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EP-4738397-A1 - A FRACTIONAL MATRIX TRANSFORMER

EP4738397A1EP 4738397 A1EP4738397 A1EP 4738397A1EP-4738397-A1

Abstract

The disclosed concepts relate to a matrix transformer comprising a plurality of ferromagnetic legs, a plurality of primary windings, and a plurality of secondary windings. Each secondary winding is wound around each leg a same number of times. For each leg, the sum of the number of turns made by the plurality of primary windings around the respective leg is the same. Further, a total number of turns made by each respective primary winding around the plurality of legs does not equal an integer multiple of the number of legs. As a result, for a given/target number of legs (e.g., due to form-factor requirements), and for a given number of turns of the secondary winding (e.g., only one turn to minimize conduction losses), a greater number of turns ratios between the primary and secondary windings are possible, as the restriction of having the number of turns of each primary winding equal to an integer multiple of the number of legs is removed.

Inventors

  • URSINO, Mario
  • RIZZOLATTI, Roberto
  • MAZZER, Simone

Assignees

  • Infineon Technologies Austria AG

Dates

Publication Date
20260506
Application Date
20241030

Claims (14)

  1. A matrix transformer (100), comprising: a plurality of ferromagnetic legs (110); a plurality of primary windings (120), wherein: for each leg, the sum of the number of turns made by the plurality of primary windings around the respective leg is the same, a total number of turns made by each respective primary winding around the plurality of legs does not equal an integer multiple of the number of legs, the number of primary windings equals the number of legs; and a plurality of secondary windings (130), wherein the number of primary windings equals the number of legs and each secondary winding is wound around each leg a same number of times.
  2. The matrix transformer of claim 1, wherein each of the plurality of primary windings (120) is wound around the legs (110) in a consistent clockwise or anticlockwise turn direction.
  3. The matrix transformer of any of claims 1-2, wherein the plurality of primary windings (110) are connected in series.
  4. The matrix transformer of any of claims 1-3, wherein the plurality of secondary windings (130) are connected in parallel.
  5. The matrix transformer of any of claims 1-4, wherein each secondary winding is wound around each leg one turn.
  6. The matrix transformer of any of claims 1-5, comprising: a first ferromagnetic leg and a second ferromagnetic leg; a first primary winding and a second primary winding, wherein: the first primary winding is wound around the first leg a first number of times, and the second primary winding is wound around the second leg the first number of times, and the first primary winding is wound around the second leg a second number of times, and the second primary winding is wound around the first leg the second number of times, and wherein the first number of times does not equal the second number of times; and a first secondary winding and a second secondary winding, wherein the first secondary winding is wound around the first leg and the second leg a third number of times, and the second secondary winding is wound around the first leg and the second leg the third number of times.
  7. The matrix transformer of claim 6, wherein the first number of times is equal to two, the second number of times is equal to three.
  8. The matrix transformer of claim 6, wherein the first number of times is equal to one, and the second number of times is equal to zero.
  9. The matrix transformer of any of claims 6-8, wherein the third number of times is equal to one.
  10. A hybrid switched capacitor, HSC, converter (10) comprising the matrix transformer (100) of any of claims 1-9.
  11. A method for manufacturing a matrix transformer, the method comprising: providing (210) a plurality of ferromagnetic legs; turning (220) each of a plurality of primary windings around the plurality of ferromagnetic legs, wherein: for each leg, the sum of the number of turns made by the plurality of primary windings around the respective leg is the same, and a total number of turns made by each respective primary winding around the plurality of legs does not equal an integer multiple of the number of legs, and the number of primary windings equals the number of legs; and turning (230) each of a plurality of secondary windings around plurality of legs, wherein the number of secondary windings equals the number of legs and each secondary winding is wound around each leg a same number of times.
  12. The matrix transformer of claim 11, wherein for each of the plurality of primary windings and the plurality of secondary windings, turning (220, 230) the respective primary or secondary winding comprises turning the winding around the legs in a consistent clockwise or anticlockwise turn direction.
  13. The matrix transformer of claim 11 or 12, further comprising connecting (240) the plurality of primary windings in series.
  14. The matrix transformer of any of claims 11-13, further comprising connecting (250) the plurality of secondary windings in parallel.

Description

TECHNICAL FIELD The present disclosure generally relates to matrix transformers, and methods for manufacturing matrix transformers. BACKGROUND A matrix transformer is equivalent to a single transformer divided into a plurality of separate transformers. To convert a classical transformer into a matrix transformer, the leg of the transformer is split into the desired number of legs. The primary windings of the single transformer are divided into the new legs. For example, a primary winding with two turns divided into two legs will be turned once around each leg. The secondary windings are replicated among every leg. The primary windings are then connected in series, and the secondary windings are connected in parallel. The advantage of using a matrix transformer comes from the distribution of the output current across each paralleled secondary winding, leading to a reduction in total resistance and decreased leakage inductance. In particular, the use of a matrix transformer in a DC-DC converter offers several benefits. In general, it provides the ability to achieve higher power density and efficiency compared to traditional transformer designs. This is due to the improved magnetic coupling and reduced leakage inductance, which allows for better energy transfer and reduced power losses. In a matrix transformer, the magnetic circuit is split together with the windings, facilitating a better spread of the current through the windings. The form factor of a matrix transformer typically depends on the number of legs of the matrix transformer. In many applications, a certain form factor may be desired (e.g., a certain length and width). However, in typical matrix transformers, for a given number of legs of the matrix transformer, the number of primary turns needs to be an integer multiple of the number of legs. Accordingly, there exists a need for a matrix transformer with a given form factor with a tunable turns ratio. SUMMARY According to one aspect, there is provided a matrix transformer. The matrix transformer comprises: a plurality of ferromagnetic legs, a plurality of primary windings, and a plurality of secondary windings comprising one secondary winding for each of the plurality of legs. For each leg the sum of the number of turns made by the plurality of primary windings around the respective leg is the same. Further, a total number of turns made by each respective primary winding around the plurality of legs does not equal an integer multiple of the number of legs. The number of primary windings equals the number of legs. Each secondary winding is wound around each leg a same number of times. According to another aspect of the present disclosure, there is provided a hybrid switched capacitor comprising the matrix transformer as described above. According to a further aspect of the present disclosure, there is provided a hybrid switched capacitor converter comprising the hybrid switched capacitor as described above. According to yet another aspect of the present disclosure, a method for manufacturing a matrix autotransformer is provided. The method comprises: providing a plurality of ferromagnetic legs; turning each of a plurality of primary windings around the plurality of ferromagnetic legs, wherein: for each leg, the sum of the number of turns made by the plurality of primary windings around the respective leg is the same, and a total number of turns made by each respective primary winding around the plurality of legs does not equal an integer multiple of the number of legs. The number of primary windings equals the number of legs. The method further comprises turning each of a plurality of secondary windings around plurality of legs, wherein the plurality of secondary windings comprises one secondary winding for each of the plurality of legs, wherein each secondary winding is wound around each leg a same number of times. Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example with reference to the accompanying drawings, in which: FIG. 1 presents a circuit diagram of a hybrid switched capacitor, HSC, converter comprising a matrix transformer;FIG. 2 shows the connected and routing of the primary and secondary windings around the legs of the matrix transformer included in the HSC converter of FIG. 1;FIG. 3 presents a classical transformer and its known matrix transformer equivalent;FIG. 4 presents a matrix transformer according to an embodiment of the invention, and a classic transformer equivalent;FIG. 5 presents another matrix transformer according to an embodiment of the invention, and a classic transformer equivalent;FIG. 6 presents a further matrix transformer according to an embodiment of the invention, and a classic transformer equivalent;FIG. 7 presents a flow diagram of a method for manufacturing a ma