Transient impact influence power electronic device prediction model based on broadband modeling

Abstract

The invention relates to the technical field of electromagnetic interference filtering, in particular to a transient impact influence power electronic device prediction model based on broadband modeling. The system comprises a parameter analysis module, a platform building module, an equivalent model module, a voltage derivation module and a prediction verification module. The high-frequency parasitic inductance of an input wire and the ground parasitic capacitance of the converter are accurately measured through the parameter analysis module, the platform building module builds a DC / DC converter test platform based on a linear impedance network, and the equivalent model module builds an equivalent transient impact behavior model based on the substitution theorem. The voltage derivation module determines a voltage relation between the voltage at the two ends of the MOSFET and the transient impact signal, the prediction verification module predicts the signal of the voltage at the two ends of the MOSFET, the harmonic amplitude of the transient impact signal is obtained, and the accuracy and reliability of the model in the broadband range are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic interference filtering, in particular to a transient impact influence power electronic device prediction model based on wideband modeling. BACKGROUND

[0002] With the transformation of global energy structure and the enhancement of environmental protection awareness, new energy power generation technology has developed rapidly. The widespread application of renewable energy such as wind and solar energy has promoted the popularization of photovoltaic inverter systems. These devices play an important role in improving energy utilization efficiency and reducing carbon emissions. However, photovoltaic inverter systems face complex electromagnetic environments during operation, and the problem of electromagnetic interference of sensitive equipment inside the system by transient impact is increasingly prominent.

[0003] Transient impacts such as lightning and fast transient overvoltage (VFTO) not only interfere with the normal operation of power electronic devices, but also can cause damage to equipment and even trigger system failures. Therefore, studying the mechanism of electromagnetic interference of photovoltaic inverter systems by transient impact and proposing effective protection measures are of great significance to improve the reliability and stability of the system.

[0004] With the rapid development of new energy power generation technology, new energy power electronic devices such as photovoltaic inverter systems have been widely used, but the problem of electromagnetic interference of sensitive equipment inside the system by transient impact (such as lightning, fast transient overvoltage, etc.) is increasingly prominent. Silicon carbide (SiC) devices have become an ideal choice to replace silicon (Si) devices due to their performance advantages, but their faster switching speed can lead to higher electromagnetic interference, resulting in switching oscillation and voltage overshoot, causing system instability. At the same time, external transient impact can be coupled to the system through the grounding circuit, causing ground potential rise or imbalance, affecting electronic components, and even damaging equipment. Therefore, we propose a transient impact influence power electronic device prediction model based on wideband modeling. SUMMARY

[0005] The purpose of the present application is to solve the problem of electromagnetic interference of sensitive equipment inside the system by transient impact (such as lightning, fast transient overvoltage, etc.). Silicon carbide (SiC) devices have become an ideal choice to replace silicon (Si) devices due to their performance advantages, but their faster switching speed can lead to higher electromagnetic interference, resulting in switching oscillation and voltage overshoot, causing system instability. At the same time, external transient impact can be coupled to the system through the grounding circuit, causing ground potential rise or imbalance, affecting electronic components, and even damaging equipment.

[0006] To achieve the above purpose, the present application provides a transient impact influence power electronic device prediction model based on wideband modeling, which includes a parameter analysis module, a platform building module, an equivalent model module, a voltage derivation module and a prediction verification module.

[0007] The parameter analysis module analyzes the generation and conduction mechanism of the transient impulse signal, precise measurement of the input wire high-frequency parasitic inductance and the transformer parasitic capacitance to ground is realized by using ANSYS and impedance network analyzer, the platform building module constructs a DC / DC converter test platform based on linear impedance network, the equivalent model module establishes an equivalent transient impulse behavior model based on the replacement theorem according to the transient impulse signal propagation mechanism in new energy power electronic devices, the voltage derivation module analyzes the influence of the transient impulse signal on the internal MOSFET of the new energy power electronic device converter, determines the voltage relationship between the MOSFET and the transient impulse signal, and the prediction verification module brings the transient ground potential rise signal into the MOSFET voltage relationship affected by the transient impulse of the sensitive equipment in the new energy power electronic device, predicts the signal of the voltage across the MOSFET, and obtains the harmonic amplitude of the transient impulse signal.

[0008] Compared with the prior art, the beneficial effects of the present application are:

[0009] 1. The transient impulse influence power electronic device prediction model based on wideband modeling, through the parameter analysis module, the high-frequency parasitic parameters (such as input wire parasitic inductance and transformer parasitic capacitance to ground) are accurately identified and measured, and combined with the simplified analysis of the transient ground potential rise signal propagation path by the equivalent model module, the mechanism of the transient impulse coupling to the power electronic device through the grounding network can be clearly revealed, and the accurate positioning of the transient impulse influence can be realized.

[0010] 2. The platform building module constructs a test platform based on linear impedance network (LISN), which completely simulates the actual working environment of new energy power electronic devices, and each module has clear division (parameter analysis, platform building, model equivalence, voltage derivation, prediction verification), which can be operated as an independent link, and is convenient for reproduction and implementation in engineering application.

[0011] 3. The equivalent model module replaces the complex elements in the circuit with simple equivalent elements based on the replacement theorem, focuses on the affected situation of the key sensitive equipment control tube Q1, simplifies the analysis difficulty of the transient ground potential rise path, the voltage derivation module establishes the quantitative relationship between the transient ground potential rise signal (Vex) and the switch tube voltage (VQ1), realizes the leap from qualitative analysis to quantitative prediction; the prediction verification module substitutes the double exponential lightning signal into the model, and compares it with the Pspice simulation result, ensures the accuracy and reliability of the model in the wide frequency range, and provides a strong basis for transient impulse protection design.

[0012] As a further improvement of the technical solution, the parameter analysis module determines the main high-frequency parasitic parameters in the new energy power electronic device by analyzing the generation and conduction mechanism of the transient impulse signal, determining the path of the transient ground potential rise caused by the transient impulse through the grounding network, and affecting the internal sensitive equipment of the new energy power electronic device through the parasitic capacitance to ground of the new energy power electronic device.

[0013] As a further improvement of the technical solution, the platform building module constructs a DC / DC converter test platform based on a linear impedance network, including a direct current source VDC, a parasitic capacitance CSG and a load RL.

[0014] The direct current source VDC is connected to the DC / DC converter, the output of the DC / DC converter is connected to the load RL, one end of the parasitic capacitance CSG is connected to the half-bridge midpoint of the DC / DC converter, and the other end of the parasitic capacitance CSG is grounded.

[0015] As a further improvement of the technical solution, the platform building module includes a DC / DC converter, wherein the DC / DC converter includes a control tube Q1, a freewheeling tube Q2 and a filter inductor L.

[0016] The drain electrode of the control tube Q1 is connected to one end of the filter inductor L and the source electrode of the freewheeling tube Q2, the other end of the filter inductor L is connected to a wire inductor L1, the other end of the wire inductor L1 is connected to one end of an input capacitor Cin, the other end of the input capacitor Cin is connected to a wire inductor L2, the other end of the wire inductor L2 is connected to the source electrode of the control tube Q1, the drain electrode of the freewheeling tube Q2 is connected to one end of a capacitor C0, and the other end of the capacitor C0 is connected to one end of a resistor R0.

[0017] The beneficial effects of the above further improvement are that the generation and conduction mechanism of the transient impulse signal can be analyzed to determine the path of the transient ground potential rise caused by the transient impulse through the grounding network and affecting the internal sensitive equipment through the parasitic capacitance to ground; the input wire high-frequency parasitic inductance and the converter parasitic capacitance to ground can be accurately measured using ANSYS and an impedance network analyzer, and the key parameters of the transient impulse conduction can be obtained to provide accurate data for modeling; the DC / DC converter test platform based on the linear impedance network can simulate the actual working environment, including the direct current source, the parasitic capacitance, the load and other elements, and ensure that the model is close to the actual scene.

[0018] As a further improvement of the technical solution, when the equivalent model module establishes the equivalent transient impulse behavior model, the actual circuit complex elements are replaced by simpler equivalent elements using the substitution theorem, and for the DC / DC converter, the influence of the control tube Q1 is mainly considered.

[0019] As a further improvement of the technical solution, the equivalent model module uses the equivalent circuit model of the DC / DC converter, simplifies the complex transient ground potential rise path, and focuses on the propagation mechanism of the transient ground potential rise signal.

[0020] As a further improvement of the technical solution, the equivalent model module opens the current source Id and ignores its contribution to the voltage signal across the control tube Q1, and the impedance Rds,on represents the impedance model of the switch tube Q1 across the control tube Q1 under the influence of the transient ground potential rise signal, and further equivalent analyzes the influence of the transient ground potential rise signal on the boost converter electromagnetic interference model.

[0021] The beneficial effects of the above further improvement are that the complex elements (such as field effect tubes Q1, Q2) of the actual circuit in the new energy power electronic device are replaced by simpler equivalent elements, the analysis difficulty of the transient ground potential rise signal through the closed-loop conduction path of "ground network → converter-to-ground parasitic capacitor CSG → converter" is simplified, the core influence of the transient impact signal on the control tube Q1 sensitive equipment is focused, the propagation mechanism of the transient ground potential rise signal is clearly analyzed, and the key parasitic parameters and coupling effects are retained, so that the model can reflect the real physical process and facilitate the derivation of the quantitative relationship between the transient ground potential rise signal and the voltage of the sensitive equipment.

[0022] As a further improvement of the technical solution, the voltage derivation module uses Vex instead of the transient ground potential rise signal caused by the transient impact, the transient ground potential rise signal Vex is the voltage change in the process of the replaced transient ground potential rise signal, VQ1 represents the voltage waveform of the switch tube during conduction and turn-off, Vds is the voltage change of the switch device of the new energy power electronic device caused by the replaced transient ground potential rise signal change process, and the relationship between the transient ground potential rise signal Vex and VQ1 is determined.

[0023] As a further improvement of the technical solution, the prediction verification module substitutes the double exponential lightning signal into the transient impact model, and compares it with the measured voltage spectrum across the MOSFET inside the converter in the Pspice simulation to verify the prediction result.

[0024] As a further improvement of the technical solution, the prediction verification module determines the spectral characteristics of the double exponential lightning signal and uses it as an input parameter to analyze its influence on the MOSFET inside the DC / DC converter of the new energy power electronic device.

[0025] The above further improved beneficial effect is that the transient impact generated by the real lightning is simulated by using the definite spectrum characteristics, the accuracy and reliability of the model in the wide frequency range can be directly evaluated by comparing the model predicted MOSFET two-terminal voltage spectrum with the measured spectrum in the Pspice simulation; meanwhile, the influence of the transient impact on the internal sensitive equipment of the new energy power electronic device can be identified in the design stage, the analysis process of the complex circuit is simplified, and the basis for the model optimization and electromagnetic compatibility design is provided.

[0026] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall process of the present application;

[0028] Figure 2 It is a schematic diagram of the influence of transient impact on a new energy power electronic device of the present application;

[0029] Figure 3 It is a schematic diagram of the influence of transient ground potential rise electromagnetic interference Vex on sensitive devices of a DC / DC converter of the present application;

[0030] Figure 4 It is an electromagnetic interference equivalent model diagram of the influence of transient ground potential rise electromagnetic interference Vex signal on a synchronous converter of the present application;

[0031] Figure 5 It is an equivalent model diagram of the transient ground potential rise electromagnetic interference of the present application;

[0032] Figure 6 It is a transient ground potential rise signal simulated in Pspice of the present application, (a) is a transient ground potential rise signal time-domain waveform, and (b) is a transient ground potential rise signal frequency-domain waveform diagram;

[0033] Figure 7 It is a waveform of the influence of the transient ground potential rise signal simulated in Pspice on the control tube Q1 of the present application, (a) is a Q1 two-terminal voltage time-domain signal, and (b) is a Q1 two-terminal voltage frequency-domain signal diagram;

[0034] Figure 8 It is a Q1 two-terminal frequency-domain waveform diagram of the boost converter under the predicted transient ground potential rise signal simulated in Pspice of the present application.

[0035] The meanings of various reference numerals in the drawings are as follows:

[0036] 100, parameter analysis module; 200, platform building module; 300, equivalent model module; 400, voltage derivation module; 500, prediction verification module. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0038] At present, the problem of electromagnetic interference of transient impulse (such as lightning, fast transient overvoltage, etc.) on internal sensitive equipment is increasingly prominent. Silicon carbide (SiC) devices become an ideal choice to replace silicon (Si) devices due to their performance advantages, but their faster switching speed will lead to higher electromagnetic interference, resulting in switching oscillation and voltage overshoot, and causing system instability. At the same time, external transient impulse will be coupled to the system through the ground return circuit, causing ground potential rise or imbalance, affecting electronic components, and even damaging equipment.

[0039] Therefore, the present application proposes that the parameter analysis module accurately measures the high-frequency parasitic inductance of the input lead and the parasitic capacitance of the converter to ground, the platform building module constructs a DC / DC converter test platform based on a linear impedance network, the equivalent model module establishes an equivalent transient impulse behavior model based on the substitution theorem, the voltage derivation module analyzes the influence of the transient impulse signal on the MOSFET inside the new energy power electronic device converter, determines the voltage relationship between the MOSFET voltage and the transient impulse signal, and the prediction verification module predicts the signal of the MOSFET voltage to obtain the harmonic amplitude of the transient impulse signal.

[0040] Specifically as follows:

[0041] Please refer to Figure 1 As shown in the figure, the present application provides a transient impulse influence power electronic device prediction model based on wideband modeling, which includes a parameter analysis module 100, a platform building module 200, an equivalent model module 300, a voltage derivation module 400 and a prediction verification module 500.

[0042] The parameter analysis module 100 analyzes the generation and propagation mechanism of transient impulse signals, and uses ANSYS and an impedance network analyzer to accurately measure the high-frequency parasitic inductance of the input conductor and the parasitic capacitance of the converter to ground. The platform construction module 200 constructs a DC / DC converter test platform based on a linear impedance network. The equivalent model module 300 establishes an equivalent transient impulse behavior model based on the substitution theorem according to the propagation mechanism of transient impulse signals in new energy power electronic devices. The voltage derivation module 400 analyzes the impact of transient impulse signals on the MOSFETs inside the converter of new energy power electronic devices, and determines the voltage relationship between the voltage across the MOSFETs and the transient impulse signal. The prediction and verification module 500 substitutes the transient ground potential rise signal into the voltage relationship of the sensitive MOSFETs inside the new energy power electronic device affected by the transient impulse, predicts the voltage signal across the MOSFETs, and obtains the harmonic amplitude of the transient impulse signal.

[0043] By analyzing the generation and conduction mechanism of transient ground potential rise signal, the high-frequency parasitic parameters contained in the converter control mode and its circuit model are determined, and the transient impact model of the new energy power electronic device system is obtained. The prediction model of sensitive equipment inside the new energy power electronic device system under transient impact is realized. Then, based on the established external transient impact prediction model, the MOSFET spectrum inside the new energy power electronic device under transient impact can be obtained.

[0044] In order to better determine the main high-frequency parasitic parameters in the new energy power electronic device, the parameter analysis module 100 will determine the main high-frequency parasitic parameters in the new energy power electronic device by using the transient impact to cause a transient ground potential rise through the grounding network and the transient ground potential rise signal to affect the sensitive equipment inside the new energy power electronic device through the parasitic capacitance to ground of the new energy power electronic device.

[0045] The core mechanism is clearly defined: transient impacts first cause a transient ground potential rise through the grounding network, and then affect internal sensitive equipment through the device's parasitic capacitance to ground. At the same time, using ANSYS and an impedance network analyzer, the key high-frequency parasitic parameters such as the high-frequency parasitic inductance of the input conductor (LL,PCB, LN,PCB) and the converter's parasitic capacitance to ground (CSG) are accurately measured. These parameters are the key paths for transient impact propagation. Their accurate acquisition lays a crucial data foundation for subsequent construction of equivalent models, derivation of voltage relationships, and accurate prediction of the impact of transient impacts, ensuring that the model can truly reflect the effect of transient impacts on new energy power electronic devices over a wide frequency range.

[0046] like Figure 2 As shown, the platform building module 200 constructs a DC / DC converter test platform based on a linear impedance network, including a DC source VDC, a parasitic capacitance CSG, and a load RL.

[0047] The direct current source VDC is connected to the DC / DC converter, the output of the DC / DC converter is connected to the load RL, one end of the parasitic capacitor CSG is connected to the half-bridge midpoint of the DC / DC converter, and the other end of the parasitic capacitor CSG is connected to the ground.

[0048] In the circuit, the direct current voltage VDC is input to the DC / DC converter, and the converter supplies power to the load RL after processing; the transient impulse generates a transient ground potential rise signal Vex through the grounding network, the signal is injected through the parasitic capacitor CSG of the new energy power electronic device, and the current Iex is induced, which interferes with the internal circuit of the DC / DC converter, affects the conversion and transmission of the DC / DC converter, and simulates the effect of the transient impulse on the device, which is used to analyze the working state and affected mechanism of the device under the transient impulse.

[0049] As shown in Figure 3 , wherein the platform building module 200 includes a DC / DC converter, wherein the DC / DC converter includes a control tube Q1, a freewheeling tube Q2 and a filter inductor L;

[0050] The drain electrode of the control tube Q1 is connected to one end of the filter inductor L, and the source electrode of the freewheeling tube Q2 is connected thereto, the other end of the filter inductor L is connected to a wire inductor L1, the other end of the wire inductor L1 is connected to one end of an input capacitor Cin, the other end of the input capacitor Cin is connected to a wire inductor L2, the other end of the wire inductor L2 is connected to the source electrode of the control tube Q1, the drain electrode of the freewheeling tube Q2 is connected to one end of a capacitor C0, and the other end of the capacitor C0 is connected to one end of a resistor R0.

[0051] In the circuit, the direct current voltage VDC is filtered through the input capacitor Cin, in the boost circuit, when the control tube Q1 is turned on, the power supply forms a loop through the inductor L1, the inductor L and the control tube Q1, and the inductor L stores energy; when the control tube Q1 is turned off, the inductor L releases energy to the load R0 through the freewheeling diode (the diode of the freewheeling tube Q2) and the output capacitor Co to realize voltage boosting. At the same time, the ground potential rise signal Vex generated by the transient impulse is injected into the circuit through the parasitic capacitor Csg, and the control tube Q1, the freewheeling tube Q2 and other devices are disturbed through the inductor L2 parasitic parameter, which can be used to analyze the influence of the transient impulse on the boost type DC / DC converter.

[0052] In order to better equivalent the transient impulse behavior model, wherein when the equivalent model module 300 establishes the equivalent transient impulse behavior model, the actual circuit complex element is replaced by a simpler equivalent element using the substitution theorem, and for the DC / DC converter, the influence of the control tube Q1 is mainly considered;

[0053] The complex elements in the actual circuit, such as the control tube Q1 and the freewheeling tube Q2, are replaced by simpler equivalent elements, which help us simplify the circuit analysis and more accurately predict the behavior of the transient ground potential rise signal. In the DC / DC converter, the control tube Q1 is the switching element of the control signal, so when building a behavior model of the transient ground potential rise affecting the DC / DC converter, the main consideration is the impact of the control tube Q1.

[0054] In order to better establish an equivalent circuit model of the DC / DC converter, the equivalent model module 300 uses the equivalent circuit model of the DC / DC converter to simplify the complex transient ground potential rise path and focus on analyzing the propagation mechanism of the transient ground potential rise signal.

[0055] As shown in Figure 4 , the equivalent circuit model of the DC / DC converter is shown, which can help us simplify the complex transient ground potential rise path and focus on analyzing the propagation mechanism of the transient ground potential rise signal. The transient ground potential rise signal is coupled with the parasitic capacitance, inductance and other elements in the circuit to form a noise source and a conduction path, and the loop is: transient ground potential rise signal-CSG-Q1-Zgnd-transient ground potential rise signal. The equivalent circuit model provides a clear framework for subsequent EMI analysis and noise suppression;

[0056] The DC voltage VDC is filtered by the input capacitor Cin and then enters the boost circuit composed of inductance L, equivalent resistance RDS,on, etc. The current source IDS simulates the operation of the switch tube Q2 to control energy storage and release to achieve voltage boost. The output capacitor Co supplies power to the load Ro. At the same time, the transient ground potential rise signal Vex is injected into the circuit through the parasitic capacitance Csg and the parasitic inductance Lboost,PCB1, Lboost,PCB2, and forms an interference path through the impedance Zgnd, which can be used to analyze the electromagnetic interference and voltage variation characteristics of the boost converter under transient impact.

[0057] In order to establish a behavior model of the voltage across the control tube Q1 and the transient ground potential rise signal in the boost converter, the equivalent model module 300 opens the current source Id and ignores its contribution to the voltage signal across the control tube Q1. The impedance Rds,on represents the impedance model of the switch tube Q1 across the control tube Q1 under the influence of the transient ground potential rise signal, which further equivalent analyzes the influence of the transient ground potential rise signal on the electromagnetic interference model of the boost converter.

[0058] With the current source Id open-circuited and its contribution to the voltage signal across the control transistor Q1 ignored, the impedance Rds,on represents the impedance model across the control transistor Q1 under the influence of the transient ground potential rise signal. In the frequency band from 150kHz to 30MHz, since the fundamental frequency of the transient ground potential rise signal is much lower than 150kHz to 30MHz, the impedance of the input capacitor Cin cannot be ignored.

[0059] like Figure 5 As shown, the DC-side voltage is filtered by Cin. In the path formed by Lboost,PCB1, inductor L, and impedance RDS,on, the inductor L stores and releases energy to achieve the boost function. The impedance RDS,on simulates the on-resistance of the control transistor Q1, and VQ1 at its two ends reflects the voltage of the control transistor Q1. At the same time, the transient impact generates a Vex signal which is injected through the parasitic capacitance Csg. With the help of Lboost,PCB2 and impedance Zgnd, an interference path is formed. The influence of transient ground potential rise on the switching transistor voltage can be analyzed, which can be used to study the characteristics of the boost circuit under transient impact.

[0060] In order to better determine the relationship between the transient ground potential rise signal Vex and VQ1, the voltage derivation module 400 uses Vex to replace the transient ground potential rise signal caused by the transient impact. The transient ground potential rise signal Vex is the voltage change during the process of replacing the transient ground potential rise signal, VQ1 represents the voltage waveform during the switching process of the switch tube, and Vds is the voltage change of the switching device of the new energy power electronic device caused by the change of the replaced transient ground potential rise signal, so as to determine the relationship between the transient ground potential rise signal Vex and VQ1.

[0061] Determine the relationship between the voltage signal across Q1 transistor and the transient ground potential rise signal in the boost DC / DC converter:

[0062]

[0063] Zboost is the parallel connection of the impedances on the L and N lines with the equivalent impedance RDS,on of the MOSFET control transistor, as shown in the following formula:

[0064]

[0065] Where, Vex: Transient potential rise signal, simulating the voltage disturbance caused by transient impacts such as lightning strikes on the grounding network; Vds: Voltage change of the DC / DC converter switch tube Q1; Zboost: Equivalent impedance of the Boost circuit side; ZCsg: Impedance of the parasitic capacitor Csg of the converter; Zgnd: Equivalent impedance of the grounding network; VQ1: Voltage waveform of the switch tube Q1 under normal operation; Zboost is the parallel connection of the impedance on the L and N lines and the equivalent impedance RDS,on of the MOSFET control tube, and VQ1 is the voltage waveform of the switch tube Q1 of the new energy power electronic device under normal operation.

[0066] In order to better verify the prediction results, the prediction verification module 500 substitutes the double exponential lightning signal into the transient impact model, and compares it with the measured voltage spectrum of the MOSFET inside the converter to verify the prediction results;

[0067] Substitute the double exponential lightning signal for the noise source. The double exponential lightning signal as a noise source can help us simulate the high-frequency voltage waveform caused by lightning signals and determine its impact on the system through spectral analysis. Once the double exponential lightning signal is predicted through the transient impact model, we need to further verify the accuracy of the prediction results. This is usually done by comparing with the simulation results. By measuring the voltage spectrum of the internal MOSFET of the converter in the simulation environment and comparing it with the model prediction results, the accuracy and reliability of the model under different working conditions can be evaluated. If the prediction results are close to the simulation results, it means that the model is effective; otherwise, the model needs to be further adjusted and optimized, which may include re-evaluating the spectral characteristics of the double exponential lightning signal, correcting the parameters of the parasitic elements, or modeling the MOSFET in more detail.

[0068] In order to be able to, the prediction verification module 500 analyzes the influence of the double exponential lightning signal on the MOSFET inside the DC / DC converter of the new energy power electronic device by determining the spectral characteristics of the double exponential lightning signal and taking it as an input parameter;

[0069] Approximate the lightning signal noise by the known double exponential lightning signal model. In this process, the spectral characteristics of the double exponential lightning signal can be given in advance and taken as an input parameter to analyze its influence on the MOSFET of the Boost DC / DC converter inside the new energy power electronic device. The double exponential lightning signal usually has a clear spectral composition.

[0070] The experimental parameters are as follows:

[0071]

[0072]

[0073] As Figure 6 shown, Figure 6 (a) time-domain waveform and Figure 6 (b) frequency-domain waveform, the complete characteristics of the transient potential rise signal can be obtained: in the time domain, the dynamic impact parameters such as peak value, rise / fall time, and duration can be intuitively known, reflecting the impact strength and instantaneous action characteristics; in the frequency domain, the main harmonic frequency and the proportion of high-frequency components of the signal energy distribution can be clearly known, revealing the wideband interference law. The combination of the two can not only verify the accuracy of the transient impact modeling, but also provide a basis for power electronic device anti-interference design (such as filter selection and protection device selection), and realize comprehensive analysis of transient impact from “dynamic behavior” to “frequency influence”.

[0074] As Figure 7 shown, Figure 7 (a) the time-domain dynamic characteristics of the voltage across Q1 of the boost converter under the transient ground potential rise signal, such as peak value and fluctuation duration, can be obtained, reflecting the instantaneous impact of the transient impact on the voltage of Q1; combined with Figure 7 (b) the frequency distribution of the voltage can be clearly known, and the energy concentration frequency band and high-frequency interference components can be known, and the combination of the two can analyze the voltage stress and electromagnetic interference law of Q1 under the transient impact, verify the accuracy of the voltage relationship in the transient impact influence model, and provide a basis for optimizing the anti-interference design of the converter and ensuring the reliable operation of Q1.

[0075] As Figure 8 shown, the frequency-domain distribution characteristics of the voltage across Q1 of the boost converter under the transient ground potential rise signal can be intuitively obtained, and information such as the frequency interval of energy concentration and the amplitude of each frequency component can be obtained, which can be used to analyze the high-frequency interference degree of Q1 under the transient impact and verify the accuracy of the prediction model based on wideband modeling. From the prediction results, the relationship between the transient ground potential rise signal and the voltage signal across Q1 of the boost converter is correct and reasonable.

[0076] In summary, the working principle of the present scheme is as follows:

[0077] The transient impact influence power electronic device prediction model based on wideband modeling can accurately identify and measure high-frequency parasitic parameters (such as input wire parasitic inductance and converter parasitic capacitance to ground) through the parameter analysis module 100, and can clearly reveal the mechanism of the transient impact coupling to the power electronic device through the grounding network by combining the simplified analysis of the transient ground potential rise signal propagation path by the equivalent model module 300, and can realize accurate positioning of the transient impact influence;

[0078] The platform building module 200 builds a test platform based on a linear impedance network (LISN), completely simulates an actual working environment of a new energy power electronic device, and has clear division of labor (parameter analysis, platform building, model equivalence, voltage derivation, prediction verification), so that a complex transient impact prediction process is disassembled into operable independent links, and reproduction and implementation in engineering application are facilitated;

[0079] The equivalent model module 300 replaces complex elements in the circuit with simple equivalent elements based on the substitution theorem, focuses on the affected situation of the key sensitive device control tube Q1, and simplifies the analysis difficulty of the transient ground potential rise path, the voltage derivation module 400 establishes a quantitative relationship between the transient ground potential rise signal (Vex) and the switch tube voltage (VQ1), realizes the leap from qualitative analysis to quantitative prediction, the prediction verification module 500 substitutes the double exponential lightning signal into the model and compares it with the Pspice simulation result, and ensures the accuracy and reliability of the model in a wide frequency range, and provides a strong basis for transient impact protection design.

[0080] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A predictive model for the transient impact on power electronic devices based on broadband modeling, characterized in that: It includes a parameter analysis module (100), a platform construction module (200), an equivalent model module (300), a voltage derivation module (400), and a prediction verification module (500); The parameter analysis module (100) analyzes the generation and propagation mechanism of transient impact signals, and uses ANSYS and impedance network analyzer to accurately measure the high-frequency parasitic inductance of the input conductor and the parasitic capacitance of the converter to ground. The platform construction module (200) constructs a DC / DC converter test platform based on a linear impedance network. The equivalent model module (300) establishes an equivalent transient impact behavior model based on the substitution theorem according to the propagation mechanism of transient impact signals in new energy power electronic devices. The voltage derivation module (400) analyzes the impact of transient impact signals on the MOSFETs inside the converter of new energy power electronic devices, and determines the voltage relationship between the voltage across the MOSFETs and the transient impact signal. The prediction and verification module (500) introduces the transient ground potential rise signal into the voltage relationship of the sensitive equipment MOSFETs inside the new energy power electronic device affected by the transient impact, predicts the voltage signal across the MOSFETs, and obtains the harmonic amplitude of the transient impact signal.

2. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 1, characterized in that: The parameter analysis module (100) will determine the main high-frequency parasitic parameters in the new energy power electronic device by analyzing the transient impact caused by the transient ground potential rise through the grounding network and the transient ground potential rise signal affecting the sensitive equipment inside the new energy power electronic device through the parasitic capacitance to ground of the new energy power electronic device.

3. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 1, characterized in that: The platform building module (200) constructs a DC / DC converter test platform based on a linear impedance network, including a DC source VDC, a parasitic capacitance CSG, and a load RL; The DC source VDC is connected to the DC / DC converter, the output of the DC / DC converter is connected to the load RL, one end of the parasitic capacitor CSG is connected to the midpoint of the half-bridge of the DC / DC converter, and the other end of the parasitic capacitor CSG is grounded.

4. The transient impact prediction model for power electronic devices based on broadband modeling according to claim 3, characterized in that: The platform construction module (200) includes a DC / DC converter, wherein the DC / DC converter includes a control transistor Q1, a freewheeling transistor Q2, and a filter inductor L; The drain of the control transistor Q1 is connected to one end of the filter inductor L and to the source of the freewheeling transistor Q2. The other end of the filter inductor L is connected to the wire inductor L1. The other end of the wire inductor L1 is connected to one end of the input capacitor Cin. The other end of the input capacitor Cin is connected to the wire inductor L2. The other end of the wire inductor L2 is connected to the source of the control transistor Q1. The drain of the freewheeling transistor Q2 is connected to one end of the capacitor C0. The other end of the capacitor C0 is connected to one end of the resistor R0.

5. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 1, characterized in that: When establishing the equivalent transient impact behavior model, the equivalent model module (300) uses the substitution theorem to replace the complex components in the actual circuit with simpler equivalent components. For DC / DC converters, the influence of the control transistor Q1 is mainly considered.

6. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 5, characterized in that: The equivalent model module (300) uses the equivalent circuit model of the DC / DC converter to simplify the complex transient ground potential rise path and focus on analyzing the propagation mechanism of the transient ground potential rise signal.

7. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 6, characterized in that: The equivalent model module (300) opens the current source Id and ignores its contribution to the voltage signal across the control transistor Q1. The impedance Rds,on represents the impedance model across the control transistor Q1 under the influence of the transient ground potential rise signal. Further equivalent analysis is performed on the electromagnetic interference model of the boost converter affected by the transient ground potential rise signal.

8. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 1, characterized in that: The voltage derivation module (400) uses Vex to replace the transient ground potential rise signal caused by the transient impact. The transient ground potential rise signal Vex is the voltage change during the process of replacing the transient ground potential rise signal. VQ1 represents the voltage waveform during the switching process of the switch tube. Vds is the voltage change of the switching device of the new energy power electronic device caused by the change of the replaced transient ground potential rise signal. The module determines the relationship between the transient ground potential rise signal Vex and VQ1.

9. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 1, characterized in that: The prediction verification module (500) substitutes the double-exponential lightning strike signal into the transient impact model and verifies the prediction results by comparing them with the voltage spectrum across the MOSFET inside the converter measured in the PSpice simulation.

10. The prediction model for transient impacts on power electronic devices based on broadband modeling according to claim 9, characterized in that: The prediction verification module (500) analyzes the impact of the double exponential lightning strike signal on the MOSFET of the DC / DC converter inside the new energy power electronic device by determining the spectral characteristics of the double exponential lightning strike signal and using it as an input parameter.

Images