An electrical leakage circuit breaker actuation control circuit

Abstract

The application discloses a leakage circuit breaker starting control circuit and relates to the technical field of leakage circuit breakers, which comprises an NMOS tube and a patch capacitor; the output end of an upper power system is connected with the gate and the drain of the NMOS tube, the gate of the NMOS tube is grounded, and the source of the NMOS tube is connected with one end of the patch capacitor; one end of the patch capacitor is connected with an auxiliary power supply circuit and a leakage circuit breaker respectively; the other end of the patch capacitor is grounded; when the auxiliary power supply circuit is not started, the upper power system provides a high level for the gate of the NMOS tube, the NMOS tube is turned on, and the leakage protector is powered after energy storage of the patch capacitor; when the auxiliary power supply circuit has been started, the auxiliary power supply circuit powers the patch capacitor, the source of the NMOS tube is high level after energy storage of the patch capacitor, the NMOS tube is cut off, and the upper power system stops powering the leakage protector. The application effectively improves the power supply reliability of the leakage circuit breaker and realizes the continuous and reliable operation of the system.

Description

Technical Field

[0001] This invention relates to the field of residual current circuit breaker technology, and in particular to a residual current circuit breaker start-up control circuit. Background Technology

[0002] With the continuous improvement and development of people's living standards and electrical technology, electric energy has been applied to all aspects of social development, resulting in the widespread use of electrical equipment. In today's world of mass production and widespread use of electrical equipment, accidents such as electrical leakage and fires caused by improper use, equipment aging, or short circuits are unavoidable. Electrical leakage accidents can range from causing equipment to stop operating to damaging electrical equipment, causing fires, and even endangering the lives of electrical workers.

[0003] A residual current circuit breaker (RCCB) is a switch that automatically disconnects a circuit to prevent fires caused by electrical leakage, prevent electric shock, and protect personal safety and property. When the leakage current in a circuit exceeds a predetermined threshold, the RCCB detects the leakage, triggers its tripping protection mechanism, and disconnects the leakage circuit, thus providing protection. To ensure personal and property safety, RCCBs installed in household and similar applications must possess high reliability and rapid response capabilities. The activation speed of the leakage protection function is a crucial indicator of its effectiveness.

[0004] The residual current circuit breaker (RCCB) protection function requires an auxiliary power supply circuit. This circuit converts the mains power into a stable low-voltage DC voltage, continuously powering the subsequent protection modules and circuits within the RCCB. Generally, power distribution networks consist of different hierarchical topologies. When the upstream power system is operating normally, the auxiliary power supply circuit provides normal power to the RCCB, allowing the downstream circuits within the RCCB to continue operating. If a leakage current fault occurs, the RCCB can operate normally, using the controller to drive the motor to trip and achieve its protection function. Therefore, the normal operation of a RCCB depends on a stable power supply from the auxiliary power supply circuit.

[0005] Currently, most residual current circuit breakers (RCCBs) only assume that the auxiliary power supply circuit is normal and no fault has occurred, neglecting the condition that the RCCB protection mechanism needs to restart after the auxiliary power circuit loses power. This results in significant limitations in the reliability and real-time performance of RCCB protection. When the upstream power system is in a power outage state, the RCCB function is in a dormant state due to the power loss. If there are problems such as insulation damage or aging in the line, and a person or equipment casing accidentally comes into contact with the live wire, a leakage circuit will be formed when the upstream power system suddenly restores power. The existing RCCB mechanism, which relies on the auxiliary power supply circuit, has a slow start-up speed, requiring a long time to start, generally 1-2 seconds, far exceeding the national standard of tripping within 40 milliseconds, seriously endangering personal and property safety. Summary of the Invention

[0006] The purpose of this invention is to provide a starting control circuit for a residual current circuit breaker.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] A leakage current circuit breaker start-up control circuit includes: an NMOS transistor and a surface mount capacitor;

[0009] The output terminal of the upper-level power system is connected to the gate and drain of the NMOS transistor, the gate of the NMOS transistor is grounded, and the source of the NMOS transistor is connected to one end of the surface-mount capacitor.

[0010] One end of the surface mount capacitor is connected to the auxiliary power supply circuit and the leakage current circuit breaker respectively; the other end of the surface mount capacitor is grounded.

[0011] When the auxiliary power supply circuit is not started, the upper-level power system provides a high level to the gate of the NMOS transistor, the NMOS transistor is turned on, and the energy stored in the surface mount capacitor supplies power to the leakage current protector.

[0012] When the auxiliary power supply circuit is started, it supplies power to the surface-mount capacitor. After the surface-mount capacitor stores energy, the source of the NMOS transistor is at a high level, the NMOS transistor is turned off, and the upstream power system stops supplying power to the leakage current protector.

[0013] Optionally, the leakage current circuit breaker start-up control circuit also includes: an NMOS transistor gate bias resistor;

[0014] One end of the gate bias resistor of the NMOS transistor is connected to the output terminal of the upstream power system, and the other end of the gate bias resistor of the NMOS transistor is connected to the gate of the NMOS transistor.

[0015] Optionally, the residual current circuit breaker starting control circuit also includes: a Zener diode;

[0016] One end of the Zener diode is connected to the gate of the NMOS transistor; the other end of the Zener diode is grounded.

[0017] Optionally, the residual current circuit breaker starting control circuit also includes: a current-limiting resistor;

[0018] One end of the current-limiting resistor is connected to the output terminal of the upstream power system, and the other end of the current-limiting resistor is connected to one end of the gate bias resistor of the NMOS transistor.

[0019] Optionally, the residual current circuit breaker starting control circuit also includes: a Schottky diode;

[0020] One end of the Schottky diode is connected to the auxiliary power supply circuit, and the other end of the Schottky diode is connected to one end of the surface-mount capacitor.

[0021] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0022] This invention discloses a residual current circuit breaker (RCCB) start-up control circuit. When the auxiliary power supply circuit is not started, the upstream power system provides a high level to the gate of an NMOS transistor, turning the NMOS transistor on. After energy storage by a surface-mount capacitor, the NMOS transistor supplies power to the RCCB. When the auxiliary power supply circuit is started, it supplies power to the surface-mount capacitor. After energy storage by the surface-mount capacitor, the source of the NMOS transistor becomes high, turning the NMOS transistor off, and the upstream power system stops supplying power to the RCCB. By setting up an RCCB start-up control circuit, this invention enables the auxiliary power supply circuit and the upstream power system to supply power to the RCCB in a coordinated manner, effectively improving the power supply reliability of the RCCB. The RCCB start-up control circuit achieves automatic switching, reducing power loss during system operation while ensuring stable and reliable power supply, thus achieving continuous and reliable system operation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A circuit diagram for starting control of a residual current circuit breaker provided in an embodiment of the present invention;

[0025] Figure 2 A circuit diagram of the power supply control system in which the leakage current circuit breaker start control circuit is located, provided in an embodiment of the present invention;

[0026] Figure 3 A diagram showing the startup time of a traditional residual current circuit breaker system;

[0027] Figure 4 The diagram shows the startup time of the power supply control system where the leakage current circuit breaker startup control circuit is located, as provided in an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The purpose of this invention is to provide a residual current circuit breaker (RCCB) start-up control circuit, which aims to achieve continuous and reliable operation of the RCCB system and can be applied to the field of RCCB technology.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 This is a circuit diagram for starting control of a residual current circuit breaker provided in an embodiment of the present invention. Figure 1 The leakage circuit breaker start-up control circuit in this embodiment includes: an NMOS transistor Q1 and a surface-mount capacitor C1.

[0032] The output terminal of the upstream power system (i.e., DC power supply) is connected to the gate and drain of NMOS transistor Q1. The gate of NMOS transistor Q1 is grounded, and the source of NMOS transistor Q1 is connected to one end of surface-mount capacitor C1.

[0033] One end of the surface mount capacitor C1 is connected to the auxiliary power supply circuit (i.e., auxiliary power supply) and the residual current circuit breaker; the other end of the surface mount capacitor C1 is grounded.

[0034] When the auxiliary power supply circuit (i.e., auxiliary power supply) is not started, the upstream power system (i.e. DC power supply) provides a high level to the gate of NMOS transistor Q1, and NMOS transistor Q1 is turned on. After energy is stored in the chip capacitor C1, it supplies power to the leakage current protector, and the power supply for the protection circuit is established within 10 milliseconds.

[0035] When the auxiliary power supply circuit (i.e., auxiliary power supply) is started, the auxiliary power supply circuit (i.e., auxiliary power supply) supplies power to the surface-mount capacitor C1. After the surface-mount capacitor C1 stores energy, the source of the NMOS transistor Q1 is at a high level, the NMOS transistor Q1 is turned off, and the upstream power system (i.e., DC power supply) stops supplying power to the leakage current protector.

[0036] As an optional implementation, the leakage current circuit breaker start-up control circuit also includes: NMOS transistor gate bias resistor R2.

[0037] One end of the gate bias resistor R2 of the NMOS transistor is connected to the output terminal of the upstream power system (i.e., DC power supply), and the other end of the gate bias resistor R2 is connected to the gate of the NMOS transistor Q1. Specifically, the gate bias resistor R2 provides the operating current for the NMOS transistor Q1.

[0038] As an optional implementation, the leakage current circuit breaker start-up control circuit also includes: Zener diode D2.

[0039] One end of Zener diode D2 is connected to the gate of NMOS transistor Q1; the other end of Zener diode D2 is grounded. Specifically, Zener diode D2 stabilizes the gate voltage of NMOS transistor Q1 at 12V.

[0040] As an optional implementation, the residual current circuit breaker start-up control circuit further includes: a current-limiting resistor R1;

[0041] One end of the current-limiting resistor R1 is connected to the output terminal of the upstream power system (i.e., DC power supply), and the other end of the current-limiting resistor R1 is connected to one end of the gate bias resistor R2 of the NMOS transistor.

[0042] As an optional implementation, the residual current circuit breaker start-up control circuit also includes a Schottky diode D1.

[0043] One end of the Schottky diode D1 is connected to the auxiliary power supply circuit (i.e., the auxiliary power supply), and the other end of the Schottky diode D1 is connected to one end of the surface-mount capacitor C1. Specifically, the Schottky diode D1 prevents the current supplied by the NMOS transistor Q1 from flowing in reverse to the auxiliary power supply circuit. Specific implementation examples:

[0045] Figure 2 This is a circuit diagram of the power supply control system in which the leakage current circuit breaker start-up control circuit is located, as provided in an embodiment of the present invention. Figure 2 As shown, the power supply control system consists of an auxiliary power supply circuit, a residual current circuit breaker (RCCB) start-up control circuit, and a voltage regulator circuit. AC power transmitted from the upstream power system via L (live wire) and N (neutral wire) is converted to DC power by a rectifier circuit. This DC power is then converted to a stable DC power by the auxiliary power supply circuit and the RCCB start-up control circuit. When the auxiliary power supply circuit is not yet activated, the RCCB start-up control circuit supplies power to the subsequent circuits. When the auxiliary power supply circuit is operating normally, the power supply switches from the RCCB start-up control circuit to the auxiliary power supply circuit, and the RCCB start-up control circuit ceases operation. Finally, the voltage regulator circuit converts the voltage to a stable operating voltage for the subsequent circuits.

[0046] The auxiliary power supply circuit is a flyback switching power supply, including Schottky diodes D4, D5, D7, and D8, supercapacitors CE1, CE2, and CE3, capacitor C4, Y capacitor C7, transformer T1, primary-side constant current / constant voltage DC control chip U2, and resistors R4, R6, R8, R10, R11, and R12. Supercapacitor CE1 bypasses and filters out the high-frequency components in the AC signal, which is mixed with high-frequency and low-frequency currents. Supercapacitors CE2 and CE3, and capacitor C4 are used for energy storage in their respective circuits. The auxiliary power supply circuit uses primary-side constant current / constant voltage DC control chip U2, which integrates an NMOS transistor. By controlling the high-frequency switching of this integrated MOS transistor, it drives transformer T1 to transfer energy to the load, achieving voltage conversion. Pin 1 of chip U2 is the power supply voltage pin. When the chip is not working, it is powered by the voltage and current flowing through resistor R6. After the chip is working normally, it is powered by the auxiliary windings 3 and 4 of transformer T1 through Schottky diode D7. Pin 2 is the ground pin, connected to the circuit ground. Pin 3 is the voltage feedback pin. The voltage of the voltage divider circuit formed by resistors R8, R10, and R11 is sent to pin 3 and compared with the internal reference voltage of 2.5V of chip U2 through a comparator formed by the internal operational amplifier. This is used to adjust the pulse duty cycle drive signal generated by chip U2 itself to stabilize the output voltage of the secondary windings 7 and 8 and 5 and 6 of transformer T1. Pin 4 is the current sampling pin, which samples the primary current information to realize current protection. Pins 5, 6, 7, and 8 are the drains of MOSFETs, which are directly connected to the two terminals of the main windings 1 and 2 of transformer T1 to form a complete current loop. When the NMOS transistor Q1 receives a pulse duty cycle drive signal, it turns on and off. When the MOS transistor is on, the rectified DC current flows through the primary windings 1 and 2 of transformer T1, where energy is continuously stored. When the NMOS transistor Q1 is off, transformer T1 transfers the inductance stored in the primary windings 1 and 2 to the secondary windings 7 and 8, and 5 and 6, ultimately stabilizing the output voltage. R4, C3, and D4 form a spike absorption circuit to suppress the reverse high-pulse voltage induced in the primary winding of transformer T1.

[0047] The leakage current circuit breaker (RCCB) start-up control circuit includes an N-channel enhancement-mode NMOS transistor Q1, a Schottky diode D1, a Zener diode D2, a surface-mount capacitor C1, and resistors R1 and R2. When the switching power supply is not started, the AC power supplied by the upstream power system is rectified by diode D3 and then passes through current-limiting resistor R1 (limiting the current flowing out of the rectifier circuit to prevent excessive current from damaging the NMOS transistor Q1). This current then supplies operating current to the Zener diode D2 through the NMOS transistor's gate bias resistor R2, stabilizing the MOS transistor's gate voltage at 12V. At this time, the source (S) voltage of the NMOS transistor Q1 is less than its gate (G) voltage. GS Greater than V GSWhen NMOS transistor Q1 is turned on, energy is stored in capacitor C1 and the DC voltage is stabilized before being supplied to the system through the voltage regulator circuit. This enables the system to power on and operate. When the auxiliary power supply is operating normally, it takes over the system power supply. At this time, its supply current flows into C1, and C1 stores energy, causing the source voltage of NMOS transistor Q1 to rise to 12V, while the gate voltage remains unchanged. GS Less than V GS (th) When the NMOS is turned off, the power supply stops, and the circuit ceases to function.

[0048] The voltage regulator circuit includes a linear regulator U1 and a capacitor C2. The linear regulator U1 converts the 12V voltage provided by the upstream power supply circuit into 3.3V to power the working circuit of the residual current circuit breaker.

[0049] The implementation method is as follows: When the auxiliary power supply circuit is not working properly, the AC power transmitted from the upstream power system is rectified and converted into a small current through a high-resistance bias resistor, so that the Zener diode D2 lowers the gate voltage V of the NMOS transistor Q1. G The voltage is raised to a relatively stable 12V, at which point the source voltage V of NMOS transistor Q1 is... S Its gate-source voltage V is 0. GS Greater than its starting voltage V GS When (th) is reached, NMOS transistor Q1 is turned on, and the leakage circuit breaker starts the control circuit to supply power to the voltage conversion module; when the source voltage V of NMOS transistor Q1 is reached... S When the voltage rises to nearly 12V due to the energy storage capacitor, its gate-source voltage V GS Less than its starting voltage V GS When (th) is reached, NMOS transistor Q1 is turned off, and the leakage circuit breaker start control circuit stops supplying power to the voltage regulator circuit.

[0050] Figure 3 A diagram showing the startup time of a traditional residual current circuit breaker system; Figure 4 This is a startup time diagram of the power supply control system where the leakage current circuit breaker startup control circuit is located, as provided in an embodiment of the present invention. Figure 3 and 4 As shown, when the auxiliary power supply circuit restarts, the startup time of a traditional residual current circuit breaker (RCCB) system is 103.36 ms, which is much longer than the normal tripping time of an RCCB and clearly does not meet the requirements. However, the power supply control system containing the RCCB startup control circuit proposed in this invention responds after 2.32 ms, establishing the protection circuit power supply within 10 milliseconds, enabling the RCCB to trip within 40 ms. Therefore, this invention achieves rapid startup of the RCCB, improving the safety and reliability of electricity use.

[0051] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0052] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the device and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A residual current circuit breaker starting control circuit, characterized in that, include: NMOS transistors and surface-mount capacitors; The output terminal of the upper-level power system is connected to the gate and drain of the NMOS transistor, the gate of the NMOS transistor is grounded, and the source of the NMOS transistor is connected to one end of the surface-mount capacitor. One end of the surface mount capacitor is connected to the auxiliary power supply circuit and the leakage current circuit breaker respectively; the other end of the surface mount capacitor is grounded. When the auxiliary power supply circuit is not started, the upper-level power system provides a high level to the gate of the NMOS transistor, the NMOS transistor is turned on, and the energy stored in the surface mount capacitor supplies power to the leakage current protector. When the auxiliary power supply circuit is started, the auxiliary power supply circuit supplies power to the surface mount capacitor. After the surface mount capacitor stores energy, the source of the NMOS transistor is at a high level, the NMOS transistor is turned off, and the upstream power system stops supplying power to the leakage current protector. The leakage current circuit breaker start-up control circuit also includes: an NMOS transistor gate bias resistor; One end of the gate bias resistor of the NMOS transistor is connected to the output terminal of the upstream power system, and the other end of the gate bias resistor of the NMOS transistor is connected to the gate of the NMOS transistor. The leakage current circuit breaker start-up control circuit also includes: a Zener diode; One end of the Zener diode is connected to the gate of the NMOS transistor; the other end of the Zener diode is grounded. The leakage current circuit breaker start control circuit also includes: a current limiting resistor; One end of the current-limiting resistor is connected to the output terminal of the upstream power system, and the other end of the current-limiting resistor is connected to one end of the gate bias resistor of the NMOS transistor. The leakage current circuit breaker start-up control circuit also includes: a Schottky diode; One end of the Schottky diode is connected to the auxiliary power supply circuit, and the other end of the Schottky diode is connected to one end of the surface mount capacitor.

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