JPH071992B2 - Control circuit for magnetic bearing - Google Patents

Control circuit for magnetic bearing

Info

Publication number
JPH071992B2
JPH071992B2 JP63101396A JP10139688A JPH071992B2 JP H071992 B2 JPH071992 B2 JP H071992B2 JP 63101396 A JP63101396 A JP 63101396A JP 10139688 A JP10139688 A JP 10139688A JP H071992 B2 JPH071992 B2 JP H071992B2
Authority
JP
Japan
Prior art keywords
signal
magnetic bearing
load coil
circuit
output
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP63101396A
Other languages
Japanese (ja)
Other versions
JPH01274635A (en
Inventor
益士郎 久谷
成幸 中田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsui Engineering and Shipbuilding Co Ltd
Original Assignee
Mitsui Engineering and Shipbuilding Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsui Engineering and Shipbuilding Co Ltd filed Critical Mitsui Engineering and Shipbuilding Co Ltd
Priority to JP63101396A priority Critical patent/JPH071992B2/en
Publication of JPH01274635A publication Critical patent/JPH01274635A/en
Publication of JPH071992B2 publication Critical patent/JPH071992B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406—Magnetic bearings
    • F16C32/044—Active magnetic bearings
    • F16C32/0444—Details of devices to control the actuation of the electromagnets

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mechanical Engineering (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
  • Motor Or Generator Frames (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、磁気力により回転軸を非接触状態で支持する
磁気軸受用制御回路に関するものである。TECHNICAL FIELD The present invention relates to a magnetic bearing control circuit for supporting a rotating shaft in a non-contact state by a magnetic force.

〔従来の技術〕[Conventional technology]

例えばモータなどの回転子を支持する軸受を、機械的に
支持するのではなく、磁気力、通常吸引力を回転軸に作
用させて空間を浮かせて支持する磁気軸受が開発されて
いることは周知である。この磁気軸受の磁気力を制御す
るには、通常作用させる磁気力に対応するパルス幅を与
えたパルス電流を磁気軸受の負荷コイルに与えることに
よって行なっている。For example, it is well known that magnetic bearings that support a rotor that supports a rotor such as a motor are supported not by mechanically supporting them but by floating a space by applying a magnetic force, usually a suction force, to a rotating shaft. Is. To control the magnetic force of the magnetic bearing, a pulse current having a pulse width corresponding to the magnetic force to be normally applied is applied to the load coil of the magnetic bearing.

即ち、前記制御は、通常は、正規の回転軸位置からの変
位を検出し、該変位検出信号に対応するパルス幅のパル
ス信号に変換し、前記磁気軸受の負荷コイルに与えるよ
うにしている。以下図によって従来の制御回路について
説明する。That is, the control normally detects the displacement from the normal rotational shaft position, converts the displacement detection signal into a pulse signal having a pulse width corresponding to the displacement detection signal, and applies the pulse signal to the load coil of the magnetic bearing. A conventional control circuit will be described below with reference to the drawings.

第２図は従来のパルス幅変調（以下PWMという）方式に
よる磁気軸受用制御回路の一例を示す概略の回路図であ
る。比較回路１において、設定値信号Viと磁気軸受を駆
動する出力に対応して帰還する帰還信号Vbとの比較を行
なって偏差信号Voを出力し、PWM変換回路２において上
記偏差信号Voに応じたパルス幅変換をした電界効果パワ
ートランジスタ（以下FETという）３のゲートＧに、パ
ルス幅変調信号Vxを入力し、第３図に示すようにt1→t2
がオン，t2→t3がオフ，t3→t4がオン……するFET3の駆
動を行なうことにより、前記オン時のパルス幅に応じた
磁力で回転軸を支持する。FIG. 2 is a schematic circuit diagram showing an example of a conventional magnetic bearing control circuit by a pulse width modulation (hereinafter referred to as PWM) system. In the comparison circuit 1, the set value signal Vi is compared with the feedback signal Vb that is fed back corresponding to the output that drives the magnetic bearing, and the deviation signal Vo is output, and the PWM conversion circuit 2 responds to the deviation signal Vo. The pulse width modulation signal Vx is input to the gate G of the pulse width converted field effect power transistor (hereinafter referred to as FET) 3, and as shown in FIG. 3, t 1 → t 2
Is turned on, t 2 → t 3 is turned off, t 3 → t 4 is turned on, etc. By driving the FET 3 , the rotating shaft is supported by the magnetic force according to the pulse width at the time of turning on.

例えば、このFET3のオン時には、電源Vccより電流i1が
磁気軸受の負荷コイル４のR1,FET3のドレインＤおよび
ソースＳを経て抵抗R2に流れ、この抵抗R2によって発生
する電圧Vb＝i1・R2が帰還電圧となって比較回路１に負
帰還し、設定値信号Viと帰還信号Vbとを比較するような
フィードバック増幅回路を構成している。For example, when the FET 3 is turned on, a current i 1 from the power supply Vcc flows to the resistor R 2 via R 1 of the load coil 4 of the magnetic bearing, the drain D and the source S of the FET 3, and the voltage Vb generated by the resistor R 2 is Vb = i 1 · R 2 serves as a feedback voltage, which is negatively fed back to the comparison circuit 1 to form a feedback amplification circuit for comparing the set value signal Vi with the feedback signal Vb.

〔発明が解決しようとする課題〕[Problems to be Solved by the Invention]

上記のような構成の従来の磁気軸受用制御回路では、FE
T3のオンよりオフに切替わる第３図のt2,t4時に、負荷
コイル４の自己インダクタンスによる誘導起電力によっ
てFET3のための保護ダイオードD1の順方向となるよう
な、矢印の方向の電流が過渡的に流れる。この自己誘導
作用による電流の作用で生じる負荷変動はフィードバッ
ク回路より絶縁されて帰還されないので、サーボ制御系
の安定性を失なわせ、負荷コイル４への出力が瞬時的に
不安定状態となるために、軸受部に不規則な振動が発生
するという問題がある。In the conventional magnetic bearing control circuit configured as described above, the FE
At the time of t 2 and t 4 in FIG. 3 when T3 is switched from ON to OFF, the protective diode D 1 for the FET 3 becomes forward due to the induced electromotive force due to the self-inductance of the load coil 4, The current flows transiently. Since the load fluctuation caused by the action of the current due to the self-induction effect is insulated from the feedback circuit and is not fed back, the stability of the servo control system is lost and the output to the load coil 4 becomes momentarily unstable. In addition, there is a problem that irregular vibration occurs in the bearing portion.

本発明は上記のような問題点を解消するためになされた
もので、FET3がオンよりオフへ移行するときに過渡的に
発生する軸受部の振動を防止できる磁気軸受用制御回路
を提供することを目的とする。The present invention has been made to solve the above problems, and provides a magnetic bearing control circuit capable of preventing the vibration of the bearing portion that transiently occurs when the FET 3 shifts from ON to OFF. With the goal.

〔課題を解決するための手段」 上記目的を達成するための本発明による磁気軸受用制御
回路は、検出抵抗と、差動増幅器と、比較回路と、PWM
変換回路と、スイッチング素子とを有する磁気軸受用制
御回路であって、検出抵抗は、回転軸の周囲に配設され
且つこの回転軸を非接触状態で支持する磁気軸受用電磁
石の負荷コイルに直列に接続され、差動増幅器は、検出
抵抗の端子間電圧を入力し、負荷コイルの電流に対応す
る帰還信号を出力し、比較回路は、設定値信号と差動増
幅器の出力信号とを入力し、両者の偏差信号を出力し、
PWM変換回路は、比較回路の出力信号を入力し、対応す
るパルス幅変調信号を出力し、スイッチング素子は、ト
ランジスタであり、PWM変換回路の出力信号を入力し
て、電源に接続され保護ダイオードを有する負荷コイル
をオン・オフ駆動するものである。[Means for Solving the Problems] A magnetic bearing control circuit according to the present invention for achieving the above-mentioned object includes a detection resistor, a differential amplifier, a comparison circuit, and a PWM.
A control circuit for a magnetic bearing having a conversion circuit and a switching element, wherein a detection resistor is arranged around a rotary shaft and is connected in series to a load coil of a magnetic bearing electromagnet that supports the rotary shaft in a non-contact state. The differential amplifier inputs the voltage across the terminals of the detection resistor, outputs a feedback signal corresponding to the current in the load coil, and the comparison circuit inputs the set value signal and the output signal of the differential amplifier. , Output the deviation signal of both,
The PWM conversion circuit inputs the output signal of the comparison circuit and outputs the corresponding pulse width modulation signal, and the switching element is a transistor, which inputs the output signal of the PWM conversion circuit and is connected to the power supply to connect the protection diode. The load coil included therein is driven on / off.

〔作用〕[Action]

本発明における出力帰還信号は、負荷コイルに直列に設
けた検出抵抗の端子間に生じる電圧値に基づいて比較回
路へ帰還するので、負荷コイルに流れる電流値の変動を
確実に帰還するサーボ制御となり、負荷コイルの電流が
オフ時に生じる自己誘導による瞬時的な電流変動にも対
応して安定な制御系を構成するので、軸受部の不安定な
振動の発生を防止する。Since the output feedback signal in the present invention is fed back to the comparison circuit based on the voltage value generated between the terminals of the detection resistor provided in series with the load coil, it becomes the servo control for reliably feeding back the fluctuation of the current value flowing in the load coil. Since a stable control system is configured to cope with a momentary current fluctuation due to self-induction that occurs when the load coil current is off, the occurrence of unstable vibration of the bearing portion is prevented.

〔実施例〕〔Example〕

以下、本発明の一実施例を図に基づいて説明する。第１
図において、符号1,2,3は第２図の従来例を示した同符
号の比較回路,PWM変換回路,FETのそれぞれと対応した同
一または相当部分である。負荷コイル４は直列に検出抵
抗Rdを設け、この検出抵抗RdのＡ端子と差動増幅器５の
正端子と、またＢ端子と負端子とをそれぞれ接続し、差
動増幅器５の出力端は、比較回路１の入力端へ帰還回路
にして接続している。An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, reference numerals 1, 2, and 3 are the same or corresponding portions corresponding to the comparison circuit, the PWM conversion circuit, and the FET of the same reference numerals shown in the conventional example of FIG. The load coil 4 is provided with a detection resistor Rd in series, the A terminal of the detection resistor Rd is connected to the positive terminal of the differential amplifier 5, and the B terminal is connected to the negative terminal of the differential amplifier 5, and the output terminal of the differential amplifier 5 is A feedback circuit is connected to the input terminal of the comparison circuit 1.

次に、上記のように構成されたこの発明による制御回路
における動作を説明する。比較回路１において、設定値
信号Viと差動増幅器５の出力である帰還信号Vbとを比較
して偏差信号Voを出力し、この偏差信号Voに基づいてPW
M変換回路２でパルス幅変換されたオン・オフ信号、即
ちパルス幅変調信号VxがFET3のゲートＧに入力し、FET3
がオン・オフ駆動する。FET3がオン時には電源Vccより
の電流i1が検出抵抗Rd,コイル抵抗R1,FET3のドレインD,
ソースＳを経て流れ、検出電圧Vd1＝i1・Rdが差動増幅器
５に入力し、その出力Vd1が比較回路に負帰還して設定
値信号Viと比較することになる。Next, the operation of the control circuit according to the present invention configured as described above will be described. In the comparison circuit 1, the set value signal Vi is compared with the feedback signal Vb which is the output of the differential amplifier 5 to output the deviation signal Vo, and the PW is generated based on the deviation signal Vo.
The ON / OFF signal pulse-width converted by the M conversion circuit 2, that is, the pulse-width modulation signal Vx is input to the gate G of the FET3, and the FET3
Drives on and off. FET3 current i 1 is the detection resistor Rd of the power source Vcc at the time of ON, the drain D of the coil resistance R 1, FET3,
The detection voltage Vd 1 = i 1 · Rd flows through the source S, is input to the differential amplifier 5, and its output Vd 1 is negatively fed back to the comparison circuit and compared with the set value signal Vi.

ここで、FET3がオンよりオフ状態へ移行すると、従来例
の動作と同様に負荷コイル４の自己インダクタンスによ
る誘導起電力が発生し、保護ダイオードD1の順方向回路
となる矢印で示す電流i2が流れ、検出電圧Vd2＝i2・Rdが
差動増幅器５に入力し、増幅された出力Vb2が比較回路
１に負帰還して設定値信号Viと比較するフィードバック
制御動作が行なわれる。Here, when the FET 3 shifts from the on state to the off state, an induced electromotive force due to the self-inductance of the load coil 4 is generated as in the operation of the conventional example, and a current i 2 indicated by an arrow forming a forward circuit of the protection diode D 1 is generated. , The detected voltage Vd 2 = i 2 · Rd is input to the differential amplifier 5, and the amplified output Vb 2 is negatively fed back to the comparison circuit 1 to perform a feedback control operation of comparing with the set value signal Vi.

従って、上記の制御系においては、負荷コイル４の負荷
電流の変動を確実に比較回路に帰還させるので、FET3の
オフ時直後の負荷変動による制御系の乱れのない、安定
した制御動作によって負荷コイル４を駆動することがで
きる。Therefore, in the above control system, since the fluctuation of the load current of the load coil 4 is surely fed back to the comparison circuit, the load coil can be stably controlled without the disturbance of the control system due to the load fluctuation immediately after the FET 3 is turned off. 4 can be driven.

なお、上記実施例ではFET3をスイッチング素子として構
成した例について述べたが、他のトランジスタ等による
スイッチング素子を使用して構成してもよく、また検出
電圧を差動増幅器５によって増幅し、これを負帰還する
ようにしたが、負荷コイル４の負荷変動を確実に帰還で
きる他の手段によっても、上記実施例と同様の効果を奏
する。In the above-mentioned embodiment, the example in which the FET 3 is configured as a switching element has been described, but it may be configured by using a switching element including another transistor, and the detected voltage is amplified by the differential amplifier 5 and Although the negative feedback is performed, the same effect as that of the above embodiment can be obtained by other means that can reliably feed back the load fluctuation of the load coil 4.

〔発明の効果〕〔The invention's effect〕

以上説明したように、本発明によれば制御時における負
荷コイルの負荷変動を確実に帰還できるサーボ制御系に
構成したので、FET等のスイッチング素子のオフ時直後
に生じる過渡的な制御の乱れのない、安定した磁気軸受
の駆動を行なうことができる。更に、負荷コイルの誘導
起電力を検出して比較回路に帰還させる検出系は、検出
抵抗と差動増幅器によって構成しているため、構造が簡
単で耐久性及び信頼性に優れており、しかも安価に製造
することができる。As described above, according to the present invention, since the servo control system that can reliably feed back the load fluctuation of the load coil during control is provided, the transient control disturbance that occurs immediately after the switching element such as FET is turned off. No, stable magnetic bearing can be driven. Furthermore, the detection system that detects the induced electromotive force of the load coil and feeds it back to the comparison circuit is composed of a detection resistor and a differential amplifier, so the structure is simple, excellent in durability and reliability, and inexpensive. Can be manufactured.

【図面の簡単な説明】[Brief description of drawings]

第１図は本発明の一実施例による磁気軸受用制御回路の
回路図、第２図は軸受の磁気軸受用制御回路の一例を示
す回路図、第３図はスイッチング素子（FET）の出力波
形例を示す図である。 １……比較回路、２……パルス幅変調（PWM）回路、３
……FET（スイッチング素子）、４……負荷コイル、５
……差動増幅器（増幅手段）、Rd……検出用抵抗、Vi…
…設定値信号、Vb……帰還信号。FIG. 1 is a circuit diagram of a magnetic bearing control circuit according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a magnetic bearing control circuit of a bearing, and FIG. 3 is an output waveform of a switching element (FET). It is a figure which shows an example. 1 ... Comparison circuit, 2 ... Pulse width modulation (PWM) circuit, 3
...... FET (switching element), 4 …… Load coil, 5
...... Differential amplifier (amplifying means), Rd …… Detection resistor, Vi…
… Set value signal, Vb …… Return signal.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】検出抵抗（Rd）と、差動増幅器（５）と、
比較回路（１）と、PWM変換回路（２）と、スイッチン
グ素子（３）とを有する磁気軸受用制御回路であって、 検出抵抗（Rd）は、回転軸の周囲に配設され且つこの回
転軸を非接触状態で支持する磁気軸受用電磁石の負荷コ
イル（４）に直列に接続され、 差動増幅器（５）は、検出抵抗（Rd）の端子間電圧を入
力し、負荷コイル（４）の電流（ｉ）に対応する帰還信
号（Vb）を出力し、 比較回路（１）は、設定値信号（Vi）と差動増幅器
（５）の出力信号（Vb）とを入力し、両者の偏差信号
（Vo）を出力し、 PWM変換回路（２）は、比較回路（１）の出力信号（V
o）を入力し、対応するパルス幅変調信号（Vx）を出力
し、 スイッチング素子（３）は、トランジスタであり、PWM
変換回路（２）の出力信号を入力して、電源（Vcc）に
接続され保護ダイオード（D1）を有する負荷コイル
（４）をオン・オフ駆動する 磁気軸受用制御回路。1. A detection resistor (Rd), a differential amplifier (5),
A magnetic bearing control circuit having a comparison circuit (1), a PWM conversion circuit (2), and a switching element (3), in which a detection resistor (Rd) is arranged around the rotation shaft and Connected in series to the load coil (4) of the magnetic bearing electromagnet that supports the shaft in a non-contact state, the differential amplifier (5) inputs the voltage across the terminals of the detection resistor (Rd) and loads the load coil (4). The feedback signal (Vb) corresponding to the current (i) is output, and the comparison circuit (1) inputs the set value signal (Vi) and the output signal (Vb) of the differential amplifier (5), The deviation signal (Vo) is output, and the PWM conversion circuit (2) outputs the output signal (V
o), outputs the corresponding pulse width modulation signal (Vx), and the switching element (3) is a transistor, PWM
A control circuit for a magnetic bearing that inputs the output signal of the conversion circuit (2) and turns on and off a load coil (4) that is connected to a power supply (Vcc) and has a protection diode (D 1 ).
JP63101396A 1988-04-26 1988-04-26 Control circuit for magnetic bearing Expired - Lifetime JPH071992B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP63101396A JPH071992B2 (en) 1988-04-26 1988-04-26 Control circuit for magnetic bearing

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP63101396A JPH071992B2 (en) 1988-04-26 1988-04-26 Control circuit for magnetic bearing

Publications (2)

Publication Number Publication Date
JPH01274635A JPH01274635A (en) 1989-11-02
JPH071992B2 true JPH071992B2 (en) 1995-01-11

Family

ID=14299575

Family Applications (1)

Application Number Title Priority Date Filing Date
JP63101396A Expired - Lifetime JPH071992B2 (en) 1988-04-26 1988-04-26 Control circuit for magnetic bearing

Country Status (1)

Country Link
JP (1) JPH071992B2 (en)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57145307A (en) * 1981-03-05 1982-09-08 Nippon Denso Co Ltd Driving apparatus for electromagnetic actuator
JPS57167517A (en) * 1981-04-09 1982-10-15 Toshiba Corp Magnetic bearing device of flywheel
JPS59103019A (en) * 1982-12-02 1984-06-14 Seiko Instr & Electronics Ltd Control circuit for magnetic bearing

Also Published As

Publication number Publication date
JPH01274635A (en) 1989-11-02

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