Electric leakage digital detection and rapid protection method and circuit breaker

Abstract

The invention relates to the field of electronic devices, and discloses an electric leakage digital detection and rapid protection method and a circuit breaker, the circuit breaker comprises an electric leakage detection circuit, a power supply rapid starting circuit, a power supply circuit and a circuit break driving circuit, and the method specifically comprises the following steps: in the power-off and power-on stage of a power grid; the power supply output by the power supply quick start circuit is directly obtained, and when the received power supply output by the power supply circuit reaches a preset voltage value, the power supply output by the power supply quick start circuit is stopped; after the power grid is powered on, receiving a power supply output by the power supply circuit; and obtaining a leakage current detection signal output by the electric leakage detection circuit after detecting the load voltage, and outputting a disconnection signal to the disconnection driving circuit when determining that the leakage current of the load is greater than or equal to a preset current value, so that the disconnection driving circuit drives the power-off device to disconnect the circuit. According to the invention, the problem that the time for protecting and disconnecting the load power supply exceeds 40ms when the circuit breaker adopts an MCU chip to digitally detect the leakage current is solved.

Description

Technical Field

[0001] The present invention relates to the field of electronic devices, and in particular to a leakage digital detection and rapid protection method and a circuit breaker. Background Art

[0002] Circuit breakers are crucial protective devices used in power systems, primarily designed to automatically disconnect circuits to prevent damage to electrical equipment and wiring caused by faults such as overloads and short circuits. To ensure the safe and stable operation of power systems, protect electrical equipment, and ensure personnel safety, air circuit breakers must maintain a leakage trip time of less than 40ms.

[0003] Traditional circuit breakers use a mechanical structure to detect power outages, requiring manual adjustment of the circuit board resistance parameters within the factory to adjust the leakage threshold. After leaving the factory, the leakage threshold cannot be adjusted on-site, and there is no way to know whether the specific cause of the circuit breaker tripping was a short circuit or leakage, nor is it possible to record the circuit parameter data when the circuit breaker is operating. When using an MCU chip to record leakage and other circuit parameter data of the circuit breaker, due to the time required for the MCU chip to be powered on and started and the time required for the MCU chip to perform operational detection, the traditional processing method will cause the circuit breaker to take more than 40ms from power-on to leakage detection and tripping, resulting in electrical safety hazards to the load behind the circuit breaker. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a digital leakage detection and rapid protection method and a circuit breaker to solve the problem that when the circuit breaker uses an MCU chip to digitally detect leakage current, the time required to protect and disconnect the load power supply exceeds 40ms.

[0005] The technical solutions of the present invention are as follows: A digital leakage detection and rapid protection method is applied to a circuit breaker. The circuit breaker includes a leakage detection circuit, a power supply rapid start circuit, a power supply circuit, and a circuit breaker drive circuit. The digital leakage detection and rapid protection method specifically includes the following steps: During the power outage to power-on phase, the power supply outputted by the power supply quick start circuit is directly obtained, and when the power supply outputted by the power supply circuit reaches a preset voltage value, the power supply outputted by the power supply quick start circuit is stopped; After the grid is powered on, the power supply is received from the power supply circuit; Obtaining a leakage current detection signal output by a leakage detection circuit after detecting a load voltage; When it is determined according to the leakage current detection signal that the leakage current of the load is greater than or equal to the preset current value, a circuit breaker signal is output to the circuit breaker drive circuit so that the circuit breaker drive circuit drives the power-off device to disconnect the power supply to the load.

[0006] Optionally, when executing the step of obtaining a leakage current detection signal output by the leakage detection circuit after detecting the load voltage, the step further includes: Record the load leakage current data and leakage action waveform.

[0007] Optionally, the leakage digital detection and rapid protection method further includes the following steps: When it is determined according to the leakage current detection signal that the leakage current of the load is less than the preset current value, the power supply control signal is received, the power supply of the power grid to the load is adjusted, and the leakage current value of the load is detected and recorded at the same time.

[0008] Optionally, the power supply circuit is a half-wave rectifier power supply circuit or a full-wave rectifier power supply circuit.

[0009] Optionally, the method further includes the following steps: Receive a leakage threshold adjustment signal, and adjust the preset current value according to the leakage threshold adjustment signal.

[0010] The present invention also proposes a circuit breaker based on the above-mentioned digital leakage detection and rapid protection method, comprising: a leakage detection circuit, wherein a detection terminal of the leakage detection circuit is used to connect to a load, and the leakage detection circuit is used to detect leakage current of the load and output a leakage detection signal; An MCU control chip, wherein the input end of the MCU control chip is connected to the output end of the leakage detection circuit, and the MCU control chip is used to output a circuit breaker signal to the circuit breaker drive circuit when it is determined that the leakage current of the load is greater than or equal to a preset current value according to the leakage detection signal; the MCU control chip is also used to record the leakage current parameter; A power supply quick start circuit, wherein the input end of the power supply quick start circuit is used to connect to the power grid, the output end of the power supply quick start circuit is connected to the power supply end of the MCU control chip, and the power supply quick start circuit is used to directly output power to the MCU control chip when the power grid is powered on; A circuit breaker drive circuit, wherein the input end of the circuit breaker drive circuit is connected to the output end of the MCU control chip, the output end of the circuit breaker drive circuit is used to connect a power-off device, and the circuit breaker drive circuit is used to drive the power-off device to disconnect the load power supply when a circuit breaker signal is received.

[0011] Optionally, the circuit breaker further includes: A power supply circuit, wherein the input end of the power supply circuit is used to connect to the power grid, and the output end of the power supply circuit is connected to the power supply end of the MCU control chip. The power supply circuit is used to convert the output power of the power grid and output it to the MCU control chip. When the power output by the power supply circuit reaches a preset voltage value, the MCU control chip stops receiving the power output by the power quick start circuit.

[0012] Optionally, the power supply quick start circuit includes a first MOS tube, a first resistor, a second resistor, a first diode, a second diode and a third diode; The drain of the first MOS transistor is used to connect to a first power supply, the source of the first MOS transistor is connected to the first end of the first resistor, the second end of the first resistor, the cathode of the first diode, the cathode of the second diode, and the first end of the second resistor are interconnected, and connected to the power supply end of the MCU control chip, the anode of the second diode is used to connect to a second power supply, the second end of the second resistor, the cathode of the third diode, and the gate of the first MOS transistor are interconnected, and the anode of the first diode and the anode of the third diode are grounded.

[0013] Optionally, the power supply quick start circuit includes a second MOS tube, a third resistor, a fourth resistor, a fourth diode and a fifth diode; The drain of the second MOS tube is used to connect to the third power supply, the source of the second MOS tube is connected to the first end of the third resistor, the second end of the third resistor, the first end of the fourth resistor and the cathode of the fourth diode are interconnected, and connected to the power supply end of the MCU control chip, the anode of the fourth diode is used to connect to the fourth power supply, the gate of the second MOS tube, the second end of the fourth resistor and the cathode of the fifth diode are interconnected, and the anode of the fifth diode is grounded.

[0014] Optionally, the power fast start-up circuit includes a third MOS tube, a fifth resistor, a sixth resistor, a sixth diode, a first capacitor, a second capacitor, a first comparator and a first voltage regulator; The drain of the third MOS transistor is used to connect to the fifth power supply, the gate of the third MOS transistor, the first end of the fifth resistor and the output end of the first comparator are interconnected, the second end of the fifth resistor is connected to the power supply end of the MCU control chip, the source of the third MOS transistor is connected to the first end of the sixth resistor, the second end of the sixth resistor, the cathode of the sixth diode, the first end of the first capacitor and the input end of the first voltage regulator are interconnected, the anode of the sixth diode is used to connect to the sixth power supply, the output end of the first voltage regulator is connected to the first end of the second capacitor and to the power supply end of the MCU control chip, the first input end of the first comparator is connected to the power supply end of the MCU control chip, the second output end of the first comparator is used to connect to the sixth power supply, the second end of the first capacitor, the ground end of the first voltage regulator and the second end of the second capacitor are grounded.

[0015] The present invention utilizes a circuit breaker with a digital leakage detection and rapid protection method. When using an MCU control chip, the circuit breaker uses a rapid power startup circuit to immediately power the MCU control chip upon grid power-up, enabling the MCU to operate immediately and driving a power-off device to disconnect the circuit when the load leakage current is high. Furthermore, the rapid power startup circuit and the power supply circuit supply power to the MCU control chip at different power-up time intervals. This allows the circuit breaker to disconnect the circuit in less than 40 milliseconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary personnel in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0017] Figure 1 It is a schematic diagram of the method steps of an embodiment of the leakage digital detection and rapid protection method of the present invention.

[0018] Figure 2 It is a schematic diagram of the method steps of another embodiment of the leakage digital detection and rapid protection method of the present invention.

[0019] Figure 3 This is a schematic diagram of the method steps of another embodiment of the leakage digital detection and rapid protection method of the present invention.

[0020] Figure 4 This is a schematic diagram of the method steps of another embodiment of the leakage digital detection and rapid protection method of the present invention.

[0021] Figure 5 It is a functional module diagram of an embodiment of a circuit breaker of the present invention.

[0022] Figure 6 The figure is a circuit structure diagram of an embodiment of a power supply rapid starting circuit in a circuit breaker of the present invention.

[0023] Figure 7 It is a circuit structure diagram of another embodiment of the power supply quick start circuit in the circuit breaker of the present invention.

[0024] Figure 8 The figure is a circuit structure diagram of another embodiment of the power supply quick starting circuit in the circuit breaker of the present invention.

[0025] Figure 9 The figure is a circuit structure diagram of an embodiment of a leakage detection circuit in a circuit breaker of the present invention.

[0026] Figure 10 1 is a circuit structure diagram of an embodiment of a circuit breaker driving circuit in the present invention.

[0027] Explanation of the accompanying symbols: 10, power supply fast start circuit; 21, leakage detection circuit; 22, MCU control chip; 30, circuit breaker drive circuit; 40, power supply circuit; L, power grid; V1, first power supply; V2, second power supply; V3, third power supply; V4, fourth power supply; V5, fifth power supply; V6, sixth power supply; V7, seventh power supply; J1, electrical interface; J2, power-off device socket; U1, first voltage regulator; U2, first comparator; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; R10, tenth resistor; R11, eleventh resistor The first resistor is R12, the twelfth resistor; the second resistor is R13, the thirteenth resistor; the fourth resistor is R14; the first capacitor is C1; the second capacitor is C2; the third capacitor is C3; the fourth capacitor is C4; the fifth capacitor is C5; the first MOS transistor is Q1; the second MOS transistor is Q2; the third MOS transistor is Q3; the fourth MOS transistor is Q4; the first triode is Q5; the first diode is D1; the second diode is D2; the third diode is D3; the fourth diode is D4; the fifth diode is D5; the sixth diode is D6; the sixth diode is D7; the seventh diode is D8; the eighth diode is D9; the ninth diode is D10; the tenth diode is D11; the eleventh diode is D12; the twelfth diode is D13; the first thyristor is SCR. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] In the embodiments and patent claims, unless otherwise specified herein, the words "a," "an," "the," and "the" may include plural forms. If the embodiments of the present invention include descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features.

[0030] It should be further understood that the term "comprising" as used in the description of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when an element is said to be "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intermediate elements. In addition, "connected" or "coupled" as used herein can include wireless connections or wireless couplings. The term "and / or" as used herein includes all or any units and all combinations of one or more associated listed items.

[0031] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0032] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0033] Circuit breakers are crucial protective devices used in power systems, primarily designed to automatically disconnect circuits to prevent damage to electrical equipment and wiring caused by faults such as overloads and short circuits. To ensure the safe and stable operation of power systems, protect electrical equipment, and ensure personnel safety, air circuit breakers must maintain a leakage trip time of less than 40ms.

[0034] Traditional circuit breakers use a mechanical structure to detect power outages, requiring manual adjustment of the leakage threshold. Furthermore, it is impossible to determine whether the circuit breaker tripped due to a short circuit or leakage, and it is impossible to record the circuit parameter data during the circuit breaker operation. When using an MCU chip to record leakage and other circuit parameter data of the circuit breaker, the time it takes for the MCU chip to be powered on and start up, and the time it takes for the MCU chip to perform operational detection, will cause the time from grid power-on to leakage tripping to exceed 40ms, posing a safety hazard to the circuit breaker.

[0035] To solve the above problems, the present invention proposes a digital leakage detection and rapid protection method, which is applied to a circuit breaker. The circuit breaker includes a leakage detection circuit, a power rapid start circuit, a power circuit and a circuit breaker drive circuit.

[0036] Reference Figure 1 In one embodiment, the leakage current digital detection and rapid protection method specifically includes the following steps: S100, during a power outage to power-on phase of the power grid, directly obtaining power outputted by the power supply quick start circuit and stopping obtaining power outputted by the power supply quick start circuit when the power outputted by the power supply circuit reaches a preset voltage value; S110, receiving power output by the power circuit after the grid is powered on; S200, obtaining a leakage current detection signal output by the leakage detection circuit after detecting the load voltage; S300 , when it is determined according to the leakage current detection signal that the leakage current of the load is greater than or equal to the preset current value, outputting a disconnection signal to the disconnection drive circuit so that the disconnection drive circuit drives the power-off device to disconnect the power supply to the load.

[0037] In this embodiment, after the grid is powered on, a leakage current detection circuit detects the leakage current of the load and outputs an analog signal, namely, a leakage current detection signal. The analog signal is then obtained and converted into a digital signal to determine the magnitude of the leakage current. If the leakage current is greater than or equal to a preset current value, it indicates that the leakage current is large and poses a safety hazard. In this case, a corresponding electrical signal, namely, a circuit breaker signal, is output to the circuit breaker drive circuit. The circuit breaker drive circuit then outputs an electrical signal to a power-off device, causing the power-off device to disconnect the current in the circuit, thereby disconnecting the load power supply. Typically, after the grid is powered on, the power output from the grid is rectified and transformed before outputting a voltage to the MCU control chip for leakage current detection. To ensure that the circuit breaker disconnects the circuit within 40ms when a load leakage occurs after power is applied, this embodiment directly obtains the power output from the power supply quick start circuit. This allows for direct leakage current detection and subsequent control of the load, eliminating the need for prior power supply rectification and transformation steps to obtain power supply. This can shorten the time required for the circuit breaker to disconnect the circuit when a leakage occurs after power is applied. It should be noted that the power supply circuit has high power but slow startup, while the power supply quick start circuit has low power but fast startup. This embodiment combines the advantages of the two power supplies. In different time periods of power-on, the power supply is supplied by the power supply quick start circuit and the power supply circuit respectively, realizing seamless switching of the dual power supplies, which not only ensures fast power supply, but also ensures the normal operation of subsequent circuits. Directly obtaining the power supply from the power grid during the power-on phase from power outage to power-on can directly perform leakage current detection and subsequent control on the load without the need for pre-processing power rectification, transformer conversion and other steps to obtain power supply. This can shorten the time required for the circuit breaker to disconnect the circuit when leakage occurs during the power-on phase. After the power grid is powered on normally, the power supply circuit is used for power supply. In this way, the function of full-time leakage detection and protection can be realized.

[0038] The present invention utilizes a circuit breaker with a digital leakage detection and rapid protection method. When using an MCU control chip, the circuit breaker uses a rapid power startup circuit to immediately power the MCU control chip upon grid power-up, enabling the MCU to operate immediately. Furthermore, the circuit breaker activates a power-off device to disconnect the circuit when the load leakage current is high. This reduces the time it takes to disconnect the load power supply to less than 40 milliseconds.

[0039] Reference Figure 2 In one embodiment, when executing the step of obtaining the leakage current detection signal output by the leakage detection circuit after detecting the load voltage, the step further includes: S210 , recording the leakage current data of the load and the waveform of the leakage action.

[0040] In this embodiment, recording the leakage current parameters and other circuit parameters of the load during the operation of the circuit breaker, such as the waveform of the leakage action, can facilitate viewing by users or maintenance personnel or realize the safety early warning function.

[0041] Reference Figure 3 In one embodiment, the leakage current digital detection and rapid protection method further includes the following steps: S400 , when it is determined according to the leakage current detection signal that the leakage current of the load is less than the preset current value, a power supply control signal is received, power supply of the power grid to the load is adjusted, and the leakage current value of the load is detected and recorded.

[0042] In this embodiment, when the load leakage current is less than a preset current value, indicating that the leakage current is small and there is no safety hazard, a power supply control signal can be received to adjust the power supply from the power grid to the load. The power supply control signal can be output manually or via a remote control terminal. Simultaneously, the load leakage current value is detected and recorded, providing users with real-time leakage current monitoring data.

[0043] In one embodiment, the power supply circuit is a half-wave rectifier power supply circuit or a full-wave rectifier power supply circuit.

[0044] In this embodiment, the power supply circuit can use half-wave rectification, which will result in no voltage for half a cycle; full-wave rectification can also be used, but full-wave rectification requires an isolated power supply, which will increase the size of the circuit breaker; the specific use of half-wave rectification power supply circuit or full-wave rectification power supply circuit can be selected according to actual conditions and user needs.

[0045] Reference Figure 4 In one embodiment, the leakage current digital detection and rapid protection method further includes the following steps: S500: Receive a leakage threshold adjustment signal, and adjust a preset current value according to the leakage threshold adjustment signal.

[0046] In this embodiment, the leakage threshold adjustment signal output by an external terminal, such as a mobile phone or Bluetooth device, can be received through the communication function, so that the user can remotely adjust the leakage current threshold or realize the control of other functions.

[0047] Based on the above-mentioned digital leakage detection and rapid protection method, the present invention also provides a circuit breaker.

[0048] Reference Figure 5 In one embodiment, the circuit breaker comprises: A leakage detection circuit 21, wherein a detection terminal of the leakage detection circuit 21 is connected to a load, and the leakage detection circuit 21 is used to detect leakage current of the load and output a leakage detection signal; An MCU control chip 22, wherein the input end of the MCU control chip 22 is connected to the output end of the leakage detection circuit 21, and the MCU control chip 22 is configured to output a circuit breaker signal to the circuit breaker drive circuit when it is determined based on the leakage detection signal that the leakage current of the load is greater than or equal to a preset current value; the MCU control chip 22 is also configured to record leakage current parameters; A power supply quick start circuit 10, wherein the input end of the power supply quick start circuit 10 is used to connect to the power grid L, and the output end of the power supply quick start circuit 10 is connected to the power supply end of the MCU control chip 22. The power supply quick start circuit 10 is used to directly output power to the MCU control chip 22 when the power grid L is powered on; The circuit breaker drive circuit 30 has an input end connected to the output end of the MCU control chip 22, and an output end of the circuit breaker drive circuit 30 is used to connect a power-off device. The circuit breaker drive circuit 30 is used to drive the power-off device to disconnect the load power supply when a circuit breaker signal is received.

[0049] In this embodiment, the leakage detection circuit 21 can be composed of multiple electronic components such as capacitors, diodes, and resistors. It detects the leakage current of the load and outputs an analog signal. The MCU control chip 22 then converts the analog signal into a digital signal to determine the magnitude of the leakage current. When the leakage current is greater than the current value preset in the MCU control chip 22, it indicates that the leakage current is large and there is a safety hazard. In this case, the MCU control chip 22 can output a corresponding electrical signal, namely a circuit breaker signal, to the circuit breaker drive circuit 30. The circuit breaker drive circuit 30 can be composed of multiple capacitors, resistors, and switching devices. The circuit breaker drive circuit 30 can drive the power-off device to turn on and off. The power-off device can be a device such as an electromagnet or a mechanical switch. For example, the electromagnet in a circuit breaker is installed in the circuit and remains in a closed state during normal operation. When the drive circuit receives the circuit breaker signal, it outputs an electrical signal to the electromagnet, causing the electromagnet to disconnect the current in the circuit, thereby disconnecting the circuit. The MCU control chip 22 can be an RN8211B-V3 MCU chip, or other chips with similar functions. The MCU control chip 22 can also record the leakage current parameters and other circuit parameters during the circuit breaker operation, making it easier for users or maintenance personnel to view or implement safety warning functions. The MCU control chip 22 also has a communication function, allowing users to remotely adjust the leakage current threshold or implement other functions.

[0050] It should be noted that, typically, during the power-on phase of the power grid L, the power output from the power grid L is rectified and transformed before the output voltage is supplied to the MCU control chip 22 for power supply. To ensure that the circuit breaker disconnects the circuit within 40 milliseconds in the event of a load leakage after power-on, the circuit breaker of this embodiment also includes a power supply rapid startup circuit 10. The power supply rapid startup circuit 10 can be composed of electronic components such as switching devices, resistors, or capacitors. The power supply rapid startup circuit 10 can connect the power grid L and the power supply terminals of the MCU control chip 22. During the power-on phase of the power grid L, the power supply from the power grid L is directly output to the MCU control chip 22 to supply power to the MCU control chip 22. This allows the MCU control chip 22 to directly detect and subsequently control the load leakage current without requiring prior power supply rectification and transformation steps. This shortens the time required for the circuit breaker to disconnect the circuit in the event of a load leakage after power-on. After the power grid L is powered on normally, the power supply circuit is used to supply power to the MCU control chip 22. This enables full-time leakage detection and protection.

[0051] The circuit breaker of this embodiment, when using an MCU control chip 22, can supply power to the MCU control chip 22 via the power supply rapid startup circuit 10 as soon as the power grid L is powered on. This allows the MCU control chip 22 to immediately perform leakage detection and control, and drive the power-off device to disconnect the circuit when the leakage current is large. This allows the circuit breaker to disconnect the circuit within 40ms.

[0052] Reference Figure 6 In one embodiment, the power supply quick start circuit 10 includes a first MOS transistor Q1, a first resistor R1, a second resistor R2, a first diode D1, a second diode D2 and a third diode D3; The drain of the first MOS transistor Q1 is used to connect to the first power supply V1, the source of the first MOS transistor Q1 is connected to the first end of the first resistor R1, the second end of the first resistor R1, the cathode of the first diode D1, the cathode of the second diode D2, and the first end of the second resistor R2 are interconnected and connected to the power supply end of the MCU control chip 22, the anode of the second diode D2 is used to connect to the second power supply V2, the second end of the second resistor R2, the cathode of the third diode D3, and the gate of the first MOS transistor Q1 are interconnected, and the anode of the first diode D1 and the anode of the third diode D3 are grounded.

[0053] For three-phase AC power, the power supply fast startup circuit 10 of this embodiment can be used for fast startup. The first MOS transistor Q1 can be a depletion-mode PMOS transistor, and the first transistor Q5 and the third transistor can be voltage-stabilizing diodes. When power is first applied, the depletion-mode PMOS transistor is in the on state, and the first power supply V1 can be a power supply from the power grid L. The first power supply V1 is directly output to the power supply terminal of the MCU control chip 22 through the first MOS transistor Q1 and the first resistor R1 to power the MCU control chip 22. At this point, the power supply circuit 40 in the circuit breaker performs steps such as rectification and transformation on the power supply of the power grid L, converting it to a suitable operating voltage and outputting a second power supply V2. This power supply is then output to the power supply terminal of the MCU control chip 22 via the second diode D2. Furthermore, the voltage at the cathode of the third diode D3 increases with the output of the first power supply V1 and the second power supply V2. When the breakdown voltage of the third diode D3 is reached, the third diode D3 conducts in reverse, pulling the gate voltage of the first MOS transistor Q1 down to ground. At this point, the gate-source voltage difference of the first MOS transistor Q1 is less than the conduction voltage, and the first MOS transistor Q1 is turned off. The power supply fast startup circuit 10 stops outputting power to the power supply terminal of the MCU control chip 22, and the third power supply V3 supplies power to the MCU control chip 22. The breakdown voltage of the third diode D3 can be selected based on actual conditions and user needs.

[0054] Reference Figure 7In one embodiment, the power supply quick start circuit 10 includes a second MOS transistor Q2, a third resistor R3, a fourth resistor R4, a fourth diode D4 and a fifth diode D5; The drain of the second MOS transistor Q2 is used to connect to the third power supply V3, the source of the second MOS transistor Q2 is connected to the first end of the third resistor R3, the second end of the third resistor R3, the first end of the fourth resistor R4, and the cathode of the fourth diode D4 are interconnected and connected to the power supply end of the MCU control chip 22, the anode of the fourth diode D4 is used to connect to the fourth power supply V4, the gate of the second MOS transistor Q2, the second end of the fourth resistor R4, and the cathode of the fifth diode D5 are interconnected, and the anode of the fifth diode D5 is grounded.

[0055] For single-phase AC power, the power supply fast startup circuit 10 of this embodiment can be used for fast startup. The second MOS transistor Q2 can be a depletion-mode PMOS transistor, and the fifth diode D5 can be a transient suppression diode. When power is first applied, the depletion-mode PMOS transistor is in the on state, and the third power supply V3 can be a power supply of the power grid L. The third power supply V3 is directly output to the power supply terminal of the MCU control chip 22 through the second MOS transistor Q2 and the third resistor R3 to power the MCU control chip 22. At this time, the power supply circuit 40 in the circuit breaker will perform rectification and transformation on the power supply of the power grid L, convert it into a suitable working voltage, and then output the fourth power supply V4, which is then output to the power supply terminal of the MCU control chip 22 through the fourth diode D4; and the voltage of the cathode of the fifth diode D5 will become higher and higher with the output of the third power supply V3 and the fourth power supply V4. When the breakdown voltage of the fifth diode D5 is reached, the fifth diode D5 will reverse conduct, pulling the gate voltage of the second MOS tube Q2 down to the ground. At this time, the gate-source voltage difference of the second MOS tube Q2 is less than the conduction voltage, the second MOS tube Q2 is turned off, and the power supply fast start-up circuit 10 stops outputting power to the power supply terminal of the MCU control chip 22, and the third power supply V3 supplies power to the MCU control chip 22. The breakdown voltage of the fifth diode D5 can be selected according to actual conditions and user needs. In addition, Figure 7 The N in can represent the zero line.

[0056] Reference Figure 8 In one embodiment, the power supply fast start-up circuit 10 includes a third MOS transistor Q3, a fifth resistor R5, a sixth resistor R6, a sixth diode D6, a first capacitor C1, a second capacitor C2, a first comparator U2 and a first voltage regulator U1; The drain of the third MOS transistor Q3 is used to connect to the fifth power supply V5. The gate of the third MOS transistor Q3, the first end of the fifth resistor R5, and the output end of the first comparator U2 are interconnected. The second end of the fifth resistor R5 is connected to the power supply end of the MCU control chip 22. The source of the third MOS transistor Q3 is connected to the first end of the sixth resistor R6. The second end of the sixth resistor R6, the cathode of the sixth diode D6, the first end of the first capacitor C1, and the input end of the first voltage regulator U1 are interconnected. The anode of the sixth diode D6 is used to connect to the sixth power supply V6. The output end of the first voltage regulator U1 is connected to the first end of the second capacitor C2 and to the power supply end of the MCU control chip 22. The first input end of the first comparator U2 is connected to the power supply end of the MCU control chip 22. The second output end of the first comparator U2 is used to connect to the sixth power supply V6. The second end of the first capacitor C1, the ground end of the first voltage regulator U1, and the second end of the second capacitor C2 are grounded.

[0057] For single-phase AC power, the power supply quick startup circuit 10 of the structure in this embodiment can also be used to quickly start the power supply. When power is first applied, the voltage at the power supply terminal of the MCU control chip 22 is 0, the sixth power supply V6 is also 0, the first comparator U2 is inoperative, and the gate of the third MOS transistor Q3 is connected to the power supply terminal of the MCU control chip 22 via the fifth resistor R5. Therefore, the gate potential is 0, and the voltage of the first capacitor C1 is 0. Therefore, the source potential of the third MOS transistor Q3 is also 0, and the gate-source voltage difference of the third MOS transistor Q3 is 0V, and the third MOS transistor Q3 is turned on.The fifth power supply V5 can be a power supply of the power grid L, and the sixth power supply V6 can be a power supply output by the front-stage power supply circuit 40 after converting the power grid L. The fifth power supply V5 directly charges the first capacitor C1 and supplies power to the rear-end load of the first voltage regulator U1 through the loop of the third MOS tube Q3 and the sixth resistor R6. As the first capacitor C1 and the second capacitor C2 are charged, the voltage of the power supply end of the MCU control chip 22 and the first capacitor C1 gradually rises. Before the power supply end voltage of the MCU control chip 22 rises to the regulated voltage value of 3.3V of the first voltage regulator U1, the gate voltage of the third MOS tube Q3 is equal to the power supply end voltage of the MCU control chip 22, and the source voltage of the third MOS tube Q3 is equal to the MCU control chip 22. The power supply terminal voltage of the chip 22, so the gate-source voltage difference of the third MOS tube Q3 is approximately 0V, and it is always in the on state, and continuously supplies power from the high-voltage fifth power supply V5 to the subsequent stage; after the power supply terminal voltage of the MCU control chip 22 rises to the regulated voltage value of 3.3V of the first voltage regulator U1, the power supply terminal of the MCU control chip 22 remains unchanged at 3.3V, and the voltage of the sixth power supply V6 is lower than the power supply terminal of the MCU control chip 22 because the front-stage power supply circuit 40 starts slowly. The first comparator U2 always outputs a high level, that is, the gate voltage of the third MOS tube Q3 is equal to the power supply terminal voltage of the MCU control chip 22, which is equal to 3.3V, and the voltage of the first capacitor C1 is increased with the fifth power supply V5 through the third MOS tube Q3. The charge of the transistor Q3 continues to increase, resulting in a continuous increase in the source voltage of the third MOS transistor Q3. The gate-source voltage difference of the third MOS transistor Q3 will gradually approach the turn-off threshold, and the conduction capability of the third MOS transistor Q3 will decrease. When the current flowing through the third MOS transistor Q3 and the subsequent load current are equal, a balance is reached. At this time, the voltage of the first capacitor C1 is approximately the turn-off threshold of the third MOS transistor Q3 plus the power supply terminal voltage of the MCU control chip 22. The turn-off threshold of the third MOS transistor Q3 is between -1.5V and -3.3V. Therefore, the voltage of the first capacitor C1 is 3.3+1.5=4.8V to 3.3+3.3=6.6V. If the sixth power supply V6 rises to 5V, the sixth power supply V6 passes through the first capacitor C1. After the voltage regulator U1, the voltage drops to 4.6V, which could prevent the third MOS transistor Q3 from being fully shut down, potentially causing it to burn out from long-term power supply. Therefore, a first comparator U2 is added to assist in shutdown. As long as the voltage of the sixth power supply V6 rises above the power supply voltage of the MCU control chip 22, the first comparator U2 outputs 0V. As long as the source voltage of the third MOS transistor Q3, i.e., the voltage of the first capacitor C1, reaches 3.3V, the third MOS transistor Q3 is shut down. Once the pre-stage power supply circuit 40 is fully operational, the voltage of the first capacitor C1 can be raised to 4.6V, completely shutting down the third MOS transistor Q3, thereby achieving a switch from power supply from the fast power startup circuit 10 to power supply from the grid L. Furthermore, Figure 8 The N in can represent the zero line.

[0058] Further, refer to Figure 9 In one embodiment, the leakage detection circuit 21 includes a seventh diode D7, an eighth diode D8, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a third capacitor C3 and a fourth capacitor C4; The cathode of the seventh diode D7, the anode of the eighth diode D8, the first end of the seventh resistor R7, and the first end of the eighth resistor R8 are interconnected and used to connect the first end of the electrical interface J1. The anode of the seventh diode D7, the cathode of the eighth diode D8, the second end of the seventh resistor R7, and the first end of the ninth resistor R9 are interconnected and used to connect the second end of the electrical interface J1. The second end of the eighth resistor R8 and the first end of the third capacitor C3 are interconnected and connected to the input end of the MCU control chip 22. The second end of the ninth resistor R9 and the first end of the fourth capacitor C4 are interconnected and connected to the input end of the MCU control chip 22. The second end of the third capacitor C3 and the second end of the fourth capacitor C4 are connected and grounded.

[0059] In this embodiment, the electrical interface J1 is used to connect the load, and the seventh diode D7 and the eighth diode D8 can play the role of limiting protection. When the voltage at the first end of the electrical interface J1 is higher than the voltage at the second end and exceeds a certain value, the seventh diode D7 is turned on, limiting the voltage to a safe range; when the voltage at the second end of the electrical interface J1 is higher than the voltage at the first end and exceeds a certain value, the eighth diode D8 is turned on, also limiting the voltage to a safe range, thereby protecting subsequent resistors, capacitors and MCU control chip 22 from damage by high voltage. The seventh resistor R7 can play a current limiting role, the eighth resistor R8 and the ninth resistor R9 can play a voltage dividing role. The third capacitor C3 and the fourth capacitor C4 can play a filtering role. In this way, the leakage detection circuit 21 in this embodiment achieves accurate detection of load leakage through the limiting protection of the diode, the voltage dividing and current limiting of the resistor, and the filtering effect of the capacitor.

[0060] Reference Figure 10 In one embodiment, the disconnection driving circuit 30 includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a ninth diode D9, a tenth diode D10, an eleventh diode D11, a twelfth diode D12, a first thyristor D13, a first transistor Q5, a fourth MOS transistor Q4, and a fifth capacitor C5; The first end of the tenth resistor R10 is connected to the output end of the MCU control chip 22, the second end of the tenth resistor R10 is connected to the anode of the ninth diode D9, the first end of the eleventh resistor R11 is connected to the output end of the MCU control chip 22, the second end of the eleventh resistor R11, the anode of the tenth diode D10 and the drain of the fourth MOS transistor Q4 are interconnected, the gate of the fourth MOS transistor Q4 is connected to the output end of the MCU control chip 22, the source of the fourth MOS transistor Q4 is grounded, the ninth diode D9, the cathode of the tenth diode D10, the base of the first transistor Q5 and the first end of the twelfth resistor R12 are interconnected, the second end of the twelfth resistor R12 is grounded, the collector of the first transistor Q5 and the A first end of the thirteenth resistor R13 is connected, a second end of the thirteenth resistor R13 is connected to the power supply end of the MCU control chip 22, the emitter of the first transistor Q5, the first end of the fourteenth resistor R14, the first end of the fifth capacitor C5 and the gate of the first thyristor D13 are interconnected, the second end of the fourteenth resistor R14, the second end of the fifth capacitor C5 and the cathode of the first thyristor D13 are grounded, the anode of the first thyristor D13 is connected to the cathode of the eleventh diode D11, the anode of the eleventh diode D11 is connected to the anode of the twelfth diode D12, and is used to connect to the first end of the power-off device socket J2, the cathode of the twelfth diode D12 is used to connect to the seventh power supply V7, and is used to connect to the second end of the power-off device socket J2.

[0061] In this embodiment, the tenth resistor R10 and the eleventh resistor R11 can function as current limiters; the twelfth resistor R12 can function as current limiters and voltage dividers to ensure the normal operation of the first transistor Q5; the thirteenth resistor R13 can function as a pull-up resistor, providing power to the collector of the first transistor Q5; and the fourteenth resistor R14 can function as a current limiting resistor, limiting the current flowing into the gate of the first thyristor D13 to prevent excessive gate current from damaging the thyristor. The ninth diode D9 and the tenth diode D10 can function as isolation and rectification. They isolate the signals output by the MCU control chip 22 to prevent mutual signal interference, and at the same time, rectify the high-level signals to provide a forward bias voltage for the base of the first transistor Q5. The eleventh diode D11 and the twelfth diode D12 function as isolation and protection. The eleventh diode D11 prevents reverse current from flowing into the first thyristor D13, while the twelfth diode D12 is used to connect to the seventh power supply V7 to provide a suitable driving voltage for the power-off device and also prevent reverse current flow. The first transistor Q5 acts as an amplifier and switching element. When the base receives a suitable bias voltage, it turns on, amplifying the signal output by the MCU control chip 22 and providing sufficient trigger current for the gate of the first thyristor D13. The first thyristor D13 acts as a switching element. It turns on after receiving a trigger signal at the gate, providing drive current to the power-off device, thereby controlling its operation. Once turned on, it remains on as long as sufficient current is maintained between the anode and cathode, and will not turn off until the anode current falls below the holding current. The fourth MOS transistor Q4 acts as a switching element, controlling the on / off state of the circuit based on the signal output by the MCU control chip 22. When the gate receives a high-level signal, it turns on, providing a path for subsequent circuits; when it receives a low-level signal, it turns off, disconnecting the circuit. The fifth capacitor C5 provides filtering and delay functions. In the gate circuit of the first thyristor D13, the capacitor can filter out high-frequency interference signals, making the trigger signal more stable. Furthermore, the charging and discharging process of the capacitor can provide a certain delay to prevent false triggering. It should be noted that in this embodiment, the first end of the tenth resistor R10 is connected to the output end of the MCU control chip 22 and is used to receive the remote closing and closing command signal output by the MCU control chip 22. That is, the user can control the closing or opening of the power-off device through the MCU control chip 22. The first end of the eleventh resistor R11 is connected to the output end of the MCU control chip 22 and is used to receive the leakage protection trip signal output by the MCU control chip 22. That is, when the MCU control chip 22 detects leakage in the power grid L, it outputs a trip signal to the first end of the eleventh resistor R11, thereby controlling the opening of the power-off device. The gate of the fourth MOS transistor Q4 is used to receive the contact status signal output by the MCU control chip 22, which can prevent the power-off device from being re-closed due to leakage drive when it is open. The seventh power supply V7 can be output by the pre-stage power supply circuit 40.

[0062] Reference Figure 5 In one embodiment, the circuit breaker further comprises: The power supply circuit 40 has an input end for connecting to a power grid, and an output end for connecting to a power supply end of the MCU control chip 22. The power supply circuit 40 is used to convert the output voltage of the power grid and output it to the MCU control chip 22. When the power output by the power supply circuit 40 reaches a preset voltage value, the MCU control chip 22 stops receiving the power output by the power quick start circuit 10.

[0063] In this embodiment, the power circuit 40 can be composed of electronic components such as capacitors, resistors, inductors and diodes. The power circuit 40 can rectify, filter and transform the output voltage of the power grid and then output it to the MCU control chip 22 for normal power supply. The specific circuit structure of the power circuit 40 can be referred to Figure 6 、 Figure 7 and Figure 8 For power supply quick start circuits 10 with different structures, corresponding power supply circuits 40 can be configured to perform power conversion. When the power output from power supply circuit 40 reaches a preset voltage, the MCU control chip 22 stops receiving power from the power supply quick start circuit 10, achieving seamless switching of dual power supplies.

[0064] In one embodiment, the power supply circuit 40 is a half-wave rectifier power supply circuit 40 or a full-wave rectifier power supply circuit 40 .

[0065] In this embodiment, the power supply circuit 40 in the circuit breaker can use half-wave rectification in combination with an MCU chip. Half-wave rectification will result in no voltage for half a cycle; full-wave rectification can also be used, but full-wave rectification requires an isolated power supply, which will increase the size of the circuit breaker; the specific use of half-wave rectification power supply circuit 40 or full-wave rectification power supply circuit 40 can be selected according to actual conditions and user needs.

[0066] In order to better illustrate the technical concept of the present invention, the following Figures 1 to 10 To explain: First, the entire process from the power-on of the power grid L to the detection of load leakage and the triggering of the leakage tripping action of the circuit breaker includes the power-on of the power grid L, the stable power supply to the MCU control chip 22, the MCU control chip 22 performing leakage detection, the triggering of leakage control, and the circuit breaker drive circuit 30 driving the electromagnet to open and trip to extinguish the arc. Among them, it takes a fixed time of 10ms from the stable power supply of the MCU control chip 22 to the MCU control chip 22 performing leakage detection; it takes 3ms to 5ms from leakage detection to triggering leakage control, and it takes 1ms for the circuit breaker drive circuit 30 to drive the electromagnet to open. It should be noted that it takes 1ms to 2ms to power on the power supply quick start circuit 10 of this solution, while it takes 15ms to 20ms to power on through the power supply circuit 40. In the case of half-wave rectification, it takes 0ms to 10ms for the leakage control to be triggered and the circuit breaker drive circuit 30 to drive the electromagnet to open the switch. The arc extinguishing requires crossing the zero point, so it takes 0ms to 10ms. The use of half-wave rectification may also lose 0ms to 10ms of time when powering on.

[0067] The circuit breaker of this solution can control the entire process within 40ms. Taking the grid L frequency of 50 Hz as an example, the period of one AC wavelength is 20ms. In this scheme, the time required from the power-on of the MCU control chip 22 to the triggering of leakage control is fixed at 14ms to 17ms. When half-wave rectification is adopted, 0ms to 10ms is positive current and voltage, 10ms to 20ms is negative current and no voltage, and so on. Assuming that the power grid L is powered on at 10ms and there is no voltage, it takes 20ms for voltage to appear, and 10ms of time has been lost. Then, the time required from the power-on of the MCU control chip 22 to the triggering of leakage control is 17ms. At this time, it is a positive current and voltage. The circuit breaker drive circuit 30 can directly drive the electromagnet to open the gate without losing time. After another 1ms, the circuit breaker drive circuit 30 drives the electromagnet to open the gate. At this time, it is 28ms and a positive current. It crosses the zero point at 30ms to achieve tripping and arc extinguishing. Even if the arc cannot be tripped and extinguished at 30ms due to circuit delay or other reasons, it can be tripped and arc extinguished by crossing the zero point again at 40ms. Therefore, the time from the power supply of the grid L to the detection of load leakage and the triggering of the leakage tripping action of the circuit breaker in this solution will not exceed 40ms.

[0068] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A digital leakage detection and rapid protection method, applied to circuit breakers, characterized in that: The circuit breaker includes a leakage detection circuit, a power supply quick start circuit, a power supply circuit and a circuit breaker drive circuit. The leakage digital detection and quick protection method specifically includes the following steps: During the power outage to power-on phase, the power supply outputted by the power supply quick start circuit is directly obtained, and when the power supply outputted by the power supply circuit reaches a preset voltage value, the power supply outputted by the power supply quick start circuit is stopped; After the grid is powered on, the power supply is received from the power supply circuit; Obtaining a leakage current detection signal output by a leakage detection circuit after detecting a load voltage; When it is determined according to the leakage current detection signal that the leakage current of the load is greater than or equal to the preset current value, a circuit breaker signal is output to the circuit breaker drive circuit so that the circuit breaker drive circuit drives the power-off device to disconnect the power supply to the load.

2. The leakage digital detection and rapid protection method according to claim 1, characterized in that: When executing the step of obtaining the leakage current detection signal output by the leakage detection circuit after detecting the load voltage, the method further includes: Record the load leakage current data and leakage action waveform.

3. The leakage digital detection and rapid protection method according to claim 1, characterized in that: The leakage digital detection and rapid protection method further comprises the following steps: When it is determined according to the leakage current detection signal that the leakage current of the load is less than the preset current value, the power supply control signal is received, the power supply of the power grid to the load is adjusted, and the leakage current value of the load is detected and recorded at the same time.

4. The leakage digital detection and rapid protection method according to claim 1, characterized in that: The power supply circuit is a half-wave rectifier power supply circuit or a full-wave rectifier power supply circuit.

5. The leakage digital detection and rapid protection method according to claim 1, characterized in that: The following steps are also included: Receive a leakage threshold adjustment signal, and adjust the preset current value according to the leakage threshold adjustment signal.

6. A circuit breaker based on the digital leakage detection and rapid protection method according to any one of claims 1 to 5, characterized in that: include: a leakage detection circuit, wherein a detection terminal of the leakage detection circuit is used to connect to a load, and the leakage detection circuit is used to detect leakage current of the load and output a leakage detection signal; An MCU control chip, wherein the input end of the MCU control chip is connected to the output end of the leakage detection circuit, and the MCU control chip is used to output a circuit breaker signal to the circuit breaker drive circuit when it is determined that the leakage current of the load is greater than or equal to a preset current value according to the leakage detection signal; the MCU control chip is also used to record the leakage current parameter; A power supply quick start circuit, wherein the input end of the power supply quick start circuit is used to connect to the power grid, the output end of the power supply quick start circuit is connected to the power supply end of the MCU control chip, and the power supply quick start circuit is used to directly output power to the MCU control chip when the power grid is powered on; A circuit breaker drive circuit, wherein the input end of the circuit breaker drive circuit is connected to the output end of the MCU control chip, the output end of the circuit breaker drive circuit is used to connect a power-off device, and the circuit breaker drive circuit is used to drive the power-off device to disconnect the load power supply when a circuit breaker signal is received.

7. The circuit breaker according to claim 6, wherein: The circuit breaker further comprises: A power supply circuit, wherein the input end of the power supply circuit is used to connect to the power grid, and the output end of the power supply circuit is connected to the power supply end of the MCU control chip. The power supply circuit is used to convert the output power of the power grid and output it to the MCU control chip. When the power output by the power supply circuit reaches a preset voltage value, the MCU control chip stops receiving the power output by the power quick start circuit.

8. The circuit breaker according to claim 6, wherein: The power supply quick start circuit includes a first MOS tube, a first resistor, a second resistor, a first diode, a second diode and a third diode; The drain of the first MOS transistor is used to connect to a first power supply, the source of the first MOS transistor is connected to the first end of the first resistor, the second end of the first resistor, the cathode of the first diode, the cathode of the second diode, and the first end of the second resistor are interconnected, and connected to the power supply end of the MCU control chip, the anode of the second diode is used to connect to a second power supply, the second end of the second resistor, the cathode of the third diode, and the gate of the first MOS transistor are interconnected, and the anode of the first diode and the anode of the third diode are grounded.

9. The circuit breaker according to claim 6, wherein: The power supply quick start circuit includes a second MOS tube, a third resistor, a fourth resistor, a fourth diode and a fifth diode; The drain of the second MOS tube is used to connect to the third power supply, the source of the second MOS tube is connected to the first end of the third resistor, the second end of the third resistor, the first end of the fourth resistor and the cathode of the fourth diode are interconnected, and connected to the power supply end of the MCU control chip, the anode of the fourth diode is used to connect to the fourth power supply, the gate of the second MOS tube, the second end of the fourth resistor and the cathode of the fifth diode are interconnected, and the anode of the fifth diode is grounded.

10. The circuit breaker according to claim 6, wherein: The power supply quick start circuit includes a third MOS tube, a fifth resistor, a sixth resistor, a sixth diode, a first capacitor, a second capacitor, a first comparator and a first voltage stabilizer; The drain of the third MOS transistor is used to connect to the fifth power supply, the gate of the third MOS transistor, the first end of the fifth resistor and the output end of the first comparator are interconnected, the second end of the fifth resistor is connected to the power supply end of the MCU control chip, the source of the third MOS transistor is connected to the first end of the sixth resistor, the second end of the sixth resistor, the cathode of the sixth diode, the first end of the first capacitor and the input end of the first voltage regulator are interconnected, the anode of the sixth diode is used to connect to the sixth power supply, the output end of the first voltage regulator is connected to the first end of the second capacitor and to the power supply end of the MCU control chip, the first input end of the first comparator is connected to the power supply end of the MCU control chip, the second output end of the first comparator is used to connect to the sixth power supply, the second end of the first capacitor, the ground end of the first voltage regulator and the second end of the second capacitor are grounded.

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