JP3693796B2

JP3693796B2 - Electric motor drive for paper machine

Info

Publication number: JP3693796B2
Application number: JP27834197A
Authority: JP
Inventors: 理博鈴木
Original assignee: Toshiba Mitsubishi Electric Industrial Systems Corp
Current assignee: Toshiba Mitsubishi Electric Industrial Systems Corp
Priority date: 1997-10-13
Filing date: 1997-10-13
Publication date: 2005-09-07
Anticipated expiration: 2017-10-13
Also published as: JPH11122964A

Description

【０００１】
【発明の属する技術分野】
本発明は、過負荷保護停止することなく当該装置または電動機の最大能力で連続運転の可能な抄紙機用電動機駆動装置に関する。
【０００２】
【従来の技術】
図１１は本発明の適用対象の一例である従来の電動機駆動装置の主要部の構成を示したものである。同図において、１は速度設定値信号ａの変化率を変化率制限値信号ｂにより制限し速度基準信号ｃを出力する変化率制限回路、２は速度制御回路、３は第１の電流指令信号ｉを出力する電流制御回路、４は入力された電流指令信号ｉを電流制限値信号ｒにより制限し第２の電流指令信号ｈを出力する電流制限回路、５は電力変換回路、７は紙を連続して抄造する抄紙機の搬送ロールに減速機を介してまたは直接接続した電動機、６は電力変換回路５と電動機７との間の電流ｌを検出し電流帰還信号ｍを出力する電流検出器、８は電動機の速度を検出し速度帰還信号ｊを出力する速度検出器、９は負荷率を演算し負荷率演算値信号ｎを出力する負荷率演算回路、１０は負荷率演算値信号ｎと保護判定値信号ｏの大小比較を行い保護指令信号ｐを出力する保護判定回路である。なおこの電動機駆動装置においては、変化率制限値信号ｂ及び電流制限値信号ｒの制限値は固定値に設定されている。
【０００３】
この電動機駆動装置は、電動機７が過熱により破壊されるのを防止するため、電流検出器６で検出した電流値ｌより負荷率演算回路９で負荷率ｎを演算し、その値ｎが保護限界判定値ｏに到達したら保護判定回路１０は電動機７への電力供給または電動機７からの回生電力を遮断する保護指令信号ｐを電力変換回路５に対して出力し、電動機７への電力供給と回生電流を遮断し惰性で回転させることで電動機７を保護している。
【０００４】
なお電流制御と呼ばれる部分は電動機７にとって比例関係であるトルク制御と呼ばれる場合もある。またこの電動機駆動装置は、直流電動機駆動装置、交流電動機駆動装置の別は問わない。
【０００５】
ここで、負荷率ｎの演算にはいろいろな演算方式があるが、一例として図１２に、単位時間当たりの電流実効値を利用した方式を示す。電流検出器６で検出された微少時間毎の電流値ｌを乗算器９１で二乗し、絶対値として移動平均出力回路９２で単位時間分累積し移動平均をとりスタック９３に蓄積する。これを加算回路９４で対象保護時間分加算し、対象時間（例えば５分間）当たりの負荷率値ｎとする。電動機７の定格値より定格範囲内の警告値と限界値を予め計算しておき判定定数として格納しておく。保護判定回路１０で、演算結果ｎと判定定数ｏとを比較し、演算結果が警告値以上になった時点で過負荷警報信号出力、過負荷のままだと演算値が限界値以上になった時点で電力変換回路５の電力変換器遮断、出力電力線遮断とし、電動機７を惰性で停止させる。
【０００６】
【発明が解決しようとする課題】
抄造ラインにおいて、増産を目的とした増速改造を行う場合がある。この時、設備投資能力によって電動機駆動装置の容量増加および容量の大きな電動機への更新ができないことがある。このように電動機駆動装置または電動機の容量不足気味の操業中において、各運動部分のグリス劣化、蒸気過多によるドライヤ内部のドレイン溜り、短時間問隔での加速操作と減速操作の繰り返しなどの種々の過負荷要因によって電動機が過負荷保護停止になりやすい。一旦過負荷保護停止になった場合、再始動のためには電動機駆動装置内部の検査、機械周りの点検作業および過負荷原因の特定と対策が必要であり、特に電動機速度がある程度高速状態に惰性停止となると慣性モーメントの大きなロールにおいては停止まで長時間かかる。停止までの待ち時間および検査・原因調査・対策にかかる抄造ラインの停止時間による減産が問題になる。
【０００７】
本発明は、以上の点に鑑みて為されたもので、過負荷保護停止することなく安定に運転を継続でき、操業上の過負荷保護停止発生によるロス時間を削減できる抄紙機用電動機駆動装置を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明に係る抄紙機用電動機駆動装置は、紙を連続して抄造する抄紙機の搬送ロールに減速機を介してまたは直接接続した電動機と、この電動機を駆動する手段と、この電動機の負荷率演算値を求める演算手段と、この手段により得られた負荷率演算値が保護停止となる負荷率より低い所定の値となったとき電流指令値を制限する所定の電流制限値信号を発生する電流制限値信号発生手段とを具備し、電動機が過負荷運転時においても保護停止せず連続運転が可能となるようにしたことを特徴とする。
【０００９】
このような構成とすることにより、電動機を過負荷保護停止することなく連続運転できるため、過負荷保護停止発生によるロス時間を削減できる。
ここで、電流制限値信号発生手段は、電流制限値信号を発生するとき、電流制限開始負荷率と電流制限開放負荷率にヒステリシス特性を有する電流制限値信号を発生するものであってもよい。
【００１０】
このような構成のものは、再加速、または加速後の減速に際し、その操作時点で負荷率演算値に余裕を持たせられるため、加減速操作の頻度が大きい場合に有効である。
【００１１】
さらに、電流制限値信号発生手段は、過去の負荷率計算値と現在の負荷率から将来の負荷率を予測する手段を含み、この手段で得られた負荷率演算値が保護停止となる負荷率より低い所定の値となったとき電流指令値を制限する所定の電流制限値信号を発生するものであってもよい。
【００１２】
このような構成のものは、負荷率演算の応答が遅く、その影響で電流制限をかけてもなお負荷率演算値が増加してしまう場合に有効である。
また、本発明は、負荷率演算値が保護停止となる負荷率より低い所定の値となったとき電流指令値を制限する所定の電流制限値信号を発生する制限値信号発生手段の代わりに、負荷率演算値が保護停止となる負荷率より低い所定の値となったとき速度基準指令の変化率を制限する所定の変化率制限値信号を発生する変化率制限値信号発生手段を具備することとしてもよい。
【００１３】
このような構成とすることによっても、電動機を過負荷保護停止することなく連続運転できるため、過負荷保護停止発生によるロス時間を削減できる。
また、電流制限値信号発生手段または変化率制限値信号発生手段は、現在負荷率と、設定された停止時間または設定された速度に至るまでの時間に必要となる負荷率とを加えた負荷率が、保護停止となる負荷率より低い所定の値となったとき、電流指令値を制限する所定の電流制限値信号または速度基準指令の変化率を制限する所定の変化率制限値信号を発生するものであってもよい。
【００１４】
このような構成のものは、過負荷保護停止することなしに所望の減速時間内で確実に減速させたい場合に有効である。
更に本発明は、このような抄紙機用電動機駆動装置を複数台使用して抄紙機ラインを構成した抄紙機用電動機駆動装置において、個々の電動機駆動装置より得られた変化率制限値信号の制限値の内、制限値が最小値である変化率制限値信号を選択する手段と、選択された最小値の速度基準変化率制限値信号により抄紙機ラインの速度基準の変化率を制限する手段とを具備したことを特徴とする。
【００１５】
このような構成とすることにより、完全通紙の連続操業状態においても、過負荷が最も大きい電動機駆動装置より得られる速度変化率制限値によってライン全体の速度変化率を制限するので、ライン全体を加速した場合でも全電動機の速度変化率を一定にでき安定な操業ができる。
【００１６】
【発明の実施の形態】
以下、図面を参照して、本発明の実施形態について詳細に説明する。なお、以下の図面において、従来例を示す図１１及び図１２を含めて同符号は同一部分又は対応部分を示す。
【００１７】
（第１の実施形態）
この実施形態は、負荷率演算値を監視しその時々の負荷率に応じて過負荷保護停止にならないように電流制限することで過負荷保護停止することなしに安定に運転を継続できるよう電動機駆動装置を構成したものである。
【００１８】
図１に本発明の第１の実施形態に係る電動機駆動装置の主要部の構成を示す。同図において、符号１から符号１０で示す部分は従来の電動機駆動装置として説明した図１１のものと同じ構成である。また、１２は負荷率演算値ｎと過負荷保護値範囲内のある値（即ち保護停止となる負荷率より低いある値）ｑとの大小比較を行い、電流制限値ｒを演算する負荷率判定回路である。
【００１９】
負荷率判定回路１２の動作特性を図２に示す。
負荷率演算値ｎが負荷率判定値ｑより小さい範囲では１００％以上（例えば１５０％）の電流制限値信号ｒを出力し、ｑ以上で１００％以下（例えば８０％）の電流制限値信号ｒを出力する。この電流制限値信号ｒは電流制限回路４に供給される。
【００２０】
このようにして、電流制限回路４は、負荷率演算値ｎが過負荷保護値範囲内のある値ｑを超えたら、電動機７に流れる電流を小さくするよう電流指令制限を強め負荷率演算値ｎを減少させるように電動機７を運転する。負荷率演算値ｎに余裕ができたら電流制限を弱めて電動機７を運転する。
【００２１】
本実施形態が適用できる負荷状況としては、電動機容量としては１００％以下でも加速可能ではあるが、希望加速度が大きく計画されている抄紙機用電動機の場合に育効である。
【００２２】
このように構成した電動機駆動装置によれば過負荷保護停止することなく連続運転できるため、過負荷保護停止発生によるロス時間を削減できる抄紙機用電動機駆動装置を構成できる。
【００２３】
（第２の実施形態）
次に、本発明の第２の実施形態に係る電動機駆動装置について説明する。
第２の実施形態の構成は、図１に示すものと同じでよいが、図１の負荷率判定回路１２に判定条件を増やした構成となる。
【００２４】
図３に負荷率判定回路１２の動作特性を示す。
負荷率判定回路１２は運転初期時に１００％以上の電流制限値信号ｒを出力しているが、負荷率演算値ｎが第２の負荷率判定値（即ち電流制限開始負荷率判定値）ｑ２より大きい範囲で１００％以下の電流制限値信号ｒを出力し、負荷率演算値ｎがｑ２より小さい第１の負荷率判定値（即ち電流制限開放負荷率判定値）ｑ１まで減少したら１００％以上の電流制限値信号ｒを出力するように、判定にヒステリシス特性を持たせるように構成する。
【００２５】
本実施形態が適用できる負荷状況としては、電動機容量としては１００％以下でも加速可能ではあるが、希望加速度が大きく計画されている場合で且つ加減速操作の頻度が大きい場合に有効である。すなわち、再加速、または加速後の減速に際し、その操作時点で負荷率演算値に余裕を持たせられるようにしている。
【００２６】
（第３の実施形態）
次に、本発明の第３の実施形態に係る電動機駆動装置について説明する。
本実施形態は、過去の負荷率と現在の負荷率から将来の負荷率を予測し、この負荷率演算値を監視するように構成したものである。
【００２７】
図４に第３の実施形態の主要部の構成を示す。
本実施形態は、図１の負荷率判定回路１２の入力側に負荷率ｎの変化率ｚを演算する負荷率変化検出回路１３と変化率ｚに対し負荷率演算回路９の応答遅れからくるオーバーシュート分を予測するため、オーバーシュート予測負荷率ｋを演算する関数発生器１４および負荷率演算回路９の出力した負荷率演算値ｎにオーバーシュート予測負荷率ｋを加算する加算器１５を追加し、加算器１５の出力ｕを負荷率判定回路１２に入力する構成とする。
【００２８】
本実施形態は負荷率演算回路９の負荷率演算の応答が遅く、その影響で電流制限を掛けてもなお負荷率演算値が増加してしまう場合に有効である。負荷の特性により負荷率判定回路１２は、図３のようにヒステリシス特性を持っているもの、図２のように持たないものどちらかを選定すれば良い。
【００２９】
（第４の実施形態）
次に、本発明の第４の実施形態に係る電動機駆動装置について説明する。
図５に第４の実施形態の主要部の構成を示す。
本実施形態は、図１の負荷率判定回路１２に入力する負荷率値を通常の負荷率演算回路９の出力ｎに停止予測負荷率演算値ｓを加算器１６で加えた値ｕとする。停止予測負荷率演算値ｓは、現在速度ｊと任意に与えられる停止時間（または任意の速度に至るまでの時間）ｖとから、停止まで（または任意の速度に至るまで）に必要とする回生電流成分の負荷率を自動演算し求める。
なんらかの理由で、所望の減速時間内で過負荷保護停止することなしに、確実に減速させたい場合に有効である。
【００３０】
（第５の実施形態）
次に、本発明の第５の実施形態に係る電動機駆動装置について説明する。
図６に第５の実施形態の主要部の構成を示す。
【００３１】
本実施形態は、図１の負荷率判定回路１２の出力を速度基準変化率制限値信号ｂとしたもので、変化率制限値信号ｂを変化率制限回路１に印加することで、加速完了直後等で負荷率が大きいときに加減速操作された場合、負荷率が過負荷保護停止範囲に入らない程度の加減速変化率で速度を変更する。負荷特性によって、図６に示す特性の負荷率判定に代えて、第１の実施形態から第４の実施形態のどの負荷率判定を適用しても良い。
【００３２】
このように、この実施形態においては、負荷率演算値を監視しその時々の負荷率に応じて過負荷保護停止にならないように速度基準変化率制限をすることで過負荷保護停止することなしに安定に運転を継続できるように構成している。
【００３３】
即ち、加減速中の過負荷状態であれば、負荷率演算値が大きくなったら速度基準の変化率を小さくし負荷率演算値を減少させ、負荷率演算値に余裕ができたら速度基準の変化率を大きくしている。
【００３４】
（第６の実施形態）
次に、本発明の第６の実施形態に係る電動機駆動装置について説明する。
図７に第６の実施形態の主要部の構成を示す。
【００３５】
本実施形態は図１の負荷率判定回路１２に入力する負荷率値ｕを通常の負荷率演算回路９の出力ｎに停止予測負荷率演算値ｓを加算器１６で加算し被判定値ｕとし、負荷率判定回路１２の出力を変化率制限値信号ｂとして変化率制限回路１に印加するものである。停止予測負荷率演算値ｓは、現在速度ｊと任意に与えられる停止時間（または任意の速度に至るまでの時間）ｖから停止まで（または任意の速度に至るまで）に必要とする回生電流成分の負荷率を停止予測負荷率演算回路１７で自動演算し求める。
本実施形態は、過負荷保護停止することなしに所望の減速時間内で確実に減速させたい場合に有効である。
【００３６】
（第７の実施形態）
次に、本発明の第７の実施形態に係る電動機駆動装置について説明する。
第７の実施形態の主要部の構成を図８に示す。
【００３７】
この第７の実施形態は、電動機駆動装置を複数台使用して抄紙機ラインを構成した場合、各電動機駆動装置Ｄ１、Ｄ２、…、Ｄ＊に対する速度変化率制限値信号ｂ１、ｂ２、…、ｂ＊の中から最小の値を最小値選択回路１８で自動選択して得た変化率制限値信号ｂ（ｂ＝ｍｉｎ（ｂ１〜ｂ＊））により、変化率制限回路１００で、大元となるライン速度基準の変化率に制限を加えるように構成したものである。なお、図８において１９１、１９２、…、１９＊は各電動機駆動装置Ｄ１、Ｄ２、…、Ｄ＊間の速度を微調整する速度設定器である。
【００３８】
これは、搬送材である紙がワイヤーセクションから巻取りリールセクションまで通った状態で操業しているときにいずれか１つ以上のセクションの電動機が過負荷状態になり電動機が保護停止し、または本発明の他の実施形態にあるような電流制限あるいは速度変化率制限が電動機駆動装置個別に働いた場合、他の過負荷状態でない電動機より速度の低下または速度基準変化中であれば速度基準変化率に差が生じ、それらの度合いによっては断紙する場合がある。そこで、完全通紙の連続操業状態においても過負荷保護停止しないようにするため過負荷が最も大きい電動機駆動装置より得られる速度変化率制限値信号ｂによってライン全体の速度基準の変化率を制限し、ライン全体を加速した場合でも全電動機の速度変化率を一定にでき安定な操業ができるようにしたものである。
【００３９】
（第８の実施形態）
次に、本発明の第８の実施形態に係る電動機駆動装置について説明する。
第８の実施形態の主要部の構成を図９に示す。
【００４０】
この第８の実施形態は、図１に対してマンーマシンインタフェースを具備した構成である。
前述までの実施形態にある過負荷保護停止防止運転では負荷率演算値ｎによって自動的に電流制限あるいは速度変化率制限が働くが、ベアリンググリス切れ等で注油さえすれば良い場合など過負荷原因によっては機械への簡単な処置により過負荷状態を回避できる場合がある。定常操業時に自動的に電流制限が働くと運転速度が低下し、セクション間の速度差が変動し断紙する危険がある。
【００４１】
そこで、負荷率演算値ｎがある値以上になったら視覚や聴覚に訴える警報を操業員に与える、且つまたは現在の負荷率演算値の変化量を求め電流制限が開始されるまでの残り時間を表示し、あるいは残り警告時間と残り時間を比較し、残り時間が残り警告時間以下になったら更に警告を与えるようにマンーマシンインタフェースを用いて報知を行うこととしたものである。
【００４２】
即ち、図９においては、負荷率変化検出回路２０で現在の負荷率演算値ｎの変化量Ｙ２（Ｙ２＝ｄｎ／ｄｔ）を求めるとともに、減算器２１で負荷率判定値ｑ１と負荷率演算値ｎとの差Ｙ１を求め、残り時間演算回路２２でこれらＹ１、Ｙ２より速度基準変化率制限開始までの時間ｔ_R を求め、これをマンーマシンインタフェース２３によって報知するようにしている。
以上のように構成することで、過負荷保護停止または電流制限による減速を未然に防ぎ得る操業が可能である。
【００４３】
（第９の実施形態）
次に、本発明の第９の実施形態に係る電動機駆動装置について説明する。
第９の実施形態の主要部の構成を図１０に示す。
【００４４】
この第７の実施形態は、図１に対してマンーマシンインタフェースを具備した構成である。
現在の操業条件（時刻情報、銘柄、坪量、速度、周囲温度、ドライヤ蒸気温度、ドライヤ蒸気圧力、修繕からの累積運転時間、修繕からの累積搬送長のいづれか１つ以上の組合わせ）を、データ格納装置に格納し、現在抄造している銘柄、坪量、速度の少なくとも１つ以上の検索条件から運転中の負荷率偏差を求め、異常判定を行い、異常の偏差が生じたときその操業条件の違いを抽出し、操業員に視覚的に情報を提供できるように構成する。
【００４５】
即ち、図１０においては、現在の操業条件ｆをデータ格納装置２５に格納し、現在抄造している銘柄、坪量、速度の少なくとも１つ以上の検索条件を選択回路２７で選択して、データベース２６から現在抄造しているものと同等のものの過去の操業条件を読み出し、比較回路２８で現在の操業条件と比較して偏差を求め、報知装置２９に表示するとともに、異常判定回路３０で許容偏差ｗを越えていれば異常判定回路３０からアラーム情報ＡＬＭを出力してこれを報知装置２９で報知するようにしている。
【００４６】
以上のように構成することで、異常負荷の原因究明を早期に行うことができ、過負荷保護停止または電流制限による減速を未然に防ぎ得る操業が可能である。尚、以上の各実施形態で挙げた個々の演算、判定機能を行う部分は、一般の電動機駆動装置の内部に設けても、外部に付加して設けても、同様の作用をするのであればどちらでもよい。また、電動機としては、直流機、交流機両方に適用できる。
【００４７】
【発明の効果】
以上説明したように、本発明に係る電動機駆動装置によれば、負荷容量が充分でない場合でも過負荷保護停止に陥ることなく、過負荷保護範囲内で電動機容量を有効に引き出し、安定な操業が可能となる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図２】第１の実施形態における負荷率判定回路の動作特性を示す図。
【図３】第２の実施形態における負荷率判定回路の動作特性を示す図。
【図４】本発明の第３の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図５】本発明の第４の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図６】本発明の第５の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図７】本発明の第６の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図８】本発明の第７の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図９】本発明の第８の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図１０】本発明の第９の実施形態に係る電動機駆動装置の主要部の構成を示すブロック図。
【図１１】従来の電動機駆動装置の主要部の構成を示すブロック図。
【図１２】従来の電動機駆動装置における負荷率演算回路の構成を示すブロック図。
【符号の説明】
１…変化率制限回路
２…速度制御回路
３…電流制御回路
４…電流制限回路
５…電力変換回路
６…電流検出器
７…電動機
８…速度検出器
９…負荷率演算回路
１０…保護判定回路
１２…負荷率判定回路
１３…負荷率変化検出回路
１４…関数発生器
１５、１６…加算器
１７…停止予測負荷率演算回路
１８…最小値選択回路
１００…変化率制限回路
１９１、１９２、…、１９＊…速度設定器
Ｄ１、Ｄ２、…、Ｄ＊…電動機駆動装置
２０…負荷率変化検出回路
２１…減算器
２２…残り時間演算回路
２３…マンーマシンインタフェース
２５…データ格納装置
２６…データベース
２７…選択回路
２８…比較回路
２９…報知装置
３０…異常判定回路
９１…乗算器
９２…移動平均出力回路
９３…スタック
９４…加算回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor for driving a paper machine capable of continuous operation with the maximum capacity of the apparatus or the motor without stopping overload protection.
[0002]
[Prior art]
FIG. 11 shows a configuration of a main part of a conventional electric motor drive device which is an example of an application target of the present invention. In the figure, 1 is a change rate limiting circuit that limits the rate of change of the speed setting value signal a by the rate of change limit value signal b and outputs a speed reference signal c, 2 is a speed control circuit, and 3 is a first current command signal. a current control circuit for outputting i, a current limiting circuit for limiting an input current command signal i by a current limit value signal r and outputting a second current command signal h, 5 for a power conversion circuit, and 7 for paper An electric motor 6 connected directly to a transport roll of a paper machine to be continuously made through a speed reducer, or 6 is a current detector that detects a current l between the power conversion circuit 5 and the motor 7 and outputs a current feedback signal m. , 8 is a speed detector that detects the speed of the motor and outputs a speed feedback signal j, 9 is a load factor calculation circuit that calculates the load factor and outputs a load factor calculation value signal n, and 10 is a load factor calculation value signal n The protection judgment value signal o is compared in magnitude and the protection command signal p is A protection determination circuitry to force. In this motor drive device, the limit values of the change rate limit value signal b and the current limit value signal r are set to fixed values.
[0003]
In this motor drive device, in order to prevent the motor 7 from being destroyed by overheating, the load factor calculation circuit 9 calculates the load factor n from the current value l detected by the current detector 6, and the value n is the protection limit. When the judgment value o is reached, the protection judgment circuit 10 outputs a protection command signal p for cutting off the power supply to the motor 7 or the regenerative power from the motor 7 to the power conversion circuit 5 to supply the power to the motor 7 and regenerate it. The electric motor 7 is protected by interrupting the current and rotating it by inertia.
[0004]
The part called current control may be called torque control that is proportional to the electric motor 7. In addition, this electric motor drive device may be a DC motor drive device or an AC motor drive device.
[0005]
Here, there are various calculation methods for calculating the load factor n. As an example, FIG. 12 shows a method using an effective current value per unit time. The current value l detected every minute time detected by the current detector 6 is squared by the multiplier 91, accumulated as an absolute value for a unit time by the moving average output circuit 92, and the moving average is taken and stored in the stack 93. This is added for the target protection time by the adder circuit 94 to obtain a load factor value n per target time (for example, 5 minutes). A warning value and a limit value within the rated range are calculated in advance from the rated value of the electric motor 7 and stored as determination constants. The protection determination circuit 10 compares the calculation result n with the determination constant o, and when the calculation result exceeds the warning value, an overload alarm signal is output. If the overload remains unchanged, the calculation value exceeds the limit value. At that time, the power converter circuit 5 is shut off and the output power line is shut off, and the motor 7 is stopped by inertia.
[0006]
[Problems to be solved by the invention]
In the paper making line, there are cases where speed-up remodeling for the purpose of increasing production is performed. At this time, the capacity of the electric motor drive device may not be increased and the electric motor having a larger capacity cannot be updated depending on the capital investment capacity. In this way, during the operation of the motor drive device or the motor with insufficient capacity, various types of motion such as grease deterioration of each moving part, drain accumulation inside the dryer due to excessive steam, repeated acceleration and deceleration operations at short intervals, etc. The motor tends to stop overload protection due to overload factors. Once the overload protection is stopped, it is necessary to inspect the inside of the motor drive unit, check the surroundings of the machine, identify the cause of the overload, and take countermeasures to restart, especially when the motor speed is relatively high. When stopped, rolls with a large moment of inertia take a long time to stop. Reduced production due to the waiting time until the stoppage and the stoppage time of the paper making line for inspection, cause investigation, and countermeasures become a problem.
[0007]
The present invention has been made in view of the above points, and is an electric motor drive device for a paper machine that can stably operate without stopping overload protection and can reduce loss time due to operation overload protection stoppage. The purpose is to provide.
[0008]
[Means for Solving the Problems]
An electric motor drive device for a paper machine according to the present invention includes an electric motor connected via a speed reducer or directly to a transport roll of a paper machine for continuously making paper, a means for driving the electric motor, and a load factor of the electric motor Calculation means for calculating a calculation value, and a current for generating a predetermined current limit value signal for limiting the current command value when the load factor calculation value obtained by this means becomes a predetermined value lower than the load ratio at which protection is stopped And a limit value signal generating means, so that the motor can be continuously operated without protection stop even during overload operation.
[0009]
By adopting such a configuration, the electric motor can be continuously operated without stopping overload protection, so that loss time due to occurrence of stoppage of overload protection can be reduced.
Here, the current limit value signal generating means may generate a current limit value signal having hysteresis characteristics in the current limit start load factor and the current limit open load factor when generating the current limit value signal.
[0010]
Such a configuration is effective when the frequency of acceleration / deceleration operations is large because the load factor calculation value can be given a margin at the time of the operation at the time of reacceleration or deceleration after acceleration.
[0011]
Further, the current limit value signal generating means includes means for predicting a future load factor from a past load factor calculation value and a current load factor, and the load factor calculation value obtained by this means is a load factor at which protection is stopped. A predetermined current limit value signal for limiting the current command value may be generated when the predetermined value becomes lower.
[0012]
Such a configuration is effective when the response of the load factor calculation is slow and the load factor calculation value still increases even when the current is limited due to the influence.
Further, the present invention, instead of limit value signal generating means for generating a predetermined current limit value signal for limiting the current command value when the load factor calculation value becomes a predetermined value lower than the load factor at which protection is stopped, And a change rate limit value signal generating means for generating a predetermined change rate limit value signal for limiting the change rate of the speed reference command when the load factor calculation value becomes a predetermined value lower than the load rate at which the protection is stopped. It is good.
[0013]
Even with such a configuration, the electric motor can be continuously operated without stopping overload protection, and therefore, loss time due to occurrence of overload protection stop can be reduced.
The current limit value signal generating means or the change rate limit value signal generating means is a load factor obtained by adding a current load factor and a load factor required for a set stop time or a time required to reach a set speed. Generates a predetermined current limit value signal that limits the current command value or a predetermined change rate limit value signal that limits the rate of change of the speed reference command when the load value becomes lower than the load rate at which protection is stopped. It may be a thing.
[0014]
Such a configuration is effective when it is desired to reliably decelerate within a desired deceleration time without stopping overload protection.
Furthermore, the present invention provides a paper machine motor drive device that uses a plurality of such paper machine motor drive devices to form a paper machine line, and the change rate limit value signal obtained from each motor drive device is limited. Means for selecting a change rate limit value signal whose limit value is the minimum value among the values, and means for limiting the rate of change of the speed reference of the paper machine line by the speed reference change rate limit value signal of the selected minimum value; It is characterized by comprising.
[0015]
By adopting such a configuration, the speed change rate of the entire line is limited by the speed change rate limit value obtained from the motor drive device with the largest overload even in the continuous operation state of complete paper passing. Even when accelerating, the speed change rate of all motors can be kept constant and stable operation can be achieved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in the following drawings, the same reference numerals, including FIG. 11 and FIG.
[0017]
(First embodiment)
This embodiment monitors the load factor calculation value and limits the current so as not to stop overload protection according to the load factor at that time so that the operation can be stably continued without stopping overload protection. The device is configured.
[0018]
FIG. 1 shows the configuration of the main part of an electric motor drive device according to the first embodiment of the present invention. In the same figure, the part shown with the code | symbol 1 to the code | symbol 10 is the same structure as the thing of FIG. 11 demonstrated as a conventional motor drive device. A load factor determination 12 calculates the current limit value r by comparing the load factor calculated value n with a certain value q within the overload protection value range (that is, a value lower than the load factor at which protection is stopped). Circuit.
[0019]
The operating characteristics of the load factor determination circuit 12 are shown in FIG.
When the load factor calculation value n is smaller than the load factor determination value q, a current limit value signal r of 100% or more (eg, 150%) is output, and a current limit value signal r of q or more and 100% or less (eg, 80%) is output. Is output. This current limit value signal r is supplied to the current limit circuit 4.
[0020]
In this way, when the load factor calculation value n exceeds a certain value q within the overload protection value range, the current limit circuit 4 increases the current command limit so as to reduce the current flowing through the motor 7, and the load factor calculation value n. The electric motor 7 is operated so as to decrease. When the load factor calculation value n has a margin, the current limit is weakened and the electric motor 7 is operated.
[0021]
As a load situation to which the present embodiment can be applied, although it is possible to accelerate even when the motor capacity is 100% or less, it is effective in the case of a paper machine motor that is planned to have a large desired acceleration.
[0022]
According to the motor drive device configured as described above, since continuous operation can be performed without stopping overload protection, a paper machine motor drive device that can reduce loss time due to occurrence of overload protection stop can be configured.
[0023]
(Second Embodiment)
Next, an electric motor drive device according to a second embodiment of the present invention will be described.
The configuration of the second embodiment may be the same as that shown in FIG. 1, but is a configuration in which determination conditions are increased in the load factor determination circuit 12 of FIG.
[0024]
FIG. 3 shows the operating characteristics of the load factor determination circuit 12.
The load factor determination circuit 12 outputs a current limit value signal r of 100% or more at the initial stage of operation, but the load factor calculation value n is based on the second load factor determination value (that is, the current limit start load factor determination value) q2. When a current limit value signal r of 100% or less is output within a large range and the load factor calculation value n decreases to a first load factor judgment value (that is, a current limit open load factor judgment value) q1 smaller than q2, it is 100% or more. The determination is made to have a hysteresis characteristic so as to output the current limit value signal r.
[0025]
As a load situation to which this embodiment can be applied, acceleration is possible even when the motor capacity is 100% or less, but it is effective when the desired acceleration is planned to be large and the frequency of acceleration / deceleration operations is large. In other words, when re-acceleration or deceleration after acceleration, an allowance is provided for the load factor calculation value at the time of the operation.
[0026]
(Third embodiment)
Next, an electric motor driving device according to a third embodiment of the present invention will be described.
In the present embodiment, a future load factor is predicted from a past load factor and a current load factor, and this load factor calculation value is monitored.
[0027]
FIG. 4 shows the configuration of the main part of the third embodiment.
In the present embodiment, a load factor change detection circuit 13 that calculates a change rate z of the load factor n on the input side of the load factor determination circuit 12 in FIG. 1 and an overload caused by a response delay of the load factor arithmetic circuit 9 with respect to the change rate z. In order to predict the shoot, a function generator 14 for calculating the overshoot predicted load factor k and an adder 15 for adding the overshoot predicted load factor k to the load factor calculated value n output from the load factor calculation circuit 9 are added. The output u of the adder 15 is input to the load factor determination circuit 12.
[0028]
The present embodiment is effective when the load factor calculation response of the load factor calculation circuit 9 is slow, and the load factor calculation value still increases even when the current limit is applied due to the influence. Depending on the characteristics of the load, the load factor determination circuit 12 may select either one having a hysteresis characteristic as shown in FIG. 3 or one having no hysteresis characteristic as shown in FIG.
[0029]
(Fourth embodiment)
Next, an electric motor drive device according to a fourth embodiment of the present invention will be described.
FIG. 5 shows the configuration of the main part of the fourth embodiment.
In the present embodiment, the load factor value input to the load factor determination circuit 12 in FIG. 1 is a value u obtained by adding the stop predicted load factor calculation value s by the adder 16 to the output n of the normal load factor calculation circuit 9. The predicted stop load factor calculation value s is the regeneration required from the current speed j and the arbitrarily given stop time (or time to reach any speed) v to the stop (or to reach any speed). The load factor of the current component is automatically calculated and obtained.
This is effective when it is desired to decelerate reliably without stopping the overload protection within a desired deceleration time for some reason.
[0030]
(Fifth embodiment)
Next, an electric motor drive device according to a fifth embodiment of the present invention will be described.
FIG. 6 shows the configuration of the main part of the fifth embodiment.
[0031]
In the present embodiment, the output of the load factor determination circuit 12 in FIG. 1 is a speed reference change rate limit value signal b. By applying the change rate limit value signal b to the change rate limit circuit 1, immediately after completion of acceleration. If the acceleration / deceleration operation is performed when the load factor is large, etc., the speed is changed at an acceleration / deceleration change rate that does not enter the overload protection stop range. Depending on the load characteristics, any load factor determination of the first to fourth embodiments may be applied instead of the load factor determination of the characteristics shown in FIG.
[0032]
Thus, in this embodiment, without overload protection being stopped by monitoring the load factor calculation value and limiting the speed reference change rate so as not to stop overload protection according to the load factor at that time. It is configured so that operation can be continued stably.
[0033]
In other words, if the load factor calculation value increases, the speed reference change rate decreases and the load factor calculation value decreases when the load factor calculation value increases, and if the load factor calculation value has room, the speed reference change changes. The rate is increasing.
[0034]
(Sixth embodiment)
Next, an electric motor drive device according to a sixth embodiment of the present invention will be described.
FIG. 7 shows the configuration of the main part of the sixth embodiment.
[0035]
In the present embodiment, the load factor value u input to the load factor determination circuit 12 of FIG. 1 is added to the output n of the normal load factor calculation circuit 9 by the adder 16 and the predicted stop load factor calculation value s is added to obtain the determined value u. The output of the load factor determination circuit 12 is applied to the change rate limiting circuit 1 as the change rate limiting value signal b. The predicted stop load factor calculation value s is a regenerative current component required from the current speed j to an arbitrarily given stop time (or time to reach an arbitrary speed) v to stop (or to an arbitrary speed). Is automatically calculated by the stop predicted load factor calculation circuit 17.
This embodiment is effective when it is desired to reliably decelerate within a desired deceleration time without stopping overload protection.
[0036]
(Seventh embodiment)
Next, an electric motor driving device according to a seventh embodiment of the present invention will be described.
The configuration of the main part of the seventh embodiment is shown in FIG.
[0037]
In the seventh embodiment, when a paper machine line is configured by using a plurality of motor drive devices, speed change rate limit value signals b1, b2,... For each motor drive device D1, D2,. The change rate limiting circuit 100 uses the change rate limit value signal b (b = min (b1 to b *)) obtained by automatically selecting the minimum value from b * by the minimum value selection circuit 18 to The line speed reference change rate is configured to be limited. In FIG. 8, reference numerals 191, 192,..., 19 * denote speed setting devices for finely adjusting the speed between the motor driving devices D 1, D 2,.
[0038]
This is because when the transport paper is running from the wire section to the take-up reel section, the motor in one or more sections will be overloaded and the motor will stop protection, When current limitation or speed change rate limitation as in another embodiment of the invention is applied to each motor drive device, the speed reference change rate is lower than the other non-overloaded motor or during speed reference change. Depending on the degree, the paper may be cut off. Therefore, in order to prevent overload protection from being stopped even in the continuous operation state where the paper is completely passed, the speed reference change rate of the entire line is limited by the speed change rate limit value signal b obtained from the motor drive device having the largest overload. Even when the entire line is accelerated, the speed change rate of all motors can be kept constant so that stable operation can be achieved.
[0039]
(Eighth embodiment)
Next, an electric motor drive device according to an eighth embodiment of the present invention will be described.
FIG. 9 shows the configuration of the main part of the eighth embodiment.
[0040]
The eighth embodiment has a configuration including a man-machine interface with respect to FIG.
In the overload protection stop prevention operation in the above-described embodiments, the current limit or the speed change rate limit is automatically activated by the load factor calculation value n. However, depending on the cause of the overload, such as when it is sufficient to lubricate the bearing grease, etc. May be able to avoid overload conditions with a simple action on the machine. If the current limit is automatically activated during steady operation, the operation speed decreases, and there is a risk that the speed difference between sections fluctuates and the paper is cut.
[0041]
Therefore, when the load factor calculation value n exceeds a certain value, an alarm that appeals to the sight and hearing is given to the operator, and / or the amount of change in the current load factor calculation value is obtained and the remaining time until the current limit is started. Display or compare the remaining warning time with the remaining time, and when the remaining time is less than or equal to the remaining warning time, notification is performed using the man-machine interface so as to give further warning.
[0042]
That is, in FIG. 9, the load factor change detection circuit 20 obtains the change amount Y2 (Y2 = dn / dt) of the current load factor calculation value n, and the subtractor 21 calculates the load factor determination value q1 and the load factor calculation value. The difference Y1 from n is obtained, and the remaining time calculation circuit 22 obtains the time t _R from Y1 and Y2 until the speed reference change rate restriction start, and this is notified by the man-machine interface 23.
By configuring as described above, it is possible to perform an operation that can prevent overload protection stop or deceleration due to current limitation.
[0043]
(Ninth embodiment)
Next, an electric motor drive device according to a ninth embodiment of the present invention will be described.
FIG. 10 shows the configuration of the main part of the ninth embodiment.
[0044]
The seventh embodiment has a man-machine interface with respect to FIG.
Current operating conditions (time information, brand, basis weight, speed, ambient temperature, dryer steam temperature, dryer steam pressure, cumulative operation time from repair, cumulative transport length from repair or combination of one or more) The load factor deviation during operation is obtained from at least one of the search conditions of the brand, basis weight, and speed currently stored in the data storage device, the abnormality is judged, and the operation is performed when an abnormality deviation occurs. It is configured so that differences in conditions can be extracted and information can be provided visually to operators.
[0045]
That is, in FIG. 10, the current operating condition f is stored in the data storage device 25, and at least one search condition of the brand, basis weight, and speed currently being produced is selected by the selection circuit 27, and the database 26, a past operation condition equivalent to that currently produced is read out, a comparison circuit 28 compares the current operation condition with the current operation condition, and a deviation is obtained and displayed on the notification device 29. If it exceeds w, the alarm information ALM is output from the abnormality determination circuit 30 and this is notified by the notification device 29.
[0046]
By configuring as described above, the cause of the abnormal load can be investigated at an early stage, and operation capable of preventing deceleration due to overload protection stop or current limitation can be performed. In addition, if the part which performs each calculation and determination function quoted in each of the above embodiments is provided inside a general electric motor drive device or provided externally, the same function can be used. either will do. Moreover, it can apply to both a DC machine and an AC machine as an electric motor.
[0047]
【The invention's effect】
As described above, according to the motor drive device of the present invention, even when the load capacity is not sufficient, the motor capacity is effectively extracted within the overload protection range without causing the overload protection stop, and stable operation is achieved. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a main part of an electric motor drive device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing operating characteristics of a load factor determination circuit according to the first embodiment.
FIG. 3 is a diagram showing operating characteristics of a load factor determination circuit according to a second embodiment.
FIG. 4 is a block diagram showing a configuration of a main part of an electric motor drive device according to a third embodiment of the present invention.
FIG. 5 is a block diagram showing a configuration of a main part of an electric motor drive device according to a fourth embodiment of the present invention.
FIG. 6 is a block diagram showing a configuration of a main part of an electric motor drive device according to a fifth embodiment of the present invention.
FIG. 7 is a block diagram showing a configuration of a main part of an electric motor drive device according to a sixth embodiment of the present invention.
FIG. 8 is a block diagram showing a configuration of a main part of an electric motor drive device according to a seventh embodiment of the present invention.
FIG. 9 is a block diagram showing a configuration of a main part of an electric motor drive device according to an eighth embodiment of the present invention.
FIG. 10 is a block diagram showing a configuration of a main part of an electric motor drive device according to a ninth embodiment of the present invention.
FIG. 11 is a block diagram showing a configuration of a main part of a conventional electric motor drive device.
FIG. 12 is a block diagram showing a configuration of a load factor calculation circuit in a conventional electric motor drive device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Change rate limiting circuit 2 ... Speed control circuit 3 ... Current control circuit 4 ... Current limiting circuit 5 ... Power conversion circuit 6 ... Current detector 7 ... Electric motor 8 ... Speed detector 9 ... Load factor calculation circuit 10 ... Protection judgment circuit DESCRIPTION OF SYMBOLS 12 ... Load factor determination circuit 13 ... Load factor change detection circuit 14 ... Function generator 15, 16 ... Adder 17 ... Stop prediction load factor calculation circuit 18 ... Minimum value selection circuit 100 ... Change rate limitation circuit 191, 192, ... 19 * ... speed setting devices D1, D2,..., D * ... motor drive device 20 ... load factor change detection circuit 21 ... subtractor 22 ... remaining time calculation circuit 23 ... man-machine interface 25 ... data storage device 26 ... database 27 ... Selection circuit 28 ... Comparison circuit 29 ... Notification device 30 ... Abnormality determination circuit 91 ... Multiplier 92 ... Moving average output circuit 93 ... Stack 94 ... Addition circuit

Claims

An electric motor connected via a speed reducer or directly to a transport roll of a paper machine for continuously making paper, a means for driving the electric motor, an arithmetic means for calculating a load factor calculation value based on the electric current of the electric motor, and When the load factor calculation value obtained by the means becomes a predetermined value lower than the load factor at which protection is stopped, a predetermined current limit value signal for limiting the current command value is generated , and the current limit value signal is Current limit value signal generating means having a hysteresis characteristic in the starting load factor and the current limit open load factor is provided so that the motor can be continuously operated without being stopped during overload operation. An electric motor drive device for a paper machine.

The current limit value signal generating means includes means for predicting a future load factor from a past load factor calculation value and a current load factor, and a load factor calculation value obtained by this means is based on a load factor at which protection is stopped. 2. The electric motor drive device for a paper machine according to claim 1, wherein a predetermined current limit value signal for limiting a current command value is generated when a low predetermined value is reached .

An electric motor connected via a speed reducer or directly to a transport roll of a paper machine for continuously making paper, a means for driving the electric motor, an arithmetic means for calculating a load factor calculation value based on the electric current of the electric motor, and A means for predicting the future load factor from the current load factor calculation value obtained by the means and the past load factor calculation value, and the predicted load factor calculation value obtained by this means is added to the current load factor calculation value. Current limit value signal generating means for generating a predetermined current limit value signal for limiting the current command value when the load ratio becomes a predetermined value lower than the load ratio at which the protection is stopped. An electric motor driving device for a paper machine, which is capable of continuous operation without stopping protection even during load operation.

An electric motor connected via a speed reducer or directly to a transport roll of a paper machine for continuously making paper, a means for driving the electric motor, an arithmetic means for calculating a load factor calculation value based on the electric current of the electric motor, and Change rate limit value signal generation that generates a predetermined change rate limit value signal that limits the rate of change of the speed reference command when the load factor calculation value obtained by the means becomes a predetermined value lower than the load rate at which protection is stopped And an electric motor driving device for a paper machine, wherein the electric motor is capable of continuous operation without stopping protection even during overload operation.

The rate-of-change limit value signal generating means includes a predetermined value that is lower than the load factor at which the current load factor and the load factor required for the time until the set speed are reached are lower than the load factor at which protection is stopped. 5. The electric motor drive device for a paper machine according to claim 4 , wherein a predetermined rate-of-change limit value signal for limiting the rate of change of the speed reference command is generated.

5. A paper machine motor drive device comprising a plurality of paper machine motor drive devices as claimed in claim 4, wherein a change rate limit value signal obtained from each motor drive device is limited. Means for selecting a change rate limit value signal whose value is the minimum value, and means for limiting the rate of change of the speed reference of the paper machine line by the speed reference change rate limit value signal of the selected minimum value. An electric motor drive device for a paper machine.

An electric motor connected via a speed reducer or directly to a transport roll of a paper machine for continuously making paper, means for driving the electric motor, and arithmetic means for obtaining a current load factor calculation value based on the electric current of the electric motor; A means for predicting the load factor required from the current speed and the set stop time to the stop, and a load factor obtained by adding the stop predicted load factor calculation value obtained by this means to the current load factor calculation value. Current limit value signal generating means for generating a predetermined current command value signal for limiting the current command value when the predetermined value is lower than the load ratio at which protection is stopped, and the motor is in overload operation. A motor drive device for a paper machine, characterized in that continuous operation is possible without stopping protection.