Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F30/00—Fixed transformers not covered by group H01F19/00
  • H01F30/06—Fixed transformers not covered by group H01F19/00 characterised by the structure
  • H01F30/16—Toroidal transformers
• • 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
  • H01F27/2895—Windings disposed upon ring 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
  • H01F27/32—Insulating of coils, windings, or parts thereof
  • H01F27/324—Insulation between coil and core, between different winding sections, around the coil; Other insulation structures
  • H01F27/325—Coil bobbins
• • 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
  • H01F27/402—Association of measuring or protective means
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F30/00—Fixed transformers not covered by group H01F19/00
  • H01F30/04—Fixed transformers not covered by group H01F19/00 having two or more secondary windings, each supplying a separate load, e.g. for radio set power supplies

Definitions

• the subject of the invention is an arrangement of windings of a HV insulation transformer for power supply devices with multiple outputs whose outputs must be insulated from the primary side and between each other, to withstand very high voltages.
• High voltage insulation transformers to provide high voltage galvanic insulation. This allows to isolate each output from the input of the power supply device as well as each output from the other output of the supply device.
• the controllers sense primary currents to protect the circuit against overload or shorted output.
• the sensing circuits can be applied to monitor primary currents, which are dependent on secondary currents.
• the isolating transformer comprises a single primary and multiple secondary windings
• the sensing circuit measures total primary current without the possibility of monitoring individual secondary currents.
• the power supply devices with HV insulated transformers having multiple outputs there are separate transformers for each of the outputs, providing galvanic isolation between primaries and secondaries as well as between all of the secondaries.
• the essence of the invention comprising a secondary winding superimposed on a primary winding forming a pair of windings wound on a transformer core is that at least two pairs of windings are placed on the same one common core in such a way that any windings of each pair of windings are not overlapping the neighboring pair of windings.
• the primary windings are connected in parallel and each of the primary winding has a current sensor adapted for measuring the current of its respective secondary winding.
• each pair of windings has an insulation gap situated between the external surface of the primary windings and the internal surface of the secondary windings.
• an insulation shell is inserted having a shape compatible with the shape of the core.
• a series of press-fits are placed for positioning the secondary windings exactly in superposition area on the primary windings.
• the insulation shell is provided with ribs which are distributed radially along the internal side of shell walls on both sides of the shell for proper positioning the core and primary windings.
• the insulation shell is made in the form of a insulation mesh.
• the four pairs of windings are place uniformly.
• the primary windings and the secondary windings are coated with one or more insulation layers.
• the transformer core is made as a solid ferromagnetic body in the shape of a toroid.
• the transformer core is made as one body with the insertion of the other magnetic material having different magnetic permittivity in its magnetic path.
• transformer core is made as a stack of separate ring plates situated one on a top of the other.
• the advantage of the inventive transformer is that it assures the assessment of the individual secondary current of each outputs of the power supply device by sensing the primary current.
• the use of single common core transformer as opposed to the multiple transformers allows the size reduction of the power supply device.
• the subject of the invention is presented in the drawing, where fig.1 shows the schematic circuit diagram of the transformer, fig. 2 - the first embodiment of the transformer windings in an axonometric view, fig. 3 - the second embodiment of the transformer windings in an axonometric view, fig.4 - transformer windings from fig. 3 after detaching a half of the transformer shell.
• the transformer for the power supply device has a magnetic core ring 1 , on which at least two separated primary windings 2 are wound.
• the primary windings are connected in parallel.
• Each primary winding 2 is equipped with a current sensor 3.
• a separate secondary winding 4 is wound in such a way that winding 4 is spatially superimposed on the primary winding 2, where a certain distance is present between the external surface of the winding 2 and the internal surface of the winding 4 forming an insulation gap 5 between them.
• the gap 5 can be filled with a potting insulation material assuring the proper insulation level between both windings 2 and 4, which is not shown in the drawing.
• the primary windings 2 and the secondary windings 4 are forming pairs of windings 6 having one primary and one secondary winding in each pair. All pairs of the windings 6 are distributed uniformly along the perimeter of the core 1 in such a way that the neighboring pairs are not overlapping each other.
• an insulation shell 7 made of plastic is inserted in the gap 5.
• the shell 7 is composed of two halves 7a and 7b and has a shape similar to core 1 , thus covers the core 1 except of primary windings terminals leaded out of the shell 7, which is not shown in the drawing.
• the outer side of the side wall of the shell 7 is provided with a series of press-fits 8 placed on its perimeter in order to position the secondary windings 4 on top of the primary winding 2.
• the shell 7 is provided with ribs 9 which are distributed radially along both inner sides of the side walls.
• the insulation shell 7 can be realized as mesh construction which is not shown in the drawing. In such a case the press-fits 8 are needless.
• the primary windings 2 and the secondary windings 4 can be coated with one or more insulation layers.
• the gap 5 can be eliminated, which means that the primary and the secondary windings of the pair 6 remain in contact.
• the transformer according to the both embodiments of the invention could be placed in an insulating housing and covered with an insulating cover which is not presented in the drawing.
• the housing can be made out of a resin by molding and in such a case, the shell can be omitted, because the resin insulation between the windings replaces the shell.
• the magnetic core 1 is made as a solid ferromagnetic body in the shape of toroid, but it can be made as one body with the insertions of the other magnetic material having different magnetic permittivity. Also the core 1 could be made of some separate ring plates situated one on the top of the other forming a stack. The number of the pairs of windings in the exemplary embodiment is four, but it may be different on the assumption that the pairs 6 do not overlap each other.
• the principle of operation of the inventive transformer is the following. All the primary windings 2 equipped with current sensors 3 are connected in parallel and driven from an AC source inducing voltages in the secondary windings 4. The sensors 3 measure primary currents which are dependent on the secondary ones, so indirectly the sensors sense secondary currents. Even though all pairs of the windings 6 are placed on the same common core 1 , the individual currents flowing through the primary windings 2 are dependent on the currents of their respective secondary windings 4 with negligible impact of the currents of neighboring pairs 6. Each pair of the windings 6 acts like an independent transformer, since the magnetic coupling within each pair of the windings is much higher than between the neighboring pairs, hence the crosstalk between the neighboring windings is negligible.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Transformers For Measuring Instruments (AREA)

Applications Claiming Priority (2)

Publications (1)

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Cited By (3)

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Citations (3)

• 2013
  • 2013-05-29 EP EP13460035.2A patent/EP2808879B1/de active Active
• 2014
  • 2014-03-18 WO PCT/EP2014/000722 patent/WO2014191068A1/en active Application Filing

Patent Citations (3)

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