JP3104013B2 - Power saving device - 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 that saves power consumption by reducing the received voltage to an appropriate voltage when the received voltage is high.

[0002]

2. Description of the Related Art As such conventional power saving devices, there are a tap switching type and a saturation transformer type. In the tap switching type, as shown in the principle diagram of FIG. 4, a plurality of tap switching switches 23 are provided on the primary winding 21 of the transformer 20, and these are connected to the power supply 1 to serve as a power input section. . The secondary winding 22 has a reduced polarity with respect to the power supply, and has one end connected to the primary winding and the other end connected to the load 11. The voltage was adjusted by changing the turns ratio and changing the output voltage by switching the primary tap changeover switch 23 using an electromagnetic contactor or a thyristor.

As shown in the basic principle diagram of FIG. 5, a transformer 24 has excitation windings 27a and 27b in addition to a primary winding 25 and a secondary winding 26, and further includes a reactor 2
8 is connected to the primary winding 25 in series. Then, a DC current is passed from the exciting current control circuit 29 to the exciting windings 27a and 27b to control the magnetic flux of the transformer 24 and adjust the voltage.

[0004]

However, in the case of FIG. 4 , since the voltage is adjusted by using the tap, there are problems that noise at the time of switching affects the output voltage and that the contacts are easily broken. In addition, since the voltage cannot be adjusted without permission, efficient power saving control cannot be performed. Also,
In the case of FIG. 5 , since the voltage is adjusted by controlling the magnetic flux, the voltage can be steplessly controlled and the reliability against the failure is high, but the transformer 2 is connected by the reactor 28 connected in series.
Therefore, there is a problem in that it is difficult to produce a high-capacity transformer because the primary current of No. 4 is limited, and when the control width of the voltage is too large, the output current waveform is distorted due to the shortage of the primary current. Therefore, an object of the present invention is to provide a power saving device capable of adjusting a voltage steplessly without switching taps, and further suppressing waveform distortion of an output voltage.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is a power saving device for adjusting power supply by adjusting an AC voltage using a transformer and a saturable reactor.
A secondary winding and a saturable reactor are connected in series, both ends of which are connected in series to form a power input section.
The secondary winding is connected to the power supply side of the primary winding at one end in the direction of depolarization, the other end and the power supply side of the saturable reactor form an output unit, and the transformer is a DC excitation winding. The saturable reactor has two sets of DC exciting windings, while the exciting current of the DC exciting winding can be controlled by an exciting current control circuit connected to a voltage detection circuit that detects an output voltage. One DC excitation winding is connected to change the excitation current in proportion to the secondary voltage of the transformer, the other DC excitation winding is connected to change the excitation current in proportion to the load current,
An AC voltage is controlled by an exciting current of a DC exciting winding of the transformer.

The saturable reactor has a set of DC exciting windings, and the DC exciting windings are provided by a second exciting current control circuit connected to the voltage detecting circuit separately from the exciting current control circuit. The exciting current of the line can be controlled, and the AC voltage can be controlled by the exciting current of the DC exciting winding of the transformer.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a circuit block diagram showing an example of the embodiment, and the same components as those in the conventional example of FIGS. 4 and 5 are denoted by the same reference numerals. In FIG. 1, a primary winding L1 of a transformer 2 and a main winding L5 of a saturable reactor 3 are connected in series, and both ends are connected to a power supply 1. The secondary winding L2 of the transformer 2 has one end connected to the power supply side of the primary winding and the other end connected to the load 11 so as to have a reduced polarity with respect to the power supply.

The transformer 2 further comprises two exciting windings L3, L4
The excitation windings L3 and L4 are connected and connected to an excitation current control circuit 4, and are wound so as to excite an iron core of the transformer 2. The exciting current control circuit 4 supplies the load 11
Connected to a voltage detection circuit 10 for detecting an output voltage to
The excitation current of the excitation windings L3 and L4 is controlled in response to the detection voltage.

The saturable reactor 3 includes a main winding L5 and 4
It has the excitation windings L6, L7, L8, L9. The exciting windings L6 and L7 are connected to form a first set of exciting windings, both ends of which are connected via the rectifier 6 to the secondary winding L of the transformer 2.
2, and a DC exciting current proportional to the induced voltage of the secondary winding L2 flows. Excitation winding L
8, L9 are similarly connected to form a second set of excitation windings, both ends of which are connected via a rectifier 7 to a current transformer (CT) 5 for detecting a load current, and a DC excitation proportional to the load current. An electric current flows. Reference numerals 8 and 9 are smoothing capacitors for smoothing the rectified voltage.

The structure of the transformer 2 and the saturable reactor 3 is as shown in FIG. FIG. 2A is a structural diagram of the transformer 2, where the primary winding L 1 and the secondary winding L 2 are three-legged iron cores 1.
The excitation windings L3 and L4 are wound around the right and left cores, respectively. The exciting windings L3 and L4 are connected as shown by the dotted lines in the figure.

FIG. 2B shows the structure of the saturable reactor 3, in which a main winding L5 is wound around a central core of a three-leg iron core 17b, and a first set of excitation windings L6 and L7 is They are wound around the left and right cores, respectively, and are connected as shown by the dotted lines in the figure. Similarly, the second excitation winding sets L8 and L9 are similarly wound around the left and right cores, respectively, and are connected as indicated by dotted lines. In this embodiment, the primary winding L1 of the transformer 2 and the main winding L5 of the saturable reactor 3 have the same impedance, and the primary to secondary turns ratio L1: L
2 is set to 100: 10.

Next, the operation of this circuit will be described. First,
When 100 V is output from the power supply 1 and no current is supplied to the excitation windings L3 and L4 of the transformer 2, the transformer 2 operates as a normal transformer, so that the number of turns on the secondary side is reduced. A proportional voltage is induced. The voltage induced on the secondary side is converted to DC by the rectifier 6 and the smoothing capacitor 8 and flows as DC current into the excitation windings L6 and L7 of the saturable reactor 3. When this DC current has a magnitude sufficient to magnetically saturate the iron core 17b, the main winding L5 of the saturable reactor 3 loses impedance due to DC excitation, so that almost no voltage is applied, and the voltage of 100 V Will be applied to the primary side of the transformer 2. Therefore, in this case, the secondary voltage of the transformer 2 is −
10V, and the voltage supplied to the load side is (100 V
-10V) of 90V.

Next, with the power supply voltage kept at 100 V, a DC current is supplied from the exciting current control circuit 4 to the exciting winding L of the transformer 2.
3, energize L4. Then, since the iron core 17a of the transformer 2 is DC-magnetized, the coupling between the primary winding and the secondary winding is lost, and no voltage is induced on the secondary side during saturation. Therefore, in this case, the primary side voltage of 100 V is applied to the load as it is. When the iron core of the transformer 2 is DC-magnetized, the primary winding L1 of the transformer 2 loses its impedance, but the impedance of the saturable reactor 3 connected in series to the primary winding is changed by the transformer 2 Since the voltage on the secondary side becomes zero, the power supply voltage is applied to the saturable reactor 3, and no overcurrent flows to the primary side.

Next, when the DC exciting current from the exciting current control circuit 4 is gradually reduced, the secondary voltage of the transformer 2 gradually increases, and the primary impedance of the transformer 2 is simultaneously increased. Increases, and the impedance of the saturable reactor 3 decreases. Therefore, the voltage supplied to the load side gradually decreases from 100 V, and reaches 90 V when the DC excitation is stopped in the transformer 2.

As described above, since the impedance of the primary winding L1 of the transformer 2 and the impedance of the main winding L5 of the saturable reactor 3 exclusively increase and decrease, if the load current is constant, the total impedance always becomes constant. It is controlled to be constant. Further, the load current is constantly monitored by the current transformer 5, the change in the load current is converted into a DC current by the rectifier 7 and the smoothing capacitor 9, and the load is changed to the second excitation winding set L 8, L 9 of the saturable reactor 3. The energization finely adjusts the impedance of the main winding L5 of the saturable reactor 3 to complement the change in the primary impedance of the transformer 2 due to a change in load current.

As described above, by controlling the exciting current by the exciting current control circuit 4, it becomes possible to continuously change the voltage on the load side. Can be controlled so that the output voltage becomes equal to the output voltage. In addition, since the exciting current corresponding to the load current can always be supplied to the primary side of the transformer 2 by the action of the saturable reactor 3, an output voltage with less voltage distortion can be supplied.

Next, another embodiment of the present invention will be described with reference to FIG. In FIG. 3, the configuration of the transformer 12 is the same as that of the transformer 2 of FIG. 1, but the saturable reactor 13 is different, and the transformer 12 includes a main winding L5 and two excitation windings L10 and L11. The first exciting current control circuit 1 connected to the transformer 12 is connected to the exciting windings L10 and L11.
4 is connected to a second exciting current control circuit 15 which is separate from the circuit 4. Then, the first exciting current control circuit 1 of the transformer 12
4 and second exciting current control circuit 1 of saturable reactor 13
5 is connected to a voltage detection circuit 16 for detecting an output voltage, and each of them controls a DC excitation current by a load voltage. Also, as in FIG. 1, the turns ratio of the transformer 12 is set to 100: 10, and the primary winding L1 and the main winding L5 of the saturable reactor 13 have the same impedance.

With this configuration, the impedance control of the saturable reactor 13 is performed by the exciting current control circuit 15.
Thus, the number of excitation windings can be reduced by one, and a current transformer and a rectifier are not required.

In the above embodiment, the turns ratio of the transformer is set to 100: 10, or the impedance ratio between the transformer and the saturable reactor is set to 1: 1. However, the present invention is not limited to this value. It can be changed according to. In addition, the present invention is not limited to the above-described embodiment, and may be implemented by appropriately changing the structure and configuration of the transformer and the saturable reactor without departing from the spirit of the present invention.

[0020]

As described above in detail, according to the present invention, since the voltage can be adjusted steplessly without switching the tap, there is no risk of deterioration of the contacts and the like, and efficient power saving control can be achieved. It is possible. Further, since the load current and the load voltage are detected and the impedance of the saturable reactor is adjusted, an output voltage with little voltage distortion can be supplied.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram illustrating an example of an embodiment of the present invention.

FIGS. 2A and 2B show specific structures of the transformer and the saturable reactor of FIG. 1, wherein FIG. 2A is a structural diagram of the transformer and FIG. 2B is a structural diagram of the saturable reactor.

FIG. 3 is a circuit block diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a conventional power saving device, and is a basic principle diagram of a tap switching type.

FIG. 5 is a diagram showing a conventional power saving device, and is a basic principle diagram of a saturation transformer type.

[Explanation of symbols]

1. Power supply, 2. Transformer, 3. Saturable reactor,
4. Excitation current control circuit, 5 Current transformer, 10 Voltage detection circuit, 11 Load, 12 Transformer, 13 Saturable reactor, 14 First excitation current control circuit , 1
5 second excitation current control circuit, 16 voltage detection circuit, L1 primary winding, L2 secondary winding, L3, L4
..Exciting winding, L5..Main winding, L6, L7, L8, L
9, L10, L11 ... exciting winding.

Claims (2)

(57) [Claims] 1. A power saving device for controlling power by adjusting an AC voltage using a transformer and a saturable reactor, wherein a primary winding of the transformer and a saturable reactor are connected in series, and the series connection is performed. Both ends constitute a power input section, and the secondary winding of the transformer is connected to the power supply side of the primary winding at one end in a direction of decreasing polarity, and the other end and the power supply side of the saturable reactor are output. And the transformer further comprises a DC excitation winding,
While the exciting current of the DC exciting winding can be controlled by an exciting current control circuit connected to a voltage detecting circuit for detecting an output voltage, the saturable reactor has two sets of DC exciting windings, The DC exciting winding changes the exciting current in proportion to the secondary voltage of the transformer, and the other DC exciting winding is connected to change the exciting current in proportion to the load current. A power saving device that controls the AC voltage by the exciting current of the winding. 2. A power-saving device for controlling an AC voltage by a transformer and a saturable reactor to save power, wherein a primary winding of the transformer and a saturable reactor are connected in series, and the series connection is performed. Both ends constitute a power input section, and the secondary winding of the transformer is connected to the power supply side of the primary winding at one end in a direction of decreasing polarity, and the other end and the power supply side of the saturable reactor are output. And the transformer further comprises a DC excitation winding,
While a first exciting current control circuit connected to a voltage detection circuit for detecting an output voltage enables control of an exciting current of the DC exciting winding, the saturable reactor has a set of DC exciting windings. , A second connected to the voltage detection circuit.
A power saving device, wherein the exciting current of the DC exciting winding can be controlled by the exciting current control circuit of the above, and the AC voltage is controlled by the exciting current of the DC exciting winding of the transformer.