JPH04183291A - Vector controller for induction motor - Google Patents

Abstract

PURPOSE:To hold accelerating/decelerating characteristics excellent without bad influence due to compensation even if the speed of a motor is varied by performing a secondary resistance compensation without influence of variation in a primary resistance. CONSTITUTION:A PI amplifier 7 has a proportional element 71 for calculating (i1gamma*-i1gamma)XL'/Ts corresponding to LsigmaPi1gamma and an integrating element 72 for integrating (i1gamma*-i1gamma), outputs the sum of a proportional term output from the element 71 and the integrating term output from the element 72 as V1gamma, and outputs the integrating term output as V1gamma1. A PI amplifier 8 has a proportional element 81 for calculating (i1delta*-i1delta)XLsigma/Ts corresponding to LsigmaPi1delta and an integrating element 82 for integrating (i1gamma*-i1g), outputs the sum of the proportional term output from the element 81 and the integrating term output from the element 82 as V1delta, and outputs the integrating term output from the element 82 as V1delta1.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a vector control device for an induction motor.

B0 Summary of the Invention The present invention provides a vector control system that includes a slip angular frequency calculation unit that calculates a slip angular frequency based on the components of each axis of the primary current in an orthogonal two-axis coordinate system and a secondary time constant in an induction motor. In the device, the rotational coordinate γ with the -blow mold flow as the reference axis
- Focusing on the fact that the δ-axis component of the primary voltage on the δ-axis is not affected by the size of the primary resistance, the target value of the slip angular frequency is corrected based on the fluctuation component, and the compensation calculation is temporarily stopped when the speed changes. By doing so, it is possible to perform ideal compensation for secondary resistance changes that are not affected by primary resistance changes, thereby improving torque control accuracy and maintaining good acceleration/deceleration characteristics when speed changes.

Furthermore, we focused on the fact that during no-load operation, the torque current becomes zero, and the influence of secondary resistance changes does not appear on the blow mold pressure fluctuations. These compensations are only possible by calculating the inductance.

C9 Prior Art Vector control of induction motors, which controls secondary magnetic flux and secondary current orthogonal thereto in a non-interfering manner, has been widely applied.

In the case of a three-phase induction motor, this vector control treats the current and magnetic flux as vectors in a d-q coordinate system of two orthogonal axes that rotate at the same speed as the rotating magnetic field generated by the power supply, and calculates the calculation results by three-phase induction motors.
This is a method of controlling by converting it into a current command value for each phase of the phase power supply.

Describing the specific method, the voltage equation in the 1d-q coordinate system is expressed by the following equation (1).

(Left below) ・・・・・・・・・(1) However, ω, = ω-ω, La = (L, L2-M2)/
It is L2.

Here, v14 + vIQ are the primary voltages d and q, respectively.
axis component, 11d+i1q are the d and q axis components of the primary current, λ2d, respectively.
．． λ2Q are the d and q axis components of the secondary magnetic flux, R, , R
2 are the primary and secondary resistances, respectively, L1dL2dM are the primary, secondary, and exciting inductances, respectively, ω, ω■. ω represents the primary power supply angular frequency, the first rotor angular frequency, and the slip angular frequency, respectively, and P represents d/d t .

If the d-axis is placed on the secondary magnetic flux in the d-q coordinate system, λ2Q
-0. At this time, λ2d-Φ2-constant, 1H=Q,
12q=12, which enables orthogonal control of torque and magnetic flux similar to a DC machine.

On the other hand, the secondary magnetic flux has the following relationship.

λ2d=MiHa+L212d) ・・・・・・・・・(2) λ2d=Mil, + L 2 i 2゜From the vector control condition, iz++=o, and from equation (2), λ2d=M
i Hd.

Also, from λ・, −〇, i1d=−mount・12d,
i1q is proportional to torque current.

Next, from the 4th line of equation (1), equation (3) is obtained, and this (3)
Determining the slip angular frequency condition from the formula, ω is (4)
Expressed by the formula.

The above are vector control conditions when controlling so that the secondary magnetic flux coincides with the d-axis. Therefore, in order to perform vector control, it is necessary to set i1d to λ2d/M and control ω so that equation (4) holds true.

Here, the secondary resistance R2 used to calculate the slip angular frequency ω,
Since the resistance value changes due to temperature changes such as ambient temperature and rotor self-heating, the change in resistance value is estimated based on the output voltage of the motor, and the target value of the slip angular frequency ω is determined from this change. It is necessary to make corrections to compensate for fluctuations in generated torque due to secondary resistance changes. If the change in secondary resistance is ignored, torque control accuracy and torque response will deteriorate. For example, if the output voltage of the inverter is used as is to estimate the change in the secondary resistance, the change in the primary resistance will be incorporated, so the signal used for estimation should be a signal that is not affected by the primary resistance. This is desirable.

For this reason, a control circuit shown in FIG. 8 has already been proposed. 1 in the figure is the excitation current command section, and the angular frequency ω
, λ2d*/M* is set as the target value i1d* of i1d until ω exceeds a certain value, and i1d* is decreased when ω exceeds a certain value. When the target value or ideal value is indicated with * below, the deviation of the speed commands ω■* and ω is set as i1d* through the speed amplifier 2, and i (d*, i1q* based on the d-q axis Ideal values of the above primary voltages V1d*, V1q
Calculate * and correct the voltage fluctuation due to changes in primary and secondary resistance as i1d* = i1d, I IQ* = 1
If controlled so that it becomes 1+, i 1γ*= i 1.
Δv1d is obtained for the PI amplifier 3□ that controls ll
Δv1 for the PI amplifier 32 that controls +++*=j+++
δI9 is obtained. △v1d+Δv1δIQ includes both primary and secondary resistance changes as well as voltage fluctuations, so if you compensate for secondary resistance changes by finding a component that does not include voltage fluctuations due to primary resistance changes, the primary Compensation that is not affected by resistance changes becomes possible. Therefore, a rotational coordinate γ-δ axis with the reference axis γ placed on the vector of the -blow mold flow 11 is taken, and the one-blow mold pressure variation Δvl of this δ axis is determined by the overburden correction calculating section 33. This Δv1δl is expressed by an equation that does not include the primary resistance R1, and therefore is not affected by the primary resistance R1. Since Δvl is also used in the present invention, it will be explained in detail in the section explaining the contents of the present invention.

Fig. 6 is a vector diagram showing the relationship between the d-q axis and the γ-δ axis, voltage and current, and Fig. 7 is a vector diagram showing the primary voltage fluctuation. voltage, secondary voltage,
Δv1 is the primary voltage fluctuation, Δv1δ02dΔv1δl,
are the γ-axis component and δ-axis component of the variation, respectively, and ψ is the γ-axis and d
The phase difference with the shaft, Io is the excitation current, and I2 is the torque current. Δvl is expressed by the following equation (5).

Δv1δ16=-Δv1δ1d”S1nψ+Δv1δI
QCOSψ-(5) where cosψ-10/I +=
i Ia/ i+v, sin ψ-12/ I 1-
i + a/ i Iy Then, the slip correction calculation section 33 calculates the correction amount Δω■ of the slip angular frequency corresponding to the secondary resistance change based on Δvl, and the slip angular frequency calculation section 34 calculates the correction amount Δω■ of the slip angular frequency based on Δvl. The added value of and Δω■ is set as the target value of the slip angular frequency, and the rotor angular frequency ω■ is added to this to set the target value of the angular frequency ω=dθ/dt of the primary voltage. In FIG. 8, 1d is a polar coordinate conversion section, 36 is a coordinate conversion section, and 4. is a PWM circuit, 4□ is an inverter, IM is an induction motor, PP is a pulse pickup section, and 43 is a speed detection section.

D7 Problems to be Solved by the Invention - Since the blow mold pressure variation Δv1,1 Δv1δ1q includes both the primary resistance variation and the secondary resistance variation, in the circuit of FIG. Δv1 at 33
4. From Δv1δ1q, Δ16, which is not affected by the primary resistance change, is further calculated, and from this Δv1δ1g, Δω■ is further calculated.

■ When performing field control, what is λ2d and i1δ? (1)
From the third line of the equation, the following equation (6) holds true.

Since λ29=0, equation (7) holds true.

λ2dL2 =-(1+-P)...(7) R
2 From equation (7), it can be seen that during field control, i1d is controlled linearly with respect to changes in λ2d. In other words, when the field command λ2d* is changing, λ2d=Micd does not hold.

However, in the conventional circuit, since no consideration is given to field control, the excitation current i1d is kept constant, i.e., i□=λ2 d/M, and the theoretical development is performed to execute the slip correction calculation. Therefore, in the field control region, the set value of the slip angle frequency cannot be calculated accurately.
It wasn't an effective method.

An object of the present invention is to perform ideal compensation that is not affected by changes in primary resistance when compensating for changes in secondary resistance in the slip angular frequency calculation formula, and to compensate for changes in secondary resistance even when the speed of the motor changes. It is possible to maintain good acceleration/deceleration characteristics without any adverse effects caused by the compensation, and furthermore, the calculation of the target value of the slip angular frequency is easier than in the previously proposed method, and it is also effective when performing field control. The purpose of this invention is to propose a vector control device.

Another object of the present invention is to provide a vector control device capable of compensating for changes in primary resistance and excitation inductance.

Means and operation for solving the E0 problem As mentioned above, not only the secondary resistance but also the primary resistance changes depending on the temperature, so it is ideal to perform secondary resistance compensation without being affected by changes in the primary resistance. .

Here, in the present invention, the variation amount Δvl of the δ-axis component of the primary voltage is used as in the circuit of FIG. 8, and a control method that is one step further is adopted.

That is, in the vector control shown in FIG.
1d, and the torque current i1q was controlled to maintain orthogonality.

This time, we will use this rotational coordinate as the γ-δ axis and use the γ-axis as a one-shot style!
, I considered how to set it up and control it.

However, since vector control naturally requires control on the d-q axes, the power source angular frequency ω.

A disconnection control method was adopted in which the d-q axes and the γ-δ axes, which rotate at the same speed and have different phases, are used.

- When considered on the γ-δ axis based on the blow mold flow 11, the primary voltage fluctuation due to the secondary resistance change is the d-axis fluctuation Δv, J
When detected, the voltage component becomes a voltage component that does not include voltage fluctuations due to the primary resistance, making it possible to perform robust secondary resistance compensation.

(Left below) Therefore, the ideal blow mold pressure vl Y ** on the γ-δ axis
Calculate v1δ* and correct the voltage fluctuation due to changes in primary resistance and secondary resistance by 1 +t= I I , l 1d=
This is executed by controlling the value to be 0. By controlling in this way, ll? = PI that controls Il
Δv1δly is obtained as the amplifier output, and Δv1δl is obtained as the PI amplifier output that controls 11g-0.

Since Δv1δl does not include a voltage component due to a primary resistance change, it can be used to compensate for a secondary resistance change. In other words, if Δv1δ1d is used to compensate for the secondary resistance change, ideal compensation that is not influenced by the primary resistance change can be performed.

In this way, if the γ-δ axis is used with the −blow mold flow 11 as the reference value, there is an advantage that the primary resistance change data used to compensate for the secondary resistance change can be directly obtained on the δ axis.

In addition, in the present invention, from the above equation (7), the field command λ2d*
Since λ2d-Mil□ does not hold when is changing, λ2d/M and lla are used separately.

Furthermore, a speed change of the electric motor is detected, and when there is a speed change, the compensation for the secondary resistance change is temporarily stopped, the amount of compensation up to that point is held, and when the speed change disappears, the compensation is performed again. As a result, an accurate slip frequency can be given even when the speed changes, and good acceleration/deceleration characteristics can be maintained.

The present invention will be specifically explained in detail below.

(2) Vector control conditions when using γ-δ axes FIG. 3 is an asymmetric T-I type equivalent circuit of an induction motor, and FIG. 4 is a vector diagram corresponding to this equivalent circuit.

Now if we take the γ axis above the primary current 11,' +, -I 1, i
1g=0. The same formula as formula (1) shown in the "Prior art" section also holds true for the γ-δ axis, so if d and q in formula (1) are changed to γ and δ, respectively, line 1d4 of formula (1) Equations (8) and (9) hold true.

If we remove the term that includes P, we can find a condition for ω that always holds true. The following equation can be obtained from equation (9).

By substituting equation (10) into equation (8), the following equation is obtained, and therefore equation (11) holds true.

Here, the relationship between λ2d and λ22dλ2d is as follows.

λ2d; λ2d cosψ ) ・・・・・・(12) λ2d=−λ2d sinψ λ2,2+λ2d2=λ2d2 ,・−−−−
(13) (12), Substituting equations (13) into equation (11) yields the following equation.

211d As above, the γ-axis is set above the primary current 11 and 11? =
II, 1la-Q, and if the vector control conditions on the d-q axes are satisfied, ω becomes ``
It was found that the equation (4) in the section ``Prior Art'' is expressed by the same equation, and the same conditions can be obtained. However, if we consider the field control region and treat it as λ2d≠Micd, then (14)
From the first stage of the equation, ωS is expressed as shown in equation (15).

■ Ideal voltage on the γ-δ axis 1 on the γ-δ axis. , *=■1di1d*=Q, so if we transform equation (1) taking this into consideration, we get the following (1
6) Equation is obtained.

(16) If the term with P is omitted, the equation becomes as shown in (17).

・・・・・・・・・(17) Here, when the vector control condition is satisfied, the following equation is established.

Therefore, equation (19) is obtained.

When the torque current command i1q* suddenly changes or when field control is entered and the excitation current command i1d* changes, (1
6) The term P i 1d that depends on Lσ in the equation cannot be ignored. The ideal voltage when this P term is considered is as follows.

■ Secondary magnetic flux fluctuation when secondary resistance changes Examine secondary magnetic flux fluctuation when secondary resistance changes.

The following equation is obtained from the 3rd and 4th lines of equation (1).

Multiplying equations (21) and (22) by L2/R2 yields the following.

Calculate λ2d from equations (23) and (2d). first·
・・・・・・・・・・・・(25) (25) From +(2d), λ2d becomes as follows.

Next, λ2d is determined from equations (23) and (2d).

Ma......(28)...(29) (29) Calculating λ2d from -(28) results in the following.

Here we make the following assumptions.

(a) Assuming that the current is controlled to flow according to the command value, 11v* = l It, i1d* = i1δ = 0
shall be. Also, the current on the d-q axis is i1d*=i1d,
11q*-i1d.

(b) If the secondary resistance change is K, R2=(1+K) can be expressed as follows.

M* M* (c) It is assumed that the excitation current is controlled as shown in equation (7), and therefore equation (32) holds true.

Assume that the time constant of the transient term Lz/R2=L2*/R2*. (Assume that R2 does not change in a short time.) Therefore,
The following formula holds true.

M* Substituting the above relational expressions into equations (27) and (30) and transforming them results in the following.

Here, the ideal value of the secondary magnetic flux on the γ-δ axis is expressed by the following equation.

Multiplying the denominator and numerator of equation (34) by i1d* and using equation (36), the secondary magnetic flux variation Δλ2d on the γ axis is (39)
It is expressed as follows.

Δλ2d−λ2d−λ2d* Also, multiplying the denominator and numerator of equation (35) by i1d*, (37
) equation, the secondary magnetic flux variation Δλ2° on the δ axis is (4
0) is expressed as follows.

Δλ2d=λ2d−λ2d* ■ Temporary voltage fluctuation when secondary magnetic flux fluctuates The primary voltage when the secondary magnetic flux fluctuates can be expressed as follows from equation (I6).

-The ideal value of blow mold pressure is expressed by equation (19), so (18
) From equations (19) and (41) that take into account equations, the voltage fluctuation Δv11 Δvl is as follows. However, Δ
λ25. The expansions of Δλ2d are (40) and (39), respectively.
It uses the formula.

Δv1δ ly ” V ly V I y *
・・・・・・・・・・・・(42) Δv1δ 1ll=
V 1e V 1d* (43) Here, since Vly includes R, i, and * components,
Vly also includes voltage fluctuations due to changes in the primary resistance R1. Therefore, considering the change in the primary resistance R1, (
42) The formula is as follows. However, 1 is the primary resistance change.

P・Δv1δ l t ”' V I r V l
v *・・・・・・・・・・・・(44) From the above, Δ
Since v1δly includes a variation in the primary resistance R1, it is inappropriate for use in compensating for changes in the secondary resistance R2. On the other hand, since Δv1δla does not include the R1 component, it is considered to be a voltage fluctuation component due to a secondary resistance change. Therefore, δ
If the secondary resistance compensation is performed by detecting the variation Δv1δl of the shaft blow-type pressure vl, the influence of the primary resistance R1 is not included, so there are the following advantages.

(i) Secondary resistance compensation can be performed without being affected by temperature changes in the primary resistance R1.

(ii) In the low speed range, the influence of the voltage drop in R becomes large, but since the δ-axis single-blow pressure Vl does not include the voltage drop in R1, secondary resistance compensation can be performed accurately even in the low speed range. It becomes possible to do so.

(ii) Δv1δl, if more secondary resistance compensation is performed, Δv
Only the voltage component due to the change in R1 is generated at 1δlt.

This allows estimation of R1. It is considered that R1 includes the voltage drop due to the resistance bone dead time of the primary resistance cable, vcI1 of the main circuit element, etc.

■ Calculation of secondary resistance change By transforming the equation (43), the following equation (45) is obtained.

(45) Therefore, if the single blow type pressure variation Δv1δl on the δ axis can be detected, the secondary resistance change K can be obtained from equation (45).

■ Method of identifying primary resistance and excitation inductance during no-load operation In addition to compensating for secondary resistance changes, the present invention can also identify primary resistance and excitation inductance as described below.

When the excitation inductance changes, the division ratio of the excitation current and torque current changes, and the primary voltage also changes.

- Since the blowing mold pressure changes in the same way even if the secondary resistance changes,
Changes in excitation inductance M and secondary resistance R2 cannot be distinguished. However, during no-load operation, the torque current is 11
Since q=o, the primary voltage fluctuation is not affected by the secondary resistance change. Therefore, the excitation inductance can be compensated using the primary voltage fluctuation during no-load operation.

The vector diagram during no-load operation is the fifth one from the T-I equivalent circuit.
It can be expressed as shown in the figure. During no-load operation, the torque current i1d""O, so the 1d-q axis and the γ-δ axis coincide. Therefore, let's consider the d-q axis. The primary voltage during no-load operation can be expressed as follows from equation (16). However, i
1q=O, and ignore the P term.

V1d=R111d Here we make the following assumptions.

(a) Assuming that the current is controlled to flow according to the command value, it is assumed that the current is i-th * -I Hd.

(b) Let AM be the change in excitation inductance.

(c) Let A be the change in primary resistance.

(d) Add an asterisk to the motor constant settings.

(e) Leakage inductance L is assumed to be small and changes are ignored.

Now, the ideal voltage during no-load operation can be expressed as follows from equation (46).

The primary voltage is expressed using the primary resistance change A1 and the excitation inductance change AM as follows.

V Ia-(L + A+)・R1*・i1d*(47
), From equation (48), the single blow type pressure fluctuations Δv1δla and Δv1δIQ during no-load operation are as follows.

From equation (49), the primary resistance change A and the excitation inductance change AM are as follows.

In a steady state where the excitation command does not change, λ2d*=M*i+
, *, so A2 becomes as follows.

From the above, it was found that it is possible to identify the primary resistance and excitation inductance by detecting the primary voltage fluctuation during no-load operation. In summary, it is as follows.

(a) d-axis single blow type pressure fluctuation Δv1. From this, the primary resistance change amount AI can be seen.

(b) The excitation inductance change AM can be found from the q-axis single-blow pressure variation Δv1δlt.

■ Means of the Invention If the target value R2* of the secondary resistance and the actual secondary resistance match, ω is determined based on equation (15), and ω
■* However, the secondary resistance changes depending on the temperature. Therefore, in the present invention, K is calculated using Δv1δl11, R2* is corrected using this K, and ω■* is obtained. ω■
In order to find *, the following (5
2) Use the formula.

On the other hand, the primary resistance also changes depending on the temperature, but Δv1δ is (4
3) As can be seen from the equation, since the value of the primary resistance is not included, compensation for the secondary resistance is not influenced by changes in the primary resistance. This point is common to the circuit shown in Fig. 8, but whereas the circuit in Fig. 8 performs current control in the d-Q coordinate system, the present invention controls the current in the γ-δ coordinate system. The primary voltage is controlled based on the control, and this causes the current control amplifier output to have Δv1δ12dΔv1δ1δ
is obtained, and this Δv1δl is used to compensate for the secondary resistance.

When the speed of the motor suddenly changes, errors occur in the slip frequency, primary station wave number, etc. due to a delay in speed detection, resulting in a deviation from ideal vector control conditions. In order to correct this, Δvl will also change, making it impossible to use it for secondary resistance variation compensation. Therefore, if secondary resistance fluctuation compensation is performed when the motor speed changes, an inaccurate slip frequency will be provided, which will deteriorate the characteristics during acceleration and deceleration. Therefore, based on the motor speed detection signal,
A speed change detection unit is provided to detect the presence or absence of a speed change, and when the speed change detection unit detects the presence of a speed change, it holds the value of the secondary resistance change before the speed change occurs and calculates the corresponding value. is stopped, and when the speed change detection section detects no speed change, the above calculation is restarted.

Specifically, a first coordinate conversion unit that calculates the target value 1 +t* (""I l) of the γ-axis component of the primary current and the phase ψ based on 11d*+i1q*, and λ2d*
and the excitation inductance M, λ2−/M, the first
The calculation result of the coordinate transformation unit and the command value ω of the power supply angular frequency.

Based on the target value of the γ and δ axis components of the primary voltage■1A*,
A means for calculating v1γ* and V1δ*, respectively, and a means for calculating the detected value of the primary current of the induction motor by each axis component 11y+i of the γ-δ coordinate.
1d, and γ of the current primary voltage based on i1γ* and the target value i1δ* of the δ-axis component of the −blow mold flow and 117+i1d from the second coordinate transformation unit. means for calculating a variation Δv1δly from v1γ* in the axis component and a variation ΔvB from v1δ* in the δ-axis component of the current primary voltage; 1 1d** I IQ*+ ily*+ λ2
d*, −Blow mold source angular frequency ω0, excitation inductance set value M* and Δv1δl, a secondary resistance change calculation unit that calculates a change with respect to the set value of the secondary resistance, and a motor speed detection signal. A speed change detection section is provided to detect the presence or absence of speed change based on v1? * and Δv1δI7
Let the added value be the target value v1γ of the γ-axis component of the primary voltage,
Also, the sum of ■1δ* and Δv1δI6 is the primary voltage δ
The target value of the axis component is v16, and these target values v17rVl
+I, and control the power supply voltage based on the slip angular frequency calculation unit, and calculate the current secondary time constant based on the set value of the secondary time constant and the calculation result obtained by the secondary resistance change calculation unit. Find the constant, and calculate this quadratic time constant, i
Calculations are performed using 1q*, λ, and */M*, and when the speed change detection section detects that there is a speed change,
The calculation result of the secondary resistance change calculation section before the occurrence of the speed change is held, and the calculation of the calculation section is stopped, and when the speed change detection section detects no speed change, the calculation of the calculation section is resumed. I try to force myself to do so.

Furthermore, in the present invention, instead of using the secondary resistance change calculation section, the deviation between the variation Δv1δl from v1δ* in the δ-axis component of the current primary voltage and the target value zero of this Δv1δB is input, and the slip angle Slip angle frequency control amplifier (
A voltage fluctuation control amplifier) is provided, and Δω■ from this slip angle frequency control amplifier (voltage fluctuation control amplifier) and ω■* obtained by the Veri angular frequency calculation section
The same operation and effect can be obtained by using the added value of the slip angular frequency as the target value of the slip angular frequency.

In this case, when the speed change detection section detects the presence of a speed change, it holds the output Δω■ of the voltage fluctuation control amplifier before the speed change occurs, and stops the calculation of the voltage fluctuation control amplifier, and detects the speed change. When the section detects that there is no change in speed, it restarts the calculation of the voltage fluctuation control amplifier. Alternatively, when the speed change detection section detects a speed change, calculate the secondary resistance change K based on the output Δω■ of the voltage fluctuation control amplifier and the slip angular frequency ω before the speed change occurs; After setting and changing the secondary resistance target value R2* of the slip angular frequency calculation section using the secondary resistance change K, the calculation of the voltage fluctuation control amplifier was stopped, and the speed change detection section detected no speed change. If so, the calculation of the voltage fluctuation control amplifier is restarted.

Furthermore, in the present invention, during no-load operation, a change in the primary resistance setting value is calculated based on Δv1δly, primary resistance setting values R1* and i1d*, and Δv16, M
*, secondary self-inductance L2*, ω. and λ2d*
It is also possible to provide an identification circuit section that calculates a change in excitation inductance with respect to a set value based on .

F. Embodiment FIG. 1(A) is a circuit diagram showing an embodiment of the present invention, and the same symbols as in FIG. 8 indicate the same parts. 11 is λ2, * according to the angular frequency ωr from the speed detection unit 43.
It is a secondary magnetic flux command amplifier that outputs /M*, and ωr
λ2d until exceeds a certain value. Output */M* and ω
When r exceeds a certain value and enters the field control region, λ2 a * / M * becomes smaller according to ωr. 1□ is (7)
This is an arithmetic unit that executes the calculation of the formula, λ, */M*(1+L2*/R2*·S).

5 is a first coordinate transformation unit, i1d*, i1γ*
It has a function to calculate i1d* in the γ-δ coordinate with the primary current 11 as the reference axis based on +
d*)=ψ, 557 "Execute the operation d-=1°.

5□ is an ideal voltage calculation unit for calculating the target value of the primary voltage, and the sin
(19
) and calculates v1a* and V1d*.

6 is a second coordinate transformation unit, - the detected value i1d of the blow mold flow;
i, is converted into each axis component 11a, i1δ of the γ-δ coordinate. These j Iy+ iII+ are respectively target values i1d*
, ila* (=O), and their deviations are input to the PI amplifiers 7.8, which are current control amplifiers. P
From I amplifier 7.8, Δv17. Δv1δ1δ is output, and as described above, Δv1δ1a is added to V1a*, and Δv1δllll is added to v1δ*, respectively. 9 is a polar coordinate conversion part, - the magnitude of the blow mold pressure vector V1 is 1;
Output the phase angle φ between v11 and the γ axis (see Figure 3)
. This phase angle φ is added to ψ and θ (=ω.t), which will be described later, and these added values and 1v11 are manually input to the PWM circuit 4□ and converted into the primary voltage command value corresponding to the U and VSW phases. , whereby the voltage of the inverter 4□ is controlled.

10 is a secondary resistance change calculating section, λ7γ*/M*,
i 1d*, i IQ*+ ωQ, i
It* and Δv1δl.

This is the part that calculates the secondary resistance change K by taking in the equation (45) and calculating the equation (45). Reference numeral 11 denotes a slip angular frequency calculation unit, which has a function of taking in K, λ2dl*/M*, and IIQ* and executing equation (52) to obtain ω. By the way, when a computer executes calculations for each part of the circuit shown in FIG. 1(A), ω■ is calculated as follows. That is, a series of calculations including the calculation of K and the calculation of the slip angular frequency are instantaneously performed by a clock signal, and the secondary resistance value obtained in the (n-1)th calculation in the slip angular frequency calculation section 11 is calculated for the nth calculation. Set value in calculation.

K and R2 obtained in the nth operation are respectively K n + R
2m and assigning a preset value R2* to the initial value R20 of R2fi, the first to nth calculations are as follows.

1st time R2+=(1+Kl)・R2゜=(+ to 1+)
・R2*22+ R22"" (1+ to 2) ・R21=(
1+ R2)・(+ to 1+)・R2*n2+ R2−=
(to 1+) ・R2+, -+>=(to 1,000, X1+
−+)...(+ to 1+)・R2* Therefore, if ω, calculated by the nth operation, is expressed as ω1d, ω and i become the following equation (53), and ω1d=(+ to 1+)・ω,. -1,...(53) Remember ω5(n-1) obtained from the (n-1)th operation, and (
53) By using Kn obtained by formula, ω.

is required.

In this case, the initial value ω, 1 is ω, I = (1 + KI) φR2*・l / L 2
*・i1d*/(λ2d*/M*).

The thus obtained ω and the rotor angular frequency detection value ω7 of the electric motor IM are added to obtain the added value ω. Let be the target value of the power angular frequency.

12 is an identification circuit section, and Δv1δly during no-load operation.
, and 11d*, and execute the upper equation of equation (50) to calculate the change A1 in the primary resistance, thereby identifying the primary resistance, and Δv1δ1δ, ω.

and λ2d*/M*, and execute the lower part of equation (50) to calculate the change in excitation inductance A1,
This has the function of identifying the excitation inductance M2/L2. Here, the timing of determining whether or not there is no-load operation and driving the identification circuit section 12 is determined by the comparator 13.
This is done by When the rated torque current is 100%, the comparator 13 sets a value of 5% of the rated torque current as a set value, and compares it with the value of i1d*. If i1d* is lower than the set value, it is determined to be no-load operation and identified. In addition to driving the circuit 12, since the influence of the secondary resistance change does not appear in this case, the output signal thereof causes the secondary resistance change calculation unit 1o to stop.

Reference numeral 21 denotes a speed change detection section that detects the presence or absence of a speed change of the electric motor based on the detection signal of the speed detection section 43. When the speed change detection unit 21 detects a speed change,
The calculation result of the secondary resistance change calculation section 1o before the occurrence of the speed change is held, and the calculation of the calculation section 10 is stopped, and when no speed change is detected, the calculation of the calculation section 1o is restarted. This makes it possible to maintain good acceleration/deceleration characteristics when the motor speed changes.

In the above, in order to perform the calculation of equation (20) in consideration of the P term when calculating vl, * in the calculation unit 52,
1d* from R1* (1+Lσ/R
, *P), a more accurate ideal voltage can be provided and the current response can be improved.

Next, a description will be given of an embodiment that is an improvement on the embodiment shown in FIG. 1(A).

From equation (16), if we ignore the change in secondary magnetic flux, we get the following (16
a) Equation is obtained. However, λ2,2 λ2d is (18
) is used to represent λ2d.

(Left below) As can be seen from this equation, when the primary current suddenly changes, only the value corresponding to the rate of change over time is vl? + VI 6
will change. In other words, the change in Vla includes the temporal change rate of the primary current in addition to the change in secondary resistance, and the change in Vly includes the change in primary resistance and excitation inductance, as well as the change in primary current. Similarly, the temporal rate of change of the primary current will be included.

Therefore, in the embodiment shown in FIG. 1(A), when the blowing mold flow suddenly changes, the change is taken as a secondary resistance change, and also as a primary resistance change and an excitation inductance change, and is used for compensation. Less accurate.

Therefore, in the embodiment shown in FIG. 1(B), L a P l l
t.

The primary voltage fluctuation including the terms L and Pila (this is expressed as Δv
1δl? + Δvl) and the primary voltage fluctuation not included (this is defined as Δvlyl + Δv161), and the former value Δv12dΔvl is used to control the primary voltage, and the latter value Δv1δ 1 , 1
．． Δv1δ ljl is used to compensate for changes in secondary resistance and to identify primary resistance and the like.

Specifically, as shown in FIG. 1(B), for the PI amplifier 7, it corresponds to L e P lly (i1d*1
+y)XLヮ/T, proportional element 7I and (t
1d*i+? ), and outputs the sum of the proportional term output from the proportional element 7□ and the integral term output from the integral element 72 as Δv1δly, and outputs the integral term output as Δv1a, It is configured as follows. Regarding the PI amplifier 8, (i 1d* −i +a) xL, /T corresponds to L, Pila.

The sum of the proportional term output from the proportional element 8I and the integral term output from the integral element 8 is calculated as Δv.
It is configured to output the integral term output from the integral element 8□ as Δv1δ 161. However, T indicates the calculation period, (i Iy* −
i 1d) /T, and (i IIl* i +a)
/Ts is calculated using a differential element.

With this configuration, even when the primary current suddenly changes, Δ
v1δ 1 v 1. Since this effect does not appear on Δv1δ IJI, accurate secondary resistance compensation and -blow mold pressure identification can be performed.

FIG. 2 is a circuit diagram showing another embodiment of the present invention, in which a PI amplifier 14 which is a voltage fluctuation control amplifier is used instead of using the secondary resistance change calculation section 10.
By inputting the deviation between Δvl and the target value zero of Δv1δ16, the variation Δω■ from the target value ω■* at the current slip angular frequency is obtained as an output signal. Then, the slip angular frequency calculating section 15 calculates ω■* based on a formula assuming that R2 does not vary from the ideal value, and calculates ω■* and Δω.
The target value of the slip angular frequency is the sum of (2) and (3).

According to such an embodiment, the target value of the slip angular frequency is automatically corrected according to the change in the secondary resistance.

Note that 16 is a comparator 13 or a speed change detection section 21
This is a switch section for disabling the output of the PI amplifier 14 by the output signal of the PI amplifier 14.

In the configuration shown in FIG. 2, when the speed of the motor changes and the speed change detection unit 21 detects a change in speed, first, the calculation of the PI amplifier 14 is temporarily stopped and the value up to that point is held. Then, when the speed change of the electric motor disappears, the PI
The stoppage of the computation of the amplifier 14 is canceled and each computation is executed again.

Or, based on the slip frequency ω before the motor speed change and the slip compensation amount ΔωS, calculate the secondary resistance change as follows (5
4) Calculate from the formula and change the secondary resistance setting value R2* of the slip angular frequency calculation section 15.

l+Kn=ω, /ω■* ・・・・・・・・・(54
) However, ω■=ω■*+Δω■, and Kfi is the secondary resistance change.

The secondary resistance setting value R2* is changed as follows.

R2, *= (to 1+) ・R2, -, *----
・(55) Tatami, R2-1*= (1+Kl)
(2 to 1+)... (-+ to 1+) ・R2*
, K, ~ is the secondary resistance change at each time,
R2* is the initial secondary resistance setting value A.

Further, in the embodiment shown in FIG. 2, the PI amplifier 7.8 shown in FIG. 1(B) is used as the PI amplifier 7.8,
While manually inputting Δv1,1 to the identification circuit section 12, Δv1
By inputting the deviation between δ* and Δv1δ1d+ to the PI amplifier 14, it is possible to accurately compensate for the secondary resistance change, etc., as described above.

G0 Effect of the invention According to the invention, the rotational coordinate γ with the primary voltage fluctuation as the reference axis
The δ-axis component v16 of the primary voltage on the -δ axis is the primary resistance R,
Therefore, regarding the primary voltage fluctuation caused by the change in the secondary resistance, the fluctuation component Δv1δ1d does not include the influence of the primary resistance. Since the secondary resistance change is compensated for when determining the target value of the slip angular frequency using Moreover, the ideal value of blowing mold pressure vl y *
, V 1δ*, excitation command λ2 a * / M *
Since the excitation current i1d* and the excitation current i1d* are not treated as equal and are calculated separately, this vector control is also effective for applications where field control is performed. Furthermore, Δv1a, Δv1δ
Since voltage control is performed by determining 16, it is possible to perform voltage correction for changes in primary resistance and secondary resistance, thereby achieving highly effective torque control accuracy and improving torque response.

When compared with the circuit in Figure 8, the circuit in Figure 8 performs voltage control only on the d-q coordinates, and Δv1δi
Since 1dΔv1δ1q includes fluctuations due to changes in both primary resistance and secondary resistance, Δv1δ1δ,
Although it is necessary to separate data from △VIQ into data that is affected only by secondary resistance changes and data that is affected by both changes, in the present invention, ΔVIQ is
v17. It can be directly controlled by ΔvIγ and i1δ.

Also Δv1. By performing secondary resistance compensation, Δv1δly
Since only the influence of the primary resistance change remains, this Δv
It is also possible to estimate the primary resistance change based on 1δly.

Furthermore, in the present invention, the primary voltage during no-load operation is analyzed, and the change with respect to the set value of the primary resistance is calculated based on Δv17 (=Δv1δid) by paying attention to the analysis result, and Δv
Since the change in excitation inductance M2/L2 is calculated based on l, it is possible to compensate for the primary resistance and excitation inductance.

In addition, by changing the configuration of the current control amplifier, Pi1γ2L aP
If the voltage deviation corresponding to i1γ, i1δ is obtained as the proportional term output, and the voltage fluctuation generated due to the secondary resistance change is obtained as the integral term output, L aP lly, L eP lla when the primary current changes. The term no longer appears in the integral term output. This improves the current response and also increases the integral term output Δv1δlvl+ Δv1
Using δ 161, it became possible to accurately compensate for the primary resistance, secondary resistance, and excitation inductance.

Furthermore, when the motor speed is changing, the secondary resistance fluctuation compensation calculation is stopped and the data of the secondary resistance change up to that point is held, thereby making it possible to maintain good acceleration/deceleration characteristics.

When there is no change in motor speed, stable secondary resistance compensation becomes possible by restarting the computation of secondary resistance fluctuation compensation.

[Brief explanation of drawings]

FIG. 1(A) is a block circuit diagram showing an embodiment of the present invention;
FIG. 1(B) is a block diagram showing another embodiment of the present invention, FIG. 2 is a block diagram showing still another embodiment of the present invention, FIG. 3 is an equivalent circuit diagram of an induction motor, and FIG. 7 to 7 are vector diagrams of current, voltage, etc., respectively, and FIG. 8 is a block circuit diagram showing a comparative example of a vector control device. 1□... Secondary magnetic flux command amplifier, 12... Arithmetic unit, 2
...Speed amplifier, 5□...First coordinate conversion section, 5□
...Ideal voltage calculation section 1δ...Second coordinate transformation section, 7
, 8... PI amplifier which is a current control amplifier, 10...
- Secondary resistance change calculation unit, i1d15...Slip angle frequency calculation unit, 12...Identification circuit unit, 14...Voltage fluctuation division, control amplifier, 21...Speed change detection unit. Figure 3 Figure 4 Figure 6 C Figure 7 1γ

Claims (8)

[Claims] (1) Rotating coordinates that rotate in synchronization with the power supply angular frequency of the induction motor, and the coordinates with the secondary magnetic flux as the reference axis are d-q
As coordinates, the d-axis component and q of the primary current of the induction motor
Vector control of an induction motor, which includes means for calculating target values i_1_d* and i_1_q* of shaft components, respectively, and a slip angular frequency calculation unit that calculates a slip angular frequency based on an arithmetic expression including a set value of a secondary time constant. In the device, the means for calculating i_1_d* calculates the target value λ_2_d of the d-axis component of the secondary magnetic flux according to the rotor angular frequency of the induction motor.
*, and means to calculate i_1_d* based on this λ_2_d* and a differential term, and the phase ψ with respect to the d-q axis is tan^-^1 (i_1_q*/i_1
_d*) and the coordinates with the primary current I_1 as the reference axis are the γ-δ coordinates, then the target value of the γ-axis component of the primary current i_1_γ*(=
I_1) and a first coordinate transformation unit that calculates the phase ψ; and a ratio λ_2_d between λ_2_d* and the excitation inductance M;
*/M, a means for calculating target values v_1_γ*, V_1_δ* of the γ- and δ-axis components of the primary voltage based on the calculation results of the first coordinate conversion unit and the command value ω_0 of the power source angular frequency, respectively; a second coordinate conversion unit that converts the detected value of the primary current into each axis component i_1_γ, i_1_δ of the γ-δ coordinate; and i_1_γ* and a target value i_1_ of the δ-axis component of the primary current.
δ* and i_1_γ, i_1 from the second coordinate transformation unit
Based on
_1_δ; and i_1_d*, i_1_q*, i_1_γ*, λ_2_.
d*, the primary power supply angular frequency ω_0, the set value M* of the excitation inductance, and the set value of the secondary resistance Δv_1_δ, and a secondary resistance change calculation unit that calculates the change with respect to the set value of the secondary resistance, based on the speed detection signal of the motor. , a speed change detection unit that detects the presence or absence of a speed change, and calculates the sum of v_1_γ* and Δv_1_γ as γ of the primary voltage.
The target value of the axis component is v_1_γ, and v_1_δ* and Δ
The added value with _1_δ is the target value v_ of the δ-axis component of the primary voltage.
1_δ, and the power supply voltage is controlled based on these target values v_1_γ and v_1_δ, and the slip angular frequency calculation unit uses the set value of the secondary time constant and the calculation result obtained by the secondary resistance change calculation unit. Find the second-order time constant at that time based on this second-order time constant, i_1
Calculation is performed using _q* and λ_2_d*/M*, and when the speed change detection section detects that there is a speed change,
The calculation result of the secondary resistance change calculation section before the occurrence of the speed change is held, and the calculation of the calculation section is stopped, and when the speed change detection section detects no speed change, the calculation of the calculation section is resumed. A vector control device for an induction motor. (2) Rotating coordinates that rotate in synchronization with the power supply angular frequency of the induction motor, and the coordinates with the secondary magnetic flux as the reference axis are d-q
As coordinates, the d-axis component and q of the primary current of the induction motor
Vector control of an induction motor, which includes means for calculating target values i_1_d* and i_1_q* of shaft components, respectively, and a slip angular frequency calculation unit that calculates a slip angular frequency based on an arithmetic expression including a set value of a secondary time constant. In the device, the means for calculating i_1_d* calculates the target value λ_2_d of the d-axis component of the secondary magnetic flux according to the rotor angular frequency of the induction motor.
*, and means to calculate i_1_d* based on this λ_2_d* and a differential term, and the phase ψ with respect to the d-q axis is tan^-^1 (i_1_q*/i_1
_d*) and the coordinates with the primary current I_1 as the reference axis are the γ-δ coordinates, then the target value of the γ-axis component of the primary current i_1_γ*(=
I_1) and a first coordinate transformation unit that calculates the phase ψ; and a ratio λ_2_d between λ_2_d* and the excitation inductance M;
*/M, a means for calculating target values v_1_γ* and v_1_δ* of the γ and δ axis components of the primary voltage based on the calculation result of the first coordinate conversion unit and the command value ω_0 of the power supply angular frequency, respectively, and a second coordinate conversion unit that converts the detected value of the primary current into each axis component i_1_γ, i_1_δ of the γ-δ coordinate; and i_1_γ* and a target value i_1_ of the δ-axis component of the primary current.
δ* and i_1_γ, i_1 from the second coordinate transformation unit
Based on
means for calculating _1_δ; inputting the deviation between the variation Δv_1_δ from v_1_δ* in the δ-axis component of the current primary voltage and the target value zero of this Δv_1_δ; and a means for calculating the target value ω, * of the slip angular frequency.
A voltage variation control amplifier that outputs a variation Δω_■ from the voltage variation control amplifier, and a speed change detection section that detects the presence or absence of a speed change based on a speed detection signal of the motor are provided, and the voltage variation control amplifier outputs a variation Δω_■ The added value of v_1_γ* and ω_■* calculated by the slip angular frequency calculating section is the target value of the slip angular frequency, and the added value of v_1_γ* and Δv_1_γ is the primary voltage γ.
The target value of the axis component is v_1_γ, and v_1δ* and Δ_
1_δ and the target value v_1 of the δ-axis component of the primary voltage.
_δ, and control the power supply voltage based on these target values v_1_γ and v_1_δ, and when the speed change detection section detects that there is a speed change,
Output of control amplifier Δω＿■ for voltage fluctuation before speed change occurs
vector control of an induction motor, characterized in that the operation of the voltage fluctuation control amplifier is stopped while the voltage fluctuation control amplifier is held, and the calculation of the voltage fluctuation control amplifier is restarted when the speed change detection section detects no speed change. Device. (3) Rotating coordinates that rotate in synchronization with the power supply angular frequency of the induction motor, and the coordinates with the secondary magnetic flux as the reference axis are d-q.
As coordinates, the d-axis component and q of the primary current of the induction motor
Vector control of an induction motor, which includes means for calculating target values i_1_d* and i_1_q* of shaft components, respectively, and a slip angular frequency calculation unit that calculates a slip angular frequency based on an arithmetic expression including a set value of a secondary time constant. In the device, the means for calculating i_1_d* calculates the target value λ_2_d of the d-axis component of the secondary magnetic flux according to the rotor angular frequency of the induction motor.
*, and means to calculate i_1_d* based on this λ_2_d* and a differential term, and the phase ψ with respect to the d-q axis is tan^-^1 (i_1_q*/i_1
_d*) and the coordinates with the primary current I_1 as the reference axis are the γ-δ coordinates, then the target value of the γ-axis component of the primary current i_1_γ*(=
I_1) and a first coordinate transformation unit that calculates the phase ψ; and a ratio λ_2_d between λ_2_d* and the excitation inductance M;
*/M, a means for calculating target values v_1_γ* and v_1_δ* of the γ and δ axis components of the primary voltage based on the calculation result of the first coordinate conversion unit and the command value ω_0 of the power supply angular frequency, respectively, and a second coordinate conversion unit that converts the detected value of the primary current into each axis component i_1_γ, i_1_δ of the γ-δ coordinate; and i_1_γ* and a target value i_1_ of the δ-axis component of the primary current.
δ* and i_1_γ, i_1 from the second coordinate transformation unit
Based on
means for calculating _1_δ, inputting the deviation between the variation Δv_1_δ from v_1_δ* in the δ-axis component of the current primary voltage and the target value zero of this Δv_1_δ, and calculating the target value ω_■ of the slip angular frequency.
A voltage variation control amplifier that outputs a variation Δω_■ from *, and a speed change detection section that detects the presence or absence of a speed change based on a speed detection signal of the motor are provided, and Δω_ from the voltage variation control amplifier is provided. The added value of ■ and ω_■* calculated by the slip angular frequency calculation section is set as the target value of the slip angular frequency, and the added value of v_1_γ* and Δv_1_γ is set as the primary voltage γ.
The target value of the axis component is v_1_γ, and v_1_δ* and Δ
The added value with _1_δ is the target value v_ of the δ-axis component of the primary voltage.
1_δ, and control the power supply voltage based on these target values v_1_γ and v_1_δ, and when the speed change detection section detects that there is a speed change,
Output of control amplifier Δω＿■ for voltage fluctuation before speed change occurs
The secondary resistance change K is calculated based on the slip angular frequency ω_■, and the secondary resistance target value R_2* of the slip angular frequency calculating section is changed using the secondary resistance change K, and then voltage fluctuation control is performed. A vector control device for an induction motor, characterized in that the operation of the amplifier is stopped, and when the speed change detection section detects no change in speed, the operation of the voltage fluctuation control amplifier is restarted. (4) During no-load operation, calculate the change in the primary resistance setting value based on Δv_1_γ, the primary resistance setting values R_1* and i_1_d*, and calculate Δv_1_, M*,
Secondary self-inductance L_2*, ω_0 and λ_2_
The induction motor vector according to claim (1), claim (2), or claim (3), further comprising an identification circuit unit that calculates a change in excitation inductance with respect to a set value based on d*. Control device. (5) Rotating coordinates that rotate in synchronization with the power supply angular frequency of the induction motor, and the coordinates with the secondary magnetic flux as the reference axis are d-q.
As coordinates, the d-axis component and q of the primary current of the induction motor
Vector control of an induction motor, which includes means for calculating target values i_1_d* and i_1_q* of shaft components, respectively, and a slip angular frequency calculation unit that calculates a slip angular frequency based on an arithmetic expression including a set value of a secondary time constant. In the device, the means for calculating i_1_d* calculates the target value λ_2_d of the d-axis component of the secondary magnetic flux according to the rotor angular frequency of the induction motor.
*, and means to calculate i_1_d* based on this λ_2_d* and a differential term, and the phase ψ with respect to the d-q axis is tan^-^1 (i_1_q*/i_1
_d*) and the coordinates with the primary current I_1 as the reference axis are the γ-δ coordinates, then the target value of the γ-axis component of the primary current i_1_γ*(=
I_1) and a first coordinate transformation unit that calculates the phase ψ; and a ratio λ_2_d between λ_2_d* and the excitation inductance M;
*/M, a means for calculating target values v_1_γ* and v_1_δ* of the γ and δ axis components of the primary voltage based on the calculation result of the first coordinate conversion unit and the command value ω_0 of the power supply angular frequency, respectively, and a second coordinate conversion unit that converts the detected value of the primary current into each axis component i_1_γ, i_1_δ of the γ-δ coordinate; and a target value i_1_δ* of the δ-axis component of the primary current and i_1_δ from the second coordinate conversion unit. a proportional element that calculates the temporal change rate of the current deviation between the current deviation and the leakage inductance L_δ and outputs the proportional term output as a product of this and the leakage inductance L_δ, and an integral element that outputs the integrated value of the current deviation as the integral term output, a current control amplifier that outputs the sum of the proportional term output and the integral term output as a voltage variation Δv_1_δ from v_1_δ* in the δ-axis component of the current primary voltage, and outputs the integral term output as Δv_1_δ_1; and i_1_γ from the second coordinate transformation unit, the variation Δ from v_1_γ* in the γ-axis component of the current primary voltage
means for calculating v_1_γ, i_1_d*, i_1_
q*, i_1_γ*, λ_2_d*, primary power supply angular frequency ω_0, excitation inductance setting value M* and Δv_1
A secondary resistance change calculation unit that calculates a change in the secondary resistance with respect to a set value based on _δ_1 and a speed change detection unit that detects the presence or absence of a speed change based on a speed detection signal of the motor are provided, and v_1_γ* The sum of Δv_1_γ and Δv_1_γ is the primary voltage γ
The target value of the axis component is v_1_γ, and v_1_δ* and Δ
The added value with _1_δ is the target value v_ of the δ-axis component of the primary voltage.
1_δ, and the power supply voltage is controlled based on these target values v_1_γ and v_1_δ, and the slip angular frequency calculation unit uses the set value of the secondary time constant and the calculation result obtained by the secondary resistance change calculation unit. Find the second-order time constant at that time based on this second-order time constant, i_1
Calculation is performed using _q* and λ_2_d*/M*, and when the speed change detection section detects that there is a speed change,
The calculation result of the secondary resistance change calculation section before the occurrence of the speed change is held, and the calculation of the calculation section is stopped, and when the speed change detection section detects no speed change, the calculation of the calculation section is resumed. A vector control device for an induction motor. (6) Rotating coordinates that rotate in synchronization with the power supply angular frequency of the induction motor, and the coordinates with the secondary magnetic flux as the reference axis are d-q.
As coordinates, the d-axis component and q of the primary current of the induction motor
Vector control of an induction motor, which includes means for calculating target values i_1_d* and i_1_q* of shaft components, respectively, and a slip angular frequency calculation unit that calculates a slip angular frequency based on an arithmetic expression including a set value of a secondary time constant. In the device, the means for calculating i_1_d* calculates the target value λ_2_d of the d-axis component of the secondary magnetic flux according to the rotor angular frequency of the induction motor.
*, and means to calculate i_1_d* based on this λ_2_d* and a differential term, and the phase ψ with respect to the d-q axis is tan^-^1 (i_1_q*/i_1
_d*) and the coordinates with the primary current I_1 as the reference axis are the γ-δ coordinates, then the target value of the γ-axis component of the primary current i_1_γ*(=
I_1) and a first coordinate transformation unit that calculates the phase ψ; and a ratio λ_2_d between λ_2_d* and the excitation inductance M;
*/M, a means for calculating target values v_1_γ* and v_1_δ* of the γ and δ axis components of the primary voltage based on the calculation result of the first coordinate conversion unit and the command value ω_0 of the power supply angular frequency, respectively, and a second coordinate conversion unit that converts the detected value of the primary current into each axis component i_1_γ, i_I_δ of the γ-δ coordinate; and a target value i_1_δ* of the δ-axis component of the primary current and i_1_δ from the second coordinate conversion unit. a proportional element that calculates the temporal rate of change of the current deviation between the current deviation and the leakage inductance L_■ and outputs the proportional term output, and an integral element that outputs the integrated value of the current deviation as the integral term output, a current control amplifier that outputs the sum of the proportional term output and the integral term output as a voltage variation Δv_1_δ from v_1_δ* in the δ-axis component of the current primary voltage, and outputs the integral term output as Δv_1_δ_1; * and i_1_γ from the second coordinate transformation unit, the variation Δ from v_1_γ* in the γ-axis component of the current primary voltage
means for calculating v_1_γ, and a voltage fluctuation device that inputs the deviation between the integral term output Δv_1_δ_1 of the current control amplifier and the target value zero of this Δv_1_δ_1, and outputs the fluctuation amount Δω_■ from the target value ω_■* of the slip angular frequency. A minute control amplifier and a speed change detection section that detects the presence or absence of a speed change based on the speed detection signal of the motor are provided, and Δω_■ from the voltage variation control amplifier and ω_■ obtained by the slip angular frequency calculation section are provided. *The added value of v_1_γ* and Δv_1_γ is the target value of the slip angular frequency, and the added value of v_1_γ* and Δv_1_γ is the primary voltage γ.
The target value of the axis component is v_1_γ, and v_1_δ* and Δ
The added value with _1_δ is the target value v_ of the δ-axis component of the primary voltage.
1_δ, and control the power supply voltage based on these target values v_1_γ and v_1_δ, and when the speed change detection section detects that there is a speed change,
Output of control amplifier Δω＿■ for voltage fluctuation before speed change occurs
vector control of an induction motor, characterized in that the operation of the voltage fluctuation control amplifier is stopped while the voltage fluctuation control amplifier is held, and the calculation of the voltage fluctuation control amplifier is restarted when the speed change detection section detects no speed change. Device. (7) Rotating coordinates that rotate in synchronization with the power supply angular frequency of the induction motor, and the coordinates with the secondary magnetic flux as the reference axis are d-q.
As coordinates, the d-axis component and q of the primary current of the induction motor
Vector control of an induction motor, which includes means for calculating target values i_1_d* and i_1_q* of shaft components, respectively, and a slip angular frequency calculation unit that calculates a slip angular frequency based on an arithmetic expression including a set value of a secondary time constant. In the device, the means for calculating i_1_d* calculates the target value λ_2_d of the d-axis component of the secondary magnetic flux according to the rotor angular frequency of the induction motor.
*, and means to calculate i_1_d* based on this λ_2_d* and a differential term, and the phase ψ with respect to the d-q axis is tan^-^1 (i_1_q*/i_1
_d*) and the coordinates with the primary current I_1 as the reference axis are the γ-δ coordinates, then the target value of the γ-axis component of the primary current i_1_γ*(=
I_1) and a first coordinate transformation unit that calculates the phase ψ; and a ratio λ_2_d between λ_2_d* and the excitation inductance M;
*/M, a means for calculating target values v_1_γ* and v_1_δ* of the γ and δ axis components of the primary voltage based on the calculation result of the first coordinate conversion unit and the command value ω_0 of the power supply angular frequency, respectively, and a second coordinate conversion unit that converts the detected value of the primary current into each axis component i_1_γ, i_1_δ of the γ-δ coordinate; and a target value i_1_δ* of the δ-axis component of the primary current and i_1_δ from the second coordinate conversion unit. a proportional element that calculates the temporal rate of change of the current deviation between the current deviation and the leakage inductance L_■ and outputs the proportional term output, and an integral element that outputs the integrated value of the current deviation as the integral term output, a current control amplifier that outputs the sum of the proportional term output and the integral term output as a voltage variation Δv_1_δ from v_1_δ* in the δ-axis component of the current primary voltage, and outputs the integral term output as Δv_1_δ_1; * and i_1_γ from the second coordinate transformation unit, the variation Δ from v_1_γ* in the γ-axis component of the current primary voltage
means for calculating v_1_γ, and a voltage fluctuation device that inputs the deviation between the integral term output Δv_1_δ_1 of the current control amplifier and the target value zero of this Δv_1_δ_1, and outputs the fluctuation amount Δω_■ from the target value ω_■* of the slip angular frequency. A minute control amplifier and a speed change detection section that detects the presence or absence of a speed change based on the speed detection signal of the motor are provided, and Δω_■ from the voltage variation control amplifier and ω_■ obtained by the slip angular frequency calculation section are provided. The added value of v_1_1_γ* and Δv_1_1_γ is taken as the target value of the slip angular frequency, the added value of v_1_1_γ* and Δv_1_1_γ is taken as the target value of the γ-axis component of the primary voltage v_1_1_γ, and v_
The added value of 1_δ* and Δ_1_δ is the target value v_1_δ of the δ-axis component of the primary voltage, and these target values v_1_γ, v
The power supply voltage is controlled based on _1_δ, and when the speed change detection section detects that there is a speed change,
Output of control amplifier Δω＿■ for voltage fluctuation before speed change occurs
The secondary resistance change K is calculated based on the slip angular frequency ω_■, and the secondary resistance target value R_2* of the slip angular frequency calculating section is changed using the secondary resistance change K, and then voltage fluctuation control is performed. A vector control device for an induction motor, characterized in that the operation of the amplifier is stopped, and when the speed change detection section detects no change in speed, the operation of the voltage fluctuation control amplifier is restarted. (8) The means for calculating Δv_1_γ calculates the time rate of change of the current deviation between i_1_γ* and i_1_γ from the second coordinate transformation unit, and calculates the rate of change in current deviation between this and the leakage inductance L_
It includes a proportional element whose proportional term output is the product of Voltage variation Δ from v_1_γ* in the γ-axis component of voltage
At the same time, output the integral term output as Δ
It consists of a current control amplifier that outputs Δv_1_γ_1 and the primary resistance setting value R during no-load operation.
Based on _1* and i_1_d*, calculate the change with respect to the set value of the primary resistance, and calculate Δv_1_δ, M*,
Secondary self-inductance L_2*, ω_0 and λ_2_
The induction motor vector according to claim (5), claim (6), or claim (7), further comprising an identification circuit unit that calculates a change in excitation inductance with respect to a set value based on d*. Control device.