Method and system for calculating transient current waveform of multiphase air-core pulse generator

Abstract

The present invention belongs to the technical field of pulse generators, and specifically relates to a method and system for calculating the transient current waveform of a multi-phase air-core pulse generator, aiming to solve the problem that the prior art cannot realize the calculation of the transient current waveform of a multi-phase air-core pulse generator. The present invention includes: establishing a voltage matrix equation of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in a natural coordinate system; integrating the left and right sides of the equation by time t to obtain the corresponding non-homogeneous linear integral equation; solving the non-homogeneous linear integral equation by Gaussian elimination iteration to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator. The present invention converts the complex differential equation in the calculation of the transient current waveform of the multi-phase air-core pulse generator into the solution of a linear integral equation group, and obtains an approximate expression for the transient current waveform of the motor, which not only reduces the amount of calculation, but also provides theoretical guidance for the selection of the discharge trigger angle and the shaping of the discharge current.

Description

Background Art

[0002] The pulse generator is a special synchronous generator that uses the principle of magnetic flux compression to make the motor release very large transient currents. The air-core pulse generator does not have a compensation winding, but uses non-ferromagnetic materials to make the rotor. Compared with the iron-core motor, the inductance of the armature winding is already very small. In addition, when the armature winding of the air-core pulse generator is discharged, the excitation current will flow through the diode, and there is coupling between the armature winding and the excitation winding, which further reduces the inductance of the armature winding. Therefore, although the air-core motor does not have a special compensation winding, it will also release an ideal pulse current.

[0003] The multi-phase pulse generator generates direct current to supply power to the load through thyristor rectification. The desired current shape can be obtained by adjusting the trigger angle of each phase thyristor. Due to the special air-core topology of the multi-phase pulse generator and the electromagnetic coupling between multiple current pulses, its discharge process is very complicated. On the basis of establishing the mathematical model of the pulse generator, its current expression is difficult to directly derive analytically.

[0004] At the current research level, the trigger angle can be adjusted by trial and error in the simulation system to obtain the desired current shape. However, there is still a need for a direct method to determine the trigger angle to obtain the desired current waveform. This requires understanding the discharge process of the multi-phase pulse AC generator and obtaining the calculation formula for its discharge current.

[0005] In the prior art, the winding current expressions of single-phase and two-phase pulse generators, as well as the approximate expression of the peak current of each phase armature winding of a four-phase motor have been obtained. However, the analytical solution method for the approximate expression of the excitation current and armature current of a multi-phase pulse generator is still imperfect, and it is impossible to calculate the transient current waveform of a multi-phase air-core pulse generator. Summary of the invention

[0006] In order to solve the above-mentioned problem in the prior art, that is, the problem that the prior art cannot realize the transient current waveform calculation of the multi-phase air-core pulse generator, the present invention provides a method for calculating the transient current waveform of the multi-phase air-core pulse generator, the method comprising:

[0007] Establishing voltage matrix equations of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in a natural coordinate system;

[0008] Integrate the left and right sides of the voltage matrix equation with respect to time t to obtain a corresponding non-homogeneous linear integral equation;

[0009] The non-homogeneous linear integral equation is solved iteratively by Gaussian elimination method to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0010] In some preferred embodiments, the voltage matrix equations of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in the natural coordinate system are expressed as:

[0011]

[0012] Among them, M rs ,r=1,2,…,n,s=1,2,…,n represents the mutual inductance between the rth phase armature winding and the Sth phase armature winding of the multi-phase air-core pulse generator, L represents the self-inductance of the armature winding of the multi-phase air-core pulse generator, L f represents the self-inductance of the excitation winding of the multi-phase air-core pulse generator, M represents the maximum mutual inductance of the excitation winding and armature winding of the multi-phase air-core pulse generator, i m , m = 1, 2, ..., n and i f are the m-th phase armature current and excitation current of the multi-phase air-core pulse generator, R m , m = 1, 2, ..., n and R f are the m-th phase armature resistance and excitation resistance of the multi-phase air-core pulse generator respectively, and θ represents the angle at which the axis of the rotor excitation winding of the multi-phase air-core pulse generator rotates to the first phase armature winding of the stator.

[0013] In some preferred embodiments, the non-homogeneous linear integral equation is expressed as:

[0014]

[0015] Among them, k1, k2, k3, …, k n and k f They are c.

[0016] In some preferred embodiments, the non-homogeneous linear integral equation is solved iteratively by Gaussian elimination method, which is:

[0017] When the number of iterations n=1, time t=0, the integral part on the left side of the non-homogeneous linear integral equation is 0, and the first non-homogeneous linear integral equation is obtained;

[0018] Solving the first non-homogeneous linear integral equation by Gaussian elimination method to obtain a coefficient matrix A, and converting the coefficient matrix A into an upper right triangular matrix A′ by triangular transformation;

[0019] Based on the upper right triangular matrix A′, the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration are obtained;

[0020] Substituting the excitation current waveform and each armature current waveform into the left-hand side terms of the non-homogeneous linear integral equation to obtain a second non-homogeneous linear integral equation;

[0021] Assuming the number of iterations n=n+1, the Gaussian elimination method is used to iterate and solve N times to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0022] In some preferred embodiments, when the phase number of the multi-phase air-core pulse generator is four, the coefficient matrix A is expressed as:

[0023]

[0024] Among them, b represents the column vector composed of the terms on the left side of the non-homogeneous linear integral equation, c1, c2, c3, c4 and c f They represent the left side of the equal sign of the non-homogeneous linear integral equation.

[0025] In some preferred embodiments, when the phase number of the multiphase air-core pulse generator is four phases, the coefficient matrix A is converted into an upper right triangular matrix A′ by triangular transformation, and the method is:

[0026] According to the structural characteristics of the four-phase core pulse generator, the mutual inductance of the adjacent phase armature windings of the four-phase core pulse generator is 0, and the coefficient matrix A is set to 12 =M 21 =M 23 =M 32 =M 34 =M 43 =M 41 =M 14 =0 The mutual inductance of the armature windings of the four-phase air-core pulse generator with one phase apart is denoted as M 13 =M 31 =M 24 =M 42 =a, obtain the first coefficient matrix;

[0027] Perform a triangular transformation on the first coefficient matrix to obtain an upper right triangular matrix ′:

[0028]

[0029] Wherein, b′ represents the column vector consisting of the terms on the left side of the equal sign of the non-homogeneous linear integral equation after trigonometric transformation.

[0030] In some preferred embodiments, the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration are expressed as:

[0031]

[0032] Among them, b′5 represents the fifth item of column vector b′, a′ 55 represents the item in the 5th row and 5th column of the coefficient matrix A′, b′m represents the mth term of column vector b′, a′ mj represents the item in the mth row and jth column of the coefficient matrix A′, a′ mm represents the item in the mth row and mth column of the coefficient matrix A′, i j represents the j-th phase armature current, m=1,2,…,n, where n is the number of armatures corresponding to the number of phases of the multi-phase air-core pulse generator.

[0033] In some preferred embodiments, the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator are expressed as follows:

[0034]

[0035] in, The column vector b representing the Nth iteration N Item 5 of Represents the coefficient matrix A of the Nth iteration N The item at row 5 and column 5, The column vector b representing the Nth iteration N The mth term of Represents the coefficient matrix A of the Nth iteration N The item at row m and column j, Represents the coefficient matrix A of the Nth iteration N The item at row m and column m, represents the j-th phase armature current of the N-th iteration.

[0036] Another aspect of the present invention provides a multi-phase air-core pulse generator transient current waveform calculation system, the system comprising the following modules:

[0037] A voltage matrix equation building module is configured to establish voltage matrix equations of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in a natural coordinate system;

[0038] An integration module, configured to integrate the left and right sides of the voltage matrix equation with respect to time t to obtain a corresponding non-homogeneous linear integral equation;

[0039] The equation solving module is configured to solve the non-homogeneous linear integral equation iteratively by Gaussian elimination method to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0040] In some preferred embodiments, the equation solving module includes the following submodules:

[0041] A first equation conversion submodule is configured such that when the number of iterations n=1 and the time t=0, the integral part on the left side of the non-homogeneous linear integral equation is 0, thereby obtaining a first non-homogeneous linear integral equation;

[0042] a Gaussian elimination solving submodule, configured to solve the first non-homogeneous linear integral equation by Gaussian elimination method to obtain a coefficient matrix A, and transform the coefficient matrix A into an upper right triangular matrix A′ by triangular transformation;

[0043] A matrix conversion submodule, configured to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration based on the upper right triangular matrix A′;

[0044] A parameter updating submodule is configured to substitute the excitation current waveform and each armature current waveform into the left-hand terms of the non-homogeneous linear integral equation to obtain a second non-homogeneous linear integral equation;

[0045] The iterative submodule is configured to set the number of iterations n=n+1, and iterates and solves N times through the Gaussian elimination solution submodule, the matrix conversion submodule and the parameter update submodule to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0046] Beneficial effects of the present invention:

[0047] The method for calculating the transient current waveform of a multi-phase air-core pulse generator of the present invention establishes voltage matrix equations for the armature circuit and the excitation circuit of the multi-phase pulse generator. In view of the problem that the mutual inductance between the excitation winding and the armature winding changes periodically with the change of the rotor position, resulting in the inability to directly solve the expressions of the excitation current and each armature current in the differential equation group, the present invention converts the complex differential equation into a linear integral equation group and provides an iterative approximate solution idea for the linear integral equation. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0049] Figure 1 It is a schematic flow chart of a method for calculating transient current waveform of a multi-phase air-core pulse generator of the present invention;

[0050] Figure 2 It is a cross-sectional schematic diagram of a compensation pulse generator according to an embodiment of a method for calculating transient current waveform of a multi-phase air-core pulse generator of the present invention. DETAILED DESCRIPTION

[0051] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0052] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0053] The present invention provides a method for calculating the transient current waveform of a multi-phase air-core pulse generator. The method calculates the transient current waveform of the multi-phase air-core pulse generator based on an integral iteration method. The transient current mentioned here is the transient current of the multi-phase air-core pulse generator during short-circuit discharge. The approximate calculation method effectively reduces the amount of calculation and can provide theoretical guidance for the selection of the discharge trigger angle and the shaping of the discharge current.

[0054] A method for calculating a transient current waveform of a multiphase air-core pulse generator of the present invention comprises:

[0055] Establishing voltage matrix equations of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in a natural coordinate system;

[0056] Integrate the left and right sides of the voltage matrix equation with respect to time t to obtain a corresponding non-homogeneous linear integral equation;

[0057] The non-homogeneous linear integral equation is solved iteratively by Gaussian elimination method to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0058] In order to more clearly illustrate the method for calculating the transient current waveform of the multi-phase air-core pulse generator of the present invention, the following is combined with Figure 1 Each step in the embodiment of the present invention is described in detail.

[0059] The method for calculating the transient current waveform of a multi-phase air-core pulse generator of the first embodiment of the present invention is described in detail with the number of motor phases being 4, and includes steps S10 to S30, each of which is described in detail as follows:

[0060] Step S10, establishing the voltage matrix equation of the armature circuit and the excitation circuit of the four-phase air-core pulse generator in the natural coordinate system, as shown in formula (1):

[0061]

[0062] Among them, M rs , r=1,2,…,n,s=1,2,…,n represents the mutual inductance between the rth phase armature winding and the Sth phase armature winding of the multi-phase air-core pulse generator, L represents the self-inductance of the armature winding of the multi-phase air-core pulse generator, L f represents the self-inductance of the excitation winding of the multi-phase air-core pulse generator, M represents the maximum mutual inductance of the excitation winding and armature winding of the multi-phase air-core pulse generator, i m , m = 1, 2, ..., n and i fare the m-th phase armature current and excitation current of the multi-phase air-core pulse generator, R m , m = 1, 2, ..., n and R f They are respectively the m-th phase armature resistance and excitation resistance of the multi-phase air-core pulse generator. θ represents the angle from the axis of the rotor excitation winding of the multi-phase air-core pulse generator to the first phase armature winding of the stator, which can be used to judge the ignition angle.

[0063] like Figure 2 As shown, it is a cross-sectional schematic diagram of a compensation pulse generator of an embodiment of a method for calculating transient current waveform of a multi-phase air-core pulse generator of the present invention, wherein 1 is an excitation winding, 2 is an air gap, and 3 is an armature winding.

[0064] Step S20, integrating the left and right sides of the voltage matrix equation with respect to time t to obtain a corresponding non-homogeneous linear integral equation, as shown in equation (2):

[0065]

[0066] Among them, k1, k2, k3, …, k n and k f are the constant terms generated by the integral.

[0067] Step S30, solving the non-homogeneous linear integral equation by iterative Gaussian elimination method to obtain the excitation current waveform and each armature current waveform of the four-phase air-core pulse generator.

[0068] Step S31, when the number of iterations n=1, time t=0, the integral part on the left side of the non-homogeneous linear integral equation is 0, and the first non-homogeneous linear integral equation is obtained, as shown in formula (3):

[0069]

[0070] Among them, c1, c2, c3, c4 and c f They represent the left side of the equal sign of the non-homogeneous linear integral equation.

[0071] Step S32, solving the first non-homogeneous linear integral equation by Gaussian elimination method to obtain a coefficient matrix A, and converting the coefficient matrix A into an upper right triangular matrix A′ by triangular transformation.

[0072] The coefficient matrix A is expressed as shown in formula (4):

[0073]

[0074] Among them, b represents the column vector composed of the terms on the left side of the non-homogeneous linear integral equation, c1, c2, c3, c4 and c fThey represent the left side of the equal sign of the non-homogeneous linear integral equation.

[0075] According to the structural characteristics of the four-phase core pulse generator, the mutual inductance of the adjacent phase armature windings of the four-phase core pulse generator is 0, and the coefficient matrix A is set to 12 =M 21 =M 23 =M 32 =M 34 =M 43 =M 41 =M 14 = 0, and the mutual inductance of the armature windings of the four-phase air-core pulse generator with one phase apart is recorded as M 13 =M 31 =M 24 =M 42 =a, and obtain the first coefficient matrix.

[0076] Perform triangular transformation on the first coefficient matrix to obtain an upper right triangular matrix A′, as shown in formula (5):

[0077]

[0078] Wherein, b′ represents the column vector consisting of the terms on the left side of the equal sign of the non-homogeneous linear integral equation after trigonometric transformation.

[0079] When the number of phases of the multi-phase air-core pulse generator is n, the Gaussian elimination iterative operation is performed with reference to the process of formula (1) to formula (5) above to obtain the system matrix and the upper right triangular matrix corresponding to the n-phase air-core pulse generator, which are used for the subsequent calculation of the excitation current waveform and each armature current waveform. The present invention will not be described in detail here.

[0080] Step S33, based on the upper right triangular matrix A′, the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration are obtained, as shown in formula (6):

[0081]

[0082] Among them, b′5 represents the fifth item of column vector b′, a′ 55 represents the item in the 5th row and 5th column of the coefficient matrix A′, b′ m represents the mth term of column vector b′, a′ mj represents the item in the mth row and jth column of the coefficient matrix A′, a′ mm represents the item in the mth row and mth column of the coefficient matrix A′, i j represents the j-th phase armature current, m=1,2,…,n, where n is the number of armatures corresponding to the number of phases of the multi-phase air-core pulse generator.

[0083] Step S34, substituting the excitation current waveform and each armature current waveform into the left-hand side terms of the non-homogeneous linear integral equation to obtain a second non-homogeneous linear integral equation.

[0084] Step S35, let the number of iterations n=n+1, and iterate and solve N times by the Gaussian elimination method of steps S32 to S34 to obtain the excitation current waveform and each armature current waveform of the four-phase air-core pulse generator, as shown in formula (7):

[0085]

[0086] in, The column vector b representing the Nth iteration N Item 5 of Represents the coefficient matrix A of the Nth iteration N The item at row 5 and column 5, Column vector b representing the Nth iteration N The mth term of Represents the coefficient matrix A of the Nth iteration N The item at row m and column j, Represents the coefficient matrix A of the Nth iteration N The item at row m and column m, represents the j-th phase armature current of the N-th iteration.

[0087] In the first iteration, time t = 0, the left side of formula (2) is c1, c2, c3, c4 and c f The initial value of is solved to the excitation current waveform and each armature current waveform of the first iteration of the multi-phase air-core pulse generator shown in equation (6), and then it is substituted into equation (2). The second iteration is solved by the method of steps S32 to S34, and the solution result is substituted into equation (2) again. By analogy, N times (N tends to infinity) iteration is performed to obtain the final expression of the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0088] The above-mentioned transient current waveform calculation process of the multi-phase core pulse generator is an approximate solution process. It is aimed at the pulse generator. Since the mutual inductance between the excitation winding and the electromagnetic winding is related to the rotor position, it is a trigonometric function of 1 times the rotation angle. Therefore, the equation group is a variable coefficient equation, which is a very difficult problem to solve directly. The approximate solution is used instead of the direct solution to realize the transient current waveform calculation of the multi-phase air-core pulse generator.

[0089] Although the various steps in the above embodiment are described in the above-mentioned order, those skilled in the art can understand that in order to achieve the effect of this embodiment, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple changes are within the scope of protection of the present invention.

[0090] The multi-phase air-core pulse generator transient current waveform calculation system of the second embodiment of the present invention comprises the following modules:

[0091] A voltage matrix equation building module is configured to establish voltage matrix equations of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in a natural coordinate system;

[0092] An integration module, configured to integrate the left and right sides of the voltage matrix equation with respect to time t to obtain a corresponding non-homogeneous linear integral equation;

[0093] The equation solving module is configured to solve the non-homogeneous linear integral equation iteratively by Gaussian elimination method to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0094] Among them, the program solving module includes the following sub-modules:

[0095] A first equation conversion submodule is configured such that when the number of iterations n=1 and the time t=0, the integral part on the left side of the non-homogeneous linear integral equation is 0, thereby obtaining a first non-homogeneous linear integral equation;

[0096] a Gaussian elimination solving submodule, configured to solve the first non-homogeneous linear integral equation by Gaussian elimination method to obtain a coefficient matrix A, and transform the coefficient matrix A into an upper right triangular matrix A′ by triangular transformation;

[0097] A matrix conversion submodule, configured to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration based on the upper right triangular matrix A′;

[0098] A parameter updating submodule is configured to substitute the excitation current waveform and each armature current waveform into the left-hand terms of the non-homogeneous linear integral equation to obtain a second non-homogeneous linear integral equation;

[0099] The iterative submodule is configured to set the number of iterations n=n+1, and iterates and solves N times through the Gaussian elimination solution submodule, the matrix conversion submodule and the parameter update submodule to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

[0100] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0101] It should be noted that the transient current waveform calculation system of the multi-phase air-core pulse generator provided in the above embodiment is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps, and are not regarded as improper limitations of the present invention.

[0102] An electronic device according to a third embodiment of the present invention includes:

[0103] at least one processor; and

[0104] a memory communicatively connected to at least one of the processors; wherein,

[0105] The memory stores instructions that can be executed by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned method for calculating the transient current waveform of the multi-phase air-core pulse generator.

[0106] A fourth embodiment of the present invention is a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above-mentioned method for calculating the transient current waveform of the multi-phase air-core pulse generator.

[0107] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the storage device and processing device described above can refer to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0108] Those skilled in the art should be able to appreciate that the modules and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, computer software or a combination of the two, and the programs corresponding to the software modules and method steps can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the technical field. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0109] The terms "first", "second", etc. are used to distinguish similar objects rather than to describe or indicate a particular order or sequence.

[0110] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0111] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for calculating transient current waveform of a multiphase air-core pulse generator, characterized in that: The method includes: The voltage matrix equations of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in the natural coordinate system are established: Among them, M rs , r=1,2,…,n,s=1,2,…,n represents the mutual inductance between the rth phase armature winding and the Sth phase armature winding of the multi-phase air-core pulse generator, L represents the self-inductance of the armature winding of the multi-phase air-core pulse generator, L f represents the self-inductance of the excitation winding of the multi-phase air-core pulse generator, M represents the maximum mutual inductance of the excitation winding and armature winding of the multi-phase air-core pulse generator, i m , m = 1, 2, ..., n and i f are the m-phase armature current and excitation current of the multi-phase air-core pulse generator, R m ,m=1,2,…,n and R f are the m-th phase armature resistance and excitation resistance of the multi-phase air-core pulse generator, respectively; θ represents the angle at which the axis of the rotor excitation winding of the multi-phase air-core pulse generator rotates to the first phase armature winding of the stator; Integrate the left and right sides of the voltage matrix equation with respect to time t to obtain a corresponding non-homogeneous linear integral equation; The non-homogeneous linear integral equation is solved iteratively by Gaussian elimination method to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

2. The method for calculating transient current waveform of a multiphase air-core pulse generator according to claim 1, characterized in that: The non-homogeneous linear integral equation is expressed as: Among them, k1, k2, k3, …, k n and k f are the constant terms generated by the integral.

3. The method for calculating transient current waveform of a multiphase air-core pulse generator according to claim 2, characterized in that: The non-homogeneous linear integral equation is solved iteratively by Gaussian elimination method, and the method is: When the number of iterations n=1, time t=0, the integral part on the left side of the non-homogeneous linear integral equation is 0, and the first non-homogeneous linear integral equation is obtained; Solving the first non-homogeneous linear integral equation by Gaussian elimination method to obtain a coefficient matrix A, and converting the coefficient matrix A into an upper right triangular matrix A′ by triangular transformation; Based on the upper right triangular matrix A′, the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration are obtained; Substituting the excitation current waveform and each armature current waveform into the left-hand side terms of the non-homogeneous linear integral equation to obtain a second non-homogeneous linear integral equation; Assuming the number of iterations n=n+1, the Gaussian elimination method is used to iterate and solve N times to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

4. The method for calculating transient current waveform of a multiphase air-core pulse generator according to claim 3, characterized in that: When the phase number of the multiphase air-core pulse generator is four, the coefficient matrix A is expressed as: Among them, b represents the column vector composed of the terms on the left side of the non-homogeneous linear integral equation, c1, c2, c3, c4 and c f They represent the left side of the equal sign of the non-homogeneous linear integral equation.

5. The method for calculating transient current waveform of a multiphase air-core pulse generator according to claim 4, characterized in that: When the phase number of the multiphase air-core pulse generator is four, the coefficient matrix A is converted into an upper right triangular matrix A′ by triangular transformation, and the method is as follows: According to the structural characteristics of the four-phase core pulse generator, the mutual inductance of the adjacent phase armature windings of the four-phase core pulse generator is 0, and the coefficient matrix A is set to 12 =M 21 =M 23 =M 32 =M 34 =M 43 =M 41 =M 14 = 0, and the mutual inductance of the armature windings of the four-phase air-core pulse generator with one phase apart is recorded as M 13 =M 31 =M 24 =M 42 =s, obtain the first coefficient matrix; Perform a triangular transformation on the first coefficient matrix to obtain an upper right triangular matrix A′: Wherein, b′ represents the column vector consisting of the terms on the left side of the equal sign of the non-homogeneous linear integral equation after trigonometric transformation.

6. The method for calculating transient current waveform of a multiphase air-core pulse generator according to claim 5, characterized in that: The excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration are expressed as follows: Among them, b′5 represents the fifth item of column vector b′, a′ 55 represents the item in the 5th row and 5th column of the coefficient matrix A′, b′ m represents the mth term of column vector b′, a′ mj represents the item in the mth row and jth column of the coefficient matrix A′, a′ mm represents the item in the mth row and mth column of the coefficient matrix A′, i j represents the j-th phase armature current, m=1,2,…,n, where n is the number of armatures corresponding to the number of phases of the multi-phase air-core pulse generator.

7. The method for calculating transient current waveform of a multi-phase air-core pulse generator according to claim 6, characterized in that: The excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator are expressed as follows: in, The column vector b representing the Nth iteration N Item 5 of Represents the coefficient matrix A of the Nth iteration N The item at row 5 and column 5, Column vector b representing the Nth iteration N The mth term of Represents the coefficient matrix A of the Nth iteration N The item at row m and column j, Represents the coefficient matrix A of the Nth iteration N The item at row m and column m, represents the j-th phase armature current of the N-th iteration.

8. A transient current waveform calculation system for a multiphase air-core pulse generator, characterized in that: The system includes the following modules: The voltage matrix equation building module is configured to establish the voltage matrix equations of the armature circuit and the excitation circuit of the multi-phase air-core pulse generator in the natural coordinate system: Among them, M rs ,r=1,2,…,n,s=1,2,…,n represents the mutual inductance between the rth phase armature winding and the Sth phase armature winding of the multi-phase air-core pulse generator, L represents the self-inductance of the armature winding of the multi-phase air-core pulse generator, L f represents the self-inductance of the excitation winding of the multi-phase air-core pulse generator, M represents the maximum mutual inductance of the excitation winding and armature winding of the multi-phase air-core pulse generator, i m ,m=1,2,…,n and i f are the m-phase armature current and excitation current of the multi-phase air-core pulse generator, R m ,m=1,2,…,n and R f are the m-th phase armature resistance and excitation resistance of the multi-phase air-core pulse generator, respectively; θ represents the angle at which the axis of the rotor excitation winding of the multi-phase air-core pulse generator rotates to the first phase armature winding of the stator; An integration module, configured to integrate the left and right sides of the voltage matrix equation with respect to time t to obtain a corresponding non-homogeneous linear integral equation; The equation solving module is configured to solve the non-homogeneous linear integral equation iteratively by Gaussian elimination method to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

9. The transient current waveform calculation system of a multi-phase air-core pulse generator according to claim 8, characterized in that: The equation solving module includes the following submodules: A first equation conversion submodule is configured such that when the number of iterations n=1 and the time t=0, the integral part on the left side of the non-homogeneous linear integral equation is 0, thereby obtaining a first non-homogeneous linear integral equation; a Gaussian elimination solving submodule, configured to solve the first non-homogeneous linear integral equation by Gaussian elimination method to obtain a coefficient matrix A, and transform the coefficient matrix A into an upper right triangular matrix A′ by triangular transformation; A matrix conversion submodule, configured to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator of the first iteration based on the upper right triangular matrix A′; A parameter updating submodule is configured to substitute the excitation current waveform and each armature current waveform into the left-hand terms of the non-homogeneous linear integral equation to obtain a second non-homogeneous linear integral equation; The iterative submodule is configured to set the number of iterations n=n+1, and iterates and solves N times through the Gaussian elimination solution submodule, the matrix conversion submodule and the parameter update submodule to obtain the excitation current waveform and each armature current waveform of the multi-phase air-core pulse generator.

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