A non-contact mains power disconnection sensing circuit

Abstract

The application relates to the technical field of circuit detection, in particular to a non-contact power-off induction detection circuit, which comprises a magnetic field induction element, an amplification unit, a driving unit, a waveform shaping unit and a judging unit. The magnetic field induction element is used for inducting the changing magnetic field around a wire and generating an induced current. The amplification unit is electrically connected with the magnetic field induction element to amplify the induced current to form an induced electromotive force. The input end of the driving unit is electrically connected with the output end of the amplification unit to convert the induced electromotive force into a periodic switching signal. The output end of the driving unit is electrically connected with the waveform shaping unit. The waveform shaping unit shapes the switching signal into a stable level signal and transmits the level signal to the judging unit to judge whether the wire is electrified. The effect of safely, stably and low-costly detecting whether the wire is electrified is achieved.

Description

Technical Field

[0001] This application relates to the field of circuit detection technology, and in particular to a non-contact mains power failure sensing detection circuit. Background Technology

[0002] In power systems, detecting the energized state of conductors is a crucial aspect of ensuring power safety and equipment maintenance. With the development of smart grids, the demand for conductor energization detection is increasing. This requires not only real-time and accurate acquisition of conductor energization information but also automated and remote detection capabilities to improve the operational efficiency and reliability of the power system. This is of great significance for timely detection of potential safety hazards, ensuring the normal operation of equipment, and optimizing the allocation of power resources. While traditional detection methods can meet basic detection needs to a certain extent, their limitations are becoming increasingly apparent with technological advancements and the increasing complexity of application scenarios.

[0003] Currently, there are various common detection methods in the field of conductor energization detection. Contact voltage probes are a more traditional method, acquiring voltage information through direct contact with the conductor. Non-contact electric field sensors utilize the principle of electric field induction, detecting energization without direct contact with the conductor. Additionally, capacitive detection uses changes in capacitance to determine whether a conductor is energized, while Hall effect sensors detect energization based on the Hall effect. In recent years, electromagnetic induction-based detection technologies have also gained attention. These technologies utilize changes in the magnetic field around the conductor to detect energization, offering advantages such as non-contact operation and high sensitivity. These detection methods have applications in various scenarios, but each also has its own limitations.

[0004] In existing technologies, contact-based detection methods pose significant safety hazards, as operators may suffer electric shock due to improper operation. Capacitive detection methods are easily affected by external environmental factors, leading to misjudgments and inaccurate results. Hall effect sensors require additional power supply equipment, increasing system complexity and cost. Furthermore, existing electromagnetic induction solutions involve complex signal processing circuits, making it difficult to generate stable voltage levels for direct microcontroller recognition, thus limiting their application in automated and remote detection. Utility Model Content

[0005] This application provides a non-contact mains power failure sensing detection circuit, which can achieve a simple structure and safely and stably detect whether a wire is energized.

[0006] The above-mentioned objective of this application is achieved through the following technical solution: This application provides a non-contact mains power failure induction detection circuit, including a magnetic field sensing element, an amplification unit, a driving unit, a waveform shaping unit, and a judgment unit. The magnetic field sensing element senses the changing magnetic field around the conductor and generates an induced current. The amplification unit is electrically connected to the magnetic field sensing element to amplify the induced current and form an induced electromotive force (EMF). The input terminal of the driving unit is electrically connected to the output terminal of the amplification unit to convert the induced EMF into a periodic switching signal. The output terminal of the driving unit is electrically connected to the waveform shaping unit, which shapes the switching signal into a stable level signal and transmits the level signal to the judgment unit to determine whether there is electricity on the conductor. In other words, the magnetic field amplification unit amplifies the induced current to form an induced EMF, the driving unit converts the induced EMF into a periodic switching signal, and the waveform shaping unit shapes the switching signal into a stable level signal and transmits the level signal to the judgment unit to determine whether there is electricity on the conductor. This achieves the effect of safely, stably, and cost-effectively detecting whether a conductor is energized. Because the magnetic field sensing element uses non-contact detection, it avoids the safety hazards of contact detection. The coordinated operation of each unit ensures stable signal processing and can generate a stable level signal that can be directly recognized by the judgment unit.

[0007] Preferably, the amplification unit includes transistors Q1 and Q2. The base of transistor Q1 is electrically connected to the magnetic field sensing element. The collectors of transistors Q1 and Q2 are respectively connected to a power supply. The emitter of transistor Q1 is electrically connected to the base of transistor Q2. The emitter of transistor Q2 outputs the induced electromotive force. Transistors Q1 and Q2, connected in this way, form a two-stage amplification circuit, which can effectively amplify the weak induced current, improve the signal strength, and provide better conditions for subsequent signal processing.

[0008] Preferably, the amplification unit includes a capacitor C1, one end of which is electrically connected to the magnetic field sensing element, and the other end of which is electrically connected to the base of the transistor Q1. The capacitor C1 acts as a DC-blocking and AC-passing capacitor, filtering out the DC component in the induced current and ensuring a purer signal input to the transistor Q1.

[0009] Preferably, the driving unit includes an optocoupler driving unit. The optocoupler provides electrical isolation, effectively preventing interference between upstream and downstream circuits and improving the circuit's anti-interference capability.

[0010] Preferably, the optocoupler driving unit includes an optocoupler U1, a transistor Q3, resistors R1 and R2. The base of transistor Q3 is electrically connected to the output terminal of the amplification unit via series resistor R1. The emitter of transistor Q3 is grounded, and the collector of transistor Q3 is electrically connected to the cathode of the input terminal of optocoupler U1. The anode of the input terminal and the collector of the output terminal of optocoupler U1 are respectively connected to the power supply. The emitter of the output terminal of optocoupler U1 is electrically connected to one end of resistor R2, and the other end of resistor R2 is grounded. Optocoupler U1 outputs a periodic switching signal. Resistor R1 acts as a current limiter to prevent excessive current from flowing into the base of transistor Q3 and damaging the transistor. When the induced electromotive force output by the amplification unit drives transistor Q3 to conduct and cut off, it will cause optocoupler U1 to periodically conduct and cut off, thereby outputting a periodic switching signal.

[0011] Preferably, the waveform shaping unit includes an integrating circuit.

[0012] Preferably, the integrating circuit includes a capacitor C3, resistors R3, R4, R5, R6, and a transistor Q4. One end of capacitor C3 and one end of resistor R3 are electrically connected to the output terminal of the driving unit, respectively. The other end of resistor R3 is electrically connected to one end of resistor R4 and the base of transistor Q4. The other ends of capacitor C3, resistor R4, and the emitter of transistor Q4 are grounded. The collector of transistor Q4 is electrically connected to one end of resistor R5 and one end of resistor R6, respectively. The other end of resistor R5 is connected to the power supply, and the other end of resistor R6 outputs a stable level signal. Capacitor C3 and resistors R3 and R4 form the main part of the integrating circuit, which can integrate the periodic switching signal output by the driving unit. The integrating circuit shapes the periodic switching signal into a stable level signal, for example, shaping a sine wave signal into a square wave signal, which is convenient for subsequent judgment unit to identify.

[0013] Preferably, the judgment unit includes a microcontroller, which can determine whether there is electricity on the conductor based on the level signal. The microcontroller receives a stable level signal output by the waveform shaping unit and determines whether there is electricity on the conductor based on the high or low level of the signal. When the level signal is high, the microcontroller determines that the conductor is energized; when the level signal is low, the microcontroller determines that the conductor is de-energized. The microcontroller has powerful computing and processing capabilities, enabling it to quickly and accurately analyze and judge the level signal, thus achieving real-time monitoring of the conductor's energized state.

[0014] In summary, this application includes at least the following beneficial technical effects: By using a magnetic field sensing element to non-contactly detect changes in the magnetic field around the conductor, the safety hazards of contact-based detection are avoided. An amplification unit effectively amplifies the induced current, improving signal strength. An optocoupler drive unit provides electrical isolation and signal conversion, enhancing the circuit's anti-interference capability. An integrating circuit shapes the periodic switching signal into a stable level signal, facilitating direct identification by the microcontroller. The entire circuit has a simple structure, low cost, and can safely and stably detect whether a conductor is energized. Compared to existing technologies, it represents a significant improvement and meets the needs of smart grids for automated and remote detection of conductor energization. Attached Figure Description

[0015] Figure 1 This is a circuit connection block diagram of the non-contact mains power failure sensing detection circuit in the embodiments of this application; Figure 2 This is a schematic diagram of the non-contact mains power failure sensing detection circuit in the embodiments of this application. Detailed Implementation

[0016] The following embodiments will help those skilled in the art to further understand the function of this application, but do not limit this application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application. These all fall within the protection scope of this application.

[0017] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0018] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0019] The present application will be further described in detail below with reference to the accompanying drawings.

[0020] Reference Figures 1-2The non-contact mains power failure induction detection circuit provided in this application includes a magnetic field sensing element, an amplification unit 10, a driving unit 20, a waveform shaping unit 30, and a judgment unit. The magnetic field sensing element senses the changing magnetic field around the conductor and generates an induced current. The amplification unit 10 is electrically connected to the magnetic field sensing element to amplify the induced current and form an induced electromotive force (EMF). The input terminal of the driving unit 20 is electrically connected to the output terminal of the amplification unit 10 to convert the induced EMF into a periodic switching signal. The output terminal of the driving unit 20 is electrically connected to the waveform shaping unit 30, which shapes the switching signal into a stable level signal and transmits the level signal to the judgment unit to determine whether there is electricity on the conductor. In other words, the magnetic field amplification unit 10 amplifies the induced current to form an induced EMF, the driving unit 20 converts the induced EMF into a periodic switching signal, and the waveform shaping unit 30 shapes the switching signal into a stable level signal and transmits the level signal to the judgment unit to determine whether there is electricity on the conductor. This achieves the effect of safely, stably, and cost-effectively detecting whether a conductor is energized. Because the magnetic field sensing element uses non-contact detection, it avoids the safety hazards of contact detection. The coordinated operation of each unit ensures stable signal processing and can generate a stable level signal that can be directly recognized by the judgment unit.

[0021] In some embodiments, the amplification unit 10 includes transistors Q1 and Q2 and capacitor C1. The base of transistor Q1 is electrically connected to the magnetic field sensing element, the collectors of transistors Q1 and Q2 are respectively connected to a power supply, the emitter of transistor Q1 is electrically connected to the base of transistor Q2, and the emitter of transistor Q2 outputs an induced electromotive force. In some embodiments, the amplification unit 10 includes capacitor C1, one end of which is electrically connected to the magnetic field sensing element, and the other end of which is electrically connected to the base of transistor Q1. Transistor Q1 is typically an NPN transistor, and its base is electrically connected to the magnetic field sensing element to receive the induced current. Transistor Q1 has a current amplification function, which can initially amplify the induced current. In practical applications, a field-effect transistor (FET) with similar amplification function can be used to replace transistor Q1. FETs have advantages such as high input impedance and low noise. Transistor Q2 can also be an NPN transistor. Its collector is connected to the power supply, just like the collector of transistor Q1. The emitter of transistor Q1 is electrically connected to the base of transistor Q2. This allows the current amplified by transistor Q1 to be further amplified by transistor Q2, and the emitter of transistor Q2 outputs an induced electromotive force. One end of capacitor C1 is electrically connected to the magnetic field sensing element, and the other end is electrically connected to the base of transistor Q1. Capacitor C1 acts as a DC-blocking and AC-passing capacitor, filtering out the DC component in the induced current and ensuring a purer signal input to transistor Q1. Capacitor C1 can be a ceramic capacitor, which has good stability and low loss; alternatively, a mica capacitor can be used, which has high precision and a small temperature coefficient. Transistors Q1 and Q2, connected in this way, form a two-stage amplifier circuit that effectively amplifies the weak induced current, improving signal strength and providing better conditions for subsequent signal processing.

[0022] In some embodiments, the amplification unit employs an existing transimpedance amplifier, which can directly convert the input induced current into an output voltage. Its core is an operational amplifier with a resistor connected in the feedback path.

[0023] Specifically, the driving unit 20 can be an optocoupler driving unit 20. For example... Figure 2In some embodiments, the optocoupler driving unit 20 includes an optocoupler U1, a transistor Q3, resistors R1 and R2. Transistor Q3 can be an NPN transistor, with its base electrically connected to the output terminal of the amplifier unit 10 via a series resistor R1. Resistor R1 limits current, preventing excessive current from flowing into the base of transistor Q3 and damaging it. The emitter of transistor Q3 is grounded, and its collector is electrically connected to the cathode of the input terminal of optocoupler U1. Optocoupler U1 provides electrical isolation, effectively preventing interference between upstream and downstream circuits and improving the circuit's anti-interference capability. The anode at the input terminal and the collector at the output terminal of optocoupler U1 are connected to the power supply, respectively. The emitter at the output terminal is electrically connected to one end of resistor R2, and the other end of resistor R2 is grounded, acting as a pull-up resistor. When the induced electromotive force output by the amplifier unit 10 drives transistor Q3 to turn on and off, it causes optocoupler U1 to periodically turn on and off, thereby outputting a periodic switching signal (such as a sine wave). In some cases, a magnetic coupler can be used to replace the optocoupler U1. The magnetic coupler can also achieve electrical isolation and signal transmission.

[0024] Specifically, the waveform shaping unit 30 employs an integrating circuit. In some embodiments, the integrating circuit includes a capacitor C3, resistors R3, R4, R5, R6, and a transistor Q4. One end of capacitor C3 and one end of resistor R3 are electrically connected to the output terminal of the driving unit 20, respectively. The other end of resistor R3 is electrically connected to one end of resistor R4 and the base of transistor Q4, respectively. The other ends of capacitor C3, resistor R4, and the emitter of transistor Q4 are grounded. Capacitor C3, resistors R3 and R4 form the main body of the integrating circuit, which can integrate the periodic switching signal output by the driving unit 20. Transistor Q4 can be an NPN transistor, with its collector electrically connected to one end of resistor R5 and one end of resistor R6, respectively. The other end of resistor R5 is connected to the power supply, and the other end of resistor R6 outputs a stable level signal. The integrating circuit shapes the periodic switching signal into a stable level signal, for example, shaping a sine wave signal into a square wave signal, which facilitates identification by the subsequent judgment unit. Resistor R5 acts as a pull-up resistor, ensuring a stable output signal level when transistor Q4 is turned on. In the integrating circuit, capacitor C3 can be an electrolytic capacitor, which has a larger capacitance and can better achieve the integration function; alternatively, a film capacitor can be used, which has the advantage of good high-frequency characteristics.

[0025] Specifically, the judgment unit employs a microcontroller. The microcontroller can be a common single-chip microcomputer, such as the 51 microcontroller or the STM32 microcontroller. The microcontroller receives a stable level signal output from the waveform shaping unit 30 and determines whether the wire is energized based on the high or low level of the signal. When the level signal is high, the microcontroller determines that the wire is energized; when the level signal is low, the microcontroller determines that the wire is de-energized. The microcontroller has powerful computing and processing capabilities, enabling it to quickly and accurately analyze and judge the level signal, achieving real-time monitoring of the wire's energized state.

[0026] This non-contact mains power failure induction detection circuit uses a magnetic field sensing element to detect changes in the magnetic field around the conductor without contact, avoiding the safety hazards of contact detection. The amplification unit 10 effectively amplifies the induced current, improving signal strength. The optocoupler drive unit 20 provides electrical isolation and signal conversion, enhancing the circuit's anti-interference capability. The integrating circuit shapes the periodic switching signal into a stable level signal, facilitating direct identification by the microcontroller. The entire circuit has a simple structure and low cost, enabling safe and stable detection of whether a conductor is energized. Compared to existing technologies, this represents a significant improvement and meets the needs of smart grids for automated and remote detection of conductor energization.

[0027] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above.

[0028] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A non-contact mains power failure sensing detection circuit, characterized in that, include: The system comprises a magnetic field sensing element, an amplification unit (10), a driving unit (20), a waveform shaping unit (30), and a judgment unit. The magnetic field sensing element is used to sense the changing magnetic field around the conductor and generate an induced current. The amplification unit (10) is electrically connected to the magnetic field sensing element to amplify the induced current and form an induced electromotive force. The input terminal of the driving unit (20) is electrically connected to the output terminal of the amplification unit (10) to convert the induced electromotive force into a periodic switching signal. The output terminal of the driving unit (20) is electrically connected to the waveform shaping unit (30). The waveform shaping unit (30) shapes the switching signal into a stable level signal and transmits the level signal to the judgment unit to determine whether there is electricity on the conductor.

2. The non-contact mains power failure sensing detection circuit according to claim 1, characterized in that, The amplification unit (10) includes transistors Q1 and Q2. The base of transistor Q1 is electrically connected to the magnetic field sensing element. The collectors of transistor Q1 and Q2 are respectively connected to the power supply. The emitter of transistor Q1 is electrically connected to the base of transistor Q2. The emitter of transistor Q2 outputs the induced electromotive force.

3. The non-contact mains power failure sensing detection circuit according to claim 2, characterized in that, The amplification unit (10) includes a capacitor C1, one end of which is electrically connected to the magnetic field sensing element, and the other end of which is electrically connected to the base of the transistor Q1.

4. The non-contact mains power failure sensing detection circuit according to claim 1, characterized in that, The driving unit (20) includes an optocoupler driving unit (20).

5. The non-contact mains power failure sensing detection circuit according to claim 4, characterized in that, The optocoupler driving unit (20) includes an optocoupler U1, a transistor Q3, a resistor R1, and a resistor R2. The base of the transistor Q3 is electrically connected to the output terminal of the amplification unit (10) via a series resistor R1. The emitter of the transistor Q3 is grounded. The collector of the transistor Q3 is electrically connected to the cathode of the input terminal of the optocoupler U1. The anode of the input terminal and the collector of the transistor at the output terminal of the optocoupler U1 are respectively connected to the power supply. The emitter of the transistor at the output terminal of the optocoupler U1 is electrically connected to one end of the resistor R2. The other end of the resistor R2 is grounded. The optocoupler U1 outputs a periodic switching signal.

6. The non-contact mains power failure sensing detection circuit according to claim 1, characterized in that, The waveform shaping unit (30) includes an integrating circuit.

7. The non-contact mains power failure sensing detection circuit according to claim 6, characterized in that, The integrating circuit includes a capacitor C3, resistors R3, R4, R5, R6 and a transistor Q4. One end of capacitor C3 and one end of resistor R3 are electrically connected to the output terminal of the driving unit (20), respectively. The other end of resistor R3 is electrically connected to one end of resistor R4 and the base of transistor Q4, respectively. The other end of capacitor C3, the other end of resistor R4 and the emitter of transistor Q4 are grounded, respectively. The collector of transistor Q4 is electrically connected to one end of resistor R5 and one end of resistor R6, respectively. The other end of resistor R5 is connected to the power supply, and the other end of resistor R6 outputs a stable level signal.

8. The non-contact mains power failure sensing detection circuit according to claim 1, characterized in that, The judgment unit includes a microcontroller, which can determine whether there is electricity on the wire based on the level signal.

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