High-frequency transformer high-frequency oscillation analysis method and system considering line stray parameters under square wave excitation

Abstract

The invention discloses a high-frequency transformer high-frequency oscillation analysis method and system considering stray parameters of a power supply line under high-frequency square wave excitation. According to the method, an open-circuit and short-circuit test means is adopted to obtain impedance parameters of the high-frequency transformer, and distribution parameters such as power supply line resistance, parasitic inductance and parasitic capacitance of the high-frequency transformer are obtained through impedance characteristic test. On this basis, a distribution parameter model of the high-frequency transformer is constructed, and order reduction splitting is performed on the distribution parameter model on the premise of neglecting capacitance between windings, so that a low-order sub-circuit model easy to analyze is formed. And the equivalent distribution parameter sub-circuit model obtained through reduced-order splitting is utilized to analyze and calculate the response of the transformer port voltage and the winding current under high-frequency square wave excitation, and detailed analysis of the waveform of the high-frequency transformer and research of the high-frequency oscillation characteristic are realized. The method can quantify the specific influence of the parameters of the high-frequency transformer on the oscillation characteristics, provides guidance for the suppression and elimination of high-frequency oscillation, and guarantees the efficient and stable operation of the high-frequency transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of high-frequency transformers, and particularly to a high-frequency oscillation analysis method and system for a high-frequency transformer considering stray parameters of a power supply line under square-wave excitation. Background Art

[0002] With the transformation of the global energy structure and the rapid development of power electronics technology, power electronic transformers, as key equipment for the grid connection of distributed power systems, have received increasing attention in terms of research and application. Power electronic transformers integrate information technology and power electronic conversion technology, and have the ability of bidirectional energy transmission and efficient utilization, especially suitable for large-scale power transmission requirements. Among them, high-frequency transformers, as the core components of power electronic transformers, have become the key to achieving high performance and reliability of power electronic transformers due to their advantages such as small volume, large capacity, strong controllability, high power density, and AC-DC mixing.

[0003] Due to the fast switching characteristics of power electronic devices, the excitation voltage at the ports of high-frequency transformers is often a non-sinusoidal excitation after power electronic conversion, such as square waves, stepped waves, etc. The high voltage rise rate generated by this switching action will cause significant high-frequency oscillation phenomena between the distributed capacitance and inductive elements of the transformer. This high-frequency oscillation not only increases the voltage stress at the ports of high-frequency transformers, but also raises the requirements for the insulation performance of epoxy resin, resulting in additional high-frequency losses, and may also have an adverse impact on the electromagnetic environment of the system, causing electromagnetic interference and common-mode noise, thus affecting the reliability of power electronic transformers. The traditional analysis methods based on power-frequency steady state are no longer applicable to high-frequency transformers because they do not consider the electromagnetic transient characteristics at high frequencies. Therefore, it is particularly crucial to conduct in-depth analysis of the high-frequency oscillations of voltage and current that may occur in high-frequency transformers under electromagnetic transient phenomena. In existing research, the research on the electromagnetic transient characteristics of high-frequency transformers mainly focuses on aspects such as the extraction of electromagnetic parameters under high-frequency non-sinusoidal excitation, the establishment of high-frequency equivalent models, and the analysis of high-frequency transmission characteristics. There is less research on the high-frequency oscillation characteristics that may occur in the port voltage and winding current responses of high-frequency transformers, especially the analytical analysis of the high-frequency oscillations caused by electromagnetic transient characteristics in high-frequency transformers under high-frequency square-wave excitation from the circuit level. At the same time, overly complex finite element simulation models lead to too long simulation time and low efficiency. The analysis based on the equivalent circuit model is of great significance for improving the high-frequency oscillation analysis efficiency of the prototype of high-frequency transformers in the preliminary design stage. Summary of the Invention

[0004] The object of the present invention is to provide a high-frequency oscillation analysis method and system for a high-frequency transformer considering the stray parameters of the power supply line under high-frequency square-wave excitation, aiming to achieve an in-depth analysis of the high-frequency oscillation characteristics of the high-frequency transformer by splitting the circuit parameter network of the equivalent distributed parameter model. This method first obtains the impedance parameters of the high-frequency transformer, and then obtains the distributed parameters such as the resistance of the power supply line, parasitic inductance, and parasitic capacitance of the high-frequency transformer. On this basis, a distributed parameter model of the high-frequency transformer is constructed, and it is reduced and split on the premise of ignoring the capacitance between windings to form a low-order sub-circuit model that is easy to analyze. Using the equivalent distributed parameter sub-circuit model obtained by the reduction and splitting, the responses of the port voltage and winding current of the transformer under high-frequency square-wave excitation are analyzed and calculated, and further the detailed analysis of the waveform of the high-frequency transformer and the study of the high-frequency oscillation characteristics are realized. The present invention can quantify the specific influence of the high-frequency transformer parameters on the oscillation characteristics, provide guidance for the suppression and elimination of high-frequency oscillations, and ensure the efficient and stable operation of the high-frequency transformer.

[0005] To achieve the above object, the technical solution provided by the present invention is as follows: In the first aspect, a high-frequency oscillation analysis method for a high-frequency transformer considering line stray parameters under square-wave excitation includes the following steps: By means such as open-circuit and short-circuit tests, obtain impedance parameters such as the magnetizing impedance and leakage impedance of the high-frequency transformer, and by means such as impedance characteristic tests using an impedance analyzer, obtain distributed parameters such as the distributed capacitance of the high-frequency transformer, the resistance of the power supply line, and parasitic inductance; According to the impedance parameters and distributed parameters, establish an equivalent distributed parameter circuit model of the high-frequency transformer considering the stray parameters of the power supply line; Reduce and split the equivalent distributed parameter circuit model to obtain a primary-side capacitance loop sub-circuit model, a secondary-side capacitance loop sub-circuit model, and a parallel magnetizing branch loop sub-circuit model; Obtain the capacitance voltage expression and current expression of the primary-side capacitance loop and the secondary-side capacitance loop through analytical calculation; Reduce and split the parallel magnetizing branch into a magnetizing inductance loop and a magnetizing resistance loop, and obtain the current expressions of the magnetizing inductance loop and the magnetizing resistance loop; Input the high-frequency square-wave voltage as an excitation into the reduced model, and obtain the port voltage and no-load current waveforms considering the parasitic parameters of the high-frequency transformer according to the reduced model expression, and analyze the high-frequency oscillation mechanism of the high-frequency transformer.

[0006] Furthermore, when establishing the equivalent distributed parameter circuit model of the high-frequency transformer considering the stray parameters of the power supply line, ignore the distributed capacitance between the primary and secondary windings.

[0007] Further, the equivalent distributed parameter circuit model of the high-frequency transformer includes the resistance and parasitic inductance of the power supply line, and considers the influence of the stray parameters of the power supply line on the waveforms of the port voltage and winding current of the high-frequency transformer.

[0008] Further, the reduced-order split primary-side capacitor sub-circuit is in the form of a series branch, and the capacitor element is the inter-turn capacitance of the primary winding; the secondary-side capacitor sub-circuit is in the form of a series branch, and the capacitor element is the inter-turn capacitance of the secondary winding; the exciting branch circuit is in the form of a parallel branch.

[0009] Further, the capacitance voltage expressions of the primary-side capacitor circuit and the secondary-side capacitor circuit are: ; ; ; Among them, u C (t) represents the capacitance voltage, u 1 (t) represents the forced component of the capacitance voltage related to the applied excitation, u 2 (t) represents the free component of the capacitance voltage related to the initial state of the capacitor, U 0 represents the amplitude of the square-wave voltage, r 、 l and C s respectively represent the total resistance, total inductance and total capacitance in the circuit; for the sub-circuit including the primary-side capacitor, r represents the resistance of the power supply line, l represents the stray inductance of the power supply line, C s represents the distributed capacitance of the primary winding; for the sub-circuit including the secondary-side capacitor, r represents the sum of the resistance of the power supply line and the resistance of the transformer winding, l represents the stray inductance of the power supply line l and the sum of the leakage inductance of the winding, C s represents the distributed capacitance of the secondary winding.

[0010] Further, the current expressions of the primary-side capacitor circuit and the secondary-side capacitor circuit are: ; ; Among them, i C (t) is the current on the capacitance branch, i1 (t) represents the forced component of the capacitive current related to the applied excitation, i 2 (t) represents the free component of the capacitive current related to the initial state of the capacitor.

[0011] Furthermore, the current expressions for the exciting inductance loop and the exciting resistance loop are as follows: ; wherein, i 1 (t) represents the current of the exciting inductance loop, i 2 (t) represents the current of the exciting resistance loop, L m , L σ are the exciting inductance and the leakage inductance of the winding respectively, R m , R w are the exciting resistance and the winding resistance respectively.

[0012] In a second aspect, a high-frequency transformer high-frequency oscillation analysis system for considering the stray parameters of the power supply line under high-frequency square-wave excitation is provided, including: a parameter acquisition module, a distributed parameter model establishment module, a high-frequency oscillation analysis module, and a waveform analysis module; The parameter acquisition module is used to acquire the impedance parameters of the high-frequency transformer and the distributed parameters of the high-frequency transformer; The distributed parameter model establishment module is used to establish a three-capacitor equivalent distributed parameter model of the high-frequency transformer considering the stray parameters of the power supply line according to the impedance parameters and the distributed parameters, reduce the order and split the circuit model on the premise of ignoring the capacitance between the primary and secondary windings, and split the three-capacitor equivalent distributed parameter model of the high-frequency transformer considering the stray parameters of the power supply line into a primary-side capacitance loop, a secondary-side capacitance loop, and a parallel exciting branch loop; meanwhile, the parallel exciting branch loop is further split into an exciting inductance loop and an exciting resistance loop; The high-frequency oscillation analysis module is used to substitute the impedance parameters and the distributed parameters of the high-frequency transformer including the power supply line extracted, and calculate the oscillation frequency and the oscillation attenuation speed of the port voltage and the winding current of the high-frequency transformer under high-frequency square-wave excitation; The waveform analysis module is used to substitute the impedance parameters and the distributed parameters of the high-frequency transformer including the power supply line extracted, and calculate the waveforms of the port voltage and the winding current of the high-frequency transformer under high-frequency square-wave excitation of the split low-order sub-circuit loops.

[0013] Furthermore, the oscillation frequency and the oscillation attenuation speed of the port voltage and the winding current of the high-frequency transformer under high-frequency square-wave excitation are specifically: ; Among them, r , l and C s respectively represent the total resistance, total inductance, and total capacitance in the sub - circuit loop; for the sub - circuit loop containing the primary - side capacitor, r represents the resistance of the power supply line, l represents the stray inductance of the power supply line, C s represents the distributed capacitance of the primary - side winding; for the sub - circuit loop containing the secondary - side capacitor, r represents the sum of the resistance of the power supply line and the resistance of the transformer winding, l represents the sum of the stray inductance of the power supply line and the leakage inductance of the transformer winding, C s represents the distributed capacitance of the secondary - side winding; The high - frequency oscillation analysis module obtains the high - frequency oscillation frequency and oscillation attenuation rate of the primary - side port voltage of the high - frequency transformer under the high - frequency square - wave excitation by substituting the circuit parameters of the primary - side capacitor loop; and obtains the high - frequency oscillation frequency and oscillation attenuation rate of the secondary - side port voltage by substituting the circuit parameters of the secondary - side capacitor loop.

[0014] Furthermore, for the primary - side capacitor sub - loop and the secondary - side capacitor sub - loop, the analytical expressions of the capacitor voltage and the loop current of the waveform analysis module are specifically: ; ; Among them, u 1 (t), i 1 (t) represent the current forced components related to the applied excitation, u 2 (t), i 2 (t) represent the free components of the capacitor voltage and current related to the initial state of the capacitor; r , l and C s respectively represent the total resistance, total inductance, and total capacitance in the sub - circuit loop; for the sub - circuit loop containing the primary - side capacitor, r represents the resistance of the power supply line, l represents the stray inductance of the power supply line, C s represents the distributed capacitance of the primary - side winding; for the sub - circuit loop containing the secondary - side capacitor, r represents the sum of the resistance of the power supply line and the resistance of the transformer winding, l represents the sum of the stray inductance of the power supply line and the leakage inductance of the winding,C s represents the distributed capacitance of the secondary winding; U 0 represents the amplitude of the square-wave voltage, and the expressions for α, β, and θ are specifically: ; For the parallel excitation branch circuit, after further splitting it into an excitation inductance circuit and an excitation resistance circuit, the analytical expression of the loop current is specifically: ; Among them, i 1 iL(t) represents the current of the excitation inductance circuit, i 2 iR(t) represents the current of the excitation resistance circuit, L m , L σ Lm and Lσ are the excitation inductance and the leakage inductance of the winding respectively, R m , R w Rm and Rσ are the excitation resistance and the winding resistance respectively.

[0015] The present invention has the following beneficial technical effects: (1) The high-frequency oscillation analysis method of the high-frequency transformer obtained by splitting the circuit parameter network according to the present invention does not need to consider the transformer type and is applicable to the high-frequency oscillation analysis of different types of high-frequency transformers, and has practicability and universality in engineering applications.

[0016] (2) The present invention can realize the waveform analysis of the high-frequency transformer under high-frequency square-wave excitation and the research on the high-frequency oscillation mechanism, can quantify the influence of the relevant parameters of the high-frequency transformer on the high-frequency oscillation, provide guidance for the suppression and elimination of the high-frequency oscillation, and ensure the efficient and stable operation of the high-frequency transformer. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the high-frequency oscillation analysis process of a high-frequency transformer considering the stray parameters of the power supply line under high-frequency square-wave excitation; Figure 2 is the high-frequency oscillation phenomenon of the port voltage and no-load current of the high-frequency transformer prototype under high-frequency square-wave excitation; Figure 3 is a schematic diagram of the equivalent distributed parameter circuit model of the high-frequency transformer considering the stray parameters of the power supply line; Figure 4 is a schematic diagram of the primary capacitance circuit obtained by reducing the order and splitting the equivalent circuit; Figure 5 is a schematic diagram of the secondary capacitance circuit obtained by reducing the order and splitting the equivalent circuit; Figure 6 Schematic diagram of the shunt excitation branch circuit obtained by reducing the order and splitting of the equivalent circuit Figure 7 Schematic diagram of the excitation inductance circuit obtained by reducing the order and splitting of the shunt excitation branch circuit Figure 8 Schematic diagram of the excitation resistance circuit obtained by reducing the order and splitting of the shunt excitation branch circuit Figure 9 Block diagram of the high - frequency oscillation analysis system of the high - frequency transformer Specific implementation mode

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings of the specification and the specific implementation mode.

[0019] The idea of the present invention is as follows: First, obtain the impedance parameters and distributed capacitance parameters of the high - frequency transformer, obtain the stray parameters of the power supply line, establish an equivalent distributed parameter model of the high - frequency transformer according to the impedance parameters and distributed parameters. On the premise of ignoring the capacitance between windings, reduce the order and split the equivalent distributed parameter model into three sub - circuit models. Input the high - frequency square - wave voltage as the excitation into the reduced - order sub - model, analyze and calculate the response of the port voltage and winding current of the high - frequency transformer, reveal the inherent dynamic characteristics of the impedance resonance network of the high - frequency transformer, realize the analysis of the waveform of the high - frequency transformer and the research of the high - frequency oscillation mechanism, be able to quantify the specific influence of the high - frequency transformer parameters on the high - frequency oscillation characteristics, provide guidance for the suppression and elimination of high - frequency oscillation, and be beneficial to the efficient and stable operation of the high - frequency transformer.

[0020] As Figure 1 shown, the embodiment of the present invention provides a specific embodiment of the high - frequency oscillation analysis of a high - frequency transformer considering the stray parameters of the power supply line under high - frequency square - wave excitation. Analyze a 20kVA copper - foil winding high - frequency transformer prototype. The high - frequency oscillation phenomena of the port voltage and no - load current of the prototype are as Figure 2 shown, and specifically include the following steps: Step 1: Obtain impedance parameters such as the excitation impedance and leakage impedance of the high - frequency transformer through open - circuit and short - circuit test means; Step 2: Conduct impedance characteristic tests through an impedance analyzer to obtain distributed parameters such as the distributed capacitance of the high - frequency transformer, the resistance of the power supply line, and the parasitic inductance. The obtained impedance parameters and distributed parameters are shown in Table 1; Step 3: According to the measured impedance parameters and distributed parameters of the high - frequency transformer, establish an equivalent distributed parameter circuit model of the high - frequency transformer considering the stray parameters of the power supply line, as Figure 3 shown; Step 4: Reduce the order and split the established equivalent distributed parameter circuit model to obtain three sub - circuit models: the primary - side capacitance circuit, the secondary - side capacitance circuit, and the shunt excitation branch circuit, as Figure 4 andFigure 5 , Figure 6 as shown in; Step 5: Obtain the capacitance voltage expressions of the primary-side capacitance loop and the secondary-side capacitance loop and the current expressions of the capacitance branches through analytical calculation; Step 6: Further reduce the order of the parallel excitation branch and split it into an excitation inductance loop and an excitation resistance loop, as shown in Figure 7 , Figure 8 as shown, and analytically solve the current expressions of the two sub-loops respectively; Step 7: Input the high-frequency square wave voltage as an excitation into the reduced-order sub-model. According to the analytical expressions of the reduced-order sub-model, obtain the port voltage and no-load current waveforms considering the parasitic parameters of the high-frequency transformer, and analyze the high-frequency oscillation mechanism of the high-frequency transformer.

[0021] The equivalent distributed parameter model of the high-frequency transformer considering the stray parameters of the power supply line is as shown in Figure 3 As shown, since there are a large number of dynamic elements in this model, it is relatively complex to solve the exact analytical expressions of its voltage and current responses, and the capacitance value between the primary and secondary windings cannot be well considered in the analytical calculation. Therefore, the distributed capacitance between the primary and secondary windings can be ignored, and the influence of the capacitance between turns of the primary and secondary windings can be mainly considered.

[0022] For the primary-side and secondary-side capacitance sub-circuits, according to Kirchhoff's voltage law, a differential equation about the capacitance voltage u C (t) can be written as shown in Equation (1): ; In the formula, u represents the power supply voltage excitation. r , l and C s respectively represent the total resistance, total inductance, and total capacitance in the loop. For the sub-circuit loop containing the primary-side capacitance, r represents the resistance of the power supply line, l represents the stray inductance of the power supply line, represents the distributed capacitance of the primary winding; for the sub-circuit loop containing the secondary-side capacitance, r represents the sum of the resistance of the power supply line and the winding resistance of the transformer, l represents the stray inductance of the power supply line l and the sum of the leakage inductance of the winding, C s represents the distributed capacitance of the secondary winding.

[0023] Furthermore, using the step function to represent the rising edge of the ideal square wave voltage, performing Laplace transform on the differential equation shown in Equation (1) can solve the capacitance voltage in the complex frequency domain.u c The expression of \(v(t)\) is shown in Equation (2). According to the sub-circuit model obtained by order reduction and splitting, the capacitor voltages of the primary and secondary capacitor circuits are calculated and expressed as Equations (3) and (4): ; ; ; where, u C \(v(t)\) represents the capacitor voltage, u 1 \(v_{f}(t)\) represents the forced component of the capacitor voltage related to the applied excitation, u 2 \(v_{n}(t)\) represents the free component of the capacitor voltage related to the initial state of the capacitor, U 0 \(V\) represents the amplitude of the square-wave voltage, r 、 l and C s \(R\), \(L\) and \(C\) represent the total resistance, total inductance and total capacitance in the circuit respectively. For the sub-circuit loop containing the primary capacitor, r \(R_{1}\) represents the resistance of the power supply line, l \(L_{1}\) represents the stray inductance of the power supply line, C s \(C_{1}\) represents the distributed capacitance of the primary winding; for the sub-circuit loop containing the secondary capacitor, r \(R_{2}\) represents the sum of the resistance of the power supply line and the resistance of the transformer winding, l \(L_{2}\) represents the stray inductance of the power supply line l and the sum of the leakage inductance of the winding, C s \(C_{2}\) represents the distributed capacitance of the secondary winding.

[0024] According to the sub-circuit model obtained by order reduction and splitting, the currents of the primary and secondary capacitor circuits are calculated and expressed as Equations (5) and (6): ; ; where, i C \(i(t)\) is the current on the capacitor branch, i 1 \(i_{f}(t)\) represents the forced component of the capacitor current related to the applied excitation, i 2 \(i_{n}(t)\) represents the free component of the capacitor current related to the initial state of the capacitor.

[0025] According to the sub - circuit of the shunt - excited branch, it is further reduced - order and split into an exciting - inductance sub - loop and an exciting - resistance sub - loop. Since the resistance and parasitic inductance of the power - supply line are much smaller than the leakage impedance of the transformer winding, their influence on the circuit can be completely replaced by the winding leakage impedance. Therefore, the resistance and parasitic inductance of the power - supply line can be ignored. According to Kirchhoff's voltage law, the differential equation about the loop current can be written as shown in Equation (7): ; where, u represents the power - supply voltage excitation. R and L respectively represent the total resistance and total inductance in the loop. For the sub - loop containing only the exciting inductance, L represents the sum of the winding leakage inductance and the exciting inductance, R represents the winding resistance; for the sub - loop containing only the exciting resistance, L represents the winding leakage inductance, R represents the sum of the winding resistance and the exciting resistance.

[0026] Furthermore, using the step function to represent the rising edge of the ideal square - wave voltage, the Laplace transform of the differential equation shown in Equation (7) can be used to solve the expressions of the two sub - loop currents in the complex - frequency domain as shown in Equation (8).

[0027] ; where, i 1 (t) represents the current of the exciting - inductance loop, i 2 (t) represents the current of the exciting - resistance loop, L m , L σ are the exciting inductance and the winding leakage inductance respectively, R m , R w are the exciting resistance and the winding resistance respectively.

[0028] According to the obtained analytical expressions, substituting the parasitic parameters of the power - supply line and the parameters of the high - frequency transformer to analyze the high - frequency oscillation mechanism of the high - frequency transformer under high - frequency square - wave excitation, including the oscillation frequency and the oscillation attenuation speed.

[0029] Based on the same technical concept, another embodiment of the present application also provides a high - frequency oscillation analysis system for a high - frequency transformer, as shown in Figure 9 shown, with each module coupled in sequence. The system includes: The parameter acquisition module is used to extract impedance parameters such as the exciting impedance and leakage impedance of the high-frequency transformer including the power supply line, and distribution parameters such as parasitic capacitance and parasitic impedance of the power supply line.

[0030] The distribution parameter model establishment module is used to establish a three-capacitance equivalent distribution parameter model of the high-frequency transformer considering the stray parameters of the power supply line, and perform order reduction and splitting on this circuit model on the premise of considering that the leakage impedance is small and ignoring the capacitance between the primary and secondary windings. The three-capacitance equivalent distribution parameter model of the high-frequency transformer including the stray parameters of the power supply line is split into a primary-side capacitance loop, a secondary-side capacitance loop, and a parallel exciting branch loop. At the same time, the parallel exciting branch loop is further split into an exciting inductance loop and an exciting resistance loop.

[0031] The high-frequency oscillation analysis module is used to substitute the impedance parameters and distribution parameters of the high-frequency transformer including the power supply line extracted, and calculate the oscillation frequency and oscillation attenuation rate of the port voltage and winding current of the high-frequency transformer under the high-frequency square wave excitation.

[0032] The waveform analysis module is used to substitute the impedance parameters and distribution parameters of the high-frequency transformer including the power supply line extracted, and calculate the waveforms of the port voltage and winding current of the high-frequency transformer under the high-frequency square wave excitation for the split low-order sub-circuit loops.

[0033] Table 1 Impedance Parameters and Distribution Parameters of the High-Frequency Transformer Prototype ; Those skilled in the art can understand that the high-frequency oscillation analysis system of the high-frequency transformer and the high-frequency oscillation analysis method of the high-frequency transformer considering the stray parameters of the line under the square wave excitation can be corresponding and referred to each other.

[0034] It should be noted that any process or method description in the embodiments can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred implementation of the present invention includes additional implementations, where the functions can be executed in a manner that is not shown or discussed in sequence, including in a substantially simultaneous manner or in the reverse order according to the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention belong.

[0035] It should be noted that for the logic and / or steps in the embodiments, for example, they can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in combination with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other appropriate processing as necessary, and then stored in a computer memory.

[0036] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), and the like.

[0037] Those of ordinary skill in the art of this technology can understand that all or part of the steps for implementing the methods of the above embodiments can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0038] In addition, each functional module in the embodiments of the present invention may be integrated into one processing module, may exist physically alone for each module, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0039] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, or the like.

[0040] The above embodiments have described the technical solutions of the present invention in detail. Obviously, the present invention is not limited to the described embodiments. Based on the embodiments of the present invention, those skilled in the art can also make various changes accordingly, but any changes equivalent or similar to the present invention belong to the scope of protection of the present invention.

[0041] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

Claims

1. A method for analyzing high-frequency oscillation of a high-frequency transformer under square wave excitation taking into account line stray parameters, characterized in that: The steps include: Obtain impedance parameters of high frequency transformer; Obtain the distributed parameters of the high-frequency transformer; According to the impedance parameters and the distributed parameters, an equivalent distributed parameter circuit model of a high-frequency transformer taking into account the stray parameters of the power supply line is established; The equivalent distributed parameter circuit model is decomposed by reducing the order to obtain a primary capacitor loop sub-circuit model, a secondary capacitor loop sub-circuit model and a parallel excitation branch loop sub-circuit model; The capacitance voltage expression and the current expression of the primary capacitance loop and the secondary capacitance loop are obtained by analytical calculation; The parallel excitation branch is decomposed into an excitation inductance circuit and an excitation resistance circuit, and the current expressions of the excitation inductance circuit and the excitation resistance circuit are obtained; The high-frequency square wave voltage is input as the excitation into the reduced-order model. The port voltage and no-load current waveforms taking into account the parasitic parameters of the high-frequency transformer are obtained according to the reduced-order model expression, and the high-frequency oscillation mechanism of the high-frequency transformer is analyzed.

2. The analysis method according to claim 1, characterized in that When establishing the equivalent distributed parameter circuit model of the high-frequency transformer taking into account the stray parameters of the power supply line, the distributed capacitance between the primary and secondary windings is ignored.

3. The analysis method according to claim 1, characterized in that The high-frequency transformer equivalent distributed parameter circuit model includes power supply line resistance and parasitic inductance.

4. The analysis method according to claim 1, characterized in that The reduced-order split primary capacitor sub-circuit is in the form of a series branch, and the capacitor element is the primary winding inter-turn capacitor; the secondary capacitor sub-circuit is in the form of a series branch, and the capacitor element is the secondary winding inter-turn capacitor; the excitation branch circuit is in the form of a parallel branch.

5. The analysis method according to claim 1, characterized in that The capacitance voltage expression of the primary capacitance loop and the secondary capacitance loop is: ； ； ； in, u C (t) represents the capacitor voltage, u 1(t) represents the capacitive voltage forcing component associated with the applied excitation, u 2(t) represents the free component of the capacitor voltage related to the initial state of the capacitor, U 0 represents the amplitude of the square wave voltage, r , l and C s Represent the total resistance, total inductance and total capacitance in the loop respectively; for the sub-circuit loop containing the primary capacitor, r Represents the resistance of the power supply line, l Represents the stray inductance of the power supply line, C s Represents the distributed capacitance of the primary winding; for the sub-circuit loop containing the secondary capacitance, r Represents the sum of the resistance of the power supply line and the transformer winding resistance, l Indicates the stray inductance of the power supply line l The sum of the leakage inductance of the winding, C s Represents the distributed capacitance of the secondary winding.

6. The analysis method according to claim 1, characterized in that The current expression of the primary capacitor loop and the secondary capacitor loop is: ； ； in, i C (t) is the current in the capacitor branch, i 1(t) represents the capacitive current forcing component associated with the applied excitation, i 2(t) represents the free component of the capacitor current related to the initial state of the capacitor.

7. The analysis method according to claim 1, characterized in that The current expression of the excitation inductance circuit and the excitation resistance circuit is: ； in, i 1(t) represents the current in the excitation inductance circuit, i 2(t) represents the current in the excitation resistance circuit, L m , L σ are the magnetizing inductance and winding leakage inductance respectively, R m , R w are the field resistance and winding resistance respectively.

8. A high-frequency transformer high-frequency oscillation analysis system for high-frequency square wave excitation and power supply line stray parameters, characterized in that: include: Parameter acquisition module, distributed parameter model building module, high-frequency oscillation analysis module and waveform analysis module; A parameter acquisition module, used to acquire impedance parameters of the high-frequency transformer and to acquire distribution parameters of the high-frequency transformer; A distributed parameter model establishment module is used to establish an equivalent distributed parameter model of a high-frequency transformer taking into account the stray parameters of the power supply line according to the impedance parameters and the distributed parameters, and to reduce the order of the circuit model under the premise of ignoring the capacitance between the primary and secondary windings, and to split the three-capacitor equivalent distributed parameter model of the high-frequency transformer taking into account the stray parameters of the power supply line into a primary capacitance circuit, a secondary capacitance circuit and a parallel excitation branch circuit; at the same time, the parallel excitation branch circuit is further split into an excitation inductance circuit and an excitation resistance circuit; The high-frequency oscillation analysis module is used to substitute the extracted impedance parameters and distribution parameters of the high-frequency transformer including the power supply line, and calculate the oscillation frequency and oscillation attenuation speed of the high-frequency transformer port voltage and winding current under high-frequency square wave excitation; The waveform analysis module is used to substitute the extracted impedance parameters and distribution parameters of the high-frequency transformer including the power supply line, and calculate the waveforms of the high-frequency transformer port voltage and winding current under high-frequency square wave excitation of the split low-order sub-circuit loop.

9. The analysis system according to claim 8, characterized in that The oscillation frequency and oscillation attenuation speed of the high-frequency transformer port voltage and winding current under the high-frequency square wave excitation are specifically: ； in, r , l and C s Represent the total resistance, total inductance and total capacitance in the sub-circuit loop respectively; for the sub-circuit loop containing the primary capacitor, r Represents the resistance of the power supply line, l Represents the stray inductance of the power supply line, C s Represents the distributed capacitance of the primary winding; for the sub-circuit loop containing the secondary capacitance, r Represents the sum of the resistance of the power supply line and the transformer winding resistance, l It represents the sum of the stray inductance of the power supply line and the leakage inductance of the transformer winding. C s Represents the distributed capacitance of the secondary winding; The high-frequency oscillation analysis module obtains the high-frequency oscillation frequency and oscillation attenuation speed of the primary port voltage of the high-frequency transformer under high-frequency square wave excitation by substituting the circuit parameters of the primary capacitor loop; and obtains the high-frequency oscillation frequency and oscillation attenuation speed of the secondary port voltage by substituting the circuit parameters of the secondary capacitor loop.

10. The analysis system according to claim 8, characterized in that The waveform analysis module is for the primary capacitor sub-loop and the secondary capacitor sub-loop, and the analytical expressions of the capacitor voltage and the loop current are specifically: ； ； in, u 1(t), i 1(t) represents the current forcing component associated with the applied excitation, u 2(t), i 2(t) represents the free components of capacitor voltage and current related to the initial state of the capacitor; r , l and C s They represent the total resistance, total inductance and total capacitance in the sub-circuit loop respectively; for the sub-circuit loop containing the primary capacitor, r represents the resistance of the power supply line, l Represents the stray inductance of the power supply line, C s Represents the distributed capacitance of the primary winding; for the sub-circuit loop containing the secondary capacitance, r Represents the sum of the resistance of the power supply line and the transformer winding resistance, l It represents the sum of the stray inductance of the power supply line and the leakage inductance of the winding. C s Represents the distributed capacitance of the secondary winding; U 0 represents the amplitude of the square wave voltage, and the expressions of α, β and θ are as follows: ； For the parallel excitation branch circuit, after further splitting it into the excitation inductance circuit and the excitation resistance circuit, the analytical expression of its circuit current is as follows: ； in, i 1(t) represents the current in the excitation inductance circuit, i 2(t) represents the current in the excitation resistance circuit, L m , L σ are the magnetizing inductance and winding leakage inductance respectively, R m , R w are the field resistance and winding resistance respectively.

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