CN201036112Y

CN201036112Y - Novel inductor for coil using magnetic shielding

Info

Publication number: CN201036112Y
Application number: CNU200720006127XU
Authority: CN
Inventors: 毛行奎
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2007-01-19
Filing date: 2007-01-19
Publication date: 2008-03-12
Anticipated expiration: 2017-01-19

Abstract

The utility model relates to a novel inductor adopting a magnetic shielding coil. The inductor comprises a magnetic core (5) with high permeability, a frame (6) covered outside the mid-column (51) of the magnetic core, and a coil (7) coiling on the frame. The magnetic core column of the magnetic core is provided with an air gap (8). The utility model is characterized in that the surface of the coil frame covered outside the mid-column of the magnetic core is plated with a layer of good conductor material (9) which is not closed to form a magnetic shielding layer. Based on that the wear of the magnetic core of the inductor can not be increased, the device can effectively reduce the eddy wear and the exotherm of an air gap when the inductor is in high frequency, and is beneficial to improve the power density and the efficiency of the inductor, in addition, the utility model has simple structure and convenient production.

Description

Coil adopts the novel inductor device of magnetic screen

Technical field

The utility model relates to magnetic element and makes the field, specially refers to the high frequency power magnetic element that is applied to electronic power converter.

Background technology

Inductor is born important function such as energy storage and filtering in electronic power converter, use very extensive.Its core structure both can adopt the powder core magnetic core of low magnetic permeability magnetic material, as iron-dust core, High-flux, powder core magnetic materials such as Kool-μ, MPP, also can adopt high magnetic permeability magnetic material to add the magnetic core of air-gap.

For the inductor that adopts powder core magnetic core, though its coil window magnetic field is more even, less and the powder core magnetic material of coil eddy current loss has low magnetic permeability and high saturation magnetic induction advantage when having high frequency, but because the high-frequency loss density of powder core magnetic material is bigger at present, when in the close Power Conversion applications of high frequency and big alternate current operation magnetic (as the inductor of resonant inductor and APFC etc.), to cause the rapid increase of loss and the inductor temperature rise of powder core magnetic core to increase greatly, limit of the application of this structure inductor in high frequency and the big close Power Conversion occasion of alternate current operation magnetic.

For adopting high magnetic permeability magnetic material to add the inductor of air-gap magnetic core, though high magnetic permeability magnetic material can adopt the less ferrite magnetic materials of loss density when the high frequency power application scenario, but because the magnetic field very inhomogeneous (coil window magnetic field such as Figure of description Fig. 2) of coil window, high frequency lower coil eddy current loss will sharply increase, and make this structure inductor also be subjected to certain restriction in the application of high frequency and the big close Power Conversion occasion of alternate current operation magnetic.Figure of description Fig. 1 is for being made of the inductor structure of magnetic core high magnetic permeability magnetic material and air-gap, it is made of magnetic core 1, skeleton 2 and coil 3, offers air-gap 4 on the core post 11 of magnetic core.Fig. 2 is the coil window magnetic flux distribution schematic diagram of Fig. 1 structure inductor, and 41 is main flux among the figure, and 42 is dispersing flux, and 43 are the bypass magnetic flux.As seen from Figure 2, this structure inductor causes coil eddy current loss very big because

magnetic flux

42,43 penetrates into sectioned coil conductor in the coil window during high frequency.

Therefore, be operated in the important topic that high frequency and the big AC magnetism inductor under close becomes power electronics HF power conversion area research and application.Solve this difficult problem, want on the one hand active development to be applicable to the powder core magnetic material of high frequency, as amorphous, nanocrystalline equimagnetic material, with the reduction core loss, but the high-frequency loss characteristic of these magnetic materials and price are also unsatisfactory at present; To start with from reducing the loss of coil high-frequency vortex on the other hand, as passing through design lines loop-shaped and magnetic core window shape, by introducing accurate distributed air gaps { as shown in Figure 3, the air gap 4 of Fig. 1 inductor in high frequency is divided into several small air gap 44}, or distributed air gaps { as shown in Figure 4, the air gap 4 usefulness low magnetic permeability magnetic materials 45 of Fig. 1 inductor in high frequency are replaced }, and the interlaced arrangement by air gap { as shown in Figure 5, the air gap 46 that air gap 4 usefulness of Fig. 1 inductor in high frequency is positioned at the differing heights plane replaces } etc., the coil eddy current loss of inductor in the time of all can reducing high frequency to a certain extent.But these methods are all making the manufacturing process of coil and magnetic core complicate in varying degrees, often all need skeleton or magnetic core according to requirement of client design or manufacturing nonstandardized technique, and their limitation is all arranged.In addition, the magnetic material 47{ that adds a low magnetic permeability between core post that also can be by opening air gap 4 at Fig. 1 inductor in high frequency and coil is as shown in Figure 6 }, to reduce its coil high-frequency vortex loss.

Because high frequency power inductor coil eddy current loss mainly is to be caused by high frequency dispersing flux that enters its coil window and bypass magnetic flux sectioned coil conductor, therefore the key that reduces coil eddy current loss is to reduce to enter the high frequency magnetic flux of coil window, and the coil-conductor area that reduces the high frequency magnetic flux cutting that is entered coil window.

The utility model content

The purpose of this utility model is the not closed electric good conductor material of a kind of coil rack overlay coating is provided so that coil adopts the novel inductor device of magnetic screen, this device can not only be on the basis that does not increase the inductor core loss, coil eddy current loss when effectively reducing out air gap inductance device high frequency, and have characteristics simple in structure, that be convenient to produce.

The technical solution of the utility model is to constitute like this, comprise high magnetic permeability magnetic core, be sheathed on the skeleton of magnetic core center pillar periphery and be wound in coil on the skeleton, offer air-gap on the core post of magnetic core, it is characterized in that: the inc electric good conductor material of plating one deck on the coil rack surface that is sheathed on magnetic core center pillar periphery, for coil-conductor provides a magnetic masking layer.

The utility model has been introduced the magnetic masking layer that is made of electric good conductor material owing to (the inside and outside surface that comprises coil rack) last plating inc electric good conductor material of one deck (as materials such as copper, aluminium) on the coil rack surface.The introducing of this screen makes the high frequency magnetic flux that enters the inductor coil window reduce, thereby has reduced the magnetic field of the coil region of coil window, has significantly reduced the high-frequency vortex loss and the inductor temperature rise of coil, has improved the performance of inductor.Simultaneously, because the magnetic flux in the inductor core is uninfluenced, so the high-frequency vortex loss of magnetic core is increased.In addition,, do not need standardized magnetic core is carried out special design or processing and fabricating owing to only need the inc electric good conductor material of coating on coil rack, therefore have simple in structure, the characteristics of being convenient to produce.

Description of drawings

Fig. 1 is existing a kind of inductor structure figure, the inductor structure figure that serves as reasons and concentrate air-gap and high magnetic permeability magnetic core to constitute;

Fig. 2 is the coil window magnetic flux distribution schematic diagram of Fig. 1;

Fig. 3 adopts the inductor structure figure of accurate distributed air gaps for Fig. 1;

Fig. 4 adopts the inductor structure figure of distributed air gaps for Fig. 1;

Fig. 5 adopts the inductor structure figure of staggered air gap for Fig. 1;

Fig. 6 is for adding the inductor structure figure of low magnetic permeability magnetic material between the core post of opening air gap and coil;

Fig. 7 is inductor structure figure of the present utility model;

Fig. 8 is the A-A profile of Fig. 7;

Fig. 9 is Fig. 1 and two kinds of structure inductors of Fig. 7 magnetic field profile along inductor inner coil conductive surface, among the figure: 10 magnetic field profiles for the inner coil conductive surface that adopts the utility model inductor, 11 for not adopting the utility model but the magnetic field profile of the identical single air gap inductance device inner coil conductive surface of parameter;

Figure 10 is the inductor structure figure of the utility model magnetic core when adopting accurate distributed air gaps;

Inductor structure figure when Figure 11 is the utility model magnetic core employing interlaced arrangement air gap.

Embodiment

Novel inductor device of the present utility model, comprise high magnetic permeability magnetic core 5, be sheathed on the skeleton 6 of magnetic core center pillar 51 peripheries and be wound in coil 7 on the skeleton, offer air-gap 8 on the core post of magnetic core, it is characterized in that: the inc electric good conductor material 9 of plating one deck on the coil rack surface that is sheathed on magnetic core center pillar periphery, to form magnetic masking layer.

Above-mentioned electric good conductor material is copper or aluminium.Be plated in the lip-deep electric good conductor layer of the coil rack that is sheathed on magnetic core center pillar periphery and offer isolation seam road 91 so that magnetic masking layer is not closed.

The structure of the utility model embodiment such as Fig. 7, shown in Figure 8,5 is the magnetic core of high-permeability material among the figure, 8 is the air-gap of magnetic core, 6 is coil rack, 9 inc electric good conductor materials (outer surface that only is plated on coil rack with electric good conductor material in the schematic diagram is an example) for being plated on the coil rack surface.In this structure, by the magnetic masking layer of a shielding high frequency magnetic field is provided for the coil-conductor in the inductor coil window at coil rack overlay coating electricity good conductor material, this just makes that the magnetic flux (comprising dispersing flux and bypass magnetic flux) that enters coil window reduces greatly, thereby reduced the eddy current loss of coil-conductor, as shown in Figure 9,10 Distribution of Magnetic Field is much more even than 11.At this moment, can bring extra high-frequency vortex loss though be plated on the magnetic masking layer itself that constitutes by inc electric good conductor material on the coil rack, but can be by this magnetic masking layer of appropriate design (comprising material, thickness, width, segments), feasible eddy current loss ratio because of the magnetic masking layer that it increased is much smaller because of the coil eddy current loss that it reduced, thereby effectively reduces the coil eddy current loss that high frequency is driven the air gap inductance device generally.

Since during high frequency the inductor coil conductor often adopt the line footpath thinner in line (twisted wire) or relatively thinner Copper Foil now, this moment is much smaller for the eddy current loss that the extra high-frequency vortex loss ratio coil-conductor that magnetic masking layer increased in this new structure is reduced, and the magnetic masking layer thickness of design is often very thin.Adopt the technology of the electric good conductor material of plating, then can guarantee the exploitativeness of this utility model so that the magnetic masking layer in the utility model structure can accurately be processed into the thickness of design.And the electric good conductor material technology of plating is very ripe on the coil rack of insulation.

The inc electric good conductor material that is plated on the coil rack surface should be looked concrete application along the segments that the core post circumferencial direction is divided, and can be determined (being divided into four fragments in the structure chart of Fig. 7) by design.Though when the electric good conductor material that is plated on the coil rack surface is closure, also can be the effect that coil-conductor plays the shielding high frequency magnetic field, but electric good conductor material that should closure will cause inductor to burn because of short circuit simultaneously also for inductor provides a closed short-circuited conducting sleeve.So, must guarantee that the electric good conductor material that is plated is inc implementing to add man-hour.

The magnetic core of novel inductor device of the present utility model also can adopt accurate distributed air gaps in Fig. 3 structure and the staggered air gap in Fig. 5 structure except the single air gap that adopts Fig. 7 example, as Figure 10, Figure 11, but should not adopt distributed air gaps in Fig. 4 structure.

Coil eddy-current loss and the temperature rise of inductor when the utility model can not only effectively reduce high frequency, and can not increase the magnetic core damage Consumption is conducive to improve power density and the efficient of inductor, has in addition simple in structurely, and the characteristics of being convenient to produce have very Big application value.

Claims

1. a coil adopts the novel inductor device of magnetic screen, comprise high magnetic permeability magnetic core (5), be sheathed on the peripheral skeleton (6) of magnetic core center pillar (51) and be wound in coil (7) on the skeleton, offer air-gap (8) on the core post of magnetic core, it is characterized in that: the plating inc electric good conductor material of one deck (9) on the coil rack surface that is sheathed on magnetic core center pillar periphery, for coil-conductor provides a magnetic masking layer.

2. coil according to claim 1 adopts the novel inductor device of magnetic screen, it is characterized in that: the electric good conductor layer that is plated on the coil rack surface is provided with isolates the seam road.

3. coil according to claim 1 and 2 adopts the novel inductor device of magnetic screen, and it is characterized in that: described electric good conductor material is copper or aluminium.