CN111817303A - Circuit and method for improving power quality of power grid - Google Patents

Circuit and method for improving power quality of power grid Download PDF

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Publication number
CN111817303A
CN111817303A CN202010874966.3A CN202010874966A CN111817303A CN 111817303 A CN111817303 A CN 111817303A CN 202010874966 A CN202010874966 A CN 202010874966A CN 111817303 A CN111817303 A CN 111817303A
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magnetic
coil
circuit
core
magnetic core
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CN111817303B (en
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李昌骏
郭健
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Golden Scorpion Co ltd
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Golden Scorpion Co ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01Arrangements for reducing harmonics or ripples
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/34Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/34Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F2027/348Preventing eddy currents
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40Arrangements for reducing harmonics

Abstract

The invention discloses a circuit and a method for improving the electric energy quality of a power grid, and the circuit comprises a power grid input terminal, a rectifying circuit, a power factor correction circuit, a high-frequency inverter circuit and an output terminal which are connected in sequence, wherein a control circuit is in control connection with the rectifying circuit, the power factor correction circuit and the high-frequency inverter circuit, the high-frequency inverter circuit comprises a magnetic core and a coil which are used for magnetic coupling, the coil is wound on an insulating structure, and one part of the magnetic core is arranged in a hollow channel of the insulating structure; the core and coil arrangement is such that a portion of the magnetic flux cuts the coil and a portion of the shunt magnetic cuts the coil within the core window to reduce eddy current losses. Under the condition that the number of turns of the coil is not changed, the magnetic flux leakage utilization rate of the magnetic core is improved, the distance between the coil and the magnetic core is increased, or the width of an air gap on the magnetic core is reduced, so that the magnetic flux leakage reduction device can be applied to the fields of photovoltaic grid connection, switching power supplies and the like, and the harmonic wave of a power grid is reduced, or the ripple is adjusted, the reactive power is adjusted, and.

Description

Circuit and method for improving power quality of power grid
Technical Field
The invention relates to a circuit and a method for improving the power quality of a power grid, in particular to a circuit and a method for improving the power quality of the power grid, which have low harmonic current and small pollution to the power grid, can be applied to the fields of photovoltaic grid connection, switching power supplies and the like, and can reduce the harmonic wave of the power grid or adjust the ripple, adjust the reactive power and the like.
Background
Along with the development of national economy, power converters are applied more and more widely, the capacities of inverter devices and rectifier devices used by equipment are larger and larger, the quantity of the inverter devices and the rectifier devices is more and more, large-capacity nonlinear load equipment generates a large amount of higher harmonic current to be injected into a power grid, the waveform of the power grid is distorted, the quality and the reliability of power supply are reduced, and the economic operation of the power supply and the electric equipment is threatened.
The large-capacity nonlinear load device mainly comprises: thyristor rectifier power supplies used in great quantities in the metallurgical, chemical and mining sectors; variable frequency speed control devices used in industry in large quantities; the electric railway adopts a locomotive powered by alternating current single-phase rectification; household appliances (televisions, refrigerators, washing machines, electronic energy-saving lamps), and the like. The capacity of an arc furnace for steel making is continuously expanding, and an arc furnace and a contact welding apparatus which are widely used in production, a submerged arc furnace, a ferrosilicon furnace, an intermediate frequency furnace, a high frequency furnace, and the like are also nonlinear power loads. The operation and use of the equipment enable the harmonic waves of the power grid to be more and more, the harmonic waves can form radiation and conduction along the line, the power grid is polluted, and the application of electronic equipment is influenced.
The problem of reactive compensation is a very important and typical problem in the operation of power distribution networks. Taking illumination as an example, a high pressure sodium lamp is the most dominant light source for road lighting. The bulb electric appliance of the general high-power special light supplement lamp has the characteristics that the tube pressure range is 175-.
The ballast is an indispensable control element for normal work of loads such as light supplement and illumination, and is connected in series in a circuit to limit lamp current so as to avoid burning out a bulb. An effective form of inductive ballast is inductive in nature with a very low intrinsic power factor of about 0.06, and a series circuit power factor of about 0.45 when connected in series with a sodium lamp. Such a low power factor will increase the power loss and voltage drop of the power supply line, affecting the luminous efficiency of the light source. The increased inductance results in larger device size, increased harmonics, and increased cost.
Generally, a load can only be used under a certain rated voltage, and power supplies need to be converted when the load is connected due to different power utilization voltages of different countries and regions in the world so as to adapt to different loads. Generally, a power conversion device also needs to be used under a certain rated voltage, when the power voltage is higher, a large amount of energy consumption is generated, especially when the power voltage is ultrahigh, the energy consumption is larger, and generally, the power conversion device of one model can not meet the voltage requirements of different countries; this usually requires different conversion means for different voltages, increasing production costs. Because the power quality of different areas is different, and too high or too low voltage also affects the efficiency of the power conversion device, affects the normal work of the load and further deteriorates the quality of the power grid, the cost can be reduced and the power quality of the power grid can be improved by manufacturing the switching power supply which can be connected to different power supply voltages, and a user does not need to select the switching power supply when using the switching power supply.
In summary, the magnetic element is an important part of power electronic technology, and plays roles in transferring energy, storing energy, filtering, isolating and the like. As a key component accounting for 30% -50% of the total loss of the circuit, the research works such as loss test, loss calculation, optimization design and the like of the magnetic element are particularly important. A general switching power supply circuit includes an inductor, and a coil and an iron core of the inductor have loss during power conversion to reduce conversion efficiency, and increase the number of turns of the coil or use a more expensive magnetic core to reduce energy loss and improve conversion efficiency, but the size is increased and the cost is increased.
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects in the prior art, and provide a circuit for improving the power quality of a power grid, wherein the circuit reduces the loss to the maximum extent, has high power conversion efficiency and low harmonic current under the condition of not increasing the volume, and can improve the power quality of the power grid.
The invention also aims to provide a method for improving the electric energy quality of a power grid, which greatly improves the energy conversion efficiency per unit volume and reduces harmonic waves without changing the winding and the number of turns of a coil by improving the magnetic leakage flux utilization rate of a magnetic core and reducing magnetic induction and leakage induction loss.
In order to solve the technical problems, the invention adopts the technical scheme that:
the power grid inverter comprises a power grid input terminal, a rectifying circuit, a power factor correction circuit, a high-frequency inverter circuit and an output terminal which are connected in sequence, wherein a control circuit is in control connection with the rectifying circuit, the power factor correction circuit and the high-frequency inverter circuit, the high-frequency inverter circuit comprises a magnetic core and a coil which are used for magnetic coupling, the coil is wound on an insulating structure, and one part of the magnetic core is arranged in a hollow channel of the insulating structure; the core and coil arrangement is such that a portion of the magnetic flux cuts the coil and a portion of the shunt magnetic cuts the coil within the core window to reduce eddy current losses.
In the present invention, the leakage flux cuts the coil within the core window to reduce eddy current losses.
In the invention, a first distance is arranged between at least part of the coil and the window end face of the magnetic core.
In the invention, a first distance is reserved between the channel wall of the hollow channel of the insulation structure and the window end face of the magnetic core.
In the invention, a first distance is respectively reserved between the coil and two end faces of the magnetic core window through the first wall and the second wall which are opposite to each other of the hollow channel of the insulating structure.
In the invention, a second distance is arranged between the coil and the left end face and the right end face of the middle magnetic column respectively corresponding to the coil through the opposite third wall and the fourth wall of the hollow channel of the insulating structure.
In the invention, a first distance is respectively arranged between the first wall and the second wall of the hollow channel of the insulating structure, which are opposite to each other, and two end faces of the window of the magnetic core, and the first distance is 1/3-1/6 of the height of the magnetic core.
In the invention, the air gaps in the magnetic core are n air gaps arranged at intervals, n is greater than or equal to 2, and the sum of the widths of the n air gaps is equal to the width of the air gap when the magnetic core is provided with one air gap, so that the eddy current loss is reduced.
In the present invention, the magnetic core and the coil for magnetic coupling satisfy the following formula:
Figure 323265DEST_PATH_IMAGE001
where r is a radius of the core or a radius of a center pillar of the core, and is a width of the air gap, d is a distance between the coil and the core, K is a reduced value of a magnetic flux of the core, γ is a reduced value of a fringe magnetic flux loss, and M is an effective reduced value of the magnetic flux.
The invention also comprises a method for improving the power quality of the power grid by adopting the circuit, which comprises the following steps: the high-frequency inverter circuit is characterized in that a magnetic core and a coil in the high-frequency inverter circuit are arranged as a part of a bypass magnetic flux cutting winding to reduce eddy current loss.
After the technical scheme is adopted, compared with the prior art, the invention has the following beneficial effects.
Under the condition of not changing the number of turns of the coil, the invention increases the inductance by reducing the eddy current loss without increasing the volume and the cost, and only an inductor is selected according to the minimum inductance, so that the same number of turns of the coil can greatly improve the suppression of the inductance to the harmonic wave, reduce the harmonic wave of a power grid and improve the quality of the electric energy of the power grid.
The inductance of the inductor is greatly improved by reducing the loss of the coil and the loss of the magnetic core in the power conversion process, the energy conversion efficiency per unit volume is greatly improved, and the input end of the power conversion device can adapt to input voltages in different ranges without influencing the use of the inductor; the cost is greatly reduced without changing the volume because the number of turns of the coil is not increased or a more expensive magnetic core is used.
The inductance of the invention improves the inductance value by reducing the magnetic loss under the condition of the same number of turns as the prior art, reduces the reactive power according to the relationship between the power factor and the reactive power and the apparent power, reduces the voltage drop of the power grid, and reduces the compensation requirement of the power grid on the reactive power.
The simulation results of MATLAB show that the technology is effective and feasible.
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention to the right. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
Fig. 1 is a schematic structural diagram of a power conversion device according to an embodiment of the present invention;
fig. 2 is a cross-sectional view of a power conversion device provided by an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a framework provided by an embodiment of the invention;
FIG. 4 is a schematic structural diagram of a magnetic core structure according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating the distribution of main magnetic flux and leakage magnetic flux on a magnetic core structure according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a magnetic core structure provided in accordance with another embodiment of the present invention;
FIG. 7 is a schematic structural diagram of a magnetic core structure with an insulator inserted in an air gap according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of the circuit of the present invention.
In the figure: 1-a framework; 11-a winding section; 111-hollow channels; 12-coil pins; 2-a magnetic core; 21-a sub-core; 211-outer ring magnetic core; 212-a newel; 22-a magnetic column; 23-middle magnetic column; 231-sub-middle magnetic column; 3-spacing; 31-a first pitch; 32-a second pitch; 4-a first bump; 41-a first extension; 5-a second bump; 51-a second rim extension; 6-a limiting groove; 7-an air gap; 71-intermediate air gap; 72-side air gap; 8-an insulator; 81-a first plastic sheet; 9-a heat sink; 91-glue layer.
It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.
In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Examples
Referring to fig. 8, the circuit for improving the power quality of the power grid of the present invention includes a rectifying and filtering circuit connected to the input terminal of the power grid, a power factor correction circuit, a high frequency inverter circuit, a control circuit and an output terminal, wherein the high frequency inverter circuit includes a magnetic core and a coil for magnetic coupling, the coil is wound on an insulating structure, and a part of the magnetic core is disposed in a hollow channel of the insulating structure.
In an embodiment of the present invention, the magnetic core and the coil are magnetically coupled to form an inductor, and the circuit for improving the power quality of the power grid is a switching power supply circuit of the power conversion device.
As shown in fig. 5, fig. 5 is a core structure of an embodiment of the present invention, and fig. 5 shows the distribution of main magnetic flux and leakage magnetic flux on the core structure; the magnetic core structure comprises a magnetic core and a coil sleeved on part of the magnetic core, wherein an air gap is formed in the part of the magnetic core, current is conducted in the coil after the coil is electrified, when the current is conducted in the coil, a magnetic field is formed in the space around the coil, the magnetic permeability of the magnetic core is better than that of air, most of magnetic flux forms a loop along the iron core and the air gap, the part of magnetic flux becomes main magnetic flux, and the main magnetic flux forms a circulation loop in the magnetic core to store most of energy and is irrelevant to eddy current loss. The inductor also comprises leakage magnetic flux which comprises diffusion magnetic flux and bypass magnetic flux. The diffused flux is the diffused flux at the edge of the air gap and is caused by the magnetic pressure drop at the upper and lower end surfaces of the air gap, and the part of the flux enters the window of the magnetic core, so that eddy current loss is generated on the winding near the air gap. The bypass magnetic flux is leakage magnetic flux crossing the magnetic core window, and the magnetic force line cuts the winding to generate eddy current loss. In fact, a part of the magnetic flux is not in a self-loop through the air gap, and the part of the magnetic flux is also leakage magnetic flux, and the magnetic flux which does not pass through the magnetic core to form a closed loop is generally called leakage magnetic flux.
In prior art, the coil of inductance carries out the overwhelming majority or cuts completely to the magnetic leakage flux of magnetic core, leads to the coil eddy current loss to appear, has improved the coil loss of inductance to reduce the inductance value, consequently, adopt the coil to carry out the partial cutting to the magnetic leakage flux of magnetic core, also reduce the coil and to the cutting of the magnetic leakage flux of magnetic core with the eddy current loss that reduces the coil promptly, thereby under the unchangeable condition of coil turn, improve power conversion equipment's inductance value.
In the embodiment of the invention, at least part of the coil is arranged with a distance from the magnetic core.
As shown in fig. 2, in the embodiment of the present invention, the insulating structure includes a bobbin 1, on which a winding portion 11 is disposed, a hollow channel 111 is disposed inside the bobbin, the magnetic core has a magnetic core window, an air gap is disposed on a portion of the magnetic core 2, and the magnetic core forms leakage flux at the air gap, by disposing at least a portion of the coil and the magnetic core with a gap 3 therebetween, the coil can be far away from the leakage flux of the magnetic core, and cutting of the leakage flux of the magnetic core by the coil is reduced as much as possible. The eddy current loss is reduced, and the inductance of the power conversion device is improved; the number of turns of the coil is not increased or a more expensive magnetic core is used to reduce the eddy current loss of the coil, so that the cost is reduced; as shown in fig. 1 and 2, the insulation structure includes a frame 1, the frame 1 has a winding portion 11 for winding a coil, a hollow channel 111 is axially disposed on the winding portion 11, a magnetic core 2 is disposed on the frame 1, at least a part of the magnetic core 2 is axially inserted into the hollow channel 111, a space 3 is disposed between the hollow channel 111 and the coil and between the outer wall of at least a part of the magnetic core inserted into the hollow channel 111, due to the existence of the space 3, cutting of the magnetic core by the coil to leakage flux is reduced, especially, the bypass flux cuts the coil in the window of the magnetic core to reduce eddy current loss, the coil disposed outside the window of the magnetic core is far away from the air gap and the bypass flux, cutting of the bypass flux to the coil is reduced, eddy current loss is reduced to the maximum extent, inductance is greatly improved under the condition of the same. The insulation has no effect on the cutting, the insulation has a thickness, the distance 3 according to the invention is to provide a distance between the coil and the core, and increasing the thickness of the insulation will result in a reduction of the distance 3 and even in contact of the inner wall of the insulation with the core, while still maintaining the arrangement with a distance between at least part of the coil and the core.
It should be noted that a distance 3 is provided between at least part of the magnetic core and the hollow channel 111, where the distance 3 is a distance 3 between each part of the magnetic core 2 and the coil passing through the wall of the hollow channel 111, and is set such that part of the coil protrudes out of the core window of the magnetic core 2, and in a preferred embodiment, the wall of the hollow channel 111 protrudes out of the core window of the magnetic core 2, and is set such that a distance 3 is provided between the inner wall of the hollow channel 111 and the core window of the magnetic core 2.
As shown in fig. 2, in the embodiment of the present invention, two magnetic pillars 22 are disposed on two opposite sides of the magnetic core 2, a middle magnetic pillar 23 is disposed on the magnetic core between the two magnetic pillars 22, the middle magnetic pillar 23 is inserted into the hollow channel 111, and a space 3 is disposed between the middle magnetic pillar 23 and the hollow channel 111 or a space 3 is disposed between the middle magnetic pillar 23 and the coil through a wall of the hollow channel 111.
In one embodiment of the invention, the middle part of the magnetic core 2 is provided with the middle magnetic column 23, the middle magnetic column 23 is inserted into the hollow channel 111, the middle magnetic column 23 is provided with the air gap 7, the air gap 7 is arranged in the middle part of the magnetic core 2, the air gap 7 is used for reducing the magnetic conductivity, so that the coil characteristics are less dependent on the initial magnetic conductivity of the magnetic core material, the air gap can avoid the magnetic saturation phenomenon under the alternating current large signal or direct current bias, the inductance can be better controlled, and in addition, the distance 3 is arranged between the whole outer wall of the middle magnetic column 23 and the inner wall of the hollow channel, so that the cutting of the magnetic leakage flux of the air gap 7 to the.
As shown in fig. 2, 3 and 4, in the embodiment of the present invention, the magnetic core 2 includes two sub-magnetic cores 21, and the sub-magnetic cores 21 include an outer ring magnetic core 211 and a center pillar 212 disposed inside the outer ring magnetic core 211; the two outer ring cores 211 are opposite and contact to form two magnetic columns and core windows, and the two middle columns 212 are opposite and inserted into the hollow channel 111 at intervals to form the middle magnetic column 23 and the air gap 7.
In the embodiment of the present invention, the magnetic core 2 includes two sub-magnetic cores 21, and each of the sub-magnetic cores 21 includes an outer ring magnetic core 211 and a center pillar 212 disposed inside the outer ring magnetic core 211; the two outer ring magnetic cores 211 are opposite and in contact with each other to form two magnetic columns, the two middle columns 212 are opposite and spaced to form middle magnetic columns, an air gap in the middle magnetic columns is formed between the axial end faces of the two middle columns 212, and other air gaps are respectively arranged on the two middle columns 212; one side of each of the two sub-magnetic cores 21 is open, so that the outer ring magnetic core 211 has a semi-ring structure, which may be a circular semi-ring or a square semi-ring; a middle pillar 212 is arranged at the inner side of the outer ring magnetic core 211, and the two middle pillars 212 are opposite and form a middle magnetic pillar 23 at intervals; be equipped with the air gap on the middle magnetic column 23, be equipped with the interval between the outer wall of middle magnetic column 23 and hollow passageway 111 for be equipped with the interval between air gap and the space passageway 111, thereby make the magnetic leakage flux on the magnetic core 2 can keep away from the coil.
Specifically, the two sub-magnetic cores have the same size and are both in an E shape, the outer ring magnetic core comprises two sub-magnetic columns arranged on two sides of the central column and a connecting magnetic column for connecting the two sub-magnetic columns, the central column 212 is inserted into the hollow channel 111, one side wall of the winding part is clamped between one sub-magnetic column and the central column and is abutted against the connecting magnetic column, the opposite side wall of the winding part is clamped between the other sub-magnetic column and the central column and is abutted against the connecting magnetic column, the outer ring magnetic core 211 is in a semi-ring structure, the semi-ring structure is a square semi-ring, the outer ring magnetic core 211 comprises sub-magnetic columns arranged on two sides of the central column 212 and a connecting magnetic column for connecting the two sub-magnetic columns, and the two sub-magnetic columns; one sub-magnetic column, the middle column 212 and the connecting magnetic column enclose a clamping space, the other sub-magnetic column, the middle column 212 and the connecting magnetic column enclose another holding space, and the two clamping spaces are used for being matched with the framework 1 of the power conversion device; the two sub-cores 21 are each E-shaped, so that the length of the center leg 212 of the sub-core 21 is smaller than that of the sub-core, thereby forming an air gap between the two center legs 212 when the outer ring cores 211 are opposed and in contact.
As shown in fig. 2, in the embodiment of the present invention, the center pillar 23 is a rectangular parallelepiped pillar, the distances between the upper and lower end surfaces of the center pillar and the hollow passages opposite thereto are equal, and the distances between the left and right end surfaces of the center pillar and the hollow passages are equal. The center pillar 23 may have other shapes. The upper end face and the lower end face of the center pillar are basically in the same plane with the window end face of the magnetic core, and each end face is a horizontal plane; because the hollow channel 111 has different shapes and the middle magnetic column 23 has different insertion ways, a first distance 31 is provided between the upper end surface and the lower end surface of the middle magnetic column 23, that is, between the end surface of the window of the magnetic core and the wall of the hollow channel 111, the wall of the hollow channel 111 includes a first wall and a second wall opposite to each other, and a first distance 31 is provided between the two end surfaces of the window of the magnetic core, respectively, it can be understood that the first distance 31 is substantially the distance between the two end surfaces of the window of the magnetic core and the coil wound on the outer wall of the hollow channel 111. A second distance 32 is arranged between the coil and the third wall and the fourth wall opposite to the left end face and the right end face of the middle magnetic column 23 through the hollow channel 111; the two first pitches 31 may be equal or different, the two second pitches 32 may be equal or different, preferably, the two first pitches 31 are equal, the two second pitches 32 are equal, the first pitch is 1/3-1/6 of the height of the magnetic core, and the second pitch is preferably larger than the diameter of the coil and smaller than the width of the middle pillar. The cutting of the leakage flux of the coil to the magnetic core 2, mainly the bypass flux, is reduced in a large range. The first distance and the second distance substantially ensure the distance between the coil and the magnetic core, and can be the distance formed by the inner wall of the hollow channel 111 and the magnetic core in a relative mode, or the distance formed by increasing the thickness of the hollow channel 111.
In the embodiment of the present invention, as shown in fig. 6 and 7, n air gaps may be further provided on the magnetic core, that is, n air gaps divide the magnetic core into multiple sections, so that the magnetic core intermittently generates leakage magnetic flux, mainly diffused magnetic flux, wherein the sum of the widths of n air gaps is equal to the width of an air gap when the magnetic core has one air gap, so that the width of the air gap when the magnetic core is provided with n air gaps is reduced relative to the width of the air gap when the magnetic core is provided with one air gap, so that the leakage magnetic flux flowing through an air self-loop is reduced, when the leakage magnetic flux is reduced, the magnetic loss of the magnetic core is reduced, and when the leakage magnetic flux is reduced, the leakage magnetic flux cutting of the magnetic core by the coil is reduced, the eddy current loss of the coil is reduced, and in combination with the arrangement of the second distance described above, the distance between the diffused magnetic flux and the, the eddy current loss is greatly reduced, and the arrangement of the air gap 7 can also prevent magnetic saturation.
For the existing magnetic core structure, only one air gap is provided on the magnetic core 2, as shown in fig. 6 and 7, in the magnetic core structure of the present invention, at least two air gaps 7 are provided on the magnetic core 2, and the width of all the air gaps 7 is equal to the width of the air gap when one air gap 7 is provided on the magnetic core 2. For example, if the width of one air gap is 8mm in the prior art, then the sum of the widths of the air gaps is 8mm in the present application.
In the embodiment of the invention, the magnetic core 2 is provided with the plurality of air gaps 7, so that the relative width of the air gaps 7 is reduced, and the purposes of reducing the leakage magnetic flux and further reducing the magnetic loss of the magnetic core structure are achieved; moreover, on the basis of the purpose of improving the inductance, the material of the magnetic core is not changed, so that the production cost is reduced; two magnetic columns 22 are arranged on two opposite sides of the magnetic core, a middle magnetic column 23 is arranged on the magnetic core between the two magnetic columns 22, at least two air gaps are arranged on the two magnetic columns and the middle magnetic column 23, and the width of each air gap is equal to the width of the air gap when one air gap is arranged on the middle magnetic column. The two magnetic columns 22 and the middle magnetic column 23 are rectangular magnetic columns; in other embodiments, the shape of the magnetic cylinder 22 can be changed into a cylinder, a polygonal prism or an irregular cylinder according to actual requirements; specifically, at least two air gaps are arranged on each of the two magnetic columns 22 and the middle magnetic column 23, and the number of the air gaps can be set according to actual requirements; the air gap 7 is generally formed by two magnetic columns 22 which are opposite and arranged at intervals, the space between the two magnetic columns 22 forms the air gap 7, and the width of the air gap 7 generally refers to the dimension of the air gap in the axial direction of the magnetic columns 22.
As shown in fig. 6 and 7, in the embodiment of the present invention, at least two air gaps are disposed on the middle magnetic pillar 23, the at least two air gaps are disposed at intervals along the axial direction of the middle magnetic pillar, and the width dimensions of the air gaps along the axial direction of the middle magnetic pillar 23 are equal or different. As a preferred embodiment, only the middle magnetic pillar 23 is provided with at least two air gaps, for example, the middle magnetic pillar is provided with three air gaps, the three air gaps are arranged at intervals along the axial direction of the magnetic pillar 22, and preferably, the three air gaps are uniformly arranged along the axial direction of the magnetic pillar; the width of each air gap on the middle magnetic pillar 23 is equal, or the width of each air gap on the middle magnetic pillar 23 can be set to be unequal according to actual needs.
In the embodiment of the present invention, the magnetic core includes two sub-magnetic cores 21, each sub-magnetic core 21 includes an outer ring magnetic core 211 and a center pillar 212 disposed inside the outer ring magnetic core 211; the two outer ring magnetic cores 211 are opposite and contact to form two magnetic columns, the two middle columns 212 are opposite and spaced to form the middle magnetic column 23, one air gap in the middle magnetic column 23 is formed between the axial end faces of the two middle columns 212, and other air gaps are respectively arranged on the two middle columns 212.
In the embodiment of the present invention, the magnetic core is composed of two sub-magnetic cores 21, each sub-magnetic core 21 includes an outer ring-shaped magnetic core 211 and a middle pillar 212 disposed inside the outer ring-shaped magnetic core 211, and one side of each of the two sub-magnetic cores 21 is open, so that the outer ring-shaped magnetic core 211 is a semi-ring structure, which may be a circular semi-ring or a square semi-ring; the center pillars 212 are disposed inside the outer ring core 211, the two center pillars 212 are opposite to each other and spaced to form the middle magnetic pillar 23, axial end surfaces of the two center pillars 212 form one air gap of the middle magnetic pillar, and other air gaps of the middle magnetic pillar 23 are opened on the two center pillars 212, for example, three air gaps are opened on the middle magnetic pillar, axial end surfaces of the two center pillars 212 form one air gap of the three air gaps, another air gap of the three air gaps is disposed on one center pillar 212, and another air gap of the three air gaps is disposed on the other center pillar 212.
As shown in fig. 6 and 7, in the embodiment of the present invention, the two sub-magnetic cores 21 have the same size and are both in an E shape, a middle air gap 71 of the middle magnetic column 23 is formed between the axial end surfaces of the two middle columns 212, and an air gap opened in each middle column 212 is a side air gap 72.
In the embodiment of the present invention, the two sub-magnetic cores 21 are both E-shaped, the outer ring magnetic core 211 is a semi-ring structure, the semi-ring structure is a square semi-ring, the outer ring magnetic core 211 includes sub-magnetic columns disposed on both sides of the middle column 212 and a connecting magnetic column connecting the two sub-magnetic columns, and the two sub-magnetic columns and the connecting magnetic column are both perpendicular to the connecting magnetic column; one sub-magnetic column, the middle column 212 and the connecting magnetic column enclose a plugging space, the other sub-magnetic column, the middle column 212 and the connecting magnetic column enclose another plugging space, and the two plugging spaces are used for being matched with a framework of the power conversion device; the two sub-magnetic cores 21 are both in an E shape, so that the length of the middle pillar 212 of the sub-magnetic core 21 is smaller than that of the sub-magnetic pillar, and thus when the outer ring magnetic cores 211 are opposite and in contact, an air gap can be formed between the two middle pillars 212 at intervals; specifically, the width of the middle air gap 71 is greater than or equal to the width of the side air gaps 72, and the spacing between the air gaps is equal; preferably, the width of the middle air gap 71 is larger than the width of the side air gaps 72, so as to avoid the situation that the width of the side air gaps 72 is large and is close to the two sides of the magnetic core 2, thereby causing the damage of the magnetic core 2 to increase.
Several air gaps are set in the window of the magnetic core, and the middle column has large magnetic potential difference to reduce the scattered magnetic flux. Since for pulsating magnetic fields, stray flux couples noise and EMI into the external space, causing interference to external circuits and even to the power grid. In the window of the magnetic core, a second distance 32 is arranged between the coil and the left end face and the right end face of the middle magnetic column 23 through the third wall and the fourth wall which are opposite to each other of the hollow channel 111; the distance between the diffused magnetic flux and the coil is increased, the diffused magnetic flux and the diffused magnetic flux are attenuated along the distance, or the swing amplitude of the magnetic flux is less or the coil in the magnetic core window is difficult to cut, so that the eddy current loss is greatly reduced, and the noise and the EMI are prevented from being coupled to the external space by the diffused magnetic flux, and the interference to an external circuit or even a power grid is avoided.
The inductor, namely the power conversion device, of the invention satisfies the following formula:
Figure 145727DEST_PATH_IMAGE001
wherein r is a radius of the magnetic core, or a half of a radius of a center pillar of the magnetic core, or a width of the center pillar, and is a total width of the air gap, d is a distance between the coil and the magnetic core, K is a reduced value of a magnetic flux of the magnetic core, γ is a reduced value of a fringe magnetic flux loss, M is an effective reduced value of the magnetic flux, and the effective value of the magnetic flux is positively correlated with the magnetic flux; at least n air gaps are formed in the magnetic core, the width of each air gap is 1 and 2 … … n, and the sum of the widths is 1+2+ … … + n =.
It should be noted that, in the embodiment of the present invention, the coil is equivalently sleeved on the middle magnetic column, n air gaps are opened on the middle magnetic column, and d can be regarded as an average distance between the middle magnetic column and the hollow flow channel;
the power supply conversion device designed by adopting the relational expression has lower loss under the condition of adjusting d and the number of turns of the coil, and the inductance L is larger under the condition of the same number of turns N due to the increase of the effective value of the inductance magnetic flux phi. It can also be understood that, under the condition that other parameters of the inductance are not changed, the same inductance L can be obtained under the condition that the number of turns N of the inductance is lower than the normal inductance, and therefore the loss caused by the inductance coil is further reduced.
It is understood that increasing the value of d reduces the coil eddy current loss and increases the effective reduced value M of the magnetic flux. Increasing the value of d may (but is not limited to) be done in different ways, such as thickening the insulating layer 12, changing the skeleton 1, etc.
The data in table 1 are shown in table 1, in which a core having a center leg radius r =5mm, a coil having 50 turns, and a total length of the winding portion 11 of 42mm are used, and the total length is divided into 4 groups for different values and d values, inductance of the corresponding power conversion device is measured, and the eddy current loss of the coil is calculated, and the measurement results are compared with the control groups 1 and 2. The data of examples 1 to 3 are shown in Table 1, and EE4220 and EE425 are used as magnetic cores.
Example 4
This embodiment is substantially the same as embodiment 1 except that:
referring to fig. 3, the number of the air gaps is 5, the width of each air gap is 1, 2, 3, 4, 5, and 1+2+3+4+5=8 mm.
In the present embodiment, 1=2=3=4=1mm, 5=4 mm.
It should be noted that, 2 air gaps are provided on each magnetic core 2 among the 5 air gaps, that is, the portion of the magnetic core 2 extending into the core slot 11 is 3 sections, each section is connected in sequence through an insulating pad, and each section of the magnetic core 2 is separated from each other to form an air gap.
In practical production, a single magnetic core 2 is segmented, and the segmented magnetic core 2 is tightly pressed with an insulating pad to form a magnetic core with an air gap.
Comparative example 1
This comparative example is substantially the same as example 1 except that:
the values of d and d were both randomly selected, and in this comparative example, =8mm, d =2 mm.
Comparative example 2
This comparative example is substantially the same as example 1 except that:
the values of d and d were both randomly selected, and in this comparative example, =8mm, d =1 mm.
TABLE 1
Grouping δ(mm) d(mm) Inductance value (mu H) Eddy current loss (W)
1 8 4 89 1.8
2 5 2.5 85 2.15
3 15 7.5 81 2.85
4 - 4 92 1.5
Control 1 8 2 72 3.5
Control 2 8 1 70 4.5
As can be seen from table 1, group 2 and group 3 all achieve good results, wherein group 1 achieves the best results, and in addition, as can be seen from group 4, when a plurality of air gaps are adopted, the influence of the diffused magnetic flux on the winding is reduced, the inductance can be further improved, and the eddy current loss can be further reduced.
As can be seen from the control 1 group and the control 2 group, when the value of the sum d is randomly selected, the effect achieved is significantly lower than that of the examples of the present application.
Fig. 8 is a schematic diagram of the device and method for improving the power quality of the power grid according to the present invention. The rectification circuit is used for realizing an electrical isolation function, so that the safety of power supply equipment is ensured, and the danger from a high-voltage feeder is avoided. The power factor correction circuit is used for forcing line current to follow line voltage, so that the line current is sinusoidal, the power factor is improved, the harmonic content is reduced, generally, high-voltage direct current of about 300-400V is output, and the frequency and amplitude of the output voltage or current of the inverter are flexibly changed according to the will of people or the requirement of equipment operation by controlling the working frequency and the output time proportion of the inverter circuit. The circuit can also comprise a filter circuit, and the rectifying circuit and the filter circuit can be combined into a circuit.
In the switching power supply, a large number of magnetic material elements such as a high-frequency transformer, a pulse transformer, a commutation and resonance inductor, a power inductor, a filter inductor, a mutual inductor and the like are used, so that a power grid supplies a severely distorted non-sinusoidal current, severe harmonic pollution is caused, the power factor of an input end is reduced, and huge waste and serious damage are caused. Although the circuit of fig. 8 is used for a modern inverter system to suppress harmonic waves, the reliability of the circuit is reduced because the electric energy of the circuit needs to be subjected to three-stage conversion; the efficiency will generally not exceed 80%.
Improving circuit design and control methods to provide high quality electrical power, and increasing conversion rates are the subject of intense research in the power electronics field, but it has been found that circuit improvements generally result in device count and control circuit complexity, in exchange for efficiency improvements also representing high costs; in the prior art, attempts are also made to improve the structure and the manufacturing process of the magnetic material element, so that the problems are solved fundamentally by reducing magnetic flux leakage and leakage inductance and reducing loss.
The inductance magnetic core and the coil in the circuit are arranged into a bypass magnetic flux part cutting winding to reduce the loss of magnetic leakage and leakage inductance; further, the magnetic core and the coil are arranged to be a bypass magnetic flux part to cut the winding in the window of the magnetic core so as to reduce the loss of magnetic leakage and leakage inductance. Furthermore, the center column is further arranged into a plurality of spaced air gaps, so that the interference and the loss of magnetic leakage and leakage inductance are further reduced, the heat dissipation is increased, the problem of loss of inductance is fundamentally solved, and harmonic waves and voltage fluctuation are reduced by adopting the simplest circuit design in a power grid, so that the power factor is improved, and the electric energy quality is improved.
The inductance corresponding to the leakage flux in the general inductive device is the leakage inductance, and when the switch tube is turned off due to the leakage inductance, the leakage inductance energy storage is released, a voltage peak appears on the switch tube, the turn-off loss of the switch tube is increased, and the switch tube is easy to damage. And the leakage inductance is easy to resonate with the distributed capacitance to cause electromagnetic interference. Meanwhile, as the leakage inductance is equivalent in a series connection mode in the circuit, when the voltage is constant, the larger the leakage inductance is, the lower the effective value of the current is, the output power is reduced, the energy conversion efficiency of the high-frequency transformer is reduced, the resonance is multiplied, and the electromagnetic interference to the circuit and the power grid is increased, so that the reduction of the leakage inductance is very important for reducing the power loss, protecting the performance of a switching tube and a switching power supply and reducing the influence on the power grid. The invention has the advantages that through the arrangement of the distance and the air gap, the magnetic leakage flux of the coil is far away from the magnetic core, the interference is avoided, the output is high, the energy conversion efficiency of the high-frequency transformer is high, the resonance is reduced, and the electromagnetic interference on a circuit and a power grid is reduced.
The size of the current harmonic wave is related to the inductance used, the larger the inductance is, the more sufficient the harmonic wave is suppressed, and the inductance is generally increased by thickening the diameter of a coil in the prior art, so that a series of problems such as power source adaptability deterioration, inductance heating, volume increase and cost increase are often caused. Under the condition of not changing the number of turns of the coil, the invention increases the inductance by reducing the eddy current loss without increasing the volume and the cost, and only an inductor is selected according to the minimum inductance, so that the same number of turns of the coil can greatly improve the suppression of the inductance to the harmonic wave, reduce the harmonic wave of a power grid and improve the quality of the electric energy of the power grid.
Under the condition that the number of turns of the coil is not changed, the inductance of the inductor is greatly improved by reducing the loss of the coil and the loss of the magnetic core in the power conversion process, the energy conversion efficiency is improved, and the input end of the power conversion device can adapt to input voltages in different ranges without influencing the use of the inductor; the cost is greatly reduced without changing the volume because the number of turns of the coil is not increased or a more expensive magnetic core is used.
In the prior art, under normal conditions, the input end of the coil of the power conversion device can be connected to a certain rated voltage, a high-end product can be connected to any input voltage between 170 and 380V, different models are selected and adapted for different voltages, the turbine loss of the inductance structure in the circuit is reduced by nearly 40%, the inductance is improved by 20%, and the loss can enable the input end of the coil of the power conversion device to be connected to the input voltage in a wide range, for example, the input voltage can adapt to the voltage between 110 and 600V in a 1000 watt power output state; preferably, the voltage between 200 and 500V is input, and the model does not need to be replaced. The inductor can resist voltage fluctuation, improves adaptability to power transmission lines with unstable voltage, and avoids power grid fluctuation caused by incapability of starting or normal output due to too low voltage and burnout due to too high voltage.
The frequency, voltage and power supply reliability of the power grid are important indexes for measuring the damage of reactive power to the power grid, and the important indexes comprise: the output of the active power of the generator is reduced, the power supply capacity of power transmission and transformation equipment is reduced, the voltage loss of a line is increased, the electric energy loss is increased, low-power factor operation and voltage reduction are caused, and the capacity of the electrical equipment cannot be fully exerted. The inductance of the invention is improved by reducing the magnetic loss under the condition of the same number of turns as the prior art, the reactive power is reduced according to the relationship between the power factor and the reactive power and the apparent power, the voltage drop of the power grid is reduced, and the requirement of the power grid on the compensation of the reactive power is reduced.
The inductor of the present invention may be the EE, EI, EF, EEL, PEEPEPEEL, ER, ETD, EQ/EQI, EP, EFD, EPC, POT, PQ, RM, etc. specifications of the prior art.
As shown in fig. 7, in the embodiment of the present invention, at least two air gaps separate the middle magnetic pillar into a plurality of sub-middle magnetic pillars 231, an air gap is formed between axial end surfaces of two adjacent sub-middle magnetic pillars 231, an insulating member 8 is disposed in each air gap, and the insulating members 8 are respectively attached to the axial end surfaces of the two sub-middle magnetic pillars 231.
In the embodiment of the present invention, the insulating member 8 is inserted into the air gap to connect the two adjacent sub-middle magnetic poles 231, and the insulating member 8 has an insulating property and does not have a cutting effect on the main magnetic flux; the arrangement of a plurality of air gaps and a plurality of insulating pieces 8 ensures that the saturation value of the magnetic core can be improved to be higher and the distribution of the magnetic circuit is more balanced; wherein, the insulating part 8 can be completely inserted into the air gap or partially inserted into the air gap; in addition, the insulating member 8 may be made of various materials and shapes as long as it has no cutting effect on the magnetic lines.
As shown in fig. 7, in the embodiment of the present invention, the insulating member 8 is a first plastic piece 81, the first plastic piece 81 is inserted into the corresponding air gap, two opposite sides of the first plastic piece 81 are respectively attached to the axial end surfaces of the two sub-middle magnetic pillars 231, and the area of the side surface of the first plastic piece 81 is smaller than or equal to the area of the axial end surface of the sub-middle magnetic pillar 231.
In the embodiment of the present invention, the insulating member 8 is made of plastic and is shaped like a sheet, the first plastic piece 81 is inserted into the air gap, one side surface of the first plastic piece 81 is attached to the axial end surface of one sub-middle magnetic pillar 231, and the opposite side surface is attached to the axial end surface of the adjacent sub-middle magnetic pillar 231, so as to connect the two adjacent sub-middle magnetic pillars 231; when the insulator 8 is fully inserted into the air gap, the area of the side surface of the first plastic piece 81 may be smaller than the area of the axial end surface of the sub-intermediate magnetic post 231, or may be equal to the area of the axial end surface of the intermediate magnetic post, as long as it is ensured that two adjacent sub-intermediate magnetic posts 231 can be connected, preferably, the area of the side surface of the first plastic piece 81 is equal to the area of the axial end surface of the intermediate magnetic post, so as to increase the connection strength between two adjacent sub-intermediate magnetic posts 231.
Further, be equipped with the second plastic piece that extends along the axial direction of middle magnetic cylinder on the middle magnetic cylinder, the setting of magnetic cylinder in the middle of the laminating of second plastic piece, each first plastic piece is connected with the second plastic piece is perpendicular, the same one side of second plastic piece is located to all first plastic pieces, the second plastic piece integrates a plurality of each first plastic piece 81, avoid a plurality of first plastic pieces 81 the condition of easily losing to appear, and can realize inserting a plurality of first plastic pieces 81 in the air gap that corresponds separately simultaneously, improve insertion efficiency.
As shown in fig. 7, in the embodiment of the present invention, the heat dissipation member 9 is disposed on two opposite sides of the first plastic piece 81, one side of the heat dissipation member 9 is connected to the axial end surface of the middle magnetic pillar 231, and the other side is connected to one side of the first plastic piece 81.
In the embodiment of the present invention, the arrangement of the heat dissipation body 9 enables the first plastic sheet 81 to be connected to the sub-middle magnetic pillars 231, so as to implement the connection between two adjacent sub-middle magnetic pillars 231, and meanwhile, the heat dissipation body 9 can reduce the temperature of the magnetic core, thereby facilitating the heat dissipation and further improving the saturation value.
As shown in fig. 7, in the embodiment of the present invention, the heat radiator 9 is a glue layer 91 formed by adhering the first plastic sheet 81 to the axial end surfaces of the two sub-intermediate magnetic pillars 231.
In the embodiment of the present invention, the glue layer 91 is epoxy glue, and may be other types of materials capable of performing an adhesion function, and meanwhile, the material cannot have a magnetic permeability function and needs to have a heat dissipation function; the area of the side surface of glue layer 91 may be smaller than the area of the side surface of plastic sheet 81 and the area of the axial end surface of sub-middle magnetic post 231, or may be equal to the area of the side surface of plastic sheet 81 and the area of the axial end surface of sub-middle magnetic post 231, preferably, the area of the side surface of glue layer 91 is equal to the area of the side surface of plastic sheet 81 and the area of the axial end surface of sub-middle magnetic post 231, so as to improve the connection strength between two adjacent sub-middle magnetic posts 231.
As shown in fig. 3, in the embodiment of the present invention, the first protrusion 4 axially protruding relative to the winding portion 11 is disposed on each of two opposite sides of the top of the winding portion 11, the second protrusion 5 axially protruding relative to the winding portion 11 is disposed on each of two opposite sides of the bottom of the winding portion 11, and a portion of the connection magnetic core is sandwiched between the first protrusion 4 and the second protrusion 5.
In the embodiment of the invention, when the upper end surface, the lower end surface, the left end surface and the right end surface of the center pillar are provided with intervals with the inner wall of the hollow channel 111, in order to realize that the magnetic core 2 is arranged on the framework 1, therefore, the first lug 4 which protrudes along the axial direction is arranged on the two opposite sides of the top of the winding part 11, the second lug 5 which protrudes along the axial direction is arranged on the two opposite sides of the bottom of the winding part 11, a clamping space is formed between the first lug 4 and the second lug 5, part of the connecting magnetic core is clamped in the clamping space, the assembly of the magnetic core 2 and the framework 1 is realized, and the stability of the magnetic core 2 on.
As shown in fig. 3, in the embodiment of the present invention, both left and right sides of the first protrusion 4 radially protrude with respect to the winding portion 11 to form two first extending portions 41, both left and right sides of the second protrusion radially protrude with respect to the winding portion 11 to form two second extending portions 51, and the sub-magnetic pole and the remaining portion of the connecting magnetic core are sandwiched between the first extending portions 41 and the second extending portions 51.
In the embodiment of the present invention, in order to further enhance the assembling strength between the magnetic core 2 and the frame 1, the first extended portion 41 is disposed on both left and right sides of the first protrusion 4, the second extended portion 51 is disposed on both left and right sides of the second protrusion 5, a clamping space is formed between the first extended portion 41 and the second extended portion 51, and the sub-magnetic pole and the remaining portion of the connecting magnetic core are disposed in the clamping space.
As shown in fig. 3, in the embodiment of the present invention, two first protrusions radially protrude relative to the winding portion 11 to form a first groove, two second protrusions radially protrude relative to the winding portion 11 to form a second groove, the winding portion 11 located between the first protrusions and the second protrusions is provided with four third protrusions radially protruding relative to the winding portion 11, a third groove is formed between two opposite third protrusions, and the grooves are sequentially connected to form a continuous limiting groove 6.
In the embodiment of the invention, the first protrusion protrudes upwards and radially relative to the winding part 11, so that a first groove body is formed between two opposite first protrusions, the second protrusion protrudes downwards and radially relative to the winding part 11, so that a second groove body is formed between two opposite second protrusions, four third protrusions protruding radially relative to the winding part 11 are further arranged on the winding part 11 between the first protrusion and the second protrusion, a third groove body is formed between two opposite third protrusions, and a limiting groove 6 for limiting the coil is formed among the first groove body, the second groove body, the third groove body and the fourth groove body, so that the coil is wound in the limiting groove 6, and the phenomenon that the coil is wound disorderly during winding is avoided.
As shown in fig. 3, in the embodiment of the present invention, the second protrusion is provided with a plurality of coil pins 12 arranged at intervals along the left-right direction.
In the embodiment of the present invention, the second protrusion is provided with a coil pin 12, the coil wound on the winding portion 11 has an input end and an output end, and the input end and the output end of the coil are both provided on the coil pin 12.
The invention also provides a power supply conversion method, and under the condition that the number of turns of the coil is not changed, the power supply conversion device provided by the technical scheme widens the range of input voltage accessed by the input end of the coil by increasing the distance between at least part of the coil and the magnetic core or reducing the width of an air gap on the magnetic core.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A circuit for improving the electric energy quality of a power grid is characterized by comprising a power grid input terminal, a rectifying circuit, a power factor correction circuit, a high-frequency inverter circuit and an output terminal which are sequentially connected, wherein a control circuit is in control connection with the rectifying circuit, the power factor correction circuit and the high-frequency inverter circuit, the high-frequency inverter circuit comprises a magnetic core and a coil which are used for magnetic coupling, the coil is wound on an insulating structure, and one part of the magnetic core is arranged in a hollow channel of the insulating structure; the core and coil arrangement is such that a portion of the flux cuts the coil and a portion of the bypass flux cuts the coil within the core window to reduce eddy current losses.
2. A circuit for improving power quality of a power grid as claimed in claim 1, wherein the leakage flux cuts the coil within the core window to reduce eddy current losses.
3. A circuit for improving power quality of a power grid as claimed in claim 2, wherein at least some of the windings are spaced from the window end of the core by a first distance.
4. A circuit for improving power quality of a power grid according to claim 3, wherein the partial coil is spaced from the window end of the core by a first distance through the wall of the hollow channel of the insulating structure.
5. A circuit for improving the power quality of a power grid according to claim 4, wherein the coil is spaced from the two end faces of the core window by a first distance through the first and second opposite walls of the hollow passage of the insulating structure.
6. A circuit for improving the power quality of a power grid according to any one of claims 1 to 5, wherein the coil is provided with a second distance between the left end face and the right end face of the middle magnetic column respectively corresponding to the third wall and the fourth wall which are opposite to each other and pass through the hollow channel of the insulating structure.
7. A circuit for improving the power quality of a power grid according to any one of claims 1 to 5, wherein the first and second opposite walls of the hollow channel of the insulating structure are spaced from the two end faces of the window of the magnetic core by a first distance, and the first distance is 1/3-1/6 of the height of the magnetic core.
8. A circuit for improving the power quality of a power grid according to any one of claims 1-5, wherein the air gaps in the magnetic core are n spaced air gaps, n is greater than or equal to 2, and the sum of the widths of the n air gaps is equal to the width of the air gap when the magnetic core has one air gap, so as to reduce the eddy current loss.
9. A circuit for improving power quality of a power grid according to claim 8, wherein said magnetic core and said coil for magnetic coupling satisfy the following equation:
Figure 177349DEST_PATH_IMAGE001
where r is a radius of the core or a radius of a center pillar of the core, and is a width of the air gap, d is a distance between the coil and the core, K is a reduced value of a magnetic flux of the core, γ is a reduced value of a fringe magnetic flux loss, and M is an effective reduced value of the magnetic flux.
10. A method of improving the power quality of a power grid using the circuit of any one of claims 1 to 9, comprising: the high-frequency inverter circuit is characterized in that a magnetic core and a coil in the high-frequency inverter circuit are arranged as a part of a bypass magnetic flux cutting winding to reduce eddy current loss.
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* Cited by examiner, † Cited by third party
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CN113223824A (en) * 2021-04-29 2021-08-06 东莞沛波电子有限公司 High-capacity power inductor convenient for automatic production
CN113436857A (en) * 2021-06-18 2021-09-24 青岛海信日立空调系统有限公司 Transformer, circuit substrate and switching power supply
CN113436850A (en) * 2021-06-30 2021-09-24 天津大学 High-frequency segmented air gap planar transformer

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Denomination of invention: A circuit and method for improving power quality

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