JP7294237B2 - motor speed controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a speed control device for an electric motor, and more particularly to a speed control device for an electric motor that drives a winder.

As described in Patent Document 1, a winder in a rolling facility for wire rods, steel bars, thin plates, etc. is required to stop at a fixed position with high accuracy. Speed control of the electric motor driving the winder is required to stop the winder at a fixed position. However, the winding machine has the characteristic that the diameter of the coil increases as the winding progresses, and the ^GD2 of the coil increases according to the coil diameter, as shown in FIG. Therefore, in the winding machine, speed control of the electric motor corresponding to GD ² of the coil is required. The following Patent Documents 2 to 5 can be exemplified as prior art documents related to speed control of an electric motor. In this specification, the moment of inertia is expressed as "GD ² ", which is the expression format in the gravitational unit system.

JP-A-59-150617 JP-A-62-147716 JP-A-1-075349 JP-A-1-089983 Japanese Utility Model Laid-Open No. 63-162752

Proportional integral control is generally used to control the speed of the electric motor that drives the winder. In proportional-integral control, the control characteristics change depending on the settings of the proportional gain and the integral gain. FIG. 6 shows an example of proportional gain and integral gain settings in motor speed control. One means of maintaining velocity control responsiveness despite changes in coil ^GD2 is to increase the proportional gain as ^GD2 increases, as shown in FIG. However, since there is a limit to the device, if the proportional gain is too large, the speed control will cause hunting. In order to prevent hunting, the overall proportional gain should be lowered, but if the proportional gain is too small, the response of speed control will become slow. In other words, if hunting is to be prevented at the maximum set value B0 of the proportional gain, the responsiveness of the speed control becomes dull at the minimum set value A0 of the proportional gain. Conversely, if an attempt is made to improve the responsiveness of the speed control at the minimum set value A0 of the proportional gain, hunting will occur at the maximum set value B0 of the proportional gain.

Therefore, in conventional motor speed control, as shown in FIG. 7, the proportional gain is increased stepwise according to the increase in ^GD2 , and the integral gain is decreased stepwise in accordance with the increase in the proportional gain. has been done. In the example shown in FIG. 8, the proportional gain and the integral gain each have four set values, and the gains are switched according to GD ² with gain switching numbers 0 to 3. The gain switching number is set so that the ^GD2 value is divided into regions of 0-3. By setting the proportional gain and the integral gain in this manner, it is possible to prevent the proportional gain from becoming excessively large.

8, 9, and 10 are speed control response diagrams showing the relationship between the speed command value and the speed feedback value. A speed feedback value means an actual value of the winding speed (m/s) measured by a sensor. FIG. 11 is a diagram showing the relationship between the waveforms of the speed command value and the speed feedback value when the winding machine with the coil mounted thereon is stopped. Problems in conventional speed control of an electric motor will be described below with reference to these figures.

FIG. 8 shows an ideal relationship between a speed command value and a speed feedback value that can realize highly accurate speed control. If the set value of the proportional gain is appropriate, the responsiveness shown in FIG. 8 can be achieved, and high fixed-position stopping accuracy can be achieved as indicated by the speed feedback value 1 in FIG. On the other hand, when the set value of the proportional gain is larger than the appropriate value, the speed feedback value peaks out as shown in FIG. 9, and the speed command value is not easily reached. When the winder is stopped by such responsive speed control, it takes time to stop the winder, as indicated by the speed feedback value 2 in FIG. Conversely, when the set value of the proportional gain is smaller than the proper value, the speed feedback value overshoots the speed command value as shown in FIG. When the winder is stopped by such responsive speed control, the speed of the winder once becomes zero, and then the winder rotates in the reverse direction and then stops, as indicated by the speed feedback value 3 in FIG. In other words, in this case, the winder overshoots the set stop position and unwinds the coil.

However, it is desirable to avoid unwinding the coil. In actual adjustment in conventional speed control of an electric motor, a coil having the maximum coil diameter is mounted on the winding machine, and the set value B of the proportional gain shown in FIG. is adjusted. Also, the integral gain is adjusted according to the set value B of the proportional gain. Then, based on the adjusted set value B of the proportional gain and the integral gain, the proportional gain and the integral gain at the maximum GD ² in the region of the gain switching number 0 are adjusted. At this time, the set value A of the proportional gain is adjusted so that the set value A of the proportional gain does not become too small, that is, the speed response as shown in FIG. 8 is obtained. Further, the proportional gain and the integral gain at the maximum ^GD2 in the area of the gain switching number 1, and the proportional gain and the integral gain at the maximum ^GD2 in the area of the gain switching number 2 are set respectively.

By setting the proportional gain and integral gain as described above, the proportional gain does not become too small with respect to ^GD2 . As a result, an overshoot-like speed response such as that shown in FIG. 10 does not occur, and a situation in which the coil is unwound due to overshooting of the stop position is avoided. However, instead of that, as shown in FIG. 9, there occurs a point where the speed feedback value peaks out with respect to the speed command value. In the area of gain switch number 3, the proportional and integral gains in this area are adjusted based on GD ² of the largest coil. Therefore, at a point where GD2 is smaller than ^GD2 of the largest coil immediately after switching from the area of gain switching number ² to the area of gain switching number 3, the proportional gain becomes excessively large with respect to ^GD2 . At a point where the proportional gain is excessively large with respect to ^GD2 , the velocity feedback value peaks out with respect to the velocity command value. For this reason, in the conventional speed control of the electric motor, it takes time to stop the winder, and as a result, the production efficiency of the factory is lowered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is an electric motor capable of suppressing deterioration in speed control accuracy of the electric motor due to fluctuations in the moment of inertia of a coil wound by a winder. It is an object of the present invention to provide a speed control device.

An electric motor speed control device according to the present invention is a device that calculates an operation amount of an electric motor by feedback control so that a speed feedback value of the electric motor coincides with a speed command value of the electric motor. Feedback control includes proportional control and integral control. A motor speed control device according to the present invention includes a proportional gain switching circuit and an integral gain switching circuit. The proportional gain switching circuit is configured to switch the setting of the proportional gain step by step according to an increase in the moment of inertia of the coil wound by the winder. Specifically, the proportional gain switching circuit increases the proportional gain in proportion to the increase in the moment of inertia of the coil, and once decreases the proportional gain when the setting is switched, and then again increases the moment of inertia of the coil. Increase the proportional gain proportionally. In addition, the proportional gain switching circuit is proportional to the increase in the moment of inertia of the coil so that the maximum value of the proportional gain after switching the setting is larger than the maximum value of the proportional gain before switching the setting. Gain may be increased. The integral gain switching circuit is configured to decrease the integral gain stepwise in accordance with the switching of the setting of the proportional gain.

According to the speed control device for a motor according to the present invention, the speed control of the motor can be performed with proper proportional gain and integral gain regardless of the value of the moment of inertia of the coil. As a result, the accuracy of stopping at a fixed position in the winding machine can be improved.

FIG. 4 is a diagram showing gain switching numbers and setting of proportional gain and integral gain for GD ² in an embodiment of the present invention together with a coil image; It is a figure which shows the relationship between ^GD2_x and Px. It is a diagram showing the configuration of a proportional gain switching circuit according to the embodiment of the present invention. It is a diagram showing a configuration of an integral gain switching circuit according to the embodiment of the present invention. FIG. 4 is a diagram showing the relationship between coil diameter and ^GD2 . FIG. 10 is a diagram showing a gain switching number, a proportional gain and an integral gain setting for GD ² in conventional control, together with a coil image. FIG. 10 is a diagram showing a gain switching number, a proportional gain and an integral gain setting for GD ² in conventional control, together with a coil image. FIG. 4 is a velocity response diagram showing the relationship between a velocity command value and a velocity feedback value; FIG. 4 is a velocity response diagram showing the relationship between a velocity command value and a velocity feedback value; FIG. 4 is a velocity response diagram showing the relationship between a velocity command value and a velocity feedback value; FIG. 10 is a diagram showing a speed command value and a speed feedback value when the winding machine with the coil mounted thereon is stopped;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, when referring to numbers such as the number, quantity, amount, range, etc. of each element in the embodiments shown below, unless otherwise specified or clearly specified in principle, the reference The present invention is not limited to this number. Also, the structures and the like described in the embodiments shown below are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant description thereof will be appropriately simplified or omitted.

The speed control device according to the present embodiment is a speed control device for an electric motor that drives a winding machine (winding machine) in rolling equipment for wire rods, steel bars, thin plates, etc., and a speed feedback value is added to the speed command value of the electric motor. It is a device that calculates the operation amount of the electric motor by proportional integral control so as to match. A speed command value is a command value transmitted from a higher control device. The speed feedback value is the actual winding speed measured by the sensor. The speed control device according to the present embodiment switches the proportional gain and the integral gain of the proportional-integral control step by step according to the ^GD2 of the coil, which increases as the winding progresses.

FIG. 1 is a diagram showing the setting of the gain switching number, the proportional gain and the integral gain for the GD ² in this embodiment together with the coil image. As shown in FIG. 1, the proportional gain and the integral gain are each switched in four stages according to the increase of ^GD2 .

According to the speed control device according to the present embodiment, the proportional gain is increased in proportion to the increase in ^GD2 before the setting is switched. When the settings are switched, that is, when the gain switching number is switched, the proportional gain is once lowered and then increased again in proportion to the increase in the moment of inertia of the coil. The maximum value of the proportional gain after switching the setting is greater than the maximum value of the proportional gain before switching the setting. For example, the maximum value of the proportional gain in the region of gain switching number 3 is greater than the maximum value of the proportional gain in the region of gain switching number 2 . On the other hand, the integral gain is lowered stepwise each time the gain switching number is switched. By decreasing the integral gain each time the gain switching number changes to slow down the speed response, it is possible to prevent the proportional gain from becoming excessively large.

A proper proportional gain value corresponding to the changing ^GD2 is calculated by the following equation (1). If the proportional gain P changes in a proportional relationship with ^GD2 as shown in the following equation (1) and always stays at an appropriate value, an ideal velocity response as shown in FIG. 8 can be obtained. Then, when the winding machine is stopped, it is possible to achieve a highly accurate fixed position stop such as the speed feedback value 1 shown in FIG.
P= ^GD2 / ^GD2_x *Px (1)
however,
P: Proportional gain value ^GD2 [kg·m2]: Current coil ^GD2 value including mechanical system ^GD2_x [kg·m2]: ^GD2 value when Px is adjusted Px: ^GD2 Value of proportional gain adjusted by _x

FIG. 2 is a diagram showing the relationship between GD ² —x and Px in Equation (1) above. GD ² _0, which is the minimum value of GD ² in FIG. 2, is set to the GD ² value of the winder including the motor, brake, gear, and the like. GD ² _0 is added to the value of GD ² of the coil sent from the master control device to the speed control device, which is GD ² on the vertical axis of FIG. ^GD2 . Hereinafter, the ^GD2 of the current coil including the mechanical system is referred to as the total ^GD2 .

GD ² _1 is the total GD ² value at the point where gain switching number 0 is switched to gain switching number 1 . P1 is a proportional gain adjusted to obtain a velocity response as shown in FIG. 8 at GD ² _1. P1 corresponds to the set value A of the proportional gain in conventional speed control. In the area of the gain switching number 0, the proportional gain P corresponding to the total GD 2 is calculated by multiplying the ratio between the total GD ² and GD ² — ¹ by P1 according to the above equation (1).

GD ² _2 is the total GD ² value at the point where gain switching number 1 is switched to gain switching number 2 . P2 is a proportional gain adjusted to obtain a velocity response as shown in FIG. 8 at GD ² _2. In the region of gain switching number 1, the proportional gain P corresponding to the total GD 2 is calculated by multiplying the ratio between the total GD ² and GD ² — ² by P2 according to the above equation (1).

GD ² _ 3 is the total GD ² value at the point of switching from gain switching number 1 to gain switching number 2 . P3 is a proportional gain adjusted to obtain a velocity response as shown in FIG. 8 at GD ² _3. In the region of gain switching number 2, the proportional gain P corresponding to the total GD ² is calculated by multiplying the ratio of the total GD ² and GD ² — 3 by P3 according to the above equation (1).

^GD2_4 is the value of ^GD2 at the maximum coil diameter. P4 is a proportional gain adjusted to obtain a velocity response as shown in FIG. 8 at GD ² _4. P4 corresponds to the set value B of the proportional gain in conventional speed control. In the region of gain switching number 3, the proportional gain P corresponding to GD ² is calculated by multiplying the ratio between GD ² and GD ² — 4 by P4 according to the above equation (1).

FIG. 3 is a diagram showing the configuration of a proportional gain switching circuit provided in the speed control device according to this embodiment. The proportional gain switching circuit has storage units 6-14. The values of GD ² _0 to GD ² _4 are stored in the storage units 6 to 10, respectively. The values of P1 to P4 are stored in the storage units 11 to 14, respectively.

The proportional gain switching circuit has comparators 17-20. Each of the comparators 17 to 20 receives the sum of GD ² _0 stored in the storage unit 6 and GD ² L1 input to the input unit 5, that is, the total GD ² . GD ² L1 is the coil GD ² value sent from the master controller to the speed controller. The master controller calculates GD ² L1 from, for example, the winding time and winding diameter of the coil.

Comparator 17 passes the value when total ^GD2 is less than ^GD2_1 . The total ^GD2 passed through the comparator 17 is divided by ^GD2_1 , and the ratio of the total ^GD2 and ^GD2_1 is multiplied by P1. The calculation result is output from the output section 15 as a proportional gain. When comparator 17 passes a value, switch 21 is turned on. When the switch 21 is turned on, the gain switching number 0 is output from the output section 16 .

Comparator 18 passes when total ^GD2 is greater than or equal to ^GD2_1 and less than ^GD2_2 . The total ^GD2 passed through the comparator 18 is divided by ^GD2_2 , and the ratio of the total ^GD2 and ^GD2_2 is multiplied by P2. The calculation result is output from the output section 15 as a proportional gain. When comparator 18 passes a value, switch 22 is turned on. When the switch 22 is turned on, the gain switching number 1 is output from the output section 16 .

Comparator 19 passes when total ^GD2 is greater than or equal to ^GD2_2 and less than ^GD2_3 . The total ^GD2 passed through the comparator 19 is divided by ^GD2_3 , and the ratio of the total ^GD2 and ^GD2_3 is multiplied by P3. The calculation result is output from the output section 15 as a proportional gain. When comparator 19 passes a value, switch 23 is turned on. When the switch 23 is turned on, the gain switching number 2 is output from the output section 16 .

Comparator 20 passes a value when total ^GD2 is greater than or equal to ^GD2_3 . The total ^GD2 passed through the comparator 20 is divided by ^GD2_4 , and the ratio of the total ^GD2 and ^GD2_4 is multiplied by P4. The calculation result is output from the output section 15 as a proportional gain. When comparator 20 passes a value, switch 24 is turned on. When the switch 24 is turned on, the gain switching number 3 is output from the output section 16 .

FIG. 4 is a diagram showing the configuration of an integral gain switching circuit included in the speed control device according to this embodiment. The integral gain switching circuit has storage units 25 to 28 that store integral gain setting values. The storage unit 25 stores Group 0 including the integral gain when the gain switching number is 0. FIG. The storage unit 26 stores Group 1 including the integral gain when the gain switching number is 1. FIG. The storage unit 27 stores Group 2 including the integral gain when the gain switching number is 2. FIG. The storage unit 28 stores Group 3 including the integral gain when the gain switching number is 3. FIG.

The gain switching number output from the proportional gain switching circuit is input to the input section 16 . One of Groups 0 to 3 is selected according to the gain switching number input to the input unit 16 . Then, the integral gains included in the selected Groups 0 to 3 are output from the output section 29 . In addition to the integral gain, an anti-overshoot gain, a speed filter, a torque filter, etc. can also be set for each of Groups 0-3.

By providing the speed control device with the proportional gain switching circuit having the configuration shown in FIG. 3, setting of the proportional gain for GD ² (total GD ² ) shown in FIG. 1 is realized. Also, by providing the integral gain switching circuit having the configuration shown in FIG. 4 in the speed control device, setting of the integral gain for the gain switching numbers shown in FIG. 1 is realized. According to the proportional gain and the integral gain set in this way, it is possible to suppress the deterioration of the precision of the speed control of the electric motor due to the variation of the ^GD2 of the coil. As a result, the accuracy of stopping at a fixed position in the winding machine can be improved.

5 Input section 6 to 10 Storage section 11 to 14 for GD ² _x Storage section 15 for Px Output section 16 for proportional gain calculation result Output section for gain switching number 17 to 20 Comparator 21 to 24 Switch 25 to 28 Integral gain setting value Storage unit 29 Output unit for integral gain calculation result

Claims (2)

A speed control device for an electric motor that calculates the operation amount of the electric motor by feedback control including proportional control and integral control so that the speed feedback value of the electric motor matches the speed command value of the electric motor that drives the winder,
a proportional gain switching circuit that switches the setting of the proportional gain in stages according to an increase in the moment of inertia of the coil wound by the winding machine;
an integral gain switching circuit that reduces the integral gain stepwise in accordance with the switching of the setting of the proportional gain,
The proportional gain switching circuit increases the proportional gain in proportion to the increase in the moment of inertia of the coil, and once decreases the proportional gain when switching the setting, and then again responds to the increase in the moment of inertia of the coil. A speed control device for an electric motor, wherein the proportional gain is increased in a proportional relationship. The proportional gain switching circuit has a proportional relationship with the increase in the moment of inertia of the coil so that the maximum value of the proportional gain after switching the setting is larger than the maximum value of the proportional gain before switching the setting. 2. A speed control device for an electric motor according to claim 1, wherein said proportional gain is increased by .

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