JP2004007900A

JP2004007900A - Controller for synchronous motor

Info

Publication number: JP2004007900A
Application number: JP2002159405A
Authority: JP
Inventors: Hisafumi Nomura; 野村　尚史; Hiroshi Osawa; 大沢　博; Fukashi Uehara; 上原　深志
Original assignee: Fuji Electric Holdings Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 2002-05-31
Filing date: 2002-05-31
Publication date: 2004-01-08
Anticipated expiration: 2022-05-31
Also published as: JP3824159B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a synchronous motor which accomplishes torque control over a wide speed range from low-speed operation to high-speed operation, enhances efficiency and reduces equipment capacitance. <P>SOLUTION: The controller for synchronous motor comprises a first torque controlling means which controls the terminal voltage of a synchronous motor so that a detected current value matches a commanded current value which gives desired torque; and a second torque controlling means which controls the phase of the terminal voltage so that a computed torque value computed from a detected current value and a motor constant matches with a commanded torque value. The controller switches between the first torque controlling means and the second torque controlling means according to a control switching signal from a control changer 11 corresponding to the state of the operation of a motor 300 (commanded value of voltage amplitude V<SP>*</SP>). Further, the controller is provided with a function of suppressing shock in control change as required. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、電力変換器によって永久磁石形同期電動機をはじめとする同期電動機を駆動するための制御装置に関し、詳しくは、トルク制御手段に特徴を有する制御装置に関するものである。
【０００２】
【従来の技術】
図６は、従来の永久磁石形同期電動機の制御ブロック図を示している。
図において、電流指令演算器１０１は、トルク指令値τ^＊及び速度検出値ωに基づいて、同期電動機３００の端子電圧が電力変換器２００の最大出力電圧を越えない条件で所望のトルクが得られる直軸電流指令値ｉ_ｄ ^＊及び横軸電流指令値ｉ_ｑ ^＊を演算する。この電流指令演算器１０１の構成及び動作は、例えば、平成１３年電気学会産業応用部門全国大会ｐ．１２５７に掲載されているものとする。
なお、速度検出値ωは、同期電動機３００の回転子に取り付けられたパルスジェネレータ１０６の出力パルスから、速度検出回路１０７により検出される。
【０００３】
直軸電流調節器１０２ｄは、直軸電流指令値ｉ_ｄ ^＊と直軸電流検出値ｉ_ｄとの偏差を増幅して直軸電圧指令値ｖ_ｄ ^＊を演算し、横軸電流調節器１０２ｑは、横軸電流指令値ｉ_ｑ ^＊と横軸電流検出値ｉ_ｑとの偏差を増幅して横軸電圧指令値ｖ_ｑ ^＊を演算する。直軸電流検出値ｉ_ｄ及び横軸電流検出値ｉ_ｑは、座標変換器１０９により、同期電動機３００のＵ相電流検出値ｉ_ｕ、Ｗ相電流検出値ｉ_ｗ及び磁極位置検出値θから演算する。なお、磁極位置検出値θは、パルスジェネレータ１０６の出力パルスから磁極位置検出回路１０８により検出される。
【０００４】
極座標変換器１０３は、直軸電圧指令値ｖ_ｄ ^＊及び横軸電圧指令値ｖ_ｑ ^＊から電圧振幅指令値Ｖ^＊及び電圧位相指令φ_０を演算し、座標変換器１０４は、電圧振幅指令値Ｖ^＊、電圧位相指令φ_０及び磁極位置検出値θから三相電圧指令値ｖ_ｕ ^＊，ｖ_ｖ ^＊，ｖ_ｗ ^＊を演算する。これらの三相電圧指令値ｖ_ｕ ^＊，ｖ_ｖ ^＊，ｖ_ｗ ^＊をＰＷＭ回路１０５によりパルス幅変調して電力変換器２００のゲート信号を生成し、このゲート信号を用いて電力変換器２００のスイッチング素子を駆動することにより、同期電動機３００の端子電圧を制御し、同期電動機３００の電流を指令値に制御することによってそのトルクを指令値に制御している。
この制御方法は、同期電動機３００の速度零を含む低速時にも正確なトルク制御が可能であるという特徴を持つ。
【０００５】
【発明が解決しようとする課題】
同期電動機を高効率運転したり、同期電動機と電力変換器とを含めた機器容量を低減するためには、電動機端子電圧を電力変換器の最大出力電圧まで制御できることが望ましい。
しかしながら、図６に示した従来の制御方法では、電流検出値をフィードバックして端子電圧を制御する構成としているため、電動機端子電圧を電力変換器の最大出力電圧に制御しようとすると電圧を指令値どおりに制御できなくなり、電流調節器１０２ｄ，１０２ｑが電流制御系を安定化するように電圧指令値ｖ_ｄ ^＊，ｖ_ｑ ^＊を出力したとしても実際の電動機端子電圧が指令値どおりにならず、制御系の安定性が低下するという問題がある。
【０００６】
また、同期電動機の速度に相当する固有周波数は電力変換器の出力周波数に等しく、一方、電流制御系の応答は電流のサンプリング周波数に比例する。
ディジタル制御装置を用いる場合、同期電動機の速度が高くなるほど電力変換器の出力周波数とサンプリング周波数との比が小さくなるので、同期電動機の固有周波数成分の振動を電流調節器の動作によって低減できなくなり、その結果、電流制御系の安定性が低下するため、この安定性を維持するには同期電動機の最高速度を制限せざるを得ないという問題もある。
【０００７】
上記の課題を解決する手段として、特開平１０−１４２７３号公報に記載された車両駆動用永久磁石同期電動機の制御装置が知られている。
この制御装置では、その図１に示されるように、電圧指令値を電流指令値と速度検出値及び電動機定数から演算し、電圧指令値、電流検出値及び電動機定数から演算したトルク演算値がトルク指令値に一致するようにトルク角補正値を算出し、この補正値により電圧指令値の位相を制御することでトルク制御を実現している。
【０００８】
この制御装置によれば、電圧の位相を制御してトルク制御を行うことができるので、電動機端子電圧を電力変換器の最大出力電圧に制御するときにもトルク制御が容易であり、電流制御系の安定性低下や最高速度の制約といった問題も生じない。
しかしながら、特開平１０−１４２７３号公報記載の制御装置による電圧位相の制御によるトルク制御は、電機子抵抗による電圧降下が電動機端子電圧に比べて十分小さい場合に実現可能な方法であり、電動機端子電圧が低い低速運転時には、電機子抵抗による電圧降下が無視できなくなるので、トルク制御が困難になるという別の課題がある。
【０００９】
そこで本発明は、低速運転時から高速運転時までの広い速度範囲でトルク制御を実現可能とした同期電動機の制御装置を提供しようとするものである。
【００１０】
【課題を解決するための手段】
上記課題を解決するため、本発明では、所望のトルクが得られる電流指令値に電流検出値が一致するように同期電動機の端子電圧を制御する第１のトルク制御手段と、電流検出値と電動機定数とから演算したトルク演算値がトルク指令値に一致するように端子電圧の位相を制御する第２のトルク制御手段とを備え、運転状態に応じて第１のトルク制御手段と第２のトルク制御手段とを切り換えるようにした。
【００１１】
第１のトルク制御手段によるトルク制御は、先に従来技術として述べたように、低速運転時にも正確なトルク制御が可能である反面、高速運転が苦手であるという短所がある。一方、第２のトルク制御手段によるトルク制御は、電動機端子電圧を電力変換器の最大出力電圧に制御するときにもトルク制御が容易であることから、高速運転時の効率向上や機器容量低減に有利であるが、電動機端子電圧が低い低速運転時は制御が困難である短所を持つ。
そこで本発明は、２つのトルク制御方法を組み合わせることにより、広い速度範囲でトルク制御を実現し、これと同時に、効率向上及び機器容量の低減を実現可能とした。
【００１２】
すなわち、請求項１記載の発明は、同期電動機に対するトルク指令値から電流指令値を生成し、この電流指令値から生成した電圧指令値に基づき電力変換器を運転して同期電動機を制御する同期電動機の制御装置において、
前記電流指令値を演算する電流指令演算手段と、
前記電流指令値、同期電動機の速度検出値及び電動機定数から第１の電圧指令値を演算する電圧指令演算手段と、
前記電流指令値に電流検出値が一致するように第１の電圧指令値に基づいて同期電動機の端子電圧を制御する第１のトルク制御手段と、
同期電動機のトルク演算値が前記トルク指令値に一致するように前記端子電圧の位相を制御する第２のトルク制御手段と、
同期電動機の運転状態に応じて第１または第２のトルク制御手段を切り換えて動作させる制御切換手段と、
を備え、
第１のトルク制御手段は、
前記電流指令値と前記電流検出値との偏差を増幅して電圧補正値を演算する電流調節手段と、第１の電圧指令値に前記電圧補正値を加算して第２の電圧指令値を演算する手段と、
第２の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有し、
第２のトルク制御手段は、
前記電流検出値及び電動機定数からトルクを演算するトルク演算手段と、
前記トルク指令値と前記トルク演算値との偏差を増幅して電圧位相補正値を演算する電圧位相調節手段と、
第１の電圧指令値の位相に前記電圧位相補正値を加算して第３の電圧指令値を演算する手段と、
第３の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有するものである。
【００１３】
請求項２に記載した発明は、第１のトルク制御手段が、
前記電流指令値と前記電流検出値との偏差を増幅して電圧補正値を演算する電流調節手段と、第１の電圧指令値に前記電圧補正値を加算して第２の電圧指令値を演算する手段と、
第２の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有し、
第２のトルク制御手段が、
前記電流検出値及び電動機定数からトルクを演算するトルク演算手段と、
前記トルク指令値と前記トルク演算値との偏差を増幅して電圧位相補正値を演算する電圧位相調節手段と、
第１の電圧指令値に前記電圧補正値（第１のトルク制御手段の動作時における電圧補正値であって、後述するメモリに記憶された値）を加算して第２の電圧指令値を演算する手段と、
第２の電圧指令値の位相に前記電圧位相補正値を加算して第３の電圧指令値を演算する手段と、
第３の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有し、
前記制御切換手段が、
第２のトルク制御手段の動作開始時に第１のトルク制御手段の動作時における前記電圧補正値をメモリに記憶する機能と、第２のトルク制御手段の動作時における前記電圧補正値を前記メモリに記憶された値に制御する機能と、第１のトルク制御手段の動作を開始する前に、前記電流調節手段の出力を前記メモリに記憶された値にプリセットする機能と、を有するを有するものである。
【００１４】
請求項３に記載した発明は、第１のトルク制御手段が、
前記電流指令値と前記電流検出値との偏差を増幅して電圧補正値を演算する電流調節手段と、第１の電圧指令値に前記電圧補正値を加算して第２の電圧指令値を演算する手段と、
第２の電圧指令値の位相に電圧位相補正値（第２のトルク制御手段の動作時における電圧位相補正値を時間と共に徐々に減少させて最終的に零にするような電圧位相補正値）を加算して第３の電圧指令値を演算する手段と、
第３の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有し、
第２のトルク制御手段が、
前記電流検出値及び電動機定数からトルクを演算するトルク演算手段と、
前記トルク指令値と前記トルク演算値との偏差を増幅して前記電圧位相補正値を演算する電圧位相調節手段と、
第２の電圧指令値の位相に前記電圧位相補正値を加算して第３の電圧指令値を演算する手段と、
第３の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有し、
前記制御切換手段が、
第１のトルク制御手段の動作開始後に、前記電圧位相補正値を第２のトルク制御手段の動作時における値から時間と共に徐々に減少させて零にする機能と、を有するものである。
【００１５】
請求項４に記載した発明は、第１のトルク制御手段が、
前記電流指令値と前記電流検出値との偏差を増幅して電圧補正値を演算する電流調節手段と、第１の電圧指令値に前記電圧補正値を加算して第２の電圧指令値を演算する手段と、
第２の電圧指令値の位相に電圧位相補正値（第２のトルク制御手段の動作時における電圧位相補正値を時間と共に徐々に減少させて最終的に零にするような電圧位相補正値）を加算して第３の電圧指令値を演算する手段と、
第３の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有し、
第２のトルク制御手段が、
前記電流検出値及び電動機定数からトルクを演算するトルク演算手段と、
前記トルク指令値と前記トルク演算値との偏差を増幅して前記電圧位相補正値を演算する電圧位相調節手段と、
第１の電圧指令値に前記電圧補正値（第１のトルク制御手段の動作時における電圧補正値であって、後述するメモリに記憶された値）を加算して第２の電圧指令値を演算する手段と、
第２の電圧指令値の位相に前記電圧位相補正値を加算して第３の電圧指令値を演算する手段と、
第３の電圧指令値に基づいて電力変換器に対する駆動信号を生成する手段と、を有し、
前記制御切換手段が、
第２のトルク制御手段の動作開始時に第１のトルク制御手段の動作時における前記電圧補正値をメモリに記憶する機能と、第２のトルク制御手段の動作時における前記電圧補正値を前記メモリに記憶された値に制御する機能と、第１のトルク制御手段の動作を開始する前に、前記電流調節手段の出力を前記メモリに記憶された値にプリセットする機能と、
第１のトルク制御手段の動作開始後に、前記電圧位相補正値を第２のトルク制御手段の動作時における値から時間と共に徐々に減少させて零にする機能と、を有するものである。
【００１６】
【発明の実施の形態】
以下、図に沿って本発明の実施形態を説明する。
図１は、本発明の第１実施形態を示す制御ブロック図である。
図１において、１０１はトルク指令値τ^＊から所望のトルクが得られるような直軸電流指令値ｉ_ｄ ^＊及び横軸電流指令値ｉ_ｑ ^＊を演算する電流指令演算器、１１０は、前記各指令値ｉ_ｄ ^＊，ｉ_ｑ ^＊と速度検出回路１０７からの速度検出値ωと電動機定数（電機子抵抗、直軸・横軸インダクタンス、永久磁石鎖交磁束）とから、第１の直軸電圧指令値ｖ_ｄ１ ^＊及び第１の横軸電圧指令値ｖ_ｑ１ ^＊を数式１、数式２に従って演算する電圧指令演算器である。
【００１７】
［数１］
ｖ_ｄ１ ^＊＝Ｒ_ａｉ_ｄ ^＊−ωＬ_ｑｉ_ｑ ^＊
【００１８】
［数２］
ｖ_ｑ１ ^＊＝Ｒ_ａｉ_ｑ ^＊＋ωＬ_ｄｉ_ｄ ^＊＋ωΨ_ｍ
【００１９】
数式１，数式２において、Ｒ_ａ：電機子抵抗、Ｌ_ｄ：直軸インダクタンス、Ｌ_ｑ：横軸インダクタンス、Ψ_ｍ：永久磁石鎖交磁束である。
【００２０】
１０２ｄは直軸電圧補正値ｖ_ｄａｃｒを演算する直軸電流調節器、１０２ｑは横軸電圧補正値ｖ_ｑａｃｒを演算する横軸電流調節器、１０３は、第１の直軸電圧指令値ｖ_ｄ１ ^＊及び第１の横軸電圧指令値ｖ_ｑ１ ^＊に前記電圧補正値ｖ_ｄａｃｒ，ｖ_ｑａｃｒをそれぞれ加算して得た第２の直軸電圧指令値ｖ_ｄ２ ^＊及び第２の横軸電圧指令値ｖ_ｑ２ ^＊が入力され、極座標変換により電圧振幅指令値Ｖ^＊及び電圧位相指令φ_０を出力する極座標変換器である。
ここで、電圧補正値ｖ_ｄａｃｒ，ｖ_ｑａｃｒは、後述する如く制御切換信号が“１”の時には何れも零（各調節器１０２ｄ，１０２ｑが演算停止）となるので、その場合には、極座標変換器１０３に第１の直軸電圧指令値ｖ_ｄ１ ^＊及び第１の横軸電圧指令値ｖ_ｑ１ ^＊がそのまま入力されると考えることができる。
【００２１】
１０４は、電圧振幅指令値Ｖ^＊と、電圧位相指令φ_０に電圧位相補正値φ_ｖｐｈを加算して得た電圧位相指令φとを、磁極位置検出値θに基づき座標変換して三相電圧指令値ｖ_ｕ ^＊，ｖ_ｖ ^＊，ｖ_ｗ ^＊を出力する座標変換器、１０５は三相電圧指令値ｖ_ｕ ^＊，ｖ_ｖ ^＊，ｖ_ｗ ^＊をキャリアと比較してゲート信号を生成するＰＷＭ回路、２００はインバータ等の電力変換器、３００は制御対象である永久磁石同期電動機、１０６は同期電動機３００の回転子に取り付けられたパルスジェネレータ、１０７は速度検出回路、１０８は磁極位置検出回路、１０９は、Ｕ相電流検出値ｉ_ｕ、Ｗ相電流検出値ｉ_ｗ及び磁極位置検出値θから直軸電流検出値ｉ_ｄ及び横軸電流検出値ｉ_ｑを演算する座標変換器である。
上記電圧位相補正値φ_ｖｐｈは、後述する如く制御切換信号が“０”の時には零（電圧位相調節器１１２が演算停止）となるので、その場合には、極座標変換器１０３からの電圧位相指令φ_０がそのまま座標変換器１０４に入力されると考えることができる。
【００２２】
次に、１１１は、第１のトルク制御手段の動作と第２のトルク制御手段の動作とを切り換えるための制御切換信号を、電圧振幅指令値Ｖ^＊の大きさに応じて出力する制御切換器である。
ここで、第１のトルク制御手段は、所望のトルクが得られる電流指令値に電流検出値が一致するように同期電動機３００の端子電圧を制御する機能を持ち、第２のトルク制御手段は、同期電動機３００のトルク演算値がトルク指令値に一致するように端子電圧の位相を制御する機能を持つ。
【００２３】
上記制御切換信号は、論理が“０”の時に第１のトルク制御手段を動作させ、論理が“１”の時に第２のトルク制御手段を動作させるものとする。具体的には、制御切換器１１１は電圧振幅指令値Ｖ^＊が所定の大きさ以下である時に制御切換信号“０”を出力して第１のトルク制御手段を動作させ、電圧振幅指令値Ｖ^＊が所定の大きさを越えた時に制御切換信号“１”を出力して第２のトルク制御手段を動作させる。
【００２４】
制御切換信号は、前記直軸電流調節器１０２ｄ、横軸電流調節器１０２ｑ及び電圧位相調節器１１２に加えられている。ここで、電圧位相調節器１１２は、トルク指令値τ^＊とトルク演算値τ_ｃａｌとの偏差を増幅して電圧位相補正値φ_ｖ _ｐｈを出力する。なお、制御切換信号が“０”の場合、電圧位相調節器１１２の出力は零となるように構成されている。
また、１１３は直軸電流検出値ｉ_ｄ、横軸電流検出値ｉ_ｑ及び電動機定数から数式３によりトルク演算値τ_ｃａｌを求めるトルク演算器である。数式３において、Ｐ_Ｆ：極対数である。
【００２５】
［数３］
τ_ｃａｌ＝Ｐ_Ｆ｛Ψ_ｍｉ_ｄ＋（Ｌ_ｄ−Ｌ_ｑ）ｉ_ｄｉ_ｑ｝
【００２６】
前述のように電圧振幅指令値Ｖ^＊の大きさに応じて第１，第２のトルク制御手段を切り換える結果、電動機端子電圧が低い低速運転時は、このときのトルク制御に適した第１のトルク制御手段によりトルク制御が実行され、電動機端子電圧が高い高速運転時や電動機端子電圧を電力変換器２００の最大出力電圧に制御する場合は、第２のトルク制御制御手段によりトルク制御が実行される。これにより、広い速度範囲にわたって正確で安定したトルク制御を実現することができる。
【００２７】
以下、第１，第２のトルク制御手段の動作を個別に説明する。
最初に、第１のトルク制御手段の動作を説明する。いま、同期電動機３００が低速運転されており、極座標変換器１０３から出力される電圧振幅指令値Ｖ^＊が所定の大きさ以下であって、制御切換器１１１からは制御切換信号“０”が出力されている。
【００２８】
直軸電流調節器１０２ｄは、直軸電流指令値ｉ_ｄ ^＊と直軸電流検出値ｉ_ｄとの偏差を増幅して直軸電圧補正値ｖ_ｄａｃｒを演算し、横軸電流調節器１０２ｑは、横軸電流指令値ｉ_ｑ ^＊と横軸電流検出値ｉ_ｑとの偏差を増幅して横軸電圧補正値ｖ_ｑａｃｒを演算する。その結果、第１の直軸電圧指令値ｖ_ｄ１ ^＊と直軸電圧補正値ｖ_ｄａｃｒとの和が第２の直軸電圧指令値ｖ_ｄ２ ^＊として算出され、第１の横軸電圧指令値ｖ_ｑ１ ^＊と横軸電圧補正値ｖ_ｑａｃｒとの和が第２の横軸電圧指令値ｖ_ｑ２ ^＊として算出される。
これらの第２の直軸電圧指令値ｖ_ｄ２ ^＊及び横軸電圧指令値ｖ_ｑ２ ^＊は極座標変換器１０３に入力され、電圧振幅指令値Ｖ^＊及び電圧位相指令φ_０が演算される。
【００２９】
いま、制御切換信号は“０”であるため、電圧位相調節器１１２の出力である電圧位相補正値φ_ｖｐｈは零となっており、電圧位相調節器１１２の影響を受けることなく、電圧指令位相φとしては電圧位相指令φ_０がそのまま座標変換器１０４に入力される。
座標変換器１０４は、電圧振幅指令値Ｖ^＊、電圧指令位相φ及び磁極位置検出値θから三相電圧指令値ｖ_ｕ ^＊，ｖ_ｖ ^＊，ｖ_ｗ ^＊を演算する。
【００３０】
ＰＷＭ回路１０５及び電力変換器２００の動作は先に説明した図６の従来技術と同じであるため、説明を省略する。
上述した第１のトルク制御手段により、電流指令値に電流検出値が一致するように端子電圧を制御することで、低速運転時に同期電動機３００のトルクを指令値に制御することができる。
【００３１】
次に、第２のトルク制御手段の動作を説明する。この状態は電動機端子電圧が高い高速運転時や電動機端子電圧を電力変換器２００の最大出力電圧に制御する場合であり、極座標変換器１０３から出力されている電圧振幅指令値Ｖ^＊が所定の大きさを越えているため、制御切換器１１１からは制御切換信号“１”が出力されている。
【００３２】
このとき、直軸電流調節器１０２ｄの出力である直軸電圧補正値ｖ_ｄａｃｒと横軸電流調節器１０２ｑの出力である横軸電圧補正値ｖ_ｑａｃｒとは、何れも零となっている。この結果、ｖ_ｄ２ ^＊，ｖ_ｑ２ ^＊はそれぞれｖ_ｄ１ ^＊，ｖ_ｑ１ ^＊に等しくなるので、ｖ_ｄ２ ^＊とｖ_ｑ２ ^＊とから極座標変換器１０３により演算されるＶ^＊とφ_０は、電流指令値ｉ_ｄ ^＊，ｉ_ｑ ^＊、速度検出値ω及び電動機定数を使ってオープンループで演算した値となる。
【００３３】
一方、トルク演算器１１３は、前述した数式３によりトルク演算値τ_ｃａｌを求める。また、電圧位相調節器１１２は、トルク指令値τ^＊とトルク演算値τ_ｃａｌとの偏差を増幅して電圧位相補正値φ_ｖｐｈを演算する。
そして、電圧位相指令φ_０と電圧位相補正値φ_ｖｐｈとを加算して電圧指令位相φを演算し、座標変換器１０４では、Ｖ^＊，φ及び磁極位置検出値θから三相電圧指令値ｖ_ｕ ^＊，ｖ_ｖ ^＊，ｖ_ｗ ^＊を演算する。
ここで、上記Ｖ^＊及びφは、請求項１における第３の電圧指令値を構成するものである。
以上の制御を行うことにより、高速運転時等においては、電圧位相が適切な値に制御されてトルクを指令値に制御することができる。
【００３４】
次に、図２は本発明の第２実施形態を示す制御ブロック図である。
この実施形態は、図１の機能に、第１のトルク制御手段と第２のトルク制御手段との間で制御を切り換えるときの電圧振幅指令値Ｖ^＊の変化をなくして切換ショックを低減する機能を加えたものである。
図１と同一の構成要素には同一の参照符号を付して説明を省略し、以下では図１と異なる部分を中心に説明する。
【００３５】
すなわち、直軸電流調節器１０２ｄから出力される直軸電圧補正値ｖ_ｄａｃｒは、スイッチＳＷ_２ｂｄを介して、または、スイッチＳＷ_１ｄ、第１のメモリ１１４ｄ及びスイッチＳＷ_２ａｄを介して、第１の直軸電圧指令値ｖ_ｄ１ ^＊に加算されるように構成されている。また、第１のメモリ１１４ｄの出力はスイッチＳＷ_３ｄを介して直軸電流調節器１０２ｄにプリセットされるようになっている。同様にして、横軸電流調節器１０２ｑから出力される横軸電圧補正値ｖ_ｑａｃｒは、スイッチＳＷ_２ｂｑを介して、または、スイッチＳＷ_１ｑ、第２のメモリ１１４ｑ及びスイッチＳＷ_２ａｑを介して、第１の横軸電圧指令値ｖ_ｑ１ ^＊に加算されるように構成されている。また、第２のメモリ１１４ｑの出力はスイッチＳＷ_３ｑを介して横軸電流調節器１０２ｑにプリセットされるようになっている。
【００３６】
更に、制御切換器１１１から出力される制御切換信号は、互いに連動するスイッチＳＷ_２ｂｄ，ＳＷ_２ａｄ，ＳＷ_２ｂｑ，ＳＷ_２ａｑに加えられている。なお、スイッチＳＷ_２ｂｄ，ＳＷ_２ｂｑはいわゆるｂ接点動作し、スイッチＳＷ_２ａｄ，ＳＷ_２ａｑはいわゆるａ接点動作する。
また、制御切換信号はその立上がりを検出する立上がり検出手段１１５、立下がりを検出する立下がり検出手段１１６及び電圧位相調節器１１２に入力されている。そして、立上がり検出手段１１５の出力信号は互いに連動するスイッチＳＷ_１ｄ，ＳＷ_１ｑに加えられ、立下がり検出手段１１６の出力信号は互いに連動するスイッチＳＷ_３ｄ，ＳＷ_３ｑに加えられている。
【００３７】
この実施形態の動作を説明すると、まず、同期電動機３００が低速運転され、前記同様に制御切換器１１１からは制御切換信号“０”が出力されているとする。また、本実施形態でも、制御切換信号が“０”で第１のトルク制御手段を動作させ、“１”で第２のトルク制御手段を動作させるものとする。
【００３８】
制御切換信号“０”によってスイッチＳＷ_２ｂｄ，ＳＷ_２ｂｑを「閉」、スイッチＳＷ_２ａｄ，ＳＷ_２ａｑを「開」とすることにより、直軸電流調節器１０２ｄにより演算された電圧指令補正値ｖ_ｄａｃｒと、横軸電流調節器１０２ｑにより演算された電圧指令補正値ｖ_ｑａｃｒとが、第１の直軸電圧指令値ｖ_ｄ１ ^＊、第１の横軸電圧指令値ｖ_ｑ１ ^＊にそれぞれ加算される。
【００３９】
電圧振幅指令値Ｖ^＊が所定の大きさを越えた場合、制御切換信号が“０”から“１”に変化して第１のトルク制御手段による動作から第２のトルク制御手段による動作に切り換わる。
すなわち、“０”から“１”に変化する制御切換信号の立上がりを立上がり検出手段１１５が検出し、その出力信号によってスイッチＳＷ_１ｄ，ＳＷ_１ｑを「閉」とし、第１のトルク制御手段が動作中の直軸電圧補正値ｖ_ｄａｃｒ及び横軸電圧補正値ｖ_ｑａｃｒをそれぞれ第１のメモリ１１４ｄと第２のメモリ１１４ｑに記憶する。
【００４０】
第２のトルク制御手段による制御時には、制御切換信号“１”によってスイッチＳＷ_２ｂｄ，ＳＷ_２ｂｑを「開」、スイッチＳＷ_２ａｄ，ＳＷ_２ａｑを「閉」とし、直軸電圧補正値ｖ_ｄａｃｒ及び横軸電圧補正値ｖ_ｑａｃｒをメモリ１１４ｄ，１１４ｑに記憶した値に制御する。
【００４１】
また、電圧振幅指令値Ｖ^＊が所定の大きさ以下になって第２のトルク制御手段による動作から第１のトルク制御手段による動作に切り換わるときには、“１”から“０”に変化する制御切換信号の立下がりを立下がり検出手段１１６が検出し、その出力信号によりスイッチＳＷ_３ｄ，ＳＷ_３ｑを「閉」とする。
これにより、直軸電流調節器１０２ｄの出力と横軸電流調節器１０２ｑの出力とをそれぞれメモリ１１４ｄ，１１４ｑに記憶した値にプリセットしてから、スイッチＳＷ_２ｂｄ，ＳＷ_２ｂｑを「閉」、スイッチＳＷ_２ａｄ，ＳＷ_２ａｑを「開」とし、直軸電流調節器１０２ｄと横軸電流調節器１０２ｑとを使って直軸電圧補正値ｖ_ｄａｃｒ及び横軸電圧補正値ｖ_ｑａｃｒを演算する。
【００４２】
以上のような切換時の演算処理を行うことにより、第１及び第２のトルク制御手段によるトルク制御の切換前後で電圧振幅指令値を同じ値にすることができるので、切換ショックが発生しなくなる。
【００４３】
次いで、図３は本発明の第３実施形態を示す制御ブロック図である。
この実施形態は、図１の機能に、第１のトルク制御手段と第２のトルク制御手段との間で制御を切り換えるときの電圧位相指令φの変化を滑らかにして切換ショックを低減する機能を加えたものである。
【００４４】
すなわち図３の実施形態では、電圧位相調節器１１２の出力側に電圧位相つなぎ制御器１１７を追加し、制御切換信号をこの電圧位相つなぎ制御器１１７にも入力している。その他の構成は図１と同様である。なお、電圧位相つなぎ制御器１１７の入力信号（電圧位相調節器１１２の出力である電圧位相補正値）をφ_ｖｐｈ０とする。
【００４５】
図５は電圧位相つなぎ制御器１１７の入出力波形を示しており、これを使って動作を説明する。
図５に示すように、制御切換信号が時刻ｔ１で“１”から“０”に切り換わって第１のトルク制御手段による制御が開始されると、電圧位相調節器１１２から出力される電圧位相補正値φ_ｖｐｈ０を零にするが、電圧位相つなぎ制御器１１７から出力される電圧位相補正値φ_ｖｐｈは、第２のトルク制御手段による制御を実行中のφ_ｖｐｈ０の値から、時間経過と共に緩やかに減少させて最終的に零にする。
このように動作する電圧位相つなぎ制御器１１７を設けることにより、電圧位相の変化を緩やかにすることができ、トルク制御手段を切り換えるときのショックを低減することができる。
【００４６】
図４は、本発明の第４実施形態を示す制御ブロック図である。
この実施形態は、第１実施形態に第２，第３実施形態におけるトルク制御手段切り換え時のショック低減機能を追加したもので、制御ブロックの構成上は図２の構成に図３の電圧位相つなぎ制御器１１７を付加したものに相当する。
動作としては第１〜第３実施形態により説明した動作と同じであるため、説明を省略する。
【００４７】
【発明の効果】
以上のように本発明によれば、第１，第２のトルク制御手段を備え、同期電動機の運転状態に応じて所定のトルク制御手段を選択して動作させるようにしたため、同期電動機の広い速度範囲にわたって適切なトルク制御を実現し、これと同時に効率の向上や機器容量の低減を可能にするものである。
【図面の簡単な説明】
【図１】本発明の第１実施形態の制御ブロック図である。
【図２】本発明の第２実施形態の制御ブロック図である。
【図３】本発明の第３実施形態の制御ブロック図である。
【図４】本発明の第４実施形態の制御ブロック図である。
【図５】電圧位相つなぎ制御器の動作を示すタイミングチャートである。
【図６】従来技術の制御ブロック図である。
【符号の説明】
１０１　電流指令演算器
１０２ｄ　直軸電流調節器
１０２ｑ　横軸電流調節器
１０３　極座標変換器
１０４，１０９　座標変換器
１０５　ＰＷＭ回路
１０６　パルスジェネレータ
１０７　速度検出回路
１０８　磁極位置検出回路
１１０　電圧指令演算器
１１１　切換制御器
１１２　電圧位相調節器
１１３　トルク演算器
１１４ｄ，１１４ｑ　メモリ
１１５　立上がり検出手段
１１６　立下がり検出手段
１１７　電圧位相つなぎ制御器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for driving a synchronous motor such as a permanent magnet type synchronous motor with a power converter, and more particularly, to a control device characterized by a torque control unit.
[0002]
[Prior art]
FIG. 6 shows a control block diagram of a conventional permanent magnet synchronous motor.
In the figure, current command calculator 101 obtains a desired torque based on torque command value τ ^* and speed detection value ω under the condition that the terminal voltage of synchronous motor 300 does not exceed the maximum output voltage of power converter 200. The direct axis current command value _id ^* and the horizontal axis current command value _iq ^* are calculated. The configuration and operation of the current command calculator 101 are described in, for example, p. 1257.
The speed detection value ω is detected by the speed detection circuit 107 from an output pulse of the pulse generator 106 attached to the rotor of the synchronous motor 300.
[0003]
Direct axis current regulator 102d amplifies the deviation between the direct axis current command value i _d ^* and the direct-axis current detection value i _d calculates the direct axis voltage command value v _d ^*, the horizontal axis current regulator 102q is calculates a horizontal-axis voltage command value v _q ^* by amplifying the difference between the horizontal-axis current command value i _q ^* and the quadrature axis current detection value i _q. The detected direct-axis current value _id and detected horizontal-axis current value _iq are calculated by the coordinate converter 109 from the U-phase current detected value i _u , the W-phase current detected value i _w and the magnetic pole position detected value θ of the synchronous motor 300. I do. The magnetic pole position detection value θ is detected by the magnetic pole position detection circuit 108 from the output pulse of the pulse generator 106.
[0004]
The polar coordinate converter 103 calculates a voltage amplitude command value V ^* and a voltage phase command φ ₀ from the direct axis voltage command value v _d ^* and the horizontal axis voltage command value v _q ^* , and the coordinate converter 104 calculates the voltage amplitude command value. The three-phase voltage command values v _u ^* , v _v ^* , v _w ^* are calculated from V ^* , the voltage phase command φ ₀ and the magnetic pole position detection value θ. These three-phase voltage command values v _u ^* , v _v ^* , v _w ^* are pulse width modulated by the PWM circuit 105 to generate a gate signal of the power converter 200, and the gate signal of the power converter 200 is generated using the gate signal. By driving the switching element, the terminal voltage of the synchronous motor 300 is controlled, and by controlling the current of the synchronous motor 300 to the command value, the torque is controlled to the command value.
This control method has a feature that accurate torque control is possible even at low speeds including zero speed of the synchronous motor 300.
[0005]
[Problems to be solved by the invention]
In order to operate the synchronous motor with high efficiency or to reduce the capacity of the device including the synchronous motor and the power converter, it is desirable that the terminal voltage of the motor can be controlled up to the maximum output voltage of the power converter.
However, in the conventional control method shown in FIG. 6, since the terminal voltage is controlled by feeding back the current detection value, if the motor terminal voltage is controlled to the maximum output voltage of the power converter, the voltage is set to the command value. Even if the current regulators 102d and 102q output the voltage command values v _d ^* and v _q ^* so as to stabilize the current control system, the actual motor terminal voltage does not become the same as the command value. There is a problem that the stability of the control system is reduced.
[0006]
The natural frequency corresponding to the speed of the synchronous motor is equal to the output frequency of the power converter, while the response of the current control system is proportional to the current sampling frequency.
When a digital controller is used, the ratio between the output frequency of the power converter and the sampling frequency decreases as the speed of the synchronous motor increases, so that the oscillation of the natural frequency component of the synchronous motor cannot be reduced by the operation of the current regulator, As a result, the stability of the current control system is reduced. Therefore, there is a problem that the maximum speed of the synchronous motor must be limited in order to maintain the stability.
[0007]
As means for solving the above-mentioned problems, there is known a control device for a permanent magnet synchronous motor for driving a vehicle described in JP-A-10-14273.
In this control device, as shown in FIG. 1, a voltage command value is calculated from a current command value, a speed detection value, and a motor constant, and a torque calculation value calculated from the voltage command value, the current detection value, and the motor constant is a torque. The torque control is realized by calculating a torque angle correction value so as to match the command value, and controlling the phase of the voltage command value by the correction value.
[0008]
According to this control device, torque control can be performed by controlling the phase of the voltage. Therefore, when the motor terminal voltage is controlled to the maximum output voltage of the power converter, torque control is easy, and the current control system There is no problem such as a decrease in the stability of the device or a limitation on the maximum speed.
However, torque control by controlling the voltage phase by the control device described in Japanese Patent Application Laid-Open No. H10-14273 is a method that can be realized when the voltage drop due to the armature resistance is sufficiently smaller than the motor terminal voltage. When the motor is operated at a low speed, the voltage drop due to the armature resistance cannot be ignored and there is another problem that torque control becomes difficult.
[0009]
Therefore, an object of the present invention is to provide a control device for a synchronous motor capable of realizing torque control in a wide speed range from low speed operation to high speed operation.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, according to the present invention, first torque control means for controlling a terminal voltage of a synchronous motor so that a current detection value matches a current command value for obtaining a desired torque; And a second torque control means for controlling the phase of the terminal voltage so that a torque calculation value calculated from the constant and the torque command value coincides with the torque command value, wherein the first torque control means and the second torque The control means is switched.
[0011]
As described above as the prior art, the torque control by the first torque control means can perform accurate torque control even at a low speed operation, but has a disadvantage that it is not good at a high speed operation. On the other hand, the torque control by the second torque control means is easy for torque control even when the motor terminal voltage is controlled to the maximum output voltage of the power converter. It is advantageous, but has the disadvantage that control is difficult during low speed operation with low motor terminal voltage.
Therefore, the present invention realizes torque control over a wide speed range by combining the two torque control methods, and at the same time, it is possible to improve efficiency and reduce equipment capacity.
[0012]
That is, according to the present invention, a synchronous motor controls a synchronous motor by generating a current command value from a torque command value for the synchronous motor and operating a power converter based on a voltage command value generated from the current command value. In the control device of
Current command calculating means for calculating the current command value,
Voltage command calculating means for calculating a first voltage command value from the current command value, the detected speed value of the synchronous motor and the motor constant;
First torque control means for controlling a terminal voltage of the synchronous motor based on a first voltage command value such that a current detection value matches the current command value;
Second torque control means for controlling the phase of the terminal voltage so that the torque calculation value of the synchronous motor matches the torque command value;
Control switching means for switching and operating the first or second torque control means according to the operation state of the synchronous motor;
With
The first torque control means includes:
Current adjusting means for amplifying a deviation between the current command value and the current detection value to calculate a voltage correction value, and calculating a second voltage command value by adding the voltage correction value to a first voltage command value Means to
Means for generating a drive signal for the power converter based on the second voltage command value,
The second torque control means includes:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjustment means for amplifying a deviation between the torque command value and the torque calculation value to calculate a voltage phase correction value,
Means for calculating the third voltage command value by adding the voltage phase correction value to the phase of the first voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value.
[0013]
According to a second aspect of the present invention, the first torque control means includes:
Current adjusting means for amplifying a deviation between the current command value and the current detection value to calculate a voltage correction value, and calculating a second voltage command value by adding the voltage correction value to a first voltage command value Means to
Means for generating a drive signal for the power converter based on the second voltage command value,
The second torque control means is:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjustment means for amplifying a deviation between the torque command value and the torque calculation value to calculate a voltage phase correction value,
A second voltage command value is calculated by adding the voltage correction value (a voltage correction value during operation of the first torque control means and stored in a memory described later) to the first voltage command value. Means to
Means for calculating a third voltage command value by adding the voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The control switching means,
A function of storing the voltage correction value at the time of operation of the first torque control means in the memory at the start of operation of the second torque control means, and a function of storing the voltage correction value at the time of operation of the second torque control means in the memory. It has a function of controlling to a stored value and a function of presetting the output of the current adjusting means to a value stored in the memory before starting the operation of the first torque control means. is there.
[0014]
According to a third aspect of the present invention, the first torque control means includes:
Current adjusting means for amplifying a deviation between the current command value and the current detection value to calculate a voltage correction value, and calculating a second voltage command value by adding the voltage correction value to a first voltage command value Means to
A voltage phase correction value (a voltage phase correction value such that the voltage phase correction value during the operation of the second torque control means is gradually reduced with time to finally become zero) is used as the phase of the second voltage command value. Means for adding and calculating a third voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The second torque control means is:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjusting means for amplifying a deviation between the torque command value and the torque calculation value to calculate the voltage phase correction value,
Means for calculating a third voltage command value by adding the voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The control switching means,
After the operation of the first torque control means is started, the voltage phase correction value is gradually reduced from the value at the time of operation of the second torque control means with time to zero.
[0015]
According to a fourth aspect of the present invention, the first torque control means includes:
Current adjusting means for amplifying a deviation between the current command value and the current detection value to calculate a voltage correction value, and calculating a second voltage command value by adding the voltage correction value to a first voltage command value Means to
A voltage phase correction value (a voltage phase correction value such that the voltage phase correction value during the operation of the second torque control means is gradually reduced with time to finally become zero) is used as the phase of the second voltage command value. Means for adding and calculating a third voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The second torque control means is:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjusting means for amplifying a deviation between the torque command value and the torque calculation value to calculate the voltage phase correction value,
A second voltage command value is calculated by adding the voltage correction value (a voltage correction value during operation of the first torque control means and stored in a memory described later) to the first voltage command value. Means to
Means for calculating a third voltage command value by adding the voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The control switching means,
A function of storing the voltage correction value at the time of operation of the first torque control means in the memory at the start of operation of the second torque control means, and a function of storing the voltage correction value at the time of operation of the second torque control means in the memory. A function of controlling to a stored value, a function of presetting an output of the current adjusting means to a value stored in the memory before starting an operation of the first torque control means,
After the operation of the first torque control means is started, the voltage phase correction value is gradually reduced from the value at the time of operation of the second torque control means with time to zero.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a control block diagram showing a first embodiment of the present invention.
In FIG. 1, reference numeral 101 denotes a current command calculator for calculating a direct axis current command value _id ^* and a horizontal axis current command value _iq ^* such that a desired torque can be obtained from the torque command value τ ^*. From the command values _id ^* , _iq ^* , the speed detection value ω from the speed detection circuit 107, and the motor constants (armature resistance, direct / horizontal axis inductance, permanent magnet interlinkage magnetic flux), the first direct-axis voltage This is a voltage command calculator that calculates the command value v _d1 ^* and the first horizontal axis voltage command value v _q1 ^{* according} to Equations 1 and 2.
[0017]
[Equation 1]
_{^{_{_{^{v d1 * = R a i d}}}}} * -ωL q i q *
[0018]
[Equation 2]
_{^{_{_{^{v q1 * = R a i q}}}}} * + ωL d i d * + ωΨ m
[0019]
Equation 1, in formulas 2, _{R a:} armature resistance, _{L d:} direct-axis inductance, _{L q:} horizontal axis inductance, [psi _m: a permanent magnet flux linkage.
[0020]
_{Reference numeral} 102d denotes a direct-axis current controller that calculates a direct-axis voltage correction value v _dacr , 102q denotes a horizontal-axis current controller that calculates a horizontal-axis voltage correction value v _qacr , and 103 denotes a first direct-axis voltage command value v _d1 ^*. and said voltage correction value to the first transverse axis voltage command value _{v q1} ^* _v _{DACR, v} second direct axis voltage command value obtained by adding each _qacr _{v d2} ^* and a second horizontal axis voltage command value v _q2 ^* is input, a polar coordinate converter for outputting a voltage amplitude command value V ^* and the voltage phase command phi ₀ through polar coordinate conversion.
Here, as described later, the voltage correction values v _dacr and v _qaccr are both zero when the control switching signal is “1” (the respective regulators 102 d and 102 q stop calculation). In this case, the polar coordinate conversion is performed. It can be considered that the first direct-axis voltage command value v _d1 ^* and the first horizontal-axis voltage command value v _q1 ^* are directly input to the unit 103.
[0021]
A three-phase voltage conversion unit 104 performs coordinate conversion of the voltage amplitude command value V ^* and the voltage phase command φ obtained by adding the voltage phase correction value φ _vph to the voltage phase command φ ₀ based on the magnetic pole position detection value θ. command value _{^{_{^{_{v u *, v v *,}}}}} v coordinate converter that outputs ^{w *,} 105 are three-phase voltage command values _{^{_{^{_{v u *, v v *,}}}}} v w * a PWM for generating a gate signal by comparing the carrier Circuit, 200 is a power converter such as an inverter, 300 is a permanent magnet synchronous motor to be controlled, 106 is a pulse generator attached to the rotor of the synchronous motor 300, 107 is a speed detection circuit, 108 is a magnetic pole position detection circuit, 109 is a coordinate converter for calculating a U-phase current detection value i _u, W-phase current detection value i _w and the direct-axis current detection value from the magnetic pole position detection value theta i _d and quadrature axis current detection value i _q.
The voltage phase correction value φ _vph becomes zero (the operation of the voltage phase adjuster 112 is stopped) when the control switching signal is “0” as described later. In this case, the voltage phase command from the polar coordinate converter 103 is used. It can be considered that φ ₀ is input to the coordinate converter 104 as it is.
[0022]
Next, a control switch 111 outputs a control switching signal for switching between the operation of the first torque control means and the operation of the second torque control means in accordance with the magnitude of the voltage amplitude command value V ^*. It is.
Here, the first torque control means has a function of controlling the terminal voltage of the synchronous motor 300 so that the current detection value matches a current command value at which a desired torque is obtained, and the second torque control means It has a function of controlling the phase of the terminal voltage so that the torque calculation value of the synchronous motor 300 matches the torque command value.
[0023]
The control switching signal operates the first torque control means when the logic is "0", and operates the second torque control means when the logic is "1". Specifically, when the voltage amplitude command value V ^* is equal to or smaller than a predetermined value, the control switch 111 outputs the control switching signal “0” to operate the first torque control means, and the voltage amplitude command value V ^{When *} exceeds a predetermined value, a control switching signal "1" is output to operate the second torque control means.
[0024]
The control switching signal is applied to the direct axis current adjuster 102d, the horizontal axis current adjuster 102q, and the voltage phase adjuster 112. Here, the voltage phase adjuster 112 amplifies the deviation between the torque command value τ ^* and the calculated torque value τ _cal to output a voltage phase correction value φ _v _ph . When the control switching signal is “0”, the output of the voltage phase adjuster 112 is configured to be zero.
Also, 113 is a torque unit for obtaining a calculated torque tau _cal by the direct-axis current detection value i _d, the horizontal axis current detection value i _q) and (3 from the motor constant. In Equation 3, P _F is the number of pole pairs.
[0025]
[Equation 3]
_{_{_{τ cal = P F {Ψ m}}} i d + (L d -L q) i d i q}
[0026]
As described above, as a result of switching between the first and second torque control means according to the magnitude of the voltage amplitude command value V ^* , during low-speed operation with a low motor terminal voltage, the first torque control suitable for torque control at this time is performed. The torque control is performed by the torque control means, and in the case of high-speed operation in which the motor terminal voltage is high or when the motor terminal voltage is controlled to the maximum output voltage of the power converter 200, the torque control is performed by the second torque control control means. You. Thus, accurate and stable torque control can be realized over a wide speed range.
[0027]
Hereinafter, the operation of the first and second torque control means will be described individually.
First, the operation of the first torque control means will be described. Now, the synchronous motor 300 is operating at low speed, the voltage amplitude command value V ^* output from the polar coordinate converter 103 is equal to or smaller than a predetermined value, and the control switch 111 outputs a control switch signal “0”. Have been.
[0028]
Direct axis current regulator 102d amplifies the deviation between the direct axis current command value _i ^{d *} and the direct-axis current detection value _{i d} calculates the direct axis voltage correction value _{v DACR,} horizontal axis current regulator 102q is the deviation between the horizontal-axis current command value i _q ^* and the quadrature axis current detection value i _q amplifies calculates a horizontal-axis voltage correction value _v qacr. As a result, the sum of the first direct-axis voltage command value v _d1 ^* and the straight-axis voltage correction value v _dacr is calculated as the second direct-axis voltage command value v _d2 ^* , and the first horizontal-axis voltage command value v The sum of _q1 ^* and the horizontal axis voltage correction value v _qacr is calculated as a second horizontal axis voltage command value v _q2 ^* .
The second straight axis voltage value of v _d2 ^* and the horizontal-axis voltage command value v _q2 ^* is input to polar converter 103, a voltage amplitude command value V ^* and the voltage phase command phi ₀ is computed.
[0029]
Now, since the control switching signal is “0”, the voltage phase correction value φ _vph output from the voltage phase adjuster 112 is zero, and the voltage command phase is not affected by the voltage phase adjuster 112. As φ, the voltage phase command φ ₀ is directly input to the coordinate converter 104.
The coordinate converter 104 calculates three-phase voltage command values v _u ^* , v _v ^* , v _w ^* from the voltage amplitude command value V ^* , the voltage command phase φ, and the magnetic pole position detection value θ.
[0030]
The operations of the PWM circuit 105 and the power converter 200 are the same as those of the prior art shown in FIG.
By controlling the terminal voltage so that the current detection value matches the current command value by the first torque control means described above, the torque of the synchronous motor 300 can be controlled to the command value during low-speed operation.
[0031]
Next, the operation of the second torque control means will be described. This state is at the time of high-speed operation in which the motor terminal voltage is high or when the motor terminal voltage is controlled to the maximum output voltage of the power converter 200, and the voltage amplitude command value V ^* output from the polar coordinate converter 103 has a predetermined value. Therefore, the control switch 111 outputs a control switch signal “1”.
[0032]
At this time, the straight-axis voltage correction value v _dacr , which is the output of the straight-axis current regulator 102d, and the horizontal-axis voltage correction value v _qacr, which is the output of the horizontal-axis current regulator 102q, are both zero. As a _{_result, ^v} d2 _^*, ^v _q2 * Each _v ^d1 _{*, v q1} becomes equal to _{^*, v d2} ^* and _{v q2} ^* and ^{V *} and phi ₀ which is calculated by the polar converter 103 from a current command the value ⁱ _{d ^{_^*,}} i q _^*, a value calculated by the open loop with the speed detection value ω and the motor constant.
[0033]
On the other hand, the torque calculator 113 obtains the torque calculation value τ _cal by using the above-described Expression 3. Further, the voltage phase adjuster 112 calculates the voltage phase correction value φ _vph by amplifying the deviation between the torque command value τ ^* and the torque calculation value τ _cal .
Then, the voltage command phase φ is calculated by adding the voltage phase command φ ₀ and the voltage phase correction value φ _vph, and the coordinate converter 104 calculates the three-phase voltage command value v from V ^* , φ and the magnetic pole position detection value θ. _u _{^*, _^v} _v ^*, _v calculates the ^{w *.}
Here, V ^* and φ constitute the third voltage command value in claim 1.
By performing the above control, at the time of high-speed operation or the like, the voltage phase is controlled to an appropriate value, and the torque can be controlled to the command value.
[0034]
Next, FIG. 2 is a control block diagram showing a second embodiment of the present invention.
This embodiment has the function of reducing the switching shock by eliminating the change in the voltage amplitude command value V ^* when the control is switched between the first torque control means and the second torque control means, in addition to the function of FIG. Is added.
The same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted, and the following description will focus on portions different from FIG.
[0035]
That is, the direct-axis voltage correction value v _dacr output from the direct-axis current controller 102d is output to the first switch via the switch SW _2bd or via the switch SW _1d , the first memory 114d, and the switch SW _2ad . It is configured to be added to the direct-axis voltage command value v _d1 ^* . The output of the first memory 114d is preset to the direct-axis current controller 102d via the switch SW _3d . Similarly, the horizontal axis voltage correction value v _qacr output from the horizontal axis current controller 102q is output via the switch SW _2bq or via the switch SW _1q , the second memory 114q, and the switch SW _2aq . It is configured to be added to the horizontal axis voltage command value v _q1 ^* of 1. The output of the second memory 114q is adapted to be preset to the horizontal axis current regulator 102q via a switch _{SW 3q.}
[0036]
Further, the control switching signal output from the control switch 111 is applied to the switches SW _2bd , SW _2ad , SW _2bq , and SW _2aq which are interlocked with each other. The switches SW _2bd and SW _2bq operate at a so-called b-contact, and the switches SW _2ad and SW _2aq operate at a so-called a-contact.
Further, the control switching signal is input to rising detecting means 115 for detecting the rising, falling detecting means 116 for detecting the falling, and voltage phase adjuster 112. The output signal of the rise detection means 115 is applied to the switches SW _1d and SW _1q which are linked to each other, and the output signal of the fall detection means 116 is applied to the switches SW _3d and SW _3q which are linked to each other.
[0037]
The operation of this embodiment will be described. First, it is assumed that the synchronous motor 300 is operated at a low speed, and the control switching signal “0” is output from the control switching device 111 as described above. Also in the present embodiment, it is assumed that the first torque control means is operated when the control switching signal is “0”, and the second torque control means is operated when the control switching signal is “1”.
[0038]
By _setting the switches SW _2bd and SW _2bq to “closed” and the switches SW _2ad and SW _2aq to “open” by the control switching signal “0”, the voltage command correction value v _dacr calculated by the direct-axis current controller 102d and , The voltage command correction value v _qacr calculated by the horizontal axis current controller 102q is _added to the first direct axis voltage command value v _d1 ^* and the first horizontal axis voltage command value v _q1 ^* , respectively.
[0039]
When the voltage amplitude command value V ^* exceeds a predetermined value, the control switching signal changes from "0" to "1" and the operation is switched from the operation by the first torque control means to the operation by the second torque control means. Be replaced.
That is, the rise detection means 115 detects the rise of the control switching signal changing from “0” to “1”, and the switches SW _1d and SW _1q are closed by the output signal, and the first torque control means operates. The intermediate voltage correction value v _dacr and the horizontal axis voltage correction value v _qacr are stored in the first memory 114d and the second memory 114q, respectively.
[0040]
At the time of control by the second torque control means, the switches SW _2bd and SW _2bq are “opened” and the switches SW _2ad and SW _2aq are “closed” by the control switching signal “1”, and the direct-axis voltage correction value v _dacr and the horizontal axis are set. The voltage correction value v _qacr is controlled to a value stored in the memories 114d and 114q.
[0041]
Further, when the voltage amplitude command value V ^* becomes equal to or smaller than a predetermined value and switches from the operation by the second torque control means to the operation by the first torque control means, the control to change from "1" to "0". The fall detecting means 116 detects the fall of the switching signal, and closes the switches SW _3d and SW _{3q based} on the output signal.
Thus, after presetting the output of the direct-axis current controller 102d and the output of the horizontal-axis current controller 102q to the values stored in the memories 114d and 114q, the switches SW _2bd and SW _2bq are “closed” and the switch SW _2ad and SW _2aq are _set to “open”, and the direct-axis voltage correction value v _dacr and the horizontal-axis voltage correction value v _qacr are calculated using the direct-axis current controller 102d and the horizontal-axis current controller 102q.
[0042]
By performing the above-described arithmetic processing at the time of switching, the voltage amplitude command value can be set to the same value before and after the switching of the torque control by the first and second torque control means, so that switching shock does not occur. .
[0043]
Next, FIG. 3 is a control block diagram showing a third embodiment of the present invention.
This embodiment has a function of reducing the switching shock by smoothing the change of the voltage phase command φ when the control is switched between the first torque control means and the second torque control means, in addition to the function of FIG. In addition.
[0044]
That is, in the embodiment of FIG. 3, the voltage phase connection controller 117 is added to the output side of the voltage phase adjuster 112, and the control switching signal is also input to the voltage phase connection controller 117. Other configurations are the same as those in FIG. Note that the input signal of the voltage phase connection controller 117 (the voltage phase correction value output from the voltage phase adjuster 112) is _φvph0 .
[0045]
FIG. 5 shows input / output waveforms of the voltage / phase connection controller 117, and the operation will be described with reference to these waveforms.
As shown in FIG. 5, when the control switching signal is switched from “1” to “0” at time t1 and the control by the first torque control means is started, the voltage phase output from the voltage phase adjuster 112 is changed. Although the correction value φ _vph0 is _set to zero, the voltage phase correction value φ _vph output from the voltage phase connection controller 117 gradually decreases with time from the value of φ _vph0 during which the control by the second torque control unit is being executed. And finally to zero.
By providing the voltage phase connection controller 117 that operates as described above, the change in the voltage phase can be made gradual, and the shock when switching the torque control means can be reduced.
[0046]
FIG. 4 is a control block diagram showing a fourth embodiment of the present invention.
In this embodiment, a shock reduction function at the time of switching the torque control means in the second and third embodiments is added to the first embodiment. In terms of the configuration of the control block, the voltage phase connection shown in FIG. This corresponds to the addition of the controller 117.
The operation is the same as the operation described in the first to third embodiments, and the description is omitted.
[0047]
【The invention's effect】
As described above, according to the present invention, the first and second torque control means are provided, and the predetermined torque control means is selected and operated according to the operation state of the synchronous motor. It realizes appropriate torque control over the range, and at the same time, enables improvement of efficiency and reduction of equipment capacity.
[Brief description of the drawings]
FIG. 1 is a control block diagram according to a first embodiment of the present invention.
FIG. 2 is a control block diagram according to a second embodiment of the present invention.
FIG. 3 is a control block diagram according to a third embodiment of the present invention.
FIG. 4 is a control block diagram according to a fourth embodiment of the present invention.
FIG. 5 is a timing chart showing the operation of the voltage phase connection controller.
FIG. 6 is a control block diagram of a conventional technique.
[Explanation of symbols]
101 Current command calculator 102d Direct axis current controller 102q Horizontal axis current controller 103 Polar coordinate converters 104, 109 Coordinate converter 105 PWM circuit 106 Pulse generator 107 Speed detection circuit 108 Magnetic pole position detection circuit 110 Voltage command calculator 111 Switching control Unit 112 Voltage phase adjuster 113 Torque calculators 114d, 114q Memory 115 Rise detecting means 116 Fall detecting means 117 Voltage phase connection controller

Claims

A synchronous motor control device that generates a current command value from a torque command value for the synchronous motor and controls a synchronous motor by operating a power converter based on a voltage command value generated from the current command value,
Current command calculating means for calculating the current command value,
Voltage command calculating means for calculating a first voltage command value from the current command value, the detected speed value of the synchronous motor and the motor constant;
First torque control means for controlling a terminal voltage of the synchronous motor based on a first voltage command value such that a current detection value matches the current command value;
Second torque control means for controlling the phase of the terminal voltage so that the torque calculation value of the synchronous motor matches the torque command value;
Control switching means for switching and operating the first or second torque control means according to the operation state of the synchronous motor;
With
The first torque control means includes:
Current adjusting means for amplifying a deviation between the current command value and the current detection value to calculate a voltage correction value, and calculating a second voltage command value by adding the voltage correction value to a first voltage command value Means to
Means for generating a drive signal for the power converter based on the second voltage command value,
The second torque control means includes:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjustment means for amplifying a deviation between the torque command value and the torque calculation value to calculate a voltage phase correction value,
Means for calculating the third voltage command value by adding the voltage phase correction value to the phase of the first voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value.

A synchronous motor control device that generates a current command value from a torque command value for the synchronous motor and controls a synchronous motor by operating a power converter based on a voltage command value generated from the current command value,
Current command calculating means for calculating the current command value,
Voltage command calculating means for calculating a first voltage command value from the current command value, the detected speed value of the synchronous motor and the motor constant;
First torque control means for controlling a terminal voltage of the synchronous motor based on a first voltage command value such that a current detection value matches the current command value;
Second torque control means for controlling the phase of the terminal voltage so that the torque calculation value of the synchronous motor matches the torque command value;
Control switching means for switching and operating the first or second torque control means according to the operation state of the synchronous motor;
With
The first torque control means includes:
Current adjusting means for amplifying a deviation between the current command value and the current detection value to calculate a voltage correction value, and calculating a second voltage command value by adding the voltage correction value to a first voltage command value Means to
Means for generating a drive signal for the power converter based on the second voltage command value,
The second torque control means includes:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjustment means for amplifying a deviation between the torque command value and the torque calculation value to calculate a voltage phase correction value,
Means for calculating the second voltage command value by adding the voltage correction value to the first voltage command value;
Means for calculating a third voltage command value by adding the voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The control switching means,
A function of storing the voltage correction value at the time of operation of the first torque control means in the memory at the start of operation of the second torque control means, and a function of storing the voltage correction value at the time of operation of the second torque control means in the memory. A function of controlling to a stored value, a function of presetting an output of the current adjusting means to a value stored in the memory before starting an operation of the first torque control means,
A control device for a synchronous motor, comprising:

A synchronous motor control device that generates a current command value from a torque command value for the synchronous motor and controls a synchronous motor by operating a power converter based on a voltage command value generated from the current command value,
Current command calculating means for calculating the current command value,
Voltage command calculating means for calculating a first voltage command value from the current command value, the detected speed value of the synchronous motor and the motor constant;
First torque control means for controlling a terminal voltage of the synchronous motor based on a first voltage command value such that a current detection value matches the current command value;
Second torque control means for controlling the phase of the terminal voltage so that the torque calculation value of the synchronous motor matches the torque command value;
Control switching means for switching and operating the first or second torque control means according to the operation state of the synchronous motor;
With
The first torque control means includes:
Current adjusting means for calculating a voltage correction value by amplifying a deviation between the current command value and the current detection value,
Means for calculating the second voltage command value by adding the voltage correction value to the first voltage command value;
Means for calculating a third voltage command value by adding a voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The second torque control means includes:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjusting means for amplifying a deviation between the torque command value and the torque calculation value to calculate the voltage phase correction value,
Means for calculating a third voltage command value by adding the voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The control switching means,
After the operation of the first torque control means starts, a function of gradually decreasing the voltage phase correction value from the value at the time of operation of the second torque control means with time to zero.
A control device for a synchronous motor, comprising:

A synchronous motor control device that generates a current command value from a torque command value for the synchronous motor and controls a synchronous motor by operating a power converter based on a voltage command value generated from the current command value,
Current command calculating means for calculating the current command value,
Voltage command calculating means for calculating a first voltage command value from the current command value, the detected speed value of the synchronous motor and the motor constant;
First torque control means for controlling a terminal voltage of the synchronous motor based on a first voltage command value such that a current detection value matches the current command value;
Second torque control means for controlling the phase of the terminal voltage so that the torque calculation value of the synchronous motor matches the torque command value;
Control switching means for switching and operating the first or second torque control means according to the operation state of the synchronous motor;
With
The first torque control means includes:
Current adjusting means for calculating a voltage correction value by amplifying a deviation between the current command value and the current detection value,
Means for calculating the second voltage command value by adding the voltage correction value to the first voltage command value;
Means for calculating a third voltage command value by adding a voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The second torque control means includes:
Torque calculation means for calculating torque from the detected current value and the motor constant,
Voltage phase adjusting means for amplifying a deviation between the torque command value and the torque calculation value to calculate the voltage phase correction value,
Means for calculating the second voltage command value by adding the voltage correction value to the first voltage command value;
Means for calculating a third voltage command value by adding the voltage phase correction value to the phase of the second voltage command value;
Means for generating a drive signal for the power converter based on the third voltage command value,
The control switching means,
A function of storing the voltage correction value at the time of operation of the first torque control means in the memory at the start of operation of the second torque control means, and a function of storing the voltage correction value at the time of operation of the second torque control means in the memory. A function of controlling to a stored value, a function of presetting an output of the current adjusting means to a value stored in the memory before starting an operation of the first torque control means,
After the operation of the first torque control means starts, a function of gradually decreasing the voltage phase correction value from the value at the time of operation of the second torque control means with time to zero.
A control device for a synchronous motor, comprising: