Insulation space charge low-voltage side acquisition system under positive polarity square wave

Abstract

The invention provides an insulation space charge low-voltage side acquisition system under positive polarity square waves. The insulation space charge low-voltage side acquisition system comprises a signal generation unit, a voltage amplification unit, a current-limiting protection resistor, a high-voltage test branch, a signal acquisition unit, an optical fiber communication module and an upper computer, wherein the high-voltage test branch is formed by connecting a tested sample and an integrating capacitor in series; the signal acquisition unit and the optical fiber communication module are integrated on a PCB (Printed Circuit Board); according to the system, a signal generation unit and a voltage amplification unit cooperatively generate repeated square wave high voltage and apply the high voltage to a sample, a signal acquisition unit on a low-voltage side is used for extracting an analog voltage signal on an integrating capacitor, the analog voltage signal is converted into a digital signal and then is transmitted to an upper computer through optical fiber isolation, and a dynamic charge quantity waveform is obtained. The device can accurately measure the charge accumulation characteristics of the insulating material or the structure under the repeated square wave voltage, effectively evaluates the insulating performance and the deterioration degree of the sample, and has the advantages of high measurement precision, good safety, high integration level and the like.

Description

A low-voltage side acquisition system for insulating space charge under positive polarity square wave Technical Field

[0001] This application relates to the field of electrical engineering high voltage and power electronic device packaging insulation performance testing technology, specifically, to a low-voltage side acquisition system for insulation space charge under positive polarity square wave. Background Technology

[0002] With the rapid development of power electronics technology, high-voltage power conversion equipment is increasingly widely used in energy conversion and transmission. During operation, the internal insulation materials and structures of these devices are often subjected to stress from high-frequency repetitive square wave voltages. Research has found that the accumulation of space charge within the insulating medium is one of the key factors leading to insulation performance degradation, inducing partial discharge, and even causing insulation breakdown. The dynamic distribution of space charge directly alters the local electric field within the material, accelerating the insulation aging process. Therefore, accurately measuring and analyzing the space charge characteristics under repetitive square wave voltages is of significant scientific research value and engineering importance for assessing the insulation reliability of power equipment and optimizing insulation design.

[0003] Currently, significant progress has been made in space charge measurement technology, but existing research and measurement devices are mostly designed for DC or power frequency AC electric field environments. When faced with the specific condition of a positive polarity repetitive square wave voltage, existing measurement methods present numerous challenges. On the one hand, the high-frequency components of the repetitive square wave introduce severe electromagnetic interference, making it difficult to accurately extract the weak space charge signal. On the other hand, traditional measurement systems often employ direct sampling from the high-voltage side, which not only imposes extremely high voltage withstand and anti-interference requirements on the signal acquisition equipment but also poses a potential threat to the safety of testing personnel. Furthermore, existing experimental setups are often temporarily constructed from various discrete instruments, resulting in low system integration. This loose structure leads to large stray inductance and distributed capacitance in the measurement circuit, severely affecting the fidelity of signal transmission under high-frequency square waves. Simultaneously, due to the lack of a unified control platform and automated data processing methods, the testing process typically relies on manual operation, making it difficult to achieve dynamic configuration of test parameters and real-time waveform monitoring.

[0004] Therefore, this application provides a low-voltage side acquisition system for insulating space charge under positive polarity square wave to solve one of the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a low-voltage side acquisition system for insulation space charge under a positive square wave, which can solve at least one of the aforementioned technical problems. The specific solution is as follows: According to a specific embodiment of this application, in a first aspect, this application provides a low-voltage side acquisition system for insulation space charge under a positive square wave, comprising: a signal generator for outputting a positive repetitive square wave low-voltage signal; a voltage amplifier, with its input terminal connected to the signal generator, for amplifying the low-voltage signal and outputting a positive repetitive square wave high-voltage signal; a current-limiting protection resistor, one end of which is connected to the output terminal of the voltage amplifier; and a high-voltage test branch, consisting of a test sample and an integrating capacitor connected in series, the other end of which is connected to the input terminal of the test sample, and the output terminal of the test sample is connected to the integrating capacitor. One end of the integrating capacitor is connected to the input terminal of the signal acquisition unit, and the other end of the integrating capacitor is grounded; the signal acquisition unit, integrated on the PCB board, is used to extract the analog voltage signal reflecting the dynamic charge of the test sample on the integrating capacitor through a voltage follower, and convert the analog voltage signal into a digital voltage signal; the fiber optic communication module, integrated on the PCB board, is used to transmit the digital voltage signal with electrical isolation; the host computer is connected to the signal generator, the voltage amplifier and the fiber optic communication module respectively, and is used to remotely configure test parameters and process the received data and display the waveform in real time.

[0006] In one embodiment, the high-voltage test branch further includes a high-voltage electrode device with a three-electrode structure, which consists of a counter electrode, a measuring electrode, and a protection electrode.

[0007] In one embodiment, the counter electrode is connected to the output terminal of the voltage amplifier, the measuring electrode is connected to one end of the integrating capacitor, and the protection electrode is directly grounded.

[0008] In one embodiment, the materials of the counter electrode and the measuring electrode are non-ferromagnetic metallic materials, and the surface roughness of the counter electrode and the measuring electrode is less than [amount missing]. The relative flatness is less than .

[0009] In one embodiment, if the sample under test is a silicon carbide device packaging insulation structure, the terminals at both ends of the insulation structure are respectively connected to the integrating capacitor and the current limiting protection resistor, without the need for a high-voltage electrode device.

[0010] In one embodiment, the frequency of the positive polarity repetitive square wave output by the signal generator is: The resistance value of the current limiting protection resistor is .

[0011] In one embodiment, the maximum load current of the voltage amplifier is The amplification factor of the voltage amplifier is... Adjustable between multiples.

[0012] In one embodiment, the integrating capacitor is a leakage-free current capacitor made of polypropylene, polystyrene, or polytetrafluoroethylene film, and the capacitance value of the integrating capacitor is the capacitance value of the sample under test. times.

[0013] In one embodiment, the signal acquisition unit includes a voltage follower, an analog-to-digital converter, and a microcontroller cascaded together; wherein the non-inverting input of the voltage follower is connected between the integrating capacitor and the sample under test, and the inverting input of the voltage follower is connected to the output of the voltage follower.

[0014] In one embodiment, the integrating capacitor, the signal acquisition unit, and the optical fiber communication module are integrated on the same PCB board, and the receiving port of the optical fiber communication module is electrically connected to the output terminal and control port of the microprocessor in the signal acquisition unit, respectively.

[0015] Compared with the prior art, the above-described solution of this application has at least the following beneficial effects: This application provides a low-voltage side acquisition system for insulation space charge under positive polarity square wave. By combining a signal generation unit, a voltage amplification unit, a high-voltage test branch, and a signal acquisition unit and fiber optic communication module integrated on a PCB board, it achieves accurate evaluation of insulation performance under voltage conditions simulating the actual operating conditions of silicon carbide devices. This architecture utilizes a low-voltage side acquisition method combined with fiber optic isolated transmission, ensuring the electrical safety of measurement personnel and the host computer, and effectively reducing the interference of stray circuit parameters on weak charge signals through PCB integrated design. This allows for accurate acquisition of the dynamic accumulation characteristics of space charge in samples under actual operating conditions, providing a reliable data foundation for evaluating the degree of insulation degradation of samples. Attached Figure Description

[0016] Figure 1 shows a schematic diagram of a low-voltage side acquisition system for insulating space charge under positive polarity square wave; Figure 2 shows a schematic diagram of the test results of a silicon carbide device packaging insulating material; wherein, the figures are labeled as follows: 1-host computer; 2-signal generator; 3-voltage amplifier; 4-high voltage electrode device; 5-voltage follower; 6-analog-to-digital converter; 7-microcontroller; 8-fiber optic communication module; 9-signal acquisition unit; 10-PCB board; R-current limiting protection resistor; C-integrating capacitor; GND-ground terminal; L-high voltage test branch; T-sample under test. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0019] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0020] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0021] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0022] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0023] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0024] The optional embodiments of this application are described in detail below with reference to the accompanying drawings.

[0025] The embodiment provided in this application is an embodiment of a low-voltage side acquisition system for insulating space charge under a positive polarity square wave. This system is capable of measuring the dynamic space charge characteristics inside an insulating material or structure under a positive polarity repetitive square wave voltage.

[0026] The embodiments of this application will be described in detail below with reference to Figure 1.

[0027] Figure 1 shows a schematic diagram of a low-voltage side acquisition system for insulating space charge under positive polarity square wave. As shown in Figure 1, the system includes a host computer 1, a signal generator 2, a voltage amplifier 3, a high-voltage electrode device 4, an optical fiber communication module 8, a signal acquisition unit 9, a current-limiting protection resistor R, a grounding terminal GND, and a high-voltage test branch L.

[0028] The host computer 1 acts as a control and data processing terminal, remotely configuring system parameters and processing received data.

[0029] Signal generator 2 generates a positive polarity repetitive square wave low-voltage signal with preset parameters.

[0030] Voltage amplifier 3 amplifies the low-voltage signal and outputs a positive polarity repetitive square wave high-voltage signal as a high-voltage test signal.

[0031] The current-limiting protection resistor R is connected to the output terminal of voltage amplifier 3 to limit the loop current.

[0032] The high-voltage test branch L includes the sample under test T and the integrating capacitor C, which are connected in series to the test circuit.

[0033] Fiber optic communication module 8 is used to realize optically isolated remote transmission of electrical signals.

[0034] Signal acquisition unit 9 is used to acquire and convert the voltage signal on the integrating capacitor C.

[0035] In this application, the system operates based on the current integration method. Specifically, the positive polarity repetitive square wave high-voltage signal output by voltage amplifier 3 is applied to the test sample T through a current-limiting protection resistor R. Since the test sample T is connected in series with the integrating capacitor C, the current flowing through them is the same, meaning the rate of change of charge with respect to time is the same. Therefore, the amount of charge accumulated on the integrating capacitor C dynamically reflects the dynamic amount of charge inside the test sample T. The signal acquisition unit 9 acquires the analog voltage signal across the integrating capacitor C. This voltage is related to the dynamic charge of the sample T being tested. Satisfying Relationship: Where C is the capacitance of the integrating capacitor C. This is achieved by measuring... This allows us to indirectly obtain the dynamic characteristics of the space charge of the tested sample T.

[0036] As one feasible embodiment, the components of the system are connected in the following manner to form a complete measurement loop.

[0037] For example, the output of signal generator 2 is connected to the input of voltage amplifier 3. Signal generator 2 is, for example, a programmable function generator used to generate a positive repetitive square wave signal with adjustable frequency and amplitude.

[0038] For example, the output of voltage amplifier 3 is connected to one end of the current-limiting protection resistor R. Voltage amplifier 3 is, for example, a high-voltage DC amplifier with adjustable amplification factor.

[0039] For example, the other end of the current-limiting protection resistor R is connected to the high-voltage test branch L.

[0040] For example, the high-voltage test branch L consists of the test sample T and the integrating capacitor C connected in series. The other end of the current-limiting protection resistor R is connected to the input terminal of the test sample T. The output terminal of the test sample T is connected to one end of the integrating capacitor C and the input terminal of the signal acquisition unit 9. The other end of the integrating capacitor C is connected to the ground terminal GND.

[0041] For example, the output of the signal acquisition unit 9 is connected to the input of the optical fiber communication module 8.

[0042] For example, the host computer 1 is connected to the signal generator 2, the voltage amplifier 3, and the fiber optic communication module 8. The host computer 1 is, for example, a computer with dedicated control software installed, connected via a communication cable (e.g., [example of a computer]). , (e.g., network cable, etc.) are connected to signal generator 2 and voltage amplifier 3, and connected to fiber optic communication module 8 through fiber optic cable, thereby realizing remote control and data reception.

[0043] In some embodiments, the high-voltage test branch L further includes a high-voltage electrode device 4 with a three-electrode structure, which consists of a counter electrode, a measuring electrode, and a protection electrode.

[0044] In some specific embodiments, the high-voltage electrode device 4 achieves uniform distribution of electric field and accurate extraction of charge signal by close physical stacking with the test sample T.

[0045] In one specific embodiment, the test sample T is placed in the central region inside the high-voltage electrode device 4 and is clamped from the upper and lower end faces by the counter electrode and the measuring electrode, forming a longitudinally arranged sandwich structure.

[0046] In this embodiment, the stacking position relationship ensures that the high voltage excitation output by the voltage amplifier 3 can act directly on the insulating medium through physical contact, while the weak space charge signal excited inside the test sample T can be transmitted to the acquisition circuit without loss through the contact interface.

[0047] In one specific embodiment, the counter electrode is connected to the output terminal of voltage amplifier 3 (in example, via a current-limiting protection resistor R) to apply high voltage to the test sample T. The measuring electrode is connected to one end of the integrating capacitor C to extract the current signal flowing through the sample. The protection electrode is directly connected to the ground terminal GND to eliminate interference from edge leakage current on the measurement and ensure that all current flowing through the measuring electrode flows through the integrating capacitor C.

[0048] For example, when the sample T being tested is a solid insulating film, a solid three-electrode structure made of metallic material can be used, with the sample sandwiched between the counter electrode and the measuring electrode (in the example, or the guard electrode). When the sample T being tested is a liquid or gel-like insulating material, a liquid three-electrode structure consisting of a container holding the liquid can be used.

[0049] For example, the materials of the counter electrode and the measuring electrode are non-ferromagnetic metallic materials, such as copper, aluminum, or stainless steel, to avoid introducing additional electromagnetic interference. The surface roughness of the counter electrode and the measuring electrode is less than [value missing]. The relative flatness is less than This ensures good contact with the sample and a uniform electric field distribution.

[0050] Silicon carbide (SiC) devices are typically used in high-voltage applications ranging from several kilovolts to tens of kilovolts, and their operating voltages are expected to increase further in the future. This poses a greater challenge to the insulation performance and reliability of the encapsulation insulation materials and structures used in SiC devices. Research indicates that space charge accumulation is a key factor limiting the insulation performance and reliability of power equipment. The accumulation of space charge directly alters the electric field distribution within the insulation structure, leading to partial discharge, accelerating insulation aging, lowering the breakdown threshold, and ultimately reducing the insulation performance of the power equipment. However, current research lacks sufficient information on the space charge accumulation characteristics of SiC device encapsulation insulation materials and structures under actual operating conditions—specifically, a positive polarity repetitive square wave voltage.

[0051] In this regard, the present application provides a low-voltage side acquisition system for insulating space charge under positive square wave, which can be developed and applied to the measurement of space charge accumulation characteristics of silicon carbide device packaging insulating materials and structures under positive repetitive square wave voltage.

[0052] In some embodiments, if the sample T under test is a silicon carbide device package insulation structure, the insulation structure itself already has leads for electrical connection (e.g., the gate, source, or specific test pins of the device). In this case, the leads at both ends of the insulation structure are connected to the integrating capacitor C and the current-limiting protection resistor R, respectively, without the need for the high-voltage electrode device 4. During measurement, the high-voltage signal is directly applied to the corresponding terminals of the insulation structure.

[0053] Figure 2 shows a schematic diagram of the test results of a certain silicon carbide device packaging insulating material.

[0054] In one specific embodiment, the space charge characteristics of a silicon carbide device packaging insulating material were tested using a data acquisition system, and the test results are shown in Figure 2.

[0055] For example, in Figure 2, the horizontal axis represents the test time, and the vertical axis represents the charge quantity. It can be observed that during the continuous application of a positive polarity repetitive square wave high voltage, due to the continuous injection and accumulation of charge within the dielectric, the total charge quantity inside the insulating material shows a significant upward trend over time. This directly reflects the dynamic accumulation process of space charge under actual working conditions. By observing the magnified view provided in the figure, it can be seen that because this system can successfully capture the high-frequency charge pulsation details that perfectly correspond to the square wave voltage frequency, this nanocoulomb-level precision acquisition capability proves that the system has excellent signal-to-noise ratio and time resolution, providing reliable data support for further calculations of the material's dielectric constant, dielectric relaxation time, and assessment of insulation degradation.

[0056] As a specific embodiment, the frequency of the positive polarity repetitive square wave output by signal generator 2 is: The amplitude of the square wave voltage can be Set within the range.

[0057] As one specific embodiment, voltage amplifier 3 has The adjustable amplification factor can amplify the input low-voltage square wave signal, with an output amplitude of [value missing]. to A positive polarity repetitive square wave high voltage signal; voltage amplifier 3 has a maximum load current of Its output capability.

[0058] As one specific embodiment, the resistance value of the current-limiting protection resistor R is set according to the maximum load current and the highest output voltage of the voltage amplifier 3. For example, when the output voltage is... The maximum load current is At that time, the resistance value of the current-limiting resistor should not be less than .

[0059] In a preferred embodiment, the resistance value of the current-limiting protection resistor R is... It is used to limit sudden short-circuit current under normal test conditions and protect voltage amplifier 3.

[0060] For example, the integrating capacitor C is a key component in the current integration method, and its performance directly affects the measurement accuracy. The integrating capacitor C is a leakage-free current capacitor made of polypropylene, polystyrene, or polytetrafluoroethylene film. These dielectric materials have extremely high insulation resistance and extremely low dielectric loss, which ensures that the leakage current of the capacitor itself is much smaller than the measured current during the measurement time, thereby guaranteeing the integration accuracy.

[0061] For example, the capacitance of the integrating capacitor C is equal to the capacitance of the sample T under test. The integral voltage can be reduced by selecting a larger integrating capacitor C. The amplitude is adjusted to be within the optimal measurement range of the signal acquisition unit 9, while simultaneously improving the signal-to-noise ratio.

[0062] For example, when the capacitance T of the tested sample is approximately several hundred picofarads, the value of the integrating capacitance C can be selected as follows: to When the sample has an insulating structure and the capacitance is smaller, the value of the integrating capacitance C can be reduced accordingly.

[0063] As a preferred configuration, the capacitance of the integrating capacitor C is [value missing]. It is suitable for testing a wide range of samples with a broad capacitance range.

[0064] For example, the signal acquisition unit 9 includes a voltage follower 5, an analog-to-digital converter 6, and a microcontroller 7 cascaded together.

[0065] The non-inverting input of the voltage follower 5 is connected between the integrating capacitor C and the sample T under test, and is used to directly sense the analog voltage signal on the integrating capacitor C. The inverting input of voltage follower 5 is connected to its output, forming a unity-gain negative feedback, so that its output voltage is equal to the input voltage (in the example shown). The voltage follower 5 has high input impedance and low output impedance, which allows it to buffer the voltage signal and drive the subsequent circuit without drawing a significant current from the integrating capacitor C, thus achieving good isolation from the preceding integrating circuit.

[0066] For example, the input of analog-to-digital converter 6 is connected to the output of voltage follower 5 to convert analog voltage signals. Convert to digital voltage signal The sampling rate, resolution, and other parameters of the analog-to-digital converter 6 can be configured by the microcontroller 7.

[0067] For example, one input / output port of the microcontroller 7 is connected to the digital output of the analog-to-digital converter 6 to receive digital voltage signals. The microcontroller 7, for example, is an ARM Cortex-M series chip, responsible for controlling the start and stop of the analog-to-digital converter 6, the sampling rate, and temporarily storing or preprocessing the acquired data.

[0068] For example, the signal acquisition unit 9 is integrated on the PCB board 10, and its circuit layout is optimized to reduce the impact of parasitic parameters and external electromagnetic interference on weak signals.

[0069] For example, the fiber optic communication module 8 is integrated on the PCB board 10. The receiving port of the fiber optic communication module 8 is electrically connected to the output and control ports of the microprocessor in the signal acquisition unit 9, respectively. The microprocessor acquires and processes the digital voltage signal. The signal is sent to fiber optic communication module 8. Fiber optic communication module 8 converts the electrical signal into an optical signal, which is then transmitted through the optical fiber. This design achieves complete electrical isolation between the measurement end (high-voltage side in this example) and the control processing end (low-voltage side in this example), effectively suppressing ground loop interference and potential threats from the high-voltage end to low-voltage equipment.

[0070] For example, the integrating capacitor C, the signal acquisition unit 9, and the fiber optic communication module 8 are all integrated on the same PCB board 10. This highly integrated design reduces the system size, simplifies external wiring, improves the system's mechanical stability and anti-interference capability, and enhances the convenience and reliability of measurement.

[0071] In some specific embodiments, the measurement process of the low-voltage side acquisition system for insulating space charge under positive polarity square wave includes the following steps S1 to S4.

[0072] Step S1: If the sample is an insulating material, install it in the high-voltage electrode device 4; if the sample is a silicon carbide device encapsulation insulating structure, connect the lead-out terminals at both ends of the sample directly to the circuit.

[0073] Step S1 ensures that the sample under test T and the integrating capacitor C are connected in series to form a high-voltage test branch L.

[0074] Step S2: The host computer 1 is used to remotely configure test parameters, specifically including: setting the output voltage amplitude and frequency of the signal generator 2 to generate the required positive polarity repetitive square wave low-voltage signal; setting the amplification factor of the voltage amplifier 3 to determine the final high voltage amplitude applied to the sample; and setting the sampling rate and acquisition duration of the analog-to-digital converter 6 in the signal acquisition unit 9.

[0075] For example, the sampling rate is set to more than 10 times the frequency of the applied square wave to ensure that the dynamic details of the charge can be captured; the single pressurization acquisition time is set to 3 minutes, and the sample can be short-circuited for 1 minute after pressurization to release residual charge. This cycle can be repeated multiple times.

[0076] Step S3: The host computer 1 sends a start command to the signal generator 2, voltage amplifier 3, and microcontroller 7; the system begins to apply a positive polarity repetitive square wave high voltage to the sample under test T, and at the same time, the signal acquisition unit 9 begins to synchronously acquire the voltage signal on the integrating capacitor C. and convert it into a digital signal. It is sent back to the host computer 1 via the fiber optic communication module 8.

[0077] Step S4: The host computer 1 processes the received data and displays the waveform in real time. Host computer 1 receives digital voltage signals. According to the formula The dynamic charge quantity was calculated. and draw A curve that changes over time; furthermore, it is possible to... The signal is analyzed to extract the characteristics of space charge accumulation and dissipation, or to calculate relevant parameters such as dielectric response.

[0078] The low-voltage side acquisition system for insulating space charge under positive polarity square wave provided in this application embodiment achieves accurate and safe measurement of the internal dynamic space charge characteristics of insulating materials or structures under positive polarity repetitive square wave voltage by adopting a system architecture including a signal generator 2, a voltage amplifier 3, a current limiting protection resistor R, a high-voltage test branch L composed of the test sample T and the integrating capacitor C connected in series, a signal acquisition unit 9 integrated on a PCB board 10, an optical fiber communication module 8 integrated on a PCB board 10, and a host computer 1.

[0079] The system provided in this application is based on the principle of current integration. It extracts the analog voltage signal reflecting the dynamic charge of the test sample T on the integrating capacitor C through the signal acquisition unit 9 and converts it into a digital signal. The digital voltage signal is then transmitted with electrical isolation through the fiber optic communication module 8, effectively solving the problems of electrical isolation and anti-interference between the high-voltage and low-voltage sides.

[0080] The system provided in this application features high integration and automation. Specifically, the integrating capacitor C, signal acquisition unit 9, and fiber optic communication module 8 are integrated on the same PCB board 10, resulting in a compact structure and high reliability. The host computer 1 is connected to the signal generator 2, voltage amplifier 3, and fiber optic communication module 8, respectively, enabling remote one-click configuration of test parameters, automatic control of the measurement process, and real-time processing and visualization of measurement data, significantly improving testing efficiency and intelligence.

[0081] Although the operations are described in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all of the operations shown to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0082] The system of this application can be implemented using standard programming techniques, utilizing rule-based logic or other logic to achieve various system steps. It should also be noted that the terms "device" and "module" as used herein and in the claims are intended to include implementations using one or more lines of software code and / or hardware implementations and / or devices for receiving input.

[0083] Any step, operation, or procedure described herein may be performed or implemented using one or more hardware or software modules, either alone or in combination with other devices. In one embodiment, the software module is implemented using a computer program product comprising a computer-readable medium containing computer program code, which is executable by a computer processor to perform any or all of the described steps, operations, or procedures.

[0084] The foregoing description of implementations of this application has been provided for illustrative and descriptive purposes. The foregoing description is not exhaustive and is not intended to limit this application to the exact forms disclosed. Various modifications and variations may exist in accordance with the foregoing teachings, or may arise from practice of this application. These embodiments were chosen and described to illustrate the principles of this application and its practical application, enabling those skilled in the art to utilize this application in various implementations and modifications to suit the specific purpose of the concept.

[0085] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments of the system, and will not be elaborated upon here.

[0086] It can be further understood that, unless otherwise specified, "connection" includes both direct connections where no other components exist between the two parties and indirect connections where other components exist between them.

[0087] It is further understood that although the operations are described in a specific order in the accompanying drawings in the embodiments of this application, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all the operations shown to be performed to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0088] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the field of this application that are not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0089] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

[0090] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A system for acquiring low-voltage side insulated space charge under positive polarity square wave, characterized in that, include: A signal generator is used to output a positive repetitive square wave low-voltage signal; a voltage amplifier, with its input connected to the signal generator, is used to amplify the low-voltage signal and output a positive repetitive square wave high-voltage signal; a current-limiting protection resistor is connected at one end to the output of the voltage amplifier; a high-voltage test branch is composed of the test sample and an integrating capacitor connected in series, with the other end of the current-limiting protection resistor connected to the input of the test sample, the output of the test sample connected to one end of the integrating capacitor and the input of the signal acquisition unit, and the other end of the integrating capacitor grounded; the signal acquisition unit, integrated on the PCB board, is used to extract the analog voltage signal reflecting the dynamic charge of the test sample on the integrating capacitor through a voltage follower, and convert the analog voltage signal into a digital voltage signal; an optical fiber communication module, integrated on the PCB board, is used to transmit the digital voltage signal with electrical isolation; a host computer, connected to the signal generator, the voltage amplifier, and the optical fiber communication module, is used to remotely configure test parameters and process the received data and display the waveform in real time.

2. The system according to claim 1, characterized in that, The high-voltage test branch also includes a high-voltage electrode device with a three-electrode structure, which consists of a counter electrode, a measuring electrode, and a protection electrode.

3. The system according to claim 2, characterized in that, The counter electrode is connected to the output terminal of the voltage amplifier, the measuring electrode is connected to one end of the integrating capacitor, and the protection electrode is directly grounded.

4. The system according to claim 2, characterized in that, The materials of the counter electrode and the measuring electrode are non-ferromagnetic metallic materials, and the surface roughness of the counter electrode and the measuring electrode is less than [value missing]. The relative flatness is less than 。 5. The system according to claim 2, characterized in that, If the sample under test is a silicon carbide device packaging insulation structure, the terminals at both ends of the insulation structure are connected to the integrating capacitor and the current limiting protection resistor respectively, and the high-voltage electrode device is not required.

6. The system according to claim 1, characterized in that, The frequency of the positive polarity repetitive square wave output by the signal generator is The resistance value of the current limiting protection resistor is 。 7. The system according to claim 1, characterized in that, The maximum load current of the voltage amplifier is The amplification factor of the voltage amplifier is... Adjustable between multiples.

8. The system according to claim 1, characterized in that, The integrating capacitor is a leakage-free current capacitor made of polypropylene, polystyrene, or polytetrafluoroethylene film, and the capacitance value of the integrating capacitor is the capacitance value of the sample under test. Double.

9. The system according to claim 1, characterized in that, The signal acquisition unit includes a voltage follower, an analog-to-digital converter, and a microcontroller cascaded together; wherein, the non-inverting input of the voltage follower is connected between the integrating capacitor and the sample under test, and the inverting input of the voltage follower is connected to the output of the voltage follower.

10. The system according to claim 1, characterized in that, The integrating capacitor, the signal acquisition unit, and the optical fiber communication module are all integrated on the same PCB board. The receiving port of the optical fiber communication module is electrically connected to the output terminal and control port of the microprocessor in the signal acquisition unit, respectively.

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