Ground fault circuit breaker with automatic monitoring function

Abstract

The invention discloses a ground fault circuit breaker with an automatic monitoring function. The ground fault circuit breaker comprises a ground fault circuit breaking module, an automatic monitoring circuit and an automatic and manual electric leakage detection circuit. After the reset button RESET and the test button TEST are pressed down, when the tripping time of the ground fault circuit breaker exceeds a set threshold value, the MCU judges that breaking is overtime, the fifth pin of the MCU outputs an intermittent voltage, and at the moment, the end-of-life alarm lamp R shows a flashing red alarm lamp. Compared with the prior art, the grounding fault circuit breaker solves the problem that an existing grounding fault circuit breaker cannot monitor whether tripping time is normal or not.

Description

Technical Field

[0001] The invention relates to the technical field of ground fault circuit breakers, and in particular to a ground fault circuit breaker with an automatic monitoring function. Background Art

[0002] A ground fault circuit interrupter (GFCI) is a new type of circuit breaker that prevents damage to a house's wiring and protects people from electric shock. A GFCI constantly monitors the current in the neutral and hot wires of a circuit. When everything is normal, the current in both wires should be exactly the same. If the hot wire is directly connected to ground (for example, if someone accidentally touches the hot wire), the current in the hot wire will suddenly increase, while the neutral wire will not. When the GFCI detects this situation, it immediately cuts off the circuit to prevent electric shock injuries and deaths. Because the GFCI does not need to wait for the current to rise to dangerous levels before taking action, it can react much faster than traditional circuit breakers.

[0003] A test button is usually provided on the ground fault circuit breaker. By pressing the test button, the residual current test can be implemented to prevent electric shock and fire caused by ground arc.

[0004] The existing ground fault circuit breaker has a single function. Pressing the test button can only test the residual current, but cannot monitor whether the tripping time is normal. Summary of the invention

[0005] The purpose of the present invention is to provide a ground fault circuit breaker with an automatic monitoring function to solve the problem that the existing ground fault circuit breaker cannot monitor whether the tripping time is normal.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: a ground fault circuit breaker with automatic monitoring function, comprising:

[0007] A ground fault circuit breaker module, which includes a mutual inductor coil L2, a mutual inductor coil L1, a chip U1, a bridge rectifier D1, a switching power supply circuit and an electromagnetic tripping circuit, wherein the mutual inductor coil L2 is connected to the chip U1, the mutual inductor coil L1 is connected to the chip U1, the switching power supply circuit includes a resistor R2, a resistor R5 and a capacitor C6, and the electromagnetic tripping circuit includes an LB tripping coil, a diode D10 and a thyristor Q1;

[0008] The automatic monitoring circuit includes an MCU, a zero-crossing detection sampling circuit, a load voltage sampling circuit and a voltage sampling detection circuit. The load voltage sampling circuit is connected to the 9th pin of the MCU, and the voltage sampling detection circuit is connected to the 8th pin of the MCU. The load voltage sampling circuit includes a diode D8, a resistor R26 and an optical coupler U5. The diode D8 and the resistor R26 are connected in series.

[0009] An automatic and manual leakage detection circuit, which includes a reset button RESET, a test button TEST, a transistor Q2, a working indicator light G and an end-of-life alarm light R, the 7th pin of the MCU is connected to the reset button RESET, the 6th pin of the MCU is connected to the test button TEST, the transistor Q2 is connected to the 14th pin of the MCU, the collector of the transistor Q2 is connected to a resistor R25, the resistor R25 is connected to the L-polarity live wire end passing through the transformer coil, the 3rd pin of the MCU is connected to the working indicator light G, and the 5th pin of the MCU is connected to the end-of-life alarm light R;

[0010] When the reset button RESET is pressed, the load end is powered, and after being rectified by diode D8 and limited by resistor R26, it drives the input end of optocoupler U5. The output end of optocoupler U5 controls the 9th pin of MCU to become a low level, and the working indicator G connected to the 3rd pin of MCU is lit;

[0011] When the unbalanced current passing through the L and N lines of the transformer coil exceeds 6MA, the thyristor Q1 cannot be triggered, and the MCU pin 8 cannot be converted to a low level, the MCU determines that the circuit is faulty and cannot play a protective role. The MCU pin 5 outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light;

[0012] After pressing the reset button RESET, press the test button TEST. When the tripping time of the ground fault circuit breaker exceeds the set threshold, the MCU determines that the disconnection has timed out, and the 5th pin of the MCU outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light.

[0013] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0014] 1. In the present invention, the ground fault circuit breaker has manual test trip time and automatic monitoring functions. The manual test (TEST) circuit is controlled by the MCU, and the trip time is detected by the MCU. When the trip time exceeds the standard time, the red indicator light is driven to alarm, prompting replacement in time, but it will not trip directly.

[0015] 2. In the present invention, the automatic monitoring circuit realizes all-weather automatic detection through the MCU, monitoring the damage of the GFCI itself caused by damage to the leakage sensor, the neutral line repeated grounding sensor, the chip U1 and various components, power devices, trip coils and other components in the switching power supply circuit, so as to avoid safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 The diagram is a circuit connection diagram of a ground fault circuit breaker with automatic monitoring function.

[0018] Figure 2 The figure is a practical circuit diagram of a ground fault circuit breaker with automatic monitoring function.

[0019] Figure 3 The schematic diagram is a structural diagram of a ground fault circuit breaker with automatic monitoring function.

[0020] Legend:

[0021] 1. Reset button RESET: 2. Test button TEST. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "upper", "inner", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Example 1

[0028] See also Figure 1-3 The present invention provides a technical solution: a ground fault circuit breaker with automatic monitoring function, comprising:

[0029] A ground fault circuit breaker module, which includes a mutual inductor coil L2, a mutual inductor coil L1, a chip U1, a bridge rectifier D1, a switching power supply circuit and an electromagnetic tripping circuit, wherein the mutual inductor coil L2 is connected to the chip U1, the mutual inductor coil L1 is connected to the chip U1, the switching power supply circuit includes a resistor R2, a resistor R5 and a capacitor C6, and the electromagnetic tripping circuit includes an LB tripping coil, a diode D10 and a thyristor Q1;

[0030] The automatic monitoring circuit includes an MCU, a zero-crossing detection sampling circuit, a load voltage sampling circuit and a voltage sampling detection circuit. The load voltage sampling circuit is connected to the 9th pin of the MCU, and the voltage sampling detection circuit is connected to the 8th pin of the MCU. The load voltage sampling circuit includes a diode D8, a resistor R26 and an optical coupler U5. The diode D8 and the resistor R26 are connected in series.

[0031] An automatic and manual leakage detection circuit, which includes a reset button RESET1, a test button TEST2, a transistor Q2, a working indicator light G and an end-of-life alarm light R, the 7th pin of the MCU is connected to the reset button RESET1, the 6th pin of the MCU is connected to the test button TEST2, the transistor Q2 is connected to the 14th pin of the MCU, the collector of the transistor Q2 is connected to a resistor R25, the resistor R25 is connected to the L-polarity live wire end passing through the transformer coil, the 3rd pin of the MCU is connected to the working indicator light G, and the 5th pin of the MCU is connected to the end-of-life alarm light R;

[0032] When the reset button RESET1 is pressed, the load end is powered, and after being rectified by diode D8 and limited by resistor R26, it drives the input end of optocoupler U5. The output end of optocoupler U5 controls the 9th pin of MCU to become a low level, and the working indicator G connected to the 3rd pin of MCU is lit;

[0033] When the unbalanced current passing through the L and N lines of the transformer coil exceeds 6MA, the thyristor Q1 cannot be triggered, and the MCU pin 8 cannot be converted to a low level, the MCU determines that the circuit is faulty and cannot play a protective role. The MCU pin 5 outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light;

[0034] After pressing the reset button RESET1, press the test button TEST2. When the tripping time of the ground fault circuit breaker exceeds the set threshold, the MCU determines that the disconnection has timed out, and the 5th pin of the MCU outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light.

[0035] The transformer coil L2 is a leakage sensor (1000:1) transformer coil, and the transformer coil L1 is a neutral line repeated grounding sensor (200:1) transformer coil. When the transformer coil L2 senses an unbalanced current exceeding 6MA or the transformer coil L1 detects repeated grounding of the neutral line, it is coupled to the chip U1 through the resistor R4 and the capacitor C3. The pin 1 of the chip U1 outputs a high level, which triggers the thyristor Q1 through the resistor R27, triggering the circuit formed by the LB tripping coil, the diode D10, and the thyristor Q1. The iron core of the tripping coil drives the mechanical action to cut off the power supply.

[0036] When the ground fault circuit interrupter (GFCI) is reset, the load is energized and drives the input of the optocoupler U5 after rectification by diode D8 and current limiting by R26. The output controls the 9th pin of the MCU to become a low level.

[0037] When the reset button RESET1 is pressed to perform manual testing, the MCU's 7th pin turns to a low level, and the MCU's 14th pin gets a high level. After the resistor R3 limits the current, it drives the B pole of the transistor Q2, and the transistor Q2 is turned on. After passing through the resistor R25, it passes through the L polarity live wire terminal and the N neutral wire terminal of the transformer coil, and an unbalanced current of more than 6MA is obtained.

[0038] When the test button TEST2 is pressed for automatic testing, the MCU's 7th pin turns to a low level, and the MCU14th pin gets a high level. After being limited by the resistor R3, the B pole of the transistor Q2 is driven, and the transistor Q2 is turned on. After passing through the resistor R25, it passes through the L polarity live wire end and the N neutral wire end of the transformer coil, and an unbalanced current of more than 6MA is obtained. The MCU's 7th pin generates a pulse, and after being limited by the current limiting resistor R27, the B pole of the transistor Q3 is controlled. The transistor Q3 is turned on, and after passing through the resistor R14, it passes through the N polarity live wire end and the L neutral wire end of the transformer coil, and an unbalanced current of more than 6MA is obtained.

[0039] When the transformer coil senses an unbalanced current exceeding 6MA, it is coupled to the chip U1 through the resistor R4, and the pin 1 of the chip U1 outputs a high level, which triggers the thyristor Q1 to turn on through the resistor R27. The trigger current is opposite to the phase of the trip coil LB. At the same time, the thyristor Q1 is turned on, and the diode D9 releases the voltage of the MCU pin 8, which turns to a low level. The MCU determines that the circuit is normal.

[0040] The automatic monitoring circuit realizes all-weather automatic detection through the MCU, monitoring the damage of the GFCI itself caused by damage to the leakage sensor, the neutral line repeated grounding sensor, the chip U1 and various components in the switching power supply circuit, the power device, the trip coil and other components to avoid safety accidents.

[0041] Specifically, the zero-crossing detection sampling circuit includes a resistor R10 and a voltage-stabilizing diode Z1. The zero-crossing detection sampling circuit is used to detect the power supply frequency and phase, R10 plays a current limiting role, and the voltage-stabilizing diode Z1 stabilizes the voltage to protect the MCU.

[0042] Specifically, the voltage sampling detection circuit includes a diode D9, a resistor R34 and a voltage regulator diode Z3. The diode D9 and the resistor R34 are connected in parallel and connected to the electromagnetic tripping circuit. The resistor R34 is a sampling resistor, and the voltage obtained passes through the LB tripping coil. After being stabilized at 3.3V by the voltage regulator diode Z3, it enters the 8th pin of the MCU microcontroller. As a comparison voltage, if the voltage is 0V, it means that the LB tripping coil is broken and damaged.

[0043] Working principle: When the reset button RESET1 is pressed, the load end is powered, and after being rectified by diode D8 and limited by resistor R26, it drives the input end of optocoupler U5. The output end of optocoupler U5 controls the 9th pin of MCU to become a low level, and the working indicator G (green LED) connected to the 3rd pin of MCU is lit;

[0044] When the unbalanced current passing through the L and N lines of the transformer coil exceeds 6MA, the thyristor Q1 cannot be triggered due to the disconnection or short circuit of the transformer coil, the U1 chip is damaged, or the current limiting resistor that provides power to the U1 chip is damaged, and the MCU's 8th pin cannot be converted to a low level, the MCU determines that the circuit fault cannot play a protective role, and the MCU's 5th pin outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light;

[0045] After pressing the reset button RESET1, press the test button TEST2, the ground fault circuit interrupter (GFCI) should trip immediately. If the tripping time exceeds 200MS, the MCU determines that the disconnection timeout has occurred, and the 5th pin of the MCU microcontroller outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light.

[0046] The working indicator light G is a green LED light, and the end-of-life warning light R is a red LED light. The ground fault circuit breaker status indicated by the two indicators can be seen in the table below.

[0047] Table 1: Indicator light status table

[0048]

[0049]

[0050] The ground fault circuit breaker has manual test trip time and automatic monitoring functions. The manual test (TEST) circuit is controlled by the MCU, which detects the trip time and drives the red indicator light to alarm when the trip time exceeds the standard time, prompting replacement in time, but will not trip directly.

[0051] Example 2

[0052] This embodiment further provides the following improved technical solution based on the above embodiment: a resistor R3 is provided between the 14th pin of the MCU and the transistor Q2.

[0053] Resistor R3 is used to limit the current. The high level output by pin 14 of the MCU controls the transistor Q2 to turn on after the current is limited by resistor R3.

[0054] Example 3

[0055] This embodiment further provides the following improved technical solution based on the above embodiment: the ground fault circuit breaker also includes a USB interface adapter circuit.

[0056] The ground fault circuit breaker is integrated with a USB power board. The USB interface of the USB interface adapter circuit has USB-A and Type-C interfaces, which can provide DC5V to charge mobile phones, tablets, digital cameras and other electrical appliances. The USB power board adopts existing general technology and will not be elaborated.

[0057] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A ground fault circuit breaker with automatic monitoring function, characterized in that: include: A ground fault circuit breaker module, comprising a mutual inductor coil L2, a mutual inductor coil L1, a chip U1, a bridge rectifier D1, a switching power supply circuit and an electromagnetic tripping circuit, wherein the mutual inductor coil L2 is connected to the chip U1, the mutual inductor coil L1 is connected to the chip U1, the switching power supply circuit comprises a resistor R2, a resistor R5 and a capacitor C6, and the electromagnetic tripping circuit comprises an LB tripping coil, a diode D10 and a thyristor Q1; An automatic monitoring circuit, comprising an MCU, a zero-crossing detection sampling circuit, a load voltage sampling circuit and a voltage sampling detection circuit, wherein the load voltage sampling circuit is connected to the 9th pin of the MCU, the voltage sampling detection circuit is connected to the 8th pin of the MCU, the load voltage sampling circuit comprises a diode D8, a resistor R26 and an optical coupler U5, and the diode D8 and the resistor R26 are connected in series; An automatic and manual leakage detection circuit, comprising a reset button RESET, a test button TEST, a transistor Q2, a working indicator light G and an end-of-life alarm light R, wherein the 7th pin of the MCU is connected to the reset button RESET, the 6th pin of the MCU is connected to the test button TEST, the transistor Q2 is connected to the 14th pin of the MCU, the collector of the transistor Q2 is connected to a resistor R25, the resistor R25 is connected to the L-polarity live wire end passing through the transformer coil, the 3rd pin of the MCU is connected to the working indicator light G, and the 5th pin of the MCU is connected to the end-of-life alarm light R; When the reset button RESET is pressed, the load end is powered, and after being rectified by diode D8 and limited by resistor R26, it drives the input end of optocoupler U5. The output end of optocoupler U5 controls the 9th pin of MCU to become a low level, and the working indicator G connected to the 3rd pin of MCU is lit; When the unbalanced current passing through the L and N lines of the transformer coil exceeds 6MA, the thyristor Q1 cannot be triggered, and the MCU pin 8 cannot be converted to a low level, the MCU determines that the circuit is faulty and cannot play a protective role. The MCU pin 5 outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light; After pressing the reset button RESET, press the test button TEST. When the tripping time of the ground fault circuit breaker exceeds the set threshold, the MCU determines that the disconnection has timed out, and the 5th pin of the MCU outputs an intermittent voltage. At this time, the end-of-life alarm light R shows a flashing red alarm light.

2. A ground fault circuit breaker with automatic monitoring function according to claim 1, characterized in that: A resistor R3 is provided between the 14th pin of the MCU and the transistor Q2.

3. A ground fault circuit breaker with automatic monitoring function according to claim 1, characterized in that: The zero-crossing detection sampling circuit includes a resistor R10 and a voltage stabilizing diode Z1.

4. A ground fault circuit breaker with automatic monitoring function according to claim 1, characterized in that: The voltage sampling detection circuit includes a diode D9, a resistor R34 and a voltage stabilizing diode Z3. The diode D9 and the resistor R34 are connected in parallel and then connected to an electromagnetic tripping circuit.

5. A ground fault circuit breaker with automatic monitoring function according to claim 1, characterized in that: The ground fault circuit breaker also includes a USB interface adapter circuit.

Images