WO2022217494A1 - 平面变压器及相关设备 - Google Patents

平面变压器及相关设备 Download PDF

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Publication number
WO2022217494A1
WO2022217494A1 PCT/CN2021/087201 CN2021087201W WO2022217494A1 WO 2022217494 A1 WO2022217494 A1 WO 2022217494A1 CN 2021087201 W CN2021087201 W CN 2021087201W WO 2022217494 A1 WO2022217494 A1 WO 2022217494A1
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WO
WIPO (PCT)
Prior art keywords
magnetic core
cover
auxiliary
magnetic
core cover
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Application number
PCT/CN2021/087201
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English (en)
French (fr)
Inventor
余鹏
邹军
Original Assignee
华为数字能源技术有限公司
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Filing date
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Application filed by 华为数字能源技术有限公司 filed Critical 华为数字能源技术有限公司
Priority to EP21936386.8A priority Critical patent/EP4310871A4/en
Priority to CN202180096444.8A priority patent/CN117063254A/zh
Priority to PCT/CN2021/087201 priority patent/WO2022217494A1/zh
Publication of WO2022217494A1 publication Critical patent/WO2022217494A1/zh
Priority to US18/486,469 priority patent/US20240038437A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/38—Auxiliary core members; Auxiliary coils or windings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2804—Printed windings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/26—Fastening parts of the core together; Fastening or mounting the core on casing or support
    • H01F27/263—Fastening parts of the core together
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/30—Fastening or clamping coils, windings, or parts thereof together; Fastening or mounting coils or windings on core, casing, or other support
    • H01F27/306—Fastening or mounting coils or windings on core, casing or other support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F3/00—Cores, Yokes, or armatures
    • H01F3/10—Composite arrangements of magnetic circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F30/00—Fixed transformers not covered by group H01F19/00
    • H01F30/06—Fixed transformers not covered by group H01F19/00 characterised by the structure
    • H01F30/10—Single-phase transformers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2804—Printed windings
    • H01F2027/2819—Planar transformers with printed windings, e.g. surrounded by two cores and to be mounted on printed circuit

Definitions

  • the invention relates to the technical field of power electronics, in particular to a planar transformer and related equipment.
  • a planar transformer is a transformer with high frequency, low profile, small height and high operating frequency. Transformer is a key component in the power supply. Traditional transformers are usually composed of ferrite cores and copper coils, which are bulky and prone to electromagnetic interference. Planar transformers can effectively solve the problems of volume and high frequency, and can be widely used in various electronic equipment in the field.
  • the present application discloses a planar transformer and related equipment.
  • the planar transformer has a thinner thickness and can better meet the design of ultra-thin products.
  • the present application provides a planar transformer, comprising: a magnetic core, the magnetic core comprising a first magnetic core cover, a second magnetic core cover, n first magnetic core legs and k second magnetic core legs, the n first magnetic core legs and k second magnetic core legs are disposed between the first magnetic core cover and the second magnetic core cover, and both n and k are integers greater than 0;
  • a primary winding and a secondary winding coupled to each other are arranged on each of the n first magnetic core columns, and an auxiliary winding is arranged on each of the k second magnetic core columns inductor winding;
  • the first magnetic flux When energized, the first magnetic flux cancels part of the second magnetic flux when passing through the first magnetic core cover and the second magnetic core cover, and the first magnetic flux is the auxiliary inductance windings provided on the k second magnetic core legs
  • the generated magnetic flux, the second magnetic flux is the magnetic flux generated by the primary windings arranged on the n first magnetic core legs.
  • the magnetic flux is generated by adding auxiliary inductance windings, so that the magnetic flux can partially offset the magnetic flux of the primary winding of the transformer on the magnetic core cover, thereby reducing the magnetic flux passing through the magnetic core cover, so that a thinner thickness can be designed.
  • Magnetic core cover to better meet the design of ultra-thin products.
  • the planar transformer with small current output can be, for example, a planar transformer composed of only one or two pairs of transformer windings (a pair of transformer windings includes a transformer primary winding and a transformer secondary winding).
  • the structure of the first magnetic core cover and the structure of the second magnetic core cover are symmetrical, the first magnetic core cover includes a first main magnetic core cover and a first auxiliary magnetic core cover, the first magnetic core cover
  • the two magnetic core covers include a second main magnetic core cover and a second auxiliary magnetic core cover; in a plan view obtained by looking down on the planar transformer from the first magnetic core cover to the second magnetic core cover, the first auxiliary magnetic core
  • the area of the cover is smaller than the area of the first main magnetic core cover;
  • first magnetic core legs and the k second magnetic core legs are disposed between the first magnetic core cover and the second magnetic core cover, including:
  • first magnetic core columns are arranged between the first main magnetic core cover and the second main magnetic core cover, and are vertically connected with the first main magnetic core cover and the second main magnetic core cover; the k A second magnetic core column is disposed between the first auxiliary magnetic core cover and the second auxiliary magnetic core cover, and is vertically connected with the first auxiliary magnetic core cover and the second auxiliary magnetic core cover.
  • designing the area of the auxiliary magnetic core cover to be smaller than that of the main magnetic core cover can reduce the occupied area of the overall magnetic core.
  • the area of the magnetic core cover, but the increase is less, that is, the application can design a magnetic core cover with a thinner thickness with less cost of the area occupied by the magnetic core, so as to better meet the design of ultra-thin products .
  • the cross-sectional area of the second magnetic core leg is smaller than the cross-sectional area of the first magnetic core leg.
  • reducing the cross-sectional area of the second magnetic core leg can correspondingly reduce the occupied area of the magnetic core cover, thereby reducing the occupied area of the entire magnetic core.
  • the ratio of the cross-sectional area of the first magnetic core leg and the second magnetic core leg is equal to the number of turns of the auxiliary inductance winding on the second magnetic core leg and the original value on the first magnetic core leg.
  • the ratio of turns of the side windings is equal to the number of turns of the auxiliary inductance winding on the second magnetic core leg and the original value on the first magnetic core leg.
  • the turns ratio between the auxiliary inductance winding and the transformer primary winding is equal to the transformer primary winding
  • the ratio of the cross-sectional area between the auxiliary inductor winding and the auxiliary inductor winding that is, the turns ratio between the auxiliary inductor winding and the primary winding of the transformer is equal to the ratio of the cross-sectional area of the first magnetic core leg and the second magnetic core leg. That is, the design of the present application can make the magnetic flux transmit uniformly, so as to better make the secondary winding generate magnetic induction and reduce the loss of the magnetic core.
  • the ratio of the cross-sectional areas of the first magnetic core leg and the second magnetic core leg can also be controlled by controlling the turns ratio between the auxiliary inductor winding and the primary winding of the transformer.
  • the number of turns of the auxiliary inductor winding is greater than the number of turns of the primary winding.
  • the design of the present application can reduce the loss of the auxiliary inductance winding.
  • the auxiliary inductor winding is electrically connected to the primary winding.
  • the n primary windings in the n first magnetic core legs are connected in series;
  • the k primary windings in the n primary windings and the k auxiliary inductor windings in the k second magnetic core legs are respectively connected in parallel;
  • each of the n primary windings is connected in parallel with at least one of the k auxiliary inductor windings;
  • the k auxiliary inductance windings in the k second magnetic core legs are connected in series and then connected in parallel with the n primary windings connected in series;
  • the auxiliary inductor winding and the primary winding are decoupled or weakly coupled.
  • the design of the present application can reduce the mutual inductance effect between the auxiliary inductor winding and the transformer primary winding.
  • the n first magnetic core columns and the k second magnetic core columns are arranged in the form of an array, and are viewed from the direction from the first magnetic core cover to the second magnetic core cover.
  • the winding directions of the windings on the two horizontally adjacent and vertically adjacent magnetic core legs are opposite.
  • the n first magnetic core legs are arranged in a predetermined area, and the k second magnetic core legs are distributed outside the predetermined area.
  • the present application provides a circuit board, the circuit board comprising the planar transformer according to any one of the above-mentioned first aspect and possible embodiments thereof.
  • the present application provides an electronic device, the electronic device comprising the planar transformer according to any one of the above-mentioned first aspect and possible embodiments thereof.
  • Fig. 1 shows the scene schematic diagram of the planar transformer provided by the present application
  • Figure 2 shows a schematic diagram of the circuit schematic diagram of a planar transformer
  • Figure 3 shows the equivalent schematic diagram of the inductor
  • FIG. 4 shows a schematic diagram of the magnetic core structure provided by the present application
  • FIG. 4A shows a schematic top view of the magnetic core structure provided by the present application
  • FIG. 5 is a schematic diagram showing the transmission direction of the magnetic flux in the magnetic core in the planar transformer provided by the present application.
  • 6 and 7 are schematic diagrams showing the direction of magnetic flux transmission when the planar transformer provided by the present application is viewed from above;
  • Figure 8 shows another schematic diagram of the circuit diagram of the planar transformer
  • FIG. 9 is a schematic diagram of another magnetic core structure provided by the present application.
  • FIG. 9A shows a schematic top view of another magnetic core structure provided by the present application.
  • FIG. 10 is a schematic diagram showing the transmission direction of the magnetic flux in the magnetic core in another planar transformer provided by the present application.
  • 11 and 12 are schematic diagrams showing the direction of magnetic flux transmission when another planar transformer is viewed from the top of the present application;
  • Fig. 13 is another schematic diagram of the circuit schematic diagram of the planar transformer
  • FIG. 14 and FIG. 15 are schematic diagrams showing the direction of magnetic flux transmission in another planar transformer provided in the present application when viewed from the top.
  • planar transformer can be applied to aerospace power supplies, shipboard power supplies, radar power supplies, communication power supplies, electric locomotive or automobile power supplies, computer or integrated chip power supplies, high Frequency heating or lighting power supplies, frequency converters, inverters and various AC/DC (alternating current/direct current, AC/DC) converters, DC/DC converters and other devices.
  • FIG. 1 exemplarily shows a schematic diagram of a circuit system 100 in which the planar transformer is applied in the above-mentioned device.
  • the circuit system 100 includes an input circuit 101 , a planar transformer 102 and an output circuit 103 .
  • the input circuit 101 may be connected to a power source, and the power source may be a DC power source or an AC power source.
  • the DC power source can be, for example, an energy storage battery (such as a nickel-cadmium battery, a nickel-hydrogen battery, a lithium-ion battery, a lithium-polymer battery, etc.) or a solar battery, and the like.
  • the AC power source may be a 220V or 380V grid power source or the like.
  • the planar transformer 102 is used to transform the voltage obtained from the input circuit 101 (eg boost or step down), and then the output circuit 103 outputs the transformed voltage of the planar transformer 102 to the corresponding load to supply power to the load.
  • the load may be, for example, a communication device (eg, a mobile phone), a computer (eg, a computer), an electric vehicle, or the like.
  • planar transformer provided by the present application is not limited to be applied to the above voltage conversion scenarios.
  • FIG. 2 exemplarily shows a circuit schematic diagram when the planar transformer includes only one pair of transformer windings.
  • a pair of transformer windings includes a primary winding and a secondary winding of the transformer.
  • Fig. 2(a) shows the circuit schematic diagram of the conventional planar transformer, wherein Lm is the excitation inductance generated when the excitation current Im flows through the primary winding of the transformer T.
  • Lm is the excitation inductance generated when the excitation current Im flows through the primary winding of the transformer T.
  • the magnetizing inductance L m is exemplarily represented in the schematic diagram of the transformer circuit in the present application.
  • Fig. 2(b) shows the circuit schematic diagram of the planar transformer provided by the present application, wherein L m' is the excitation inductance generated after the excitation current I m' is input to the primary winding of the transformer T, and L ⁇ is the current I ⁇
  • the inductance generated when flowing through the auxiliary inductance winding can be called the auxiliary inductance L ⁇ .
  • the auxiliary inductor winding is connected in parallel with the primary winding of the transformer T.
  • the parallel excitation inductance L m' and the auxiliary inductance L ⁇ in the planar transformer shown in (b) of FIG. 2 are equivalent to the excitation inductance of the planar transformer shown in (a) of FIG. 2 .
  • L m there is generally a mutual inductance between the excitation inductance L m' and the auxiliary inductance L ⁇ .
  • M is the mutual inductance coefficient between the excitation inductance L m' and the auxiliary inductance L ⁇ .
  • the relationship shown in Fig. 3 can be expressed by the following formula:
  • a decoupling relationship or a weak coupling relationship may be designed between the excitation inductance L m' and the auxiliary inductance L ⁇ .
  • the flux linkage ⁇ ⁇ generated by the auxiliary inductance winding when the current I ⁇ flows through the auxiliary inductance winding is the same as that generated in the primary winding of the transformer T when the current I m′ flows through the primary winding.
  • the flux linkage ⁇ m' is equal, namely
  • ⁇ m' ⁇ m' /N m'
  • ⁇ ⁇ is the magnetic flux of the auxiliary inductance winding when the current I ⁇ flows through the auxiliary inductance winding
  • ⁇ m' is the magnetic flux of the primary winding when the current I m' flows through the primary winding of the transformer T
  • N ⁇ is the auxiliary inductance winding
  • the number of turns of N m' is the number of turns of the primary winding of the transformer T.
  • the magnetic flux ratio of the auxiliary inductance winding and the primary winding of the transformer T can be controlled by controlling the turns ratio of the windings.
  • the magnetic flux density B is the ratio of the magnetic flux ⁇ to the area Ae that the magnetic flux ⁇ passes vertically through
  • B ⁇ is the magnetic flux density when the magnetic flux ⁇ ⁇ of the auxiliary inductor winding passes through the area Ae ⁇ perpendicularly when the current I ⁇ flows through the auxiliary inductor winding
  • B m' is the current I m' flowing through the primary winding of the transformer T.
  • FIG. 4 exemplarily shows the structure of a magnetic core 400 of a planar transformer provided by an embodiment of the present application.
  • the magnetic core 400 includes a first magnetic core cover 401 , a second magnetic core cover 402 , a first magnetic core leg 403 and a second magnetic core leg 404 .
  • the structure of the first magnetic core cover 401 and the structure of the second magnetic core cover 402 are symmetrical, the first magnetic core cover 401 includes a first main magnetic core cover 4011 and a first auxiliary magnetic core cover 4012, and the second magnetic core cover 402 The second main magnetic core cover 4021 and the second auxiliary magnetic core cover 4022 are included. It should be noted that the first main magnetic core cover 4011 and the first auxiliary magnetic core cover 4012 are integrally formed in the actual object. In FIG.
  • first magnetic core cover 401 and the second magnetic core cover 402 parallel to the magnetic core leg may also be referred to as a side leg of the magnetic core.
  • first magnetic core leg 403 is disposed between the first main magnetic core cover 4011 and the second main magnetic core cover 4021, and is perpendicular to the first main magnetic core cover 4011 and the second main magnetic core cover 4011 Core cover 4021.
  • the second magnetic core column 404 is disposed between the first auxiliary magnetic core cover 4012 and the second auxiliary magnetic core cover 4022 and is perpendicular to the first auxiliary magnetic core cover 4012 and the second auxiliary magnetic core cover 4022 .
  • FIG. 4 the top view from the first magnetic core cover 401 to the second magnetic core cover 402 can be seen in FIG. 4A .
  • the area of the first auxiliary magnetic core cover 4012 is smaller than that of the first main magnetic core cover 4012 .
  • the area of the first auxiliary magnetic core cover 4012 may also be equal to the area of the first main magnetic core cover 4011. area.
  • first magnetic core cover 401 and the second magnetic core cover 402 can be separated, and the first magnetic core column 403 and the second magnetic core column 404 can also be combined with the first magnetic core cover 401 and the second magnetic core
  • the disassembly of the cover 402 is divided into two parts.
  • the primary winding and the secondary winding of the transformer are arranged on the first magnetic core leg 403 in the above-mentioned magnetic core 400 , and an auxiliary inductance winding is arranged on the second magnetic core leg 404 in the magnetic core 400 , and the auxiliary inductance winding
  • the auxiliary inductance winding is connected in parallel with the primary winding, and the winding direction of the auxiliary inductance winding is opposite to that of the primary winding, thus obtaining a planar transformer provided by the present application.
  • the winding direction of the auxiliary inductance winding and the winding of the primary winding can be, for example, the winding direction of the auxiliary inductance winding is clockwise when viewed from the direction of the first magnetic core cover 401 to the second magnetic core cover 402 , At the same time, the winding direction of the primary winding is counterclockwise when viewed from the first magnetic core cover 401 to the second magnetic core cover 402; The winding direction of the primary winding is clockwise.
  • the planar transformer After the planar transformer is powered on, since the auxiliary inductance winding and the primary winding are connected in parallel and the winding directions of the windings are opposite, the directions of the magnetic fluxes generated by the auxiliary inductance winding and the primary winding are opposite, and the two When the magnetic flux generated by the winding is transmitted to the magnetic core cover through the respective magnetic core legs, it can be partially canceled due to the opposite direction, reducing the magnetic flux passing through the magnetic core cover. Since the magnetic flux density B is the ratio of the magnetic flux ⁇ to the area Ae through which the magnetic flux ⁇ passes perpendicularly, when the magnetic flux in the magnetic core cover decreases, the thickness of the magnetic core cover can be appropriately reduced, that is, the thickness of the magnetic core cover can be reduced. The cross-sectional area through which the magnetic flux passes, which not only reduces the overall thickness of the planar transformer, but also does not cause the problem of magnetic saturation caused by the increase in the magnetic flux density of the magnetic core cover.
  • Figure 5 shows a schematic diagram of the flow of the magnetic flux generated by the auxiliary inductance winding and the primary winding of the transformer after the above-mentioned planar transformer is powered on.
  • the auxiliary inductance winding is not drawn in Figure 5. and the windings of the transformer, but in fact, the primary winding and the secondary winding of the transformer are arranged in the first magnetic core leg 403 , and the auxiliary inductance winding is arranged on the second magnetic core column 404 . It can be seen that the magnetic flux generated by the primary winding forms two magnetic flux loops through the first magnetic core cover 401 and the second magnetic core cover 402 .
  • the magnetic flux generated by the auxiliary inductance winding passes through the first magnetic core cover 401 and the second magnetic core cover 402 also form two magnetic flux loops.
  • the magnetic flux directions of the primary winding and the auxiliary inductance winding in the magnetic core cover are always opposite, so the magnetic flux of the auxiliary inductance winding in the magnetic core cover can partially cancel the magnetic flux of the primary winding.
  • FIG. 6 is a top view from the first magnetic core cover 401 to the second magnetic core cover 402 , the black dots in the figure indicate the flow of magnetic flux out of the page, the cross symbol indicates the flow of magnetic flux into the page, and the arrow indicates the direction of the flow of magnetic flux , that is, the direction of the magnetic flux of the first magnetic core leg 403 is opposite to the direction of the magnetic flux of the second magnetic core leg 404 , and the dotted line frame is the area where the magnetic flux is canceled.
  • a second magnetic core leg 404 may be added.
  • the added second magnetic core leg 404 is also provided.
  • the newly added second magnetic core leg 404 is symmetrical with the second magnetic core 404 shown in FIG. 4 with respect to the first magnetic core leg 403 .
  • FIG. 7 is a plan view from the first magnetic core cover 401 to the second magnetic core cover 402. It can be seen that two second magnetic core columns 404 are symmetrically arranged on both sides of the first magnetic core column 403, and the two The direction of the magnetic flux of each of the second magnetic core legs 404 is opposite to the direction of the magnetic flux of the first magnetic core leg 403 , so that part of the magnetic flux passing through the magnetic core cover can be eliminated.
  • the planar transformer shown in FIG. 7 is compared with the transformer shown in FIG. 6 , and the total number of turns of the auxiliary inductor windings set in the two second magnetic core legs 404 in FIG.
  • the number of turns of the auxiliary inductor windings arranged on the magnetic core leg 404 is equal.
  • the number of turns of the auxiliary inductance winding set on a second magnetic core leg 404 in FIG. 6 is N1
  • the number of turns of the auxiliary inductance winding set on a second magnetic core leg 404 in FIG. 7 is N1/2
  • the other The number of turns of the auxiliary inductor winding arranged in one of the second magnetic core legs 404 is also N1/2.
  • the number of turns of the auxiliary inductance winding can be determined according to the required magnetic flux, and the application does not limit the specific number of turns of the auxiliary inductance winding.
  • planar transformer includes only one pair of transformer windings, and the following describes the case when the planar transformer includes two pairs of transformer windings.
  • FIG. 8 exemplarily shows a circuit schematic diagram of the planar transformer provided by the present application when it includes two pairs of transformer windings.
  • (a) and (b) in Figure 8 show two possible ways of connecting the excitation inductance and the auxiliary inductance.
  • L ⁇ is connected in parallel, and the excitation inductance Lm' of the transformer T1 is connected in parallel with the auxiliary inductance L ⁇ , and then connected in series with the excitation inductance Lm' and the auxiliary inductance L ⁇ of the transformer T2 connected in parallel.
  • one or more auxiliary inductance windings are connected in parallel with the primary winding of the transformer T1
  • another one or more auxiliary inductance windings are connected in parallel with the primary winding of the transformer T2, and then the parallel connection is made.
  • the pairs of windings are connected in series.
  • two auxiliary inductances L ⁇ are connected in series and then connected in parallel with the excitation inductances Lm' of the transformer T1 and the transformer T2 connected in series.
  • at least two auxiliary inductance windings are connected in series, the primary windings of the two transformers are connected in series, and then the auxiliary inductance windings connected in series are connected in parallel with the primary windings connected in series.
  • connection method shown in FIG. 8( a ) or the connection method shown in FIG. 8( b ) in a possible implementation manner, when the power is turned on, the magnetic flux generated in each primary winding is The directions are opposite to the directions of the magnetic fluxes generated by the corresponding auxiliary inductance windings, thereby achieving partial cancellation of the magnetic fluxes.
  • FIG. 9 exemplarily shows the structure of a magnetic core 900 of a planar transformer provided by an embodiment of the present application.
  • the magnetic core 900 includes a first magnetic core cover 901, a second magnetic core cover 902, and two first magnetic core legs (903-1 and 903-2, which may be collectively referred to as the first magnetic core leg 903-1 and the first magnetic core column 903-1 and the first magnetic core column 903-1).
  • the core column 903-2 is the first magnetic core column 903) and the two second magnetic core columns (904-1 and 904-2, which may be collectively referred to as the second magnetic core column 904-1 and the second magnetic core column 904-2 below).
  • the structure of the first magnetic core cover 901 and the structure of the second magnetic core cover 902 are symmetrical, the first magnetic core cover 901 includes a first main magnetic core cover 9011 and a first auxiliary magnetic core cover 9012, and the second magnetic core cover 902 A second main magnetic core cover 9021 and a second auxiliary magnetic core cover 9022 are included. It should be noted that the first main magnetic core cover 9011 and the first auxiliary magnetic core cover 9012 are integrally formed in the actual object. In FIG.
  • first magnetic core cover 901 and the second magnetic core cover 902 parallel to the magnetic core leg may also be referred to as a side leg of the magnetic core.
  • first magnetic core leg 903-1 and the first magnetic core leg 903-2 are arranged between the first main magnetic core cover 9011 and the second main magnetic core cover 9021, and are perpendicular to the first magnetic core cover 9011 and the second main magnetic core cover 9021.
  • the second magnetic core column 904-1 and the second magnetic core column 904-2 are disposed between the first auxiliary magnetic core cover 9012 and the second auxiliary magnetic core cover 9022, and are perpendicular to the first auxiliary magnetic core cover 9012 and the second auxiliary magnetic core cover 9022.
  • the second auxiliary magnetic core cover 9022 The second auxiliary magnetic core cover 9022 .
  • the top view from the first magnetic core cover 901 to the second magnetic core cover 902 is a top view, and FIG. 9A can also be exemplarily referred to.
  • the area of the first auxiliary magnetic core cover 9012 is smaller than that of the first auxiliary magnetic core cover 9012
  • the area of the first auxiliary magnetic core cover 9012 may also be equal to the area of the first main magnetic core cover 9011. area.
  • first magnetic core cover 901 and the second magnetic core cover 902 can be separated, and the first magnetic core column 903 and the second magnetic core column 904 can also be combined with the first magnetic core cover 901 and the second magnetic core.
  • the disassembly of the cover 902 is divided into two parts.
  • a planar transformer including two pairs of transformer windings provided by the present application can be obtained by setting as follows: a pair of primary windings and secondary windings of transformer windings are arranged on the above-mentioned first magnetic core column 903-1, The primary winding and the secondary winding of another pair of transformer windings are arranged on the column 903-2, and an auxiliary inductance winding is respectively arranged on the second magnetic core column 904-1 and the second magnetic core column 904-2, and the The connection mode of the two auxiliary inductor windings and the two primary windings can be connected by referring to the connection mode shown in FIG. 8( a ) or FIG. 8( b ).
  • the winding direction of the windings in two of the four magnetic core legs is the first direction
  • the winding direction of the other two magnetic core legs is the second direction, which is the same as the second direction.
  • the first direction is the opposite direction. For example, if viewed from the direction from the first magnetic core cover 901 to the second magnetic core cover 902, the first direction is a counterclockwise direction, the second direction is a clockwise direction, or the first direction is a clockwise direction , the second direction is counterclockwise.
  • the magnetic fluxes generated by the windings with the same winding direction are in the same direction, and the magnetic fluxes generated by the windings with opposite winding directions are in the opposite direction.
  • These magnetic fluxes pass through their respective magnetic cores
  • the magnetic flux passing through the magnetic core cover is reduced, so that the thickness of the magnetic core cover can be appropriately reduced, that is, the cross-sectional area of the magnetic flux passing through the magnetic core cover can be reduced. , so that the overall thickness of the planar transformer can be reduced without causing the problem of magnetic saturation of the magnetic core cover.
  • FIG. 10 shows a schematic diagram of the flow of the magnetic flux generated by the auxiliary inductance winding and the primary winding of the transformer after the above-mentioned planar transformer is powered on.
  • the auxiliary inductance winding is not drawn in Figure 10. and the windings of the transformer, but in fact the first magnetic core leg 903-1 and the first magnetic core leg 903-2 are respectively provided with the primary winding and the secondary winding of the transformer, the second magnetic core leg 904-1 and the second Auxiliary inductor windings are respectively provided on the magnetic core legs 904-2.
  • the direction of the magnetic flux generated by the windings in the first magnetic core leg 903-1 and the second magnetic core leg 904-1 is to flow out of the magnetic core leg in the direction of the first magnetic core cover 901, while the first magnetic core leg
  • the direction of the magnetic flux generated by the windings in the magnetic core leg 903 - 2 and the second magnetic core leg 904 - 2 is to flow out of the magnetic core leg toward the direction of the second magnetic core cover 902 .
  • FIG. 10 A portion of the magnetic flux circuit is schematically depicted in FIG. 10 . It should be noted that the direction of the magnetic flux and the magnetic flux circuit shown in FIG. 10 are only an example, and do not constitute a limitation to the present application.
  • the magnetic flux generally chooses the closer magnetic flux loop transmission, in FIG. 10 , most of the magnetic flux generated on the first magnetic core leg 903-1 flows from the first magnetic core leg 903-2 and the magnetic core side legs close to it. and the two loops disperse the magnetic flux generated on the first magnetic core leg 903-1. Similarly, most of the magnetic flux generated on the first magnetic core leg 903-2 flows from the first magnetic core leg 903-1 and its The adjacent core legs flow back, and the two loops disperse the magnetic flux generated on the first core leg 903-2. For the second magnetic core leg 904-1 and the second magnetic core leg 904-2, since the first magnetic core leg and the magnetic core side leg are farther apart, the magnetic flux flowing to the first magnetic core leg and the magnetic core side leg is less.
  • the magnetic flux of the side leg of the magnetic core is less, so a thinner thickness can be designed.
  • the auxiliary inductance winding on the second magnetic core leg produces a reverse magnetic flux offset Part of the magnetic flux can be removed, so its thickness can also be reduced, so that the thickness of the entire magnetic core cover can be reduced.
  • FIG. 11 is a top view of the direction from the first magnetic core cover 901 to the second magnetic core cover 902 in FIG. 10.
  • the black circles in the figure represent the magnetic flux flowing out of the page, and the cross symbol represents the magnetic flux flowing into the page.
  • the dashed arrows indicate the direction of magnetic flux flow.
  • the arrangement of the magnetic core columns shown in FIG. 11 is a matrix arrangement, but in the present application, the arrangement of a plurality of magnetic core columns in the magnetic core may also be other array arrangements, such as diamond arrangement, etc., or It is not limited to the arrangement of the array, and the present application does not limit the arrangement of the plurality of magnetic core columns. It can be seen in FIG.
  • the magnetic flux directions between the two horizontally adjacent and vertically adjacent magnetic core columns are opposite, so that the first magnetic core on the magnetic core cover is in the opposite direction.
  • the direction of the magnetic flux between the core leg 903-1 and the first magnetic core leg 903-2 is opposite to the direction of the magnetic flux between the second magnetic core leg 904-1 and the second magnetic core leg 904-2, so that the The magnetic flux between the second magnetic core leg 904-1 and the second magnetic core leg 904-2 can partially cancel the magnetic flux between the first magnetic core leg 903-1 and the first magnetic core leg 903-2, that is, reducing the Magnetic flux through the core cover.
  • the area where the dotted rectangle frame is located in FIG. 11 is the area where the magnetic fluxes are canceled.
  • two second magnetic core legs may be added.
  • the added two second magnetic core legs Auxiliary inductor windings are likewise provided in each case.
  • the newly added two auxiliary inductance windings are respectively connected in parallel with the primary windings of the transformer T1 and the transformer T2, and the direction of the magnetic flux generated after the auxiliary inductance winding is energized is also connected with the parallel connection of the primary winding.
  • the directions of the magnetic fluxes are reversed, so that the cancellation of the magnetic fluxes can be achieved.
  • the newly added two auxiliary inductance windings continue to be connected in series with the original two auxiliary inductance windings connected in series, and the four auxiliary inductance windings are connected in series and then connected in parallel with the two series-connected primary windings of the transformer. connection, and the direction of the magnetic flux generated by each primary winding is opposite to the direction of the magnetic flux generated by the corresponding two auxiliary inductance windings, so that the cancellation of the magnetic flux can be better achieved.
  • the newly added one of the second magnetic core legs is symmetrical with the second magnetic core 904-1 shown in FIG. 9 with respect to the first magnetic core leg 903-1.
  • the newly added second magnetic core leg is symmetrical with the second magnetic core leg 904-2 shown in FIG. 9 with respect to the first magnetic core leg 903-2.
  • FIG. 12 For ease of understanding, reference may be made to FIG. 12 .
  • FIG. 12 For ease of understanding, reference may be made to FIG. 12 .
  • FIG. 12 is a top view from the first magnetic core cover 901 to the second magnetic core cover 902, and it can be seen that the two newly added second magnetic core legs are the second magnetic core leg 904-3 and the second magnetic core A leg 904-4, the second magnetic core leg 904-3 and the second magnetic core leg 904-1 are symmetrical with respect to the first magnetic core leg 903-1, the second magnetic core leg 904-4 and the second magnetic core leg 904 -2 is symmetrical about the first magnetic core leg 903-2.
  • the direction of the magnetic flux generated on the second magnetic core leg 904-3 is opposite to that of the first magnetic core leg 903-1
  • the direction of the magnetic flux generated on the second magnetic core leg 904-4 is opposite to that of the first magnetic core leg 904-4.
  • the magnetic flux direction of the magnetic core column 903-2 is opposite, which can cancel part of the magnetic flux passing through the magnetic core cover.
  • the area where the dotted rectangle frame is located in FIG. 12 is the area where the magnetic flux is canceled.
  • the present application can provide a planar transformer including n pairs of transformer windings, where n can be an integer greater than 0.
  • n can be an integer greater than 0.
  • FIG. 13 exemplarily shows a circuit schematic diagram of the planar transformer provided by the present application when more than two pairs of transformer windings are included.
  • Figure 13 (a), (b) and (c) show three possible ways of connecting the magnetizing inductance and the auxiliary inductance.
  • the excitation inductances L m′ of n pairs of transformer windings are respectively connected in parallel with an auxiliary inductance L ⁇ to obtain n groups of parallel inductances, and the n groups of parallel inductances are connected in series.
  • the n primary windings of the transformer are respectively connected in parallel with their corresponding auxiliary inductance windings to obtain n groups of parallel windings, and the n groups of parallel windings are then connected in series.
  • n auxiliary inductances L ⁇ are connected in series and then connected in parallel with the excitation inductance of the primary winding of the transformer connected in series.
  • n auxiliary inductance windings are connected in series, n primary windings of the transformer are connected in series, and then the auxiliary inductance windings connected in series are connected in parallel with the primary windings connected in series.
  • connection mode of the n auxiliary inductance windings and the n primary windings of the voltage transformer may also be: part of the auxiliary inductance After the windings are connected in series, they are connected in parallel with part of the primary windings connected in series, and the remaining auxiliary inductance windings are also connected in series with the remaining primary windings connected in series in parallel.
  • the connection mode of the n auxiliary inductance windings and the n primary windings of the voltage transformer may also be: part of the auxiliary inductance After the windings are connected in series, they are connected in parallel with part of the primary windings connected in series, and the remaining auxiliary inductance windings are also connected in series with the remaining primary windings connected in series in parallel.
  • auxiliary inductors may be connected in series and then connected in parallel with p series-connected excitation inductors, and then np auxiliary inductors may be connected in series with np auxiliary inductors.
  • the connected excitation inductors are connected in parallel, and the two sets of parallel connected inductors are then connected in series.
  • This p is an integer greater than 1 and less than n.
  • the direction of the magnetic flux generated in each primary winding is opposite to the direction of the magnetic flux generated by the corresponding auxiliary inductance winding when energized, thereby achieving Part of the magnetic flux cancels out.
  • the magnetic flux in the opposite direction of the magnetic flux can also be generated between the primary windings, so that the magnetic flux passing through the magnetic core cover can be reduced.
  • n is k 2 as an example for further description, where k is an integer greater than 1.
  • the magnetic core still includes the first magnetic core cover and the second magnetic core cover (for example, refer to the first magnetic core cover and the second magnetic core cover shown in the above-mentioned FIG. 10 and the like), which are not shown in FIG. 14 and FIG. 15 .
  • FIG. 14 shows a schematic diagram of the direction of magnetic flux when k is an even number
  • FIG. 14 shows a schematic diagram of the direction of magnetic flux when k is an odd number.
  • the magnetic core columns in the magnetic core can be arranged in a matrix manner, including k 2 first magnetic core columns, and 2*k second magnetic core columns are arranged on opposite sides of the k 2 first magnetic core columns A core column, and k second magnetic core columns are arranged on each side of the two sides.
  • each first magnetic core column is provided with a primary winding and a secondary winding of the transformer
  • each second magnetic core column is provided with an auxiliary inductance winding
  • two horizontally adjacent and vertically adjacent The magnetic fluxes generated by the windings in the magnetic core legs are in opposite directions, so that partial cancellation of the magnetic fluxes can be achieved.
  • FIG. 15 shows a schematic diagram of the direction of magnetic flux when k is an even number
  • FIG. 15 shows a schematic diagram of the direction of magnetic flux when k is an odd number.
  • the first magnetic core column matrix in FIG. 15 is provided with second magnetic core columns all around, and the magnetic fields generated by the windings in the two horizontally adjacent and vertically adjacent magnetic core columns are The direction of the flux is opposite, so that more magnetic flux can be canceled, and the thickness of the magnetic core cover can be designed to be thinner.
  • the area where the dotted rectangle frame in FIG. 15 is located is the area where the magnetic fluxes are canceled.
  • the arrangement of the magnetic core columns shown in the above figures is a matrix arrangement, but in the present application, the arrangement of a plurality of magnetic core columns in the magnetic core may also be other array arrangements, such as diamond-shaped The arrangement, etc., or the arrangement of the array is not limited, and the present application does not limit the arrangement of the plurality of magnetic core columns.
  • the first magnetic core legs are arranged in the preset area, and the second magnetic core legs are distributed outside the preset area.
  • the second magnetic core leg is not limited to being designed at the periphery of the preset area where the first magnetic core leg is located, and the first magnetic core leg can also be designed in the preset area. In the gap between the core columns, or the first magnetic core column and the second magnetic core column are cross-mixed and arranged, and so on.
  • the number of the second magnetic core legs in the above-mentioned FIG. 14 and FIG. 15 may be less than the number of the first magnetic core legs, but the number of auxiliary inductance windings can be arranged on the second magnetic core leg more.
  • the number of turns of the auxiliary inductance winding is set on the second magnetic core leg to increase the generated magnetic flux, so as to achieve the required magnetic flux cancellation on the magnetic core cover.
  • the cross-sectional area of the first magnetic core leg and the second magnetic core leg may be the same, or the cross-sectional area of the second magnetic core leg may be smaller than the cross-sectional area of the first magnetic core leg.
  • the cross-sectional area of the second magnetic core leg is smaller than the cross-sectional area of the first magnetic core leg, the occupied area of the magnetic core can be reduced, and the material cost can be saved.
  • Ae ⁇ Ae m' *N m' /N ⁇ , that is, the cross-sectional area of the second magnetic core leg is N m' /N ⁇ times that of the first magnetic core leg.
  • the number of turns of the auxiliary inductance winding on the second magnetic core leg can be set to be greater than the number of turns of the primary winding on the first magnetic core leg, for example, the number of turns of the auxiliary inductance can be set to be twice the number of turns of the primary winding , 3 times or 4 times, etc. Since the inductance value of the inductance is proportional to the square of the number of turns of the winding, the more the number of turns, the larger the inductance value, the smaller the current flowing through the auxiliary inductance winding, and the smaller the resulting winding loss.
  • auxiliary inductor windings and transformer windings arranged on the magnetic core legs may be wound windings or printed circuit board windings.
  • the design of adding a second magnetic core leg in the magnetic core for setting auxiliary inductance windings to reduce the magnetic flux passing through the magnetic core cover can be applied to various types of magnetic cores, such as ER Type, RM type, EI type, EP type, PQ type or EE type and so on.
  • the above-mentioned embodiments are mainly introduced by taking an ER-type magnetic core as an example, but this does not constitute a limitation to the present application.
  • the shape of the magnetic core column may be a circle, an ellipse, a crescent shape, a polyhedron shape, etc., which is not limited in this application.
  • the primary winding on the first magnetic core column and the auxiliary inductance winding on the second magnetic core column may not be electrically connected, and a power supply may be set as:
  • the primary winding in the first magnetic core leg is energized, and another power supply is provided to energize the auxiliary inductance winding on the second magnetic core leg.
  • This embodiment can also achieve the above-mentioned purpose of canceling the magnetic flux in the magnetic core cover. In some cases, for example, when the wiring of the circuit board is difficult, the embodiments of the present application can provide better flexible wiring.
  • Table 1 can be exemplarily shown, and Table 1 exemplarily shows a comparison of the parameters of a planar transformer provided by the present application with the parameters of an existing planar transformer.
  • the planar transformer provided in this application only increases the total loss by 2%, and the total thickness of the magnetic core can be reduced by 12%, that is, a relatively large amount of loss can be achieved with only a small loss cost. to reduce the thickness of the core.
  • the planar transformer provided by the present application compared with the existing planar transformer, the area occupied by the magnetic core (for example, can be viewed from the direction of the first magnetic core cover to the second magnetic core cover, the first The occupied area of the cover is the occupied area of the magnetic core) is slightly increased, for example, referring to FIG. 4 and FIG.
  • the increase is the occupied area of the first auxiliary magnetic core cover, but in the design of the present application, it is possible to design
  • the occupied area of the first auxiliary magnetic core cover is smaller than that of the first main magnetic core cover, so the increased occupied area of the magnetic core is small, that is, in the present application, only a small occupied area of the magnetic core needs to be paid, that is, The thickness of the magnetic core can be greatly reduced.
  • a second magnetic core column is added for setting the auxiliary inductance winding, so as to generate the magnetic flux opposite to the primary winding of the transformer, thereby reducing the number of passing through the magnetic core
  • the magnetic flux of the cover which in turn can reduce the thickness of the core cover.
  • the present application can reduce the magnetic flux passing through the magnetic core cover in the design of the planar transformer that realizes small current output, and then can design the magnetic core cover with a thinner thickness to avoid It is used to better meet the design of ultra-thin products.
  • the planar transformer with small current output can be, for example, a planar transformer composed of only one or two pairs of transformer windings (for example, any one of the planar transformers provided in the present application described in the above FIGS. 2 to 12 ) or the like.
  • the planar transformer with small current output can also be a planar transformer composed of three pairs of transformer windings, and so on.
  • the present application also provides a circuit board, which includes any one of the above-mentioned planar transformers.
  • the present application also provides an electronic device, which includes any one of the above-mentioned planar transformers.
  • first, second and other words are used to distinguish the same or similar items with basically the same function and function, and it should be understood that between “first”, “second” and “nth” There are no logical or timing dependencies, and no restrictions on the number and execution order. It will also be understood that, although the following description uses the terms first, second, etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another.
  • a first magnetic core cover may be referred to as a second magnetic core cover
  • a second magnetic core cover may be referred to as a first magnetic core cover, without departing from the scope of the various described examples.
  • Both the first core cap and the second core cap may be core caps, and in some cases, may be separate and distinct core caps.
  • the size of the sequence number of each process does not mean the sequence of execution, and the execution sequence of each process should be determined by its function and internal logic, and should not be used in the embodiment of the present application. Implementation constitutes any limitation.
  • references throughout the specification to "one embodiment,” “an embodiment,” and “one possible implementation” mean that a particular feature, structure, or characteristic associated with the embodiment or implementation is included herein. in at least one embodiment of the application. Thus, appearances of "in one embodiment” or “in an embodiment” or “one possible implementation” in various places throughout this specification are not necessarily necessarily referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

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Abstract

本申请提供一种平面变压器及相关设备，该平面变压器包括磁芯，该磁芯包括第一磁芯盖、第二磁芯盖、n个第一磁芯柱和k个第二磁芯柱，该n个第一磁芯柱和k个第二磁芯柱设置在该第一磁芯盖和该第二磁芯盖之间，该n和k均为大于0的整数；该n个第一磁芯柱中每个第一磁芯柱上设置有相互耦合的原边绕组和副边绕组，该k个第二磁芯柱中每个第二磁芯柱上设置有辅助电感绕组；在通电的情况下，第一磁通量在通过该第一磁芯盖和该第二磁芯盖时抵消部分第二磁通量，该第一磁通量为该k个第二磁芯柱上设置的辅助电感绕组产生的磁通量，该第二磁通量为该n个第一磁芯柱上设置的原边绕组产生的磁通量。本申请提供的平面变压器厚度更薄。

Description

平面变压器及相关设备 技术领域
本发明涉及电力电子技术领域，尤其涉及一种平面变压器及相关设备。
背景技术
平面变压器(planar transformer)是一种具有高频，低造型，高度很小而工作频率很高等特点的变压器。变压器是电源中的一个关键元件，传统的变压器通常由铁氧体磁芯及铜线圈构成，体积庞大而且容易产生电磁干扰，而平面变压器可有效地解决体积及高频问题，可以广泛应用于各个领域的电子设备中。
但是随着各种终端产品和电子媒介屏等设备的供电电源不断向小型化和超薄化演进，现有的平面变压器的薄度仍无法满足需求。因此，如何设计厚度更薄的平面变压器是本领域技术人员急需解决的技术问题。
发明内容
本申请公开了一种平面变压器及相关设备，该平面变压器的厚度更薄，可以更好地满足超薄化产品的设计。
第一方面，本申请提供一种平面变压器，包括：磁芯，该磁芯包括第一磁芯盖、第二磁芯盖、n个第一磁芯柱和k个第二磁芯柱，该n个第一磁芯柱和k个第二磁芯柱设置在该第一磁芯盖和该第二磁芯盖之间，该n和k均为大于0的整数；
该n个第一磁芯柱中每个第一磁芯柱上设置有相互耦合的原边绕组和副边绕组，该k个第二磁芯柱中每个第二磁芯柱上设置有辅助电感绕组；
在通电的情况下，第一磁通量在通过该第一磁芯盖和该第二磁芯盖时抵消部分第二磁通量，该第一磁通量为该k个第二磁芯柱上设置的辅助电感绕组产生的磁通量，该第二磁通量为该n个第一磁芯柱上设置的原边绕组产生的磁通量。
在本申请中，通过增加辅助电感绕组来产生磁通量，以使得该磁通量可以在磁芯盖上部分抵消变压器原边绕组的磁通量，从而减少通过磁芯盖的磁通量，进而可以设计出厚度更薄的磁芯盖，以用于更好地满足超薄化产品的设计。
另外，相比于现有的技术方案，本申请可以在实现小电流输出的平面变压器设计中，也可以做到减少通过磁芯盖的磁通量，进而可以设计出厚度更薄的磁芯盖，以用于更好地满足超薄化产品的设计。该小电流输出的平面变压器例如可以是，只有一对或两对变压器绕组(一对变压器绕组包括一个变压器原边绕组和一个变压器副边绕组)组成的平面变压器等。
一种可能的实施方式中，该第一磁芯盖的结构和该第二磁芯盖的结构对称，该第一磁芯盖包括第一主磁芯盖和第一辅助磁芯盖，该第二磁芯盖包括第二主磁芯盖和第二辅助磁芯盖；在从该第一磁芯盖向该第二磁芯盖方向俯视该平面变压器得到的俯视图中，该第一辅助磁芯盖的面积小于该第一主磁芯盖的面积；
该n个第一磁芯柱和k个第二磁芯柱设置在该第一磁芯盖和该第二磁芯盖之间，包括：
该n个第一磁芯柱设置在该第一主磁芯盖和该第二主磁芯盖之间，并垂直与该第一主磁芯盖和该第二主磁芯盖连接；该k个第二磁芯柱设置在该第一辅助磁芯盖和该第二辅助磁芯盖之间，并垂直与该第一辅助磁芯盖和该第二辅助磁芯盖连接。
在本申请中，设计辅助磁芯盖的面积小于主磁芯盖的面积可以使得整体磁芯的占用面积 减少，相比于现有的技术方案，虽然本申请磁芯的整体占用面积增加了辅助磁芯盖的面积，但增加较少，即本申请只需付出较少的磁芯占用面积成本即可设计出厚度更薄的磁芯盖，以用于更好地满足超薄化产品的设计。
一种可能的实施方式中，该第二磁芯柱的横截面积小于该第一磁芯柱的横截面积。
在本申请中，减少第二磁芯柱的横截面积，可以对应地减少磁芯盖的占用面积，进而可以减少整个磁芯的占用面积。
一种可能的实施方式中，该第一磁芯柱和该第二磁芯柱的横截面积之比，等于该第二磁芯柱上辅助电感绕组的匝数与该第一磁芯柱上原边绕组的匝数之比。
在本申请中，若辅助电感绕组和变压器原边绕组产生的磁通量在磁芯柱中传输时的磁通量密度相同，那么，辅助电感绕组和变压器原边绕组之间的匝数比等于变压器原边绕组和辅助电感绕组之间的横截面积之比，即辅助电感绕组和变压器原边绕组之间的匝数比等于该第一磁芯柱和该第二磁芯柱的横截面积之比。即本申请的设计可以使得磁通量均匀传输，以更好地使得副边绕组产生磁感应，以及降低磁芯的损耗。另外，在本申请中，还可以通过控制辅助电感绕组和变压器原边绕组之间的匝数比，来控制第一磁芯柱和该第二磁芯柱的横截面积之比。
一种可能的实施方式中，该辅助电感绕组的匝数大于该原边绕组的匝数。
由于电感感值与匝数的平方成正比，感值越大，则电感电流越小，产生的附加绕组损耗就越小，因此，本申请的设计可以减少辅助电感绕组的损耗。
一种可能的实施方式中，该辅助电感绕组和该原边绕组电连接。
一种可能的实施方式中，该n个第一磁芯柱中的n个原边绕组串联连接；
在该n大于或等于该k的情况下，该n个原边绕组中的k个原边绕组与该k个第二磁芯柱中的k个辅助电感绕组分别并联连接；
或者，在该n小于该k的情况下，该n个原边绕组中的每个该原边绕组与k个该辅助电感绕组中的至少一个并联连接；
或者，该k个第二磁芯柱中的k个辅助电感绕组串联连接后与串联连接的该n个原边绕组并联连接；
或者，k1个该辅助电感绕组串联连接后与串联连接的n1个该原边绕组并联连接，且k2个该辅助电感绕组串联连接后与串联连接的n2个该原边绕组并联连接；其中，k1+k2＝k，n1+n2＝n，k1、k2、n1和n2均为大于0的整数。
一种可能的实施方式中，该辅助电感绕组和该原边绕组解耦或弱耦合。
本申请的设计可以减少辅助电感绕组和变压器原边绕组之间的互感影响。
一种可能的实施方式中，该n个第一磁芯柱以及该k个第二磁芯柱以阵列的形式排布，在由该第一磁芯盖到该第二磁芯盖的方向俯视的情况下，该n个第一磁芯柱以及该k个第二磁芯柱中水平相邻和垂直相邻的两个磁芯柱上绕组的绕线方向相反。
一种可能的实施方式中，该n个第一磁芯柱设置在预设区域内，该k个第二磁芯柱分布在该预设区域外。
本申请的设计可以更好地布线。
第二方面，本申请提供一种电路板，该电路板包括如上述第一方面及其可能的实施方式中任一项所述的平面变压器。
第三方面，本申请提供一种电子设备，该电子设备包括如上述第一方面及其可能的实施 方式中任一项所述的平面变压器。
附图说明
图1所示为本申请提供的平面变压器使用的场景示意图；
图2所示为平面变压器的电路原理图示意图；
图3所示为电感等效示意图；
图4所示为本申请提供的磁芯结构示意图；
图4A所示为本申请提供的磁芯结构的俯视示意图；
图5所示为本申请提供的平面变压器中磁通在磁芯中传输方向的示意图；
图6和图7所示为本申请提供的俯视平面变压器时的磁通传输方向示意图；
图8所示为平面变压器的另一种电路原理图示意图；
图9所示为本申请提供的另一种磁芯结构示意图；
图9A所示为本申请提供的另一种磁芯结构的俯视示意图；
图10所示为本申请提供的另一种平面变压器中磁通在磁芯中传输方向的示意图；
图11和图12所示为本申请提供的另一种俯视平面变压器时的磁通传输方向示意图；
图13所示为平面变压器的另一种电路原理图示意图；
图14和图15所示为本申请提供的另一种俯视平面变压器时的磁通传输方向示意图。
具体实施方式
下面结合附图对本申请的实施例进行描述。
首先介绍一下本申请提供的平面变压器的应用场景，示例性地，该平面变压器可以应用在航空航天电源，舰载电源，雷达电源，通讯电源，电动机车或汽车电源，计算机或集成芯片电源，高频加热或照明电源，变频器，逆变器和各种交流/直流(alternating current/direct current，AC/DC)变换器，DC/DC变换器等装置中。
参见图1，图1示例性示出了该平面变压器应用在上述装置中的电路系统100的示意图。该电路系统100包括输入电路101、平面变压器102和输出电路103。其中，输入电路101可以与电源连接，该电源可以是直流电源或者交流电源。该直流电源例如可以是储能电池(如镍镉电池、镍氢电池、锂离子电池、锂聚合物电池等)或太阳能电池等等。该交流电源可以是220V或380V电网电源等。平面变压器102用于对从输入电路101获得的电压进行变换(例如升压或者降压)，然后，输出电路103将平面变压器102变换后的电压输出到对应的负载上，以为该负载供电。示例性地，该负载例如可以是通讯设备(例如手机)、计算机(例如电脑)或电动车等等。
上述为对本申请提供的平面变压器的应用场景进行示例，而非穷举，应当理解为本申请提供的平面变压器不限于应用在上述电压转换的场景。
下面结合本申请提供的平面变压器的结构进行介绍。
参见图2，图2示例性示出了平面变压器仅包括一对变压器绕组时的电路原理图。一对变压器绕组包括变压器的一个原边绕组和一个副边绕组。
图2中(a)所示为现有的平面变压器的电路原理图，其中，L m是励磁电流I m流过变压器T的原边绕组时产生的励磁电感。为了便于理解本申请的实施例，本申请中将励磁电感L m示例性表示在变压器电路原理图中。
图2中(b)所示为本申请提供的平面变压器的电路原理图，其中，L m’是励磁电流I m’输入变压器T的原边绕组后产生的励磁电感，L σ是电流I σ流过辅助电感绕组时产生的电感，可以称L σ该为辅助电感。该辅助电感绕组与变压器T的原边绕组并联连接。
一种可能的实施方式中，图2的(b)所示的平面变压器中并联的励磁电感L m’和辅助电感L σ等效于上述图2的(a)中所示平面变压器的励磁电感L m。另外，励磁电感L m’和辅助电感L σ之间一般存在互感，示例性的，可以参见图3，图3示例性示出了L m、L m’和L σ之间的关系。在图3中M为励磁电感L m’和辅助电感L σ的互感系数，图3中所示的关系可以通过如下公式来表示：
L m＝L σ//L m’＝(L σ*L m’-M 2)/(L σ+L m’-2*M)
可选的，为了减少互感的影响，可以设计该励磁电感L m’和辅助电感L σ之间为解耦合关系或者弱耦合关系。
一种可能的实施方式中，可以设计电流I σ流过辅助电感绕组时该辅助电感绕组产生的磁链ψ σ，与电流I m’流过变压器T的原边绕组时在该原边绕组产生的磁链ψ m’相等，即
ψ σ＝ψ m’
由于磁通量φ为磁链ψ与绕组的匝数N的比值，那么
φ σ＝ψ σ/N σ
φ m’＝ψ m’/N m’
φ σ为电流I σ流过辅助电感绕组时该辅助电感绕组的磁通量，φ m’为电流I m’流过变压器T的原边绕组时在该原边绕组的磁通量，N σ为辅助电感绕组的匝数，N m’为变压器T的原边绕组的匝数。可以看到，在辅助电感绕组和变压器T的原边绕组的磁链相等时，可以得到：
φ σ/φ m’＝N m’/N σ
即可以通过控制绕组的匝数比来控制辅助电感绕组和变压器T的原边绕组的磁通比。
又由于磁通密度B为磁通量φ与该磁通量φ垂直通过的面积Ae的比值，那么
B σ＝φ σ/Ae σ
B m’＝φ m’/Ae m’
B σ为电流I σ流过辅助电感绕组时该辅助电感绕组的磁通量φ σ垂直通过面积Ae σ时的磁通密度，B m’为电流I m’流过变压器T的原边绕组时该原边绕组的磁通量φ m’垂直通过面积Ae m’时的磁通密度。为了磁通量的均匀传输，可以取B σ＝B m’，那么φ σ/Ae σ＝φ m’/Ae m’，即φ σ/φ m’＝Ae σ/Ae m’，即N m’/N σ＝Ae σ/Ae m’。这表明，在磁通密度相等时，可以通过控制绕组的匝数比来控制辅助电感绕组和变压器T的原边绕组的横截面积的大小。
基于上述图2，或者图2和图3介绍的原理，可以设计本申请提供的平面变压器的磁芯，参见图4。图4示例性示出了本申请实施例提供的一种平面变压器的磁芯400的结构。该磁芯400包括第一磁芯盖401、第二磁芯盖402、第一磁芯柱403和第二磁芯柱404。其中，第一磁芯盖401的结构和第二磁芯盖402的结构对称，第一磁芯盖401包括第一主磁芯盖4011和第一辅助磁芯盖4012，第二磁芯盖402包括第二主磁芯盖4021和第二辅助磁芯盖4022。需要说明的是，第一主磁芯盖4011和第一辅助磁芯盖4012在具体实物中是一体成型的，图4中该第一主磁芯盖4011和第一辅助磁芯盖4012之间画了一条虚线是为了便于区分这两部分；同理，需要说明的是，第二主磁芯盖4021和第二辅助磁芯盖4022在具体实物中是一体成型的，图4中该第二主磁芯盖4021和第二辅助磁芯盖4022之间画了一条虚线是为了便于区分这两部分。相比于现有的磁芯，图4所示结构中多了第一辅助磁芯盖4012、第二辅助磁 芯盖4022和第二磁芯柱404。该增加的第二磁芯柱404的作用下面会详细介绍，此处暂不赘述。
此外，第一磁芯盖401和第二磁芯盖402中与磁芯柱平行的部分也可以称为磁芯的边柱。
在图4中可以看到，第一磁芯柱403设置在第一主磁芯盖4011和第二主磁芯盖4021之间，并垂直与该第一主磁芯盖4011和第二主磁芯盖4021。而第二磁芯柱404设置在第一辅助磁芯盖4012和第二辅助磁芯盖4022之间，并垂直与该第一辅助磁芯盖4012和第二辅助磁芯盖4022。
另外，在图4中，从第一磁芯盖401向第二磁芯盖402的方向俯视得到的俯视图中，示例性地可以参见图4A，第一辅助磁芯盖4012的面积小于第一主磁芯盖4011的面积。
一种可能的实施方式中，从第一磁芯盖401向第二磁芯盖402的方向俯视得到的俯视图中，第一辅助磁芯盖4012的面积也可以等于第一主磁芯盖4011的面积。
可选的，第一磁芯盖401和第二磁芯盖402可以拆分开，第一磁芯柱403和第二磁芯柱404也可以随着第一磁芯盖401和第二磁芯盖402的拆开而拆分成两部分。
在上述磁芯400中的第一磁芯柱403上设置变压器的原边绕组和副边绕组，同时在该磁芯400中的第二磁芯柱404上设置辅助电感绕组，且该辅助电感绕组和该原边绕组并联连接，该辅助电感绕组的绕线方向和该原边绕组的绕线相反，这就得到了本申请提供的一种平面变压器。
该辅助电感绕组的绕线方向和该原边绕组的绕线例如可以是，从第一磁芯盖401向第二磁芯盖402的方向俯视该辅助电感绕组的绕线方向为顺时针方向，同时俯视该原边绕组的绕线方向为逆时针方向；或者，从第一磁芯盖401向第二磁芯盖402的方向俯视该辅助电感绕组的绕线方向为逆时针方向，同时俯视该原边绕组的绕线方向为顺时针方向。
在给该平面变压器接通电源后，由于该辅助电感绕组和该原边绕组并联连接且绕组的绕线方向相反，因此该辅助电感绕组和该原边绕组产生的磁通方向相反，该两个绕组产生的磁通经过各自的磁芯柱传输到磁芯盖时，由于方向相反可以部分抵消，减少了通过磁芯盖的磁通量。由于磁通密度B为磁通量φ与该磁通量φ垂直通过的面积Ae的比值，因此，在磁芯盖中的磁通量减少的情况下，可以适当降低磁芯盖的厚度，即减小磁芯盖中磁通量通过的横截面积，这样既可以降低了平面变压器的整体厚度，又不会导致磁芯盖的磁通密度增大带来的磁饱和的问题。
示例性地，可以参见图5和图6。图5中画出了给上述平面变压器接通电源后辅助电感绕组和变压器的原边绕组产生的磁通的流向示意图，需要说明的是，为了示意图的简洁，图5中没有画出辅助电感绕组和变压器的绕组，但实际上第一磁芯柱403中设置有变压器的原边绕组和副边绕组，第二磁芯柱404上设置有辅助电感绕组。可以看到，原边绕组产生的磁通通过第一磁芯盖401和第二磁芯盖402形成了两个磁通回路，同样的，辅助电感绕组产生的磁通通过第一磁芯盖401和第二磁芯盖402也形成了两个磁通回路。并且原边绕组和辅助电感绕组的磁通在磁芯盖中的磁通方向总是相反的，因此，在磁芯盖中辅助电感绕组的磁通量可以部分抵消原边绕组的磁通量。图6所示为从第一磁芯盖401到第二磁芯盖402的方向俯视图，图中的黑圆点表示磁通流出页面，交叉符号表示磁通流入页面，箭头表示磁通流通的方向，即第一磁芯柱403的磁通方向与第二磁芯柱404的磁通方向相反，虚线框起来的是磁通相消的区域。
一种可能的实施方式中，基于图4所示的磁芯400，还可以再增加一个第二磁芯柱404， 在本申请提供的平面变压器中，该增加的第二磁芯柱404同样设置有辅助电感绕组，该辅助电感绕组也与变压器的原边绕组并联连接，且该辅助电感绕组通电后产生的磁通的方向也与第一磁芯柱403中变压器原边绕组产生的磁通的方向相反，进而可以实现磁通的相消。可选的，该新增的第二磁芯柱404与图4中所示的第二磁芯404关于第一磁芯柱403对称。为了便于理解，可以参见图7。图7所示为从第一磁芯盖401到第二磁芯盖402的方向俯视图，可以看到两个第二磁芯柱404对称设置在第一磁芯柱403的两侧，且该两个第二磁芯柱404的磁通方向与第一磁芯柱403的磁通方向相反，可以消除部分通过磁芯盖的磁通量。
可选的，图7所示的平面变压器相比于图6所示的变压器，图7中两个第二磁芯柱404中设置的辅助电感绕组的总匝数可以和图6中一个第二磁芯柱404上设置的辅助电感绕组的匝数相等。例如，假设图6中一个第二磁芯柱404上设置的辅助电感绕组的匝数为N1，图7中一个第二磁芯柱404中设置的辅助电感绕组的匝数为N1/2，另一个第二磁芯柱404中设置的辅助电感绕组的匝数也是N1/2。基于上述φ σ/φ m’＝N m’/N σ可知，辅助电感绕组的匝数可以根据需要的磁通量来确定，本申请对辅助电感绕组的具体匝数不做限制。
上面介绍的是平面变压器仅包括一对变压器绕组时的情况，下面介绍平面变压器包括两对变压器绕组时的情况。
参见图8，图8示例性示出了本申请提供的包括两对变压器绕组时的平面变压器的电路原理图。图8中的(a)和(b)示出了两种可能的励磁电感和辅助电感连接方式，其中，图8的(a)中两对变压器绕组的励磁电感L m’分别与一个辅助电感L σ并联，变压器T1的励磁电感L m’与辅助电感L σ并联后再与并联连接的变压器T2的励磁电感L m’与辅助电感L σ串联连接。在具体实物连接时，则是一个或多个辅助电感绕组和变压器T1的原边绕组并联连接，另外的一个或多个辅助电感绕组和变压器T2的原边绕组并联连接，然后再将该并联连接的绕组对串联连接。
图8的(b)中则是两个辅助电感L σ串联后再与串联连接的变压器T1和变压器T2的励磁电感L m’并联连接。在具体实物连接时，则是至少两个辅助电感绕组串联连接，两个变压器的原边绕组串联连接，然后串联连接的辅助电感绕组再与串联连接的原边绕组并联连接。
不管是图8的(a)所示的连接方式，还是图8的(b)所示的连接方式，一种可能的实施方式中，在通电时，每个原边绕组中产生的磁通的方向均与对应的辅助电感绕组产生的磁通的方向相反，进而实现磁通的部分相消。
基于上述图8介绍的原理，可以设计本申请提供的平面变压器的磁芯，参见图9。图9示例性示出了本申请实施例提供的一种平面变压器的磁芯900的结构。该磁芯900包括第一磁芯盖901、第二磁芯盖902、两个第一磁芯柱(903-1和903-2，下面可以统称第一磁芯柱903-1和第一磁芯柱903-2为第一磁芯柱903)以及两个第二磁芯柱(904-1和904-2，下面可以统称第二磁芯柱904-1和第二磁芯柱904-2为第二磁芯柱904)。其中，第一磁芯盖901的结构和第二磁芯盖902的结构对称，第一磁芯盖901包括第一主磁芯盖9011和第一辅助磁芯盖9012，第二磁芯盖902包括第二主磁芯盖9021和第二辅助磁芯盖9022。需要说明的是，第一主磁芯盖9011和第一辅助磁芯盖9012在具体实物中是一体成型的，图9中该第一主磁芯盖9011和第一辅助磁芯盖9012之间画了一条虚线是为了便于区分这两部分；同理，需要说明的是，第二主磁芯盖9021和第二辅助磁芯盖9022在具体实物中是一体成型的，图9中该第二主磁芯盖9021和第二辅助磁芯盖9022之间画了一条虚线是为了便于区分这两部分。相比于现有 的磁芯，图9所示结构中多了第一辅助磁芯盖9012、第二辅助磁芯盖9022和第二磁芯柱904。该增加的第二磁芯柱904的作用下面会详细介绍，此处暂不赘述。
此外，第一磁芯盖901和第二磁芯盖902中与磁芯柱平行的部分也可以称为磁芯的边柱。
在图9中可以看到，第一磁芯柱903-1和第一磁芯柱903-2设置在第一主磁芯盖9011和第二主磁芯盖9021之间，并垂直与该第一主磁芯盖9011和第二主磁芯盖9021。而第二磁芯柱904-1和第二磁芯柱904-2设置在第一辅助磁芯盖9012和第二辅助磁芯盖9022之间，并垂直与该第一辅助磁芯盖9012和第二辅助磁芯盖9022。
另外，在图9中，从第一磁芯盖901向第二磁芯盖902的方向俯视得到的俯视图中，示例性地也可以参考图9A，第一辅助磁芯盖9012的面积小于第一主磁芯盖9011的面积。
一种可能的实施方式中，从第一磁芯盖901向第二磁芯盖902的方向俯视得到的俯视图中，第一辅助磁芯盖9012的面积也可以等于第一主磁芯盖9011的面积。
可选的，第一磁芯盖901和第二磁芯盖902可以拆分开，第一磁芯柱903和第二磁芯柱904也可以随着第一磁芯盖901和第二磁芯盖902的拆开而拆分成两部分。
本申请提供的一种包括两对变压器绕组的平面变压器可以通过如下设置得到：在上述第一磁芯柱903-1上设置一对变压器绕组的原边绕组和副边绕组，在第一磁芯柱903-2上设置另一对变压器绕组的原边绕组和副边绕组，同时在上述第二磁芯柱904-1和第二磁芯柱904-2上分别设置一个辅助电感绕组，且该两个辅助电感绕组和该两个原边绕组的连接方式可以参见上述图8的(a)或图8的(b)所示的连接方式进行连接。不管采用哪种连接方式，四个磁芯柱中有两个磁芯柱中绕组的绕线方向为第一方向，另外两个磁芯柱的绕线方向为第二方向，该第二方向与第一方向为相反的方向。例如，若从第一磁芯盖901到第二磁芯盖902的方向俯视，那么该第一方向为逆时针方向，该第二方向为顺时针方向，或者，该第一方向为顺时针方向，该第二方向为逆时针方向。
在给上述包括两对变压器绕组的平面变压器接通电源后，绕线方向相同的绕组产生的磁通方向相同，绕线方向相反的绕组产生的磁通方向相反，这些磁通经过各自的磁芯柱传输到磁芯盖时，由于方向相反的磁通可以部分抵消，减少了通过磁芯盖的磁通量，从而可以适当降低磁芯盖的厚度，即减小磁芯盖中磁通量通过的横截面积，这样既可以降低了平面变压器的整体厚度，又不会导致磁芯盖的磁饱和的问题。
示例性地，可以参见图10。图10中画出了给上述平面变压器接通电源后辅助电感绕组和变压器的原边绕组产生的磁通的流向示意图，需要说明的是，为了示意图的简洁，图10中没有画出辅助电感绕组和变压器的绕组，但实际上第一磁芯柱903-1和第一磁芯柱903-2中各自设置有变压器的原边绕组和副边绕组，第二磁芯柱904-1和第二磁芯柱904-2上各自设置有辅助电感绕组。
在图10中可以看到，第一磁芯柱903-1和第二磁芯柱904-1中绕组产生的磁通方向是向第一磁芯盖901的方向流出磁芯柱，而第一磁芯柱903-2和第二磁芯柱904-2中绕组产生的磁通方向是向第二磁芯盖902的方向流出磁芯柱。由于除了上第二磁芯盖之间可以为磁通提供磁通回路之外，除了产生磁通的磁芯柱之外的其它的磁芯柱也可以为该产生的磁通提供磁通回路，因此流出磁芯柱的磁通可以通过多个路径流回该磁芯柱，即一个磁芯柱上产生的磁通在磁芯上可以有多个磁通回路。图10中示例性地画出了部分的磁通回路。需要说明的是，图10中所示出的磁通的方向和磁通回路仅为一个示例，不构成对本申请的限制。
由于磁通量一般选择较近的磁通回路传输，因此在图10中，第一磁芯柱903-1上产生的 磁通量大部分从第一磁芯柱903-2和与其靠近的磁芯边柱流回，并且该两个回路分散了第一磁芯柱903-1上产生的磁通量，同理，第一磁芯柱903-2上产生的磁通量大部分从第一磁芯柱903-1和与其靠近的磁芯边柱流回，并且该两个回路分散了第一磁芯柱903-2上产生的磁通量。而对于第二磁芯柱904-1和第二磁芯柱904-2，由于第一磁芯柱和磁芯边柱较远，流向第一磁芯柱和磁芯该边柱的磁通量较少，因此，第二磁芯柱904-1上产生的磁通量大部分经第二磁芯柱904-2流回，第二磁芯柱904-2上产生的磁通量大部分经第二磁芯柱904-1流回。这样磁芯边柱的磁通量较少，因此可以设计较薄的厚度，对于磁芯盖中磁通量较多的部分，本申请中通过第二磁芯柱上的辅助电感绕组产生反向的磁通抵消掉部分的磁通量，因此也可以降低其厚度，从而使得整个磁芯盖的厚度均可以降低。该原理适用于本申请提供的其它的磁芯结构，此处只是以图10所示磁芯结构为例说明。
参见图11，图11所示为图10中从第一磁芯盖901到第二磁芯盖902的方向俯视图，图中的黑圆点表示磁通流出页面，交叉符号表示磁通流入页面，虚框箭头表示磁通流通的方向。图11中所示的磁芯柱的排列方式为矩阵的排列方式，但在本申请中磁芯中多个磁芯柱的排列方式也可以是其它的阵列排列方式，例如菱形排列方式等，或者也不限于是阵列的排列方式，本申请对多个磁芯柱的排列方式不做限制。在图11中可以看到，以矩阵形式排列的4个磁芯柱中，水平相邻以及垂直相邻的两个磁芯柱之间的磁通方向相反，使得在磁芯盖上第一磁芯柱903-1和第一磁芯柱903-2之间的磁通方向，与第二磁芯柱904-1和第二磁芯柱904-2之间的磁通方向相反，从而可以使得第二磁芯柱904-1和第二磁芯柱904-2之间的磁通量，可以部分抵消第一磁芯柱903-1和第一磁芯柱903-2之间的磁通量，即减少了通过磁芯盖的磁通量。图11中虚线矩形框所在的区域即为磁通量抵消的区域。
一种可能的实施方式中，基于图9所示的磁芯900，还可以在再增加两个第二磁芯柱，在本申请提供的平面变压器中，该增加的两个第二磁芯柱同样各自设置有辅助电感绕组。
可选的，该新增的两个辅助电感绕组分别与变压器T1和变压器T2的原边绕组并联连接，且该辅助电感绕组通电后产生的磁通的方向也与并联连接的原边绕组产生的磁通的方向相反，进而可以实现磁通的相消。
或者，可选的，该新增的两个辅助电感绕组继续与原来串联连接的两个辅助电感绕组串联连接，该四个辅助电感绕组串联连后再与串联连接的两个变压器原边绕组并联连接，且每个原边绕组产生的磁通的方向与对应的两个辅助电感绕组产生的磁通方向相反，进而可以更好地实现磁通的相消。
关于辅助电感绕组的匝数的设置，同样的可以基于上述等式φ σ/φ m’＝N m’/N σ，根据需要的磁通量来确定，本申请对辅助电感绕组的具体匝数不做限制。
可选的，该新增的其中一个第二磁芯柱与图9中所示的第二磁芯904-1关于第一磁芯柱903-1对称。该新增的另一个第二磁芯柱与图9中所示的第二磁芯904-2关于第一磁芯柱903-2对称。为了便于理解，可以参见图12。图12所示为从第一磁芯盖901到第二磁芯盖902的方向俯视图，可以看到新增的两个第二磁芯柱为第二磁芯柱904-3和第二磁芯柱904-4，该第二磁芯柱904-3与第二磁芯柱904-1关于第一磁芯柱903-1对称，该第二磁芯柱904-4与第二磁芯柱904-2关于第一磁芯柱903-2对称。并且，该第二磁芯柱904-3上产生的磁通方向与第一磁芯柱903-1的磁通方向相反，该第二磁芯柱904-4上产生的磁通方向与第一磁芯柱903-2的磁通方向相反，可以消除部分通过磁芯盖的磁通量，图12中虚线矩形框所在的区域即为磁通量抵消的区域。
本申请可以提供包括n对变压器绕组的平面变压器，该n可以是大于0的整数，n为1时则是上述图2至图7中介绍的平面变压器，n为2时则是上述图8至图12中介绍的平面变压器。
参见图13，图13示例性示出了本申请提供的包括2对以上变压器绕组时的平面变压器的电路原理图。图13中的(a)、(b)和(c)示出了三种可能的励磁电感和辅助电感连接方式。其中，图13的(a)中n对变压器绕组的励磁电感L m’分别与一个辅助电感L σ并联得到n组并联电感，该n组并联电感在串联连接。在具体实物连接时，则是变压器的n个原边绕组分别与各自对应的辅助电感绕组并联后得到n组并联绕组，该n组并联绕组再串联连接。
图13的(b)中则是n个辅助电感L σ串联后再与串联连接的变压器原边绕组的励磁电感并联连接。在具体实物连接时，则是n个辅助电感绕组串联连接，变压器的n个原边绕组串联连接，然后串联连接的辅助电感绕组再与串联连接的原边绕组并联连接。
除了上述图13中的(a)和(b)所示的连接方式，一种可能的实施方式中，n个辅助电感绕组和n个电压器原边绕组的连接方式还可以是：部分辅助电感绕组串联连接后再与部分串联连接的原边绕组并联连接，剩余部分的辅助电感绕组也串联连接后与串联连接后的其余原边绕组并联连接。为了便于理解，可以示例性地参见图13的(c)，可以看到，变压器T1的励磁电感L m’与一个辅助电感L σ并联连接，然后，剩下的n-1个辅助电感L σ串联连接，变压器T2至变压器Tn的励磁电感L m’串联连接，该串联连接后的辅助电感L σ再与串联连接后的励磁电感L m’并联连接，该两组并联连接的电感再串联连接。图13的(c)所示的连接方式仅为一个示例，也可以是p个辅助电感串联连接后与p个串联连接的励磁电感并联连接，然后，n-p个辅助电感串联连接后与n-p个串联连接的励磁电感并联连接，该两组并联连接的电感再串联连接。该p为大于1小于n的整数。具体实物连接时，辅助电感替换为上述辅助电感绕组，励磁电感替换为变压器原边绕组即可。
不管是上述的哪种连接方式，一种可能的实施方式中，在通电时，每个原边绕组中产生的磁通的方向均与对应的辅助电感绕组产生的磁通的方向相反，进而实现磁通的部分相消。另外，原边绕组之间也可以产生的磁通方向相反的磁通，从而可以减少通过磁芯盖的磁通量。为了便于理解，示例性地，下面以n为k 2为例进一步介绍，该k为大于1的整数。参见图14和图15，图14和图15所示为磁芯中第一磁芯柱和第二磁芯柱中磁通量方向的示意图，需要说明的是，该磁芯依然包括第一磁芯盖和第二磁芯盖(可以示例性地参见上述图10等所示的第一磁芯盖和第二磁芯盖)，图14和图15中未示出。
首先参见图14，图14中的(a)所示为k是偶数时的磁通量方向示意图，图14中的(b)所示为k是奇数时的磁通量方向示意图。可以看到，磁芯中的磁芯柱可以呈矩阵方式排列，包括k 2个第一磁芯柱，在该k 2个第一磁芯柱相对的两侧设置有2*k个第二磁芯柱，该两侧的每一侧设置k个第二磁芯柱。其中，每个第一磁芯柱上设置有变压器的一个原边绕组和一个副边绕组，每个第二磁芯柱上设置有一个辅助电感绕组，且水平相邻和垂直相邻的两个磁芯柱中的绕组产生的磁通方向相反，从而可以实现磁通的部分相消，图14中虚线矩形框所在的区域即为磁通量抵消的区域。
参见图15，图15中的(a)所示为k是偶数时的磁通量方向示意图，图15中的(b)所示为k是奇数时的磁通量方向示意图。可以看到，相比于图14，图15中第一磁芯柱矩阵的四周均设置有第二磁芯柱，且水平相邻和垂直相邻的两个磁芯柱中的绕组产生的磁通方向相 反，从而可以抵消更多的磁通量，进而可以将磁芯盖的厚度设计得更薄。图15中虚线矩形框所在的区域即为磁通量抵消的区域。
需要说明的是，上述图中所示的磁芯柱的排列方式为矩阵的排列方式，但在本申请中磁芯中多个磁芯柱的排列方式也可以是其它的阵列排列方式，例如菱形排列方式等，或者也不限于是阵列的排列方式，本申请对多个磁芯柱的排列方式不做限制。
在上述的实施例中，可以看到第一磁芯柱设置在预设区域内，第二磁芯柱分布在该预设区域外。一种可能的实施方式中，本申请提供的平面变压器中，第二磁芯柱不限于设计在第一磁芯柱所在的预设区域的外围，也可以设计在该预设区域内第一磁芯柱之间的间隙中，或者第一磁芯柱和第二磁芯柱交叉混合排列等等。
一种可能的实施方式中，上述图14和图15中第二磁芯柱的数量可能少于第一磁芯柱的数量，但是可以通过在第二磁芯柱上多设置辅助电感绕组的个数，或者在第二磁芯柱上多设置辅助电感绕组的匝数来增加产生的磁通量，从而在磁芯盖上达到需要的磁通相消。
一种可能的实施方式中，上述第一磁芯柱和第二磁芯柱的横截面积可以相同，或者，第二磁芯柱的横截面积可以小于第一磁芯柱的横截面积。在第二磁芯柱的横截面积小于第一磁芯柱的横截面积的情况下，可以减少磁芯的占用面积，节省材料成本。
一种可能的实施方式中，由上述原理介绍的内容可知，为了磁通量的均匀传输，取B σ＝B m’，即第一磁芯柱和第二磁芯柱上绕组产生的磁通密度相同，此时N m’/N σ＝Ae σ/Ae m’，即第二磁芯柱和第一磁芯柱的横截面积之比等于第二磁芯柱上辅助电感绕组的匝数与第一磁芯柱上原边绕组的匝数之比。因此，Ae σ＝Ae m’*N m’/N σ，即第二磁芯柱的横截面积为第一磁芯柱的N m’/N σ倍。例如，假设N m’＝18，N σ＝54，N m’/N σ＝1/3，即第二磁芯柱的横截面积为第一磁芯柱的1/3。
在本申请中，可以设置第二磁芯柱上的辅助电感绕组的匝数大于第一磁芯柱上原边绕组的匝数，例如可以设置辅助电感的匝数是原边绕组匝数的2倍、3倍或4倍等等。由于电感感值与绕组匝数的平方成正比，匝数越多，感值越大，则流经辅助电感绕组的电流越小，产生的绕组损耗就越小。
一种可能的实施方式中，上述在磁芯柱上设置的辅助电感绕组和变压器绕组可以是绕线式绕组或印刷电路板绕组。
需要说明的是，本申请提供的在磁芯中增加第二磁芯柱用于设置辅助电感绕组，以减少通过磁芯盖的磁通的设计，可以应用于各种类型的磁芯，例如ER型、RM型、EI型、EP型、PQ型或EE型等等。上述所示实施例主要是以ER型磁芯为例介绍，但这并不构成对本申请的限制。另外，可选的，磁芯柱的形状可以是圆形、椭圆形、月牙形、多面形等，本申请对此不做限制。
一种可能的实施方式中，本申请提供的平面变压器中，上述第一磁芯柱上的原边绕组和第二磁芯柱上的辅助电感绕组之间可以不电连接，可以设置一个电源为第一磁芯柱中的原边绕组通电，设置另一个电源为第二磁芯柱上的辅助电感绕组通电，这种实施方式也可以实现上述在磁芯盖中的磁通相消的目的。本申请实施例可以在一些情况下，例如在电路板布线有困难的情况下，可以更好地灵活布线。
另外，示例性地可以参见表1，表1示例性示出了本申请提供的一种平面变压器的参数与现有的平面变压器的参数的比较。
表1
维度 现有的平面变压 本申请提供的平 降幅
   器的参数 面变压器的参数  
磁芯总厚度 9.7毫米(mm) 8.5mm 下降12％
磁芯盖厚度 2.9mm 2.3mm  
变压器总损耗 2.56瓦(W) 2.61W 上升2％
磁芯损耗 1.8W 1.85W  
绕组损耗 0.76W 0.76W  
在表1中可以看到，本申请提供的平面变压器只增加了2％的总损耗，即可获得磁芯总厚度下降12％，即只需付出较小的损耗成本，即可实现较大幅度地降低磁芯的厚度。
此外，本申请提供的平面变压器，相比于现有的平面变压器，其磁芯的占用面积(示例性地，可以从第一磁芯盖向第二磁芯盖的方向俯视，第一磁芯盖的占用面积即为磁芯的占用面积)稍有增加，例如示例性地参见图4和图9，增加的即为第一辅助磁芯盖的占用面积，但是在本申请设计中，可以设计该第一辅助磁芯盖的占用面积小于第一主磁芯盖的占用面积，那么磁芯增加的占用面积较小，即在本申请中，只需付出较小的磁芯占用面积成本，即可实现较大幅度地降低磁芯的厚度。
综上所述，本申请中，相比于现有的平面变压器，增加了第二磁芯柱用于设置辅助电感绕组，以产生与变压器原边绕组相反的磁通，从而减少了经过磁芯盖的磁通量，进而可以降低磁芯盖的厚度。
另外，相比于现有的技术方案，本申请可以在实现小电流输出的平面变压器设计中，也可以做到减少通过磁芯盖的磁通量，进而可以设计出厚度更薄的磁芯盖，以用于更好地满足超薄化产品的设计。该小电流输出的平面变压器例如可以是，只有一对或两对变压器绕组组成的平面变压器(例如上述图2至图12所述的任一个本申请提供的平面变压器)等。当然，小电流输出的平面变压器也可以是有三对变压器绕组组成的平面变压器等等。
本申请还提供一种电路板，该电路板包括上述介绍的任意一种平面变压器。
本申请还提供一种电子设备，该电子设备包括上述介绍的任意一种平面变压器。
本申请中术语“第一”“第二”等字样用于对作用和功能基本相同的相同项或相似项进行区分，应理解，“第一”、“第二”、“第n”之间不具有逻辑或时序上的依赖关系，也不对数量和执行顺序进行限定。还应理解，尽管以下描述使用术语第一、第二等来描述各种元素，但这些元素不应受术语的限制。这些术语只是用于将一元素与另一元素区别分开。例如，在不脱离各种所述示例的范围的情况下，第一磁芯盖可以被称为第二磁芯盖，并且类似地，第二磁芯盖可以被称为第一磁芯盖。第一磁芯盖和第二磁芯盖都可以是磁芯盖，并且在某些情况下，可以是单独且不同的磁芯盖。
还应理解，在本申请的各个实施例中，各个过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
还应理解，术语“包括”(也称“includes”、“including”、“comprises”和/或“comprising”)当在本说明书中使用时指定存在所陈述的特征、整数、步骤、操作、元素、和/或部件，但是并不排除存在或添加一个或多个其他特征、整数、步骤、操作、元素、部件、和/或其分组。
还应理解，说明书通篇中提到的“一个实施例”、“一实施例”、“一种可能的实现方式”意味着与实施例或实现方式有关的特定特征、结构或特性包括在本申请的至少一个实施例中。 因此，在整个说明书各处出现的“在一个实施例中”或“在一实施例中”、“一种可能的实现方式”未必一定指相同的实施例。此外，这些特定的特征、结构或特性可以任意适合的方式结合在一个或多个实施例中。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (12)

  1. 一种平面变压器，其特征在于，包括：磁芯，所述磁芯包括第一磁芯盖、第二磁芯盖、n个第一磁芯柱和k个第二磁芯柱，所述n个第一磁芯柱和k个第二磁芯柱设置在所述第一磁芯盖和所述第二磁芯盖之间，所述n和k均为大于0的整数；
    所述n个第一磁芯柱中每个第一磁芯柱上设置有相互耦合的原边绕组和副边绕组，所述k个第二磁芯柱中每个第二磁芯柱上设置有辅助电感绕组；
    在通电的情况下，第一磁通量在通过所述第一磁芯盖和所述第二磁芯盖时抵消部分第二磁通量，所述第一磁通量为所述k个第二磁芯柱上设置的辅助电感绕组产生的磁通量，所述第二磁通量为所述n个第一磁芯柱上设置的原边绕组产生的磁通量。
  2. 根据权利要求1所述的平面变压器，其特征在于，所述第一磁芯盖的结构和所述第二磁芯盖的结构对称，所述第一磁芯盖包括第一主磁芯盖和第一辅助磁芯盖，所述第二磁芯盖包括第二主磁芯盖和第二辅助磁芯盖；在从所述第一磁芯盖向所述第二磁芯盖方向俯视所述平面变压器得到的俯视图中，所述第一辅助磁芯盖的面积小于所述第一主磁芯盖的面积；
    所述n个第一磁芯柱和k个第二磁芯柱设置在所述第一磁芯盖和所述第二磁芯盖之间，包括：
    所述n个第一磁芯柱设置在所述第一主磁芯盖和所述第二主磁芯盖之间，并垂直与所述第一主磁芯盖和所述第二主磁芯盖连接；所述k个第二磁芯柱设置在所述第一辅助磁芯盖和所述第二辅助磁芯盖之间，并垂直与所述第一辅助磁芯盖和所述第二辅助磁芯盖连接。
  3. 根据权利要求1或2所述的平面变压器，其特征在于，所述第二磁芯柱的横截面积小于所述第一磁芯柱的横截面积。
  4. 根据权利要求1至3任一项所述的平面变压器，其特征在于，所述第一磁芯柱和所述第二磁芯柱的横截面积之比，等于所述第二磁芯柱上辅助电感绕组的匝数与所述第一磁芯柱上原边绕组的匝数之比。
  5. 根据权利要求1至4任一项所述的平面变压器，其特征在于，所述辅助电感绕组的匝数大于所述原边绕组的匝数。
  6. 根据权利要求1至5任一项所述的平面变压器，其特征在于，所述辅助电感绕组和所述原边绕组电连接。
  7. 根据权利要求6所述的平面变压器，其特征在于，所述n个第一磁芯柱中的n个原边绕组串联连接；
    在所述n大于或等于所述k的情况下，所述n个原边绕组中的k个原边绕组与所述k个第二磁芯柱中的k个辅助电感绕组分别并联连接；
    或者，在所述n小于所述k的情况下，所述n个原边绕组中的每个所述原边绕组与k个 所述辅助电感绕组中的至少一个并联连接；
    或者，所述k个第二磁芯柱中的k个辅助电感绕组串联连接后与串联连接的所述n个原边绕组并联连接；
    或者，k1个所述辅助电感绕组串联连接后与串联连接的n1个所述原边绕组并联连接，且k2个所述辅助电感绕组串联连接后与串联连接的n2个所述原边绕组并联连接；其中，k1+k2＝k，n1+n2＝n，k1、k2、n1和n2均为大于0的整数。
  8. 根据权利要求1至7任一项所述的平面变压器，其特征在于，所述辅助电感绕组和所述原边绕组解耦或弱耦合。
  9. 根据权利要求1至8任一项所述的平面变压器，其特征在于，所述n个第一磁芯柱以及所述k个第二磁芯柱以阵列的形式排布，在由所述第一磁芯盖到所述第二磁芯盖的方向俯视的情况下，所述n个第一磁芯柱以及所述k个第二磁芯柱中水平相邻和垂直相邻的两个磁芯柱上绕组的绕线方向相反。
  10. 根据权利要求1至9任一项所述的平面变压器，其特征在于，所述n个第一磁芯柱设置在预设区域内，所述k个第二磁芯柱分布在所述预设区域外。
  11. 一种电路板，其特征在于，所述电路板包括如权利要求1至10任一项所述的平面变压器。
  12. 一种电子设备，其特征在于，所述电子设备包括如权利要求1至10任一项所述的平面变压器。
PCT/CN2021/087201 2021-04-14 2021-04-14 平面变压器及相关设备 WO2022217494A1 (zh)

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