JPH0611172A - Cooling control device for multi-chamber type air conditioner - Google Patents

Abstract

PURPOSE:To prevent a room temperature from being disturbed and contrive an energy saving by a method wherein a degree of opening of an indoor electrical expansion valve and a frequency of a compressor having a variable capability are controlled in such a manner that over-heating and over-cooling of refrigerant are not produced. CONSTITUTION:The first target degree of opening of each of the indoor electrical expansion valves 27a to 27c is calculated by the first target degree of opening calculating means 32 in response to a deviation between the room temperatures detected by room temperature sensing means 29a to 29c and the target temperatures set by temperature setting means 30a to 30c. The second target degree of opening of each of the indoor electrical expansion valves 27a to 27c is calculated by the second target degree of opening calculating means 33 in response to a degree of over-heating of outlet pipes of the indoor heat exchangers 31a to 31c detected by the over-heating degree sensing means 28a to 28c. A fuzzy inference is carried out in response to these results, over-heating degrees detected by the over-heating degree sensing means 28a to 28c and a control rule taken out of the memory device 35 and then the degree of opening of each of the indoor electrical expansion valves 27a to 27c is determined in response to the result of the inference. A frequency of each of the compressors 22a and 22b having a variable capability is determined by comparing it with the predetermined frequency. With such an arrangement as above, each of the indoor units is controlled in response to the most-suitable degree of opening and the most-suitable frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner for controlling the air conditioning capacity of each indoor unit by controlling the opening degree of an indoor electric expansion valve and the frequency control of a capacity variable compressor in a plurality of outdoor units. In regard to the above, the present invention relates to a cooling control device capable of smoothly controlling the room temperature of each indoor unit without disturbance and saving energy of the equipment.

[0002]

2. Description of the Related Art In recent years, in a building air conditioner, an indoor unit is installed in each room for a plurality of rooms having different loads, and a multi-room type air conditioner connecting this to one outdoor unit is used for each room. Many individual distributed air conditioning systems are used.

Under such circumstances, conventionally, Japanese Patent Laid-Open No. 63-1
An air conditioner provided with a variable capacity compressor as disclosed in Japanese Patent No. 80051 is known.

A conventional technique will be described below with reference to the drawings. FIG. 4 is a block diagram of a conventional cooling control device for a multi-room air conditioner. In FIG. 4, in a multi-room air conditioner in which a variable capacity compressor 1, a condenser 2, an electric expansion valve 3 and an evaporator 4 are sequentially connected to form a refrigerant circulation system 5, a room temperature detecting means for detecting room temperature. 6, and a target opening degree calculating means 7 for receiving the output of the room temperature detecting means 6 and calculating a target opening degree of the indoor electric expansion valve 3 according to a deviation between a room temperature and a room temperature target value; An opening degree control means 8 for controlling the opening degree of the indoor electric expansion valve 3 to a target opening degree, an overheat degree detecting means 9 for detecting the degree of superheat of the refrigerant, and the opening degree control means 8 in response to the output of the computing means 7. It comprises a protection means 10 which takes precedence over.

The operation of the conventional cooling control apparatus for a multi-room air conditioner configured as described above will be described below. First, during the air conditioning operation, the target opening degree of the indoor electric expansion valve 3 according to the deviation between the room temperature and the room temperature target value is calculated by the target opening calculation means 7, and the indoor electric expansion valve is adjusted to this target opening. Since the opening degree 3 is controlled to be increased / decreased by the opening degree control means 8, the flow rate of the refrigerant to the evaporator 4 becomes an appropriate amount, the air conditioning load and the air conditioning capacity in the room correspond well, and the room becomes comfortable. Air-conditioned.

[0006] Now, for example, when the air-conditioning load in the room decreases and the superheat degree of the refrigerant decreases, when the superheat degree of the refrigerant is received and the superheat degree of the refrigerant is below a predetermined superheat degree value for wet operation, The opening degree of the indoor electric expansion valve 3 is reduced by the protection means 10 prior to the opening degree control means 8. Therefore, the degree of superheat of the refrigerant increases, and as a result, the occurrence of a wet state of the refrigerant is effectively prevented.

[0007]

However, in such a configuration, the opening degree of each indoor electric expansion valve 3 is controlled individually, so that depending on the operation of the indoor electric expansion valve 3, the refrigerant to another indoor unit may be changed. Due to an excess or deficiency of the amount, the variable capacity compressor 1 had to change the frequency with a time delay.

Further, since the control method of the opening degree of the indoor electric expansion valve 3 largely changes at the predetermined superheat value as a boundary, there is a problem that the room temperature is disturbed near the boundary.

In order to solve the above problems, the present invention controls the indoor electric expansion valve opening and the variable capacity compressor frequency so that the degree of superheat of the refrigerant does not rise or fall too much, thereby disturbing the room temperature. It is an object of the present invention to provide a cooling control device for a multi-room air conditioner, which is capable of preventing the above and improving comfort and energy saving.

[0010]

In order to solve the above problems, a cooling control device for a multi-room air conditioner according to the present invention comprises a room temperature detecting means for detecting room temperature, a temperature setting means for setting a target temperature, First target opening degree calculating means for calculating a first target opening degree of the indoor electric expansion valve based on a deviation between a room temperature detected by the room temperature detecting means and a target temperature set by the temperature setting means; A superheat degree detecting means for detecting a superheat degree of each indoor heat exchanger outlet pipe; and a second target opening degree for calculating the second target opening degree of the indoor electric expansion valve based on the superheat degree detected by each superheat degree detecting means. 2 target opening degree calculation means.

Further, according to an empirical rule for obtaining the optimum opening degree of each indoor electric expansion valve from the first and second target opening degrees with respect to the superheat degree detected by each of the superheat degree detecting means. A memory device for storing a control rule based on the above; first and second target opening degrees respectively calculated by the first and second target opening degree calculating means; Fuzzy inference means for performing a fuzzy logic operation based on a control rule extracted from the memory device, and an opening degree for determining the optimum opening degree of each indoor electric expansion valve based on the inference result performed by the fuzzy inference means It is characterized by comprising a determining means and a frequency determining means for determining the frequency of the variable capacity compressor by comparing with a preset frequency based on the inference result obtained by the fuzzy inference means.

[0012]

The cooling control device for a multi-room air conditioner according to the present invention has the above-mentioned configuration, and calculates the first target opening degree based on the deviation between the room temperature detected by the room temperature detecting means and the target temperature set by the temperature setting means. Means for calculating the first target opening degree of the indoor electric expansion valve, and second target opening degree calculating means based on the superheat degree detected by the superheat degree detecting means for detecting the superheat degree of the indoor heat exchanger outlet pipe. Then, the second target opening degree of the indoor electric expansion valve is calculated.

Based on these results, the degree of superheat detected by the degree of superheat detection means, and the fuzzy inference based on the control rule based on the empirical rule extracted from the memory device, based on the inference result obtained by the fuzzy inference means Since the frequency of the expansion valve is determined and the frequency determining means for determining the frequency of the variable capacity compressor by comparing it with a preset frequency, each indoor unit can always be controlled with the optimal opening and frequency. It is possible to prevent excess and deficiency of the amount of refrigerant in the indoor unit of
The frequency of the variable capacity compressor can be changed without time delay. As a result, the room temperature can be prevented from being disturbed, comfort can be improved, and energy can be saved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling control device for a multi-room air conditioner according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a cooling control device for a multi-room air conditioner according to the present invention. In FIG. 1, 21a, 21
Reference numeral b is an outdoor unit, which is a variable capacity compressor 22a,
22b, outdoor heat exchangers 23a and 23b, outdoor electric expansion valves 24a and 24b, and four-way valves 25a and 25b. Reference numerals 26a, 26b and 26c denote indoor units, which are indoor electric expansion valves 27a, 27b and 27c, superheat detection means (to be described later) 28a, 28b and 28c, room temperature detection means 29a, 29b and 29c and temperature setting means 30, respectively.
a, 30b, 30c and indoor heat exchangers 31a, 31b,
31c.

Reference numerals 28a, 28b and 28c are superheat detecting means, which are installed in the pipes connecting the indoor heat exchangers 31a, 31b and 31c and the indoor electric expansion valves 27a, 27b and 27c, respectively. Reference numeral 32 denotes a first target opening degree calculation means for calculating a first target opening degree of each indoor electric expansion valve 27 from the deviation between the room temperature detected by the room temperature detection means 29 and the target temperature set by the temperature setting means 30. is there. Reference numeral 33 denotes each indoor electric expansion valve 2 based on the degree of superheat detected by each degree of superheat detection means 28.
7 is a second target opening degree calculating means for calculating the second target opening degree 7.

Reference numeral 34 is a microprocessor, which comprises a memory device 35 for storing control rules and fuzzy inference means 36. Reference numeral 37 is an opening degree determining means for determining the opening degree of each indoor electric expansion valve 27 based on the result obtained by the fuzzy inference means 36, and 38 is each capacity variable according to the opening degree instruction determined by the opening degree determining means 37. The frequency determining means controls the frequency of the compressor 22.

The operation of the cooling control device for a multi-room air conditioner configured as described above will be described.

The deviation between the room temperature detected by the room temperature detecting means 29 and the target temperature set by the temperature setting means 30 is obtained, and the first target opening degree calculating means 32 calculates the first target opening degree S1 from the deviation. . Further, the second target opening degree computing means 33 calculates the second target opening degree S2 from the superheat degree SH detected by the superheat degree detecting means 28.

The first target opening degree S1, the second target opening degree S2, and the superheat degree SH detected by the superheat degree detecting means 28 calculated as described above are input to the fuzzy inference means 36. The memory device 35 stores the control rules necessary for the fuzzy inference executed by the fuzzy inference means 36. Fuzzy inference is executed based on the following control rules.

The control rules adopted in this embodiment are the following three rules. Rule R1: If the degree of superheat is small, the degree of opening is the second target degree of opening Rule R2: If the degree of superheat is medium, the degree of opening is the first target degree of opening Rule R3: If the degree of superheat is large If so, the opening is the second target opening. The language rule is a control rule for determining the opening of the indoor electric expansion valve, which is obtained from the empirical rule obtained by the inventor from many experimental data. This is shown in Table 1 (Table 1).

[0022]

[Table 1]

Table 1 shows the relationship of control rules for determining the opening degree of the variable capacity compressor 22 used in the embodiment. (Table 1) shows 3 depending on the degree of superheat SH in the lateral direction.
It is arranged in stages (S = small, M = medium, B = large), and the opening F of the variable capacity compressor 22 with respect to the size of the divided superheat degree SH is set.

Here (Table 1), there are two stages (S1 = first target opening, S2 = second target opening) according to the opening (F) of the variable capacity compressor 22. . That is, the control rule Ri (i = 1, 2, 3) is indicated by a square (Ri) in (Table 1).

The language rules are stored according to the following rules when stored in the memory device 35 of FIG. The number of control rules used here is three. Rule R1: IF SH is S THEN F = S
2 Rule R2: IF SH is M THEN F = S
1 Rule R3: IF SH is B THEN F = S
2. Next, the fuzzy inference means 36 retrieves the control rule stored in advance in the memory device 35 and calculates the opening of each indoor electric expansion valve 27 by fuzzy inference.

The control rules R1, R2, and R3 are the variable capacity compressor 22 with respect to the superheat degree SH.
Since the opening degree of the control rule is determined stepwise, when performing fine control, the degree to which the antecedent part (IF part) of the control rule is satisfied is calculated, and the degree is determined according to the degree. It is necessary to determine the opening degree of each indoor electric expansion valve 27. Therefore, in this embodiment, a membership function of fuzzy variables is used to calculate the degree.

FIG. 2 shows membership functions μS (SH) and μM (S) of fuzzy variables S, M and B with respect to the superheat degree SH.
H) and μB (SH).

The fuzzy inference executed by the fuzzy inference means 36 uses the control rules R1, R2 and R3 and the membership function of FIG.
The opening degree 7 is calculated. The inference procedure will be described below with reference to FIG.

FIG. 3A is a flow chart showing the inference procedure. In STEP 1, the deviation between the room temperature detected by the room temperature detecting means 29 and the target temperature set by the temperature setting means 30 is calculated,
From this deviation, the first target opening degree calculation means 32 calculates the first target opening degree S1. In STEP2, the second target opening degree computing means 33 calculates the second target opening degree S2 from the superheat degree SH detected by the superheat degree detecting means 28.

In STEP 3, the fuzzy inference means 36 uses the membership function of the fuzzy variable for the superheat degree SH to calculate the membership value at the superheat degree SH. In STEP 4, the degree to which the obtained membership value belongs to the antecedent part of each of the three rules is calculated.

Next, the opening degree determining means 37 opens the mixture ratio of the first target opening degree S1 and the second target opening degree S2 based on the degree of belonging determined in STEP 4 of the fuzzy reasoning described above. The degree is determined, and the indoor expansion valve 27 is controlled.

Next, the frequency determining means 38 responds to the mixture ratio of the first target opening S1 and the second target opening S2 based on the degree of belonging determined in STEP 4 of the fuzzy inference described above. The preset frequency is determined and each variable capacity compressor 22 is controlled.

For example, as shown in FIG. 3 (b), the degree of superheat S
If H is SH1, 50% for control rules R2 and R3
Belong to each. Therefore, the opening degree F is obtained by (Equation 1).

[0034]

[Equation 1]

According to the configuration of the above embodiment, when the superheat degree SH has an appropriate magnitude, the deviation between the room temperature and the target temperature is used as a control parameter, so that each room is optimal depending on the magnitude of the air conditioning load. The opening degree of the inner electric expansion valve 27 can be controlled. When the superheat degree SH is too large or too small, the superheat degree SH is used as a control parameter.
It is possible to optimally control the opening degree of each indoor electric expansion valve 27 according to the magnitude of H, and it is possible to perform air conditioning operation with an appropriate degree of superheat.

Further, when the superheat degree SH is in the middle between proper and excessive or proper and small, it is possible to finely and smoothly control the opening degree of each indoor electric expansion valve 27 by fuzzy reasoning.

Further, in each capacity variable compressor 22,
When the mixing ratio of the first target opening S1 and the second target opening S2 belongs to 50% each, the frequency is set to 50% of each maximum capacity and the frequency preset from the experimental value. Then, the variable capacity compressor 22 is controlled. As a result, the frequency of each variable capacity compressor is already set at the end of setting the target opening degree of each indoor electric expansion valve 27, so that the frequency can be changed without time delay. As a result, the room temperature can be prevented from being disturbed, comfort can be improved, and energy can be saved.

[0038]

As is apparent from the above embodiments, the cooling control device for a multi-room air conditioner according to the present invention comprises a room temperature detecting means for detecting room temperature, a temperature setting means for setting a target temperature,
First target opening degree calculating means for calculating a first target opening degree of the indoor electric expansion valve based on a deviation between a room temperature detected by the room temperature detecting means and a target temperature set by the temperature setting means; A superheat degree detecting means for detecting a superheat degree of each indoor heat exchanger outlet pipe; and a second target opening degree for calculating the second target opening degree of the indoor electric expansion valve based on the superheat degree detected by each superheat degree detecting means. Two target opening degree calculation means are provided.

Further, in accordance with the empirical rule for obtaining the optimum opening degree of each indoor electric expansion valve from the first and second target opening degrees with respect to the superheat degree detected by each superheat degree detecting means. A memory device for storing a control rule based on the above; first and second target opening degrees respectively calculated by the first and second target opening degree calculating means; Fuzzy inference means for performing a fuzzy logic operation based on a control rule extracted from the memory device, and an opening degree for determining the optimum opening degree of each indoor electric expansion valve based on the inference result performed by the fuzzy inference means By the determining means and the frequency determining means for determining the frequency of the variable capacity compressor by comparing with the preset frequency based on the result of the inference performed by the fuzzy inference means, the optimum opening and frequency are always maintained. Can be controlled indoor unit,
It is possible to prevent excess and deficiency of the refrigerant amount to other indoor units, and it is possible to change the frequency of the variable capacity compressor without delay. As a result, the room temperature can be prevented from being disturbed, comfort can be improved, and energy can be saved.

[Brief description of drawings]

FIG. 1 is a block diagram of a cooling control device for a multi-room air conditioner according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing membership functions of fuzzy variables S, M and B with respect to superheat degree SH.

3 (a) is a flow chart showing an inference procedure. FIG. 3 (b) is a fuzzy variable S, M, B for the superheat degree SH1.
Characteristic diagram showing the degree of belonging of

FIG. 4 is a block diagram of a conventional cooling control device for an air conditioner.

[Explanation of symbols]

 21a, 21b outdoor unit 22a, 22b variable capacity compressor 23a, 23b outdoor heat exchanger 24a, 24b outdoor electric expansion valve 25a, 25b four-way valve 26a, 26b, 26c indoor unit 27a, 27b, 27c indoor electric expansion valve 28a, 28b, 28c Superheat detection means 29a, 29b, 29c Room temperature detection means 30a, 30b, 30c Temperature setting means 31a, 31b, 31c Indoor heat exchanger 32 First target opening calculation means 33 Second target opening Degree calculation means 35 Memory device 36 Fuzzy inference means 37 Opening degree determination means 38 Opening degree control means

Claims (1)

[Claims] 1. A plurality of outdoor units including a variable capacity compressor, a four-way valve, an outdoor heat exchanger, and an outdoor electric expansion valve; an indoor electric expansion valve and an indoor heat exchanger; In a multi-room air conditioner composed of a plurality of indoor units connected in parallel to the unit, room temperature detecting means for detecting room temperature, temperature setting means for setting a target temperature, and room temperature detected by the room temperature detecting means And first target opening degree calculating means for calculating a first target opening degree of the indoor electric expansion valve based on a deviation between the target temperature set by the temperature setting means and each indoor heat exchanger outlet pipe And a second target opening degree calculating means for calculating a second target opening degree of the indoor electric expansion valve based on the superheat degree detected by each of the superheat degree detecting means. , The temperature detected by each of the superheat detection means A memory device for storing a control rule based on an empirical rule for obtaining an optimal opening degree of each indoor electric expansion valve from the first and second target opening degrees with respect to heat value; Fuzzy logic operation based on the first and second target opening degrees respectively calculated by the target opening degree calculating means, the superheat degree detected by the respective superheat degree detecting means, and the control rule extracted from the memory device. Fuzzy inference means to perform, opening degree determining means for determining the optimal opening degree of each indoor electric expansion valve based on the inference result performed by the fuzzy inference means, and in advance based on the inference result performed by the fuzzy inference means A cooling control device for a multi-room air conditioner, comprising: frequency determining means for determining a frequency of the variable capacity compressor in comparison with a set frequency.