JP2003056926A - Troubleshooting method and troubleshooting apparatus for cryogenic refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a troubleshooting method for a cryogenic refrigerating machine comprising the steps of finding a refrigerating machine exhibiting a deteriorated refrigeration performance from among an enormous number of base stations, and executing maintenance and inspection in an early stage, and to provide a troubleshooting apparatus for the same. SOLUTION: The troubleshooting apparatus for the cryogenic refrigerating machine comprises a cold box 6, a cold stage 7a provided in the cold box 6, a cryogenic compressor 7c for cooling the cold stage 7a, circuit elements installed in the cold stage 7a, a sensor provided on an arbitrary one of the elements and having an arbitrary detecting function, and a controller 8 to which a detection signal of the sensor is inputted and which executes control for troubleshooting the cryogenic refrigerating machine 7 when the value of the input signal is judged to be abnormal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating machine failure repairing apparatus, and more particularly to a cryogenic refrigerating machine failure repairing apparatus used for cooling a circuit element of a base station for a mobile phone such as a superconducting filter.

[0002]

2. Description of the Related Art In recent years, as the number of mobile communications using mobile phones, PHSs (simple mobile phones) and the like has increased, the number of carriers has also increased. Therefore, measures for effectively using resources are being considered by narrowing the frequency band occupied by one line and narrowing the difference between the frequency regions occupied by communication carriers. However, in the situation where the filter is used up to now, if the difference for each frequency domain occupied by the communication carrier is narrowed, adjacent interference occurs in the adjacent frequency domain, which causes a problem. In order to solve this problem, a filter having a steep attenuation characteristic closer to a rectangular shape and a pass characteristic with less loss is required. Superconducting filters are known to be the only filters that can meet these requirements.

Since the surface resistance of a superconductor in the microwave band is lower than that of a normal conducting metal by one digit or more, when this superconductor is applied to a filter for a mobile communication base station, (1) a constant Q is obtained. The volume of the normal conducting device having a value (a quantity representing the sharpness of resonance and corresponding to the quality parameter of the device) is reduced to 1/100, and (2) the Q value of the superconducting device is usually constant in a device of a constant volume. It is attracting attention because it is 10 to 30 times as large as a conductive device. Since the refrigeration penalty can be greatly reduced in filters using high-temperature superconductors, the development is becoming more active along with the progress of small refrigerators.

In order to obtain the above-mentioned steep attenuation characteristics as desired, a highly accurate superconducting filter is required,
It requires a filter adjustment process at the manufacturing stage. This superconducting filter requires the maintenance and inspection of the cryogenic refrigerator required to maintain the desired characteristics at low temperatures.

Therefore, first, FIGS. 4 and 5 show which part of the communication circuit of the mobile phone the superconducting filter is used for.

FIG. 4 is a block diagram of a base station of a conventional receiving system. FIG. 5 is a schematic diagram illustrating a conventional example showing a relationship between a conventional base station and a mobile phone.

The mobile phone 1 enables communication with the other party by transmitting and receiving to and from the antenna 3 of the base station 2 installed on the roof of a steel tower or a building.

The antenna 3 is constructed as a duplexer for both reception and transmission. The reception wave received by the antenna 3 is processed by the reception system circuit of FIG.
The transmission wave transmitted from is processed by a transmission system circuit (not shown).

In the receiving system, interference can be effectively prevented by incorporating the superconducting filter into the receiving system immediately below the antenna, so that the antenna 3 is connected to the superconducting filter 4. This superconducting filter 4 has a low noise amplifier 5
Are connected to the reception signal processing system of the next stage. The received signal processing system is further connected to a telephone line.

The cold box 6 has a structure for blocking heat invasion from the outside by, for example, vacuum heat insulation, and has a cold stage 7a forming a part of the cryogenic refrigerator 7, a superconducting filter 4 which is a circuit element, and a low temperature. The noise amplifier 5 is housed, the vacuum insulation between the inside air and the outside air is maintained, and the cold stage 7a can be cooled at an extremely low temperature. Without the cold box 6, moisture in the atmosphere is condensed, and a large amount of heat enters the refrigerator due to heat conduction in the atmosphere, so that it is not cooled to an extremely low temperature.

The superconducting filter 4 and the low noise amplifier 5 enclosed in the cold box 6 are cooled by the cryogenic refrigerator 7 to an extremely low temperature such as liquid nitrogen temperature (77 K or less). Here, the cryogenic refrigerator 7 uses a heat exchange cycle by compression / expansion of helium gas or the like to maintain an extremely low temperature of 77K or less, a cryogenic compressor 7c, a connecting member 7b, a cold stage 7a and those. It is composed of piping for connecting. The cryogenic compressor 7c is operated so as to be cooled by a control device (not shown). Operation control system is feedback control system, feed-forward control system,
A fuzzy control method or the like can be appropriately selected. The inside of the cold box 6 is previously set by a vacuum pump (not shown),
After vacuum evacuation, it is hermetically sealed to maintain an ultrahigh vacuum.

As described above, by cooling the superconducting filter 4 and the low noise amplifier 5 to an extremely low temperature, the thermal noise generated in the superconducting filter 4 and the low noise amplifier 5 can be reduced to the utmost limit. As a result, the noise figure of the conventional high-sensitivity wireless receiver is significantly improved, and the reception sensitivity is significantly improved. Therefore, by using such a high-sensitivity radio receiver, it is possible to obtain a reception output of, for example, a prescribed C / N (carrier power / noise power) even for a low-level reception signal. Further, it is possible to obtain the effect that the transmission power on the transmission side required to obtain the specified C / N reception output is small.

Since the superconducting filter 4 and the low noise amplifier 5 for cryogenic temperatures can be adjusted easily and in a relatively short time by using liquid nitrogen, 77K
Many are designed to work with:

[0014]

6 to 10 show examples of various temperature characteristics of the low noise amplifier 5 and the superconducting filter 4 which are designed to operate at 77K in the conventional high sensitivity radio receiver. Show.

FIG. 6 shows a conventional high-sensitivity radio receiver 7
It is a figure which shows the temperature change of the amplifier gain and amplifier noise figure of the low noise amplifier of the receiving system which operate | moves at 7K. FIG. 7 is a diagram showing a temperature change of the insertion loss of the reception band filter at 77K in the conventional high sensitivity wireless receiver.

As shown in FIG. 6, the low noise amplifier 5 has a lower noise figure and a higher gain as the temperature decreases. Also, in the superconducting filter 4, as shown in FIG. 7, the insertion loss is reduced as the temperature becomes lower.

As described above, the circuit elements operating at extremely low temperatures are characterized in that their respective characteristics change with temperature.

Further, the superconducting filter 4 branches the radio wave received from the antenna 1 to the circuit of the signal processing system for reception on the way, and cuts the noise so that this radio wave is free from interference. This superconducting filter 4 needs to be cooled to a cryogenic temperature, and the cold stage 7 of the cryogenic refrigerator 7
It is installed on a.

The received signal passes through the superconducting filter 4, is amplified by the low noise amplifier 5, exits the cold box 6, and is sent to the received signal processing system. The low noise amplifier 5 is also installed on the cold stage 7a. The cryogenic refrigerator 7 may be any cold storage refrigerator, such as a Gifode McMahon refrigerator, a Stirling refrigerator, a pulse tube refrigerator, etc., as long as it is a cold storage refrigerator. The cold stage 7a, the connecting member 7b, the cryogenic compressor 7c and the piping between them constitute the cryogenic refrigerator 7.

Taking a Stirling refrigerator as an example, helium He is used as a refrigerant for compression by a compressor having an opposed piston, and a refrigerator is equipped with a displacer whose one end is supported by a spring inside the cylinder. The displacer is filled with a cool storage material having a low specific heat at a low temperature, which is stored in the cool storage material by adiabatic expansion of the refrigerant gas, and by repeating this, it is cooled to an extremely low temperature of about 70K. This cycle is a reverse Stirling cycle. A disk-shaped cold stage made of a material having good heat conductivity is fixed to the tip of the cooled cylinder, and the superconducting filter 4 and the low noise amplifier 5 are installed to cool the cylinder.

Conventionally, as cryogenic refrigerators, cryopumps, semiconductor cooling devices, cryogen condensers, etc. have been used, and relatively few urgent maintenance requests such as in-plant use have been made. However, nowadays, superconducting filters are used in a huge number of base stations, and a cryogenic refrigerator is used to cool this filter. It is necessary to promptly detect the cryogenic refrigerator that is used in this vast number of base stations and repair and restore it.

An object of the present invention is to find a refrigerator with a low refrigerating performance from such a huge number of base stations and immediately perform maintenance and inspection processing. The purpose is to provide a device.

[0023]

The present invention employs the following means in order to achieve the above object. (1) In a failure repair device for a cryogenic refrigerator, a cold box, a cold stage provided in the cold box, a cryogenic compressor for cooling the cold stage, a circuit element installed in the cold stage, and A sensor having an arbitrary detection function provided in any of the constituent elements, and a control device for inputting a detection signal of the sensor and controlling failure repair of the cryogenic refrigerator when the value of the detection signal is determined to be abnormal It is characterized by having and. (2) In the cryogenic refrigerator failure repair device according to (1) above, a refrigerant gas tank is connected to the cryogenic compressor via a refrigerant gas supply valve, and a refrigerant gas discharge valve having one end open to the atmosphere is provided. The end is connected to the cryogenic compressor, and the control device replaces the refrigerant gas by the failure repair control. (3) In the cryogenic refrigerator failure repair device according to (1) or (2), the sensor is a temperature sensor and a pressure sensor, and the temperature sensor is the circuit element, the cold stage, and the cryogenic compressor. And the pressure sensor is provided in the cryogenic compressor. (4) In the failure repair device for a cryogenic refrigerator described in (3) above, the control device causes a value of a detection signal of an arbitrary sensor among the sensors, a value of a feeding current of the cryogenic compressor, and a value thereof. When it was determined that any detected value out of the voltage value and its pressure value was abnormal, the cryogenic compressor was stopped and controlled, abnormal information was transmitted to the repair station, and it was determined that the detected value was not abnormal. At this time, a gas replacement process is performed. (5) In the cryogenic refrigerator failure repair device according to any one of (1) to (4), the circuit element is a superconducting filter. (6) In the method of repairing a failure of a cryogenic refrigerator, a step of cooling a cold stage in which a cryogenic compressor is provided in a cold box and a circuit element is placed to a cryogenic temperature, and a sensor having a specific detection function is one of the constituent elements. A step of detecting a specific function of any of the above, a control device selects a value of a detection signal of any sensor of the respective sensors, a feed current value of the cryogenic compressor, a voltage value thereof and a pressure value thereof. Determining whether or not any detected value is abnormal, stopping control of the cryogenic compressor when determining that the detected value is abnormal in the step, and transmitting abnormal information to a repair station, When it is determined that the detected value is not abnormal in step, the gas replacement process is performed.

First Embodiment of the Present Invention A first embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention.

The circuit of FIG. 1 has a duplex configuration including a transmission signal system and a reception signal system. In a reception signal system that outputs a reception signal by connecting a superconducting filter 4 and a low noise amplifier 5 which are circuit elements to the antenna 3, the superconducting filter 4 and the low noise amplifier 5 housed in a cold box 6 are cold staged. The structure of cooling by the cryogenic compressor 7c via 7a is the same as that of FIG.

According to the present invention, a failure repair device having a control device 8 or the like as a control unit provided after the low noise amplifier 5 of the received signal system, which is a circuit element, detects a failure of the cryogenic refrigerator, repairs and protects the abnormality. The processing of is performed.

The failure repair device includes a control device 8, various sensors 21 to 25 and respective sensor lines 9a and 10 to 13 which are inputs to the control device 8, and a valve operation line 14 which is an output from the control device 8. 17 and an abnormality notification line 19.

The control device 8 has an input circuit for inputting the detection signal of each sensor, an arithmetic circuit, a memory circuit for storing judgment reference data and each procedure, and an output circuit, and is controlled by various programs incorporated therein. . The function setting of the control device 8 can be realized in any form such as function setting by a combination of gate circuits, function setting by a program, and function setting by a combination of mask patterns.

A compressor power supply line 9 connects the cryogenic compressor 7c to the power supply terminal. There are various compressors, for example, a Stirling compressor has a coil inside. An alternating current from a power supply line is applied to this coil to generate a magnetic flux, and the attraction force between the magnetic flux and a magnet (not shown) overcomes the spring force to move the piston and compress the refrigerant gas. If the alternating current changes to zero in that state, the attraction force disappears and the biased spring force causes the piston to move back to its original position. The above is repeated.

Other types, such as scroll type compressors that constantly rotate to generate pressure can be used as well.

The control device 8 inputs the voltage value and the current value of the compressor power supply line 9 through the compressor current voltage sensor line 9a in order to monitor the voltage value and the current value of the cryogenic compressor 7c. . The switch circuit 20 is provided in the compressor power supply line 9 to open and close the power supply line 9.

The controller 8 controls the switch circuit 20 via the compressor control line 9b to control the cryogenic compressor 7c.
Operate the start / stop of.

The control device 8 takes in the temperature information detected by the temperature sensor 24 provided in the cryogenic compressor 7c via the compressor temperature sensor line 10.

The controller 8 fetches the temperature detection data of the temperature sensor 21 provided on the cold stage 7a via the cold stage temperature sensor line 11.

The control device 8 takes in the temperature information detected by the temperature sensor 22 provided on the object to be cooled in the cold box 6 via the object temperature sensor line 12 to be cooled.

The object to be cooled is a circuit element or the like, for example, a superconducting filter, a low noise amplifier, a feeder wire, a coil, or the like, and the one whose characteristics are greatly improved by cooling to an extremely low temperature is applicable. .

The control device 8 takes in the refrigerant gas pressure value inside the compressor of the compressor pressure sensor 23 provided in the cryogenic compressor 7c through the compressor pressure sensor line 13.

The refrigerant gas replacement valve 15 is provided in the middle of the gas tube connecting the refrigerant gas tank 18 and the cryogenic compressor 7c, and is in a closed state during the operation of the compressor.

The control device 8 sends an operation signal for opening and closing the refrigerant gas replacement valve 15 to the valve 15 via the refrigerant gas replacement valve operation line 14.

The refrigerant gas discharge valve 16 is connected to the cryogenic compressor 7c at one end and is open to the atmosphere at the other end. The discharge valve 16 is normally closed.

The refrigerant gas is, for example, He, which is inert and can be released into the atmosphere without any problem, but if it cannot be released, it is sucked and stored in a tank or the like.

The controller 8 opens and closes the refrigerant gas discharge valve 16 via the refrigerant gas discharge valve operation line 17.

The refrigerant gas tank 18 stores the refrigerant gas,
It is connected to the cryogenic compressor 7c via the refrigerant gas replacement valve 15.

The cryogenic compressor 7c includes a refrigerant gas replacement valve 15 and a refrigerant gas tank 1 connected to the valve 15.
8 and a refrigerant gas discharge valve 16.

The control device 8 is connected to the received signal processing system via the abnormality notification line 19 and further to the repair station via a public telephone line or the like.

The controller 8 is connected between the latter stage of the cold box 6 and the cryogenic compressor 7c.

Cold stage temperature sensor line 11
Since the object temperature sensor line 12 to be cooled is wired in the cold box 6 which does not like the intrusion of heat, it is possible to use an optical cable to prevent the intrusion of heat.

The types of sensors, the locations of the sensors, the number of sensors, etc. are set according to the degree of necessity of state detection. (Fault Repair Control) FIG. 2 shows a control flow of the fault repair device for the cryogenic refrigerator in the control device serving as the control means of the present invention.

The controller 8 executes the following typical control flow of the failure repair device for the cryogenic refrigerator.

The control device 8 starts this control flow, and takes in the temperature information A detected by the temperature sensor 22 provided on (1) the object to be cooled, the superconducting filter in the embodiment, via the line 12 (step S15). ). (2) It is determined whether or not the temperature information A detected by the temperature sensor 22 provided in the superconducting filter that has been taken in exceeds a preset cooling temperature threshold value. When it is determined that it does not exceed the threshold value, the process returns to the start ( Step S16). (3) When it is determined that the detected temperature information A exceeds the cooling temperature threshold value, the detected temperature information C of the temperature sensor 24 provided in the cryogenic compressor 7c is checked in order to investigate the most probable cause. It is read (step S17). (4) When it is determined that the temperature of the detected temperature information C exceeds the preset threshold value, the process proceeds to step S36 (step S18). However, a temperature range that exceeds the threshold value defines an abnormal temperature range that cannot be automatically repaired. (5) When it is determined in step S18 that the detected temperature information C of the cryogenic compressor 7c does not exceed the threshold value,
Next, in order to check the power supply status to the cryogenic compressor 7c, which has a high possibility, the current value of the power supply line 9 is fetched via the line 9a (step S19). (6) It is determined whether or not the current value of the fetched line 9 exceeds the threshold value. When it is determined that the current value exceeds the threshold value, the repair must be performed by a person, and the process proceeds to step S36 (step S20). (7) When it is determined in step S20 that the current value of the line 9 does not exceed the threshold value, the voltage value of the line 9 is fetched via the line 9a (step S21). (8) It is determined whether or not the voltage value of the fetched line 9 exceeds a threshold value. When it is determined that the voltage value exceeds the threshold value, the repair is also performed by a person, so the process proceeds to step S36 (step S22). (9) When it is determined that the voltage value of the line 9 does not exceed the threshold value, the temperature sensor 2 provided in the cold stage 7a
The detected temperature information B of 1 is fetched through the line 12 (step S23). (10) It is determined whether or not the temperature information B detected by the temperature sensor 21 provided in the cold stage 7a that has been taken in exceeds a preset cooling temperature threshold value, and if it exceeds, the process proceeds to step S36 (step S24). (11) When the detected temperature of the cold stage 7a does not exceed the cooling temperature threshold and the temperature of the cold stage is normal, disturbances such as those due to a defective interface portion of the object to be cooled or heat intrusion are detected. can do. Here, when the cold stage is not cooled, it is necessary to check the pressure of the refrigerant gas sealed in the connecting member 7b, and the pressure of the compressor incorporated in the cryogenic compressor 7c detected by the compressor pressure sensor 23. Is taken in through the compressor pressure sensor line 13 (step S
25). (12) When it is determined that the pressure of the compressor exceeds the threshold value, the process proceeds to step S36 (step S26). (13) Next, the procedure for gas replacement is started. First, gas replacement means that impurities and impure gas inside the connecting member 7b and the like are expelled to improve the purity of the refrigerant gas. This significantly improves the performance of the refrigerator. The reason why the gas replacement is necessary is considered that abrasion powder or the like is generated from the sliding portion of the connecting member 7b, or the powdery regenerator material inside the refrigerator flows out. It is also conceivable that an unreasonable external force acts on the connecting member 7b so that a portion that should not originally come into contact with the connecting member 7b.

The procedure for gas replacement is as follows. First, when it is determined that the pressure of the compressor does not exceed the threshold value, the refrigerant gas tank 1
The remaining gas amount of 8 is calculated for the number of times of the replacement gas amount. For example, when the refrigerant gas tank 18 is fully filled, the replacement gas amount is calculated in advance and the number of times of use is subtracted, or the pressure value of the refrigerant gas tank 18 is detected and the replacement gas amount is calculated from the tank volume. It is possible to obtain in advance how many times. When the calculated replacement gas amount does not exceed the threshold value, the process proceeds to step S36 (step S28). (14) When the determined replacement gas amount exceeds the threshold value and it is determined that gas replacement can be performed to drive out impurities and impure gas and increase the purity of the refrigerant gas, a stop signal is output to the switch circuit 20 via the line 9b. The switch circuit 20 is turned off to stop the compressor (step S29). (15) Next, the pressure value detected by the compressor pressure sensor 23 is taken in through the line 13, and the refrigerant gas release valve 16 is opened while confirming that the detected pressure value exceeds a predetermined threshold value set above atmospheric pressure. A command is output to open the valve 16 to the atmosphere, and the contaminated refrigerant gas is discharged from the cryogenic compressor 7c to the atmosphere (step S30). (16) Thereafter, a command to close the refrigerant gas discharge valve 16 is output to close the valve 16 and the refrigerant gas replacement valve 1
A command to open 5 is output to the line 14 and the valve 15
The refrigerant gas tank 18 is opened and a high-purity refrigerant gas contained in the refrigerant gas tank 18 is filled in the cryogenic compressor 7c (step S3).
1). (17) At this time, the pressure detection value of the compressor pressure sensor 23 is taken in via the compressor pressure sensor line 13,
When the detected pressure value reaches a predetermined pressure value, a command to close the refrigerant gas replacement valve 15 is output to close the refrigerant gas replacement valve 15 (step S32). (18) Next, an ON signal is output to the switch circuit 20 via the compressor control line 9b to start the operation of the cryogenic compressor 7c (step S33). (19) Next, the temperature information detected by the temperature sensor 22 provided in the superconducting filter which is the object to be cooled is fetched (step S34). (20) Judge whether the detected temperature exceeds a threshold value,
When it is determined that the threshold value is exceeded, the process returns to step S28, and when it is determined that the threshold value is not exceeded, step S3.
7 (step S35). (21) When it is determined that an abnormal state cannot be repaired without the assistance of a person, that is, when the compressor temperature is abnormal in step S18, it is determined that the power supply current and voltage of the compressor are abnormal in steps S20 and S22. When it is determined that the cold stage temperature is abnormal in step S24, the compressor pressure is abnormal in step S26, and the replacement gas amount in the refrigerant gas tank is insufficient in step S28, Switch circuit 20 provided in the compressor power supply line 9 to the cryogenic compressor 7c
Is turned off by the control signal output to the compressor control line 9b, and the cryogenic compressor 7c is stopped (step S36). (22) After the stop control, the control device 8 sends information about the temperature abnormality, information about maintenance, repair, etc. to the abnormality notification line 1
9 to the repair station (step S3)
7).

As a result, step S28-
The control up to S37 is as follows.

The refrigerator is operated to confirm whether or not the object to be cooled is cooled, and if cooled, this information is sent to the repair station via the abnormality notification line 19 just in case. If it does not cool down, the procedure for gas replacement is returned to and continues until there is no more gas in the refrigerant gas tank 18. If it is still unsuccessful, the connection member 7b is stopped and this information is sent to the repair station through the abnormality notification line 19. (Cryogenic Refrigerator Failure Repair Method of the Present Invention) The cryogenic refrigerator failure repair method of the present invention specifically includes the above steps according to the first embodiment. become that way. .

“Step of cooling a cold stage in which a cryogenic compressor is provided in a cold box and mounting a circuit element to a cryogenic temperature, a sensor having a specific detection function detects a specific function of any one of the components. Whether the value of the detection signal of any one of the sensors, the power supply current value of the cryogenic compressor, its voltage value, and its pressure value is abnormal, Step of determining whether or not, when it is determined that the detected value is abnormal in the step, stop control of the cryogenic compressor,
A method of repairing a failure of a cryogenic refrigerator, comprising: a step of transmitting abnormality information to a repair station; and a step of performing gas replacement processing when it is determined that the detected value is not abnormal in the step ". (Partial modification example of the control flow) (a) In step S18, the threshold value is set to the abnormal temperature value, but since the possibility that it is a change only during measurement cannot be eliminated, the following measurement condition is further added. It is also possible. Sampling a time interval exceeding the threshold,
A method to judge the length of the time interval compared with the threshold. A method of calculating [detection value−threshold value = deviation value] and determining a time change of the deviation value, for example, an abnormal tendency that gradually increases, a repairable tendency that gradually decreases, and the like. (B) In steps S20 and S22, the control mode of the electric motor for driving the compressor is not taken into consideration.
The following measurement conditions can be further added. A method of calculating the thresholds of the current and voltage at the time of detection on the precondition that the control mode of the motor, that is, full voltage drive or soft start drive is a prerequisite. (C) In the above flow, from step S15 to step S26, each detected value is determined to be abnormal in the order of steps. However, it is necessary to perform this step order or all of them in accordance with the design of the control mode. Therefore, only the abnormality determination of any detected value from step S15 to step S26 is executed. (D) Based on the explanation of (c) above, when all of the steps S15 to S26 in the flow are not executed and only any of the steps is executed and it is determined that there is an abnormality, It is also possible to omit the intermediate steps and use a flow for performing gas replacement from step S27 to step S32. (Example of temperature detection of cooled object) The cooled object of the present invention is
The above-mentioned superconducting filter, low-noise amplifier, feeder line, oscillator, etc., whose heat generation is a problem, correspond to this.

A method of temperature detection for a typical superconducting filter will be described. First, the characteristics of the superconducting filter will be described. (Superconducting Filter) In the superconducting filter that represents the object to be cooled of the present invention, various characteristics described below change with temperature. (A) In the superconducting filter, in this embodiment, the microstrip circuit is configured with one of the conductors formed on both surfaces of the dielectric substrate as the conductor line and the other as the ground. At this time, in order to realize a low-loss microstrip circuit, it is necessary to reduce the surface resistance of the conductors on both sides. Therefore, a yttrium (YBCO) oxide superconducting (hereinafter referred to as “YBCO”) thin film is formed on both surfaces of the MgO substrate. Next, the temperature change of this surface resistance is shown.

FIG. 8 is a diagram showing the temperature change of the surface resistance of the YBCO thin film in the 30 GHz band. In particular,
FIG. 3 is a diagram showing temperature changes in surface resistance of Cu and a YBCO thin film that serves as a superconducting filter. The horizontal axis represents temperature (K) and the vertical axis represents surface resistance value (Ω). According to this figure, the surface resistance of YBCO decreases remarkably as the temperature decreases from around 80K,
A value of about 400 μΩ was obtained at around 20K. Regarding this characteristic diagram, if the surface resistance of the superconducting filter is known, the temperature can be known from this characteristic diagram. (A) The characteristic described below is the temperature change of the unloaded Q value of the superconducting filter.

FIG. 9 shows an unloaded Q value (vertical axis) at 20 GHz of a microstrip resonator using a YBCO thin film.
It is a figure which shows the temperature (horizontal axis) change of.

In this characteristic diagram, in the microstrip resonator, the length of the linear resonator corresponds to a half wavelength, and the fundamental resonance frequency is about 20 GHz. Due to its characteristics,
As shown in FIG. 9, a very high no-load Q value of about 20,000 is realized near 60K. If the unloaded Q value of the superconducting filter is known from this characteristic diagram, the temperature (K)
Will be understood. (C) The characteristic described below is the temperature change of the insertion loss of the superconducting filter.

FIG. 10 is a diagram showing the temperature change of the insertion loss at the band center frequency of the superconducting filter.

According to this characteristic diagram, the insertion loss remarkably decreases from around 90 K where the YBCO thin film becomes superconducting,
It becomes 1 dB or less at 77 K or less. This temperature change corresponds well with the temperature change of the surface resistance. Also, it can be seen that if cooled to 70 K or less, a very small insertion loss of 0.5 dB or less can be obtained. If the insertion loss is known, the temperature (K)
Will be understood. (Temperature measurement method based on various characteristics) In addition to the method of measuring temperature by directly providing a temperature sensor on the superconducting filter,
From the above various characteristics, it is possible to measure the temperature as follows. (A ') A method of measuring the surface resistance value of the superconducting filter by the two-resonator method using a sapphire cylindrical resonator, and obtaining the temperature (K) from the surface resistance value measured in the characteristic diagram of FIG. 8 and comparing it with a threshold value. . (A ') The circuit is set as a superconducting filter and a no-load circuit of the power supply, and the circuit current is measured as a frequency change characteristic diagram including the circuit resonance frequency. From the maximum current value, 1 / (( 2) (Difference Δf from the resonance frequency f ₀ ) in the case of ^1/2 ) is obtained, and is obtained as the no-load Q value = f ₀ / 2Δf. From the Q value obtained in the characteristic diagram of FIG.
And a method of comparing with a threshold value. However, the resonance frequency gradually decreases or increases according to the change of the temperature (K), for example, 70
Since the resonance frequency changes by about 2 MHz between K and 20K, the resonance frequency also needs to be corrected according to this characteristic. (C) While operating the superconducting filter at the center frequency of the band, the input power and output power before and after the filter are obtained, and the insertion loss is obtained. A method of obtaining the temperature (K) from the insertion loss value obtained in the characteristic diagram of FIG. 10 and comparing it with a threshold value. (Embodiment 2 of the present invention) FIG. 3 is a diagram showing an embodiment in which a high temperature superconducting device such as a superconducting filter is applied to a millimeter-wave communication system for mounting on a satellite, and further the control device in the embodiment 1 of the present invention is provided Is.

The system shown in FIG. 3 is a vent pipe repeater using a phased array antenna or the like, and has a superconducting filter, a low noise amplifier, a frequency converter, and a feeder system including a high temperature superconducting millimeter wave device and a cryogenic refrigeration. Machine, control device.

Superconducting filter and cooling LNA in FIG.
The (amplifier) is cooled by using the configuration of the cryogenic refrigerator described in the first embodiment. The control of the cryogenic refrigerator is performed by the control device according to the flow.

If all the performance increase due to adopting this configuration is directed to the communication capacity (transmission speed), the satellite 1
The communication capacity per machine can be improved several times. Furthermore, moving image communication becomes possible. Further, the failure repair processing can be automatically performed.

[0065]

According to the present invention, the temperature abnormality of the circuit element in the cold box can be constantly monitored, and when the abnormality occurs, the repair processing such as the repair can be immediately performed.

According to the present invention, it is possible to find a refrigerator having a low refrigerating performance from a huge number of base stations and perform a repair process.

According to the present invention, the abnormality of the components including the object to be cooled is checked and the abnormality is repaired. Therefore, since the remote monitoring is always performed, the labor and cost for maintenance and inspection are not required. The necessary repair can be performed only when an abnormal condition occurs. As a result, since manpower is not required at all times, the required number of base stations can be provided without considering manpower. In addition, the repair process can be performed automatically.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a first embodiment of a receiving system of the present invention.

FIG. 2 is a control flow chart of a failure repair device for a cryogenic refrigerator in the control device of the present invention.

FIG. 3 is a second embodiment in which a high temperature superconducting device such as a superconducting filter is applied to the satellite-mounted millimeter-wave communication system of the present invention.
It is a block configuration diagram showing.

FIG. 4 is a block diagram of a base station of a conventional receiving system.

FIG. 5 is a schematic diagram showing a relationship between a conventional base station and a mobile phone.

FIG. 6 is a diagram showing temperature changes of an amplifier gain and an amplifier noise figure of a low noise amplifier of a receiving system which operates at 77K in a conventional high sensitivity wireless receiver.

FIG. 7 is a diagram showing a temperature change of insertion loss of a reception band filter at 77K in a conventional high sensitivity wireless receiver.

FIG. 8 is a diagram showing a temperature change of surface resistance of a YBCO thin film in a 30 GHz band.

FIG. 9 is a view showing a temperature change of an unloaded Q value at 20 GHz of a microstrip resonator using a YBCO thin film.

FIG. 10 is a diagram showing a temperature change of insertion loss at a band center frequency of a superconducting filter.

[Explanation of symbols]

1 mobile phone 2 base stations 3 antennas 4 Superconducting filter 5 amplifier 6 cold box 7 Cryogenic refrigerator 7a cold stage 7b Connection member 7c Cryogenic compressor 8 control device 9 Compressor power line 9a Compressor current voltage sensor line 9b Compressor control line 10 Compressor temperature sensor line 11 Cold stage temperature sensor line 12 Coolant temperature sensor line 13 Compressor pressure sensor line 14 Refrigerant gas replacement valve operation line 15 Refrigerant gas replacement valve 16 Refrigerant gas release valve 17 Refrigerant gas release valve operation line 18 Refrigerant gas tank 19 Abnormality report line 20 switch circuits 21, 22, 24 Temperature sensor 23 Compressor pressure sensor 25 Voltage / current detection sensor

Claims (6)

[Claims] 1. A cold box, a cold stage provided in the cold box, a cryogenic compressor for cooling the cold stage, a circuit element installed in the cold stage, and any of the constituent elements. And a control device for inputting a detection signal of the sensor and controlling the failure repair of the cryogenic refrigerator when the value of the detection signal is judged to be abnormal. Cryogenic refrigerator failure repair device. 2. A cryogenic refrigerator failure repair apparatus according to claim 1, wherein a refrigerant gas tank is connected to said cryogenic compressor through a refrigerant gas supply valve, and a refrigerant gas discharge valve having one end open to the atmosphere is provided. A failure repair device for a cryogenic refrigerator, characterized in that the other end is connected to the cryogenic compressor, and the controller replaces the refrigerant gas by the failure repair control. 3. The cryogenic refrigerator failure repair apparatus according to claim 1, wherein the sensor is a temperature sensor and a pressure sensor, and the temperature sensor is the circuit element, the cold stage, and the cryogenic compressor. A failure repair device for a cryogenic refrigerator, characterized in that the pressure sensor is provided in the cryogenic compressor. 4. The cryogenic refrigerator failure repair apparatus according to claim 3, wherein the controller controls a value of a detection signal of an arbitrary sensor among the sensors and a power supply current value of the cryogenic compressor. When it is determined that any detected value among the voltage value and the pressure value is abnormal, the cryogenic compressor is stopped and controlled, abnormal information is transmitted to a repair station, and it is determined that the detected value is not abnormal. A repair device for a cryogenic refrigerator, which is characterized by performing a gas replacement process at the time. 5. A failure repair apparatus for a cryogenic refrigerator according to claim 1, wherein the circuit element is a superconducting filter. 6. A step of cooling a cold stage in which a cryogenic compressor is provided in a cold box and mounting a circuit element to a cryogenic temperature, and a sensor of a specific detection function detects a specific function of any one of the constituent elements. Step, the control device, the value of the detection signal of any sensor of the above-mentioned each sensor, the feeding current value of the cryogenic compressor, its voltage value and any detected value of its pressure value is abnormal Determining whether or not the detected value is abnormal in the step, stopping the cryogenic compressor and transmitting abnormality information to a repair station, the detected value is not abnormal in the step When it is determined that the above, the method for repairing a failure of a cryogenic refrigerator is characterized by comprising a step of performing a gas replacement process.