Leakage detection circuit and air conditioner

Abstract

The application provides an electric leakage detection circuit and an air conditioner. The electric leakage detection circuit comprises a sampling module and an electric leakage detection module. The sampling module is connected to a power supply to be detected, and the electric leakage detection module is connected to the sampling module. The sampling module outputs a sampling voltage according to the current of the power supply to be detected. Then, the electric leakage detection module outputs an electric leakage detection signal according to the sampling voltage and a preset reference voltage. Thus, the electric leakage of the equipment can be detected, and the electric leakage can be found in time, so that the safety of the equipment is improved.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a leakage current detection circuit and an air conditioner. Background Technology

[0002] Floor-standing air conditioners differ from wall-mounted air conditioners. Wall-mounted units can be fixed in a high place where people are not easily touched, while floor-standing units are mostly placed in a position where people can reach them.

[0003] When a leakage occurs, the metal casing, control panel, and other easily accessible parts of the air conditioner will become electrified. Daily activities such as adjusting the temperature buttons, cleaning with a damp cloth, children curiously touching crevices or exploring with metal toys, or even accidentally touching the air conditioner while standing on a damp floor after mopping, can create a current path and cause electric shock. Mild electric shocks can cause numbness and tingling; moderate shocks can lead to muscle spasms, electrical burns at the contact site, and dizziness, falls, and potential fractures; if the current exceeds 50mA and the contact time exceeds 3 seconds, it can cause fatal consequences such as cardiac arrest and respiratory paralysis. Therefore, air conditioners pose a leakage hazard and can cause electric shock at any time during daily contact, representing a hidden threat to household electrical safety. Utility Model Content

[0004] This application provides a leakage current detection circuit and an air conditioner, which can detect leakage current in the equipment, detect leakage current in a timely manner, and improve the safety of the equipment.

[0005] This application provides a leakage current detection circuit, which includes: a sampling module connected to the power supply under test, used to output a sampling voltage based on the current of the power supply under test; and a leakage current detection module connected to the sampling module, used to output a leakage current detection signal based on the sampling voltage and a preset reference voltage.

[0006] In some embodiments, the leakage current detection circuit further includes: a reference voltage generation module, the reference voltage generation module being connected to the leakage current detection module, the reference voltage generation module being used to provide the preset reference voltage to the leakage current detection module; the leakage current detection module being used to output a first detection signal when the sampled voltage is greater than or less than the preset reference voltage, and to output a second detection signal when the sampled voltage is equal to the preset reference voltage.

[0007] In some embodiments, the sampling module includes: a sensing unit connected to the power supply under test, used to sense the current input to the power supply under test to obtain an induced current; and a sampling unit connected to the sensing unit, used to convert the induced current into the sampling voltage.

[0008] In some embodiments, the sampling unit includes a first inductor and a first capacitor; a first end of the first inductor is connected to the sensing unit, a second end of the first inductor is connected to both the first end of the first capacitor and the sensing unit, and a second end of the first capacitor is connected to the leakage detection module.

[0009] In some embodiments, the reference voltage generation module includes: a voltage divider unit connected to a first power supply, used to divide the voltage output by the first power supply to obtain a divided voltage; and a voltage regulator unit connected to the voltage divider unit and the leakage current detection module, used to regulate the divided voltage to obtain the preset reference voltage.

[0010] In some embodiments, the voltage divider unit includes a first resistor, a second resistor, and a third resistor; the first end of the first resistor is connected to the first power supply, the second end of the first resistor is simultaneously connected to the first end of the second resistor, the voltage regulator unit, and the leakage current detection module, the second end of the second resistor is simultaneously connected to the first end of the third resistor and the voltage regulator unit, and the second end of the third resistor is grounded.

[0011] In some embodiments, the voltage stabilizing unit includes a first voltage regulator; the cathode of the first voltage regulator is connected to both the voltage divider unit and the leakage current detection module, the reference terminal of the first voltage regulator is connected to the voltage divider unit, and the anode of the first voltage regulator is grounded.

[0012] In some embodiments, the leakage current detection module includes a first operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a second capacitor, and a third capacitor; the first end of the fourth resistor is simultaneously connected to the first end of the second capacitor, the sampling module, and the preset reference voltage; the second end of the second capacitor is grounded; the second end of the fourth resistor is connected to the non-inverting input of the first operational amplifier; the first end of the fifth resistor is connected to the sampling module; the second end of the fifth resistor is simultaneously connected to the inverting input of the first operational amplifier, the first end of the sixth resistor, and the first end of the third capacitor; the output end of the first operational amplifier is simultaneously connected to the second end of the sixth resistor, the second end of the third capacitor, and the first end of the seventh resistor; the second end of the seventh resistor is used to output the leakage current detection signal.

[0013] In some embodiments, the leakage current detection circuit further includes: a control module connected to the leakage current detection module, configured to receive the leakage current detection signal, and shut down the device load and issue a leakage current warning when the leakage current detection signal is a first detection signal.

[0014] Secondly, embodiments of this application provide an air conditioner that includes the leakage current detection circuit described above.

[0015] This application provides a leakage current detection circuit and an air conditioner. The leakage current detection circuit includes a sampling module and a leakage current detection module. The sampling module is connected to the power supply under test, and the leakage current detection module is connected to the sampling module. First, the sampling module outputs a sampling voltage based on the current of the power supply under test. Then, the leakage current detection module outputs a leakage current detection signal based on the sampling voltage and a preset reference voltage. This enables the detection of leakage current in the device, allowing for timely detection and improving device safety. Attached Figure Description

[0016] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0017] Figure 1 This is a structural block diagram of a leakage current detection circuit provided in an embodiment of this application; Figure 2 This is a structural block diagram of a leakage current detection circuit provided in another embodiment of this application; Figure 3 This is a structural block diagram of a sampling module provided in one embodiment of this application; Figure 4 This is a structural block diagram of a reference voltage generation module provided in one embodiment of this application; Figure 5 This is a schematic diagram of the circuit structure of a leakage current detection circuit provided in an embodiment of this application; Figure 6 This is a schematic diagram of the circuit structure of the sensing unit provided in an embodiment of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0019] 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 technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0020] Please see Figure 1 , Figure 1 This is a structural block diagram of a leakage current detection circuit provided in an embodiment of this application.

[0021] This application provides a leakage current detection circuit 100, such as... Figure 1 As shown, the leakage current detection circuit 100 includes a sampling module 10 and a leakage current detection module 20. The sampling module 10 is connected to the power supply under test 200, and the leakage current detection module 20 is connected to the sampling module 10. Specifically, the sampling module 10 outputs a sampling voltage based on the current of the power supply under test 200, and the leakage current detection module 20 outputs a leakage current detection signal based on the sampling voltage and a preset reference voltage.

[0022] The power supply under test 200 is the input power supply of the device (such as an air conditioner) that needs to be tested for leakage current. The power supply under test 200 can be AC ​​power, such as mains power, and has a live wire and a neutral wire.

[0023] The sampling voltage is a voltage signal obtained by the sampling module 10 after collecting and converting the current of the power supply 200 under test. Its magnitude is related to the leakage current of the power supply 200 under test (e.g., the larger the leakage current, the higher the sampling voltage), and is used to indirectly reflect the strength of the leakage current.

[0024] The leakage current detection signal is an electrical signal output by the leakage current detection module 20 based on the sampling voltage and the preset reference voltage. The leakage current detection signal is used to indicate the leakage current status (whether leakage current has occurred) of the device connected to the power supply under test 200.

[0025] Using the embodiments of this application, the current of the power supply 200 under test can be converted into a sampling voltage by the sampling module 10, and then the sampling voltage can be detected by the leakage detection module 20 against a preset reference voltage, thereby outputting a leakage detection signal and realizing real-time monitoring of equipment leakage.

[0026] Please see Figure 2 , Figure 2 This is a structural block diagram of a leakage current detection circuit provided in another embodiment of this application.

[0027] In some embodiments, such as Figure 2 As shown, the leakage current detection circuit 100 also includes a reference voltage generation module 30. The reference voltage generation module 30 is connected to the leakage current detection module 20. Specifically, the reference voltage generation module 30 provides a preset reference voltage to the leakage current detection module 20; the leakage current detection module 20 also outputs a first detection signal when the sampled voltage is greater than or less than the preset reference voltage, and outputs a second detection signal when the sampled voltage is equal to the preset reference voltage.

[0028] The leakage current detection signal can be either a first detection signal or a second detection signal. When the leakage current detection signal is the first detection signal, it indicates that there is a leakage current. When the leakage current detection signal is the second detection signal, it indicates that there is no leakage current.

[0029] Specifically, the reference voltage generation module 30 is also connected to the first power supply (not shown in the figure, the connection point is...). Figure 2 (VDD in the diagram). The first power supply is a DC power supply, such as a +5V or +12V DC power supply. The reference voltage generation module 30 processes the voltage input from the first power supply to output a preset reference voltage. The preset reference voltage is greater than 0 and less than the voltage of the first power supply. That is, 0 < preset reference voltage < the voltage of the first power supply. For example, the voltage of the first power supply can be +5V, and the preset reference voltage can be 2.5V.

[0030] In some embodiments, such as Figure 2 As shown, the leakage current detection circuit 100 also includes a control module 40. The control module 40 is connected to the leakage current detection module 20. Specifically, the control module 40 receives leakage current detection signals, and when the leakage current detection signal is the first detection signal, shuts down the device load and issues a leakage current warning.

[0031] In this embodiment, the control module 40 judges the leakage detection signal. If the leakage detection signal is the first detection signal, it determines that there is a leakage, thereby shutting down the load of the device (the power supply under test 200 is the input power of the device) and issuing a leakage warning. The leakage warning can be issued by displaying a fault code and prompt information on the display screen, by emitting an audible warning through a speaker, or by emitting a light warning through an LED, etc.

[0032] Please see Figure 3 , Figure 3 This is a structural block diagram of a sampling module provided in one embodiment of this application.

[0033] In some embodiments, such as Figure 3 As shown, the sampling module 10 includes a sensing unit 11 and a sampling unit 12. The sensing unit 11 is connected to the power supply 200 under test, and the sampling unit 12 is connected to the sensing unit 11.

[0034] Specifically, the sensing unit 11 is used to sense the current input to the power supply 200 under test to obtain the induced current. The sampling unit 12 is used to convert the induced current into a sampling voltage.

[0035] The induced current is the current obtained by sensing the input current of the power supply 200 under test by sensing unit 11. The sampled voltage is the voltage obtained by sampling unit 12 by converting the induced current.

[0036] Please see Figure 4 , Figure 4 This is a structural block diagram of a reference voltage generation module provided in one embodiment of this application.

[0037] In some embodiments, such as Figure 4As shown, the reference voltage generation module 30 includes a voltage divider unit 31 and a voltage regulator unit 32. The voltage divider unit 31 is connected to the first power supply VDD, and the voltage regulator unit 32 is connected to both the voltage divider unit 31 and the leakage current detection module 20.

[0038] Specifically, the voltage divider unit 31 is used to divide the voltage output by the first power supply to obtain a divided voltage; the voltage regulator unit 32 is used to regulate the divided voltage to obtain a preset reference voltage.

[0039] Please refer to the following: Figure 5 and Figure 6 , Figure 5 This is a schematic diagram of the leakage current detection circuit provided in one embodiment of this application. Figure 6 This is a schematic diagram of the circuit structure of the sensing unit provided in an embodiment of this application.

[0040] In some embodiments, such as Figure 5 As shown, the sampling unit 12 includes a first inductor L1 and a first capacitor C1. The first end of the first inductor L1 is connected to the sensing unit 11, the second end of the first inductor L1 is connected to both the first end of the first capacitor C1 and the sensing unit 11, and the second end of the first capacitor C1 is connected to the leakage current detection module 20.

[0041] In some embodiments, such as Figure 6 As shown, the sensing unit 11 includes a first coil, a second coil, and a sensing magnetic ring. The first end of the first coil is connected to the live wire ACL of the power supply under test 200, and the second end of the first coil is connected to the neutral wire ACN of the power supply under test 200. The second coil and the first end are connected to the first end of the sampling unit 12 (i.e.,...). Figure 5 The first terminal of the first inductor L1 is connected to the first terminal of the second coil, and the second terminal of the second coil is connected to the second terminal of the sampling unit 12 (i.e., Figure 5 (The second terminal of the first inductor L1). Additionally, the first coil and the second coil are wound on an induction magnetic ring. The induced current is the current output by the second coil.

[0042] In some embodiments, such as Figure 5 As shown, the voltage divider unit 31 includes a first resistor R1, a second resistor R2, and a third resistor R3. The first end of the first resistor R1 is connected to the first power supply ADD. The second end of the first resistor R1 is simultaneously connected to the first end of the second resistor R2, the voltage regulator unit 32, and the leakage current detection module 20. The second end of the second resistor R2 is simultaneously connected to the first end of the third resistor R3 and the voltage regulator unit 32. The second end of the third resistor R3 is grounded.

[0043] In some embodiments, such as Figure 5As shown, the voltage regulator unit 32 includes a first voltage regulator IC1. The cathode of the first voltage regulator IC1 is connected to both the voltage divider unit 31 and the leakage current detection module 20. The reference terminal of the first voltage regulator IC1 is connected to the voltage divider unit 31, and the anode of the first voltage regulator IC1 is grounded. The second terminal of the first resistor R1 is used to output a preset reference voltage.

[0044] Among them, the first voltage regulator IC1 is a precision voltage regulator used to stabilize the voltage value of a preset reference voltage (e.g., +2.5V).

[0045] In some embodiments, such as Figure 5 As shown, the leakage current detection module 20 includes a first operational amplifier U1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a second capacitor C2, and a third capacitor C3. The first terminal of the fourth resistor R4 is simultaneously connected to the first terminal of the second capacitor C2, the sampling module 10, and a preset reference voltage. The second terminal of the second capacitor C2 is grounded. The second terminal of the fourth resistor R4 is connected to the non-inverting input terminal of the first operational amplifier U1. The first terminal of the fifth resistor R5 is connected to the sampling module 10. The second terminal of the fifth resistor R5 is simultaneously connected to the inverting input terminal of the first operational amplifier U1, the first terminal of the sixth resistor R6, and the first terminal of the third capacitor C3. The output terminal of the first operational amplifier U1 is simultaneously connected to the second terminal of the sixth resistor R6, the second terminal of the third capacitor C3, and the first terminal of the seventh resistor R7. The second terminal of the seventh resistor R7 (… Figure 5 Point A is used to output the leakage current detection signal.

[0046] In some embodiments, such as Figure 5 As shown, the control module 40 includes a chip IC2. The chip IC2 can be an MCU (Microcontroller Unit) or other devices capable of performing the same function.

[0047] In this embodiment, the leakage current detection signal can be a first detection signal or a second detection signal. The first detection signal can be a low-level signal (voltage close to 0) or a high-level signal (its voltage is equal to the voltage of the first power supply VDD), and the voltage of the second detection signal is equal to a preset reference voltage (e.g., +2.5V). The first power supply VDD can be a DC power supply such as +5V or +12V. That is, the voltage of the low-level signal < the preset reference voltage < the voltage of the high-level signal.

[0048] The following combination Figure 5 and Figure 6 The working principle of the leakage current detection circuit 100 is briefly explained.

[0049] like Figure 6As shown, the power supply under test (DUT) 200 is the input power supply for the device and is an AC power supply. DUT 200 includes a live wire (ACL) and a neutral wire (ACN). When the device (DUT 200 is the input power supply for the device) has no leakage current, the current flowing into the live wire of DUT 200 is the same as the current flowing out of the neutral wire. When the device leaks current, the current flowing into the live wire of DUT 200 is not equal to the current flowing out of the neutral wire. Therefore, when the device has no leakage current, there is no induced current in the second coil, i.e., the induced current is 0. When the device leaks current, there is an induced current in the second coil, i.e., the induced current is not 0.

[0050] like Figure 5 As shown, in the first aspect, when the induced current output by the sensing unit 11 is 0, the voltage at point FK is equal to the preset reference voltage (e.g., a +2.5V DC voltage). Simultaneously, the voltage at the first terminal of the first capacitor C1 is also equal to the preset reference voltage. At this time, according to the principle of virtual short in operational amplifiers, the voltage at the first terminal of the first capacitor C1 is the same as the voltage at the inverting input terminal of the first operational amplifier U1. Therefore, the voltage is output to the output terminal of the first operational amplifier U1 through the voltage follower formed by the sixth resistor R6. Thus, at this time, the voltage at point A is equal to the preset reference voltage (e.g., +2.5V), meaning the leakage detection signal is the second detection signal. Chip IC2 detects that the leakage detection signal is the second detection signal, thereby determining that the device (whose input power supply is the power supply under test 200) does not have a leakage phenomenon.

[0051] Secondly, when the induced current output by the sensing unit 11 is not zero, the voltage at the first terminal of the first capacitor C1 is either greater than or less than the preset reference voltage. When the voltage at the first terminal of the first capacitor C1 is greater than the preset reference voltage, the first capacitor C1 is charged, and the current flows through the first capacitor C1, the fifth resistor R5, and the sixth resistor R6 back to the ground of the first operational amplifier U1 to form a loop. At this time, point A is a low-level signal (voltage close to 0), which is the first detection signal for leakage detection. When the voltage at the first terminal of the first capacitor C1 is less than the preset reference voltage, since the voltage across the capacitor cannot change abruptly, the first capacitor C1 discharges. At this time, point A is a high-level signal (voltage equal to the voltage of the first power supply VDD, for example, +5V), which is the first detection signal for leakage detection. Chip IC2 detects that the leakage detection signal is the first detection signal, thereby determining that the device (the input power supply of the device is the power supply under test 200) has a leakage phenomenon. Chip IC2 can output a control signal (output from point B) to other components of the device to shut down the load of the device and issue a leakage warning.

[0052] This application provides a leakage current detection circuit and an air conditioner. The leakage current detection circuit 100 includes a sampling module 10 and a leakage current detection module 20. The sampling module 10 is connected to the power supply under test 200, and the leakage current detection module 20 is connected to the sampling module 10. First, the sampling module 10 outputs a sampling voltage based on the current of the power supply under test 200. Then, the leakage current detection module 20 outputs a leakage current detection signal based on the sampling voltage and a preset reference voltage. This enables the detection of leakage current in the equipment, timely detection of leakage current, and improvement of equipment safety.

[0053] This application also provides an air conditioner, which includes the above-described leakage current detection circuit 100.

[0054] It should be noted that the specific structure and working principle of the leakage current detection circuit 100 can be referred to the above embodiments, and will not be repeated here.

[0055] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0056] The leakage current detection circuit and air conditioner provided in the embodiments of this application have been described in detail above. 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 technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A leakage current detection circuit, characterized in that, The leakage current detection circuit includes: A sampling module, connected to the power supply under test, is used to output a sampling voltage based on the current of the power supply under test; A leakage current detection module, connected to the sampling module, is used to output a leakage current detection signal based on the sampling voltage and a preset reference voltage.

2. The leakage current detection circuit according to claim 1, characterized in that, The leakage current detection circuit further includes: a reference voltage generation module, which is connected to the leakage current detection module and is used to provide the preset reference voltage to the leakage current detection module; The leakage current detection module is used to output a first detection signal when the sampled voltage is greater than or less than the preset reference voltage, and to output a second detection signal when the sampled voltage is equal to the preset reference voltage.

3. The leakage current detection circuit according to claim 1, characterized in that, The sampling module includes: A sensing unit, connected to the power supply under test, is used to sense the current input to the power supply under test in order to obtain an induced current; A sampling unit, connected to the sensing unit, is used to convert the induced current into the sampling voltage.

4. The leakage current detection circuit according to claim 3, characterized in that, The sampling unit includes a first inductor and a first capacitor; The first end of the first inductor is connected to the sensing unit, the second end of the first inductor is connected to both the first end of the first capacitor and the sensing unit, and the second end of the first capacitor is connected to the leakage detection module.

5. The leakage current detection circuit according to claim 2, characterized in that, The reference voltage generation module includes: A voltage divider unit is connected to a first power supply and is used to divide the voltage output by the first power supply to obtain a divided voltage. A voltage regulator unit is connected to the voltage divider unit and the leakage current detection module, respectively, and is used to regulate the voltage divider voltage to obtain the preset reference voltage.

6. The leakage current detection circuit according to claim 5, characterized in that, The voltage divider unit includes a first resistor, a second resistor, and a third resistor; The first end of the first resistor is connected to the first power supply. The second end of the first resistor is simultaneously connected to the first end of the second resistor, the voltage regulator unit, and the leakage current detection module. The second end of the second resistor is simultaneously connected to the first end of the third resistor and the voltage regulator unit. The second end of the third resistor is grounded.

7. The leakage current detection circuit according to claim 5, characterized in that, The voltage stabilizing unit includes a first voltage regulator; The cathode of the first voltage regulator is connected to both the voltage divider unit and the leakage current detection module, the reference terminal of the first voltage regulator is connected to the voltage divider unit, and the anode of the first voltage regulator is grounded.

8. The leakage current detection circuit according to claim 1, characterized in that, The leakage current detection module includes a first operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a second capacitor, and a third capacitor; The first end of the fourth resistor is simultaneously connected to the first end of the second capacitor, the sampling module, and the preset reference voltage. The second end of the second capacitor is grounded. The second end of the fourth resistor is connected to the non-inverting input of the first operational amplifier. The first end of the fifth resistor is connected to the sampling module. The second end of the fifth resistor is simultaneously connected to the inverting input of the first operational amplifier, the first end of the sixth resistor, and the first end of the third capacitor. The output of the first operational amplifier is simultaneously connected to the second end of the sixth resistor, the second end of the third capacitor, and the first end of the seventh resistor. The second end of the seventh resistor is used to output the leakage current detection signal.

9. The leakage current detection circuit according to claim 1, characterized in that, The leakage current detection circuit also includes: The control module is connected to the leakage current detection module and is used to receive the leakage current detection signal, and to shut down the device load and issue a leakage current warning when the leakage current detection signal is the first detection signal.

10. An air conditioner, characterized in that, The air conditioner includes a leakage current detection circuit as described in any one of claims 1 to 9.

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