JPH11206166A - Speed controller for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain highly accurate speed in a motor, in which a frequency band in control system is enhanced even when a low output frequency is fed from a frequency generator in the motor. SOLUTION: A speed controller includes a cycle measuring means 3 for measuring a frequency signal(fs) from a frequency generator 2 mounted on a motor 1, and generating a rotational speed signal (N); a speed/load torque estimating means 8 for generating a monetary rotational speed estimation signal (n'), and a load torque estimation signal (τd') on the basis of a compensating signal (d) and the rotational speed signal (N); a comparing means 5 for generating deviation signal (Δ n) between the rotational speed command signal (nr) and a momentary rotational speed estimation signal (n'); a control means 6 for calculating a deviation signal (Δ n) and generating a control signal (c); a compensating means 9 for compensating the control signal (c) by using the load torque estimation signal (τ d'); a low frequency-range reinforcement means 10 for reinforcing the low frequency range of the compensation signal (d), and generating a current command signal (ci); and a driving means 4 for feeding a driving current (ia) to the motor according to the current command signal (ci).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a frequency generator (F)
More specifically, the present invention relates to a speed control device for a motor with G). More specifically, when the frequency of the frequency signal generated by the frequency generator is low, for example, when the rotation of the motor is controlled at low speed, or when the frequency and the frequency of the motor are high, the frequency and the frequency of the motor are high. The present invention relates to a motor speed control device capable of stabilizing a motor rotation control system and improving rotation accuracy even when a frequency generator that generates a signal cannot be configured.

[0002]

2. Description of the Related Art Recently, video tape recorders (hereinafter referred to as V
There is a remarkable reduction in size and weight of the camera-integrated VTR (hereinafter abbreviated as TR), and the motor used naturally has also been reduced in size and diameter. In particular, in a capstan motor in which a tape runs at a constant speed, a remarkable decrease in the moment of inertia of the rotor accompanying the miniaturization and the reduction in the diameter extremely deteriorates the rotation accuracy. In addition, when the capstan motor is rotated at a very low speed in order to realize long-time recording by reducing the tape speed of the VTR, the period of the frequency signal for detecting the rotation speed of the motor becomes longer, and the detection delay of the rotation speed becomes longer. Therefore, the control gain must be set low to stabilize the speed control system. Then, in order to increase the rotational accuracy due to the low inertia motor, the control gain must be set higher, but it cannot be made sufficiently high. As a result, in recent years, deterioration of control performance of these motors has become a problem.

Hereinafter, a conventional motor speed control device will be described with reference to the drawings. FIG. 8 is a block diagram showing an example of the most basic configuration of a conventional motor speed control device. In FIG. 8, 1 is a motor, 2 is a motor 1
A frequency generator (FG) 3 that generates a frequency signal fs proportional to the rotation speed of the frequency signal fs, and 3 is a cycle measuring unit that measures the cycle of the frequency signal fs. 5 is a deviation signal Δ between the speed signal N output from the cycle measuring means 3 and the speed command signal Nr (constant value).
A comparison means for outputting N; a control means for performing control compensation such as proportional and integral to the deviation signal ΔN and outputting a control signal c;
Reference numeral 4 denotes a driving unit that supplies a driving current ia to the motor 1 according to the control signal c.

Next, the operation of the conventional motor speed control device shown in FIG. 8 will be described. When the rotation speed of the motor 1 is controlled to be substantially constant, the frequency signal fs
Since the cycle of (1) is inversely proportional to the rotation speed of the motor 1, the output of the cycle measuring means 3 is used as the rotation speed detection result N. That is, the rotation speed of the motor 1 is
, And the detection result is held only for the period of the cycle. Therefore, the detection result N of the rotation speed by the cycle measuring means 3 is not the detection value of the instantaneous rotation speed at the time of sampling but an average rotation speed per cycle obtained by performing time integration over one cycle of the frequency signal fs.

FIG. 9 shows the actual instantaneous rotational speed n of the motor 1.
FIG. 7 is a diagram showing a relationship between the rotation speed N output from a cycle measuring unit 3. In FIG. 9, reference numeral 61 denotes a temporal change of the instantaneous rotational speed n of the motor 1, which is assumed to be changing as shown in the figure. Reference numeral 62 denotes a time change of the rotation speed N output from the cycle measuring means 3, and the rotation speed N is sampled by the frequency signal fs of the frequency generator 2 and indicates an average rotation speed in a period T. The rotation speed N is represented by t (i-1), t (i), and t in the cycle of the frequency signal fs as shown in FIG.
At the point of (i + 1),..., The value changes to a step, and a constant value is maintained during that period. 63 indicated by dotted line
Is the rotational speed of the motor 1 estimated from the rotational speed N of 62, and has a detection time delay of substantially T as compared with the actual instantaneous rotational speed n of the motor 1 as is apparent from FIG. As a result, when controlling the rotation speed using the conventional motor speed control device as described above, the control frequency band may be made too high to stabilize the control system due to the time delay of this detection. This cannot be performed (generally about 1/12 of the sampling frequency), and the response of the rotation control system cannot be improved.

[0006] In order to solve such a problem, several motor speed control devices capable of improving control performance have been conventionally proposed. For example, JP-A-61
Japanese Patent Application Laid-Open No. 30984/1992 discloses that a model representing the driving characteristics of a motor is constructed in a control device, and a speed detection value N calculated and calculated every time an output signal of a position detector is obtained, and a generated torque τm of the motor. A speed estimating means capable of estimating the instantaneous rotational speed n even in a section in which the output signal of the position detector does not change, and using the output signal of the speed estimating means as a speed feedback signal, the time for detecting the rotational speed is obtained. A motor speed controller with reduced delay is described.

The principle of the speed estimating means of the conventional motor speed control device will be described with reference to FIG. FIG. 10 is a block diagram showing a configuration of speed estimating means provided in a conventional motor speed control device. The speed estimating means 7 shown in FIG. 10 is inserted between the cycle measuring means 3 and the comparing means 5 in FIG.
The control signal c of the control means 60 supplied to the control means 60 is also input, and the estimated instantaneous rotational speed n ′ is output to the comparison means 5.

In FIG. 10, a multiplier 21 has a coefficient 1
/ (Jn · s) is a transfer function expressing the drive characteristics of the motor. Here, Jn is a nominal value representing the moment of inertia of the motor 1, and s is a Laplace operator. 22 is a proportional integral compensation element, k1 is a proportional constant, and k2 is an integral constant. A comparator 24 compares the output signal (estimated instantaneous rotational speed n ′) of the multiplier 21 with the rotational speed N output from the period measuring means 3 in FIG.
To enter. 28 is a multiplier, a coefficient (Ktn · gmn)
Is multiplied. Ktn and gmn are nominal values of the torque coefficient Kt of the motor 1 and the conversion coefficient gm of the driving means 4, respectively. Numeral 25 denotes a subtractor, which is an estimated value τm ′ of the generated torque of the motor 1 obtained by multiplying the control signal c by a coefficient (Ktn · gmn) by a multiplier 28 and a proportional integral compensation element 2
2 (the estimated value τd ′ of the load torque), and outputs the deviation to the multiplier 21.

Next, the operation of the speed estimating means 7 shown in FIG. 10 will be described in detail. In FIG. 10, the coefficient of the multiplier 21 is considered as a model expressing the driving characteristics of the motor.
There is a relationship of (Equation 1).

[0010]

(Equation 1) Therefore, if (Equation 1) is transformed by Laplace transform,
The relational expression of (Equation 2) is obtained.

[0011]

(Equation 2) From the equation (2), the instantaneous rotational speed n of the motor can be estimated. The estimated instantaneous rotational speed n ′ is obtained by calculating the difference between the estimated value τm ′ of the generated torque of the motor and the estimated value τd ′ of the load torque of the motor. Is obtained by time integration of a value obtained by dividing by the moment of inertia Jn. Therefore, in order to obtain the estimated instantaneous rotational speed n ′, the load torque τd
It is necessary to estimate the average instantaneous rotation speed n ′ obtained by the average speed detection value N of the period measuring means 3 in FIG.
The estimated value τd ′ of the load torque is estimated by proportional integration of the deviation from the above.

As described above, the estimated instantaneous rotational speed n ′ is estimated from the estimated load torque τd ′ and the estimated torque τm ′ generated by the motor.
Is used in place of the speed feedback signal (average speed detection value N) in FIG. 8 to control the speed of the motor 1. That is, by using the estimated instantaneous rotation speed n ′ estimated by the speed estimating means 7, the speed control can be performed using the speed signal with the detection delay reduced as the feedback signal. Speed signal N including delay
The control gain of the speed control system can be increased as compared with the case where speed control is performed using the feedback signal as it is as the feedback signal.

Further, in Japanese Patent Application Laid-Open No. 8-80080, the above-mentioned estimated value τd ′ of the load torque is controlled by the control means 60.
Is configured to perform feedforward compensation on the control signal c output from the control signal c. At this time, the motor 1 behaves as if no disturbance of the load torque τd was applied. However, the frequency band in which the effect of feedforward compensation can be substantially obtained is determined by the proportional constant k1 and the integral constant k2 of the proportional-integral compensation element 22. Therefore, the motor 1 has a load torque τd at a low frequency.
It is driven with high precision rotation accuracy which is hardly affected by external disturbance.

[0014]

However, there is an increasing demand for higher rotational accuracy of the motor, and further improvement in performance is desired. For example, in the case of a VTR for digital recording, a method of recording a video signal with a further increased compression ratio is being studied in the future. In this case, it is necessary to further reduce the tape speed, and inevitably, the tape drive is required. It is necessary to further improve the control performance of the capstan motor.

In view of the above problems, the present invention can sufficiently increase the control band of the control system even if the output frequency of the frequency generator mounted on the motor is low, and particularly, can reduce the frequency component of the load torque applied to the motor that is low. It is an object of the present invention to provide a motor speed control device that can significantly improve a disturbance suppressing force.

[0016]

According to a first aspect of the present invention, there is provided a motor speed control device for generating a frequency signal proportional to the motor rotation speed, and a frequency generator for measuring a period of the frequency signal to determine the rotation speed of the motor. Estimating the instantaneous rotational speed of the motor and the load torque applied to the motor using the period measuring means for outputting a corresponding rotational speed signal and the correction signal and the rotational speed signal to estimate the instantaneous rotational speed estimation signal and the load torque Speed / load torque estimating means for outputting a signal, a control signal generating means for performing a control operation using a rotational speed command signal and an instantaneous rotational speed estimating signal and outputting a control signal, and a control signal based on the load torque estimating signal. Correction means for correcting and outputting a correction signal, low-frequency enhancement means for enhancing a low-frequency component of the correction signal to generate a current command signal, and a motor for supplying a drive current according to the current command signal And a driving means for supplying.

According to a second aspect of the present invention, there is provided a speed control device for a motor.
A frequency generator that generates a frequency signal proportional to the rotation speed of the motor, a period measurement unit that measures a period of the frequency signal and outputs a rotation speed signal according to the rotation speed of the motor, and a control signal and a rotation speed signal. Speed for estimating the instantaneous rotational speed of the motor and the load torque applied to the motor and outputting an instantaneous rotational speed estimation signal and a load torque estimation signal.
Load torque estimating means, control signal generating means for performing a control operation using a rotational speed command signal and an instantaneous rotational speed estimating signal and outputting a control signal, and correcting the control signal with the load torque estimating signal and outputting a correction signal Correction means for increasing the low frequency component of the correction signal to generate a current command signal, and driving means for supplying a drive current corresponding to the current command signal to the motor.

According to a third aspect of the present invention, there is provided a motor speed control device,
3. The motor speed control device according to claim 1, wherein the control signal generation unit calculates a deviation between the rotation speed command signal and the instantaneous rotation speed estimation signal and outputs an instantaneous rotation speed error signal. And control means for performing a control operation on the instantaneous rotational speed error signal and outputting a control signal.

According to a fourth aspect of the present invention, there is provided a motor speed control device comprising:
A frequency generator that generates a frequency signal proportional to the rotation speed of the motor, a period measurement unit that measures the period of the frequency signal and outputs a rotation speed signal according to the rotation speed of the motor, a rotation speed command signal and a rotation speed signal A rotational speed error generating means for obtaining a deviation from the rotational speed error signal and estimating an instantaneous rotational speed error of the motor and a load torque applied to the motor using the correction signal and the rotational speed error signal. Speed error / load torque estimating means for outputting an instantaneous rotational speed error signal and a load torque estimation signal; correction signal generating means for outputting a correction signal using the instantaneous rotational speed error signal and the load torque estimation signal; The motor includes a low-frequency enhancement means for enhancing a low-frequency component and generating a current command signal, and a driving means for supplying a drive current corresponding to the current command signal to the motor.

According to a fifth aspect of the present invention, there is provided a motor speed control device comprising:
5. The motor speed control device according to claim 4, wherein the correction signal generating means performs a control operation on the instantaneous rotational speed error signal and outputs a control signal, and a correction signal which corrects the control signal with a load torque estimation signal. And a correction means for outputting A motor speed control device according to claim 6, wherein the frequency generator generates a frequency signal proportional to the rotation speed of the motor, and a period that measures the period of the frequency signal and outputs a rotation speed signal according to the rotation speed of the motor. Measuring means, a rotational speed error generating means for calculating a deviation between the rotational speed command signal and the rotational speed signal and outputting a rotational speed error signal, and an instantaneous rotational speed error of the motor using the control signal and the rotational speed error signal. Speed error / load torque estimation means for estimating the load torque applied to the motor and outputting an instantaneous rotational speed error signal and a load torque estimation signal; and a control signal using the instantaneous rotational speed error signal and the load torque estimation signal. Control / correction signal generating means for outputting a correction signal, a low frequency enhancement means for enhancing a low frequency component of the correction signal to generate a current command signal, and a drive power supply corresponding to the current command signal. The and a driving means for supplying to the motor.

A motor speed control device according to claim 7 is
7. The motor speed control device according to claim 6, wherein
The correction signal generating means includes control means for performing a control operation on the instantaneous rotational speed error signal and outputting a control signal, and correction means for correcting the control signal with a load torque estimation signal and outputting a correction signal. I do. According to the configuration of the present invention, the instantaneous rotational speed of the motor (cases 1 to 3) and the instantaneous rotational speed error of the motor (cases 4 to 7) are estimated, and such speed estimation information is used. Control operation, the control band of the control system can be sufficiently increased even if the output frequency of the frequency generator attached to the motor is low, and the motor rotates with respect to disturbance of frequency components with high load torque applied to the motor. Can be made more accurate.

Further, it is possible to easily realize the load torque applied to the motor by estimating the load torque applied to the motor and canceling the load torque applied to the motor by the correction means or the correction signal generation means and the control / correction signal generation means. It is possible to improve the rotation accuracy with respect to the load torque disturbance, and to make correction means or correction signal creation means,
By the operation of the low-frequency boosting means connected in series to the correction signal generating means, it is possible to greatly increase the suppression force against disturbance of the load torque of low frequency components.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a block diagram showing a configuration of a motor speed control device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a motor driven by a drive current ia. The motor 1 rotates by generating a drive torque τm, and a disturbance torque τd due to a load is applied to a rotating shaft. 2 is a frequency signal f proportional to the rotation speed of the motor 1.
A frequency generator 3 for generating s, a cycle measuring means 3 for measuring a cycle of the frequency signal fs and outputting a rotation speed signal N, and 4 for supplying a driving current ia to the motor 1 according to the current command signal ci. Drive means. 9 is a correction means,
The control circuit 6 is configured to perform feedforward compensation on the control signal c output from the load torque estimation value τd ′ created by the operation of the speed / load torque estimation means 8. Further, the speed / load torque estimating means 8 obtains the estimated torque τm ′ of the motor 1 from the correction signal d output from the correcting means 9 and calculates the instantaneous torque of the motor 1 from the estimated torque τm ′ and the rotation speed signal N. Finding the rotation speed n '
Output to comparison means 5. The comparing means 5 (instantaneous rotational speed error creating means) outputs a deviation signal Δn (instantaneous rotational speed error signal) between the instantaneous rotational speed estimation signal n ′ and the rotational speed command signal nr (constant value). The control means 6 performs control compensation such as proportionality and integration on the deviation signal Δn and outputs a control signal c.
Here, description will be made assuming that the control means 6 performs only proportional control compensation for simplification. Reference numeral 10 denotes a low-frequency enhancement unit that performs a filtering process on the correction signal d so as to enhance a low-frequency component, and outputs a current command signal ci to the driving unit 4. As will be described in detail later, the low-frequency enhancement means 10 has a characteristic that it has a predetermined gain A in a high frequency range and a larger gain in a low frequency range.
The comparing means 5 and the control means 6 are control signal creating means.

The operation of the motor speed control device of the present embodiment configured as described above will be described in detail. In FIG. 1, when the rotation speed of the motor 1 is controlled to be substantially constant, the frequency signal f
Since the period of s is inversely proportional to the rotation speed of the motor 1, the output of the period measurement means 3 is used as the detection result of the rotation speed. For example, the cycle measuring means 3 measures the cycle of the frequency signal fs using a counter or the like, and uses the counter value as it is as the detection result of the rotation speed (= rotation speed signal N). Of course, the conversion from the frequency signal fs to the rotation speed signal N requires consideration of the gain including the above-mentioned counter and the like, but the description is omitted here. That is, the rotation speed of the motor 1 is sampled at the cycle of the frequency signal fs of the frequency generator 2, and the detection result is held for the cycle time. Therefore, the detection result of the rotation speed (= rotation speed signal N) is not an instantaneous value at the time of sampling but an average value of the frequency signal fs in the cycle time, and naturally includes a detection delay.

The following description will be made with reference to FIG. FIG. 2 is a diagram showing a detailed configuration of the motor speed control device of FIG. 1, particularly an internal configuration of the motor 1, the speed / load torque estimating means 8 and the correcting means 9. The motor 1 includes a multiplier 11 for multiplying the torque coefficient Kt, an adder 12 for inverting and adding (subtracting) the load torque τd, and a coefficient (transfer function 1 / Js).
And a multiplier 13 for multiplying by. The coefficient of the multiplier 13 is a transfer function of the motor including the frequency generator 2 in FIG.

The speed / load torque estimating means 8 includes a multiplier 8
1, 88, an integral compensating element 82, an integrator 83, and subtractors 84 and 85, and the generated torque estimated value τm ′ (= Kt · i) corresponding to the correction signal d output from the correcting means 9.
a = Kt · gm · d · A; Kt is the torque coefficient of the motor 1, gm is the conversion coefficient of the driving means 4, and A is the low-frequency enhancement means 1
0 in a high frequency range) by a multiplier 88, and using the generated torque estimated value τm ′ and the rotation speed signal N output from the cycle measuring means 3, the frequency signal fs output from the frequency generator 2 is calculated. The instantaneous rotation speed n ′ in a period in which the signal does not change (a period in which the zero-cross point of the signal is not detected) is estimated. Here, the speed is estimated by calculating the difference between the estimated torque τm ′ generated by the motor 1 according to the correction signal d and the estimated load torque τd ′ applied to the motor 1 as shown in (Equation 2) in the conventional example. Is divided by the moment of inertia of the motor 1 to perform time integration. Therefore, it is necessary to estimate the load torque τd. Therefore, the load torque estimation value τd ′ is obtained by proportional integration of the deviation between the rotation speed signal N output from the cycle measuring means 3 and the estimated instantaneous rotation speed n ′.
From the estimated load torque τd ′ and the estimated torque τm ′ of the motor 1 corresponding to the correction signal d, the instantaneous rotational speed n ′ is calculated.
, The delay in speed detection is reduced.
The speed / load torque estimating means 8 calculates the estimated instantaneous rotational speed n ′.
The estimated instantaneous rotational speed n ′ is used as a feedback signal for speed control, and is input to the comparing means 5.
On the other hand, the estimated load torque value τd ′ is input to the correction unit 9.

The comparing means 5 and the control means 6 control the speed / load torque estimating means 8 according to the rotational speed command signal nr.
The speed control of the motor 1 is performed using the instantaneous rotation speed n ′ estimated in the above as a feedback signal. Such an estimated instantaneous rotational speed n ′
, The control frequency band can be expanded. Further, in the present embodiment, the load / torque estimation value τd ′ obtained by calculation inside the speed / load torque estimation means 8 is configured to perform feedforward compensation on the control signal c output from the control means 6. .

The correction means 9 includes a control signal c of the control means 6 and an estimated load torque τd 'of the speed / load torque estimation means 8.
Is input, and a correction signal d is output to the low-frequency enhancement unit 10 after performing the correction operation. In the correction means 9, a multiplier 91 is multiplied by a coefficient 1 / (Ktn · gmn · A) and output. Reference numeral 92 denotes an adder, which adds the operation result of the multiplier 91 to the control signal c output from the control means 6 and outputs the result to the low-frequency enhancement means 10 as a correction signal d. Correction signal d
Can be represented by (Equation 3).

[0029]

(Equation 3) Therefore, the generated torque τm of the motor 1 is equal to the correction signal d
Is multiplied by the gain A of the current intensifying means 10, the conversion coefficient gm of the driving means 4, and the torque coefficient Kt of the motor 1, and is represented by (Equation 4).

[0030]

(Equation 4) Here, for simplicity, Ktn = Kt and gmn = gm. Therefore, the load torque estimated value τd ′ output from the speed / load torque estimating means 8 is multiplied by the multiplier 81 and the integral compensation element 8.
And the load torque τd applied to the motor 1 in a frequency range equal to or lower than the control band of the loop constituted by the integrator 83 and the integrator 83.
Therefore, the actual load torque τd and the estimated load torque value τd ′ are canceled in the adder 12 constituting the motor 1. In other words, the motor 1 behaves as if the disturbance of the load torque τd was not applied to the multiplier 13 (the coefficient is 1 / Js) by performing the feedforward compensation on the estimated load torque τd ′ by the correction means 9. Therefore, the motor 1 operates at a low frequency.
The drive is performed with high precision without substantially being affected by disturbance of the load torque τd.

Further, in the present embodiment, the low-frequency enhancement means 10 is connected in series with the correction means 9, and the current command signal ci, which is the output of the low-frequency enhancement means 10, is supplied to the driving means 4.
Is being entered. FIG. 3 shows a frequency characteristic diagram of the low-frequency enhancement means 10. The characteristic has a predetermined gain A in a high frequency region and a large gain in a low frequency region.

The effect of the configuration in which the low frequency band enhancing means 10 is inserted as described above will be described below. In a conventional example (for example, JP-A-8-80080),
It is described that the control means 6 in the present embodiment is configured to include the low-frequency enhancement means. A comparison with such a case will be described with reference to FIG. FIG. 4 shows a disturbance suppression characteristic (a transmission characteristic from the disturbance torque τd to the rotation speed n of the motor 1) in the motor speed control device using a Bode diagram. It is well known that the smaller the gain level of the disturbance suppression characteristic, the better the control performance. FIG. 4A shows an example of a disturbance suppression characteristic in a case where the low-frequency enhancement means is omitted as compared with the present embodiment, and FIG. 4B shows a control as considered in the conventional example. This is an example of the disturbance suppression characteristic when the means 6 is configured to include the low-frequency enhancement means, and FIG. 3C is an example of the disturbance suppression characteristic in the present embodiment.
As described above, in the present embodiment, the control means 6 performs only the proportional compensation control (corresponding to (a) and (c) in FIG. 4). Here, as can be seen from the transfer function shown in FIG.
Shows a case where a filter having the first order characteristic is used.

As is apparent from FIG. 4, when the configuration according to the present embodiment is employed, disturbance suppression in the low frequency region is significantly improved as compared with the conventional example. In the case of FIG. 4B, the characteristic has a primary characteristic in a low frequency range, whereas in the case of FIG. 4C, the characteristic can have a secondary characteristic. This difference appears as a difference in disturbance suppression characteristics in a low frequency range. In many cases, the low-frequency component is dominant as the load torque component applied to the motor 1. Therefore, by adopting the configuration of the present embodiment, the speed control of the motor that is extremely strong against the disturbance torque applied to the motor 1 is performed. The device can be realized.

[Second Embodiment] FIG. 5 shows a second embodiment of the present invention.
FIG. 3 is a block diagram illustrating a detailed configuration of a motor speed control device according to the embodiment. Note that components having the same functions as those in FIG. 2 are denoted by the same reference numerals, and redundant description will be omitted. The second embodiment shown in FIG. 5 corresponds to the speed / load torque estimating means 8 in the first embodiment shown in FIG.
Instead, the speed / load torque estimating means 20 is used, and the other configuration is the same as that of FIG. The speed / load torque estimating means 20 receives the rotation speed signal N from the cycle measuring means 3 because the speed / load torque estimating means 8 shown in FIG.
However, while the speed / load torque estimating means 8 receives the correction signal d from the correcting means 9, the speed / load torque estimating means 20 receives the control signal c from the control means 6. It is configured. The load torque estimated value τd ′ of the output of the speed / load torque estimating means 20 is represented by
As in the case of (1), the correction signal d is input to the correction means 9, the correction operation is performed by the correction means 9, and then the correction signal d is input to the low-frequency enhancement means 10. Paying attention to the speed / load torque estimating means, the speed / load torque estimating means 8 shown in FIG. 2 requires the subtractor 85, but the speed / load torque estimating means 20 shown in FIG. It has been simplified by being replaced by a container 86.

Hereinafter, the present embodiment will be described in more detail. First, in FIG. 2, an estimated acceleration torque τ ′ which is an input of the multiplier 81 constituting the speed / load torque estimating means 8 can be expressed by (Equation 5). The correction signal d of the correction means 9 is represented by (Equation 6).

[0036]

(Equation 5)

[0037]

(Equation 6) Therefore, the estimated acceleration torque τ ′ can be expressed by (Equation 7) from (Equation 5) and (Equation 6).

[0038]

(Equation 7) Rewriting the speed / load torque estimating means 8 of FIG. 2 based on this (Equation 7), the speed / load torque estimating means 2 of FIG.
It will be like 0. That is, the control signal c of the control means 6 is input to the multiplier 88, multiplied by the coefficient (Ktn · gmn · A), and further, the estimated acceleration torque τ ′ can be obtained through the operation of the subtractor 86. The estimated acceleration torque τ ′ is input to a multiplier 81, and can be multiplied by a coefficient 1 / (Jn · s) to obtain an estimated instantaneous rotational speed n ′.

On the other hand, the estimated load torque τd ′ is input to the correcting means 9, and the estimated load torque τd ′ output from the speed / load torque estimating means 20 is determined by the load applied to the motor 1, as in FIG. Since the torque is equal to τd, the adder 1
2, the actual load torque τd and the estimated load torque τ
d 'is canceled. Therefore, as in the embodiment of FIG. 2, the motor 1 has a load torque τ at a low frequency.
The drive is performed with high rotational accuracy without being affected by the disturbance of d. The effect of inserting the low-frequency enhancement means 10 is the same as that of the first embodiment.

In recent years, the speed / load torque estimating means 20, the control means 6, the correcting means 9 and the like are often realized by software processing by a microprocessor, and are expected to become mainstream in the future. In that case, the multiplication operation of the multiplier 91 of the correcting means 9 and the coefficient k2 of the integrator 83 of the speed / load torque estimating means 20 can be performed at once. A multiplication operation in a processor generally takes a long processing time. When the speed control device is configured by software processing of the microprocessor, it is very advantageous that the number of times of multiplication can be reduced. As described above, according to the present embodiment, it is possible to realize a high-performance motor speed controller with a simpler configuration than the embodiment of FIG.

Further, the merits of inserting the low frequency band enhancing means 10 in this embodiment will be described. As described above, in recent years, a motor speed control device is often realized using a microprocessor. In this case, a digital value is used as the speed information value handled in the speed controller, but the average speed detection value (rotation speed signal N) generated by the period measuring means 3 is a clock (for example, a clock for measuring the period). 10 MHz) and a value determined by the frequency signal fs (for example, 500 Hz). That is, in the speed / load torque estimating means 20, the control means 6, the correcting means 9, and the like, it is necessary to perform calculations in consideration of the detection gain of the cycle measuring means 3. In the speed / load torque estimating means 20, the constant k
It is necessary to determine 1, k2, etc. by converting the speed detection gain. However, the clock frequency for speed detection is set high in order to increase the rotation accuracy, and the motor 1
When the is rotated at a low speed, the speed detection gain becomes a very large value. In this case, since the constants k1 and k2 need to be values converted from the speed detection gain,
In particular, the constant k2 may have a very small value. At this time, in digital processing by software or the like, so-called bit omission or the like occurs after multiplication by a constant, that is, it is impossible to perform an accurate operation.

As an example of a countermeasure in such a case, it is conceivable that a predetermined gain smaller than 1 is simply provided at the position where the low-frequency enhancement means 10 is inserted, instead of the low-frequency enhancement means. . At that time, the multiplier 91 of FIG.
Since the constant A is smaller than 1, that is, the multiplier 91 multiplies a large value, and the multiplication operation of the multiplier 91 and the constant k2 of the integrator 83 is united, the above-mentioned result is obtained. The problem of dropped bits can be avoided.

However, in this case, it should be noted that the operation result of the multiplier 91 compensates for the DC component of the load torque with respect to the load torque estimation signal τd ′. That is, multiplying a gain smaller than 1 by the correction signal d (the correction signal d without the low-frequency enhancement means 10 also compensates for the DC component of the load torque) means that the correction means 9 or the speed / load torque When calculating a value corresponding to the dimension of the load torque inside the estimating means 20, it becomes necessary to handle a very large value.
In that case, the bit length required for the operation increases, that is, a problem arises in that the amount of memory required for the operation increases.

The above problem can be solved by inserting the low frequency band enhancing means 10 as shown in the present embodiment. By inserting the low-frequency enhancement means 10, the correction signal d has a configuration in which substantially only the AC component of the load torque is compensated. If the low-frequency enhancement means 10 has a predetermined gain A in the high frequency range, the above-described problem of bit drop can be avoided.
Further, the fluctuation component of the load torque compensated by the calculation result of the multiplier 91 is an AC component of the load torque to the last, and there is no problem that the bit length necessary for the above-described partial calculation is increased. In other words, the low-frequency enhancement means 10 can realize a highly accurate motor speed control device with a simple configuration even during digital processing of software or the like.

As described above, according to the present embodiment, the speed control of the motor is extremely small with respect to the disturbance of the load torque, and can be economically implemented even in the digital processing that is currently mainstream. The device can be realized. [Third Embodiment] FIG. 6 is a block diagram showing a detailed configuration of a motor speed control device according to a third embodiment of the present invention. Note that components having the same functions as those in FIG. 2 are denoted by the same reference numerals, and redundant description will be omitted. Also,
The control means 6 and the correction means 9 are correction signal creation means.

The third embodiment shown in FIG.
Is a comparison means 50 (rotational speed error creation means) and a speed error / load torque estimation means 30 instead of the comparison means 5 and the speed / load torque estimation means 8 in the first embodiment shown in FIG. Other configurations are the same as those in FIG. That is, although the internal configuration of the speed error / load torque estimating means 30 is the same as that of the speed / load torque estimating means 8 of FIG. 2, the insertion position of the comparing means 50 is different from that of FIG. 2 (comparing means 5). Comparison means 50 is applied to the output of cycle measurement means 3
And the output of the comparing means 50 is input to the speed error / load torque estimating means 30.

The comparing means 50 outputs a rotation speed error signal ΔN which is a deviation signal between the rotation speed signal N and the rotation speed command signal nr (constant value). Then, the speed error / load torque estimating means 30 outputs a load torque estimated value τd ′ and an instantaneous rotational speed error signal (= Δn). This instantaneous rotational speed error signal Δn is completely equivalent to the deviation signal Δn described with reference to FIG. Speed / load torque estimation means 8 in FIG.
Calculated the load torque estimated value τd ′ by proportionally integrating the deviation between the rotational speed signal N and the estimated instantaneous rotational speed n ′. On the other hand, the speed error / load torque estimating means 30 in FIG. 6 calculates the load torque estimated value τd ′ by proportionally integrating the deviation between the rotational speed error signal ΔN and the instantaneous rotational speed error signal Δn. After all, since the load torque estimation value τd ′ is calculated by calculating the deviation, the obtained load torque estimation value τd ′ is equivalent. Based on such an equivalent load torque estimated value τd ′, the speed / load torque estimating means 8 in FIG. 2 calculates in the dimension of the absolute value of the speed.
The only difference is that the load torque estimating means 30 performs the calculation in the dimension of the speed error, and eventually becomes equivalent as the deviation signal Δn input to the control means 6. Therefore, the characteristics obtained as the control device are equivalent in the case of the embodiment of FIG. 2 and in the case of the embodiment of FIG.

That is, also in the present embodiment, the motor 1 can be rotated with high accuracy and with high accuracy, as in the case of the embodiment of FIG. Further, according to the present embodiment, the information on the speed in the speed error / load torque estimating means 30 is handled not by the absolute value of the speed but by the amount of error. When the configuration of the embodiment is realized, the bit length of the value handled in each block can be reduced. That is, in this case, the memory usage can be reduced. Therefore, according to the present embodiment, a high-performance motor speed control device can be realized very economically.

[Fourth Embodiment] FIG. 7 shows a fourth embodiment of the present invention.
FIG. 3 is a block diagram illustrating a detailed configuration of a motor speed control device according to the embodiment. Note that components having the same functions as those in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted. Further, the control means 6 and the correction means 9 are control / correction signal creation means. In the fourth embodiment shown in FIG. 7, instead of the comparing means 5 and the speed / load torque estimating means 20 in the second embodiment shown in FIG. 5, a comparing means 50 (rotational speed error creating means) and The speed error / load torque estimating means 40 is used.
Is the same as That is, although the internal configuration of the speed error / load torque estimating means 40 is the same as that of the speed / load torque estimating means 20 of FIG. 5, the insertion position of the comparing means 50 is different from that of FIG. 5 (comparing means 5). The comparison means 50 is connected to the output of the cycle measurement means 3, and the output of the comparison means 50 is input to the speed error / load torque estimation means 40.

The comparing means 50 outputs a rotation speed error signal ΔN which is a deviation signal between the rotation speed signal N and the rotation speed command signal nr (constant value). Then, the speed error / load torque estimating means 40 outputs a load torque estimated value τd ′ and an instantaneous rotational speed error signal (= Δn). 2 and the embodiment of FIG. 6 are equivalent in the characteristics as the control device, and the embodiment of FIG. 7 is the same as the embodiment of FIG. The characteristics of the device are equivalent. That is, also in the present embodiment, as in the case of the embodiment of FIG.
It is possible to rotate the motor 1 with high accuracy.

Further, according to the present embodiment, FIG.
Compared to the case of the embodiment shown in FIG. 6, since the information on the speed in the speed error / load torque estimating means 40 is handled not by the absolute value of the speed but by the amount of error, the case of the embodiment shown in FIG. Similarly, when the configuration of the present embodiment is realized by software processing by a microprocessor, for example, the memory usage can be reduced. Therefore, according to the present embodiment, a high-performance motor speed control device can be realized very economically.

In the embodiment of the present invention, the multiplier 8
Although 1 and the integral compensating element 82 are shown in the drawing as being constituted by an analog filter, it is needless to say that they may be constituted by a digital filter. Further, each unit constituting the control device may be realized by software by a microcomputer. Further, although the example in which the low-frequency enhancement means 10 is configured by an analog filter is shown, it may be configured by a digital filter, and the case where the low-frequency enhancement means 10 is realized by software by a microcomputer including the low-frequency enhancement means 10 is also included. Needless to say.

In the embodiment of the present invention, the control output signal of each unit is described as a continuous signal. However, the control device may be constituted by a microcomputer, and the control output signal of each unit may be output as a discrete signal. If the output sampling period is sufficiently shorter than the period of the frequency signal fs output from the frequency generator 2, the same effect as in the case of a continuous signal can be obtained.

Further, in the above-described embodiment of the present invention, the case where only the speed control is performed has been described.
The present invention also includes a case in which the control means 6 and the like perform a phase control to match the rotation phase with a predetermined phase reference using the rotation phase information.

[0055]

As described above, according to the motor speed control device of the present invention, the instantaneous rotational speed of the motor (in the case of claims 1 to 3)
And the instantaneous rotational speed error of the motor (in the case of claims 4 to 7) is estimated, and the control operation is performed using such speed estimation information. Therefore, even if the output frequency of the frequency generator attached to the motor is low, The control band of the speed control system can be sufficiently increased, and high-precision rotation can be performed with respect to disturbance of a frequency component having a high load torque applied to the motor.

Further, it is possible to easily realize the load torque applied to the motor by estimating the load torque applied to the motor and canceling the load torque applied to the motor by the correction means or the correction signal generation means and the control / correction signal generation means. It is possible to improve the rotation accuracy with respect to the load torque disturbance, and to make correction means or correction signal creation means,
By the operation of the low-frequency boosting means connected in series to the correction signal generating means, it is possible to greatly increase the suppression force against disturbance of the load torque of low frequency components.

As described above, when the output frequency of the frequency generator attached to the motor is low, for example, when the rotation of the motor is controlled at a low speed, or when the frequency generator generates a high frequency signal in terms of the structure and cost of the motor. Even when the motor cannot be configured, the control bandwidth of the speed control system can be sufficiently increased with a relatively simple configuration, and the effect of the load component applied to the motor on the disturbance of high frequency components is sufficiently reduced. In addition, it is possible to greatly reduce disturbance of a frequency component having a low load torque, that is, to realize a motor speed control device capable of achieving high-precision rotation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a motor speed control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a motor speed control device according to the first embodiment of the present invention.

FIG. 3 is a frequency characteristic diagram of the low frequency band enhancing means according to the first embodiment of the present invention.

FIG. 4 is a diagram showing the effect of disturbance suppression characteristics in the first embodiment of the present invention.

FIG. 5 is a block diagram showing a detailed configuration of a motor speed control device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a detailed configuration of a motor speed control device according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a detailed configuration of a motor speed control device according to a fourth embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a conventional motor speed control device.

FIG. 9 is a diagram showing a relationship between an instantaneous rotational speed n and an average rotational speed N of a motor in a conventional example.

FIG. 10 is a block diagram of speed estimating means provided in a conventional motor speed control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Frequency generator 3 Period measuring means 4 Driving means 5 Comparison means (instantaneous rotational speed error creation means) 6 Control means 8, 20 Speed / load torque estimation means 9 Correction means 10 Low frequency enhancement means 30, 40 Speed error / Load torque estimation means 50 Comparison means (rotation speed error creation means)

Claims (7)

[Claims] A frequency generator that generates a frequency signal proportional to the rotation speed of the motor; a period measurement unit that measures a period of the frequency signal and outputs a rotation speed signal according to the rotation speed of the motor; Speed / load torque estimating means for estimating an instantaneous rotational speed of the motor and a load torque applied to the motor using the signal and the rotational speed signal to output an instantaneous rotational speed estimation signal and a load torque estimation signal Control signal generating means for performing a control operation using a rotation speed command signal and the instantaneous rotation speed estimation signal and outputting a control signal; and correcting the control signal with the load torque estimation signal to output the correction signal. A low-frequency enhancement means for enhancing a low-frequency component of the correction signal to generate a current command signal; and supplying a drive current corresponding to the current command signal to the motor. A motor speed control device comprising: a driving unit for supplying the motor. 2. A frequency generator for generating a frequency signal proportional to the rotation speed of the motor, a period measurement means for measuring a period of the frequency signal and outputting a rotation speed signal according to the rotation speed of the motor, Speed / load torque estimating means for estimating an instantaneous rotational speed of the motor and a load torque applied to the motor using the signal and the rotational speed signal to output an instantaneous rotational speed estimation signal and a load torque estimation signal Control signal generating means for performing a control operation using the rotation speed command signal and the instantaneous rotation speed estimation signal and outputting the control signal; and correcting the control signal with the load torque estimation signal to output a correction signal. Correction means; low-frequency enhancement means for enhancing a low-frequency component of the correction signal to generate a current command signal; and supplying a drive current according to the current command signal to the motor. Speed control device provided with a driving means for driving. 3. An instantaneous rotational speed error creating unit that calculates a deviation between a rotational speed command signal and an instantaneous rotational speed estimation signal and outputs an instantaneous rotational speed error signal; 2. A control means for performing a control operation and outputting a control signal.
Or the motor speed control device according to 2. 4. A frequency generator for generating a frequency signal proportional to the rotation speed of the motor, a period measurement means for measuring a period of the frequency signal and outputting a rotation speed signal according to the rotation speed of the motor, A rotation speed error generating means for calculating a deviation between a speed command signal and the rotation speed signal and outputting a rotation speed error signal; an instantaneous rotation speed error of the motor and the motor using a correction signal and the rotation speed error signal; Speed error / load torque estimating means for estimating a load torque applied to and outputting an instantaneous rotational speed error signal and a load torque estimation signal, and using the instantaneous rotational speed error signal and the load torque estimation signal Correction signal generating means for outputting a correction signal; low-frequency enhancement means for enhancing a low-frequency component of the correction signal to generate a current command signal; A motor speed control device comprising: driving means for supplying a driving current to the motor. 5. A correction signal generating means, comprising: a control means for performing a control operation on an instantaneous rotational speed error signal and outputting a control signal; a correction means for correcting the control signal with a load torque estimation signal and outputting a correction signal. The motor speed control device according to claim 4, comprising: 6. A frequency generator for generating a frequency signal proportional to a rotation speed of a motor, a period measurement unit for measuring a period of the frequency signal and outputting a rotation speed signal according to the rotation speed of the motor, A rotation speed error generating means for calculating a deviation between a speed command signal and the rotation speed signal and outputting a rotation speed error signal; an instantaneous rotation speed error of the motor and the motor using a control signal and the rotation speed error signal; Speed error / load torque estimating means for estimating a load torque applied to and outputting an instantaneous rotational speed error signal and a load torque estimation signal, and using the instantaneous rotational speed error signal and the load torque estimation signal Control / correction signal generation means for outputting a control signal and a correction signal; low-frequency enhancement means for enhancing a low-frequency component of the correction signal to generate a current command signal; A drive unit for supplying a drive current according to a command signal to the motor; 7. A control / correction signal generating means for performing a control operation on the instantaneous rotational speed error signal and outputting a control signal, and a correction for correcting the control signal with a load torque estimation signal and outputting a correction signal 7. The motor speed control device according to claim 6, wherein the speed control device comprises: