Refrigeration control method and device of multi-split air conditioning system and electronic equipment

Abstract

The embodiment of the invention provides a refrigeration control method and device of a multi-split air conditioning system, electronic equipment and a computer readable storage medium, and relates to the field of air conditioners. The method comprises the steps that under the heating working condition, the environment temperature and the outlet pipe temperature of each air conditioner indoor unit in the current period are collected; and according to the environment temperature and the outlet pipe temperature of each air conditioner indoor unit in the current period, whether liquid accumulation exists in each air conditioner indoor unit in the current period or not is judged. According to the embodiment of the invention, the air conditioning unit can still operate safely when refrigerating at the high temperature of 60 DEG C or above, and the air conditioner has better capacity output in a high-temperature refrigerating environment.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and more specifically, to a refrigeration control method, apparatus, electronic device, computer-readable storage medium, and computer program product for a multi-split air conditioning system. Background Technology

[0002] In existing multi-split air conditioning systems, the expansion valve of the indoor unit typically adjusts its opening based on superheat. However, under extreme ambient temperatures, if the conventional superheat control strategy is still used, the compressor's extremely low operating frequency and small refrigerant flow rate can easily lead to insufficient valve opening, resulting in excessively high pressure or excessive exhaust temperature.

[0003] Therefore, under extreme high-temperature conditions, the system typically switches to a fixed-opening control mode based on high pressure or exhaust temperature. However, this strategy struggles to balance system reliability and cooling performance. Summary of the Invention

[0004] This application provides a refrigeration control method, apparatus, electronic device, computer-readable storage medium, and computer program product for a multi-split air conditioning system, which can solve the above-mentioned problems of the prior art. The technical solution is as follows: According to one aspect of the embodiments of this application, a refrigeration control method for a multi-split air conditioning system is provided. The multi-split air conditioning system includes an outdoor unit and multiple indoor units, each indoor unit including an indoor unit expansion valve. The method includes: Under the cooling condition where the outdoor unit ambient temperature is greater than or equal to the first temperature threshold, the opening degree of each indoor unit expansion valve in the current cycle, the compressor parameters of the outdoor unit in the current cycle, and the relationship between the average pipe temperature and the average indoor unit ambient temperature of the multiple indoor units in the current cycle are obtained. The opening degree of each indoor unit expansion valve in the next cycle is determined based on the opening degree of each indoor unit expansion valve in the current cycle, the ambient temperature of the outdoor unit, the compressor parameters, and the magnitude relationship.

[0005] According to another aspect of the embodiments of this application, a refrigeration control device for a multi-split air conditioning system is provided. The multi-split air conditioning system includes multiple indoor air conditioning units, and the device includes: The parameter acquisition module is used to acquire the opening degree of each indoor unit expansion valve in the current cycle, the compressor parameters of the outdoor unit in the current cycle, and the relationship between the average pipe temperature and the average indoor unit ambient temperature of the multiple indoor units in the current cycle when the outdoor unit ambient temperature is greater than or equal to the first temperature threshold. The opening degree determination module is used to determine the opening degree of each indoor unit expansion valve in the next cycle based on the opening degree of each indoor unit expansion valve in the current cycle, the ambient temperature of the outdoor unit, the compressor parameters, and the magnitude relationship.

[0006] According to another aspect of the present application, an electronic device is provided, which includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the above-described cooling control method for a multi-split air conditioning system.

[0007] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the above-described cooling control method for a multi-split air conditioning system.

[0008] According to one aspect of the embodiments of this application, a computer program product is provided, including a computer program that, when executed by a processor, implements the above-described cooling control method for a multi-split air conditioning system.

[0009] The beneficial effects of the technical solutions provided in this application are: By comprehensively considering the opening degree of the indoor unit expansion valve in the current cycle, the outdoor unit ambient temperature, the compressor parameters, and the relationship between the average pipe temperature and the average indoor unit ambient temperature, the current load of the system can be judged more accurately. Based on the linkage adjustment of the indoor unit expansion valve opening degree, pipe temperature, ambient temperature, compressor parameters, and outdoor unit ambient temperature, a closed-loop control can be formed to avoid system oscillation caused by single parameter adjustment. This helps to maintain the stable operation of the evaporator and improve the system's refrigeration efficiency and energy efficiency ratio. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below.

[0011] Figure 1 This is a schematic diagram of the structure of a multi-split air conditioning system provided in an embodiment of this application; Figure 2 A schematic flowchart illustrating a refrigeration control method for a multi-split air conditioning system provided in this application embodiment; Figure 3 A schematic flowchart illustrating a refrigeration control method for a multi-split air conditioning system provided in this application embodiment; Figure 4 A schematic diagram of the structure of a refrigeration control device for a multi-split air conditioning system provided in this application embodiment; Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0012] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions of the embodiments of this application.

[0013] Those skilled in the art will understand that, unless otherwise stated, the singular forms “a,” “an,” and “the” used herein may also include the plural forms. It should be further understood that the terms “comprising” and “including” as used in embodiments of this application mean that the corresponding feature can be implemented as the presented feature, information, data, step, operation, element, and / or component, but do not exclude implementation as other features, information, data, step, operation, element, component, and / or combinations thereof supported by the art. It should be understood that when we say that an element is “connected” or “coupled” to another element, the one element can be directly connected or coupled to the other element, or it can mean that the one element and the other element establish a connection relationship through an intermediate element. Furthermore, “connected” or “coupled” as used herein can include wireless connection or wireless coupling. The term “and / or” as used herein indicates at least one of the items defined by the term; for example, “A and / or B” can be implemented as “A,” or as “B,” or as “A and B.”

[0014] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0015] First, let's introduce and explain several terms used in this application: Subcooling refers to the temperature of a liquid refrigerant being lower than its saturation temperature (the temperature at which the refrigerant begins to change from a liquid to a gaseous state under that pressure, also known as the condensation temperature). For example, at the condenser outlet, the refrigerant is in a liquid state. If its actual temperature is 35°C, and the corresponding saturation temperature at that pressure is 40°C, then the subcooling is 40-35=5°C.

[0016] Superheat refers to the temperature of a gaseous refrigerant that is higher than its saturation temperature (the temperature at which the refrigerant begins to change from a gaseous state to a liquid state under that pressure, also known as the evaporation temperature). For example, at the evaporator outlet, the refrigerant is in a gaseous state. If its actual temperature is 10°C, and the corresponding saturation temperature at that pressure is 5°C, then the superheat is 10 - 5 = 5°C.

[0017] Please see Figure 1The figure illustrates a schematic diagram of a multi-split air conditioning system. As shown in the figure, the multi-split air conditioning system includes an outdoor unit and n indoor units (hereinafter referred to as indoor units), where n is an integer greater than 1. They form a closed loop through gas pipes and liquid pipes.

[0018] The outdoor unit includes core components such as a compressor, condenser, and main control board. The compressor is responsible for compressing the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant. The condenser allows the high-temperature, high-pressure gaseous refrigerant to exchange heat with the outside air, and after heat dissipation, it becomes a high-temperature, high-pressure liquid refrigerant. The main control board controls and regulates the entire system.

[0019] Each indoor unit is equipped with components such as an evaporator and a fan, which are mainly responsible for exchanging heat with indoor air to achieve cooling or heating functions to meet the temperature requirements of different rooms.

[0020] Each indoor unit is equipped with an energy-level electronic expansion valve (EVN) along its refrigerant path to achieve precise regulation of refrigerant flow. (Diagram T) in This indicates the ambient temperature of each indoor unit, T. m This indicates the pipe temperature of the indoor unit. In this embodiment, the energy level electronic expansion valve of the indoor unit is also referred to as the indoor unit expansion valve.

[0021] Under normal cooling conditions, the EVN adjusts its opening degree according to the indoor unit's load demand. When the EVN is closed, the refrigerant inflow into the liquid line decreases, leading to an increase in refrigerant circulation on the outdoor unit side and a rise in high-pressure side pressure; simultaneously, the decrease in refrigerant on the indoor unit side causes the exhaust temperature to rise. Conversely, when the EVN is opened wide, the high-pressure side pressure decreases, the throttling effect weakens, causing the low-pressure side pressure to rise, the evaporator pipe temperature rises, and the exhaust temperature drops, forming a thermodynamic regulation closed loop.

[0022] In extreme operating conditions with extremely high outer ring temperatures, the system is prone to abnormal states such as excessively high pressure on the high-pressure side and forced reduction in compressor frequency. In such cases, it is crucial to ensure the following: The outdoor unit heat exchanger effectively dissipates heat, maintaining the exhaust high-pressure saturation temperature higher than the outside ambient temperature, thus ensuring the normal operation of the condensation process. The indoor unit's evaporator effectively absorbs heat, maintaining the pipe temperature below the internal ambient temperature to ensure the continuity of the refrigeration cycle.

[0023] If a fixed opening control strategy for the indoor unit's expansion valve is adopted, the opening may deviate under extreme operating conditions. Excessive opening will lead to increased low pressure and abnormally high pipe temperature, which may cause liquid slugging or decreased system efficiency; insufficient opening will result in insufficient cooling capacity, or even frequent protection shutdowns triggered by abnormal parameters.

[0024] In summary, in cooling mode, if the indoor unit's expansion valve is partially closed, there is more refrigerant on the outside, resulting in higher pressure and less refrigerant on the inside, leading to an increased exhaust temperature. Conversely, if the indoor unit's expansion valve is fully open, the high pressure decreases, there is no throttling, the low pressure increases, the pipe temperature rises, and the exhaust temperature drops. In extreme conditions, with extremely high ambient temperatures, high pressure and extremely low frequency of operation occur, making it crucial to maintain normal cooling performance. For the unit to operate normally, the outdoor unit must maintain an exhaust high-pressure saturation temperature higher than the ambient temperature to allow the heat exchanger to dissipate heat, while the indoor unit's pipe temperature must be lower than the ambient temperature to allow the heat exchanger to absorb heat. However, if the indoor unit's expansion valve has a fixed opening, it is easy for the opening to be too large or too small, resulting in no cooling or frequent protective shutdowns.

[0025] The refrigeration control method, apparatus, electronic equipment, computer-readable storage medium, and computer program product for multi-split air conditioning systems provided in this application aim to solve the aforementioned technical problems of the prior art. For multi-split systems, when the unit detects an abnormal state (high pipe temperature without cooling, outdoor unit not dissipating heat, or suction and liquid return), it adjusts the opening of the indoor unit's expansion valve. During the adjustment process, the changes in indoor unit pipe temperature, high pressure, and exhaust gas are observed. When normal cooling conditions are met, and the high pressure or exhaust gas approaches the protection value, the indoor unit's expansion valve maintains its current opening.

[0026] The technical solutions of this application and their effects are described below through several exemplary embodiments. It should be noted that the following embodiments can be referenced, borrowed from, or combined with each other. Identical terms, similar features, and similar implementation steps in different embodiments will not be repeated.

[0027] This application provides a cooling control method for a multi-split air conditioning system, such as... Figure 2 As shown, the method includes: S101. Under the cooling condition where the outdoor unit ambient temperature is greater than or equal to the first temperature threshold, obtain the opening degree of each indoor unit expansion valve in the current cycle, the compressor parameters of the outdoor unit in the current cycle, and the relationship between the average pipe temperature and the average indoor unit ambient temperature of the multiple indoor units in the current cycle.

[0028] It should be noted that the outdoor unit ambient temperature is the air temperature of the space where the air conditioner outdoor unit is located, which is usually monitored in real time by an outdoor temperature sensor to reflect the impact of outdoor climate conditions on the air conditioning system. This embodiment operates under cooling conditions where the outdoor unit ambient temperature is greater than or equal to a first temperature threshold. In some embodiments, the first temperature threshold is between 35 and 60°C.

[0029] The indoor unit ambient temperature refers to the air temperature of the space where the air conditioner's indoor unit is located. It is monitored by an indoor temperature sensor and reflects the actual temperature or coolness of the environment as perceived by the user. This application embodiment can acquire the ambient temperatures of multiple air conditioner indoor units and calculate the average indoor unit ambient temperature. If there are three air conditioner indoor units that are turned on, and their ambient temperatures are 26.5℃, 26.7℃, and 26.9℃ respectively, then the average indoor unit ambient temperature is determined to be 26.7℃.

[0030] Indoor unit pipe temperature T m Yes, also simply called pipe temperature, is the temperature of the metal pipe wall of the indoor unit's heat exchanger (evaporator or condenser), and is one of the core feedback parameters of the refrigeration system. In cooling mode, the indoor unit's heat exchanger acts as an evaporator, that is, the component where the refrigerant absorbs heat and evaporates. The refrigerant flowing inside the pipes is a low-temperature, low-pressure liquid or gaseous refrigerant that has entered after being throttled by an electronic expansion valve. In this embodiment, the average pipe temperature is obtained by acquiring the pipe temperatures of multiple indoor air conditioning units and calculating the average value. If there are 3 indoor air conditioning units in the operating state, and the pipe temperatures of the 3 indoor air conditioning units are 56.5℃, 56.7℃, and 56.9℃ respectively, then the average pipe temperature is determined to be 56.7℃.

[0031] S102. Determine the opening degree of each indoor unit expansion valve in the next cycle based on the opening degree of each indoor unit expansion valve in the current cycle, the ambient temperature of the outdoor unit of the air conditioner, the compressor parameters, and the magnitude relationship.

[0032] It's important to note that the opening degree of the indoor unit's expansion valve directly determines the refrigerant flow rate into the evaporator. A larger opening degree results in a larger refrigerant flow rate and a stronger cooling effect from the evaporator; conversely, a smaller opening degree results in a smaller refrigerant flow rate and a weaker cooling effect. Based on the opening degree in the current cycle, we can understand the current cooling demand of the indoor unit, providing a basis for adjusting the opening degree in the next cycle.

[0033] The ambient temperature of the outdoor unit is a crucial factor affecting the overall performance of the air conditioning system. When the ambient temperature rises, the condenser's heat dissipation efficiency deteriorates, and the condensing pressure increases, which may lead to increased compressor power consumption and decreased cooling capacity. To maintain the system's cooling efficiency, this application requires adjusting the opening of the indoor unit's expansion valve according to changes in the outdoor ambient temperature. When the outdoor ambient temperature rises, it may be necessary to appropriately increase the opening of the indoor unit's expansion valve to increase refrigerant flow and improve the evaporator's cooling effect.

[0034] The compressor is the core component of an air conditioning system, and its parameters (such as speed, discharge pressure, and suction pressure) directly affect the system's cooling capacity and energy efficiency ratio. Parameters such as compressor speed and discharge pressure reflect the current system load. When the system load increases, the compressor speed increases and the discharge pressure rises. At this time, it is necessary to appropriately increase the opening of the indoor unit's expansion valve to meet the greater cooling demand. Conversely, when the system load decreases, the opening of the indoor unit's expansion valve needs to be reduced.

[0035] The average pipe temperature reflects the average temperature of the refrigerant inside the evaporator, while the average indoor unit ambient temperature reflects the ambient temperature of the indoor unit. The relationship between the two indicates whether the evaporator's cooling effect meets the needs of the indoor unit environment. When the average pipe temperature is higher than the average indoor unit ambient temperature, it indicates that the evaporator's cooling effect is strong. In this case, the opening of the indoor unit's expansion valve can be appropriately reduced to avoid over-cooling. Conversely, when the average pipe temperature is lower than the average indoor unit ambient temperature, the opening of the indoor unit's expansion valve needs to be increased to improve the cooling effect.

[0036] This application embodiment, by comprehensively considering the opening degree of the indoor unit expansion valve in the current cycle, the outdoor unit ambient temperature, the compressor parameters, and the relationship between the average pipe temperature and the average indoor unit ambient temperature, can more accurately determine the current load of the system. By adjusting the opening degree of the indoor unit expansion valve in conjunction with the pipe temperature, ambient temperature, compressor parameters, and outdoor unit ambient temperature, a closed-loop control can be formed, avoiding system oscillations caused by single parameter adjustment, which helps to maintain the stable operation of the evaporator and improve the system's refrigeration efficiency and energy efficiency ratio.

[0037] Based on the above embodiments, as an optional embodiment, the compressor parameters include the exhaust temperature and the compressor exhaust saturation temperature.

[0038] Based on the opening degree of each indoor unit expansion valve in the current cycle, the ambient temperature of the outdoor unit, the compressor parameters, and the magnitude relationship, the opening degree of each indoor unit expansion valve in the next cycle is determined, including: If at least one of the following conditions is met for a continuously preset duration, for each indoor unit expansion valve, the difference between the opening degree of the indoor unit expansion valve in the current cycle and the preset value is taken as the opening degree of the indoor unit expansion valve in the next cycle: The first temperature difference is less than or equal to the superheat threshold; The compressor exhaust saturation temperature is less than or equal to the outdoor unit ambient temperature; The average pipe temperature is greater than or equal to the average indoor unit ambient temperature.

[0039] The first temperature difference in this embodiment is the difference between the compressor discharge temperature and the compressor discharge saturation temperature at the current discharge pressure. The calculation formula is: first temperature difference = discharge temperature - saturation temperature corresponding to the discharge pressure. The discharge saturation temperature is the temperature at which the high-pressure gaseous refrigerant discharged by the compressor begins to condense into a liquid state at the current discharge pressure. In subsequent embodiments, the first temperature difference is also referred to as discharge superheat.

[0040] In other words, this application embodiment configures three conditions for reducing the opening degree of the indoor unit expansion valve. When any one of the above conditions is met, the opening degree of the indoor unit expansion valve will be reduced in the next cycle. The three conditions for reducing the opening degree of the indoor unit expansion valve provided by this application will be analyzed one by one below.

[0041] Condition 1: Exhaust superheat ≤ superheat threshold. As shown in the above examples, exhaust superheat = compressor exhaust temperature - exhaust saturation temperature, representing the degree of complete refrigerant evaporation. When exhaust superheat ≤ threshold, it indicates that the refrigerant flow rate may be too high, resulting in incomplete evaporation of refrigerant at the evaporator outlet, posing a risk of liquid refrigerant entering the compressor. In this case, the solution is to reduce the opening of the indoor unit expansion valve, thereby reducing the refrigerant flow rate and increasing the evaporator outlet superheat to ensure safe compressor operation.

[0042] This application embodiment controls exhaust superheat to prevent liquid refrigerant from entering the compressor, thereby reducing the risk of compressor damage and extending equipment life.

[0043] Condition 2: Compressor discharge saturation temperature ≤ outdoor unit ambient temperature. The discharge saturation temperature reflects the saturation temperature corresponding to the condensing pressure, while the outdoor unit ambient temperature serves as the condenser's heat dissipation reference. When the discharge saturation temperature ≤ the outdoor unit ambient temperature, it indicates that the condensing pressure may be too low (e.g., the ambient temperature is too low or the condenser's heat exchange efficiency is too high), leading to excessive cooling of the refrigerant in the condenser and a decrease in system efficiency. In this case, adjusting the opening of the indoor unit's expansion valve optimizes the refrigerant flow distribution, balances the condensing pressure and evaporating pressure, and improves the overall system efficiency.

[0044] This application embodiment reduces ineffective refrigerant circulation in the system and lowers compressor power consumption by balancing condensing pressure and evaporating pressure.

[0045] Condition 3: Average pipe temperature ≥ Average indoor unit ambient temperature. The average pipe temperature is the average outlet pipe temperature of each indoor unit, reflecting the temperature after refrigerant evaporation. The average indoor unit ambient temperature is the average ambient temperature of each indoor unit. When the average pipe temperature ≥ the average indoor unit ambient temperature, it indicates that the evaporator's cooling capacity is insufficient and cannot meet the indoor load demand. In this case, the solution increases the opening of the indoor unit's expansion valve (using the difference between the current opening and the preset value as the adjustment amount) to increase the refrigerant flow, enhance the evaporator's cooling capacity, and quickly reduce the indoor temperature.

[0046] The embodiments of this application do not limit the size of the preset duration, for example, it can be 1-3 minutes.

[0047] This application embodiment quickly responds to changes in indoor load and avoids temperature fluctuations by comparing the average pipe temperature with the indoor unit's ambient temperature in real time.

[0048] Based on the above embodiments, as an optional embodiment, the opening degree of each indoor unit expansion valve is adjusted sequentially according to the determined opening degree of each indoor unit expansion valve in the next cycle.

[0049] In refrigeration systems, the core mechanism of sequentially adjusting the expansion valve openings of each indoor unit to avoid countercurrents lies in decoupling the strong coupling relationships between multiple variables through timing control, ensuring the dynamic balance of system parameters such as pressure, flow rate, and temperature. In multi-indoor-unit systems, adjusting the expansion valve opening directly alters the refrigerant flow distribution, thereby affecting key parameters such as evaporation pressure, compressor load, and condensation pressure. If multiple valves are adjusted simultaneously, the cumulative effect of changes in the flow rates of each indoor unit may cause a sudden increase or decrease in the total system flow rate, leading to drastic fluctuations in evaporation pressure, abnormal compressor suction conditions (such as excessively low superheat leading to liquid slugging risk), or uncontrolled condensation pressure, ultimately resulting in parameter oscillations, performance degradation, or even equipment damage.

[0050] This application sequentially adjusts a multivariable problem into a single-variable control through time-sharing operation: when only one valve is adjusted at a time, other system parameters remain stable, and the adjustment only affects the refrigerant flow and evaporator status of the current indoor unit. After adjustment, the system needs a short period to reach steady state again. During this time, the compressor can compensate for pressure fluctuations by changing its frequency or adjusting the position of the slide valve, and other indoor units are also protected from interference because their valves are not moved. For example, if the opening of the expansion valves of indoor units A and B needs to be reduced simultaneously, simultaneous adjustment will cause a sudden drop in total flow, a sudden increase in evaporation pressure, and a decrease in the compressor's suction specific volume; however, when adjusting sequentially, reducing the opening of A first leads to system steady state, with a slight increase in evaporation pressure, which the compressor compensates for by increasing its frequency; when reducing the opening of B, the system has already adapted to the change in A, and the decrease in total flow is more gradual, avoiding drastic pressure fluctuations.

[0051] In some embodiments, when the opening of the expansion valve of each indoor unit is reduced sequentially under refrigeration conditions, the adjustment is made from the far end to the near end, that is, the indoor unit farthest from the compressor is adjusted first, and then the indoor units closer to the compressor are gradually adjusted.

[0052] It's important to note that in a refrigeration system, after the refrigerant is discharged from the compressor, it passes through the condenser and expansion valve into the evaporator, and finally returns to the compressor via the return gas pipe. This process exhibits a significant pressure gradient: the further the indoor unit is from the compressor, the lower its evaporator inlet pressure. If the adjustment sequence is reversed compared to the refrigerant flow direction, the reduced flow to the near-end indoor unit will cause more refrigerant to rush to the far end. However, the expansion valve at the far end has not yet been adjusted, and its opening is still relatively large. This could lead to evaporator overcooling or excessively low return gas superheat due to a sudden increase in flow. Adjusting from the far end to the near end, by first reducing the flow to the far-end indoor unit, its refrigerant demand can be proactively reduced, preventing flow fluctuations caused by near-end adjustments from being transmitted to the far end. At this point, as the pressure at the far end decreases, the system's total return gas pressure also decreases, providing a buffer for stabilizing the compressor's suction state when adjusting the near-end indoor unit later—when the near-end indoor unit is adjusted, its evaporator inlet pressure has already partially adapted to the system change, and the impact of reduced flow on the return gas pressure is smaller.

[0053] It should be understood that compressor suction superheat is a critical parameter for ensuring operational safety. When adjusting from the near end to the far end, the refrigerant temperature at the evaporator outlet of the near-end indoor unit may increase due to reduced flow, but the return gas temperature of the far-end indoor unit remains low due to a lag in adjustment. The total return gas superheat of the mixed system may fall below the safe threshold. However, when adjusting from the far end to the near end, first reducing the opening of the expansion valve of the far-end indoor unit causes its evaporator outlet refrigerant temperature to rise due to reduced flow, thus increasing the return gas superheat. This provides a safety margin for subsequent adjustments to the total superheat of the near-end indoor unit. For example, if the superheat of the far-end indoor unit reaches a certain temperature before adjusting the near-end indoor unit, even if its return gas temperature increases due to reduced flow, the total superheat of the system can still be maintained within a safe range, preventing compressor damage due to liquid carryover during suction.

[0054] Furthermore, the system exhibits a delay in responding to changes in the expansion valve opening, particularly noticeable in the remote indoor unit due to its longer piping. When adjusting from the near end to the far end, the pressure change from the near-end unit needs to be transmitted to the far end via refrigerant flow, a process that can take several seconds to tens of seconds. If the remote indoor unit is adjusted during this period, its response may be overcompensated or delayed due to the system's unstable state, leading to repeated fluctuations in parameters such as evaporation pressure and superheat, potentially extending the system's steady-state time to over 180 seconds. However, when adjusting from the far end to the near end, the remote indoor unit is adjusted first. Its parameter changes (such as pressure and temperature) primarily affect the local system. The near-end indoor unit, being downstream of the refrigerant flow, is less directly affected by the adjustment from the far end. Once the remote indoor unit has completed its adjustment and stabilized, the near-end indoor unit can then be adjusted. By this time, the system has partially adapted to the changes from the far end, and the impact of the near-end adjustment is more easily absorbed by the system. For example, in large commercial air conditioning systems, after the remote indoor unit is adjusted, the compressor can quickly respond to local pressure changes through frequency fine-tuning, providing a more stable benchmark for near-end adjustments and avoiding exhaust temperature fluctuations.

[0055] Based on the above embodiments, as an optional embodiment, the compressor parameters include at least one of the compressor discharge saturation temperature, discharge temperature, and discharge pressure; If at least one of the following conditions is met, the opening degree of the indoor unit expansion valve in the current cycle shall be taken as the opening degree of the indoor unit expansion valve in the next cycle: The exhaust superheat (first temperature difference) is greater than the superheat threshold, the compressor exhaust saturation temperature is greater than the outdoor unit ambient temperature, and the average pipe temperature is less than the average indoor unit ambient temperature. The exhaust pressure is greater than the pressure threshold; The exhaust temperature is greater than the second temperature threshold.

[0056] This application provides three conditions for maintaining the opening degree of the indoor unit's expansion valve unchanged: For condition a: exhaust superheat > superheat threshold, exhaust saturation temperature > outdoor unit ambient temperature, and average pipe temperature < average indoor unit ambient temperature. Exhaust superheat > threshold: reflects the superheat state of the refrigerant at the evaporator outlet. If the superheat is too high, it indicates insufficient refrigerant flow in the evaporator, leading to incomplete evaporation and a decrease in system cooling capacity. In this case, it is necessary to increase the opening of the expansion valve to increase the refrigerant flow and reduce the superheat.

[0057] The exhaust saturation temperature is directly related to the condensing pressure. When it is higher than the outdoor unit ambient temperature, it indicates that the condensing pressure is within a reasonable range (condenser heat exchange efficiency is normal), and the system has the potential to optimize energy efficiency by adjusting the expansion valve.

[0058] The average pipe temperature represents the average temperature of the refrigerant inside the evaporator. If it is lower than the indoor ambient temperature, it indicates that the evaporator has excessive cooling capacity. In this case, the opening of the expansion valve should be reduced to decrease the refrigerant flow rate in order to balance supply and demand.

[0059] When condition a is met, the system is in a contradictory state—high superheat requires the expansion valve to be opened further, while low pipe temperature requires the expansion valve to be closed less. In this case, the embodiment of this application chooses to maintain the current opening degree to avoid system oscillation caused by a single parameter adjustment (such as opening further leading to a further decrease in pipe temperature, or closing less leading to a further increase in superheat), reflecting the priority of ensuring system stability.

[0060] Condition b: Discharge pressure > pressure threshold. Discharge pressure reflects the load on the condenser side. When the pressure exceeds the pressure threshold, it may be due to poor condenser heat dissipation (such as dirt blockage or insufficient airflow) or excessive refrigerant charge. If the current expansion valve opening is maintained at this time, it may aggravate the compressor load or even trigger high-pressure protection shutdown. In this embodiment, by maintaining the current opening, the refrigerant flow is avoided from being further increased (increasing the opening will aggravate the rise in condensing pressure), providing a buffer time for the system. In some embodiments, the high-pressure problem can also be alleviated by cleaning the condenser and adjusting the fan speed.

[0061] Condition c: Discharge temperature > second temperature threshold. Discharge temperature is a key indicator of compressor operating safety. When it exceeds the second temperature threshold, the compressor may overheat due to excessive compression ratio or insufficient refrigerant flow. In this embodiment, maintaining the current opening degree prevents more serious consequences from blind adjustments. For example, increasing the opening degree reduces return gas superheat, potentially leading to wet compression; decreasing the opening degree causes a further increase in discharge pressure. In some embodiments, other protective measures may be combined, such as reducing compressor frequency or starting the cooling fan to ensure safety.

[0062] It should be noted that in condition a, the system faces the contradictory demands of both "high superheat" and "low pipe temperature." Maintaining the opening degree can prevent parameter fluctuations caused by frequent adjustments (such as alternating over-limits of superheat and pipe temperature), thus improving system stability. In conditions b and c, maintaining the opening degree provides the system with a buffer time to cope with abnormal operating conditions, avoiding a chain reaction caused by immediate adjustments. For example, reducing the opening degree under high-pressure conditions may lead to refrigerant shortage in the evaporator, further exacerbating the high pressure.

[0063] The superheat threshold is between 0 and 15°C.

[0064] Based on the above embodiments, as an optional embodiment, the preset value is between 2 and 10 pulses (PLS).

[0065] Based on the above embodiments, as an optional embodiment, the first temperature threshold is between 35 and 60°C; The pressure threshold is between 4.3 and 4.6 MPa; The second temperature threshold is between 105 and 115°C.

[0066] Please see Figure 3 The figure illustrates a schematic flowchart of a refrigeration control method provided in an embodiment of this application, as shown in the figure, which includes: S201. Under the cooling condition where the outdoor unit ambient temperature is greater than or equal to the first temperature threshold, obtain the opening degree of each indoor unit expansion valve in the current cycle, the compressor parameters of the outdoor unit in the current cycle, and the pipe temperature and indoor unit ambient temperature of each indoor unit in the current cycle. The compressor parameters include at least one of the compressor discharge saturation temperature, discharge temperature, and discharge pressure. S202. Based on the pipe temperatures of multiple indoor air conditioning units in the current cycle, determine the average pipe temperature of each indoor air conditioning unit in the current cycle; based on the ambient temperature of multiple indoor air conditioning units in the current cycle, determine the average ambient temperature of multiple indoor air conditioning units in the current cycle. S203. Determine the relationship between the average pipe temperature and the average indoor unit ambient temperature of multiple air conditioning indoor units in the current cycle; S204a. When the exhaust superheat is less than or equal to the superheat threshold, reduce the opening of the indoor unit expansion valve in the next cycle. S204b. When the compressor exhaust saturation temperature is less than or equal to the outdoor unit ambient temperature, reduce the opening degree of the indoor unit expansion valve in the next cycle. S204c, If the average pipe temperature is greater than or equal to the average indoor unit ambient temperature, reduce the opening degree of the indoor unit expansion valve in the next cycle. S204d. When the exhaust superheat is greater than the superheat threshold, the compressor exhaust saturation temperature is greater than the outdoor unit ambient temperature, and the average pipe temperature is less than the average indoor unit ambient temperature, the opening of the indoor unit expansion valve remains unchanged in the next cycle. S204e: When the exhaust pressure is greater than the pressure threshold, keep the opening of the indoor unit expansion valve unchanged in the next cycle; S204f: When the exhaust temperature is greater than the second temperature threshold, keep the opening of the indoor unit expansion valve unchanged in the next cycle.

[0067] This application provides a cooling control method for a multi-split air conditioning system. After the unit has been running normally in cooling mode for a period of time, such as 20 minutes, if the i-th indoor unit detects that the following four conditions are met for 2 consecutive minutes: When the ambient temperature of the outdoor unit is T ao ≥X, the multi-split unit operates stably in cooling mode (i.e., the frequency / indoor unit load is stable), where X is a fixed constant, 60℃; When at least one of the following conditions is met for more than 5 minutes, according to the formula: EVNi （n+1） =EVNi （n） -Y, adjust the opening degree EVN of the indoor unit expansion valve of the i-th indoor unit in the (n+1)th cycle. i（n+1） Y is a fixed constant, ranging from 2 to 10 pls; The average temperature T of the indoor unit pipes m ave The average temperature T, which is greater than or equal to the indoor ambient temperature, is in ave ; Compressor exhaust saturation temperature T c Less than or equal to the outdoor unit ambient temperature T ao ; Exhaust superheat T dSH Less than or equal to A; A is a fixed constant, ranging from 0 to 15℃.

[0068] The indoor unit expansion valves of all indoor units shall maintain their current opening degree when at least one of the following conditions is met (EVNi). （n+1） =EVNi （n） ): T m ave +B≤T in ave T c≥T ao +C and T dSH ≥D; Exhaust pressure Pc≥E; Exhaust temperature Td≥F; Wherein, B is a fixed constant, ranging from 2 to 5℃; C is a fixed constant, ranging from 0 to 5℃; D is a fixed constant, ranging from 18 to 35℃; E is a fixed constant, ranging from 4.3 to 4.6 MPa; and F is a fixed constant, ranging from 105 to 115℃.

[0069] This application provides a refrigeration control device for a multi-split air conditioning system, such as... Figure 4 As shown, the refrigeration control device may include: a parameter acquisition module 401 and an opening degree determination module 402, wherein, The parameter acquisition module 401 is used to acquire the opening degree of each indoor unit expansion valve in the current cycle, the compressor parameters of the outdoor unit in the current cycle, and the relationship between the average pipe temperature and the average indoor unit ambient temperature of the multiple indoor units in the current cycle when the outdoor unit ambient temperature is greater than or equal to the first temperature threshold. The opening degree determination module 402 is used to determine the opening degree of each indoor unit expansion valve in the next cycle based on the opening degree of each indoor unit expansion valve in the current cycle, the outdoor unit ambient temperature, the compressor parameters, and the size relationship.

[0070] The apparatus in this application embodiment can execute the method provided in this application embodiment, and the implementation principle is similar. The actions performed by each module in the apparatus of each embodiment of this application correspond to the steps in the method of each embodiment of this application. For detailed functional descriptions of each module of the apparatus, please refer to the descriptions in the corresponding methods shown above, which will not be repeated here.

[0071] This application provides an electronic device, including a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of a refrigeration control method for a multi-split air conditioning system. Compared with related technologies, this method can achieve the following: by comprehensively considering the opening degree of the indoor unit expansion valve in the current cycle, the outdoor unit ambient temperature, the compressor parameters, and the relationship between the average pipe temperature and the average indoor unit ambient temperature, the current load of the system can be more accurately determined. By adjusting the opening degree of the indoor unit expansion valve in conjunction with the pipe temperature, ambient temperature, compressor parameters, and outdoor unit ambient temperature, a closed-loop control can be formed, avoiding system oscillations caused by single parameter adjustments. This helps maintain the stable operation of the evaporator, improves the system's refrigeration efficiency and energy efficiency ratio, ensures the air conditioning unit can still operate safely when refrigerating at temperatures above 60°C, and ensures that the air conditioner has good output capacity in high-temperature refrigeration environments.

[0072] In one alternative embodiment, an electronic device is provided, such as Figure 5 As shown, Figure 5 The illustrated electronic device 4000 includes a processor 4001 and a memory 4003. The processor 4001 and the memory 4003 are connected, for example, via a bus 4002. Optionally, the electronic device 4000 may further include a transceiver 4004, which can be used for data interaction between the electronic device and other electronic devices, such as sending and / or receiving data. It should be noted that in practical applications, the transceiver 4004 is not limited to one type, and the structure of the electronic device 4000 does not constitute a limitation on the embodiments of this application.

[0073] Processor 4001 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 4001 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0074] Bus 4002 may include a pathway for transmitting information between the aforementioned components. Bus 4002 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 4002 can be divided into address bus, data bus, control bus, etc. For ease of representation, bus 4002 is represented by only one thick line in the figure, but this does not indicate that there is only one bus or one type of bus.

[0075] The memory 4003 may be ROM (Read Only Memory) or other types of static storage devices capable of storing static information and instructions, RAM (Random Access Memory) or other types of dynamic storage devices capable of storing information and instructions, or EEPROM (Electrically Erasable Programmable Read Only Memory), CD-ROM (Compact Disc Read Only Memory) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, other magnetic storage devices, or any other medium capable of carrying or storing computer programs and capable of being read by a computer, without limitation herein.

[0076] The memory 4003 stores computer programs that execute embodiments of this application, and its execution is controlled by the processor 4001. The processor 4001 executes the computer programs stored in the memory 4003 to implement the steps shown in the foregoing method embodiments.

[0077] This application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it can implement the steps and corresponding content of the aforementioned method embodiments.

[0078] This application also provides a computer program product, including a computer program that, when executed by a processor, can implement the steps and corresponding content of the aforementioned method embodiments.

[0079] The terms "first," "second," "third," "fourth," "1," "2," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in a sequence other than that shown in the illustrations or text descriptions.

[0080] It should be understood that although arrows indicate various operation steps in the flowcharts of this application's embodiments, the order in which these steps are implemented is not limited to the order indicated by the arrows. Unless explicitly stated herein, in some implementation scenarios of this application's embodiments, the implementation steps in each flowchart can be executed in other orders as required. Furthermore, some or all steps in each flowchart, based on the actual implementation scenario, may include multiple sub-steps or multiple stages. Some or all of these sub-steps or stages can be executed at the same time, and each sub-step or stage can also be executed at different times. In scenarios where execution times differ, the execution order of these sub-steps or stages can be flexibly configured according to requirements, and this application's embodiments do not limit this.

[0081] The above description is only an optional implementation method for some implementation scenarios of this application. It should be noted that for those skilled in the art, other similar implementation methods based on the technical concept of this application without departing from the technical concept of this application also fall within the protection scope of the embodiments of this application.

Claims

1. A refrigeration control method for a multi-split air conditioning system, characterized in that, The multi-split air conditioning system includes an outdoor unit and multiple indoor units, each indoor unit including an indoor unit expansion valve, and the method includes: Under the cooling condition where the outdoor unit ambient temperature is greater than or equal to the first temperature threshold, the opening degree of each indoor unit expansion valve in the current cycle, the compressor parameters of the outdoor unit in the current cycle, and the relationship between the average pipe temperature and the average indoor unit ambient temperature of the multiple indoor units in the current cycle are obtained. The opening degree of each indoor unit expansion valve in the next cycle is determined based on the opening degree of each indoor unit expansion valve in the current cycle, the ambient temperature of the outdoor unit, the compressor parameters, and the magnitude relationship.

2. The method according to claim 1, characterized in that, The compressor parameters include the exhaust temperature and the compressor exhaust saturation temperature; The step of determining the opening degree of each indoor unit expansion valve in the next cycle based on the opening degree of each indoor unit expansion valve in the current cycle, the outdoor unit ambient temperature, the compressor parameters, and the magnitude relationship includes: If at least one of the following conditions is met for a continuously preset duration, for each indoor unit expansion valve, the difference between the opening degree of the indoor unit expansion valve in the current cycle and the preset value is taken as the opening degree of the indoor unit expansion valve in the next cycle: The first temperature difference is less than or equal to the superheat threshold, and the first temperature difference is the difference between the exhaust temperature and the compressor exhaust saturation temperature; The compressor exhaust saturation temperature is less than or equal to the outdoor unit ambient temperature; The average pipe temperature is greater than or equal to the average indoor unit ambient temperature.

3. The method according to claim 1, characterized in that, The compressor parameters include at least one of the compressor discharge saturation temperature, discharge temperature, and discharge pressure; If at least one of the following conditions is met, the opening degree of the indoor unit expansion valve in the current cycle shall be taken as the opening degree of the indoor unit expansion valve in the next cycle: The first temperature difference is greater than the superheat threshold, the compressor exhaust saturation temperature is greater than the outdoor unit ambient temperature, and the average pipe temperature is less than the average indoor unit ambient temperature. The first temperature difference is the difference between the exhaust temperature and the compressor exhaust saturation temperature. The exhaust pressure is greater than the pressure threshold; The exhaust temperature is greater than the second temperature threshold.

4. The method according to claim 2, characterized in that, Also includes: Based on the determined opening degree of each indoor unit expansion valve in the next cycle, adjust the opening degree of each indoor unit expansion valve in sequence.

5. The method according to claim 2 or 3, characterized in that, The superheat threshold is between 0 and 15°C.

6. The method according to claim 2, characterized in that, The preset value is between 2 and 10 PLS.

7. The method according to claim 3, characterized in that, The first temperature threshold is between 35 and 60°C; The pressure threshold is between 4.3 and 4.6 MPa; The second temperature threshold is between 105 and 115°C.

8. A refrigeration control device for a multi-split air conditioning system, characterized in that, The multi-split air conditioning system includes multiple indoor air conditioning units, and the device includes: The parameter acquisition module is used to acquire the opening degree of each indoor unit expansion valve in the current cycle, the compressor parameters of the outdoor unit in the current cycle, and the relationship between the average pipe temperature and the average indoor unit ambient temperature of the multiple indoor units in the current cycle when the outdoor unit ambient temperature is greater than or equal to the first temperature threshold. The opening degree determination module is used to determine the opening degree of each indoor unit expansion valve in the next cycle based on the opening degree of each indoor unit expansion valve in the current cycle, the ambient temperature of the outdoor unit, the compressor parameters, and the magnitude relationship.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the refrigeration control method for the multi-split air conditioning system according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the refrigeration control method for the multi-split air conditioning system according to any one of claims 1-7.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the refrigeration control method for the multi-split air conditioning system according to any one of claims 1-7.

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