CONTROL METHOD FOR MULTI-SPLIT AIR-CONDITIONING SYSTEM, CONTROLLER, AIR-CONDITIONING SYSTEM, AND MEDIUM

Abstract

A control method includes determining an actual capacity requirement and a target evaporation temperature of each indoor unit of a multi-split air conditioning system, calculating a total capacity requirement of an outdoor unit of the multi-split air conditioning system according to the actual capacity requirements of the indoor units, and determining an initial frequency of a compressor of the outdoor unit according to the total capacity requirement, and adjusting a frequency of the compressor based on the initial frequency, and according to temperature characteristic values of evaporator coils of all the plurality of indoor units and a reference evaporation temperature if all the indoor units operate in an air blowing mode or according to the temperature characteristic values and a preset evaporation temperature threshold if not all the indoor units operate in the air blowing mode.

Claims

1.-13. (canceled)

14. A method for controlling a multi-split air conditioning system comprising: determining an actual capacity requirement and a target evaporation temperature of each of a plurality of indoor units of the multi-split air conditioning system; calculating a total capacity requirement of an outdoor unit of the multi-split air conditioning system according to the actual capacity requirements of the plurality of indoor units; determining an initial frequency of a compressor according to the total capacity requirement; in response to all the plurality of indoor units operating in an air blowing mode: determining the target evaporation temperature corresponding to an indoor unit having a lowest dew point temperature as a reference evaporation temperature; and adjusting a frequency of the compressor based on the initial frequency and according to temperature characteristic values of evaporator coils of all the plurality of indoor units and the reference evaporation temperature; and in response to not all the plurality of indoor units operating in the air blowing mode, adjusting the frequency of the compressor based on the initial frequency and according to the temperature characteristic values of the evaporator coils of all the plurality of indoor units and a preset evaporation temperature threshold.

15. The method of claim 14, wherein for each indoor unit, the actual capacity requirement is determined according to a required refrigeration capacity value, a rated cooling capacity, a fan speed, and an operation mode of the indoor unit, the required refrigeration capacity value is determined according to an indoor temperature and a set temperature corresponding to the indoor unit, and the operation mode is the air blowing mode or a regular cooling mode.

16. The method of claim 14, wherein for each indoor unit, the target evaporation temperature is determined according to a dew point temperature of the indoor unit, a heat transfer temperature difference correction parameter, and a mode correction parameter corresponding to the air blowing mode, and the dew point temperature is determined according to an indoor humidity and an indoor temperature that correspond to the indoor unit.

17. The method of claim 14, wherein determining the initial frequency includes: rounding the total capacity requirement as a frequency level of the compressor; and determining a frequency value corresponding to the frequency level as the initial frequency.

18. The method of claim 17, wherein determining the frequency value corresponding to the frequency level as the initial frequency includes: dividing a frequency range from a maximum frequency value to a minimum frequency value of the compressor into a plurality of frequency levels according to a preset frequency interval; and calculating the initial frequency according to the result of the rounding, the preset frequency interval, and the minimum frequency value.

19. The method of claim 14, wherein the air blowing mode includes a breezeless mode, a gentle breeze mode, or an anti-direct blowing mode; the method further comprising, for one indoor unit of the plurality of indoor units: during acquisition of the actual capability requirement of the one indoor unit, receiving a mode flag bit sent by the one indoor unit, the mode flag bit indicating to turn on the breezeless mode, the gentle breeze mode, or the anti-direct blowing mode for the one indoor unit; and after the total capacity requirement of the outdoor unit is calculated, returning an executable mode flag bit to the one indoor unit according to the mode flag bit and an operation status of the compressor, the executable mode flag bit being configured to instruct the one indoor unit to execute the breezeless mode, the gentle breeze mode, or the anti-direct blowing mode.

20. The method of claim 19, further comprising, after the total capacity requirement of the outdoor unit is calculated: recording a continuous operating duration of the compressor; determining that not all the plurality of indoor units operate in the air blowing mode in response to the continuous operating duration being less than or equal to a preset time or one or more of the plurality of indoor units operating in a regular cooling mode; and determining that all the plurality of indoor units operate in the air blowing mode in response to the continuous operating duration being greater than the preset time and each of the indoor units including the mode flag bit.

21. The method of claim 14, wherein adjusting the frequency of the compressor based on the initial frequency and according to the temperature characteristic values of the evaporator coils of all the plurality of indoor units and the reference evaporation temperature includes: determining an average temperature characteristic value according to the temperature characteristic values of the evaporator coils of all the plurality of indoor units; determining a first evaporation temperature and a second evaporation temperature greater than the first evaporation temperature according to the reference evaporation temperature and a correction temperature; increasing the frequency of the compressor to be greater than the initial frequency in response to the average temperature characteristic value being greater than the second evaporation temperature; reducing the frequency of the compressor to be less than the initial frequency in response to the average temperature characteristic value being less than the first evaporation temperature; and maintaining the frequency of the compressor unchanged in response to the average temperature characteristic value being between the first evaporation temperature and the second evaporation temperature.

22. The method of claim 21, wherein: a frequency range from a maximum frequency value to a minimum frequency value of the compressor is divided into a plurality of frequency levels according to a preset frequency interval; and the frequency of the compressor is increased or reduced by one or more frequency levels each time.

23. The method of claim 14, wherein: the evaporation temperature threshold is one of a first temperature threshold and a second temperature threshold greater than the first temperature threshold; and adjusting the frequency of the compressor based on the initial frequency and according to the temperature characteristic values of the evaporator coils of all the indoor units and the preset evaporation temperature threshold includes: determining an average temperature characteristic value according to the temperature characteristic values of the evaporator coils of all the plurality of indoor units; increasing the frequency of the compressor to be greater than the initial frequency in response to the average temperature characteristic value being greater than the second temperature threshold; reducing the frequency of the compressor to be less than the initial frequency in response to the average temperature characteristic value being less than the first temperature threshold; and maintaining the frequency of the compressor unchanged in response to the average temperature characteristic value being between the first temperature threshold and the second temperature threshold.

24. The method of claim 23, wherein: a frequency range from a maximum frequency value to a minimum frequency value of the compressor is divided into a plurality of frequency levels according to a preset frequency interval; and the frequency of the compressor is increased or reduced by one or more frequency levels each time.

25. A non-transitory computer-readable storage medium storing computer-executable instructions that, when executed by a processor, cause the processor to perform the method of claim 14.

26. A controller comprising: a memory storing a computer program; and a processor configured to execute the computer program to: determine an actual capacity requirement and a target evaporation temperature of each of a plurality of indoor units of the multi-split air conditioning system; calculate a total capacity requirement of an outdoor unit of the multi-split air conditioning system according to the actual capacity requirements of the plurality of indoor units; determine an initial frequency of a compressor according to the total capacity requirement; in response to all the plurality of indoor units operating in an air blowing mode: determine the target evaporation temperature corresponding to an indoor unit having a lowest dew point temperature as a reference evaporation temperature; and adjust a frequency of the compressor based on the initial frequency and according to temperature characteristic values of evaporator coils of all the plurality of indoor units and the reference evaporation temperature; and in response to not all the plurality of indoor units operating in the air blowing mode, adjust the frequency of the compressor based on the initial frequency and according to the temperature characteristic values of the evaporator coils of all the plurality of indoor units and a preset evaporation temperature threshold.

27. A multi-split air conditioning system comprising: an outdoor unit; a plurality of indoor units; and a controller including: a memory storing a computer program; and a processor configured to execute the computer program to: determine an actual capacity requirement and a target evaporation temperature of each of the plurality of indoor units; calculate a total capacity requirement of the outdoor unit according to the actual capacity requirements of the plurality of indoor units; determine an initial frequency of a compressor according to the total capacity requirement; in response to all the plurality of indoor units operating in an air blowing mode: determine the target evaporation temperature corresponding to an indoor unit having a lowest dew point temperature as a reference evaporation temperature; and adjust a frequency of the compressor based on the initial frequency and according to temperature characteristic values of evaporator coils of all the plurality of indoor units and the reference evaporation temperature; and in response to not all the plurality of indoor units operating in the air blowing mode, adjust the frequency of the compressor based on the initial frequency and according to the temperature characteristic values of the evaporator coils of all the plurality of indoor units and a preset evaporation temperature threshold.

28. The multi-split air conditioning system of claim 27, wherein for each indoor unit, the actual capacity requirement is determined according to a required refrigeration capacity value, a rated cooling capacity, a fan speed, and an operation mode of the indoor unit, the required refrigeration capacity value is determined according to an indoor temperature and a set temperature corresponding to the indoor unit, and the operation mode is the air blowing mode or a regular cooling mode.

29. The multi-split air conditioning system of claim 27, wherein for each indoor unit, the target evaporation temperature is determined according to a dew point temperature of the indoor unit, a heat transfer temperature difference correction parameter, and a mode correction parameter corresponding to the air blowing mode, and the dew point temperature is determined according to an indoor humidity and an indoor temperature that correspond to the indoor unit.

30. The multi-split air conditioning system of claim 27, wherein the processor is further configured to execute the computer program to, when determining the initial frequency: round the total capacity requirement as a frequency level of the compressor; and determine a frequency value corresponding to the frequency level as the initial frequency.

31. The multi-split air conditioning system of claim 30, wherein the processor is further configured to execute the computer program to, when determining the frequency value corresponding to the frequency level as the initial frequency includes: divide a frequency range from a maximum frequency value to a minimum frequency value of the compressor into a plurality of frequency levels according to a preset frequency interval; and calculate the initial frequency according to the result of the rounding, the preset frequency interval, and the minimum frequency value.

32. The multi-split air conditioning system of claim 27, wherein: the air blowing mode includes a breezeless mode, a gentle breeze mode, or an anti-direct blowing mode; and the processor is further configured to execute the computer program to, for one indoor unit of the plurality of indoor units: during acquisition of the actual capability requirement of the one indoor unit, receive a mode flag bit sent by the one indoor unit, the mode flag bit indicating to turn on the breezeless mode, the gentle breeze mode, or the anti-direct blowing mode for the one indoor unit; and after the total capacity requirement of the outdoor unit is calculated, return an executable mode flag bit to the one indoor unit according to the mode flag bit and an operation status of the compressor, the executable mode flag bit being configured to instruct the one indoor unit to execute the breezeless mode, the gentle breeze mode, or the anti-direct blowing mode.

33. The multi-split air conditioning system of claim 32, wherein the processor is further configured to execute the computer program to, after the total capacity requirement of the outdoor unit is calculated: record a continuous operating duration of the compressor; determine that not all the plurality of indoor units operate in the air blowing mode in response to the continuous operating duration being less than or equal to a preset time or one or more of the plurality of indoor units operating in a regular cooling mode; and determine that all the plurality of indoor units operate in the air blowing mode in response to the continuous operating duration being greater than the preset time and each of the indoor units including the mode flag bit.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0043] FIG. 1 is an architectural diagram of a multi-pipe multi-split air conditioning system according to an embodiment of the present disclosure;

[0044] FIG. 2 is an overall flowchart of a method for controlling according to an embodiment of the present disclosure;

[0045] FIG. 3 is a flowchart of calculating an initial frequency of a compressor according to an embodiment of the present disclosure;

[0046] FIG. 4 is a flowchart for dividing frequency values of the compressor into a plurality of frequency levels and determining the initial frequency according to an embodiment of the present disclosure;

[0047] FIG. 5 is a flowchart of interaction using a mode flag bit and an executable mode flag according to an embodiment of the present disclosure;

[0048] FIG. 6 is a flowchart of determining a combination of operation modes of indoor units based on a continuous operating duration according to an embodiment of the present disclosure;

[0049] FIG. 7 is a flowchart of controlling the compressor frequency when all indoor units operate in an air blowing mode according to an embodiment of the present disclosure;

[0050] FIG. 8 is a flowchart of controlling the compressor frequency when not all indoor units operate in an air blowing mode according to an embodiment of the present disclosure; and

[0051] FIG. 9 is a structural connection diagram of a controller according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0052] To make the objects, technical schemes, and advantages of the present disclosure clearer, the present disclosure is described in further detail in conjunction with accompanying drawings and embodiments. It should be understood that the embodiments described herein are merely used to illustrate the present disclosure but are not to limit the present disclosure. In addition, the features, operations, or characteristics described in the description may be combined in any suitable manner to form various embodiments. Moreover, the order of steps or actions in the description of the method may be changed or adjusted in a manner apparent to those having ordinary skills in the art. Therefore, the orders in the description and drawings are merely for the purpose of clearly describing a particular embodiment, and are not meant to be necessary orders unless otherwise specified that a particular order must be followed.

[0053] In the description of the present disclosure, the term at least one means one or more, the term plurality of (or multiple) means at least two, the term such as greater than, less than, exceed or variants thereof prior to a number or series of numbers is understood to not include the number adjacent to the term. The term at least prior to a number or series of numbers is understood to include the number adjacent to the term at least, and all subsequent numbers or integers that could logically be included, as clear from context. If used herein, the terms such as first, second, etc., are merely used for distinguishing technical features, and are not intended to indicate or imply relative importance, or implicitly point out the number of the indicated technical features, or implicitly point out the order of the indicated technical features.

[0054] The serial numbers assigned herein to components, such as first, second, etc., are merely used to distinguish the described objects and do not have any sequential or technical meaning. The terms such as connect, couple, and their variants in the present disclosure include direct and indirect connection (coupling) unless otherwise specified.

[0055] As users have higher requirements for quality of life, higher requirements are posed on the comfort of air-conditioning products. Single-split air conditioners such as wall-mounted air conditioners and cabinet air conditioners have been provided with breezeless air blowing functions with better comfort (including breezeless, gentle breeze, and anti-direct blowing modes, etc.). It is also necessary to improve user experience for multi-pipe multi-split air conditioners. However, multi-pipe multi-split air conditioning systems are different from single-split air conditioning systems. A multi-pipe multi-split air conditioning system includes an outdoor unit and a plurality of indoor units each connected to the outdoor unit by a separate piping. A change of the operation status of an indoor unit will affect the operation status of the outdoor unit, which in turn affects the operation statuses of all indoor units that are operating.

[0056] As compared with the control of breezeless air blowing modes of single-split air conditioning systems such as wall-mounted air conditioners and cabinet air conditioners, the control of the breezeless air blowing modes of multi-pipe multi-split air conditioning systems is more likely to have the risk of dewing and low outlet air temperature. Therefore, it is necessary to control the breezeless air blowing modes of the multi-split air conditioning system from the perspective of the entire air conditioning system.

[0057] The problems are determined by the characteristics of multi-pipe multi-split air conditioning systems.

[0058] First, the outdoor unit of the multi-split air conditioning system cooperates with a plurality of indoor units. When a small number of indoor units, e.g., one or two indoor units, are turned on, the minimum load of the outdoor unit is still too large for the load required by these indoor units. Especially when the indoor unit operates in the breezeless mode, the fan speed of the indoor unit is too small, the load of the indoor unit is further reduced, and the outlet air temperature of the indoor unit is too low.

[0059] Second, the operation of the outdoor unit will affect the operation statuses of all indoor units, so when the operation status of the outdoor unit changes, the indoor units need to perform self-adjustment to reduce this impact. For example, when one indoor machine is operating in the cooling mode and another indoor unit is operating in the breezeless mode, the frequency of the outdoor unit will be changed in order to ensure the cooling effect. If flow distribution is not performed for the indoor units, the outlet air temperature of the indoor unit in the breezeless mode will be significantly lower than that of the indoor unit in the cooling mode. When all indoor units are operating in the breezeless mode, the operating statuses of all the indoor units should be considered to ensure reliability first.

[0060] Third, different breezeless air blowing modes of indoor units (anti-direct blowing, gentle breeze, and breezeless modes) have different requirements on the cooling capacity output, and the requirements of the anti-direct blowing, gentle breeze, and breezeless modes on the cooling capacity output are in a descending order. In addition, indoor units with different deflector angles have different anti-dewing requirements, and therefore need to be controlled to have different outlet air temperatures.

[0061] At present, the control of multi-pipe multi-split air conditioning systems in the case of using the breezeless air blowing function fails to consider the coordination between the indoor units and the outdoor unit, cannot meet the cooling capacity output requirements of different breezeless air blowing modes, so it likely to cause excessively low outlet air temperature or dewing, affecting the user experience.

[0062] In view of the above, embodiments of the present disclosure provide a method for controlling a multi-split air conditioning system, a controller, an air conditioning system, and a medium. A total capacity requirement of an outdoor unit is determined according to an actual capacity requirement, a target evaporation temperature, and a current operation mode of each indoor unit, and an initial frequency and a frequency adjustment mode of a compressor are in turn determined to improve the cooperation between the outdoor unit and the indoor units, thereby improving the user experience.

[0063] The present disclosure will be further described below in conjunction with the accompanying drawings.

[0064] Referring to FIG. 1 and FIG. 2, an embodiment of the present disclosure provides a method for controlling a multi-split air conditioning system. At least a part of indoor units having a refrigeration requirement in a multi-split air-conditioning system has an air blowing mode turned on. The method includes the following steps.

[0065] In a step of S100, an actual capacity requirement and a target evaporation temperature of each of the indoor units having the refrigeration requirement are determined.

[0066] In a step of S200, a total capacity requirement of an outdoor unit is calculated according to the actual capacity requirements, and an initial compressor frequency is determined according to the total capacity requirement.

[0067] In a step of S300, when all the indoor units having the refrigeration requirement operate in the air blowing mode, the target evaporation temperature corresponding to the indoor unit having a lowest dew point temperature is determined as a reference evaporation temperature, and a compressor frequency is adjusted based on the initial frequency and according to temperature characteristic values of evaporator coils of all the indoor units and the reference evaporation temperature.

[0068] In a step of S400, when only a part of the indoor units having the refrigeration requirement operate in the air blowing mode, the compressor frequency is adjusted based on the initial frequency and according to the temperature characteristic values of the evaporator coils of all the indoor units and a preset evaporation temperature threshold.

[0069] First, it should be noted that the multi-split air-conditioning system mentioned in the present disclosure refers to a multi-pipe multi-split system. Each indoor unit is connected to the outdoor unit through its own piping (refrigerant pipeline). A refrigerant is converged in the outdoor unit and inputted into an air inlet of the compressor. Then, the refrigerant is outputted from an exhaust outlet of the compressor and distributed at the outdoor unit to the indoor units. For convenience of description, the term multi-split air conditioning system is used below to represent the multi-pipe multi-split air conditioning system. FIG. 1 is a schematic structural diagram showing the connection between components of the multi-split air conditioning system. Referring to FIG. 1, an air outlet of the compressor is connected to a condenser of the outdoor unit through a four-way valve. An outlet of the condenser is respectively connected to a plurality of indoor units (FIG. 1 takes four indoor units as an example: indoor unit A, indoor unit B, indoor unit C, and indoor unit D) through refrigerant pipelines. An independent refrigerant pipeline is arranged between an evaporator inlet of each indoor unit and the outlet of the condenser of the outdoor unit. Each independent refrigerant pipeline has a throttling element. An evaporator outlet of each indoor unit is also connected to an independent refrigerant pipe. After these refrigerant pipelines converge, the refrigerant enters an air-liquid separator through the four-way valve and finally returns to the air inlet of the compressor. In addition, the air blowing mode mentioned in the present disclosure is an operation mode in which the indoor unit reduces the amount of air blown directly to the user, and includes, but not limited to, breezeless, gentle breeze, and anti-direct blowing functions commonly seen in conventional air conditioners. Therefore, the air blowing mode is a general term for these functional modes, and also make the following scheme consider to distinguish the differences between cooling capacity output requirements of the breezeless, gentle breeze, and anti-direct blowing functions in the following description is also considered.

[0070] In the multi-split air conditioning system, a plurality of indoor units are used in combination with one outdoor unit. During operation of the plurality of indoor units, different indoor units may operate in different modes. For example, there is an indoor unit operating in the breezeless mode, an indoor unit operating in the anti-direct blowing mode, and an indoor unit operating in the regular cooling mode. To meet the cooling capacity requirements of the indoor units in various modes, the outdoor unit has to control the compressor to operate in an appropriate frequency range to obtain a better user experience. In an embodiment of the present disclosure, the actual capacity requirement of each indoor unit having the refrigeration requirement is determined, the total capacity requirement of the outdoor unit is determined according to the actual capacity requirements, and the initial compressor frequency is determined according to the total capacity requirement of the outdoor unit. When the compressor operates at the initial frequency, the compressor frequency is adjusted based on the initial frequency according to the current operation mode of each indoor unit, so as to enable cooperated operation between the outdoor unit and the indoor units. When all the indoor units having the refrigeration requirement operate in the air blowing mode, for example, the target evaporation temperature corresponding to the indoor unit having a lowest dew point temperature is determined as a reference evaporation temperature, and the compressor frequency is adjusted based on the initial frequency and in consideration of a relationship between the temperature characteristic values of the evaporator coils of all the indoor units and the reference evaporation temperature. When not all the indoor units having the refrigeration requirement operate in the air blowing mode, the compressor frequency is adjusted based on the initial frequency by using the preset evaporation temperature threshold as a reference and in consideration of a relationship between the temperature characteristic values of the evaporator coils of all the indoor units and the evaporation temperature threshold. Generally, after all the indoor units having the refrigeration requirement in the multi-split air conditioning system enter the air blowing mode, the outlet air temperature drops. It is necessary to adjust the compressor frequency to increase the evaporation temperature, so as to increase the degree of superheat of the evaporator of the indoor unit to increase the outlet air temperature of the indoor unit, thereby preventing the occurrence of indoor dewing while meeting the requirements of the air blowing mode. If there are still some indoor units operating in a regular cooling mode among the indoor units of the multi-split air conditioning system, priority should be given to ensuring the operation of the indoor units having a regular cooling requirement, and dewing in the room where the indoor unit in the air blowing mode is located should be avoided as much as possible. In short, the compressor is adjusted according to the operation modes of different indoor units, thereby realizing the cooperation between the outdoor unit and the indoor units. A specific method of controlling the compressor frequency will be described later.

[0071] The actual capacity requirement of the indoor unit is determined according to the following ways.

[0072] The actual capacity requirement of the indoor unit is determined according to a required refrigeration capacity value, a rated cooling capacity, a fan speed, and an operation mode of the indoor unit. The required refrigeration capacity value is determined according to an indoor temperature and a set temperature corresponding to the indoor unit, and the operation mode includes the air blowing mode and a regular cooling mode. In an embodiment, the actual capacity requirement may be:

[00001]$\mathrm{Cn}=A*\mathrm{HP}*\mathrm{K\_fan}*\mathrm{K\_nofan}$

where Cn represents an actual capacity requirement of an nth indoor unit in the multi-split air conditioning system, A represents the required refrigeration capacity value of the indoor unit, PH represents the rated cooling capacity of the indoor unit, K_fan represents the fan speed of the indoor unit, and K_nofan represents the operation mode of the indoor unit. The values of A, HP, K_fan, and K_nofan may be determined with reference to Tables 1 to 4 below.

TABLE-US-00001 TABLE 1 Table of values of required refrigeration capacity value of indoor unit Value of A Value of A Interval ( C.) (recommended value) (available range) T1 Ts 1 3 2.5 to 4.5 0 T1 Ts < 1 2 1.5 to 3 1 T1 Ts < 0 1 0.5 to 2 T1 Ts < 1 0 0
where T1 represents the indoor temperature detected by the indoor unit, and Ts represents the set temperature of the indoor unit.

TABLE-US-00002 TABLE 2 Table of values of rated cooling capacity Value of HP Model (rated cooling (recommended Value of HP capacity) value) (available range) 2000 0.8 0.5 to 1.1 2600 1.0 0.8 to 1.25 3200/3500 1.2 0.9 to 1.35 4800/5300 1.5 1.2 to 1.8 7000 2.5 1.8 to 2.8 10500 3.1 2.5 to 3.8

TABLE-US-00003 TABLE 3 Table of values of fan speed Value of K_fan Value of K_fan Fan speed (recommended value) (available range) 1% to 30% 0.2 0.1 to 0.3 30% to 60% 0.4 0.3 to 0.5 60% to 80% 0.6 0.5 to 0.8 80% to 90% 1.0 0.8 to 1.1 100% 1.2 1.0 to 1.3

TABLE-US-00004 TABLE 4 Table of values of operation mode Value of K_nofan Value of K_nofan (recommended (available Operation mode value) range) Breezeless 0.2 0.05 to 0.3 Gentle breeze 0.4 0.2 to 0.5 Anti-direct blowing 0.6 0.3 to 0.8 Cooling 1 No correction is needed in the cooling mode

[0073] It can be seen from foregoing Tables 1 to 4 that the required refrigeration capacity value, the rated cooling capacity, the fan speed, and the operation mode are all converted to corresponding numerical values to calculate the actual capacity requirement. That is, the value of A is determined according to a difference between the indoor temperature and the set temperature of the indoor unit, and is divided into four levels, respectively with values of 0, 1, 2, and 3. The value of PH is determined according to the rated cooling capacity of the indoor unit. For indoor units of the same manufacturer, different models represent different rated cooling capacities, respectively with values of 0.8, 1.0, 1.2, 1.5, 2.5, and 3.1. K_fan is divided into five intervals according to the percentage of the fan speed, respectively with values of 0.2, 0.4, 0.6, 1.0, and 1.2. K_nofan is determined according to different actual operation modes. Actual airflow speeds of the breezeless mode, the gentle breeze mode, the anti-direct blowing mode, and the regular cooling mode are in an ascending order, and respectively have values of 0.2, 0.4, 0.6, and 1.0. In addition, it can be seen from Tables 1 to 4 that in addition to the recommended values, an available range is also provided for each value. The actual values may be selected freely by those having ordinary skills in the art according to the available ranges, and are not limited to the recommended values.

[0074] The target evaporation temperature of the indoor unit is determined according to the following ways.

[0075] The target evaporation temperature of the indoor unit is determined according to a dew point temperature of the indoor unit, a heat transfer temperature difference correction parameter, and a mode correction parameter corresponding to the air blowing mode. The dew point temperature is determined according to an indoor humidity and an indoor temperature which both correspond to the indoor unit. In an embodiment, the target evaporation temperature may be:

[00002]$\mathrm{T2\_trg}=\mathrm{Td}-T+\mathrm{Ca}+\mathrm{Cb}$

where T2_trg represents the target evaporation temperature of the indoor unit, Td represents the dew point temperature, Ca represents a correction coefficient corresponding to the gentle breeze mode, and Cb represents a correction coefficient corresponding to the anti-direct blowing mode. The dew point temperature is determined by:

[00003]$\mathrm{Td}=-35.957-1.8726\left(\ln H1+\frac{c8}{T}+c9+c10*T+c11*T^2+c12*T^3+c13*\ln T\right)+1.1689{\left(\ln H1+\frac{c8}{T}+c9+c10*T+c11*T^2+c12*T^3+c13*\ln T\right)}^2$$c8=-5800.2206$$c9=1.3914993$$c10=-0.04860239$$c11=0.41764768*{10}^{-4}$$c12=-0.14452093*{10}^{-7}$$c13=6.5459673$

where H1 represents the indoor humidity detected by the indoor unit and has a value range of [20%, 90%], T=T1+273.15, and T1 has a value range of [16, 30] C. AT represents a correction coefficient, which may be regarded as a heat transfer temperature difference, has a recommended value of 4 C., and may have a value range of [2, 10] C. The final calculated Td has a value range of [6, 22] C. The values of Ca and Cb may be determined with reference to Tables 5 and 6 below.

TABLE-US-00005 TABLE 5 Table of values of correction parameter in gentle breeze mode Ca value Ca value Temperature range (recommended value) (available range) <70% 0 / 70% to 80% 1 5 to 1 80% to 100% 0.5 0.3 to 1.2

TABLE-US-00006 TABLE 6 Table of values of correction parameter in anti-direct blowing mode Cb value Cb value Temperature range (recommended value) (available range) <70% 0 / 70% to 80% 2 5 to 1 80% to 100% 1 0.5 to 2

[0076] It should be noted that the operation mode of the indoor unit may be determined by a mode flag bit. When a flag bit corresponding to the gentle breeze mode of the indoor unit is detected and the humidity is greater than 70%, the value in Table 5 above is applied. When the flag bit corresponding to the gentle breeze mode of the indoor unit is not detected or the humidity is less than 70%, the value of Ca is directly set to zero. When a flag bit corresponding to the anti-direct blowing mode of the indoor unit is detected and the humidity is greater than 70%, the value in Table 6 above is applied. When the flag bit corresponding to the anti-direct blowing mode of the indoor unit is not detected or the humidity is less than 70%, Cb is directly set to zero. It can be understood that for any indoor unit, only one mode flag bit can exist at a time, i.e., the value of at least one of Ca and Cb is set to zero.

[0077] The actual capacity requirement Cn of each indoor unit is obtained through the above calculation, and then the total capacity requirement of the outdoor unit is calculated according to the actual capacity requirements. The total capacity requirement may be obtained by:

[00004]$\mathrm{Qn}=\mathrm{K\_out}*.Math.\mathrm{Cn}$

where Qn represents the total capacity requirement of the outdoor unit, and K_out represents a preset outdoor unit coefficient value.

[0078] Referring to FIG. 3, determining an initial compressor frequency of the multi-split air-conditioning system according to the total capacity requirement in the step S200 includes the following steps.

[0079] In a step of S210, the total capacity requirement is rounded, and a result of the rounding is determined as a frequency level of the compressor.

[0080] In a step of S220, a frequency value corresponding to the frequency level is determined as the initial compressor frequency.

[0081] For example, the calculation result of the total capacity requirement Qn is 8.2. If rounding up is applied, the result of the rounding is 9, and the frequency level of the compressor is determined to be F9. If rounding down is applied, the result of the rounding is 8, and the frequency level of the compressor is determined to be F8. Then, the initial compressor frequency is determined according to the frequency level of the compressor. It can be understood that a correspondence between the compressor frequencies of the and the frequency levels is set in advance in the embodiment of the present disclosure, such that the corresponding initial frequency can be directly found through query according to the result of the rounding.

[0082] In some embodiments, referring to FIG. 4, the frequencies may be divided into the frequency levels by the following steps.

[0083] In a step of S221, a frequency range from a maximum frequency value to a minimum frequency value of the compressor is divided into a plurality of frequency levels according to a preset frequency interval.

[0084] In a step of S222, the initial compressor frequency is calculated according to the result of the rounding, the preset frequency interval, and the minimum frequency value.

[0085] The maximum frequency value and the minimum frequency value of the compressor are respectively defined as Fmax and Fmin. The frequency range between Fmax and Fmin is divided according to the preset frequency interval F, and a total sequence quantity N=(FmaxFmin)/F, where N is a positive integer, and the value of F may be 2 Hz to 5 Hz.

[0086] Assuming that the result of the rounding is represented by n, the frequency level is n, and the corresponding initial frequency is Fn=Fmin+(n1)*F. In practice, due to stress or other reasons, the actual initial compressor frequency may be adjusted near the value of Fn. It should be noted that the value of the total capacity requirement Qn is not directly correlated to the value of the total sequence quantity N, and therefore, to prevent the result of rounding Qn exceeds the total sequence quantity N, the value of K_out may be set to limit the value of Qn, which will not be described in detail herein.

[0087] As described above, the indoor unit has a mode flag bit in the air blowing mode, and the mode flag bit is sent to the outdoor unit, such that the outdoor unit determines whether to turn on the air blowing mode of the corresponding indoor unit. It is helpful in a scenario in which an indoor unit not having the air blowing mode and an indoor unit having the air blowing mode are used in combination. The air blowing mode includes a breezeless mode, a gentle breeze mode, and an anti-direct blowing mode. Referring to FIG. 5, the method further includes the following steps.

[0088] In a step of S201, during acquisition of the actual capability requirements, a mode flag bit sent by each of the indoor units having the refrigeration requirement is received. The mode flag bit indicates that one of the breezeless mode, the gentle breeze mode, or the anti-direct blowing mode of the indoor unit is to be turned on.

[0089] In a step of S202, after the total capacity requirement of the outdoor unit is calculated, an executable mode flag bit is returned to the indoor unit corresponding to the mode flag bit according to the mode flag bit and an operation status of the compressor. The executable mode flag bit is used to instruct the indoor unit to execute one of the breezeless mode, the gentle breeze mode, or the anti-direct blowing mode.

[0090] The indoor unit may not enter an air blowing mode immediately after receiving an air blowing mode instruction set by the user. For example, the indoor unit has just been started and the temperature in the room has not yet dropped. In this case, although the air blowing mode of the indoor unit has been turned on, the temperature in the room needs to be cooled down first, and then the airflow speed of the indoor unit is reduced to enter the air blowing mode, to adjust the temperature and humidity and take anti-dewing measures. Therefore, in practice, each indoor unit sends an actual capacity requirement carrying a mode flag bit to the outdoor unit, and the outdoor unit calculates a total capacity requirement according to the actual capacity requirements and determines the mode flag bit of each indoor unit. In this case, the indoor units have to comply with the adjustment made by the outdoor unit, and even if a room environment in which an indoor unit is located allows the indoor unit to operate in the breezeless mode, the gentle breeze mode, or the anti-direct blowing mode, the indoor unit does not immediately enter the corresponding operation mode. After obtaining the total capacity requirement, the outdoor unit determines an initial compressor frequency, acquires operation modes that the indoor units are about to enter respectively, and determines whether each indoor unit can execute the operation mode corresponding to the corresponding mode flag bit. The outdoor unit returns an executable mode flag bit to the corresponding indoor unit, to indicate that the indoor unit is allowed to enter the operation mode corresponding to the mode flag bit. When an indoor unit sends the flag bit corresponding to the anti-direct blowing mode to the outdoor unit, the outdoor unit, after acquiring the mode flag bits of all the indoor units having a cooling requirement, determines the initial compressor frequency and determines that the indoor unit can perform an anti-direct blowing function, and further returns an executable anti-direct blowing mode flag bit to the indoor unit. The indoor unit receives the executable anti-direct blowing mode flag bit, and executes the anti-direct blowing mode.

[0091] It should be noted that as mentioned above, the indoor units and the outdoor unit are not originally a complete set. Because indoor units of different models have different functions, some indoor units may have new functions, and some indoor units may only have the regular cooling function. Additionally, the outdoor unit may not have the function of adjusting the air blowing mode. In this case, the outdoor unit cannot return an executable mode flag bit to the indoor unit. Even if the indoor unit is equipped with the air blowing mode, it cannot perform an operation related to the air blowing mode. As such, comfort and reliability risks are avoided.

[0092] To determine a combination of operation modes of the indoor units, after the total capacity requirement of the outdoor units is calculated, referring to FIG. 6, the method of the embodiment of the present disclosure further includes the following steps.

[0093] In a step of S301, a continuous operating duration of the compressor is recorded.

[0094] In a step of S302, it is determined that only a part of the indoor units having the refrigeration requirement operate in the air blowing mode when the continuous operating duration is less than or equal to a preset time or at least a part of the indoor units having the refrigeration requirement operate in a regular cooling mode.

[0095] In a step of S303, it is determined that all the indoor units having the refrigeration requirement operate in the air blowing mode when the continuous operating duration is greater than the preset time and each of the indoor units having the refrigeration requirement has the mode flag bit.

[0096] At an early stage of start-up of an indoor unit, the compressor has just started to operate. Even if a user turns on an air blowing mode, the indoor unit has to lower the temperature in the room before entering the corresponding air blowing mode. Therefore, when the outdoor unit determines whether to allow the indoor unit to enter the air blowing mode, the continuous operating duration of the compressor and the actual capacity requirement of the indoor unit have to be considered. For example, when the continuous operating duration of the compressor is less than or equal to the preset time, the outdoor unit does not allow the corresponding one or more indoor units to enter the air blowing mode, and the compressor frequency is controlled according to a control procedure corresponding to a case where not all the indoor units operate in the air blowing mode. Alternatively, when the outdoor unit finds according to the acquired mode flag bits of the indoor units that one or more indoor units operate in the regular cooling mode flag bit, the compressor frequency is controlled according to a control procedure corresponding to the case where not all the indoor units operate in the air blowing mode. When the continuous operating duration of the compressor is greater than the preset time and the outdoor unit finds according to the acquired mode flag bits of the indoor units that all the indoor units operate in the air blowing mode flag bit, the compressor frequency is controlled according to a control procedure corresponding to a case where all the indoor units operate in the air blowing mode. The control procedure corresponding to the case where not all the indoor units operate in the air blowing mode is different from the control procedure corresponding to the case where all the indoor units operate in the air blowing mode. The two control procedures use different temperature thresholds as a reference to adjust the temperature characteristic values of the evaporator coils, and therefore adjustment methods are different from each other. The two control procedures are respectively described below.

[0097] In the control procedure for the case where all the indoor units operate in the air blowing mode, such as the step S300, after the actual capacity requirements of the indoor unit are acquired, the indoor unit having the lowest dew point temperature among the indoor units is selected, and the target evaporation temperature of the selected indoor unit is determined as the reference evaporation temperature. Then, the compressor frequency is controlled according to the temperature characteristic values of the evaporator coils of all the indoor units and the reference evaporation temperature. Referring to FIG. 7, it may include the following steps.

[0098] In a step of S310, an average temperature characteristic value is determined according to the temperature characteristic values of the evaporator coils of all the indoor units.

[0099] In a step of S320, a first evaporation temperature and a second evaporation temperature are determined according to the reference evaporation temperature and a correction temperature. The first evaporation temperature is less than the second evaporation temperature.

[0100] In a step of S330, the compressor frequency is increased to be greater than the initial frequency when the average temperature characteristic value is greater than the second evaporation temperature.

[0101] In a step of S340, the compressor frequency is reduced to be less than the initial frequency when the average temperature characteristic value is less than the first evaporation temperature.

[0102] In a step of S350, the compressor frequency is maintained unchanged when the average temperature characteristic value is between the first evaporation temperature and the second evaporation temperature.

[0103] The temperature characteristic values of the evaporator coils of all the indoor units are calculated (where the temperature characteristic values are represented by T2) to obtain an average temperature characteristic value, which is represented by T2_avg. The target evaporation temperature of the indoor unit having the lowest dew point temperature is determined as the reference evaporation temperature, which is represented by T2x. The correction temperature is represented by m. Therefore, the first evaporation temperature may be T2x-m, and the second evaporation temperature may be T2x+m. The average temperature characteristic value T2_avg is compared with the first evaporation temperature T2x-m and the second evaporation temperature T2x+m.

[0104] When the average temperature characteristic value is greater than the second evaporation temperature, i.e., T2_avg>T2x+m, the compressor frequency is increased to be greater than the initial compressor frequency. When the average temperature characteristic value is less than the first evaporation temperature, i.e., T2_avg<T2x-m, the compressor frequency is decreased to be less than the initial compressor frequency. When the average temperature characteristic value is between the first evaporation temperature and the second evaporation temperature, i.e., T2x+m>T2_avg>T2x-m, the compressor frequency is maintained unchanged.

[0105] The correction temperature may have a recommended value of 1 C., and a recommended value range of 0.5 C. to 1.5 C. The average temperature characteristic value may be obtained by directly calculating an average value of the temperature characteristic values of all the indoor units, or may be obtained by other statistical calculation methods, such as weighted averaging, which is not limited herein.

[0106] In the control procedure for the case where not all the indoor units operate in the air blowing mode, such as the step S300, after the actual capacity requirements of the indoor units are acquired, the temperature characteristic values of the evaporator coils of the indoor units are compared with the first temperature threshold and the second temperature threshold which are preset, and the compressor frequency is adjusted according to a result of the comparison. Referring to FIG. 7, it may include the following steps.

[0107] In a step of S410, an average temperature characteristic value is determined according to the temperature characteristic values of the evaporator coils of all the indoor units.

[0108] In a step of S420, the compressor frequency is increased to be greater than the initial frequency when the average temperature characteristic value is greater than the second temperature threshold.

[0109] In a step of S430, the compressor frequency is reduced to be less than the initial frequency when the average temperature characteristic value is less than the first temperature threshold.

[0110] In a step of S440, the compressor frequency is maintained unchanged when the average temperature characteristic value is between the first temperature threshold and the second temperature threshold.

[0111] Similarly, the temperature characteristic values of the evaporator coils of all the indoor units are calculated (where the temperature characteristic value is represented by T2) to obtain an average temperature characteristic value, which is represented by T2_avg. The first temperature threshold is represented by a. The second temperature threshold is represented by b. The second temperature threshold b is greater than the first temperature threshold a.

[0112] When the average temperature characteristic value is greater than the second temperature threshold, i.e., T2_avg>b, the compressor frequency is increased to be greater than the initial compressor frequency. When the average temperature characteristic value is less than the first temperature threshold, i.e., T2_avg<a, the compressor frequency is decreased to be less than the initial compressor frequency. When the average temperature characteristic value is between the first temperature threshold and the second temperature threshold, i.e., b>T2_avg>a, the compressor frequency is maintained unchanged.

[0113] The first temperature threshold may have a recommended value of 7 C., and a recommended value range of 6 C. to 8 C. The second temperature threshold may have a recommended value of 10 C., and a recommended value range of 8 C. to 11 C. The average temperature characteristic value may be obtained by directly calculating an average value of the temperature characteristic values of all the indoor units, or may be obtained by other statistical calculation methods, such as weighted averaging, which is not limited herein.

[0114] It can be understood that each time the compressor frequency is adjusted, the actual capacity requirement and the target evaporation temperature of each indoor unit are re-acquired. If the total capacity requirement calculated according to the actual capacity requirements changes, the initial compressor frequency is re-determined, and the compressor frequency is controlled based on the new initial frequency. In this case, the average temperature characteristic value T2_avg generally also changes, so the compressor frequency is increased, reduced, or maintained unchanged according to the changed T2_avg. When the re-determined initial compressor frequency is identical to the previous initial frequency, i.e., the total capacity requirement has not changed, but the average temperature characteristic value T2_avg has changed, the compressor frequency has to be further increased, reduced, or maintained unchanged based on the frequency obtained through the previous adjustment. For a case where the compressor frequency is continuously increased, a maximum frequency threshold may be set. When the compressor frequency has been increased to the maximum frequency threshold, the compressor frequency will not be further increased even if T2_avg>T2x+m or T2_avg>b. Similarly, for a case where the compressor frequency is continuously reduced, a minimum frequency threshold may be set. When the compressor frequency has been reduced to the minimum frequency threshold, the compressor frequency will not be further reduced even if T2_avg<T2x-m or T2_avg<a.

[0115] For the adjustment of the compressor frequency, the compressor frequency may be increased or reduced in different manners. In some embodiments, the compressor frequency is controlled based on frequency levels, i.e., the compressor frequency is increased or reduced by one or more frequency levels in each adjustment. For example, the maximum frequency value and the minimum frequency value of the compressor are respectively defined as Fmax and Fmin. The frequency range between Fmax and Fmin is divided according to the preset frequency interval F. That is, a frequency span of each frequency level is F, and a total sequence quantity N=(FmaxFmin)/F, where Nis a positive integer, and the value of F may be 2 Hz to 5 Hz. In other words, the compressor frequency is adjusted based on frequency levels, and the frequency is increased or reduced by one or more frequency levels in each adjustment. Assuming that the frequency is increased or reduced by one frequency level in each adjustment, when T2_avg>T2x+m or T2_avg>b, the compressor frequency is increased by one frequency level based on the initial frequency Fn (nth frequency level), i.e., increased to F(n+1). If a result of calculation based on data acquired for the second next time indicates that the compressor frequency has to be further increased, the frequency is increased by one more frequency level to F(n+2). A maximum number of frequency levels by which the frequency can be increased may be set to x, i.e., the frequency will not be further increased once it has reached F(n+x). Similarly, when T2_avg<T2x-m or T2_avg<a, the compressor frequency is reduced by one frequency level based on the initial frequency Fn (nth frequency level), i.e., reduced to F(n1). If a result of calculation based on data acquired next time indicates that the compressor frequency has to be further reduced, the frequency is reduced by one more frequency level to F(n2). The frequency will not be further reduced once it has reached F1.

[0116] By the above method, when at least a part of a plurality of indoor units in the multi-split air conditioning system has an air blowing mode turned on, actual capacity requirements and target evaporation temperatures of all the indoor units having a refrigeration requirement are calculated, so as to determine a total capacity requirement corresponding to the outdoor unit and an initial compressor frequency corresponding to the total capacity requirement. During operation of the indoor units, the compressor frequency is adjusted in different manners based on the initial compressor frequency and depending on whether all the indoor units are operating in the air blowing mode, such that the outdoor unit can meet the refrigeration requirements of the indoor units corresponding to different combinations of operation modes, thereby improving the user experience of the multi-split air conditioning system. In addition, the adjustment of the compressor frequency in the above manner is based on the temperature characteristic value of the evaporator coil of each indoor unit, and the reference evaporation temperature or the evaporation temperature threshold is set depending on whether all the indoor units are operating in the air blowing mode, such that the outdoor unit can meet different mode requirements of the indoor units and reduce the probability of dewing in the air blowing mode.

[0117] In addition, an embodiment of the present disclosure provides a controller, including a memory, a processor, and a computer program stored in the memory and executable by the processor, where the computer program, when executed by the processor, causes the processor to implement the method described above.

[0118] Referring to FIG. 9, for example, a control processor 1001 and a memory 1002 in a controller 1000 may be connected via a bus. The memory 1002, as a non-transitory computer-readable storage medium, may be configured for storing a non-transitory software program and a non-transitory computer-executable program. In addition, the memory 1002 may include a high-speed random access memory, and may also include a non-transitory memory, e.g., at least one magnetic disk storage device, flash memory device, or other non-transitory solid-state storage device. In some implementations, the memory 1002 optionally includes a memory located remotely from the control processor 1001, and the remote memory may be connected to the controller 1000 via a network. Examples of the network include, but not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0119] Those having ordinary skills in the art may understand that the apparatus structure shown in FIG. 9 does not constitute a limitation to the controller 1000, and the controller 1000 may include more or fewer components than those shown in the figure, or some components may be combined, or a different component arrangement may be used.

[0120] In addition, an embodiment of the present disclosure provides an air conditioner including the controller 1000. The controller executes the method described above to ensure that the air conditioner can operate for the set operating time, thereby making full use of the remaining quantity of electricity of the battery, increasing the cooling capacity of the air conditioner in a recreational vehicle, and meeting the user's requirement on the operating time of the air conditioner.

[0121] In addition, an embodiment of the present disclosure provides a computer-readable storage medium, storing a computer-executable instruction configured to implement the method described above. The computer-executable instruction, when executed by one or more processors, for example, by a processor 1001 in FIG. 9, may cause the one or more processors to implement the method in the above method embodiments, for example, implement the steps S100 to S400 in FIG. 2, the steps S210 to S220 in FIG. 3, the steps S221 to S222 in FIG. 4, the steps S201 to S202 in FIG. 5, the steps S301 to S303 in FIG. 6, the steps S310 to S350 in FIG. 7, or the steps S410 to S420 in FIG. 8.

[0122] The apparatus embodiments described above are merely examples. The units described as separate components may or may not be physically separated, i.e., they may be located in one place or may be distributed over a plurality of network nodes. Some or all of the modules may be selected according to actual needs to achieve the objects of the scheme of this embodiment.

[0123] Those having ordinary skills in the art can understand that all or some of the steps in the methods disclosed above and the functional modules/units in the system and the apparatus can be implemented as software, firmware, hardware, and appropriate combinations thereof. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer-readable storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is known to those having ordinary skills in the art, the term computer-readable storage medium includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information (such as computer-readable instructions, data structures, program modules, or other data). The computer-readable storage medium includes, but not limited to, Random Access Memory (RAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), flash memory or other memory technology, Compact Disc Read-Only Memory (CD-ROM), Digital Versatile Disc (DVD) or other optical storage, cassette, magnetic tape, magnetic disk storage or other magnetic storage device, or any other medium which can be used to store the desired information and can be accessed by a computer. In addition, as well known to those having ordinary skills in the art, the communication medium typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier or other transport mechanism, and can include any information delivery medium.

[0124] Although some implementations of the present disclosure have been described above, the present disclosure is not limited to the implementations described above. Those having ordinary skills in the art can make various equivalent modifications or replacements without departing from the scope of the present disclosure. Such equivalent modifications or replacements fall within the scope defined by the claims of the present disclosure.