JP2502831B2 - 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 control of opening degree of each indoor expansion valve and compressor rotation speed in a multi-room air conditioner.

[0002]

2. Description of the Related Art FIG. 7 is a system configuration diagram of a conventional multi-room air conditioner, in which 1 is a compressor, 2 is a four-way valve for switching heating / cooling cycles, 3 is an outdoor heat exchanger, 4 is a receiver, and 5 is a receiver.
Is an accumulator and is provided in the outdoor unit 6.
Each of the indoor units 7A, 7B, 7C has an indoor heat exchanger 8A, 8A.
B, 8C, indoor expansion valves 9A, 9B, 9C, room temperature detector 1
0A, 10B, 10C, each room 11A, 11B,
11C, the outdoor unit 6 and the indoor units 7A, 7
The gas side of B and 7C and the liquid side are respectively connected to the gas side pipeline 12,
And a liquid side conduit 13 to form a closed circuit, the gas side conduit 12 is provided with a pressure detector 14, and a refrigerant is sealed inside the closed circuit, which is a known heat pump cycle.

The mode of operation of the multi-room air conditioner having such a configuration will be described below. During the heating operation, as shown by the solid line in FIG. 7, the refrigerant is compressed in the compressor 1 to become high-temperature and high-pressure vapor, which is discharged through the four-way valve 2 to the gas side conduit 12 and the indoor units 7A and 7B. , Indoor heat exchanger 8 in 7C
A, 8B, 8C. At this time, each indoor heat exchanger 8
A, 8B and 8C act as condensers, and each room 11A, 1A
Each room 11 by applying heat to the air of 1B, 11C
Heating A, 11B, and 11C, the refrigerant is condensed and liquefied. The liquefied refrigerant reaches the outdoor heat exchanger 3 through the indoor expansion valves 9A, 9B, 9C, the liquid side conduit 13 and the receiver 4. At this time, the outdoor heat exchanger 3 functions as an evaporator, receives heat from the outside air to evaporate, becomes low-pressure vapor, and is sucked into the compressor 1 through the four-way valve 2 and the accumulator 5.

During the cooling operation, as shown by the broken line in FIG. 7, by switching the four-way valve 2, the outdoor heat exchanger 3 functions as a condenser, and the indoor heat exchangers 8A, 8B, 8C function as evaporators, and each room 1
By absorbing heat from the air of 1A, 11B, 11C,
Each room 11A, 11B, 11C is cooled.

Next, the mode of operation of each indoor expansion valve 9A, 9B, 9C will be described below. Each indoor expansion valve 9A, 9B, 9
When the opening degree of C is increased, the flow rate of the refrigerant is increased, and the room temperature of each room 11A, 11B, 11C is increased during the heating operation,
Conversely, during cooling operation, the temperature decreases, and the temperature of each room temperature detector 1
It is detected by 0A, 10B, and 10C.

The mode of operation of the compressor 1 will be described below. When the number of rotations of the compressor 1 is increased, the flow rate of the refrigerant is increased, and the gas side pipeline 12 becomes a high pressure gas pipeline during the heating operation.
The refrigerant pressure rises, and the refrigerant pressure in the gas side pipeline 12, which is the low-pressure gas pipeline during the cooling operation, decreases, and the pressure is detected by the pressure detector 14.

In such a multi-room air conditioner, the room temperature is controlled according to the load of each room 11A, 11B, 11C,
It is necessary to control the pressure, which is the state quantity of the cycle that reflects the total load.

FIG. 8 is a control block configuration diagram of each indoor expansion valve and compressor of the conventional multi-room air conditioner. Each room temperature controller 15A, 15B, 15C and pressure controller 16 are
Room temperature setters 17A, 17B, 17C for setting the target values of the room temperatures of the rooms 11A, 11B, 11C, and a pressure setter 18 for setting the target value of the pressure and the room temperature detectors 10A,
10B, 10C and subtractors 19A, 19B, 19C, 19D for outputting the difference between the outputs from the pressure detector 14 and integrators 20A, 20B for integrating the respective outputs from the subtracters 19A, 19B, 19C, 19D. , 20C, 20D and differentiators 21A, 21B, 21C, 21D, 22A, 22 for differentiating the respective outputs of the subtracters 19A, 19B, 19C, 19D.
B, 22C and 22D are proportional coefficient setting devices, 23A and 23
B, 23C and 23D are the respective integral coefficient setting units, 24A and 24
B, 24C and 24D are differential coefficient setting units, 25A and 25
B, 25C and 25D are subtractors 19A, 19B and 19
C, 19D and each proportional coefficient setting device 22A, 22
The first multipliers 26A, 26B, 26C, and 26D that output the products of the outputs of B, 22C, and 22D are the integrators 20.
Each second multiplier 27A, 27B, 27C, 27D that outputs the product of each output of A, 20B, 20C, 20D and each output of each integration coefficient setter 23A, 23B, 23C, 23D.
Is a third multiplier and a first multiplier 25 that output the products of the outputs of the differentiators 21A, 21B, 21C, 21D and the outputs of the differential coefficient setters 24A, 24B, 24C, 24D.
A, 25B, 25C, 25D, each second multiplier 26A, 2
6B, 26C, 26D, and each third multiplier 27A, 27
B, 27C, 27D, each adder 28A,
8B, 28C, 28D, and adders 28A, 28
B, 28C, 28D outputs are used to expand each indoor expansion valve 9
This is a so-called PID controller that controls the opening degrees of A, 9B, and 9C and the rotation speed of the compressor 1.

The operation modes of the room temperature controller and the pressure controller in such a configuration will be described below. When the load of each room 11A, 11B, 11C increases during cooling operation, the room temperature rises and is detected by each room temperature detector 10A, 10B, 10C,
Each of the room temperature controllers 15A, 15B, 15 is adjusted to match the room temperature set by each of the room temperature setting devices 17A, 17B, 17C.
At C, the opening degree of each indoor expansion valve 9A, 9B, 9C is increased. As a result, the pressure difference around each of the indoor expansion valves 9A, 9B, 9C decreases, the refrigerant pressure rises, and the pressure control is performed so that the pressure is detected by the pressure detector 14 and coincides with the pressure set by the pressure setter 18. The rotation speed of the compressor 1 is increased in the container 16. That is, the number of rotations of the compressor 1 is 1
It will change by an amount commensurate with the total value of the loads of 1B and 11C. Here, each room temperature controller 15A, 15B, 15
C, and each proportional coefficient setting unit 22A, 2
2B, 22C, 22D, respective integration coefficient setters 23A, 23
B, 23C, 23D, and each differential coefficient setting device 24A, 2
4B, 24C, and 24D are set to the indoor expansion valve 9A,
Room temperature detectors 10A, 1 for changes in opening of 9B, 9C
0B, 10C output changes, and when appropriately set according to the characteristics of the output change of the pressure detector 14 with respect to the rotational speed change of the compressor 1, each room temperature detector 10A, with appropriate response.
The outputs of 10B, 10C, and the pressure detector 14 match the outputs of the room temperature setters 17A, 17B, 17C, and the pressure setter 18, respectively.

[0010]

However, in such a multi-chamber air conditioner, each indoor expansion is performed only by the output of each of the room temperature detectors 10A, 10B and 10C irrespective of the degree of superheat of the suction portion of the compressor 1. Since the opening degree of the valves 9A, 9B, 9C is operated, when the room temperature set value is changed, the opening degree of each indoor expansion valve 9A, 9B, 9C changes, and the degree of superheat becomes too small or too large, and each room temperature is detected. Vessels 10A, 10B, 10
Even if the output of C matches the room temperature set value, that is, even at the time of equilibrium, the degree of superheat becomes too large or too small depending on the relationship with the load of each room 11A, 11B, 11C, and the output of each room temperature detector 10A, 10B, 10C. Since the rotation speed of the compressor 1 is operated only by the output of the pressure detector 14 regardless of the above, the rotation speed of the compressor 1 becomes too small or too large with respect to the load of each room 11A, 11B, 11C, and each room temperature detector. The compressors 1A, 10B, 10C do not match the room temperature set values, the power consumption of the compressor 1 becomes excessive, and the liquid back phenomenon in which the refrigerant is sucked into the compressor 1 in the liquid state causes the compressor 1 There was a problem of being damaged.

[0011]

According to the present invention, in order to deal with the problem that the superheat degree of the suction portion of the compressor becomes excessive or excessive, the membership value determined by the superheat degree fuzzy calculation using the superheat degree as an input is used. Accordingly, each expansion valve operation amount determiner for mixing the operation amount by the superheat degree controller and each operation amount by each room temperature controller to determine the opening degree of each expansion valve is provided.

To solve the problem that the number of revolutions of the compressor is too small or too large for the load of each room, each room temperature deviation which is the difference between each room temperature and each room temperature set value and the rating of each room unit Determine the number of revolutions of the compressor for making the sum of the product values of the capability values equal to 0. Mix the amount of operation by the overall capacity controller and the amount of operation by the pressure controller to determine the number of revolutions of the compressor. The number of revolutions of the compressor is optimized while keeping the pressure within the proper range.

[0013]

According to the present invention, a multi-room air conditioner as described above provides a superheat controller which determines the operation amount of the opening degree of each expansion valve to make the superheat match the superheat set value. ,
The degree of superheat is kept within an appropriate range by each expansion valve operation amount determiner that mixes the amount of operation by the superheat degree controller and the amount of operation by each room temperature controller according to the degree of superheat.

Further, an overall capacity controller for determining the number of revolutions of the compressor for making the total value of the product values of the room temperature deviations and the rated capacity values of the indoor units equal to 0, and a pressure controller according to the pressure. Mix the manipulated variable and the manipulated variable by the total capacity controller,
By the compressor rotation speed determiner that determines the rotation speed of the compressor, while maintaining the pressure within the appropriate range, the rotation speed of the compressor is optimized, the output of each room temperature detector matches the room temperature set value, The power consumption of the compressor can be minimized, and further damage to the compressor due to liquid back of the refrigerant can be prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a multi-room air conditioner according to the present invention will be described below with reference to the drawings. FIG. 4 is a system configuration diagram of a multi-room air conditioner according to the present invention, which constitutes a heat pump cycle having the same operation as in FIG. 7, and further has a superheat detector 29 attached to the suction portion of the compressor 1. The same elements as in FIG. 7 are denoted by the same numbers.

The mode of operation of the multi-room air conditioner having such a configuration will be described below. At the time of changing each set room temperature value or the like, the opening degree of each indoor expansion valve 9A, 9B, 9C changes,
The degree of superheat becomes too small or too large, and each room temperature detector 1
Even when the outputs of 0A, 10B, and 10C match the room temperature set value, that is, at equilibrium, each room 11A, 11B, and 11
Depending on the relationship with the load of C, the degree of superheat becomes excessively small or excessive, and the degree of superheat is detected by the superheat detector 29.

FIG. 1 is a block diagram of a controller of an indoor expansion valve and a compressor of a multi-room air conditioner according to the present invention,
Each room temperature setting device 17A, 17B, 17C and each room temperature detector 1
Each of the room temperature controllers 15A, 15B, 15C which receives the output of each subtractor 19A, 19B, 19C which outputs the difference of each output from 0A, 10B, 10C, the superheat degree detector 29, and the target of the superheat degree The superheat degree controller 31 receives the output of the subtractor 19E that outputs the difference between each output from the superheat degree setter 30 that sets the value, and the superheat degree fuzzy operation that receives the output of the superheat degree detector 29 as an input. In accordance with the determined membership value, the operation amount of each room temperature controller 15A, 15B, 15C and the operation amount of the superheat degree controller 31 are mixed, and each indoor expansion valve 9 is mixed.
A, 9B, 9C, each indoor expansion valve operation amount determiner 32A, 32B, 32C for determining the opening degree, and each indoor unit 7A, 7B,
Each of the indoor unit rated capacity value setting devices 33A, 33B, 33C for setting each rated capacity value of 7C, each room temperature setting device 17A, 17B, 17C for setting the target value of each room temperature, and each room temperature detector 10A, 10B, Each indoor functional force multiplication which outputs each product of each output of each subtractor 19A, 19B, 19C which outputs the difference of each output with 10C and each output of each indoor unit rated capacity value setting device 33A, 33B, 33C. Vessels 34A, 34B, 34C
A total capacity adder 35 that outputs the sum of the outputs of the indoor functional power multipliers 34A, 34B, and 34C; a total capacity controller 36 that receives the output of the total capacity adder 35 as an input; A pressure controller 16 that receives an output of a subtractor 19D that outputs a difference between outputs of the pressure detector 14 and the pressure detector 14, and a membership value determined by a pressure fuzzy operation that receives an output of the pressure detector 14 as an input. A compressor operation amount determiner 37 for determining the number of revolutions of the compressor 1 by mixing the operation amount of the overall capacity controller 36 and the operation amount of the pressure controller 16 with the compressor operation amount determiner 37. The number of rotations of the compressor 1 is operated with the determined operation amount.

FIG. 2 is a flow chart showing the operation of the indoor expansion valve manipulated variable determiner according to the present invention.
9 is compared with the first superheat threshold (step 1).
01), if the output of the superheat detector 29 is larger than the first superheat threshold value, the superheat membership value is set to 0 (step 102), and the output of the superheat detector 29 is lower than the first superheat threshold value. If it is smaller, the output of the superheat detector 29 is compared with the second superheat threshold smaller than the first superheat threshold (step 103), and the output of the superheat detector 29 is lower than the second superheat threshold. If it is larger, a superheat degree membership value that monotonously and continuously changes in the range of 0 to 1 is set in accordance with the output of the superheat degree detector 29 (step 104),
If the output of the superheat detector 29 is smaller than the second superheat threshold, the output of the superheat detector 29 is compared with a third superheat threshold smaller than the second superheat threshold (step 10).
5) If the output of the superheat detector 29 is larger than the third superheat threshold, the superheat membership value is set to 1 (step 106), and the output of the superheat detector 29 is higher than the third superheat threshold. If it is smaller, the output of the superheat detector 29 is compared with a fourth superheat threshold smaller than the third superheat threshold (step 107), and the output of the superheat detector 29 is smaller than the fourth superheat threshold. If it is larger, a superheat degree membership value that changes monotonously and continuously in the range from 1 to 0 according to the output of the superheat degree detector 29 is set (step 108), and the output of the superheat degree detector 29 If it is smaller than the four superheat threshold, the superheat membership value is set to 0 (step 10).
2) After that, the product amount of the operation amount by each room temperature controller 15A, 15B, 15C and the superheat degree membership value, the operation amount by the superheat degree controller 32, and the value obtained by subtracting the superheat degree membership value from 1 Each indoor expansion valve 9A, 9B, as the sum of products
The opening of 9C is determined (step 109). That is, this is a superheat degree fuzzy calculator which receives the output of the superheat degree detector 29 as an input.

Further, depending on the operating state of the indoor units 7A, 7B, 7C (step 110), when the indoor units are stopped, the opening of each indoor expansion valve 9A, 9B, 9C is reduced by a small amount from the previous opening of the expansion valve. The degree of opening is set (step 111), then it is judged whether or not the operating states of the indoor units 7A, 7B, 7C and the compressor 1 have changed (step 112), and if there is a change, each indoor expansion valve 9A, The opening degree of 9B and 9C is set as the initial opening degree according to the change of the operating state (step 113), and is executed at fixed time intervals.

FIG. 3 is a flow chart showing the operation of the compressor manipulated variable determiner according to the present invention. The output of the pressure detector 14 is compared with the first pressure threshold value (step 201).
If the output of the pressure detector 14 is larger than the first pressure threshold, the pressure membership value is set to 0 (step 202),
If the output of the pressure detector 14 is smaller than the first pressure threshold, the output of the pressure detector 14 is compared with a second pressure threshold smaller than the first pressure threshold (step 203). If the output is larger than the second pressure threshold, a pressure membership value that changes monotonously and continuously from 0 to 1 according to the output of the pressure detector 14 is set (step 204), If the output of the pressure detector 14 is smaller than the second pressure threshold, the output of the pressure detector 14 is compared with a third pressure threshold smaller than the second pressure threshold (step 205). If it is greater than the third pressure threshold, the pressure membership value is set to 1 (step 206), and if the output of the pressure detector 14 is smaller than the third pressure threshold, the pressure membership value is calculated from the output of the pressure detector 14 and the third pressure threshold. Small fourth pressure Compares the value (Step 20
7) If the output of the pressure detector 14 is larger than the fourth pressure threshold value, set a pressure membership value that changes monotonously and continuously in the range of 1 to 0 according to the output of the pressure detector 14. (Step 208) If the output of the pressure detector 14 is smaller than the fourth pressure threshold, the pressure membership value is set to 0 (Step 202), and then the overall capacity controller 3
The rotation speed of the compressor 1 is determined as the sum of the product of the manipulated variable by 6 and the pressure membership value and the product of the manipulated variable by the pressure controller 16 and the value obtained by subtracting the pressure membership value from 1. Step 209) is executed at regular time intervals.

That is, this is a pressure fuzzy calculator which receives the output of the pressure detector 14.

The operation modes of the indoor expansion valve of the multi-room air conditioner and the controller of the compressor having such a configuration will be described below. At the time of cooling, each room temperature detector 10A, 10B, 1
Each room temperature detected at 0C is the room temperature setting device 17A, 17
If the output is higher than B and 17C, each room temperature controller 15
The indoor expansion valves 9A, 9B,
The valve opening of 9C is operated in the opening direction, and the overall capacity controller 3
6, the number of revolutions of the compressor 1 is operated in an increasing direction, and as a result, the amount of refrigerant flowing through each indoor heat exchanger 8A, 8B, 8C increases, the cooling capacity increases, each room temperature decreases, and each room temperature setting device It matches the output of 17A, 17B, 17C. This time,
The required cooling capacity depends on each indoor heat exchanger 8A, 8B, 8
C, that is, in the case of overload, the degree of superheat detected by the superheat degree detector 29 becomes small, and in the case of being smaller than the fourth superheat degree threshold, each indoor expansion valve operation amount determiner 32
In A, 32B, and 32C, the operation amounts of the superheat controller 31 are selected, and the indoor expansion valves 9A, 9B, and 9C are controlled so that the superheat detected by the superheat detector 29 matches the output of the superheat setter 30. By operating the opening degree in the closing direction, the cooling capacity of each of the indoor heat exchangers 8A, 8B, 8C can be suppressed within the appropriate upper limit capacity.

When each room temperature is lowered to some extent and the required cooling capacity is near the proper upper limit capacity of each indoor heat exchanger 8A, 8B, 8C, the superheat degree detected by the superheat detector 29 gradually increases. When it is larger than the fourth superheat threshold value and smaller than the third superheat threshold value, the operation amount by the superheat controller 31 and each room temperature controller 15A, 15B in each indoor expansion valve operation amount determiner 32A, 32B, 32C. , 15C are mixed with the manipulated variables for the indoor expansion valves 9
The indoor heat exchangers 8A, 8B and 8C are operated by operating the opening degrees of A, 9B and 9C.
Maintain C near the appropriate upper limit capacity.

When the room temperature is further lowered and the required cooling capacity is less than the appropriate upper limit capacity of each indoor heat exchanger 8A, 8B, 8C, the superheat degree detected by the superheat detector 29 becomes large, When it is larger than the third superheat threshold, the operation amount by each room temperature controller 15A, 15B, 15C is selected in each indoor expansion valve operation amount determiner 32A, 32B, 32C, and the opening degree of each indoor expansion valve 9A, 9B, 9C. Each room temperature is controlled by operating the room temperature setting devices 15A, 15B,
It matches the output of 15C.

When the room temperature is further lowered and the required cooling capacity is less than the proper lower limit capacity of the indoor heat exchangers 8A, 8B, 8C, the superheat degree detected by the superheat detector 29 is further increased. , If it is larger than the second superheat threshold, the operation amount by the superheat controller 31 in each indoor expansion valve operation amount determiner 32A, 32B, 32C and each room temperature controller 15A,
The operation amount mixed with the operation amount by 15B, 15C is selected and each indoor heat exchanger 8A, 8B, 8C is operated by operating the opening degree of each indoor expansion valve 9A, 9B, 9C. Maintain near the proper lower limit capacity of 8B and 8C.
As a result, each room temperature is set to each room temperature setting device 17A, 17B, 17
C, the rotation speed of the compressor 1 is operated in a decreasing direction by the overall capacity controller 36, the amount of refrigerant flowing through each of the indoor heat exchangers 8A, 8B, 8C decreases, and the cooling capacity decreases. Each room temperature rises, and each room temperature detector 10A, 10B,
The output of 10C is each room temperature setting unit 17A, 17B, 17C
Matches the output of.

Further, the pressure detected by the pressure detector 14 causes the pressure controller 16 in the compressor operation amount determiner 37.
And the operation amount by the overall capacity controller 36 are appropriately mixed, and the pressure is suppressed to a range between the first pressure threshold value and the fourth pressure threshold value.

Similarly, at the time of heating, an appropriate degree of superheat,
And room temperature control under pressure.

Furthermore, when the operation of any of the indoor units 7A, 7B, 7C is stopped, the indoor expansion valves 9A, 9B, 9C corresponding to the stopped indoor units are gradually closed to reduce the pressure and Stable operation can be realized without sudden changes in superheat.

Further, when the operating states of the indoor units 7A, 7B, 7C and the compressor 1 change, the opening degree of each indoor expansion valve 9A, 9B, 9C is set to the initial opening degree according to the operating state change. As a result, each indoor heat exchanger 8A, 8B, 8C
Can be made to be close to the proper capacity, and the influence of a change in the operating state on the room temperature of each room 11A, 11B, 11C can be reduced.

FIG. 5 is a system configuration diagram of a multi-room air conditioner according to another embodiment of the present invention, which constitutes a heat pump cycle having the same operation as that of FIG.
The intake saturation temperature detector 38 and the outdoor air temperature detector 39 for detecting the outdoor air temperature in which the outdoor unit 6 is installed are attached to the inhalation part of the device, and the same elements as those in FIG. 4 are denoted by the same numbers. .

The mode of operation of the multi-room air conditioner having such a configuration will be described below. Each indoor expansion valve 9A, 9B, 9
The intake saturation temperature changes according to the opening degree of C, the rotation speed of the compressor 1, the outside air temperature, and the like, and the intake saturation temperature is the intake saturation temperature detector 38.
Further, the outside air temperature is detected by the outside air temperature detector 39.

FIG. 6 is a block diagram of a controller of an indoor expansion valve and a compressor of a multi-room air conditioner according to another embodiment of the present invention, which constitutes a control block having the same operation as in FIG. Further, the output of the intake saturation temperature detector 38, the output of the outside air temperature detector 39, the room temperature detectors 10A, 10B, 10
A superheat target setter 40 that determines a superheat set value and a membership function of a superheat fuzzy operation according to each output of C
1 is attached, and the same elements as those in FIG. 1 are denoted by the same numbers.

The operation modes of the indoor expansion valve of the multi-room air conditioner and the controller of the compressor having such a configuration will be described below. During the cooling operation, the difference between the output of the suction saturation temperature detector 38 and the minimum output of the outputs of the room temperature detectors 10A, 10B, and 10C is set as the maximum superheat degree, and the superheat degree set value and the superheat degree fuzzy calculation are performed. Membership function, ie Figure 2
Each superheat threshold value in is determined by the superheat degree target setting device 40 so as to be equal to or less than the maximum superheat degree, and the difference between the output of the intake saturation temperature detector 38 and the output of the outside air temperature detector 39 during the heating operation is determined. The maximum superheat degree is set, and the superheat degree set value and the membership function of the superheat degree fuzzy calculation, that is, each superheat degree threshold value in FIG. 2, are determined by the superheat degree target setter 40 so as to be equal to or less than the maximum superheat degree.

As a result, a proper target value for superheat control is given, and it is possible to suppress an excessive rise in the discharge temperature of the compressor 1 that occurs when the target value for superheat control is excessive. Further, each room temperature detector 10A used for determining the maximum degree of superheat,
Instead of each output of 10B and 10C, each room temperature setting device 17
It is also possible to use the outputs of A, 17B, and 17C. Further, the target value of the superheat degree control is reduced and corrected when the number of revolutions of the compressor 1 is large, so that it is possible to reliably suppress the excessive rise of the discharge temperature of the compressor 1. Further, by determining the superheat degree set value and the membership function of the superheat degree fuzzy calculation according to the intake saturation temperature and the outside air temperature, each room temperature or each room temperature set value, an appropriate target value for the superheat degree control is given, Of the compressor, the discharge temperature of the compressor can be prevented from rising excessively when the target value of the superheat control is excessive.By correcting the target value of the superheat control according to the number of revolutions of the compressor, It is possible to more reliably prevent the discharge temperature from rising excessively.

[0035]

As described above, in the multi-room air conditioner according to the present invention, the operation amount by the superheat degree controller and each operation amount by each room temperature controller are mixed according to the superheat degree, and thereby, the proper operation is always performed. Room temperature control based on a high degree of superheat and pressure can be realized, power consumption of the compressor can be minimized, and damage to the compressor due to liquid back of the refrigerant can be prevented.

When any one of the indoor units stops operating, the indoor expansion valve corresponding to the stopped indoor unit is gradually closed, so that the pressure and the degree of superheat do not suddenly change. When the operating state of the indoor unit and compressor changes, the opening of each indoor expansion valve is set to the initial opening according to the operating state change, so that the capacity of each indoor heat exchanger is close to the appropriate capacity. Therefore, it is possible to reduce the influence of the change in the operating state on the room temperature of each room, and to realize stable operation.

[Brief description of drawings]

FIG. 1 is a control block configuration diagram of an indoor expansion valve and a compressor of a multi-room air conditioner according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of an indoor expansion valve operation amount determiner in the air conditioner.

FIG. 3 is a flowchart showing the operation of a compressor manipulated variable determiner in the air conditioner.

FIG. 4 is a system configuration diagram of the air conditioner.

FIG. 5 is a system configuration diagram of a multi-room air conditioner according to another embodiment of the present invention.

FIG. 6 is a control block configuration diagram of an indoor expansion valve and a compressor of the multi-room air conditioner.

FIG. 7 is a system configuration diagram of a conventional multi-room air conditioner.

FIG. 8 is a control block configuration diagram of an indoor expansion valve and a compressor of the multi-room air conditioner.

[Explanation of symbols]

1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Receiver 5 Accumulator 6 Outdoor unit 7A, 7B, 7C Indoor unit 8A, 8B, 8C Indoor heat exchanger 9A, 9B, 9C Indoor expansion valve 10A, 10B, 10C Room temperature detector 11A, 11B, 11C Room 12 Gas side pipeline 13 Liquid side pipeline 14 Pressure detector 15A, 15B, 15C Room temperature controller 16 Pressure controller 17A, 17B, 17C Room temperature setter 18 Pressure setter 19A, 19B, 19C, 19D, 19E Subtractor 20A, 20B, 20C, 20D, 20E Integrator 21A, 21B, 21C, 21D, 21E Differentiator 22A, 22B, 22C, 22D, 22E Proportional coefficient setter 23A, 23B, 23C, 23D, 23E Integration Coefficient setting device 24A, 24B, 24C, 24D, 24E Differential coefficient setting device 25A, 25B, 5C, 25D, 25E 1st multiplier 26A, 26B, 26C, 26D, 26E 2nd multiplier 27A, 27B, 27C, 27D, 27E 3rd multiplier 28A, 28B, 28C, 28D, 28E Adder 29 Overheat detection Unit 30 Superheat degree setter 31 Superheat degree controller 32A, 32B, 32C Indoor expansion valve operation amount determiner 33A, 33B, 33C Indoor unit rated capacity value setter 34A, 34B, 34C Indoor functional force multiplier 35 Overall capacity adder 36 Overall Capacity Controller 37 Compressor Operating Quantity Determiner 38 Intake Saturation Temperature Detector 39 Outside Air Temperature Detector 40 Superheat Target Setter

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yuji Yoshida 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kanji Haneda, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. In the company

Claims (6)

(57) [Claims] 1. An outdoor unit comprising a compressor, an outdoor heat exchanger, a four-way valve, etc., an indoor heat exchanger, and a plurality of indoor units equipped with an expansion valve etc. are connected in parallel, Each room temperature detector that detects each room temperature in which each indoor unit is installed, a superheat detector that detects the degree of superheat in the compressor suction part, and each of the above-mentioned each room temperature to match each room temperature set value Each room temperature controller that determines the manipulated variable of the opening degree of the expansion valve, and a superheat degree controller that determines the manipulated variable of the opening degree of each of the expansion valves to match the superheat degree with a superheat degree set value, and According to the membership value determined by the superheat degree fuzzy calculation with the superheat degree as an input, the operation amount by the superheat degree controller and each operation amount by the room temperature controllers are mixed to determine the opening degree of each expansion valve. Expansion valve manipulated variable determiner and each room temperature that is the difference between each room temperature and each room temperature set value A total capacity controller that determines the number of revolutions of the compressor for making the sum of the product of the difference and the rated capacity of each indoor unit equal to 0, and a pressure detector that detects the pressure of the indoor heat exchanger. And a pressure controller for determining the manipulated variable of the rotational speed of the compressor for causing the pressure to match a set value, and the pressure according to the membership value determined by a pressure fuzzy operation using the pressure as an input. A multi-room air conditioner comprising a compressor rotation speed determiner for determining the rotation speed of the compressor by mixing the operation quantity by a controller and the operation quantity by the overall capacity controller. 2. The expansion valve operation amount determiner includes a stop-time expansion valve operation function for gradually operating a degree of opening of an expansion valve of an indoor unit that is not in operation. 1. The multi-room air conditioner described in 1. 3. The expansion valve manipulated variable determiner has a function to determine the opening degree of the expansion valve when the operating state changes, which determines the opening degree of each expansion valve according to the change of the operating or stopped state of each indoor unit and compressor. The multi-room air conditioner according to claim 1, characterized in that it comprises. 4. A suction saturation temperature detector for detecting a saturation temperature in a compressor suction portion, an outside air temperature detector for detecting an outside air temperature in which an outdoor unit is installed, the suction saturation temperature, each room temperature and the outside air temperature. 2. The multi-room air conditioner according to claim 1, further comprising a superheat target setter that determines a superheat set value and a membership function of the superheat fuzzy calculation according to the above. 5. A superheat degree target setting device for determining a superheat degree set value and a membership function of a superheat degree fuzzy operation according to the intake saturation temperature, each room temperature set value, and the outside air temperature. Item 4. The multi-room air conditioner according to Item 4. 6. The superheat target setting device includes a superheat correction function for correcting a superheat set value and a membership function of the superheat fuzzy calculation according to the number of revolutions of the compressor. Item 4. The multi-room air conditioner according to Item 4.