Small-sized common-mode inductor adopting two groups of relay coils

Abstract

The invention discloses a small common mode inductor adopting two groups of relay coils, which comprises a first winding, a second winding, a magnetic core, a first relay coil, a second relay coil, bakelite, a first input port, a second input port, a first winding connecting port, a second winding connecting port, a relay coil first access port and a relay coil second access port, a first output port; and a second output port. By adopting the technology of two groups of combined relay coils, the common mode inductor has the advantages of small size, easiness in assembly and the like, can be applied to power electronic equipment such as a switching power supply, an inverter, a relay and a converter, and particularly solves the EMI problem of small portable electronic products.

Description

Technical Field

[0001] The invention belongs to the technical field of common mode inductors, and relates to a miniaturized common mode inductor, and in particular to a miniaturized common mode inductor using two groups of relay coils. Background Art

[0002] As electronic devices become more and more complex and the operating frequency increases, EMI problems become more serious. Common-mode inductors use their special structure, such as two windings symmetrically wound on the magnetic core, to offset the magnetic field generated by the common-mode current, thereby suppressing electromagnetic noise. The magnetic fields generated by the common-mode current in the magnetic core are superimposed on each other, and the inductor presents high impedance, thereby attenuating common-mode noise. The magnetic fields generated by the differential-mode current (useful signal or power current) cancel each other out, and the inductor presents low impedance, which hardly affects normal signal transmission. At present, traditional winding common-mode inductors are commonly used in industrial applications. The inductor is made by winding symmetrical copper wire or other wires on a magnetic core or coreless. This method is suitable for various types of common-mode inductors, which are widely used from low frequency to high frequency. With the increasing application of portable devices, automotive electronics or high-frequency power supplies, the miniaturization of common-mode inductors is an inevitable requirement for the current electronic devices to develop towards light, thin, short and high integration, especially in portable devices (such as smart phones, wearable devices), high-frequency power supplies (such as GaN fast charging) and high-density PCB design. The driving factors for miniaturization are mainly equipment space limitations, high-frequency requirements, and cost and lightweight. The key technical paths for miniaturization can be divided into five categories: 1. innovation of magnetic core materials; 2. optimization of winding structure; 3. high-frequency design; 4. integration and modularization; 5. advanced manufacturing process. Considering the trade-off between performance and volume, heat dissipation, mechanical strength and reliability, and cost control, the miniaturization of common-mode inductors is a technical difficulty in industrial production. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a small common-mode inductor with high inductance, easy assembly and low cost using two sets of relay coils without increasing the external dimensions, in view of the defects of the existing technology of traditional winding common-mode inductors.

[0004] The technical solution adopted by the present invention to solve its technical problem is to construct a small common-mode inductor using two groups of relay coils, including: a first winding, a second winding, a magnetic core, a first relay coil, a second relay coil, bakelite, a first input port, a second input port, a first winding connection port, and a second winding connection port; the first winding and the second winding are both spirally wound on the magnetic core and have a horizontally symmetrical structure; the lower end connector of the first winding is the first input port, the upper end connector of the first winding is the first winding connection port, and the first winding connection port is connected to the first relay coil; the lower end connector of the second winding is the second input port, the upper end connector of the second winding is the second winding connection port, and the second winding connection port is connected to the second relay coil; the first relay coil and the second relay coil share the bakelite, and the internal windings of the first relay coil and the second relay coil are both parallel and pass through the same bakelite.

[0005] In the small common-mode inductor using two groups of relay coils described in the present invention, the first relay coil is composed of a first access port of the relay coil, a winding passing through the left side of the bakelite, and a first output port, and the second relay coil is composed of a second access port of the relay coil, a winding passing through the right side of the bakelite, and a second output port; the first winding connection port is connected to the first access port of the relay coil, and the second winding connection port is connected to the second access port of the relay coil.

[0006] In the small common-mode inductor using two groups of relay coils described in the present invention, the left winding and the right winding passing through the bakelite each include at least three turns of winding.

[0007] In the small common-mode inductor using two sets of relay coils described in the present invention, the bakelite and the windings of the first relay coil and the second relay coil located in the bakelite are divided into two and designed into a combined structure of a plug and a socket.

[0008] In the small common-mode inductor using two groups of relay coils described in the present invention, the bakelite includes an upper bakelite and a lower bakelite, the upper bakelite and the convex relay coil winding passing through it constitute a plug, and the lower bakelite and the concave relay coil winding passing through it constitute a socket, and when the plug and the socket are disconnected, the first relay coil and the second relay coil are installed in the small common-mode inductor.

[0009] In the small common-mode inductor using two groups of relay coils described in the present invention, after the first relay coil and the second relay coil are combined, the plug formed by the winding of the convex relay coil is just inserted into the socket formed by the winding of the concave relay coil, and the upper bakelite and the lower bakelite are integrated, so that the windings of the first relay coil and the second relay coil in the upper bakelite and the lower bakelite are connected.

[0010] In the small common-mode inductor using two groups of relay coils described in the present invention, the two groups of relay coils make full use of the space near the axis of the inductor. When it is inconvenient for the winding machine to wind near the axis without increasing the extra size, the number of winding coils is increased near the axis of the inductor through the relay coils, thereby increasing the inductance of the common-mode inductor and realizing the miniaturization of the common-mode inductor.

[0011] In the small inductor using two sets of relay coils described in the present invention, the present invention not only realizes the miniaturization of the inductor size, but also facilitates assembly. At the same time, since bakelite is introduced near the axis of the inductor to facilitate heat dissipation, good heat dissipation performance is also a beneficial effect of the small inductor. In short, the inductor can meet the design requirements of small power electronic systems and can be applied to power electronic equipment such as switching power supplies, inverters, relays and converters. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0013] Figure 1 This is a top view of the common mode inductor before the relay coil is introduced;

[0014] Figure 2 A top view of the structure of two groups of relay coils proposed according to the present invention;

[0015] Figure 3 A three-dimensional view of the structure of two groups of relay coils proposed according to the present invention;

[0016] Figure 4 It is a cross-sectional side view of the structure of two groups of relay coils proposed according to the present invention;

[0017] Figure 5 A top view of a complete small common-mode inductor using two sets of relay coils according to the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] In order to realize a small common mode inductor using two sets of relay coils, the present invention adopts a combined relay coil technology, and its specific design principle is as follows:

[0020] 1. The principle of miniaturization of common-mode inductors achieved by combined relay coil technology.

[0021] The present invention aims to solve the problem that existing common-mode inductors are difficult to wind near the center axis using winding machines. There are currently two solutions: 1. Wasting the center axis space of the common-mode inductor by directly winding the wire in spirals near the circumference of the toroidal core; 2. Winding the wires manually near the center axis. The former wastes the precious space of the common-mode inductor, while the latter has high labor costs and the winding near the center axis is irregular. The present invention adopts a combined relay coil technology to fully utilize the redundant space near the center axis to increase the number of winding coils. Figure 1 As shown, for the common mode inductor before the relay coil is introduced, there is space at the upper fan-shaped position and the central axis position in the figure. The present invention uses these two spaces to place a combined relay coil with two sets of relay windings. To distinguish the two sets of windings, white represents the first winding and black represents the second winding. Figure 2 As shown, for Figure 1 At the upper middle fan-shaped position and the center axis position, two groups of relay coils are wound in parallel. The first group of relay coils has 3 turns of relay coils on the left side of the magnetic core, and the second group of relay coils has 3 turns of relay coils on the right side of the magnetic core. At the same time, these two groups of relay coils pass through the same bakelite at the center axis position. To distinguish the two groups of relay coils, white represents the first relay coil and black represents the second relay coil. Figure 2 The two lead-out windings at the bottom serve as a pair of output ports of the common-mode inductor. Since the bakelite in the schematic diagram has a total of 6 turns of relay coils, and each set of relay coils has a total of 3 turns, the inductance on the left and right sides of the common-mode inductor increases by (n+3) compared to the inductance value before the introduction of the relay coils. 2 / n 2 times, where n is the number of turns of the single-sided inductor before the introduction of the relay coil. In other words, the increase in inductance is achieved without increasing the external size of the inductor, which is equivalent to achieving the miniaturization of the inductor. Figure 3 and Figure 4 As shown, in order to facilitate assembly, the bakelite located at the central axis position and the winding inside it are divided into two parts and designed into a plug and socket structure. The 6 turns of winding passing through the bakelite in the figure are broken into two parts, which are respectively used to realize the plug and socket connected to the two sections of bakelite. During the product production process, the 6 turns of winding passing through the bakelite should be marked with colors for easy docking.

[0022] The purpose of the present invention is to overcome the shortcomings of the prior art - when it is inconvenient for a winding machine to wind near the center axis of the inductor, by adopting a combined relay coil technology, the redundant space near the center axis is fully utilized to increase the number of winding coils, thereby achieving miniaturization of the wound inductor.

[0023] The present invention not only realizes a small-sized common-mode inductor, but also facilitates assembly, which is also a beneficial effect of the common-mode inductor. The common-mode inductor has the advantages of small size and easy assembly, and can be applied to power electronic devices such as switching power supplies, inverters, relays and converters, especially to solve the EMI problem of small portable electronic products.

[0024] The present invention will be further described below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to be limiting to the present invention.

[0025] In order to clearly describe the present invention, Figure 5 It is a complete top view of a small common-mode inductor using two groups of relay coils proposed by the present invention, a small common-mode inductor using a relay coil, including: a first winding 1, a second winding 2, a magnetic core 3, a first relay coil 4, a second relay coil 5, bakelite 6, a first input port 1a, a second input port 2a, a first winding connection port 1b, a second winding connection port 2b, a first access port 4a of the relay coil, a second access port 5a of the relay coil, a first output port 4b, and a second output port 5b.

[0026] The first winding 1 and the second winding 2 are both spirally wound on the magnetic core 3, presenting a horizontally symmetrical structure; the lower end connector of the first winding 1 is the first input port 1a, the upper end connector of the first winding 1 is the first winding connection port 1b, and the first winding connection port 1b is prepared to be connected to the first access port 4a of the relay coil; the lower end connector of the second winding 2 is the second input port 2a, the upper end connector of the second winding 2 is the second winding connection port 2b, and the second winding connection port 2b is prepared to be connected to the second access port 5a of the relay coil; the first relay coil 4 and the second relay coil 5 share the bakelite 6, and their internal windings all pass through the same bakelite 6 in parallel, the first relay coil 4 is composed of the first access port 4a of the relay coil, the 3 turns of winding passing through the left side of the bakelite 6, and the first output port 4b, and the second relay coil 5 is composed of the second access port 5a of the relay coil, the 3 turns of winding passing through the right side of the bakelite 6, and the second output port 5b.

[0027] Furthermore, the bakelite 6 and the winding therein are divided into two and designed into a combined structure of a plug and a socket. The internal conditions of the first relay coil 4 and the second relay coil 5 before assembly are as follows: Figure 3As shown, it reflects the state of the plug and socket composed of the bakelite 6 and the internal winding before assembly. The bakelite 6 is divided into two parts, the upper bakelite 6a and the lower bakelite 6b. The upper bakelite 6a and the 6 turns of convex relay wire passing through it constitute the plug, and the lower bakelite 6b and the 6 turns of concave relay wire passing through it constitute the socket. When the plug and the socket are disconnected, it is convenient to install the first relay coil 4 and the second relay coil 5 into the inductor.

[0028] Furthermore, the internal conditions of the first relay coil 4 and the second relay coil 5 after assembly are as follows: Figure 4 As shown, it reflects the state of the plug and the socket after assembly. After the first relay coil 4 and the second relay coil 5 are combined, the 6-turn convex relay winding plug is just inserted into the 6-turn concave relay winding socket, and the upper and lower parts of the bakelite are just integrated, and the windings in the bakelite are all connected.

[0029] Further, when the plug and socket are assembled, return to Figure 5 , just connect the first access port 4a of the relay coil to the first winding connection port 1b, and connect the second access port 5a of the relay coil to the second winding connection port 2b, and the entire common mode inductor can work normally.

[0030] The two groups of relay coils implemented according to the above embodiment need to be separately processed into plug and socket shapes according to the size of the common-mode inductor. The material of the first relay coil 4 and the second relay coil 5 is the same as the material of the first winding 1 and the second winding 2 of the common-mode inductor. The magnetic core 3 is made of ferrite, and the bakelite 6 is made of insulating and heat-dissipating phenolic plastic.

[0031] The small common-mode inductor using two sets of relay coils in the embodiment of the present invention has good size advantages and easy assembly characteristics. The inductor can meet the design requirements of small power electronic systems and can be used in power electronic devices such as switching power supplies, inverters, relays and converters, especially small portable high-frequency electronic products, and is worthy of promotion. The present invention includes but is not limited to the above-mentioned implementation schemes. Under the conception of the present invention, those skilled in the art can make different deformations and substitutions without departing from the principle of the present invention, such as the position of the relay coil, changing the annular magnetic core to other shapes, and using other metal or plastic materials. These deformations and substitutions also fall within the scope of protection of this patent.

[0032] Although the present invention is described by specific embodiments, it should be understood by those skilled in the art that various changes and equivalent substitutions may be made to the present invention without departing from the scope of the present invention. In addition, various modifications may be made to the present invention for specific situations or materials without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all implementation methods falling within the scope of the claims of the present invention.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A small common mode inductor using two sets of relay coils, characterized in that: include: A first winding, a second winding, a magnetic core, a first relay coil, a second relay coil, bakelite, a first input port, a second input port, a first winding connection port, and a second winding connection port; the first winding and the second winding are both spirally wound on the magnetic core and have a horizontally symmetrical structure; the lower end connector of the first winding is the first input port, the upper end connector of the first winding is the first winding connection port, and the first winding connection port is connected to the first relay coil; the lower end connector of the second winding is the second input port, the upper end connector of the second winding is the second winding connection port, and the second winding connection port is connected to the second relay coil; the first relay coil and the second relay coil share the bakelite, and the internal windings of the first relay coil and the second relay coil are both parallel and pass through the same bakelite.

2. The small common mode inductor using two sets of relay coils according to claim 1 is characterized in that: The first relay coil is composed of a first access port of the relay coil, a winding passing through the left side of the bakelite, and a first output port, while the second relay coil is composed of a second access port of the relay coil, a winding passing through the right side of the bakelite, and a second output port; the first winding connection port is connected to the first access port of the relay coil, and the second winding connection port is connected to the second access port of the relay coil.

3. The small common mode inductor using two sets of relay coils according to claim 2 is characterized in that: The left winding and the right winding passing through the bakelite each include at least three turns of winding.

4. The small common mode inductor using two sets of relay coils according to claim 2 is characterized in that: The bakelite and the windings of the first relay coil and the second relay coil located in the bakelite are divided into two and designed into a combined structure of a plug and a socket.

5. The small common mode inductor using two sets of relay coils according to claim 4 is characterized in that: The bakelite includes an upper bakelite portion and a lower bakelite portion, wherein the upper bakelite portion and the winding wire of the convex relay coil passing through it constitute a plug, and the lower bakelite portion and the winding wire of the relay coil passing through it constitute a socket, and when the plug and the socket are disconnected, the first relay coil and the second relay coil are installed in the small common mode inductor.

6. The small common mode inductor using two sets of relay coils according to claim 5, characterized in that: After the first relay coil and the second relay coil are combined, the plug formed by the winding of the convex relay coil is just inserted into the socket formed by the winding of the concave relay coil, and the upper bakelite and the lower bakelite are integrated into one, so that the windings of the first relay coil and the second relay coil in the upper bakelite and the lower bakelite are connected.

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