EP0484074A2 - Transformateur à haute fréquence avec réactance à champ de dispersion fort - Google Patents

Transformateur à haute fréquence avec réactance à champ de dispersion fort Download PDF

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Publication number
EP0484074A2
EP0484074A2 EP91309923A EP91309923A EP0484074A2 EP 0484074 A2 EP0484074 A2 EP 0484074A2 EP 91309923 A EP91309923 A EP 91309923A EP 91309923 A EP91309923 A EP 91309923A EP 0484074 A2 EP0484074 A2 EP 0484074A2
Authority
EP
European Patent Office
Prior art keywords
permeability
housing
winding
transformer
low
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.)
Withdrawn
Application number
EP91309923A
Other languages
German (de)
English (en)
Other versions
EP0484074A3 (en
Inventor
Robert Philbrick Alley
Robert Louis Steigerwald
Sayed-Amr Ahmes El-Hamamsy
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.)
General Electric Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Publication of EP0484074A2 publication Critical patent/EP0484074A2/fr
Publication of EP0484074A3 publication Critical patent/EP0484074A3/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/08—High-leakage transformers or inductances
    • H01F38/10—Ballasts, e.g. for discharge lamps
    • 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
    • H01F2027/348—Preventing eddy currents

Definitions

  • the present invention relates generally to magnetic circuit components. More particularly, the present invention relates to a high-frequency transformer having a high, controllable leakage reactance.
  • a conventional core also has a winding window for containing conductors encased by an insulating material.
  • the air gaps in a core of sufficiently small volume are so large relative to the overall window size that the fringing field flux penetrates the conductors. Such field nonuniformity generates excessive eddy current losses.
  • the ac resistance is significantly larger than the dc resistance.
  • the low-permeability core forms a closed-loop structure surrounding the winding window which contains planar copper conductors encased by an insulating material.
  • a low-permeability core structure will result in reduced ac winding losses, losses will still be caused by the uneven distribution of current in the conductors resulting from field nonuniformity. Specifically, regions of high field intensity will result from the crowding of flux lines around corners of the core structure as they follow the paths of least reluctance. This high field intensity will produce undesirable eddy current circulation in the outermost conductors of the winding.
  • a dual-permeability core structure for use in high-frequency magnetic components which exhibits low winding losses and a low ac-to-dc resistance ratio.
  • the dual-permeability core encloses a winding window containing planar windings and comprises high-permeability and low-permeability sections positioned to produce a highly uniform, or uniformly varying, magnetic field on the winding surfaces.
  • a magnetic structure as described in the Ngo and Charles patent is useful for constructing high-efficiency inductors and transformers.
  • a resonant power supply typically employs a resonant circuit, including an inductor, and an isolation transformer.
  • a discharge lamp ballast such as for a fluorescent lamp. It would be desirable, therefore, to construct a high-frequency, high-leakage-reactance transformer employing planar windings which could function as both the inductor and isolation transformer, thereby decreasing the size and increasing the efficiency of the circuit.
  • an object of the present invention is to provide a high-frequency, high-leakage-reactance transformer employing planar windings which exhibits low winding losses.
  • Another object of the present invention is to provide a high-frequency transformer employing planar windings and having a controlled leakage reactance so that it can function as both a transformer and an inductor, thereby decreasing the number of components and size of the circuit in which the transformer is employed.
  • a new and improved high-frequency, high-leakage-reactance transformer employing a section of low-permeability material between planar primary and secondary windings.
  • the low-permeability section provides a controlled flux path for the leakage flux between the primary and secondary windings.
  • excessive eddy currents are prevented from flowing in the planar windings, and the electrostatic coupling between the primary and secondary windings is substantially reduced.
  • High-efficiency operation is thus obtained.
  • the high-leakage-reactance transformer functions both as a transformer, e.g. for isolation, and an inductor.
  • Such a combination structure advantageously reduces the number of components and size of the circuit.
  • Figures 1 and 2 are, respectively, axial symmetric flux line plots derived by computer simulation for an E-shaped, lumped gap magnetic core 10 and a core 12 employing a low-permeability section 14 in accordance with the present invention.
  • Each core 10 and 12 is shown as having a planar conductor 16, representing a transformer primary winding, carrying a current of 1 ampere passing through the portion of the core representing the winding window 18.
  • the planar conductors 16 are wound around the respective axes of symmetry, i.e. center legs 17, of the respective cores.
  • each core 10 and 12 has the same inductance. Specifically, for approximately 579 ⁇ J of excitation energy, the inductance of each core 10 and 12 is about 0.1158 ⁇ H. From the flux plots, it is clear that the stray flux in the region of the winding window of core 12 is significantly lower than that of core 10. Since eddy currents are approximately proportional to the square of the stray flux, the eddy current losses for core 12 would be significantly less than those of core 10. For the specific example of Figures 1 and 2, the eddy current losses for core 12 would be less than about 36% of those of core 10.
  • FIG 3 illustrates one preferred embodiment of a high-frequency, high-leakage-reactance transformer 20 in accordance with the present invention.
  • the transformer of Figure 1 has a pot core structure, including a cylindrical housing 22 and a core post 24 that extends between the opposite ends of the housing and is concentric therewith.
  • the cylindrical housing and the core post are each comprised of a high-permeability material.
  • In the interior of the housing there is a cylindrical winding window 26 that contains a primary winding 28 and a secondary winding 10 wound about the core post.
  • the primary and secondary windings are each preferably comprised of planar or foil conductors.
  • the primary and secondary windings are separated by a low-permeability section 32 comprising a cylindrical inner wall concentric to the cylindrical peripheral wall of housing 22.
  • the low-permeability section provides a controlled flux path for the leakage flux between the primary and secondary windings.
  • electrostatic coupling between the primary and secondary windings is substantially reduced because of the high resistance of the transformer core material in addition to the physical separation of the windings. High-efficiency operation is thus obtained.
  • the high-leakage-reactance transformer can function both as a transformer, e.g. for isolation, and an inductor. Such a combination structure advantageously reduces the number of components and size of the circuit.
  • a primary winding 34 and a secondary winding 36 each comprise a plurality of circular, planar conductors arranged in a stack along the longitudinal direction of the core.
  • Each winding includes a hole for receiving core post 24 during assembly.
  • Suitable windings are described in commonly assigned U.S. Pat. No. 4,959,630 of A.J. Yerman and K.D.T. Ngo, issued September 25, 1990, and in commonly assigned U.S. patent application of A.J. Yerman and K.D.T. Ngo, serial no. 359,063, filed May 30, 1989, which are incorporated by reference herein.
  • the stack of planar conductors comprising the primary winding and the stack of planar conductors comprising the secondary winding are separated by a low-permeability section 38 disposed within the winding window parallel to the opposite ends of cylindrical housing 22.
  • a suitable high-permeability material comprises a high-permeability ferrite exhibiting low losses at high frequencies, such as a sintered ferrite of suitable composition, e.g. a manganese-zinc ferrite.
  • a suitable low-permeability material may comprise, for example, a mixture of a ferrite powder and an organic binder or a sintered ferrite.
  • any suitable low- and high-permeability magnetic materials may be used. Exemplary high- and low-permeability magnetic materials are described in U.S. Pat. No. 4,943,793, cited hereinabove.
  • Another suitable low-permeability magnetic material is sold under the trademark KB6 by Krystinel Corporation. Methods for manufacturing dual-permeability magnetic structures are described in U.S. Pat. No. 4,943,793, cited hereinabove, and in the commonly assigned divisional patent application thereof, serial no.519,997.
  • FIGS 5a and 5b illustrate another preferred embodiment of a high-frequency, high-leakage-reactance transformer 40 in accordance with the present invention.
  • the transformer of Figure 5 has a rectangular housing 42 of high-permeability magnetic material.
  • An interior high-permeability section 44 divides a winding window into two portions.
  • a low-permeability section 48a and 48b, respectively, is located within each respective portion of the winding window, the low-permeability sections 48a and 48b being substantially parallel to the interior high-permeability section 44.
  • a planar primary winding 50 having terminals 51 and 52 is wound about the interior high-permeability section 44.
  • a planar secondary winding 54 having terminals 55 and 56 is then wound about the primary winding 50 with the low-permeability sections 48a and 48b separating the primary and secondary windings.
  • the positions of the primary and secondary windings may be reversed in the core.
  • FIG. 6 illustrates still another preferred embodiment of a high-frequency, high-leakage-reactance transformer 60 in accordance with the present invention.
  • Transformer 60 has a substantially rectangular housing 62 comprised of a high-permeability magnetic material.
  • a high-permeability section 64 is disposed within a winding window 66 so that it is substantially parallel to the top and bottom of housing 62.
  • a low-permeability section 68 perpendicular to the high-permeability section 64 is also disposed within winding window 66.
  • a primary winding 70 having terminals 71 and 72 and a secondary winding 74 having terminals 75 and 76 are respectively wound about high-permeability section 64 with the low-permeability section 68 disposed therebetween.
  • the advantages of the transformer of the present invention are obtainable at any operating frequency, i.e. at least in the broad range from 50 Hz to 30 MHz.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Coils Of Transformers For General Uses (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
EP19910309923 1990-10-29 1991-10-28 High-frequency, high-leakage-reactance transformer Withdrawn EP0484074A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US60454990A 1990-10-29 1990-10-29
US604549 1996-02-21

Publications (2)

Publication Number Publication Date
EP0484074A2 true EP0484074A2 (fr) 1992-05-06
EP0484074A3 EP0484074A3 (en) 1993-02-24

Family

ID=24420047

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910309923 Withdrawn EP0484074A3 (en) 1990-10-29 1991-10-28 High-frequency, high-leakage-reactance transformer

Country Status (3)

Country Link
EP (1) EP0484074A3 (fr)
JP (1) JPH04283909A (fr)
CA (1) CA2053648A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0515958A1 (fr) * 1991-05-27 1992-12-02 Hella KG Hueck & Co. Starter haute-tension pour amorcer et alimenter en courant alternatif des lampes à décharge haute-pression sur des véhicules
FR2838912A1 (fr) * 2002-04-19 2003-10-24 Tyco Electronics France Sas Transformateur d'impulsions pour lampe a decharge a haute intensite, procede pour sa fabrication et module de starter pour une telle lampe
EP1498914A1 (fr) * 2003-07-16 2005-01-19 Marvell World Trade Ltd. Inductance de puissance à saturation réduite de courant continu
EP1635619A3 (fr) * 2004-09-10 2006-05-24 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Transformateur, amorceur et lampe à décharge haute-pression contenant un tel transformateur
US7218197B2 (en) 2003-07-16 2007-05-15 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US7489219B2 (en) 2003-07-16 2009-02-10 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US7679347B2 (en) 2004-07-13 2010-03-16 Marvell World Trade Ltd. Closed-loop digital control system for a DC/DC converter
US7760525B2 (en) 2003-08-21 2010-07-20 Marvell World Trade Ltd. Voltage regulator
US7872454B2 (en) 2003-08-21 2011-01-18 Marvell World Trade Ltd. Digital low dropout regulator
US8324872B2 (en) 2004-03-26 2012-12-04 Marvell World Trade, Ltd. Voltage regulator with coupled inductors having high coefficient of coupling
FR2982068A1 (fr) * 2011-11-02 2013-05-03 Valeo Sys Controle Moteur Sas Dispositif electromagnetique et actionneur electromagnetique correspondant

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107025985B (zh) * 2017-03-23 2019-02-05 西北核技术研究所 带缓冲层的Tesla变压器磁芯及变压器和该磁芯制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4613841A (en) * 1983-11-30 1986-09-23 General Electric Company Integrated transformer and inductor
US4943793A (en) * 1988-12-27 1990-07-24 General Electric Company Dual-permeability core structure for use in high-frequency magnetic components

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58173999A (ja) * 1982-04-06 1983-10-12 Seiko Instr & Electronics Ltd 動電形スピ−カ用振動板の加工方法
JPS5936407A (ja) * 1982-08-24 1984-02-28 Nec Corp 半導体増幅器

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4613841A (en) * 1983-11-30 1986-09-23 General Electric Company Integrated transformer and inductor
US4943793A (en) * 1988-12-27 1990-07-24 General Electric Company Dual-permeability core structure for use in high-frequency magnetic components

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0515958A1 (fr) * 1991-05-27 1992-12-02 Hella KG Hueck & Co. Starter haute-tension pour amorcer et alimenter en courant alternatif des lampes à décharge haute-pression sur des véhicules
FR2838912A1 (fr) * 2002-04-19 2003-10-24 Tyco Electronics France Sas Transformateur d'impulsions pour lampe a decharge a haute intensite, procede pour sa fabrication et module de starter pour une telle lampe
US7987580B2 (en) 2003-07-16 2011-08-02 Marvell World Trade Ltd. Method of fabricating conductor crossover structure for power inductor
US7849586B2 (en) 2003-07-16 2010-12-14 Marvell World Trade Ltd. Method of making a power inductor with reduced DC current saturation
US8098123B2 (en) 2003-07-16 2012-01-17 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US7218197B2 (en) 2003-07-16 2007-05-15 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US7307502B2 (en) 2003-07-16 2007-12-11 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US7489219B2 (en) 2003-07-16 2009-02-10 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US8028401B2 (en) 2003-07-16 2011-10-04 Marvell World Trade Ltd. Method of fabricating a conducting crossover structure for a power inductor
EP1498914A1 (fr) * 2003-07-16 2005-01-19 Marvell World Trade Ltd. Inductance de puissance à saturation réduite de courant continu
US7882614B2 (en) 2003-07-16 2011-02-08 Marvell World Trade Ltd. Method for providing a power inductor
US7023313B2 (en) 2003-07-16 2006-04-04 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US7868725B2 (en) 2003-07-16 2011-01-11 Marvell World Trade Ltd. Power inductor with reduced DC current saturation
US7872454B2 (en) 2003-08-21 2011-01-18 Marvell World Trade Ltd. Digital low dropout regulator
US7760525B2 (en) 2003-08-21 2010-07-20 Marvell World Trade Ltd. Voltage regulator
US8299763B2 (en) 2003-08-21 2012-10-30 Marvell World Trade Ltd. Digital low dropout regulator
US8324872B2 (en) 2004-03-26 2012-12-04 Marvell World Trade, Ltd. Voltage regulator with coupled inductors having high coefficient of coupling
US7679347B2 (en) 2004-07-13 2010-03-16 Marvell World Trade Ltd. Closed-loop digital control system for a DC/DC converter
US8183846B2 (en) 2004-07-13 2012-05-22 Marvell World Trade Ltd. Method and apparatus for controlling a DC/DC converter
US7528693B2 (en) 2004-09-10 2009-05-05 Osram Gesellschaft Mit Beschraenkter Haftung Transformer and starting device having a transformer, and high pressure discharge lamp having a transformer
EP1635619A3 (fr) * 2004-09-10 2006-05-24 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Transformateur, amorceur et lampe à décharge haute-pression contenant un tel transformateur
FR2982068A1 (fr) * 2011-11-02 2013-05-03 Valeo Sys Controle Moteur Sas Dispositif electromagnetique et actionneur electromagnetique correspondant

Also Published As

Publication number Publication date
CA2053648A1 (fr) 1992-04-30
EP0484074A3 (en) 1993-02-24
JPH04283909A (ja) 1992-10-08

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