JPS6244088A - Controller of induction motor - Google Patents

Abstract

PURPOSE:To compensate a variation in the temperature of the secondary winding time constant of a motor by detecting interlinked magnetic flux of q<e> axis secondary winding, and correcting a slip frequency and the secondary winding time constant, thereby compensating the delay of a controller. CONSTITUTION:A rotary coordinates converter 16 converts an output voltage detected by a search coil wound in the primary winding to voltages vd<e>c, vg<e>c of rotary coordinates. The calculator 17 of secondary interlinked magnetic flux equivalent calculates the secondary interlinked magnetic flux equivalent lambda'g<e>r by the voltages vd<e>c, vg<e>c and the primary winding currents id<e>s, ig<e>g. The secondary winding resistance setter 18 controls the time constant set value of the secondary winding used for calculating in the secondary magnetic flux slip frequency calculator 12 by the equivalent lambda'g<e>r, torque current ig<e>r and synchronizing angle frequency command omega to coincide with the time constant value of the secondary winding of an induction motor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an induction motor that is capable of stably controlling torque even when internal constants of the induction motor change.

[Conventional technology]

A conventional device of this type is shown in FIG. The figure is a block diagram of a vector control induction motor. In the figure, 1 is a three-phase spinning motor, and 2 is a three-phase induction motor.
3 is a variable voltage variable frequency power converter that supplies three-phase father current power to the induction motor; 4 is a rectangular coordinate axis (df"-) that rotates at an electrical angular velocity ω;
t pressure conversion circuit that converts the voltage I'deg and Vq'l seen on the qe axis) to three-phase alternating current; 5 is a three-phase alternating current 1
ur ly + 1wk Convert onto d'-q0 axis and t
A current coordinate conversion circuit that obtains currents 1qea and 1dei, 6 is due to leakage reactance. 113- A non-interference compensation circuit that compensates for interference to the q13 axis, 7 is an excitation current (ld
e+1) control circuit, 8 is magnetic flux (λd” r ) 1tl
lJ Both circuits, 8 is a field weakening setting circuit that changes the secondary magnetic flux command (λ (1er) depending on the speed for field weakening setting, 10 is a torque component current (iqe,) control circuit, 11
is the rotational angular velocity (scream) control circuit. In addition, 12 is a secondary magnetic flux (λder) frequency (ω8) calculation circuit;
3 is an integrator that integrates the angular velocity ω and calculates the phase θ, 14 is a sine and cosine generator that calculates the value of sin θ and c0817, which are necessary for coordinate transformation, and 15 is a coefficient that multiplies the rotational angular velocity ω1 by the polar logarithm pt. It is a vessel.

Next, the operation will be explained. First, in FIG. 6, the vector pω8 is determined by the following equation (1) in the secondary magnetic flux vector frequency calculation circuit 12A.

Therefore, the electrical angular velocity ω is controlled by tl 6-q At this time, among the e-axis and secondary winding flux linkage λder, λ, er, the qe-axis secondary winding green flux linkage λ, e7 is focused to zero. However, the direction of the secondary flux linkage coincides with the df axis. At this time, the state equation of motive 1 using three-phase induction is shown by equation (3).

However, P: differential operator R, knee winding resistance Rr: secondary winding resistance σ: leakage coefficient, knee winding self-inductance Lr: secondary winding self-inductance M knee, secondary winding Mutual inductance Vd's:
d'-axis primary voltage vq@, ', q e-axis primary voltage Here, input variable ''' a + 'Iq (I g
When controlled by equations (4) and (5), Vd”s = vaes −ωσLa1q's
"・"・(4) vqes = vqes + ωσL
s (idea−λ(16r/M) ・・・・・・
(5) Therefore, the equation of state of equation (3) is as follows, where the exciting current is 1des and the secondary magnetic flux λdea is v/d
By ea, the torque component ili flow i qe is ■(
It can be seen that it can be independently controlled by 1ea. The non-interference compensation circuit 6 realizes equations (4) and (5).

As mentioned above, since the excitation current and the torque current can be controlled independently, in FIG. Speed control is performed by a rotational angular velocity control circuit 11 having a minor loose circuit 10. Further, the field weakening setting circuit 9 allows constant output control by field weakening control.

[Problem that the invention seeks to solve]

Since the control device of the conventional induction TA machine is configured as described above, when the secondary time constant T of the motor changes due to temperature increase, the calculation error of the electrical angular velocity ω shown in equation (2) becomes large. . Therefore, the secondary winding flux linkage λ, 1er, λqe
There were problems such as the r and degO directions not matching each other, and transient deviations and steady-state deviations occurring in the torque.

This invention was made to solve the above-mentioned problems, and the secondary winding time constant Tr due to temperature changes in the motor
An object of the present invention is to obtain a control device k for an induction motor that can compensate for changes in .

[Means for solving problems]

The control device for an induction motor according to the present invention detects the qe-axis secondary winding flux linkage, multiplies the value by a gain, and sets the value as a correction value for the pes frequency, and also detects the qe-axis secondary winding flux linkage. Value 'f: The integrated value is used as a correction value for the secondary winding time constant.

[Effect]

The correction value for the overall frequency in this invention compensates for delays in the power converter and the control circuit, and the correction value for the secondary winding time constant is the correction value for the secondary winding 1g11 time constant of the motor. Compensates for temperature changes in the next winding time constant.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as in FIG. 6 are shown with the same reference numerals. In FIG. The computing unit 18 is a secondary winding resistance setting device.

Next, the operation will be explained. First, the rotational coordinate converter 16
search coil voltage ydf3c, which has been coordinate-transformed by
Vq8(! is input to the secondary flux linkage equivalent amount calculator 1T, and the amount equivalent to the secondary flux linkage is calculated.

The arithmetic expression is as shown in equation (7). .

Further, a block diagram of the secondary flux linkage equivalent amount calculator 1T is shown in FIG.

Here, P: differential operator 'd"c p yqelc' de axis l qe axis f
:"f Lumi pressure M8.M, mutual inductance of knee-order, secondary winding and search coil T knee-order delay time constant λ5e7.λc1e, = 6g axis qfj-axis secondary linkage magnetic flux equivalent amount λn1.λ6er is True secondary flux linkage λ
The following relationship exists between der *λqer.

At an operating point where the time constant T is sufficiently large and the electrical angular velocity ω is large to a certain extent, considering that 1/T in equation (8) is sufficiently small (1/T: O), λAe-λ, 1e, , λ( le
It may also be taken as r-scent e.

Now, the qa-axis secondary flux linkage is determined by the secondary winding resistance setting value Rr
When and the actual secondary winding resistance value R, match,
It remains zero regardless of the current value, but if they do not match, as shown in Figure 3, when the de-axis current 1d"lK is a positive value and constant, 'cleB/l deg K
There is a non-linear relationship. If this magnetic flux is detected and the set resistance value Rr is changed by the secondary winding resistance setter 18 so as to make it zero, the set resistance value becomes equal to the actual secondary winding resistance value R. This allows accurate torque control. Specifically, according to each quadrant in Figure 3, when 'qes>o and λ, er>0 (first quadrant)
Rr Increase gold when 'qea < o te, and λqer) O (second quadrant) R7 Decrease gold when iqe, < o and λq'r < 0 (third quadrant)
Increase R, when Qes > 0 and λ, increases 0 (4th quadrant) R
K should be set to decrease r. Therefore, the qe-axis secondary flux linkage equivalent tλqer, which is the output of the secondary flux linkage equivalent calculation unit 1T,
,! :(lem N flow λqe1B kara 2l winding B resistance e
QWi 1 B operates according to the above algorithm and provides a secondary time constant setting value to the secondary magnetic flux slip frequency calculation circuit 12.

Further, the details of the secondary winding resistance setting 618 are the same as shown in the fourth column. In this secondary winding resistance setter 18, the comparator 2
In step 9, the angular frequency ω0 and the electrical angular frequency ω at which λ4e and λqer& are approximately equal are compared, and when ω>ω0, a signal is sent to the switch circuit 32. The switch circuit 32 outputs 0 when there is no signal from the comparator circuit 2S, and outputs 1 as is the signal input from the multiplier circuit 31 when there is a signal. Further, 30 determines the sign of input signals i, e, and if positive, +
1, and if it is negative, it is a comparator that outputs -1. Since the polarity of the output of the multiplier circuit 31 is changed depending on the sign of t, ., the left half of FIG. Winding resistance R, mm)
When it is small, it is positive regardless of the input signal iq% value.

When Rr is large (Rr), it becomes negative. Therefore, if the output of the switch circuit 32 is input to the integrator 33 and set as the secondary winding resistance setting value Rr, R7 is increased when Rr is smaller than Rr, and R1 is decreased when Rr is larger than R1. By touching the secondary winding resistance set value Rr
and the actual secondary winding resistance Rr match.

Subsequently, the division circuit 34 outputs a secondary time constant setting value to the frequency calculation circuit 12, which calculates the secondary magnetic flux by Rr. In the above embodiment, the integrator 33 is used to set the secondary winding resistance setting value Rr, but if a proportional integrator is used, the speed of compensating for changes in the secondary winding resistance Rr becomes faster.

FIG. 5 shows another embodiment, in which circuits 1 to 18 are the first
Same as figure. Here, 35 is a proportional compensator which multiplies the output λ4er of the secondary flux linkage equivalent amount calculator 17 with a gain and adds it as the same wave number correction value. The reason for this is shown below.

The smooth frequency pω8 is expressed as when t:des is constant. From this and Fig. 3, if we compensate for the change in the secondary winding resistance with the pes frequency, then when 1qe8>0 and λ, Or>O (first quadrant), we add a positive subeff, 1q6B< O, and λqer) When Q (second quadrant), add the positive sum 1 When qe8<o and λqer<O [3 & limit] Add the negative sum 9, 'qea>o, k λqer< o no time (4th quadrant)
It is good to add negative slip. Therefore, the slip is corrected only by λqe2 without changing the signs of l and e8.

At this time, the secondary magnetic flux linkage and the direction of the de axis are set as perfect correction values ((do not match, because a proportional compensator can be used). Therefore, the secondary magnetic flux linkage on the qe axis is also zero. However, since this value compensates for Rr of the secondary winding resistance setter 18, the qe-axis secondary flux linkage becomes zero over time. This method has the effect of being able to correct the direction of the speed<d'' axis better than the method shown in FIG.

In addition, in the embodiment shown in FIG. 1, the secondary flux linkage equivalent calculation unit 17 using the search coil shown in FIG. Shadow caused by magnetic flux II! The amount equivalent to the secondary flux linkage may be obtained by performing first-order lag integration on the primary winding voltage after removing I't. The formula at this time is as follows.

Further, in the embodiment shown in FIG. 1, the electrical angular velocity ω is input to the input of the comparator 2S, but the mechanical angular velocity pω of the output of the coefficient unit 15 is
It may be 1.

〔Effect of the invention〕

As described above, according to the present invention, the circuit is configured to change the secondary winding resistance setting device using the qa-axis secondary magnetic flux linkage, so the secondary magnetic flux linkage and the de-axis coincide, and accurate This has the effect of providing excellent torque control.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an induction motor control device according to an embodiment of the present invention, Fig. 2 is a detailed block diagram of a secondary flux linkage equivalent computation unit, and Fig. 3 is a characteristic of the qe-axis secondary flux linkage. figure,
Fig. 4 is a block diagram of a secondary time constant setting value calculation circuit according to the present invention, Fig. 5 is a block diagram of an induction motor control device showing another embodiment of the invention, and Fig. 6 is a block diagram of a conventional induction motor control device. FIG. 2 is a block diagram of a motive control device. In the figure, 1 is a three-phase induction motor, 3 is a variable voltage variable frequency power converter, 4 and 5 are voltage and current coordinate conversion circuits, 6 is a non-interference compensation circuit, 12 is a secondary magnetic flux total υ frequency calculation circuit, 13 is an integrator, 14 is a sine and cosine wave generator, 1
5 is a coefficient unit, 16 is a rotating coordinate converter, 17 is a secondary interlinkage flux equivalent calculation unit, 18 is a secondary winding resistance setting device, and 35 is a proportional compensator. Poetry license applicant 3-L'J:,j 4,2, Co., Ltd. agent Patent attorney [1] Hiroshi Sawa (Other 2
name

Claims (3)

[Claims] (1) Supplying AC power controlled by a variable voltage variable frequency power converter to the primary winding of a three-phase induction motor, and adjusting the frequency of the output current of the variable voltage variable frequency power converter to the primary winding of the three-phase induction motor. a non-interference compensation circuit, a voltage, and a current which are calculated by an excitation current control circuit and a torque component current control circuit, and which control the amplitude of the output current by a magnetic flux command and a torque command of the three-phase induction motor; In an induction motor control device equipped with a control circuit such as a coordinate conversion circuit, a time constant setting value of a secondary winding of the induction motor used for calculation of the control circuit is set in parallel to a primary winding and a primary winding. The output voltage of the search coil is detected by a wound search coil, and the output voltage of the search coil is converted into a rotating coordinate system by a rotating coordinate converter, and then inputted to a secondary linkage flux equivalent amount calculator to calculate the output voltage of the three-phase induction motor. A secondary flux linkage equivalent is calculated from the primary winding current through the secondary flux linkage equivalent calculation unit, and a vector component of the secondary flux linkage equivalent is in the same direction as the torque component current. 1. A control device for an induction motor, characterized in that control is performed by a secondary winding resistance setter to match a time constant value of a secondary winding of the induction motor. (2) Out of the output of the secondary flux linkage equivalent amount calculator, the polarity of the vector component that is the same as the direction of the torque component current is changed depending on the polarity of the torque component current, and When the angular velocity is above a certain value, the vector component of the secondary interlinkage magnetic flux whose polarity has been changed is passed through a secondary winding resistance setting device including an integrator to become the time constant setting value of the secondary winding. A control device for an induction motor according to claim 1, characterized in that: (3) Among the outputs of the secondary flux linkage equivalent amount calculator, the polarity of the vector component that is the same as the direction of the torque component current is changed depending on the polarity of the torque component current, and the electric power of the three-phase induction motor or When the mechanical angular velocity is above a certain value, the vector component of the amount equivalent to the secondary interlinkage flux whose polarity has been changed is passed through a secondary winding resistance setting device including an integrator, and is set as the time constant setting value of the secondary winding. , among the secondary linkage magnetic flux equivalent, the vector component value that is the same as the direction of the torque component current is multiplied by a predetermined multiplier by a proportional compensator, and the frequency correction value that is the output of the proportional compensator is added to the electrical angular velocity. A control device for an induction motor according to claim 1, characterized in that the control device for an induction motor is configured as follows.