Open-circuit fault diagnosis method and equipment applied to inverter power supply of hybrid power device
By analyzing the frequency domain and setting the drive mode of the inverter power supply of hybrid power devices, the problem of diagnosing open-circuit faults in the inverter power supply of hybrid power devices was solved, and efficient and accurate identification of open-circuit faults in Si IGBTs and SiC MOSFETs was achieved.
Patent Information
- Application Number
- CN202610106415.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-26
- Publication Date
- 2026-04-10
AI Technical Summary
Existing technologies are insufficient for effectively diagnosing open-circuit faults in hybrid power device inverters, especially open-circuit faults in the case of Si IGBTs and SiC MOSFETs connected in parallel.
By collecting the output voltage or current of the inverter power supply of the hybrid power device, performing frequency domain analysis, obtaining the amplitude of each harmonic and the total harmonic distortion rate, comparing the offset between the current state and the normal state, setting the driving mode, and making judgments within a preset number of times, open circuit faults are identified.
It achieves efficient and accurate diagnosis of open-circuit faults in the inverter power supply of hybrid power devices, and can distinguish between open-circuit faults in Si IGBTs and SiC MOSFETs.
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Figure CN121831599A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of power electronics and power conversion, in particular to an open-circuit fault diagnosis method and device applied to a hybrid power device inverter. BACKGROUND
[0002] With the continuous expansion of the application of inverter power supply in the fields of new energy, transportation electrification and industrial driving, higher efficiency, dynamic performance and reliability requirements are put forward for power devices in the inverter power supply. In order to balance the low conduction loss of Si IGBT (Insulate-Gate Bipolar Transistor) and the high-speed switching characteristics of SiC MOSFET (Metal Oxide Semiconductor Field Effect Transistor), the design method of parallel connection of the two types of devices to form a single hybrid power device (referred to as "hybrid device") is gradually adopted, so that they can jointly bear the current distribution and dynamic adjustment task in the same switching arm, thereby achieving a balance between cost, efficiency and performance.
[0003] However, it is difficult to diagnose the open-circuit fault of the hybrid power device inverter in the related art. SUMMARY
[0004] The purpose of the present application is to provide an open-circuit fault diagnosis method and device applied to a hybrid power device inverter, which can be used to diagnose the open-circuit fault of the hybrid power device inverter.
[0005] In view of the existing problems, the present application provides the following solutions: In a first aspect, the present application provides an open-circuit fault diagnosis method applied to a hybrid power device inverter, the hybrid power device inverter comprising parallelly connected Si IGBT and SiC MOSFET, the open-circuit fault diagnosis method applied to the hybrid power device inverter comprising: acquiring an output voltage or an output current of the hybrid power device inverter in a current state; performing frequency domain analysis on the acquired output voltage or output current of the hybrid power device inverter in the current state to obtain harmonic amplitude and total harmonic distortion of the hybrid power device inverter in the current state, and obtaining harmonic amplitude and total harmonic distortion of the hybrid power device inverter in a normal state; obtaining harmonic amplitude and total harmonic distortion offset of the hybrid power device inverter in the current state based on the harmonic amplitude and total harmonic distortion of the hybrid power device inverter in the current state and the normal state; comparing the harmonic amplitude offset of the hybrid power device inverter in the current state with the corresponding harmonic amplitude offset determination threshold, and comparing the total harmonic distortion rate offset of the hybrid power device inverter in the current state with the total harmonic distortion rate offset determination threshold, wherein if the same specific harmonic amplitude offset of the hybrid power device inverter in the current state is greater than the corresponding harmonic amplitude offset determination threshold, or the total harmonic distortion rate offset of the hybrid power device inverter in the current state is greater than the total harmonic distortion rate offset determination threshold, for more than a preset number of continuous detection periods, it is determined that the hybrid power device inverter in the current state has an open circuit fault.
[0006] In an embodiment, the open circuit fault diagnosis method applied to the hybrid power device inverter further comprises the step of setting the driving mode of the hybrid power device inverter, wherein the driving mode of the hybrid power device inverter includes IGBT driving mode and MOSFET driving mode, and wherein: when the hybrid power device inverter is in IGBT driving mode, Si IGBT is turned on first and then turned off compared with SiC MOSFET; when the hybrid power device inverter is in MOSFET driving mode, SiC MOSFET is turned on first and then turned off compared with Si IGBT. When it is determined that the hybrid power device inverter in the current state has an open circuit fault, if the hybrid power device inverter is in IGBT driving mode, it is determined that Si IGBT in the current state has an open circuit fault; if the hybrid power device inverter is in MOSFET driving mode, it is determined that SiC MOSFET in the current state has an open circuit fault.
[0007] In an embodiment, the step of setting the driving mode of the hybrid power device inverter comprises: The output current of the hybrid power device inverter in the current state is collected, and when the collected output current of the hybrid power device inverter in the current state is less than a current threshold, the driving mode of the hybrid power device inverter is set to IGBT driving mode; when the collected output current of the hybrid power device inverter in the current state is greater than or equal to the current threshold, the driving mode of the hybrid power device inverter is set to MOSFET driving mode.
[0008] In an embodiment, the harmonic amplitude offset of the hybrid power device inverter in the current state and the total harmonic distortion rate offset are obtained by formula (1) and formula (2) respectively: (1) (2) wherein, represents the harmonic amplitude offset of the hybrid power device inverter in the current state, represents the harmonic amplitude of the hybrid power device inverter in the current state, represents the harmonic amplitude of the hybrid power device inverter in the normal state, represents the total harmonic distortion offset of the hybrid power device inverter in the current state, represents the total harmonic distortion of the hybrid power device inverter in the current state, represents the total harmonic distortion of the hybrid power device inverter in the normal state.
[0009] In an embodiment, the hybrid power device inverter includes multiple operating conditions, and the harmonic amplitude offset and the total harmonic distortion offset of the hybrid power device inverter in the current state under different operating conditions are obtained by formula (3) and formula (4) respectively: (3) (4) wherein, represents the harmonic amplitude offset of the hybrid power device inverter in the current state, represents the harmonic amplitude of the hybrid power device inverter in the current state, represents the harmonic amplitude of the hybrid power device inverter in the current state, represents the harmonic amplitude of the hybrid power device inverter in the normal state, represents the total harmonic distortion offset of the hybrid power device inverter in the current state, represents the total harmonic distortion of the hybrid power device inverter in the current state, represents the total harmonic distortion of the hybrid power device inverter in the current state, represents the total harmonic distortion of the hybrid power device inverter in the normal state.
[0010] In one embodiment, the threshold values for determining the amplitude offset of the same harmonic under different operating conditions of the hybrid power device inverter are equal, and the threshold values for determining the total harmonic distortion rate offset of the hybrid power device inverter under different operating conditions are equal.
[0011] In one embodiment, the operating conditions of the hybrid power device inverter power supply include no-load, load, grid-connected, and off-grid.
[0012] In one embodiment, the output voltage or output current of the hybrid power device inverter power supply in the current state is analyzed in the frequency domain using the fast Fourier transform or discrete Fourier transform method.
[0013] Secondly, this application provides an open-circuit fault diagnosis device for a hybrid power device inverter power supply, wherein the hybrid power device inverter power supply includes parallel-connected Si IGBTs and SiC MOSFETs, and the open-circuit fault diagnosis device for the hybrid power device inverter power supply includes a data acquisition module, a frequency domain analysis module, a harmonic feature extraction module, and a fault determination module, wherein: The data acquisition module is used to: acquire the output voltage or output current of the hybrid power device inverter power supply in the current state; The frequency domain analysis module is used to: perform frequency domain analysis on the collected output voltage or output current of the hybrid power device inverter power supply to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the current state, and to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the normal state. The harmonic feature extraction module is used to: obtain the harmonic amplitude offset and total harmonic distortion offset of the hybrid power device inverter power supply in the current state based on the harmonic amplitude and total harmonic distortion rate of each harmonic in the current state and the normal state. The fault determination module is used to: compare the amplitude offset of each harmonic of the hybrid power device inverter power supply in the current state with the determination threshold of the corresponding harmonic amplitude offset, and compare the total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state with the determination threshold of the total harmonic distortion rate offset. If, within a consecutive detection period of more than or equal to a preset number of times, the amplitude offset of the same specific harmonic of the hybrid power device inverter power supply in the current state is greater than the determination threshold of the corresponding harmonic amplitude offset, or if the total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state is greater than the determination threshold of the total harmonic distortion rate offset, it is determined that the hybrid power device inverter power supply has an open circuit fault in the current state.
[0014] In one embodiment, the open-circuit fault diagnosis device applied to the hybrid power device inverter power supply further includes a drive mode setting module. The acquisition module is used to acquire the output current of the hybrid power device inverter power supply in the current state. The drive mode setting module is used to: set the drive mode of the hybrid power device inverter power supply to IGBT drive mode when the acquired output current of the hybrid power device inverter power supply is less than a current threshold, and set the drive mode of the hybrid power device inverter power supply to MOSFET drive mode when the acquired output current of the hybrid power device inverter power supply is greater than or equal to the current threshold. Specifically, when the inverter power supply of the hybrid power device is in IGBT drive mode, the SiIGBT turns on first and then turns off compared to the SiC MOSFET; when the inverter power supply of the hybrid power device is in MOSFET drive mode, the SiC MOSFET turns on first and then turns off compared to the SiIGBT. When the fault determination module determines that the hybrid power device inverter power supply has an open circuit fault in the current state, the fault determination module is further configured to: identify that the hybrid power device inverter power supply is in IGBT drive mode and determine that the SiIGBT has an open circuit fault in the current state; or, identify that the hybrid power device inverter power supply is in MOSFET drive mode and determine that the SiC MOSFET has an open circuit fault in the current state.
[0015] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a method and device for diagnosing open-circuit faults in hybrid power device inverters. The method involves acquiring the output voltage or current of the hybrid power device inverter in its current state, performing frequency domain analysis on the output voltage or current to obtain the amplitude and total harmonic distortion (THD) of each harmonic in the current state, and combining this with the obtained amplitude and THD of each harmonic in the normal state to obtain the offset of each harmonic amplitude and the offset of the THD in the current state. The method then compares the offset of each harmonic amplitude in the current state with the corresponding threshold values for the offset of the harmonic amplitude, and compares the offset of the THD in the current state with the threshold values for the THD offset. Based on the comparison results, it determines whether an open-circuit fault exists in the hybrid power device inverter in its current state. This method can efficiently and accurately diagnose whether an open-circuit fault exists in a hybrid power device inverter. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments 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.
[0017] Figure 1 This is a flowchart illustrating an open-circuit fault diagnosis method for a hybrid power device inverter power supply according to an embodiment of this application. Figure 2 This is a schematic diagram of a hybrid power device inverter power supply in one embodiment of this application; Figure 3 This is a schematic diagram of the turn-on and turn-off timing of Si IGBT and SiC MOSFET when the inverter power supply of the hybrid power device is in MOSFET drive mode in one embodiment of this application. Figure 4 This is a schematic diagram of the turn-on and turn-off timing of Si IGBT and SiC MOSFET when the inverter power supply of the hybrid power device is in IGBT drive mode according to one embodiment of this application. Detailed Implementation
[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0020] The inventors of this application discovered that the parallel physical structure of internal components in a hybrid device, along with consistent port voltages and a unified driving rhythm, means that even if one component experiences an open circuit, the other can still maintain normal conduction, preventing a noticeable interruption in the inverter's output waveform. Therefore, commonly used methods such as component voltage drop monitoring, single-transistor current detection, and switching transient comparison cannot be directly used to distinguish open-circuit faults within a hybrid device.
[0021] Therefore, given the existence of the aforementioned technical problems, such as Figure 1As shown, this application provides an open-circuit fault diagnosis method for a hybrid power device inverter power supply, which includes parallel Si IGBTs and SiCMOSFETs. The method is executed by a computer device, specifically by a terminal or server alone, or by both. The method includes the following steps S1 to S4: In step S1, the output voltage or output current of the hybrid power device inverter power supply in the current state is collected.
[0022] In step S2, frequency domain analysis is performed on the output voltage or output current of the hybrid power device inverter power supply in the current state (frequency domain analysis is performed on the output voltage or output current at a preset time interval) to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the current state, and the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the normal state are obtained.
[0023] In step S3, based on the harmonic amplitude and total harmonic distortion rate of the hybrid power device inverter power supply in the current state and normal state, the offset of the harmonic amplitude and the offset of the total harmonic distortion rate of the hybrid power device inverter power supply in the current state are obtained.
[0024] In step S4, the amplitude offset of each harmonic of the hybrid power device inverter in the current state is compared with the judgment threshold of the corresponding harmonic amplitude offset (the amplitude offset of the first harmonic is compared with the judgment threshold of the second harmonic amplitude offset, the amplitude offset of the second harmonic is compared with the judgment threshold of the second harmonic amplitude offset, and so on). The total harmonic distortion rate offset of the hybrid power device inverter in the current state is compared with the judgment threshold of the total harmonic distortion rate offset. If, within a consecutive detection period of more than or equal to a preset number of times, the amplitude offset of the same specific harmonic of the hybrid power device inverter in the current state is greater than the judgment threshold of the corresponding harmonic amplitude offset, or if the total harmonic distortion rate offset of the hybrid power device inverter in the current state is greater than the judgment threshold of the total harmonic distortion rate offset, it is determined that there is an open circuit fault in the hybrid power device inverter in the current state.
[0025] In one exemplary embodiment of this application, when any device in the hybrid power device inverter power supply is open-circuited (e.g., Si IGBT or SiC MOSFET), the reduction in the effective conducting branch will cause the hybrid power device to generate an additional equivalent dead time increment under the original driving rhythm. This change will be reflected in the output voltage or current of the hybrid power device inverter power supply as a measurable offset of a specific harmonic component. Therefore, the open-circuit fault of the hybrid power device inverter power supply can be diagnosed by measuring the offset of a specific harmonic component in the output voltage or current of the hybrid power device inverter power supply.
[0026] This application provides an open-circuit fault diagnosis method for hybrid power device inverters. The method acquires the output voltage or current of the hybrid power device inverter in its current state and performs frequency domain analysis to obtain the harmonic amplitude and total harmonic distortion (THD) of the inverter in the current state. Combining this with the obtained harmonic amplitude and THD of the inverter in its normal state, the method obtains the harmonic amplitude offset and THD offset of the inverter in its current state. The method then compares the harmonic amplitude offset with a corresponding threshold value, and compares the THD offset with a threshold value, determining whether an open-circuit fault exists in the inverter in its current state based on the comparison results. This method can efficiently and accurately diagnose open-circuit faults in hybrid power device inverters.
[0027] Below, for reference Figures 1 to 4 This application provides a detailed description of an open-circuit fault diagnosis method for hybrid power device inverter power supplies, wherein... Figure 1 This is a flowchart illustrating an open-circuit fault diagnosis method for a hybrid power device inverter power supply according to one embodiment of this application. Figure 2 This is a schematic diagram of a hybrid power device inverter power supply according to one embodiment of this application. Figure 3 This is a schematic diagram illustrating the turn-on and turn-off timing of the Si IGBT and SiC MOSFET when the inverter power supply of the hybrid power device is in MOSFET drive mode, according to one embodiment of this application. Figure 4 This is a schematic diagram of the turn-on and turn-off timing of Si IGBT and SiC MOSFET when the inverter power supply of the hybrid power device is in IGBT drive mode according to one embodiment of this application.
[0028] In one exemplary embodiment of this application, such as Figure 2As shown, the hybrid power device inverter of this application includes Si IGBTs and SiC MOSFETs connected in parallel; as an example, Figure 2 The diagram shows an N-channel Si IGBT and an N-channel enhancement-mode SiC MOSFET, wherein the collector of the N-channel Si IGBT is connected to the drain of the N-channel enhancement-mode SiC MOSFET, and the emitter of the N-channel Si IGBT is connected to the source of the N-channel enhancement-mode SiC MOSFET.
[0029] In one exemplary embodiment of this application, the Fast Fourier Transform (FFT) or Discrete Fourier Transform (DFT) methods can be used to perform frequency domain analysis on the acquired output voltage or output current of the hybrid power device inverter power supply in its current state. In other embodiments, equivalent digital spectrum analysis methods to the Fast Fourier Transform and Discrete Fourier Transform methods can also be used to achieve frequency domain analysis.
[0030] In one exemplary embodiment of this application, the harmonic amplitudes and total harmonic distortion (THD) of a hybrid power device inverter power supply under normal conditions can be obtained by offline or online calibration of the output voltage or output current of the hybrid power device inverter power supply under normal conditions. For example, the harmonic amplitudes and THD of the hybrid power device inverter power supply under normal conditions can be obtained by performing frequency domain analysis on the output voltage or output current of the hybrid power device inverter power supply under normal conditions.
[0031] In an exemplary embodiment of this application, the open-circuit fault diagnosis method applied to a hybrid power device inverter power supply further includes the step of setting the driving mode of the hybrid power device inverter power supply. The driving mode of the hybrid power device inverter power supply includes an IGBT driving mode and a MOSFET driving mode, wherein: when the hybrid power device inverter power supply is in the IGBT driving mode, the Si IGBT is turned on first and then turned off compared to the SiC MOSFET; when the hybrid power device inverter power supply is in the MOSFET driving mode, the SiC MOSFET is turned on first and then turned off compared to the Si IGBT.
[0032] In an exemplary embodiment of this application, the turn-on and turn-off timings of Si IGBT and SiC MOSFET when the hybrid power device inverter power supply is in MOSFET drive mode and the turn-on and turn-off timings of Si IGBT and SiC MOSFET when the hybrid power device inverter power supply is in IGBT drive mode are respectively as follows: Figure 3 and Figure 4 As shown, where, t Indicates time, t on t on1 These represent the MOSFET drive mode and the IGBT drive mode, respectively. t off t off1 These represent the turn-off delay times for MOSFET drive mode and IGBT drive mode, respectively. S SiC and S Si These represent the drive voltages of the SiC MOSFET and the Si IGBT, respectively.
[0033] In an exemplary embodiment of this application, taking a preset number of three times as an example, if within three or more consecutive detection cycles, the amplitude offset of the same specific harmonic in the current state of the hybrid power device inverter is greater than the determination threshold of the corresponding harmonic amplitude offset (for example, the amplitude offset of the first harmonic in the current state of the hybrid power device inverter is greater than the determination threshold of the first harmonic amplitude offset). k The amplitude offset of each harmonic is greater than that of the first harmonic. k If the total harmonic distortion rate (THR) offset of the hybrid power device inverter in the current state is greater than the THR offset threshold, it is determined that the hybrid power device inverter has an open circuit fault in the current state. For example, in each detection cycle, the THR offset and THR offset of the hybrid power device inverter in the current state are acquired once.
[0034] In one exemplary embodiment of this application, the threshold values for determining the amplitude offset of each harmonic and the threshold values for determining the total harmonic distortion rate offset can be preset or adaptively set based on the operating data of the hybrid power device inverter power supply under normal conditions and the allowable power quality fluctuation range.
[0035] In an exemplary embodiment of this application, when it is determined that the hybrid power device inverter power supply has an open-circuit fault in the current state, if the hybrid power device inverter power supply is in IGBT driving mode, it is determined that the Si IGBT has an open-circuit fault in the current state; if the hybrid power device inverter power supply is in MOSFET driving mode, it is determined that the SiC MOSFET has an open-circuit fault in the current state. That is, if, within a consecutive detection period of more than or equal to a preset number of times, the amplitude offset of the same specific harmonic in the current state of the hybrid power device inverter power supply is greater than the determination threshold of the corresponding harmonic amplitude offset, or if the total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state is greater than the determination threshold of the total harmonic distortion rate offset, it is determined that the hybrid power device inverter power supply has an open-circuit fault in the current state. At this time, if the hybrid power device inverter power supply is in IGBT driving mode, it can be further determined that the Si IGBT has an open-circuit fault in the current state; if the hybrid power device inverter power supply is in MOSFET driving mode, it can be further determined that the SiC MOSFET has an open-circuit fault in the current state.
[0036] In one exemplary embodiment of this application, by diagnosing Si IGBT open-circuit faults when the hybrid power device inverter power supply is in the IGBT drive mode where Si IGBT is turned on first and then turned off, and diagnosing SiC MOSFET open-circuit faults when the hybrid power device inverter power supply is in the MOSFET drive mode where SiC MOSFET is turned on first and then turned off, it is possible to make the open-circuit faults of different devices exhibit distinguishable harmonic offset characteristics.
[0037] In one exemplary embodiment of this application, setting the driving mode of the hybrid power device inverter includes: acquiring the output current of the hybrid power device inverter in the current state; when the acquired output current of the hybrid power device inverter in the current state is less than a current threshold, setting the driving mode of the hybrid power device inverter to IGBT driving mode; and when the acquired output current of the hybrid power device inverter in the current state is greater than or equal to the current threshold, setting the driving mode of the hybrid power device inverter to MOSFET driving mode. In other words, when the output current of the hybrid power device inverter is in the low current range (less than the current threshold), the inverter is set to IGBT drive mode where the Si IGBT is turned on first and then turned off. The Si IGBT dominates the conduction process in the low current range to enhance the harmonic response to Si IGBT open-circuit faults. When the output current of the hybrid power device inverter is in the high current range (greater than or equal to the current threshold), the inverter is set to MOSFET drive mode where the SiC MOSFET is turned on first and then turned off. The SiC MOSFET dominates the conduction process in the high current range to enhance the harmonic response to SiC MOSFET open-circuit faults. This way, by maximizing the harmonic offset characteristics of Si IGBTs and SiC MOSFETs when they are open-circuited in their dominant ranges, the distinguishable identification of Si IGBT and SiC MOSFET open-circuit faults is achieved.
[0038] In one exemplary embodiment of this application, the determination thresholds for the amplitude offset of each harmonic and the total harmonic distortion rate offset can be set separately under the driving modes (MOSFET driving mode and IGBT driving mode) corresponding to different current ranges. That is, the determination thresholds for the amplitude offset of each harmonic and the total harmonic distortion rate offset can be different under the driving modes corresponding to different current ranges, so as to ensure the predictability and repeatability of fault type diagnosis. This application does not impose any restrictions on this.
[0039] In an exemplary embodiment of this application, based on the harmonic amplitudes and total harmonic distortion (THD) of the hybrid power device inverter power supply in the current state and normal state, the offsets of the harmonic amplitudes and THD of the hybrid power device inverter power supply in the current state are obtained, including: obtaining the offsets of the harmonic amplitudes and THD of the hybrid power device inverter power supply in the current state using formulas (1) and (2), respectively: (1) (2) in, This indicates the state of the hybrid power device inverter power supply in the current state. Second harmonic amplitude offset This indicates the state of the hybrid power device inverter power supply in the current state. Second harmonic amplitude This indicates the first state of the hybrid power device inverter power supply under normal conditions. Second harmonic amplitude This represents the total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state. This represents the total harmonic distortion (THD) of the hybrid power device inverter power supply in its current state. It represents the total harmonic distortion rate of a hybrid power device inverter power supply under normal conditions.
[0040] In one exemplary embodiment of this application, the hybrid power device inverter power supply includes multiple operating conditions, including but not limited to no-load, load-bearing, grid-connected, and off-grid operating conditions. When the hybrid power device inverter power supply includes multiple operating conditions, in the step of obtaining the harmonic amplitude offset and total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state, the harmonic amplitude offset and total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state under each operating condition are obtained based on the harmonic amplitude and total harmonic distortion rate of the hybrid power device inverter power supply in the current state under each operating condition and the normal state under the corresponding operating condition.
[0041] In an exemplary embodiment of this application, based on the harmonic amplitude and total harmonic distortion (THD) of the hybrid power device inverter power supply in the current state and normal state, the offset of the harmonic amplitude and THD of the hybrid power device inverter power supply in the current state are obtained, including: obtaining the offset of the harmonic amplitude and THD of the hybrid power device inverter power supply in the current state under different operating conditions using formulas (3) and (4), respectively: (3) (4) in, Indicates the hybrid power device inverter power supply in the first... The current state under the various operating conditions Second harmonic amplitude offset Indicates the hybrid power device inverter power supply in the first... The current state under the various operating conditions Second harmonic amplitude Indicates the hybrid power device inverter power supply in the first... The first normal state under certain operating conditions Second harmonic amplitude Indicates the hybrid power device inverter power supply in the first... Total harmonic distortion rate offset under various operating conditions in the current state. Indicates the hybrid power device inverter power supply in the first... Total harmonic distortion (THD) under the current operating conditions Indicates the hybrid power device inverter power supply in the first... Total harmonic distortion rate under normal operating conditions.
[0042] In this way, by using the normalization method of the above formulas (3) and (4) to process the amplitude offset of each harmonic and the total harmonic distortion rate offset across operating conditions, the differences in harmonic references (i.e., the judgment thresholds of amplitude offset of each harmonic and total harmonic distortion rate offset) under different operating conditions can be eliminated.
[0043] In an exemplary embodiment of this application, the threshold values for determining the amplitude offset of the same harmonic under different operating conditions of the hybrid power device inverter are equal, and the threshold values for determining the total harmonic distortion rate offset of the hybrid power device inverter under different operating conditions are equal. Exemplarily, through the above-described normalization process, it is possible to set the threshold values for determining the amplitude offset of the same harmonic under different operating conditions and the threshold values for determining the total harmonic distortion rate offset of the hybrid power device inverter under different operating conditions to be equal. This avoids the need to set different threshold values for determining the amplitude offset of each harmonic and the total harmonic distortion rate offset separately for each operating condition, improves diagnostic efficiency, and maintains the comparability of diagnostic features between different operating conditions. For example, the determination thresholds for the same harmonic amplitude offset under different operating conditions and the determination thresholds for the total harmonic distortion rate offset under different operating conditions of the hybrid power device inverter power supply are equal, which means that the determination thresholds for the same harmonic amplitude offset and the determination thresholds for the total harmonic distortion rate offset are equal under different operating conditions in the same driving mode.
[0044] In one exemplary embodiment of this application, the first The threshold for determining the amplitude offset of the subharmonic is expressed as follows: The threshold for determining total harmonic distortion is expressed as: ,Will (or )and Compare and (or )and A comparison is made to diagnose whether an open-circuit fault exists in the hybrid power device inverter power supply. Furthermore, based on the driving mode of the hybrid power device inverter power supply, an open-circuit fault is diagnosed in the Si IGBT or SiC MOSFET within the hybrid power device inverter power supply.
[0045] This concludes the description of the key steps of the open-circuit fault diagnosis method for hybrid power device inverter power supplies of this application. The complete open-circuit fault diagnosis method for hybrid power device inverter power supplies may also include other steps, which will not be elaborated here. It is worth mentioning that the order of the above steps can be adjusted without conflict.
[0046] In summary, the open-circuit fault diagnosis method for hybrid power device inverters of this application acquires the output voltage or current of the hybrid power device inverter in its current state, performs frequency domain analysis on the output voltage or current in the current state to obtain the amplitude of each harmonic and the total harmonic distortion (THD) of the hybrid power device inverter in the current state, and combines the obtained amplitude of each harmonic and THD of the hybrid power device inverter in the normal state to obtain the amplitude offset of each harmonic and the THD offset of the hybrid power device inverter in the current state. The method then compares the amplitude offset of each harmonic in the current state with the corresponding threshold values for the amplitude offset of the harmonic, and compares the THD offset of the hybrid power device inverter in the current state with the threshold values for the THD offset of the THD offset, and determines whether an open-circuit fault exists in the hybrid power device inverter in the current state based on the comparison results. This method can efficiently and accurately diagnose whether an open-circuit fault exists in a hybrid power device inverter.
[0047] This application embodiment also provides an open-circuit fault diagnosis device for a hybrid power device inverter power supply, the hybrid power device inverter power supply including parallel Si IGBTs and SiC MOSFETs, the open-circuit fault diagnosis device for the hybrid power device inverter power supply including a data acquisition module, a frequency domain analysis module, a harmonic feature extraction module, and a fault determination module, wherein: The data acquisition module is used to: acquire the output voltage or output current of the hybrid power device inverter power supply in its current state; The frequency domain analysis module is used to: perform frequency domain analysis on the output voltage or output current of the hybrid power device inverter power supply in the current state, obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the current state, and obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the normal state. The harmonic feature extraction module is used to: obtain the harmonic amplitude offset and total harmonic distortion offset of the hybrid power device inverter power supply in the current state based on the amplitude of each harmonic and the total harmonic distortion rate in the current state and the normal state. The fault determination module is used to: compare the amplitude offset of each harmonic of the hybrid power device inverter in the current state with the determination threshold of the corresponding harmonic amplitude offset, and compare the total harmonic distortion rate offset of the hybrid power device inverter in the current state with the determination threshold of the total harmonic distortion rate offset. If, within a consecutive detection period of more than or equal to a preset number of times, the amplitude offset of the same specific harmonic of the hybrid power device inverter in the current state is greater than the determination threshold of the corresponding harmonic amplitude offset, or if the total harmonic distortion rate offset of the hybrid power device inverter in the current state is greater than the determination threshold of the total harmonic distortion rate offset, it is determined that there is an open circuit fault in the hybrid power device inverter in the current state.
[0048] In one exemplary embodiment of this application, the open-circuit fault diagnosis device for hybrid power device inverter power supplies can be used to implement the open-circuit fault diagnosis method for hybrid power device inverter power supplies described above.
[0049] In an exemplary embodiment of this application, the open-circuit fault diagnosis device for a hybrid power device inverter further includes a drive mode setting module. The acquisition module is used to acquire the output current of the hybrid power device inverter in its current state. The drive mode setting module is used to: set the drive mode of the hybrid power device inverter to IGBT drive mode when the acquired output current is less than a current threshold; and set the drive mode of the hybrid power device inverter to MOSFET drive mode when the acquired output current is greater than or equal to the current threshold. It is worth noting that the acquisition module's use to acquire the output voltage of the hybrid power device inverter in its current state does not mean that the acquisition module is limited to acquiring only the output current of the hybrid power device inverter in its current state; the acquisition module can also be used to acquire the output voltage of the hybrid power device inverter in its current state. Exemplarily, the modules in the open-circuit fault diagnosis device for a hybrid power device inverter are communicatively connected to achieve data transmission. For example, the acquisition module is also used to acquire the output voltage or output current of the hybrid power device inverter power supply under normal conditions; the frequency domain analysis module is used to perform frequency domain analysis on the acquired output voltage or output current of the hybrid power device inverter power supply under normal conditions to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply under normal conditions.
[0050] In one exemplary embodiment of this application, when the hybrid power device inverter power supply is in IGBT drive mode, the Si IGBT turns on first and then turns off compared to the SiC MOSFET; when the hybrid power device inverter power supply is in MOSFET drive mode, the SiC MOSFET turns on first and then turns off compared to the Si IGBT.
[0051] In an exemplary embodiment of this application, when the fault determination module determines that the hybrid power device inverter power supply has an open circuit fault in the current state, the fault determination module is further configured to: identify that the hybrid power device inverter power supply is in IGBT driving mode and determine that the Si IGBT has an open circuit fault in the current state; or, identify that the hybrid power device inverter power supply is in MOSFET driving mode and determine that the SiC MOSFET has an open circuit fault in the current state.
[0052] In an exemplary embodiment of this application, the specific steps and methods for each module in the open-circuit fault diagnosis device for hybrid power device inverter power supply to perform its corresponding function can be referred to the description above, and will not be repeated here.
[0053] In summary, the open-circuit fault diagnosis device for hybrid power device inverters of this application includes a data acquisition module for acquiring the output voltage or output current of the hybrid power device inverter in its current state; a frequency domain analysis module for performing frequency domain analysis on the output voltage or output current of the hybrid power device inverter in its current state to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter in its current state, and for obtaining the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter in its normal state; and a harmonic feature extraction module for extracting the harmonic features of the hybrid power device inverter in its current state. The harmonic amplitudes and total harmonic distortion (THD) of the hybrid power device inverter in the current state are obtained by comparing the harmonic amplitude offsets and THD offsets of the inverter in the previous and normal states. The fault determination module compares the harmonic amplitude offsets of the hybrid power device inverter in the current state with the corresponding harmonic amplitude offset thresholds, and compares the THD offset of the hybrid power device inverter in the current state with the THD offset thresholds. Based on the comparison results, it determines whether an open-circuit fault exists in the hybrid power device inverter in the current state. This allows for efficient and accurate diagnosis of open-circuit faults in hybrid power device inverters.
[0054] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).
[0055] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.
[0056] 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.
[0057] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A method for diagnosing open-circuit faults in a hybrid power device inverter power supply, wherein the hybrid power device inverter power supply comprises Si IGBTs and SiC MOSFETs connected in parallel, characterized in that, The open-circuit fault diagnosis method applied to hybrid power device inverter power supplies includes: Collect the output voltage or output current of the hybrid power device inverter power supply in the current state; Frequency domain analysis is performed on the collected output voltage or output current of the hybrid power device inverter power supply in the current state to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the current state, and the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the normal state are obtained. Based on the harmonic amplitude and total harmonic distortion rate of the hybrid power device inverter power supply in the current state and normal state, the offset of the harmonic amplitude and the offset of the total harmonic distortion rate of the hybrid power device inverter power supply in the current state are obtained. The amplitude offset of each harmonic of the hybrid power device inverter in the current state is compared with the judgment threshold of the corresponding harmonic amplitude offset, and the total harmonic distortion rate offset of the hybrid power device inverter in the current state is compared with the judgment threshold of the total harmonic distortion rate offset. If, within a consecutive detection period of more than or equal to a preset number of times, the amplitude offset of the same specific harmonic of the hybrid power device inverter in the current state is greater than the judgment threshold of the corresponding harmonic amplitude offset, or if the total harmonic distortion rate offset of the hybrid power device inverter in the current state is greater than the judgment threshold of the total harmonic distortion rate offset, it is determined that the hybrid power device inverter has an open circuit fault in the current state.
2. The method for diagnosing open-circuit faults in a hybrid power device inverter power supply according to claim 1, characterized in that, The open-circuit fault diagnosis method applied to hybrid power device inverter power supplies further includes the step of setting the driving mode of the hybrid power device inverter power supply. The driving mode of the hybrid power device inverter power supply includes an IGBT driving mode and a MOSFET driving mode, wherein: when the hybrid power device inverter power supply is in the IGBT driving mode, the Si IGBT is turned on first and then turned off compared to the SiC MOSFET; when the hybrid power device inverter power supply is in the MOSFET driving mode, the SiC MOSFET is turned on first and then turned off compared to the Si IGBT. When it is determined that the hybrid power device inverter power supply has an open circuit fault in the current state, if the hybrid power device inverter power supply is in IGBT drive mode, it is determined that the Si IGBT has an open circuit fault in the current state; if the hybrid power device inverter power supply is in MOSFET drive mode, it is determined that the SiC MOSFET has an open circuit fault in the current state.
3. The method for diagnosing open-circuit faults in a hybrid power device inverter power supply according to claim 2, characterized in that, Setting the drive mode of the inverter power supply for the hybrid power device includes: The output current of the hybrid power device inverter power supply in the current state is collected. When the collected output current of the hybrid power device inverter power supply in the current state is less than the current threshold, the driving mode of the hybrid power device inverter power supply is set to IGBT driving mode. When the collected output current of the hybrid power device inverter power supply in the current state is greater than or equal to the current threshold, the driving mode of the hybrid power device inverter power supply is set to MOSFET driving mode.
4. The method for diagnosing open-circuit faults in a hybrid power device inverter power supply according to claim 1, characterized in that, The offsets of each harmonic amplitude and the total harmonic distortion rate of the hybrid power device inverter power supply in the current state are obtained by formulas (1) and (2), respectively: （1） （2） in, This indicates the state of the hybrid power device inverter power supply in the current state. Second harmonic amplitude offset This indicates the state of the hybrid power device inverter power supply in the current state. Second harmonic amplitude This indicates the first time the hybrid power device inverter power supply is in normal operation. Second harmonic amplitude This represents the total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state. This represents the total harmonic distortion rate of the hybrid power device inverter power supply in the current state. This represents the total harmonic distortion rate of the inverter power supply of the hybrid power device under normal conditions.
5. The method for diagnosing open-circuit faults in a hybrid power device inverter power supply according to claim 1, characterized in that, The hybrid power device inverter power supply includes various operating conditions. The offset of each harmonic amplitude and the offset of the total harmonic distortion rate of the current state of the hybrid power device inverter power supply under different operating conditions are obtained by formulas (3) and (4): （3） （4） in, This indicates that the hybrid power device inverter power supply is in the first... The current state under the various operating conditions Second harmonic amplitude offset This indicates that the hybrid power device inverter power supply is in the first... The current state under the various operating conditions Second harmonic amplitude This indicates that the hybrid power device inverter power supply is in the first... The first normal state under certain operating conditions Second harmonic amplitude This indicates that the hybrid power device inverter power supply is in the first... Total harmonic distortion rate offset under various operating conditions in the current state. This indicates that the hybrid power device inverter power supply is in the first... Total harmonic distortion (THD) under the current operating conditions This indicates that the hybrid power device inverter power supply is in the first... Total harmonic distortion rate under normal operating conditions.
6. The method for diagnosing open-circuit faults in a hybrid power device inverter power supply according to claim 5, characterized in that, The threshold values for determining the amplitude offset of the same harmonic under different operating conditions of the hybrid power device inverter are equal, and the threshold values for determining the total harmonic distortion rate offset of the hybrid power device inverter under different operating conditions are equal.
7. The method for diagnosing open-circuit faults in a hybrid power device inverter power supply according to claim 5, characterized in that, The operating conditions of the hybrid power device inverter include no-load, load, grid-connected, and off-grid.
8. The method for diagnosing open-circuit faults in a hybrid power device inverter power supply according to claim 1, characterized in that, The frequency domain analysis of the output voltage or output current of the hybrid power device inverter power supply in the current state is performed using the Fast Fourier Transform (FFT) or Discrete Fourier Transform (DFT) methods.
9. An open-circuit fault diagnosis device for a hybrid power device inverter power supply, wherein the hybrid power device inverter power supply comprises Si IGBTs and SiC MOSFETs connected in parallel, characterized in that, The open-circuit fault diagnosis device applied to the inverter power supply of hybrid power devices includes a data acquisition module, a frequency domain analysis module, a harmonic feature extraction module, and a fault determination module, wherein: The data acquisition module is used to: acquire the output voltage or output current of the hybrid power device inverter power supply in the current state; The frequency domain analysis module is used to: perform frequency domain analysis on the collected output voltage or output current of the hybrid power device inverter power supply to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the current state, and to obtain the amplitude of each harmonic and the total harmonic distortion rate of the hybrid power device inverter power supply in the normal state. The harmonic feature extraction module is used to: obtain the harmonic amplitude offset and total harmonic distortion offset of the hybrid power device inverter power supply in the current state based on the harmonic amplitude and total harmonic distortion rate of each harmonic in the current state and the normal state. The fault determination module is used to: compare the amplitude offset of each harmonic of the hybrid power device inverter power supply in the current state with the determination threshold of the corresponding harmonic amplitude offset, and compare the total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state with the determination threshold of the total harmonic distortion rate offset. If, within a consecutive detection period of more than or equal to a preset number of times, the amplitude offset of the same specific harmonic of the hybrid power device inverter power supply in the current state is greater than the determination threshold of the corresponding harmonic amplitude offset, or if the total harmonic distortion rate offset of the hybrid power device inverter power supply in the current state is greater than the determination threshold of the total harmonic distortion rate offset, it is determined that the hybrid power device inverter power supply has an open circuit fault in the current state.
10. The open-circuit fault diagnosis device for hybrid power device inverter power supplies according to claim 9, characterized in that, The open-circuit fault diagnosis device applied to the hybrid power device inverter power supply further includes a drive mode setting module. The acquisition module is used to acquire the output current of the hybrid power device inverter power supply in the current state. The drive mode setting module is used to: set the drive mode of the hybrid power device inverter power supply to IGBT drive mode when the acquired output current of the hybrid power device inverter power supply is less than the current threshold, and set the drive mode of the hybrid power device inverter power supply to MOSFET drive mode when the acquired output current of the hybrid power device inverter power supply is greater than or equal to the current threshold. Specifically, when the inverter power supply of the hybrid power device is in IGBT drive mode, the SiIGBT turns on first and then turns off compared to the SiC MOSFET; when the inverter power supply of the hybrid power device is in MOSFET drive mode, the SiC MOSFET turns on first and then turns off compared to the SiIGBT. When the fault determination module determines that the hybrid power device inverter power supply has an open circuit fault in the current state, the fault determination module is further configured to: identify that the hybrid power device inverter power supply is in IGBT drive mode and determine that the Si IGBT has an open circuit fault in the current state; or, identify that the hybrid power device inverter power supply is in MOSFET drive mode and determine that the SiC MOSFET has an open circuit fault in the current state.