Protection circuit for an electric circuit

Abstract

The application relates to a protection circuit of an electric circuit, which comprises a first switch circuit, a second switch circuit, a control unit and an information acquisition unit; the on-off response time of the second switch circuit is shorter than that of the first switch circuit. In a normal electric state, the first switch circuit is in a conducting state, and the second switch circuit is in a disconnected state; the information acquisition unit acquires the electric parameters of the electric circuit and transmits the electric parameters to the control unit; when the control unit judges that the electric circuit is faulty according to the electric parameters, the control unit controls the first switch circuit to be disconnected and / or controls the second switch circuit to be conducted. The self-protection circuit sets the first switch circuit on the main electric circuit and sets the second switch circuit on the bypass of the main electric circuit, so that the two switch circuits are used to ensure that the electric circuit is rapidly cut off when the electric circuit is faulty, and the purpose of protecting the load or human body is achieved.

Description

Technical Field

[0001] This application relates to the field of electrical protection technology, and in particular to protection circuits for electrical circuits. Background Technology

[0002] With the development of electricity management technology, the safe operation of electrical circuits has become a key research issue. In a typical electrical circuit, a circuit breaker (i.e., a switching circuit) is connected in series with the load (e.g., a light bulb), and the circuit breaker controls the connection and disconnection of the circuit. However, during use, if an electrical fault occurs (e.g., leakage, short circuit, surge), it can damage the load in the circuit. In particular, leakage can easily lead to electric shock. Therefore, to protect the load on the electrical circuit and prevent electric shock accidents, it is necessary to promptly disconnect the load side using a circuit breaker when a fault occurs.

[0003] However, the disconnection control time of commonly used circuit breakers is relatively long (whether it is a mechanical circuit breaker or a permanent magnet circuit breaker, the disconnection action response time is in the millisecond range), which cannot achieve high-speed disconnection, resulting in the inability to protect the load or human body in time when a fault occurs in the power circuit. Summary of the Invention

[0004] Therefore, it is necessary to provide a protection circuit for electrical circuits to address the problem of the inability to protect the load or human body in a timely manner when a fault occurs in the electrical circuit.

[0005] To achieve the above objectives, this application provides a protection circuit for an electrical circuit, including a first switching circuit, a second switching circuit, a control unit, and an information acquisition unit; the on / off response time of the second switching circuit is shorter than that of the first switching circuit.

[0006] The first terminal of the first switching circuit is connected to the control unit, the second terminal is used to connect to the power supply in the power circuit, and the third terminal is used to connect to the live wire in the power circuit; the control unit is connected to the information acquisition unit.

[0007] The first end of the second switching circuit is connected to the control unit, and the second end is connected between the third end of the first switching circuit and the load in the power circuit. The third end is used to connect the neutral wire in the power circuit and the load in the power circuit respectively, or the third end of the second switching circuit is used to ground.

[0008] In the normal power consumption state, the first switch circuit is in the conducting state and the second switch circuit is in the disconnected state; the information acquisition unit collects the electrical parameters of the power consumption circuit and transmits the electrical parameters to the control unit; when the control unit determines that a fault has occurred in the power consumption circuit based on the electrical parameters, it controls the first switch circuit to disconnect and / or controls the second switch circuit to conduct.

[0009] In one embodiment, when the control unit determines that a fault has occurred in the power circuit based on electrical parameters, it starts timing. When the first timing duration is greater than or equal to the first preset duration, if the control unit determines that the power circuit is still in a fault state based on electrical parameters, it controls the first switching circuit to open and / or controls the second switching circuit to open.

[0010] When the first timing duration is less than the first preset duration, the control unit determines that the power circuit has returned to normal based on the electrical parameters, and then maintains the first switching circuit in the conducting state and the second switching circuit in the disconnected state.

[0011] In one embodiment, the range of current in the power circuit exceeding the safe current threshold is divided into multiple current intervals, and a corresponding first preset duration is set for each current interval. The larger the current interval, the shorter the first preset duration.

[0012] In one embodiment, the control unit starts timing when the second switching circuit is turned on. When the second timing duration is greater than or equal to the second preset duration, the control unit determines that the power circuit is still in a fault state based on the electrical parameters, then maintains the second switching circuit in the on state and controls the first switching circuit to be turned off.

[0013] When the second timing duration is less than the second preset duration, the control unit determines that the power circuit has returned to normal based on the electrical parameters, then controls the second switching circuit to disconnect and keeps the first switching circuit in the conducting state.

[0014] In one embodiment, when the control unit determines that the electrical parameter is less than a first preset value and greater than a second preset value, it controls the first switching circuit to disconnect.

[0015] When the control unit determines that the electrical parameter is greater than or equal to the first preset value, it controls the first switch circuit to open and the second switch circuit to open.

[0016] In one embodiment, the control unit starts timing when it determines that the electrical parameter is less than a first preset value and greater than a second preset value. If the first timing duration is greater than or equal to the first preset duration, and the control unit determines that the electrical parameter is still less than the first preset value and greater than the second preset value, then it controls the first switch circuit to disconnect.

[0017] When the control unit determines that the electrical parameter is greater than or equal to the first preset value, it starts timing. If the first timing duration is greater than or equal to the first preset duration, and the control unit determines that the electrical parameter is still greater than or equal to the first preset value, it controls the first switch circuit to open and the second switch circuit to open.

[0018] In one embodiment, when the control unit determines that the electrical parameter is greater than or equal to the first preset value, it controls the second switch circuit to be turned on and starts timing. When the second timing duration is greater than or equal to the second preset duration, the control unit controls the first switch circuit to be turned off when it determines that the electrical parameter is still greater than or equal to the first preset value.

[0019] When the second timing duration is less than the second preset duration, the control unit determines that the electrical parameters are less than the second preset value, and then maintains the first switching circuit in the conducting state and controls the second switching circuit to be disconnected.

[0020] In one embodiment, the number of second switching circuits is at least two, wherein the third terminal of at least one second switching circuit is used for grounding;

[0021] When the control unit turns on the second switching circuit, it turns on all the second switching circuits.

[0022] or

[0023] When the control unit controls the second switching circuit to be turned on, it controls one of the second switching circuits to be turned on, and alternately controls the second switching circuits to be turned on in different control processes.

[0024] In one embodiment, the control unit records the first number of times the control of the first switch circuit switching state is executed, and the first number of executions is numbered according to the time sequence to obtain a first sequence, and the number in the first sequence is associated with the corresponding electrical parameters;

[0025] The control unit records the second execution number of controlling the switching state of the second switch circuit, and numbers the second execution number according to the time sequence to obtain the second sequence, and the number in the second sequence is associated with the corresponding electrical parameter;

[0026] The control unit generates a safety assessment report for the power circuit according to a preset test cycle, based on the first number of executions, the first sequence, the electrical parameters associated with the first sequence, the second number of executions, the second sequence, and the electrical parameters associated with the second sequence.

[0027] In one embodiment, the control unit includes a wireless module; the wireless module is used to wirelessly connect to the service unit; the control unit transmits monitoring information to the service unit through the wireless module; the monitoring information includes at least fault time information, fault location information, fault type information, number information of the first switching circuit, number information of the second switching circuit, and control information.

[0028] One of the above technical solutions has the following advantages and beneficial effects:

[0029] The protection circuits provided in the embodiments of this application include a first switching circuit, a second switching circuit, a control unit, and an information acquisition unit. The on / off response time of the second switching circuit is shorter than that of the first switching circuit. Under normal power usage, the first switching circuit is in a conducting state, and the second switching circuit is in a disconnected state. During power usage, the information acquisition unit collects the electrical parameters of the power circuit and transmits these parameters to the control unit. When the control unit determines that a fault has occurred in the power circuit based on the electrical parameters, it controls the first switching circuit to disconnect and / or controls the second switching circuit to connect. The protection circuit itself, by setting a first switching circuit on the main power circuit and a second switching circuit on the bypass of the main power circuit, utilizes two switching circuits to ensure high-speed disconnection of the power circuit in the event of a fault, thereby protecting the load or human body. Attached Figure Description

[0030] Figure 1 A schematic diagram of a protection circuit for the implementation of this application.

[0031] Figure 2 Another schematic diagram of the protection circuit provided for the implementation of this application. Detailed Implementation

[0032] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0033] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to and integrated with the other component, or there may be an intervening component present. The terms "mounted," "one end," "the other end," and similar expressions used in this document are for illustrative purposes only.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] To address the issue that traditional circuit breaker technology has a relatively long disconnection control time, making high-speed disconnection impossible and thus failing to provide timely protection for loads or human personnel when a fault occurs in the power circuit, such as... Figure 1 As shown, a protection circuit for an electrical circuit is provided, including a first switching circuit 11, a second switching circuit 13, a control unit 15, and an information acquisition unit 17. The first switching circuit 11 is connected to the main circuit of the electrical circuit and is used to control the on / off state of the main circuit. In one example, the first switching circuit 11 is a mechanical circuit breaker or a permanent magnet circuit breaker; the specific type of the first switching circuit 11 can be selected according to actual needs and is not specifically limited here. The second switching circuit 13 is located in the bypass of the electrical circuit and is used to control the on / off state of the bypass. It should be noted that the on / off response time of the second switching circuit 13 is shorter than that of the first switching circuit 11. Therefore, when control commands are sent to both the first and second switching circuits simultaneously, the second switching circuit 13 will formulate the control command faster than the first switching circuit 11. The on / off response time refers to the time required for the switching circuit to respond to the control command after receiving it.

[0036] Therefore, the on / off response time of the second switching circuit 13 must be shorter than that of the first switching circuit 11. In one example, such as... Figure 2 As shown, the second switching circuit 13 includes a first MOSFET M1 and a second MOSFET M2; the gate of the first MOSFET M1 and the gate of the second MOSFET M2 are connected to the control unit 15; the drain of the first MOSFET M1 is connected to the third terminal of the first switching circuit 11, and the source is connected to the source of the second MOSFET M2; the drain of the second MOSFET M2 is connected to the power supply and the load 19 in the power consumption circuit, respectively, or the drain of the second MOSFET M2 is used for grounding. In one example, the MOSFET can be an N-type MOSFET or a P-type MOSFET.

[0037] The specific connection relationship of the protection circuit of the power circuit in this application is as follows: the first end of the first switch circuit 11 is connected to the control unit 15, the second end is used to connect to the live wire in the power circuit, and the third end is used to connect to the load 19 in the power circuit. In one example, the load 19 can be electrical equipment such as light bulbs, televisions, computers, and washing machines.

[0038] The first end of the second switching circuit 13 is connected to the control unit 15, and the second end is connected between the third end of the first switching circuit 11 and the load 19 in the power circuit. The third end is used to connect the neutral wire in the power circuit and the load 19 in the power circuit respectively. Alternatively, the third end of the second switching circuit 13 is used to ground.

[0039] The control unit 15 is connected to the first switching circuit 11, the second switching circuit 13, and the information acquisition unit 17. In one example, the control unit 15 can be a microcontroller, a programmable logic control unit 15, or a system-on-a-chip.

[0040] In this circuit, under normal power usage conditions, the first switching circuit 11 is in the ON state, and the second switching circuit 13 is in the OFF state. At this time, current flows from the live wire, through the first switching circuit 11, through the load 19, and back to the neutral wire, or vice versa, from the neutral wire, through the load 19, through the first switching circuit 11, and back to the live wire, forming the main circuit of the power consumption circuit. The second switching circuit 13 constitutes a bypass of the power consumption circuit. Under normal power usage conditions, the second switching circuit 13 is in the OFF state, and no current flows through it.

[0041] The information acquisition unit 17 collects the electrical parameters of the power circuit and transmits them to the control unit 15. It should be noted that the electrical parameters collected by the information acquisition unit 17 can be one or any combination of current value, voltage value, and electromagnetic intensity. For example, if the electrical parameter is a current value, and the current value exceeds the safe current threshold, it indicates a fault in the power circuit. If the electrical parameter is electromagnetic intensity, and the electromagnetic intensity exceeds the safe electromagnetic intensity threshold, it indicates a fault in the power circuit. If the electrical parameter is a voltage value, and the voltage value exceeds the safe voltage threshold, it indicates a fault in the power circuit.

[0042] In one example, the information acquisition unit 17 includes a leakage current detection unit. The first terminal of the leakage current detection unit is connected to the control unit 15, the second terminal is connected between the second terminal of the second switching circuit 13 and the load 19 in the power consumption circuit, and the third terminal is connected between the third terminal of the second switching circuit 13 and the load 19 in the power consumption circuit. It should be noted that the leakage current detection unit is, but is not limited to, a Hall effect sensor or a fluxgate sensor. The leakage current detection unit detects the residual current on the load 19 side; if the residual current exceeds a first preset safe current threshold, it indicates a fault in the power consumption circuit.

[0043] It is worth mentioning that the first preset safe current threshold can be specifically set according to the actual leakage protection type of the product. Leakage protection types include AC type, A type, and B type products, and different first preset safe current thresholds can be designed for different leakage protection types. Among them, AC type leakage protection products are mainly used in general AC circuits, while A type leakage protection products are mainly used in AC power distribution lines and pulsating DC power distribution lines, and B type leakage protection products are mainly used in AC power distribution lines, pulsating DC power distribution lines, and electrical equipment that generates smooth DC current.

[0044] Different countries have different requirements for different types of leakage current protection. For example, in some embodiments, taking AC type leakage current protection products as an example, the first preset safe current threshold in China needs to be set to 30mA according to the CCC standard. That is, when the residual current is greater than 30mA, it indicates that there is a fault in the power circuit. In Europe, the first preset safe current threshold needs to be set to 10mA according to the CE standard, and in Europe, the first preset safe current threshold needs to be set to 6mA according to the UL standard.

[0045] Similarly, the requirements for setting the first preset safe current threshold for Type A and Type B leakage protection products will not be elaborated here.

[0046] In one example, the information acquisition unit 17 also includes a short-circuit detection unit. The first terminal of the short-circuit detection unit is connected to the control unit 15, the second terminal is connected to the second terminal of the second switching circuit 13, and the third terminal is connected to the second terminal of the leakage current detection unit. In one example, the short-circuit detection unit is, but is not limited to, a current transformer unit. In another example, the short-circuit detection unit includes a shunt resistor connected between the second terminal of the second switching circuit 13 and the load 19. The short-circuit detection unit detects the branch current passing through the input load 19 side; if the branch current exceeds a second preset safe current threshold, it indicates a fault in the power circuit.

[0047] Specifically, the aforementioned second preset safety current threshold is set based on the actual rated operating current. For example, in some embodiments, the second preset safety current threshold is set to twice the rated operating current. More specifically, common rated operating currents include, but are not limited to, current values ​​such as 10A, 16A, 32A, 63A, and 125A. For instance, when the rated operating current is set to 10A, the second preset safety current threshold is set to 20A. When the branch current exceeds 20A, it indicates a short circuit fault in the power circuit. Similarly, the same logic applies when the rated operating current is other values, which will not be elaborated upon here.

[0048] Of course, in other embodiments, depending on the actual protection requirements, the second preset safety current threshold is not limited to being set at twice the rated operating current, but can also be other values ​​greater than the rated operating current, which will not be elaborated here.

[0049] In one example, the information acquisition unit 17 also includes a surge detection unit. The first end of the surge detection unit is connected to the control unit 15, the second end is connected to the first end of the first switching circuit 11, and the third end is connected to the third end of the second switching circuit 13. It should be noted that the surge detection unit is used to detect the electromagnetic intensity of the electrical environment in which the power circuit is located. For example, when lightning strikes the vicinity of the power circuit, it generates an extremely strong electromagnetic field, causing a sudden increase in the current or voltage of the power circuit, thereby generating surge current or surge voltage. The surge detection unit can detect the surge current or surge voltage of the power circuit in the current environment. If the current value of the power circuit is greater than a preset surge current threshold, it indicates the presence of a surge current; if the voltage value of the power circuit is greater than a preset surge voltage threshold, it indicates the presence of a surge voltage. The presence of surge current or surge voltage can easily damage the load 19 on the load side of the power circuit.

[0050] Specifically, in some embodiments, at least one of a varistor, a TVS diode, and a gas discharge tube can be used as the voltage detection device in the surge detection unit. The surge voltage threshold setting is not limited; it can be set to be greater than the rated voltage threshold. For example, in some embodiments, the surge voltage threshold can be set to be greater than or equal to twice the rated voltage threshold. If the rated voltage threshold is 220V, then the surge voltage threshold is ≥440V (e.g., set to 470V). When the voltage value of the power circuit is greater than 470V, it indicates the presence of a surge voltage.

[0051] It is worth mentioning that the rated voltage threshold can be set according to the actual power consumption situation, and the surge voltage threshold can be set in the same way.

[0052] Specifically, in some embodiments, at least one of the following can be used as the current detection device in the surge detection unit: a current transformer, a shunt resistor, a TMR sensor, and a Hall effect sensor. The surge current threshold setting is not limited. For example, in some embodiments, the surge current threshold can be set to 100 times the rated current threshold. If the rated current threshold is 10A, then the surge current threshold is set to 1000A. When the current value of the power circuit is greater than 1000A, it indicates the presence of a surge current.

[0053] It is worth mentioning that the rated current threshold can be set according to the actual power consumption situation, and the surge current threshold can be set accordingly. When the control unit 15 determines that a fault has occurred in the power circuit based on electrical parameters (e.g., a short circuit, leakage current, lightning, etc.), the control unit 15 can independently control the first switching circuit 11 to disconnect, cutting off the main circuit of the power circuit, thereby cutting off the current to the load 19. It can independently control the second switching circuit 13 to conduct, conducting the bypass of the power circuit, so that the current flows from the live wire, through the first switching circuit 11, through the second switching circuit 13, and back to the neutral wire, or flows from the neutral wire, through the second switching circuit 13, through the first switching circuit 11, and back to the live wire, or when the second switching circuit 13 is grounded, the current starts from the live wire, flows through the second switching circuit 13 to the bottom, thereby cutting off the current to the load 19. It can also simultaneously control the first switching circuit 11 to disconnect and control the second switching circuit 13 to conduct, cutting off the main circuit of the power circuit and conducting the bypass of the power circuit.

[0054] Some faults in the power circuit may be transient and can be recovered instantly, without needing to disconnect the main power circuit. Repeatedly disconnecting the main power circuit for such faults would burden the first switching circuit 11 and the second switching circuit 13, and also cause inconvenience to the load 19. To address this issue, in one example, the control unit 15 starts timing when it determines a fault in the power circuit based on electrical parameters. If the timing duration is greater than or equal to a first preset duration, and the control unit 15 determines the power circuit is still faulty based on electrical parameters, it controls the first switching circuit 11 to disconnect and / or controls the second switching circuit 13 to connect. If the timing duration is greater than or equal to the first preset duration, and the control unit 15 determines the power circuit has returned to normal based on electrical parameters, it maintains the first switching circuit 11 in the connected state and the second switching circuit 13 in the disconnected state.

[0055] It should be noted that the control unit 15 uses its internal timing unit for timing. The control unit 15 collects the electrical parameters of the first switching circuit 11 and the second switching circuit 13 in real time through the information acquisition unit 17. When a fault is determined based on the electrical parameters at the current moment, the control unit 15 controls the timing unit to start timing from that current moment. In one example, the first preset duration is set based on the longest duration that the load 19 or a human body can withstand a fault in the electrical circuit, and the first preset duration is less than that longest duration. In another example, the first preset duration can be set based on the on / off response duration of the first switching circuit 11, and the first preset duration is less than the on / off response duration of the first switching circuit 11. In yet another example, the first preset duration can be set based on the on / off response duration of the second switching circuit 13, and the first preset duration is less than the on / off response duration of the second switching circuit 13.

[0056] When a power circuit experiences a leakage current, to ensure personal safety, the first preset duration should be set to account for the duration the human body can withstand the leakage current. This first preset duration should be shorter than the duration the human body can withstand. In one example, the range of current exceeding the safe current threshold in the power circuit is divided into multiple current intervals, and a corresponding first preset duration is set for each current interval. The larger the current interval, the shorter the first preset duration. For example, if the safe current threshold is 20A (amperes), each current exceeding the safe current threshold is divided into a current interval: 20A-30A, 30A-40A, 40A-50A, and so on. Correspondingly, the first preset duration for the 20A-30A current interval is 1 microsecond to 1 millisecond, for the 30A-40A current interval it is 1 microsecond to 5 microseconds, and for the 40A-60A current interval it is 1 microsecond to 2 microseconds.

[0057] If the fault in the power circuit lasts for a duration equal to or exceeding the first preset time, the control unit 15 may only control the first switching circuit 11 to disconnect, directly cutting off the main circuit of the power circuit. Alternatively, the control unit 15 may only control the second switching circuit 13 to conduct, directly conducting the bypass of the power circuit. The control unit 15 may also simultaneously control the first switching circuit 11 to disconnect and the second switching circuit 13 to conduct. However, if the fault in the power circuit recovers before the first preset time, the control unit 15 will not perform any control action on the first switching circuit 11 or the second switching circuit 13; the first switching circuit 11 will remain in the conducting state and the second switching circuit 13 will remain in the disconnected state.

[0058] The first switching circuit 11 is located on the main circuit of the power consumption circuit. To avoid power supply failure caused by a malfunction of the first switching circuit 11, in the embodiment of controlling the second switching circuit 13 to conduct, the first switching circuit 11 is controlled according to the following conditions to reduce the damage to the first switching circuit 11 caused by frequent switching operations and avoid accelerating the aging of the first switching circuit 11:

[0059] The control unit 15 starts timing when the second switching circuit 13 is turned on. When the second timing duration is greater than or equal to the second preset duration, the control unit 15 determines that the power circuit is still in a fault state based on the electrical parameters, then keeps the second switching circuit 13 in the on state and controls the first switching circuit 11 to turn off. When the second timing duration is less than the second preset duration, the control unit 15 determines that the power circuit has returned to normal based on the electrical parameters, then controls the second switching circuit 13 to turn off and keeps the first switching circuit 11 in the on state.

[0060] When a fault in the power circuit lasts for a duration equal to or exceeding the first preset duration, and the control unit 15 temporarily prevents damage to the load 19 or the human body by controlling the second switch circuit 13 to conduct, the control unit 15 controls the timing unit to start timing for the second timing duration. The control unit 15 also collects the electrical parameters of the first switch circuit 11 and the second switch circuit 13 in real time through the information acquisition unit 17 to determine if the power circuit is still in a fault state. If the fault in the power circuit continues to last for a duration equal to or exceeding the second preset duration, the control unit 15 controls the first switch circuit 11 to disconnect, cutting off the main circuit of the power circuit to eliminate the risk to the load 19 or the human body. This, along with the second switch circuit 13, forms a double safety net, improving the response speed of power cut-off and increasing electrical safety. If the fault in the power circuit returns to normal before exceeding the second preset duration, the control unit 15 does not control the first switch circuit 11, maintaining its conduction, and controls the second switch circuit 13 to disconnect. It should be noted that while the timing unit is timing the second timing duration, the first timing duration is still being recorded. In one example, the second preset duration is set based on the longest duration during which the load 19 or a human body can withstand a circuit fault. The second preset duration is less than this longest duration, and the sum of the first preset duration and the second preset duration is less than this longest duration. In another example, the second preset duration can be set based on the on / off response duration of the first switching circuit 11. The second preset duration is less than the on / off response duration of the first switching circuit 11, and the sum of the first preset duration and the second preset duration is less than the on / off response duration of the first switching circuit 11. In yet another example, the second preset duration can be set based on the on / off response duration of the second switching circuit 13. The second preset duration is less than the on / off response duration of the second switching circuit 13, and the sum of the first preset duration and the second preset duration is less than the on / off response duration of the second switching circuit 13.

[0061] When there is a leakage current in an electrical circuit, in order to ensure personal safety, the first preset duration setting should take into account the duration that the human body can withstand the leakage current. The first preset duration setting should be shorter than the duration that the human body can withstand. In one example, the range of current in the electrical circuit that exceeds the safe current threshold is divided into multiple current intervals, and a corresponding first preset duration and second preset duration are set for each current interval. The larger the current interval, the shorter the first preset duration and the second preset duration. For example, the safe current threshold is 20A (amperes). Each current exceeding the safe current threshold is divided into a current range. Specifically, there is a current range of 20A-30A, 30A-40A, 40A-50A, and so on. Correspondingly, the sum of the first and second preset durations for the 20A-30A current range is 1 microsecond to 1 millisecond; for the 30A-40A current range, it is 1 microsecond to 5 microseconds; and for the 40A-60A current range, it is 1 microsecond to 2 microseconds. The allocation of the first and second preset durations can be determined according to actual needs, such as the first preset duration being longer than the second preset duration, or the first preset duration being shorter than the second preset duration.

[0062] This application not only increases the protection of the first switching circuit 11 and the second switching circuit 13 and the flexibility of disconnecting the power circuit by adjusting the aforementioned timing duration, but also increases the protection of the first switching circuit 11 and the second switching circuit 13 and the flexibility of disconnecting the power circuit by adjusting the magnitude of the fault. In some cases, although a fault occurs in the power circuit, if the fault is not significant enough to affect the load 19 or the human body, or if it is within the acceptable range for the load 19 or the human body, it is not necessary to disconnect the power circuit, thus avoiding frequent switching of the first switching circuit 11 and the second switching circuit 13 and reducing their service life. In one example, the control unit 15 sends a maintenance signal to the outside world (e.g., staff computer, service unit, etc.) to remind staff to perform maintenance.

[0063] In this scenario, in one example, when the control unit 15 determines that the electrical parameter is less than a first preset value but greater than a second preset value, it controls the first switching circuit 11 to disconnect. When the control unit 15 determines that the electrical parameter is greater than or equal to the first preset value, it controls the first switching circuit 11 to disconnect and the second switching circuit 13 to connect. It should be noted that the first preset value is greater than the second preset value. In one example, the first preset value is set based on the load 19 or the limits acceptable to the human body, and the second preset value is 30% to 60% of the first preset value; for example, the second preset value is 40% or 50% of the first preset value. The first and second preset values ​​correspond to the type of electrical parameter. When the electrical parameter is a current value, both the first and second preset values ​​are current values; when the electrical parameter is electromagnetic intensity, both the first and second preset values ​​are electromagnetic intensity. When the electrical parameter is between the second and first preset values, it indicates a minor fault, which can be managed by controlling the first switching circuit 11 to disconnect. When the electrical parameters exceed the first preset value, it indicates that the fault is relatively large and may cause harm to the load 19 or the human body. Therefore, the control unit 15 controls the first switch circuit 11 to disconnect, cut off the main circuit of the power circuit and connect the second switch circuit 13 to conduct the bypass of the power circuit, realize double protection, and speed up the response speed of cutting off the power supply.

[0064] This application can also increase the protection of the first switching circuit 11 and the second switching circuit 13 and increase the flexibility of disconnecting the power circuit by combining the above-mentioned timing duration and fault magnitude.

[0065] In one example, the control unit 15 starts timing when it determines that the electrical parameter is less than a first preset value and greater than a second preset value. If the first timing duration is greater than or equal to the first preset duration, and the control unit 15 determines that the electrical parameter is still less than the first preset value and greater than the second preset value, then it controls the first switch circuit 11 to disconnect. It should be noted that if the first timing duration is less than the first preset duration, and the control unit 15 determines that the electrical parameter becomes less than the second preset value, then it controls the first switch circuit 11 to conduct.

[0066] The control unit 15 starts timing when it determines that the electrical parameter is greater than or equal to a first preset value. If the first timing duration is greater than or equal to the first preset duration, and the control unit 15 determines that the electrical parameter is still greater than or equal to the first preset value, then it controls the first switch circuit 11 to open and the second switch circuit 13 to open. It should be noted that if the first timing duration is less than the first preset duration, and the control unit 15 determines that the electrical parameter becomes less than a second preset value, then it controls the first switch circuit 11 to open and the second switch circuit 13 to open.

[0067] In one example, when the control unit 15 determines that the electrical parameter is greater than or equal to a first preset value, it controls the second switching circuit 13 to turn on and start timing. When the second timing duration is greater than or equal to a second preset duration, and the control unit 15 determines that the electrical parameter is still greater than or equal to the first preset value, it controls the first switching circuit 11 to turn off. When the second timing duration is less than the second preset duration, and the control unit 15 determines that the electrical parameter is less than the second preset value, it maintains the first switching circuit 11 in the on state and controls the second switching circuit 13 to turn off.

[0068] To further improve electrical safety, in one example, the number of second switch circuits 13 is at least two, wherein the third terminal of at least one second switch circuit 13 is used for grounding. For example, the number of second switch circuits 13 may be two, three, or four, and the specific number can be determined according to actual needs. By setting at least two second switch circuits 13 in the bypass, the protection function is enhanced, avoiding the risk that damage to the second switch circuit 13 when there is only one second switch circuit 13 will result in the inability to cut off the power supply.

[0069] The first control method: When the control unit 15 controls the second switch circuit 13 to be turned on, it controls all the second switch circuits 13 to be turned on. The second control method: When the control unit 15 controls the second switch circuit 13 to be turned on, it controls only one of the second switch circuits 13 to be turned on, and alternately controls the second switch circuits 13 to be turned on in different control processes. In other words, each time a fault occurs in the power circuit, when it is necessary to control the second switch circuit 13 to be turned on, it controls only one of the second switch circuits 13 to be turned on, and the same second switch circuit 13 is not used continuously.

[0070] To ensure the second switching circuit 13 functions effectively during power cutoff and to avoid the risk of a slower response time due to a malfunction in the second switching circuit 13, in one example, the control unit 15 checks for a fault in the second switching circuit 13. If a fault is detected, a warning signal is issued. It should be noted that the warning signal includes at least the corresponding number, location, and fault type of the faulty second switching circuit 13. The control unit 15 can issue warning signals to the operator's mobile terminal, computer terminal, or service unit to remind the operator to perform maintenance. In one example, when the power circuit is not supplying power, the control unit 15 sends a control command to the second switching circuit 13 and monitors whether the second switching circuit 13 responds to the control command to determine if the second switching circuit 13 is faulty. If it does not respond to the control command, the second switching circuit 13 is faulty.

[0071] To record the control status of the control unit 15 and analyze the recorded data, in one example, the control unit 15 includes a wireless module; the wireless module is used for wireless connection to the service unit; the control unit 15 transmits monitoring information to the service unit via the wireless module. It should be noted that the monitoring information includes at least fault time information, fault location information, fault type information, the numbering information of the first switching circuit 11, the numbering information of the second switching circuit 13, and control information. In one example, the control unit 15 transmits monitoring information to the service unit via the wireless module at a fixed period. In one example, the fixed period is 7 days, 15 days, or 30 days.

[0072] To prevent damage to the electrical circuit due to excessive instantaneous current, in one example, the protection circuit of the electrical circuit also includes a reactor protection unit. The first terminal of the reactor protection unit is connected to the second terminal of the first switching circuit 11, and the second terminal is connected to the third terminal of the second switching circuit 13. It should be noted that when the instantaneous current is excessive, the reactor protection unit absorbs part of the current to reduce the impact of the excessive instantaneous current on the electrical circuit.

[0073] To predict and provide early warnings about the safety performance of switching circuits, and to repair circuits with potential safety hazards in advance, eliminating potential safety risks before accidents occur, in one example, the control unit records the first number of times the control of the first switching circuit's switching state is executed. These executions are then numbered chronologically to obtain a first sequence, and the numbers in the first sequence are associated with corresponding electrical parameters. The control unit records the second number of times the control of the second switching circuit's switching state is executed. These second executions are then numbered chronologically to obtain a second sequence, and the numbers in the second sequence are associated with corresponding electrical parameters. Following a preset test cycle, the control unit generates a safety assessment report for the electrical circuit based on the first number of executions, the first sequence, the electrical parameters associated with the first sequence, the second number of executions, the second sequence, and the electrical parameters associated with the second sequence.

[0074] It should be noted that each time the control unit controls the first switch circuit to switch its state (from open to on, or from on to open), the control action is recorded and numbered (for example, in the form of 001, 002, 003, etc.). The number is then associated with the electrical parameters that caused the state switch. In other words, the electrical parameters on which the control unit based its control can be found by the number.

[0075] Similarly, each time the control unit controls the second switch circuit to switch states (from open to on, or from on to open), it records the control action and assigns a number (for example, in the form of 0001, 0002, 0003, etc.). The number is then associated with the electrical parameters that caused the state switch, meaning that the electrical parameters on which the control unit based its control can be found by the number.

[0076] In one example, the control unit can estimate the remaining service life of the first and second switching circuits by analyzing the number of times the first and second switching circuits switch states. By analyzing the sequence of switching states of the first and second switching circuits and the associated electrical parameters, the causes leading to the switching states of the first and second switching circuits, as well as the damage caused by the causes to the first and second switching circuits, can be analyzed, thereby generating a safety assessment report for the electrical circuit.

[0077] In one example, the reactor protection unit includes a reactor unit, a first resistor, a second resistor, and a capacitor unit. The first terminal of the reactor unit is connected to the live wire in the power circuit and the first terminal of the first resistor, respectively. The second terminal is connected to the second terminal of the first switching circuit 11 and the first terminal of the second resistor, respectively. The first terminal of the capacitor unit is connected to the second terminal of the first resistor, the second terminal is connected to the second terminal of the second resistor, and the third terminal is connected between the third terminal of the second switching circuit 13 and the neutral wire in the power circuit.

[0078] When the second switch circuit 13 is closed, the load 19 side is short-circuited, and the current in the power circuit quickly flows to the second switch circuit 13. At this time, the reactor unit can absorb part of the current in the power circuit and release the absorbed current through the capacitor unit, which avoids the situation where the instantaneous current of the second switch circuit 13 is too large and causes damage, and can effectively protect the normal operation of the second switch circuit 13.

[0079] The protection circuit of this application includes a first switching circuit 11, a second switching circuit 13, a control unit 15, and an information acquisition unit 17. The on / off response time of the second switching circuit 13 is shorter than that of the first switching circuit 11. Under normal power usage, the first switching circuit 11 is in a conducting state, and the second switching circuit 13 is in a disconnected state. During power usage, the information acquisition unit 17 collects the electrical parameters of the power circuit and transmits them to the control unit 15. When the control unit 15 determines that a fault has occurred in the power circuit based on the electrical parameters, it controls the first switching circuit 11 to disconnect and / or controls the second switching circuit 13 to connect. The protection circuit itself, by setting the first switching circuit 11 on the main power circuit and the second switching circuit 13 on the bypass of the main power circuit, achieves high-speed disconnection of the power circuit in the event of a fault, thereby protecting the load 19 or a person.

[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A protection circuit for an electrical circuit, characterized in that, It includes a first switching circuit, a reactor protection unit, a second switching circuit, a control unit, and an information acquisition unit; the on / off response time of the second switching circuit is shorter than that of the first switching circuit. The first terminal of the first switching circuit is connected to the control unit, the second terminal is used to connect to the live wire in the power circuit, and the third terminal is used to connect to the load in the power circuit; the control unit is connected to the information acquisition unit. The first end of the second switching circuit is connected to the control unit, and the second end is connected between the third end of the first switching circuit and the load in the power circuit. The third end is used to connect the neutral wire in the power circuit and the load in the power circuit respectively. Alternatively, the third end of the second switching circuit is used to ground. The first terminal of the reactor protection unit is connected to the second terminal of the first switching circuit, and the second terminal is connected to the third terminal of the second switching circuit; the reactor protection unit is used to absorb part of the current when the instantaneous current is too large, so as to reduce the impact of the instantaneous current on the power circuit. Under normal power consumption conditions, the first switching circuit is in the on state and the second switching circuit is in the off state; the information acquisition unit collects the electrical parameters of the power circuit and transmits the electrical parameters to the control unit; when the control unit determines that a fault has occurred in the power circuit based on the electrical parameters, it controls the first switching circuit to disconnect and / or controls the second switching circuit to connect. When the control unit determines that a fault has occurred in the power circuit based on the electrical parameters, it controls the circuit in the following manner: When the control unit determines that the electrical parameter is less than a first preset value and greater than a second preset value, it controls the first switching circuit to disconnect. When the control unit determines that the electrical parameter is greater than or equal to the first preset value, it controls the second switch circuit to be turned on and starts timing. When the second timing duration is greater than or equal to the second preset duration, the control unit controls the first switch circuit to be turned off if it determines that the electrical parameter is still greater than or equal to the first preset value. When the second timing duration is less than the second preset duration, the control unit maintains the first switch circuit in the on state and controls the second switch circuit to be turned off if it determines that the electrical parameter is less than the second preset value.

2. The protection circuit for the power circuit according to claim 1, characterized in that, When the control unit determines that the power circuit has a fault based on the electrical parameters, it starts timing. When the first timing duration is greater than or equal to the first preset duration, the control unit determines that the power circuit is still in a fault state based on the electrical parameters, and then controls the first switch circuit to disconnect and / or controls the second switch circuit to connect. When the first timing duration is less than the first preset duration, the control unit determines that the power circuit has returned to normal based on the electrical parameters, and then maintains the first switch circuit in the connected state and maintains the second switch circuit in the disconnected state.

3. The protection circuit for the power circuit according to claim 2, characterized in that, The current in the power circuit that exceeds the safe current threshold is divided into multiple current ranges, and a corresponding first preset duration is set for each current range. The larger the current range, the shorter the first preset duration.

4. The protection circuit for the power circuit according to claim 2, characterized in that, When the control unit controls the second switching circuit to be turned on, it starts timing. When the second timing duration is greater than or equal to the second preset duration, the control unit determines that the power circuit is still in a fault state based on the electrical parameters. Then, it maintains the second switching circuit in the on state and controls the first switching circuit to be turned off. When the second timing duration is less than the second preset duration, the control unit determines that the power circuit has returned to normal based on the electrical parameters, then controls the second switching circuit to disconnect and maintains the first switching circuit in the conducting state.

5. The protection circuit for the power circuit according to claim 1, characterized in that, When the control unit determines that the electrical parameter is less than the first preset value and greater than the second preset value, it starts timing. If the first timing duration is greater than or equal to the first preset duration, and the control unit determines that the electrical parameter is still less than the first preset value and greater than the second preset value, it controls the first switching circuit to disconnect. When the control unit determines that the electrical parameter is greater than or equal to the first preset value, it starts timing. If the first timing duration is greater than or equal to the first preset duration, and the control unit determines that the electrical parameter is still greater than or equal to the first preset value, it controls the first switching circuit to disconnect and the second switching circuit to turn on.

6. The protection circuit for an electrical circuit according to any one of claims 1 to 5, characterized in that, The number of the second switching circuits is at least two, wherein at least one of the third terminals of the second switching circuits is used for grounding; When the control unit controls the second switching circuit to be turned on, it controls all of the second switching circuits to be turned on. or When the control unit controls the second switching circuit to be turned on, it controls one of the second switching circuits to be turned on, and alternately controls the second switching circuits to be turned on in different control processes.

7. The protection circuit for the power circuit according to claim 6, characterized in that, The control unit records the first number of times the control of the first switching circuit switching state is executed, and the first number of executions is numbered according to the time sequence to obtain a first sequence, and the number in the first sequence is associated with the corresponding electrical parameter; The control unit records the second number of times the control circuit switches states, and numbers the second number of times according to the time sequence to obtain a second sequence, and the numbers in the second sequence are associated with the corresponding electrical parameters; The control unit generates a safety assessment report for the power circuit according to a preset test cycle, based on the first number of executions, the first sequence, the electrical parameters associated with the first sequence, the second number of executions, the second sequence, and the electrical parameters associated with the second sequence.

8. The protection circuit for an electrical circuit according to any one of claims 1 to 5, characterized in that, The control unit includes a wireless module; the wireless module is used to wirelessly connect to the service unit; the control unit transmits monitoring information to the service unit through the wireless module; the monitoring information includes at least fault time information, fault location information, fault type information, the numbering information of the first switching circuit, the numbering information of the second switching circuit, and control information.

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