KR100403023B1 - Outdoor fan control system of air conditioner and control method thereof - Google Patents

Abstract

The air conditioner of the present invention includes an outdoor unit 8 and an indoor unit 9. The outdoor unit 8 includes a compressor 2 and an outdoor heat exchanger 3 controlled by a pulse width modulation method, and further includes a first outdoor fan 30 and a second outdoor fan installed near the outdoor heat exchanger 3. 31). The first outdoor fan 30 and the second outdoor fan 31 are installed side by side to allow the external air to pass through the outdoor heat exchanger 3 to allow heat exchange in the outdoor heat exchanger 3. The operation mode of the first outdoor fan 30 and the second outdoor fan 31 is determined according to the amount of refrigerant discharged from the compressor 2 and external conditions. An outdoor temperature sensor 33 for measuring the outdoor temperature is connected to an input port of the outdoor controller 27 and drives the first outdoor fan 30 and the second outdoor fan 31, respectively. 34 and the second outdoor fan driver 35 are connected to the output port of the outdoor controller 27. The outdoor controller 27 checks the outdoor temperature data input from the outdoor temperature sensor 33 and the loading time of the compressor 2 to control the first outdoor fan driver 34 and the second outdoor fan driver 35. The first outdoor fan 30 and the second outdoor fan 31 are driven in a predetermined operation mode.

Description

Outdoor fan control system of air conditioner and control method thereof

The present invention relates to an air conditioner, and more particularly, to an outdoor fan control system of an air conditioner employing a pulse width modulation compressor and a control method thereof.

In the air conditioner, the condenser, that is, the outdoor heat exchanger, is installed in the outdoor unit and serves to condense the refrigerant by releasing heat to the surroundings. At this time, the heat exchange amount in the outdoor heat exchanger is changed according to the rotational speed of the blower fan and the outdoor temperature, and the change in the heat exchange amount directly affects the cooling capacity of the indoor unit.

In particular, when the outdoor temperature is low, the heat exchange amount in the outdoor heat exchanger increases because the temperature difference between the refrigerant and the outdoor air is large. As a result, the evaporator temperature of the refrigerant in the evaporator, i.e., the indoor heat exchanger, may be lowered, and the surface of the indoor heat exchanger may be frozen. In this case, the cooling capacity of the indoor unit is reduced.

On the other hand, when the outdoor temperature is high, since the temperature difference between the refrigerant and the outdoor air is small, the heat exchange amount in the outdoor heat exchanger is reduced. Therefore, the evaporation temperature is increased in the indoor heat exchanger, and thus the heat exchange amount of the refrigerant in the indoor heat exchanger is reduced, thereby lowering the cooling capacity of the indoor unit.

Therefore, it is necessary to appropriately adjust the heat exchange amount in the outdoor heat exchanger in accordance with the change of the outdoor temperature in order to always maintain the best cooling capacity of the indoor unit regardless of the outdoor temperature.

To this end, in the conventional air conditioner, the rotation speed of the outdoor fan is adjusted to two stages of high speed and low speed according to the height of the outdoor temperature. This is the same in the case of a plurality of outdoor fans as well as a single case. That is, when the outdoor temperature is low, a plurality of outdoor fans were simultaneously operated at a low speed to reduce the heat exchange amount in the outdoor heat exchanger. When the outdoor temperature is high, the plurality of outdoor fans were operated to increase the heat exchange amount in the outdoor heat exchanger. Outdoor fans were operated at high speed simultaneously.

However, according to the conventional method of controlling the outdoor fan of the air conditioner as described above, since the outdoor fan is controlled by considering only the outdoor temperature, the refrigerant compression and discharge amount vary with time, such as an inverter compressor or a PWM compressor. There is a problem that the heat exchange amount in the outdoor heat exchanger cannot always be constantly adjusted.

In particular, in the case of the PWM compressor, the refrigerant is discharged periodically or intermittently even during operation of the compressor. That is, during operation of the compressor, since the loading with the discharge of the refrigerant and the unloading without the discharge of the refrigerant occur alternately, the compression amount and the discharge amount of the refrigerant change with time, and thus the refrigerant flowing through the outdoor heat exchanger The amount changes. That is, when the loading time is relatively small, the amount of refrigerant flowing to the outdoor heat exchanger is also relatively small. At this time, if the rotational speed of the outdoor fan is constant, the heat exchange is relatively excessive compared to the amount of the refrigerant flowing through the outdoor heat exchanger. Therefore, the cooling capacity of the indoor unit is lowered due to the supercooling of the refrigerant. On the other hand, when the loading time is relatively large, the amount of the refrigerant flowing to the outdoor heat exchanger is also relatively high. At this time, if the rotational speed of the outdoor fan is constant, the heat exchange is relatively insufficient compared to the amount of the refrigerant flowing through the outdoor heat exchanger. Therefore, the cooling capacity of the indoor unit is lowered due to the increase in the condensation pressure of the refrigerant.

SUMMARY OF THE INVENTION The present invention has been made under the above-mentioned background. In an air conditioner employing a compressor controlled by a pulse width modulation method, an outdoor unit that can adequately control the cooling capacity of an indoor unit by appropriately adjusting the amount of heat exchange in an outdoor heat exchanger. An object of the present invention is to provide a fan control system and a control method thereof.

1 is a cycle configuration diagram of an outdoor fan control system of an air conditioner according to the present invention.

Figure 2a shows a loading state of the PWM compressor employed in the air conditioner of the present invention, Figure 2b shows an unloading state.

FIG. 3 illustrates a relationship between loading and unloading and a refrigerant discharge amount during operation of the compressor of FIG. 2.

4 is a block diagram of an outdoor fan control system of the air conditioner according to the present invention.

5 is a flowchart illustrating a method of controlling an outdoor fan of an air conditioner according to the present invention.

* Description of symbols on the main parts of the drawings *

2: compressor 5: indoor heat exchanger

8: outdoor unit 9: indoor unit

26: PWM valve 27: outdoor control unit

28: outdoor communication circuit unit 29: indoor control unit

30: first outdoor fan 31: second outdoor fan

33: outdoor temperature sensor

In order to achieve the above object, the air conditioner outdoor fan control system of the present invention includes: a compressor in which a discharge amount of a refrigerant may vary during operation, an outdoor heat exchanger connected to the compressor, an outdoor fan installed in the vicinity of the outdoor heat exchanger, and outdoor An outdoor temperature sensor for sensing a temperature, a control unit for controlling the operation of the outdoor fan in a predetermined operation mode according to the outdoor temperature sensed by the outdoor temperature sensor and the refrigerant discharge amount of the compressor.

In addition, the air conditioner outdoor fan control method of the present invention, the outdoor fan control method of the air conditioner having a compressor controlled by the pulse width modulation method, detecting the outdoor temperature, detecting the loading time of the compressor, And operating the outdoor fan in a predetermined operation mode based on the outdoor temperature detected in the step and the loading time of the compressor.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; 1 is a cycle configuration diagram of an air conditioner according to the present invention. The air conditioner (1) of the present invention includes a compressor (2), an outdoor heat exchanger (3), an electric expansion valve (4), and an indoor heat exchanger (5) sequentially connected by a refrigerant pipe to form a closed circuit. . Among the refrigerant pipes, the refrigerant pipe connecting the discharge side of the compressor 2 and the inflow side of the electric expansion valve 4 is a high pressure tube 6 for guiding the flow of the high pressure refrigerant discharged from the compressor 2, and the electric expansion valve ( The refrigerant pipe connecting the outlet side of 4) and the suction side of the compressor 2 is a low pressure tube 7 for guiding the flow of the low pressure refrigerant expanded by the electric expansion valve 4. The outdoor heat exchanger 3 is installed in the middle of the high pressure pipe 6, and the indoor heat exchanger 5 is installed in the middle of the low pressure pipe 7. When the compressor 2 operates, the refrigerant flows in the direction of the solid arrow.

Meanwhile, the air conditioner 1 of the present invention includes an outdoor unit 8 and an indoor unit 9. The outdoor unit 8 includes the compressor 2 and the outdoor heat exchanger 3 described above, and includes a high pressure downstream of the accumulator 10 and the outdoor heat exchanger 3 installed in the low pressure pipe 7 upstream of the compressor 2. And a receiver 11 installed in the tube 6. The accumulator 10 collects and vaporizes the liquid refrigerant which failed to evaporate in the indoor heat exchanger 5 to be introduced into the compressor 2. That is, when the evaporator 10 does not completely evaporate, the refrigerant entering the accumulator 10 is a mixture of liquid and gaseous state, and the accumulator 10 vaporizes the liquid refrigerant to form a gaseous refrigerant (gas refrigerant). Only allow suction to the compressor. To this end, the refrigerant pipe inlet end and the refrigerant pipe outlet end of the accumulator 10 are preferably located above the accumulator 10.

Similarly, when complete condensation is not performed in the outdoor heat exchanger 3, the refrigerant entering the receiver 11 is a mixture of a liquid phase and a gaseous phase. The receiver 11 is configured to separate the liquid refrigerant and the gaseous refrigerant so that only the liquid refrigerant flows out. For this purpose, the refrigerant pipe inlet and outlet ends of the receiver 11 extend to the lower side of the receiver 11.

In order to bypass the gaseous refrigerant inside the receiver 11, a vent bypass pipe 12 is provided which connects the receiver 11 and the low pressure pipe 7 upstream of the accumulator 10. The inlet end of the vent bypass tube 12 is provided above the receiver 11 to allow only the gaseous refrigerant to flow therein, and a vent valve 13 is provided to adjust the bypassing of the gaseous refrigerant inside the receiver 11. do. Therefore, the gas refrigerant inside the receiver 11 flows in the direction of the double-dotted arrow by the operation of the vent valve 13.

The high pressure tube exiting the receiver 11 is configured to pass through the accumulator 10. This is for vaporizing a low temperature liquid refrigerant in the accumulator 10 by using a refrigerant of a relatively high temperature passing through the high pressure tube. In order to effectively perform vaporization in the accumulator 10, the low pressure refrigerant tube inside the accumulator 10 is formed in a U shape, and the high pressure refrigerant tube passing through the accumulator 10 is arranged to pass through the inside of the U type low pressure refrigerant tube. do.

In addition, the outdoor unit 8 is an accumulator downstream of the hot gas bypass pipe 14 and the receiver 11 that connect the accumulator 10 and the high pressure pipe 6 from the compressor 2 to the outdoor heat exchanger 3. And a liquid bypass pipe 15 for connecting the upstream of the radar 10. A hot gas valve 16 is installed in the middle of the hot gas bypass pipe 14 to adjust the flow rate of the bypassed hot gas. The liquid valve 17 is installed in the middle of the liquid bypass pipe 15 to adjust the flow rate of the liquid refrigerant to be bypassed. Therefore, when the hot gas valve 16 is opened, a part of the hot gas from the compressor 2 flows along the hot gas bypass pipe 14 in the direction of the dashed arrow, and when the liquid valve 17 is opened, the receiver 11 A part of the liquid refrigerant which flows out flows along the liquid bypass pipe 15 in the direction of a dashed-dotted arrow.

Meanwhile, the outdoor unit 8 includes a first outdoor fan 30 and a second outdoor fan 31 installed near the outdoor heat exchanger 3. The first outdoor fan 30 and the second outdoor fan 31 are installed side by side to allow the external air to pass through the outdoor heat exchanger 3 to allow heat exchange in the outdoor heat exchanger 3. The operation mode of the first outdoor fan 30 and the second outdoor fan 31 is determined according to the amount of refrigerant discharged from the compressor 2 and external conditions. This will be described later. The outdoor unit 8 also includes an outdoor temperature sensor 33 for measuring the outdoor temperature.

Several indoor units 9 are arranged in parallel, and each indoor unit 9 includes an electric expansion valve 4 and an indoor heat exchanger 5. Therefore, a plurality of indoor units 9 are connected to one outdoor unit 8. The capacity and shape of each indoor unit 9 may be the same or different.

As shown in Figs. 2A and 2B, a variable capacity compressor 2 controlled by a pulse width modulation method is used as the compressor. The compressor (2) has a casing (20) provided with an inlet (18) and an outlet (19), a motor (21) provided inside the casing (20), and a rotating scroll (22) rotating under the rotational force of the motor (21). ) And a fixed scroll (24) for forming a compression chamber (23) between the orbiting scroll (22). The casing 20 is provided with a bypass tube 25 connecting the upper side of the fixed scroll 24 and the inlet 18, and the bypass tube 25 has a PWM valve in the form of a solenoid valve; 26) is installed. Fig. 2A shows a state where the PWM valve 26 is turned off to block the bypass pipe 25. In this state, the compressor 2 discharges the compressed refrigerant. This state is called loading, and the compressor 2 operates at a capacity of 100%. 2B illustrates a state in which the PWM valve 26 is turned on to open the bypass pipe 25, in which the refrigerant is not discharged from the compressor 2. This state is called unloading and the compressor 2 is operated at a capacity of 0%. The compressor 2 is supplied with power, whether loaded or unloaded, and the motor 21 rotates at a constant speed. When the power supply to the compressor 2 is cut off, the motor 21 does not rotate and the operation of the compressor 2 is stopped.

As shown in Fig. 3, the compressor 2 repeats loading and unloading at regular intervals during operation. In each cycle, the loading time and the unloading time vary depending on the cooling demand. In the loading time, the compressor 2 discharges the refrigerant, so that the temperature of the indoor heat exchanger 5 drops and the compressor 2 at the unloading time. Does not discharge the refrigerant, the temperature of the indoor heat exchanger (5) rises. In FIG. 3, the area of the hatched portion represents the amount of refrigerant discharged. The signal controlling the loading time and the unloading time is called a duty control signal. In the embodiment of the present invention, the period is set to, for example, 20 seconds and takes a manner of varying the capacity of the compressor 2 by varying the loading time and the unloading time according to the total cooling demand of the indoor unit 9. .

4 is a block diagram of an air conditioner control system according to the present invention. As shown in FIG. 4, the outdoor unit 8 includes an outdoor controller 27 connected to the compressor 2 and the PWM valve 26 to enable signal transmission. The outdoor controller 27 is connected to the outdoor communication circuit 28 to transmit and receive data. In addition, the outdoor temperature sensor 33 is connected to the input port of the outdoor control unit 27, the first outdoor fan drive unit 34 and the second to drive the first outdoor fan 30 and the second outdoor fan 31, respectively The outdoor fan driver 35 is connected to the output port of the outdoor controller 27. The outdoor controller 27 checks the outdoor temperature data input from the outdoor temperature sensor 33 and the loading time of the compressor 2 to control the first outdoor fan driver 34 and the second outdoor fan driver 35. The first outdoor fan 30 and the second outdoor fan 31 are driven in a predetermined operation mode.

Each indoor unit 9 includes an indoor communication circuit 32 that is capable of transmitting and receiving data between the indoor control unit 29 and the outdoor unit 8. The outdoor communication circuit unit 28 and the indoor communication circuit unit 32 are provided to enable data transmission and reception by wire or wirelessly. The temperature detection unit 30 and the temperature setting unit 31 are connected to the input port of the indoor control unit 29, and the electric expansion valve 4 is connected to the output port. The temperature detector 30 is a temperature sensor for sensing the temperature of the room, which is a harmonic space. The indoor control unit 29 receives signals from the temperature detecting unit 30 and the temperature setting unit 31 and calculates the cooling demand capability of the indoor unit 9 based on the difference between the indoor temperature and the set temperature. The loading time of the compressor 2 is determined according to the cooling demand capability thus calculated.

The first outdoor fan 30 and the second outdoor fan 31 each have three operation modes: a stop mode, a low speed mode, and a high speed mode. The operation mode by the combination of the two fans is as follows.

TABLE 1

mode First outdoor fan 2nd outdoor fan 5 high speed high speed 4 sleaze high speed 3 sleaze sleaze 2 stop high speed One stop sleaze 0 stop stop

That is, there are six operation modes by combining two fans. In this embodiment, two fans are used, but only one fan can be used. In this case, the operation modes are three types: stop, low speed, and high speed.

The above operation mode is predetermined according to the outdoor temperature and the loading time of the compressor (2). Table 2 shows the operation mode according to the outdoor temperature and the loading time when the duty cycle control cycle of the 7.5 horsepower compressor 2 is 20 seconds.

TABLE 2

Outdoor temperature Loading time 7 ℃ or less 8-12 ℃ 13 ~ 17 ℃ 18 ~ 22 ℃ 23 ~ 27 ℃ 28 ℃ or more 10 seconds or more 0 2 3 4 5 5 5 to 9 seconds 0 One 2 3 4 5 4 seconds or less 0 0 One 2 3 5

As can be seen in Table 2 above, the operation mode is the first outdoor fan 30 and the first outdoor fan 30 and the higher the loading time of the compressor 2 (the longer the compressor loading time, the greater the amount of refrigerant discharged from the compressor). It is set in the direction of increasing the rotational speed of the two outdoor fans (31).

An outdoor fan control process will be described with reference to FIG. 5. First, when the operation of the compressor 2 starts, the outdoor controller 27 receives the outdoor temperature and the loading time of the compressor (S101). The outdoor temperature is detected by the outdoor temperature sensor 33, and when the compressor 2 is operated, the outdoor controller 27 has information about the loading time of the compressor 2. Next, the operation mode is selected according to the outdoor temperature and the loading time of the compressor (S102). The operation mode is selected from one of six modes as predetermined as shown in Table 2.

Next, before performing the selected operation mode, it is determined whether the first outdoor fan 30 or the second outdoor fan 31 is in the stopped state (S103), and the first outdoor fan 30 or the second outdoor fan 31 is determined. If the fan is in the stopped state, the outdoor fan is operated at high speed regardless of the selected operation mode (S104). That is, if both the 1st outdoor fan 30 and the 2nd outdoor fan 31 were in the stopped state, it will drive in the mode 5. As shown in FIG. This is to reinforce the power at the start of the outdoor fan drive motor and this operation is continued for 2 to 5 seconds (preferably 3 seconds).

If it is determined in step 103 that the outdoor fan is not in a stopped state or 3 seconds have elapsed in step 104, the outdoor fan is operated in the operation mode selected in step 102 (S105). For example, when the outdoor temperature is 7 ° C. or less, 0 mode is selected regardless of the loading time of the compressor 2, and in the 0 mode, both the first outdoor fan 30 and the second outdoor fan 31 are stopped. In this state, if the outdoor temperature is 15 ℃ and the loading time of the compressor is 12 seconds, the operation mode is selected as 3 mode according to Table 2. However, the first outdoor fan 30 and the second outdoor fan 31 are driven at a high speed for three seconds instead of driving the outdoor fan in the selected three operation mode immediately, and then operated in the selected three mode. Accordingly, the first outdoor fan 30 and the second outdoor fan 31 are both switched from the high speed mode to the low speed mode.

As described in detail above, according to the outdoor fan control system and the control method of the air conditioner according to the present invention, the outdoor heat exchange by controlling the outdoor fan in consideration of the loading time and the outdoor temperature of the compressor controlled by the pulse width modulation method It is possible to appropriately adjust the amount of heat exchange in the machine, and thus the cooling capacity of the indoor unit can be properly exhibited.

Claims (11)

A compressor in which a loading time for discharging the refrigerant and an unloading time for discharging the refrigerant are repeated during operation, and the loading time and the unloading time are controlled by a pulse width modulation method so that the discharge amount of the refrigerant can be varied; An outdoor heat exchanger connected to the compressor, An outdoor fan installed near the outdoor heat exchanger, Outdoor temperature sensor for sensing outdoor temperature, And a control unit for controlling the operation of the outdoor fan in a predetermined operation mode according to the outdoor temperature sensed by the outdoor temperature sensor and the refrigerant discharge amount of the compressor estimated by the loading time. In claim 1, The operation mode is an air conditioner outdoor fan control system, characterized in that the higher the outdoor temperature is set in the direction of increasing the rotational speed of the outdoor fan as the refrigerant discharge amount of the compressor increases. In claim 1, The outdoor fan is one, the operation mode is an air conditioner outdoor fan control system including a stop mode, a low speed mode, a high speed mode. In claim 1, The outdoor fan includes two fans whose operation modes are a stop mode, a low speed mode, and a high speed mode, respectively, and a combination of the operation modes of the two fans includes stop-stop, stop-low speed, stop-high speed, low-speed, An air conditioner outdoor fan control system comprising low speed-high speed and high speed-high speed. delete In claim 1, And the compressor and the outdoor heat exchanger constitute an outdoor unit, wherein the expansion valve and the indoor heat exchanger constitute an indoor unit, and a plurality of the indoor units are arranged in parallel. An outdoor fan control method of an air conditioner having a compressor controlled by a pulse width modulation method, Detecting the outdoor temperature, Detecting a loading time of the compressor; And operating the outdoor fan in a predetermined operation mode based on the outdoor temperature detected in the step and the loading time of the compressor. In claim 7, The operation mode is an air conditioner outdoor fan control method, characterized in that the higher the outdoor temperature is set in the direction of increasing the rotation speed of the outdoor fan as the loading time increases. In claim 8, The operation mode of the outdoor fan includes a stop mode, a low speed mode, and a high speed mode. When the operation mode of the outdoor fan is changed from the stop mode to another mode, the outdoor fan is operated in the high speed mode for a predetermined time and then switched to the corresponding mode. Air conditioner outdoor fan control method, characterized in that. In claim 9, The predetermined time is 2 to 5 seconds, the air conditioner outdoor fan control method. In claim 7, The outdoor fan includes two fans whose operation modes are a stop mode, a low speed mode, and a high speed mode, respectively, and the operation modes of the two fans include stop-stop, stop-low speed, stop-high speed, and low speed of the two fans. -The air conditioner outdoor fan control system, characterized in that performed in six stages at low speed, low speed-high speed, high speed-high speed.