Motor driver for continuous casting machine

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a motor driver for a continuous casting machine used for controlling a motor for driving a load associated with a continuous casting machine used for casting iron or the like.

【0002】

[Conventional technology]

For example, in a facility that continuously manufactures slabs such as billets and slabs by a continuous casting machine, the width of the mold installed in the continuous casting machine is set to the width of the mold in order to cope with the change in the slab size. A structure that can be changed in the installed state is adopted, and in this case, it is common to use an electro-hydraulic servo cylinder to linearly move the short side portion of the mold. Further, in the continuous casting equipment, an electro-hydraulic servo cylinder is also used for driving a turn dish stopper, driving a sliding nozzle for a turn dish, driving a mechanism for applying vibration to a mold, and the like.

【0003】

FIG. 5 substantially shows a general system configuration example of the drive system of the electro-hydraulic servo cylinder as described above. In FIG. 5, a variable relaxation type stepping motor 2 is used to drive the electro-hydraulic servo cylinder 1. The motor driver 3 performs open-loop control in which the stepping motor 2 is rotated by an amount proportional to the number of input of position command pulses given by the host controller, and in the servo cylinder 1 in response to such rotation. The hydraulic control valve is displaced and the hydraulic cylinder is linearly moved. The amount of movement of the hydraulic cylinder at this time is proportional to the amount of rotation of the stepping motor 2.

【0004】

In the above system, since open loop control is performed, the stepping motor 2 is likely to be out of sync (out of synchronization) due to the influence of momentary overload or load fluctuation. In this case, a system that does not detect step-out is also provided, but FIG. 5 shows an example in which means are provided to detect step-out. Specifically, the detector 4 is connected to, for example, the rear part of the stepping motor 2 and outputs a detection pulse proportional to the amount of rotation of the motor 2. Further, the step-out detection circuit 5 compares the phase difference between the position command pulse and the detection pulse, and determines that the stepping motor 2 is step-out when the difference becomes equal to or more than a predetermined value, and determines that the stepping motor 2 is step-out. It is configured to transmit a step-out detection signal to, which makes it possible for the host controller to deal with the abnormal state of step-out of the stepping motor 2 at an early stage.

[Problems to be Solved by the Invention]

The stepping motor 2 has a characteristic that self-heating is large because it is necessary to pass an exciting current even when the stepping motor 2 is stopped. In addition, the inside of the continuous casting machine corresponds to the worst environment in the steel mill, and there is a situation that the temperature rise of the equipment used becomes extremely large. As a result, the stepping motor 2 becomes extremely hot due to the effects of both the temperature of the installation atmosphere and self-heating, and as a result, it is inevitable that the life of the stepping motor 2 will be shortened, and the maintenance frequency will increase. There is.

【0005】

Further, since the stepping motor 2 has an open-loop control configuration, as described above, there is a high possibility that step-out will occur due to the influence of a momentary overload or load fluctuation. When the stepping motor 2 is stepped out in this way, the control position (cylinder position) of the electro-hydraulic servo cylinder 1 cannot be grasped on the upper controller side, so if production is continued as it is, a defective product can be manufactured. In the worst case, there is a risk of damaging the equipment. Therefore, as shown in the configuration example shown in FIG. 5, a step-out detection function is provided to detect the occurrence of an abnormal state, but when the step-out of the stepping motor 2 is detected, the continuous casting machine is used. It is necessary to take the procedure of measuring the cylinder position with the operation temporarily stopped, confirming the cylinder position, and then restarting the operation of the continuous casting machine, which is a problem that the productivity of the slab is inevitably reduced. was there.

【0006】

In order to deal with the above problems, by using a closed-loop control type synchronous servomotor to drive the electro-hydraulic servo cylinder 1, the exciting current when the motor is stopped is reduced and the motor itself It is possible to make a highly reliable system that suppresses heat generation and does not cause step-out. However, when performing such closed-loop control, a detector for feeding back the rotational position is required in the servo motor, so the number of parts is larger than that of the stepping motor, and a failure occurs by that amount. The probability of In particular, when a failure occurs in the detector, the drive control of the electro-hydraulic servo cylinder 1 becomes impossible, so that the production must be stopped until the failure of the detector is recovered, which causes a significant decrease in productivity. It will be.

【0007】

On the other hand, the equipment installed in the continuous casting machine, which is one of the worst environmental places in the steel mill, needs to be maintained in a relatively short cycle. Therefore, in reality, for a set of electric devices such as a motor driver installed at a position away from the continuous casting machine, a plurality of devices such as an electro-hydraulic servo cylinder installed in the continuous casting machine and a motor attached thereto are used. A set is prepared, and these are carried around and used while being maintained in sequence. Therefore, when constructing a system in which the drive source of the electro-hydraulic servo cylinder 1 is changed from the stepping motor 2 to the synchronous servo motor, a large number of motors and their associated detectors must be replaced at the same time. For this reason, it becomes necessary to dispose of a large amount of existing equipment that can still be used, and it is inevitable that a large amount of cost will be incurred in purchasing equipment such as newly introduced servo motors and detectors. Therefore, there is a practical problem that it is very difficult to change the drive source of the electro-hydraulic servo cylinder 1 from the stepping motor 2 to the servo motor to improve productivity and extend the motor life. It was.

【0008】

The present invention has been made in view of the above circumstances, and an object of the present invention is to change the drive source of a servo cylinder installed in a continuous casting machine from a stepping motor to a synchronous servo motor controlled by a closed loop. The purpose of the present invention is to provide a motor driver for a steel mill, which can perform the change work effectively without discarding the existing equipment and at the same time can improve the reliability.

【0009】

[Means for solving problems]

The means described in claim 1 can be adopted to achieve the above object. According to this means, the switching means controls the control means in the first control mode and the second control based on the result of automatically determining the connected motor type based on the difference in the number of winding phases or the winding impedance or the manual operation. The operation of selectively switching to any of the modes is performed. When the control means is switched to the first control mode, the stepping motor for driving the servo cylinder is open-loop controlled based on a position command given from the outside, and the control means is switched to the second control mode. Then, the synchronous servomotor for driving the servo cylinder is closed-loop controlled based on the position command and the output from the rotation position detector for detecting the rotation position of the servomotor.

【0010】

Therefore, by replacing the existing stepping motor with a synchronous servomotor controlled by a closed loop, the drive source of the servo cylinder is reduced in productivity in the continuous casting machine due to the occurrence of step-out in the motor as the drive source. In the case of realizing a system capable of preventing the above, both the stepping motor and the servo motor can be driven by the same motor driver. In this case, in the continuous casting machine, a plurality of sets of equipment such as stepping motors are prepared because the maintenance needs to be performed in a relatively short cycle. However, when the above motor driver is installed, they are prepared. Instead of discarding the stepping motors at the same time, it is sufficient to replace the stepping motors with servo motors in order from the one whose life has expired. As a result, it is not necessary to dispose of a large amount of existing stepping motors that can still be used when changing the motor type in order to improve the productivity of the continuous casting machine and extend the motor life. The resources can be used effectively, the required cost can be suppressed, and the motor type can be easily changed.

【0011】

According to the means according to claim 2, since the synchronous servomotor can be open-loop controlled based on the position command, the actual usage mode can be diversified.

【0012】

According to the means according to claim 3, step-out detection in a state where the synchronous servomotor is open-loop controlled can be performed by using an existing step-out detection circuit in the system to be installed.

【0013】

According to the means according to claim 4, in the unlikely event that an output abnormality occurs in the rotation position detector due to disconnection of the signal line or the like, it is possible to shift to the third control mode in which the servomotor is open-loop controlled. Therefore, the reliability against failure is improved, which is beneficial in preventing a decrease in productivity in the continuous casting machine.

【0014】

According to the means according to claim 5, during open loop control of a stepping motor or a servomotor, the exciting current supplied to the motors is automatically reduced while the motors are stopped rotating. Therefore, it is possible to suppress the temperature rise of stepping motors and servomotors installed in a high temperature atmosphere as much as possible, and as a result, it is possible to contribute to prolonging the life of these motors.

【0015】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment in which the present invention is applied to a motor driver for an electro-hydraulic servo cylinder for adjusting the mold width installed in a continuous casting machine will be described with reference to FIGS. 1 to 4. Figure 1 shows the overall electrical configuration by a combination of functional blocks. In FIG. 1, the stepping motor 12 was originally provided to drive, for example, an electro-hydraulic servo cylinder (indicated by reference numeral 11 in FIGS. 2 to 4) for a mold width variable unit in a continuous casting machine. For example, a 5-phase variable relaxation type is used. The stepping motor 12 may or may not be provided with a detector 13 for step-out detection (corresponding to a pulse generator for rotation detection in the present invention). As 13, for example, it is common to use a rotary encoder that generates 20 pulses / time of detection pulses.

【0016】

The synchronous servomotor 14 provided in place of the stepping motor 2 for driving the mold width variable unit is, for example, a four-phase one, and is a detector 15 for detecting the rotation position (rotation position in the present invention). (Equivalent to a detector) is built-in. Similar to the synchronous servomotor 14, the detector 15 is configured by combining an iron core and a coil (not including electronic components), and is, for example, a variable reluctance commercially available as an absorber (registered trademark name). A resistance type absolute rotation position detector is used. Here, the detector 15 composed of the absorber is the first and second primary coils that are separately excited by the first and second AC signals (sine wave signal sinωt and cosine wave signal cosωt) that are out of phase with each other. , Phase modulation signal (sin (ωt-θ) according to the rotation position of the detection shaft in the excited state of these primary coils ) Is provided, and the phase modulation signal is output as an absolute position signal indicating the rotation position of the synchronous servomotor 14. In this case, a resolver, a synchro, or the like can be used as the detector 15. In FIG. 1, the stepping motor 12 and related elements are referred to as "4-phase motor" and "for 4-phase", and the synchronous servo motor 14 and related elements are referred to as "5-phase motor". , "For 5 phases" is written.

【0017】

A terminal block 17 for control output is connected to the motor driver 16 according to the present invention, and either one of the stepping motor 12 and the synchronous servo motor 14 is connected to the terminal block 17. In the state where the 4-phase servomotor 14 is connected, an empty terminal is generated in the terminal block 17. It is also possible to replace the terminal block 17 with a connector.

【0018】

The motor driver 16 is composed of a current control unit 18, a position detection unit 19, a close control unit 20, an open control unit 21, and a switching control unit 22 (corresponding to the switching means in the present invention). In this case, the current control unit 18, the position detection unit 19, the close control unit 20, and the open control unit 21 constitute the control means referred to in the present invention.

【0019】

The current control unit 18 responds to the constant current circuit 18a for outputting each phase exciting current for a maximum of five phases through the terminal block 17 and the current command value I given from the closed control unit 20 or the open control unit 21. The configuration is provided with each phase distributor 18b for determining each phase current value Ia to Ie. In this case, each phase distributor 18b is a function Pa (θ) to Pe (θ) to Pe (function) of the current command value I and the rotation position data θ (electric angle) indicating the rotation position of the motor (stepping motor 12 or synchronous servo motor 14). Each phase current value Ia to Ie obtained by the product of θ) is given to the constant current circuit 18a as a current command value, and the constant current circuit 18a is a level corresponding to the given current command value (Ia to Ie). It is configured to output the exciting current of each phase of the phase. The rotation position data θ is input as a function of a position command pulse given by the host controller when the motor is open-loop controlled, and indicates the rotation position of the motor when the motor is closed-loop controlled. It will be input as a function of the position detection pulse (which is output from the position detection unit 19 as described later).

【0020】

The position detection unit 19 includes a position data conversion circuit 19a that generates a position detection pulse (incremental pulse) indicating the rotation position of the synchronous servomotor 14 based on the phase modulation signal output from the detector 15, and a position detection thereof. The configuration is provided with a scale conversion circuit 19b that converts the pulses into the same number of pulses as the detection pulses generated by the detector 13 used in the stepping motor 12 and outputs them. The position detection pulse from the position data conversion circuit 19a is given to the current control unit 18 as the rotation position data θ at the time of closed loop control of the synchronous servomotor 14, and is always given to the close control unit 20. .. Further, although not shown, the position detection unit 19 is provided with an abnormality detection function for detecting an abnormality in the detector 15 or a disconnection of a signal line for the detector 15, and when an abnormality is detected, It is configured to give an abnormal signal to the switching control unit 22.

【0021】

The close control unit 20 has a configuration including the following circuit elements. That is, the subtraction unit 20a outputs the deviation between the position command pulse from the host controller and the position detection pulse from the position detection unit 19. The operational amplifier 20b outputs the product of the deviation obtained by the subtraction unit 20a and the preset position-proportional gain as a speed command. The speed detection circuit 20c outputs a speed feedback value according to the rotation speed of the synchronous servomotor 14 based on the position detection pulse from the position detection unit 19. The subtraction unit 20d outputs the deviation of the speed command and the speed feedback value. The operational amplifier 20e outputs the product of the value obtained by integrating and controlling the deviation obtained by the subtraction unit 20d and the preset speed proportional gain as the current command value I. The comparator 20f generates a step-out detection signal and transmits it to the host controller when the position deviation obtained by the subtraction unit 20a exceeds a preset reference value.

【0022】

The open control unit 21 can be switched to either "4-phase mode" or "5-phase mode" by a command from the switching control unit 22, and has a configuration including the following circuit elements. .. That is, the storage unit 21a stores the 4-phase current command value and the 5-phase current command value when the stepping motor 12 and the synchronous servo motor 14 are controlled in open loop, respectively, and switches to the "4-phase mode". The 4-phase current command value is output in the state of being set, and the 5-phase current command value is output in the state of being switched to the "5-phase mode".

【0023】

When the motor to be controlled is rotating, the current reduction control unit 21b outputs each phase current command value output from the storage unit 21a as the current command value I, and the motor is stopped rotating. Occasionally, it is output as the current command value I in a state where the current command value for each phase is reduced to a preset level. The current reduction control unit 21b determines, for example, that the motor to be controlled has stopped when the position command pulse from the host controller is not continuously given to the open control unit 21 for a predetermined time or longer. It has become.

【0024】

The scale conversion unit 21c is for scale-converting the position command pulse from the host controller into the position command pulse corresponding to each excitation sequence at the time of open loop control of the stepping motor 12 and the synchronous servo motor 14. The position command pulse for the synchronous servomotor 14 is output as the rotation position data θ in the state of being switched to the "4-phase mode", and the position command pulse for the stepping motor 12 is output in the state of being switched to the "5-phase mode". Is output as the rotation position data θ. The rotation position data θ is given to the current control unit 18 during open loop control of the motor.

【0025】

The switching control unit 22 has a configuration including the following circuit elements. That is, the 4-phase motor close control unit 22a holds the switch elements SW1, SW2, and SW3 in the closed loop control switching state (the state in which the contacts (ca) are turned on) as shown in the figure when operated. In this switching state, the position command pulse from the host controller is given to the close control unit 20, and the current command value I from the close control unit 20 and the rotation position data θ from the position detection unit 19 are given to the current control unit 18. Position detection pulse) will be given.

【0026】

The 4-phase motor open control unit 22b holds the switch elements SW1, SW2, and SW3 in an open-loop control switching state (a state in which each contact (cb) is turned on) that is inverted from the state shown in the figure when operated. At the same time, the open control unit 21 is switched to the "4-phase mode". In such a switching state, a position command pulse from the host controller is given to the open control unit 21, and is output to the current control unit 18 from the storage unit 21a in the open control unit 21 through the current reduction control unit 21b. The current command value I for 4 phases and the rotation position data θ for 4 phases (position command pulse for synchronous servomotor 14) output through the scale conversion unit 21c in the open control unit 21 are given. Become.

【0027】

The 5-phase motor open control unit 22c holds the switch elements SW1, SW2, and SW3 in the open loop control switching state (the state in which each contact (cb) is turned on) when operated, and the open control unit 21. To "5-phase mode". In such a switching state, a position command pulse from the host controller is given to the open control unit 21, and is output to the current control unit 18 from the storage unit 21a in the open control unit 21 through the current reduction control unit 21b. The current command value I for the 5-phase and the rotation position data θ (position command pulse for the stepping motor 12) for the 5-phase output through the scale conversion unit 21c in the open control unit 21 are given.

【0028】

The motor type detection unit 22d detects the type of motor connected to the terminal block 17 through the current control unit 18. In this embodiment, since the stepping motor 12 and the synchronous servomotor 14 connected to the terminal block 17 have different numbers of phases, the type of motor can be detected by examining the difference in the number of phases through the current control unit 18. Then, when the motor type detection unit 22d detects that the stepping motor 12 is connected to the terminal block 17, the 5-phase motor open control unit 22c is switched to the operating state, and is synchronized with the terminal block 17. When it is detected that the servo motor 14 is connected, the detector failure detection unit 22e is switched to the operating state.

【0029】

When the position detection unit 19 does not detect an abnormality (such as a disconnection of a signal line) of the detector 15 in a state of being operated by the motor type detection unit 22d, the detector failure detection unit 22e is described as described above. The 4-phase motor close control unit 22a is switched to the operating state, but when the position detection unit 19 detects an abnormality in the detector 15, the 4-phase motor close control unit 22a is stopped and the 4-phase motor open control unit 22b is stopped. To the operating state.

【0030】

In this case, the switching control unit 22 automatically performs an operation of detecting the type of the motor connected to the terminal block 17 by the motor type detection unit 22d when there is no manual operation from the outside, and the detection result is obtained. And, based on the detection result of the detector failure detection unit 22e, any one of the 4-phase motor close control unit 22a, the 4-phase motor open control unit 22b, and the 5-phase motor open control unit 22c is selectively operated. Although "automatic selection operation" is performed, the functions of the motor type detection unit 22d and the detector failure detection unit 22e are disabled according to the manual operation from the outside, and the 4-phase motor close control is performed in this disabled state. It is also possible to perform a "manual selection operation" in which any one of the unit 22a, the 4-phase motor open control unit 22b, and the 5-phase motor open control unit 22c is selectively operated.

【0031】

Here, as described above, the control means according to the present invention is configured by the current control unit 18, the position detection unit 19, the close control unit 20, and the open control unit 21. In the present invention, the switch elements SW1, SW2, and SW3 are in the open loop control switching state (the states where each contact (cb) is turned on) and the open control unit 21 is switched to the "5-phase mode". It corresponds to the first control mode. Further, the state in which the switch elements SW1, SW2, and SW3 are in the closed loop control switching state (the state in which each contact (ca) is turned on) corresponds to the second control mode referred to in the present invention, and further, the switch. The state in which the elements SW1, SW2, and SW3 are switched to the open loop control switching state and the open control unit 21 is switched to the "four-phase mode" corresponds to the third control mode in the present invention.

【0032】

In this embodiment configured as described above, the motor driver 16 operates as described below. As shown in FIG. 2, when a 5-phase stepping motor 12 equipped with a detector 13 is connected to the motor driver 16, that is, an existing stepping provided for a mold width variable unit in a continuous casting machine. When the motor 12 is the drive target ... In this case, each phase coil of the stepping motor 12 is connected to the terminal block 17, and the detector 13 detects the detection pulse of the existing step-out. It is connected so as to be given to the circuit 23, and the step-out detection signal from the step-out detection circuit 23 is given to the host controller. In this case, the "manual selection operation" function of the switching control unit 22 is used to operate the 5-phase motor open control unit 22c in the switching control unit 22, or to perform switching control without performing manual operation from the outside. The unit 22 is made to execute the "automatic selection operation" function, and the 5-phase motor open control unit 22c is operated by such a function.

【0033】

When the 5-phase motor open control unit 22c is operated, the switch elements SW1, SW2, and SW3 are held in the open loop control switching state (the state in which each contact (cb) is turned on), and the open control unit 21 is operated. It can be switched to "5-phase mode". Therefore, the current command value I for 5 phases is output from the storage unit 21a through the current reduction control unit 22b, and the position command pulse by the host controller is converted into the position command pulse for the stepping motor 12 from the scale conversion unit 21c. The rotation position data θ is output, and the current command value I and the rotation position data θ are given to the current control unit 18.

【0034】

Therefore, the current control unit 18 drives the stepping motor 12 based on the current command value I and the rotation position data θ to rotate the stepping motor 12 to a control position corresponding to the position command pulse from the host controller. Will be. In this case, when the stepping motor 12 is stopped at the control position, the current reduction control unit 21b reduces the current command value I to the set level, and the exciting current supplied to the stepping motor 12 corresponds to this. It will be reduced. In this case, the self-heating when the stepping motor 12 is stopped is mostly due to resistance loss. Therefore, when the above setting level is, for example, 80%, the self-heating amount is reduced to about 0.64 times, which is the setting level. For example, when it is 50%, the self-calorific value is reduced to about 0.25 times.

【0035】

In the configuration example shown in FIG. 2, a state in which a detector 13 composed of a rotary encoder is provided for detecting step-out of the stepping motor 12, but as shown in FIG. 3, this detector 13 is used. It can also be replaced with a detector 15'(for example, a variable reluctance type absolute rotation position detector) similar to the detector 15 for the synchronous servomotor 14.

【0036】

In this case, each phase coil of the stepping motor 12 is connected to the terminal block 17, and the detector 15'is connected so as to give the output to the position detection unit 19 in the motor driver 16. Further, the detection pulse output from the scale conversion circuit 19b in the position detection unit 19 is connected so as to be given to the existing step-out detection circuit 23, and the step-out detection signal from the step-out detection circuit 23 is connected. Will be given to the host controller.

【0037】

In such a configuration, in the position detection unit 19, the position data conversion circuit 19a generates a position detection pulse indicating the rotation position of the stepping motor 12 based on the phase modulation signal output from the detector 15'. As a result, the scale conversion circuit 19b that receives this converts the position detection pulse into the same number of pulses as the detection pulse generated by the detector 13 and outputs the pulse, so that the existing step-out detection circuit There is no problem even if 23 is used.

【0038】

As shown in FIG. 4, when a 4-phase synchronous servomotor 14 is connected to the motor driver 16, that is, a synchronous servomotor 14 capable of closed-loop control instead of the existing stepping motor 12 is driven. In this case, each phase coil of the synchronous servomotor 14 is connected to the terminal block 17, and the detector 15 outputs the output to the position detector 19 in the motor driver 16. Connected to give to. In this case, the "manual selection operation" function of the switching control unit 22 is used to operate the 4-phase motor close control unit 22a in the switching control unit 22, or to perform switching control without performing a manual operation from the outside. The "automatic selection operation" function is executed by the unit 22, and when the position detection unit 19 does not output an abnormal signal at this time, the 4-phase motor close control unit 22a is operated by the "automatic selection operation" function. It works. It is also possible to operate the 4-phase motor open control unit 22b by the "manual selection operation" function, and when an abnormal signal is output from the position detection unit 19, the above "automatic selection operation" function is used. The 4-phase motor open control unit 22b is operated.

【0039】

When the 4-phase motor close control unit 22a is operated, the switch elements SW1, SW2, and SW3 are held in the closed loop control switching state (the state in which each contact (ca) is turned on). Therefore, the close control unit 20 outputs a current command value I at a level corresponding to the deviation between the position command pulse from the host controller and the position detection pulse from the position data conversion circuit 19a in the position detection unit 19. Along with being given to the current control unit 18, the position detection pulse from the position data conversion circuit 19a is given to the current control unit 18 as rotation position data θ.

【0040】

Therefore, the current control unit 18 drives the synchronous servomotor 14 while performing feedback control based on the current command value I and the rotation position data θ, so that the servomotor 14 responds to the position command pulse from the host controller. It will be rotated to the control position. In this case, when the synchronous servomotor 14 is stopped at the control position, the current command value I becomes zero, so that the self-heating of the servomotor 14 is suppressed. Further, the comparator 20f in the close control unit 20 generates a step-out detection signal when the deviation from the position command pulse and the position detection pulse obtained by the subtraction unit 20a exceeds a preset reference value. Performs the operation of sending to the host controller.

【0041】

When the 4-phase motor open control unit 22b is operated (manual operation or when it is operated based on an abnormal signal from the position detection unit 19), the switch elements SW1, SW2, and SW3 are in the open-loop control switching state. (The state where each contact (cb) is turned on) is held, and the open control unit 21 is switched to the "4-phase mode". Therefore, the current command value I for four phases is output from the storage unit 21a through the current reduction control unit 22b, and the position command pulse by the host controller is transmitted from the scale conversion unit 21c to the position command pulse for the synchronous servomotor 14. The rotation position data θ converted to is output, and the current command value I and the rotation position data θ are given to the current control unit 18.

【0042】

Therefore, the current control unit 18 drives the synchronous servomotor 14 based on the current command value I and the rotation position data θ, so that the servomotor 14 is moved to the control position according to the position command pulse from the host controller. It will rotate. In this case, when the synchronous servomotor 14 is stopped at the control position, the current command value I is reduced to the set level, and the exciting current supplied to the synchronous servomotor 14 is reduced accordingly. As a result, the amount of self-heating of the servomotor 14 can be reduced.

【0043】

In short, when the motor driver 16 according to the above embodiment is installed for driving the electro-hydraulic servo cylinder for adjusting the mold width installed in the continuous casting machine, the following effects are obtained. ..

【0044】

That is, according to the configuration of this embodiment, the drive source of the electro-hydraulic servo cylinder 11 is replaced with a synchronous servo motor 14 controlled by a closed loop from the existing stepping motor 12, so that the motor becomes the drive source. When realizing a system that can prevent a decrease in productivity in a continuous casting machine due to the occurrence of step-out, the same motor driver 16 can drive both the stepping motor 12 and the synchronous servo motor 14. .. In this case, in the continuous casting machine, a plurality of sets of devices such as the stepping motor 12 are prepared because the maintenance needs to be performed in a relatively short cycle. However, when the above motor driver 16 is installed, the continuous casting machine is prepared. Instead of discarding these stepping motors 12 at the same time, it is sufficient to replace them with synchronous servomotors 14 in order from the one whose life has expired. As a result, when changing the motor type in order to improve the productivity of the continuous casting machine and extend the motor life, it is not necessary to dispose of a large amount of the existing stepping motor 12 that can still be used. Can be effectively used, the required cost can be suppressed, and the motor type can be easily changed.

【0045】

Moreover, in order to control the synchronous servomotor 14 in a closed loop, the detector 15 provided inside the synchronous servomotor 14 is composed of a combination of an iron core and a coil and has excellent heat resistance. Therefore, the reliability of the closed loop control is reliable. The productivity will be improved, and thus the decrease in productivity can be prevented. In addition, in the unlikely event that an abnormality such as a signal line disconnection occurs in the detector 15, the synchronous servomotor 14 is automatically shifted to the open-loop control state, so that the reliability against failure is also improved. This is beneficial in preventing a decline in productivity. Further, in a state where the stepping motor 12 and the synchronous servo motor 14 are open-loop controlled, the exciting current is automatically reduced when the motor is stopped rotating, so that the motor is installed in a high temperature atmosphere. The temperature rise of the stepping motor 12 and the synchronous servo motor 14 can be suppressed as much as possible, and as a result, the life of the stepping motor 12 and the synchronous servo motor 14 can be extended.

【0046】

The present invention is not limited to the above embodiment, and can be expanded and modified as described below. The motors to be driven are the stepping motor 12 and the synchronous servomotor 14 having different phases, but the motors to be driven may have the same number of phases. In this case, the switching control unit 22 cannot determine the type of motor connected to the terminal block 17 based on the difference in the number of phases, but the constant current circuit 18b in the current control unit 18 is commanded. Since the winding voltage of each phase of the motor is controlled so as to be a current, the winding impedance of each motor can be known, and the type of connected motor can be determined based on such a difference in winding impedance. Therefore, there is no problem in the system configuration.

【0047】

The motor driver 16 is used not only for driving an electro-hydraulic servo cylinder for adjusting the mold width, but also for a turn dish stopper provided in a continuous casting facility, a sliding nozzle for a turn dish, a mechanism for applying vibration to a mold, and the like. It can also be used when driving a hydraulic servo cylinder.

[Simple explanation of drawings]

[Figure 1]

Functional block diagram showing an electrical configuration of an embodiment of the present invention [Figure 2]

Figure 1 that shows an actual system example in substance [Fig. 3]

Figure 2 that shows an actual system configuration example in substance [Fig. 4]

Figure 3 that shows an actual system configuration example in substance [Fig. 5]

Diagram showing a conventional system configuration example in substance [Explanation of symbols]

11 is an electro-hydraulic servo cylinder, 12 is a stepping motor, 13 is a detector (pulse generator for rotation detection), 14 is a synchronous servo motor, 15 is a detector (rotation position detector), 16 is a motor driver, 18 is The current control unit, 19 is a position detection unit, 19b is a scale conversion circuit, 20 is a closed control unit, 21 is an open control unit, and 22 is a switching control unit (switching means).