JP2004023804A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a spatial harmonic of inductance of a motor. <P>SOLUTION: The motor controller includes: a fundamental wave current controlling circuit 100 for controlling a fundamental wave current of a three-phase AC motor M in dq axis coordinate system, made up of d axis and q axis, synchronized with rotation of the motor M; a harmonic current controlling circuit 200 for controlling a harmonic current of the motor M to 0 in dhqh axis coordinating system, made up of dh axis and qh axis, rotating at a frequency as an integral multiple of a fundamental wave factor of a current in the motor M; and a spatial harmonic wave processor 10 for calculating a spacial harmonic wave of inductance of the motor M on the basis of a current of dq axis coordinate system and a rotational speed of the motor M. <P>COPYRIGHT: (C)2004,JPO

Description

【００１３】
図２は、高調波電流の３相交流座標における次数ｍとｄｑ軸座標における次数ｋとの関係を示す表である。例えば、３相交流座標にて５次高調波電流をｄｑ座標系に変換した場合、ｋ＝−６（＝−５−１）より、−６次高調波電流となる。
【００１４】
電流センサ２２，２３は、３相交流モータＭのＵ相とＶ相の実電流ｉｕ，ｉｖを検出する。３相／ｄｑ変換部５は、基本波電流位相θｅに基づいて、３相交流モータＭの実電流ｉｕ，ｉｖ，ｉｗ（＝−ｉｕ−ｉｖ）をｄ軸とｑ軸の実電流ｉｄ，ｉｑへ変換する。
【００１５】
高調波電流制御回路は、ハイパス・フィルタ６、ｄｑ／ｄｈｑｈ変換部７、ＰＩ−ｄｈｑｈ電流制御器８、ｄｈｑｈ／３相変換部９、空間高調波演算器１０、記憶装置１１および加算器２０，２１を備えている。ハイパス・フィルタ６は、ｄ軸，ｑ軸の実電流ｉｄ，ｉｑにフィルタ処理を施して高周波成分を抽出する。ｄｑ／ｄｈｑｈ変換部７は、上述した基本波電流制御回路のみでモータ電流ｉｕ，ｉｖ，ｉｗを制御した場合に発生する所定次数の高調波成分の周波数で回転する直交座標系（高調波座標系）ｄｈｑｈを有し、ｄ軸，ｑ軸の実電流ｉｄ，ｉｑの高周波成分をそれぞれ、高調波座標系ｄｈｑｈの実電流ｉｄｈ，ｉｑｈに変換する。
【００１６】
減算器２０，２１は、ｄｈ軸とｑｈ軸の実電流ｉｄｈ，ｉｑｈと、電流指令値ｉｄｈ^＊，ｉｑｈ^＊との差を算出する。ＰＩ−ｄｈｑｈ電流制御器８は、減算器２０，２１によって減算された結果に基づいて、ｄｈ軸とｑｈ軸の高調波電圧指令値ｖｄｈ^＊，ｖｑｈ^＊を演算する。ｄｈｄｑ／３相変換部９は、ｄｈ軸高調波電圧指令値ｖｄｈ^＊およびとｑｈ軸高調波電圧指令値ｖｑｈ^＊をそれぞれ３相交流電圧指令値ｖｄ’，ｖｑ’に変換する。ｄｈｄｑ／３相変換部９で変換された３相交流電圧指令値ｖｄ’，ｖｑ’は、加算器１７，１８，１９にそれぞれ出力される。
【００１７】
空間高調波演算器１０は、ｄ軸，ｑ軸の実電流ｉｄ，ｉｑ、モータＭの電気的角速度ω、ＰＩ−ｄｑ電流制御器８で算出された高調波電圧指令値ｖｄｈ^＊，ｖｑｈ^＊に基づいて、モータＭのインダクタンスの空間高調波Ｌ２を算出する。インダクタンスの空間高調波Ｌ２の算出方法は後述する。算出されたインダクタンスの空間高調波Ｌ２は、記憶装置１１に記憶される。
【００１８】
同期モータの高調波電流発生の要因としては、インダクタンスの空間高調波と磁石磁束の高調波などが考えられる。埋込型永久磁石（ＩＰＭ）モータの場合、理想的には３相での自己インダクタンスは、図２に示すように、位相に対して正弦波で変化する。ＩＰＭモータのロータの形状などによっては、図３に示すように、インダクタンスが位相に対して歪みを持つ正弦波で変化し、このような歪み（空間高調波）が高調波電流の発生要因となる。以下では、インダクタンスの空間高調波について座標変換を行い、ｄｑ座標系とｄｈｑｈ座標系での回路方程式を導く。
【００１９】
３相交流における自己インダクタンスＬｕ，Ｌｖ，Ｌｗは、空間高調波を考慮に入れると、次式（２）のように表せる。

…（２）
【００２０】
上式（１）において、Ｌｏは３相同期モータＭのインダクタンスの直流分、Ｌｎ（ｎ＝１，２，…）はモータＭのインダクタンスの交流分、θｅはモータＭの電気角を表す。式（１）において、ｎ＝１の場合には、右辺第２項は一般的な内部埋め込み磁石構造を有するＩＰＭモータの突極性を表す項となり、ｎ≧２の場合の各相の自己インダクタンスＬｕ，Ｌｖ，Ｌｗの高調波成分が高調波速度起電力の発生要因となる。
【００２１】
一般的なＩＰＭモータでは、ｄ軸インダクタンスＬｄおよびｑ軸インダクタンスＬｑは、Ｌ_０とＬ_１を用いて、それぞれ次式（３），（４）で表される。

【００２２】
ｄ軸、ｑ軸インダクタンスを用いて表される一般的なＩＰＭモータのｄｑ座標回路方程式は、次式（５）で表される。ただし、ＲはモータＭの電機子抵抗、ωはモータＭの電気的角速度、ｐは微分演算子を表している。また、φは磁石磁束による誘起電圧定数である。

【００２３】
インダクタンスの空間高調波を表すｎ≧２の成分については、ｎの場合分けにより、次式（６），（７）の各項が式（５）の右辺に加わる形になる。
・ｎ＝１，４，７・・・の場合

…（６）
・ｎ＝２，５，８・・・の場合

…（７）
【００２４】
インダクタンスの空間高調波が高調波速度起電力として働き、これをｄｈｑｈ座標へ座標変換する際に、高調波の次数をインダクタンスの空間高調波の次数ｎを用いて位相θｅｈを求めると、これらの空間高調波は簡単な直流量として表すことができる。空間高調波は各次数ｎの和として表しているが、ここでは、そのうちの一つを取り出して表す。
・ｎ＝１，４，７・・・の場合
ｄｈｑｈ座標変換の変換に位相θ_ｅｈ＝（２ｎ−２）θ_ｅを用いて式（６）を変換すると、

となる。
・ｎ＝２，５，８・・・の場合
ｄｈｑｈ座標変換の変換に位相θ_ｅｈ＝−（２ｎ＋２）θ_ｅを用いて式（７）を変換すると、

となる。
【００２５】
ｄｑ座標系における回路方程式をｄｈｑｈ座標系の回路方程式として表すと、次式（１０）のようになる。ただし、式（１０）で表される回路方程式では、空間高調波成分を考慮していない。

…（１０）
上式（１０）に、空間高調波の各項が右辺に加算される形でｄｈｑｈ座標の回路方程式が表される。
【００２６】
例えば、ｎ＝２の空間高調波を含むモータにおいて、θ_ｅｈ＝−６θ_ｅのｄｈｑｈ座標変換を行う場合、ｄｈｑｈ座標の回路方程式は次式（１１）で表される。

【００２７】
ｄｈｑｈ座標系において、高調波電流指令値ｉｄｈ＊＝０，ｉｑｈ＊＝０の高調波電流制御を行った場合について考察する。高調波電流ｉｄｈ，ｉｑｈがともに０に制御されており、ｄ軸，ｑ軸電流が定常状態であるならば、式（１１）の空間高調波に関わる項での電流ｉｄ，ｉｑの微分値は０になる。式（１１）中のｅｄｈ，ｅｑｈの項は磁石の誘起電圧を表しているが、高調波電流制御では高調波電流を抽出して制御するだけであるから、ｄｑ軸で直流量として表される誘起電圧は高調波電流制御へ影響を及ぼさない。よって、ｄ軸，ｑ軸電流が定常状態の場合には、高調波電流を０に制御する電圧値のｄｈ軸成分ｖｄｈｗ，ｑｈ軸成分ｖｑｈｗとすると、式（１１）から次式（１２）が導かれる。

…（１２）
【００２８】
上式（１２）より、モータの電気的角速度ω、ｄ軸電流ｉｄ、ｑ軸電流ｉｑとｖｄｈｗ，ｖｑｈｗが得られれば、インダクタンスの空間高調波を表すＬ２を次式（１３），（１４）から求めることができる。

…（１３）

…（１４）
【００２９】
ここで、高調波電流ｉｄｈ，ｉｑｈを０に制御する電圧ｖｄｈｗ，ｖｑｈｗが、ｄｈｑｈ座標系での高調波電圧指令値ｖｄｈ^＊，ｖｑｈ^＊と等しい場合には、モータＭの電気的角速度ω、ｄ軸電流ｉｄ、ｑ軸電流ｉｑ　、高調波電圧指令値ｖｄｈ^＊，ｖｑｈ^＊を用いて、インダクタンスの空間高調波を求めることができる。すなわち、空間高調波演算器１０は、３相／ｄｑ変換部９で変換されたｄ軸電流ｉｄおよびｑ軸電流ｉｑと、ＰＩ−ｄｈｑｈ電流制御器８で算出された高調波電圧指令値ｖｄｈ^＊，ｖｑｈ^＊と、モータＭの電気的角速度ωとを用いて、モータＭのインダクタンスの空間高調波Ｌ２を求めることができる。求めたモータＭのインダクタンスの空間高調波Ｌ２は、記憶装置１１に記憶される。
【００３０】
第１の実施の形態におけるモータ制御装置によれば、モータＭの制御に用いる各種状態量、すなわち、ｄ軸電流ｉｄ、ｑ軸電流ｉｑ、高調波電流ｉｄｈ，ｉｑｈを０に制御する電圧ｖｄｈｗ，ｖｑｈｗ、モータＭの電気的角速度ωを用いて、モータの等価回路方程式から、モータＭのインダクタンスの空間高調波を求めることができる。高調波電流ｉｄｈ，ｉｑｈを０に制御する電圧ｖｄｈｗ，ｖｑｈｗがｄｈｑｈ座標系での制御電圧ｖｄｈ^＊，ｖｑｈ^＊と等しい場合には、容易にインダクタンスの空間高調波Ｌ２を求めることができる。すなわち、基本波電流制御回路１００と高調波電流制御回路２００とを備えるモータ制御装置では、ｄ軸電流ｉｄ、ｑ軸電流ｉｑ、ｄｈｑｈ座標系での制御電圧ｖｄｈ^＊，ｖｑｈ^＊、モータＭの電気的角速度ωは、モータＭの制御を行うために通常求められるものであるから、特別な測定器を用いることなくモータＭのインダクタンスの空間高調波を求めることができる。
【００３１】
また、高調波電流制御回路でのｄｈｑｈ座標を、測定対象であるモータＭのインダクタンスの空間高調波を直流量として表せるように設定するので、等価回路方程式を簡易な形で表すことができ、より簡易にインダクタンスの空間高調波を算出することができる。
【００３２】
−第２の実施の形態−
第２の実施の形態におけるモータ制御装置は、ｖｄｈｗ，ｖｑｈｗが高調波電圧指令値ｖｄｈ^＊，ｖｑｈ^＊と一致しない場合に、ｖｄｈｗ，ｖｑｈｗをそれぞれ求めた後、モータＭのインダクタンスの空間高調波を算出する。高調波電流の周波数が低く、ＰＩ−ｄｑ電流制御器１がｄ軸，ｑ軸に含まれる高調波電流も含めてｄ軸電流およびｑ軸電流を制御できる周波数範囲では、ｖｄｈｗ，ｖｑｈｗは、ｖｄｈ^＊，ｖｑｈ^＊とはそれぞれ一致しない。すなわち、ｄ軸電流の制御電圧ｖｄ^＊およびｑ軸電流の制御電圧ｖｑ^＊にも、高調波電流を制御するための電圧成分が存在するので、この電圧成分を抽出して高調波電圧指令値ｖｄｈ^＊，ｖｑｈ^＊に加算することにより、精度の高いｖｄｈｗ，ｖｑｈｗを求めることができる。
【００３３】
図５は、第２の実施の形態におけるモータ制御装置の構成を示す図である。第２の実施の形態におけるモータ制御装置は、第１の実施の形態におけるモータ制御装置の構成に加えて、ｄ軸電流の制御電圧ｖｄ^＊およびｑ軸電流の制御電圧ｖｑ^＊の高調波成分ｖｄ^＊ａ，ｖｑ^＊ａを抽出するハイパスフィルタ６ａと、ハイパスフィルタ６ａで抽出した高調波成分ｖｄ^＊ａ，ｖｑ^＊ａをｄｑ座標系からｄｈｑｈ座標系に変換するｄｑ／ｄｈｑｈ変換部７ａとを備える。
【００３４】
ｄｑ／ｄｈｑｈ変換部７ａは、次式（１５）により、ハイパスフィルタ６ａにて抽出されたｖｄ^＊ａとｖｑ^＊ａをｄｈｑｈ座標系へ座標変換して、ｖｄｈａとｖｑｈａを求める。

加算器２４は、ｄｈｑｈ座標での高調波電流制御電圧ｖｄｈ＊とｖｄｈａとを加算してｖｄｈｗを算出し、加算器２５は、ｄｈｑｈ座標での高調波電流制御電圧ｖｑｈ＊とｖｑｈａとを加算してｖｑｈｗを算出する。空間高調波演算器１０ａは、加算器２４，２５にて算出されたｖｄｈｗ，ｖｑｈｗと、ｄ軸電流ｉｄ、ｑ軸電流ｉｑ、モータＭの電気的角速度ωを用いて、式（１３），（１４）より、モータＭのインダクタンスの空間高調波を求める。求めたインダクタンスの空間高調波は、記憶装置１１に記憶される。
【００３５】
−モータの磁石磁束に歪みが存在する場合−
モータＭの磁石磁束に歪みが存在し、高調波電流の発生源となっている場合、磁石の誘起電圧ｅｄｈ，ｅｑｈの高調波次数によってはｄｈｑｈ座標において、インダクタンスの空間高調波による速度起電力と同様に直流量で表される。そのため、高調波電流を０に制御する電圧値のｄｈ軸成分ｖｄｈｗおよびｑｈ軸成分ｖｑｈｗは、式（１２）とは異なり、次式（１６）で表される。

【００３６】
このような場合、式（１６）から磁石の誘起電圧ｅｄｈ，ｅｑｈのうち、直流量として表される分も考慮した式（１７），（１８）からインダクタンスの空間高調波を求めることができる。

ここで、磁石の誘起電圧ｅｄｈ，ｅｑｈの大きさは、電力変換部４によりモータＭに電圧を印加せずに、他の駆動手段を用いてモータＭを回転させたときの誘起電圧などから測定することができる。
【００３７】
−第３の実施の形態−
第１の実施の形態および第２の実施の形態におけるモータ制御装置のように、モータＭのインダクタンスの空間高調波Ｌ２を算出することができれば、高調波速度起電力の補償制御が可能になる。ｄｈｑｈ座標系を次数ｋ＝−６で変換される座標に設定すると、インダクタンスの空間高調波ｎ＝２の成分が式（１２）のように速度起電力として表される。この高調波速度起電力は、電流制御系に対しては外乱として作用するので、電流の応答性を悪化させる要因となる。第３の実施の形態におけるモータ制御装置は、ｄｈｑｈ電流制御系において、高調波速度起電力を推定し、推定した高調波速度起電力を高調波制御出力電圧に加算して補償を行うことで、電流応答性を向上させる
【００３８】
図６は、第３の実施の形態におけるモータ制御装置の構成を示す図である。以下では、図１に示す第１の実施の形態におけるモータ制御装置と異なる構成部分を中心に説明する。高調波速度起電力推定器３０は、記憶装置１１ａに記憶されているインダクタンスの空間高調波Ｌ２、ｄ軸電流ｉｄ，ｑ軸電流ｉｑおよびモータＭの電気的角速度ωに基づいて、ｄｈ軸，ｑｈ軸の高調波速度起電力Ｋｄｈｗ，Ｋｑｈｗをそれぞれ推定する。なお、記憶装置１１ａに記憶されているインダクタンスの空間高調波Ｌ２は、上述した第１の実施の形態または第２の実施の形態で算出した方法により求めることができる。高調波速度起電力Ｋｄｈｗ，Ｋｑｈｗは、それぞれ次式（１９），（２０）で表される。

【００３９】
高調波速度起電力推定器３０にて推定された高調波速度起電力Ｋｄｈｗ，Ｋｑｈｗは、加算器２６，２７に出力される。加算器２６は、ｄｈ軸の高調波速度起電力ＫｄｈｗとＰＩ−ｄｈｑｈ電流制御器８の制御出力値とを加算して、高調波電圧指令値ｖｄｈ^＊を算出する。同様に、加算器２７は、ｑｈ軸の高調波速度起電力ＫｑｈｗとＰＩ−ｄｈｑｈ電流制御器８の制御出力値とを加算して、高調波電圧指令値ｖｑｈ^＊を算出する。これにより、高調波速度起電力の補償制御を行うことができる。
【００４０】
図７は、高調波電流制御の応答結果を表す一例であり、横軸は時間、縦軸はｑｈ軸の高調波電流ｉｑｈを示している。図７は、時刻０．１（ｓｅｃ）の時に、高調波電流指令値ｉｑｈ^＊＝０としたときの電流制御応答性を示しているが、高調波速度起電力の補償が無い場合に比べて、高調波速度起電力の補償がある場合の方が応答性が良いことが分かる。
【００４１】
−変形例−
高調波速度起電力推定器３０は、高調波速度起電力Ｋｄｈｗ，Ｋｑｈｗを推定する際に、式（１９），（２０）に示すように、電流センサ２２，２３で検出したモータＭの電流値ｉｄ，ｉｑを用いたが、ｄ軸電流指令値ｉｄ^＊およびｑ軸電流指令値ｉｑ^＊を用いてもよい。この場合のモータ制御装置の構成を図８に示す。高調波速度起電力推定器３０ａは、次式（２１），（２２）を用いて高調波速度起電力Ｋｄｈｗ，Ｋｑｈｗを推定する。

【００４２】
第３の実施の形態におけるモータ制御装置によれば、算出されたモータＭのインダクタンスの空間高調波Ｌ２を用いて、高調波電流制御において外乱として作用する高調波速度起電力を推定し、推定した高調波速度起電力を用いて高調波速度起電力の補償制御を行うので、高調波電流制御の応答性を高め、モータＭの効率・性能を向上させることができる。
【００４３】
なお、以上の式（１１）〜（２２）はインダクタンスの空間高調波ｎ＝２を例にあげて説明をしたが、他のｎについても同様に、回路方程式からインダクタンスの空間高調波の値を求めることができる。
【００４４】
本発明は、上述した実施の形態に限定されることはない。例えば、第３の実施の形態におけるモータ制御装置の変形例では、高調波速度起電力Ｋｄｈｗ，Ｋｑｈｗを推定する際に、電流センサ２２，２３で検出したモータＭの電流値ｉｄ，ｉｑの代わりに、ｄ軸電流指令値ｉｄ^＊およびｑ軸電流指令値ｉｑ^＊を用いた。同様に、第１および第２の実施の形態におけるモータ制御装置において、ｄ軸，ｑ軸電流制御によってｉｄ，ｉｑが電流指令値ｉｄ^＊，ｉｑ^＊に収束している場合には、式（１３），（１４），（１７），（１８）のｉｄ，ｉｑの代わりに、ｉｄ^＊，ｉｑ^＊を用いてインダクタンス空間高調波を測定することもできる（次式（２３）〜（２６））。
・式（１３），（１４）にｉｄ^＊，ｉｑ^＊を用いた場合

・式（１７），（１８）にｉｄ^＊，ｉｑ^＊を用いた場合

この場合、電流センサ２２，２３で検出する電流に含まれる電流リプルやノイズなどの影響を受けることがなくなるので、精度良くインダクタンスの空間高調波を算出することができる。
【００４５】
また、モータ制御を行うモータＭは、上述した同期モータに限定されることはなく、誘導モータにも本発明によるモータ制御装置を適用することができる。
【００４６】
特許請求の範囲の構成要素と一実施の形態の構成要素との対応関係は次の通りである。すなわち、基本波電流制御回路１００が基本波電流制御手段を、高調波電流制御回路２００が高調波電流制御手段を、空間高調波演算器１０が空間高調波演算手段を、ハイパスフィルタ６ａが高調波成分抽出手段を、加算器２４，２５が加算手段を、電流センサ２２，２３が電流検出手段を、３相／ｄｑ変換部５が座標変換手段を、高調波速度起電力推定器３０が高調波速度起電力推定手段を、加算器２６，２７が補償手段をそれぞれ構成する。なお、本発明の特徴的な機能を損なわない限り、各構成要素は上記構成に限定されるものではない。
【図面の簡単な説明】
【図１】第１の実施の形態におけるモータ制御装置の構成を示す図
【図２】高調波電流の３相交流座標系における次数ｍと、ｄｑ軸座標系における次数ｋとの関係を示す表
【図３】理想的なＩＰＭモータの自己インダクタンス
【図４】空間高調波を含むＩＰＭモータの自己インダクタンス
【図５】第２の実施の形態におけるモータ制御装置の構成を示す図
【図６】第３の実施の形態におけるモータ制御装置の構成を示す図
【図７】高調波速度起電力補償が有るときと無いときの高調波電流ｉｑｈの制御応答性結果を示す図
【図８】第３の実施の形態おけるモータ制御装置の変形構成例を示す図
【符号の説明】
１…ＰＩ−ｄｑ電流制御器、２…ｄｑ／３相変換部、３…非干渉制御部、４…電力変換部、５…３相／ｄｑ変換部、６…ハイパスフィルタ、７…ｄｑ／ｄｈｑｈ変換部、８…ＰＩ−ｄｑ電流制御器、９…ｄｈｑｈ／３相変換部、１０…空間高調波演算器、１１，１１ａ…記憶装置、１２…位相速度演算部、１３，１４，２０，２１…減算器、１５，１６，１７，１８，１９，２４，２５，２６，２７…加算器、２２，２３…電流センサ、３０，３０ａ…高調波速度起電力推定器、１００…基本波電流制御回路、２００…高調波電流制御回路、ＰＳ…エンコーダ、３相同期モータ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a three-phase AC motor.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 2000-313498 discloses a means for measuring the inductance of a permanent magnet type synchronous motor from the phase difference between the fundamental wave of voltage and current. Further, the inductance of the synchronous motor is expressed by an equivalent circuit equation of a motor. Means for measuring by use are disclosed.
[0003]
[Problems to be solved by the invention]
However, in the related art, when the inductance of the motor changes spatially, the fundamental component of the inductance can be measured, but the spatial harmonic cannot be measured. Further, when controlling the harmonic current of the motor, there is a problem that the response of the harmonic current is slow due to the influence of the spatial harmonic of the inductance.
[0004]
An object of the present invention is to provide a motor control device that calculates a spatial harmonic of an inductance of a motor.
[0005]
[Means for Solving the Problems]
A motor control device according to the present invention controls a fundamental wave current of a motor in a rectangular coordinate system (hereinafter, referred to as a dq coordinate system) including a d-axis and a q-axis rotating in synchronization with the rotation of a three-phase AC motor. Current control means for controlling a harmonic current of a motor in a rectangular coordinate system (hereinafter referred to as a dhqh coordinate system) comprising a dh axis and a qh axis rotating at an integral multiple of the frequency of a fundamental component of a current flowing through the motor; Current control means for controlling the harmonic current to 0 in the dhqh coordinate system, the current value in the dq coordinate system, and the rotational speed of the motor, based on the harmonic current control means. The above object is achieved by providing spatial harmonic calculating means for calculating harmonics.
[0006]
【The invention's effect】
According to the motor control device of the present invention, the motor control device includes a fundamental current control unit, a harmonic current control unit, and a spatial harmonic calculation unit, and the spatial harmonic calculation unit controls the harmonic current to 0 in the dhqh coordinate system. To calculate the spatial harmonics of the inductance of the motor based on the harmonic control voltage, the current value in the dq coordinate system, and the rotation speed of the motor for controlling the motor without providing any special measuring means. Spatial harmonics of the inductance can be calculated based on the state quantities for the calculation.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
-1st Embodiment-
FIG. 1 is a control block diagram illustrating a configuration of the motor control device according to the first embodiment. The motor control device according to the first embodiment includes a fundamental current control circuit 100 and a harmonic current control circuit 200. The fundamental wave current control circuit 100 is a rectangular coordinate system including a d-axis corresponding to the exciting current component of the currents iu, iv, and iw flowing through the three-phase synchronous motor M and a q-axis corresponding to the torque current component, that is, the motor rotation. Is a circuit for controlling the fundamental wave components of the motor currents iu, iv, iw in a dq coordinate system that rotates in synchronization with.
[0008]
The harmonic current control circuit 200 is a rectangular coordinate system (hereinafter, harmonic coordinate system) that rotates at a frequency of a harmonic component of a predetermined order generated when the motor currents iu, iv, and iw are controlled only by the fundamental current control circuit 100. This is a circuit for controlling harmonic components included in the motor currents iu, iv, iw. In other words, the harmonic coordinate system is a coordinate system that rotates at a frequency that is an integral multiple of the frequency of the fundamental component of the motor currents iu, iv, and iw.
[0009]
The fundamental wave current control circuit 100 includes a PI-dq current controller 1, a dq / 3-phase converter 2, a non-interference controller 3, a power converter 4, a three-phase / dq converter 5, a phase speed calculator 12, a subtraction It has units 13 and 14 and adders 15 and 16. The subtractors 13 and 14 calculate deviations (id ^* -id) and (iq ^* -iq) between the actual currents id and iq on the d-axis and q-axis and the current command values id ^* and iq ^* . The PI-dq current controller 1 calculates PI (proportional / integral) of the fundamental wave current deviations (id ^* -id) and (iq ^* -iq) calculated by the subtractors 13 and 14, thereby obtaining a dq-axis voltage. Calculate the command value.
[0010]
The non-interference control unit 3 includes a d-axis compensation voltage Vd_cmp for compensating for the speed electromotive force in the dq-axis coordinate system and compensating for the speed electromotive force in the dq-axis coordinate system to improve the response of the dq-axis current. A q-axis compensation voltage Vq_cmp is calculated. The adders 15 and 16 add the control output of the PI-dq current controller 1, the d-axis compensation voltage Vd_cmp and the q-axis compensation voltage Vq_cmp calculated by the non-interference controller 3, respectively, and Calculate the fundamental wave voltage command values vd ^* and vq ^* of the axis. The dq / 3-phase converter 2 converts the d-axis and q-axis voltage command values vd ^* , vq ^* into three-phase AC voltage command values vu ^* , vv based on the phase θe of the fundamental wave current of the three-phase AC motor M. ^* , Vw ^* .
[0011]
The adders 17, 18, and 19 convert the three-phase AC voltage command values vu ^* , vv ^* , and vw ^* converted by the dq / 3-phase converter 2 into three-phase AC voltage values converted by the dhqh / 3-phase converter 9 described later. The phase AC voltage command values vu ', vv', and vw 'are respectively added, and the addition result is output to the power conversion unit 4. The power conversion unit 4 switches the DC voltage of a DC power supply (not shown) such as a battery by a power conversion element such as an IGBT according to the voltage command value added by the adders 17, 18, and 19, and outputs a three-phase AC voltage. U, V, and W are applied to the three-phase AC motor M.
[0012]
The encoder PS is connected to the three-phase AC motor M and detects the rotational position θm of the motor M. The phase speed calculator 12 calculates the phase θe of the fundamental wave current based on the rotational position signal θm from the encoder PS, and calculates the phase for performing dq / dhqh coordinate conversion based on the phase θe of the fundamental wave current. Calculate θeh. The phase θeh is obtained by the following equation (1), where k is the order of harmonics on the dq axes.

[0013]
FIG. 2 is a table showing the relationship between the order m of harmonic current in three-phase AC coordinates and the order k in dq-axis coordinates. For example, when the fifth harmonic current is converted into a dq coordinate system in three-phase AC coordinates, k = −6 (= −5-1) becomes −6th harmonic current.
[0014]
The current sensors 22 and 23 detect the U-phase and V-phase actual currents iu and iv of the three-phase AC motor M. The three-phase / dq conversion unit 5 converts the real currents iu, iv, iw (= −iu-iv) of the three-phase AC motor M based on the fundamental current phase θe into real currents id, iq on the d-axis and the q-axis. Convert to
[0015]
The harmonic current control circuit includes a high-pass filter 6, a dq / dhqh converter 7, a PI-dhqh current controller 8, a dhqh / 3-phase converter 9, a spatial harmonic calculator 10, a storage device 11, and an adder 20, 21. The high-pass filter 6 filters the actual currents id and iq on the d-axis and the q-axis to extract high-frequency components. The dq / dhqh conversion unit 7 is a rectangular coordinate system (a harmonic coordinate system) that rotates at a frequency of a harmonic component of a predetermined order generated when the motor currents iu, iv, and iw are controlled only by the above-described fundamental wave current control circuit. ) Has dhqh, and converts the high-frequency components of the real currents id and iq of the d-axis and the q-axis to the real currents idh and iqh of the harmonic coordinate system dhqh, respectively.
[0016]
The subtractors 20 and 21 calculate the difference between the actual currents idh and iqh on the dh axis and the qh axis and the current command values idh ^* and iqh ^* . The PI-dhqh current controller 8 calculates the dh-axis and qh-axis harmonic voltage command values vdh ^* and vqh ^* based on the result obtained by the subtracters 20 and 21. The dhdq / 3-phase converter 9 converts the dh-axis harmonic voltage command value vdh ^* and the qh-axis harmonic voltage command value vqh ^* into three-phase AC voltage command values vd 'and vq', respectively. The three-phase AC voltage command values vd 'and vq' converted by the dhdq / 3-phase converter 9 are output to adders 17, 18, and 19, respectively.
[0017]
The spatial harmonic calculator 10 calculates the d-axis and q-axis actual currents id and iq, the electric angular velocity ω of the motor M, and the harmonic voltage command values vdh ^* and vqh ^* calculated by the PI-dq current controller 8. Based on this, a spatial harmonic L2 of the inductance of the motor M is calculated. The method of calculating the spatial harmonic L2 of the inductance will be described later. The calculated spatial harmonic L2 of the inductance is stored in the storage device 11.
[0018]
As factors for the generation of harmonic current of the synchronous motor, spatial harmonics of inductance and harmonics of magnet magnetic flux can be considered. In the case of an embedded permanent magnet (IPM) motor, ideally, the self-inductance in three phases varies sinusoidally with respect to the phase, as shown in FIG. Depending on the shape of the rotor of the IPM motor, as shown in FIG. 3, the inductance changes as a sine wave having a distortion with respect to the phase, and such distortion (spatial harmonic) causes a harmonic current to occur. . In the following, coordinate conversion is performed on spatial harmonics of inductance to derive circuit equations in a dq coordinate system and a dhqh coordinate system.
[0019]
The self-inductances Lu, Lv, and Lw in the three-phase alternating current can be expressed by the following equation (2) when spatial harmonics are taken into consideration.

… (2)
[0020]
In the above equation (1), Lo is a DC component of the inductance of the three-phase synchronous motor M, Ln (n = 1, 2,...) Is an AC component of the inductance of the motor M, and θe is an electrical angle of the motor M. In the equation (1), when n = 1, the second term on the right side is a term representing the saliency of an IPM motor having a general internal magnet structure, and the self-inductance Lu of each phase when n ≧ 2. , Lv, and Lw are the causes of the generation of the harmonic speed electromotive force.
[0021]
In a typical IPM motors, d-axis inductance Ld and q-axis inductance Lq, using _{L 0} and _{L 1,} the following equations (3), represented by (4).

[0022]
A dq coordinate circuit equation of a general IPM motor expressed by using d-axis and q-axis inductances is expressed by the following equation (5). Here, R represents the armature resistance of the motor M, ω represents the electrical angular velocity of the motor M, and p represents the differential operator. Φ is an induced voltage constant due to the magnet magnetic flux.

[0023]
Regarding the component of n ≧ 2 representing the spatial harmonic of the inductance, the terms of the following equations (6) and (7) are added to the right side of the equation (5) depending on the case of n.
・ When n = 1,4,7 ...

… (6)
・ When n = 2,5,8 ...

… (7)
[0024]
The spatial harmonic of the inductance acts as a harmonic velocity electromotive force, and when this is converted into the dhqh coordinates, the order of the harmonic is calculated using the spatial harmonic order n of the inductance to obtain the phase θeh. Harmonics can be represented as simple DC quantities. The spatial harmonics are represented as the sum of the respective orders n, but here, one of them is taken out and represented.
When n = 1, 4, 7,... When the equation (6) is converted using the phase θ _eh = (2n−2) θ _e in the conversion of the dhqh coordinate conversion,

It becomes.
When n = 2, 5, 8,... When the equation (7) is converted using the phase θ _eh = − (2n + 2) θ _e in the conversion of the dhqh coordinate conversion,

It becomes.
[0025]
When the circuit equation in the dq coordinate system is represented as a circuit equation in the dhqh coordinate system, the following equation (10) is obtained. However, the circuit equation represented by Expression (10) does not consider the spatial harmonic component.

… (10)
In the above equation (10), a circuit equation of dhqh coordinates is expressed in a form in which each term of the spatial harmonic is added to the right side.
[0026]
For example, in a motor including n = 2 spatial harmonics, when performing dhqh coordinate conversion of θ _eh = −6θ _e , a circuit equation of dhqh coordinates is represented by the following equation (11).

[0027]
Consider the case where harmonic current control is performed with the harmonic current command values idh * = 0 and iqh * = 0 in the dhqh coordinate system. If the harmonic currents idh and iqh are both controlled to be 0 and the d-axis and q-axis currents are in a steady state, the differential value of the currents id and iq in the term relating to the spatial harmonics in equation (11) is It becomes 0. The terms of edh and eqh in the equation (11) represent the induced voltage of the magnet. However, in the harmonic current control, only the harmonic current is extracted and controlled. The induced voltage has no effect on harmonic current control. Therefore, when the d-axis and q-axis currents are in a steady state, assuming that dh-axis components vdhw and qh-axis components vqhw of the voltage values for controlling the harmonic current to 0, the following equation (12) is obtained from the equation (11). Be guided.

… (12)
[0028]
If the electric angular velocity ω, d-axis current id, q-axis current iq and vdhw, vqhw of the motor can be obtained from the above equation (12), L2 representing the spatial harmonic of the inductance can be expressed by the following equations (13), (14). Can be obtained from

… (13)

… (14)
[0029]
Here, when the voltages vdhw, vqhw for controlling the harmonic currents idh, iqh to 0 are equal to the harmonic voltage command values vdh ^* , vqh ^* in the dhqh coordinate system, the electric angular velocity ω, d of the motor M is obtained. Using the axis current id, the q-axis current iq, and the harmonic voltage command values vdh ^* , vqh ^* , a spatial harmonic of the inductance can be obtained. That is, the spatial harmonic calculator 10 includes the d-axis current id and the q-axis current iq converted by the three-phase / dq converter 9 and the harmonic voltage command value vdh ^* calculated by the PI-dhqh current controller 8 ^. , Vqh ^* and the electric angular velocity ω of the motor M, the spatial harmonic L2 of the inductance of the motor M can be obtained. The obtained spatial harmonic L2 of the inductance of the motor M is stored in the storage device 11.
[0030]
According to the motor control device in the first embodiment, various state quantities used for controlling the motor M, that is, the voltage vdhw, which controls the d-axis current id, the q-axis current iq, and the harmonic currents idh, iqh to 0, Using vqhw and the electric angular velocity ω of the motor M, a spatial harmonic of the inductance of the motor M can be obtained from the equivalent circuit equation of the motor. When the voltages vdhw, vqhw for controlling the harmonic currents idh, iqh to 0 are equal to the control voltages vdh ^* , vqh ^* in the dhqh coordinate system, the spatial harmonic L2 of the inductance can be easily obtained. That is, in the motor control device including the fundamental wave current control circuit 100 and the harmonic current control circuit 200, the d-axis current id, the q-axis current iq, the control voltages vdh ^* and vqh ^* in the dhqh coordinate system, and the electric power of the motor M Since the target angular velocity ω is normally obtained for controlling the motor M, a spatial harmonic of the inductance of the motor M can be obtained without using a special measuring device.
[0031]
Further, since the dhqh coordinates in the harmonic current control circuit are set so that the spatial harmonic of the inductance of the motor M to be measured can be expressed as a DC amount, the equivalent circuit equation can be expressed in a simple form. Spatial harmonics of the inductance can be easily calculated.
[0032]
-2nd Embodiment-
When vdhw and vqhw do not match the harmonic voltage command values vdh ^* and vqh ^* , the motor control device according to the second embodiment determines vdhw and vqhw, respectively, and then calculates the spatial harmonic of the inductance of the motor M. calculate. In a frequency range where the frequency of the harmonic current is low and the PI-dq current controller 1 can control the d-axis current and the q-axis current including the harmonic current included in the d-axis and the q-axis, vdhw and vqhw are vdh ^* And vqh ^* do not coincide with each other. That is, since the control voltage vd ^* of the d-axis current and the control voltage vq ^* of the q-axis current also have a voltage component for controlling the harmonic current, the voltage component is extracted and the harmonic voltage command value vdh is extracted. By adding to ^* , vqh ^* , highly accurate vdhw, vqhw can be obtained.
[0033]
FIG. 5 is a diagram illustrating a configuration of a motor control device according to the second embodiment. The motor control device according to the second embodiment includes, in addition to the configuration of the motor control device according to the first embodiment, a harmonic component vd of the control voltage vd ^* of the d-axis current and the control voltage vq ^* of the q-axis current. comprising ^* a, and the high-pass filter 6a for extracting vq ^* a, harmonic component ^vd * a extracted by the high-pass filter 6a, and a dq / dhqh conversion unit 7a for converting vq ^* a from the dq coordinate system in dhqh coordinate system .
[0034]
The dq / dhqh conversion unit 7a converts the vd ^* a and vq ^* a extracted by the high-pass filter 6a into a dhqh coordinate system by the following equation (15), and obtains vdha and vqha.

The adder 24 adds the harmonic current control voltages vdh * and vdha on the dhqh coordinates to calculate vdhw, and the adder 25 adds the harmonic current control voltages vqh * and vqha on the dhqh coordinates. To calculate vqhw. The spatial harmonic calculator 10a uses the vdhw and vqhw calculated by the adders 24 and 25, the d-axis current id, the q-axis current iq, and the electric angular velocity ω of the motor M to obtain the equations (13) and (13). 14), the spatial harmonic of the inductance of the motor M is obtained. The obtained spatial harmonic of the inductance is stored in the storage device 11.
[0035]
-When there is distortion in the magnetic flux of the motor-
When distortion is present in the magnet magnetic flux of the motor M and is a source of a harmonic current, depending on the harmonic order of the induced voltages edh and eqh of the magnet, the velocity electromotive force due to the spatial harmonic of the inductance and the dhqh coordinate may be used. Similarly, it is represented by a DC amount. Therefore, the dh-axis component vdhw and the qh-axis component vqhw of the voltage value for controlling the harmonic current to 0 are different from the equation (12) and expressed by the following equation (16).

[0036]
In such a case, the spatial harmonics of the inductance can be obtained from Expressions (17) and (18), which also take into account the amount expressed as a DC amount among the induced voltages edh and eqh of the magnet from Expression (16).

Here, the magnitudes of the induced voltages edh and eqh of the magnet are measured from the induced voltage when the motor M is rotated by using other driving means without applying a voltage to the motor M by the power converter 4. can do.
[0037]
-Third embodiment-
If the spatial harmonic L2 of the inductance of the motor M can be calculated as in the motor control devices according to the first and second embodiments, the compensation control of the harmonic speed electromotive force becomes possible. When the dhqh coordinate system is set to coordinates converted by the order k = −6, the component of the spatial harmonic n = 2 of the inductance is expressed as a speed electromotive force as in Expression (12). Since this harmonic velocity electromotive force acts as a disturbance on the current control system, it becomes a factor of deteriorating the current responsiveness. The motor control device according to the third embodiment estimates the harmonic velocity electromotive force in the dhqh current control system, and performs compensation by adding the estimated harmonic velocity electromotive force to the harmonic control output voltage. Improve current responsiveness
FIG. 6 is a diagram illustrating a configuration of a motor control device according to the third embodiment. In the following, a description will be given mainly of components different from those of the motor control device according to the first embodiment shown in FIG. The harmonic velocity electromotive force estimator 30 calculates the dh axis, qh, and dh axes based on the spatial harmonic L2 of the inductance, the d-axis current id, the q-axis current iq, and the electric angular velocity ω of the motor M stored in the storage device 11a. The harmonic velocity electromotive forces Kdhw and Kqhw of the shaft are respectively estimated. Note that the spatial harmonic L2 of the inductance stored in the storage device 11a can be obtained by the method calculated in the above-described first or second embodiment. The harmonic velocity electromotive forces Kdhw and Kqhw are expressed by the following equations (19) and (20), respectively.

[0039]
The harmonic velocity electromotive forces Kdhw and Kqhw estimated by the harmonic velocity electromotive force estimator 30 are output to the adders 26 and 27. The adder 26 adds the dh-axis harmonic velocity electromotive force Kdhw and the control output value of the PI-dhqh current controller 8 to calculate a harmonic voltage command value vdh ^* . Similarly, the adder 27 adds the qh-axis harmonic velocity electromotive force Kqhw and the control output value of the PI-dhqh current controller 8 to calculate a harmonic voltage command value vqh ^* . Thereby, it is possible to perform the compensation control of the harmonic speed electromotive force.
[0040]
FIG. 7 is an example showing the response result of the harmonic current control, in which the horizontal axis represents time and the vertical axis represents the harmonic current iqh on the qh axis. FIG. 7 shows the current control responsiveness when the harmonic current command value iqh ^* = 0 at time 0.1 (sec). Compared to the case where there is no compensation of the harmonic speed electromotive force, It can be seen that the response is better when the harmonic velocity electromotive force is compensated.
[0041]
-Modification-
When estimating the harmonic velocity electromotive forces Kdhw and Kqhw, the harmonic velocity electromotive force estimator 30 calculates the current value of the motor M detected by the current sensors 22 and 23 as shown in Expressions (19) and (20). Although id and iq are used, a specified d-axis current value id ^* and a specified q-axis current value iq ^* may be used. FIG. 8 shows the configuration of the motor control device in this case. The harmonic velocity electromotive force estimator 30a estimates the harmonic velocity electromotive forces Kdhw and Kqhw using the following equations (21) and (22).

[0042]
According to the motor control device in the third embodiment, the harmonic velocity electromotive force acting as a disturbance in the harmonic current control is estimated and estimated using the calculated spatial harmonic L2 of the inductance of the motor M. Since the compensation control of the harmonic speed electromotive force is performed using the harmonic speed electromotive force, the responsiveness of the harmonic current control can be improved, and the efficiency and performance of the motor M can be improved.
[0043]
In the above equations (11) to (22), the spatial harmonics of the inductance n = 2 have been described as an example, but the values of the spatial harmonics of the inductance are similarly calculated from the circuit equations for the other n. You can ask.
[0044]
The present invention is not limited to the embodiments described above. For example, in a modified example of the motor control device according to the third embodiment, when estimating the harmonic speed electromotive forces Kdhw and Kqhw, instead of the current values id and iq of the motor M detected by the current sensors 22 and 23, respectively. , D-axis current command value id ^* and q-axis current command value iq ^* . Similarly, in the motor control devices according to the first and second embodiments, when id and iq converge to current command values id ^* and iq ^* by d-axis and q-axis current control, the equation (13) is used. ), (14), (17) and (18) can be used to measure the inductance spatial harmonics using id ^* and iq ^* instead of id and iq (the following equations (23) to (26)). .
・ When id ^* and iq ^* are used in equations (13) and (14)

・ When id ^* and iq ^* are used in equations (17) and (18)

In this case, since there is no influence of current ripple and noise included in the current detected by the current sensors 22 and 23, the spatial harmonic of the inductance can be calculated with high accuracy.
[0045]
Further, the motor M that performs the motor control is not limited to the synchronous motor described above, and the motor control device according to the present invention can be applied to an induction motor.
[0046]
The correspondence between the components of the claims and the components of the embodiment is as follows. That is, the fundamental current control circuit 100 is a fundamental current control means, the harmonic current control circuit 200 is a harmonic current control means, the spatial harmonic operation unit 10 is a spatial harmonic operation means, and the high-pass filter 6a is a harmonic current control means. The component extracting means, the adders 24 and 25 are the adding means, the current sensors 22 and 23 are the current detecting means, the three-phase / dq converter 5 is the coordinate converting means, and the harmonic velocity electromotive force estimator 30 is the harmonic. The speed electromotive force estimating means and the adders 26 and 27 constitute compensating means, respectively. Note that each component is not limited to the above configuration as long as the characteristic functions of the present invention are not impaired.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a motor control device according to a first embodiment. FIG. 2 is a table illustrating a relationship between an order m of a harmonic current in a three-phase AC coordinate system and an order k in a dq-axis coordinate system. FIG. 3 is an ideal self-inductance of an IPM motor; FIG. 4 is a self-inductance of an IPM motor including spatial harmonics; FIG. 5 is a diagram showing a configuration of a motor control device according to a second embodiment; FIG. 7 is a diagram illustrating a configuration of a motor control device according to a third embodiment. FIG. 7 is a diagram illustrating a control responsiveness result of a harmonic current iqh with and without harmonic velocity electromotive force compensation. The figure which shows the example of a modified structure of the motor control apparatus in embodiment.
DESCRIPTION OF SYMBOLS 1 ... PI-dq current controller, 2 ... dq / 3 phase conversion part, 3 ... non-interference control part, 4 ... power conversion part, 5 ... three phase / dq conversion part, 6 ... High pass filter, 7 ... dq / dhqh Conversion unit, 8: PI-dq current controller, 9: dhqh / 3-phase conversion unit, 10: spatial harmonic operation unit, 11, 11a: storage device, 12: phase velocity operation unit, 13, 14, 20, 21 ... Subtractor, 15, 16, 17, 18, 19, 24, 25, 26, 27 ... Adder, 22, 23 ... Current sensor, 30, 30a ... Harmonic velocity electromotive force estimator, 100 ... Fundamental wave current control Circuit, 200: harmonic current control circuit, PS: encoder, three-phase synchronous motor

Claims (7)

Fundamental wave current control means for controlling a fundamental wave current of the motor in a rectangular coordinate system (hereinafter referred to as a dq coordinate system) composed of a d-axis and a q-axis rotating in synchronization with the rotation of the three-phase AC motor;
A harmonic for controlling a harmonic current of the motor in a rectangular coordinate system (hereinafter, referred to as a dhqh coordinate system) including a dh axis and a qh axis rotating at a frequency that is an integral multiple of the frequency of the fundamental component of the current flowing through the motor. Current control means;
A spatial harmonic of the inductance of the motor is calculated based on a harmonic control voltage for controlling a harmonic current to 0 in the dhqh coordinate system, a current value in the dq coordinate system, and a rotation speed of the motor. A motor control device, comprising: The motor control device according to claim 1,
In the dhqh coordinate system, a spatial harmonic of an inductance of the motor is represented as a DC amount. The motor control device according to claim 1 or 2,
The motor control device, wherein the harmonic control voltage is a control voltage for matching a harmonic current in the dhqh coordinate system with a harmonic current command value. The motor control device according to claim 3,
Harmonic component extraction means for extracting a harmonic component included in the current control voltage in the dq coordinate system;
An adder that adds a harmonic component included in the current control voltage in the dq coordinate system and a control voltage in the dhqh coordinate system,
The motor control device, wherein the spatial harmonic calculating means calculates a spatial harmonic of the inductance of the motor by using an addition result by the adding means as the harmonic control voltage. The motor control device according to any one of claims 1 to 4,
A motor control device, wherein the current value in the dq coordinate system used when the space harmonic calculation means calculates the space harmonic of the inductance of the motor is a current command value in the dq coordinate system. The motor control device according to any one of claims 1 to 4,
Current detection means for detecting a three-phase alternating current flowing through the motor;
Coordinate conversion means for converting the three-phase alternating current detected by the current detection means into a current value in the dq coordinate system,
A motor control device, wherein the current value in the dq coordinate system used when the space harmonic calculation means calculates the space harmonic of the inductance of the motor is a current value subjected to coordinate conversion by the coordinate conversion means. . The motor control device according to any one of claims 1 to 6,
A harmonic velocity electromotive force estimation means for estimating a harmonic velocity electromotive force of the motor using a spatial harmonic of the inductance calculated by the spatial harmonic calculation means,
A motor control device, further comprising: a compensator for compensating for the harmonic velocity electromotive force estimated by the harmonic velocity electromotive force estimator.

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