Field-circuit coupling simulation method and system of transformer, computer equipment and medium

Abstract

The invention relates to a field-circuit coupling simulation method and system of a transformer, computer equipment and a medium. According to the field-circuit coupling simulation method of the transformer, the magnetization curve of the to-be-tested transformer is fitted through a high-order interpolation method, so that the stability and the precision when a nonlinear finite element equation of an electromagnetic field of the transformer is solved are effectively improved, the stability of field-circuit coupling simulation of the transformer is ensured, the numerical oscillation phenomenon generated by field-circuit coupling simulation of the transformer is avoided, and the reliability of field-circuit coupling simulation of the transformer is improved. According to the method, the operation efficiency and reliability of transformer field-circuit coupling simulation can be improved, meanwhile, the calculation amount of nonlinear equation solving is effectively reduced, the solving efficiency is improved, and the efficiency of transformer field-circuit coupling simulation can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer simulation, and in particular to a method, system, computer equipment and medium for simulating field-circuit coupling of a transformer. Background Art

[0002] Transformer field-circuit coupling simulation can simulate the interactive influence of electromagnetic field characteristics and external circuit electromagnetic transient characteristics, and realize the synchronous calculation of transformer iron loss, copper loss and leakage magnetic loss with external circuit, which is beneficial to evaluate the operating efficiency and reliability of transformer and guide the design and optimization of transformer and circuit.

[0003] There are two main ways of transformer field-circuit coupling. The first is direct coupling, which is solved by establishing unified equations of circuit and electromagnetic field. However, the dimension of the equation is often high when solving the equation together. The iterative solution of high-dimensional nonlinear equations requires a large amount of calculation and low solution efficiency. The second is indirect coupling. The typical method is to use inductance for coupling. By solving the electromagnetic field equation, the equivalent inductance value that characterizes the magnetic field characteristics is obtained. When using inductance for indirect coupling, there are better simulation results in the near-linear region of the magnetic field, but when the magnetic field enters the saturation region, indirect coupling is prone to oscillation. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a field-circuit coupling simulation method of a transformer, the method comprising:

[0005] Based on the magnetization curve of the transformer to be tested, the magnetic induction intensity and magnetic field intensity of the transformer to be tested are numerically fitted using a high-order interpolation method to obtain the target functions of multiple segments of magnetic field intensity and magnetic induction intensity and the derivative function of each segment of the target function;

[0006] Based on the initial magnetic induction intensity of the transformer to be tested, the initial winding current, the multiple objective functions and the derivative function of each objective function, the field circuit of the transformer to be tested is coupled simulated using a preset finite element nonlinear equation of the electromagnetic field of the transformer to be tested to obtain initial simulation data;

[0007] Within a preset simulation time, a simulation result of the transformer to be tested is obtained based on the initial simulation data and the preset finite element nonlinear equation.

[0008] Optionally, obtaining the simulation result of the transformer to be tested based on the initial simulation data and the preset finite element nonlinear equation within a preset simulation time includes:

[0009] Using the magnetic induction intensity and winding current in the initial simulation data as the magnetic induction intensity and winding current of the transformer to be tested;

[0010] Based on the magnetic induction intensity and winding current of the transformer to be tested, multiple sections of objective functions and the derivative function of each section of the objective function, the field circuit of the transformer to be tested is coupled simulated by using the preset finite element nonlinear equation to obtain target simulation data;

[0011] If the current coupling simulation time is less than the preset simulation time, the target simulation data is used as the initial simulation data, and the field circuit of the transformer to be tested is continuously coupled to simulate until the current coupling simulation time reaches the preset simulation time;

[0012] If the current coupling simulation time reaches the preset simulation time, the simulation result of the transformer to be tested is determined based on the initial simulation data and a plurality of target simulation data obtained during the coupling simulation process.

[0013] Optionally, based on the magnetic induction intensity and winding current of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function, the field circuit of the transformer to be tested is coupled simulated by using the preset finite element nonlinear equation to obtain target simulation data, including:

[0014] Based on the magnetic induction intensity of the transformer to be tested, multiple sections of objective functions and the derivative function of each section of the objective function, the rate of change of the magnetic permeability with respect to the magnetic induction intensity is calculated;

[0015] Based on the rate of change of magnetic permeability with respect to magnetic induction intensity, the preset finite element nonlinear equation is updated to obtain the finite element nonlinear equation of the electromagnetic field of the transformer to be tested;

[0016] Based on the winding current of the transformer to be tested, the field circuit of the transformer to be tested is coupled simulated using the finite element nonlinear equation to obtain target simulation data.

[0017] Optionally, the calculation method of the change rate of the magnetic permeability with respect to the magnetic induction intensity satisfies the following formula:

[0018]

[0019] Among them, S(B) is the objective function of magnetic field strength and magnetic induction intensity, H represents the magnetic field strength of the transformer to be tested, S′(B) is the derivative function of the objective function, B is the magnetic induction intensity of the transformer to be tested, v is the magnetic permeability, is the rate of change of magnetic permeability with respect to magnetic induction intensity.

[0020] Optionally, based on the winding current of the transformer to be tested, using the finite element nonlinear equation to perform coupling simulation on the field circuit of the transformer to be tested to obtain target simulation data includes:

[0021] Based on the winding current of the transformer to be tested, the finite element nonlinear equation is simulated and solved to obtain the magnetic vector potential distribution;

[0022] Based on the magnetic vector potential distribution and the external circuit, construct a simulation circuit of the transformer to be tested;

[0023] A coupling simulation calculation is performed on the simulation circuit to obtain target simulation data.

[0024] Optionally, constructing a simulation circuit of the transformer to be tested based on the magnetic vector potential distribution and the external circuit includes:

[0025] Based on the magnetic vector potential distribution, the self-inductance and mutual inductance of the windings in the transformer to be tested are calculated;

[0026] Based on the self-inductance and mutual inductance of the windings in the transformer to be tested, the leakage inductance and the excitation inductance of the transformer to be tested are calculated;

[0027] Based on the leakage inductance and the magnetizing inductance of the transformer to be tested, circuit modeling is performed on the transformer to be tested to obtain a circuit model of the transformer to be tested;

[0028] Based on the circuit model of the transformer to be tested and the external circuit, a simulation circuit of the transformer to be tested is constructed.

[0029] Optionally, the calculation methods of the self-inductance and mutual inductance of the transformer to be tested satisfy the following formulas respectively:

[0030]

[0031] Where L is the self-inductance of the winding in the transformer to be tested, M ps is the mutual inductance between the primary winding and the secondary winding, M sp is the mutual inductance between the secondary winding and the primary winding, i is the winding current of the transformer to be tested, N is the number of turns of the transformer to be tested, l is the axial length of each winding, D is the integration area, ΔD is the winding area, S is the integration area, A is the magnetic vector potential distribution, the subscript p represents the primary side, and s represents the secondary side.

[0032] Optionally, the magnetization curve includes a plurality of discrete points;

[0033] Based on the magnetization curve of the transformer to be tested, the magnetic induction intensity and the magnetic field intensity of the transformer to be tested are numerically fitted by a high-order interpolation method to obtain the target functions of multiple segments of magnetic field intensity and magnetic induction intensity and the derivative function of each segment of the target function, including:

[0034] Based on multiple discrete points, the magnetic induction intensity and magnetic field intensity of each discrete point are numerically fitted using high-order interpolation method and preset boundary conditions to obtain multiple segments of objective functions and the derivative function of each segment of the objective function.

[0035] Optionally, each segment of the objective function and the derivative of each segment of the objective function satisfy the following formulas respectively:

[0036]

[0037] Among them, S j (B) is the objective function of the magnetic field strength and magnetic induction strength of the jth segment, H represents the magnetic field strength of the transformer to be tested, S′ j (B) is the derivative function of the jth segment objective function, B is the magnetic induction intensity of the transformer to be tested, M j 、M j-1 and M j+1 is a constant coefficient, h j =B j+1 -B j 、h j-1 =B j -B j-1 , B j and H j represents the magnetic induction intensity and magnetic field intensity of the jth discrete point on the magnetization curve, B j-1 and H j-1 represents the magnetic induction intensity and magnetic field intensity of the j-1th discrete point on the magnetization curve, B j+1 and H j+1 Represents the magnetic induction intensity and magnetic field intensity of the j+1th discrete point on the magnetization curve.

[0038] Based on the same inventive concept, the present invention also provides a field-circuit coupling simulation system for a transformer, the system comprising:

[0039] A function determination unit is used to perform numerical fitting on the magnetic induction intensity and magnetic field intensity of the transformer to be tested based on the magnetization curve of the transformer to be tested by using a high-order interpolation method to obtain a target function of multiple segments of magnetic field intensity and magnetic induction intensity and a derivative function of each segment of the target function;

[0040] A simulation data determination unit, configured to perform coupling simulation on the field circuit of the transformer to be tested using a preset finite element nonlinear equation of the electromagnetic field of the transformer to be tested based on the initial magnetic induction intensity of the transformer to be tested, the initial winding current, the multiple segments of the objective function and the derivative function of each segment of the objective function, so as to obtain initial simulation data;

[0041] The simulation result determination unit is used to obtain the simulation result of the transformer to be tested based on the initial simulation data and the preset finite element nonlinear equation within a preset simulation time.

[0042] Optionally, the simulation result determination unit includes:

[0043] A parameter determination module, used for taking the magnetic induction intensity and the winding current in the initial simulation data as the magnetic induction intensity and the winding current of the transformer to be tested;

[0044] A target simulation data determination module is used to perform coupled simulation on the field circuit of the transformer to be tested using the preset finite element nonlinear equation based on the magnetic induction intensity and winding current of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function to obtain target simulation data;

[0045] A cyclic coupling simulation module, for, if the current coupling simulation time is less than the preset simulation time, using the target simulation data as the initial simulation data, and continuing to perform coupling simulation on the field circuit of the transformer to be tested until the current coupling simulation time reaches the preset simulation time;

[0046] The simulation result determination module is used to determine the simulation result of the transformer to be tested based on the initial simulation data and multiple target simulation data obtained during the coupling simulation process if the current coupling simulation time reaches the preset simulation time.

[0047] Optionally, the target simulation data determination module includes:

[0048] A change rate determination submodule, used to calculate the change rate of magnetic permeability with respect to magnetic induction intensity based on the magnetic induction intensity of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function;

[0049] A nonlinear equation determination submodule, used to update the preset finite element nonlinear equation based on the rate of change of magnetic permeability with respect to magnetic induction intensity, so as to obtain the finite element nonlinear equation of the electromagnetic field of the transformer to be tested;

[0050] The target simulation data determination submodule is used to perform coupling simulation on the field circuit of the transformer to be tested based on the winding current of the transformer to be tested and using the finite element nonlinear equation to obtain target simulation data.

[0051] Optionally, the calculation method of the change rate of the magnetic permeability with respect to the magnetic induction intensity satisfies the following formula:

[0052]

[0053] Among them, S(B) is the objective function of magnetic field strength and magnetic induction intensity, H represents the magnetic field strength of the transformer to be tested, S′(B) is the derivative function of the objective function, B is the magnetic induction intensity of the transformer to be tested, v is the magnetic permeability, is the rate of change of magnetic permeability with respect to magnetic induction intensity.

[0054] Optionally, the target simulation data determination submodule is specifically used to:

[0055] Based on the winding current of the transformer to be tested, the finite element nonlinear equation is simulated and solved to obtain the magnetic vector potential distribution;

[0056] Based on the magnetic vector potential distribution and the external circuit, construct a simulation circuit of the transformer to be tested;

[0057] A coupling simulation calculation is performed on the simulation circuit to obtain target simulation data.

[0058] Optionally, the target simulation data determination submodule is specifically used to:

[0059] Based on the magnetic vector potential distribution, the self-inductance and mutual inductance of the windings in the transformer to be tested are calculated;

[0060] Based on the self-inductance and mutual inductance of the windings in the transformer to be tested, the leakage inductance and the excitation inductance of the transformer to be tested are calculated;

[0061] Based on the leakage inductance and the magnetizing inductance of the transformer to be tested, circuit modeling is performed on the transformer to be tested to obtain a circuit model of the transformer to be tested;

[0062] Based on the circuit model of the transformer to be tested and the external circuit, a simulation circuit of the transformer to be tested is constructed.

[0063] Optionally, the calculation methods of the self-inductance and mutual inductance of the transformer to be tested satisfy the following formulas respectively:

[0064]

[0065] Where L is the self-inductance of the winding in the transformer to be tested, M ps is the mutual inductance between the primary winding and the secondary winding, M sp is the mutual inductance between the secondary winding and the primary winding, i is the winding current of the transformer to be tested, N is the number of turns of the transformer to be tested, l is the axial length of each winding, D is the integration area, ΔD is the winding area, S is the integration area, A is the magnetic vector potential distribution, the subscript p represents the primary side, and s represents the secondary side.

[0066] Optionally, the magnetization curve includes a plurality of discrete points;

[0067] The function determination unit is specifically used for:

[0068] Based on multiple discrete points, the magnetic induction intensity and magnetic field intensity of each discrete point are numerically fitted using high-order interpolation method and preset boundary conditions to obtain multiple segments of objective functions and the derivative function of each segment of the objective function.

[0069] Optionally, each segment of the objective function and the derivative of each segment of the objective function satisfy the following formulas respectively:

[0070]

[0071] Among them, S j (B) is the objective function of the magnetic field strength and magnetic induction strength of the jth segment, H represents the magnetic field strength of the transformer to be tested, S′ j (B) is the derivative function of the jth segment objective function, B is the magnetic induction intensity of the transformer to be tested, M j 、M j-1 and M j+1 is a constant coefficient, h j =B j+1 -B j 、h j-1 =B j -B j-1 , B j and H j represents the magnetic induction intensity and magnetic field intensity of the jth discrete point on the magnetization curve, B j-1 and H j-1 represents the magnetic induction intensity and magnetic field intensity of the j-1th discrete point on the magnetization curve, B j+1 and H j+1 Represents the magnetic induction intensity and magnetic field intensity of the j+1th discrete point on the magnetization curve.

[0072] Based on the same inventive concept, the present invention also provides a computing device, including: one or more processors;

[0073] a processor for executing one or more programs;

[0074] When the one or more programs are executed by the one or more processors, the field-circuit coupling simulation method of a transformer as described above is implemented.

[0075] Based on the same inventive concept, the present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed, the field-circuit coupling simulation method of a transformer as described above is implemented.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The present invention provides a transformer field-circuit coupling simulation method, system, computer equipment and medium. The transformer field-circuit coupling simulation method fits the magnetization curve of the transformer to be tested by a high-order interpolation method, effectively improves the stability and accuracy of solving the nonlinear finite element equation of the transformer electromagnetic field, ensures the stability of the transformer field-circuit coupling simulation, avoids the numerical oscillation phenomenon of the transformer field-circuit coupling simulation, is conducive to improving the operation efficiency and reliability of the transformer field-circuit coupling simulation, and at the same time, effectively reduces the calculation amount of solving the nonlinear equation, improves the solution efficiency, and is conducive to improving the efficiency of the transformer field-circuit coupling simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 A flow chart of a transformer field-circuit coupling simulation method provided by the present invention;

[0079] Figure 2 A flow chart of another transformer field-circuit coupling simulation method provided by the present invention;

[0080] Figure 3 A flow chart of another transformer field-circuit coupling simulation method provided by the present invention;

[0081] Figure 4 A schematic diagram of a fitting result provided by the present invention;

[0082] Figure 5 A schematic diagram of transformer leakage inductance calculation results under a third-order spline interpolation fitting provided by the present invention;

[0083] Figure 6 A schematic diagram of transformer leakage inductance calculation results under low-order spline interpolation fitting provided by the present invention;

[0084] Figure 7 A block diagram of a transformer field-circuit coupling simulation system provided by the present invention;

[0085] Figure 8 A block diagram of a computer device provided by the present invention. DETAILED DESCRIPTION

[0086] Embodiment 1:

[0087] Figure 1 A flow chart of a transformer field-circuit coupling simulation method provided by the present invention, such as Figure 1 As shown, the method may include the following steps:

[0088] In step 101, based on the magnetization curve of the transformer to be tested, the magnetic induction intensity and the magnetic field intensity of the transformer to be tested are numerically fitted using a high-order interpolation method to obtain a target function of multiple segments of magnetic field intensity and magnetic induction intensity and a derivative function of each segment of the target function.

[0089] Wherein, the magnetization curve may include multiple discrete points, each discrete point may include the magnetic induction intensity and magnetic field intensity of the transformer to be tested, the magnetization curve may be obtained by simulating or experimenting on the transformer to be tested, the magnetization curve may also be called a BH (magnetic induction intensity-magnetic field intensity) magnetization curve, the high-order interpolation method may be an interpolation method with an order greater than or equal to 3 (i.e. ≥3 times), the high-order interpolation method may also be called a high-order spline interpolation method, and the objective function may also be called a fitting function.

[0090] The specific implementation method of this step can be that when the magnetization curve includes multiple discrete points, based on the multiple discrete points, the magnetic induction intensity and the magnetic field intensity of each discrete point are numerically fitted using a high-order interpolation method and preset boundary conditions to obtain multiple segments of objective functions and the derivative function of each segment of the objective function.

[0091] It should be noted that, the magnetic induction intensity and magnetic field intensity of each discrete point can be numerically fitted by using a high-order interpolation method and preset boundary conditions to obtain the derivative of each segment of the objective function, and then the derivative of each segment of the objective function can be integrated to obtain multiple segments of the objective function; or the magnetic induction intensity and magnetic field intensity of each discrete point can be numerically fitted by using a high-order interpolation method and preset boundary conditions to obtain multiple segments of the objective function, and then each segment of the objective function can be differentiated to obtain the derivative of each segment of the objective function. The preset boundary conditions can be selected as fixed boundary conditions, that is, the first-order derivative values ​​of the endpoints on both sides are respectively taken as the linear magnetic permeability v of the iron core line and saturation permeability v saturated Each segment of the objective function and the derivative of each segment of the objective function satisfy the following formulas:

[0092]

[0093] Among them, S j (B) is the objective function of the magnetic field strength and magnetic induction strength of the jth segment, H represents the magnetic field strength of the transformer to be tested, S′ j (B) is the derivative function of the jth segment objective function, B is the magnetic induction intensity of the transformer to be tested, M j 、M j-1 and M j+1 is a constant coefficient, h j =B j+1 -B j 、h j-1 =B j -B j-1 , B j and H j represents the magnetic induction intensity and magnetic field intensity of the jth discrete point on the magnetization curve, B j-1 and H j-1represents the magnetic induction intensity and magnetic field intensity of the j-1th discrete point on the magnetization curve, B j+1 and H j+1 Represents the magnetic induction intensity and magnetic field intensity of the j+1th discrete point on the magnetization curve.

[0094] For example, the BH magnetization curve has n discrete points. The high-order spline interpolation method can be used to numerically fit the transformer BH magnetization curve. Generally, the cubic spline interpolation method can be used to fit the n points to obtain the fitting function of n-1 segments. The j-th segment fitting function S j and its derivative function S′ j It can be expressed as formula (1).

[0095] In step 102, based on the initial magnetic induction intensity of the transformer to be tested, the initial winding current, the multiple objective functions and the derivative function of each objective function, the field circuit of the transformer to be tested is coupled simulated using the preset finite element nonlinear equation of the electromagnetic field of the transformer to be tested to obtain initial simulation data.

[0096] The initial simulation data may include the winding current and magnetic induction intensity of the transformer to be tested, and may also include the voltage and magnetic field intensity of the transformer to be tested.

[0097] It should be noted that the initial winding current of the transformer to be tested can be determined by the external circuit connected to the transformer to be tested, and the initial magnetic induction intensity of the transformer to be tested can be calculated based on the initial winding current. For example, the current input into the transformer to be tested by the external circuit can be used as the initial winding current of the transformer to be tested, and the initial magnetic induction intensity of the transformer to be tested can be calculated based on the initial winding current, the number of winding turns and the magnetic path length (usually equal to the outer circumference of the iron core). The initial winding current calculated by the external circuit (i.e., the external circuit) is used as the input excitation of the electromagnetic field of the transformer to be tested for finite element simulation (i.e., coupled simulation).

[0098] Optionally, after the initial simulation data is obtained, the initial simulation data may be stored.

[0099] In step 103, within a preset simulation time, a simulation result of the transformer to be tested is obtained based on the initial simulation data and the preset finite element nonlinear equation.

[0100] The simulation results may include the voltage, winding current, magnetic field strength, magnetic induction strength, etc. of the transformer to be tested.

[0101] It should be noted that within the preset simulation time (i.e., the current coupling simulation time is less than the preset simulation time), by updating the magnetic induction intensity and winding current of the transformer to be tested, a cyclic coupling simulation is performed on the field circuit of the transformer to be tested to obtain the simulation result of the transformer to be tested.

[0102] The field-circuit coupling simulation method of the transformer provided by the present invention can realize the field-circuit coupling simulation of the transformer. By fitting the magnetization characteristic curve of the transformer through a high-order interpolation method, the simulation accuracy of the transformer nonlinear finite element equation (i.e., the preset finite element nonlinear equation) can be effectively improved, thereby ensuring the stability of the transformer circuit model calculation when used for field-circuit coupling simulation.

[0103] Figure 2 A flow chart of another transformer field-circuit coupling simulation method provided by the present invention, such as Figure 2 As shown, Figure 1 The specific implementation of step 103 may include the following steps:

[0104] In step 1031, the magnetic induction intensity and the winding current in the initial simulation data are used as the magnetic induction intensity and the winding current of the transformer to be tested.

[0105] It should be noted that the magnetic induction intensity and winding current of the transformer to be tested are updated by taking the magnetic induction intensity and winding current in the initial simulation data as the magnetic induction intensity and winding current of the transformer to be tested.

[0106] In step 1032, based on the magnetic induction intensity and winding current of the transformer to be tested, multiple objective functions and the derivative function of each objective function, the field circuit of the transformer to be tested is coupled simulated using the preset finite element nonlinear equation to obtain target simulation data.

[0107] It should be noted that the preset finite element nonlinear equation can be updated based on the magnetic induction intensity of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function to obtain the finite element nonlinear equation; the winding current of the transformer to be tested is used as the input excitation of the electromagnetic field of the transformer to be tested, and the field circuit of the transformer to be tested is coupled and simulated using the finite element simulation finite element nonlinear equation to obtain the target simulation data.

[0108] In step 1033, if the current coupling simulation time is less than the preset simulation time, the target simulation data is used as the initial simulation data, and the field-circuit coupling simulation of the transformer to be tested is continued until the current coupling simulation time reaches the preset simulation time.

[0109] It should be noted that, when judging whether the current coupling simulation time is not less than the preset simulation time, if the current coupling simulation time is less than the preset simulation time, the target simulation data can be stored and used as the initial simulation data. After using the winding current and magnetic induction intensity in the initial simulation data to update the winding current and magnetic induction intensity of the transformer to be tested (that is, the magnetic induction intensity and winding current in the initial simulation data are used as the magnetic induction intensity and winding current of the transformer to be tested), the coupling simulation of the field circuit of the transformer to be tested is continued until the previous coupling simulation time reaches the preset simulation time.

[0110] In step 1034, if the current coupling simulation time reaches the preset simulation time, the simulation result of the transformer to be tested is determined based on the initial simulation data and a plurality of target simulation data obtained during the coupling simulation process.

[0111] It should be noted that if the current coupling simulation time reaches the preset simulation time, the stored initial simulation data and the multiple target simulation data obtained during the coupling simulation process will be used as the simulation results of the transformer to be tested, and the simulation results of the transformer to be tested will be output in a preset format. The preset format may be numerical results, image results or statistical data, etc.

[0112] In some embodiments, if the current coupling simulation time reaches the preset simulation time, the simulation data corresponding to the current coupling simulation time can be used as the simulation result of the transformer to be tested, and the simulation result of the transformer to be tested can be output according to a preset format.

[0113] Figure 3 A flow chart of another transformer field-circuit coupling simulation method provided by the present invention, such as Figure 3 As shown, Figure 2 The specific implementation of step 1032 may include the following steps:

[0114] In step S1, based on the magnetic induction intensity of the transformer to be tested, multiple sections of objective functions and the derivative function of each section of the objective function, the rate of change of the magnetic permeability with respect to the magnetic induction intensity is calculated.

[0115] The rate of change of magnetic permeability with respect to magnetic induction intensity can also be called the partial differential of magnetic permeability with respect to magnetic induction intensity.

[0116] It should be noted that the calculation method of the change rate of the magnetic permeability with respect to the magnetic induction intensity satisfies the following formula:

[0117]

[0118] Among them, S(B) is the objective function of magnetic field strength and magnetic induction intensity, H represents the magnetic field strength of the transformer to be tested, S′(B) is the derivative function of the objective function, B is the magnetic induction intensity of the transformer to be tested, v is the magnetic permeability, is the rate of change of magnetic permeability with respect to magnetic induction intensity.

[0119] In step S2, based on the rate of change of magnetic permeability with respect to magnetic induction intensity, the preset finite element nonlinear equation is updated to obtain the finite element nonlinear equation of the electromagnetic field of the transformer to be tested.

[0120] The preset finite element nonlinear equation may also be referred to as an electromagnetic field finite element nonlinear equation.

[0121] It should be noted that when solving the electromagnetic field finite element nonlinear equation, the partial differential of the magnetic permeability v with respect to the magnetic induction intensity is involved. The calculation of can be done through the objective function, the derivative of the objective function and formula (2) (i.e., using S j and its derivative function S′ j Calculate the partial differential of magnetic permeability with respect to magnetic induction intensity.

[0122] In step S3, based on the winding current of the transformer to be tested, the field-circuit coupling simulation of the transformer to be tested is performed using the finite element nonlinear equation to obtain target simulation data.

[0123] The specific implementation of this step may include simulating and solving the finite element nonlinear equation based on the winding current of the transformer to be tested to obtain the magnetic vector potential distribution; constructing a simulation circuit of the transformer to be tested based on the magnetic vector potential distribution and the external circuit; and performing coupled simulation calculations on the simulation circuit to obtain target simulation data.

[0124] The specific implementation methods of constructing the simulation circuit of the transformer to be tested based on the magnetic vector potential distribution and the external circuit may include: calculating the self-inductance and mutual inductance of the windings in the transformer to be tested based on the magnetic vector potential distribution; calculating the leakage inductance and excitation inductance of the transformer to be tested based on the self-inductance and mutual inductance of the windings in the transformer to be tested; performing circuit modeling on the transformer to be tested based on the leakage inductance and excitation inductance of the transformer to be tested to obtain the circuit model of the transformer to be tested; and constructing the simulation circuit of the transformer to be tested based on the circuit model of the transformer to be tested and the external circuit.

[0125] It should be noted that the distribution of the transformer magnetic vector potential A (i.e., magnetic vector potential distribution) can be obtained through simulation calculation of the electromagnetic field (i.e., finite element nonlinear equation). The calculation methods of the self-inductance and mutual inductance of the transformer to be tested respectively satisfy the following formulas:

[0126]

[0127] Where L is the self-inductance of the winding in the transformer to be tested, M ps is the mutual inductance between the primary winding and the secondary winding, M sp is the mutual inductance between the secondary winding and the primary winding, i is the winding current of the transformer to be tested, N is the number of turns of the transformer to be tested, l is the axial length of each winding, D is the integration area, ΔD is the winding area, S is the integration area, A is the magnetic vector potential distribution, the subscript p represents the primary side, and s represents the secondary side.

[0128] The present invention provides a transformer electromagnetic field and external circuit coupling simulation method (i.e., transformer field-circuit coupling simulation method), which uses a high-order interpolation method to fit the magnetization characteristic curve of the transformer, thereby ensuring the convergence of the iterative process of the electromagnetic field nonlinear equation and avoiding the numerical oscillation phenomenon caused by calculating the transformer's self-inductance and mutual inductance.

[0129] For example, a finite element model is established for a certain type of transformer, and the BH curve is fitted using third-order spline interpolation (i.e., cubic spline interpolation). The fitting results are as follows: Figure 4 As shown, the ordinate is the magnetic induction intensity B, the abscissa is the magnetic field intensity H, and the fitting result can be the objective function of multiple segments of magnetic field intensity and magnetic induction intensity, which is given by Figure 4 As shown, the fitting effect is good and the curve is smooth and continuous. The transformer leakage inductance calculated from the self-inductance and mutual inductance is as follows Figure 5 As shown in (the vertical axis is the transformer leakage inductance, and the horizontal axis is the coupling simulation time). If first-order linear interpolation is used, the transformer leakage inductance calculation will produce oscillation, such as Figure 6 As shown (the ordinate is the transformer leakage inductance, and the abscissa is the coupling simulation time), therefore, the high-order interpolation method is used to fit the magnetization characteristic curve of the transformer, which can ensure the stable calculation of the transformer leakage inductance, and thus ensure the stable calculation of the transformer circuit model.

[0130] In the above scheme, leakage inductance and excitation inductance can be calculated using self-inductance and mutual inductance, so as to model the circuit of the transformer and form a complete circuit model with the external circuit for circuit simulation. The winding current can be updated by the circuit simulation calculation results, and the updated winding current can be used again as input excitation to perform field-circuit coupling simulation.

[0131] When using electromagnetic fields to calculate transformer self-inductance and mutual inductance for field-circuit coupling simulation, it is necessary not only to calculate the magnetic vector potential simulation results under the primary and secondary currents of the transformer, but also to calculate the magnetic vector potential simulation results under small increments of primary and secondary currents. The fitting method of the nonlinear characteristics of the magnetization curve will affect the stability and accuracy of the electromagnetic field nonlinear equation calculation, affect the magnetic vector potential simulation results under small increments of current, and further affect the stability of the self-inductance and mutual inductance calculations.

[0132] The present invention relates to a simulation method for coupling an electromagnetic field and an external circuit of a transformer (i.e., a field-circuit coupling simulation method of a transformer). The method first performs high-order interpolation fitting on a nonlinear magnetization curve of a transformer core to ensure the continuity of the magnetization curve and its derivative, and then obtains the transformer self-inductance and mutual inductance according to the simulation calculation results of the electromagnetic field magnetic vector potential, and realizes the coupling simulation calculation of the electromagnetic field and the external circuit through the self-inductance and mutual inductance. In the present invention, the nonlinear magnetization curve adopts high-order interpolation fitting to avoid numerical oscillation in the electromagnetic field calculation process, improve the iterative calculation stability of the electromagnetic field, and improve the calculation accuracy and stability of the transformer self-inductance and mutual inductance, and finally realizes efficient and accurate transformer field-circuit coupling simulation.

[0133] Embodiment 2:

[0134] Figure 7 A block diagram of a transformer field-circuit coupling simulation system provided by the present invention, such as Figure 7 As shown, the system may include:

[0135] The function determination unit 701 is used to perform numerical fitting on the magnetic induction intensity and magnetic field intensity of the transformer to be tested based on the magnetization curve of the transformer to be tested by using a high-order interpolation method to obtain the target function of multiple segments of magnetic field intensity and magnetic induction intensity and the derivative function of each segment of the target function;

[0136] The simulation data determination unit 702 is used to perform coupling simulation on the field circuit of the transformer to be tested by using a preset finite element nonlinear equation of the electromagnetic field of the transformer to be tested based on the initial magnetic induction intensity of the transformer to be tested, the initial winding current, the multiple segments of the objective function and the derivative function of each segment of the objective function to obtain initial simulation data;

[0137] The simulation result determination unit 703 is used to obtain the simulation result of the transformer to be tested based on the initial simulation data and the preset finite element nonlinear equation within a preset simulation time.

[0138] Optionally, the simulation result determination unit 703 includes:

[0139] A parameter determination module, used for taking the magnetic induction intensity and the winding current in the initial simulation data as the magnetic induction intensity and the winding current of the transformer to be tested;

[0140] A target simulation data determination module is used to perform coupled simulation on the field circuit of the transformer to be tested using the preset finite element nonlinear equation based on the magnetic induction intensity and winding current of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function to obtain target simulation data;

[0141] A cyclic coupling simulation module, for, if the current coupling simulation time is less than the preset simulation time, using the target simulation data as the initial simulation data, and continuing to perform coupling simulation on the field circuit of the transformer to be tested until the current coupling simulation time reaches the preset simulation time;

[0142] The simulation result module is used to determine the simulation result of the transformer to be tested based on the initial simulation data and multiple target simulation data obtained during the coupling simulation process if the current coupling simulation time reaches the preset simulation time.

[0143] Optionally, the target simulation data determination module includes:

[0144] A change rate determination submodule, used to calculate the change rate of magnetic permeability with respect to magnetic induction intensity based on the magnetic induction intensity of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function;

[0145] A nonlinear equation determination submodule, used to update the preset finite element nonlinear equation based on the rate of change of magnetic permeability with respect to magnetic induction intensity, so as to obtain the finite element nonlinear equation of the electromagnetic field of the transformer to be tested;

[0146] The target simulation data determination submodule is used to perform coupling simulation on the field circuit of the transformer to be tested based on the winding current of the transformer to be tested and using the finite element nonlinear equation to obtain target simulation data.

[0147] Optionally, the calculation method of the change rate of the magnetic permeability with respect to the magnetic induction intensity satisfies the following formula:

[0148]

[0149] Among them, S(B) is the objective function of magnetic field strength and magnetic induction intensity, H represents the magnetic field strength of the transformer to be tested, S′(B) is the derivative function of the objective function, B is the magnetic induction intensity of the transformer to be tested, v is the magnetic permeability, is the rate of change of magnetic permeability with respect to magnetic induction intensity.

[0150] Optionally, the target simulation data determination submodule is specifically used to:

[0151] Based on the winding current of the transformer to be tested, the finite element nonlinear equation is simulated and solved to obtain the magnetic vector potential distribution;

[0152] Based on the magnetic vector potential distribution and the external circuit, construct a simulation circuit of the transformer to be tested;

[0153] A coupling simulation calculation is performed on the simulation circuit to obtain target simulation data.

[0154] Optionally, the target simulation data determination submodule is specifically used to:

[0155] Based on the magnetic vector potential distribution, the self-inductance and mutual inductance of the windings in the transformer to be tested are calculated;

[0156] Based on the self-inductance and mutual inductance of the windings in the transformer to be tested, the leakage inductance and the excitation inductance of the transformer to be tested are calculated;

[0157] Based on the leakage inductance and the magnetizing inductance of the transformer to be tested, circuit modeling is performed on the transformer to be tested to obtain a circuit model of the transformer to be tested;

[0158] Based on the circuit model of the transformer to be tested and the external circuit, a simulation circuit of the transformer to be tested is constructed.

[0159] Optionally, the calculation methods of the self-inductance and mutual inductance of the transformer to be tested satisfy the following formulas respectively:

[0160]

[0161] Where L is the self-inductance of the winding in the transformer to be tested, M ps is the mutual inductance between the primary winding and the secondary winding, M sp is the mutual inductance between the secondary winding and the primary winding, i is the winding current of the transformer to be tested, N is the number of turns of the transformer to be tested, l is the axial length of each winding, D is the integration area, ΔD is the winding area, S is the integration area, A is the magnetic vector potential distribution, the subscript p represents the primary side, and s represents the secondary side.

[0162] Optionally, the magnetization curve includes a plurality of discrete points;

[0163] The function determination unit 701 is specifically configured to:

[0164] Based on multiple discrete points, the magnetic induction intensity and magnetic field intensity of each discrete point are numerically fitted using high-order interpolation method and preset boundary conditions to obtain multiple segments of objective functions and the derivative function of each segment of the objective function.

[0165] Optionally, each segment of the objective function and the derivative of each segment of the objective function satisfy the following formulas respectively:

[0166]

[0167] Among them, S j (B) is the objective function of the magnetic field strength and magnetic induction strength of the jth segment, H represents the magnetic field strength of the transformer to be tested, S′ j (B) is the derivative function of the jth segment objective function, B is the magnetic induction intensity of the transformer to be tested, M j 、M j-1 and Mj+1 is a constant coefficient, h j =B j+1 -B j 、h j-1 =B j -B j-1 , B j and H j represents the magnetic induction intensity and magnetic field intensity of the jth discrete point on the magnetization curve, B j-1 and H j-1 represents the magnetic induction intensity and magnetic field intensity of the j-1th discrete point on the magnetization curve, B j+1 and H j+1 Represents the magnetic induction intensity and magnetic field intensity of the j+1th discrete point on the magnetization curve.

[0168] Embodiment 3:

[0169] Based on the same inventive concept, the present invention also provides a computer device, such as Figure 8 As shown, the computer device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits, or other processors.

[0170] (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in a computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of a field-circuit coupling simulation method of a transformer in the above-mentioned embodiment.

[0171] Embodiment 4:

[0172] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in a computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of a field-circuit coupling simulation method of a transformer in the above embodiment.

[0173] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0174] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0175] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1A function specified in one or more boxes.

[0176] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0177] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A transformer field-circuit coupling simulation method, characterized in that: The method comprises: Based on the magnetization curve of the transformer to be tested, the magnetic induction intensity and magnetic field intensity of the transformer to be tested are numerically fitted using a high-order interpolation method to obtain the target functions of multiple segments of magnetic field intensity and magnetic induction intensity and the derivative function of each segment of the target function; Based on the initial magnetic induction intensity of the transformer to be tested, the initial winding current, the multiple objective functions and the derivative function of each objective function, the field circuit of the transformer to be tested is coupled simulated using a preset finite element nonlinear equation of the electromagnetic field of the transformer to be tested to obtain initial simulation data; Within a preset simulation time, a simulation result of the transformer to be tested is obtained based on the initial simulation data and the preset finite element nonlinear equation.

2. The method according to claim 1, characterized in that The step of obtaining the simulation result of the transformer to be tested based on the initial simulation data and the preset finite element nonlinear equation within the preset simulation time includes: Using the magnetic induction intensity and the winding current in the initial simulation data as the magnetic induction intensity and the winding current of the transformer to be tested; Based on the magnetic induction intensity and winding current of the transformer to be tested, multiple sections of objective functions and the derivative function of each section of the objective function, the field circuit of the transformer to be tested is coupled simulated by using the preset finite element nonlinear equation to obtain target simulation data; If the current coupling simulation time is less than the preset simulation time, the target simulation data is used as the initial simulation data, and the field circuit of the transformer to be tested is continuously coupled to simulate until the current coupling simulation time reaches the preset simulation time; If the current coupling simulation time reaches the preset simulation time, the simulation result of the transformer to be tested is determined based on the initial simulation data and a plurality of target simulation data obtained during the coupling simulation process.

3. The method according to claim 2, characterized in that Based on the magnetic induction intensity and winding current of the transformer to be tested, multiple sections of objective functions and the derivative function of each section of the objective function, the field circuit of the transformer to be tested is coupled simulated by using the preset finite element nonlinear equation to obtain target simulation data, including: Based on the magnetic induction intensity of the transformer to be tested, multiple sections of objective functions and the derivative function of each section of the objective function, the rate of change of the magnetic permeability with respect to the magnetic induction intensity is calculated; Based on the rate of change of magnetic permeability with respect to magnetic induction intensity, the preset finite element nonlinear equation is updated to obtain the finite element nonlinear equation of the electromagnetic field of the transformer to be tested; Based on the winding current of the transformer to be tested, the field circuit of the transformer to be tested is coupled simulated using the finite element nonlinear equation to obtain target simulation data.

4. The method according to claim 3, characterized in that The calculation method of the change rate of the magnetic permeability with respect to the magnetic induction intensity satisfies the following formula: Among them, S(B) is the objective function of magnetic field strength and magnetic induction intensity, H represents the magnetic field strength of the transformer to be tested, S′(B) is the derivative function of the objective function, B is the magnetic induction intensity of the transformer to be tested, v is the magnetic permeability, is the rate of change of magnetic permeability with respect to magnetic induction intensity.

5. The method according to claim 3, characterized in that: The method of performing coupling simulation on the field circuit of the transformer to be tested by using the finite element nonlinear equation based on the winding current of the transformer to be tested to obtain target simulation data includes: Based on the winding current of the transformer to be tested, the finite element nonlinear equation is simulated and solved to obtain the magnetic vector potential distribution; Based on the magnetic vector potential distribution and the external circuit, construct a simulation circuit of the transformer to be tested; A coupling simulation calculation is performed on the simulation circuit to obtain target simulation data.

6. The method according to claim 5, characterized in that The step of constructing a simulation circuit of the transformer to be tested based on the magnetic vector potential distribution and the external circuit includes: Based on the magnetic vector potential distribution, the self-inductance and mutual inductance of the windings in the transformer to be tested are calculated; Based on the self-inductance and mutual inductance of the windings in the transformer to be tested, the leakage inductance and the excitation inductance of the transformer to be tested are calculated; Based on the leakage inductance and the magnetizing inductance of the transformer to be tested, circuit modeling is performed on the transformer to be tested to obtain a circuit model of the transformer to be tested; Based on the circuit model of the transformer to be tested and the external circuit, a simulation circuit of the transformer to be tested is constructed.

7. The method according to claim 6, characterized in that The calculation methods of the self-inductance and mutual inductance of the transformer to be tested respectively satisfy the following formulas: Where L is the self-inductance of the winding in the transformer to be tested, M ps is the mutual inductance between the primary winding and the secondary winding, M sp is the mutual inductance between the secondary winding and the primary winding, i is the winding current of the transformer to be tested, N is the number of turns of the transformer to be tested, l is the axial length of each winding, D is the integration area, ΔD is the winding area, S is the integration area, A is the magnetic vector potential distribution, the subscript p represents the primary side, and s represents the secondary side.

8. The method according to any one of claims 1 to 7, characterized in that: The magnetization curve includes a plurality of discrete points; Based on the magnetization curve of the transformer to be tested, the magnetic induction intensity and the magnetic field intensity of the transformer to be tested are numerically fitted by a high-order interpolation method to obtain the target functions of multiple segments of magnetic field intensity and magnetic induction intensity and the derivative function of each segment of the target function, including: Based on multiple discrete points, the magnetic induction intensity and magnetic field intensity of each discrete point are numerically fitted using high-order interpolation method and preset boundary conditions to obtain multiple segments of objective functions and the derivative function of each segment of the objective function.

9. The method according to claim 6, characterized in that Each segment of the objective function and the derivative function of each segment of the objective function satisfy the following formulas: Among them, S j (B) is the objective function of the magnetic field strength and magnetic induction intensity of the jth segment, H represents the magnetic field strength of the transformer to be tested, S j ′(B) is the derivative function of the jth segment objective function, B is the magnetic induction intensity of the transformer to be tested, M j 、M j-1 and M j+1 is a constant coefficient, h j =B j+1 -B j 、h j-1 =B j -B j-1 , B j and H j represents the magnetic induction intensity and magnetic field intensity of the jth discrete point on the magnetization curve, B j-1 and H j-1 represents the magnetic induction intensity and magnetic field intensity of the j-1th discrete point on the magnetization curve, B j+1 and H j+1 Represents the magnetic induction intensity and magnetic field intensity of the j+1th discrete point on the magnetization curve.

10. A transformer field-circuit coupling simulation system, characterized in that: The system comprises: A function determination unit is used to perform numerical fitting on the magnetic induction intensity and magnetic field intensity of the transformer to be tested based on the magnetization curve of the transformer to be tested by using a high-order interpolation method to obtain a target function of multiple segments of magnetic field intensity and magnetic induction intensity and a derivative function of each segment of the target function; A simulation data determination unit, configured to perform coupling simulation on the field circuit of the transformer to be tested using a preset finite element nonlinear equation of the electromagnetic field of the transformer to be tested based on the initial magnetic induction intensity of the transformer to be tested, the initial winding current, the multiple segments of the objective function and the derivative function of each segment of the objective function, so as to obtain initial simulation data; The simulation result determination unit is used to obtain the simulation result of the transformer to be tested based on the initial simulation data and the preset finite element nonlinear equation within a preset simulation time.

11. The system according to claim 10, characterized in that The simulation result determination unit comprises: A parameter determination module, used for taking the magnetic induction intensity and the winding current in the initial simulation data as the magnetic induction intensity and the winding current of the transformer to be tested; A target simulation data determination module is used to perform coupled simulation on the field circuit of the transformer to be tested using the preset finite element nonlinear equation based on the magnetic induction intensity and winding current of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function to obtain target simulation data; A cyclic coupling simulation module, for, if the current coupling simulation time is less than the preset simulation time, using the target simulation data as the initial simulation data, and continuing to perform coupling simulation on the field circuit of the transformer to be tested until the current coupling simulation time reaches the preset simulation time; The simulation result determination module is used to determine the simulation result of the transformer to be tested based on the initial simulation data and multiple target simulation data obtained during the coupling simulation process if the current coupling simulation time reaches the preset simulation time.

12. The system according to claim 11, characterized in that The target simulation data determination module comprises: A change rate determination submodule, used to calculate the change rate of magnetic permeability with respect to magnetic induction intensity based on the magnetic induction intensity of the transformer to be tested, multiple segments of objective functions and the derivative function of each segment of the objective function; A nonlinear equation determination submodule, used to update the preset finite element nonlinear equation based on the rate of change of magnetic permeability with respect to magnetic induction intensity, so as to obtain the finite element nonlinear equation of the electromagnetic field of the transformer to be tested; The target simulation data determination submodule is used to perform coupling simulation on the field circuit of the transformer to be tested based on the winding current of the transformer to be tested and using the finite element nonlinear equation to obtain target simulation data.

13. The system according to claim 12, characterized in that The calculation method of the change rate of the magnetic permeability with respect to the magnetic induction intensity satisfies the following formula: Among them, S(B) is the objective function of magnetic field strength and magnetic induction intensity, H represents the magnetic field strength of the transformer to be tested, S′(B) is the derivative function of the objective function, B is the magnetic induction intensity of the transformer to be tested, v is the magnetic permeability, is the rate of change of magnetic permeability with respect to magnetic induction intensity.

14. The system according to claim 12, characterized in that The target simulation data determination submodule is specifically used for: Based on the winding current of the transformer to be tested, the finite element nonlinear equation is simulated and solved to obtain the magnetic vector potential distribution; Based on the magnetic vector potential distribution and the external circuit, construct a simulation circuit of the transformer to be tested; A coupling simulation calculation is performed on the simulation circuit to obtain target simulation data.

15. The system according to claim 14, characterized in that The target simulation data determination submodule is specifically used for: Based on the magnetic vector potential distribution, the self-inductance and mutual inductance of the windings in the transformer to be tested are calculated; Based on the self-inductance and mutual inductance of the windings in the transformer to be tested, the leakage inductance and the excitation inductance of the transformer to be tested are calculated; Based on the leakage inductance and the magnetizing inductance of the transformer to be tested, circuit modeling is performed on the transformer to be tested to obtain a circuit model of the transformer to be tested; Based on the circuit model of the transformer to be tested and the external circuit, a simulation circuit of the transformer to be tested is constructed.

16. The system according to claim 15, characterized in that The calculation methods of the self-inductance and mutual inductance of the transformer to be tested respectively satisfy the following formulas: Where L is the self-inductance of the winding in the transformer to be tested, M ps is the mutual inductance between the primary winding and the secondary winding, M sp is the mutual inductance between the secondary winding and the primary winding, i is the winding current of the transformer to be tested, N is the number of turns of the transformer to be tested, l is the axial length of each winding, D is the integration area, ΔD is the winding area, S is the integration area, A is the magnetic vector potential distribution, the subscript p represents the primary side, and s represents the secondary side.

17. The system according to any one of claims 10 to 16, characterized in that: The magnetization curve includes a plurality of discrete points; The function determination unit is specifically used for: Based on multiple discrete points, the magnetic induction intensity and magnetic field intensity of each discrete point are numerically fitted using high-order interpolation method and preset boundary conditions to obtain multiple segments of objective functions and the derivative function of each segment of the objective function.

18. The system according to claim 15, characterized in that Each segment of the objective function and the derivative function of each segment of the objective function satisfy the following formulas: Among them, S j (B) is the objective function of the magnetic field strength and magnetic induction strength of the jth segment, H represents the magnetic field strength of the transformer to be tested, S′ j (B) is the derivative function of the jth segment objective function, B is the magnetic induction intensity of the transformer to be tested, M j 、M j-1 and M j+1 is a constant coefficient, h j =B j+1 -B j 、h j-1 =B j -B j-1 , B j and H j represents the magnetic induction intensity and magnetic field intensity of the jth discrete point on the magnetization curve, B j-1 and H j-1 represents the magnetic induction intensity and magnetic field intensity of the j-1th discrete point on the magnetization curve, B j+1 and H j+1 Represents the magnetic induction intensity and magnetic field intensity of the j+1th discrete point on the magnetization curve.

19. A computer device, characterized in that: include: one or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, the field-circuit coupling simulation method of the transformer according to any one of claims 1 to 9 is implemented.

20. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the field-circuit coupling simulation method of the transformer as claimed in any one of claims 1 to 9 is implemented.

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