CN211528651U - Electric leakage detection circuit and device - Google Patents
Electric leakage detection circuit and device Download PDFInfo
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- CN211528651U CN211528651U CN201921557365.9U CN201921557365U CN211528651U CN 211528651 U CN211528651 U CN 211528651U CN 201921557365 U CN201921557365 U CN 201921557365U CN 211528651 U CN211528651 U CN 211528651U
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Abstract
The utility model discloses a leakage detection circuit and a device, wherein the leakage detection circuit comprises a power supply circuit, a protection circuit and a leakage detection integrated chip; the power supply circuit performs half-wave rectification on the voltage of the alternating current power supply; the leakage detection integrated chip acquires waveform information after half-wave rectification, extracts alternating current synchronous information from the waveform information, and controls the power supply protection circuit to carry out self-test within a time period when the alternating current amplitude is smaller than zero according to the alternating current synchronous information so as to confirm whether the protection circuit is normal or not; the electric leakage detection integrated chip is also used for outputting an electric leakage protection signal when the alternating current amplitude value is larger than a preset threshold value. The utility model discloses carry out the self-checking to protection circuit through the negative half internal at the half-wave rectification among the technical scheme, thereby avoid arousing the spurious triggering to arouse the protection action, supply circuit can also avoid additionally setting up the power again to the power supply of earth leakage detection integrated chip simultaneously, has reduced the circuit cost.
Description
Technical Field
The utility model relates to an electric leakage detection technical field, in particular to electric leakage detection circuit and device.
Background
With the rapid popularization of household appliances, the high-frequency components in the load current of modern equipment are increased, the leakage protection standard is stricter day by day, the domestic standard is 10mA at present, and the international standard is 5mA or below. Meanwhile, the leakage detection protection circuit is required to be periodically tested to ensure normal work and avoid possible damage to human bodies due to error conditions.
In the existing self-test circuit, after the alternating current power supply is reduced, the alternating current synchronous information is provided for the self-test circuit through an additional pin. The method needs additional pins and a high-voltage isolation circuit, so the design is complex, the cost is high, and the reliability of the circuit is low.
Disclosure of Invention
The utility model aims at providing a leakage detection circuit aims at directly extracting the synchronous information of interchange from the waveform of power to improve leakage detection circuit's reliability.
In order to achieve the above object, the present invention provides an electric leakage detection circuit, which includes a power supply circuit, a protection circuit and an electric leakage detection integrated chip; the power supply circuit is connected with an alternating current power supply and is also connected with the electric leakage detection integrated chip; the protection circuit is respectively connected with the electric leakage detection integrated chip and the power supply circuit; wherein
The protection circuit is used for executing protection action when receiving the leakage protection signal;
the power supply circuit is used for carrying out half-wave rectification on the accessed alternating current power supply voltage so as to supply power to the electric leakage detection integrated chip;
the leakage detection integrated chip is used for acquiring half-wave rectified waveform information, extracting alternating current synchronous information from the waveform information, and performing self-test within a time period when the alternating current amplitude is smaller than zero according to the alternating current synchronous information so as to confirm whether the protection circuit and the current transformer are normal or not.
Preferably, the power supply circuit includes a first diode and a first resistor, an anode of the first diode is connected to the action coil, a cathode of the first diode is connected to a first end of the first resistor, and a second end of the first resistor is connected to a power supply terminal of the leakage detection integrated chip.
Preferably, the leakage detection circuit further comprises a protection circuit, and the protection circuit is respectively connected with the leakage detection integrated chip and the power supply circuit; and the protection circuit is used for executing protection action according to the leakage protection signal.
Preferably, the protection circuit includes a first switch tube, a controlled end of the first switch tube is connected to the control end of the leakage detection integrated chip, an input end of the first switch tube is connected to the power supply circuit, and an output end of the first switch tube is grounded.
Preferably, the first switch tube is a thyristor.
Preferably, the power supply circuit includes a second diode and a second resistor; the anode of the second diode is connected with the live wire of the power supply to be detected, the cathode of the second diode is connected with the first end of the second resistor, and the second end of the second resistor is connected with the second power supply of the leakage detection integrated chip.
Preferably, the leakage detection circuit further includes a working indication circuit, and the working indication circuit includes a third resistor and a first light emitting diode; the first end of the third resistor is connected with the self-checking end of the electric leakage detection integrated chip, the anode of the first light-emitting diode is connected, and the cathode of the first light-emitting diode is grounded.
Preferably, the electric leakage detection circuit further includes a first capacitor and a second capacitor, a first end of the first capacitor is connected to the control end of the electric leakage detection integrated chip, a second end of the first capacitor is connected to the ground terminal of the electric leakage detection integrated chip, the ground terminal of the electric leakage detection integrated chip is further connected to the zero line of the alternating current power supply, a first end of the second capacitor is connected to a second end of the first capacitor, and a second end of the second capacitor is further connected to the power end of the electric leakage detection integrated chip.
In order to achieve the above object, the present invention further provides an electric leakage detecting device, which includes the electric leakage detecting circuit as described above.
The utility model discloses technical scheme has formed an electric leakage detection circuit through setting up supply circuit and electric leakage detection integrated chip. The power supply circuit performs half-wave rectification on the voltage obtained by the induction of the alternating current power supply so as to supply power to the electric leakage detection integrated chip; the leakage detection integrated chip acquires waveform information after half-wave rectification, extracts alternating current synchronous information from the waveform information, and performs self-test within a time period when the alternating current amplitude is less than zero according to the alternating current synchronous information to confirm whether the protection circuit is normal or not; the electric leakage detection integrated chip is also used for outputting an electric leakage protection signal when the alternating current amplitude value is larger than a preset threshold value. The utility model discloses carry out the self-checking to protection circuit through the negative half period at the half-wave rectification among the technical scheme, thereby avoid arousing the spurious triggering to arouse the protection action, thereby supply circuit can also be to the power supply of electric leakage detection integrated chip simultaneously, and synchronous information is direct to gather from power supply loop, avoids additionally setting up the power again, has reduced the circuit cost to improve electric leakage detection circuit's reliability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a functional block diagram of an embodiment of the leakage detecting circuit of the present invention;
fig. 2 is a schematic diagram of a circuit structure of an embodiment of the leakage detecting device of the present invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) | |
| 100 | Current transformer | R1～R3 | First to |
|
| 200 | Power supply circuit | C1～C3 | First to |
|
| 300 | Electric leakage detection integrated chip | D1～D2 | First to |
|
| 400 | Protective circuit | | Current transformer | |
| 500 | Operation indicating circuit | U1 | Electric leakage detection integrated chip | |
| Q1 | Silicon controlled rectifier | D3 | First light emitting diode |
The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, it should be considered that the combination of the technical solutions does not exist, and is not within the protection scope of the present invention.
The utility model provides a leakage detection circuit.
Referring to fig. 1, in the embodiment of the present invention, the leakage detecting circuit includes a current transformer 100, a protection circuit 400, a power supply circuit 200, and a leakage detecting integrated chip 300; the leakage detection integrated chip 300 is coupled with the current transformer 100, the power supply circuit 200 is connected with an alternating current power supply, and the power supply circuit 400 is further connected with the leakage detection integrated chip 300; the protection circuit 400 is connected to the leakage detection integrated chip 300 and the power supply circuit 200, respectively; wherein
The protection circuit 400 is configured to perform a protection action when receiving the leakage protection signal. Usually, the protection circuit 400 is provided with a controllable switch tube, in this embodiment, the controllable switch tube adopts a thyristor, and the thyristor is controlled based on the leakage protection integrated chip 300 to be disconnected when performing a protection action, so as to protect the electrical equipment.
The power supply circuit 200 is configured to perform half-wave rectification on the voltage induced by the ac power supply;
the leakage detection integrated chip 300 is configured to obtain waveform information after half-wave rectification, extract alternating current synchronization information from the waveform information, and perform self-test within a time period in which an alternating current amplitude is smaller than a preset threshold value according to the alternating current synchronization information to determine whether the protection circuit 400 is normal; the electric leakage detection integrated chip is also used for outputting an electric leakage protection signal when the alternating current amplitude value is larger than a preset threshold value.
It should be noted that in this embodiment, when performing self-test on the current transformer 100, an excitation power supply may be set as needed, and may be one of a direct current excitation power supply, a low frequency excitation power supply, and a high frequency excitation power supply, or a combination of multiple types. For example, when the preset excitation power supply includes a low-frequency excitation power supply and a high-frequency excitation power supply, the low-frequency excitation power supply and the high-frequency excitation power supply are turned on and operated for 600 milliseconds at the same time, and then turned off for 600 milliseconds, as one working cycle. When the silicon controlled rectifier in the protection circuit is subjected to self test, whether the silicon controlled rectifier works normally can be determined by controlling the on-off of the silicon controlled rectifier and detecting the related voltage of the silicon controlled rectifier.
The current transformer 100 is configured to couple a preset excitation power source to the ac power source. The turns ratio of the current transformer 100 in this embodiment is 1: 1000. The zero line and the live line of the alternating current power supply pass through the magnetic ring of the current transformer 100.
The power supply circuit 200 is configured to rectify the voltage induced by the ac power supply, and simultaneously obtain half-wave rectified waveform information from the leakage detection integrated chip. In this embodiment, when the leakage protection circuit operates, the voltage induced by the ac power supply is rectified to obtain a target monitoring voltage, and the reference voltage is subtracted from the target monitoring voltage to obtain a difference between the target monitoring voltage and the reference voltage.
The protection circuit 400 is provided with leakage protection components such as a thyristor and a release, and since faults such as open circuit and short circuit may occur in the current transformer 100 and the thyristor Q1 during operation, self-testing of these components is required. The embodiment can perform self-test, namely synchronous test, while performing leakage protection. In this embodiment, the synchronous test may be performed in a time period when the ac amplitude is less than zero. It can be understood that, in this embodiment, a period of time may be selected to perform the synchronization test in a time period when the ac amplitude is less than zero, and the setting may be specifically performed according to an actual requirement, which is not limited herein.
It should be noted that the leakage detecting integrated chip 300 is provided with a voltage stabilizing and power supplying module for supplying power to other modules of the chip. The leakage detection integrated chip 300 is further provided with a synchronous test module, a silicon controlled test control module, a test excitation module, a signal amplification and conditioning module, a leakage module function module and a mutual inductor test module. The synchronous test module is used for completing synchronous test.
The leakage detection integrated chip 300 may be integrated with a digital filter, an operational amplifier, an and gate, an or gate, a nor gate and other logic devices (gate circuits), a timing controller, a timer, a D trigger and other hardware circuits, and may also be integrated with a software algorithm to determine whether the electrical equipment leaks electricity according to the power signal detected by the current transformer 100, and the leakage detection integrated chip 300 is also integrated with a self-test software program and a hardware circuit for performing self-test on the thyristor, the current transformer 100 and other components in the leakage protection circuit, so as to implement self-test on the leakage protection circuit while the electrical equipment performs leakage protection, thereby ensuring the safety of the thyristor, the current transformer 100 and other important components in the leakage protection, and improving the reliability of the leakage protection.
It should be noted that, the leakage detection integrated chip 300 tests the protection circuit of the leakage detection integrated circuit (including the chip and the external device) by detecting the ac synchronization information existing in the power supply signal when appropriate (within a certain time period when the ac amplitude is smaller than zero), so as to prevent the test of the thyristor when the ac amplitude is high from causing an erroneous protection action, thereby preventing the trigger of the action protection mechanism during the test. The utility model discloses technical scheme supplies power for electric leakage detection integrated chip 300 through setting up power supply circuit 200, and electric leakage detection integrated chip 300 is according to the output to the power signal of load that current sensor 100 etc. gathered, electric leakage detection integrated chip 300 still is used for exporting the earth leakage protection signal when the alternating current amplitude of the power signal who detects is greater than and predetermines the threshold value. And determining whether the electrical equipment suitable for the leakage protection circuit leaks electricity, and controlling the protection circuit 400 to perform leakage protection when the electrical equipment leaks electricity. The utility model discloses power supply circuit 200 carries out half-wave rectification to alternating current power supply 200 voltage and provides power supply for electric leakage detection integrated chip; the leakage detection integrated chip 300 may obtain waveform information after half-wave rectification from the power supply output by the power supply circuit 200, extract ac synchronization information from the waveform information, and perform self-test of the components such as the thyristor and the current transformer 100 in the protection circuit 400 within a time period in which the ac amplitude is less than zero according to the ac synchronization information to determine whether the protection circuit 400 and the current transformer 100 are normal, thereby improving the reliability of leakage protection of the electrical equipment itself; the utility model discloses can select among the technical scheme carry out self-checking to protection circuit in the negative half-cycle of half-wave rectification to thereby avoid arousing the spurious triggering to arouse the protection action. In this embodiment, the power supply circuit 200 is a power supply source for the leakage detecting integrated chip 300, and the synchronization signal is directly collected from the power supply circuit 200, so that it is avoided that an additional path of alternating current signal is specially used for providing synchronization information, and therefore, an additional path of synchronous alternating current signal is prevented from being additionally introduced, an additional high-voltage isolation circuit is required, and the additional rectification and the circuit design have large cost in terms of cost and complexity. In other words, the power supply circuit 200 supplies power to the leakage detection integrated chip 300, and the leakage detection integrated chip 300 can sample waveform information in the power supply circuit, so as to obtain a synchronization signal, avoid additional arrangement of a sampling circuit, and reduce the cost of the leakage protection device.
The waveform information may be a voltage amplitude, or a phase of the power supply signal, etc. may be used to embody the waveform information of the power supply signal. The present embodiment may be selected to obtain the phase of the alternating voltage VAC with respect to the power supply signal by monitoring the voltage of the power supply signal, thereby obtaining an appropriate test time. When the voltage of the power supply signal is reduced from high to low and is within a certain range, the test time period can be determined, or the change of the power supply signal is detected, when the slope of the change is positive/negative, the alternating current phase is deduced, or the collected alternating current phase is converted into a digital signal through an analog-digital converter, and then the digital signal is processed and judged according to the collected digital signal.
Referring to fig. 2, in the embodiment, the power supply circuit 200 includes a first diode D1 and a first resistor R1, an anode of the first diode D1 is connected to the zero line of the ac power source, a cathode of the first diode D1 is connected to a first end of the first resistor R1, and a second end of the first resistor R1 is connected to the power source terminal VDD of the integrated leakage detecting chip U1.
The first diode D1 is used to rectify ac power in the ac power supply into dc power. The first resistor is used for limiting current and preventing a large current in the alternating current power supply from burning out a chip.
Further, the leakage detection circuit further includes a protection circuit 400, and the protection circuit 400 is connected to the leakage detection integrated chip 300 and the power supply circuit 200 respectively; the protection circuit 400 is configured to perform a protection action according to the leakage protection signal.
In this embodiment, the protection circuit includes a first switch tube, a controlled end of the first switch tube is connected to the control end of the leakage detection integrated chip 300, an input end of the first switch tube is connected to the power supply circuit 200, and an output end of the first switch tube is grounded. The first switch tube is a thyristor Q1, but other controllable switches, such as a relay, etc., may be used.
When the control terminal Scr of the leakage detection integrated chip 300 outputs a leakage protection signal, the thyristor Q1 is turned on, and the live wire of the ac power supply is connected to the ground, so as to prevent the influence of the leakage of the ac power supply on personal safety.
Specifically, the power supply circuit 200 includes a second diode D2 and a second resistor R2; the anode of the second diode D2 is connected to the live wire of the power source to be tested, the cathode of the second diode D2 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the second power source VDD2 of the integrated leakage detecting chip 300. The second diode D2 is used to rectify ac power from the ac power source into dc power. The second resistor R2 is used for limiting current and preventing the chip from being burned out by large current in the alternating current power supply.
Further, the leakage detection circuit further comprises an operation indication circuit 500, wherein the operation indication circuit 500 comprises a third resistor R3 and a first light emitting diode D3; the first end of the third resistor R3 is connected with the self-checking end of the leakage detection integrated chip U1, the anode of the first light-emitting diode D3 is connected, and the cathode of the first light-emitting diode D3 is grounded.
It should be noted that the integrated chip 300 has a self-checking function, and when the self-checking is normal, the working indication circuit emits green light; when the self-checking fails, a red warning light is emitted.
Further, the leakage detection circuit further includes a first capacitor C1 and a second capacitor C2, a first end of the first capacitor C1 is connected to the control terminal Scr of the leakage detection integrated chip U1, a second end of the first capacitor C1 is connected to a ground terminal GND of the leakage detection integrated chip U1, a ground terminal GND of the leakage detection integrated chip U1 is further connected to a power supply zero line of an ac power supply, a first end of the second capacitor C2 is connected to a second end of the first capacitor C1, and a second end of the second capacitor C2 is further connected to a power terminal VDD of the leakage detection integrated chip U1.
The first capacitor C1 and the second capacitor C2 are both used for filtering and stabilizing voltage, so that the voltage input to the port of the leakage detection integrated chip U1 is more stable and accurate.
In this embodiment, the leakage detecting integrated chip 300 further includes an excitation terminal CT and a ground terminal GND, wherein the excitation terminal CT is connected to one end of the current transformer 100, and the second end of the current transformer 100 is connected to the ground terminal GND of the leakage detecting integrated chip U1.
In order to achieve the above object, the present invention further provides an electric leakage detecting device, which includes the electric leakage detecting circuit as described above.
The utility model also provides an earth leakage protection device, this earth leakage protection device include as above earth leakage protection circuit, this earth leakage protection circuit's concrete structure refers to above-mentioned embodiment, because this earth leakage protection device has adopted the whole technical scheme of above-mentioned all embodiments, consequently has all beneficial effects that the technical scheme of above-mentioned embodiment brought at least, no longer gives unnecessary details one by one here.
The earth leakage protection device may be an earth leakage protection instrument.
The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structure changes made by the contents of the specification and the drawings under the inventive concept of the present invention, or the direct/indirect application in other related technical fields are included in the patent protection scope of the present invention.
Claims (8)
1. The electric leakage detection circuit is characterized by comprising a power supply circuit, a protection circuit and an electric leakage detection integrated chip; the power supply circuit is connected with an alternating current power supply and is also connected with the electric leakage detection integrated chip; the protection circuit is respectively connected with the electric leakage detection integrated chip and the power supply circuit; wherein
The protection circuit is used for executing protection action when receiving the leakage protection signal;
the power supply circuit is used for carrying out half-wave rectification on the accessed alternating current power supply voltage so as to supply power to the electric leakage detection integrated chip;
the leakage detection integrated chip is used for acquiring half-wave rectified waveform information, extracting alternating current synchronous information from the waveform information, and performing self-test within a time period when the alternating current amplitude is smaller than zero according to the alternating current synchronous information so as to confirm whether the protection circuit and the current transformer are normal or not.
2. The electrical leakage detection circuit of claim 1, wherein the power supply circuit comprises a first diode and a first resistor, an anode of the first diode is connected to the operating coil, a cathode of the first diode is connected to a first terminal of the first resistor, and a second terminal of the first resistor is connected to a power supply terminal of the electrical leakage detection integrated chip.
3. The leakage detection circuit of claim 1, wherein the protection circuit comprises a first switch tube, a controlled terminal of the first switch tube is connected to the control terminal of the leakage detection ic, an input terminal of the first switch tube is connected to the power supply circuit, and an output terminal of the first switch tube is grounded.
4. The electrical leakage detection circuit of claim 3, wherein the first switching tube is a thyristor.
5. The electrical leakage detection circuit of claim 1, wherein the power supply circuit comprises a second diode and a second resistor; the anode of the second diode is connected with a live wire of a power supply to be detected, the cathode of the second diode is connected with the first end of the second resistor, and the second end of the second resistor is connected with the second power supply of the leakage detection integrated chip.
6. The leakage detection circuit of claim 1, further comprising an operation indication circuit, the operation indication circuit comprising a third resistor and a first light emitting diode; the first end of the third resistor is connected with the self-checking end of the electric leakage detection integrated chip, the anode of the first light-emitting diode is connected, and the cathode of the first light-emitting diode is grounded.
7. The electrical leakage detection circuit according to claim 1, wherein the electrical leakage detection circuit further comprises a first capacitor and a second capacitor, a first end of the first capacitor is connected to the control terminal of the electrical leakage detection integrated chip, a second end of the first capacitor is connected to a ground terminal of the electrical leakage detection integrated chip, the ground terminal of the electrical leakage detection integrated chip is further connected to a zero line of an alternating current power source, a first end of the second capacitor is connected to a second end of the first capacitor, and a second end of the second capacitor is further connected to a power terminal of the electrical leakage detection integrated chip.
8. An electrical leakage detection device, characterized in that the electrical leakage detection device comprises an electrical leakage detection circuit according to any one of claims 1 to 7.
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| CN201921557365.9U CN211528651U (en) | 2019-09-17 | 2019-09-17 | Electric leakage detection circuit and device |
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| CN201921557365.9U CN211528651U (en) | 2019-09-17 | 2019-09-17 | Electric leakage detection circuit and device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110596514A (en) * | 2019-09-17 | 2019-12-20 | 深圳市晶扬电子有限公司 | Leakage detection circuit, device and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110596514A (en) * | 2019-09-17 | 2019-12-20 | 深圳市晶扬电子有限公司 | Leakage detection circuit, device and method |
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