JPS5854595B2 - Control device for commutatorless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a commutatorless motor that performs constant output operation.

Generally, the tension of unwinding machines and winding machines for rolling mills, paper machines, etc. is controlled because the coil diameter changes over time.

The electric motor that drives the unwinding machine or the winding machine is controlled at a constant output.

Constant output control of a DC motor is performed by controlling the armature current and back electromotive force to a constant value.

Constant control of the back electromotive force changes the field current according to the motor rotation speed.

In the case of a DC motor, the coil diameter is a function only of the field current, regardless of the line speed (rolling speed in the case of a rolling mill) of the material to be drawn.

In the case of a non-commutator motor, in order to improve the power factor of the motor and to prevent the withstand voltage of the thyristor that constitutes the frequency converter from becoming higher than necessary, when performing back electromotive force control, the motor side point of the frequency converter is It is desirable to use both arc angle (control advance angle) control and field current control.

However, when controlled in this way, the coil diameter becomes a function of the control advance angle and the field current, and cannot be calculated from the field current alone.

Furthermore, the control advance angle varies greatly depending on the motor speed.

Incidentally, the coil diameter of the unwinding machine and winding machine of a rolling mill, paper machine, etc. changes with time, and the moment of inertia thereof also changes with time.

Therefore, during acceleration/deceleration, an acceleration/deceleration current commensurate with the moment of inertia and the acceleration/deceleration time is required.

Therefore, in order to stably perform constant output control during acceleration/deceleration, it is necessary to apply acceleration/deceleration current in addition to the tension setting current.

A circuit that generates acceleration/deceleration current commands based on the moment of inertia and acceleration/deceleration time is called a forcing control circuit.

FIG. 1 shows a constant output control device for a DC motor having a forcing control circuit.

Figure 1 shows the tension setting device 11. Current control circuit 12, current detector 13, current transformer 14, DC variable power supply 15, DC motor 16, back electromotive force control circuit 17, field current control circuit 18
, a DC variable power supply 19, a shunt 20, and a forcing control circuit 25.

The shunt 20 is connected to the field coil 16F of the DC motor 16.

The forcing control circuit 25 includes a function generator 21 and a multiplier 2.
2 and a differentiator 23.

In the above configuration, power is supplied to the DC variable power supply device 15 from the AC power supply AC8, and this supplied current is detected by the current detector 13.

A detection output 13A of the current detector 13 is input to the current control circuit 12.

The current control circuit 12 has a current command output 1 of the tension setting device 11.
1A is input.

Therefore, the current control circuit 12 calculates by comparing the detection output 13A and the current command output 11A, and the output 12A is inputted to the DC variable power supply 15 to perform, for example, phase control.

The output 15A of this DC variable power supply device 15 is
6 armature current is controlled.

Next, control to keep the back electromotive force of the electric motor 16 constant will be explained.

The back electromotive force control circuit 17 receives a back electromotive force command signal 17V corresponding to the actual line speed value 1 and a back electromotive force detection signal 16A of the DC motor 16.

The back electromotive force control circuit 17 calculates by comparing the two human forces of 17V and 16A, and the output 17A is inputted to the field current control circuit 18 as a field current command.

A detection signal output 20A from the shunt 20 is input to the field current control circuit 18.

The field current control circuit 18 compares and calculates both human forces, and controls the DC variable power supply device 19 with its output 18A.

Field coil 16F with output 19A of DC variable power supply 19
control the field current of

As a result, the back electromotive force of the motor becomes constant regardless of the rotation speed.

Note that the DC variable power supply device 19 is supplied with AC power supply FAC8.

Next, details of the forcing control circuit 25 will be explained.

In the case of a DC motor, the coil diameter can be expressed as a function of the field current If.

The function generator 21 outputs a moment of inertia (GD2) corresponding to the detected field current 20A.

The output 21A of the function generator 21 is input to the multiplier 22.

A differential output 23A from a differentiator 23 is input to the multiplier 22.

The line speed command value 8 (23V) and the line speed actual value V (17V) are input to the differentiator 23.

The differentiator 23 generates an output 23A which is the sum of the differential values obtained by differentiating the signals V, , V, respectively.

The differentiator 23 includes an input resistor for the signals V, , V, two capacitors for differentiation, an operational amplifier for adding the differential values, and the like.

The reason why both the command value (8) and the actual value (2) are used is to improve the followability at the start and end points of acceleration and deceleration.

The command value ■8 changes in a ramp-like manner, but there is a delay in the actual value ■ due to a delay in the control system.

Therefore, the followability can be improved at the start point of acceleration/deceleration by changing the command value 8, and by changing the actual value 8 at the end point.

The differentiator 23 is for detecting the rate of change (acceleration/deceleration) of the line speed, and the rate of change may be detected by inputting only either the line speed command value (8) or the actual value (2).

However, it is preferable to use both signals ■8°■ because the followability improves as described above.

When inputting both the command value ■8 and the actual value ■ to the differentiator 23, the ratio of both signals is set to l/2°1/3 and 2/3 or 1.
/4 and 3/4 so that the total is 1 (■R or ■).

The ratio of both signals V, , V is set by the input resistance within the differentiator 23.

Further, the ratio between the two signals V, , V is determined by the characteristics of the rewinding machine or winding machine driven by the electric motor 16.

The differentiator 23 determines the acceleration/deceleration time according to the rate of change of the command value (8).

Multiplier 22 multiplies inputs 21A and 23A and outputs 22A.
is applied to the current control circuit 12.

The output 22A is the product of the moment of inertia and the acceleration/deceleration, and becomes the acceleration/deceleration torque command value.

The acceleration/deceleration torque command value 22A has a substantially rectangular wave shape.

As described above, the acceleration/deceleration torque command value required during acceleration/deceleration is generated independently of the tension command, thereby enabling stable constant tension operation even during acceleration/deceleration.

However, this type of forcing control circuit cannot be applied when using a non-commutator motor due to the control advance angle.

The present invention has been made in view of the above points, and an object of the present invention is to provide a control device for a commutatorless motor that can perform stable constant output control regardless of the coil diameter and the magnitude of acceleration/deceleration time.

The present invention is to obtain the coil diameter in consideration of the firing angle of the frequency converter on the motor side, and to determine an appropriate amount of forcing.

Hereinafter, the present invention will be explained in detail based on the embodiment shown in FIG.

The embodiment shown in FIG. 2 includes a tension setting device 31 and a current control circuit 32.
, gate control circuit 33, current transformer 34, current detector 35,
A variable frequency power supply device 36 consisting of a frequency converter, a synchronous motor 37, a distributor 38, a back electromotive force control circuit 39, a back electromotive force detector 40, a terminal voltage detector 41. Terminal voltage setting device 42
, a terminal voltage control circuit 43, a field current control circuit 44, a shunt 45, a DC variable power supply 46, and a forcing control circuit 47.

A field coil 37F is connected to the shunt 45.

AC power supplies AC8 and FAC8 are supplied to the variable frequency power supply device 36 and the DC variable power supply device 46, respectively.

In the above configuration, the output 31A of the tension setting device 310 is inputted to the current control circuit 32 as a current command value (constant value).

The current transformer 34 and the current detector 35 detect the current flowing from the power source AC8, and the output 35A thereof is input to the current control circuit 32.

The current control circuit 32 compares and calculates each input, and its output 32A is input to the gate control circuit 33.

The output 33A of the gate circuit 33 controls the output 36A of the variable frequency power supply 36.

The armature current of the synchronous motor 37 is controlled to be constant by the output 36A of the variable frequency power supply 36.

The gate control circuit 33 receives the output signal 38A of the distributor 38 and the control advance angle control signal 39 from the back electromotive force control circuit 39.
A is input.

The gate control circuit 33 controls the firing angle on the motor side of the frequency converter constituting the variable frequency power supply device 36 by each input, and achieves constant output control by controlling the back electromotive force of the motor 37 to be constant.

The back electromotive force detector 40 detects the back electromotive force and its output 40
A is input to the back electromotive force control circuit 39.

Back electromotive force! 11M] A calculation is made by comparing the human power 40A of the circuit 39 with the back electromotive force command 39V corresponding to the actual line speed value (2), and this output 39A is applied to the gate control circuit 33 as a control advance angle control signal.

The terminal voltage detector 41 detects the terminal voltage and its output 41
A is input to the terminal voltage control circuit 43.

A terminal voltage command 42A from the terminal voltage setter 42 is input to the terminal voltage control circuit 43.

The terminal voltage control circuit 43 calculates by comparing both human forces, and the output 43A is sent to the field current control circuit 44 as a field current command.
is input.

The output 44 of the field current control circuit 44 is similar to the circuit shown in FIG.
A controls the field current of the field coil 37F.

As a result, the terminal voltage of the electric motor 37 is controlled to be constant.

Constant back electromotive force control of the commutatorless motor is performed by controlling the control advance angle γ and the field current If.

That is, the following equation holds between the run speed (■) and the motor back electromotive force EM during constant output control.

Furthermore, there is a relationship between the line speed (■) and the coil diameter as shown in the following equation.

The motor speed N in equation (2) is N260ω/2π, and (
If we rearrange the equation 2), we get equation (3).

As is clear from equation (3), the coil diameter is ζφ and co
It can be expressed as a multiplication value of sγ.

That is, the coil diameter can be calculated by dividing the rolling speed (2) by the motor rotation speed.

Therefore, if the diameter of the coil at line speed ■ can be calculated, the moment of inertia (GD2) at that time can be calculated using the following equation.

However, K is a constant, and D is the minimum coil diameter and a constant.

Using the moment of inertia GD2 obtained by equation (4), the acceleration/deceleration torque Tad during acceleration/deceleration is calculated by the following equation, which is known as a basic equation for the motor system.

tad: acceleration/deceleration time JN: change in rotational speed due to acceleration/deceleration FIG. 3 shows a specific configuration of the forcing control circuit 47.

The illustrated circuit includes function generators 48, 49, multipliers 50, 51
．． It is composed of a differentiator 52.

The function generator 48 outputs a cos 7' signal 48A according to the input of the counter electromotive force control circuit 390 and the advanced Tsunoda force 39A.
This output 48A is input to a multiplier 50.

On the other hand, the detected field current signal 44F from the shunt 45 is input to the multiplier 50, and the multiplier 50 calculates the coil radius signal output 50A by multiplying the power of both people, and the output 50A is sent to the function generator 49. is input.

The function generator 49 inputs the coil radius detection signal 50A and outputs a signal 51 proportional to the moment of inertia GD2 as shown in FIG. 4 according to the relationship of equation (4).

The differentiator 52 receives the line speed command value vR and the actual line speed value in the same manner as the differentiator 23 in FIG. 1, and outputs a signal 52A proportional to the acceleration/deceleration.

Moment of inertia detection signal 51A and acceleration/deceleration detection signal 52
A is multiplied by a multiplier 51.

The multiplier 51 outputs a forcing signal JIf proportional to the acceleration/deceleration torque Tad in equation (4) as its output 51B.

In this way, the forcing amount lIF is determined, and the coil diameter is determined by taking into consideration the firing angle (control advance angle) on the motor side of the variable frequency power supply device 36.

For this reason, during acceleration/deceleration, especially during acceleration, the variable frequency power supply 3
As explained above, according to the present invention, it is possible to prevent commutation failure of the thyristor constituting the thyristor 6 and to perform stable tension control. Can be done.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a constant output control circuit of a forcing control circuit using a DC motor, and Fig. 2 is a circuit diagram of a control circuit with a forcing control circuit of the present invention using a non-commutator motor.
FIG. 3 is a circuit diagram of an example of the forcing control circuit, and FIG. 4 is a characteristic diagram of the function generator shown in FIG. 32...Current control circuit, 39...Back electromotive force control circuit, 47...7 ossing control circuit.

Claims (1)

[Claims] 1. A variable power supply device consisting of a frequency converter that converts the frequency of alternating current, and an armature current supplied from the variable power supply device to drive a winder or unwinder for the stretched material to be stretched. a synchronous motor, a current control circuit that controls a power supply side firing angle of the frequency converter so that the armature current of the synchronous motor becomes a current command value, and a field control circuit that controls a field current of the synchronous motor. , a back electromotive force control circuit that controls a firing angle on the motor side of the frequency converter, and a back electromotive force control circuit that controls the field current and the firing angle on the motor side to keep the back electromotive force of the synchronous motor constant. In a control device for a commutator motor, a coil diameter calculating means for calculating a coil diameter of the winding machine or unwinding machine obtained by multiplying the field current by the cosine value of the firing angle on the motor side; a moment calculation means for calculating the moment of inertia from the coil, diameter and gravitational acceleration determined by the calculation means; and a differential calculation means for differentiating the line speed signal of the stretched material and outputting a signal proportional to the acceleration/deceleration of the line speed. and a forcing control circuit that multiplies the moment of inertia by the output of the differential calculation means and outputs an acceleration/deceleration torque command value, and adds the acceleration/deceleration torque command value to the current command value. A control device for a commutatorless motor, characterized in that the control device is added to the current control circuit.