A diagnostic method, device, and medium for a pre-charging circuit.

Abstract

This application discloses a diagnostic method, device, and medium for a pre-charging circuit. The method includes: outputting an isolated power supply through a pre-set full-bridge resonant circuit to perform isolated charging based on the isolated power supply; alternately turning on multiple full-bridge switches to complete the switching cycle and charging cycle, thereby achieving a voltage step-up for constant current charging; and determining the closing state of the main relay through a pre-set detection circuit. If the main relay is closed, charging is performed and a high-level signal is output; if the main relay is not closed, charging is not possible and a low-level signal is output. This application achieves isolated charging through a full-bridge resonant circuit, improving safety; utilizes the alternating conduction of switches to achieve voltage step-up constant current charging, protecting the battery; and the detection circuit accurately determines the state of the main relay, enhancing system reliability. Furthermore, it is low-cost and highly efficient.

Description

Technical Field

[0001] This application relates to the field of circuit diagnostic technology, and in particular to a diagnostic method, device and medium for a pre-charged circuit. Background Technology

[0002] As automotive safety standards continue to rise, new demands are being placed on the reliability of internal high-voltage components. Particularly within integrated controllers, relay sticking or malfunctions in their closing logic can lead to severe damage, such as burning out the controller's high-voltage link or even causing a fire. Detecting relay engagement and sticking is currently a challenging aspect of relay diagnostics, especially when the controller contains main and negative relays. Typically, the circuit board is located behind the main and negative relays. If these relays fail to close, problems such as floating ground issues can occur in the downstream circuitry, making conventional voltage acquisition methods insufficient for accurate relay engagement diagnosis.

[0003] Currently, common testing methods involve using voltage divider resistors to measure the voltage values ​​at both ends of the relay for diagnosis. Additionally, a resistor is connected in parallel across the relay to eliminate floating ground issues in the downstream circuitry. However, these methods require a large number of voltage divider resistors. Excessive parallel resistors can reduce system insulation performance, and the large number of resistors and measurement circuitry also increases costs. Furthermore, considering the capacitive load at the relay's downstream end, an additional pre-charging circuit is needed, further increasing costs. Summary of the Invention

[0004] To address the aforementioned issues, this application proposes a diagnostic method for a pre-charging circuit, comprising: outputting an isolated power supply through a pre-set full-bridge resonant circuit to perform isolated charging based on the isolated power supply; alternately turning on multiple full-bridge switches to complete the switching cycle and charging cycle, thereby achieving a voltage step increase for constant current charging; determining the closing state of the main relay through a pre-set detection circuit; if the main relay is closed, charging is performed and a high level is output; if the main relay is not closed, charging is not possible and a low level is output.

[0005] In one example, the method further includes: the full-bridge resonant circuit includes an input capacitor C1, full-bridge switches Q1, Q2, Q3, and Q4, an inductor L1, a resonant capacitor Cr, and a detection resistor R1; wherein, the input capacitor C1 is used to stabilize the input voltage; the full-bridge switches alternately conduct under a control signal to form a resonant current path; the resonant unit is composed of inductor L1 and resonant capacitor Cr, generating resonance to achieve energy transfer; the detection resistor R1 is used to detect the primary current of the transformer to determine the status of the main relay.

[0006] In one example, the method further includes: the step-up voltage increase for constant current charging specifically includes: implementing a step-up voltage increase through a rectifier circuit for constant current charging; wherein the rectifier circuit includes rectifier diodes D1, D2, D3, and D4, a charging resistor R2, and a load capacitor C2; the rectifier diodes convert AC power into DC power; the charging resistor R2 and the load capacitor C2 form a charging circuit to achieve a step-up voltage increase according to the charging circuit.

[0007] In one example, the closed state of the main relay is determined by a pre-set detection circuit, which specifically includes: the detection circuit includes operational amplifier U1 and operational amplifier U2; the operational amplifier U2 detects the current value flowing through the detection resistor R1 and converts the current value from a differential signal to a single-ended signal; the converted single-ended signal is transmitted to the operational amplifier U1 for judgment by the operational amplifier U1 to determine the closed state of the main relay.

[0008] In one example, the method further includes: judging the closed state of the main relay based on a preset threshold voltage and the current value flowing through the detection resistor R1; if the current value flowing through R1 does not exceed the current value corresponding to the threshold voltage, it indicates that the main relay KA is normally closed and U1 outputs a high level; if the current value flowing through R1 exceeds the current value corresponding to the threshold voltage, it indicates that the main relay KA is not normally closed and U1 outputs a low level.

[0009] In one example, the method further includes: determining the highest point current value of the primary current flowing through R1 during normal closure, so as to determine the corresponding threshold voltage based on the highest point current value, wherein the expression for the threshold voltage is:

[0010]

[0011] Where Vref is the threshold voltage. This is the highest point current value of the primary current flowing through R1 when it is normally closed, and R1 is the sensing resistor.

[0012] In one example, after the main relay is not closed, the method further includes: triggering a pre-set fault warning mechanism to record the fault occurrence time, fault type and current system status; automatically disconnecting the charging circuit to prevent overcurrent or short circuit caused by relay sticking, and notifying maintenance personnel to perform maintenance tasks.

[0013] In one example, this is applied in a pre-charging circuit, which includes an MCU, a detection circuit, a low-voltage power supply module, a full-bridge resonant circuit, a transformer T1, a rectifier circuit, and a main relay KA. The MCU is used to monitor and regulate the working status of each module, and to interact with each module and transmit commands through control signal lines. The low-voltage power supply module is used to provide a stable low-voltage power supply for the entire circuit. The primary side of the transformer T1 is connected to the output terminal of the full-bridge resonant circuit, and the secondary side of the transformer T1 is connected to the rectifier circuit to achieve electrical isolation between the input and output. The main relay KA is connected in series between the output terminal of the rectifier circuit and the load capacitor C2, and is used as a switch for the charging path.

[0014] On the other hand, this application also proposes a diagnostic device for a pre-charge circuit, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the diagnostic device for the pre-charge circuit to perform: the method described in any of the examples above.

[0015] On the other hand, this application also proposes a non-volatile computer storage medium storing computer-executable instructions, wherein the computer-executable instructions are configured to be the method described in any of the examples above.

[0016] This application utilizes a full-bridge resonant circuit to output isolated power for charging, achieving electrical isolation and improving the safety and stability of the charging process. A detection circuit monitors the main relay status in real time; by comparing the current value with a preset threshold, it accurately determines whether the relay is closed, enhancing system reliability and fault warning capabilities. Through the coordination of the rectifier circuit and charging resistors, a stepped voltage increase is achieved, resulting in a near-constant current charging effect, which helps protect the battery and extend its lifespan. If the main relay is detected as not properly closed, the system immediately triggers a fault warning mechanism, automatically cutting off the charging circuit to prevent overcurrent or short circuits and ensure system safety. The circuit structure of this application is clear, with each module functioning independently yet collaboratively, facilitating maintenance and upgrades. Centralized control by the MCU enhances the system's intelligence level, enabling real-time monitoring and adjustment of the operating status of each module. It saves on additional pre-charging circuits and voltage divider resistors, reducing system cost and complexity while improving reliability and efficiency. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1This is a flowchart illustrating a diagnostic method for a pre-charging circuit according to an embodiment of this application.

[0019] Figure 2 This is a schematic diagram of a pre-charging circuit module in an embodiment of this application;

[0020] Figure 3 This is a detailed schematic diagram of a pre-charging circuit in an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the primary current during normal closure in an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of the primary current during abnormal closure in an embodiment of this application;

[0023] Figure 6 This is a schematic diagram of a diagnostic device for a pre-charging circuit according to an embodiment of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, in order to solve the above problems, this application provides a diagnostic method for a pre-charging circuit, which is applied in a pre-charging circuit, such as... Figure 2 As shown, the circuit includes an MCU, a detection circuit, a low-voltage power supply module, a full-bridge resonant circuit, an isolation transformer, a rectifier circuit, a main relay, and a charging capacitor, among other circuit modules and components. Utilizing the operating characteristics of the full-bridge LLC resonant circuit, it outputs an isolated power supply for isolated charging and judges changes in the output load based on changes in the primary current of the detection transformer, thereby directly diagnosing whether the relay is stuck.

[0027] In one embodiment, such as Figure 3As shown, the low-voltage power supply module BAT_LV is filtered by capacitor C1 and then connected to the H-bridge circuit composed of Q1-Q4. The output of the H-bridge is connected to the primary side of transformer T1 through an LC filter network composed of inductor L1 and resonant capacitor Cr. The output of the transformer secondary side is rectified by a rectifier bridge composed of D1-D4, and then filtered by resistor R2 and capacitor C2 before supplying power to the load. The relay KA controls the on / off state. The MCU forms a control loop through U1 and U2, and the output signal of U2 controls the H-bridge drive.

[0028] The methods include:

[0029] S101. An isolated power supply is output through a pre-set full-bridge resonant circuit to perform isolated charging according to the isolated power supply.

[0030] In the pre-charging circuit, C1 serves as the input capacitor, providing initial energy storage for the circuit; Q1 to Q4 form a full-bridge switching array, achieving energy conversion and transmission through alternating conduction; inductor L1 and resonant capacitor Cr together form a resonant unit, utilizing the resonance principle to improve circuit efficiency; R1 serves as a sensing resistor, connected in series in the circuit to monitor current changes; T1 is a transformer, providing electrical isolation and voltage conversion functions; D1 to D4 form a rectifier diode group, converting AC to DC; R2 is a charging resistor, limiting the charging current to protect the load; KA serves as the main relay, controlling the on / off state of the charging path; and the load capacitor C2 is used to store energy and supply power to subsequent circuits.

[0031] S102. Multiple full-bridge switches are alternately turned on to complete the switching cycle and charging cycle, thereby achieving a step-up voltage increase for constant current charging.

[0032] During the charging process, the two sets of switching transistors Q1 and Q4, and Q2 and Q3, are alternately turned on to complete one complete switching cycle, and two charging cycles are achieved during this period. Specifically, in each half-switching cycle, the primary resonant current flows sequentially through the switching transistors, resonant inductor L1, sensing resistor R1, transformer T1, and load capacitor C2. At the same time, a current is induced on the secondary side of the transformer. This current flows through the freewheeling rectifier diodes, i.e., rectifier diodes D1-D4, charging resistor R2, and main relay KA to the load capacitor C2, charging it and gradually increasing the capacitor voltage by one step, thus completing one step-by-step charging.

[0033] As the switching transistors alternately turn on and off, the voltage across the load capacitor C2 increases in a stepwise manner, achieving a near-constant current charging effect.

[0034] S103. The closed state of the main relay is determined by a pre-set detection circuit. If the main relay is closed, it is charged and outputs a high level; if the main relay is not closed, it cannot be charged and outputs a low level.

[0035] Operational amplifiers U1 and U2 are responsible for signal processing and threshold comparison, respectively. U2 converts the differential signal across the detection resistor R1 into a single-ended signal and transmits it to U1. U1 then determines the state of the main relay KA based on the preset threshold and outputs the corresponding level signal.

[0036] like Figure 4 As shown in the diagram, when the main relay KA is normally closed and can perform normal charging, the current flowing through R1 in one switching cycle is the same as the current flowing through the primary side. The highest current value Iref is taken as the subsequent threshold voltage Vref, where Vref = Iref * R1. Operational amplifier U2 is responsible for detecting the current value across resistor R1. It converts the acquired differential current signal into a single-ended signal and sends it to the threshold judgment module composed of operational amplifier U1. When the main relay KA is normally closed, the signal received by U1 is within the normal range, and its output remains high.

[0037] like Figure 5 As shown in the diagram, when the main relay KA is not properly closed, normal charging cannot be achieved, meaning there is no load after the power supply. In this case, the current flowing through R1 during one switching cycle is the current flowing through the primary side. Operational amplifier U2 is responsible for real-time detection of the current flowing through the detection resistor R1, converting this differential current signal into a single-ended signal, and transmitting it to the threshold judgment circuit composed of operational amplifier U1. When the main relay KA is in an abnormally closed state, the current flowing through R1 will exceed the preset threshold. At this time, the output signal of U1 will turn low, serving as an indication of an abnormal relay status.

[0038] like Figure 6 As shown in the illustration, this application also provides a diagnostic device for a pre-charging circuit, comprising:

[0039] At least one processor; and,

[0040] A memory that is communicatively connected to at least one processor; wherein,

[0041] The memory stores instructions that can be executed by at least one processor to enable a diagnostic device for a pre-charged circuit to perform the method as described in any of the embodiments above.

[0042] This application also provides a non-volatile computer storage medium storing computer-executable instructions, which are configured as described in any of the above embodiments.

[0043] In the 1990s, improvements to a technology could be clearly distinguished as either hardware improvements (e.g., improvements to the circuit structure of diodes, transistors, switches, etc.) or software improvements (improvements to the methodology). However, with technological advancements, many methodological improvements today can be considered direct improvements to the hardware circuit structure. Designers almost always obtain the corresponding hardware circuit structure by programming the improved methodology into the hardware circuit. Therefore, it cannot be said that a methodological improvement cannot be implemented using hardware physical modules. For example, a Programmable Logic Device (PLD) (such as a Field Programmable Gate Array (FPGA)) is such an integrated circuit whose logic function is determined by the user programming the device. Designers can program and "integrate" a digital system onto a PLD themselves, without needing chip manufacturers to design and manufacture dedicated integrated circuit chips. Furthermore, nowadays, instead of manually manufacturing integrated circuit chips, this programming is mostly implemented using "logic compiler" software. Similar to the software compiler used in program development, the original code before compilation must also be written in a specific programming language, called a Hardware Description Language (HDL). There are many HDLs, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, and RHDL (Ruby Hardware Description Language). Currently, the most commonly used are VHDL (Very-High-Speed ​​Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should also understand that by simply performing some logic programming on the method flow using one of these hardware description languages ​​and programming it into an integrated circuit, the hardware circuit implementing the logical method flow can be easily obtained.

[0044] The controller can be implemented in any suitable manner. For example, it can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicon Labs C8051F320. A memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also recognize that, in addition to implementing the controller in purely computer-readable program code form, the same functionality can be achieved by logically programming the method steps to make the controller take the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the means included therein for implementing various functions can also be considered as structures within the hardware component. Alternatively, the means for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0045] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0046] For ease of description, the above devices are described in terms of function, divided into various units. Of course, in implementing this specification, the functions of each unit can be implemented in one or more software and / or hardware.

[0047] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device and medium embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the description of the method embodiments.

[0048] The devices and media provided in this application are one-to-one with the methods. Therefore, the devices and media also have similar beneficial technical effects as their corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the devices and media will not be repeated here.

[0049] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0050] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0051] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0052] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0053] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0054] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0055] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0056] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0057] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A diagnostic method for a pre-charging circuit, characterized in that, include: An isolated power supply is output through a pre-set full-bridge resonant circuit to perform isolated charging based on the isolated power supply; By alternately turning on multiple full-bridge switches to complete the switching cycle and charging cycle, the voltage is increased in a stepwise manner to achieve constant current charging. The closed state of the main relay is determined by a pre-set detection circuit. If the main relay is closed, it is charged and outputs a high level; if the main relay is not closed, it cannot be charged and outputs a low level. The full-bridge resonant circuit includes a detection resistor R1; the detection resistor R1 is used to detect the primary current of the transformer in order to determine the status of the main relay. The closing state of the main relay is determined by a pre-set detection circuit, specifically including: The detection circuit includes operational amplifier U1 and operational amplifier U2; The operational amplifier U2 detects the current value flowing through the detection resistor R1 and converts the current value from a differential signal into a single-ended signal. The converted single-ended signal is transmitted to operational amplifier U1 for judgment to determine the closing state of the main relay. The closing state of the main relay is determined based on the preset threshold voltage and the current flowing through the detection resistor R1. If the current flowing through R1 does not exceed the current value corresponding to the threshold voltage, it indicates that the main relay KA is closed normally and U1 outputs a high level. If the current flowing through R1 exceeds the current value corresponding to the threshold voltage, it indicates that the main relay KA is not closed properly, and U1 outputs a low level.

2. The method according to claim 1, characterized in that, The method further includes: The full-bridge resonant circuit also includes an input capacitor C1, full-bridge switches Q1, Q2, Q3, and Q4, an inductor L1, and a resonant capacitor Cr. The input capacitor C1 is used to stabilize the input voltage. The full-bridge switches alternately conduct under the control signal to form a resonant current path. The resonant unit is composed of the inductor L1 and the resonant capacitor Cr, which generate resonance to achieve energy transfer.

3. The method according to claim 1, characterized in that, The step-up voltage increase for constant current charging specifically includes: A voltage step increase is achieved through a rectifier circuit for constant current charging; wherein the rectifier circuit includes rectifier diodes D1, D2, D3, and D4, a charging resistor R2, and a load capacitor C2; the rectifier diodes convert AC power into DC power; the charging resistor R2 and the load capacitor C2 form a charging circuit to achieve a voltage step increase according to the charging circuit.

4. The method according to claim 1, characterized in that, The method further includes: Determine the highest point current value of the primary current flowing through R1 during normal closure, and determine the corresponding threshold voltage based on the highest point current value. The expression for the threshold voltage is: Where Vref is the threshold voltage. This is the highest point current value of the primary current flowing through R1 when it is normally closed, and R1 is the sensing resistor.

5. The method according to claim 1, characterized in that, After the main relay is not closed, the method further includes: Trigger a pre-set fault warning mechanism to record the fault occurrence time, fault type, and current system status; The charging circuit is automatically cut off to prevent overcurrent or short circuit caused by relay sticking, and maintenance personnel are notified to perform maintenance tasks.

6. The method according to claim 1, characterized in that, The circuit is used in a pre-charging circuit, which includes an MCU, a detection circuit, a low-voltage power supply module, a full-bridge resonant circuit, a transformer T1, a rectifier circuit, and a main relay KA. The MCU is used to monitor and regulate the working status of each module, and to interact with each module and transmit commands through control signal lines; The low-voltage power supply module is used to provide a stable low-voltage power supply for the entire circuit; The primary side of transformer T1 is connected to the output terminal of the full-bridge resonant circuit, and the secondary side of transformer T1 is connected to the rectifier circuit to achieve electrical isolation between the input and output. The main relay KA is connected in series between the output of the rectifier circuit and the load capacitor C2, and is used as a switch for the charging path.

7. A diagnostic device for a pre-charge circuit, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor to enable the diagnostic device for a pre-charged circuit to perform the method as described in any one of claims 1-6.

8. A non-volatile computer storage medium storing computer-executable instructions, characterized in that, The computer-executable instructions are configured to be the method as described in any one of claims 1-6.

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