An air conditioning system and its control method

Abstract

This application provides an air conditioning system and its control method, relating to the field of air conditioning technology, for preventing oil blockage in air conditioning systems and improving the reliability of air conditioning system operation. The air conditioning system includes: a controller configured to: after the air conditioning system has entered heating mode for a first preset time, acquire a first outdoor ambient temperature value, a first outdoor coil temperature value, a compressor discharge pressure value, and a compressor suction pressure value; and, under the condition that a first preset condition is met, control a first solenoid valve to open and control a second solenoid valve to close; the first preset condition includes the outdoor coil temperature value being below a temperature between a first temperature threshold and a first preset temperature value, the temperature difference between the outdoor ambient temperature value and the outdoor coil temperature value being above a second preset temperature value, and the pressure ratio between the compressor discharge pressure value and the compressor suction pressure value being below a preset pressure ratio.

Description

Technical Field

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

[0002] Currently, flammable refrigerants such as R290 are widely used in air conditioning systems due to their near-zero pollution advantage. However, because flammable refrigerants are flammable and explosive, their charge in air conditioning systems is severely limited. Furthermore, to achieve higher heating capacity, air conditioning systems typically increase compressor displacement. With extremely low refrigerant charges and high compressor displacement, the compressor's lubricating oil can easily become clogged with flocculent material during heating or defrosting operation, leading to oil blockage. This prevents the flammable refrigerant and lubricating oil from returning to the compressor, causing it to run idle and seriously threatening the reliability of the air conditioning system.

[0003] Currently, oil blockage in air conditioning systems is addressed by adjusting the opening of the electronic expansion valve or the operating frequency of the compressor. However, both methods are prone to failure under extreme conditions, leading to poor system reliability. Therefore, preventing oil blockage and improving the reliability of air conditioning systems is an urgent problem to be solved. Summary of the Invention

[0004] This application provides an air conditioning system and its control method to prevent oil blockage in the air conditioning system and improve the reliability of the air conditioning system operation.

[0005] In a first aspect, an air conditioning system is provided, comprising: a refrigerant circulation loop, wherein the refrigerant circulates in a loop consisting of a compressor, an outdoor heat exchanger, an indoor heat exchanger, and a four-way valve;

[0006] An outdoor heat exchanger and an indoor heat exchanger, one of which functions as a condenser and the other as an evaporator;

[0007] 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.

[0008] A four-way valve is used to control the flow of refrigerant in a refrigerant circuit.

[0009] A sleeve-type throttle valve includes a valve core tube and a sleeve. The valve core tube is located inside the sleeve. One end of the sleeve is connected to the exhaust port of the compressor, and the other end is connected to the outdoor heat exchanger.

[0010] The first solenoid valve is installed in the first pipeline between the compressor and the sleeve-type throttle valve, and is used to control the connection and cut-off of the refrigerant flowing through the first pipeline;

[0011] The second solenoid valve is located in the second pipeline between the compressor and the four-way valve and is used to control the connection and disconnection of the refrigerant flowing through the second pipeline.

[0012] The first temperature sensor is used to detect the temperature value of the outdoor environment;

[0013] The second temperature sensor is used to detect the temperature value of the outdoor coil.

[0014] The first pressure sensor is located at the compressor's exhaust port and is used to detect the compressor's exhaust pressure value.

[0015] The second pressure sensor is located at the compressor's suction port and is used to detect the compressor's suction pressure value.

[0016] The controller is configured as follows:

[0017] After the air conditioning system has been in heating mode for a first preset time, the first outdoor ambient temperature value, the first outdoor coil temperature value, the compressor discharge pressure value, and the compressor suction pressure value are obtained.

[0018] Under the condition of meeting the first preset condition, the first solenoid valve is controlled to open and the second solenoid valve is controlled to close; the first preset condition includes the first temperature value of the outdoor coil being below the temperature value between the first temperature threshold and the first preset temperature value, the temperature difference between the first temperature value of the outdoor environment and the first temperature value of the outdoor coil being above the second preset temperature value, and the pressure ratio between the discharge pressure value of the compressor and the first suction pressure value of the compressor being below the preset pressure ratio.

[0019] The technical solution provided in this application provides at least the following beneficial effects: When the air conditioning system is in heating mode, under the condition of meeting the first preset condition, it means that the outdoor coil temperature of the air conditioning system is low and there is a possibility of frosting. At this time, the high-temperature and high-pressure refrigerant gas in the refrigerant circulation loop will condense after entering the indoor heat exchanger, resulting in a low refrigerant temperature, which in turn leads to a decrease in the temperature of the lubricating oil in the air conditioning system and an increase in the viscosity of the lubricating oil. Therefore, oil blockage may occur when the lubricating oil flows through the sleeve-type throttle valve. In this case, by controlling the first solenoid valve to open and the second solenoid valve to close, the high-temperature and high-pressure refrigerant gas discharged from the compressor outlet enters the sleeve-type throttle valve to heat the sleeve-type throttle valve, thereby increasing the temperature of the lubricating oil flowing through the sleeve-type throttle valve and reducing the viscosity of the lubricating oil, thereby preventing oil blockage in the air conditioning system and improving the reliability of the air conditioning system operation.

[0020] In some embodiments, the air conditioning system further includes: a heating belt disposed on the sleeve of a sleeve-type throttle valve for heating the sleeve-type throttle valve; and a controller further configured to: after controlling the air conditioning system to switch from heating mode to defrost mode for a second preset time, acquire a second suction pressure value of the compressor and a first operating power of the compressor; control a first solenoid valve to close and control a second solenoid valve to open if a second preset condition is met; the second preset condition includes that the second suction pressure value of the compressor is above a first pressure threshold and the first operating power of the compressor is above a first preset operating power; and control the heating belt to start working if the second preset condition is not met.

[0021] In some embodiments, the controller is configured to control the first solenoid valve to close and the second solenoid valve to open, and is further configured to: after a third preset time period following the control of the first solenoid valve to close and the control of the second solenoid valve to open, acquire a third temperature value of the outdoor coil; and if the third temperature value of the outdoor coil is detected to be above the temperature difference between the second temperature threshold and the third preset temperature value, control the first solenoid valve to open and control the second solenoid valve to close.

[0022] In some embodiments, the controller is further configured to: after a fourth preset time has elapsed since the air conditioning system switched from defrosting mode to heating mode, acquire the third suction pressure value of the compressor and the second operating power of the compressor; if a third preset condition is met, control the first solenoid valve to close and control the second solenoid valve to open, the third preset condition including the third suction pressure value of the compressor being above a first pressure threshold and the second operating power of the compressor being above a second preset operating power; if the third preset condition is not met, control the heating belt to start working.

[0023] In some embodiments, when the controller is configured to control the air conditioning system to switch from heating mode to defrost mode, it is specifically configured to: acquire a fourth temperature value of the outdoor coil when the air conditioning system is in heating mode; and control the air conditioning system to switch from heating mode to defrost mode when the fourth temperature value of the coil is detected to be below a third temperature threshold. When the controller is configured to control the air conditioning system to switch from defrost mode to heating mode, it is specifically configured to: acquire a fifth temperature value of the outdoor coil when the air conditioning system is in defrost mode; and control the air conditioning system to switch from defrost mode to heating mode when the fifth temperature value of the coil is detected to be above the fourth temperature threshold, wherein the fourth temperature threshold is above the third temperature threshold.

[0024] Secondly, a control method for an air conditioning system is provided. The method includes: after the air conditioning system has entered the heating mode for a first preset time, acquiring a first outdoor ambient temperature value, a first outdoor coil temperature value, a compressor discharge pressure value, and a compressor suction pressure value; and, under the condition that a first preset condition is met, controlling a first solenoid valve to open and controlling a second solenoid valve to close; the first preset condition includes the outdoor coil temperature value being below the temperature value between a first temperature threshold and a first preset temperature value, the temperature difference between the outdoor ambient temperature value and the outdoor coil temperature value being above the second preset temperature value, and the pressure ratio between the compressor discharge pressure value and the compressor suction pressure value being below a preset pressure ratio.

[0025] In some embodiments, after the air conditioning system switches from heating mode to defrost mode for a second preset time, the second suction pressure value of the compressor and the first operating power of the compressor are obtained; if the second preset condition is met, the first solenoid valve is controlled to close and the second solenoid valve is controlled to open; the second preset condition includes that the second suction pressure value of the compressor is above the first pressure threshold and the first operating power of the compressor is above the first preset operating power; if the second preset condition is not met, the heating belt is controlled to start working.

[0026] In some embodiments, after controlling the first solenoid valve to close and the second solenoid valve to open, the method further includes: after controlling the first solenoid valve to close and the second solenoid valve to open for a third preset time period, obtaining a third temperature value of the outdoor coil; and if the third temperature value of the outdoor coil is detected to be above the temperature difference between the second temperature threshold and the third preset temperature value, controlling the first solenoid valve to open and the second solenoid valve to close.

[0027] In some embodiments, after the air conditioning system switches from defrosting mode to heating mode for a fourth preset period of time, the third suction pressure value of the compressor and the second operating power of the compressor are obtained; if the third preset condition is met, the first solenoid valve is controlled to close and the second solenoid valve is controlled to open. The third preset condition includes that the third suction pressure value of the compressor is above the first pressure threshold and the second operating power of the compressor is above the second preset operating power; if the third preset condition is not met, the heating belt is controlled to start working.

[0028] In some embodiments, controlling the air conditioning system to switch from heating mode to defrost mode includes: when the air conditioning system is in heating mode, acquiring a fourth temperature value of the outdoor coil; when the fourth temperature value of the coil is detected to be below a third temperature threshold, controlling the air conditioning system to switch from heating mode to defrost mode; controlling the air conditioning system to switch from defrost mode to heating mode includes: when the air conditioning system is in defrost mode, acquiring a fifth temperature value of the outdoor coil; when the fifth temperature value of the outdoor coil is detected to be above the fourth temperature threshold, controlling the air conditioning system to switch from defrost mode to heating mode, wherein the fourth temperature threshold is above the third temperature threshold.

[0029] Thirdly, embodiments of this application provide a controller, including: one or more processors; one or more memories; wherein the one or more memories are used to store computer program code, the computer program code including computer instructions, and when the one or more processors execute the computer instructions, the controller executes a control method for an air conditioning system provided in the second aspect.

[0030] Fourthly, embodiments of this application provide a computer-readable storage medium including computer instructions that, when executed on a computer, cause the computer to perform a control method for an air conditioning system provided in the second aspect.

[0031] Fifthly, embodiments of the present invention provide a computer program product that can be directly loaded into a memory and contains software code. After being loaded and executed by a computer, the computer program product can realize the control method of an air conditioning system provided in the second aspect.

[0032] It should be noted that the aforementioned computer instructions may be stored, in whole or in part, on a computer-readable storage medium. This computer-readable storage medium may be packaged together with the controller's processor, or it may be packaged separately from the controller's processor; this application does not impose any limitations on this.

[0033] The beneficial effects described in aspects two through five of this application can be referred to the analysis of the beneficial effects of aspect one, and will not be repeated here. Attached Figure Description

[0034] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0035] Figure 1 This is a schematic diagram of the composition of an air conditioning system provided in an embodiment of this application;

[0036] Figure 2This application provides a schematic diagram of the structure of an air conditioning system according to an embodiment of the present application.

[0037] Figure 3 A schematic diagram of the structure of a sleeve-type throttle valve provided for an embodiment of this application;

[0038] Figure 4 A hardware configuration block diagram of an air conditioning system provided in an embodiment of this application;

[0039] Figure 5 This is a schematic diagram of another air conditioning system provided in an embodiment of this application;

[0040] Figure 6 A flowchart illustrating a control method for an air conditioning system provided in an embodiment of this application;

[0041] Figure 7 A flowchart illustrating another control method for an air conditioning system provided in an embodiment of this application;

[0042] Figure 8 A flowchart illustrating another control method for an air conditioning system provided in an embodiment of this application;

[0043] Figure 9 A flowchart illustrating another control method for an air conditioning system provided in an embodiment of this application;

[0044] Figure 10 This is a schematic diagram of the overall flow of a control method for an air conditioning system provided in an embodiment of this application;

[0045] Figure 11 This is a schematic diagram of the hardware structure of a controller provided in an embodiment of this application. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] Currently, with extremely low refrigerant charges such as R290 and high compressor discharge rates, air conditioning systems are prone to oil blockage during heating or defrosting operations. This can lead to the accumulation of flocculent material in the compressor's lubricating oil, clogging the throttling device and preventing the return of flammable refrigerant and lubricating oil to the compressor. This results in the compressor running dry, severely threatening the reliability of the air conditioning system. Current industry practices address oil blockage by controlling the electronic expansion valve or compressor frequency in the air conditioning system; however, these methods are prone to failure under extreme conditions and have poor adaptability.

[0052] Based on this, this application provides an air conditioning system and its control method. When the air conditioning system is in heating mode, it determines whether a first preset condition is met. If the first preset condition is met, it controls the first solenoid valve to open and the second solenoid valve to close. Since the first solenoid valve is located in the first pipeline between the compressor and the sleeve-type throttle valve, the controller controls the first solenoid valve to open and the second solenoid valve to close, allowing the high-temperature, high-pressure refrigerant gas generated by the compressor to be discharged through the first pipeline to the sleeve-type throttle valve, heating the sleeve-type throttle valve. This increases the temperature of the lubricating oil flowing through the sleeve-type throttle valve and reduces its viscosity, thereby preventing oil blockage in the air conditioning system and improving the reliability of the air conditioning system operation.

[0053] To facilitate understanding, we will first provide a brief introduction and explanation of some terms or basic concepts of technology involved in the embodiments of this application.

[0054] Refrigerant: A substance that easily absorbs heat and turns into a gas, and easily releases heat and turns into a liquid. In air conditioning systems, heat energy is transferred through the evaporation and condensation of the refrigerant.

[0055] Heating Mode: The air conditioning system's compressor draws the low-temperature, low-pressure gaseous refrigerant, evaporated in the evaporator, into the compressor chamber, compressing it into a high-temperature, high-pressure gaseous refrigerant, which then enters the condenser. In the condenser, the high-temperature, high-pressure gaseous refrigerant condenses into a high-temperature, high-pressure liquid refrigerant. After passing through a throttling element such as an electronic expansion valve, it becomes a low-temperature, low-pressure liquid refrigerant, which then evaporates in the evaporator before finally returning to the compressor, completing the entire refrigeration cycle. In heating mode, the outdoor heat exchanger functions as the evaporator, and the indoor heat exchanger functions as the condenser.

[0056] 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 and a controller 12. Figure 1 (Not shown in the image), Indoor unit 13.

[0057] Outdoor unit 11 is usually installed outdoors and is used for heat exchange with the outdoor environment.

[0058] Indoor unit 13 is usually installed indoors to exchange heat with the indoor environment to achieve the effect of heating or cooling.

[0059] There is a pipe connection between the outdoor unit 11 and the indoor unit 13. 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.

[0060] In some embodiments, controller 12 refers to a device that can generate operation control signals based on instruction opcodes and timing signals to instruct the air conditioning system to execute control commands. Exemplarily, the controller can be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The controller can also be other devices with processing functions, such as circuits, devices, or software modules; this application embodiment does not impose any limitations on this.

[0061] In addition, the controller 12 can be used to control the operation of various components inside the air conditioning system 10 so that the various components of the air conditioning system 10 can operate to achieve the predetermined functions of the air conditioning system.

[0062] In some embodiments, the air conditioning system may also include a remote control, which may exist independently outside the air conditioning system and has several buttons on it, with different buttons that can adjust the status of the air conditioning system.

[0063] Figure 2 This is a schematic diagram of an air conditioning system provided in an embodiment of this application. Figure 2 As shown, the air conditioning system 10 includes a compressor 111, a four-way valve 112, an indoor heat exchanger 113, an outdoor heat exchanger 114, a sleeve-type throttle valve 115, a first solenoid valve 116, and a second solenoid valve 117.

[0064] In some embodiments, the air conditioning system 10 includes a refrigerant circulation loop, which allows refrigerant to circulate in a loop consisting of compressor 111, four-way valve 112, indoor heat exchanger 113, and outdoor heat exchanger 114.

[0065] In some embodiments, compressor 111 is connected to controller 12. Compressor 111 is used to compress low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas and discharge it to the condenser.

[0066] In some embodiments, compressor 111 may be a variable-capacity inverter compressor that performs inverter-based speed control.

[0067] In some embodiments, the four-way valve 112 is connected to the controller 12. The four-way valve 112 controls the refrigerant flow direction in the refrigerant circulation loop. The four-way valve 112 is a control valve with four ports, which are respectively connected to the compressor 111, the indoor heat exchanger 113, the outdoor heat exchanger 114, and the sleeve-type expansion valve 115. The four-way valve 112 is used to achieve mutual switching between defrosting and heating by changing the refrigerant flow direction in the system piping.

[0068] In some embodiments, the solenoid valve coil on the four-way valve is energized and in the open state. Under the magnetic force generated by the solenoid coil, the pilot slide valve overcomes the tension of the compression spring and moves to the right. High-pressure gas enters the capillary tube and then enters the left piston chamber. On the other hand, the gas in the right piston chamber is discharged. Due to the pressure difference between the two ends of the piston, the piston and the main slide valve move to the right, so that the exhaust pipe is connected to the indoor unit pipe, and the other two pipes are connected to form a heating cycle.

[0069] In some embodiments, the indoor heat exchanger 113 is connected to the controller 12. One end of the indoor heat exchanger 113 is connected to a four-way valve 112, and the other end is connected to a sleeve-type throttle valve 115. The indoor heat exchanger 113 is typically installed indoors for heat exchange with the indoor environment. In heating mode, the gaseous refrigerant in the indoor heat exchanger 113 releases heat and converts into liquid refrigerant, which then functions as a condenser.

[0070] In some embodiments, the outdoor heat exchanger 114 is connected to the controller 12. One end of the outdoor heat exchanger 114 is connected to a four-way valve 112, and the other end is connected to a sleeve-type throttle valve 115. The outdoor heat exchanger 114 is typically installed outdoors for heat exchange with the outdoor environment. In heating mode, the liquid refrigerant in the outdoor heat exchanger 114 absorbs heat and converts into gaseous refrigerant, functioning as an evaporator.

[0071] In some embodiments, a sleeve-type throttling valve 115 is disposed between the indoor heat exchanger 113 and the outdoor heat exchanger 114. Figure 3 This is a schematic diagram of a sleeve-type throttle valve provided in an embodiment of this application. The sleeve-type throttle valve 115 includes a valve core tube and a sleeve. The valve core tube is disposed inside the sleeve. One end of the sleeve is connected to the exhaust port of the compressor 111, and the other end is connected to the outdoor heat exchanger 114.

[0072] In some embodiments, a first solenoid valve 116 is disposed in a first pipeline between the compressor 111 and the sleeve-type throttle valve 115, and is used to control the connection and disconnection of the refrigerant flowing through the first pipeline.

[0073] In some embodiments, the second solenoid valve 117 is disposed in the second pipeline between the compressor 111 and the four-way valve 112, and is used to control the connection and disconnection of the refrigerant flowing through the second pipeline.

[0074] In some embodiments, the air conditioning system 10 may also include other components, such as Figure 4 The diagram shown is a hardware configuration block diagram of an air conditioning system provided in an embodiment of this application. Figure 4 As shown, the air conditioning system 10 may further include: a first temperature sensor 118, a second temperature sensor 119, a first pressure sensor 120, a second pressure sensor 121, a heating belt 122, a communicator 123, and a memory 124.

[0075] In some embodiments, the first temperature sensor 118 is connected to the controller 12 and can be installed on the outdoor unit 11 to detect the temperature value of the environment where the outdoor unit 11 is located and send the detected temperature value of the environment where the outdoor unit 11 is located to the controller 12.

[0076] In some embodiments, the second temperature sensor 119 is connected to the controller 12 and can be installed on the outdoor coil of the outdoor unit 11 to detect the temperature value of the outdoor coil of the outdoor unit 11 and send the detected temperature value of the outdoor coil of the outdoor unit 11 to the controller 12.

[0077] In some embodiments, the first pressure sensor 120 is connected to the controller 12 and is located at the exhaust port of the compressor 111 to detect the exhaust pressure value of the compressor and send the detected exhaust pressure value to the controller 12.

[0078] In some embodiments, the second pressure sensor 121 is connected to the controller 12 and is located at the suction port of the compressor 111 to detect the suction pressure value of the compressor and send the detected suction pressure value to the controller 12.

[0079] In some embodiments, a heating band 122 is disposed on the sleeve of the sleeve-type throttle valve 115 for heating the sleeve-type throttle valve 115.

[0080] For example, the heating band 122 can be wrapped around the sleeve of the sleeve-type throttle valve 115.

[0081] In some embodiments, the heating belt 122 is an explosion-proof heating belt.

[0082] In some embodiments, the communicator 123 is used to establish communication connections with other network entities, such as establishing communication connections with terminal devices. The communicator 123 may include a radio frequency (RF) module, a cellular module, a wireless fidelity (WIFI) module, and a GPS module, etc. Taking an RF module as an example, the RF module can be used for signal reception and transmission; specifically, it sends received information to the controller 12 for processing; additionally, it transmits signals generated by the controller 12. Typically, the RF circuit may include, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low-noise amplifier (LNA), a duplexer, etc.

[0083] The memory 124 can be used to store software programs and data. The controller 12 executes various functions of the air conditioning system 10 and performs data processing by running the software programs or data stored in the memory 124. The memory 124 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. The memory 124 stores the operating system that enables the air conditioning system 10 to run. In this application, the memory 124 may store the operating system and various application programs, and may also store code that executes the control method of the air conditioning system provided in the embodiments of this application.

[0084] Those skilled in the art will understand that Figure 4 The hardware structure shown does not constitute a limitation on the air conditioning system. The air conditioning system may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0085] The above Figure 2 The illustrated embodiment is based on an air conditioning system including a first solenoid valve and a second solenoid valve. In some embodiments, such as... Figure 5 The diagram shown is a structural schematic of another air conditioning system provided in an embodiment of this application. The air conditioning system 10 includes a compressor 111, a four-way valve 112, an indoor heat exchanger 113, an outdoor heat exchanger 114, and a sleeve-type throttle valve 115.

[0086] For descriptions of compressor 111, four-way valve 112, indoor heat exchanger 113, outdoor heat exchanger 114, and shell-and-tube throttle valve 115, please refer to the above. Figure 2 The corresponding descriptions in the text will not be repeated here.

[0087] Compared to Figure 2 The embodiment shown, Figure 5 The air conditioning system 10 shown does not include the first solenoid valve and the second solenoid valve. Understandably, when the first and second solenoid valves are absent from the refrigerant circulation loop, the high-temperature, high-pressure refrigerant gas generated by the compressor can continuously heat the sleeve-type throttle valve. By increasing the temperature inside the sleeve-type throttle valve, the viscosity of the lubricating oil inside the valve is reduced. This also prevents the refrigerant and lubricating oil from separating at low temperatures, thus preventing the lubricating oil from becoming more viscous and remaining inside the throttle valve core, effectively solving the oil blockage problem.

[0088] The embodiments provided in this application will now be described in detail with reference to the accompanying drawings.

[0089] This application provides a control method for an air conditioning system. The method is applied to a controller, which can be the aforementioned... Figure 4 The controller 12 shown is as follows: Figure 6 As shown, the method includes the following steps:

[0090] S101. After the air conditioning system has entered the heating mode for a first preset time, obtain the first outdoor ambient temperature value, the first outdoor coil temperature value, the compressor discharge pressure value, and the compressor suction pressure value.

[0091] In some embodiments, when a user needs to use the heating mode of the air conditioning system, the user can send a control command to the air conditioning system through a terminal device or the remote control of the air conditioning system to control the air conditioning system to enter the heating mode. Upon receiving the control command, the controller controls the air conditioning system to enter the heating mode in response to the control command.

[0092] In some embodiments, in order to ensure the stability of the acquired data, after the air conditioning system has entered the heating mode for a first preset time, the controller acquires the first temperature value of the outdoor environment through the first temperature sensor, acquires the first temperature value of the outdoor coil through the second temperature sensor, acquires the discharge pressure value of the compressor through the first pressure sensor, and acquires the first suction pressure value of the compressor through the second pressure sensor.

[0093] The first preset duration is set at the factory when the air conditioning system leaves the factory; for example, the first preset duration is 15 minutes.

[0094] S102. Under the condition that the first preset condition is met, control the first solenoid valve to open and control the second solenoid valve to close.

[0095] The first preset conditions include the outdoor coil's first temperature value being between and below the first temperature threshold and the first preset temperature value, the temperature difference between the outdoor environment's first temperature value and the outdoor coil's first temperature value being above the second preset temperature value, and the pressure ratio between the compressor's discharge pressure value and the compressor's first intake pressure value being below the preset pressure ratio.

[0096] The first temperature threshold, the first preset temperature value, the second preset temperature value, and the preset pressure ratio are all preset at the factory of the air conditioning system. For example, the first temperature threshold is -8℃, the first preset temperature value is -6℃, the second preset temperature value is 15℃, and the preset pressure ratio is 6.5.

[0097] In some embodiments, the setting of the first temperature threshold is related to the outdoor coil temperature when the air conditioning system enters the defrost mode, and the outdoor coil temperature when the air conditioning system enters the defrost mode can be used as the first temperature threshold.

[0098] For example, suppose the first preset duration is 15 minutes, the first temperature threshold is -8℃, the first preset temperature is -6℃, the second preset temperature is 15℃, and the preset pressure ratio is 6.5. After the air conditioning system has been running in heating mode for 15 minutes, if the first temperature of the outdoor coil is detected to be -9℃, the first temperature of the outdoor environment is detected to be 4℃, and the pressure ratio between the compressor's discharge pressure and the compressor's first suction pressure is 3, then the air conditioning system meets the first preset conditions in heating mode. In this case, the first solenoid valve is opened, and the second solenoid valve is closed, thereby preventing oil blockage in the air conditioning system and improving the reliability of the air conditioning system operation.

[0099] based on Figure 6 The illustrated embodiment provides at least the following beneficial effects: When the air conditioning system is in heating mode, under the condition of meeting the first preset condition, the outdoor coil temperature of the air conditioning system is low, and there is a possibility of frosting. At this time, the high-temperature and high-pressure refrigerant gas in the refrigerant circulation loop will condense after entering the indoor heat exchanger, resulting in a low refrigerant temperature. Consequently, the temperature of the lubricating oil in the air conditioning system will decrease, and the viscosity of the lubricating oil will increase. Therefore, oil blockage may occur when the lubricating oil flows through the sleeve-type throttle valve. In this case, by controlling the first solenoid valve to open and the second solenoid valve to close, the high-temperature and high-pressure refrigerant gas discharged from the compressor outlet enters the sleeve-type throttle valve to heat the sleeve-type throttle valve, thereby increasing the temperature of the lubricating oil flowing through the sleeve-type throttle valve and reducing the viscosity of the lubricating oil. This prevents oil blockage in the air conditioning system and improves the reliability of the air conditioning system operation.

[0100] In some embodiments, such as Figure 7 As shown, the method also includes the following steps:

[0101] S201. After the air conditioning system switches from heating mode to defrost mode for a second preset time, the second suction pressure value of the compressor and the first operating power of the compressor are obtained.

[0102] In some embodiments, to prevent the outdoor coil from frosting due to excessively low temperature, which would prevent the air conditioning system from heating, the controller acquires a fourth temperature value of the outdoor coil when the air conditioning system is in heating mode. When the fourth temperature value of the outdoor coil is detected to be below a third temperature threshold, the controller switches the air conditioning system from heating mode to defrosting mode. The third temperature threshold is preset at the factory, for example, -8°C.

[0103] Understandably, when the fourth temperature value of the outdoor coil is detected to be below the third temperature threshold, it means that the temperature value of the outdoor coil is too low and there is a possibility of frost formation. Therefore, when the fourth temperature value of the outdoor coil is detected to be below the third temperature threshold, the air conditioning system is controlled to switch from heating mode to defrost mode in order to defrost the outdoor coil.

[0104] In some embodiments, in order to ensure the stability of the acquired data, after the air conditioning system has entered the defrost mode for a second preset period of time, the controller acquires the second suction pressure value of the compressor through the second pressure sensor, and at the same time acquires the first operating power of the compressor.

[0105] The second preset duration is set at the factory, for example, 1 minute. The compressor's first operating power is the operating power of the air conditioning system when it is in defrost mode.

[0106] S202. Under the condition that the second preset condition is met, control the first solenoid valve to close and control the second solenoid valve to open.

[0107] In some embodiments, the second preset condition includes a second suction pressure value of the compressor that is above a first pressure threshold and a first operating power of the compressor that is above a first preset operating power.

[0108] The first pressure threshold is preset at the factory, for example, the first pressure threshold is 0.1 MPa. The first preset operating power is preset at the factory, for example, the first preset operating power is 400 W.

[0109] Understandably, when the second preset condition is met, the refrigerant in the air conditioning system is already in circulation. At this time, the indoor heat exchanger is used as an evaporator and the outdoor heat exchanger is used as a condenser. The second solenoid valve is located in the second pipeline between the compressor and the four-way valve. It is used to control the connection and disconnection of the refrigerant flowing through the second pipeline. Based on this, the first solenoid valve is closed and the second solenoid valve is opened, so that the high-temperature and high-pressure refrigerant gas generated by the compressor is discharged to the outdoor heat exchanger to increase the temperature of the outdoor coil and improve the defrosting efficiency.

[0110] For example, assuming the second preset duration is 1 minute, the first pressure threshold is 0.1 MPa, and the first preset operating power is 400 W, after the air conditioning system has been running in defrost mode for 1 minute, if the compressor's suction pressure is detected to be 0.6 MPa and the compressor's first operating power is 500 W, then the air conditioning system meets the second preset condition in defrost mode. In this case, the first solenoid valve is controlled to close, and the second solenoid valve is controlled to open, thereby increasing the coil temperature and improving the defrost efficiency.

[0111] S203. If the second preset condition is not met, control the heating belt to start working.

[0112] Understandably, if the second preset condition is not met, the heating belt will start working to heat the sleeve-type throttle valve, thereby increasing the temperature of the lubricating oil flowing through the sleeve-type throttle valve and reducing the viscosity of the lubricating oil. This prevents oil blockage in the air conditioning system and improves the reliability of the air conditioning system.

[0113] In some embodiments, such as Figure 8 As shown, after step S202, the method further includes the following steps:

[0114] S301. After controlling the first solenoid valve to close and the second solenoid valve to open for a third preset time, obtain the third temperature value of the outdoor coil.

[0115] In some embodiments, in order to detect in real time whether the defrosting work of the outdoor coil is completed, after controlling the first solenoid valve to close and the second solenoid valve to open for a third preset time, the controller obtains the third temperature value of the outdoor coil.

[0116] The third preset duration is set at the factory when the air conditioning system leaves the factory. The third preset duration is longer than the second preset duration. For example, the third preset duration is 3 minutes.

[0117] S302. When the detected third temperature value of the outdoor coil is above the temperature difference between the second temperature threshold and the third preset temperature value, the first solenoid valve is opened and the second solenoid valve is closed.

[0118] The second temperature threshold is preset at the factory, for example, the second temperature threshold is 12℃. The third preset temperature value is preset at the factory, for example, the third preset temperature value is 3℃.

[0119] Understandably, when the detected outdoor coil temperature exceeds the temperature difference between the second temperature threshold and the third preset temperature value, it indicates that the air conditioning system has entered defrost mode. The outdoor coil temperature has already risen, and the defrosting process is about to end. At this time, the refrigerant temperature in the refrigerant circulation loop is low, resulting in a low lubricating oil temperature and high viscosity, potentially leading to oil blockage. Therefore, the controller opens the first solenoid valve and closes the second solenoid valve, allowing the high-temperature, high-pressure refrigerant gas generated by the compressor to be discharged towards the sleeve-type throttle valve. This heats the sleeve-type throttle valve, increasing the temperature and reducing the viscosity of the lubricating oil flowing through it. This prevents oil blockage during the defrosting process and improves the reliability of the air conditioning system.

[0120] For example, assuming the third preset duration is 3 minutes, the second temperature threshold is 12℃, and the third preset temperature value is 3℃, after the air conditioning system has been running in defrost mode for 3 minutes, if the outdoor coil temperature is detected to be 11℃, the first solenoid valve is controlled to close and the second solenoid valve is controlled to open, thereby preventing oil blockage in the air conditioning system when the defrosting work is about to end and improving the reliability of the air conditioning system operation.

[0121] In some embodiments, such as Figure 9 As shown, the method also includes the following steps:

[0122] S401. After the air conditioning system switches from defrost mode to heating mode for a fourth preset time, the third suction pressure value of the compressor and the second operating power of the compressor are obtained.

[0123] Understandably, when the air conditioning system is in defrost mode, it cannot heat, resulting in a poor user experience. To avoid this issue, where the air conditioning system remains in defrost mode for extended periods without heating, the controller continuously monitors the fifth temperature value of the outdoor coil while the system is in defrost mode. When the controller detects that the fifth temperature value of the outdoor coil is above the fourth temperature threshold, it switches the air conditioning system from defrost mode to heating mode, where the fourth temperature threshold is above the third temperature threshold.

[0124] The fourth temperature threshold is preset at the factory when the air conditioning system leaves the factory; for example, the fourth temperature threshold is 12°C.

[0125] In some embodiments, after a fourth preset time has elapsed since the control system switched from defrosting mode to heating mode, the controller obtains the third suction pressure value of the compressor and the second operating power of the compressor through the second pressure sensor.

[0126] The fourth preset duration is set at the factory, for example, 2 minutes. The second operating power of the compressor is the operating power of the air conditioning system when it is in heating mode.

[0127] S402. Under the condition that the third preset condition is met, control the first solenoid valve to close and control the second solenoid valve to open.

[0128] The third preset condition includes that the compressor's third suction pressure value is above the first pressure threshold, and the compressor's second operating power is above the second preset operating power.

[0129] It is understandable that if oil blockage occurs in the air conditioning system, it will affect the compressor's suction pressure and operating power. However, if the third preset condition is met, it means that there is no oil blockage in the air conditioning system. At this time, the first solenoid valve is closed and the second solenoid valve is opened to stop heating the sleeve-type throttle valve.

[0130] S403. If the third preset condition is not met, control the heating belt to start working.

[0131] Understandably, if the third preset condition is not met, it means that even after the high-temperature and high-pressure refrigerant gas discharged from the compressor heats the sleeve-type throttle valve, the air conditioning system still experiences oil blockage, indicating that the current oil blockage problem is severe. In this case, the control heating belt starts working to further heat the sleeve-type throttle valve in order to resolve the oil blockage problem in the air conditioning system and ensure the reliability of the air conditioning system.

[0132] The following example illustrates a control method for an air conditioning system provided in this application. Figure 10 The diagram shown is an overall flow chart of a control method for an air conditioning system provided in this application according to an exemplary embodiment.

[0133] like Figure 10 As shown, after the air conditioning system is turned on, the operating mode of the air conditioning system is first detected. If the air conditioning system is in heating mode, after the air conditioning system runs in heating mode for a first preset time, the first temperature value of the outdoor coil, the first temperature value of the outdoor environment, the discharge pressure value of the compressor, and the first suction pressure value of the compressor are obtained, and it is determined whether the first preset condition is met. If the first preset condition is met, the first solenoid valve is controlled to open and the second solenoid valve is controlled to close, that is, the sleeve-type throttle valve is opened for preheating. If the first preset condition is not met, the detection is repeated. The first preset condition includes the outdoor coil temperature value being below the temperature between the first temperature threshold and the first preset temperature value, the temperature difference between the first temperature value of the outdoor environment and the first temperature value of the outdoor coil being above the second preset temperature value, and the pressure ratio between the compressor discharge pressure value and the compressor first suction pressure value being below the preset pressure ratio.

[0134] If the air conditioning system is in defrost mode, after the system has been running in defrost mode for a second preset time, the system acquires the compressor's second suction pressure and first operating power, and determines whether the second preset condition is met. If the second preset condition is met, the system controls the first solenoid valve to close and the second solenoid valve to open, effectively closing the preheating of the sleeve-type throttle valve. If the second preset condition is not met, the heating element is activated. The second preset condition includes that the compressor's second suction pressure is above the first pressure threshold and the compressor's first operating power is above the first preset operating power.

[0135] Furthermore, after the preheating of the sleeve-type throttle valve is closed, that is, after controlling the first solenoid valve to close and the second solenoid valve to open, the third temperature value of the outdoor coil is obtained after running for a third preset time. If the third temperature value of the outdoor coil is above the temperature difference between the second temperature threshold and the third preset temperature value, the first solenoid valve is controlled to open and the second solenoid valve is controlled to close, that is, the preheating of the sleeve-type throttle valve is started. If the above conditions are not met, the test is repeated.

[0136] If the air conditioning system switches from defrosting mode to heating mode, that is Figure 10 In the reheating mode, after running for a fourth preset time, the compressor's third suction pressure value and second operating power are acquired, and it is determined whether the third preset condition is met. If the third preset condition is met, the first solenoid valve is closed, and the second solenoid valve is opened, which means the preheating of the sleeve-type throttle valve is closed. If the second preset condition is not met, the heating belt is activated. The third preset condition includes that the compressor's second suction pressure value is above the first pressure threshold, and the compressor's second operating power is above the second preset operating power.

[0137] in, Figure 10 t1 is the first preset duration, t2 is the second preset duration, t3 is the third preset duration, t4 is the fourth preset duration, and T... w T represents the outdoor coil temperature. out The outdoor ambient temperature is T, and ΔT1 is the temperature difference between the first outdoor ambient temperature and the first outdoor coil temperature. d The first temperature threshold, ΔT p1 The first preset temperature value, △T p2 The second preset temperature value, △T p3 The third preset temperature value, P H P represents the compressor's discharge pressure. L Δr is the compressor's suction pressure value, r is the pressure ratio between the compressor's discharge pressure value and the compressor's first suction pressure value. p The preset pressure ratio for the compressor is 0.1, and the first pressure threshold for the compressor is w. c The operating power of the compressor, w SS The first preset operating power of the compressor, w Sr This is the second preset operating power for the compressor.

[0138] As can be seen, the above mainly describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, the embodiments of this application provide corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the modules and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0139] This application embodiment can divide the controller into functional modules according to the above method example. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. Optionally, the module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0140] This application also provides a hardware structure diagram of a controller, such as... Figure 11 As shown, 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, memory 3002 and communication interface 3003 are connected via a bus 3004.

[0141] Processor 3001 may be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. Processor 3001 may also be any other device with processing capabilities, such as a circuit, device, or software module. Processor 3001 may also include multiple CPUs, and processor 3001 may be a single-core processor or a multi-core processor. Here, "processor" may refer to one or more devices, circuits, or processing cores used to process data (e.g., computer program instructions).

[0142] The memory 3002 can be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions. It can also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), a magnetic disk storage medium, or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer. This application embodiment does not impose any limitations on this. The memory 3002 can exist independently or be integrated with the processor 3001. The memory 3002 may contain computer program code. The processor 3001 executes the computer program code stored in the memory 3002 to implement the air conditioning system control method provided in this application embodiment.

[0143] The communication interface 3003 can be used to communicate with other devices or communication networks (such as Ethernet, radio access network (RAN), wireless local area network (WLAN), etc.). The communication interface 3003 can be a module, circuit, transceiver, or any device capable of enabling communication.

[0144] Bus 3004 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Bus 3004 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 11 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0145] This invention also provides a computer-readable storage medium, which includes computer-executable instructions. When the computer-executable instructions are executed on the computer, the computer performs a control method for an air conditioning system as provided in the above embodiments.

[0146] This invention also provides a computer program product that can be directly loaded into a memory and contains software code. After being loaded and executed by a computer, the computer program product can realize the control method of an air conditioning system provided in the above embodiments.

[0147] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this invention can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0148] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0149] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and other division methods may exist in actual implementation. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate; components shown as units may be one physical unit or multiple physical units, i.e., they may be located in one place or distributed in multiple different places. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0150] Furthermore, the functional units in the various embodiments of this invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0151] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An air conditioning system, characterized in that, include: The refrigerant circulation loop allows the refrigerant to circulate within the compressor, outdoor heat exchanger, indoor heat exchanger, and four-way valve. An outdoor heat exchanger and an indoor heat exchanger, one of which functions as a condenser and the other as an evaporator; 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. A four-way valve is used to control the refrigerant flow direction in the refrigerant circulation loop; A sleeve-type throttle valve includes a valve core tube and a sleeve. The valve core tube is disposed inside the sleeve. One end of the sleeve is connected to the exhaust port of the compressor, and the other end is connected to the outdoor heat exchanger. A first solenoid valve is provided in the first pipeline between the compressor and the sleeve-type throttle valve, and is used to control the connection and disconnection of the refrigerant flowing through the first pipeline; The second solenoid valve is located in the second pipeline between the compressor and the four-way valve, and is used to control the connection and disconnection of the refrigerant flowing through the second pipeline; The first temperature sensor is used to detect the temperature value of the outdoor environment; The second temperature sensor is used to detect the temperature value of the outdoor coil. A first pressure sensor is installed at the exhaust port of the compressor to detect the exhaust pressure value of the compressor. The second pressure sensor is located at the air intake of the compressor and is used to detect the air intake pressure value of the compressor. The controller is configured as follows: After the air conditioning system has been in heating mode for a first preset period of time, the first temperature value of the outdoor environment, the first temperature value of the outdoor coil, the discharge pressure value of the compressor, and the first suction pressure value of the compressor are obtained. Under the condition of meeting the first preset condition, the first solenoid valve is controlled to open and the second solenoid valve is controlled to close; the first preset condition includes the first temperature value of the outdoor coil being below the temperature value between the first temperature threshold and the first preset temperature value, the temperature difference between the first temperature value of the outdoor environment and the first temperature value of the outdoor coil being above the second preset temperature value, and the pressure ratio between the discharge pressure value of the compressor and the first suction pressure value of the compressor being below the preset pressure ratio.

2. The air conditioning system according to claim 1, characterized in that, The air conditioning system also includes: A heating band is installed on the sleeve of the sleeve-type throttle valve for heating the sleeve-type throttle valve; The controller is also configured to: After a second preset time has elapsed since the air conditioning system switched from heating mode to defrost mode, the second suction pressure value of the compressor and the first operating power of the compressor are obtained. Under the condition that the second preset condition is met, the first solenoid valve is controlled to close and the second solenoid valve is controlled to open; the second preset condition includes that the second suction pressure value of the compressor is above the first pressure threshold and the first operating power of the compressor is above the first preset operating power. If the second preset condition is not met, the heating belt is controlled to start working.

3. The air conditioning system according to claim 2, characterized in that, The controller, configured to control the first solenoid valve to close and the second solenoid valve to open, is further configured to: After controlling the first solenoid valve to close and the second solenoid valve to open for a third preset time, the third temperature value of the outdoor coil is obtained. If the detected third temperature value of the outdoor coil exceeds the temperature difference between the second temperature threshold and the third preset temperature value, the first solenoid valve is opened and the second solenoid valve is closed.

4. The air conditioning system according to claim 3, characterized in that, The controller is also configured to: After a fourth preset time has elapsed since the air conditioning system switched from the defrosting mode to the heating mode, the third suction pressure value of the compressor and the second operating power of the compressor are obtained. Under the condition of meeting the third preset condition, the first solenoid valve is controlled to close and the second solenoid valve is controlled to open. The third preset condition includes that the second suction pressure value of the compressor is above the first pressure threshold and the second operating power of the compressor is above the second preset operating power. If the third preset condition is not met, the heating belt is controlled to start working.

5. The air conditioning system according to claim 4, characterized in that, The controller is configured to, when controlling the air conditioning system to switch from the heating mode to the defrosting mode, specifically configured as follows: When the air conditioning system is in heating mode, obtain the fourth temperature value of the outdoor coil; When the fourth temperature value of the coil is detected to be below the third temperature threshold, the air conditioning system is controlled to switch from the heating mode to the defrosting mode. The controller is configured to, when controlling the air conditioning system to switch from the defrosting mode to the heating mode, specifically configured as follows: When the air conditioning system is in defrost mode, the fifth temperature value of the outdoor coil is obtained; When the fifth temperature value of the coil is detected to be above the fourth temperature threshold, the air conditioning system is controlled to switch from the defrosting mode to the heating mode, wherein the fourth temperature threshold is above the third temperature threshold.

6. A control method for an air conditioning system, characterized in that, Applied to the air conditioning system according to any one of claims 1-5, the method comprises: After the air conditioning system has been in heating mode for a first preset time, the first outdoor ambient temperature value, the first outdoor coil temperature value, the compressor discharge pressure value, and the compressor suction pressure value are obtained. Under the condition that the first preset condition is met, the first solenoid valve is opened and the second solenoid valve is closed. The first preset condition includes the first temperature value of the outdoor coil being below the temperature value between the first temperature threshold and the first preset temperature value, the temperature difference between the first temperature value of the outdoor environment and the first temperature value of the outdoor coil being above the second preset temperature value, and the pressure ratio between the discharge pressure value of the compressor and the first suction pressure value of the compressor being below the preset pressure ratio.

7. The method according to claim 6, characterized in that, The method further includes: After a second preset time has elapsed since the air conditioning system switched from heating mode to defrost mode, the second suction pressure value of the compressor and the first operating power of the compressor are obtained. Under the condition that the second preset condition is met, the first solenoid valve is controlled to close and the second solenoid valve is controlled to open; the second preset condition includes that the second suction pressure value of the compressor is above the first pressure threshold and the first operating power of the compressor is above the first preset operating power. If the second preset condition is not met, the heating belt will start working.

8. The method according to claim 7, characterized in that, After controlling the first solenoid valve to close and the second solenoid valve to open, the method further includes: After controlling the first solenoid valve to close and the second solenoid valve to open for a third preset time, the third temperature value of the outdoor coil is obtained. If the detected third temperature value of the outdoor coil exceeds the temperature difference between the second temperature threshold and the third preset temperature value, the first solenoid valve is opened and the second solenoid valve is closed.

9. The method according to claim 8, characterized in that, The method further includes: After a fourth preset time has elapsed since the air conditioning system switched from the defrosting mode to the heating mode, the third suction pressure value of the compressor and the second operating power of the compressor are obtained. Under the condition that the third preset condition is met, the first solenoid valve is controlled to close and the second solenoid valve is controlled to open. The third preset condition includes that the third suction pressure value of the compressor is above the first pressure threshold and the second operating power of the compressor is above the second preset operating power. If the third preset condition is not met, the heating belt is controlled to start working.

10. The method according to claim 9, characterized in that, The control of the air conditioning system to switch from the heating mode to the defrosting mode includes: When the air conditioning system is in heating mode, obtain the fourth temperature value of the outdoor coil; When the fourth temperature value of the coil is detected to be below the third temperature threshold, the air conditioning system is controlled to switch from the heating mode to the defrosting mode. The control of the air conditioning system to switch from the defrosting mode to the heating mode includes: When the air conditioning system is in defrost mode, the fifth temperature value of the outdoor coil is obtained; When the fifth temperature value of the outdoor coil is detected to be above the fourth temperature threshold, the air conditioning system is controlled to switch from the defrosting mode to the heating mode, wherein the fourth temperature threshold is above the third temperature threshold.

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