JP2003279182A - Cryogenic refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cryogenic refrigerator capable of contributing energy saving. <P>SOLUTION: Both of a refrigerating part drive motor 23 and a compressor drive motor 12 are driven and controlled by control frequency outputted by an inverter 50. Since the refrigerating part drive motor 23 and the compressor drive motor 12 are controlled at optimum rotating speed suitable for refrigerating load by the inverter 50, the cryogenic refrigerator doesn't consume wasteful energy and can contribute energy saving better. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention of the present application relates to a cryogenic refrigerator, and more particularly to energy saving operation of a cryogenic refrigerator which performs temperature control operation for keeping a refrigeration temperature always constant.

[0002]

2. Description of the Related Art There is a cryogenic refrigerator described in Japanese Patent Application Laid-Open No. 5-113259, which has an improved operation rate of electric power by operating in accordance with a refrigerating load. In this system, a high speed drive and a low speed drive are realized by using a pole number conversion motor as a drive motor of the compressor and changing the number of poles from two poles to four poles by switching control of a relay switch. By changing the driving speed in this way, low-speed driving can be performed when the refrigerating load is small, and high-speed driving can be performed when the refrigerating load is large, and operation can be performed in accordance with the refrigerating load.

[0003]

However, in the above-mentioned conventional cryogenic refrigerator, the number of rotations that the drive motor can select is determined by the number of poles that can be selected, so that only the determined number of rotations can be taken. Therefore, it is not possible to obtain an intermediate rotation speed of the determined rotation speed, and in such a case, a rotation speed higher than that rotation speed is selected and the drive motor is driven. Therefore, during temperature control operation,
It cannot be said that the optimum rotation speed control is always performed, and there is a demand for further optimum rotation speed control from the viewpoint of energy saving.

Therefore, it is a technical problem of the present invention to provide a cryogenic refrigerator which can contribute to further energy saving.

[0005]

The invention according to claim 1 made in order to solve the above technical problems comprises a refrigerating unit having a refrigerating section for generating cold and a refrigerating section drive motor for driving the refrigerating section. A compressor unit having a compressor main body for supplying a high-pressure refrigerant to the refrigeration unit by increasing the pressure of the low-pressure refrigerant sucked from the refrigeration unit, and a compressor drive motor for driving the compressor main body; And a rotation speed converter electrically connected to the refrigerating unit drive motor and the compressor drive motor, the detected temperature being detected by the temperature sensor being input, and the rotation speed. The converter is characterized by continuously controlling the rotation speeds of the refrigeration unit drive motor and the compressor drive motor so that the detected temperature becomes a preset temperature. It is to a cryogenic refrigerator to.

Further, the invention of claim 2 is based on claim 1, wherein the rotation speed converter is such that a detected temperature of the temperature sensor is inputted and the inputted detected temperature becomes the set temperature. And a control amount output from the control device are input, the power source frequency of the power source is converted into a control frequency according to the input control amount, and the refrigeration unit drive motor and the compressor And a frequency converter for outputting to a drive motor.

According to the above-mentioned invention, the rotation speed converter of the refrigeration unit drive motor and the compressor drive motor is adjusted so that the detected temperature becomes a preset temperature with respect to the detected temperature detected by the temperature sensor. Since the number of revolutions is controlled continuously at the same time, the number of revolutions can be controlled more finely than in the conventional case where only a predetermined number of revolutions can be selected. For this reason, it is possible to obtain a cryogenic refrigerator which is always controlled at an optimum rotation speed corresponding to the refrigeration load and which contributes to energy saving without wasteful energy consumption.

The rotation speed converter includes a control device and a frequency converter. The control device controls the detected temperature to a set temperature, outputs the result as a control amount, and outputs the frequency converter. Then, the control amount from the control device is input, the power supply frequency of the power supply is converted to the control frequency according to the input control amount, and the converted control frequency is output to the refrigeration unit drive motor and the compressor drive motor. Preferably. By adopting such a configuration, it is possible to surely perform the refrigeration operation commensurate with the refrigeration load, and it is possible to obtain the cryogenic refrigerator that contributes to energy saving.

In the invention of claim 1, "continuously controlling the rotational speed" is different from the control in the case where the motor rotational speed can only be converted stepwise as in the prior art, unlike the target arbitrary rotational speed. It means a control that can be converted into a number.

In the present specification, the "power supply frequency" is the frequency of the power supply input to the frequency converter, and the "control frequency" is the frequency converter that is influenced by the control amount from the control device. Frequency, that is, the frequency output from the frequency converter.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to embodiments.

FIG. 1 is a system diagram showing an overall configuration of a cryogenic refrigerator in an embodiment of the present invention. In the figure, a cryogenic refrigerator 101 has a compression unit 10, a refrigeration unit 20, a temperature sensor 30, a display (control device) 40, and an inverter (frequency converter) 50.

The compressor unit 10 includes a compressor body 11
, A compressor drive motor 12, and a compressor controller (not shown). The drive part of the compressor main body 11 is operatively connected to the compressor drive motor 12, and is driven by the drive of the compressor drive motor 12 to remove the sucked low-pressure refrigerant gas (mainly He gas). It is for refining high-pressure refrigerant gas as high pressure.

Further, the compressor unit 10 has a discharge port 1
3 and the suction port 14. From the discharge port 13, the high-pressure refrigerant gas purified by the compressor unit 10 is discharged. The discharge port 13 has a high-pressure side pipe 6
1 is connected to one end, and the other end of the high pressure side pipe 61 is connected to the refrigeration unit 20. Therefore, the high-pressure refrigerant gas purified by the compressor is supplied from the discharge port 13 to the refrigeration unit 20 through the high-pressure side pipe 61. On the other hand, one end of the low pressure side pipe 62 is connected to the suction port 14, and the other end of the low pressure side pipe 62 is connected to the refrigeration unit 2
It is connected to 0. Therefore, the low-pressure refrigerant gas in the refrigeration unit 20 passes through the low-pressure side pipe 62 and passes through the suction port 1
4 is sucked into the compressor unit 10.

The refrigeration unit 20 comprises a drive unit 21, a refrigeration unit 22, and a refrigeration unit drive motor 23.

The drive unit 21 has a valve mechanism inside, and the high pressure side pipe 6 is operated by switching operation of the valve mechanism.
The high pressure refrigerant gas of No. 1 is supplied to the freezing unit 22 or the freezing unit 2
The low pressure refrigerant gas in 2 is supplied to the low pressure side pipe 62.

The freezing section 22 has a regenerator 24 inside. The regenerator 24 is operatively connected to the freezing unit drive motor 23 and is driven by the driving of the freezing unit drive motor 23 to generate cold in the freezing unit 22. The refrigerator shown in this example is a GM refrigerator, and the first stage 25
And an example configured as a two-stage GM refrigerator with two stages 26.

A temperature sensor 30 is attached to the second stage 26 of the refrigerating unit 20 to detect the cold generated in the second stage 26. The temperature sensor 30 is electrically connected to the display 40.
In the drawings, the connection configuration shown by the dotted line means an electrical connection configuration, and the connection configuration shown by a solid line means a fluid connection configuration.

The display 40 receives the detected temperature detected by the temperature sensor 30 and displays the temperature. Along with this display, a predetermined control (for example, PID control) is performed in the display 40 so that the detected temperature becomes a preset temperature.
Is done. Then, the control amount is output to the inverter 50 electrically connected to the display 40. Therefore, the display 40 functions not only as a temperature display but also as a control device that outputs a control amount to the inverter 50 such that the temperature detected by the temperature sensor 30 reaches the set temperature.

The inverter (frequency converter) 50 is input with the control amount from the display 40 so that the temperature detected by the temperature sensor 30 becomes the set temperature as described above. The power source A is connected to the inverter 50. The power source A is, for example, a commercial 200V AC power source, and as shown in the figure, is first input to the compressor unit 10, branched from there, and connected to the inverter 50. Then, in the inverter 50, based on the control amount input from the display 40, the power supply frequency of the power supply A (for example, 60H).
z) is converted into a control frequency, and the converted control frequency is output from the output port 51. As shown in the figure, the output port 51 is electrically connected to both the compressor drive motor 12 of the compressor unit 10 and the refrigeration unit drive motor 23 of the refrigeration unit 20.

The display (control device) 40 and the inverter (frequency converter) 50 constitute the rotation speed converter in the present invention.

In the cryogenic refrigerator 101 having the above structure,
When electric power from the power supply A is supplied to the compressor drive motor 12 and the refrigeration unit drive motor 23 via the inverter 50, both motors 12 and 23 are driven. As the compressor drive motor 12 is driven, the compressor main body 11 is driven, and the low pressure refrigerant gas sucked from the suction port 14 is purified to a high pressure. The purified high-pressure refrigerant gas is discharged from the discharge port 13. This high-pressure refrigerant gas is supplied to the high-pressure side pipe 61.
It is supplied to the drive unit 21 of the refrigeration unit 20 through the above, and is supplied into the refrigeration unit 22 at a predetermined opening / closing timing of the drive unit 21. On the other hand, the regenerator 24 in the refrigeration unit 20 is driven as the refrigeration unit drive motor 23 is driven. Then, the high-pressure refrigerant gas supplied to the inside of the freezing section 22 adiabatically expands in the vicinity of the first stage 25 and the second stage 26 at the timing of driving the regenerator 24 and opening / closing the valve of the driving section 21, thereby cooling the cold. Occur. This cold is used to cool the object to be cooled. The low-pressure refrigerant after adiabatic expansion is introduced into the drive unit 21, and the low-pressure side pipe 62 is introduced from the drive unit 21.
Through the suction port 14 and is sucked into the compressor unit 10. In this way, the operation of the cryogenic refrigerator 101 is performed.

During operation of the cryogenic refrigerator 101, the temperature of the second stage 14 is detected by the temperature sensor 30. This detection information (detection temperature) is input to the display 40, and the display 40 displays the temperature. At the same time, control (for example, PID control) is performed so that the detected temperature becomes a preset temperature inside the display 40,
The resulting controlled variable is output to the inverter 50. The inverter 50 converts the power supply frequency of the power supply A into a control frequency based on the control amount input from the display 40, and outputs the control frequency from the output port 51. Since the output port 51 is electrically connected to both the refrigeration unit drive motor 23 of the refrigeration unit 20 and the compressor drive motor 12 of the compressor unit 10, they are drive-controlled at the control frequency received from the inverter 50. Be driven. In this case, since the inverter 50 continuously converts the power supply frequency of the power supply into the target control frequency based on the control amount received from the display 40, it is possible to control the rotation speed only stepwise as in the conventional case. Differently, it is possible to output the optimum frequency according to the situation, whereby the rotation speeds of the compressor drive motor 12 and the refrigeration unit drive motor 23 are continuously controlled,
Drive control is always performed at the optimum rotation speed. By such drive control, the operation of the cryogenic refrigerator 101 is controlled based on the temperature detected by the temperature sensor 30 so that the detected temperature becomes the set temperature most efficiently.

The above control will be described with an example. Eg 2
Assuming that the set temperature in the stage stage 26 is set to 15K, when the heat load in the stage 2 stage 26 is small and the temperature detected by the temperature sensor 30 is 15K or less, the inverter 50 is Frequency control is performed so that both motors 12 and 23 are driven at the lowest frequency. When the heat load on the second stage 26 increases from this state, the temperature detected by the temperature sensor 30 increases. When the detected temperature is about to exceed the set temperature of 15K, the display 40
The control amount (control output) from the inverter increases, which increases the control frequency from the inverter 50. Therefore, the drive speeds of both motors 12 and 23 are also increased, the refrigerating capacity is increased, and the detected temperature is controlled to be 15K.

When lowering the control frequency from the inverter 50, the operation is performed while controlling both the voltage and the frequency so as to suppress the overcurrent.

As described above, in this example, the cryogenic refrigerator 101 includes the refrigerating unit 20 having the refrigerating section 22 for generating cold and the refrigerating section drive motor 23 for driving the refrigerating section 22, and the refrigerating unit. A compressor unit 10 having a compressor body 11 that supplies a high-pressure refrigerant to the refrigeration unit 20 by increasing the pressure of the low-pressure refrigerant sucked from the compressor 20 and a compressor drive motor 12 that drives the compressor body 11, and a refrigeration unit 22. A temperature sensor 30 for detecting a temperature, and a rotation speed converter (display unit 40) to which the detected temperature detected by the temperature sensor 30 is input and which is electrically connected to both the refrigerating unit drive motor 23 and the compressor drive motor 12 And an inverter 50), and a refrigeration unit drive motor so that the detected temperature becomes a preset temperature by a rotation speed converter. 3 and the compressor drive motor 12 are configured so as to continuously control the number of revolutions at the same time, so that both motors can be used on the spot as compared to the conventional case where only the determined number of revolutions can be selected. The rotation speed can be continuously controlled in a finely tuned manner. Therefore, the refrigerating unit driving motor 23 and the compressor driving motor 12 are always controlled at the optimum rotation speed corresponding to the refrigerating load, and the cryogenic refrigerator can contribute to energy saving without wasteful energy consumption. it can.

Further, the rotation speed converter is composed of a display device 40 (control device) and an inverter 50 (frequency converter),
The display 40 controls so that the detected temperature approaches the set temperature, and outputs the result as a control amount. The inverter 50 receives the control amount from the display 40 and outputs the control amount according to the input control amount. Since the power supply frequency of the power supply is converted into the control frequency and output to the refrigerating unit driving motor 23 and the compressor driving motor 12, the refrigerating operation corresponding to the refrigerating load can be reliably performed, and energy saving can be achieved. The cryogenic refrigerator that contributed can be obtained.

In addition, in the inverter 50, when the converted control frequency is low (for example, less than 60 Hz), voltage conversion (voltage control) is also performed, so that overcurrent due to frequency decrease can be effectively prevented.

The present invention is not construed as being limited to the above embodiment. In the above embodiment,
An example in which an AC power source is first input to the compressor unit 50 and then branched from this to supply it to the inverter 50 has been shown.
Inverter 50 and compressor unit 1 using two power sources
It is also possible to separately connect to 0. Various applications are possible without departing from the spirit of the present invention.

[0030]

As described above, according to the present invention,
The cryogenic refrigerator can contribute to energy saving.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a cryogenic refrigerator in an embodiment of the present invention.

[Explanation of symbols]

10 ... Compressor unit 11 ... Compressor body 12 ... Compressor drive motor 13 ... Discharge port 14 ... Suction port 20 ... Refrigeration unit 21 ... Drive section 22 ... Freezing section 23 ... Freezing section drive motor 24 ... Regenerator 30 ... Temperature sensor 40 ... Indicator (control device) (rotation speed converter) 50 ... Inverter (frequency converter) (rotation) Number converter) 101 ... Cryogenic refrigerator

Claims (2)

[Claims] 1. A refrigerating unit having a refrigerating section for generating cold and a refrigerating section drive motor for driving the refrigerating section; A compressor unit having a compressor main body and a compressor drive motor for driving the compressor main body, a temperature sensor for detecting the temperature of the refrigerating section, and the detected temperature detected by the temperature sensor as well as the input. A freezer drive motor and a rotation speed converter electrically connected to the compressor drive motor, wherein the rotation speed converter drives the freezer so that the detected temperature reaches a preset temperature. A cryogenic refrigerator characterized by continuously controlling the rotational speeds of a motor and the compressor driving motor. 2. The control device according to claim 1, wherein the rotation speed converter receives a detection temperature of the temperature sensor and outputs a control amount such that the input detection temperature becomes the set temperature. A frequency conversion in which a control amount output from the control device is input, and a power supply frequency of a power supply is converted into a control frequency according to the input control amount and output to the refrigeration unit drive motor and the compressor drive motor. And a cryogenic refrigerator.