JP2008123735A - Power source device for arc furnace - Google Patents

Power source device for arc furnace Download PDF

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JP2008123735A
JP2008123735A JP2006303630A JP2006303630A JP2008123735A JP 2008123735 A JP2008123735 A JP 2008123735A JP 2006303630 A JP2006303630 A JP 2006303630A JP 2006303630 A JP2006303630 A JP 2006303630A JP 2008123735 A JP2008123735 A JP 2008123735A
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arc furnace
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power supply
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JP5051345B2 (en
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Koji Hino
浩二 日野
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Fuji Electric Co Ltd
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Fuji Electric Systems Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a power source device for an arc furnace which can control an arc current almost at a same level irrespective of an impedance inside the arc furnace. <P>SOLUTION: The power source for an arc furnace to supply a direct current to the arc furnace by a power conversion unit includes a current adjusting means to work so that a deflection between a current set up value current and a current detected value of an arc current can become zero and a controlling means to control the arc current by driving a semiconductor element of the power conversion unit with an output of the current adjusting means as a control signal. The power source also includes a controlling signal correcting means 114 to correct a controlling signal by adding the arc voltage detected value to an output of the current adjusting unit 107A, when the arc detected value is suddenly changed and exceeds a predetermined value according to an impedance change inside the arc furnace by using a self-excitation conversion unit as a power conversion unit and using a current adjusting unit 107A of a short response time as the current adjusting means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、電力変換装置により直流アーク炉やプラズマアーク炉（以下、これらを総称して直流アーク炉というものとする）に直流電力を供給するアーク炉用電源装置に関し、詳しくは、溶融物の状態等に起因してアーク炉内のインピーダンスが変化した場合にもアーク電流をほぼ一定に制御可能としたアーク炉用電源装置に関するものである。   The present invention relates to a power supply device for an arc furnace that supplies DC power to a DC arc furnace or a plasma arc furnace (hereinafter collectively referred to as a DC arc furnace) by a power converter, and more particularly, The present invention relates to a power supply device for an arc furnace that makes it possible to control the arc current substantially constant even when the impedance in the arc furnace changes due to a state or the like.

図３は、従来の直流アーク炉用電源装置の基本的な構成図であり、例えば後述する特許文献１に記載されているものである。
以下、この従来技術の構成及び動作を略述する。 FIG. 3 is a basic configuration diagram of a conventional DC arc furnace power supply device, which is described, for example, in Patent Document 1 described later.
The configuration and operation of this prior art will be briefly described below.

まず、電源装置の主回路について説明すると、系統電圧は変圧器１０１により所定の大きさの交流電圧に降圧され、サイリスタからなる整流装置１０２により直流電圧に変換される。この直流電圧の正電位が直流リアクトル１０３を介してアーク炉炉体２０１の炉底電極に、負電位が直流リアクトル１０３を介してアーク炉電極２０２に印加されると、炉体２０１とアーク炉電極２０２との間にアーク電流が流れ、アーク炉電極２０２の先端からアークが発生して炉体２０１内のスクラップ等を溶融させるようになっている。
なお、後述するように２０３は電極昇降制御装置、２０４は電極昇降装置である。 First, the main circuit of the power supply apparatus will be described. The system voltage is stepped down to a predetermined AC voltage by the transformer 101 and converted to a DC voltage by the rectifier 102 formed of a thyristor. When a positive potential of the DC voltage is applied to the furnace bottom electrode of the arc furnace furnace 201 through the DC reactor 103 and a negative potential is applied to the arc furnace electrode 202 through the DC reactor 103, the furnace body 201 and the arc furnace electrode An arc current flows between the arc furnace electrode 202 and an arc is generated from the tip of the arc furnace electrode 202 to melt scrap and the like in the furnace body 201.
As will be described later, 203 is an electrode lifting control device, and 204 is an electrode lifting device.

次に、制御回路の構成及び動作を説明する。
整流装置１０２内のスイッチング素子の点孤位相角は、位相角制御装置１０３から出力されるゲート信号により制御され、整流装置１０２から出力されるアーク電流の値を制御する。電流検出器１０４により検出された変圧器１０１の二次側電流は電流変換器１０５にて所定の大きさの電流検出値に変換され、減算器１０６において、予め設定された電流設定値と電流検出値との偏差が求められる。 Next, the configuration and operation of the control circuit will be described.
The arc phase angle of the switching element in the rectifier 102 is controlled by a gate signal output from the phase angle controller 103, and controls the value of the arc current output from the rectifier 102. The secondary current of the transformer 101 detected by the current detector 104 is converted into a current detection value of a predetermined magnitude by the current converter 105, and a preset current set value and current detection are detected by the subtractor 106. Deviation from the value is determined.

更に、上記偏差がゼロとなるように、所定の時定数を持つ電流調節器（比例積分器または積分器）１０７が調節動作を行い、その出力が加算器１０８に入力される。
一方、電圧検出器１０９及び電圧変換器１１０を介して検出されたアーク電圧検出値（電圧フィードフォワード量）は前記加算器１０８により電流調節器１０７の出力と加算され、その加算信号が制御信号として位相角制御装置１０３に入力されている。 Further, a current regulator (proportional integrator or integrator) 107 having a predetermined time constant performs an adjustment operation so that the deviation becomes zero, and its output is input to the adder 108.
On the other hand, the arc voltage detection value (voltage feedforward amount) detected through the voltage detector 109 and the voltage converter 110 is added to the output of the current regulator 107 by the adder 108, and the added signal is used as a control signal. This is input to the phase angle control device 103.

位相角制御装置１０３は、上記制御信号に基づいて、電流設定値と電流検出値との偏差がゼロとなるような点弧位相角を求め、これをゲート信号として整流装置１０２に出力し、サイリスタの点弧角を制御する。
このように、従来の制御回路では、電流制御系の電流フィードバックループと電圧制御系の電圧フィードフォワードループとを組み合わせることにより、整流装置１０２から出力されるアーク電流の値を制御している。 Based on the control signal, the phase angle control device 103 obtains an ignition phase angle such that the deviation between the current set value and the current detection value becomes zero, and outputs this to the rectifier device 102 as a gate signal. Controls the firing angle of.
Thus, in the conventional control circuit, the value of the arc current output from the rectifier 102 is controlled by combining the current feedback loop of the current control system and the voltage feedforward loop of the voltage control system.

また、電圧変換器１１０の出力側に接続された電極昇降制御装置２０３は、内部の電圧設定値とアーク電圧検出値との偏差がゼロとなるように電極昇降装置２０４を昇降動作させることにより、アーク炉電極２０２の位置すなわちアークの長さで決まるアーク電圧を制御している。   In addition, the electrode lifting control device 203 connected to the output side of the voltage converter 110 moves the electrode lifting device 204 up and down so that the deviation between the internal voltage setting value and the arc voltage detection value becomes zero, The arc voltage determined by the position of the arc furnace electrode 202, that is, the arc length is controlled.

なお、図４は、図３における電流制御系及び電圧制御系のみを抜き出して示したものである。   FIG. 4 shows only the current control system and the voltage control system in FIG.

ここで、アーク電流Ｉｄとアーク電圧Ｖａｒｃとの間には、図５に示す不安定領域のように、アーク電流Ｉｄが減少するとアーク電圧Ｖａｒｃが急増する特性がある。この領域ではアークの発生状態が不安定であり、アークが消滅する可能性が高い。
一方、直流アーク炉では、スクラップ等の溶融物がその溶融過程で移動（倒壊）することによりアーク炉内のインピーダンスが変化し、これによってアーク電圧−電流特性の瞬間的な変動が発生し易い。このようなアーク電圧−電流特性の急変が図５における不安定領域で発生すると、アークが消滅する恐れがある。 Here, between the arc current I d and the arc voltage V arc, as in the unstable region shown in FIG. 5, there is a characteristic that an arc current I d decreases the arc voltage V arc surge. In this region, the arc generation state is unstable and the arc is highly likely to disappear.
On the other hand, in a DC arc furnace, a melted material such as scrap moves (collapses) during the melting process, so that the impedance in the arc furnace changes, and this easily causes an instantaneous change in arc voltage-current characteristics. If such a sudden change in arc voltage-current characteristics occurs in the unstable region in FIG. 5, the arc may disappear.

上述したアークの消滅を防止するために、図３の従来技術では、アーク電流の減少に反して増加するアーク電圧検出値を加算器１０８にて電流調節器１０７の出力に加算しており、これにより整流装置１０２の通流角を拡大してアークが消滅する前にできるだけ早くアーク電流を増加させるようにしている。   In order to prevent the disappearance of the arc described above, in the prior art of FIG. 3, an arc voltage detection value that increases against the decrease of the arc current is added to the output of the current regulator 107 by the adder 108. As a result, the flow angle of the rectifier 102 is increased to increase the arc current as soon as possible before the arc disappears.

特開平１０−２９４１７４号公報（段落［０００２］〜［００１０］、図６５等）JP-A-10-294174 (paragraphs [0002] to [0010], FIG. 65, etc.)

さて、図３に示した従来の直流アーク炉用電源装置では、整流装置１０２がサイリスタ等を用いた他励変換装置によって構成されている。
他励変換方式の場合、例えばサイリスタを三相ブリッジ結線して整流装置１０２を構成すると、サイリスタへの点弧信号のパルス幅は「商用周波数÷６＝数〔ｍｓ〕」となり、電流調節器１０７の応答を早くしても数〔ｍｓ〕以下の応答時間を得ることはできない。
このため、電流調節器１０７としては、応答時間（時定数）が数百〔ｍｓ〕程度のものを用いて平均値的制御を行わせ、アーク炉の瞬間的な電圧変動に対しては電流調節器１０７の後段で遅れの小さいアーク電圧検出値を加算することにより、アークの消滅を防いでいた。 Now, in the conventional DC arc furnace power supply shown in FIG. 3, the rectifier 102 is constituted by a separately excited conversion device using a thyristor or the like.
In the case of the separately excited conversion method, for example, when the rectifier 102 is configured by connecting thyristors in a three-phase bridge, the pulse width of the ignition signal to the thyristors is “commercial frequency ÷ 6 = several [ms]”. Even if the response is made earlier, a response time of several [ms] or less cannot be obtained.
For this reason, the current regulator 107 has a response time (time constant) of about several hundreds [ms] to perform average control, and the current regulator 107 for the instantaneous voltage fluctuation of the arc furnace. The arc disappearance was prevented by adding the arc voltage detection value with a small delay at the subsequent stage of the unit 107.

しかし、アークの変化速度は一定でなく、アーク炉内の溶融物の状態に応じたインピーダンスの変化によって左右される。
例えば、図６は、アーク電圧Ｖａｒｃ、電流調節器出力及びアーク電流Ｉｄの時間変化を示す図である。同図の時刻ｔ０以後、溶融物の状態に応じてアーク炉のインピーダンスが電流調節器１０７の時定数と同程度で増加していくと、アーク電流Ｉｄは徐々に減少し、アーク電圧Ｖａｒｃは徐々に増加していく。 However, the rate of change of the arc is not constant and depends on the change in impedance according to the state of the melt in the arc furnace.
For example, FIG. 6 is a diagram illustrating temporal changes in the arc voltage V arc , the current regulator output, and the arc current I d . After the time t 0 in the figure, when the arc furnace impedance increases in the same degree as the time constant of the current regulator 107 according to the state of the melt, the arc current Id gradually decreases and the arc voltage V arc gradually increases.

この間、アーク電流Ｉｄの減少によるアークの消滅を防止するように、前述した如く電流調節器１０７の出力は徐々に増加する。しかし、インピーダンスの増加に伴ってアーク電流Ｉｄがその後も減少し続けると、時刻ｔ１において電流調節器１０７の出力は飽和するに至る。
その後、時刻ｔ２において、溶融物の状態が変化してインピーダンスが急激に減少したとすると、この時点では電流調節器１０７の出力が飽和状態にあり、また、電流調節器１０７は時定数が大きいため、インピーダンスの急激な減少に追従することができず、アーク電流Ｉｄがオーバーシュートすることとなる。 During this time, to prevent extinction of the arc by reducing arc current I d, the output of the current regulator 107 as described above is gradually increased. However, if the arc current I d continues to decrease as the impedance increases, the output of the current regulator 107 saturates at time t 1 .
Then, at time t 2, the the impedance changes the state of the melt and rapidly reduced at this point is the output saturation current regulator 107, The current adjuster 107 is large time constant Therefore, it is impossible to follow the rapid decrease in impedance, and the arc current Id is overshooted.

このような動作は、アーク炉内のインピーダンス変化に関わらずアーク電流Ｉｄを一定に保つ制御と相反するものであり、インピーダンスの値によっては過電流による装置停止など、設備や操業への悪影響を招くおそれがあった。 Such an operation is contrary to the control that keeps the arc current I d constant regardless of the impedance change in the arc furnace, and depending on the impedance value, there is an adverse effect on facilities and operations such as equipment shutdown due to overcurrent. There was a risk of inviting.

そこで、本発明の解決課題は、アーク炉内のインピーダンス変化に関わらずアーク電流をほぼ一定に制御可能とした直流アーク炉用電源装置を提供することにある。   Therefore, a problem to be solved by the present invention is to provide a DC arc furnace power supply apparatus that can control the arc current substantially constant regardless of the impedance change in the arc furnace.

上記課題を解決するため、請求項１に記載した発明は、電力変換装置によりアーク炉に直流電力を供給するアーク炉用電源装置であって、
アーク電流の電流設定値と電流検出値との偏差をゼロにするように動作する電流調節手段と、この電流調節手段の出力を制御信号として前記電力変換装置の半導体素子を駆動することによりアーク電流を制御する手段と、を備えたアーク炉用電源装置において、
前記電力変換装置として自励変換装置を用い、かつ、前記電流調節手段として応答時間が短い電流調節手段を用いると共に、
アーク炉内のインピーダンス変化に伴いアーク電圧検出値が急変して設定値を超えた時に、前記アーク電圧検出値を前記電流調節手段の出力に加算して前記制御信号を補正する制御信号補正手段を備えたものである。 In order to solve the above-mentioned problem, the invention described in claim 1 is a power supply device for an arc furnace that supplies DC power to the arc furnace by a power converter,
Current adjusting means that operates so that the deviation between the current set value of the arc current and the detected current value becomes zero, and the arc current by driving the semiconductor element of the power converter using the output of the current adjusting means as a control signal And an arc furnace power supply device comprising:
While using a self-excited conversion device as the power conversion device, and using a current adjustment means with a short response time as the current adjustment means,
Control signal correction means for correcting the control signal by adding the arc voltage detection value to the output of the current adjusting means when the arc voltage detection value suddenly changes with the impedance change in the arc furnace and exceeds a set value. It is provided.

請求項２に記載した発明は、請求項１に記載したアーク炉用電源装置において、前記アーク電圧検出値が増加して前記設定値を超えた時に、前記制御信号補正手段により補正された前記制御信号によってアーク電流を増加させるものである。   According to a second aspect of the present invention, in the arc furnace power supply device according to the first aspect, the control corrected by the control signal correcting means when the detected value of the arc voltage increases and exceeds the set value. The arc current is increased by the signal.

請求項３に記載した発明は、請求項１または２に記載したアーク炉用電源装置において、
前記制御信号補正手段を、
アーク電圧検出値が入力されるハイパスフィルタ手段と、このハイパスフィルタ手段の出力が前記設定値を超えた時に信号を出力する比較手段と、この比較手段から出力される前記信号によりオンしてアーク電圧検出値を前記電流調節手段の出力に加算するスイッチ手段と、により構成したものである。 The invention described in claim 3 is the power supply device for an arc furnace according to claim 1 or 2,
The control signal correcting means;
A high-pass filter means to which an arc voltage detection value is input, a comparison means for outputting a signal when the output of the high-pass filter means exceeds the set value, and an arc voltage that is turned on by the signal output from the comparison means And switch means for adding the detected value to the output of the current adjusting means.

本発明によれば、アーク電圧の変化が急激でない場合には、応答時間が短い電流調節器の出力のみから生成した制御信号を用いて自励変換装置に対する電流制御を行い、アーク電圧の変化が急激であって所定の設定値を超えた場合には、アーク電圧検出値を電流調節器の出力に加算して得た制御信号を用いて自励変換装置を制御することにより、アーク炉内の溶融物の状態に関わらずアーク電流をほぼ一定に制御することができる。また、アーク電流のオーバーシュートを抑制して過電流による運転停止など、設備や操業に悪影響が及ぶのを未然に防止することができる。   According to the present invention, when the change in the arc voltage is not abrupt, current control is performed on the self-excited conversion device using the control signal generated only from the output of the current regulator with a short response time. When it is abrupt and exceeds a predetermined set value, by controlling the self-excited conversion device using a control signal obtained by adding the arc voltage detection value to the output of the current regulator, The arc current can be controlled to be substantially constant regardless of the state of the melt. Moreover, it is possible to prevent the facility and operation from being adversely affected, such as operation stop due to overcurrent by suppressing the overshoot of the arc current.

以下、図に沿って本発明の実施形態を説明する。
まず、本実施形態では、アーク炉に直流電力を供給する電力変換装置として、自励変換装置を用いている。この自励変換装置としては、例えばＩＧＢＴやパワーＭＯＳＦＥＴ、パワートランジスタのように自己消弧機能を持つ半導体素子によりデバイス転流を行わせる直流チョッパ等が考えられるが、他の構成または転流方式の自励変換装置であっても良い。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, in the present embodiment, a self-excited conversion device is used as a power conversion device that supplies DC power to an arc furnace. As this self-excited conversion device, for example, a direct current chopper that performs device commutation by a semiconductor element having a self-extinguishing function such as an IGBT, a power MOSFET, or a power transistor can be considered. A self-excited conversion device may be used.

上記自励変換装置の制御回路を構成する電流制御系及び電圧制御系は、図１のように構成されている。なお、図１では、図４と同一の構成要素には同一の番号を付してあり、以下では異なる部分を中心に説明する。
図１において、１０７Ａは電流設定値と電流検出値との偏差が入力される電流調節器であり、応答時間（時定数）が比較的短いものである。便宜的に、この電流調節器１０７Ａを瞬時ＡＣＲともいう。 A current control system and a voltage control system constituting the control circuit of the self-excited conversion device are configured as shown in FIG. In FIG. 1, the same components as those in FIG. 4 are denoted by the same reference numerals, and different parts will be mainly described below.
In FIG. 1, reference numeral 107A denotes a current regulator to which a deviation between a current setting value and a current detection value is input, and has a relatively short response time (time constant). For convenience, the current regulator 107A is also referred to as an instantaneous ACR.

電流調節器１０７Ａはその入力偏差をゼロとするように調節動作するものであり、従来と同様に電流制御系を構成している。
また、電流調節器１０７Ａの出力は加算器１０８に入力されていると共に、この加算器１０８には、スイッチ１１１を介してアーク電圧検出値も入力されている。更に、アーク電圧検出値は、ハイパスフィルタ１１２を介して比較器１１３に入力されており、比較器１１３では、ハイパスフィルタ１１２を経たアーク電圧検出値が設定値を超えた場合にオン信号を出力し、このオン信号によって前記スイッチ１１１をオンするように構成されている。
ここで、加算器１０８、スイッチ１１１、ハイパスフィルタ１１２及び比較器１１３は、
制御信号補正手段１１４を構成している。 The current regulator 107A performs an adjustment operation so that the input deviation is zero, and constitutes a current control system as in the conventional case.
The output of the current regulator 107A is input to the adder 108, and the arc voltage detection value is also input to the adder 108 via the switch 111. Further, the detected arc voltage value is input to the comparator 113 via the high pass filter 112, and the comparator 113 outputs an ON signal when the detected arc voltage value that has passed through the high pass filter 112 exceeds the set value. The switch 111 is turned on by the ON signal.
Here, the adder 108, the switch 111, the high-pass filter 112, and the comparator 113 are
The control signal correction unit 114 is configured.

次に、この実施形態の動作を説明する。
図２は、本実施形態におけるアーク電圧Ｖａｒｃ、電流調節器出力及びアーク電流Ｉｄの時間変化を実線によって示した図であり、従来技術におけるアーク電圧Ｖａｒｃ及びアーク電流Ｉｄも一点鎖線にて示してある。 Next, the operation of this embodiment will be described.
FIG. 2 is a diagram showing the change over time of the arc voltage V arc , the current regulator output, and the arc current I d in the present embodiment by a solid line, and the arc voltage V arc and the arc current I d in the prior art are also shown by a one-dot chain line. It is shown.

図２の時刻ｔ１０において、アーク炉内の溶融物の状態に応じてアーク炉のインピーダンスが変化したとしても、その変化が急激なものでない限り、時定数の短い電流調節器１０７Ａがアーク電流Ｉｄの変化に追従して瞬時に動作することにより、時刻ｔ１０以後、アーク電流Ｉｄ及びアーク電圧Ｖａｒｃはほぼ一定に保たれる。 At time t 10 of FIG. 2, as impedance state arc furnace according to the melt of the arc furnace is changed, as long as the change is not one sudden, when the arc short current regulator 107A of constant current I By instantaneously following the change in d , the arc current I d and the arc voltage V arc are kept substantially constant after time t 10 .

その後、時刻ｔ１１において、溶融物の状態が変化してインピーダンスが急激に増加すると、アーク電圧Ｖａｒｃも急激に増加する。このアーク電圧Ｖａｒｃの急変は図１のハイパスフィルタ１１２により抽出され、後段の比較器１１３において設定値を超えた時点で比較器１１３からオン信号が出力される。これにより、スイッチ１１１がオンして加算器１０８にはアーク電圧検出値が入力されるため、電流調節器１０７Ａの出力とアーク電圧検出値との加算値が制御信号として出力される。 Then, at time t 11, the impedance changes the state of the melt increases rapidly, also increases sharply arc voltage V arc. The sudden change in the arc voltage V arc is extracted by the high-pass filter 112 shown in FIG. 1, and an ON signal is output from the comparator 113 when the comparator 113 in the subsequent stage exceeds the set value. As a result, the switch 111 is turned on, and the detected arc voltage value is input to the adder 108, so that the added value of the output of the current regulator 107A and the detected arc voltage value is output as a control signal.

上記制御信号は、自励変換装置の半導体素子を駆動するための駆動信号（ゲート信号やベース信号）の生成に用いられるが、直流アーク炉用の電力変換装置として、サイリスタ整流装置のように点弧信号のパルス幅が制約される他励変換装置ではなく、チョッパ等の自励変換装置を用いることにより、上記制御信号に従って自励変換装置による高速応答の電流制御を行うことができる。   The control signal is used to generate a drive signal (gate signal or base signal) for driving a semiconductor element of the self-excited conversion device. By using a self-excited conversion device such as a chopper instead of a separately-excited conversion device in which the pulse width of the arc signal is restricted, high-speed response current control can be performed by the self-excited conversion device according to the control signal.

図２において、時刻ｔ１１以後はアーク電流Ｉｄが減少すると共にアーク電圧Ｖａｒｃが急激に増加するが、アーク電圧Ｖａｒｃが時刻ｔ１２において比較器１１３の設定値を超えれば、それ以後は、アーク電圧検出値を電流調節器１０７Ａの出力に加算して得た制御信号を用いて自励変換装置の半導体素子をスイッチングすることでアーク電流Ｉｄを増加させることができ、時刻ｔ１２以後はアーク電圧Ｖａｒｃが低下していくことになる。
この間、図示するように電流調節器１０７Ａの出力は一時的に飽和するが、アーク電圧Ｖａｒｃの急激な低下に伴ってアーク炉内のインピーダンスが復帰した後、電流調節器１０７Ａの小さな時定数によって時刻ｔ１３で飽和が解けるため、アーク電流Ｉｄのオーバーシュートも小さくなる。 In FIG. 2, the arc current I d decreases and the arc voltage V arc increases rapidly after time t 11. However, if the arc voltage V arc exceeds the set value of the comparator 113 at time t 12 , thereafter , it is possible to increase the arc current I d by switching the semiconductor device of the self-excited converter using a control signal obtained by adding the arc voltage detection value at the output of the current regulator 107A, the time t 12 after Will cause the arc voltage V arc to decrease.
During this time, as shown in the figure, the output of the current regulator 107A saturates temporarily, but after the impedance in the arc furnace is restored as the arc voltage V arc decreases rapidly, the current regulator 107A has a small time constant. since at time t 13 saturated melts, overshoot of the arc current I d is also small.

以上のように、本実施形態によれば、アーク電圧が変化したとしてもその変化が急激でない場合には、応答が早い電流調節器１０７Ａの出力のみを制御信号に用いて電流制御を行い、アーク電圧の変化が急激な場合（例えばアーク電圧が急増した場合）にはハイパスフィルタ１１２、比較器１１３及びスイッチ１１１の動作によりアーク電圧検出値を電流調節器１０７Ａの出力に加算して得た制御信号を用いてアーク電流を増加させるような制御が行われるため、アーク炉内の溶融物の状態、言い換えればアーク炉内のインピーダンスに依存することなくアーク電流Ｉｄをほぼ一定に制御することができる。また、アーク電流Ｉｄのオーバーシュートを抑制できるので、過電流による運転停止など、設備や操業への悪影響を招く恐れもない。 As described above, according to the present embodiment, even if the arc voltage changes, if the change is not abrupt, current control is performed using only the output of the current regulator 107A having a quick response as a control signal, When the voltage change is abrupt (for example, when the arc voltage suddenly increases), the control signal obtained by adding the arc voltage detection value to the output of the current regulator 107A by the operation of the high pass filter 112, the comparator 113 and the switch 111. since the control for increasing the arc current with a place, it can be controlled substantially constant without arc current I d to dependency of the melt arc furnace, the impedance of the arc furnace in other words . Further, since the overshoot of the arc current I d can be suppressed, and shutdown due to an overcurrent, there is no risk of causing adverse effects on the facility and operation.

なお、チョッパを用いたゴミ焼却灰溶融炉用電源装置が特開２００１−２０１０２１号公報に記載されている。この従来技術に係る電源装置は、チョッパを構成するスイッチング素子のスイッチング期間を制御してアークを安定させるものであるが、本発明のごとく、アーク電圧急変時にアーク電圧検出値によるフィードフォワード制御を電流フィードバック制御と組み合わせる構成は何ら開示されていない。
また、チョッパを用いたアーク炉用電源装置が特開２００３−２１９６４９号公報に記載されている。しかし、この従来技術に係る電源装置の解決課題は、入力電圧の瞬時停止が発生した場合でもアーク電流をある程度持続させることにあって本発明の解決課題と相違しており、上述したフィードフォワード制御手段も何ら開示されていないものである。 In addition, the power supply apparatus for refuse incineration ash melting furnaces using a chopper is described in Unexamined-Japanese-Patent No. 2001-201021. This power supply device according to the prior art controls the switching period of the switching elements constituting the chopper to stabilize the arc. However, as in the present invention, the feedforward control based on the arc voltage detection value is performed when the arc voltage suddenly changes. No configuration is disclosed in combination with feedback control.
A power supply device for an arc furnace using a chopper is described in Japanese Patent Application Laid-Open No. 2003-219649. However, the problem of the power supply device according to this prior art is that the arc current is maintained to some extent even when an instantaneous stop of the input voltage occurs, which is different from the problem of the present invention. No means are disclosed.

本発明の実施形態の主要部を示す構成図である。It is a block diagram which shows the principal part of embodiment of this invention. 本発明の実施形態による、アーク電圧、電流調節器出力及びアーク電流の時間変化を示す図である。It is a figure which shows the time change of an arc voltage, a current regulator output, and an arc current by embodiment of this invention. 従来の直流アーク炉用電源装置の基本的な構成図である。It is a basic block diagram of the conventional DC arc furnace power supply device. 図３の主要部を示す構成図である。It is a block diagram which shows the principal part of FIG. アーク電流とアーク電圧との関係を示す図である。It is a figure which shows the relationship between an arc current and an arc voltage. アーク電圧、電流調節器出力及びアーク電流の時間変化を示す図である。It is a figure which shows the time change of an arc voltage, a current regulator output, and an arc current.

符号の説明Explanation of symbols

１０６，１０８：加算器
１０７Ａ：電流調節器
１１１：スイッチ
１１２：ハイパスフィルタ
１１３：比較器
１１４：制御信号補正手段 106, 108: Adder 107A: Current regulator 111: Switch 112: High-pass filter 113: Comparator 114: Control signal correction means

Claims (3)

電力変換装置によりアーク炉に直流電力を供給するアーク炉用電源装置であって、
アーク電流の電流設定値と電流検出値との偏差をゼロにするように動作する電流調節手段と、この電流調節手段の出力を制御信号として前記電力変換装置の半導体素子を駆動することによりアーク電流を制御する手段と、を備えたアーク炉用電源装置において、
前記電力変換装置として自励変換装置を用い、かつ、前記電流調節手段として応答時間が短い電流調節手段を用いると共に、
アーク炉内のインピーダンス変化に伴いアーク電圧検出値が急変して設定値を超えた時に、前記アーク電圧検出値を前記電流調節手段の出力に加算して前記制御信号を補正する制御信号補正手段を備えたことを特徴とするアーク炉用電源装置。 A power supply device for an arc furnace that supplies direct-current power to the arc furnace by a power converter,
Current adjusting means that operates so that the deviation between the current set value of the arc current and the detected current value becomes zero, and the arc current by driving the semiconductor element of the power converter using the output of the current adjusting means as a control signal And an arc furnace power supply device comprising:
While using a self-excited conversion device as the power conversion device, and using a current adjustment means with a short response time as the current adjustment means,
Control signal correction means for correcting the control signal by adding the arc voltage detection value to the output of the current adjusting means when the arc voltage detection value suddenly changes with the impedance change in the arc furnace and exceeds a set value. A power supply device for an arc furnace, comprising: 請求項１に記載したアーク炉用電源装置において、
前記アーク電圧検出値が増加して前記設定値を超えた時に、前記制御信号補正手段により補正された前記制御信号によってアーク電流を増加させることを特徴とするアーク炉用電源装置。 In the arc furnace power supply device according to claim 1,
An arc furnace power supply device, wherein when the detected arc voltage value increases and exceeds the set value, the arc current is increased by the control signal corrected by the control signal correcting means. 請求項１または２に記載したアーク炉用電源装置において、
前記制御信号補正手段を、
アーク電圧検出値が入力されるハイパスフィルタ手段と、このハイパスフィルタ手段の出力が前記設定値を超えた時に信号を出力する比較手段と、この比較手段から出力される前記信号によりオンしてアーク電圧検出値を前記電流調節手段の出力に加算するスイッチ手段と、により構成したことを特徴とするアーク炉用電源装置。 In the arc furnace power supply device according to claim 1 or 2,
The control signal correcting means;
A high-pass filter means to which an arc voltage detection value is input, a comparison means for outputting a signal when the output of the high-pass filter means exceeds the set value, and an arc voltage that is turned on by the signal output from the comparison means An arc furnace power supply comprising: switch means for adding the detected value to the output of the current adjusting means.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010236723A (en) * 2009-03-30 2010-10-21 Kitashiba Electric Co Ltd Alarm device of induction melting furnace
CN110888001A (en) * 2018-09-11 2020-03-17 株洲中车时代电气股份有限公司 Direct-current network voltage mutation test device and implementation method of direct-current network voltage mutation test

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JPH0794275A (en) * 1993-09-27 1995-04-07 Mitsubishi Electric Corp Power supply device for dc arc furnace
JPH10294174A (en) * 1997-04-21 1998-11-04 Mitsubishi Electric Corp Power control device
JP2001201021A (en) * 2000-01-14 2001-07-27 Sansha Electric Mfg Co Ltd Power unit for garbage incinerated ash fusing furnace

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0794275A (en) * 1993-09-27 1995-04-07 Mitsubishi Electric Corp Power supply device for dc arc furnace
JPH10294174A (en) * 1997-04-21 1998-11-04 Mitsubishi Electric Corp Power control device
JP2001201021A (en) * 2000-01-14 2001-07-27 Sansha Electric Mfg Co Ltd Power unit for garbage incinerated ash fusing furnace

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010236723A (en) * 2009-03-30 2010-10-21 Kitashiba Electric Co Ltd Alarm device of induction melting furnace
CN110888001A (en) * 2018-09-11 2020-03-17 株洲中车时代电气股份有限公司 Direct-current network voltage mutation test device and implementation method of direct-current network voltage mutation test
CN110888001B (en) * 2018-09-11 2021-08-13 株洲中车时代电气股份有限公司 Direct-current network voltage mutation test device and implementation method of direct-current network voltage mutation test

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