JP3174153B2 - Cooling control device for multi-room air conditioner - Google Patents

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 in a plurality of outdoor units by controlling the opening of an indoor electric expansion valve and controlling the frequency of a variable capacity compressor. The present invention relates to a cooling control device capable of smoothly controlling the room temperature of each indoor unit without disturbing and saving energy of equipment.

[0002]

2. Description of the Related Art In recent years, in a building air conditioner, an indoor unit is installed for each of a plurality of rooms having different loads, and each room is connected to a single outdoor unit by a multi-room air conditioner. Individually distributed air conditioning is frequently performed.

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

[0004] The prior art will be described below with reference to the drawings. FIG. 4 shows 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, room temperature detecting means for detecting room temperature. 6, a target opening calculating means 7 for receiving the output of the room temperature detecting means 6 and calculating a target opening of the indoor-side electric expansion valve 3 according to a deviation between the room temperature and the target room temperature; The opening control means 8 receives the output of the calculating means 7 and controls the opening of the indoor-side electric expansion valve 3 to the target opening, the superheat detection means 9 for detecting the superheat of the refrigerant, and the opening control means 8 And protection means 10 which has priority over

The operation of the conventional cooling control device for a multi-room air conditioner configured as described above will be described below. First, during the air-conditioning operation, the target opening 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 calculating means 7, and the indoor electric expansion valve is set so as to reach this target opening. 3 is controlled to be increased or decreased by the opening control means 8, so that the flow rate of the refrigerant to the evaporator 4 becomes an appropriate amount, and the indoor air-conditioning load and the air-conditioning capacity are satisfactorily corresponded to make the room comfortable. Air-conditioned.

Now, for example, when the degree of superheating of the refrigerant decreases due to a decrease in the air conditioning load in the room, the output of the superheating degree detecting means 9 is received. The opening degree of the indoor-side electric expansion valve 3 is reduced by the protection means 10 prior to the opening degree control means 8. Accordingly, the degree of superheat of the refrigerant is increased, 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-side electric expansion valve 3 is individually controlled. Therefore, depending on the operation of the indoor-side electric expansion valve 3, the refrigerant to other indoor units may be removed. An excess or deficiency occurred, and the variable capacity compressor 1 had to change the frequency with a time delay.

In addition, since the control method of the opening degree of the indoor electric expansion valve 3 is greatly changed with a predetermined superheat degree as a boundary, there is a problem that the room temperature is disturbed near the boundary.

In order to solve the above-mentioned problems, the present invention controls the opening degree of the indoor-side electric expansion valve and the frequency of the variable capacity compressor so that the degree of superheat of the refrigerant does not increase or decrease excessively. It is an object of the present invention to provide a cooling control device for a multi-room air conditioner, which can prevent the air conditioner, improve the comfort and save energy.

[0010]

According to the present invention, there is provided a cooling control apparatus for a multi-room air conditioner, comprising: a room temperature detecting means for detecting a room temperature; a temperature setting means for setting a target temperature; First target opening calculating means for calculating a first target opening of the indoor electric expansion valve based on a deviation between the room temperature detected by the room temperature detecting means and the 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 of the indoor electric expansion valve based on the superheat degree detected by each superheat degree detecting means. And two target opening calculating means.

Further, an empirical rule for obtaining an optimum opening of each of the indoor side electric expansion valves from the first and second target openings with respect to the degree of superheat detected by the respective degree of superheat detection means. A memory device that stores a control rule based on the first and second target opening degrees calculated by the first and second target opening degree calculating means, and a superheat degree detected by the respective superheat degree detecting means. Fuzzy inference means for performing a fuzzy logic operation based on a control rule extracted from the memory device, and an opening for determining an optimal opening of each of the indoor-side electric expansion valves based on an inference result performed by the fuzzy inference means. Determining means, and frequency determining means for determining a frequency of the variable capacity compressor based on a result of the inference performed by the fuzzy inference means and comparing the frequency with a preset frequency.

[0012]

According to the cooling control device for a multi-room air conditioner of the present invention, a first target opening degree is calculated 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 a first target opening of the indoor-side electric expansion valve, and a second target opening calculating means based on the degree of superheat detected by the degree of superheat detecting means for detecting the degree of superheat of the outlet pipe of the indoor heat exchanger. Calculates the second target opening degree of the indoor-side electric expansion valve.

Based on these results, the degree of superheat detected by the degree of superheat detection means, and a control rule based on empirical rules taken out of the memory device, fuzzy inference is performed. The determination of the opening of the expansion valve and the frequency determination means for determining the frequency of the variable capacity compressor by comparing the frequency with a preset frequency make it possible to always control each indoor unit with the optimal opening and frequency. The amount of refrigerant in the indoor unit can be prevented from being excessive or insufficient,
The frequency of the variable capacity compressor can be changed without time delay. As a result, disturbance of room temperature is prevented, and comfort can be improved and energy can be saved.

[0014]

DETAILED 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
b is an outdoor unit, each of which has 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. 26a, 26b, 26c are indoor units, which are indoor-side electric expansion valves 27a, 27b, 27c, superheat degree detection means (described later) 28a, 28b, 28c, room temperature detection means 29a, 29b, 29c, and temperature setting means 30, respectively.
a, 30b, 30c and the indoor heat exchangers 31a, 31b,
31c.

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

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

A 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 a first target opening degree S1 is calculated from the deviation by the first target opening degree calculating means 32. . Further, a second target opening degree S2 is calculated by the second target opening degree calculating means 33 from the superheat degree SH detected by the superheat degree detecting means 28.

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

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

[0022]

[Table 1]

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

Here, in 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
Next, the fuzzy inference means 36 takes out the control rules stored in the memory device 35 in advance and calculates the opening degree of each indoor expansion valve 27 by fuzzy inference.

The rules of the control rules R1, R2 and R3 are based on the variable capacity compressor 22 for the superheat degree SH.
The degree of opening is determined in a stepwise manner. In order to perform fine control, the degree to which the antecedent part (IF part) of the control rule is satisfied is calculated, and the degree corresponding to the degree is calculated. It is necessary to determine the opening of each indoor expansion valve 27. Therefore, in this embodiment, a membership function of a fuzzy variable is used to calculate the degree.

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

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

FIG. 3A is a flowchart showing the inference procedure. In STEP1, a 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.
The first target opening degree S1 is calculated from the deviation by the first target opening degree calculating means 32. In Step 2, the second target opening degree S2 is calculated by the second target opening degree calculating means 33 from the superheat degree SH detected by the superheat degree detecting means 28.

In STEP 3, the membership value at the superheat degree SH is calculated by the fuzzy inference means 36 using the fuzzy variable membership function for 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, based on the degree of affiliation obtained in STEP 4 of the fuzzy inference described above, the opening degree determining means 37 determines the opening degree from the mixture ratio of the first target opening degree S1 and the second target opening degree S2. The degree is determined, and control of each indoor-side electric expansion valve 27 is performed.

Next, the frequency determining means 38 corresponds to the mixing ratio of the first target opening S1 and the second target opening S2 based on the degree of affiliation obtained in STEP 4 of the fuzzy inference described above. The frequency set in advance is determined, and each variable capacity compressor 22 is controlled.

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

[0034]

(Equation 1)

According to the configuration of the above embodiment, when the degree of superheat SH is an appropriate value, the deviation between the room temperature and the target temperature is used as a control parameter. 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, so that the superheat degree S
Optimal opening control of each indoor-side electric expansion valve 27 can be performed according to the magnitude of H, and air-conditioning operation can be performed with an appropriate degree of superheat.

When the degree of superheat SH is between the appropriate and excessive or between the appropriate and excessive, the opening degree of each indoor-side electric expansion valve 27 can be finely and smoothly controlled by fuzzy inference.

Further, in each capacity variable compressor 22,
When the mixture 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 a frequency set in advance from an experimental value. After the determination, the variable capacity compressor 22 is controlled. Thereby, the frequency of each variable capacity compressor is already set when the target opening degree of each indoor electric expansion valve 27 is set, so that the frequency can be changed without time delay. As a result, disturbance of room temperature is prevented, and comfort can be improved and energy can be saved.

[0038]

As is apparent from the above embodiments, the cooling control apparatus for a multi-room air conditioner according to the present invention comprises: a room temperature detecting means for detecting a room temperature; a temperature setting means for setting a target temperature;
First target opening calculating means for calculating a first target opening of the indoor electric expansion valve based on a deviation between the room temperature detected by the room temperature detecting means and the 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 of the indoor electric expansion valve based on the superheat degree detected by each superheat degree detecting means. 2 target opening calculating means.

Further, an empirical rule for obtaining an optimum opening of each of the indoor-side electric expansion valves from the first and second target openings with respect to the degree of superheat detected by the respective degree of superheat detection means. A memory device that stores a control rule based on the first and second target opening degrees calculated by the first and second target opening degree calculating means, and a superheat degree detected by the respective superheat degree detecting means. Fuzzy inference means for performing a fuzzy logic operation based on a control rule extracted from the memory device, and an opening for determining an optimal opening of each of the indoor-side electric expansion valves based on an inference result performed by the fuzzy inference means. Determining means, and frequency determining means for determining the frequency of the variable capacity compressor by comparing the frequency with a preset frequency based on the inference result performed by the fuzzy inference means, always with the optimum opening degree and frequency. Can be controlled indoor unit,
Excess or deficiency of the refrigerant amount to other indoor units can be prevented, and the frequency of the variable capacity compressor can be changed without time delay. As a result, disturbance of room temperature is prevented, and comfort can be improved and energy can be saved.

[Brief description of the 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 a membership function of fuzzy variables S, M, and B with respect to a superheat degree SH.

FIG. 3A is a flowchart showing an inference procedure. FIG. 3B is a flowchart showing fuzzy variables S, M and B with respect to a superheat degree SH1.
Characteristic chart showing the degree of affiliation

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 degree detecting means 29a, 29b, 29c Room temperature detecting means 30a, 30b, 30c Temperature setting means 31a, 31b, 31c Indoor heat exchanger 32 First target opening calculating means 33 Second target opening Degree calculation means 35 Memory device 36 Fuzzy inference means 37 Opening degree determining means 38 Opening degree controlling means

Claims (1)

(57) [Claims] A plurality of outdoor units each comprising 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 comprising a plurality of indoor units connected in parallel to a unit, a room temperature detecting means for detecting a room temperature, a temperature setting means for setting a target temperature, and a room temperature detected by the room temperature detecting means. Target opening degree calculating means for calculating a first target opening degree of the indoor-side electric expansion valve based on a deviation between the target temperature set by the temperature setting means and the indoor-side heat exchanger outlet piping. Superheat degree detection means for detecting the degree of superheat, and second target opening degree calculation means for calculating a second target opening degree of the indoor-side electric expansion valve based on the degree of superheat detected by each of the superheat degree detection means. The superheat detected by each of the superheat detection means. A memory device for storing a control rule based on an empirical rule for determining an optimum opening of each of the indoor-side electric expansion valves from the first and second target openings with respect to a degree of heat; The fuzzy logic operation is performed based on the first and second target openings calculated by the target opening calculating means, the superheat detected by the respective superheat detecting means, and the control rule extracted from the memory device. Fuzzy inference means to be performed, opening degree determination means for determining an optimal opening degree of each indoor side electric expansion valve based on the inference result performed by the fuzzy inference means, and advance determination based on the inference result performed by the fuzzy inference means. A frequency control means for determining a frequency of the variable capacity compressor in comparison with a set frequency.