A multi-split system, a control method and a storage medium

Abstract

The application relates to a multi-connected system, a control method and a storage medium, the system comprising: a refrigerant circuit, a first reversing assembly and a second reversing assembly; the refrigerant circuit comprising a compressor, an outdoor heat exchanger and a terminal device group; the first reversing assembly comprising at least two parallelly arranged flow regulating valves, at least one flow regulating valve being connected between an exhaust port of the compressor and the terminal device group, and at least one flow regulating valve being connected between the terminal device group and a suction port of the compressor; the second reversing assembly comprising at least two parallelly arranged flow regulating valves, at least one flow regulating valve being connected between the exhaust port of the compressor and the outdoor heat exchanger, and at least one flow regulating valve being connected between the outdoor heat exchanger and the suction port of the compressor; the outdoor heat exchanger being connected with the terminal device group; by controlling the flow regulating valves, the flow direction of the refrigerant in the refrigerant circuit is adjusted, so that the working mode of the multi-connected system is switched. The application meets the design requirements of miniaturization and compactness of the multi-connected system.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to a multi-split air conditioning system, control method and storage medium. Background Technology

[0002] In existing multi-split air conditioning systems, four-way valves are typically used as switching mechanisms to change the flow direction of refrigerant within the refrigerant circuit, enabling switching between multiple modes. However, four-way valves are relatively large, and multiple valves are often required to meet the multi-functional tri-generation needs of multi-split systems. Traditional integrated four-way valves, while highly integrated, are also bulky, limiting their placement within compact outdoor units and hindering their ability to meet the miniaturization and compact design requirements of multi-split systems. Summary of the Invention

[0003] This application provides a multi-split air conditioning system, a control method, and a storage medium to solve the problem that the four-way valve in existing multi-split air conditioning systems is bulky and has limited layout in compact outdoor units.

[0004] In a first aspect, this application provides a multi-split air conditioning system, including: a refrigerant circuit, a first commutation assembly, and a second commutation assembly; The refrigerant circuit includes a compressor, an outdoor heat exchanger, and a terminal equipment group; The first reversing assembly includes at least two flow regulating valves arranged in parallel, at least one of the flow regulating valves being connected to the discharge port of the compressor and the terminal equipment group, and at least one of the flow regulating valves being connected to the terminal equipment group and the suction port of the compressor; The second reversing assembly includes at least two flow regulating valves arranged in parallel, at least one of the flow regulating valves is connected to the exhaust port of the compressor and the outdoor heat exchanger, and at least one of the flow regulating valves is connected to the outdoor heat exchanger and the intake port of the compressor. The outdoor heat exchanger is connected to the terminal equipment group; By controlling each of the aforementioned flow regulating valves, the flow direction of the refrigerant in the refrigerant circuit is adjusted to switch the operating mode of the multi-split system.

[0005] Secondly, this embodiment provides a control method for a multi-split air conditioning system, applied to the multi-split air conditioning system described above, the method comprising: The system obtains the operating mode that the multi-split air conditioning system needs to switch to, the outdoor ambient temperature of the outdoor environment where the multi-split air conditioning system is located, and the system pressure information corresponding to the multi-split air conditioning system. Based on the operating mode, the target operating state of each flow regulating valve included in the first reversing assembly and the second reversing assembly is determined. For each flow control valve whose target operating state is non-adjustment state, the opening degree of the flow control valve is controlled based on the target operating state of the flow control valve; For each flow regulating valve whose target operating state is the adjustment state, the opening degree of the flow regulating valve is controlled based on the operating mode, the outdoor ambient temperature, and the system pressure information, so that the multi-split system switches to the operating mode.

[0006] Thirdly, this embodiment provides a multi-unit air conditioning system, including a processor and a memory. The processor is used to execute a control program for the multi-unit air conditioning system stored in the memory to implement the control method for the multi-unit air conditioning system as described above.

[0007] Fourthly, this embodiment provides a storage medium that stores one or more programs, which can be executed by one or more processors to implement the control method of the multi-unit system as described above.

[0008] Compared with the prior art, the technical solution provided in this application has the following advantages. The multi-split air conditioning system provided in this application includes: a refrigerant circuit, a first reversing assembly, and a second reversing assembly; the refrigerant circuit includes a compressor, an outdoor heat exchanger, and a terminal equipment group; the first reversing assembly includes at least two flow regulating valves arranged in parallel, at least one flow regulating valve connecting the compressor's discharge port to the terminal equipment group, and at least one flow regulating valve connecting the terminal equipment group to the compressor's suction port; the second reversing assembly includes at least two flow regulating valves arranged in parallel, at least one flow regulating valve connecting the compressor's discharge port to the outdoor heat exchanger, and at least one flow regulating valve connecting the outdoor heat exchanger to the compressor's suction port; the outdoor heat exchanger is connected to the terminal equipment group; by controlling each flow regulating valve, the flow direction of the refrigerant in the refrigerant circuit is adjusted to switch the operating mode of the multi-split air conditioning system. In this embodiment, by setting a first reversing assembly and a second reversing assembly consisting of at least two parallel flow regulating valves, respectively connected between the compressor exhaust port and the terminal equipment group, between the terminal equipment group and the compressor suction port, between the compressor exhaust port and the outdoor heat exchanger, and between the outdoor heat exchanger and the compressor suction port, the traditional four-way valve reversing mechanism used for mode switching in multi-split systems is replaced. Thus, by utilizing the compact structure and flexible layout of the flow regulating valve itself, the space occupied by the reversing assembly inside the outdoor unit is reduced, avoiding the problems of pipeline congestion and large unit size caused by using multiple large-size four-way valves. This enables the multi-split system to achieve switching control of multiple working modes such as tri-generation within a limited space, meeting the design requirements of miniaturization and compactness of multi-split systems. Attached Figure Description

[0009] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0012] Figure 1 A schematic diagram of a multi-unit air conditioning system provided in an embodiment of this application; Figure 2 A flowchart illustrating a control method for a multi-unit air conditioning system provided in an embodiment of this application; Figure 3 A flowchart illustrating another control method for a multi-unit air conditioning system provided in this application embodiment; Figure 4 This is a schematic diagram of another multi-unit system provided in an embodiment of this application. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0014] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0015] refer to Figure 1 , Figure 1This is a schematic diagram of a multi-split air conditioning system provided in an embodiment of this application. The multi-split air conditioning system provided in this embodiment is an energy-saving system. A multi-split air conditioning system refers to an air conditioning system consisting of one or more indoor units connected to multiple indoor units and other functional terminal devices (such as water heaters and underfloor heating heat exchangers). It can operate in different working modes by controlling the refrigerant flow and direction according to the actual needs of each terminal device. The multi-split air conditioning system includes: a refrigerant circuit 10, a first commutation assembly 20, and a second commutation assembly 30.

[0016] The refrigerant circuit 10 is the circulation pipeline in the multi-split air conditioning system. It serves as the carrier for refrigerant flow, transportation, and heat exchange. The refrigerant circulates among the components in the refrigerant circuit 10, thereby completing the heat absorption and release cycle of the multi-split air conditioning system and providing the basic conditions for its cooling and heating regulation operation. The refrigerant circuit 10 includes a compressor 11, an outdoor heat exchanger 12, and a terminal equipment group 13. The compressor 11 is the power component for the refrigerant circulation in the refrigerant circuit 10. It compresses and increases the pressure of the refrigerant in the refrigerant circuit 10, changing its pressure and temperature, driving the refrigerant to circulate continuously throughout the entire refrigerant circuit 10, and ensuring stable operation of the heat exchange cycle.

[0017] The outdoor heat exchanger 12 is installed on the outdoor side and serves as a heat exchange component between the multi-split system and the external environment. It can switch between heat dissipation and heat absorption according to the working mode. In the cooling mode, it releases refrigerant heat to the outdoor environment, and in the heating mode, it absorbs heat from the outdoor environment, thus completing the external exchange of cold and heat energy.

[0018] Terminal equipment group 13 refers to a collection of terminal equipment installed on the user side for directly regulating indoor ambient temperature or producing hot water. Terminal equipment group 13 is connected to outdoor heat exchanger 12. Terminal equipment group 13 includes multiple terminal equipment arranged in parallel, each terminal equipment being connected to outdoor heat exchanger 12 via an on / off valve. The terminal equipment includes indoor unit, water heater, and underfloor heating heat exchanger. Figure 1 In the indoor unit, 131 indicates the indoor unit. Figure 1 The number 132 in the diagram represents a water heater or underfloor heating heat exchanger. Each of the aforementioned on-off valves has only two operating states: fully open or fully closed. The opening degree of each on-off valve cannot be continuously adjusted; its function is solely to connect or disconnect the refrigerant flow in its respective branch. When a terminal device needs to operate, its connected on-off valve is fully opened, allowing refrigerant to flow into the terminal device for heat exchange; when the terminal device does not need to operate, its connected on-off valve is fully closed, cutting off the refrigerant supply. This embodiment, by configuring independent on-off valves for each parallel terminal device, achieves independent control of refrigerant distribution on demand without interference, reducing the cost of multi-split systems while avoiding the risk of freezing caused by refrigerant flowing into shut-down terminal devices.

[0019] Furthermore, all on / off valves are solenoid valves. This embodiment further defines the on / off valves as solenoid valves, enabling refrigerant on / off control of each terminal device to be achieved through low-cost, technologically mature, and rapidly responsive solenoid valves. Compared to electronic expansion valves, solenoid valves have a simpler structure, lower price, and more stable and reliable switching action, further reducing the overall cost of the multi-split system while ensuring the real-time performance and accuracy of independent start / stop control for each terminal device.

[0020] The first reversing assembly 20 includes at least two flow regulating valves arranged in parallel. At least one flow regulating valve is connected to the discharge port of the compressor 11 and the terminal equipment group 13, and at least one flow regulating valve is connected to the suction port of the compressor 11. The first reversing assembly 20 is used to switch the flow direction of the refrigerant between the terminal equipment group 13 and the compressor 11. At least one flow regulating valve in the first reversing assembly 20 is connected to the discharge port of the compressor 11 and the high-pressure side and low-pressure side of the terminal equipment group 13. At least one flow regulating valve in the second reversing assembly 30 is connected to the low-pressure side of the terminal equipment group 13 and the suction port of the compressor 11. By controlling the opening degree of each flow regulating valve in the first reversing assembly 20, the flow direction of the refrigerant in the terminal equipment group 13 can be changed, thereby determining whether the terminal equipment group 13 acts as a condenser for heat release or as an evaporator for heat absorption. When the terminal equipment group 13 needs to act as a condenser, the flow regulating valve connecting the exhaust port of the compressor 11 to the terminal equipment group 13 is opened, and the flow regulating valve connecting the terminal equipment group 13 to the suction port of the compressor 11 is closed, allowing the high-temperature exhaust gas to enter the terminal equipment group 13 for condensation and heat release. When the terminal equipment group 13 needs to act as an evaporator, the flow regulating valve connecting the exhaust port of the compressor 11 to the terminal equipment group 13 is closed, and the flow regulating valve connecting the terminal equipment group 13 to the suction port of the compressor 11 is opened, allowing the low-temperature gas evaporated in the terminal equipment group 13 to flow back to the suction port of the compressor 11 through the flow regulating valve. This realizes the refrigerant flow direction switching function of a traditional four-way valve, enabling the multi-split system to flexibly switch between different operating modes.

[0021] Furthermore, when the terminal devices include indoor units, water heaters, and underfloor heating heat exchangers, at least one flow regulating valve in the first reversing assembly 20 connects the exhaust port of the compressor 11 to the indoor unit, water heater, and underfloor heating heat exchanger in the terminal device group 13; at least one flow regulating valve in the first reversing assembly 20 connects the indoor unit in the terminal device group 13 to the suction port of the compressor 11. The indoor unit is a low-pressure gas-side terminal device, while the water heater and underfloor heating heat exchanger are high-pressure gas-side terminal devices. This embodiment distinguishes the terminal devices as indoor units, water heaters, and underfloor heating heat exchangers, and connects the flow regulating valves in the first reversing assembly 20 according to terminal type. The exhaust port of the compressor 11 is simultaneously connected to all terminal devices in the terminal device group 13 to meet heating requirements, while the suction port of the compressor 11 is only connected to the indoor unit to meet cooling return gas requirements. This achieves physical separation of condensing terminal devices and reversible terminal devices at the refrigerant interface, enabling the multi-split system to support multiple functions operating in parallel with a simple piping structure.

[0022] In this embodiment, the first reversing assembly 20 includes a first flow regulating valve 21 and a second flow regulating valve 22, which are connected in parallel. The two ends of the first flow regulating valve 21 are respectively connected to the exhaust port of the compressor 11 and the terminal equipment group 13, and the two ends of the second flow regulating valve 22 are respectively connected to the terminal equipment group 13 and the suction port of the compressor 11. Specifically, the two ends of the first flow regulating valve 21 are respectively connected to the exhaust port of the compressor 11 and the high-pressure side and low-pressure side of the terminal equipment group 13, and the two ends of the second flow regulating valve 22 are respectively connected to the low-pressure side of the terminal equipment group 13 and the suction port of the compressor 11. That is, when the terminal equipment includes an indoor unit, a water heater, and a floor heating heat exchanger, the two ends of the first flow regulating valve 21 are respectively connected to the exhaust port of the compressor 11 and the indoor unit, water heater, and floor heating heat exchanger, and the two ends of the first flow regulating valve 21 are respectively connected to the suction port of the compressor 11 and the indoor unit. The first flow regulating valve 21 controls the refrigerant flow direction between the discharge port of the compressor 11 and the terminal equipment group 13. When the first flow regulating valve 21 is opened, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor 11 can enter the terminal equipment group 13 through this valve, and be used by the terminal equipment as a condenser. The second flow regulating valve 22 controls the refrigerant flow direction between the terminal equipment group 13 and the suction port of the compressor 11. When the second flow regulating valve 22 is opened, the low-temperature and low-pressure refrigerant generated by the terminal equipment group 13 as an evaporator flows back to the compressor 11. In this embodiment, by specifying the first reversing component 20 as two parallel and clearly defined flow regulating valves, and replacing the traditional integrated four-way valve with an independent valve body, not only is the cost of the multi-split system reduced, but the volume of the reversing mechanism is also reduced, making the pipeline layout more compact and flexible.

[0023] In the above description, the first flow regulating valve 21 and the second flow regulating valve 22 in the first reversing assembly 20 are both electronic expansion valves. Because electronic expansion valves are compact and have continuously adjustable openings, by limiting the first flow regulating valve 21 and the second flow regulating valve 22 in the first reversing assembly 20 to electronic expansion valves, a compact structure replaces the traditional large-size four-way valve to complete the refrigerant flow path switching. This meets the design requirements for miniaturized layouts in multi-split systems, while also providing fine-tuning of refrigerant flow and eliminating the mechanical impact noise generated by the four-way valve's pressure differential reversal.

[0024] The second reversing assembly 30 includes at least two flow regulating valves arranged in parallel. At least one flow regulating valve is connected to the discharge port of the compressor 11 and the outdoor heat exchanger 12, and at least one flow regulating valve is connected to the outdoor heat exchanger 12 and the suction port of the compressor 11. The second reversing assembly 30 is used to switch the refrigerant flow direction between the compressor 11 and the outdoor heat exchanger 12. One end of at least one flow regulating valve in the second reversing assembly 30 is connected to the high-pressure pipeline where the discharge port of the compressor 11 is located, and the other end is connected to the refrigerant port of the outdoor heat exchanger 12, forming a corresponding branch for supplying high-temperature, high-pressure refrigerant from the compressor 11 to the outdoor heat exchanger 12. Simultaneously, one end of at least one flow regulating valve in the second reversing assembly 30 is connected to the refrigerant port of the outdoor heat exchanger 12, and the other end is connected to the low-pressure pipeline where the suction port of the compressor 11 is located, forming a corresponding branch for the return of low-temperature, low-pressure refrigerant from the outdoor heat exchanger 12 to the compressor 11. By controlling the opening degree of each flow regulating valve in the second reversing assembly 30, the heat exchange role of the outdoor heat exchanger 12 can be switched. When the outdoor heat exchanger 12 is needed as a condenser, the flow regulating valve connecting the exhaust port of the compressor 11 to the outdoor heat exchanger 12 is opened, and the flow regulating valve connecting the outdoor heat exchanger 12 to the suction port of the compressor 11 is closed, allowing high-temperature exhaust gas to enter the outdoor heat exchanger 12 for condensation and heat release. When the outdoor heat exchanger 12 is needed as an evaporator, the flow regulating valve connecting the exhaust port of the compressor 11 to the outdoor heat exchanger 12 is closed, and the flow regulating valve connecting the outdoor heat exchanger 12 to the suction port of the compressor 11 is opened, allowing the refrigerant flowing back from the terminal equipment group 13 to evaporate and absorb heat in the outdoor heat exchanger 12 before flowing back to the suction port of the compressor 11. This achieves the refrigerant flow direction switching function of a traditional four-way valve, enabling the multi-split system to flexibly switch between different operating modes.

[0025] In this embodiment, the second reversing assembly 30 includes a third flow regulating valve 31 and a fourth flow regulating valve 32, which are connected in parallel. The two ends of the third flow regulating valve 31 are connected to the exhaust port of the compressor 11 and the outdoor heat exchanger 12, respectively. The two ends of the fourth flow regulating valve 32 are connected to the outdoor heat exchanger 12 and the suction port of the compressor 11, respectively. The third flow regulating valve 31 controls the refrigerant flow direction between the exhaust port of the compressor 11 and the outdoor heat exchanger 12. When the third flow regulating valve 31 is opened, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 11 can enter the outdoor heat exchanger 12 through this valve, allowing the outdoor heat exchanger 12 to function as a condenser. The fourth flow regulating valve 32 controls the refrigerant flow direction between the outdoor heat exchanger 12 and the suction port of the compressor 11. When the fourth flow regulating valve 32 is opened, the low-temperature, low-pressure gaseous refrigerant generated by the outdoor heat exchanger 12 as an evaporator can flow back to the compressor 11 through this valve. In this embodiment, the second reversing component 30 is specifically embodied as two parallel and clearly defined flow regulating valves. The independent valve body replaces the traditional integrated four-way valve, which not only reduces the cost of the multi-split system, but also reduces the volume occupied by the reversing mechanism, making the pipeline layout more compact and flexible.

[0026] In the above description, the third flow regulating valve 31 and the fourth flow regulating valve 32 in the second reversing assembly 30 are both electronic expansion valves. Similarly, due to the compact size and continuously adjustable opening of electronic expansion valves, by limiting the third flow regulating valve 31 and the fourth flow regulating valve 32 in the second reversing assembly 30 to electronic expansion valves, a compact structure is used to replace the traditional large-size four-way valve to complete the refrigerant flow path switching. This meets the design requirements of miniaturized layout for multi-split systems, while also providing refrigerant flow regulation and eliminating the mechanical impact noise generated by the four-way valve through pressure differential reversal.

[0027] In this embodiment, the refrigerant circuit 10 further includes an outdoor electronic expansion valve 14. Each terminal device in the terminal device group 13 is connected to the outdoor heat exchanger 12 sequentially through its corresponding on / off valve and the outdoor electronic expansion valve 14. The outdoor electronic expansion valve 14 connects the liquid side of the terminal device group 13 and the liquid side of the outdoor heat exchanger 12, and is used for throttling and depressurizing the refrigerant and finely regulating its flow. During operation of the multi-split system, the on / off valves of each terminal device in the terminal device group 13 are controlled according to their capacity requirements. For terminal devices with capacity requirements, their corresponding on / off valves are open, allowing refrigerant to flow through the terminal device for heat exchange and then exit from the liquid side; for terminal devices without capacity requirements, their corresponding on / off valves are closed, and refrigerant does not flow through the terminal device. The refrigerant flow rate from and to each terminal device is dynamically regulated by the outdoor electronic expansion valve 14. Thus, the multi-split system achieves a highly efficient refrigerant distribution architecture with decentralized on / off control and centralized throttling regulation. This embodiment separates decentralized on / off valves from centralized throttling by configuring independent on / off valves for each terminal device and centralizing the throttling function in a single outdoor electronic expansion valve 14. This structure reduces the manufacturing cost and complexity of the terminal devices, facilitates centralized maintenance of the throttling components, and ensures accurate matching of refrigerant flow and terminal load, thereby improving the economy and operating efficiency of the multi-split system.

[0028] In this embodiment, the refrigerant circuit 10 further includes an oil separator 15, a gas-liquid separator 16, and a subcooler 17. The refrigerant inlet of the oil separator 15 is connected to the exhaust port of the compressor 11, and the refrigerant outlet of the oil separator 15 is connected to the first reversing assembly 20 and the second reversing assembly 30, respectively. The refrigerant inlet of the gas-liquid separator 16 is connected to the first reversing assembly 20 and the second reversing assembly 30, respectively, and the refrigerant outlet of the gas-liquid separator 16 is connected to the suction port of the compressor 11. The subcooler 17 is installed on the refrigerant pipeline between the outdoor heat exchanger 12 and the terminal equipment group 13. The oil separator 15 separates lubricating oil from the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 11 and returns the separated lubricating oil to the compressor 11, ensuring sufficient lubrication of all moving parts of the compressor 11. Simultaneously, the pure gaseous refrigerant after removing the lubricating oil continues to flow to each reversing assembly, preventing oil film from adhering to the inner wall of the heat exchanger and reducing heat exchange efficiency. The gas-liquid separator 16 is used to separate the refrigerant into gas and liquid phases before it enters the compressor 11. Under sudden changes in operating conditions of the multi-split system, the return gas may contain incompletely evaporated liquid refrigerant. The gas-liquid separator 16 separates the liquid refrigerant into gas and liquid phases, allowing only gaseous refrigerant to enter the compressor 11, thereby effectively preventing liquid slugging accidents in the compressor 11 and protecting its safe operation. In this embodiment, by adding an oil separator 15 and a gas-liquid separator 16 to the refrigerant circuit 10, and by having the refrigerant outlet of the oil separator 15 connected to two reversing components in two separate paths, and the inlet of the gas-liquid separator 16 receiving return gas from the two reversing components in two separate paths, the separation and recovery of lubricating oil in the compressor 11's exhaust gas and the interception of liquid refrigerant in the suction gas are achieved. This effectively ensures reliable lubrication and liquid slugging prevention of the compressor 11, guaranteeing the long-term stability of the multi-split system. Furthermore, in this embodiment, the subcooler 17 is used to perform secondary cooling on the liquid refrigerant flowing out of the outdoor heat exchanger 12 and about to enter the terminal equipment group 13, further reducing its temperature below the saturation temperature, thereby increasing the subcooling of the refrigerant. The greater the subcooling, the more heat the refrigerant absorbs when evaporating in the terminal equipment, and the higher the energy efficiency ratio of the multi-split system. In this embodiment, by adding a subcooler 17 to the liquid-side refrigerant pipeline between the outdoor heat exchanger 12 and the terminal equipment group 13, the liquid refrigerant entering the terminal equipment group 13 is subjected to secondary cooling, which improves the subcooling of the refrigerant, thereby increasing the heat exchange capacity per unit of refrigerant and improving the heat exchange efficiency of the multi-split system.

[0029] Furthermore, multi-split systems can operate in multiple modes, including heating mode, cooling mode, heating and supplying heat mode, cooling and supplying heat mode, and defrosting mode. The heating and supplying heat mode can be understood as providing both heating and hot water / underfloor heating, while the cooling and supplying heat mode can be understood as providing both cooling and hot water / underfloor heating.

[0030] When the multi-split air conditioning system needs to switch to heating mode, the first flow regulating valve 21 and the fourth flow regulating valve 32 open, while the second flow regulating valve 22 and the third flow regulating valve 31 close. The refrigerant flow path is as follows: The compressor 11 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas. After the exhaust gas passes through the oil separator 15 to separate the lubricating oil, the high-temperature, high-pressure gas enters the indoor unit of the terminal equipment group 13 with heating requirements via the first flow regulating valve 21. The refrigerant condenses and releases heat in the indoor unit, becoming a medium-temperature, high-pressure liquid, which flows out from the liquid side of the indoor unit. The liquid refrigerant flows through the cooler 17 for further cooling before entering the outdoor electronic expansion valve 14. The outdoor electronic expansion valve 14 throttles and reduces the pressure of the liquid refrigerant, making it a low-temperature, low-pressure gas-liquid two-phase state, which then enters the outdoor heat exchanger 12. In the outdoor heat exchanger 12, the refrigerant evaporates and absorbs heat, becoming a low-temperature, low-pressure gas. Low-temperature, low-pressure gas enters the gas-liquid separator 16 through the fourth flow regulating valve 32, and gaseous refrigerant is drawn into the compressor 11 from the outlet of the gas-liquid separator 16, so that the multi-split system switches to heating mode.

[0031] When the multi-split system needs to switch to cooling mode, the first flow regulating valve 21 and the fourth flow regulating valve 32 are closed, while the second flow regulating valve 22 and the third flow regulating valve 31 are open. The refrigerant flow path is as follows: The compressor 11 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas. The exhaust gas passes through the oil separator 15 and enters the third flow regulating valve 31. The high-temperature, high-pressure gas then enters the outdoor heat exchanger 12 through the third flow regulating valve 31. The refrigerant condenses and releases heat in the outdoor heat exchanger 12, becoming a medium-temperature, high-pressure liquid. It flows out of the outdoor heat exchanger 12 and is further cooled by the cooler 17. The liquid refrigerant then enters the outdoor electronic expansion valve 14 for throttling and pressure reduction, becoming a low-temperature, low-pressure gas-liquid two-phase state. It is then distributed to the indoor units in the terminal equipment group 13 that have cooling needs. The refrigerant evaporates and absorbs heat in the indoor unit, becoming a low-temperature, low-pressure gas. It flows out from the gas side of the indoor unit, passes through the second flow regulating valve 22, and enters the gas-liquid separator 16. The gaseous refrigerant is then drawn into the compressor 11, allowing the multi-split system to switch to cooling mode.

[0032] When the multi-split system needs to switch to heating mode, the first flow regulating valve 21 and the fourth flow regulating valve 32 open, while the second flow regulating valve 22 and the third flow regulating valve 31 close. The refrigerant flow path is as follows: The compressor 11 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas. After the exhaust gas passes through the oil separator 15 to separate the lubricating oil, the high-temperature, high-pressure gas enters the indoor units, water heaters, and underfloor heating heat exchangers in the terminal equipment group 13 that require heating, via the first flow regulating valve 21. The refrigerant condenses and releases heat in the indoor units, water heaters, and underfloor heating heat exchangers, becoming a medium-temperature, high-pressure liquid. It flows out from the liquid side of the terminal equipment group 13. The liquid refrigerant is further cooled by the cooler 17 before entering the outdoor electronic expansion valve 14. The outdoor electronic expansion valve 14 throttles and reduces the pressure of the liquid refrigerant, making it a low-temperature, low-pressure gas-liquid two-phase state, which then enters the outdoor heat exchanger 12. In the outdoor heat exchanger 12, the refrigerant evaporates and absorbs heat, becoming a low-temperature, low-pressure gas. Low-temperature, low-pressure gas enters the gas-liquid separator 16 through the fourth flow regulating valve 32. Gaseous refrigerant is drawn into the compressor 11 from the outlet of the gas-liquid separator 16, so that the multi-split system switches to heating mode and operates in heating mode.

[0033] When the multi-split system needs to switch to cooling and heating mode, the first flow regulating valve 21 and the fourth flow regulating valve 32 are closed, and the second flow regulating valve 22 and the third flow regulating valve 31 are open. The refrigerant flow path is as follows: the compressor 11 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas. The exhaust from the compressor 11 is divided into two paths after passing through the oil separator 15. One path of high-temperature, high-pressure gaseous refrigerant enters the outdoor heat exchanger 12 through the third flow regulating valve 31 for condensation and heat release. The other path of high-temperature, high-pressure gaseous refrigerant is separately sent to the water heater and underfloor heating heat exchanger in the terminal equipment group 13 for condensation and heat release. The refrigerant flowing out from the outdoor heat exchanger 12, the water heater, and the underfloor heating heat exchanger is further cooled by the cooler 17. The liquid refrigerant then enters the outdoor electronic expansion valve 14 for throttling and pressure reduction, becoming a low-temperature, low-pressure gas-liquid two-phase state, and is then distributed to the indoor units in the terminal equipment group 13 that have cooling needs. The refrigerant evaporates and absorbs heat inside the indoor unit, becoming a low-temperature, low-pressure gas. It flows out from the gas side of the indoor unit and enters the gas-liquid separator 16 through the second flow regulating valve 22. The gaseous refrigerant is drawn into the compressor 11, so that the multi-split system switches to cooling and heating mode.

[0034] When the multi-split system needs to switch to defrost mode, the first flow regulating valve 21 and the fourth flow regulating valve 32 are open, and the second flow regulating valve 22 and the third flow regulating valve 31 are closed. The refrigerant flow path is as follows: After the compressor 11 discharges into the oil separator 15, it enters the low-pressure gas side of the terminal equipment group 13 through the first flow regulating valve 21, flows in reverse through the indoor unit, and enters the outdoor heat exchanger 12 through the fully open outdoor electronic expansion valve 14 to condense and release heat for defrosting. The defrosted liquid refrigerant flows back through the fourth flow regulating valve 32, and then returns to the compressor 11 through the gas-liquid separator 16, so that the multi-split system can switch to defrosting mode.

[0035] It should be noted that a solenoid valve is installed on the liquid-side pipe connected to the terminal equipment group 13, and a solenoid valve is installed on the gas-side pipe connected to the terminal equipment group 13. When the refrigerant needs to flow through the liquid side and the gas side, the corresponding solenoid valve is opened to allow the refrigerant to flow. When the refrigerant does not need to flow through the liquid side and the gas side, the corresponding solenoid valve is closed to prevent the refrigerant from flowing.

[0036] This embodiment provides a multi-split air conditioning system that replaces the traditional four-way valve switching mechanism used in multi-split air conditioning systems by setting a first reversing assembly and a second reversing assembly, which are composed of at least two parallel flow regulating valves. These components are respectively connected between the compressor exhaust port and the terminal equipment group, between the terminal equipment group and the compressor suction port, between the compressor exhaust port and the outdoor heat exchanger, and between the outdoor heat exchanger and the compressor suction port. By utilizing the compact structure and flexible layout of the flow regulating valve itself, the space occupied by the reversing assembly inside the outdoor unit is reduced, avoiding the problems of pipeline congestion and large unit size caused by using multiple large-size four-way valves. This allows the multi-split air conditioning system to achieve switching control of multiple working modes such as tri-generation within a limited space, meeting the design requirements of miniaturization and compactness of multi-split air conditioning systems.

[0037] refer to Figure 2 , Figure 2 This is a flowchart illustrating a control method for a multi-split air conditioner provided in an embodiment of this application. The control method for a multi-split air conditioner provided in this embodiment includes the following steps: S201: Obtain the operating mode that the multi-split air conditioning system needs to switch to, the outdoor ambient temperature of the outdoor environment where the multi-split air conditioning system is located, and the corresponding system pressure information of the multi-split air conditioning system.

[0038] In this embodiment, the solution is applied to the controller of a multi-split air conditioning system. The operating modes include heating mode, cooling mode, heating and supply mode, cooling and supply mode, and defrosting mode.

[0039] System pressure information includes system condensing pressure and system evaporating pressure. System condensing pressure refers to the pressure in the high-pressure line near the compressor's discharge port, and system evaporating pressure refers to the pressure in the low-pressure line near the compressor's suction port. Different system pressure information is selected as the basis for control under different operating modes.

[0040] Specifically, the operating mode that the current multi-split system needs to switch to can be obtained by reading the operating instructions set by the user (such as remote control signals or wired controller settings); the outdoor ambient temperature can be collected in real time by the temperature sensor installed on the outdoor unit of the multi-split system; and the system condensing pressure and system evaporating pressure can be obtained by the high-pressure sensor installed near the compressor exhaust port and the low-pressure sensor installed near the air intake port, respectively.

[0041] S202: Based on the operating mode, determine the target operating state of each flow regulating valve included in the first reversing assembly and the second reversing assembly.

[0042] In this embodiment, the target operating state includes an regulated state and a non-regulated state. The non-regulated state includes a fully open state and a fully closed state. The regulated state indicates that the valve opening of the flow control valve can be dynamically adjusted; the fully open state indicates that the valve of the flow control valve is opened to its maximum opening value, providing the maximum flow area; the fully closed state indicates that the valve of the flow control valve is opened to its minimum opening value, cutting off the refrigerant flow.

[0043] Specifically, the controller has a pre-stored lookup table between operating modes and the target operating states of each flow control valve. After obtaining the operating mode, the controller can use the lookup table to retrieve the target operating state of each flow control valve corresponding to that operating mode.

[0044] It should be noted that before executing step S202, the compressor in the multi-split system is controlled to reduce its frequency to a preset frequency threshold, and the opening of each flow regulating valve is controlled to be reduced to a preset opening threshold. Step S202 is executed when a preset time threshold has elapsed and the absolute difference between the system condensing pressure and the system evaporating pressure in the system pressure information is less than a preset difference threshold.

[0045] The aforementioned preset frequency threshold is the safe operating frequency of the compressor. The preset opening threshold can be set according to actual needs; a small flow rate of refrigerant can be pre-set to pass through the flow regulating valve. The preset duration threshold can be 10 seconds, which can be set according to actual needs. The preset difference threshold is a pre-set safe pressure difference between the high and low pressure sides. Through the above methods, this embodiment uses a split-type flow regulating valve to replace the traditional four-way valve architecture. This allows for a smooth pre-balancing of the high and low pressure sides of the system before mode switching, eliminating the risks of refrigerant shock and compressor liquid slugging during valve switching. This enables non-stop mode switching of the multi-split system and improves the operational reliability of the multi-split system.

[0046] S203: For each flow control valve whose target operating state is non-regulating, control the opening degree of the flow control valve based on the target operating state of the flow control valve; and for each flow control valve whose target operating state is regulating, control the opening degree of the flow control valve based on the operating mode, outdoor ambient temperature and system pressure information, so as to enable the multi-split system to switch to the operating mode.

[0047] In this embodiment, the controller sends a fully open command to each flow control valve whose target operating state is fully open, maintaining its maximum flow area; and sends a fully close command to each flow control valve whose target operating state is fully closed, completely shutting it off. During the operation of this working mode, the opening degree of these flow control valves whose target operating state is not in regulation remains unchanged unless a mode switch or protective action occurs.

[0048] For each flow control valve whose target operating state is regulation, the controller has pre-set control rules corresponding to each operating mode. These control rules use outdoor ambient temperature and system pressure information as input variables. When the multi-split system is operating, the controller reads the current operating mode, outdoor ambient temperature, and system pressure in real time. Based on the pre-set control rules, it calculates the target opening degree that the flow control valve should perform under the current operating conditions and drives the flow control valve to adjust to that opening position. As the multi-split system operates, changes in outdoor ambient temperature or fluctuations in system pressure occur, the controller continuously adjusts the target opening degree using updated parameter information. This allows the flow control valve opening to dynamically adapt to actual operating conditions, ensuring that the refrigerant distribution in the refrigerant circuit matches the current heat load demand of the multi-split system.

[0049] This embodiment provides a control method for a multi-split air conditioning system. For multi-split air conditioning systems without four-way valve switching, the method matches the target working state of each flow regulating valve with the working mode, and then controls the opening degree of each flow regulating valve in a graded manner according to the non-regulating state and the regulating state. Combined with outdoor ambient temperature and system pressure parameters, dynamic and precise adjustment is achieved. This not only ensures the reliability of switching between multiple working modes, but also meets the technical requirement of reducing the size of the multi-split air conditioning system.

[0050] refer to Figure 3 , Figure 3 This is a flowchart illustrating another control method for a multi-split air conditioning system provided in this embodiment. The control method for a multi-split air conditioning system provided in this embodiment specifically includes the following steps: S301: Obtain the operating mode that the multi-split air conditioning system needs to switch to, the outdoor ambient temperature of the outdoor environment where the multi-split air conditioning system is located, and the corresponding system pressure information of the multi-split air conditioning system.

[0051] In this embodiment, step S301 is the same as step S201 described above. For details, please refer to step S201 described above. This embodiment will not repeat the details here.

[0052] Before performing step S301, the control method for a multi-unit air conditioning system provided in this embodiment further includes the following steps: In response to the power-on signal of the multi-split air conditioning system, control all flow regulating valves in the first and second reversing assemblies to close completely; When the time for which each flow regulating valve is fully closed reaches the first preset time, control each flow regulating valve to the first preset opening degree; When each flow regulating valve operates at the first preset opening degree for a duration that reaches the second preset duration, the flow regulating valve is controlled to the second preset opening degree.

[0053] The power-on signal can be understood as the trigger signal received by the controller after the multi-split system is powered on, indicating that the multi-split system has started up. It is the only real indicator that the multi-split system has entered the working preparation state from the power-off standby state.

[0054] The first preset duration is the duration for which each flow regulating valve is kept fully closed, for example, 3 seconds. The purpose of setting this first preset duration is to ensure that each flow regulating valve has enough time to complete the closing action and stabilize in the fully closed state.

[0055] The first preset opening degree is the pre-set opening degree of each flow control valve, so as to drive each flow control valve to complete the large stroke action and solve the problem of jamming of each flow control valve after long-term power failure and static placement.

[0056] The second preset duration is a fixed time for which each flow regulating valve is pre-set to operate continuously at the first preset opening degree, in order to completely eliminate the risk of jamming. The second preset duration can be 10 seconds.

[0057] The second preset opening is a small standby opening of each flow regulating valve that is less than the first preset opening. It is the preparatory opening for the multi-split system to be powered on and in standby mode, so that all flow regulating valves are kept slightly open to slowly balance the pressure difference between the high and low pressure sides of the refrigerant circuit and avoid overload, start-up failure or even compressor damage when the compressor starts due to excessive pressure difference.

[0058] Specifically, after the controller detects a power-on signal, it sends a full-close command to all flow control valves in the first and second reversing assemblies. Upon receiving the command, each flow control valve performs a full-close action. When the full-close duration reaches a preset first preset duration, the controller sends a command to each flow control valve to open to a preset first preset opening degree. Upon receiving the command, each flow control valve performs an opening action and stops after reaching the preset first opening degree.

[0059] When the time taken to reach the first preset opening degree reaches the second preset time, the controller sends an instruction to each flow regulating valve to adjust to the second preset opening degree. After receiving the instruction, each flow regulating valve performs the opening adjustment action, stops after reaching the second preset opening degree, and executes the subsequent S301 step.

[0060] Through the above methods, this embodiment forces each flow regulating valve to sequentially close completely, open to the first preset opening degree, and then adjust to a smaller second preset opening degree after power-on. This achieves a unified reset of the reference position of each flow regulating valve, eliminates the initial position deviation caused by power failure, avoids refrigerant flow runaway or pressure shock during startup, and provides a reliable foundation for accurate control of the subsequent opening degree of the multi-split system.

[0061] S302: Based on the operating mode, determine the target operating state of each flow regulating valve included in the first reversing assembly and the second reversing assembly.

[0062] In this implementation, the comparison table between the working modes and the target working states of each flow control valve is shown in Table 1.

[0063] Table 1. Comparison of operating modes and target operating states of each flow control valve

[0064] Regarding Table 1 above, when the working mode is heating mode or heating and supply mode, the target working state of the first flow regulating valve in the first reversing assembly is the regulating state, the target working state of the second flow regulating valve in the first reversing assembly and the third flow regulating valve in the second reversing assembly is the fully closed state, and the target working state of the fourth flow regulating valve in the second reversing assembly is the fully open state. When the working mode is cooling mode, the target working state of the first flow regulating valve and the fourth flow regulating valve is fully closed, and the target working state of the second flow regulating valve and the third flow regulating valve is fully open. When the working mode is cooling and heating, the target working state of the first flow regulating valve and the fourth flow regulating valve is fully closed, the target working state of the second flow regulating valve is regulating, and the target working state of the third flow regulating valve is fully open. When the working mode is defrosting mode, the target working state of the first flow regulating valve and the fourth flow regulating valve is the regulating state, and the target working state of the second flow regulating valve and the third flow regulating valve is the fully closed state.

[0065] In the heating mode or heating mode and supply mode, the first flow regulating valve, as the main refrigerant supply route for the terminal equipment group, is set to the regulating state, which can adjust the amount of refrigerant supplied to the terminal equipment group according to the environment and load; the second flow regulating valve is fully closed, cutting off the refrigerant return gas branch of the terminal equipment group to prevent refrigerant crossflow; the third flow regulating valve is fully closed, cutting off the passage from the compressor exhaust to the outdoor heat exchanger to avoid ineffective loss of heating heat; the fourth flow regulating valve remains fully open to ensure smooth return of refrigerant after heat absorption by the outdoor heat exchanger and maintain stable operation of the heating cycle.

[0066] When the operating mode is cooling mode, the first flow regulating valve is fully closed, sealing off the pipeline supplying refrigerant to the terminal equipment group and isolating the heating circuit; the fourth flow regulating valve is fully closed, sealing off the return gas passage on the heating side to prevent high and low pressure cross-pressure; the third flow regulating valve is fully open, ensuring that the high-temperature exhaust gas from the compressor enters the outdoor heat exchanger to complete condensation and heat dissipation; the second flow regulating valve is fully open, connecting the indoor unit's refrigerant return gas passage, allowing the low-pressure refrigerant after heat absorption to flow back, maintaining stable operation of the refrigeration cycle.

[0067] When operating in both cooling and heating modes, the first and fourth flow regulating valves are kept fully closed to lock the cooling circuit and prevent interference from the heating branch; the third flow regulating valve is fully open to maintain normal condensation operation of the outdoor heat exchanger; the second flow regulating valve is set to the regulating state to dynamically match the flow of indoor refrigerant and prevent flow imbalance in the multi-split system.

[0068] When the working mode is defrosting mode, the second and third flow regulating valves are fully closed, shutting off the conventional refrigeration and heating working circuits to avoid interfering with the reverse defrosting cycle; the first flow regulating valve is set to the regulating state, which can controllably deliver high-temperature and high-pressure refrigerant from the compressor to achieve reverse heating and defrosting of the outdoor heat exchanger; the fourth flow regulating valve is set to the regulating state, which can dynamically match the refrigerant flow during the defrosting process.

[0069] Through the above methods, this embodiment presets the target working state combination of each flow regulating valve for different working modes, so that each flow regulating valve operates according to the corresponding target working state in a specific working mode. Thus, the distributed flow regulating valve group completely replaces the traditional four-way valve, and realizes reliable switching and stable operation of the multi-unit system under all working conditions in a compact structure.

[0070] S303: For each flow control valve whose target operating state is non-regulating, control the opening degree of the flow control valve based on the target operating state of the flow control valve.

[0071] In this embodiment, step S303 is the same as step S203 described above. For details, please refer to step S203 described above. This embodiment will not repeat the details here.

[0072] S304: For each flow control valve whose target operating state is the regulation state, based on the operating mode, outdoor ambient temperature and system pressure information, determine the first initial opening degree of the flow control valve and the first running time of the flow control valve operating at the initial opening degree.

[0073] S305: Controls the flow regulating valve to operate at the first initial opening.

[0074] S306: When the first running time is reached, determine the first target opening degree corresponding to the flow regulating valve based on the working mode and the first initial opening degree.

[0075] S307: Based on the first target opening degree, control the opening degree of the flow regulating valve to enable the multi-split system to switch to the working mode.

[0076] Regarding steps S304 to S307 above, the first initial opening can be understood as the initial opening set for the flow control valve in the target operating state of adjustment after the multi-split system enters a certain working mode, so that the multi-split system can start smoothly and avoid operational oscillations caused by improper opening.

[0077] The first running time refers to the preset duration for which the flow regulating valve continues to operate at the first initial opening degree, so as to reserve sufficient stabilization time for the refrigerant circulation in the multi-split system and ensure the accuracy of subsequent opening degree calculations.

[0078] The first target opening degree refers to the final opening degree value of the flow control valve in steady-state operation, determined based on the current working mode and the first initial opening degree, after the first initial opening degree running time has reached the first running time.

[0079] Specifically, the controller has a pre-set lookup table that corresponds to the initial opening degree and the initial running time for each operating mode, outdoor ambient temperature, and system pressure information. When the operating mode, outdoor ambient temperature, and system pressure information are determined, the lookup table is queried using the above parameters as input to obtain the corresponding initial opening degree and initial running time.

[0080] An opening command is sent to the flow control valve, which includes a first initial opening and a first operating duration. The flow control valve adjusts its opening based on the command and maintains the first initial opening. During operation, if the operating duration reaches the first operating duration, a first target opening is determined according to a preset algorithm or rule based on the current operating mode and the first initial opening value.

[0081] The calculated first target opening is converted into a corresponding control command and sent to the flow control valve. The flow control valve adjusts its opening based on the received control command. After the flow control valve is adjusted to the first target opening, the first target opening is updated within a preset adjustment period based on the operating mode and the first target opening to complete the closed-loop adjustment of the flow control valve.

[0082] In this embodiment, the initial opening of the flow control valve is determined based on the working mode, outdoor ambient temperature, and system pressure information, and the valve is run for a first running time. After the first running time is reached, the target opening is determined based on the working mode and the initial opening, and the opening is adjusted. This avoids the operational oscillations caused by blindly adjusting the flow control valve due to drastic pressure and temperature fluctuations during the initial startup of the multi-split system. This allows the refrigerant circuit to establish a stable operating state under controlled conditions, ensuring smooth switching and stable operation of the multi-split system between different working modes.

[0083] In this embodiment, the system pressure information includes the system condensing pressure and the system evaporating pressure; the determination of the first initial opening degree of the flow regulating valve based on the operating mode, outdoor ambient temperature, and system pressure information in step S304 above includes: When the working mode is heating mode or heating and supply mode, the first initial opening degree of the flow regulating valve is determined based on the first temperature range of the outdoor ambient temperature and the first pressure range of the system evaporation pressure. When the operating mode is cooling mode, defrosting mode, or cooling and heating mode, the first initial opening degree of the flow regulating valve is determined based on the second temperature range of the outdoor ambient temperature and the second pressure range of the system condensing pressure.

[0084] The first temperature range refers to the temperature segment range of the outdoor ambient temperature in heating mode or heating and supply mode. The controller internally divides multiple continuous temperature ranges in heating mode or heating and supply mode, and different temperature ranges correspond to different determinations of the first initial opening degree.

[0085] The second temperature range refers to the temperature segment range of the outdoor temperature in cooling mode, cooling and heating mode, or defrost mode. The controller internally divides multiple continuous temperature ranges in cooling mode, cooling and heating mode, or defrost mode, and different temperature ranges correspond to different determinations of the first initial opening degree.

[0086] The first pressure range refers to the pressure segment range of the system evaporation pressure in heating mode or heating and supply mode. The controller internally divides the system into multiple continuous pressure ranges in heating mode or heating and supply mode, and different pressure ranges correspond to different determinations of the first initial opening degree.

[0087] The second pressure range refers to the pressure segment range of the system condensing pressure in cooling mode, cooling and heating mode, or defrosting mode. The controller internally divides multiple continuous pressure ranges in cooling mode, cooling and heating mode, or defrosting mode, and different pressure ranges correspond to different determinations of the first initial opening degree.

[0088] Specifically, the first initial opening degree increases with the increase of the first temperature range and the first pressure range, and decreases with the increase of the second temperature range and the second pressure range. In heating mode or heating and supply mode, the higher the temperature and pressure, the greater the refrigerant circulation flow gap, so the refrigerant supply is increased to ensure heat exchange efficiency; in cooling mode, cooling and supply mode, or defrosting mode, the higher the temperature and pressure, the more difficult the heat exchange, so the refrigerant supply is reduced.

[0089] The controller has a pre-set lookup table for the initial opening degree corresponding to each operating mode, temperature range, and pressure range, as shown in Table 2. After obtaining the operating mode, first temperature range, and first pressure range, the above parameters can be used as input to look up the lookup table to obtain the initial opening degree of the flow control valve in heating mode or heating and supply mode. Similarly, after obtaining the operating mode, second temperature range, and second pressure range, the above parameters can be used as input to look up the lookup table to obtain the initial opening degree of the flow control valve in cooling mode, cooling and supply mode, or defrosting mode.

[0090] Table 2. Comparison of the initial opening degree for each operating mode, temperature range, and pressure range.

[0091] By using the above methods, this embodiment sets the first initial opening degree of each flow regulating valve differently according to different working modes, outdoor ambient temperature ranges, and system pressure ranges. This ensures that the first initial opening degree of each flow regulating valve is accurately matched with the actual operating conditions, avoids the problem of refrigerant flow ratio imbalance, and guarantees the operational stability of the multi-split system.

[0092] In this embodiment, step S306 specifically includes: When the working mode is heating mode or heating and supply mode, determine the average subcooling degree among all indoor units that have been turned on in the terminal equipment group, and determine the first target opening degree corresponding to the first flow regulating valve based on the average subcooling degree and the first initial opening degree. When the working mode is cooling and heating, determine the subcooling degree corresponding to the water heater or floor heating heat exchanger that has been turned on in the terminal equipment group, and determine the first target opening degree corresponding to the second flow regulating valve based on the subcooling degree and the first initial opening degree. When the working mode is defrosting mode, the temperature of the first coil and the superheat of the compressor are determined. Based on the temperature of the first coil and the first initial opening, the first target opening of the first flow regulating valve is determined. Based on the superheat and the first initial opening, the first target opening of the fourth flow regulating valve is determined.

[0093] The average subcooling can be understood as the arithmetic mean of the subcooling of all indoor units that have been turned on in the terminal equipment group under heating mode or cooling and heating mode. The subcooling of the indoor unit can be determined as follows: determine the sum of the refrigerant inlet temperatures of all indoor units that have been turned on to obtain the first total temperature; determine the first saturation temperature corresponding to the system condensing pressure of the current multi-split system and the first number of all indoor units that have been turned on; then the average subcooling is equal to (first saturation temperature - first total temperature) / first number.

[0094] The first coil temperature is the maximum value among the coil temperatures of all the indoor units that have been turned on in the terminal equipment group. The maximum value is chosen to protect user comfort under the worst-case scenario and prevent any indoor unit from blowing out hot air due to excessive coil temperature.

[0095] In the heating mode or heating and supply mode, the average subcooling among all the indoor units that are turned on in the terminal equipment group (ensuring that all indoor units that need to be turned on can work normally) is determined, and a preset first target subcooling is determined (which is a function of the operating mode, outdoor ambient temperature, the average temperature among all indoor ambient temperatures, system evaporation pressure, compressor discharge temperature, and system condensation pressure). The first initial opening, average subcooling, and first target subcooling are input into the first formula to obtain the first target opening. The first formula includes: the first target opening equals the first initial opening + K3 × (average subcooling - first target subcooling). After obtaining the first target opening, the opening of the first flow regulating valve can be maintained at the first target opening using a PID algorithm. K3 is a variable proportional coefficient, which is adjusted by the indoor unit capacity, indoor unit fan speed, indoor ambient temperature, and indoor unit inlet pipe temperature, and can be understood as a piecewise proportional function.

[0096] It should be noted that after obtaining the first target opening degree, if the preset cycle is reached, the average subcooling degree and the first target subcooling degree can be determined, the first target opening degree obtained in the previous cycle can be updated to the first initial opening degree, and the newly determined average subcooling degree and the first target subcooling degree can be substituted into the first formula mentioned above to complete the update of the first target opening degree, thereby ensuring the stable operation of the multi-split system.

[0097] When the operating mode is both cooling and heating, the subcooling degree corresponding to the activated water heater or underfloor heating heat exchanger is determined, as well as the preset second target subcooling degree (which is also a function relating the operating mode, outdoor ambient temperature, the average temperature among all indoor ambient temperatures, system evaporation pressure, compressor discharge temperature, and system condensation pressure). The first initial opening degree, subcooling degree, and second target subcooling degree are input into the second formula to obtain the first target opening degree. The second formula includes: the first target opening degree equals the first initial opening degree + K2 × (subcooling degree - second target subcooling degree). After obtaining the first target opening degree, the opening degree of the second flow regulating valve can be maintained at the first target opening degree using a PID algorithm. K2 is a variable proportional coefficient, which is also affected by the indoor unit capacity, indoor unit fan speed, indoor ambient temperature, and indoor unit inlet pipe temperature, and can be understood as a piecewise proportional function.

[0098] It should be noted that after obtaining the first target opening degree, if the preset cycle is reached, the subcooling degree and the second target subcooling degree can be determined. The first target opening degree obtained in the previous cycle is updated to the first initial opening degree, and the newly determined subcooling degree and the second target subcooling degree are substituted into the first formula mentioned above to complete the update of the first target opening degree, thereby ensuring the stable operation of the multi-split system.

[0099] When the operating mode is defrosting mode, for the first flow regulating valve, the coil temperatures of all turned-on indoor units in the terminal equipment group are collected, and the maximum value is selected as the first coil temperature and the preset coil temperature is determined. The first initial opening, the first coil temperature, and the preset coil temperature are input into the third formula to obtain the first target opening. The third formula includes: the first target opening equals the first initial opening + K5 × (preset coil temperature - first coil temperature). After obtaining the first target opening, the opening of the first flow regulating valve can be maintained at the first target opening using a PID algorithm, where K5 is the proportional coefficient.

[0100] For the fourth flow control valve, determine the superheat corresponding to the compressor and the first target superheat. Input the first initial opening, superheat, and first target superheat into the fourth formula to obtain the first target opening. The fourth formula includes: the first target opening equals the first initial opening + K6 × (superheat - first target superheat). After obtaining the first target opening, a PID algorithm can be used to maintain the opening of the fourth flow control valve at the first target opening, where K6 is the proportional coefficient.

[0101] It should be noted that after obtaining the first target opening degree, if the preset cycle is reached, the first coil temperature and superheat can be determined, the first target opening degree obtained in the previous cycle can be updated to the first initial opening degree, and the newly determined subcooling degree and the second target subcooling degree can be substituted into the third and fourth formulas mentioned above to complete the update of the first target opening degree, thereby ensuring the stable operation of the multi-split system.

[0102] In this embodiment, by adjusting the opening degree of the flow regulating valves under different operating modes according to different control objectives, the opening degree of each flow regulating valve is dynamically matched with the heat exchange requirements of the multi-split air conditioning system, thereby improving the reliability of the multi-split air conditioning system.

[0103] In this embodiment, while controlling the opening degree of each flow regulating valve, the control method for a multi-split air conditioning system provided in this embodiment also includes the following steps: Based on the operating mode, outdoor ambient temperature, and system pressure information, determine the second initial opening degree of the outdoor electronic expansion valve and the second operating time of the outdoor electronic expansion valve operating at the second initial opening degree. Control the outdoor electronic expansion valve to operate at the second initial opening; When the second running time is reached, if the working mode is heating mode or heating mode and supply mode, the second target opening of the outdoor electronic expansion valve is determined based on the second coil temperature of the outdoor heat exchanger, the system pressure information and the second initial opening. If the working mode is cooling mode or cooling and heating mode, determine the average superheat among all indoor units that have been turned on in the terminal equipment group, and determine the second target opening of the outdoor electronic expansion valve based on the average superheat and the second initial opening. If the working mode is defrosting mode, the second target opening degree corresponding to the outdoor electronic expansion valve is set to fully open; The opening degree of the outdoor electronic expansion valve is controlled based on the second target opening degree.

[0104] The second initial opening is the initial opening value set for the outdoor electronic expansion valve after the multi-split system enters a certain operating mode. This provides a preset reference position for the outdoor electronic expansion valve, allowing the refrigerant circulation of the multi-split system to be established smoothly. The second running time refers to the preset length of time for the outdoor electronic expansion valve to continuously operate at the second initial opening, providing a transition buffer period for the multi-split system. It should be noted that the second initial opening and the second running time can also be preset using a lookup table as shown in Table 2, allowing the corresponding second initial opening and second running time to be determined by consulting the lookup table.

[0105] Average superheat refers to the arithmetic mean of the superheat of all the indoor units that are turned on in the terminal equipment group (it is necessary to ensure that all the indoor units that are turned on can operate normally) in cooling mode or cooling and heating mode.

[0106] Specifically, upon reaching the second operating time, if the operating mode is heating mode or both heating and supplying heat, the outdoor heat exchanger operates as an evaporator. The temperature of the second coil of the outdoor heat exchanger, as well as the current system pressure information (referring to the system evaporation pressure), are collected. The saturation temperature corresponding to the system evaporation pressure and the target superheat of the suction gas are determined. The second coil temperature, the saturation temperature corresponding to the system evaporation pressure, and the target superheat of the suction gas are input into the fifth formula to obtain the second target opening degree. The fifth formula includes: the second target opening degree equals the second initial opening degree + K4 × (second coil temperature - saturation temperature corresponding to the system evaporation pressure - target superheat of the suction gas). K4 is a proportionality coefficient, and K4 and the target superheat of the suction gas are preset. The target superheat of the suction gas is the preset superheat of the compressor suction gas.

[0107] When the second operating time is reached, if the operating mode is cooling mode or cooling and heating mode, the indoor unit operates as an evaporator. The sum of the refrigerant inlet temperatures of all activated indoor units is determined to obtain the second total temperature. The sum of the refrigerant outlet temperatures of all activated indoor units is determined to obtain the third total temperature. The second number of activated indoor units is determined, and the average superheat is equal to (third total temperature - second total temperature) / second number.

[0108] After obtaining the average superheat, a preset second target superheat is determined (which is a functional relationship with respect to the operating mode, outdoor ambient temperature, the average temperature among all indoor ambient temperatures, system evaporation pressure, compressor discharge temperature, and system condensation pressure). The second initial opening, average superheat, and second target superheat are input into the sixth formula to obtain the second target opening. The sixth formula includes: the second target opening equals the first initial opening + K1 × (average superheat - first target superheat). After obtaining the second target opening, a PID algorithm can be used to maintain the opening of the second flow control valve at the first target opening. K1 is a variable proportional coefficient, adjusted by the indoor unit capacity, indoor unit fan speed, indoor ambient temperature, and indoor unit inlet pipe temperature; it can be understood as a piecewise proportional function.

[0109] After reaching the second operating time, if the operating mode is defrosting, the outdoor heat exchanger operates as a condenser, and the refrigerant needs to flow back into the outdoor heat exchanger through the terminal equipment group. In this mode, the outdoor electronic expansion valve does not need to throttle; it should provide maximum flow area to reduce flow resistance and ensure smooth passage of the high-temperature exhaust required for defrosting. Therefore, the second target opening is directly set to fully open.

[0110] It should be noted that after obtaining the second target opening degree, if the preset cycle is reached, the corresponding variable parameters can be determined to update the second target opening degree obtained in the previous cycle to the second initial opening degree. The newly determined variable parameters are then substituted into the formula corresponding to the working mode to complete the update of the second target opening degree, thereby ensuring the stable operation of the multi-connected system.

[0111] Through the above methods, this embodiment sets up a phased control process for the outdoor electronic expansion valve. First, when the multi-split system starts up, it assigns a second initial opening degree based on the working mode, outdoor ambient temperature, and system pressure information, and maintains it for a second running time to initially stabilize the multi-split system. Then, based on the control objectives of the outdoor electronic expansion valve corresponding to each working mode, the opening degree of the outdoor electronic expansion valve is dynamically adjusted to achieve accurate matching of refrigerant flow under different operating conditions. This not only ensures the smoothness of the multi-split system startup but also improves the reliability of the multi-split system under all operating conditions.

[0112] This embodiment provides a control method for a multi-split air conditioning system. For multi-split air conditioning systems without four-way valve switching, the method matches the target working state of each flow regulating valve with the working mode, and then controls the opening degree of each flow regulating valve in a graded manner according to the non-regulating state and the regulating state. Combined with outdoor ambient temperature and system pressure parameters, dynamic and precise adjustment is achieved. This not only ensures the reliability of switching between multiple working modes, but also meets the technical requirement of reducing the size of the multi-split air conditioning system.

[0113] like Figure 4 As shown in the figure, this application embodiment provides another multi-unit system, including a processor 111, a communication interface 112, a memory 113, and a communication bus 114, wherein the processor 111, the communication interface 112, and the memory 113 communicate with each other through the communication bus 114. Memory 113 is used to store computer programs; In one embodiment of this application, the processor 111, when executing the program stored in the memory 113, implements the control method of the multi-unit system provided in any of the foregoing method embodiments.

[0114] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the control method for a multi-unit system as provided in any of the foregoing method embodiments.

[0115] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0116] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0117] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-split air conditioning system, characterized in that, include: Refrigerant circuit, first commutation assembly, and second commutation assembly; The refrigerant circuit includes a compressor, an outdoor heat exchanger, and a terminal equipment group; The first reversing assembly includes at least two flow regulating valves arranged in parallel, at least one of the flow regulating valves being connected to the discharge port of the compressor and the terminal equipment group, and at least one of the flow regulating valves being connected to the terminal equipment group and the suction port of the compressor; The second reversing assembly includes at least two flow regulating valves arranged in parallel, at least one of the flow regulating valves is connected to the exhaust port of the compressor and the outdoor heat exchanger, and at least one of the flow regulating valves is connected to the outdoor heat exchanger and the intake port of the compressor. The outdoor heat exchanger is connected to the terminal equipment group; By controlling each of the aforementioned flow regulating valves, the flow direction of the refrigerant in the refrigerant circuit is adjusted to switch the operating mode of the multi-split system.

2. The multi-unit air conditioning system according to claim 1, characterized in that, The first reversing assembly includes a first flow regulating valve and a second flow regulating valve, which are connected in parallel. The first flow regulating valve is connected at both ends to the exhaust port of the compressor and the terminal equipment group, respectively, and the second flow regulating valve is connected at both ends to the terminal equipment group and the intake port of the compressor, respectively.

3. The multi-unit air conditioning system according to claim 1, characterized in that, The second reversing assembly includes a third flow regulating valve and a fourth flow regulating valve, which are connected in parallel. The two ends of the third flow regulating valve are respectively connected to the exhaust port of the compressor and the outdoor heat exchanger, and the two ends of the fourth flow regulating valve are respectively connected to the outdoor heat exchanger and the intake port of the compressor.

4. The multi-unit air conditioning system according to any one of claims 1 to 3, characterized in that, The flow regulating valves in both the first and second reversing assemblies are electronic expansion valves.

5. The multi-unit air conditioning system according to claim 1, characterized in that, The terminal equipment group includes multiple terminal equipment arranged in parallel, and each terminal equipment is connected to the outdoor heat exchanger through an on / off valve.

6. The multi-unit air conditioning system according to claim 5, characterized in that, The refrigerant circuit also includes an outdoor electronic expansion valve; Each of the terminal devices in the terminal device group is connected to the outdoor heat exchanger in sequence through its corresponding on / off valve and outdoor electronic expansion valve.

7. The multi-unit air conditioning system according to claim 5, characterized in that, All of the aforementioned on / off valves are solenoid valves.

8. The multi-unit air conditioning system according to claim 5, characterized in that, The terminal equipment includes an indoor unit, a water heater, and a floor heating heat exchanger; At least one of the flow regulating valves in the first reversing assembly is connected to the exhaust port of the compressor and the indoor unit, the water heater, and the floor heating heat exchanger in the terminal equipment group; At least one of the flow regulating valves in the first reversing assembly is connected to the air intake of the indoor unit in the terminal equipment group and the compressor.

9. The multi-unit air conditioning system according to claim 1, characterized in that, The refrigerant circuit also includes an oil separator and a gas-liquid separator; The refrigerant inlet of the oil separator is connected to the exhaust port of the compressor, and the refrigerant outlet of the oil separator is connected to the first reversing assembly and the second reversing assembly respectively. The refrigerant inlet of the gas-liquid separator is connected to the first reversing assembly and the second reversing assembly, respectively, and the refrigerant outlet of the gas-liquid separator is connected to the suction port of the compressor.

10. The multi-unit air conditioning system according to claim 9, characterized in that, The refrigerant circuit also includes a subcooler; The subcooler is installed on the refrigerant pipeline between the outdoor heat exchanger and the terminal equipment group.

11. A control method for a multi-unit air conditioning system, characterized in that, Applied to a multi-split air conditioning system as described in any one of claims 1 to 10, the method comprises: The system obtains the operating mode that the multi-split air conditioning system needs to switch to, the outdoor ambient temperature of the outdoor environment where the multi-split air conditioning system is located, and the system pressure information corresponding to the multi-split air conditioning system. Based on the operating mode, the target operating state of each flow regulating valve included in the first reversing assembly and the second reversing assembly is determined. For each flow control valve whose target operating state is non-adjustment state, the opening degree of the flow control valve is controlled based on the target operating state of the flow control valve. For each flow control valve whose target operating state is adjustment state, the opening degree of the flow control valve is controlled based on the operating mode, the outdoor ambient temperature, and the system pressure information, so that the multi-split system switches to the operating mode.

12. The method according to claim 11, characterized in that, The method of controlling the opening degree of the flow regulating valve based on the operating mode, the outdoor ambient temperature, and the system pressure information includes: Based on the operating mode, the outdoor ambient temperature, and the system pressure information, determine the first initial opening degree of the flow regulating valve and the first operating time of the flow regulating valve at the initial opening degree; The flow regulating valve is controlled to operate at the first initial opening. When the first running time is reached, the first target opening degree corresponding to the flow regulating valve is determined based on the working mode and the first initial opening degree; Based on the first target opening degree, the opening degree of the flow regulating valve is controlled.

13. The method according to claim 12, characterized in that, The system pressure information includes system condensing pressure and system evaporating pressure; determining the first initial opening degree of the flow regulating valve based on the operating mode, the outdoor ambient temperature, and the system pressure information includes: When the working mode is heating mode or heating and supply mode, the first initial opening degree of the flow regulating valve is determined based on the first temperature range to which the outdoor ambient temperature belongs and the first pressure range to which the system evaporation pressure belongs. When the operating mode is cooling mode, defrosting mode, or cooling and heating mode, the first initial opening degree of the flow regulating valve is determined based on the second temperature range to which the outdoor ambient temperature belongs and the second pressure range corresponding to the system condensing pressure.

14. The method according to claim 12, characterized in that, When the working mode is heating mode or heating and supply mode, the target working state of the first flow regulating valve in the first reversing assembly is the regulating state, the target working state of the second flow regulating valve in the first reversing assembly and the third flow regulating valve in the second reversing assembly is the fully closed state, and the target working state of the fourth flow regulating valve in the second reversing assembly is the fully open state. When the operating mode is cooling mode, the target operating state of the first flow regulating valve and the fourth flow regulating valve is fully closed, and the target operating state of the second flow regulating valve and the third flow regulating valve is fully open. When the operating mode is cooling and heating mode, the target operating state of the first flow regulating valve and the fourth flow regulating valve is fully closed, the target operating state of the second flow regulating valve is the regulating state, and the target operating state of the third flow regulating valve is fully open. When the operating mode is defrosting mode, the target operating state of the first flow regulating valve and the fourth flow regulating valve is the regulating state, and the target operating state of the second flow regulating valve and the third flow regulating valve is the fully closed state.

15. The method according to claim 14, characterized in that, Determining the first target opening of the flow regulating valve based on the operating mode and the first initial opening includes: When the working mode is heating mode or heating and supply mode, the average subcooling degree among all indoor units that have been turned on in the terminal equipment group is determined, and based on the average subcooling degree and the first initial opening degree, the first target opening degree corresponding to the first flow regulating valve is determined. When the working mode is cooling and heating mode, the subcooling degree corresponding to the water heater or floor heating heat exchanger that has been turned on in the terminal equipment group is determined, and based on the subcooling degree and the first initial opening degree, the first target opening degree corresponding to the second flow regulating valve is determined. When the working mode is defrosting mode, the first coil temperature and the superheat corresponding to the compressor are determined. Based on the first coil temperature and the first initial opening, the first target opening corresponding to the first flow regulating valve is determined. Based on the superheat and the first initial opening, the first target opening corresponding to the fourth flow regulating valve is determined. The first coil temperature is the maximum value among the coil temperatures of all indoor units that have been turned on in the terminal equipment group.

16. The method according to claim 11, characterized in that, While controlling the opening degree of each of the aforementioned flow regulating valves, the method further includes: Based on the operating mode, the outdoor ambient temperature, and the system pressure information, determine the second initial opening degree of the outdoor electronic expansion valve and the second operating time of the outdoor electronic expansion valve operating at the second initial opening degree. The outdoor electronic expansion valve is controlled to operate at the second initial opening. When the second running time is reached, if the working mode is heating mode or heating and supply mode, the second target opening degree corresponding to the outdoor electronic expansion valve is determined based on the second coil temperature of the outdoor heat exchanger, the system pressure information and the second initial opening degree. If the working mode is cooling mode or cooling and heating mode, determine the average superheat among all indoor units that have been turned on in the terminal equipment group, and determine the second target opening of the outdoor electronic expansion valve based on the average superheat and the second initial opening. If the working mode is defrosting mode, the second target opening degree corresponding to the outdoor electronic expansion valve is determined to be fully open; Based on the second target opening degree, the opening degree of the outdoor electronic expansion valve is controlled.

17. The method according to claim 11, characterized in that, Before performing the step of obtaining the required operating mode for the multi-unit system, the method further includes: In response to the power-on signal of the multi-split air conditioning system, control each of the flow regulating valves in the first reversing assembly and the second reversing assembly to be fully closed; When the fully closed duration of each of the flow regulating valves reaches the first preset duration, control each of the flow regulating valves to the first preset opening degree; When each of the flow regulating valves operates at the first preset opening for a duration that reaches the second preset duration, the flow regulating valves are controlled to the second preset opening, where the second preset opening is less than the first preset opening.

18. A multi-split air conditioning system, comprising: A processor and a memory, the processor being configured to execute a control program for a multi-unit system stored in the memory to implement the control method for the multi-unit system according to any one of claims 11 to 17.

19. A storage medium, characterized in that, The storage medium stores one or more programs, which can be executed by one or more processors to implement the control method of the multi-unit system according to any one of claims 11 to 17.

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