A method for monitoring the health state of a grid-connected energy storage detection platform and related devices

Abstract

The present application belongs to the technical field of energy storage, and discloses a kind of energy storage grid-connected detection platform health state monitoring method and related device.The present application aims to solve the technical problems of incomplete health state monitoring and inaccurate evaluation of existing energy storage grid-connected detection platform.The technical scheme of the present application judges the fault of energy storage grid-connected detection platform by stages: first, complete a fault judgment based on the filtered three-phase current on the output side, if the current is abnormal, further secondary fault judgment is carried out based on the three-phase voltage before filtering on the output side;if the three-phase voltage before filtering is normal, the state of the filter capacitor is detected;if the three-phase voltage before filtering is missing, the state of the insulated gate bipolar transistor (IGBT) is detected.The present application can comprehensively monitor the two core devices of IGBT and filter capacitor, and can more completely and accurately evaluate the overall health status of energy storage grid-connected detection platform, providing key technical support for ensuring the reliable operation of energy storage system.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, and specifically relates to a method and related device for monitoring the health status of an energy storage grid-connected testing platform. Background Technology

[0002] Energy storage technology is a key technology for solving the problems of volatility and intermittency in new energy power generation. The energy storage grid connection testing platform is used to test key indicators of energy storage systems, such as power control, fault ride-through capability, and power quality, to ensure reliable operation under grid fluctuations and faults, and to avoid grid outages or stability problems caused by energy storage device failures.

[0003] Most existing energy storage grid-connected testing platforms are built based on power electronics technology, employing modular cascaded multi-level topologies for direct grid connection. This allows for flexible adjustment of output voltage and frequency, thereby improving the accuracy of grid simulation. However, as the number of cascaded levels increases, the health of the energy storage grid-connected testing platform is affected. Specifically, with the increase in the number of cascaded levels, the number of power switching devices included in the platform increases exponentially, leading to a higher probability of failure. Furthermore, considering that the energy storage grid-connected testing platform needs to simulate the harsh operating environment of the power grid, coupled with its long-term uninterrupted operation and susceptibility to electromagnetic interference, the probability of failure is further exacerbated.

[0004] Insulated-gate bipolar transistors (IGBTs) and filter capacitors are subjected to high-frequency harmonics or high-frequency switching over long periods, resulting in significant internal performance aging. These components have become critical to the health and reliability of the entire energy storage grid-connected testing platform. For example, statistics show that nearly 50% of the health status of energy storage grid-connected testing platforms is related to these two components. Further, in the actual operation of the platform, the IGBT, as the control core, endures harsh conditions such as high-frequency switching, high-current surges, and severe thermal cycling, making it highly susceptible to aging failures such as bond wire detachment and solder fatigue. Filter capacitors, subjected to long-term high-frequency harmonics, experience severe performance degradation, significantly reducing filtering effectiveness and deteriorating power quality. In severe cases, this can lead to overheating, bulging, or even explosion of the capacitor, threatening the health of the platform and potentially triggering shutdowns or fires. This not only results in inaccurate grid-connected testing of the energy storage system but also directly threatens the reliability of the system's operation.

[0005] Currently, research on health status monitoring of energy storage grid-connected testing platforms mainly focuses on IGBT performance, including direct online monitoring based on saturation voltage drop, indirect monitoring based on thermistor parameters, and drive circuit signal analysis. Direct online monitoring based on saturation voltage drop relies on the IGBT output characteristic curve. A specific current value is injected during shutdown, and the aging state of the IGBT is determined by collecting the corresponding saturation voltage drop data. Its main drawback is the complexity of the operation process, and it can only be performed when the energy storage grid-connected testing platform is shut down. Indirect monitoring based on thermistor parameters uses threshold voltage changes as the monitoring indicator, requiring accurate identification of the IGBT current rising edge and the establishment of complex thermal models and decoupling algorithms. Its main drawback is the difficulty of online implementation. Drive circuit signal analysis diagnoses by monitoring changes in the gate drive waveform, using the gate voltage overshoot during IGBT turn-on as the monitoring parameter. Its main drawback is that the gate voltage overshoot value is closely related to the drive circuit connection method; improper drive circuit design will lead to inaccurate monitoring. In summary, all the existing monitoring solutions mentioned above have certain problems and are mainly implemented for IGBTs, with little attention paid to filter capacitors. They cannot fully assess the health status of the energy storage grid-connected testing platform. There is an urgent need to develop a health status monitoring solution for energy storage grid-connected testing platforms that comprehensively considers the performance of both IGBTs and filter capacitors. Summary of the Invention

[0006] The purpose of this invention is to provide a method and related apparatus for monitoring the health status of an energy storage grid-connected testing platform, thereby solving one or more of the aforementioned technical problems. The technical solution disclosed in this invention can comprehensively monitor two core components, IGBTs and filter capacitors, enabling a more complete and accurate assessment of the overall health status of the energy storage grid-connected testing platform, and thus providing key technical support for ensuring the reliable operation of the energy storage system.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for monitoring the health status of an energy storage grid-connected testing platform, comprising the following steps: Step 1: Perform a fault judgment based on the three-phase current after filtering on the output side of the energy storage grid-connected detection platform. If the three-phase current after filtering on the output side is normal, output the healthy status monitoring result and end the monitoring process. If the three-phase current after filtering on the output side is abnormal, proceed to step 2. Step 2: Perform secondary fault judgment based on the output-side three-phase voltage before filtering of the energy storage grid-connected testing platform: If the output-side three-phase voltage before filtering is normal, perform filter capacitor status detection and output the health status monitoring result of the energy storage grid-connected testing platform according to the detection result; If the output-side three-phase voltage before filtering has missing levels, perform insulated gate bipolar transistor (IGBT) status detection and output the health status monitoring result of the energy storage grid-connected testing platform according to the detection result.

[0008] A further improvement to the technical solution of this invention is that, in the step of detecting the status of the filter capacitor and outputting the health status monitoring result of the energy storage grid-connected testing platform based on the detection result if the three-phase voltage before the output side filter is normal, the filter capacitor status detection step at the selected monitoring time point includes: The noise-reduced capacitor branch current and the voltage across the capacitor are substituted into the equivalent model of the filter capacitor. The actual equivalent parameters of the filter capacitor corresponding to the selected monitoring time point are obtained through the parameter identification algorithm. The actual equivalent parameters of the filter capacitor are compared with the capacitor reference parameters to obtain the parameter deviation value. Based on the actual equivalent parameters of the filter capacitor and the parameter deviation value, the voltage differential error value is derived and calculated using the voltage differential error propagation mechanism. The parameter deviation value is compared with the preset threshold range of parameter deviation, and the voltage differential error value is compared with the preset threshold range of voltage differential error. Based on the comparison result, the filter capacitor status detection result at the selected monitoring time point is output.

[0009] A further improvement of the technical solution of the present invention is that, in the step of comparing the parameter deviation value with the preset threshold range of parameter deviation, comparing the voltage differential error value with the preset threshold range of voltage differential error, and outputting the filter capacitor status detection result at the selected monitoring time point based on the comparison result, if the parameter deviation value is within the preset threshold range of parameter deviation and the voltage differential error value is within the preset threshold range of voltage differential error, then the filter capacitor status detection result is normal; otherwise, the filter capacitor status detection result is deteriorated.

[0010] A further improvement of the technical solution of the present invention is that, in the step of detecting the status of the filter capacitor and outputting the health status monitoring result of the energy storage grid-connected detection platform according to the detection result, if the three-phase voltage before the output side filter is normal, multiple monitoring time points are set according to the preset time monitoring interval when detecting the status of the filter capacitor.

[0011] A further improvement to the technical solution of this invention is that, in the step of performing IGBT state detection and outputting the health status monitoring result of the energy storage grid-connected testing platform based on the detection result if the three-phase voltage before output filtering is missing a certain level, the step of performing IGBT state detection includes: Obtain the overall transient loss data of the three phases of the IGBT; Based on the overall transient loss data of IGBT three phases, the current-power ripple spectrum is introduced as an aging characteristic quantity. The characteristic parameters strongly correlated with IGBT aging are extracted by fast Fourier transform to obtain the aging characteristic parameters. The aging type is identified and the aging device is located based on the aging characteristic parameters, and the IGBT status detection result is output based on the identification and location results.

[0012] A further improvement to the technical solution of this invention lies in that the step of obtaining the overall transient loss data of the three phases of the IGBT includes: Collect operating parameters; wherein, the operating parameters include: the on-current, voltage, and temperature of the IGBT three-phase bridge arm, as well as the platform switching frequency and pulse width modulation timing parameters; The collected operating parameters are input into a pre-constructed three-phase overall transient loss model, which calculates and outputs the original IGBT three-phase overall transient loss data. The original IGBT three-phase overall transient loss data is denoised and filtered to remove interference components, and the final IGBT three-phase overall transient loss data is obtained. The construction steps of the three-phase overall transient loss model include: collecting IGBT single-phase operating data and establishing a conduction characteristic model; based on the conduction characteristic model, combining the calculation principles of IGBT conduction loss and switching loss, incorporating the switching frequency and pulse width modulation timing parameters of the energy storage grid-connected detection platform, and establishing a single-phase positive half-wave transient loss model applicable only to the single-phase positive half-wave interval of IGBT; based on the single-phase positive half-wave transient loss model and the symmetrical operating characteristics of the three-phase circuit, deriving the transient loss components of the second and third phases respectively through phase mapping; integrating and verifying the single-phase positive half-wave transient loss model and the transient loss components of the second and third phases to form a three-phase overall transient loss model that can completely characterize the power loss variation law of the three-phase bridge arm of IGBT during the entire conduction and switching process.

[0013] A further improvement to the technical solution of this invention lies in the following steps: identifying the aging type and locating the aging device based on aging characteristic parameters, and outputting the IGBT state detection result based on the identification and location result, including: The aging characteristic parameters are compared with the standard data in the IGBT manual, or compared with the preset aging threshold to determine whether the aging characteristic parameters exceed the normal range. If they do not exceed the normal range, the IGBT status detection result is normal. If they exceed the normal range, the aging mode of the IGBT and the location of the aging device are identified by combining the differences in the spectral characteristics corresponding to different aging combinations of single, dual, and triple transistors.

[0014] In a second aspect, the present invention provides a health status monitoring system for an energy storage grid-connected testing platform, comprising: a primary fault judgment unit and a secondary fault judgment unit; wherein, The primary fault judgment unit is used to perform a primary fault judgment based on the output-side filtered three-phase current of the energy storage grid-connected detection platform: if the output-side filtered three-phase current is normal, the healthy status monitoring result is output and the monitoring process ends; if the output-side filtered three-phase current is abnormal, the process jumps to execute the steps of the secondary fault judgment unit. The secondary fault judgment unit is used to perform secondary fault judgment based on the output side filtering three-phase voltage of the energy storage grid-connected detection platform: if the output side filtering three-phase voltage is normal, the filter capacitor status is detected and the health status monitoring result of the energy storage grid-connected detection platform is output according to the detection result; if the output side filtering three-phase voltage has a missing level, the insulated gate bipolar transistor (IGBT) status is detected and the health status monitoring result of the energy storage grid-connected detection platform is output according to the detection result.

[0015] In a third aspect, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the energy storage grid-connected testing platform health status monitoring method as described in any one of the first aspects of the present invention.

[0016] In a fourth aspect, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the energy storage grid-connected detection platform health status monitoring method as described in any one of the first aspects of the present invention.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a health status monitoring scheme for an energy storage grid-connected testing platform. It comprehensively monitors two core components: IGBTs and filter capacitors, avoiding the risk of missed fault detection inherent in existing single IGBT monitoring. This allows for a more complete and accurate assessment of the overall health status of the energy storage grid-connected testing platform. Specifically, addressing the problem of incomplete platform health assessments due to existing technologies focusing only on IGBTs and neglecting filter capacitors, this invention uses a two-step fault diagnosis approach—first current, then voltage—to clearly define the fault investigation scope as either IGBTs or filter capacitors. This achieves complete coverage of both core components, avoiding the risk of missed fault detection associated with single IGBT monitoring. Furthermore, addressing the issue of high maintenance costs due to the lack of effective means for quickly locating faulty components in existing technologies, this invention uses a progressive analysis of the three-phase current after filtering and the three-phase voltage before filtering on the output side. This allows for rapid identification of the root cause of the fault as either the IGBT or the filter capacitor, clearly defining the scope for subsequent specialized monitoring and significantly improving the efficiency and accuracy of fault diagnosis. Furthermore, existing monitoring methods often require shutdown or disassembly of equipment, which cannot meet the long-term uninterrupted operation requirements of the platform. The technical solution of this invention directly utilizes the output-side voltage and current sensors of the energy storage grid-connected detection platform to monitor data. It can complete the initial fault judgment without additional hardware modification or shutdown, and can realize online and real-time health status monitoring, which can provide effective technical support for ensuring the reliable operation of the energy storage system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating a method for monitoring the health status of an energy storage grid-connected testing platform, as described in Embodiment 1 of the present invention.

[0020] Figure 2 This is a flowchart illustrating a method for monitoring the health status of an energy storage grid-connected testing platform, as described in Embodiment 4 of the present invention.

[0021] Figure 3 This is a schematic diagram of a health status monitoring system for an energy storage grid connection detection platform in Embodiment 5 of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention; obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] Based on the technical solutions disclosed in the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0024] Example 1 Please see Figure 1 The present invention provides a method for monitoring the health status of an energy storage grid-connected testing platform, which specifically includes the following steps: Step 1: Perform a fault judgment based on the three-phase current after filtering on the output side of the energy storage grid-connected detection platform. If the three-phase current after filtering on the output side is normal, output a healthy status monitoring result and end the monitoring process. If the three-phase current after filtering on the output side is abnormal, proceed to step 2.

[0025] For illustrative purposes, in this step, the conditions for the normal operation of the three-phase current after output filtering may include: balanced three-phase current amplitudes, with each phase current being basically the same size and without significant deviations in magnitude; complete, continuous, and smooth current waveforms without abrupt changes, spikes, discontinuities, or distortions; current frequency, amplitude, and effective value all falling within the preset normal operating range of the energy storage grid-connected testing platform; and absence of abnormal characteristics such as overcurrent, phase loss, discontinuity, and harmonic distortion.

[0026] Step 2: Perform secondary fault judgment based on the three-phase voltage before filtering on the output side of the energy storage grid-connected testing platform. If the three-phase voltage before filtering on the output side is normal, perform filter capacitor status detection and output the health status monitoring result of the energy storage grid-connected testing platform based on the detection result. If the three-phase voltage before filtering on the output side has missing levels, perform insulated gate bipolar transistor (IGBT) status detection and output the health status monitoring result of the energy storage grid-connected testing platform based on the detection result.

[0027] For illustrative purposes, in this step, the conditions for the normal operation of the three-phase voltage before output filtering may include: the waveform of the three-phase voltage before output filtering is complete, the number of voltage levels is complete, the three phases are balanced, the voltage amplitude, frequency, and phase are all within the preset normal operating range, there is no missing voltage level, no waveform distortion, no phase loss, no jump, no obvious harmonic distortion, and it conforms to the PWM (Pulse Width Modulation) output voltage characteristics when the energy storage grid-connected testing platform is operating normally.

[0028] This invention discloses a novel health status monitoring method for an energy storage grid-connected testing platform. This method offers more comprehensive and accurate health status assessment, faster and more precise fault location, and significantly improved engineering practicality and economy. Specifically, the technical solution of this invention, by comprehensively monitoring two core components—IGBTs and filter capacitors—avoids the limitations of monitoring only IGBTs. It can completely and accurately reflect the overall health status of the energy storage grid-connected testing platform, effectively preventing safety accidents caused by filter capacitor failure. The technical solution of this invention employs a clear two-step fault judgment logic, quickly pinpointing the fault source to either the IGBT or the filter capacitor, avoiding blind troubleshooting and significantly improving the efficiency and accuracy of fault diagnosis, providing a clear direction for subsequent preventative maintenance. This technical solution of this invention relies on existing sensor data from the energy storage grid-connected testing platform, without requiring damage to device packaging or shutdown, reducing the economic cost and operational complexity of monitoring. It is adaptable to the long-term, uninterrupted operation requirements of the energy storage grid-connected testing platform and has extremely high engineering promotion value.

[0029] Example 2 In the specific exemplary technical solutions of this invention, based on the technical solution disclosed in Embodiment 1, the specific steps for detecting the state of the filter capacitor, including the process of detecting the state of the filter capacitor at the selected monitoring time point, are as follows: Step 1: Substitute the noise-reduced capacitor branch current and the voltage across the capacitor into the equivalent model of the filter capacitor. Obtain the actual equivalent parameters of the filter capacitor corresponding to the selected monitoring time point through a preset parameter identification algorithm (interpretably, these may include the actual capacitance value and the actual equivalent series resistance value). Compare and calculate the obtained actual equivalent parameters of the filter capacitor with the pre-calibrated offline capacitor reference parameters (interpretably, these may include the reference capacitance value and the reference equivalent series resistance value) to obtain the parameter deviation value (interpretably, the difference between the actual value and the reference value).

[0030] In a further specific and exemplary technical solution, the capacitor branch current in this step can be calculated by the difference between the current on the detection platform side and the current on the grid side. The current on the detection platform side, the current on the grid side, and the voltage across the capacitor can all be acquired by sensors.

[0031] In a further specific and exemplary technical solution, the construction of the equivalent model of the filter capacitor in this step may include the following process: based on the electrical characteristics of the filter capacitor, a general equivalent model of the capacitor is constructed (interpretably, it may include a series / parallel model of capacitance and equivalent resistance); then, using the measured voltage and current data from the data acquisition stage, the model is optimized by fitting algorithms such as least squares method or neural network algorithm to obtain an accurate volt-ampere characteristic characterization that reflects the actual electrical characteristics of the filter capacitor.

[0032] In a further specific and exemplary technical solution, the offline calibration of the capacitor reference parameters in this step may include the following process: obtaining the inherent reference parameters of the filter capacitor through offline testing, mainly including the reference capacitance value and the reference equivalent series resistance value, and calibrating the voltage and current threshold ranges under normal operating conditions of the capacitor; the offline calibration can provide a basic reference benchmark, and all subsequent parameter deviations and error calculations are based on the comparison of the offline calibration value.

[0033] Step 2: Based on the actual equivalent parameters and parameter deviations of the filter capacitor, the voltage differential error value (i.e., the dynamic error between the actual voltage response of the capacitor and the theoretically calculated voltage of the model) is derived and calculated using the voltage differential error propagation mechanism, completing the parameter-error mapping calculation at a single time point. Explained, this step, based on the equivalent model of the filter capacitor, introduces the voltage differential error propagation mechanism to derive the mathematical relationship between the deviation of capacitor parameters (capacitance value, equivalent resistance value) and the capacitor voltage response error, thus achieving a quantitative mapping of "capacitor parameter deviation → voltage differential error".

[0034] Step 3: Compare the parameter deviation value with the preset threshold range of parameter deviation, compare the voltage differential error value with the preset threshold range of voltage differential error, and output the filter capacitor status detection result at the selected monitoring time point based on the comparison result.

[0035] In a further specific and exemplary technical solution, the health level in the filter capacitor status detection result may specifically include: normal (parameter deviation value is within the threshold range and voltage differential error value is within the threshold range) and deteriorated (parameter deviation value is not within the threshold range or voltage differential error value is not within the threshold range).

[0036] In a further preferred technical solution, step 4 may also be included: repeating steps 1 to 3 above at a preset time monitoring interval (e.g., 50ms / 100ms, set according to the working conditions of the detection platform) to continuously collect real-time basic data of the filter capacitor at N time points (N≥3, to ensure the effectiveness of dynamic analysis), and sequentially completing parameter identification, parameter deviation calculation, voltage differential error calculation and detection result output at each time point.

[0037] In the technical solution disclosed in this invention, the first dimension is the deviation of the equivalent model parameters of the filter capacitor (the deviation between the reference value and the actual value of the capacitance value and the equivalent resistance value), the second dimension is the voltage differential error (the voltage dynamic error value calculated by the error propagation model from the parameter deviation), and the third dimension is the time dimension monitoring node (a continuous sequence of multiple time points). This realizes the upgrade from "single-dimensional static analysis" to "three-dimensional dynamic coupling", which can accurately assess the health status of the filter capacitor.

[0038] Example 3 In a specific exemplary technical solution of this invention, based on the technical solution disclosed in Embodiment 1, the specific detection process for the insulated gate bipolar transistor (IGBT) state detection step is as follows: Step 1: Obtain the transient loss data of the entire three-phase IGBT; Step 2: Based on the transient loss data obtained in Step 1, the current-power ripple spectrum is introduced as an aging characteristic quantity. The characteristic parameters strongly correlated with IGBT aging are extracted by fast Fourier transform to obtain the aging characteristic parameters, which may include the ripple amplitude at a specific frequency, the spectral energy distribution, etc. Step 3: Identify the aging type and locate the aging device based on the aging characteristic parameters obtained in Step 2, and output the IGBT status detection result based on the identification and location results.

[0039] In a further specific and exemplary technical solution, the specific process of obtaining the transient loss data of the IGBT three-phase system in step 1 is as follows: The platform uses its built-in sensors to collect real-time data on the conduction current, voltage, temperature of the IGBT three-phase bridge arm, as well as operating parameters such as platform switching frequency and PWM timing. The real-time collected operating parameters are input into the pre-built three-phase overall transient loss model. The three-phase overall transient loss model automatically calculates the real-time transient loss data of the IGBT three-phase system based on the built-in conduction characteristics, single-phase loss calculation rules and three-phase symmetry mapping relationship. The calculated real-time transient loss data is denoised and filtered to remove interference components such as electromagnetic interference and sampling noise, resulting in smooth and reliable loss time series data. This data serves as the final transient loss data for the three phases of the IGBT, providing a high-quality data foundation for subsequent feature extraction.

[0040] In a further specific and exemplary technical solution, the specific construction process of the three-phase overall transient loss model is as follows: Step (1): Collect single-phase operation data of IGBT and establish a conduction characteristic model.

[0041] In this step, the measured electrical parameters of the IGBT, such as conduction current, voltage, and temperature, can be collected based on the inherent sensors of the energy storage grid-connected testing platform within the single-phase positive half-wave range. The measured data are then fitted using the least squares method or polynomial fitting algorithm to establish an IGBT conduction characteristic model. This model quantifies the functional relationship between conduction resistance and current and temperature, providing a basis for device characteristic calculations.

[0042] Step (2): Construct a single-phase positive half-wave transient loss model for IGBTs.

[0043] In this step, based on the IGBT conduction characteristic model obtained in step (1), and combined with the calculation principle of IGBT conduction loss and switching loss, and taking into account the operating parameters such as the switching frequency and PWM timing of the detection platform, a transient loss model that is only applicable to the positive half-wave interval of IGBT is established to calculate the real-time transient loss of the phase in the positive half-wave operating interval.

[0044] Step (3): Based on the three-phase symmetrical mapping relationship, derive the loss components of the other two phases.

[0045] In this step, based on the symmetrical operation characteristics of the three-phase circuit, the transient loss components of the second and third phases are derived by phase mapping of the single-phase positive half-wave transient loss model established in step (2), so that the model covers all three-phase bridge arms.

[0046] Step (4): Integrate the three-phase loss components to form a three-phase overall transient loss model.

[0047] In this step, the single-phase positive half-wave transient loss model obtained in step (2) is integrated with the other two phase loss components derived in step (3) to form a three-phase overall transient loss model that can fully characterize the power loss change law of all three phase arms of IGBT during the entire process of conduction and switching.

[0048] In a further optional technical solution, after step (4), the following step is also included: step (5), which involves substituting standard data to verify and determine the final model.

[0049] In this step, standard parameters from the IGBT device manual and offline calibration loss data are substituted into the model for verification. The parameters of the three-phase overall transient loss model are corrected and optimized to ensure that the calculation accuracy meets the requirements of online monitoring. Finally, a usable three-phase overall transient loss model is determined. The three-phase overall transient loss model is a comprehensive analytical model that can completely characterize the transient changes in power loss of the three-phase bridge arms of the IGBT during the entire conduction and switching process. In this embodiment of the invention, bidirectional cross-validation and various accurate models are constructed to effectively remove noise interference, improve the accuracy and reliability of monitoring results, ensure accurate and efficient simulation by the testing platform, and provide technical support for the reliable operation of energy storage systems.

[0050] In a further specific and exemplary technical solution, the process of identifying the aging type and locating the aging device based on the aging characteristic parameters obtained in step 2, and outputting the IGBT status detection result based on the identification and location result includes: comparing the aging characteristic parameters obtained in step 2 with the standard data in the IGBT manual or with the preset aging threshold to determine whether the characteristic parameters exceed the normal range; based on the abnormality of the characteristic parameters, combined with the spectral characteristic differences corresponding to different aging combinations of single-tube, dual-tube, and triple-tube, identifying the IGBT aging mode, and locating the aging device of the specific phase and specific bridge arm.

[0051] In some embodiments, the power device aging combination classification is mainly divided into single-tube aging, dual-tube aging, and triple-tube aging. Single-tube aging focuses on the independent impact of the aging of a single IGBT power device; dual-tube aging studies the coupling effect of two power devices aging under symmetrical or asymmetrical conditions; triple-tube aging explores the nonlinear loss characteristics of the aging of three power devices as a group.

[0052] In some embodiments, single-tube aging mainly analyzes the fundamental frequency of 50Hz, using the 50Hz component as the fundamental harmonic of the pulse characteristics. Aging is mainly located in the upper or lower bridge arm. For dual-tube aging, the main harmonic component shifts to 100Hz, and the power ripple waveform under the superposition of the fundamental frequency and second harmonics is mainly analyzed. The location of aging may be in-phase dual-tubes, dual-tubes on the same side but different phases, or dual-tubes on opposite sides but different phases. Three-tube aging mainly occurs in three-tubes on the same side, two-phase three-tubes on opposite sides, and three-phase three-tubes on opposite sides. The power ripple of the three-tubes on the same side shows a significant concentration at 150Hz. The two-phase three-tubes on opposite sides have 100Hz as the dominant loss harmonic. The three-phase three-tubes on opposite sides are aged simultaneously by the three bridge arms, still using the 50Hz component as the fundamental harmonic component of the pulse characteristics.

[0053] This invention provides a real-time monitoring method for the health status of an energy storage grid-connected testing platform. It eliminates the need for device packaging or shutdown, fully utilizing the inherent current and voltage sensors and sampling data of the platform's control system to monitor the overall platform's health status in real time, enabling health status assessment. Specifically, it rapidly removes noise interference using least squares and fast Fourier transform, identifying key devices causing voltage and current fault waveforms. Combining the phase information of three-phase current and voltage, it achieves effective mapping and rapid location of aging characteristics. By analyzing the power loss ripple variation and its relationship with the three-phase current phase, a precise aging location model is established, effectively identifying the specific location of aging devices and indicating the overall health status of the platform, providing clear guidance for equipment maintenance. This invention also constructs a two-way cross-validation mechanism between simulated waveform data and device manual parameters. By comparing simulation results with theoretical device parameters, the accuracy and reliability of the monitoring results are ensured, providing solid data support for subsequent fault diagnosis.

[0054] Example 4 Please see Figure 2 The present invention provides a method for monitoring the health status of an energy storage grid-connected testing platform, comprising the following steps: First, data acquisition is performed, mainly including the input voltage and current, and the output current and voltage of the grid-connected testing platform.

[0055] Fault diagnosis is performed based on measured data of voltage and current. The main focus is on judging the three-phase voltage before filtering and the three-phase current after filtering. If the three-phase current after filtering is normal, the detection platform is healthy and normal. If the three-phase current after filtering is abnormal, observe the three-phase voltage before filtering. If it is normal, focus on checking the filter capacitor. If the voltage level is missing, focus on monitoring the IGBT status.

[0056] For IGBT status monitoring, the main considerations are the effects of switching frequency, PWM timing module, etc. A transient loss model of a single phase of the IGBT device in the positive half-wave interval is constructed. Through symmetrical mapping relationship, the power loss components of the other two phases are obtained, and finally a three-phase overall transient loss model is formed.

[0057] For the detection of filter capacitor status, the capacitor branch current is obtained by subtracting the current on the detection platform side and the grid side current. The noise contained in the capacitor current is calculated. After removing the noise interference, the capacitor parameters are identified, the voltage error transmission parameters are compared, the errors of the identified parameters are analyzed, and a three-dimensional dynamic error model is formed to realize the health status assessment of the filter capacitor.

[0058] This invention comprehensively considers the health status of key components, separately assesses IGBTs and filter capacitors, compares the dynamic model calculation results with offline calibrated benchmark parameter values, and performs coupled analysis. For IGBTs, a current-power ripple spectrum is introduced as an aging state characteristic quantity, and for filter capacitors, a voltage differential error propagation mechanism is introduced. Then, aging characteristic parameters are extracted to locate specific aging components and implement the health status monitoring and detection platform.

[0059] In a specific exemplary technical solution of this invention, the data acquisition process may include: accurately acquiring key electrical parameters of the testing platform during actual operation, providing a reliable data foundation for subsequent model building and aging state analysis; wherein, a high-precision current sensor is used to measure the current value of the IGBT in the conducting state in real time. This parameter directly reflects the load condition of the IGBT and is crucial for calculating conduction losses. Voltage and current sensors are installed on the input side of the grid-connected testing platform to measure the voltage and current signals input to the power grid. Input-side parameters help analyze the current in the filter capacitor branch and the impact of power grid fluctuations on key components. Voltage and current sensors are also set on the output side of the grid-connected testing platform to acquire the voltage and current data output to the device under test. Output-side parameters can reflect the current and voltage fault waveforms of the testing platform and determine the health status of the testing platform.

[0060] In a further specific and exemplary technical solution, a high-precision, high-bandwidth sensor can be selected to ensure accurate capture of rapidly changing electrical signals. The acquisition frequency is set according to the IGBT switching frequency and the dynamic characteristics of the detection platform, generally not less than 10 times the switching frequency, to ensure data integrity and accuracy. The data acquisition system should have real-time storage and transmission capabilities to promptly transmit the acquired data to the subsequent processing unit.

[0061] In a specific exemplary technical solution of this invention, the IGBT health status monitoring steps include: based on measured data, using advanced data fitting algorithms, such as least squares method and polynomial fitting, to accurately model the conduction characteristics of the IGBT. The mathematical model obtained through fitting can more accurately describe the relationship between the IGBT's on-resistance and factors such as current and temperature. The dynamic model calculation results are compared with offline calibrated loss values ​​using a lookup table method, including: processing the IGBT loss data calculated by the dynamic model through noise reduction filtering to remove noise interference and improve the accuracy and reliability of the data. By analyzing the frequency, amplitude, and other characteristics of the ripple, its intrinsic relationship with the device's aging degree can be discovered. The current-power ripple spectrum is introduced as an aging state characteristic quantity. Based on Fast Fourier Transform, aging characteristic parameters are extracted to identify feature parameters closely related to the IGBT's aging state, such as ripple amplitude and spectral energy distribution at specific frequencies. Based on the extracted aging characteristic parameters and a pre-set aging threshold, the specific aging device is located. When the aging characteristic parameter of a certain IGBT exceeds the set threshold, the device is determined to be an aging device, and corresponding warning information is given.

[0062] The technical solution of this invention can monitor the health status of the testing platform in real time. By continuously collecting and analyzing the electrical parameters and aging characteristic parameters of IGBTs, the overall health level of the system can be dynamically assessed. Subsequently, based on the health status assessment results, timely maintenance measures can be taken, such as replacing aging components and adjusting system operating parameters, to ensure the reliable operation of the system.

[0063] In a specific exemplary technical solution of this invention, the steps for monitoring the health status of the filter capacitor include: based on measured data, using advanced data fitting algorithms, such as least squares method and neural network algorithms, to accurately model the dynamic characteristics of the filter capacitor and obtain the current-voltage characteristic characterization of the filter capacitor. The parameters identified by the model are compared with the actual collected current and voltage data to calculate the voltage dynamic error, construct a differential error propagation model between the capacitor voltage and capacitor parameters, compare the collected data at multiple time points with the model calculation results, and analyze the deviation range by comparing resistance and capacitance errors to obtain the health status of the filter capacitor.

[0064] In summary, this invention provides a health status monitoring method for an energy storage grid-connected testing platform. It comprehensively monitors two core components: IGBTs and filter capacitors, enabling a complete and accurate assessment of the overall health status of the platform and avoiding the risk of missed fault detection inherent in existing single IGBT monitoring methods. This invention's technical solution allows for real-time and accurate monitoring and health assessment of the energy storage grid-connected testing platform during operation, effectively ensuring accurate and efficient simulation and providing crucial technical support for ensuring the reliable operation of energy storage systems.

[0065] Specifically, the technical solution disclosed in this invention, without damaging the device packaging or shutting down the system, utilizes the inherent current and voltage sensors and sampling data of the energy storage grid-connected monitoring platform to control the system. By judging the waveform characteristics of voltage and current, it identifies the relevant characteristics of fault waveforms, analyzes their correlation with IGBTs and filter capacitors, and obtains monitoring results. For IGBTs, the focus is on the transient power loss characteristics during their conduction and switching processes. By establishing a mapping model between power loss and IGBT aging status, and simultaneously comparing it with standard data from the IGBT technical manual, accurate verification of the IGBT aging status is achieved. For filter capacitors, by comparing offline calibrated capacitor reference parameters with the parameters of the actual capacitor equivalent model, parameter evaluation based on voltage error propagation is conducted, establishing a mapping relationship between parameter error and voltage response, and achieving quantitative evaluation of filter capacitor performance. In this invention, the ripple characteristics of IGBT transient power loss are identified through Fast Fourier Transform to pinpoint the characteristic frequency range of energy concentration outside the DC component, and combined with the phase information of the three-phase current, effective mapping and location of aging indicators are achieved. In this invention, the parameters of the filter capacitor adopt common volt-ampere characteristic parameters. By comparing the offline calibrated capacitor reference parameters with the parameters of the actual capacitor equivalent model, a voltage differential error propagation mechanism is introduced to establish a mapping relationship between parameter error and voltage response, constructing a three-dimensional dynamic error model to achieve quantitative evaluation of the filter capacitor. This invention overcomes the limitations of traditional monitoring technologies that require equipment disassembly or shutdown testing, fully utilizes existing voltage and current sensor resources in the control system, and realizes online and real-time monitoring of the health status of the detection platform, significantly improving the engineering practicality and economy of the monitoring technology.

[0066] The following are embodiments of the apparatus of the present invention, which can be used to execute embodiments of the method of the present invention. For details not disclosed in the apparatus embodiments, please refer to the embodiments of the method of the present invention.

[0067] Example 5 Please see Figure 3 This invention provides a health status monitoring system for an energy storage grid-connected testing platform, comprising: a primary fault judgment unit and a secondary fault judgment unit; wherein, The primary fault judgment unit is used to perform a primary fault judgment based on the output-side filtered three-phase current of the energy storage grid-connected detection platform: if the output-side filtered three-phase current is normal, the healthy status monitoring result is output and the monitoring process ends; if the output-side filtered three-phase current is abnormal, the process jumps to execute the steps of the secondary fault judgment unit. The secondary fault judgment unit is used to perform secondary fault judgment based on the output side filtering three-phase voltage of the energy storage grid-connected detection platform: if the output side filtering three-phase voltage is normal, the filter capacitor status is detected and the health status monitoring result of the energy storage grid-connected detection platform is output according to the detection result; if the output side filtering three-phase voltage has a missing level, the insulated gate bipolar transistor (IGBT) status is detected and the health status monitoring result of the energy storage grid-connected detection platform is output according to the detection result.

[0068] Example 6 In one embodiment of the present invention, a computer device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used to execute the operation of a health status monitoring method for an energy storage grid-connected testing platform.

[0069] Example 7 In one embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM (Random Access Memory) or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the energy storage grid-connected monitoring platform health status monitoring method in the above embodiments.

[0070] In summary, existing energy storage grid-connected monitoring platforms focus solely on IGBTs for health monitoring, neglecting filter capacitors and failing to comprehensively assess the platform's health status. Furthermore, current IGBT monitoring methods suffer from operational complexity, require shutdown, are difficult to implement online, or are prone to inaccurate monitoring. Moreover, there is a lack of methods adapted to platform operating conditions for simultaneous quantitative assessment and aging localization of IGBTs and filter capacitors. Existing sensor resources on the platform are not fully utilized, some solutions require disassembly / shutdown testing, making real-time online monitoring difficult, and they cannot accurately identify the coupling characteristics of aging across multiple IGBT components, thus failing to provide precise guidance for preventative maintenance. The technical solution provided by this invention comprehensively monitors two core components, IGBTs and filter capacitors, to fully and accurately assess the overall health status of the testing platform, avoiding the risk of missed fault detection due to single monitoring. Relying on existing sensors in the energy storage grid-connected testing platform, it achieves online and real-time monitoring of the platform's health status without disassembling components or shutting down the system, improving engineering practicality and economy. It can accurately achieve quantitative assessment, aging indicator mapping, and device location for IGBTs and filter capacitors, and can also identify the coupling characteristics of IGBT single / dual / triple aging, providing clear guidance for preventative maintenance.

[0071] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0072] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0073] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0074] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for monitoring the health status of an energy storage grid-connected testing platform, characterized in that, Includes the following steps: Step 1: Perform a fault judgment based on the three-phase current after filtering on the output side of the energy storage grid-connected detection platform: If the three-phase current after filtering on the output side is normal, output the healthy status monitoring result and end the monitoring process. If the three-phase current after filtering on the output side is abnormal, then proceed to step 2. Step 2: Perform secondary fault judgment based on the three-phase voltage before filtering on the output side of the energy storage grid-connected testing platform: If the three-phase voltage before filtering on the output side is normal, perform filter capacitor status detection and output the health status monitoring result of the energy storage grid-connected testing platform according to the detection result. If the three-phase voltage levels are missing before the output side filter, the status of the Insulated Gate Bipolar Transistor (IGBT) is detected, and the health status monitoring result of the energy storage grid connection detection platform is output based on the detection result.

2. The method for monitoring the health status of an energy storage grid-connected testing platform according to claim 1, characterized in that, If the three-phase voltage before filtering on the output side is normal, the step of performing filter capacitor status detection and outputting the health status monitoring result of the energy storage grid-connected testing platform based on the detection result includes the following steps for selecting the monitoring time point: The noise-reduced capacitor branch current and the voltage across the capacitor are substituted into the equivalent model of the filter capacitor. The actual equivalent parameters of the filter capacitor corresponding to the selected monitoring time point are obtained through the parameter identification algorithm. The actual equivalent parameters of the filter capacitor are compared with the capacitor reference parameters to obtain the parameter deviation value. Based on the actual equivalent parameters of the filter capacitor and the parameter deviation value, the voltage differential error value is derived and calculated using the voltage differential error propagation mechanism. The parameter deviation value is compared with the preset threshold range of parameter deviation, and the voltage differential error value is compared with the preset threshold range of voltage differential error. Based on the comparison result, the filter capacitor status detection result at the selected monitoring time point is output.

3. The method for monitoring the health status of an energy storage grid-connected testing platform according to claim 2, characterized in that, In the steps of comparing the parameter deviation value with the preset threshold range of parameter deviation, comparing the voltage differential error value with the preset threshold range of voltage differential error, and outputting the filter capacitor status detection result at the selected monitoring time point based on the comparison result, if the parameter deviation value is within the preset threshold range of parameter deviation and the voltage differential error value is within the preset threshold range of voltage differential error, then the filter capacitor status detection result is normal; otherwise, the filter capacitor status detection result is deteriorated.

4. The method for monitoring the health status of an energy storage grid-connected testing platform according to claim 2, characterized in that, If the three-phase voltage before filtering on the output side is normal, then in the step of detecting the status of the filter capacitor and outputting the health status monitoring result of the energy storage grid-connected detection platform based on the detection result, multiple monitoring time points are set according to the preset time monitoring interval when detecting the status of the filter capacitor.

5. The method for monitoring the health status of an energy storage grid-connected testing platform according to claim 1, characterized in that, If the three-phase voltage before the output side filter has a missing level, the steps for performing IGBT state detection and outputting the health status monitoring results of the energy storage grid-connected testing platform based on the detection results include: Obtain the overall transient loss data of the three phases of the IGBT; Based on the overall transient loss data of IGBT three phases, the current-power ripple spectrum is introduced as an aging characteristic quantity. The characteristic parameters strongly correlated with IGBT aging are extracted by fast Fourier transform to obtain the aging characteristic parameters. The aging type is identified and the aging device is located based on the aging characteristic parameters, and the IGBT status detection result is output based on the identification and location results.

6. The method for monitoring the health status of an energy storage grid-connected testing platform according to claim 5, characterized in that, The steps to obtain the overall transient loss data of the three phases of an IGBT include: Collect operating parameters; wherein, the operating parameters include: the on-current, voltage, and temperature of the IGBT three-phase bridge arm, as well as the platform switching frequency and pulse width modulation timing parameters; The collected operating parameters are input into a pre-constructed three-phase overall transient loss model, which calculates and outputs the original IGBT three-phase overall transient loss data. The original IGBT three-phase overall transient loss data is denoised and filtered to remove interference components, and the final IGBT three-phase overall transient loss data is obtained. The construction steps of the three-phase overall transient loss model include: collecting IGBT single-phase operating data and establishing a conduction characteristic model; based on the conduction characteristic model, combining the calculation principles of IGBT conduction loss and switching loss, incorporating the switching frequency and pulse width modulation timing parameters of the energy storage grid-connected detection platform, and establishing a single-phase positive half-wave transient loss model applicable only to the single-phase positive half-wave interval of IGBT; based on the single-phase positive half-wave transient loss model and the symmetrical operating characteristics of the three-phase circuit, deriving the transient loss components of the second and third phases respectively through phase mapping; integrating and verifying the single-phase positive half-wave transient loss model and the transient loss components of the second and third phases to form a three-phase overall transient loss model that can completely characterize the power loss variation law of the three-phase bridge arm of IGBT during the entire conduction and switching process.

7. The method for monitoring the health status of an energy storage grid-connected testing platform according to claim 5, characterized in that, The steps for identifying aging types and locating aging devices based on aging characteristic parameters, and outputting IGBT condition detection results based on the identification and location results, include: The aging characteristic parameters are compared with the standard data in the IGBT manual, or compared with the preset aging threshold to determine whether the aging characteristic parameters exceed the normal range. If they do not exceed the normal range, the IGBT status detection result is normal. If they exceed the normal range, the aging mode of the IGBT and the location of the aging device are identified by combining the differences in the spectral characteristics corresponding to different aging combinations of single, dual, and triple transistors.

8. A health status monitoring system for an energy storage grid-connected testing platform, characterized in that, include: A primary fault diagnosis unit and a secondary fault diagnosis unit; wherein, The primary fault judgment unit is used to perform a primary fault judgment based on the output-side filtered three-phase current of the energy storage grid-connected detection platform: if the output-side filtered three-phase current is normal, the healthy status monitoring result is output and the monitoring process ends; if the output-side filtered three-phase current is abnormal, the process jumps to execute the steps of the secondary fault judgment unit. The secondary fault judgment unit is used to perform secondary fault judgment based on the output side filtering three-phase voltage of the energy storage grid-connected detection platform: if the output side filtering three-phase voltage is normal, the filter capacitor status is detected and the health status monitoring result of the energy storage grid-connected detection platform is output according to the detection result; if the output side filtering three-phase voltage has a missing level, the insulated gate bipolar transistor (IGBT) status is detected and the health status monitoring result of the energy storage grid-connected detection platform is output according to the detection result.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the health status monitoring method for the energy storage grid-connected testing platform as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the health status monitoring method of the energy storage grid-connected testing platform as described in any one of claims 1 to 7.

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