JPH0834159B2 - Transformer with reactor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transformer having a built-in reactor.

[Prior Art] FIGS. 4 and 5 show, for example, noise flowing from a power source shown on page 114 of "Noise Technology of Electronic Circuits" (written by Yamazaki) issued by Ohm Co. on Dec. 10, 1982. The electric circuit diagram and structural drawing of the transformer which built in the reactor for reducing are shown. In the figure, a primary coil 18 and a secondary coil 19 surrounded by shield plates 16 and 17 are inserted into different legs of an iron core 15, respectively.

In the transformer having such a structure, noise that has entered from the terminals U-V of the primary coil 18 propagates to the secondary coil 19, but the primary and secondary coils are wound around separate legs of the iron core. , Leakage flux is likely to occur, that is, the reactor is equivalently built in, and the number decreases between the output terminals u and v. The shield plates 16 and 17 are electrostatic shield plates for the coils 18 and 19.

[Problems to be Solved by the Invention] Since the conventional transformer has the above-mentioned structure, high frequency noise is reduced, but when this is used as a commercial frequency power transformer, the coupling between the primary and secondary is poor. Therefore, the voltage drop becomes large and the voltage fluctuation rate becomes large,
There was a problem that it was not preferable for the load.

The present invention has been made to solve the above problems, and obtains a transformer with a reactor having a small voltage fluctuation rate as a commercial frequency power source transformer and having a capability of blocking it against high frequency noise. The purpose is to

[Means for solving the problem]

A transformer with a reactor according to the present invention includes a transformer iron core, a primary coil and a secondary coil wound around the iron core leg, and a core wound around the iron core leg with one end serving as a U-phase input terminal and the other end serving as one end. A U-phase side reactor coil connected to the U-phase of the next coil, and one end of which is wound around an iron core leg as a V-phase input terminal and the other end of which is connected to the V-phase of the primary coil and a U-phase side reactor. It is provided with a V-phase side reactor coil formed so as to have the same polarity with respect to the coil and the common input mode.

[Work]

Since the reactor in the present invention produces a large impedance for high frequencies, it reduces high frequency noise, and the impedance of the reactor is small for commercial frequencies, so the voltage drop due to it is small and therefore the voltage fluctuation rate is small. Become.

Example of Invention

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

FIG. 1 is an electric circuit diagram of the present invention. It has a primary coil 2 and a secondary coil 3 wound around an iron core 1, and converts a commercial frequency power source into a voltage. In the case of the inner iron type, the primary coil 2 is connected to both legs of the iron core 1 in series or in parallel, and the primary coil 2 is superposed on the primary coil 2 in order to close the coupling and reduce the voltage fluctuation rate. Turn 3 tickets. Coil 13 in FIG.
And 14 correspond to primary coils, and coils 21 and 22 are 2
It corresponds to the next coil 3. The coil 14 shown in FIG. 2 has the same structure as the coil 13, and is inserted in a leg different from the leg in which the coil 13 of the iron core 1 is inserted and is connected in series or in parallel with the coil 13. The coils 9, 10, 11, 12 perform the functions of the reactors 5 and 6 in FIG. 1, and are arranged at symmetrical positions (up and down in the example) with respect to the coils 13 and 14. The coils 9 to 12 are wound so as to have an inductance required to reduce high frequency noise, and are shielded. The output terminals u-v are omitted in the figure. Reference numerals 7 and 8 are electrostatic shield plates for the coils 5 and 6.

Common mode high-frequency noise that has entered from the input terminals U-V enters the coils 9 to 12, but is blocked by the reactor action of these coils. Coils 9-12 are coils
The effect is great because it is symmetrically arranged above and below so as to hold 13 and 14. At the commercial frequency, the impedance of the coils 9 to 12 is small and there is no voltage drop because of the polarity of in-phase winding.

Here, the reason why the high frequency noise in the common mode is reduced will be further described with reference to FIG.

Now, assume that the winding direction of each coil wound around the iron core 1 is as shown in FIG. First, V from the input terminal U
Assuming that a current I ₁ as shown by the solid line arrow flows as a normal current that does not include common mode frequency noise, a current of 1/2 ・ I ₁ flows in the coils 9 and 10, respectively, and The generated magnetic fluxes φ ₉ and φ ₁₀ are directed upward as shown by solid arrows. This current flows through the coil 13 through the coil 14 connected in series to it, and then in parallel to the coils 11 and 12 by 1/2. Then, since the magnetic fluxes φ ₁₁ and φ ₁₂ generated in the iron core leg by the currents flowing in the coils 11 and ₁₂ are directed upward as shown by solid arrows, the magnetic flux φ ₉ generated in the iron core leg by the current flowing in the coils 9 and 10 described above. , φ ₁₀ (upward) are canceled out, and the inductance becomes 0.

Further, the magnetic flux φ ₁₃ generated in the iron core leg by the current flowing in the coil 13 is directed downward as shown by the solid arrow, while the magnetic flux φ ₁₄ generated in the iron core leg by the current flowing in the coil 14 is
Are directed upward as indicated by solid arrows, they strengthen each other and act as the primary coil of a normal transformer.

Next, when a current I ₂ as shown by the broken line arrow containing the common mode high frequency noise flows from the input terminals U and V, 1/2 and I ₂ currents flow in the coils 9 and 10, respectively. The magnetic fluxes φ ₉ and φ ₁₀ generated in the iron core legs are directed upward as indicated by the dashed arrows, while the currents of 1/2 ・ I ₂ also flow in the coils 11 and 12, respectively, and the magnetic fluxes φ ₁₁ and φ generated in the iron core legs are generated. ₁₂ are directed downward as shown by the broken line arrow, strengthening each other, and have a predetermined inductance. This inductance acts as a common mode reactor, which reduces common mode high frequency noise.

In this way, by arranging the coils 9 and 10 or 11 and 12 symmetrically, the influence of the leakage flux of the coils 9 and 10 on the coil 13 or the influence of the leakage flux of the coils 11 and 12 on the coil 14 is reduced. And the effect will be greater.

Although the coils are provided on both legs in the above embodiment, only one coil may be provided. In this case, the reactor coil 9 may be connected on the U-phase side and 10 on the V-phase side.

In the case of FIG. 2, the number of coils is 9, and only 11 is 10,1.
2 may be omitted. Further, the coils 9 and 10 may not be wound on both ends of the coil 13 but may be wound on either side, and this is the same on the coil 14 side.

〔The invention's effect〕

As described above, according to the present invention, the voltage coil of the commercial frequency and the coil using the reactor for noise reduction are separated, and the coil for the reactor action is connected to the polarity for common mode noise elimination, so that the common mode noise is reduced. In addition, the commercial frequency power supply has an effect that a transformer with a reactor having a small voltage fluctuation rate and good characteristics can be obtained.

[Brief description of drawings]

1 is an electric circuit diagram showing an embodiment of a transformer with a reactor of the present invention, FIG. 2 is a structural diagram showing an embodiment of a transformer with a reactor of the present invention, and FIG. 3 is a diagram of a transformer with a reactor of the present invention. FIG. 4, FIG. 4 and FIG. 5 for explaining reduction of common mode high frequency noise in one embodiment.
The drawings are an electric circuit diagram and a structural diagram of a conventional transformer with a reactor. In the figure, 1 is an iron core, 2 is a primary coil, 3 is a secondary coil, 5 is a reactor, and 9 to 14 are coils. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A transformer iron core, a primary coil and a secondary coil wound around the iron core leg, and a primary coil and a secondary coil wound around the iron core leg, one end of which serves as a U-phase input terminal and the other end of which serves as the primary coil. And a U-phase side reactor coil connected to the U-phase, and one end of which is wound around the iron core leg as a V-phase input terminal and the other end is connected to the V-phase of the primary coil. A transformer with a reactor equipped with a V-phase side reactor coil formed to have the same polarity as the coil and the common mode input.