JP2558207B2 - Power saving device with voltage drop prevention - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power saving device such as a transformer having a function of automatically backing up a voltage when it drops below a certain voltage.

[0002]

2. Description of the Related Art Power saving devices such as two-phase three-wire transformers are:
As shown in FIG. 3, the main coils L ₁ , L ₂ and L ₅ , L ₆ wound around the single-phase inner iron core are wound in two circuit phases, and the cores are wound around the output terminals, respectively. Excitation coil L ₃ , L ₄
, L ₇ and L ₈ are connected in series, the midpoint of these exciting coils and the zero-phase terminal s are connected, and the output terminals of the single-turn main coils L ₂ and L ₆ are connected to terminals r and t of other phases. Connected.

In this case, the voltage taken out from the output terminals of the single-turn main coils L ₂ and L ₆ is surely lower than the input voltage, so that the power saving effect can be achieved.

For example, in the above circuit, if 100V is input between the R phase and the S phase, the voltage drops to 6V for the r phase and the s phase, and becomes 94V. Assuming that the load is constant (1Ω), I
₃ is 94A, the electric power is 8,836KW, and the power saving is 1,164KW from the input electric power of 10KW.

[0005]

However, in this power saving device, two exciting coils connected to the main coil are provided, and the exciting currents flowing through the exciting coils L ₃ , L ₄ and L ₇ , L ₈ are equal to each other. There are many loss currents inside the transformer because they are different. In addition, if there is a drop in the input voltage, the output voltage will drop more than expected, which may affect the load.

The present invention has been made in view of the above points, and provides a power-saving device that reduces the loss current inside the transformer and has a good voltage balance, and automatically when there is a drop in the input voltage. The present invention provides a power saving device with a voltage drop prevention that detects a voltage rise, increases the output voltage, and does not affect the load.

[0007]

SUMMARY OF THE INVENTION Therefore, according to the present invention, in a single-phase three-wire type or single-phase two-wire type single-winding coil type transformer, a plurality of main coils connected to input terminals are connected to a single-phase inner iron core. Circuit phase winding is performed, and an even number of four or more exciting coils wound around the core and connected in series with each other is connected between the ends of the main coils of each of these circuits. These exciting coils are composed of a plurality of sets of the exciting coils of the above two circuits in the order close to the end of the main coil of each circuit, and each output terminal of the transformer is connected to the main coil and the exciting coil of the above circuits. And the zero-phase input terminal and the output terminal are mutually connected.

Further, a separate voltage sensor is provided, the voltage sensor is connected to the input end of each of the main coils, and the voltage value detected by the voltage sensor drops or rises below a predetermined voltage at the output end of the voltage sensor. Then, each switch operates to provide two sets of thyristors, one of which is turned on and the other of which is turned off. One of these thyristors is connected between the two exciting coils of the set farthest from the end of the main coil of each circuit, and the other thyristor is connected between the two exciting coils of another appropriate set. However, by turning off one thyristor and turning on the other thyristor, it is possible to switch to a circuit that cuts one or more sets of exciting coils farther from the end of the main coil of each circuit than the other thyristor.

[0009]

[Operation] When a voltage is input to the input terminal of the transformer,
An exciting current flows through each of the plurality of exciting coils, and a certain voltage drops by the main coil. As a result, the voltage at the output terminal is lower than the input voltage by the fixed voltage. And now when the input voltage drops below a certain voltage,
This is detected by the voltage sensor, the switch is operated to turn on the other thyristor, the exciting coils of a part of the above-mentioned plural exciting coils are cut, and only the remaining exciting coils are energized to generate the exciting current. Flows. As a result, the width of the voltage drop in the main coil is small, and the voltage drop at the output terminal is suppressed.

When the input voltage is restored and becomes equal to or higher than a predetermined voltage, the voltage sensor detects the voltage, which activates the switch to turn on one thyristor, and the exciting currents to all the exciting coils of the plurality of sets. Flows again, and a certain amount of voltage drops again due to the main coil. In this case, the predetermined voltage value for detecting the drop of the input voltage below a predetermined voltage and turning on the other thyristor, and turning on the one thyristor for detecting the increase of the input voltage above the predetermined voltage It is made smaller than a predetermined voltage value to have hysteresis.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. A plurality of main coils L ₁ , L ₂ connected to input terminals R, T
2 and L ₅ and L ₆ are wound around the single-phase inner iron core 1 in two circuit phases, and between the ends of the main coils L ₂ and L _{6 of} these circuits, wound around the core 1 and connected in series with each other. A plurality of connected exciting coils L ₃ , L ₇ and L ₄ , L ₈ are connected. Further, the output terminals r and t of the transformer are connected between the main coil L ₂ and the exciting coil L _{3 of} each circuit, and between the main coil L ₆ and the exciting coil L ₇ , respectively, so that the zero phase input is made. The terminal S and the output terminal s are connected to each other.

Further, a voltage sensor 2 is provided, the voltage sensor 2 is connected to the input terminals of the main coils L ₁ and L ₅ , and the output terminals of the voltage sensor 2 are connected to the changeover switches 3 and 4.
The switches 3 and 4 are automatically switched when the voltage value detected by the voltage sensor 2 drops or rises below a predetermined voltage. Two sets of thyristors 5 and 6 are provided at the output ends of these switches 3 and 4, respectively. The input and output ends (cathode, anode) of these thyristors 5 are the above-mentioned exciting coils L ₄ and L _8.
And the gate is connected to the changeover switch 4. The input / output terminals (cathode, anode) of the thyristor 6 are connected between the exciting coils L ₃ and L _7, and the gate is connected to the changeover switch 3.

In the case of this embodiment, for example, the input terminals R, S
When a voltage of 106 V is applied in between, each of the main coils L ₁ , L ₂ ,
L _5, L ₆ and the exciting coil L _3, L _4, current flows through the L _7, L _8, the main coil _{L 1, L 2, L 5} , and 6V drop in L _6, an output terminal t, the inter-s The voltage is 100V. FIG. 1 shows this state. When the changeover switch 4 is turned on, the thyristor 5 is turned on, and an exciting current flows through all the exciting coils L ₃ , L ₄ , L ₇ , and L ₈ . In this case, the changeover switch 3 is off and the thyristor 6 is off.

When the input voltage drops below 97V for some reason, the voltage sensor 2 detects it and turns on the changeover switch 3 and turns off the changeover switch 4. Therefore, the thyristor 5 is turned off and the thyristor 6 is turned on. Therefore, no exciting current flows through the exciting coils L ₄ and L ₈ . The exciting current flows only in the exciting coils L ₃ and L ₇ . As a result, the main coils L ₁ , L ₂ , L ₅ , and L ₆ drop only 3V, and the voltage between the output terminals t and s becomes 94V.
In this way, when the input voltage drops to 97V, the output voltage becomes 9V.
Backup from 1V to 94V.

When the input voltage is restored and rises from 96 V, the voltage between the output terminals t and s also rises accordingly. When the input voltage reaches 99V, the voltage sensor 2 detects this and turns the changeover switch 3 off and the changeover switch 4 on. This allows thyristor 5
Turns on and the thyristor 6 turns off. Thus each exciting coil _{L 3, L 4, L 7} , L 8 and all the exciting current flows, the main coil _{L 1, L 2, L 5} , and 6V partial drop in L _6, an output terminal t, between s The voltage is 100V. FIG. 2 is a graph showing changes in the input voltage and the output voltage.

In this case, the predetermined voltage for backing up the output voltage due to the drop of the input voltage and the predetermined voltage for canceling the backup due to the rise of the input voltage are set to different levels, and hysteresis is provided, so that these switching can be smoothly performed. .

In the above-described embodiment, the single-phase three-wire system has been described.
When a similar voltage is input between the phases and a load is connected between the output terminals rt, the output voltage drops to 6 V as in the above embodiment, thereby saving power.

[0018]

According to the device of the present invention, the output voltage can be reliably reduced, thereby reducing power consumption and saving power. Further, when the input voltage drops below a predetermined voltage, this is automatically detected and the output voltage is backed up, so that the influence on the load is suppressed as much as possible.

Further, according to the present invention, the two-phase coil winding of the single-winding coil on the single-phase inner iron core causes a voltage inducing phenomenon between them inside the transformer, thereby improving the voltage balance. Further, in the present invention, since the exciting current flows between the R phase and the T phase, the exciting currents flowing through the plural sets of exciting coils are the same, and the loss current inside the transformer can be suppressed to a small level.

[Brief description of drawings]

FIG. 1 is a schematic configuration circuit diagram of an embodiment of the present invention.

FIG. 2 is a graph showing changes in input voltage and output voltage according to the device of the present invention.

FIG. 3 is a circuit diagram of a conventional power saving transformer.

[Explanation of symbols]

1 Single-phase inner iron core 2 Voltage sensor 5 Thyristor 6 Thyristor L ₁ Main coil L ₂ Main coil L ₅ Main coil L ₆ Main coil

Claims (1)

(57) [Claims] 1. In a single-phase three-wire or two-wire single-winding coil type transformer, a plurality of main coils connected to input terminals are wound around a single-phase inner iron core in two circuit phases, and the main of each of these circuits is wound. Between the ends of the coil, four or more even numbered excitation coils wound around the core and connected in series with each other are connected, and these excitation coils are arranged in the order of the above-mentioned 2 in order from the end of the main coil of each circuit. Each exciting coil of the circuit is configured as a set of a plurality of sets, each output terminal of the transformer is connected between the main coil and the exciting coil of each circuit, and the zero-phase input terminal and the output terminal are connected, Connect the input terminal of each main coil and the voltage sensor,
At the output end of this voltage sensor, two sets of thyristors, one of which is turned on and the other of which is turned off when the voltage value of the voltage sensor drops or rises below a predetermined voltage, are provided. Connect between the two exciting coils of the group farthest from the end, and another thyristor between the two exciting coils of the other appropriate set,
The voltage is characterized in that it can be switched to a circuit that cuts off one or more sets of exciting coils farther from the end of the main coil of each circuit than the other thyristor by turning off one thyristor and turning on the other thyristor. Power saving device with drop prevention.