JP2016019461A - Phase generation device for induction motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase generation device which does not require rotor speed information at all, in particular, to provide a phase generation device which stably operates in both power-running and regenerative drive mode, the phase generation device being used for a drive control device for an induction motor and including at least means for generating a speed and a phase of a γδ quasi-synchronous coordinate system.SOLUTION: The speed and phase generation means generates the coordinate system speed by using γ-axis elements of a value corresponding to a driving voltage, a value corresponding to a driving current and a value corresponding to a stator magnetic flux, stator resistance, total stator leakage inductance, a code function and a positive gain and generates the phase by performing integration processing on the generated coordinate system speed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a phase generator used in a drive control device for an induction motor. In particular, the present invention relates to a phase generation device that generates a phase of a rotor magnetic flux by using a voltage / current for driving an electric motor. In the description of the present invention, “phase” is used synonymously with “angular position” and “velocity” is used synonymously with “angular velocity”. Further, “stator” and “rotor” of the induction motor are used synonymously with “primary side” and “secondary side”, respectively.

  In FIG. 1, three coordinate systems are drawn: a γδ general coordinate system, an αβ fixed coordinate system, and a dq synchronous coordinate system. The α axis, which is the basic axis of the αβ fixed coordinate system, is an axis in the same direction as the u-phase winding center of the stator. The d-axis, which is the base axis of the dq synchronous coordinate system, is an axis in the same direction as the rotor magnetic flux or the proportional value (represented as φ2n in the figure) as a 2 × 1 vector (abbreviated as 2 × 1) vector. . The γδ general coordinate system is a general coordinate system including the αβ fixed coordinate system and the dq synchronous coordinate system as special cases. In the present invention, among the γδ general coordinate system, a coordinate system aiming at convergence without phase difference to the dq synchronous coordinate system is called a γδ quasi-synchronous coordinate system.

  As a typical vector control method for an induction motor, there is a slip frequency type vector control method. This method is also the simplest way to achieve ideal vector control. In the slip frequency vector control method, the frequency generated by adding the estimated slip frequency to the rotor speed is the speed of the γδ quasi-synchronous coordinate system, and hence the frequency of the voltage applied to the stator (ie, the power supply frequency). It is. In the slip frequency vector control method, “rotor speed is available” is an essential requirement for realizing this method. For this reason, a speed detector such as an incremental encoder has been widely used in performing slip frequency vector control.

  However, the mounting of the speed detector to the rotor caused various problems such as a decrease in electrical / mechanical / thermal reliability, an increase in axial volume, wiring of the detector, and an increase in cost. . Depending on the application, it may be difficult or impossible to mount the speed detector. Conventionally, various sensorless vector control methods have been researched and developed as a technique for overcoming this problem. In the sensorless vector control method, basically, a speed estimator is configured by software inside the operator instead of installing the speed detector, and the speed estimated value is used instead of the speed detected value (speed true value). Thus, vector control is performed.

  In accordance with the above idea, for the slip frequency vector control method using the sensor (that is, using the speed detector), it is possible to remove the speed detector and configure a new speed estimator to achieve sensorlessness. Various attempts have been made. Patent Documents 1 and 2 are examples of this, and a power frequency is determined by adding a slip frequency estimated value to a speed estimated value. The realization of the sensor-based slip frequency vector control method was extremely simple. However, this sensorless operation requires a complicated speed estimation unit as shown in the examples of Patent Documents 1 and 2, and as a result, the sensorless slip frequency vector control method is the most complicated sensorless vector control method. It became one.

  As a method to fundamentally solve the problem of “necessity of complicated speed estimation unit” that sensorless slip frequency vector control method inevitably has, sensorless vector control method that does not require any speed information is This is proposed through Patent Document 3. The method of Patent Document 3 does not require any rotor information to perform vector control. As a result, this method is as simple as the power-based frequency (γδ quasi-synchronous coordinate system of the sensor-based slip frequency vector control method). (Equivalent to velocity ωγ). FIG. 4 is a block diagram (coordinate system speed estimator) showing a method of generating the power supply frequency (speed γγ of the γδ quasi-synchronous coordinate system) proposed in Patent Document 3. However, when the power supply frequency generated by the method of Patent Document 3 is used, the regenerative induction motor drive control system may become unstable.

Masato Mori and Masamasa Ashikaga: “Speed vector control method of induction motor”, Japanese Patent Laid-Open No. 7-123799 (1993-10-25) Masato Mori, Masamasa Ashikaga, Katsuyuki Watanabe: “Secondary resistance compensation method for induction motors”, Japanese Patent Laid-Open No. 7-303398 (1994-5-9) Shinnaka Shinji: “Vector control method and apparatus for induction motor”, Japanese Patent Laid-Open No. 10-80200 (1996-8-30)

  The present invention has been made under the above background, and its object is to be used in a drive control device for an induction motor, which does not require speed information to perform vector control, and is simple, An object of the present invention is to provide a phase generation device that operates stably in both regenerative drive modes. The phase generated by the phase generation device is a phase of a γδ quasi-synchronous coordinate system aimed at convergence to a dq synchronous coordinate system in which the phase of the rotor magnetic flux is the d-axis phase. This means that “the generation phase is a phase estimation value of the rotor magnetic flux”. As is obvious to those skilled in the art, the differential value of the phase of the γδ quasi-synchronous coordinate system is the speed of the coordinate system, and at the same time, the frequency of the voltage current applied to the induction machine (power supply frequency). The phase and speed of the γδ quasi-synchronous coordinate system are strictly calculus, and one can be obtained from the other.

γδ準同期座標系の速度ωγを、正ゲインｇ３をもつ次の生成基本式に準拠して生成し、

生成した座標系速度ωγを積分処理してγδ準同期座標系の位相を生成するようにしたことを特徴とする。（２）式に利用された符号関数（シグナム関数とも呼ばれる）ｓｇｎの働きは、（１）式が明瞭に示しているように、対象信号の極性（すなわち、プラス、マイナス）を抽出することである。In order to achieve the above object, the invention of claim 1 is used in a drive control device for an induction motor, and aims at convergence to a dq synchronous coordinate system in which the phase of the rotor magnetic flux is the phase of the d axis. A phase generation device comprising at least a means for generating a speed and a phase of a γδ quasi-synchronous coordinate system using an equivalent value of a driving voltage and a corresponding value of a driving current on a quasi-synchronous coordinate system as input signals, The voltage equivalent value γ-axis element and δ-axis element are v1γ and v1δ, respectively, the drive current equivalent value γ-axis element and δ-axis element are i1γ and i1δ, respectively, and the stator flux equivalent value γ-axis element is φ. When 場合 1γ, the stator resistance is R1, the stator total leakage inductance is l1t, s is the differential operator d / dt, and the sign function sgn is defined as follows:

A speed ωγ of the γδ quasi-synchronous coordinate system is generated according to the following generation basic formula having a positive gain g3,

The generated coordinate system velocity ωγ is integrated to generate the phase of the γδ quasi-synchronous coordinate system. The function of the sign function (also referred to as a signum function) sgn used in equation (2) is to extract the polarity (ie, plus or minus) of the target signal as clearly shown in equation (1). is there.

  A second aspect of the present invention is the phase generation apparatus according to the first aspect, wherein a signal obtained by additionally subjecting a signal generated in accordance with the generation basic expression to a change rate limiting process is represented by a γδ quasi-synchronous coordinate system. It is characterized by the final speed of the system.

  A third aspect of the invention is the phase generation device according to the first aspect, wherein the signal corresponding to the denominator and numerator of the generation basic expression (ie, the expression (2)) is individually filtered, The signal is divided in accordance with the generation basic formula to generate a γδ quasi-synchronous coordinate system speed ωγ.

  The term “equivalent value” used above means a true value of the signal, a good approximate value of the true value, an estimated value, or a signal having a good correlation with the true value.

Hereinafter, the effects of the present invention will be described clearly with reference to the drawings and mathematical expressions. Consider a γδ general coordinate system rotating at an arbitrary speed ωγ as shown in FIG. Further, it is assumed that the rotor magnetic flux of the induction motor has a phase θγ instantaneously with respect to the main axis γ-axis. A mathematical model (circuit equation) of the induction motor on the γδ general coordinate system is described by the following equations (3) to (4).

  In the equations (3) to (4), 2 × 1 vectors v1 and i1 represent the stator voltage and current, respectively, and φ2 represents the rotor magnetic flux. ω2n is the electrical speed of the rotor, and s is the differential operator d / dt. R1, l1t, M, L2, and W2 indicate motor parameters, and are respectively the stator resistance, the stator total leakage inductance, the mutual inductance, the rotor inductance, and the reciprocal of the rotor time constant (hereinafter referred to as the rotor reverse). Means constant).

上式より明白なように、正規化回転子磁束は回転子磁束の比例値である。同様に、回転子抵抗Ｒ２の比例値として、正規化回転子抵抗Ｒ２ｎを以下のように定義する。

Here, the normalized rotor magnetic flux φ2n is defined as follows as one of the values corresponding to the rotor magnetic flux.

As is clear from the above equation, the normalized rotor magnetic flux is a proportional value of the rotor magnetic flux. Similarly, the normalized rotor resistance R2n is defined as follows as a proportional value of the rotor resistance R2.

The circuit equation (3) can be rewritten as the following equation using equations (5) and (6).

スカラ信号の脚符γ、δは、対応信号のγ軸要素、δ軸要素を意味している。Expression (7) can be revised to an expression using elements of vector signals. One example of this is:

The symbols γ and δ of the scalar signal mean the γ-axis element and the δ-axis element of the corresponding signal.

（９ｃ）式は、（９ａ）式、（９ｂ）式に用いた固定子磁束相当値のγ軸要素φ＾１γの基本定義式を示している。Equation (8a) is rewritten as follows regarding the δ-axis element φ2nδ of the normalized rotor magnetic flux.

Equation (9c) shows the basic definition equation of the γ-axis element φ ^ 1γ of the stator magnetic flux equivalent value used in equations (9a) and (9b).

（１０）式におけるωγとして、請求項１の発明に従って生成されたωγを適用すると、すなわち（２）式のωγを適用すると、次式を得る。

From the equation (9), the following equation using a positive gain g3 can be obtained.

When ωγ generated according to the invention of claim 1 is applied as ωγ in equation (10), that is, when ωγ in equation (2) is applied, the following equation is obtained.

  The above equation means that the δ-axis element of the normalized rotor magnetic flux converges to zero. In other words, the γδ general coordinate system means a γδ quasi-synchronous coordinate system. Formula (11) can be established regardless of the powering / regenerative drive mode. It should be noted that the basic property of vector control of “controlling the excitation current i1γ constant” is used for approximation of the expression (2) from the first expression to the second expression. Under this control, the γ-axis element of the stator magnetic flux equivalent value shown in equation (9c) is constant, and this differential value is zero.

  As is clear from the analysis results described above, according to the invention of claim 1, γδ quasi-synchronization can be stably performed in both the power running and regenerative drive modes without requiring any rotor speed information. An effect is obtained that the phase of the coordinate system (the integral value of the coordinate system velocity) can be generated. The phase of the γδ quasi-synchronous coordinate system is also an estimated value of the rotor magnetic flux phase. Therefore, this effect can be paraphrased as an effect that it is possible to generate an estimated value of the rotor magnetic flux phase in both the power running and regenerative drive modes without requiring any rotor speed information. .

  Next, the effect of the invention of claim 2 will be described. When generating the coordinate system phase through the speed ωγ of the γδ quasi-synchronous coordinate system and this integration process according to the expression (2) which is the invention of claim 1, motor parameters are required. However, in an actual drive system, the parameter true value cannot always be known, and a nominal parameter having an error must be used. An AC voltage is applied to the induction motor via a power converter, but the power converter does not always have ideal characteristics. Similarly, current detectors do not always have ideal characteristics. That is, the voltage equivalent value and the current equivalent value in the equation (2) are accompanied by various errors as in the motor parameter. As a result, in an actual drive system, various errors are mixed in the speed ωγ of the γδ quasi-synchronous coordinate system generated by the equation (2). As a result, the coordinate system velocity generated according to the equation (2) accompanied by the differentiation process may take an undesirably excessive value.

  According to the second aspect of the present invention, the final velocity of the γδ quasi-synchronous coordinate system is obtained as a signal obtained by additionally subjecting the signal generated in accordance with the generation basic equation, that is, the signal generated in accordance with the equation (2) Will be. As a result, the coordinate system speed can be prevented from taking an unnecessary excessive value. That is, according to the second aspect of the present invention, it is possible to prevent the coordinate system speed from taking an unnecessary excessive value even when the motor parameter, the voltage equivalent value, and the current equivalent value are not ideal. can get. As a result, the effect that the effect of Claim 1 can be heightened practically is acquired.

  Next, the effect of the invention of claim 3 will be described. In the explanation of the effect of the invention of claim 2, as explained, various errors are mixed in the speed ωγ of the γδ quasi-synchronous coordinate system generated by the equation (2). For this reason, the coordinate system velocity generated according to the equation (2) may take an undesirably excessive value. The biggest cause of the occurrence of the excessive value is the differentiation process in the equation (2). According to the third aspect of the present invention, the signal corresponding to the denominator and the numerator of the generation basic expression, that is, the expression (2) is individually filtered, and the filtered signal is divided in accordance with the generation basic expression. , Γδ quasi-synchronous coordinate system speed ωγ is generated. The filter at this time is basically a low-pass filter. Direct differentiation can be avoided by the low-pass filter effect. As a result, the coordinate system speed obtained by dividing the signal after filtering does not take an excessive value. As can be seen from the above, according to the third aspect of the present invention, it is possible to prevent the coordinate system speed from taking an unnecessary excessive value even when the motor parameter, the voltage equivalent value, and the current equivalent value are not ideal. You can get the effect that you can. As a result, the effect that the effect of Claim 1 can be heightened practically is acquired.

  The figure which shows the example of 1 relationship of three types of coordinate systems and a rotor magnetic flux phase   Block diagram showing an example of a drive control system using a rotor magnetic flux estimator on a γδ quasi-synchronous coordinate system according to the present invention   The block diagram which shows the internal structural example of the rotor magnetic flux estimator on (gamma) delta semi-synchronous coordinate system based on this invention   Block diagram showing an internal configuration example of a conventional coordinate system speed estimator

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 shows an embodiment in which a drive control device using the phase generator of the present invention is applied to an induction motor. The main point of the present invention is a phase generator (hereinafter also referred to as a rotor magnetic flux estimator). However, in order to clarify the position of the phase generator (rotor magnetic flux estimator) in the entire motor drive control system, the drive control is intentionally performed. The entire motor drive control system including the apparatus will be described. 1 is an induction motor, 2 is a power converter, 3 is a current detector, 4a and 4b are 3-phase 2-phase converters, 2-phase 3-phase converters, 5a and 5b are both vector rotators, Reference numeral 6 denotes a current controller, 7 denotes a rotor magnetic flux estimator (phase generator) using the present invention, 8 denotes a magnetic flux controller, and 9 denotes a command converter. As will be easily understood by those skilled in the art, in FIG. 2, various devices from 2 to 9 except for one electric motor constitute a drive control device. The rotor magnetic flux estimator directly related to the present invention is also used in torque control and speed control. This figure shows a system for performing torque control for simplicity. In this figure, in order to clarify the coordinate system of voltage and current, these signals are given a foot symbol t (uvw coordinate system), s (αβ fixed coordinate system), r (γδ quasi-synchronous coordinate system). Yes. Furthermore, in order to ensure simplicity, 3 × 1 or 2 × 1 vector signals are represented by a single thick signal line.

  Among the drive control devices, the rotor magnetic flux estimator 7 is related to the present invention. In this embodiment, the rotor magnetic flux estimator 7 is input with a voltage command value as a driving voltage equivalent value and an actual measured current value (true value) as a driving current equivalent value. From the rotor magnetic flux estimator 7, the cosine sine value of the phase of the γδ quasi-synchronous coordinate system, the speed of the γδ quasi-synchronous coordinate system, the amplitude estimated value of the rotor magnetic flux equivalent value (normalized rotor magnetic flux), the rotor (electricity) ) The estimated speed value is output. FIG. 3 shows the internal configuration of the rotor magnetic flux estimator 7. The rotor magnetic flux estimator 7 is mainly composed of a magnetic flux amplitude estimator 7a, a coordinate system speed estimator 7b, an integrator 7c, and a cosine sine generator 7d.

（１２ａ）式は、（８ｂ）式の第１行から得ている。（１２ｂ）式は、実質的に（９ｃ）式と同一である。（１２ｃ）式は、（８ｂ）式の第２行から得ている。なお、速度推定値ω＾２ｎは、必ずしも必要ない。この点を考慮して、図３の磁束振幅推定器７ａでは破線を利用して描画している。The magnetic flux amplitude estimator 7a obtains the detected stator current value on the γδ quasi-synchronous coordinate system as an input signal, and uses the normalized rotor magnetic flux estimated value and the stator magnetic flux estimated value evaluated on the γδ quasi-synchronous coordinate system. Generate and output. The principle of this generation is derived from the mathematical model of equations (7) to (9). Specifically, it is as follows.

Equation (12a) is obtained from the first row of Equation (8b). Expression (12b) is substantially the same as Expression (9c). Equation (12c) is obtained from the second row of equation (8b). Note that the estimated speed value ω ^ 2n is not necessarily required. Considering this point, the magnetic flux amplitude estimator 7a in FIG.

上式では、電圧相当値として電圧指令値を利用している。頭符＊は当該信号の指令値を意味する。固定子磁束相当φ＾１γは、磁束振幅推定器７ａから得ている。The actual configuration of the coordinate system speed estimator 7b will be described. The first embodiment is the following that exactly follows the first formula of the basic generation formula based on the invention of claim 1.

In the above equation, the voltage command value is used as the voltage equivalent value. The prefix * means the command value of the signal. The stator flux equivalent φ ^ 1γ is obtained from the magnetic flux amplitude estimator 7a.

座標系位相θ＾２ｆは、余弦正弦発生器７ｄで次式のように余弦値、正弦値に変換され、ベクトル回転器５ａ、５ｂへ向け出力されている。

The coordinate system speed ωγ generated by the coordinate system speed estimator 7b is integrated by the integrator 7c and converted into the coordinate system phase θ ^ 2f. The integration process performed by the integrator 7c is basically a simple integration expressed by the following equation.

The coordinate system phase θ ^ 2f is converted into a cosine value and a sine value by the cosine sine generator 7d as shown in the following expression, and output to the vector rotators 5a and 5b.

Various embodiments can be considered for the coordinate system speed estimator. The second embodiment is the following that exactly follows the second formula of the generation basic formula based on the invention of claim 1.

上式におけるＲＬｍｔは、変化率制限処理を意味する。ＲＬｍｔの処理対象信号ω’γ、すなわち処理前信号ω’γは、（１３）式または（１６）式で生成したものを利用すればよい。請求項２の発明は、請求項１の発明に追加処理を施すものである。The third embodiment of the configuration of the coordinate system speed estimator is based on the invention of claim 2 and is described by the following equation.

RLmt in the above equation means a change rate limiting process. What is necessary is just to use what was produced | generated by (13) Formula or (16) Formula RLmt process target signal ω′γ, that is, the pre-processing signal ω′γ. The invention of claim 2 is the one in which an additional process is performed on the invention of claim 1.

上式における記号〈〉は、ローパスフィルタ処理を意味する。処理原理は、（２）式の生成基本式に従っている。先ず、まずの分母の信号と分子の信号をそれぞれ個別にローパスフィルタ処理している。次に、フィルタ処理後の信号を生成基本式に準拠して除算して、γδ準同期座標系速度ωγを生成するようにしている。The fourth embodiment of the configuration of the coordinate system speed estimator is based on the invention of claim 3 and is described as the following equation.

The symbol <> in the above equation means low-pass filter processing. The processing principle is in accordance with the generation basic formula of formula (2). First, the first denominator signal and the numerator signal are individually low-pass filtered. Next, the filtered signal is divided in accordance with the generation basic formula to generate the γδ quasi-synchronous coordinate system speed ωγ.

「生成基本式に準拠して生成」は、上記のような生成も包含することを指摘しておく。The generation of the coordinate system speed in the coordinate system speed estimator may be performed without using division so that the following equation mathematically equivalent to the generation basic expression is established.

It should be pointed out that “generation according to the generation basic formula” also includes generation as described above.

  Regarding the magnetic flux amplitude estimator 7a, the integrator 7c, and the cosine sine generator 7d in the second to fifth embodiments, the same ones as in the first embodiment can be used. As a matter of course, a modified version of these may be used as necessary.

  In the embodiment described with reference to FIGS. 2 to 3, the stator voltage command value is used as the driving voltage equivalent value. It should be pointed out that other voltage equivalent values including the true voltage value (actually measured value) may be used as the driving voltage equivalent value.

  The present invention has been described specifically and in detail using a plurality of embodiments with reference to various drawings. The present invention described above can be variously modified and changed by those having ordinary knowledge in the technical field to which the present invention belongs without departing from the technical scope of the present invention. It should be pointed out that it is not limited to.

  The present invention can be widely used for applications that require sensorless driving of induction motors.

DESCRIPTION OF SYMBOLS 1 Induction motor 2 Power converter 3 Current detector 4a 3 phase 2 phase converter 4b 2 phase 3 phase converter 5a Vector rotator 5b Vector rotator 6 Current controller 7 Rotor magnetic flux estimator 7a Magnetic flux amplitude estimator 7b Coordinates System speed estimator 7c Integrator 7d Cosine sine generator 8 Magnetic flux controller 9 Command converter

Claims (3)

Used in a drive control device for an induction motor, the equivalent value of the drive voltage on the γδ quasi-synchronous coordinate system and the drive for the purpose of convergence to the dq synchronous coordinate system with the rotor magnetic flux phase as the d-axis phase A phase generation device including at least means for generating a velocity and a phase of a γδ quasi-synchronous coordinate system using an equivalent value of a current as an input signal,
The driving voltage equivalent value γ-axis element and δ-axis element are v1γ and v1δ, respectively, the driving current equivalent value γ-axis element and the δ-axis element are i1γ and i1δ, respectively, and the stator magnetic flux equivalent value γ-axis element. Is φ ^ 1γ, the stator resistance is R1, the stator total leakage inductance is l1t, s is the differential operator d / dt, and the sign function sgn is defined as follows:

A speed ωγ of the γδ quasi-synchronous coordinate system is generated according to the following generation basic formula having a positive gain g3,

A phase generation apparatus characterized in that the generated coordinate system velocity ωγ is integrated to generate a phase of a γδ quasi-synchronous coordinate system. The phase generation device according to claim 1, wherein a signal obtained by additionally subjecting a signal generated in accordance with the generation basic formula to a rate-of-change limiting process is defined as a final velocity of the γδ quasi-synchronous coordinate system. The phase generation device according to claim 1, wherein The phase generation device according to claim 1, wherein a signal corresponding to a denominator and a numerator of the generation basic formula is individually filtered, and a signal after the filter processing is divided in accordance with the generation basic formula. 2. The phase generator according to claim 1, wherein a γδ quasi-synchronous coordinate system speed ωγ is generated.

Images