JP3857253B2 - Suspended centrifuge and motor drive control method in suspended centrifuge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a suspended centrifuge in which a rotating drum is coupled to a motor via a flexible coupling, and a motor drive control method in the suspended centrifuge.
[0002]
[Prior art]
Suspended centrifuges are frequently used for mechanical separation operations of solids and moisture such as slurry dehydration in the fields of food, medicine, sugar production, chemistry and wastewater treatment. In this suspended centrifuge, a rotating drum is suspended in a housing so as to be rotatable via a flexible coupling with a motor. This rotary drum is operation-controlled at an arbitrary rotational speed by a motor that is rotationally driven by an AC output from an inverter (see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-159882
[Problems to be solved by the invention]
By the way, the environment in which the above-described suspended centrifuge is installed is often high temperature and high humidity. Therefore, an external mechanical rotational speed detector that is essential for rotational speed detection is likely to fail. In addition, since the equipment is stopped and maintenance is performed, the production efficiency is reduced. Therefore, it is desired that the components of the suspended centrifuge have high reliability and are less likely to cause failure. However, if the rotational speed detector is simply removed so as not to cause a failure, it becomes difficult to control the rotational speed of the heavy rotating drum, resulting in overshoot, undershoot, etc., resulting in unstable operation. turn into.
[0005]
The present invention has been made in view of the above circumstances, and applies a permanent magnet type synchronous motor to a suspended centrifuge and a novel drive control for adapting the characteristics of the motor to the suspended centrifuge. By adopting this method, we provide suspended centrifuges and motor drive control methods for suspended centrifuges that reduce overshoots and undershoots and eliminate the need for regular maintenance. The purpose is to do.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is a suspended centrifuge in which a rotating drum is coupled to a motor via a flexible coupling, and the deviation amount of the target rotational speed of the motor is set to a first value. When advance compensation control is performed by a combination of feedforward control, variable PI control, and equivalent disturbance compensation control according to the load inertia amount until the value reaches a value, and the deviation amount of the target rotational speed becomes the first set value The motor drive control unit performs fixed PI control, and the motor drive control unit performs the advance compensation control according to the load inertia amount until the deviation amount of the rotation speed of the motor reaches a second set value. using the second set value below a third set value of the rated inertia weight (e.g., 10% or less) the system inertia amount automatic compensation function generator for generating a function for sequentially reduced until And it said that there were pictures.
[0007]
According to the present invention, the motor drive control unit compensates the advance according to the load inertia amount until the deviation amount of the target rotation speed reaches the first set value (for example, 3%, corresponding to 97% of the target rotation speed). By performing the control and performing the fixed PI control when the first set value (for example, 3%) is reached, the power regeneration that repeatedly starts and accelerates / decelerates the rotating drum having a large inertial energy in a short cycle. Therefore, it is possible to provide a suspended centrifuge that can adapt the characteristics of the motor that can be used to the centrifuge, reduce overshoot and undershoot, and realize stable operation.
[0009]
According to the present invention, the system inertia amount automatic compensation function generation unit uses the lead compensation control according to the load inertia amount until the second set value (for example, 25%) of the maximum rotation speed of the motor is used, and the second compensation control is performed. If the set value is less than or equal to the set value, continuously or stepwise to the third set value (for example, about 10%) of the rated inertia amount, the compensation amount is lowered to reduce the compensation amount. It is possible to provide a suspended centrifuge that controls the generation of abnormal noise.
[0010]
Further, in the present invention, a permanent magnet type synchronous motor is used as the motor, the rotational speed is calculated using the magnetomotive force of the permanent magnet embedded in the rotor, and the motor drive control unit is notified. To do.
[0011]
According to the present invention, since it is possible to calculate the number of rotations using the phenomenon of magnetomotive force generated by a permanent magnet built in the motor, there is no need to externally install a mechanical rotation speed sensor. In addition to eliminating the need for an interlock, an interlock for preventing overspeed can be realized.
[0012]
Further, in the present invention, the motor drive control unit gives a deviation between a setting input inputted as an instruction value to the motor and a state quantity of the motor, and a transfer function including a proportional gain and an integral gain to the motor. It has a variable PI control part which stabilizes operation by applying.
[0013]
In the present invention, the motor drive control unit may include a feedforward control unit that maintains a difference between the setting input and the state quantity at zero.
[0014]
In the present invention, the motor drive control unit includes a load inertia amount that affects an operation characteristic of the motor, and an equivalent disturbance compensation control unit that reduces the influence of the parameter variation.
Further, the present invention is a suspended centrifuge in which a rotating drum is coupled to a motor via a flexible coupling, and the load is maintained until the deviation amount of the target rotational speed of the motor reaches a first set value. Advance compensation control is performed by a combination of feedforward control, variable PI control, and equivalent disturbance compensation control in accordance with the inertia amount, and fixed PI control is performed when the deviation amount of the target rotational speed reaches the first set value. Having a motor drive control unit, using a permanent magnet type synchronous motor for the motor, calculating the rotational speed using the magnetomotive force of the permanent magnet embedded in the rotor, and notifying the motor drive control unit Features.
[0015]
In order to solve the above-described problem, the present invention provides a motor drive control method for a suspended centrifuge in which a rotary drum is coupled to a motor via a flexible coupling, and includes a deviation amount of a target rotational speed of the motor. Lead compensation control by a combination of feedforward control, variable PI control, and equivalent disturbance compensation control is performed according to the load inertia amount until the first set value is reached, and the deviation amount of the target rotational speed is set to the first setting value. There line fixed PI control when it becomes the value until the deviation of the rotational speed of the motor becomes the second set value the process proceeds with compensation control according to the load inertia weight, the second set value In the following, a function for sequentially decreasing the rated inertia amount until the third set value is obtained is generated .
The present invention is also a motor drive control method in a suspended centrifuge in which a rotary drum is coupled to a motor via a flexible coupling, wherein the deviation amount of the target rotational speed of the motor is a first set value. Lead compensation control by a combination of feedforward control, variable PI control, and equivalent disturbance compensation control is performed according to the load inertia amount until the target rotational speed deviation amount reaches the first set value. A fixed PI control is performed, a permanent magnet type synchronous motor is used as the motor, a rotational speed is calculated using a magnetomotive force of a permanent magnet embedded in a rotor, and the motor drive control unit is notified. To do.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing an embodiment of a motor drive control unit of a suspended centrifuge according to the present invention.
As shown in FIG. 1, the motor drive control unit 1 is between a parameter setting unit 2 that gives a rotational speed command and a detection feedback signal, and a control object 3 that is composed of a load having a large mass and a large inertial energy, such as a rotary drum. Lead compensation control is performed by a combination of feedforward control, variable PI control, and equivalent disturbance compensation control according to the load inertia amount until the deviation amount of the target rotational speed of the motor reaches the first set value. Fixed PI control is performed when the deviation amount reaches the first set value.
Therefore, the motor drive control unit 1 includes a variable PI control unit 11, a feedforward control unit 12, an equivalent disturbance compensation control unit 13, and a system inertia amount automatic compensation function generation unit 14.
[0017]
The variable PI control unit 11 applies a transfer function composed of a proportional gain and an integral gain to the deviation between the setting input inputted as an instruction value and the state quantity of the motor to the motor, stabilizes the operation, and feedforward control The unit 12 maintains the difference between the setting input and the state quantity at 0, and the equivalent disturbance compensation control unit 13 has a function of reducing the influence of the load inertia amount that influences the operation characteristics of the motor and the parameter variation, By performing drive control using these combinations, a robust and high-speed response is possible with respect to the controlled object 3.
A mechanism for performing lead compensation control by a combination of the variable PI control unit 11, the feedforward control unit 12, and the equivalent disturbance control unit 13 is well known from Japanese Patent No. 2770461, Japanese Patent No. 2850075, and Japanese Patent No. 2850076.
[0018]
Further, the system inertia amount automatic compensation function generation unit 14 uses the advance compensation control according to the load inertia amount until the set value of the maximum rotation speed of the motor (for example, 25% of the target rotation speed) is reached. Below the set value, it has a function of generating a function for sequentially reducing the rated inertia amount until the third set value is reached.
The drive motor, which is a component of the suspended centrifuge in the present invention, uses a permanent magnet type synchronous motor, and calculates the rotational speed using the magnetomotive force of the permanent magnet embedded in the rotor. And the motor drive control unit 1 is notified.
[0019]
FIG. 2 is a flowchart cited for explaining the operation of the embodiment of the present invention. The operation of the embodiment of the present invention shown in FIG. 1 will be described in detail below with reference to the flowchart shown in FIG.
[0020]
Prior to the explanation of the operation, the rotation speed is obtained by calculation from the current and voltage of the permanent magnet type synchronous motor used as the drive motor in the suspended centrifuge of the present invention, and the operation, monitoring and measurement of the good rotation speed are obtained. Is possible.
In other words, since a permanent magnet is embedded in the rotor, which is a feature of the permanent magnet type synchronous motor, the internal rotational speed detection function can be used, so an external rotational speed detection mechanism that has been conventionally required, such as a pulse generator. Is no longer necessary. In addition, since synchronous motors have the same output frequency and rotational speed based on their operating principles, they can be rotated twice by using two types of rotational speed signals calculated from the output frequency and magnetic pole position. Speed anomalies can be monitored, making it more reliable than ever.
[0021]
In the flowchart shown in FIG. 2, first, the magnetomotive force is detected (S21), and the motor rotational speed is calculated by the above calculation (S22). Here, an overspeed check is performed (S23). Incidentally, the 105% overspeed always detects the magnetic pole position of the permanent magnet embedded in the rotor of the motor, and the built-in rotation speed signal calculated to the magnetic pole position. Is detected as an interlock. Further, the 110% overspeed is interlocked by monitoring the output frequency (S24).
Next, the deviation with respect to the target rotational speed is checked (S25). Here, according to the load inertia amount until the deviation amount of the target rotational speed of the motor reaches a first set value, for example, 3%, the feedforward control by the feedforward control unit 12 and the variable PI control unit 11 Lead compensation control is performed in accordance with a combination of variable PI control and equivalent disturbance compensation control by the equivalent disturbance compensation control unit 13 (S26). On the other hand, when the deviation amount of the target rotation speed is within the first set value, for example, within 3%, the system inertia amount automatic compensation function generation unit 14 sets a fixed P gain for the variable PI control unit 11. Then, an integration time constant is given, and classic fixed PI control is performed (S27). In other states, a range of P gain 7.5 to 30 and integration time constant of 67 ms to 179 ms is set according to the load inertia amount, and variable PI control is performed.
[0022]
In parallel with the check in S25, a deviation check for the maximum rotation speed is also performed (S28). Here, the lead compensation control according to the load inertia amount is used until the maximum rotation speed of the motor reaches a second set value, for example, 25% (S26), and when it is 25% or less, the third of the rated inertia amount is used. The system inertia amount automatic compensation function generation unit 14 generates a function for decreasing continuously or stepwise until a set value, for example, about 10%, and feedforward control by the feedforward control unit 12 Then, the advance compensation control according to the combination of the variable PI control by the variable PI control unit 11 and the equivalent disturbance compensation control by the equivalent disturbance compensation control unit 13 is performed (S29).
[0023]
As described above, according to the present invention, since a suspended centrifuge with a large amount of inertial energy is stable in operation, a control method with a fast response is not necessary, and a classical deviation is achieved at a stage where the deviation is about 3%. Even when switching to a fixed PI control, an appropriate control constant is set to enable safe driving over the entire area.
In addition, in a low speed range where the rotational speed is 25% or less, a derivative effect that can suppress the generation of abnormal noise from the flexible coupling part by setting and controlling the system inertia amount so that the load inertia amount is apparently reduced. Also occurs.
[0024]
FIG. 3 shows data (20 ms / div) of a rotational speed control curve when a suspended centrifuge is controlled by applying a permanent magnet type synchronous motor.
According to this, it can be seen that by setting a control constant for appropriate rotational speed control, the set rotational speed can be reached smoothly without overshoot or undershoot. That is, the overshoot width at the maximum rotation speed is 16.4 rpm, approximately 1.13% (maximum rotation speed: 1,450 rpm) in the case of the conventional pulse generator shown in FIG. According to the embodiment of the present invention, it is 16.5 rpm, about 1.13%, and there is almost no difference in the amount of chute. As shown in FIG. 5 (embodiment of the present invention) and FIG. 6 (conventional example), the same result was obtained in the control to the minimum rotational speed.
[0025]
From these results, it was confirmed that the same controllability as in the case of the conventional vector control system with a rotation speed detection sensor can be secured in the present invention.
The reason is that the amount of inertia energy peculiar to the centrifuge is considerably large and stable, so that the control method with fast response is switched to the PI control method which is a classic control method when the deviation is about 3%. Thus, control constants (proportional constants 30 to 7.5, integral time constants in the range of 67 ms to 179 ms) for appropriate rotation speed control are set.
In addition, when determining the method of rotational speed control, the classic PI control that was previously adopted for inverters was added with a rotational speed minor differential to slow down the response, while advance compensation control according to the load inertia amount. The method is adopted. That is, up to 97% of the target rotational speed is a control system in which advance compensation according to the load inertia amount is added to the rotational speed setting change (control system feedforward control with a transfer function of 1 as a whole, variable If the deviation of the rotation speed is within 3% using a combination of PI control and equivalent disturbance control method), the proportional amount (P operation) by the PI control method is reduced, and the rotation speed detection filter time (I operation) ) Is set to be long and controllability is reduced for both P and I, and control is performed so as to reach the target rotational speed in an optimum time.
[0026]
In addition, the inertia energy of the motor rotor itself is much smaller than that of the rotating drum that is the load, and the coupling between the motor and the load is a flexible coupling. Although there was concern about the occurrence of a resonance phenomenon, abnormal noise was generated from the flexible coupling by controlling the system inertia amount to be small so that the load inertia amount in the low speed range of 25% or less is apparently reduced. Could be prevented.
[0027]
As described above, the present invention applies a permanent magnet synchronous motor to a suspended centrifuge and adopts a novel drive control method in order to adapt the characteristics of the motor to the suspended centrifuge. Accordingly, the present invention provides a suspended centrifuge and a motor drive control method for the suspended centrifuge that can reduce overshoot and undershoot and eliminate the need for regular maintenance.
1 is executed by each of the variable PI control unit 11, the feedforward control unit 12, the equivalent disturbance compensation control unit 13, and the system inertia amount automatic compensation function generation unit 14 included in the motor drive control unit 1 shown in FIG. The motor drive control method in the suspended centrifuge of the present invention is realized by recording the procedure on a computer-readable recording medium, causing the computer system to read and execute the program recorded on the recording medium. Shall. The computer system here includes an OS and hardware such as peripheral devices.
[0028]
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.
[0029]
The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes a design and the like within a scope not departing from the gist of the present invention.
[0030]
【The invention's effect】
As described above, according to the present invention, the permanent magnet type synchronous motor incorporating the rotational speed detection mechanism is applied to the suspended centrifugal separator of the present invention, and double rotational speed measurement based on the frequency and the rotational speed is performed. Based on the above, it is possible to improve reliability and perform new control using it, which makes it possible to maintain the response accuracy of the rotation speed control and eliminate the need for an externally connected rotation speed detection mechanism. The reliability of the centrifuge is improved, and regular maintenance is not required, so that the maintenance cost can be reduced.
[0031]
In addition, according to the present invention, the characteristics of a motor capable of power regeneration that repeatedly starts and accelerates and decelerates a rotating drum having a large inertial energy within a short cycle can be adapted to the centrifuge, and overshoot and undershoot It is possible to provide a suspended centrifuge that is reduced and can realize stable operation. Furthermore, a derivative effect is also obtained that enables control of the generation of abnormal noise by flexible coupling due to torque ripple in a low speed range.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a motor drive control unit of a suspended centrifuge according to the present invention.
FIG. 2 is a flowchart cited for explaining the operation of the embodiment of the present invention.
FIG. 3 is a graph showing data of a rotation speed control curve when a suspended centrifuge is controlled by applying a permanent magnet type synchronous motor (overshoot).
FIG. 4 is a graph showing data of a rotational speed control curve when a conventional suspended centrifuge is controlled (overshoot).
FIG. 5 is a graph showing data of a rotation speed control curve when a suspended centrifuge is controlled by applying a permanent magnet type synchronous motor (undershoot).
FIG. 6 is a graph showing data of a rotational speed control curve when controlling a conventional suspended centrifuge (undershoot).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Motor drive control part, 2 ... Parameter setting part, 3 ... Control object, 11 ... Variable PI control part, 12 ... Feedforward control part, 13 ... Equivalent disturbance compensation control part, 14 ... System inertia amount automatic compensation function generation part

Claims (8)

A suspended centrifuge in which a rotating drum is coupled to a motor via a flexible coupling,
Lead compensation control by a combination of feedforward control, variable PI control and equivalent disturbance compensation control is performed according to the load inertia amount until the deviation amount of the target rotational speed of the motor reaches a first set value, and the target rotation A motor drive control unit that performs fixed PI control when the speed deviation amount reaches the first set value;
The motor drive controller is
The advance compensation control according to the load inertia amount is used until the deviation amount of the rotation speed of the motor reaches the second set value, and the third set value of the rated inertia amount is set below the second set value. A system inertia amount automatic compensation function generation unit that generates a function for sequentially decreasing until
A suspended centrifuge characterized by comprising: A permanent magnet synchronous motor to the motor, performs the rotational speed calculated using the magnetomotive force of the permanent magnet embedded in a rotor, according to claim 1, wherein the notifying to the motor drive control unit A suspended centrifuge. The motor drive controller is
A variable PI control unit that stabilizes the operation by applying a transfer function composed of a proportional gain and an integral gain to the motor as a deviation between a setting input that is input as an instruction value for the motor and a state quantity of the motor. The suspended centrifugal separator according to claim 1, wherein: The motor drive controller is
The setting input and state quantity difference the suspended lower centrifuge according to claim 1, characterized in that it has a feedforward control unit that maintains zero. The motor drive controller is
Load inertia weight which affects the driving characteristics of the motor, and suspended under centrifuge according to claim 1, characterized by having an equivalent disturbance compensation control unit to reduce the influence of the parameter change. A suspended centrifuge in which a rotating drum is coupled to a motor via a flexible coupling,
Lead compensation control by a combination of feedforward control, variable PI control and equivalent disturbance compensation control is performed according to the load inertia amount until the deviation amount of the target rotational speed of the motor reaches a first set value, and the target rotation A motor drive control unit that performs fixed PI control when the speed deviation amount reaches the first set value;
A suspension type centrifugal separator characterized in that a permanent magnet type synchronous motor is used as the motor, the rotational speed is calculated using the magnetomotive force of the permanent magnet embedded in the rotor, and the motor drive control unit is notified. Machine. A motor drive control method in a suspended centrifuge in which a rotating drum is coupled to a motor via a flexible coupling,
Lead compensation control by a combination of feedforward control, variable PI control and equivalent disturbance compensation control is performed according to the load inertia amount until the deviation amount of the target rotational speed of the motor reaches a first set value, and the target rotation There line fixed PI control when the deviation of the velocity becomes the first set value,
The advance compensation control according to the load inertia amount is used until the deviation amount of the rotation speed of the motor reaches the second set value, and the third set value of the rated inertia amount is set below the second set value. Generate a function to reduce sequentially until
A motor driving method in a suspended centrifugal separator. A motor drive control method in a suspended centrifuge in which a rotating drum is coupled to a motor via a flexible coupling,
Lead compensation control by a combination of feedforward control, variable PI control and equivalent disturbance compensation control is performed according to the load inertia amount until the deviation amount of the target rotational speed of the motor reaches a first set value, and the target rotation There line fixed PI control when the deviation of the velocity becomes the first set value,
A suspension type centrifugal separator characterized in that a permanent magnet type synchronous motor is used as the motor, the rotational speed is calculated using the magnetomotive force of the permanent magnet embedded in the rotor, and the motor drive control unit is notified. Motor drive method in the machine.

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