阅读说明：本技术 空调器、多联机空调系统的回油控制方法和存储介质 (Air conditioner, oil return control method of multi-split air conditioning system and storage medium ) 是由 刘群波 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种空调器、多联机空调系统的回油控制方法和存储介质,所述多联机空调系统的回油控制方法在所述室内机开启数量小于预设数量阈值和/或所述室内机开启数量与所述室内机总数的比值小于预设比值阈值时,即表示当前多联机空调系统中的室内机开机数量较少,通过调小或关闭当前开机室内机的电子膨胀阀,并控制当前关机室内机的电子膨胀阀以预设开度运行,以使高速流通的冷媒流经当前不运行的室内机管路,保证回油运行的同时,不经过当前运行中的室内机管路,减小回油运行产生的噪音对用户的影响,提升用户体验,解决了多联机空调系统的回油运行容易产生较大噪音的技术问题。(The invention discloses an air conditioner, an oil return control method of a multi-split air conditioning system and a storage medium, when the opening number of the indoor units is smaller than a preset number threshold value and/or the ratio of the opening number of the indoor units to the total number of the indoor units is smaller than a preset ratio threshold value, that is, the number of the indoor units in the current multi-split air conditioning system is small, the electronic expansion valve of the current indoor unit is turned down or closed, and the electronic expansion valve of the current indoor unit is controlled to operate at the preset opening degree, so that the refrigerant flowing at high speed flows through the indoor unit pipeline which is not operated at present, the oil return operation is ensured, at the same time, the air conditioner air-conditioning system has the advantages that the air conditioner air-conditioning system does not pass through an indoor unit pipeline in the current operation, the influence of noise generated by oil return operation on a user is reduced, the user experience is improved, and the technical problem that the oil return operation of the multi-split air-conditioning system easily generates large noise is solved.)

1. The oil return control method of the multi-split air conditioning system is characterized by comprising at least two indoor units, and comprises the following steps:

when an oil return operation instruction is detected, the starting number of indoor units and the total number of the indoor units in the multi-split air-conditioning system are obtained;

when the number of the started indoor units is smaller than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is smaller than a preset ratio threshold, determining a currently started indoor unit and a currently stopped indoor unit in the multi-split air-conditioning system;

and reducing or closing the first electronic expansion valve of the currently started indoor unit, and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree to finish oil return operation.

2. The oil return control method of the multi-split air conditioning system according to claim 1, wherein after the step of obtaining the number of the indoor units in the multi-split air conditioning system that are turned on and the total number of the indoor units when the oil return operation command is detected, the method further comprises:

when the number of the started indoor units is not less than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is not less than a ratio threshold, acquiring the system high-pressure of the multi-split air-conditioning system;

determining a second opening degree corresponding to the first electronic expansion valve based on the system high-pressure, wherein the second opening degree is smaller than a preset opening degree threshold value;

and controlling the first electronic expansion valve to operate at the second opening degree, and controlling the second electronic expansion valve to operate at the third opening degree, wherein the third opening degree is greater than the preset opening degree threshold value, and finishing oil return operation.

3. The oil return control method of a multi-split air conditioning system as claimed in claim 2, wherein the step of determining the second opening degree corresponding to the first electronic expansion valve based on the system high pressure specifically includes:

judging whether the high pressure of the system is not less than a maximum pressure threshold value;

and if the high pressure of the system is not less than the maximum pressure threshold value, acquiring an initial opening degree of the first electronic expansion valve, and increasing the initial opening degree by a preset value to be used as the second opening degree, wherein the initial opening degree is less than the preset opening degree threshold value.

4. The oil return control method of a multi-split air conditioning system as claimed in claim 3, wherein after the step of determining whether the system high pressure is not less than a maximum pressure threshold, the method further comprises:

if the system high-pressure is smaller than the maximum pressure threshold, judging whether the system high-pressure is not smaller than a minimum pressure threshold;

and if the system high-pressure is not less than the minimum pressure threshold value, taking the initial opening as the second opening.

5. The oil return control method of a multi-split air conditioning system as claimed in claim 4, wherein after the step of determining whether the system high pressure is not less than a minimum pressure threshold if the system high pressure is less than the maximum pressure threshold, the method further comprises:

and if the high pressure of the system is smaller than the minimum pressure threshold value, reducing the initial opening by a preset value to serve as the second opening.

6. The oil return control method of a multi-split air conditioning system as claimed in claim 2, wherein the multi-split air conditioning system comprises a compressor, a four-way valve, an outdoor unit heat exchanger, an outdoor unit electronic expansion valve, a first indoor unit heat exchanger, a second indoor heat exchanger, and a gas-liquid separator,

the step of controlling the first electronic expansion valve to operate at the second opening degree and the step of controlling the second electronic expansion valve to operate at the third opening degree specifically include:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, and controlling the liquid refrigerant to flow through the first indoor unit heat exchanger and the second indoor unit heat exchanger respectively through a first electronic expansion valve with the opening degree of the second opening degree and a second electronic expansion valve with the opening degree of the third opening degree;

and controlling two paths of refrigerants flowing through the first indoor unit heat exchanger and the second indoor unit heat exchanger to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gaseous refrigerant carrying lubricating oil to flow into the compressor.

7. The oil return control method of a multi-split air conditioning system as claimed in claim 6, wherein the step of turning down or closing the first electronic expansion valve of the currently turned-on indoor unit and controlling the second electronic expansion valve of the currently turned-off indoor unit to operate at the first opening degree comprises:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, turning down or closing the first electronic expansion valve, and controlling the liquid refrigerant to flow through the second indoor unit heat exchanger through a second electronic expansion valve with the opening degree of the first opening degree;

and controlling two paths of refrigerant flowing through the heat exchanger of the second indoor unit to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gas refrigerant carrying lubricating oil to flow into the compressor.

8. The oil return control method of a multi-split air conditioning system as claimed in any one of claims 1 to 7, wherein the step of turning down or closing the first electronic expansion valve of the currently turned-on indoor unit and controlling the second electronic expansion valve of the currently turned-off indoor unit to operate at the first opening degree specifically includes:

the method comprises the steps of obtaining the current high-pressure of the multi-split air-conditioning system, reducing or closing the first electronic expansion valve and determining the opening degree corresponding to the second electronic expansion valve based on the current high-pressure, wherein the first opening degree is larger than a preset opening degree threshold value.

9. An air conditioner, characterized in that the air conditioner comprises a memory, a processor and an oil return control program of a multi-split air conditioning system stored in the memory and operable on the processor, wherein the oil return control program of the multi-split air conditioning system, when executed by the processor, implements the steps of the oil return control method of the multi-split air conditioning system as recited in any one of claims 1 to 8.

10. A computer-readable storage medium, wherein the computer-readable storage medium includes an oil return control program of a multi-split air conditioning system, and the oil return control program of the multi-split air conditioning system, when executed by a processor, implements the steps of the oil return control method of the multi-split air conditioning system according to any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of air conditioners, in particular to an air conditioner, an oil return control method of a multi-split air conditioning system and a computer readable storage medium.

Background

In a multi-split air conditioning system, the long-time operation of the unit can cause a large amount of lubricating oil of the compressor to be discharged into a system pipeline, so that the compressor is lack of oil. In order to solve the problems, the lubricating oil discharged to a system pipeline is returned to the compressor by controlling the oil return operation of the multi-split air conditioning system. When a unit of the existing multi-split air conditioning system enters oil return operation, the flow speed of a system refrigerant is increased mainly by controlling the frequency rise of an outdoor compressor of the air conditioning system and the opening of an electronic expansion valve of an indoor unit to be increased, so that the indoor unit generates large refrigerant flowing sound, noise is increased, and user experience is reduced.

Disclosure of Invention

The invention mainly aims to provide an air conditioner, an oil return control method of a multi-split air conditioning system and a computer readable storage medium, and aims to solve the technical problem that the oil return operation of the multi-split air conditioning system is easy to generate large noise.

In order to achieve the above object, the present invention provides an oil return control method for a multi-split air conditioning system, where the multi-split air conditioning system includes at least two indoor units, and the oil return control method for the multi-split air conditioning system includes the following steps:

when an oil return operation instruction is detected, the starting number of indoor units and the total number of the indoor units in the multi-split air-conditioning system are obtained;

when the number of the started indoor units is smaller than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is smaller than a preset ratio threshold, determining a currently started indoor unit and a currently stopped indoor unit in the multi-split air-conditioning system;

and reducing or closing the first electronic expansion valve of the currently started indoor unit, and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree to finish oil return operation.

In an embodiment, after the step of obtaining the number of the opened indoor units and the total number of the indoor units in the multi-split air conditioning system when the oil return operation instruction is detected, the method further includes:

when the number of the started indoor units is not less than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is not less than a ratio threshold, acquiring the system high-pressure of the multi-split air-conditioning system;

determining a second opening degree corresponding to the first electronic expansion valve based on the system high-pressure, wherein the second opening degree is smaller than a preset opening degree threshold value;

and controlling the first electronic expansion valve to operate at the second opening degree, and controlling the second electronic expansion valve to operate at the third opening degree, wherein the third opening degree is greater than the preset opening degree threshold value, and finishing oil return operation.

In an embodiment, the step of determining the second opening degree corresponding to the first electronic expansion valve based on the system high pressure specifically includes:

judging whether the high pressure of the system is not less than a maximum pressure threshold value;

and if the high pressure of the system is not less than the maximum pressure threshold value, acquiring an initial opening degree of the first electronic expansion valve, and increasing the initial opening degree by a preset value to be used as the second opening degree, wherein the initial opening degree is less than the preset opening degree threshold value.

In one embodiment, after the step of determining whether the system high pressure is not less than the maximum pressure threshold, the method further includes:

if the system high-pressure is smaller than the maximum pressure threshold, judging whether the system high-pressure is not smaller than a minimum pressure threshold;

and if the system high-pressure is not less than the minimum pressure threshold value, taking the initial opening as the second opening.

In an embodiment, after the step of determining whether the system high pressure is not less than the minimum pressure threshold if the system high pressure is less than the maximum pressure threshold, the method further includes:

and if the high pressure of the system is smaller than the minimum pressure threshold value, reducing the initial opening by a preset value to serve as the second opening.

In one embodiment, the multi-split air conditioning system comprises a compressor, a four-way valve, an outdoor heat exchanger, an outdoor electronic expansion valve, a first indoor heat exchanger, a second indoor heat exchanger and a gas-liquid separator,

the step of controlling the first electronic expansion valve to operate at the second opening degree and the step of controlling the second electronic expansion valve to operate at the third opening degree specifically include:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, and controlling the liquid refrigerant to flow through the first indoor unit heat exchanger and the second indoor unit heat exchanger respectively through a first electronic expansion valve with the opening degree of the second opening degree and a second electronic expansion valve with the opening degree of the third opening degree;

and controlling two paths of refrigerants flowing through the first indoor unit heat exchanger and the second indoor unit heat exchanger to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gaseous refrigerant carrying lubricating oil to flow into the compressor.

In an embodiment, the step of turning down or closing the first electronic expansion valve of the currently turned-on indoor unit and controlling the second electronic expansion valve of the currently turned-off indoor unit to operate at the first opening degree includes:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, turning down or closing the first electronic expansion valve, and controlling the liquid refrigerant to flow through the second indoor unit heat exchanger through a second electronic expansion valve with the opening degree of the first opening degree;

and controlling two paths of refrigerant flowing through the heat exchanger of the second indoor unit to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gas refrigerant carrying lubricating oil to flow into the compressor.

In an embodiment, the step of turning down or closing the first electronic expansion valve of the currently started indoor unit and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree specifically includes:

the method comprises the steps of obtaining the current high-pressure of the multi-split air-conditioning system, reducing or closing the first electronic expansion valve and determining the opening degree corresponding to the second electronic expansion valve based on the current high-pressure, wherein the first opening degree is larger than a preset opening degree threshold value.

In order to achieve the above object, the present invention further provides an air conditioner, where the air conditioner includes a memory, a processor, and an oil return control program of a multi-split air conditioning system stored in the memory and operable on the processor, and the oil return control program of the multi-split air conditioning system, when executed by the processor, implements the steps of the oil return control method of the multi-split air conditioning system as described above.

In order to achieve the above object, the present invention further provides a computer-readable storage medium, where the computer-readable storage medium includes an oil return control program of a multi-split air conditioning system, and the oil return control program of the multi-split air conditioning system, when executed by a processor, implements the steps of the oil return control method of the multi-split air conditioning system as described above.

According to the air conditioner, the oil return control method of the multi-split air conditioning system and the computer readable storage medium, the number of the indoor units in the multi-split air conditioning system to be started and the total number of the indoor units are obtained when an oil return operation instruction is detected; when the number of the started indoor units is smaller than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is smaller than a preset ratio threshold, determining a currently started indoor unit and a currently stopped indoor unit in the multi-split air-conditioning system; and reducing or closing the first electronic expansion valve of the currently started indoor unit, and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree to finish oil return operation. Through the mode, when the opening number of the indoor units is smaller than the preset number threshold and/or the ratio of the opening number of the indoor units to the total number of the indoor units is smaller than the preset ratio threshold, the method indicates that the starting number of the indoor units in the multi-split air-conditioning system is less, the electronic expansion valve of the currently started indoor unit is turned down or closed, and the electronic expansion valve of the currently shut-down indoor unit is controlled to operate at the preset opening degree, so that the high-speed circulating refrigerant flows through the indoor unit pipeline which is not operated currently, the oil return operation is ensured, meanwhile, the indoor unit pipeline which is operated currently is not passed through, the influence of noise generated by the oil return operation on a user is reduced, the user experience is improved, and the technical problem that the oil return operation of the multi-split air-conditioning system is easy to generate larger noise is solved.

Drawings

FIG. 1 is a schematic diagram of a hardware structure of an air conditioner according to an embodiment of the present invention;

fig. 2 is a schematic flowchart illustrating an oil return control method of a multi-split air conditioning system according to a first embodiment of the present invention;

fig. 3 is a schematic flowchart illustrating an oil return control method of a multi-split air conditioning system according to a second embodiment of the present invention;

fig. 4 is a flowchart illustrating an oil return control method of a multi-split air conditioning system according to a third embodiment of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The main solution of the embodiment of the invention is as follows: when an oil return operation instruction is detected, the starting number of indoor units and the total number of the indoor units in the multi-split air-conditioning system are obtained; when the number of the started indoor units is smaller than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is smaller than a preset ratio threshold, determining a currently started indoor unit and a currently stopped indoor unit in the multi-split air-conditioning system; and reducing or closing the first electronic expansion valve of the currently started indoor unit, and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree to finish oil return operation. Through the mode, when the opening number of the indoor units is smaller than the preset number threshold and/or the ratio of the opening number of the indoor units to the total number of the indoor units is smaller than the preset ratio threshold, the method indicates that the starting number of the indoor units in the multi-split air-conditioning system is less, the electronic expansion valve of the currently started indoor unit is turned down or closed, and the electronic expansion valve of the currently shut-down indoor unit is controlled to operate at the preset opening degree, so that the high-speed circulating refrigerant flows through the indoor unit pipeline which is not operated currently, the oil return operation is ensured, meanwhile, the indoor unit pipeline which is operated currently is not passed through, the influence of noise generated by the oil return operation on a user is reduced, the user experience is improved, and the technical problem that the oil return operation of the multi-split air-conditioning system is easy to generate larger noise is solved.

As one implementation, the air conditioner may be as shown in fig. 1.

The embodiment of the invention relates to an air conditioner, which comprises: a processor 1001 (e.g., a CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Wherein a communication bus 1002 is used to enable connective communication between these components.

The memory 1005 may be a high-speed RAM memory or a non-volatile memory (e.g., a magnetic disk memory). As shown in fig. 1, an oil return control program of the multi-split air conditioning system may be included in a memory 1005, which is a kind of computer storage medium; and the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

when an oil return operation instruction is detected, the starting number of indoor units and the total number of the indoor units in the multi-split air-conditioning system are obtained;

when the number of the started indoor units is smaller than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is smaller than a preset ratio threshold, determining a currently started indoor unit and a currently stopped indoor unit in the multi-split air-conditioning system;

and reducing or closing the first electronic expansion valve of the currently started indoor unit, and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree to finish oil return operation.

In an embodiment, the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

when the number of the started indoor units is not less than a preset number threshold and/or the ratio of the number of the started indoor units to the total number of the indoor units is not less than a ratio threshold, acquiring the system high-pressure of the multi-split air-conditioning system;

determining a second opening degree corresponding to the first electronic expansion valve based on the system high-pressure, wherein the second opening degree is smaller than a preset opening degree threshold value;

and controlling the first electronic expansion valve to operate at the second opening degree, and controlling the second electronic expansion valve to operate at the third opening degree, wherein the third opening degree is greater than the preset opening degree threshold value, and finishing oil return operation.

In an embodiment, the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

judging whether the high pressure of the system is not less than a maximum pressure threshold value;

and if the high pressure of the system is not less than the maximum pressure threshold value, acquiring an initial opening degree of the first electronic expansion valve, and increasing the initial opening degree by a preset value to be used as the second opening degree, wherein the initial opening degree is less than the preset opening degree threshold value.

In an embodiment, the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

if the system high-pressure is smaller than the maximum pressure threshold, judging whether the system high-pressure is not smaller than a minimum pressure threshold;

and if the system high-pressure is not less than the minimum pressure threshold value, taking the initial opening as the second opening.

In an embodiment, the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

and if the high pressure of the system is smaller than the minimum pressure threshold value, reducing the initial opening by a preset value to serve as the second opening.

In an embodiment, the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, and controlling the liquid refrigerant to flow through the first indoor unit heat exchanger and the second indoor unit heat exchanger respectively through a first electronic expansion valve with the opening degree of the second opening degree and a second electronic expansion valve with the opening degree of the third opening degree;

and controlling two paths of refrigerants flowing through the first indoor unit heat exchanger and the second indoor unit heat exchanger to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gaseous refrigerant carrying lubricating oil to flow into the compressor.

In an embodiment, the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, turning down or closing the first electronic expansion valve, and controlling the liquid refrigerant to flow through the second indoor unit heat exchanger through a second electronic expansion valve with the opening degree of the first opening degree;

and controlling two paths of refrigerant flowing through the heat exchanger of the second indoor unit to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gas refrigerant carrying lubricating oil to flow into the compressor.

In an embodiment, the processor 1001 may be configured to call an oil return control program of the multi-split air conditioning system stored in the memory 1005, and perform the following operations:

the method comprises the steps of obtaining the current high-pressure of the multi-split air-conditioning system, reducing or closing the first electronic expansion valve and determining the opening degree corresponding to the second electronic expansion valve based on the current high-pressure, wherein the first opening degree is larger than a preset opening degree threshold value.

According to the scheme, when the opening number of the indoor units is smaller than the preset number threshold and/or the ratio of the opening number of the indoor units to the total number of the indoor units is smaller than the preset ratio threshold, it means that the starting number of the indoor units in the current multi-split air conditioning system is small, the electronic expansion valve of the current starting indoor unit is turned down or closed, and the electronic expansion valve of the current shutdown indoor unit is controlled to operate at the preset opening degree, so that a high-speed circulating refrigerant flows through the indoor unit pipeline which is not currently operated, the oil return operation is ensured, meanwhile, the refrigerant does not pass through the indoor unit pipeline which is currently operated, the influence of noise generated by the oil return operation on a user is reduced, and the user experience is improved.

Based on the hardware framework, the embodiment of the oil return control method of the multi-split air conditioning system is provided.

Referring to fig. 2, fig. 2 is a first embodiment of an oil return control method of a multi-split air conditioning system according to the present invention, where the multi-split air conditioning system includes at least two indoor units, and the oil return control method of the multi-split air conditioning system includes the following steps:

step S10, when an oil return operation instruction is detected, the opening number and the total number of indoor units in the multi-split air conditioning system are obtained;

at present, in a multi-split air conditioning system, the long-time operation of a unit can cause a large amount of lubricating oil of a compressor to be discharged into a system pipeline, so that the compressor is lack of oil. The existing method for solving the problems is to set an oil return operation to make the lubricating oil discharged to the system pipeline return to the compressor, when the unit enters the oil return operation, the frequency of the compressor is increased, the opening of an electronic expansion valve EXV of the indoor unit is increased, the lubricating oil in the system pipeline is flushed back to the gas-liquid separator by using a high-speed flowing liquid refrigerant, and the separated lubricating oil flows back to the compressor through an oil return hole of the gas-liquid separator to finish the oil return operation. However, in the oil return operation of the control unit, the compressor is controlled to increase frequency and the opening of the electronic expansion valve of the indoor unit is increased, so that the flow speed of the system refrigerant is increased, the indoor unit generates large refrigerant flowing sound, the comfort of a user is affected, and the user experience is reduced. The multi-split air conditioning system is characterized in that one outdoor unit is connected with two or more indoor units. The oil return operation is a special operation mode in the multi-split air conditioning unit, and the lubricating oil discharged into a system pipeline returns to the compressor. In order to solve the problems, in the oil return operation, the electronic expansion valve of the indoor unit of the starting room is controlled to be closed, so that the high-speed refrigerant does not pass through the room with the people, and the electronic expansion valve of the closing room is controlled to be opened to a certain opening degree, so that the high-speed refrigerant flows from the room without the people, and therefore, the noise generated in the room with the people due to the oil return operation of the unit is avoided. In the present invention, the execution body is an air conditioner. Specifically, the total number of the indoor units in the multi-split air-conditioning system and the number of the currently opened indoor units of the multi-split air-conditioning system, namely the opening number of the indoor units, are obtained, so that whether the current opening number of the indoor units of the multi-split air-conditioning system is small or not is judged based on the opening number of the indoor units and the total number of the indoor units. When the number of the indoor units is small, namely the system high-pressure of the multi-split air-conditioning system is small, high-speed refrigerants can flow from an unmanned room, and the refrigerants can be prevented from passing through the manned room.

Step S20, when the number of the opened indoor units is smaller than a preset number threshold and/or the ratio of the number of the opened indoor units to the total number of the indoor units is smaller than a preset ratio threshold, determining the current on-state indoor unit and the current off-state indoor unit in the multi-split air-conditioning system;

in this embodiment, when the number of the indoor units turned on is less than a preset number threshold and/or the ratio of the number of the indoor units turned on to the total number of the indoor units is less than a preset ratio threshold, it is indicated whether the current number of the indoor units turned on is small, that is, the system high-pressure of the multi-split air conditioning system is small. And determining the current on-line indoor unit and the current off-line indoor unit in the multi-online air conditioning system. The high-speed refrigerant flows from the unmanned room, so that the high-speed refrigerant does not pass through the manned room or the refrigerant quantity passing through the manned room is reduced, and the influence of refrigerant flowing sound on a user is reduced.

And step S30, turning down or closing the first electronic expansion valve of the currently started indoor unit, and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree to finish oil return operation.

In this embodiment, after determining a currently-started indoor unit and a currently-stopped indoor unit in a multi-split air conditioning system, a first electronic expansion valve of the currently-started indoor unit is turned down or closed. And controlling the second electronic expansion valve of the current shutdown indoor unit to operate at the first opening degree, namely controlling the electronic expansion valve of the current shutdown indoor unit to keep a certain opening degree, and ensuring the high-speed flow of the refrigerant. The electronic expansion valve of the currently started indoor unit is adjusted to be small or closed according to the system high-pressure of the multi-split air-conditioning system, namely, if the electronic expansion valve of the currently shut indoor unit keeps a certain opening degree, the system high-pressure can be kept balanced, namely, the first electronic expansion valve can be closed, and if the electronic expansion valve of the currently shut indoor unit keeps a certain opening degree and the system high-pressure cannot be kept balanced, the opening degree of the first electronic expansion valve is adjusted to be small, so that the first electronic expansion valve is kept at a small opening degree, high-pressure protection of the multi-split air-conditioning system is prevented, and oil return operation is interrupted.

In an embodiment, the step of turning down or closing the first electronic expansion valve of the currently started indoor unit and controlling the second electronic expansion valve of the currently stopped indoor unit to operate at the first opening degree specifically includes:

the method comprises the steps of obtaining the current high-pressure of the multi-split air-conditioning system, reducing or closing the first electronic expansion valve and determining the opening degree corresponding to the second electronic expansion valve based on the current high-pressure, wherein the first opening degree is larger than a preset opening degree threshold value.

In this embodiment, a current high pressure of the multi-split air conditioning system is obtained, and when it is determined that the multi-split air conditioning system can complete the oil return operation through the second electronic expansion valve having a certain opening currently, the first electronic expansion valve is closed, and the opening of the second electronic expansion valve, which enables the multi-split air conditioning system to complete the oil return operation, is set to the first opening. Therefore, the multi-split air conditioning system is ensured to normally perform oil return operation, and meanwhile, noise generated by a room with a person where the indoor unit is started is avoided.

In the technical scheme provided by this embodiment, when the number of the opened indoor units is less than a preset number threshold and/or the ratio of the number of the opened indoor units to the total number of the indoor units is less than a preset ratio threshold, that is, it indicates that the number of the opened indoor units in the current multi-split air conditioning system is small, the electronic expansion valve of the current opened indoor unit is turned down or closed, and the electronic expansion valve of the current closed indoor unit is controlled to operate at a preset opening degree, so that a high-speed circulating refrigerant flows through an indoor unit pipeline which is not currently operated, the oil return operation is ensured, meanwhile, the indoor unit pipeline which is currently operated is not passed through, the influence of noise generated by the oil return operation on a user is reduced, and the user experience is improved.

Referring to fig. 3, fig. 3 is a second embodiment of an oil return control method of a multi-split air conditioning system according to the present invention, and based on the first embodiment, after step S10, the method further includes:

step S40, when the number of the opened indoor units is not less than a preset number threshold and/or the ratio of the number of the opened indoor units to the total number of the indoor units is not less than a ratio threshold, acquiring system high pressure of the multi-split air conditioning system;

step S50, determining a second opening corresponding to the first electronic expansion valve based on the system high pressure, wherein the second opening is smaller than a preset opening threshold;

and step S60, controlling the first electronic expansion valve to operate at the second opening degree, and controlling the second electronic expansion valve to operate at the third opening degree, wherein the third opening degree is greater than the preset opening degree threshold value, and completing oil return operation.

In this embodiment, in order to prevent the multi-split air conditioning system from operating failure due to high-voltage protection, it is first determined whether the number of the indoor units of the multi-split air conditioning system that are turned on is less than a preset number threshold, and/or whether the ratio of the number of the indoor units that are turned on to the total number of the indoor units is less than a ratio threshold. And when the number of the opened indoor units is not less than a preset number threshold value and/or the ratio of the number of the opened indoor units to the total number of the indoor units is not less than a ratio threshold value, the number of the opened indoor units of the current multi-split air-conditioning system is indicated to be more. Therefore, normal oil return operation of the multi-split air conditioner system cannot be guaranteed only by the electronic expansion valve of the shutdown indoor unit. And acquiring the system high pressure P of the multi-split air conditioning system, and then determining the opening degree of the first electronic expansion valve and the opening degree of the second electronic expansion valve based on the system high pressure P. In order to reduce the refrigerant flowing noise of a manned room, the opening degree of the first electronic expansion valve is controlled to be smaller than a preset opening degree threshold value, and the opening degree of the second electronic expansion valve is controlled to be larger than the preset opening degree threshold value. Namely, the second opening degree is smaller than a preset opening degree threshold value, and the third opening degree is larger than the preset opening degree threshold value. The preset opening threshold may be a minimum value or an average value of the opening of the electronic expansion valve for enabling the multi-split air conditioning system to perform oil return operation. The first opening degree and the third opening degree may be equal to or different from each other.

In an embodiment, the step of determining the second opening degree corresponding to the first electronic expansion valve based on the system high pressure specifically includes:

judging whether the high pressure of the system is not less than a maximum pressure threshold value;

and if the high pressure of the system is not less than the maximum pressure threshold value, acquiring an initial opening degree of the first electronic expansion valve, and increasing the initial opening degree by a preset value to be used as the second opening degree, wherein the initial opening degree is less than the preset opening degree threshold value.

If the system high-pressure is smaller than the maximum pressure threshold, judging whether the system high-pressure is not smaller than a minimum pressure threshold;

and if the system high-pressure is not less than the minimum pressure threshold value, taking the initial opening as the second opening.

And if the high pressure of the system is smaller than the minimum pressure threshold value, reducing the initial opening by a preset value to serve as the second opening.

In this embodiment, how to control the first electronic expansion valve of the currently started indoor unit according to the system high-pressure is further detailed. The higher the system high pressure is, the higher the refrigerant flow rate in the pipeline of the corresponding multi-split air conditioning system is. Therefore, the second electronic expansion valve is controlled to keep the maximum opening degree, and the high-speed flow of the refrigerant is ensured. And controlling the first electronic expansion valve to keep an initial opening degree and operate for a preset time, judging whether the high-pressure P of the system is not less than a maximum pressure threshold value a or not if the high-pressure P of the system is not less than a, if the high-pressure P is not less than a, indicating that the opening degree of an electronic expansion valve of an indoor unit of the current multi-split air-conditioning system does not meet the requirement of high-speed flow of a refrigerant, and further increasing the opening degree of the adjustable first electronic expansion valve. Namely, a preset value is increased based on the initial opening degree, for example, 50 steps, so as to increase the flow rate of the refrigerant in the current multi-split air conditioning system. In a specific embodiment, the system high pressure is regularly detected in a preset period, and if the system high pressure in the next period is not less than the maximum pressure threshold, the opening degree of the first electronic expansion valve is further increased based on the increased opening degree until the system high pressure is reduced below the maximum pressure threshold. And if the system high-pressure is smaller than the maximum pressure threshold, further judging whether the system high-pressure is not smaller than a minimum pressure threshold b. If P is less than b, it means that the high pressure of the current system is not enough to make the pipeline refrigerant flow at high speed, and the opening of the electronic expansion valve needs to be reduced to increase the pipeline pressure. That is, the low voltage protection is prevented from occurring based on the initial opening degree decreased by a preset value. In a specific embodiment, the system high pressure is regularly detected in a preset period, and if the system high pressure in the next period is still smaller than the minimum pressure threshold, the opening degree of the first electronic expansion valve is further reduced based on the reduced opening degree until the system high pressure is increased to be higher than the minimum pressure threshold. And if the system high-pressure is not less than the minimum pressure threshold value, the current system high-pressure is appropriate, and the current opening degree of the first electronic expansion valve is maintained, namely the initial opening degree is taken as the second opening degree. Namely:

(1) if P is more than or equal to a, increasing the preset value of the first electronic expansion valve every cycle, such as 50 steps;

(2) b is less than or equal to P and less than a, the first electronic expansion valve is stabilized at the current step number;

(3) and if P is less than b, the first electronic expansion valve is reduced by the preset value every cycle, such as 50 steps.

As shown in fig. 4, in an embodiment, the multi-split air conditioning system includes a compressor, a four-way valve, an outdoor unit heat exchanger, an outdoor unit electronic expansion valve, a first indoor unit heat exchanger, a second indoor unit heat exchanger, and a gas-liquid separator, and the step of controlling the first electronic expansion valve to operate at the second opening degree and controlling the second electronic expansion valve to operate at the third opening degree specifically includes:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, and controlling the liquid refrigerant to flow through the first indoor unit heat exchanger and the second indoor unit heat exchanger respectively through a first electronic expansion valve with the opening degree of the second opening degree and a second electronic expansion valve with the opening degree of the third opening degree;

and controlling two paths of refrigerants flowing through the first indoor unit heat exchanger and the second indoor unit heat exchanger to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gaseous refrigerant carrying lubricating oil to flow into the compressor.

In the present embodiment, 1 is a compressor; 2 is a four-way valve; 3 is an outdoor heat exchanger; 4 is an electronic expansion valve of the outdoor unit; 5 is a first electronic expansion valve; 6 is a first indoor heat exchanger; 7 is a second electronic expansion valve; 8 is a second indoor heat exchanger; 9 is a gas-liquid separator. And controlling the first electronic expansion valve to operate at the second opening degree, and controlling the second electronic expansion valve to operate at the third opening degree, even if the first electronic expansion valve keeps the second opening degree, the second electronic expansion valve keeps the third opening degree. When the number of the started indoor units is not less than a preset number threshold value and/or the ratio of the number of the started indoor units to the total number of the indoor units is not less than a ratio threshold value, namely when the number of the started indoor units is greater than the number threshold value or the ratio of the number of the started indoor units to the total number of the indoor units is greater than a ratio threshold value, namely the number of the started indoor units/the total number of the indoor units is greater than or equal to A, after oil return, the compressor discharges high-temperature and high-pressure gaseous refrigerants and flows to a four-way valve 2 (a four-way valve power-off state); flows to the heat exchanger 3 of the outdoor unit through the four-way valve 2, is condensed and released heat and then is changed into liquid; then divided into two paths by an electronic expansion valve 4, and the two paths respectively pass through a first electronic expansion valve and a second electronic expansion valve and flow into pipelines of the room 1 and the room 2; lubricating oil in gas-liquid two-phase refrigerant flushing pipelines passing through the indoor unit of the room 1 and the indoor unit of the room 2 is collected into one path, and flows into a gas-liquid separator after flowing through the four-way valve 2; the lubricating oil is separated in the liquid separator and flows into the air suction port of the compressor along with the gaseous refrigerant, and then returns to the compressor to finish oil return operation.

In an embodiment, the step of turning down or closing the first electronic expansion valve of the currently turned-on indoor unit and controlling the second electronic expansion valve of the currently turned-off indoor unit to operate at the first opening degree includes:

discharging a gaseous refrigerant through the compressor, controlling the gaseous refrigerant to flow through the four-way valve and the outdoor unit heat exchanger, condensing the gaseous refrigerant and releasing heat to generate a liquid refrigerant;

controlling the liquid refrigerant to flow through the outdoor unit electronic expansion valve, turning down or closing the first electronic expansion valve, and controlling the liquid refrigerant to flow through the second indoor unit heat exchanger through a second electronic expansion valve with the opening degree of the first opening degree;

and controlling two paths of refrigerant flowing through the heat exchanger of the second indoor unit to flow through the four-way valve and enter the gas-liquid separator, and controlling the separated gas refrigerant carrying lubricating oil to flow into the compressor.

In this embodiment, when the number of the opened indoor units/the total number of the indoor units is less than a, the first electronic expansion valve is closed after oil return. The compressor discharges high-temperature and high-pressure gaseous refrigerant, flows to the four-way valve 2 (the four-way valve is in a power-off state), flows to the outdoor heat exchanger 3 through the four-way valve 2, is condensed and releases heat, and then is changed into liquid. If the room 1 is started and the room 2 is shut down, the first electronic expansion valve 5 is closed, the second electronic expansion valve 7 keeps the first opening degree, if the opening degree is adjusted to the opening degree B, the condensed and heat-released liquid refrigerant flows into the pipeline of the room 2 through the second electronic expansion valve 7 with the first opening degree; the refrigerant in gas-liquid two-phase state flushes the lubricating oil in the pipeline of the room 2. In the specific embodiment, if the room 2 is powered on and the room 1 is powered off, the opening of the first electronic expansion valve 5 is adjusted to the opening B, the second electronic expansion valve 7 is closed, and the condensed and heat-released liquid refrigerant flows into the pipeline of the room 1 through the first electronic expansion valve 5; lubricating oil in a pipeline of a flushing room 2 flows into the gas-liquid separator 9 after flowing through the four-way valve 2, the lubricating oil flows into an air suction port of the compressor along with a gaseous refrigerant in the separation of the liquid separator and then returns to the compressor, and oil return operation is completed.

The invention also provides an air conditioner, which comprises a memory, a processor and an oil return control program of the multi-split air conditioning system, wherein the oil return control program is stored in the memory and can run on the processor, and when being executed by the processor, the oil return control program of the multi-split air conditioning system realizes the steps of the oil return control method of the multi-split air conditioning system in the embodiment.

The present invention also provides a computer-readable storage medium, where the computer-readable storage medium includes an oil return control program of a multi-split air conditioning system, and the oil return control program of the multi-split air conditioning system, when executed by a processor, implements the steps of the oil return control method of the multi-split air conditioning system according to the above embodiment.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solution of the present invention may be substantially or partially embodied in the form of a software product, which is stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) as described above and includes instructions for enabling a terminal air conditioner (e.g. a mobile phone, a computer, a server, an air conditioner, or a network air conditioner, etc.) to execute the method according to the embodiments of the present invention.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.