JPH0767336A - Voltage-stabilizing transformer - Google Patents

Abstract

PURPOSE:To provide a small, low-cost voltage-stabilizing transformer of improved reliability. CONSTITUTION:An AC voltage obtained from a secondary coil 2 of a transformer is compared with a predetermined reference voltage by a voltage comparator 3. Based on the comparison result obtained from the voltage comparator 3, taps 5 provided in a primary coil 1 of the transformer are switched to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage setting and stabilizing transformer for stably converting an input AC voltage into a different AC voltage and outputting the AC voltage.

[0002]

2. Description of the Related Art There are constant voltage transformer (CVT) type and inverter type voltage setting and stabilizing transformers that convert constant AC voltage and output even if the input AC voltage changes.

FIG. 2 is a circuit diagram showing an outline of the CVT system. The CVT type is a resonance coil 13 in which a primary coil 11 having an input terminal, a secondary coil 12 having an output terminal, and a capacitor 14 are connected with an iron core 10 interposed therebetween.
Are magnetically coupled to each other. The frequency of the resonance circuit formed by the resonance coil 13 and the capacitor 14 is matched with the power supply frequency supplied to the primary coil 11, and is constantly excited by the primary coil 11. Therefore, even if the voltage supplied to the primary coil 11 fluctuates to some extent, the voltage generated in the secondary coil 12 can be kept substantially constant only by changing the energy distribution of the resonance circuit. .

FIG. 3 is a block diagram showing an outline of the inverter system. In this inverter type, a rectifier 21 having an input terminal and an inverter 22 having an output terminal connected thereto are arranged. The operation of such a configuration will be described. The AC voltage input from the input terminal is once converted into a DC voltage by the rectifier 21. Then, this DC voltage is converted into a constant AC voltage by the inverter 22 and output from the output terminal.

[0005]

The CVT system described above has the drawbacks that it has a large size and is expensive because it is equipped with a capacitor and a resonance coil, and that it can handle only one frequency. Further, since the resonance development is used, there is a drawback that a beat noise is emitted.

The inverter type has a drawback that the inverter itself is expensive and the circuit is complicated, so that there is concern about reliability.

The present invention has been made under the circumstances described above, and an object of the present invention is to be small and inexpensive.
It is to provide a highly reliable voltage setting stabilizing transformer that does not have frequency dependence.

[0008]

The present invention relates to a voltage setting and stabilizing transformer which stably converts an input AC voltage into different AC voltages via a primary coil and a secondary coil and outputs the AC voltage. The above object of the invention is to compare the converted AC voltage with a predetermined reference voltage, a voltage comparison means, a tap that is provided in the primary coil and that can change the number of windings of the primary coil, and the voltage comparison. Switching means for switching the tap based on the comparison result from the means.

[0009]

In the present invention, the converted AC voltage is compared with the reference voltage, and the deviation is corrected by automatically switching the taps, so that a constant AC voltage can always be output. it can.

[0010]

1 is a block diagram showing an example of a voltage setting stabilizing transformer of the present invention. A primary coil 1 having an input terminal and a tap 5 and a secondary coil 2 having an output terminal are arranged with an iron core 6 in between. The secondary coil 2 is connected to a voltage comparator 3 that compares the converted AC voltage with a predetermined reference voltage RV and outputs the deviation. A switching circuit 4 is connected to the primary coil 1 to switch the tap 5 provided in the primary coil 1 based on the deviation signal from the voltage comparator 3. Regarding the switching timing of the tap 5 in the switching circuit 4, a 0-cross method is adopted in order to prevent the occurrence of noise and instantaneous interruption.
Further, as the switching means, for example, a thyristor or a triac is used.

The operation of the above arrangement will be described. AC voltage input from the input terminal
Conversion is performed through the iron core 6 and the secondary coil 2, and the AC voltage and the reference voltage are compared by the voltage comparator 3 to obtain the deviation. Then, the tap 5 included in the primary coil 1 is appropriately switched by the switching circuit 4 based on the deviation from the voltage comparator 3 so that the AC voltage output from the output terminal becomes constant. Even if the input AC voltage fluctuates due to such an operation, the fluctuation can be instantaneously changed to the corrected number of windings of the primary coil 1, so that the AC voltage should always be converted and output. You can

Although the switching circuit 4 and the tap 5 are provided on the side of the primary coil 1 in the above-described embodiment, the same effect can be obtained even if they are provided on the side of the secondary coil 2. Further, if the switching circuit 4 or the like is provided on the side where the alternating voltage is high, the operating current can be reduced, which is effective.

[0013]

As described above, according to the voltage setting and stabilizing transformer of the present invention, it is possible to obtain a constant output voltage with only a simple circuit configuration, so that the size and cost can be reduced and the output side can be obtained. It is possible to secure a constant voltage even if the load changes. Further, since it does not depend on the frequency, the reliability can be significantly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a voltage setting stabilizing transformer of the present invention.

FIG. 2 is a circuit diagram showing a first example of a conventional voltage setting and stabilizing transformer.

FIG. 3 is a block diagram showing a second example of a conventional voltage setting stabilizing transformer.

[Explanation of symbols]

 1,11 Primary coil 2,12 Secondary coil 3 Voltage comparator 4 Switching circuit 5 Tap 6,10 Iron core 13 Resonance coil 14 Capacitor 21 Rectifier 22 Inverter

Claims (1)

[Claims] 1. A voltage setting and stabilizing transformer that stably converts an input AC voltage into different AC voltages via a primary coil and a secondary coil and outputs the AC voltage, and compares the converted AC voltage with a predetermined reference voltage. Voltage comparison means, a tap provided on the primary coil for changing the number of windings of the primary coil, and a switching means for switching the tap based on a comparison result from the voltage comparison means. A voltage setting stabilizing transformer.