JP3196095B2 - Turbo molecular pump drive power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive power supply for a turbo molecular pump using an inverter.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing an example of a block configuration of a conventional turbo molecular pump drive power supply device. As shown in the figure, a conventional turbo molecular pump drive power supply is provided with an inverter 10.
PWM controller 21, voltage control circuit 22, D / A conversion circuit 23, up / down counter 24, voltage detection circuit 2
5. It comprises a current detection circuit 26, an alarm circuit 27, and a start / stop unit 30.

The inverter 10 includes a transformer 11, a current controller 12 including a switching element 12-1 and a resistor 12-2, rectifiers 13-1 and 13-2, and a reactor 13-.
3, a rectifier 13 including a capacitor 13-4, a resistor 14 for detecting an output current, and a switching element 15-1.
The output control unit 15 supplies driving power to the turbo molecular pump 40.

[0004] The primary side of a transformer 11 of the inverter 10 is connected in series with a current control unit 12 and is connected to an AC power supply via a rectifier diode. The secondary voltage of the transformer 11 is converted into a DC voltage by the rectifier 13 and supplied to the output controller 15. The output control unit 15 converts the DC voltage into a high-frequency three-phase AC, and supplies a driving power to the turbo molecular pump 40. A resistor 14 for detecting a current is inserted into a negative connection line between the rectifier 13 and the output controller 15, one of which is connected to the ground and the other to the current detection circuit 26.
Is connected to the voltage detection circuit 25.

The current control unit 12 is controlled by an output signal of a PWM controller 21 driven by a voltage control circuit 22. The voltage detection circuit 25 detects the output of the rectifier 13 and outputs a detection signal to the voltage control circuit 22. The current detection circuit 26 detects the load current and outputs the detection signal to the alarm circuit 27. The up / down counter 24 counts the pulses of the clock signal according to the start signal from the start / stop unit 30 and outputs the count value to the D / A conversion circuit 23. D /
The A conversion circuit 23 converts the count value into an analog voltage value corresponding to the count value and outputs the analog voltage value to the voltage control circuit 22.

When the start / stop unit 30 is started, the up / down counter 24 counts up the clock signal in response to the start signal, and counts the count value to the D / A conversion circuit 2.
Output to 3. The D / A conversion circuit 23 inputs an analog voltage value to the voltage control circuit 22 according to the count value. The voltage control circuit 22 controls the energized section of the current control unit 12 through the PWM controller 21 while checking the voltage fed back from the voltage detection circuit 25, and controls the output voltage of the transformer 11. As a result, the output voltage of the rectifier 13 rises in accordance with the count value of the up / down counter 24, and the output controller 15 converts the rising output voltage into three-phase alternating current by the output controller 15, and It is supplied to the pump 40 and started.

After the start-up is completed, the voltage control circuit 22 controls the PWM controller 21 so that the voltage fed back from the voltage detection circuit 25 becomes constant, and the inverter output voltage V
At the rated voltage. When the inverter 10 is stopped, a stop signal is sent from the start / stop unit 30 to the up / down counter 24, and the countdown causes the inverter output frequency to decrease with the countdown and stop by regenerative braking.

[0008] In addition, a power supply device that outputs half the rated voltage when there is no load (or light load) according to the load of the pump is used as a power supply device.

[0009]

However, when a conventional power supply device that outputs a constant rated voltage is used, the reactive power increases when the turbo molecular pump 40 is not loaded, and
There is a problem that the temperature of the pump increases due to the heat of the resistance loss due to the reactive current. Further, when the turbo molecular pump 40 is not loaded (light load), the output voltage is set to 1 at the rated output.
When a power supply device of / 2 is used, there is a problem that the output voltage may be reduced to 1/2 or may be in an unstable state such as full output (rated output) depending on the load condition. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and eliminates the above-mentioned problems. Thus, the output voltage is continuously controlled by providing feedback on the load current and the actual rotation speed that change with the load. It is an object of the present invention to provide a turbo molecular pump drive power supply that supplies a stable voltage and current according to a load.

[0011]

In order to solve the above problems SUMMARY OF THE INVENTION The present invention has a voltage detecting means for detecting the inverter and the output voltage of the inverter, is fed back to the detection output voltage detected by said voltage detecting means In a turbo-molecular pump drive power supply device having a voltage control means for controlling an output voltage, a rotation speed detection means for detecting a rotation speed of the turbo-molecular pump, a current detection means for detecting a load current, and a set current value to the voltage control means . Adjustment means for feeding back the difference between the detected load current value and the difference between the rated rotation speed and the detected rotation speed of the turbo-molecular pump is provided, and the adjustment unit does not perform feedback for a certain period of time until completion of startup at startup, and after completion of startup. Feedback is performed to maintain the rotation speed of the turbo-molecular pump at the rated rotation speed, and the voltage control means
Difference between set current value and detected load current value or turbo molecular pump
The difference between the rated speed of the pump and the detected
If the load of the molecular pump gradually increases / decreases,
The output voltage of the converter is continuously increased / decreased to change the load.
The power factor is set to 1 with respect to motion .

[0012]

According to the present invention, the output signal of the current detection circuit 26 is input to the error amplifier 28, which compares the output signal with the set value and supplies the difference signal to the voltage control circuit 22 and the rotation speed detector 31. The actual speed signal obtained through the F / V conversion circuit 29 is compared with the rated speed, and the difference signal is supplied to the voltage control circuit 22. Therefore, as shown in FIG. 2, after the start-up is completed, if the load is light, the output voltage V is lowered (FIG. 2).
B) and f), when the load is large, the output voltage V is increased (d in FIG. 2). When the pump load gradually increases, the output voltage V increases along a straight line c. When the pump load gradually decreases, the output voltage V decreases along a straight line e. The output voltage V at the corresponding point P is output. Therefore, the unstable state unlike the related art is eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a block configuration of a turbo molecular pump drive power supply device of the present invention. As shown, the turbo molecular pump drive power supply of the present invention has an inverter 1.
0, PWM controller 21, voltage control circuit 22, D / A conversion circuit 23, up / down counter 24, voltage detection circuit 25, current detection circuit 26, alarm circuit 27, error amplifier 2
8, an F / V conversion circuit 29, a start / stop unit 30, and a rotation speed detector 31.

The inverter 10 includes a transformer 11, a current control unit 12 including a switching element 12-1 and a resistor 12-2, rectifying elements 13-1 and 13-2, and a reactor 13-.
A rectifier 13 comprising a capacitor 3 and a capacitor 13-4, a resistor 14 for detecting an output current, and an output controller 15 comprising a plurality of (six in the figure) switching elements 15-1. A drive power is supplied to the molecular pump 40.

The primary side of the transformer 11 is connected to a current controller 12
Is connected in series with the AC power supply via a rectifier diode. The secondary voltage of the transformer 11 is converted into a DC voltage by the rectifier 13, and the converted DC voltage is output to the output controller 1.
5 is supplied. The output control unit 15 controls the switching element 15-1 to be turned on and off by a control device (not shown). The on / off control of the switching element 15-1 reduces the DC voltage from the rectifying unit 13 by three. It is converted into a phase alternating current and supplied to a turbo molecular pump 40.
A resistor 14 for detecting a current is inserted into a negative connection line between the rectifier 13 and the output controller 15, one of which is connected to the earth and the other to the current detection circuit 26, and the output voltage of the rectifier 13 is Is connected to the voltage detection circuit 25.

The current control section 12 is controlled by an output signal of a PWM controller 21 driven by an output signal of a voltage control circuit 22. The voltage detection circuit 25 detects the output voltage of the rectifier 13 and outputs a detection signal to the voltage control circuit 22. The current detection circuit 26 detects the output current of the rectifier 13 from the voltage at the end of the resistor, and outputs a detection signal to the alarm circuit 27 and the error amplifier 28. The output signal of the F / V conversion circuit 29 and the output signal of the up / down counter 24 are input to the error amplifier 28.

A detection output of a rotation speed detector 31 for detecting the rotation speed of the turbo molecular pump 40 is input to the F / V conversion circuit 29, and the F / V conversion circuit 29 detects the rotation speed of the turbo molecular pump 40 by the rotation speed detector 31. The detected signal of the actual number of rotations is converted into a voltage value and output to the error amplifier 28. The error amplifier 28 compares the set value with the output current of the rectifier 13, supplies the difference signal to the voltage control circuit 22, and detects the actual rotation number of the turbo molecular pump 40 from the F / V conversion circuit 29. The difference is compared with the rated rotation speed of the turbo molecular pump 40, and the difference signal is supplied to the voltage control circuit 22.

The up / down counter 24 counts the clock signal based on the output signal of the start / stop unit 30 and outputs the count value to the D / A conversion circuit 23. The D / A conversion circuit 23 converts this count value into an analog voltage. The signal is converted into a signal and input to the voltage control circuit 22. Also, during a certain period of time when the start / stop unit 30 starts up, there is no output signal from the up / down counter 24 to the error amplifier 28, and the output of the error amplifier is stopped.

Next, the operation of the turbo molecular pump driving power supply device having the above configuration at the time of startup will be described. The up / down counter 24 counts up the clock signal for a predetermined time in response to a start output signal from the start / stop unit 30, and outputs the count value to the D / A conversion circuit 23. D / A conversion circuit 2
3 converts the count value into an analog voltage signal accordingly and outputs the analog voltage signal to the voltage control circuit 22. The voltage control circuit 22 controls the conduction section of the current control unit 12 through the PWM controller 21 while checking the analog voltage signal with the voltage detection signal from the voltage detection circuit 25, and controls the output voltage of the transformer 11.

As a result, the output voltage of the rectifier 13 increases as the count value of the up / down counter 24 increases,
This rising DC output voltage becomes 3
It is converted to a phase alternating current and the turbo molecular pump 40 is started. FIG. 2 is a diagram illustrating a DC output voltage characteristic of the rectifier 13. Up-down counter 2 within a certain time at the start
Since there is no output signal from 4 to the error amplifier 28 and the output of the error amplifier 28 is stopped, the inverter output voltage V, which is the output voltage of the rectifier 13 at the time of starting the power supply, follows the straight line a in FIG. To rise. During this time, the inverter 10 has V
It operates at VVF (variable voltage & variable frequency).

After a certain period of time, the value of the up / down counter 24 becomes a constant value, and at the same time, an output signal is output from the up / down counter 24 to the error amplifier 28, the error amplifier 28 operates, and the load from the current detection circuit 26 The current is fed back, and the actual rotation speed of the turbo molecular pump is input and compared with the rated rotation speed, and the difference is fed back to the voltage control circuit 22.

Next, the operation of the turbo molecular pump driving power supply during operation will be described. The inverter 10 is operated so as to output a rated frequency. When the load of the turbo molecular pump 40 is light, the reactive power increases and the current increases, so that the voltage control circuit 22 inverts the signal from the error amplifier 28.
The operation is performed so as to lower the output voltage V, and the voltage is increased / decreased as the load increases / decreases. Therefore, as shown in FIG. 2, after the startup is completed, if the load is light, the output voltage V of the rectification unit 13 is reduced (b, f in FIG. 2), and if the load is large, the output voltage V of the rectification unit 13 is increased. (D in FIG. 2).

When the pump load gradually increases, the output voltage V of the rectifier 13 rises along a straight line c. When the pump load gradually decreases, the output voltage V of the rectifier 13 rises along a straight line e. If the load is an intermediate load, the output voltage V of the rectifier 13 at the point P corresponding to the intermediate load is output. When the inverter 10 is stopped, a start / stop unit 30 sends a stop signal to the up / down counter 24 and counts down by the up / down counter 24, so that the inverter output frequency is reduced along with the countdown and regenerated. Stop by braking.

[0024]

As described above, according to the present invention, the following excellent effects can be expected. The adjustment means does not perform feedback for a certain period of time until the completion of startup at startup,
Feedback is performed after the start-up is completed, and the rotation speed of the turbo-molecular pump is maintained at the rated rotation speed, and the voltage control means determines the difference between the set current value and the detected load current value from the adjusting means or the rated rotation speed and the detected rotation speed of the turbo-molecular pump. When the load of the turbo-molecular pump gradually increases / decreases due to the increase / decrease of the difference of, the output voltage of the inverter is continuously increased / decreased,
Since the power factor is set to 1 with respect to the fluctuation of the load, the torque at the time of acceleration is ensured until the start of the start is completed ,
After completion, the output voltage of the inverter is continuously and stably controlled with respect to the fluctuation of the load, and the load current is minimized, that is, the power factor = 1.
And the temperature rise of the motor, the turbo-molecular pump and the rotor due to the reactive current can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a block configuration of a turbo molecular pump drive power supply device of the present invention.

FIG. 2 is a diagram showing output voltage characteristics of a turbo molecular pump drive power supply device of the present invention.

FIG. 3 is a diagram showing a block configuration example of a conventional turbo molecular pump drive power supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inverter 11 Transformer 12 Current control part 12-1 Switching element 12-2 Resistor 13 Rectification part 13-1 Rectifier 13-2 Rectifier 13-3 Reactor 13-4 Capacitor 14 Resistor 15 Output control part 15-1 Switching Element 21 PWM controller 22 Voltage control circuit 23 D / A conversion circuit 24 Up / down counter 25 Voltage detection circuit 26 Current detection circuit 27 Alarm circuit 28 Error amplifier 29 F / V conversion circuit 30 Start / stop device 31 Rotation speed detector 40 Turbo molecular pump

Continuation of the front page (56) References JP-A-58-175989 (JP, A) JP-A-53-74225 (JP, A) JP-A-56-107793 (JP, A) JP-A-2-215996 (JP) , A)

Claims (1)

(57) [Claims] 1. A includes an inverter and a voltage detecting means for detecting an output voltage of the inverter, a turbo molecular pump having a voltage control means for controlling the output voltage is fed back the detected detection output voltage at said voltage detecting means In the drive power supply device, a rotation speed detecting unit that detects a rotation speed of the turbo-molecular pump,
To the current detecting means for detecting the load current and the voltage controlling means
Adjustment means for feeding back the difference between the set current value and the detected load current value or the difference between the rated rotation number and the detected rotation number of the turbo-molecular pump is provided, and the adjustment means performs the feedback for a certain period of time until the completion of the start-up. After the start-up is completed, the feedback is performed, the rotation speed of the turbo-molecular pump is maintained at the rated rotation speed, and the voltage control means is connected to the front from the adjustment means.
The difference between the set current value and the detected load current value or the turbo
Due to the increase or decrease in the difference between the rated
As a result, the load of the turbo molecular pump gradually increases / decreases.
In this case, the output voltage of the inverter is continuously increased / decreased so that the power factor becomes 1 with respect to a change in load .