A multi-split air conditioning system and a control method thereof

Abstract

The application provides a multi-connected air conditioning system and a control method thereof, and relates to the technical field of air conditioners. The control method of the multi-connected air conditioning system comprises the following steps: controlling a first indoor unit to operate and other indoor units in an indoor unit group to stop operating, except for the first indoor unit; controlling the opening degree of a first indoor expansion valve to be adjusted to each first test opening degree in a plurality of first test opening degrees in sequence, and obtaining the refrigerant mass flow of a refrigerant circulating main loop under each first test opening degree in sequence, the first indoor expansion valve being an indoor expansion valve in the first indoor unit; determining the equivalent passage area of the first indoor expansion valve under each first test opening degree according to the refrigerant mass flow of the refrigerant circulating main loop under each first test opening degree; and performing function fitting on the equivalent passage area of the first indoor expansion valve under each first test opening degree to obtain an opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve.

Description

TECHNICAL FIELD

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

[0002] The multi-split air conditioning system is a multi-terminal and variable refrigerant mass flow refrigeration / heat system, which has the characteristics of flexible control, energy saving and low operation cost, and is increasingly widely used in small and medium-sized buildings. In the prior art, the multi-split air conditioning system is metered according to the individual refrigeration / heat of each terminal device, which is a relatively fair multi-split air conditioning billing method in the prior art. The related technology provides a billing method, which needs to determine the equivalent passage area of the indoor expansion valve of each indoor unit according to the opening-equal passage area function of the indoor expansion valve of each indoor unit, and calculate the refrigeration / heat of each indoor unit in the operation time period, so as to realize the sub-metering of the multi-split air conditioning system.

[0003] At present, the opening-equal passage area function of the indoor expansion valve used in the multi-split air conditioning system is obtained by simulation under ideal working conditions, and is configured in the memory of the multi-split air conditioning system by the manufacturer when the multi-split air conditioning system is shipped. However, the indoor heat exchanger and the expansion valve in each indoor unit of the multi-split air conditioning system inevitably have different degrees of dirt and blockage in actual use, which causes the equivalent passage area of the indoor expansion valve calculated by the pre-configured opening-equal passage area function of the indoor expansion valve to be unmatched with the actual equivalent passage area, and further affects the calculation accuracy of the refrigeration / heat of each indoor unit, which is not conducive to realizing the fair billing of the multi-split air conditioning system. SUMMARY

[0004] The embodiments of the present application provide a multi-split air conditioning system and a control method thereof, which are used to solve the problem that the pre-configured opening-equal passage area function of the indoor expansion valve of the multi-split air conditioning system is not accurate enough.

[0005] To achieve the above object, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, a multi-split air conditioning system is provided, which comprises:

[0007] A refrigerant circulation main loop comprising a compressor, a four-way valve, an outdoor heat exchanger and an indoor unit group connected in series, the indoor unit group comprising a plurality of indoor units arranged side by side, each indoor unit comprising an indoor expansion valve and an indoor heat exchanger;

[0008] A controller configured to:

[0009] Control the first indoor unit to operate and the other indoor units in the indoor unit group except the first indoor unit to stop operating;

[0010] The opening degree of the first indoor expansion valve is adjusted to each of a plurality of first test opening degrees in turn, and the refrigerant mass flow of the refrigerant circulation main loop is obtained at each of the first test opening degrees in turn, the first indoor expansion valve being an indoor expansion valve in the first indoor unit;

[0011] According to the refrigerant mass flow of the refrigerant circulation main loop at each of the first test opening degrees, the equivalent passage area of the first indoor expansion valve at each of the first test opening degrees is determined.

[0012] The equivalent passage area of the first indoor expansion valve at each of the first test opening degrees is subjected to function fitting, and an opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve is obtained.

[0013] The technical scheme provided by the embodiments of the present application at least brings the following beneficial effects: by controlling the first indoor unit to run and the other indoor units in the indoor unit group except the first indoor unit to stop running, the refrigerant mass flow of the refrigerant circulation main loop is equivalent to the refrigerant mass flow of the indoor expansion valve of the first indoor unit. In this way, by continuously changing the indoor expansion valve in the first indoor unit, the refrigerant mass flow of the indoor expansion valve of the first indoor unit at different test opening degrees can be obtained. Finally, by the refrigerant mass flow of the indoor expansion valve of the first indoor unit at a plurality of test opening degrees, an opening degree-equivalent passage area fitting function conforming to the actual situation can be fitted.

[0014] In some embodiments, the multi-split air conditioning system further comprises an outdoor unit fan, and the controller of the multi-split air conditioning system is further configured to obtain the refrigerant mass flow of the refrigerant circulation main loop at each of the first test opening degrees in turn, and specifically performs the following steps: for each of the first test opening degrees, after the first indoor expansion valve is adjusted to the first test opening degree, the rotating speed of the outdoor unit fan and / or the frequency of the compressor are adjusted so that the suction superheat degree of the compressor is greater than or equal to a preset value; after the suction superheat degree of the compressor is greater than or equal to the preset value, the refrigerant mass flow of the refrigerant circulation main loop at the first test opening degree is obtained.

[0015] It can be understood that the suction superheat of the compressor refers to the difference between the suction temperature of the compressor and the evaporation temperature of the refrigerant. The suction superheat of the compressor exists to ensure that no liquid refrigerant enters the compressor to cause damage to the compressor. In addition, when the suction superheat of the compressor is too small, the refrigerant at the suction port of the compressor can be in a two-phase state. Since the enthalpy value of the refrigerant in the two-phase state cannot be accurately calculated according to the energy balance method, in order to avoid the influence of the two-phase state of the refrigerant at the suction port of the compressor, the suction superheat of the compressor needs to be greater than or equal to a preset value to ensure the calculation accuracy of the energy balance method and the calibration accuracy of the sub-metering. To this end, the rotational speed of the outdoor fan and / or the frequency of the compressor are adjusted to change the suction superheat of the compressor.

[0016] In some embodiments, the controller of the multi-split air conditioning system is further configured to obtain the refrigerant mass flow rate of the refrigerant circulation main loop at the first test opening degree after the suction superheat of the compressor is greater than or equal to the preset value, and specifically performs the following steps: obtaining the suction temperature, suction pressure, discharge temperature, discharge pressure, shell temperature, ambient temperature, shell surface area, and power of the compressor after the suction superheat of the compressor is greater than or equal to the preset value; determining the suction refrigerant enthalpy of the compressor based on the suction temperature and the suction pressure; determining the discharge refrigerant enthalpy of the compressor based on the discharge temperature and the discharge pressure; determining the heat leakage of the compressor based on the shell temperature, the ambient temperature, and the shell surface area; and determining the refrigerant mass flow rate of the refrigerant circulation main loop based on the heat leakage, the suction refrigerant enthalpy of the compressor, the discharge refrigerant enthalpy of the compressor, and the power.

[0017] It can be understood that the enthalpy of the refrigerant is related to the temperature and pressure. The heat leakage of the compressor is the loss during the operation of the compressor. The refrigerant mass flow rate of the refrigerant circulation main loop is determined based on the heat leakage, the suction refrigerant enthalpy of the compressor, the discharge refrigerant enthalpy of the compressor, and the power, which is a correction to the main flow rate of the compressor refrigerant in an ideal state.

[0018] In some embodiments, the controller of the multi-split air conditioning system is further configured to, after obtaining the opening-equivalent passage area fitting function corresponding to the first indoor expansion valve, control the second indoor unit to operate, and control other indoor units in the indoor unit group except the second indoor unit to stop operating; control the opening of the second indoor expansion valve to be adjusted to each of a plurality of second test openings in turn, and obtain the refrigerant mass flow of the refrigerant circulating main loop at each of the second test openings in turn, the second indoor expansion valve being an indoor expansion valve in the second indoor unit; determine the equivalent passage area of the second indoor expansion valve at each of the second test openings according to the refrigerant mass flow of the refrigerant circulating main loop at each of the second test openings; and perform function fitting on the equivalent passage area of the second indoor expansion valve at each of the second test openings to obtain an opening-equivalent passage area fitting function corresponding to the second indoor expansion valve.

[0019] It can be understood that, in the case of controlling only the second indoor unit to operate, the refrigerant discharged by the compressor can all flow through the second indoor unit, so that the flow rate of the refrigerant passing through the second indoor expansion valve can be measured according to the main flow of the compressor. The refrigerant mass flow of the refrigerant circulating main loop at a corresponding opening of the second indoor expansion valve is obtained by changing the opening of the second indoor expansion valve, and then the equivalent passage area of the second indoor expansion valve at the corresponding opening is determined, and further the opening-equivalent passage area fitting function corresponding to the second indoor expansion valve is obtained. In this way, the actual equivalent passage area corresponding to the opening of the second indoor expansion valve can be calculated through the opening-equivalent passage area fitting function corresponding to the second indoor expansion valve, and the calibration of the parameters of the second indoor expansion valve is completed.

[0020] In some embodiments, the controller of the multi-split air conditioning system is further configured to, after obtaining the opening-equivalent passage area fitting function corresponding to the first indoor expansion valve, control the first indoor unit and the second indoor unit to operate, and control other indoor units in the indoor unit group except the second indoor unit to stop operating; control the opening of the first indoor expansion valve to be adjusted to a preset opening, control the opening of the second indoor expansion valve to be adjusted to each of a plurality of second test openings in turn, and obtain the refrigerant mass flow of the refrigerant circulating main loop at each of the second test openings in turn, the second indoor expansion valve being an indoor expansion valve in the second indoor unit; determine the refrigerant mass flow of the first indoor expansion valve according to the opening-equivalent passage area fitting function corresponding to the first indoor expansion valve and the preset opening; for each of the second test openings, take the difference between the refrigerant mass flow of the refrigerant circulating main loop at the second test opening and the refrigerant command flow of the first indoor expansion valve as the refrigerant mass flow of the second indoor expansion valve at the second test opening; determine the equivalent passage area of the second indoor expansion valve at each of the second test openings according to the refrigerant mass flow of the second indoor expansion valve at each of the second test openings; and perform function fitting on the equivalent passage area of the second indoor expansion valve at each of the second test openings to obtain the opening-equivalent passage area fitting function corresponding to the second indoor expansion valve.

[0021] It can be understood that, after obtaining the opening-equivalent passage area fitting function corresponding to the first indoor expansion valve, the equivalent passage area of the first indoor expansion valve corresponding to the opening can be obtained according to the fitting function. At this time, the second indoor unit is controlled to operate, and other indoor units in the indoor unit group except the second indoor unit are controlled to stop operating, and the refrigerant discharged by the compressor is divided into two branches and passes through the first indoor expansion valve and the second indoor expansion valve respectively. The opening of the first indoor expansion valve is controlled to be adjusted to a preset opening, the equivalent passage area of the first indoor expansion valve at the preset opening can be obtained according to the opening-equivalent passage area fitting function corresponding to the first indoor expansion valve, and further, the refrigerant mass flow passing through the second indoor expansion valve can be obtained according to the main flow of the compressor and the refrigerant mass flow passing through the first indoor expansion valve, so as to obtain the opening-equivalent passage area fitting function corresponding to the second indoor expansion valve.

[0022] In some embodiments, the refrigerant circulation main loop of the multi-connected air conditioning system further comprises a gas-liquid separator arranged between the compressor and the four-way valve, the gas-liquid separator having an inlet in communication with the four-way valve and an outlet in communication with the suction port of the compressor; the multi-connected air conditioning system further comprises: a subcooling loop, one end of the subcooling loop being connected to the inlet of the gas-liquid separator, and the other end being connected between the outdoor heat exchanger and the indoor unit group in the refrigerant circulation main loop; the subcooling loop comprises a middle heat exchanger and a first expansion valve connected in series; in the process of obtaining the refrigerant mass flow rate of the refrigerant circulation main loop by the controller, the first expansion valve in the subcooling loop is in a closed state.

[0023] It can be understood that, in the process of obtaining the refrigerant mass flow rate of the refrigerant circulation main loop by the controller, the first expansion valve in the subcooling loop being in a closed state can make the refrigerant mass flow rate through the compressor be the main flow rate.

[0024] In some embodiments, the multi-connected air conditioning system further comprises: a refrigerant injection loop, one end of the refrigerant injection loop being connected to the suction port of the compressor, and the other end being connected between the outdoor heat exchanger and the indoor unit group in the refrigerant circulation main loop; the refrigerant injection loop comprises a middle heat exchanger and a second expansion valve connected in series; in the process of obtaining the refrigerant mass flow rate of the refrigerant circulation main loop by the controller, the second expansion valve is in a closed state.

[0025] It can be understood that, in the process of obtaining the refrigerant mass flow rate of the refrigerant circulation main loop by the controller, the second expansion valve being in a closed state can make the refrigerant mass flow rate through the compressor be the main flow rate.

[0026] In a second aspect, a control method of a multi-connected air conditioning system is provided, the method comprising: controlling a first indoor unit in an indoor unit group to operate, and other indoor units in the indoor unit group except the first indoor unit to stop operating; controlling an opening degree of a first indoor expansion valve to be adjusted to each of a plurality of first test opening degrees in turn, and obtaining a refrigerant mass flow rate of a refrigerant circulation main loop under each of the first test opening degrees in turn, the first indoor expansion valve being an indoor expansion valve in the first indoor unit; determining an equivalent passage area of the first indoor expansion valve under each of the first test opening degrees according to the refrigerant mass flow rate of the refrigerant circulation main loop under each of the first test opening degrees; and performing function fitting on the equivalent passage areas of the first indoor expansion valve under each of the first test opening degrees to obtain an opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve.

[0027] In some embodiments, the control method of the multi-split air conditioning system further comprises: after obtaining the opening-equivalent passage area fitting function corresponding to the first indoor expansion valve, controlling the first indoor unit and the second indoor unit to operate, and controlling other indoor units in the indoor unit group except the second indoor unit to stop operating; controlling the opening of the first indoor expansion valve to be adjusted to a preset opening, controlling the opening of the second indoor expansion valve to be adjusted to each of a plurality of second test openings in turn, and obtaining the refrigerant mass flow of the refrigerant circulating main loop under each of the second test openings in turn, the second indoor expansion valve being an indoor expansion valve in the second indoor unit; determining the refrigerant mass flow of the first indoor expansion valve according to the opening-equivalent passage area fitting function corresponding to the first indoor expansion valve and the preset opening; for each of the second test openings, taking the difference between the refrigerant mass flow of the refrigerant circulating main loop under the second test opening and the refrigerant command flow of the first indoor expansion valve as the refrigerant mass flow of the second indoor expansion valve under the second test opening; determining the equivalent passage area of the second indoor expansion valve under each of the second test openings according to the refrigerant mass flow of the second indoor expansion valve under each of the second test openings; and performing function fitting on the equivalent passage area of the second indoor expansion valve under each of the second test openings to obtain the opening-equivalent passage area fitting function corresponding to the second indoor expansion valve.

[0028] In a third aspect, an embodiment of the present application provides a controller, comprising: one or more processors; and one or more memories; wherein the one or more memories are configured to store computer program codes, the computer program codes comprising computer instructions, and when the one or more processors execute the computer instructions, the controller performs the control method provided in the second aspect.

[0029] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, the computer readable storage medium comprising computer instructions, and when the computer instructions are executed on a computer, the computer instructions cause the computer to perform the method provided in the second aspect and possible implementation manners.

[0030] In a fifth aspect, an embodiment of the present application provides a computer program product, the computer program product being directly loadable into a memory and containing software codes, and when the computer program product is loaded and executed by a computer, the computer program product can implement the method provided in the second aspect and possible implementation manners.

[0031] It should be noted that the above computer instructions can be stored on 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 can be packaged separately from the processor of the controller, and the present application does not limit the computer readable storage medium.

[0032] The beneficial effects of the second aspect to the fifth aspect described in the present application can be analyzed with reference to the beneficial effects of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A structural schematic diagram of a multi-connected air conditioning system provided for an embodiment of the present application;

[0034] Figure 2 A hardware structural schematic diagram of a controller provided for an embodiment of the present application;

[0035] Figure 3 A hardware structural schematic diagram of another controller provided for an embodiment of the present application;

[0036] Figure 4 A refrigeration cycle principle schematic diagram of a multi-connected air conditioning system provided for an embodiment of the present application;

[0037] Figure 5 A heating cycle principle schematic diagram of a multi-connected air conditioning system provided for an embodiment of the present application;

[0038] Figure 6 A structural schematic diagram of another multi-connected air conditioning system provided for an embodiment of the present application;

[0039] Figure 7 A structural schematic diagram of another multi-connected air conditioning system provided for an embodiment of the present application;

[0040] Figure 8 A flow schematic diagram of a control method of another multi-connected air conditioning system provided for an embodiment of the present application;

[0041] Figure 9 A flow schematic diagram of a control method of another multi-connected air conditioning system provided for an embodiment of the present application;

[0042] Figure 10 A flow schematic diagram of a control method of another multi-connected air conditioning system provided for an embodiment of the present application;

[0043] Figure 11 A hardware structural schematic diagram of a controller provided for an embodiment of the present application;

[0044] 11 - multi-connected air conditioning system; 100 - indoor unit; 100A - first indoor unit; 101A - first indoor heat exchanger; 102A - first indoor expansion valve; 100B - second indoor unit; 101B - second indoor heat exchanger; 102B - second indoor expansion valve; 200 - outdoor unit; 201 - outdoor heat exchanger; 202 - four-way valve; 203 - compressor; 204 - gas-liquid separator; 205 - oil separator; 206 - intermediate heat exchanger; 207 - first expansion valve; 208 - second expansion valve; 301 - outdoor control module; 302 - indoor control module; 303 - processor; 304 - memory; 305 - communication interface; 306 - bus. DETAILED DESCRIPTION

[0045] 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, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0046] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0047] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. 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 "a plurality of" is two or more.

[0048] In the description of the embodiments of the present application, it should be noted that unless otherwise 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 according to the specific circumstances. In addition, when describing the pipeline, the "connected" and "connected" used in the present application have the meaning of conducting. The specific meaning needs to be understood in combination with the context.

[0049] In the embodiments of the present application, the word "exemplary" or "for example" is used to mean serving as an example, instance, or illustration. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, use of the words "exemplary" or "for example" is intended to present concepts in a concrete manner.

[0050] As described in the background, the current pre-configured indoor expansion valve opening-equal passage area function of the multi-split air conditioning system is not accurate enough, which affects the fairness of the multi-split air conditioning system based on the opening-equal passage area function to achieve the sub-user billing.

[0051] To solve the above technical problems, the embodiments of the present application provide a multi-split air conditioning system and a control method thereof. The control method controls the first indoor unit to operate and the other indoor units in the indoor unit group to stop operating, so that the refrigerant mass flow rate of the refrigerant circulation main circuit is equivalent to the refrigerant mass flow rate of the indoor expansion valve of the first indoor unit. In this way, by continuously changing the indoor expansion valve in the first indoor unit, the refrigerant mass flow rate of the indoor expansion valve of the first indoor unit under different test openings can be obtained. Finally, through the refrigerant mass flow rates of the indoor expansion valve of the first indoor unit under multiple test openings, a fitting function of the opening-equal passage area that conforms to the actual situation can be fitted.

[0052] In the embodiments of the present application, the multi-split air conditioning system includes a refrigerant circulation main circuit. The refrigerant circulation main circuit includes a compressor, a four-way valve, an outdoor heat exchanger, and an indoor unit group connected in series. The indoor unit group includes multiple indoor units arranged side by side. Each indoor unit includes an indoor expansion valve and an indoor heat exchanger.

[0053] To further describe the technical solutions of the embodiments of the present application, as shown in Figure 1 FIG. 1 is a structural diagram of a multi-split air conditioning system provided by the embodiments of the present application.

[0054] Referring to Figure 1 The multi-split air conditioning system 11 includes an indoor unit group 100 and an outdoor unit 200.

[0055] In some embodiments, the indoor unit group 100 includes a first indoor unit 100A and a second indoor unit 100B connected in parallel.

[0056] The first indoor unit 100A includes a first indoor heat exchanger 101A and a first indoor expansion valve 102A.

[0057] The second indoor unit 100B includes a second indoor heat exchanger 101B and a second indoor expansion valve 102B.

[0058] In some embodiments, the outdoor unit 200 is usually arranged outdoors to assist the heat exchange of the indoor environment. The arrangement and functions of various components of the outdoor unit 200 are described in detail below.

[0059] In some embodiments, the outdoor unit 200 includes an outdoor heat exchanger 201, a four-way valve 202, a compressor 203, a gas-liquid separator 204, and an oil separator 205.

[0060] In some embodiments, the outdoor heat exchanger 201 is arranged in the outdoor unit 200 to exchange heat between the refrigerant flowing in the heat transfer pipe of the outdoor heat exchanger 201 and outdoor air.

[0061] In some embodiments, the four-way valve 202 has four ports, which are connected to the exhaust port of the compressor 203, the first indoor heat exchanger 101A, the suction port of the compressor 203, and the outdoor heat exchanger 201, respectively, to realize the mutual conversion between the cooling mode and the heating mode by changing the flow direction of the refrigerant in the system pipeline.

[0062] In some embodiments, the compressor 203 is arranged between the outdoor heat exchanger 201 and the indoor unit 100 to provide power for the refrigerant circulation. The exhaust port of the compressor 203 is connected to the first indoor heat exchanger 101A and the second indoor heat exchanger 101B in sequence through the oil separator 205 and the four-way valve 202; the suction port of the compressor 203 is connected to the outdoor heat exchanger 201 in sequence through the gas-liquid separator 204 and the four-way valve 202.

[0063] In some embodiments, the gas-liquid separator 204 is used to contain the refrigerant in the liquid return part of the refrigerant passage to prevent liquid impact on the compressor 203.

[0064] In some embodiments, the oil separator 205 is used to separate the lubricating oil in the high-pressure steam discharged by the compressor 203 to ensure the safe and efficient operation of the air conditioning system.

[0065] In some embodiments, the outdoor unit 200 further includes an outdoor unit fan (not shown in the figure), which generates an air flow of outdoor air through the outdoor heat exchanger 201 to promote the heat exchange between the refrigerant flowing in the heat transfer pipe of the outdoor heat exchanger 201 and the outdoor air.

[0066] In some embodiments, the outdoor unit 200 further includes an outdoor unit fan motor (not shown in the figure) connected to the outdoor unit fan to drive or change the rotation speed of the outdoor unit fan.

[0067] As Figure 2As shown, the multi-split air conditioning system also includes a controller 300, which is electrically connected to the first indoor heat exchanger 101A, the second indoor heat exchanger 101B, the first indoor expansion valve 102A, the second indoor expansion valve 102B, the outdoor heat exchanger 201, the four-way valve 202, the compressor 203, the gas-liquid separator 204, and the oil separator 205.

[0068] In some embodiments, controller 300 refers to a device that can generate operation control signals based on instruction opcodes and timing signals to instruct the multi-split air conditioning system to execute control instructions. Exemplarily, controller 300 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. Controller 300 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.

[0069] In addition, the controller 300 can be used to control the operation of each component in the multi-split air conditioning system 11 so that each component of the multi-split air conditioning system 11 can perform the predetermined functions of the air conditioning system.

[0070] Figure 3 This is a schematic diagram of the structure of a controller 300 provided in an embodiment of this application. Figure 3 As shown, the controller 300 includes an outdoor control module 301 and an indoor control module 302. The outdoor control module 301 includes a first memory, and the indoor control module 302 includes a second memory. The indoor control module 302 is connected to the outdoor control module 301 via wired or wireless communication. The outdoor control module 301 can be installed in the outdoor unit or independently of the outdoor unit, and is used to control the outdoor unit to perform related operations. The indoor control module 302 can be installed in the indoor unit or independently of the indoor unit, and is used to control the components of the indoor unit. It should be understood that the above module division is only functional; the outdoor control module 301 and the indoor control module 302 can also be integrated into one module. The first memory and the second memory can also be integrated into one memory.

[0071] In some embodiments, the first memory is configured to store application programs and data related to the outdoor unit, and the outdoor control module 301 performs various functions and data processing of the air conditioning system by running the application programs and data stored in the memory. The first memory mainly includes a program storage area and a data storage area. The program storage area can store an operating system and at least one application program required for a function (such as a regulation program for each expansion valve). The data storage area can store data created according to the use of the multi-split air conditioning system (such as the opening degree of each expansion valve). In addition, the first memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0072] In some embodiments, the second memory is configured to store application programs and data related to the indoor unit and each expansion valve, and the indoor control module 302 performs various functions and data processing of the multi-split air conditioning system by running the application programs and data stored in the memory. The second memory mainly includes a program storage area and a data storage area. The program storage area can store an operating system and at least one application program required for a function (such as a regulation program for each expansion valve). The data storage area can store data created according to the use of the multi-split air conditioning system (such as the opening degree of each expansion valve). In some examples, the second memory is also configured to store the correspondence between the address of the indoor unit and the address of each expansion valve.

[0073] In some embodiments, the outdoor control module 301 is in communication connection with the outdoor unit, and is configured to control the outdoor unit to perform related operations according to user instructions or system default instructions. Optionally, the outdoor control module 301 can control the opening degree of each expansion valve according to the compressor discharge superheat. Optionally, the outdoor control module 301 can also obtain the outdoor temperature according to user instructions or system instructions, and store the obtained outdoor temperature to the first memory. Optionally, the outdoor control module 301 can also control the four-way valve 202 in the outdoor unit 200 to rotate according to the air conditioning operation mode selected by the user, so as to realize the selection of the cooling mode or the heating mode. Optionally, the outdoor control module 301 can also control the operation mode, the compressor frequency, etc. of the outdoor unit during the address correction process.

[0074] In some embodiments, the indoor control module 302 is in communication connection with the indoor unit, and is configured to control the indoor unit to perform related operations according to user instructions or system default instructions. Optionally, the indoor control module 302 controls the opening degree of each expansion valve according to the compressor discharge superheat. Optionally, the indoor control module 302 can also detect the indoor temperature according to user instructions.

[0075] In some embodiments, the above-mentioned air conditioning system 11 has multiple working modes, such as a cooling mode and a heating mode.

[0076] The above refrigeration mode and heating mode will be introduced respectively in combination with the accompanying drawings of the specification.

[0077] 1. Refrigeration mode

[0078] When the air conditioning system is in the refrigeration mode, the first indoor heat exchanger 101A and the second indoor heat exchanger 101B work as evaporators, and the outdoor heat exchanger 201 works as a condenser.

[0079] Exemplarily, the above refrigeration mode is illustrated in combination with the multi-split air conditioning system 11 shown in Figure 4 FIG. 1.

[0080] When the multi-split air conditioning system 11 is in the refrigeration mode, the a end and the b end of the four-way valve 202 are connected, and the c end and the d end are connected. The compressor 203 discharges high-temperature and high-pressure gaseous refrigerant. The gaseous refrigerant discharged from the exhaust port of the compressor 203 is separated from the lubricating oil in the high-temperature and high-pressure steam through the oil separator 205. Then, the gaseous refrigerant successively passes through the c end and the d end of the four-way valve 202 to the outdoor heat exchanger 201. After being fully heat-exchanged in the outdoor heat exchanger 201, the gaseous refrigerant becomes high-temperature and high-pressure supercooled liquid refrigerant, and then is divided into multiple branches. Part of the refrigerant passes through the first indoor expansion valve 102A to the first indoor heat exchanger 101A, and another part of the refrigerant passes through the second indoor expansion valve 102B to the second indoor heat exchanger 101B. The refrigerant in multiple branches is respectively heat-exchanged in the indoor expansion valve, evaporated into low-temperature and low-pressure superheated gaseous refrigerant, and then successively passes through the b end and the a end of the four-way valve 202, flows through the gas-liquid separator 204, and enters the compressor 203 from the suction port of the compressor 203, to complete the refrigeration cycle.

[0081] 2. Heating mode

[0082] When the air conditioner is in the heating mode, the first indoor heat exchanger 101A and the second indoor heat exchanger 101B work as condensers, and the outdoor heat exchanger 201 works as an evaporator.

[0083] Exemplarily, the above heating mode is illustrated in combination with the multi-split air conditioning system 11 shown in Figure 5 FIG. 1.

[0084] When the air conditioning system 11 is in the heating mode, the a end of the four-way reversing valve 202 is connected with the d end, and the b end is connected with the c end. The compressor 203 discharges high-temperature and high-pressure gaseous refrigerant. The gaseous refrigerant discharged from the exhaust port of the compressor 203 is separated from the lubricating oil in the high-temperature and high-pressure steam through the oil separator 205. Then, the gaseous refrigerant is divided into multiple branches in sequence through the c end and the b end of the four-way valve 202. Part of the refrigerant flows through the first indoor heat exchanger 101A, and another part of the refrigerant flows through the second indoor heat exchanger 101B. Heat exchange occurs in the indoor heat exchanger, and the refrigerant is condensed into low-temperature and high-pressure subcooled liquid refrigerant. Then, the refrigerant enters the outdoor heat exchanger 201 to complete heat exchange, evaporates into low-temperature and low-pressure superheated gaseous refrigerant, and then flows through the gas-liquid separator 204 through the d end and the a end of the four-way reversing valve. The superheated gaseous refrigerant enters the compressor 203 from the suction port of the compressor 203, and completes the heating cycle.

[0085] In some embodiments, on the basis of the multi-split air conditioning system shown in Figure 1 As shown in Figure 6 The multi-split air conditioning system further comprises a subcooling circuit. The subcooling circuit comprises a middle heat exchanger 206 and a first expansion valve 207 connected in sequence. One end of the subcooling circuit is connected to the inlet of the gas-liquid separator 204, and the other end is connected between the outdoor heat exchanger 201 and the indoor unit 100. The middle heat exchanger 206 has a first pipeline. One end of the first pipeline is connected to the inlet of the gas-liquid separator 204, and the other end is connected to the first expansion valve 207. Optionally, the middle heat exchanger 206 further has a second pipeline. One end of the second pipeline is connected to the outdoor heat exchanger 201, and the other end is connected to the indoor unit 100.

[0086] The subcooling circuit can be used to divide part of the refrigerant and throttle it through the middle heat exchanger, exchange heat with the refrigerant in the main refrigerant circulation circuit, increase the subcooling degree of the refrigerant in the main refrigerant circulation circuit, prevent the refrigerant in the main refrigerant circulation circuit from flashing (flashing of the refrigerant before the throttle valve in the long connection pipe may cause failure of the throttle valve), and improve the system energy efficiency.

[0087] In some embodiments, on the basis of the multi-split air conditioning system shown in Figure 1 As shown in Figure 7As shown, the multi-split air conditioning system further comprises a refrigerant injection circuit. The refrigerant injection circuit comprises the intermediate heat exchanger 206 and the second expansion valve 208 connected in series, one end of the refrigerant injection circuit is connected to the suction port of the compressor 203, and the other end is connected between the outdoor heat exchanger 201 and the indoor unit 100. The intermediate heat exchanger 206 has a first pipeline, one end of the first pipeline is connected to the suction port of the compressor 203, and the other end is connected to the second expansion valve 208. Optionally, the intermediate heat exchanger 206 further has a second pipeline, one end of the second pipeline is connected to the outdoor heat exchanger 201, and the other end is connected to the indoor unit 100.

[0088] The refrigerant injection circuit is used to extract a part of the refrigerant to inject into the suction port of the compressor, which can improve the pressure ratio (similar to double-stage compression), increase the flow of the refrigerant in the main refrigerant circulation loop, and improve the heating capacity and operating energy efficiency of the heating operation in winter.

[0089] The control method of the multi-split air conditioning system provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0090] As shown in the Figure 8 The control method of the multi-split air conditioning system provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings. Figure 6 The method comprises the following steps:

[0091] S101, control the first indoor unit to operate, and control other indoor units in the indoor unit group except the first indoor unit to stop operating.

[0092] It should be noted that the first indoor unit can operate in a cooling mode or a heating mode.

[0093] In some embodiments, in order to realize accurate sub-metering for different working modes, the first indoor unit can have an opening-equivalent passage area fitting function in the cooling mode and an opening-equivalent passage area fitting function in the heating mode. Based on this, in order to obtain the opening-equivalent passage area fitting function in the cooling mode, the first indoor unit operates in the cooling mode to collect parameters for the fitting function in the cooling mode. In order to obtain the opening-equivalent passage area fitting function in the heating mode, the first indoor unit operates in the heating mode to collect parameters for the fitting function in the cooling mode.

[0094] S102, control the opening of the first indoor expansion valve to be adjusted to each of a plurality of first test openings in turn, and obtain the refrigerant mass flow of the main refrigerant circulation loop at each of the first test openings in turn, the first indoor expansion valve being an indoor expansion valve in the first indoor unit.

[0095] For example, the plurality of first test openings at least include a minimum opening, a 20% opening, a 40% opening, a 60% opening, an 80% opening, and a maximum opening. The minimum opening and the maximum opening of one expansion valve are related to the structure of the expansion valve, the control and measurement of the manufacturer, and other influencing factors. For example, the minimum opening can be 0 or 2%. The maximum opening can be 100% or 95%.

[0096] As a possible implementation, for each first test opening, after the expansion valve in the first chamber is adjusted to the first test opening, the rotation speed of the outdoor unit fan and / or the frequency of the compressor are adjusted so that the suction superheat of the compressor is greater than or equal to a preset value. After the suction superheat of the compressor is greater than or equal to the preset value, the refrigerant mass flow of the refrigerant circulation main loop at the first test opening is obtained. For example, the preset value is 5°C.

[0097] It should be understood that the suction superheat of the compressor refers to the difference between the suction temperature of the compressor and the evaporation temperature of the refrigerant. The suction superheat of the compressor exists to ensure that no liquid refrigerant enters the compressor to cause damage to the compressor. In addition, when the suction superheat of the compressor is too small, the refrigerant at the suction port of the compressor can be in a two-phase state. Since the enthalpy of the refrigerant in the two-phase state cannot be accurately calculated according to the energy balance method, in order to avoid the influence of the two-phase state of the refrigerant at the suction port of the compressor, the suction superheat of the compressor needs to be greater than or equal to the preset value to ensure the calculation accuracy of the energy balance method and the calibration accuracy of the household metering.

[0098] In some embodiments, the refrigerant mass flow of the refrigerant circulation main loop can be determined by the following steps:

[0099] S1, after the suction superheat of the compressor is greater than or equal to the preset value, the suction temperature, the suction pressure, the discharge temperature, the discharge pressure, the shell temperature, the ambient temperature, the shell surface area, and the power of the compressor are obtained.

[0100] S2, based on the suction temperature and the suction pressure, the suction refrigerant enthalpy h suc of the compressor is determined; based on the discharge temperature and the discharge pressure, the discharge refrigerant enthalpy h dis of the compressor is determined; and based on the shell temperature, the ambient temperature, and the shell surface area, the heat leakage Q loss of the compressor is determined.

[0101] It should be understood that the enthalpy of the refrigerant is related to the pressure and the temperature, so the suction refrigerant enthalpy of the compressor is determined based on the suction temperature and the suction pressure, and the discharge refrigerant enthalpy of the compressor is determined based on the discharge temperature and the discharge pressure.

[0102] As a possible implementation, the heat leakage of the compressor is determined by the following formula:

[0103] Q loss = Q conv + Q rad

[0104] wherein Q conv is the convective heat loss, and Q rad is the radiative heat loss.

[0105] Exemplarily, the convective heat loss and the radiative heat loss are determined by using the following equations:

[0106]

[0107]

[0108] wherein k conv,shell is the convective heat transfer coefficient between the compressor shell and the surrounding environment; A shell is the surface area of the compressor shell; t shell is the temperature of the compressor shell; t air is the temperature of the compressor environment; and σ is the Stefan-Boltzmann radiation constant, 5.67 x 10 -8 W / (m 2 K 4 .

[0109] Exemplarily, k conv,shell is determined by using the following equation:

[0110] k conv,shell = 9.4 + 0.052 (t shell - t air )

[0111] S3, based on the heat leakage, the compressor suction refrigerant enthalpy, the compressor discharge refrigerant enthalpy, and the power, determine the refrigerant mass flow rate of the refrigerant circulation main loop.

[0112] In some embodiments, the refrigerant mass flow rate M ri of the refrigerant circulation main loop satisfies the following relationship:

[0113] P + M ri h suc = M ri h dis + Q loss

[0114] wherein P is the power of the compressor.

[0115] In some embodiments, if the multi-split air conditioning system has a subcooling circuit, in order to accurately obtain the refrigerant mass flow rate of the main refrigerant circulation loop during the determination of the opening-equivalent channel area fitting function, it is necessary to cut off the subcooling circuit (i.e., the first expansion valve is closed), so that the refrigerant discharged from the compressor discharge port is not diverted by the subcooling circuit. Thus, the refrigerant mass flow rate calculated based on the aforementioned compressor parameters is equivalent to the refrigerant mass flow rate of the main refrigerant circulation loop.

[0116] In some embodiments, if the multi-split air conditioning system has a refrigerant injection circuit, in order to accurately obtain the refrigerant mass flow rate of the main refrigerant circulation loop during the process of determining the opening degree-equivalent channel area fitting function, it is necessary to cut off the refrigerant injection circuit (i.e., the second expansion valve is in the closed state), so that the refrigerant discharged from the compressor discharge port is not diverted by the refrigerant injection circuit. Thus, the refrigerant mass flow rate calculated based on the aforementioned compressor-related parameters is equivalent to the refrigerant mass flow rate of the main refrigerant circulation loop.

[0117] S103. Based on the refrigerant mass flow rate of the refrigerant circulation main circuit under each first test opening, determine the equivalent channel area of ​​the first indoor expansion valve under each first test opening.

[0118] As one possible approach, the equivalent channel area A of the first indoor expansion valve is determined using the following formula. vi :

[0119]

[0120] Among them, C Di p is the flow coefficient of the expansion valve. vi This indicates the inlet pressure of the indoor expansion valve; p vo Indicates the outlet pressure of the indoor expansion valve; v vi This indicates the refrigerant specific volume at the inlet of the indoor expansion valve.

[0121] For example, C is determined using the following formula. Di :

[0122]

[0123] Among them, v vo This represents the refrigerant specific volume at the outlet of the indoor expansion valve. a and b represent the correlation coefficients of the corresponding refrigerant properties; for example, s can be 0.02005 and b can be 6.34.

[0124] In some embodiments, the equivalent passage area of the first indoor expansion valve at different opening degrees should have a corresponding reasonable value range in the case that the first indoor expansion valve does not have serious dirt blockage. Therefore, whether the equivalent passage area of the first indoor expansion valve at each first test opening degree is within the corresponding reasonable value range can be detected. If the equivalent passage areas of the first indoor expansion valve at a preset number of first test opening degrees are not within the corresponding reasonable value ranges, the multi-split air conditioning system can prompt that the first indoor expansion valve has dirt blockage, so that the user can maintain the first indoor expansion valve.

[0125] S104, the equivalent passage area of the first indoor expansion valve at each first test opening degree is fitted to obtain an opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve.

[0126] The opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve is:

[0127] A vi =f(OP i )

[0128] Wherein, OP i is the opening degree of the indoor expansion valve.

[0129] Figure 8 The technical solutions shown at least bring the following beneficial effects: by controlling the first indoor unit to run and the other indoor units in the indoor unit group to stop running except the first indoor unit, the refrigerant mass flow of the refrigerant circulation main circuit is equivalent to the refrigerant mass flow of the indoor expansion valve of the first indoor unit. In this way, by continuously changing the indoor expansion valve in the first indoor unit, the refrigerant mass flow of the indoor expansion valve of the first indoor unit at different test opening degrees can be obtained. Finally, through the refrigerant mass flow of the indoor expansion valve of the first indoor unit at multiple test opening degrees, an opening degree-equivalent passage area fitting function that conforms to the actual situation can be fitted.

[0130] In some embodiments, based on Figure 8 The embodiments shown as shown in Figure 9 The control method of the multi-split air conditioning system further includes the following steps:

[0131] S105, after obtaining the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve, controlling the second indoor unit to run and the other indoor units in the indoor unit group to stop running except the second indoor unit.

[0132] Wherein, the second indoor unit is any one of the other indoor units in the indoor unit group except the first indoor unit.

[0133] S106, control the opening degree of the second indoor expansion valve to be adjusted to each of a plurality of second test opening degrees in turn, and obtain the refrigerant mass flow of the refrigerant circulation main loop under each of the second test opening degrees in turn, the second indoor expansion valve being an indoor expansion valve in the second indoor unit.

[0134] S107, determine the equivalent passage area of the second indoor expansion valve under each of the second test opening degrees according to the refrigerant mass flow of the refrigerant circulation main loop under each of the second test opening degrees.

[0135] S108, perform function fitting on the equivalent passage area of the second indoor expansion valve under each of the second test opening degrees to obtain an opening degree-equivalent passage area fitting function corresponding to the second indoor expansion valve.

[0136] Figure 9 The technical solutions shown at least bring the following beneficial effects: by controlling the second indoor unit to run and the other indoor units in the indoor unit group except the second indoor unit to stop running, the refrigerant mass flow of the refrigerant circulation main loop is equivalent to the refrigerant mass flow of the indoor expansion valve of the second indoor unit. In this way, by continuously changing the indoor expansion valve in the second indoor unit, the refrigerant mass flow of the indoor expansion valve of the second indoor unit under different test opening degrees can be obtained. Finally, by the refrigerant mass flow of the indoor expansion valve of the second indoor unit under a plurality of test opening degrees, an opening degree-equivalent passage area fitting function conforming to the actual situation can be fitted.

[0137] In other embodiments, based on Figure 8 The embodiments shown as above, such as Figure 10 The control method of the multi-split air conditioning system shown as above further includes the following steps:

[0138] S109, after obtaining the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve, control the first indoor unit and the second indoor unit to run and control the other indoor units in the indoor unit group except the first indoor unit and the second indoor unit to stop running.

[0139] S110, control the opening degree of the first indoor expansion valve to be adjusted to a preset opening degree, control the opening degree of the second indoor expansion valve to be adjusted to each of a plurality of second test opening degrees in turn, and obtain the refrigerant mass flow of the refrigerant circulation main loop under each of the second test opening degrees in turn, the second indoor expansion valve being an indoor expansion valve in the second indoor unit.

[0140] S111, determine the refrigerant mass flow of the first indoor expansion valve according to the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve and the preset opening degree.

[0141] S112, for each second test opening degree, taking the difference between the refrigerant mass flow of the refrigerant circulation main loop at the second test opening degree and the refrigerant command flow of the first indoor expansion valve as the refrigerant mass flow of the second indoor expansion valve at the second test opening degree.

[0142] S113, determining the equivalent passage area of the second indoor expansion valve at each second test opening degree according to the refrigerant mass flow of the second indoor expansion valve at each second test opening degree.

[0143] S114, function fitting the equivalent passage area of the second indoor expansion valve at each second test opening degree to obtain an opening degree-equivalent passage area fitting function corresponding to the second indoor expansion valve.

[0144] Figure 10 The technical solutions shown at least bring the following beneficial effects: after obtaining the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve, the equivalent passage area of the corresponding opening degree of the first indoor expansion valve can be obtained according to the fitting function. At this time, the second indoor unit is controlled to run, and other indoor units in the indoor unit group except the second indoor unit are controlled to stop running, and the refrigerant discharged by the compressor is divided into two branches to pass through the first indoor expansion valve and the second indoor expansion valve respectively. The opening degree of the first indoor expansion valve is controlled to be adjusted to a preset angle, the equivalent passage area of the first indoor expansion valve at the preset opening degree can be obtained according to the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve, and further, the refrigerant mass flow passing through the second indoor expansion valve can be obtained according to the refrigerant mass flow of the refrigerant circulation main loop and the refrigerant mass flow passing through the first indoor expansion valve, so as to obtain the opening degree-equivalent passage area fitting function corresponding to the second indoor expansion valve.

[0145] In some embodiments, if the ratio between the internal volume of the indoor heat exchanger in the second indoor unit and the internal volume of the outdoor heat exchanger is less than or equal to a preset ratio, allowing only the second indoor unit to run and prohibiting other indoor units to run will cause the entire multi-split air conditioning system to be in a low load running state, thereby affecting the accuracy of the refrigerant mass flow of the refrigerant circulation main loop obtained in the subsequent process, and further affecting the accuracy of the opening degree-equivalent passage area fitting function of the indoor expansion valve of the second indoor unit. Based on this, when the ratio between the internal volume of the indoor heat exchanger in the second indoor unit and the internal volume of the outdoor heat exchanger is less than or equal to the preset ratio, the technical solutions shown in the first aspect of the present application can be used to determine the opening degree-equivalent passage area fitting function of the indoor expansion valve of the second indoor unit. Figure 10 When the ratio between the internal volume of the indoor heat exchanger in the second indoor unit and the internal volume of the outdoor heat exchanger is greater than the preset ratio, the technical solutions shown in the second aspect of the present application can be used to determine the opening degree-equivalent passage area fitting function of the indoor expansion valve of the second indoor unit. Figure 9 When the ratio between the internal volume of the indoor heat exchanger in the second indoor unit and the internal volume of the outdoor heat exchanger is greater than the preset ratio, the technical solutions shown in the second aspect of the present application can be used to determine the opening degree-equivalent passage area fitting function of the indoor expansion valve of the second indoor unit.

[0146] It should be understood that the other indoor units in the indoor unit group can be determined by the method shown in the above Figure 9 Or Figure 10 the opening degree-equivalent passage area fitting function of the indoor expansion valve in the indoor unit.

[0147] It can be seen that the above mainly introduces the scheme provided by the embodiments of the present application from the perspective of method. To achieve the above functions, the embodiments of the present application provide the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, in combination with the modules and algorithm steps of the examples described in the embodiments disclosed in the present text, the embodiments of the present application can be realized in the form of hardware or the combination of hardware and computer software. Whether a certain function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0148] The embodiments of the present application can divide the functional modules of the controller according to the above method examples, for example, each functional module can be divided according to each function, or two or more functions can be integrated in one processing module. The above integrated module can be realized in the form of hardware or software functional module. Optionally, the division of the modules in the embodiments of the present application is illustrative, and is only a logical functional division. When actually implemented, there can be another division manner.

[0149] The embodiments of the present application also provide a hardware structure diagram of a controller, as shown in Figure 11 The controller 300 further includes a processor 303, and optionally further includes a memory 304 and a communication interface 305 connected with the processor 303. The processor 303, the memory 304 and the communication interface 305 are connected through a bus 306.

[0150] The processor 303 can be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 303 can also be other devices with processing capabilities, such as a circuit, a device, or a software module. The processor 303 can also include multiple CPUs, and the processor 303 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 (e.g., computer program instructions).

[0151] The memory 304 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 carrying or storing desired program code in the form of instructions or data structures and that can be accessed by a computer, without limitation. The memory 304 can exist independently or be integrated with the processor 303. The memory 304 can include computer program code. The processor 303 is configured to execute the computer program code stored in the memory 304, thereby implementing the control method provided by the embodiments of the present application.

[0152] The communication interface 305 can be configured to communicate with other devices or communication networks (e.g., Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc.). The communication interface 305 can be a module, a circuit, a transceiver, or any device capable of communication.

[0153] The bus 306 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 306 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 11 Only one thick line is used in the figure to represent the bus, but it does not mean that there is only one bus or only one type of bus.

[0154] The embodiment of the present application further provides a computer readable storage medium comprising computer execution instructions, which, when running on a computer, causes the computer to execute the control method of the air conditioning system provided in any of the above embodiments.

[0155] The embodiment of the present application further provides a computer program product comprising computer execution instructions, which, when running on a computer, causes the computer to execute the control method of the air conditioning system provided in any of the above embodiments.

[0156] In the above embodiments, all or part of the embodiments can be realized by software, hardware, firmware or any combination thereof. When realized by software, all or part of the embodiments can be realized in the form of a computer program product. The computer program product comprises one or more computer execution instructions. When the computer execution instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer execution instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer execution instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer readable storage medium can be any available medium that can be accessed by a computer or data storage device comprising one or more servers, data centers, etc. integrated with the medium. The available medium can be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)), etc.

[0157] Although the application has been described in connection with the embodiments thereof with reference to the various drawings, it will be apparent to those of ordinary skill in the art that variations in the embodiments can be used and that it is not intended to limit the application to the particular form described. From the above discussion and illustrations, one skilled in the art will readily develop variations in the embodiments without departing from the spirit and scope of the application. Accordingly, the application is not limited by the specific examples described herein, but only by the claims that follow, the intent being to cover all modifications and equivalents falling within the spirit and scope of the application. Various features and aspects of the application are set forth with reference to the Figures, and each reference link is a part of the specification. Definitions for certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art will understand that terms, such as "including", "comprising", "consisting of", and "substantially" are not intended to exclude other additives, components, elements, or steps. Throughout this specification, ordinal numbers such as "first", "second", "third", etc. are used merely for differentiating between similar objects, and do not necessarily imply a sequential order or a particular chronology. The mere fact that measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0158] Although the application has been described in connection with specific embodiments thereof, it will be evident for those skilled in the art that various modifications and combinations are possible without departing from the scope of the application. Accordingly, the description and drawings are to be regarded as illustrative in nature and are not to be taken as limiting the scope of the application as defined by the appended claims. Obviously, many modifications and variations of this application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the claims and their equivalents, the application can be practiced otherwise than as specifically described. Thus, the application should be understood to include all alternatives and modifications to the associated methods and structures as set forth above, with the only limits being imposed by the claims and equivalents thereof.

[0159] The above description is only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed by 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. A multi-split air conditioning system, characterized in that, The system comprises: a refrigerant circulation main loop comprising, in series, a compressor, a four-way valve, an outdoor heat exchanger, and an indoor unit group comprising multiple indoor units arranged side by side, each indoor unit comprising an indoor expansion valve and an indoor heat exchanger; a controller configured to: control a first indoor unit to operate, and other indoor units in the indoor unit group except the first indoor unit to stop operating; control an opening degree of a first indoor expansion valve to be adjusted to each of multiple first test opening degrees in turn, the first indoor expansion valve being an indoor expansion valve in the first indoor unit, and obtain refrigerant mass flow rates of the refrigerant circulation main loop at the first test opening degrees in turn, wherein for each first test opening degree, after the first indoor expansion valve is adjusted to the first test opening degree, the rotational speed of an outdoor unit fan and / or the frequency of the compressor are adjusted so that the suction superheat degree of the compressor is greater than or equal to a preset value, and the refrigerant mass flow rate of the refrigerant circulation main loop at the first test opening degree is obtained after the suction superheat degree of the compressor is greater than or equal to the preset value; determine equivalent passage areas of the first indoor expansion valve at the first test opening degrees according to the refrigerant mass flow rates of the refrigerant circulation main loop at the first test opening degrees; and perform function fitting on the equivalent passage areas of the first indoor expansion valve at the first test opening degrees to obtain an opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve.

2. The multi-split air conditioning system according to claim 1, wherein the controller is configured to obtain the refrigerant mass flow rate of the refrigerant circulation main loop at the first test opening degree after the suction superheat degree of the compressor is greater than or equal to the preset value, and specifically perform the following steps: obtain the suction temperature, suction pressure, discharge temperature, discharge pressure, shell temperature, ambient temperature, shell surface area, and power of the compressor after the suction superheat degree of the compressor is greater than or equal to the preset value; determine the suction refrigerant enthalpy of the compressor based on the suction temperature and the suction pressure; determine the discharge refrigerant enthalpy of the compressor based on the discharge temperature and the discharge pressure; determine the heat leakage of the compressor based on the shell temperature, the ambient temperature, and the shell surface area; determine the refrigerant mass flow rate of the refrigerant circulation main loop based on the heat leakage, the suction refrigerant enthalpy of the compressor, the discharge refrigerant enthalpy of the compressor, and the power.

3. The multi-split air conditioning system according to any one of claims 1 to 2, wherein the controller is further configured to: after obtaining the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve, control a second indoor unit to operate, and control other indoor units in the indoor unit group except the second indoor unit to stop operating. The opening degree of the second indoor expansion valve is adjusted to each of a plurality of second test opening degrees in sequence, and the refrigerant mass flow of the refrigerant circulation main loop under each of the second test opening degrees is obtained in sequence, the second indoor expansion valve being an indoor expansion valve in the second indoor unit; According to the refrigerant mass flow of the refrigerant circulation main loop under each of the second test opening degrees, the equivalent passage area of the second indoor expansion valve under each of the second test opening degrees is determined; The equivalent passage areas of the second indoor expansion valve under each of the second test opening degrees are functionally fitted to obtain an opening degree-equivalent passage area fitting function corresponding to the second indoor expansion valve.

4. The multi-split air conditioning system according to claim 3, wherein, The ratio between the internal volume of the indoor heat exchanger in the second indoor unit and the internal volume of the outdoor heat exchanger is greater than a preset ratio.

5. The multi-split air conditioning system according to any one of claims 1 to 2, wherein The controller is further configured to: After obtaining the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve, control the first indoor unit and the second indoor unit to operate, and control other indoor units in the indoor unit group other than the first indoor unit and the second indoor unit to stop operating; The opening degree of the first indoor expansion valve is adjusted to a preset opening degree, and the opening degree of the second indoor expansion valve is adjusted to each of a plurality of second test opening degrees in sequence, and the refrigerant mass flow of the refrigerant circulation main loop under each of the second test opening degrees is obtained in sequence, the second indoor expansion valve being an indoor expansion valve in the second indoor unit; According to the opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve and the preset opening degree, the refrigerant mass flow of the first indoor expansion valve is determined; For each of the second test opening degrees, the difference between the refrigerant mass flow of the refrigerant circulation main loop under the second test opening degree and the refrigerant command flow of the first indoor expansion valve is taken as the refrigerant mass flow of the second indoor expansion valve under the second test opening degree; According to the refrigerant mass flow of the second indoor expansion valve under each of the second test opening degrees, the equivalent passage area of the second indoor expansion valve under each of the second test opening degrees is determined; The equivalent passage areas of the second indoor expansion valve under each of the second test opening degrees are functionally fitted to obtain an opening degree-equivalent passage area fitting function corresponding to the second indoor expansion valve. 6.The multi-split air conditioning system according to claim 5, characterized in that, The ratio between the internal volume of the indoor heat exchanger in the second indoor unit and the internal volume of the outdoor heat exchanger is less than or equal to a preset ratio. 7.The multi-split air conditioning system according to claim 1, characterized in that, The refrigerant circulation main loop further comprises a gas-liquid separator arranged between the compressor and the four-way valve, the gas-liquid separator having an inlet in communication with the four-way valve and an outlet in communication with a suction port of the compressor; The multi-split air conditioning system further comprises: A subcooling circuit, one end of the subcooling circuit being connected to the inlet of the gas-liquid separator, and the other end being connected between the outdoor heat exchanger and the indoor unit group in the refrigerant circulation main loop; the subcooling circuit comprising an intermediate heat exchanger and a first expansion valve connected in sequence; In the process that the controller acquires the refrigerant mass flow rate of the refrigerant circulation main loop, the first expansion valve in the subcooling loop is in a closed state. 8.The multi-split air conditioning system according to claim 1, characterized in that, The multi-split air conditioning system further comprises: A refrigerant injection circuit, one end of which is connected to a suction port of the compressor, and the other end of which is connected between the outdoor heat exchanger and the indoor unit in the refrigerant circulation main loop; the refrigerant injection circuit comprises, in series, an intermediate heat exchanger and a second expansion valve; In the process that the controller acquires the refrigerant mass flow rate of the refrigerant circulation main loop, the second expansion valve is in a closed state.

9. A control method of a multi VRF system, characterized by, The method comprises: Controlling a first indoor unit in the indoor unit group to operate, and other indoor units in the indoor unit group except the first indoor unit to stop operating; Controlling an opening degree of a first indoor expansion valve to be adjusted to each of a plurality of first test opening degrees in turn, the first indoor expansion valve being an indoor expansion valve in the first indoor unit; the refrigerant circulation main loop comprising, in series, a compressor, a four-way valve, an outdoor heat exchanger, and an indoor unit group, the indoor unit group comprising a plurality of indoor units arranged side by side, each indoor unit comprising an indoor expansion valve and an indoor heat exchanger; for each first test opening degree, after the first indoor expansion valve is adjusted to the first test opening degree, the rotational speed of an outdoor fan and / or the frequency of the compressor are adjusted so that the suction superheat degree of the compressor is greater than or equal to a preset value; after the suction superheat degree of the compressor is greater than or equal to the preset value, the refrigerant mass flow rate of the refrigerant circulation main loop at the first test opening degree is acquired; According to the refrigerant mass flow rates of the refrigerant circulation main loop at the respective first test opening degrees, equivalent passage areas of the first indoor expansion valve at the respective first test opening degrees are determined; The equivalent passage areas of the first indoor expansion valve at the respective first test opening degrees are subjected to function fitting, to obtain an opening degree-equivalent passage area fitting function corresponding to the first indoor expansion valve.

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