JPS6132506A - Transformer - Google Patents

Abstract

PURPOSE:To contrive accomplishment of miniaturization and reduction in production cost by a method wherein a transformer and an inductor are formed on a core. CONSTITUTION:The primary coil 7 and the secondary coil 8 of a transformer 2 are wound around the inner leg of the core of three-leg structure such as an EI-core and an EE-core, and split-wound coils 4a and 4b are wound on each outer leg. The split-wound coils have the same number of turns, and each split- wound coil is series-connected in such a manner that each of them has positive polarity as shown by dot mark in the diagram. When the transformer is constituted as above, the coils 7 and 8 on one side can be utilized as the coils for the transformer, and the coil 4 can be utilized as the coil for an inductor. Two sets of cores are constituted separately in the transformer heretofore in use, the now one set to core is sufficient, and the transformer can be made smaller in size.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to an improvement in the winding structure of a transformer used in an inverter, etc. [Prior art and its problems] After converting to high frequency voltage with inverter 1, transformer 2 increases it to an appropriate voltage [phase]
), then rectified by a rectifier 3, smoothed by an inductor 4 and a capacitor 5, and supplies DC power to a load 6. 7.8 shows the primary coil and secondary coil of the transformer 2, respectively.

Here, the inductor 4 has the role of a filter to prevent high-frequency current from flowing into the capacitor 5, but the inductor is large and has the disadvantage that it impedes miniaturization of the device and further increases cost. If this inductor is omitted, the above-mentioned drawbacks will be eliminated, but a high frequency current will now flow through the capacitor 5, causing the capacitor 5 to overheat, causing a practical problem.

If a capacitor with a very large capacity is used to prevent the capacitor 5 from overheating, there is a drawback that the inverter operation becomes unstable due to the rush current flowing into the capacitor when the power is turned on, and oscillation stops.

[Purpose of the invention]

In order to eliminate the above-mentioned drawbacks, the present invention aims to reduce size and cost by configuring inductors in transformers wound on separate cores on one core.

[Structure and operation of the invention]

FIG. 2 shows an embodiment of the present invention, and the reference numerals in the figure correspond to those shown in FIG.

The primary coil 7 and secondary coil 8 of the transformer 20 are wound around the inner leg of a three-legged core such as EI Cocoa and EE Cocoa, and the divided coils 4a and 4b are wound around each of the outer legs. The number of turns of the divided coils is equal, and each divided coil is connected in series so that the polarity becomes positive with respect to each other, as shown by the marks in the figure.

When the transformer is configured in this way, the magnetic flux generated by the current flowing through the primary coil 7 intersects with the secondary coil 8 as shown by the arrow in the figure, and induces a voltage in the secondary coil 8. In other words, the first-character coil 7 and the secondary coil 8 are magnetically coupled.
) Has the function of a lance.

On the other hand, the magnetic flux generated by the primary coil 7 is divided into two by the outer leg, intersects with the divided coils 4 & 4b, and induces a voltage between each divided coil. However, if the number of turns of the divided coils is too large and they are connected with positive polarity as shown in the figure, the direction of the magnetic flux that intersects with each divided coil will be reversed, so the induced voltages will cancel each other out and spread across the entire coil 4. As a result, no voltage is induced. Therefore, the primary coil T and the coil 4 are not magnetically coupled and do not function as a transformer. However, since each divided coil has its own inductance, the coil 4 can be regarded as two inductors connected in series, and has the role of a filter that cuts high frequencies as shown in FIG.

In Fig. 3, contrary to Fig. 2, the primary coil T (7
m+7b)? This is an example in which a secondary coil 8 (8m+8 b ) is provided and a coil 4 is provided on the inner leg.

In this case, the primary and secondary coils are wound in sections, and the coil 4 is not wound in sections. The operating principle is the same, so the description will be omitted.

〔Effect of the invention〕

As explained above, in the present invention, a coil is wound around each of the inner and outer legs of a tripod core whose magnetic path is divided into two,
In order to use one coil as a transformer coil and the other as an inductor coil, conventionally two sets of cores were used and configured separately, but now only one set of cores is needed, making the overall size smaller. Cost will be reduced.

[Brief explanation of the drawing]

FIG. 1 is an example of a circuit for explaining the transformer of the present invention, in which 1 is an inverter, 2 is a transformer, 3 is a diode, and 4 is an inverter.
is the inductor, 5 is the capacitor, 6 is the load, 7 is 1
The secondary coil 8 is a secondary coil. FIG. 2 is a diagram showing the structure of the transformer of the present invention, where 7 is a primary coil, 8 is a secondary coil, and 4 is a coil for an inductor. FIG. 3 shows another example of the present invention.

Claims (1)

[Claims] One or more coils are provided on each of the inner and outer legs of the tripod core, and the coils with the same number of turns provided on each outer leg are connected in series with positive polarity to form one coil. A transformer characterized in that one of the coils provided on the legs and the outer legs is used as a transformer coil, and the other is used as an inductor.