Drive control device for variable vacuum capacitor

Abstract

A drive control device 10 for a variable vacuum capacitor 1 includes a motor 5, a resolver 6, and a control unit 8. The motor 5 drives a movable electrode of the variable vacuum capacitor 1. The resolver 6 detects the rotational position of the motor 5. The control unit 8 controls the rotation of the motor 5 on the basis of the rotational position detected by the resolver 6.

Description

Drive control device for vacuum variable capacitor

[0001] The present invention relates to a technology for increasing the speed of the control response of a vacuum variable capacitor applied to a high-frequency matching circuit of a thin-film manufacturing device for semiconductors or FPDs (flat panel displays).

[0002] In order to speed up the control response of the capacitance, a vacuum variable capacitor employs a ball screw drive system in which a ball screw is provided on the movable conductor and a rotating part is provided at the movable end of the vacuum container that is threadedly engaged with the ball screw and can rotate (Patent Document 1).

[0003] Patent No. 4449574

[0004] In recent years, with the increasing performance of thin film manufacturing equipment, there has been a growing need to quickly synchronize the commanded position and actual position of the movable electrode relative to the fixed electrode of the vacuum capacitor in order to arbitrarily control the capacitance of the vacuum variable capacitor at high speed.

[0005] To control the capacitance of the vacuum variable capacitor at higher speeds, it is necessary to increase the size of the motor that reciprocates the movable conductor. Furthermore, increasing the size of the motor increases the load on the driving components of the movable electrode, such as the ball screw and the movable conductor, which reduces the durability of the vacuum variable capacitor. Furthermore, increasing the speed of the motor can cause a phenomenon in which the command position and the actual position become out of synchronization (hereinafter referred to as "out-of-step phenomenon"), which can reduce the control response of the capacitance of the vacuum variable capacitor.

[0006] In view of the above circumstances, an object of the present invention is to speed up the control response of the capacitance of a vacuum variable capacitor and to extend the life of the vacuum capacitor.

[0007] Therefore, one aspect of the present invention is a vacuum variable capacitor that includes a motor that operates the movable electrode of the vacuum variable capacitor, a sensor that detects the rotational position of the motor, and a control unit that controls the rotation of the motor based on the rotational position detected by the sensor.

[0008] In one aspect of the present invention, in the drive control device for a vacuum variable capacitor, the sensor is a resolver.

[0009] In one aspect of the present invention, in the drive control device for a vacuum variable capacitor, the vacuum variable capacitor is a ball screw drive type vacuum variable capacitor.

[0010] In one aspect of the present invention, in the drive control device for a vacuum variable capacitor, the motor is a stepping motor having a maximum static torque of 1.0 Nm or less.

[0011] In one aspect of the present invention, in the drive control device for the vacuum variable capacitor, the motor is controlled at a rotational speed of 0 to 3300 rpm within an operating range of 0 to 10 rotations.

[0012] In one aspect of the present invention, the movable electrode takes 0.5 seconds or less to move from one end of the movable range of the movable electrode to the other end.

[0013] According to the present invention, the control response of the capacitance of the vacuum variable capacitor can be increased in speed, and the life of the vacuum capacitor can be extended.

[0014] 1 is a schematic diagram of a drive control device for a vacuum variable capacitor according to one embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of a coupling portion that connects the vacuum variable capacitor and a motor in FIG. 1. FIG. 3 is a performance test result of the rotational position control of the motor by the drive control device in FIG.

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] The drive control device 10 of the vacuum variable capacitor 1 of this embodiment shown in FIG. 1 includes an electrical connection part 2, a coupling part 3, a support plate 4, a motor 5, a resolver 6, a support plate 7, and a control part 8.

[0017] As the vacuum variable capacitor 1, for example, a ball screw driven vacuum variable capacitor disclosed in Patent Document 1 is applied.

[0018] The electrical connection portion 2 electrically connects the vacuum variable capacitor 1 to a main circuit (not shown).

[0019] As shown in Fig. 1, the coupling unit 3 is supported on the surface of the support plate 4 on the high-voltage side, and as shown in Fig. 2, it includes an insulating coupling 31 that connects the vacuum variable capacitor 1 and the motor 5, and an insulating housing 32 that stores the insulating coupling 31. The insulating coupling 31 transmits the driving force of the motor 5 to a movable conductor connected to a movable electrode in the vacuum variable capacitor 1. The insulating housing 32 stores the insulating coupling 31 while electrically insulating the vacuum variable capacitor 1 on the high-voltage side from the motor 5 on the low-voltage side.

[0020] The motor 5 is supported on the surface of the support plate 4 on the low-voltage side. The motor 5 drives the ball screw of the vacuum variable capacitor 1 via the insulating coupling 31 of the coupling unit 3 based on a control signal from the control unit 8 via the harness 51, thereby enabling the movable electrode to reciprocate along with the movable conductor of the vacuum variable capacitor 1. As the motor 5, for example, a stepping motor with a maximum static torque of 1.0 Nm or less is used.

[0021] The resolver 6 is a sensor that detects the rotational position of the motor 5 and outputs the detected position to the control unit 8 via a harness 61 .

[0022] The control unit 8 is supported by the support plate 7 attached to the high-voltage side of the support plate 4, and rotates the motor 5 based on a control signal from the terminal 11 to operate the movable conductor in the vacuum variable capacitor 1 and control the capacitance of the vacuum variable capacitor 1. The control unit 8 also controls the rotation of the motor 5 based on the rotational position of the motor 5 detected by the resolver 6, thereby preventing the motor 5 from losing synchronization.

[0023] An example of the operation of this embodiment will be described with reference to the same figure.

[0024] The control unit 8 receives a control signal for the motor 5 from the terminal 11 at regular time intervals (for example, every 1 ms). The motor 5 operates based on the control signal received from the control unit 8. Examples of the control signal include a position control command for controlling the rotational position of the motor 5 and a capacitance control command for controlling the capacitance formed between the fixed electrode and the movable electrode.

[0025] The motor 5 drives the ball screw of the vacuum variable capacitor 1 in response to the position control command or the capacitance control command from the control unit 8 to move the movable conductor.

[0026] The operation of the movable conductor in response to the position control command enables the desired positioning of the movable electrode relative to the fixed electrode. When the motor 5 is a stepping motor, for example, the position control unit is set so that the rotation of the motor 5 per count is 1 / 4000. The movable range of the movable electrode relative to the fixed electrode in the vacuum variable capacitor 1 is set so that the rotational position detected by the resolver 6 is 0 to 40,000 counts when the number of rotations of the motor 5 is 0 to 10. For example, when controlling the current position detected by the resolver 6 from 16,000 counts to the commanded position of 20,000 counts, the motor 5 is controlled to move from the fourth to fifth rotations. The operation of the movable electrode is controlled by the motor 5 so that the full stroke movement time of the vacuum variable capacitor 1 (the movement time from one end to the other end of the axial movable range of the movable electrode) is 0.5 seconds or less.

[0027] Furthermore, the desired capacitance formed between the fixed electrode and the movable electrode can be ensured by the operation of the movable conductor in response to the capacitance control command. For example, the capacitance can be arbitrarily controlled within a capacitance range corresponding to the rotation position of 0 to 40,000 counts commanded by the control unit.

[0028] Furthermore, depending on the application, the capacitance of the vacuum variable capacitor 1 needs to be controlled at high speed. When controlling the capacitance at high speed, the operation of the motor 5 needs to be controlled at high speed. According to the drive control device 10 of this embodiment, the rotation of the motor 5 is controlled based on the rotation position of the motor 5 detected by the resolver 6. This makes it possible to synchronize the rotation position of the motor 5 commanded from the control unit 8 (terminal 11) with the actual rotation position of the motor 5.

[0029] The operating state of the vacuum variable capacitor 1 due to the operation of the motor 5 (the rotational position and its control process, the capacitance and its control process) is sequentially transmitted to the terminal 11 via the control unit 8. If there is an abnormality in the vacuum variable capacitor 1 or the control unit 8, an alarm is transmitted to the terminal 11.

[0030] According to the drive control device 10 for the vacuum variable capacitor 1 described above, the rotation of the motor 5 is converted into linear motion by the drive component (ball screw), allowing the movable electrode within the vacuum variable capacitor 1 to move back and forth, and the capacitance formed by the fixed electrode and the movable electrode becomes variable.

[0031] In this case, even if the motor 5 is forced to undergo high load and high acceleration / deceleration when controlling the capacitance of the vacuum variable capacitor 1 at high speed, the desired capacitance can be quickly achieved without causing step-out by controlling the rotation of the motor 5 based on the rotation position detected by the resolver 6.

[0032] In particular, by using a stepping motor with a maximum static torque of 0.8 Nm or less as the motor 5, it is possible to reduce the size of the drive control device 10 while minimizing power consumption and avoiding step-out phenomena without increasing the size of the motor.

[0033] Furthermore, compared to a drive control device for a vacuum variable capacitor 1 that does not use a resolver 6 (for example, a drive control device for a vacuum variable capacitor 1 that uses an incremental encoder as a conventional position detection mechanism with low accuracy or large delay), control is possible at approximately 10 times the control speed, thereby achieving both faster capacitance control response and a longer life for the vacuum variable capacitor.

[0034] Figure 3 shows the results of a performance test of the rotational position control of the motor 5 using the drive control device 10. The figure shows the control completion time and maximum rotational speed for a motor 5 with a rated voltage of 24 V, a rated current of 1.7 A, a maximum input of 8.09 W, and a maximum static torque of 0.380 Nm, operating in a range of 0 to 10 rotations. It was confirmed that high-speed control was achieved, with a control completion time of 50 ms to 250 ms, position control of ±0.009 deg, and a maximum rotational speed of 3300 rpm. These results suggest that the motor 5 can be controlled at a rotational speed of 0 to 3300 rpm within a range of 0 to 10 rotations. Furthermore, it is also suggested that this control of the motor 5 can be used to control the operation of the movable electrode so that the full-stroke movement time is 0.5 seconds or less.

[0035] The vacuum variable capacitor applied to the present invention is not limited to a ball screw drive system, but can also be a feed screw drive system, as long as it has a movable conductor drive part (ball screw or feed screw) that can withstand the high-speed operation of the motor 5. Furthermore, the sensor applied to the present invention is not limited to a resolver, and position detection mechanisms other than a resolver can be applied, as long as it can detect the rotational position of the motor with high accuracy and low delay.

[0036] REFERENCE SIGNS LIST 1... Vacuum variable capacitor 2... Electrical connection portion 3... Coupling portion 31... Insulating coupling 32... Insulating housing 4, 7... Support plate 5... Motor 51... Harness 6... Resolver 61... Harness 8... Control unit 10... Drive control device 11... Terminal

Claims

1. A drive control device for a variable vacuum capacitor, comprising: a motor that drives a movable electrode of the variable vacuum capacitor; a sensor that detects the rotational position of the motor; and a control unit that controls the rotation of the motor based on the rotational position detected by the sensor. The drive control device for a variable vacuum capacitor is characterized by comprising the above components.

2. The drive control device for a variable vacuum capacitor according to claim 1, wherein the sensor is a resolver.

3. The drive control device for a variable vacuum capacitor according to claim 1, wherein the variable vacuum capacitor is a variable vacuum capacitor of a ball screw drive type.

4. The drive control device for a variable vacuum capacitor according to claim 1, wherein the motor is a stepping motor having a maximum static torque of 1.0 Nm or less.

5. The drive control device for a variable vacuum capacitor according to claim 1, wherein the motor is controlled at a rotational speed of 0 to 3300 rpm in an operating range of 0 to 10 rotations.

6. The drive control device for a variable vacuum capacitor according to claim 1, wherein the movable electrode has a movement time of 0.5 seconds or less from one end to the other end of the movable range of the movable electrode.

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