JPH05122973A - Motor control method - Google Patents

Abstract

PURPOSE:To raise the speed of carriage in a short time if there is margin in the load of a motor in the and enable production efficiency up by equipping it with a means which automatically operates the revolutions of an objective motor, and decides the constant of a speed detecting circuit. CONSTITUTION:The speed controller 5 of a motor 4 is composed of a speed control circuit 7, a speed detection circuit 8, and a field control circuit 9, and the target speed of carriage is given from the target speedup setter 11 to an operating circuit so as to compute the target revolutions n1 and the speed detection constant k. And, sought target motor revolutions n1 is input into a field current data memory circuit 13 from the operating circuit 12, and the field current If1 at revolutions n1 is selected, and the selected If1 is given to a field control circuit 9, and the field current is controlled to be If1. On the other hand, the sought speed detection constant k is given to a speed detection circuit 8. As a result, the motor is weakened to a field current If1, and the feedback signal VFB also is corrected, and the speed of the motor is increased to the objective revolutions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor control method for a transfer line, and more particularly to an electric motor control method for a transfer line which is composed of a number of devices for sandwiching a material with two rolls and transferring the material from a previous stage to a subsequent stage. Regarding

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of an electric motor controller of a conventional paper machine system. In the figure, the paper 1 is sandwiched between a roll 2 and a roll 3 and conveyed in the direction of the arrow. The roll 2 is driven by an electric motor 4, and the electric motor 4 is speed-controlled by a speed controller 5 which is a known DC Leonard device. The speed control device 5 is composed of a speed control circuit 7, a speed detection circuit 8 and a field control circuit 9, and compares the reference speed v _REF from the speed setter 6 with the speed feedback signal v _{FB of the} electric motor to drive the electric motor 4. It is controlled so as to have a constant speed v. Speed detector 10 directly connected to the electric motor 4
Is inputted to the speed detection circuit 8 and the speed feedback signal v _FB is inputted to the speed control circuit 7. On the other hand, controlled field current I _f is flowed to the field winding of the electric motor 4 at the field control circuit 9.

Then, the speed reference v from the speed setter 6
It is a well-known technique that _REF and the speed feedback signal v _FB from the speed detection circuit 8 are input to the speed control circuit 7 and the deviation thereof controls the electric motor 4 to the speed v set by the speed setter 6. , The explanation is omitted. Also,
At this time, the field current I _f controlled by the field control circuit 9 is naturally constant.

By the way, in the sectional paper machine system, as shown in FIG. 4, a conveying device including a speed control device 5 of an electric motor 4 for driving the same roll 2 as in FIG. 3 is provided for each roll. .. That is, each roll 2a,
A plurality of speed control devices 5a, 5b, ... Of the electric motors 4a, 4b, ... Which drive the respective 2b, ... Are constituted, and the paper 1 is transported at a predetermined transport speed in the arrow direction. Speed reference v from speed setter 6
_REF is derived from this transport speed. Note that 3a and 3b
Is a roll, 6a, 6b ... is a speed setter, 10a, 10b
... is a speed detector.

Here, when the load of all the electric motors has a margin from the initially designed value during the use of this paper machine system, the transport speed (in the case of paper, it is called paper-making speed) is set in order to improve the production efficiency from the customer. ) Is often demanded to be higher than the current design value.

In order to meet such a demand, there are a method of changing the speed reducer on the machine side to increase the conveying speed and a method of increasing the speed of the electric motor for driving each roll to increase the conveying speed.
Usually, the latter method of increasing the speed of the electric motor is used. As a method of increasing the speed of this electric motor, it is obtained from the following equation (1) regarding the speed of the DC motor. n = (V−I _{a Ra} ) / Kφ (1) where n is the motor speed, V is the motor armature voltage, and I _a
Is the motor armature current, R _a is the motor armature resistance, φ is the magnetic flux of the motor field (proportional to the field current _If ), K is a constant From the above equation (1), to control the speed of the motor, increase the motor armature voltage V, there are two or weakening the field current I _f, if there is room in the load of the electric motor, the method usually weaken the latter field current I _f is taken.

[0007]

By the way, the field current I
_The conventional motor speed control method that weakens _f is as follows (1)
(4) It takes steps. (1) Manually calculate the number of rotations of the electric motor that drives each roll from the target (accelerating) conveyance speed. (2) A characteristic pattern of the field current and speed for weakening the field current _If to reduce the rotational speed of each motor obtained in (1) at the rated voltage (each motor has its own). ). (3) _Match the relationship between the speed reference v _REF and the speed feedback signal v _FB to the current rotation speed. (4) Re-adjust each speed control device on site with the values obtained in (2) and (3) above.

By the way, as described above, the sectional paper machine system is provided with a speed controller for each roll, and the number of rolls is about 20 in a normal paper machine system and about 60 in a white board paper machine. It is necessary to design and adjust each of the rolls as described in (1) to (4) above, and there is a disadvantage that both the design time and the on-site adjustment time take a lot of work time.

The present invention has been made in view of the above circumstances, and an object thereof is to increase the speed of the electric motor in a short time when the load of the electric motor in the currently used carrier line has a margin larger than the originally designed value. An object of the present invention is to provide an electric motor control method for increasing the transport speed and increasing the production efficiency.

[0010]

In order to achieve the above object, the present invention is directed to an electric motor of a conveying system which is composed of a plurality of conveying devices which are sandwiched between two rolls and convey material from a front stage to a rear stage. In the control method, the motor for driving the roll and a speed control device for controlling the motor have a means for previously storing a characteristic pattern of a field current and a speed peculiar to the motor, and a target rotation of the motor. Means for automatically calculating the number to determine the constant of the speed detection circuit, and controlling the field current of the electric motor to increase the speed of the electric motor.

[0011]

According to the electric motor control method of the present invention, the field weakening of the electric motor to be driven can be automatically set by giving the conveying speed to be increased to the speed control device for controlling the electric motor which drives each roll. The transport speed can be increased by increasing the speed of the electric motor in a short time.

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. As shown in the figure, the paper 1 is sandwiched between rolls 2 and 3 and conveyed in the direction of the arrow. The roll 2 is driven by an electric motor 4, and the electric motor 4 is speed-controlled by a speed controller 5 which is a known DC Leonard device. The speed control device 5 is composed of a speed control circuit 7, a speed detection circuit 8 and a field control circuit 9, and compares the reference speed v _REF from the speed setter 6 with the speed feedback signal v _{FB of the} electric motor to drive the electric motor 4. It is controlled so as to have a constant speed v. The signal from the speed detector 10 directly connected to the electric motor 4 is input to the speed detection circuit 8, and the speed feedback signal v _FB is input to the speed control circuit 7. On the other hand, the field current I controlled by the field control circuit 9
_f is passed through the field winding of the electric motor 4. The above circuit configuration is the same as the conventional one, and in the present invention, the target machine speed setting device 11,
The arithmetic circuit 12 and the field current data memory circuit 13 are added to the conventional circuit.

Next, the operation of this embodiment will be described.
The target speed-increasing machine speed mpm (conveyance speed) is given to the arithmetic circuit 12 from the target machine-speed setting device 11. As a result, the arithmetic circuit 12 obtains n ₁ and k from the following equations (2) and (3). That is, the target motor rotation speed n ₁ (see FIG. 2) is obtained from the following (2). n ₁ = (mpm · gain ratio) / π · D (2) where mpm is the conveying speed, and the gear ratio is the number of rotations on the input side (motor side) for rotating the output side (roll side) once.
D is the roll diameter. Incidentally, the gear ratio and the roll diameter are preset in the arithmetic circuit by the corresponding gear ratio and roll diameter D of the control device.

The velocity detection constant k is obtained from the following (3). k = n ₀ / n ₁ (3) n ₀ : Rated speed Note that n ₀ is set in advance in the arithmetic circuit as the value of the motor to which the control device corresponds.

The target electric motor speed n ₁ obtained from the above equation (2) is input from the arithmetic circuit 12 to the field current data memory circuit 13. The field current data memory circuit 13 stores the field current and speed characteristic data peculiar to the relevant motor of the control device (data at the rated voltage), and the field at the input rotation speed n _1. The magnetic current I _f1 is selected. (That is, when the field current I _f1 is set, the motor voltage becomes the rated voltage and the motor speed becomes n _1. ) Selected I
_f1 is _supplied to the field control circuit 9, and the field current is controlled to become I _f1 .

On the other hand, the speed detection constant k obtained from the equation (3) is given to the speed detection circuit 8. Assuming that the rotational speed at the initial design stage is n ₀ (rated rotational speed), the speed feedback signal v _FB1 is v _FB1 = (n ₁ / n ₀ ) × v when the target rotational speed n ₁ is increased. _FB0 v _FB0 is the speed feedback signal at the rated speed n ₀ .

Since the speed reference signal v _REF has not been changed at this time, v _FB1 may be multiplied by a constant k in order to obtain a balance. v _FB = v _FB1 × k = (n ₁ / n ₀ ) × v _FB0 × (n ₀ / n ₁ ) = v _{FB0 Due to the} above action, the electric motor is weakened by the field current I _f1 , and the velocity feedback signal v _FB is also reduced. Will be corrected. As a result, the electric motor is speeded up to the target speed.

[0018]

As described above, according to the present invention,
In the case where there is a margin in the load of all electric motors, the field weakening of the electric motors to be driven can be automatically set by giving the conveyance speed to be increased to the speed control device that controls the electric motors that drive each roll. It is possible to provide an electric motor control method for increasing the speed of the electric motor in a short time to increase the conveying speed and improve the production efficiency.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the transport speed and the motor rotation speed in FIG.

FIG. 3 is a configuration diagram of an electric motor control device of a conventional paper machine system.

FIG. 4 is a block diagram of a conventional sectional paper machine.

[Explanation of symbols]

1 ... Paper, 2, 3 ... Roll, 4 ... Electric motor, 5 ... Speed control device, 6 ... Speed setting device, 7 ... Speed control circuit, 8 ... Speed detection circuit, 9 ... Field control circuit, 10 ... Speed detector, 11 ... target machine speed setting device, 12 ... arithmetic circuit, 13 ... field current data memory circuit.

Claims (1)

[Claims] 1. A motor control method for a transport system, comprising: a plurality of transport devices that are sandwiched between two rolls and transport material from a front stage to a rear stage. A motor for driving the roll, and a motor for driving the roll. A speed control device for controlling the electric field current and speed characteristic patterns unique to the electric motor, and means for automatically calculating the target speed of the electric motor to determine the constant of the speed detection circuit. And controlling the field current of the electric motor to enable speedup of the electric motor.