KR20030085235A - Multi-type air conditioner - Google Patents

Abstract

PURPOSE: A multi type air conditioner is provided to control opening degree of an electromotive expansion valve so that discharge temperature of a compressor reaches optimum discharge temperature. CONSTITUTION: An outdoor unit(A) includes a compressor(10); a four-way valve(11); an outdoor heat exchanger(12); electromotive expansion valves(13,14) corresponding with indoor units(B1,B2); an accumulator(15) and a compressor discharge temperature sensor(16). The indoor units include indoor heat exchangers(18); indoor temperature sensors(19); indoor heat exchanger inlet temperature sensors(20); and indoor heat exchanger midway temperature sensors(21). An outdoor controller determines opening degrees of the electromotive expansion valves considering current fluctuation of discharge temperature of the compressor, fluctuation of indoor temperature and outdoor temperature of the indoor heat exchangers, and fluctuation of displacement of the compressor. The displacement of the compressor is operational frequency of the compressor, i.e., output frequency of an inverter circuit.

Description

Tea room air conditioner {MULTI-TYPE AIR CONDITIONER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner, and more particularly, to a multi-room air conditioner for optimizing a cycle by controlling an opening degree of an electric expansion valve in a multi-room air conditioner having one outdoor unit and a plurality of indoor units. .

In general, a multi-room air conditioner includes one outdoor unit and a plurality of indoor units. The outdoor unit includes a compressor, a four-way valve, an outdoor heat exchanger, and an electric expansion valve. Each indoor unit has an indoor heat exchanger. The compressor, four-way valve, outdoor heat exchanger, electric expansion valve and each indoor heat exchanger are connected to form a cycle. An electric expansion valve is provided in the refrigerant pipe which connects between an outdoor heat exchanger and each indoor heat exchanger.

In the air conditioner in the multi-room air conditioner, the high temperature and high pressure refrigerant discharged from the compressor passes through the 4-way valve and the outdoor heat exchanger, and then passes through each electric expansion valve that controls the pressure and the amount of refrigerant before entering the indoor heat exchanger. . The motor expansion valve maintains the initial opening for a certain time after the compressor is started. At this time, the indoor superheat control (control of the difference between the inlet and outlet temperatures of the indoor heat exchanger to 0 ± 1 ° C) is started. The refrigerant passing through the indoor heat exchanger is recycled to the compressor.

Meanwhile, in the heating mode, the high temperature and high pressure refrigerant discharged from the compressor passes through the 4-way valve and the indoor heat exchanger, and then passes through the electric expansion valve before entering the outdoor heat exchanger. The motor expansion valve maintains the initial opening for a predetermined time after the compressor is started. At this time, the outdoor superheat control (controlling the difference between the suction temperature of the compressor and the inlet temperature of the outdoor heat exchanger at 1 ° C) is started. The refrigerant passing through the outdoor heat exchanger is recycled to the compressor.

In the multi-room air conditioner according to the prior art, the opening degree of the electric expansion valve is controlled so that the difference between the inlet temperature and the outlet temperature of the indoor heat exchanger becomes 0 ± 1 ° C during cooling operation. In this case, the inlet temperature / outlet temperature of the indoor heat exchanger is 10/10, 11/11, 12 when the compressor's capacity varies from the minimum to the maximum. The outlet temperature of the indoor heat exchanger can rise because it can be / 12, 13/13 ° C. Accordingly, if the discharge temperature of the compressor gradually rises, overload of the compressor may occur, so that the optimum performance of the air conditioner may not be achieved, and the difference between the inlet temperature and the outlet temperature of the indoor heat exchanger is within the range of 0 ± 1 ° C. Since the temperature control is relatively small, it is difficult to finely control the opening degree of the electric expansion valve.

In addition, the opening degree of the electric expansion valve is controlled so that the difference between the suction temperature of the compressor and the inlet temperature of the outdoor heat exchanger is 1 ° C. during the heating operation. When the capacity variable compressor is applied, the compressor has a variable capacity from minimum to maximum. In case of controlling only depending on the difference between the suction temperature and the inlet temperature of the outdoor heat exchanger, the suction temperature / outdoor heat exchanger inlet temperature can be 1/0, 2/1, 3/2, 4/3 ℃. In addition to the lack of optimum performance, the temperature difference is relatively small because the difference between the suction temperature of the compressor and the inlet temperature of the indoor heat exchanger is controlled within the range of 1 ° C. There is difficulty.

On the other hand, in a multi-room operation in which more than one room is air-cooled at the same time, if the air temperature of each indoor unit is different from each other, the refrigerant tends to flow to the indoor unit having a low indoor temperature, that is, a low load indoor heat exchanger, during the time of controlling the electric expansion valve to the initial opening. As a result, excessive refrigerant flows into the indoor indoor chamber of low indoor temperature, so that the outlet temperature of the low load indoor heat exchanger is lowered, while relatively low refrigerant flows into the indoor indoor chamber of high load, that is, the high load indoor heat exchanger. As the refrigerant is insufficient, the outlet temperature of the indoor heat exchanger rises above the inlet temperature. Accordingly, when the time for controlling the electric expansion valve to the initial opening is over, the opening degree of the electric expansion valve corresponding to the high load indoor heat exchanger is close to full opening for the purpose of equalizing the inlet temperature and the outlet temperature of the indoor heat exchanger. As the opening degree of the electric expansion valve corresponding to the indoor heat exchanger of low load becomes narrow, the refrigerant circulated to the compressor excessively flows, which not only adversely affects the reliability of the compressor but also lowers the cooling performance and efficiency of the indoor unit. .

In the multi-room operation in which two or more rooms simultaneously heat the refrigerant, the refrigerant is excessively concentrated in one indoor unit due to the length of the refrigerant pipe or other factors during the initial opening time of the electric expansion valve. do. This causes unbalance of the refrigerant in the indoor period. However, conventionally, by performing the control of the electric expansion valve based on the suction temperature and the inlet temperature of the outdoor heat exchanger, there is a problem that the heating performance and efficiency of the indoor unit is lowered because the unbalance of the refrigerant cannot be solved.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electric expansion valve in which the discharge temperature of the compressor reaches a target discharge temperature that satisfactorily satisfies the suction superheat of the compressor according to the required capability of each indoor unit. To provide a multi-room air conditioner for controlling the opening degree.

Another object of the present invention is to provide a multi-room air conditioner that can finely control the opening degree of the electric expansion valve by using the difference between the discharge temperature and the target discharge temperature of the compressor.

Another object of the present invention is to reduce the inlet temperature of a high load indoor heat exchanger by using the average temperature averaged inlet temperature of each indoor heat exchanger in a multi-room operation in which two or more rooms are cooled or heated. The inlet temperature is raised to provide a multi-room air conditioner that can actively respond to the load of each indoor unit.

1 is a configuration diagram illustrating a refrigerant cycle of a multi-room air conditioner according to the present invention.

2 is a control block diagram of a multi-room air conditioner according to the present invention.

3 is a control flowchart illustrating an operation of controlling the opening degree of the electric expansion valve based on the discharge temperature of the compressor in the multi-room air conditioner according to the present invention.

Figure 4 is a view showing an embodiment for the constants determined according to the number of operating units of the indoor unit during the heating and cooling according to the present invention.

5 is a control flowchart illustrating an operation of controlling the opening degree of the electric expansion valve when the indoor temperature of each indoor unit is different from each other in a multi-room operation in which two or more indoor units simultaneously perform cooling operations.

6 is an embodiment of the present invention to control the opening degree of the electric expansion valve based on the average temperature averaged the discharge temperature of the compressor and the inlet temperature of the indoor heat exchanger in the multi-room operation in which two or more indoor units perform the cooling operation at the same time This is a control flow chart for how to do it.

7 is a view for controlling the opening degree of the electric expansion valve based on an average temperature obtained by averaging the discharge temperature of the compressor and the intermediate temperature of the indoor heat exchanger in a multi-room operation in which two or more indoor units are heated. This is the control flow chart.

* Description of the code for the main functions of the drawings

10 compressor 11 4-way valve

12: outdoor heat exchanger 13, 14: electric expansion valve

15 Accumulator 16 Compressor Discharge Temperature Sensor

17: outdoor temperature sensor 18: indoor heat exchanger

19: room temperature sensor 20: indoor heat exchanger inlet temperature sensor

21: middle temperature sensor of indoor heat exchanger 30: indoor controller

40: outdoor controller 60: inverter circuit

An object of the present invention as described above is a plurality of indoor units connected to one outdoor unit, the outdoor unit has a compressor and an outdoor heat exchanger, each indoor unit has an indoor heat exchanger, a refrigerant pipe connected between the outdoor heat exchanger and each indoor heat exchanger A multi-room air conditioner provided with an electric expansion valve for adjusting a flow rate of a refrigerant in the air conditioner, comprising: compressor discharge temperature detection means for detecting a discharge temperature of the compressor; And a target discharge temperature of the compressor for optimally satisfying the suction superheat degree of the compressor according to the required capability of the indoor unit, and based on the difference between the discharge temperature detected by the compressor discharge temperature detection means and the target discharge temperature. It is achieved by control means for controlling the opening degree of the electric expansion valve.

An object of the present invention as described above is a plurality of indoor units connected to one outdoor unit, the outdoor unit has a compressor and an outdoor heat exchanger, each indoor unit has an indoor heat exchanger, a refrigerant pipe connected between the outdoor heat exchanger and each indoor heat exchanger A multi-room air conditioner provided with an electric expansion valve for controlling a flow rate of a refrigerant in the air conditioner, the air conditioner comprising: temperature detecting means for detecting a temperature of an inlet region and an intermediate region of the indoor heat exchanger; And a difference between the average temperature obtained by averaging the inlet temperature of the indoor heat exchanger detected by the temperature detecting means and the inlet temperature of the corresponding indoor heat exchanger corresponding to the electric expansion valve to be controlled, and the intermediate temperature and the inlet of the indoor heat exchanger. It achieves by control means which controls the opening degree of the electric expansion valve of a control object based on a difference of temperature.

An object of the present invention as described above is a plurality of indoor units connected to one outdoor unit, the outdoor unit has a compressor and an outdoor heat exchanger, each indoor unit has an indoor heat exchanger, a refrigerant pipe connected between the outdoor heat exchanger and each indoor heat exchanger A multi-room air conditioner provided with an electric expansion valve for adjusting a flow rate of a refrigerant in the air conditioner, comprising: compressor discharge temperature detection means for detecting a discharge temperature of the compressor; Temperature detecting means for detecting temperatures of an inlet region and an intermediate region of the indoor heat exchanger, respectively; And setting a target discharge temperature of a compressor that satisfies the suction superheat degree of the compressor according to the required capability of each indoor unit according to the operation mode, and in the cooling mode, the discharge temperature detected by the compressor discharge temperature detection means. On the basis of a difference between a target discharge temperature determined to correspond to the cooling mode, a difference between an intermediate temperature and an inlet temperature of the indoor heat exchanger detected by the temperature detecting means, and an average temperature obtained by averaging the inlet temperature of the indoor heat exchanger; The opening degree of the electric expansion valve is controlled, and in the heating mode, the difference between the discharge temperature detected by the compressor discharge temperature detection means and the target discharge temperature determined to correspond to the heating mode, and the indoor heat exchanger detected by the temperature detection means. By control means for controlling the opening degree of the corresponding electric expansion valve based on the average temperature averaged It is achieved.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of an air conditioner according to the present invention.

Referring to FIG. 1, reference numeral A denotes an outdoor unit, and B1 and B2 denote indoor units installed in different indoor spaces. The outdoor unit A includes a compressor 10, a four-way valve 11, an outdoor heat exchanger 12, an electric expansion valve 13 and 14 corresponding to each indoor unit, an accumulator 15, and a compressor discharge temperature sensor 16. ). Each indoor unit B1 and B2 includes an indoor heat exchanger 18, an indoor temperature sensor 19, an indoor heat exchanger inlet temperature sensor 20, and an indoor heat exchanger intermediate temperature sensor 21.

The discharge side of the compressor 10 is connected to one side of the outdoor heat exchanger 12 through the four-way valve (11). The other side of the outdoor heat exchanger 12 is connected to the refrigerant pipe (W). The refrigerant pipe W is branched into the refrigerant pipe W1 and the refrigerant pipe W2, and the branched cold pipes W1 and W2 are connected to the indoor heat exchanger 18 of each indoor unit B1 and B2. The refrigerant pipes W1 and W2 are provided with electric expansion valves 13 and 14 corresponding to the indoor unit. The flow rate of the refrigerant passing through the indoor heat exchanger 18 of each of the indoor units B1 and B2 is adjusted in accordance with the opening degree of the electric expansion valves 13 and 14.

The outlet of the indoor heat exchanger 18 of each indoor unit B1 (B2) is connected to the refrigerant pipes G1 and G2, respectively, and the refrigerant pipe G to which the refrigerant pipe G1 and the refrigerant pipe G2 join. Is connected to the suction side of the compressor 10 via a four-way valve 11 and an accumulator 15.

The compressor discharge temperature sensor 16 is provided in the refrigerant pipe connecting the outlet of the compressor 10 and the four-way valve 11 to detect the temperature of the refrigerant discharged from the compressor 10.

The indoor heat exchanger inlet temperature sensor 20 is provided in the inlet side refrigerant pipe of the indoor heat exchanger 18 to detect the inlet temperature of the indoor heat exchanger 18.

The indoor heat exchanger intermediate temperature sensor 21 is provided in the middle region of the indoor heat exchanger 18 to detect the intermediate temperature of the indoor heat exchanger 18.

The outdoor heat exchanger 12 of the outdoor unit A is provided with an outdoor temperature sensor 17 for detecting the outdoor temperature, and the indoor heat exchanger 18 of each indoor unit B1 or B2 is configured to detect the indoor air temperature. An indoor temperature sensor 19 is provided.

2 is a control block diagram of a multi-room air conditioner according to the present invention.

In Fig. 2, reference numeral 50 denotes a commercial AC power source connected to the outdoor controller 40 of the outdoor unit A.

The outdoor controller 40 includes a microcomputer and its peripheral circuits and controls the overall operation of the outdoor unit. The outdoor controller 40 includes electric expansion valves 13 and 14, four-way valves 11, an outdoor fan motor 41, a compressor frequency detector 42, a compressor discharge temperature sensor 16, and an outdoor temperature sensor 17. The inverter circuit 60 is connected.

The inverter circuit 60 rectifies the voltage supplied from the commercial AC power supply 50, converts the rectified voltage according to a control command from the outdoor controller 40 into a voltage level of a set frequency, and then the compressor motor 61. To feed. The output of the interleaver circuit 60 is supplied to the compressor motor 61 as compressor drive power. The compressor frequency detector 42 receives the output of the inverter circuit 60 and detects the frequency of the compressor in operation and inputs it to the outdoor controller 40.

Each indoor unit B1 and B2 includes an indoor controller 30. The indoor controller 30 includes a microcomputer and its peripheral circuits and controls the overall operation of the indoor unit.

The indoor controller 30 of each indoor unit B1 (B2) includes an indoor temperature sensor 19, an indoor heat exchanger inlet temperature sensor 20, an indoor heat exchanger intermediate temperature sensor 21, and an indoor fan motor 31, respectively. The indoor controller 30 is connected to a remote controller 70 for remotely operating the indoor unit. In addition, the indoor controller 30 is connected to the outdoor controller 40 through the communication line 80 to communicate with the outdoor unit (A).

The outdoor controller 40 has a refrigerant discharged from the compressor 10 according to a cooling mode operation command from the indoor unit controller 30 of each indoor unit B1 or B2, and the 4-way valve 11 and the outdoor heat exchanger 12. The electric expansion valves 13 and 14, the indoor heat exchanger 18, and the four-way valve 11 are circulated. Thus, the cooling operation is performed.

In addition, the outdoor controller 40 is the refrigerant discharged from the compressor 10 according to the heating mode operation command from the indoor unit controller 30 of each indoor unit (B1) (B2) is a four-way valve 11, the indoor heat exchanger ( 18), the electric expansion valve (13, 14), the outdoor heat exchanger (12), the four-way valve (11) to be circulated. Accordingly, the heating operation is performed.

The indoor controller 30 of each indoor unit B1 (B2) displays the operation mode command and setting indoor temperature input from the remote controller 70, and the indoor temperature detected by the indoor temperature sensor 19. To send.

The outdoor controller 40 switches the four-way valve 11 according to the operation mode, and at the same time, based on the control signals from the indoor controller 30 and the detection results of the various sensors described above, the electric expansion valves 13 and 14 are operated. And the rotation speed of the outdoor fan motor 41 and the compressor motor 61. At this time, the outdoor controller 40 controls the capacity of the compressor 10 according to the sum of the required capabilities required by each indoor controller 30, the compressor being applied to the compressor motor through a variable speed compressor, for example, inverter control. In the case of controlling the rotation speed of the motor by changing the frequency of the current, the compressor capacity is controlled by changing the output frequency of the inverter circuit 60. Here, the output frequency of the inverter circuit corresponds to the operating frequency of the compressor.

The outdoor controller 40 controls the opening degree of the electric expansion valve 13 and 14 corresponding to each indoor unit B1 (B2), and adjusts the air-conditioning capability of each indoor unit B1 (B2). At this time, the opening degree of the electric expansion valves 13 and 14 controlled by the outdoor controller 40 is controlled in the range of 481 steps (0 to 480), for example. Here, step 0 is a fully closed state of the electric expansion valve and step 480 is a fully open state.

On the other hand, in order to improve the reliability of the compressor, the outdoor controller 40 controls the opening degree of the electric expansion valve (13, 14) based on the discharge temperature of the compressor 10, for this purpose the upper limit of the indoor temperature and outdoor temperature and After setting the lower limit and the compressor discharge temperature (standard temperature) in the normal state and the target discharge temperature of the compressor that can achieve the optimum performance while satisfying the suction superheat of the compressor under each set condition, the outdoor controller (40) In the memory of

When the target discharge temperature of the compressor is determined, the outdoor controller 40 changes the discharge temperature of the current compressor 10 according to the target discharge temperature, the change of the inlet and outlet temperatures of the indoor heat exchanger 18, and the compressor capacity (compressor). The opening degree of the electric expansion valves 13 and 14 is determined in consideration of the change in the output frequency of the inverter circuit as the operating frequency. In addition, in the case of a multi-room operation in which two or more rooms are simultaneously cooled and operated, the outdoor controller 40 may further include an electric expansion valve (13) by considering the average temperature of the indoor heat exchanger inlet temperature of the indoor unit in operation and the change of the indoor heat exchanger inlet temperature. And (14), and in the case of a multi-room operation in which two or more rooms are heated at the same time, the motor expansion is further considered in consideration of the change in the average temperature of the indoor heat exchanger of the indoor unit in operation and the change of the intermediate temperature of the indoor heat exchanger. The opening degree of the valves 13 and 14 is determined.

Hereinafter, an operation for controlling the opening degree of the electric expansion valve based on the discharge temperature of the compressor will be described.

Referring to FIG. 3, the outdoor controller 40 determines whether the operation mode is the cooling mode according to the operation mode command transmitted from the indoor controller 30 (S100).

If the determination result is the cooling mode, the outdoor controller 40 is set to the cooling mode, and the initial control of the electric expansion valves 13 and 14 in the cooling mode is started (S101). Accordingly, the motor expansion valves 13 and 14 move in the set initial opening degree.

The outdoor controller 40 performs initial control for a preset initial control time, determines whether the initial control time is ended (S102), and as a result of the determination, calculates a target discharge temperature of the compressor (S103). ). At this time, the outdoor controller 40 calculates the target discharge temperature of the compressor using the capacity (operation frequency) of the compressor, the outdoor temperature detected by the outdoor temperature sensor 21, and the indoor temperature transmitted from each indoor controller 30. .

The target discharge temperature of the compressor that satisfactorily satisfies the suction superheat degree of the compressor according to the required capacity of each indoor unit operating in the cooling mode is calculated according to the following equation (1).

T_d_c = (C1 × Cf) + (To-35) × C2 + (27-Ti) × C3 + C4 ----- (Equation 1)

Where Cf is the compressor's capacity (operating frequency) according to the required capacity from the indoor unit in operation, To is the outdoor temperature, Ti is the average indoor temperature of the indoor unit in operation, and 35 and 27 are the upper limit values of the outdoor and indoor temperatures, respectively. As an example, C1, C2, C3 and C4 are constants determined according to the number of operating units of the indoor unit in the cooling mode as shown in FIG.

When the target discharge temperature of the compressor is calculated, the outdoor controller 40 calculates a difference between the discharge temperature of the compressor and the target discharge temperature detected by the compressor discharge temperature sensor 16 (S104).

The outdoor controller 40 calculates a difference between the inlet temperature and the intermediate temperature of the indoor heat exchanger detected by the inlet temperature sensor 20 and the intermediate temperature sensor 21 of the indoor heat exchanger (S105).

The outdoor controller 40 controls the opening degree of the electric expansion valves 13 and 14 by using the difference between the discharge temperature of the compressor and the target discharge temperature, and the difference between the inlet temperature and the intermediate temperature of the indoor heat exchanger (S106). At this time, when the calculated temperature difference is positive, the control is performed to widen the openings of the electric expansion valves 13 and 14, and when the temperature difference is negative, the control to narrow the openings of the electric expansion valves 13 and 14 is performed. Here, the opening degree (output step) of the electric expansion valve is, for example, in the range of 481 steps (0 to 480), and the output step of the electric expansion valve is determined by each temperature difference. The output step 0 is a state in which the opening degree of the electric expansion valve is completely closed, and the output step 480 is a state in which the opening degree of the electric expansion valve is completely opened.

Subsequently, the outdoor controller 40 determines whether the compressor operation stop command is input from the indoor controller 30 (S107). If the operation stop command is not inputted as a result of the determination, the process returns to step 103, and when the operation stop command is inputted, the operation of controlling the opening degree of the electric expansion valves 13 and 14 ends (S108).

On the other hand, if the operation mode command transmitted from the indoor controller 30 is a heating operation command, the outdoor controller 40 is set to the heating mode, and the electric expansion valves 13 and 14 in the heating mode are determined. Initial control is started (S110). Accordingly, the motor expansion valves 13 and 14 move in the set initial opening degree.

The outdoor controller 40 performs initial control for a preset initial control time, determines whether the initial control time is ended (S111), and sets the target discharge temperature of the compressor when the initial control time ends as a result of the determination (S112). ). At this time, the outdoor controller 40 calculates the target discharge temperature of the compressor using the capacity (operation frequency) of the compressor, the outdoor temperature detected by the outdoor temperature sensor 21, and the indoor temperature transmitted from the indoor controller 30.

The target discharge temperature of the compressor that satisfactorily satisfies the suction superheat degree of the compressor according to the required capacity of each indoor unit operating in the heating mode is calculated according to the following expression (3).

T_d_c = (C1 × Cf) + (To-7) × C2 + (Ti-20) × C3 + C4 ----- (Equation 2)

Where Cf is the compressor's capacity (operating frequency) according to the required capacity from the indoor unit in operation, To is the outdoor temperature, Ti is the average indoor temperature of the indoor unit in operation, and 7 and 20 are the lower limit values of the outdoor and indoor temperatures, respectively. As an example, C1, C2, C3, and C4 are constants determined according to the number of operating units of the indoor unit in the heating mode as shown in FIG.

When the target discharge temperature of the compressor is determined, the outdoor controller 40 calculates a difference between the discharge temperature of the compressor and the target discharge temperature detected by the compressor discharge temperature sensor 16 (S113).

The outdoor controller 40 calculates a difference between the inlet temperature and the intermediate temperature of the indoor heat exchanger detected by the inlet temperature sensor 20 and the intermediate temperature sensor 21 of the indoor heat exchanger (S114).

The outdoor controller 40 controls the opening degree of the electric expansion valves 13 and 14 by using the calculated difference between the discharge temperature of the compressor and the target discharge temperature, and the difference between the inlet temperature and the intermediate temperature of the indoor heat exchanger (S115). At this time, when the calculated temperature difference is positive, the control is performed to widen the openings of the electric expansion valves 13 and 14, and when the temperature difference is negative, the control to narrow the openings of the electric expansion valves 13 and 14 is performed.

Subsequently, the outdoor controller 40 determines whether the compressor operation stop command is input from the indoor controller 30 (S116). If the operation stop command is not input as a result of the determination, the process returns to step 112, and when the operation stop command is input, the operation of controlling the opening degree of the electric expansion valves 13 and 14 ends (S108).

Hereinafter, as another embodiment of the present invention, a method of controlling the opening degree of the electric expansion valve when the indoor temperature of each indoor unit is different from each other in a multi-room operation in which two or more indoor units perform the cooling operation simultaneously.

FIG. 5 is a control flow chart of a method of controlling the opening degree of the electric expansion valve in the cooling mode operation. The electric expansion valve corresponding to the indoor unit B1 when two chambers are operated for the indoor unit B1 and the indoor unit B2. This is an example of controlling the opening degree of (13).

Referring to FIG. 5, the outdoor controller 40 determines whether the cooling mode is in the cooling mode (S200). If the determination results in the cooling mode, initial control of the electric expansion valve 13 is initiated. Move to the set initial opening. The outdoor controller 40 performs initial control during the initial control time (S201). It is determined whether the initial control time has ended (S202), and as a result of the determination, by the inlet temperature sensor of the indoor heat exchanger of the indoor unit B1 and the inlet temperature sensor of the indoor heat exchanger of the indoor unit B2, respectively. The average temperature is calculated by averaging the detected inlet temperatures (S203).

When the average temperature is calculated, the outdoor controller 40 calculates a difference between the calculated average temperature and the inlet temperature detected by the inlet temperature sensor of the indoor heat exchanger of the indoor unit B1 (S204).

In addition, the outdoor controller 40 calculates a difference between the intermediate temperature detected by the intermediate temperature sensor of the indoor heat exchanger of the indoor unit B1 and the inlet temperature detected by the indoor heat exchanger inlet temperature sensor of the indoor unit B1 (S205). ). At this time, the reason for using the intermediate temperature of the indoor heat exchanger of the indoor unit (B1) is because the refrigerant discharged from the outlet of the indoor heat exchanger of the indoor unit (B1) is a gas state, so the temperature change is severe and it is not easy to control properly. In this regard, the intermediate temperature detected in the middle region of the indoor heat exchanger, in which the temperature change is relatively stable, is used.

The outdoor controller 40 uses the difference between the calculated average temperature and the inlet temperature of the indoor heat exchanger of the indoor unit B1 and the difference between the intermediate temperature and the inlet temperature of the indoor heat exchanger of the indoor unit B1 to determine the opening degree of the electric expansion valve. When the temperature difference is all positive, the control is performed to widen the opening degree of the electric expansion valve 13, and when the temperature difference is negative, the control to narrow the opening degree of the electric expansion valve 13 is performed (S206). On the other hand, the method of controlling the opening degree of the electric expansion valve 14 of the indoor unit B2 is the same as the method of controlling the opening degree of the electric expansion valve 13 of the indoor unit B1.

Therefore, even when the indoor temperature of each indoor period is different, the opening degree of the electric expansion valve corresponding to the indoor unit of high load is not excessively opened and maintains the proper opening degree.

Hereinafter, an operation of controlling the opening degree of the electric expansion valve according to another embodiment of the present invention will be described.

FIG. 6 is a control flowchart illustrating a method of controlling the opening degree of the electric expansion valve based on an average temperature obtained by averaging the discharge temperature of the compressor and the inlet temperature of the indoor heat exchanger during the cooling operation, and showing the indoor unit B1 and the indoor unit B2. The operation of controlling the opening degree of the electric expansion valve 13 of the indoor unit B1 in the case of two-room operation as an object is explained.

With reference to FIG. 6, the output step of the electric expansion valve 13 of the indoor unit B1 at the time of cooling is computed based on the following (formula 3).

Output Step = (Deviation 1 × E + d Deviation 1 × D) × Weight 1 + (Deviation 2 × C) × Weight 2 + (Deviation 3 × Weight 3) + (Deviation 4 × Weight 4) ----- ( Equation 3

Where deviation 1 = discharge temperature of the compressor (T_dis)-target discharge temperature (T_d_c),

d deviation 1 = current deviation 1-previous deviation 1,

Deviation 2 = average inlet temperature of the indoor heat exchanger [(Teva_in, a + Teva_in, b) / 2]-inlet temperature of the indoor heat exchanger of the indoor unit B1 (Teva_in, a),

Deviation3 = capacity of current compressor (Cf)-capacity of previous compressor (Cf),

Deviation 4 = middle temperature (Teva_mid, a) of indoor heat exchanger of indoor unit (B1)-inlet temperature (Teva_in, a) of indoor heat exchanger of indoor unit (B1),

E, D, C, weight 1, weight 2, weight 3, weight 4 is a constant determined according to the number of operating units of the indoor unit during cooling as shown in FIG.

First, the outdoor controller 40 calculates the deviation 1 from the discharge temperature of the compressor 10 detected by the discharge temperature sensor 16 of the compressor and the target discharge temperature during cooling calculated in Equation (1). In addition, when the calculation for the deviation 1 is completed, the outdoor controller 40 calculates the d deviation 1 using the previous deviation and the current deviation for the deviation 1 (S300).

The outdoor controller 40 calculates an average temperature of the inlet temperatures detected from the inlet temperature sensor of the indoor heat exchanger of the indoor unit B1 and the inlet temperature sensor of the indoor heat exchanger of the indoor unit B2, and then calculates the average inlet temperature and the indoor unit. The deviation 2 is calculated based on the inlet temperature detected by the inlet temperature sensor of the indoor heat exchanger (B1) (S301).

In addition, the outdoor controller 40 calculates the deviation 3 based on the current compressor capacity (operation frequency) and the previous compressor capability (operation frequency) (S302).

In addition, the outdoor controller 40 determines the deviation 4 based on the intermediate temperature detected by the intermediate temperature sensor of the indoor heat exchanger of the indoor unit B1 and the intermediate temperature detected by the inlet temperature sensor of the indoor heat exchanger of the indoor unit B1. It is calculated (S303).

Accordingly, the outdoor controller 40 substitutes the calculated deviation 1, d deviation 1, deviation 2, deviation 3, and deviation 4 into (Eq. 3), and then sets E, D, The output step of the electric expansion valve 13 of the indoor unit B1 is determined in consideration of C, the weight 1, the weight 2, the weight 3, and the weight 4 (S304). On the other hand, the method of determining the output step of the electric expansion valve 14 of the indoor unit B2 is the same as the method of determining the output step of the electric expansion valve 13 of the indoor unit B1 mentioned above.

When the output steps of the motor-expansion valves 13 and 14 are determined in this way, the outdoor controller 40 adds the output steps determined to the previous output steps, and the opening degree of the motor-expansion valves 13 and 14 is summed. Control (S305). At this time, the output step 0 is a state in which the opening degree of the electric expansion valve is completely closed, and the output step 480 is a state in which the opening degree of the electric expansion valve is completely opened.

FIG. 7 is a flowchart illustrating a method of controlling the opening degree of the electric expansion valve based on an average temperature obtained by averaging the discharge temperature of the compressor and the intermediate temperature of the indoor heat exchanger during heating operation. ) And the operation of controlling the opening degree of the electric expansion valve 13 of the indoor unit B1 when two rooms are operated for the indoor unit B2.

With reference to FIG. 7, the output step of the electric expansion valve 13 at the time of heating is computed based on (Equation 4) below.

Output step = (deviation 1 × E + d deviation 1 × D) × weight 1 + (deviation 5 × C) × weight 2 + (deviation 3 × weight 3) + (deviation 4 × weight 4) ----- ( Equation 4

Where deviation 1 = discharge temperature (T_dis) -target discharge temperature (T_d_c) of the compressor,

d deviation 1 = current deviation 1-previous deviation 1,

Deviation5 = medium temperature of the indoor heat exchanger of the indoor unit B1 [(Teva_mid, a + Teva_mid, b) / 2]-mean temperature of the indoor heat exchanger of the indoor unit B1 (Teva_mid, a),

Deviation3 = capacity of current compressor (Cf)-capacity of previous compressor (Cf),

Deviation 4 = middle temperature (Teva_mid, a) of indoor heat exchanger of indoor unit (B1)-inlet temperature (Teva_in, a) of indoor heat exchanger of indoor unit (B1),

E, D, C, weight 1, weight 2, weight 3, weight 4 is a constant determined according to the number of operating units of the indoor unit during heating as shown in FIG.

The outdoor controller 40 calculates the deviation 1 from the discharge temperature of the compressor 10 detected by the discharge temperature sensor 16 of the compressor and the target discharge temperature during heating calculated by equation (2). When the calculation for the deviation 1 is completed, the outdoor controller 40 calculates the d deviation 1 using the previous deviation and the current deviation for the deviation 1 (S310).

The outdoor controller 40 averages the intermediate temperatures detected by the intermediate temperature sensor of the indoor heat exchanger of the indoor unit B1 and the intermediate temperature sensor of the indoor heat exchanger of the indoor unit B2, and the average intermediate temperature and the indoor unit B1. Deviation 5 is calculated based on the intermediate temperature of the indoor heat exchanger (S311).

The outdoor controller 40 calculates the deviation 3 based on the current compressor operating frequency and the previous compressor operating frequency (S312).

Accordingly, the outdoor controller 40 substitutes the calculated deviation 1, d deviation 1, deviation 5, and deviation 3 into (Equation 4) and then sets E in advance according to the number of operating units of the indoor unit heated as shown in FIG. 4. The output step of the electric expansion valve 13 of the indoor unit B1 is determined in consideration of, D, C, weight 1, weight 2, and weight 3 (S313). At this time, the inequality of the refrigerant can be solved by considering the deviation 5. That is, if the refrigerant is excessively concentrated in one indoor heat exchanger, the indoor heat exchanger in which the refrigerant is concentrated becomes higher than the intermediate temperature in the indoor heat exchanger in which the refrigerant is relatively insufficient as the pressure increases. Accordingly, when the average value of the intermediate temperature is taken and controlled, the control of the motor expansion valve is narrowed in the indoor heat exchanger having a high intermediate temperature, so that the intermediate temperature is lowered, and the motor expansion valve is widened in the indoor heat exchanger having a low intermediate temperature. The intermediate temperature is increased to solve the unbalance of the refrigerant in each indoor unit. On the other hand, the method of controlling the opening degree of the electric expansion valve 14 of the indoor unit B2 is the same as the method of controlling the opening degree of the electric expansion valve 13 of the indoor unit B1 mentioned above.

When the output steps of the motor-expansion valves 13 and 14 are determined in this way, the outdoor controller 40 controls the opening degree of the motor-expansion valves 13 and 14 by summing the output steps determined to the previous output step (S314). ).

As described in detail above, the present invention is directed to various operating conditions such as cooling / heating operation, single-room / multi-room operation, sudden compressor capacity change, indoor temperature and outdoor temperature change in a multi-room air conditioner to which a variable capacity compressor is applied. The compressor can be operated in an optimal state, thereby improving the reliability of the compressor.

Enumerating the advantages of the present invention can be summarized as follows.

First, the opening degree control of the electric expansion valve is made by reflecting the target discharge temperature that satisfactorily satisfies the suction superheat of the compressor according to the required capacity of each indoor unit, and the difference between the compressor discharge temperature and the target discharge temperature is the width of the change of temperature. Since it is wide, it is much easier to finely adjust the opening degree of the electric expansion valve.

In the multi-room operation, even if the indoor air temperature of each indoor unit is in a different operating condition, the average temperature of the inlet temperature of each indoor heat exchanger is taken to control the opening degree of the electric expansion valve. The inlet temperature of the air is lowered, and the inlet temperature of the indoor heat exchanger of the indoor unit having a low indoor air temperature is increased to actively respond to the air conditioning load of the indoor unit.

In addition, by controlling the inlet temperature and the outlet temperature of the indoor heat exchanger together, it is possible to prevent excessive refrigerant from flowing to the indoor unit side heat exchanger having a low load, and to prevent the shortage of refrigerant in which a small amount of refrigerant is supplied to the indoor heat exchanger side having a high load. Can be.

In addition, since the opening degree of the electric expansion valve is controlled in consideration of the change of the output frequency of the compressor, when the capacity of the compressor is changed from the minimum to the maximum, the opening degree of the electric expansion valve is adjusted within a short time to improve the reliability and cycle state of the compressor. It can be optimally secured.

Claims (19)

A plurality of indoor units are connected to one outdoor unit, the outdoor unit has a compressor and an outdoor heat exchanger, and each indoor unit has an indoor heat exchanger, and an electric motor for controlling a flow rate of a refrigerant to a refrigerant pipe connected between the outdoor heat exchanger and each indoor heat exchanger. In the multi-room air conditioner provided with an expansion valve, Compressor discharge temperature detection means for detecting a discharge temperature of the compressor; And Determine a target discharge temperature of the compressor for optimally satisfying the suction superheat degree of the compressor according to the required capability of the indoor unit, and based on the difference between the discharge temperature detected by the compressor discharge temperature detection means and the target discharge temperature. A multi-room air conditioner, comprising control means for controlling the opening degree of the electric expansion valve. The multi-room air conditioner according to claim 1, further comprising: an outdoor temperature detecting means for detecting an outdoor temperature and an indoor temperature detecting means for detecting an indoor temperature of the indoor unit. 3. The multi-room air according to claim 2, wherein the control means calculates a target discharge temperature of the compressor based on the capacity (operating frequency) of the compressor determined according to the outdoor temperature, the indoor temperature, and the required capacity of the indoor unit. Conditioner. 4. The multi-room air conditioner according to claim 3, wherein the control means calculates different target discharge temperatures according to the operation mode of the air conditioner. 5. The multi-room air conditioner according to claim 4, wherein the control means calculates a target discharge temperature (T_d_c) by the following expression (1) in the cooling mode. T_d_c = (C1 × Cf) + (To-35) × C2 + (27-Ti) × C3 + C4 ----- (Equation 1) Where Cf is the compressor's capacity (operating frequency) according to the required capacity from the indoor unit in operation, To is the outdoor temperature, Ti is the average indoor temperature of the indoor unit in operation, and 35 and 27 are the upper limit values of the outdoor and indoor temperatures, respectively. As an example, C1, C2, C3, and C4 are constants determined according to the number of driving units of the indoor unit. 5. The multi-room air conditioner according to claim 4, wherein the control means calculates a target discharge temperature (T_d_c) by the following expression (2) in the heating mode. T_d_c = (C1 × Cf) + (To-7) × C2 + (Ti-20) × C3 + C4 ----- (Equation 2) Where Cf is the compressor's capacity (operating frequency) according to the required capacity from the indoor unit in operation, To is the outdoor temperature, Ti is the average indoor temperature of the indoor unit in operation, and 7 and 20 are the lower limit values of the outdoor and indoor temperatures, respectively. As an example, C1, C2, C3, C4 are constants determined according to the number of driving units of the indoor unit. 2. The multi-use of claim 1, wherein the control means performs control to widen the opening degree of the electric expansion valve when the discharge temperature of the compressor detected by the compressor discharge temperature detection means is higher than the target discharge temperature. Air conditioner. The multi-room of claim 1, further comprising: inlet temperature detecting means for detecting a temperature of an inlet region of each indoor heat exchanger and an intermediate temperature detecting means for detecting a temperature of an intermediate region of the indoor heat exchanger. Air conditioner. The method of claim 8, wherein in the cooling mode, the control means further considers a difference between the intermediate temperature of the intermediate region detected by the intermediate temperature detecting means and the inlet temperature of the inlet region detected by the inlet temperature detecting means. A multi-room air conditioner, characterized by controlling the opening degree of the electric expansion valve. 2. An outdoor temperature detecting means for detecting an outdoor temperature, an indoor temperature detecting means for detecting an indoor temperature of an indoor unit, an inlet temperature detecting means for detecting a temperature of an inlet area of the indoor heat exchanger, and the indoor unit. A multi-room air conditioner, further comprising an intermediate temperature detecting means for detecting a temperature of an intermediate region of the heat exchanger. 11. The air conditioner of claim 10, wherein the control unit calculates a target discharge temperature of the compressor based on the capacity (operating frequency) of the compressor determined according to the outdoor temperature, the indoor temperature, and the required capability of the indoor unit. The opening degree of the electric expansion valve is controlled by further considering the difference between the average temperature obtained by averaging the inlet temperature of the heat exchanger and the inlet temperature of the indoor heat exchanger, and the difference between the intermediate temperature and the inlet temperature of the indoor heat exchanger. Tea room air conditioners. 12. The multi-room air according to claim 11, wherein the control means controls the opening degree of the electric expansion valve by an output step calculated by the following equation (3) when one or more indoor units are simultaneously operated in a cooling operation. Harmonizer. Output Step = (Deviation 1 × E + d Deviation 1 × D) × Weight 1 + (Deviation 2 × C) × Weight 2 + (Deviation 3 × Weight 3) + (Deviation 4 × Weight 4) ----- ( Equation 3 Where deviation 1 = discharge temperature of the compressor (T_dis)-target discharge temperature (T_d_c), d deviation 1 = current deviation 1-previous deviation 1, Deviation 2 = average inlet temperature of the indoor heat exchanger [(Teva_in, a + Teva_in, b) / 2]-inlet temperature of the indoor heat exchanger of the indoor unit B1 (Teva_in, a), Deviation3 = capacity of current compressor (Cf)-capacity of previous compressor (Cf), Deviation 4 = middle temperature of indoor heat exchanger of controlled indoor unit (Teva_mid, a)-inlet temperature of indoor heat exchanger of controlled indoor unit (Teva_in, a), E, D, C, weight 1, weight 2, weight 3, and weight 4 are constants determined according to the number of operating units of the indoor unit during cooling. The method of claim 10, wherein the control means calculates the target discharge temperature of the compressor based on the operating frequency of the compressor determined according to the outdoor temperature, the indoor temperature and the required capability of the indoor unit, and in the heating mode of the indoor heat exchanger A multi-room air conditioner for controlling the opening degree of the electric expansion valve in consideration of the difference between the average temperature of the inlet temperature and the inlet temperature of the indoor heat exchanger. 14. The multi-room air according to claim 13, wherein the control means controls the opening degree of the electric expansion valve by an output step calculated by the following Equation (4) when one or more indoor units are a multi-room operation in which heating operation is performed simultaneously. Harmonizer. Output step = (deviation 1 × E + d deviation 1 × D) × weight 1 + (deviation 5 × C) × weight 2 + (deviation 3 × weight 3) + (deviation 4 × weight 4) ----- ( Equation 4 Where deviation 1 = discharge temperature (T_dis) -target discharge temperature (T_d_c) of the compressor, d deviation 1 = current deviation 1-previous deviation 1, Deviation5 = mean median temperature of the indoor heat exchanger of the controlled indoor unit [(Teva_mid, a + Teva_mid, b) / 2]-median temperature of the indoor heat exchanger of the controlled indoor unit (Teva_mid, a), Deviation3 = capacity of current compressor (Cf)-capacity of previous compressor (Cf), E, D, C, weight 1, weight 2, weight 3, weight 4 are constants determined according to the number of operating units of the indoor unit during heating. A plurality of indoor units are connected to one outdoor unit, the outdoor unit has a compressor and an outdoor heat exchanger, and each indoor unit has an indoor heat exchanger, and an electric motor for controlling a flow rate of a refrigerant to a refrigerant pipe connected between the outdoor heat exchanger and each indoor heat exchanger. In the multi-room air conditioner provided with an expansion valve, Temperature detecting means for detecting a temperature of an inlet region and an intermediate region of the indoor heat exchanger; And The difference between the average temperature averaged by the inlet temperature of the indoor heat exchanger detected by the temperature detecting means and the inlet temperature of the corresponding indoor heat exchanger corresponding to the electric expansion valve to be controlled, and the intermediate temperature and the inlet temperature of the indoor heat exchanger. And a control means for controlling the opening degree of the electric expansion valve to be controlled based on the difference between the two. 16. The multi-room air conditioner according to claim 15, wherein the control means performs a control to widen the opening degree of the electric expansion valve to be controlled when the average temperature is higher than the inlet temperature. A plurality of indoor units are connected to one outdoor unit, the outdoor unit has a compressor and an outdoor heat exchanger, and each indoor unit has an indoor heat exchanger, and an electric motor for controlling a flow rate of a refrigerant to a refrigerant pipe connected between the outdoor heat exchanger and each indoor heat exchanger. In the multi-room air conditioner provided with an expansion valve, Compressor discharge temperature detection means for detecting a discharge temperature of the compressor; Temperature detecting means for detecting temperatures of an inlet region and an intermediate region of the indoor heat exchanger, respectively; And The target discharge temperature of the compressor that satisfactorily satisfies the suction superheat degree of the compressor according to the required capability of each indoor unit is determined according to the operation mode, The difference between the discharge temperature detected by the compressor discharge temperature detection means and the target discharge temperature determined to correspond to the cooling mode in the cooling mode, the difference between the intermediate temperature and the inlet temperature of the indoor heat exchanger detected by the temperature detection means, And controlling the opening degree of the electric expansion valve based on the average temperature obtained by averaging the inlet temperature of the indoor heat exchanger. In the heating mode, the difference between the discharge temperature detected by the compressor discharge temperature detection means and the target discharge temperature determined to correspond to the heating mode, and the inlet temperature of the indoor heat exchanger detected by the temperature detection means are averaged. And a control means for controlling the opening degree of the electric expansion valve on the basis of the plurality of air conditioners. 18. The multi-room air according to claim 17, wherein the control means calculates a target discharge temperature of the compressor based on the capacity (operating frequency) of the compressor determined according to the outdoor temperature, the indoor temperature, and the required capacity of the indoor unit. Harmonizer. The method of claim 17, The control means controls the opening degree of the electric expansion valve further considering the difference between the capacity of the compressor in the current control period (operation frequency) and the capacity of the compressor in the previous control period (operation frequency). Air conditioner.