JP2505721Y2 - Converter transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a converter transformer for a switching power supply used in various video equipment and industrial equipment.

2. Description of the Related Art In recent years, converter transformers have been increasing in frequency and downsizing, but it is said that temperature reduction measures are important for downsizing.

The conventional foil wound converter transformer will be described below.

FIG. 3 is a structural sectional view of a conventional foil wound converter transformer. In FIG. 3, 8 is an EE type magnetic core, 9 is a coil bobbin, and 10 is a gap portion provided at the abutting portion of the center magnetic leg of the EE type magnetic core 8. 11 is between the wire rings and the magnetic core 8
, 12a and 12b are a part of the input winding, 13 is an output winding, and 14 is an interlayer insulating paper between the input windings 12a and 12b and the output winding 13. FIG. 4 is a cross-sectional view of the main part of the conventional foil wound converter transformer, showing the relationship between the leakage magnetic flux and the coil. In FIG. 4, 15 is the leakage flux, 12
a is a coil made of foil of the input winding.

The structure will be described with reference to FIGS. 3 and 4. Part of the input windings 12a, 12b and the conductor of the output winding 13 are copper foil or aluminum foil for increasing the coupling between the input winding and the output winding. A part 12a of the input winding is wound together with the interlayer insulating paper 14 from the lowermost layer of the coil bobbin 9, and the insulating paper 11 is wound thereon. Next, the output winding 13 is wound together with the interlayer insulating paper 14, and the insulating paper 11 is wound thereon. Further, a part 12b of the input winding is wound around it together with the interlayer insulating paper 14, and then the insulating paper 11 is wound in this order. Part of the input winding 12a, 12b is shown in FIG. They are connected as shown in the wiring diagram of b. Finally, the magnetic core 8 provided with the gap portion 10 between the EE type magnetic cores 8 is incorporated.

The operation of the foil wound converter transformer configured as described above will be described below.

The foil wound converter transformer used for switching power supplies is used at high frequencies of 20 KHz or higher. Then, in the converter transformer used in the flyback converter system, a ferrite core is used for the magnetic core, and a gap is provided in the ferrite core.

In such a converter transformer, when the foil wound converter transformer as shown in FIG. 4 is operating, the leakage magnetic flux 15 generated from the gap 10 provided between the magnetic cores 8
Interlinks with the part 12a of the input winding, and eddy current loss occurs in the conductor made of foil inside the part 12a of the input winding. This eddy current loss is greater near the gap 10 provided between the magnetic cores 8, and the wider the conductor is and the higher the frequency is, the greater the eddy current loss is, which deteriorates the efficiency of the foil wound converter transformer and generates heat. It was very big.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described conventional configuration, the leakage magnetic flux 15 generated from the gap 10 provided between the magnetic cores 8 is generated so as to be linked to a part of the input winding 12a, and thus the input winding Part 12a
Since an excessive eddy current loss is generated in the conductor of No. 2, there is a problem that a part of the input winding 12a generates a large amount of heat and the temperature becomes extremely high. In order to lower the temperature of the foil winding converter transformer, it is generally necessary to lower the DC resistance of the conductor that constitutes the input winding 12a. There is a restriction that it is necessary to use a different conductor or to use a magnetic core with less loss. Furthermore,
Although the magnetic core size of the converter transformer must be increased, the cost is high and the converter transformer is also large in size.

The present invention solves the above-mentioned problems of the conventional foil wound converter transformer, and it is necessary to use an expensive conductor material or magnetic core in order to reduce the influence of the leakage magnetic flux on the lowermost layer winding and also in terms of cost. The purpose is to provide a low-cost converter transformer.

Means for Solving the Problem In order to solve the problem, the converter transformer of the present invention has a conducting wire as a part of either one of an input winding and an output winding in the lowermost layer of a coil bobbin incorporated in a magnetic core. The winding part used is wound, and the remaining winding part and a conductor made of foil as the other winding are wound on the winding part.

With this configuration, while maintaining high coupling between the input and output windings, the leakage flux generated from the vicinity of the gap between the magnetic cores makes a coil turn per coil turn in the winding part made of the conducting wire wound in the lowest layer of the bobbin. The amount of leakage flux across the
Eddy current loss can be significantly reduced, and heat generation of the coil can be reduced. Also, the temperature of the entire converter transformer can be lowered.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a converter transformer according to an embodiment of the present invention. In FIG. 1, 1 is an EE type magnetic core,
Reference numeral 2 is a coil bobbin, and 3 is a gap portion provided at the abutting portion of the center magnetic leg of the EE type magnetic core 1. 4 is insulating paper between the loops and the magnetic core 3, 5a is a part of the input winding made of a conductor wire, 5b is a part of the input winding made of a conductor made of copper or aluminum foil, and 6 is also copper Alternatively, reference numeral 7 denotes an output winding made of a conductor made of aluminum foil, and reference numeral 7 denotes an interlayer insulating paper between the input windings 5a and 5b and the output winding 6. FIG. 2 is a sectional view of a main part of a converter transformer according to an embodiment of the present invention, showing a relationship between a leakage magnetic flux and a coil.

In FIG. 2, G is a leakage flux, and 5a is a part of the input winding. To explain the configuration in FIGS. 1 and 2, a conductor wire made of a copper wire, an aluminum wire, a litz wire, or the like is used as a conductor of a portion 5a of the input winding, and an output winding 6 and a portion 5b of the input winding 5b. Using a conductor made of copper or aluminum foil similar to the conventional one, first, a part 5a of the input winding is wound around the lowermost layer of the coil bobbin 2, and then the insulating paper 4 is wound thereon. Next, the output winding 6 is wound together with the interlayer insulating paper 7, and the insulating paper 4 is wound thereon. Further, wind a part 5b of the input winding together with the interlayer insulating paper 7, and
Next, a part of the input winding 5a, 5
b is connected as before. And finally EE
The magnetic core 1 in which the gap portion 3 is provided between the central magnetic legs of the die magnetic core 1 is incorporated.

The operation of the converter transformer configured as described above will be described below.

First, according to this embodiment, a part 5a of the input winding made of a wire with a small eddy current loss is formed in the lowermost layer of the coil bobbin 2 which is the closest to the gap 3 provided between the central magnetic legs of the EE type magnetic core 1. Since it is installed, the leakage flux G and the amount of leakage flux traversing one turn of the part 5a of the input winding are very small as shown in FIG. 2, and the eddy current loss can be greatly reduced. The heat generated in the coil of the part 5a of the input winding arranged in the lowermost layer becomes extremely small, and the temperature of the entire converter transformer can be lowered.

Although the embodiment has shown a configuration in which the input winding is divided into two, the same effect can be obtained by dividing the output winding 6 into two and forming a conductor in one of the two and a conductor made of foil.

As described above, according to the present invention, a winding portion in which a conducting wire is wound as either one of an input winding or an output winding on the lowermost layer of a coil bobbin incorporated in a magnetic core having a gap portion at a butt portion. Is placed on top of this, and the remaining winding part and the winding on which the conductor made of foil is wound are placed as the other winding, so that heat generated by the converter transformer is maintained while maintaining high coupling between the input and output windings. The work clamp can be lowered in temperature. In addition, we used high-cost materials such as those with a large cross-sectional area of the conductor made of foil used to reduce the temperature of the foil-wrap converter transformer, conductors made of foil with high conductivity, and magnetic cores with low loss. It is possible to realize an excellent converter transformer that is economical and economical in terms of cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the converter transformer of the present invention, FIG. 2 is an explanatory view showing the relationship between the leakage magnetic flux of the converter transformer of the present invention and a coil, and FIG. 3 is a conventional foil wound converter. Sectional view showing the structure of the transformer, No. 4
Fig. 5 is an explanatory diagram showing the relationship between the leakage magnetic flux and the coil, Fig. 5
a and b are connection diagrams showing an example of connection of coils of a converter transformer. 1 ... Magnetic core, 2 ... Coil bobbin, 3 ... Gap part,
4 ... Insulating paper, 5a, 5b ... Input winding, 6 ... Output winding,
7 ... Interlayer insulating paper.

Claims (1)

(57) [Scope of utility model registration request] 1. A winding part using a conductive wire as a part of either one of an input winding or an output winding is arranged at the lowermost layer of a coil bobbin incorporated in a magnetic core having a gap at a butt portion, and A converter transformer formed by winding a conductor made of foil on the remaining winding and the other winding.