JPH0114775Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a cryopump operation device that condenses and adsorbs gas molecules on a surface cooled to an ultra-low temperature and exhausts the gas molecules.

(Prior Art) The present applicant previously developed a cryopump consisting of a refrigerator and a compressor that supplies compressed gas to the cryopump, in which the refrigerator was connected to an AC power source using a frequency converter. An operating device has been proposed in which the compressor is operated with a high frequency voltage and the compressor is operated with a low frequency voltage of the AC power source.

According to this device, the refrigeration function, that is, the pump performance of the cryopump, does not decrease much compared to a device that operates the refrigerator and compressor at a voltage with a higher frequency than the AC power supply, and the frequency converter is able to operate at a higher frequency than the AC power source. It is economical and easy to install because it can be small enough to fit a small refrigerator.

(Problems to be solved by the invention) In the above operating device, a synchronous motor is used as the drive motor of the refrigerator, and as a power source for the synchronous motor,
A PWM or PAM frequency converter with a filter connected to the output side to output a sine wave voltage was used. However, the capacitor of the filter is prone to failure due to harmonic components of the output of the frequency converter, and the cost is high because a filter must be added to convert the output waveform into a sine wave.

The present invention aims to solve these problems.

(Means for solving the problem) The present invention connects a synchronous motor that drives a cryopump refrigerator to a frequency converter connected to an AC power supply, and provides a compressor that supplies compressed gas to the refrigerator. In a device that connects a driving motor of a machine to the AC power supply, the frequency converter is composed of a reference signal generation circuit that outputs a sine wave signal of a desired frequency, and an amplifier circuit that amplifies the sine wave signal. It is characterized by

(Example) In FIG. 1, 1 is a cryopump, and the cryopump 1 is designed to form an ultra-low temperature cooling surface.
It includes a refrigerator 2 and a compressor 3 that supplies compressed gas to the refrigerator 2. The refrigerator 2 is composed of two stages of refrigeration cylinders 5a and 5b provided in a pump case 4, and a drive device 6 provided outside the pump case 4 and consisting of a synchronous motor with a rating of 100W, for example. When the pistons in the cylinders 5a and 5b are reciprocated, gas such as helium gas circulating between the compressor 3 and the compressor 3 via the flexible hose 7 expands adiabatically within the cylinders 5a and 5b.
The shield 8, buffer 9, and cryopanel 10 attached to each cylinder become extremely low temperature and act to condense and adsorb gas molecules and exhaust them. Compressor 3 drives this, for example, 5KW
It is equipped with a drive device 11 consisting of a motor with a rating of use. A frequency converter 13 connected to a power source 12 having a frequency of, for example, 50 Hz is connected to the synchronous motor as the drive device 6 of the refrigerator 2.

The frequency converter 13 has a circuit configuration as shown in the second diagram. That is, for example, a reference signal generation circuit 14 that outputs a 60Hz sine wave signal, and the circuit 14
a power amplifier circuit 17 that amplifies the sine wave signal of via the error amplifier circuit 15 and the FET drive circuit 16;
and an input transformer 1 connected to a 50Hz power supply, for example
8. It is composed of a power supply circuit 21 for the power amplifier circuit 17, which is composed of a rectifier circuit 19 and a smoothing capacitor 20, and an output transformer 22.

The reference signal generation circuit 14 converts, for example, a 60Hz square wave obtained from an oscillator into a triangular wave using an integrator circuit, crushes the peak of this triangular wave using a Zener diode, and resonates at 60Hz. By passing the signal through a low-pass filter, a 60Hz sine wave signal with low distortion is obtained.

The frequency converter 13 operates as follows.

The 50 Hz AC voltage applied to the input terminal 23 is transformed by the input transformer 18, rectified by the rectifier circuit 19, and supplied to the power amplifier circuit 17. This power amplifier circuit 17 is supplied with a 60 Hz signal from the reference signal generating circuit 14 via the FET drive circuit 16 and the error amplifier circuit 15.
A sine wave signal is supplied, and the power amplified sine wave signal is transformed to a desired voltage by an output transformer 22 and outputted from an output terminal 24. The output voltage obtained by the output transformer 22 is transmitted to the error amplifier circuit 15.
The signal is fed back to the reference signal generating circuit 14, where it is compared with the sine wave signal output from the reference signal generating circuit 14. This error amplification circuit 15 functions to stabilize output voltage fluctuations due to load fluctuations, input fluctuations, etc. to a constant level.

In FIG. 2, reference numeral 25 denotes an inrush current prevention circuit that prevents inrush current from flowing into the smoothing capacitor 20 and deteriorating or damaging the rectifier when the power is turned on.

Thus, according to the operating device of the present invention, when a 60Hz frequency converter is used in a 50Hz area, the same refrigeration capacity as when a cryopump is used in a 60Hz area can be obtained. Also, in a 60Hz area, for example, 72Hz
The refrigeration capacity of the cryopump can be slightly improved by using a frequency converter.

(Effects of the invention) As described above, according to the invention, the frequency converter consists of a reference signal generation circuit that outputs a sine wave signal of a desired frequency and an amplifier circuit that amplifies the sine wave signal, and the output side Since there is no need to provide a filter to make the output a sine wave, it is possible to prevent troubles due to failure of the filter, and there are also effects such as lower costs.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a cryopump operating device, and FIG. 2 is a block diagram of an example of a frequency converter used in the cryopump operating device of the present invention. 1... Cryopump, 2... Freezer, 3...
Compressor, 6... Drive device consisting of a synchronous motor, 1
DESCRIPTION OF SYMBOLS 1... Drive device, 12... Power supply, 13... Frequency converter, 14... Reference signal generation circuit, 15... Error amplifier circuit, 17... Power amplifier circuit.

Claims (1)

[Scope of utility model registration request] A synchronous motor that drives a cryopump refrigerator is connected to a frequency converter connected to an AC power source, and a motor for driving a compressor that supplies compressed gas to the refrigerator is connected to the AC power source. A cryopump operating device, wherein the frequency converter is comprised of a reference signal generation circuit that outputs a sine wave signal of a desired frequency, and an amplifier circuit that amplifies the sine wave signal.