EP0716435A1 - Transformator mit gedruckten spulen - Google Patents

Transformator mit gedruckten spulen Download PDF

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Publication number
EP0716435A1
EP0716435A1 EP95921971A EP95921971A EP0716435A1 EP 0716435 A1 EP0716435 A1 EP 0716435A1 EP 95921971 A EP95921971 A EP 95921971A EP 95921971 A EP95921971 A EP 95921971A EP 0716435 A1 EP0716435 A1 EP 0716435A1
Authority
EP
European Patent Office
Prior art keywords
core
feet
mid
sectional area
loss
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP95921971A
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English (en)
French (fr)
Other versions
EP0716435A4 (de
Inventor
Kiyoharu Inou
Hisanaga Takano
Humiatu Takahashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yokogawa Electric Corp
Original Assignee
Yokogawa Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yokogawa Electric Corp filed Critical Yokogawa Electric Corp
Publication of EP0716435A1 publication Critical patent/EP0716435A1/de
Publication of EP0716435A4 publication Critical patent/EP0716435A4/de
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/04—Fixed inductances of the signal type  with magnetic core
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/0006—Printed inductances

Definitions

  • the present invention relates to a coil structure suitably used for transformers and choking coils used in electronic equipments and power units and more particularly to a device having an excellent magnetic coupling, a low loss and an excellent high frequency characteristic when used as a transformer.
  • a transformer is a magnetic part used in electronic equipments and power units and has a quality of insulating the primary side from the secondary side and of defining a secondary voltage in response to a primary voltage and a turn ratio.
  • coil transformers constructed by winding a lead wire around a bobbin have spread and the size of the magnetic core has been standardized by the standards of JIS and IEC, etc.
  • a printed coil type transformer in a plane type transformer in which a mid-leg core 33 of EE shaped cores or EI shaped cores is disposed through the center of a spiral of a coil laminate 40 in which a plurality of concentric spiral coils are laminated in a thickness direction by using an insulating resin to obtain a magnetic coupling between the plurality of coils is characterized in that: sectional areas of the core at a feet core 34 and a connecting core 35 are approximately the same; an sectional area (Ae) of the mid-leg core is approximately twice of that of the feet core; the sectional area satisfies the following expression in connection with a core volume (Ve): 1.4 ⁇ Ve 1/3 /Ae 1/2 ⁇ 1.7; and the following expression is satisfied between a space(w) between the mid-leg core and the feet core of the core and a height (h) of the mid-leg core: 0.5 ⁇ h/w ⁇ 2.
  • the sectional area of the core is unified along the magnetic path to keep the magnetic flux density almost constant, no loss will increase locally.
  • the section of the coil is surrounded by a window section formed by the mid-leg core and the feet cores of the core, the coil resistance can be minimized by optimizing the shape of the core, thus contributing to the miniaturization of the transformer.
  • FIG. 1 is a structural perspective view of an assembling state, in which a part of a coil laminate is cut away, showing one preferred embodiment of the present invention.
  • a coil laminate 40 is what a conventional bobbin and a lead wire are put together in one body and a concrete detailed structure thereof has been disclosed in Japanese Patent Laid-Open No. Hei. 6-310345 for example which the present applicant has proposed.
  • a core hole 41 is created at the center of the coil laminate 40 and a mid-leg core of an upper core 31 and a lower core 32 are inserted thereto.
  • Terminals 42 are embedded in two sides crossing with other sides where feet cores 34 of the upper core 31 and the lower core 32 are attached.
  • FIG. 2 is a section view of the coil laminate 40, showing a section along a direction of 2-2 in FIG. 1.
  • two layers of secondary coils 45 exist in the middle while being sandwiched by respective upper and lower layers of primary coils 44.
  • An internal interconnecting terminal 43a for interconnecting the respective upper and lower layers of the primary coil 44 and an internal interconnecting terminal 43b for interconnecting all of the primary coils 44 and the secondary coils 45 are provided near the core hole 41.
  • Terminals 42 are provided at the both ends of the coil laminate 40.
  • One terminal is a primary terminal 42a for interconnecting the respective upper and lower layers of the primary coils 44 and the other terminal is a secondary terminal 42b for interconnecting the two layers of the secondary coils 45.
  • each layer of the primary coil 44 is would by three turns of coil and each layer of the secondary coil 45 is wound by two turns of coil. Because the gaps between each layer of the coil are filled with an insulating resin and an isolating distance required in obtaining various safety standards is so thin as 0.6 mm, the transformer can be miniaturized further.
  • FIGs. 3A through 3C are drawings for explaining the detail of the shape of a core 30, wherein FIG. 3A is a front view when the upper core 31 and the lower core 32 are assembled, FIG. 3B is a plan view of the core, and FIG. 3C is a perspective view for explaining sectional areas of the core.
  • a length of the connecting core 35 is represented by A
  • a space between the inner sides of the feet core 34 is represented by E and a thickness of the feet core 34 is represented by b.
  • a space between the inner side of the feet core 34 and a peripheral face of the mid-leg core 33 facing thereto is represented by w.
  • H a height of the connecting core 35 when the upper core 31 and the lower core 32 has been assembled
  • h a space between the inner faces of the connecting core 35 facing to each other
  • t a thickness of the connecting core 35
  • a sectional area Ae 35 of the connecting core 35, a sectional area Ae 34 of the feet core 34 and a sectional area Ae 33 of the mid-leg core 33 in the magnetic flux direction are defined to a value almost equal with respect to a sectional area per one line of magnetic flux passing through the connecting core 35 ⁇ the feet core 34 ⁇ the mid-leg core 33 to prevent the flux density from locally increasing and thus increasing the loss. Because two lines of magnetic flux pass through the mid-leg core 33, the sectional area Ae 33 is two times of the sectional area of other cores Ae 35 and Ae 34.
  • the iron loss refers to an electric power consumed in the magnetic iron core due to a time-varying magnetizing force and includes a hysteresis loss and an eddy current loss.
  • the copper loss is a load loss and includes an I2R loss caused by the eddy current and load in the coil, a stray loss caused by a leakage current and a loss caused by circulating currents in parallel coils.
  • FIG. 4 is a conceptual graph for explaining a relationship between a transformer loss Ploss and a core sectional area Ae.
  • the transformer loss is defined by a sum of the iron loss PFe and the copper loss PCu of the coil.
  • the iron loss PFe is apt to increase along the increase of the core sectional area Ae.
  • the copper loss PCu is apt to decrease along the increase of the core sectional area Ae. Accordingly, there exists an optimum core sectional area Ae which minimizes the loss in the transformer loss Ploss represented by the sum of the both.
  • the transformer loss may be minimized when the expression (12) is minimized.
  • the transformer loss may be minimized when the expression (15) is minimized.
  • FIGs. 5A and 5B are structural perspective views showing a second embodiment of the present invention, wherein FIG. 5A shows a state in which UU shaped cores are mounted to a coil laminate and FIG. 5B shows a simplex of the coil laminate.
  • the U shaped core has a connecting core 37 and two feet cores 36 provided on the both sides thereof.
  • the two-holed coil laminate 50 has two core holes 51a and 51b and the detailed structure thereof has been disclosed in Japanese Patent Laid-Open No. Hei. 6-333759 for example which the present applicant has proposed. Rows of terminals 52 are provided respectively at the edge of the both sides along the direction in which the core of the two-holed coil laminate 50 is mounted.
  • the UU shaped cores or UI shaped cores are mounted to the two-holed coil laminate 50 to create a closed magnetic path.
  • FIGs. 6A and 6B are structural diagrams for explaining the shape of the UU shaped cores, wherein FIG. 6A is a front view in a state when the UU shaped cores have been assembled and FIG. 6B is a plan view of the U shaped core. Although the same reference numerals with those in FIG. 3 are used in FIG. 6 for the convenience of the explanation, they have values intrinsic in FIG. 6.
  • a diameter of the feet core 36 is represented by D.
  • a length of the connecting core 37 is represented by A, a thickness thereof t, a width thereof C and a space between inner peripheral faces of the feet cores 36 as 2w.
  • the transformer loss may be minimized when the expression (24) is minimized.
  • FIGs. 7A and 7B are structural diagrams in which the ratio of dimensions of the core window (h/w) is 1 and which provide the standard in comparing with embodiments in FIGs. 8 and 9, wherein FIG.
  • FIG. 7A is a plan view in a state when EE shaped cores are mounted to a coil laminate and FIG. 7B is a section view along B-B line in FIG. 7A and substantially shows a state in which the device shown in FIG. 1 has been assembled.
  • FIGs. 8A and 8B are structural views showing a third embodiment of the present invention in which the ratio of dimensions of the core window (h/w) is 1/2, wherein FIG. 8A is a plan view when EE cores are mounted to a coil laminate and FIG. 8B is a section view along B-B line in FIG. 8A.
  • the section of the coil laminate 40 can be flat and the conductor as well. Then, because the copper loss decreases from the quality that the larger the conductor surface area, the smaller an AC resistance related to the copper loss can be from the skin effect, the increase of the transformer loss is actually less than 5 %.
  • FIGs. 9A and 9B are structural views showing a fourth embodiment of the present invention in which the ratio of dimensions of the core window (h/w) is 2, wherein FIG. 9A is a plan view when EE cores are mounted to a coil laminate and FIG. 9B is a section view along B-B line in FIG. 9A.
  • the section of the coil laminate 40 can be made vertically long.
  • the plan dimension of the coil laminate 40 can be reduced and the transformer mounting area can be reduced.
  • the transformer mounting area of the case in FIG. 9 in which the core window is vertically long can be 1/2 of the case in FIG. 7 in which the lengths are equal. Then, it is suitable for the use in which a small transformer mounting area is a merit like the field in which a high density mounting is required.
  • the shape of the transformer which minimizes the transformer loss when the ratio of the dimensions of the core window (h/w) is within the range of 1/2 through 2 may be realized when the coefficient k is within the following range as described in connection with the expressions (18),(27), (28) and (29): 1.4 ⁇ k ⁇ 1.7 (1.2 ⁇ h/w ⁇ 2)
  • a height H of the EE shaped core is lower and a length A is also shorter by about 10 % in the present invention.
  • a core volume Ve thereof is smaller by about 20 % and a core sectional area Ae is larger by about 30 % in contrary. Because an amount of magnetic material used may be small if the core volume Ve is small, a light weight transformer can be manufactured at low cost. While the ratio of dimensions of the core window is flat as h/w ⁇ 1/2 in the conventional transformer, it is vertically long as h/w ⁇ 1.5 in the present invention. Then, it can be seen that the performance of the present invention as a transformer is better because the copper loss is reduced by 40 % and the iron loss is reduced by 18 % in terms of the transformer loss.
  • FIG. 10A and 10B are structural perspective views showing a fifth embodiment of the present invention, wherein FIG. 10A shows a state in which EE shaped cores are mounted to a coil laminate and FIG. 10B shows a simplex of the coil laminate.
  • FIGs. 11A and 11B are diagrams for explaining the shape of the EE shaped cores, wherein FIG. 11A is a front view when the EE shaped cores are assembled and FIG. 11B is a plan view of the E shaped core.
  • This fifth embodiment is a variation of the embodiment shown in FIG. 3. While the diameter D of the mid-leg core 33 and the width C of the connecting core 35 have been equal in the case of the embodiment shown in FIG. 3, it is selected to be D ⁇ C in the present embodiment.
  • a thickness b of the feet core can be thinned and dimensions of the core window h and w can be large, so that a core window area hw can be increased. As a result, it brings about an effect that the transformer can be miniaturized and thinned further.
  • FIGs. 12A through 12C are structural perspective views showing a sixth embodiment of the present invention, wherein FIG. 12A shows a state in which EI shaped cores are mounted to the coil laminate, FIG. 12B shows the simplex of the coil laminate and FIG. 12C is a drawing for explaining a state in which the EI shaped cores are assembled.
  • This sixth embodiment is a variation of the embodiment shown in FIG. 3, in which the EE shaped cores of the core 30 are replaced with the EI shaped cores.
  • the same effect with the first embodiment can be obtained even by adopting such shape by having substantially the same core window dimensions h and w.
  • the one-holed coil laminate 40 and the two-holed coil laminate 50 and the cores mounted thereto are selected respectively from the EE shaped and UU shaped cores, so that the ratio of dimensions of the core window and the coefficient k are defined in accordance to the expression (30).

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Coils Of Transformers For General Uses (AREA)
EP95921971A 1994-06-29 1995-06-15 Transformator mit gedruckten spulen Ceased EP0716435A4 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP14770294 1994-06-29
JP147702/94 1994-06-29
PCT/JP1995/001195 WO1996000972A1 (fr) 1994-06-29 1995-06-15 Transformateur a bobines imprimees

Publications (2)

Publication Number Publication Date
EP0716435A1 true EP0716435A1 (de) 1996-06-12
EP0716435A4 EP0716435A4 (de) 1996-11-20

Family

ID=15436322

Family Applications (1)

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EP95921971A Ceased EP0716435A4 (de) 1994-06-29 1995-06-15 Transformator mit gedruckten spulen

Country Status (3)

Country Link
EP (1) EP0716435A4 (de)
TW (1) TW436823B (de)
WO (1) WO1996000972A1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2328801A (en) * 1997-08-25 1999-03-03 Kwangju Electronics Co Limited An inductor for attenuating harmonic current of a motor arrangement
CN101090029B (zh) * 2006-06-12 2010-05-12 台达电子工业股份有限公司 变压器
CN105374492A (zh) * 2015-12-23 2016-03-02 厦门新页科技有限公司 一种用于大气隙磁路的磁芯
CN105895326A (zh) * 2016-06-29 2016-08-24 南通华兴磁性材料有限公司 开关电源变压器磁芯

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11354315A (ja) * 1998-06-03 1999-12-24 Hitachi Metals Ltd 薄型フェライトコア
JP4472589B2 (ja) * 2005-06-28 2010-06-02 スミダコーポレーション株式会社 磁性素子
JP2009059954A (ja) * 2007-08-31 2009-03-19 Hitachi Powdered Metals Co Ltd ディスク型リアクトル
JP5247385B2 (ja) * 2008-12-01 2013-07-24 株式会社デンソー リアクトル
FR3045921B1 (fr) * 2015-12-17 2019-07-12 Commissariat A L'energie Atomique Et Aux Energies Alternatives Circuit a inductance integrant une fonction de gestion thermique passive

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2059166A (en) * 1979-05-24 1981-04-15 Kijima Musen Kk Transformer for a blocking oscillator
GB2087656A (en) * 1980-11-14 1982-05-26 Analog Devices Inc Miniaturized transformer construction
EP0068745A1 (de) * 1981-06-19 1983-01-05 TDK Corporation Ferritkern und Vorrichtungen, die solche Kerne aufweisen
EP0245083A1 (de) * 1986-05-07 1987-11-11 TDK Corporation Ferritkern und Transformator oder Induktor mit solchem Kern
EP0267822A1 (de) * 1986-10-15 1988-05-18 Electronique Serge Dassault Hochfrequenztransformator mit gedruckter Schaltungswicklung, insbesondere für sehr hohe Spannungsquelle

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6025123U (ja) * 1983-07-26 1985-02-20 日本フェライト株式会社 フェライト磁心
EP0267108A1 (de) * 1986-10-31 1988-05-11 Digital Equipment Corporation Miniaturisierter Transformator
JPS63157913U (de) * 1987-04-06 1988-10-17
FR2615319B1 (fr) * 1987-05-15 1989-07-07 Bull Sa Transformateur a fort couplage adapte a un circuit d'alimentation a decoupage et circuit d'alimentation a decoupage comportant un tel transformateur
JP2850144B2 (ja) * 1989-12-21 1999-01-27 ティーディーケイ株式会社 フェライトコア
JPH06333759A (ja) * 1993-05-24 1994-12-02 Yokogawa Electric Corp プリントコイル形トランス

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2059166A (en) * 1979-05-24 1981-04-15 Kijima Musen Kk Transformer for a blocking oscillator
GB2087656A (en) * 1980-11-14 1982-05-26 Analog Devices Inc Miniaturized transformer construction
EP0068745A1 (de) * 1981-06-19 1983-01-05 TDK Corporation Ferritkern und Vorrichtungen, die solche Kerne aufweisen
EP0245083A1 (de) * 1986-05-07 1987-11-11 TDK Corporation Ferritkern und Transformator oder Induktor mit solchem Kern
EP0267822A1 (de) * 1986-10-15 1988-05-18 Electronique Serge Dassault Hochfrequenztransformator mit gedruckter Schaltungswicklung, insbesondere für sehr hohe Spannungsquelle

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
JOURNAL OF MICROMECHANICS AND MICROENGINEERING, vol. 3, no. 2, June 1993, ATLANTA,USA, pages 37-44, XP002014204 CHONG H AHN: "A planar micromachined spiral inductor for integrated magnetic microactuator applications" *
MULLARD TECHNICAL COMMUNICATIONS, JAN. 1975, UK, vol. 13, no. 125, ISSN 0027-3139, pages 225-228, XP002014291 "FX3700 series transformer cores and coil formers for SMPS" *
ONDE ELECTRIQUE, vol. 59, no. 12, December 1979, PARIS FR, pages 71-80, XP002014203 R. SIBILLE: "Noyaux en ferrites pour alimentation a découpage" *
See also references of WO9600972A1 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2328801A (en) * 1997-08-25 1999-03-03 Kwangju Electronics Co Limited An inductor for attenuating harmonic current of a motor arrangement
GB2328801B (en) * 1997-08-25 2000-03-08 Kwangju Electronics Co Limited Harmonic current attenuating device of a motor
CN101090029B (zh) * 2006-06-12 2010-05-12 台达电子工业股份有限公司 变压器
CN105374492A (zh) * 2015-12-23 2016-03-02 厦门新页科技有限公司 一种用于大气隙磁路的磁芯
CN105374492B (zh) * 2015-12-23 2018-02-13 厦门新页科技有限公司 一种用于大气隙磁路的磁芯
CN105895326A (zh) * 2016-06-29 2016-08-24 南通华兴磁性材料有限公司 开关电源变压器磁芯

Also Published As

Publication number Publication date
TW436823B (en) 2001-05-28
EP0716435A4 (de) 1996-11-20
WO1996000972A1 (fr) 1996-01-11

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