normal and eccentric fault, but also analyze the contribution of each factor to air gap magnetic density and its periodic fluctuation characteristics.

Description

Technical Field

[0001] This invention relates to the field of hydro-generator technology, and in particular to an analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of hydro-generators with eccentric faults. Background Technology

[0002] Hydroelectric generators typically employ a salient-pole rotor structure to meet the requirements of low-speed, high-torque operation. Due to the characteristics of this structure, the air gap length is non-uniformly distributed along the circumference. Simultaneously, the presence of a slotted stator structure further exacerbates the spatial modulation effect of the air gap magnetic field. These factors combined result in significant periodic fluctuations in the air gap magnetic flux density, thus substantially affecting the generator's back electromotive force, electromagnetic torque, and operational stability. During actual operation, rotor eccentricity may occur, causing additional non-uniform changes in the air gap length with rotor angle, introducing additional harmonic components, leading to decreased generator performance and potentially increasing operational risks.

[0003] Currently, the main methods for calculating the air gap magnetic flux density distribution of hydro-generators include the finite element method (FEM) and analytical methods. The FEM can comprehensively consider complex structural features, material nonlinearities, and end effects, offering high computational accuracy. However, its modeling process is complex, computationally time-consuming, and highly dependent on mesh quality, making rapid calculation and online analysis difficult, thus limiting its application in engineering. In contrast, analytical methods offer significant advantages in computational efficiency, enabling rapid analysis of the air gap magnetic field characteristics by establishing a mathematical relationship between the generator's structural parameters and the magnetic field distribution.

[0004] Existing technologies for handling eccentric faults often employ empirical corrections or simplified single-factor models, lacking quantitative analytical modeling methods that can simultaneously consider the coupling effects of multiple factors. This leads to discrepancies between the calculated air gap magnetic flux density and the actual operating conditions. Furthermore, leakage flux is caused by factors such as the frame structure, end effects, and stator slotting, resulting in actual air gap magnetic flux density typically lower than theoretical calculations. Existing models generally lack effective leakage flux correction mechanisms, thus limiting their accuracy and applicability in engineering applications such as electromagnetic design optimization and fault diagnosis of hydro-generators. Therefore, current research primarily targets permanent magnet synchronous motors or simplified hydro-generator structures, failing to fully consider the multi-factor coupling characteristics caused by rotor salient pole effects, stator slotting effects, and eccentric air gaps, making it difficult to accurately reflect the distribution of actual air gap magnetic flux density. Summary of the Invention

[0005] This invention addresses the technical problem that existing methods for calculating the air gap magnetic flux density distribution of hydro-generators fail to adequately consider the rotor salient pole effect, stator cogging effect, and the multi-factor coupling characteristics caused by the eccentric air gap, making it difficult to accurately reflect the actual air gap magnetic flux density distribution. The invention provides an analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of hydro-generators under eccentric faults.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An analytical modeling method for the electromagnetic performance of a hydro-generator under eccentric faults includes: An electromagnetic field space model is established for a hydro-generator under eccentric fault conditions. Establish functions for the length of the air gap region under eccentric fault, the length variation function of the air gap region caused by the tooth groove structure, and the length variation function of the air gap region caused by the salient pole structure, respectively. The air gap region length function under eccentric fault, the air gap region length change function caused by tooth groove structure, and the air gap region length change function caused by salient pole structure are respectively expanded into Fourier series form. Based on the magnetomotive force distribution function and electromagnetic field space model under eccentric fault, the analytical expression of air gap magnetic flux density is derived, and an analytical model of air gap magnetic flux density under eccentric fault is established. Using the established analytical model of air gap magnetic flux density in eccentric faults, the back electromotive force and electromagnetic torque of the hydro-generator are calculated.

[0008] Furthermore, in this method, the electromagnetic field space model is expressed as: ; In the formula, δ is the total air gap region length; φ is the mechanical angle in the rotor coordinate system, expressed in radians; δ e Δδ represents the length of the air gap region under eccentric fault conditions. s Δδ represents the change in the length of the air gap region caused by the toothed structure. r This indicates the change in the length of the air gap region caused by the salient pole structure.

[0009] Furthermore, in this method, the air gap region length function under eccentric faults is: ; The function for the change in air gap region length caused by the toothed structure is: ; The function for the change in air gap region length caused by the salient pole structure is: ; In the formula, R s R is the radius of the inner surface of the stator; rθ is the radius of the rotor's outer surface; L is the distance from the center of the circle containing the rotor pole arc to the center of the rotor circle; i γ is the angle at which the center line of the i-th magnetic pole lies; i It is an angular difference, and satisfies γ i =|θ i -φ|;β i Let be the mechanical angle position corresponding to the center line of the i-th slot; b0 is the slot width; x satisfies the relationship x=|φ-β i |; e is the eccentricity, and R0 is the radius of the circle containing the rotor pole arc.

[0010] Furthermore, in this method, the air gap region length function under eccentric faults is expanded into a Fourier series form as follows: ; in, , , , ; O( ) indicates the existence of a constant C > 0, such that when When →0, it satisfies |O( )∣≤C ; The function representing the change in air gap region length caused by the toothed structure is: ; in, , , ; The function of the change in air gap region length caused by the salient pole structure, expanded into a Fourier series, is as follows: ; in, , , ; In the formula, τ is the slot pitch.

[0011] Furthermore, in this method, the analytical expression for the air gap magnetic flux density is: ; In the formula, N is the number of turns in the excitation winding of the motor, and i f denoted as the excitation current of the motor, and μ0 as the permeability of free space.

[0012] Furthermore, in this method, the back electromotive force of the hydro-generator is: ; The electromagnetic torque of the hydro-generator is: ; In the formula, ψ is the magnetic flux linkage, and E A E B E C I represents the back electromotive force of phases A, B, and C, respectively. A I B I C Let A, B, and C represent the phase currents of the three phases, respectively, and ω represent the rotor mechanical angular velocity.

[0013] This invention also provides an analytical modeling device for the electromagnetic performance of a hydro-generator under eccentric faults. This device is used to implement an analytical modeling method for the electromagnetic performance of a hydro-generator under eccentric faults, comprising: The spatial model building unit is used to establish an electromagnetic field spatial model for a hydro-generator under eccentric fault conditions. The function construction unit establishes the air gap region length function, the air gap region length change function caused by the tooth groove structure, and the air gap region length change function caused by the salient pole structure, respectively, based on the geometric relative position relationship between the rotor and stator under eccentric fault. The Fourier expansion unit expands the air gap region length function under eccentric fault, the air gap region length change function caused by the toothed structure, and the air gap region length change function caused by the salient pole structure into Fourier series form respectively. The air gap magnetic flux density calculation unit, based on the magnetomotive force distribution function and electromagnetic field space model under eccentric fault, derives the analytical expression of air gap magnetic flux density and establishes an analytical model of air gap magnetic flux density under eccentric fault. The back electromotive force and electromagnetic torque calculation unit uses the established analytical model of air gap magnetic flux density in eccentric faults to calculate the back electromotive force and electromagnetic torque of the hydro-generator.

[0014] Furthermore, in this device, the electromagnetic field spatial model is expressed as: ; In the formula, δ is the total air gap region length; φ is the mechanical angle in the rotor coordinate system, expressed in radians; δ e Δδ represents the length of the air gap region under eccentric fault conditions. s Δδ represents the change in the length of the air gap region caused by the toothed structure. r This indicates the change in the length of the air gap region caused by the salient pole structure.

[0015] Furthermore, the function for the air gap region length under eccentric fault conditions is: ; The function for the change in air gap region length caused by the toothed structure is: ; The function for the change in air gap region length caused by the salient pole structure is: ; In the formula, R s R is the radius of the inner surface of the stator; r θ is the radius of the rotor's outer surface; L is the distance from the center of the circle containing the rotor pole arc to the center of the rotor circle; i γ is the angle at which the center line of the i-th magnetic pole lies; i It is an angular difference, and satisfies γ i =|θ i -φ|;β i Let be the mechanical angle position corresponding to the center line of the i-th slot; b0 is the slot width; x satisfies the relationship x=|φ-β i |; e is the eccentricity, and R0 is the radius of the circle containing the rotor pole arc.

[0016] Furthermore, in this device, the function of the air gap region length under eccentric fault conditions is expanded into a Fourier series form as follows: ; in, , , , ; O( ) indicates the existence of a constant C > 0, such that when When →0, it satisfies |O( )∣≤C ; The function representing the change in air gap region length caused by the toothed structure is: ; in, , , ; The function of the change in air gap region length caused by the salient pole structure, expanded into a Fourier series, is as follows: ; in, , , ; In the formula, τ is the slot pitch.

[0017] Furthermore, in this device, the analytical expression for the air gap magnetic flux density is: ; In the formula, N is the number of turns in the excitation winding of the motor, and i f denoted as the excitation current of the motor, and μ0 as the permeability of free space.

[0018] Furthermore, in this device, the back electromotive force of the hydro-generator is: ; The electromagnetic torque of the hydro-generator is: ; In the formula, ψ is the magnetic flux linkage, and E A E B E C I represents the back electromotive force of phases A, B, and C, respectively. A I B I C Let A, B, and C represent the phase currents of the three phases, respectively, and ω represent the rotor mechanical angular velocity.

[0019] The present invention also provides a computer device, including a memory and one or more processors, wherein the memory stores executable code, and when the processor executes the executable code, it implements an analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric fault.

[0020] The present invention also provides a computer storage medium configured to store computer program instructions for executing an analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults.

[0021] The analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of a hydro-generator with eccentric faults provided by this invention have the following beneficial effects: The present invention provides an analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of a hydro-generator under eccentric faults. It represents the air gap length of the hydro-generator under eccentric faults as the superposition of three components: the length of the air gap region under eccentric faults, the change in the air gap region length caused by the toothed structure, and the change in the air gap region length caused by the salient pole structure. By mathematically modeling each component and solving them in a coupled manner, analytical calculation of the electromagnetic performance under eccentric faults is achieved. This method can not only accurately calculate the air gap magnetic flux density distribution under normal and eccentric fault conditions, but also analyze the contribution of each factor to the air gap magnetic flux density and its periodic fluctuation characteristics.

[0022] The analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of hydro-generators with eccentric faults provided by this invention can significantly improve the calculation efficiency of electromagnetic performance, avoid the high dependence of traditional finite element methods on mesh generation, and provide accurate analytical data for back electromotive force, electromagnetic torque, and eccentric fault analysis. It provides an efficient and reliable analytical calculation method for the study of air gap magnetic field characteristics, structural optimization, and eccentric fault diagnosis of hydro-generators, and has significant engineering application value. Attached Figure Description

[0023] Figure 1 A schematic diagram of a hydro-generator model provided for an embodiment of the present invention.

[0024] Figure 2 This is a comparison diagram of the air gap magnetic flux density of a hydro-generator under eccentric fault, obtained using the finite element method and the method provided in the embodiments of the present invention.

[0025] Figure 3 A comparison diagram of the back electromotive force of a hydro-generator obtained using the finite element method and the method provided in the embodiments of the present invention.

[0026] Figure 4 A comparison diagram of the electromagnetic torque of the hydro-generator obtained by the finite element method and the calculation method of this invention; Figure 5 This is a schematic diagram showing the positional relationship between the rotor and stator in an embodiment of the present invention. Detailed Implementation

[0027] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be thorough and complete.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0029] This invention provides an analytical modeling method for the electromagnetic performance of a hydro-generator under eccentric faults. (See also...) Figure 1This method employs a 10-pole, 84-slot hydro-generator, which includes a stator slot region 1, an air gap region 2, and a rotor salient pole region 3. The basic parameters of the hydro-generator are shown in Table 1. Taking this hydro-generator as an example, the analytical modeling method for the electromagnetic performance of a hydro-generator under eccentric fault conditions, provided by this invention, is used to calculate the air gap magnetic flux density, back electromotive force, and electromagnetic torque under eccentric fault conditions.

[0030]

[0031] Table 1 Specifically, the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults provided in this embodiment of the invention includes the following steps: Step S1. For the hydro-generator under eccentric fault, establish an electromagnetic field space model and divide the electromagnetic field space model into three parts: the length of the air gap region under eccentric fault, the change in the length of the air gap region caused by the toothed structure, and the change in the length of the air gap region caused by the salient pole structure.

[0032] The electromagnetic field spatial model in step S1 is expressed as follows: ; In the formula, δ is the total air gap region length, δ e Δδ represents the length of the air gap region under eccentric fault conditions. s Δδ represents the change in the length of the air gap region caused by the toothed structure. r This indicates the change in the length of the air gap region caused by the salient pole structure.

[0033] Step S2. Based on the geometric relative positional relationship between the rotor and stator under eccentric fault, establish the air gap region length function, the air gap region length variation function caused by the tooth groove structure, and the air gap region length variation function caused by the salient pole structure under eccentric fault.

[0034] In step S2, the function for the length of the air gap region under eccentric fault is: ; The function for the change in air gap region length caused by the toothed structure is: ; The function for the change in air gap region length caused by the salient pole structure is: ; In the formula, φ is the mechanical angle in the rotor coordinate system, expressed in radians; R s R is the radius of the inner surface of the stator; r θ is the radius of the rotor's outer surface; i γ is the angle at which the center line of the i-th magnetic pole lies; i It is an angular difference, and satisfies γ i =|θi -φ|;β i Let be the mechanical angle position corresponding to the center line of the i-th slot; b0 is the slot width; x satisfies the relationship x=|φ-β i |; R0 is the radius of the circle containing the rotor pole arc; see Figure 5 e is the eccentricity between the rotor center A1 and the stator center A2; L is the distance from the center A3 of the circle containing the rotor pole arc to the rotor center A1.

[0035] Step S3. Expand the air gap region length function under eccentric fault, the air gap region length change function caused by the tooth groove structure, and the air gap region length change function caused by the salient pole structure into Fourier series form respectively.

[0036] In step S3, Expanding the function of the air gap region length under eccentric fault into a Fourier series form is as follows: ; in, , , , ; In the formula, O( ) indicates the existence of a constant C > 0, such that when When →0, it satisfies |O( )∣≤C ; The function representing the change in air gap region length caused by the toothed structure is: ; in, , , ; The function of the change in air gap region length caused by the salient pole structure, expanded into a Fourier series, is as follows: ; in, , , , ; In the formula, τ is the slot pitch.

[0037] Step S4. Based on the magnetomotive force distribution function and electromagnetic field space model under eccentric fault, the analytical expression of air gap magnetic flux density is derived, and an analytical model of air gap magnetic flux density under eccentric fault is established.

[0038] The analytical expression for air gap magnetic flux density is: ; In the formula, N is the number of turns in the excitation winding of the motor, and i f denoted as the excitation current of the motor, and μ0 as the permeability of free space.

[0039] In step S4, a parameterized model of the hydro-generator is built using Matlab software. The formula in step S2 is solved, and the solution is substituted into the formula in step S1 to obtain the electromagnetic field space model. Finally, the formula in step S1 is substituted into the formula in step S4 to calculate the air gap magnetic flux density function and establish an analytical model of the air gap magnetic flux density in eccentric faults.

[0040] Step S5. Using the established analytical model of air gap magnetic flux density in eccentric faults, further calculate the back electromotive force and electromagnetic torque of the hydro-generator.

[0041] In step S5, the back electromotive force of the hydro-generator is: ; The electromagnetic torque of the hydro-generator is: ; In the formula, ψ is the magnetic flux linkage, and E A E B E C I represents the back electromotive force of phases A, B, and C respectively. A I B I C Let A, B, and C represent the phase currents of the three phases, respectively, and ω represent the rotor mechanical angular velocity.

[0042] Based on the 10-pole, 84-slot hydro-generator in this embodiment Figure 2 Table 2 shows a comparison of the air gap magnetic flux density under eccentric faults of hydro-generators obtained by using the finite element method and the analytical modeling method (analytical method) for the electromagnetic performance of hydro-generators under eccentric faults provided in this embodiment of the invention. It also compares the average values ​​of the air gap magnetic flux density amplitude calculated by the analytical modeling method (analytical method) for the electromagnetic performance of hydro-generators under eccentric faults under different magnetic poles provided in this embodiment of the invention with those calculated by the finite element method.

[0043]

[0044] Table 2 Figure 3 and Figure 4The figures show a comparison of back electromotive force and electromagnetic torque obtained using the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults provided in this embodiment of the invention and the finite element method. Table 3 compares the back electromotive force and electromagnetic torque data calculated by the analytical modeling method (analytical method) and the finite element method for the electromagnetic performance of a hydro-generator with eccentric faults provided in this embodiment of the invention.

[0045]

[0046] Table 3 Depend on Figures 2-4 As can be seen from Tables 2 and 3, the analytical calculation results of air gap magnetic flux density, back electromotive force, and electromagnetic torque under eccentric fault conditions provided by the method of this invention are in good agreement with the results of the finite element method, verifying the accuracy and feasibility of the method. Therefore, the method provided by this invention can be used for analytical calculation of electromagnetic performance modeling of hydro-generators under eccentric fault conditions. This method successfully constructs an analytical model of the electromagnetic performance of hydro-generators considering the coupling of multiple factors such as eccentricity, tooth cogging, and salient poles, avoiding the disadvantages of complex mesh generation and long calculation time of the finite element method, and achieving fast and accurate analytical calculation.

[0047] Example 2 This embodiment also provides an analytical modeling device for the electromagnetic performance of a hydro-generator with eccentric faults. This device is used to implement the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults described in Embodiment 1. It includes: a spatial model construction unit, a function construction unit, a Fourier expansion unit, an air gap magnetic flux density calculation unit, and a back electromotive force and electromagnetic torque calculation unit.

[0048] The spatial model building unit is configured to establish an electromagnetic field spatial model for a hydro-generator under eccentric faults. The electromagnetic field spatial model is divided into three parts: the length of the air gap region under eccentric faults, the change in the length of the air gap region caused by the toothed structure, and the change in the length of the air gap region caused by the salient pole structure.

[0049] The function building unit is configured to establish, based on the geometric relative positional relationship between the rotor and stator under eccentric fault, the air gap region length function caused by the tooth groove structure, and the air gap region length change function caused by the salient pole structure, respectively.

[0050] The Fourier expansion unit is configured to expand the air gap region length function under eccentric fault, the air gap region length change function caused by the tooth groove structure, and the air gap region length change function caused by the salient pole structure into Fourier series form, respectively.

[0051] The air gap magnetic flux density calculation unit is configured to derive the analytical expression of the air gap magnetic flux density based on the magnetomotive force distribution function and electromagnetic field space model under eccentric fault, and establish an analytical model of the air gap magnetic flux density under eccentric fault.

[0052] The back electromotive force and electromagnetic torque calculation unit is configured to calculate the back electromotive force and electromagnetic torque of the hydro-generator using the established analytical model of the air gap magnetic flux density in the eccentric fault.

[0053] Specifically, in this device, the electromagnetic field spatial model is expressed as: ; In the formula, δ is the total air gap region length; φ is the mechanical angle in the rotor coordinate system, expressed in radians; δ e Δδ represents the length of the air gap region under eccentric fault conditions. s Δδ represents the change in the length of the air gap region caused by the toothed structure. r This indicates the change in the length of the air gap region caused by the salient pole structure.

[0054] Specifically, the function for the air gap region length under eccentric fault is: ; The function for the change in air gap region length caused by the toothed structure is: ; The function for the change in air gap region length caused by the salient pole structure is: ; In the formula, R s R is the radius of the inner surface of the stator; r θ is the radius of the rotor's outer surface; L is the distance from the center of the circle containing the rotor pole arc to the center of the rotor circle; i γ is the angle at which the center line of the i-th magnetic pole lies; i It is an angular difference, and satisfies γ i =|θ i -φ|;β i Let be the mechanical angle position corresponding to the center line of the i-th slot; b0 is the slot width; x satisfies the relationship x=|φ-β i |; e is the eccentricity, and R0 is the radius of the circle containing the rotor pole arc.

[0055] Specifically, in this device, the function of the air gap region length under eccentric fault conditions is expanded into a Fourier series form as follows: ; in, , , , ; O( ) indicates the existence of a constant C > 0, such that when When →0, it satisfies |O( )∣≤C ; The function representing the change in air gap region length caused by the toothed structure is: ; in, , , ; The function of the change in air gap region length caused by the salient pole structure, expanded into a Fourier series, is as follows: ; in, , , ; In the formula, τ is the slot pitch.

[0056] Specifically, in this device, the analytical expression for the air gap magnetic flux density is: ; In the formula, N is the number of turns in the excitation winding of the motor, and i f denoted as the excitation current of the motor, and μ0 as the permeability of free space.

[0057] Specifically, in this device, the back electromotive force of the hydro-generator is: ; The electromagnetic torque of the hydro-generator is: ; In the formula, ψ is the magnetic flux linkage, and E A E B E C I represents the back electromotive force of phases A, B, and C, respectively. A I B I C Let A, B, and C represent the phase currents of the three phases, respectively, and ω represent the rotor mechanical angular velocity.

[0058] Example 3 This embodiment provides a computer device, including a memory and one or more processors. The memory stores executable code. When the processor executes the executable code, it implements the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults as provided in Embodiment 1.

[0059] Example 4 This embodiment provides a computer storage medium configured to store computer program instructions for executing the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults, as provided in Embodiment 1.

[0060] The analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of a hydro-generator with eccentric faults provided in this invention have the following beneficial effects: The analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of a hydro-generator under eccentric faults provided in this invention represent the air gap length of the hydro-generator under eccentric faults as the superposition of three components: the length of the air gap region under eccentric faults, the change in the air gap region length caused by the toothed structure, and the change in the air gap region length caused by the salient pole structure. By mathematically modeling each component and solving them in a coupled manner, analytical calculation of the electromagnetic performance under eccentric faults is achieved. This method can not only accurately calculate the air gap magnetic flux density distribution under normal and eccentric fault conditions, but also analyze the contribution of each factor to the air gap magnetic flux density and its periodic fluctuation characteristics.

[0061] The analytical modeling method, apparatus, and computer equipment for the electromagnetic performance of hydro-generators with eccentric faults provided in this invention can significantly improve the calculation efficiency of electromagnetic performance, avoid the high dependence of traditional finite element methods on mesh generation, and provide accurate analytical data for back electromotive force, electromagnetic torque, and eccentric fault analysis. It provides an efficient and reliable analytical calculation method for the study of air gap magnetic field characteristics, structural optimization, and eccentric fault diagnosis of hydro-generators, and has significant engineering application value.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An analytical modeling method for the electromagnetic performance of a hydro-generator under eccentric faults, characterized in that, include: An electromagnetic field space model is established for a hydro-generator under eccentric fault conditions. Establish functions for the length of the air gap region under eccentric fault, the length variation function of the air gap region caused by the tooth groove structure, and the length variation function of the air gap region caused by the salient pole structure, respectively. The air gap region length function under eccentric fault, the air gap region length change function caused by tooth groove structure, and the air gap region length change function caused by salient pole structure are respectively expanded into Fourier series form. Based on the magnetomotive force distribution function and electromagnetic field space model under eccentric fault, the analytical expression of air gap magnetic flux density is derived, and an analytical model of air gap magnetic flux density under eccentric fault is established. Using the established analytical model of air gap magnetic flux density in eccentric faults, the back electromotive force and electromagnetic torque of the hydro-generator are calculated. The analytical expression for the air gap magnetic flux density is: ； In the formula, N is the number of turns in the excitation winding of the motor, i f Let μ be the excitation current of the motor, and μ0 be the free permeability. The back electromotive force of the hydro-generator is: ； The electromagnetic torque of the hydro-generator is: ； In the formula, ψ is the magnetic flux linkage, and E A E B E C I represents the back electromotive force of phases A, B, and C, respectively. A I B I C Let A, B, and C represent the phase currents of the three phases, respectively, and ω represent the rotor mechanical angular velocity.

2. The analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 1, characterized in that, The electromagnetic field space model is expressed as: ； In the formula, δ is the total air gap region length; φ is the mechanical angle in the rotor coordinate system, expressed in radians; δ e Δδ represents the length of the air gap region under eccentric fault conditions. s Δδ represents the change in the length of the air gap region caused by the toothed structure. r This indicates the change in the length of the air gap region caused by the salient pole structure.

3. The analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 2, characterized in that, The function for the air gap region length under eccentric fault is: ； The function for the change in air gap region length caused by the toothed structure is: ； The function for the change in air gap region length caused by the salient pole structure is: ； In the formula, R s R is the radius of the inner surface of the stator; r θ is the radius of the rotor's outer surface; L is the distance from the center of the circle containing the rotor pole arc to the center of the rotor circle; i γ is the angle at which the center line of the i-th magnetic pole lies; i It is an angular difference, and satisfies γ i =|θ i -φ|; β i Let be the mechanical angle position corresponding to the center line of the i-th slot; b0 is the slot width; x satisfies the relationship x=|φ-β i |; e is the eccentricity, and R0 is the radius of the circle containing the rotor pole arc.

4. The analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 3, characterized in that, Expanding the function of the air gap region length under eccentric fault into a Fourier series form is as follows: ； in, ， ， ， ； O( ) indicates the existence of a constant C > 0, such that when When →0, it satisfies |O( )∣≤C ; The function representing the change in air gap region length caused by the toothed structure is: ； in, ， ， ； The function of the change in air gap region length caused by the salient pole structure, expanded into a Fourier series, is as follows: ； in, ， ， ； In the formula, τ is the slot pitch.

5. An analytical modeling device for the electromagnetic performance of a hydro-generator with eccentric fault, the device being used to implement the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric fault as described in claim 1, characterized in that, include: The spatial model building unit establishes an electromagnetic field spatial model for a hydro-generator under eccentric fault conditions. The function construction unit establishes the air gap region length function under eccentric fault, the air gap region length change function caused by tooth groove structure, and the air gap region length change function caused by salient pole structure, respectively. The Fourier expansion unit expands the air gap region length function under eccentric fault, the air gap region length change function caused by the toothed structure, and the air gap region length change function caused by the salient pole structure into Fourier series form respectively. The air gap magnetic flux density calculation unit, based on the magnetomotive force distribution function and electromagnetic field space model under eccentric fault, derives the analytical expression of air gap magnetic flux density and establishes an analytical model of air gap magnetic flux density under eccentric fault. The back electromotive force and electromagnetic torque calculation unit uses the established analytical model of air gap magnetic flux density in eccentric faults to calculate the back electromotive force and electromagnetic torque of the hydro-generator.

6. The analytical modeling device for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 5, characterized in that, The electromagnetic field space model is expressed as: ； In the formula, δ is the total air gap region length; φ is the mechanical angle in the rotor coordinate system, expressed in radians; δ e Δδ represents the length of the air gap region under eccentric fault conditions. s Δδ represents the change in the length of the air gap region caused by the toothed structure. r This indicates the change in the length of the air gap region caused by the salient pole structure.

7. The analytical modeling device for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 6, characterized in that, The function for the air gap region length under eccentric fault is: ； The function for the change in air gap region length caused by the toothed structure is: ； The function for the change in air gap region length caused by the salient pole structure is: ； In the formula, R s R is the radius of the inner surface of the stator; r θ is the radius of the rotor's outer surface; L is the distance from the center of the circle containing the rotor pole arc to the center of the rotor circle; i γ is the angle at which the center line of the i-th magnetic pole lies; i It is an angular difference, and satisfies γ i =|θ i -φ|; β i Let be the mechanical angle position corresponding to the center line of the i-th slot; b0 is the slot width; x satisfies the relationship x=|φ-β i |; e is the eccentricity, and R0 is the radius of the circle containing the rotor pole arc.

8. The analytical modeling device for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 7, characterized in that, Expanding the function of the air gap region length under eccentric fault into a Fourier series form is as follows: ； in, ， ， ， ； O( ) indicates the existence of a constant C > 0, such that when When →0, it satisfies |O( )∣≤C ; The function representing the change in air gap region length caused by the toothed structure is: ； in, ， ， ； The function of the change in air gap region length caused by the salient pole structure, expanded into a Fourier series, is as follows: ； in, ， ， ； In the formula, τ is the slot pitch.

9. The analytical modeling device for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 8, characterized in that, The analytical expression for the air gap magnetic flux density is: ； In the formula, N is the number of turns in the excitation winding of the motor, and i f denoted as the excitation current of the motor, and μ0 as the permeability of free space.

10. The analytical modeling device for the electromagnetic performance of a hydro-generator with eccentric faults according to claim 9, characterized in that, The back electromotive force of the hydro-generator is: ； The electromagnetic torque of the hydro-generator is: ； In the formula, ψ is the magnetic flux linkage, and E A E B E C I represents the back electromotive force of phases A, B, and C, respectively. A I B I C Let A, B, and C represent the phase currents of the three phases, respectively, and ω represent the rotor mechanical angular velocity.

11. A computer device comprising a memory and one or more processors, wherein the memory stores executable code, characterized in that... When the processor executes the executable code, it implements the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults as described in any one of claims 1-4.

12. A computer storage medium configured to store computer program instructions, characterized in that, The computer program instructions are used to execute the analytical modeling method for the electromagnetic performance of a hydro-generator with eccentric faults as described in any one of claims 1-4.

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