Method for reducing electromagnetic interference of transmission line, magnetic ring winding group and air conditioner

Abstract

The present application provides a method for reducing electromagnetic interference of a transmission line, a magnetic ring winding group, and an air conditioner. The magnetic ring winding group includes a first magnetic ring and a second magnetic ring. The transmission line includes an incoming line segment, a winding segment, and an outgoing line segment connected in sequence. The direction from the incoming line segment to the outgoing line segment is the first extension direction. The incoming line segment is located outside the first magnetic ring and the second magnetic ring. The first end of the winding segment is connected to one end of the incoming line segment. The winding segment is composed of N turns of magnetic ring winding wires. Among them, after the winding segment passes through the first magnetic ring from the first surface of the first magnetic ring along the first extension direction, it then passes through the first magnetic ring from the first surface of the second magnetic ring to form one turn of magnetic ring winding wire, where N≥1. The outgoing line segment is located outside the second magnetic ring, and the first end of the outgoing line segment is connected to the second end of the winding segment. The outgoing line segment passes through the first magnetic ring from the first surface of the first magnetic ring along the first extension direction. The adjustment ability of the magnetic ring to resist electromagnetic interference is improved.

Description

Technical Field

[0001] The present application relates to the electromagnetic field, and particularly to a method for reducing electromagnetic interference of transmission lines, a magnetic ring winding group, and an air conditioner. Background Art

[0002] Transmission lines such as power lines are the main channels for electromagnetic interference to enter and exit devices. Taking the power line as an example, through the power line, electromagnetic interference from the grid side can enter the device and interfere with the normal operation of the device. The electromagnetic interference generated by the device may also be transmitted to the grid through the power line, interfering with the normal operation of other networked devices.

[0003] People usually use filters to reduce electromagnetic interference. When the filter cannot meet the filtering requirements, a magnetic ring is added to the output line of the filter to improve its filtering performance and reduce the entry and exit of electromagnetic interference.

[0004] In the prior art, as Figure 1 shown, two first magnetic rings 1 and second magnetic rings 2 of the same type are often used, and the transmission line 3 ( Figure 1 in which the transmission line 3 in

[0005] is the neutral wire and the live wire) is wound around these two magnetic rings; the winding methods of the two magnetic rings usually adopt the same-direction and forward-winding method, that is, the two magnetic rings are stacked together and directly wound with wire. Among them, the transmission line requires a longer wire, and as the number of winding turns increases, the inter-turn capacitance will cause the best suppression frequency point of the magnetic ring winding group to move forward significantly, especially in the low-frequency band. For each additional turn of winding, the change amplitude of the best suppression frequency point is relatively large, resulting in difficulty in adjusting the number of winding turns to reduce the frequency difference between the best suppression frequency of the magnetic ring winding group and the frequency of the electromagnetic interference resonance peak. Therefore, the adjustable performance of the magnetic ring winding group is relatively poor, especially in the low-frequency band (such as the frequency band less than 30 MHz). Summary of the Invention

[0006] The present application provides a method for reducing electromagnetic interference of transmission lines, a magnetic ring winding group, and an air conditioner to solve the above problems.

[0007] To solve the above problems, as an aspect of the present application, a magnetic ring winding group is provided, including:

[0008] A first magnetic ring and a second magnetic ring;

[0009] A transmission line, including an incoming line segment, a winding segment, and an outgoing line segment connected in sequence, and the direction from the incoming line segment to the outgoing line segment is the first extension direction;

[0010] The incoming line segment is located outside the first magnetic ring and the second magnetic ring;

[0011] The first end of the winding section is connected to one end of the incoming line section. The winding section is composed of N turns of magnetic ring wire windings. Among them, after the winding section passes through the first face of the first magnetic ring along the first extension direction and then passes through the first face of the second magnetic ring to form one turn of magnetic ring wire winding, N≥1;

[0012] The outgoing line section is located outside the second magnetic ring. The first end of the outgoing line section is connected to the second end of the winding section. The outgoing line section passes through the first face of the first magnetic ring along the first extension direction.

[0013] Optionally, the transmission line includes a live wire and a neutral wire;

[0014] Or,

[0015] The transmission line includes a live wire, a neutral wire, and an auxiliary wire. The auxiliary wire includes a ground wire and / or a communication wire.

[0016] Optionally, it further includes: a common mode choke;

[0017] The common mode choke is connected to the live wire of the outgoing line section.

[0018] Optionally, the first magnetic ring and the second magnetic ring are of the same type;

[0019] And / or, the first magnetic ring and the second magnetic ring have the same optimal suppression frequency point.

[0020] Optionally, the first magnetic ring is a nickel-zinc magnetic ring, a manganese-zinc ferrite magnetic ring, or a magnesium-zinc ferrite magnetic ring;

[0021] And / or, the second magnetic ring is a nickel-zinc magnetic ring, a manganese-zinc ferrite magnetic ring, or a magnesium-zinc ferrite magnetic ring.

[0022] Optionally, the first magnetic ring is an enclosed magnetic ring or a snap-on magnetic ring;

[0023] And / or, the second magnetic ring is an enclosed magnetic ring or a snap-on magnetic ring.

[0024] Optionally, the first magnetic ring and the second magnetic ring are arranged side by side.

[0025] This application also proposes a method for reducing electromagnetic interference of a transmission line, including:

[0026] Winding the first magnetic ring group and the second magnetic ring group with a transmission line to form a magnetic ring group according to any one proposed in this application.

[0027] Optionally, it further includes:

[0028] Adjusting the number of turns N of the magnetic ring wire windings in the magnetic ring group to change the optimal suppression frequency point of the magnetic ring group.

[0029] This application also proposes an air conditioner, including a magnetic ring group according to any one proposed in this application.

[0030] The present application provides a method for reducing electromagnetic interference of transmission lines, a magnetic ring winding group, and an air conditioner. The number of turns of the transmission line passing through the second magnetic ring is 1 less than the number of turns passing through the first magnetic ring. When the number of turns of the magnetic ring winding is changed, the change amount of the optimal suppression frequency point is small, thereby improving the adjustment ability of the magnetic ring to resist electromagnetic interference, and the required winding length of the magnetic ring winding group proposed in the present application is short. Description of the Drawings

[0031] Figure 1 It is a schematic diagram of a magnetic ring winding group in the prior art;

[0032] Figure 2 It is a schematic diagram of a magnetic ring winding group in an embodiment of the present application;

[0033] Figure 3 It is a schematic diagram of another magnetic ring winding group in an embodiment of the present application;

[0034] Figure 4 It is a schematic diagram comparing the impedance test results of the magnetic ring windings of the present application and the prior art;

[0035] Figure 5 It is the electromagnetic emission test result of the magnetic ring winding group using the prior art in the comparative example;

[0036] Figure 6 It is the electromagnetic emission test result of the magnetic ring winding group of the present application in the comparative example.

[0037] Reference Signs in the Drawings: 1. First magnetic ring; 1. First magnetic ring; 11. First surface of the first magnetic ring; 2. Second magnetic ring; 21. Second surface of the second magnetic ring; 3. Transmission line; 31. Incoming line segment; 32. Winding segment; 33. Outgoing line segment; 3. Transmission line; 4. Common-mode inductor; 5. Filter circuit. Detailed Embodiments

[0038] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in conjunction with specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts shall fall within the protection scope of the present application.

[0039] It should be noted that in the description and claims of this application and the above-mentioned drawings, terms such as "first" and "second" are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that such data used can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or device comprising a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0040] In the prior art, magnetic rings are usually wound around a transmission line to reduce electromagnetic interference. In the prior art, when two magnetic rings are wound, the magnetic rings are usually stacked together, and the same-directional winding method as shown in Figure 1 is adopted to form a magnetic ring winding group by winding on the stacked magnetic rings. In order to adjust the optimal suppression frequency point of the magnetic ring winding group, usually the number of turns of the transmission line on the magnetic ring winding group is changed. When the number of turns of the transmission line wound on the magnetic ring winding group increases, the corresponding optimal suppression frequency point of the magnetic ring winding group will also change. When using the stacked method in the prior art, for each increase or decrease of one turn of the winding wire, the change amount of the optimal suppression frequency point is relatively large. Due to the large change amount, the adjustability of the magnetic ring winding group is poor, especially the adjustability in the low-frequency band is poor. For example, assume that when winding 4 turns in the way of Figure 1 , the optimal suppression frequency point of the magnetic ring winding group is 20 MHz, and the optimal suppression frequency point after increasing one turn is 10 MHz. Then when the desired optimal suppression frequency point is 13 MHz, when using the same-directional winding method as shown in Figure 1 , the frequency between the obtained frequency point and the desired frequency point is relatively large, and the suppression effect is poor. If when increasing the winding wire of the magnetic ring winding group, the decrease amount of the optimal suppression frequency point is reduced, for example, making the optimal suppression frequency point move to 12 MHz, the suppression effect can be improved.

[0041] After analysis, the inventors of the present application believe that if the change amount of the optimal suppression frequency point when increasing one turn of the winding wire can be reduced, then the adjustability of the magnetic ring winding group can be increased, especially the adjustability in the low-frequency range (for example, the range less than 30 MHz).

[0042] Based on the above idea, the present application proposes a magnetic ring winding group, as shown in Figure 2 , including: a first magnetic ring 1, a second magnetic ring 2 and a transmission line 3; the first magnetic ring 1 and the second magnetic ring 2 can be magnetic rings of the same type, can be prepared from the same material, and their sizes can be the same. The transmission line 3 can be, for example, a communication line or the live wire and neutral wire of an electrical device. Figure 2Taking the transmission line as the neutral line and the live line as an example for demonstration. The transmission line 3 includes an incoming line segment 31, a winding segment 32, and an outgoing line segment 33 connected in sequence. The direction extending from the incoming line segment 31 to the outgoing line segment 33 is the first extension direction;

[0043] The incoming line segment 31 is located outside the first magnetic ring 1 and the second magnetic ring 2; the first end of the winding segment 32 is connected to one end of the incoming line segment 31. The winding segment is composed of N turns of magnetic ring winding wires. Among them, after the winding segment 32 passes through the first magnetic ring 1 from the first surface 11 of the first magnetic ring along the first extension direction, and then passes through the second magnetic ring 2 from the first surface 21 of the second magnetic ring to form one turn of the magnetic ring winding wire, N≥1, and optionally N is not less than 2; the outgoing line segment 33 is located outside the second magnetic ring 2, the first end of the outgoing line segment 33 is connected to the second end of the winding segment 32, and the outgoing line segment 33 passes through the first magnetic ring 1 from the first surface 11 of the first magnetic ring along the first extension direction.

[0044] Please refer to Figure 2 and Figure 1 , in the prior art, the transmission line 3 passes through the first magnetic ring and the second magnetic ring, so the number of turns wound in the first magnetic ring and the second magnetic ring is the same. In the magnetic ring winding group proposed in this application, the outgoing line segment only passes through the first magnetic ring and does not pass through the second magnetic ring. Therefore, when the transmission line is wound with the same number of turns, for example Figure 1 and Figure 2 both only wind one turn. The number of transmission lines passing through the second magnetic ring 2 in this application is 1 less than the number of transmission lines passing through the second magnetic ring in the prior art. And the inductive reactance of the magnetic ring is linearly related to the square of the number of turns wound on the magnetic ring, that is, the larger the square of the number of turns wound, the greater the inductive reactance, and the lower the frequency of the optimal suppression frequency point of the magnetic ring winding group. When adding one turn, the change amount of the optimal suppression frequency point is related to the number of turns of the magnetic ring, and the more the number of turns, the greater the change amount. Because the number of transmission lines passing through the second magnetic ring in this application is 1 less than the number of lines passing through the second magnetic ring in the prior art, it is equivalent that the number of turns on the second magnetic ring in this application is less than the number of turns on the second magnetic ring in the prior art. Therefore, when adding one turn, the change amount of the optimal suppression frequency point of the magnetic ring winding line proposed in this application is smaller. And because the outgoing line segment does not need to pass through the second magnetic ring 2, so in the case of the same number of turns, the winding length required for the magnetic ring winding group proposed in this application is less.

[0045] In some alternative embodiments, the transmission line 3 includes a live line and a neutral line; specifically, as Figure 2 shown, Figure 2 the transmission line in

[0046] In some alternative embodiments, the transmission line 3 includes a live wire, a neutral wire, and an auxiliary wire, and the auxiliary wire includes a ground wire and / or a communication wire. Specifically, in this embodiment, the transmission line can be the power cord of an electrical device, and the power cord can include a ground wire, or the transmission line can include a communication wire, because the communication wire is also a common electromagnetic interference transmission path. The various wires in the transmission line are arranged side by side.

[0047] In some alternative embodiments, what is proposed in this application further includes: a differential-mode inductor 4; please refer to Figure 3 , and the differential-mode inductor 4 is connected to the live wire of the outgoing line segment. The other end of the differential-mode inductor that is not connected to the outgoing line segment can be connected to a filter circuit, and at the same time, the neutral wire can also be connected to the filter circuit. The core type of the differential-mode inductor can be selected as a nickel-zinc core, a magnesium-zinc core, an open amorphous core, or a powder core. By adding a differential-mode inductor, differential-mode interference can be filtered out, further improving the anti-interference ability.

[0048] In some alternative embodiments, the first magnetic ring and the second magnetic ring are of the same type; and / or, the first magnetic ring and the second magnetic ring have the same optimal suppression frequency point. Here, the same type of magnetic ring means that the material and shape structure of the magnetic ring are the same. When the optimal suppression frequency points of the first magnetic ring and the second magnetic ring are the same, the matching of the first magnetic ring and the second magnetic ring is more convenient, and there is no need for repeated combination experiments.

[0049] In some alternative embodiments, the first magnetic ring is a nickel-zinc magnetic ring, a manganese-zinc ferrite magnetic ring, or a magnesium-zinc ferrite magnetic ring; and / or, the second magnetic ring is a nickel-zinc magnetic ring, a manganese-zinc ferrite magnetic ring, or a magnesium-zinc ferrite magnetic ring. Specifically, the first magnetic ring and the second magnetic ring can adopt different types of magnetic rings. For example, the first magnetic ring is a manganese-zinc ferrite magnetic ring, and the second magnetic ring is a nickel-zinc ferrite magnetic ring.

[0050] In some alternative embodiments, the first magnetic ring is a closed magnetic ring or a snap-type magnetic ring; and / or, the second magnetic ring is a closed magnetic ring or a snap-type magnetic ring. For any snap-type magnetic ring, it can be composed of two semi-circular magnetic rings.

[0051] In some alternative embodiments, the first magnetic ring 1 and the second magnetic ring 2 are arranged side by side. Specifically, in this case, it is preferred that the first magnetic ring and the second magnetic ring have the same size and shape. When the first magnetic ring and the second magnetic ring are arranged side by side, the amount of transmission line required for winding is the least, thereby reducing the usage amount of the transmission line.

[0052] To better illustrate the advantages of this application, a comparative example of this application and the prior art is presented below.

[0053] In an outdoor unit of a variable-frequency air conditioner project, an interference peak appears near the electromagnetic interference spectrum of 13 MHz. To suppress the interference near 13 MHz, two magnetic rings can be wound around the power cord so that the impedance resonance peak of the magnetic rings is near 13 MHz. Two power cords (neutral and live) are wound around the magnetic rings with a certain number of turns, and the impedance characteristics of both ends of the power cord are measured using an impedance analyzer. If the measured impedance resonance peak is near 13 MHz, the requirement is met. Now, using the winding method as shown in Figure 1 , the first magnetic ring 1 and the second magnetic ring 2 are wound together for four turns, and the measured optimal suppression point frequency is Figure 4 The m1 point in, corresponding to 29 MHz (solid line); when one more turn is added and the first magnetic ring 1 and the second magnetic ring 2 are wound together for five turns, the measured resonance point of the optimal suppression point of the magnetic ring winding is Figure 4 The m3 in, corresponding to 7.5 MHz (long dashed line). The electromagnetic emission test is carried out on the magnetic ring winding when it is wound for five turns using the existing method, and the test results are as shown in Figure 5 . It can be seen that the lowest margin near 13 MHz is 7.78 dB.

[0054] When using the winding method in this application Figure 2 , when the first magnetic ring 1 is wound for five turns and the second magnetic ring 2 is wound for four turns, the measured optimal suppression point frequency of the magnetic ring winding is Figure 4 The m2 point in, corresponding to 13 MHz (dot line). As can be seen from Figure 4 , when two magnetic rings are wound in the way of the existing technology, it is easy for its resonance peak (optimal suppression point frequency) to miss the desired point. However, using this application can make up for the deficiencies of the winding method in the existing technology. The movement of the optimal suppression frequency point is small. When using the winding method of the existing technology, the optimal suppression frequency point moves too much, directly moving from 29 MHz to 7.5 MHz and missing the desired 13 MHz. Therefore, when using the winding method proposed in this application at this time, because the second magnetic ring passes through one less turn, the decrease in the optimal suppression frequency point is small and only moves to 13 MHz, thus obtaining the desired optimal frequency point. At the same time, when the number of turns of the first magnetic ring is the same, the transmission line used in this application is shorter than that of the existing technology. The reason for the deficiency of the winding method of the existing technology is that each turn wound is equivalent to increasing the inductance of the two magnetic rings, and the stray inductance brought by the line length and the inter-turn capacitance will also increase as the number of turns wound increases. The magnetic ring is equivalent to an RLC parallel circuit of an inductor. When the equivalent inductance and equivalent capacitance become larger, the frequency value corresponding to the optimal suppression frequency point will decrease. When using the magnetic ring winding proposed in this application, since the transmission line in the second magnetic ring is always less than that in the first magnetic ring, the optimal suppression frequency point is relatively larger when the number of turns is the same as that of the existing technology. For the method proposed in this application, the power cord (neutral and live) is wound 5 turns around the first magnetic ring 1 and 4 turns around the second magnetic ring 2, and the final sweep measures its electromagnetic emission spectrum as shown in Appendix Figure 6As shown, the lowest margin is 12.25 dB near 13M, which is significantly higher than the 7.78 dB in the attached Figure 5 . It can be seen that the method proposed in this application can reduce the offset of the optimal suppression frequency point. When the magnetic ring winding of the existing technology increases by one turn of winding, the frequency of the optimal suppression frequency point decreases too much and the desired optimal suppression frequency point cannot be obtained. By using the magnetic ring winding proposed in this application, the offset of the optimal suppression frequency point can be reduced, so as to obtain a magnetic ring winding in which the optimal suppression frequency point is closer to the desired frequency point.

[0055] This application also proposes a method for reducing electromagnetic interference of transmission lines, including:

[0056] Winding the first magnetic ring winding and the second magnetic ring winding with the transmission line to form the magnetic ring winding described in any one of the proposals of this application.

[0057] Optionally, it further includes: adjusting the number of turns N of the magnetic ring wire in the magnetic ring winding to change the optimal frequency point of the magnetic ring winding. Specifically, the number of turns is changed according to the desired optimal suppression frequency point.

[0058] This application also proposes an air conditioner, including the magnetic ring winding described in any one of the proposals of this application.

[0059] The above are only the preferred embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A magnetic winding group, characterized in that, Comprising: A first magnetic ring (1) and a second magnetic ring (2); A transmission line (3), including an incoming line segment (31), a winding segment (32), and an outgoing line segment (33) connected in sequence. The direction extending from the incoming line segment (31) to the outgoing line segment (33) is the first extension direction; The incoming line segment (31) is located outside the first magnetic ring (1) and the second magnetic ring (2); One end of the winding segment (32) is connected to one end of the incoming line segment (31). The winding segment is composed of N turns of magnetic ring windings. Among them, after the winding segment (32) passes through the first magnetic ring (1) from the first face (11) of the first magnetic ring along the first extension direction, it then passes through the second magnetic ring (2) from the first face (21) of the second magnetic ring to form one turn of the magnetic ring winding, N≥1; The outgoing line segment (33) is located outside the first magnetic ring (1). One end of the outgoing line segment (33) is connected to the second end of the winding segment (32). The outgoing line segment (33) passes through the first magnetic ring (1) from the first face (11) of the first magnetic ring along the first extension direction; The number of turns of the transmission line passing through the second magnetic ring (2) is 1 less than the number of turns of the transmission line passing through the first magnetic ring (1), so as to reduce the change amount of the optimal suppression frequency point of the transmission line (3).

2. The magnetic ring set according to claim 1, wherein: The transmission line (3) includes a live wire and a neutral wire; Or, The transmission line (3) includes a live wire, a neutral wire, and an auxiliary wire, and the auxiliary wire includes a ground wire and / or a communication wire.

3. The magnetic ring winding set according to claim 2, wherein, Further comprising: A common mode choke (4); The common mode choke (4) is connected to the live wire of the outgoing line segment.

4. The magnetic ring set according to any one of claims 1-3, wherein: The first magnetic ring and the second magnetic ring are of the same type; And / or, the first magnetic ring and the second magnetic ring have the same optimal suppression frequency point.

5. The magnetic ring set according to any one of claims 1-4, wherein: The first magnetic ring is a nickel-zinc magnetic ring, a manganese-zinc ferrite magnetic ring, or a magnesium-zinc ferrite magnetic ring; And / or, the second magnetic ring is a nickel-zinc magnetic ring, a manganese-zinc ferrite magnetic ring, or a magnesium-zinc ferrite magnetic ring.

6. The magnetic ring set according to any one of claims 1-5, wherein: The first magnetic ring is a closed magnetic ring or a snap-on magnetic ring; And / or, the second magnetic ring is a closed magnetic ring or a snap-on magnetic ring.

7. The magnetic ring set according to any one of claims 1-6, wherein: The first magnetic ring (1) and the second magnetic ring (2) are arranged side by side.

8. A method for reducing electromagnetic interference of a transmission line, characterized in that, Comprising: Winding the first magnetic ring and the second magnetic ring with the transmission line to form the magnetic ring set according to any one of claims 1-7.

9. The method for reducing electromagnetic interference of a transmission line according to claim 8, wherein Further comprising: Adjusting the number of turns N of the magnetic ring windings in the magnetic ring set to change the optimal suppression frequency point of the magnetic ring set.

10. An air conditioner, characterized in that, Comprising the magnetic ring set according to any one of claims 1-7.

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