Servo DC power supply system, motor control device, and servo motor control method

Abstract

To provide a technique to prevent the oscillation of voltage in a servo DC power supply system including a motor controller that receives supply of power from a DC power supply through a power supply path.SOLUTION: A servo DC power supply system includes a DC power supply, one or more motor controllers that each control a corresponding servo motor, and a power supply path that distributes and supplies power from the DC power supply to the one or more motor controllers. The one or more motor controllers each comprise: a current control loop unit that, for a servo input end voltage input to the motor controller from the power supply path, controls a current flowing in the servo motor by using a signal on which predetermined filter processing is performed for attenuating a high frequency side of the servo input end voltage according to a frequency related to the vibration of voltage in the system; and an adjustment unit that, based on a predetermined parameter related to the vibration of voltage, adjusts a frequency band associated with the predetermined filter processing.SELECTED DRAWING: Figure 3A

Description

[Technical field]

[0001] The present invention relates to a servo DC power supply system, a motor control device, and a method for controlling a servo motor. [Background technology]

[0002] In factories, etc., systems (such as a system consisting of a robot and its control device) are used in which multiple electric motors are PWM-driven by multiple servo drivers located at distant locations. Such systems have problems such as the inability to increase the switching speed in order to reduce radiation noise from the long cable between the electric motors and the servo drivers, and the need for multiple cables to connect the electric motors and the servo drivers. The above problems can be prevented by arranging a device (hereinafter, a motor control device) in which the converter is removed from the servo driver near each electric motor and adopting a configuration in which power is supplied to multiple motor control devices from a single DC power source via a DC bus. However, in a system adopting this configuration, the LC circuit on the DC bus side and the inverter circuit side in the motor control device may interfere with each other, causing the voltage of the DC bus to oscillate (for example, see Non-Patent Document 1).

[0003] For example, Patent Document 1 discloses a technique for suppressing motor torque ripple caused by vibration of the DC bus. In this technique, the AC component of the DC bus voltage is extracted using a high-pass filter, and a correction signal obtained by multiplying the AC component by a predetermined gain is added to the voltage command in the motor control device to control the inverter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 060357 [Non-patent literature]

[0005] [Non-Patent Document 1] Masashi Yokoo, Keiichiro Kondo, "Damping control system design method for vector-controlled induction motor drive system in DC electric railway vehicles", IEEJ Transactions on Electrical Engineering, Vol. 135 No. 6 pp.622-631 (2015) Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a technique for suppressing voltage oscillations in a servo DC power supply system including a motor control device that receives power from a DC power supply via a power supply path. [Means for solving the problem]

[0007] A servo DC power supply system according to one aspect of the present invention includes a DC power source, one or more motor control devices each controlling a corresponding servo motor, and a power supply path for distributing and supplying power from the DC power source to the one or more motor control devices. Each of the one or more motor control devices includes a detection unit for detecting a servo input terminal voltage input to the motor control device from the power supply path, a current control loop unit for controlling a current flowing to the servo motor by a current control loop using a signal that has been subjected to a predetermined filtering process for attenuating a high frequency side of the servo input terminal voltage in accordance with a frequency associated with a voltage oscillation in the servo DC power supply system, and an adjustment unit for adjusting a frequency band associated with the predetermined filtering process based on a predetermined parameter associated with the voltage oscillation.

[0008] In the servo DC power supply system having the above configuration, a signal obtained by performing a predetermined filtering process on the servo input terminal voltage is used in the current control by the current control loop in the motor control device. The predetermined filtering process is a process for attenuating the high frequency side of the servo input terminal voltage, and the band on the high frequency side is a frequency band associated with the predetermined filtering process. For example, the predetermined filtering process includes an attenuation process using a low pass filter having a predetermined cutoff frequency, an averaging process that performs a function similar to that of a low pass filter in a certain frequency band, a filtering process using a band pass filter or a notch filter, etc. The frequency band associated with the predetermined filtering process is set so as to be related to the voltage oscillations in various parts of the system including the power supply path, the DC power supply, and the motor control device. As a result, even if the operating state of the servo motor is in a state in which the transfer function of the entire system from the DC power supply to the motor control device becomes unstable and oscillates in the conventional technology, it is possible to stabilize the transfer function, and thus the voltage oscillations can be suppressed. Furthermore, since the above-mentioned frequency band in the filter processing is configured to be adjusted by the adjustment unit based on predetermined parameters, the scope of application of the filter processing is not unnecessarily expanded, and torque pulsation of the servo motor and reduced responsiveness in the current control loop caused by the filter processing can be suppressed as much as possible.

[0009] Here, in the servo DC power supply system, the predetermined parameter may be at least one of the rotation speed of the corresponding servo motor and the drive current flowing through the corresponding servo motor. In this case, the adjustment unit may adjust the frequency band so that the higher the rotation speed, the lower the frequency band, and / or the higher the drive current, the lower the frequency band. When the rotation speed of the servo motor increases or the drive current increases, the power supplied through the power supply path increases, which makes it easier for voltage oscillations to occur in the power supply path. Therefore, by adopting the rotation speed or drive current of the servo motor as the predetermined parameter, the frequency band can be suitably adjusted.

[0010] Alternatively, in the servo DC power supply system, the predetermined parameter may be the servo input voltage. In this case, the adjustment unit may adjust the frequency band so that the greater the amplitude of the voltage oscillation detected in the servo DC power supply system, the lower the frequency band. This can reduce or eliminate the detected voltage oscillation. Furthermore, when the voltage oscillation does not converge after the adjustment unit adjusts the frequency band, the drive of the corresponding servo motor may be stopped. This can reliably prevent unexpected operation of the servo motor.

[0011] Here, in the servo DC power supply system described above, the filtering process may be performed by selecting one of a plurality of frequency bands, and the adjustment unit may select the one frequency band based on the predetermined parameter. Note that the filtering process may be realized by hardware such as resistors and capacitors, or may be realized by software that performs predetermined signal processing (digital processing, etc.).

[0012] The present invention can also be seen as an aspect of a motor control device that controls a servo motor in a servo DC power supply system. That is, the present invention is a motor control device that controls a servo motor with power supplied from a DC power source through a power supply line in a servo DC power supply system, comprising: a detection unit that detects a servo input terminal voltage input to the motor control device from the power supply line, a current control loop unit that controls a current flowing to the servo motor by a current control loop using a signal that has been subjected to a predetermined filtering process on the servo input terminal voltage to attenuate the high-frequency side of the servo input terminal voltage in accordance with a frequency associated with voltage oscillation in the servo DC power supply system, and an adjustment unit that adjusts a frequency band associated with the predetermined filtering process based on a predetermined parameter associated with the voltage oscillation. According to the motor control device, it is possible to effectively suppress voltage oscillations in a servo DC power supply system that supplies DC power to the motor control device.

[0013] The present invention can also be seen as a method for controlling a servo motor. That is, the present invention is a method for controlling a servo motor by a motor control device having a current control loop for controlling a drive current flowing through the servo motor and receiving power from a DC power source through a power supply line in a servo DC power supply system, the method including the steps of: detecting a servo input terminal voltage input to the motor control device from the power supply line; performing a predetermined filtering process on the servo input terminal voltage to attenuate the high frequency side of the servo input terminal voltage according to a frequency related to voltage oscillation in the servo DC power supply system; and controlling a current flowing through the servo motor by a current control loop using a signal obtained by the predetermined filtering process. This method can suitably suppress voltage oscillation in the servo DC power supply system. Furthermore, the predetermined filtering process is a process using a low-pass filter, and the cutoff frequency in the predetermined filtering process may be adjusted based on a predetermined parameter related to the voltage oscillation. As described above, the predetermined parameter in this method can be the rotation speed and driving current of the servo motor, and the voltage of the power supply line. For example, when the value of such a predetermined parameter exceeds a reference value (or, in some cases, when it becomes smaller than the reference value), this means that voltage oscillation is likely to occur. Effect of the Invention

[0014] A technique for suppressing voltage oscillations in a servo DC power supply system can be provided. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is an explanatory diagram of a configuration of a servo DC power supply system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram of the configuration of a motor control device in a servo DC power supply system. [Figure 3A] FIG. 3A is a functional block diagram of the motor control device. [Figure 3B] FIG. 3B is a detailed functional block diagram of the current control loop portion. [Figure 4] FIG. 4 is a Bode diagram of the power supply side and the motor side in a conventional DC power supply system. [Diagram 5] FIG. 5 is a diagram for explaining the difference in voltage change pattern in the power supply path between the servo DC power supply system and the conventional power supply system. [Figure 6] FIG. 6 is a first flowchart of motor control by the motor control device. [Figure 7] FIG. 7 is a second flowchart of the motor control by the motor control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] First, an overview of a servo DC power supply system according to an embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is an explanatory diagram of the configuration of the servo DC power supply system according to this embodiment, and Figure 2 is an explanatory diagram of the configuration of a motor control device 10, which is a component of the servo DC power supply system.

[0018] 1, the servo DC power supply system according to this embodiment is a system in which a DC power source 30 and a plurality of motor control devices 10 are connected via a power supply path 35. The power supply path 35 is formed so that each of the plurality of motor control devices 10 is connected to the DC power source 30 in parallel.

[0019] Here, the DC power supply 30 is a power supply that outputs a predetermined DC voltage. In Fig. 1, a device that converts three-phase AC from a three-phase AC power supply 50 into a DC voltage is shown as the DC power supply 30, but the DC power supply 30 may be a device that converts a single-phase AC into a DC voltage. The DC power supply 30 may be a rectifier circuit (e.g., a full-wave rectifier circuit) in which diodes are combined, or an AC-DC converter (e.g., a power regeneration converter) in which switching elements are used.

[0020] The motor control device 10 is a device (details will be described later) that controls a servo motor 40 (hereinafter also simply referred to as motor 40) according to commands (position commands, speed commands, etc.) from a higher-level device (not shown in FIG. 1) such as a PLC (Programmable Logic Controller). The power supply path 35 is a power supply path combining multiple power cables so that power from the DC power supply 30 can be distributed and supplied to each motor control device in the servo DC power supply system. A smoothing capacitor 15 is usually provided at the connection part of this power supply path 35 with each motor control device 10 (between the power supply terminals of each motor control device 10).

[0021] 2, the motor control device 10 includes an inverter circuit 11 and a control unit 12. The inverter circuit 11 is a circuit for converting a DC voltage (corresponding to the servo input terminal voltage of the present application) Vb input to the motor control device 10 from a power supply path 35 into a three-phase AC voltage. The inverter circuit 11 has a configuration in which a leg for a U phase, a leg for a V phase, and a leg for a W phase are connected in parallel between positive and negative bus bars, and the motor control device 10 is provided with a current sensor 28 for measuring the output current of each leg of the inverter circuit 11.

[0022] The control unit 12 is a unit that performs PWM (Pulse Width Modulation) control of the inverter circuit 11 according to commands from a higher-level device (PCL, etc.). The control unit 12 is composed of a processor (microcontroller, CPU, etc.) and its peripheral circuits, and receives signals from the current sensors 28, a signal from an encoder 41 (an absolute encoder or an incremental encoder) attached to the motor 40, and the like. The control unit 12 has a current control loop shown in Fig. 4, which will be described later, and servo control of the motor 40 is realized by receiving signals from the current sensors 28 and the encoder 41.

[0023] The servo DC power supply system according to the present embodiment and the motor control device 10 incorporated therein will be described in more detail below. The servo DC power supply system according to the present embodiment is a system in which each motor control device 10 is configured to control the current flowing through the motor 40 by a current control loop using a signal filtered by a low-pass filter configured to be adjustable in cutoff frequency in order to suppress voltage oscillations in the system including the DC power source 30, the power supply path 35, and the motor control device 10. In the servo DC power supply system according to the present embodiment, most preferably, all of the motor control devices 10 included in the servo DC power supply system are configured to perform current control using a signal filtered by a low-pass filter as described above, but some of the motor control devices 10 included in the servo DC power supply system may be configured to perform similar current control as long as the voltage oscillations can be suppressed to an acceptable range. In addition, instead of filtering by a low-pass filter, averaging processing, filtering by a band-pass filter or a notch filter, or the like that performs a function similar to that of a low-pass filter in a certain frequency band can be adopted.

[0024] The functional configuration and operation of motor control device 10 will be described below with reference to Figs. 3A and 3B, taking as an example a case where the command input from the higher-level device is a position command. Fig. 3A shows a control loop for servo-controlling motor 40 that motor control device 10 has, and Fig. 3B shows an example of the details of a current control loop section that constitutes said control loop. When motor control device 10 controls motor 40 in accordance with a position command, it is a device equipped with subtractors 21 and 23, position controller 22, speed controller 24, current control loop section 20, speed detector 29, etc. It operates as.

[0025] The subtractor 21 in this motor control device 10 is a unit that calculates a position deviation by subtracting a position detected by an encoder 41 (hereinafter, detected position) from a position command. The position controller 22 is a unit that calculates a speed command by multiplying the position deviation by a predetermined position proportional gain. The speed detector 29 is a unit that calculates a speed (hereinafter, detected speed) by differentiating the detected position. The subtractor 23 is a unit that calculates a speed deviation by subtracting the detected speed from the speed command. The speed controller 24 is a unit that calculates a current command by PI (proportional integral) calculation based on the speed deviation.

[0026] The current control loop unit 20 is a unit in which a current control loop shown in FIG. 3B is formed so as to feedback control the current flowing through the motor 40 so that a current according to a current command flows through the motor 40. As shown in the figure, the current control loop unit 20 is composed of a subtractor 25, a current controller 27, and a current sensor 28. The subtractor 25 is a unit that calculates a current deviation by subtracting a current detected by the current sensor 28 from a current command. The current controller 27 is a unit in which a current control loop shown in FIG. 3B is formed, including the inverter circuit 11. Furthermore, the current controller 27 receives a signal (hereinafter referred to as a "processed signal") that has been subjected to a predetermined low-pass filter process by a low-pass filter 26 on an input voltage Vb to the motor control device 10, and thereby controls the inverter circuit 11 so that a current according to the current command flows through the motor 40.

[0027] Here, the low-pass filter 26 is a digital filter configured so that its cut-off frequency can be adjusted. In the servo DC power supply system according to this embodiment, the cut-off wave number of the low-pass filter 26 corresponding to the current control loop unit 20 of each motor control device 10 is set to a value corresponding to a frequency related to the voltage oscillation in the system, for example, the voltage oscillation of the power supply line 35. The frequency related to the voltage oscillation may include not only the frequency of the oscillation itself, but also a frequency that causes the voltage oscillation of the power supply line 35, or a frequency in the vicinity thereof. In the current control loop unit 20, the current control is performed according to the control loop shown in FIG. 3B using the processed signal that has passed through the low-pass filter 26. Specifically, the ratio between the output signal of the subtractor 25 and the processed signal is used.

[0028] Here, consider a configuration in which the current control loop unit 20 does not use a processed signal, i.e., a conventional servo DC power supply system. Fig. 4 shows Bode plots on the power supply side and the motor side in a conventional servo DC power supply system. In such a conventional servo DC power supply system, if a transfer function obtained by integrating the transfer function on the power supply path 35 side and the transfer function on the motor control device 10 side becomes unstable, that is, if there is a frequency range in which the gain on the power supply path 35 side ("power supply side") exceeds the gain on the motor control device 10 side ("motor side") as shown in Fig. 4, the voltage on the power supply path 35 may oscillate.

[0029] Considering this, in a servo DC power supply system using a processed signal, it is preferable to adjust the cutoff frequency of the low-pass filter 26 so that it is lower than the lower limit frequency of the frequency range in which the gain on the power supply side exceeds the gain on the motor side. By using the low-pass filter 26 with the cutoff frequency adjusted in this way to control the current flowing through the motor 40 by the current control loop shown in FIG. 3B, it is possible to prevent the gain on the power supply side from exceeding the gain on the motor side at any frequency. At this time, the motor control device 10 detects the voltage Vb input to the motor control device 10 from the power supply path 35, performs low-pass filtering on the voltage Vb by the low-pass filter 26, and uses the processed signal to control the current flowing through the motor 40 by the current control loop. As a result, as shown in FIG. 5, the motor control device 10 can suitably suppress voltage oscillation even under power supply conditions (in other words, operating conditions of the motor 40) under which voltage oscillation would occur in a conventional form. It becomes possible to control it.

[0030] <First adjustment method> In this way, current control loop unit 20 performs current control using the signal processed by low-pass filter 26, which can effectively suppress voltage oscillation in power supply path 35, but at the same time, pulsation in motor 40 becomes more likely to occur. Therefore, a method of adjusting low-pass filter 26, which is a digital filter, to simultaneously suppress voltage oscillation and pulsation in motor 40 will be described with reference to the flowchart shown in Fig. 6. This adjustment method is repeatedly implemented at predetermined intervals by executing a predetermined control program in control unit 12 of motor control device 10.

[0031] First, in S101, the operating state of the motor 40 is acquired. The operating state is a parameter related to the power supplied to the motor 40, and examples thereof include the rotation speed and drive current of the motor 40. The rotation speed of the motor 40 can be calculated based on a signal from the encoder 41, and the drive current can be acquired based on a signal from the current sensor 28. Next, in S102, based on the operating state of the motor 40 acquired in S101, it is determined whether or not the operation of the motor 40 belongs to a high-speed operating region. The high-speed operating region is a range of the operating state of the motor in which the power supplied to the motor control device 10 from the DC power source 30 via the power supply path 35 becomes relatively large, and thus voltage oscillation of the power supply path 35 is likely to occur. For example, when the rotation speed of the motor 40 exceeds a predetermined rotation speed, or when the drive current of the motor 40 exceeds a predetermined drive current, it can be determined that the operating state of the motor 40 belongs to the high-speed operating region. If the determination in S102 is affirmative, the process proceeds to S103, and if the determination is negative, the process proceeds to S104.

[0032] In S103, the cutoff frequency of the low-pass filter 26 is adjusted to suppress the voltage oscillation of the power supply path 35 as described above. Specifically, the cutoff frequency is adjusted to be lower as the rotation speed of the motor 40 increases, and / or the cutoff frequency is adjusted to be lower as the drive current of the motor 40 increases. That is, the cutoff frequency is adjusted to be lower as the power supplied through the power supply path 35 increases. By such adjustment, the voltage oscillation of the power supply path 35 is suitably suppressed. Meanwhile, in S104, the low-pass filter process by the low-pass filter 26 is bypassed. That is, the operation of the low-pass filter 26, which is a digital filter, is turned off, and the signal from the subtractor 25 is directly input to the current controller 27. As an alternative to S104, when an appropriate frequency has already been set as the cutoff frequency of the low-pass filter 26 (for example, when the process of S103 has been performed previously), instead of bypassing the low-pass filter process, the low-pass filter process by the low-pass filter 26 may be performed.

[0033] 6, the suppression of voltage oscillation by low-pass filter 26 is substantially limited to when the operating state of motor 40 belongs to the high-speed operating region. Therefore, it is possible to suitably suppress voltage oscillation in power supply path 35 while minimizing the occurrence of torque pulsation caused by low-pass filter 26. In addition, since the cutoff frequency of low-pass filter 26 is adjusted based on the operating state of motor 40, it is easy to prevent voltage oscillation.

[0034] The above-mentioned low-pass filter 26 is configured so that its cutoff frequency can be adjusted as appropriate according to the rotation speed and drive current of the motor 40, but instead of such a configuration, the low-pass filter 26 may be configured so that one frequency from among a plurality of frequencies can be selected in advance as the cutoff frequency. Then, by selecting one frequency from the plurality of frequencies as the cutoff frequency based on the rotation speed and drive current of the motor 40 and switching to that frequency, it is possible to suitably suppress voltage oscillation in the power supply path 35. Instead of being in the form of a digital filter, the low-pass filter 26 may be a filter configured with hardware such as resistor elements and capacitors. In such a case, multiple combinations of resistor elements and capacitors corresponding to multiple cutoff frequencies are included in the low-pass filter 26 in advance, and the cutoff frequency can be switched by selecting one of the combinations.

[0035] <Second adjustment method> Next, a second adjustment method for low-pass filter 26, which is a digital filter, for achieving both suppression of voltage oscillation and suppression of pulsation of motor 40 will be described with reference to the flowchart shown in Fig. 7. This adjustment method is repeatedly implemented at predetermined intervals by executing a predetermined control program in control unit 12 of motor control device 10.

[0036] In S201, the voltage of the power supply path 35 is detected. This detection is performed by a voltage sensor (not shown). Next, in S202, based on the detected voltage, it is determined whether or not voltage oscillation is occurring in the power supply path 35. Specifically, it can be determined that voltage oscillation is occurring when the rate of change in the amplitude of voltage oscillation exceeds a predetermined value. If an affirmative determination is made in S202, the process proceeds to S203, and if a negative determination is made, the process proceeds to S204.

[0037] In S203, the cutoff frequency of the low-pass filter 26 is adjusted to eliminate the voltage oscillation of the power supply path 35 as described above. Specifically, the cutoff frequency is adjusted to be lower as the voltage oscillation detected in S202 is larger. For example, the cutoff frequency may be adjusted to be lower as the amplitude of the voltage oscillation is larger. By such adjustment, the voltage oscillation of the power supply path 35 is reduced. However, depending on the state of the power supply to the motor control device 10, it is possible that the voltage oscillation that has already occurred is not sufficiently eliminated. Therefore, after the processing of S203, it is determined in S205 whether the oscillation has converged. This determination can also be made based on the rate of change in the amplitude of the voltage oscillation. If the determination in S205 is positive, this means that the voltage oscillation has converged after the adjustment of the cutoff frequency in S203, and the adjustment process in FIG. 7 is terminated as it is. On the other hand, if the determination in S205 is negative, this means that the voltage oscillation has not converged even after the adjustment of the cutoff frequency in S203. In this case, the process proceeds to S206, where the driving of the motor 40 is stopped. This makes it possible to reliably prevent the motor 40 from running out of control.

[0038] If a negative determination is made in S202 and the process proceeds to S204, the low-pass filtering process by low-pass filter 26 is bypassed in the same manner as in S104. That is, the operation of low-pass filter 26, which is a digital filter, is turned off, and the signal from subtractor 25 is directly input to current controller 27. As an alternative to S204, if an appropriate frequency has already been set as the cutoff frequency of low-pass filter 26 (for example, if the process of S203 has been performed previously), low-pass filtering process by low-pass filter 26 may be performed instead of bypassing the low-pass filtering process.

[0039] 7, the suppression of voltage oscillation by low-pass filter 26 is limited to the cases when voltage oscillation (vibration) actually occurs. Therefore, it is possible to suitably suppress voltage oscillation in power supply path 35 while minimizing the occurrence of torque pulsation caused by low-pass filter 26. Furthermore, if voltage oscillation cannot be sufficiently eliminated even by low-pass filter 26, motor 40 is stopped, so that the safety of the user is suitably maintained.

[0040] <Appendix 1> A DC power source (30); Each of the servo motors (40) includes one or more motor control devices (1 0) and a power supply path (35) that distributes and supplies power from the DC power source (30) to the one or more motor control devices (10); A servo DC power supply system comprising: The one or more motor control devices (10) each include a detection unit that detects a servo input terminal voltage (Vb) input to the motor control device (10) from the power supply path (35); a current control loop section (20) for controlling a current flowing to the servo motor by a current control loop using a signal that has been subjected to a predetermined filtering process for attenuating the high frequency side of the servo input voltage (Vb) in accordance with a frequency related to voltage oscillation in the servo DC power supply system; an adjustment unit (12) that adjusts a frequency band associated with the predetermined filtering process based on a predetermined parameter related to the voltage oscillation; A servo DC power supply system comprising:

[0041] <Appendix 2> A motor control device (10) that controls a servo motor (40) using power supplied from a DC power source (30) via a power supply path (35) in a servo DC power supply system, a detection unit that detects a servo input terminal voltage (Vb) input to the motor control device (10) from the power supply path (35); a current control loop section (20) for controlling a current flowing to the servo motor by a current control loop using a signal that has been subjected to a predetermined filtering process for attenuating the high frequency side of the servo input voltage (Vb) in accordance with a frequency related to voltage oscillation in the servo DC power supply system; an adjustment unit (12) that adjusts a frequency band associated with the predetermined filtering process based on a predetermined parameter related to the voltage oscillation; A motor control device (10) comprising:

[0042] <Appendix 3> A method for controlling a servo motor (40) by a motor control device (10) having a current control loop for controlling a drive current flowing through the servo motor (40), the motor control device (10) receiving power from a DC power source (30) via a power supply path (35) in a servo DC power supply system, comprising: detecting a servo input terminal voltage (Vb) input to the motor control device (10) from the power supply path (35); performing a predetermined filtering process on the servo input voltage (Vb) to attenuate the high frequency side of the servo input voltage in accordance with a frequency associated with voltage oscillations in the servo DC power supply system; controlling a current flowing through the servo motor (40) by a current control loop using the signal obtained by the predetermined filtering process; A method for controlling a servo motor comprising: [Explanation of symbols]

[0043] 10 Motor control device 11 Inverter circuit 12 Control section 15 Smoothing capacitor 20 Current control loop section 21,23,25 Subtractor 22 Position Controller 24 Speed ​​Controller 26 Low-pass filter 27 Current control section 28 Current Sensor 29 Speed ​​detector 30 DC power supply 35 Power supply path 40 Servo motor 41 Encoder 50 Three-phase AC power supply

Claims

1. A DC power source; one or more motor control devices each controlling a corresponding servo motor; a power supply path that distributes and supplies power from the DC power source to the one or more motor control devices; A servo DC power supply system comprising: Each of the one or more motor control devices is a detection unit that detects a servo input terminal voltage input to the motor control device from the power supply line; a current control loop section for inputting a signal that has been subjected to a predetermined filtering process on the servo input terminal voltage to a current controller, and controlling a current flowing through the servo motor by the current controller; an adjustment unit that adjusts a frequency band to be filtered by the predetermined filtering process based on at least one of a rotation speed of the corresponding servo motor and a drive current flowing through the corresponding servo motor so that the frequency band becomes lower as the rotation speed increases and / or the frequency band becomes lower as the drive current increases; A servo DC power supply system comprising:

2. A DC power source; one or more motor control devices each controlling a corresponding servo motor; a power supply path that distributes and supplies power from the DC power source to the one or more motor control devices; A servo DC power supply system comprising: Each of the one or more motor control devices is a detection unit that detects a servo input terminal voltage input to the motor control device from the power supply line; a current control loop section for inputting a signal that has been subjected to a predetermined filtering process on the servo input terminal voltage to a current controller, and controlling a current flowing through the servo motor by the current controller; When a voltage oscillation is detected in the servo DC power supply system, the frequency band to be filtered by the predetermined filtering process is lowered as the amplitude of the oscillation increases. An adjustment unit for adjusting a wavenumber band; A servo DC power supply system comprising:

3. When the voltage oscillation does not converge after the frequency band is adjusted by the adjustment unit, driving of the corresponding servo motor is stopped.

3. The servo DC power supply system of claim 2.

4. A motor control device that controls a servo motor using power supplied from a DC power source through a power supply line in a servo DC power supply system, a detection unit that detects a servo input terminal voltage input to the motor control device from the power supply line; a current control loop section for inputting a signal that has been subjected to a predetermined filtering process on the servo input terminal voltage to a current controller, and controlling a current flowing through the servo motor by the current controller; an adjustment unit that adjusts a frequency band to be filtered by the predetermined filtering process based on at least one of a rotation speed of the servo motor and a drive current flowing through the servo motor so that the frequency band becomes lower as the rotation speed increases and / or the frequency band becomes lower as the drive current increases; A motor control device comprising:

5. A motor control device that controls a servo motor using power supplied from a DC power source through a power supply line in a servo DC power supply system, a detection unit that detects a servo input terminal voltage input to the motor control device from the power supply line; a current control loop section for inputting a signal that has been subjected to a predetermined filtering process on the servo input terminal voltage to a current controller, and controlling a current flowing through the servo motor by the current controller; an adjustment unit that adjusts a frequency band when a voltage oscillation is detected in the servo DC power supply system based on the servo input terminal voltage so that a frequency band to be filtered by the predetermined filtering process becomes lower as the amplitude of the voltage oscillation increases; A motor control device comprising:

6. A method for controlling a servo motor by a motor control device having a current control loop for controlling a drive current flowing through the servo motor, the motor control device being supplied with power from a DC power source through a power supply line in a servo DC power supply system, comprising: detecting a servo input terminal voltage input to the motor control device from the power supply line; performing a predetermined filtering process on the servo input terminal voltage; inputting the signal obtained by the predetermined filtering process to a current controller, and controlling a current flowing through the servo motor by the current controller; the step of performing the predetermined filtering process further includes a process of adjusting a frequency band to be filtered by the predetermined filtering process so that the frequency band is lowered as the rotation speed is higher, and / or the frequency band is lowered as the drive current is higher, based on at least one of a rotation speed of the servo motor and a drive current flowing through the servo motor; A method for controlling a servo motor.

7. A method for controlling a servo motor by a motor control device having a current control loop for controlling a drive current flowing through the servo motor, the motor control device being supplied with power from a DC power source through a power supply line in a servo DC power supply system, comprising: detecting a servo input terminal voltage input to the motor control device from the power supply line; performing a predetermined filtering process on the servo input terminal voltage; inputting the signal obtained by the predetermined filtering process to a current controller, and controlling a current flowing through the servo motor by the current controller; The step of performing the predetermined filtering process further includes a process of adjusting a frequency band when a voltage oscillation is detected in the servo DC power supply system such that a frequency band to be filtered by the predetermined filtering process becomes lower as the amplitude of the oscillation increases. A method for controlling a servo motor.

8. The predetermined filtering process is a process using a low-pass filter, a cutoff frequency of the predetermined filtering is adjusted based on a predetermined parameter indicative of voltage oscillations in the servo DC power supply system; 8. A method for controlling a servo motor according to claim 6 or 7.

Images