A leakage detection device and method based on half-saturation magnetic induction intensity

Abstract

The present invention discloses a leakage detection device and method based on semi-saturated magnetic induction intensity. Compared with the prior art, the present method places a magnetic core at a preset distance from the current to be measured, sends an excitation signal to the excitation coil on the magnetic core through an excitation signal module, and forms the excitation signal into an asymmetric positive and negative alternating current through a configuration resistor; obtains the back electromotive force generated by the excitation coil, and integrates the back electromotive force through an integration circuit to obtain a waveform signal; extracts the peak-to-peak value from the waveform signal through a signal processing module, and determines the actual current value of the current to be measured according to a preset corresponding table; determines whether the current to be measured has leakage according to the actual current value of the current to be measured and the allowable working range of the current to be measured. The cost of leakage detection of electrical equipment is reduced, the accuracy of leakage detection is improved, and the duty cycle requirements of the excitation source are loose, and the requirements for the excitation waveform are low.

Description

Technical Field

[0001] The present invention belongs to the technical field of leakage detection, and in particular relates to a leakage detection device and method based on half-saturation magnetic induction intensity. Background Art

[0002] Electricity is a widely used energy source in modern society, affecting people's daily lives, especially some low-voltage electrical equipment in life or business. The leakage current inside these electrical equipment is usually small and not easy to be found, but it poses a certain threat to the safety of electrical equipment and the personal safety of users.

[0003] In the prior art, leakage detection of low-voltage electrical equipment is usually performed based on magnetic induction intensity. However, the prior art solutions all require negative feedback control and compensation, have high requirements for the feedback control of the excitation source, and have high requirements for the duty cycle of the excitation signal. The solution cost is high and the detection accuracy is not high enough.

[0004] Therefore, how to reduce the cost of leakage detection of electrical equipment and improve the accuracy of leakage detection is a technical problem to be solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems of high cost and low detection accuracy of leakage detection of electrical equipment in the prior art.

[0006] To achieve the above technical objectives, on the one hand, the present invention provides a leakage detection device based on semi-saturated magnetic induction intensity, the device comprising an excitation signal module, a configuration resistor, an excitation coil, a magnetic core, an integration circuit and a signal processing module, wherein:

[0007] The excitation coil is wound on the magnetic core, and both ends of the excitation coil are connected to the excitation signal module and the integration circuit. One end of the excitation coil is connected to the excitation signal module with the configuration resistor arranged in the middle, and the integration circuit is connected to the signal processing module.

[0008] Furthermore, the integration circuit is specifically used to obtain the back electromotive force of the excitation coil and integrate it to obtain a waveform signal.

[0009] Furthermore, the signal processing module is specifically used to extract the peak-to-peak value from the waveform signal, and determine the actual current value of the current to be measured according to a preset corresponding table.

[0010] On the other hand, the present invention also provides a leakage detection method based on half-saturation magnetic induction intensity, the method comprising:

[0011] The magnetic core is placed at a preset distance from the current to be measured, an excitation signal is sent to the excitation coil on the magnetic core through an excitation signal module, and the excitation signal is transformed into an asymmetric positive and negative alternating current through a configured resistor;

[0012] Acquire the back electromotive force generated by the excitation coil, and integrate the back electromotive force through an integration circuit to obtain a waveform signal;

[0013] Extracting the peak-to-peak value from the waveform signal through a signal processing module, and determining the actual current value of the current to be measured according to a preset corresponding table;

[0014] Whether leakage occurs in the current to be measured is determined according to the actual current value of the current to be measured and the allowable working range of the current to be measured.

[0015] Furthermore, before sending an excitation signal to the excitation coil through the excitation signal module, the method also includes determining the saturation magnetic induction intensity of the magnetic core, the minimum saturation current for the magnetic core to reach saturation, the number of turns of the excitation coil and the resistance value of the configuration resistor based on the property information of the magnetic core.

[0016] Furthermore, the positive peak value of the alternating current can make the magnetic induction intensity of the magnetic core reach saturation, and the negative peak value of the alternating current can make the magnetic induction intensity value of the magnetic core zero.

[0017] Furthermore, the integral processing is specifically determined by the following formula:

[0018] ,

[0019] In the formula, B is the magnetic induction intensity of the excitation coil, is the back electromotive force, S is the core cross section, is the microvariable at time t.

[0020] The present invention provides a leakage detection device and method based on semi-saturated magnetic induction intensity. Compared with the prior art, the present method places a magnetic core at a preset distance from the current to be measured, sends an excitation signal to the excitation coil on the magnetic core through an excitation signal module, and forms the excitation signal into an asymmetric positive and negative alternating current through a configuration resistor; obtains the back electromotive force generated by the excitation coil, and integrates the back electromotive force through an integration circuit to obtain a waveform signal; extracts the peak-to-peak value from the waveform signal through a signal processing module, and determines the actual current value of the current to be measured according to a preset corresponding table; determines whether the current to be measured has leakage according to the actual current value of the current to be measured and the allowable working range of the current to be measured. The cost of leakage detection of electrical equipment is reduced, the accuracy of leakage detection is improved, and the duty cycle requirements of the excitation source are loose, and the requirements for the excitation waveform are low. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the flow of the leakage detection method based on the semi-saturation magnetic induction intensity provided in the embodiment of this specification;

[0023] Figure 2 The figure shows a schematic diagram of the structure of a leakage detection device based on half-saturation magnetic induction intensity provided in an embodiment of this specification;

[0024] Figure 3 It is a schematic diagram showing the hysteresis loop in different saturation conditions in the embodiment of this specification;

[0025] Figure 4 Shown is a schematic diagram of a hysteresis loop after half-saturation modulation in an embodiment of this specification. DETAILED DESCRIPTION

[0026] In order to enable ordinary technicians in this field to better understand the technical solutions in this specification, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] like Figure 1The flowchart of the leakage detection method based on half-saturation magnetic induction intensity provided by the embodiment of this specification is shown. Although this specification provides the method operation steps or device structure shown in the following embodiments or drawings, the method or device may include more or fewer operation steps or module units after partial merger based on routine or no creative labor. In the steps or structures where there is no necessary causal relationship logically, the execution order of these steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiments of this specification or drawings. When the method or module structure is applied in the actual device, server or terminal product, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiment or drawings.

[0028] As described in the background technology, in the prior art, leakage detection of low-voltage electrical equipment is usually performed based on magnetic induction intensity, but the prior art solutions all require negative feedback control and compensation, have high requirements for the feedback control of the excitation source, and have high requirements for the duty cycle of the excitation signal.

[0029] like Figure 3 The figure shows a schematic diagram of the hysteresis loop of a ferromagnetic material in different saturation states. In the prior art, when leakage detection is performed based on magnetic induction intensity, the prior art usually performs detection based on the hysteresis loop being in the critical saturation state, and applies the measured current. After that, both 'vertices' of the 'critical saturation' hysteresis loop will change: one side moves towards the 'supersaturation' region, so B unchanged; one side moves towards the 'unsaturated' region, B The absolute value of the curve decreases. B The value will change, which can be measured by B Or something with B The relevant amount, according to The measured current is derived from the curve , critical saturation modulation requires that both vertices of the hysteresis loop be exactly at the saturation point. Due to individual differences between devices, there are high requirements for production calibration.

[0030] To avoid the above situation, the present application provides a leakage detection device and method based on half-saturation magnetic induction intensity. The leakage detection device based on half-saturation magnetic induction intensity is as follows: Figure 2 As shown, the current to be measured only needs to pass through the magnetic core. The device includes:

[0031] Excitation signal module, configuration resistor, excitation coil, magnetic core, integration circuit and signal processing module, wherein:

[0032] The excitation coil is wound on the magnetic core, and both ends of the excitation coil are connected to the excitation signal module and the integration circuit. One end of the excitation coil is connected to the excitation signal module with the configuration resistor arranged in the middle, and the integration circuit is connected to the signal processing module.

[0033] Among them, the integration circuit is specifically used to obtain the back electromotive force of the excitation coil and integrate it to obtain a waveform signal, and the signal processing module is specifically used to extract the peak-to-peak value from the waveform signal and determine the actual current value of the current to be measured according to a preset corresponding table.

[0034] The half-saturation hysteresis loop is Figure 4 As shown in the figure and the following description The horizontal axis H , which represents the core B and H , that is, the magnetic field strength formed by the excitation current and the measured current. If you want to obtain the excitation signal on the magnetic core Curve (i.e., measurable Curve), the Shift the measured current on the horizontal axis Create a magnetic field strength and apply the measured current After that, similar to critical saturation, the two 'vertices' of the hysteresis loop will change: one side moves to the 'supersaturation' region, so B unchanged; while moving in the 'unsaturated' region, B The absolute value of increases, the semi-saturation modulation has a range requirement for the two vertices of the hysteresis loop, as long as it is within the specified range. One of the vertices is in the oversaturation region (positive peak value of the excitation current). Scope Requirements ), and the other vertex is Nearby, that is, within a specified interval centered on 0, the specified interval can be set by a person skilled in the art according to actual conditions. Therefore, there is greater "fault tolerance" for the excitation source and low requirements for production calibration.

[0035] In order to better apply the device, the present application provides a leakage detection method based on semi-saturated magnetic induction. Figure 1 As shown, applied to the device as described above, the method includes:

[0036] Step S101, placing a magnetic core at a preset distance from a current to be measured, sending an excitation signal to an excitation coil on the magnetic core through an excitation signal module, and converting the excitation signal into an asymmetric alternating current with positive and negative currents through configuring a resistor.

[0037] Specifically, before sending the excitation signal to the excitation coil through the excitation signal module, the method further includes determining the saturation magnetic induction intensity of the magnetic core, the minimum saturation current for the magnetic core to reach saturation, the number of turns of the excitation coil and the resistance value of the configuration resistor according to the attribute information of the magnetic core. The saturation magnetic induction intensity can be queried through the magnetic core specification. , the number of coil turns is N, the configuration resistor is R, and the saturation excitation voltage is , is a constant, is the core characteristic value, is a variable, then the saturation magnetic induction current According to this formula and the actual working conditions, the saturation excitation current can be obtained . Peak excitation current Should satisfy , The configuration resistor can be a common resistor. The positive peak value of the alternating current can make the magnetic induction intensity of the magnetic core reach saturation, and the negative peak value of the alternating current can make the magnetic induction intensity value of the magnetic core zero. That is to say, the excitation signal module and current configuration resistors R Connect the excitation coil N , generating positive and negative asymmetrical alternating current, the positive and negative peak values ​​of the alternating current , Make the magnetic induction intensity of the magnetic core reach and In the specified interval centered at 0.

[0038] Step S102: acquiring the back electromotive force generated by the excitation coil, and integrating the back electromotive force through an integration circuit to obtain a waveform signal.

[0039] In the embodiment of the present application, due to the back electromotive force of the coil

[0040] ,

[0041] Therefore, the change in the average value of B within the core cross section S is

[0042] ,

[0043] So the coil back EMF can be used Points To represent the magnetic induction intensity B, so the back electromotive force Integrated peak-to-peak value It can represent the peak-to-peak value of the magnetic induction intensity B , and the BH hysteresis loop changes very little when it reaches magnetic saturation, so it can be and Corresponding. And because , you can With the measured current correspond.

[0044] Direct detection in the prior art, such as 'peak', 'duty cycle', 'time' and other detections, are all detections of a fixed point (voltage at a fixed time point, or time at a fixed voltage point). It can only reflect the change of a point, so the change is very small, and because the signal is very small, the anti-interference ability is very poor. This application uses integral detection, because it accumulates the signal of half a cycle, it can reflect the measured current All the cumulative changes caused by this, so the change amount is large and the anti-interference ability is strong.

[0045] Step S103: extracting the peak-to-peak value from the waveform signal through a signal processing module, and determining the actual current value of the current to be measured according to a preset corresponding table.

[0046] Specifically, the excitation signal module , Configuration resistor R and excitation coil N Used to modulate the magnetic induction intensity of the magnetic core. The magnetic core is used to convert the current passing through the magnetic core into magnetic induction intensity and feed it back to the excitation coil. Integrator circuit and signal processing modules It is used to convert the back electromotive force on the exciting coil into the external current to be measured. Integrated peak-to-peak value With the measured current But the back EMF The integrated waveform is a periodic alternating waveform, and the peak-to-peak value observation is not intuitive. After the peak-to-peak value is latched, it can be intuitively obtained The waveform of the measured current is Peak-to-peak value and real-time external current being measured There is a one-to-one correspondence, and the real-time measured external current can be obtained through the correspondence table The value of .

[0047] Step S104: determining whether leakage occurs in the current to be measured according to the actual current value of the current to be measured and the allowable operating range of the current to be measured.

[0048] Specifically, a comparison is made between the actual current value and the allowable operating range of the current to be measured. If the actual current value is not within the allowable operating range, it indicates that leakage has occurred in the current to be measured.

[0049] Based on the above-mentioned leakage detection method based on half-saturated magnetic induction intensity, one or more embodiments of this specification also provide a platform and terminal for leakage detection based on half-saturated magnetic induction intensity. The platform or terminal may include a device, software, module, plug-in, server, client, etc. using the method described in the embodiments of this specification and combined with the necessary implementation hardware. Based on the same innovative concept, the system in one or more embodiments provided in the embodiments of this specification is as described in the following embodiments. Since the implementation scheme and method for solving the problem of the system are similar, the implementation of the specific system in the embodiments of this specification can refer to the implementation of the aforementioned method, and the repetitions will not be repeated. The terms "unit" or "module" used below can be a combination of software and / or hardware that implements the predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware, and the combination of software and hardware are also possible and conceived.

[0050] It should be noted that the above-mentioned system may also include other implementations according to the description of the corresponding method embodiment. Specifically, the above-mentioned specific embodiments of this specification are described. Other embodiments are within the scope of the attached claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiment and still achieve the desired results. In addition, the process depicted in the accompanying drawings does not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0051] The device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. There may be other divisions in actual implementation, such as multiple units or plug-ins may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be through some interface, indirect coupling or communication connection of the device or unit, which may be electrical, mechanical or other forms.

[0052] These computer program instructions may also be loaded onto a computer or other programmable resource data updating device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions executed on the computer or other programmable device for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0053] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. In the description of this specification, the description of the reference term "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0054] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A leakage detection method based on half-saturation magnetic induction intensity, characterized in that: The method comprises: The magnetic core is placed at a preset distance from the current to be measured, an excitation signal is sent to the excitation coil on the magnetic core through an excitation signal module, and the excitation signal is transformed into an asymmetric positive and negative alternating current through a configured resistor; Acquire the back electromotive force generated by the excitation coil, and integrate the back electromotive force through an integration circuit to obtain a waveform signal; Extracting the peak-to-peak value from the waveform signal through a signal processing module, and determining the actual current value of the current to be measured according to a preset corresponding table; Determining whether leakage occurs in the current to be measured according to the actual current value of the current to be measured and the allowable working range of the current to be measured; Among them, before sending an excitation signal to the excitation coil through the excitation signal module, the method also includes determining the saturation magnetic induction intensity of the magnetic core, the minimum saturation current for the magnetic core to reach saturation, the number of turns of the excitation coil and the resistance value of the configuration resistor according to the property information of the magnetic core, the positive peak value of the alternating current can make the magnetic induction intensity of the magnetic core reach saturation, and the negative peak value of the alternating current can make the magnetic induction intensity value of the magnetic core zero.

2. The leakage detection method based on half-saturation magnetic induction intensity as claimed in claim 1, characterized in that: The integral processing is specifically determined by the following formula: ， In the formula, B is the magnetic induction intensity of the excitation coil, is the back electromotive force, S is the core cross section, is the microvariable at time t.

3. A leakage detection device based on half-saturation magnetic induction intensity, characterized in that: Using a leakage detection method based on semi-saturated magnetic induction intensity as claimed in claim 1 or 2, the device includes an excitation signal module, a configuration resistor, an excitation coil, a magnetic core, an integration circuit and a signal processing module, wherein: The excitation coil is wound on the magnetic core, and both ends of the excitation coil are connected to the excitation signal module and the integration circuit, one end of the excitation coil is connected to the excitation signal module with the configuration resistor arranged in the middle, and the integration circuit is connected to the signal processing module; Among them, the integration circuit is specifically used to obtain the back electromotive force of the excitation coil and integrate it to obtain a waveform signal, and the signal processing module is specifically used to extract the peak-to-peak value from the waveform signal and determine the actual current value of the current to be measured according to a preset corresponding table.

Images