Common-mode impedance adjusting circuit and arrangement method thereof

Abstract

The invention discloses a common-mode impedance adjusting circuit and an arrangement method thereof, and relates to the technical field of power grids. The voltage stabilizing circuit is connected with the access circuit; the access circuit comprises an energy taking coil wound on a wire and a front-end impact-resistant protection circuit connected with the energy taking coil; the voltage stabilizing circuit comprises a rectification filter circuit connected with the front-end anti-impact protection circuit, a DC / DC power supply connected with the rectification filter circuit, and a common mode inductor connected with the DC / DC power supply. Wherein the common mode inductor is connected to an interface of the DC / DC power supply and the infrared movement monitoring device; the common mode inductor adopts an annular magnetic core, and is formed by reversely winding two groups of windings with the same number of turns on the annular magnetic core. The winding, the resistor and the capacitor are connected to an original common mode inductor, the original circuit design is slightly changed, the size of the common mode inductor is basically not increased, and operation of a circuit system is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of power grids, and in particular to a common-mode impedance adjustment circuit method and system. Background Art

[0002] With the rapid development of modern society, electricity has become an indispensable part of people's daily life. In order to meet the increasing demand for electricity, the transmission voltage and power level of power grid lines are constantly increasing, and the transmission distance is also increasing. While the power system increases the transportation volume of electric energy resources, the stable operation of the power system is particularly important. Once a fault occurs, it will not only lead to insufficient power supply in local areas, but also cause power equipment to overheat and cause safety accidents, causing serious property losses to the society and inconvenience to people's lives. Therefore, in order to ensure the reliability and stability of power supply of the power grid, it is very necessary to conduct regular inspections of key nodes and power equipment of high-voltage transmission lines. The failure of various power equipment in the transmission line is closely related to its heating, so real-time monitoring of the heat and temperature of power equipment through sensors is one of the important means of power fault detection. Among them, infrared thermal imaging technology can monitor the operating status information of power equipment in real time, quickly and accurately without power outage, sampling or contact, and has become the most commonly used technical means for temperature detection.

[0003] However, when the monitoring device is powered, the switching devices in the power module often operate at a very high switching frequency. The high-speed opening and closing of the switching devices will cause large du / dt and di / dt, thereby generating serious electromagnetic interference (EMI). The conducted EMI flows through the infrared detector through the power line and interferes with the normal operation of the detector. Compared with the differential mode current, the common-mode leakage current caused by the common-mode stray loop can flow through the stray parameters of the power supply and the detector and the common ground loop. Therefore, the circulation of the common-mode leakage current makes it impossible to achieve electrical isolation between the power supply side and the detector load, which has a more serious impact on the system. Summary of the invention

[0004] In view of the problems existing in the existing common-mode impedance adjustment circuit and system, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is that EMI flows through the infrared detector via the power line, interfering with the normal operation of the detector.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a common-mode impedance adjustment circuit, which includes:

[0008] Access circuit;

[0009] A voltage stabilizing circuit connected to the access circuit;

[0010] The access circuit includes an energy-collecting coil wound on a wire, and a front-end anti-shock protection circuit connected to the energy-collecting coil;

[0011] The voltage stabilizing circuit includes a rectifier filter circuit connected to the front-end anti-shock protection circuit, a DC / DC power supply connected to the rectifier filter circuit, and a common mode inductor connected to the DC / DC power supply;

[0012] Wherein, the common mode inductor is connected to the interface between the DC / DC power supply and the infrared core monitoring device;

[0013] The common mode inductor adopts a toroidal magnetic core, and is formed by two groups of windings with the same number of turns being wound in opposite directions on the toroidal magnetic core.

[0014] As a preferred solution of the common-mode impedance adjustment circuit of the present invention, wherein: the energy-taking coil is used to induce electric potential on the wire and capture magnetic field energy;

[0015] The front-end anti-shock protection circuit is used to convert the alternating voltage / current into a direct current voltage / current and filter it, and then apply it to the DC / DC power supply;

[0016] The DC / DC power supply is used to provide voltage for the infrared core monitoring device.

[0017] In a second aspect, an embodiment of the present invention provides a method for arranging a common-mode impedance adjustment circuit, which comprises the following steps:

[0018] Collecting EMI values ​​in the power grid, and comparing the collected EMI values ​​with predetermined EMI values;

[0019] According to the comparison result, determining whether to set a common mode impedance adjustment circuit;

[0020] When setting up the common-mode impedance adjustment circuit, the load current in the power grid is collected and a secondary judgment is performed to complete the arrangement of the common-mode impedance adjustment circuit.

[0021] As a preferred solution of the arrangement method of the common mode impedance adjustment circuit of the present invention, the method of comparing the collected EMI value with the predetermined value of EMI includes:

[0022] The predetermined values ​​of EMI are set to K and L respectively, and the EMI values ​​are collected at the switch devices that are turned on and off at high speed, and the difference between the collected EMI values ​​and the predetermined values ​​K and L of EMI is determined;

[0023] When the collected EMI value is less than the predetermined EMI value K, the common mode impedance adjustment circuit is not set;

[0024] When the collected EMI value is ≥ the preset EMI value K, and < the preset EMI value L, an anti-interference cover is installed on the infrared core monitoring device;

[0025] When the collected EMI value is ≥ the predetermined value L of EMI, a common mode impedance adjustment circuit is arranged;

[0026] The predetermined value K of EMI is less than the predetermined value L of EMI, and the anti-interference cover is a component made of copper-plated EMI film material.

[0027] As a preferred solution of the arrangement method of the common mode impedance adjustment circuit of the present invention, the secondary judgment method includes:

[0028] Determine whether the load current on the wire is greater than the current threshold Q:

[0029] When the judgment result is not greater than the current threshold Q, solar energy and storage batteries are used to provide power to the common mode impedance adjustment circuit;

[0030] When the judgment result is greater than the current threshold Q, the energy collection coil is placed on the wire, and the potential on the wire is collected through the energy collection coil.

[0031] As a preferred solution of the arrangement method of the common-mode impedance adjustment circuit of the present invention, when arranging the common-mode inductor, winding AA' and winding BB' are wound on the annular magnetic core in opposite directions, and point A in winding AA' is connected to the positive pole of the DC / DC power supply, point A' in winding AA' is connected to the interface of the infrared core monitoring device, point B in winding BB' is connected to the negative pole of the DC / DC power supply, and point B' in winding BB' is connected to the interface of the infrared core monitoring device;

[0032] After the common-mode inductor is arranged, the inductor core is reused and a winding containing a damping resistor and a capacitor is connected on the basis of the common-mode inductor.

[0033] As a preferred arrangement method of the common-mode impedance adjustment circuit of the present invention, the winding AA' and the winding BB' are equivalent to a single winding L1, the winding connected with the damping resistor and the capacitor is L2, the mutual inductance generated by the two windings is M, and the impedance generated by the resistor and the capacitor is Z. Therefore, the relationship between the current and the voltage is expressed as:

[0034]

[0035] Then perform Laplace transform and equate the secondary side impedance to the primary side, and the formula is:

[0036]

[0037] In the formula, Z2 (s) represents the equivalent impedance of the secondary side converted to the primary side, Z total Expressed as total impedance;

[0038] Equivalent impedance Z 2 (s) is designed to increase the total impedance Z of the common mode inductor total When the damping resistor and capacitor are connected to the secondary circuit, the equivalent impedance Z 2 (s) is expressed as:

[0039]

[0040] Then the equivalent impedance Z 2 Substitute the expression of (s) into the total impedance expression Z total In the formula, we get:

[0041]

[0042] Among them, Z total (s) represents the newly calculated total impedance with the added common-mode inductance.

[0043] In a third aspect, an embodiment of the present invention provides a common-mode impedance adjustment circuit system, which includes an information acquisition module, a judgment module, and an adjustment module;

[0044] The information acquisition module is used to monitor the EMI level in the power grid, provide data for subsequent comparison and judgment, and collect the load current in the power grid;

[0045] The judgment module is used to compare the collected EMI value with the preset EMI values ​​K and L to determine whether a common-mode impedance adjustment circuit needs to be arranged, and to determine whether the load current on the wire exceeds the preset current threshold Q to determine the power supply mode;

[0046] The adjustment module is used to change the secondary resistance and capacitance parameters to enhance the total impedance.

[0047] In a fourth aspect, an embodiment of the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein: when the processor executes the computer program, any step of the above-mentioned common-mode impedance adjustment circuit method is implemented.

[0048] In a fifth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, any step of the above-mentioned common-mode impedance adjustment circuit method is implemented.

[0049] The beneficial effects of the present invention are as follows: by additionally connecting a winding containing a damping resistor and a capacitor to the common-mode inductor, the purpose of improving the common-mode impedance is achieved. Compared with only adding a resistor, this method can not only effectively increase the high-frequency common-mode impedance, but also change the secondary side impedance resonant frequency converted to the primary side by adjusting the resistor and capacitor parameters, thereby effectively suppressing the common-mode EMI in a specific frequency band;

[0050] Secondly, connecting windings, resistors and capacitors to the original common-mode inductor will only cause minor changes to the original circuit design, and will basically not increase the volume of the common-mode inductor, making the operation of the circuit system more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0052] Figure 1 This is the structural diagram of the common-mode impedance adjustment circuit.

[0053] Figure 2 This is a schematic diagram of common-mode inductor winding after adding damping resistors and inductor windings.

[0054] Figure 3 This is the equivalent circuit structure diagram of the common-mode inductor after adding the damping resistor and inductor winding.

[0055] Figure 4 Schematic diagram of the equivalent common-mode loop of the common-mode impedance adjustment circuit.

[0056] Figure 5 The figure is a flow chart of a method for arranging a common-mode impedance adjustment circuit. DETAILED DESCRIPTION

[0057] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0058] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0059] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0060] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0061] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0062] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] Example 1

[0064] Reference Figure 1 to Figure 4 , is the first embodiment of the present invention, which provides a common-mode impedance adjustment circuit method, including:

[0065] Access circuit 100;

[0066] A voltage stabilizing circuit 200 connected to the access circuit 100;

[0067] The access circuit 100 includes an energy-collecting coil 101 wound on a wire, and a front-end anti-shock protection circuit 102 connected to the energy-collecting coil 101;

[0068] When the power grid is operating normally, there is a high load current on the transmission line, so there is a power frequency magnetic field around the transmission line. The energy collection coil 101 can be used to induce an electric potential on the wire and capture the magnetic field energy.

[0069] The voltage stabilizing circuit 200 includes a rectifier filter circuit 201 connected to the front-end anti-shock protection circuit 102, a DC / DC power supply 202 connected to the rectifier filter circuit 201, and a common mode inductor 203 connected to the DC / DC power supply 202;

[0070] To ensure the safety of the subsequent circuits, limit the amplitude of the input voltage, and resist lightning current, the alternating voltage induced by the coil first passes through the front-end anti-shock protection circuit 102, and then passes through the rectifier and filter circuit to rectify the alternating voltage / current into a DC value and then filter it, so as to provide high-quality DC voltage for the subsequent circuits. The front-end anti-shock protection circuit 102 is used to convert the alternating voltage / current into a DC voltage / current and filter it, and then act on the DC / DC power supply 202;

[0071] Among them, the common mode inductor 203 is connected to the interface between the DC / DC power supply 202 and the infrared core monitoring device;

[0072] The common mode inductor 203 adopts a toroidal magnetic core, and is formed by two sets of windings with the same number of turns being wound in opposite directions on the toroidal magnetic core;

[0073] The DC / DC power supply 202 is used to provide voltage for the infrared core monitoring device.

[0074] When in use, in order to suppress the common-mode EMI caused by the switching device, it is necessary to connect a common-mode inductor in series between the DC / DC power supply 202 and the infrared movement monitoring device to increase the impedance of the common-mode loop. The connection method of the common-mode inductor is as follows: Figure 1 shown.

[0075] In summary, the common-mode inductor 203 adopts a toroidal magnetic core and is formed by two sets of windings AA` and BB` with the same number of turns wound in opposite directions. The common-mode current flows into the A end and the B end respectively, and the same-direction magnetic field is generated in the coil to increase the inductive reactance of the coil, thereby producing a strong damping effect, thereby attenuating the common-mode current and achieving the purpose of reducing common-mode EMI.

[0076] Example 2

[0077] Reference Figure 1 to Figure 5 Based on the first embodiment, this embodiment further provides a method for arranging a common-mode impedance adjustment circuit, comprising the following steps:

[0078] S1. Collect the EMI value in the power grid, and compare the collected EMI value with the preset EMI value.

[0079] Methods for comparing the collected EMI value with the predetermined EMI value include:

[0080] The predetermined values ​​of EMI are set to K and L respectively, and the EMI values ​​are collected at the switch devices that are turned on and off at high speed, and the difference between the collected EMI values ​​and the predetermined values ​​K and L of EMI is determined;

[0081] When the collected EMI value is less than the predetermined EMI value K, the common mode impedance adjustment circuit is not set;

[0082] When the collected EMI value is ≥ the preset EMI value K, and < the preset EMI value L, an anti-interference cover is installed on the infrared core monitoring device;

[0083] When the collected EMI value is ≥ the predetermined value L of EMI, a common mode impedance adjustment circuit is arranged;

[0084] In implementation, the predetermined value K of EMI is set to 30dBμV / m. When the detected EMI value is small, it is not necessary to set the common mode impedance adjustment circuit. The predetermined value L of EMI is set to 50dBμV / m to ensure that when the EMI level reaches this level, measures must be taken to avoid violating the standard.

[0085] The predetermined value K of EMI is less than the predetermined value L of EMI, and the anti-interference cover is a component made of copper-plated EMI film material.

[0086] S2. Determine whether to set a common-mode impedance adjustment circuit based on the comparison result.

[0087] Providing a common-mode impedance adjustment circuit can effectively protect the monitoring device.

[0088] S3. When setting the common-mode impedance adjustment circuit, the load current in the power grid is collected and a secondary judgment is performed to complete the arrangement of the common-mode impedance adjustment circuit.

[0089] Secondary judgment methods include:

[0090] Determine whether the load current on the wire is greater than the current threshold Q:

[0091] When the judgment result is not greater than the current threshold Q, solar energy and storage batteries are used to provide power to the common mode impedance adjustment circuit;

[0092] When the judgment result is greater than the current threshold value Q, the energy collection coil 101 is placed on the wire, and the potential on the wire is collected through the energy collection coil 101;

[0093] A current threshold Q is set to ensure that the energy harvesting coil 101 can effectively collect enough current on the wire to power the DC / DC power supply 202. When the current is less than the set current threshold Q, other methods can be used to power the DC / DC power supply 202.

[0094] When arranging the common mode inductor 203, winding AA' and winding BB' are reversely wound on the annular magnetic core, and point A in winding AA' is connected to the positive pole of the DC / DC power supply 202, point A' in winding AA' is connected to the interface of the infrared core monitoring device, point B in winding BB' is connected to the negative pole of the DC / DC power supply 202, and point B' in winding BB' is connected to the interface of the infrared core monitoring device;

[0095] After the common mode inductor 203 is arranged, the inductor core is reused, and a winding containing a damping resistor and a capacitor is connected to the common mode inductor 203, that is, Figure 2 shown.

[0096] like Figure 3 and Figure 4 As shown, winding AA' and winding BB' are equivalent to a single winding L1, and the winding containing damping resistance and capacitance is connected to L2. The mutual inductance generated by the two windings is M, and the impedance generated by the resistance and capacitance is Z. Therefore, the relationship between current and voltage is expressed as:

[0097]

[0098] Then perform Laplace transform and equate the secondary side impedance to the primary side, and the formula is:

[0099]

[0100] In the formula, Z 2 (s) represents the equivalent impedance of the secondary side converted to the primary side, Z total Expressed as total impedance;

[0101] Equivalent impedance Z 2 (s) is designed to increase the total impedance Z of the common mode inductor total When the damping resistor and capacitor are connected to the secondary circuit, the equivalent impedance Z 2 (s) is expressed as:

[0102]

[0103] Then the equivalent impedance Z 2 Substitute the expression of (s) into the total impedance expression Z total In the formula, we get:

[0104]

[0105] Among them, Z total (s) represents the newly calculated total impedance with the added common-mode inductance.

[0106] In summary, by adding an additional winding containing a damping resistor and a capacitor to the common-mode inductor to achieve the purpose of improving the common-mode impedance, compared with only adding resistance, this method can not only effectively increase the high-frequency common-mode impedance, but also change the secondary side impedance resonant frequency converted to the primary side by adjusting the resistance and capacitance parameters, thereby effectively suppressing the common-mode EMI in a specific frequency band; secondly, connecting the winding, resistor and capacitor to the original common-mode inductor will only cause minor changes to the original circuit design, and will basically not increase the volume of the common-mode inductor, which is convenient for the operation of the circuit system.

[0107] Example 3

[0108] On the basis of the previous two embodiments, this embodiment further provides a common mode impedance adjustment circuit system, including an information acquisition module, a judgment module, and an adjustment module;

[0109] The information acquisition module is used to monitor the EMI level in the power grid, provide data for subsequent comparison and judgment, and collect the load current in the power grid;

[0110] The judgment module is used to compare the collected EMI value with the preset EMI values ​​K and L to determine whether a common-mode impedance adjustment circuit needs to be arranged, and to determine whether the load current on the wire exceeds the preset current threshold Q to determine the power supply mode;

[0111] The adjustment module is used to change the secondary resistance and capacitance parameters to enhance the total impedance.

[0112] This embodiment also provides a computer device, which is applicable to the case of a common-mode impedance adjustment circuit method, and includes a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the common-mode impedance adjustment circuit method proposed in the above embodiment.

[0113] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0114] This embodiment further provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for implementing a common-mode impedance adjustment circuit as proposed in the above embodiment is implemented.

[0115] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0116] Example 4

[0117] On the basis of the previous three embodiments, this embodiment provides a common-mode impedance adjustment circuit method. In order to verify the beneficial effects of the present invention, a scientific demonstration is carried out through simulation experiments.

[0118] A common-mode inductor model without an additional winding is established as a basis for comparison. An additional winding is designed on the common-mode inductor, including a damping resistor and capacitor. Appropriate resistor and capacitor values ​​are selected to achieve the desired impedance characteristics.

[0119] The baseline model and the additional winding model are simulated to analyze the change of common mode impedance with frequency and observe the effect of additional winding on common mode impedance at a specific frequency. The parameters are as follows:

[0120]

[0121] It can be seen from the table that the present invention can effectively solve the problem of EMI and can suppress EMI in a specific frequency band, thereby ensuring the stable operation of the infrared movement monitoring device.

[0122] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A common mode impedance adjustment circuit, characterized in that: include, Access circuit (100); A voltage stabilizing circuit (200) connected to the access circuit (100); The access circuit (100) comprises an energy collection coil (101) wound on a wire, and a front-end anti-impact protection circuit (102) connected to the energy collection coil (101); The voltage stabilizing circuit (200) comprises a rectifier filter circuit (201) connected to the front-end anti-impact protection circuit (102), a DC / DC power supply (202) connected to the rectifier filter circuit (201), and a common mode inductor (203) connected to the DC / DC power supply (202); Wherein, the common mode inductor (203) is connected to the interface between the DC / DC power supply (202) and the infrared core monitoring device; The common mode inductor (203) adopts a toroidal magnetic core and is formed by two groups of windings with the same number of turns being wound in opposite directions on the toroidal magnetic core.

2. The common mode impedance adjustment circuit method according to claim 1, wherein: The energy collection coil (101) is used to induce electric potential on the wire and capture magnetic field energy; The front-end anti-shock protection circuit (102) is used to convert the alternating voltage / current into a direct current voltage / current and filter it, and then apply it to the DC / DC power supply (202); The DC / DC power supply (202) is used to provide voltage for the infrared core monitoring device.

3. A method for arranging a common-mode impedance adjustment circuit, characterized in that: The following steps are included: Collecting EMI values ​​in the power grid, and comparing the collected EMI values ​​with predetermined EMI values; According to the comparison result, determining whether to set a common mode impedance adjustment circuit; When setting up the common-mode impedance adjustment circuit, the load current in the power grid is collected and a secondary judgment is performed to complete the arrangement of the common-mode impedance adjustment circuit.

4. The method for arranging a common-mode impedance adjustment circuit according to claim 3, wherein: Methods for comparing the collected EMI value with the predetermined EMI value include: The predetermined values ​​of EMI are set to K and L respectively, and the EMI values ​​are collected at the switch devices that are turned on and off at high speed, and the difference between the collected EMI values ​​and the predetermined values ​​K and L of EMI is determined; When the collected EMI value is less than the predetermined EMI value K, the common mode impedance adjustment circuit is not set; When the collected EMI value is ≥ the preset EMI value K, and < the preset EMI value L, an anti-interference cover is installed on the infrared core monitoring device; When the collected EMI value is ≥ the predetermined value L of EMI, a common mode impedance adjustment circuit is arranged; The predetermined value K of EMI is less than the predetermined value L of EMI, and the anti-interference cover is a component made of copper-plated EMI film material.

5. The method for arranging a common-mode impedance adjustment circuit according to claim 4, characterized in that: The secondary judgment method includes: Determine whether the load current on the wire is greater than the current threshold Q: When the judgment result is not greater than the current threshold Q, solar energy and storage batteries are used to provide power to the common mode impedance adjustment circuit; When the judgment result is greater than the current threshold value Q, the energy collection coil (101) is sleeved on the conductor, and the electric potential on the conductor is collected through the energy collection coil (101).

6. The method for arranging a common-mode impedance adjustment circuit according to claim 5, characterized in that: When arranging the common mode inductor (203), the winding AA' and the winding BB' are wound on the annular magnetic core in opposite directions, and the point A in the winding AA' is connected to the positive pole of the DC / DC power supply (202), the point A' in the winding AA' is connected to the interface of the infrared core monitoring device, the point B in the winding BB' is connected to the negative pole of the DC / DC power supply (202), and the point B' in the winding BB' is connected to the interface of the infrared core monitoring device; After the common mode inductor (203) is arranged, a winding including a damping resistor and a capacitor is connected to the common mode inductor (203) by reusing the inductor magnetic core.

7. The method for arranging a common-mode impedance adjustment circuit according to claim 6, wherein: The winding AA' and the winding BB' are equivalent to a single winding L1, and the winding containing the damping resistor and the capacitor is connected to L2. The mutual inductance generated by the two windings is M, and the impedance generated by the resistor and the capacitor is Z. Therefore, the relationship between the current and voltage is expressed as: Then perform Laplace transform and equate the secondary side impedance to the primary side, and the formula is: Where Z2(s) is the equivalent impedance from the secondary side to the primary side, Z total Expressed as total impedance; The equivalent impedance Z2(s) is designed to increase the total impedance Z of the common mode inductor total , when the damping resistor and capacitor are connected to the secondary circuit, the equivalent impedance Z2(s) is expressed as: Then substitute the expression of equivalent impedance Z2(s) into the total impedance expression Z total In the formula, we get: Among them, Z total (s) represents the newly calculated total impedance with the added common-mode inductance.

8. A common-mode impedance adjustment circuit system, based on the common-mode impedance adjustment circuit method according to any one of claims 3 to 7, characterized in that: It includes an information collection module, a judgment module, and an adjustment module; The information acquisition module is used to monitor the EMI level in the power grid, provide data for subsequent comparison and judgment, and collect the load current in the power grid; The judgment module is used to compare the collected EMI value with the preset EMI values ​​K and L to determine whether a common-mode impedance adjustment circuit needs to be arranged, and to determine whether the load current on the wire exceeds the preset current threshold Q to determine the power supply mode; The adjustment module is used to change the secondary resistance and capacitance parameters to enhance the total impedance.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the common-mode impedance adjustment circuit method according to any one of claims 3 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the common-mode impedance adjustment circuit method according to any one of claims 3 to 7 are implemented.

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