Air conditioning system and control method thereof

Abstract

The application provides an air conditioning system and a control method thereof, and relates to the technical field of air conditioning, and is used for reducing the probability of compressor damage when heating starts. A controller is configured to: in response to a heating start instruction of the air conditioning system, acquire an outdoor environment temperature and a working state of a four-way valve; in the case that the outdoor environment temperature is lower than a preset temperature and the four-way valve is in a first working state, control an outdoor expansion valve to open to a preset initial opening degree, control the compressor to operate at a target frequency, and control a bypass valve to close; when a reversing condition of the four-way valve is met, control the four-way valve to switch from the first working state to a second working state, and control the expansion valve to close at the same time; and after the four-way valve switches to the second working state, control the opening degree of the expansion valve based on the exhaust gas superheat degree of the compressor, and control the opening and closing of the bypass valve based on the suction pressure of the compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning, in particular to an air conditioning system and a control method thereof. BACKGROUND

[0002] With the improvement of living standards, air conditioners have entered thousands of households and become an indispensable household appliance in people's lives. Based on the demand for thermal comfort of the public, consumers hope that air conditioners can operate normally within a relatively wide temperature range, and some export countries have also explicitly required air conditioners to be able to start heating normally at minus 25 degrees.

[0003] At present, in the heating start process of the air conditioning system, the outdoor electronic expansion valve is fully opened, and the refrigerant can flow back to the gas-liquid separator in a large amount, which can not only reduce the circulation time of the refrigerant, but also speed up the air outlet time of the air conditioner. However, when the volume of the gas-liquid separator is not large enough, liquid refrigerant in the air conditioning system may enter the compressor during the heating start process, and the compressor may be damaged due to liquid compression. SUMMARY

[0004] The present application provides an air conditioning system and a control method thereof, which are used to reduce the probability of compressor damage during heating start.

[0005] In a first aspect, an air conditioning system is provided, which comprises: a refrigerant circulation loop, which circulates refrigerant in a loop composed of a compressor, a condenser, an expansion valve, an evaporator, a four-way valve, and a gas-liquid separator;

[0006] a compressor, configured to compress low-temperature and low-pressure refrigerant gas into high-temperature and high-pressure refrigerant gas and discharge it to the condenser;

[0007] an outdoor heat exchanger and an indoor heat exchanger, wherein one functions as a condenser and the other functions as an evaporator;

[0008] a four-way valve, configured to control the flow direction of the refrigerant in the refrigerant circulation loop; when the four-way valve is in a first working state, the outdoor heat exchanger functions as a condenser; when the four-way valve is in a second working state, the outdoor heat exchanger functions as an evaporator;

[0009] a bypass branch, arranged between the inlet of the gas-liquid separator and the exhaust port of the compressor, configured to divert part of the refrigerant flowing from the compressor to the condenser and combine it with the refrigerant flowing to the inlet of the gas-liquid separator;

[0010] a bypass valve, arranged on the bypass branch, configured to control the opening and closing of the bypass branch;

[0011] and a controller, configured to:

[0012] In response to a heating start instruction of the air conditioning system, an outdoor environment temperature and a working state of the four-way valve are acquired;

[0013] In a case where the outdoor environment temperature is lower than a preset temperature and the four-way valve is in the first working state, the outdoor expansion valve is controlled to open to a preset initial opening degree, the compressor is controlled to operate at a target frequency, and the bypass valve is controlled to close;

[0014] When the reversing condition of the four-way valve is met, the four-way valve is controlled to switch from the first working state to the second working state, and the expansion valve is controlled to close;

[0015] After the four-way valve switches to the second working state, the opening degree of the expansion valve is controlled based on the discharge superheat of the compressor, and the opening and closing of the bypass valve is controlled based on the suction pressure of the compressor.

[0016] The technical scheme provided by the embodiments of the present application at least brings the following beneficial effects: the air conditioning system provided by the embodiments of the present application controls the expansion valve to close when the four-way valve switches from the first working state to the second working state, thereby preventing the liquid refrigerant in the outdoor heat exchanger from entering the compressor through the expansion valve and causing damage to the compressor. The opening and closing of the bypass valve is controlled based on the suction pressure of the compressor, so that the bypass branch is connected, and at this time, a part of the high-temperature and high-pressure gaseous refrigerant in the compressor can be diverted to enter the gas-liquid separator through the bypass branch, so that the liquid refrigerant in the gas-liquid separator evaporates into gaseous refrigerant and then enters the compressor, and the refrigerant between the compressor and the gas-liquid separator forms an internal circulation, thereby reducing the liquid refrigerant in the gas-liquid separator. When it is detected that the discharge superheat of the compressor reaches a first preset threshold, the outdoor fan is controlled to operate at a target speed, the heat exchange rate of the outdoor heat exchanger is improved, the liquid refrigerant in the outdoor heat exchanger is quickly evaporated into gaseous refrigerant, and the content of the liquid refrigerant in the outdoor heat exchanger is reduced. When it is detected that the compressor reaches a second superheat threshold, the compressor has established a certain superheat, and only a small amount of liquid refrigerant exists in the outdoor heat exchanger, at this time, the expansion valve is opened, the liquid refrigerant enters the gas-liquid separator, and the gaseous refrigerant enters the compressor, thereby reducing the content of the liquid refrigerant in the air conditioning system. When the gas-liquid separator is not large enough, the excessive liquid refrigerant in the heating start process can be prevented from entering the compressor, and the probability of damage to the compressor during the heating start of the air conditioning system is reduced.

[0017] In some embodiments, the air conditioning system further includes an outdoor fan for dissipating heat from the outdoor heat exchanger; and the controller is further configured to: in a case where the outdoor environment temperature is lower than a preset temperature and the four-way valve is in the first working state, control the outdoor fan to stop operating; after the four-way valve switches to the second working state, control the outdoor fan to stop operating when the discharge superheat of the compressor is lower than a first preset superheat; and control the outdoor fan to operate at a target speed when the discharge superheat of the compressor rises to reach a first superheat threshold.

[0018] In some embodiments, the controller is configured to control the opening degree of the expansion valve based on the exhaust gas superheat degree of the compressor after the four-way valve switches to the second working state, including: after the four-way valve switches to the second working state, when the exhaust gas superheat degree of the compressor is lower than a second superheat degree threshold, the second superheat degree threshold being higher than the first superheat degree threshold, the controller controls the expansion valve to keep in the closed state; when the exhaust gas superheat degree of the compressor rises to the second superheat degree threshold, the controller controls the expansion valve to open to a preset initial opening degree.

[0019] In some embodiments, the controller is further configured to adjust the opening degree of the expansion valve to make the exhaust gas superheat degree of the compressor reach a target exhaust gas superheat degree, or the suction gas superheat degree of the compressor reach a target suction gas superheat degree after the start-up control end condition is met.

[0020] In some embodiments, the controller is configured to control the opening and closing of the bypass valve based on the suction pressure of the compressor after the four-way valve switches to the second working state, including: after the four-way valve switches to the second working state, when the suction pressure of the compressor is lower than a preset pressure threshold, the controller controls the bypass valve to open; after the suction pressure of the compressor reaches the preset pressure threshold, the controller controls the bypass valve to close.

[0021] In some embodiments, the controller is further configured to control the bypass valve to close after the start-up control end condition is met.

[0022] In some embodiments, the start-up control end condition includes any one of: the opening time length of the bypass valve reaches a preset time length; or, the exhaust gas superheat degree of the compressor reaches a third superheat degree threshold, the third superheat degree threshold being greater than the second superheat degree threshold.

[0023] In some embodiments, the controller is further configured to, in a case where the outdoor ambient temperature is lower than a preset temperature and the four-way valve is in the second working state, control the expansion valve to close and control the compressor to operate at a target frequency; control the opening degree of the expansion valve based on the exhaust gas superheat degree of the compressor, and control the opening and closing of the bypass valve based on the suction pressure of the compressor.

[0024] In some embodiments, the air conditioning system further includes: an outdoor fan for dissipating heat from the outdoor heat exchanger; the controller is further configured to, in a case where the outdoor ambient temperature is lower than a preset temperature and the four-way valve is in the second working state, control the outdoor fan to stop operating; when the exhaust gas superheat degree of the compressor rises to the first superheat degree threshold, control the outdoor fan to operate at a target rotating speed.

[0025] In a second aspect, a control method of an air conditioning system is provided. The method comprises: in response to a heating start instruction of the air conditioning system, acquiring an outdoor environment temperature and a working state of a four-way valve; in a case where the outdoor environment temperature is lower than a preset temperature and the four-way valve is in a first working state, controlling an outdoor expansion valve to open to a preset initial opening degree, controlling a compressor to operate at a target frequency, and controlling a bypass valve to close; when a reversing condition of the four-way valve is met, controlling the four-way valve to switch from the first working state to a second working state, and controlling the expansion valve to close; after the four-way valve switches to the second working state, controlling an opening degree of the expansion valve based on a discharge superheat of the compressor, and controlling the bypass valve based on a suction pressure of the compressor.

[0026] In a third aspect, an embodiment of the present application provides a controller, comprising: one or more processors; and one or more memories; wherein the one or more memories are configured to store computer program codes, the computer program codes comprising computer instructions, and when the one or more processors execute the computer instructions, the controller performs the control method of the air conditioning system provided in the second aspect.

[0027] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, which comprises computer instructions, and when the computer instructions are executed on a computer, the computer performs the control method of the air conditioning system provided in the second aspect.

[0028] In a fifth aspect, an embodiment of the present application provides a computer program product, which can be directly loaded into a memory and contains software codes, and when the computer program product is loaded and executed by a computer, the control method of the air conditioning system provided in the second aspect can be implemented.

[0029] It should be noted that the computer instructions described above can be stored in the computer readable storage medium in whole or in part. The computer readable storage medium can be packaged together with the processor of the controller or packaged separately from the processor of the controller, and the present application does not limit the computer readable storage medium.

[0030] The beneficial effects of the second aspect to the fifth aspect described in the present application can be analyzed with reference to the beneficial effects of the first aspect, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the technical solutions of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0032] Figure 1 A schematic diagram of the composition of the air conditioning system provided in the embodiments of the present application is shown in the following figure:

[0033] Figure 2 A structure schematic diagram of a refrigerant circulation loop of an air conditioning system provided for an embodiment of the present application;

[0034] Figure 3 A structure schematic diagram of an outdoor unit provided for an embodiment of the present application;

[0035] Figure 4 A hardware configuration block diagram of an air conditioning system provided for an embodiment of the present application;

[0036] Figure 5 A flow schematic diagram of a control method of an air conditioning system provided for an embodiment of the present application;

[0037] Figure 6 A flow schematic diagram of another control method of an air conditioning system provided for an embodiment of the present application;

[0038] Figure 7 A flow schematic diagram of another control method of an air conditioning system provided for an embodiment of the present application;

[0039] Figure 8 A flow schematic diagram of another control method of an air conditioning system provided for an embodiment of the present application;

[0040] Figure 9 A flow schematic diagram of another control method of an air conditioning system provided for an embodiment of the present application;

[0041] Figure 10 A flow schematic diagram of another control method of an air conditioning system provided for an embodiment of the present application;

[0042] Figure 11 A flow schematic diagram of another control method of an air conditioning system provided for an embodiment of the present application;

[0043] Figure 12 A flow schematic diagram of another control method of an air conditioning system provided for an embodiment of the present application;

[0044] Figure 13 A hardware structure schematic diagram of a controller provided for an embodiment of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without any creative work, fall within the protection scope of the present application.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] As described in the background section above, if the volume of the gas-liquid separator is not large enough, liquid refrigerant in the air conditioning system may enter the compressor during the heating start-up process, causing the compressor to become liquid compressed and thus damaging the compressor.

[0051] Based on this, this application provides an air conditioning system and its control method. When the outdoor temperature is lower than a preset temperature and the four-way valve is in its first operating state, the flow rate of the refrigerant is controlled by controlling the opening of the outdoor expansion valve. This causes the pressure at both ends of the four-way valve to differ due to the different flow rates. When the pressure difference at both ends of the four-way valve reaches the reversing condition, the four-way valve switches to its second operating state, and the expansion valve is closed, preventing the refrigerant from flowing rapidly through the air conditioning system. When the compressor's suction pressure is detected to be lower than a pressure threshold, the bypass valve is opened to connect the bypass branch. At this time, a portion of the high-temperature, high-pressure gaseous refrigerant in the compressor can be diverted through the bypass branch into the gas-liquid separator, causing the refrigerant in the gas-liquid separator to be converted into gaseous refrigerant before re-entering the compressor, forming an internal circulation between the compressor and the gas-liquid separator. When the compressor's exhaust superheat is detected to reach a first preset threshold, the outdoor fan is turned on to improve the heat exchange efficiency of the outdoor heat exchanger, rapidly converting the liquid refrigerant in the outdoor heat exchanger into gaseous refrigerant and reducing the liquid refrigerant content in the outdoor heat exchanger. When the compressor reaches the second superheat threshold, there is only a small amount of liquid refrigerant in the outdoor heat exchanger. At this time, the expansion valve is opened, and even if the volume of the gas-liquid separator is not large enough, no liquid refrigerant will enter the compressor, reducing the occurrence of liquid return in the system and preventing the compressor from being damaged due to liquid compression.

[0052] To further describe the solution in this application, as follows: Figure 1 The diagram shown is a schematic representation of an air conditioning system according to an embodiment of this application. Figure 1 As shown, the air conditioning system 10 includes an outdoor unit 11, multiple indoor units 12, and a controller 13. Figure 1 (Not shown in the image).

[0053] Outdoor unit 11 is typically installed outdoors for heat exchange with the outdoor environment. Outdoor unit 11 is located on the opposite side of the outdoor unit 12, separated by a wall.

[0054] Multiple indoor units 12, taking one indoor unit 12 as an example, the indoor unit 12 is usually installed indoors to exchange heat with the indoor environment to achieve the effect of heating or cooling.

[0055] There is a pipe connection between the outdoor unit 11 and the indoor unit 12. 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.

[0056] In some embodiments, the controller 13 refers to a device that can generate operation control signals according to instruction operation codes and timing signals, and instruct the air conditioning system to execute control instructions. Exemplarily, the controller can be a central processing unit (CPU), a general-purpose processor network processor (NP), a digital signal processing (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 a circuit, a device, or a software module, and the embodiments of the present application do not make any limitation in this regard.

[0057] 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 operate to achieve the predetermined functions of the air conditioning system.

[0058] In some embodiments, the air conditioning system can further include a remote controller, which can exist independently from the air conditioning system, and a plurality of buttons are arranged on the remote controller, and different buttons can adjust the state of the air conditioning system.

[0059] Figure 2 A structure diagram of a refrigerant circulation loop of an air conditioning system according to an embodiment of the present application is provided. As shown in the figure, the circulation loop of the air conditioning system 10 includes a compressor 111, a four-way valve 112, a gas-liquid separator 113, an outdoor heat exchanger 114, an expansion valve 115, and an indoor heat exchanger 116. Figure 2

[0060] In some embodiments, the compressor 111 is connected to the controller 13. The compressor 111 is arranged between the four-way valve 112 and the gas-liquid separator 113, and is used to compress the refrigerant delivered by the gas-liquid separator 113, and deliver the compressed refrigerant to the air conditioning system through the four-way valve 112. The compressor 111 can be an inverter compressor with variable capacity based on inverter speed control.

[0061] In some embodiments, the four-way valve 112 is connected to the controller 13. The four-way valve 112 is a control valve with four oil ports, and the four oil ports are connected to the compressor 111, the gas-liquid separator 113, the outdoor heat exchanger 114, and the indoor heat exchanger 116, respectively. The four-way valve 112 is used to realize the mutual conversion between refrigeration and heating by changing the flow direction of the refrigerant in the system pipeline.

[0062] ​In some embodiments, the solenoid coil on the four-way valve is energized, in an open state. The pilot spool moves right under the magnetic force generated by the solenoid coil against the tension of the compression spring, and the high-pressure gas enters the left end piston cavity after entering the capillary tube, and on the other side, the gas in the right end piston cavity is discharged. Due to the pressure difference between the two ends of the piston, the piston and the main spool move right, so that the exhaust pipe is connected with the indoor unit connection pipe, and the other two connection pipes are connected, forming a heating cycle.

[0063] In some embodiments, one end of the gas-liquid separator 113 is connected to the compressor 111, and the other end is connected to the four-way valve 112. In the gas-liquid separator 113, the refrigerant flowing from the outdoor heat exchanger 114 to the compressor 111 through the four-way valve 112 is separated into gaseous refrigerant and liquid refrigerant. And the suction port of the compressor 111 is mainly supplied with gaseous refrigerant from the gas-liquid separator 113.

[0064] In some embodiments, the outdoor heat exchanger 114 is connected to the controller 13. One end of the outdoor heat exchanger 114 is connected to the four-way valve 112, and the other end is connected to the expansion valve 115. The outdoor heat exchanger 114 is usually arranged outdoors and is used for heat exchange with the outdoor environment. In the cooling mode, the gaseous refrigerant in the outdoor heat exchanger 114 is converted into liquid refrigerant by heat release, and works as a condenser; in the heating mode, the liquid refrigerant in the outdoor heat exchanger 114 is converted into gaseous refrigerant by heat absorption, and works as an evaporator.

[0065] In some embodiments, the expansion valve 115 is connected to the controller 13. The expansion valve 115 is arranged between the outdoor heat exchanger 114 and the indoor heat exchanger 116. The expansion valve 115 is composed of a valve body and a coil, and has the function of expanding and reducing the pressure of the refrigerant flowing through the expansion valve 115, and can be used to adjust the supply amount of the refrigerant in the pipeline. If the opening degree of the expansion valve 115 is reduced, the flow resistance of the refrigerant passing through the expansion valve 115 increases. If the opening degree of the expansion valve 115 is increased, the flow resistance of the refrigerant passing through the expansion valve 115 decreases. In this way, even if the state of other devices in the circuit does not change, when the opening degree of the electronic expansion valve 115 changes, the refrigerant flow in the air conditioning system will also change.

[0066] In some embodiments, the indoor heat exchanger 116 is connected to the controller. One end of the indoor heat exchanger 116 is connected to the expansion valve, and the other end is connected to the four-way valve. The indoor heat exchanger 116 is usually arranged indoors and is used for heat exchange with the indoor environment. In the cooling mode, the liquid refrigerant in the indoor heat exchanger 116 is converted into gaseous refrigerant by heat absorption, and works as an evaporator; in the heating mode, the gaseous refrigerant in the indoor heat exchanger 116 is converted into liquid refrigerant by heat release, and works as a condenser.

[0067] Figure 3 An outdoor unit 11 structure schematic diagram provided by the embodiments of the present application. As shown in FIG. 1, the outdoor unit 11 includes a compressor 111, a four-way valve 112, a gas-liquid separator 113, an outdoor heat exchanger 114, an expansion valve 115, an indoor heat exchanger 116, and a controller 13. Figure 3As shown, the outdoor unit 11 includes a compressor 111, a four-way valve 112, a gas-liquid separator 113, an outdoor heat exchanger 114, an expansion valve 115, a bypass valve 117, an outdoor fan 118, a gas shutoff valve 119, a liquid shutoff valve 120, a first pressure sensor 121, a second pressure sensor 122, and a temperature sensor 123 (not shown in the figure).

[0068] For the descriptions of the compressor 111, the four-way valve 112, the gas-liquid separator 113, the outdoor heat exchanger 114, and the expansion valve 115, please refer to the descriptions in the above Figure 2 , which will not be repeated here.

[0069] In some embodiments, as shown in Figure 3 , a bypass branch is arranged between the inlet of the gas-liquid separator 113 and the exhaust port of the compressor, for diverting part of the refrigerant flowing from the compressor 111 to the condenser (i.e., the outdoor heat exchanger 114) and merging with the refrigerant flowing to the inlet of the gas-liquid separator.

[0070] In some embodiments, the bypass valve 117 is arranged on the bypass branch, for controlling the opening and closing of the bypass branch. When the bypass valve is in the open state, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor can enter the gas-liquid separator through the bypass branch, and heat the refrigerant in the gas-liquid separator into gaseous refrigerant, at which time the gaseous refrigerant in the gas-liquid separator flows back to the compressor through the suction port of the compressor, forming an internal circulation.

[0071] In some embodiments, as shown in Figure 3 , one end of the bypass valve 117 is connected with a bypass capillary tube.

[0072] In some embodiments, the outdoor fan 118 generates an air flow of outdoor air through the outdoor heat exchanger 114, to promote the heat exchange between the refrigerant in the outdoor heat exchanger and the outdoor environment.

[0073] In some embodiments, the gas shutoff valve 119 is connected with the controller 13, and is arranged on the gas pipe of the outdoor unit 11, for controlling the communication and shutoff of the gas pipe.

[0074] In some embodiments, the liquid shutoff valve 120 is connected with the controller 13, and is arranged on the liquid pipe of the outdoor unit 11, for controlling the communication and shutoff of the liquid pipe.

[0075] In some embodiments, the first pressure sensor 121 is connected with the controller 13, and is arranged at the exhaust port of the compressor 111, for detecting the exhaust pressure value at the exhaust port of the compressor, and sending the detected exhaust pressure value to the controller 13.

[0076] In some embodiments, the second pressure sensor 122 is connected with the controller 13, and is arranged at a suction port of the compressor 111, for detecting a suction pressure value of the suction port of the compressor, and sending the detected suction pressure value to the controller 13.

[0077] In some embodiments, the temperature sensor 123 is connected with the controller 13, and can be arranged on the outdoor unit 11, for detecting a temperature value of an environment where the outdoor unit 11 is located, and sending the detected temperature value of the environment where the outdoor unit 11 is located to the controller 13.

[0078] Figure 4 Fig. 1 shows a hardware configuration block diagram of an air conditioning system provided by an embodiment of the present application. As shown in the figure, the air conditioning system 10 can further include one of the following: a communicator 130 and a memory 140. Figure 4

[0079] In some embodiments, the communicator 130 is configured to establish a communication connection with other network entities, for example, a terminal device. The communicator 130 can include a radio frequency (RF) module, a cellular module, a wireless fidelity (WIFI) module, and a GPS module, etc. Taking the RF module as an example, the RF module can be configured to receive and send signals, in particular, send the received information to the controller 13 for processing, and send the signals generated by the controller 13. Generally, the RF circuit can include, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier (LNA), a duplexer, etc.

[0080] The memory 140 can be configured to store software programs and data. The controller 13 can execute various functions and data processing of the air conditioning system 10 by running the software programs or data stored in the memory 140. The memory 140 can include a high-speed random access memory, and can further include a non-volatile memory, for example, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device. The memory 140 stores an operating system that enables the air conditioning system 10 to run. In the present application, the memory 140 can store an operating system and various application programs, and can further store codes for executing the control method of the air conditioning system provided by the embodiments of the present application.

[0081] Those skilled in the art can understand that the hardware structure shown in the figure does not constitute a limitation on the air conditioning system, and the air conditioning system can include more or fewer components than those shown in the figure, or combine certain components, or different component arrangements. Figure 4

[0082] The embodiments provided by the present application will be specifically described below with reference to the accompanying drawings.​​

[0083] The embodiment of the present application provides a control method of an air conditioning system, which is applied to a controller. The controller can be the controller 13 shown in the above Figure 4 Figure 5 The method comprises the following steps:

[0084] S101, in response to a heating start instruction of the air conditioning system, acquiring an outdoor environment temperature and a working state of a four-way valve.

[0085] In some embodiments, when a user needs to use the air conditioning system for heating, the user can issue a heating start instruction to the air conditioning system through a terminal device or a remote controller of the air conditioning system. After receiving the heating start instruction, the controller controls the air conditioning system to enter a heating start state in response to the heating start instruction of the air conditioning system.

[0086] In some embodiments, when the air conditioning system enters the heating start state, the controller acquires the outdoor environment temperature through a temperature sensor and acquires the working state of the four-way valve. The working state of the four-way valve comprises a first working state and a second working state. The first working state can be a closed state, and the second working state can be an open state.

[0087] S102, in the case that the outdoor environment temperature is lower than a preset temperature and the four-way valve is in the first working state, controlling an outdoor expansion valve to open to a preset initial opening degree, controlling a compressor to operate at a target frequency, and controlling a bypass valve to close.

[0088] The preset temperature is a temperature preset when the air conditioning system is manufactured, for example, the preset temperature is minus 5 degrees Celsius.

[0089] It can be understood that in the case that the outdoor environment temperature is lower than the preset temperature and the four-way valve is in the first working state, it represents that the outdoor environment is a low-temperature environment, and the four-way valve is in the closed state. The air conditioning system needs to start heating in the low-temperature environment. Therefore, the controller controls the outdoor expansion valve to open to the preset initial opening degree, controls the compressor to operate at the target frequency, and controls the bypass valve to close.

[0090] It can be understood that the controller controls the outdoor expansion valve to open to the preset initial opening degree, so that the refrigerant flow path resistance of the outdoor expansion valve is increased, the refrigerant circulation amount is reduced, and after the four-way valve is switched to the second working state, the four-way valve can be closed in time, and the liquid refrigerant entering the compressor is reduced.

[0091] For example, the preset initial opening degree of the expansion valve is preset when the expansion valve is manufactured, for example, the preset initial opening degree of the expansion valve is 10% of the maximum opening degree.

[0092] ​In some embodiments, the controller controls the compressor to operate at a target frequency, and the refrigerant entering the compressor through the outdoor expansion valve is compressed, and the high-temperature and high-pressure gaseous refrigerant obtained by compression is discharged. After the high-temperature and high-pressure gaseous refrigerant is discharged from the compressor, the exhaust pressure on the discharge side of the compressor increases, the suction pressure on the suction side of the compressor remains unchanged, and therefore the pressure difference between the discharge side and the suction side of the compressor increases with the working time of the compressor. The discharge side of the compressor is connected to one oil port of the four-way valve, and the suction side of the compressor is connected to another oil port of the four-way valve. The pressure difference between the discharge side and the suction side of the compressor, i.e., the pressure difference between the two oil ports of the four-way valve.

[0093] In some embodiments, the bypass valve is controlled to be closed, and the bypass branch is disconnected, so that the high-temperature and high-pressure gaseous refrigerant discharged from the compressor is not divided, which is beneficial to the capacity of the unit.

[0094] S103, when the reversing condition of the four-way valve is met, the four-way valve is controlled to switch from the first working state to the second working state, and the expansion valve is controlled to be closed.

[0095] The reversing condition of the four-way valve can be pre-set when the air conditioning system is shipped, for example, the four-way valve reverses when the pressure difference is 1 MPa.

[0096] In some embodiments, when the controller detects that the pressure difference between the two sides of the four-way valve reaches the reversing pressure difference, the controller controls the four-way valve to reverse, and the four-way valve switches from the first working state to the second working state. The second working state is an open state, i.e., the four-way valve switches from a closed state to an open state. After the four-way valve switches to the open state, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor enters the indoor heat exchanger through the four-way valve, and the high-temperature and high-pressure gaseous refrigerant is condensed and releases heat in the indoor heat exchanger. At this time, the air conditioning system switches from a cooling mode to a heating mode.

[0097] In some embodiments, when the controller controls the four-way valve to switch to the second working state, the expansion valve is controlled to be closed. After the expansion valve is closed, the liquid refrigerant in the indoor heat exchanger cannot flow into the outdoor heat exchanger through the expansion valve, reducing the liquid refrigerant in the outdoor heat exchanger, and thereby reducing the liquid refrigerant entering the gas-liquid separator from the outdoor heat exchanger.

[0098] S104, after the four-way valve switches to the second working state, the opening degree of the expansion valve is controlled based on the exhaust superheat degree of the compressor, and the opening and closing of the bypass valve is controlled based on the suction pressure of the compressor.

[0099] In some embodiments, after the four-way valve switches to the second working state, i.e., the four-way valve is in an open state, the opening degree of the expansion valve is controlled according to the exhaust superheat degree of the compressor, to prevent the liquid refrigerant in the indoor heat exchanger from entering the compressor and causing damage to the compressor.

[0100] In some embodiments, the opening and closing of the bypass valve is controlled based on the suction pressure of the compressor. When the bypass valve is closed, the bypass branch is disconnected; when the bypass valve is opened, the bypass branch is connected.

[0101] Optionally, as shown in FIG. 10, the step S104 can be implemented as the following steps: Figure 6

[0102] S1041, after the four-way valve switches to the second working state, when the suction pressure of the compressor is lower than a preset pressure threshold, the bypass valve is controlled to be opened.

[0103] In some embodiments, when the controller detects that the suction pressure of the compressor is lower than the preset pressure threshold, if the bypass valve is not opened, the bypass valve is controlled to be opened. If the bypass valve is opened, the bypass valve is controlled to continue to be opened. After the bypass valve is opened, the bypass branch is connected, and part of the high-temperature and high-pressure gaseous refrigerant discharged from the compressor can be mixed with the refrigerant flowing to the gas-liquid separator. After the mixing, the high-temperature and high-pressure gaseous refrigerant enters the gas-liquid separator, evaporates the liquid refrigerant in the gas-liquid separator into gaseous refrigerant, and then flows into the compressor again, forming an internal circulation of the refrigerant between the compressor and the gas-liquid separator, so that a small amount of liquid refrigerant exists in the gas-liquid separator.

[0104] S1042, after the suction pressure of the compressor reaches the preset pressure threshold, the bypass valve is controlled to be closed.

[0105] In some embodiments, after the controller detects that the suction pressure of the compressor reaches the preset pressure threshold through the second pressure sensor, the bypass valve is controlled to be closed.

[0106] The preset pressure threshold can be preset when the air conditioning system is manufactured. For example, the preset pressure threshold is 0.2 MPa.

[0107] S1043, when the outdoor ambient temperature is lower than a preset temperature and the four-way valve is in the second working state, the outdoor fan is controlled to stop running.

[0108] In some embodiments, when the controller detects that the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the second working state, if the outdoor fan is in a running state, the outdoor fan is controlled to stop running; if the outdoor fan is in a stopped running state, the outdoor fan is controlled to continue to be in the stopped running state.

[0109] S1044, when the discharge superheat of the compressor increases to a first superheat threshold, the outdoor fan is controlled to run at a target rotating speed.

[0110] The first superheat threshold can be preset when the air conditioning system is manufactured. For example, the first superheat threshold is 5°C. ​

[0111] In some embodiments, the compressor is controlled to operate in the frequency-boosting mode, and the exhaust gas superheat degree is gradually increased. When the exhaust gas superheat degree of the compressor reaches a first superheat threshold, the outdoor fan is controlled to operate at a target rotating speed. The outdoor fan operating at the target rotating speed can increase the heat exchange rate between the outdoor heat exchanger and the outdoor environment, thereby increasing the rate of the liquid refrigerant in the outdoor heat exchanger evaporating into gaseous refrigerant, and reducing the content of the liquid refrigerant in the outdoor heat exchanger.

[0112] For example, the target rotating speed is determined by the outdoor environment temperature, and the lower the outdoor environment temperature, the faster the rotating speed of the outdoor fan; and the higher the outdoor environment temperature, the slower the rotating speed of the outdoor fan.

[0113] S1045, after the four-way valve is switched to the second working state, when the exhaust gas superheat degree of the compressor is lower than a second superheat threshold, the expansion valve is controlled to remain in the closed state.

[0114] For example, the second superheat threshold is higher than the first superheat threshold. For example, the second superheat threshold is 10°C.

[0115] In some embodiments, when the controller detects that the exhaust gas superheat degree is lower than the second superheat threshold, the expansion valve is controlled to remain in the closed state, preventing the liquid refrigerant in the outdoor heat exchanger from flowing through the expansion valve and eventually entering the compressor, thereby preventing damage to the compressor.

[0116] S1046, when the exhaust gas superheat degree of the compressor increases to the second superheat threshold, the expansion valve is controlled to open to a preset initial opening degree.

[0117] For example, the initial preset opening degree is 8% of the maximum opening degree.

[0118] In some embodiments, when the controller detects that the exhaust gas superheat degree of the compressor reaches the second superheat threshold, the process consumes a long time, and the liquid refrigerant in the outdoor heat exchanger has evaporated into gaseous refrigerant, and the liquid refrigerant in the gas-liquid separator has also evaporated into gaseous refrigerant. At this time, the expansion valve is opened to the preset initial opening degree, and only a small amount of liquid refrigerant present in the indoor heat exchanger will enter the gas-liquid separator, and will not enter the compressor.

[0119] In some embodiments, as shown in FIG. 1, after step S104, the method further includes the following steps: Figure 7

[0120] S105, when the start-up control end condition is reached, the heating start-up of the air conditioning system is completed, and the start-up control ends.

[0121] ​Optionally, the start control end condition can be that the opening duration of the bypass valve reaches a preset duration, at which time the compressor is started, and there is a large amount of gaseous refrigerant in the air conditioning system, and a small amount of liquid refrigerant flows from the outdoor unit to the gas-liquid separator, and the liquid refrigerant does not flow to the compressor.

[0122] The preset duration is preset when the air conditioning system is shipped, for example, the preset duration is 10 minutes.

[0123] Optionally, the start control end condition can be that the exhaust superheat degree of the compressor reaches a third superheat degree threshold, at which time the compressor is started, and the air conditioning system establishes a certain superheat degree, and the refrigerant entering the compressor is not liquid refrigerant.

[0124] In some embodiments, after the start control end condition is met, the air conditioning system establishes a certain superheat degree, the bypass valve is controlled to be closed, and the bypass branch is disconnected. The high-temperature and high-pressure gaseous refrigerant in the compressor does not need to enter the gas-liquid separator through the bypass branch, and the refrigerant entering the compressor is also not liquid refrigerant. Opening the bypass valve will also cause noise, and closing the bypass valve after the start end condition is met can also reduce noise and improve user experience.

[0125] In some embodiments, after the start control end condition is met, the refrigerant flow can also be adjusted by adjusting the opening degree of the expansion valve, so as to adjust the exhaust superheat degree. The larger the opening degree of the expansion valve, the smaller the refrigerant flow resistance, the larger the refrigerant flow of the air conditioning system, and the smaller the exhaust superheat degree. At this time, the opening degree of the expansion valve is reduced, so that the exhaust superheat degree is increased. The smaller the opening degree of the expansion valve, the larger the refrigerant flow resistance, the smaller the refrigerant flow of the air conditioning system, and the larger the exhaust superheat degree. At this time, the opening degree of the expansion valve is increased, so that the exhaust superheat degree is reduced.

[0126] Based on Figure 5The embodiments shown at least bring the following beneficial effects: the embodiments provide an air conditioning system and a control method thereof. When the controller detects that the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the closed state, the compressor is controlled to operate at a target frequency. The discharge pressure of the compressor is high and one oil port of the four-way valve is connected, and the suction pressure of the compressor is low and the other oil port of the four-way valve is connected, so that there is a pressure difference between the two oil ports of the four-way valve. When it is detected that the pressure difference between the two oil ports of the four-way valve reaches the reversing condition, the four-way valve is controlled to switch to the open state. At the same time, the expansion valve is controlled to be closed to prevent the liquid refrigerant in the outdoor heat exchanger from entering the compressor, causing damage to the compressor. When the controller obtains the suction pressure of the compressor being lower than the pressure threshold value through the second pressure sensor, the bypass valve is controlled to be opened to connect the bypass branch. At this time, a part of the high-temperature and high-pressure gaseous refrigerant in the compressor can be diverted through the bypass branch into the gas-liquid separator, so that the liquid refrigerant in the gas-liquid separator evaporates into gaseous refrigerant and then enters the compressor, and the refrigerant between the compressor and the gas-liquid separator forms an internal circulation. When it is detected that the discharge superheat of the compressor reaches the first preset threshold value, the outdoor fan is controlled to operate at a target speed to improve the heat exchange efficiency of the outdoor heat exchanger, rapidly evaporate the liquid refrigerant in the outdoor heat exchanger into gaseous refrigerant, and reduce the content of the liquid refrigerant in the outdoor heat exchanger. When the compressor reaches the second superheat threshold value, the compressor has established a certain superheat, and there is a small amount of liquid refrigerant in the outdoor heat exchanger. At this time, the expansion valve is opened, the liquid refrigerant enters the gas-liquid separation, and the gaseous refrigerant enters the compressor, reducing the content of the liquid refrigerant in the air conditioning system. When the gas-liquid separator is not large enough, it can prevent too much liquid refrigerant from entering the compressor during the heating start process, reducing the probability of damage to the compressor during the heating start of the air conditioning system.

[0127] The above embodiments focus on the description of the outdoor ambient temperature being lower than the preset temperature and the four-way valve being in the closed state in the air conditioning system and the control method thereof provided by the embodiments. In some embodiments, the embodiments provide a description of the outdoor ambient temperature being lower than the preset temperature and the four-way valve being in the open state, as shown in Figure 8 The method further includes the following steps:

[0128] S201, in response to a heating start instruction of the air conditioning system, obtaining an outdoor ambient temperature and a working state of a four-way valve.

[0129] For the description of Figure 8 The description of S201 shown in the above embodiments can refer to the description of step S101, which will not be repeated here.

[0130] S202, in the case that the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the second working state, the controller controls the expansion valve to be closed and controls the compressor to operate at a target frequency.

[0131] It can be understood that, in the case that the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the second working state, it represents that the outdoor environment is a low-temperature environment, and the air conditioning system needs to be started for heating in the low-temperature environment. Therefore, the controller controls the outdoor expansion valve to be closed and controls the compressor to operate at a target frequency.

[0132] It can be understood that, in the case that the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the second working state, it represents that the outdoor environment is a low-temperature environment, and the air conditioning system needs to be started for heating in the low-temperature environment. Therefore, the controller controls the outdoor expansion valve to be closed and controls the compressor to operate at a target frequency.

[0133] In some embodiments, the controller controls the compressor to operate at a target frequency, which can compress the refrigerant flowing into the compressor and discharge the high-temperature and high-pressure gaseous refrigerant obtained by compression, so that the compressor establishes a certain superheat degree.

[0134] S203, in the case that the suction pressure of the compressor is lower than a preset pressure threshold, the controller controls the bypass valve to be opened.

[0135] In some embodiments, when the controller detects that the suction pressure of the compressor is lower than a preset pressure threshold, the controller controls the bypass valve to be opened. When the bypass valve is opened, the bypass branch is connected, and part of the high-temperature and high-pressure gaseous refrigerant discharged from the compressor can be merged with the refrigerant flowing to the gas-liquid separator. After the high-temperature and high-pressure gaseous refrigerant is merged, it enters the gas-liquid separator, evaporates the liquid refrigerant in the gas-liquid separator into gaseous refrigerant, and then flows into the compressor again. The refrigerant between the compressor and the gas-liquid separator forms an internal circulation, so that a small amount of liquid refrigerant exists in the gas-liquid separator.

[0136] S204, in the case that the discharge superheat degree of the compressor increases to a first superheat degree threshold, the controller controls the outdoor fan to operate at a target speed.

[0137] In some embodiments, the controller controls the compressor to operate at a target frequency, which gradually increases the discharge superheat degree and improves the stability of the compressor. When it is detected that the discharge superheat degree of the compressor reaches a first superheat degree threshold, the controller controls the outdoor fan to operate at a target speed. The outdoor fan operating at a target speed can improve the heat exchange efficiency between the outdoor heat exchanger and the outdoor environment, thereby improving the evaporation rate of the liquid refrigerant in the outdoor heat exchanger into gaseous refrigerant and reducing the content of the liquid refrigerant in the outdoor heat exchanger.

[0138] S205, in the case that the discharge superheat degree of the compressor increases to a second superheat degree threshold, the controller controls the expansion valve to be opened to a preset initial opening degree.

[0139] The second superheat threshold and the preset initial opening degree can be preset when the air conditioning system is manufactured, for example, the second superheat threshold is 10℃, and the initial preset opening degree is 8% of the maximum opening degree.

[0140] It can be understood that when the controller detects that the compressor discharge superheat reaches the second superheat threshold, the time consumed in this process is relatively long, the liquid refrigerant in the outdoor heat exchanger has been evaporated into gaseous refrigerant, and the liquid refrigerant in the gas-liquid separator has also been evaporated into gaseous refrigerant. At this time, the expansion valve is opened to the preset initial opening degree, and a small amount of liquid refrigerant existing in the outdoor heat exchanger will enter the gas-liquid separator and will not enter the compressor. In addition, after the expansion valve is opened, the refrigerant flow resistance is reduced, the refrigerant flow of the air conditioning system is large, the refrigerant flow entering the compressor is increased, which is conducive to improving the compressor discharge superheat.

[0141] S206, the starting control end condition is reached, and the air conditioning system heating starting is completed, and the starting control ends.

[0142] For the description of step S206, reference can be made to the description of step S105 described above, which will not be repeated here.

[0143] Based on Figure 8 The embodiments of the application at least have the following beneficial effects: The air conditioning system and the control method thereof provided by the embodiments of the application, when the controller detects that the outdoor environment temperature is lower than the preset temperature and the four-way valve is in the open state, the compressor is controlled to operate at a target frequency to improve the superheat of the compressor. When the suction pressure of the compressor is detected to be lower than the pressure threshold, the bypass valve is opened to connect the bypass branch. At this time, a part of the high-temperature and high-pressure gaseous refrigerant in the compressor can be diverted to enter the gas-liquid separator through the bypass branch, so that the liquid refrigerant in the gas-liquid separator is evaporated into gaseous refrigerant and then enters the compressor, and the refrigerant between the compressor and the gas-liquid separator forms an internal circulation. When the discharge superheat of the compressor is detected to reach the first preset threshold, the outdoor fan is controlled to operate at a target speed to improve the heat exchange rate of the outdoor heat exchanger, so that the liquid refrigerant in the outdoor heat exchanger is quickly evaporated into gaseous refrigerant to reduce the content of the liquid refrigerant in the outdoor heat exchanger. When the compressor reaches the second superheat threshold, the compressor has established a certain superheat, and only a small amount of liquid refrigerant exists in the outdoor heat exchanger. At this time, the expansion valve is opened, the liquid refrigerant enters the gas-liquid separator, and the gaseous refrigerant enters the compressor, thereby reducing the content of the liquid refrigerant in the air conditioning system. When the gas-liquid separator is not large enough, the liquid refrigerant can be prevented from entering the compressor during the heating starting process, thereby reducing the probability of damage to the compressor during the heating starting of the air conditioning system.

[0144] The above embodiments focus on the description of the outdoor environment temperature being lower than the preset temperature and the four-way valve being in the open state in the air conditioning system and the control method thereof provided by the embodiments of the present application. In some embodiments, the embodiments of the present application provide a description of the outdoor environment temperature being higher than the preset temperature and the four-way valve being in the closed state, as shown in FIG. 30. Figure 9 The method further includes the following steps:

[0145] S301, in response to a heating start instruction of the air conditioning system, acquiring an outdoor environment temperature and a working state of a four-way valve.

[0146] For the description of S301 as shown in FIG. 3, reference can be made to the description of step S101 above, which will not be repeated here. Figure 9

[0147] S302, in the case that the outdoor environment temperature is higher than the preset temperature and the four-way valve is in the first working state, controlling the outdoor expansion valve to open to a preset initial opening degree, controlling the compressor to operate at a target frequency, and controlling the bypass valve to close.

[0148] It can be understood that in the case that the outdoor environment temperature is higher than the preset temperature and the four-way valve is in the first working state, it represents that the outdoor environment is a high-temperature environment, and the air conditioning system needs to be started for heating in a low-temperature environment. Based on this, the controller controls the outdoor expansion valve to open to a preset opening degree, controls the compressor to operate at a target frequency, and controls the bypass valve to close.

[0149] It can be understood that the controller controls the expansion valve to open to a preset opening degree, so that the refrigerant flow path resistance of the outdoor expansion valve is increased, and the refrigerant circulation amount is reduced, so that after the four-way valve is switched to the second working state, it can be closed in time and the liquid refrigerant entering the compressor is reduced.

[0150] For example, when the expansion valve is controlled to open, the opening degree of the expansion valve can be adjusted to the maximum opening degree.

[0151] In some embodiments, controlling the compressor to operate at a target frequency can compress the refrigerant flowing through the outdoor expansion valve, and then discharge the high-temperature and high-pressure gaseous refrigerant obtained by compression. After the compressor discharges the high-temperature and high-pressure gaseous refrigerant, the exhaust pressure on the exhaust side of the compressor increases, the suction pressure on the suction side of the compressor remains unchanged, and therefore the pressure difference between the exhaust side and the suction side of the compressor increases with the increase of the working time of the compressor. The exhaust side of the compressor is connected to one oil port of the four-way valve, and the suction side of the compressor is connected to another oil port of the four-way valve. The pressure difference between the exhaust side and the suction side of the compressor, that is, the pressure difference between the two sides of the four-way valve.

[0152] ​In some embodiments, if the controller detects that the bypass valve is in the open state, the bypass valve is controlled to be closed, and if the controller detects that the bypass valve is in the closed state, the bypass valve is controlled to remain in the closed state. When the bypass valve is closed, the bypass branch is disconnected, and the high-temperature and high-pressure gaseous refrigerant discharged from the compressor is not divided, thereby preventing the pressure difference between the discharge side and the suction side of the compressor from decreasing.

[0153] S303, when the reversing condition of the four-way valve is met, the four-way valve is controlled to switch from the first working state to the second working state.

[0154] For the description of the reversing condition of the four-way valve, reference can be made to the description of the reversing condition of the four-way valve in step S103 described above, which will not be repeated here.

[0155] In some embodiments, after the controller detects that the pressure difference on both sides of the four-way valve reaches the reversing pressure difference, the four-way valve is controlled to switch from the first working state to the second working state, i.e., the four-way valve is controlled to reverse. The second working state is the open state, i.e., the four-way valve is switched from the closed state to the open state. After the four-way valve is switched to the open state, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor enters the indoor heat exchanger through the four-way valve, and the high-temperature and high-pressure gaseous refrigerant is condensed and releases heat in the indoor heat exchanger. At this time, the air conditioning system enters the heating mode.

[0156] S304, after the four-way valve is switched to the second working state, the outdoor fan is controlled to operate at a target speed, the opening degree of the expansion valve is controlled based on the superheat degree of the discharge of the compressor, and the opening and closing of the bypass valve is controlled based on the suction pressure of the compressor.

[0157] In some embodiments, after the four-way valve is opened, the air conditioning system enters the heating mode, and the controller controls the outdoor fan to operate at a target speed to improve the heat exchange efficiency between the outdoor heat exchanger and the outdoor environment, thereby increasing the rate of liquid refrigerant in the outdoor heat exchanger absorbing heat and evaporating into gaseous refrigerant, and increasing the refrigerant content circulating in the air conditioning system.

[0158] For example, the target speed is determined by the outdoor environment temperature, for example, the target speed is negatively correlated with the outdoor environment temperature, that is, the lower the outdoor environment temperature, the faster the outdoor fan speed; the higher the outdoor environment temperature, the slower the outdoor fan speed.

[0159] Optionally, as shown in Figure 10 The above step S304 can be specifically implemented as the following steps:

[0160] S3041, when the suction pressure of the compressor is lower than a preset pressure threshold, the bypass valve is controlled to be opened.

[0161] For the description of S3041, reference can be made to the description of step S1041 described above, which will not be repeated here.

[0162] S3042, Control the expansion valve to open to the preset initial opening degree.

[0163] In some embodiments, after the four-way valve opens, the controller controls the expansion valve to open to a preset opening degree. In high-temperature environments, the expansion valve opens to the preset opening degree, allowing refrigerant to circulate in the air conditioning system, enabling the compressor to quickly build up superheat. Once the compressor has built up a certain superheat degree, only gaseous refrigerant enters the compressor, preventing liquid refrigerant from entering and thus preventing damage to the compressor due to liquid compression.

[0164] The preset initial opening degree can be set at the factory when the air conditioning system leaves the factory. For example, the initial preset opening degree is 8% of the maximum opening degree.

[0165] S305. The start-up control termination condition has been met, the air conditioning system heating start-up is complete, and the start-up control ends.

[0166] Regarding Figure 9 The description of step S305 shown can be referred to the description of step S105 above, and will not be repeated here.

[0167] based on Figure 9 The illustrated embodiments offer at least the following beneficial effects: This application provides an air conditioning system and its control method. When the controller detects that the outdoor ambient temperature is higher than a preset temperature and the four-way valve is closed, it controls the compressor to operate at a target frequency. The compressor's discharge side has high discharge pressure and is connected to one port of the four-way valve, while the compressor's suction side has low suction pressure and is connected to the other port of the four-way valve, creating a pressure difference between the two ports. When the pressure difference between the two ports reaches the reversing condition, the four-way valve is switched to the open state. After the four-way valve is switched to the open state, the outdoor fan is controlled to operate at the target speed, improving the heat exchange efficiency of the outdoor heat exchanger. This increases the amount of gaseous refrigerant flowing in the air conditioning system and reduces the amount of liquid refrigerant. Simultaneously, the expansion valve is controlled to open to a preset initial opening, increasing the refrigerant flow rate in the air conditioning system, allowing the compressor to quickly establish superheat. After the compressor establishes a certain discharge superheat, the compressor's stability is improved, and since there is only a small amount of liquid refrigerant in the air conditioning system, liquid refrigerant will not enter the compressor, preventing compressor damage.

[0168] The above embodiments focus on the description of an air conditioning system and control method provided in this application regarding an outdoor ambient temperature higher than a preset temperature and a four-way valve in a closed state. In some embodiments, the description of an outdoor ambient temperature higher than a preset temperature and a four-way valve in an open state is provided in this application, such as... Figure 11 As shown, the method also includes the following steps:

[0169] S401, in response to a heating start instruction of the air conditioning system, acquire an outdoor environment temperature and a working state of a four-way valve.

[0170] Regarding the description of S401 shown in the above, the description of step S101 can be referred to, and will not be repeated here. Figure 11

[0171] S402, in the case that the outdoor environment temperature is higher than the preset temperature and the four-way valve is in the second working state, control the outdoor fan to run at a target speed for a first preset time length.

[0172] It can be understood that in the case that the outdoor environment temperature is higher than the preset temperature and the four-way valve is in the second working state, it represents that the outdoor environment is a high-temperature environment, and the air conditioning system needs to start heating in a high-temperature environment. Therefore, the controller controls the outdoor fan to run at a target speed for a first preset time length.

[0173] It can be understood that the controller controls the outdoor fan to run at a target speed for a first preset time length, which improves the heat exchange efficiency between the outdoor heat exchanger and the outdoor environment, and further improves the rate of liquid refrigerant in the outdoor heat exchanger absorbing heat and evaporating into gaseous refrigerant, so that the refrigerant flow in the air conditioning system increases.

[0174] The first preset time length can be set at the factory, for example, the first preset time length is 10 seconds.

[0175] It can be understood that the refrigerant flow in the air conditioning system increases, and the refrigerant flow into the compressor also increases, so that the compressor can quickly establish the superheat degree.

[0176] S403, control the compressor to run at a target frequency.

[0177] In some embodiments, the controller detects that the outdoor environment is a high-temperature environment through the temperature sensor, and detects that the working state of the four-way valve is an open state. The compressor is controlled to run at a target frequency. After the compressor runs and discharges high-temperature and high-pressure gaseous refrigerant, the exhaust pressure of the compressor increases, and the exhaust superheat degree of the compressor also increases, so that the compressor establishes a certain exhaust superheat degree.

[0178] S404, control the opening degree of the expansion valve based on the exhaust superheat degree of the compressor, and control the opening and closing of the bypass valve based on the suction pressure of the compressor.

[0179] In some embodiments, after the compressor establishes the exhaust superheat degree, only gaseous refrigerant enters the compressor. The opening degree of the expansion valve is controlled based on the exhaust superheat degree of the compressor, so that the refrigerant flow in the air conditioning system increases, the refrigerant flow into the compressor also increases, the compressor quickly establishes the superheat degree, and the stability of the compressor is improved. ​

[0180] In some embodiments, when the controller detects that the compressor's suction pressure is lower than a preset pressure threshold via a second pressure sensor, it controls the bypass valve to open. After the bypass valve opens, the bypass branch is connected, allowing a portion of the high-temperature, high-pressure gaseous refrigerant discharged from the compressor to flow out and merge with the refrigerant flowing towards the gas-liquid separator. After merging, the high-temperature, high-pressure gaseous refrigerant enters the gas-liquid separator, evaporating the liquid refrigerant there into gaseous refrigerant, thereby increasing the refrigerant flow rate into the compressor.

[0181] S405. The start-up control termination condition has been met, the air conditioning system heating start-up is complete, and the start-up control ends.

[0182] Regarding Figure 11 The description of S405 shown can be referred to the description of S105 above, and will not be repeated here.

[0183] based on Figure 11 The illustrated embodiments offer at least the following beneficial effects: This application provides an air conditioning system and its control method. When the controller detects that the outdoor ambient temperature is higher than a preset temperature and the four-way valve is open, it controls the outdoor fan to operate at a target speed, improving the heat exchange efficiency between the outdoor heat exchanger and the outdoor environment. Consequently, the amount of gaseous refrigerant flowing through the air conditioning system increases, while the amount of liquid refrigerant decreases. During the process of controlling the compressor to operate at a target frequency, after the high-temperature, high-pressure gaseous refrigerant is discharged, the compressor's discharge pressure increases, leading to an increase in the compressor's discharge superheat. The opening of the expansion valve is controlled based on the discharge superheat. When the discharge superheat is low, the expansion valve opening is increased, increasing the refrigerant flow rate through the air conditioning system, which in turn increases the refrigerant flow rate into the compressor, allowing the compressor to establish a higher discharge superheat. Once the compressor establishes a certain discharge superheat, the compressor's stability is improved. Furthermore, since there is only a small amount of liquid refrigerant in the air conditioning system, liquid refrigerant will not enter the compressor, preventing compressor damage.

[0184] The following example illustrates a control method for an air conditioning system provided in this application. Figure 12 As shown, after the user controls the air conditioning system to start heating, the controller first determines whether the outdoor ambient temperature is lower than the preset temperature. If the outdoor ambient temperature is lower than the preset temperature, it determines whether the four-way valve should be opened or closed.

[0185] When the four-way valve is in the open state, the controller controls the expansion valve to open at a preset opening degree, controls the compressor to run at a target frequency, controls the outdoor fan to be closed, and controls the bypass valve to be closed. After the four-way valve is opened, the compressor is controlled to run at the target frequency, the expansion valve is controlled to be closed, the bypass valve is controlled according to the suction pressure, and the outdoor fan is controlled to be closed. When the exhaust gas superheat is greater than 5℃, the outdoor fan is controlled to run at a target speed, and the compressor, the bypass valve and the expansion valve are kept in the original state. When the exhaust gas superheat is greater than 10℃, the expansion valve is controlled to open to a preset initial opening degree, and the compressor, the outdoor fan and the bypass valve are kept in the original state. When the start-up exit condition is reached, the start-up control ends. When the four-way valve is in the closed state, the controller controls the expansion valve to be closed, controls the compressor to run at a target frequency, controls the outdoor fan to be closed, and controls the bypass valve to be closed. When the exhaust gas superheat is greater than 5℃, the outdoor fan is controlled to run at a target speed, and the compressor, the bypass valve and the expansion valve are kept in the original state. When the exhaust gas superheat is greater than 10℃, the expansion valve is controlled to open to a preset initial opening degree, and the compressor, the outdoor fan and the bypass valve are kept in the original state. When the start-up exit condition is reached, the start-up control ends.

[0186] When the outdoor ambient temperature is greater than a preset temperature, it is also determined whether the four-way valve is open or closed. When the four-way valve is in the open state, the compressor is controlled to run at a target frequency, the expansion valve is controlled to open at a preset opening degree, the outdoor fan is controlled to be closed, and the bypass valve is controlled to be closed. After the four-way valve is opened, the compressor is controlled to run at the target frequency, the expansion valve is controlled according to the exhaust gas superheat, the outdoor fan is controlled to run at a target speed, and the bypass valve is controlled according to the suction pressure. When the start-up exit condition is reached, the start-up control ends.

[0187] When the four-way valve is in the open state, the outdoor fan is controlled to run at a target speed, the compressor is controlled to run at a target frequency, the expansion valve is controlled according to the exhaust gas superheat, and the bypass valve is controlled according to the suction pressure. When the start-up exit condition is reached, the start-up control ends.

[0188] It can be seen that the above mainly introduces the scheme provided by the embodiments of the present application from the perspective of method. In order to realize the above functions, the embodiments of the present application provide corresponding hardware structures and / or software modules for executing various functions. Those skilled in the art should easily realize that the modules and algorithm steps of the examples described in combination with the embodiments disclosed in the present text can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is realized in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0189] The embodiments of the present application can divide the functional modules of the controller according to the above method examples. For example, each functional module can be divided according to each function, or two or more functions can be integrated in one processing module. The integrated module can be realized in the form of hardware or in the form of a software functional module. Optionally, the division of the modules in the embodiments of the present application is illustrative, and is only a logical functional division. In actual implementation, another division mode can be used.

[0190] The embodiments of the present application also provide a hardware structure diagram of a controller, as shown in Figure 13 The controller 3000 includes a processor 3001, and optionally, a memory 3002 and a communication interface 3003 connected to the processor 3001. The processor 3001, the memory 3002 and the communication interface 3003 are connected through a bus 3004.

[0191] The processor 3001 can be a central processing unit (CPU), a general processor network processor (NP), a digital signal processing (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD) or any combination thereof. The processor 3001 can also be any other device having a processing function, such as a circuit, a device or a software module. The processor 3001 can also include multiple CPUs, and the processor 3001 can be a single-CPU processor or a multi-CPU processor. The processor herein can refer to one or more devices, circuits or processing cores for processing data (for example, computer program instructions).

[0192] The memory 3002 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage or other magnetic storage devices, or any other medium capable of storing desired program code in the form of instructions or data structures and that can be accessed by a computer, without any limitation on the present embodiments. The memory 3002 can exist independently or be integrated with the processor 3001. The memory 3002 can contain computer program code. The processor 3001 is configured to execute the computer program code stored in the memory 3002, thereby implementing the method for controlling an air conditioning system according to the embodiments.

[0193] The communication interface 3003 can be configured to communicate with other devices or communication networks (e.g., Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.). The communication interface 3003 can be a module, a circuit, a transceiver, or any device capable of communication.

[0194] The bus 3004 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 3004 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 13 Only one thick line is used in the figure to represent the bus, but it does not mean that there is only one bus or only one type of bus.

[0195] The embodiments of the present application also provide a computer readable storage medium, which includes computer execution instructions. When the computer execution instructions run on a computer, the computer is caused to execute the method for controlling an air conditioning system according to the above embodiments.

[0196] The embodiment of the present application further provides a computer program product, which can be directly loaded into a memory and contains software codes, and the computer program product can realize the control method of the air conditioning system provided by the above embodiment after being loaded and executed by a computer.

[0197] Those skilled in the art should understand that, in one or more examples described above, the functions described by the present application can be realized by hardware, software, firmware or any combination thereof. When realized by software, the functions can be stored in a computer readable medium or transmitted as one or more instructions or codes on a computer readable medium. The computer readable medium includes a computer storage medium and a communication medium, wherein the communication medium includes any medium that facilitates the transmission of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0198] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional modules is taken as an example, and in actual application, the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0199] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative, for example, the division of the modules or units is only a logical function division, and actual implementation can have another division manner. For example, a plurality of units or components can be combined or integrated into another device, or some features can be omitted or not executed. In addition, the coupling or direct coupling or communication connection between the units or components shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms. The units described as separate components can be or can not be physically separated, and the components shown as units can be one physical unit or a plurality of physical units, that is, can be located in one place, or can be distributed in a plurality of different places. According to actual needs, some or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0200] In addition, each function unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software function unit. When the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application essentially or said part that contributes to the prior art or all or part of the technical solutions can be embodied in the form of a software product. The software product is stored in a storage medium, including a plurality of instructions to make a device (which can be a single-chip microcomputer, a chip, etc.) or a processor execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk, and various storage medium that can store program codes.

[0201] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An air conditioning system, characterized in that, include: The refrigerant circulation loop allows the refrigerant to circulate within a circuit consisting of the compressor, condenser, expansion valve, evaporator, four-way valve, and gas-liquid separator. A compressor is used to compress low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas and discharge it to the condenser. An outdoor heat exchanger and an indoor heat exchanger, one of which functions as a condenser and the other as an evaporator; A four-way valve is used to control the refrigerant flow direction in the refrigerant circuit; when the four-way valve is in the first working state, the outdoor heat exchanger operates as a condenser; when the four-way valve is in the second working state, the outdoor heat exchanger operates as an evaporator. A bypass branch is provided between the inlet of the gas-liquid separator and the outlet of the compressor, for diverting a portion of the refrigerant from the refrigerant flowing from the compressor to the condenser and merging it with the refrigerant flowing to the inlet of the gas-liquid separator; A bypass valve is installed on the bypass branch and is used to control the opening and closing of the bypass branch; and a controller, the controller being configured to: In response to the heating start command of the air conditioning system, the outdoor ambient temperature and the working status of the four-way valve are obtained; When the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the first working state, the expansion valve is controlled to open to the preset initial opening degree, the compressor is controlled to increase its frequency to the target frequency, and the bypass valve is controlled to close. When the switching conditions of the four-way valve are met, the four-way valve is controlled to switch from the first working state to the second working state, and the expansion valve is controlled to close at the same time. After the four-way valve switches to the second working state, the opening degree of the expansion valve is controlled based on the exhaust superheat of the compressor, and the opening and closing of the bypass valve is controlled based on the suction pressure of the compressor. The air conditioning system also includes: An outdoor fan is used to dissipate heat from the outdoor heat exchanger; The controller is also configured to: When the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the first working state, the outdoor fan is controlled to stop operating. After the four-way valve switches to the second working state, when the exhaust superheat of the compressor is lower than the first preset superheat, the outdoor fan is controlled to stop operating. When the superheat of the compressor's exhaust reaches the first superheat threshold, the outdoor fan is controlled to operate at the target speed.

2. The air conditioning system according to claim 1, characterized in that, The controller is configured to control the opening degree of the expansion valve based on the discharge superheat of the compressor after the four-way valve switches to the second operating state, including: After the four-way valve switches to the second working state, when the exhaust superheat of the compressor is lower than the second superheat threshold, the expansion valve is controlled to remain closed, and the second superheat threshold is higher than the first superheat threshold. When the superheat of the compressor's exhaust gas rises to the second superheat threshold, the expansion valve is controlled to open to a preset initial opening degree.

3. The air conditioning system according to claim 2, characterized in that, The controller is also configured to: After the start-up control termination conditions are met, the opening of the expansion valve is adjusted so that the discharge superheat of the compressor reaches the target discharge superheat, or the suction superheat of the compressor reaches the target suction superheat.

4. The air conditioning system according to any one of claims 1 to 2, characterized in that, The controller is configured to control the opening and closing of the bypass valve based on the compressor's suction pressure after the four-way valve switches to the second operating state, including: After the four-way valve switches to the second working state, when the suction pressure of the compressor is lower than the preset pressure threshold, the bypass valve is controlled to open. After the compressor's suction pressure reaches a preset pressure threshold, the bypass valve is controlled to close.

5. The air conditioning system according to claim 4, characterized in that, The controller is also configured to: After the start-up control termination condition is met, the bypass valve is controlled to close.

6. The air conditioning system according to claim 3 or 5, characterized in that, The start-up control termination condition includes any one of the following: The bypass valve is open for a preset duration; or, When the superheat of the compressor's exhaust reaches the third superheat threshold, the third superheat threshold is greater than the second superheat threshold.

7. The air conditioning system according to claim 1, characterized in that, The controller is also configured to: When the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the second working state, the expansion valve is controlled to close, and the compressor is controlled to operate at the target frequency. The opening degree of the expansion valve is controlled based on the exhaust superheat of the compressor, and the opening and closing of the bypass valve is controlled based on the suction pressure of the compressor.

8. The air conditioning system according to claim 7, characterized in that, The air conditioning system also includes: An outdoor fan is used to dissipate heat from the outdoor heat exchanger; The controller is also configured to: When the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the second working state, the outdoor fan is controlled to stop operating. When the superheat of the compressor's exhaust reaches the first superheat threshold, the outdoor fan is controlled to operate at the target speed.

9. A control method for an air conditioning system, characterized in that, The method, applied to the air conditioning system of any one of claims 1-8, comprises: In response to the heating start command of the air conditioning system, the outdoor ambient temperature and the working status of the four-way valve are obtained; When the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the first working state, the expansion valve is controlled to open to the preset initial opening degree, the compressor is controlled to increase its frequency to the target frequency, and the bypass valve is controlled to close. When the switching conditions of the four-way valve are met, the four-way valve is controlled to switch from the first working state to the second working state, and the expansion valve is controlled to close at the same time. After the four-way valve switches to the second working state, the opening degree of the expansion valve is controlled based on the exhaust superheat of the compressor, and the opening and closing of the bypass valve is controlled based on the suction pressure of the compressor. When the outdoor ambient temperature is lower than the preset temperature and the four-way valve is in the first working state, the outdoor fan is controlled to stop operating. After the four-way valve switches to the second working state, when the exhaust superheat of the compressor is lower than the first preset superheat, the outdoor fan is controlled to stop operating. When the superheat of the compressor's exhaust reaches the first superheat threshold, the outdoor fan is controlled to operate at the target speed.

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