Leakage current detection sensor and sensing device

Abstract

The utility model relates to a leakage current detection sensor and a sensing device, the leakage current detection sensor is used for detecting whether detected current leaks electricity or not, the leakage current detection sensor comprises a magnetic ring mutual inductor, a level overturning module and a controller, the controller is connected with the level overturning module and the magnetic ring mutual inductor, and the level overturning module is connected with the magnetic ring mutual inductor; the magnetic ring mutual inductor is used for receiving the detected current; the level flipping module is used for generating a level flipping signal according to the driving signals provided by the direct-current power supply and the controller; wherein a level inductive reactance signal is obtained after the level flipping signal is loaded to the magnetic ring mutual inductor; and the controller is used for collecting the inductive reactance areas of the plurality of level inductive reactance signals and comparing the plurality of voltage amplitudes in the inductive reactance areas of the plurality of level inductive reactance signals with the corresponding reference values so as to judge whether the detected current leaks electricity or not. The leakage current detection sensor provided by the utility model can accurately and quickly obtain a leakage current result, and is small in size, convenient for modular design and very simple in application.

Description

Technical Field

[0001] The utility model relates to the technical field of leakage protection, in particular to a leakage current detection sensor and a sensing device. Background Art

[0002] Leakage sensors are divided into AC type, A type, F type, B type, etc. At present, the design of these types of leakage current detection sensors is troublesome, the judgment result of leakage current is inaccurate, the judgment takes a long time, and the integration degree is not high, the occupied PCB area is large, etc., which is not conducive to the reduction of product volume, rapid research and development and modular design. Summary of the Utility Model

[0003] Based on this, in view of the problems in the above background art, it is necessary to provide a leakage current detection sensor and a sensing device, which can accurately and quickly obtain the leakage current result, the sensor has a small volume, is convenient for modular design, and the application is very simple.

[0004] The first aspect of the present application provides a leakage current detection sensor for detecting whether a measured current is leaking. The leakage current detection sensor includes: a magnetic ring transformer, a level inversion module and a controller. The controller is connected to both the level inversion module and the magnetic ring transformer, and the level inversion module is connected to the magnetic ring transformer;

[0005] The magnetic ring transformer receives the measured current;

[0006] The level inversion module is used to generate a level inversion signal according to the DC power supply and the driving signal provided by the controller; wherein, the level inversion signal is loaded onto the magnetic ring transformer to obtain a level inductive reactance signal;

[0007] The controller is used to collect the inductive reactance regions of multiple level inductive reactance signals, and compare multiple voltage amplitudes within the inductive reactance regions of multiple level inductive reactance signals with corresponding reference values to determine whether the measured current is leaking.

[0008] In one embodiment, the magnetic ring transformer includes an induction winding, and the measured current is a direct current; the controller includes:

[0009] A PWM waveform generator, connected to the level inversion module, for generating a driving signal;

[0010] An analog-to-digital converter, whose first end is connected to the level inversion detection module, and whose second end is connected to both the level inversion module and the second end of the induction winding, for cyclically collecting multiple voltage amplitudes within the inductive reactance regions of multiple level inductive reactance signals and performing analog-to-digital conversion.

[0011] In one embodiment, when the measured current is an alternating current, the leakage current detection sensor further includes:

[0012] A zero-crossing inversion module, which is used to invert the level of the collected alternating current at the zero-crossing moment to generate an alternating current zero-crossing inversion signal;

[0013] Wherein, the controller is connected to the zero-crossing inversion module and is used to collect the reactance regions of multiple said level reactance signals when receiving the alternating current zero-crossing inversion signal, and compare multiple voltage amplitudes within the reactance regions of multiple said level reactance signals with corresponding reference values to determine whether the alternating current is leaking.

[0014] In one embodiment, the magnetic core current transformer includes an induction winding; the controller includes:

[0015] A PWM waveform generator, which is connected to the level inversion module and is used to generate a driving signal;

[0016] A level inversion detection module, which is connected to the zero-crossing inversion module and is used to generate a trigger signal when detecting the alternating current zero-crossing inversion signal;

[0017] An analog-to-digital converter, whose first end is connected to the level inversion detection module, and whose second end is connected to both the level inversion module and the second end of the induction winding, and is used to perform analog-to-digital conversion when receiving the trigger signal.

[0018] In one embodiment, the analog-to-digital converter is also used to collect the reactance regions of multiple said level reactance signals, and compare multiple voltage amplitudes within the reactance regions of multiple said level reactance signals with corresponding reference values;

[0019] If the number of multiple voltage amplitudes within the reactance regions of multiple said level reactance signals that are the same as the corresponding reference values is greater than or equal to a preset number, and the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values are consistent, it is determined that the measured current is not leaking;

[0020] If the number of multiple voltage amplitudes within the reactance regions of multiple said level reactance signals that are the same as the corresponding reference values is greater than or equal to a preset number, and the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values are inconsistent, it is determined that the measured current is leaking;

[0021] If the number of multiple voltage amplitudes within the reactance regions of multiple said level reactance signals that are the same as the corresponding reference values is less than the preset number, and the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values are consistent, it is determined that the measured current is not leaking;

[0022] If the number of the same voltage amplitudes corresponding to multiple voltage amplitude values within the reactance region of multiple said level reactance signals is less than a preset number, and there is a discrepancy between the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values, it is determined that the measured current is leaking.

[0023] In one embodiment, the level flipping module includes:

[0024] A voltage dividing unit, whose first end is connected to a DC power supply, whose second end is grounded, and which performs voltage division processing on the DC power supply to obtain a voltage division signal;

[0025] A first level flipper, whose positive input terminal is connected to the PWM waveform generator, whose negative input terminal is connected to the third end of the voltage dividing unit, and whose output terminal is connected to the first end of the induction winding;

[0026] A voltage follower, whose first end is connected to the second end of the induction winding, and whose second end is connected to the third end of the voltage dividing unit;

[0027] Wherein, the first level flipper and the voltage follower jointly generate the level flipping signal.

[0028] In one embodiment, the voltage dividing unit includes:

[0029] A first voltage dividing resistor, whose first end is connected to a DC power supply, and whose second end serves as the third end of the voltage dividing unit;

[0030] A second voltage dividing resistor, whose first end is connected to the second end of the first voltage dividing resistor, and whose second end is grounded;

[0031] The voltage follower includes:

[0032] A first current limiting resistor, whose first end is connected to the second end of the induction winding;

[0033] A second current limiting resistor, whose first end is connected to the second end of the first current limiting resistor;

[0034] A second level flipper, whose positive input terminal is connected to the third end of the voltage dividing unit, whose negative input terminal is connected to the second end of the second current limiting resistor, and whose output terminal is connected to the second end of the first current limiting resistor.

[0035] In one embodiment, the leakage current detection sensor further includes:

[0036] A filter protection circuit, whose first end is connected to the first end of the induction winding, whose second end is connected to the second end of the induction winding, whose third end is connected to the analog-to-digital converter, and whose fourth end is connected to the analog-to-digital converter;

[0037] Among them, the filtering and protection circuit includes:

[0038] A first bidirectional TVS tube, whose first end is connected to the first end of the induction winding, and whose second end is connected to the second end of the induction winding;

[0039] A second bidirectional TVS tube, whose first end is connected to the second end of the induction winding, and whose second end is grounded;

[0040] A filtering resistor, whose first end is connected to the second end of the induction winding, and whose second end is connected to the analog-to-digital converter;

[0041] A filtering capacitor, whose first end is connected to the analog-to-digital converter, and whose second end is grounded.

[0042] In one embodiment, the magnetic core current transformer further includes a self-checking winding, and the first end of the self-checking winding is connected to a DC power supply; the controller further includes:

[0043] A third current-limiting resistor;

[0044] An input / output module, connected to the analog-to-digital converter and the zero-crossing inversion module, for outputting the leakage detection result and the AC zero-crossing inversion signal to an external device; and further for receiving a test signal and starting the controller to perform a self-detection test according to the test signal;

[0045] A self-checking control switch, connected to the second end of the self-checking winding via the third current-limiting resistor.

[0046] In one embodiment, the zero-crossing inversion module includes:

[0047] A first sampling resistor, whose first end is connected to the live wire of the mains;

[0048] A second sampling resistor, whose first end is connected to the neutral wire of the mains;

[0049] A third level inverter, whose negative input terminal is connected to the second end of the first sampling resistor, whose positive input terminal is connected to the second end of the second sampling resistor, and whose output terminal is connected to the level inversion detection module.

[0050] The second aspect of the present application provides a leakage current detection sensing device, including: a housing; a PCB board located inside the housing, on which the above-mentioned leakage current detection sensor is provided; a filling layer located inside the housing and covering the PCB board; and a sealing layer located inside the housing and provided on the surface of the filling layer.

[0051] In the leakage current detection sensor and the leakage current detection sensing device provided in the above embodiments, the leakage current detection sensor is used to detect whether the measured current is leaking. The leakage current detection sensor includes: a magnetic ring current transformer, a level inversion module, and a controller. The controller is connected to both the level inversion module and the magnetic ring current transformer, and the level inversion module is connected to the magnetic ring current transformer. The magnetic ring current transformer receives the measured current. The level inversion module is used to generate a level inversion signal according to the DC power supply and the drive signal provided by the controller. Among them, the level inversion signal is loaded onto the magnetic ring current transformer to obtain a level inductive reactance signal. The controller is used to collect the inductive reactance regions of multiple level inductive reactance signals, and compare multiple voltage amplitudes within the inductive reactance regions of the multiple level inductive reactance signals with corresponding reference values to determine whether the measured current is leaking. The leakage current detection sensor provided in this application can accurately and quickly obtain the leakage current result. The sensor is small in size, convenient for modular design, and very simple to apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0053] Figure 1 Schematic circuit structure diagram of the leakage current detection sensor provided in an embodiment of the present application;

[0054] Figure 2 Schematic circuit structure diagram of the leakage current detection sensor provided in another embodiment of the present application;

[0055] Figure 3 Schematic waveform diagram of the level inductive reactance signal provided in an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0058] In the case of using "including", "having", and "comprising" described herein, unless a clear limiting term is used, such as "only", "consisting of", etc., another component may also be added. Unless otherwise mentioned, terms in the singular form may include the plural form and should not be construed as having a quantity of one.

[0059] It should be understood that although terms such as "first" and "second" may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element.

[0060] In this application, unless otherwise clearly specified and defined, terms such as "connected" and "coupled" should be understood in a broad sense. For example, it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0061] To illustrate the above technical solutions of this application, specific embodiments will be described below.

[0062] In one embodiment of this application, as Figure 1 shown, a leakage current detection sensor is provided. The leakage current detection sensor includes: a magnetic ring current transformer 10, a level inversion module 30, and a controller 40; specifically, the controller 40 is connected to both the level inversion module 30 and the magnetic ring current transformer 10, and the level inversion module 30 is connected to the magnetic ring current transformer 10; the magnetic ring current transformer 10 receives the current to be measured; the level inversion module 30 is used to generate a level inversion signal according to the driving signal provided by the DC power supply and the controller 40; wherein, after the level inversion signal is loaded onto the magnetic ring current transformer 10, a level inductive reactance signal is obtained; the controller 40 is used to collect the inductive reactance regions of multiple level inductive reactance signals, and compare the multiple voltage amplitudes within the inductive reactance regions of the multiple level inductive reactance signals with the corresponding reference values to determine whether the current to be measured is leaking.

[0063] Specifically, the current to be measured includes a direct current or an alternating current, and the alternating current can be alternating current for household use, Figure 1The measured current passes through the magnetic ring current transformer; the reference value is the voltage amplitude of the level reactance signal in the reactance region when there is no leakage current in the measured current. Therefore, there are multiple reactance regions of the level reactance signal, and there are also multiple voltage amplitudes in each reactance region. Each voltage amplitude in each reactance region has a corresponding reference value.

[0064] In one embodiment, the measured current includes a direct current or an alternating current, and the alternating current can be alternating current mains. Figure 1 The measured current passes through the magnetic ring current transformer; the alternating current mains (live wire L and neutral wire N) first pass through the magnetic ring current transformer and then are connected to the electrical appliance. When there is no leakage abnormality at the electrical appliance end, the live wire current flowing into the magnetic ring will all flow back from the neutral wire after passing through the electrical appliance. That is, when there is no leakage at the electrical appliance end, the current flowing into the live wire L of the magnetic ring is equal to the current flowing back into the neutral wire N of the magnetic ring, and the two are exactly equal in magnitude. However, due to the opposite directions, the magnetic fluxes generated by the two in the magnetic ring just cancel each other out, and the magnetic flux change amount is equal to zero. If there is a leakage at the electrical appliance end, then the current flowing into the magnetic ring from the live wire L will not be equal to the current flowing back from the neutral wire N of the magnetic ring. Although the two are in opposite directions, the current magnitudes are different (the current difference is the residual current). Therefore, the magnetic fluxes generated by them in the magnetic ring cannot just cancel each other out, so the magnetic flux change amount is not equal to zero, and the induction coil of the magnetic ring will generate an induced current to form an induced voltage. The level flip signal is loaded on the magnetic ring current transformer 10. Since the magnetic ring current transformer 10 has an inductive impedance, the waveform of the level flip signal in the reactance region has a slow upward slope and a slow downward slope, as Figure 3 shown in the waveform diagram, which belongs to the case where there is no leakage in the alternating current.

[0065] In the leakage current detection sensor and the leakage current detection sensing device provided in the above embodiment, the leakage current detection sensor is used to detect whether the measured current is leaking. The leakage current detection sensor includes: a magnetic ring current transformer, a level flip module, and a controller. The controller is connected to both the level flip module and the magnetic ring current transformer, and the level flip module is connected to the magnetic ring current transformer; the magnetic ring current transformer receives the measured current; the level flip module is used to generate a level flip signal according to the driving signal provided by the DC power supply and the controller; wherein, the level flip signal is loaded onto the magnetic ring current transformer to obtain a level reactance signal; the controller is used to collect the reactance regions of multiple level reactance signals, and compare the multiple voltage amplitudes in the reactance regions of the multiple level reactance signals with the corresponding reference values to determine whether the measured current is leaking. The leakage detection sensor provided in this application can accurately and quickly obtain the leakage current result, the sensor is small in size, convenient for modular design, and very simple to apply.

[0066] In one embodiment, please refer to Figure 2 , the magnetic ring current transformer includes an induction winding. When the measured current is a direct current; the controller 40 includes:

[0067] A PWM waveform generator, connected to the level inversion module, for generating a driving signal;

[0068] An analog-to-digital converter, whose first end is connected to the level inversion detection module, and whose second end is connected to both the level inversion module and the second end of the induction winding, for cyclically collecting multiple voltage amplitudes within the reactance regions of multiple level reactance signals and performing analog-to-digital conversion.

[0069] In one embodiment, please continue to refer to Figure 2 , when the measured current is an alternating current, the leakage current detection sensor further includes:

[0070] A zero-crossing inversion module, for performing level inversion on the collected alternating current at the zero-crossing moment to generate an alternating current zero-crossing inversion signal;

[0071] Wherein, the controller is connected to the zero-crossing inversion module, and is used for, when receiving the alternating current zero-crossing inversion signal, collecting the reactance regions of multiple level reactance signals, comparing multiple voltage amplitudes within the reactance regions of the multiple level reactance signals with corresponding reference values, so as to determine whether the alternating current is leaking.

[0072] Specifically, when the alternating current is mains alternating current, the zero-crossing inversion module 20 includes: a first sampling resistor R1, a second sampling resistor R2, and a third level inverter U1; specifically, for the first sampling resistor R1, its first end is connected to the mains live wire L; for the second sampling resistor R2, its first end is connected to the mains neutral wire N; for the third level inverter U1, its negative input terminal is connected to the second end of the first sampling resistor R1, its positive input terminal is connected to the second end of the second sampling resistor R2, and its output terminal is connected to the level inversion detection module.

[0073] Further, please continue to refer to Figure 2 , the zero-crossing inversion module 20 further includes: a protection resistor R3, a first grounding resistor R4, a second grounding resistor R5, a first diode D1, and a second diode D2; for the protection resistor R3, its first end is connected to the second end of the first sampling resistor R1, and its second end is connected to the second end of the second sampling resistor R2; for the first grounding resistor R4, its first end is connected to the negative input terminal of the third level inverter U1, and its second end is grounded; for the second grounding resistor R5, its first end is connected to the second end of the first grounding resistor R4, and its second end is connected to the positive input terminal of the third level inverter U1; the first diode D1 and the second diode D2; wherein, the cathode of the first diode D1 is connected to the positive input terminal of the third level inverter U1, and the anode of the first diode D1 is connected to the negative input terminal of the third level inverter U1; the cathode of the second diode D2 is connected to the negative input terminal of the third level inverter U1, and the anode of the first diode D1 is connected to the positive input terminal of the third level inverter U1.

[0074] This application integrates the zero-crossing inversion module into the sensor. The product is modular, with a small volume and reliable detection. Moreover, the zero-crossing inversion module detects the zero-crossing of the alternating current as the starting point of sampling, eliminating the need for a large number of complex calculations in the controller to find the leakage moment, efficiently detecting the leakage condition of the mains electricity, and shortening the leakage detection time.

[0075] In one embodiment, please continue to refer to Figure 2 , the magnetic ring current transformer includes an induction winding L1; the controller 40 includes:

[0076] A PWM waveform generator, connected to the level inversion module 30, for generating a driving signal;

[0077] A level inversion detection module, connected to the zero-crossing inversion module 20, for generating a trigger signal when detecting an alternating current zero-crossing inversion signal;

[0078] An analog-to-digital converter ADC, whose first end is connected to the level inversion detection module, and whose second end is connected to both the level inversion module and the second end of the induction winding, for performing analog-to-digital conversion when receiving the trigger signal to convert the input level inductive reactance signal into a digital signal.

[0079] As an example, the driving signal may include, but is not limited to, a PWM waveform signal; when the sensor needs to be powered on or leakage current detection is required, the PWM waveform generator will continuously generate a driving signal.

[0080] For alternating current or direct current, the implementation principle of the analog-to-digital converter is the same, as follows: The analog-to-digital converter is also used to collect the inductive reactance regions of multiple level inductive reactance signals, compare the multiple voltage amplitudes and the corresponding reference values within the inductive reactance regions of the multiple level inductive reactance signals, and divide them into the following 4 cases: (1) If the number of multiple voltage amplitudes and the corresponding reference values that are the same within the inductive reactance regions of the multiple level inductive reactance signals is greater than or equal to the preset number, and the change trends of the inductive reactance regions of the multiple level inductive reactance signals and the corresponding reference values are consistent, it is determined that the measured current is not leaking; (2) If the number of multiple voltage amplitudes and the corresponding reference values that are the same within the inductive reactance regions of the multiple level inductive reactance signals is greater than or equal to the preset number, and the change trends of the inductive reactance regions of the multiple level inductive reactance signals and the corresponding reference values are inconsistent, it is determined that the measured current is leaking; (3) If the number of multiple voltage amplitudes and the corresponding reference values that are the same within the inductive reactance regions of the multiple level inductive reactance signals is less than the preset number, and the change trends of the inductive reactance regions of the multiple level inductive reactance signals and the corresponding reference values are consistent, it is determined that the measured current is not leaking; (4) If the number of multiple voltage amplitudes and the corresponding reference values that are the same within the inductive reactance regions of the multiple level inductive reactance signals is less than the preset number, and the change trends of the inductive reactance regions of the multiple level inductive reactance signals and the corresponding reference values are inconsistent, it is determined that the measured current is leaking.

[0081] The analog-to-digital converter ADC can only collect the voltage amplitude of the level inductive reactance signal as a reference value. That is to say, it can also only collect the voltage amplitude of the real-time level inductive reactance signal in the inductive reactance region.

[0082] In one embodiment, please continue to refer to Figure 2 , the level inversion module 30 includes: a voltage division unit 31, whose first end is connected to the DC power supply VCC, and whose second end is grounded, to perform voltage division on the DC power supply VCC to obtain a divided voltage signal (1 / 2VCC); a first level inverter U2, whose positive input terminal is connected to the PWM waveform generator, whose negative input terminal is connected to the third end of the voltage division unit 31, and whose output terminal is connected to the first end of the induction winding L1; a voltage follower 32, whose first end is connected to the second end of the induction winding L1, and whose second end is connected to the third end of the voltage division unit 31; wherein, the first level inverter U2 and the voltage follower 32 jointly generate a level inversion signal.

[0083] Further, please continue to refer to Figure 2 , the voltage division unit 31 includes: a first voltage division resistor R5, whose first end is connected to the DC power supply VCC, and whose second end serves as the third end of the voltage division unit 31; a second voltage division resistor R6, whose first end is connected to the second end of the first voltage division resistor R5, and whose second end is grounded to GND.

[0084] Further, please continue to refer to Figure 2 , the voltage follower 32 includes: a first current limiting resistor R9, whose first end is connected to the second end of the induction winding L1; a second current limiting resistor R10, whose first end is connected to the second end of the first current limiting resistor R9; a second level inverter U3, whose positive input terminal is connected to the third end of the voltage division unit 31, whose negative input terminal is connected to the second end of the second current limiting resistor R10, and whose output terminal is connected to the second end of the first current limiting resistor R9.

[0085] Specifically, both the first level inverter U2 and the second level inverter U3 are used to perform a level inversion when the sensitive edge of the drive signal passes through the divided voltage of the divided voltage signal, and jointly generate a level inversion signal. Among them, the sensitive edge can be a rising edge or a falling edge. The level inversion signal is in phase with the drive signal.

[0086] In the above text, the first level inverter U2, the second level inverter U3, and the third level inverter U1 can all include, but are not limited to, operational amplifiers or voltage comparators.

[0087] In one embodiment, please continue to refer to Figure 2, the leakage current detection sensor further includes: a filter protection circuit 50, whose first end is connected to the first end of the induction winding L1, whose second end is connected to the second end of the induction winding L1, whose third end is connected to the analog-to-digital converter ADC, and whose fourth end is connected to the analog-to-digital converter ADC.

[0088] Specifically, the filter protection circuit includes: a first bidirectional TVS tube TVS1, whose first end is connected to the first end of the induction winding L1 and whose second end is connected to the second end of the induction winding L1; a second bidirectional TVS tube TVS2, whose first end is connected to the second end of the induction winding L1 and whose second end is grounded; a filter resistor R7, whose first end is connected to the second end of the induction winding L1 and whose second end is connected to the analog-to-digital converter; a filter capacitor C1, whose first end is connected to the analog-to-digital converter and whose second end is grounded. For the two bidirectional TVS tubes, when the voltage value of the leakage current exceeds the threshold voltage of the bidirectional TVS tube, the bidirectional TVS tube will absorb and discharge the spike voltage to ensure that the AC voltage or DC voltage input into the controller is within the safe voltage range during the operation of the sensor.

[0089] In one embodiment, please continue to refer to Figure 2 , the magnetic ring current transformer further includes a self-checking winding L2, whose first end is connected to the DC power supply VCC for power-on self-checking and self-calibration; the controller 40 further includes: a third current-limiting resistor R8; an input / output module, connected to the analog-to-digital converter and the zero-crossing inversion module 20, for outputting the leakage current detection result and the AC zero-crossing inversion signal to an external device; and further for receiving a test signal and starting the controller 40 to perform a self-detection test according to the test signal; a self-check control switch, connected to the second end of the self-checking winding L2 via the third current-limiting resistor, responsible for turning on or off the self-check analog current flowing through the third current-limiting resistor R8, and the self-check analog current is provided by the DC power supply VCC.

[0090] It should be noted that the input / output module can output the leakage current detection result of the measured current, that is, it can output the leakage current detection result of the AC current or DC current.

[0091] Specifically, the controller 40 sets a high level based on the test signal to control the self-check control switch to disconnect, that is, to turn off the current of the self-checking winding of the magnetic ring coil, and the controller 40 sets a low level based on the test signal to control the self-check control switch to close to turn on the current of the self-checking winding, flowing through R8, to determine whether the leakage current detection sensor is working properly.

[0092] Specifically, the input / output module includes three external output ports, namely S-OUT, TEST, and Z-OUT. TEST is the port for the external device to input the test signal, Z-OUT is the port for outputting the zero-crossing inversion signal to the external device, and S-OUT is the port for outputting the leakage current detection result to the external device.

[0093] In another embodiment of the present application, a leakage current detection sensing device is further provided. The leakage current detection sensing device includes: a housing; a PCB board located inside the housing, on which the above-mentioned leakage current detection sensor is provided; a filling layer located inside the housing and covering the PCB board; and a sealing layer located inside the housing and disposed on the surface of the filling layer.

[0094] As an example, the material of the housing may include but is not limited to plastics, metals, ceramics, etc.; the material of the sealing layer may include but is not limited to any one or a combination of silicone or resin.

[0095] For the leakage current detection sensing device provided in the above embodiment, by setting the housing, placing the above-mentioned leakage current detection sensor on the PCB board, the PCB board is disposed inside the housing, and the PCB board is covered with a filling layer, and a sealing layer is provided on the upper surface of the filling layer, thereby completing the encapsulation of the leakage current detection sensor. The overall structure is small and easy to carry, making the later application simple and feasible. At the same time, it can prevent high-temperature and high-voltage electric shock, and can also prevent corrosion and moisture, and is suitable for a variety of complex environments.

[0096] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope described in this specification.

[0097] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A leakage current detection sensor, characterized in that, Used to detect whether the measured current is leaking electricity, including: a magnetic ring current transformer, a level inversion module, and a controller. The controller is connected to both the level inversion module and the magnetic ring current transformer, and the level inversion module is connected to the magnetic ring current transformer; The magnetic ring current transformer receives the measured current; The level inversion module is used to generate a level inversion signal according to the DC power supply and the drive signal provided by the controller. Among them, after the level inversion signal is loaded onto the magnetic ring current transformer, a level inductive reactance signal is obtained; The controller is used to collect the inductive reactance regions of multiple level inductive reactance signals, and compare multiple voltage amplitudes within the inductive reactance regions of multiple level inductive reactance signals with corresponding reference values to determine whether the measured current is leaking electricity.

2. The leakage current detection sensor according to claim 1, characterized in that, The magnetic ring current transformer includes an induction winding, and the measured current is a direct current. The controller includes: A PWM waveform generator, connected to the level inversion module, for generating a drive signal; An analog-to-digital converter, its first end is connected to the level inversion detection module, and its second end is connected to both the level inversion module and the second end of the induction winding, for cyclically collecting multiple voltage amplitudes within the inductive reactance regions of multiple level inductive reactance signals and performing analog-to-digital conversion.

3. The leakage current detection sensor according to claim 1, characterized in that When the measured current is an alternating current, the leakage current detection sensor further includes: A zero-crossing inversion module, used to perform level inversion on the collected alternating current at the zero-crossing moment to generate an alternating current zero-crossing inversion signal; Among them, the controller is connected to the zero-crossing inversion module, and is used to collect the inductive reactance regions of multiple level inductive reactance signals when receiving the alternating current zero-crossing inversion signal, and compare multiple voltage amplitudes within the inductive reactance regions of multiple level inductive reactance signals with corresponding reference values to determine whether the alternating current is leaking electricity.

4. The leakage current detection sensor according to claim 3, characterized in that, The magnetic ring current transformer includes an induction winding. The controller includes: A PWM waveform generator, connected to the level inversion module, for generating a drive signal; A level inversion detection module, connected to the zero-crossing inversion module, for generating a trigger signal when detecting the alternating current zero-crossing inversion signal; An analog-to-digital converter, its first end is connected to the level inversion detection module, and its second end is connected to both the level inversion module and the second end of the induction winding, for performing analog-to-digital conversion when receiving the trigger signal.

5. The leakage current detection sensor according to claim 4, characterized in that, The magnetic ring current transformer further includes a self-check winding, and the first end of the self-check winding is connected to the DC power supply. The controller further includes: A third current-limiting resistor; An input / output module, connected to the analog-to-digital converter and the zero-crossing inversion module, for outputting the leakage detection result and the alternating current zero-crossing inversion signal to an external device; and is also used to receive a test signal and start the controller to execute a self-test according to the test signal; A self-check control switch, connected to the second end of the self-check winding via the third current-limiting resistor.

6. The leakage current detection sensor according to claim 2 or 4, characterized in that, The analog-to-digital converter is also used to collect the inductive reactance regions of multiple level inductive reactance signals, and compare multiple voltage amplitudes within the inductive reactance regions of multiple level inductive reactance signals with corresponding reference values; If the number of the same voltage amplitudes and the corresponding reference values in the reactance regions of multiple said level reactance signals is greater than or equal to a preset number, and the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values are consistent, it is determined that the measured current is not leaking; If the number of the same voltage amplitudes and the corresponding reference values in the reactance regions of multiple said level reactance signals is greater than or equal to a preset number, and the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values are inconsistent, it is determined that the measured current is leaking; If the number of the same voltage amplitudes and the corresponding reference values in the reactance regions of multiple said level reactance signals is less than the preset number, and the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values are consistent, it is determined that the measured current is not leaking; If the number of the same voltage amplitudes and the corresponding reference values in the reactance regions of multiple said level reactance signals is less than the preset number, and the change trends of the reactance regions of multiple said level reactance signals and the change trends of the corresponding reference values are inconsistent, it is determined that the measured current is leaking.

7. The leakage current detection sensor according to claim 2 or 4, characterized in that, The level inversion module includes: A voltage dividing unit, whose first end is connected to a DC power supply, and whose second end is grounded, to perform voltage dividing processing on the DC power supply to obtain a voltage dividing signal; A first level inverter, whose positive input terminal is connected to the PWM waveform generator, whose negative input terminal is connected to the third end of the voltage dividing unit, and whose output terminal is connected to the first end of the induction winding; A voltage follower, whose first end is connected to the second end of the induction winding, and whose second end is connected to the third end of the voltage dividing unit; Wherein, the first level inverter and the voltage follower jointly generate the level inversion signal.

8. The leakage current detection sensor according to claim 7, wherein The voltage dividing unit includes: A first voltage dividing resistor, whose first end is connected to the DC power supply, and whose second end serves as the third end of the voltage dividing unit; A second voltage dividing resistor, whose first end is connected to the second end of the first voltage dividing resistor, and whose second end is grounded; The voltage follower includes: A first current limiting resistor, whose first end is connected to the second end of the induction winding; A second current limiting resistor, whose first end is connected to the second end of the first current limiting resistor; A second level inverter, whose positive input terminal is connected to the third end of the voltage dividing unit, whose negative input terminal is connected to the second end of the second current limiting resistor, and whose output terminal is connected to the second end of the first current limiting resistor.

9. The leakage current detection sensor according to claim 2 or 4, characterized in that, It further includes: A filter protection circuit, whose first end is connected to the first end of the induction winding, whose second end is connected to the second end of the induction winding, whose third end is connected to the analog-to-digital converter, and whose fourth end is connected to the analog-to-digital converter; Wherein, the filter protection circuit includes: A first bidirectional TVS tube, whose first end is connected to the first end of the induction winding, and whose second end is connected to the second end of the induction winding; A second bidirectional TVS tube, whose first end is connected to the second end of the induction winding, and whose second end is grounded; A filter resistor, whose first end is connected to the second end of the induction winding, and whose second end is connected to the analog-to-digital converter; A filter capacitor, whose first end is connected to the analog-to-digital converter, and whose second end is grounded.

10. A leakage current detection sensing device, characterized in that, Comprising: A housing; A PCB board, located inside the housing, on which is provided a leakage current detection sensor as described in any one of claims 1-9; A filling layer, located inside the housing, and covering the PCB board; A sealing layer, located inside the housing, and provided on the surface of the filling layer.

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