JPS6277897A - Motor for controlling tension of rolling mill - Google Patents

Abstract

PURPOSE:To improve the reliability notably by eliminating a sleeve contact by a method wherein, in a motor for driving a rooper, a rotor is connected to a power supply through a power cable moderately slackened. CONSTITUTION:Terminals 7b1 of a rotor winding 7b are led out of the end reverse to directly connected axle side through a central hole 7f1 excavated at the central part of a rotary axle 7f. The terminals 7b1 led out by a flexible conductor made of mild copper wire or connected to a power cable moderately slackened are constituted to make a rotor free-rotatable within the range of 180 deg.. In such a constitution, the titled motor though similar to a winding induction motor can eliminate a sleeve contact part comprising a slip ring and a brush.

Description

DETAILED DESCRIPTION OF THE INVENTION (Description of Technical Field) The present invention relates to a rolling tension control electric motor device for controlling inter-stand tension in a metal rolling hall.

[Technical failure of the invention and its problems] In rolling equipment for ferrous and non-ferrous metals, in which a large number of rolling mills are installed close to each other and the material to be rolled is continuously rolled, the rotational speed difference between the rolls of each rolling mill is Due to differences in elongation due to changes in the temperature of the material to be rolled, tension fluctuations occur in the material to be rolled between the rolling mill stands. This tension fluctuation causes unevenness in the thickness of the rolled material during rolling, which increases dimensional errors in the final product and causes defective products. Therefore, the tension of the rolled material between the rolling mill stands should always be constant. controlled by.

There are several conventional methods for controlling this tension.
In particular, a tension control device called an electric looper is sometimes used in a hot pressure 5i facility for rolling a material to be rolled.

As an example of this, as shown in FIG. 7, one louver roller 3 is installed between adjacent rolling mill stands 1.2 to push up the rolled material 4 to an appropriate height. is driven by an electric motor 7 via a link 5 and a gear 6, and the tension acting on the material to be rolled is controlled by changing the height of the looper roller 3.

Characteristics required for such a tension control device include fast response and good controllability. For this reason, conventional electric loopers use DC motors with good secondary leg performance, and in order to improve coordination, motors with as small a moment of inertia as possible are used.

However, as mentioned above, in the system using the gear 6, the moment of inertia of the gear 6 itself is large, which reduces the coordination. l
i2I was damaged due to backlash in gear 6.
Recently, this gear 6 has been eliminated and the IJ link 5 shown in Fig.
An electric louver with a direct drive system has been adopted in which the drive shaft of the IF motor is directly connected to the drive shaft J axis of the IF motor.

Since this type of electric looper used a conventional DC motor as an electric IJ machine, a new problem became a major problem. That is, as is clear from the M construction in Fig. 8, the electric filter 7 directly connected to the drive shaft of the link 5 does not require rotation of more than 60 to 90 degrees in normal equipment. However, under steady operating conditions, it only rotates within a range of 10 to 20 degrees.As is well known, a commutator and brushes are essential for a DC electric shovel, but as mentioned above, For this commutator, rotation within a narrow range is equivalent to energization while the commutator is at rest.

The commutator pieces of a DC electric VJ machine have a structure in which a large number of commutator pieces made of copper or its alloy and thin insulating plates made of an insulator such as mica are arranged alternately in the circumferential direction. Heat conduction in the circumferential direction is extremely poor. When a DC motor with a commutator of this nature is used in a nearly stationary state, only the commutator pieces under the brushes are heated and expand at the circumferential edge, pushing adjacent commutator pieces in the circumferential direction. With,
It extends upward in the radial direction. Also, when the current stops and the commutator cools down, some of the pieces remain stretched upward, and some of the gaps between adjacent commutator pieces become larger than before they were stretched upward. , so-called hyper-rover occurs, such as sinking more toward the center of the radius than in the initial state. These hypers and ropers prevent the brushes from smoothing and sliding, which can cause breakage of the brushes and rough damage to the commutator surface due to generation of large sparks.

In particular, in the case of a gearless system, the torque cannot be increased by gears as in the past, so the required torque of the electric motor increases, and along with this, it becomes necessary to increase the current as well. Countermeasures must be taken, such as creating a very long commutator or dividing the motor into two or more motors and connecting them directly to the -shaft. For this reason, the electric #J gate became larger,
There were problems such as the need for a large space around the rolling mill.

(Object of the Invention) The present invention has been made in order to eliminate the drawbacks of the conventional direct drive type electric looper motor, and an object of the present invention is to provide a rolling mill tension control motor device that does not have a commutator and brushes. purpose.

[Summary of the invention]

In order to achieve the above object, the present invention is constructed as follows. That is, the first invention includes a forward converter that receives AC' power from a commercial frequency AC power source and converts it into variable voltage DC, an inverse converter that switches the direction of current flowing through the rotor winding of a motor, and A first power transformer l! consisting of the controller of said double-degree converter. j! a second device that receives alternating current power from the commercial frequency alternating current power source and converts it into direct current power;
a power converter, and an electric motor having a stator winding that receives power ζ1 from the first power converter and a rotor winding that receives power from the second power converter. It is what it is. Inventions of the second month (Forward converter that receives AC power from a commercial frequency AC power source and converts it to variable voltage DC; Inverse converter that switches the direction of current flowing through the rotor winding of a motor. and a first power converter comprising a controller for the double degree converter, a second power converter that receives AC power from the commercial frequency AC power source and converts it into DC power, and the first power converter. A stator winding receiving power from the device and the second power transformer IIj
! An electric motor equipped with a rotor winding that receives power from equipment E, a rotor rotation angle detection device that detects the rotation angle of the rotor of this motor, and a rotor rotation angle detection device that detects the rotation angle of the rotor of the motor, and detects the rotation angle of the motor according to a signal from the rotor rotation angle detection device. a first function generator that calculates a variation in torque and corrects the current flowing to the stator winding based on the variation; and a first function generator that calculates a variation in torque and corrects the current flowing to the stator winding based on the variation; and a second function generator that corrects the current flowing through the rotor winding according to the magnitude of the current.

[Embodiments of the invention]

First, the basic configuration of a direct drive type rolling mill tension control electric VJ machine device (hereinafter referred to as electric looper device) according to the present invention will be explained.

FIG. 1 shows the main elements constituting the electric looper device according to the present invention. That is, 7 is an electric motor, which consists of stator winding (armature winding) 7c1 rotor winding (field winding, 1) 7b
have. As will be described later, either of the stator 1 rotor windings 7a and 7b may be an armature winding or a field Ef1 winding, and may be a single-use, two-phase, or three-phase winding. However, in Fig. 1, the rotor has a concentrated field winding,
The stator has three winding groups U, V, and W arranged at 120 degrees in electrical angle and connected in a star shape to form a normal three-phase alternating 72-winding structure. The stator winding 7a is connected to the first thyristor power conversion device 8 and receives power supply. Similarly, the rotor winding 7b is connected to the second thyristor power converter 9 and receives power supply.

The first thyristor power converter 8 is a forward converter 8a that receives power from a general commercial AC power source and converts it into DC power.
and smoothing DC reactor (hereinafter referred to as DC reactor)
8b and an inverter 8C that switches the direction of the current flowing through the stator winding 7a of the substation, and a controller 8d that controls the firing timing of the thyristors of the bidirectional converters 3a and 8c.

The second thyristor power conversion device 9 includes a forward converter that receives alternating current power from a commercial power source and converts it into direct current power, and a controller (not shown) for controlling this forward converter.

In FIG. 1, the configuration of the thyristor of the inverse converter 8C of the first thyrisk power conversion wave; N8 is up, vp, wp since the fixed winding is a three-phase winding.

A so-called three-phase Gretz connection consisting of six thyristor groups U, \, VN, and WN is adopted.

FIG. 2 shows a specific configuration of the electric motor 7 mentioned above. The stator winding 7a is housed in a slot provided in the stator core 7C, and is appropriately fixed with a slot pattern, a binding band, etc., as in a normal AC electric motor. 7a is supported by a stator frame 7d.

On the other hand, rotation advance volume 1! Similarly, J7b is accommodated in a slot provided in the rotor core 7e and attached to the rotating shaft 7f. This rotating shaft is connected to a bearing bracket 7h via 7r1 bearings 7c+ and 7(]-.

It is supported by 7h' so that it can rotate freely. Further, the terminal 7b+ of the rotor winding 7b passes through a center hole 7fl provided at the center of the rotating shaft 7f and is led out to the opposite end of the direct connection side.

Usually, the terminal 7b1 is led out by a flexible conductor made of a soft copper wire, or connected by a power cable with an appropriate amount of slack, and has a small structure that allows the rotor to freely rotate within 180 degrees.

The above configuration is similar to a wound type induction electric VJ machine, but what is characteristically different is the lead-out part of the terminal 7b1 of the rotor winding 7b, which is a sliding part consisting of a slip ring and a brush. It has no contact parts.

The operation of the electric looper device configured as above is explained in the third section.
This will be explained with reference to the figures. Second thyristor power change
After converting the commercial AC power into variable voltage DC power using the A unit N9, it is supplied to the rotor winding 7b of the electric wJ Iso, and the electric power f7
A magnetomotive force Φr is generated inside one aircraft.

On the other hand, the first thyristormino converter 8 converts AC power into variable voltage DC power in a forward converter 8a, and then supplies it to an inverse converter 8C via a DC rick 1-8b.

Here, the purpose of the DC reactor 8b is to prevent the DC current flowing through it from intermittent when it is very small. It may be omitted if it does not occur. In the inverter 8C supplied with DC power, the thyristors UP, VP, WP, UN, and VN are activated according to the position of the magnetic pole and the direction of the torque.

’v” Select two appropriate pieces of JN and turn on the electricity for 11 seconds.

FIG. 3 shows a case where two thyristors UP and VN are energized. When the thyristors UP and VN are energized, the stator winding 7a receives a flow of money from the U winding 7.
Direct & current flowing into the winding. This current causes U,
The VS line is the magnetomotive force ΦU.

As a result, the stator lR17a generates its composite magnetomotive force ΦS. Starting f with rotation pre-winding $17b! The force Φr and the magnetomotive force S caused by the stator winding 7a act on each other, and in the direction where their centers coincide, they generate an attractive force and the rotor generates torque.

If the angle formed by the centers of both forces is e, the magnitude of the torque τ is related to τOCΦr・Φ5sine・(11). This is illustrated in FIG. 4, where the magnetomotive force is at its maximum when the center of both magnetomotive forces is at an electrical angle of 90° (or -90').

In a normal direct-coupled electric looper device, electric vJ! l!
The rotation angle of l is 60 to 90 degrees at most, and 20 to 30 inches is sufficient in actual operating conditions.As mentioned above, the motor has two pole windings, so the electrical angle and mechanical angle match. ing.

Therefore, the relative position of the rotor winding 7b and the stator winding 7a in the lowest position gripping state of the electric looper device is determined by the angle θ between the magnetomotive forces Φr and ΦS at a maximum of 120 to 1
By setting the angle to about 35 degrees (corresponding to the above-mentioned maximum of 60 to 90 degrees), it can be used near the maximum point of generated torque, as shown by the shaded area in FIG. In particular, by setting the actual usage state to around θ-90 degrees, the variation in torque due to the rotation angle becomes such that there is no problem in practical use. Therefore, the generated torque is approximately proportional to the output current of the first Cyrisk power converter 8, and this makes it possible to provide control performance equivalent to that of the conventional DC type eight type.

``As is clear from FIG. 3, changing the direction of the generated torque in an electric manner can be realized by making the thyristors VP and UN conductive.

As is clear from the above explanation, in normal operation, the stator winding 7a consists of two sets (U, U, and U in FIGS. 1 and 3).
■There are 2 sets of 4 thyristors (winding) and thyristors in the inverter section 8C (
In Figures 3 and 5, thyristors UP, VP, UN
, VN) I, is not used, so the pond winding m (w winding) and the thyristor (WP).

WN) can also be omitted.

However, when three sets of windings and six thyristors are combined as in this example, the thyristor range for making two thyristors conductive is 6.
There are different types, and the relationship between the generated torque and the rotation angle of the electric vJ can be made to repeat the same state every 60 degrees in electrical angle, so when actually combining it with a machine, the relative positional relationship with the mating machine. The degree of freedom of choice increases.

According to the first embodiment of the electric looper device of the present invention described above, the following effects can be obtained.

As already mentioned, direct-coupled electric louver devices have a property that the operating rotation angle is extremely small, and in the case of conventional DC motor systems, it is difficult to manufacture ones with large torque because the commutator pieces deform. Hobeta. The electric looper device of the present invention has no commutator or slip ring, and the lead wire of the rotor is directly led out. Therefore, there is no problem of heat generation in the layered ribs and associated thermal deformation, and it is possible to easily manufacture a device with a large torque (a highly reliable electric looper device can be obtained.Especially as mentioned above) When the rotor winding 7b is configured as a field winding that generates the main magnetic flux, as in the embodiment shown in FIG. The wires are relatively small and have a simple structure, making maintenance extremely easy.

The functions and effects of configuration 2 have been described above for the first embodiment (basic configuration) of the present invention, but in practical terms, it is possible to provide an electric looper device with even better performance by adding various functions. becomes possible.

FIG. 5 shows one example of this, that is, a second embodiment of the electric looper device according to the present invention, which is different from FIG.
This includes an armature current correction function generator (first function generator) 8d1 that changes the stator current reference in relation to the rotor rotation angle detection device 10 and its output.

Since the generated torque of the electric looper device having such a configuration changes in relation to the angle θ formed by the center of the magnetomotive force created by the rotor and stator, as shown in equation (1) above, the function generator 8dl is
In order to correct this, a signal is given to the controller 8d of the thyristor power converter 8 to increase or decrease the current flowing through the stator winding 7b in proportion to (1/5en(El)).

As a result, the generated torque remains at a predetermined 1 - regardless of the rotation angle.
This makes it possible to obtain a lot of money. At the same time, in FIG. 5, the rotor winding 7a is
A field current correction function generator (second function generator) 9a for changing the current of b is added.

This is because the electric motor of this device has the same configuration as a rotating field type synchronous electric motor, so the fixed pre-winding I! 117a
and S of the magnetomotive force created by the rotor winding 7b.

Φr interact with each other, producing a so-called armature reaction. This armature reaction is related to the size of the stator winding 7a and the cosine (cosO) of the angle e formed by both magnetomotive forces, and as the current in the stator winding 7b increases, the air gap magnetic flux inside the lightning vJ is increased. Therefore, it is necessary to increase the rotor winding current by an amount commensurate with this decrease, and the function generator 9a performs this.

As described above, in the second embodiment, the rotation angle detection device 10
Since the function generator 8d1 is added to the first embodiment, the torque generated by the motor is accurately proportional to the control signal regardless of the magnitude of the current, and a practical electric looper device can be obtained. .

FIGS. 6(a) and 6(b) show a cable device including a lead wire 7bi for a rotor winding of an electric motor.

Attach the cable reel 7b2.7b2' to the rotating shaft 7f, and connect the terminal lead wire 7b1°7b1 of the rotor winding 171).
After wrapping 17' for more than two times, lengthen the tip to leave enough slack. This can prevent twisting of the lead wires 7bL and 7bl' due to rotation of the rotating shaft 7f. Although Fig. 6 shows an example in which the lead wire is led to the shaft end on the opposite load side of the electric stage, this mechanism is not suitable for electric power! I] It is possible to install it inside the bearing of the machine. Furthermore, the lead wire uses a highly flexible material such as a flat braided conductor.

(Effects of the Invention) According to the present invention, the following effects can be obtained at a pressure h
We can provide one machine power control electric motor control device.

In other words, since there are no electrically conductive parts such as brushes and slip rings in the rotating parts of the motor, there is no possibility of accidents such as thermal deformation due to local heating, sparks caused by poor brush sliding, or broken brushes. This greatly improves reliability, reduces equipment downtime for maintenance, and significantly reduces the number of maintenance personnel.

In addition, since the single machine output limit due to sliding parts is completely eliminated, when the electric motor width direction is large due to large torque or rolling mill stand spacing, the required output l ~ silk can be achieved by increasing the axial dimension. 1q, and there is no practical limit to what can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing a first embodiment of an electric rolling tension control device according to the present invention; 3 and 4 are circuit diagrams and waveform diagrams for explaining the action of FIG. 1,
FIG. 5 shows the rolling mill tension control voltage according to the present invention! Schematic configuration diagram showing the second embodiment of the e-machine device, FIGS. 6(a) and (b)
1 and 5 are plan and front views showing an example of a cable reel device used, and FIGS. 7 and 8 are schematic configuration diagrams of different conventional tension control devices, respectively. 7...Electric motor, 7a...Stator winding, 71)...
Rotor winding, 7C...Stator core slot 1-17d.
...Stator frame, 7e...Rotation center slot, 7f.
... Rotating shaft, 7g, 7Q... Bearing, 7h, 71
1 Bearing bracket, 7N... Center hole for leading wire, 71) 1... Lead wire for rotor winding, 8...
First thyristor power converter, 8a... forward converter,
8b...DC reactor, 8C...Inverse converter, 8d
. . . Control I unit, 9 . . . Second thyristor power conversion device, 10 . . . Rotor rotation angle detection equipment, 3dl . Correction function generator. Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4 (a) Figure 6

Claims (4)

[Claims] (1) A forward converter that receives AC power from a commercial frequency AC power source and converts it into variable voltage DC, an inverse converter that switches the direction of current flowing to the rotor winding of the motor, and control of both of the converters. a second power converter that receives AC power from the commercial frequency AC power supply and converts it into DC power; and a stator that receives power from the first power converter. an electric motor having a winding and a rotor winding supplied with electric power from the second power converter; the output shaft of the electric motor is directly connected to the tension control device of the rolling mill; An electric motor device for tension control in a rolling mill, characterized in that the relative positions of the wire and the rotor winding are such that they can be rotated by an electrical angle of ±90 degrees around a point where the torque generated by the motor is maximum. (2) A forward converter that receives AC power from a commercial frequency AC power source and converts it into variable voltage DC; an inverse converter that switches the direction of the current flowing to the rotor winding of the motor; and control of both of the converters. a second power converter that receives AC power from the commercial frequency AC power supply and converts it into DC power; and a stator that receives power from the first power converter. an electric motor having a winding and a rotor winding supplied with electric power from the second power conversion device; a rotor rotation angle detection device for detecting a rotation angle of a rotor of the motor; a first function generator that calculates a variation in the torque generated by the motor according to a signal from a detection device and corrects a current flowing through the stator winding based on the variation in the torque generated by the motor; and a variation in the torque generated by the motor due to armature reaction. and a second function generator that corrects the current flowing through the rotor winding according to the magnitude of the current flowing through the stator winding, and the output shaft of this motor is directly connected to the tension control device of the rolling mill. The relative positions of the stator winding and rotor winding of the electric motor are such that they can be rotated by an electrical angle of ±90 degrees around a point where the torque generated by the electric motor is maximum. Electric motor device for rolling mill tension control. (3) A combination of a two-pole motor stator winding with a two-phase winding with a 90° phase difference and a four-arm inverter using a thyristor, or a three-phase star connection. An electric motor device for controlling tension in a rolling mill according to claim 1 or 2, which is a combination of a winding and a six-arm thyristor configuration. (4) If the lead wire of the motor rotor winding is guided through a cable reel attached to the rotating shaft, and a slack section is provided between the terminal block of the fixed part from the cable reel, rotation of the shaft is possible. An electric motor device for controlling tension in a rolling mill according to claim 1 or 2, which has a structure that can tighten the lead wire and prevent damage to the lead wire.