Control method for air conditioning system

Abstract

Disclosed in the present application is a control method for an air conditioning system. The method comprises: on the basis of historical learning data of an indoor unit and a load feature learning model, learning a refrigeration load parameter of a room corresponding to the indoor unit, wherein the refrigeration load parameter is obtained by means of self-learning; on the basis of a desired indoor temperature at the current moment, the refrigeration load parameter, an indoor temperature, an outdoor temperature and a control period, determining a required load at the current moment; and on the basis of the required load, controlling operating parameters of an air conditioning system.

Description

Control method of air conditioning system

[0001] This application claims priority to Chinese Patent Application No. 202411074126.3, filed on August 6, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of air conditioning, in particular to a control method of an air conditioning system. BACKGROUND

[0003] The control object of the current air conditioning system is usually the difference between the set temperature and the return air temperature, which is used as a key reference for the compressor frequency, evaporation temperature, superheat, etc. in the control system. However, since the temperature difference only reflects the target room temperature state, the temperature difference is only an important parameter in the air heat load item of the building load, and in the building load, heat leakage load, solar radiation load, and internal disturbance load are also important factors. Therefore, using the temperature difference as the control target alone can easily cause problems such as small temperature difference large load under-regulation, large temperature difference small load over-regulation, and medium load room temperature fluctuation, which also causes problems such as frequent start and stop of the unit, low energy efficiency, and poor user experience.

[0004] The above information disclosed in the background section of this specification is only for the purpose of increasing the understanding of the background of the present application, and therefore, it can include matters known by those skilled in the art. SUMMARY

[0005] The present application provides a control method of an air conditioning system, comprising:

[0006] determining a cooling load parameter of a corresponding room of an indoor unit based on historical learning data and a load feature learning model; the historical learning data includes indoor temperature, set temperature, outdoor temperature, and capacity of the indoor unit corresponding to a plurality of historical time points;

[0007] obtaining an indoor temperature at a current time and an outdoor temperature at the current time;

[0008] determining an expected indoor temperature at the current time;

[0009] determining a required load at the current time according to the cooling load parameter, the indoor temperature at the current time, the expected indoor temperature at the current time, the outdoor temperature at the current time, and a control period;

[0010] determining an operating parameter of the air conditioning system according to the required load at the current time.

[0011] According to the control method of the air conditioning system, the air conditioner learns the cooling load parameter of the room corresponding to the indoor unit according to historical learning data and a load feature learning model of the indoor unit, determines the demand load at the current moment according to the expected indoor temperature at the current moment, the cooling load parameter, the indoor temperature, the outdoor temperature and the control period, and controls the operation parameter of the air conditioning system according to the demand load. The cooling load parameter obtained through self-learning can more truly reflect the current load state of the room, and the determined demand load at the current moment can be adapted to the real-time load of the room corresponding to the indoor unit. Therefore, the operation parameter of the air conditioning system is controlled through the real-time demand load of the room, so that the operation state of the air conditioning system can be matched with the real-time demand load of the room, load following is realized, and control is performed to avoid under-regulation, over-regulation and room temperature fluctuation. In the case of small and medium load, the room temperature fluctuation can be reduced and the power consumption caused by frequent start-stop can be avoided, the system operation reliability is improved, energy saving and efficiency improvement are realized, and in the case of large load, the capacity of the indoor unit can be improved, the room temperature change speed is accelerated, and user comfort is improved.

[0012] In some embodiments, the load feature learning model is represented by the following formula: Q e =a×(T i -T s )+b×(T a -T i )×t1+c×t1

[0013] wherein Q e is the capacity of the indoor unit; a, b, and c are cooling load parameters; T i is the indoor temperature; T s is the set temperature; T a is the outdoor temperature; and t1 is the learning step.

[0014] The determination of the demand load at the current moment according to the cooling load parameter, the indoor temperature at the current moment, the expected indoor temperature at the current moment, the outdoor temperature at the current moment and the control period includes determining the demand load at the current moment based on the following formula: Q r(n) =a×(T i(n) -T exp(n) )+b×(T a(n) -T i(n) )×t2+c×t2

[0015] wherein Q r(n) is the demand load at the current moment; T i(n) is the indoor temperature at the current moment; T exp(n) is the expected indoor temperature; T a(n) is the outdoor temperature at the current moment; T i(n) is the indoor temperature; and t2 is the control period.

[0016] The demand load is determined according to the refrigeration load parameter, the difference between the indoor temperature and the expected indoor temperature, and the difference between the outdoor temperature and the indoor temperature, so that the accuracy of the determination of the demand load at the current time can be improved.

[0017] In some embodiments, the determination of the expected indoor temperature at the current time comprises:

[0018] The temperature characteristic constant, the initial time indoor temperature, the previous time indoor temperature, and the set temperature are obtained.

[0019] The expected indoor temperature at the current time is determined according to the initial time indoor temperature, the difference between the previous time indoor temperature and the set temperature, the difference between the initial time indoor temperature and the set temperature, the time from the initial time to the current time, and the temperature characteristic constant.

[0020] The expected indoor temperature determined in the above manner can quickly and accurately approach the set temperature, and the room temperature is quickly reduced according to the difference between the current time and the set temperature and the expected total cooling time in the early cooling stage, and the room temperature is accurately adjusted to the set temperature value in the late cooling stage.

[0021] In some embodiments, the operating parameter comprises a compressor frequency at the current time, and the determination of the compressor frequency at the current time according to the demand load at the current time comprises:

[0022] The actual indoor unit evaporation temperature at the current time is obtained.

[0023] The target evaporation temperature of the indoor unit at the current time is determined according to the demand load at the current time and the indoor temperature at the current time.

[0024] The compressor frequency at the previous time, the actual indoor unit evaporation temperature at the previous time, and the target evaporation temperature at the previous time are obtained.

[0025] The compressor frequency at the current time is determined according to the difference between the actual indoor unit evaporation temperature at the previous time and the target evaporation temperature at the previous time, the difference between the actual indoor unit evaporation temperature at the current time and the target evaporation temperature at the current time, and the compressor frequency at the previous time.

[0026] The air conditioning system determines a demand load at a current time, determines a target evaporating temperature at the current time according to the demand load at the current time, and determines a compressor frequency at the current time according to a difference between the actual evaporating temperature at the current time and the target evaporating temperature at the current time, a difference between the actual evaporating temperature at the previous time and the target evaporating temperature at the previous time, and the compressor frequency at the previous time. Thus, the air conditioning system determines the compressor frequency at the current time according to the demand load variation and the compressor frequency at the previous time, so as to realize load following control, match the operation capacity of the air conditioning system with the demand load, and realize smooth adjustment of the compressor frequency.

[0027] In some embodiments, the determining the compressor frequency at the current time according to the difference between the actual evaporating temperature of the indoor unit at the previous time and the target evaporating temperature at the previous time, the difference between the actual evaporating temperature of the indoor unit at the current time and the target evaporating temperature at the current time, and the compressor frequency at the previous time comprises:

[0028] obtaining a compressor characteristic parameter S, a compressor iterative correction coefficient m1 and a compressor iterative correction coefficient m2;

[0029] calculating the compressor frequency at the current time based on the following formula:

[0030] wherein H (n) is the compressor frequency at the current time;

[0031] H (n-1) is the compressor frequency at the previous time;

[0032] ΔT ep(n) is the difference between the actual evaporating temperature of the indoor unit at the current time and the target evaporating temperature at the current time;

[0033] ΔT ep(n-1) is the difference between the actual evaporating temperature of the indoor unit at the previous time and the target evaporating temperature at the previous time.

[0034] The compressor frequency is corrected by the compressor characteristic parameter S, the compressor iterative correction coefficient m and the compressor iterative correction coefficient n, so as to improve the accuracy of the determination of the compressor frequency.

[0035] In some embodiments, the determining the target evaporating temperature of the indoor unit at the current time according to the demand load at the current time and the indoor temperature at the current time comprises: obtaining a model characteristic parameter of the indoor unit, and determining the target evaporating temperature of the indoor unit at the current time according to the indoor temperature at the current time, the demand load at the current time, the model characteristic parameter of the indoor unit and the control period.

[0036] The target evaporating temperature at the current time is determined according to the demand load at the current time, so as to further control the compressor frequency.

[0037] In some embodiments, when the air conditioning system includes multiple indoor units, the minimum of the target evaporating temperature of the multiple indoor units at the current time is determined as the target evaporating temperature at the current time; and the average of the actual evaporating temperature of the multiple indoor units at the current time is determined as the actual evaporating temperature.

[0038] The minimum of the target evaporating temperature of all the indoor units is used as the target evaporating temperature, so that the determined compressor frequency can meet the demand load; and the average of the actual evaporating temperature of the multiple indoor units at the current time is used as the actual evaporating temperature, which can more accurately reflect the actual evaporating temperature of the system.

[0039] In some embodiments, the operating parameter includes a compressor frequency at an initial time, and the compressor frequency at the initial time is determined according to a demand load at the initial time, which includes:

[0040] obtaining a compressor characteristic parameter;

[0041] determining a demand load at an initial time;

[0042] determining a compressor frequency at the initial time according to the compressor characteristic parameter, the demand load at the initial time, and a control period.

[0043] The compressor frequency at the initial time is determined according to the demand load at the initial time, so that the compressor frequency at the initial time meets the demand load requirement at the initial time, and rapid cooling at the initial stage of refrigeration is realized.

[0044] In some embodiments, the operating parameter includes an indoor unit air damper, and the indoor unit air damper at the current time is determined according to the demand load at the current time, which includes:

[0045] obtaining a capacity characteristic coefficient of the indoor unit and the demand load at the current time, determining a compressor frequency correction coefficient according to the demand load at the current time, the capacity characteristic coefficient of the indoor unit, and the control period, and determining the indoor unit air damper according to the compressor frequency correction coefficient, wherein the indoor unit air damper is positively correlated with the compressor frequency correction coefficient.

[0046] The indoor unit air damper is adjusted according to the demand load at the current time, so as to further ensure that the capacity of the indoor unit meets the demand load.

[0047] In some embodiments, the air conditioning system includes an indoor expansion valve, and a control method of the indoor expansion valve includes:

[0048] determining a real-time superheat value of the indoor unit, when the real-time superheat value is below a set value, the indoor expansion valve opening degree remains unchanged, and when the real-time superheat value is above the set value, the indoor expansion valve opening degree is increased.

[0049] The indoor expansion valve opening degree is adjusted to ensure that the real-time superheat is below the set value, so as to ensure the normal operation of the compressor and the evaporation capacity of the indoor unit.

[0050] In some embodiments, the initial opening degree of the indoor expansion valve is determined according to the maximum opening degree of the indoor expansion valve, the ratio of the capacity value of the currently started indoor unit to the sum of the capacities of all started indoor units.

[0051] The initial opening degree of the indoor expansion valve determined in the above manner makes the refrigerant distribution more reasonable.

[0052] In some embodiments, the method for determining the amount of increase of the indoor expansion valve opening degree comprises:

[0053] An iteration correction coefficient of the superheat is obtained.

[0054] A difference between the superheat at the current time and the superheat at the last time is calculated as a first difference.

[0055] A difference between the superheat at the last time and the superheat at the time before the last time is calculated as a second difference.

[0056] The amount of increase of the indoor expansion valve opening degree is determined according to the first difference, the difference between the first difference and the second difference, and the iteration correction coefficient of the superheat.

[0057] The determination manner of the amount of increase of the indoor expansion valve opening degree can ensure the smooth adjustment of the indoor expansion valve opening degree.

[0058] Other features and advantages of the present application will become more apparent after reading the specific embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor.

[0060] FIG. 1 is a flowchart of a control method of an air conditioning system according to an embodiment.

[0061] FIG. 2 is a refrigerant circulation schematic diagram of the air conditioning system in a refrigeration mode according to an embodiment.

[0062] FIG. 3 is a flowchart of determining a refrigeration load parameter of the air conditioning system in a refrigeration mode according to an embodiment.

[0063] FIG. 4 is a flowchart of obtaining indoor unit historical operation data available for model learning of the air conditioning system in a refrigeration mode according to an embodiment.

[0064] Fig. 5 is a flow chart for determining a real-time demand load when the air conditioning system is in a cooling mode according to an embodiment.

[0065] Fig. 6 is a flow chart for determining a compressor frequency at an initial time when the air conditioning system is in a cooling mode according to an embodiment.

[0066] Fig. 7 is a flow chart for real-time control of the compressor frequency when the air conditioning system is in a cooling mode according to an embodiment.

[0067] Fig. 8 is a flow chart for determining an initial air damper at an initial time when the air conditioning system is in a cooling mode according to an embodiment.

[0068] Fig. 9 is a flow chart for control of the air damper when the air conditioning system is in a cooling mode according to an embodiment.

[0069] Fig. 10 is a flow chart for control of the indoor expansion valve when the air conditioning system is in a cooling mode according to an embodiment. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0071] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0072] The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0073] In the description of the application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0074] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature "under", "below" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0075] The following disclosure provides many different embodiments or examples for implementing different structures of the application. In order to simplify the disclosure of the application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0076] The air conditioning system given in the present application performs the refrigeration cycle of the air conditioner by using the compressor, the condenser, the throttling device and the evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion and evaporation, and performs refrigeration or heating for indoor space.

[0077] The low-temperature and low-pressure refrigerant enters the compressor, which compresses the refrigerant gas into a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process. The throttling device expands the high-temperature and high-pressure liquid-phase refrigerant condensed in the condenser into low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the throttling device and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by exchanging heat with the material to be cooled using the latent heat of evaporation of the refrigerant. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space.

[0078] The outdoor unit of the air conditioning system includes a compressor, an outdoor heat exchanger, and a throttling device.

[0079] The indoor unit of the air conditioning system includes an indoor heat exchanger, the air conditioning system includes at least one indoor unit, and each indoor unit is provided with an indoor expansion valve, and the capacity of the indoor unit is adjusted by adjusting the opening degree of the indoor expansion valve.

[0080] In some embodiments, the air conditioning system includes an outdoor unit and one indoor unit, the outdoor unit includes a compressor and an outdoor heat exchanger, and the indoor unit includes an indoor heat exchanger and an indoor expansion valve.

[0081] In some embodiments, the air conditioning system includes an outdoor unit and multiple indoor units, which is also called a multi-split system. The outdoor unit includes a compressor and an outdoor heat exchanger, and each indoor unit includes an indoor heat exchanger and an indoor expansion valve. The indoor heat exchanger and the outdoor heat exchanger serve as a condenser or an evaporator. When the indoor heat exchanger serves as a condenser, the air conditioner serves as a heater in a heating state, and when the indoor heat exchanger serves as an evaporator, the air conditioner serves as a cooler in a cooling state.

[0082] The present application provides a control method of an air conditioning system, comprising:

[0083] Based on historical learning data and load feature learning model, determine the cooling load parameters of the indoor unit corresponding to the room;

[0084] Obtain the indoor temperature at the current time and the outdoor temperature at the current time;

[0085] Determine the expected indoor temperature at the current time, and determine the demand load at the current time according to the cooling load parameters, the indoor temperature at the current time, the expected temperature at the current time, the outdoor temperature at the current time, and the control period;

[0086] Determine the operating parameters of the air conditioning system according to the demand load at the current time.

[0087] In some embodiments, the historical learning data includes indoor temperature, set temperature, outdoor temperature and capacity of the indoor unit corresponding to a plurality of historical time points.

[0088] The refrigeration load parameter of the air conditioning system is obtained through self-learning. The refrigeration load parameter obtained through self-learning can more accurately and truly reflect the current load state of the room. The further determined demand load at the current time point can be adapted to the real-time load of the room corresponding to the indoor unit. Therefore, the operation parameters of the air conditioning system are controlled by the real-time demand load of the room, so that the operation state of the air conditioning system can be matched with the real-time demand load of the room, avoiding the problems of under-regulation, over-regulation and room temperature fluctuation. At medium and small load, it can reduce the room temperature fluctuation and avoid the increase of power consumption caused by frequent start and stop, improve the system operation reliability, realize energy saving and efficiency improvement, and at large load, it can improve the capacity of the indoor unit, speed up the room temperature change speed and improve the user comfort.

[0089] In the embodiment of FIG. 1, the control method of the air conditioning system includes:

[0090] S1, start.

[0091] S2, determining the refrigeration load parameter of the room corresponding to the indoor unit based on the historical learning data and the load feature learning model.

[0092] S3, obtaining the indoor temperature and the outdoor temperature at the current time point.

[0093] S4, determining the expected indoor temperature at the current time point, and determining the demand load at the current time point according to the refrigeration load parameter, the indoor temperature at the current time point, the expected indoor temperature at the current time point, the outdoor temperature at the current time point and the control period.

[0094] S5, determining the operation parameters of the air conditioning system according to the demand load at the current time point. The following takes the air conditioning system as a multi-split system as an example for description. FIG. 2 is a refrigeration mode refrigerant circulation schematic diagram of the multi-split system. In the example of FIG. 2, the air conditioning system includes an outdoor unit and a first indoor unit, a second indoor unit and a third indoor unit. The outdoor unit is connected with the first indoor unit, the second indoor unit and the third indoor unit through a split pipe, forming the air conditioning system.

[0095] The outdoor unit is provided with a compressor 1, an outdoor heat exchanger 5, an outdoor expansion valve 6 and a four-way valve 4. The operation capacity of the outdoor unit can be adjusted by adjusting the operation frequency of the compressor 1.

[0096] The outdoor unit is further provided with an outdoor temperature acquisition module, which is used to acquire the outdoor temperature T a .

[0097] In some embodiments, the outdoor temperature acquisition module acquires the outdoor environment temperature through a hardware mode, for example, the outdoor environment temperature acquisition module is a temperature sensor arranged in the outdoor unit.

[0098] In some embodiments, the outdoor temperature acquisition module is configured to acquire the outdoor temperature by software, for example, the outdoor environment temperature acquisition module acquires the outdoor temperature through a network.

[0099] The first indoor unit is provided with a first indoor heat exchanger 18-1, a first indoor expansion valve 19-1 and a first indoor fan (not shown in the figure), and the operating capacity of the first indoor unit can be adjusted by adjusting the opening degree of the first indoor expansion valve 19-1 and / or the rotating speed of the first indoor fan.

[0100] The first indoor unit includes a first indoor environment temperature detection module d1, a first indoor unit liquid pipe temperature detection module c1 and a first indoor unit gas pipe temperature detection module b1.

[0101] The second indoor unit is provided with a second indoor heat exchanger 18-2, a second indoor expansion valve 19-2 and a second indoor fan, and the operating capacity of the second indoor unit can be adjusted by adjusting the opening degree of the second indoor expansion valve 19-2 and / or the rotating speed of the second indoor fan.

[0102] The second indoor unit includes a second indoor environment temperature detection module d2, a second indoor unit liquid pipe temperature detection module c2 and a second indoor unit gas pipe temperature detection module b2.

[0103] The third indoor unit is provided with a third indoor heat exchanger 18-3, a third indoor expansion valve 19-3 and a third indoor fan (not shown in the figure), and the operating capacity of the third indoor unit can be adjusted by adjusting the opening degree of the third indoor expansion valve 19-3 and / or the rotating speed of the third indoor fan.

[0104] The third indoor unit includes a third indoor environment temperature detection module d3, a third indoor unit liquid pipe temperature detection module c3 and a third indoor unit gas pipe temperature detection module b3.

[0105] The indoor environment temperature detection module is configured to detect the indoor temperature T i .

[0106] All indoor units include a set temperature acquisition module configured to acquire the indoor set temperature T s .

[0107] According to the actual composition of the building load, a load characteristic model is established, and the acquired capacity Q e of the indoor unit is regarded as the actual load Q of the building to learn the building load characteristics and establish a load characteristic model.

[0108] The building load characteristic model can reflect indoor air heat storage load, wall and window heat leakage load, or equipment and personnel internal disturbance load. The air heat storage load is related to the room space size, the difference between the set temperature and the initial temperature. The wall and window heat leakage load is mainly related to the building thermal insulation and the indoor and outdoor temperature difference. The equipment and personnel internal disturbance load is related to the use scenario.

[0109] The learning of the model needs to select a complete cooling process, and the running data in the process is used as historical learning data to determine the cooling load parameters in the load characteristic learning model, and finally form the load characteristic model for the target model building.

[0110] In some embodiments, the load characteristic learning model is represented by the following formula: Q e = Q = a x (T i -T s ) + b x (T a -T i ) x t1 + c x t1

[0111] Wherein, a, b, c are cooling load parameters, T i is the indoor temperature, T s is the set temperature, T a is the outdoor temperature, and t1 is the learning step.

[0112] The learning step t1 is the time interval of the learning data determined in advance, which can be adjusted according to the needs.

[0113] At least 3 time points in the historical learning data are selected with the learning step t1, and the indoor unit historical learning data (Q e(n) , T i(n) , T a(n)， n represents the time point) corresponding to the above time points is brought into the load characteristic learning model to establish an equation to solve the building load characteristic parameters a, b and c.

[0114] The capacity Q e of the indoor unit is a function related to the indoor heat exchanger structure parameters, heat exchange characteristic parameters, superheat degree, subcooling degree and evaporation temperature, which can be calculated by the existing technology: Q e = f (S str , K, SH, SC, T e )

[0115] In the above formula:

[0116] S str : indoor heat exchanger structure parameter;

[0117] K: heat exchange characteristic parameter of indoor heat exchanger in current working condition;

[0118] SH: superheat of indoor heat exchanger outlet, ℃;

[0119] SC: subcooling of indoor heat exchanger inlet, ℃;

[0120] T e : evaporating temperature of indoor heat exchanger, ℃.

[0121] After the load characteristic model is established, the current outdoor environment temperature, indoor temperature and expected indoor temperature can be input into the model to determine the current room demand load, and the system operation parameters are adjusted according to the demand load and control target.

[0122] In a multi-connected system, the cooling load parameters of each indoor unit corresponding to the room need to be determined, so for the jth indoor unit, the building load characteristic learning model is as follows: Q ej = Q j = a j ×(T ij -T sj )+b j ×(T a -T ij )×t1+c j ×t1

[0123] In the above formula:

[0124] Q ej : capacity of the jth indoor unit, kW;

[0125] Q j : building load corresponding to the jth indoor unit, kW;

[0126] a j , b j , c j : cooling load parameters corresponding to the jth indoor unit, dimensionless unit;

[0127] T ij : indoor temperature corresponding to the jth indoor unit, ℃;

[0128] T sj : set temperature corresponding to the jth indoor unit, ℃;

[0129] T a : outdoor temperature, ℃;

[0130] t1: learning time step, min.

[0131] The capacity Q ej of the jth indoor unit is a function related to the indoor unit heat exchanger structure parameters, heat exchange characteristic parameters, superheat, subcooling and evaporating temperature, which can be calculated by existing technology: Q ej = f(Sstrj K j ,SH j ,SC j ,T ej

[0132] In the above formula:

[0133] S strj : the jth indoor heat exchanger structure parameter;

[0134] K j : the jth indoor heat exchanger heat exchange characteristic parameter under the current working condition;

[0135] SH j : the jth indoor heat exchanger outlet superheat, ℃;

[0136] SC j : the jth indoor heat exchanger inlet subcooling, ℃;

[0137] T ej : the jth indoor heat exchanger evaporation temperature, ℃.

[0138] In some embodiments, in order to avoid the first start-up from being unable to self-learn to determine the refrigeration load parameter, it is judged whether the air conditioning system is the first start-up when the air conditioning system is started. If it is the first start-up, the built-in refrigeration load parameters a0, b0 and c0 of the multi-connected machine are read, and the air conditioning system is controlled by using the refrigeration load parameters a0, b0 and c0. If it is not the first start-up, it is necessary to judge whether self-learning is needed for the current operation. When the refrigeration self-learning condition is met, the refrigeration load parameter is determined through self-learning, and the air conditioning system is controlled by using the learned refrigeration load parameter. In the subsequent start-up process, it is judged whether self-learning is needed for the current operation. If not, the refrigeration load parameter determined through the last self-learning is used for control. If so, the refrigeration load parameter is determined through self-learning, and the air conditioning system is controlled by using the learned refrigeration load parameter.

[0139] In the example of FIG. 3, the flow of determining the refrigeration load parameter in the refrigeration mode is as follows:

[0140] S31, start.

[0141] S32, judge whether it is the first start-up. If yes, go to step S33, otherwise, go to step S34.

[0142] S33, read the built-in refrigeration load parameters a0, b0 and c0 of the multi-connected machine as the refrigeration load parameter.

[0143] S34, judge whether the refrigeration self-learning condition is met. If not, go to step S35, if yes, go to step S36.

[0144] ​S35, acquire the refrigeration load parameter of the last running.

[0145] S36, perform self-learning to determine the learned refrigeration load parameter.

[0146] In some embodiments, the self-learning of the refrigeration load parameter is performed when the following two conditions are met:

[0147] Condition 1: no learning has been performed after the current indoor unit is turned on;

[0148] Condition 2: the time length from the last learning end time point is greater than the set time.

[0149] In some embodiments, the self-learning of the refrigeration load parameter is performed when the following three conditions are met:

[0150] Condition 1: no learning has been performed after the current indoor unit is turned on;

[0151] Condition 2: the time length from the last learning end time point is greater than the set time;

[0152] Condition 3: the historical learning data of the indoor unit that can be used for model learning can be acquired.

[0153] The air conditioner refrigeration running process includes several cooling processes. The historical data of a complete cooling process meeting the following standards is used as the historical learning data: the total cooling time length is greater than the set time length Ymin, the absolute value of the initial indoor temperature and outdoor temperature difference of the cooling process is lower than the set temperature difference, the indoor temperature change within a certain time is higher than the first set difference value; the final indoor temperature difference of the cooling process and the set temperature is lower than the second set difference value. The historical data of the cooling process is used as the historical learning data.

[0154] Among them, the temperature change trend in the complete cooling process is downward.

[0155] In the above determined historical learning data, at least 3 time points are selected with a learning step t1. The indoor unit historical learning data (Q e(n) , T i(n) , T a(n)， n represents the time point) corresponding to the above time points is brought into the load feature learning model to establish an equation to solve the building load feature parameters a, b, and c.

[0156] In the example of FIG. 4, the method for acquiring the historical learning data that can be used for model learning includes the following steps:

[0157] S41, start.

[0158] S42, select the indoor unit refrigeration running period to be used for learning, and acquire the running parameters in this period: running time t n , indoor temperature T i, outdoor temperature T a , and set temperature T s .

[0159] S43, determining whether the running time tn is greater than or equal to the set time Y min . If yes, go to step S44, otherwise, go to step S42.

[0160] S44, determining whether the absolute value of the temperature difference between the initial indoor temperature T i(0) and the outdoor temperature T a(0) is lower than or equal to the set temperature difference k, if yes, go to step S45, otherwise, go to step S42.

[0161] S45, determining whether the indoor temperature change within a certain time is higher than the first set difference, if yes, go to step S46, otherwise, go to step S42.

[0162] wherein the first set difference is, for example, 0.5℃.

[0163] S46, determining whether the final indoor temperature is the same as the set temperature, if yes, go to step S47, otherwise, go to step S42.

[0164] S47, taking the indoor temperature T i , outdoor temperature T a , set temperature T s , learning time step t1 and corresponding indoor unit capacity Q e as historical learning data.

[0165] In some embodiments, determining the expected indoor temperature at the current time includes:

[0166] obtaining temperature characteristic constants, initial time indoor temperature, last time indoor temperature and set temperature;

[0167] determining the expected indoor temperature at the current time according to the difference between the initial time indoor temperature, the last time indoor temperature and the set temperature, the difference between the initial time indoor temperature and the set temperature, the time from the initial time to the current time and the temperature characteristic constants.

[0168] In some embodiments, the expected indoor temperature at the current time is determined by the following formula:

[0169] In the above formula: α, β, γ are temperature characteristic constant items, and are constants determined according to the room where the indoor unit is located.

[0170] τ n is the current time value since the beginning of the cooling process, min;

[0171] T exp(n)T

[0172] T i(n-1) T

[0173] T i(0) T

[0174] T s T

[0175] T exp(n) T exp(n) Q

[0176] T i(0) T exp(0) .

[0177] T i T s . exp(n) T s .

[0178] T

[0179] In some embodiments, determining the demand load at the current time according to the refrigeration load parameter, the indoor temperature at the current time, the expected indoor temperature at the current time, the outdoor temperature at the current time, and the control period comprises: determining the demand load at the current time according to the refrigeration load parameter, the difference between the indoor temperature at the current time and the expected indoor temperature at the current time, the difference between the outdoor temperature at the current time and the indoor temperature, and the control period.

[0180] After confirming the refrigeration load parameters a, b, and c and the expected indoor temperature T exp(n) at the current time, the demand load Q r(n) of the target indoor unit at the current time is calculated based on the following demand load model: Q r(n) = a × (T i(n) - T exp(n) ) + b × (T a(n) - T i(n) ) × t2 + c × t2

[0181] In the above formula:

[0182] Q r(n) : demand load at the n th moment, kW;

[0183] a, b, c: refrigeration load parameters, dimensionless;

[0184] T i(n) : indoor temperature at the n th moment, ℃;

[0185] T exp(n) : expected indoor temperature at the n th moment, ℃;

[0186] T a(n) : outdoor environment temperature at the n th moment, ℃;

[0187] t2: control period, min.

[0188] In the example of FIG. 5, the method for determining the demand load at the current moment includes the following steps:

[0189] S51, start.

[0190] S52, determine the refrigeration load parameters a, b, and c of the room corresponding to the indoor unit.

[0191] S53, determine the expected indoor temperature T exp(n) at the current moment according to the expected indoor temperature calculation formula.

[0192] S54, determine the demand load Q r(n) at the current moment according to the refrigeration load parameters a, b, and c, the difference between the indoor temperature T i(n) at the current moment and the current expected indoor temperature T exp(n) , the difference between the outdoor temperature T a(n) at the current moment and the indoor temperature T i(n) at the current moment, and the control period.

[0193] Determining the demand load according to the refrigeration load parameters, the difference between the indoor temperature and the expected indoor temperature, and the difference between the outdoor temperature and the indoor temperature can improve the accuracy of the determination of the demand load at the current moment.

[0194] The operating parameters of the air conditioning system mainly include the compressor frequency and the indoor unit air damper.

[0195] The control of the compressor frequency includes the control of the compressor frequency at the initial moment and the real-time control of the compressor frequency.

[0196] In some embodiments, the operating parameters include the compressor frequency at the initial moment, and the method for determining the compressor frequency at the initial moment includes the following steps:

[0197] Obtain the compressor characteristic parameters S;

[0198] determining the demand load Q at the initial moment r(0) ;

[0199] determining the compressor frequency H0 at the initial moment according to the compressor characteristic parameter S, the demand load Q at the initial moment and the control period t. r(0)

[0200] determining the compressor frequency at the initial moment according to the demand load at the initial moment, so that the compressor frequency at the initial moment meets the demand load requirement at the initial moment, and realizing the rapid cooling at the initial stage of refrigeration.

[0201] the demand load at the initial moment: Q r(0) = a × (T i(0) - T exp(0) ) + b × (T a(0) - T i(0) ) × t2 + c × t2

[0202] the initial frequency of the compressor:

[0203] In the above formula:

[0204] S: compressor characteristic parameter, constant, related to the compressor specification;

[0205] t2: control period length, min;

[0206] x: constant, for example: 2.8.

[0207] In a multi-split system, the demand load Q at the initial moment r(0) is the sum of the demand loads of all the indoor units at the initial moment. That is:

[0208] the initial frequency of the compressor:

[0209] In the above formula:

[0210] S: compressor characteristic parameter, constant, related to the compressor specification;

[0211] g: the number of indoor units that are turned on;

[0212] Q rj(0) : the demand load at the initial moment of the jth indoor unit of the air conditioning system that is turned on, it should be noted that when Q rj(0)

[0213] <0, the value is 0;

[0214] T ij(0) : the indoor temperature at the initial moment of the jth indoor unit of the air conditioning system that is turned on, ℃;​

[0215] T expj(0) : expected indoor temperature of the jth indoor unit of the air conditioning system at the initial time of starting, ℃;

[0216] T a(0) : outdoor environment temperature at the initial time of starting of the air conditioning system, ℃;

[0217] t2: control period length, min;

[0218] x: constant, for example: 2.8.

[0219] The target frequency of the compressor at the initial time is the initial frequency of the compressor.

[0220] In the example of FIG. 6, the method for determining the initial frequency of the compressor includes the following steps:

[0221] S61, start.

[0222] S62, obtain the control period, the refrigeration load parameters of all the indoor units in the system, the indoor temperature at the initial time, the outdoor temperature, and the expected indoor temperature.

[0223] S63, calculate the required load of each indoor unit at the initial time according to the control period, the refrigeration load parameters of each indoor unit, the indoor temperature at the initial time, the outdoor temperature, and the expected indoor temperature.

[0224] S64, calculate the required load of all the indoor units at the initial time.

[0225] The required load of all the indoor units at the initial time is the sum of the required load of each indoor unit at the initial time.

[0226] S65, obtain the compressor characteristic parameters.

[0227] S66, determine the initial frequency of the compressor according to the compressor characteristic parameters, the required load of all the indoor units at the initial time, and the control period.

[0228] The operating parameters include the current frequency of the compressor, and determining the current frequency of the compressor according to the current required load includes:

[0229] obtain the actual evaporating temperature of the indoor unit at the current time;

[0230] determine the target evaporating temperature of the indoor unit at the current time according to the current required load and the current indoor temperature;

[0231] obtain the frequency of the compressor at the previous time, the actual evaporating temperature of the indoor unit at the previous time, and the target evaporating temperature at the previous time;

[0232] The compressor frequency at the current time is determined according to the difference between the actual evaporating temperature of the indoor unit at the previous time and the target evaporating temperature at the previous time, the difference between the actual evaporating temperature of the indoor unit at the current time and the target evaporating temperature at the current time, and the compressor frequency at the previous time.

[0233] The air conditioning system determines the demand load at the current time, determines the target evaporating temperature according to the demand load at the current time, and determines the compressor frequency at the current time according to the difference between the actual evaporating temperature at the current time and the target evaporating temperature, the difference between the actual evaporating temperature at the previous time and the target evaporating temperature, and the compressor frequency at the previous time. Thus, the air conditioning system determines the compressor operating frequency at the current time according to the demand load change and the compressor frequency at the previous time to realize load following control, so that the operating capacity of the air conditioning system matches the demand load to realize smooth adjustment of the compressor frequency.

[0234] In some embodiments, determining the compressor frequency at the current time according to the difference between the actual evaporating temperature of the indoor unit at the previous time and the target evaporating temperature at the previous time, the difference between the actual evaporating temperature of the indoor unit at the current time and the target evaporating temperature at the current time, and the compressor frequency at the previous time comprises:

[0235] Obtaining a compressor characteristic parameter S, a compressor iterative correction coefficient m1 and m2;

[0236] The compressor frequency at the current time is calculated based on the following formula:

[0237] The compressor characteristic parameter S is a constant and is related to the compressor specification;

[0238] The compressor iterative correction coefficients m1 and m2 are constants and are related to the compressor specification;

[0239] H (n) is the compressor frequency at the current time;

[0240] H (n-1) is the compressor frequency at the previous time;

[0241] ΔT ep(n) is the difference between the actual evaporating temperature of the indoor unit at the current time and the target evaporating temperature;

[0242] ΔT ep(n-1) is the difference between the actual evaporating temperature of the indoor unit at the previous time and the target evaporating temperature.

[0243] The compressor frequency is corrected by the compressor characteristic parameter S, the compressor iterative correction coefficient m1 and the compressor iterative correction coefficient m2 to improve the accuracy of the determination of the compressor frequency.

[0244] In some embodiments, determining the target evaporating temperature of the indoor unit at the current time according to the demand load at the current time and the indoor temperature at the current time comprises: obtaining a model characteristic parameter of the indoor unit, and determining the target evaporating temperature of the indoor unit at the current time according to the indoor temperature at the current time, the demand load at the current time, the model characteristic parameter of the indoor unit, and a control period.

[0245] The target evaporating temperature at the current time is calculated as follows:

[0246] wherein, T eo is the target evaporating temperature at the current time;

[0247] T i(n) is the indoor temperature at the current time;

[0248] ζ HP is the model characteristic parameter of the indoor unit; the parameter is only related to the specification of the indoor unit and has no dimension unit;

[0249] Q r(n) is the demand load at the current time;

[0250] t2 is the length of the control period.

[0251] The target evaporating temperature at the current time is determined according to the demand load at the current time, so as to further control the frequency of the compressor.

[0252] For a multi-split system, for example, when multiple indoor units are turned on, the minimum value of the target evaporating temperature at the current time of the multiple indoor units is determined as the target evaporating temperature at the current time, and the average value of the actual evaporating temperature at the current time of the multiple indoor units is taken as the actual evaporating temperature.

[0253] The minimum value of the target evaporating temperature of all the turned-on indoor units is taken as the target evaporating temperature, so that the determined frequency of the compressor can meet the demand load; the average value of the actual evaporating temperature at the current time of the multiple indoor units is taken as the actual evaporating temperature, which can more accurately reflect the actual evaporating temperature of the multi-split system.

[0254] The determination method of the target evaporating temperature at the current time of the multi-split system is as follows:

[0255] According to the above method, the demand load Q rj(n) of each turned-on indoor unit j at the current time n is calculated, and the target evaporating temperature of each indoor unit j at the current time n is calculated as follows:

[0256] In the above formula,

[0257] T ij(n) : the indoor temperature of the jth indoor unit at the nth time, ℃;

[0258] ζ HP_j : model characteristic parameter of the jth indoor unit, which is only related to the specification of the indoor unit, and is dimensionless;

[0259] t: control cycle length of the air conditioning system, h.

[0260] target evaporating temperature of the air conditioning system at the current time T eo(n) is the minimum value of the target evaporating temperature of all indoor units in the system at the current time.

[0261] average value of the actual evaporating temperature of the indoor units in the system at the current time T lave(n) .

[0262] compressor frequency at the current time (i.e., the nth time) H (n) : ΔT ep(n) = T lave(n) - T eo(n)

[0263] In the above formula:

[0264] T lave(n) : average value of the actual evaporating temperature of the indoor units in the system at the current time, ℃;

[0265] m1, m2: compressor frequency iterative correction coefficients, constants;

[0266] S: compressor characteristic parameter, constant, related to the specification of the compressor;

[0267] ΔT ep(n-1) can be calculated according to the calculation formula of ΔT ep(n) .

[0268] In the example of FIG. 7, the control method of the compressor at the current time is as follows:

[0269] S71, start.

[0270] S72, obtain the actual evaporating temperature of the indoor unit at the current time.

[0271] When multiple indoor units are turned on, the average value of the actual evaporating temperature of the multiple indoor units at the current time is taken as the actual evaporating temperature.

[0272] S73, determine the target evaporating temperature of the indoor unit at the current time according to the required load and indoor temperature at the current time.

[0273] When multiple indoor units are turned on, the minimum value of the target evaporating temperature of the multiple indoor units at the current time is determined as the target evaporating temperature at the current time.

[0274] S74, calculate the difference between the actual evaporating temperature of the indoor unit at the current time and the target evaporating temperature.

[0275] S75, obtain the compressor frequency, the actual evaporating temperature of the indoor unit and the target evaporating temperature at the previous time; obtain the compressor characteristic parameter S, the compressor iteration correction coefficient m and the compressor iteration correction coefficient n.

[0276] S76, calculate the compressor frequency at the current time.

[0277] The indoor unit air volume at the current time is determined according to the demand load at the current time, which includes:

[0278] Obtain the capacity characteristic coefficient of the indoor unit and the demand load at the current time, determine the compressor frequency correction coefficient according to the demand load at the current time, the capacity characteristic coefficient of the indoor unit and the control period, determine the indoor unit air volume according to the compressor frequency correction coefficient, and the indoor fan air volume is positively correlated with the compressor frequency correction coefficient.

[0279] In some embodiments, upon receiving the determined air volume control signal, the indoor fan air volume is controlled to operate according to the determined air volume;

[0280] When the determined air volume control signal is not received, the indoor unit air volume is determined according to the compressor frequency correction coefficient, and the indoor fan air volume is positively correlated with the compressor frequency correction coefficient.

[0281] The determination method of the compressor frequency correction coefficient includes:

[0282] Obtain the capacity characteristic coefficient of the indoor unit and the demand load at the current time, determine the compressor frequency correction coefficient according to the demand load at the current time, the capacity characteristic coefficient of the indoor unit and the control period, and the indoor fan air volume is positively correlated with the compressor frequency correction coefficient.

[0283] In the above formula:

[0284] K comp(n) : the compressor frequency correction coefficient at the nth time, it should be noted that when the calculation result K comp(n) < 0, the value is 0;

[0285] V HP : the capacity characteristic coefficient of the indoor unit, a constant, related to the capacity and specification of the indoor unit;

[0286] x: a constant, for example: 2.8.

[0287] The indoor fan air volume is adjusted according to the demand load at the current time to further ensure that the capacity of the indoor unit meets the demand load.

[0288] The control of the initial air volume of the indoor fan includes:

[0289] When the determined wind control signal is not received, the initial wind level F0 of the indoor fan is corrected according to the initial compressor frequency correction coefficient K comp(0) The initial wind level F0 of the indoor fan is determined according to the initial compressor frequency correction coefficient K comp(0) The initial wind level F0 of the indoor fan is determined according to the initial compressor frequency correction coefficient K

[0290] The initial compressor frequency correction coefficient K is determined according to the initial wind level F0 of the indoor fan

[0291] At the initial time, the initial wind level F0 of the indoor fan is set according to the application or running state of the air conditioning system. If the user sets a determined wind level, the initial wind level F0 uses the determined wind level set by the user. If the user sets a free wind level or does not set a wind level, in some embodiments, the initial wind level F0 is set according to the following table:

[0292] The indoor fan includes 6 levels, and the initial wind level F0 of the indoor fan is determined according to the initial K comp(0) value.

[0293] In the example of FIG. 8, the determination method of the initial wind level of the indoor fan is as follows:

[0294] S81, start.

[0295] S82, determine whether the user sets a determined wind level. If yes, go to step S3, otherwise go to step S4.

[0296] S83, run according to the determined wind level set by the user.

[0297] S84, determine the initial compressor frequency correction coefficient K comp(0) .

[0298] S85, determine the initial wind level of the indoor fan corresponding to the initial compressor frequency correction coefficient.

[0299] Real-time control of the indoor fan level:

[0300] The real-time wind level of the indoor fan is determined according to the real-time compressor frequency correction coefficient, and the real-time wind level of the indoor fan is positively correlated with the real-time compressor frequency correction coefficient.

[0301] In a multi-split system, the compressor frequency correction coefficient corresponding to the jth indoor unit at the current time (n) is:

[0302] Q rj(n) : the demand load of the jth indoor unit at the current time when the air conditioning system is started;

[0303] V HPj : the capacity characteristic coefficient of the jth indoor unit in the system, which is a constant and is related to the capacity and size of the indoor unit;

[0304] T expj(n) is the expected indoor temperature of the jth indoor unit at the current time, ℃;

[0305] T ij(n) is the indoor temperature corresponding to the jth indoor unit at the current time, ℃;

[0306] T a(n) is the outdoor temperature at the current time, ℃.

[0307] In some embodiments, the current time jth indoor unit air damper is set according to the following table:

[0308] The indoor fan includes 6 gears, according to the real-time K compj(n) value to determine whether the air damper needs to be changed at the current time to meet the actual demand of the indoor unit.

[0309] In the example of FIG. 9, the control method of the current time indoor unit air damper includes the following steps:

[0310] S91, start.

[0311] S92, determine the current time compressor frequency correction coefficient.

[0312] S93, determine the current time indoor fan air damper corresponding to the current time compressor frequency correction coefficient.

[0313] S94, control the indoor unit air damper to the current time indoor unit air damper.

[0314] In some embodiments, steps S2-S4 are repeatedly executed at a certain time period.

[0315] The operating parameters of the air conditioning system also include the indoor expansion valve opening degree, which is controlled in relation to the real-time superheat value of the indoor unit, which is detected and calculated under the above demand load control method.

[0316] In some embodiments, the control method of the indoor expansion valve opening degree includes: determining the real-time superheat value of the indoor unit, when the real-time superheat value is below the set value, the indoor expansion valve opening degree remains unchanged, and when the real-time superheat value is above the set value, the indoor expansion valve opening degree is increased.

[0317] In some embodiments, the set value is 0.

[0318] Determine the superheat value SH j of the jth indoor unit, if the superheat value SH j ≤ 0, the indoor expansion valve opening degree value EXV j remains unchanged; if the superheat value SHj If the value is greater than 0, then increase the electronic expansion valve opening degree EXV of the indoor unit j .

[0319] By adjusting the indoor expansion valve opening degree to ensure that the real-time superheat is below the set value, the normal operation of the compressor and the evaporation capacity of the indoor unit are ensured.

[0320] In some embodiments, the method for determining the amount of increase in the indoor expansion valve opening degree comprises the following steps:

[0321] Obtaining a superheat iterative correction coefficient;

[0322] Calculating the difference between the current time and the previous time superheat as a first difference;

[0323] Calculating the difference between the previous time and the time before that superheat as a second difference;

[0324] Determining the amount of increase in the indoor expansion valve opening degree according to the first difference, the difference between the first difference and the second difference, and the superheat correction coefficient.

[0325] The determination method of the amount of increase in the indoor expansion valve opening degree can ensure smooth adjustment of the indoor expansion valve opening degree.

[0326] In some embodiments, the previous time indoor expansion valve opening degree of the jth indoor unit is EXV j(n-1) , and the calculation method of the current time indoor expansion valve opening degree EXV j(n) is as follows: ΔSH j(n) = SH j(n) - SH j(n-1)

[0327] In the above formula, r1, r2, C SH : superheat iterative correction coefficient, constant, related to the specifications of the indoor unit;

[0328] SH j(n) : the superheat at the outlet of the jth indoor unit at the nth time;

[0329] SH j(n-1) : the superheat at the outlet of the jth indoor unit at the n-1th time;

[0330] ΔSH j(n-1) can be calculated according to the calculation formula of ΔSH j(n) .

[0331] In the example of FIG. 10, the control method of the indoor expansion valve is as follows:

[0332] S101, start.

[0333] S102, control the indoor expansion valve to the initial opening degree.

[0334] S103, calculating the superheat value SH of the indoor unit i .

[0335] S104, judging whether the superheat value SH is less than or equal to 0, if yes, entering step S105, otherwise, entering step S106. i

[0336] S105, keeping the indoor expansion valve opening unchanged. Entering step S103.

[0337] S106, increasing the indoor expansion valve opening. Entering step S103.

[0338] In the multi-split system, the initial opening of the current indoor expansion valve is determined according to the maximum opening of the current indoor expansion valve, the ratio of the capacity value of the current operating indoor unit to the sum of the capacities of all operating indoor units.

[0339] The initial opening of the indoor expansion valve determined in the above manner makes the refrigerant distribution more reasonable.

[0340] In some embodiments, the control of the initial opening of the indoor expansion valve is as follows:

[0341] The initial opening of the indoor expansion valve of the jth indoor unit is:

[0342] In the above formula:

[0343] EXV maxj : the maximum opening value of the jth indoor expansion valve;

[0344] VO j : the capacity value of the jth indoor unit, HP;

[0345] the sum of the capacities of the operating indoor units in the system, HP;

[0346] C b : a mode correction parameter, a dimensionless parameter, related to a specific function selection item.

[0347] The opening of the indoor expansion valve is adjusted to the initial opening of the indoor expansion valve as described above when the air conditioning system starts.

[0348] The air conditioning system learns the load characteristics of the target building according to the capacity calculation algorithm of the indoor unit operation, establishes a load model after obtaining the load characteristic parameters of the target building, takes the building demand load as the control target of the control system, and obtains the initial control parameters of the air conditioning system in the refrigeration working condition and the control parameters of the load following control process according to the demand load.

[0349] ​Firstly, initial control parameters of the air conditioning system are determined, and then the control parameters of the current time are adjusted according to the real-time demand load and the control parameters of the previous time of the multi-connected air conditioner, so as to realize rapid cooling in the initial stage of the cooling process, improve the comfort, and reduce the room temperature fluctuation in the small load to avoid the increase of power consumption caused by frequent start and stop.

[0350] The control method for adjusting the compressor, the expansion valve and the damper based on the actual demand load of the building can match the air conditioning capacity with the actual load of the building, and solve the problems of overplay and underplay of the indoor unit capacity.

[0351] In the description of the above-described embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0352] The above merely describes specific implementations of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A control method of an air conditioning system, comprising: determining a cooling load parameter of a room corresponding to an indoor unit based on historical learning data and a load feature learning model; the historical learning data comprising indoor temperature, set temperature, outdoor temperature and capacity of the indoor unit corresponding to a plurality of historical time instants; obtaining the indoor temperature at a current time instant and the outdoor temperature at the current time instant; determining a desired indoor temperature at the current time instant; determining a required load at the current time instant according to the cooling load parameter, the indoor temperature at the current time instant, the desired indoor temperature at the current time instant, the outdoor temperature at the current time instant and a control period; determining an operating parameter of the air conditioning system according to the required load at the current time instant. 2.The control method of the air conditioning system according to claim 1, wherein: the load feature learning model is represented by the following formula: Q e = a x (T i - T s ) + b x (T a - T i ) x t1 + c x t1 Wherein, Q e is the capacity of the indoor unit; a, b, c are refrigeration load parameters; T i is the indoor temperature; T s is the set temperature; T a is the outdoor temperature; t1 is the learning step length; the determination of the required load at the current time instant according to the cooling load parameter, the indoor temperature at the current time instant, the desired indoor temperature at the current time instant, the outdoor temperature at the current time instant and the control period comprises determining the required load at the current time instant based on the following formula: Q r(n) = a x (T i(n) - T exp(n) ) + b x (T a(n) - T i(n) ) x t2+ c x t2 wherein Q r(n) is the demand load at the current time; T i(n) is the indoor temperature at the current time; T exp(n) is the desired indoor temperature; T a(n) is the outdoor temperature at the current time; T i(n) is the indoor temperature; and t2 is the control period.

3. The control method of an air conditioning system according to claim 1, wherein, the determination of the desired indoor temperature at the current time instant comprises: obtaining a temperature feature constant, an initial time instant indoor temperature, a last time instant indoor temperature and a set temperature; determining the desired indoor temperature at the current time instant according to the difference between the initial time instant indoor temperature and the set temperature, the difference between the last time instant indoor temperature and the set temperature, the time from the initial time instant to the current time instant and the temperature feature constant. 4.The control method of the air conditioning system according to any one of claims 1-3, wherein: the operating parameter comprises a compressor frequency at the current time instant, and the determination of the compressor frequency at the current time instant according to the required load at the current time instant comprises: obtaining an actual evaporating temperature of the indoor unit at the current time instant; determining a target evaporating temperature of the indoor unit at the current time instant according to the required load at the current time instant and the indoor temperature at the current time instant; obtaining a compressor frequency at a last time instant, an actual evaporating temperature of the indoor unit at the last time instant and a target evaporating temperature at the last time instant; determining the compressor frequency at the current time instant according to the difference between the actual evaporating temperature of the indoor unit at the last time instant and the target evaporating temperature at the last time instant, the difference between the actual evaporating temperature of the indoor unit at the current time instant and the target evaporating temperature at the current time instant and the compressor frequency at the last time instant. 5.The control method of the air conditioning system according to claim 4, wherein: the determination of the compressor frequency at the current time instant according to the difference between the actual evaporating temperature of the indoor unit at the last time instant and the target evaporating temperature at the last time instant, the difference between the actual evaporating temperature of the indoor unit at the current time instant and the target evaporating temperature at the current time instant and the compressor frequency at the last time instant comprises: obtaining a compressor feature parameter S, compressor iteration correction coefficients m1 and m2. The compressor frequency at the current time instant is calculated based on the following equation: H (n) is the compressor frequency at the current time instant; H (n-1) fcomp is the compressor frequency of the previous time instant; ΔT ep(n) ΔT is the difference between the actual indoor unit evaporation temperature at the current time and the target evaporation temperature; ΔT ep(n-1) ΔT is the difference between the actual indoor unit evaporating temperature at the previous time and the target evaporating temperature. 6.The control method of the air conditioning system according to claim 4, wherein: The determining of the target evaporating temperature of the indoor unit at the current time according to the demand load at the current time and the indoor temperature at the current time comprises: obtaining a model characteristic parameter of the indoor unit, and determining the target evaporating temperature of the indoor unit at the current time according to the indoor temperature at the current time, the demand load at the current time, the model characteristic parameter of the indoor unit and the control period.

7. The control method of an air conditioning system according to claim 6, wherein, When the air conditioning system comprises multiple indoor units, the minimum of the target evaporating temperatures of the multiple indoor units at the current time is determined as the target evaporating temperature at the current time, and the average of the actual evaporating temperatures of the multiple indoor units at the current time is determined as the actual evaporating temperature.

8. The control method of the air conditioning system according to any one of claims 1-3, wherein the operating parameter comprises a compressor frequency at an initial time, and the determining of the compressor frequency at the initial time according to the demand load at the initial time comprises: obtaining a compressor characteristic parameter; determining the demand load at the initial time; and determining the compressor frequency at the initial time according to the compressor characteristic parameter, the demand load at the initial time and the control period.

9. The control method of the air conditioning system according to any one of claims 1-3, wherein the operating parameter comprises an indoor unit air volume damper, and the determining of the indoor unit air volume damper at the current time according to the demand load at the current time comprises: obtaining a capacity characteristic coefficient of the indoor unit and the demand load at the current time, determining a compressor frequency correction coefficient according to the demand load at the current time, the capacity characteristic coefficient of the indoor unit and the control period, and determining the indoor unit air volume damper according to the compressor frequency correction coefficient, wherein the indoor unit air volume damper is positively correlated with the compressor frequency correction coefficient. The air conditioning system comprises an indoor expansion valve, and the control method of the indoor expansion valve comprises: determining a real-time superheat value of the indoor unit, wherein when the real-time superheat value is below a set value, the opening degree of the indoor expansion valve remains unchanged, and when the real-time superheat value is above the set value, the opening degree of the indoor expansion valve is increased, and the determination method of the amount of increase of the opening degree of the indoor expansion valve comprises: obtaining a superheat iterative correction coefficient; 10. The control method of the air conditioning system according to any one of claims 1 to 3, wherein, calculating a difference between the superheat at the current time and the superheat at a previous time as a first difference; calculating a difference between the superheat at the previous time and the superheat at a time before the previous time as a second difference; determining the amount of increase of the opening degree of the indoor expansion valve according to the first difference, a difference between the first difference and the second difference, and the superheat iterative correction coefficient. ​ ​

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