KR100496553B1 - Control Method of Multi-Compressor for Air- Conditioner - Google Patents

Abstract

The present invention relates to a multi-compressor control method for an air conditioner, comprising: determining an initial starting state and an indoor load of a multi-compressor according to a mutual relationship between an outdoor temperature and a predetermined reference temperature section; Simultaneously operating the multi-compressors based on the determined indoor load; And switching the multi-compressor in the order of alternating operation and single operation based on the tendency according to the time difference when the multi-compressor is simultaneously operated.

As described above, the present invention selects simultaneous operation, alternating operation and single operation based on the tendency according to the time difference when the multi-compressor is operated, so that the load fluctuation range of the multi-compressor is not great even when the outdoor temperature is severely changed, and power consumption is required. Can be relatively reduced, while efficiently operating the air conditioner.

Description

Control Method of Multi-Compressor for Air-Conditioner

The present invention relates to a multi-compressor control method for an air conditioner, and more particularly, when controlling a multi-compressor using two or more compressors, simultaneous operation, alternating operation and By selecting a single operation, the present invention relates to a control method for a multi-compressor for an air conditioner, which can relatively reduce power consumption and efficiently operate an air conditioner.

As is well known, air conditioners such as air conditioners are classified into wall-mounted air conditioners and stand-type air conditioners according to the installation method. It is divided into one separate air conditioner.

Among these air conditioners, a drawing of an air conditioner in which a indoor unit and an outdoor unit are separately separated from a stand-type air conditioner, and a drawing related to a refrigeration cycle, are shown in FIGS. 1 and 2.

As shown, a typical air conditioner is composed of an outdoor unit 20 that is installed outdoors, and an indoor unit 10 that is connected to the outdoor unit 20 by a refrigerant pipe 19 and is disposed indoors to cool indoor air. .

The outdoor unit 20 has an exterior, an outdoor casing 21 having a penetrating portion 21a on a plate surface, a compressor 22 provided in the outdoor casing 21 to compress a refrigerant, and an agent for condensing the compressed refrigerant. The first heat exchanger 23 and the cooling fan (not shown) which cool the high heat which generate | occur | produces in the compressor 22 and the 1st heat exchanger 23 are provided.

The indoor unit 10 has an external casing 11 having a predetermined device component mounted therein and an open front surface thereof, and a front cover 12 coupled to the front surface of the outer casing 11.

An inlet 13 for sucking air in the room is formed in the lower region of the front cover 12, and an outlet 14 for discharging heat exchanged cold air in the upper region of the front cover 12 opposite to the inlet 13. ) Is formed.

An operation panel 15 is provided between the suction port 13 and the discharge port 14 to operate and stop the air conditioner, and to control the strength and blowing direction of the heat exchanged air and the operation of the discharge port shutter (not shown). .

In the outer casing 11 of the indoor unit 10, as shown in FIG. 2, a second heat exchanger 16 is provided for contacting and exchanging heat with the sucked air.

The second heat exchanger 16 is inclined obliquely to increase the contact area with air.

Although not shown in the upper portion of the second heat exchanger 16, a blower is provided to guide the air sucked into the outer casing 11 through the inlet 13 and heat-exchanged by the second heat exchanger 16 to the upper side. have.

At this time, the blower is employed as a transverse fan rather than an axial flow type that is employed as a normal fan, and is mounted by a predetermined fan casing.

Thus, if the hot air in the room is introduced into the outer casing 11 through the inlet 13 during the operation of the compressor 22, the introduced air is transferred to the second heat exchanger 16 to exchange heat, The cold air is discharged back into the room through the discharge port 14 so that the temperature of the room can be lowered.

In the case of such an air conditioner, since the single compressor 22 is driven on and off, the compressor 22 is easily burned out and the compressor 22 repeatedly turns on and off. As a result, power consumption increases and heat exchange efficiency falls.

Therefore, in addition to this type of air conditioner, a multi-compressor (not shown) using two or more compressors is employed, while controlling the multi-compressor appropriately to suppress the hunting shape that may appear in the air conditioner and reduce the price. The technique which is intended to lead to the effect of the synergy and the effect of heat exchange efficiency is disclosed in Korean Patent Application No. 2001-15698 (filed March 26, 2001).

The disclosed technology measures the operating time of the multi-compressor to determine that the longer the operating time of the compressor, the greater the cooling load in the room, and to operate in combination according to the capacity of the multi-compressor according to the determined cooling load.

However, in the conventional multi-compressor control method for an air conditioner, since it simply depends on the operating time of the multi-compressor in determining the indoor load, the multi-compressor is repeatedly turned on and off. As the multi-compressor is variably controlled compared to the set time, when the outdoor temperature change is severe (when the cooling load is severe), there is a possibility that the load fluctuation of the multi-compressor becomes large overall, and the power consumption of the multi-compressor is increased. Not only can not be reduced relatively, but also has the disadvantage that can not operate the air conditioner efficiently.

The present invention has been made to solve the above problems, an object of the present invention, the simultaneous operation, the alternating operation and the single operation is selected based on the tendency according to the time difference when the multi-compressor is operated, the outdoor temperature change is severe In this case, there is no fear that the load fluctuation of the multi-compressor becomes large, and it is possible to provide a method of controlling a multi-compressor for an air conditioner, which can relatively reduce power consumption and efficiently operate the air conditioner.

The present invention for achieving the above object comprises the steps of determining the initial starting state and the indoor load of the multi-compressor according to the mutual relationship between the outdoor temperature and the predetermined reference temperature section; Simultaneously operating the multi-compressors based on the determined indoor load; It is achieved by providing a multi-compressor control method for an air conditioner comprising the step of switching the multi-compressor in the order of alternating operation and single operation based on the tendency according to the time difference when the multi-compressor is simultaneously operated.

Here, in the simultaneous operation of the multi-compressor, when the tendency of the operation time difference shows a tendency to decrease based on a predetermined number of times, the multi-compressor is switched to the alternating operation stage; When the tendency of the operation time difference shows a constant or a tendency to increase based on a predetermined number of times, the multi-compressor is not switched to the alternating operation but is maintained in the simultaneous operation stage.

In the alternating operation stage of the multi-compressor, when the tendency of the operation time difference shows a tendency to decrease based on a predetermined number of times, switching to one of the multi-compressor single operation stages; When the tendency of the operation time difference shows a tendency or increases on the basis of a predetermined number of times, the multi-compressor is not switched to the single operation but is maintained in the alternating operation stage.

In the alternating operation or the single operation step of the multi-compressor, when the trend of the operation time difference shows a constant or a tendency to increase based on a predetermined number, the method may further include resetting to the simultaneous operation step of the multi-compressor.

In the single operation step of the multi-compressor, a compressor having a smaller capacity among the respective compressors may be operated alone.

In the determining of the initial starting state of the multi-compressor according to the relationship between the outdoor temperature and the predetermined reference temperature section, when the outdoor temperature exceeds a preset maximum temperature, the multi-compressor is simultaneously operated and the outdoor temperature is When the temperature is lower than the preset minimum temperature, the operation of the multi-compressor is stopped.

In the step of determining the indoor load because the outdoor temperature is within a predetermined reference temperature section, the operation of the multi-compressor is controlled according to the case where the difference between the indoor temperature and the desired temperature is greater than or equal to or less than a predetermined reference temperature value. do.

When the difference between the room temperature and the desired temperature is above or below a predetermined reference temperature value, the multi-compressor is simultaneously operated until the room temperature reaches a temperature lower than the desired temperature by -α ° C., and the room temperature is Stopping the simultaneous operation of the multi-compressor when the temperature reaches a temperature lower than the desired temperature by? If the stored simultaneous operation time of the multi-compressor is more than a predetermined reference time is switched to the rated load operation step, if less than the predetermined reference time is switched to the low load operation step.

After the rated operation step, if the difference between the stored previous operation time and the current operation time occurs more than a predetermined reference time, the multi-compressor is switched to the alternating operation step, or reset to the initial step. .

In the alternating operation step of the multi-compressor, if a phenomenon in which the difference between the previous operation time and the current operation time stored by the alternating operation occurs more than a predetermined reference time continuously or more than a predetermined number of times, the single operation step of any of the multi-compressors If not, it is reset to the initial stage.

After the low load operation step, if the difference between the stored previous operation time and the current operation time occurs more than a predetermined reference time, the multi-compressor is switched to the alternate operation step. Otherwise, the initial operation step is reset. do.

The number of times of continuously determining a phenomenon in which the difference between the previous operation time and the current operation time stored in the rated load operation step is longer than a predetermined reference time may be set to be greater than the number determined in the low load operation step.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings, and the same reference numerals will be given to the same components as those of FIGS. 1 and 2 described above.

3 is a view schematically showing a refrigerating cycle for an air conditioner according to the present invention, showing a state in which the first compressor 22a and the second compressor 22b are disclosed.

For reference, in the above description of FIG. 2, reference numeral 22 is merely referred to as a compressor, but in the description of the present embodiment, it will be described as a first compressor 22a.

As shown in FIG. 3, the air conditioner according to the present invention is connected to the outdoor unit 20 by an outdoor unit 20 installed outdoors and a refrigerant pipe 19 and is disposed indoors as in the related art. It consists of an indoor unit 10 for cooling.

In the outdoor unit 20, multi-type first and second compressors 22a and 22b for compressing a refrigerant are provided, and the compressed refrigerant is condensed around the first and second compressors 22a and 22b. The first heat exchanger 23 is mounted.

As in the present invention, when the multi-type first and second compressors 22a and 22b are present, the first and second compressors 22a and 22b may employ the same capacities or different capacities. In the following description, it is assumed that the capacity of the second compressor 22b is smaller than that of the first compressor 22a.

The indoor unit 10 is provided with a second heat exchanger 16 which is inclined obliquely to increase the contact area with the sucked air and heat exchanges with the sucked air.

At this time, the second heat exchanger 16, the first heat exchanger 23, and the first and second compressors 22a and 22b are connected to each other to form a refrigeration cycle.

In addition, at the inlet side of the first and second compressors 22a and 22b, the liquid refrigerant is filtered out of the refrigerant flowing into the compressor, and then temporarily stored and regasified to filter the impurities contained in the refrigerant. An accumulator 24 is provided, check valves 25a and 25b are provided on the outlet sides of the first and the decompressors 22a and 22b, respectively, and an outlet side of the first heat exchanger 23 is provided. Expansion valve 17 is provided.

As described above, in a refrigeration system having a plurality of compressors, the multi-compressor control method for an air conditioner according to the present invention is characterized in that the first and second compressors 22a and 22b largely depend on the relationship between the outdoor temperature and the predetermined reference temperature section. Determining an initial starting state and an indoor load of the engine; and simultaneously operating the first and second compressors 22a and 22b based on the determined indoor load, and the first and second compressors 22a and 22b. And switching the first and second compressors 22a and 22b in the order of alternating operation and single operation based on the tendency according to the time difference being simultaneously operated.

On the other hand, Figure 4 shows the room temperature ultimately by the operation of the first and second compressors 22a, 22b, whether the first and second compressors (22a, 22b) at any stage of simultaneous, alternating and single operation. Is a schematic graph of reaching the desired temperature "ST", where T _{1 (A + B)} and T _{1 (A → B)} to T _{1 (B)} are the first and second compressors 22a, respectively. , 22b) shows the operating time according to the simultaneous operation, the alternating operation and the single operation.

When referring to Figure 4, for example, the first and second compressors (22a, 22b) is at least 10 minutes, simultaneously driving the operation time _{T 1 (A + B),} T 2 (A + B) is 8 If the minutes, T _{3 (A + B)} is 6 minutes, and T _{4 (A + B)} is 4 minutes, the respective driving time difference is constantly reduced at two-minute intervals based on three times.

In this case, if the first and second compressors 22a and 22b were in the simultaneous operation step, the operation is switched to the alternating operation step.

In addition, if the tendency of the operation time difference of the compressor to decrease as described above occurs in the alternating operation stage, it may be switched to the single operation stage of any one of the first and second compressors 22a and 22b.

Further, for example, the operation time is T _{1 (A + B)} 12 minutes, T _{2 (A + B)} 9 minutes, T _{3 (A + B)} 7 minutes, T _{4 (A + B)} If 6 minutes, each driving time difference also tends to decrease to 3 minutes, 2 minutes, 1 minute based on three times.

In this case, too, if the first and second compressors 22a and 22b were in the simultaneous operation stage, they are switched to the alternating operation stage, and if they were in the alternating operation stage, either one of the first and second compressors 22a and 22b. Can be switched to the single run step.

However, for example, the operation time is T _{1 (A + B)} 12 minutes, T _{2 (A + B)} 9 minutes, T _{3 (A + B)} 8 minutes, T _{4 (A + B)} If 12 minutes, the driving time difference decreases to three minutes and one minute based on three times and then increases to four minutes.

In this case, if the first and second compressors 22a and 22b were in the simultaneous operation stage, they could not be switched to the alternate operation stage and remain in the simultaneous operation stage. Reset by simultaneous operation of.

Of course, at this time, the present invention proposes to determine the trend of the difference of each operation time in the alternating operation step by reducing the two times, unlike three times of simultaneous operation as one embodiment.

As described above, the first and second compressors 22a and 22b cannot be switched to the next stage and continue to maintain the stages. The tendency of the first and second compressors 22a and 22b according to the operation time difference of the first and second compressors 22a and 22b is a predetermined number of times. The same applies when showing a tendency to increase on the basis of three or two times).

Then, T _{1 (A + B)} is reduced to 12 minutes, T _{2 (A + B)} is reduced to 9 minutes, T _{3 (A + B)} is reduced to 8 minutes as described above, and T _{4 (A + B)} is reduced to 12 minutes. In the case of increasing to minutes, the operation condition is selected by recognizing the trend according to the operation time difference of the compressor from T _{1 (A + B)} again a predetermined number of times.

At this time, when determining the tendency according to the operation time difference of the first and second compressors (22a, 22b), the reference number may be predetermined depending on the situation, in the present embodiment is to be switched from the simultaneous operation to the alternating operation The standard number of times is three times, and the standard number of times when switching from alternating operation to single operation is two times.

In the single operation, only the second compressor 22b having a small capacity is set to operate alone.

Then, the multi-compressor control method according to the present invention will be described again sequentially with reference to FIG.

In FIG. 5, T _O denotes an outdoor temperature, T ₁ denotes a set minimum temperature, T ₂ denotes a set maximum temperature, and COMP 1,2 denotes first and second compressors 22a and 22b, respectively.

First, when the cooling operation is started (S1), the outdoor temperature is judged (S2) to determine whether the outdoor temperature is within a predetermined reference temperature section (T ₁ to T ₂ ; Determine (S3).

If the outdoor temperature is less than or equal to a predetermined minimum temperature T ₁ (eg, T ₁ is 10 ° C.) (S5), the first and second compressors 22a and 22b may not operate (S6).

However, if the outdoor temperature exceeds a preset maximum temperature T ₂ (for example, T ₂ is 35 ° C.) (S7), the first and second compressors 22a and 22b are operated (S8). When the room temperature reaches " desirable temperature-alpha deg. C " (meaning a temperature which is alpha deg. C lower than the desired temperature), the first and second compressors 22a and 22b are reset again after being turned off.

In addition, the outdoor temperature is determined (S2), when the outdoor temperature (T ₀ ) is within a predetermined reference temperature section (T ₁ to T ₂ ; for example, a section of more than 10 ℃ 35 ℃), the initial To determine the starting and indoor loads (S4), when the difference between the room temperature and the desired temperature is equal to or greater than a predetermined reference temperature value (ΔT; for example, ΔT is 2 ° C) (S9) and the predetermined reference temperature value ( ΔT; for example, ΔT is divided into a case of less than 2 ° C. (S19).

At this time, in the present invention, when the difference between the room temperature and the desired temperature is a predetermined reference temperature value (ΔT; for example, ΔT is 2 ° C.) or more (S9), it becomes a condition for determining the rated load operation step. When the difference between the room temperature and the desired temperature is less than the predetermined reference temperature value? T (for example,? T is 2 ° C) (S19), the condition for determining the low load operation step is set.

First, when the difference between the room temperature and the desired temperature is equal to or greater than a predetermined reference temperature value? T (for example,? T is 2 ° C) (S9), the room temperature reaches "desired temperature -α ° C". Until the first and the second compressor (22a, 22b) are both operating at the same time (S10).

For reference, in the step S10, the outdoor air volume may be driven by a strong wind and the indoor air volume by a set wind.

When the indoor temperature reaches "desired temperature -α ° C", the first and second compressors 22a and 22b are stopped and the first operating time of the first and second compressors 22a and 22b is stored (S11). ).

In particular, at this time, when the difference between the indoor temperature and the desired temperature is a predetermined reference temperature value (ΔT; for example, ΔT is 2 ° C.) or more (S9), and the predetermined reference temperature value (ΔT; △ T is 2 ℃) (first operation time with a predetermined reference time (M ₁ of the first and second compressors (22a, 22b) is stored the in a state that on the basis of S19) less than; for example, M ₁ is 15 minutes) or more (S12), and enters the rated load operation (S13), otherwise it enters the low load operation step (S22), which will be described later.

In this rated load operation step, when the room temperature reaches "desired temperature + α ℃ (which means α ℃ higher than the desired temperature)", both the first and second compressors 22a, 22b are operated. The outdoor air volume is strong wind and the indoor air volume is driven by the set wind.

However, at this time, the first and second compressors 22a and 22b are cases where a predetermined time (for example, three minutes) has elapsed after being turned off.

Then, when the room temperature reaches "desired temperature -α ℃", the first and second compressors 22a and 22b are both stopped and the operating time of the first and second compressors 22a and 22b is stored.

In the process of repeating steps S10, S11, S12, and S13, a phenomenon in which a difference between the previous operation time and the current operation time occurs more than a predetermined reference time ΔM (for example, ΔM is 2 minutes) is continuously prescribed. Operate until a number of times N ₁ occurs (e.g., N ₁ is three times).

If three times occur (S14), it is switched to the alternate operation step of the first and second compressors (22a, 22b) (S15).

In the alternating operation step, when the indoor temperature reaches "desired temperature + alpha ℃", both the first and second compressors 22a and 22b are operated, but the outdoor air volume is driven by the strong wind, the indoor air volume is set by the set wind.

During the operation, when the room temperature reaches the desired temperature, the operation of the first compressor 22a is stopped.

At this time, the outdoor air volume is weak air, the indoor air volume is driven by the set wind.

Of course, in this case, the second compressor 22b continues to operate under the condition that the indoor temperature is lower than the desired temperature. When the indoor temperature reaches "desired temperature -α ° C" in this way, the second compressor ( 22b) is stopped.

Then, the operation time of the second compressor 22b (the time from when the first compressor 22a is stopped until the second compressor 22b is stopped; T _{n (A → B)} ) is stored.

This alternating operation step is repeated, but a phenomenon in which the difference between the previous operation time and the current operation time occurs more than a predetermined reference time ΔM (for example, ΔM is 2 minutes) is continuously performed a predetermined number of times (N ₂ ; For example, when N ₂ occurs twice, it is switched to the single operation step of the second compressor 22b (S17).

However, after the alternating operation step, a phenomenon in which the difference between the previous operation time and the current operation time occurs more than a predetermined reference time ΔM (for example, ΔM is 2 minutes) is continuously performed for a predetermined number of times N ₂ ; For example, when N ₂ does not occur twice, a predetermined number of times (N ₃ ; for example, N ₃ is 10 times) is repeated, or the operation time of the second compressor 22b is a predetermined time (M ₂ ; For example, when M ₂ occurs more than 6 minutes, a predetermined number of times (N ₂ ; for example, N ₂ is 2 times) continuously or the sum of the driving times is a predetermined time (M ₃ ; M ₃ is 30 minutes) or more (S18), and moves back to step S2 to determine the outdoor temperature.

In the single operation step, when the room temperature reaches "desired temperature + alpha ℃", the second compressor 22b is operated.

 At this time, the outdoor air volume is weak air, the indoor air volume is driven by the set wind.

During the operation, when the room temperature reaches "desired temperature-? Deg. C", the operation of the second compressor 22b is stopped.

At this time, the second compressor 22b may be restarted after a predetermined time (for example, three minutes) has elapsed after the stop.

If the integration operation time of the second compressor 22b exceeds a predetermined time M ₃ (for example, M ₃ is 30 minutes) (S24), the flow returns to step S2 of determining the outdoor temperature. .

On the other hand, if the difference between the room temperature and the desired temperature is less than the predetermined reference temperature value ΔT (for example, ΔT is 2 ° C), the process returns to the step S4 of initial starting and indoor load again (S19). As described, both the first and second compressors 22a and 22b are operated until the room temperature reaches "desired temperature -α ° C", and when the room temperature reaches "desired temperature -α ° C", the first and second compressors are operated. The second compressors 22a and 22b are both stopped and the first operation time is stored. If the first operation time is more than a predetermined reference time M ₁ (for example, M ₁ is 15 minutes), the rated load operation step is performed. It moves (S20).

If the first operation time of the first and second compressors 22a and 22b is less than the predetermined reference time M ₁ (for example, M ₁ is 15 minutes) (S21), the apparatus enters the low load operation ( S22).

In the low load operation step, when the indoor temperature reaches "desired temperature + alpha ℃", both the first and second compressors 22a and 22b are operated, but the outdoor air volume is driven by the strong wind, the indoor air volume is set by the set wind.

In this case, the first and second compressors 22a and 22b have passed after a predetermined time (for example, three minutes) has elapsed.

When the indoor temperature reaches the "desired temperature -α ℃", the operating time at this time is stored while stopping the first and second compressors (22a, 22b).

After the low load operation step, a phenomenon in which a difference between the previous operation time and the current operation time occurs more than a predetermined reference time ΔM (for example, ΔM is 2 minutes) occurs a predetermined number of times (N ₂ ; For example, when N ₂ occurs twice) (S23), the operation is switched to the alternating operation steps of the first and second compressors 22a and 22b described above, and the steps S20, S21 and S22 are repeated.

As described above, according to the present invention, the power consumption required by the simultaneous operation, the alternating operation and the single operation are relatively reduced based on the tendency of the time difference between the first and second compressors 22a and 22b to be operated. Compared with the prior art, the air conditioner can be operated efficiently.

In the embodiment of the present invention, the difference in subtracting the operation time difference of the multi-compressor from the previous operation time to the next operation time is more than two minutes, and the multiplication is performed depending on whether the number of times is repeated three times. It shows that the operation condition of the compressor is controlled.

However, it is apparent that the present invention is not limited to the above preferred embodiment.

Meanwhile, in the above-described embodiment, the multi-compressor is described as the first and second compressors 22a and 22b. However, even if an air conditioner in which three or more compressors can be employed, the idea of the present invention can be sufficiently applied. .

In the above-described embodiment, the air conditioner in which the indoor unit and the outdoor unit are separately separated from the stand type air conditioner has been described as an example.

However, the idea of the present invention may be sufficiently applied to a multi-air conditioner system in which a separate or integrated indoor unit (not shown) is provided in several rooms such as an office and drives them into one outdoor unit 20 having a plurality of compressors.

As described above, according to the present invention, the simultaneous operation, the alternating operation and the single operation are selected based on the tendency according to the time difference in which the multi-compressor is operated, so that the load fluctuation range of the multi-compressor is not large even when the outdoor temperature change is severe. It is possible to relatively reduce the power consumption, and to operate the air conditioner efficiently.

1 is a perspective view of a conventional air conditioner,

2 is a view schematically showing a refrigeration cycle employed in the air conditioner shown in FIG.

3 is a view schematically showing a refrigeration cycle for an air conditioner according to the present invention,

Figure 4 is a simplified graph for explaining a multi-compressor control method for an air conditioner according to the present invention,

5 is a control algorithm of a multi-compressor according to the present invention.

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

10: indoor unit 11: outer casing

12: front cover 13: inlet

14 discharge port 15 operation panel

16 second heat exchanger 17 expansion valve

20: outdoor unit 22a, 22b: first and second compressor

23: first heat exchanger 24: accumulator

25a, 25b: check valve

Claims (12)

Determining an initial starting state and an indoor load of the multi-compressor according to the mutual relationship between the outdoor temperature and the predetermined reference temperature section; Simultaneously operating the multi-compressors based on the determined indoor load; And switching the multi-compressor in the order of alternating operation and single operation based on the tendency according to the time difference when the multi-compressor is simultaneously operated. The method of claim 1, In the simultaneous operation of the multi-compressor, when the tendency of the operation time difference shows a tendency to decrease based on a predetermined number of times, converting the multi-compressor to the alternate operation step; The multi-compressor control method for an air conditioner, wherein the multi-compressor is not switched to the alternating operation and is maintained in the simultaneous operation step when the tendency of the operation time difference is constant or increases based on a predetermined number of times. The method of claim 2, In the alternating operation stage of the multi-compressor, when the tendency of the operation time difference shows a tendency to decrease based on a predetermined number of times, switching to one of the multi-compressor single operation stages; The multi-compressor control method for an air conditioner, characterized in that the multi-compressor is not switched to the single operation but is maintained in the alternating operation step when the tendency of the operation time difference is constant or increases based on a predetermined number of times. The method according to claim 2 or 3, In the alternating operation or the single operation step of the multi-compressor, if the trend of the operation time difference shows a tendency to increase or increase based on a predetermined number of times, further comprising the step of resetting to the simultaneous operation step of the multi-compressor Multi compressor control method for an air conditioner. The method of claim 1, In the single operation step of the multi-compressor, a compressor having a smaller capacity among each of the compressors is operated independently. The method of claim 1, In the determining of the initial starting state of the multi-compressor according to the mutual relationship between the outdoor temperature and the predetermined reference temperature section, when the outdoor temperature exceeds the set maximum temperature, the multi-compressor is simultaneously operated and the outdoor temperature is set. The control method of the multi-compressor for an air conditioner, characterized in that for stopping the operation of the multi-compressor below the minimum temperature. The method of claim 1, In the step of determining the indoor load because the outdoor temperature is within a predetermined reference temperature section, the operation of the multi-compressor is controlled according to the case where the difference between the indoor temperature and the desired temperature is greater than or equal to or less than a predetermined reference temperature value. But; The control method of the multi-compressor for an air conditioner if the reference temperature value or more is controlled under the conditions for determining the predetermined rated load operation step, and if the reference temperature value is less than the preset low load operation step. The method of claim 7, wherein When the difference between the room temperature and the desired temperature is above or below a predetermined reference temperature value, the multi-compressor is simultaneously operated until the room temperature reaches a temperature lower than the desired temperature by -α ° C., and the room temperature is Stopping the simultaneous operation of the multi-compressor when the temperature reaches a temperature lower than the desired temperature by? And if the stored simultaneous operation time of the multi-compressor is greater than or equal to a predetermined reference time, is switched to the rated load operation step, and if it is less than the predetermined reference time, it is switched to a low load operation step. The method of claim 8, After the rated operation step, if the difference between the stored previous operation time and the current operation time occurs more than a predetermined reference time, the multi-compressor is switched to the alternate operation step. Multi compressor control method for an air conditioner, characterized in that. The method of claim 9, In the alternating operation step of the multi-compressor, if a phenomenon in which the difference between the previous operation time and the current operation time stored by the alternating operation occurs more than a predetermined reference time continuously or more than a predetermined number of times, the single operation step of any of the multi-compressors And, if not, reset to the initial stage. The method according to any one of claims 7 to 11, After the low load operation step, if the difference between the stored previous operation time and the current operation time occurs more than a predetermined reference time, the multi-compressor is switched to the alternate operation step. Otherwise, the initial operation step is reset. Multi compressor control method for an air conditioner, characterized in that the. The method of claim 11, Air conditioning, characterized in that the number of times of continuously judging the phenomenon that the difference between the previous operating time and the current operating time stored in the rated load operation step more than a predetermined reference time occurs more than the number determined in the low load operation step Multi compressor control method.