JP2002044976A - Motor speed control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor speed control device, which realizes stable control, improving its control accuracy with respect to disturbances, using simple adjustment, even when it drives a mechanical load which has low mechanical rigidity and inertia larger than that of the motor. SOLUTION: There are provided a first low-pass filter 13, which outputs a signal which filters low-frequency components by inputting a signal, which represents an actual speed which is the rotational speed of the motor; first control calculators 14, 15 which calculate a low region torque instruction according to a difference between a signal which proportionally multiplies the output of the first low-pass filter; and a signal according to a difference between the speed instruction for the motor speed control and the output of first low-pass filter and second control calculators 16, 17 which calculate torque instruction, according to a difference between a signal based on the proportional multiple of the actual speed and the low region torque instruction by inputting the low region torque instruction and the actual speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control device for a motor used in elevators, industrial machines, and the like.

[0002]

2. Description of the Related Art FIG. 5 shows, for example, "Adaptive Control of Servo Motor", Measurement and Control, Vol. 32, No. 12, pp. 1010 to 1013.
FIG. 2 is a diagram showing a configuration of a conventional speed control device for an electric motor of this type described in FIG. Although the above document describes the position control device, since it includes a speed control device inside,
FIG. 5 illustrates only the speed control portion. In the figure, reference numeral 1 denotes a control object including a motor torque controller, a motor and a mechanical system of a load and a speed detector (both not shown),
2 is a model calculation unit, 24 is a proportional controller, and 25 is an integral controller.

Next, the operation will be described. First, the controlled object 1 inputs a torque command qr, and the controlled object 1 internally drives a motor and a mechanical system serving as a load by controlling the torque of the motor so as to match the torque command qr by a torque controller. The speed detector detects the actual speed vm which is the speed of the electric motor. The transfer characteristic from the torque command qr to the actual speed vm is described as G (s).

Next, the operation of the model calculation section 2 will be described. The model calculation unit 2 receives a speed command vr from outside. Further, a model of the control target 1 is assumed in advance, and a model speed va as a model speed and a model torque qa as a model torque are calculated so that the model speed va follows the speed command vr.

For example, assuming that the model of the controlled object 1 assumed in the model calculation unit 2 is a rigid machine whose inertia is Ja, the model torque qa is calculated by multiplying the model acceleration va by the model inertia Ja. Therefore, the model calculation unit 2 calculates the model speed va and the model torque qa by the following equations (1) and (2), for example. Hereafter, s represents the Laplace operator.

Va = F (s) · vr (1) qa = J · s · F (s) · vr (2)

However, in the above equation, F (s) is the speed command vr
Is a desired transfer characteristic that causes the model speed va to follow, for example, is set as a low-pass transfer characteristic.

Next, a method of calculating the torque command qr will be described. The proportional controller 24 has a model speed va and an actual speed v
The integral controller 25 outputs a signal obtained by multiplying the deviation between the model speed va and the actual speed vm by the preset integral gain Ki, and outputs a signal obtained by multiplying the deviation of m by a preset proportional gain Kp. The sum of the output of the proportional controller 24 and the output of the integration controller 25 is defined as an error compensation torque qc. That is, PI (proportional integration) calculation is performed. Further, the sum of the model torque qa calculated by the model calculation unit 2 and the error compensation torque qc is output as a torque command qr, and the torque command qr is
To drive the mechanical system of the control target 1.

In this prior art, the transfer characteristic G (s) of the controlled object 1 is reduced by
In the case where the characteristics of the model assumed in the above are matched, that is, when the characteristics of the controlled object 1 match the rigid body whose inertia is Ja, the torque command qr matches the model torque qa with respect to the input of the speed command vr, and The actual speed vm is controlled so as to completely match the model speed va.

In addition, the transfer characteristic G of the controlled object 1 is actually
(s) causes an error with the characteristics of the model calculation unit 2 and a disturbance torque is applied to the control target 1, so that the actual speed vm does not completely match the model speed va, and the error is equal to the proportional controller 24. Then, the feedback is fed back via the integration controller 25 and added to the model torque qa as an error compensation torque qc to become a torque command qr, and control is performed so that the error of the actual speed vm with respect to the model speed vr is reduced.

[0011]

As described above, in this type of conventional apparatus, control is performed to compensate for an error with respect to disturbance by PI operation. If the inertia of the load machine is large relative to the electric motor, the motor vibrates greatly, causing a problem that the proportional gain Kp and the integral gain Ki cannot be sufficiently increased. However, there is a problem that the actual speed vm cannot be accurately controlled.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. Particularly, even in a case where a mechanical load having low rigidity of a mechanical system and a large inertia as compared with an electric motor is driven, a simple adjustment can be performed. It is an object of the present invention to provide a motor speed control device that realizes control that stably improves control accuracy with respect to disturbance.

[0013]

SUMMARY OF THE INVENTION In view of the above-mentioned object, the present invention provides a first method for inputting a signal containing the actual speed, which is the rotation speed of an electric motor, in a sum element and outputting a signal obtained by filtering low frequency components. And a first control calculation for calculating a low-range torque command based on a sum or a difference between a signal obtained by proportionally multiplying at least the output of the first low-pass filter and a signal based on a speed command for motor speed control. And a second control calculation unit that inputs the low-frequency torque command and the actual speed, and calculates the torque command based on a sum or difference of at least a signal based on a proportional multiple of the actual speed and the low-frequency torque command. A motor speed control device comprising:

[0014] The second control operation unit includes a second low-pass filter that outputs a signal obtained by filtering a low-frequency component of the signal including the actual speed in the sum element, and includes at least the low-frequency torque command and the low-pass torque command. 2. The motor speed control device according to claim 1, wherein the torque command is calculated based on a sum or a difference with a signal obtained by proportionally multiplying an output of the second low-pass filter. 3.

Further, the speed command is input, and a model speed which is a speed of the assumed model of the control object and a model torque which is a torque of the model are calculated and output so that the model speed follows the speed command. The first low-pass filter inputs a difference signal between the model speed and the actual speed and outputs a signal obtained by filtering a low frequency component, and the first control operation unit Calculating a low-frequency torque command based on the sum of a signal obtained by proportionally multiplying the output of the first low-pass filter and a model torque, wherein the second control calculation unit calculates the low-frequency torque command, the model speed, and the actual speed. The speed command is input, and the torque command is calculated by a sum of a signal based on a proportional multiple of a difference signal between the model speed and the actual speed and the low-frequency torque command. In motor speed control.

Further, the second control operation unit includes a second low-pass filter that outputs a signal obtained by filtering a low-frequency component of a difference signal between the model speed and the actual speed, and includes at least the low-frequency torque command and the low-pass torque command. 4. The motor speed control device according to claim 3, wherein the torque command is calculated based on a sum of a signal obtained by proportionally multiplying an output of the second low-pass filter. 5.

5. The motor speed control device according to claim 1, wherein the second control operation unit performs the operation at a higher sampling period than the first control operation unit. It is in.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing a configuration of a motor speed control device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a control object including a motor torque controller, a motor and a mechanical system of a load, and a speed detector (both not shown). Reference numeral 2 denotes a model calculation unit. Reference numeral 3 denotes a first low-pass filter, 4 denotes a first proportional controller, 5 denotes an integral controller, 6 denotes a second low-pass filter, and 7 denotes a second proportional controller. 8 is a low-speed operation unit, and 9 is a high-speed operation unit.
Note that the first proportional controller 4 and the integral controller 5 constitute a first control operation unit, and the second low-pass filter 6 and the second proportional controller 7 constitute a second control operation unit.

Next, the operation will be described. First, the controlled object 1 inputs a torque command qr, and the controlled object 1 internally drives a motor and a mechanical system serving as a load by controlling the torque of the motor so as to match the torque command qr by a torque controller. The speed detector detects the actual speed vm which is the speed of the electric motor. The transfer characteristic from the torque command qr to the actual speed vm is described as G (s).

Next, the operation of the low-speed operation section 8 will be described. The low speed calculation unit 8 inputs the speed command vr input from the outside and the actual speed vm detected by the control target 1. The low-speed operation unit 8 includes a model operation unit 2, a first low-pass filter 3,
It is composed of a first proportional controller 4 and an integral controller 5,
The operation described below is performed.

Next, the model operation unit 2 in the low-speed operation unit 8
The operation of will be described. The model calculation unit 2 receives a speed command vr from outside. Further, a model of the control target 1 is assumed in advance, and a model speed va, which is a model speed, and a model torque qa, which is a model torque, are converted into a model speed v.
The calculation is performed so that a follows the speed command vr. For example, if the model of the control target 1 assumed in the model calculation unit 2 is a rigid machine whose inertia is Ja, the model torque q
Since a is the differential of the model speed va, that is, the model acceleration q multiplied by the model inertia Ja becomes the model torque qa.
The model speed va and the model torque qa are calculated by (2). Hereafter, s represents the Laplace operator.

Va = F (s) · vr (1) qa = J · s · F (s) · vr (2)

Where F (s) is the speed command vr
Is a desired transfer characteristic that causes the model speed va to follow, for example, is set as a low-pass transfer characteristic.

Next, the first low-pass filter 3 receives the difference signal between the model speed va and the actual speed vm, and outputs a signal obtained by performing a transfer function calculation of a predetermined low-pass characteristic (extracting low frequency components). I do. Here, the cutoff frequency of the first low-pass filter 3 is described as ωf1.

Next, the first proportional controller 4 receives the output of the first low-pass filter 3 and outputs a signal multiplied by a first proportional gain Kp1 set in advance.
And outputs a signal integrated by multiplying the output of the low-pass filter 3 by an integral gain Ki set in advance. The low-speed operation unit 8 outputs the output of the first proportional controller 4 and the integral controller 5
Is calculated as the first error compensation torque qc1. That is, the first error compensation torque qc1 is calculated by PI (proportional integration) calculation. The low-speed operation unit 8 outputs a sum signal of the model torque qa and the model speed va calculated by the model operation unit 2 and the first error compensation torque qc1 as a low-frequency torque command qrl.

Next, the operation of the high-speed operation unit 9 will be described. The high-speed calculation unit 9 inputs the low-frequency torque command qrl, the model speed va, and the actual speed vm detected by the control target 1. Further, inside the high-speed operation unit 9, the second low-pass filter 6 inputs a difference signal between the model speed va and the actual speed vm,
A signal obtained by calculating a transfer function of a low-pass characteristic of a preset cutoff frequency ωf2 is output. Here, the cut-off frequency ωf2 of the second low-pass filter is set to be higher (higher) than the cut-off frequency ωf1 of the first low-pass filter.

Next, the second proportional controller 7 outputs a second proportional gain Kp to the output of the second low-pass filter 6 in advance.
2 is output as a second error compensation torque qc2, and the high-speed calculation unit 9 outputs a sum signal of the low-frequency torque command qrl and the second error compensation torque qc2 as a torque command qr, and outputs the torque command qr. The mechanical system of the controlled object 1 is driven by inputting to the controlled object 1.

Here, the high-speed operation unit 9 performs the operation at a higher sampling period than the low-speed operation unit 8. That is, the update cycle of the values of the actual speed vm and the torque command qr is determined by the model speed va and the model torque q
The calculation is performed such that the update is performed at a cycle faster than the update cycle of a.

The first embodiment is configured as described above, so that the error between the model speed va and the actual speed vm can be reduced by the first speed.
Error compensation torque qc1 and second error compensation torque qc2
The control is performed such that the error is reduced by compensating for the error.

Next, the principle of the effect obtained by the present invention will be described with reference to FIG. In FIG. 2, (a)
Indicates the frequency response of the loop transfer function described below using the conventional technique. (b) shows a frequency response of a transfer characteristic of a feedback unit described later of the motor speed control device of the present invention. (c)
Shows the frequency response of the loop transfer function of the motor speed control device of the present invention. Note that all of these frequency responses are shown in a diagram in which the gain is approximated by a polygonal line.

When the rigidity of the mechanical system of the controlled object 1 is low, mechanical resonance occurs, and the transfer characteristic G (s) of the controlled object 1 has a characteristic having anti-resonance and resonance. Also, considering a two-inertia system in which the two inertia of the motor and the mechanical load are connected by a low-rigidity spring for simplicity of explanation, the larger the ratio of the inertia of the mechanical load to the inertia of the motor, the more It has the characteristic that the resonance frequency is separated from the resonance frequency. Here, a case is considered in which only feedback by PI calculation as in the related art is performed on the control target 1 and the control gain is set to a certain value.

That is, in the configuration of the first embodiment, the second proportional gain Kp2 of the second proportional controller 7 is set to 0.
Considering the case where the cutoff frequency ωf1 of the first low-pass filter 3 is increased to infinity, the frequency response of the gain of the loop transfer function in this case is represented by a line-line approximation.
(A) of FIG. Here, the loop transfer function is obtained by connecting the transfer characteristic G (s) of the controlled object 1 and the transfer characteristic of the feedback unit of the control device (the transfer characteristic from the actual speed vm to the torque command qr in the calculation of the control device) in series. It is a characteristic.
In the display in FIG. 2, it is assumed that the integral gain Ki of the integral controller 5 is set small for the sake of simplicity.
Ignore and display.

As shown in FIG. 2A, when the ratio of the inertia of the mechanical load to the inertia of the motor is large, the anti-resonance frequency and the resonance frequency are separated, so that the gain of the loop transfer function is large at a high frequency. Have the following characteristics: In addition, when the gain setting of the controller is appropriately performed, a plurality of cross frequencies at which the gain of the loop transfer function crosses 0 [dB] appear as shown in FIG.

Of the plurality of cross frequencies, the cross frequency lower than the anti-resonance frequency is defined as the first cross frequency ωc
1. If the crossover frequency on the higher frequency side than the resonance frequency is expressed as a second crossover frequency ωc2, the first crossover frequency ωc1 is the speed of response (disturbance) at which the actual speed vm converges to the disturbance applied to the controlled object 1. Response speed), and by increasing the gain of the controller as much as possible to increase the first crossover frequency ωc1, the disturbance suppression effect can be increased. On the other hand, in order to control the control system so that it does not diverge due to vibration, at the second crossover frequency ωc2,
The phase delay of the loop transfer function must be small.

However, since the controller has a phase delay caused by the sampling period, the second crossover frequency ωc2
Cannot be made too large, and as a result, in FIG.
If the simple PI control as shown in FIG. 7A is used, the first crossover frequency ωc1 must also be set small.

Also, when a low-pass filter is added to the feedback by the PI operation described in the prior art in order to reduce the gain in the high frequency region of the loop transfer function, that is, in the first embodiment, the second
The second proportional gain Kp2 of the proportional controller is set to 0,
The cut-off frequency ωf1 of the low-pass filter 3 of FIG.
If the setting is made so as to cut off the frequency region higher than the first crossover frequency ωc1 in (a), the gain is reduced in the frequency region higher than the cutoff frequency ωf1 of the first low-pass filter, but the phase is delayed.

As a result, if the peak of the gain of the loop transfer function at the resonance frequency exceeds 0 [dB], the control system vibrates at the resonance frequency and becomes unstable. Therefore, it is necessary to set the gain of the loop transfer function small so that the peak of the gain of the loop transfer function does not exceed 0 [dB], and the first crossover frequency ωc1 must be reduced.

Therefore, in order to set the first crossover frequency ωc1 as large as possible in a stable control system, the phase lag of the loop transfer function at the resonance frequency must be increased without increasing the phase delay.
It is necessary to reduce the gain of the loop transfer function higher than the first crossover frequency ωc1.

On the other hand, the transmission characteristic of the feedback section (the transmission characteristic from the actual speed vm to the torque command qr) when the gain is appropriately set for the control target 1 by the motor speed control device of the present invention. 2 (b) is shown in FIG. FIG. 2C shows the frequency response (gain line diagram) of the loop transfer function in this case. In addition, the integral gain Ki is ignored because it is small. As shown in FIG. 2B, the transfer characteristic of the feedback unit is set to be small on the high frequency side as a whole, and is set not to be a simple low-pass characteristic but to make the gain close to flat near the resonance frequency. This makes it possible to reduce the phase delay near the resonance frequency, and to stably control even if the gain becomes larger than 0 [dB] near the resonance frequency of the loop transfer function.

The difference between the first crossover frequency ωc1 and the second crossover frequency ωc2 can be reduced, and the second crossover frequency ωc
Even if c2 cannot be made too large, the first crossover frequency ω
It is possible to increase c1 to increase the response to disturbance.

Further, in an actual mechanical system, a resonance mode may be present in a frequency region higher than the main resonance frequency shown in FIG. 2, so that the gain in the frequency region higher than the second crossover frequency ωc2 is , The second low-pass filter 6
By reducing high frequency components, it is possible to improve stability against such high mechanical resonance. If there is no mechanical resonance in a frequency region higher than the main mechanical resonance, the second proportional controller 7 outputs the difference signal between the model speed va and the actual speed vm without using the second low-pass filter 6. May be entered.

As a procedure for adjusting the control system, first, the cutoff frequency of the second low-pass filter is set higher than the resonance frequency, and then the second proportional gain Kp2 is increased as much as possible in a range where the control system is stable. After that, if the response to the disturbance is not sufficiently fast, that is, if the first crossover frequency ωc1 is small, the target first crossover frequency ωc
Good adjustment of the control system can be realized by a simple procedure of setting the cutoff frequency ωf1 of the first low-pass filter to a value slightly larger than 1 and increasing the first proportional gain Kp1. The integral gain Ki may be set as appropriate.

Further, as described above, since it is necessary to reduce the phase delay of the transfer characteristic of the feedback section, it is preferable to reduce the phase delay caused by the sampling period of the control device to obtain a mechanical resonance in a wider frequency range. However, if all the calculations of the control system described above are performed in a single sample period, it is difficult to shorten the sample period because the amount of calculation is large.

However, the transfer characteristic of the feedback section in the frequency region higher than the zero point frequency ωz in the gain line diagram shown in FIG. 2B is the characteristic calculated by the second low-pass filter and the second proportional controller. Since it becomes dominant, only the operation of the high-speed operation unit 9 including the second low-pass filter and the second proportional controller is operated at a high-speed sample period, thereby reducing the phase delay caused by the sample period in the high-frequency region. It becomes possible to do.

The first embodiment of the present invention is configured as described above, and includes a first low-pass filter 3 and a first proportional controller 4.
And a high-speed operation unit 9 including a second low-pass filter 6 and a second proportional controller 7. The gain of the loop transfer function is set in the high-frequency region as described above. In order to prevent the phase from being delayed as much as possible at the resonance frequency while reducing, it is possible to improve the effect of suppressing disturbance by simple adjustment without deteriorating the stability. In addition, stable control can be performed even when mechanical resonance exists in a frequency region higher than the main mechanical resonance.

Further, the operation of the high-speed operation unit 9 composed of the second low-pass filter 6 and the second proportional controller 7 is performed at a higher sampling period than the low-speed operation unit 8, so that a wider range of machines can be obtained. It is possible to stably improve the disturbance suppressing effect on the resonance.

Further, the apparatus further comprises a model calculating section 2 for calculating a model speed va and a model torque qa calculated by the model calculating section, and a first error compensation calculated based on a difference signal between the model speed va and the actual speed vm. Torque qc1 and model torque q
a low-frequency torque command qrl, and a sum signal of the second error compensation torque qc2 calculated based on the difference signal between the model speed va and the actual speed vm and the low-frequency torque command qrl is a torque command qr. Therefore, in a low frequency region where the control target 1 is approximated to a rigid body, the error between the model speed va and the actual speed vm with respect to the speed command vr can be controlled to be small.

Embodiment 2 FIG. 3 shows a configuration of a motor speed control device according to Embodiment 2 of the present invention. In the drawing, 13 is a first low-pass filter, 14 is a first proportional controller, 15 is an integral controller, 16 is a second low-pass filter, 17 is a second proportional controller, 18 is a low-speed operation unit,
9 is a high-speed operation unit. Note that the first proportional controller 14 and the integral controller 15 constitute a first control operation unit,
The low-pass filter 16 and the second proportional controller 17 constitute a second control operation unit.

Next, the operation will be described. First, the first low-pass filter 13, the first proportional controller 14, the integral controller 1
5 will be described. The low speed calculation unit 18 receives the speed command vr and the actual speed vm.
Next, the first low-pass filter 13 inputs the actual speed vm inside the low-speed operation unit 18 and outputs a signal obtained by performing a transfer function operation of a preset low-pass characteristic.

Next, the first proportional controller 14 receives the output of the first low-pass filter 13 and outputs a signal multiplied by a first proportional gain Kp1 set in advance. Next, the integration controller 15 inputs a difference signal between the speed command vr and the output of the first low-pass filter 13 and sets a predetermined integration gain Ki.
, And outputs a signal integrated.
The difference signal between the output of the proportional controller 14 and the output of the integral controller 15 is output as the low-frequency torque command qrl.

Here, the low-speed operation unit 18 uses the signal passed through the first low-pass filter 13 for the actual speed vm,
This means that control generally called control is performed.

Next, the high-speed operation unit 19 receives the actual speed vm and the low-frequency torque command qrl. Inside the high-speed operation unit 19, the second low-pass filter 16 receives the actual speed vm and calculates the transfer function of the low-pass characteristic. Is output, the second proportional controller 17 outputs a signal obtained by multiplying the output of the second low-pass filter 16 by a preset second proportional gain Kp2, and the high-speed operation unit 19 outputs The difference signal between the output of the proportional controller 17 and the low range torque command qrl is
Is output as Then, the high-speed operation unit 19 outputs the torque command qr
Is input to the control target 1 to drive the mechanical system of the control target 1.

The sample period of the operation of the high-speed operation unit 19 is calculated faster than the sample period of the operation of the low-speed operation unit 18.

Instead of applying the speed command vr to the input side of the integral controller 15, the input of the first low-pass filter 13 may be a difference signal between the speed command vr and the actual speed vm as shown in FIG. This corresponds to performing the PI control to which the low-pass filter is added in the low-speed operation unit 18. In this case, the low-speed operation unit 18 obtains the sum signal of the output of the first proportional controller 14 and the output of the integration controller 15 and outputs this as a low-range torque command qrl. A sum signal of the output of the second proportional controller 17 and the low-frequency torque command qrl is output as a torque command qr.

Since the second embodiment is configured as described above, it does not include the model calculation unit 2 in the first embodiment, and has a simple configuration based on IP control. The response of the actual speed vm to vr cannot be set too fast. However, the transfer characteristic of the feedback unit (actual speed vm in the calculation of the control device)
Since the transmission characteristics from the torque command qr to the torque command qr) are exactly the same as those in the first embodiment, the effect of improving the disturbance suppression effect is exactly the same as in the first embodiment.

[0056]

As described above, according to the first aspect of the present invention, a signal including an actual speed, which is the rotation speed of a motor, in a sum element and outputting a signal obtained by filtering a low frequency component is output. A first low-pass filter, and a first control for calculating a low-frequency torque command based on a sum or difference of at least a signal obtained by proportionally multiplying the output of the first low-pass filter and a signal based on a speed command for motor speed control. A second control calculation for inputting the low-frequency torque command and the actual speed, and calculating the torque command based on a sum or difference of at least a signal based on a proportional multiple of the actual speed and the low-frequency torque command; The motor speed control device is characterized by having a unit, so that the frequency response of the loop transfer function can be reduced at high frequency gain with a small phase delay near the resonance frequency of the controlled object, and simple adjustment can be performed. , It is possible to improve the disturbance suppression effect by setting fast response to the disturbance.

According to a second aspect of the present invention, in the first aspect, the second control operation unit outputs a signal obtained by filtering a low frequency component of a signal including the actual speed in a sum element.
And a low-pass filter for calculating the torque command based on the sum or difference of at least the low-frequency torque command and a signal obtained by proportionally multiplying the output of the second low-pass filter. Therefore, even when mechanical resonance exists in a frequency region higher than the main mechanical resonance, it is possible to stably improve the disturbance suppression effect.

According to a third aspect of the present invention, in the first aspect, the speed command is input, and the model speed, which is the assumed speed of the model of the controlled object, and the model torque, which is the torque of the model, are set as the model speed. A model calculation unit that calculates and outputs the speed command so as to follow the speed command, wherein the first low-pass filter receives a difference signal between the model speed and the actual speed and filters a low-frequency component; The first control calculation unit calculates a low-frequency torque command based on the sum of a model torque and a signal obtained by proportionally multiplying the output of the first low-pass filter, and the second control calculation unit calculates The low-frequency torque command, the model speed, and the actual speed are input, and the torque command is calculated by the sum of a signal based on a proportional multiple of a difference signal between the model speed and the actual speed and the low-frequency torque command. The frequency response of the loop transfer function can be reduced while maintaining a small phase lag near the resonance frequency of the controlled object, and the high-frequency gain can be reduced. The disturbance suppression effect can be improved, and the response of the actual speed to the speed command can be controlled quickly and with high accuracy.

According to a fourth aspect, in the third aspect, the second control operation section outputs a signal obtained by filtering a low frequency component of a difference signal between the model speed and the actual speed. A motor speed control device including a low-pass filter and calculating the torque command based on at least a sum of the low-frequency torque command and a signal obtained by proportionally multiplying the output of the second low-pass filter. Even if mechanical resonance exists in a frequency region higher than the mechanical resonance, it is possible to stably improve the disturbance suppression effect,
The response of the actual speed to the speed command can be controlled quickly and with high accuracy.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the second control operation unit performs the operation at a higher sampling period than the first control operation unit. As a result, the phase delay caused by the sample period can be reduced in the high frequency range, and the disturbance suppression effect can be improved stably with respect to mechanical resonance in a wider frequency range. is there.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining a frequency response of a control system according to the present invention and the prior art.

FIG. 3 is a diagram showing a configuration of a motor speed control device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of another motor speed control device according to Embodiment 2 of the present invention.

FIG. 5 is a diagram showing a configuration of a conventional motor speed control device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 control target, 2 model operation unit, 3 first low-pass filter, 4 first proportional controller, 5 integral controller, 6
Second low-pass filter, 7 second proportional controller, 8
Low-speed operation unit, 9 high-speed operation unit, 13 first low-pass filter, 14 first proportional controller, 15 integration controller,
16 second low-pass filter, 17 second proportional controller, 18 low-speed operation unit, 19 high-speed operation unit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Araki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Tetsuya Nishio 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F term in Ryo Denki Co., Ltd. (reference) 3F002 DA08 EA01 EA05 5H004 GA07 GA09 GB20 HA08 HB08 KA65 KB02 KB03 KB04 KB22 KB30 KC34 LA13 LA20 MA12 5H550 AA07 AA18 BB05 BB08 GG03 JJ04 JJ24 JJ26 LL01

Claims (5)

[Claims] 1. A first low-pass filter for inputting a signal including the actual speed, which is the rotation speed of an electric motor, in a sum element and outputting a signal obtained by filtering a low-frequency component, and at least an output of the first low-pass filter A first control calculation unit that calculates a low-frequency torque command based on the sum or difference between a signal obtained by multiplying the low-frequency torque command and a signal based on a speed command for motor speed control; An electric motor speed control device comprising: a second control operation unit that calculates the torque command based on a sum or difference between a signal based on at least a proportional multiple of the actual speed and the low-frequency torque command. A second low-pass filter that outputs a signal obtained by filtering a low-frequency component of a signal that includes the actual speed in a sum element, wherein the second control operation unit includes at least the low-frequency torque command and 2. The motor speed control device according to claim 1, wherein the torque command is calculated based on a sum or a difference with a signal obtained by proportionally multiplying an output of the second low-pass filter. 3. 3. The speed command is input, and a model speed which is an assumed speed of a model of a control target and a model torque which is a torque of the model are calculated and output so that the model speed follows the speed command. The first low-pass filter receives the difference signal between the model speed and the actual speed and outputs a signal obtained by filtering a low-frequency component. Calculating a low-frequency torque command based on a signal obtained by proportionally multiplying the output of the first low-pass filter and a model torque, wherein the second control calculation unit calculates the low-frequency torque command, the model speed, and the actual speed. The speed command is input, and the torque command is calculated by a sum of a signal based on a proportional multiple of a difference signal between the model speed and the actual speed and the low-frequency torque command. Motive speed control device. 4. The second control calculation unit includes a second low-pass filter that outputs a signal obtained by filtering a low-frequency component of a difference signal between the model speed and the actual speed, and includes at least the low-frequency torque command and The motor speed control device according to claim 3, wherein the torque command is calculated based on a sum of a signal obtained by proportionally multiplying an output of the second low-pass filter. 5. The motor speed control device according to claim 1, wherein the second control operation unit performs the operation at a higher sampling period than the first control operation unit. .