Air conditioner and control method of air conditioner

Abstract

The application discloses an air conditioner and a control method thereof, and the air conditioner comprises: a refrigerant circulation loop; an expansion valve, comprising an electronic expansion valve connected with an outdoor heat exchanger and a thermal expansion valve connected with an indoor heat exchanger; and a controller connected with a pressure sensor and a temperature sensor, wherein the controller is configured to: in a refrigeration mode, receive a stop control instruction, control the four-way valve to be powered on, control the compressor to operate at a frequency lower than a first operating frequency, determine that the operating time length of the compressor reaches a preset time length, acquire a pipeline pressure value and an outdoor environment temperature, determine a saturated refrigerant pressure value according to the outdoor environment temperature, and control the compressor and the outdoor fan to stop operating and control the four-way valve to be powered off after the saturated refrigerant pressure value is consistent with the pipeline pressure value. By using the air conditioner, the problem that the four-way valve pipeline abnormally vibrates and the stress value exceeds the standard due to the fact that the high and low pressure side pressure difference is too large caused by the throttling of the thermal expansion valve can be avoided.

Description

Technical Field

[0001] This invention relates to the field of air conditioner technology, and in particular to an air conditioner and a control method for an air conditioner. Background Technology

[0002] For air conditioners that use thermostatic expansion valves for throttling, the relevant technology uses temperature values ​​collected by a temperature sensor to slowly adjust the opening of the thermostatic expansion valve until the temperature reaches the ambient temperature, at which point the valve opening is at its maximum. However, the adjustment process of the thermostatic expansion valve opening is very slow, and the valve opening remains small even after the air conditioner is turned off. This results in an excessive pressure difference between the high and low pressure sides due to the throttling effect of the thermostatic expansion valve, which in turn leads to abnormal vibration and excessive stress values ​​in the four-way valve pipeline. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide an air conditioner that can avoid excessive pressure difference between the high and low pressure sides caused by throttling of the thermal expansion valve, thereby avoiding the problems of abnormal vibration and excessive stress value in the four-way valve pipeline.

[0004] The second objective of this invention is to provide a control method for an air conditioner.

[0005] To address the aforementioned problems, a first aspect of the present invention provides an air conditioner with a refrigerant circulation loop that circulates the refrigerant within a loop consisting of a compressor, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, and a four-way valve. The expansion valve includes an electronic expansion valve connected to the outdoor heat exchanger and a thermal expansion valve connected to the indoor heat exchanger. An indoor fan drives indoor air to exchange heat with the indoor heat exchanger. An outdoor fan drives outdoor air to exchange heat with the outdoor heat exchanger. A pressure sensor collects the pipeline pressure value of the four-way valve. A temperature sensor collects the outdoor... Ambient temperature; Controller, connected to the pressure sensor and the temperature sensor, configured to: in cooling mode, upon receiving a shutdown control command, control the four-way valve to power on; control the compressor to operate at a frequency lower than a first operating frequency; after determining that the compressor's operating time has reached a preset duration, acquire the pipeline pressure value and the outdoor ambient temperature; determine the saturated refrigerant pressure value based on the outdoor ambient temperature; after determining that the saturated refrigerant pressure value matches the pipeline pressure value, control the compressor and the outdoor fan to stop operating, and control the four-way valve to de-energize.

[0006] According to an embodiment of the present invention, when the air conditioner is shut down in cooling mode, the compressor is controlled to operate at a frequency lower than a first operating frequency. The timing of shutting down the air conditioner is determined by judging whether the saturated refrigerant pressure value is consistent with the pipeline pressure value. If the saturated refrigerant pressure value is consistent with the pipeline pressure value, it indicates that the pressure in the four-way valve pipeline is balanced, and the air conditioner is shut down. This avoids excessive pressure difference between the high and low pressure sides due to throttling of the thermal expansion valve, thereby avoiding abnormal vibration and excessive stress value in the four-way valve pipeline.

[0007] In some embodiments, before energizing the four-way valve, the controller is further configured to: acquire the coil temperature of the outdoor heat exchanger; if it is determined that the coil temperature is higher than a preset temperature value, first control the indoor fan to stop running, and control the outdoor fan to run at a first speed value until the coil temperature is lower than the preset temperature value.

[0008] In some embodiments, for controlling the outdoor fan to operate at a first speed value, the controller is specifically configured to control the outdoor fan to operate at a first speed value higher than the standard speed value.

[0009] In some embodiments, after determining that the coil temperature is greater than a preset temperature value, the controller is further configured to: control the compressor to gradually reduce its operating frequency by a preset amount until the compressor operates at a frequency lower than a first operating frequency.

[0010] In some embodiments, the expansion valve further includes: a fine shut-off valve for controlling the flow of refrigerant between the outdoor heat exchanger and the indoor heat exchanger; and a coarse shut-off valve for controlling the flow of refrigerant between the indoor heat exchanger and the four-way valve.

[0011] A second aspect of the present invention provides a control method for an air conditioner, used in the air conditioner described in the above embodiments. The control method includes: in cooling mode, receiving a shutdown control command and controlling a four-way valve to be energized; controlling the compressor to operate at a frequency lower than a first operating frequency; after determining that the compressor's operating time has reached a preset duration, acquiring the pipeline pressure value of the four-way valve and the outdoor ambient temperature; determining a saturated refrigerant pressure value based on the outdoor ambient temperature; and after determining that the saturated refrigerant pressure value is consistent with the pipeline pressure value, controlling the compressor and the outdoor fan to stop operating, and controlling the four-way valve to be de-energized.

[0012] According to the control method of the air conditioner of the present invention, when the shutdown control is performed in the cooling mode, the compressor is controlled to operate at a frequency lower than the first operating frequency. The timing of the air conditioner shutdown is determined by judging whether the saturated refrigerant pressure value is consistent with the pipeline pressure value. If it is determined that the saturated refrigerant pressure value is consistent with the pipeline pressure value, it indicates that the pressure in the four-way valve pipeline is balanced, and the air conditioner is controlled to shut down. This avoids the problem of excessive pressure difference between the high and low pressure sides due to the throttling of the thermal expansion valve, thereby avoiding the problem of abnormal vibration and excessive stress value in the four-way valve pipeline.

[0013] In some embodiments, before energizing the four-way valve, the control method further includes: acquiring the coil temperature of the outdoor heat exchanger; if it is determined that the coil temperature is higher than a preset temperature value, controlling the indoor fan to stop running first, and controlling the outdoor fan to run at a first speed value until the coil temperature is lower than the preset temperature value.

[0014] In some embodiments, controlling the outdoor fan to operate at a first speed value includes: controlling the outdoor fan to operate at a first speed value higher than a standard speed value.

[0015] In some embodiments, after determining that the coil temperature is greater than a preset temperature value, the control method further includes: controlling the compressor to gradually reduce its operating frequency by a preset amount until the compressor operates at a frequency lower than a first operating frequency.

[0016] In some embodiments, the air conditioner includes: a fine shut-off valve for controlling the flow of refrigerant between an outdoor heat exchanger and an indoor heat exchanger; and a coarse shut-off valve for controlling the flow of refrigerant between the indoor heat exchanger and the four-way valve.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of the circuit connection of an air conditioner according to an embodiment of the present invention;

[0020] Figure 2 This is a structural block diagram of an air conditioner according to an embodiment of the present invention;

[0021] Figure 3 This is a flowchart of a controller control process according to an embodiment of the present invention;

[0022] Figure 4 This is a flowchart of a control method for an air conditioner according to an embodiment of the present invention.

[0023] Figure label:

[0024] Air conditioner 100;

[0025] Compressor 1; Outdoor heat exchanger 2; Expansion valve 3; Indoor heat exchanger 4; Four-way valve 5; Pressure sensor 6; Controller 7; Temperature sensor 8; Electronic expansion valve 31; Thermal expansion valve 32; Fine shut-off valve 33; Coarse shut-off valve 34. Detailed Implementation

[0026] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0027] To address the aforementioned problems, the first aspect of this invention provides an air conditioner that avoids excessive pressure difference between high and low pressure sides caused by throttling of the thermal expansion valve, thereby preventing abnormal vibration and excessive stress values ​​in the four-way valve pipeline.

[0028] The following is for reference. Figure 1 An air conditioner according to an embodiment of the present invention is described, the air conditioner comprising: a refrigerant circulation loop, an expansion valve, an indoor fan, an outdoor fan, a pressure sensor, a temperature sensor, and a controller.

[0029] The refrigerant circulation loop circulates the refrigerant within a circuit consisting of compressor 1, outdoor heat exchanger 2, expansion valve 3, indoor heat exchanger 4, and four-way valve 5. Expansion valve 3 includes an electronic expansion valve 31 connected to the outdoor heat exchanger 2 and a thermal expansion valve connected to the indoor heat exchanger. An indoor fan drives indoor air to exchange heat with the indoor heat exchanger. An outdoor fan drives outdoor air to exchange heat with the outdoor heat exchanger. A pressure sensor collects the pipeline pressure value of the four-way valve. A temperature sensor collects the outdoor ambient temperature. Figure 2 As shown, controller 7 is connected to pressure sensor 6 and temperature sensor 8.

[0030] Controller 7 is configured to control the air conditioner to stop by performing the following operations.

[0031] In cooling mode, upon receiving a shutdown control command, the four-way valve is powered on.

[0032] Specifically, when the air conditioner is in cooling mode, if the user wants to control the air conditioner to stop, they can send a stop control command to the air conditioner through the remote control, the air conditioner application on the mobile terminal, or the control panel on the air conditioner body, using voice, gestures, or other operation methods. The air conditioner controller receives the stop control command and controls the four-way valve to power on.

[0033] Control the compressor to operate at a frequency lower than the first operating frequency.

[0034] Specifically, in air conditioners using thermostatic expansion valves for throttling, the opening of the thermostatic expansion valve is slowly adjusted by collecting temperature values ​​from a temperature sensor until the temperature reaches the ambient temperature, at which point the valve opening is at its maximum. However, the adjustment process is very slow, and the valve opening remains small even after the air conditioner stops. This results in a large pressure difference between the high and low pressure sides due to the throttling, leading to abnormal vibration and excessive stress in the four-way valve piping. To address this issue, this application controls the compressor to operate at a frequency lower than the first operating frequency, allowing the refrigerant to flow slowly within the refrigerant circulation loop. This increases the pressure in the four-way valve piping, reducing the pressure difference between the high and low pressure sides and enabling the system pressure to quickly reach equilibrium. This avoids excessive pressure differences between the high and low pressure sides caused by the throttling of the thermostatic expansion valve, thus preventing abnormal vibration and excessive stress in the four-way valve piping.

[0035] Once the compressor has been running for the preset duration, obtain the pipeline pressure value and the outdoor ambient temperature.

[0036] Specifically, after the controller determines that the compressor has run for a preset period of time, that is, after the compressor has run stably, it acquires the pipeline pressure value of the four-way valve collected by the pressure sensor and the outdoor ambient temperature collected by the temperature sensor to ensure that the pipeline pressure value and the outdoor ambient temperature are accurately acquired.

[0037] The saturated refrigerant pressure value is determined based on the outdoor ambient temperature.

[0038] The saturated refrigerant pressure value is the refrigerant pressure value corresponding to the pressure balance in the pipes when the air conditioner is stationary.

[0039] Specifically, the saturated refrigerant pressure value is determined based on the outdoor ambient temperature. That is, a table of correspondence between outdoor ambient temperature and saturated refrigerant pressure value is pre-stored in the controller. Thus, the saturated refrigerant pressure value corresponding to the outdoor ambient temperature can be found in the controller.

[0040] Once it is confirmed that the saturated refrigerant pressure value matches the pipeline pressure value, the compressor and outdoor fan will be stopped, and the four-way valve will be de-energized.

[0041] Specifically, in related technologies for air conditioners using thermostatic expansion valves for throttling, the opening of the thermostatic expansion valve is slowly adjusted based on the temperature value collected by the temperature sensor until the temperature reaches the ambient temperature, at which point the opening of the thermostatic expansion valve is at its maximum. However, the adjustment process of the thermostatic expansion valve opening is very slow, and the opening of the thermostatic expansion valve remains small even after the air conditioner is turned off. This results in an excessively large pressure difference between the high and low pressure sides due to the throttling of the thermostatic expansion valve, leading to abnormal vibration and excessive stress values ​​in the four-way valve pipeline. To solve this problem, this application controls the compressor to operate at a frequency lower than the first operating frequency, so that the refrigerant flows slowly in the refrigerant circulation loop. The system moves to increase the pressure value of the four-way valve in the pipeline, thereby reducing the pressure difference between the high and low pressure sides and enabling the system pressure to reach a rapid balance. Then, by judging whether the saturated refrigerant pressure value is consistent with the pipeline pressure value, the timing of controlling the shutdown of the air conditioner is determined. If it is determined that the saturated refrigerant pressure value is consistent with the pipeline pressure value, it means that the pressure in the four-way valve pipeline is balanced, that is, there is no pressure difference between the high and low pressure sides. At this time, the compressor and outdoor fan are stopped, and the power to the four-way valve is cut off, thus completing the shutdown control of the air conditioner. This avoids the problem of excessive pressure difference between the high and low pressure sides due to throttling of the thermal expansion valve, and thus avoids the problems of abnormal vibration and excessive stress value in the four-way valve pipeline.

[0042] According to an embodiment of the present invention, when the air conditioner is shut down in cooling mode, the compressor is controlled to operate at a frequency lower than a first operating frequency. The timing of shutting down the air conditioner is determined by judging whether the saturated refrigerant pressure value is consistent with the pipeline pressure value. If the saturated refrigerant pressure value is consistent with the pipeline pressure value, it indicates that the pressure in the four-way valve pipeline is balanced, and the air conditioner is shut down. This avoids excessive pressure difference between the high and low pressure sides due to throttling of the thermal expansion valve, thereby avoiding abnormal vibration and excessive stress value in the four-way valve pipeline.

[0043] In some embodiments, before energizing the four-way valve, such as Figure 3 As shown, the controller is also configured to perform the following steps.

[0044] Step S6: Obtain the coil temperature of the outdoor heat exchanger.

[0045] Step S7: If it is determined that the coil temperature is higher than the preset temperature value, the indoor fan is stopped and the outdoor fan is operated at the first speed value until the coil temperature is lower than the preset temperature value.

[0046] Specifically, to avoid damage to the four-way valve due to excessive pressure difference between the high and low pressure sides, after the air conditioner detects a shutdown control command during cooling mode, a temperature sensor installed on the outdoor heat exchanger collects the coil temperature of the outdoor heat exchanger, for example, denoted as T1, and transmits the collected coil temperature T1 to the controller. Upon receiving the outdoor heat exchanger coil temperature T1, the controller determines whether T1 is higher than a preset temperature value, where the preset temperature value can be understood as based on the four-way valve's operating temperature at high temperatures. If the pressure difference between the valve and the preset temperature value is too large, it indicates that the coil temperature of the outdoor heat exchanger is too high, resulting in an excessive pressure difference between the high and low pressure sides, which in turn damages the four-way valve. In this case, the indoor fan should be stopped to stop driving the indoor air to exchange heat with the indoor heat exchanger, and the outdoor fan should be controlled to run at the first speed value to reduce the coil temperature of the outdoor heat exchanger until the coil temperature is lower than the preset temperature value, thereby avoiding damage to the four-way valve due to the excessive pressure difference between the high and low pressure sides.

[0047] In some embodiments, for controlling the outdoor fan to operate at a first speed value, the controller is specifically configured to: control the outdoor fan to operate at a first speed value higher than the standard speed value. That is, by controlling the outdoor fan to operate at a first speed value higher than the standard speed value, i.e., by increasing the speed of the outdoor fan, the heat generated by the air conditioner in cooling mode is dissipated quickly, thereby rapidly reducing the coil temperature of the outdoor heat exchanger. This avoids the problem of damage to the four-way valve due to excessive pressure difference between the high and low pressure sides. For example, the first speed value can be the maximum speed value of the outdoor fan, thus controlling the outdoor fan to operate at the maximum speed value, so that the heat generated by the air conditioner in cooling mode is dissipated quickly until the coil temperature is lower than the preset temperature value, thereby avoiding the problem of damage to the four-way valve due to excessive pressure difference between the high and low pressure sides.

[0048] In some embodiments, after determining that the coil temperature is greater than a preset temperature value, the controller is further configured to: control the compressor to gradually reduce its operating frequency by a preset margin until the compressor operates at a frequency lower than a first operating frequency. That is, to avoid damage to the four-way valve due to excessive pressure difference between the high and low pressure sides, after the air conditioner detects a shutdown control command during cooling mode operation, a temperature sensor installed on the outdoor heat exchanger collects the coil temperature of the outdoor heat exchanger and transmits the collected coil temperature T1 to the controller. Upon receiving the outdoor heat exchanger coil temperature T1 and determining that it is higher than a preset temperature value, the controller controls the compressor to gradually reduce its operating frequency by a preset margin until the compressor operates at a frequency lower than the first operating frequency. This reduces the heat dissipation of the outdoor heat exchanger by lowering the compressor frequency, thereby reducing the coil temperature of the outdoor heat exchanger and preventing damage to the four-way valve due to excessive pressure difference between the high and low pressure sides.

[0049] In some embodiments, such as Figure 1 The expansion valve 3 further includes a fine shut-off valve 33 and a coarse shut-off valve 34.

[0050] The fine shut-off valve controls the refrigerant flow between the outdoor and indoor heat exchangers; the coarse shut-off valve controls the refrigerant flow between the indoor heat exchanger and the four-way valve. In other words, in cooling mode, the fine shut-off valve controls the refrigerant flow path between the outdoor and indoor heat exchangers, thus controlling the refrigerant flow from the outdoor heat exchanger to the indoor heat exchanger, or it can cut off the refrigerant flow path between them. Furthermore, the fine shut-off valve can regulate the refrigerant flow between the outdoor and indoor heat exchangers. Similarly, the coarse shut-off valve controls the refrigerant flow path between the indoor heat exchanger and the four-way valve, thus controlling the refrigerant flow from the indoor heat exchanger to the four-way valve, or it can cut off the refrigerant flow path between them. Additionally, the coarse shut-off valve can regulate the refrigerant flow between the indoor heat exchanger and the four-way valve.

[0051] A second aspect of the present invention provides a control method for an air conditioner, used in the air conditioner described in the above embodiments, such as... Figure 4 As shown, the control methods include:

[0052] Step S1: In cooling mode, upon receiving a shutdown control command, the four-way valve is powered on.

[0053] Specifically, when the air conditioner is in cooling mode, if the user wants to control the air conditioner to stop, they can send a stop control command to the air conditioner through the remote control, the air conditioner application on the mobile terminal, or the control panel on the air conditioner body, using voice, gestures, or other operation methods. The air conditioner controller receives the stop control command and controls the four-way valve to power on.

[0054] Step S2: Control the compressor to operate at a frequency lower than the first operating frequency.

[0055] Specifically, in air conditioners using thermostatic expansion valves for throttling, the opening of the thermostatic expansion valve is slowly adjusted by collecting temperature values ​​from a temperature sensor until the temperature reaches the ambient temperature, at which point the valve opening is at its maximum. However, the adjustment process is very slow, and the valve opening remains small even after the air conditioner stops. This results in a large pressure difference between the high and low pressure sides due to the throttling, leading to abnormal vibration and excessive stress in the four-way valve piping. To address this issue, this application controls the compressor to operate at a frequency lower than the first operating frequency, allowing the refrigerant to flow slowly within the refrigerant circulation loop. This increases the pressure in the four-way valve piping, reducing the pressure difference between the high and low pressure sides and enabling the system pressure to quickly reach equilibrium. This avoids excessive pressure differences between the high and low pressure sides caused by the throttling of the thermostatic expansion valve, thus preventing abnormal vibration and excessive stress in the four-way valve piping.

[0056] Step S3: After determining that the compressor has run for a preset time, obtain the pipeline pressure value of the four-way valve and the outdoor ambient temperature.

[0057] Specifically, after the controller determines that the compressor has run for a preset period of time, that is, after the compressor has run stably, it acquires the pipeline pressure value of the four-way valve collected by the pressure sensor and the outdoor ambient temperature collected by the temperature sensor to ensure that the pipeline pressure value and the outdoor ambient temperature are accurately acquired.

[0058] Step S4: Determine the saturated refrigerant pressure value based on the outdoor ambient temperature.

[0059] Specifically, the saturated refrigerant pressure value is determined based on the outdoor ambient temperature. That is, a table of correspondence between outdoor ambient temperature and saturated refrigerant pressure value is pre-stored in the controller. Thus, the saturated refrigerant pressure value corresponding to the outdoor ambient temperature can be found in the controller.

[0060] Step S5: After confirming that the saturated refrigerant pressure value is consistent with the pipeline pressure value, control the compressor and outdoor fan to stop running, and control the four-way valve to cut off power.

[0061] Specifically, in related technologies for air conditioners using thermostatic expansion valves for throttling, the opening of the thermostatic expansion valve is slowly adjusted based on the temperature value collected by the temperature sensor until the temperature reaches the ambient temperature, at which point the opening of the thermostatic expansion valve is at its maximum. However, the adjustment process of the thermostatic expansion valve opening is very slow, and the opening of the thermostatic expansion valve remains small even after the air conditioner is turned off. This results in an excessively large pressure difference between the high and low pressure sides due to the throttling of the thermostatic expansion valve, leading to abnormal vibration and excessive stress values ​​in the four-way valve pipeline. To solve this problem, this application controls the compressor to operate at a frequency lower than the first operating frequency, so that the refrigerant flows slowly in the refrigerant circulation loop. The system moves to increase the pressure value of the four-way valve in the pipeline, thereby reducing the pressure difference between the high and low pressure sides and enabling the system pressure to reach a rapid balance. Then, by judging whether the saturated refrigerant pressure value is consistent with the pipeline pressure value, the timing of controlling the shutdown of the air conditioner is determined. If it is determined that the saturated refrigerant pressure value is consistent with the pipeline pressure value, it means that the pressure in the four-way valve pipeline is balanced, that is, there is no pressure difference between the high and low pressure sides. At this time, the compressor and outdoor fan are stopped, and the power to the four-way valve is cut off, thus completing the shutdown control of the air conditioner. This avoids the problem of excessive pressure difference between the high and low pressure sides due to throttling of the thermal expansion valve, and thus avoids the problems of abnormal vibration and excessive stress value in the four-way valve pipeline.

[0062] According to the control method of the air conditioner of the present invention, when the shutdown control is performed in the cooling mode, the compressor is controlled to operate at a frequency lower than the first operating frequency. The timing of the air conditioner shutdown is determined by judging whether the saturated refrigerant pressure value is consistent with the pipeline pressure value. If it is determined that the saturated refrigerant pressure value is consistent with the pipeline pressure value, it indicates that the pressure in the four-way valve pipeline is balanced, and the air conditioner is controlled to shut down. This avoids the problem of excessive pressure difference between the high and low pressure sides due to the throttling of the thermal expansion valve, thereby avoiding the problem of abnormal vibration and excessive stress value in the four-way valve pipeline.

[0063] In some embodiments, before energizing the four-way valve, the control method further includes: acquiring the coil temperature of the outdoor heat exchanger; if it is determined that the coil temperature is higher than a preset temperature value, controlling the indoor fan to stop operating first, and controlling the outdoor fan to operate at a first speed value until the coil temperature is lower than the preset temperature value.

[0064] Specifically, to avoid damage to the four-way valve due to excessive pressure difference between the high and low pressure sides, after detecting a shutdown control command during cooling mode, the air conditioner uses a temperature sensor installed on the outdoor heat exchanger to collect the coil temperature of the outdoor heat exchanger. This outdoor heat exchanger coil temperature is recorded as T1, and the collected temperature is transmitted to the controller. Upon receiving the outdoor heat exchanger coil temperature T1, the controller determines whether it exceeds a preset temperature value. This preset temperature value can be understood as the threshold value set based on the condition that excessive pressure difference in the four-way valve at high temperatures... If the preset temperature value causes damage to the four-way valve, and the coil temperature is found to be higher than the preset temperature value, it indicates that the outdoor heat exchanger coil temperature is too high, resulting in an excessive pressure difference between the high and low pressure sides, which in turn leads to the damage of the four-way valve. In this case, the indoor fan is first controlled to stop running, that is, the indoor fan is controlled to stop driving indoor air to exchange heat with the indoor heat exchanger, and the outdoor fan is controlled to run at the first speed value to reduce the coil temperature of the outdoor heat exchanger until the coil temperature is lower than the preset temperature value. This avoids the problem of the four-way valve being damaged due to excessive pressure difference between the high and low pressure sides, thus improving the reliability of the air conditioner.

[0065] In some embodiments, controlling the outdoor fan to operate at a first speed value includes: controlling the outdoor fan to operate at a first speed value higher than the standard speed value. That is, by controlling the outdoor fan to operate at a first speed value higher than the standard speed value, i.e., by increasing the speed of the outdoor fan, the heat generated by the air conditioner in cooling mode is dissipated quickly, thereby rapidly reducing the coil temperature of the outdoor heat exchanger. This avoids the problem of damage to the four-way valve due to excessive pressure difference between the high and low pressure sides. For example, the first speed value can be the maximum speed value of the outdoor fan, thus controlling the outdoor fan to operate at the maximum speed value allows the heat generated by the air conditioner in cooling mode to dissipate quickly until the coil temperature is lower than the preset temperature value, thereby avoiding the problem of damage to the four-way valve due to excessive pressure difference between the high and low pressure sides.

[0066] In some embodiments, after determining that the coil temperature is greater than a preset temperature value, the control method further includes: controlling the compressor to gradually reduce its operating frequency by a preset margin until the compressor operates at a frequency lower than a first operating frequency. That is, to avoid damage to the four-way valve due to excessive pressure difference between the high and low pressure sides, after the air conditioner detects a shutdown control command during cooling mode operation, a temperature sensor installed on the outdoor heat exchanger collects the coil temperature of the outdoor heat exchanger and transmits the collected coil temperature T1 to the controller. Upon receiving the outdoor heat exchanger coil temperature T1 and determining that it is higher than a preset temperature value, the controller controls the compressor to gradually reduce its operating frequency by a preset margin until the compressor operates at a frequency lower than the first operating frequency. This reduces the heat dissipation of the outdoor heat exchanger by lowering the compressor frequency, thereby reducing the coil temperature of the outdoor heat exchanger and preventing damage to the four-way valve due to excessive pressure difference between the high and low pressure sides.

[0067] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0068] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that, include: The refrigerant circulation loop allows the refrigerant to circulate within a loop consisting of the compressor, outdoor heat exchanger, expansion valve, indoor heat exchanger, and four-way valve. The expansion valve includes an electronic expansion valve connected to the outdoor heat exchanger and a thermal expansion valve connected to the indoor heat exchanger. An indoor fan is used to drive indoor air to exchange heat with the indoor heat exchanger. An outdoor fan is used to drive outdoor air to exchange heat with the outdoor heat exchanger. A pressure sensor is used to collect the pipeline pressure value of the four-way valve; Temperature sensor used to collect outdoor ambient temperature; The controller, connected to the pressure sensor and the temperature sensor, is configured to: In cooling mode, upon receiving a shutdown control command, the four-way valve is energized. Control the compressor to operate at a frequency lower than the first operating frequency; After determining that the compressor has run for a preset period of time, the pipeline pressure value and the outdoor ambient temperature are obtained. Determine the saturated refrigerant pressure value based on the outdoor ambient temperature; After confirming that the saturated refrigerant pressure value is consistent with the pipeline pressure value, the compressor and the outdoor fan are stopped, and the four-way valve is de-energized.

2. The air conditioner according to claim 1, characterized in that, Before energizing the four-way valve, the controller is also configured to: Obtain the coil temperature of the outdoor heat exchanger; If the coil temperature is determined to be higher than the preset temperature value, the indoor fan is first controlled to stop running, and the outdoor fan is controlled to run at a first speed value until the coil temperature is lower than the preset temperature value.

3. The air conditioner according to claim 2, characterized in that, For the purpose of controlling the outdoor fan to operate at a first speed value, the controller is specifically configured as follows: The outdoor fan is controlled to operate at a first speed value higher than the standard speed value.

4. The air conditioner according to claim 2, characterized in that, After determining that the coil temperature is greater than a preset temperature value, the controller is further configured to: The compressor is controlled to gradually reduce its operating frequency by a preset amount until it operates at a frequency lower than the first operating frequency.

5. The air conditioner according to any one of claims 1-4, characterized in that, The expansion valve also includes: A fine shut-off valve, which is used to control the flow of refrigerant between the outdoor heat exchanger and the indoor heat exchanger; A coarse shut-off valve is used to control the flow of refrigerant between the indoor heat exchanger and the four-way valve.

6. A control method for an air conditioner, characterized in that, For an air conditioner according to any one of claims 1-5, the control method includes: In cooling mode, upon receiving a shutdown control command, the four-way valve is powered on. Control the compressor to operate at a frequency lower than the first operating frequency; After determining that the compressor has run for a preset period of time, the pipeline pressure value of the four-way valve and the outdoor ambient temperature are obtained. Determine the saturated refrigerant pressure value based on the outdoor ambient temperature; After confirming that the saturated refrigerant pressure value is consistent with the pipeline pressure value, the compressor and outdoor fan are stopped, and the four-way valve is de-energized.

7. The control method for an air conditioner according to claim 6, characterized in that, Before energizing the four-way valve, the control method further includes: Obtain the coil temperature of the outdoor heat exchanger; If the coil temperature is determined to be higher than the preset temperature value, the indoor fan is first controlled to stop running, and the outdoor fan is controlled to run at a first speed value until the coil temperature is lower than the preset temperature value.

8. The control method for an air conditioner according to claim 7, characterized in that, Controlling the outdoor fan to operate at a first speed value includes: The outdoor fan is controlled to operate at a first speed value higher than the standard speed value.

9. The control method for an air conditioner according to claim 7, characterized in that, After determining that the coil temperature is greater than a preset temperature value, the control method further includes: The compressor is controlled to gradually reduce its operating frequency by a preset amount until it operates at a frequency lower than the first operating frequency.

10. The control method for an air conditioner according to any one of claims 6-9, characterized in that, The air conditioner includes: A fine shut-off valve, which is used to control the flow of refrigerant between the outdoor heat exchanger and the indoor heat exchanger; A coarse shut-off valve is used to control the flow of refrigerant between the indoor heat exchanger and the four-way valve.

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