JP3094217B2 - 6-phase multi-dimensional discharge device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of connecting an output voltage obtained by using a plurality of three-phase to twelve-phase AC conversion power supplies for converting three-phase AC to twelve-phase AC to discharge electrodes arranged three-dimensionally. Further, the present invention relates to a technical field of freely controlling a three-dimensional structure of a high-temperature, high-density arc plasma generated in a discharge space surrounded by discharge electrodes.

[0002]

2. Description of the Related Art In recent years, as the behavior of electric discharge has become evident due to the progress of plasma physics, arc plasma is used not only for cutting and welding of metals but also for melting of waste materials, and industrial application fields are rapidly increasing. It is expanding to.
Particularly, in the treatment of industrial waste containing harmful substances such as heavy metals and dioxins, there is a very high possibility that the waste can be rendered harmless by high-temperature treatment, and is attracting attention as one of the future treatment techniques.

As described above, the thermal application of arc plasma is as follows.
Although high temperature and high processing speed are greatly expected, existing arc plasma generators have a narrow high-temperature area and are not suitable for processing a large amount of waste. That is, 12,000 at the center of the arc plasma.
(° C.), it is known that the temperature drops sharply to 500 (° C.) just a few centimeters away from the center. Generally, the high temperature region by arc plasma is a very limited range.

[0004] For this reason, development of a new plasma generator for efficiently melting waste has been promoted.
However, in an example of a waste treatment plant that is actually used, in order to efficiently conduct heat transfer, the apparatus is rotated so that the inputted waste is concentrated at a predetermined place,
Countermeasures have been taken, such as turning the plasma generator in a pestle shape.

[0005] Under such circumstances, the emergence of a larger plasma generator is expected. However, the cost of the power supply increases significantly as the size of the DC system is increased. It is clear that. The reason for this is that the DC method requires an AC / DC converter for temporarily converting AC to DC. Thus, the emergence of an AC-type plasma generator that does not require an AC / DC converter has come to be expected.

[0006] In general, a plasma generator using an AC system uses a three-phase AC as a power source. In 1992, Sato introduced an AC power supply device for generating a multi-electrode arc discharge using a plurality of carbon electrodes, and an arc discharge device therefor (Japanese Patent Laid-Open No. 4-347577, 1992).
This device combines three sets of commercial three-phase AC,
The arc discharge region is expanded by simultaneously generating a plurality of arc discharges. In this device, a power source from a commercial three-phase alternating current is branched into three systems, each of which is connected to three electrodes. However, it cannot solve the problem of generating an arc by three-phase alternating current, that is, the drawback that stable sustained discharge cannot be obtained by stopping the discharge when the current value becomes zero. To compensate for this, the auxiliary electrode is arranged at the center of the discharge space.
Further, the power supplied to the discharge electrode is controlled by the thyristor, and the power supply and the control circuit are complicated.

The patent of Tsujino (Japanese Patent No. 2618813,199)
In the 12-phase AC power supply device in 7), the above-mentioned problem of Sato is improved and a stable discharge is obtained. However, each of the embodiments requires a three-phase transformer for obtaining two types of six-phase AC groups from a commercial three-phase AC power supply (in the Tsujino patent, this is called a star connection power supply unit).
A 12-phase AC is obtained from this three-phase transformer by further connecting to a star connection group and a delta connection group. Since the 12-phase AC is not directly obtained from the commercial three-phase AC power supply, a total of 15 single-phase A transformer is required and the circuit configuration is complicated.

[0008] Further, in order to actually apply it in industry,
It is necessary to scale up the capacity of the transformer, the discharge current, the thickness of the discharge electrode, etc. according to the purpose. However, in the method of Tsujino, the transformer of the three-phase power supply is replaced by the capacity of the 12-phase AC output transformer. It is necessary to increase the size in accordance with the sum of the above, which is a fatal disadvantage in practical use. In addition, the shape of the arrangement of the discharge electrodes is arranged in a regular 12 pyramid shape,
Although arc plasma is concentrated, it is impossible to expand the discharge region three-dimensionally because of its structure.

In 1994, Matsuura and Tsujino, including the present inventor,
Tago, Taniguchi, et al. Devised a power supply device that obtains six-phase AC from commercial three-phase AC, and are making prototypes and experiments of a new type of six-electrode arc discharge device ("Experiment of arc plasma generation by six-phase AC"). "Transactions of the Institute of Electrical Engineers of Japan, Vol. 114, No. 1, 1994). The arc discharge by this device is different from the arc discharge by Sato, and a stable continuous discharge is obtained. Since this power supply circuit can be realized with six single-phase transformers, it has a feature that the system configuration is simplified.

However, this is a basic experiment, and there are the following problems in realizing practical industrial applications.
That is, since the discharge space is planar, heat exchange with the substance charged into the discharge space is not sufficiently performed, and the ratio of passing untreated material is large. Also, the discharge space surrounded by the discharge electrode tip is as narrow as about 7 cm to 10 cm in diameter,
The discharge space is insufficient for continuously processing a large amount of processed materials. Therefore, in order to more effectively utilize the ultra-high temperature of the arc plasma and realize an efficient high-temperature processing system, it is necessary to expand the discharge space and at the same time three-dimensionally expand the discharge space.

[0011]

[Problems to be Solved by the Invention] Three-phase using a transformer
In the six-phase conversion method, the connection relationship between the primary winding and the secondary winding is a star-star (Y-Y) connection and a delta-star (Δ
-Y) connection. Since there is a phase difference of 30 degrees in the secondary side output voltage between these two connection methods, the present invention takes advantage of this characteristic to completely eliminate devices such as phase-advancing capacitors, interphase reactors, and thyristors. An object of the present invention is to provide a 12-phase AC power supply that can directly convert a 3-phase AC to a 12-phase AC and output the same using only one type of transformer without using it.

Another technical problem of the present invention is to realize stable discharge using a 12-phase AC power supply.

[0013] Still another technical problem of the present invention is:
An object of the present invention is to realize a light-weight, small-sized, and efficient 12-phase AC conversion power supply by enabling a phase conversion from three-phase AC directly to 12-phase AC by using six single-phase transformers having intermediate taps.

Further, another technical problem of the present invention is that
By multiplexing using a plurality of the above-mentioned three-phase to twelve-phase AC conversion power supplies, the efficiency of a melt processing device or a chemical reaction accelerator utilizing an ultra-high temperature generated by electric discharge is improved. An object of the present invention is to realize a multi-dimensional discharge space having a three-dimensional plasma structure.

[0015]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a primary coil of a transformer is connected in a star connection, and a winding ratio of a primary side and a secondary side is 1: 1.
1. Three single-phase transformers having an intermediate tap in the secondary coil at 1 and a transformer This problem has been solved by adopting three single-phase transformers each having an intermediate tap in the secondary coil, and technical means for interconnecting them with the intermediate tap as a neutral point.

Further, the present invention provides a method for controlling the output derived from the 12-phase AC conversion power supply obtained by the above technical means.
The first, third, fifth, seventh,
The ninth and eleventh are connected to the discharge electrodes arranged at the vertices of the upper regular hexagon, and the second, fourth, sixth, eighth, tenth, and tenth order are connected in that order. The twelfth problem is solved by connecting the twelfth discharge electrodes to the discharge electrodes arranged at the apexes of the lower regular hexagon having an angle difference of 30 degrees from the upper stage to obtain a multidimensional discharge.

Further, according to the present invention, the structure of the three-dimensional plasma region can be changed by controlling the value of the current flowing through the twelve electrodes derived from the twelve-phase AC conversion power source obtained by the above technical means. The above-mentioned problem of being able to be solved was solved. In addition, the degree of coupling between the primary coil and the secondary coil of the transformer is changed by an electric (including a mechanical) method to freely control the output current.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 1 is a circuit diagram of conversion from three-phase AC to 12-phase AC,
FIG. 2 is a vector diagram showing the relationship between three-phase, six-phase, and twelve-phase alternating current, FIG. 3 is a connection diagram of a power supply according to an embodiment of the present invention, and FIG. FIG. 5 is a second embodiment of a six-phase multi-dimensional discharge device using a 12-phase AC power supply, and FIG. 6 is a diagram illustrating a high-temperature plasma region generated by the six-phase multi-dimensional discharge device. Explanatory diagram showing that the discharge path is shortened,
FIG. 7 is an explanatory diagram of a three-dimensional arrangement of electrodes.

First, a 12-phase AC conversion power supply will be described with reference to FIGS. 1 to 3, and then a 6-phase multiplex three-dimensional discharge device using a 12-phase AC conversion power supply with reference to FIGS. 4 to 7. I will explain.

"Conversion circuit from 3-phase to 12-phase AC" FIG. 1
As shown in (1), this power supply device mainly includes two components, that is, a delta connection portion and a star connection portion. Hereinafter, each component and its connection method will be described.

In the delta connection section, the primaries of three single-phase transformers having intermediate taps are delta-connected and connected to a commercial three-phase input. Similarly, in the star connection section, the primary sides of three single-phase transformers having intermediate taps are star-connected and connected to the commercial three-phase input as before. The point to be noted here is that the intermediate taps on the secondary side of the delta connection and the star connection are all connected to each other to be a neutral point. Also, the magnitude of the secondary output voltage obtained by delta connection is
Secondary output voltage obtained by star connection

"Vector diagram showing the relationship between three-phase, six-phase, and twelve-phase alternating currents" As shown in FIG. 2A, the primary coil-secondary coil combination of the transformer is connected to the primary side of the star-star connection. a vector of _voltage, expressed as _{V x, V y, V z} . The voltages at the output terminals of the secondary coil when this is converted into six phases are V _x ′, V _y ′, and V _z ′. Similarly, phase _{V x} of the vector _{', V y', V z} ' and 180 ° output voltages of different secondary coil _V x _", V y", it is necessary to star connect _{V z} ". As shown in FIG. 2B, the combination of the primary coil and the secondary coil of the transformer is
The vector of the primary voltage of the delta-star connection is expressed as V
_x δ, V _y δ, and V _z δ. When this is converted into six phases, the voltage of the output terminal of the secondary coil is V _x δ ', V
_y δ ′ and V _z δ ′. Similarly, if the phase of the vector is V
_{x δ ', V y δ'} , V z δ ' with 180 ° different from the secondary coil of the output voltage _{V x δ ", V y δ} ", it is necessary to star connect _{V z} [delta] ". Thus 2 obtained
By connecting the neutral points of the two 6-phase alternating current secondary coils to each other (combining the vectors), a 12-phase alternating voltage can be obtained. Here, in order to equalize the magnitudes of the vectors of the 12-phase alternating current, with respect to the turns ratio 1 of the star-star connected transformer, It is. The 12-phase alternating currents obtained in this manner are all sinusoidal alternating currents having the same amplitude and a different phase by 30 °.

[Transformer Connection Diagram of Embodiment] As shown in FIG. 3, the three-phase to twelve-phase AC converter includes intermediate taps N ₁ and N ₁ .
A transformer T ₁ having ₂ , N ₃ , N ₄ , N ₅ , N ₆ ,
It is composed of T ₂ , T ₃ , T ₄ , T ₅ , and T ₆ . Transformer T
_{For 1} , T ₂ and T ₃ (primary coils are star-connected), the primary terminals R, S and T are connected to a three-phase AC power supply. Primary terminals R, S, T for transformers T ₄ , T ₅ , T ₆ (primary coils are delta connected)
To a three-phase AC power supply. Intermediate taps N ₁ , N ₂ , N
₃ , N ₄ , N ₅ , N ₆ are connected to each other and connected to the neutral point of the secondary coil of the _six transformers (T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T ₆ ). I do. Secondary outputs O ₂ , O of transformer T _1
8 is connected to the discharge electrodes O ₂ and O ₈ in FIG. Similarly, the secondary outputs O ₄ and O ₁₀ of the transformer T ₂ are connected to the discharge electrodes O ₄ and O ₁₀ in FIG. The secondary outputs O ₆ and O ₁₂ of the transformer T ₃ are connected to the discharge electrodes O ₆ and O ₁₂ of FIG. The secondary outputs O ₁ , O ₇ of the transformer T ₄ are connected to the discharge electrodes O ₁ , O ₇ of FIG. The secondary outputs O ₃ and O ₉ of the transformer T ₅ are connected to the discharge electrodes O ₃ and O ₉ of FIG. The secondary outputs O ₅ and O ₁₁ of the transformer T ₆ are connected to the discharge electrodes O in FIG.
_5, respectively coupled to _{O 11.} In order to realize a practical three-phase to twelve-phase AC converter, six single-phase transformers having intermediate taps may be combined, or two three-phase transformers may be combined.

[First Embodiment of Six-Phase Multiple Stereoscopic Discharge] As shown in FIG. 4, 12 discharge electrodes (for example, carbon)
2 sets each (O ₁ , O ₃ , O ₅ , O ₇ , O ₉ , O ₁₁ )
And (O ₂ , O ₄ , O ₆ , O ₈ , O ₁₀ , O ₁₂ ), and the respective sets are arranged horizontally on the same circumference in the upper and lower rows. In this case, 6 arranged at the vertex of the regular hexagon
The discharge electrodes of this book are arranged in the same manner in the upper and lower rows (referred to as double parallel electrodes). In this case, the distance between the upper and lower planes is set substantially equal to the distance D between the electrodes. Due to such a three-dimensional electrode arrangement, a mutual discharge occurs between the upper six electrodes and the lower six electrodes, resulting in a multi-dimensional discharge.

[Second Embodiment of Six-Phase Multiple Stereoscopic Discharge] As shown in FIG. 5, 12 discharge electrodes (for example, carbon)
2 sets each (O ₁ , O ₃ , O ₅ , O ₇ , O ₉ , O ₁₁ )
And (O ₂ , O ₄ , O ₆ , O ₈ , O ₁₀ , O ₁₂ ), and the respective sets are arranged horizontally on the same circumference in the upper and lower rows. In this case, 6 arranged at the vertex of the regular hexagon
The discharge electrodes are arranged with an angle difference of 30 ° up and down (called double staggered electrodes). In this case, the distance between the two planes is set to be substantially equal to the distance D between the electrodes. Due to such a three-dimensional electrode arrangement, a mutual discharge occurs between the upper six electrodes and the lower six electrodes, resulting in a multi-dimensional discharge.

As described in the above embodiment, by arranging the discharge electrodes in the order of their phases, the effect can be maximized. However, taking advantage of the feature of the present invention that a three-dimensional plasma region can be freely controlled, it is also possible to arrange them arbitrarily without depending on the order of phases according to the purpose.

"Discharge path shortened by arc plasma" As shown in FIG. 6, in the discharge by this apparatus, discharge from another electrode is performed toward the arc plasma region generated by the discharge. A lump of arc plasma as shown in FIG. 6 is generated in the discharge space. This causes the arc plasma region to act equivalently to a conductive metal.
As a result, since the discharge is performed in the generated arc plasma region, the discharge path is shortened.
This means that the discharge voltage decreases due to the shortening of the discharge path,
This leads to stabilization of discharge. The generation of such a three-dimensional arc plasma is an innovative invention that cannot be obtained with a conventional discharge device.

"First Embodiment of Six-Phase Multi-Dimensional Discharge" FIG. 4 and "Second Embodiment of Six-Phase Multi-Dimensional Discharge" As shown in FIG. When the electrode surfaces are divided into two, the planar discharge surfaces generated by these two sets of electrode surfaces are represented by S1 and S2, and the discharge formed three-dimensionally by a plurality of three-phase to twelve-phase AC conversion power supplies. The space is defined by the electrode surfaces S1 and S in FIG.
2, S3... Sn (n is a natural number). Here, the electrode surface S1 and the electrode surface S2 correspond to the first three phases.
A three-dimensional discharge (represented by # 1) obtained from a 12-phase AC conversion power supply and between the discharge surface S1 and the discharge surface S2.
Is as described above. Similarly, a three-dimensional discharge as shown in FIG.

It should be noted that a voltage having a phase difference of 30 degrees is generated between the electrode surface S1 and the electrode surface S2, and a similar phase difference is generated between the electrode surface S2 and the electrode surface S3. 30
That is, a high voltage is generated. All the secondary neutral points of the transformers of the plurality of three-phase to twelve-phase AC conversion power supplies used to obtain the electrode surfaces S1, S2, S3... Sn as shown in FIG. Due to the mutual connection, a three-dimensional discharge (represented by # 1 ′) between different power sources occurs between the electrode surface S2 and the electrode surface S3. Hereinafter, similarly, the next three-dimensional discharge (represented by # 2 ') will occur.

As described above, in the six-phase multi-dimensional discharge device, by multiplexing the three-phase discharge devices, the same three-phase
In addition to the three-dimensional discharge generated by the electrode surface by the 12-phase AC conversion power supply, the three-dimensional discharge generated by the electrode surface by the different three-phase to 12-phase AC conversion power supply is obtained.
In the multiplexed discharge space, it is possible to create a three-dimensional high-temperature region by a homogeneous and continuous arc plasma.

Further, by controlling the output current of the three-phase to twelve-phase AC conversion power source, the temperature at any position on the electrode surfaces S1 to Sn can be controlled.
The three-dimensional temperature distribution in the arc plasma region surrounded by Sn can be freely changed.

[0032]

As described above with reference to the embodiments,
In the 12-phase AC conversion power supply according to the present invention, the connection of the three-phase input on the primary side of the transformer is made by a star-star connection and a delta-star connection.
Using the phase difference of ゜, without using any semiconductor device for phase control at all, directly from three-phase AC with only a combination of transformers
Since two-phase alternating current can be generated, the device can be simplified,
Miniaturization and cost reduction are achieved, and industrial applications are extremely high.

In the six-phase multi-dimensional discharge device according to the present invention, a three-dimensional discharge occurs in a region surrounded by a plurality of electrodes, and a high-density and high-temperature plasma can be stably obtained. In the field of melt treatment of industrial wastes that require high temperatures, the treatment efficiency can be drastically increased, and the industrial application is very high.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a conversion from three-phase alternating current to 12-phase alternating current according to the present invention.

FIG. 2 is a vector diagram showing a relationship among three-phase, six-phase, and twelve-phase alternating currents.

FIG. 3 is a transformer connection diagram of the embodiment.

FIG. 4 is a schematic view of a first embodiment of a six-phase multiple discharge according to the present invention.

FIG. 5 is a schematic view of a second embodiment of the same six-phase multiple stereo discharge.

FIG. 6 is a conceptual diagram of a discharge path shortened by the arc plasma.

FIG. 7 is a configuration diagram of electrodes.

[Explanation of symbols]

R, S, T Commercial three-phase power input Vx, Vy, Vz Star connection primary side vector Vx ', Vy', Vz 'Star connection secondary side vector Vx ", Vy", Vz "Vx', Vy ', Vxδ, Vyδ, Vzδ Delta connection primary side vector Vxδ ′, Vyδ ′, Vzδ ′ Delta connection secondary side vector Vxδ, Vyδ, Vyδ ″, Vzδ ″ Vxδ ′, Vy
δ ', Vzδ' and 180 degree phase different vector T ₁ through T ₆ single-phase transformer N ₁ to N ₆ single-phase transformer secondary center tap (neutral point) _O 1 _{~ O 12} discharge electrodes S ₁ three-dimensional discharge surface caused by steric discharge surface # ₁ 'to _{# 2'} two different power caused by the discharge surface # ₁ to _{# 3} the same power supply caused by to S _n 6 pieces of electrodes

────────────────────────────────────────────────── (5) References JP-A-49-86243 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05H 1/36 H02M 5/14

Claims (3)

(57) [Claims] 1. A star connection of primary coils of single-phase transformers T ₁ , T ₂ , T ₃ having an intermediate tap on a secondary coil,
Similarly, delta-connected primary-side transformers T ₄ , T ₅ , and T ₆ having intermediate taps on secondary-side coils are respectively connected to a commercial three-phase AC power supply, and transformers T ₁ , T ₁ , The intermediate taps N ₁ , N ₂ , N ₃ , N ₄ , N ₅ , and N ₆ on the secondary side of T ₂ , T ₃ , T ₄ , T ₅ , and T ₆ are connected to each other, and this is used as a neutral point to form a single phase. Transformers T ₁ , T ₂ ,
The phase difference from the secondary output of T ₃ , T ₄ , T ₅ , T ₆ is 30
A different 12-phase alternating current can be taken out each time, and the degree of coupling between the primary side coil and the secondary side coil of the single-phase transformers T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T ₆ can be measured. A three-phase to twelve-phase AC conversion power supply characterized by being changed by a signal. 2. A single-phase transformer in which a primary coil is star-connected using the three-phase to twelve-phase AC conversion power supply according to claim 1.
6 discharges connected to the outputs from the vessels T ₁ , T ₂ , T ₃
Single phase transformer with delta connection of electrodes and primary coil
The six discharge currents connected to the outputs from T ₄ , T ₅ , T ₆
The poles are arranged as a group and are arranged horizontally on the circumference.
By multiplexing the plasma, a three-dimensional plasma is generated.
A six-phase multi-dimensional discharge device having a high-density discharge space in the center. 3. A three-dimensional temperature distribution of plasma is obtained by multiplexing a plurality of devices for generating a three-dimensional plasma obtained in claim 2 and controlling a current value flowing through an electrode group of each device. A six-phase multiplex three-dimensional discharge device which can be freely controlled.