JP4143908B2 - Electric motor control device - Google Patents

Description

【０００４】
で定義し、速度検出器が断線していない場合は、両者の差を用いて誘導電動機パラメータの適応制御を実施し、速度検出器が断線した場合は、両者の差が実速度に比例して変化することを利用し、速度検出器の断線を検出する方法が提案されている。なお、
【０００５】
【数２】

【０００６】
は、モータ定数を用いてモータ磁束を演算し、検出電流との外積により
【０００７】
【数３】

【０００８】
を求めている。
【０００９】
【特許文献１】
実開平０２−７１２７３号公報
【００１０】
【特許文献２】
特開２００１−２４９１５４号公報
【００１１】
【発明が解決しようとする課題】
しかしながら、電動機が速度零の近傍であるゼロ速付近で駆動されている場合には、速度検出値のみで速度検出器の断線を判断する方法では、電動機速度が０である状態が断線していない正常時にも生じるので誤検出する可能性があった。
また、制御情報を用いた検出を行なう電動機の制御装置は、パラメータの適応制御の誤差信号を求める演算処理が複雑であり、ソフト処理時間に余裕のない制御装置の場合、演算処理が内蔵できず、簡単に適用できないという問題があった。
そこで、本発明はこのような問題点に鑑みてなされたものであり、電動機がゼロ速付近で駆動されている場合でも電動機に取りつけられたパルスエンコーダ等の速度検出器の断線を確実に検出でき、電動機の制御量を用いた簡単な演算を行なうことで、高価なＣＰＵを用いない制御装置にも適用することができる電動機の制御装置を提供することを目的とする。
【００１２】
【課題を解決するための手段】
上記問題を解決するため、本発明は、次のように構成したのである。
請求項１に記載の発明は、電動機に取りつけられた速度検出手段と、電動機の電圧、電流をｄ、ｑの２軸に座標変換して制御し、電圧、あるいは電流のｄ、ｑ成分から速度検出手段の断線を判断する断線検出手段を備えた電動機制御装置において、速度検出手段の断線検出手段は、上記ｄ、ｑ成分の値として、励磁電流方向電圧指令値Ｖｄ＊、トルク電流方向電圧指令値Ｖｑ＊を用い、θｖ＝ｔａｎ−１（Ｖｑ＊／Ｖｄ＊）を演算し、θｖが一定時間内に所定値以上変化したり、あるいはθｖが所定値から外れた値となったときに、速度検出手段の断線条件の１つが満足したと判断することを特徴とし、
【００１４】
請求項２に記載の発明は、ｄ、ｑ成分の値として、誘起電圧Ｅのｑ、ｄ軸成分をＥｑ、Ｅｄとして演算し、θｅ＝ｔａｎ−１（Ｅｑ／Ｅｄ）を演算し、θｅが一定時間内に所定値以上変化したり、あるいはθｅが所定値から外れた値となったときに、速度検出手段の断線条件の１つが満足したと判断することを特徴とし、
【００１５】
請求項３に記載の発明は、ｄ、ｑ成分の値として、トルク電流帰還値Ｉｑ、励磁電流帰還値Ｉｄを用い、θｉ＝ｔａｎ−１（Ｉｑ／Ｉｄ）を演算し、θｉが一定時間内に所定値以上変化したり、あるいはθｉが所定値から外れた値となったときに、速度検出手段の断線条件の１つが満足したと判断することを特徴とし、
【００１６】
請求項４に記載の発明は、ｄ、ｑ成分の値として、励磁電流方向電圧指令値Ｖｄ＊、トルク電流方向電圧指令値Ｖｑ＊を用い、Ｖｄ＊、Ｖｑ＊の符号が異なる状態のときに、速度検出手段の断線条件の１つが満足したと判断することを特徴とするものである。
このようになっているため、電動機の電圧、あるいは電流のｄ、ｑ成分から速度検出手段の断線を判断することができる。
【００１７】
【発明の実施の形態】
交流電動機を駆動する制御装置として、可変電圧可変周波数による速度制御が知られ、より高精度な制御するべく、交流電動機に供給される一次電流を励磁電流（磁束を発生させる電流）とトルク電流（トルクを発生させる電流）とに分けて制御し、二次磁束とトルク電流を常に直交するように制御することで、直流交流電動機と同等の応答性を得ることのできるベクトル制御方式が実用化されている。ベクトル制御方式は周知であるので、説明は省略する。
以下、本発明の具体的実施例を図に基づいて説明する。図１は、本発明の電動機制御装置のブロック図である。図において、電圧形インバータ１は直流電源１６から加えられる直流電圧をＰＷＭ制御方式により任意の周波数と電圧の交流に変換する。電圧形インバータ１の各相Ｕ、Ｖ、Ｗの交流出力端に交流電動機２、更に速度検出手段としての速度検出器１７が接続されている。交流電動機２の各相に流れる電流は電流検出手段としての電流検出器４-1〜４-3により検出される。
【００１８】
ベクトル制御装置３には、交流電動機２の一次電流を検出して座標変換を行ないトルク電流帰還値Ｉｑおよび励磁電流帰還値Ｉｄを送出するｄ−ｑ変換器５が設けられている。さらに、指令発生器１４から入力された速度指令値ωｒ*と速度検出器１７を入力とし速度を演算する速度演算器８からの速度検出値ωrが一致するように設けられた速度制御器（ＡＳＲ）１１の出力値をトルク電流指令値Ｉｑ*とし、このＩｑ*とｄ−ｑ変換器５が出力するトルク電流帰還値Ｉｑとが一致するように制御するためのトルク電流制御器（ＡＣＲｑ）７-1、磁束指令発生器９出力値を入力とした係数器１０で演算された励磁電流指令値Ｉｄ*とｄ−ｑ変換器５からの励磁電流帰還値Ｉｄとが一致するように制御するための励磁電流制御器（ＡＣＲｄ）７-2が設けられている。
【００１９】
交流電動機２で発生した誘起電圧Ｅ、一次抵抗ｒ１や漏れインダクタンスｌによる逆起電力の電圧を補償する回路は省略している。電圧指令演算器６では、トルク電流制御器７-1と、励磁電流制御器７-2の出力と、各逆起電力の電圧補償値との和を、積分器１２出力の位相θで座標変換し、Ｕ、Ｖ、Ｗ各相毎の電圧指令値を演算し、電圧指令ベクトルｖ1となる。
また、滑り周波数指令演算器１５は、磁束指令発生器９出力φ*、トルク電流指令値Ｉｑ*と設定された二次抵抗ｒ２（図示せず）から滑り周波数指令値ωｓ*を求め、加算器１３で速度演算器８からの速度検出値ωｒと加算して、一次周波数指令値ω₁*を演算し、積分器１２を介して位相θを演算する。
【００２０】
速度検出器断線検出回路１８は、トルク電流方向電圧指令値Ｖq*、励磁電流方向電圧指令値Ｖd*を成分にもつ電圧指令ｖ1（以下ｖ1と略しベクトルを表わすものとする）、トルク電流帰還値Ｉｑ、励磁電流帰還値Ｉｄを成分にもつ電流検出ベクトルｉ1（以下ｉ1と略しベクトルを表わすものとする）を入力値とし、速度検出器の断線を判断する。この検出方法については後述する。
ベクトル制御が成立しているとき、トルク電流方向電圧指令値Ｖq*とトルク電流方向電圧の実際値Ｖq、励磁電流方向電圧指令値Ｖd*と励磁電流方向電圧の実際値Ｖdは一致しているので、第１式、第２式が成立する。
【００２１】
Ｖｑ*＝Ｅ＋√３・ｒ１・Iq＋√３・ω₁*・ｌ・Id ＋ ＡＣＲｑ…（１）
Ｖｄ*＝√３・ｒ１・Id−√３・ω₁*・ｌ・Iq ＋ ＡＣＲｄ …（２）
なお、ＡＣＲｑ、ＡＣＲｄは、それぞれ、トルク電流制御器7-1と励磁電流制御器7-2出力値を示す。
【００２２】
ところが、速度検出器１７が断線状態になり、実速度はωrであるにも速度演算器８出力が０になると、電動機内には回転磁界が発生しているにも関わらず、ほぼ固定値と見なせる位相θで電流を分解するため、Iq、Idを成分とする電流検出ベクトルi1は、ｄ−ｑ軸上を電動機の実速度で回転するように検出される。これは、電動機の励磁インダクタンスに蓄えられているエネルギーが放電されるまで減衰しながら継続する。
このIq、Id用いて電流制御を行なうため、電圧指令値にも上記の過渡現象が発生し、電圧指令ベクトルｖ1は、ｄ−ｑ軸上を電動機の実速度で回転する。
この現象を用いて、ベクトル制御が成立している限り、起こり得ない状態を捉えることで、速度検出器１７の断線状態を検出することができる。
図２（ａ）〜（ｃ）は、速度検出器断線検出回路１８で行なう速度検出器の断線検出ブロック図である。なお、θｖ＝ｔａｎ^-1（Ｖｑ*／Ｖｄ*）とし、θｖは−１８０度から＋１８０度で演算されているものとしているが、 図２（ａ）、（ｂ）のθｖは、後述するθe＝ｔａｎ^-1（Ｅq／Ｅd）あるいはθｉ＝ｔａｎ^-1（Ｉｑ／Ｉｄ）とすることができる。
【００２３】
図２（ａ）は、θｖが一定時間内で所定値１以上変化したという条件を検出するものである。一定時間を制御周期として遅延回路２０を用いて、この制御周期での変化量の絶対値が所定値１を大きいがどうかで判別する。ここでは、一定時間を制御周期としたが制御周期と独立した値としてもよい。所定値１は、先に決めた一定時間で動くことができない移動量を、電動機等のイナーシャから求めて決める。なお、比較器は＋端子の入力値が−端子の入力値より大きいときに出力１を出し、このとき断線を検出するものとする。
【００２４】
図２（ｂ）は、θｖが所定値から外れた値となった条件を検出するものである。θｖが正常動作で取り得る値を±１１０度程度とすれば、所定値２を＋１１０度、所定値３を−１１０度と決める。
図２（ｃ）は、誘導電動機のように、滑りのある交流電動機の場合、過大スリップ状態でつり合い、電動機は暴走しない状態となる条件を捉えるものである。この条件は、速度制御器１１の出力値Iq*が大きくなり、滑り周波数指令値ωs*が実際値より大きくなるために生じる。式（１）、（２）でIqに大きな値を代入すると、Ｖｄ*＜０、Ｖｑ*＞０となるため、Ｖｄ*、Ｖｑ*の符号が異なる状態で検出するものである。
これまでθｖとしてｔａｎ^-1（Ｖｑ*／Ｖｄ*）を用いて説明したが、式（３）、（４）により、誘起電圧Ｅのｑ、ｄ軸成分をＥｑ、Ｅｄとして、θe＝ｔａｎ^-1（Ｅq／Ｅd）を演算し、θｖの替わりにθeを用いることができる。
【００２５】
Ｅｑ＝Ｖｑ*−（√３・ｒ１・Iq＋√３・ω₁*・ｌ・Id） …（３）
Ｅｄ＝Ｖｄ*−(√３・ｒ１・Id−√３・ω₁*・ｌ・Iq） …（４）
【００２６】
これは、ベクトル制御が成立している場合は、θｅ＝ｔａｎ-1（Ｅｑ／Ｅｄ）はｄ軸に対し９０度となる値であるので、この演算値を用いることで、更に検出精度を上げることができる。
また、上述したように、速度検出器の断線時は、電流検出値Ｉｄ、Ｉｑはｄ−ｑ軸上を電動機の実速度で回転するので、θｉ＝ｔａｎ^-1（Ｉｑ／Ｉｄ）を演算し、θｖの替わりにθｉを用いて、全く同様に断線検出できる。
なお、誤検出を極力避けるため、図２（ａ）〜（ｃ）の検出条件に速度検出値＝０をＡＮＤ条件で付加してもよいし、制御周期何回か継続して上記条件を満足したときに速度検出器の断線と判断させるようにしてもよい。なお＊は指令値であることを意味する。
【００２７】
【発明の効果】
以上述べたように、本発明の電動機制御装置によれば、電動機がゼロ速度付近で駆動されている場合でも、電動機の制御量を用いた簡単な演算により、速度検出器が断線しているのか否かを正確に判断でき、特にクレーンやエレベータのように垂直方向に動く機械の安全性を向上することができるという効果がある。
【図面の簡単な説明】
【図１】本発明の第１実施例を示す電動機制御装置のブロック図
【図２】本発明の実施例を示す速度検出器断線検出回路１８で行なう速度検出器の断線検出ブロック図
【符号の説明】
１ 電圧形ＰＷＭインバータ
２ 交流電動機
３ ベクトル制御装置
4-1、4-2、4-3 電流検出器
５ ｄ−ｑ変換器
６ 電圧指令演算器
7-1 トルク電流制御器
7-2 励磁電流制御器
８ 速度演算器
９ 磁束指令発生器
１０ 係数器
１１ 速度制御器
１２ 積分器
１３ 加算器
１４ 指令発生器
１５ 滑り周波数指令演算器
１６ 直流電源
１７ 速度検出器
１８ 速度検出器断線検出回路
２０ 遅延回路
２１ 減算器
２２ 絶対値回路
23-1、23-2、23-3、23-4 比較器
２４ OR回路
２５ 乗算器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor control device that detects disconnection of speed detection means such as a pulse encoder or resolver attached to the motor.
[0002]
[Prior art]
Conventionally, as a motor control device for detecting disconnection of a speed detector such as a pulse encoder attached to an electric motor, a pulse is generated when a state in which a change in an up / down counter connected to the pulse encoder is zero continues for a certain period of time. There is one that detects the disconnection of the encoder.
As hardware detection, for example, Japanese Laid-Open Utility Model No. 02-71273 has been proposed in which a special circuit is provided for detecting disconnection of a pulse encoder. However, the above-described prior art has a problem that it can be detected only when both of the two signal lines are disconnected, or a special circuit needs to be added to detect the disconnection. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 2001-249154, a unit of a counter that is up or down in the state of the other signal at the timing when one signal changes using two signals whose phases are 90 degrees different from each other. It has also been proposed to detect a disconnection of a pulse encoder that detects a disconnection of the pulse encoder when a state where the change per time is less than 2 continues for a certain time.
In addition, as a control device for an electric motor that performs detection using control information, for example, as in Japanese Patent Application No. 2002-221335 (filed on July 30, 2002) by the present applicant, a command torque component current is set.
[Expression 1]

[0004]
When the speed detector is not disconnected, adaptive control of induction motor parameters is performed using the difference between the two, and when the speed detector is disconnected, the difference between the two is proportional to the actual speed. A method for detecting disconnection of the speed detector by utilizing the change has been proposed. In addition,
[0005]
[Expression 2]

[0006]
Calculates the motor magnetic flux using the motor constant and calculates the outer product with the detected current.
[Equation 3]

[0008]
Seeking.
[0009]
[Patent Document 1]
Japanese Utility Model Publication No. 02-71273 [0010]
[Patent Document 2]
Japanese Patent Laid-Open No. 2001-249154
[Problems to be solved by the invention]
However, when the motor is driven near zero speed, which is near zero speed, the method of determining the disconnection of the speed detector based only on the speed detection value does not disconnect the state where the motor speed is zero. Since it occurs even in normal times, there was a possibility of false detection.
In addition, a motor control device that performs detection using control information has a complicated calculation process for obtaining an error signal for parameter adaptive control. In the case of a control device that does not have a margin for soft processing time, the calculation process cannot be incorporated. There was a problem that it could not be applied easily.
Therefore, the present invention has been made in view of such problems, and even when the electric motor is driven near zero speed, disconnection of a speed detector such as a pulse encoder attached to the electric motor can be reliably detected. An object of the present invention is to provide a motor control device that can be applied to a control device that does not use an expensive CPU by performing simple calculations using the control amount of the motor.
[0012]
[Means for Solving the Problems]
In order to solve the above problem, the present invention is configured as follows.
According to the first aspect of the present invention, the speed detecting means attached to the motor and the voltage and current of the motor are controlled by converting the coordinates of the two axes d and q to control the speed from the d or q component of the voltage or current. In the electric motor control device provided with the disconnection detection means for judging the disconnection of the detection means, the disconnection detection means of the speed detection means includes the excitation current direction voltage command value Vd *, the torque current direction voltage command as the values of the d and q components. Using the value Vq *, θv = tan−1 (Vq * / Vd *) is calculated, and when θv changes more than a predetermined value within a certain time, or θv becomes a value deviating from the predetermined value, It is determined that one of the disconnection conditions of the speed detection means is satisfied,
[0014]
The invention according to claim 2 calculates the induced voltage E as q and d-axis components as Eq and Ed as values of the d and q components, calculates θe = tan-1 (Eq / Ed), and θe is It is determined that one of the disconnection conditions of the speed detecting means is satisfied when the value changes by more than a predetermined value within a certain time or when θe becomes a value deviating from the predetermined value,
[0015]
In the third aspect of the present invention, the torque current feedback value Iq and the excitation current feedback value Id are used as the values of the d and q components, and θi = tan−1 (Iq / Id) is calculated. It is determined that one of the disconnection conditions of the speed detecting means is satisfied when θi changes beyond a predetermined value, or when θi becomes a value deviating from the predetermined value.
[0016]
According to the fourth aspect of the present invention, when the excitation current direction voltage command value Vd * and the torque current direction voltage command value Vq * are used as the d and q component values, the signs of Vd * and Vq * are different. and it is characterized in that it is determined that one of the disconnected condition of the speed detecting means is satisfied.
Thus, the disconnection of the speed detecting means can be determined from the d and q components of the motor voltage or current.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
As a control device for driving an AC motor, speed control using a variable voltage and variable frequency is known, and in order to perform more accurate control, a primary current supplied to the AC motor is converted into an excitation current (current that generates magnetic flux) and a torque current ( A vector control system that can achieve the same responsiveness as a DC / AC motor by controlling the secondary magnetic flux and torque current so that they are always orthogonal to each other. ing. Since the vector control method is well known, description thereof is omitted.
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an electric motor control device of the present invention. In the figure, a voltage source inverter 1 converts a DC voltage applied from a DC power supply 16 into an AC having an arbitrary frequency and voltage by a PWM control method. The AC motor 2 and a speed detector 17 as speed detecting means are connected to the AC output terminals of the phases U, V, and W of the voltage source inverter 1. The current flowing through each phase of the AC motor 2 is detected by current detectors 4-1 to 4-3 as current detection means.
[0018]
The vector control device 3 is provided with a dq converter 5 that detects a primary current of the AC motor 2 and performs coordinate conversion to send a torque current feedback value Iq and an excitation current feedback value Id. Furthermore, a speed controller (ASR) is provided so that the speed command value ωr * input from the command generator 14 and the speed detection value ωr from the speed calculator 8 that inputs the speed detector 17 and calculates the speed match. ) 11 is the torque current command value Iq *, and a torque current controller (ACRq) 7 for controlling the Iq * and the torque current feedback value Iq output from the dq converter 5 to coincide with each other. −1, in order to control the exciting current command value Id * calculated by the coefficient unit 10 using the output value of the magnetic flux command generator 9 as input, and the exciting current feedback value Id from the dq converter 5 to coincide with each other. Excitation current controller (ACRd) 7-2 is provided.
[0019]
A circuit that compensates for the induced voltage E generated in the AC motor 2, the voltage of the counter electromotive force due to the primary resistance r1 and the leakage inductance l is omitted. In the voltage command calculator 6, the sum of the output of the torque current controller 7-1, the excitation current controller 7-2, and the voltage compensation value of each back electromotive force is coordinate-converted by the phase θ of the integrator 12 output. Then, the voltage command value for each phase of U, V, and W is calculated and becomes a voltage command vector v1.
The slip frequency command calculator 15 obtains the slip frequency command value ωs * from the magnetic flux command generator 9 output φ *, the torque current command value Iq * and the set secondary resistance r2 (not shown), and adds the adder. 13 is added to the speed detection value ωr from the speed calculator 8 to calculate the primary frequency command value ω ₁ *, and the phase θ is calculated via the integrator 12.
[0020]
The speed detector disconnection detection circuit 18 includes a voltage command v1 (hereinafter abbreviated as v1 and a vector) having a torque current direction voltage command value Vq * and an excitation current direction voltage command value Vd * as components, and a torque current feedback value. A current detection vector i1 (hereinafter abbreviated as i1), which has Iq and excitation current feedback value Id as components, is used as an input value to determine whether the speed detector is disconnected. This detection method will be described later.
When the vector control is established, the torque current direction voltage command value Vq * and the torque current direction voltage actual value Vq, the excitation current direction voltage command value Vd * and the excitation current direction voltage actual value Vd match. , The first expression and the second expression are established.
[0021]
Vq * = E + √3 · r1 · Iq + √3 · ω ₁ * · l · Id + ACRq (1)
Vd * = √3 · r1 · Id−√3 · ω ₁ * · l · Iq + ACRd (2)
ACRq and ACRd indicate output values of the torque current controller 7-1 and the excitation current controller 7-2, respectively.
[0022]
However, when the speed detector 17 is in a disconnected state and the actual speed is ωr but the output of the speed calculator 8 becomes 0, the rotating magnetic field is generated in the motor, but the value is almost fixed. In order to decompose the current with a phase θ that can be considered, the current detection vector i1 having Iq and Id as components is detected so as to rotate on the dq axis at the actual speed of the motor. This continues while decaying until the energy stored in the magnetizing inductance of the motor is discharged.
Since current control is performed using these Iq and Id, the above transient phenomenon also occurs in the voltage command value, and the voltage command vector v1 rotates on the dq axis at the actual speed of the motor.
Using this phenomenon, it is possible to detect the disconnection state of the speed detector 17 by capturing a state that cannot occur as long as the vector control is established.
FIGS. 2A to 2C are block diagrams of a speed detector disconnection detection performed by the speed detector disconnection detection circuit 18. Note that θv = tan ⁻¹ (Vq * / Vd *) and θv is calculated from −180 degrees to +180 degrees. However, θv in FIGS. 2A and 2B is θe described later. = Tan ⁻¹ (Eq / Ed) or θi = tan ⁻¹ (Iq / Id).
[0023]
FIG. 2A detects the condition that θv has changed by a predetermined value 1 or more within a certain time. Using the delay circuit 20 with a fixed time as the control period, it is determined whether or not the absolute value of the change amount in the control period is larger than the predetermined value 1. Here, the fixed period is the control period, but it may be a value independent of the control period. The predetermined value 1 is determined by obtaining the amount of movement that cannot move in the predetermined time determined from the inertia of the electric motor or the like. The comparator outputs 1 when the input value at the + terminal is larger than the input value at the-terminal, and at this time, the disconnection is detected.
[0024]
FIG. 2B detects a condition in which θv becomes a value deviating from a predetermined value. If the value that θv can take in normal operation is about ± 110 degrees, the predetermined value 2 is determined to be +110 degrees and the predetermined value 3 is determined to be −110 degrees.
FIG. 2C shows a condition where an AC motor with slip, such as an induction motor, balances in an excessive slip state and the motor does not run away. This condition occurs because the output value Iq * of the speed controller 11 becomes large and the slip frequency command value ωs * becomes larger than the actual value. If a large value is substituted for Iq in equations (1) and (2), Vd * <0 and Vq *> 0 are obtained, and therefore detection is performed in a state where the signs of Vd * and Vq * are different.
So far, tan ⁻¹ (Vq * / Vd *) has been described as θv. However, according to the equations (3) and (4), qe and d-axis components of the induced voltage E are Eq and Ed, and θe = tan ^{− 1} (Eq / Ed) can be calculated, and θe can be used instead of θv.
[0025]
Eq = Vq * − (√3 · r1 · Iq + √3 · ω ₁ * · l · Id) (3)
Ed = Vd * − (√3 · r1 · Id−√3 · ω ₁ * · l · Iq) (4)
[0026]
This is because when vector control is established, θe = tan −1 (Eq / Ed) is a value that is 90 degrees with respect to the d-axis. be able to.
As described above, when disconnection of the speed detector, the current detection value Id, since Iq rotates the d-q-axis real speed of the motor, .theta.i = tan ^-1 a (Iq / Id) is calculated By using θi instead of θv, disconnection can be detected in exactly the same manner.
In order to avoid erroneous detection as much as possible, the speed detection value = 0 may be added to the detection conditions of FIGS. 2A to 2C as an AND condition, or the control condition is satisfied several times continuously. It may be determined that the speed detector is disconnected. Note that * means a command value.
[0027]
【The invention's effect】
As described above, according to the motor control device of the present invention, whether the speed detector is disconnected by a simple calculation using the control amount of the motor even when the motor is driven near zero speed. It is possible to accurately determine whether or not, and in particular, it is possible to improve the safety of a machine that moves in a vertical direction such as a crane or an elevator.
[Brief description of the drawings]
FIG. 1 is a block diagram of an electric motor control apparatus showing a first embodiment of the present invention. FIG. 2 is a block diagram of a speed detector disconnection detection performed by a speed detector disconnection detection circuit 18 according to an embodiment of the present invention. Explanation】
DESCRIPTION OF SYMBOLS 1 Voltage type PWM inverter 2 AC motor 3 Vector controller
4-1, 4-2, 4-3 Current detector 5 dq converter 6 Voltage command calculator
7-1 Torque current controller
7-2 Excitation current controller 8 Speed calculator 9 Magnetic flux command generator 10 Coefficient unit 11 Speed controller 12 Integrator 13 Adder 14 Command generator 15 Slip frequency command calculator 16 DC power supply 17 Speed detector 18 Speed detector Disconnection detection circuit 20 Delay circuit 21 Subtractor 22 Absolute value circuit
23-1, 23-2, 23-3, 23-4 Comparator 24 OR circuit 25 Multiplier

Claims (4)

Speed detection means attached to the motor, and disconnection detection means for determining the disconnection of the speed detection means from the d or q components of the voltage or current by converting the voltage and current of the motor into two axes d and q. In the provided motor control device,
The disconnection detecting means of the speed detecting means uses the excitation current direction voltage command value Vd * and the torque current direction voltage command value Vq * as the values of the d and q components , and θv = tan−1 (Vq * / Vd *) When θv changes by more than a predetermined value within a predetermined time, or when θv becomes a value deviating from the predetermined value, it is determined that one of the disconnection conditions of the speed detecting means is satisfied. Electric motor control device. Speed detection means attached to the motor, and disconnection detection means for determining the disconnection of the speed detection means from the d or q components of the voltage or current by converting the voltage and current of the motor into two axes d and q. In the provided motor control device,
The disconnection detection means of the speed detection means calculates q and d-axis components of the induced voltage E as Eq and Ed as values of the d and q components, calculates θe = tan-1 (Eq / Ed), and θe The motor control device is characterized in that one of the disconnection conditions of the speed detecting means is satisfied when the value changes by more than a predetermined value within a predetermined time or when θe becomes a value deviating from the predetermined value. Speed detection means attached to the motor, and disconnection detection means for determining the disconnection of the speed detection means from the d or q components of the voltage or current by converting the voltage and current of the motor into two axes d and q. In the provided motor control device,
The disconnection detecting means of the speed detecting means calculates θi = tan−1 (Iq / Id) using the torque current feedback value Iq and the excitation current feedback value Id as the values of the d and q components, and θi is constant time. An electric motor control device characterized by determining that one of the disconnection conditions of the speed detecting means is satisfied when the value changes within a predetermined value or when θi becomes a value deviating from the predetermined value. Speed detection means attached to the motor, and disconnection detection means for determining the disconnection of the speed detection means from the d or q components of the voltage or current by converting the voltage and current of the motor into two axes d and q. In the provided motor control device,
The disconnection detection means of the speed detection means uses the excitation current direction voltage command value Vd * and the torque current direction voltage command value Vq * as the values of the d and q components, and the signs of Vd * and Vq * are different. In addition, it is determined that one of the disconnection conditions of the speed detecting means is satisfied.

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