Arc detection apparatus and method, power converter, photovoltaic system, and related product

Abstract

The present application relates to an arc detection apparatus and method, a power converter, a photovoltaic system, and a related product. The arc detection apparatus comprises a sensing module used to acquire an arc characteristic signal of a cable; a filtering circuit connected to the sensing module and used to perform filtering on the arc characteristic signal acquired by the sensing module; and a processor connected to the filtering circuit and used to adjust a filter band of the filtering circuit on the basis of parameter information of the cable and / or noise information of the environment in which the cable is located, and determine an arc detection result on the basis of the arc characteristic signal outputted by the filtering circuit after adjustment of the filter band. In this way, the accuracy of arc detection is improved.

Description

Arc detection devices and methods, power converters, photovoltaic systems and related products

[0001] This application claims priority to Chinese Patent Application No. 202411832363.1, filed on December 11, 2024, entitled "Arc Detection Device and Method, Power Converter, Photovoltaic System and Related Products", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of arc detection technology, and in particular to an arc detection device and method, a power converter, a photovoltaic system and related products. Background Technology

[0003] With the development of photovoltaic (PV) power generation technology, photovoltaic power generation systems (hereinafter referred to as PV systems) have been widely used. Currently, electric arcs frequently occur in PV systems. To reduce the serious damage caused by electric arcs, it is essential to perform arc detection on PV systems.

[0004] In response, related technologies detect electric arcs by extracting the time-domain signal of the alternating current generated on the corresponding cable when an electric arc occurs, and then performing Fast Fourier Transform (FFT) analysis on the extracted time-domain signal of the alternating current.

[0005] However, the generated AC current time-domain signal is easily affected (e.g., by interference) and changes, resulting in inaccurate AC current time-domain signals often extracted in related technologies, which in turn leads to inaccurate arc detection results. Summary of the Invention

[0006] Therefore, it is necessary to provide an arc detection device and method, a power converter, a photovoltaic system, and related products that can improve the accuracy of arc detection, addressing the aforementioned technical problems.

[0007] In a first aspect, embodiments of this application provide an arc detection device, the device comprising:

[0008] The sensing module is used to collect the arc characteristic signals of the cable;

[0009] A filtering circuit, connected to the sensing module, is used to filter the arc characteristic signal collected by the sensing module.

[0010] The processor, connected to the filtering circuit, is used to adjust the filter passband of the filtering circuit according to the parameter information of the cable and / or the noise information of the environment where the cable is located, and to determine the arc detection result based on the arc characteristic signal output by the filtering circuit after the filter passband adjustment.

[0011] In one embodiment, the filtering circuit includes a filter resistor module and a filter capacitor module;

[0012] The processor is configured to adjust the filter passband of the filter circuit by adjusting the equivalent resistance value of the filter resistor module and / or the equivalent capacitance value of the filter capacitor module.

[0013] In one embodiment, the filter resistor module includes at least one filter resistor unit;

[0014] The filter resistor unit includes a first filter resistor, a second filter resistor, and a first switch;

[0015] The first filter resistor and the second filter resistor are connected in parallel, and the first switch is connected in series in the branch where the first filter resistor is located; or, the first filter resistor and the second filter resistor are connected in series, and the first switch is connected in parallel with the first filter resistor; the processor is connected to the first switch and is used to control the working state of the first switch to adjust the equivalent resistance value of the filter resistor module.

[0016] In one embodiment, the filter resistor module includes at least one variable filter resistor;

[0017] The processor is connected to the resistance adjustment terminal of the variable filter resistor and is used to adjust the resistance value of the variable filter resistor through the resistance adjustment terminal, thereby adjusting the equivalent resistance value of the filter resistor module.

[0018] In one embodiment, the filter capacitor module includes at least one filter capacitor unit;

[0019] The filter capacitor unit includes a first filter capacitor, a second filter capacitor, and a second switch;

[0020] The first filter capacitor is connected in parallel with the second filter capacitor, and the second switch is connected in series in the branch where the first filter capacitor is located; or, the first filter capacitor is connected in series with the second filter capacitor, and the second switch is connected in parallel with the first filter capacitor; the processor is connected to the second switch and is used to control the working state of the second switch to adjust the equivalent capacitance value of the filter capacitor module.

[0021] In one embodiment, the filtering circuit includes a high-pass filter and a low-pass filter;

[0022] Both the high-pass filter and the low-pass filter include the filter resistor module and the filter capacitor module.

[0023] In one embodiment, the high-pass filter further includes a first operational amplifier;

[0024] The filter resistor module in the high-pass filter is connected to the positive input terminal of the first operational amplifier, the output terminal of the first operational amplifier, and the filter capacitor module in the high-pass filter.

[0025] The negative input terminal of the first operational amplifier is connected to reference ground.

[0026] In one embodiment, the low-pass filter further includes a second operational amplifier;

[0027] The filter capacitor module in the low-pass filter is connected to the positive input terminal of the second operational amplifier, the output terminal of the second operational amplifier, and the filter resistor module in the low-pass filter.

[0028] The negative input terminal of the second operational amplifier is connected to reference ground.

[0029] In one embodiment, the filter circuit further includes a gain resistor module;

[0030] The gain resistor module is connected to the processor;

[0031] The processor is also configured to adjust the equivalent resistance value of the gain resistor module to adjust the gain of the filter circuit.

[0032] In one embodiment, the gain resistor module includes at least one gain resistor unit;

[0033] The gain resistor unit includes a first gain resistor, a second gain resistor, and a third switch;

[0034] The first gain resistor and the second gain resistor are connected in parallel, and the third switch is connected in series in the branch where the first gain resistor is located; or, the first gain resistor and the second gain resistor are connected in series, and the third switch is connected in parallel with the first gain resistor; the processor is connected to the third switch and is used to control the working state of the third switch to adjust the equivalent resistance value of the gain resistor module.

[0035] In one embodiment, the filtering circuit includes a high-pass filter and a low-pass filter, both of which include the gain resistor module.

[0036] Secondly, embodiments of this application provide a power converter, which includes at least one arc detection device as described in the first aspect above.

[0037] Thirdly, embodiments of this application provide a photovoltaic system, which includes connecting cables for photovoltaic modules and an arc detection device as described in the first aspect above;

[0038] The arc detection device is used to detect arcs on the connecting cable.

[0039] Fourthly, embodiments of this application provide an arc detection method, applied to a processor in the arc detection device as described in the first aspect above, the method comprising:

[0040] Collect parameter information of the cable under test and / or noise information of the environment in which the cable is located;

[0041] Adjust the filter passband of the filter circuit in the arc detection device according to the parameter information of the cable to be tested and / or the noise information;

[0042] The arc detection result is determined based on the arc characteristic signal output by the filter circuit after the filter passband adjustment.

[0043] In one embodiment, adjusting the filter passband of the filter circuit in the arc detection device based on the parameter information of the cable to be tested and / or the noise information includes:

[0044] Based on the parameter information of the cable to be tested and the noise information, determine the target filter passband required for arc detection of the cable;

[0045] If the target filter passband does not match the current filter passband, a passband adjustment signal is generated based on the target filter passband.

[0046] The passband adjustment signal is sent to the filter circuit to instruct the filter circuit to adjust the filter passband to the target filter passband.

[0047] In one embodiment, after adjusting the filter passband of the filter circuit in the arc detection device according to the parameter information of the cable to be detected and / or the noise information, the method further includes:

[0048] Adjust the gain of the filter circuit in the arc detection device according to the parameter information of the cable to be tested and / or the noise information;

[0049] The arc detection result is determined based on the arc characteristic signal output by the gain-adjusted filter circuit.

[0050] Fifthly, embodiments of this application provide an arc detection device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the arc detection method as described in the fourth aspect.

[0051] In a sixth aspect, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the arc detection method as described in the fourth aspect.

[0052] In a seventh aspect, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the arc detection method as described in the fourth aspect.

[0053] The aforementioned arc detection device and method, power converter, photovoltaic system, and related products include a sensing module, a filtering circuit, and a processor connected in sequence. The sensing module is used to acquire arc characteristic signals from the corresponding cable, such as the time-domain signal of the alternating current generated on the cable when an arc occurs. The filtering circuit has a filter passband, such as a bandpass filter; the filtering circuit is used to filter the arc characteristic signals acquired by the sensing module, or in other words, to extract signals within the filter passband of the filtering circuit from the arc characteristic signals acquired by the sensing module.

[0054] The generated arc characteristic signal is easily affected by the cable parameters and / or the noise of the cable's environment. For example, signals in certain frequency bands of the arc characteristic signal are easily attenuated by the cable parameters. In this embodiment, the filter passband of the filter circuit is adjustable. The adjusted passband of the filter circuit is well adapted to and matched with the cable parameters and / or the noise of the cable's environment. The processor determines the arc detection result based on the arc characteristic signal extracted by the adjusted passband filter circuit. This embodiment thus considers the influence of cable parameters and / or the noise of the cable's environment on the arc characteristic signal during arc detection, improving the accuracy of the extracted arc characteristic signal and consequently enhancing the accuracy of arc detection. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 is a schematic diagram of the arc detection device in one embodiment;

[0057] Figure 2 is a schematic diagram of the circuit where the cable is located in one embodiment;

[0058] Figure 3 is a schematic diagram of the structure of the filter resistor unit in one embodiment;

[0059] Figure 4 is a schematic diagram of the structure of the filter capacitor unit in one embodiment;

[0060] Figure 5 is a schematic diagram of one embodiment of a high-pass filter;

[0061] Figure 6 is a second schematic diagram of the structure of a high-pass filter in one embodiment;

[0062] Figure 7 is a schematic diagram of one embodiment of a low-pass filter;

[0063] Figure 8 is a second schematic diagram of the structure of a low-pass filter in one embodiment. Detailed Implementation

[0064] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0066] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0067] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. Furthermore, in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if there is transmission of electrical signals or data between the connected objects.

[0068] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0069] In one exemplary embodiment, referring to FIG1, an arc detection device is provided, which includes a sensing module 10, a filtering circuit 20, and a processor 30.

[0070] The sensing module 10 is used to collect the arc characteristic signal on the cable.

[0071] Generally, compared to the absence of an arc, the presence of an arc means that the time-domain signals of different frequency bands of the alternating current on the cable become richer, and the amplitude of each frequency band of the corresponding spectral signal increases. For example, for a DC cable, the presence of a DC arc means that an AC current time-domain signal superimposed on the DC current of the DC cable is generated; similarly, for an AC cable, the presence of an AC arc means that an AC current time-domain signal superimposed on the AC current of the AC cable is generated. Accordingly, in the embodiments of this application, the arc characteristic signal is, for example, the AC current time-domain signal generated on the cable when an arc occurs.

[0072] Furthermore, the cable can be understood as the cable in the circuit where the arc characteristic signal is located. This circuit can be a direct current circuit or an alternating current circuit. The circuit can be a circuit in a photovoltaic system or a circuit in other power systems; it is understood that the photovoltaic system in this application embodiment is only an example of an application scenario for the arc detection device and is not intended to specifically limit the application scope of the arc detection device. The arc does not necessarily appear on the circuit cable; it may also appear at other electronic components in the circuit, for example, due to loose, aging, or poor contact of the terminals in the circuit causing an arc at the terminals. The location of the arc in the circuit is not necessarily limited to one place; there may be several locations.

[0073] Taking a photovoltaic (PV) system as an example, a PV system typically includes a PV inverter. Referring to Figure 2, the DC side of the PV inverter includes at least one input terminal. Each input terminal is connected to at least one PV module. When multiple PV modules are connected, they are connected to each other via terminal blocks. As shown in Figure 2, the DC side of the PV inverter has at least one input of a PV module, which can be considered as a loop. That is, the first input terminal and the two PV modules connected to the first input terminal form a loop. Regardless of whether an arc occurs at position A and / or position B in the loop, the arc detection device treats it as an equivalent position in the loop. The arc detection device's arc detection of the loop can be understood as the arc detection at the equivalent position. The arc detection method of the arc detection device in the loop is to first collect the arc characteristic signal generated on the cable in the loop in real time through the sensing module 10.

[0074] It should be understood that on the DC side of a photovoltaic inverter, one input terminal of the photovoltaic inverter can correspond to one arc detection device, or multiple input terminals can correspond to one arc detection device. In the case where multiple input terminals correspond to one arc detection device, the arc detection device may include a processor 30, a filter circuit 20, and multiple sensor modules 10. The processor 30 is connected to the filter circuit 20, and the filter circuit 20 is connected to each sensor module 10. Each input terminal corresponds to one sensor module 10. Each sensor module 10 can be connected to the filter circuit 20 through a gating circuit. The sensor module 10 selected is the one whose input terminal loop cable is being arc detected. The gating circuit can be a conventional gating circuit such as a multi-way selector switch.

[0075] In addition, the AC side of the photovoltaic inverter is usually connected to the power grid. The photovoltaic inverter and the power grid are connected through the three-phase lines r, s, and t. The sensing module 10 can collect the arc characteristic signals generated on the phase lines in real time. The arc characteristic signals generated on the three-phase lines r, s, and t generally have different characteristics, such as different amplitudes. The processor 30 can determine which phase line the arc characteristic signal collected by the sensing module 10 is generated on based on the amplitude of the arc characteristic signal, and thus determine which phase line the arc appears on.

[0076] It should be understood that either three arc detection devices can be used to detect arcs on the r, s, and t phase cables respectively, or a single arc detection device can be used to detect arcs on the r, s, and t phase cables. In the case where a single arc detection device detects arcs on the r, s, and t phase cables, the arc detection device may include a processor 30, a filter circuit 20, and three sensor modules 10. The processor 30 is connected to the filter circuit 20, and the filter circuit 20 is connected to each sensor module 10. One sensor module 10 is provided for each phase cable. Each sensor module 10 can be connected to the filter circuit 20 via a selection circuit. The sensor module 10 selected corresponds to the phase cable for arc detection.

[0077] This application does not impose specific limitations on the number of arc detection devices installed in a single photovoltaic system or even a single photovoltaic inverter, nor on the number of sensing modules 10 installed in the arc detection devices. Furthermore, the arc detection device can be installed independently of the photovoltaic inverter, either externally or integrated inside the photovoltaic inverter; this is not specifically limited.

[0078] The sensing module 10 may include an arcing transformer; a cable passes through the magnetic core of the arcing transformer, and the arcing transformer collects the arc characteristic signal on the cable; for example, the arcing transformer collects the multi-band AC current time domain signal on the cable in the circuit in real time, and transmits the collected arc characteristic signal to the filter circuit 20.

[0079] The filter circuit 20 is connected to the sensing module 10 and is used to filter the arc characteristic signal collected by the sensing module 10.

[0080] Similar to a bandpass filter, the filter circuit 20 has at least a filtering function and a corresponding filter passband. Thus, for the received signal, the signal within its filter passband is not attenuated, and the signal outside its filter passband is attenuated to an almost infinite degree.

[0081] The filter circuit 20 does not attenuate signals within the filter passband of the arc characteristic signal collected by the sensing module 10, while the attenuation of signals outside the filter passband is close to infinite. It can be understood that the filter circuit 20 can extract signals within the filter passband of the filter circuit 20 from the arc characteristic signal collected by the sensing module 10.

[0082] It should be noted that, through research by the inventors of this application, it has been found that the parameter information of the cable and / or the noise information of the environment in which the cable is located can affect the arc characteristic signal generated on the cable, causing the arc characteristic signal to change. In other words, the generated arc characteristic signal is easily affected by the parameter information of the cable and / or the noise information of the environment in which the cable is located and changes accordingly. For example, the signal in certain frequency bands of the arc characteristic signal is easily attenuated significantly by the parameter information of the cable, or directly interferes with the arc characteristic signal.

[0083] The cable parameter information includes, but is not limited to, the total length of the cable in the loop, the material of the cable, and the thickness of the cable; the noise information of the environment in which the cable is located includes, but is not limited to, the AC current time-domain noise on the cable in the scenario in which the cable is located in the loop, and the AC current time-domain noise caused by AC side (power grid side) load coupling.

[0084] For example, the varying total lengths of cables in different loops are particularly common in distributed photovoltaic power generation systems. For the high-frequency arc characteristic signal among the multi-band arc characteristic signals collected by the sensing module 10, when the total length of the loop cable is very long, the high-frequency arc characteristic signal will suffer significant loss, attenuation, and amplitude reduction along the loop cable. Conversely, when the total length of the loop cable is short, there is virtually no attenuation.

[0085] For example, before a load is connected to the AC side (grid side), there is basically no coupled noise on the DC side circuit cable. However, after the load is connected to the AC side, coupled noise appears on the DC side circuit cable. This noise is, for example, a time-domain oscillation signal of AC current in a certain frequency band, which directly interferes with the arc characteristic signal.

[0086] In this regard, in this embodiment of the application, the filter passband of the filter circuit 20 is adjustable. The processor 30 is connected to the filter circuit 20, and the processor 30 can adjust the filter passband of the filter circuit 20 according to the parameter information of the cable and / or the noise information of the environment where the cable is located. For example, the filter passband of the filter circuit 20 can be adjusted from [FL1, FH1] to [FL2, FH2], [FL1, FH2] or [FL2, FH1], where FL and FH are the low-pass cutoff frequency and the high-pass cutoff frequency, respectively. For example, on the frequency coordinate axis, FL > FH, and the filter passband of the filter circuit 20 is composed of the overlapping frequency bands of (0, FL) and [FH, +∞). FL1 and FL2 are different, and FH1 and FH2 are different.

[0087] The adjusted passband of the filter circuit 20 is well adapted to and matched with the cable parameters and / or the noise information of the cable's environment. For example, if the current passband of the filter circuit 20 is a high-frequency passband, but the processor 30 determines that the total cable length to the current loop is very long, the arc characteristic signal in the high-frequency band will be significantly attenuated, while the arc characteristic signal in the low-frequency band will attenuate relatively little. In this case, the processor 30 will adjust the passband of the filter circuit 20 from the current high-frequency passband to the low-frequency passband, so that the arc characteristic signal in the low-frequency band will reach the processor 30 without attenuation when passing through the filter circuit 20. In other words, by adjusting the passband of the filter circuit 20, This ensures that the filter circuit 20 can always accurately extract signals within its filter passband. However, if the filter passband of the filter circuit 20 cannot be adjusted from the current high-frequency filter passband to the low-frequency filter passband, the arc characteristic signal located in the high-frequency band will have already been significantly attenuated. Furthermore, the current high-frequency filter passband of the filter circuit 20 will prevent the arc characteristic signal located in the low-frequency band from reaching the processor 30. This will result in the arc characteristic signal received by the processor 30 being messy, scattered, and inaccurate, thus leading to inaccurate arc detection results from the processor 30.

[0088] It should also be noted that, through research by the inventors of this application, it has been discovered that related technologies use bandpass filters with fixed passbands (i.e., the filter passband cannot be adjusted) to extract signals within the passband from the AC current time-domain signal generated on the corresponding cable when an electric arc occurs, for use in FFT analysis. However, because the generated AC current time-domain signal is easily affected (e.g., by interference) and changes, the signals within the passband change (e.g., are attenuated). In other words, there are essentially no signals within the passband in the acquired AC current time-domain signal (because the signals within the passband are affected and attenuated, or are very few and weak). Therefore, bandpass filters with fixed passbands cannot extract signals within the passband from the acquired AC current time-domain signal. Consequently, the signals captured by bandpass filters with fixed passbands are not signals within the passband; what is extracted is a messy, scattered, and inaccurate signal. That is, the extracted AC current time-domain signal is inaccurate, resulting in inaccurate arc detection results.

[0089] In this regard, in this embodiment of the application, the processor 30 determines the arc detection result based on the arc characteristic signal output by the filter circuit 20 after the filter passband adjustment. In this way, the influence of cable parameter information and / or noise information of the cable environment on the arc characteristic signal is taken into account in the arc detection, so that the arc characteristic signal received by the processor 30 is accurate and reliable, thereby improving the accuracy of arc detection.

[0090] The parameter information of the cable can be pre-stored in the processor 30; or the processor 30 can obtain it through other peripheral circuits; or the processor 30 can obtain it using the sensing module 10 in the arc detection device.

[0091] Noise information about the environment where the cable is located can be obtained by the processor 30 through other peripheral circuits, or by the sensing module 10 in the arc detection device.

[0092] The peripheral circuits for obtaining cable parameter information and / or noise information of the environment where the cable is located are arbitrary, and the specific method for obtaining cable parameter information and noise information of the environment where the cable is located is not limited in the embodiments of this application.

[0093] Understandably, when using an arc detection device, the processor 30 can determine the target filter passband required for current cable arc detection based on the cable parameter information and / or the noise information of the cable's environment. Then, if the target filter passband is different from the current filter passband of the filter circuit 20, the filter passband of the filter circuit 20 is adjusted from the current filter passband to the target filter passband.

[0094] The following are not intended to limit the technical solutions of the embodiments of this application, but are merely illustrative examples for ease of understanding:

[0095] Example 1: Referring to Figure 2, suppose there is an arc detection device used to detect the arc in the first input loop cable of the DC side of the photovoltaic inverter. Then the sensing module 10 in the arc detection device can be set on the first input loop cable. The filter circuit 20 and the processor 30 can be integrated with the sensing module 10 on a circuit board. Alternatively, the filter circuit 20 and the processor can be set independently of the sensing module 10 and located inside or outside the photovoltaic inverter.

[0096] If the switching frequency of the photovoltaic inverter is a first frequency value, then when the photovoltaic inverter is working, the sensing module 10 can detect the AC current time-domain oscillation signal of the first frequency value on each input loop cable on the DC side, regardless of whether an electric arc occurs. The processor 30 can determine the total length of the first input loop cable based on the attenuation degree of the amplitude of the AC current time-domain oscillation signal of the first frequency value on the first input loop cable. Generally, the longer the total length, the greater the amplitude attenuation, and the shorter the total length, the less the amplitude attenuation. Then, the processor 30 adjusts the filter passband of the filter circuit 20 according to the total length so that the filter passband of the filter circuit 20 is adapted to the total length.

[0097] Meanwhile, if a load is connected to the AC side, the connection of the load will cause an AC current time-domain oscillation signal with a second frequency value on the first input terminal loop cable. This AC current time-domain oscillation signal with a second frequency value, as noise in the environment where the cable is located, will directly interfere with the arc characteristic signal. Therefore, the processor 30 can further adjust the filter passband of the filter circuit 20 according to the AC current time-domain oscillation signal with the second frequency value, so that the filter passband of the filter circuit 20 does not contain the second frequency value.

[0098] Example 2: Referring to Figure 2, suppose there is an arc detection device. This arc detection device is used to detect the arc in the first input loop cable and the second input loop cable of the DC side of the photovoltaic inverter. Then, the first sensing module 10 in the arc detection device can be set on the first input loop cable, and the second sensing module 10 can be set on the second input loop cable. The first sensing module 10 and the second sensing module 10 are connected to the filter circuit 20 through the first gating channel and the second gating channel, respectively.

[0099] When arc detection is required on the second input loop cable, the second selection channel is activated and the first selection channel is deactivated. The second sensing module 10 is connected to the filter circuit 20. The processor 30 adjusts the filter passband of the filter circuit 20 according to the total length of the second input loop cable, so that the filter passband is adapted to and matched with the total length of the second input loop cable. Specifically, the processor 30 can determine the total length of the second input loop cable based on the attenuation degree of the amplitude of the AC current time-domain oscillation signal with the first frequency value on the second input loop cable.

[0100] Alternatively, when arc detection is required on the second input loop cable, the second selection channel is opened and the first selection channel is closed. The second sensing module 10 is connected to the filter circuit 20. At this time, if a load is connected to the AC side, the connection of the load will cause an AC current time-domain oscillation signal with a third frequency value on the second input loop cable. The processor 30 can adjust the filter passband of the filter circuit 20 according to the AC current time-domain oscillation signal with the third frequency value so that the filter passband of the filter circuit 20 does not contain the third frequency value.

[0101] In Examples 1 and 2 above, the AC current time-domain oscillation signals at the first, second, and third frequencies can all be understood as noise signals on the DC-side cables, and can all be detected by the sensing module 10. The processor 30 can determine the total length of each input loop cable based on the amplitude attenuation of the AC current time-domain oscillation signal at the first frequency. Of course, the total length of each input loop cable can also be obtained in any other way and then pre-stored for direct application by the processor 30; the AC current time-domain noise caused by AC-side (grid-side) load coupling can also be obtained in any other way and transmitted to the processor 30 for direct application.

[0102] In this embodiment, the specific content on which the processor 30 adjusts the filter passband of the filter circuit 20 is based is not limited, nor is the method of obtaining the specific content limited. The specific content on which it is based may be, for example, the total length of the loop cable, various noises on the loop cable, other parameters of the loop cable, or other information or signals that affect or interfere with the arc characteristic signal. This triggers the processor 30 to adjust the filter passband of the filter circuit 20 so that the filter passband of the filter circuit 20 is well adapted to, matched and consistent with the current actual arc detection scenario. In short, the filter passband of the filter circuit 20 can be adjusted in real time so that the filter circuit 20 can accurately extract the arc characteristic signal used to determine whether an arc has occurred. All of these are inventive concepts of this embodiment and are within the protection scope of this invention.

[0103] The filter circuit provided in this application has various specific structures. Several of them are described below as examples, but they are not intended to limit the specific structure of the filter circuit.

[0104] In an exemplary embodiment, the filter circuit 20 includes a filter resistor module and a filter capacitor module; the processor 30 is used to adjust the filter passband of the filter circuit 20 by adjusting the equivalent resistance value of the filter resistor module and / or the equivalent capacitance value of the filter capacitor module.

[0105] In this embodiment, the specific value of the equivalent resistance of the filter resistor module in the filter circuit 20 can affect the specific size of the filter passband of the filter circuit 20, and the specific value of the equivalent capacitance of the filter capacitor module in the filter circuit 20 can also affect the specific size of the filter passband of the filter circuit 20. Therefore, the processor 30 can adjust the filter passband of the filter circuit 20 by adjusting the equivalent resistance value of the filter resistor module and / or the equivalent capacitance value of the filter capacitor module in the filter circuit 20.

[0106] For example, the filter circuit 20 may include, but is not limited to, a high-pass filter and a low-pass filter. The cutoff frequency of the high-pass filter may be used as the high-pass cutoff frequency FH ​​of the filter circuit 20, and the cutoff frequency of the low-pass filter may be used as the low-pass cutoff frequency FL of the filter circuit 20. The high-pass cutoff frequency FH ​​and the low-pass cutoff frequency FL of the filter circuit 20 constitute the filter passband of the filter circuit 20.

[0107] A high-pass filter includes a filter resistor module and a filter capacitor module, and / or a low-pass filter includes a filter resistor module and a filter capacitor module. The specific value of the equivalent resistance of the filter resistor module in the high-pass filter affects the specific value of the cutoff frequency of the high-pass filter, and the specific value of the equivalent capacitance of the filter capacitor module in the high-pass filter also affects the specific value of the cutoff frequency of the high-pass filter. Similarly, the specific value of the equivalent resistance of the filter resistor module and / or the equivalent capacitance of the filter capacitor module in the low-pass filter affects the specific value of the cutoff frequency of the low-pass filter. Therefore, the processor 30 can adjust the filter passband of the filter circuit 20 by adjusting the equivalent resistance value of the filter resistor module and / or the equivalent capacitance value of the filter capacitor module in the high-pass filter and / or the low-pass filter.

[0108] A filter resistor module consists of multiple resistors, and a filter capacitor module consists of multiple capacitors. The specific structure of the filter resistor module in a high-pass filter can be the same as or different from that in a low-pass filter. The specific structure includes the number of resistors and / or the connection relationships between them. Similarly, the specific structure of the filter capacitor module in a high-pass filter can be the same as or different from that in a low-pass filter. The specific structure includes the number of capacitors and / or the connection relationships between them. Furthermore, when both a high-pass and low-pass filter include filter resistor and filter capacitor modules, the specific connection relationships between the filter resistor and filter capacitor modules in the high-pass filter and the low-pass filter can be different.

[0109] In an exemplary embodiment, the filter resistor module includes at least one filter resistor unit. Referring to FIG3, the filter resistor unit includes a first filter resistor R1, a second filter resistor R2, and a first switch K2. The first filter resistor R1 and the second filter resistor R2 are connected in parallel, and the first switch K2 is connected in series in the branch where the first filter resistor R1 is located. The processor 30 is connected to the first switch K2 and is used to control the working state of the first switch K2 to adjust the equivalent resistance value of the filter resistor unit, thereby adjusting the equivalent resistance value of the filter resistor module.

[0110] Alternatively, the filter resistor unit includes a first filter resistor R1, a second filter resistor R2, and a first switch K2; the first filter resistor R1 and the second filter resistor R2 are connected in series, and the first switch K2 and the first filter resistor R2 are connected in parallel; the processor 30 is connected to the first switch K2 and is used to control the working state of the first switch K2 to adjust the equivalent resistance value of the filter resistor unit, thereby adjusting the equivalent resistance value of the filter resistor module.

[0111] In this embodiment, the filter resistor module includes at least one filter resistor unit, wherein the specific magnitude of the equivalent resistance value of each filter resistor unit can affect the specific magnitude of the equivalent resistance value of the filter resistor module. This embodiment does not specifically limit the number of filter resistor units in the filter resistor module, nor does it specifically limit the connection relationship between the filter resistor units in the filter resistor module.

[0112] A filter resistor unit is constructed, comprising at least one first switch K2 and at least two filter resistors (i.e., first filter resistor R1 and second filter resistor R2), and the filter resistor module includes the at least one filter resistor unit. Thus, the processor 30 can adjust the number of filter resistors contributing to the equivalent resistance value of the filter resistor unit, or adjust the specific structure of the filter resistor unit, by controlling the on or off state of each first switch K2, thereby adjusting the equivalent resistance value of the filter resistor unit to achieve the adjustment of the equivalent resistance value of the filter resistor module.

[0113] Understandably, the significance of constructing the filter resistor unit lies in the fact that by controlling the on / off state of the first switch K2 in the filter resistor unit, the equivalent resistance value of the filter resistor unit can be adjusted. The equivalent resistance value of the filter resistor unit contributes to the equivalent resistance value of the filter resistor module, meaning that the specific magnitude of the equivalent resistance value of the filter resistor unit can affect the equivalent resistance value of the filter resistor module. This makes the equivalent resistance value of the filter resistor module adjustable. Furthermore, the specific values ​​of the low-pass cutoff frequency FL and / or high-pass cutoff frequency FH ​​of the filter circuit 20 are related to the equivalent resistance value of the filter resistor module, thus making the low-pass cutoff frequency FL and / or high-pass cutoff frequency FH ​​of the filter circuit 20 adjustable, and consequently, the filter passband of the filter circuit 20 adjustable.

[0114] Furthermore, Figure 3 is merely an example of the structure of a filter resistor unit and is not a specific limitation on the filter resistor unit. For example, in other embodiments, the filter resistor unit may include multiple first switches K2 and more filter resistors R. The connection relationships between these multiple first switches K2 and more filter resistors R are also diverse, all of which fall within the protection scope of this application. By controlling the on / off state of each first switch K2, the equivalent resistance value of the filter resistor unit can be adjusted, thereby making the equivalent resistance value of the filter resistor module adjustable and ensuring the adjustable filter passband characteristics of the filter circuit 20. When the filter resistor module includes multiple filter resistor units, the connection relationships between these multiple filter resistor units are also arbitrary, as long as the filtering function of the filter circuit 20 is achieved while ensuring the adjustable filter passband characteristics of the filter circuit 20.

[0115] In one exemplary embodiment, the filter resistor module includes at least one variable filter resistor; the processor 30 is connected to the resistance adjustment terminal of the variable filter resistor and is used to adjust the resistance value of the variable filter resistor through the resistance adjustment terminal to adjust the equivalent resistance value of the filter resistor module.

[0116] For example, the variable filter resistor is a sliding resistor, and the resistance adjustment terminal of each sliding resistor in the filter resistor module is connected to the processor 30.

[0117] In this embodiment, the filter resistor module includes at least one variable filter resistor, so that the processor 30 can adjust the equivalent resistance value of the filter resistor module by controlling the resistance value of each variable filter resistor.

[0118] In an exemplary embodiment, the filter capacitor module includes at least one filter capacitor unit. Referring to FIG4, the filter capacitor unit includes a first filter capacitor C1, a second filter capacitor C2, and a second switch K1. The first filter capacitor C1 and the second filter capacitor C2 are connected in parallel, and the second switch K1 is connected in series in the branch where the first filter capacitor C1 is located. The processor 30 is connected to the second switch K1 and is used to control the working state of the second switch K1 to adjust the equivalent capacitance value of the filter capacitor unit, thereby adjusting the equivalent capacitance value of the filter capacitor module.

[0119] Alternatively, the filter capacitor unit includes a first filter capacitor C1, a second filter capacitor C2, and a second switch K1. The first filter capacitor C1 and the second filter capacitor C2 are connected in series, and the second switch K1 is connected in parallel with the first filter capacitor C1. The processor 30 is connected to the second switch K1 and is used to control the working state of the second switch K1 to adjust the equivalent capacitance value of the filter capacitor unit, thereby adjusting the equivalent capacitance value of the filter capacitor module.

[0120] In this embodiment, the filter capacitor module includes at least one filter capacitor unit, wherein the specific size of the equivalent capacitance value of each filter capacitor unit can affect the specific size of the equivalent capacitance value of the filter capacitor module. This embodiment does not specifically limit the number of filter capacitor units in the filter capacitor module, nor does it specifically limit the connection relationship between the filter capacitor units in the filter capacitor module.

[0121] A filter capacitor unit is constructed, comprising at least one second switch K1 and at least two filter capacitors (i.e., the first filter capacitor C1 and the second filter capacitor C2), and the filter capacitor module includes the at least one filter capacitor unit. Thus, the processor 30 can adjust the number of filter capacitors contributing to the equivalent capacitance value of the filter capacitor unit, or adjust the specific structure of the filter capacitor unit, by controlling the on or off state of each second switch K1, thereby adjusting the equivalent capacitance value of the filter capacitor unit and thus achieving the adjustment of the equivalent capacitance value of the filter capacitor module.

[0122] Understandably, the significance of constructing the filter capacitor unit lies in the fact that, by controlling the on / off state of the second switch K1 in the filter capacitor unit, the equivalent capacitance value of the filter capacitor unit can be adjusted. The equivalent capacitance value of the filter capacitor unit contributes to the equivalent capacitance value of the filter capacitor module; that is, the specific magnitude of the equivalent capacitance value of the filter capacitor unit can affect the equivalent capacitance value of the filter capacitor module. This allows the equivalent capacitance value of the filter capacitor module to be adjusted. Furthermore, the specific values ​​of the low-pass cutoff frequency FL and / or high-pass cutoff frequency FH ​​of the filter circuit 20 are both related to the equivalent capacitance value of the filter capacitor module, thus allowing the low-pass cutoff frequency FL and / or high-pass cutoff frequency FH ​​of the filter circuit 20 to be adjusted, and consequently, allowing the filter passband of the filter circuit 20 to be adjusted.

[0123] Furthermore, Figure 4 is merely an example of the structure of a filter capacitor unit and is not intended to limit its specific implementation. For instance, in other embodiments, the filter capacitor unit may include multiple second switches K1 and more filter capacitors C. The connection relationships between these multiple second switches K1 and more filter capacitors C are also diverse, all of which fall within the protection scope of this application. By controlling the on / off state of each second switch K1, the equivalent capacitance value of the filter capacitor unit can be adjusted, thereby making the equivalent capacitance value of the filter capacitor module adjustable and ensuring the adjustable filter passband characteristics of the filter circuit 20. When the filter capacitor module includes multiple filter capacitor units, the connection relationships between these multiple filter capacitor units are also arbitrary, as long as the filtering function of the filter circuit 20 is achieved while ensuring the adjustable filter passband characteristics of the filter circuit 20.

[0124] In one exemplary embodiment, the filter circuit 20 includes a high-pass filter and a low-pass filter. The high-pass filter includes a filter resistor module and a filter capacitor module, and the low-pass filter includes a filter resistor module and a filter capacitor module.

[0125] In this embodiment, the high-pass filter can be connected to the low-pass filter. The cutoff frequency of the high-pass filter and the cutoff frequency of the low-pass filter constitute the filter passband of the filter circuit 20. The processor 30 can adjust the cutoff frequency of the high-pass filter by adjusting the equivalent resistance value of the filter resistor module and / or the equivalent capacitance value of the filter capacitor module in the high-pass filter. It can also adjust the cutoff frequency of the low-pass filter by adjusting the equivalent resistance value of the filter resistor module and / or the equivalent capacitance value of the filter capacitor module in the low-pass filter. The processor 30 adjusts the filter passband of the filter circuit 20 by adjusting the cutoff frequency of the high-pass filter and / or the cutoff frequency of the low-pass filter.

[0126] For high-pass and / or low-pass filters: the filter resistor module can be composed of multiple individual resistors, multiple pre-constructed filter resistor units, or at least one individual resistor and at least one pre-constructed filter resistor unit; that is, it can be composed of any number of individual resistors, any number of filter resistor units, or any combination of any number of individual resistors and any number of filter resistor units. Similarly, the filter capacitor module can be composed of multiple individual capacitors, multiple pre-constructed filter capacitor units, or at least one individual capacitor and at least one pre-constructed filter capacitor unit; that is, it can be composed of any number of individual capacitors, any number of filter capacitor units, or any combination of any number of individual capacitors and any number of filter capacitor units. The inclusion of filter resistor units and filter capacitor units is to adjust the equivalent resistance value of the filter resistor module and the equivalent capacitance value of the filter capacitor module, thereby adjusting the filter passband of the filter circuit 20.

[0127] In an exemplary embodiment, referring to FIG5, the high-pass filter further includes a first operational amplifier 47. The filter resistor module in the high-pass filter is connected to the positive input terminal of the first operational amplifier 47, the output terminal of the first operational amplifier 47, and the filter capacitor module in the high-pass filter; the negative input terminal of the first operational amplifier 47 is connected to reference ground.

[0128] Figure 5 illustrates an exemplary high-pass filter, which includes a first operational amplifier 47, two filter capacitor units 41 and 42, and two resistors 43 and 44. Specifically, the filter capacitor module of this high-pass filter includes two filter capacitor units 41 and 42, each of which includes a second switch K1 and two filter capacitors C1 and C2; the filter resistor module of this high-pass filter includes two resistors 43 and 44. Furthermore, the exemplary high-pass filter illustrated in Figure 5 is a Sallen-Key high-pass filter. In its cutoff frequency calculation formula, the cutoff frequency is negatively correlated with a product. This product is the product of the equivalent capacitance of filter capacitor unit 41, the equivalent capacitance of filter capacitor unit 42, the resistance of resistor 43, and the resistance of resistor 44. In other words, increasing (decreasing) at least one of these four values ​​will correspondingly decrease (increase) the cutoff frequency of the high-pass filter, and the change in the cutoff frequency of the high-pass filter will change the filter passband of the filter circuit 20.

[0129] For example, continuing to refer to Figure 5, the processor 30 can adjust the equivalent capacitance value of the filter capacitor units 41 and 42 by controlling the on or off of the second switches K1-1 and K1-2, which can also adjust the equivalent capacitance value of the filter capacitor module in the high-pass filter; and, when the resistors 43 and 44 are both sliding resistors, the processor 30 can also adjust the equivalent resistance value of the filter resistor module in the high-pass filter by adjusting the resistance values ​​of the resistors 43 and 44.

[0130] In an exemplary embodiment, referring to FIG6, the high-pass filter illustrated in FIG6 includes a first operational amplifier 47, two filter capacitor units 41 and 42, a filter resistor unit 51, and a resistor 44. That is, the filter capacitor module of the high-pass filter includes two filter capacitor units 41 and 42, and each of the two filter capacitor units 41 and 42 includes a second switch K1 and two filter capacitors C1 and C2; the filter resistor module of the high-pass filter includes a filter resistor unit 51 and a resistor 44, and the filter resistor unit 51 includes a first switch K2 and two filter resistors R1 and R2. Furthermore, the high-pass filter illustrated in Figure 6 is also a Sallen-Key high-pass filter. In the formula for calculating its cutoff frequency, the cutoff frequency is negatively correlated with a product. This product is the product of the equivalent capacitance value of filter capacitor unit 41, the equivalent capacitance value of filter capacitor unit 42, the equivalent resistance value of filter resistor unit 51, and the resistance value of resistor 44. In other words, increasing (decreasing) at least one of these four values ​​will correspondingly decrease (increase) the cutoff frequency of the high-pass filter. And when the cutoff frequency of the high-pass filter changes, the filter passband of filter circuit 20 changes.

[0131] For example, continuing to refer to Figure 6, the processor 30 can adjust the equivalent capacitance values ​​of the filter capacitor units 41 and 42 by controlling the on or off state of the second switches K1-1 and K1-2, which also adjusts the equivalent capacitance value of the filter capacitor module in the high-pass filter; the processor 30 can adjust the equivalent resistance value of the filter resistor unit 51 by controlling the on or off state of the first switch K2-1, which also adjusts the equivalent resistance value of the filter resistor module in the high-pass filter; and, when the resistor 44 is a sliding resistor, the processor 30 can also adjust the equivalent resistance value of the filter resistor module in the high-pass filter by adjusting the resistance value of the resistor 44.

[0132] In an exemplary embodiment, referring to FIG7, the low-pass filter further includes a second operational amplifier 57. The filter capacitor module in the low-pass filter is connected to the positive input terminal, the output terminal of the second operational amplifier 57, and the filter resistor module in the low-pass filter; the negative input terminal of the second operational amplifier 57 is connected to reference ground.

[0133] Figure 7 illustrates an exemplary low-pass filter, which includes a second operational amplifier 57, two filter resistor units 51 and 52, and two capacitors 53 and 54. Specifically, the filter resistor module of the low-pass filter includes two filter resistor units 51 and 52, each of which includes a first switch K2 and two filter resistors R1 and R2; the filter capacitor module of the low-pass filter includes two capacitors 53 and 54. Furthermore, the low-pass filter illustrated in Figure 7 is a Sallen-Key low-pass filter. In its cutoff frequency calculation formula, the cutoff frequency is negatively correlated with a product. This product is the product of the equivalent resistance value of filter resistor unit 51, the equivalent resistance value of filter resistor unit 52, the capacitance value of capacitor 53, and the capacitance value of capacitor 54. In other words, increasing (decreasing) at least one of these four values ​​will correspondingly decrease (increase) the cutoff frequency of the low-pass filter, and the change in the cutoff frequency of the low-pass filter will change the filter passband of the filter circuit 20.

[0134] For example, continuing to refer to Figure 7, the processor 30 can adjust the equivalent resistance values ​​of the filter resistor units 51 and 52 by controlling the first switches K2-1 and K2-2 to turn them on or off, which in turn can also adjust the equivalent resistance value of the filter resistor module in the low-pass filter.

[0135] In an exemplary embodiment, referring to FIG8, the low-pass filter illustrated in FIG8 includes a second operational amplifier 57, two filter resistor units 51 and 52, and two filter capacitor units 41 and 42. That is, the filter resistor module of the low-pass filter includes two filter resistor units 51 and 52, and each of the two filter resistor units 51 and 52 includes a first switch K2 and two filter resistors R1 and R2; the filter capacitor module of the low-pass filter includes two filter capacitor units 41 and 42, and each of the two filter capacitor units 41 and 42 includes a second switch K1 and two filter capacitors C1 and C2. Furthermore, the low-pass filter illustrated in Figure 8 is a Sallen-Key low-pass filter. In the formula for calculating its cutoff frequency, the cutoff frequency is negatively correlated with a product. This product is the product of the equivalent resistance value of filter resistor unit 51, the equivalent resistance value of filter resistor unit 52, the equivalent capacitance value of filter capacitor unit 41, and the equivalent capacitance value of filter capacitor unit 42. In other words, increasing (decreasing) at least one of these four values ​​will correspondingly decrease (increase) the cutoff frequency of the low-pass filter. And when the cutoff frequency of the low-pass filter changes, the filter passband of the filter circuit 20 changes.

[0136] For example, continuing to refer to Figure 8, the processor 30 can adjust the equivalent resistance values ​​of the filter resistor units 51 and 52 by controlling the first switches K2-1 and K2-2 to turn them on or off, which also adjusts the equivalent resistance value of the filter resistor module in the low-pass filter; the processor 30 can also adjust the equivalent capacitance values ​​of the filter capacitor units 41 and 42 by controlling the second switches K1-1 and K1-2 to turn them on or off, which also adjusts the equivalent capacitance value of the filter capacitor module in the low-pass filter.

[0137] It is understandable that resistor 44 in Figure 5 can also be set as a filter resistor unit according to actual needs, and filter capacitor units 41 and 42 in Figure 5 can each be set as a single capacitor according to actual needs, and filter resistor units 51 and 52 in Figure 7 can each be set as a single resistor according to actual needs.

[0138] In other words, in this embodiment, the filter resistor module in the filter circuit 20 may include all resistors in the filter circuit 20 that contribute to the specific size of the filter passband of the filter circuit 20; the filter resistor module in the high-pass filter may include all resistors in the high-pass filter that contribute to the specific size of the cutoff frequency of the high-pass filter; and the filter resistor module in the low-pass filter may include all resistors in the low-pass filter that contribute to the specific size of the cutoff frequency of the low-pass filter. Any resistor in the filter resistor module can be set as a single resistor device or as a filter resistor unit, depending on the actual needs. Figures 5 to 8 are merely examples and are not intended to limit the specific structure of each filter resistor module in the filter circuit 20. Furthermore, in this embodiment, the number of filter resistor modules and filter resistor units in the filter circuit 20 are not specifically limited, nor is the specific structure of the filter resistor units specifically limited, as long as the filter passband of the filter circuit 20 can be adjusted by adjusting their equivalent resistance value.

[0139] Similarly, in this embodiment, the filter capacitor module in the filter circuit 20 may include all capacitors in the filter circuit 20 that contribute to the specific size of the filter passband of the filter circuit 20. The filter capacitor module in the high-pass filter may include all capacitors in the high-pass filter that contribute to the specific size of the cutoff frequency of the high-pass filter. The filter capacitor module in the low-pass filter may include all capacitors in the low-pass filter that contribute to the specific size of the cutoff frequency of the low-pass filter. Any capacitor in the filter capacitor module can be set as a single capacitor or as a filter capacitor unit. These can be set according to the actual needs. Figures 5 to 8 are only examples and are not intended to limit the specific structure of each filter capacitor module in the filter circuit 20. In addition, in this embodiment, the number of filter capacitor modules and the number of filter capacitor units in the filter circuit 20 are not specifically limited, nor is the specific structure of the filter capacitor units specifically limited, as long as the filter passband of the filter circuit 20 can be adjusted by adjusting its equivalent capacitance value.

[0140] In one exemplary embodiment, the filter circuit 20 further includes a gain resistor module; the gain resistor module is connected to the processor 30; the processor 30 is also configured to adjust the equivalent resistance value of the gain resistor module to adjust the gain of the filter circuit.

[0141] In one exemplary embodiment, the filtering circuit includes a high-pass filter and a low-pass filter, both of which include a gain resistor module.

[0142] In an exemplary embodiment, referring to FIG5 or FIG7, the gain resistor module includes at least one gain resistor unit 45 or gain resistor unit 55. The gain resistor unit includes a first gain resistor R3, a second gain resistor R4 and a third switch K3. The first gain resistor R3 and the second gain resistor R4 are connected in parallel, and the third switch K3 is connected in series in the branch where the first gain resistor R3 is located. The processor 30 is connected to the third switch K3 and is used to control the working state of the third switch K3 to adjust the equivalent resistance value of the gain resistor module.

[0143] Alternatively, the first gain resistor R3 and the second gain resistor R4 are connected in series, the third switch K3 is connected in parallel with the first gain resistor R3, and the processor 30 is connected to the third switch K3 to control the working state of the third switch K3 in order to adjust the equivalent resistance value of the gain resistor module.

[0144] In Figures 5 and 6, the gain resistor module is illustrated by way of example, including a gain resistor unit 45 and a resistor 46. The specific gain of the high-pass filter is related to the equivalent resistance value of the gain resistor unit 45 and the resistance value of the resistor 46. In Figures 7 and 8, the gain resistor module is illustrated by way of example, including a gain resistor unit 55 and a resistor 56. The specific gain of the low-pass filter is related to the equivalent resistance value of the gain resistor unit 55 and the resistance value of the resistor 56. Of course, the resistor 46 and / or the resistor 56 can be an adjustable resistor, such as a sliding resistor, or it can be in the form of a gain resistor unit. This embodiment does not specifically limit this.

[0145] In one exemplary embodiment, the negative input terminal of the second operational amplifier 57 is connected to reference ground via resistor 56, and the negative input terminal of the first operational amplifier 47 is connected to reference ground via resistor 46.

[0146] The gain resistor module in a high-pass filter can include all resistors that contribute to the specific magnitude of the gain of the high-pass filter. Similarly, the gain resistor module in a low-pass filter can include all resistors that contribute to the specific magnitude of the gain of the low-pass filter. Any resistor in the gain resistor module can be set as a single resistor device or as a gain resistor unit, depending on the specific needs of the application.

[0147] In this embodiment, by setting the gain resistor module to include a gain resistor unit, the gain (i.e., amplification factor) of the filter resistor 20 can also be adjusted. Specifically, it can be achieved by adjusting the equivalent resistance value of the gain resistor module through the processor according to actual needs. The gain of the filter circuit 20 can be understood as the ratio of the amplitude of the output signal Vout of the filter circuit to the amplitude of the input signal Vin. The gain of the filter circuit 20 is an important parameter for measuring the amplification capability of the filter circuit 20.

[0148] In one exemplary embodiment, this application also provides a power converter that integrates at least one arc detection device as provided in any of the above embodiments.

[0149] The power converter and arc detection device provided in the embodiments of this application belong to the same inventive concept, can solve the same technical problem, and thus achieve the same technical effect. Repeated content will not be repeated here.

[0150] In one exemplary embodiment, this application also provides a photovoltaic system, which includes photovoltaic modules, connecting cables for the photovoltaic modules, and an arc detection device as provided in any of the above embodiments. The arc detection device is used to detect arcs on the connecting cables; or, the arc detection device is used to detect arcs on the connecting cables between the power converter and the power grid in the photovoltaic system.

[0151] The photovoltaic system and arc detection device provided in this application belong to the same inventive concept, can solve the same technical problem, and thus achieve the same technical effect. Repeated content will not be repeated here.

[0152] In one exemplary embodiment, this application also provides an arc detection method, applied to the processor in the arc detection device of any of the above embodiments, the method comprising:

[0153] S702, acquire parameter information of the cable under test and / or noise information of the environment in which the cable is located.

[0154] S704, adjust the filter passband of the filter circuit in the arc detection device according to the parameter information and / or noise information of the cable to be tested.

[0155] S706 determines the arc detection result based on the arc characteristic signal output by the filter circuit after the filter passband adjustment.

[0156] The arc detection method and arc detection device provided in the embodiments of this application belong to the same inventive concept, can solve the same technical problem, and thus achieve the same technical effect. Repeated content will not be repeated here.

[0157] In an exemplary embodiment, step S704 includes:

[0158] Based on the parameter and noise information of the cable to be tested, determine the target filter passband required for arc detection of the cable;

[0159] If the target filter passband does not match the current filter passband, a passband adjustment signal is generated based on the target filter passband.

[0160] Send a passband adjustment signal to the filter circuit to instruct the filter circuit to adjust the filter passband to the target filter passband.

[0161] In one exemplary embodiment, step S704 is followed by:

[0162] Adjust the gain of the filter circuit in the arc detection device based on the parameter and noise information of the cable to be tested.

[0163] The arc detection result is determined based on the arc characteristic signal output by the gain-adjusted filter circuit.

[0164] In one exemplary embodiment, this application also provides an arc detection device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the arc detection method described in any of the above embodiments.

[0165] In one exemplary embodiment, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the arc detection method described in any of the above embodiments.

[0166] In one exemplary embodiment, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the arc detection method described in any of the above embodiments.

[0167] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0168] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0169] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0170] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An arc detection device, characterized in that, The arc detection device includes: The sensing module is used to collect the arc characteristic signals of the cable; A filtering circuit, connected to the sensing module, is used to filter the arc characteristic signal collected by the sensing module. The processor, connected to the filtering circuit, is used to adjust the filter passband of the filtering circuit according to the parameter information of the cable and / or the noise information of the environment where the cable is located, and to determine the arc detection result based on the arc characteristic signal output by the filtering circuit after the filter passband adjustment.

2. The arc detection device according to claim 1, characterized in that, The filtering circuit includes a filter resistor module and a filter capacitor module; The processor is configured to adjust the filter passband of the filter circuit by adjusting the equivalent resistance value of the filter resistor module and / or the equivalent capacitance value of the filter capacitor module.

3. The arc detection device according to claim 2, characterized in that, The filter resistor module includes at least one filter resistor unit; The filter resistor unit includes a first filter resistor, a second filter resistor, and a first switch; The first filter resistor and the second filter resistor are connected in parallel, and the first switch is connected in series in the branch where the first filter resistor is located; or, the first filter resistor and the second filter resistor are connected in series, and the first switch is connected in parallel with the first filter resistor; the processor is connected to the first switch and is used to control the working state of the first switch to adjust the equivalent resistance value of the filter resistor module.

4. The arc detection device according to claim 2, characterized in that, The filter resistor module includes at least one variable filter resistor; The processor is connected to the resistance adjustment terminal of the variable filter resistor and is used to adjust the resistance value of the variable filter resistor through the resistance adjustment terminal, thereby adjusting the equivalent resistance value of the filter resistor module.

5. The arc detection device according to claim 2, characterized in that, The filter capacitor module includes at least one filter capacitor unit; The filter capacitor unit includes a first filter capacitor, a second filter capacitor, and a second switch; The first filter capacitor is connected in parallel with the second filter capacitor, and the second switch is connected in series in the branch where the first filter capacitor is located; or, the first filter capacitor is connected in series with the second filter capacitor, and the second switch is connected in parallel with the first filter capacitor; the processor is connected to the second switch and is used to control the working state of the second switch to adjust the equivalent capacitance value of the filter capacitor module.

6. The arc detection device according to any one of claims 2-5, characterized in that, The filtering circuit includes a high-pass filter and a low-pass filter; Both the high-pass filter and the low-pass filter include the filter resistor module and the filter capacitor module.

7. The arc detection device according to claim 6, characterized in that, The high-pass filter also includes a first operational amplifier; The filter resistor module in the high-pass filter is connected to the positive input terminal of the first operational amplifier, the output terminal of the first operational amplifier, and the filter capacitor module in the high-pass filter. The negative input terminal of the first operational amplifier is connected to reference ground.

8. The arc detection device according to claim 6, characterized in that, The low-pass filter also includes a second operational amplifier; The filter capacitor module in the low-pass filter is connected to the positive input terminal of the second operational amplifier, the output terminal of the second operational amplifier, and the filter resistor module in the low-pass filter. The negative input terminal of the second operational amplifier is connected to reference ground.

9. The arc detection device according to any one of claims 1-5, characterized in that, The filter circuit also includes a gain resistor module; The gain resistor module is connected to the processor; The processor is also configured to adjust the equivalent resistance value of the gain resistor module to adjust the gain of the filter circuit.

10. The arc detection device according to claim 9, characterized in that, The gain resistor module includes at least one gain resistor unit; The gain resistor unit includes a first gain resistor, a second gain resistor, and a third switch; The first gain resistor and the second gain resistor are connected in parallel, and the third switch is connected in series in the branch where the first gain resistor is located; or, the first gain resistor and the second gain resistor are connected in series, and the third switch is connected in parallel with the first gain resistor; the processor is connected to the third switch and is used to control the working state of the third switch to adjust the equivalent resistance value of the gain resistor module.

11. The arc detection device according to claim 9, characterized in that, The filtering circuit includes a high-pass filter and a low-pass filter, and both the high-pass filter and the low-pass filter include the gain resistor module.

12. A power converter, characterized in that, The power converter includes at least one arc detection device as described in any one of claims 1-11.

13. A photovoltaic system, characterized in that, The photovoltaic system includes connecting cables for photovoltaic modules and an arc detection device as described in any one of claims 1-11; The arc detection device is used to detect arcs on the connecting cable.

14. An arc detection method, characterized in that, The processor applied in the arc detection device as described in any one of claims 1-11, the method comprising: Collect parameter information of the cable under test and / or noise information of the environment in which the cable is located; Adjust the filter passband of the filter circuit in the arc detection device according to the parameter information of the cable to be tested and / or the noise information; The arc detection result is determined based on the arc characteristic signal output by the filter circuit after the filter passband adjustment.

15. The arc detection method according to claim 14, characterized in that, The step of adjusting the filter passband of the filter circuit in the arc detection device according to the parameter information of the cable to be tested and / or the noise information includes: Based on the parameter information of the cable to be tested and the noise information, determine the target filter passband required for arc detection of the cable; If the target filter passband does not match the current filter passband, a passband adjustment signal is generated based on the target filter passband. The passband adjustment signal is sent to the filter circuit to instruct the filter circuit to adjust the filter passband to the target filter passband.

16. The arc detection method according to claim 14, characterized in that, After adjusting the filter passband of the filter circuit in the arc detection device according to the parameter information of the cable to be tested and / or the noise information, the method further includes: Adjust the gain of the filter circuit in the arc detection device according to the parameter information of the cable to be tested and / or the noise information; The arc detection result is determined based on the arc characteristic signal output by the gain-adjusted filter circuit.

17. An arc detection device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the arc detection method as described in any one of claims 14-16.

18. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the arc detection method as described in any one of claims 14-16.

19. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the arc detection method as described in any one of claims 14-16.

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