CN210778091U

CN210778091U - Double-winding inductor and filter circuit

Info

Publication number: CN210778091U
Application number: CN201921736911.5U
Authority: CN
Inventors: 兰五星
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-16
Filing date: 2019-10-16
Publication date: 2020-06-16
Anticipated expiration: 2029-10-16

Abstract

The utility model discloses a double-winding inductor and a filter circuit, belonging to the field of electromagnetic compatibility; the transformer specifically comprises a main winding and a secondary winding, wherein the main winding is electrically connected with a main circuit; the secondary winding is wound on the main winding, and an insulating layer is arranged between the secondary winding and the main winding; wherein, the head end and the tail end of the secondary winding are electrically connected to form a loop; in the main circuit, alternating noise passing through the main winding is blocked by self-induced electromotive force of the main winding, and a changing magnetic field generated by the alternating noise can also enable the secondary winding to generate induced current which generates heat in a loop of the secondary winding, so that the energy of the noise is finally consumed in the form of heating of the secondary winding; compared with the traditional inductor, the inductor only utilizes the blockage of the self-inductance electromotive force of the main winding to alternate clutter, and the anti-electromagnetic interference effect is obviously improved.

Description

Double-winding inductor and filter circuit

Technical Field

The utility model relates to an electromagnetic compatibility field especially relates to a duplex winding inductor and use its filter circuit.

Background

Electromagnetic Interference (EMI) refers to an Interference phenomenon generated after Electromagnetic waves and electronic components act, and includes two types, namely conduction Interference and radiation Interference. Conducted interference refers to coupling (interfering) signals on one electrical network to another electrical network through a conductive medium; the radiation interference means that an interference source couples (interferes) signals to another electric network through space, and in the design of a high-speed PCB and a system, a high-frequency signal line, pins of an integrated circuit, various connectors and the like can be radiation interference sources with antenna characteristics and can emit electromagnetic waves and influence the normal work of other systems or other subsystems in the system.

The existing commercial power is alternating current, and small accessories like a charger of a mobile phone or large electrical appliances such as household appliances or smart homes are directly connected with the commercial power; in the process of electrifying and using the electric appliances, the noise waves of the commercial power easily cause interference to electronic components in the electric appliances; the inductor is used as a basic element in the circuit and has the characteristics of direct current passing and alternating current blocking; generally, an inductor is arranged in a circuit to filter noise waves and reduce electromagnetic interference; however, the degree of electromagnetic interference filtering of the existing inductor is not strong, and sometimes in order to make the product meet the EMC certification requirement, additional time and effort are required to be made in the circuit design, which increases the difficulty of the circuit design.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects existing in the technology, the utility model provides a bifilar inductor, which utilizes the characteristics of bifilar to convert the induced magnetic field generated by the alternating clutter into induced current and then consumes the induced current in the form of heat; compared with the traditional filter inductor, the anti-electromagnetic interference effect is obviously improved!

In order to achieve the above object, the present invention provides a dual-winding inductor, which includes a main winding and a secondary winding, wherein the main winding is electrically connected to a main circuit; the secondary winding and the main winding are mutually inducted to form a mutual inductor group, and the head end and the tail end of the secondary winding are electrically connected to form a loop.

And the number of turns of the secondary winding coil is not less than 3.

The winding comprises a main winding, a winding core and a winding core, wherein the main winding is wound on the winding core, and the winding core is made of an insulating material; the secondary winding is wound around the primary winding in mutual inductance with the primary winding.

Wherein, the skeleton still is equipped with the inner chamber, and the inner chamber is equipped with the magnetic core.

The transformer comprises a main winding, a magnetic core and an insulating layer, wherein the main winding is wound on the magnetic core; the secondary winding is wound around the primary winding and is mutually inductive with the primary winding.

Wherein, the head and the tail of the secondary winding are directly connected through a wire to form a closed loop.

The head end of the secondary winding is connected with one end of the capacitor, and the other end of the capacitor is connected with the tail end of the secondary winding to form a closed loop.

In order to realize the above object, the utility model also provides a filter circuit, including rectifier bridge and bifilar inductor, the input of commercial power is received to the input of rectifier bridge, and output positive pole or negative pole are connected with the main winding, and the main winding is connected with external load.

In order to achieve the above object, the present invention further provides a dual-winding inductor, which includes a dual-winding inductor and a framework, wherein the main winding includes a first main winding and a second main winding, and the first main winding and the second main winding are symmetrically wound on the framework; the first secondary winding is wound on the first main winding, and the second secondary winding is wound on the second main winding; and the first main winding is electrically connected with the positive pole of the circuit, and the second main winding is electrically connected with the negative pole of the circuit.

In order to achieve the above object, the present invention further provides a filter circuit, which includes a rectifier bridge and a dual winding inductor; the input end of the rectifier bridge receives the input of commercial power, the positive pole of the output end is connected with the first main winding, and the first main winding is electrically connected with the positive pole of an external load; the negative electrode of the output end is connected with the second main winding, and the second main winding is electrically connected with the negative electrode of the external load. In order to realize the above object, the utility model also provides a filter circuit, including rectifier bridge and bifilar inductor, the input of commercial power is received to the input of rectifier bridge, and output positive pole or negative pole are connected with the main winding, and the main winding is connected with external load.

The utility model has the advantages that: the utility model comprises a main winding and a secondary winding, wherein the main winding is electrically connected with a main circuit; the secondary winding is wound on the main winding to form mutual inductance with the main winding, and an insulating layer is arranged between the secondary winding and the main winding; wherein, the head end and the tail end of the secondary winding are electrically connected to form a loop; in the main circuit, alternating noise passing through the main winding is blocked by self-induced electromotive force of the main winding, and a changing magnetic field generated by the alternating noise can also enable the secondary winding to generate induced current which generates heat in a loop of the secondary winding, so that the energy of the noise is finally consumed in the form of heating of the secondary winding; compared with the traditional inductor, the inductor only utilizes the blockage alternating noise of the self-induced electromotive force of the main winding, and the effect of resisting electromagnetic interference is obviously improved!

Drawings

Fig. 1 is a diagram of equivalent electronic components of the duplex winding filter inductor of the present invention;

fig. 2 is a structure diagram of the hollow inductor of the present invention;

fig. 3 is a differential mode filter circuit diagram of the present invention;

fig. 4 is a structural diagram of the double-winding filter inductor with a framework of the present invention;

fig. 5 is a structural diagram of the dual winding filter inductor with the framework and the magnetic core according to the present invention;

fig. 6 is a structural diagram of the frameless duplex-winding filter inductor with the magnetic core according to the present invention;

fig. 7 is an equivalent circuit diagram of the secondary winding circuit series capacitor of the present invention;

FIG. 8 is an equivalent circuit diagram of the series resistance of the secondary winding circuit of the present invention;

fig. 9 is a structural diagram of the dual winding filter inductor with the common mode secondary winding according to the present invention;

fig. 10 is a circuit diagram of the common mode filter of the present invention;

fig. 11 is a MEI test report of the present invention in which no secondary winding is provided on the zero line in the differential mode;

fig. 12 is an MEI test report of the present invention in which 1 winding turn is provided on the zero line during the differential mode;

fig. 13 is an MEI test report of the utility model in which a 3-turn winding is provided on the zero line during the differential mode;

fig. 14 is an MEI test report of the present invention in which 9 turns of secondary windings are provided on the zero line during the differential mode;

FIG. 15 is an MEI test report of the present invention without windings on the neutral line during common mode;

fig. 16 is an MEI test report of the utility model in which a 3-turn winding is provided on the zero line during common mode;

fig. 17 is a MEI test report of the common mode live wire of the present invention without windings;

fig. 18 is the MEI test report of the utility model discloses set up 3 windings on the live wire during common mode.

The main element symbols are as follows:

2. a rectifier bridge; 3. a capacitor; 4. a resistance; 11. a main winding; 12. a secondary winding; 13. a framework; 14. a magnetic core; 111. a first main winding; 112. a first secondary winding; 121. a second main winding; 122. and a second secondary winding.

Detailed Description

In order to make the present invention clearer, the present invention will be further described with reference to the accompanying drawings.

The EMC (electromagnetic Compatibility) is called Electro Magnetic Compatibility, which is defined as the ability of equipment and system to work normally in its electromagnetic environment without causing electromagnetic disturbance that anything in the environment cannot bear; secondly, the electromagnetic disturbance generated by the equipment cannot generate excessive influence, namely electromagnetic disturbance (EMI), on other electronic products.

With the development of electric and electronic technology, household electrical appliances are increasingly popularized and electronized, radio and television, post and telecommunications and computer networks are increasingly developed, and electromagnetic environments are increasingly complicated and deteriorated, so that the electromagnetic compatibility problem of electric and electronic products is increasingly emphasized by governments and manufacturing enterprises of various countries. Electromagnetic compatibility (EMC) of electronic and electric products is a very important quality index, which not only relates to the working reliability and the use safety of the products, but also can influence the normal work of other equipment and systems and is related to the protection problem of the electromagnetic environment; in order to standardize the electromagnetic compatibility of electronic products, all developed countries and part of developing countries set up electromagnetic compatibility standards; the electromagnetic compatibility standard is a basic requirement for enabling a product to normally work in an actual electromagnetic environment; that is, the product should at least meet the electromagnetic compatibility standard if put into production use, avoiding interference problems in actual use.

EMI comprises two types of conducted interference and radiated interference; a commonly used means for suppressing the radiation interference is to use magnetic beads, and an inductor is used for suppressing the conduction interference; the inductor comprises an inductance coil, wherein the inductance coil is formed by winding a lead and has a certain number of turns; the principle of the inductor for suppressing conducted interference is as follows: when current passes through the coil, a magnetic field is generated around the coil; when the current in the coil changes, the magnetic field around the coil also changes correspondingly, and the changed magnetic field can enable the coil to generate induced electromotive force (induced electromotive force) which is self-inductance; no matter how the direction of the current passing through the coil changes, the direction of the induced electromotive force generated by self induction is always opposite to the direction of the current flowing in the coil, so that the alternating current resistance effect is achieved; and the impedance value of the inductor coil increases as the frequency of the alternating current increases before reaching a maximum value; alternating current interference signals are changed into magnetic energy and heat energy to be consumed by electric energy when passing through the inductor, so that the interference signals with higher frequency can be inhibited, and the inhibiting effect of the inductor is better when the frequency is higher.

The conventional effective means for suppressing EMI is usually to use a common mode rejection inductor, that is, an inductor is connected in series between the ground line or other input/output lines, this inductor is called a common mode rejection inductor, one end of the common mode rejection inductor is connected to the ground line in the machine, the other end of the common mode rejection inductor is connected to a Y capacitor 3, and the other end of the Y capacitor 3 is connected to the ground. This is the most effective way to suppress conducted interference. However, the use of the Y capacitor 3 to suppress conducted interference has certain drawbacks, the existence of the Y capacitor 3 causes leakage current between the input line and the output line, the metal case with the Y capacitor 3 may cause electric shock to a user, if a non-Y scheme is adopted, it may cause difficulty to EMI design, how to effectively reduce EMI has become a difficult point in power circuit design, and it becomes a problem of headache for the industry.

The utility model discloses the people is according to the practice of the circuit design of practicing tens of thousands of times, still to tens of thousands of times, independently develops a duplex winding inductor, and the effect that this inductor restraines EMI far surpasss the effect that traditional inductance restraines EMI; by adopting the double-winding inductor provided by the utility model in the same circuit design, the electromagnetic compatibility of the whole circuit is obviously improved compared with the traditional inductor; this greatly reduces the difficulty of circuit design, and the problem of difficult EMI design from the level of basic electronic components, which is a major breakthrough in the industry!

Referring to fig. 1, the dual-winding inductor includes a main winding 11 and a secondary winding 12, the main winding 11 is used for electrically connecting with a main circuit; the secondary winding 12 is wound on the main winding 11 to form mutual inductance with the main winding 11, and an insulating layer is arranged between the secondary winding 12 and the main winding 11; wherein, the two ends of the secondary winding 12 are electrically connected to form a loop.

Referring to fig. 2, the main winding 11 is a hollow inductor formed by copper wire coils; the copper coil is bent into a spring shape by a copper wire, one end of the copper coil is electrically connected with the positive electrode of the output end of the main circuit, and the other end of the copper coil is connected with the positive electrode input end of the load; the secondary winding 12 is wound on the main winding 11, and the secondary winding 12 is only required to be enameled, so that the secondary winding 12 and the main winding 11 are mutually insulated; meanwhile, the two ends of the secondary winding 12 are electrically connected end to form a loop; when the output end of the main circuit outputs an alternating current interference signal, the alternating current interference signal flows through the main winding 11, the main winding 11 has the same function as the traditional inductor, namely, the alternating current interference signal is converted into magnetic energy and heat energy by the main winding 11 and is consumed, and the interference signal with higher frequency is inhibited; meanwhile, a variable magnetic field generated by an alternating current interference signal of the main winding 11 can generate induction current on the secondary winding 12; the induced current in the secondary winding 12 is again dissipated in the circuit in the form of heat; that is to say, the energy of the alternating current interference signal is divided into two parts for consumption, the first part is dissipated by the main winding 11 in the form of heat energy and magnetic energy, the second part is dissipated by the secondary winding 12 in the form of heat, compared with the traditional inductor, the loop of the secondary winding 12 is added, and the EMI suppression effect is greatly improved; the number of turns of the secondary winding 12 is greater than three, so that the secondary winding 12 can generate enough induced electromotive force in a changing magnetic field.

Example 1: the test product is a humidifier

Referring to fig. 2 and 3, the main circuit is a differential mode circuit; the main circuit comprises a rectifier bridge 2, the input end of the rectifier bridge 2 is connected with a mains supply, the positive electrode of the output end is connected with a main winding 11, the other end of the main winding 11 is connected with the positive electrode of an external load, and the negative electrode of the load is connected with the negative electrode output end of the rectifier bridge 2 to form a loop; testing to obtain the EMI values of the zero line under different frequency bands in the main circuit; wherein the values of EMI are shown in fig. 11-13; fig. 11 to 14 are the case where the sub-windings 12 are not added, the number of the sub-windings 12 is 1, the number of the sub-windings 12 is 3, and the number of the sub-windings 12 is 9, respectively; EMI test reports under 4 different conditions; in the tables of fig. 11 to 14, the abscissa is the frequency of the alternating current and the ordinate is the value of EMI; the straight line QV represents the standard peak value, AV represents the standard average value; the multi-segment line QV represents the actual test peak value, and the multi-segment line AV represents the actual test average value; wherein, the average value and the peak value actually measured in the industry are not higher than the standard value; comparing fig. 11 and 12, the number of secondary windings 12 is 1, and the measured peak and average values of MEI are substantially unchanged; comparing with fig. 13 again, when the number of the secondary windings 12 is 3, the measured peak value of EMI is slightly reduced, and the average value is basically unchanged; when the secondary winding 12 is 9, the measured peak value and peak value of EMI are obviously reduced; compared with no winding, the peak value is reduced by about 5dBuv, and the average value is reduced by about 10 dBuv; it can be known that after at least 3 turns of the secondary winding 12 are added, the value of MEI starts to be suppressed, and when the secondary winding 12 is 9 turns, an obvious suppression effect on EMI starts to be achieved; and the more the number of turns of the sub-winding 12, the better the suppression effect on EMI.

Referring to fig. 4, the dual-winding inductor provided by the present invention may further include a frame 13, the main winding 11 is wound on the frame 13, and the frame 13 is made of an insulating material; the framework 13 is usually made of plastics, bakelite and ceramics, and can be made into different shapes according to actual requirements; the preferred skeleton 13 adopts the ring form that plastics were made, and main winding 11 chooses the copper wire for use, and direct winding is on the ring, and secondary winding 12 chooses the enameled wire for use, and direct winding is on the copper wire.

In this embodiment, please refer to fig. 5, the frame 13 further has an inner cavity, and the inner cavity is provided with a magnetic core 14; the core 14 includes a core and a core; the magnetic core is made of nickel-zinc ferrite (NX series) or manganese-zinc ferrite (MX series) and has various shapes such as I shape, column shape, cap shape, E shape, pot shape and the like; the iron core material mainly comprises silicon steel sheets, permalloy and the like, and the shape of the iron core material is E-shaped; after the magnetic core 14 is inserted into the inner cavity, the magnetic field can be more tightly constrained around the inductance element, so that the inductance effect is achieved, and the effect of filtering interference signals is better.

Referring to fig. 5, in a first specific embodiment, the primary winding 11 is formed by winding a copper wire directly around a plastic ring, and the secondary winding 12 is formed by winding an enameled wire directly around the copper wire; the inner cavity of the circular ring is provided with a cylindrical magnetic material.

Referring to fig. 6, in a second embodiment, the magnetic core 14 is made of a cylindrical magnetic material; the main winding 11 is a copper wire wound on the magnetic core 14, and the secondary winding 12 is an enameled wire directly wound on the main winding 11.

In an electrical connection loop of the secondary winding 12, referring to fig. 7, in one aspect, the two ends of the secondary winding 12 are directly connected by a wire to form a closed loop; in another scheme, referring to fig. 8, due to the characteristics of the alternating current, the head end of the secondary winding 12 is connected to one end of the capacitor 3, and the other end of the capacitor 3 is connected to the tail end of the secondary winding 12 to form a closed loop.

Example 2:

referring to fig. 9 and 10, the main circuit is a working mode circuit; the main circuit comprises a rectifier bridge 2, the input end of the rectifier bridge 2 receives the input of commercial power, the positive pole of the output end is connected with a first main winding 111, and the first main winding 111 is electrically connected with the positive pole of an external load; the negative pole of the output end is connected with the second main winding 121, and the second main winding 121 is electrically connected with the negative pole of an external load; wherein, the number of turns of the secondary winding 12 is 3; the first main winding 111 and the second main winding 121 are directly wound on a circular ring made of plastic, the secondary winding 12 is an enameled wire, the first secondary winding 112 is an enameled wire and is directly wound on the first main winding 111, and the second secondary winding 122 is a second main winding 121 which is directly wound by the enameled wire; and a magnetic core 14 is arranged in the center of the circular ring.

Testing to obtain the EMI values of the zero line and the live line under different frequency bands in the main circuit; wherein the values of EMI are shown in fig. 15-18; fig. 15 to 18 are an EMI test report of the zero line without the secondary winding 12 added, an EMI test report of the zero line with 3 turns of the secondary winding 12 added, an EMI test report of the live line with no secondary winding 12 added, and an EMI test report of the live line with 3 turns of the secondary winding 12 added, respectively; in the tables of fig. 15 to 18, the abscissa is the frequency of the alternating current and the ordinate is the value of EMI; the straight line QV represents the standard peak value, AV represents the standard average value; the multi-segment line QV represents the actual test peak value, and the multi-segment line AV represents the actual test average value; wherein, the average value and the peak value actually measured in the industry are not higher than the standard value; comparing fig. 15 and 16, the measured peak and mean values of MEI on the zero line both decreased by about 5 dBuv; comparing again fig. 17 and 18, the measured peak and mean values of MEI on the fire line both decreased by about 5 dBuv; it can be seen that the secondary winding 12 has a significant effect of suppressing EMI; it can be seen from the combination of embodiment 1 that the effect achieved by 9 turns of the secondary winding 12 in embodiment 1 is equivalent to the EMI suppression effect achieved by 3 turns of the secondary winding 12 in this embodiment; the suppression effect after the addition of the magnetic core 14 can also be proved to be better! It is easy to conclude that the number of turns of the sub-winding 12 and the magnetic field strength in the sub-winding 12 are two important factors affecting the EMI suppression effect.

The utility model has the advantages that:

1. the utility model provides a duplex winding inductor, which utilizes the characteristics of duplex winding to convert the induced magnetic field generated by alternating clutter into induced current in the loop of secondary winding, and consumes the induced current in the form of heat; compared with the traditional filter inductor, the anti-electromagnetic interference effect is obviously improved;

2. the utility model provides a duplex winding inductance still includes the skeleton, and the main winding includes first main winding and second main winding, and first main winding and second main winding symmetry are twined on the skeleton; the first main winding is electrically connected with the anode of the circuit, and the second main winding is electrically connected with the cathode of the circuit; the filtering form of the common mode is formed, and the MEI effect is better than that of the differential mode filtering.

The above disclosure is only for the specific embodiments of the present invention, but the present invention is not limited thereto, and any changes that can be made by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A double-winding inductor is characterized by comprising a main winding and a secondary winding, wherein the main winding is electrically connected with a main circuit; the secondary winding and the main winding are mutually inducted to form a mutual inductor group, and an insulating layer is arranged between the secondary winding and the main winding; wherein the head and the tail of the secondary winding are electrically connected to form a loop.

2. The double-winding inductor of claim 1, wherein the number of secondary winding turns is not less than 3 turns.

3. The double-winding inductor according to claim 1, further comprising a bobbin, the main winding being wound around the bobbin, and the bobbin being an insulating material; the secondary winding is wound around the primary winding and is mutually inductive with the primary winding.

4. A bifilar inductor as claimed in claim 3, wherein the bobbin is further provided with an internal cavity, the internal cavity being provided with a magnetic core.

5. The bifilar inductor of claim 1, further comprising a magnetic core, the main winding being wound around the magnetic core with an insulating layer disposed therebetween; the secondary winding is wound around the primary winding and is mutually inductive with the primary winding.

6. The bifilar inductor of claim 1, wherein the ends of the secondary winding are directly connected by a wire to form a closed loop.

7. A bifilar inductor as claimed in claim 1, wherein the secondary winding head end is connected to one end of a capacitor, the other end of the capacitor being connected to the secondary winding tail end to form a closed loop.

8. A filter circuit, comprising a rectifier bridge and the dual-winding inductor as claimed in any one of claims 1 to 7, wherein the input end of the rectifier bridge receives the input of the commercial power, the positive or negative pole of the output end is connected with the main winding, and the main winding is connected with the external load.

9. A dual-winding inductor comprising the dual-winding inductor of claim 1, and further comprising a bobbin, wherein the main winding comprises a first main winding and a second main winding, and the first main winding and the second main winding are symmetrically wound on the bobbin; the first secondary winding is wound on the first main winding, and the second secondary winding is wound on the second main winding; and the first main winding is electrically connected with the positive pole of the circuit, and the second main winding is electrically connected with the negative pole of the circuit.

10. A filter circuit comprising a rectifier bridge and the double-winding inductor of claim 9; the input end of the rectifier bridge receives the input of commercial power, the positive pole of the output end is connected with the first main winding, and the first main winding is electrically connected with the positive pole of an external load; the negative electrode of the output end is connected with the second main winding, and the second main winding is electrically connected with the negative electrode of the external load.