JPH1022131A - Winding of high frequency transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress eddy current loss and to improve output voltage by using a band coil as a winding of a high frequency transformer. SOLUTION: A plurality of good conductors 10 consisting of copper wire, etc., are bundled in the form of band, and the bundle of conductors 10 is integrally glued and solidified to form a band coil of thin plate having a plurality of windings in proper form. The band coil is wound around a proper core to use as a coil of a high frequency transformer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency transformer winding used as a high frequency transformer coil.

[0002]

2. Description of the Related Art In recent years, for example, in the field of automobiles,
Various electric vehicles using rechargeable batteries have been proposed and developed. In a conventional electric vehicle, when a battery of this charging system is used, the voltage is simply converted to a predetermined voltage using a transformer of a commercial power supply frequency as a power supply for charging, and rectified by a diode to obtain a DC voltage. Alternatively, it has been proposed to rectify a commercial AC power supply and convert it to DC, and obtain a required DC voltage with a DC-DC converter.

[0003] In addition, various electric vehicles using such a battery of a charging system are easy to attach and detach, and have no contact by a metal conductor or the like, for example, in view of safety measures such as contact failure prevention and ease of use. A so-called non-contact type charger is demanded and studied.

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 wound around a secondary core separated and fixed from the primary side. A transformer having a secondary winding wound thereon has been proposed. Usually, in such a charger, a large power is required, so that the transformer is easily increased in size. However, this can be solved by using a high-frequency transformer having a high switching frequency.

[0005]

As a winding used in such a high-frequency transformer, for example, a conductor having a round cross section can be considered. In the case of such a conductor,
The degree of coupling between the primary winding and the secondary winding is reduced, causing inconveniences such as generation of leakage magnetic flux. Therefore, a winding using, for example, a copper foil has been proposed as such a winding. That is, this is formed by preparing a predetermined number of sheet-like copper conductors hollowed out in a circular shape, welding them, or bending a continuous sheet-like copper conductor. .

[0006]

However, the winding using such a copper foil has a good coupling, but has a large eddy current loss, and has a problem that the temperature of the winding rises and the efficiency of the output power increases. There is a problem that improvement cannot be achieved as much as desired.

In view of the above circumstances, it is an object of the present invention to provide a high-frequency transformer winding capable of suppressing eddy current loss and effectively improving output power efficiency. It is.

[0008]

That is, the invention according to claim 1 is a winding of a high frequency transformer used as a coil of a high frequency transformer, wherein a good conductor such as a copper wire whose surface is insulated is used. A large number of conductors are assembled and integrated to form a cross-section strip-shaped conductor assembly, and the cross-section strip-shaped conductor assembly is wound a plurality of times to form a thin strip-shaped coil, and the strip-shaped coil is appropriately used as a winding. And wound as a coil of a high-frequency transformer.

In the invention according to a second aspect, the strip-shaped coil is formed of a litz wire formed by twisting a plurality of conductive wires.

[0010]

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 the high-frequency transformer is formed by using, as an example, each conductor 10 having an outer peripheral surface coated with an insulating coating film for each turn. It is a two-layer stack, having a rectangular cross section (a band-shaped coil), and is wound in a perfect circle shape for 4 turns (of course, not limited to this number of turns), and is a secondary-side core of the high-frequency transformer shown in FIG. 3 is used as the winding 3A. Further, in this embodiment, a winding having the same cross-sectional shape is wound four turns (of course, the number of windings is not limited to this number) and used as the winding 4A of the core 4 on the primary side.

As shown in FIG. 2, for example, the windings 1 are arranged in two upper and lower stages and arranged in parallel, and are integrally formed of an appropriate (insulating) resin so as to fill a gap between the windings 1. In particular, a thermosetting adhesive (resin) is used here. Although the shape of the winding 1 of this embodiment is configured to be a perfect circle as a whole (excluding the drawer portion), an appropriate shape (in this embodiment, for example, the internal space shown in FIG. May be arranged in a tightly wound state without any clearance in the inside of the molding die 1A having the same shape. In this embodiment, the conductor 1 is not twisted, but of course, a twisted wire (Litz wire)
May be used.

That is, as shown in FIG. 3, the winding 1 has, for example, a structure in which two conducting wires are first fixed vertically (a binding wire 11) (a certain degree of flexibility in the horizontal direction). ) (In this embodiment, for example, an input voltage of 10
Assuming 0 kHz, a conductor having a diameter of 0.1 to 0.3 mm
0) are prepared, and these conductor aggregates 11 are prepared.
May be sequentially arranged (wrapped) along the inner peripheral wall of the molding die 1A so as to have a rectangular cross section (substantially flat plate shape), but other appropriate methods can be adopted. It is. Moreover, what is necessary is just to wind around each wire assembly 11 while dripping an adhesive at the time of winding.

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 two types of coils of the same side-by-side type high-frequency transformer using the winding 1 of this embodiment and those using a copper foil is determined by using an appropriate circuit. Experiments were conducted on output voltage, output power, power efficiency, and the like. Here, the input voltage was a rectangular wave of 50 V and 100 kHz.
When each power efficiency η at this time, that is, a ratio of the output power P _{O to} the input power P _I, that is, η = P _O / P _I was obtained.
The result as shown in FIG. 5 was obtained. Here, the solid line X
Is a transformer using the winding 1 according to this embodiment, and a broken line Y
Shows data from a transformer using copper foil. As can be seen from the graph shown in FIG. 5, it is understood that the coil using the winding 1 always has higher power efficiency than the coil using the copper foil.

The present invention is not limited to the configuration in which the conductors are bound and wound in a perfect circular shape as in this embodiment, and for example, as shown in FIG. Various shapes such as the formed coil 2 and a coil formed in a polygonal shape (for example, hexagonal or octagonal) not shown can be applied.

[0015]

As described above, according to the present invention, a large number of conductors using a good conductor such as a copper wire are assembled in a band shape in a cross section, and the assembled conductors are integrally bonded and bonded.
It is solidified to form a thin strip-shaped coil by winding the strip-shaped conductor wire into an appropriate shape a plurality of times, and the strip-shaped coil is wound around a suitable core as a winding to constitute a coil of a high-frequency transformer. The reduction of the eddy current loss can be suppressed efficiently, and 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 a winding of a high-frequency transformer according to the present invention.

FIG. 2 is a sectional view of the winding shown in FIG. 1;

FIG. 3 is an explanatory view showing a method of forming the winding shown in FIG. 1;

FIG. 4 is a schematic sectional view (insert type) showing a high-frequency transformer using the winding shown in FIG. 1;

FIG. 5 is a graph showing a result of a comparison experiment of power efficiency between the winding shown in FIG. 1 and a coil using a 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)

[Claims] 1. A winding of a high-frequency transformer used as a coil of a high-frequency transformer, wherein a large number of conductive wires using a good conductor such as a copper wire having an insulated surface are assembled and integrated to form a strip-shaped conductive wire assembly. And forming a thin strip-shaped strip coil by winding the wire assembly having a cross section in a plurality of turns, and winding the strip coil into an appropriate core as a winding to form a coil of a high-frequency transformer. Features high frequency transformer windings. 2. The coil according to claim 1, wherein the strip-shaped coil is formed of a litz wire formed by twisting a plurality of conductive wires.
The winding of the high-frequency transformer according to 1.