JP3623858B2 - High frequency transformer winding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a winding of a high frequency transformer used as a coil of a high frequency transformer.
[0002]
[Prior art]
In recent years, for example, in the field of automobiles, various electric vehicles using a charging type battery have been proposed and developed.
In a conventional electric vehicle, when a battery of this charging method is used, as a power source for charging, it is simply transformed to a predetermined voltage using a transformer having a commercial power frequency, and rectified by a diode to obtain a DC voltage. Alternatively, it has been proposed that a commercial AC power supply is rectified and converted to DC and a required DC voltage is obtained by a DC-DC converter.
[0003]
Further, in various electric vehicles using such a charging type battery, for example, from the viewpoint of safety measures such as prevention of contact failure and ease of use, it is easy to attach and detach, and there is no contact by a metal conductor or the like, so-called non-contact. Contact-type chargers are desired and are under consideration.
[0004]
Therefore, as such a non-contact type charger, for example, a primary winding is wound around a detachable primary core, and a secondary winding is separated from a secondary core separated and fixed from the primary side. A transformer wrapped around is proposed.
Usually, in such a charger, a large amount of power is required because the transformer requires a large amount of power, but this can be solved by using a high-frequency transformer with a high switching frequency.
[0005]
[Problems to be solved by the invention]
By the way, as a winding used in such a high-frequency transformer, for example, a conducting wire having a round cross section is conceivable. However, in such a conducting wire, the degree of coupling between the primary winding and the secondary winding decreases. This causes inconveniences such as leakage magnetic flux.
Therefore, as such a winding, for example, a copper foil is proposed. That is, this is prepared by preparing a predetermined number of thin copper conductors cut into a circular shape and welding them or bending a thin copper conductor formed continuously. .
[0006]
[Problems to be solved by the invention]
However, windings using such copper foil have good coupling, but the eddy current loss increases, and the problem is that the efficiency of the output power cannot be improved as much as the temperature of the windings rises. Has occurred.
[0007]
In view of the above-described circumstances, an object of the present invention is to provide a winding of a high-frequency transformer that can suppress eddy current loss and can effectively improve the efficiency of output power.
[0008]
[Means for Solving the Problems]
In other words, the invention according to claim 1 is a winding of a high frequency transformer used as a coil of a high frequency transformer, and two conductive wires using a good conductor such as a copper wire whose surface is insulated are fixed together. A large number of conductor assemblies were prepared, and these were wound along the inner peripheral wall of the mold to form a strip-like coil having a rectangular cross section in which the conductors were stacked in two upper and lower stages, and the conductor assembly The body is wound while dripping an adhesive at the time of winding, and the belt-like coil is wound around an appropriate core as a winding to constitute a coil of a high frequency transformer.
[0009]
In the invention according to claim 2, the strip coil is made of a litz wire formed by twisting a plurality of conductive wires.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a winding of a high-frequency transformer according to the present invention. The winding 1 of this high-frequency transformer has a conductor 10 having an outer peripheral surface coated with an insulating coating film as an example for each turn. It is laminated in two stages, and has a rectangular cross section (band coil) and is wound into a perfect circle for 4 turns (of course not limited to this number of turns), and the secondary core of the high frequency transformer shown in FIG. 3 winding 3A. In this embodiment, in addition to this, a winding having the same cross-sectional shape is wound four turns (not limited to this number of turns) and used as the winding 4A of the core 4 on the primary side.
[0011]
As an example, as shown in FIG. 2, the winding 1 is integrated with an appropriate (insulating) resin so that the conductors 10 are arranged in two upper and lower stages and arranged in parallel to fill the gap between the conductors 10. In particular, here, a thermosetting material is used as an adhesive (resin).
The shape of the winding 1 in this embodiment is configured to be a perfect circle as a whole (excluding the drawer portion), but an appropriate shape (in this embodiment, for example, the internal space shown in FIG. It is sufficient to arrange and mold in a tightly wound state inside the mold 1A having a shape). In this embodiment, the conducting wire 10 is not twisted, but of course a stranded wire (Litz wire) may be used.
[0012]
That is, as shown in FIG. 3, the winding 1 has, for example, a large number of (conducting wire 11) (firstly having a certain degree of flexibility in the lateral direction) in which two conducting wires are first fixed together in a vertical direction. leave meaning for the present, we are disposed along the inner peripheral wall of the mold 1A these conductors assemblies 11 in this order, respectively (wound), if such as a rectangular cross (almost flat) However, other appropriate methods can be adopted. Moreover, what is necessary is just to wind the conducting wire assemblies 11 while dripping an adhesive agent at the time of winding.
[0013]
Next, the power (conversion) efficiency obtained when used as the winding of the high-frequency transformer according to this embodiment will be described.
As shown in FIG. 5, the output current of the same side-by-side type high-frequency transformer using the winding 1 of this embodiment and the winding using a copper foil is output using an appropriate circuit. Experiments on output voltage, output power, power efficiency, etc. were conducted. Here, the input voltage was a rectangular wave of 50 V and 100 kHz.
Each power efficiency η at this time, that is, the ratio of the output power P _O to the input power P _I, that is, η = P _O / P _I was obtained, and the result shown in FIG. 5 was obtained. Here, the solid line X is data in the transformer using the winding 1 according to this embodiment, and the broken line Y is data in the transformer using copper foil. As can be seen from the graph shown in FIG. 5, it is found that the power efficiency is always higher in the coil using the winding 1 than in the copper foil.
[0014]
Note that the present invention is not particularly limited to a configuration in which a conducting wire is bundled and wound in a perfect circle shape as in this embodiment, for example, a coil formed in a square shape as shown in FIG. Various shapes such as a coil formed in a polygonal shape (for example, hexagonal shape or octagonal shape) and the like not shown are applicable.
[0015]
【The invention's effect】
As described above, according to the present invention, a large number of conductive wires using a good conductor such as a copper wire are assembled in a cross-sectional strip shape, and the assembled conductive wires are integrally bonded and solidified to form an appropriate shape for the strip conductive wire. Is formed as a coil of a high-frequency transformer by winding the strip coil around a suitable core as a winding to efficiently suppress the reduction in eddy current loss. As a result, the efficiency of the output power can be increased.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing windings of a high-frequency transformer according to the present invention.
2 is a cross-sectional view of the winding shown in FIG.
3 is an explanatory view showing a method of forming the winding shown in FIG. 1. FIG.
4 is a schematic cross-sectional view (insert type) showing a high-frequency transformer using the winding shown in FIG. 1. FIG.
FIG. 5 is a graph showing a result of a comparative experiment of power efficiency between the winding shown in FIG. 1 and a coil using copper foil.
FIG. 6 is a schematic perspective view showing another embodiment of the present invention.
[Explanation of symbols]
1, 2 Winding 10 Conductor 11 Conductor assembly

Claims (2)

A winding of a high-frequency transformer used as a coil of a high-frequency transformer,
Two conductors (10) using a good conductor such as a copper wire whose surface is insulated are vertically fixed together, that is, a large number of conductor assemblies (11) are prepared, and these are formed in the mold (1A). Wrapping along the inner peripheral wall to form a strip-like coil having a rectangular cross section in which the conductive wire (10) is laminated in two stages, and an adhesive is dropped when winding the conductive wire assemblies (11). While winding,
A winding of a high frequency transformer, wherein the strip coil is wound around a suitable core as windings (1) and (2) and configured as a coil of a high frequency transformer. The winding of the high frequency transformer according to claim 1, wherein the shape of the winding (1) or (2) is formed into a perfect circle shape or a square shape as a whole except for a lead-out portion .

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