Capacitor open-circuit fault detection method, battery system, and storage medium

Abstract

This application relates to the field of capacitor detection technology, and in particular to a method for detecting open-circuit faults in capacitors, a battery system, and a storage medium. This application utilizes existing voltage sensors to sample and acquire bus voltage and candidate voltages of candidate capacitors. A candidate ratio is determined based on the bus voltage, candidate voltages of candidate capacitors, and the target number. A reference ratio is determined based on the target number and a quantity threshold related to the battery system. Finally, based on the candidate ratio and the reference ratio, the fault detection result of the candidate capacitor is obtained. This method enables rapid and accurate detection of open-circuit faults in individual capacitors without requiring complex algorithms, precise current sampling, or any additional hardware. It is low-cost, computationally efficient, places low demands on controller performance, and does not affect other control logic.

Description

Technical Field

[0001] This application relates to the field of capacitor detection technology, and in particular to a capacitor open-circuit fault detection method, a battery system, and a storage medium. Background Technology

[0002] In DC power electronic systems (such as lithium-ion battery systems for truck parking), high-voltage support or absorption capacitor banks need to be connected in parallel between the DC bus (P+ and P-) to stabilize the bus voltage and suppress transient voltage spikes and high-frequency ripples generated by switching device operation. Currently, multiple electrolytic capacitors are connected in series to form a high-voltage capacitor bank as the bus support or absorption capacitor. These high-voltage series capacitor banks operate in harsh environments such as high temperature and continuous vibration, and their reliability directly affects the safety of the entire system.

[0003] In related technologies, the following two methods are mainly used to monitor the health status of such series capacitor banks: 1) Bus voltage monitoring method: By monitoring the ripple amplitude, rise / fall time, or abnormal spikes of the bus voltage, the performance degradation of the capacitor bank can be indirectly inferred; 2) Online capacitor parameter identification method: By inputting a specific frequency excitation signal into the system or using the inherent current and voltage waveforms of the system, the equivalent series resistance or equivalent capacitance of the capacitor bank is estimated online, and the aging status of the capacitor is judged by comparing it with the initial value. The above methods are not specifically designed to detect open circuit faults in individual capacitors, have a time lag, and require complex algorithms and accurate current sampling, resulting in a large computational load, high requirements for controller performance, and potential interference with the control logic of the main system. Summary of the Invention

[0004] One objective of this application is to provide a capacitor open-circuit fault detection method, a battery system, and a storage medium to solve the technical problems in the related art, such as the lag in detecting open-circuit faults of individual capacitors, the large amount of computation, and the potential interference with other control logic.

[0005] In a first aspect, embodiments of this application provide a capacitor open-circuit fault detection method applied to a battery system. The battery system includes a controller and a series capacitor bank connected in parallel to a bus and connected to the controller. The series capacitor bank includes at least two individual capacitors connected in series, and any two individual capacitors have the same capacitance value. The method includes: determining a candidate ratio based on the bus voltage, the candidate voltage of a candidate capacitor, and a target number, wherein the candidate capacitor is any one of the at least two individual capacitors, and the target number is the number of individual capacitors in the series capacitor bank; determining a reference ratio based on the target number and a quantity threshold related to the battery system; and obtaining a fault detection result for the candidate capacitor based on the candidate ratio and the reference ratio.

[0006] In some embodiments, determining the candidate ratio based on the bus voltage, the candidate voltage of the candidate capacitor, and the target number includes: sampling and acquiring the bus voltage and the candidate voltage respectively within the same sampling period; obtaining the voltage ratio based on the ratio of the candidate voltage to the bus voltage; and obtaining the candidate ratio based on the product of the voltage ratio and the target number.

[0007] In some embodiments, the reference ratio includes a first ratio and a second ratio. Determining the reference ratio based on a target quantity and a quantity threshold related to the battery system includes: determining a quantity threshold; obtaining a quantity sum based on the sum of the target quantity and the quantity threshold; obtaining a first ratio based on the ratio of the quantity sum to the target quantity; obtaining a quantity difference based on the difference between the target quantity and the quantity threshold; and obtaining a second ratio based on the ratio of the quantity difference to the target quantity.

[0008] In some embodiments, determining the quantity threshold includes: obtaining a minimum quantity threshold based on the target quantity, the voltage sampling error of the battery system, and the rated tolerance of the individual capacitor; and obtaining the quantity threshold by summing the minimum quantity threshold and a preset safety margin threshold.

[0009] In some embodiments, the minimum quantity threshold is obtained based on the target quantity, the voltage sampling error of the battery system, and the rated tolerance of the individual capacitors, including: obtaining a proportional sum based on the sum of the voltage sampling error and the rated tolerance; obtaining a theoretical minimum threshold based on the product of the proportional sum and the target quantity; and rounding the theoretical minimum threshold up to obtain the minimum quantity threshold.

[0010] In some embodiments, obtaining a fault detection result for a candidate capacitor based on a candidate ratio and a reference ratio includes: in response to a candidate ratio satisfying a first target condition, timing a first duration for which the candidate ratio satisfies the first target condition, wherein the first target condition is greater than a first ratio or less than a second ratio; in response to a first duration being greater than or equal to a preset fault confirmation duration, determining a first fault result as a fault detection result, wherein the first fault result is used to characterize an open-circuit fault in a single capacitor; or, in response to a candidate ratio not satisfying the first target condition, or a candidate ratio satisfying the first target condition and the first duration being less than the fault confirmation duration, determining a second fault result as a fault detection result, wherein the second fault result is used to characterize no open-circuit fault in a single capacitor.

[0011] In some embodiments, the detection method further includes: acquiring multiple candidate ratios within a target time period, wherein the target time period is any time period during which the battery system is in normal condition; calculating the mean of the multiple candidate ratios to obtain the ratio mean; calculating the standard deviation of the multiple candidate ratios based on the ratio mean and the multiple candidate ratios to obtain the ratio standard deviation; obtaining a reference fault threshold based on the ratio mean, the ratio standard deviation, and a preset confidence coefficient; determining the measured ratio based on the bus voltage, the measured voltage of the candidate capacitors, and the target number, wherein the measured voltage is the voltage of the candidate capacitors during the actual fault detection process; and obtaining the fault detection result of the candidate capacitors based on the measured ratio and the reference fault threshold.

[0012] In some embodiments, the reference fault threshold includes a first fault threshold and a second fault threshold. The reference fault threshold is obtained based on the ratio mean, the ratio standard deviation, and a preset confidence coefficient, including: obtaining a standard deviation confidence value based on the product of the confidence coefficient and the ratio standard deviation; obtaining a first fault threshold based on the sum of the ratio mean and the standard deviation confidence value; and obtaining a second fault threshold based on the difference between the ratio mean and the standard deviation confidence value.

[0013] In some embodiments, the reference fault threshold includes a first fault threshold and a second fault threshold. Based on the measured ratio and the reference fault threshold, the fault detection result of the candidate capacitor is obtained, including: in response to the measured ratio meeting a second target condition, timing is used to obtain a second duration for which the measured ratio meets the second target condition, the second target condition being greater than the first fault threshold or less than the second fault threshold; in response to the second duration being greater than or equal to a preset fault confirmation duration, a first fault result is determined as the fault detection result, the first fault result being used to characterize the occurrence of a single-cell capacitor open-circuit fault; or, in response to the measured ratio not meeting the second target condition, or the measured ratio meeting the second target condition and the second duration being less than the fault confirmation duration, a second fault result is determined as the fault detection result, the second fault result being used to characterize the occurrence of a single-cell capacitor open-circuit fault.

[0014] In a second aspect, embodiments of this application provide a battery system, including a controller comprising a first voltage detection module, a second voltage detection module, and an execution unit; a series capacitor bank connected in parallel to a bus and connected to the controller, the series capacitor bank comprising at least two individual capacitors connected in series; the first voltage detection module is used to detect the bus voltage, the second voltage detection module is used to detect the voltage of any individual capacitor in the series capacitor bank, and the execution unit receives voltage signals fed back by the first voltage detection module and the second voltage detection module and is used to execute the capacitor open circuit fault detection method provided in the first aspect.

[0015] In a third aspect, embodiments of this application provide a computer-readable storage medium storing computer program instructions that, when executed by a processor, cause the processor to perform the capacitor open-circuit fault detection method provided in the first aspect.

[0016] The embodiments of this application have the following beneficial effects: Unlike related technologies, the embodiments of this application utilize existing voltage sensors to sample and obtain the bus voltage and candidate voltages of candidate capacitors, and determine the candidate ratio based on the bus voltage, candidate voltages of candidate capacitors, and target quantity. A reference ratio is determined based on the target quantity and quantity thresholds related to the battery system. Finally, based on the candidate ratio and reference ratio, the fault detection result of the candidate capacitor is obtained. In this way, the open circuit fault of a single capacitor can be detected quickly and accurately, without the need for complex algorithms, precise current sampling, or any additional hardware. It has low cost, low computational load, low requirements for controller performance, and will not affect other control logic. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the accompanying drawings used in the description of the related technologies or embodiments will be briefly introduced below. Obviously, the drawings described below only show some embodiments of this application and should not be considered as limiting the scope of protection. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 These are schematic diagrams of the battery system provided in some embodiments of this application;

[0019] Figure 2A This is a schematic diagram of the circuit structure of a battery system provided in some embodiments of this application;

[0020] Figure 2B This is a schematic diagram of the circuit structure of a battery system provided in some other embodiments of this application;

[0021] Figure 3 This is a schematic diagram of the controller structure provided in some embodiments of this application;

[0022] Figure 4 This is a flowchart illustrating the capacitor open-circuit fault detection method in some embodiments of this application;

[0023] Figure 5 This is a schematic diagram illustrating the changes in the bus voltage of the battery system in some embodiments of this application;

[0024] Figure 6 This is a flowchart illustrating a capacitor open-circuit fault detection method provided in other embodiments of this application. Detailed Implementation

[0025] To make the objectives and advantages of the embodiments of this application more readily understood, 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 a part of the embodiments of this application, and not all of them. The detailed description of the embodiments of this application in the accompanying drawings is not intended to limit the scope of protection claimed by this application, but only represents selected embodiments of this application. 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.

[0026] It should be noted that, unless there is a conflict, the various technical features involved in the embodiments of this application described below can be combined with each other, and all are within the protection scope of this application. Furthermore, although functional modules are divided in the device or structural schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. In addition, the terms "first," "second," "third," and other similar expressions used herein do not limit the data or execution order, but are only for illustrative purposes and to distinguish identical or similar items with substantially the same function and effect, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features.

[0027] Unless otherwise defined, the technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. It should be understood that the term "and / or" as used in this specification includes any and all combinations of one or more of the listed items.

[0028] In DC power electronic systems (such as lithium-ion battery systems for truck parking), high-voltage support or absorption capacitor banks need to be connected in parallel between the DC bus (P+ and P-) to stabilize the bus voltage and suppress transient voltage spikes and high-frequency ripples generated by switching device operation. Currently, multiple electrolytic capacitors are connected in series to form a high-voltage capacitor bank as the bus support or absorption capacitor to suppress bus voltage spikes and ripples. These high-voltage series capacitor banks operate in harsh environments such as high temperature and continuous vibration, and their reliability directly affects the safety of the entire system.

[0029] In related technologies, the following two methods are mainly used to monitor the health status of such series capacitor banks.

[0030] 1) Bus voltage monitoring method: By monitoring the ripple amplitude, rise / fall time, or abnormal spikes in the bus voltage, the performance degradation of the capacitor bank can be indirectly inferred (mainly for a decrease in capacitance). For example, when the peak value of the bus ripple voltage exceeds a preset threshold, it indicates that the capacitor may be aging or failing.

[0031] 2) Online capacitor parameter identification method: By inputting a specific frequency excitation signal into the system or using the inherent current and voltage waveforms of the system, the equivalent series resistance or equivalent capacitance of the capacitor bank is estimated online, and the aging state of the capacitor is determined by comparing it with the initial value.

[0032] The above methods have at least the following drawbacks: 1. Lag: The above monitoring methods are mainly for capacitor aging (manifested as capacitance decrease, increase in equivalent series resistance (ESR)) or short-circuit faults. When an open-circuit fault occurs in a single capacitor in a series capacitor bank, the entire series capacitor bank circuit is not completely interrupted. The bus voltage may remain relatively stable due to system regulation, and its ripple characteristics change less significantly than when capacitance decreases, making it difficult for traditional methods to directly and quickly detect open-circuit faults in single capacitors. 2. Intrusiveness and complexity: Online capacitor parameter identification methods require complex algorithms (such as least squares method, Kalman filtering, etc.) and accurate current sampling, resulting in a large computational load, high requirements for controller performance, and potential interference with the control logic of the main system. 3. Additional hardware configuration: Some monitoring schemes may require additional current sensors or voltage sampling points, increasing system cost and hardware complexity. 4. Susceptibility to operating condition interference: Bus voltage monitoring methods are susceptible to changes in load, power fluctuations, and other operating conditions, making it difficult to set accurate judgment thresholds and easily leading to false alarms or missed alarms.

[0033] Open circuit in a single capacitor is a frequent and extremely dangerous fault in series capacitor banks. Due to the harsh operating environment of the capacitor bank (such as continuous vibration and drastic temperature changes) and the aging of the capacitors themselves (such as internal connection breakage and thermal fatigue of solder joints), individual capacitors in the capacitor bank may experience open circuit faults. In related technologies, traditional bus voltage or current sensors are insufficient to directly detect open circuit faults in individual capacitors, creating a hidden safety hazard and posing a significant safety risk to power electronic systems.

[0034] In view of this, embodiments of this application provide a capacitor open-circuit fault detection method. By using existing voltage sensors to sample and obtain the bus voltage and candidate voltages of candidate capacitors, a candidate ratio is determined based on the bus voltage, candidate voltages of candidate capacitors, and target quantity. A reference ratio is determined based on the target quantity and a quantity threshold related to the battery system. Finally, based on the candidate ratio and the reference ratio, the fault detection result of the candidate capacitor is obtained. In this way, the open-circuit fault of a single capacitor can be detected quickly and accurately without the need for complex algorithms, precise current sampling, or any additional hardware. It is low in cost, has low computational load, low requirements for controller performance, and does not affect other control logic.

[0035] Please see Figure 1 , Figure 1 The schematic diagram illustrates the structure of a battery system provided in some embodiments of this application.

[0036] like Figure 1 As shown, the battery system 1000 includes a controller 100, a series capacitor bank 200, a battery pack 300, and a switch module 400. The series capacitor bank 200 includes at least two individual capacitors connected in series, meaning at least two individual capacitors are connected in series. The at least two individual capacitors include individual capacitors C1, C2, ..., and CN, for a total of N individual capacitors, where N is an integer greater than or equal to 2. Any two individual capacitors in the series capacitor bank 200 have the same capacitance value; that is, each capacitor in individual capacitors C1, C2, ..., and CN has the same capacitance value. It can be understood that due to factors such as manufacturing process and usage conditions, if the difference in capacitance value between any two individual capacitors is within the allowable capacitance error (e.g., 10mF), the two individual capacitors are considered to have the same capacitance value.

[0037] Please see Figure 1 , Figure 2A and Figure 2B Battery pack 300 is connected to electrical equipment via bus 10. Figure 1 (Not shown in the diagram) Power supply, wherein the series capacitor bank 200 is connected in parallel to the bus 10, and the controller 100 includes a first voltage detection module 101, a second voltage detection module 102 and an execution unit 103.

[0038] For example, the switch module 400 connects the battery pack 300 and the electrical device 500. The switch module 400 is used to connect or disconnect the discharge circuit of the power supply from the battery pack 300 to the electrical device 500. The first voltage detection module 101 is used to detect the bus voltage. (i.e., the voltage of bus 10), the second voltage detection module 102 is used to detect the voltage across any single capacitor in the series capacitor bank 200. The execution unit 103 is connected to the first voltage detection module 101, the second voltage detection module 102, and the switch module 400. The execution unit 103 is used to receive the bus voltage detected by the first voltage detection module 101. The voltage across any single capacitor detected by the second voltage detection module 102 is used to execute the following capacitor open circuit fault detection method.

[0039] In some embodiments, the switching module 400 may be a switching transistor Q1. The control terminal of the switching transistor Q1 is connected to the execution unit 103, and the first and second terminals of the switching transistor Q1 are respectively connected to the battery pack 300 and the electrical device 500. When the execution unit 103 detects an open circuit in the series capacitor bank 200, it feeds back a turn-off signal to the control terminal of the switching transistor Q1 to turn off the switching transistor Q1, thereby disconnecting the discharge circuit between the battery pack 300 and the electrical device 500.

[0040] In one specific embodiment, the switch Q1 can be a MOSFET, the gate G of the switch Q1 is connected to the execution unit 103, the source S of the switch Q1 is connected to the battery pack 300, and the drain D of the switch Q1 is connected to the electrical device 500.

[0041] In some embodiments, the first voltage detection module 101 and the second voltage detection module 102 can be any existing voltage detection circuit, which can be, but is not limited to, a voltage detection circuit composed of resistors. When the controller 100 is an MCU (Microcontroller Unit), the first voltage detection module 101 and the second voltage detection module 102 can be the MCU's own ADC detection channels, and the execution unit 103 is the core computing unit of the MCU.

[0042] For example, electrical equipment 500 includes, but is not limited to, household appliances (such as induction cookers, microwave ovens, and hair dryers), office equipment (such as printers, copiers, projectors, desktop computers, and laptops), and industrial equipment (such as electric motors, water pumps, fans, and transformers).

[0043] In this embodiment, the controller 100 detects and acquires the bus voltage and the candidate voltage of the candidate capacitor (i.e., the single-cell capacitor CN). Based on the bus voltage, the candidate voltage of the single-cell capacitor CN, and the target number, a candidate ratio is determined. The target number is the number of single-cell capacitors in the series capacitor bank 200. Based on the target number and a quantity threshold related to the battery system 1000, a reference ratio is determined. Finally, based on the candidate ratio and the reference ratio, the fault detection result of the candidate capacitor is obtained. In this way, without adding any additional hardware, it can detect open circuit faults of single-cell capacitors in a low-cost, fast, accurate, and non-invasive manner.

[0044] It should be understood that Figures 1 to 2B The structure of the battery system 1000 is only schematically illustrated and does not limit the structure, type, or number of battery systems and their components in other embodiments. Battery systems and their components in other embodiments may also include more... Figures 1 to 2B The structure shown has more or fewer components, or has the same as Figures 1 to 2B The diagram shows different configurations of the structure.

[0045] To facilitate understanding of the capacitor open-circuit fault detection method provided in the embodiments of this application, the controller provided in the embodiments of this application will be described in detail.

[0046] Please see Figure 3 , Figure 3 A schematic diagram of the controller structure in a battery system provided in some embodiments of this application is shown.

[0047] like Figure 3 As shown, the controller 100 includes at least one processor 110 and at least one memory 120 connected in communication, wherein, Figure 3 Taking a bus system 130, a processor 110, and a memory 120 as an example, the various components of the controller 100 are coupled together through the bus system 130, which is used to realize the connection and communication between the various components. It is easy to understand that the bus system 130 may include, in addition to the data bus, a power bus, a control bus, and a status signal bus, etc. However, for the sake of clarity and brevity, in... Figure 3 The general labels all buses as Bus System 130. This is understandable. Figure 3 The structures shown in the embodiments are merely illustrative and do not limit the structure of the controller described above. For example, the controller may also include components such as... Figure 3 The structure shown has more or fewer components, or has the same as Figure 3 The diagram shows different configurations of the structure.

[0048] For example, processor 110 is configured to provide computational and control capabilities to support controller 100 in executing corresponding business logic and functions. For instance, it supports the execution unit 103 of controller 100 in executing the capacitor open-circuit fault detection method provided in this application embodiment, or in executing steps in any possible implementation of the capacitor open-circuit fault detection method provided in this application embodiment. It is understood that processor 110 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc., and can also be a digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0049] The memory 120, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, instructions, and modules, such as the program, instructions, and modules corresponding to the capacitor open-circuit fault detection method in the embodiments of this application. In some embodiments, the memory 120 may include a program storage area and a data storage area. The program storage area stores the operating system and application programs required for at least one function, while the data storage area stores data created according to the use of the processor 110. The processor 110 executes various functional applications and data processing of the controller 100 by running the non-transitory software programs, instructions, and modules stored in the memory 120, thereby implementing the capacitor open-circuit fault detection method provided in the embodiments of this application, or executing the steps in any possible implementation of the capacitor open-circuit fault detection method provided in the embodiments of this application. In some embodiments, the memory 120 may include high-speed random access memory and may also include non-transitory memory. For example, at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 120 may also include memory remotely located relative to the processor 110, and these remotely located memories may be connected to the processor 110 via a communication network. Understandably, examples of the aforementioned communication networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0050] As can be understood from the above, the entity implementing the capacitor open-circuit fault detection method provided in this application embodiment can be any suitable type of controller with certain computing and control capabilities, such as the controller 100 described above. In some feasible implementations, the capacitor open-circuit fault detection method provided in this application embodiment can be implemented by a processor executing computer program instructions stored in memory.

[0051] The following will describe in detail the capacitor open-circuit fault detection method provided in this application embodiment, with reference to the exemplary application and implementation of the controller provided in the embodiments of this application.

[0052] It is understood that the capacitor open-circuit fault detection method provided in this application embodiment can be applied to the above-mentioned controller (e.g., controller 100). Specifically, the execution subject of the capacitor open-circuit fault detection method is one or at least two processors of the controller.

[0053] See Figure 4 As shown, in this embodiment of the application, the detection of open circuit faults in a single capacitor is achieved through steps S41 to S43.

[0054] Step S41: Determine the candidate ratio based on the bus voltage, the candidate voltage of the candidate capacitor, and the target number.

[0055] In this embodiment, the candidate capacitor is any one of at least two individual capacitors. The target quantity is the number of individual capacitors in the series capacitor group. This embodiment obtains the number of individual capacitors in the series capacitor group as the target quantity. The target quantity is stored in any suitable storage medium such as the controller's local storage, a server, or the cloud. This embodiment obtains the target quantity from the controller's local storage, a server, or the cloud.

[0056] Specifically, in this application embodiment, a voltage detection device or circuit equipped on the controller itself is used to sample and obtain the bus voltage and the voltage across the candidate capacitor (i.e., the candidate voltage). For example, the voltage detection device includes a first voltage detection module and a second voltage detection module. The first voltage detection module is used to sample and obtain the bus voltage, and the second voltage detection module is used to sample and obtain the candidate voltage of the candidate capacitor.

[0057] In some embodiments, after sampling and acquiring the bus voltage and the candidate voltage of the candidate capacitor, the bus voltage and the candidate voltage are calibrated according to preset voltage calibration parameters to obtain corresponding first voltage and second voltage. The ratio of the second voltage to the first voltage is multiplied by the target number to obtain the candidate ratio. The voltage calibration parameters include calibration coefficient values ​​and calibration reference values. The calibration of the bus voltage and the candidate voltage according to the preset voltage calibration parameters includes: adding the product of the bus voltage and the calibration coefficient value to the calibration reference value to obtain the first voltage; and adding the product of the candidate voltage and the calibration coefficient value to the calibration reference value to obtain the second voltage.

[0058] In some other embodiments, after sampling and acquiring the bus voltage and the candidate voltage of the candidate capacitor, the bus voltage and the candidate voltage are filtered respectively (e.g., first-order low-pass filtering or moving average filtering) to obtain the corresponding first voltage and second voltage. The ratio of the second voltage to the first voltage is multiplied by the target number to obtain the candidate ratio.

[0059] Of course, any other suitable method or approach can be used to determine the candidate ratio based on the bus voltage, the candidate voltage of the candidate capacitor, and the target number. This application embodiment does not limit this in any way.

[0060] For example, in the embodiments of this application, steps S411 to S413 are used to determine the candidate ratio based on the bus voltage, the candidate voltage of the candidate capacitor, and the target number.

[0061] Step S411: Within the same sampling period, sample and obtain the bus voltage and candidate voltage respectively.

[0062] Step S412: Obtain the voltage ratio based on the ratio of the candidate voltage to the bus voltage.

[0063] Step S413: Obtain candidate ratios based on the product of voltage ratio and target quantity.

[0064] In this embodiment, the sampling period refers to a period of time preset by the engineers according to actual needs.

[0065] In step S411, in the same sampling period, the voltage detection device equipped on the controller itself is used to sample and obtain the bus voltage and the candidate voltage of the candidate capacitor respectively.

[0066] In step S412, based on the candidate voltage With bus voltage The ratio of the voltage ratio is obtained. ,Right now: .

[0067] In step S413, based on the voltage ratio With target quantity The product of these factors yields the candidate ratio. ,Right now: .

[0068] Step S42: Determine the reference ratio based on the target quantity and the quantity thresholds related to the battery system.

[0069] In this embodiment, the quantity threshold refers to a value preset by engineers based on factors such as the battery system's capacitance tolerance, voltage sampling error, and safety margin threshold. The quantity threshold is an integer greater than or equal to 1, for example, a quantity threshold of 1, 2, 3, or 4.

[0070] For example, the quantity threshold is stored in any suitable storage medium such as the controller's local storage, server, or cloud. In this application embodiment, the quantity threshold is obtained from the controller's local storage, server, or cloud.

[0071] In some embodiments, determining a reference ratio based on a target quantity and a quantity threshold related to the battery system includes: dividing the target quantity by the sum of the target quantity and the quantity threshold to obtain a first ratio, and using the difference between the natural number 1 and the first ratio as a reference ratio.

[0072] In some other embodiments, determining a reference ratio based on a target quantity and a quantity threshold related to the battery system includes using the ratio obtained by dividing the sum of the target quantity and the quantity threshold by the difference between the target quantity and the quantity threshold as the reference ratio.

[0073] Of course, any other suitable method or approach can be used to determine the reference ratio based on the target quantity and the quantity threshold related to the battery system. This application embodiment does not limit this in any way.

[0074] For example, in the embodiments of this application, steps S421 to S425 are used to determine a reference ratio based on the target quantity and a quantity threshold related to the battery system.

[0075] Step S421: Determine the quantity threshold.

[0076] In step S421, the engineers pre-determine the quantity threshold based on the battery system's capacitance tolerance, voltage sampling error, and safety margin threshold. and store quantity thresholds It can be stored on the controller's local storage, a server, or any suitable storage medium in the cloud.

[0077] For example, in the embodiments of this application, the determination of the quantity threshold is achieved through steps A1 to A2.

[0078] Step A1: Based on the target quantity, the voltage sampling error of the battery system, and the rated tolerance of the individual capacitor, obtain the minimum quantity threshold.

[0079] Understandable, in the context of In a series capacitor bank consisting of individual capacitors of the same capacitance value connected in series, ideally, the voltage division ratio of each individual capacitor is: (Right now Candidate ratio (Right now The ideal value for ) is 1. However, the voltage sampling error of the battery system (expressed as) ) and the rated tolerance of individual capacitors (expressed as The inherent uneven partial pressure caused by this will collectively lead to a decrease in the candidate ratio. It fluctuates around 1. This application embodiment uses voltage sampling error... and rated tolerance Quantify the candidate ratio in the worst case It may deviate from the maximum permissible deviation range of the ideal value of 1.

[0080] In step A1, the voltage sampling error of the battery system refers to the sum of the sampling error of the bus voltage in the battery system and the sampling error of the candidate voltage of the candidate capacitor. This embodiment of the application uses the datasheet of the sensor and analog-to-digital converter, which records the voltage sampling error, to obtain the voltage sampling error of the battery system. .

[0081] In step A1, this embodiment of the application obtains the rated tolerance of a single capacitor by consulting the capacitor datasheet. Based on the target number Voltage sampling error and rated tolerance Obtain the minimum quantity threshold .

[0082] For example, in the embodiments of this application, steps A11 to A13 are used to obtain the minimum quantity threshold based on the target quantity, the voltage sampling error of the battery system, and the rated tolerance of the individual capacitor.

[0083] Step A11: Obtain the ratio sum based on the sum of voltage sampling error and rated tolerance.

[0084] Step A12: Obtain the theoretical minimum threshold based on the product of the ratio and the target quantity.

[0085] Step A13: Round up the theoretical minimum threshold to obtain the minimum quantity threshold.

[0086] In step A21, based on voltage sampling error With rated tolerance Summing them together gives the ratio and sum value. ,Right now: .

[0087] In step A22, based on proportions and values With target quantity The product of these terms yields the theoretical minimum threshold. ,Right now: .

[0088] In step A23, the theoretical minimum threshold is... Round up to obtain the minimum quantity threshold. .

[0089] Step A2: Obtain the quantity threshold by summing the minimum quantity threshold and the preset safety margin threshold.

[0090] In this embodiment, the safety margin threshold refers to a value preset by engineers based on the engineering environment and experimental data of the battery system. The safety margin threshold is an integer greater than or equal to 1, for example, a safety margin threshold of 1 or 2.

[0091] In step A2, based on the minimum quantity threshold and safety margin threshold Summing the values ​​yields the quantity threshold. ,Right now: .

[0092] The following example illustrates how to determine the quantity threshold. The specific process.

[0093] For example, in a 3140Ah truck parking lithium battery system, 11 individual capacitors with the same capacitance value are connected in series to form a series capacitor bank, wherein the target number Voltage sampling error Rated tolerance Then the ratio and value Theoretical minimum threshold The theoretical minimum threshold Round up to obtain the minimum quantity threshold. Among them, the safety margin threshold Then the quantity threshold .

[0094] Step S422: Obtain the quantity and value based on the sum of the target quantity and the quantity threshold.

[0095] Step S423: Obtain the first ratio based on the ratio of quantity and value to the target quantity.

[0096] Step S424: Obtain the quantity difference based on the difference between the target quantity and the quantity threshold.

[0097] Step S425: Obtain a second ratio based on the ratio of the quantity difference to the target quantity.

[0098] In this embodiment, the reference ratio includes a first ratio and a second ratio.

[0099] In step S422, based on the target quantity With quantity threshold Summing to obtain the quantity and value. ,Right now: .

[0100] In step S423, based on quantity and value With target quantity The ratio of the two values ​​is used to obtain the first ratio. ,Right now: .

[0101] In step S424, based on the target quantity With quantity threshold The difference is used to obtain the quantity difference. ,Right now: .

[0102] In step S425, based on the quantity difference With target quantity The ratio of the two ratios is used to obtain the second ratio. ,Right now: Clearly, the first ratio Greater than the second ratio .

[0103] Step S43: Based on the candidate ratio and the reference ratio, obtain the fault detection results of the candidate capacitor.

[0104] For example, in this embodiment of the application, a candidate ratio is compared with a reference ratio to determine the magnitude relationship between the candidate ratio and the reference ratio. Based on the magnitude relationship between the candidate ratio and the reference ratio, a fault detection result for the candidate capacitor is obtained. Specifically, obtaining the fault detection result for the candidate capacitor based on the magnitude relationship between the candidate ratio and the reference ratio includes: when the candidate ratio is greater than or equal to the reference ratio, it indicates that the candidate capacitor has an open-circuit fault, and a first result indicating an open-circuit fault in a single capacitor is determined as the fault detection result for the candidate capacitor; when the candidate ratio is less than the reference ratio, it indicates that the candidate capacitor has not had an open-circuit fault, and a second result indicating that no open-circuit fault in a single capacitor is determined as the fault detection result for the candidate capacitor.

[0105] For example, in the embodiments of this application, steps S431 to S432 are used to obtain the fault detection result of the candidate capacitor based on the candidate ratio and the reference ratio.

[0106] Step S431: In response to the candidate ratio satisfying the first target condition, time the first duration for which the candidate ratio satisfies the first target condition.

[0107] In this embodiment, the first target condition is greater than a first ratio or less than a second ratio.

[0108] For example, when the candidate ratio satisfies the first objective condition (i.e., the candidate ratio) Greater than the first ratio or less than the second ratio ,Right now: or In this embodiment, the candidate ratio is obtained by using a built-in timer. The first duration to satisfy the first objective condition It is easy to understand that a timer can be a software timer, a hardware timer, or a combination of both.

[0109] Step S432: In response to the first duration being greater than or equal to a preset fault confirmation duration, determine the first fault result as the fault detection result.

[0110] In this embodiment of the application, the first fault result is used to characterize the occurrence of a single-cell capacitor open-circuit fault. That is, when a candidate capacitor has an open-circuit fault, the output fault detection result is the first fault result, which is used to characterize the occurrence of a single-cell capacitor open-circuit fault.

[0111] In this embodiment, the fault confirmation time is a preset time set by engineers based on experimental and empirical data. The duration can be any suitable length, such as 1 second, 2 seconds, or other durations. By controlling the fault confirmation duration, it is used to filter out accidental and transient voltage distortions caused by transient interference, which can significantly reduce or even eliminate false alarms of open circuit faults.

[0112] For example, when the first duration Greater than or equal to fault confirmation time (Right now When the first fault result is determined to be the first fault detection result, it indicates that the candidate capacitor has an open circuit fault. In this embodiment, after determining the first fault result as the fault detection result, the system triggers a fault alarm signal (the fault alarm signal can be any suitable form of signal such as voice or text), and presents the fault alarm signal (for example, broadcasting the fault alarm signal in the form of voice, or displaying the fault alarm signal in the form of text on the display device) to notify engineers or users that a single capacitor open circuit fault has occurred.

[0113] For example, in the embodiment of this application, step S433 is used to obtain the fault detection result of the candidate capacitor based on the candidate ratio and the reference ratio.

[0114] Step S433: In response to the candidate ratio not meeting the first target condition, or the candidate ratio meeting the first target condition and the first duration being less than the fault confirmation duration, determine the second fault result as the fault detection result.

[0115] In this embodiment of the application, the second fault result is used to characterize that no single-cell capacitor open-circuit fault has occurred. That is, when the candidate capacitor does not have an open-circuit fault, the output fault detection result is the second fault result, which is used to characterize that no single-cell capacitor open-circuit fault has occurred.

[0116] For example, when the candidate ratio does not meet the first objective condition (i.e., the candidate ratio) Greater than or equal to the second ratio And less than or equal to the first ratio. ,Right now ), or the candidate ratio satisfies the first objective condition (i.e., the candidate ratio). Greater than the first ratio or less than the second ratio ,Right now: or And the first duration Less than fault confirmation time (Right now If the second fault result is determined to be the fault detection result, then the second fault result is determined to be the fault detection result. In this embodiment of the application, after determining that the second fault result is the fault detection result, the system triggers a notification signal (the notification signal can be any suitable form of signal such as voice or text), and presents the notification signal (for example, broadcasting a notification signal in the form of voice, or displaying a notification signal in the form of text on a display device) to remind engineers or users that no single capacitor open circuit fault has occurred.

[0117] This application embodiment utilizes existing voltage sensors to sample and acquire bus voltage and candidate voltage of candidate capacitors. Based on the bus voltage, candidate voltage of candidate capacitors, and target quantity, a candidate ratio is determined. Based on the target quantity and quantity threshold related to the battery system, a reference ratio is determined. Finally, based on the candidate ratio and reference ratio, the fault detection result of the candidate capacitor is obtained. In this way, the open circuit fault of a single capacitor can be detected quickly and accurately without the need for complex algorithms, precise current sampling, or any additional hardware. It is low in cost, has low computational load, low requirements for controller performance, and does not affect other control logic.

[0118] The following examples illustrate the beneficial effects of the embodiments of this application: Refer to Table 1 and... Figure 5As shown in Table 1, 11 individual capacitors with the same capacitance value are connected in series (i.e., the target number). The candidate ratio of a series capacitor bank under normal conditions and under conditions of single-cell open-circuit fault is... The theoretical and simulation diagrams illustrate the change process. Figure 5 In the diagram, line L51 represents the bus voltage. (Unit: ).

[0119] Table 1:

[0120]

[0121] According to Table 1 and Figure 5 Before time t3: During the period of stable operation of the battery system, regardless of the bus voltage (like Figure 5 How does the curve L51 fluctuate (e.g., due to load changes), and what are the candidate ratios? The voltage consistently fluctuates within a narrow range around the ideal value of 1 (e.g., 0.97-1.03), and the series capacitor bank as a whole closely follows the bus voltage. .

[0122] At time t3: The candidate capacitor (e.g., single capacitor C5) has an open-circuit fault.

[0123] At time t3: the voltage transient caused by circuit parasitic parameters; candidate ratio. A sharp change may occur, at which point the candidate voltage of the candidate capacitor will change. and candidate ratio All deviate from the normal values, as shown in Table 1, candidate voltages Deviation to Candidate ratio Deviation to 0.023.

[0124] After time t3: Candidate voltage Maintain as Unchanged, candidate ratio It remains unchanged at 0.023.

[0125] Combined with Table 1 and Figure 5 It can be seen that an open-circuit fault in a single capacitor will affect the candidate ratio. The fundamental and steady-state deviations occur, and the fixed threshold (i.e., the quantity threshold) set in the embodiments of this application can reliably distinguish between open-circuit faults of individual capacitors and normal numerical fluctuations, intuitively demonstrating the theoretical basis and expected effect of the detection method provided in the embodiments of this application.

[0126] See Figure 6As shown, in some embodiments, the capacitor open-circuit fault detection method provided in this application further includes steps S401 to S406.

[0127] Step S401: Obtain multiple candidate ratios within the target time period.

[0128] Step S402: Calculate the mean of multiple candidate ratios to obtain the ratio mean.

[0129] In this step, the target time period is any time period during which the battery system is in normal condition. The duration of the target time period can be any suitable duration, such as 10s, 15s, or other durations.

[0130] In some embodiments, after the battery system is powered on or undergoes maintenance, candidate ratios are acquired multiple times during any time period in which no single-cell capacitor open-circuit fault occurs. Multiple candidate ratios were obtained. Multiple candidate ratios Forming a large number of samples (e.g., candidate ratios) quantity (number) data sequences .

[0131] This application's embodiments calculate multiple candidate ratios. The mean of the ratios is obtained by taking the mean of the ratios. Ratio mean This represents the candidate ratio under the current specific hardware parameters (such as the actual ratio of the voltage divider resistors and the actual capacitance combination of the capacitors) and operating conditions, assuming no single-cell capacitor open-circuit fault occurs in the battery system. A real, stable central value.

[0132] Step S403: Based on the mean of the ratio and multiple candidate ratios, calculate the standard deviation of the multiple candidate ratios to obtain the standard deviation of the ratio.

[0133] For example, the embodiments of this application use the following formula: Calculate the standard deviation of multiple candidate ratios to obtain the ratio standard deviation. In the formula, The standard deviation of the ratio. For the first candidate ratios , The ratio is the mean. In order to reach a settlement, Candidate ratio The quantity.

[0134] Understandably, the ratio standard deviation The candidate ratio was quantified to account for all random factors, including sensor noise, power supply ripple, load fretting, and digital sampling quantization error, when no single-cell capacitor open-circuit fault occurred in the battery system. The natural fluctuation range.

[0135] Step S404: Obtain the reference fault threshold based on the ratio mean, ratio standard deviation and preset confidence coefficient.

[0136] In this embodiment, engineers pre-set confidence coefficients based on experimental and empirical data, employing the high-confidence principle from statistical engineering. It is understood that, under the assumption that random errors approximately follow a normal distribution, the confidence coefficients... The value can be 5 or 6, that is: or .

[0137] For example, in the embodiments of this application, steps B1 to B3 are used to obtain a reference fault threshold based on the ratio mean, the ratio standard deviation, and a preset confidence coefficient.

[0138] Step B1: Obtain the standard deviation confidence value based on the product of the confidence coefficient and the standard deviation of the ratio.

[0139] Step B2: Obtain the first fault threshold by summing the mean of the ratios and the confidence values ​​of the standard deviations.

[0140] Step B3: Obtain the second fault threshold based on the difference between the mean of the ratio and the confidence value of the standard deviation.

[0141] In this embodiment, the reference fault threshold includes a first fault threshold and a second fault threshold.

[0142] In step B1, based on the confidence coefficient and the standard deviation of the ratio The product of these terms yields the standard deviation confidence value. ,Right now: .

[0143] In step B2, based on the mean of the ratios confidence value of standard deviation Summing the results yields the first fault threshold. ,Right now: .

[0144] In step B3, based on the mean of the ratios confidence value of standard deviation The difference is used to obtain the second fault threshold. ,Right now: Clearly, the first fault threshold... Greater than the second fault threshold .

[0145] Understandably, after sampling is completed, the ratio mean and the standard deviation of the ratio After that, the ratio mean will not be recalculated. and the standard deviation of the ratio The subsequently obtained candidate ratios Compared with the set reference fault threshold (i.e., the first fault threshold) and the second fault threshold The ratios are compared to detect and determine whether a single-cell capacitor open-circuit fault has occurred. In this embodiment, multiple candidate ratios within a target time period are obtained. By calculating the average value and setting a reference fault threshold, the system deviation caused by different voltage divider resistor accuracies can be adapted to improve detection accuracy.

[0146] Step S405: Determine the measured ratio based on the bus voltage, the measured voltage of the candidate capacitors, and the target number.

[0147] The measured voltage is the voltage of the candidate capacitor during the actual fault detection process.

[0148] For example, in the embodiments of this application, the voltage of the candidate capacitor during the actual fault detection process is obtained as the measured voltage within the same sampling period. Obtain bus voltage Then based on the bus voltage Measured voltage of candidate capacitors and target quantity Determine the measured ratio .

[0149] Among them, based on bus voltage Measured voltage of candidate capacitors and target quantity Determine the measured ratio Includes: based on measured voltage With bus voltage The ratio of the two values ​​is used to obtain the benchmark ratio. , that is: Based on the benchmark ratio With target quantity The product of the two values ​​is used to obtain the measured ratio. ,Right now: .

[0150] Step S406: Based on the measured ratio and the reference fault threshold, obtain the fault detection results of the candidate capacitors.

[0151] For example, in this embodiment, the measured ratio is compared with a reference fault threshold to determine the relationship between the measured ratio and the reference fault threshold, and the fault detection result of the candidate capacitor is obtained based on the relationship between the measured ratio and the reference fault threshold. In this embodiment, obtaining the fault detection result of the candidate capacitor based on the relationship between the measured ratio and the reference fault threshold includes: when the measured ratio is greater than or equal to the reference fault threshold, it indicates that the candidate capacitor has an open circuit fault, and the first result representing an open circuit fault in a single capacitor is determined as the fault detection result of the candidate capacitor; when the measured ratio is less than the reference fault threshold, it indicates that the candidate capacitor has not had an open circuit fault, and the second result representing no open circuit fault in a single capacitor is determined as the fault detection result of the candidate capacitor.

[0152] For example, in the embodiments of this application, steps C1 to C2 are used to obtain the fault detection results of the candidate capacitor based on the measured ratio and the reference fault threshold.

[0153] Step C1: In response to the measured ratio satisfying the second target condition, time the duration for which the measured ratio satisfies the second target condition.

[0154] In this embodiment, the second target condition is greater than the first fault threshold or less than the second fault threshold.

[0155] For example, when the measured ratio satisfies the second objective condition (i.e., the measured ratio) Greater than the first fault threshold Or less than the second fault threshold ,Right now: or In this embodiment, the measured ratio is obtained by using a built-in timer. Second duration to satisfy the second objective condition It's easy to understand that a timer can be a software timer, a hardware timer, or a combination of both.

[0156] Step C2: In response to the second duration being greater than or equal to the preset fault confirmation duration, the first fault result is determined as the fault detection result.

[0157] In this embodiment, the first fault result is used to characterize the occurrence of an open-circuit fault in a single capacitor. That is, when a candidate capacitor has an open-circuit fault, the output fault detection result is the first fault result, which is used to characterize the occurrence of an open-circuit fault in a single capacitor.

[0158] For example, when the second duration Greater than or equal to fault confirmation time (Right now When the first fault result is determined to be the first fault detection result, it indicates that the candidate capacitor has an open circuit fault. In this embodiment, after determining the first fault result as the fault detection result, the system triggers a fault alarm signal (the fault alarm signal can be any suitable form of signal such as voice or text), and presents the fault alarm signal (for example, broadcasting the fault alarm signal in the form of voice, or displaying the fault alarm signal in the form of text on the display device) to notify engineers or users that a single capacitor open circuit fault has occurred.

[0159] In some embodiments, this application embodiment achieves the acquisition of fault detection results for candidate capacitors based on measured ratios and reference fault thresholds through step C3.

[0160] Step C3: In response to the measured ratio not meeting the second target condition, or the measured ratio meeting the second target condition and the second duration being less than the fault confirmation duration, determine the second fault result as the fault detection result.

[0161] In this embodiment, the second fault result is used to characterize that no single capacitor open circuit fault has occurred. That is, when the candidate capacitor does not have an open circuit fault, the output fault detection result is the second fault result, which is used to characterize that no single capacitor open circuit fault has occurred.

[0162] For example, when the measured ratio does not meet the second objective condition (i.e., the measured ratio...) Greater than or equal to the second fault threshold And less than or equal to the first fault threshold ,Right now Alternatively, the measured ratio satisfies the second objective condition (i.e., the measured ratio). Greater than the first fault threshold or less than the second fault threshold ,Right now or And the second duration Less than fault confirmation time (Right now If the second fault result is determined to be the fault detection result, then the system triggers a notification signal (the notification signal can be any suitable form of signal such as voice or text) and presents the notification signal (for example, broadcasting a voice notification signal or displaying a text notification signal on a display device) to remind engineers or users that no single capacitor open circuit fault has occurred.

[0163] Overall, the embodiments of this application have at least the following beneficial effects: a), b), c), d), and e).

[0164] a) This application specifically addresses the challenge of detecting open-circuit faults in individual capacitors: Related technologies are insensitive to open-circuit faults in individual capacitors within a series capacitor bank. The embodiments of this application, through analysis... The proportional relationship directly captures the characteristic voltage ratio shift caused by an open-circuit fault in a single capacitor, enabling specialized and sensitive detection of open-circuit faults. For example, when there are 11 single capacitors (i.e., the target number)... When a single capacitor in a series-connected capacitor bank experiences an open-circuit fault, the candidate ratio is... It may jump from the ideal value of 1 to the first ratio. (i.e., quantity threshold) (The same below) or the second ratio Below are the candidate ratios. The change range exceeds 30%, making it very easy to detect. Thus, it is possible to detect open circuit faults in individual capacitors.

[0165] b) Non-invasive and low-cost: The embodiments of this application only utilize the existing voltage detection device or circuit of the battery system to sample and obtain the bus voltage. Candidate voltage of candidate capacitor It requires no additional sensors or changes to the main circuit topology; the detection logic is implemented by software algorithms, resulting in low hardware costs.

[0166] c) High robustness and anti-interference: Due to the use of candidate ratios Instead of using absolute voltage values ​​as the criterion, the embodiments of this application can effectively offset bus voltage caused by power fluctuations and load changes. The impact of overall changes on fault detection results. Simultaneously, the introduction of a delayed confirmation mechanism can filter out false triggers caused by switching noise or transient interference, improving the reliability of fault detection results.

[0167] d) Good generalizability and ease of use: based on , The general criterion formula in this application can be quickly adapted to different target quantities. A series capacitor bank. Engineers only need to determine the target number based on the battery system specifications. and quantity threshold It eliminates the need for complex modeling and parameter tuning, greatly simplifying engineering applications.

[0168] e) Proactive Early Warning and Enhanced System Safety: Embodiments of this application can issue early warnings at an early stage, before secondary disasters (such as power transistor overvoltage breakdown) occur due to the failure of the series capacitor bank. This transforms the maintenance mode from passive "post-fault repair" to proactive "predictive maintenance." The battery system can promptly guide on-site repairs through alarm signals such as indicator lights and voice broadcasts, effectively preventing cascading damage to expensive power devices and significantly improving the availability and lifecycle safety of the battery system.

[0169] This application provides a computer-readable storage medium storing processor-executable computer program instructions. When executed by a processor, the computer program instructions cause the processor to perform steps in any possible implementation of the capacitor open-circuit fault detection method provided in this application.

[0170] In some embodiments, the storage medium may be a flash memory, a hard disk, an optical disk, a register, a magnetic surface memory, a removable disk, a CD-ROM, a random access memory (RAM), a read-only memory (ROM), an electrically programmable ROM, and an electrically erasable programmable ROM, or any other form of storage medium known in the art, or various devices including one or any combination of the above storage media.

[0171] In some embodiments, computer program instructions may take the form of programs, software, software modules, scripts, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as stand-alone programs or as modules, components, subroutines, or other units suitable for use in a computing environment.

[0172] As an example, computer program instructions may, but do not necessarily, correspond to files in a file system, and may be stored as part of a file that holds other programs or data, for example, in one or more scripts in an HTML (Hypertext Markup Language) document, or in a single file dedicated to the program in question, or in multiple collaborative files (e.g., a file that stores one or more modules, subroutines, or code sections).

[0173] As an example, computer program instructions can be deployed to execute on a single computing device (including devices such as smart terminals and servers), or on multiple computing devices located in one location, or on multiple computing devices distributed across multiple locations and interconnected via a communication network. It is readily understood that all or part of the steps of the methods described in the embodiments provided above can be implemented directly using electronic hardware or processor-executable computer program instructions, or a combination of both.

[0174] Those skilled in the art will understand that the embodiments provided in this application are merely illustrative. The order in which the steps in the methods of the embodiments are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The order can be adjusted, merged, and deleted according to actual needs. Modules or sub-modules, units or sub-units in the apparatus or system of the embodiments can be merged, divided, and deleted according to actual needs. For example, the division of units is only a logical functional division, and there may be other division methods in actual implementation. For another example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0175] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, it can be implemented using hardware. Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This computer program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods.

[0176] It should be noted that the above embodiments are for illustrating the technical concept and features of this application, and are intended to enable those skilled in the art to understand the content of this application and implement it accordingly. They should not be construed as limiting the scope of protection of this application. Those skilled in the art can understand that all or part of the processes of the above embodiments can be implemented, modified according to the technical solutions described in the embodiments of this application, or equivalent substitutions can be made to some of the technical features. It is understood that these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and should be considered as equivalent changes and modifications made based on the embodiments of this application, all of which should fall within the scope of the claims of this application.

Claims

1. A method for detecting open-circuit faults in capacitors, applied to a battery system, characterized in that, The battery system includes a controller and a series capacitor bank connected in parallel to the bus and connected to the controller. The series capacitor bank includes at least two individual capacitors connected in series, and any two individual capacitors have the same capacitance value. The method includes: Determining a candidate ratio based on the bus voltage, the candidate voltage of the candidate capacitor, and the target number includes: sampling and acquiring the bus voltage and the candidate voltage respectively within the same sampling period; obtaining a voltage ratio based on the ratio of the candidate voltage to the bus voltage; and obtaining the candidate ratio based on the product of the voltage ratio and the target number; wherein the candidate capacitor is any one of at least two individual capacitors, and the target number is the number of individual capacitors in the series capacitor group; Determining a reference ratio based on the target quantity and a quantity threshold related to the battery system includes: determining the quantity threshold; obtaining a quantity sum based on the sum of the target quantity and the quantity threshold; obtaining a first ratio based on the ratio of the quantity sum to the target quantity; obtaining a quantity difference based on the difference between the target quantity and the quantity threshold; and obtaining a second ratio based on the ratio of the quantity difference to the target quantity. The quantity threshold is a value determined based on the voltage sampling error of the battery system, the rated tolerance of the individual capacitors, and the target quantity. The reference ratio includes the first ratio and the second ratio. Based on the candidate ratio and the reference ratio, the fault detection result of the candidate capacitor is obtained.

2. The detection method according to claim 1, characterized in that, Determining the quantity threshold includes: Based on the target quantity, the voltage sampling error of the battery system, and the rated tolerance of the individual capacitor, a minimum quantity threshold is obtained; The quantity threshold is obtained by summing the minimum quantity threshold and the preset safety margin threshold.

3. The detection method according to claim 2, characterized in that, The process of obtaining the minimum quantity threshold based on the target quantity, the voltage sampling error of the battery system, and the rated tolerance of the individual capacitors includes: The ratio and summation value are obtained by summing the voltage sampling error and the rated tolerance. The theoretical minimum threshold is obtained based on the product of the ratio and the target quantity; The minimum theoretical threshold is rounded up to obtain the minimum quantity threshold.

4. The detection method according to any one of claims 1-3, characterized in that, The step of obtaining the fault detection result of the candidate capacitor based on the candidate ratio and the reference ratio includes: In response to the candidate ratio satisfying a first target condition, a first duration for which the candidate ratio satisfies the first target condition is timed, wherein the first target condition is greater than the first ratio or less than the second ratio. In response to the first duration being greater than or equal to a preset fault confirmation duration, a first fault result is determined as the fault detection result, wherein the first fault result is used to characterize the occurrence of a single-cell capacitor open-circuit fault. or, In response to the candidate ratio not meeting the first target condition, or the candidate ratio meeting the first target condition and the first duration being less than the fault confirmation duration, a second fault result is determined as the fault detection result, and the second fault result is used to characterize that no single-cell capacitor open-circuit fault has occurred.

5. The detection method according to any one of claims 1-3, characterized in that, The detection method further includes: Obtain multiple candidate ratios within a target time period, where the target time period is any time period during which the battery system is in normal condition; Calculate the mean of multiple candidate ratios to obtain the ratio mean; Based on the mean of the ratios and the multiple candidate ratios, the standard deviation of the multiple candidate ratios is calculated to obtain the standard deviation of the ratios; A reference fault threshold is obtained based on the mean of the ratios, the standard deviation of the ratios, and a preset confidence coefficient. Based on the bus voltage, the measured voltage of the candidate capacitors, and the target number, the measured ratio is determined, where the measured voltage is the voltage of the candidate capacitors during the actual fault detection process. Based on the measured ratio and the reference fault threshold, the fault detection result of the candidate capacitor is obtained.

6. The detection method according to claim 5, characterized in that, The reference fault threshold includes a first fault threshold and a second fault threshold. Obtaining the reference fault threshold based on the mean of the ratios, the standard deviation of the ratios, and a preset confidence coefficient includes: The standard deviation confidence value is obtained by multiplying the confidence coefficient by the standard deviation of the ratio. The first fault threshold is obtained by summing the mean of the ratios and the confidence value of the standard deviation. The second fault threshold is obtained based on the difference between the mean of the ratios and the confidence value of the standard deviation.

7. The detection method according to claim 5, characterized in that, The reference fault threshold includes a first fault threshold and a second fault threshold. Obtaining the fault detection result of the candidate capacitor based on the measured ratio and the reference fault threshold includes: In response to the measured ratio satisfying the second target condition, a second duration for which the measured ratio satisfies the second target condition is timed, wherein the second target condition is greater than the first fault threshold or less than the second fault threshold. In response to the second duration being greater than or equal to a preset fault confirmation duration, a first fault result is determined as the fault detection result, wherein the first fault result is used to characterize the occurrence of a single-cell capacitor open-circuit fault. or, In response to the measured ratio not meeting the second target condition, or the measured ratio meeting the second target condition and the second duration being less than the fault confirmation duration, the second fault result is determined as the fault detection result, and the second fault result is used to characterize that no single-cell capacitor open-circuit fault has occurred.

8. A battery system, characterized in that, include: The controller includes a first voltage detection module, a second voltage detection module, and an execution unit; A series capacitor bank is connected in parallel to the bus and connected to the controller. The series capacitor bank includes at least two individual capacitors connected in series. The first voltage detection module is used to detect the bus voltage, and the second voltage detection module is used to detect the voltage of any single capacitor in the series capacitor group. The execution unit receives the voltage signals fed back by the first voltage detection module and the second voltage detection module and uses them to execute the capacitor open circuit fault detection method according to any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions that, when executed by a processor, cause the processor to perform the capacitor open-circuit fault detection method as described in any one of claims 1-7.

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