JPH06292385A - Digital current control method for induction motor - Google Patents
Digital current control method for induction motorInfo
- Publication number
- JPH06292385A JPH06292385A JP5077979A JP7797993A JPH06292385A JP H06292385 A JPH06292385 A JP H06292385A JP 5077979 A JP5077979 A JP 5077979A JP 7797993 A JP7797993 A JP 7797993A JP H06292385 A JPH06292385 A JP H06292385A
- Authority
- JP
- Japan
- Prior art keywords
- current
- values
- digital
- value
- current value
- 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.)
- Pending
Links
Landscapes
- Control Of Electric Motors In General (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は電流検出遅れを補償でき
る、誘導電動機のディジタル電流制御方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital current control method for an induction motor capable of compensating for current detection delay.
【0002】[0002]
【従来の技術】従来のディジタル電流制御方法では、誘
導電動機の各相(u,v,w)の電流を検出し、ディジ
タル値に変換し、そのディジタル値と各相電流指令値と
の偏差を検出し、ゲイン(定数)を乗じ、電圧出力変換
器により、各相電圧指令値としてPWM回路に出力し
て、各相の電流が電流指令値どおりになるように制御し
ている。2. Description of the Related Art In a conventional digital current control method, the current of each phase (u, v, w) of an induction motor is detected and converted into a digital value, and the deviation between the digital value and each phase current command value is calculated. It is detected, multiplied by a gain (constant), and output to the PWM circuit as a voltage command value for each phase by the voltage output converter, and the current of each phase is controlled to be the same as the current command value.
【0003】[0003]
【発明が解決しようとする課題】上記の方法にあって
は、各相の電流検出時刻と各相電圧指令出力時刻との時
間差を考慮していない。電圧指令出力時には、電流は電
流検出時刻の値より変化しているはずである。従来の方
法は、時間差(遅れ)を考慮して電圧指令値を算出して
いないので、ゲイン(定数)を大きく取ると、制御系が
不安定になりその結果制御不能になってしまう。また、
制御系が不安定になる限界まで、ゲイン(定数)を大き
くしても、電流の追随性が悪く、結果として正規のトル
クが出力されないという問題がある。In the above method, the time difference between the current detection time of each phase and the voltage command output time of each phase is not taken into consideration. At the time of voltage command output, the current should have changed from the value at the current detection time. Since the conventional method does not calculate the voltage command value in consideration of the time difference (delay), if the gain (constant) is large, the control system becomes unstable, and as a result, the control becomes impossible. Also,
Even if the gain (constant) is increased up to the limit where the control system becomes unstable, there is a problem in that the followability of the current is poor and, as a result, the normal torque is not output.
【0004】本発明は上記問題に鑑み、前記時間差を減
少させて安定に制御できるディジタル電流制御方法を提
供することを目的とする。In view of the above problems, it is an object of the present invention to provide a digital current control method capable of reducing the time difference and performing stable control.
【0005】[0005]
【課題を解決するための手段】本発明のディジタル電流
制御方法は、すべり周波数ベクトル制御装置から与えら
れるディジタル電流指令値と、PWM回路に制御されて
誘導電動機に流される電流を示すディジタル電流値との
偏差を各サンプリングタイミング毎に算出し、算出した
偏差に基づく電圧指令値でPWM回路に指示を行なうデ
ィジタル電流制御方法であって、現在の前記ディジタル
電流値と過去の前記ディジタル電流値との間の偏差に定
数を乗じたものと、現在のディジタル電流値とを加算
し、その結果を予測電流値とし、前記ディジタル電流指
令値と前記ディジタル電流値との偏差を算出するに際
し、ディジタル電流値の代わりに予測電流値を用いる。A digital current control method according to the present invention includes a digital current command value provided from a slip frequency vector control device and a digital current value indicating a current supplied to an induction motor under the control of a PWM circuit. Is a digital current control method for calculating a deviation of each sampling timing and instructing a PWM circuit with a voltage command value based on the calculated deviation. When the deviation is multiplied by a constant and the current digital current value is added, and the result is used as the predicted current value, the deviation between the digital current command value and the digital current value is calculated. The predicted current value is used instead.
【0006】好ましくは、前記過去のディジタル電流値
として、1サンプリングタイミング前のディジタル電流
値を用い、前記定数は0以上1以下とする。Preferably, a digital current value one sampling timing before is used as the past digital current value, and the constant is 0 or more and 1 or less.
【0007】[0007]
【作用】このように構成したディジタル電流制御装置に
おいて、u,v,w各相の電流が読み込まれ、ディジタ
ル値に変換される。現時点で得られた電流検出値と1サ
ンプリングタイミングだけ過去の電流検出値の変化分に
適当な定数(0≦kx ≦1)を乗じ、現時点で得られた
電流検出値に加える。この値を電流予測値として偏差を
求め、u,v,w各相の電圧出力値を演算し、PWM回
路に出力することにより、時間遅れは減少され各相の電
流が指令値に一致するようになる。In the digital current controller thus constructed, the currents of the u, v and w phases are read and converted into digital values. The current detection value obtained at the present time and the change amount of the current detection value in the past by one sampling timing are multiplied by an appropriate constant (0 ≦ k x ≦ 1) and added to the current detection value obtained at the present time. This value is used as a current prediction value to obtain the deviation, calculate the voltage output value of each phase of u, v, w and output it to the PWM circuit so that the time delay is reduced and the current of each phase matches the command value. become.
【0008】[0008]
【実施例】次に、本発明の実施例について図面を参照し
て説明する。図1は本発明のディジタル電流制御装置の
一実施例を示すブロック図、図2は図1の実施例の動作
を示すグラフである。すべり周波数ベクトル制御装置1
(以降、ベクトル制御装置1と略記する)は、トルク指
令および位置検出器10により検出された誘導電動機9
の回転子の位置データにより、u,v,w各相のディジ
タル電流指令値を出力する。Embodiments of the present invention will now be described with reference to the drawings. 1 is a block diagram showing an embodiment of the digital current control device of the present invention, and FIG. 2 is a graph showing the operation of the embodiment of FIG. Slip frequency vector control device 1
(Hereinafter, abbreviated as the vector control device 1) is the induction motor 9 detected by the torque command and the position detector 10.
The digital current command value for each phase of u, v, and w is output according to the rotor position data of.
【0009】誘導電動機9の各相の電流値は電流センサ
8により検出され、電流制御部の電流検出器7に入力さ
れ、アナログ値からディジタル値に変換される。電流予
測器6は、電流検出器7から与えられた電流検出値に基
づき、電流予測値を算出する。ここで、電流予測値の算
出について図2を参照して説明する。現時点、すなわち
時刻tn における電流値をi(n)とし、1ステップ以
前すなわち、時刻tn-1 の電流値をi(n−1)、プロ
グラム上あるいは実験結果から適宜選択される定数kx
(0≦kx ≦1)、kx に依存し時刻tn において、回
路等の遅れにより、実際に指令が実行される時刻t′に
おける電流値として予測される予測電流値をi* (n)
とすると、予測電流値i* (n)は下記の式(1)によ
り求めることができる。The current value of each phase of the induction motor 9 is detected by the current sensor 8 and input to the current detector 7 of the current control section, where it is converted from an analog value to a digital value. The current predictor 6 calculates the predicted current value based on the detected current value supplied from the current detector 7. Here, the calculation of the predicted current value will be described with reference to FIG. Currently, that is, the current value at time t n and i (n), 1 step previously i.e., the time t n-1 of a current value i (n-1), the constant k x is suitably selected from a program or on experimental results
(0 ≦ k x ≦ 1) , at time t n depends on k x, the delay of the circuit or the like, actually predicted current values is predicted as a current value at time t 'which command is executed i * (n )
Then, the predicted current value i * (n) can be obtained by the following equation (1).
【0010】 i* (n)=i(n)+kx ・(i(n)−i(n−1))・・・(1) すなわち、回路等の時間遅れをkx で吸収し、時刻tn
における電流値i(n)として、電流予測値i* (n)
を与えることにより、正確な制御をしようとするもので
ある。[0010] i * (n) = i ( n) + k x · (i (n) -i (n-1)) ··· (1) In other words, to absorb the time delay of the circuit and the like in the k x, time t n
As the current value i (n) at, the predicted current value i * (n)
By giving, the precise control is intended.
【0011】偏差演算器2は、u,v,w相電流指令値
と電流予測値との偏差を求める。乗算器3は、偏差演算
器2によって求められた偏差と、与えられたゲインKと
の乗算を行う。電圧出力変換器4は、乗算の結果に基づ
いて、PWM回路5にu,v,w相電圧指令値を出力
し、PWM回路5の出力電流の偏差が打消されるように
u,v,w各相の電流を制御する。The deviation calculator 2 calculates the deviation between the u, v, and w phase current command values and the predicted current value. The multiplier 3 multiplies the deviation calculated by the deviation calculator 2 by the given gain K. The voltage output converter 4 outputs u, v, w phase voltage command values to the PWM circuit 5 based on the result of the multiplication so that the deviation of the output current of the PWM circuit 5 is canceled. Control the current of each phase.
【0012】[0012]
【発明の効果】以上説明したように本発明は、ディジタ
ル電流制御において用いられている電流検出値を、演算
時間のおくれを考慮した予測電流値にすることにより、
制御系のゲイン(定数)を大きく取れるようになり、そ
の結果指令値に検出値がよく一致する効果が生ずる。As described above, according to the present invention, the current detection value used in the digital current control is set to the predicted current value in consideration of the delay of the calculation time.
The gain (constant) of the control system can be made large, resulting in the effect that the detected value is in good agreement with the command value.
【図1】本発明のディジタル電流制御方法の一実施例が
適用されたディジタル電流制御装置を示すブロック図で
ある。FIG. 1 is a block diagram showing a digital current control device to which an embodiment of a digital current control method of the present invention is applied.
【図2】図1の装置の動作を示すグラフである。FIG. 2 is a graph showing the operation of the apparatus of FIG.
1 すべり周波数ベクトル制御装置 2 偏差演算器 3 ゲイン(定数) 4 電圧出力変換器 5 PWM回路 6 電流予測器 7 電流検出器 8 電流センサ 9 誘導電動機 10 位置検出器 Δt サンプリング時間 1 Slip frequency vector control device 2 Deviation calculator 3 Gain (constant) 4 Voltage output converter 5 PWM circuit 6 Current predictor 7 Current detector 8 Current sensor 9 Induction motor 10 Position detector Δt Sampling time
Claims (2)
られるディジタル電流指令値と、PWM回路に制御され
て誘導電動機に流される電流を示すディジタル電流値と
の偏差を各サンプリングタイミング毎に算出し、算出し
た偏差に基づく電圧指令値でPWM回路に指示を行なう
ディジタル電流制御方法において、 現在の前記ディジタル電流値と過去の前記ディジタル電
流値との間の偏差に定数を乗じたものと、現在のディジ
タル電流値とを加算し、その結果を予測電流値とし、前
記ディジタル電流指令値と前記ディジタル電流値との偏
差を算出するに際し、ディジタル電流値の代わりに予測
電流値を用いることを特徴とするディジタル電流制御方
法。1. A deviation between a digital current command value given from a slip frequency vector control device and a digital current value showing a current flowing through an induction motor under the control of a PWM circuit is calculated at each sampling timing and calculated. In a digital current control method for instructing a PWM circuit with a voltage command value based on a deviation, a deviation between a current digital current value and a past digital current value multiplied by a constant and a current digital current value Is added, and the result is used as a predicted current value, and when the deviation between the digital current command value and the digital current value is calculated, the predicted current value is used instead of the digital current value. Method.
サンプリングタイミング前のディジタル電流値を用い、
前記定数は0以上1以下である請求項1記載のディジタ
ル電流制御方法。2. The past digital current value is 1
Using the digital current value before the sampling timing,
The digital current control method according to claim 1, wherein the constant is 0 or more and 1 or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5077979A JPH06292385A (en) | 1993-04-05 | 1993-04-05 | Digital current control method for induction motor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5077979A JPH06292385A (en) | 1993-04-05 | 1993-04-05 | Digital current control method for induction motor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH06292385A true JPH06292385A (en) | 1994-10-18 |
Family
ID=13649011
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5077979A Pending JPH06292385A (en) | 1993-04-05 | 1993-04-05 | Digital current control method for induction motor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH06292385A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005312274A (en) * | 2004-04-26 | 2005-11-04 | Mitsubishi Electric Corp | Control device for ac motor |
JP2009077513A (en) * | 2007-09-20 | 2009-04-09 | Meidensha Corp | Method for detecting output current in voltage-type pwm inverter device |
JP2014073029A (en) * | 2012-09-28 | 2014-04-21 | Fuji Electric Co Ltd | Device for controlling ac motor |
JP2021141629A (en) * | 2020-03-02 | 2021-09-16 | 三菱電機株式会社 | Control apparatus for ac rotary electric machine |
-
1993
- 1993-04-05 JP JP5077979A patent/JPH06292385A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005312274A (en) * | 2004-04-26 | 2005-11-04 | Mitsubishi Electric Corp | Control device for ac motor |
JP2009077513A (en) * | 2007-09-20 | 2009-04-09 | Meidensha Corp | Method for detecting output current in voltage-type pwm inverter device |
JP2014073029A (en) * | 2012-09-28 | 2014-04-21 | Fuji Electric Co Ltd | Device for controlling ac motor |
JP2021141629A (en) * | 2020-03-02 | 2021-09-16 | 三菱電機株式会社 | Control apparatus for ac rotary electric machine |
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