JPS59208360A - Method of controlling refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

In other words, ff. What is the compression piston (also called the power piston) and the t++ k piston (also called the displacer or floating screw I/n)? The working fluid (helium, helium, etc.) is controlled by nine independent reciprocating mechanisms without mechanical connection.
The compression space and the expansion space, where the volume and pressure changes are expressed, are communicated through a conduit, a heat exchanger, a regenerator, etc., and the expansion piston is driven at an arbitrary rotational phase different from that of the compression piston. This is related to the control method for refrigerators. . The idea of operating the expansion piston and compression piston of a refrigerator using an independent reciprocating mechanism using the Stirling cycle, which consists of two isovolumic processes and an isothermal process, was proposed in Japanese Patent Publication No. 1973-
No. 13588, No. 5], No. 8255, No. d, and No. 7-16591. These conventional techniques obtain a phase difference by adjusting a single point on the switch-on portion of each reciprocating mechanism, and therefore have difficulty in obtaining a stable refrigerating output. This invention is intended to solve the above-mentioned problems of the prior art. A technical means is used to create an arbitrary phase difference between both pistons using signals from both sensors. By adopting such a technical means, the acceleration and deceleration of the expansion piston can be controlled, making it possible to effectively handle extremely low temperatures. It has a stable refrigeration temperature and refrigeration output, and has the effect of minimizing mechanical vibrations on the object to be cooled.Examples of the present invention will be explained with reference to the drawings.From several atmospheres to 10 Compressed air 2 (hereinafter referred to as "fluid") in the cylinder 1 is filled with several atmospheres of fluid (hereinafter referred to as "fluid"). The raw material in the compressed 91rrJ is contaminated with the dial ram 5, guide piston 6,
Connecting rod 7, sensor 11 [for detecting rotational axis position, rotational speed, etc., for example, optical encoder] attached to the crankcase F9, the electric motor is connected to the electric motor, which can change the rotation speed, has a gear drive, etc. [Hereinafter, referred to as the main motor] The volume is changed by the main motor 10 which rotates at a constant speed. This fl-
The fluid in the compressor 2 is compressed by the center 30 (1'W for detecting rotational axis position 1, rotational speed, etc.) through the crankshaft l-28, the connecting rod 27, the guide piston 26, and the piston rod 25. , control motor 29 (AC or I)
C drive], it is approximately 45 degrees to l from the compression piston 3.
25 # [i Melon temperature is usually about 60 degrees, but it varies depending on the dead volume of the conduit 130, pressure loss, and freezing temperature. In a refrigerator where the expansion piston is reciprocated by the same crank shunt as the compression piston, the range is from 90 degrees to 120 V.] The expansion piston 22 is integrated with the small diameter expansion piston 18 that reciprocates in an advanced phase. A heat exchanger 12, a flexible conduit 13, a fluid inlet/outlet 14, a regenerator inlet/outlet 1]
42.Regenerator 4? , 4 (' y, 'r= r"
The pressure changes approximately sinusoidally through the inlet/outlet 43. direction, sky m]2
The volume of 3 is zero when the volumes of the second expansion spaces 20 and i6 of Q1 and Q4 are respectively at fL, and 15 is a cold head that freezes an object (not shown) to be cooled, and the freezing temperature is 1 in absolute degrees.
0 to 30K VC. 60-1 for the same purpose as 19ba15
It will be 20K. 17 is/''・diameter portion Ruji1晟cylinder, 2
1 is a large diameter expansion sill, and the expansion piston 22 is
Becomes convex. When three cold heads are required, an even thinner J expansion piston is connected to the small diameter expansion piston 18 by incorporating a regenerator and allowing fluid to flow in and out, and the expansion cylinder is also shaped accordingly. Also, when there is only one cold head, there is only the expansion piston &j1.22 and the cold cylinder 21 in the large diameter part. Incidentally, the cold head and the expansion cylinder are located in a wall case (not shown). The stamp fin box 24 and the fluid purifier 33 are used to maintain a high purity of the fluid that generates the low temperature while blowing and recirculating the movement between the compressor and the cedar expansion space.
The diaphragm completely prevents lubricating oil and other fluids from entering the fluid, and prevents fatigue deterioration due to the pressure difference between the fluids received from both sides of the 5. The pressure of the same air as the fluid (13, helium contaminated with oil or other substances) is reduced. Pressure flil-i controller 32, valve 44,
So, what is the operating force of the fluid in the purifier 33 and the buffer space 35, 36 with high purity gas? Optimize. Further, 34 is a piston ring, 39 bearing, 50 main motor drive device, 51 phase difference detection system, 52 phase difference setting value input system, 53 comparison calculation thread, 54 belief conversion thread, 55 drive signal output system, 2 yohi 56 9j1] Show the required equipment. A method of generating low-temperature heat by reciprocating the movement of each piston according to the present invention with the expansion piston 22 being 90 degrees ahead of the compression piston 3 will be described. Next, details of the system@1 method will be described using Figures 2 and 3. When the expansion piston is set to, for example, 90 degrees by the set value input system 52, the main motor day shift device 50 irC, the movement of the compression piston 3 (not By the phase difference control system described later,
It moves back and forth 90 luni ahead of the pressure r toviston. Now, when the expansion piston 22 is close to the top dead center - J'' Heat dissipation [...] Part of the compression rod enters the space 23 V (isothermal compression process) from the space entrance/exit 14 (isothermal compression process). When the compression piston 3 approaches the top dead center and the expansion piston 22 begins to move toward the bottom dead center , the fluid in the compression space 2 and the space 23 is in four pipes 13
There is a part of the inside of the regenerator 41 from the regenerator entrance/exit 42,'
While being completely cooled by TO, the fluid enters the first expansion space 20 and the second expansion space 16 through the space entrance/exit 43.39, where the volume of the fluid is almost constant (the pressure of the fluid decreases) (equal valley process). ). The fluid in each expansion air [H] cooled by the expansion piston 2
2 is about to reach bottom dead center, the cold head 19.15 expands isothermally while absorbing heat from a cooling body (not shown) (isothermal expansion process). At this time, some of the work of expanding the fluid is done by the expansion piston 22 to rotate the crankshaft 28, but most of it is consumed by the return of the compression piston 3 through the conduit 13. Finally, the fluid in the expansion space 20.16 moves toward the top dead center of the expansion piston 22 and the bottom dead center of the compression piston, so that the cold energy is recovered by the regenerator +1.40 from the space inlet/outlet 43.39. Entrance/exit 4
2, space 23, space entrance/exit 14, conduit 13, heat exchanger 1
2, the compressed air 2 is returned to the compressed air 2 again at almost room temperature, completing one bucycle (isovolumic process). Low temperature generation is ideal (wa, isothermal compression, isovolume, isothermal expansion,
Although it consists of four processes of equal volume, in reality, the reciprocating movements of the expansion and compression pistons occur smoothly, and the fluid pressure fluctuation ratio accompanying the compression-expansion is approximately 1.8, which is not dizzyingly high. The mechanical vibrations generated by the compression piston due to compression are also mechanical vibrations. Since the expansion piston itself does almost no work, the mechanical vibration (d extremely low) in the cold head 19, i5 is
±1.0 micrometer or less). If you want to reduce the output of the control motor 29 and reduce the cost, including the control system, 1) control the reciprocating part of the expansion piston, 1) expand the expansion piston a little to reduce the motor load. It would be good to generate work sounds. If the connecting part between the expansion piston that reciprocates around the center of the stuff-in box 24 and the piston rod 25 is made thicker, the cross-sectional area of the piston rod is increased relative to the cross-sectional area of the expansion piston, so that the expansion piston does more work downward. . Therefore, the degree of freedom in design of the object to be cooled is large in the equipment shoulder control method of the present invention. The object to be cooled is easily affected by electromagnetic noise and mechanical vibration of the compression piston drive system, and when it is desired to move the expanding piston system far away, the conduit 13 becomes longer, the dead volume inside the piston increases, and the compression ratio increases. Normally, the refrigeration output decreases and the refrigeration temperature becomes unstable. However, in the refrigerator control method of the present invention, as will be described later with reference to FIGS. 2 and 3, the phase difference is completely eliminated. Since it can be adjusted arbitrarily, there is no such drawback. That is, the phase difference is inputted by the phase difference setting value input system 52, for example, 90
If you use a smaller angle, such as 60 degrees or 55#, you can find the optimum operating conditions. FIG. 2 is a block diagram of the control system used in the present invention, which shows motor drive control for reciprocating the compression piston 3 and the KM4 biston 22 with a precisely set phase difference.The control method will be explained below. do. Compression piston reciprocating morph (main motor) 1 (1, L
-Engineer expansion piston reciprocating deafb f■j motor (control) motor) Part 1 of 29! The shaft position and rotation sensor (for example, a rotary optical encoder) 11.30 is directly connected to the crank small mountain 9.28, so these are good...:・Σ! A pulse representing one phase Iζ and a puff sequence having a frequency j' proportional to the speed are output. these hano

[
・S (input to each counter 57.5B and detected as a count v for the phase and rotational speed of each crankshaft moment by moment.Meanwhile, the output speed signal pulse from the sensor input is input to each counter 57.5B. Zhou)7. -'7' (conversion circuit 54
The frequency was changed to 7T! Several drive pulse trains with different frequencies are prepared for 11 cycles for the first speed and for deceleration. The phase of each crankshaft detected by counters 57 and 58 (
The subtracter 51 takes the difference between them, and inputs the actual phase difference to the input of the JL unit 5308. On the other hand, the set phase difference (bow) inputted from the outside by a digital switch 52 is input as the B input of the comparator 53, and its A,
, H is compared. According to A>B, , A=B, and A<B, the sword I speed, period, and deceleration '1' are input to the pulse frequency conversion circuit 54 mentioned above, and a speed control signal to the control motor 29 is input. A pulse train with an appropriate frequency is output as]1
-ru. This pulse signal is converted into a drive 1-h signal suitable for the control motor's power system by a signal Y converter 55, and then input to a drive-mh device 56. With this control method, it is possible to cause all the crankshafts of the expansion pistons to follow each other while maintaining a phase difference equal to the set value. The rotation speed of the expansion piston is always the same as that of the compression piston, and can only the phase difference be changed to follow the control method using the control method block diagram in Figure 2.The rotation speed of the main motor is determined by the number of poles. Conversion, input power frequency conversion, gear ratio conversion, etc. As a specific example of phase difference control, we will describe a male case jl'C in which all pulse motors are used as the control motor 29. Due to its operating principle, a pulse motor reliably follows input pulses and rotates step by step.
, rotation i = speed control can be performed in a loop, simplifying the configuration of the control system. Figure 3 V is the specific 1h]
A block diagram of decorative thread is shown. As a pulse motor5,'
! 11, for example, 200 If a half-rotation type is used, the crankshaft position configuration assembly 11 of the king motor will be 200.
A rotary encoder with an increment of 0 pulses/rotation and a 7-ment Hals output will be used. This encoder, in addition to the upper V increment pulse, also shows the basic position of the V rotation of 1, which is 10 j pulses/revolution.
The signal pulse is also output, and by this zero signal pulse, by clearing the counter COI and counting the increment pulse, the reference A (with the crankshaft of the main motor 10) is
The zero signal pulse generation position, force, and phase angle can be detected. This increment bus (200 pulses/times!
-%) ri monostable multivib [/-ta MMI, 400 pulses/rotation with twice the A wave number in 8 iM2, frequency divided by 1/2 with flip-flop circuit FF, 1
A pulse train of 00 pulses/'revolution is created. This (bow,
Pulse motor sword [Pulse for J deceleration drive and Uodere 2 for Lt]. On the other hand, from the pulse motor's side, tJl, only the zero signal pulse is discarded from the encoder, and the one corresponding to the main/talk increment pulse (YU, counter C(')2VC is manually generated using the pulse motor drive pulse. .C.
O21i) Cleared by zero signal pulse of pulse motor. Two counters COI, CO2? :i, that talent 1. The phase from the reference point of both motors is always a1 number (
, ゛Konaru. In order to eliminate the difference between these counters, CO
For l, full power fiJf t+ is applied through the inverter IN.
+? Enter FAIK. II Full adder (
[:p: (C02] value) - (value of co+) is performed, but as mentioned above, COI at each zero signal)
, CO2 is cleared, so after CO2 is cleared, this difference becomes negative for the song in the ox where C01 is cleared. To prevent distortion, VC, while the difference is negative (C[, this difference IFl, external force \ lateral switch DSI vc
A count of 200 for one rotation is added in the full adder F'A2, so that the output always has a positive phase difference of 6. The next comparator CP compares this phase difference A with the set value B input from the outside via the digital switch DS2. Based on the size of both A1 and B, from CP, A > B XA
= B, ζ number with A < B is output. These three outputs are the gates AN2, AN3, and AN4 for the acceleration, loop 1 (uniform velocity), and deceleration drive loops mentioned above.
Then, ((By taking -12X logical fan r1 by OR2 with these three, an appropriate driving pulse according to the size π between the set value and the actual phase difference is generated) In this way, the phase difference between the main motor and the pulse motor is always controlled to be equal to the set value.
Even if a deviation occurs for some reason, the ratio of the frequencies of the acceleration pulse to the periodic pulse and the periodic pulse to the deceleration pulse is 2, so the phase value within i80 degrees can be corrected within one rotation. @+j As the control motor 29, a motor other than a pulse motor,
For example, the basic control method is the same when using a DC servo motor, a father-flow (periodic) motor, etc., but depending on the speed control method of the motor used (for example, switching M1' to tortoise pressure control, frequency control type, etc.) A conversion string 55 to a drive signal is required upstream of the drive device 56. ′=! For motors with poor mechanical characteristics, mechanical measures 4. Otherwise, it is necessary to add an electric braking mechanism. An experimental example of the present invention will be described. The main motor is a geared motor with a change in the number of poles (4 poles, 6 poles), and the fluid [helium] 2
0 atmospheric pressure, conduit length 15 meters, set phase difference 55 degrees,
At the start of operation (7), it was actually heated at rotation a, approximately 36 ORPM C4 pole, 60H2゜115 gear]. In about 20 minutes, the two cold heads reached 70K. During constant operation, the number of poles is 6 (indication: 240 RPM)
], the phase difference is 63. The vibration in the cold head is -1.0 micrometers or more, and the cooling temperature fluctuation:! It was rare at 2O, 1K. Next, an example will be given of the heavy machinery of this invention. b) Since the compression piston and expansion piston reciprocating centers υ are independent, the vibration at the cord head is extremely low, and even if the distance between the two pistons becomes long, the phase difference Since the adjustment of 11"lgf can be made arbitrarily, the efficiency of the refrigerator does not decrease much. 72 Dia. Since the purifier and all the other parts are connected, when the refrigerator starts operating, the regenerator cools down and the fluid pressure begins to drop, the gas in the crankcase is purified by the purifier and becomes a high-purity gas, which then flows into the fluid. When the operation is stopped, the temperature of the regenerator rises and the fluid pressure increases, so the fluid returns to the crankcase without removing impurities from the purifier. It can be used for a long time without getting dirty. Because it has a two-piece equipment configuration, there is no pressure difference between the two sides of the iaphragm (0.2 atmospheres or less), so there is no noise, so there is no fatigue deterioration. Like the container, it can be used for a long period of ++-41. In addition, the YJ111 body has a special structure that prevents oil from entering, and the piston reciprocating mechanism has two threads 75
1. Improves reliability as a refrigerator because it can be used actively. Since the phase difference control system is digitally controlled, it can be easily combined with the microcombicoord.9 It can easily follow the preset block diagram while taking in information on various conditions from the vibration sensor, cold head temperature sensor, etc. It is possible to automatically control the rotation conditions (phase difference, rotation speed, freezing temperature, etc.) (however, it is also possible to control the rotation conditions).

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a refrigerator embodying an example of the present invention, FIG. 2 is a block diagram of a control example of water retention, and FIG. 3 is a block diagram of a control example using a pulse motor. In the diagram: 3... Compression piston, 10... Main motor,
DESCRIPTION OF SYMBOLS 11... Sensor, 10.22... Expansion piston, 29... Control motor, 30... Sensor, 51... Subtractor, 52... Comparator, 54
...Pulse frequency conversion circuit, 55...Signal converter.

Claims (2)

[Claims] (1) Reciprocating motion of the expansion piston and compression piston (
A control method for a refrigerator consists of an equipment configuration in which the shell structures are independent, and the expansion space and compression space are connected via a heat exchanger, regenerator, conduit, etc., and the refrigerator is reciprocated by a control motor. A rotary shaft position detection sensor is connected to the crankshaft of the expansion piston thread, and a rotary shaft position detection sensor is connected to the crank/gift of the compression piston system, which is reciprocated by a motor. A refrigeration system characterized by causing a compression piston and an expansion piston to reciprocate in accordance with a signal to generate refrigeration.
Law. (2) According to the control method in paragraph (1), two rotary shaft position and speed calibration sensors V7' connected to the crankshafts of the compression piston system and the expansion piston system, respectively, are , and from those values I
The phase difference angle whose force has been measured by the C adder is compared with an arbitrary setting value input digitally from the outside, and acceleration/deceleration is applied to the expansion piston reciprocating motor 1 according to the magnitude of the difference. A method for controlling a refrigerator in which tq+ characteristics are caused to cause refrigeration.