JP3180184B2 - AC power supply device and impedance converter used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC power supply for supplying a constant current from a constant voltage source to a fluctuating load and supplying power from a constant current source to a load requiring a constant voltage. The present invention relates to an impedance converter used for the above.

[0002]

2. Description of the Related Art When a constant current is supplied to a fluctuating load, an AC constant current source as shown in FIG. 50606099). FIG. 4 is a circuit diagram showing a conventional AC constant current source, in which 61 indicates an AC power supply, 62 indicates a load, and 63 indicates a resonance circuit. The AC power supply 61 is connected to a load 62 via a resonance circuit 63. Resonant circuit 63 the inductor (inductance L) 63a, which is constituted by the capacitor (capacitance C) 63 b, by tuning the resonant frequency to the frequency of the AC power source 61, regardless of the impedance Z ₂ of the load 62 , and it is able to provide a constant current I ₂ to the load 62.

Now, the voltage between the input terminals 1 and 1 'of the resonance circuit 63, which is the connection point between the AC power supply 61 and the resonance circuit 63, is V ₁ , and the resonance circuit 63, which is the connection point between the resonance circuit 63 and the load 62, the output terminal 2, 2 'V ₂ the voltage between the input terminals 1
I ₁ the current through, the current supplied from the output terminal 2 to a load 62 when the I _2, the current I ₂ is represented by the following equation (1).

[0004]

(Equation 1)

In such a conventional AC constant current source, for example, when the output terminals 2 and 2 'are short-circuited,
Although the voltage V ₂ becomes zero and the power supplied to the load 62 becomes zero, the input current I ₁ of the input terminals 1 and 1 ′ does not become zero, and a wasteful current of I ₁ = V ₁ / ωL is generated. There was a problem that flow continued and efficiency was poor.

[0006] Further, as an apparatus using an AC constant current source,
A bulb lighting circuit as shown in FIG.
No. 5-119393). FIG. 5 is a circuit diagram showing a conventional lighting circuit for a light bulb. A large number of light bulbs 72 a to 72 d are connected in series to an AC constant current source 71. 73a
73d is a voltage limiter connected in parallel to each of the bulbs 72a to 72d. Even if one of the bulbs 72a to 72d, for example, the bulb 72a is disconnected, the other bulbs 72b to 72d are connected.
This is for limiting the voltage of the light bulb 72a so that the light 72d does not go out.

In such a bulb lighting circuit, each bulb 72a
To 72d are connected in series, so all the bulbs 72a
The same amount of current is supplied to .about.72d, and even if the length of the line becomes longer, each bulb is lit to the same brightness. However, even if the voltage limiters 73a to 73d are used as described above, if the bulb 72a is disconnected, a rise in the voltage of the terminal will cause a rise in the voltage of the AC constant current source 71, thereby increasing the burden.

When the light bulb 72a is disconnected, the light bulb 7
It is desirable that the terminal 2a be short-circuited. However, such a configuration has a problem that the circuit becomes complicated, and the use of an active element for short-circuiting causes a decrease in reliability. . Further, as a conventional AC constant current source, a conventionally known commercial constant current source is usually used. However, an AC constant current device is not widely used as a constant voltage device, and its structure is complicated and the number of parts is small. However, there was also a problem that the cost was high.

As a countermeasure against this, the present inventor has come up with the idea of combining an AC constant voltage source and an impedance converter as means for obtaining an AC constant current source. However, as shown in FIG. 6, a conventional impedance converter called an immittance converter is used, and has a structure using a line 80 corresponding to / 4 of the wavelength depending on the power supply frequency. The length of the line 80 corresponds to / 4 of the wavelength corresponding to the frequency of the power supply 81. If the characteristic impedance is Z ₀ , the voltages V ₁ and V _{1 at} the input terminals 1 and 1 ′ and the output terminals 2 and 2 ′ respectively. ₂ , the relationship between the currents I ₁ and I ₂ is expressed by equation (2).

[0010]

(Equation 2)

When a load 82 (impedance Z ₂ ) is connected to the output terminals 2 and 2 ′, the impedance Z ₁ viewed from the input terminals 1 and 1 ′ is expressed by the following equation (3).

[0012]

(Equation 3)

As is apparent from equation (3), impedance
Z₁Is the impedance Z of the load 82 _TwoProportional to the reciprocal of
You. Further, from the above equation (2), the current I_Two, I₁Is (4),
Each is represented by the equation (5).

[0014]

(Equation 4)

In such an immittance converter,
As is apparent from equation (4), the output current I _TwoIs the input voltage V
₁And the input current I₁Is out
Force voltage V _TwoThat is, the voltage V of the load 82_TwoAnd the load 8
2 impedance Z_TwoThe input current I is proportional to₁Flows
The Rukoto. Similarly, the output voltage V is calculated from the equations (4) and (5).
_TwoIs the input current I₁And the input voltage V₁Is the output current I
_TwoThat is, it is proportional to the supply current to the load 82. That is, AC
The constant voltage source is converted to an AC constant current source.

However, in such a conventional immittance converter, a line 8 having a length usually corresponding to 1/4 wavelength is used.
The application range of 0 is a frequency in which the length of the line 80 is several tens of cm or less, that is, a use range of 100 MHz or more, and the matching between the cable that normally connects the power supply and the load and the load, and the two characteristic impedances are different. Used for impedance matching of cables.

However, if such an immittance converter is used for an AC power supply having a frequency of several tens of kilohertz or less, which is advantageous for power transmission, a line length of several thousand m or more is required, and this is practical. There is a problem that is not. When supplying power from an AC constant current source,
There is a need for a device for converting an AC constant voltage source with a configuration as simple as possible.

The present invention has been made in view of such circumstances, and a first object is to combine an AC constant voltage source or an AC constant current source with an impedance converter to obtain an AC constant current source or an AC constant current source. The purpose is to make the voltage source easily configurable.

It is a second object of the present invention to reduce the size and weight by reducing the cost by making the impedance circuit a bridge-type four-terminal circuit.

[0020]

According to a first aspect of the present invention, there is provided an AC power supply apparatus comprising: an AC constant voltage source; and an impedance converter connected to the AC constant voltage source and configured by a bridge-type four-terminal circuit. The converter outputs an AC constant current proportional to the input voltage.

According to the first aspect of the present invention, the impedance converter outputs a current proportional to the input voltage by combining the AC constant voltage source and the impedance converter constituted by a bridge type four-terminal circuit. Therefore, by using an AC voltage source as a voltage source to make the input voltage constant, an AC constant current can be applied to the load.

An AC power supply according to a second aspect of the present invention includes an AC constant current source, and an impedance converter connected to the constant current source and configured by a bridge-type four-terminal circuit. It is characterized in that it outputs an AC constant voltage proportional to the current.

According to the second aspect of the present invention, the impedance converter outputs a voltage proportional to the input current by combining the AC constant current source and the impedance converter constituted by a bridge type four-terminal circuit. Thus, by using an AC constant current source as a current source to make the input current constant, an AC constant voltage can be applied to the load.

The impedance converter according to the third aspect of the present invention is constituted by a bridge-type four-terminal circuit, in which inductors are interposed between the corresponding input terminals and output terminals, respectively, and the corresponding diagonal diagonals are provided. A capacitor is interposed between the input terminal and the output terminal.

According to the third aspect of the present invention, a simple configuration for connecting two inductors and two capacitors in a bridge form is provided.
The impedance connected to the input terminal or output terminal
Since it can be converted to an impedance proportional to the reciprocal of its impedance when viewed from the output terminal or the input terminal, an AC constant voltage or an AC constant current can be obtained in combination with an AC constant current source or an AC constant voltage source, and the conversion into bidirectional It can be used.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. (Embodiment 1) FIG. 1 is a circuit diagram showing an AC constant current source to which an AC power supply device according to the present invention is applied. In the figure, 11 is an AC constant voltage source, 12 is a load, and 13 is an impedance converter. ing. The AC constant voltage source 11 is connected to a load 12 (impedance Z ₂ ) via an impedance converter 13. The impedance converter 13 is configured as a bridge-type four-terminal circuit as shown in FIG.
FIG. 2 is a circuit diagram of the impedance converter 13.
Reference numerals 4 and 15 denote inductors, and 16 and 17 denote capacitors.

That is, in the impedance converter 13, one input terminal 1 is bifurcated on the way, one is connected to the output terminal 2 via an inductor (inductance L ₁ ) 14, and the other is a capacitor (capacitance C _1). ) Is connected to the output terminal 2 ', the other input terminal 1' is bifurcated halfway, one is connected to the output terminal 2 'via an inductor (inductance L ₂ ) 15, and the other is connected to the output terminal 2'. It is connected to the output terminal 2 via a capacitor (capacitance C ₂ ).

The inductances of the two inductors 14 and 15 are equal (L ₁ = L ₂ ).
6, 17 have the same capacitance (C ₁ = C ₂ ), and the respective inductor 14 or 15 and the capacitor 16 or 17
Are made equal to the frequency of the alternating current applied to the input terminals 1, 1 '.

In the first embodiment, the voltage applied to the input terminals 1 and 1 'of the impedance converter 13 from the AC constant voltage source 11 is V ₁ , the input current is I ₁ , and the impedance conversion is performed. Output terminal 2,
The current supplied from the 2 'to the load 12 is I ₂ , and the voltage is V ₂
And a resonance angular frequency ω ｛= 1 / √ (L) of a resonance circuit including the inductor 14 or 15 and the capacitor 16 or 17.
C)｝ is equal to the angular frequency of the AC constant voltage source 11, and furthermore, the characteristic impedance Z ₀ = ωL = 1 / ωC = √ (L / C)
Then, the relationship of the above-described equation (2) is established. (2)
From the equations, the currents I ₂ and I ₁ are calculated as described in (4) and (5) above.
It is expressed by an equation.

In order to make the current I ₂ constant, the voltage V ₁ between the input terminals 1 and 1 ′ may be made constant from the equation (4), and by connecting the AC constant voltage source 11 to the impedance converter 13. and thus capable of supplying an alternating constant current to the impedance Z ₂ of the load 12. In other words, the impedance converter 13 as the Z ₁ = Z ₀ ² / Z ₂ Looking 'impedance Z ₂ of the load 12 connected to the other input terminal 1, 1' one terminal 2,2 from the impedance Z has a function of converting the impedance Z ₁ is proportional to _the reciprocal.

When the impedance converter 13 is viewed from the output terminals 2 and 2 ′, the inductor 1 is connected to the AC constant voltage source 11.
4 and capacitor 17 and inductor 15 and capacitor 1
6 forms a parallel resonance circuit, the impedance becomes infinite, and the internal impedance of the power supply acts as an infinite AC constant current source.

Referring to the equation (5), when the impedance Z ₂ = 0 of the load 2, that is, the output terminals 2 and
2 'is short-circuited, the output voltage V ₂ = 0, and when viewed from the input terminals 1 and 1', the inductor 14 and the capacitor 16,
Further, the inductor 15 and the capacitor 17 form a parallel resonance circuit, the impedance Z ₁ becomes infinite, and the input current I ₁ = 0. Note Z ₁ represents an impedance when viewed impedance converter 13 from the input terminal 1, 1 '.

When an AC constant current source is combined with an impedance converter composed of a bridge type four-terminal circuit, the impedance converter has a proportional relationship between the input current and the output voltage. An AC constant voltage can be applied from the heater to the load.

(Embodiment 2) FIG. 3 is a circuit diagram showing an AC power supply device according to the present invention and a lighting circuit of a bulb using an impedance converter used for the AC power supply device. In the figure, 21 is an AC constant voltage source, 22 is a power transmitting unit impedance converter, 23 is a power supply line, 24 to 27 are power receiving unit impedance converters, 2
Numerals 8 to 31 indicate light bulbs. The power transmission unit impedance converter 22 includes inductors 22 a and 22 b and a capacitor 22.
c and 22d are connected as a four-terminal circuit in a bridge form.

The AC constant voltage source 21 is connected to an input terminal of the power transmitting unit impedance converter 22. The constant voltage from the AC constant voltage source 21 is converted into an AC constant current and supplied to the power supply line 23. . Feed line 23, usually has a large induced inductance, counteracting its voltage drop at the series capacitor C _0. The AC constant current supplied from the power supply line 23 is converted into a constant voltage by each of the power receiving unit impedance converters 24 to 27, and each of the bulbs 28 to 31 is turned on at a constant voltage. The magnitude of the current flowing through the power supply line 23 is determined only by the fundamental component of the AC constant voltage source and the characteristic impedance of the power transmission unit impedance converter 22.

On the other hand, in the power receiving unit, the constant current of the power supply line is converted to a constant voltage through the power receiving unit impedance converters 24 to 27, so that the individual bulbs are turned on under the same conditions as when turned on by the constant voltage source. You. The power supply line and the power receiving unit impedance converter input terminal can be insulated by electromagnetic coupling such as a transformer. Voltage V ₂₁ ~V ₂₄ is the feed line 23
And the characteristic impedance of the power receiving unit impedance converters 24 to 27, it is possible to light bulbs having different voltage ratings. Input voltage V ₁₁ ~V ₁₄ of the power receiving section impedance transformer 24-27 output current I
₁ is proportional to ~I _4, the magnitude I ₀ of the alternating current constant-voltage source is determined by the sum of the voltage drop of their total voltage and the power supply line.

The light bulb 28 is connected directly to the power supply line 23 with the power receiving unit impedance converter 24 to act as an AC constant voltage source, and is turned on using the power as a power source. The bulb 29 receives power through a transformer T loosely coupled to the feeder. Resonant capacitor C ₁₂ connected to the secondary side of the transformer T is for increasing the power receiving efficiency.

The light bulb 30 and the light bulb 31 can be connected in parallel at the same rated voltage because the output of the power receiving unit impedance converter 26 is a constant voltage source. The output of the power receiving unit impedance converter 27 is rectified by a diode bridge to drive the DC motor 32. Whatever type of load is mixed with the bulb load and fed from the power supply line together, there is no interference between them and there is no hindrance to the lighting operation.

Now, for example, when the first light bulb 28 is disconnected, the current I ₁ becomes 0, so that V ₁₁ also becomes 0. Therefore, the value of the current I of the power supply line 23 does not change and does not affect the brightness of the other bulbs at all. In the second embodiment, the impedance converters 24 to 2
The use of 7 avoids the influence of the voltage drop of the power supply line 23 in serial lighting, and eliminates the disadvantage that all the bulbs are turned off when one bulb is disconnected. Further, by changing the voltage of the AC constant voltage source, it is possible to simultaneously change the brightness of all the light bulbs.

[0040]

According to the first aspect of the present invention, the output voltage of the constant voltage source is fixed by the impedance converter by combining the AC voltage source and the impedance converter constituted by a bridge type four-terminal circuit. It is converted to current without loss, and an inexpensive AC constant current source can be obtained.

According to the second aspect of the present invention, by combining an AC constant current source and an impedance converter composed of a bridge type four-terminal circuit, the output current of the constant current source is fixed by the impedance converter. It is converted to voltage without loss, and an inexpensive AC constant voltage source can be obtained.

According to the third aspect of the invention, the inductor and the capacitor are connected in a bridge form, and the resonance frequency of the resonance circuit including the inductor and the capacitor is made equal to the frequency of the AC power supply applied to the input terminal, so that noise is reduced. An AC constant voltage source or an AC constant current source is easily obtained with small waveform distortion and high reliability.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment according to the present invention.

FIG. 2 is a circuit diagram of an impedance converter used in the first embodiment.

FIG. 3 is a circuit diagram showing a lighting circuit of a light bulb to which an AC power supply device according to the present invention and a circuit of an impedance converter used therein are applied.

FIG. 4 is a circuit diagram showing a conventional AC constant current source.

FIG. 5 is a circuit diagram showing a lighting circuit of a conventional light bulb.

FIG. 6 is a circuit diagram of a quarter-wave impedance converter.

[Explanation of symbols]

 11 AC constant voltage source 12 Load 13 Impedance converter 14, 15 Inductor 16, 17 Capacitor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05F 1/12

Claims (3)

(57) [Claims] 1. An AC constant voltage source, and an impedance converter connected to the constant voltage source and configured by a bridge type four-terminal circuit, and outputting an AC constant current proportional to the input voltage from the impedance converter. An AC power supply device characterized in that: 2. An AC constant current source, and an impedance converter connected to the constant current source and configured by a four-terminal circuit of a bridge type, and outputting an AC constant voltage proportional to the input current from the impedance converter. An AC power supply device characterized in that: 3. A bridge type four-terminal circuit, wherein inductors are interposed between corresponding input terminals and output terminals, respectively, and between corresponding diagonal input terminals and output terminals. Impedance converters characterized by each having a capacitor interposed.