A fault detection circuit for a circuit protection element

Abstract

This invention provides a fault detection circuit for a circuit protection element, comprising a first circuit protection element, a second circuit protection element, a first optocoupler detection circuit, a second optocoupler detection circuit, and a fault feedback circuit. The first circuit protection element is connected in series in a first input line, and the second circuit protection element is connected in series in a second input line. The first optocoupler detection circuit is connected between the beginning and end of the first and second circuit protection elements, and the second optocoupler detection circuit is connected between the end of the first and second circuit protection elements. The outputs of the first and second optocoupler detection circuits are respectively connected to the fault feedback circuit. By utilizing the conduction and signal transmission characteristics of optocouplers, the circuit is simpler and less expensive.

Description

Technical Field

[0001] This invention relates to the field of circuit testing, and more specifically, to a fault detection circuit for a circuit protection element. Background Technology

[0002] Relays are widely used in energy storage and photovoltaic design. In battery high-voltage boxes, relays are used as active disconnection devices to cut off the connection between the battery and the main circuit of the PCS (Power Conversion System). They also serve as soft-start relays to meet the parallel connection requirements between battery clusters. In PCS design, relays are used as soft starters for DC buses and for inverter grid connection control of AC main power circuits. In testing equipment, multiple relays are designed to switch between them to achieve time-division multi-channel measurement. In these application scenarios, relays may stick, fail to close, or open abnormally. Therefore, effective fault detection of the relay's working status is particularly important.

[0003] As a key component for safety protection, fuses are mainly used in the main power connection of equipment to play the role of overcurrent protection. For example, small current fuses below the 100 ampere level basically do not have their own detection capability. When an overcurrent occurs and fuse testing is required, it can only be judged by voltage sampling. In many applications, due to cost considerations, voltage sampling is not added to all fuse branches.

[0004] Therefore, it is particularly important to effectively detect faults in the operating status of circuit protection components such as relays and fuses. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the working state of circuit protection elements cannot be effectively detected. In order to address the above problem, a fault detection circuit for circuit protection elements is provided.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is to provide a fault detection circuit for a circuit protection element, including a first circuit protection element, a second circuit protection element, a first optocoupler detection circuit, a second optocoupler detection circuit, and a fault feedback circuit. The first circuit protection element is connected in series in a first input line, and the second circuit protection element is connected in series in a second input line. The first input line and the second input line provide different voltages to the subsequent circuits. The first optocoupler detection circuit is connected between the first end of the first circuit protection element and the first end of the second circuit protection element, and the second optocoupler detection circuit is connected between the tail end of the first circuit protection element and the tail end of the second circuit protection element. The output terminals of the first optocoupler detection circuit and the second optocoupler detection circuit are respectively connected to the fault feedback circuit. The fault feedback circuit outputs a first signal when either the first optocoupler detection circuit or the second optocoupler detection circuit is cut off, and outputs a second signal when both the first optocoupler detection circuit and the second optocoupler detection circuit are turned on.

[0007] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the first optocoupler detection circuit includes a first optocoupler, the primary anode of the first optocoupler is connected to the first end of the first circuit protection element, the primary cathode of the first optocoupler is connected to the first end of the second circuit protection element, the secondary collector of the first optocoupler is connected to the fault feedback circuit, and the secondary emitter of the first optocoupler is grounded.

[0008] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the second optocoupler detection circuit includes a second optocoupler. The primary anode of the second optocoupler is connected to the tail end of the first circuit protection element, the primary cathode of the second optocoupler is connected to the tail end of the second circuit protection element, the secondary collector of the second optocoupler is connected to the fault feedback circuit, and the secondary emitter of the second optocoupler is grounded.

[0009] In the fault detection circuit of the circuit protection element described in this embodiment of the invention, the fault feedback circuit includes a driving source, a third resistor, a fourth resistor, a third diode, a fourth diode, a Zener diode, and a transistor; the third resistor is connected between the driving source and the output terminal of the first optocoupler detection circuit; the fourth resistor is connected between the driving source and the output terminal of the second optocoupler detection circuit; the anode of the third diode is connected to the output terminal of the first optocoupler detection circuit, the cathode of the third diode is connected to the cathode of the Zener diode, the anode of the fourth diode is connected to the output terminal of the second optocoupler detection circuit, the cathode of the fourth diode is connected to the cathode of the Zener diode, the anode of the Zener diode is connected to the base of the transistor, the collector of the transistor is connected to the driving source and the fault feedback port, and the emitter of the transistor is grounded.

[0010] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the first circuit protection element is a first relay, and the second circuit protection element is a second relay; the fault detection circuit of the circuit protection element further includes a control module, which is used to send drive signals to the first relay and the second relay, and to confirm whether the first relay and the second relay are normal according to the signal output by the fault feedback circuit.

[0011] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the first input line is connected to the positive power supply terminal of the DC power supply, and the second input line is connected to the negative power supply terminal of the DC power supply. The control module is used to send a closing signal to the first relay and the second relay, and to confirm that the first relay and the second relay are normal when the fault feedback circuit outputs a second signal; and to confirm that at least one of the first relay and the second relay is open-circuit fault when the fault feedback circuit outputs a first signal. The control module alternately sends closing signals to the first relay and the second relay. When the fault feedback circuit always outputs the second signal, it confirms that both the first relay and the second relay are stuck. It first outputs the first signal, and when the second signal is output after the first relay is closed, it confirms that the second relay is stuck. It first outputs the first signal, and when the second signal is output after the first relay is open and the second relay is closed, it confirms that the first relay is stuck.

[0012] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the first input line and the second input line are respectively connected to an AC power supply. The control module is used to send a closing signal to the first relay and the second relay, and when the fault feedback circuit periodically outputs the first signal and the second signal, it confirms that the first relay and the second relay are normal, and when the fault feedback always outputs the first signal, it confirms that at least one of the first relay and the second relay is open-circuit faulted.

[0013] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the first circuit protection element is a first fuse, the second circuit protection element is a second fuse, the first input line is connected to the positive power supply terminal of the DC power supply, and the second input line is connected to the negative power supply terminal of the DC power supply. The fault detection circuit of the circuit protection element further includes a control module, and the control module confirms that the first fuse and the second fuse are working normally when the fault feedback circuit outputs a second signal; and confirms that at least one of the first fuse and the second fuse has blown when the fault feedback circuit outputs a first signal.

[0014] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the first circuit protection element is a first fuse, the second circuit protection element is a second fuse, and the first input line and the second input line are respectively connected to an AC power supply. The fault detection circuit of the circuit protection element also includes a control module. When the fault feedback circuit periodically outputs a first signal and a second signal, the control module confirms that the first fuse and the second fuse are normal. When the fault feedback always outputs the first signal, it confirms that at least one of the first fuse and the second fuse has blown.

[0015] In the fault detection circuit of the circuit protection element described in the embodiment of the present invention, the fault feedback circuit further includes a fifth diode, which is connected between the driving source and the collector of the transistor.

[0016] The fault detection circuit for circuit protection elements provided in this embodiment of the invention has the following beneficial effects: by utilizing the conduction and signal transmission characteristics of optocouplers, it avoids designing sampling circuits to detect voltage and determine the status of circuit protection elements. The circuit is simpler and less expensive. At the same time, for high-voltage applications, the isolation function of optocouplers can meet the safety design requirements between strong and weak currents, and a wider voltage range detection can be designed. Attached Figure Description

[0017] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the first embodiment of the fault detection circuit of the circuit protection element provided by the present invention; Figure 2 This is a schematic diagram of a second embodiment of the fault detection circuit of the circuit protection element provided by the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] Hereinafter, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0021] Furthermore, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the components in the accompanying drawings.

[0022] In this application, unless otherwise expressly specified and limited, the term "connection" can refer to a manner of electrical connection for signal transmission, and "connection" can be a direct electrical connection or an indirect electrical connection through an intermediate medium.

[0023] like Figure 1The diagram shown is a schematic diagram of a first embodiment of a fault detection circuit for a circuit protection element provided by the present invention. The fault detection circuit includes a first circuit protection element 1, a second circuit protection element 2, a first optocoupler detection circuit 3, a second optocoupler detection circuit 4, and a fault feedback circuit 5. The first circuit protection element 1 is connected in series in the first input line L (live wire), and the second circuit protection element 2 is connected in series in the second input line N (neutral wire). The first input line L and the second input line N provide different voltages to the subsequent circuits. The first optocoupler detection circuit 3 is connected between the first end of the first circuit protection element 1 and the first end of the second circuit protection element 2. The second optocoupler detection circuit 4 is connected between the tail end of the first circuit protection element 1 and the tail end of the second circuit protection element 2. The output terminals of the first optocoupler detection circuit 3 and the second optocoupler detection circuit 4 are respectively connected to the fault feedback circuit 5. The fault feedback circuit 5 outputs a first signal when either the first optocoupler detection circuit 3 or the second optocoupler detection circuit 4 is turned off, and outputs a second signal when both the first optocoupler detection circuit 3 and the second optocoupler detection circuit 4 are turned on. In one embodiment, the first input line can be L (live wire) and the second input line can be N (neutral wire); or the first input line and the second input line can be connected to an AC power source respectively.

[0024] The fault detection circuit for circuit protection elements provided in this embodiment of the invention utilizes the conduction and signal transmission characteristics of optocouplers, avoiding the need to design sampling circuits to detect voltage and determine the status of circuit protection elements. The circuit is simpler and lower in cost. At the same time, for high-voltage applications, the isolation function of optocouplers can meet the safety design requirements between strong and weak currents, and a wider voltage range detection can be designed.

[0025] like Figure 2 The diagram shown is a schematic diagram of a second embodiment of the fault detection circuit of the circuit protection element provided in this invention. The first optocoupler detection circuit 3 includes a first optocoupler U1, which includes a primary side and a secondary side. The primary side includes a primary anode and a primary cathode, and the secondary side includes a secondary collector and a secondary emitter. The primary anode is connected to the first terminal Input+ / L of the first circuit protection element, the primary cathode is connected to the first terminal Input- / N of the second circuit protection element, the secondary collector is connected to the fault feedback circuit 5, and the secondary emitter is grounded Gnd.

[0026] In one embodiment, the first optocoupler detection circuit 3 further includes a first diode D1, the anode of the first diode D1 being connected to the primary cathode of the first optocoupler, and the cathode of the first diode being connected to the primary anode of the first optocoupler. The parallel diode D1 prevents reverse breakdown.

[0027] In one embodiment, the first optocoupler detection circuit further includes a first resistor R1, one end of which is connected to the primary cathode of the first optocoupler, and the other end of which is connected to the input- / N terminal of the second circuit protection element. By designing the first optocoupler U1 in series with the resistor R1, the conduction current of the first optocoupler U1 is limited.

[0028] In one embodiment, the second optocoupler detection circuit 4 includes a second optocoupler U2, which includes a primary side and a secondary side. The primary side includes a primary anode and a primary cathode, and the secondary side includes a secondary collector and a secondary emitter. The primary anode is connected to the output + / L terminal of the first circuit protection element, the primary cathode is connected to the output - / N terminal of the second circuit protection element, the secondary collector is connected to the fault feedback circuit 5, and the secondary emitter is grounded Gnd.

[0029] In one embodiment, the second optocoupler detection circuit 4 further includes a second diode D2, the anode of which is connected to the primary cathode of the second optocoupler U2, and the cathode of which is connected to the primary anode of the second optocoupler U2. The parallel diode D2 prevents reverse breakdown.

[0030] In one embodiment, the second optocoupler detection circuit 4 further includes a second resistor R2. One end of the second resistor R2 is connected to the primary cathode of the second optocoupler U2, and the other end of the second resistor R2 is connected to the output- / N terminal of the second circuit protection element. By designing the second optocoupler U2 in series with the resistor R2, the conduction current of the second optocoupler U2 is limited.

[0031] This invention utilizes a dual optocoupler detection circuit, consisting of a first optocoupler detection circuit 3 and a second optocoupler detection circuit 4. The operation is briefly described as follows: When an input voltage is applied to the input terminals of the first and second circuit protection elements, the first optocoupler U1 conducts, transmitting the input voltage signal to the fault feedback circuit 5. When both the first and second circuit protection elements 1 and 2 are closed, the second optocoupler U2 conducts, transmitting the input voltage signal to the fault feedback circuit 5. This design eliminates the need for voltage sampling, achieving signal transmission through the first and second optocouplers U1 and U2. It also provides isolation capabilities, preventing direct connection of the circuits of the first and second circuit protection elements 1 and 2 in high-voltage applications to low-voltage control circuits, thus avoiding safety design issues.

[0032] In one embodiment, the fault feedback circuit 5 includes a drive source V. CC The circuit consists of a third resistor R3, a fourth resistor R4, a third diode D3, a fourth diode D4, a Zener diode Z1, and a transistor Q1; the third resistor R3 is connected between the driving source VCC and the output terminal of the first optocoupler detection circuit 3; the fourth resistor R4 is connected to the driving source VCC. CC The first optocoupler detection circuit 3 is connected to the output terminal of the second optocoupler detection circuit 4; the anode of the third diode D3 is connected to the output terminal of the first optocoupler detection circuit 3, and the cathode of the third diode D3 is connected to the cathode of the Zener diode Z1; the anode of the fourth diode D4 is connected to the output terminal of the second optocoupler detection circuit 4, and the cathode of the fourth diode D4 is connected to the cathode of the Zener diode; the anode of the Zener diode Z1 is connected to the base of the transistor Q1; and the collector of the transistor Q1 is connected to the driving source V. CC The transistor Q1 is connected to the fault feedback port MCU IO, and its emitter is grounded to Gnd.

[0033] The working process of the fault feedback circuit 5 of this invention is briefly described as follows: The Vcc power supply is designed as the driving source, and in the system, it is generally powered by an auxiliary power supply. It is connected to the secondary side of the first optocoupler U1 and the second optocoupler U2 via the third resistor R3 and the fourth resistor R4, respectively. When the first optocoupler U1 is not working, the two ends of the transistor on the secondary side of the first optocoupler U1 are at a high level. The driving source Vcc, after passing through the third resistor R3 and the third diode D3, breaks down the Zener diode Z1, and current enters the base of transistor Q1. Transistor Q1 conducts, sending a low-level signal to the fault feedback port MCU. IO; When the first optocoupler U1 starts working, the driving source Vcc is pulled low by the secondary transistor of the first optocoupler U1 after passing through the third resistor R3, and there is no effective voltage to break down the Zener diode Z1; When the first circuit protection element 1 or the second circuit protection element 2 is open, the driving source Vcc breaks down the Zener diode Z1 after passing through the fourth resistor R4 and the fourth diode D4, and the current enters the base of the transistor Q1. The transistor Q1 conducts and sends a low-level signal to the fault feedback port MCU IO. If the tested component is a fuse, it can be determined that the fuse is faulty and open-circuited. If it is a relay, it can be determined whether the relay is faulty based on whether a relay drive is provided and the low-level signal of the fault feedback port MCU IO. When the first circuit protection element 1 and the second circuit protection element 2 are turned on, the driving source Vcc is pulled low by the secondary transistor of the second optocoupler U2 after passing through the fourth resistor R4. There is no effective voltage to break down the fourth diode D4 and the Zener diode Z1, causing the transistor Q1 to not work. A high-level signal is sent to the fault feedback port MCU IO. At this time, if the controller provides a relay drive, it is in normal working condition. If no relay drive is provided, it indicates that the relay has a sticking fault.

[0034] In one embodiment, the first circuit protection element 1 is a first relay, and the second circuit protection element 2 is a second relay; the fault detection circuit of the circuit protection element further includes a control module, which is used to send drive signals to the first relay and the second relay, and to confirm whether the first relay and the second relay are normal according to the signal output by the fault feedback circuit.

[0035] In one embodiment, the first input line is connected to the positive power supply terminal of the DC power supply, and the second input line is connected to the negative power supply terminal of the DC power supply. The control module is used to send a closing signal to the first relay and the second relay, and to confirm that the first relay and the second relay are normal when the fault feedback circuit outputs a second signal; and to confirm that at least one of the first relay and the second relay is open-circuit fault when the fault feedback circuit outputs a first signal. The control module alternately sends closing signals to the first relay and the second relay. When the fault feedback circuit always outputs the second signal, it confirms that both the first relay and the second relay are stuck. It first outputs the first signal, and when the second signal is output after the first relay is closed, it confirms that the second relay is stuck. It first outputs the first signal, and when the second signal is output after the first relay is open and the second relay is closed, it confirms that the first relay is stuck.

[0036] In one embodiment, the first input line and the second input line are respectively connected to an AC power source; The control module is used to send a closing signal to the first relay and the second relay, and when the fault feedback circuit periodically outputs the first signal and the second signal, it confirms that the first relay and the second relay are normal, and when the fault feedback always outputs the first signal, it confirms that at least one of the first relay and the second relay is open-circuit faulted.

[0037] In one embodiment, the first circuit protection element is a first fuse, the second circuit protection element is a second fuse, the first input line is connected to the positive power supply terminal of the DC power supply, and the second input line is connected to the negative power supply terminal of the DC power supply. The fault detection circuit of the circuit protection element further includes a control module, and the control module confirms that the first fuse and the second fuse are working normally when the fault feedback circuit outputs a second signal; and confirms that at least one of the first fuse and the second fuse has blown when the fault feedback circuit outputs a first signal.

[0038] In one embodiment, the first circuit protection element is a first fuse, the second circuit protection element is a second fuse, and the first input line and the second input line are respectively connected to an AC power supply. The fault detection circuit of the circuit protection element also includes a control module. When the fault feedback circuit periodically outputs a first signal and a second signal, the control module confirms that the first fuse and the second fuse are normal. When the fault feedback circuit always outputs the first signal, it confirms that at least one of the first fuse and the second fuse has blown.

[0039] The circuit designed in this invention can be used for fault detection in both AC and DC voltage applications. When used for DC voltage detection, the input terminals of the first circuit protection element 1 and the second circuit protection element 2 are normally powered by DC. If the fault feedback port MCU IO is high, the circuit is operating normally. If a low level is detected, and the relay has been driven by the controller, the detected element is faulty. When used for AC voltage detection, the input terminals of the first circuit protection element 1 and the second circuit protection element 2 are normally powered by AC. If the fault feedback port MCU IO detects periodic high and low level changes, the circuit is operating normally. If the level remains low, and the relay has been driven by the controller, the detected element is faulty.

[0040] The circuit designed in this invention only needs to detect the signal of a fault feedback port MCU IO to determine whether there is a relay failure in the circuit. It has low implementation cost, high reliability, and low controller resource consumption.

[0041] This invention designs a circuit that supports dual-end detection, meaning it can simultaneously detect two components in both the positive and negative circuits: the first circuit protection element 1 and the second circuit protection element 2. Alternatively, it can detect two components in both the AC phase and neutral circuits: the first circuit protection element 1 and the second circuit protection element 2. When the first circuit protection element 1 alone fails with an open circuit or a short circuit, the fault feedback port MCU IO goes low, indicating a fault. Similarly, when the second circuit protection element 2 alone fails with an open circuit or a short circuit, the fault feedback port MCU IO goes low, indicating a fault. When either the first circuit protection element 1 or the second circuit protection element 2 fails with an open circuit, the fault feedback port MCU IO goes low, indicating a fault.

[0042] The circuit designed in this invention can detect fault feedback signals in real time without needing to sample and calculate effective values ​​or other data for judgment. It can identify faults with only simple judgment logic, resulting in a faster response.

[0043] This invention designs a circuit that, combined with control logic, can accurately determine if either the first circuit protection element 1 or the second circuit protection element 2 of the relay being tested in the circuit is stuck together, thus preventing the fault from escalating. The working process is briefly described as follows: When voltage is applied to the input terminal of the tested element, the first circuit protection element 1 is first closed. The controller checks if the fault feedback port MCU IO goes high. If it does, it indicates that the second circuit protection element 2 is stuck; otherwise, it is normal. Subsequently, the first circuit protection element 1 is opened, and then the second circuit protection element 2 is closed. The controller checks if the fault feedback port MCU IO goes high. If it does, it indicates that the second circuit protection element 2 is stuck; otherwise, it is normal.

[0044] The circuit design and operation of this invention are briefly described below: first step: The input terminals of the first circuit protection element 1 and the second circuit protection element 2 of the tested component are connected to a voltage. This voltage is required by the circuit design to be sufficient to turn on the first optocoupler U1. By designing the value of the first resistor R1, the first optocoupler U1 is guaranteed to conduct normally under different applications, and the current is limited within a certain range. After the first optocoupler U1 is turned on by this voltage, the level of the original driving source Vcc after passing through the third resistor R3 is pulled low to ground Gnd by the first optocoupler U1. At this time, since the first circuit protection element 1 and the second circuit protection element 2 of the tested component are in the off state, the fourth diode D4 and the Zener diode Z1 are at a relatively high potential, the third diode D3 is in the off state, and the driving source Vcc, the fourth resistor R4, the fourth diode D4, the Zener diode Z1, and the transistor Q1 form a current loop. Q1 is turned on, and the fault feedback port MCU IO detects a low level.

[0045] In this state, the following judgment logic is made: If it is a fuse application: determine that the fuse is open.

[0046] If it is a relay application: If a relay driver is added to the system, and the controller provides a relay driver, but the fault feedback port MCU IO detects a low level, it can be determined that the relay is open-circuited and cannot respond to the driver normally.

[0047] If no relay is driven, it is considered normal.

[0048] Step Two: When the detected component is closed, the value of the second resistor R2 is designed to be the same as that of the first resistor R1, ensuring that the second optocoupler U2 conducts normally under different applications and the current is limited within a certain range. After the voltage turns on the second optocoupler U2, the level of the original driving source Vcc after passing through the fourth resistor R4 is pulled down to Gnd by the second optocoupler U2. The Zener diode Z1 cannot be broken down by the effective level, the transistor Q1 is in a non-conducting state, and the fault feedback port MCU IO detects a high level. In this state, the following judgment logic is made: If it is a fuse application: it is determined that the fuse is working normally.

[0049] If it is a relay application: If a relay driver is added to the system, and the controller provides a relay driver, and the fault feedback port MCU IO detects a high level, then it can be determined that the relay is responding normally.

[0050] If the relay is not driven, it is considered that the relay is short-circuited and stuck.

[0051] Design a method for detecting relay short circuit adhesion: First, close the first circuit protection element 1 of the tested element. The controller judges whether the fault feedback port MCU IO becomes high. If it does, it means that the second circuit protection element 2 of the tested element is stuck. Otherwise, it is normal. Then, disconnect the first circuit protection element 1 of the tested element and close the second circuit protection element 2 of the tested element. The controller judges whether the fault feedback port MCU IO becomes high. If it does, it means that the tested element (3) is stuck. Otherwise, it is normal.

[0052] This invention fully utilizes the characteristics of electronic components, such as the isolated signal transmission characteristics of the optocoupler and the reverse blocking characteristics of the Zener diode Z1. By combining the pain points of the tested component in engineering applications and the damage characteristics of components such as relays and fuses that have no feedback contacts but are easily damaged, this active fault detection circuit is designed.

[0053] By utilizing the conduction and signal transmission characteristics of optocouplers, the need to design sampling circuits to detect voltage and determine relay status is avoided. The circuit is simpler and the cost is lower. At the same time, for high-voltage applications, the isolation function of optocouplers can meet the safety design requirements between strong and weak currents, and a wider voltage range detection can be designed. It has both DC detection and AC application detection capabilities, which broadens the application scenarios of the circuit; It has a dual-end detection function and can simultaneously detect two relays or fuses in the circuit; In one embodiment, the fault feedback circuit 5 further includes a fifth diode D5, which is connected between the driving source Vcc and the collector of the transistor Q1. This invention designs a fault feedback circuit 5 that visualizes the relay's operating status. The illuminated fifth diode D5 indicator directly reflects the operating status of the detected component. The working process is briefly described as follows: if the fifth diode D5 is lit, it indicates that the first circuit protection element 1 and the second circuit protection element 2 are not working, or that there is no voltage input within the design range at the input terminals of the first circuit protection element 1 and the second circuit protection element 2; if the fifth diode D5 is not lit, for applications where the first circuit protection element 1 and the second circuit protection element 2 are fuses, it is considered that the fuses are working normally; for applications where the first circuit protection element 1 and the second circuit protection element 2 are relays, the fault status is determined by whether the relay is driven by the controller (if the controller drives it, it is considered normal; if the controller does not drive it, it is considered that the relay is stuck). This application designs an indicator circuit to visualize the relay's operating status, facilitating on-site maintenance.

[0054] This invention provides real-time detection and feedback with a rapid response, eliminating the need for complex voltage detection logic. In response to the pain point of easy adhesion in the application of the relay components being tested, an adhesion detection logic was designed. Any abnormal adhesion can be accurately detected by the detection logic.

[0055] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software programs, it can be implemented entirely or partially in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device including one or more servers, data centers, etc., that can be integrated with the medium. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)). In the embodiments of this application, the computer may include the aforementioned devices.

[0056] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0057] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

[0058] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A fault detection circuit for a circuit protection element, characterized in that, The system includes a first circuit protection element, a second circuit protection element, a first optocoupler detection circuit, a second optocoupler detection circuit, and a fault feedback circuit. The first circuit protection element is connected in series in a first input line, and the second circuit protection element is connected in series in a second input line. The first and second input lines provide different voltages to the subsequent circuits. The first optocoupler detection circuit is connected between the first and second ends of the first and second circuit protection elements, and the second optocoupler detection circuit is connected between the second and third ends of the first and second circuit protection elements. The outputs of the first and second optocoupler detection circuits are respectively connected to the fault feedback circuit. The fault feedback circuit outputs a first signal when either the first or second optocoupler detection circuit is turned off, and outputs a second signal when both the first and second optocoupler detection circuits are turned on.

2. The fault detection circuit of the circuit protection element according to claim 1, characterized in that, The first optocoupler detection circuit includes a first optocoupler, the primary anode of the first optocoupler is connected to the first end of the first circuit protection element, the primary cathode of the first optocoupler is connected to the first end of the second circuit protection element, the secondary collector of the first optocoupler is connected to the fault feedback circuit, and the secondary emitter of the first optocoupler is grounded.

3. The fault detection circuit of the circuit protection element according to claim 1, characterized in that, The second optocoupler detection circuit includes a second optocoupler. The primary anode of the second optocoupler is connected to the tail end of the first circuit protection element, the primary cathode of the second optocoupler is connected to the tail end of the second circuit protection element, the secondary collector of the second optocoupler is connected to the fault feedback circuit, and the secondary emitter of the second optocoupler is grounded.

4. The fault detection circuit of the circuit protection element according to claim 1, characterized in that, The fault feedback circuit includes a driver, a third resistor, a fourth resistor, a third diode, a fourth diode, a Zener diode, and a transistor. The third resistor is connected between the driver and the output of the first optocoupler detection circuit. The fourth resistor is connected between the driver and the output of the second optocoupler detection circuit. The anode of the third diode is connected to the output of the first optocoupler detection circuit, and the cathode of the third diode is connected to the cathode of the Zener diode. The anode of the fourth diode is connected to the output of the second optocoupler detection circuit, and the cathode of the fourth diode is connected to the cathode of the Zener diode. The anode of the Zener diode is connected to the base of the transistor. The collector of the transistor is connected to the driver and the fault feedback port, and the emitter of the transistor is grounded.

5. The fault detection circuit of the circuit protection element according to claim 4, characterized in that, The first circuit protection element is a first relay, and the second circuit protection element is a second relay; the fault detection circuit of the circuit protection element further includes a control module, which is used to send drive signals to the first relay and the second relay, and to confirm whether the first relay and the second relay are normal according to the signal output by the fault feedback circuit.

6. The fault detection circuit of the circuit protection element according to claim 5, characterized in that, The first input line is connected to the positive power supply terminal of the DC power supply, and the second input line is connected to the negative power supply terminal of the DC power supply. The control module is used to send a closing signal to the first relay and the second relay, and to confirm that the first relay and the second relay are normal when the fault feedback circuit outputs a second signal; and to confirm that at least one of the first relay and the second relay is open-circuit fault when the fault feedback circuit outputs a first signal. The control module alternately sends closing signals to the first relay and the second relay. When the fault feedback circuit always outputs the second signal, it confirms that both the first relay and the second relay are stuck. It first outputs the first signal, and when the second signal is output after the first relay is closed, it confirms that the second relay is stuck. It first outputs the first signal, and when the second signal is output after the first relay is open and the second relay is closed, it confirms that the first relay is stuck.

7. The fault detection circuit of the circuit protection element according to claim 5, characterized in that, The first input line and the second input line are respectively connected to an AC power source; The control module is used to send closed signals to the first relay and the second relay, and when the fault feedback circuit periodically outputs the first signal and the second signal, it confirms that the first relay and the second relay are normal, and when the fault feedback circuit always outputs the first signal, it confirms that at least one of the first relay and the second relay is open-circuit faulted.

8. The fault detection circuit of the circuit protection element according to claim 4, characterized in that, The first circuit protection element is a first fuse, the second circuit protection element is a second fuse, the first input line is connected to the positive power supply terminal of the DC power supply, and the second input line is connected to the negative power supply terminal of the DC power supply. The fault detection circuit of the circuit protection element further includes a control module, and the control module confirms that the first fuse and the second fuse are working normally when the fault feedback circuit outputs a second signal; and confirms that at least one of the first fuse and the second fuse has blown when the fault feedback circuit outputs a first signal.

9. The fault detection circuit of the circuit protection element according to claim 4, characterized in that, The first circuit protection element is a first fuse, the second circuit protection element is a second fuse, and the first input line and the second input line are respectively connected to an AC power supply; The fault detection circuit of the circuit protection element also includes a control module. When the fault feedback circuit periodically outputs a first signal and a second signal, the control module confirms that the first fuse and the second fuse are normal. When the fault feedback circuit always outputs the first signal, it confirms that at least one of the first fuse and the second fuse has blown.

10. The fault detection circuit of the circuit protection element according to claim 4, characterized in that, The fault feedback circuit also includes a fifth diode, which is connected between the drive source and the collector of the transistor.

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