CN110297156B - Circuit and method for detecting electric leakage through electric leakage voltage - Google Patents
Circuit and method for detecting electric leakage through electric leakage voltage Download PDFInfo
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- CN110297156B CN110297156B CN201910752383.0A CN201910752383A CN110297156B CN 110297156 B CN110297156 B CN 110297156B CN 201910752383 A CN201910752383 A CN 201910752383A CN 110297156 B CN110297156 B CN 110297156B
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The embodiment of the invention discloses a circuit and a method for detecting electric leakage through electric leakage voltage, wherein the detection circuit comprises an optical coupling isolation circuit, a pulse filtering circuit, an analog amplifying circuit and a trigger release-suppressing circuit, wherein the optical coupling isolation circuit is used for converting the electric leakage voltage into an electric leakage pulse signal, the pulse filtering circuit is used for filtering the electric leakage pulse signal, the analog amplifying circuit is used for carrying out amplitude conditioning on the filtered signal, and the trigger release-suppressing circuit is used for converting the signal after amplitude conditioning into a LEVEL signal level_output and latching or releasing the LEVEL signal level_output. The invention detects the electric leakage through the electric leakage voltage driving detection circuit and outputs the electric leakage display signal, solves the problem that the electric leakage cannot be detected due to poor grounding, has wide application range, and can be used for detecting the electric leakage by all equipment with metal shells.
Description
Technical Field
The invention relates to the technical field of electricity safety detection, in particular to a circuit and a method for detecting electric leakage through electric leakage voltage.
Background
Along with the development of national economy, more and more electric equipment, such as street lamps, transformer boxes, power distribution cabinets and other equipment facilities, are used. If the metal shell of these devices is poorly grounded, safety accidents can be caused when the devices leak electricity.
Safety voltage refers to voltage that does not cause direct death or disablement of a person, and the "safe extra low voltage" that allows sustained contact under normal ambient conditions is 36V. Industry prescribes that the safety voltage is not higher than 36V, the continuous contact safety voltage is 24V, the safety current is 10mA, and the harm degree of electric shock to human body mainly depends on the magnitude of current passing through the human body and the electrifying time. The greater the current intensity, the greater the fatal risk; the longer the duration, the greater the likelihood of death. The minimum current value which can cause human perception is called perceived current, the alternating current is 1mA, and the direct current is 5mA; the maximum current which can be escaped by the person after the person gets an electric shock is called escaped current, the alternating current is 10mA, and the direct current is 50mA; the life-threatening current in a short time is called a fatal current, for example, a current of 100mA passes through the human body for 1s, which is enough to make the human body fatal, and thus the fatal current is 50mA. In the case of an electric shock protection device, the current allowed by the human body can be generally considered as 30 mA. Because of the specificity of many electric occasions, the action current of the line leakage protector is designed to be 300mA (because the design is small, and the line leakage protector cannot be switched on in practical application), and thus potential safety hazards exist, such as a street lamp system.
The traditional leakage detection method generally detects leakage current, if the metal shell is in leakage current and is in poor grounding, the leakage current cannot be discharged, so that leakage current cannot be generated, and the leakage problem is difficult to find by the technical means before no safety accident occurs.
Disclosure of Invention
The embodiment of the invention provides a circuit and a method for detecting electric leakage through electric leakage voltage, which are used for solving the problem that electric leakage cannot be detected due to poor grounding in the prior art. The invention determines that the leakage occurs through the leakage voltage, is not limited to be applied to a certain occasion, and can be used for detecting the leakage by all equipment with a metal shell.
The embodiment of the invention discloses the following technical scheme:
the invention provides a circuit for detecting electric leakage through electric leakage voltage, which comprises an optocoupler isolation circuit, a PULSE filter circuit, an analog amplifying circuit and a trigger release circuit which are sequentially connected, wherein the optocoupler isolation circuit is used for converting electric leakage voltage into electric leakage PULSE signals PULSEs, the PULSE filter circuit is used for filtering the electric leakage PULSE signals PULSEs, the analog amplifying circuit is used for carrying out amplitude conditioning on filtered signals, and the trigger release circuit is used for converting the amplitude conditioned signals into LEVEL signals LEVEL_OUTPUT and carrying out latching or releasing on the LEVEL_OUTPUT.
Further, the optocoupler isolation circuit comprises a half-wave rectification circuit and a level conversion circuit, the half-wave rectification circuit carries out half-wave rectification on the leakage voltage, and the level conversion circuit converts output of the half-wave rectification circuit into a leakage PULSE signal PULSE.
Further, the half-wave rectification circuit comprises a diode D1, an optical coupler U1 input end and a resistor R1, wherein the anode of the diode D1 is connected with the anode of the leakage voltage, the cathode of the diode D1 is connected with the anode of the input end of the optical coupler U1, the cathode of the input end of the optical coupler U1 is connected with the cathode of the leakage voltage through the resistor R1, the level conversion circuit comprises an optical coupler U1 output end and a resistor R2, the anode of the output end of the optical coupler U1 is connected with a power VCC, the cathode of the output end of the optical coupler U1 is connected with one end of a resistor R8 and one end of a resistor R2, and the other end of the resistor R2 is grounded;
in the positive half cycle of alternating current, a leakage voltage positive electrode forms a unidirectional loop through a diode D1, an input end of an optocoupler U1, a resistor R1 and a leakage voltage negative electrode, the optocoupler U1 is driven to output a leakage PULSE signal PULSE, and in the negative half cycle of alternating current, the diode D1 is reversely cut off, and the unidirectional loop is not conducted.
Further, the pulse filtering circuit comprises a resistor R8 and a capacitor C20, the other end of the resistor R8 is connected with one end of the capacitor C20 and one end of the resistor R9, and the other end of the capacitor C20 is grounded.
Further, the analog amplifying circuit comprises an operational amplifier U2A, the other end of a resistor R9 is connected with a positive input end of the operational amplifier U2A, an output end of the operational amplifier U2A is connected with one end of a resistor R7 and one end of a capacitor C19 and is connected with a negative input end of the operational amplifier U2A through a resistor R3, the other end of the capacitor C19 is grounded, the other end of the resistor R7 is grounded through a resistor R10, the output end of the operational amplifier U2A forms a voltage dividing circuit through the resistor R7 and the resistor R10, and the negative input end of the operational amplifier U2A is grounded through a resistor R6; the operational amplifier U2A amplifies the leakage PULSE signal PULSE, isolates the leakage PULSE signal PULSE from a later-stage circuit, and the capacitor C19 performs smooth filtering on the output signal of the operational amplifier U2A.
Further, the trigger release circuit comprises a trigger unit and a release unit, wherein the trigger unit is responsible for converting a pulse signal generated by the voltage dividing circuit into a LEVEL signal level_output, the level_output is fed back to the input end of the trigger unit, and when the voltage division is greater than a threshold voltage, the level_output is a high LEVEL signal; the release unit controls the OUTPUT voltage LEVEL_OUTPUT of the trigger unit through a control signal Unlock, when the control signal Unlock is at a low LEVEL, the release unit latches a LEVEL_OUTPUT high LEVEL signal, and when the control signal Unlock is at a high LEVEL, the release unit releases the LEVEL_OUTPUT signal.
Further, the triggering unit comprises an operational amplifier U2B, the voltage division is connected with the positive input end of the operational amplifier U2B, a power supply VCC forms a threshold voltage circuit through resistors R4 and R5, the threshold voltage is connected with the negative input end of the operational amplifier U2B, the output end of the operational amplifier U2B is connected with the positive electrode of a diode D2 and one end of a resistor R14, the releasing unit comprises an NPN triode Q1, the E electrode of the Q1 is grounded, the B electrode of the Q1 is connected with a singlechip control signal Unlock through a resistor R12, the C electrode of the Q1 is connected with the positive input end of the operational amplifier U2B, and the negative electrode of the diode D2 is connected with the positive input end of the operational amplifier U2B through a resistor R11;
when the control signal Unlock is low LEVEL and the voltage division is larger than the threshold voltage, the OUTPUT voltage LEVEL_OUTPUT of the operational amplifier U2B is high LEVEL, the NPN triode Q1 is not conducted, the LEVEL_OUTPUT is fed back to the positive input end of the U2B through the diode D2 and the resistor R11, the high LEVEL signal latch of the LEVEL_OUTPUT is realized,
when the control signal Unlock is at a high LEVEL, the NPN triode Q1 is conducted, the forward input end of the U2B is 0V, the input of the operational amplifier U2B is restrained, the U2B operational amplifier OUTPUTs a low-LEVEL signal, and the release of the LEVEL_OUTPUT signal is realized.
Further, the circuit comprises a display circuit, the display circuit comprises an NPN triode Q2, a light emitting diode D3, a resistor R13 and a resistor R14, the other end of the resistor R14 is connected with the B pole of the Q2, the E pole of the Q2 is grounded, the C pole of the Q2 is connected with one end of the resistor R13, VCC is connected with the positive pole of the light emitting diode D3, and the negative pole of the light emitting diode D3 is connected with the other end of the resistor R13; when the OUTPUT voltage level_output is high, the NPN transistor Q2 is turned on, and the diode D3 is turned on, indicating that the leakage voltage is detected.
A second aspect of the present invention provides a method of detecting leakage by a leakage voltage, the method comprising:
s1, the leakage voltage is converted into a leakage PULSE signal PULSE through the optocoupler isolation circuit;
s2, the PULSE filtering circuit filters leakage PULSE signals, when the width of the leakage PULSE signals is smaller than the preset time, the PULSE is filtered, and only high-level PULSE which is larger than the preset time can smoothly pass through the PULSE filtering circuit;
s3, the analog amplifying circuit carries out amplitude conditioning on the filtered pulse signals;
and S4, the trigger release circuit is used for converting the pulse signal subjected to amplitude conditioning into a LEVEL signal level_output and latching or releasing the LEVEL signal level_output.
Further, the method for triggering the latch or release of the release circuit comprises the following steps:
when the control signal Unlock is low LEVEL and the voltage division is larger than the threshold voltage, the OUTPUT voltage LEVEL_OUTPUT of the trigger unit is high LEVEL, so that the LEVEL_OUTPUT high LEVEL signal is latched;
when the Unlock signal is at high LEVEL, the input end of the trigger unit is 0V, and the OUTPUT voltage level_output is at low LEVEL, so as to release the level_output signal.
The effects provided in the summary of the invention are merely effects of embodiments, not all effects of the invention, and one of the above technical solutions has the following advantages or beneficial effects:
according to the circuit and the method for detecting electric leakage through the electric leakage voltage, the electric leakage voltage between the metal shell and the zero line is detected, when the electric leakage voltage of the metal shell exceeds the safety voltage and is in poor grounding, the electric leakage voltage drives the optocoupler, so that the optocoupler generates an electric leakage pulse signal, the electric leakage pulse signal is filtered by the pulse filtering circuit and amplified by the analog amplifying circuit, the signal is captured through the triggering releasing circuit and converted into a level signal to be latched, the level signal is displayed and reminded through the light emitting diode, and the latched signal is released after the electric leakage problem is relieved. The invention detects the electric leakage through the electric leakage voltage driving detection circuit and outputs the electric leakage display signal, solves the problem that the electric leakage cannot be detected due to poor grounding, has wide application range, and can be used for detecting the electric leakage by all equipment with metal shells.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
FIG. 1 is a block diagram of a circuit configuration according to the present invention;
FIG. 2 is a schematic circuit diagram of an embodiment of the present invention;
in the figure, a 1-optocoupler isolation circuit, a 2-pulse filter circuit, a 3-analog amplifying circuit and a 4-trigger release circuit are shown.
Detailed Description
In order to clearly illustrate the technical features of the present solution, the present invention will be described in detail below with reference to the following detailed description and the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different structures of the invention. In order to simplify the present disclosure, components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and processes are omitted so as to not unnecessarily obscure the present invention.
As shown in fig. 1 and 2, the embodiment of the invention provides a circuit for detecting electric leakage through electric leakage voltage, which comprises an optocoupler isolation circuit 1, a pulse filter circuit 2, an analog amplifying circuit 3 and a trigger release circuit 4 which are connected in sequence; the optocoupler isolation circuit 1 is used for converting leakage voltage into leakage PULSE signals, the PULSE filtering circuit 2 is used for filtering the leakage PULSE signals, the analog amplifying circuit 3 is used for carrying out amplitude conditioning on the filtered PULSE signals, the trigger release circuit 4 is used for converting the PULSE signals subjected to amplitude conditioning into LEVEL signals level_output and latching or releasing the LEVEL signals level_output.
The optical coupling isolation circuit comprises a half-wave rectification circuit and a level conversion circuit, the half-wave rectification circuit carries out half-wave rectification on the leakage voltage, and the level conversion circuit converts the output of the half-wave rectification circuit into a leakage PULSE signal PULSE.
The half-wave rectification circuit comprises a diode D1, an input end of an optocoupler U1 and a resistor R1, wherein the positive electrode of the diode D1 is connected with the positive electrode of the leakage voltage, the negative electrode of the diode D1 is connected with the positive electrode of the input end of the optocoupler U1, and the negative electrode of the input end of the optocoupler U1 is connected with the negative electrode of the leakage voltage through the resistor R1.
The level conversion circuit comprises an output end of the optical coupler U1 and a resistor R2, wherein the positive electrode of the output end of the optical coupler U1 is connected with a power supply VCC, the negative electrode of the output end of the optical coupler U1 is connected with one end of a resistor R8 and one end of the resistor R2, and the other end of the resistor R2 is grounded.
Referring to fig. 2, the position denoted by PE is connected to the metal casing of the device, and the position denoted by N is connected to the zero line, so that the leakage voltage is mostly ac, and therefore half-wave rectification is performed through the diode D1; if the metal shell is in contact with the live wire, namely the metal shell has leakage voltage, when the voltage reaches or exceeds the safety voltage (36V), the current can drive the optocoupler. In the positive half cycle of alternating current, the metal shell forms a unidirectional loop through the diode D1, the optocoupler U1, the resistor R1 and the zero line, so that the optocoupler U1 is driven, the electric leakage PULSE signal PULSE is output by the optocoupler U1, and in the negative half cycle of alternating current, the unidirectional loop is not conducted due to the reverse cut-off characteristic of the diode D1, so that the reverse input of the optocoupler is prevented.
The pulse filter circuit 2 comprises a resistor R8 and a capacitor C20, wherein the other end of the resistor R8 is connected with the capacitor C20 and the resistor R9, and the other end of the capacitor C20 is grounded; in this embodiment, R8 and C20 form a low-pass filter, and since the leakage voltage is not constant in duration, the filter is used for sensitivity setting, when the width of the leakage PULSE signal PULSE is smaller than a predetermined time, the PULSE can be greatly attenuated to be close to 0V by the filter circuit, the PULSE is filtered out and cannot pass through the filter, so that the subsequent circuit cannot be reached, and only the high-level PULSE larger than the predetermined time can smoothly pass through the PULSE filter circuit.
The analog amplifying circuit 3 comprises an operational amplifier U2A, the other end of a resistor R9 is connected with the positive input end of the operational amplifier U2A, the output end of the operational amplifier U2A is connected with one end of a resistor R7 and one end of a capacitor C19, the analog amplifying circuit is connected with the negative input end of the operational amplifier U2A through a resistor R3, the other end of the capacitor C19 is grounded, the other end of the resistor R7 is grounded through a resistor R10, the output end of the operational amplifier U2A forms a voltage division circuit through the resistor R7 and the resistor R10, and the negative input end of the operational amplifier U2A is grounded through a resistor R6.
In this embodiment, the analog amplifying circuit 3 is an in-phase proportional amplifying circuit formed by the operational amplifier U2A, the resistors R3, R6 and R9, and because the magnitudes of the leakage pulse signals output by the optical coupler U1 are different due to the driving of different leakage voltages, the analog amplifying circuit 3 mainly conditions the magnitudes of the pulse signals, amplifies the pulse signals with different magnitudes to a required voltage threshold value, meanwhile, the circuit realizes the isolation of the front and rear stage circuits, the capacitor C19 performs smooth filtering on the output signal of the operational amplifier U2A, and the electric groups R7 and R10 divide the voltage of the output signal of the operational amplifier U2A, so that the isolation of the output voltage of the rear stage operational amplifier U2B is mainly realized.
The trigger release circuit 4 comprises a trigger unit and a release unit, the trigger unit is responsible for converting a pulse signal generated by the voltage dividing circuit into a LEVEL signal level_output, the level_output is fed back to the input end of the trigger unit, and when the voltage division is greater than a threshold voltage, the level_output is a high LEVEL signal; the release unit controls the OUTPUT voltage LEVEL_OUTPUT of the trigger unit through the control signal Unlock, when the control signal Unlock is at a low LEVEL, the release unit latches the LEVEL_OUTPUT high LEVEL signal, and when the control signal Unlock is at a high LEVEL, the release unit releases the LEVEL_OUTPUT signal, so that the OUTPUT end of the trigger unit is recovered to a low LEVEL.
The trigger unit comprises an operational amplifier U2B, the voltage division is connected with the positive input end of the operational amplifier U2B, the power supply VCC forms a threshold voltage circuit through resistors R4 and R5, the threshold voltage is connected with the negative input end of the operational amplifier U2B, and the output end of the operational amplifier U2B is connected with the positive electrode of a diode D2 and one end of a resistor R14.
The releasing and suppressing unit comprises NPN triodes Q1 and Q1, wherein the E pole of the NPN triodes Q1 is grounded, the B pole of the Q1 is connected with a control signal Unlock of a singlechip (the model of the singlechip is STM8L151C8T 6) through a resistor R12, the C pole of the Q1 is connected with the positive input end of an operational amplifier U2B, and the negative pole of a diode D2 is connected with the positive input end of the operational amplifier U2B through a resistor R11.
Since short-time leakage occurs at any time, pulse signals also occur at any time, and if the signals are not captured in time, they are slightly elapsed, and thus the detection is missed, so that in order to better detect the occurrence of leakage, the pulse signals need to be converted into LEVEL signals level_output.
When the circuit works, a control signal Unlock is set to be low LEVEL, an NPN triode Q1 is not conducted, if LEVEL_OUTPUT is OUTPUT to be high LEVEL, the occurrence of electric leakage is indicated, a singlechip can judge whether electric leakage occurs or not by detecting LEVEL_OUTPUT LEVEL signals, R4 and R5 divide VCC and are used for setting threshold voltage, the VCC is provided for a negative input end of an operational amplifier U2B to serve as a reference, if the partial voltage of a positive input end of the U2B exceeds the threshold voltage, the OUTPUT voltage LEVEL_OUTPUT of the operational amplifier U2B is high LEVEL, meanwhile, an OUTPUT signal is fed back to the positive input end of the operational amplifier U2B through a diode D2 and a resistor R11, the pulse signal OUTPUT by a front-stage circuit can be monitored in real time, the LEVEL_OUTPUT high LEVEL signal is latched, and the electric leakage voltage is detected at the moment;
if the control signal Unlock is set to high LEVEL, the NPN triode Q1 is turned on, the forward input end of the U2B is 0V, the input of the operational amplifier U2B is restrained, the OUTPUT voltage LEVEL_OUTPUT of the U2B is a low LEVEL signal, and if the operational amplifier latches to be high LEVEL signal at this time, the high LEVEL signal is also released, so that the release of the LEVEL_OUTPUT signal is realized.
The circuit comprises a display circuit, wherein the display circuit comprises an NPN triode Q2, a light emitting diode D3, a resistor R13 and a resistor R14, the other end of the resistor R14 is connected with the B pole of the Q2, the E pole of the Q2 is grounded, the C pole of the Q2 is connected with one end of the resistor R13, VCC is connected with the positive pole of the light emitting diode D3, and the negative pole of the light emitting diode D3 is connected with the other end of the resistor R13; when the OUTPUT voltage level_output is high, the NPN transistor Q2 is turned on, and the diode D3 is turned on, indicating that the leakage voltage is detected.
The method for detecting electric leakage through the electric leakage voltage provided by the invention comprises the following steps:
s1, the leakage voltage is converted into a leakage PULSE signal PULSE through an optocoupler isolation circuit 1;
s2, the PULSE filtering circuit 2 filters leakage PULSE signals, when the width of the leakage PULSE signals is smaller than the preset time, the PULSE is filtered, and only high-level PULSE which is larger than the preset time can smoothly pass through the PULSE filtering circuit 2;
s3, the analog amplifying circuit 3 carries out amplitude conditioning on the filtered pulse signals;
and S4, the trigger release circuit 4 is used for converting the pulse signal subjected to amplitude conditioning into a LEVEL signal level_output and latching or releasing the LEVEL signal level_output.
The method for triggering the latch or release of the release circuit comprises the following steps:
when the control signal Unlock is low LEVEL and the voltage division is larger than the threshold voltage, the OUTPUT voltage LEVEL_OUTPUT of the trigger unit is high LEVEL, so that the LEVEL_OUTPUT high LEVEL signal is latched;
when the Unlock signal is at high LEVEL, the input end of the trigger unit is at 0V, and the OUTPUT voltage level_output is at low LEVEL, so that the release of the level_output signal is realized.
The foregoing is only a preferred embodiment of the present invention, and it will be apparent to those skilled in the art that numerous modifications and variations can be made without departing from the principles of the invention, and such modifications and variations are considered to be within the scope of the invention.
Claims (8)
1. The circuit for detecting the electric leakage through the electric leakage voltage is characterized by comprising an optocoupler isolation circuit, a PULSE filtering circuit, an analog amplifying circuit and a trigger release circuit which are sequentially connected, wherein the optocoupler isolation circuit is used for converting the electric leakage voltage into electric leakage PULSE signals PULSEs, the PULSE filtering circuit is used for filtering the electric leakage PULSE signals PULSEs, the analog amplifying circuit is used for carrying out amplitude conditioning on the filtered signals, and the trigger release circuit is used for converting the signals subjected to amplitude conditioning into LEVEL signals LEVEL_OUTPUT and carrying out latching or release on the LEVEL_OUTPUT;
the trigger release circuit comprises a trigger unit and a release unit, the trigger unit is responsible for converting a pulse signal generated by the voltage dividing circuit into a LEVEL signal level_output, the level_output is fed back to the input end of the trigger unit, and when the voltage division is greater than a threshold voltage, the level_output is a high LEVEL signal; the release unit controls the OUTPUT voltage LEVEL_OUTPUT of the trigger unit through a control signal Unlock, when the control signal Unlock is at a low LEVEL, the release unit latches a LEVEL_OUTPUT high LEVEL signal, and when the control signal Unlock is at a high LEVEL, the release unit releases the LEVEL_OUTPUT signal;
the trigger unit comprises an operational amplifier U2B, the voltage division is connected with the positive input end of the operational amplifier U2B, a power supply VCC forms a threshold voltage circuit through resistors R4 and R5, the threshold voltage is connected with the negative input end of the operational amplifier U2B, the output end of the operational amplifier U2B is connected with the positive electrode of a diode D2 and one end of a resistor R14, the release unit comprises an NPN triode Q1, the E electrode of the Q1 is grounded, the B electrode of the Q1 is connected with a singlechip control signal Unlock through a resistor R12, the C electrode of the Q1 is connected with the positive input end of the operational amplifier U2B, and the negative electrode of the diode D2 is connected with the positive input end of the operational amplifier U2B through a resistor R11;
when the control signal Unlock is low LEVEL and the voltage division is larger than the threshold voltage, the OUTPUT voltage LEVEL_OUTPUT of the operational amplifier U2B is high LEVEL, the NPN triode Q1 is not conducted, the LEVEL_OUTPUT is fed back to the positive input end of the U2B through the diode D2 and the resistor R11, the high LEVEL signal latch of the LEVEL_OUTPUT is achieved, when the control signal Unlock is high LEVEL, the NPN triode Q1 is conducted, the positive input end of the U2B is 0V, the input of the operational amplifier U2B is restrained, the U2B operational amplifier OUTPUTs a low LEVEL signal, and the release of the LEVEL_OUTPUT signal is achieved.
2. The circuit for detecting leakage through a leakage voltage according to claim 1, wherein the optocoupler isolation circuit comprises a half-wave rectification circuit that half-wave rectifies the leakage voltage and a level conversion circuit that converts an output of the half-wave rectification circuit into a leakage PULSE signal PULSE.
3. The circuit for detecting leakage through the leakage voltage according to claim 2, wherein the half-wave rectification circuit comprises a diode D1, an input end of an optocoupler U1 and a resistor R1, wherein an anode of the diode D1 is connected with an anode of the leakage voltage, a cathode of the diode D1 is connected with an anode of the input end of the optocoupler U1, an anode of the input end of the optocoupler U1 is connected with an anode of the leakage voltage through the resistor R1, the level conversion circuit comprises an output end of the optocoupler U1 and the resistor R2, the anode of the output end of the optocoupler U1 is connected with a power VCC, an anode of the output end of the optocoupler U1 is connected with one end of the resistor R8 and one end of the resistor R2, and the other end of the resistor R2 is grounded;
in the positive half cycle of alternating current, a leakage voltage positive electrode forms a unidirectional loop through a diode D1, an input end of an optocoupler U1, a resistor R1 and a leakage voltage negative electrode, the optocoupler U1 is driven to output a leakage PULSE signal PULSE, and in the negative half cycle of alternating current, the diode D1 is reversely cut off, and the unidirectional loop is not conducted.
4. A circuit for detecting leakage via a leakage voltage according to claim 1, wherein the pulse filter circuit comprises a resistor R8 and a capacitor C20, the other end of the resistor R8 is connected to one end of the capacitor C20 and one end of the resistor R9, and the other end of the capacitor C20 is grounded.
5. The circuit for detecting leakage through a leakage voltage according to claim 1, wherein the analog amplifying circuit comprises an operational amplifier U2A, the other end of a resistor R9 is connected to a positive input end of the operational amplifier U2A, an output end of the operational amplifier U2A is connected to one end of a resistor R7 and one end of a capacitor C19, and is connected to a negative input end of the operational amplifier U2A through a resistor R3, the other end of the capacitor C19 is grounded, the other end of the resistor R7 is grounded through a resistor R10, the output end of the operational amplifier U2A forms a voltage dividing circuit by using the resistor R7 and the resistor R10, and the negative input end of the operational amplifier U2A is grounded through a resistor R6; the operational amplifier U2A amplifies the leakage PULSE signal PULSE, isolates the leakage PULSE signal PULSE from a later-stage circuit, and the capacitor C19 performs smooth filtering on the output signal of the operational amplifier U2A.
6. The circuit for detecting leakage through a leakage voltage according to claim 1, wherein the circuit comprises a display circuit, the display circuit comprises an NPN triode Q2, a light emitting diode D3, a resistor R13 and a resistor R14, the other end of the resistor R14 is connected with the B pole of the Q2, the E pole of the Q2 is grounded, the C pole of the Q2 is connected with one end of the resistor R13, VCC is connected with the positive pole of the light emitting diode D3, and the negative pole of the light emitting diode D3 is connected with the other end of the resistor R13; when the OUTPUT voltage level_output is high, the NPN transistor Q2 is turned on, and the diode D3 is turned on, indicating that the leakage voltage is detected.
7. A method of detecting leakage by means of a leakage voltage, implemented on the basis of a circuit according to any one of claims 1-6, characterized in that the method comprises:
s1, the leakage voltage is converted into a leakage PULSE signal PULSE through the optocoupler isolation circuit;
s2, the PULSE filtering circuit filters leakage PULSE signals, when the width of the leakage PULSE signals is smaller than the preset time, the PULSE is filtered, and only high-level PULSE which is larger than the preset time can smoothly pass through the PULSE filtering circuit;
s3, the analog amplifying circuit carries out amplitude conditioning on the filtered pulse signals;
s4, the trigger release circuit is used for converting the pulse signal subjected to amplitude conditioning into a level signal
Level_output and latches or releases the LEVEL signal level_output.
8. The method for detecting leakage through a leakage voltage according to claim 7, wherein the method for latching or releasing the trigger hold-down circuit is as follows:
when the control signal Unlock is low LEVEL and the voltage division is larger than the threshold voltage, the OUTPUT voltage LEVEL_OUTPUT of the trigger unit is high LEVEL, so that the LEVEL_OUTPUT high LEVEL signal is latched;
when the Unlock signal is at high LEVEL, the input end of the trigger unit is 0V, and the OUTPUT voltage level_output is at low LEVEL, so as to release the level_output signal.
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| CN112798985B (en) * | 2019-10-28 | 2022-07-26 | 上海度普新能源科技有限公司 | Battery pack voltage line sequence detection circuit |
| CN113625021B (en) * | 2020-05-06 | 2022-10-18 | 比亚迪股份有限公司 | Protection device, method and equipment for electric leakage detection resistor |
| CN113848503A (en) * | 2020-06-28 | 2021-12-28 | 中兴通讯股份有限公司 | Connection detection circuit, alarm device and base station |
| CN116027159B (en) * | 2023-01-30 | 2023-08-25 | 宁波群芯微电子股份有限公司 | Optocoupler voltage-resistant quality control method and optocoupler voltage-resistant test circuit |
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