JP2019068666A - Shaft torsional vibration suppression controller - Google Patents

Abstract

To provide a shaft torsional vibration suppression control arrangement for suppressing resonance of shaft torsional vibration by determining presence of resonance of shaft torsional vibration and the possible cause, and correcting operation parameters of a motor speed controller.SOLUTION: A shaft torsional vibration suppression control arrangement includes a frequency calculator for calculating the data of a frequency region related to the shaft toque of a coupling shaft, a shaft torsional vibration resonance determination unit for determining presence of resonance of a shaft torsional vibration system on the basis of the data of the frequency region, and determining the possible cause thereof when a determination is made that there is resonance, a speed response gain correction value generation unit for correcting the speed response gain, when a determination is made that the possible cause of resonance is the speed response gain for setting the speed response of the motor, and a carrier frequency correction value generation unit for correcting the carrier frequency when a determination is made that the possible cause of resonance is torque ripple occurring by te carrier frequency of PWM control.SELECTED DRAWING: Figure 1

Description

  An embodiment of the present invention relates to a shaft torsional vibration suppression control device used in a motor speed control device for driving a motor connected with a mechanical load having shaft torsional vibration characteristics.

  Conventionally, when driving a motor to which a mechanical load having shaft torsional vibration characteristics is connected, the gain of the speed response is adjusted in advance so that the speed response is sufficiently separated from the natural frequency of the mechanical system including the connection shaft. The resonance of the torsional vibration of the connecting shaft is suppressed. In addition, for example, when power pulsates due to switching of the variable speed control device, torque ripple occurs, but by setting the carrier frequency of switching so that this torque ripple and mechanical system do not resonate, resonance of torsional vibration of the connecting shaft To suppress.

  As a leading example of a motor control device connected with a mechanical load having shaft torsional vibration characteristics, in Patent Document 1, the shaft torsional vibration compensation value is corrected according to the speed difference between the motor speed and the mechanical load speed. There has been proposed a motor control device capable of suppressing an overshoot of the speed response and making the speed of the mechanical load respond to the speed command value with a short rise time.

Japanese Patent Application Laid-Open No. 7-15591

  However, since the carrier frequency and the speed response gain are fixed values that are set in advance, there is a resonance point that can not be grasped in advance, a change in shaft spring constant due to aging deterioration, a change in inertia moment due to replacement of the machine load itself, etc. If the natural frequency of the shaft changes, it may be difficult to prevent excessive torsional vibration that resonates.

  Further, Patent Document 1 describes that the motor control device has a control characteristic that suppresses torsional vibration of the shaft, but prevents the resonance phenomenon between the speed response, the torque ripple, and the natural frequency of the mechanical system. There is no mention about that.

  The embodiment is made to solve the problems as described above, and determines the presence and the cause of the resonance of the shaft torsional vibration, and corrects the resonance of the shaft torsional vibration by correcting the operation parameter of the motor speed control device. It is an object of the present invention to provide a shaft torsional vibration suppression control device that suppresses vibration.

  A shaft torsional vibration suppression control device according to an embodiment mechanically couples a motor driven by a motor speed control device based on PWM control, a mechanical load driven by the motor, the motor and the mechanical load. And suppressing the vibration due to the resonance of the shaft torsional vibration system including the connecting shaft. The shaft torsional vibration suppression control device determines the presence or absence of resonance of the shaft torsional vibration system based on a frequency computing unit that calculates data of a frequency domain related to shaft torque of the connection shaft, and data of the frequency domain. A shaft torsional vibration resonance determination unit that determines the cause when it is determined that there is resonance, and the speed response gain when it is determined that the cause of the resonance is due to a speed response gain that sets the speed response of the motor A speed response gain correction value generation unit for correcting the carrier frequency correction value generation unit for correcting the carrier frequency when it is determined that the cause of the resonance is due to a torque ripple generated by the carrier frequency of the PWM control; And.

  In the present embodiment, since the shaft torsional vibration resonance determination unit is provided, it is possible to determine the presence or absence of resonance of the shaft torsional vibration system, and to determine the cause when it is determined that the resonance is present. In addition, since the embodiment includes the speed response gain correction value generation unit and the carrier frequency correction value generation unit, it is possible to correct the operation parameter of the motor speed control device according to the cause of the resonance.

FIG. 1 is a block diagram illustrating a shaft torsional vibration suppression control device according to a first embodiment. FIG. 8 is a block diagram illustrating a shaft torsional vibration suppression control device according to a second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of sizes between parts, and the like are not necessarily the same as the actual ones. In addition, even in the case of representing the same portion, the dimensions and ratios may be different from one another depending on the drawings.
In the specification of the present application and the drawings, the same elements as those described above with reference to the drawings are denoted by the same reference numerals, and the detailed description will be appropriately omitted.

Embodiment 1
FIG. 1 is a block diagram illustrating a shaft torsional vibration suppression control device according to a first embodiment.
FIG. 1 also shows the configuration of the motor speed control device 20 in addition to the configuration of the shaft torsional vibration suppression control device 30. The shaft torsional vibration suppression control device may be housed in the same housing or cabinet as the motor speed control device, or may be housed in another physically separated housing or the like.

  As shown in FIG. 1, the motor speed control device 20 is connected to the motor 1, the speed detector 4, and the shaft torsional vibration suppression control device 30. The motor speed control device 20 controls the motor 1 so that the actual speed of the motor 1 detected by the speed detector 4 matches the separately supplied speed command value. The motor speed control device 20 sets the operation parameters in accordance with the correction value supplied from the shaft torsional vibration suppression control device 30 so that the resonance of the shaft torsional vibration system consisting of the motor 1, the mechanical load 2 and the connecting shaft 3 is generated. It can operate with the vibration suppressed.

  The motor 1 is connected at its connecting shaft 3 to its rotary shaft and a mechanical load 2 having torsional vibration characteristics. The driving torque of the motor 1 is transmitted to the mechanical load 2 via the connecting shaft 3. The motor speed control device 20 drives the motor 1 with variable speed control. For example, the motor 1 is a motor driven by AC power, such as an induction motor or a synchronous motor. For example, the motor speed control device 20 is an inverter device that drives an induction motor, a synchronous motor, and the like.

  Motor speed control device 20 includes a speed response gain multiplication unit 5, a current controller 6, and a power converter 7. The speed response gain multiplication unit 5 multiplies the speed response gain by the speed deviation between the speed command value and the speed detected by the speed detector 4 of the motor 1 to generate a drive torque command value. The speed command value is supplied from, for example, a programmable controller (PLC) or the like. In the speed response gain multiplication unit 5, when the speed response gain is increased, the speed response (frequency) is improved, and when the speed response gain is decreased, the speed response (frequency) is decreased.

  The current controller 6 is connected to the output of the speed response gain multiplication unit 5. The current controller 6 outputs a control amount generated in accordance with the difference between the command value of the drive torque supplied from the speed response gain multiplication unit 5 and the torque current component supplied to the motor 1.

  The power converter 7 is connected to the output of the current controller 6. The power converter 7 is a converter under PWM control. The power converter 7 outputs a voltage and a current for driving the motor 1 in accordance with the control amount generated by the current controller 6.

  An axial torque detector 8 is provided on the connecting shaft 3. The shaft torque detector 8 supplies data of the detected shaft torque to the shaft torsional vibration suppression control device. The shaft torsional vibration suppression control device 30 determines, based on the supplied shaft torque data, whether or not resonance occurs in the shaft torsional vibration system. When resonance occurs in the shaft torsional vibration system, the shaft torsional vibration suppression control device 30 corrects the gain value of the speed response gain multiplication unit 5 or the carrier frequency of the PWM control of the power converter 7 Correct the

The configuration of the shaft torsional vibration suppression control device 30 will be described in detail.
The shaft torsional vibration suppression control device 30 includes a frequency calculator 9, a torsional vibration resonance determination unit 10, a speed response gain correction value generation unit 11, and a carrier frequency correction value generation unit 12.

  The frequency calculator 9 is connected to the output of the shaft torque detector 8. The frequency calculator 9 converts axial torque data in the time domain detected by the axial torque detector 8 into data in the frequency domain. The frequency calculator 9 is, for example, an FFT (Fast Fourier Transform) analyzer.

  The torsional vibration resonance determination unit 10 is connected to the output of the frequency calculator 9. In the torsional vibration resonance determination unit 10, the shaft torsional vibration system consisting of the motor 1, the mechanical load 2 and the connecting shaft 3 generates vibration due to resonance based on data of shaft torque in the frequency domain (hereinafter, resonance is simply generated) It is determined whether or not. When the torsional vibration resonance determination unit 10 determines that the shaft torsional vibration system generates resonance, it determines whether it is resonance by the speed response gain or by torque ripple based on the carrier frequency of PWM control. .

  For example, the torsional vibration resonance determination unit 10 has a threshold value T0 regarding the axial torque that is not related to the frequency. The torsional vibration resonance determination unit 10 determines that resonance occurs when the data of the axial torque in the frequency domain is equal to or greater than this threshold value T0. The torsional vibration resonance determination unit 10 determines that resonance does not occur when the data of the shaft torque in the frequency domain is smaller than the threshold value T0.

  If the data of the shaft torque in the frequency domain is equal to or more than the threshold value T0, it is considered that the data of the shaft torque takes a peak value centered on any frequency. The torsional vibration resonance determination unit 10 determines which component of the motor speed control device 20 the vibration of the shaft torsional vibration system is caused by the frequency at which the data of the shaft torque has a peak value.

  Specifically, the torsional vibration resonance determination unit 10 determines whether the resonance is due to the speed response gain of the speed response gain multiplication unit 5 or whether the resonance is due to torque ripple based on the carrier frequency of PWM (Pulse Width Modulation) of the power converter 7. judge.

  For example, the torsional vibration resonance determination unit 10 uses the carrier frequency of the power converter 7 and its harmonic component as a frequency for determination. Specifically, when the carrier frequency fc of the power converter 7 and the operating frequency f0 of the motor 1 are used, the frequency fn for determination is n × (fc ± f0), n = 1, 2, 3,. It is set to (natural number). In the torsional vibration resonance determination unit 10, a threshold value Tn is set in advance for each frequency fn for determination.

  The setting of the frequency fn for determination is not limited to the above, and can be set appropriately. The frequency fn may be set by further expanding the range to n × (fc ± f0), for example, n × (fc ± k × f0) (k> 1). In the case of fc >> f0, etc., the frequency may be set as fn = n × fc.

  The torsional vibration resonance determination unit 10 determines that resonance due to torque ripple based on the carrier frequency is generated when data of shaft torque equal to or greater than the set threshold value Tn is detected at any of the frequencies of fn. judge.

  The torsional vibration resonance determination unit 10 determines that resonance due to the speed response gain is generated when data of shaft torque equal to or greater than the set threshold value Tn is not detected at any of the frequencies fn.

  The speed response gain correction value generation unit 11 and the carrier frequency correction value generation unit 12 are connected to the output of the torsional vibration resonance determination unit 10, respectively. The torsional vibration resonance determination unit 10 supplies the enable signal to the speed response gain correction value generation unit 11 when it determines that the resonance is caused by the speed response gain. The enable signal causes the speed response gain correction value generation unit 11 to operate. The speed response gain correction value generation unit 11 that has received the enable signal generates a correction value of the speed response gain, and supplies the correction value to the speed response gain multiplication unit 5.

  The torsional vibration resonance determination unit 10 supplies the enable signal to the carrier frequency correction value generation unit 12 when it determines that the resonance is caused by the torque ripple based on the carrier frequency. The enable signal causes the carrier frequency correction value generation unit 12 to operate. The carrier frequency correction value generation unit 12 that has received the enable signal generates a correction value of the carrier frequency and supplies the correction value to the power converter 7.

The operation of the shaft torsional vibration suppression control device 30 according to the present embodiment will be described.
The data of the axial torque in the time domain is detected by the axial torque detector 8 and supplied to the frequency calculator 9.

  The frequency calculator 9 converts axial torque data in the time domain into data in the frequency domain. The converted data of the shaft torque is supplied to the torsional vibration resonance determination unit 10.

  The torsional vibration resonance determination unit 10 compares the supplied axial torque data at all frequencies with a threshold value T0 that is constant with respect to the frequency. The torsional vibration resonance determination unit 10 determines that the torsional vibration resonance is not generated when the data of the shaft torque is smaller than the threshold value T0 at all the frequencies fn. The motor speed controller 20 maintains the current operation.

  When the torque torque data is equal to or greater than the threshold value T0, the torsional vibration resonance determination unit 10 compares the shaft torque data for each frequency fn with the threshold value Tn set for each frequency fn. The frequency fn for which the threshold is set is set based on the carrier frequency of the power converter 7. The frequency fn is n × (fc ± f0). Here, n is a natural number, fc is a carrier frequency, and f 0 is an operating frequency of the motor 1.

  The threshold values T1, T2,... Are set for f1, f2,. The threshold values T1, T2,... May be different values, or some or all of them may be the same value. For example, the threshold value Tn is set based on a value measured by an experiment or the like or a value obtained by a simulation or the like.

  If the data of the axial torque is equal to or greater than the threshold value Tn at any frequency fn, the torsional vibration resonance determination unit 10 supplies an enable signal to the carrier frequency correction value generation unit 12.

  The carrier frequency correction value generation unit 12 generates a correction value of the carrier frequency fc. The correction value of the carrier frequency fc is generated, for example, by obtaining the value of the carrier frequency fc from the power converter 7 and multiplying it by a preset coefficient α (0 <α <1). α is set to, for example, 1% (0.01). For example, the carrier frequency correction value generation unit 12 calculates a new carrier frequency (1 + α) × fc using the coefficient α. The calculated new carrier frequency is supplied to the power converter 7. The carrier frequency correction value generation unit 12 also supplies a new carrier frequency to the frequency calculator 9, and the frequency calculator 9 updates the frequency fn for determination to a new carrier frequency.

  The power converter 7 updates the carrier frequency value to (1 + α) × fc, and resumes operation or continues.

  The above operation is repeated until the data of shaft torque falls below the threshold at all frequencies n × (fc ± f 0).

  The upper limit of the carrier frequency that can be updated is provided, and even if the upper limit value is reached, if the axial torque data does not fall below the threshold Tn, the new carrier frequency is (1-α) × fc Thus, the carrier frequency may be corrected to decrease with respect to the initial value. Furthermore, the lower limit of the correction value may be provided, and the carrier frequency correction value generation unit 12 may generate an alarm if the shaft torque data does not fall below the threshold value even if the lower limit value is reached.

  The upper and lower limits of the correction range of the carrier frequency are set, for example, as ± 5% (± 0.05). By setting the upper and lower limits in the correction range of the carrier frequency, it is possible to avoid the reduction of the efficiency of the power converter 7 and the increase of noise generation.

  The torsional vibration resonance determination unit 10 outputs an enable signal to the speed response gain correction value generation unit 11 when the data of the shaft torque is equal to or greater than the threshold value T0 and smaller than the threshold value Tn corresponding to each frequency fn. Supply.

  The speed response gain correction value generation unit 11 receiving the enable signal generates a correction value of the speed response gain G. The speed response gain correction value generation unit 11 is generated, for example, by acquiring the current value of the speed response gain G from the speed response gain multiplication unit 5 and multiplying the value by a preset coefficient β (0 <β <1). . The coefficient β is set to, for example, 5% (0.05). The velocity response gain multiplication unit 5 calculates a new velocity response gain (1 + β) × G using the coefficient β. The calculated new velocity response gain is supplied to the velocity response gain multiplication unit 5.

  The velocity response gain multiplication unit 5 updates the velocity response gain to (1 + β) × G and resumes the operation.

  The above operation is repeated until the data of the shaft torque falls below the threshold value T0.

  As in the case of the carrier frequency correction value generation unit 12, upper and lower limits may be set for the correction value of the speed response gain, and the data of the shaft torque may be compared with the threshold value T0 within the upper and lower limits of the correction value. By setting in this manner, it is possible to prevent the response speed to the load fluctuation from being reduced to an unacceptable level or the speed response becoming too fast to cause overshoot or the like.

  When the data of the shaft torque becomes smaller than the threshold value T0 by the above-mentioned correction, the motor speed control device 20 resumes the operation with the updated speed response gain.

  The calculation of the correction value of each of the carrier frequency fc and the speed response gain G is not limited to the above and can be appropriately set. For example, each correction value may be set in advance by experiment or the like, stored in a table as values α1, α2,... According to the number of corrections, read out for each number of corrections, and applied. Alternatively, the new carrier frequency may be calculated as a power of the number of corrections i as α ^ ixf, with 1 <α <2.

  The shaft torsional vibration suppression control device 30 may be realized by, for example, a central processing unit (CPU) that develops a program stored in a storage device (not shown) or sequentially reads and executes each step of the program. . Some or all of the above-described components are part of a program executed by the CPU. When the CPU executes and realizes the operation of the motor speed control device 20, the program of the shaft torsional vibration suppression control device 30 may be executed by the CPU of the motor speed control device 20.

  The shaft torsional vibration suppression control device 30 may be realized by a PLC. The shaft torsional vibration suppression control device 30 may be realized as part of a program of a PLC that supplies a speed command value to the motor speed control device 20 or may be realized by another PLC.

The effects of the shaft torsional vibration suppression control device 30 of the present embodiment will be described.
Since the shaft torsional vibration suppression control device 30 of the present embodiment includes the frequency calculator 9 and the torsional vibration resonance determination unit 10, it is possible to determine the presence or absence of the torsional vibration resonance by frequency analysis of the measured value of the shaft torque. . When the torsional vibration resonance is included in the frequency component of the axial torque, the torsional vibration resonance determination unit 10 generates harmonics due to torque ripple based on the carrier frequency of PWM from the resonance frequency, or is based on the speed response gain. It can be determined whether there is. Therefore, by correcting the operating parameters of the motor speed control device 20 according to the respective causes, the resonance state can be released. Therefore, the shaft torsional vibration suppression control device 30 can suppress the resonance of the shaft torsional vibration.

  In the above description, the carrier frequency and the velocity response gain are corrected in the direction increasing from the initial value of the operation parameter, and when the resonance state is not eliminated, the correction is performed in the direction decreasing from the initial value. It is not limited to After the correction is made in the direction of decreasing from the initial value of the operating parameter, an appropriate correction value may be searched in the direction of increasing from the initial value. Also, when searching for an appropriate correction value, the correction value may be switched by a learning function that stores the search history and achieves the shortest search time.

  The shaft torsional vibration suppression control device 30 may be realized by a CPU (Central Processing Unit) or the like that develops a program stored in a storage device (not shown) and sequentially executes each step of the program. Some or all of the components of the shaft torsional vibration suppression control device 30 described above are implemented as part of a program. The motor speed control device 20 may be executed by a CPU or the like, in which case the program for realizing the shaft torsional vibration suppression control device 30 may be executed by the CPU of the motor speed control device 20 or separately. May be executed by the CPU of

  The shaft torsional vibration suppression control device 30 may be realized by a PLC. Some or all of the components of the shaft torsional vibration suppression control device 30 are realized by the program of the PLC. The PLC that implements the shaft torsional vibration suppression control device 30 may be the same as the PLC that supplies the speed command value to the motor speed control device 20, or may be another PLC.

Second Embodiment
Parameters other than axial torque data detected by the torque detector can also be used as the axial torque data for determining the presence or absence of torsional vibration resonance of the axial torsional vibration system.
FIG. 2 is a block diagram illustrating a shaft torsional vibration suppression control device according to 2 of the embodiment.
As shown in FIG. 2, the shaft torsional vibration suppression control device 130 according to the second embodiment is calculated based on data of voltage and current output from the power converter 7 instead of actual data of shaft torque by the torque detector. The calculated value of shaft torque is used.

  The shaft torsional vibration suppression control device 130 includes a magnetic flux calculating unit 13 and a torque calculating unit 14. The shaft torsional vibration suppression control device 130 of the second embodiment is different from the case of the first embodiment described above in that it includes the magnetic flux calculating unit 13 and the torque calculating unit 14, and in the other points, the first embodiment. Is the same as in The same components as in the first embodiment will be assigned the same reference numerals and detailed descriptions thereof will be omitted as appropriate.

  The magnetic flux calculator 13 is connected to the power converter 7. The magnetic flux operation unit 13 acquires data of voltage and current output from the power converter 7 from the power converter 7. The magnetic flux calculator 13 calculates the magnetic flux based on the voltage and current data output from the power converter 7 and the winding resistance value of the motor 1. The winding resistance value of the motor 1 is preset by measurement or the like.

  The torque calculator 14 is connected to the output of the magnetic flux calculator 13. The torque calculator 14 calculates the value of the axial torque based on the value of the magnetic flux calculated by the magnetic flux calculator 13. The calculated value of the axial torque is supplied to the frequency calculator 9 to determine and correct the torsional vibration resonance as in the case of the first embodiment described above.

  The shaft torsional vibration suppression control device 130 according to the first embodiment can use the value of the shaft torque obtained by the calculation. Therefore, even if it is difficult to attach the shaft torque detector, it is possible to determine the presence / absence of the torsional vibration resonance and to suppress the shaft torsional vibration resonance.

  According to the embodiment described above, it is possible to realize the shaft torsional vibration suppression control device which suppresses the resonance of the shaft torsional vibration by judging the presence and the cause of the resonance of the shaft torsional vibration and correcting the operation parameter of the motor speed control device. can do.

  While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the scope of equivalents thereof. In addition, the embodiments described above can be implemented in combination with each other.

  Reference Signs List 1 motor 2 mechanical load 3 connected shaft 4 speed detector 5 speed response gain multiplication unit 6 current controller 7 power converter 8-axis torque detector 9 frequency calculator 10 torsional vibration resonance determination unit 11 Speed response gain correction value generation unit 12 Carrier frequency correction value generation unit 13 Magnetic flux calculation unit 14 Torque calculation unit 20 Motor speed control device 30, 130 axis torsional vibration suppression control device

Claims (7)

A shaft torsional vibration system including a motor driven by a motor speed controller based on PWM control, a mechanical load driven by the motor, and a connecting shaft mechanically connecting the motor and the mechanical load. A shaft torsional vibration suppression control device that suppresses vibration due to resonance,
A frequency calculator for calculating data of a frequency domain related to an axial torque of the connecting shaft;
An axis torsional vibration resonance determination unit that determines presence or absence of resonance of the shaft torsional vibration system based on data in the frequency domain, and determines a cause when it is determined that resonance is present,
A speed response gain correction value generation unit that corrects the speed response gain when it is determined that the cause of the resonance is a speed response gain that sets a speed response of the motor;
A carrier frequency correction value generation unit that corrects the carrier frequency when it is determined that the cause of the resonance is due to a torque ripple generated by the carrier frequency of the PWM control;
Shaft torsional vibration suppression control device equipped with   The shaft torsional vibration suppression control device according to claim 1, wherein the frequency calculator inputs data of the shaft torque detected by a shaft torque detector provided on the connection shaft.   The shaft torsional vibration suppression control device according to claim 1, wherein the frequency computing unit inputs data of the shaft torque calculated based on values of voltage and current output from the motor speed control device.   2. The shaft torsional vibration suppression control device according to claim 1, further comprising a torque calculation unit that calculates data of the shaft torque based on values of voltage and current output from the motor speed control device and supplies the data to the frequency calculator. . The speed response gain correction value generation unit calculates a new speed response gain set based on the initial value of the speed response gain as a speed response gain correction value, and the motor speed control device calculates the speed response gain correction value. Send to
The shaft torsional vibration resonance determination unit determines the presence or absence of the resonance based on new data of the shaft torque acquired by the resumed operation of the motor speed control device. The shaft torsional vibration suppression control device according to claim 1. The carrier frequency correction value generation unit calculates a new carrier frequency set based on the initial value of the carrier frequency as a carrier frequency correction value, and transmits the carrier frequency correction value to the motor speed control device.
The shaft torsional vibration resonance determination unit determines the presence or absence of the resonance based on new data of the shaft torque acquired by the resumed operation of the motor speed control device. The shaft torsional vibration suppression control device according to claim 1.   The axis according to claim 6, wherein the speed response gain correction value generation unit and the carrier frequency correction value generation unit include a learning function for setting the speed response gain correction value and the carrier frequency correction value optimum in the shortest search time. Torsional vibration suppression controller.

Images