Classifications

• • 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
  • H01F27/40—Structural association with built-in electric component, e.g. fuse
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/4902—Electromagnet, transformer or inductor

Definitions

• the present invention relates to transformers for a static converter and more particularly to the transformer-rectifier assembly.
• transformers are generally used whose primaries and secondaries are coaxial, that is to say superimposed in the radial direction.
• the coils are made with enameled wire or with copper strip (planar coil).
• Axial stacking systems have also been described, in particular in French patent FR1 028950A by C. GOSSELIN which explains the use of suitably slit copper blades to form a turn capable of being placed around a core, this in the case of transformers at 50 or 60 Hz, single-phase or three-phase.
• the US patent US4965712A from DUSPIVA ALTER. S and AL also describes the use of coils of cut copper sheet, this time with a core making several turns around the copper strip. This transformer was used in a high frequency circuit.
• the two systems which have just been described integrate rectification diodes between the secondary blades. They have in common the disadvantage of having a high leakage inductance, such as to limit the frequency of use and consequently to make the bulky system heavy and expensive.
• the invention avoids these drawbacks since it makes it possible to produce very simple and inexpensive transformers thanks to a high operating frequency.
• the invention relates to a high frequency transformer with integrated rectifiers having primary and / or secondary coils constituted by conductive blades (3) surrounding a single leg of the magnetic core, operating at a frequency between 3 and 50 kHz and comprising:
• the rectification is carried out either according to a two-phase type circuit with 2 diodes with a secondary at midpoint (a), or with a conventional bridge (b), or with a circuit with 2 filtering reactors (c ).
• the rectifying diodes (4) are strongly pressed by suitable means (24) between the conductive blades (3) constituting the secondary and collector blades (14), in order to ensure good thermal and electrical contact.
• the collecting blades (14) and the conducting blades (3) are cooled either by circulation of air, or by a circulation of water in the thickness of the blade thanks to channels (25).
• the conductive strips (3) are used as a primer, either directly or with series connection by means of conductive posts (15), staggered along the axes ⁇ 4 and ⁇ 5
• the conductive blades (3) have a U-shape (20) and are used as a primary and attacked by a bridge cutting generator constituted by 4 switches (21) arranged between continuous supply blades ( 22) and (23), the pattern constituting the bridge being advantageously reproduced a large number of times, the blades (20) being interposed between coils (2) or plates (3) used as secondary
• the conducting strips (3) being secondary, the rectifier (a) is produced, n times, by connecting all the midpoints by conducting columns (5), along A ⁇ while the diodes are stacked according to ⁇ 2.
• the diodes can be in position
• the flat coils (2) are produced either by winding in enameled wire along 2 superimposed spirals connected in their center, one centripedal, the other centrifugal, or by 2 copper plates cut in a spiral and connected to each other by a weld in the center of the coil.
• the invention is used for the construction of static converters, whether they are voltage raisers or lowerers.
• the invention is used to power welding machines, by point or of TIG, MIG, ARC type ... or even plasma machines for shooping, plasma cutting etc ...
• the conductive plate (3) consists of a flat heat pipe.
• FIG. 1 shows the block diagram of the electronic circuit of a transformer with its rectification circuit which can be of type a, b or c.
• FIG. 2 shows, in exploded view, a step-down transformer and the associated rectifier.
• FIG. 3 shows a section of the converter shown diagrammatically in Figure 2, showing in particular the connection of the middle point of the secondary, in the case of a rectifier of type a.
• FIG. 4 represents one of the plates (3) forming the secondary of the converter of FIG. 3.
• FIG. 5 shows an exploded view of an impedance boost converter.
• FIG. 7 shows a bridge cutting generator integrated into the transformer structure, which allows to attack the primaries (20).
• FIG. 8 shows a primary coil (20) intended to be driven by the generator of Figure 7, on which are represented the transistors (21) constituting the branches of the bridge.
• - Figure 9 shows the means (24) for clamping the stack of diodes; - Figure 10 shows the cooling channels of the conductive plates (3) and the collector plates (14).
• FIG. 11 shows a system using the rectification circuit of type (c).
• FIG. 12 shows a section of the previous system in which the inductors are made by means of a turn passing through the cores (25).
• the invention can be broken down into 2 categories: converters lowering impedance and raising impedance.
• Case 1 the output voltage is smaller than that continuously feeds the cutting bridge, while in the second case it is higher.
• a converter is constituted by the implementation of several elementary cells such as that shown diagrammatically in FIG. 1.
• the output connection of the cells can be carried out in series in the case of a rise in impedance (FIG. 6a) or in parallel for the impedance reducers (FIG. 6b) or again according to an infinity of combinations in series-parallel, so as to best adapt the impedances.
• This stack is also very advantageous from a thermal point of view because it allows the dissipation of the calories dissipated in the transformer coils, by means of the conductive plates (3) which are themselves cooled, either by forced air or by a circulation of water inside the plates itself, or again by the use of a process based on heat pipes.
• These conductive plates (3) can advantageously be made of copper or aluminum and constitute both the primary and the secondary or both simultaneously.
• This stack is still interesting from an economic and industrial point of view because it allows the construction of a large variety of converters, in a wide range of power from standard elements which can be connected according to a large number of series combinations. - parallel, both in primary and secondary.
• the arrangement of silicon diodes (4) advantageously in the form of thin pellets (fusions on molybdenum for example), directly in contact with the conductive (3) or collector (14) plates, makes it possible to eliminate the connection wires and consequently reduce the bonding inductance between the transformer and the rectifiers. This reduction is further increased in certain cases, by the placing in parallel of a large number of elementary circuits.
• the invention makes it possible to reduce the parasitic inductance in series with the switching bridge, which is the sum of the leakage inductance of the transformer and the connection inductance. This allows operation at a higher frequency than that obtained with conventional transformers. This results in a reduction in size, mass and ultimately the cost of the converters.
• converters operating at 5 kHz could be produced, capable of delivering a permanent power of 250 kW, contained in a shoe box!
• the elementary cell of the converter shown in FIG. 1 makes it possible to understand its operation. They essentially consist of a ferromagnetic core (1), made of ferrite or silicon iron laminated in thin layers (0.05 to 0.1 mm) or also of amorphous material. Around the core (1) are arranged:
• a primary winding (P) which may, depending on the case, be constituted by a metal plate (3), advantageously made of copper or aluminum, cooled by air or by water or else a coil of enameled wire with double spiral (2).
• S secondary winding
• the secondary circuit can be constituted simply by a turn produced by a plate (3) with straightening along the circuit (c).
• the elementary cell given in FIG. 1 is provided with a rectification circuit using two diodes (D). It may include a filtering circuit (C), but this can also be placed at the output of the converter, that is to say after all the elementary cells have been connected in parallel as shown diagrammatically in FIG.
• the static converter is used to obtain high currents under a low voltage.
• a power supply for spot welding capable of delivering 10,000 A at a voltage of 10 V.
• 5 cells constituted as shown exploded in FIG. 2 that is to say each comprising two copper secondary plates (3) surrounding a primary coil (2).
• the section given in FIG. 3 allows a better understanding of the construction of this circuit.
• the 2 plates (3) are shown in Figure 4.
• the diodes can be placed either in position (12), in this case the midpoint is in (13), or in position (13) (midpoint in 13) according to the diagram in Figure 2.
• a flat coil produced either by winding in two superimposed spirals of enameled wire connected together by the center, or by stacking plates of a coil connected together by conductive balusters staggered according to the diagram in Figure 5.
• This type of coil has the advantage of having a thin thickness allowing good evacuation of calories and having its outputs on the outside without causing excess thickness.
• the connection of the midpoints of the primaries which constitutes one of the straightening outlets is carried out by tightening along the axis ⁇ i of copper spacer (5) by means of a steel rod passing through the hole (12) provided in the plate (3).
• the rectifier diodes are produced by directly placing the silicon chips (4), often called fusion between the plates (3) and (14) along the axis ⁇ 2 . thus the diodes connect the ends (13) of the coils cut between the plates (3), thanks to the slot (11) to the collection blades (14) which constitute the other outlet of the collector. So that the diode-copper plate contacts are not very resistive, the stack must be tightened tightly along the ⁇ 2 axis, using screws or filtered steel rods.
• the primaries, all connected in series according to Figure 6b, will be supplied by a symmetrical bridge cutting the rectified sector.
• a frequency which can range from 3 to 10 kHz. If for example, this is 5 kHz and if a core with a useful cross-section of 5 cm 2 is used , working on a peak induction of IT, the primary must have 55 turns. This will be achieved, for example by 5 coils (2), of 11 turns each. Thus, the transformation ratio will be 55.
• the diodes and the transformer are cooled from the plates (3) and the collectors (14), which are cooled by water or by air.
• the static converter, object of the invention is used as a high voltage source, which may also be called " impedance boost converter ".
• the plates (3) are used to constitute the primaries as shown diagrammatically in FIG. 5. To better understand the invention, let us place our in the concrete case of a high-voltage power supply delivering a voltage of 5600 volts.
• the nucleus has a section of 50 cm 2 and that it supports a peak induction of 0.28T at the frequency of 5kHz.
• the number of primary turns that is to say of plates (3) connected in series by the set of connection columns Ai and ⁇ 2 will be 20.
• the connections of the plates will be made by a series of spacers (15) alternately insulating or conductive.
• the plates (3) comprising a lumen (10) to let the core pass as well as a slot (11) necessary to form a turn, are stacked alternately face F at the top then at the bottom, then at the top etc. ..so that the turns turn in the same direction thus forming a spiral winding.
• FIG. 5 shows a cell using two coils (2) connected in a suitable direction so that the two output wires (16) and (17) deliver square slots in phase opposition. Under these conditions, the diodes (18) and (19) make it possible to carry out a so-called "two-phase" rectification.
• FIG. 6 b The connection of all the elementary cells is carried out as shown diagrammatically in FIG. 6 b. With 10 primary plates (3), 5 cells can be made. Each coil must have 20 turns. As before, the cooling of the transformer can advantageously be carried out by means of the plates (3); these can be cooled by air or water. in Figure 6b, there is shown a filter cell L C placed on the output of the converter.
• the transformer integrates between its conductive plates (20) of slightly different shape, this time used as a primary, a series of generators constituted by bridges with the aim this time of reducing the inductance of
• FIG. 7 represents this generator, which as before, is composed of several cells allowing the realization of the primary-secondary alternation which we have seen that it constitutes the foundation of the invention.
• transistors (21) in fairly flat housings, say for example S 247.
• these transistors can be MOS or IGBT. They are connected according to the conventional diagram of the bridge, between continuous supply plates (22) of polarity + and (23) of polarity -.
• capacitors (C) as close as possible to the transistors (21), between the plates (22) and (23).
• the secondary is carried out as above with integrated rectifiers, provided that it is split. Fractionation can be obtained, even in the case of a single coil, in this case it suffices to connect in series flat coils (2) or plates to a turn (3) connected in series by means of conductive posts (15 ).
• an adjustment is carried out according to the diagram (c).
• the diodes (4) are stacked between the secondaries (3) and the collector plates (14) along the axes ⁇ 6 and ⁇ (see FIG. 11).
• the plates (3) can be extended in order to produce the inductances L by placing two cores (25) between the rectifier and the output as shown diagrammatically in FIG. 12.
• the cooling can be carried out simply by giving the plates (3) and (14), a sufficient surface on which a forced circulation of air is caused.
• a heat transfer liquid water, glycol, coolanol, freon, oil etc.
• the plates are made up of two copper sheets. Channels are etched into one of them (see Figure 10) and the two sheets are brazed on top of each other, so that the liquid can be circulated through the thickness of the sheet. This is introduced for example through the orifice (26) and extracted by (27), this by means of a suitable set of waterproof and hollow spacers, not shown in the figures. It is thus possible to channel the liquid up to the level of the diode.
• the invention can be used in all cases where a static converter is required. Let us cite as an indication some typical applications of the invention: - generator with very low impedance intended to equip spot welding machines.

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• 2000
  • 2000-07-21 FR FR0009697A patent/FR2812122B1/fr not_active Expired - Fee Related
• 2001
  • 2001-07-19 DE DE60134745T patent/DE60134745D1/de not_active Expired - Lifetime
  • 2001-07-19 JP JP2002514744A patent/JP2004515906A/ja not_active Withdrawn
  • 2001-07-19 EP EP01956615A patent/EP1301932B1/de not_active Expired - Lifetime
  • 2001-07-19 AU AU2001278543A patent/AU2001278543A1/en not_active Abandoned
  • 2001-07-19 US US10/333,445 patent/US6788184B2/en not_active Expired - Fee Related
  • 2001-07-19 AT AT01956615T patent/ATE400881T1/de not_active IP Right Cessation
  • 2001-07-19 WO PCT/FR2001/002361 patent/WO2002009128A1/fr active IP Right Grant

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