JP3035728B2 - 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 a means for reducing a receiving voltage to an appropriate voltage, there are a method using an autotransformer and a method using a combination of a plurality of sets of coils. The method using an autotransformer is to output a plurality of taps on the secondary side, switch the taps with a switch, and change the voltage drop according to the impedance ratio between the primary side and the secondary side. As a method of using a plurality of sets of coils, there is a technique described in JP-A-6-178462. This is because 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 is reduced by the main coil. This causes the voltage at the output terminal to drop by a fixed voltage from the input voltage. The voltage was controlled by reading the voltage with a sensor, controlling a thyristor or a magnet contactor that determines the combination of the exciting coils with a sensor switch, and changing the combination to change the amount of descent.

[0003]

However, in both methods, the voltage drop is not continuous but intermittent.
Power saving efficiency was not enough. In addition, since the switching operation is performed by an electromagnetic switch or thyristor, there is a problem that the contacts and elements of the switch are deteriorated. Further, in order to solve such a problem, as shown in FIG. 8, a reactor 5 'is inserted in series with an electric circuit, and the impedance of the reactor is changed by a DC exciting current I1, so that an electromagnetic switch, a thyristor, etc. A so-called reactor method for controlling the amount of voltage drop without using a switch is proposed. However, in the case of this method, the voltage waveform is greatly distorted due to the characteristics of the load, and as a result, there is a problem that the reactor generates a loud noise. Therefore, the present invention provides a power-saving device with improved durability by using the above-described reactor method to increase power-saving efficiency, eliminate the use of switches such as electromagnetic switches and thyristors, and provide a power-saving device with less voltage distortion. Is to do.

[0004]

In order to solve the above problems, a power saving device according to the present invention is connected to a single-phase three-wire circuit having two voltage lines and one neutral line, and is connected to an input voltage. And a reactor having a ladder-shaped core in which five winding portions are arranged in parallel are installed between a voltage line and a neutral line, respectively. , Central third
The winding portion is wound with a DC coil for excitation, and two sets of second and fourth winding portions adjacent to the third winding portion or the first and fifth winding portions outside the third winding portion. One of the sets is a series winding section, in which two coils connected in series between the voltage line input and output are wound, and the other set of winding sections is a shunt winding section. Wherein two coils connected in series are wound between the output side of the voltage line and the neutral line, and the adjacent first and second coils are wound.
The winding portions or the adjacent fourth and fifth winding portions are
The series winding and the shunt winding are connected to each other so as to form a forward magnetic field and to form a reverse magnetic field in the central third winding portion. Connected to a power supply and a current control unit for controlling the current, the current control unit is connected to a voltage detection unit for detecting a voltage between a voltage line and a neutral line, and an output voltage is generated by an exciting current of a DC coil. Configured to control.

In a single-phase two-wire circuit comprising two power lines, a configuration between one of the two voltage lines and the neutral line of the two voltage lines of the single-phase three-wire circuit is provided. In this case, a set of a reactor, a DC power supply, a current control unit, and a voltage detection unit may be used.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described in detail with reference to the drawings. FIG. 1 shows a first embodiment, in which a reactor 5 having a DC power supply 3 and a current control unit 4 and a voltage detection unit are connected to a single-phase three-wire circuit in a neutral line N.
Is set as a target on both voltage lines X and Y sides. The reactor 5 includes a DC coil L1 and AC coils L2, L3,
L4 and L5 are configured as one set, 1 is a single-phase three-wire power supply, and 2 is a load.

[0007] The DC coil L1 is connected to the current control unit 4 and the DC power supply 6, and a DC exciting current I1 controlled by the current control unit 4 flows from the DC power supply 6. This exciting current I
1 is a voltage detector 3 connected between the neutral line and the output voltage line.
The current control unit 4 receives the output voltage V2 detected by the control unit 4 and outputs it. The output voltage V2 is feedback-controlled. Hereinafter, since it is symmetrical around the neutral line N,
Only the X side will be described.

FIG. 2 shows the structure of the reactor 5. The iron core is a three-legged core composed of three three-legged cores T1, T2, T3, and five winding portions M1, M2,. have. The five winding portions are firstly connected to a third winding portion M at the center.
3 is wound with a DC coil L1, and two adjacent winding portions M2 and M4 are wound with AC coils L2 and L3 connected in series between X-side input / output voltage lines. A series winding portion is formed, and the end thereof is used as the output X 'of the voltage line.
Further, AC coils L4 and L5 connected from the neutral line N to the output voltage line X 'are wound around the two winding portions M1 and M5 on the outer side in parallel with each other when viewed from the power supply side. Road winding part is formed. The neutral line N is common to the input side and the output side.

[0009] Each coil is wound so as to have a magnetic field direction as shown in FIG. FIG. 3A shows one polarity of the magnetic field formed by the AC coils L2 to L5, and the first winding unit M1 and the second winding unit M2 adjacent to each other or the fourth winding unit M2.
The winding M4 and the fifth winding M5 form a forward magnetic field, and the third winding M3 at the center is wound so as to form mutually opposite magnetic fields and cancel each other. FIG. 3B shows a DC magnetic field generated by the DC coil L1.

Next, the operation of the power saving device configured as described above will be described. In the AC coils L2, L3 and the DC coil L1, the AC magnetic flux generated in the iron core T2 is canceled by the central third winding part M3, so that the AC magnetic flux is applied to the DC coil L1 wound around the third winding part M3. Have a substantially zero mutual inductance. Also, in this iron core T2,
When the amount of DC magnetic flux by the DC coil L1 increases, the iron core T2
, The impedance of the AC coils L2 and L3 decreases.

The relationship between the input voltage V1 and the output voltage V2 is such that the effective component of the voltage generated by the reactor 5 is VT, and the invalid component is V.
If L, the relationship shown in the vector diagram of FIG. 4A is obtained, and the relationship shown in Expression 1 is obtained. From this equation, the coil L
2, when the impedance of L3 decreases and approaches 0, the voltage VL approaches 0 and the output voltage V2 approaches the input voltage V1.

(Equation 1)

In the flow of the power saving control, the output voltage V2 is detected by the voltage detector 3, and the exciting current I1 of the DC coil L1 is feedback-controlled. This control reduces the exciting current I1 when the output voltage V2 is higher than the set value, increases the voltage drop, and when the output voltage V2 is lower than the set value,
The exciting current I1 is increased to reduce the voltage drop. As described above, since the supply voltage to the load 2 can be controlled by changing the exciting current I1 of the DC coil L1, a switch such as a magnet or a thyristor is not required. Then, continuous voltage control is possible, the voltage can always be reduced to a voltage appropriate for the load, and high power saving efficiency can be obtained.

Next, the reason why distortion is suppressed in this embodiment will be described. In the power saving device of FIG. 1, for example, when the input voltage V1 = 105 V, the output voltage = 97 V, and the voltage drop width ΔV = 8 V, the effective component of the reactor 5 is approximately VT = 4 V from the vector diagram of FIG. The invalid component is VL = 15V. FIG. 6B shows a vector diagram of each voltage of the power saving device of FIG. In this figure, VL 'is a voltage generated by the reactor 5'. in this case,
Assuming that the input voltage V1 = 105V and the output voltage V2 = 97V, the generated voltage of the reactor 5 'is approximately VL' = 30V.

Here, the instantaneous value of the input voltage is v1, the instantaneous value of the output voltage is v2, the instantaneous value of the voltage drop in the reactor is vL, the load current is i, and the inductance of the reactor is L.
Then, they have the following relationship. v2 = v1−vL = v1−jω · L · i (1) Assuming that i = constant and ω = 2πf = constant, vL = K · L (K is a constant), and vL and L are proportional I do.

Therefore, the relationship between the ineffective component VL of the generated voltage of the reactor 5 shown in FIG. 1 and the reactor generated voltage VL 'of the reactor 5' shown in FIG. 7 is VL '= 30V = 2VL, so that the reactor 5' shown in FIG. And the inductance L 'of FIG.
L ′ = 2L (2) from the expressions (1) and (2), v2 = v1−jω · L · i in FIG. 1 and v2 = v1−jω · 2 in FIG. L · i, and the waveform distortion factor in FIG. 1 is reduced by half in FIG. 1 compared to FIG. 7, and the distortion is improved.

Further, looking at each order, the fundamental frequency is f, the harmonic order is n, and the nth harmonic current is in.
Then, the output voltage v2 can be expressed as in Equation 2.

(Equation 2) The distortion rate dist% V2 is as shown in Expression 3.

(Equation 3) From the equation of the distortion rate of Equation 3, the inductance L in FIG. 1 is reduced to half the value of FIG. 7, and the distortion rate is improved. Thus, according to the present invention, since the waveform distortion of the voltage is suppressed, it is possible to suppress the growling noise of the reactor.

Next, a second embodiment will be described.
FIG. 5 shows a circuit configuration of a second embodiment of a single-phase three-wire system, and FIG. 6 shows a detailed configuration of the reactor 15 of FIG. The difference from the first embodiment lies in the arrangement of the coils of the reactor, in which the set of the coils L2 and L3 of the series winding and the set of the coils L4 and L5 of the shunt winding are interchanged. ing. The same components as those of the first embodiment are denoted by the same reference numerals.

The winding direction of each coil of the reactor 15 is such that the adjacent first winding portion M1 and second winding portion M2 or the fourth winding portion M4 and the fifth winding portion M5 are forward magnetic fields. As in the first embodiment, the third winding M3 at the center is wound in the magnetic field direction shown in FIG.

Next, the operation of the second embodiment will be described. In the AC coils L4 and L5 and the DC coil L1, the interaction between the coils in the iron core T2 is the same as in the first embodiment, so that the magnetic fluxes of the coils L4 and L5 cancel each other, so that the mutual inductance to the DC coil L1 is almost zero. Becomes
When the amount of DC magnetic flux by the DC coil L1 increases, the magnetic permeability at both ends of the iron core T2 decreases, and the AC coils L4, L
5 becomes smaller. Also, when the magnetic flux decreases, the magnetic permeability at both ends of the iron core T2 increases, and the AC coil L4,
The impedance of L5 increases.

Therefore, the input voltage V1 and the output voltage V
In the relational expression 2, the value of the voltage VL changes, and the output voltage can be stepped down. However, in this case, the control flow is different from that of the first embodiment, and when the output voltage V2 is higher than the set value, the exciting current I1 is increased to increase the voltage drop amount.
If it is lower than the set value, the exciting current I1 is reduced to reduce the amount of voltage drop. In the second embodiment, the same effects as those of the first embodiment are obtained, and voltage distortion can be suppressed.

FIG. 7 shows an example of the embodiment of the present invention in the case of a single-phase two-wire circuit. FIG. 7 shows the voltage line X and the middle line of the power saving device of the single-phase three-wire circuit of FIG. The configuration with the sex line N is applied. The same applies when a configuration between the voltage line Y and the neutral line N is applied, and 1 'is a single-phase two-wire power supply and 2' is a load. Further, the configuration between the voltage line X and the neutral line N or the configuration between the voltage line Y and the neutral line N of the second embodiment can be applied to the single-phase two-wire electric circuit as it is. The same effect can be obtained by performing power saving control similar to that of the single-phase three-wire circuit.

Although the output voltage control method of the present invention performs feedback control for detecting the output voltage and controlling the voltage, feedforward control for detecting the input voltage and controlling the output voltage may be employed.

[0023]

As described above, since the present invention controls the voltage drop by the DC exciting current, there is no need for a switching unit such as an electromagnetic switch or a thyristor, and there is no fear of deterioration. Further, since continuous control can be performed by the DC excitation current, the voltage can always be controlled to be appropriate for the load, and high power saving efficiency can be obtained. Further, since the waveform distortion of the voltage can be improved by providing the reactor between the neutral wire and the voltage wire, it is possible to suppress the growling noise of the reactor.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a first embodiment of a power saving device in a single-phase three-wire circuit of the present invention.

FIG. 2 is a configuration diagram of one set of the reactor of FIG. 1;

3 shows the direction of the magnetic field of the reactor shown in FIG. 2,
(A) shows one polarity of the AC magnetic field, and (b) shows the DC magnetic field.

4A and 4B show vector diagrams of input / output voltages, FIG. 4A is a vector diagram of FIG. 1, and FIG. 4B is a vector diagram of FIG.

FIG. 5 shows a second embodiment of the power-saving device for a single-phase three-wire circuit according to the present invention.
FIG. 3 is a circuit configuration diagram of the embodiment.

FIG. 6 is a configuration diagram of one set of the reactor of FIG. 5;

FIG. 7 is a circuit configuration diagram of an embodiment of a power saving device of a single-phase two-wire electric circuit according to the present invention.

FIG. 8 is an explanatory circuit diagram of a conventional power saving device using a reactor method.

[Explanation of symbols]

3 ··· Voltage detection unit, 4 ··· Current control unit, 5,15 ··· Reactor, 6 ··· DC power supply, L1 ··· DC coil, L2
... L5 ... AC coil, T1-T3 ... Iron, I1 ...
Excitation current (DC excitation current), M1 ··· First winding, M2
.. A second winding part, M3 a third winding part, M4 a fourth winding part, M5 a fifth winding part.

Claims (2)

(57) [Claims] 1. A power saving device connected to a single-phase three-wire circuit provided with two voltage lines and one neutral line, for stepping down an input voltage and outputting the voltage, and comprising five winding portions A reactor having a ladder-shaped iron core arranged in parallel is installed between the voltage wire and the neutral wire, and a DC coil for excitation is wound around the third winding portion at the center among the winding portions. One of the two sets of the second and fourth winding portions adjacent to the third winding portion or the first and fifth winding portions outside the second and fourth winding portions is a series winding portion. Wherein two coils connected in series between the voltage line input and output are wound, and the other set of windings is a shunt winding,
Two coils connected in series between the output side of the voltage wire and the neutral wire are wound, and the adjacent first and second winding portions or the adjacent fourth and fifth winding portions are The series winding and the shunt winding are connected to each other so as to form a forward magnetic field and to form mutually opposite magnetic fields in the central third winding section, and supply an exciting current to the DC coil. It is connected to a DC power supply and a current control unit for controlling the current, the current control unit is connected to a voltage detection unit for detecting a voltage between a voltage line and a neutral line, and the output voltage is determined by an exciting current of a DC coil. To control the power saving device. 2. A power-saving device connected to a single-phase two-wire electric circuit composed of two power lines, for stepping down an input voltage and outputting the same, comprising a ladder-shaped core having five winding portions arranged in parallel. Is disposed between the electric paths, and a DC coil for excitation is wound around the third winding portion at the center among the winding portions, and the second and fourth windings adjacent to the third winding portion are provided. One of the two winding units, the wire unit or the first and fifth winding units outside the wire unit, is a series winding unit and is connected in series between one power line input and output. The other set of windings is a shunt winding, and two coils connected in series between the output side of one power line and the other power line are wound. And the adjacent first and second winding portions or the adjacent fourth and fifth winding portions respectively form a forward magnetic field,
The series winding and the shunt winding are connected to each other so as to form mutually opposite magnetic fields in the central third winding portion, and the DC coil is connected to a DC power supply for supplying an exciting current and a current for controlling the current. A power saving device connected to a control unit, wherein the current control unit is connected to a voltage detection unit that detects a voltage between both power lines, and controls an output voltage by an exciting current of a DC coil.