Control method of multi-connected air conditioner, multi-connected air conditioner and storage medium

Abstract

The application discloses a control method of a multi-connected air conditioner, the multi-connected air conditioner and a computer readable storage medium, comprising the following steps: receiving an indoor unit opening instruction, determining a target indoor unit from the opened indoor unit and the indoor unit opening instruction corresponding to the to-be-opened indoor unit, the target capacity requirement of the target indoor unit being greater than that of other indoor units except the target indoor unit; determining a target evaporation temperature of the target indoor unit; and performing a preset operation, the preset operation comprising at least one of the following: adjusting the compressor operation frequency of the multi-connected air conditioner according to the target evaporation temperature and the actual evaporation temperature of the opened indoor unit; adjusting the opening degree of the electronic expansion valve of the opened indoor unit according to the target superheat degree of the opened indoor unit; and gradually opening the electronic expansion valve of the to-be-opened indoor unit according to a preset step number. The embodiment of the application can stabilize the room temperature of the opened indoor unit and reduce the fluctuation.

Description

Technical Field

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

[0002] A multi-split air conditioner includes one outdoor unit and at least two indoor units, all of which are connected to the outdoor unit. Multiple indoor units can be started simultaneously. However, in practical applications, the indoor units usually do not start at the same time. Therefore, it is possible that some indoor units may be in rooms where the room has already reached the set temperature, while other indoor units are still running.

[0003] When a new indoor unit is turned on, the cooling capacity demand changes. The compressor's operating frequency is then calculated based on the new demand. The electronic expansion valve of the newly turned-on unit opens at its initial degree and then adjusts according to the superheat of the unit. As the compressor's operating frequency increases, the room temperature where the already heated indoor unit is located will rise. However, the initial opening of the electronic expansion valve of the newly turned-on unit is larger, resulting in a decrease in the cooling capacity of the already heated indoor unit. This leads to large temperature fluctuations in the room where the already heated indoor unit is located.

[0004] It should be noted that the above content is only used to help understand the technical problem solved by the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a control method for a multi-split air conditioner, a multi-split air conditioner, and a storage medium, which aims to minimize the impact on the room temperature of the already heated indoor unit when the indoor unit is turned on, and to reduce temperature fluctuations in the room where the already heated indoor unit is located.

[0006] Based on this, the present invention provides a control method for a multi-split air conditioner, the control method comprising the following steps:

[0007] Receive an indoor unit start command, determine a target indoor unit from the already started indoor units and the indoor units to be started corresponding to the indoor unit start command, and the target capacity requirement of the target indoor unit is greater than that of other indoor units except the target indoor unit;

[0008] Determine the target evaporation temperature of the target indoor unit;

[0009] Perform a preset operation, which includes at least one of the following:

[0010] The compressor operating frequency of the multi-split air conditioner is adjusted according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on;

[0011] Adjust the opening degree of the electronic expansion valve of the indoor unit that has been turned on according to the target superheat of the indoor unit that has been turned on;

[0012] The electronic expansion valve of the indoor unit to be turned on is gradually opened according to the preset number of steps.

[0013] Optionally, the step of determining the target indoor unit from the already powered-on indoor units and the indoor unit to be powered-on corresponding to the indoor unit power-on command includes:

[0014] The first temperature-reaching evaporation temperature corresponding to when the indoor ambient temperature of the indoor unit that is already turned on reaches the set temperature, and the second temperature-reaching evaporation temperature corresponding to when the indoor ambient temperature of the indoor unit that is to be turned on reaches the set temperature are obtained.

[0015] When the first temperature reached by evaporation is less than or equal to the second temperature reached by evaporation, the target indoor unit is determined to be the indoor unit that has been turned on.

[0016] When the first evaporation temperature is greater than the second evaporation temperature, the target indoor unit is determined to be the indoor unit to be turned on.

[0017] Optionally, the step of determining the target evaporation temperature of the target indoor unit includes:

[0018] Determine the instantaneous capacity requirements of the target internal unit;

[0019] The target evaporation temperature of the target indoor unit is determined based on the instantaneous capacity requirement, the rated nominal capacity of the target indoor unit, the indoor ambient temperature where the target indoor unit is located, the outdoor ambient temperature, the first correction value, the second correction value, and the third correction value.

[0020] Optionally, the step of adjusting the operating frequency of the compressor of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on includes:

[0021] Obtain the first difference between the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on;

[0022] The target frequency parameter of the compressor is determined based on the mapping relationship between the first difference and the compressor frequency parameter. The target frequency parameter includes a frequency adjustment value and an adjustment period.

[0023] Adjust the operating frequency of the compressor according to the target frequency parameters.

[0024] Optionally, after the step of adjusting the compressor operating frequency of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on, the method further includes:

[0025] Obtain a second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature;

[0026] When the second difference is less than the first preset temperature difference, the rate of decrease of the indoor ambient temperature where the indoor unit to be turned on is located is obtained;

[0027] When the rate of decrease is less than the preset rate of decrease, the second correction value of the target evaporation temperature is reduced, and the process returns to the step of determining the target evaporation temperature of the target indoor unit.

[0028] Optionally, the step of reducing the target evaporation temperature when the descent rate is less than the preset descent rate, and then returning to the step of determining the target evaporation temperature of the indoor unit, includes:

[0029] When the rate of descent is less than the preset rate of descent, a second correction value for the target evaporation temperature is obtained;

[0030] When the second correction value is greater than the second correction threshold, the second correction value of the target evaporation temperature is reduced, and the process returns to the step of determining the target evaporation temperature of the target indoor unit.

[0031] If the second correction value is less than or equal to the second correction threshold, return directly to the step of determining the target evaporation temperature of the target indoor unit.

[0032] Optionally, the step of controlling the electronic expansion valve of the indoor unit to be turned on to gradually open according to a preset number of steps includes:

[0033] At preset time intervals, the electronic expansion valve of the indoor unit to be opened is controlled to open for a preset number of steps until the electronic expansion valve of the indoor unit to be opened is opened to a preset degree.

[0034] Optionally, the method further includes:

[0035] After the electronic expansion valve of the indoor unit to be turned on is opened to the preset opening degree, the adjustment parameters of the electronic expansion valve are determined according to the preset superheat of the indoor unit to be turned on.

[0036] Adjust the electronic expansion valve according to the adjustment parameters.

[0037] Optionally, the step of adjusting the opening degree of the electronic expansion valve of the indoor unit based on the target superheat of the indoor unit includes:

[0038] The target superheat of the indoor unit is calculated based on the target evaporation temperature of the target indoor unit, the instantaneous capacity requirement of the indoor unit that has been turned on, the rated nominal capacity of the indoor unit that has been turned on, the indoor ambient temperature where the indoor unit that has been turned on is located, the outdoor ambient temperature, and the superheat correction parameters.

[0039] Adjust the opening degree of the electronic expansion valve of the already opened indoor unit according to the target superheat.

[0040] Optionally, the preset operation further includes:

[0041] When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature is obtained.

[0042] When the second difference is less than the first preset temperature difference, the rate of change of the indoor ambient temperature where the target indoor unit is located is obtained;

[0043] When the rate of change is less than the preset rate of change, a fourth difference between the indoor ambient temperature where the target indoor unit is located and the set temperature is obtained;

[0044] When the fourth difference is outside the second preset temperature difference range, the first correction value of the target evaporation temperature is adjusted according to the fourth difference, and the process returns to the step of determining the target evaporation temperature of the target indoor unit.

[0045] Optionally, before the step of determining the target evaporation temperature of the target indoor unit, the method further includes:

[0046] When the target indoor unit is determined to be the already turned-on indoor unit, the second correction value of the target evaporation temperature is increased, so that the target evaporation temperature of the target indoor unit is corrected using the increased second correction value;

[0047] When the target indoor unit is determined to be the indoor unit to be turned on, the second correction value is set to zero.

[0048] Optionally, the preset operation further includes:

[0049] When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, and the target indoor unit is the indoor unit to be turned on, a second correction value and a third correction value are obtained.

[0050] When the second and third correction values ​​are within the range of the first correction value, the opening degree of the electronic expansion valve of the already opened indoor unit is adjusted using the preset superheat of the target indoor unit.

[0051] When the second and third correction values ​​are outside the range of the first correction value, the target superheat of the target indoor unit is determined based on the target evaporation temperature determined according to the instantaneous capacity requirement of the target indoor unit, and the opening of the electronic expansion valve of the target indoor unit is adjusted according to the target superheat.

[0052] Optionally, the preset operation further includes:

[0053] When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the target evaporation temperature is determined based on the instantaneous capacity requirements of other indoor units besides the target indoor unit.

[0054] The target superheat of the other indoor units is determined based on the target evaporation temperature, and the opening of the electronic expansion valve of the other indoor units is adjusted according to the target superheat.

[0055] Optionally, the method further includes:

[0056] The fifth difference between the ambient temperature of the other indoor unit and the corresponding set temperature of the other indoor unit;

[0057] When the fifth difference is greater than the second preset temperature difference and the target superheat of the other indoor unit is greater than the preset threshold, after reducing the correction parameter of the target superheat of the other indoor unit, the process returns to the step of determining the target evaporation temperature based on the instantaneous capacity requirements of the other indoor units besides the target indoor unit.

[0058] When the fifth difference is less than the second preset temperature difference and the target superheat of the other indoor unit is less than the preset threshold, after increasing the correction parameter of the target superheat of the other indoor unit, the process returns to the step of determining the target evaporation temperature based on the instantaneous capacity requirements of the other indoor units besides the target indoor unit.

[0059] Optionally, the preset operation further includes:

[0060] Adjust the speed of the indoor unit fan according to the adjusted operating frequency of the compressor.

[0061] To achieve the above objectives, the present invention also provides a multi-split air conditioner, the multi-split air conditioner including a memory, a processor, and a control program stored in the memory and executable on the processor, wherein when the control program is executed by the processor, it implements the steps of the control method for the multi-split air conditioner as described above.

[0062] In addition, the present invention also provides a storage medium storing a control program, which, when executed by a processor, implements the various steps of the control method for a multi-split air conditioner as described above.

[0063] To achieve the above objectives, the present invention provides a control method for a multi-split air conditioner. The present invention also provides a multi-split air conditioner, the multi-split air conditioner including a memory, a processor, and a control program stored in the memory and executable on the processor. When the control program is executed by the processor, it implements the steps of the control method for the multi-split air conditioner as described above.

[0064] The present invention also provides a computer-readable storage medium storing a control program, which, when executed by a processor, implements the various steps of the control method for a multi-split air conditioner as described above.

[0065] The present invention provides a control method for a multi-split air conditioner, a multi-split air conditioner, and a storage medium. In this embodiment, upon receiving an indoor unit start command, a target indoor unit is determined from the already started indoor units and the corresponding indoor units to be started according to the start command. The target indoor unit's target capacity requirement is greater than that of other indoor units besides the target indoor unit. The target evaporation temperature of the target indoor unit is determined. A preset operation is executed, such as adjusting the compressor operating frequency of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the already started indoor units. Since the difference between the actual evaporation temperature of the already started indoor units and the target evaporation temperature is small, and newly started indoor units with higher temperatures in the middle are not considered, the change in the compressor operating frequency is small. Thus, the cooling capacity of the compressor is relatively stable, avoiding excessive cooling capacity that could affect the temperature of the room where the already started indoor units are located.

[0066] And / or, perform preset operations such as: adjusting the opening of the electronic expansion valve of the indoor unit based on the target superheat of the indoor unit; the target superheat is adjusted in real time according to the target superheat of the indoor unit, so that the indoor ambient temperature of the indoor unit tends to the set temperature, such that the difference is within a preset range. In this way, the cooling capacity provided by the indoor unit meets the indoor demand and can avoid temperature fluctuations in the room where the indoor unit is located.

[0067] And / or, execute a preset operation diagram: control the electronic expansion valve of the indoor unit to be turned on to gradually open according to a preset number of steps. The electronic expansion valve of the indoor unit to be turned on opens gradually from small to large, so that the refrigerant flow distributed to the indoor unit to be turned on is initially small and then gradually increases. This avoids a situation where a large amount of refrigerant is distributed to the indoor unit to be turned on when it is turned on, which would cause a sudden decrease in the amount of refrigerant in the already turned-on indoor unit and result in a significant drop in temperature. This also ensures that the cooling capacity of the already turned-on indoor unit is relatively stable, and the room temperature fluctuates less. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the hardware architecture of a multi-split air conditioner according to an embodiment of the present invention;

[0069] Figure 2 This is a flowchart illustrating the first embodiment of the control method for multi-split air conditioners of the present invention;

[0070] Figure 3 for Figure 2 A detailed embodiment of step S30 is illustrated in the flowchart.

[0071] Figure 4 for Figure 2 A schematic diagram of another detailed embodiment of step S30;

[0072] Figure 5 for Figure 2 A schematic diagram of another detailed embodiment of step S30;

[0073] Figure 6 This is a flowchart illustrating the second embodiment of the control method for multi-split air conditioners of the present invention;

[0074] Figure 7 This is a flowchart illustrating the third embodiment of the control method for multi-split air conditioners of the present invention;

[0075] Figure 8 This is a flowchart illustrating the fourth embodiment of the control method for multi-split air conditioners of the present invention;

[0076] Figure 9 This is a flowchart illustrating the fifth embodiment of the control method for multi-split air conditioners of the present invention.

[0077] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0078] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0079] In a scenario where, during cooling operation, one indoor unit is already in a room that has reached the set temperature, and another indoor unit is turned on, the temperature in the room where the already-set indoor unit is located will fluctuate. Related technologies aim to improve this issue by adjusting the compressor control strategy, the indoor unit's electronic expansion valve control strategy, or the indoor unit fan control strategy and the outdoor unit fan control strategy.

[0080] If, after the indoor unit is turned on, the change in the capacity requirement of a single indoor unit is greater than 30% or 4kW of the total capacity requirement before the change, the compressor will run directly at the recalculated initial frequency, and then enter the target T2 temperature control after 1 minute, with the protection action taking priority.

[0081] After entering the target temperature control, the compressor's operating frequency is adjusted based on the difference between the average actual evaporation temperature of the currently operating indoor unit and the target evaporation temperature, so that the actual evaporation temperature approaches the target evaporation temperature.

[0082] For indoor units that have reached the set temperature, the electronic expansion valve control maintains the superheat level. For indoor units that have not yet reached the set temperature, the electronic expansion valve control first opens to the initial opening and holds for 5 minutes before switching to superheat control.

[0083] For example, if the indoor unit fan has reached the set temperature, it will turn on to the set speed when the user has set the airflow level; if the user has not set a level, it will turn on every 30 seconds based on the difference between the room temperature and the set temperature.

[0084] For indoor unit fans that have not reached the set temperature, the fan will turn on to the set setting if the user has set the airflow level; otherwise, it will turn on every 30 seconds based on the difference between the room temperature and the set temperature.

[0085] For the outdoor unit fan control, maintain the cold outlet temperature control, and adjust the condenser outlet temperature every 30 seconds.

[0086] The aforementioned related technologies may have the following problems:

[0087] For example, in question 1: after the indoor unit in a room is turned on, the room temperature fluctuates greatly even though it has reached the set temperature.

[0088] When a newly turned-on indoor unit's electronic expansion valve opens directly to its initial position, the refrigerant flow to the already turned-on unit suddenly decreases, resulting in a sudden decrease in cooling capacity and a rapid increase in room temperature. For a period after startup, the actual evaporation temperature of the newly turned-on indoor unit is higher than the actual evaporation temperature of the refrigerant, causing the calculated difference between the average actual evaporation temperature of the unit with the required capacity and the target evaporation temperature to be too large. This leads to an upward adjustment of the frequency, increasing the cooling capacity of the already turned-on indoor unit and decreasing room temperature. Conversely, the target evaporation temperature may decrease after the newly turned-on indoor unit is activated, while the outlet superheat of the already turned-on indoor unit remains unchanged, resulting in an increase in the cooling capacity of the already turned-on indoor unit and a decrease in room temperature.

[0089] For example, in question two: it is difficult for multiple rooms to reach the set temperature.

[0090] The target evaporation temperature is a fixed value and is relatively low, which causes the cooling capacity of the indoor unit with low energy demand to be too large, resulting in the room temperature being lower than the set temperature; the target superheat of each indoor unit is the same and remains unchanged, which causes the cooling capacity of the indoor unit with low energy demand to be too large, resulting in the room temperature being lower than the set temperature.

[0091] For example, question 3: High energy consumption.

[0092] The compressor is controlled to achieve a lower evaporation temperature, which also reduces the suction pressure, resulting in lower suction density. To achieve the same refrigerant flow rate, the compressor must increase its operating frequency, thus increasing energy consumption. Secondly, as the room temperature decreases or increases, the indoor unit's capacity requirement decreases or increases, causing compressor frequency fluctuations and further increasing energy consumption.

[0093] Based on this, the present invention provides a control method. Upon receiving an indoor unit start command, the method determines a target indoor unit from among the already started indoor units and the indoor units to be started corresponding to the start command, wherein the target indoor unit's target capacity requirement is greater than that of other indoor units besides the target indoor unit; determines the target evaporation temperature of the target indoor unit; and executes a preset operation, the preset operation including at least one of the following: adjusting the compressor operating frequency of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the already started indoor unit; adjusting the opening degree of the electronic expansion valve of the already started indoor unit according to the target superheat of the already started indoor unit; and controlling the electronic expansion valve of the indoor unit to be started to gradually open according to a preset number of steps.

[0094] In this way, once the indoor unit in a room with high energy demand is turned on, the room temperature fluctuation is minimal. The electronic expansion valve of the newly turned-on indoor unit does not open directly to its initial opening, but rather gradually increases in size. This prevents a sudden decrease in refrigerant flow to the already turned-on indoor unit, resulting in more stable cooling capacity and less room temperature fluctuation. Furthermore, the compressor frequency is adjusted based on the difference between the actual evaporating temperature and the target evaporating temperature of the already turned-on indoor unit, avoiding the inclusion of the higher actual evaporating temperature of the newly turned-on indoor unit in the calculation. This prevents significant frequency changes, ensuring more stable cooling capacity and less room temperature fluctuation. Finally, the target evaporating temperature is determined based on the highest capacity demand among multiple rooms, while the lower capacity demands of other rooms are met by increasing the superheat. This ensures more stable cooling capacity and less room temperature fluctuation in the already heated rooms.

[0095] Furthermore, multiple rooms can reach the set temperature. The target evaporation temperature is determined based on the maximum capacity demand among the multiple rooms. This ensures that the cooling capacity of the indoor unit in the room with the maximum capacity demand always matches the room's cooling load, resulting in high temperature control accuracy. The smaller capacity demands of other rooms are met by increasing the superheat, ensuring that the cooling capacity provided by the indoor unit always approaches the room's capacity demand until a match is achieved, thus also achieving high temperature control accuracy.

[0096] Furthermore, the embodiments of this application exhibit low energy consumption. The target evaporation temperature increases as the maximum capacity requirement decreases, implying an increase in evaporation pressure, which in turn increases suction pressure and suction density. Since refrigerant flow rate is positively correlated with suction density, the frequency can be appropriately reduced while maintaining the same refrigerant flow rate, thus decreasing energy consumption accordingly. With minimal fluctuations in room temperature, the compressor frequency and system state do not change significantly, resulting in relatively stable energy consumption.

[0097] To better understand the above technical solutions, exemplary embodiments of this disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0098] As one implementation method, the hardware environment architecture involved in the control method of the multi-split air conditioner can be as follows: Figure 1 As shown.

[0099] Optionally, the hardware architecture involved in the control method for a multi-split air conditioner may include a terminal, such as a mobile terminal or a central control device for the multi-split air conditioner, such as a large screen or other terminal with a display interface, which is used to control the multi-split air conditioner. Alternatively, the terminal may be the multi-split air conditioner itself.

[0100] In one implementation, the terminal includes: a processor 101, such as a CPU, a memory 102, and a communication bus 103. The communication bus 103 is used to establish communication between these components. The processor 102 is used to invoke an application program to perform control operations.

[0101] The memory 102 can be a high-speed RAM or a stable memory (non-volatile memory), such as a disk storage device.

[0102] It is understood that, in one embodiment, the control program that implements the control process of the multi-split air conditioner is stored in the memory 102 of the multi-split air conditioner, or in the memory 102 of the terminal. When the processor 101 calls the control program from the memory 102, it performs the following operations:

[0103] Receive an indoor unit start command, determine a target indoor unit from the already started indoor units and the indoor units to be started corresponding to the indoor unit start command, and the target capacity requirement of the target indoor unit is greater than that of other indoor units except the target indoor unit;

[0104] Determine the target evaporation temperature of the target indoor unit;

[0105] Perform a preset operation, which includes at least one of the following:

[0106] The compressor operating frequency of the multi-split air conditioner is adjusted according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on;

[0107] Adjust the opening degree of the electronic expansion valve of the indoor unit that has been turned on according to the target superheat of the indoor unit that has been turned on;

[0108] The electronic expansion valve of the indoor unit to be turned on is gradually opened according to the preset number of steps.

[0109] Based on the hardware architecture of the multi-split air conditioner described above, the following embodiments of the present invention are proposed.

[0110] In the first embodiment, please refer to Figure 2 The control method for multi-split air conditioners proposed in this embodiment includes the following steps:

[0111] Step S10: Receive an indoor unit start command, determine a target indoor unit from the already started indoor units and the indoor units to be started corresponding to the indoor unit start command, the target indoor unit's target capacity requirement is greater than that of other indoor units besides the target indoor unit;

[0112] Step S20: Determine the target evaporation temperature of the target indoor unit;

[0113] Step S30: Perform a preset operation, which includes at least one of the following:

[0114] The compressor operating frequency of the multi-split air conditioner is adjusted according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on;

[0115] Adjust the opening degree of the electronic expansion valve of the indoor unit that has been turned on according to the target superheat of the indoor unit that has been turned on;

[0116] The electronic expansion valve of the indoor unit to be turned on is gradually opened according to the preset number of steps.

[0117] In this embodiment, the execution terminal can be a terminal that communicates with the multi-split air conditioner and enables the multi-split air conditioner to respond to control commands, such as a mobile terminal. It can also be the multi-split air conditioner itself. The following explanation uses an example of operation within a multi-split air conditioner:

[0118] The multi-split air conditioner includes one outdoor unit and at least two indoor units, all of which are connected to the outdoor unit. The indoor units can start simultaneously or at different times; for example, indoor unit A may start for a period of time or reach the set temperature before indoor unit B starts. In scenarios where the indoor units do not start simultaneously, the room temperature in the room containing the already started indoor unit will fluctuate significantly.

[0119] To avoid temperature fluctuations, in this embodiment, when an indoor unit start command is received, the already turned-on indoor unit is identified; when the already turned-on indoor unit is identified, the target indoor unit is determined from the already turned-on indoor unit and the indoor unit to be turned on corresponding to the indoor unit start command, and then a preset operation is performed to minimize the temperature fluctuation of the indoor environment where the already turned-on indoor unit is located.

[0120] The preset operation includes: adjusting the compressor operating frequency of the multi-split air conditioner according to the target evaporation temperature of the target indoor unit and the actual evaporation temperature of the already turned-on indoor unit. Based on the fact that the actual evaporation temperature of the already turned-on indoor unit has reached the set temperature, or is lower than the actual evaporation temperature of the indoor unit to be turned on, that is, the difference in target evaporation temperature is small, and the newly turned-on indoor unit with a higher temperature in the middle is not considered. In this way, the change range of the compressor operating frequency is small, so that the cooling capacity of the compressor is more stable, and the excessive cooling capacity is avoided from affecting the temperature of the room where the already turned-on indoor unit is located.

[0121] And / or, the preset operation includes: adjusting the opening of the electronic expansion valve of the indoor unit based on the target superheat of the indoor unit. The target superheat is adjusted in real time according to the target superheat of the indoor unit, so that the indoor ambient temperature of the indoor unit tends towards the set temperature, such that the difference is within a preset range. In this way, the cooling capacity provided by the indoor unit meets the indoor demand and can avoid temperature fluctuations in the room where the indoor unit is located.

[0122] And / or, the preset operation also includes: controlling the electronic expansion valve of the indoor unit to be turned on to gradually open according to a preset number of steps. The electronic expansion valve of the indoor unit to be turned on opens gradually from small to large, so that the refrigerant flow allocated to the indoor unit to be turned on is initially small and then gradually increases. This avoids a situation where a large amount of refrigerant is allocated to the indoor unit to be turned on when it is first turned on, causing a sudden decrease in the amount of refrigerant in the already turned-on indoor unit and resulting in a significant drop in temperature. This also ensures that the cooling capacity of the already turned-on indoor unit is relatively stable, and the room temperature fluctuations are small.

[0123] Optionally, in this embodiment, the step of determining the target evaporation temperature of the target indoor unit includes:

[0124] Determine the instantaneous capacity requirements of the target internal unit;

[0125] The target evaporation temperature of the target indoor unit is determined based on the instantaneous capacity requirement, the rated nominal capacity of the target indoor unit, the indoor ambient temperature where the target indoor unit is located, the outdoor ambient temperature, the first correction value, the second correction value, and the third correction value.

[0126] Optionally, the instantaneous capacity requirement of the target indoor unit is determined based on the current indoor ambient temperature and the current outdoor ambient temperature. The target evaporation temperature of the target indoor unit is determined based on the instantaneous capacity requirement, and then the compressor is adjusted based on the target evaporation temperature.

[0127] In one optional embodiment, the instantaneous capacity requirement is calculated according to the following formula:

[0128] Q req =Q load +Q sensible ;

[0129] Optionally, Q req This indicates the instantaneous capacity requirement of the target indoor unit, expressed in kW.

[0130] Q load This indicates the instantaneous cooling load of the target indoor unit, expressed in kW.

[0131] Q sensible This indicates the sensible heat load to be removed from the target indoor unit, in kW;

[0132] Optionally, Q load According to K wall K floor F wall F floor At least one of T0, T4 and T1 is determined.

[0133] Optionally, K wall The overall heat transfer coefficient of the wall is taken as 1.95 W / (m²). 2 .K);

[0134] K floor The overall heat transfer coefficient of the roof or roof floor is taken as 3.13 W / (m²). 2 .K);

[0135] F wall F represents the heat transfer area of ​​the wall. wall =L×H;

[0136] F floor F represents the heat transfer area of ​​the roof or roof floor. floor =L×L;

[0137] L represents the side length of the standard room (the floor is considered a square) corresponding to the indoor unit; for a 3-horsepower unit, the default L = 7m and H = 2.8m; for a 2-horsepower unit, the default L = 5.5m and H = 2.8m; and for a 1-horsepower unit, the default L = 4m and H = 2.8m.

[0138] T0 represents the initial room temperature when the target indoor unit is turned on, in °C;

[0139] T4 indicates the outdoor ambient temperature, in °C.

[0140] T1 represents the indoor ambient temperature of the target indoor unit, in °C.

[0141] Optionally, Q sensible The specific heat capacity Cp of the air in the standard room, the mass m of the air in the standard room corresponding to the target indoor unit, the indoor ambient temperature T1 of the target indoor unit, the set temperature Ts of the room where the target indoor unit is located, and the preset time constant τ are determined.

[0142] Optionally, m is in kg; Cp is 1.005 KJ / (kg·K); and τ is 100 s.

[0143] Optionally, after calculating the target instantaneous capacity requirement in the above manner, the target evaporation temperature of the target indoor unit is determined based on the target instantaneous capacity requirement.

[0144] Specifically, based on the instantaneous capability requirement Q req The rated nominal capacity Q of the target interior unit rated The target evaporation temperature of the target indoor unit is determined by the indoor ambient temperature T1, the outdoor ambient temperature T4, the first correction value k2, the second correction value K3, and the third correction value K5.

[0145] Optionally, k2 represents a real-time correction parameter for the target evaporation temperature, with a default value of 0;

[0146] K3 represents a temporary adjustment parameter for the target evaporation temperature, with a default value of 0;

[0147] K5 represents the pre-adjustment parameter for the target evaporation temperature, with a default value of 0;

[0148] Optionally, in some embodiments, the larger K2, K3, and K5 are, the higher the target evaporation temperature is.

[0149] Optionally, in some embodiments, the target evaporation temperature is determined based on coefficient a0 and the instantaneous capacity requirement Q, which is corrected based on a first coefficient a1 and a second coefficient a2. req and the rated nominal capacity Q of the target interior unit rated The target evaporation temperature is determined based on the indoor ambient temperature corrected by the third coefficient a3 and the fourth coefficient a4, the outdoor temperature corrected by the fifth coefficient a5, the first correction value k2, the second correction value K3, and the third correction value K5, making the target evaporation temperature more accurate. Optionally, a0-a5 are coefficients, and the values ​​of a0-a5 can be selected as [-5; 5].

[0150] In this embodiment, the target evaporation temperature of the target indoor unit is calculated using the above method, and then the operating frequency of the compressor is adjusted according to the target evaporation temperature and the actual evaporation temperature of the already turned-on indoor unit.

[0151] Optionally, in this embodiment, K5 is a preset adjustment parameter. K5 is calculated based on the instantaneous capacity requirement of the target indoor unit when the indoor ambient temperature reaches the set temperature, the rated nominal capacity of the target indoor unit, the set temperature of the target indoor unit, the outdoor ambient temperature, and the superheat correction parameter to obtain the target superheat. The value of K5 is determined by ensuring that the target superheat is greater than 1. If the calculated target superheat is greater than or equal to 1°C, then K5 is determined to be the value at that time; if it is less than 11°C, K5 is decreased by 1, and the target superheat is recalculated until the target superheat is greater than or equal to 1°C, at which point K5 is determined.

[0152] Optionally, in this embodiment, the target capacity requirement of the target indoor unit is greater than that of other indoor units. Therefore, the target indoor unit can be determined by the target capacity requirements of each indoor unit. Since target capacity requirements include both instantaneous capacity requirements and temperature-reaching capacity requirements, if the target indoor unit is determined by instantaneous capacity requirements, the instantaneous capacity requirements of each indoor unit can be directly calculated, and the indoor unit with the larger instantaneous capacity requirement can be selected as the target indoor unit. If the target indoor unit is determined by temperature-reaching capacity requirements, the following method can be used for determination:

[0153] Optionally, the step of determining the target indoor unit from the already powered-on indoor units and the indoor unit to be powered-on corresponding to the indoor unit power-on command includes:

[0154] The system obtains the first evaporation temperature at which the indoor ambient temperature of the already turned-on indoor unit reaches the set temperature, and the second evaporation temperature at which the indoor ambient temperature of the indoor unit to be turned on reaches the set temperature.

[0155] When the first evaporation temperature is less than or equal to the second evaporation temperature, the target indoor unit is determined to be the indoor unit that has been turned on.

[0156] When the first evaporation temperature is greater than the second evaporation temperature, the target indoor unit is determined to be the indoor unit to be turned on.

[0157] That is, by judging the target evaporation temperature of each indoor unit, the indoor unit with the lower target evaporation temperature is selected as the indoor unit with the greater target capacity requirement, and thus determined as the target indoor unit.

[0158] Optionally, in the preset operations described in this embodiment, adjusting the compressor operating frequency of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the already turned-on indoor unit; adjusting the opening degree of the electronic expansion valve of the already turned-on indoor unit according to the target superheat of the already turned-on indoor unit; and controlling the electronic expansion valve of the indoor unit to be turned on to gradually open according to a preset number of steps can be performed simultaneously. Alternatively, they can be performed sequentially. Or, after performing one of the operations, other operations can be selected to be performed based on the indoor ambient temperature fluctuations of the currently turned-on indoor unit and the indoor ambient temperature fluctuations of the indoor unit to be turned on.

[0159] Optionally, in this embodiment, the calculation method for the first and second reaching evaporation temperatures is the same as the calculation method for the target evaporation temperature described above. Optionally, when calculating the reaching evaporation temperature, the set temperature of the indoor unit is used to determine the corresponding reaching evaporation temperature when the set temperature is reached.

[0160] Alternatively, please refer to Figure 3 The step of adjusting the operating frequency of the compressor of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on includes:

[0161] Step S31: Obtain the first difference between the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on;

[0162] Step S32: Determine the target frequency parameter of the compressor based on the mapping relationship between the first difference and the compressor frequency parameter. The target frequency parameter includes a frequency adjustment value and an adjustment period.

[0163] Step S33: Adjust the operating frequency of the compressor according to the target frequency parameter.

[0164] Optionally, the compressor's operating frequency can be directly obtained based on the mapping relationship between the target evaporation temperature, the actual evaporation temperature, and the operating frequency. Alternatively, as described above, it can be obtained through a first difference between the target evaporation temperature and the actual evaporation temperature, and the mapping relationship between the first difference and the compressor frequency parameters. The mapping relationship between the first difference and the compressor frequency parameters is preset, and then after determining the first difference, the compressor's frequency parameters, such as the frequency adjustment value and operating cycle, are queried through this mapping relationship.

[0165] In this embodiment, the compressor operating frequency is adjusted based on the difference between the target evaporation temperature of the target indoor unit and the actual evaporation temperature of the already turned-on indoor unit. Since the actual evaporation temperature of the already turned-on indoor unit is close to its heat exchange requirements, regardless of whether the target indoor unit is already turned on or waiting to be turned on, the actual evaporation temperature is closer to the target evaporation temperature. Therefore, the compressor operating frequency only needs minor adjustments, avoiding significant changes and preventing excessive instantaneous cooling capacity from causing the indoor ambient temperature of the already turned-on indoor unit to be too low. Furthermore, since the compressor is adjusted based on the target evaporation temperature of the indoor unit with the highest capacity demand, the compressor's cooling capacity is adjusted according to the indoor unit with the greatest demand, thus ensuring the needs of all indoor units are met.

[0166] In an optional embodiment, to avoid compressor shutdown due to excessively low frequency after adjustment, this embodiment determines the target frequency parameter of the compressor based on the mapping relationship between the first difference and the compressor frequency parameter. Then, it determines whether the adjusted operating frequency is less than a preset frequency. If it is less, the preset frequency is used as the compressor's operating frequency to avoid excessively low frequency after adjustment. If it is greater than or equal to the preset frequency, the compressor is adjusted using the target frequency parameter. Optionally, the preset frequency is a low-pressure critical frequency, and optionally, the preset frequency is 15Hz.

[0167] Alternatively, please refer to Figure 4 The step of controlling the electronic expansion valve of the indoor unit to be turned on to gradually open according to a preset number of steps includes:

[0168] Step S34: At preset time intervals, control the electronic expansion valve of the indoor unit to be opened to open for the preset number of steps until the electronic expansion valve of the indoor unit to be opened is opened to the preset degree.

[0169] For example, starting from zero, increase the opening to 30 steps and hold for 180 seconds; increase the opening to 60 steps and hold for 180 seconds; increase the opening to 90 steps and hold for 180 seconds; increase the opening to 120 steps and hold for 180 seconds; increase the opening to 150 steps and hold for 180 seconds.

[0170] It is understood that the preset time interval is not limited to the aforementioned 180s, and the preset number of steps is not limited to 30 steps.

[0171] Optionally, in some embodiments, the preset number of steps may gradually increase or remain constant.

[0172] The indoor unit to be turned on has a high demand when it first starts up. However, the indoor unit has a cooling process when it starts up. During this process, by gradually opening the electronic expansion valve, the cooling capacity distributed to the indoor unit that has been turned on can be prevented from suddenly decreasing, thus avoiding room temperature fluctuations in the indoor unit that has been turned on. Since the compressor is adjusted according to the evaporation temperature of the indoor unit with high capacity demand, the energy demand of the indoor unit to be turned on can be met without affecting the temperature drop rate of the indoor unit to be turned on.

[0173] Optionally, the preset opening degree is the electronic expansion valve opening degree required to correspond to the set temperature of the indoor unit to be turned on.

[0174] Optionally, the control method for the multi-split air conditioner further includes:

[0175] Step S35: After the electronic expansion valve of the indoor unit to be turned on is opened to the preset opening degree, the adjustment parameters of the electronic expansion valve are determined according to the preset superheat of the indoor unit to be turned on.

[0176] Step S36: Adjust the electronic expansion valve according to the adjustment parameters.

[0177] That is, when the electronic expansion valve of the indoor unit to be turned on opens to a preset opening degree, the opening degree of the electronic expansion valve already meets the capacity requirements of the indoor unit to be turned on. At this time, the electronic expansion valve can maintain the preset opening degree. Alternatively, in a preferred embodiment, the electronic expansion valve is finely adjusted according to the superheat.

[0178] Optionally, in this embodiment, after the electronic expansion valve of the indoor unit to be turned on opens to the preset opening degree, the electronic expansion valve is adjusted according to the preset superheat degree of the indoor unit to be turned on. In one optional example, the preset superheat degree is 1.

[0179] Alternatively, please refer to Figure 5 The step of adjusting the opening degree of the electronic expansion valve of the already turned-on indoor unit according to the target superheat of the already turned-on indoor unit includes:

[0180] Step S37: Calculate the target superheat of the indoor unit based on the target evaporation temperature of the target indoor unit, the instantaneous capacity requirement of the indoor unit that has been turned on, the rated nominal capacity of the indoor unit that has been turned on, the indoor ambient temperature where the indoor unit that has been turned on is located, the outdoor ambient temperature, and the superheat correction parameters.

[0181] Step S38: Adjust the opening degree of the electronic expansion valve of the already opened indoor unit according to the target superheat.

[0182] Optionally, the electronic expansion valve of the already turned-on indoor unit is finely adjusted based on the target superheat, while a superheat correction parameter is used to correct the target superheat, ensuring that the already turned-on indoor unit can meet the capacity requirements. If the capacity requirements of the already turned-on indoor unit are lower than those of other indoor units, the target superheat is increased to ensure that the already turned-on indoor unit meets the requirements.

[0183] In some embodiments, a mapping relationship between the target superheat and the target evaporation temperature, instantaneous capacity requirement, rated nominal capacity, indoor ambient temperature, outdoor ambient temperature, and superheat correction parameters can be preset. After determining the target evaporation temperature, instantaneous capacity requirement, rated nominal capacity, indoor ambient temperature, outdoor ambient temperature, and superheat correction parameters, the target superheat is determined based on this mapping relationship.

[0184] Alternatively, in other embodiments, the target superheat T can be calculated based on a preset formula for superheat. sh，target Optionally, the parameters of the preset formula include the evaporation temperature T. 2，target Instantaneous capacity requirement of the indoor unit Q req Rated nominal capacity, indoor ambient temperature T1 of the indoor unit, outdoor ambient temperature T4, and superheat correction value K4.

[0185] Optionally, when calculating the target superheat of the indoor unit that has been turned on, T2,target is the evaporation temperature of the target indoor unit, Qreq is the instantaneous capacity requirement of the indoor unit that has been turned on, and T1 is the indoor ambient temperature of the indoor unit that has been turned on.

[0186] Optionally, the preset formula for superheat includes coefficients a0-a5. Optionally, the values ​​of a0-a5 can be selected as [-10; 10]. a0-a5 respectively correct the superheat, the evaporation temperature, the ratio of the instantaneous capacity requirement to the rated nominal capacity, the indoor ambient temperature, and the outdoor ambient temperature.

[0187] The target superheat calculated in this embodiment is closer to the actual environmental requirements, making the opening adjustment of the electronic expansion valve more precise.

[0188] Optionally, a mapping relationship between superheat and electronic expansion valve can be preset. After determining the target superheat, the adjustment parameters of the electronic expansion valve are obtained and determined based on the mapping relationship. The adjustment parameters include the opening adjustment value and the operating cycle. Then, the electronic expansion valve is adjusted according to the adjustment parameters.

[0189] Optionally, in other embodiments, the adjustment parameters of the electronic expansion valve are determined by the difference between the actual superheat of the activated indoor unit and the target evaporation temperature. Optionally, the actual superheat is determined based on the difference between the outlet temperature and the middle temperature of the heat exchanger in the activated indoor unit.

[0190] Optionally, after determining the difference, the adjustment parameters of the electronic expansion valve are obtained by looking up the following table:

[0191] Conditions (°C) Opening adjustment value Action cycle (s) Y≥4 +10 30 2≤Y＜4 +6 60 1≤Y＜2 +4 60 0≤Y＜1 +2 120 0 0 120 -1≤Y＜0 -2 120 Y<-1 -8 30

[0192] Where Y is the difference between the actual superheat and the target superheat.

[0193] This embodiment determines the adjustment value and adjustment cycle of the electronic expansion valve by the difference between the actual superheat of the already turned-on indoor unit and the target superheat, making the adjustment more accurate.

[0194] Optionally, in this embodiment, if the target indoor unit is an already turned-on indoor unit, if it is determined in advance whether the second correction value and the third correction value of the target evaporation temperature are within the range of the first correction value, then the preset superheat of the target indoor unit is used as the target superheat.

[0195] If the second correction value and the third correction value are not within the range of the first correction value, the target superheat of the target indoor unit is determined based on the target evaporation temperature determined according to the instantaneous capacity requirement of the target indoor unit.

[0196] Optionally, the preset superheat is 1.

[0197] Optionally, if the target indoor unit is the indoor unit to be turned on, the target evaporation temperature of the target indoor unit is determined based on the target evaporation temperature determined by the instantaneous capacity requirement of the target indoor unit. Optionally, when the target indoor unit is the indoor unit to be turned on, during the process of adjusting the electronic expansion valve of the already turned-on indoor unit, since the already turned-on indoor unit has reached the temperature, it is necessary to detect in real time or periodically whether the difference between the indoor ambient temperature of the already turned-on indoor unit and the set temperature is within a preset range. If it is, there is no need to adjust the second correction value of the target evaporation temperature. If it is not within the preset range, the adjustment amount of the electronic expansion valve is increased by adjusting the second correction value of the target superheat, thereby maintaining the indoor ambient temperature of the already turned-on indoor unit within the preset range.

[0198] In one embodiment, T1-Ts≥1 and Tsh, T sh，target If T1-Ts≤0 and T sh，target If the value is ≤15, then increase the second correction value K4 by 1 and return to redetermine the target evaporation temperature.

[0199] Second Embodiment

[0200] Please refer to Figure 6This embodiment is based on all the above embodiments. After the step of adjusting the operating frequency of the compressor according to the target frequency parameter, it further includes:

[0201] Step S40: Obtain the second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature;

[0202] Step S50: Determine whether the second difference is greater than or equal to the first preset temperature difference;

[0203] If so, that is, when the second difference is greater than or equal to the first preset temperature difference, then return to step S20.

[0204] If not, that is, when the second difference is less than the first preset temperature difference, step S60 is executed to obtain the rate of decrease of the indoor ambient temperature where the indoor unit to be turned on is located;

[0205] Step S70: Determine whether the descent rate is greater than or equal to a preset descent rate;

[0206] If so, that is, when the descent rate is greater than or equal to the preset descent rate, return to step S20.

[0207] If not, that is, when the rate of decrease is less than the preset rate of decrease, proceed to step 80, reduce the second correction value of the target evaporation temperature, and then return to step S20.

[0208] In this embodiment, after the compressor is adjusted according to the target frequency parameters for at least one cycle, the temperature of the target indoor unit and the temperature drop of the indoor unit to be turned on are detected in real time, so as to monitor abnormal situations such as system failures in a timely manner.

[0209] If the compressor is adjusted according to the target frequency parameter, after one cycle, it is determined whether the actual evaporation temperature of the target indoor unit has reached the target evaporation temperature, such as T2 and T. 2，target If the difference is less than the first preset temperature difference (e.g., 1), it means that the actual evaporation temperature has reached the target evaporation temperature. Adjusting the compressor according to the current target evaporation temperature is appropriate, and the target indoor unit's evaporation temperature has reached the requirement. The compressor's operating frequency can be adjusted according to the current adjustment method. For example, after the indoor ambient temperature changes, the indoor ambient temperature is updated and the target evaporation temperature is re-determined, and then the compressor is readjusted.

[0210] If not, it means that the ambient temperature has not yet reached the required evaporation temperature. In this case, return to recalculate the target evaporation temperature.

[0211] Optionally, when the actual evaporation temperature of the target indoor unit reaches the target evaporation temperature, it is also necessary to detect the temperature drop of the indoor unit to be turned on to determine whether there are any abnormalities such as system malfunctions, and to adjust the target evaporation temperature in a timely manner based on the abnormalities to avoid problems that do not meet comfort requirements. For example, regarding the rate of temperature drop of the indoor unit to be turned on, if the rate of drop reaches the preset rate of drop, it indicates that the indoor unit to be turned on is cooling normally (the temperature drop rate of the indoor unit to be turned on is relatively high during the cooling phase), that is, the compressor is operating normally and the indoor unit to be turned on is cooling normally. If the rate of drop does not reach the preset rate of drop, it indicates that the indoor unit to be turned on is malfunctioning, not cooling down, or that the evaporation temperature of the indoor unit to be turned on is too high, resulting in low cooling efficiency for the room. In this case, the second correction value K3 of the target evaporation temperature is reduced to lower the target evaporation temperature. Optionally, the preset rate of drop is 1 / 360 (dT1 / dt≥1 / 360).

[0212] Optionally, in one embodiment, the step of reducing the target evaporation temperature when the descent rate is less than the preset descent rate, and then returning to the step of determining the target evaporation temperature of the target indoor unit, includes:

[0213] When the rate of descent is less than the preset rate of descent, a second correction value for the target evaporation temperature is obtained;

[0214] When the second correction value is greater than the second correction threshold, after reducing the target evaporation temperature, return to the step of determining the target evaporation temperature of the target indoor unit;

[0215] If the second correction value is less than or equal to the second correction threshold, return directly to the step of determining the target evaporation temperature of the target indoor unit.

[0216] Optionally, the second correction threshold is -5.

[0217] In this embodiment, when the temperature drop rate is less than the preset temperature drop rate, it indicates that the temperature drop rate of the indoor unit to be turned on does not meet the requirements. At this time, it is necessary to adjust the target evaporation temperature to increase the temperature drop rate of the indoor unit to be turned on. During the adjustment of the target evaporation temperature, in order to avoid adjusting the target evaporation temperature too low, the second correction value of the target evaporation temperature is controlled to be greater than or equal to the second correction value, so as to improve the control accuracy of the target evaporation temperature.

[0218] Optionally, the target indoor unit can be either the indoor unit to be turned on or the indoor unit already turned on. That is, the indoor unit with high capacity requirements could be either the indoor unit to be turned on or the indoor unit already turned on. However, due to the different indoor ambient temperatures of the indoor unit to be turned on and the indoor unit already turned on, the opening degree of the electronic expansion valve will also be different. Furthermore, considering factors such as not affecting the indoor environment of the indoor unit already turned on, the requirements for the compressor operating frequency and the electronic expansion valve will differ during or after the execution of the preset operation, i.e., there are differences in control. Based on this, embodiments of the present invention set different control strategies for different types of indoor units, such as a first control strategy corresponding to when the target indoor unit is an already turned-on indoor unit and a second control strategy corresponding to when the target indoor unit is a indoor unit to be turned on. After determining the target indoor unit, a corresponding control strategy is determined based on the target indoor unit to control the multi-split air conditioner.

[0219] During some adjustments, the control methods for the compressor operating frequency, the opened indoor unit electronic expansion valve, and the unopened indoor unit electronic expansion valve are the same in both the first and second control strategies, as described in the control processes of the first and second embodiments above. That is, when it is determined that the first control strategy is used to control the multi-split air conditioner, the steps of each of the above embodiments are executed. Similarly, when it is determined that the second control strategy is used to control the multi-split air conditioner, the steps of each of the above embodiments are also executed.

[0220] Optionally, during some adjustments, the first control strategy and the second control strategy may differ in their control methods regarding the compressor operating frequency, the already opened electronic expansion valve of the indoor unit, and the electronic expansion valve of the indoor unit to be opened. As illustrated in the following embodiments, the descriptions will vary depending on the target indoor unit and the adjustment stage.

[0221] Third Embodiment

[0222] Please refer to Figure 7 This embodiment is based on all the above embodiments. Optionally, the preset operation further includes:

[0223] Step S101: When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature is obtained.

[0224] Step S102: Determine whether the second difference is less than the first preset temperature difference;

[0225] If not, return to step S20.

[0226] If so, proceed to step S103 to obtain the rate of change of the indoor ambient temperature where the target indoor unit is located;

[0227] Step S104: Determine whether the rate of change is less than the preset rate of change;

[0228] If not, return directly to step S20.

[0229] If so, then execute step S105 to obtain the fourth difference between the indoor ambient temperature and the set temperature of the target indoor unit;

[0230] Step S106: Determine whether the fourth difference is within the second preset temperature difference range;

[0231] If so, proceed to step S107, adjust the first correction value of the target evaporation temperature according to the fourth difference, and return to step S20.

[0232] If not, return directly to step S20.

[0233] Optionally, the first preset temperature difference range is a range where the indoor ambient temperature and the set temperature are close. Optionally, the first preset range can be between -2℃ and 2℃.

[0234] In this embodiment, if the third difference between the indoor ambient temperature of the unit to be turned on and the set temperature of the unit to be turned on is detected during the operation of the multi-split air conditioner within the first preset temperature difference range, it indicates that the room where the unit to be turned on has reached the set temperature, that is, the air conditioner is in the dual temperature-reaching stage of both the unit to be turned on and the unit that has been turned on.

[0235] During the dual-temperature-reaching phase, since both types of indoor units reach their designated temperatures, it is necessary to readjust the compressor's operating frequency.

[0236] In this embodiment, the compressor operating frequency is still adjusted based on the target evaporation temperature of the indoor unit. During the adjustment process, a second difference between the actual evaporation temperature of the indoor unit and the target evaporation temperature is detected in real time or periodically. If the second difference is less than the first preset temperature difference (e.g., less than 1), it indicates that adjusting the compressor based on the target evaporation temperature is highly accurate. If it is greater than the first preset temperature difference, it indicates that the target evaporation temperature is not accurate enough, and the process returns to re-determining the target evaporation temperature.

[0237] When the target evaporation temperature accuracy is high, the rate of change of the indoor ambient temperature where the target indoor unit is located is obtained. If the rate of change is less than the preset rate of change, it indicates that the current indoor ambient temperature fluctuation is small. At this time, a fourth difference between the indoor ambient temperature and the set temperature can be obtained. If the fourth difference is within the second preset temperature difference range, it indicates that the indoor temperature not only has small fluctuations but is also very close to the set temperature. At this time, the magnitude of the fourth difference determines whether the target evaporation temperature needs to be adjusted (by adjusting the first correction value of the target evaporation temperature). If the fourth difference is not within the second preset range, it indicates that the indoor temperature fluctuation is large. At this time, the target evaporation temperature needs to be recalculated to reduce the indoor temperature fluctuation.

[0238] Optionally, the preset rate of change is 1 / 600 (dT1 / dt is less than 1 / 600); the second preset temperature difference range is (-1, 1).

[0239] Optionally, the step of adjusting the first correction value of the target evaporation temperature based on the fourth temperature difference includes: when the fourth temperature difference is within a preset range, not adjusting the first correction value; if the fourth temperature difference is greater than or equal to the upper limit of the preset range, decreasing the first correction value to reduce the target evaporation temperature and reduce energy waste; if the fourth temperature difference is less than or equal to the lower limit of the preset range, increasing the first correction value to increase the target evaporation temperature, so that the indoor ambient temperature approaches the set temperature.

[0240] Optionally, in this embodiment, when the target indoor unit is an already turned-on indoor unit, since the indoor unit has reached its temperature and its capacity requirement is greater than that of the indoor unit to be turned on, the target evaporation temperature needs to be continuously adjusted using the second correction value of the above formula to ensure that the indoor unit to be turned on meets the capacity requirement. Therefore, when the target indoor unit is determined to be the already turned-on indoor unit, before each return to re-determine the target evaporation temperature of the target indoor unit, it is first determined whether the second correction value is zero. If it is, then there is no need to adjust the second correction value again. If it is not, it means that the target evaporation temperature has not yet reached the requirement, and the second correction value is increased to use the increased second correction value to adjust the target evaporation temperature of the target indoor unit. If the target indoor unit is determined to be the indoor unit to be turned on, since the already turned-on indoor unit has reached its temperature and the capacity requirement of the indoor unit to be turned on is greater, there is no need to adjust the target evaporation temperature of the target indoor unit again. Therefore, the second correction value is set to zero, and the second correction value is not used to adjust the target evaporation temperature to avoid repeated adjustments.

[0241] In other words, during the dual-temperature-reaching stage, the method for adjusting the compressor's operating frequency differs depending on whether the target indoor unit is already turned on or when it is yet to be turned on. This embodiment uses different methods to adjust the compressor based on the different operating conditions of the target indoor unit, making the adjusted compressor closer to the actual operating environment of the air conditioner and improving the accuracy of the adjustment.

[0242] Optionally, if the third difference between the indoor ambient temperature of the indoor unit to be turned on and the set temperature of the indoor unit to be turned on is not within the first preset temperature difference range, it indicates that the indoor unit to be turned on has not reached the temperature, and therefore the air conditioner continues to perform the control described in the first embodiment and / or the second embodiment.

[0243] Fourth embodiment

[0244] Please refer to Figure 8 This embodiment is based on all the above embodiments. Optionally, the preset operation further includes:

[0245] Step S106: When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, and the target indoor unit is the indoor unit to be turned on, obtain the second correction value and the third correction value.

[0246] Step S107: When the second correction value and the third correction value are within the range of the first correction value, the opening degree of the electronic expansion valve of the already opened indoor unit is adjusted using the preset superheat of the target indoor unit.

[0247] Step S108: When the second correction value and the third correction value are not within the range of the first correction value, determine the target superheat of the target indoor unit based on the target evaporation temperature determined by the instantaneous capacity requirement of the target indoor unit, and adjust the opening of the electronic expansion valve of the target indoor unit according to the target superheat.

[0248] In this embodiment, if the third difference between the indoor ambient temperature of the unit to be turned on and the set temperature of the unit to be turned on is detected during the operation of the multi-split air conditioner within the first preset temperature difference range, it indicates that the room where the unit to be turned on has reached the set temperature, that is, the air conditioner is in the dual temperature-reaching stage of both the unit to be turned on and the unit that has been turned on.

[0249] During the dual-temperature stage, since both types of indoor units reach the required temperature, it is necessary to readjust the opening of the electronic expansion valve of each indoor unit.

[0250] Optionally, the first preset temperature difference range is a range where the indoor ambient temperature and the set temperature are close. Optionally, the first preset range can be between -2℃ and 2℃.

[0251] The second and third correction values ​​are K3 and K5 in the formula for calculating the target evaporation temperature. Optionally, the first correction value range is the value that has the least impact on the target evaporation temperature from the second and third correction values; for example, in an optional embodiment, the first correction value range is 0. Optionally, the preset superheat is 1.

[0252] If the second and third correction values ​​are already 0, then the target superheat of the target indoor unit is determined based on the target evaporation temperature determined by the instantaneous capacity requirement of the target indoor unit, and the opening of the electronic expansion valve of the target indoor unit is adjusted according to the target superheat. If the second and third correction values ​​are not zero, then a preset superheat is used as the target superheat of the target indoor unit, and the opening of the electronic expansion valve is adjusted based on the target superheat.

[0253] If the target indoor unit is already turned on, the opening of the electronic expansion valve of the already turned-on indoor unit is adjusted in the manner described above. If the target indoor unit is to be turned on, the opening of the electronic expansion valve of the indoor unit to be turned on is adjusted in the manner described above.

[0254] Optionally, in some embodiments, the above is based on adjustments made to indoor units with high capacity requirements. That is, during the dual-temperature stage, once all indoor units have reached their designated temperatures, the target evaporation temperature of the indoor unit with high capacity requirements is adjusted to ensure that the target evaporation temperature is within a suitable range, thus avoiding excessive cooling distribution to the target indoor unit and preventing the indoor ambient temperature where the target indoor unit is located from becoming too low.

[0255] Fifth embodiment

[0256] Please refer to Figure 9 This embodiment is based on all the above embodiments. Optionally, the preset operation further includes:

[0257] Step S109: When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the target evaporation temperature is determined according to the instantaneous capacity requirements of other indoor units besides the target indoor unit.

[0258] Step S110: Determine the target superheat of the other indoor units based on the target evaporation temperature, and adjust the opening of the electronic expansion valve of the other indoor units according to the target superheat.

[0259] In this embodiment, if the third difference between the indoor ambient temperature of the unit to be turned on and the set temperature of the unit to be turned on is detected during the operation of the multi-split air conditioner within the first preset temperature difference range, it indicates that the room where the unit to be turned on has reached the set temperature, that is, the air conditioner is in the dual temperature-reaching stage of both the unit to be turned on and the unit that has been turned on.

[0260] During the dual-temperature stage, since both types of indoor units reach the required temperature, it is necessary to readjust the opening of the electronic expansion valve of each indoor unit.

[0261] During the dual-temperature-reaching phase, the compressor operates at a stable frequency, thus the cooling capacity does not change significantly. Since the other indoor units besides the target unit have low capacity requirements, their electronic expansion valves can be fine-tuned based on their own target superheat to maintain the indoor ambient temperature.

[0262] If the target indoor unit is already turned on, the opening degree of the electronic expansion valve of the indoor unit to be turned on is determined using the above method. If the target indoor unit is an indoor unit to be turned on, the opening degree of the electronic expansion valve of the already turned-on indoor unit is determined using the above method.

[0263] Optionally, in some embodiments, the above is based on adjustments made to indoor units with low capacity requirements. For indoor units with low capacity requirements, after all indoor units have reached their operating temperature, it is necessary to increase the superheat to ensure that the cooling capacity of the indoor unit meets the capacity requirements.

[0264] The preset operation further includes: obtaining the ambient temperature of the other indoor unit and the set temperature of the other indoor unit; determining whether the fifth difference between the ambient temperature and the set temperature is greater than the second preset difference; when the fifth difference is greater than the second preset temperature difference and the target superheat of the other indoor unit is greater than the preset threshold, reducing the correction parameter of the target superheat of the other indoor unit and returning to the step of determining the target evaporation temperature based on the instantaneous capacity requirement of the other indoor unit besides the target indoor unit; when the fifth difference is less than the second preset temperature difference and the target superheat of the other indoor unit is less than the preset threshold, increasing the correction parameter of the target superheat of the other indoor unit and returning to the step of determining the target evaporation temperature based on the instantaneous capacity requirement of the other indoor unit besides the target indoor unit.

[0265] In other words, by measuring the difference between the ambient temperature and the set temperature, the system determines how much the indoor ambient temperature differs from the set temperature for the other indoor units. If the indoor ambient temperature is higher than the set temperature, the target superheat correction parameter is reduced to increase the superheat, thereby increasing the heat exchange capacity of the indoor units with lower capacity requirements and thus lowering the indoor ambient temperature. If the indoor ambient temperature is lower than the set temperature, the target superheat correction parameter is increased to reduce the superheat and minimize the loss of cooling capacity.

[0266] Sixth Embodiment

[0267] This embodiment is based on all the above embodiments. Optionally, the preset operation further includes:

[0268] Adjust the speed of the indoor unit fan according to the adjusted operating frequency of the compressor.

[0269] In this embodiment, the indoor unit fan includes a fan for an indoor unit that has been turned on and a fan for an indoor unit that is to be turned on.

[0270] Regardless of whether the target indoor unit is already turned on or waiting to be turned on, the speed of the indoor unit's fan is adjusted in conjunction with the operating frequency of the compressor. Furthermore, the control of the indoor unit's fan adjusts along with the compressor's operating frequency during both the cooling and temperature-reaching stages of the indoor unit waiting to be turned on. This linkage control with the operating frequency results in better heat exchange performance for the indoor unit.

[0271] Optionally, the linkage between the rotational speed and operating frequency of the indoor unit fan includes, but is not limited to, the following methods:

[0272] The fan includes airflow return parameters and airflow control parameters. These parameters correspond to different operating frequencies. For example, when the compressor's operating frequency is less than or equal to the preset frequency, the indoor unit fan is adjusted using the airflow return parameters. When the compressor's operating frequency is greater than the preset frequency, the indoor unit fan is adjusted using the airflow control parameters. The preset frequency is the low-pressure critical frequency, optionally 15Hz.

[0273] Optionally, the air supply volume return parameters are shown in the table below:

[0274]

[0275] Optionally, the air supply volume control parameters are shown in the table below:

[0276]

[0277] Optionally, the air supply volume control parameters are determined based on the indoor ambient temperature, the set temperature, and the rate of decrease of the indoor temperature (or the rate of change of the indoor ambient temperature).

[0278] Optionally, in the above embodiments, examples are used to more clearly illustrate the various embodiments of the present invention. The following description uses different control strategies without a control process as examples.

[0279] For example, the first control strategy, taking the already turned-on indoor unit as an example, is divided into a cooling stage and a temperature-reaching stage:

[0280] During the cooling phase, when adjusting the operating frequency of the compressor of the multi-split air conditioner based on the target evaporation temperature and the actual evaporation temperature of the already turned-on indoor unit, after one adjustment cycle, a second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature is obtained. When the second difference is less than the first preset temperature difference, the rate of decrease of the indoor ambient temperature where the indoor unit to be turned on is located is obtained. When the rate of decrease is less than the preset rate of decrease, the second correction value of the target evaporation temperature is reduced, and the process returns to redetermine the target evaporation temperature of the target indoor unit.

[0281] If the rate of descent is greater than the preset rate of descent, then return directly to continue determining the target evaporation temperature for the next round.

[0282] During the temperature reaching stage, specifically when the third difference between the indoor ambient temperature where the indoor unit to be turned on and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, a second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature is obtained. When the second difference is less than the first preset temperature difference, the rate of change of the indoor ambient temperature where the target indoor unit is located is obtained. When the rate of change is less than the preset rate of change, a fourth difference between the indoor ambient temperature where the target indoor unit is located and the set temperature is obtained. When the fourth difference is outside the second preset temperature difference range, the first correction value of the target evaporation temperature is adjusted according to the fourth difference, and the process returns to determine the target evaporation temperature of the target indoor unit. Specifically, during the process of returning to re-determine the evaporation temperature of the target indoor unit, it is first determined whether the second correction value of the target evaporation temperature is 0. If not, the second correction value is increased, and the increased second correction value is used to correct the target evaporation temperature of the target indoor unit.

[0283] During the cooling phase, the electronic expansion valve of the indoor unit to be turned on should be adjusted as follows:

[0284] The electronic expansion valve of the indoor unit to be opened is gradually opened according to a preset number of steps. For example, the electronic expansion valve of the indoor unit to be opened is opened for the preset number of steps at preset time intervals until the electronic expansion valve of the indoor unit to be opened is opened to the preset degree.

[0285] During the temperature-reaching stage, when the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the electronic expansion valve of the indoor unit to be turned on is adjusted in the following manner:

[0286] The target evaporation temperature is determined based on the instantaneous capacity requirement of the indoor unit to be turned on;

[0287] The target superheat of the indoor unit to be turned on is determined based on the target evaporation temperature, and the opening degree of the electronic expansion valve of the indoor unit to be turned on is adjusted according to the target superheat.

[0288] Before determining the target evaporation temperature, the sixth difference between the indoor ambient temperature of the indoor unit to be turned on and its set temperature is first obtained. When the sixth difference is greater than the second preset temperature difference and the target superheat of the indoor unit to be turned on is greater than a preset threshold, the correction parameter for the target superheat of the indoor unit to be turned on is reduced, and then the target evaporation temperature is determined based on the instantaneous capacity requirement of the indoor unit to be turned on. When the sixth difference is less than the second preset temperature difference and the target superheat of the indoor unit to be turned on is less than the preset threshold, the correction parameter for the target superheat of the indoor unit to be turned on is increased, and then the target evaporation temperature is determined based on the instantaneous capacity requirement of the indoor unit to be turned on.

[0289] During the cooling phase, the electronic expansion valve of the indoor unit, which has been turned on, should be adjusted as follows:

[0290] The target superheat of the indoor unit is calculated based on the target evaporation temperature of the target indoor unit, the instantaneous capacity requirement of the indoor unit that has been turned on, the rated nominal capacity of the indoor unit that has been turned on, the indoor ambient temperature where the indoor unit that has been turned on is located, the outdoor ambient temperature, and the superheat correction parameters.

[0291] Adjust the opening degree of the electronic expansion valve of the already opened indoor unit according to the target superheat.

[0292] Before calculating the target evaporation temperature, a second correction value and a third correction value for the target evaporation temperature are first obtained. When the second and third correction values ​​are within the range of the first correction value, the preset superheat of the target indoor unit is used as the target superheat, and then the electronic expansion valve of the already turned-on indoor unit is adjusted according to the target superheat. The target superheat is 1. When the second and third correction values ​​are outside the range of the first correction value, the target superheat of the already turned-on indoor unit is directly calculated based on the target evaporation temperature of the target indoor unit, the instantaneous capacity requirement of the already turned-on indoor unit, the rated nominal capacity of the already turned-on indoor unit, the indoor ambient temperature where the already turned-on indoor unit is located, the outdoor ambient temperature, and the superheat correction parameters.

[0293] During the temperature-reaching stage, the adjustment method of the electronic expansion valve of the indoor unit that has been turned on is the same as that during the cooling stage.

[0294] For example, the second control strategy, taking the indoor unit to be turned on as an example, is divided into a cooling stage and a temperature-reaching stage:

[0295] During the cooling phase, when adjusting the operating frequency of the compressor of the multi-split air conditioner based on the target evaporation temperature and the actual evaporation temperature of the already turned-on indoor unit, after one adjustment cycle, a second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature is obtained. When the second difference is less than the first preset temperature difference, the rate of decrease of the indoor ambient temperature where the indoor unit to be turned on is located is obtained. When the rate of decrease is less than the preset rate of decrease, the second correction value of the target evaporation temperature is reduced, and the process returns to redetermine the target evaporation temperature of the target indoor unit.

[0296] If the rate of descent is greater than the preset rate of descent, then return directly to continue determining the target evaporation temperature for the next round.

[0297] During the temperature reaching stage, specifically when the third difference between the indoor ambient temperature where the indoor unit to be turned on and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, a second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature is obtained. When the second difference is less than the first preset temperature difference, the rate of change of the indoor ambient temperature where the target indoor unit is located is obtained. When the rate of change is less than the preset rate of change, a fourth difference between the indoor ambient temperature where the target indoor unit is located and the set temperature is obtained. When the fourth difference is outside the second preset temperature difference range, the first correction value of the target evaporation temperature is adjusted according to the fourth difference, and then the system returns to determine the target evaporation temperature of the target indoor unit. Specifically, during the process of returning to re-determine the evaporation temperature of the target indoor unit, the system directly sets whether the second correction value of the target evaporation temperature is 0, and then returns to recalculate the target evaporation temperature.

[0298] During the cooling phase, the electronic expansion valve of the indoor unit to be turned on should be adjusted as follows:

[0299] The electronic expansion valve of the indoor unit to be opened is gradually opened according to a preset number of steps. For example, the electronic expansion valve of the indoor unit to be opened is opened for the preset number of steps at preset time intervals until the electronic expansion valve of the indoor unit to be opened is opened to the preset degree.

[0300] During the temperature-reaching stage, when the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the electronic expansion valve of the indoor unit to be turned on is adjusted in the following manner:

[0301] The target evaporation temperature is determined based on the instantaneous capacity requirement of the indoor unit to be turned on;

[0302] The target superheat of the indoor unit to be turned on is determined based on the target evaporation temperature, and the opening degree of the electronic expansion valve of the indoor unit to be turned on is adjusted according to the target superheat.

[0303] During the cooling phase, the electronic expansion valve of the indoor unit, which has been turned on, should be adjusted as follows:

[0304] The target superheat of the indoor unit is calculated based on the target evaporation temperature of the target indoor unit, the instantaneous capacity requirement of the indoor unit that has been turned on, the rated nominal capacity of the indoor unit that has been turned on, the indoor ambient temperature where the indoor unit that has been turned on is located, the outdoor ambient temperature, and the superheat correction parameters.

[0305] Adjust the opening degree of the electronic expansion valve of the already opened indoor unit according to the target superheat.

[0306] During the temperature-reaching stage, the adjustment method of the electronic expansion valve of the indoor unit that has been turned on is the same as that during the cooling stage.

[0307] It is understood that the above embodiments are described in the context of air conditioning cooling operation. Optionally, the above embodiments can also be operated in heating mode.

[0308] Optionally, embodiments of this application also provide a computer program product, the computer program product including control program code, which, when executed by a processor of a computer or other device, implements the above embodiments.

[0309] It should be noted that the above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A control method for a multi-split air conditioner, characterized in that, The control method for the multi-split air conditioner includes the following steps: Receive an indoor unit start command, determine a target indoor unit from the already started indoor units and the indoor units to be started corresponding to the indoor unit start command, and the target capacity requirement of the target indoor unit is greater than that of other indoor units except the target indoor unit; Determine the target evaporation temperature of the target indoor unit; Perform a preset operation, which includes at least one of the following: The compressor operating frequency of the multi-split air conditioner is adjusted according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on; Adjust the opening degree of the electronic expansion valve of the indoor unit that has been turned on according to the target superheat of the indoor unit that has been turned on; The electronic expansion valve of the indoor unit to be turned on is gradually opened according to the preset number of steps; The preset operation also includes: When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature is obtained. When the second difference is less than the first preset temperature difference, the rate of change of the indoor ambient temperature where the target indoor unit is located is obtained; When the rate of change is less than the preset rate of change, a fourth difference between the indoor ambient temperature where the target indoor unit is located and the set temperature is obtained; When the fourth difference is outside the second preset temperature difference range, the first correction value of the target evaporation temperature is adjusted according to the fourth difference, and the process returns to the step of determining the target evaporation temperature of the target indoor unit.

2. The control method for a multi-split air conditioner as described in claim 1, characterized in that, The step of determining the target indoor unit from the already powered indoor units and the indoor unit to be powered on corresponding to the indoor unit power-on command includes: The first temperature-reaching evaporation temperature corresponding to when the indoor ambient temperature of the indoor unit that is already turned on reaches the set temperature, and the second temperature-reaching evaporation temperature corresponding to when the indoor ambient temperature of the indoor unit that is to be turned on reaches the set temperature are obtained. When the first temperature reached by evaporation is less than or equal to the second temperature reached by evaporation, the target indoor unit is determined to be the indoor unit that has been turned on. When the first evaporation temperature is greater than the second evaporation temperature, the target indoor unit is determined to be the indoor unit to be turned on.

3. The control method for a multi-split air conditioner as described in claim 1, characterized in that, The step of determining the target evaporation temperature of the target indoor unit includes: Determine the instantaneous capacity requirements of the target internal unit; The target evaporation temperature of the target indoor unit is determined based on the instantaneous capacity requirement, the rated nominal capacity of the target indoor unit, the indoor ambient temperature where the target indoor unit is located, the outdoor ambient temperature, the first correction value, the second correction value, and the third correction value.

4. The control method for a multi-split air conditioner as described in claim 1, characterized in that, The step of adjusting the operating frequency of the compressor of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on includes: Obtain the first difference between the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on; The target frequency parameter of the compressor is determined based on the mapping relationship between the first difference and the compressor frequency parameter. The target frequency parameter includes a frequency adjustment value and an adjustment period. Adjust the operating frequency of the compressor according to the target frequency parameters.

5. The control method for a multi-split air conditioner as described in claim 1, characterized in that, After the step of adjusting the compressor operating frequency of the multi-split air conditioner according to the target evaporation temperature and the actual evaporation temperature of the indoor unit that has been turned on, the method further includes: Obtain a second difference between the actual evaporation temperature of the target indoor unit and the target evaporation temperature; When the second difference is less than the first preset temperature difference, the rate of decrease of the indoor ambient temperature where the indoor unit to be turned on is located is obtained; When the rate of decrease is less than the preset rate of decrease, the second correction value of the target evaporation temperature is reduced, and the process returns to the step of determining the target evaporation temperature of the target indoor unit.

6. The control method for a multi-split air conditioner as described in claim 5, characterized in that, The step of reducing the target evaporation temperature when the descent rate is less than the preset descent rate, and then returning to the step of determining the target evaporation temperature of the indoor unit, includes: When the rate of descent is less than the preset rate of descent, a second correction value for the target evaporation temperature is obtained; When the second correction value is greater than the second correction threshold, the second correction value of the target evaporation temperature is reduced, and the process returns to the step of determining the target evaporation temperature of the target indoor unit. If the second correction value is less than or equal to the second correction threshold, return directly to the step of determining the target evaporation temperature of the target indoor unit.

7. The control method for a multi-split air conditioner as described in claim 1, characterized in that, The step of gradually opening the electronic expansion valve of the indoor unit to be turned on according to a preset number of steps includes: At preset time intervals, the electronic expansion valve of the indoor unit to be opened is controlled to open for a preset number of steps until the electronic expansion valve of the indoor unit to be opened is opened to a preset degree.

8. The control method for a multi-split air conditioner as described in claim 7, characterized in that, The method further includes: After the electronic expansion valve of the indoor unit to be turned on is opened to the preset opening degree, the adjustment parameters of the electronic expansion valve are determined according to the preset superheat of the indoor unit to be turned on. Adjust the electronic expansion valve according to the adjustment parameters.

9. The control method for a multi-split air conditioner as described in claim 1, characterized in that, The step of adjusting the opening degree of the electronic expansion valve of the already turned-on indoor unit according to the target superheat of the already turned-on indoor unit includes: The target superheat of the indoor unit is calculated based on the target evaporation temperature of the target indoor unit, the instantaneous capacity requirement of the indoor unit that has been turned on, the rated nominal capacity of the indoor unit that has been turned on, the indoor ambient temperature where the indoor unit that has been turned on is located, the outdoor ambient temperature, and the superheat correction parameters. Adjust the opening degree of the electronic expansion valve of the already opened indoor unit according to the target superheat.

10. The control method for a multi-split air conditioner as described in claim 1, characterized in that, Before the step of determining the target evaporation temperature of the target indoor unit, the method further includes: When the target indoor unit is determined to be the already turned-on indoor unit, the second correction value of the target evaporation temperature is increased, so that the target evaporation temperature of the target indoor unit is corrected using the increased second correction value; When the target indoor unit is determined to be the indoor unit to be turned on, the second correction value is set to zero.

11. The control method for a multi-split air conditioner as described in any one of claims 1 to 9, characterized in that, The preset operation also includes: When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, and the target indoor unit is the indoor unit to be turned on, a second correction value and a third correction value are obtained. When the second and third correction values ​​are within the range of the first correction value, the opening degree of the electronic expansion valve of the already opened indoor unit is adjusted using the preset superheat of the target indoor unit. When the second and third correction values ​​are outside the range of the first correction value, the target superheat of the target indoor unit is determined based on the target evaporation temperature determined according to the instantaneous capacity requirement of the target indoor unit, and the opening of the electronic expansion valve of the target indoor unit is adjusted according to the target superheat.

12. The control method for a multi-split air conditioner as described in any one of claims 1 to 9, characterized in that, The preset operation also includes: When the third difference between the indoor ambient temperature where the indoor unit to be turned on is located and the set temperature of the indoor unit to be turned on is within the first preset temperature difference range, the target evaporation temperature is determined based on the instantaneous capacity requirements of other indoor units besides the target indoor unit. The target superheat of the other indoor units is determined based on the target evaporation temperature, and the opening of the electronic expansion valve of the other indoor units is adjusted according to the target superheat.

13. The control method for a multi-split air conditioner as described in claim 12, characterized in that, The preset operation also includes: Obtain the fifth difference between the ambient temperature of the other indoor unit and the corresponding set temperature of the other indoor unit; When the fifth difference is greater than the second preset temperature difference and the target superheat of the other indoor unit is greater than the preset threshold, after reducing the correction parameter of the target superheat of the other indoor unit, the process returns to the step of determining the target evaporation temperature based on the instantaneous capacity requirements of the other indoor units besides the target indoor unit. When the fifth difference is less than the second preset temperature difference and the target superheat of the other indoor unit is less than the preset threshold, after increasing the correction parameter of the target superheat of the other indoor unit, the process returns to the step of determining the target evaporation temperature based on the instantaneous capacity requirements of the other indoor units besides the target indoor unit.

14. The control method for a multi-split air conditioner as described in claim 1, characterized in that, The preset operation also includes: Adjust the speed of the indoor unit fan according to the adjusted operating frequency of the compressor.

15. A multi-split air conditioner, characterized in that, The multi-split air conditioner includes a memory, a processor, and a control program stored in the memory and executable on the processor. When executed by the processor, the control program implements the steps of the control method for the multi-split air conditioner as described in any one of claims 1 to 14.

16. A storage medium, characterized in that, The storage medium stores a control program, which, when executed by a processor, implements the various steps of the control method for a multi-split air conditioner as described in any one of claims 1 to 14.

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