EP0377691A1 - Transformateur matriciel a isolation dielectrique elevee - Google Patents

Transformateur matriciel a isolation dielectrique elevee

Info

Publication number
EP0377691A1
EP0377691A1 EP89905315A EP89905315A EP0377691A1 EP 0377691 A1 EP0377691 A1 EP 0377691A1 EP 89905315 A EP89905315 A EP 89905315A EP 89905315 A EP89905315 A EP 89905315A EP 0377691 A1 EP0377691 A1 EP 0377691A1
Authority
EP
European Patent Office
Prior art keywords
primary
matrix transformer
transformer
matrix
winding
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Withdrawn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
EP89905315A
Other languages
German (de)
English (en)
Other versions
EP0377691A4 (en
Inventor
Edward Herbert
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.)
FMTT Inc
Original Assignee
FMTT Inc
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 FMTT Inc filed Critical FMTT Inc
Publication of EP0377691A1 publication Critical patent/EP0377691A1/fr
Publication of EP0377691A4 publication Critical patent/EP0377691A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • H01F17/06—Fixed inductances of the signal type  with magnetic core with core substantially closed in itself, e.g. toroid
    • 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
    • H01F2038/006—Adaptations of transformers or inductances for specific applications or functions matrix transformer consisting of several interconnected individual transformers working as a whole
    • 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
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase ac
    • H01F38/28—Current transformers
    • H01F38/30—Constructions
    • H01F2038/305—Constructions with toroidal magnetic core

Definitions

  • This invention relates to transformers, and in particular to transformers which have a requirement for high dielectric isolation, such as safety transformers.
  • a matrix transformer comprises a plurality of interdependant magnetic elements, interwired as a transformer, as taught by U. S. Patent 4,665,357, "Plat Matrix Transformer", Herbert, May 12, 1987. Because of the small size of the interdependant magnetic elements, and the close proximity and intermingling of its windings, it is not apparent that the flat matrix transformer could have much dielectric isolating capability.
  • Figure 1 shows a matrix transformer having high dielectric insulation.
  • Figure 2 shows the transformer of figure 1, without the wiring, to more clearly show the insulating system.
  • Figure 3 shows a section through one of the magnetic elements of figure 1.
  • Pigure 4 shows a section through one magnetic element of a matrix transformer similar to the transformer of figure 1, but incorporating a safety shield.
  • Figure 5 shows a matrix transformer having an intermediate, low voltage winding to further isolate the secondary circuit from the primary circuit.
  • Figure 6 shows the a transformer similar to the one of figure 5, without the primary and secondary windings to more clearly show the intermediate low voltage winding. The ends of the low voltage intermediate winding are shown grounded.
  • the matrix transformer is made of many magnetic elements, which are arranged and interwired to behave collectively as a transformer.
  • the art of designing and manufacturing matrix transformers is adaptable to a very wide variety of shapes, sizes and configurations.
  • Transformers belong to a broad family of static devices in which electric currents in conductors interact by means of magnetic induction with changing fluxes in magnetic cores. These include potential transformers, current transformers, flyback transformers, induction coils, “constant current output” transformers, multiple winding inductors and inductors. "Matrix transformer” is used herein as a generic term including any of these devices when they are built using an array of smaller interdependent magnetic elements interwired as a whole.
  • the matrix transformer designed in this way functions as an ordinary transformer, but because of the manner in which the various elemental parts cooperate interdependently, it has some unique characteristics which can be used to advantage in many applications. Matrix transformers can also be designed which have characteristics which no single core device could have.
  • the magnetic elements can be small cores of ordinary design, such as C cores, E-I cores, pot cores or toroids, but alternatively can be one of several new geometries having multiple magnetic return paths such as two parallel plates bridged by a multitude of posts, a plurality of modified cross cores, or a plate of magnetic material having a plurality of holes therein.
  • Different types of interdependent magnetic elements can be inter ⁇ mixed in an interdependent matrix array as long as the rules of transformers are followed.
  • the matrix transformer can be very flat, and the electrical circuits can be made using printed wiring board techniques.
  • matrix transformers There is a high degree of flexibility and discretion in the design of matrix transformers, including, but not limited to, the number of magnetic elements, the detailed design of the elements, and the physical arrangements of the elements. Also, the windings of the matrix transformer can be arranged in different ways, and there is flexibility in choosing how and where a particular winding enters and exits the transformer. The voltages and the currents in the matrix transformer have a definite relationship, one to another, and this information can be exploited to optimize the design.
  • Pigure 1 shows a matrix transformer which has been built incorporating several features for high dielectric isolation. Typical requirements for high dielectric isolation will include a creep distance for the primary, a creep distance for the secondary, a creep distance between the primary and the secondary, a required number of layers of insulation, a distance through the insulation, and a dielectric test requirement.
  • the transformer. of figure 1 comprises ten interdependant magnetic elements, shown a toroids 101a, - j.
  • a primary winding 102 shown as a push pull (centertapped) winding, five parallel secondary windings 103a,b, (etc. ) , also shown as push pull (centertapped) windings.
  • Primary insulation 105a,b encloses the primary winding 102, and extends entirely through the matrix transformer, uninterrupted, and extends beyond it on both ends. The amount that it extends on each end is determined by the creepage distance requirements to the secondary.
  • Secondary insulation 104a,b-j encloses the secondary winding where it passes through the magnetic elements, and extends beyond each magnetic element on each side. The amount that it extends is determined by the creepage distance of the secondary to the core.
  • the primary and secondary insulation can be insulating tubing, such as Teflon.
  • Figure 2 shows the transformer of figure 1 without the primary and secondary wires.
  • Primary insulation 205a,b could be one continuous piece of insulation, and would not have to extend beyond the transformer on the closed end. This would be preferred if it were important to minimize primary leakage inductance.
  • the path of the primary winding is quite serpentine. For this, a flexible insulation would be preferred, and it would probably be easier to pull the primary wires through the insulation prior to installing it in the matrix transformer.
  • Figure 3 shows a section through one of the magnetic elements of the transformer of figure 1. All of the are similar.
  • 301 is the magnetic element, illustrated as a toroid, though it could be any type of magnetic core such as a U-I core, one side of an E core, a pot core or a specialized core structure for matrix transformers.
  • the primary winding 302 preferably comprises a winding of insulated wire (preferably not just a film or varnish insulation) such as ordinary Teflon type E hook up wire.
  • the secondary winding 303 is similar to the primary, and can be the same gauge, the currents being equal to the primary as is the nature of matrix transformers. In some applications or embodiments of the invention the secondary might not require the same amount of insulation Secondary and primary insulation 305 and 305 enclose each winding.
  • the dielectric isolation criteria are fulfilled as follows: The primary creepage distance to the core and to the secondary is satisfied by the amount that the primary insulation 104 extends beyond the ends of the matrix transformer. The secondary creepage distance to the core is satisfied by the amount that the secondary insulation 105 extends beyond each magnetic element 101.
  • the spacing through the insulation for the primary winding to the core is satisfied by the combined thickness of the insulation of the primary winding wire 102 and the primary insulation 104.
  • the spacing through the insulation for the secondary winding to the core is satisfied by the combined thickness of the insulation of the secondary winding wire 103 and the secondary insulation 105.
  • the spacing through the insulation from primary to secondary is satisfied by the thickness of the wire insulation of both windings and the thickness of both the primary and the secondary insulations.
  • the insulation system would be preferred for various applications. If either the primary or the secondary, or both, were a single wire winding, the use of a wire having sufficient insulation of itself would be consistent with the teachings of this invention. Such an insulation would probably have at least two layers, and its total insulation thickness would be greater than " the specification requirements. In some cases this would be preferred even with windings having more than one wire, particularly if the primary wires followed different paths through the transformer, or if it were interrupted, as for switching elements or other components or the like.
  • a second layer of insulation around the primary or the secondary or both might be used. This might be the case where there were more than one wire in a winding, and the winding factor could be improved by using a wire with insufficient insulation to meet the minimum requirements as a layer.
  • Some magnetic materials are very good insulators, such as nickel ferrites.
  • some magnetic cores are encapsulated or otherwise insulated. In either case, the insulation system, particularly the secondary, might be reduced, or even eliminated, and still provide sufficient dielectric isolation.
  • the primary insulations system might be upgraded.
  • a matrix transformer similar to the one in figure 1 can be made with ferrite cores such as Pair-rite (tm) part no. 2677006301, which are about 3/8" outside diameter.
  • the primary and secondary windings can be made with awg 22 Teflon hook up wire. If the primary and secondary windings are each inside a number 12 Teflon sleeving, the transformer will meet very high dielectric isolation requirements. (In test, there was no dielectric failure to the limit of the available test equipment: 40,000 VDC) .
  • a transformer similar to the transformer of figure 1 was installed in a bread board of a push-pull pulse width modulated switch mode power supply.
  • the input voltage was 40 to 60 volts, with 5 volts out.
  • the primary was driven with a Unitrode (tm) part no. 3825 integrated circuit, buffered to improve the output fall time.
  • the primary switches were n-channel power MOSFET's (metal- oxide-silicon field effect transistors).
  • the individual secondaries were rectified with dual Schottky rectifiers.
  • the individual secondary centertaps were connected to ground through small inductors.
  • the anodes of each pair of rectifiers were connected together and to small ceramic capacitors, which was returned to ground, the whole being kept very tight. The outputs were then paralleled.
  • Figure 4 shows a section of a magnetic element of a transformer similar to the transformer of figure 1, except that a safety shield 406 has been added. All other features are the same as the corresponding features of figure 3.
  • the safety shield would preferably be terminated to a ground plane (which could also be a heat sink) immediately when it left the core.
  • the shield could more fully, or completely enclose the primary or the secondary, or both, (but preferably not both together in one shield) .
  • Figure 5 teaches an embodiment of the matrix transformer having an intermediate low voltage winding to further isolate the primary from the secondary.
  • a primary winding 502 couples a first set of ten interdependant magnetic elements 501k-u.
  • a primary insulator 503a,b extends through the transformer. Pairs of magnetic elements 501k-u couple a pairs of a second set-of magnetic elements 501a-j through intermediate low voltage windings 506a-e.
  • the second set of magnetic elements 501a-j can have any suitable matrix transformer secondary, shown here as five parallel secondaries 503a-e.
  • Figure 6 shows the intermediate low voltage windings more clearly, and shows that they are preferably grounded to a ground plane at both ends. In this manner, it can be seen that no dielectric failure will allow primary voltage to appear on the secondary as long as the ground plane can carry fault currents away.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Insulating Of Coils (AREA)

Abstract

On a mis au point un transformateur matriciel à isolation diélectrique élevée, ayant la capacité de supporter des potentiels très élevés entre son primaire (102) et son secondaire (103a, b), et bien adapté pour une utilisation comme transformateur sans danger dans des alimentations en mode de commutation. On peut également séparer physiquement le primaire et le secondaire l'un de l'autre à l'aide d'un enroulement intermédiaire (606), lequel se trouve au potentiel de terre.
EP19890905315 1988-04-28 1989-04-21 Matrix transformer having high dielectric isolation Withdrawn EP0377691A4 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US18725388A 1988-04-28 1988-04-28
US187253 1988-04-28

Publications (2)

Publication Number Publication Date
EP0377691A1 true EP0377691A1 (fr) 1990-07-18
EP0377691A4 EP0377691A4 (en) 1990-10-10

Family

ID=22688219

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890905315 Withdrawn EP0377691A4 (en) 1988-04-28 1989-04-21 Matrix transformer having high dielectric isolation

Country Status (6)

Country Link
EP (1) EP0377691A4 (fr)
JP (1) JPH03500948A (fr)
KR (1) KR900701021A (fr)
AU (1) AU3537589A (fr)
BR (1) BR8906934A (fr)
WO (1) WO1989010621A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2307795A (en) * 1995-12-01 1997-06-04 Metron Designs Ltd Isolation transformer with plural magnetic circuits coupled by a winding
DE29716058U1 (de) * 1997-09-06 1997-10-23 Wollnitzke, Helmut, 95100 Selb Magnetisierbares elektrisches Bauelement
DE10218455A1 (de) * 2002-04-25 2003-11-06 Abb Patent Gmbh Sperrwandleranordnung
JP2004335885A (ja) 2003-05-09 2004-11-25 Canon Inc 電子部品およびその製造方法
JP2004335886A (ja) * 2003-05-09 2004-11-25 Canon Inc トランス集合体、それを用いた電力変換装置及び太陽光発電装置
WO2016036420A1 (fr) 2014-09-05 2016-03-10 PICHKUR, Dmytro Transformateur

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA474473A (fr) * 1951-06-12 C. Wentz Edward Isolateurs de conducteurs a haute tension
US2600057A (en) * 1949-05-18 1952-06-10 Quentin A Kerns High-voltage multiple core transformer
NL229257A (fr) * 1957-07-24
US2945961A (en) * 1958-05-05 1960-07-19 Ite Circuit Breaker Ltd Current balancing reactors for diodes
US3577110A (en) * 1969-05-09 1971-05-04 Dominion Electric Corp Transformer having a wound core around linear conductors
US3725741A (en) * 1971-06-30 1973-04-03 Westinghouse Electric Corp Differential transformer mounting arrangement particulary for ground fault interrupter apparatus
US3961292A (en) * 1974-01-02 1976-06-01 Ross Alan Davis Radio frequency transformer
US3996513A (en) * 1975-04-24 1976-12-07 Butler Fred C Differential microampere current sensor
US4021729A (en) * 1975-12-03 1977-05-03 I-T-E Imperial Corporation Cross-field ground fault sensor
US4414543A (en) * 1980-09-25 1983-11-08 Schweitzer Edmund O Jun Ground fault indicator
US4510478A (en) * 1981-08-17 1985-04-09 Mid-West Transformer Company Coil body
US4617543A (en) * 1984-01-26 1986-10-14 Tdk Corporation Coil bobbin

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
No relevant documents have been disclosed. *
See also references of WO8910621A1 *

Also Published As

Publication number Publication date
KR900701021A (ko) 1990-08-17
AU3537589A (en) 1989-11-24
EP0377691A4 (en) 1990-10-10
BR8906934A (pt) 1990-09-11
WO1989010621A1 (fr) 1989-11-02
JPH03500948A (ja) 1991-02-28

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