Air conditioning unit and control method thereof

Abstract

The present invention discloses an air conditioning unit and a control method thereof, wherein the air conditioning unit comprises: a compressor, a four-way valve, a first outdoor heat exchanger, a first outdoor electronic expansion valve, an indoor heat exchanger and a gas-liquid separator connected in sequence; a second outdoor heat exchanger, comprising a first port, a second port, a third port and a fourth port; wherein the first port is connected to the third port, and the second port is connected to the fourth port; the first port is connected to the indoor heat exchanger, the third port is connected to the outdoor electronic expansion valve, the second port is connected to a first connection point between the third port and the first outdoor electronic expansion valve, and the fourth port is connected to an inlet of the gas-liquid separator; the exhaust port of the compressor is also connected to a second connection point between the first port and the indoor heat exchanger. The present invention solves the problem of high noise caused by the operation mode conversion after the defrosting of the air conditioning unit in the prior art, effectively reduces the noise, and improves the comfort and experience of the user.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an air conditioning unit and a control method thereof. Background Art

[0002] In the prior art, air conditioner units are prone to frost when operating in heating mode. Therefore, defrosting is often performed by switching from heating mode to cooling mode. After defrosting is completed, the unit is switched to heating mode. However, when switching to heating mode after defrosting is completed, the four-way valve (2) switches direction under high pressure difference conditions, and the airflow noise of the switching will be transmitted to the indoor side along with the refrigerant. At the same time, the collision sound between the high-pressure airflow and the liquid fluid in the inner pipe during the switching increases the indoor noise.

[0003] With regard to the problem of high noise caused by the switching of operating modes after defrosting of the air-conditioning unit in the related art, no effective solution has been proposed so far. Summary of the invention

[0004] The present invention provides an air conditioning unit and a control method thereof, so as to at least solve the problem of high noise caused by operation mode switching after defrosting of the air conditioning unit in the prior art.

[0005] To solve the above technical problems, according to one aspect of an embodiment of the present invention, an air-conditioning unit is provided, comprising: a compressor, a four-way valve, a first outdoor heat exchanger, a first outdoor electronic expansion valve, an indoor heat exchanger and a gas-liquid separator connected in sequence; a second outdoor heat exchanger, comprising a first port, a second port, a third port and a fourth port; wherein the first port is connected to the third port, and the second port is connected to the fourth port; the first port is connected to the indoor heat exchanger, the third port is connected to the outdoor electronic expansion valve, the second port is connected to a first connection point between the third port and the first outdoor electronic expansion valve, and the fourth port is connected to the inlet of the gas-liquid separator; the exhaust port of the compressor is also connected to the second connection point between the first port and the indoor heat exchanger.

[0006] Furthermore, it also includes: a first switch valve, which is located on the pipeline between the exhaust port of the compressor and the second connection point.

[0007] Furthermore, the D port of the four-way valve is connected to the exhaust port of the compressor, the C port of the four-way valve is connected to the first outdoor heat exchanger, the S port of the four-way valve is connected to the third connection point between the fourth port and the inlet of the gas-liquid separator, and the E port of the four-way valve is connected to the indoor heat exchanger; the air-conditioning unit also includes: a second switch valve, located on the pipeline between the S port of the four-way valve and the third connection point.

[0008] Furthermore, it also includes: a second outdoor electronic expansion valve, located on the pipeline between the third port and the first connection point; a third switch valve, one end of which is connected to a fourth connection point between the second switch valve and the S port of the four-way valve, and the other end is connected to a fifth connection point between the third port and the second outdoor electronic expansion valve.

[0009] Furthermore, it also includes: a fourth switch valve, located on the pipeline between the indoor heat exchanger and the second connection point; an indoor electronic expansion valve, one end of which is connected to the indoor heat exchanger, and the other end of which is connected to the fourth switch valve.

[0010] Furthermore, it also includes: a fifth switch valve, which is located on the pipeline between the E port of the four-way valve and the indoor heat exchanger.

[0011] According to another aspect of an embodiment of the present invention, a method for controlling an air-conditioning unit is provided, which is applied to an air-conditioning unit as described above, and the method includes: after the air-conditioning unit enters a defrost mode, detecting whether the air-conditioning unit satisfies a defrost exit condition; if the defrost exit condition is satisfied, controlling the air-conditioning unit to enter an outdoor self-circulation mode, so that the refrigerant of the outdoor unit exchanges heat in a refrigerant circulation pipeline composed of a first outdoor heat exchanger, a second outdoor heat exchanger and a compressor.

[0012] Further, the air-conditioning unit is controlled to enter the outdoor self-circulation mode, including: controlling the S port of the four-way valve to connect with the C port, connecting the D port of the four-way valve with the E port, controlling the second switch valve, the fourth switch valve and the fifth switch valve to disconnect, and controlling the first switch valve and the third switch valve to close.

[0013] Furthermore, after controlling the air-conditioning unit to enter the outdoor self-circulation mode, it also includes: detecting the ratio of the exhaust pressure and the suction pressure of the compressor; when the ratio is less than a preset threshold, controlling the air-conditioning unit to enter the heating mode.

[0014] Furthermore, before the air-conditioning unit runs the defrost mode, it also includes: controlling the air-conditioning unit to enter the heating mode; after the air-conditioning unit enters the heating mode, detecting whether the air-conditioning unit meets the defrost entry conditions; if the defrost entry conditions are met, controlling the air-conditioning unit to enter the defrost mode.

[0015] Further, controlling the air-conditioning unit to enter the heating mode includes: controlling the S port of the four-way valve to be connected to the C port, the D port of the four-way valve to be connected to the E port, controlling the second switch valve, the fourth switch valve and the fifth switch valve to be closed, and controlling the first switch valve and the third switch valve to be disconnected; controlling the air-conditioning unit to enter the defrost mode includes: controlling the S port of the four-way valve to be connected to the E port, the D port of the four-way valve to be connected to the C port, controlling the second switch valve, the fourth switch valve and the fifth switch valve to be closed, and controlling the first switch valve and the third switch valve to be disconnected.

[0016] According to another aspect of an embodiment of the present invention, there is provided a storage medium comprising computer executable instructions, wherein the computer executable instructions are used to execute the air conditioning unit control method as described above when executed by a computer processor.

[0017] In the present invention, an air-conditioning unit that can effectively reduce noise is provided, and the unit includes a first outdoor heat exchanger and a second outdoor heat exchanger, and the second outdoor heat exchanger is respectively connected to the exhaust port of an outdoor electronic expansion valve, a gas-liquid separator and a compressor, and is used for entering an outdoor self-circulation mode after exiting defrosting, so that the refrigerant of the outdoor unit exchanges heat in a refrigerant circulation pipeline composed of the first outdoor heat exchanger, the second outdoor heat exchanger and the compressor, thereby avoiding the problem of large indoor noise caused by the reversing airflow noise when the operating mode is switched after the air-conditioning unit is defrosted, and the impact sound between the high-pressure airflow and the liquid fluid in the inner pipeline, thereby effectively reducing the noise of the indoor unit when the operating mode is switched after the air-conditioning unit is defrosted, and improving the user's comfort and experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of an optional structure of an air conditioning unit according to an embodiment of the present invention;

[0019] Figure 2 is a refrigerant flow diagram in a heating mode of an air-conditioning unit according to an embodiment of the present invention;

[0020] Figure 3 is a refrigerant flow diagram of a cooling mode of an air-conditioning unit according to an embodiment of the present invention;

[0021] Figure 4 is a refrigerant flow diagram of an outdoor self-circulation mode of an air-conditioning unit according to an embodiment of the present invention;

[0022] Figure 5 is an optional flow chart of an air conditioning unit control method according to an embodiment of the present invention; and

[0023] Figure 6 is another optional flow chart of the air conditioning unit control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0025] Example 1

[0026] In a preferred embodiment 1 of the present invention, an air conditioning unit is provided. Specifically, Figure 1 An optional structural diagram of the air conditioning unit is shown, such as Figure 1 As shown, the unit includes:

[0027] A compressor 1, a four-way valve 2, a first outdoor heat exchanger 3, a first outdoor electronic expansion valve 4, an indoor heat exchanger 5 and a gas-liquid separator 6 connected in sequence;

[0028] The second outdoor heat exchanger 7 includes a first port 71, a second port 72, a third port 73 and a fourth port 74; wherein the first port 71 is connected to the third port 73, and the second port 72 is connected to the fourth port 74; the first port 71 is connected to the indoor heat exchanger 5, the third port 73 is connected to the outdoor electronic expansion valve, the second port 72 is connected to the first connection point between the third port 73 and the first outdoor electronic expansion valve 4, and the fourth port 74 is connected to the inlet of the gas-liquid separator 6;

[0029] The exhaust port of the compressor 1 is also connected to the second connection point between the first port 71 and the indoor heat exchanger 5. In this way, the air conditioning unit constitutes an outdoor self-circulation system, including the first outdoor heat exchanger 3 and the second outdoor heat exchanger 7, the outdoor electronic expansion valve, the gas-liquid separator 6 and the compressor 1, as well as related switch valves and other components. After exiting the defrosting mode, it enters the outdoor self-circulation mode, and the refrigerant self-circulates outdoors, avoiding the problem of large indoor noise caused by the switching of the operating mode after the air conditioning unit defrosts.

[0030] In the above embodiment, an air conditioning unit that can effectively reduce noise is provided, the unit includes a first outdoor heat exchanger 3 and a second outdoor heat exchanger 7, the second outdoor heat exchanger 7 is respectively connected to the outdoor electronic expansion valve, the gas-liquid separator 6 and the exhaust port of the compressor 1, and is used to enter the outdoor self-circulation mode after exiting defrosting, so that the refrigerant of the outdoor unit is heat exchanged in the refrigerant circulation pipeline composed of the first outdoor heat exchanger 3, the second outdoor heat exchanger 7 and the compressor 1, avoiding the problem of large indoor noise caused by the reversing airflow noise and the collision sound between the high-pressure airflow and the liquid fluid in the inner pipeline when the operating mode is switched after the defrosting of the air conditioning unit is completed, effectively reducing the noise of the indoor unit when the operating mode is switched after the defrosting of the air conditioning unit is completed, and improving the user's comfort and experience. Further, it also includes: a first switch valve 8, located on the pipeline between the exhaust port of the compressor 1 and the second connection point. The first switch valve 8 can control the on-off of the pipeline between the exhaust port of the compressor 1 and the second connection point, and the pipeline is turned on when the outdoor unit is self-circulating.

[0031] like Figure 1As shown, the D port of the four-way valve 2 is connected to the exhaust port of the compressor 1, the C port of the four-way valve 2 is connected to the first outdoor heat exchanger 3, the S port of the four-way valve 2 is connected to the third connection point between the fourth port 74 and the inlet of the gas-liquid separator 6, and the E port of the four-way valve 2 is connected to the indoor heat exchanger 5; the air conditioning unit also includes: a second switch valve 9, which is located on the pipeline between the S port of the four-way valve 2 and the third connection point. The second switch valve 9 can control the flow direction of the refrigerant coming out of the S port of the four-way valve 2. When the second switch valve 9 is turned on, the refrigerant coming out of the S port directly enters the gas-liquid separator 6, which is consistent with the conventional heat exchange mode. When the second switch valve 9 is disconnected, the refrigerant coming out of the S port enters the third switch valve 11, one end of the third switch valve 11 is connected to the fourth connection point between the second switch valve 9 and the S port of the four-way valve 2, and the other end is connected to the fifth connection point between the third port 73 and the second outdoor electronic expansion valve 10; the second outdoor electronic expansion valve 10 is located on the pipeline between the third port 73 and the first connection point.

[0032] In addition, the air conditioning unit further includes: a fourth switch valve 12, located on the pipeline between the indoor heat exchanger 5 and the second connection point; an indoor electronic expansion valve 13, one end of which is connected to the indoor heat exchanger 5, and the other end of which is connected to the fourth switch valve 12. And, a fifth switch valve 14, located on the pipeline between the E port of the four-way valve 2 and the indoor heat exchanger 5.

[0033] The heating mode, the cooling and defrosting mode and the outdoor self-circulation mode of the air-conditioning unit can be realized by controlling the switch valve and the four-way valve 2.

[0034] Figure 2 The refrigerant flow diagram of the heating mode of the air conditioning unit is shown as Figure 2 As shown, the S port of the four-way valve 2 is connected to the C port, the D port of the four-way valve 2 is connected to the E port, the second switch valve 9, the fourth switch valve 12 and the fifth switch valve 14 are closed, and the first switch valve 8 and the third switch valve 11 are disconnected. The refrigerant flowing out of the third port 73 of the second outdoor heat exchanger 7 is divided into two paths, one path enters the first outdoor electronic expansion valve 4, and then enters the gas-liquid separator 6 after passing through the four-way valve 2 and the second switch valve 9; the other path enters the second outdoor electronic expansion valve 10, and then enters the second outdoor electronic expansion valve 10, and then passes through the second and fourth ports 74 of the second outdoor heat exchanger 7, and then enters the gas-liquid separator 6.

[0035] Figure 3 The refrigerant flow diagram of the air conditioning unit in the cooling (defrosting) mode is shown as follows: Figure 3As shown, the S port of the four-way valve 2 is connected to the E port, the D port of the four-way valve 2 is connected to the C port, the second switch valve 9, the fourth switch valve 12 and the fifth switch valve 14 are closed, and the first switch valve 8 and the third switch valve 11 are disconnected. The refrigerant flowing out of the first outdoor electronic expansion valve 4 is divided into two paths, one path enters the second outdoor electronic expansion valve 10, then enters the second and fourth ports 74 of the second outdoor heat exchanger 7, and then enters the gas-liquid separator 6. The other path enters the third and first ports 71 of the second outdoor heat exchanger 7, then passes through the indoor electronic expansion valve 13 and the indoor heat exchanger 5, and then passes through the four-way valve 2, and enters the gas-liquid separator 6.

[0036] Figure 4 The outdoor self-circulation mode refrigerant flow diagram of the air-conditioning unit is shown as follows: Figure 4 As shown, the refrigerant no longer enters the indoor side, but circulates on the outdoor side. The S port of the four-way valve 2 is connected to the C port, the D port of the four-way valve 2 is connected to the E port, the second switch valve 9, the fourth switch valve 12 and the fifth switch valve 14 are disconnected, and the first switch valve 8 and the third switch valve 11 are closed. The refrigerant at the exhaust port of the compressor 1 passes through the first switch valve 8 and enters the second outdoor heat exchanger 7. After that, the refrigerant flowing out of the third port 73 of the second outdoor heat exchanger 7 is divided into two paths. One path enters the first outdoor electronic expansion valve 4, and then enters the second port 72 of the second outdoor heat exchanger 7 after passing through the four-way valve 2 and the third switch valve 11. The refrigerant flowing out of the fourth port 74 enters the gas-liquid separator 6; the other path enters the second outdoor electronic expansion valve 10, and then enters the second port 72 of the second outdoor heat exchanger 7. The refrigerant flowing out of the fourth port 74 enters the gas-liquid separator 6.

[0037] In this way, when the compressor 1 operates at a high frequency and the four-way valve 2 switches from cooling to heating, the high-pressure airflow generated by the operation of the high-frequency compressor 1 can be prevented from entering the indoor connecting pipeline and colliding with the liquid refrigerant in the pipeline to generate noise, while blocking the transmission of the switching noise to the indoor side.

[0038] Example 2

[0039] In a preferred embodiment 2 of the present invention, a method for controlling an air conditioning unit is provided, which is applied to the air conditioning unit in the above embodiment 1. Specifically, Figure 5 An optional flow chart of the method is shown as follows: Figure 5 As shown, the method includes the following steps S502-S504:

[0040] S502: After the air conditioner unit enters the defrost mode, detecting whether the air conditioner unit meets the defrost exit condition;

[0041] S504: If the defrost exit condition is met, the air conditioning unit is controlled to enter the outdoor self-circulation mode, so that the refrigerant of the outdoor unit exchanges heat in the refrigerant circulation pipeline composed of the first outdoor heat exchanger, the second outdoor heat exchanger and the compressor.

[0042] In the above embodiment, an air-conditioning unit that can effectively reduce noise is provided, and the unit includes a first outdoor heat exchanger and a second outdoor heat exchanger, and the second outdoor heat exchanger is respectively connected to the outdoor electronic expansion valve, the gas-liquid separator and the exhaust port of the compressor, and is used to enter the outdoor self-circulation mode after exiting defrosting, so that the refrigerant of the outdoor unit exchanges heat in the refrigerant circulation pipeline composed of the first outdoor heat exchanger, the second outdoor heat exchanger and the compressor, thereby avoiding the problem of large indoor noise caused by the reversing airflow noise when the operating mode is switched after the air-conditioning unit is defrosted, and the impact sound between the high-pressure airflow and the liquid fluid in the inner pipeline, thereby effectively reducing the noise of the indoor unit when the operating mode is switched after the air-conditioning unit is defrosted, and improving the user's comfort and experience.

[0043] Among them, controlling the air conditioning unit to enter the outdoor self-circulation mode includes: controlling the S port of the four-way valve to be connected to the C port, the D port of the four-way valve to be connected to the E port, controlling the second switch valve, the fourth switch valve and the fifth switch valve to be disconnected, and controlling the first switch valve and the third switch valve to be closed. The refrigerant flow path diagram of the outdoor self-circulation mode is shown in FIG. Figure 4 shown.

[0044] After controlling the air-conditioning unit to enter the outdoor self-circulation mode, it also includes: detecting the ratio of the exhaust pressure and the suction pressure of the compressor; when the ratio is less than a preset threshold, controlling the air-conditioning unit to enter the heating mode.

[0045] Before the air-conditioning unit runs the defrost mode, it also includes: controlling the air-conditioning unit to enter the heating mode; after the air-conditioning unit enters the heating mode, detecting whether the air-conditioning unit meets the defrost entry conditions; if the defrost entry conditions are met, controlling the air-conditioning unit to enter the defrost mode.

[0046] Among them, controlling the air conditioning unit to enter the heating mode includes: controlling the S port of the four-way valve to be connected to the C port, the D port of the four-way valve to be connected to the E port, controlling the second switch valve, the fourth switch valve and the fifth switch valve to be closed, and controlling the first switch valve and the third switch valve to be disconnected; the refrigerant flow path diagram of the heating mode is shown in FIG. Figure 2 shown.

[0047] Controlling the air conditioning unit to enter the defrost mode includes: controlling the S port of the four-way valve to connect with the E port, connecting the D port of the four-way valve to the C port, controlling the second switch valve, the fourth switch valve and the fifth switch valve to close, and controlling the first switch valve and the third switch valve to open. The refrigerant flow path diagram of the cooling mode is shown in FIG. Figure 4 shown.

[0048] Another air conditioning unit control method is provided in a preferred embodiment 2 of the present invention. Specifically, Figure 6 An optional flow chart of the method is shown as follows: Figure 6As shown, the method includes the following steps S601-S606:

[0049] S601: Heating operation; defrosting may be required during heating operation;

[0050] S602: Determine whether the defrost entry condition is met; there are many ways to determine the defrost entry condition, such as determining whether to enter the defrost state based on frosting conditions, unit operation time, or superheat parameters; if the defrost entry condition is met, enter S603, otherwise, continue heating operation;

[0051] S603: Refrigeration operation: In the refrigeration operation, the outdoor heat exchanger acts as a condenser to dissipate heat, thereby achieving a defrosting effect;

[0052] S604: Determine whether the defrost exit condition is met; if not, continue the refrigeration operation; if it is met, enter S605, and the system switches to the outdoor self-circulation mode;

[0053] S605: outdoor self-circulation; after exiting defrost, the system enters outdoor self-circulation mode, and the refrigerant circulates outdoors to avoid the problem of loud indoor noise caused by the switching of operating modes after the air conditioner unit has completed defrost;

[0054] S606: Determine whether the ratio of exhaust pressure to suction pressure reaches a threshold; if so, exit the outdoor self-circulation and enter S601 heating operation; otherwise, continue to operate in S605 outdoor self-circulation mode.

[0055] Through the above method, after exiting defrost, the outdoor self-circulation mode is entered, so that the refrigerant of the outdoor unit exchanges heat in the refrigerant circulation pipeline composed of the first outdoor heat exchanger, the second outdoor heat exchanger and the compressor, thereby avoiding the problem of large indoor noise caused by the reversing airflow noise and the impact sound between the high-pressure airflow and the liquid fluid in the inner pipeline when the operating mode is switched after the air-conditioning unit is defrosted. The noise of the indoor unit when the operating mode is switched after the air-conditioning unit is defrosted is effectively reduced, thereby improving the user's comfort and experience.

[0056] Example 3

[0057] Based on the air conditioning unit control method provided in the above-mentioned embodiment 2, a storage medium containing computer executable instructions is also provided in a preferred embodiment 3 of the present invention. When the computer executable instructions are executed by a computer processor, they are used to execute the air conditioning unit control method as described above.

[0058] In the above embodiment, an air-conditioning unit that can effectively reduce noise is provided, and the unit includes a first outdoor heat exchanger and a second outdoor heat exchanger, and the second outdoor heat exchanger is respectively connected to the outdoor electronic expansion valve, the gas-liquid separator and the exhaust port of the compressor, and is used to enter the outdoor self-circulation mode after exiting defrosting, so that the refrigerant of the outdoor unit exchanges heat in the refrigerant circulation pipeline composed of the first outdoor heat exchanger, the second outdoor heat exchanger and the compressor, thereby avoiding the problem of large indoor noise caused by the reversing airflow noise when the operating mode is switched after the air-conditioning unit is defrosted, and the impact sound between the high-pressure airflow and the liquid fluid in the inner pipeline, thereby effectively reducing the noise of the indoor unit when the operating mode is switched after the air-conditioning unit is defrosted, and improving the user's comfort and experience.

[0059] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not invented by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0060] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An air conditioning unit, comprising: A compressor (1), a four-way valve (2), a first outdoor heat exchanger (3), a first outdoor electronic expansion valve (4), an indoor heat exchanger (5) and a gas-liquid separator (6) are connected in sequence, characterized in that the air conditioning unit also includes: The second outdoor heat exchanger (7) is provided with a first port (71), a second port (72), a third port (73) and a fourth port (74); wherein the first port (71) is in communication with the third port (73), and the second port (72) is in communication with the fourth port (74); The first port (71) is connected to the indoor heat exchanger (5), the third port (73) is connected to the first outdoor electronic expansion valve (4), the second port (72) is connected to a first connection point between the third port (73) and the first outdoor electronic expansion valve (4), and the fourth port (74) is connected to an inlet of the gas-liquid separator (6); The exhaust port of the compressor (1) is also connected to a second connection point located between the first port (71) and the indoor heat exchanger (5); a first switch valve (8) located on the pipeline between the exhaust port of the compressor (1) and the second connection point; a fourth switch valve (12), located on the pipeline between the indoor heat exchanger (5) and the second connection point; An indoor electronic expansion valve (13), one end of which is connected to the indoor heat exchanger (5), and the other end of which is connected to the fourth switch valve (12); The fifth switch valve (14) is located on the pipeline between the E port of the four-way valve (2) and the indoor heat exchanger (5).

2. The air conditioning unit according to claim 1, characterized in that: The D port of the four-way valve (2) is connected to the exhaust port of the compressor (1), the C port of the four-way valve (2) is connected to the first outdoor heat exchanger (3), the S port of the four-way valve (2) is connected to a third connection point located between the fourth port (74) and the inlet of the gas-liquid separator (6), and the E port of the four-way valve (2) is connected to the indoor heat exchanger (5); the air conditioning unit further comprises: The second switch valve (9) is located on the pipeline between the S port of the four-way valve (2) and the third connection point.

3. The air conditioning unit according to claim 2, characterized in that: Also includes: a second outdoor electronic expansion valve (10) located on the pipeline between the third port (73) and the first connection point; A third switch valve (11) has one end connected to a fourth connection point located between the second switch valve (9) and the S port of the four-way valve (2), and the other end connected to a fifth connection point located between the third port (73) and the second outdoor electronic expansion valve (10).

4. A method for controlling an air conditioning unit, characterized in that: Applied to the air conditioning unit according to any one of claims 1 to 3, the method comprises: After the air conditioner unit enters the defrost mode, detecting whether the air conditioner unit meets the defrost exit condition; If the defrost exit condition is met, the air conditioning unit is controlled to enter the outdoor self-circulation mode, so that the refrigerant of the outdoor unit exchanges heat in the refrigerant circulation pipeline composed of the first outdoor heat exchanger, the second outdoor heat exchanger and the compressor.

5. The method according to claim 4, characterized in that Controlling the air conditioning unit to enter an outdoor self-circulation mode includes: The S port of the four-way valve is controlled to be connected to the C port, and the D port of the four-way valve is connected to the E port, the second switch valve, the fourth switch valve and the fifth switch valve are controlled to be disconnected, and the first switch valve and the third switch valve are controlled to be closed.

6. The method according to claim 4, characterized in that After controlling the air conditioning unit to enter the outdoor self-circulation mode, the method further includes: Detecting the ratio of the exhaust pressure and the suction pressure of the compressor; When the ratio is less than a preset threshold, the air conditioning unit is controlled to enter a heating mode.

7. The method according to claim 4, characterized in that Before the air conditioner unit runs the defrost mode, the method further includes: Controlling the air conditioning unit to enter a heating mode; After the air conditioning unit enters the heating mode, detecting whether the air conditioning unit meets a defrosting entry condition; If the defrost entry condition is met, the air conditioning unit is controlled to enter the defrost mode.

8. The method according to claim 7, characterized in that Controlling the air conditioning unit to enter a heating mode includes: Control the S port of the four-way valve to be connected to the C port, the D port of the four-way valve to be connected to the E port, control the second switch valve, the fourth switch valve and the fifth switch valve to be closed, and control the first switch valve and the third switch valve to be disconnected; Controlling the air-conditioning unit to enter the defrost mode includes: controlling the S port of the four-way valve to be connected to the E port, connecting the D port of the four-way valve to the C port, controlling the second switch valve, the fourth switch valve and the fifth switch valve to be closed, and controlling the first switch valve and the third switch valve to be disconnected.

9. A storage medium containing computer executable instructions, characterized in that: The computer executable instructions are used to execute the air conditioning unit control method according to any one of claims 4 to 8 when executed by a computer processor.

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