An air conditioning system and its control method

Abstract

This application provides an air conditioning system and its control method, relating to the field of air conditioning technology, for solving the problem of liquid return in compressors. The air conditioning system includes: an outdoor unit, comprising a compressor, a gas-liquid separator, an outdoor expansion valve, and an outdoor heat exchanger; a bypass branch; a bypass valve; a first pressure sensor; a second pressure sensor; a temperature sensor; a liquid level sensor; and a controller configured to: acquire a first cumulative number of times the bypass valve opens within a first preset time period and the operating parameters of the outdoor unit; wherein the operating parameters include the liquid level in the gas-liquid separator, the compressor's discharge temperature, discharge pressure, suction pressure, and operating status; and, when the first cumulative number of openings exceeds a first preset number, the liquid level meets a first preset condition, the discharge temperature meets a second preset condition, and the operating status meets a third preset condition, control the outdoor unit to perform compressor protection operations.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to an air conditioning system and its control method. Background Technology

[0002] Compressor liquid return refers to the refrigerant returning to the compressor's suction side in a liquid or gas-liquid two-phase state during the operation of an air conditioning system. Since liquid refrigerant is incompressible, it can cause liquid slugging in the compressor, leading to compressor wear.

[0003] Currently, to prevent liquid backflow in the compressor, air conditioning systems are usually equipped with a gas-liquid separator. After passing through the gas-liquid separator, the two-phase refrigerant returns to the suction side of the compressor, while the liquid refrigerant accumulates in the gas-liquid separator. However, some liquid refrigerant will still return to the suction side of the compressor along with the gaseous refrigerant, causing liquid slugging in the compressor. Summary of the Invention

[0004] This application provides an air conditioning system and its control method to solve the problem of liquid return from the compressor.

[0005] To achieve the above objectives, this application adopts the following technical solution.

[0006] In a first aspect, embodiments of this application provide an air conditioning system, comprising: an outdoor unit including a compressor, a gas-liquid separator, an outdoor expansion valve, and an outdoor heat exchanger; a bypass branch, one end connected to the inlet of the gas-liquid separator and the other end connected to the outlet of the compressor; a bypass valve disposed on the bypass branch for controlling the opening and closing of the bypass branch; a first pressure sensor disposed at the inlet of the compressor for detecting the suction pressure of the compressor; a second pressure sensor disposed at the outlet of the compressor for detecting the discharge pressure of the compressor; a temperature sensor for detecting the discharge temperature of the compressor; a liquid level sensor disposed on the gas-liquid separator for detecting the liquid level height of the gas-liquid separator; and a controller configured to: acquire a first cumulative number of times the bypass valve is opened within a first preset time period and the operating parameters of the outdoor unit; wherein the operating parameters include the liquid level height of the gas-liquid separator, the discharge temperature of the compressor, the discharge pressure, the suction pressure, and the operating status; and control the outdoor unit to perform compressor protection operation when the first cumulative number of openings is greater than the first preset number, the liquid level height meets the first preset condition, the discharge temperature meets the second preset condition, and the operating status meets the third preset condition.

[0007] The technical solution provided in this application provides at least the following beneficial effects: This application provides an air conditioning system that, when the first cumulative number of openings exceeds a first preset number, the liquid level meets a first preset condition, the exhaust temperature meets a second preset condition, and the operating state meets a third preset condition, controls the outdoor unit to perform compressor protection operations. It is understood that if the first cumulative number of openings exceeds the first preset number, it indicates that the bypass valve is opening frequently. Frequent opening of the bypass valve will cause the liquid level in the gas-liquid separator to rise. Consequently, when the operating parameters (liquid level, exhaust temperature, and operating state) meet the preset conditions, liquid refrigerant in the gas-liquid separator will enter the compressor, thereby damaging the compressor. Therefore, in this situation, controlling the outdoor unit to perform compressor protection operations protects the compressor, enabling stable compressor operation, reducing the compressor's failure rate, and extending its service life.

[0008] In some embodiments, the controller is further configured to: if the first cumulative number of openings is less than or equal to the first preset number of openings, acquire the second cumulative number of openings of the bypass valve within a second preset time period; and if the second cumulative number of openings is greater than the second preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, control the outdoor unit to perform compressor protection operation.

[0009] In some embodiments, the controller is configured to control the outdoor unit to perform compressor protection operations, specifically configured to: control the outdoor unit to stop and adjust the opening of the outdoor expansion valve to the initial opening; after the outdoor unit has been stopped for a third preset duration, adjust the opening of the outdoor expansion valve so that the compressor's exhaust temperature is within a preset stable range.

[0010] In some embodiments, the first preset condition includes: the liquid level is greater than a preset height; the second preset condition includes any one of the following: within a third preset time period, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to a preset threshold; or, within a fourth preset time period, the cumulative time during which the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to the preset threshold reaches the third preset time period; the third preset condition includes: the operating state is the power-on state.

[0011] In some embodiments, the first cumulative number of openings is the cumulative number of times the bypass valve opens during the starting and pre-stop phases within a first preset time period, provided that the operating parameters meet the first opening condition. The operating parameters further include: the compressor's continuous shutdown duration, the air conditioning system's operating mode, and the operating phase. The operating phase includes a starting phase, a normal operating phase, and a pre-stop phase; the operating mode includes a heating mode and a cooling mode. The first opening condition includes: the operating phase is the starting phase, and the suction pressure is less than or equal to a first preset threshold; or, the operating phase is the pre-stop phase, and the suction pressure is less than or equal to a second preset threshold; or, the operating phase is the pre-stop phase, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than a third preset threshold, the operating mode is the heating mode, and the continuous shutdown duration is greater than or equal to a preset shutdown duration.

[0012] In some embodiments, the second cumulative opening count is the cumulative number of times the bypass valve opens during the starting and pre-stopping phases within a second preset time period when the operating parameters meet the second opening condition; the second opening condition includes: the operating phase is the starting phase, and the suction pressure is less than or equal to a fourth preset threshold; wherein the fourth preset threshold is greater than a first preset threshold; or, the operating phase is the pre-stopping phase, and the suction pressure is less than or equal to a second preset threshold; or, the operating phase is the pre-stopping phase, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than a third preset threshold, the operating mode is the heating mode, and the continuous shutdown time is greater than or equal to a preset shutdown time.

[0013] Secondly, embodiments of this application provide a control method for an air conditioning system. The method is applied to an air conditioning system and includes: acquiring a first cumulative number of times a bypass valve is opened within a first preset time period and the operating parameters of the outdoor unit; wherein the operating parameters include the liquid level of the gas-liquid separator, the discharge temperature of the compressor, the discharge pressure, the suction pressure, and the operating status; and controlling the outdoor unit to perform compressor protection operation when the first cumulative number of openings is greater than a first preset number, the liquid level meets a first preset condition, the discharge temperature meets a second preset condition, and the operating status meets a third preset condition.

[0014] Thirdly, embodiments of this application provide a controller, including: one or more processors; one or more memories; wherein the one or more memories are used to store computer program code, the computer program code including computer instructions, and when the one or more processors execute the computer instructions, the controller executes any of the air conditioning system control methods provided in the second aspect.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium including computer instructions that, when executed on a computer, cause the computer to perform any of the air conditioning system control methods provided in the second aspect.

[0016] Fifthly, embodiments of the present invention provide a computer program product that can be directly loaded into a memory and contains software code. After being loaded and executed by a computer, the computer program product can realize any of the air conditioning system control methods provided in the second aspect.

[0017] It should be noted that the aforementioned computer instructions may be stored, in whole or in part, on a computer-readable storage medium. This computer-readable storage medium may be packaged together with the controller's processor or may be packaged separately from the controller's processor; this application does not impose any limitations on this.

[0018] The beneficial effects described in aspects two through five of this application can be referred to the analysis of the beneficial effects of aspect one, and will not be repeated here. Attached Figure Description

[0019] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0020] Figure 1 This is a schematic diagram of the composition of an air conditioning system provided in an embodiment of this application;

[0021] Figure 2 This is a schematic diagram showing the installation position of an electronic expansion valve according to an embodiment of this application;

[0022] Figure 3 A schematic diagram of another electronic expansion valve mounting position provided in an embodiment of this application.

[0023] Figure 4 This is a schematic diagram of the structure of an air conditioning system provided in an embodiment of this application;

[0024] Figure 5 This is a connection diagram of a four-way valve provided in an embodiment of this application;

[0025] Figure 6 This is a connection diagram of another four-way valve provided in an embodiment of this application;

[0026] Figure 7 This application provides a schematic diagram of the circulation principle of an air conditioning system.

[0027] Figure 8This is a schematic diagram of the circulation principle of another air conditioning system provided in an embodiment of this application;

[0028] Figure 9 A hardware configuration block diagram of an air conditioning system provided in an embodiment of this application;

[0029] Figure 10 This is a schematic diagram of the structure of a controller provided in an embodiment of this application;

[0030] Figure 11 A flowchart of a control method for an air conditioning system provided in an embodiment of this application;

[0031] Figure 12 A flowchart of a control method for an air conditioning system provided in an embodiment of this application;

[0032] Figure 13 A flowchart of a control method for an air conditioning system provided in an embodiment of this application;

[0033] Figure 14 A flowchart illustrating a control method for an air conditioning system provided in this application embodiment. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0037] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, when describing pipelines, the terms "connected" and "linked" as used in this application have the meaning of establishing electrical connection. The specific meaning needs to be understood in conjunction with the context.

[0038] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0039] During compressor operation, situations frequently arise where the discharge pressure is too high or the suction pressure is too low. To reduce the discharge pressure or increase the suction pressure, the bypass solenoid valve is opened. However, the suction pressure is relatively low during the start-up and pre-shutdown phases, so the bypass solenoid valve needs to be opened frequently to increase the suction pressure. However, frequent opening and closing of the bypass solenoid valve causes the liquid level in the gas-liquid separator to rise, which can lead to damage to the compressor's liquid return system.

[0040] Based on this, this application provides a control method for an air conditioning system. When the cumulative number of times the system is activated exceeds a first preset number of times, the liquid level meets a first preset condition, the exhaust temperature meets a second preset condition, and the operating state meets a third preset condition, the outdoor unit is controlled to perform a compressor protection operation. In this situation, controlling the outdoor unit to perform a compressor protection operation protects the compressor, enabling stable compressor operation, reducing the compressor's failure rate, and extending its service life.

[0041] Figure 1 This is a schematic diagram illustrating the composition of an air conditioning system provided in accordance with an exemplary embodiment of this application. Figure 1 As shown, the air conditioning system 10 includes an outdoor unit 11, multiple indoor units 12 connected in parallel, and a controller 13. Figure 1 (not shown in the image) and throttling device 14 ( Figure 1 (Not shown in the image).

[0042] In some embodiments, the outdoor unit 11 is typically installed outdoors to assist in heat exchange in the indoor environment.

[0043] In some embodiments, the indoor unit 12 is typically installed indoors and can be an indoor wall-mounted unit or an indoor cabinet unit; this application embodiment does not limit this.

[0044] The outdoor unit 11 and the indoor unit 12 are connected by a pipe, and a throttling device 14 is installed on the pipe between the indoor unit 12 and the outdoor unit 11. The pipe, also known as a gas-liquid pipe, includes a gas pipe for transporting gaseous refrigerant and a liquid pipe for transporting two-phase refrigerant.

[0045] The throttling device 14 is used to regulate the fluid flow rate in the air conditioning gas-liquid pipe and to regulate the refrigerant flow rate. The throttling device includes an outdoor expansion valve 106 and an indoor expansion valve 111. For example... Figure 2 As shown, the outdoor expansion valve 106 can be independent of the outdoor unit 11, and the indoor expansion valve 111 can be independent of the indoor unit 12, as follows. Figure 3 As shown, the outdoor expansion valve 106 can also be part of the outdoor unit 11, and the indoor expansion valve 111 can also be part of the indoor unit 12.

[0046] In addition, both the outdoor unit 11 and the indoor unit 12 are connected to the controller 13 and perform related operations according to the controller's instructions.

[0047] Figure 4 This is a schematic diagram of the structure of an air conditioning system provided in accordance with an exemplary embodiment of this application. Figure 4 As shown, the air conditioning system includes an outdoor unit 11, an indoor unit 12, and a controller 13. Figure 4 (Not shown in the image).

[0048] The outdoor unit 11 includes a gas-side shut-off valve 101, a four-way valve 102, a bypass valve 103, a compressor 104, an outdoor heat exchanger 105, an outdoor expansion valve 106, a liquid level sensor 107, a gas-liquid separator 108, and a liquid-side shut-off valve 109. The indoor unit 12 includes an indoor heat exchanger 110 and an indoor expansion valve 111.

[0049] In some embodiments, one end of the gas-side shut-off valve 101 is connected to the indoor heat exchanger 110, and the other end is connected to the four-way valve 102.

[0050] In some embodiments, the four ports of the four-way valve 102 are respectively connected to the compressor 104, the outdoor heat exchanger 105, the gas-liquid separator 108, and the gas-side shut-off valve 101. The four-way valve 102 is used to achieve mutual conversion between cooling and heating by changing the flow direction of refrigerant in the system pipeline.

[0051] For example, the four ports of the four-way valve 102 are port D, port E, port S, and port C. Port D of the four-way valve 102 is connected to the compressor 104, port E of the four-way valve 102 is connected to the indoor heat exchanger 110, port S of the four-way valve 102 is connected to the gas-liquid separator 108, and port C of the four-way valve 102 is connected to the outdoor heat exchanger 105. In cooling mode, as... Figure 5As shown, the four-way valve's D port is connected to the C port, and its E port is connected to the S port. In heating mode, as... Figure 6 As shown, the D port of the four-way valve is connected to the E port, and the C port is connected to the S port.

[0052] In some embodiments, a bypass valve 103 is disposed on a bypass branch for controlling the opening and closing of the bypass branch. One end of the bypass branch is connected to the inlet of the gas-liquid separator 108, and the other end is connected to the outlet of the compressor 104.

[0053] In some embodiments, compressor 104 is configured between four-way valve 102 and gas-liquid separator 108 for compressing refrigerant supplied by gas-liquid separator 108 and supplying the compressed refrigerant via four-way valve 102 to gas-side shut-off valve 101. Compressor 104 may be a variable-capacity inverter compressor that performs inverter-based speed control.

[0054] In some embodiments, multiple compressors 104 may be provided, and the multiple compressors are connected in parallel. The present application embodiment does not limit the number of compressors 104.

[0055] In some embodiments, the outdoor heat exchanger 105 has a first inlet / outlet for allowing refrigerant to flow through a gas-liquid separator 108 between itself and the suction port of the compressor 104, and a second inlet / outlet for allowing refrigerant to flow between the outdoor heat exchanger 105 and the outdoor expansion valve 106. The outdoor heat exchanger 105 facilitates heat exchange between a hot air compressor flowing in a heat transfer tube connected between the first and second inlets / outlets and outdoor air. During cooling, the outdoor heat exchanger 105 operates as a condenser; during heating, it operates as an evaporator.

[0056] In some embodiments, the outdoor expansion valve 106 has the function of expanding and depressurizing the refrigerant flowing through it, and can be used to regulate the refrigerant supply in the pipeline. If the outdoor expansion valve 106 decreases its opening, the flow resistance of the refrigerant through it increases. If the outdoor expansion valve 106 increases its opening, the flow resistance decreases. Thus, even if the states of other components in the circuit remain unchanged, the refrigerant flow rate to the indoor unit 12 will change when the opening of the outdoor expansion valve 106 changes.

[0057] In some embodiments, a liquid level sensor 107 is disposed on a gas-liquid separator 108 for detecting the liquid level height of the liquid refrigerant in the gas-liquid separator 108.

[0058] In some embodiments, one end of the gas-liquid separator 108 is connected to the compressor 104, and the other end is connected to the outdoor heat exchanger 105 via a four-way valve 102. In the gas-liquid separator 108, the refrigerant flowing from the outdoor heat exchanger 105 to the compressor 104 via the four-way valve 102 is separated into gaseous refrigerant and liquid refrigerant. Furthermore, gaseous refrigerant is primarily supplied from the gas-liquid separator 108 to the suction port of the compressor 104.

[0059] In some embodiments, one end of the liquid-side shut-off valve 109 is connected to the outdoor heat exchanger 105 via the outdoor expansion valve 106, and the other end is connected to the indoor heat exchanger 110 via the indoor expansion valve 111.

[0060] In some embodiments, the indoor heat exchanger 110 has a third inlet for allowing liquid refrigerant to flow between it and the indoor expansion valve 111, and a fourth inlet for allowing gaseous refrigerant to flow between it and the outlet of the compressor 104. The indoor heat exchanger 110 facilitates heat exchange between the refrigerant flowing in the heat transfer tube connected between the third and fourth inlets and the indoor air. During cooling, the indoor heat exchanger 110 operates as an evaporator; during heating, it operates as a condenser.

[0061] In some embodiments, the indoor expansion valve 111 has the function of expanding and depressurizing the refrigerant flowing through it, and can be used to regulate the supply of refrigerant in the pipeline. Furthermore, a description of the indoor expansion valve 111 can be found in the detailed description of the outdoor expansion valve 106 described above, and will not be repeated here.

[0062] In the embodiments shown in this application, controller 13 refers to a device that can generate operation control signals according to instruction opcodes and timing signals, instructing the air conditioning system 10 to execute control commands. Exemplarily, the controller can be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The controller can also be other devices with processing functions, such as circuits, devices, or software modules; this application does not impose any limitations on this.

[0063] In addition, the controller 13 can be used to control the operation of various components inside the air conditioning system 10 so that the various components of the air conditioning system 10 can operate to achieve the predetermined functions of the air conditioning system.

[0064] Figure 7This application provides a schematic diagram of the hardware structure of a controller, as shown in the embodiment. Figure 7 As shown, the controller 13 includes an acquisition module 301 and a control module 302.

[0065] In some embodiments, the acquisition module 301 is used to acquire the first cumulative number of times the bypass valve is opened within a first preset time period and the operating parameters of the outdoor unit; wherein, the operating parameters include the liquid level of the gas-liquid separator, the exhaust temperature of the compressor, the exhaust pressure, the suction pressure, and the operating status.

[0066] In some embodiments, the control module 302 is used to control the outdoor unit to perform compressor protection operation when the first cumulative number of openings is greater than the first preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition.

[0067] Figure 8 This is a schematic diagram illustrating the circulation principle of an air conditioning system according to an exemplary embodiment of this application. Figure 8 As shown, during cooling, the air conditioning system 10 uses compressor 104 to compress low-temperature, low-pressure gaseous refrigerant into high-temperature, high-pressure gaseous refrigerant, which is then discharged to outdoor heat exchanger 105. The high-temperature, high-pressure gaseous refrigerant exchanges heat with outdoor air in outdoor heat exchanger 105, releasing heat. This released heat is carried into the outdoor ambient air, causing the refrigerant to undergo a phase change and condense into a liquid or gas-liquid two-phase refrigerant. The refrigerant flows out of outdoor heat exchanger 105 and enters outdoor expansion valve 106 to cool and depressurize, becoming a low-temperature, low-pressure refrigerant. This low-temperature, low-pressure refrigerant enters indoor heat exchanger 110 to exchange heat with indoor air, absorbing heat from the indoor air and lowering the indoor temperature, thus achieving a cooling effect. Alternatively, the refrigerant undergoes a phase change and evaporates into a low-temperature, low-pressure gaseous refrigerant, which then passes through gas-side shut-off valve 101 and four-way valve 102 into gas-liquid separator 108. From gas-liquid separator 108, gaseous refrigerant is mainly supplied to the suction port of compressor 104, achieving refrigerant recycling.

[0068] Figure 9 This is a schematic diagram illustrating the circulation principle of an air conditioning system according to an exemplary embodiment of this application. Figure 9As shown, when the air conditioning system 10 is in heating mode, the compressor 104 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant, which is then discharged to the indoor heat exchanger 110. The high-temperature, high-pressure gaseous refrigerant exchanges heat with the indoor air in the indoor heat exchanger 110, releasing heat. This released heat is carried into the indoor air, raising the indoor temperature and achieving the heating effect. The refrigerant undergoes a phase change and condenses into a liquid or gas-liquid two-phase refrigerant. The refrigerant flows out of the indoor heat exchanger 110 and enters the indoor expansion valve 111 to cool and depressurize, becoming a low-temperature, low-pressure refrigerant. The low-temperature, low-pressure refrigerant enters the outdoor heat exchanger 105 to exchange heat with the outdoor air, where it undergoes a phase change and evaporates into a low-temperature, low-pressure gaseous refrigerant, which flows back into the compressor 104, achieving refrigerant recycling.

[0069] Figure 10 This is a hardware configuration block diagram of an air conditioning system provided in an embodiment of this application. For example... Figure 10 As shown, the air conditioning system 10 may also include one or more of the following: a first pressure sensor 201, a second pressure sensor 202, a temperature sensor 203, a communicator 204, and a memory 205.

[0070] In some embodiments, a first pressure sensor 201 is disposed at the inlet of the compressor 104 for detecting the compressor's suction pressure.

[0071] In some embodiments, a second pressure sensor 202 is disposed at the outlet of the compressor 104 for detecting the compressor's discharge pressure.

[0072] In some embodiments, a temperature sensor 203 is disposed at the outlet of the compressor 104 to detect the discharge temperature of the compressor.

[0073] In some embodiments, the communicator 204 is used to establish communication connections with other network entities, such as establishing communication connections with terminal devices. The communicator 204 may include a radio frequency (RF) module, a cellular module, a wireless fidelity (WIFI) module, and a GPS module, etc. Taking an RF module as an example, the RF module can be used for signal reception and transmission; specifically, it sends received information to the controller 13 for processing; additionally, it transmits signals generated by the controller 13. Typically, the RF circuit may include, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low-noise amplifier (LNA), a duplexer, etc.

[0074] The memory 205 can be used to store software programs and data. The controller 13 executes various functions of the air conditioning system 10 and performs data processing by running the software programs or data stored in the memory 205. The memory 205 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. The memory 205 stores the operating system that enables the air conditioning system 10 to run. In this application, the memory 205 may store the operating system and various application programs, and may also store code that executes the control method of the air conditioning system provided in the embodiments of this application.

[0075] Those skilled in the art will understand that Figure 10 The hardware structure shown does not constitute a limitation on the air conditioning system. The air conditioning system may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0076] The embodiments provided in this application will now be described in detail with reference to the accompanying drawings.

[0077] like Figure 11 As shown in the figure, this application provides a control method for an air conditioning system, which includes the following steps:

[0078] S101, The controller acquires the first cumulative number of times the bypass valve is opened within the first preset time period and the operating parameters of the outdoor unit.

[0079] The operating parameters include the liquid level height of the gas-liquid separator detected by the liquid level sensor, the exhaust temperature of the compressor detected by the temperature sensor, the exhaust pressure detected by the first pressure sensor, the suction pressure detected by the second pressure sensor, the operating status, the duration of continuous shutdown, and the operating mode and stage of the air conditioning system.

[0080] The operation phases include the start-up phase, the normal operation phase, and the pre-stop phase, and the operation modes include the heating mode and the cooling mode.

[0081] It should be noted that the piping connections within an air conditioning system are complex and varied. The process of ensuring stable operation of all components and rapid refrigerant circulation within the piping during system startup is called the start-up phase. To prevent compressor damage caused by excessive liquid refrigerant being drawn from the low-pressure side during the next startup, the controller transfers the refrigerant from the low-pressure side to the high-pressure side before the system completely stops operating. In other words, during heating, the refrigerant is transferred from the outdoor heat exchanger to the indoor heat exchanger; this process is called the pre-shutdown phase.

[0082] In some embodiments, the air conditioning system is frequently turned on or off, causing the system to frequently enter the start-up phase and the pre-stop phase.

[0083] In one example, when a user needs to use the air conditioning system for cooling or heating, the user can send a power-on command to the air conditioning system via a terminal device or the air conditioning system's remote control. In response to the power-on command, the controller controls the various components of the air conditioning system to start operating. Similarly, when the user does not need to use the air conditioning system for cooling or heating, the user can also send a power-off command to the air conditioning system via a terminal device or the air conditioning system's remote control. In response to the power-off command, the controller controls the various components of the air conditioning system to shut down and stop operating.

[0084] In another example, the controller can control the air conditioning system to turn on or off based on the user-set temperature, indoor ambient temperature, and outdoor ambient temperature.

[0085] Understandably, frequent starting and stopping of the air conditioning system will cause it to frequently enter the startup and pre-stop phases. During these phases, the compressor's suction pressure is generally low. To maintain a stable suction pressure, the controller will open the bypass valve to increase the suction pressure. Therefore, if the air conditioning system frequently enters these phases, the bypass valve will open and close frequently. This frequent opening and closing of the bypass valve will cause the liquid refrigerant level in the gas-liquid separator to rise, leading to liquid refrigerant entering the compressor and damaging it.

[0086] In some embodiments, the first cumulative number of openings is the cumulative number of times the bypass valve is opened during the starting phase and the pre-stop phase within a first preset time period when the operating parameters meet the first opening condition.

[0087] The first start-up conditions include: the operation phase is the start-up phase, and the intake pressure is less than or equal to the first preset threshold; or, the operation phase is the pre-stop phase, and the intake pressure is less than or equal to the second preset threshold; or, the operation phase is the pre-stop phase, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than the third preset threshold, the operation mode is the heating mode, and the continuous shutdown time is greater than or equal to the preset shutdown time.

[0088] Optionally, the first preset threshold is greater than the lower limit of the compressor's stable suction pressure range.

[0089] In some embodiments, corresponding to the first opening condition, the controller controls the bypass valve to close when the operating parameters meet the first closing condition.

[0090] The first shutdown condition includes: the operation phase is the start-up phase, and the continuous opening time of the bypass valve reaches the preset opening time; or, the operation phase is the pre-stop phase, and the suction pressure is greater than the second preset threshold; or, the operation phase is the pre-stop phase, and the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is greater than or equal to the third preset threshold, and / or the operation mode is the cooling mode, and / or the continuous shutdown time is less than the preset shutdown time.

[0091] S102. When the cumulative number of openings exceeds the first preset number, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, the controller controls the outdoor unit to perform compressor protection operation.

[0092] The first preset condition includes: the liquid level is greater than a preset height.

[0093] The second preset condition includes any one of the following: within the third preset time period, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to a preset threshold; or, within the fourth preset time period, the cumulative time during which the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to the preset threshold reaches the third preset time period.

[0094] The third preset condition includes: the running status is powered on.

[0095] Optionally, the exhaust temperature mentioned above is the minimum exhaust temperature detected by the exhaust temperature sensor.

[0096] In some embodiments, when the first cumulative number of openings is greater than the first preset number, the controller determines whether the liquid level meets the first preset condition, whether the exhaust temperature meets the second preset condition, and whether the operating status meets the third preset condition.

[0097] It should be understood that if the first cumulative number of openings exceeds the first preset number, it indicates that the bypass valve is opening more frequently, which in turn indicates that the liquid level in the gas-liquid separator is high. This makes it easier for liquid refrigerant in the gas-liquid separator to enter the compressor, potentially causing damage. Therefore, when the first cumulative number of openings exceeds the first preset number, a further judgment is made to determine whether liquid refrigerant in the gas-liquid separator will enter the compressor.

[0098] In some embodiments, when the first cumulative number of openings is greater than the first preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, the controller controls the outdoor unit to perform compressor protection operation.

[0099] The compressor protection operations include:

[0100] S1. The controller controls the outdoor unit to stop and adjusts the opening degree of the outdoor expansion valve to the initial opening degree.

[0101] In some embodiments, the initial opening degree is the opening degree determined by the controller based on the user - set temperature and the ambient temperature when the air - conditioning system is just started.

[0102] In some embodiments, the controller obtains the first opening degree of the outdoor expansion valve before adjustment.

[0103] S2. After the shutdown duration of the outdoor unit reaches the third preset duration, the controller adjusts the opening degree of the outdoor expansion valve so that the exhaust temperature of the compressor is within the preset stable range.

[0104] In some embodiments, after the shutdown duration of the outdoor unit reaches the third preset duration, the controller controls the outdoor unit to start, and when the outdoor unit starts, reduces the opening degree of the outdoor expansion valve to n times of the above - mentioned first opening degree. Here, n ∈ R and 0 < n < 1. For example, n is 0.75.

[0105] It can be understood that when the opening degree of the outdoor expansion valve is the first opening degree, it indicates that the exhaust superheat degree of the compressor is relatively low, and when the exhaust superheat degree is relatively low, it is easy for the liquid refrigerant in the gas - liquid separator to enter the compressor. Therefore, when controlling the outdoor unit to perform the compressor protection operation, it is necessary to increase the exhaust superheat degree, and reducing the opening degree of the outdoor expansion valve can increase the exhaust superheat degree.

[0106] In some embodiments, after reducing the opening degree of the outdoor expansion valve to n times of the above - mentioned first opening degree, the controller determines whether the liquid level height of the gas - liquid separator is less than or equal to the preset height.

[0107] In some embodiments, when the liquid level height of the gas - liquid separator is greater than the preset height, the controller reduces the opening degree of the outdoor expansion valve so that the liquid level height of the gas - liquid separator is less than or equal to the preset height.

[0108] In some embodiments, when the liquid level height of the gas - liquid separator is less than or equal to the preset height, the controller maintains the current opening degree of the outdoor expansion valve so that the exhaust temperature of the compressor is within the preset stable range.

[0109] The following combines with Figure 12 As shown in the following logic block diagram, an exemplary introduction is made to the complete process of the controller controlling the outdoor unit to perform the compressor protection operation.

[0110] As Figure 12 shown, the process starts.

[0111] S11. The controller controls the outdoor unit to stop and adjusts the opening degree of the outdoor expansion valve to the initial opening degree.

[0112] S12. After the outdoor unit has been off for a third preset period of time, the controller will turn on the outdoor unit.

[0113] S13. The controller reduces the opening of the outdoor expansion valve to n times the first opening.

[0114] Determine whether the liquid level is less than or equal to the preset height.

[0115] If so, proceed to step S15.

[0116] If not, proceed to step S14.

[0117] S14. The controller reduces the opening of the outdoor expansion valve.

[0118] Determine whether the liquid level is less than or equal to the preset height.

[0119] If so, proceed to step S15.

[0120] If not, continue to reduce the opening of the outdoor expansion valve until the liquid level is greater than the preset height.

[0121] S15. The controller maintains the current opening of the outdoor expansion valve to keep the compressor's discharge temperature within a preset stable range.

[0122] based on Figure 11 The embodiment shown in this application provides a control method for an air conditioning system. When the first cumulative number of openings exceeds a first preset number, the liquid level meets a first preset condition, the exhaust temperature meets a second preset condition, and the operating state meets a third preset condition, the outdoor unit is controlled to perform a compressor protection operation. It is understood that if the first cumulative number of openings exceeds the first preset number, it indicates that the bypass valve is opening frequently. Frequent opening of the bypass valve will cause the liquid level in the gas-liquid separator to rise. Consequently, when the operating parameters (liquid level, exhaust temperature, and operating state) meet the preset conditions, liquid refrigerant in the gas-liquid separator will enter the compressor, thereby damaging the compressor. Therefore, in this situation, the outdoor unit is controlled to perform a compressor protection operation to protect the compressor, enabling stable compressor operation, reducing the compressor's failure rate, and extending its service life.

[0123] In some embodiments, such as Figure 13 As shown, the method also includes the following steps:

[0124] S201. If the first cumulative number of openings is less than or equal to the first preset number of openings, obtain the second cumulative number of openings of the bypass valve within a second preset time period.

[0125] In some embodiments, the second cumulative opening count is the cumulative number of times the bypass valve is opened during the starting phase and the pre-stop phase within a second preset time period when the operating parameters meet the second opening condition.

[0126] The second start-up conditions include: the operation phase is the start-up phase, and the intake pressure is less than or equal to the fourth preset threshold; wherein the fourth preset threshold is greater than the first preset threshold; or, the operation phase is the pre-stop phase, and the intake pressure is less than or equal to the second preset threshold; or, the operation phase is the pre-stop phase, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than the third preset threshold, the operation mode is the heating mode, and the continuous shutdown duration is greater than or equal to the preset shutdown duration.

[0127] Optionally, the second preset duration can be equal to, greater than, or less than the first preset duration.

[0128] It should be understood that, because the first preset threshold is greater than the lower limit of the compressor's stable suction pressure range, under the first opening condition, the bypass valve opens relatively infrequently, and the liquid level in the gas-liquid separator is less likely to rise. Therefore, the number of times the bypass valve opens is less likely to exceed the first preset number, and the liquid level is less likely to exceed the preset height. This results in fewer opportunities for the controller to trigger compressor protection operations on the outdoor unit, affecting compressor reliability. However, under the second opening condition, because the fourth preset threshold is greater than the first preset threshold, the number of times the bypass valve opens relatively increases, and the liquid level in the gas-liquid separator is more likely to rise. Therefore, the number of times the bypass valve opens is more likely to exceed the second preset number, and the liquid level is more likely to exceed the preset height. This results in more opportunities for the controller to trigger compressor protection operations on the outdoor unit, thereby improving compressor reliability.

[0129] In some embodiments, corresponding to the second opening condition, the controller controls the bypass valve to close when the operating parameters meet the second closing condition.

[0130] The second shut-off conditions include: the operation phase is the start-up phase, and the continuous opening duration of the bypass valve reaches the preset opening duration; or, the operation phase is the pre-stop phase, and the suction pressure is greater than the second preset threshold; or, the operation phase is the pre-stop phase, and the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is greater than or equal to the third preset threshold, and / or the operation mode is the cooling mode, and / or the continuous shutdown duration is less than the preset shutdown duration.

[0131] S202, when the second cumulative number of openings is greater than the second preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, the outdoor unit is controlled to perform compressor protection operation.

[0132] Optionally, the second preset number of times is greater than the first preset number of times.

[0133] Furthermore, for the details of step S201, please refer to the specific description of step S102 above, which will not be repeated here.

[0134] The following is combined with, for example Figure 14 The logic block diagram shown exemplifies the complete flow of the control method for an air conditioning system.

[0135] like Figure 14 As shown, the process begins.

[0136] S21. The controller acquires the first cumulative number of times the bypass valve is opened within the first preset time period and the operating parameters of the outdoor unit.

[0137] Determine whether the first cumulative number of times the device has been activated is less than or equal to the first preset number of times.

[0138] If so, then proceed with steps S26 and S22 in sequence.

[0139] If not, proceed to step S22.

[0140] S22. Determine whether the liquid level height meets the first preset condition.

[0141] If so, proceed to step S23.

[0142] If not, the process ends.

[0143] S23. Determine whether the exhaust temperature meets the second preset condition.

[0144] If so, proceed to step S24.

[0145] If not, the process ends.

[0146] S24. Determine whether the running status meets the third preset condition.

[0147] If so, proceed to step S25.

[0148] If not, the process ends.

[0149] S25, Control the outdoor unit to perform compressor protection operation.

[0150] S26. Obtain the second cumulative number of times the bypass valve is opened within the second preset time period.

[0151] As can be seen, the above mainly describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, the embodiments of this application provide corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the modules and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0152] This application embodiment can divide the controller into functional modules according to the above method example. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. Optionally, the module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0153] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An air conditioning system, characterized in that, include: The outdoor unit includes a compressor, a gas-liquid separator, an outdoor expansion valve, and an outdoor heat exchanger; A bypass branch is connected at one end to the inlet of the gas-liquid separator and at the other end to the outlet of the compressor. A bypass valve is provided on the bypass branch and is used to control the opening and closing of the bypass branch; A first pressure sensor is installed at the inlet of the compressor to detect the suction pressure of the compressor. The second pressure sensor is located at the outlet of the compressor and is used to detect the discharge pressure of the compressor. A temperature sensor is used to detect the exhaust temperature of the compressor; A liquid level sensor is installed on the gas-liquid separator to detect the liquid level height in the gas-liquid separator; The controller is configured as follows: The system acquires the first cumulative number of times the bypass valve opens within a first preset time period and the operating parameters of the outdoor unit; wherein the operating parameters include the liquid level of the gas-liquid separator, the discharge temperature of the compressor, the discharge pressure, the suction pressure, and the operating status; If the first cumulative number of openings is greater than the first preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, the outdoor unit is controlled to perform compressor protection operation. The first preset condition includes: the liquid level is greater than a preset height; The second preset condition includes any one of the following: within a third preset time period, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to a preset threshold; or, within a fourth preset time period, the cumulative time during which the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to the preset threshold reaches the third preset time period. The third preset condition includes: the operating state is the power-on state.

2. The air conditioning system according to claim 1, characterized in that, The controller is also configured to: If the first cumulative number of openings is less than or equal to the first preset number of openings, the second cumulative number of openings of the bypass valve within a second preset time period is obtained. If the second cumulative number of openings is greater than the second preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, the outdoor unit is controlled to perform a compressor protection operation.

3. The air conditioning system according to claim 1 or 2, characterized in that, The controller is configured to control the outdoor unit to perform compressor protection operations, specifically configured as follows: Control the outdoor unit to stop and adjust the opening of the outdoor expansion valve to the initial opening; After the outdoor unit has been off for a third preset period of time, the opening of the outdoor expansion valve is adjusted so that the exhaust temperature of the compressor is within a preset stable range.

4. The air conditioning system according to claim 2, characterized in that, The first cumulative opening count is the cumulative number of times the bypass valve is opened during the starting and pre-stopping phases within the first preset time period when the operating parameters meet the first opening condition; wherein, the operating parameters further include: the continuous shutdown time of the compressor, the operating mode and operating phase of the air conditioning system; wherein, the operating phase includes the starting phase, the normal operation phase and the pre-stopping phase, and the operating mode includes the heating mode and the cooling mode. The first activation condition includes: The operation phase is the starting phase, and the intake pressure is less than or equal to a first preset threshold; or, the operation phase is the pre-stop phase, and the intake pressure is less than or equal to a second preset threshold; or, the operation phase is the pre-stop phase, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than a third preset threshold, the operation mode is the heating mode, and the continuous shutdown duration is greater than or equal to a preset shutdown duration.

5. The air conditioning system according to claim 4, characterized in that, The second cumulative opening count is the cumulative number of times the bypass valve is opened during the starting and pre-stopping phases within the second preset time period, provided that the operating parameters meet the second opening condition. The second activation condition includes: the operation phase is the starting phase, and the intake pressure is less than or equal to a fourth preset threshold; wherein the fourth preset threshold is greater than the first preset threshold; or, the operation phase is the pre-stop phase, and the intake pressure is less than or equal to the second preset threshold; or, the operation phase is the pre-stop phase, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than the third preset threshold, the operation mode is the heating mode, and the continuous shutdown duration is greater than or equal to the preset shutdown duration.

6. A control method for an air conditioning system, characterized in that, Applied to an air conditioning system, the method includes: The system acquires the first cumulative number of times the bypass valve opens within a first preset time period and the operating parameters of the outdoor unit; wherein, the operating parameters include the liquid level in the gas-liquid separator, the compressor's discharge temperature, discharge pressure, suction pressure, and operating status; If the first cumulative number of openings is greater than the first preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, the outdoor unit is controlled to perform compressor protection operation. The first preset condition includes: the liquid level is greater than a preset height; The second preset condition includes any one of the following: within a third preset time period, the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to a preset threshold; or, within a fourth preset time period, the cumulative time during which the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure is less than or equal to the preset threshold reaches the third preset time period. The third preset condition includes: the operating state is the power-on state.

7. The method according to claim 6, characterized in that, The method further includes: If the first cumulative number of openings is less than or equal to the first preset number of openings, the second cumulative number of openings of the bypass valve within a second preset time period is obtained. If the second cumulative number of openings is greater than the second preset number of openings, the liquid level meets the first preset condition, the exhaust temperature meets the second preset condition, and the operating status meets the third preset condition, the outdoor unit is controlled to perform a compressor protection operation.

8. The method according to claim 6 or 7, characterized in that, The control of the outdoor unit to perform compressor protection operations includes: Control the outdoor unit to stop and adjust the opening of the outdoor expansion valve to the initial opening; After the outdoor unit has been off for a third preset period of time, the opening of the outdoor expansion valve is adjusted so that the exhaust temperature of the compressor is within a preset stable range.

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