Appliance detection circuit and appliance protection device

Abstract

The utility model relates to an electric appliance detection circuit and electric appliance protection device, and the electric appliance detection circuit includes leakage current sensor, relay control unit and adhesion detection module, leakage current sensor is in series on the fire line and zero line, relay control unit includes first relay and second relay, and first relay is in series on the fire line, and second relay is in series on the zero line, adhesion detection module has first voltage input, second voltage input, first voltage output and second voltage output, and first voltage input and second voltage input are electrically connected on the fire line and zero line, and two first voltage outputs are connected. The utility model can identify first relay and second relay fault in time through adhesion detection module, prevents first relay and second relay protection invalidity due to adhesion, and improves the security of electric appliance detection circuit.

Description

Technical Field

[0001] This utility model relates to the field of electrical safety technology, specifically to an electrical detection circuit and an electrical protection device. Background Technology

[0002] Residual current protection (RCD) is a crucial safety measure in electrical systems, used to promptly cut off power in the event of a leakage current, preventing electric shock and electrical fires. Existing electrical detection circuits typically include leakage current sensors and relay control units, capable of detecting leakage current between the live and neutral wires and controlling circuit continuity. However, relays are prone to contact sticking under frequent switching or overload conditions, preventing them from disconnecting properly and thus rendering them ineffective. Utility Model Content

[0003] Based on the above description, this utility model provides an electrical detection circuit and an electrical protection device, aiming to solve the problem that existing electrical detection circuits cannot identify relay contact sticking.

[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: In a first aspect, an electrical appliance detection circuit includes: A leakage current sensor is connected in series with the live wire and the neutral wire. The signal output terminal of the leakage current sensor is used to connect to the control module. The leakage current sensor is configured to detect the power supply current of the live wire and the power supply current of the neutral wire. The relay control unit includes a first relay and a second relay. The first relay is connected in series with the live wire and is configured to control the on / off state of the live wire. The second relay is connected in series with the neutral wire. The controlled terminals of the first relay and the second relay are both used to connect to the control module. The second relay is configured to control the on / off state of the neutral wire. The adhesion detection module has a first voltage input terminal, a second voltage input terminal, a first voltage output terminal, and a second voltage output terminal. The first voltage input terminal and the second voltage input terminal are electrically connected to the live wire and the neutral wire. The two first voltage output terminals are connected and used to connect to the control module. The adhesion detection module is configured to detect the power supply voltage of the live wire and the neutral wire.

[0005] Based on the above technical solution, the present invention can be further improved as follows.

[0006] Furthermore, the adhesion detection module includes a first resistor, an optocoupler, and a second resistor. One end of the first resistor serves as the first voltage input terminal. The first and second pins of the optocoupler are electrically connected to one end of the second resistor and the other end of the first resistor, respectively. The third pin of the optocoupler serves as the first voltage output terminal, the fourth pin of the optocoupler serves as the second voltage output terminal, and the other end of the second resistor serves as the second voltage input terminal.

[0007] Furthermore, the adhesion detection module includes a capacitor connected in parallel between the third and fourth pins of the optocoupler.

[0008] Furthermore, it includes a ground fault detection module, which includes a sampling input terminal, a sampling ground terminal, and a sampling output terminal. The sampling input terminal is electrically connected to the live wire, the sampling ground terminal is grounded, and the sampling output terminal is used to connect to the control module. The ground fault detection module is configured to collect the power supply voltage of the live wire to obtain the collected voltage.

[0009] Furthermore, the ground fault detection module includes a rectifier diode and a voltage divider circuit. The positive terminal of the rectifier diode serves as the sampling input terminal, the input terminal of the voltage divider circuit is electrically connected to the negative terminal of the rectifier diode, the ground terminal of the voltage divider circuit serves as the sampling ground terminal, and the output terminal of the voltage divider circuit serves as the sampling output terminal.

[0010] Furthermore, the ground fault detection module includes a clamping diode, the positive terminal of which is electrically connected to the ground terminal of the voltage divider circuit, and the negative terminal of which is electrically connected to the output terminal of the voltage divider circuit.

[0011] Furthermore, it includes an NTC thermistor, one end of which is electrically connected to the ground terminal of the voltage divider circuit, and the other end of which is used to connect to the control module. The NTC thermistor is configured to collect the operating temperature of the first relay.

[0012] Furthermore, it includes a current transformer connected in series with the neutral line, the two signal output terminals of the current transformer being used to connect to the control module, and the current transformer being configured to detect the output current of the neutral line.

[0013] In a second aspect, an electrical protection device includes the electrical detection circuit described in the first aspect.

[0014] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: (1) This utility model can promptly identify the faults of the first and second relays through the adhesion detection module, prevent the first and second relays from failing due to adhesion, and improve the safety of the electrical detection circuit.

[0015] (2) This utility model detects the voltage difference between the live wire and the ground wire through the ground fault detection module, which can prevent electric shock, false alarms of leakage current sensor, and other problems.

[0016] (3) The NTC thermistor of this utility model realizes the temperature monitoring function, which can provide early warning of the risk of overheating of the first relay and prevent the first relay from failing or causing a fire due to excessive temperature. Attached Figure Description

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

[0018] Figure 1 This is a circuit diagram of an electrical detection circuit provided in an embodiment of the present utility model.

[0019] Explanation of reference numerals in the attached figures: 1. Live wire; 2. Neutral wire; 10. Leakage current sensor; 20. Relay control unit; 21. First relay; 22. Second relay; 30. Adhesion detection module; 31. First resistor; 32. Optocoupler; 33. Second resistor; 34. Capacitor; 40. Grounding fault detection module; 41. Voltage divider circuit; 42. Rectifier diode; 43. Clamping diode; 50. NTC thermistor; 60. Current transformer. Detailed Implementation

[0020] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0022] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "above," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "below" of the other element or feature will be oriented "above" the other element or feature. Therefore, the exemplary terms "below" and "below" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0023] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0024] Reference Figure 1As shown, this utility model provides a technical solution: an electrical detection circuit, including a leakage current sensor 10, a relay control unit 20, and an adhesion detection module 30; the leakage current sensor 10 is connected in series with the live wire 1 and the neutral wire 2, and the signal output terminal of the leakage current sensor 10 is used to connect to the control module. The leakage current sensor 10 is configured to detect the power current of the live wire 1 and the power current of the neutral wire 2; the relay control unit 20 includes a first relay 21 and a second relay 22, the first relay 21 is connected in series with the live wire 1, and the first relay 21 is configured to control the power supply of the live wire 1. The second relay 22 is connected in series with the neutral wire 2. The controlled terminals of the first relay 21 and the second relay 22 are both used to connect to the control module. The second relay 22 is configured to control the on / off state of the neutral wire 2. The adhesion detection module 30 has a first voltage input terminal, a second voltage input terminal, a first voltage output terminal, and a second voltage output terminal. The first voltage input terminal and the second voltage input terminal are electrically connected to the live wire 1 and the neutral wire 2. The two first voltage output terminals are connected and used to connect to the control module. The adhesion detection module 30 is configured to detect the power supply voltage of the live wire 1 and the power supply voltage of the neutral wire 2.

[0025] In this embodiment, the leakage current sensor 10 identifies leakage by detecting the current difference between the live wire 1 and the neutral wire 2. When the live wire 1 and the neutral wire 2 are working normally, the leakage current sensor 10 outputs a low level to the control module. When leakage current occurs between the live wire 1 and the neutral wire 2, the leakage current sensor 10 outputs a high level to the control module. When the control module determines that leakage exists based on the leakage current signal, it sends a control signal to disconnect the first relay 21 and the second relay 22, thereby cutting off the power supply. The adhesion detection module 30 feeds back the power supply voltage of the live wire 1 and the neutral wire 2 to the control module, allowing the control module to determine whether the first relay 21 and the second relay 22 are disconnected based on these voltages. The adhesion detection module 30 can promptly identify faults in the first relay 21 and the second relay 22, preventing the first relay 21 and the second relay 22 from failing due to adhesion, thus improving the safety of the electrical detection circuit.

[0026] Reference Figure 1 As shown, in some embodiments, the adhesion detection module 30 includes a first resistor 31, an optocoupler 32, and a second resistor 33. One end of the first resistor 31 serves as a first voltage input terminal. The first and second pins of the optocoupler 32 are electrically connected to one end of the second resistor 33 and the other end of the first resistor 31 in a one-to-one correspondence. The third pin of the optocoupler 32 serves as a first voltage output terminal, the fourth pin of the optocoupler 32 serves as a second voltage output terminal, and the other end of the second resistor 33 serves as a second voltage input terminal.

[0027] In this embodiment, when both relays are closed, current flows through the first and second pins of optocoupler 32, causing the diode of optocoupler 32 to light up and the transistor of optocoupler 32 to close, allowing the control module to receive the power supply voltage of live wire 1 and neutral wire 2. When the first relay 21 or the second relay 22 is open, no current flows through the first or second pin of optocoupler 32, causing the diode of optocoupler 32 to not light up and the transistor of optocoupler 32 to open, preventing the control module from receiving the power supply voltage of live wire 1 or neutral wire 2. That is, if the control module can still receive the power supply voltage of live wire 1 and neutral wire 2 when the two relays are opened by the control module, it is determined that the two relays are stuck together, thus enabling the detection of the sticking of the two relays.

[0028] Reference Figure 1 As shown, in some embodiments, the adhesion detection module 30 includes a capacitor 34, which is connected in parallel between the third and fourth pins of the optocoupler 32.

[0029] In this embodiment, capacitor 34 serves to filter and stabilize the output power voltage of optocoupler 32. When optocoupler 32 outputs power voltage, capacitor 34 can absorb instantaneous fluctuations, reduce noise interference, and ensure the stability of the output power voltage.

[0030] Reference Figure 1 As shown, in some embodiments, the electrical detection circuit includes a ground fault detection module 40. The ground fault detection module 40 includes a sampling input terminal, a sampling ground terminal, and a sampling output terminal. The sampling input terminal is electrically connected to the live wire 1, the sampling ground terminal is grounded, and the sampling output terminal is used to connect to the control module. The ground fault detection module 40 is configured to collect the power supply voltage of the live wire 1 to obtain the collected voltage.

[0031] In this embodiment, the ground fault detection module 40 feeds back the power supply voltage of the live wire 1 to the control module, enabling the control module to determine whether the electrical detection circuit has been successfully grounded. Specifically, after the control module controls the first relay 21 and the second relay 22 to close, when the GND grounding is normal, current flows through the live wire 1, and the ground fault detection module 40 collects the voltage and sets the collected voltage to a low level. When there is a GND contact fault, no current flows through the load circuit, resulting in an open circuit, and the ground fault detection module 40 collects the voltage and sets it to a high level. The control module determines whether the electrical detection circuit is in normal working condition based on the low or high voltage level.

[0032] Reference Figure 1As shown, in some embodiments, the ground fault detection module 40 includes a rectifier diode 42 and a voltage divider circuit 41. The positive terminal of the rectifier diode 42 serves as the sampling input terminal, the input terminal of the voltage divider circuit 41 is electrically connected to the negative terminal of the rectifier diode 42, the ground terminal of the voltage divider circuit 41 serves as the sampling ground terminal, and the output terminal of the voltage divider circuit 41 serves as the sampling output terminal.

[0033] In this embodiment, when GND is properly grounded, current flows through the load circuit. The rectifier diode 42 receives the collected voltage and converts the AC to DC, which is then divided by the voltage divider circuit 41 to make the collected voltage low. When GND is faulty, no current flows through the load circuit, which is an open circuit. The rectifier diode 42 receives the collected voltage and converts the AC to DC, which is then divided by the voltage divider circuit 41 to make the collected voltage high. The control module determines whether the electrical detection circuit is operating normally based on the low or high voltage level.

[0034] Reference Figure 1 As shown, in some embodiments, the ground fault detection module 40 includes a clamping diode 43, the positive terminal of which is electrically connected to the ground terminal of the voltage divider circuit 41, and the negative terminal of which is electrically connected to the output terminal of the voltage divider circuit 41.

[0035] In this embodiment, when the sampling voltage output by the voltage divider circuit 41 exceeds a certain value, the clamping diode 43 is turned on to limit the sampling voltage within a safe range and prevent overvoltage from damaging the control module.

[0036] Reference Figure 1 As shown, in some embodiments, the electrical detection circuit includes an NTC thermistor 50, one end of which is electrically connected to the ground terminal of the voltage divider circuit 41, and the other end of which is used to connect to the control module. The NTC thermistor 50 is configured to collect the operating temperature of the first relay 21.

[0037] In this embodiment, the resistance value of the NTC thermistor 50 changes with temperature. The control module indirectly obtains the temperature of the relay by measuring the resistance or voltage value. If the temperature is too high, it indicates that the first relay 21 may be overloaded or malfunctioning. This achieves the temperature monitoring function, which can provide early warning of the risk of overheating of the first relay 21 and prevent the first relay 21 from failing or catching fire due to excessive temperature.

[0038] Reference Figure 1 As shown, in some embodiments, the electrical detection circuit includes a current transformer 60 connected in series with the neutral line 2. The two signal output terminals of the current transformer 60 are used to connect to the control module. The current transformer 60 is configured to detect the output current of the neutral line 2.

[0039] In this embodiment, the current transformer 60 detects the output current of the neutral wire 2 and converts the current signal into a voltage or digital signal for processing by the control module, thereby realizing current monitoring of the neutral wire 2. By detecting the current of the neutral wire 2, current imbalance or other abnormalities can be identified.

[0040] This utility model provides a technical solution: an electrical protection device, including the above-mentioned electrical detection circuit.

[0041] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An electrical appliance detection circuit, characterized in that, include: A leakage current sensor (10) is connected in series with the live wire (1) and the neutral wire (2). The signal output terminal of the leakage current sensor (10) is used to connect to the control module. The leakage current sensor (10) is configured to detect the power supply current of the live wire (1) and the power supply current of the neutral wire (2). The relay control unit (20) includes a first relay (21) and a second relay (22). The first relay (21) is connected in series with the live wire (1) and is configured to control the on / off state of the live wire (1). The second relay (22) is connected in series with the neutral wire (2). The controlled terminals of the first relay (21) and the second relay (22) are both used to connect to the control module. The second relay (22) is configured to control the on / off state of the neutral wire (2). The adhesion detection module (30) has a first voltage input terminal, a second voltage input terminal, a first voltage output terminal and a second voltage output terminal. The first voltage input terminal and the second voltage input terminal are electrically connected to the live wire (1) and the neutral wire (2). The two first voltage output terminals are connected and used to access the control module. The adhesion detection module (30) is configured to detect the power supply voltage of the live wire (1) and the neutral wire (2).

2. The electrical detection circuit according to claim 1, characterized in that, The adhesion detection module (30) includes a first resistor (31), an optocoupler (32), and a second resistor (33). One end of the first resistor (31) serves as the first voltage input terminal. The first and second pins of the optocoupler (32) are electrically connected to one end of the second resistor (33) and the other end of the first resistor (31) in a one-to-one correspondence. The third pin of the optocoupler (32) serves as the first voltage output terminal. The fourth pin of the optocoupler (32) serves as the second voltage output terminal. The other end of the second resistor (33) serves as the second voltage input terminal.

3. The electrical detection circuit according to claim 2, characterized in that, The adhesion detection module (30) includes a capacitor (34), which is connected in parallel between the third and fourth pins of the optocoupler (32).

4. The electrical detection circuit according to claim 1, characterized in that, The system includes a ground fault detection module (40), which includes a sampling input terminal, a sampling ground terminal and a sampling output terminal. The sampling input terminal is electrically connected to the live wire (1), the sampling ground terminal is grounded, and the sampling output terminal is used to connect to the control module. The ground fault detection module (40) is configured to collect the power supply voltage of the live wire (1) to obtain the collected voltage.

5. The electrical detection circuit according to claim 4, characterized in that, The ground fault detection module (40) includes a rectifier diode (42) and a voltage divider circuit (41). The positive terminal of the rectifier diode (42) serves as the sampling input terminal. The input terminal of the voltage divider circuit (41) is electrically connected to the negative terminal of the rectifier diode (42). The ground terminal of the voltage divider circuit (41) serves as the sampling ground terminal. The output terminal of the voltage divider circuit (41) serves as the sampling output terminal.

6. The electrical detection circuit according to claim 5, characterized in that, The ground fault detection module (40) includes a clamping diode (43), the positive terminal of which is electrically connected to the ground terminal of the voltage divider circuit (41), and the negative terminal of which is electrically connected to the output terminal of the voltage divider circuit (41).

7. The electrical detection circuit according to claim 5, characterized in that, The device includes an NTC thermistor (50), one end of which is electrically connected to the ground terminal of the voltage divider circuit (41), and the other end of which is used to connect to the control module. The NTC thermistor (50) is configured to collect the operating temperature of the first relay (21).

8. The electrical detection circuit according to claim 1, characterized in that, Includes a current transformer (60), which is connected in series with the neutral line (2). The two signal output terminals of the current transformer (60) are used to connect to the control module. The current transformer (60) is configured to detect the output current of the neutral line (2).

9. An electrical protection device, characterized in that, Includes the electrical detection circuit according to any one of claims 1 to 8.

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