KR102025745B1 - Air conditioner and thereof control process - Google Patents

Abstract

The present invention relates to an air conditioner and a control method of the air conditioner, and more particularly, to control the compressor operation frequency to reduce the vibration of the compressor, the air conditioner and air to equalize the amount of oil contained in the compressor It relates to a control method of the harmonic.
An air conditioner according to an embodiment of the present invention includes a dual inverter compressor including a first inverter compressor and a second inverter compressor; An operation region determination unit configured to determine in which operation region the dual inverter compressor operates in a high frequency operation region and a low frequency operation region;
An offset setting unit which generates an operating frequency offset of the dual inverter compressor based on the operating area; And a controller configured to generate operating frequencies of the first and second inverter compressors based on the operating frequency offset, and generate a control signal for driving the dual inverter compressor based on the operating frequencies of the first and second inverter compressors. It includes.
In addition, the air conditioner according to another embodiment of the present invention compresses and discharges the refrigerant containing the oil, at least one inverter compressor that can change the operating frequency; At least one oil separator which separates oil mixed in the refrigerant discharged from the at least one inverter compressor and returns the oil to the at least one inverter compressor; Allocating operating frequencies of the at least one inverter compressor such that a difference value between the maximum operating frequency and the minimum operating frequency among the operating frequencies of the at least one inverter compressor is equal to or less than a second reference frequency based on a driving load required by an indoor unit. Frequency allocation unit; And a controller configured to generate a control signal for driving the at least one inverter compressor based on the assigned operating frequencies to equalize the amount of oil in the at least one inverter compressor.
According to the air conditioner according to an embodiment of the present invention, the offset of the low frequency operating region and the high frequency operating region of the compressor is set differently, thereby reducing the vibration transmission of the compressor and increasing the cycle reliability.
In addition, according to the air conditioner according to another embodiment of the present invention, it is possible to enable even oil distribution without structurally large changes.

Description

Air conditioner and air conditioner control method {AIR CONDITIONER AND THEREOF CONTROL PROCESS}

The present invention relates to an air conditioner and a control method of the air conditioner, and more particularly, to control the compressor operation frequency to reduce the vibration of the compressor, the air conditioner and air to equalize the amount of oil contained in the compressor It relates to a control method of the harmonic.

In general, an air conditioner includes a plurality of outdoor units and a plurality of indoor units.

The outdoor unit is provided with a compressor, a four-way valve, an outdoor heat exchanger, and an expansion valve, and the indoor unit is provided with an indoor heat exchanger.

The compressor, the four-way valve, the outdoor heat exchanger, the expansion valve, and the indoor heat exchanger are configured to be connected by the refrigerant pipe to form a cooling and heating cycle.

The compressor may include an inverter compressor having a variable capacity and a constant speed compressor having a variable capacity.

When two inverter compressors are operated at the same operating frequency, twice the amplitude occurs when the compressor is operated with one compressor, and the vibration energy applied for a predetermined time increases because it is operated at one frequency.

In addition, when two inverter compressors are operated at the same operating frequency, if the eigenvalues of the pipes connected to the compressor coincide with the operating frequency, resonance may occur in the pipes and the pipes may be damaged.

On the other hand, in recent years, multi-system air conditioners have become increasingly high in capacity, long piping, increasing the number of indoor units connected, and expanding the installation of indoor and outdoor periods, thereby increasing the importance of supplying lubricating oil to compressors. do.

Therefore, when two or more compressors are installed in a multi-system air conditioner in which one or more outdoor units and one or more indoor units are connected, proper oil amount distribution between each compressor is an essential technique to prevent mechanical damage of the compressor.

Among conventional oil amount distribution techniques between compressors, there is a method of redistributing oil amount by artificial operation.

If there is a pipe to move the oil between the compressor, and if the compressor on / off control the state of the compressor (shell) (shell) itself is different from each other and the oil is moved between the compressor by the pressure difference.

In this oil redistribution operation, the oil level is directly detected or periodically entered at regular operation times.

Among these, the method of directly detecting the oil amount has a problem of missing the proper oil amount redistribution timing due to misdetection.

In addition, the periodic entry at regular operation time enters the control even in the situation where the oil quantity redistribution is not necessary, and causes the transient state of the pressure and temperature of the system by artificial compressor on / off or valve open / close, thereby heating and cooling There is a problem that causes a temporary decrease in performance.

An embodiment of the present invention provides an air conditioner and a control method of the air conditioner to reduce the vibration energy applied to the pipe by varying the operating frequency of the two compressors.

Another embodiment of the present invention provides an air conditioner that controls the operating frequency of a plurality of compressors to adjust the oil amount of the plurality of compressors to an equal level.

An air conditioner according to an embodiment of the present invention includes a dual inverter compressor including a first inverter compressor and a second inverter compressor; An operation region determination unit configured to determine in which operation region the dual inverter compressor operates in a high frequency operation region and a low frequency operation region;

An offset setting unit which generates an operating frequency offset of the dual inverter compressor based on the operating area; And a controller configured to generate operating frequencies of the first and second inverter compressors based on the operating frequency offset, and generate a control signal for driving the dual inverter compressor based on the operating frequencies of the first and second inverter compressors. It includes.

The driving region determination unit may include calculating an average operating frequency of the dual inverter compressor, and determining the driving region based on the average operating frequency.

The offset setting unit may include determining the driving frequency offset as a first predetermined frequency when the dual inverter compressor operates in the high frequency driving region.

The offset setting unit may include determining the driving frequency offset as a second predetermined frequency when the dual inverter compressor operates in the low frequency driving region.

The control unit may include a difference between an operating frequency of the first inverter compressor and an operating frequency of the second inverter compressor to be the operating frequency offset.

In a control method of an air conditioner according to an embodiment of the present invention, a control method of an air conditioner including a dual inverter compressor including a first inverter compressor and a second inverter compressor, wherein the dual inverter compressor is a high frequency operating region. And in which driving region the low frequency driving region is operated; Generate an operating frequency offset of the dual inverter compressor based on the operating region; Generate operating frequencies of the first and second inverter compressors based on the operating frequency offset; Driving the dual inverter compressor based on operating frequencies of the first and second inverter compressors.

The determining of the operating area may include calculating an average operating frequency of the dual inverter compressor and determining the operating area based on the average operating frequency.

The generating of the driving frequency offset may include determining the driving frequency offset as a first predetermined frequency when the dual inverter compressor operates in the high frequency driving region.

The generating of the operating frequency offset may include determining the operating frequency offset as a second predetermined frequency when the dual inverter compressor operates in the low frequency driving region.

In addition, generating operating frequencies of the first and second inverter compressors includes causing a difference between the operating frequency of the first inverter compressor and the operating frequency of the second inverter compressor to be the operating frequency offset.

According to another embodiment of the present invention, an air conditioner includes: at least one inverter compressor configured to compress and discharge a refrigerant containing oil and change an operating frequency of the refrigerant; At least one oil separator which separates oil mixed in the refrigerant discharged from the at least one inverter compressor and returns the oil to the at least one inverter compressor; Allocating operating frequencies of the at least one inverter compressor such that a difference value between the maximum operating frequency and the minimum operating frequency among the operating frequencies of the at least one inverter compressor is equal to or less than a second reference frequency based on a driving load required by an indoor unit. Frequency allocation unit; And a controller configured to generate a control signal for driving the at least one inverter compressor based on the assigned operating frequencies to equalize the amount of oil in the at least one inverter compressor.

The frequency allocator may include allocating the operating frequencies such that the amount of oil discharged from the at least one inverter compressor is the same.

The apparatus may further include a frequency variation detector configured to detect whether the difference between the maximum driving frequency and the minimum driving frequency is greater than the second reference frequency, and wherein the frequency allocation unit is configured to make the difference greater than the second reference frequency. And reassigning operating frequencies of the at least one inverter compressor when the first reference time elapses from the time point.

In addition, reassigning operating frequencies of the at least one inverter compressor may increase or decrease the operating frequencies of the at least one inverter compressor or stop operation of the at least one inverter compressor, thereby reducing the maximum operating frequency and the minimum operating frequency. Assigning operating frequencies of the at least one inverter compressor such that the difference is less than or equal to the second reference frequency.

According to another embodiment of the present invention, an air conditioner includes: at least one inverter compressor configured to compress and discharge a refrigerant containing oil and change an operating frequency of the refrigerant; At least one constant speed compressor that compresses and discharges a refrigerant containing oil and has a constant operating frequency; At least one oil separator which separates oil mixed in the refrigerant discharged from the at least one inverter compressor and the at least one constant speed compressor and returns the oil to the at least one inverter compressor and the at least one constant speed compressor; The at least one inverter such that a difference between the maximum operating frequency and the minimum operating frequency among the operating frequencies of the at least one inverter compressor and the at least one constant speed compressor is equal to or less than a third reference frequency based on a driving load required by an indoor unit; A frequency allocator for allocating operating frequencies of the compressor; And generating a control signal for driving the at least one inverter compressor and the at least one constant speed compressor based on the assigned operating frequencies to equalize the amount of oil in the at least one inverter compressor and the at least one constant speed compressor. It includes a control unit.

The frequency allocator may include assigning operating frequencies of the at least one inverter compressor such that the amount of oil discharged from the at least one inverter compressor is equal to the amount of oil discharged from the at least one constant speed compressor.

The apparatus may further include a frequency detector configured to detect whether a difference between the maximum driving frequency and the minimum driving frequency is greater than the third reference frequency, and wherein the driving frequency allocator may cause the difference to be greater than the third reference frequency. And reassigning operating frequencies of the at least one inverter compressor when the first reference time elapses from the time point.

Reassigning operating frequencies of the at least one inverter compressor increases or decreases the operating frequencies of the at least one inverter compressor or stops the operation of the at least one inverter compressor, such that the difference between the maximum operating frequency and the minimum operating frequency Assigning operating frequencies of the at least one inverter compressor to be less than or equal to the third reference frequency.

In addition, reassigning operating frequencies of the at least one inverter compressor may increase or decrease the operating frequencies of the at least one inverter compressor or stop the operation of at least one inverter compressor, thereby resetting the operating frequencies of the at least one inverter compressor. Assigning operating frequencies of the at least one inverter compressor such that the difference value of the minimum operating frequency is greater than a third reference frequency.

According to the air conditioner according to an embodiment of the present invention, the offset of the low frequency operating region and the high frequency operating region of the compressor is set differently, thereby reducing the vibration transmission of the compressor and increasing the cycle reliability.

According to the air conditioner according to another embodiment of the present invention, by minimizing the separate artificial compressor on / off of the multi-system air conditioner or the open / close of the valve to minimize the temporary deterioration of the cooling and heating performance due to the oil operation, the compressor This can prevent mechanical damage due to poor lubrication.

In addition, according to the air conditioner according to another embodiment of the present invention, it is possible to enable even oil distribution without structurally large changes.

1 is a view showing the configuration of an air conditioner according to an embodiment of the present invention.
2 is a control block diagram of an air conditioner according to an embodiment of the present invention.
3 is a diagram showing a vibration waveform obtained by combining an operating frequency of a first compressor and an operating frequency of a second compressor of an air conditioner according to an exemplary embodiment of the present invention.
4 is a flowchart illustrating a control method of an air conditioner according to an embodiment of the present invention.
5 is a view showing a pipe stress according to the offset degree of the air conditioner according to an embodiment of the present invention.
6 is a view showing a control block diagram of an air conditioner according to another embodiment of the present invention.
7a and 7b are views showing the oil flow amount according to the model of the compressor according to another embodiment of the present invention.
8 is a flowchart illustrating a control method of an air conditioner according to another embodiment of the present invention.

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

1 is a view showing the configuration of an air conditioner according to an embodiment of the present invention.

As shown in FIG. 1, the air conditioner includes an outdoor unit 1 and an indoor unit 2.

The outdoor unit 1 includes a dual compressor 10 sequentially connected to a refrigerant pipe to form a closed circuit, a four-way valve 3 for switching cooling and heating, an outdoor heat exchanger 4, an expansion valve 5, an accumulator A, and Oil separators 12, 17 may be included.

The indoor unit 2 may include an indoor heat exchanger 6.

The air conditioner may be configured as a multi air conditioner in which a plurality of indoor heat exchangers 6 are provided. When the air conditioner is configured as a multi air conditioner, the electric expansion valves 31, 32, and 33 may be provided for each indoor heat exchanger 6.

The dual compressor 10 includes a first compressor 11 and a second compressor 13, and although two compressors are illustrated in the drawing, two or more compressors may be provided.

Each compressor 11 and 16 compresses and discharges the sucked gas refrigerant | coolant, and various things, such as a rotary type or a piston type, can be used.

In addition, each of the compressors 11 and 16 may include a constant speed compressor or an inverter compressor.

Constant speed compressor has constant output by controlling rotation speed at 100% constant speed. The inverter compressor may change the driving capability by controlling the rotation speed of the motor in accordance with the frequency change.

The four-way valve 3 guides the high temperature and high pressure refrigerant discharged from the dual compressor 10 to the indoor unit 2 during the heating operation, and guides the low temperature low pressure refrigerant of the outdoor heat exchanger 4 to the accumulator A. have. At this time, the outdoor heat exchanger 4 may perform the function of an evaporator.

The evaporator can be superheated by evaporating the liquid refrigerant at a low pressure.

On the other hand, the four-way valve 3 guides the high temperature and high pressure refrigerant discharged from the dual compressor 10 to the outdoor heat exchanger 4 during the cooling operation, and accumulates the low temperature low pressure refrigerant of the indoor heat exchanger 6. Can be guided to. At this time, the outdoor heat exchanger 4 may perform the function of a condenser.

The condenser may condense the gas refrigerant discharged from the dual compressor 10 in a state of maintaining a high pressure, thereby making it a supercooled state.

The outdoor heat exchanger 4 is disposed between the four-way valve 3 and the expansion valve 5, and can perform heat exchange with the outdoor air.

The indoor heat exchanger 6 is disposed between the four-way valve 3 and the internal heat exchanger 20, and may perform heat exchange with the indoor air.

The expansion valve 5 is disposed between the outdoor heat exchanger 4 and the internal heat exchanger 20, and may include an electronic expansion valve (EEV) which can adjust the opening degree to adjust the flow rate of the refrigerant.

The accumulator (A) is disposed on the suction side of the dual compressor (10) and separates the unvaporized liquid refrigerant from the refrigerant flowing into the dual compressor (10) to prevent the liquid refrigerant from being discharged to the dual compressor (10). Damage to the compressor 10 can be prevented.

The oil separators 12 and 17 include a first oil separator 12 and a second oil separator 17 and are disposed on the discharge side of the dual compressor 10 and are in the vapor of the discharge refrigerant of the dual compressor 10. By separating the mixed oil and returning the mixed oil to the dual compressor 10, an oil film is formed on the surfaces of the outdoor heat exchanger 4 and the indoor heat exchanger 6 to prevent deterioration of the heat transfer effect. The lack of lubricating oil can be generated and the lubrication action can be prevented from being lowered.

The first oil separator 12 separates the oil contained in the refrigerant discharged from the first compressor 11, and connects the first oil return pipe connecting the first oil separator 12 and the seventh refrigerant pipe P7 ( The second compressor 16 may be returned to the second compressor 16 through the OL1) and the seventh refrigerant pipe P7.

The second oil separator 17 separates the oil contained in the refrigerant discharged from the second compressor 16 and connects the second oil return pipe connecting the second oil separator 17 and the eighth refrigerant pipe P8 ( Through the OL2) and the eighth refrigerant pipes P8, it may be returned to the first compressor 11.

In addition, although not shown in FIG. 1, the first oil separator 12 separates oil contained in the refrigerant discharged from the first compressor 11, and the first oil separator 12 and the sixth refrigerant pipe P6. The first compressor 11 and the second compressor 16 through the first oil return pipe (OL1), the sixth refrigerant pipe (P6), the seventh refrigerant pipe (P7), the eighth refrigerant pipe (P8) connecting the ) Can be returned.

In addition, although not shown in FIG. 1, the second oil separator 17 separates oil contained in the refrigerant discharged from the second compressor 16, and the second oil separator 17 and the sixth refrigerant pipe P6. The first compressor 11 and the second compressor 16 through the second oil return pipe (OL2), the sixth refrigerant pipe (P6), the seventh refrigerant pipe (P7), the eighth refrigerant pipe (P8) connecting the ) Can be returned.

The check valves 13 and 18 are disposed between the oil separators 12 and 17 and the four-way valve 3, and can prevent the refrigerant from flowing back.

During the heating operation of the air conditioner, the high temperature and high pressure refrigerant discharged from the dual compressor 10 is introduced into the indoor heat exchanger 6 operated by the condenser through the first refrigerant pipe P1 via the four-way valve 3.

The introduced high temperature high pressure refrigerant heats the indoor air outside the indoor heat exchanger 6 in the indoor heat exchanger 6 to warm the indoor air.

The refrigerant passing through the indoor heat exchanger (6) is moved through the second refrigerant pipe (P2) and the third refrigerant pipe (P3), and is expanded while passing through the expansion valve (5) provided in the third refrigerant pipe (P3). After the pressure is reduced, it is introduced into the outdoor heat exchanger (4), and recycled back to the dual compressor (10) through the fourth refrigerant pipe (P4) to form a heating cycle.

Since the cooling operation of the air conditioner has only the difference that the refrigerant flows in the opposite direction during the heating operation, the description of the general refrigerant flow will be omitted.

The air conditioner may inject superheated steam into the dual compressor 10 to improve the efficiency of the dual compressor 10 when the efficiency of the dual compressor 10 is lowered during the heating operation and the cooling operation.

In addition, in order to allow superheated steam to be injected into the dual compressor 10, the air conditioner includes an internal heat exchanger 20, an electric expansion valve 30, a superheated steam injection port 40, and a bypass valve 50. It may further include a superheated steam cutoff valve 60, and a muffler (70).

The internal heat exchanger 20 is disposed between the expansion valve 5 and the indoor heat exchanger 6, and may generate superheated steam through heat exchange.

The electric expansion valve 30 is provided in the first bypass pipe B1 provided so that the gas refrigerant passing through the internal heat exchanger 20 can enter the internal heat exchanger 20 again. The gas refrigerant passing through the) may be expanded and the gas refrigerant may be controlled to be re-entered into the internal heat exchanger 20 or may be prevented from entering.

The superheated steam injection port 40 may be provided in the superheated steam guide pipe P5 for guiding the superheated steam generated by the internal heat exchanger 20 to the dual compressor 10 to inject the superheated steam into the dual compressor 10. .

The bypass valve 50 may be provided in the second bypass pipe B2 bypassed from the superheated steam guide pipe P5 to control the superheated steam to be injected into the dual compressor 10 or to prevent the injection.

The superheated steam cutoff valve 60 may be provided in the superheated steam guide pipe P5 to control the superheated steam to be injected into the dual compressor 10 or to prevent the injection.

The muffler 70 is provided between the superheated steam shutoff valve 60 and the superheated steam injection port 40, and even when a unidirectional valve is used as the superheated steam shutoff valve 60, the muffler 70 receives the pulsation pressure transmitted from the dual compressor 10. Can be attenuated.

2 is a view showing a control block diagram of an air conditioner according to an embodiment of the present invention, Figure 3 is an operating frequency of the first compressor and the operation of the second compressor of the air conditioner according to an embodiment of the present invention A diagram illustrating vibration waveforms synthesized from frequencies.

As shown in FIG. 2, the air conditioner includes an operation region determiner 110, an offset setting unit 120, a controller 130, a first inverter compressor driver 142, a second inverter compressor driver 144, and Dual inverter compressors 11 and 16 may be included.

The operation region determination unit 110 may determine which operation region the dual inverter compressor 10 operates in the high frequency operation region and the low frequency operation region.

When the indoor unit 2 operates, the operating frequency of the dual inverter compressor 10 may be set to provide the cooling capability required by the indoor unit 2.

In this case, the operation region determination unit 110 may calculate an average operating frequency of the dual inverter compressor 10 and determine the operation region based on the average operating frequency.

If the average driving frequency is greater than or equal to a predetermined first reference frequency, the driving region determiner 110 may determine the driving region as the high frequency driving region.

Here, the reference frequency is a frequency used as a reference for distinguishing the high frequency driving region from the low frequency driving region, and a frequency region above the first reference frequency is called a high frequency operating region, and a frequency region below the first reference frequency is called a low frequency driving region.

For example, the reference frequency may comprise 50 Hz.

If the average driving frequency is less than the first predetermined reference frequency, the driving region determiner 110 may determine the driving region as the low frequency driving region.

The driving region determiner 110 may determine the driving region based on a method other than the average driving frequency.

The offset setting unit 120 may generate an operating frequency offset of the dual inverter compressor 10 based on the driving region.

Referring to FIG. 3, a vibration waveform obtained by combining the operating frequency of the first inverter compressor 11 and the operating frequency of the second inverter compressor 16 according to the operating frequency offset may be seen.

When two inverter compressors 11 and 16 are operated at the same operating frequency, the amplitude of the inverter is twice as high as that of one inverter compressor, and the vibration energy applied to the pipe or the set is large because it is operated at one frequency. .

On the other hand, when the operating frequencies of the two inverter compressors 11 and 16 are constantly different, the maximum amplitude is the same as when operating at the same operating frequency, but the vibration energy applied to the pipe or the set is reduced. .

In addition, as the difference between the operating frequencies of the first inverter compressor 11 and the second inverter compressor 16 increases, the vibration energy applied to the pipe becomes smaller.

On the other hand, in order to minimize the vibration energy applied to the pipe, it is advantageous to increase the difference between the operating frequency of the first inverter compressor 11 and the second inverter compressor 16, but to maintain an appropriate offset in terms of the reliability of the refrigerant cycle It is necessary.

Because, as the offset is increased, the oil characteristics of the compressor are significantly different, so there may be a difference in oil level between the two inverter compressors 11 and 16, and a problem in performance and reliability may occur due to pressure loss due to the difference in flow rate. Because it can.

In addition, when the offset is large, the maximum performance may be degraded due to the influence of the low operating frequency at the maximum operating frequency.

Therefore, the offset setting unit 120 generates an operation frequency offset to set the operation frequency of the first inverter compressor 11 and the second inverter compressor 16 differently when the dual compressor 10 operates, and applies it to the pipe and the set. Loss of vibration can be minimized.

In addition, the offset setting unit 120 may set the operating frequency offset in the high frequency operating region and the low frequency operating region differently to reduce the vibration applied to the pipe and the set and at the same time increase the cycle reliability.

First, the offset setting unit 120 may receive information about which driving region the dual inverter compressor 10 operates in the high frequency operating region and the low frequency operating region from the driving region determination unit 110.

If the dual inverter compressor 10 operates in the high frequency driving region, the offset setting unit 120 may set the driving frequency offset to a first predetermined frequency.

Here, the first frequency is an operating frequency offset indicating a difference between operating frequencies of the first inverter compressor 11 and the second inverter compressor 16 in the high frequency operating region.

For example, the first frequency may comprise 3 Hz.

In the high frequency operation region, the compressor oil characteristics are greatly different as the operation frequency offset increases. Therefore, oil level difference may occur between the two inverter compressors 11 and 16. May occur.

Therefore, in order to solve the above problem, the operating frequency offset may be set to a value smaller than the operating frequency offset in the low frequency driving region in the high frequency driving region.

If the dual inverter compressor 10 operates in the low frequency driving region, the offset setting unit 120 may set the driving frequency offset to a second predetermined frequency.

Here, the second frequency is an operating frequency offset indicating a difference between operating frequencies of the first inverter compressor 11 and the second inverter compressor 16 in the low frequency driving region.

For example, the second frequency may comprise 5 Hz.

As described above, in the low frequency driving region, the operating frequency offset can be set to a value larger than the operating frequency offset in the high frequency driving region.

The offset setting unit 120 may transmit the generated driving frequency offset to the controller 130.

The controller 130 generates operating frequencies of the first and second inverter compressors 11 and 16 based on the operating frequency offset, and generates a dual inverter based on the operating frequencies of the first and second inverter compressors 11 and 16. A control signal for driving the compressor can be generated.

The controller 130 may determine the operating frequencies of the first and second inverter compressors 11 and 16 based on the average operating frequency transmitted from the operation region determining unit 110 and the operating frequency offset received from the offset setting unit 120. Can be generated.

The controller 130 controls the operating frequencies of the first and second inverter compressors 11 and 16 such that a difference between the operating frequency of the first inverter compressor 11 and the operating frequency of the second inverter compressor 16 becomes an operating frequency offset. Can be generated.

For example, the controller 130 may generate an operating frequency of the first inverter compressor 11 by subtracting a half of the operating frequency offset from the average operating frequency.

In addition, the controller 130 may generate the operating frequency of the second inverter compressor 16 by adding the half of the operating frequency offset to the average operating frequency.

Then, the controller 130 generates a control signal for driving the first inverter compressor 11 based on the operating frequency of the first inverter compressor 11, and based on the operating frequency of the second inverter compressor 16. The control signal for driving the second inverter compressor 16 may be generated.

The first inverter compressor driver 142 receives a control signal for driving the first inverter compressor 11 from the controller 130, and drives the first inverter compressor 11 at an operating frequency of the first inverter compressor 11. can do.

The second inverter compressor driver 144 receives a control signal for driving the second inverter compressor 16 from the controller 130 and drives the second inverter compressor 16 at an operating frequency of the second inverter compressor 16. can do.

4 is a flowchart illustrating a control method of an air conditioner according to an embodiment of the present invention.

As shown in FIG. 4, the control method of the air conditioner includes the operation area determining unit 110, the offset setting unit 120, the control unit 130, the first inverter compressor driving unit 142, And the second inverter compressor driver 144.

When the indoor unit 2 is driven, an operating frequency of the dual inverter compressor 10 may be set in order to provide cooling capability required by the indoor unit 2 (1010).

In this case, an average operating frequency of the dual inverter compressor 10 may be calculated, and an operating region may be determined based on the average operating frequency (1020 and 1030).

If the average driving frequency is greater than or equal to the first predetermined reference frequency (YES in step 1030), the driving region may be determined as the high frequency driving region.

If the average driving frequency is less than the first predetermined reference frequency (NO in step 1030), the driving region may be determined as the low frequency driving region.

Then, the operating frequency offset of the dual inverter compressor 10 may be generated based on the operating region.

If the dual inverter compressor 10 operates in the high frequency driving region, the operating frequency offset may be set to a first predetermined frequency (1040).

If the dual inverter compressor 10 operates in the low frequency driving region, the operating frequency offset may be set to a second predetermined frequency (1050).

Then, an operating frequency of the first and second inverter compressors 11 and 16 is generated based on the operating frequency offset, and the dual inverter compressor is generated based on the operating frequencies of the first and second inverter compressors 11 and 16. A driving control signal may be generated (1060 and 1070).

5 is a view showing a pipe stress according to the offset degree of the air conditioner according to an embodiment of the present invention.

Referring to FIG. 5, it can be seen that the pipe stresses according to the operating frequency offset are compared in the low frequency driving region (when the reference frequency is set to 50 Hz).

In the case of cooling operation, when there is no offset of an operating frequency, there exists a wide area | region (dark area shown in bold box) in which the peak value of piping stress is large.

However, when the offset of the operating frequency is 5 Hz, it can be seen that the section in which the peak value of the pipe stress is large (indicated by a dark box in dark) is greatly reduced.

In the case of heating operation, when the operating frequency offset is 5 Hz, the section in which the peak value of the pipe stress is large (indicated by the dark box in bold box) is reduced than when the operating frequency offset is 3 Hz. .

As described above, the air conditioner according to an embodiment of the present invention sets the operation frequency of the first inverter compressor 11 and the second inverter compressor 16 differently during the operation of the dual inverter compressor 10, the pipe and the set It is possible to minimize the vibration applied to.

In addition, the air conditioner according to the embodiment of the present invention can set the operation frequency offset differently in the high frequency operation region and the low frequency operation region to reduce the vibration applied to the pipe and the set and at the same time increase the cycle reliability.

Hereinafter, an air conditioner according to another embodiment of the present invention will be described with reference to FIG. 1.

6 is a view showing a control block diagram of an air conditioner according to another embodiment of the present invention, Figures 7a and 7b is a view showing the oil flow amount according to the model of the compressor according to another embodiment of the present invention.

As shown in FIG. 6, the air conditioner includes a frequency allocator 115, a frequency variation detector 125, a controller 130, a first compressor driver 142, a second compressor driver 144, and a first compressor. 11, a second compressor 16, a first oil separator 12, and a second oil separator 17.

Although one outdoor unit 1 is illustrated in FIG. 1 and two compressors 11 and 16 are represented, the present invention is not limited thereto. An air conditioner according to another embodiment of the present invention includes at least one outdoor unit 1 and at least one unit. It may include the indoor unit (2).

The outdoor unit 1 may include at least one compressor 11, 16, and the compressor 11, 16 may include an inverter compressor capable of changing an operating frequency or a constant speed compressor having a constant operating frequency.

The first compressor driver 142, the second compressor driver 144, the first oil separator 12, and the second oil separator 17 have the same contents as those described with reference to FIG. 1, and thus descriptions thereof will be omitted.

An air conditioner according to another embodiment of the present invention will be described by dividing the case in which at least one compressor (11, 16) is composed of both inverter compressor and at least one constant speed compressor.

First, an air conditioner according to another embodiment of the present invention will be described in the case where at least one compressor (11, 16) are all composed of an inverter compressor.

Referring to FIGS. 7A and 7B, the oil flow rates of the inverter compressors 11 and 16 are inherent characteristics of the individual inverter compressors 11 and 16, but in general, as the amount of oil inside the inverter compressors 11 and 16 increases, the amount of oil increases and the inverter The higher the operating frequency of the compressors 11 and 16, the greater the tendency to increase.

As described above, the oil amount of the inverter compressors 11 and 16 is uniformly distributed by using the principle that the oil amount of the inverter compressors 11 and 16 increases as the oil amount of the inverter compressors 11 and 16 increases. It is called.

Since the inverter compressors 11 and 16 in a single multi air conditioner system share an operating environment such as an outdoor temperature and an indoor temperature, the difference due to the suction pressure, the discharge pressure, and the suction temperature of the inverter compressors 11 and 16 is insignificant. .

That is, if the soil characteristics of the inverter compressors 11 and 16 of different models are known, even if a plurality of inverter compressors 11 and 16 of different models are installed in a single multi-air conditioner system, the difference in the relative oil volume can be obtained. It can be predicted as a function of the operating frequencies of the compressors 11 and 16.

The frequency allocator 115 may calculate operating frequencies of all inverter compressors 11 and 16 when the indoor unit 2 is turned on.

In the multi-system air conditioner, the operating frequencies of the entire inverter compressors 11 and 16 are determined according to the driving load required by the indoor unit 2.

In the state in which the operating frequencies of all the inverter compressors 11 and 16 are determined, the amount of oil for each compressor can be made uniform through the allocation of the operating frequency for each inverter compressor 11 and 16.

At this time, the frequency allocating unit 115 assumes the same oil amount according to the oil flow characteristics of the inverter compressors 11 and 16, and the operating frequency such that the amount of oil discharged from the at least one inverter compressors 11 and 16 is the same. Can be assigned.

In addition, the frequency allocating unit 115 has a difference between the maximum operating frequency and the minimum operating frequency among the operating frequencies of the at least one inverter compressor 11, 16 based on the driving load required by the indoor unit 2. The operating frequencies of the at least one inverter compressor 11, 16 may be assigned to be below the frequency.

Here, the second reference frequency is a difference value between the maximum operating frequency and the minimum operating frequency serving as a reference for making the oil amount uniform in the air conditioner composed of only the plurality of inverter compressors 11 and 16.

For example, the second reference frequency may comprise 40 Hz.

As described above, when the operating frequencies of the at least one inverter compressors 11 and 16 are allocated such that the difference between the maximum operating frequency and the minimum operating frequency is equal to or less than the second reference frequency, the oil amount of the inverter compressors 11 and 16 is actually increased. Even if the oil amount is different, the amount of oil for each compressor reaches the same level according to the characteristics of increasing the amount of oil.

For example, the inverter compressors 11 and 16 of the different models of Figs. 7A and 7B have the same amount of oil as that of the inverter compressor 11 of Fig. 7B when the frequency is the same. It is about 5% larger than that.

However, if the two inverter compressors 11 and 16 are mounted in the same system and the rotational frequency difference of the two inverter compressors 11 and 16 is limited to within the second predetermined reference frequency, the oil flow rate can also obtain almost similar results.

When the two inverter compressors 11 and 16 are operated for a predetermined time in such a state that the oil quantity is almost similar, the oil amount of the two inverter compressors 11 and 16 becomes uniform.

The frequency variation detecting unit 125 may detect whether a difference value between the maximum driving frequency and the minimum driving frequency is greater than the second reference frequency.

After the oil amounts of the two inverter compressors 11 and 16 become uniform, the oil amounts of the two inverter compressors 11 and 16 may again vary due to various circumstances.

For example, when an abnormality occurs in one of the compressors and the protection control is performed, it is necessary to abnormally lower the operating frequency of the compressor.

In addition, when the indoor unit is additionally turned on, it is necessary to turn on a new inverter compressor because the total compressor operating frequency increases. However, the operating frequency is zero immediately after the new inverter compressor is turned on. It will have a value close to Hz.

In the above two cases, the difference between the maximum operating frequency and the minimum operating frequency among the plurality of inverter compressors may be greater than the second reference frequency.

If the operating frequency difference between the two inverter compressors 11 and 16 continues to be larger than the second reference frequency, the oil amount of the two inverter compressors 11 and 16 is unbalanced.

Therefore, in order to make the oil amount of the two inverter compressors 11 and 16 even again, it is necessary to adjust the operating frequency difference within the second reference frequency.

To this end, the frequency allocator 115 re-allocates the operating frequencies of the at least one inverter compressor when the first reference time elapses from the time when the difference between the maximum operating frequency and the minimum operating frequency becomes greater than the second reference frequency. can do.

Here, the first reference time is a time taken to start the control to uniform the oil amount of the two inverter compressors 11 and 16 again while the difference between the maximum operating frequency and the minimum operating frequency is greater than the second reference frequency. it means.

For example, the first reference time may have a value within 2 hours.

In addition, the frequency allocating unit 115 increases or decreases the operating frequencies of the at least one inverter compressor 11, 16 or stops the operation of the at least one inverter compressor 11, 16, thereby allowing the maximum operating frequency and the minimum operating frequency. The operating frequencies of the at least one inverter compressor 11 and 16 may be allocated such that a difference value of the first or less inverter becomes less than or equal to the second reference frequency.

The controller 130 may generate a control signal for driving the at least one inverter compressor 11, 16 based on the assigned operating frequencies to uniform the amount of oil in the at least one inverter compressor 11, 16. have.

Hereinafter, a case in which an air conditioner according to another embodiment of the present invention includes at least one constant speed compressor will be described.

In the following description, the first compressor 11 illustrated in FIG. 6 is an inverter compressor, and the second compressor 16 is a constant speed compressor.

In the following description, it is assumed that there are two compressors, but the present invention is not limited thereto, and the number of compressors may be two or more.

As shown in FIG. 6, an air conditioner according to another embodiment of the present invention includes a frequency allocator 115, a frequency variation detector 125, a controller 130, a first compressor driver 142, and a second compressor. The driving unit 144, the inverter compressor 11, the constant speed compressor 16, the first oil separator 12, and the second oil separator 17 may be included.

The constant speed compressor 16 refers to a compressor that operates at a constant frequency.

The constant speed compressor 16 has the same characteristics as the inverter compressor 11 except for the constant operating frequency.

Therefore, the oil amount of the constant speed compressor 16 tends to increase as the amount of oil in the constant speed compressor 16 increases, as in the inverter compressor 11.

The inverter compressor 11, the first compressor driver 142, the second compressor driver 144, the first oil separator 12, and the second oil separator 17 have the same contents as those described with reference to FIG. 1, and thus descriptions thereof are omitted. Let's do it.

The frequency allocator 115 may calculate operating frequencies of the entire compressors 11 and 16 when the indoor unit 2 is turned on.

In the multi-system air conditioner, the operating frequencies of the entire compressors 11 and 16 are determined according to the driving load required by the indoor unit 2.

The frequency allocating unit 115 may uniformize the amount of oil for each compressor by allocating the operating frequency of the inverter compressor 11 in a state in which the operating frequencies of all the compressors 11 and 16 are determined.

In this case, the frequency allocator 115 assumes the same oil amount according to the oil flow characteristics of the inverter compressor 11 and the constant speed compressor 16, and the amount of oil discharged from the inverter compressor 11 is constant speed compressor 16. The operating frequency of the inverter compressor 11 may be assigned to be equal to the amount of oil discharged from the.

In addition, the frequency allocating unit 115 has a third difference between the maximum operating frequency and the minimum operating frequency among operating frequencies of the inverter compressor 11 and the constant speed compressor 16 based on the driving load required by the indoor unit 2. The operating frequency of the inverter compressor 11 can be assigned so that it becomes below the reference frequency.

Here, the third reference frequency is a difference value between the maximum operating frequency and the minimum operating frequency, which become a reference for making the oil amount uniform in the air conditioner including the at least one constant speed compressor 16.

When at least one constant speed compressor 16 is included, the operation frequency of each compressor is limited in a state in which the total compressor operating frequency in the system is determined. Thus, the third reference frequency may have a value greater than or equal to the second reference frequency.

For example, the third reference frequency may comprise 60 Hz.

As described above, when the operating frequency of the inverter compressor 11 is assigned such that the difference between the maximum operating frequency and the minimum operating frequency is equal to or less than the third reference frequency, the oil amount of the inverter compressor 11 and the constant speed compressor 16 actually differs. Even if the amount of oil increases, the amount of oil for each compressor reaches the same level according to the characteristics of increasing the amount of oil.

That is, even if the amount of oil between the inverter compressor 11 and the constant speed compressor 16 is different, the inverter compressor 11 and the constant speed compressor 16 are fixed in a state where the oil quantity is almost similar by adjusting the operating frequency of the inverter compressor 11. When operating for a time, the oil amount of the inverter compressor 11 and the constant speed compressor 16 becomes uniform eventually.

The frequency variation detecting unit 125 may detect whether the difference between the maximum operating frequency and the minimum operating frequency is greater than the third reference frequency among the operating frequencies of the plurality of compressors.

After the oil amounts of the inverter compressor 11 and the constant speed compressor 16 become uniform, the oil amounts of the two compressors 11 and 16 may differ again due to various circumstances.

For example, when an abnormality occurs in one of the compressors and the protection control is performed, it is necessary to abnormally lower the operating frequency of the compressor.

In addition, when the indoor unit is additionally turned on, it is necessary to turn on a new compressor because the total compressor operating frequency is increased. Immediately after the new compressor is turned on, the operating frequency is set to 0 Hz. It will have a close value.

In the above two cases, the difference between the maximum operating frequency and the minimum operating frequency among the plurality of compressors may be greater than the third reference frequency.

If the difference between the operating frequency of the inverter compressor 11 and the operating frequency of the constant speed compressor 16 is maintained higher than the third reference frequency, the oil amounts of the two compressors 11 and 16 become unbalanced.

Therefore, in order to make the oil amount of the two compressors 11 and 16 uniform again, it is necessary to adjust the operating frequency difference within the third reference frequency.

To this end, the frequency allocator 115 at least one inverter when the first reference time elapses from the time when the difference between the maximum operating frequency and the minimum operating frequency of the plurality of compressors becomes greater than the third reference frequency. The operating frequencies of the compressor can be reassigned.

Here, the first reference time means a time taken to start the control to uniform the oil amount of the two compressors 11 and 16 again while the difference between the maximum operating frequency and the minimum operating frequency is greater than the third reference frequency. do.

For example, the first reference time may have a value within 2 hours.

In addition, the frequency allocator 115 increases or decreases operating frequencies of the at least one inverter compressor or stops the operation of the at least one inverter compressor such that a difference value between the maximum operating frequency and the minimum operating frequency is less than or equal to the third reference frequency. It is possible to assign operating frequencies of at least one inverter compressor.

However, when at least one constant speed compressor is included, frequency allocation for each compressor may be limited in a state where operating frequencies of all the compressors in the system are determined.

Therefore, even if the difference between the maximum operating frequency and the minimum operating frequency is greater than the third reference frequency, the frequency allocating unit 115 operates the inverter compressor above or below the load artificially required for the redistribution of the oil amount. In addition, the compressor may be operated such that the difference between the maximum operating frequency and the minimum operating frequency is less than or equal to the third reference frequency.

That is, the frequency allocator 115 increases or decreases the operating frequencies of the at least one inverter compressor or stops the operation of the at least one inverter compressor, so that the difference value between the maximum operating frequency and the minimum operating frequency for the second reference time is equal to the third. The operating frequencies of the at least one inverter compressor may be assigned to be greater than the reference frequency.

Here, the second reference time means a time for operating the inverter compressor above or below the load required by the indoor unit for redistribution of the oil amount.

For example, the second reference time may be 2 hours or less.

Then, the frequency allocator 115 may again allocate the operating frequencies of the at least one inverter compressor such that the operating frequencies of the plurality of compressors become less than or equal to the third reference frequency. .

The controller 130 generates a control signal for driving the at least one inverter compressor and the at least one constant speed compressor based on the assigned operating frequencies to uniform the amount of oil in the at least one inverter compressor and the at least one constant speed compressor. Can be.

8 is a flowchart illustrating a control method of an air conditioner according to another embodiment of the present invention.

As shown in FIG. 8, the control method of the air conditioner includes the frequency allocator 115, the frequency variation detector 125, the controller 130, the first compressor driver 142, and the second compressor described with reference to FIG. 6. It may be implemented by the driver 144.

When the indoor unit 2 is driven (2010), it is possible to calculate the operating capacity of the entire compressor in order to provide the cooling capacity required by the indoor unit (2020).

Then, the operating frequencies of the at least one compressor are set such that the difference between the maximum operating frequency and the minimum operating frequency among the operating frequencies of the at least one compressor is less than or equal to the second reference frequency based on the driving load required by the indoor unit 2. May be allocated (2030).

Then, a control signal for driving the at least one compressor may be generated based on the assigned operating frequencies to uniform the amount of oil in the at least one compressor (2040).

After the two compressors are operated for a predetermined time, the oil amount of the two compressors becomes uniform, and then it may be determined whether the difference between the maximum operating frequency and the minimum operating frequency is greater than the second reference frequency (2050).

If the difference between the maximum operating frequency and the minimum operating frequency is greater than or equal to the second reference frequency (YES in step 2050), the difference between the maximum operating frequency and the minimum operating frequency becomes greater than the second reference frequency. 1 It is determined whether the reference time has elapsed (2060).

If the first reference time elapses (“YES” in step 2060), the process moves to step 2020 to reassign operation frequencies of all compressors (2060).

Up to now, the air conditioner has been described based on a plurality of inverter compressors. However, when the air conditioner includes at least one constant speed compressor, the same condition except for replacing the second reference frequency with the third reference frequency is described in FIG. Can be controlled in a manner.

11: first compressor 12: first oil separator
16 second compressor 17 second oil separator
110: operation area determination unit 115: frequency allocation unit
120: offset setting unit 125: frequency variation detection unit
130: control unit 142: first compressor driving unit
144: second compressor drive unit

Claims (19)

A dual inverter compressor including a first inverter compressor and a second inverter compressor;
An operation region determination unit configured to determine in which operation region the dual inverter compressor operates in a high frequency operation region and a low frequency operation region;
An offset setting unit which generates an operating frequency offset of the dual inverter compressor based on the operating area; And
A controller configured to generate an operating frequency of the first and second inverter compressors based on the operating frequency offset and to generate a control signal for driving the dual inverter compressor based on the operating frequencies of the first and second inverter compressors
Including,
The control unit,
And an operating frequency offset of the operating frequency of the first inverter compressor and the operating frequency of the second inverter compressor to be the operating frequency offset. The method of claim 1,
And the operation region determining unit calculates an average operating frequency of the dual inverter compressor, and determines the operating region based on the average operating frequency. The method of claim 1,
The offset setting unit,
And when the dual inverter compressor operates in the high frequency driving region, determining the operating frequency offset as a first predetermined frequency. The method of claim 1,
The offset setting unit,
And when the dual inverter compressor operates in the low frequency driving region, determining the operating frequency offset as a second predetermined frequency. delete In the control method of the air conditioner comprising a dual inverter compressor including a first inverter compressor and a second inverter compressor,
Determining which operating region the dual inverter compressor operates in a high frequency operating region and a low frequency operating region;
Generate an operating frequency offset of the dual inverter compressor based on the operating region;
Generate operating frequencies of the first and second inverter compressors based on the operating frequency offset;
Driving the dual inverter compressor based on operating frequencies of the first and second inverter compressors,
Generating operating frequencies of the first and second inverter compressors includes controlling a difference between an operating frequency of the first inverter compressor and an operating frequency of the second inverter compressor to be the operating frequency offset. Way. The method of claim 6,
The determining of the operation region includes calculating an average operating frequency of the dual inverter compressor, and determining the operating region based on the average operating frequency. The method of claim 6,
Generating the driving frequency offset includes determining the driving frequency offset as a first predetermined frequency when the dual inverter compressor operates in the high frequency driving region. The method of claim 6,
Generating the operating frequency offset includes determining the operating frequency offset as a second predetermined frequency when the dual inverter compressor operates in the low frequency driving region. delete At least one inverter compressor for compressing and discharging the refrigerant containing oil and changing an operating frequency;
At least one oil separator which separates oil mixed in the refrigerant discharged from the at least one inverter compressor and returns the oil to the at least one inverter compressor;
Allocating operating frequencies of the at least one inverter compressor such that a difference value between the maximum operating frequency and the minimum operating frequency among the operating frequencies of the at least one inverter compressor is equal to or less than a second reference frequency based on a driving load required by an indoor unit. Frequency allocation unit;
A frequency variation detector for detecting whether a difference between the maximum driving frequency and the minimum driving frequency is greater than the second reference frequency; And
A controller for generating a control signal for driving the at least one inverter compressor based on the assigned operating frequencies to equalize the amount of oil of the at least one inverter compressor.
Air conditioner comprising a. The method of claim 11,
And the frequency assigning unit assigns the operating frequencies such that the amount of oil discharged from the at least one inverter compressor is the same. The method of claim 11,
And the frequency allocation unit re-assigns operating frequencies of the at least one inverter compressor when a first reference time elapses from a time when the difference value becomes larger than the second reference frequency. The method of claim 13,
Reassigning operating frequencies of the at least one inverter compressor increases or decreases the operating frequencies of the at least one inverter compressor or stops the operation of the at least one inverter compressor, such that the difference between the maximum operating frequency and the minimum operating frequency Assigning operating frequencies of the at least one inverter compressor to be less than or equal to the second reference frequency. At least one inverter compressor for compressing and discharging the refrigerant containing oil and changing an operating frequency;
At least one constant speed compressor that compresses and discharges a refrigerant containing oil and has a constant operating frequency;
At least one oil separator which separates oil mixed in the refrigerant discharged from the at least one inverter compressor and the at least one constant speed compressor and returns the oil to the at least one inverter compressor and the at least one constant speed compressor;
The at least one inverter such that a difference between the maximum operating frequency and the minimum operating frequency among the operating frequencies of the at least one inverter compressor and the at least one constant speed compressor is equal to or less than a third reference frequency based on a driving load required by an indoor unit; A frequency allocator for allocating operating frequencies of the compressor; And
Generating a control signal for driving the at least one inverter compressor and the at least one constant speed compressor based on the assigned operating frequencies to equalize the amount of oil in the at least one inverter compressor and the at least one constant speed compressor; Control
Air conditioner comprising a. The method of claim 15,
And the frequency allocation unit assigns operating frequencies of the at least one inverter compressor such that the amount of oil discharged from the at least one inverter compressor is equal to the amount of oil discharged from the at least one constant speed compressor. The method of claim 15,
And a frequency detector configured to detect whether a difference between the maximum driving frequency and the minimum driving frequency is greater than the third reference frequency.
The operation frequency allocator includes re-assigning operating frequencies of the at least one inverter compressor when a first reference time elapses from the time when the difference value becomes greater than the third reference frequency. The method of claim 17,
Reassigning operating frequencies of the at least one inverter compressor increases or decreases the operating frequencies of the at least one inverter compressor or stops the operation of the at least one inverter compressor, such that the difference between the maximum operating frequency and the minimum operating frequency Assigning operating frequencies of the at least one inverter compressor to be less than or equal to the third reference frequency. The method of claim 17,
Reassigning operating frequencies of the at least one inverter compressor increases or decreases the operating frequencies of the at least one inverter compressor or stops operation of at least one inverter compressor, such that the maximum operating frequency and the minimum Allocating operating frequencies of the at least one inverter compressor such that a difference value of the operating frequencies is greater than a third reference frequency.

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