TWI844021B - Electric motor speed control device - Google Patents

Abstract

According an embodiment provides an electric motor speed control device, which having a first computing means for supplying a first speed reference to a first variable speed control device for speed-controlling a first electric motor for driving a table roll of a first conveying table; and a second computing means for supplying a second speed reference to a second variable speed control device for speed-controlling a second electric motor for driving a table roll of a second conveying table provided downstream of the first conveying table, the second computing means calculates a conveying speed of a rolled material to be conveyed as a target conveying speed, and a fastest acceleration/deceleration time based on an actual speed data of the second electric motor, the target conveying speed and preset electric motor parameters, generates a speed reference pattern based on the actual speed data, the target conveying speed and the fastest acceleration/deceleration time, and supplies to the second variable speed control device as the second speed reference.

Description

Motor speed control device

The present invention relates to a speed control device for an electric motor.

In the rolling process of metal materials such as steel, the rolled material is transported on a conveying table. The conveying tables that transport the rolled material on the conveying rollers are mostly set up in a plurality of continuous manner on the rolling equipment. The plurality of conveying tables mentioned above are each composed of a plurality of conveying rollers. The plurality of conveying rollers are driven by an independent motor according to each conveying table.

When the conveyed rolled material is transferred between the conveyor tables of conveyor rollers driven by different motors, if there is a speed difference between the motors of the conveyor rollers before and after the transfer, the rolled material will slip on the conveyor rollers and the conveying surface of the rolled material may be damaged by slippage.

Therefore, there is a known technology that uses two position detectors on the conveying table on the upstream side to calculate the conveying speed of the rolled material and corrects the speed of the motor on the downstream side so that it matches the calculated conveying speed (for example, Patent Document 1).

According to the above technology, since the speed of the motor of the downstream conveying table is matched with the conveying speed of the rolled material conveyed from the upstream, the slippage of the rolled material when it moves on the conveying table can be suppressed, and the slippage damage of the conveying surface can be prevented from occurring.

In contrast, the technology of Patent Document 1 does not take into account the operation of the downstream motor during the acceleration and deceleration period of the speed reference change. Therefore, there is a problem that the speed correction of the downstream motor will be too late before the rolled material moves to the conveyor table. In order to avoid the above problem, the speed reference correction must be fully started upstream before the rolled material reaches the downstream conveyor table. However, due to the conveying speed of the rolled material or the length of the conveyor table, etc., there may be a situation where the speed reference correction cannot be fully performed.

[Prior Art Literature]

[Patent Literature]

Patent document 1: Japanese Patent Publication No. 60-111712

The embodiment of the present invention is an invention completed to solve the above-mentioned problem, and its purpose is to provide a speed control device for an electric motor, which is not easy to cause the slip of the rolled material when the conveying table is transferred.

The motor speed control device of the embodiment of the present invention comprises: a first operation means for supplying a first speed reference to a first variable speed control device, and the first variable speed control device controls the speed of a first motor driving a table roller of a first conveying table; a second operation means for supplying a second speed reference to a second variable speed control device, and the second variable speed control device controls the speed of a second motor driving a table roller of a second conveying table, and the second conveying table is arranged downstream of the first conveying table, and the second variable speed control device controls the speed of a second motor driving a table roller of a second conveying table. The second calculation means calculates the conveying speed of the rolled material conveyed by the first conveying table as the target conveying speed converted into the speed of the second motor, and calculates the fastest acceleration and deceleration time according to the speed performance data of the second motor, the target conveying speed, and the motor parameters related to the second motor that are preset, and generates a speed reference pattern according to the speed performance data, the target conveying speed, and the fastest acceleration and deceleration time as the second speed reference to be supplied to the second variable speed control device.

According to the implementation form of the present invention, a speed control device for the motor can be realized which is not likely to cause the rolled material to slip when the conveying table moves.

1: Pressed and rolled materials

2a to 2e: Table roller

3a,3b: Electric motor

4a,4b: Variable speed control device

5a,5b: Position detector

10: Speed control device

14: Target transport speed calculation function

15: Calculation function for the arrival time of rolled materials

16: Motor parameter setting function

17: Acceleration and deceleration rate calculation function

18: Speed-based calculation function

19a,19b: Speed benchmark setting function

20a,20b: Operational unit

21: Upstream motor speed correction function

100,102:Transport table

210: Speed control device

217: Acceleration and deceleration rate calculation function

220a, 220b: Operational unit

222: Power consumption calculation function

Da, Db: Position detection signal

J, J ₁ , J ₂ : Power consumption

N: Speed standard

N ₁ : Speed performance

N ₂ : Target transport speed

N _C : Correction value

N(t): Mode

N _U :Speed Performance

t ₀ : Fastest acceleration/deceleration time

t ₁ : Acceleration and deceleration time

t ₃ : Arrive at scheduled time

GD ² : Inertial moment

T _A : Rated torque

α,α ₁ : acceleration/deceleration rate

τ,τ ₀ ,τ ₁ ,τ ₂ ,τ ₁₁ : time

I ₁ ² : The value of the second power of the primary current of the motor

FIG1 is a schematic block diagram of a speed control device for a motor according to embodiment 1.

FIG. 2 is a schematic curve diagram for explaining the operation of the speed control device of embodiment 1, and is an example of a curve diagram showing the time variation of the speed reference.

FIG3 is a schematic block diagram of a speed control device for a motor according to Embodiment 2.

FIG. 4 is a schematic curve diagram for explaining the operation of the speed control device of the second embodiment, and is an example of a curve diagram showing the time variation of the speed reference.

The following describes various implementation forms of the present invention with reference to the drawings.

In addition, the diagrams are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as the actual object. Furthermore, even when the same part is shown, there may be cases where the size or ratio is different depending on the diagram.

In addition, in the specification and each figure of this application, the same symbols are attached to the same elements in the figures that have been shown and the figures that have been explained, and the detailed description is appropriately omitted.

(Implementation Type 1)

FIG1 is a schematic block diagram illustrating a speed control device of a motor according to the present embodiment.

In FIG. 1 , in addition to the speed control device 10 of the present embodiment, the conveying tables 100 and 102 for conveying the rolled material 1 under the speed control of the speed control device 10 are also shown. The conveying tables 100 and 102 are arranged in an adjacent manner, and the conveying table (first conveying table) 100 is arranged upstream of the conveying table (second conveying table) 102. The rolled material 1 is conveyed from the upstream conveying table 100 to the downstream conveying table 102.

The conveying table 100 is arranged in such a manner that the table rolls 2a to 2c driven by the motor (first motor) 3a convey the rolled material 1 from upstream to downstream. The rolled material 1 is conveyed from upstream to downstream as the table rolls 2a to 2c rotate. The motor 3a is driven by the variable speed control device (first variable speed control device) 4a.

The conveying table 102 is provided in such a manner that the table rollers 2d and 2e driven by the motor (second motor) 3b convey the rolled material 1 from upstream to downstream. The rolled material 1 conveyed from the upstream conveying table 100 is conveyed further downstream as the table rollers 2d and 2e rotate. The motor 3b is driven by the variable speed control device (second variable speed control device) 4b.

The motors 3a and 3b are AC motors, such as induction motors. The variable speed control devices 4a and 4b control the speed of the motors 3a and 3b according to their respective speed standards.

The speed control device 10 collects speed data of the motors 3a and 3b. As shown in this example, when the speed of the motors 3a and 3b is controlled by sensorless vector control, as shown by the solid line, the speed control device 10 collects the speed performance of the motors 3a and 3b from the variable speed control devices 4a and 4b. When the speed of the motors 3a and 3b is controlled by sensorless vector control, the speed control device 10 receives the speed data of the motor from the speed detector provided in the motor as shown by the dotted line.

The conveyor table 100 is provided with position detectors 5a and 5b for the rolled material 1. The position detector 5a is provided upstream of the position detector 5b. The position detectors 5a and 5b detect the front end of the rolled material 1 and respectively output active position detection signals Da and Db until the material passes the rear end. The position detectors 5a and 5b are sensors of appropriate type depending on factors such as the installation environment of the conveyor table. In the case of hot rolling, a hot metal detector can be used. As described in detail later, the position detectors 5a and 5b measure the time from when the upstream position detector 5a detects the front end of the rolled material 1 until the downstream position detector 5b detects the front end of the rolled material 1, so as to calculate the conveying speed of the rolled material 1 between the position detectors 5a and 5b.

The number of position detectors installed is not limited to two, and can be three or more. The conveying speed of the rolled material can be calculated based on the number and location of the position detectors installed.

In this example, although no position detector is shown on the downstream conveyor table 102, a position detector is installed at an appropriate location to meet the needs of tracking the rolled material.

For ease of understanding, the following description is based on the case of two-stage conveyor tables 100 and 102, but the conveyor table is not limited to two stages, and can also be three stages or more. Motors 3a and 3b can drive any number of table rollers, but in Figure 1, it is assumed that motor 3a drives three table rollers and motor 3b drives two table rollers.

In the case where the conveying table is to be set further downstream than the conveying table 102, the conveying speed of the rolled material on the conveying table 102 can be calculated by using a position detector set on the conveying table 102.

The motor speed control device 10 is connected to the position detectors 5a and 5b. The speed control device 10 calculates the target conveying speed _N2 of the rolled material 1 between the position detectors 5a and 5b based on the position detection signals Da and Db outputted by the position detectors 5a and 5b and the distances between the position detectors 5a and 5b.

In the speed control device 10, the speed performance data of the upstream motor 3a is used to correct the speed of the upstream motor 3a relative to the speed standard of the downstream motor 3b. The speed performance data of the downstream motor 3b is used to calculate the acceleration and deceleration rate. In addition, although not shown, the speed performance data is also used for feedback of the variable speed control devices 4a and 4b.

The speed control device 10 is connected to the variable speed control devices 4a and 4b. The speed control device 10 calculates an appropriate speed reference for each of the variable speed control devices 4a and 4b, and supplies the calculated speed reference to the variable speed control devices 4a and 4b.

More specifically, the speed control device 10 calculates the expected arrival time t ₃ for the rolled material 1 to reach the downstream conveyor table 102 using the calculated conveying speed and the distance to the downstream conveyor table 102. The speed control device 10 calculates the fastest acceleration/deceleration time t ₀ of the downstream motor 3 b using the conveying speed, motor specifications, and mechanical elements, and calculates the acceleration/deceleration rate α based on the calculated fastest acceleration/deceleration time t _0. The speed control device 10 generates a speed reference pattern N(t) for the downstream motor 3 b using the calculated acceleration/deceleration rate α and supplies it to the variable speed control device 4 b. The speed reference pattern is data indicating the temporal variation of the speed reference, and is data that presents, for example, the speed reference at each moment in a time series.

The speed control device 10 preferably corrects the speed reference of the upstream motor 3a when the fastest acceleration/deceleration time _t0 is compared with the scheduled arrival time _t3 and the scheduled arrival time _t3 is shorter than the fastest acceleration/deceleration time _t0 .

As described above, the speed control device 10 of this embodiment is controlled so that the speeds of the motors 3a, 3b of the adjacent conveyor tables 100, 102 are approximately the same speed within the arrival time of the rolled material.

The configuration example of the motor speed control device 10 is described in more detail.

The speed control device 10 has calculation units 20a and 20b. The speed control device 10 preferably further has an upstream motor speed correction function 21 and speed reference setting functions 19a and 19b.

The calculation unit (first calculation unit) 20a generates and outputs a speed reference pattern of the motor 3a on the upstream side, and the calculation unit (second calculation unit) 20b generates and outputs a speed reference pattern of the motor 3b on the downstream side. The calculation units 20a and 20b have roughly the same structure, and the calculation unit 20b on the downstream side is described below. In addition, when the calculation unit 20a is provided for the motor located at the most upstream, it is not necessarily necessary to have the same structure as the calculation unit 20b. For example, a speed reference pattern calculated according to conditions set by a host computer (not shown) may be pre-set.

The calculation unit 20b includes a target conveying speed calculation function 14, a predetermined time for the rolled material to arrive at the rolled material calculation function 15, a motor parameter setting function 16, an acceleration/deceleration rate calculation function 17, and a speed reference calculation function 18.

The target transport speed calculation function 14 receives the position detection signals Da and Db as input. The position detection signals Da and Db are output from the position detectors 5a and 5b, respectively. The target transport speed calculation function 14 calculates the transport speed of the rolled material 1 transported by the upstream transport table 100 using the position detection signals Da and Db and the data of the distance between the positions at which the position detectors 5a and 5b are respectively set, and outputs it as the target transport speed _N2 . The target transport speed _N2 is converted into the rotation speed of the motor and output.

The calculation function 15 for the arrival of the predetermined time of the rolled material is pre-set with data of the distance between the positions where the conveying tables 100 and 102 are respectively set. The distance between the positions where the conveying tables 100 and 102 are respectively set is set as, for example, the distance between the position detector 5b on the downstream side of the two position detectors 5a and 5b and the position where the table roller 2d on the most upstream side of the conveying table 102 is set. It is also possible to set the position of the conveying table 102 slightly upstream of the table roller 2d in consideration of the measurement error or calculation error of the distance or speed.

The expected arrival time calculation function 15 receives the target conveying speed _N2 calculated by the target conveying speed calculation function 14. The expected arrival time calculation function 15 calculates the expected arrival time _t3 of the rolled material 1 at the conveying table 102 according to the target conveying speed _N2 and the distance between the conveying tables 100 and 102, and outputs it.

The motor parameter setting function 16 extracts the motor parameters required for calculation from a parameter storage unit (not shown) and outputs them. The parameter storage unit may be provided in a memory device connected to the outside, or in the memory unit of the speed control device 10. The motor parameters include the specifications of the motor and various metadata of the machine driven by the motor. The motor specifications include overload capacity k, rated torque _TA [kgf‧cm], etc. The various metadata of the machine include the inertial torque ^GD2 [ ^kgf‧cm2 ] of the mechanical system such as the roller or reduction gear, etc. The inertial torque GD ² data can be set for the motor and the mechanical system separately, or it can be set as the total inertial torque value of each motor.

The acceleration/deceleration rate calculation function 17 inputs the target transport speed N ₂ , the speed performance N ₁ of the downstream motor 3 b and the necessary parameters of the motor, and calculates the acceleration/deceleration rate α based on these parameters. The value calculated by the target transport speed calculation function 14 is used as the target transport speed N ₂ . The speed performance N ₁ is the speed performance of the motor 3 b. The motor parameters are set and output by the motor parameter setting function 16. In this example, the motor parameters are the overload capacity k of the motor 3 b, the rated torque _TA [kgf‧cm], the torque _Tm [kgf‧cm] equivalent to the mechanical system loss, and the inertial torque GD ² [kgf‧cm ² ]. The inertial torque ^GD2 is the sum of the motor side and the mechanical side.

The acceleration/deceleration rate α is calculated as follows.

α = (N ₂ -N ₁ ) / t ₀

Here, the fastest acceleration/deceleration time _t0 is obtained by the following formula (1) using the target transport speed _N2 , the speed performance _N1 of the motor 3b and the parameters of the motor. In addition, in this embodiment and other embodiments described below, when the motor 3b is accelerating/decelerating, it is operated at a certain torque, and the fastest acceleration/deceleration time _t0 is set to be >0. In addition, formula (1) represents acceleration, and in deceleration, the denominator in the integral symbol is set to ( _kTA + _Tm ).

The speed reference calculation function 18 inputs the target conveying speed _N2 , the actual speed performance _N1 of the motor 3b, the expected arrival time t3 of the rolled material ₁ , the fastest acceleration/deceleration time _t0 and the acceleration/deceleration rate α to generate a speed reference pattern N(t). The speed reference calculation function 18 supplies the generated pattern N(t) to the variable speed control device 4b.

The upstream motor speed correction function (upstream motor speed correction means) 21 is input with the scheduled arrival time _t3 and the fastest acceleration/deceleration time _t0 . The upstream motor speed correction function 21 compares the scheduled arrival time _t3 with the fastest acceleration/deceleration time _t0 . When _t3 < _t0 , the correction value _NC of the speed reference is output, and the speed reference for the upstream motor 3a is corrected in such a way that _t3 ≧ _t0 .

In this example, the upstream motor speed correction function 21 is used to input the speed performance N _U of the motor 3a on the upstream side. A correction value for t ₃ <t ₀ is pre-set in the upstream motor speed correction function 21. This correction value N _C is set to, for example, a value corresponding to the speed performance N _U on the upstream side, and the larger the absolute value of the speed performance N _U is, the larger the correction value is set. For example, a table is pre-set in the upstream motor speed correction function 21, which divides the motor 3a into a plurality of speed ranges and sets the correction values corresponding to the divided speed ranges. In addition, the correction value set in the upstream motor speed correction function 21 may be a constant value independent of the speed performance N _U of the motor 3a.

The speed reference setting functions 19a and 19b receive the speed reference pattern from the calculation units 20a and 20b, and convert the data of the speed reference pattern into an appropriate format and supply it to the variable speed control devices 4a and 4b. The speed reference setting functions 19a and 19b have a calculation function for the input data and instructions. Although not shown, the speed reference setting functions 19a and 19b output the speed reference pattern when an operation instruction is input and the operation instruction becomes active. In this example, when the upstream motor speed correction function 21 outputs the correction value _NC of the speed reference, the upstream speed reference setting function 19a applies the correction value _NC to the current speed reference pattern. For example, the speed reference setting function 19a calculates a new speed reference based on the speed reference output by the calculation unit 20a and the correction value _NC output by the upstream motor speed correction function 21, and outputs the new speed reference.

The operation of the speed control device 10 of this embodiment is described.

FIG. 2 is a schematic curve diagram for explaining the operation of the speed control device of this embodiment, and is an example of a curve diagram showing the time variation of the speed reference.

FIG2 shows a curve diagram of the time variation of the speed reference pattern N(t) generated by the speed reference calculation function 18 and output by the speed reference setting function 19b. The vertical axis is the speed reference N and the horizontal axis is the time τ. FIG2 shows an example of the motor 3b accelerating from a low speed to a high speed.

As shown in FIG. 2 , the speed reference pattern N(t) generated by the speed reference calculation function 18 includes data according to the size of the speed reference N at each moment. At moment τ ₀ , the speed reference N is set to the speed performance N ₁ of the motor 3b. The moment τ ₀ is the moment when the extruded material 1 passes the starting point of the distance between the respective setting positions of the conveying tables 100 and 102, for example, the moment when the extruded material 1 passes the position where the position detector 5b is set. During the fastest acceleration/deceleration time t ₀ between moment τ ₀ and moment τ ₁ , the pattern N(t) rises linearly at the slope of the acceleration/deceleration rate α. At moment τ ₁ , the pattern N(t) reaches the target conveying speed N ₂ . Thereafter, from time τ ₁ to time τ ₂ , the mode N(t) is shifted at a certain target conveying speed N _2. Time τ ₂ is the time when the rolled material 1 reaches the end of the distance between the positions where the conveying tables 100 and 102 are respectively set, for example, at the downstream conveying table 102, the front end of the rolled material reaches the position where the table roller 2d on the upstream side is set. That is, the period from time τ ₀ to time τ ₂ is the expected arrival time t ₃ of the rolled material 1.

The upstream motor speed correction function 21 inputs the calculated values of the fastest acceleration/deceleration time _t0 and the arrival time _t3 from the speed reference calculation function 18. The upstream motor speed correction function 21 compares the fastest acceleration/deceleration time _t0 and the arrival time _t3 . In this example, since the arrival time _t3 is longer than the fastest acceleration/deceleration time _t0 , the upstream motor speed correction function 21 does not output the correction value N _C , and the calculation unit 20a supplies the speed reference set at the time to the variable speed control device 4a via the speed reference setting function 19a.

When the predetermined time _t3 is shorter than the fastest acceleration/deceleration time _t0 , the upstream motor speed correction function 21 outputs the correction value _NC of the speed standard to the speed standard setting function 19a. In this example, since it indicates that the motor 3b is accelerating, when _t3 < _t0 , the upstream motor speed correction function 21 outputs the correction value _NC in such a manner as to reduce the target conveying speed _N2 as shown by the downward arrow in FIG. 2. The correction value _NC at this time is, for example, data having a negative value, and is added to the speed standard output by the calculation unit 20a by the speed standard setting function 19a. In this way, the variable speed control device 4a is input with a speed standard having a smaller value than the original value, so as to reduce the conveying speed of the rolled material 1.

The above description is for the case where the downstream motor 3b is accelerated. However, when the motor 3a is decelerated, the upstream motor 3a is also corrected to adjust the conveying speed of the rolled material 1. When the motor 3b is decelerated and _t3 < _t0 , the upstream motor speed correction function 21 outputs a correction value _NC having a positive value, and the upstream speed reference setting function 19a adds the correction value having a positive value to the speed reference output by the calculation unit 20a, and outputs a new speed reference.

As described above, the upstream motor speed correction function 21 is preset with a correction value _NC . When _t3 < _t0 , a positive or negative correction value _NC is outputted according to whether the downstream motor 3b is accelerating or decelerating. The magnitude of the correction value _NC may be a value set according to the speed performance _NU of the upstream motor 3a, or may be a constant value. In the above example, since two position detectors 5a and 5b are provided, the calculation of the target conveying speed _N2 is performed once, and the comparison and determination of the fastest acceleration/deceleration time _t0 and the arrival time _t3 are also performed once. Without being limited to the above method, the comparison and determination of the fastest acceleration/deceleration time _t0 and the arrival time _t3 may be performed multiple times according to the number of position detectors to output the correction value _NC .

The effect of the motor speed control device 10 of this embodiment is described.

The speed control device 10 of this embodiment has a calculation unit 20b, in which the speed of the downstream motor 3b can be adjusted to calculate the acceleration/deceleration rate α in a manner that includes the specifications of the motor 3b and mechanical elements. Therefore, it is not necessary to start the acceleration/deceleration operation of the downstream motor 3b from a state where the die-cutting material is located quite far away, which can not only reduce the slip damage of the die-cutting material, but also enable a smoother die-cutting step.

The speed control device 10 of this embodiment can further include an upstream motor speed correction function 21. When the calculation unit 20b calculates the fastest acceleration/deceleration rate α, the measured conveying speed of the die-rolled material 1 can be used as the target conveying speed N ₂ , and the expected arrival time t ₃ of the die-rolled material 1 can be calculated based on the target conveying speed N ₂ and the distance between the conveying tables 100 and 102. The upstream motor speed correction function 21 compares the fastest acceleration/deceleration time t ₀ obtained based on the acceleration/deceleration rate α with the expected arrival time t ₃ obtained based on the conveying speed of the die-rolled material 1 to determine whether appropriate speed adjustment is performed. The upstream motor speed correction function 21 corrects the speed of the upstream motor 3a when it is determined that the acceleration/deceleration operation of the downstream motor 3b is insufficient to adjust the speeds of the motors 3a and 3b. Therefore, even if the fastest acceleration/deceleration rate α is determined based on the mechanical factors of the downstream motor 3b, the speeds of the motors 3a and 3b can be appropriately adjusted by correcting the speed of the upstream motor 3a.

The above specific example is to calculate the conveying speed of the rolled material 1 based on the position detection signals Da and Db output by the position detectors 5a and 5b and the distance between the position detectors 5a and 5b. This method is a preferred method because the direct conveying speed of the rolled material 1 can be used as the target conveying speed _N2 . Instead of performing the calculation based on the position detection signals Da and Db and the distance between the position detectors 5a and 5b, the speed performance N _U of the upstream motor 3a can be used as the conveying speed of the rolled material 1.

(Implementation Type 2)

FIG3 is a schematic block diagram illustrating the speed control device of the motor of this embodiment.

The speed control device 210 of this embodiment adjusts the acceleration/deceleration rate of the motor 3b on the downstream side to minimize the power consumption J of the motor 3b within the predetermined arrival time _t3 of the rolled material 1. The speed control device 210 is different from the other embodiments described above in that it has different calculation units 220a and 220b from those of the other embodiments described above. The other components are the same as those of the other embodiments, and the same components are denoted by the same symbols and detailed descriptions are appropriately omitted.

As shown in FIG3 , the motor speed control device 210 of this embodiment has operation units 220a and 220b. The operation unit 220a generates and outputs a speed reference pattern of the motor 3a on the upstream side, and the operation unit 220b generates and outputs a speed reference pattern of the motor 3b on the downstream side. The configurations of the operation units 220a and 220b are roughly the same, and the following is an explanation of the operation unit 220b on the downstream side. As in the case of the other embodiments described above, when the operation unit 220a is provided for the motor located at the most upstream side, it does not necessarily have to be the same as the configuration of the operation unit 220b.

The calculation unit 220b includes a power consumption calculation function 222. In this example, the difference from other implementations is that the calculation unit 220b includes an acceleration/deceleration rate calculation function 217 which is different from the above-mentioned other implementations, and the acceleration/deceleration rate calculation function 217 includes a power consumption calculation function 222.

The power consumption calculation function 222 calculates the power consumption J consumed within the scheduled arrival time _t3 based on the speed performance _N1 of the downstream motor 3b, the target conveying speed _N2 , the parameters of the motor, and the scheduled arrival time _t3 of the rolled material 1. The acceleration/deceleration time _t1 is a variable, and the power consumption calculation function 222 calculates the acceleration/deceleration time _t1 at which the power consumption J of the motor 3b reaches the minimum within the scheduled arrival time _t3 and outputs it.

The acceleration/deceleration rate calculation function 217 calculates the acceleration/deceleration rate α1 using the acceleration/deceleration time _t1 output by the power consumption calculation function 222, and outputs the calculated acceleration/deceleration rate _α1 .

If the power consumption calculation function 222 can calculate the power consumption J and the acceleration/deceleration time _t1 at which the power consumption J is minimized, it is not limited to being provided as a function of the acceleration/deceleration rate calculation function 217, and may be provided as a function independent of the acceleration/deceleration rate calculation function.

The operation of the speed control device 210 of this embodiment is described.

FIG. 4 is a schematic curve diagram for explaining the operation of the speed control device of this embodiment, and is an example of a curve diagram showing the time variation of the speed reference.

FIG4 shows a speed reference pattern N(t) generated by the speed reference calculation function 18 and outputted by the speed reference setting function 19b. In addition to the speed reference N, the vertical axis of FIG4 also shows the value _I12 of the quadratic value of the primary current of the motor ^3b , and the power consumption amounts _J1 and _J2 belonging to ^the time integral of _I12 are also shown in FIG4. In this embodiment, the power consumption amounts _J1 and _J2 change according to the change of the acceleration/deceleration rate _α1 , and there is an acceleration/deceleration time _t1 at which J= _J1 + _J2 is minimized. The speed control device 210 uses the acceleration/deceleration rate _α1 at this time to generate the speed reference pattern N(t) and output it.

In the present embodiment, the motor 3b is operated at a certain torque during acceleration and deceleration and t ₀ > 0. In the following description, unless otherwise specified, t ₃ ≧ t ₂ ≧ t ₀ is assumed. t ₀ is the fastest acceleration and deceleration time calculated by the mechanical elements using the motor 3b described in the other embodiments.

The acceleration/deceleration rate _α1 is calculated as follows.

α ₁ =(N ₂ -N ₁ )/t ₁

As shown in FIG4 , the mode N(t) includes data of the speed reference at each moment, similarly to the other embodiments described above. At the moment τ ₀ , the speed reference N is set to the speed performance N ₁ of the motor 3b on the downstream side. During the acceleration/deceleration time t ₁ between the moment τ ₀ and the moment τ ₁₁ , the mode N(t) rises linearly at the slope of the acceleration/deceleration rate α ₁ . At the moment τ ₁₁ , the mode N(t) reaches the target conveying speed N ₂ . Thereafter, during the time t ₂ from the moment τ ₁₁ to the moment τ ₂ , the mode N(t) changes at a constant target conveying speed N ₂ .

The power consumption amount _J1 is set to the power consumed during the acceleration/deceleration time _t1 from time _τ0 to time _τ11 , and the power consumption amount _J2 is set to the power consumed during the time _t2 from time _τ11 to time _τ2 .

The power consumption calculation function 222 calculates the power consumption J= _J1 + _J2 before the die-rolled material 1 reaches the predetermined time _t3 according to the following formula (2). For example, the power consumption calculation function 222 changes the acceleration/deceleration time _t1 at a certain time interval from _t0 to _t3 , calculates the power consumption J of each acceleration/deceleration time _t1 , and searches for the acceleration/deceleration time _t1 at which the power consumption J is minimized. The fastest acceleration/deceleration time _t0 is calculated by the acceleration/deceleration rate calculation function 217 using the formula (1) described in the other embodiments described above.

In method (2), inertial torque GD ² , rated torque _TA , rated torque current _IqA , torque equivalent to mechanical loss _Tm , exciting current _Id and DC resistance R caused by cables etc. are motor parameters, and pre-set values can be applied by the motor parameter setting function 16 .

The acceleration/deceleration rate calculation function 217 sets the acceleration/deceleration rate α ₁ after the acceleration/deceleration time t ₁ at which the power consumption J extracted by the power consumption calculation function 222 reaches the minimum.

The speed reference calculation function 18 generates and outputs a speed reference pattern N(t) based on the acceleration/deceleration rate α ₁ , the acceleration/deceleration time t ₁ , the speed performance N ₁ of the motor 3b and the target transport speed N ₂ output by the acceleration/deceleration rate calculation function 217. Thereafter, the calculation unit 220b supplies the speed reference pattern N(t) to the variable speed control device 4b via the speed reference setting function 19b, similarly to the case of the other embodiments described above.

In addition, equation (2) can be derived as follows.

The sum of the power consumption _J1 during the acceleration/deceleration time _t1 and _the power consumption J2 during the time _t2 from time _τ11 to time τ2 is calculated as the power consumption _J until the predetermined time _t3 . Since the power consumption _J1 and _J2 can be calculated using the following equations (3) and (4), the power consumption J can be calculated using equation (5).

First, the motor primary current _I1 of the motor 3b can be expressed by the following equation (6). Here, _Iq is the torque current.

Here, when the rated primary current of the motor 3b is set to _I1A and the rated torque current is set to _IqA , by substituting into the relationship of equation (6), the rated torque current _IqA can be expressed by the following equation (7).

Since the torque T and torque current _Iq of the motor have a proportional relationship, they can be expressed as shown in the following equations (8) and (9) using the rated torque _TA and rated torque current _IqA of the motor 3b.

According to the torque T _m equivalent to the mechanical loss and the torque current I _qM , the primary current I _1m equivalent to the mechanical loss can be expressed as shown in the following equations (10) and (11).

The expected arrival time _t3 is the sum of the acceleration/deceleration time _t1 and the time _t2 from time _τ11 to time _τ2 . Since the expected arrival time _t3 is set to be greater than the fastest acceleration/deceleration time _t0 , the relationship between _t1 to _t3 and _t0 can be expressed as the following formula (12) based on formula (1).

Since the torque T of the motor 3b during _the acceleration/deceleration time t1 can be obtained by replacing _kTA in the equation (12) with T, the acceleration/deceleration time _t1 can be expressed as shown in the following equation (13).

By substituting equation (9) into equation (13), equation (14) can be obtained which represents the relationship between the torque current _Iq and the acceleration/deceleration time _t1 .

The time _t2 can be expressed from equation (12) by the following equation (15).

t ₂ =t ₃ -t ₁ (15)

By substituting equations (14) and (15) into equation (5), equation (2) can be obtained. In this way, the power consumption J within the predetermined time _t3 can be expressed as a function of the acceleration/deceleration time _t1 .

The effect of the speed control device 210 of the motor of this embodiment is described.

The speed control device 210 of this embodiment has a calculation unit 220b. The calculation unit 220b includes an acceleration/deceleration rate calculation function 217 and a power consumption calculation function 222. The acceleration/deceleration rate calculation function 217 and the power consumption calculation function 222 calculate the power consumption J consumed by the downstream motor 3b within the scheduled arrival time _t3 of the rolled material 1 reaching the downstream conveying table 102. The acceleration/deceleration rate calculation function 217 and the power consumption calculation function 222 calculate the acceleration/deceleration time _t1 at which the power consumption J consumed by the motor 3b within the scheduled arrival time _t3 reaches the minimum, and extract it to calculate the acceleration/deceleration rate _α1 . The calculation unit 220b generates a speed reference pattern N(t) based on the calculated acceleration/deceleration rate _α1 and outputs it. Therefore, it is possible to suppress an increase in power consumption during acceleration and deceleration operation of the motor 3 b on the downstream side, and to realize speed control that matches the conveyance speed of the rolled material 1.

The above-mentioned embodiments have been described for the case of two adjacent conveyor tables, but the above-mentioned speed control method is not limited to the case between two adjacent conveyor tables. For example, among three conveyor tables, the target conveying speed of the most downstream conveyor table can be matched with the speed of the most upstream conveyor table. In the above-mentioned example, when the speed of the middle conveyor table is roughly the same as the speed of the most upstream conveyor table, the target conveying speed of the most downstream conveyor table is determined according to the speed of the most upstream conveyor table. Furthermore, in the above-mentioned case, it can also be constructed so that the speed is calculated by the position detector set according to each conveyor table, and the target conveying speed of the most downstream conveyor table is calculated again according to each conveyor table.

In the above, different embodiments 1 and 2 have been described respectively, but these embodiments may be combined. That is, it is also possible to construct a configuration in which, after generating a pattern including a speed reference including an acceleration/deceleration rate determined in a manner to minimize the power consumption J, the speed of the upstream motor 3a is corrected according to the relationship between the speed of the upstream motor 3a and the predetermined time _t3 .

In each of the above-mentioned embodiments, the speed control device 10, 210 may also be constructed to include the functions constituting the operation unit 20a, 20b, 220b, for example, by hardware according to each function, or by software that implements the actions of each function. The speed control device 10, 210 is, for example, a computer device that has software or a program that implements the actions of each function illustrated and described, and the computer device may also be a programmable logic controller, etc.

When the speed control device 10, 210 of the implementation type is implemented by a computer device, for example, the operation units 20a, 20b, 220a, 220b are implemented by an operation processing device (CPU), and have a memory means for storing programs to read and execute them sequentially, and the program includes one or more steps for executing the actions of each function shown in Figure 1 or Figure 3. The above-mentioned implementation types have two operation units, but different CPUs can also be used to implement the two operation units, and of course, one CPU can also be used to implement them.

As described above, a motor speed control device can be implemented to prevent the pressed and rolled material from slipping when the conveying table moves.

Several embodiments of the present invention have been described above. These embodiments are provided as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms and can be omitted, replaced, and modified in various ways without departing from the gist of the invention. These embodiments and their variations are included in the scope and gist of the invention and are also included in the scope of the invention and its equivalents described in the scope of the patent application. Furthermore, the aforementioned embodiments can be implemented in combination with each other.

1: Pressed and rolled materials

2a to 2e: conveyor rollers

3a,3b: Electric motor

4a,4b: Variable speed control device

5a,5b: Position detector

10: Speed control device

14: Target transport speed calculation function

15: Calculation function for the arrival time of rolled materials

16: Motor parameter setting function

17: Acceleration and deceleration rate calculation function

18: Speed-based calculation function

19a,19b: Speed benchmark setting function

21: Upstream motor speed correction function

20a, 20b: Operational unit

100,102:Transport table

Da, Db: Position detection signal

N ₁ : Speed performance

N ₂ : Target transport speed

N _C : Correction value

N(t): Mode

N _U :Speed Performance

t ₀ : Fastest acceleration/deceleration time

t ₃ : Arrive at scheduled time

GD ² : Inertial moment

T _A : Rated torque

α: acceleration and deceleration rate

Claims (6)

A motor speed control device comprises: a first operation means for supplying a first speed reference to a first variable speed control device, and the first variable speed control device controls the speed of a first motor driving a table roller of a first conveying table; and a second operation means for supplying a second speed reference to a second variable speed control device, and the second variable speed control device controls the speed of a second motor driving a table roller of a second conveying table, wherein the second conveying table is arranged downstream of the first conveying table, and the second The calculation means calculates the conveying speed of the rolled material conveyed by the first conveying table as the target conveying speed converted into the speed of the second motor, and calculates the fastest acceleration and deceleration time according to the speed performance data of the second motor, the target conveying speed, and the pre-set motor parameters of the second motor, and generates a speed reference pattern according to the speed performance data, the target conveying speed, and the fastest acceleration and deceleration time as the second speed reference to be supplied to the second variable speed control device. The speed control device of the motor as described in claim 1, wherein the second calculation means calculates the expected arrival time of the rolled material to the second conveyor table according to the target conveying speed and the distance between the first conveyor table and the second conveyor table, and the speed control device of the motor further has an upstream motor speed correction means, which corrects the first speed standard according to the fastest acceleration/deceleration time and the expected arrival time. When the expected arrival time is shorter than the fastest acceleration/deceleration time, the upstream motor speed correction means outputs a correction value in such a way that the expected arrival time becomes longer than the fastest acceleration/deceleration time. The first calculation means generates a new speed standard according to the first speed standard and the correction value and outputs it. The speed control device of the motor as described in claim 2, wherein in the upstream motor speed correction means, the correction value is pre-set according to the speed of the first motor. The speed control device of the motor as described in claim 1, wherein the second calculation means further comprises a power consumption calculation means, which calculates the expected arrival time of the rolled material to the second conveyor table according to the target conveying speed and the distance between the first conveyor table and the second conveyor table, and calculates the power consumption of the second motor within the expected arrival time according to the acceleration/deceleration time in the range from the fastest acceleration/deceleration time to the expected arrival time, the target conveying speed, the speed performance data and the motor parameters. The speed control device of the motor as described in claim 4, wherein the power consumption calculation means is to set the acceleration and deceleration time to a plurality of values from the fastest acceleration and deceleration time to the predetermined time, and extract the minimum value from the values obtained by calculating the power consumption of the second motor for each of the plurality of values. The speed control device of the motor as described in claim 2, wherein the second calculation means further comprises a power consumption calculation means, which calculates the expected arrival time of the rolled material to the second conveyor table according to the target conveying speed and the distance between the first conveyor table and the second conveyor table, and calculates the power consumption of the second motor within the expected arrival time according to the acceleration/deceleration time in the range from the fastest acceleration/deceleration time to the expected arrival time, the target conveying speed, the speed performance data and the motor parameters.

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