JP2010031679A - Pump system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently maximally use electric power from an electric power supply means when simultaneously driving a plurality of turbo-molecular pumps. <P>SOLUTION: A pump system includes: the plurality of turbo-molecular pumps T1-T4 driven by the electric power from the electric power supply means 1; an electric energy acquisition means 6 determining the overall electric power consumption Wt consumed by the plurality of turbo-molecular pumps T1-T4; and an electric power control means 4 controlling electric power supply to the turbo-molecular pumps T1-T4 so that the overall electric power consumption Wt determined by the electric energy acquisition means 6 does not exceed a predetermined set value Ws. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pump system having a plurality of turbomolecular pumps.

  In general, a plurality of turbo molecular pumps are used in a semiconductor device or the like. There is known a pump system that suppresses the maximum power consumption at the time of startup to a predetermined value or less by shifting the startup start times of the plurality of turbo molecular pumps from each other or extending the startup operation time (for example, Patent Document 1).

JP 2003-28072 A

  However, the system described in Patent Document 1 sets a power consumption pattern in advance and controls the driving of the pump in accordance with this pattern, and cannot efficiently use the power efficiently.

  A pump system according to the present invention includes a plurality of turbo molecular pumps driven by power from a power supply unit, a power amount acquisition unit for obtaining a total power consumption consumed by the plurality of turbo molecular pumps, and a power amount acquisition unit. And a power control means for controlling the power supplied to each turbomolecular pump so that the total power consumption thus obtained does not exceed a predetermined set value.

  According to the present invention, since the power supplied to the turbo molecular pump is controlled so that the total power consumption does not exceed the set value, the power from the power supply device can be efficiently and maximally used.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a configuration of a pump system according to an embodiment of the present invention. In the following, a case where four turbo molecular pumps are used will be described. The turbo molecular pump is, for example, a vacuum pump used in a semiconductor manufacturing apparatus, and each pump body T1 to T4 is connected to a plurality of vacuum chambers of a semiconductor manufacturing apparatus (not shown).

  Controllers C1 to C4 (control units) are connected to the pump bodies T1 to T4, respectively, and the driving of the pump bodies T1 to T4 is controlled by signals from the controllers C1 to C4. The power supply unit 1 is connected to the controllers C1 to C4, and the supply of power from the power supply unit 1 to the pump bodies T1 to T4 is controlled by signals from the controllers C1 to C4.

  Each of the controllers C1 to C4 is provided with a serial communication port SP, and the controllers C1 to C4 are connected by a communication line 2 through the serial communication port SP. That is, multidrop connection is used. As shown in the figure, ID numbers (1 to 4) are assigned to the controllers C1 to C4, and a PC (personal computer) 3 is connected to the controller C1 with ID = 1 via the communication line 2.

  FIG. 2 is a diagram illustrating an internal configuration of the controller C1. The configurations of the other controllers C2 to C4 are the same as those in FIG. The controller C1 includes a power conversion unit 40, a control unit 4, an input unit 5, and a power consumption calculation unit 6. In the pump body T1, there are provided a motor 7 for rotating a rotating shaft (not shown) of the rotor and a magnetic bearing 8 for supporting the rotating shaft of the rotor in a non-contact manner.

  The power conversion unit 40 converts AC power into DC power for motor driving and magnetic levitation. The control unit 4 includes a CPU, a ROM, a RAM, and the like, and outputs control signals to the motor 7 and the magnetic bearing 8 to control their driving, and between the controllers C2 to C4 and the PC 3. Control communication.

  The motor 7 is, for example, a DC brushless motor, and drives the rotor rotation shaft with a motor current supplied from the power supply unit 1. The position of the rotating shaft of the rotor is detected by a gap sensor. The magnetic bearing 8 is supplied with a magnetic bearing current from the power supply unit 1 based on the detected gap value, and the magnetic bearing 8 magnetically supports the rotor's rotating shaft.

  The input unit 5 is configured by, for example, an operation panel provided in front of the control unit, and inputs various setting values related to pump control for each pump body by a user operation. The serial communication port SP is provided on the back surface of the control unit, for example, and inputs / outputs signals related to pump power control.

  The power consumption calculation unit 6 calculates the power consumption of the pump body T1. FIG. 3A is a diagram showing the relationship between the motor current and the power consumption when the pump speed is constant, and FIG. 3B is the pump speed and the power consumption when the motor current is constant. It is a figure which shows the relationship. As shown in FIG. 3, the power consumption increases as the motor current increases and the pump speed increases. Based on this relationship, the power consumption calculator 6 calculates the power consumption corresponding to the motor current and the pump speed.

  In the present embodiment, among the plurality of controllers C1 to C4, the controller C1 is used as a master controller, and the controllers C2 to C3 are used as slave controllers. That is, the pump body T1 is controlled by a signal from the master controller C1, and the pump bodies T2 to T4 are controlled via the slave controllers C2 to C4. The PC 3 is used, for example, for monitoring the state of the pump bodies T1 to T4 and processing data.

  An alarm device 9 is connected to the PC 3. The alarm device 9 outputs a predetermined message to, for example, a display monitor, thereby notifying the user of a state in which the power supplied to the pump bodies T1 to T4 is limited as will be described later. The alarm device 9 can also be connected to the master controller C1.

  FIG. 4 is a flowchart illustrating an example of processing in the control unit 4 of the master controller C1. The process shown in this flowchart is started by turning on the power switch of the input unit 5, for example.

  In step S1, a power consumption confirmation command is transmitted to another controller Ck via the serial communication port SP. Note that k is a variable, and k = 2 is set in the initial state. In step S2, an operation state confirmation command is transmitted to the other controller Ck via the serial communication port SP. In step S3, it is determined whether or not k has reached 4, that is, whether or not the power consumption confirmation command and the operation state confirmation command have been transmitted to all the controllers C2 to C4. If step S3 is negative, the process proceeds to step S4, 1 is added to k, and the process returns to step S1. If step S3 is affirmed, the process proceeds to step S5.

  In step S5, the power consumption W2 to W4 and operation state signals of the pump bodies T2 to T4 transmitted from the controllers C2 to C4 by the process of FIG. At this time, the power consumption W1 of the pump body T1 calculated by the power consumption calculation unit 6 of the controller C1 is taken in at the same time, and the operating state of the pump body T1 is determined.

  In step S6, power consumption W1 to W4 of each pump body T1 to T4 is added to obtain a total value (total power consumption) Wt (= W1 + W2 + W3 + W4) of power consumption. Then, it is determined whether or not the total power consumption Wt is larger than a value (Ws−Wm) obtained by subtracting a predetermined margin Wm from a preset setting value Ws. The set value Ws is set in consideration of the power capacity of the power supply unit 1, and is set to be equal to the power capacity of the power supply unit 1, for example. This set value Ws can be changed by an operation at the input unit 5, and the same system can be used even in facilities having different power capacities of the power supply unit 1. The margin Wm is set so that the total power consumption Wt does not exceed the set value Ws after it exceeds the predetermined value Ws−Wm.

  When step S6 is affirmed, the process proceeds to step S7, and it is determined whether or not another controller Cn commands the acceleration operation or steady operation of the pump. Note that n is a variable, and n = 4 is set in the initial state. If step S7 is negative, that is, it is determined that the vehicle is decelerating, the process proceeds to step S8. In this case, the deceleration operation by this controller Cn is maintained and the operation state of another controller is determined. For this reason, in step S8, 1 is subtracted from n, the process returns to step S7, and the same processing is repeated.

  If step S7 is affirmed, the process proceeds to step S9, where a free-run command is transmitted to the controller Cn via the serial communication port SP and a free-run transmission flag is turned on. The free run command is a command for shutting off the power supply to the motor 7 and causing the pump to free run, thereby reducing the power consumption of the entire system. After transmitting the free-run command, the process waits for a predetermined time before proceeding to step S10. In step S10, the ID number n at this time is stored in the memory, and the process returns to step S1.

  On the other hand, if step S6 is negative, the process proceeds to step S11, and it is determined whether or not the free-run transmission flag is on, that is, whether or not any of the pumps T1 to T4 is free-running. If step S11 is affirmed, it will progress to step S12, and if it is denied, it will return to step S1. In step S12, an acceleration request command is transmitted to the controller Cn having the ID number n stored in step S10. After transmitting the acceleration request command, the process proceeds to step S13 after waiting for a predetermined time. In step S13, the free run flag is turned off, and the process returns to step S1.

  FIG. 5 is a flowchart illustrating an example of processing in each control unit 4 of the slave controllers C2 to C4. The process shown in this flowchart is started by turning on the power switch of the input unit 5, for example.

  In step S51, it is determined whether a power consumption confirmation command (step S1) has been received from the controller C1. If step S51 is affirmed, the process proceeds to step S52, and the power consumption W2 to W4 of each pump body T2 to T4 calculated by the power consumption calculation unit 6 is transmitted to the controller C1 via the serial communication port SP.

  In step S53, it is determined whether or not an operation state confirmation command (step S2) has been received from the controller C1. If step S53 is affirmed, the process proceeds to step S54 to determine whether the pump bodies T2 to T4 are in acceleration, deceleration, or steady state, and this operation state is transmitted to the controller C1 via the serial communication port SP. .

  In step S55, it is determined whether a free-run command (step S9) is received from the controller C1. When step S55 is affirmed, the process proceeds to step S56, the supply of drive current to the motor 7 is cut off, and the motor drive is turned off. As a result, the rotor rotates due to the inertial force and enters a free-run (free-rotation) state.

  In step S57, it is determined whether or not an acceleration request command (step S12) is transmitted from the controller C1. When step S57 is affirmed, the process proceeds to step S58, where the drive current is supplied again to the motor 7 to accelerate the rotation of the rotor.

The main operation of this embodiment will be described.
(1) At startup FIG. 6 is a diagram illustrating an example of operation characteristics at the time of pump activation. In the figure, the characteristic f1 is the characteristic of the rotational speed of the pump bodies T1 to T3, the characteristic f2 is the characteristic of the rotational speed of the pump body T4, and the characteristic f3 is the total power consumption Wt (total power consumption) of the pump bodies T1 to T4. (Quantity) characteristics.

  For example, when a start switch provided in the PC 3 is turned on, a motor current flows simultaneously to the motors 7 of the pump bodies T1 to T4, and the pump bodies T1 to T4 start to start simultaneously. Thereby, as shown in FIG. 6, the rotational speed of each pump body T1 to T4 gradually increases toward the rated rotational speed Na, and the total power consumption Wt also increases accordingly.

  When the total power consumption Wt exceeds the predetermined value Ws−Wm at time t1, a free-run command is transmitted to the pump driving controller C4 having the lowest priority (step S9). By transmitting this free-run command, the pump body T4 is free-run (step S56), and the increase in the rotational speed of the pump body T4 is stopped as indicated by the characteristic f2. At this time, the motor current decreases due to the free run of the pump body t4, but thereafter, the motor current increases due to the acceleration of the pump bodies T1 to T3. If the total power consumption Wt exceeds the predetermined value Ws−Wm again, the pump body T3 having the next lowest priority is free-runned. As a result, the maximum value of the total power consumption Wt can be made equal to or less than the set value Ws. In this case, the alarm device 9 is activated, and the user can recognize the motor current limit state.

  When the rotation speed of the pump bodies T1 to T3 reaches the rated rotation speed Na, the amount of motor current supplied to the pump bodies T1 to T3 decreases. Thereafter, when the total power consumption Wt becomes equal to or less than the predetermined value Ws−Wm at time t2, an acceleration request command is transmitted to the controller C4 that controls the pump drive during the free run (step S12). As a result, the pump body T4 is accelerated (step S58), and the pump rotational speed rises to the rated rotational speed Na as shown by the characteristic f2.

(2) Steady state FIG. 7 is a diagram illustrating an example of operation characteristics during steady operation. In the figure, the characteristic g1 indicates the characteristic of the rotational speed of the pump body T4, the characteristic g2 indicates the characteristic of the total electricity consumption Wt, and the characteristic g3 indicates the characteristic of the gas flow rate.

  In the state where the pump bodies T1 to T4 are rotating at the rated speed, when the gas flow rate increases at time t11, the load acting on the pump bodies T1 to T4 increases, and the total power consumption Wt increases. When the total power consumption Wt exceeds the predetermined value Ws−Wm, a free-run command is transmitted to the pump driving controller C4 having a low priority (step S9). As a result, the pump body T4 is free-runned, the pump rotational speed is decreased, the total power consumption Wt is decreased, and the maximum value of the total power consumption Wt is suppressed to be equal to or less than the set value Ws. In this case, the alarm device 9 is activated, and the user can recognize the motor current limit state.

  When the total power consumption Wt becomes equal to or less than the predetermined value Ws−Wm at time t12, an acceleration request command is transmitted to the controller C4 (step S12). Thereby, the supply amount of the motor current to the pump body T4 increases, and the total power consumption Wt increases. In this case, the motor current is supplied to the pump body T4 so as to keep the pump speed constant, instead of immediately increasing the speed of the pump body T4 to the rated speed Na.

  When the total power consumption Wt again exceeds the predetermined value Ws−Wm at time t13, a free-run command is transmitted to the controller C4. As a result, the pump body T4 is free-runned, the pump rotation speed is reduced, and the total power consumption wt is reduced.

  When the total power consumption Wt becomes equal to or less than the predetermined value Ws−Wm at time t14, an acceleration request command is transmitted to the controller C4. As a result, the amount of motor current supplied to the pump body T4 increases, and the pump speed is maintained. If the total power consumption Wt exceeds the predetermined value Ws−Wm at time t14, the free-run command is sent to the controller C3 with the next lowest priority while the free-run command is transmitted to the controller C4. Is sent.

  From time t14 to time t15, the transmission of the free run command and the transmission of the acceleration request command are repeated using the predetermined value Ws−Wm as a threshold value so that the total power consumption Wt does not exceed the set value Ws. When the gas flow rate decreases at time t15, the load acting on the pump bodies T1 to T4 decreases, and the total power consumption Wt decreases. When the total power consumption Wt becomes equal to or less than the predetermined value Ws−Wm at time t16, an acceleration request command is transmitted to the controller C4, and the motor current amount to the pump body T4 increases. As a result, the pump rotational speed increases, and the pump rotational speed reaches the rated rotational speed Na at time t17.

According to the present embodiment, the following operational effects can be achieved.
(1) The power consumption calculation unit 6 obtains the power consumption of each pump body T1 to T4, and when the total value Wt of these power consumptions exceeds a predetermined value Ws-Wm, The supply of motor current was cut off. That is, the motor current is not limited until the total power consumption Wt exceeds the predetermined value Ws−Wm, and the minimum necessary motor current is limited when the total power consumption Wt exceeds the predetermined value Ws−Wm. Thereby, the electric power from the electric power supply part 1 can be utilized efficiently and maximally, and the rotation speed of several pump main bodies T1-T4 can be raised to rated rotation speed Na in a short time at the time of pump starting. On the other hand, for example, a power consumption pattern at startup is set in advance and the drive of the pump body is controlled according to this pattern, even if there is a margin in power capacity, it cannot be used. The capacity cannot be fully utilized.

(2) Since the motor current is limited on the condition that the total power consumption Wt exceeds the predetermined value Ws−Wm, the power capacity of the power supply unit 1 is used to the maximum not only during startup but also during rated steady operation. be able to.
(3) When the total power consumption Wt exceeds the predetermined value Ws−Wm, the pump main body T4 having a low priority is free-runned to limit the supply power. Is maintained, and the power limit amount can be minimized.
(4) Since the set value Ws can be changed by the user's operation, the same system can be used even in facilities having different power capacities.

(5) Since the alarm device 9 notifies that the motor current is limited, the user can recognize the motor current limit state, and all pump bodies do not operate immediately at the start command. But the user is not confused.
(6) Since a plurality of pump driving controllers C1 to C4 are multidrop connected, wiring lines can be easily routed.
(7) Since the controller C1 is used as a master controller and the controllers C2 to C4 are used as slave controllers, the configuration can be simplified.

  In the above embodiment, the power consumption calculation unit 6 calculates the power consumption of each pump body T1 to T4 and adds this to obtain the total power consumption Wt, but the configuration of the power amount acquisition means is as follows. Not limited to this. When the total power consumption Wt exceeds the predetermined value Ws−Wm, the pump body T4 having a low priority is free-runned, but the supply power is controlled so that the total power consumption does not exceed the predetermined set value Ws. If it does, what kind of structure of the control part 4 as a power control means may be sufficient. Instead of cutting off the motor current, the supply amount of the motor current may be reduced. Although the pump bodies T1 to T4 are driven by the power from the power supply unit 1, any configuration of the power supply means may be used.

  Although the setting value Ws is changed by operating the input unit 5, the setting value changing means is not limited to this. Although the alarm device 9 notifies the user of the control state of the power control means, the notification means may have any configuration. The controllers C1 to C4 as a plurality of control units are multidrop connected via the serial communication port SP, but may be other connections. For example, the PC 3 and the controllers C1 to C4 may be connected via the communication line 2 respectively. Although the controller C1 is used as a master controller and the controllers C2 to C4 are used as slave controllers, the configuration of the controller is not limited to this.

  In the above embodiment, the four pump bodies T1 to T4 and the controllers C1 to C4 that control them are used. However, this is an example, and the number of turbo molecular pumps may be larger or smaller. That is, the present invention is not limited to the pump system of the embodiment as long as the features and functions of the present invention can be realized.

The figure which shows the structure of the pump system which concerns on embodiment of this invention. The figure which shows the internal structure of the controller of FIG. (A) is a figure which shows the relationship between motor current and power consumption when a pump rotation speed is made constant, (b) is a figure which shows the relationship between pump rotation speed and power consumption when motor current is made constant. The flowchart which shows an example of the process in the controller C1 of FIG. The flowchart which shows an example of the process in the controllers C2-C4 of FIG. The figure which shows an example of the operation characteristic at the time of starting which concerns on this Embodiment. The figure which shows an example of the operation characteristic at the time of the steady operation which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply part 4 Control part 5 Input part 6 Power consumption calculating part 9 Alarm apparatus T1-T4 Pump main body C1-C4 Controller

Claims (6)

A plurality of turbo molecular pumps driven by power from the power supply means;
A power amount obtaining means for obtaining a total power consumption amount consumed by the plurality of turbo molecular pumps;
A pump system comprising: power control means for controlling power supplied to each turbomolecular pump so that the total power consumption obtained by the power quantity obtaining means does not exceed a predetermined set value. The pump system according to claim 1,
Priorities are given to the plurality of turbo molecular pumps in advance,
When the total power consumption exceeds a predetermined value, the power control means limits the power supplied to the turbo molecular pump having a low priority. The pump system according to claim 1 or 2,
A pump system further comprising a set value changing means for changing the set value. The pump system according to any one of claims 1 to 3,
A pump system, further comprising notification means for notifying a user of a control state of the power control means. The pump system according to any one of claims 1 to 4,
The plurality of turbo molecular pumps are each provided with a control unit for controlling communication and controlling driving of each pump body,
These control units are multi-drop connected to each other. The pump system according to claim 5, wherein
The pump system according to claim 1, wherein the power control unit controls the power supplied to each pump body via the other control unit according to a signal from one control unit.

Images