Power conversion device failure prediction method, apparatus, and power conversion system

Abstract

The application relates to a power conversion equipment fault prediction method and device and a power conversion system. The power conversion equipment fault prediction method comprises the following steps: obtaining the output voltage of a detection coil multiple times in a preset time period, extracting each output frequency corresponding to each output voltage of the detection coil, and predicting the fault occurrence time of the power conversion equipment according to the change trend of each output frequency. The power conversion equipment fault prediction device comprises a detection coil and a data processing device, the detection coil is connected with the data processing device, and the detection coil is a closed coil; the data processing device is used for obtaining the output voltage of the detection coil, extracting the corresponding output frequency, and predicting the fault occurrence time according to the change trend of each output frequency. The power conversion equipment fault prediction method, device and power conversion system realize fault prediction of the power conversion equipment, and further improve the reliability of the power conversion equipment operation.

Description

Fault prediction methods, devices and power conversion systems for power conversion equipment Technical Field

[0001] This application relates to the field of fault prediction technology, and in particular to a fault prediction method, device and power conversion system for power conversion equipment. Background Technology

[0002] With the continuous development of microelectronics technology, the level of informatization, intelligence, and electrification of modern equipment is constantly improving. Power conversion equipment such as DC / AC inverters and DC / DC power supplies are becoming increasingly widely used as core equipment in modern equipment. The reliability of power conversion equipment is an important guarantee for the working performance of modern equipment. In power conversion equipment, the performance degradation of electronic components is the fundamental reason affecting the reliability of power conversion equipment.

[0003] Traditional methods for testing electronic components involve using sensors such as current transformers and Hall effect sensors to monitor the current and voltage signals of power electronic devices in power conversion equipment online, thereby obtaining fault information about the power conversion equipment circuits, modules, or systems. However, this method can only determine whether a fault has occurred based on real-time detected data and detect existing faults, making traditional methods for testing electronic components unreliable. Summary of the Invention

[0004] Therefore, it is necessary to provide a fault prediction method and apparatus that can predict the degradation of power conversion equipment in order to address the above-mentioned technical problems.

[0005] Firstly, a method for predicting faults in power conversion equipment is provided, including:

[0006] The output voltage of the detection coil is acquired multiple times within a preset time period; the detection coil induces electromagnetic induction with the conduction circuit of the switching transistor in the power conversion device;

[0007] Extract each output frequency corresponding to each output voltage of the detection coil;

[0008] Based on the changing trends of the output frequencies, the failure time of the power conversion device is predicted.

[0009] In one embodiment, predicting the failure time of the power conversion device based on the changing trends of each of the output frequencies includes:

[0010] Based on the variation pattern of the difference between each output frequency and the reference frequency, the failure time of the power conversion device is predicted.

[0011] In one embodiment, extracting the output frequencies corresponding to the output voltages of the detection coil includes:

[0012] The oscillation period of each output voltage is obtained based on the output voltage of the detection coil.

[0013] The frequency of each output voltage is obtained based on the oscillation period of each output voltage.

[0014] In a second aspect, a fault prediction device for power conversion equipment is provided, comprising a detection coil and a data processing device, wherein the detection coil is connected to the data processing device, the detection coil is a closed coil, and the detection coil generates electromagnetic induction with the conduction line of a switching transistor in the power conversion equipment;

[0015] The data processing device is used to acquire the output voltage of the detection coil multiple times within a preset time period, extract each output frequency corresponding to each output voltage of the detection coil, and predict the fault occurrence time of the power conversion device based on the changing trend of each output frequency.

[0016] In one embodiment, the detection coil is symmetrical about the conduction path of the switch transistor under test.

[0017] In one embodiment, the number of detection coils is equal to the number of switches under test, and each detection coil corresponds to detecting one switch under test.

[0018] In one embodiment, the power conversion device fault prediction device further includes a housing, and the detection coil is disposed within the housing.

[0019] In one embodiment, the detection coil is a Rogowski coil.

[0020] Thirdly, a power conversion system is provided, including a power conversion device and a power conversion device fault prediction device as described above.

[0021] In one embodiment, the switching transistor in the power conversion device is a power switching device, and the detection coil is used to detect the transient current characteristics of the switching transistor. The detection coil and the conduction line of the switching transistor generate electromagnetic induction to induce a voltage.

[0022] The aforementioned power conversion equipment fault prediction method, device, and system include the following: The power conversion equipment fault prediction method involves repeatedly acquiring the output voltage of a detection coil within a preset time period. The detection coil induces electromagnetic induction with the conduction circuit of a switching transistor within the power conversion equipment. Then, the output frequencies corresponding to each output voltage are extracted. Based on the changing trends of these output frequencies, the timing of a power conversion equipment fault is predicted. By leveraging the electromagnetic induction between the detection coil and the conduction circuit of the switching transistor within the power conversion equipment, repeatedly acquiring the output voltage of the detection coil within a preset time period, extracting the corresponding output frequencies, analyzing the changing trends of the output frequencies, and predicting the timing of a power conversion equipment fault, fault prediction of the power conversion equipment is achieved, thereby improving the reliability of the power conversion equipment operation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 is a flowchart illustrating a power conversion device fault prediction method in one embodiment;

[0025] Figure 2 is a flowchart illustrating a power conversion device fault prediction method in another embodiment;

[0026] Figure 3 is a schematic diagram of the structure of a power conversion equipment fault prediction device in one embodiment;

[0027] Figure 4 is an equivalent circuit diagram of the switching transient of the switching transistor in a power conversion device in one embodiment;

[0028] Figure 5 is a transient waveform diagram of the switching current of the switching transistor in a power conversion device in one embodiment;

[0029] Figure 6 is a schematic diagram of the induced voltage waveform of a power conversion equipment fault prediction device in one embodiment;

[0030] Figure 7 is a schematic diagram of the relationship between the power conversion equipment fault prediction device and the conductive line in one embodiment;

[0031] Figure 8 is a schematic diagram of the relationship between the power conversion equipment fault prediction device and the conduction line in another embodiment. Detailed Implementation

[0032] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0034] The power conversion equipment prediction method, apparatus and system provided in this application can predict the faults of power conversion equipment.

[0035] In one embodiment, as shown in Figure 1, a fault prediction method for power conversion equipment is provided. This method can be executed by a data processing device. Specifically, the data processing device can be a data processing device already present in the power conversion equipment; simply adding corresponding functions to the existing data processing device can save hardware costs. Alternatively, it can be a separately designed data processing device with corresponding functions to ensure the accuracy of the prediction results. The fault prediction method for power conversion equipment is used to predict faults in power conversion equipment. Specifically, a power conversion equipment is a device that converts electrical energy from one form to another. The change in the form of electrical energy can be from DC power to AC power, from AC power to DC power, or from one voltage value to another. For example, a DC / DC power supply is a power conversion device that can convert DC power into another fixed or adjustable DC voltage. The fault prediction method for this power conversion equipment includes:

[0036] Step 102: Acquire the output voltage of the detection coil multiple times within a preset time period.

[0037] In this process, the detection coil undergoes electromagnetic induction with the conduction circuit of the switching transistor in the power conversion device.

[0038] Within a preset time period, the data processing device continuously acquires the induced voltage of the detection coil to provide more comprehensive monitoring of the power conversion equipment. For example, the output voltage of the detection coil could be acquired daily for a month. Alternatively, the output voltage of the detection coil could be acquired discretely at intervals to reduce the workload of fault prediction for the power conversion equipment. For example, the induced voltage of the detection coil could be acquired every month.

[0039] A switching transistor is a power device that turns a circuit on or off, including transistors and field-effect transistors (FETs). Power conversion equipment can control the on / off time ratio of the switching transistor through circuitry, allowing the transistor to pulse-modulate the input voltage and thus change the form of electrical energy. The way power conversion equipment controls the on / off state of the switching transistor can be used to control the voltage at one of its terminals. For example, when the switching transistor in the power conversion equipment is an enhancement-mode FET, no current flows between the source and drain when there is no voltage at the gate; in this case, the enhancement-mode FET is in the off state. When a forward voltage is applied to the gate, once the forward voltage exceeds a certain threshold, a drain-to-source current can be formed, at which point the enhancement-mode FET is in the on state.

[0040] The conduction path of a switching transistor refers to the path through which current flows from one terminal of the transistor to the other. For example, when the switching transistor is a field-effect transistor (FET), the conduction path can be a path through which current flows from the drain to the source, or from the source to the drain.

[0041] The detection coil induces an electromagnetic induction with the conduction path of the switching transistor within the power conversion device. The switching transistor is typically soldered onto the circuit board of the power conversion device. To achieve this electromagnetic induction, a detection coil can be designed and embedded within the circuit board. The switching transistor, controlled by other components in the power conversion device, is either in a conducting or cut-off state. During this process, a transient current is generated in the conduction path of the switching transistor, which produces a magnetic field around the conduction path. Simultaneously, the detection coil is located within this magnetic field, thus inducing a voltage. The oscillation frequency of this induced voltage is the same as the oscillation frequency of the transient current; therefore, the oscillation frequency of the current in the conduction path of the switching transistor can be obtained from the oscillation frequency of the induced voltage in the detection coil.

[0042] Step 104: Extract the output frequencies corresponding to each output voltage of the detection coil.

[0043] Different output voltages are obtained at different times, and each output voltage corresponds to a frequency. The corresponding frequency can be obtained based on some parameters in the voltage data. Before extracting and detecting the output frequencies corresponding to each output voltage of the coil, the output voltage must be measured. Specifically, the waveform of the output voltage can be displayed using an oscilloscope. An oscilloscope is a testing instrument that can observe the waveform curves of various signal amplitudes changing over time. It can also be used to test various electrical quantities, including voltage, current, frequency, and phase difference.

[0044] Step 106: Based on the changing trends of each output frequency, predict the failure time of the power conversion equipment.

[0045] Frequency is a characteristic parameter indicating the fault status of power conversion equipment. The trend of each output frequency means that based on the trend of each output frequency changing over time, a curve of the output frequency changing over time can be obtained. Then, the time when the power conversion equipment will fail can be predicted based on the curve.

[0046] In one embodiment, as shown in FIG2, step 106 includes step 206.

[0047] Step 206: Based on the variation pattern of the difference between each output frequency and the reference frequency, predict the failure time of the power conversion equipment.

[0048] The reference frequency is extracted from the reference voltage. The reference voltage can be the output voltage of the switching transistor in the power conversion equipment when it is tested by the detection coil at the factory, to characterize the standard operating state of the switching transistor. Alternatively, it can be the output voltage of the switching transistor in the power conversion equipment when it is tested by the detection coil after it has been operating for a period of time, before fault prediction is performed. This allows the reference voltage to better reflect the actual operating characteristics of the switching transistor, taking into account its service condition.

[0049] Based on the changing patterns of the differences between each output frequency and the reference frequency, the predicted failure time of the power conversion equipment can be calculated as follows: When the difference between each output frequency and the reference frequency is larger, considering the greater the deviation between the output frequencies and the reference frequency, the power conversion equipment is likely to fail sooner. Conversely, when the difference between each output frequency and the reference frequency is smaller, considering the smaller deviation between the output frequencies and the reference frequency, the power conversion equipment is likely to fail after a certain period. The difference between each output frequency and the reference frequency can be either the ratio or the difference between the output frequencies and the reference frequency. For example, when the ratio or difference between the output frequencies and the reference frequency exceeds a certain value or range, the power conversion equipment is predicted to fail soon. Using frequency to characterize the failure status of the power conversion equipment can improve the accuracy of predicting the failure time.

[0050] In one embodiment, the timing of a power conversion device failure can be predicted based on the variation of the difference between each output voltage and the reference voltage. The reference voltage can be the output voltage of the switching transistor in the power conversion device when it is manufactured and tested by the detection coil, representing the standard operating state of the switching transistor. Alternatively, it can be the output voltage of the switching transistor in the power conversion device after it has been operating for a period of time, before fault prediction is performed, so that the reference voltage better reflects the actual operating characteristics of the switching transistor, taking into account its service condition.

[0051] Based on the changing patterns of the differences between each output voltage and the reference voltage, the failure time of the power conversion equipment can be predicted as follows: When the difference between each output voltage and the reference voltage is larger, considering the greater the deviation between the output voltage and the reference voltage, the power conversion equipment is predicted to fail sooner. When the difference between each output voltage and the reference voltage is smaller, considering the smaller deviation between the output voltage and the reference voltage, the power conversion equipment is predicted to fail after a certain period of time. The difference between each output voltage and the reference voltage can be either the ratio of the output voltage to the reference voltage or the difference between the output voltage and the reference voltage. For example, when the ratio or difference between the output voltage and the reference voltage exceeds a certain value or range, the power conversion equipment is predicted to fail soon. When using output voltage to characterize the failure status of the power conversion equipment, the output voltage can be easily measured by relevant devices, thus simplifying the failure prediction process.

[0052] In one embodiment, as shown in FIG2, step 104 includes steps 202 and 204.

[0053] Step 202: Obtain the oscillation period of each output voltage based on the output voltage of the detection coil.

[0054] The changes in each output voltage over time exhibit certain patterns, and the oscillation period of each output voltage can be obtained based on these patterns. For example, the relationship between each output voltage and time can be approximated as a sine wave. Since a sine wave has a certain periodicity, the oscillation period of each output voltage can be obtained from the period of the sine wave. When observing the waveform of the output voltage, an oscilloscope can be used, and the oscillation period of the output voltage can be directly read from the oscilloscope.

[0055] Step 204: Obtain the frequency of the output voltage based on the oscillation period of each output voltage.

[0056] The frequency corresponding to each output voltage can be obtained by taking the reciprocal of the oscillation period of each output voltage.

[0057] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0058] The aforementioned fault prediction method for power conversion equipment includes acquiring the output voltage of a detection coil multiple times within a preset time period. The detection coil induces electromagnetic induction with the conduction circuit of a switching transistor within the power conversion equipment. Then, the output frequencies corresponding to each output voltage of the detection coil are extracted. Based on the changing trends of these output frequencies, the timing of a fault in the power conversion equipment is predicted. This method enables fault prediction of the power conversion equipment and improves its operational reliability.

[0059] Based on the same inventive concept, this application also provides a power conversion equipment fault prediction device for implementing the power conversion equipment fault prediction method described above. The solution provided by this device is similar to the implementation scheme described in the above method; therefore, the specific limitations in one or more power conversion equipment fault prediction device embodiments provided below can be found in the limitations of the power conversion equipment fault prediction method described above, and will not be repeated here.

[0060] In one embodiment, a power conversion device fault prediction device is provided, referring to Figure 3, including a detection coil 300 and a data processing device. The detection coil is connected to the data processing device. The detection coil is a closed coil, and electromagnetic induction occurs between the detection coil and the conduction line of the switching transistor in the power conversion device. The data processing device is not shown in the figure.

[0061] The data processing device is used to acquire the output voltage of the detection coil 300 multiple times within a preset time period, extract the output frequency corresponding to each output voltage of the detection coil 300, and predict the fault occurrence time of the power conversion equipment based on the changing trend of each output frequency.

[0062] The detection coil is a closed loop, with its start and end points connected to form a circuit. This connection can be a direct connection between the start and end points of the detection coil, or an indirect connection between the start and end points and the ends of other devices. The detection coil can be rectangular, circular, etc., and its material can be copper, aluminum, etc.

[0063] In this embodiment, the electromagnetic induction between the detection coil 300 and the conduction circuit of the switching transistor in the power conversion device means that when the power conversion device controls the switching transistor to be turned on and off through the circuit, the current in the conduction circuit of the switching transistor will change. The changing current can generate an induced electromotive force in the detection coil 300, and the generated induced electromotive force is the output voltage of the detection coil.

[0064] Furthermore, the data processing device may include a data acquisition module, a data extraction module, and a data analysis module. The data acquisition module acquires the output voltage of the detection coil 300 within a preset time period. The data extraction module extracts the output frequencies corresponding to each output voltage of the detection coil 300. The data analysis module predicts the failure time of the power conversion device based on the changing trend of the output frequencies.

[0065] Furthermore, in one embodiment, when the data processing device predicts the failure time of the power conversion device based on the changing trends of each output frequency, the data analysis module may specifically predict the failure time of the power conversion device based on the changing patterns of the differences between each output frequency and the reference frequency.

[0066] Furthermore, in one embodiment, when the data processing device extracts the output frequencies corresponding to the output voltages of the detection coil, the data extraction module can specifically obtain the oscillation period of each output voltage based on the output voltage of the detection coil, and obtain the frequency of each output voltage based on the oscillation period of each output voltage.

[0067] Each module in the aforementioned data processing device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the operations corresponding to each module.

[0068] In one embodiment, the detection coil 300 of the power conversion device fault prediction device is symmetrical about the conduction line of the switch transistor under test.

[0069] Specifically, the symmetry of the detection coil 300 with respect to the conduction path of the switch under test means that the detection coil 300 has the same structure and dimensions on both sides of the conduction path of the switch under test. The detection coil 300 may include two identical detection sub-coils, namely a first detection coil 310 and a second detection coil 320, which are respectively disposed on both sides of the conduction path of the switch under test. The two detection sub-coils have the same shape, material, and size, and are equidistant from the conduction path of the switch under test to form a symmetrical structure.

[0070] Simultaneously, the two detection sub-coils are interconnected and connected to the oscilloscope to form a closed loop. Specifically, the first end of the first detection coil 310 is connected to the first end of the second detection coil 320, and the second end of the first detection coil 310 is connected to the first probe of the oscilloscope. The first end of the second detection coil 320 is connected to the first end of the first detection coil 310, and the second end of the second detection coil 320 is connected to the second probe of the oscilloscope. The first probe of the oscilloscope can be the positive terminal of the induced voltage, and the second probe of the oscilloscope can be the negative terminal of the induced voltage. The induced voltage generated by the detection coil 300 is transmitted to the oscilloscope through the probe, and the waveform of the induced voltage is displayed on the oscilloscope. Furthermore, the detection coil 300 is placed close to the conduction circuit of the switch transistor under test to more sensitively sense current changes in the conduction circuit.

[0071] In this embodiment, by placing the detection coil 300 symmetrically to the conduction path of the switching transistor in the power conversion device, any current other than that in the conduction path of the switching transistor generates a magnetic field parallel to or opposite in polarity to the detection coil 300, resulting in no induced voltage output. Simultaneously, the magnetic flux generated in the detection coil 300 by the current in the conduction path of the switching transistor is doubled, further enhancing the induced voltage of the detection coil 300. This reduces interference from other currents in the power conversion device and improves the accuracy of the output voltage of the power conversion device fault prediction device.

[0072] In one embodiment, the number of detection coils 300 in the power conversion equipment fault prediction device is equal to the number of switches under test, with each detection coil 300 corresponding to one switch under test. This ensures that each switch under test has a corresponding detection coil 300 for detection, which helps improve the accuracy of fault prediction results.

[0073] In one embodiment, the number of detection coils 300 in the power conversion equipment fault prediction device exceeds the number of transistors under test, and each transistor under test can be detected by multiple detection coils 300. When some detection coils are damaged and cannot work normally, the remaining detection coils can continue to detect the transistors under test normally, thereby ensuring the accuracy of fault prediction by the power conversion equipment fault prediction device.

[0074] In one embodiment, the number of detection coils 300 in the power conversion equipment fault prediction device is less than the number of the switch transistors under test. By setting detection coils 300 for the switch transistors under test that require key monitoring, the cost of predicting faults in the power conversion equipment fault prediction device can be reduced.

[0075] In one embodiment, the power conversion device fault prediction device includes a housing 410, and a detection coil 300 is disposed within the housing 410. The surface of the housing 410 has connection ports 200, which can be two, including a first connection port 210 and a second connection port 220. The detection coil 300 is connected to an oscilloscope probe via the connection ports 200. The second end of the first detection coil 310 is connected to the first probe of the oscilloscope via the first connection port 210, and the second end of the second detection coil 320 is connected to the second probe of the oscilloscope via the second connection port 220. The housing 410 of the power conversion device fault prediction device can reduce damage to the detection coil 300, and the connection ports 200 on the surface of the housing 410 facilitate connection of the detection coil to other devices.

[0076] In one embodiment, the detection coil 300 of the power conversion equipment fault prediction device can be a Rogowski coil. A Rogowski coil is a hollow toroidal coil that features a wide detection frequency band, high accuracy, and small size, making it suitable for measuring AC current over a wide frequency range, especially high-frequency, high-current measurements. When the detection coil 300 of the power conversion equipment fault prediction device is a Rogowski coil, the accuracy of fault prediction can be improved.

[0077] The aforementioned power conversion equipment fault prediction device includes a detection coil 300 and a data processing device. The detection coil 300 is connected to the data processing device and is a closed coil. The detection coil 300 generates electromagnetic induction with the conduction circuit of the switching transistor in the power conversion equipment. The data processing device is used to acquire the output voltage of the detection coil 300 multiple times within a preset time period, extract each output frequency corresponding to each output voltage of the detection coil 300, and predict the fault occurrence time of the power conversion equipment based on the changing trend of each output frequency.

[0078] When the current in the conduction circuit of the switching transistor in the power conversion equipment changes, the magnetic flux in the detection coil 300 also changes. This changing magnetic flux induces a voltage in the detection coil 300, and the induced voltage signal is then transmitted to the data processing device. Based on the received signals of each induced voltage, the data processing device extracts the corresponding induced frequency, analyzes the trend of frequency changes, and predicts the time of fault occurrence. This power conversion equipment fault prediction device enables the prediction of power conversion equipment faults, improving the reliability of the power conversion equipment.

[0079] In one embodiment, a power conversion system is provided, including a power conversion device and a power conversion device fault prediction device. The power conversion system can be used to predict the time of failure of the power conversion device. Specific steps for fault prediction include connecting the power conversion device fault prediction device to the power conversion device, acquiring the output voltage of a detection coil 300, extracting the output frequencies corresponding to each output voltage of the detection coil 300, and then predicting the time of failure of the power conversion device based on the changing trends of each output frequency. Since the current in the conducting circuit of the switching transistor changes before and after degradation, the output voltage of the detection coil 300 acquired each time will be different, and furthermore, the extracted output frequencies will also be different each time. However, the changing trends of the output frequencies can exhibit certain characteristics, and after analysis by the data processing device, the time of failure can be predicted.

[0080] In one embodiment, the switching transistor in the power conversion device is a power switching device, and the detection coil 300 is used to detect the transient current characteristics of the switching transistor. The detection coil 300 and the conduction line of the switching transistor generate electromagnetic induction, and a voltage is induced.

[0081] The aforementioned power conversion system first connects a power conversion equipment fault prediction device to the power conversion equipment, then acquires the output voltage of the detection coil 300, extracts the output frequencies corresponding to each output voltage of the detection coil 300, and then predicts the fault occurrence time of the power conversion equipment based on the changing trends of each output frequency. This system can predict faults in power conversion equipment.

[0082] To better understand the above embodiments, a detailed explanation will be provided below with reference to a specific embodiment.

[0083] In one embodiment, the power conversion device fault prediction device includes a detection coil and a data processing device, wherein the detection coil 300 is a symmetrical Rogowski coil. The switching transient circuit of the power conversion device can be equivalently represented as a second-order LRC circuit, as shown in Figure 4. During the turn-on and turn-off process of the switching transistor, its conduction path can generate a transient oscillating current, the waveform of which is shown in Figure 5. The Rogowski coil can induce the transient oscillating current and generate an induced voltage proportional to the reciprocal of the transient oscillating current, the waveform of which is shown in Figure 6. Moreover, the oscillation frequency of the induced voltage of the Rogowski coil is the same as the oscillation frequency of the transient oscillating current. When the conduction path of the switching transistor is located symmetrically below the Rogowski coil, the current of any other traces, vias, and pads on the circuit board can be decomposed into three components in the X, Y, and Z directions, respectively. The current in the X and Y directions generates a magnetic field parallel to the Rogowski coil, resulting in zero coupling, and therefore no measurement output. The Z-direction current located outside the package 410 generates signals of opposite polarity in the two Rogowski coils, which cancel each other out, and therefore there is also no measurement output. It can prevent interference from current in lines other than the conductive lines. The power conversion equipment fault prediction device is directly attached to the circuit of the power conversion equipment without changing the circuit design and layout of the power conversion equipment.

[0084] Power conversion devices can be DC / DC power supplies. A DC / DC power supply is a direct current converter that can convert one type of DC power into another fixed or adjustable DC voltage. A DC / DC power supply circuit can be equivalent to a second-order LRC system. During the switching process of the transistor, its circuit will oscillate, with an oscillation frequency of f0, where f0 = (ω0) / (ω0). 2 -ξ 2 ) 1 / 2 Where ξ = R / 2L, ω0 = 1 / (LC) 1 / 2 ξ represents the damping coefficient of the damped oscillation, ω0 represents the resonant angular frequency, R represents resistance, L represents inductance, and C represents capacitance. When the switching transistor or other components in a DC / DC power supply circuit degrade, the current oscillation frequency of the circuit changes to f1, and the oscillation frequency of the induced voltage in the Rogowski coil also changes to f1. By comparing the normalized oscillation frequencies f1 / f0 of the induced voltage before and after degradation, the trend of DC / DC power supply degradation can be obtained.

[0085] The specific steps for predicting DC / DC power supply faults include designing a Rogowski coil and placing it directly above the conduction path of the switching transistor. The components at both ends of the conduction path should be spaced apart to allow for the insertion of a power conversion device fault prediction device. Alternatively, the Rogowski coil can be embedded and designed into the circuit board. The power conversion device fault prediction device is placed perpendicular to the conduction path of the switching transistor; specifically, the Rogowski coil can be placed perpendicular to the conduction path of the switching transistor, as shown in Figure 7. Figure 7 includes a top view of the power conversion device fault prediction device. The connection port 200 is visible from the outside of the package 410; the detection coil 300 is located inside the package 410 and is not visible from the outside. The induced voltage of the Rogowski coil is then acquired, and the corresponding oscillation frequency is extracted from the induced voltage waveform to obtain the DC / DC power supply degradation trend and predict the time of fault occurrence. Through this process, fault prediction of the DC / DC power supply can be achieved, further improving the reliability of DC / DC power supply operation.

[0086] Power conversion devices can also be DC / AC inverters. A DC / AC inverter is a device that can convert DC voltage or current into AC voltage or current. A DC / AC inverter can be equivalent to an LRC second-order system. During the switching process of the transistor, its circuit will oscillate, and the oscillation frequency is f0, where f0 = (ω0) / (ω0). 2 -ξ 2 ) 1 / 2 Where ξ = R / 2L, ω0 = 1 / (LC) 1 / 2 ξ represents the damping coefficient of the damped oscillation, ω0 represents the resonant angular frequency, R represents resistance, L represents inductance, and C represents capacitance. When the switching transistor or other components in the DC / AC power supply circuit degrade, the current oscillation frequency of the circuit changes to f1, and the oscillation frequency of the induced voltage in the Rogowski coil also changes to f1. By comparing the normalized oscillation frequencies f1 / f0 of the induced voltage before and after degradation, the degradation trend of the DC / AC inverter can be obtained.

[0087] The specific steps for predicting DC / AC inverter faults include designing a Rogowski coil and placing it directly above the conduction path of the switching transistor. The components at both ends of the conduction path should be spaced apart to allow for the insertion of a power conversion device fault prediction device. Alternatively, the Rogowski coil can be embedded and designed into the circuit board. The power conversion device fault prediction device is placed perpendicular to the conduction path of the switching transistor; specifically, the Rogowski coil can be placed perpendicular to the conduction path of the switching transistor, as shown in Figure 8. Figure 8 includes a top view of the power conversion device fault prediction device. The connection port 200 is visible from outside the enclosure 410; the detection coil 300 is located inside the enclosure 410 and is not visible from the outside. The induced voltage of the Rogowski coil is then acquired, and the corresponding oscillation frequency is extracted from the induced voltage waveform to obtain the DC / AC inverter degradation trend and predict the time of fault occurrence. Through this process, fault prediction of the DC / AC inverter can be achieved, further improving the reliability of DC / AC inverter operation.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for predicting faults in power conversion equipment, characterized in that, include: The output voltage of the detection coil is acquired multiple times within a preset time period; the detection coil induces electromagnetic induction with the conduction circuit of the switching transistor in the power conversion device; Extract each output frequency corresponding to each output voltage of the detection coil; during the switching process of the switching transistor, the conducting circuit generates a transient oscillating current, and the output frequency of each output voltage is the same as the oscillation frequency of the transient oscillating current; predict the failure time of the power conversion device based on the changing trend of each output frequency; wherein, predicting the failure time of the power conversion device based on the changing trend of each output frequency includes: predicting the failure time of the power conversion device based on the changing law of the difference between each output frequency and the reference frequency.

2. The power conversion equipment fault prediction method according to claim 1, characterized in that, The step of extracting the output frequencies corresponding to each output voltage of the detection coil includes: obtaining the oscillation period of each output voltage based on each output voltage of the detection coil; and obtaining the frequency of each output voltage based on the oscillation period of each output voltage.

3. A fault prediction device for power conversion equipment, characterized in that, The device includes a detection coil and a data processing device. The detection coil is connected to the data processing device and is a closed coil. The detection coil induces electromagnetic induction with the conduction circuit of a switching transistor in a power conversion device. The data processing device is used to acquire the output voltage of the detection coil multiple times within a preset time period, extract the output frequency corresponding to each output voltage of the detection coil, and predict the failure time of the power conversion device based on the changing trend of each output frequency. The prediction of the failure time of the power conversion device based on the changing trend of each output frequency includes: predicting the failure time of the power conversion device based on the changing pattern of the difference between each output frequency and a reference frequency. During the switching process of the transistor, the conduction circuit generates a transient oscillating current, and the output frequency of each output voltage is the same as the oscillation frequency of the transient oscillating current.

4. The power conversion equipment fault prediction device according to claim 3, characterized in that, The detection coil is symmetrical about the conduction path of the switch transistor under test.

5. The power conversion equipment fault prediction device according to claim 3, characterized in that, The number of detection coils is equal to the number of switches to be tested, and each detection coil corresponds to one switch to be tested.

6. The power conversion equipment fault prediction device according to claim 3, characterized in that, It also includes a housing, and the detection coil is disposed inside the housing.

7. The power conversion equipment fault prediction device according to claim 3, characterized in that, The detection coil is a Rogowski coil.

8. A power conversion system, characterized in that, It includes power conversion equipment and a power conversion equipment fault prediction device as described in any one of claims 3-7.

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