Air conditioning system and control method thereof

Abstract

The embodiment of the application discloses an air conditioning system and a control method thereof, relates to the technical field of air conditioners, and is used for dynamically changing the heat exchange capacity of an indoor heat exchanger, thereby improving the energy efficiency ratio during air conditioner operation. The air conditioning system comprises an outdoor unit, an indoor unit comprising an indoor heat exchanger, an expansion valve used for adjusting the refrigerant flow through the indoor unit, and a controller configured to: acquire the heat exchange load of the indoor unit; determine the first opening degree of the expansion valve according to the heat exchange load of the indoor unit and a preset corresponding relationship, wherein the preset corresponding relationship is used for indicating the corresponding relationship between at least one heat exchange load and at least one opening degree of the expansion valve; determine the target opening degree used for adjusting the expansion valve according to the first opening degree and a preset opening degree of the expansion valve; and the preset opening degree is the opening degree of the expansion valve under the maximum heat exchange capacity of the indoor heat exchanger.

Description

TECHNICAL FIELD

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

[0002] For a long time, the design of air conditioning products focuses on the stability of the unit and the satisfaction of the use demand of users, and the energy saving target is not paid enough attention to. Generally, the energy efficiency is higher when the unit is running at full load, and the energy efficiency is lower when the unit is running at partial load.

[0003] At present, when installing the air conditioner, the selection is usually based on the maximum load of the indoor, so that the selection of the indoor unit of the air conditioner is large, which causes the output of the cooling capacity or the heating capacity of the indoor unit to be too large most of the time. When the output of the cooling capacity or the heating capacity of the indoor unit can quickly meet the current demand, the compressor will appear the phenomenon of frequent start and stop, which not only causes the indoor temperature to fluctuate greatly, increases the discomfort of the people in the room, but also causes the energy efficiency of the air conditioner to be low when the air conditioner is running.

[0004] Therefore, how to improve the energy efficiency ratio of the air conditioner when the air conditioner is running has become a problem to be solved at present. SUMMARY

[0005] The present application provides an air conditioning system and a control method thereof, which are used for dynamically changing the heat exchange capacity of an indoor heat exchanger, so as to improve the energy efficiency ratio of the air conditioner when the air conditioner is running.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions.

[0007] In a first aspect, an air conditioning system is provided, comprising: an outdoor unit; an indoor unit comprising an indoor heat exchanger; an expansion valve configured to adjust the flow of refrigerant through the indoor unit; and a controller configured to: obtain a heat exchange load of the indoor unit; determine a first opening degree of the expansion valve according to the heat exchange load of the indoor unit and a preset correspondence relationship, wherein the preset correspondence relationship is used to indicate the correspondence relationship between at least one heat exchange load and at least one opening degree of the expansion valve; determine a target opening degree of the expansion valve for adjusting the expansion valve according to the first opening degree and a preset opening degree of the expansion valve; and the preset opening degree is the opening degree of the expansion valve at the maximum heat exchange capacity of the indoor heat exchanger.

[0008] The technical scheme provided by the embodiments of the present application at least brings the following beneficial effects: the scheme can detect the current heat exchange load in real time, and based on the corresponding relationship between the heat exchange load of the indoor unit and the expansion valve, the opening degree of the expansion valve is adjusted, so as to adjust the refrigerant flow passing through the indoor unit heat exchanger, so that the heat exchange capacity of the indoor heat exchanger dynamically follows the heat exchange load of the current indoor unit, so as to avoid the overheat risk of the air conditioning system. At the same time, the heat exchange capacity of the indoor unit can also be controlled near the heat exchange load, ensuring that it is below the maximum heat exchange capacity of the indoor unit. In this way, not only the energy efficiency ratio of the air conditioning operation is improved, but also the indoor temperature is kept within the comfortable range, improving the user's use experience.

[0009] In some embodiments, the controller is further configured to: if the first opening degree is less than or equal to a preset opening degree, determine the first opening degree as a target opening degree for adjusting the expansion valve; and if the first opening degree is greater than the preset opening degree, determine the preset opening degree as the target opening degree for adjusting the expansion valve.

[0010] In some embodiments, the air conditioning system further comprises: a temperature sensor configured to detect the refrigerant temperature at the outlet of the indoor heat exchanger; and the controller is further configured to: periodically obtain a plurality of refrigerant temperature values at the outlet of the indoor heat exchanger through the temperature sensor at a preset time length when the indoor heat exchanger operates at the maximum heat exchange capacity; and determine the preset opening degree of the expansion valve according to the opening degree of the expansion valve corresponding to each refrigerant temperature value in the plurality of refrigerant temperature values.

[0011] In some embodiments, the air conditioning system further comprises: a compressor; a gas-liquid separator; and a bypass circuit connected at one end to the exhaust pipeline of the compressor and at the other end to the gas return pipeline of the compressor; or the bypass circuit is connected at one end to the exhaust pipeline of the compressor and at the other end to the gas inlet pipeline of the gas-liquid separator; and the controller is further configured to: when the target opening degree is less than an expansion valve opening degree threshold, turn on the bypass circuit.

[0012] In some embodiments, the controller is further configured to: obtain the suction superheat degree of the compressor; and when the suction superheat degree of the compressor is less than or equal to a first superheat degree threshold, turn off the bypass circuit.

[0013] In some embodiments, the controller is further configured to: obtain the discharge superheat degree of the compressor; and when the discharge superheat degree of the compressor is less than or equal to a second superheat degree threshold, turn off the bypass circuit.

[0014] In a second aspect, an embodiment of the present application provides a control method of an air conditioning system, the method comprising: obtaining a heat exchange load of an indoor unit; determining a first opening degree of an expansion valve according to the heat exchange load of the indoor unit and a preset corresponding relationship, wherein the preset corresponding relationship is used to indicate a corresponding relationship between at least one heat exchange load and at least one opening degree of the expansion valve; determining a target opening degree of the expansion valve for adjusting the expansion valve according to the first opening degree and a preset opening degree of the expansion valve; and the preset opening degree is an opening degree of the expansion valve at a maximum heat exchange capacity of an indoor heat exchanger.

[0015] 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, and the computer program codes comprise computer instructions, and when the one or more processors execute the computer instructions, the controller performs any of the control methods of the air conditioning system provided in the second aspect.

[0016] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium comprises computer instructions, and when the computer instructions run on a computer, the computer instructions cause the computer to perform the method provided in the second aspect and possible implementation manners.

[0017] In a fifth aspect, an embodiment of the present application provides a computer program product, and the computer program product can be directly loaded into a memory and contains software codes, and the computer program product can realize the method provided in the second aspect and possible implementation manners when the computer program product is loaded and executed by a computer.

[0018] 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.

[0019] 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, and will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0020] 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.

[0021] Figure 1 FIG. 1 is a schematic diagram of an air conditioning system provided by the present application;

[0022] Figure 2 FIG. 2 is a schematic diagram of internal elements of an air conditioning system provided by an embodiment of the present application;

[0023] Figure 3 A hardware configuration block diagram of an air conditioning system provided for an embodiment of the present application;

[0024] Figure 4 A control method flow chart of an air conditioning system provided for an embodiment of the present application;

[0025] Figure 5 A control method flow chart of determining a preset opening degree of an expansion valve provided for an embodiment of the present application;

[0026] Figure 6 A setting mode schematic diagram of a bypass circuit provided for an embodiment of the present application;

[0027] Figure 7 Another setting mode schematic diagram of a bypass circuit provided for an embodiment of the present application;

[0028] Figure 8 A control method flow chart of a bypass circuit provided for an embodiment of the present application;

[0029] Figure 9 Another control method flow chart of a bypass circuit provided for an embodiment of the present application;

[0030] Figure 10 A hardware structure schematic diagram of a controller provided for an embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described 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 other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0032] It should be noted that all directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directionality indications also change accordingly.

[0033] The terms "first", "second", etc. are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0034] In the description of the present application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected. For those skilled in the art, the specific meaning of the above terms in the present application can be understood in specific circumstances. In addition, when describing the pipeline, "connected" and "connected" in the present application have the meaning of conducting. The specific meaning needs to be understood in combination with the context.

[0035] In the embodiments of the present application, the words such as "exemplary" or "for example" are used to represent an example, illustration or description. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the words such as "exemplary" or "for example" are intended to present the relevant concept in a specific manner.

[0036] In order to facilitate understanding, first, some terms or basic concepts of the technology involved in the embodiments of the present application are simply introduced and described.

[0037] Cooling load: the heat that must be taken away from the room by the air conditioning system to maintain the required indoor temperature and thermal environment of the building is called the cooling load of the air conditioning room, or the amount of cold supplied to the room at a certain moment.

[0038] Heat load: the sum of various amounts of heat supplied to the air handling unit. The heat supplied to the air handling unit mainly includes the preheating amount of fresh air supplied to the fresh air pre-coil, the secondary heating amount supplied to the heating coil, and the heat supplied to the humidifier.

[0039] Proportion integration differentiation (PID): the most widely used controller at present, which controls the controlled object by linear combination of the proportion and integral of the control deviation formed by the given value and the actual output value. In the present application, PID control is used to calculate the heat exchange load of the indoor unit.

[0040] As described above, the existing air conditioning system indoor unit cannot dynamically change the indoor heat exchanger capacity, resulting in relatively low efficiency of air conditioning operation and low user comfort.

[0041] Based on this, this application provides an air conditioning system, including: an outdoor unit; an indoor unit including an indoor heat exchanger; an expansion valve for regulating the refrigerant flow through the indoor unit; and a controller configured to: acquire the heat exchange load of the indoor unit; determine a first opening degree of the expansion valve based on the heat exchange load of the indoor unit and a preset correspondence, wherein the preset correspondence indicates the correspondence between at least one heat exchange load and at least one opening degree of the expansion valve; and determine a target opening degree for adjusting the expansion valve based on the first opening degree and the preset opening degree of the expansion valve; the preset opening degree is the opening degree of the expansion valve under the maximum heat exchange capacity of the indoor heat exchanger. In this way, the heat exchange capacity of the indoor heat exchanger can dynamically follow the heat exchange load, improving the energy efficiency ratio of the air conditioning operation.

[0042] The embodiments provided in this application will now be described in detail with reference to the accompanying drawings.

[0043] Figure 1 This is a schematic diagram of the composition of an air conditioning system provided in an embodiment of this application. Figure 2 This is a schematic diagram of the internal components of an air conditioning system provided in an embodiment of this application. The following is in conjunction with... Figure 1 and Figure 2 This application describes the air conditioning system provided in the embodiments.

[0044] like Figure 1 As shown, the air conditioning system 100 includes an outdoor unit 10, an indoor unit 11, and a controller 1000. Figure 1 (Not shown in the image). The indoor unit 11 includes at least one indoor unit, and each indoor unit is connected to the outdoor unit via refrigerant connection pipes.

[0045] Figure 1 The previous example only involved one outdoor unit connected to two indoor units. This application provides a multi-split air conditioning system where one outdoor unit connects to multiple indoor units. Figure 1 The composition of the multi-split air conditioning system does not constitute a limitation on this multi-split air conditioning system.

[0046] Outdoor unit 10 is typically installed outdoors for heat exchange within the indoor environment. Additionally, in Figure 2 In the illustration, outdoor unit 10 is shown as a dashed line because it is located outdoors on the opposite side of indoor unit 11, separated by a wall.

[0047] like Figure 1 As shown, the outdoor unit 10 includes: a compressor 101, an oil separator 102, a reversing valve 103, an outdoor fan 104, an outdoor heat exchanger 105, a liquid receiver 106, a gas-liquid separator 107, a subcooler 108, a subcooling / injection expansion valve 109, a bypass solenoid valve 110, an oil separator solenoid valve 111, and an external expansion valve 112.

[0048] In some embodiments, the compressor 101 is a driven fluid machine that raises low-pressure gas to high-pressure gas. In the multi-split air conditioning system 100 operating in the cooling mode, the compressor 101 is used to compress the refrigerant gas in a high-temperature and high-pressure state and discharge the compressed refrigerant gas. The refrigerant discharged by the compressor 101 flows into the condenser. The condenser condenses the compressed refrigerant into a liquid state, and heat is released to the surrounding environment through the condensation process.

[0049] In some embodiments, the oil separator 102 is used to separate the lubricating oil in the high-pressure steam discharged by the refrigeration compressor to ensure that the air conditioning system operates safely and efficiently.

[0050] In some embodiments, the reversing valve 103 is used to change the flow direction of the refrigerant gas.

[0051] In some embodiments, the outdoor fan 104 is used to dissipate the heat released by the outdoor heat exchanger 105 to the air.

[0052] In some embodiments, the subcooler 108 is used to reduce the temperature of the refrigerant liquid, reduce the gas generated by the sudden reduction in pressure of a portion of the liquid refrigerant generated after throttling, and improve the refrigeration efficiency.

[0053] In some embodiments, the subcooling / liquid injection expansion valve 109 is used to cool the compressor 101.

[0054] In some embodiments, the subcooling / liquid injection expansion valve 109 controls the load of the evaporator to avoid frequent start-stop of the compressor.

[0055] In some embodiments, the oil separation solenoid valve 111 is used for automatic control of the on-off of liquid and gas media in the pipeline.

[0056] The indoor unit 11, for example, an indoor hanging machine, is usually installed on a wall surface such as an indoor wall surface. For another example, an indoor cabinet machine (not shown) is also a type of indoor machine. The air conditioning system can include an outdoor unit and at least one indoor cabinet machine. Figure 3

[0057] The indoor unit 11 includes an indoor heat exchanger group 113, an indoor fan group 114, and an indoor expansion valve group 115.

[0058] ​In the embodiments shown in the present application, the controller 1000 refers to a device that can generate operation control signals according to instruction operation codes and timing signals, and instruct the air conditioning system 100 to execute control instructions. For example, the controller 1000 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 controller 1000 can also be other devices with processing functions, such as circuits, devices, or software modules, and the embodiments of the present application do not make any limitation in this regard.

[0059] In addition, the controller 1000 can be used to control various components inside the air conditioning system 100, so that the various components operate to achieve various predetermined functions of the air conditioning system 100.

[0060] Figure 3 A hardware configuration block diagram of an air conditioning system 100 according to an exemplary embodiment of the present application is provided. As shown in the figure, the air conditioning system 100 can further include the following two items: a memory 1002 and a communication interface 1003. Figure 3

[0061] The memory 1002 can be used to store software programs and data. The controller 1000 executes various functions and data processing of the air conditioning system 100 by running the software programs or data stored in the memory 1002. The memory 1002 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device. The memory 1002 stores an operating system that enables the air conditioning system 100 to operate. In the present application, the memory 1002 can store an operating system and various application programs, and can also store codes for executing the control method of the air conditioning system 100 provided by the embodiments of the present application.

[0062] ​In some embodiments, the communication interface 1003 is configured to establish a communication connection with other network entities, such as a terminal device. The communication interface 1003 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, to send the received information to the controller 1000 for processing, and to send the signals generated by the controller 1000. 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.

[0063] Those skilled in the art can understand that the hardware structure shown in the above Figure 4 The air conditioning system 100 can include more or fewer components than those shown in the figure, or combine certain components, or different component arrangements.

[0064] Figure 4 An air conditioning system control method flowchart provided by the embodiments of the present application is applied to the controller 1000 in the above air conditioning system 100, as shown in the figure, the method comprises the following steps. Heat exchange load

[0065] S101, the controller acquires the heat exchange load of the indoor unit.

[0066] The heat exchange load of the indoor unit includes the cooling load of the indoor unit in the cooling state or the heating load of the indoor unit in the heating state.

[0067] Optionally, the heat exchange load of the indoor unit can be indirectly acquired by adjusting the indoor temperature through a PID control algorithm, or can be estimated by modeling, which is not limited in the present application.

[0068] S102, the controller determines the first opening degree of the expansion valve according to the heat exchange load of the indoor unit and a preset corresponding relationship.

[0069] The preset corresponding relationship is used to indicate the corresponding relationship between at least one heat exchange load and at least one opening degree of the expansion valve.

[0070] For example, the preset corresponding relationship can be implemented in the form of a corresponding relationship table. Table 1 shows a corresponding relationship table, as shown in Table 1, the preset corresponding relationship can include a plurality of heat exchange loads and first opening degrees. And the plurality of heat exchange loads and the first opening degrees have a one-to-one correspondence.

[0071] Table 1

[0072] ​ First opening degree Figure 5 A W ]] PLS A <!-- 5 -->]]> B W ]] PLS B ]] [C W ]]> PLS C ]]> ... ...

[0073] For example, when the heat exchange load of the indoor unit is A W , the first opening degree of the expansion valve is PLS A When the heat exchange load of the indoor unit is B W , the first opening degree of the expansion valve is PLS B When the heat exchange load of the indoor unit is C W , the first opening degree of the expansion valve is PLS C .

[0074] S103, the controller determines a target opening degree of the expansion valve according to the first opening degree and a preset opening degree of the expansion valve.

[0075] The preset opening degree is the opening degree of the expansion valve at the maximum heat exchange capacity of the indoor heat exchanger.

[0076] It should be noted that the maximum heat exchange capacity of the indoor heat exchanger refers to the operating capacity of the heat exchanger when the refrigerant flowing through the indoor heat exchanger is just all changed into gas after the liquid refrigerant absorbs the indoor heat. At this time, the corresponding opening degree of the expansion valve is the preset opening degree.

[0077] Figure 5 A control method flow chart for determining the preset opening degree of the expansion valve provided by the embodiment of the application is shown in FIG. 2, which includes the following steps: Refrigerant temperature value

[0078] S1031, the controller periodically acquires a plurality of refrigerant temperature values at the outlet of the indoor heat exchanger through the temperature sensor at a preset time length when the indoor heat exchanger operates at the maximum heat exchange capacity.

[0079] Optionally, the preset time length can be 30 seconds, 60 seconds, etc.

[0080] S1032, the controller determines the preset opening degree of the expansion valve according to the opening degree of the expansion valve corresponding to each refrigerant temperature value in the plurality of refrigerant temperature values.

[0081] Optionally, the controller can determine the preset opening degree of the expansion valve according to a preset correspondence between the refrigerant temperature value and the opening degree of the expansion valve.

[0082] The preset correspondence is used to indicate at least one refrigerant temperature value and at least one preset opening degree of the expansion valve.

[0083] For example, the preset correspondence can be implemented in the form of a correspondence table. Table 2 shows a correspondence table, as shown in Table 2, which includes a plurality of refrigerant temperature values and a plurality of preset opening degrees of the expansion valve, and there is a one-to-one correspondence between at least one refrigerant temperature value and at least one preset opening degree of the expansion valve.​

[0084] Table 2

[0085] Expansion valve preset opening degree Figure 6 X ℃ ]]> PLS X ]]> Y ℃ ]]> PLS Y ]]> Z ℃ ]]> PLS Z ]]> ... ...

[0086] For example, when the refrigerant temperature value is X ℃ , the preset opening degree of the expansion valve is PLS X When the refrigerant temperature value is Y ℃ , the preset opening degree of the expansion valve is PLS Y When the refrigerant temperature value is Z ℃ , the preset opening degree of the expansion valve is PLS Z .

[0087] Thus, for the plurality of refrigerant temperature values, the plurality of expansion valve opening degrees can be determined based on the preset correspondence between the refrigerant temperature values and the expansion valve opening degrees as shown in Table 2.

[0088] Further, the maximum opening degree of the plurality of expansion valve opening degrees is determined as the preset opening degree.

[0089] In some embodiments, after the preset opening degree is determined, the first opening degree and the preset opening degree can be compared, and a suitable opening degree is selected as the target opening degree from among the first opening degree and the preset opening degree.

[0090] Optionally, if the first opening degree is less than or equal to the preset opening degree, the first opening degree is determined as the target opening degree for adjusting the expansion valve. If the first opening degree is greater than the preset opening degree, the preset opening degree is determined as the target opening degree for adjusting the expansion valve.

[0091] It should be understood that after the target opening degree is determined, the controller can adjust the expansion valve opening degree to the determined target opening degree. Thus, the refrigerant flow rate through the indoor unit is adjusted, so as to achieve the effect of dynamically adjusting the heat exchange capacity of the indoor heat exchanger.

[0092] The technical scheme provided by the embodiments of the present application at least brings the following beneficial effects: according to the correspondence between the heat exchange load of the indoor unit and the expansion valve, the opening degree of the expansion valve is adjusted, so as to adjust the refrigerant flow rate through the indoor heat exchanger, so as to realize that the heat exchange capacity of the indoor heat exchanger dynamically follows the heat exchange load, thereby avoiding the overheat risk of the air conditioning system. At the same time, the heat exchange capacity of the indoor unit can be controlled near the heat exchange load, so as to ensure that the maximum heat exchange capacity of the indoor unit is below. Thus, not only the energy efficiency ratio of the air conditioning operation is improved, but also the indoor temperature is kept in the comfortable range, so as to improve the user experience.

[0093] In some embodiments, when the heat exchange load of the indoor unit decreases to below the maximum heat exchange capacity of the indoor unit's heat exchanger, the reduced refrigerant volume leads to increased superheat, which may cause compressor damage. To address this issue, this application embodiment employs a method of adding a bypass circuit to the outdoor unit to compensate the compressor to a suitable temperature, ensuring stable and safe operation of the compressor.

[0094] Figure 6 This is a schematic diagram illustrating a bypass circuit configuration provided in an embodiment of this application, as shown below. Figure 7 As shown, one end of the bypass circuit is connected to the compressor's exhaust pipe, and the other end is connected to the compressor's return pipe.

[0095] Figure 7 A schematic diagram illustrating another bypass circuit configuration provided in this application embodiment is shown below. Figure 8 As shown, one end of the bypass circuit is connected to the compressor's exhaust pipe, and the other end is connected to the gas-liquid separator's inlet pipe.

[0096] In some embodiments, when the target opening degree of the expansion valve is less than the opening threshold of the expansion valve, the bypass circuit described above is activated.

[0097] The expansion valve opening threshold is the minimum expansion valve opening preset within the air conditioning system.

[0098] For example, when the target opening degree of the expansion valve is less than the opening threshold, the indoor unit heat exchanger cannot achieve its maximum heat exchange capacity. The outlet temperature of the indoor unit heat exchanger is too high, causing the refrigerant temperature at the compressor suction port to be too high, resulting in an excessively high compressor operating temperature and potentially burning out the compressor. In this situation, opening the bypass circuit allows some liquid refrigerant to bypass from the high-pressure side to the compressor suction port or the gas-liquid separator inlet, cooling the refrigerant and thus protecting the compressor.

[0099] Figure 8 A flowchart of a bypass loop control method provided in an embodiment of this application is shown below. Figure 9 As shown, the method includes the following steps:

[0100] S201, The controller obtains the suction superheat of the compressor.

[0101] Among them, the suction superheat refers to the difference between the saturation temperature corresponding to the refrigerant pressure at a certain point at the outlet of the outdoor unit heat exchanger and the actual temperature of the refrigerant.

[0102] S202. When the compressor's suction superheat is less than or equal to the first superheat threshold, the controller closes the bypass circuit.

[0103] Optionally, the range of suction superheat is between the minimum suction superheat required for safe operation of the compressor and the maximum suction superheat required for safe operation of the compressor.

[0104] In a specific implementation, the suction superheat is denoted by Δ SSH , the minimum suction superheat is denoted by Δ SSH_min , and the maximum suction superheat is denoted by Δ SSH_max .

[0105] That is, Δ SSH_max ≥ Δ SSH ≥ Δ SSH_min .

[0106] The first superheat threshold is used to indicate the minimum suction superheat required in the safe operation state of the compressor.

[0107] For example, when Δ SSH ≤ Δ SSH_min , the controller controls the bypass circuit to be closed.

[0108] Figure 9 Another control method flow chart of the bypass circuit provided by the embodiment of the present application is shown in FIG. 3B, and the method includes the following steps: Figure 10

[0109] S301, the controller acquires the discharge superheat of the compressor.

[0110] The discharge superheat refers to the temperature difference between the temperature of the discharge pipe or the inlet of the heat exchanger of the compressor and the saturation temperature corresponding to the actual heat exchange pressure.

[0111] S302, when the discharge superheat of the compressor is less than or equal to the second superheat threshold, the controller controls the bypass circuit to be closed.

[0112] Optionally, the range of the discharge superheat is between the minimum discharge superheat required in the safe operation state of the compressor and the maximum discharge superheat required in the safe operation state of the compressor.

[0113] In a specific implementation, the suction superheat is denoted by Δ DSH , the minimum suction superheat is denoted by Δ DSH_min , and the maximum suction superheat is denoted by Δ DSH_max .

[0114] That is, Δ DSH_max ≥ Δ DSH ≥ Δ DSH_min .

[0115] The second superheat threshold is used to indicate the minimum discharge superheat required in the safe operation state of the compressor.

[0116] For example, when Δ DSH ≤ Δ DSH_min , the controller controls the bypass circuit to be closed.​

[0117] The technical scheme provided by the embodiments of the present application brings at least the following beneficial effects: by adding a bypass circuit to the outdoor unit, the refrigerant is bypassed to the circuit of the compressor inlet or the gas-liquid separator inlet, so as to control the suction superheat and the discharge superheat of the compressor, which not only ensures the reliable and stable operation of the air conditioning system, but also enables the air conditioning system to run at the highest possible evaporation pressure in the cooling mode and at the lowest possible condensation pressure in the heating mode, thereby achieving the effect of energy saving and emission reduction.

[0118] The embodiments of the present application also provide a hardware structure diagram of a controller, as shown in Figure 10 The controller 1000 includes a processor 1001. Optionally, the controller 1000 also includes a memory 1002 and a communication interface 1003 connected with the processor 1001. The processor 1001, the memory 1002 and the communication interface 1003 are connected through a bus 1004.

[0119] The processor 1001 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 1001 can also be any other device with processing function, such as a circuit, a device or a software module. The processor 1001 can also include multiple CPUs, and the processor 1001 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 (such as computer program instructions).

[0120] The memory 1002 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 instructions or data that can be accessed by a computer, and the embodiments of the present application do not make any limitation on this. The memory 1002 can exist independently or be integrated with the processor 1001. The memory 1002 can contain computer program codes. The processor 1001 is configured to execute the computer program codes stored in the memory 1002, so as to implement the control method provided by the embodiments of the present application.

[0121] The communication interface 1003 can be configured to communicate with other devices or communication networks (such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.). The communication interface 1003 can be a module, a circuit, a transceiver or any device capable of realizing communication.

[0122] The bus 1004 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 1004 can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, ​ Only one thick line is used in the figure, but it does not mean that there is only one bus or only one type of bus.

[0123] 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 the computer, the computer is caused to execute the method provided by the above embodiments.

[0124] The embodiment of the present application further provides a computer program product, which can be directly loaded into the memory and contains software codes, and the computer program product can realize the method provided by the above embodiment after being loaded and executed by a computer.

[0125] 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.

[0126] 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.

[0127] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented by other ways. For example, the apparatus embodiments described above are only exemplary, for example, the division of the modules or units is only a logical function division, and actual implementation can have another division way. For example, a plurality of units or components can be combined or integrated into another device, or some features can be ignored 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, and 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 a 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 realize the purpose of the embodiment scheme.

[0128] 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 number 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 embodiments of the present application method. 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.

[0129] 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: Outdoor unit; Indoor unit, including indoor heat exchanger; An expansion valve is used to regulate the refrigerant flow through the indoor unit; A temperature sensor is used to detect the refrigerant temperature at the outlet of the indoor heat exchanger; compressor; Gas-liquid separator; A bypass circuit, one end of which is connected to the compressor's exhaust pipe, and the other end of which is connected to the compressor's return pipe; or, One end of the bypass circuit is connected to the exhaust pipe of the compressor, and the other end is connected to the inlet pipe of the gas-liquid separator. The controller is configured as follows: Obtain the heat exchange load of the indoor unit; The first opening degree of the expansion valve is determined based on the heat exchange load of the indoor unit and a preset correspondence, wherein the preset correspondence is used to indicate the correspondence between at least one heat exchange load and at least one opening degree of the expansion valve; When the indoor heat exchanger is running at its maximum heat exchange capacity, multiple refrigerant temperature values ​​at the outlet of the indoor heat exchanger are periodically obtained through the temperature sensor at preset intervals. The preset opening degree of the expansion valve is determined based on the opening degree of the expansion valve corresponding to each of the plurality of refrigerant temperature values. Based on the first opening degree and the preset opening degree of the expansion valve, a target opening degree for adjusting the expansion valve is determined.

2. The air conditioning system according to claim 1, characterized in that, The controller is also configured to: If the first opening degree is less than or equal to the preset opening degree, the first opening degree is determined as the target opening degree for adjusting the expansion valve; If the first opening degree is greater than the preset opening degree, the preset opening degree is determined as the target opening degree for adjusting the expansion valve.

3. The air conditioning system according to any one of claims 1 to 2, characterized in that, The controller is also configured to: When the target opening degree is less than the expansion valve opening degree threshold, the bypass circuit is opened.

4. The air conditioning system according to claim 3, characterized in that, The controller is also configured to: Obtain the suction superheat of the compressor; When the suction superheat of the compressor is less than or equal to the first superheat threshold, the bypass circuit is closed.

5. The air conditioning system according to claim 3, characterized in that, The controller is also configured to: Obtain the exhaust superheat of the compressor; When the exhaust superheat of the compressor is less than or equal to the second superheat threshold, the bypass circuit is closed.

6. A control method for an air conditioning system, characterized in that, The method, applied to the air conditioning system according to any one of claims 1-5, comprises: Obtain the heat exchange load of the indoor unit; The first opening degree of the expansion valve is determined based on the heat exchange load of the indoor unit and a preset correspondence, wherein the preset correspondence is used to indicate the correspondence between at least one heat exchange load and at least one opening degree of the expansion valve; When the indoor heat exchanger is running at its maximum heat exchange capacity, multiple refrigerant temperature values ​​at the outlet of the indoor heat exchanger are periodically acquired at a preset time interval. The preset opening degree of the expansion valve is determined based on the opening degree of the expansion valve corresponding to each of the plurality of refrigerant temperature values. Based on the first opening degree and the preset opening degree of the expansion valve, a target opening degree for adjusting the expansion valve is determined.

7. The control method for an air conditioning system according to claim 6, characterized in that, The step of determining the target opening degree for adjusting the expansion valve based on the first opening degree and the preset opening degree of the expansion valve includes: If the first opening degree is less than or equal to the preset opening degree, the first opening degree is determined as the target opening degree for adjusting the expansion valve; If the first opening degree is greater than the preset opening degree, the preset opening degree is determined as the target opening degree for adjusting the expansion valve.

8. The control method for an air conditioning system according to claim 6, characterized in that, The method further includes: Obtain the compressor's suction superheat; When the suction superheat of the compressor is less than or equal to the first superheat threshold, the bypass circuit is closed.

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