KR20030027761A - Apparatus for, and method of, controlling freezing cycle and temperature controller using it - Google Patents

Abstract

PURPOSE: To provide a refrigerating cycle capable of providing high efficiency and high stability. CONSTITUTION: Valve opening compensation regions are provided above and below a temperature dead zone to compensate a valve opening and cause hunting of the valve opening in order to generate a pulse and an intermediate flow rate of pulse in a pseudo manner.

Description

Control device of refrigeration cycle, control method and temperature controller using it {APPARATUS FOR, AND METHOD OF, CONTROLLING FREEZING CYCLE AND TEMPERATURE CONTROLLER USING IT}

The present invention relates to a control device and a control method of a refrigeration cycle using an electric expansion valve, and a temperature controller using the control device.

An example of the control apparatus of the refrigeration cycle by the conventional electric expansion valve disclosed by Unexamined-Japanese-Patent No. 63-116058 is demonstrated.

7 is a view illustrating a refrigeration cycle, in which a compressor 51, a heat exchanger 52, an electric expansion valve 53, and a heat exchanger 54 are connected in a ring shape. The motor expansion valve opening degree is controlled by the controller 56 which uses the detection temperature of the discharge temperature sensor 55 as an input signal. Solid arrows in the figure indicate the flow direction of the refrigerant.

8 is a block diagram of the control device 56. The output of the temperature detecting means 57 and the output of the target temperature setting means 58 are compared in the temperature comparing means 59, and the degree of changing in the change degree calculating means 60 is calculated according to the output.

Whether the obtained degree of change is the maximum degree of change or the minimum degree of change so far is detected by the degree of change degree comparing means 61. When the maximum degree of change is detected, the degree of change at that time is stored in the maximum degree of change degree storage means 62, and when the minimum degree of change is detected, the degree of change at that time is stored in the minimum degree of change degree storage means 63. The temperature at which the maximum and minimum values are input to the average degree of change calculation unit 64 to output the average degree of change from the degree of change output means 65, while the temperature deadband generating unit 66 stops the change of the degree of change. It causes deadband.

9 is a flowchart of the control device 56. 10 shows changes in discharge temperature and change in degree of change with respect to the target temperature of the discharge temperature. Hereinafter, FIG. 9 and FIG. 10 will be described.

The discharge temperature Td is detected and compared with the target temperature Ts. As a result, when the discharge temperature Td is low, the degree of change is reduced by ΔP. Then, the time is maintained at ΔT time and the second discharge temperature Td is compared with the target temperature Ts. At this time, when the discharge temperature Td is higher than the target temperature Ts, the degree of change is increased by ΔP, and the degree of change before the increase is stored as the minimum degree of change Pmin. Similarly, the comparison between the discharge temperature Td and the target temperature Ts is repeated every ΔT time. When the discharge temperature Td is changed from a state higher than the target temperature Ts to a low state, that is, when the change in the degree of change is changed from ΔP increase to ΔP decrease, the degree of change before ΔP decreases is determined by the maximum degree of change (Pmax). Remember as. When the maximum degree of change Pmax and the minimum degree of change Pmin are determined, the degree of change is changed to the average value (Pmax + Pmin) / 2. In this way, when the output of the average displacement degree calculation means 14 is generated, temperature lines Ts + ΔTh and Ts-ΔTh are formed on the plus side and the minus side of the target temperature Ts, respectively, and the detected discharge temperature Td is Ts + Δ. If the value is equal to or less than Th and equal to or larger than Ts-ΔTh, the discharge temperature Td is made close to the target temperature Ts and stabilized without changing the opening degree of the electric expansion valve.

However, at the low refrigerant flow rate, as shown in Fig. 11, the refrigeration cycle is not stable because the overshoot and undershoot of the discharge temperature are large. In addition, in the motor-expanded valve having a large change in refrigerant flow rate of about one unit (1 pulse) of change in displacement, as shown in Fig. 12, the discharge temperature Td is greatly changed by one pulse change, and the discharge temperature Td is stable in the temperature dead zone. It cannot provide a highly efficient refrigeration cycle.

The control unit of the refrigeration cycle controls the refrigeration cycle consisting of a compressor, a heat exchanger, a valve. The temperature detection means detects the temperature at a predetermined point of the refrigerating cycle, compares the detected temperature with the target temperature determined by the target temperature setting means, and focuses on the temperature dead zone where the valve is not opened or closed based on the result. A control apparatus having a temperature deadband generating means for generating the positive side and the negative side over the positive side and the negative side, wherein the displacement degree correction region generating means and the detection unit generate a region for correcting the degree of change on the positive side and the negative side of the temperature dead band. The displacement degree correction amount calculating means for obtaining the correction amount from the output of the temperature and the target temperature is provided.

Moreover, the control apparatus of the refrigerating cycle of the present invention detects the temperature of a predetermined point of the refrigerating cycle by the temperature detecting means, compares the detected temperature with the target temperature determined by the target temperature setting means, and determines the degree of change based on the result. In addition, the variable degree output means for adjusting the degree of change by reflecting the calculation result of the hunting table operation means for hunting the variable degree is installed.

Moreover, in the control method of the refrigerating cycle of this invention, it detects the temperature of the predetermined point of a refrigerating cycle, compares the detected temperature with the set target temperature, and targets the temperature dead zone which does not open and close a side | surface based on the result. It is generated so as to span the plus side and the minus side around the temperature, a region for correcting the degree of change on the plus side and the minus side of the temperature dead zone is generated, and a correction amount of the degree of change is obtained from the output of the detection temperature and the target temperature.

Moreover, in the control method of the refrigeration cycle of this invention, the temperature of the predetermined part of a refrigeration cycle is detected, the detection temperature is compared with the set target temperature, the degree of change is adjusted based on the result, and the degree of change is also hunted. Let's do it.

The temperature controller of the present invention includes a compressor, a heat exchanger, a valve and at least one of the control device.

1 is a configuration of a refrigeration cycle showing an embodiment of the present invention.

2 is a block diagram of a control device in an embodiment of the present invention.

3 is a flowchart showing control contents in an embodiment of the present invention.

4 is a flow chart.

5 is a flow chart.

FIG. 6 is a time chart showing discharge temperature and degree of change in an embodiment of the present invention. FIG.

7 is a refrigeration cycle block diagram of a conventional example.

8 is a block diagram of a conventional control apparatus.

9 is a flowchart showing the control contents of the conventional example.

10 is a time chart showing a discharge temperature and a degree of change in a conventional example.

Fig. 11 is another time chart showing the discharge temperature and the degree of change in the conventional example.

12 is another time diagram showing a discharge temperature and a degree of change in a conventional example.

Embodiments of the present invention will be described with reference to the drawings.

1 is a view illustrating a refrigeration cycle, in which a compressor 1, a heat exchanger 2, an electric expansion valve 3, and a heat exchanger 4 are connected in a ring shape. The control device 6 which uses the detected temperature of the discharge temperature sensor 5 as an input signal controls the degree of change of the electric expansion valve 3. This configuration also constitutes a thermostat.

2 is a block diagram of the control device 6. The output of the temperature detecting means 7 and the output of the target temperature setting means 8 are compared by the temperature comparing means 9, and the degree of change is calculated by the changing degree calculating means 10 according to the output. Whether the obtained degree of change is the maximum degree of change or the minimum degree of change so far is detected by the degree of change degree comparing means 11. When the maximum degree of change is detected, the degree of change at that time is stored in the maximum degree of change degree storage means 12, and when the minimum degree of change is detected, the degree of change at that time is stored in the minimum degree of change degree storage means 13. The temperature at which the maximum and minimum values are input to the average degree of change calculation means 14 and the average degree of change is output from the degree of change output means 15, while the temperature deadband generating means 16 stops changing the degree of change. It causes deadband.

At low refrigerant flow rate, correction is necessary because the overshoot and undershoot of the discharge temperature are large. Therefore, in the plus side and the minus side of the temperature dead band, a temperature range for correcting the degree of change is generated by the degree of change correction area generating means 17. In the case where the output of the temperature detecting means 7 is the correction area, the change in the degree of correction is determined from the output of the temperature detecting means 7 and the output of the target temperature setting means 8 in the change degree correcting amount calculating means 18. From the output of this correction amount calculation means 18 and the output result of the average displacement degree calculation means 14, the displacement degree hunting table calculation means 19 shows the average displacement degree, a is a positive integer, b is 0≤b≤1 It separates into a water purification part and a hydrophobic part as (a + b). Further, the change degree hunting table calculating means 19 determines the holding time of the change degree (a) and the change degree (a + 1), and outputs the change degree repeatedly from the output means 15. If the output of the temperature detecting means 7 is a correction region, this series of operations are repeated to further correct.

3 to 5 are flowcharts of the control device 6. 6 shows the change in discharge temperature and the change in degree of change with respect to the target temperature of the discharge temperature. Hereinafter, a control method will be described with reference to FIGS. 3 to 6.

The discharge temperature Td is detected and compared with the target temperature Ts. As a result, when the discharge temperature is low, the degree of change is reduced by ΔP. Maintain ΔT time at the intact degree and compare it with the second discharge temperature Td and the target temperature Ts. At this time, if the discharge temperature Td is higher than the target temperature Ts, the degree of change is increased by ΔP, and the degree of change before the increase is stored as the minimum degree of change Pmin. Similarly, the comparison between the discharge temperature Td and the target temperature Ts is repeated every? T time. When the discharge temperature Td is changed from a state higher than the target temperature Ts to a low state, that is, when the change in the degree of change is changed from ΔP amplification to ΔP decrease, the degree of change before ΔP decreases is determined by the maximum degree of change (Pmax). Remember as. When the maximum degree of change Pmax and the minimum degree of change Pmin are determined, the degree of change is changed to the average value (Pmax + Pmin) / 2.

When the output of the average displacement degree calculation means 14 is generated in this manner, temperature lines of Ts + ΔTh, Ts-ΔTh, Ts + ΔTT, and Ts-ΔTT are made on the plus side and the minus side of the target temperature Ts, respectively. . When the detected discharge temperature Td is below Ts + ΔTh and above Ts-ΔTh, the opening degree of the electric expansion valve is not changed. When it is less than Ts + ΔTT and higher than Ts + ΔTh, the correction amount calculating means 18 determines the correction amount ΔP (Td-Ts). Td).

From the output of this correction amount calculation means 18 and the output result of the average displacement degree calculation means 14, the displacement degree hunting table calculation means 19 sets average displacement degree, a is a positive integer and 0 <= b <1. As (a + b), it divides into an integer part and a fraction part. In addition, the holding time DELTA T (a) of the change degree (a) and the holding time DELTA T (a + 1) of the change degree (a + 1) are taken as DELTA T (a): ΔT (a + 1) = (1 -b): It is determined to be b, and the displacement degree output means 15 outputs the displacement degree (a) and the displacement degree (a + 1) repeatedly. When the discharge temperature Td is equal to or less than Ts + ΔTT and higher than Ts + ΔTh, this operation is repeated. That is, the correction amount calculating means 18 determines the correction amount DELTA P (Td-Ts), and when the correction amount DELTA T is less than Ts-DELTA or more than Ts- DELTA TT, the correction amount DELTA P (Ts-Td) is further determined. do.

For example, when the determined variation degree is 40.25, a = 40 and b = 0.25 are outputted by instructing a = 40 pulse for 45 seconds and a + 1 = 41 pulse for 15 seconds for a predetermined period of 60 seconds. In this 60-second period, the average variation is 40.25 degrees. The shifting degree hunting table calculating means creates a control pattern of the shifting degree and the indicating time of the opening degree.

The shift degree hunting table calculating means 19 creates a driving pattern as described above based on the average shift degree. Here, the hunting pattern may be prepared in advance based on the average degree of variation and stored in the memory, and the hunting table calculating means 19 may be configured to read it. And the displacement degree output means 15 controls an edge based on the pattern.

When the degree of change is less than or equal to the predetermined value, the degree of change output means 15 ignores the degree of change control instruction pattern output by the degree of change hunting table calculation means 19 described above. Then, based on the degree of change of (a + b) outputted by the average degree of change calculation means 14, the degree of change near any one of a or (a + 1) is selected and operated. The opening variable-variable expansion valve has a small influence on the flow rate of the change in the opening degree of one pulse at a predetermined opening from the expanded state, and also has a small influence on the state variation of the refrigeration cycle using the valve. However, the effect on the flow rate at the change of one pulse becomes large at the low opening degree near total closure. Based on this characteristic, the predetermined degree of change may be determined by an experiment or the like with an opening degree in a range in which the change in discharge temperature due to the change in the degree of change of one pulse sufficiently affects the temperature dead band.

According to the control method of the present embodiment having the above-described configuration, the degree of change is corrected with the degree of change correction area on the plus side and the minus side of the temperature dead band. This provides a refrigeration cycle with high efficiency and high stability even at low refrigerant flow rates. In addition, the intermediate flow rate of the pulse and the pulse is pseudo-generated by hunting the degree of change. As a result, a refrigeration cycle with high efficiency and high stability is provided even in an electric expansion valve having a large change in refrigerant flow rate of about one unit (1 pulse) of the degree of change. In addition, the calculation result of the degree of change is divided into a positive integer a and a decimal point b, the degree of change is determined as (a + b), and the holding time ΔT (a) and the degree of change of the degree of change (a) The hunting table is calculated so that the holding time DELTA T (a + 1) of (a + 1) is DELTA T (a): ΔT (a + 1) = (1-b): b. As a result, the refrigerant flow rate can be controlled in more detail, and a refrigeration cycle with high stability with high efficiency is provided.

In addition, in FIG. 1 which shows this embodiment, the structure which arrange | positions the discharge temperature sensor 5 in the vicinity of the compressor 1, and detects this temperature by the temperature detection means 7, was demonstrated, 2) or in the vicinity of the heat exchanger 4. In this case, the target temperature setting means 8 sets the temperature at which the temperature is controlled by the heat exchangers 2 and 4 (for example, air conditioning air and circulating water). This provides a thermostat with high temperature stability with high efficiency.

In addition, in this embodiment, although each means of the temperature comparison means 9-the degree of change output means 15 was demonstrated as each other, many of these may be comprised by an integrated semiconductor chip.

Claims (14)

A control device for controlling a refrigeration cycle configured with at least an opening variable variable valve, Temperature detection means for detecting a temperature at a predetermined point of the refrigeration cycle; Target temperature setting means for setting a target temperature of the refrigeration cycle; An area for correcting the degree of displacement on the plus side and the minus side of the temperature dead band which does not adjust the degree of change, which is set based on a comparison result between the temperature detected by the temperature detecting means and the target temperature set by the target temperature setting means, Generation degree correction area generating means for generating; And A control device for a refrigeration cycle, comprising a displacement degree correction amount calculating means for obtaining a correction amount from an output of a temperature detected by the temperature detecting means and a target temperature set by the target temperature setting means. The control apparatus for a refrigeration cycle according to claim 1, further comprising a change degree output means for adjusting the change degree based on a comparison result of a temperature detected by the temperature detection means and a target temperature determined by the target temperature setting means. 2. The apparatus according to claim 1, further comprising: a displacement degree calculation means for calculating a displacement degree based on a result of comparison between a temperature detected by the temperature detection means and a target temperature determined by the target temperature setting means; A maximum change degree calculating means for making the change degree immediately before the change to the closed action as the maximum change amount when the operation of the edge changes from the open action to the closed action; A minimum change degree calculating means for making the change degree immediately before changing to the open action as the minimum change amount when the operation of the edge changes from the closed action to the open action; And An average degree of change calculation unit for obtaining an average degree of change from the maximum degree of change and the minimum degree of change, and And a control device for a refrigeration cycle for outputting the average displacement degree calculation means to the displacement degree calculation means. 4. The control apparatus for a refrigeration cycle according to claim 3, further comprising a temperature dead band generating means for generating a temperature dead band when an output of said average change degree calculation means occurs. A control device for controlling a refrigeration cycle configured with at least a variable opening control valve, Temperature detecting means for detecting a temperature at a predetermined point of the refrigeration cycle; Target temperature setting means for setting a target temperature of the refrigeration cycle; Hunting table calculation means for hunting control of the degree of change; And Output of the degree of change of adjusting the degree of change by reflecting the calculation result of the hunting table calculation means in the degree of change determined based on a comparison result between the temperature detected by the temperature detecting means and the target temperature set by the target temperature setting means. A control device for a refrigeration cycle having a means. 6. The control apparatus for a refrigeration cycle according to claim 5, wherein said change degree output means ignores the calculation result of said hunting table calculation means when the change degree is less than a predetermined value. The said valve opening degree output means opens a predetermined amount when the detection temperature of the said temperature detection means is more than a target temperature, and closes a predetermined amount when the temperature of the said temperature detection means is less than a target temperature. The control unit of the refrigeration cycle to adjust the degree of change so that. 6. The hunting table calculating means according to claim 5, wherein the hunting table calculating means separates the calculation result pulse number of the degree of change into a positive integer a and the number of decimal places b, determines the degree of change as (a + b), and the degree of change (a). The holding time ΔT (a) and the holding time ΔT (a + 1) of the degree of change (a + 1) of ΔT (a): ΔT (a + 1) = (1-b): b A control device for a refrigeration cycle that performs calculation of a hunting table. As a control method for controlling a refrigeration cycle composed of a compressor, a heat exchanger, a stool, Detecting a temperature of a predetermined part of the refrigeration cycle; Setting a target temperature of the refrigeration cycle; Generating an area for correcting the degree of change on the plus side and the minus side of the temperature dead band without adjusting the degree of change set based on a result of the comparison between the detected temperature and the set target temperature; And And a step of obtaining a correction amount of the degree of change from the detected temperature and the set target temperature. As a control method for controlling a refrigeration cycle composed of a compressor, a heat exchanger, a stool, Detecting a temperature of a predetermined part of the refrigeration cycle; Setting a target temperature of the refrigeration cycle; Adjusting the degree of change based on a result of comparison between the detected temperature and the target temperature set by the target temperature setting means; And After determining in the step of adjusting the degree of change, the control method of the refrigeration cycle comprising the step of further hunting. The control method of a refrigeration cycle according to claim 10, wherein when the degree of change is less than or equal to a predetermined value, the step of hunting of the degree of change is ignored. The method of claim 10, wherein in the hunting of the degree of change, The calculation result of the degree of change is divided into a positive integer a and a number b after the decimal point, the degree of change is determined by (a + b), and the holding time ΔT (a) and the degree of change (a) of the degree of change (a) A control method of a refrigeration cycle in which a hunting table is calculated so that the holding time? T (a + 1) of +1) is? T (a):? T (a + 1) = (1-b): b. compressor; heat transmitter; side; And With control device, The control device is: Temperature detecting means for detecting a temperature at a predetermined place; Target temperature setting means for setting a target temperature; An area for correcting the degree of change on the plus side and the minus side of the temperature dead band without adjusting the degree of change, which is set based on a comparison result between the temperature detected by the temperature detecting means and the target temperature set by the target temperature setting means. Generation degree correction area generating means for generating; And And a displacement degree correction amount calculating means for obtaining a correction amount from an output of a temperature detected by said temperature detecting means and a target temperature set by said target temperature setting means. compressor; heat transmitter; side; And With control device, The control device, Temperature detection means for detecting a temperature at a predetermined location; Target temperature setting means for setting a target temperature; Hunting table calculation means for hunting the degree of change; And Output of the degree of change of adjustment of the degree of change by reflecting the calculation result of the hunting table calculation means in the degree of change determined based on a comparison result of the temperature detected by the temperature detecting means and the target temperature set by the target temperature setting means. Thermostat with means.