A water-immersion electric shock protection device

Abstract

The embodiment of the present invention discloses a water-immersion anti-electric shock leakage protector, which includes a 220V AC input terminal J1, a 220V AC output terminal J2, a current transformer PL1, a current zero-crossing detection comparator circuit, a leakage signal analysis circuit, and a first power supply on-off control circuit. The detected electric shock signal can be analyzed to intelligently identify whether it is physical leakage or human leakage. The physical leakage protection current is 30-50MA, the human leakage protection current is 0.5-20MA, and the protection breaking time is 5-10 milliseconds to ensure personal safety.

Description

Technical Field

[0001] The embodiment of the present invention relates to the technical field of leakage protection equipment, and specifically to a water-immersion anti-electric shock leakage protector. Background Art

[0002] Since humans invented and used electricity, it has not only brought a lot of convenience to humans, but also brought disasters to humans. It may burn electrical appliances, cause fires, or give people electric shocks. In the process of using electricity, personal electric shocks and fires caused by the shortcomings of electrical equipment itself, improper use, and ineffective safety technical measures have caused unnecessary losses to people's lives and property. In daily life, electrical accidents caused by improper use of electrical equipment or line leakage occur from time to time. Leakage of low-voltage distribution system lines, leakage of electrical equipment, overload and short circuit, or heating caused by grounding current flowing through metal welds may all lead to safety hazards. According to incomplete statistics, thousands of people die from electric shock accidents in my country every year, and the economic losses caused by fires caused by leakage amount to hundreds of millions of yuan. It has become a top priority to prevent personal electric shocks caused by leakage and damage to power supply lines or even fires caused by grounding faults. Ordinary leakage protection switches do not detect and distinguish between physical leakage and human electric shock. The unified protection breaking time is 50-100 microseconds, and the leakage protection current is about 30mA. When the current passing through the human body reaches 8-10mA, it is difficult for the hand to get rid of the electrode, and there is severe pain (finger joints). 20-25mA The hand quickly becomes paralyzed and cannot automatically get rid of the electrode, and it is difficult to breathe. 50-80mA has difficulty breathing and the atrium begins to tremble. 90-100mA respiratory paralysis, and the heart begins to be paralyzed after three seconds and stops beating. When the human body is subjected to excessive current, the power supply must be disconnected in the shortest time to prevent the risk of electric shock. The existing leakage protection switch cannot play a good protective role in the event of a single-phase electric shock accident. Summary of the invention

[0003] To this end, an embodiment of the present invention provides a water-immersion anti-electric shock leakage protector to solve the problem that the existing leakage protection switch cannot play a good protective role when a single-phase electric shock accident occurs to the human body.

[0004] In order to achieve the above-mentioned purpose, the embodiment of the present invention provides the following technical solutions: a water-immersion anti-electric shock leakage protector, the leakage protector includes a 220V AC input terminal J1, a 220V AC output terminal J2, a current transformer PL1, a current zero-crossing detection comparator circuit, a leakage signal analysis circuit and a first power supply on-off control circuit, the 220V AC input terminal and the 220V AC output terminal are connected through a live wire and a neutral wire, the 220V AC output terminal is used to connect a load circuit, the live wire and the neutral wire pass through the center of the current transformer PL1 The current zero-crossing detection comparator current includes a dual operational amplifier U2, the detection coil of the current transformer PL1 is connected to the input end of the dual operational amplifier U2, the leakage signal analysis circuit includes a single-chip microcomputer U1, the output end of the dual operational amplifier is connected to the single-chip microcomputer U1, the first power on-off control circuit includes an optical coupler U3, a relay K1 and a relay K2, the single-chip microcomputer U1 is connected to the working coils of the relay K1 and the relay K2 through the optical coupler U3, and the normally open contacts of the relay K1 and the relay K2 are respectively connected in series to the neutral line and the live line.

[0005] Furthermore, the model of the single chip microcomputer U1 is STC12C5608AD, and the model of the dual operational amplifier U2 is LM358.

[0006] Furthermore, one end of the detection coil of the current transformer PL1 is connected to the in-phase input pin 3 and the inverting input pin 6 of the dual operational amplifier U2 through the J3_6 port of the terminal J3, and the other end of the detection coil of the current transformer PL1 is connected to the inverting input pin 2 and the in-phase input pin 5 of the dual operational amplifier U2 through the J3_5 port of the terminal J3, and the output pin 1 and pin 7 of the dual operational amplifier U2 are connected to the P1.7 port and the P3.7 port of the single-chip microcomputer U1, and the P1.0 port of the single-chip microcomputer U1 is connected to the optocoupler U3 through the J3_7 port of the terminal J3. The output end of the optocoupler U3 is connected to the working coil of the relay K1 and the working coil of the relay K2 in sequence through the collector of the transistor Q2 and is connected to the power supply end V+. The normally open contact of the relay K1 and the normally open contact of the relay K2 are respectively connected in series to the neutral line and the live line. A full-wave rectifier U7 is connected between the live line and the neutral line of the 220V AC input terminal J1, and the power supply end V+ is connected to the V+ end of the full-wave rectifier. A voltage regulator diode D2 and a filter capacitor C3 are connected between the V+ end and the V- end of the full-wave rectifier U7, and the V- end of the full-wave rectifier U7 is grounded.

[0007] Furthermore, the leakage protector also includes a zero-live short-circuit current limiting and arc-free protection circuit, which includes a load short-circuit and overcurrent detection circuit and a second power on-off control circuit, and the load short-circuit and overcurrent detection circuit includes diodes D3 and D6, the positive electrode of diode D3 is connected to the live wire input end, the positive electrode of diode D6 is connected to the live wire output end, and the negative electrodes of diodes D3 and D6 are both connected to the P3.2 port of the microcontroller U1 via the J3_15 port of terminal J3, and the second power on-off control circuit includes multiple groups of MOS field effect tube groups connected in parallel between the live wire input end and the live wire output end, each group of MOS field effect tube groups includes two MOS field effect tubes connected in series, and the gates G of multiple MOS field effect tubes are all connected to the microcontroller U1.

[0008] Further, the second power on / off control circuit includes four MOS field effect transistors Q1, Q6, Q3 and Q10, the drain S of the MOS field effect transistor Q1 and the drain S of Q6 are connected in series, the drain S of the MOS field effect transistor Q3 and the drain S of Q10 are connected in series, one end of the two parallel MOS field effect transistor groups is connected to the live wire input end through the source D of Q1 and Q3, and the other end is connected to the live wire output end after being connected in series to the normally open contact of the relay K2 through the source D of Q6 and Q10, the P3.3 port of the single-chip computer U1 is connected to the base of the transistors Q7 and Q8 via the J3_17 port of the terminal J3, and the P3.3 port of the single-chip computer U1 is used to trigger the MOS tube The transistor Q7 is turned on to supply power to the load output, the collector of the transistor Q7 is connected to the gate G of the MOS field effect transistors Q1 and Q6, the collector of the transistor Q8 is connected to the gate G of the MOS field effect transistors Q3 and Q10, the gate Gs of the MOS field effect transistors Q1, Q6, Q3 and Q10 are respectively connected to the transistor Q5 and the transistor Q9 and are respectively connected to the P3.4 port and the P3.5 port of the single-chip computer U1 through the J3_18 port and the J3_19 port of the terminal J3, and the P3.4 port and the P3.5 port of the single-chip computer U1 are respectively used for the on and off drive signal control of the MOS field effect transistors Q1, Q6, Q3 and Q10 when the AC passes through zero.

[0009] Furthermore, the leakage protector also includes a surge current suppression circuit, which includes a transformer T1 and an NTC thermistor, one end of the primary coil of the transformer T1 is connected to the power supply terminal V+, and the other end is connected to the collector of the transistor Q8, one end of the secondary coil of the transformer T1 is connected to the NTC thermistor, and the other end is grounded, the NTC thermistor is connected to the input end of the optocoupler U6, the output end of the optocoupler U6 is connected to the base of the transistor Q6, the emitter of the transistor Q8 is grounded, the collector of the transistor Q8 is connected to the collector of the transistor Q6 and the connection point of the two is connected to the power supply terminal V+, and the base of the transistor Q8 is connected to the emitter of the transistor Q6.

[0010] Furthermore, the NTC thermistor is connected to the VCC terminal and the VDD terminal in sequence, the VCC terminal is connected to the VCC terminal of the single-chip computer U1, the connection point between the NTC thermistor and the VDD terminal is connected to the cathode of the Zener diode D1, the anode of the Zener diode D1 is grounded, the positive electrode of the capacitor C16 is connected between the VCC terminal and the VDD terminal, the negative electrode of C16 is grounded, the connection point between the VDD terminal and the NTC thermistor is connected to the positive electrode of the capacitor C3, and the negative electrode of the capacitor C3 is grounded.

[0011] Furthermore, the leakage protector also includes an overvoltage and undervoltage detection circuit, and the overvoltage and undervoltage control circuit includes a full-wave rectifier U4 and an optocoupler U5. The two AC input ends of the full-wave rectifier U4 are respectively connected to the live wire and the neutral wire of the 220V AC input terminal J1, and the V+ and V- ends of the full-wave rectifier U4 are connected to the input end of the optocoupler U5. The output end of the optocoupler U5 is connected to the P1.1 port of the microcontroller U1 via the J3_8 port of the terminal J3.

[0012] The embodiments of the present invention have the following advantages:

[0013] An embodiment of the present invention provides a water-immersion anti-electric shock leakage protector, which includes a 220V AC input terminal J1, a 220V AC output terminal J2, a current transformer PL1, a current zero-crossing detection comparator circuit, a leakage signal analysis circuit, and a first power supply on-off control circuit. The leakage protector can analyze the detected electric shock signal to intelligently identify whether it is physical leakage or human leakage, and timely control the relay K1 and the relay K2 to disconnect the load output when the leakage current value reaches the corresponding preset threshold value. The physical leakage protection current 3 0-50MA, human body leakage protection current 0.5-20MA, protection breaking time 5-10 milliseconds, ensuring personal safety; when the neutral and live wires at the load output end or the ordinary socket are immersed in water at the same time, the neutral and live wires form a loop through the water. At this time, the water is conductive and charged, but it does not reach the protection action value. It is a physical leakage and no loop is formed with the earth. The protector will not act to cut off the power. When a human body stands on the ground and touches the water, it is detected that the human body has an electric shock current of more than 0.5MA. The protector will issue a command to disconnect the load output to prevent electric shock due to immersion in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0015] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0016] Figure 1 A circuit diagram of a water-immersion electric shock protection leakage protector provided in Example 1 of the present invention;

[0017] Figure 2 Another circuit diagram of a water-immersion electric shock protection leakage protector provided in Embodiment 1 of the present invention;

[0018] Figure 3 Another circuit diagram of a water-immersion anti-electric shock leakage protector provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0019] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 , Figure 2 and Figure 3As shown, this embodiment proposes a water-immersion anti-electric shock leakage protector, which includes a 220V AC input terminal J1, a 220V AC output terminal J2, a current transformer PL1, a current zero-crossing detection comparator circuit, a leakage signal analysis circuit and a first power on-off control circuit. The 220V AC input terminal and the 220V AC output terminal are connected through a live wire and a neutral wire, and the 220V AC output terminal is used to connect the load circuit. The live wire and the neutral wire pass through the center hole of the current transformer PL1. The current zero-crossing detection comparator current includes a dual operational amplifier U2, and the detection coil of the current transformer PL1 is connected to the input end of the dual operational amplifier U2. The leakage signal analysis circuit includes a single-chip microcomputer U1, and the output end of the dual operational amplifier is connected to the single-chip microcomputer U1. The first power on-off control circuit includes an optical coupler U3, a relay K1 and a relay K2. The single-chip microcomputer U1 is connected to the working coils of the relay K1 and the relay K2 through the optical coupler U3, and the normally open contacts of the relay K1 and the relay K2 are respectively connected in series to the neutral wire and the live wire. The single chip computer U1 is used to analyze the detected electric shock signal to intelligently identify whether it is physical leakage or human body leakage, and according to the identification result, when the leakage current value reaches the corresponding preset threshold, timely control relay K1 and relay K2 to disconnect the load output.

[0021] In this embodiment, the model of the single-chip microcomputer U1 is STC12C5608AD, with a built-in A / D converter sample, 2 sampling comparators, a fast conversion time of up to 80ns, a sampling frequency of 22.1184MSPS, an I / O level range of 0.25V~Vdvdd(5V)-0.4V, extracting electric shock characteristics, determining human body electric shock, and sending a signal to activate the protection device. The comparator is triggered to turn on and off using the fault mode recognition signal, thereby controlling the opening and closing of the electromagnetic relay to open and close the conductive circuit. Use the model SRA-24VDC-CL electromagnetic relay or a relay with greater power and high performance.

[0022] In this embodiment, the model of the dual operational amplifier U2 is LM358. Pin 1 is the output terminal, pin 2 is the inverting input terminal, pin 3 is the non-inverting input terminal, pin 4 is the negative power supply (when dual power supply is working) or ground (when single power supply is working), pin 5 is the non-inverting input terminal, pin 6 is the inverting input terminal, pin 7 is the output terminal, pin 8 is the positive power supply, pins 1, 2, and 3 are an operational amplifier channel, and pins 5, 6, and 7 are another operational amplifier channel. The LM358 internally includes two independent, high-gain, internal frequency-compensated dual operational amplifiers. Working principle: The voltage of pin 2 is compared with the voltage of pin 3, and the voltage of pin 6 is compared with the voltage of pin 5, which correspond to two independent outputs respectively: when 1IN+ is greater than 1IN-2IN+ is greater than 2IN-, 1OUT 2OUT outputs a high level. When 1IN+ is less than 1IN-2IN+ is less than 2IN-, 1OUT 2OUT outputs a low level. The induced current signal is collected by the current transformer PL1 and input into the 3rd and 6th pins of the dual operational amplifier U2 comparator. The 5th pin is the positive voltage reference, the 2nd pin is the negative voltage reference, and the 1st and 7th pins are output to the microcontroller U1 for analysis.

[0023] Figure 1 Middle terminal J3, Figure 2 Terminal J2 and Figure 3 Specifically, one end of the detection coil of the current transformer PL1 is connected to the in-phase input pin 3 and the inverting input pin 6 of the dual operational amplifier U2 through the J3_6 port of the terminal J3, and the other end of the detection coil of the current transformer PL1 is connected to the inverting input pin 2 and the in-phase input pin 5 of the dual operational amplifier U2 through the J3_5 port of the terminal J3. The output pins 1 and 7 of the dual operational amplifier U2 are connected to the P1.7 and P3.7 ports of the microcontroller U1, and the P1.0 port of the microcontroller U1 is connected to the input of the optocoupler U3 through the J3_7 port of the terminal J3. The output end of the optocoupler U3 is connected to the working coil of the relay K1 and the working coil of the relay K2 in sequence through the collector of the transistor Q2 and is connected to the power supply end V+. The normally open contact of the relay K1 and the normally open contact of the relay K2 are respectively connected in series to the neutral line and the live line. A full-wave rectifier U7 is connected between the live line and the neutral line of the 220V AC input terminal J1, the power supply end V+ is connected to the V+ end of the full-wave rectifier U7, a voltage regulator diode D2 and a filter capacitor C3 are connected between the V+ end and the V- end of the full-wave rectifier U7, and the V- end of the full-wave rectifier U7 is grounded.

[0024] When the electrical equipment is operating normally, the current in the line is balanced, and the sum of the current vectors in the PL1 transformer is zero (the current is a directional vector, such as the outflow direction is "+" and the return direction is "-". The currents flowing back and forth in the transformer are equal in magnitude and opposite in direction, and the positive and negative cancel each other out). Since there is no residual current in the primary coil, the secondary coil will not be induced, and the K1 and K2 relays are in a closed state. When someone is electrocuted or other ground leakage faults occur, due to the presence of leakage current, the phase sum of the load currents (including the neutral line current) of each phase on the primary side of the leakage transformer is no longer zero, and residual current is generated in the primary coil, so it will induce the secondary coil. When this current value reaches the action current value specified by the leakage protector after amplification and analysis by U2, the K1 and K2 relays will trip and disconnect the load circuit. The protection circuit of the leakage protector can quickly and accurately identify the characteristics of electric shock, and accurately distinguish between ordinary electric shock / leakage and electric shock to the human body. The basic basis is the parameters of biological tissue impedance. The human body is a living organism, mainly composed of muscles, skin, blood, etc. If the impedance at three different frequencies is detected, the characteristics of human electric shock are identified by the MCU (digital-analog signal processing). The total impedance of the human body is mainly determined by the skin impedance. By setting a safety threshold, it is determined that a human electric shock accident has occurred when the coefficient is lower than this threshold. When electric shock has occurred, it is required to cut off the current in the shortest time. If the human body touches the line end of the power supply, that is, the live wire, or there is leakage inside the electrical equipment, the circuit breaker will immediately trip after detecting this part of the current difference to protect the safety of the person and the electrical equipment.

[0025] When the neutral and live wires at the load output end or the ordinary socket are immersed in water at the same time, the neutral and live wires form a loop through the water. At this time, the water is conductive and charged, but it does not reach the protection action value. It is a physical leakage and does not form a loop with the earth. The protector will not operate to cut off the power. When a person stands on the ground and touches the water, it is detected that the human body has an electric shock current of more than 0.5MA. The protector will issue a command to disconnect the load output to achieve the function of preventing electric shock from immersion.

[0026] The leakage protector also includes a zero-live short-circuit current-limiting arc-free protection circuit, which includes a load short-circuit and overcurrent detection circuit and a second power supply on-off control circuit. The load short-circuit and overcurrent detection circuit includes diodes D3 and D6, the positive electrode of diode D3 is connected to the live wire input end, the positive electrode of diode D6 is connected to the live wire output end, the negative electrodes of diodes D3 and D6 are both connected to the P3.2 port of the single-chip computer U1 through the J3_15 port of terminal J3, and the second power supply on-off control circuit includes multiple groups of MOS field effect tube groups connected in parallel between the live wire input end and the live wire output end, each group of MOS field effect tube groups includes two MOS field effect tubes connected in series, and the gates G of the multiple MOS field effect tubes are all connected to the single-chip computer U1.

[0027] In this embodiment, the second power on / off control circuit includes four MOS field effect transistors Q1, Q6, Q3 and Q10, the drain S of the MOS field effect transistor Q1 and the drain S of Q6 are connected in series, the drain S of the MOS field effect transistor Q3 and the drain S of Q10 are connected in series, one end of the two parallel MOS field effect transistor groups is connected to the live wire input end through the source D of Q1 and Q3, and the other end is connected to the live wire output end after being connected in series to the normally open contact of the relay K2 through the source D of Q6 and Q10, the P3.3 port of the single-chip computer U1 is connected to the base of the transistors Q7 and Q8 via the J3_17 port of the terminal J3, and the P3.3 port of the single-chip computer U1 is used to trigger the MO The S tube is turned on to supply power to the load output, the collector of the transistor Q7 is connected to the gate G of the MOS field effect transistors Q1 and Q6, the collector of the transistor Q8 is connected to the gate G of the MOS field effect transistors Q3 and Q10, the gate G of the MOS field effect transistors Q1, Q6, Q3 and Q10 are respectively connected to the transistor Q5 and the transistor Q9 and are respectively connected to the P3.4 port and the P3.5 port of the microcontroller U1 through the J3_18 port and the J3_19 port of the terminal J3, the P3.4 port and the P3.5 port of the microcontroller U1 are respectively used for the on and off drive signal control of the MOS field effect transistors Q1, Q6, Q3 and Q10 when the AC passes through zero.

[0028] When leakage or overvoltage or undervoltage occurs, two relays K1 and K2 control the on and off. The four MOS field effect tubes Q1, Q6 and Q3, Q10 are mainly used to quickly cut off or open the power supply within 10MS when the load is short-circuited or overcurrent occurs. The on and off of the AC circuit is controlled by the gate G signal voltage. When the gate G voltages of the four MOS field effect tubes are positive biased at the same time, the AC circuit is open. When the gate G voltages of the four power field effect tubes are zero biased at the same time, the AC circuit is disconnected. During normal operation, the microcontroller Q1, Q6 and Q3, Q10 are turned on. When the microcontroller U1 detects a load short circuit or overcurrent signal, the P3.2 port of the microcontroller U1 detects the signal. At this time, the microcontroller P1.2 port (the P1.2 port is the power switch port, connected to terminal J5, with an external push button switch for the on-off switch of the protector) outputs a low voltage when the AC passes through zero, and the G poles of the four MOS field effect tubes are pulled down and closed. The microcontroller U1 controls Q1, Q6 and Q3, Q10 to turn off, disconnecting the load output. In order to ensure that the four MOS field effect tubes Q1, Q6 and Q3, Q10 are protected from the impact of instantaneous peak voltage and current, the gate G DC switch signal of the four MOS field effect tubes Q1, Q6 and Q3, Q10 performs auxiliary control of AC zero-crossing opening and AC zero-crossing closing, that is, whether controlling the output load on or off, the control action is when the AC crosses zero. The AC zero-crossing detection obtains a square wave signal synchronized with the grid input phase voltage signal through the zero-crossing comparator composed of dual operational amplifiers LM393. The signal is sent to the interrupt pin of the MCU chip for zero-crossing control. When the neutral line and the live line are directly short-circuited, the leakage protector disconnects the circuit within 0.01 seconds to achieve zero-crossing protection to prevent fire. After the fault is eliminated, the leakage protector will automatically restore power supply within 30 seconds.

[0029] The leakage protector also includes a surge current suppression circuit, which includes a transformer T1 and an NTC thermistor. One end of the primary coil of the transformer T1 is connected to the power supply terminal V+, and the other end is connected to the collector of the transistor Q8. One end of the secondary coil of the transformer T1 is connected to the NTC thermistor, and the other end is grounded. The NTC thermistor is connected to the input end of the optocoupler U6, and the output end of the optocoupler U6 is connected to the base of the transistor Q6. The emitter of the transistor Q8 is grounded, the collector of the transistor Q8 is connected to the collector of the transistor Q6 and the connection point of the two is connected to the power supply terminal V+, and the base of the transistor Q8 is connected to the emitter of the transistor Q6. The NTC thermistor is connected to the VCC terminal and the VDD terminal in sequence, the VCC terminal is connected to the VCC terminal of the microcontroller U1, the connection point of the NTC thermistor and the VDD terminal is connected to the cathode of the Zener diode D1, the anode of the Zener diode D1 is grounded, the positive electrode of the capacitor C16 is connected between the VCC terminal and the VDD terminal, the negative electrode of C16 is grounded, the connection point of the VDD terminal and the NTC thermistor is connected to the positive electrode of the capacitor C3, and the negative electrode of the capacitor C3 is grounded.

[0030] Transformer T1 is connected in series with an NTC negative temperature coefficient thermistor for power surge suppression. At the moment the circuit power is turned on, a surge current many times higher than that in normal operation will be generated in the circuit, and the initial resistance of the NTC thermistor is large, which can suppress the excessive current in the circuit, thereby protecting its power circuit and load. The current of the D1 voltage stabilizing diode can change in a wide range while the voltage remains basically unchanged, which plays a voltage stabilizing role. A stable voltage is obtained by parallel filtering of C16 and C3 to supply the MCU. When the circuit enters the normal working state, the temperature of the thermistor rises due to the current passing through it, and the resistance value drops to a very small value, which will not affect the normal operation of the circuit.

[0031] The leakage protector also includes an overvoltage and undervoltage detection circuit. The overvoltage and undervoltage control circuit includes a full-wave rectifier U4 and an optocoupler U5. The two AC input ends of the full-wave rectifier U4 are respectively connected to the live wire and the neutral wire of the 220V AC input terminal J1. The V+ and V- ends of the full-wave rectifier U4 are connected to the input end of the optocoupler U5. The output end of the optocoupler U5 is connected to the P1.1 port of the microcontroller U1 via the J3_8 port of the terminal J3. The default setting is 150V-270V as the normal output. If this value range is exceeded, the relay will disconnect the output. After power-on, the protector automatically detects overvoltage, undervoltage, leakage, and short circuit faults at the output and input ends. When the voltage between the live and neutral wires at the input end is greater than 270V or the set value, the gate will automatically close for protection and sound and light warnings will be given. Undervoltage protection: When the voltage between the neutral and live wires at the input end is less than 150V or the set value, the switch will automatically close (close relays K1 and K2) for protection and sound and light warnings will be given, and the switch will automatically close and supply power until the voltage returns to normal.

[0032] The leakage protector proposed in this embodiment is a water-immersion anti-electric shock leakage protector, which can analyze the detected electric shock signal to intelligently identify whether it is physical leakage or human leakage. The physical leakage protection current is 30-50MA, the human leakage protection current is 0.5-20MA, and the protection disconnection time is 5-10 milliseconds to ensure personal safety. When the neutral wire and the live wire are directly short-circuited, the leakage protector disconnects the circuit within 0.01 seconds, achieving zero-crossing protection to prevent fire. After the fault is eliminated, the leakage protector will automatically restore power supply within 30 seconds. An ordinary socket can be put into water, and the human body will not feel electric shock when touching the water. When the leakage current is above 0.5MA or the set value, the protector automatically disconnects from the power supply to ensure personal safety. After power-on, the protector automatically detects overvoltage, undervoltage, leakage, and short-circuit faults at the output and input terminals. When the voltage between the zero and live wires at the input terminal is greater than 270V or the set value, it automatically closes the gate for protection and sounds a warning. Undervoltage protection: When the voltage between the neutral and live wires at the input end is less than 150V or the set value, the circuit breaker will automatically close for protection and issue an audible and visual warning until the voltage returns to normal and the circuit breaker will automatically close for power supply.

[0033] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A water-immersion electric shock protection device, characterized in that: The leakage protector includes a 220V AC input terminal J1, a 220V AC output terminal J2, a current transformer PL1, a current zero-crossing detection comparator circuit, a leakage signal analysis circuit and a first power on-off control circuit. The 220V AC input terminal and the 220V AC output terminal are connected through a live wire and a neutral wire. The 220V AC output terminal is used to connect a load circuit. The live wire and the neutral wire pass through the center hole of the current transformer PL1. The current zero-crossing detection comparator circuit includes a dual operational amplifier U2. The detection coil of the current transformer PL1 is connected to the input end of the dual operational amplifier U2. The leakage signal analysis circuit includes a single-chip microcomputer U1. The output end of the dual operational amplifier is connected to the single-chip microcomputer U1. The first power on-off control circuit includes an optical coupler U3, a relay K1 and a relay K2. The single-chip microcomputer U1 is connected to the working coils of the relay K1 and the relay K2 through the optical coupler U3. The normally open contacts of the relay K1 and the relay K2 are connected in series to the neutral wire and the live wire respectively. The model of the single chip microcomputer U1 is STC12C5608AD, and the model of the dual operational amplifier U2 is LM358; One end of the detection coil of the current transformer PL1 is connected to the in-phase input pin 3 and the inverting input pin 6 of the dual operational amplifier U2 through the J3_6 port of the terminal J3, and the other end of the detection coil of the current transformer PL1 is connected to the inverting input pin 2 and the in-phase input pin 5 of the dual operational amplifier U2 through the J3_5 port of the terminal J3. The output pin 1 and pin 7 of the dual operational amplifier U2 are connected to the P1.7 port and the P3.7 port of the single-chip microcomputer U1. The P1.0 port of the single-chip microcomputer U1 is connected to the input of the optical coupler U3 through the J3_7 port of the terminal J3. The output end of the optical coupler U3 is connected to the working coil of the relay K1 and the working coil of the relay K2 in sequence through the collector of the transistor Q2 and is connected to the power supply end V+. The normally open contact of the relay K1 and the normally open contact of the relay K2 are respectively connected in series to the neutral line and the live line. A full-wave rectifier U7 is connected between the live line and the neutral line of the 220V AC input terminal J1. The power supply end V+ is connected to the V+ end of the full-wave rectifier. A voltage regulator diode D2 and a filter capacitor C3 are connected between the V+ end and the V- end of the full-wave rectifier U7. The V- end of the full-wave rectifier U7 is grounded. The leakage protector also includes a zero-live short-circuit current-limiting arc-free protection circuit, which includes a load short-circuit and overcurrent detection circuit and a second power supply on-off control circuit. The load short-circuit and overcurrent detection circuit includes diodes D3 and D6, the positive electrode of the diode D3 is connected to the live wire input end, the positive electrode of the diode D6 is connected to the live wire output end, and the negative electrodes of the diodes D3 and D6 are connected to the P3.2 port of the single-chip computer U1 through the J3_15 port of the terminal J3. The second power supply on-off control circuit includes multiple groups of MOS field effect tube groups connected in parallel between the live wire input end and the live wire output end, each group of MOS field effect tube groups includes two MOS field effect tubes connected in series, and the gates G of the multiple MOS field effect tubes are connected to the single-chip computer U1; The second power on / off control circuit includes four MOS field effect transistors Q1, Q6, Q3 and Q10, the drain S of the MOS field effect transistor Q1 and the drain S of Q6 are connected in series, the drain S of the MOS field effect transistor Q3 and the drain S of Q10 are connected in series, one end of the two parallel MOS field effect transistor groups is connected to the live wire input end through the source D of Q1 and Q3, and the other end is connected to the live wire output end after being connected in series to the normally open contact of the relay K2 through the source D of Q6 and Q10, the P3.3 port of the single-chip computer U1 is connected to the base of the transistors Q7 and Q8 via the J3_17 port of the terminal J3, and the P3.3 port of the single-chip computer U1 is used to trigger the MOS tube to turn on To supply power to the load output, the collector of the transistor Q7 is connected to the gates G of the MOS field effect transistors Q1 and Q6, the collector of the transistor Q8 is connected to the gates G of the MOS field effect transistors Q3 and Q10, the gates G of the MOS field effect transistors Q1, Q6, Q3 and Q10 are respectively connected to the transistors Q5 and Q9 and are respectively connected to the P3.4 port and the P3.5 port of the single-chip computer U1 through the J3_18 port and the J3_19 port of the terminal J3, and the P3.4 port and the P3.5 port of the single-chip computer U1 are respectively used for opening and closing the driving signal control of the MOS field effect transistors Q1, Q6, Q3 and Q10 when the AC passes through zero.

2. The water-immersion anti-electric shock leakage protector according to claim 1, characterized in that: The leakage protector also includes a surge current suppression circuit, which includes a transformer T1 and an NTC thermistor. One end of the primary coil of the transformer T1 is connected to the power supply terminal V+, and the other end is connected to the collector of the transistor Q8. One end of the secondary coil of the transformer T1 is connected to the NTC thermistor, and the other end is grounded. The NTC thermistor is connected to the input end of the optocoupler U6, the output end of the optocoupler U6 is connected to the base of the transistor Q6, the emitter of the transistor Q8 is grounded, the collector of the transistor Q8 is connected to the collector of the transistor Q6 and the connection point of the two is connected to the power supply terminal V+, and the base of the transistor Q8 is connected to the emitter of the transistor Q6.

3. The water-immersion anti-electric shock leakage protector according to claim 1, characterized in that: The NTC thermistor is connected to the VCC terminal and the VDD terminal in sequence, the VCC terminal is connected to the VCC terminal of the single-chip computer U1, the connection point between the NTC thermistor and the VDD terminal is connected to the cathode of the Zener diode D1, the anode of the Zener diode D1 is grounded, the positive electrode of the capacitor C16 is connected between the VCC terminal and the VDD terminal, the negative electrode of C16 is grounded, the connection point between the VDD terminal and the NTC thermistor is connected to the positive electrode of the capacitor C3, and the negative electrode of the capacitor C3 is grounded.

4. The water-immersion anti-electric shock leakage protector according to claim 1, characterized in that: The leakage protector also includes an overvoltage and undervoltage detection circuit, which includes a full-wave rectifier U4 and an optocoupler U5. The two AC input ends of the full-wave rectifier U4 are respectively connected to the live wire and the neutral wire of the 220V AC input terminal J1, the V+ end and the V- end of the full-wave rectifier U4 are connected to the input end of the optocoupler U5, and the output end of the optocoupler U5 is connected to the P1.1 port of the microcontroller U1 via the J3_8 port of the terminal J3.

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