JPH08126318A - Power transformer device - Google Patents

Abstract

PURPOSE: To obtain a larger output from a power transformer device which half-wave rectifies the voltage across the secondary winding of a power transformer by suppressing the magnetic saturation of a core caused by the current of the secondary winding of the transformaer. CONSTITUTION: A primary winding 1, a secondary winding 2, and a ternary winding 3 of the power transformer of a power transformer device are wound around a core 4. An AC voltage from a power source 5 is applied across the primary winding 1 and a DC voltage is outputted by half-wave rectification on the voltage across the secondary winding 2 by means of a diode 6. An electric current 7 flows through the winding 2 in the direction and a magnetic field 8 is generated in the core 4 in the one direction. Therefore, the magnetic saturation of the core 4 by the magnetic field 8 is prevented by making an electric current 13 flow through the ternary winding 3 by applying the DC voltage across the winding 3 through a choke coil 12 and generating a magnetic field 14 in the direction in which the magnetic field offsets the magnetic field 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply transformer device for half-wave rectifying the voltage of a secondary winding and outputting a DC voltage.

[0002]

2. Description of the Related Art A power transformer that half-wave rectifies a voltage induced in a secondary winding and outputs a DC voltage has a current flowing in only one direction in the secondary winding. Compared with the case of wave rectification, the core is likely to be in a magnetic saturation state, and the DC voltage that can be taken out is limited. To prevent this magnetic saturation, increase the magnetic capacity of the core, that is,
The core size must be increased if the same core material is used.

[0003]

SUMMARY OF THE INVENTION In view of the above points, the present invention is to prevent magnetic saturation without increasing the core size and to allow a larger DC voltage to be taken out.

[0004]

In order to solve the above-mentioned problems, the present invention applies a direct current voltage to a primary winding of a power transformer by half-wave rectifying the voltage induced in the secondary winding. The present invention provides a power transformer device in which a tertiary winding is provided in the power transformer, and a current in a direction opposite to the current of the secondary winding is applied from a DC power source.

[0005]

With the above-described structure, in the power transformer device according to the present invention, the bias current of the core resulting from half-wave rectification of the voltage of the secondary winding of the power transformer is applied to the DC current applied to the tertiary winding The core is not magnetically saturated, and a larger DC voltage can be taken out.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power transformer device according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of the essential parts of an embodiment of a power transformer device according to the present invention. In the figure, 1 is a primary winding of a power transformer, 2 is a secondary winding, and 3 is a tertiary winding, and these windings are wound around a core 4. An AC voltage from a power supply 5 is applied to the primary winding 1, and the secondary voltage induced in the secondary winding 2 is half-wave rectified by a diode 6 to output a DC voltage. Due to this half-wave rectification, a current flows in the secondary winding 2 only in the direction of the arrow 7, and thereby a magnetic field 8 in the direction of the arrow is generated in the core 4.

When there is no tertiary winding 3 or no voltage is applied to the tertiary winding 3, the magnetic field 8 is in one direction, and its average value is, for example, + a shown in FIG. When the magnetic capacity of the core 4 with respect to the direct current taken out from the secondary winding 2 is insufficient (the core is small), the core 4 is in a magnetic saturation state as shown by a dotted line in the figure, and no further output can be obtained.

Therefore, for example, the voltage from the AC power supply 9 (which may be the same as the power supply 5) is rectified by the diode 10 and smoothed by the capacitor 11, and this DC is supplied to the tertiary winding 3 via the blocking ring 12. Apply so that it flows in the direction of arrow 13,
A magnetic field 14 in the direction opposite to the magnetic field 8 due to is generated in the core 4. For the magnitude of the magnetic field 14, the number of turns of the tertiary winding 3 and the current value are appropriately set, and the magnitude of the magnetic field 14 is set to this magnetic field 14.
To cancel the magnetic field 8. The blocking wire 12 is inserted between the DC power supply and the AC voltage induced in the tertiary winding 3 so as not to be short-circuited by the capacitor 11 or the like.

As a result, as shown in FIG. 2B, the magnetic field generated in the core 4 is close to the balance of the strengths in the + direction and the-direction, magnetic saturation is less likely to occur, and a larger secondary output can be obtained. become able to. Although the DC power supply applied to the tertiary winding 3 is used by rectifying the voltage of the AC power supply 9 in the above description, a part of the DC output rectified by the diode 6 or another DC power supply is used. You may do it. Also, by increasing the number of turns of the tertiary winding 3, the required magnetic field 14 is generated with a small direct current.

[0010]

As described above, according to the power transformer device of the present invention, the core demagnetization due to the half-wave rectification of the voltage of the secondary winding of the power transformer causes the magnetic field due to the current of the tertiary winding. Since the core is not magnetically saturated, a large DC voltage can be taken out, and if the output is the same, the core size can be reduced, so that the material cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of essential parts of an embodiment of a power transformer device according to the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the power transformer device according to the present invention.

[Explanation of symbols]

 1 primary winding 2 secondary winding 3 tertiary winding 4 core 5 AC power supply 6 diode for half-wave rectification 7 direction of current in secondary winding 13 direction of current in tertiary winding

Claims (5)

[Claims] 1. A power supply transformer having a tertiary winding, wherein an AC voltage is applied to a primary winding of the power transformer and a voltage induced in the secondary winding is half-wave rectified to output a DC voltage. A power transformer device in which a current in a direction opposite to the current of the secondary winding is applied from a DC power source. 2. The power transformer apparatus according to claim 1, wherein the voltage of the DC power supply is set to a value that cancels the core demagnetization due to the current of the secondary winding by the magnetic field generated in the tertiary winding. . 3. The power transformer device according to claim 1, wherein the tertiary winding is provided with an intermediate tap, and the tap is switched according to the current of the secondary winding. 4. The method according to claim 1, wherein a part of the direct current taken out through the secondary winding is applied to the tertiary winding through a closed loop. Power transformer equipment. 5. An AC voltage applied to the primary winding is rectified to the tertiary winding, and is applied via a required obstruction coil, claim 1, claim 2 or claim 3. Power transformer equipment.