JP2002052591A - Motor controller for injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller capable of preventing a runaway of a motor used for an injection molding machine. SOLUTION: First and second three-phase inverters 12 and 13 having self- diagnosing circuits are respectively connected to three-phase windings of a three-phase double winding motor 11, and servo controllers 14 and 15 having self-diagnosing circuits are respectively connected to the three-phase inverters. If a fault occurs in the inverter 12 or the controller 32, the fault of the controller 33 is notified or if a fault occurs in the controller 33, the fault of the controller 33 is notified, and a rotation of the motor 11 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor control device for an injection molding machine, and more particularly to a motor control device for an injection molding machine for controlling a servomotor used in an electric injection molding machine or a hybrid molding machine. .

[0002]

2. Description of the Related Art Driving systems of an injection molding machine are roughly classified into a hydraulic system and an electric system. Previously, the hydraulic system was the mainstream, but now, the electric system, which has the features of high rigidity of the power transmission mechanism, good controllability of the position and speed of the movable part, and high energy conversion efficiency, It is becoming mainstream. Also, the hydraulic system has a feature that the power control of the drive unit can be easily and accurately performed, which is not provided by the electric system. Therefore, a hybrid system combining the electric system and the hydraulic system has been developed.

FIG. 5 shows the structure of a general electric injection molding machine. The electric injection molding machine includes a hopper 51 for temporarily storing the raw material, a heating cylinder 52 for plasticizing the raw material supplied from the hopper 51, and a raw material stored in the hopper 51 which is measured and supplied to the heating cylinder 52. At the same time, an injection device 54 including a screw 53 for injecting the raw material plasticized by the heating cylinder 52, and a fixed platen 5 to which dies 55 and 56 are respectively attached.
7 and a movable platen 58, a toggle link 59 for moving the movable platen 58, and a mold clamping mechanism 61 including a tie bar 60 for guiding the movable platen 58 and restricting the moving direction. The electric injection molding machine includes an injection motor 62 for moving the screw 53 back and forth, and a measuring motor 6 for rotating the screw 53.
3. An injection device moving motor 64 for moving the entire injection device 54 back and forth, a mold opening / closing motor 65 for moving the movable platen 58, and an ejector motor for moving an eject pin 66 incorporated in the movable platen 58 back and forth. 67, the movable platen 5 according to the thickness of the molds 55 and 56.
8 and a plurality of drive motors (servo motors) such as a mold thickness corresponding motor 68 for moving the toggle link 59.

A plurality of driving motors 62 to 65, 67, 6
8 are individually driven and controlled. For example, when each of the driving motors is a three-phase motor, as shown in FIG. 6, each of the driving motors 62 to 65, 67, and 68 is provided with a servo controller 71 via a three-phase inverter 70. Connected. Each drive motor is provided with an encoder 72 for detecting its rotation and a current sensor 73 for detecting the magnitude of the drive current supplied from the three-phase inverter 70. The detection signal from the sensor 73 is fed back to the servo controller 71.

The servo controller 71 includes an encoder 72 and a current sensor 7 under the control of a host controller (not shown).
A control signal is output to the three-phase inverter 70 based on the detection signal fed back from 3. The three-phase inverter 70 generates U, V, and W three-phase signals (drive currents) according to a control signal from the servo controller 71,
Supply to three-phase motor. Thus, the three-phase motor rotates by the designated rotation amount at the timing designated by the host controller.

As described above, in the electric injection molding machine,
Under the control of the host controller, each of the motors 42 to 47 is independently controlled by a corresponding servo controller to perform injection molding.

[0007]

In a conventional electric injection molding machine or hybrid molding machine, one inverter is connected to each drive motor, and one servo controller is connected to the inverter. Therefore, if the inverter fails and cannot be controlled by the servo controller, the motor may run away. If such a runaway occurs in, for example, a mold opening / closing motor, the mold held by the movable platen collides with the mold held by the fixed platen, and these molds are damaged.

As described above, the conventional motor control device for an injection molding machine has a problem that when an inverter breaks down and the motor runs away, there is no means for stopping the motor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a motor control device for an injection molding machine that can quickly stop the rotation of a motor even when the motor breaks down due to a failure of an inverter.

Japanese Patent Application Laid-Open No. 2000-41392 discloses a brushless DC motor in which two three-phase windings are connected to inverter circuits, respectively. However, the present invention intends to rotate the motor even when a failure occurs in the inverter circuit or the like, and the above publication does not disclose or suggest stopping the runaway motor. It has not been.

[0011]

According to the present invention, there is provided a motor control device for an injection molding machine for driving and controlling a motor used in an injection molding machine, comprising: an AC motor having a plurality of three-phase windings; A plurality of threes respectively connected to a plurality of three-phase windings
And a plurality of servo controllers respectively connected to the plurality of three-phase inverters.
Each of the phase inverters has a first self-diagnosis unit, and outputs a first abnormality signal to the servo controller connected to the first self-diagnosis unit when the first self-diagnosis unit detects an abnormality. Wherein the servo controller having received the first abnormal signal transfers the first abnormal signal to another servo controller, whereby a motor control device for an injection molding machine is obtained. .

In this motor control device for an injection molding machine, each of the plurality of servo controllers has a second self-diagnosis means. A second abnormal signal may be output to the servo controller.

Here, the other servo controller receiving the transfer of the first abnormal signal or the second abnormal signal,
The three-phase inverter connected to the servo controller is controlled to stop the AC motor.

In order to enable servo control, the motor control device for an injection molding machine includes an encoder for detecting the rotation of the AC motor and a drive current supplied to each of the plurality of three-phase windings. A plurality of sets of current sensors for detecting, wherein the plurality of servo controllers output drive from the set of current sensors for detecting a drive current supplied to the three-phase winding corresponding to each servo controller; and the encoder The three-phase inverters corresponding to the respective servo controllers are controlled based on the output from the servo controller.

Alternatively, the servo controller includes an encoder for detecting rotation of the AC motor, and a plurality of sets of current sensors for respectively detecting drive currents supplied to the plurality of three-phase windings, respectively. One is connected to the encoder and the plurality of sets of current sensors as a master controller, the other servo controller is connected to the master controller as a slave controller, and the master controller is connected to the three-phase controller corresponding to the master controller. Based on the output from the set of current sensors that detect the drive current supplied to the windings and the output from the encoder, control the three-phase inverter corresponding to the master controller, and Supplied to the corresponding three-phase winding An output from the set of current sensors for detecting the driving current, based on an output from the encoder to generate a slave control signal for controlling the three-phase inverter for each slave controller,
Each slave controller controls the three-phase inverter corresponding to the slave controller based on the slave control signal from the master controller.

As the AC motor, a three-phase double-winding AC motor or a six-phase winding AC motor can be used.

Further, according to the present invention, when a host controller is connected to at least one of the plurality of servo controllers, the host controller includes:
Upon receiving the first abnormal signal or the second abnormal signal from the connected servo controller, the molding operation is stopped immediately or the molding operation is stopped immediately after the currently executed process is completed. be able to.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. A motor control device for an injection molding machine in FIG. 1 includes a three-phase double-winding motor 11 having two three-phase windings, and two three-phase winding motors 11.
First and second 3 for respectively supplying a drive current to the phase winding
A phase inverter 12, 13, first and second servo controllers 14, 15 connected to the first and second inverters 12, 13, respectively, and an encoder 16 attached to the motor 11 and detecting its rotation. , A first and a second for detecting a drive current supplied to each three-phase winding, respectively.
Current sensors 17 and 18.

The three-phase double-winding motor 11
Two U, V, and W phase windings (U1, V
1, W1 and U2, V2, W2), and these are stacked and wound. Assuming that a normal three-phase winding is represented as shown in FIG.
become that way.

First and second three-phase inverters 12 and 13
Have the same configuration, and are each configured using a plurality of power transistors and diodes, as shown in FIG. In addition, these three-phase inverters 12, 13
Have self-diagnosis circuits (not shown) for performing self-checks (first self-diagnosis means in the claims). Each of the three-phase inverters 12 and 13 has a capability of supplying at least half of the drive current required to obtain the maximum output required for the three-phase double winding motor 11.

The first and second servo controllers 14,
Reference numeral 15 has the same configuration (operates with the same software) and has a control capability corresponding to a motor having a maximum output that is half of the maximum output required for the three-phase double winding motor 11. These first and second servo controllers 14, 1
Each of the circuits 5 has a self-diagnosis circuit (second self-diagnosis means in the claims). In addition, these servo controllers 14 and 15 can both switch between master and slave. In this case, the first servo controller 14 is set to be the master, and the second servo controller 15 is set to be the slave. The first servo controller 14 set as the master is connected to a host controller (not shown). Further, the second servo controller 15 set as the slave is connected to the first servo controller 14 set as the master.

The encoder 16 is a three-phase double winding motor 1
One rotation is detected, a predetermined number of pulses are generated for each rotation, and output to the first and second servo controllers 14 and 15. First and second servo controllers 14 and 15
Is the rotation speed of the three-phase double winding motor 11 based on the number of pulses input per unit time, and 3 based on the total number of pulses.
The rotation amount of the phase double winding motor 11 can be obtained.

The first and second current sensors 17, 18 are:
Drive currents flowing through the windings U1 and V1 and the windings U2 and V2 are detected, and the detected values are output to the first and second servo controllers 14 and 15, respectively. The first and second servo controllers 14 and 15 determine a value of 3 based on the detected value and the rotation speed and rotation amount of the three-phase double winding motor.
Control the phase inverter.

Next, the operation of the motor control device for an injection molding machine will be described.

First, the first servo controller 14
An operation command is received from a host controller (not shown). Then, when the command generates a large torque, the first servo controller 14 outputs a necessary control command to the second servo controller 15.
In addition, the first servo controller 14
The synchronization signal is supplied to the servo controller 15.

Next, the first servo controller 14
A control signal is output to first three-phase inverter 12 in accordance with an operation command from a higher-level device. Similarly, the second servo controller 15 outputs a control signal to the second three-phase inverter 13 at a timing synchronized with the synchronization signal according to a control command from the first servo controller 14.

First and second three-phase inverters 12 and 13
Are the first and second servo controllers 14,
A drive current is generated in accordance with the control signal from 15 and supplied to the three-phase double-winding motor 11. Thereby, the three-phase double winding motor 11 rotates.

The encoder 16 is a three-phase double winding motor 1
One rotation is detected, and a detection pulse is output to the first and second servo controllers 14 and 15. Further, the first and second current sensors 17 and 18 are connected to the windings U1 and V1, respectively.
1 and drive currents flowing through the windings U2 and V2, respectively, and detect the detected values with the first and second servo controllers 1 and 2.
Output to 4,15.

The first servo controller 14 changes a control signal to the first three-phase inverter 12 based on a detection value from the first current sensor 17 and a detection pulse from the encoder 16. Similarly, the second servo controller 15 outputs a detection value from the second current sensor 18 and
The control signal to the second three-phase inverter 13 is changed based on the detection pulse from the encoder 16. As a result, the drive current supplied from the first and second three-phase inverters 12 and 13 to the three-phase double winding motor 11 changes,
The rotation torque, speed, and the like of the phase double winding motor 11 are controlled.

As described above, this control device can generate a large torque in the three-phase double-winding motor 11 without using a special inverter or controller for a large output motor.

When the operation command received from the host controller by the first servo controller 14 is to generate a small torque, the servo controller 14 does not output a control command to the second servo controller 15. . Then, the first servo controller 14 alone controls the rotation of the three-phase double-winding motor 11. That is,
The first servo controller 14 outputs a control signal to the first three-phase inverter 12 according to an operation command from a higher-level device, and the first three-phase inverter 12 outputs a drive current to the three-phase two-phase inverter 2 according to the control signal. It is supplied to the heavy winding motor 11.
Then, the first servo controller 14 changes a control signal to the first three-phase inverter 12 based on a detection value from the first current sensor 17 and a detection pulse from the encoder 16.

As described above, in this control device, the three-phase two
The control is performed according to the torque to be generated in the heavy winding motor 11, but in any case, the three-phase inverters 12, 13 or the servo controller 14,
When the 15 self-diagnosis circuits detect an abnormality, the operation is performed as follows.

When the self-diagnosis circuit of the three-phase inverter 12 (or 13) detects an abnormality,
If the drive current supplied to the phase double winding motor 11 cannot be controlled, an abnormal signal is output from the self-diagnosis circuit that has detected the abnormality to the servo controller 14 (or 15). The servo controller 14 (or 1) receiving the abnormal signal output from the three-phase inverter 12 (or 13)
5) outputs the abnormal signal to the servo controller 15 (or 14). Servo controller 14 (or 1
5) Servo controller 15 that has received an abnormal signal from
(Or 14) outputs a control signal to the three-phase inverter 13 (or 12) to stop the rotation of the three-phase double winding motor 11. Three-phase inverter 13 (or 1
2) The drive current supplied to stop the rotation of the three-phase double-winding motor 11 is changed based on a control signal from the servo controller 15 (or 14).

The servo controller 14 (or 1)
If the self-diagnosis circuit 5) detects an abnormality and the abnormality is such that the rotation of the three-phase double-winding motor 11 is continued, the servo controller 15
An abnormal signal is output for (or 14). The servo controller 15 (or 14) that has received the abnormal signal
As described above, a control signal for stopping the three-phase double winding motor 11 is output to the three-phase inverter 13 (or 12). Then, the three-phase inverter 13 (or 1
2) stopping the rotation of the three-phase double winding motor 11 based on a control signal from the servo controller 15 (or 14).

As described above, according to the control device of the present invention,
If an abnormality occurs in the three-phase inverter or the servo controller, the occurrence of the abnormality is determined by the operation of the normally operating 3
By notifying the normally operating servo controller connected to the three-phase inverter,
The heavy winding motor can be stopped.

In the electric injection molding machine, a plurality of motors cooperate to perform a molding operation (injection step, pressure-holding step, cooling step,
Weighing process). Therefore, when an abnormality occurs in any one of the motors and the control circuit (the inverter or the servo controller), it is necessary to stop the operation of the other motors. Therefore, when the servo controller 14 set as the master receives an abnormal signal from the three-phase inverter 12, or when the self-diagnosis circuit detects an abnormality, or when an abnormal signal is received from the servo controller 15, Outputs (transfers) an abnormal signal to the host controller. Upon receiving the abnormality signal, the host controller immediately controls the other motors so as to stop the molding operation immediately or to stop the molding operation immediately after completing the process currently being executed (see FIG. (Not shown). In this way, the electric injection molding machine can immediately stop the molding operation when an abnormality occurs in any of the motors.

Next, a second embodiment of the present invention will be described with reference to FIG. Here, only differences from the first embodiment will be described.

The motor control device for the injection molding machine shown in FIG.
It has a six-phase motor 31 instead of the phase double winding motor 11. The windings of the six-phase motor 31 are as shown in FIG. Also, the encoder 16 is connected only to the first servo controller 32 and the second servo controller 3
3 is not connected. Furthermore, the first and second current sensors 17 and 18 are both connected to the first servo controller 32.

The first and second servo controllers 32,
33 has the same configuration as in the first embodiment, and can switch between master and slave. Here, the first servo controller 32 is set as a master and the second servo controller is set as a slave, and the first servo controller 32 is connected to a host device (not shown). Then, under the control of the host device, the first servo controller 32 performs a first three-phase operation based on the detection values from the first and second current sensors 17 and 18 and the detection pulse from the encoder 16. A control signal to be output to the inverter 12,
A control command to be output to the second servo controller 33 is generated. Further, the second servo controller 33 controls the three-phase inverter 13 based only on a control command from the first servo controller 32.

Also in this embodiment, if an abnormality occurs in the three-phase inverter 12, the servo controller 3
An abnormal signal is transmitted from 2 to the servo controller 33. When an abnormality occurs in the three-phase inverter 13, an abnormality signal is transmitted to the servo controller 32.
As a result, when an abnormality occurs in one of the three-phase inverters 12 and 13, the rotation of the six-phase motor 31 can be stopped immediately. Also, the servo controller 33
When an abnormality occurs, the abnormality signal is transmitted to the servo controller 32, and the rotation of the six-phase motor 31 can be stopped.

When an abnormality occurs in the servo controller 32, if information necessary for control is supplied from the servo controller 32 as a control command in the servo controller 33, the rotation of the six-phase motor 31 is performed in the same manner as described above. Can be stopped.

In any case, the servo controller 32 set as the master notifies the host controller of the occurrence of an abnormality, and the host device controls another motor that is operating normally. A control command is output to a servo controller (not shown) to immediately stop the molding operation, or to immediately stop the molding operation after completing the currently executed process.

In the first embodiment, three-phase two-phase
An example using a heavy winding is described, and in the above-described second embodiment, an example using a six-phase motor is described. However, in the first embodiment, a six-phase motor is used, and the second embodiment is used. Alternatively, a three-phase double-winding motor may be used. In any case, not only a motor having two three-phase windings but also a motor having more three-phase windings may be used.

[0045]

According to the present invention, in a motor control device for an injection molding machine, an AC motor having a plurality of three-phase windings is controlled using a combination of a plurality of three-phase inverters and a plurality of servo controllers. When an abnormality occurs in any of the three-phase inverters or the servo controller, an abnormal signal is output to the normally operating servo controller, so that the AC motor does not run away, The rotation can be stopped.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a motor control device for an injection molding machine according to a first embodiment of the present invention.

FIG. 2A is a connection diagram of windings used in a three-phase motor, and FIG. 2B is a connection diagram of windings used in a three-phase double winding motor.

FIG. 3 is a block diagram showing a motor control device for an injection molding machine according to a second embodiment of the present invention.

FIG. 4 is a connection diagram of windings used in a six-phase motor.

FIG. 5 is a diagram for explaining a configuration of a general electric injection molding machine.

FIG. 6 is a block diagram showing a motor control device of a general three-phase motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 3 phase double winding motor 12 1st 3 phase inverter 13 2nd 3 phase inverter 14 1st servo controller 15 2nd servo controller 16 Encoder 17 1st current sensor 18 2nd current sensor 31 6 Phase motor 32 first servo controller 33 second servo controller

Claims (8)

[Claims] 1. A motor control device for an injection molding machine for driving and controlling a motor used in an injection molding machine, comprising: an AC motor having a plurality of three-phase windings; A plurality of three-phase inverters, and a plurality of servo controllers respectively connected to the plurality of three-phase inverters, wherein each of the plurality of three-phase inverters has first self-diagnosis means, When the self-diagnosis means detects an abnormality, the self-diagnosis means outputs a first abnormality signal to each of the connected servo controllers. A motor control device for an injection molding machine, wherein the first abnormal signal is transmitted to a controller. Each of the plurality of servo controllers has a second self-diagnosis unit, and when the second self-diagnosis unit detects an abnormality, a second abnormality signal is sent to another servo controller. 2. The motor control device for an injection molding machine according to claim 1, wherein the motor control device outputs the value. 3. The three-phase inverter connected to the servo controller so that the another servo controller receiving the transfer of the first abnormal signal or the second abnormal signal stops the AC motor. 3. The motor control device for an injection molding machine according to claim 1, wherein: 4. A servo controller comprising: an encoder for detecting rotation of the AC motor; and a plurality of sets of current sensors for respectively detecting drive currents supplied to the plurality of three-phase windings, respectively. Are based on an output from the set of current sensors that detects a drive current supplied to the three-phase winding corresponding to each servo controller, and an output from the encoder. The motor control device for an injection molding machine according to any one of claims 1 to 3, wherein the three-phase inverter is controlled. 5. The servo controller, comprising: an encoder for detecting rotation of the AC motor; and a plurality of sets of current sensors for respectively detecting drive currents supplied to the plurality of three-phase windings. One is connected to the encoder and the plurality of sets of current sensors as a master controller, the other servo controller is connected to the master controller as a slave controller, and the master controller is connected to the three-phase controller corresponding to the master controller. Based on the output from the set of current sensors that detect the drive current supplied to the windings and the output from the encoder, control the three-phase inverter corresponding to the master controller, and Drive current supplied to the corresponding three-phase winding Based on the output from the set of current sensors that detect
A slave control signal for controlling the three-phase inverter corresponding to each slave controller is generated, and each slave controller controls the three-phase inverter corresponding to the slave controller based on the slave control signal from the master controller. The motor control device for an injection molding machine according to any one of claims 1 to 3, wherein: 6. The motor control device for an injection molding machine according to claim 1, wherein said AC motor is a three-phase double winding AC motor. 7. The motor control device for an injection molding machine according to claim 1, wherein said AC motor is a six-phase winding AC motor. 8. A host controller connected to at least one of the plurality of servo controllers, wherein the host controller receives the first abnormal signal or the second abnormal signal from the connected servo controller. The injection according to any one of claims 1 to 7, wherein upon receiving an abnormal signal, the molding operation is stopped immediately or the molding operation is stopped immediately after the currently executing process is completed. Motor control device for molding machines.