EP0421514A1 - Impulstransformator - Google Patents

Impulstransformator Download PDF

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Publication number
EP0421514A1
EP0421514A1 EP90202532A EP90202532A EP0421514A1 EP 0421514 A1 EP0421514 A1 EP 0421514A1 EP 90202532 A EP90202532 A EP 90202532A EP 90202532 A EP90202532 A EP 90202532A EP 0421514 A1 EP0421514 A1 EP 0421514A1
Authority
EP
European Patent Office
Prior art keywords
core
transformer
secondary winding
primary
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Withdrawn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
EP90202532A
Other languages
English (en)
French (fr)
Inventor
Antonius Fredericus Mattias Bouman
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.)
Thales Nederland BV
Original Assignee
Thales Nederland BV
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 Thales Nederland BV filed Critical Thales Nederland BV
Publication of EP0421514A1 publication Critical patent/EP0421514A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F19/00—Fixed transformers or mutual inductances of the signal type
    • H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
    • H01F19/08—Transformers having magnetic bias, e.g. for handling pulses
    • 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
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2847—Sheets; Strips

Definitions

  • the invention relates to a pulse transformer for the transformation of low-voltage pulses to high-voltage pulsesl which is equipped with a primary winding suitable for connection to a pulse transformer generating low-voltage pulses, a secondary winding provided with high-voltage terminals, and a transformer core, which is at least partly surrounded by the primary and secondary windings.
  • This type of pulse transformer can be used in a radar transmitter for the generation of radar transmit pulses.
  • the transformer is then placed between a pulse forming network and a high power tube, such as a magnetron or a klystron.
  • the transformer is required to transform voltage pulses, generated by the pulse forming network, of e.g. several hundred volts, thousands of amperes and a length in the order of microseconds, to voltage pulses of tens of kilovolts and tens of amperes.
  • the transformed pulses are applied to the klystron or magnetron for the generation of microwave pulses.
  • microwave pulses must be generated at a certain repetition rate, the intervals between consecutive pulses being used by a radar receiver to collect echoes of emittted pulses.
  • the pulses need to have steep edges.
  • Pulses having less steep edges may be caused by what is known as the leakage inductance of the pulse transformer. This occurs if the coupling between the primary and secondary winding of the transformer is less than optimal. Then, the electromagnetic fields generated by the primary and secondary windings are not fully coupled.
  • Supply leads too, may contribute to the leakage inductance, as well as the non-conducting spacing which, to achieve the necessary insulation, is present between windings and core.
  • a toroidal core with toroidal windings around it will keep the magnetic flux mainly contained within the core.
  • a disadvantage is that much interspace is needed for the insulation between the primary and secondary windings, the insulation space in turn having an adverse effect on the coupling between the windings.
  • the pulse transformer according to the invention has for its object to provide a transformer exhibiting little leakage inductance by limiting to a large extent the spacing between the windings and between windings and core.
  • the pulse transformer is equipped with connection means between the secondary winding and the transformer core for connecting the high voltage to the transformer core, the secondary winding, for at least part of its width, being surrounded by the entire primary winding.
  • the pulse transformer featuring a primary winding in the form of a foil with conductive material, wound around a secondary winding which is also in the form of a conducting foil, the potential difference between successive layers is small.
  • a further reduction of the leakage inductance is achieved in an embodiment where the transformer core is clamped, by means of the primary winding, to an electrically conducting support frame which comprises insulated parts, a current supplying part and a current draining part having a contact surface with, respectively, the conducting side of a current supplying lead and a current draining lead of the primary winding. Consequently, the space between the primary and secondary windings can be limited to a minimum and a well-defined electrical connection is obtained.
  • the pulse transformer according to the invention can be used in a radar transmit chain as depicted schematically in Fig. 1.
  • a pulse generator 2 connected to power supply 1, generates pulses with a length and at a repetition rate which are suitable for radar.
  • the pulse generator 2 comprises known pulse forming means, such as networks incorporating delay lines, and switching means using, e.g. thyristors.
  • the generated pulses are applied in the usual way via a fast saturable coil 3 to the pulse transformer 4.
  • the coil 3 blocks the pulses until the switching means in the pulse generator 2 have become fully conductive, to prevent power loss across the switching means.
  • the pulses applied to the pulse transformer 4 have characteristic pulse lengths of about 1 ⁇ s, characteristic peak voltages of about 400 v and characteristic peak currents of about 8000 A.
  • the pulse transformer 4 transforms these low-voltage pulses to high-voltage pulses with characteristic peak voltages of 80 kV and peak currents of 40 A.
  • the achieved transformation ratio is thus 1 : 200 in this case, which is considerably higher than customary for pulse transformers.
  • the high-voltage pulses are subsequently applied to a radar transmitter 5, provided with a high power tube, such as a magnetron or klystron, which on the basis of the applied pulses generates microwave pulses with corresponding pulse lengths. Finally, the microwave pulses are emitted by an antenna 6.
  • An embodiment of the pulse transformer according to the invention illustrated in Fig. 2, comprises a transformer core 7, primary windings 8 and secondary windings 9.
  • the transformer core 7, for which conventional material is used is built up from two tightly joined U-shaped parts forming a magnetic circuit, on two facing parts of which the windings 8 and 9 have been mounted.
  • the core may also be E-shaped, however, with a primary and secondary winding wound around all three core legs, or U-shaped with a primary and secondary winding on only one leg.
  • the principal point is that primary winding 8 should enclose the secondary winding as tightly as possible, to achieve a proper couping.
  • the primary winding 8 which in this case is in the form of a foil, is clamped through connections 13, 14, 15 to a support frame consisting of three parts 10, 11 and 12.
  • the parts 10, 11 and 12 of the support frame are made from electrically conducting material, the part 12 being electrically insulated from the parts 10 and 11 by an insulating layer 16.
  • Part 12 makes electrical contact with a part of the electrically conducting side of the primary winding 8, which part is clamped by the connection 14.
  • the side of the primary winding 8 adjoining the transformer core 7 is not provided with an insulating layer.
  • the parts 10 and 11 make electrical contact with the leads of the primary winding 8 which are clamped by the connections 13 and 15.
  • the parts 10 and 11 are subsequently connected electrically, through connections 17, to a conducting plate 18.
  • the part 12 protrudes through an opening of the plate 18, and is clamped on the opposite side of it through connections 19 and 20.
  • a foil 21 is inserted, with two conductive sides which are separated by an insulation layer.
  • the foil 21 is connected to the pulse generator 2 via the saturable coil 3.
  • the primary current path then runs via the side of the foil 21 which makes contact with the part 12, the part 12 proper, the primary winding 8, the parts 10 and 11, the plate 18 and the side of the foil 21 which makes contact with plate 18. Between the plate 18 and part 12 there is further the coil 3.
  • the primary winding 8 is preferably a foil with on one side a conducting layer.
  • the advantage is that the potential differences between the layers remain limited to, in this case, 400 V per layer. Consequently little space is needed for inter-layer insulation and the arrangement can be quite compact, which has a favourable effect on the leakage inductance and the coupling.
  • the parts of the secondary winding 9 which are nearest to the primary winding 8 and those which are nearest to the transformer core 7 are provided with low-voltage leads 22 and high-voltage leads 23, respectively, such that they are externally connectable.
  • the high-voltage leads 23 are electrically linked to the transformer core 7 through a core-surrounding clamping ring 24.
  • the secondary winding 9 is wound on a coil former (not shown in the figure), which freely surrounds the transformer core 7.
  • One of the high-voltage leads 23 is connected to the core 7 by way of an AC coupling in the form of capacitor 25, which forms a low impedance to the generated pulses but, conversely, a high one to a low-frequency AC voltage, applied in the customary manner across the secondary winding 9, to power the filament of a high power tube, when connected.
  • the core 7 can be electrically linked with the secondary winding.
  • part of the secondary winding 9 is wound directly on the core 7, no coil former being used in this case.
  • the secondary winding 9 may take the form of a wire winding, but then more space will be needed for insulation.
  • Fig. 3 is a side view of the pulse transformer according to the line A-A in Fig. 2.
  • the low-voltage leads 22 are kept as far as possible removed from the transformer core 7.
  • the ratio between the width of the primary winding 8 and the width of the secondary winding 9 determines the transformer characteristics to a considerable extent.
  • the secondary winding 9 is made wider than the primary winding 8.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Multimedia (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Radar Systems Or Details Thereof (AREA)
EP90202532A 1989-10-05 1990-09-25 Impulstransformator Withdrawn EP0421514A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8902474A NL8902474A (nl) 1989-10-05 1989-10-05 Pulstransformator.
NL8902474 1989-10-05

Publications (1)

Publication Number Publication Date
EP0421514A1 true EP0421514A1 (de) 1991-04-10

Family

ID=19855402

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90202532A Withdrawn EP0421514A1 (de) 1989-10-05 1990-09-25 Impulstransformator

Country Status (9)

Country Link
EP (1) EP0421514A1 (de)
JP (1) JPH03171706A (de)
KR (1) KR910008754A (de)
AU (1) AU6370290A (de)
CA (1) CA2026136A1 (de)
NL (1) NL8902474A (de)
NO (1) NO904311L (de)
PT (1) PT95391A (de)
TR (1) TR25672A (de)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB204474A (en) * 1922-08-16 1923-10-04 Veifa Werke Ag Improvements in or relating to high tension electric transformers
GB766946A (en) * 1953-12-12 1957-01-30 Philips Electrical Ind Ltd Improvements in or relating to high-voltage transformers
US2998583A (en) * 1956-02-13 1961-08-29 Willis G Worcester Electrical apparatus and electromagnetic coils and method of making the same
US3617854A (en) * 1970-04-20 1971-11-02 Raytheon Co Pulse transformer
NL7405428A (nl) * 1974-02-13 1975-08-15 Benteler Werke Ag Inrichting voor het overdragen van gelijkstroom oge stroomsterkte en geringe rimpel naar ende elektrodeschijven bij het rolnaad- standsstomplassen.
EP0072151A1 (de) * 1981-08-08 1983-02-16 The Marconi Company Limited Transformatoren
DE3534006A1 (de) * 1985-09-24 1987-03-26 Siemens Ag Pulstransformator

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB940500A (en) * 1959-12-02 1963-10-30 Noel Ebenezer Morris Brydon Improvements relating to the construction of underground buildings
US3184893A (en) * 1960-04-11 1965-05-25 Contact Foundation Inc Contact foundation method
SE469726B (sv) * 1990-04-30 1993-08-30 Outokumpu Oy Vertikal pelarbrytning som framskrider uppifraan nedaat

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB204474A (en) * 1922-08-16 1923-10-04 Veifa Werke Ag Improvements in or relating to high tension electric transformers
GB766946A (en) * 1953-12-12 1957-01-30 Philips Electrical Ind Ltd Improvements in or relating to high-voltage transformers
US2998583A (en) * 1956-02-13 1961-08-29 Willis G Worcester Electrical apparatus and electromagnetic coils and method of making the same
US3617854A (en) * 1970-04-20 1971-11-02 Raytheon Co Pulse transformer
NL7405428A (nl) * 1974-02-13 1975-08-15 Benteler Werke Ag Inrichting voor het overdragen van gelijkstroom oge stroomsterkte en geringe rimpel naar ende elektrodeschijven bij het rolnaad- standsstomplassen.
EP0072151A1 (de) * 1981-08-08 1983-02-16 The Marconi Company Limited Transformatoren
DE3534006A1 (de) * 1985-09-24 1987-03-26 Siemens Ag Pulstransformator

Also Published As

Publication number Publication date
NL8902474A (nl) 1991-05-01
TR25672A (tr) 1993-07-01
CA2026136A1 (en) 1991-04-06
KR910008754A (ko) 1991-05-31
NO904311D0 (no) 1990-10-04
JPH03171706A (ja) 1991-07-25
PT95391A (pt) 1992-05-29
AU6370290A (en) 1991-04-11
NO904311L (no) 1991-04-08

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