Electric leakage detection system, electric leakage sensor and control panel

Abstract

The utility model discloses an electric leakage detection system, an electric leakage sensor and a control panel, and belongs to the technical field of electric leakage detection. The system comprises a detection device, an electric leakage filter circuit and a signal processing circuit, the detection device is connected with a power line, and the detection device is configured to detect and output a power signal of the power line; the electric leakage filter circuit is provided with a first input end and a first output end, and the first input end is connected with the detection device; the signal processing circuit is provided with a second input end and a second output end, the second input end is connected with the first output end, the second output end is configured to output a state signal, and the state signal is used for representing an electric leakage detection result. According to the application, the influence of surge signals caused by lightning stroke on power supply signals can be improved through filtering of the electric leakage filter circuit, so that subsequent circuits can be protected from being impacted by the surge signals caused by the lightning stroke, the safety of electric leakage detection is ensured, and reliable state signals representing electric leakage detection results are obtained through the signal processing circuit.

Description

Technical Field

[0001] This application belongs to the field of leakage current detection technology, specifically relating to a leakage current detection system, a leakage current sensor, and a control board. Background Technology

[0002] With the widespread use of electrical equipment and systems, leakage current can lead to equipment failure, fires, or personal injury. Therefore, detecting leakage current by detecting power signals is crucial for ensuring electrical safety. However, in the event of a lightning strike, a surge signal is generated, causing a momentary increase in the power signal and thus affecting leakage current detection. Utility Model Content

[0003] Purpose of the utility model: This application provides a leakage current detection system, sensor and control board, which aims to improve the impact of surge signals caused by lightning strikes on power signals.

[0004] Technical solution: This application provides a leakage current detection system, which includes:

[0005] A detection device is configured to detect and output a power signal from the power line.

[0006] A leakage current filtering circuit has a first input terminal and a first output terminal, with the first input terminal connected to a detection device;

[0007] The signal processing circuit has a second input terminal and a second output terminal. The second input terminal is connected to the first output terminal, and the second output terminal is configured to output a status signal, which is used to characterize the leakage current detection result.

[0008] This application also provides a control board, including the above-described leakage current detection system.

[0009] This application also provides an electrical device, including the control board described above.

[0010] The beneficial effects of this application are as follows: This application provides a leakage current detection system, which includes a detection device, a leakage current filtering circuit, and a signal processing circuit. The detection device is connected to a power line and is configured to detect and output a power signal from the power line. The leakage current filtering circuit has a first input terminal and a first output terminal, with the first input terminal connected to the detection device. The signal processing circuit has a second input terminal and a second output terminal, with the second input terminal connected to the first output terminal. The second output terminal is configured to output a status signal, which characterizes the leakage current detection result. This application places the leakage current filtering circuit between the detection device and the signal processing circuit. By filtering through the leakage current filtering circuit, the influence of surge signals caused by lightning strikes on the power signal can be reduced, thereby protecting subsequent circuits from the impact of lightning surge signals and ensuring the safety of leakage current detection. Furthermore, the signal processing circuit can obtain a reliable status signal characterizing the leakage current detection result.

[0011] The leakage current sensor in this application embodiment includes all the technical features and effects of the leakage current detection system described above, and will not be repeated here.

[0012] The control board of this application embodiment includes all the technical features and effects of the above-described leakage current detection system, and will not be repeated here. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic block diagram of a leakage current detection system proposed in this application;

[0015] Figure 2 This is a schematic block diagram of another leakage current detection system proposed in this application;

[0016] Figure 3 This is a schematic block diagram of another leakage current detection system proposed in this application;

[0017] Figure 4 This is a schematic block diagram of another leakage current detection system proposed in this application;

[0018] Figure 5 This is a circuit diagram of a leakage current detection system proposed in this application;

[0019] Figure 6 This is a circuit block diagram of the leakage current sensor proposed in this application;

[0020] Figure 7 This is a circuit diagram of the relay proposed in this application.

[0021] Explanation of reference numerals in the attached figures: 10, Detection device; 11, First detection terminal; 12, Second detection terminal; 14, Detection output terminal; 20, Leakage current filtering circuit; 21, First input terminal; 22, First output terminal; 30, Signal processing circuit; 31, Second input terminal; 32, Second output terminal; 33, Digital output unit; 331, First comparator; 3311, First terminal; 3312, Second terminal; 3313, Third terminal; 34, Noise filtering unit; 341. 342. Third input terminal; 35. Amplification unit; 351. Fourth input terminal; 352. Fourth output terminal; 36. Low-frequency filter unit; 361. Fifth input terminal; 362. Fifth output terminal; 37. Sixth output terminal; 38. Analog output unit; 40. Self-test circuit; 41. AC self-test unit; 411. First self-test input terminal; 412. Second self-test input terminal; 413. First self-test output terminal; 414. Second self-test output terminal. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In the description of this application, it should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the application. Terms such as "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0024] This application provides a leakage current detection system, a leakage current sensor, and a control board, which are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, in the following embodiments, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.

[0025] The applicant noted that with the widespread use of electrical equipment and systems, leakage current can lead to equipment malfunctions, fires, or personal injury. Therefore, detecting leakage current by detecting power signals is crucial for ensuring electrical safety. However, in the event of a lightning strike, a surge signal is generated, causing a momentary increase in the power signal and thus affecting leakage current detection.

[0026] In view of the above, embodiments of this application provide a leakage current detection system, which aims to overcome at least one of the above-mentioned technical problems.

[0027] Please see Figures 1 to 5 As shown, this application provides a leakage current detection system, including: a detection device 10 configured to detect and output a power signal from a power line; a leakage current filtering circuit 20 having a first input terminal 21 and a first output terminal 22, the first input terminal 21 being connected to the detection device 10; and a signal processing circuit 30 having a second input terminal 31 and a second output terminal 32, the second input terminal 31 being connected to the first output terminal 22, the second output terminal 32 being configured to output a status signal, the status signal being used to characterize the leakage current detection result.

[0028] It's important to understand that the detection device 10 can be a detection coil, primarily used to detect leakage current in the circuit. The detection coil utilizes the principle of electromagnetic induction to monitor changes in current. When current flows through a conductor, it generates a magnetic field around it. Typically, the phase wire and neutral wire pass through the detection coil together. Under normal circumstances, the currents in these two wires are equal in magnitude and opposite in direction, causing the magnetic fields generated in the coil to cancel each other out. If leakage occurs in the circuit, the inflow and outflow currents are no longer balanced, resulting in an unbalanced magnetic field in the coil. This unbalanced magnetic field induces a voltage signal in the detection coil. Therefore, under normal circumstances, the currents in the live wire and neutral wire are equal in magnitude and opposite in direction, thus canceling out the magnetic fields generated in the detection coil. If there is leakage in the live wire, the current flows from the live wire to ground, and the live wire current is greater than the neutral wire current. If the neutral wire leaks current, the current flows from the neutral wire to ground. The neutral wire current is greater than the live wire current, causing an imbalance in the current. This will generate an additional magnetic field change in the coil of the detection device 10, resulting in an induced electromotive force. This causes the detection device 10 to detect and output a corresponding signal. In this application, the power signal of the output power line of the detection device 10 is the signal corresponding to the induced electromotive force generated in the coil of the detection device 10.

[0029] It should be noted that in the event of a lightning strike, a surge signal will be generated, which will cause a momentary increase in the power supply signal, thereby impacting the subsequent circuits of the detection device 10. The leakage current filter circuit 20 is mainly used to absorb or transfer the surge energy, thereby protecting the subsequent circuits from damage, and protecting the subsequent circuits output by the lightning surge pulse signal from the impact of the lightning surge pulse signal on the subsequent circuits of the detection device 10.

[0030] Furthermore, the signal processing circuit 30 further processes the power signal after it has been processed by the leakage current filtering circuit 20, such as amplifying and removing noise. The signal processing circuit 30 outputs a status signal characterizing the leakage current detection result. It should be noted that the status signal characterizing the leakage current detection result can be a high or low level to directly indicate whether there is a leakage current in the circuit, or it can be more complex analog signal data to provide more detailed information for subsequent analysis and processing. This diverse signal output method allows the system to flexibly adapt to different application scenarios and provide accurate leakage current detection results.

[0031] Through the above technical solution, this application places the leakage current filtering circuit 20 between the detection device 10 and the signal processing circuit 30, that is, it has made a specific hardware protection circuit for leakage current characteristics, which can protect the leakage current circuit from the impact of lightning surge pulse signal, and does not affect the identification output of normal power signal leakage current; this application uses the leakage current filtering circuit 20 to filter, which can improve the impact of lightning surge signal on power signal, thereby protecting the subsequent circuit from the impact of lightning surge signal, ensuring the safety of leakage current detection, and the signal processing circuit 30 can obtain a reliable status signal characterizing the leakage current detection result.

[0032] In some embodiments, the leakage current filtering circuit 20 includes a first capacitor and a first TVS diode, which are connected in parallel between the first input terminal 21 and the first output terminal 22.

[0033] Please see Figure 5As shown, exemplarily, the leakage current filtering circuit 20 includes a capacitor C1 and a TVS diode D1. Capacitor C1 is the first capacitor, and TVS diode D1 is the first TVS diode. Capacitor C1 and TVS diode D1 are connected in parallel between the first input terminal 21 and the first output terminal 22, meaning one end of capacitor C1 is connected to one end of TVS diode D1, and both ends are connected to the first input terminal 21 and the first output terminal 22, respectively. The other ends of capacitor C1 and TVS diode D1 are grounded. TVS diode D1 can be a bidirectional TVS diode. It should be noted that to protect subsequent circuits from damage, TVS diode D1 can be a high-power TVS diode, and the capacitance value of capacitor C1 is limited to below 1nF to prevent signal distortion. The function of TVS diode D1 ensures that if the energy coupled from the power signal output by the detection device 10 is too large, it will not damage subsequent devices.

[0034] In the leakage current filtering circuit 20, the first capacitor smooths high-frequency noise and voltage spikes in the power supply signal. Connected in parallel, the capacitor absorbs and stores instantaneous voltage changes, reducing their impact on subsequent circuits. The TVS diode is used to protect the circuit from transient voltage surges. When an overvoltage occurs in the circuit (such as a lightning surge signal), the TVS diode quickly conducts, bypassing the excessive current to ground, thus protecting other components in the circuit. Furthermore, by connecting the first capacitor and the first TVS diode in parallel, high-frequency noise and transient voltage spikes can be effectively filtered out, protecting the stability and safety of the circuit. This, in turn, protects subsequent circuits from lightning surge signals, ensuring the safety of leakage current detection.

[0035] Please see Figure 2 As shown, in some embodiments, the status signal output by the second output terminal 32 is a digital signal; the signal processing circuit 30 includes: a digital output unit 33, the digital output unit 33 includes a first comparator 331, the first comparator 331 has a first terminal 3311, a second terminal 3312 and a third terminal 3313, the first terminal 3311 is connected to the second input terminal 31, the second terminal 3312 is configured to input a preset leakage current threshold value, and the third terminal 3313 is connected to the second output terminal 32.

[0036] It should be understood that the first terminal 3311 is the inverting input terminal of the first comparator 331, the second terminal 3312 is the non-inverting input terminal of the first comparator 331, and the third terminal 3313 is the output terminal of the first comparator 331. The second terminal 3312 is configured to input a preset leakage threshold value. The first terminal 3311 is connected to the second input terminal 31 to receive the power signal processed by the leakage filter circuit 20. The first comparator 331 compares the signal input to the first terminal 3311 with the signal input to the second terminal 3312 and outputs the corresponding level signal from the third terminal 3313 to directly indicate whether there is leakage in the power line through high and low levels. It should be noted that the preset leakage threshold value can be set according to the actual scheme requirements. When the signal input to the first terminal 3311 reaches the preset leakage threshold value, the level output of the third terminal 3313 flips to indicate that leakage is detected.

[0037] Please see Figure 2 As shown, in some embodiments, the signal processing circuit 30 further includes a noise filtering unit 34, having a third input terminal 341 and a third output terminal 342. The third input terminal 341 is connected to the first output terminal 22, and the third output terminal 342 is connected to the first terminal 3311. The noise filtering unit 34 is configured to filter out preset noise signals in the power supply signal. In this application, the noise filtering unit can be designed to retain signals below 10kHz. However, it should be noted that this description is merely illustrative and does not constitute a limitation on this solution. The specific design of the filtering unit can be adjusted according to actual needs.

[0038] It is important to understand that noise may interfere with the accuracy of leakage current detection, leading to false alarms or missed alarms. By further filtering out noise, it can be ensured that the detection equipment accurately identifies real leakage current events. Furthermore, the power signal processed by the leakage current filtering circuit 20 is filtered out by the noise filtering unit 34 to ensure the reliability and accuracy of leakage current detection.

[0039] Please see Figure 2 As shown, in some embodiments, the signal processing circuit 30 further includes an amplification unit 35, having a fourth input terminal 351 and a fourth output terminal 352. The fourth input terminal 351 is connected to the first output terminal 22, and the fourth output terminal 352 is connected to the first terminal 3311. The amplification unit 35 is configured to amplify the power signal to a preset factor. In this application, the amplification unit 35 can amplify the power signal to a factor of up to 200. It should be noted that this description is merely illustrative and does not constitute a limitation on this solution. The specific design of the amplification unit can be adjusted according to actual needs.

[0040] In some embodiments, the fourth input terminal 351 is connected to the third output terminal 342, the fourth output terminal 352 is connected to the first terminal 3311, and the amplification unit 35 is used to amplify the power signal processed by the noise filtering unit 34.

[0041] It's important to understand that leakage current signals are typically very small, especially in the early detection stages. Amplifying the signal makes these weak leakage current signals easier to detect and analyze, thus allowing for more sensitive identification of the leakage current's presence. Furthermore, amplification improves the signal-to-noise ratio, making the useful leakage current signal more prominent in the background noise, which helps reduce false alarms and missed alarms.

[0042] Please see Figure 2 As shown, in some embodiments, the signal processing circuit 30 further includes a low-frequency filtering unit 36, having a fifth input terminal 361 and a fifth output terminal 362. The fifth input terminal 361 is connected to the first output terminal 22, and the fifth output terminal 362 is connected to the first terminal 3311. The low-frequency filtering unit 36 ​​is configured to filter out preset high-frequency signals from the power supply signal. In this application, the low-frequency filtering unit 36 ​​can filter out noise above 300Hz in the power supply signal. It should be noted that this description is merely illustrative and does not constitute a limitation on this solution. The specific design of the low-frequency filtering unit can be adjusted according to actual needs.

[0043] In some embodiments, the fifth input terminal 361 is connected to the fourth output terminal 352, the fifth output terminal 362 is connected to the first terminal 3311, and the low-frequency filtering unit 36 ​​is used to filter out the power signal processed by the amplification unit 35.

[0044] It is important to understand that the amplification unit 35 not only amplifies useful signals, but also amplifies noise, especially high-frequency noise. The low-frequency filtering unit 36 ​​can effectively filter out this high-frequency noise. Filtering out high-frequency noise interference can improve the stability of the entire system and reduce malfunctions and unnecessary oscillations.

[0045] For example, such as Figure 2 and Figure 5 As shown, the noise filtering unit 34 includes an inductor L1, a capacitor C2, a capacitor C3, a capacitor C4, and a capacitor C5. One end of the inductor L1 is connected to the third input terminal 341, and the other end of the inductor L1 is connected to one end of the capacitors C2, C3, C4, and C5. One end of each of the capacitors C2, C3, C4, and C5 is connected to the third output terminal 342. The other ends of the capacitors C2, C3, C4, and C5 are grounded. That is, capacitors C2, C3, C4, and C5 are connected in parallel between the other end of the inductor L1 and the third output terminal 342.

[0046] It should be noted that a resistor R1 is connected between the third input terminal 341 and the first output terminal 22. The resistor R1 adjusts the level of the input signal to match the amplification of the leakage signal by the subsequent amplification unit 35.

[0047] In the noise filtering unit 34, the power signal processed by the leakage current filtering circuit 20 passes sequentially through resistor R1 and inductor L1, with multiple capacitors connected in parallel after inductor L1. This achieves a filter that selectively allows signal frequencies to pass through, effectively filtering out preset noise signals while allowing low-frequency signals to pass smoothly, providing a stable signal environment for the circuit. Additionally, the input signal level is adjusted via resistor R1 to match the amplification of the leakage current signal by the subsequent operational amplifier.

[0048] The amplification unit 35 includes resistors R2, R3, R4, R5, R6, R7, and R8, capacitors C6 and C7, operational amplifier U1, and operational amplifier U2. The fourth input terminal 351 is connected to one end of resistor R2, one end of resistor R3, the inverting input terminal of operational amplifier U1, and one end of resistor R5. The other end of resistor R5 is connected to the output terminal of operational amplifier U2 and one end of resistor R7. The other end of resistor R7 is connected to the inverting input terminal of operational amplifier U2 and one end of resistor R8. The non-inverting input terminal of operational amplifier U2 is connected to one end of capacitor C7 and one end of resistor R6. The other end of resistor R6 is connected to the output terminal of operational amplifier U1, the fourth output terminal 352, one end of resistor R4, and one end of capacitor C6. The other end of resistor R4 is connected to the other end of resistor R3. The other end of capacitor C6 is connected to the other end of resistor R2. The non-inverting input terminal of operational amplifier U1, the other end of capacitor C7, and the other end of resistor R8 are grounded.

[0049] In the amplification unit 35, this application can amplify the signal by 133 times, enabling the detection of signals above 1mA in the circuit. Specifically, the ratio of resistor R1 to (R3+R4) can be 133 times, achieving the function of amplification by 133 times. Additionally, the DC signal is filtered out by resistor R6 and capacitor C7, then amplified by resistors R7 and R8, and finally fed back to the input of operational amplifier U1 via R5, thereby simultaneously compensating for DC deviation.

[0050] The low-frequency filter unit 36 ​​includes resistors R9, R10, R11, and R12, capacitors C8 and C9, TVS diodes D2 and D3, operational amplifier U3, and operational amplifier U4. The fifth input terminal 361 is connected to one end of resistor R9. The other end of resistor R9 is connected to one end of capacitor C8 and one end of resistor R10. The other end of capacitor C8 is connected to one end of resistor R11, the inverting input terminal of operational amplifier U4, the positive terminal of TVS diode D3, and the output terminal of operational amplifier U4. The other end of resistor R10... Connect one end of capacitor C9 to the non-inverting input of operational amplifier U4. Connect the other end of resistor R11 to one end of resistor R12 and the inverting input of operational amplifier U3. Connect the output of operational amplifier U3 to the other end of resistor R12 and the positive terminal of TVS transistor D2. Connect the negative terminals of TVS transistors D2 and D3 to the fifth output terminal 362. The inverting input of operational amplifier U3 and the other end of capacitor C9 are both grounded. It should be noted that TVS transistors D2 and D3 can both be unidirectional TVS transistors.

[0051] In the low-frequency filtering unit 36, high-frequency signals are filtered out through two stages of filtering: resistor R9 and capacitor C8, and resistor R10 and capacitor C9. Additionally, the positive signal is directly output through TVS diode D3, while the negative signal is inverted by the inverting circuit operational amplifier U3 and resistors R11 and R12, then passed through TVS diode D2 before being output, thus converting the negative AC leakage signal into a positive voltage leakage signal. Furthermore, while the normal AC frequency range is 45Hz to 60Hz, this application can retain low-frequency signals below 300Hz, filtering out high-frequency components to provide a margin and prevent leakage current from low-frequency components such as 60Hz, 120Hz, and 180Hz harmonic components.

[0052] Digital output unit 33 includes resistors R13, R14, R15, R16, and R17, capacitors C10, C11, C12, and C13, and comparator U5. The second input terminal 31 is connected to one end of resistor R13, one end of capacitor C10, one end of capacitor C11, one end of capacitor C12, and the inverting input terminal of comparator U5. The non-inverting input terminal of comparator U5 is connected to one end of resistor R14, one end of resistor R15, one end of resistor R16, and the capacitor U5. One end of C13 and the other end of resistor R16 are connected to the output of comparator U5 and one end of resistor R17, respectively. The other end of resistor R17 is connected to the second output terminal 32. The other ends of resistors R13, R15, C10, C11, C12, and C13 are all grounded. The other end of resistor R14 is connected to the preset leakage threshold, i.e., the other end of resistor R14 is connected to terminal A, which can provide a preset leakage threshold of +12V. It should be noted that comparator U5 is the first comparator 331.

[0053] It should be noted that leakage current detection typically requires control and signal processing by a corresponding MCU. MCUs are usually designed to operate within a specific low-voltage range (e.g., 3.3V or 5V). Therefore, a voltage conversion circuit can effectively adjust the external signal to a voltage range suitable for the MCU. This not only ensures the safe and stable operation of the MCU and optimizes the overall system performance and reliability, but also makes leakage current detection more accurate and efficient. Please refer to [link / reference]. Figure 5 As shown, the voltage conversion circuit includes a resistor R18, a diode D4, and a transistor Q1. The second output terminal 32 is connected to the cathode of diode D4 and the base of transistor Q1, respectively. The emitter of transistor Q1 and the anode of diode D4 are both grounded. The collector of transistor Q1 is connected to one end of resistor R18, and the other end of resistor R18 is connected to the first power supply voltage, i.e., the other end of resistor R18 is connected to terminal B, which can provide a +5V voltage. The connection node between resistor R18 and transistor Q1 is connected to the MCU to transmit the corresponding signal to the MCU. It should be noted that the first power supply voltage is the voltage suitable for the MCU and is also the voltage converted by the voltage conversion circuit.

[0054] Please see Figure 3As shown, in some embodiments, the signal processing circuit 30 further includes a sixth output terminal 37, which is configured to output a status signal. The status signal output by the sixth output terminal 37 is an analog signal. The signal processing circuit 30 also includes an analog output unit 38, which is connected to the second input terminal 31 and the sixth output terminal 37 respectively. The analog output unit 38 includes a first resistor, a second capacitor, and a second TVS diode. One end of the first resistor is connected to the second input terminal 31, and the second capacitor and the second TVS diode are connected in parallel between the other end of the first resistor and the sixth output terminal 37.

[0055] Please see Figure 3 and Figure 5 As shown, for example, the analog output unit 38 includes a resistor R19, a capacitor C14, and a TVS diode D5, wherein the resistor R19 is the first resistor, the capacitor C14 is the second capacitor, and the TVS diode D5 is the second TVS diode. One end of the resistor R19 is connected to the first output terminal 22, and one end of the capacitor C14 and one end of the TVS diode D5 are both connected to the other end of the resistor R19 and the sixth output terminal 37. The other ends of the capacitor C14 and the other ends of the TVS diode D5 are both grounded.

[0056] Analog output unit 38 processes the power signal after it has been processed by the leakage current filtering unit. The combination of resistors and capacitors effectively filters out high-frequency noise and improves signal integrity. The TVS diode provides protection against transient overvoltages, preventing circuit damage due to voltage spikes. This helps improve circuit stability and ensures that the signal is not affected by external interference during transmission. It should be noted that the sixth output terminal 37 can be connected to an MCU, allowing the MCU to receive analog signals sent by analog output unit 38. The analog signal is sent to the MCU's analog-to-digital converter port. The MCU can set the leakage current signal threshold value via software, and can also adjust the software-detected leakage current threshold value.

[0057] It should be noted that in this embodiment, the MCU can simultaneously receive both analog and digital signals. The leakage signal is determined by judging these dual signals. This dual hardware and software error detection mechanism allows us to avoid false alarms in some abnormal situations, such as lightning surge signals. By distinguishing between surge signals and leakage signals, we can filter out lightning surge signals while simultaneously identifying normal vehicle leakage signals.

[0058] Please see Figure 4As shown, in some embodiments, the detection device 10 has a first detection terminal 11, a second detection terminal 12, and a detection output terminal 14, with the detection output terminal 14 connected to the first input terminal 21; the leakage current detection system further includes a self-test circuit 40, which includes an AC self-test unit 41. The AC self-test unit 41 has a first self-test input terminal 411, a second self-test input terminal 412, a first self-test output terminal 413, and a second self-test output terminal 414. The first self-test input terminal 411 is configured to input a first detection square wave signal, the second self-test input terminal 412 is configured to input a second detection square wave signal, the first self-test output terminal 413 is connected to the first detection terminal 11, and is configured to transmit the first detection square wave signal to the first detection terminal 11. The second self-test output terminal 414 is connected to the second detection terminal 12, and is configured to transmit the second detection square wave signal to the second detection terminal 12. The first and second detection square wave signals are opposite.

[0059] Please see Figure 4 and Figure 5 As shown, exemplarily, the AC self-test unit 41 includes resistors R20, R21, R22, R23, R24, and R25, capacitor C15, transistor Q2, and transistor Q3. One end of resistor R22 is connected to the first self-test input terminal 411, and the other end of resistor R22 is connected to one end of resistor R23 and the base of transistor Q2. The emitter of transistor Q2 and the other end of resistor R23 are both grounded, and the collector of transistor Q2 is connected to the first self-test output terminal. Terminal 413 and one end of resistor R20 are connected to the second self-test input terminal 412. One end of resistor R24 ​​is connected to one end of resistor R25 and the base of transistor Q3. The emitter of transistor Q3 and the other end of resistor R25 are both grounded. The collector of transistor Q3 is connected to the second self-test output terminal 414 and one end of resistor R21. The other end of resistor R20, the other end of resistor R20, and one end of capacitor C15 are connected to terminal C, which can provide a +5V voltage. Resistors R22 and R23, along with transistor Q2, form an NPN digital transistor with integrated resistors. Resistors R24 and R25, along with transistor Q3, also form an NPN digital transistor with integrated resistors. Additionally, terminals P1 and P2 are the first detection terminal 11 and the second detection terminal 12, respectively. Terminal P3 is grounded, and terminal P4 is the detection output terminal 14.

[0060] Understandably, the first and second detection square wave signals need to meet specific frequencies and amplitudes to simulate leakage current. The first and second detection square wave signals are opposite in direction to generate alternating currents in opposite directions within the detection device 10, thus simulating an AC leakage current signal. This simulated AC leakage current signal can be generated by the MCU; that is, the first and second detection square wave signals originate from the MCU. After being loaded onto the detection device 10 as a simulated AC leakage current signal, they pass through the leakage current filtering circuit 20 and the signal processing circuit 30, outputting a status signal characterizing the leakage current detection result to the MCU. If the MCU receives the status signal corresponding to the leakage current, the leakage current detection system is confirmed to be functioning normally. If the MCU does not receive the status signal, it indicates an abnormality in the leakage current detection system, requiring repair or replacement. Through the self-test circuit, the system can perform self-diagnosis, improving overall reliability and ensuring timely response when actual leakage current occurs. It should be noted that the first and second detection square wave signals can be used to load the simulated AC leakage current signal onto the detection device 10 via corresponding self-test wires.

[0061] Please see Figure 5 As shown, the leakage current detection system of this application embodiment will be described exemplarily below: First, the self-test circuit 40 checks and confirms whether the leakage current detection system is functioning normally; if the leakage current detection system is functioning normally, the detection device 10 detects the power signal on the power line. The detection device 10 outputs the detected power signal through its output terminal to the leakage current filtering circuit 20. After filtering out high-frequency noise and transient voltage spikes, one branch signal of the leakage current filtering circuit 20 enters the noise filtering unit 34 to filter out the preset noise signal in the power signal. Then, the power signal is amplified to a preset multiple by the amplification unit 35. After that, the preset high-frequency signal of the power signal is filtered out by the low-frequency filtering unit 36. Finally, the status signal is output as a digital signal by the digital output unit 33. After filtering out high-frequency noise and transient voltage spikes, another branch signal of the leakage current filtering circuit 20 is output as an analog signal by the analog output unit 38. Then, the power line leakage current is determined by at least one of the digital signal or the analog signal.

[0062] like Figure 6 As shown, correspondingly, this application embodiment also provides a leakage current sensor 50, including the leakage current detection system in the above embodiment.

[0063] In this application, the leakage current sensor 50 is based on the AC self-test unit 41 included in the leakage current detection system, and the leakage current sensor 50 can perform AC leakage current self-test. For example, Figure 6In this circuit, port IN1 refers to the first self-test input terminal 411 of the leakage current detection system, port IN2 refers to the second self-test input terminal 412 of the leakage current detection system, and OUT1 refers to the second output terminal 32 or the sixth output terminal 37. Furthermore, the MCU can send a first detection square wave signal and a second detection square wave signal with opposite signals to ports IN1 and IN2. After passing through the detection device 10, the leakage current filter circuit 20, and the signal processing circuit 30, a status signal characterizing the leakage current detection result is output to the MCU. If the MCU receives the status signal corresponding to the leakage current, it confirms that the leakage current sensor 50 is functioning normally. If the MCU cannot receive the status signal corresponding to the leakage current, it indicates that the leakage current sensor 50 is malfunctioning and needs to be repaired or replaced. Thus, the leakage current sensor 50 can realize AC leakage current detection.

[0064] In addition, the leakage current sensor 50 can also integrate DC leakage current detection functionality, that is, adding a corresponding DC leakage current detection circuit to the leakage current sensor. This circuit can sense and process changes in DC current, thereby identifying DC leakage current conditions. The corresponding DC leakage current detection circuit may include a DC self-test function. For example, Figure 6 Port IN3 refers to the DC leakage current self-test input terminal, and port OUT2 refers to the DC leakage current self-test output terminal. The MCU can then send an analog DC leakage current signal to port IN3. The corresponding DC leakage current detection circuit will then output a status signal representing the DC leakage current detection result back to the MCU. If the MCU receives the status signal corresponding to the DC leakage current, the leakage current sensor 50 is confirmed to be functioning normally. If the MCU does not receive the status signal, the leakage current sensor 50 is malfunctioning and requires repair or replacement. The MCU can use the same physical port to send different types of signals, such as an analog DC leakage current signal or a first detection square wave signal. The MCU's internal settings and control logic can switch between different signal types according to current needs. Figure 6 As shown, the analog DC leakage signal output by the MCU can enter port IN3 after passing through resistor R, which can realize multiple functions such as signal conditioning and protection, ensuring the stability, compatibility and adaptability of the circuit.

[0065] It should be noted that the DC leakage current detection circuit and the AC leakage current detection circuit can each correspond to a separate detection coil, or they can share a single coil. Furthermore, the analog DC leakage current signal can be applied to the detection coil of the DC leakage current detection circuit via a corresponding self-test wire.

[0066] It is understood that the leakage current sensor in the embodiments of this application can be a sensor that detects AC leakage current alone, or it can be a sensor that detects AC or DC leakage current. In addition, the leakage current sensor can have all the technical features and technical effects of the above-mentioned leakage current detection system, which will not be repeated here.

[0067] Accordingly, this application embodiment also provides a control board, including: a leakage current sensor as described in the above embodiment; a circuit board, the circuit board being detachably connected to the leakage current sensor; and a relay, detachably connected to the circuit board, the relay having a first power input terminal, a second power input terminal, a first power output terminal, and a second power output terminal, the first power input terminal being configured to be connected to a power line, the second power input terminal being configured to be connected to the circuit board, the first power output terminal being configured to be connected to the circuit board, the second power output terminal being configured to be connected to the detection device 10, and the current of the first power output terminal being lower than the current of the second power output terminal.

[0068] Please see Figure 7 As shown, a switch is provided between the second power input terminal and the second power output terminal to control the on / off state of the relay. The first power input terminal includes terminals A1 and B1, the second power input terminal includes terminals A2 and B2, the first power output terminal includes terminals A4 and B4, and the second power output terminal includes terminals A3 and B3. It can be understood that the first power input terminal is connected to the power cord to provide initial power input, and the switch connects the second power input terminal and the first power output terminal. This allows current to be supplied to the circuit board based on the connection between the second power input terminal and the second power output terminal, and also allows power to be supplied to other devices based on the first power output terminal. Furthermore, because the circuit board load is relatively small, the current at the first power output terminal is lower than the current at the second power output terminal. In this application, the power cord is directly soldered to the relay instead of the circuit board. This design saves space on the circuit board and improves the compactness and efficiency of the overall layout.

[0069] It is important to understand that, in order to adapt to the needs of different application scenarios, the relay and detection device 10 can be detachably connected to the circuit board. This means that only the specifications of the relay need to be changed, which can simultaneously meet the requirements of 10A, 16A, 32A, 40A, etc. The leakage current sensor can also be replaced with different ones to meet the functional requirements of AC leakage current, DC leakage current, etc. Furthermore, a detachable connection can be achieved through a fisheye pin, which can be directly inserted into the circuit board, eliminating the need for soldering.

[0070] It is understandable that the control board can have all the technical features and effects of the aforementioned leakage current detection system, which will not be elaborated here.

[0071] Accordingly, this application also provides an electrical device, including the control board described in the above embodiments. It is understood that the electrical device can possess all the technical features and effects of the aforementioned leakage current detection system, which will not be elaborated upon here. It should be noted that the electrical device can be a charging gun or similar device.

[0072] The above provides a detailed description of a leakage current detection system, leakage current sensor, and control board provided by this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An electric leakage detection system characterized by, The system comprises: a detection device (10) configured to detect and output a power signal of a power line; a leakage filtering circuit (20) having a first input end (21) and a first output end (22), the first input end (21) being connected with the detection device (10); a signal processing circuit (30) having a second input end (31) and a second output end (32), the second input end (31) being connected with the first output end (22), and the second output end (32) being configured to output a state signal used to represent a leakage detection result.

2. The leakage detection system according to claim 1, wherein: the leakage filtering circuit (20) comprises a first capacitor and a first TVS tube, and the first capacitor and the first TVS tube are connected in parallel between the first input end (21) and the first output end (22).

3. The electric leakage detection system of claim 1, wherein, the state signal output by the second output end (32) is a digital signal; and the signal processing circuit (30) comprises: a digital output unit (33) comprising a first comparator (331) having a first end (3311), a second end (3312) and a third end (3313), the first end (3311) being connected with the second input end (31), the second end (3312) being configured to input a preset leakage threshold value, and the third end (3313) being connected with the second output end (32).

4. The electric leakage detection system of claim 3, wherein, the signal processing circuit (30) further comprises: a noise filtering unit (34) having a third input end (341) and a third output end (342), the third input end (341) being connected with the first output end (22), and the third output end (342) being connected with the first end (3311), and the noise filtering unit (34) being configured to filter out a preset noise signal in the power signal.

5. The electric leakage detection system of claim 3, wherein, the signal processing circuit (30) further comprises: an amplification unit (35) having a fourth input end (351) and a fourth output end (352), the fourth input end (351) being connected with the first output end (22), and the fourth output end (352) being connected with the first end (3311), and the amplification unit (35) being configured to amplify the power signal to a preset multiple.

6. The leakage detection system according to claim 3, wherein: the signal processing circuit (30) further comprises: a low-frequency filtering unit (36) having a fifth input end (361) and a fifth output end (362), the fifth input end (361) being connected with the first output end (22), and the fifth output end (362) being connected with the first end (3311), and the low-frequency filtering unit (36) being configured to filter out a preset high-frequency signal in the power signal.

7. The electric leakage detection system of claim 1, wherein, the signal processing circuit (30) further comprises a sixth output end (37) configured to output the state signal, and the state signal output by the sixth output end (37) is an analog signal. The signal processing circuit (30) further comprises: An analog output unit (38) connected to the second input end (31) and the sixth output end (37) respectively, the analog output unit (38) comprising a first resistor, a second capacitor and a second TVS tube, one end of the first resistor being connected to the second input end (31), the second capacitor and the second TVS tube being connected in parallel between the other end of the first resistor and the sixth output end (37).

8. The electrical leakage detection system of claim 1, wherein, The detection device (10) has a first detection end (11), a second detection end (12) and a detection output end (14), the detection output end (14) being connected to the first input end (21); The leakage detection system further comprises: A self-checking circuit (40), the self-checking circuit (40) comprising an alternating current self-checking unit (41), the alternating current self-checking unit (41) having a first self-checking input end (411), a second self-checking input end (412), a first self-checking output end (413) and a second self-checking output end (414), the first self-checking input end (411) being configured to input a first detection square wave signal, the second self-checking input end (412) being configured to input a second detection square wave signal, the first self-checking output end (413) being connected to the first detection end (11), the first self-checking output end (413) being configured to transmit the first detection square wave signal to the first detection end (11), the second self-checking output end (414) being connected to the second detection end (12), the second self-checking output end (414) being configured to transmit the second detection square wave signal to the second detection end (12), the first detection square wave signal and the second detection square wave signal being opposite.

9. An electric leakage sensor characterized by comprising: Comprise: The leakage detection system according to any one of claims 1 to 8.

10. A control panel, characterized by Comprise: The leakage sensor according to claim 9; A circuit board, the circuit board being detachably connected to the leakage sensor; A relay, the relay being detachably connected to the circuit board, the relay having a first power input end, a second power input end, a first power output end and a second power output end, the first power input end being configured to be connected to a power line, the second power input end being configured to be connected to the circuit board, the first power output end being configured to be connected to the circuit board, the second power output end being configured to be connected to the leakage sensor, the current of the first power output end being lower than the current of the second power output end.

Images