JPS6070987A - Vector controller of induction motor - Google Patents

Abstract

PURPOSE:To obtain a preferably controlling accuracy by correcting the primary current command signal by a speed deviation signal and considering an iron loss and the secondary leakage reactance. CONSTITUTION:The primary current command signal generating means 7 is an adder in which an inverter 7' is provided only in a cosine wave circuit of an exciting current component command signal E to generate the primary current command signal G corresponding to the sum of a vectors of the signal E and a torque current component command signal F. This signal G becomes a set of a sine wave and a cosine wave. Correcting means 11 corrects the signal G on the basis of a speed deviation signal C to output the primary current command signal L. Thus, the influence of the second leakage reactance current component is considered for a current deviation signal K', and an induction motor 1 is held in preferable controlling accuracy in a wide range.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an improvement in a vector control device for an induction motor. In particular, the present invention relates to improvements that enable accurate torque control over a wide range.

(2) Background of the technology An induction motor operates at a speed ((1-
5) It rotates with f) and generates a torque proportional to the slip (S), and this torque is also φI2 (however,
Since I2 is also proportional to the secondary current), assuming a specific induction motor, the frequency (f) is higher than the rotational speed ((1-3)f) at a certain time by the slip frequency (s f), and the motor is An excitation current (■o) that generates a rotating magnetic field (φ) that generates a secondary voltage (E2) of an appropriate value at
By supplying the primary current (11), which is the vector sum of the -order conversion value (I2°) of the secondary current (I2) that generates the desired torque, to the -order winding, the rotational speed and torque can be adjusted to the desired value. It can be controlled as follows.

One of the control methods for induction motors based on this principle is the vector control method. The present invention is an improvement on this vector control method.

(3) Prior Art and Problems The vector control system for induction motors in the prior art was designed by regarding the induction motor as a simplified equivalent circuit shown in FIG. In other words, ignoring the iron loss current component and secondary leakage reactance current component, as shown in Figure 2,
Assuming an excitation current (■o) in the same phase as the rotating magnetic field (φ), and assuming a secondary voltage (E2) generated 80° behind this and a secondary current (I2) in the same phase, convert this into a primary Value (■2
The primary current (I1), which is the vector sum of the current (°) and the excitation current (■o), is supplied to the negative winding.

In order to realize this idea, a vector control device for an induction motor in the prior art has a basic configuration shown in FIG. That is, in order to control the induction motor, a speed detection means 2 and a current detection means 3 are provided, and the difference between the speed command signal A and the speed signal B which is the output of the speed detection means 2 is used as a speed deviation signal C. At this time, if speed command signal A represents f, speed signal B represents (1-s)f, and therefore speed deviation signal C represents sf. The speed deviation signal C and the speed signal B are applied to the rotating magnetic field frequency generating means 4 to obtain a rotating magnetic field frequency signal consisting of a set of a sine wave and a cosine wave of the rotating magnetic field frequency (f). This rotating magnetic field frequency signal is divided into two, and one is applied to the excitation current component command generation means 5, where the amplitude is adjusted to a value corresponding to the excitation current, and a combination of a sine wave and a cosine wave is generated. The excitation current component command signal E is made up of: The exciting current is
Any value that is suitable for generating a rotating magnetic field (φ) that is suitable for generating a secondary voltage (E2) of an appropriate value is sufficient, so once the design constants of the induction motor have been determined, they should be determined accordingly. . Therefore, the above adjustment is possible by multiplying by a specific coefficient. is adjusted to a value corresponding to the desired torque, and this is also used as a torque current component command signal F consisting of a set of a sine wave and a cosine wave. Add the sine wave of the excitation current component command signal E and the cosine wave of the torque current component command signal F, and add the inverted signal of the cosine wave of the excitation current component command signal E and the sine wave of the torque current component command signal F. A primary current command signal G is generated by the primary current command generating means 7. This - next current command signal G
has a frequency f and an amplitude I shown in FIG.
It is a two-phase AC signal corresponding to 1, and consists of a set of sine waves and cosine waves. If the induction motor has three phases, it is converted to three-phase AC using the two-phase to three-phase conversion circuit 8 to become the three-phase-secondary current command signal G''.This three-phase-secondary current command signal G'
is compared with the output (current signal H) of the current detection means 3 to generate a current deviation signal K, which is amplified and applied to the alternating current generator 9 to generate a desired alternating current. . The induction motor l is supplied with this alternating current,
It rotates at a desired speed regardless of the size of the load. In this prior art vector control device for an induction motor, the core loss current component and the secondary leakage reactance current component are ignored as described above, so the drawback is that it is difficult to maintain good control accuracy. be.

(4) Purpose of the Invention The purpose of the present invention is to eliminate this drawback, and in a vector control device for an induction motor configured as described above,
An object of the present invention is to provide a vector control device for an induction motor having good control accuracy.

(5) Configuration of the Invention The configuration of the present invention is a speed deviation signal detection means for comparing the speed command signal A and the speed signal B and detecting the speed deviation signal C!
0, the speed deviation signal C, and the speed signal B are input, and a rotating magnetic field frequency generating means 4 generates a rotating magnetic field frequency signal consisting of a sine wave and a cosine wave combination of the rotating magnetic field frequency; excitation current component command signal generating means 5 for generating an excitation current component command signal E consisting of a set of a sine wave and a cosine wave by adjusting the amplitudes of a sine wave and a cosine wave constituting the signal; and the rotating magnetic field frequency. a torque current component command signal generating means 6 which receives the signal R and the speed deviation signal C and generates a torque current component command signal F having an amplitude proportional to the torque and consisting of a set of a sine wave and a cosine wave; Adding the sine wave of the component command signal F and the inverted signal of the cosine wave of the excitation current component command signal E, and adding the cosine wave of the torque current component command signal F and the sine wave of the excitation current component command signal E. A primary current command signal generating means 7 generates a primary current command signal G which is composed of a set of a sine wave and a cosine wave and whose amplitude is proportional to the vector sum of the excitation current component command signal E and the torque current component command signal F. and the next current command signal G
and a current deviation signal generating means 12 that compares and amplifies the output signal G' of the two-phase multiphase conversion means 8 and the current signal H to generate a current deviation signal K. In a vector control device for an induction motor, the above-mentioned negative current command signal G, where ■2 is the torque current component command signal, ■ is the excitation current component command signal, and ■ is the excitation inductance of the induction motor. A vector control device for an induction motor is characterized in that it has correction means 11 for correcting secondary leakage inductance of the induction motor.

The present invention is designed to ignore the iron loss current component and secondary leakage reactance current component, which are the two causes of the above-mentioned drawbacks, since the value of the former is small, but to take into account the influence of the latter. be.

Refer to Fig. 4 In the conventional vector control device for an induction motor, the vector diagram is simplified as shown in Fig. 2, but if the secondary leakage reactance current component is taken into account, I° is J2°. It changes like J2° and ■. The vector sum will change from ■1 to Jl.

Therefore, leaving the absolute value of Jl unchanged, it is moved to the phase (1) in vector control to obtain Jl.

It would be sufficient to correct it as follows.

Let the excitation current component after correction be ■°, and let the phase angle of ■1 in vector control be φ.

I,’=Jicosφ, It is.

On the other hand, if the torque current component after correction is ■i, then I'
= J' gin φ l.

See Figure 5. Here, for symbol simplification, Io, which is the same scalar quantity as J″2, is represented by ■, J is represented by I1, 2 2 1 1 is represented by I, Io is represented by I, and ■i is represented by ItO. M
, respectively, and calculate the correction coefficient based on the above idea.

First, 1 = I 2 + I 2-211 cos(20θ)l
■ 2 m2 2 However, θ is the secondary current X20 power factor angle.

holds true.

Also, ■ in Figure 5 is Ji in Figure 4 (the scalar quantity is Jl
), so 1 Furthermore, since , the excitation current component is .

Therefore, the exciting current component is 2 becomes.

On the other hand, similarly, the torque current component is becomes.

By the way, if the excitation inductance is , and the secondary leakage inductance is , the slip angular frequency condition is 3 Substituting this into the above equation, it becomes .

Therefore, the primary current command signal G in the vector control device for the induction motor in the prior art described above.

Or both the excitation current component command signal E and the torque current component command signal F.

It would be a good thing to do.

In order to realize this correction, I, u, recommendation- Since S is a constant and I2 is proportional to S.

Let the speed deviation signal C representing sf represent I2, and provide a correction means that receives the speed deviation signal C and performs the above calculation using other appropriate constants, and the output of this correction means As described above, the correction may be made by multiplying the -order current command signal G, ゛ or both the excitation current component command signal E and the torque current component command signal F.

(6) Embodiments of the Invention Hereinafter, vector control devices for induction motors according to embodiments of the present invention will be further described with reference to the drawings.

Referring to FIG. 6, 1 is an induction motor to be controlled, 2 is speed detection means, and 3 is current detection means. A is a speed command signal, which is detected by the speed detection means 2 in the speed deviation signal detection means lO.
A speed deviation signal C is generated by comparing the speed signal B which is the output of the speed signal B. As mentioned above, this speed deviation signal C represents the slip frequency (sf). 4 is a rotating magnetic field frequency generating means 5 to which a speed signal B representing the slip rotational speed (f - sf) and a speed deviation signal C representing sf are inputted;
A rotating magnetic field frequency signal consisting of a set of a sine wave and a cosine wave of a rotating magnetic field frequency (f) is generated.

5 is an excitation current component generating means, which applies a constant determined by the design constant of the induction motor (an excitation current component that generates an appropriate rotating magnetic field to the induction motor) to each of the sine wave and cosine wave of the rotating magnetic field frequency signal. The excitation current component command signal E is generated by multiplying the excitation current component by a constant (determined by the strength of the current). This signal E is a set of a sine wave and a cosine wave, the frequency of which is f, and the amplitude of which corresponds to the magnitude of the excitation current determined by the motor. Therefore, l5in2πft and I
It can be expressed as cos2πft. 6 is a torque current component command signal generating means, which generates a torque current component command signal F by multiplying each of the sine wave and cosine wave of the rotating magnetic field frequency signal by a speed deviation signal C representing sf. This signal F has a frequency of f and an amplitude of a sine wave and a cosine wave whose amplitude corresponds to the slip frequency sf. Therefore, it can be expressed as I5in2πft and Itcos2πft.

7 is a primary current command signal generation means, Itcos2
πf t + Ill5in 2 πf t,
I tsin2 tc f t −I mcog2 π
f t is calculated.

Therefore, the -order current command signal generation means 7 is an adder in which an inverter 7° is provided only in the cosine wave circuit of the excitation current component command signal E, and the excitation current component command signal E and the torque current component command signal F. A primary current command signal G corresponding to the vector sum of .

This signal G also consists of a set of a sine wave and a cosine wave. Reference numeral 11 denotes a correction means according to the gist of the present invention, which converts the negative primary current command signal G and outputs a corrected primary current command signal.

1.1.1. is a constant, only the variable I2 is in one layer, and the variable I2 can be calculated based on the speed deviation signal C, so the correction means 11 may be configured as follows.

Referring to FIG. 7, ill is a multiplier which receives a speed deviation signal C representing the slip frequency (sf) and outputs a signal a representing (I)2. 112 has the amplification factor manually (It sentence,
, /l, +l,) is output. on the other hand,
113 is a reference voltage, and 114 is a voltage divider. The output C of the voltage divider 114 represents . 115 is a multiplier which squares the signal C representing the suppuration layer and outputs the signal ■d representing (■)2. tte, 117 is a resistor.
11B is an adder to which signals a and d are input.

2 A signal e representing (■ +1.) is output.

A divider 118 divides the signal S by the signal e and outputs the following. 120 and 121 are resistors. The signal g is a reference voltage and represents the number "t"'. 122 is an adder which adds the signal g and the signal f and outputs a correction coefficient signal that can be requested. 123 is a multiplier, which corresponds to the vector sum of the excitation current component command signal E and the torque current component command signal F, and outputs each of the primary current command signals G consisting of a set of sine waves and cosine waves (sine wave and cosine wave). is multiplied by a signal G representing the correction coefficient. As a result, biphasic symbols corresponding to ■1, t, and 4 in FIG. 5 are obtained.

Referring again to FIG. 6, reference numeral 8 denotes a two-phase to three-phase conversion means, which converts the corrected primary current command signal consisting of a combination of a sine wave and a cosine wave into a three-phase signal L'.

9 This three-phase signal L' and the current signal H which is the output of the current detecting means 3 are applied to the current deviation signal generating means 12 to generate a current deviation signal. Reference numeral 9 denotes an alternating current generator, which generates a three-phase alternating current controlled by the current deviation signal ', and this current is applied to the induction motor l.

In the above current deviation signal, ' corresponds to Io shown in Fig. 5 and J'' shown in Fig. 4, and the influence of the secondary leakage reactance current component is taken into account, so the induction motor l has good performance over a wide range. Control accuracy can be maintained.

(7) As described in detail, according to the present invention, it is possible to provide a vector control device for an induction motor that has good control accuracy.

[Brief explanation of drawings]

FIG. 1 is a simplified equivalent circuit that is the basis of a vector control method for an induction motor in the prior art, and FIG. 2 is a vector diagram of a vector control method for an induction motor in the prior art. FIG. 3 is a block diagram of a conventional vector control device for an induction motor. FIGS. 4 and 5 are vector diagrams as auxiliary diagrams for explaining the concept of correction for the vector control method of an induction motor in the prior art. FIG. 6 is a block diagram of a vector control device for an induction motor according to an embodiment of the present invention. FIG. 7 is a block diagram of a correction means according to the gist of the present invention. l-Ya・Induction motor, 2...Speed detection means, 3・O
・Current detection means, 4... Rotating magnetic field frequency generation means,
5. Excitation current component command generation means, 6.. Torque current component command generation means, 7.-Next current command generation means, 8. 2-phase polyphase conversion means, 9. Conflict/AC generation. Device, lO... Speed deviation signal detection means, ll...
Correction means 12...Current deviation signal generation means, A...
Speed command signal, B...speed signal, C1111φ speed deviation signal, D-φ・rotating magnetic field frequency signal, E・e
- Excitation current component command signal, F/Fist/torque current component command signal, GΦ...-Next current command signal, Go...
Output signal of two-phase polyphase conversion means, H-...Current signal, K
Φ...Current deviation signal, ■...Secondary current, ■...
Electromagnetic current, m Sentence... Exciting inductance, Standing 2... Secondary leakage inductance, 111... Multiplier, 112-...
113... Reference voltage, 114... Voltage divider, 115... Multiplier, 11B. 11? ...Resistance, 118 ・Life/Adder, 11
9--divider, 120, 121---resistance, 12
2-...adder, 1239φ/multiplier, Lo...
Primary current command signal after correction, K'...deviation signal after correction. Agent: Patent Attorney Makoto Samukawa Procedural Amendment (Spontaneous) December 77, 1982 Kazuo Wakasugi, Commissioner of the Patent Office, 1982 Patent Application No. 177044 2, Title of Invention Vector Control Device for Induction Motor 3, Relationship with the person making the amendment Patent applicant address 3-5-1 Asahigaoka, Hino-shi, Tokyo Name FANUC Corporation Representative Seieemon Inaba 4, agent 165 Address 1-4-5 Nogata, Nakano-ku, Tokyo 6. Subject of amendment The detailed explanation of the invention in the specification is amended as follows, as shown in Column 7 of the detailed explanation of the specification and attached sheet of contents of the amendment. (1) Correct the formula %rI' on page 10, line 9 to I. (2) The formula on page 10, line 13 (3) The formula on page 11, line 1 (4) The formula on page 11, line 1θ is corrected. (5) Formula on page 11, line 17 (6) Formula on page 12, line 1 (7) Corrected as formula on page 12, line 6. (8) Formula on page 12, line 7 (9) Correct the formula on page 12, line 12. (10) Correct the formula on page 13, first line. (11) Formula on page 13, line 5 (12) Formula on page 13, line 6 (13) Corrected as formula on page 13, line 7. (14) Correct the formula on page 13, line 8. that's all

Claims (1)

[Scope of Claims] A speed deviation signal detecting means 1° for detecting a speed deviation signal C by comparing a speed command signal A and a speed signal B, and a speed deviation signal detecting means 1° for detecting a speed deviation signal C by comparing a speed command signal A and a speed signal B; , a rotating magnetic field frequency generating means 4 for generating a rotating magnetic field frequency signal consisting of a set of a sine wave and a cosine wave of the rotating magnetic field frequency, and adjusting the amplitude of the sine wave and cosine wave constituting the rotating magnetic field frequency signal. The excitation current component command signal generation means 5 generates an excitation current component command signal E consisting of a set of a sine wave and a cosine wave. A torque current component command signal generating means 6 generates a torque current component command signal F which is proportional to , and is composed of a set of a sine wave and a cosine wave, and a sine wave of the torque current component command signal F and the excitation current component command signal E. The cosine wave of the torque current component command signal F and the sine wave of the excitation current component command signal E are added to form a set of a sine wave and a cosine wave, and the amplitude is the excitation current. a primary current command signal generating means 7 that generates a primary current command signal G proportional to the vector sum of the component command signal E and the torque current component command signal F; and converts the secondary current command signal G into two-phase polyphase conversion. means 8, and current deviation signal generating means for comparing and amplifying the output signal G° of the two-phase multiphase converting means 8 and the current signal H to generate a current deviation signal K! In a vector control device for an induction motor, the vector control device for an induction motor has: ■ A vector control device for an induction motor characterized by having a correction means 11 for correcting secondary leakage inductance of the induction motor.