CN106533270B - Motor control device - Google Patents
Motor control device Download PDFInfo
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- CN106533270B CN106533270B CN201610772710.5A CN201610772710A CN106533270B CN 106533270 B CN106533270 B CN 106533270B CN 201610772710 A CN201610772710 A CN 201610772710A CN 106533270 B CN106533270 B CN 106533270B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P5/00—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors
- H02P5/46—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors for speed regulation of two or more dynamo-electric motors in relation to one another
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Abstract
The invention provides a motor control device which can synchronously control more than three motors and can synchronize the motors with high precision even if a torque command is saturated. When a torque command for any of the motors is saturated, the motor control device limits the rate of change in the speed of the other motor to the acceleration of the motor with the minimum acceleration.
Description
Technical Field
The present invention relates to a motor control device.
Background
In a large chip mounter and a large machine tool, by driving one movable part by two motors, it is possible to suppress the occurrence of displacement of the movable part and improve the positional accuracy. In a large-sized injection molding machine, one movable portion is driven by two motors, so that the size of the machine can be reduced.
According to the technique disclosed in Japanese patent laid-open publication No. 61-237615, ball screws are provided on both sides of an injection screw. The injection screw is driven by two motors. The two motors are controlled synchronously. A motor control device for driving a motor limits a torque command by a torque limiter according to a restriction of a current that the motor control device can output at maximum. However, when there is a difference between the torque constants of the two motors, the torque command of the shaft having a small torque constant is first limited to be saturated. When the torque command is saturated, a larger torque cannot be output. Therefore, the torque of the shaft having a large torque constant becomes large as compared with the torque of the shaft. As a result, the connecting portions of the two ball screws are no longer at right angles to the ball screws. Therefore, the ball screw may be damaged by receiving an excessive force.
Japanese patent laying-open No. 2015-120302 discloses a technique for improving synchronism between motors when torque is limited. According to the technique of the above-mentioned document, in order to protect the driven member, when the torque is lower than a value determined by the restriction of the maximum output current of the motor control device, the torque limit value is corrected in order to maintain good synchronism between the motors. Specifically, the torque limit value is corrected using a correction value obtained by a proportional-integral operation with respect to a position difference or a speed difference (synchronization error) between the two axes. Thereby, the torque limit value of each shaft is corrected so as to reduce the synchronization error. As a result, the synchronism between the two axes can be maintained well.
It is considered that the method described in the above-mentioned Japanese patent laid-open publication No. 2015-120302 is applied to a structure of three axes or more. In this document, only the torque limit value of the driven shaft is corrected. In other words, it is not considered to apply correction to both the driving shaft and the driven shaft. If friction occurs in the driven shaft when the torque limit value reaches the maximum output value of the motor control device, for example, the torque limit value of the driven shaft cannot be further increased, and therefore, a positional deviation between the shafts occurs. Further, according to the technique of this document, the torque limit value is corrected based on the position difference or the speed difference. Therefore, it is difficult to instantaneously detect the influence of the torque difference between the two shafts. Therefore, it becomes difficult to adjust the proportional-integral operation parameter. As a result, it may be difficult to sufficiently reduce the synchronization error.
Disclosure of Invention
The present invention has been made in view of the above problems. An object of the present invention is to provide the following motor control device. The motor control device can synchronously control more than three motors. Further, the motor control device can synchronize the motors with high accuracy even when the torque command is saturated.
When a torque command for any motor is saturated, a motor control device according to an aspect of the present invention limits a rate of change in speed of another motor to an acceleration of the motor with the minimum acceleration.
According to the motor control device, even if there is a difference between the torque constant of each motor and the friction of the plant system, the acceleration of each motor can be synchronized with high accuracy when the torque command is saturated. The motor control device may be used when three or more motors are synchronously controlled.
For example, the motor control device includes a motor control unit that controls each of the plurality of motors so as to synchronize the plurality of motors with each other, and the motor control unit includes a torque command saturation detector that detects that a torque command for the motor is saturated due to reaching an applied limit value, and when the torque command for any one of the plurality of motors is saturated, the motor control unit limits a rate of change of speed of the other motor to a minimum acceleration among accelerations of the plurality of motors.
Drawings
Fig. 1 is a control block diagram showing the configuration of a motor control device according to embodiment 1.
Fig. 2 is a control block diagram showing the configuration of a motor control device according to embodiment 2.
Fig. 3 is a control block diagram showing the configuration of a motor control device according to embodiment 3.
Fig. 4 is a control block diagram showing the configuration of a motor control device according to embodiment 4.
Fig. 5 is a control block diagram showing the configuration of a motor control device according to embodiment 5.
Fig. 6 is a control block diagram showing the configuration of a motor control device according to embodiment 6.
Description of the reference numerals
110 position controller
120 first rate limiter
130 speed controller
140 torque limiter
150 first torque command saturation detector
160 torque controller
170 average position calculator
210 position compensator
220 second speed rate limiter
230 speed controller
240 torque limiter
250 second torque command saturation detector
260 torque controller
270 position controller
1000 motor control device
Detailed Description
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It may be evident, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
(embodiment mode 1)
Fig. 1 is a control block diagram showing a configuration of a motor control device 1000 according to a first embodiment (embodiment 1) of the present invention. The motor control device 1000 of embodiment 1 drive-controls the first motor 410 and the second motor 430 of the drive apparatus 500 in synchronization with each other. In fig. 1, for the sake of easy observation, a control system for controlling the first motor 410 and a control system for controlling the second motor 430 are enclosed by dashed boxes, respectively. These control systems constitute a motor control unit. The operation of each component (controller or the like) provided in the motor control device 1000 will be described below.
The first rotational position sensor 420 detects a rotational position (first position) of the first motor 410. The second rotational position sensor 440 detects the rotational position (second position) of the second motor 430. An encoder may be mentioned as an example of such sensors. However, these sensors are not limited to encoders.
The motor controller 1000 obtains the speed (first speed) V1 of the first motor 410 by differentiating the first position with time, and obtains the acceleration (first acceleration) a1 of the first motor 410 by differentiating the first position with time twice. These differentiation operations may be implemented, for example, by suitable differentiators. The differentiator for determining the first speed V1 may be disposed, for example, between the first rotational position sensor 420 and the speed controller 130 in fig. 1. The differentiator for determining the first acceleration a1 may be implemented by, for example, two differentiators located on the downstream side of the first rotational position sensor 420 in fig. 1. Other differentiation operations described below can also be performed by an appropriate differentiator.
The first speed change rate limiter 120 limits the speed change rate of the first motor 410 by limiting the first speed command. That is, when the torque command (second torque command) for the other motor (here, the second motor 430) is saturated, the first speed change rate limiter 120 suppresses the rate of change of the first speed command. Thus, the first rate of change limiter 120 synchronizes the first motor 410 with the second motor 430. The details will be described later.
The speed controller 130 calculates a first torque command for the first motor 410 based on a difference between the first speed command, the rate of change of which is suppressed by the first speed change rate limiter 120, and the first speed V1. The first torque command is configured (calculated) so as to compensate for a difference between the first speed command and the first speed V1. The difference between the first speed command and the first speed V1 can be calculated, for example, by a subtractor disposed between the first speed change rate limiter 120 and the speed controller 130 in fig. 1.
When the first torque command from the speed controller 130 reaches or exceeds the maximum torque limit value, the torque limiter 140 limits the first torque command from the torque limiter 140 so that the first torque command does not exceed the maximum torque limit value. That is, the torque limiter 140 performs torque limitation for the first torque command. The maximum torque limit value may be determined in advance in accordance with the maximum output current of the motor control device 1000, for example. The same applies to the torque limit values of other motors described below.
When the first torque command from the speed controller 130 is smaller than the maximum torque limit value, the torque limiter 140 may output the first torque command from the speed controller 130 as it is. The torque controller 160 may control the torque of the first motor 410 according to the first torque command, thereby driving the first motor 410.
When the first torque command is equal to or greater than the maximum torque limit value, the first torque command saturation detector 150 determines that the first torque command is saturated. The first torque command saturation detector 150 notifies the speed change rate limiter of the other motor (here, the second speed change rate limiter 220 described later) that the first torque command is saturated. The reason why the first torque command is saturated is that the first torque command is limited by the torque limiter 140 to a value not higher than the maximum torque limit value. The same applies to saturation of the torque commands of the other motors.
The torque controller 160 controls the torque of the first motor 410 in accordance with the first torque command after the torque limitation, thereby driving the first motor 410.
The motor controller 1000 obtains the speed (second speed) V2 of the second motor 430 by differentiating the second position with time, and obtains the acceleration (second acceleration) a2 of the second motor 430 by differentiating the second position with time twice. The differentiator for determining the second speed V2 may be arranged between the second rotational position sensor 440 and the speed controller 230 in fig. 1, for example. The differentiator for determining the second acceleration a2 may be implemented by, for example, two differentiators located on the downstream side of the second rotational position sensor 440 in fig. 1.
The position compensator 210 calculates a compensation value (compensation command) based on the difference between the first position and the second position. The compensation value is configured (calculated) so as to compensate for a difference between a position command (first position) and a second position for the second motor 430. That is, the position compensator 210 calculates a compensation command for compensating the position of the second motor 430 based on the difference between the position of the first motor 410 and the position of the second motor 430. The difference between the first position and the second position can be calculated, for example, by a subtractor disposed between the second rotational position sensor 440 and the position compensator 210 in fig. 1.
The second speed change rate limiter 220 limits the speed change rate of the second motor 430 by limiting the second speed command. That is, when the torque command (first torque command) for the other motor (here, the first motor 410) is saturated, the second speed change rate limiter 220 suppresses the change rate of the second speed command. Thus, the second speed rate limiter 220 synchronizes the second motor 430 with the first motor 410. The details will be described later.
The speed controller 230 calculates a second torque command for the second electric machine 430 based on the difference between the speed command, the rate of change of which is suppressed by the second speed rate limiter 220, and the second speed V2. The second torque command is configured (calculated) so as to compensate for a difference between the second speed command and the second speed V2. The difference between the second speed command and the second speed V2 can be calculated, for example, by a subtractor disposed between the second speed change rate limiter 220 and the speed controller 230 in fig. 1.
When the second torque command from the speed controller 230 reaches the maximum torque limit value or more, the torque limiter 240 limits the second torque command from the torque limiter 240 so that the second torque command does not exceed the maximum torque limit value. That is, the torque limiter 240 performs torque limitation for the second torque command.
When the second torque command is equal to or greater than the maximum torque limit value, the second torque command saturation detector 250 determines that the second torque command is saturated. The second torque command saturation detector 250 notifies the speed change rate limiter of the other motor (here, the first speed change rate limiter 120) that the second torque command is saturated. The torque controller 260 controls the torque of the second motor 430 in accordance with the second torque command after the torque limitation, thereby driving the second motor 430.
When the second torque command from the speed controller 230 is smaller than the maximum torque limit value, the torque limiter 240 may output the second torque command from the speed controller 230 as it is. The torque controller 260 may control the torque of the second motor 430 according to the second torque command, thereby driving the second motor 430.
When it is detected that the second torque command is saturated, the first speed change rate limiter 120 sets the rate of change of the first speed command to the second acceleration a 2. Thus, the first speed change rate limiter 120 suppresses (limits) the rate of change of the first speed command so as to avoid the rate of change of the first speed command from becoming equal to or greater than the second acceleration a 2. When the second torque command is not saturated, the first speed change rate limiter 120 outputs the first speed command output from the position controller 110 as it is without performing the process of suppressing (limiting) the rate of change of the first speed command. That is, the first speed change rate limiter 120 limits the speed change rate of the first motor 410 by limiting the first speed command (e.g., limiting the rate of change of the first speed command).
When it is detected that the first torque command is saturated, the second speed change rate limiter 220 sets the rate of change of the second speed command to the first acceleration a 1. Thus, the second speed change rate limiter 220 suppresses (limits) the change rate of the second speed command so as to avoid the change rate of the second speed command from reaching the first acceleration a1 or more. When the first torque command is not saturated, the second speed change rate limiter 220 outputs the second speed command as it is without performing a process of suppressing (limiting) the change rate of the second speed command. That is, the second speed change rate limiter 220 limits the speed change rate of the second motor 430 by limiting the second speed command (e.g., limiting the rate of change of the second speed command).
By the above-described operations of the first speed change rate limiter 120 and the second speed change rate limiter 220, when the torque command for any one of the motors is saturated, the rate of change of the speed command for the other motor is limited to the acceleration of the motor whose torque command is saturated. Therefore, when the torque command is saturated, even if there is a deviation in the friction of the motor shafts and/or the torque constant of the motors, the accelerations of the motors can be synchronized with each other. The acceleration of the motor is obtained by differentiating the rotation position of the motor twice with time. Therefore, in the present embodiment, the positional shift between the motors can be suppressed from the viewpoint of acceleration.
In addition, the first speed change rate limiter 120 may limit the speed change rate of the first motor 410 to the minimum acceleration among the accelerations of the motors when the torque command for the second motor 430 is saturated. Also, the second speed change rate limiter 220 may limit the speed change rate of the second motor 430 to a minimum acceleration among accelerations of the motors when the torque command for the first motor 410 is saturated.
As described above, the motor control device 1000 includes the motor control unit that controls the motors so that the motors are synchronized with each other. The motor control unit includes a torque command saturation detector that detects that a torque command for the motor is saturated when the torque command reaches an applied limit value. Further, when the torque command for any one of the motors is saturated, the motor control unit may limit the rate of change in the speed of the other motor to the minimum acceleration among the accelerations of the plurality of motors.
(embodiment mode 2)
Fig. 2 is a control block diagram showing the configuration of a motor control device 1000 according to a second embodiment (embodiment 2) of the present invention. The motor control device 1000 of embodiment 2 drive-controls the first motor 410, the second motor 430, and the third motor 450 of the drive apparatus 500 in synchronization with each other. The third rotational position sensor 460 detects the rotational position (third position) of the third motor 450. Except for the difference in controlling three motors, the motor control device 1000 of embodiment 2 has substantially the same configuration as that of embodiment 1. Hereinafter, differences between embodiment 1 and embodiment 2 will be mainly described.
When the torque command (i.e., the second torque command or the third torque command) for the other motor (here, the second motor 430 or the third motor 450) is saturated, the first speed change rate limiter 120 suppresses the rate of change of the first speed command. Thus, the first rate limiter 120 synchronizes the first motor 410 with the other motors. When the first torque command is equal to or greater than the maximum torque limit value, the first torque command saturation detector 150 notifies the speed change rate limiters (the second speed change rate limiter 220 and a third speed change rate limiter 320, which will be described later) of the other motors that the first torque command is saturated. The other configuration of the control system for controlling the first motor 410 is the same as that of embodiment 1.
The second speed change rate limiter 220 suppresses the rate of change of the second speed command when the torque command (i.e., the first torque command or the third torque command) for the other motor (here, the first motor 410 or the third motor 450) is saturated. Thus, the second speed rate limiter 220 synchronizes the second motor 430 with the other motors. When the second torque command is equal to or greater than the maximum torque limit value, the second torque command saturation detector 250 notifies the speed change rate limiters (the first speed change rate limiter 120 and a third speed change rate limiter 320, which will be described later) of the other motors that the second torque command is saturated. The other configuration of the control system for controlling the second motor 430 is the same as that of embodiment 1.
The position compensator 310 calculates a compensation value according to a difference between the first position and the third position. The compensation value is configured (calculated) so as to compensate for a difference between a position command (first position) for the third motor 450 and a third position. The difference between the first position and the third position may be calculated by, for example, a subtractor disposed between the third rotational position sensor 460 and the position compensator 310 in fig. 1.
The third speed change rate limiter 320 limits the speed change rate of the third motor 450 by limiting the third speed command. That is, when the torque command (i.e., the first torque command or the second torque command) for the other motor (here, the first motor 410 or the second motor 430) is saturated, the third speed change rate limiter 320 suppresses the rate of change of the third speed command. Thus, the third speed rate limiter 320 synchronizes the third motor 450 with the other motors.
The speed controller 330 calculates a third torque command for the third motor 450 based on the difference between the speed command, the rate of change of which is suppressed by the third speed rate limiter 320, and the third speed V3. The third torque command is configured (calculated) so as to compensate for a difference between the third speed command and the third speed V3. The difference between the third speed command and the third speed V3 can be calculated, for example, by a subtractor disposed between the third speed change rate limiter 320 and the speed controller 330 in fig. 1.
When the third torque command from the speed controller 330 reaches the maximum torque limit value or more, the torque limiter 340 limits the third torque command from the torque limiter 340 so that the third torque command does not exceed the maximum torque limit value. That is, the torque limiter 340 performs torque limitation for the third torque command.
When the third torque command reaches the maximum torque limit value or more, the third torque command saturation detector 350 determines that the third torque command is saturated. The third torque command saturation detector 350 notifies the speed change rate limiters (the first speed change rate limiter 120 and the second speed change rate limiter 220) of the other motors that the third torque command is saturated. The torque controller 360 controls the torque of the third motor 450 in accordance with the torque-limited third torque command, thereby driving the third motor 450.
When the third torque command from the speed controller 330 is smaller than the maximum torque limit value, the torque limiter 340 may output the third torque command from the speed controller 330 as it is. The torque controller 360 may control the torque of the third motor 450 according to the third torque command, thereby driving the third motor 450.
The other components (such as differentiators) of the control system of the third motor 450 function in the same manner as the corresponding components of the control system of the second motor 430.
When the torque command for any other motor is saturated, the speed change rate limiter (the first speed change rate limiter 120, the second speed change rate limiter 220, and the third speed change rate limiter 320) of each control system limits the rate of change of the speed command of the control system to which the speed limiter belongs to the minimum acceleration among the accelerations of the other motors. When the torque command for the other motor is not saturated, the process of limiting the rate of change of the speed command is not performed.
For example, when the second torque command or the third torque command is saturated, the first speed change rate limiter 120 limits the change rate of the first speed command to the smaller one of the second acceleration a2 and the third acceleration A3. Thereby, the rate of change of the first speed command is controlled not to exceed the minimum motor acceleration.
By the above-described operation of each speed change rate limiter, when the torque command of a certain control system is saturated, the rate of change of the speed command of the control system is limited to the minimum acceleration of the other control system. Therefore, when the torque command for any of the motors is saturated, the accelerations of the motors are controlled to be synchronized with each other. Thus, when the torque command for any motor is saturated, the accelerations of the motors can be synchronized with each other even if there is a difference in friction of the motor shafts and/or a difference in torque constant of the motors. As a result, positional displacement between the motors can be suppressed.
(embodiment mode 3)
Fig. 3 is a control block diagram showing the configuration of a motor control device 1000 according to a third embodiment (embodiment 3) of the present invention. The motor control device 1000 according to embodiment 3 includes the average position calculator 170, but does not include the position compensator 210, in addition to the configuration described in embodiment 1. The other structure is substantially the same as embodiment 1. Therefore, the following mainly explains the difference between embodiment 1 and embodiment 3.
The average position calculator 170 calculates an average (average position) of the first position and the second position. The position controller 110 calculates a first speed command from a difference between the average position and the position command. The difference between the average position and the position command may be calculated, for example, by a subtractor located between the position controller 110 and the average position calculator 170 in fig. 3. The first speed command is configured (calculated) so as to compensate for a difference between the position command and the average position. That is, the first speed command is controlled so that the average position approaches the position command. The other configuration of the control system of the first motor 410 is the same as that of embodiment 1.
Unlike embodiment 1, the second speed change rate limiter 220 uses the first speed command as a speed command for the second motor 430 (i.e., a second speed command). That is, the position controller 110 according to embodiment 3 calculates a first speed command for the first motor 410 and a second speed command for the second motor 430 based on a difference between the position command for the first motor 410 and the average position. The second speed change rate limiter 220 limits the speed change rate of the second motor 430 by limiting the second speed command. The control of the rotational position of the second motor 430 is implemented by compensating for the difference between the average position and the position command. The other configuration of the control system of the second motor 430 is the same as that of embodiment 1.
In embodiment 3, as in embodiment 1, when a torque command of an arbitrary motor is saturated, the rate of change of the speed command of another motor is limited to the acceleration of the motor whose torque command is saturated. Thereby, the accelerations of the motors can be synchronized with each other.
(embodiment mode 4)
Fig. 4 is a control block diagram showing the configuration of a motor control device 1000 according to a fourth embodiment (embodiment 4) of the present invention. The motor control device 1000 according to embodiment 4 includes a position controller (second position controller) 270 instead of the position compensator 210 described in embodiment 1. The other structure is substantially the same as embodiment 1. Therefore, differences between embodiment 1 and embodiment 4 will be mainly described below.
In embodiment 4, the position command for the first motor 410 is also used as the position command for the second motor 430. That is, each motor is controlled based on a position command (common position command) common to the motors. Specifically, the position controller 110 calculates a first speed command for the first motor 410 based on a difference between a common position command common to the motors and the position of the first motor. The position controller 270 calculates the second speed command based on the difference between the common position command and the second position. The second speed command is configured (calculated) so as to compensate for a difference between the common position command and the second position. The difference between the common position command and the second position can be calculated, for example, by a subtractor disposed upstream of the position controller 270 (between the second rotational position sensor 440 and the position controller 270) in fig. 4. The second speed change rate limiter 220 receives the second speed command calculated by the position controller 270 as it is. The other structure is the same as embodiment 1.
In embodiment 4, as in embodiment 1, when the torque command of any one of the motors is saturated, the rate of change of the speed command of the other motor is limited to the acceleration of the motor whose torque command is saturated. Thereby, the accelerations of the motors can be synchronized with each other.
(embodiment 5)
Fig. 5 is a control block diagram showing the configuration of a motor control device 1000 according to a fifth embodiment (embodiment 5) of the present invention. Motor control apparatus 1000 according to embodiment 5 does not include position controller 110 and position compensator 210 in the configuration described in embodiment 1. Further, motor control device 1000 receives a speed command for first motor 410 from, for example, an external device, instead of a position command for first motor 410. The other structure is substantially the same as embodiment 1. Therefore, differences between embodiment 1 and embodiment 5 will be mainly described below.
The first speed change rate limiter 120 uses a speed command (a first speed command for the first motor) received by the motor control device 1000 instead of the first speed command in embodiment 1. The second speed change rate limiter 220 uses the first speed V1 as a second speed command for the second motor, instead of the second speed command in embodiment 1. Thereby, the speeds of the motors are controlled to be synchronized with each other. The other structure is the same as embodiment 1.
In embodiment 5, as in embodiment 1, when the torque command of any one of the motors is saturated, the rate of change of the speed command of the other motor is limited to the acceleration of the motor whose torque command is saturated. Thereby, the accelerations of the motors can be synchronized with each other.
(embodiment mode 6)
Fig. 6 is a control block diagram showing the configuration of a motor control device 1000 according to a sixth embodiment (embodiment 6) of the present invention. The motor control device 1000 according to embodiment 6 is similar to that of embodiment 5, and the configuration described in embodiment 1 does not include the position controller 110 and the position compensator 210. However, unlike embodiment 5, the second speed change rate limiter 220 of embodiment 6 uses a speed command for the first motor 410 as the second speed command instead of the first speed V1. That is, the motors are controlled based on a speed command common to the motors. The other structure is the same as embodiment 5. Embodiment 6 can also exhibit the same effects as embodiment 5.
(embodiment 7)
According to embodiments 1 to 6 described above, when the torque command for any one of the motors is saturated, the speed change rate limiter of the other motor can limit the speed change rate of the corresponding motor to the minimum acceleration among the accelerations of the motors. In order to more effectively exhibit the effect of the method, each of the speed change rate limiters may limit the speed change rate of each of the motors to the minimum acceleration among the accelerations of all the motors whose torque commands have been saturated. That is, when the torque command for any one of the motors is saturated, the motor control unit may limit the rate of change in the speed of the other motor to the minimum acceleration among the accelerations of the motors whose torque commands are saturated.
For example, in the configuration described in embodiment 2, the second torque command and the third torque command are saturated. At this time, the first speed change rate limiter 120 limits the change rate of the first speed command to the smaller of the second acceleration a2 and the third acceleration A3. Thus, the rate of change of the first speed command is controlled so as not to exceed the minimum acceleration among the accelerations of the motor in which the torque command has been saturated. When only one motor is saturated in the torque command, the rate of change in the speed of the other motor may be controlled so as not to exceed the acceleration of the motor. The same is true when there are only two motors.
(modification of the invention)
The present invention is not limited to the above-described embodiments, and various modifications are also included. For example, the above embodiments are specifically described for the purpose of facilitating understanding of the present invention. However, the above-described embodiments are not limited to having all the components (structures) described above. In addition, some components of one embodiment may be replaced with components of another embodiment. Further, the members of other embodiments may be added to one embodiment. Further, some of the components of the embodiments may be added, deleted, or replaced with other components.
Each of the above-described components (controller, limiter, compensator, detector, adder, subtractor, differentiator, and the like) may be implemented by hardware such as a circuit device that realizes the function thereof, or may be implemented by an arithmetic device such as a cpu (central Processing unit) that executes software in which the function thereof is installed.
The position controller and the position compensator described in embodiments 1 to 7 above may be constituted by a proportional controller, for example. Further, the speed controller and the position compensator may be constituted by a proportional integral controller, for example. Other suitable controllers may be used as the controller and/or compensator, as long as the difference can be suitably compensated.
In embodiments 3 to 6, three or more motors may be synchronously controlled by the same method as in embodiment 2, and the accelerations of the motors may be synchronized when any torque command is saturated. Specifically, for example, (a) each torque command saturation detector notifies the speed change rate limiter of the other control system that the torque command is saturated, and (b) each speed change rate limiter limits the rate of change of the speed command to the minimum motor acceleration when the torque command of the other motor is saturated.
In embodiments 1 to 7 described above, instead of the maximum output current of the motor control device 1000, the maximum torque limit value of the torque limiter may be determined using the maximum torque limit value based on the constraints of the plant system. For example, the maximum torque limit value of the torque limiter may be set to be equal to or less than the maximum torque limit value based on the constraints of the plant system. Alternatively, the maximum torque limit value may be externally given to the motor control device 1000 via an appropriate interface, for example. The maximum torque limit may also be calculated using other suitable means. In this case, the accelerations of the motors may be synchronized, as in embodiments 1 to 7.
The speed controller 130 may calculate the first torque command for the first motor 410 based on a difference between the speed command in which the first speed command is suppressed by the first speed change rate limiter 120 and the first speed V1. The speed controller 230 may calculate the second torque command for the second motor 430 based on a difference between the speed command in which the second speed command is suppressed by the second speed change rate limiter 220 and the second speed V2.
When the first torque command reaches above the maximum torque limit value, the torque limiter 140 may limit the first torque command not to exceed the maximum torque limit value. When the second torque command reaches the maximum torque limit value or more, the torque limiter 240 may limit the second torque command not to exceed the maximum torque limit value.
The embodiment of the present invention may be the following first to seventh motor control devices.
The first motor control device includes a motor control unit that controls each of the motors so that the plurality of motors are synchronized with each other, and the motor control unit includes a torque command saturation detector that detects that a torque command for the motor is saturated due to reaching an applied limit value, and when the torque command for any of the motors is saturated, the motor control unit synchronizes the acceleration of each of the motors by limiting a rate of change of speed of the other motor to a minimum acceleration among accelerations of each of the motors.
The second motor control device controls the first motor and the second motor as the plurality of motors on the basis of the first motor control device, and the motor control portion includes: a position controller that calculates a first speed command for the first motor based on a difference between a position command for the first motor and a position of the first motor; a position compensator that calculates a compensation command for compensating the position of the second motor based on a difference between the position of the first motor and the position of the second motor; a first speed change rate limiter that limits a speed change rate of the first motor by limiting the first speed command; a summer for calculating a second speed command for the second motor by summing the first speed command and the compensation command; and a second speed change rate limiter that limits a speed change rate of the second motor by limiting the second speed command, the first speed change rate limiter limiting the speed change rate of the first motor to a minimum acceleration among accelerations of the motors when the torque command for the second motor is saturated, and the second speed change rate limiter limiting the speed change rate of the second motor to a minimum acceleration among accelerations of the motors when the torque command for the first motor is saturated.
The third motor control device is based on the first motor control device, the motor control section controls the first motor and the second motor as the plurality of motors, and the motor control section includes: an average position calculator that calculates an average position that averages the positions of the first motor and the second motor; a position controller that calculates a first speed command for the first motor and a second speed command for the second motor based on a difference between a position command for the first motor and the average position; a first speed change rate limiter that limits a speed change rate of the first motor by limiting the first speed command; and a second speed change rate limiter that limits a speed change rate of the second motor by limiting the second speed command, the first speed change rate limiter limiting the speed change rate of the first motor to a minimum acceleration among accelerations of the motors when the torque command for the second motor is saturated, and the second speed change rate limiter limiting the speed change rate of the second motor to a minimum acceleration among accelerations of the motors when the torque command for the first motor is saturated.
A fourth motor control device on the basis of the first motor control device, the motor control section controls a first motor and a second motor as the plurality of motors, the motor control section including: a first position controller that calculates a first speed command for the first motor based on a difference between a common position command shared between the first motor and the second motor and a position of the first motor; a second position controller that calculates a second speed command for the second motor based on a difference between the common position command and a position of the second motor; a first speed change rate limiter that limits a speed change rate of the first motor by limiting the first speed command; and a second speed change rate limiter that limits a speed change rate of the second motor by limiting the second speed command, the first speed change rate limiter limiting the speed change rate of the first motor to a minimum acceleration among accelerations of the motors when the torque command for the second motor is saturated, and the second speed change rate limiter limiting the speed change rate of the second motor to a minimum acceleration among accelerations of the motors when the torque command for the first motor is saturated.
A fifth motor control device is the first motor control device, wherein the motor control section controls the first motor and the second motor as the plurality of motors, and the motor control section includes: a first speed change rate limiter that limits a speed change rate of the first motor by limiting a first speed command for the first motor; and a second speed change rate limiter that limits a speed change rate of the second motor by limiting a second speed command for the second motor, the first speed change rate limiter limiting the speed change rate of the first motor to a minimum acceleration among accelerations of the motors when the torque command for the second motor is saturated, and the second speed change rate limiter limiting the speed change rate of the second motor to a minimum acceleration among accelerations of the motors when the torque command for the first motor is saturated.
The sixth motor control device is based on the fifth motor control device, and the first speed command and the second speed command are common speed commands for the first motor and the second motor.
The seventh motor control device synchronizes the accelerations of the motors by limiting the rate of change in the speed of the other motor to the minimum acceleration among the accelerations of the motors whose torque commands are saturated, when the torque command for any one of the motors is saturated, in addition to the first motor control device.
The detailed description has been presented for purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. The detailed description is not intended to be exhaustive or to limit the subject matter described herein. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts described are disclosed as example forms of implementing the claims.
Claims (7)
1. A motor control device is characterized in that,
includes a motor control section that controls each of the motors in such a manner that the plurality of motors are synchronized with each other,
the motor control unit includes a torque command saturation detector that detects saturation of a torque command for the motor due to reaching an applied limit value,
when a torque command for any one of the motors is saturated, the motor control unit limits the rate of change in the speed of the other motor to a minimum acceleration among the accelerations of the plurality of motors.
2. The motor control apparatus according to claim 1,
the motor control section controls a first motor and a second motor as the plurality of motors,
the motor control section includes:
a position controller that calculates a first speed command for the first motor based on a difference between a position command for the first motor and a position of the first motor;
a position compensator that calculates a compensation command for compensating the position of the second motor based on a difference between the position of the first motor and the position of the second motor;
a first speed change rate limiter that limits a speed change rate of the first motor by limiting the first speed command;
a summer for calculating a second speed command for the second motor by summing the first speed command and the compensation command; and
a second speed change rate limiter that limits a speed change rate of the second motor by limiting the second speed command,
the first speed change rate limiter limits the speed change rate of the first motor to a minimum acceleration among accelerations of the respective motors when a torque command for the second motor is saturated,
the second speed change rate limiter limits the speed change rate of the second motor to a minimum acceleration among accelerations of the respective motors when a torque command for the first motor is saturated.
3. The motor control apparatus according to claim 1,
the motor control section controls a first motor and a second motor as the plurality of motors,
the motor control section includes:
an average position calculator that calculates an average position of the first motor and the position of the second motor;
a position controller that calculates a first speed command for the first motor and a second speed command for the second motor based on a difference between a position command for the first motor and the average position;
a first speed change rate limiter that limits a speed change rate of the first motor by limiting the first speed command; and
a second speed change rate limiter that limits a speed change rate of the second motor by limiting the second speed command,
the first speed change rate limiter limits the speed change rate of the first motor to a minimum acceleration among accelerations of the respective motors when a torque command for the second motor is saturated,
the second speed change rate limiter limits the speed change rate of the second motor to a minimum acceleration among accelerations of the respective motors when a torque command for the first motor is saturated.
4. The motor control apparatus according to claim 1,
the motor control section controls a first motor and a second motor as the plurality of motors,
the motor control section includes:
a first position controller that calculates a first speed command for the first motor based on a difference between a common position command shared between the first motor and the second motor and a position of the first motor;
a second position controller that calculates a second speed command for the second motor based on a difference between the common position command and a position of the second motor;
a first speed change rate limiter that limits a speed change rate of the first motor by limiting the first speed command; and
a second speed change rate limiter that limits a speed change rate of the second motor by limiting the second speed command,
the first speed change rate limiter limits the speed change rate of the first motor to a minimum acceleration among accelerations of the respective motors when a torque command for the second motor is saturated,
the second speed change rate limiter limits the speed change rate of the second motor to a minimum acceleration among accelerations of the respective motors when a torque command for the first motor is saturated.
5. The motor control apparatus according to claim 1,
the motor control section controls a first motor and a second motor as the plurality of motors,
the motor control section includes:
a first speed change rate limiter that limits a speed change rate of the first motor by limiting a first speed command for the first motor; and
a second speed change rate limiter that limits a speed change rate of the second electric machine by limiting a second speed command for the second electric machine,
the first speed change rate limiter limits the speed change rate of the first motor to a minimum acceleration among accelerations of the respective motors when a torque command for the second motor is saturated,
the second speed change rate limiter limits the speed change rate of the second motor to a minimum acceleration among accelerations of the respective motors when a torque command for the first motor is saturated.
6. The motor control device according to claim 5, wherein the first speed command and the second speed command are speed commands common to the first motor and the second motor.
7. The motor control device according to claim 1, wherein when the torque command for any one of the motors is saturated, the motor control unit limits the rate of change in the speed of the other motor to a minimum acceleration among accelerations of the motors whose torque commands are saturated.
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| JP2015177726 | 2015-09-09 | ||
| JP2015-177726 | 2015-09-09 | ||
| JP2016137524A JP6745661B2 (en) | 2015-09-09 | 2016-07-12 | Motor control device |
| JP2016-137524 | 2016-07-12 |
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| CN106533270A CN106533270A (en) | 2017-03-22 |
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| JP (1) | JP6745661B2 (en) |
| CN (1) | CN106533270B (en) |
| PH (1) | PH12016000310B1 (en) |
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| CN108712115A (en) * | 2018-05-21 | 2018-10-26 | 南京航空航天大学 | A kind of bi-motor position synchronization control strategy study design |
| CN111572218B (en) * | 2020-05-27 | 2021-03-26 | 天津丽彩数字技术有限公司 | Printer ink vehicle control method, device and system |
| JP7438097B2 (en) * | 2020-12-25 | 2024-02-26 | 三菱電機株式会社 | Drive command generation device, synchronous control system and learning device |
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| JP5120435B2 (en) * | 2010-09-30 | 2013-01-16 | ブラザー工業株式会社 | Motor control device |
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- 2016-07-12 JP JP2016137524A patent/JP6745661B2/en active Active
- 2016-08-30 CN CN201610772710.5A patent/CN106533270B/en active Active
- 2016-09-06 PH PH12016000310A patent/PH12016000310B1/en unknown
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| EP1426222A1 (en) * | 2002-11-26 | 2004-06-09 | Nissan Motor Company, Limited | Hybrid transmission control system |
| CN1529215A (en) * | 2003-09-27 | 2004-09-15 | 哈尔滨工业大学 | Motor controlling device |
| CN101330275A (en) * | 2007-06-19 | 2008-12-24 | 株式会社日立产机系统 | Induction motor drive unit, motor drive system, and elevating system |
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Also Published As
| Publication number | Publication date |
|---|---|
| PH12016000310A1 (en) | 2018-03-12 |
| TW201711824A (en) | 2017-04-01 |
| JP6745661B2 (en) | 2020-08-26 |
| PH12016000310B1 (en) | 2018-03-12 |
| CN106533270A (en) | 2017-03-22 |
| JP2017055636A (en) | 2017-03-16 |
| TWI725053B (en) | 2021-04-21 |
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