Multi-connected air conditioning system and expansion valve opening degree control method and control device thereof

Abstract

The application discloses a multi-connected air conditioner system and an expansion valve opening degree control method and device thereof. The method comprises the following steps: when a single indoor unit is in a refrigeration operation and a minimum opening degree operation condition is met, it is judged whether the running indoor unit has an adjusted minimum opening degree; if the running indoor unit has the adjusted minimum opening degree, the expansion valve of the running indoor unit is controlled based on the adjusted minimum opening degree; if the running indoor unit does not have the adjusted minimum opening degree, the initial minimum opening degree of the running indoor unit is obtained, the initial minimum opening degree is adjusted when the current superheat degree of the air conditioner system is less than the target superheat degree, the adjusted minimum opening degree is obtained, and the expansion valve of the running indoor unit is controlled based on the adjusted minimum opening degree. The application can improve the energy saving and safety of system operation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of air conditioning, in particular, relates to a multi-connected air conditioning system, more particularly, relates to a multi-connected air conditioning system and an expansion valve opening degree control method and control device thereof. BACKGROUND

[0002] The multi-connected air conditioning system usually comprises multiple indoor units, and the refrigerant pipelines of the multiple indoor units are connected in parallel and share one or more outdoor units. In the multi-connected system, an expansion valve is arranged between the heat exchanger of each indoor unit and the heat exchanger of the outdoor unit as a throttling device to throttle the liquid refrigerant at a medium temperature and high pressure into liquid refrigerant at a low temperature and low pressure and provide the heat exchanger as an evaporator.

[0003] The expansion valve is unstable at a low opening degree, and therefore, a fixed minimum opening degree is usually set for the expansion valve when it is shipped from the factory, and the minimum opening degree is used as the lower limit of the expansion valve opening degree adjustment range when the air conditioning system is running. In the multi-connected air conditioning system, the minimum opening degree of each indoor unit is affected by the indoor units and pipelines in the entire multi-connected air conditioning system, and the fixed minimum opening degree may not be appropriate in different air conditioning systems, different operating environments and operating states. If the fixed minimum opening degree is too large, the air conditioning system has a risk of liquid return, and the energy consumption is high; if the fixed minimum opening degree is too small, the expansion valve is easily closed, which causes the refrigerant to be unable to flow, thereby causing the air conditioning system to fail. SUMMARY

[0004] One of the purposes of the present application is to provide a control method and control device for the expansion valve opening degree of a multi-connected air conditioning system to improve the energy saving and safety of system operation.

[0005] To achieve the above-mentioned purposes, the control method for the expansion valve opening degree of the multi-connected air conditioning system provided by the present application adopts the following technical scheme:

[0006] A control method for the expansion valve opening degree of a multi-connected air conditioning system, comprising:

[0007] When a single indoor unit is in refrigeration operation and the minimum opening degree operation condition is met, it is determined whether the running indoor unit has an adjusted minimum opening degree;

[0008] If the running indoor unit has the adjusted minimum opening degree, the expansion valve of the running indoor unit is controlled based on the adjusted minimum opening degree;

[0009] If the running indoor unit does not have the adjusted minimum opening degree, the initial minimum opening degree of the running indoor unit is obtained, the initial minimum opening degree is adjusted when the current superheat degree of the air conditioning system is less than the target superheat degree to obtain the adjusted minimum opening degree, and the expansion valve of the running indoor unit is controlled based on the adjusted minimum opening degree.

[0010] In some embodiments of the present application, when the current superheat degree of the air conditioning system is less than the target superheat degree, the initial minimum opening degree is adjusted to obtain an adjusted minimum opening degree, comprising:

[0011] The initial minimum opening degree is reduced at a set rate to obtain an initial adjusted minimum opening degree;

[0012] The expansion valve of the operating indoor unit is controlled according to the initial adjusted minimum opening degree until the current superheat degree is not less than the target superheat degree;

[0013] The initial adjusted minimum opening degree when the current superheat degree is not less than the target superheat degree is determined as the adjusted minimum opening degree.

[0014] In some embodiments of the present application, when the current superheat degree of the air conditioning system is less than the target superheat degree, the initial minimum opening degree is adjusted to obtain an adjusted minimum opening degree, comprising:

[0015] Step a, the initial minimum opening degree is reduced at a set rate to obtain an initial adjusted minimum opening degree;

[0016] Step b, the expansion valve of the operating indoor unit is controlled according to the initial adjusted minimum opening degree until the current superheat degree is not less than the target superheat degree, and the initial adjusted minimum opening degree when the current superheat degree is not less than the target superheat degree is recorded;

[0017] Step c, when the number of recorded initial adjusted minimum opening degrees does not reach a set number, the current initial adjusted minimum opening degree is increased as a new initial minimum opening degree;

[0018] Then, the step a, the step b and the step c are continuously executed until the number of recorded initial adjusted minimum opening degrees reaches the set number;

[0019] Step d, the adjusted minimum opening degree is determined according to all the recorded initial adjusted minimum opening degrees.

[0020] In some embodiments of the present application, the method further comprises:

[0021] If the operating indoor unit does not have the adjusted minimum opening degree, the initial minimum opening degree of the operating indoor unit is obtained, and the expansion valve of the operating indoor unit is controlled based on the initial minimum opening degree when the current superheat degree of the air conditioning system is not less than the target superheat degree.

[0022] In some embodiments of the present application, the method further comprises:

[0023] If the operating indoor unit has the adjusted minimum opening degree, it is judged whether the current state of the air conditioning system meets a preset re-adjustment condition;

[0024] If the preset readjustment condition is met, the expansion valve of the running indoor unit is controlled based on the readjusted minimum opening degree when the current superheat degree of the air conditioning system is less than the target superheat degree.

[0025] If the preset readjustment condition is not met, the expansion valve of the running indoor unit is controlled based on the adjusted minimum opening degree.

[0026] To achieve the above-mentioned purposes, the control device for the minimum opening degree of the expansion valve of the multi-connected air conditioning system provided by the application is implemented by using the following technical solutions:

[0027] The control device for the minimum opening degree of the expansion valve of the multi-connected air conditioning system comprises:

[0028] An adjusted minimum opening degree judging unit is configured to judge whether the running indoor unit has an adjusted minimum opening degree when a single indoor unit is in cooling operation and the minimum opening degree operation condition is met.

[0029] An minimum opening degree adjusting unit is configured to obtain an initial minimum opening degree of the running indoor unit when the running indoor unit does not have the adjusted minimum opening degree, and adjust the initial minimum opening degree to obtain the adjusted minimum opening degree when the current superheat degree of the air conditioning system is less than the target superheat degree.

[0030] An expansion valve control unit is configured to control the expansion valve of the running indoor unit based on the adjusted minimum opening degree.

[0031] In some embodiments of the application, the minimum opening degree adjusting unit comprises:

[0032] An initial adjustment minimum opening degree obtaining subunit is configured to decrease the initial minimum opening degree at a set rate to obtain an initial adjustment minimum opening degree.

[0033] An adjusted minimum opening degree determining subunit is configured to determine the initial adjustment minimum opening degree when the current superheat degree is not less than the target superheat degree as the adjusted minimum opening degree.

[0034] The expansion valve control unit is further configured to control the expansion valve of the running indoor unit according to the initial adjustment minimum opening degree.

[0035] In some embodiments of the application, the minimum opening degree adjusting unit comprises:

[0036] An initial adjustment minimum opening degree obtaining subunit is configured to decrease the initial minimum opening degree at a set rate to obtain an initial adjustment minimum opening degree.

[0037] A primary minimum opening degree recording subunit is configured to record a primary minimum opening degree when the current superheat degree is not less than the target superheat degree during control of the expansion valve of the operating indoor unit by the expansion valve control unit according to the primary minimum opening degree;

[0038] A primary minimum opening degree number determining subunit is configured to determine whether the number of the recorded primary minimum opening degrees reaches a set number;

[0039] A primary minimum opening degree updating subunit is configured to increase the current primary minimum opening degree as a new initial minimum opening degree when the number of the recorded primary minimum opening degrees does not reach the set number.

[0040] An adjusted minimum opening degree determining subunit is configured to determine the adjusted minimum opening degree according to all the recorded primary minimum opening degrees when the number of the recorded primary minimum opening degrees reaches the set number.

[0041] In some embodiments of the present application, the device further comprises:

[0042] A re-adjustment condition judging subunit is configured to judge whether a current state of the air conditioning system meets a preset re-adjustment condition when the operating indoor unit has the adjusted minimum opening degree.

[0043] The minimum opening degree adjusting subunit is further configured to re-adjust according to the initial minimum opening degree to obtain a re-adjusted minimum opening degree when the current state meets the preset re-adjustment condition and the current superheat degree of the air conditioning system is less than the target superheat degree.

[0044] The expansion valve control unit is further configured to control the expansion valve of the operating indoor unit based on the re-adjusted minimum opening degree.

[0045] Another purpose of the present application is to provide a multi-split air conditioning system comprising a plurality of indoor units, each of which corresponds to an expansion valve, and the multi-split air conditioning system further comprises the above-mentioned control device of the expansion valve opening degree.

[0046] Compared with the prior art, the present application has the following advantages and positive effects:

[0047] The application provides a control method for the opening degree of an expansion valve of a multi-connected air conditioning system, when a single indoor unit is in a refrigeration operation and a minimum opening degree operation condition is met, first, it is judged whether the running indoor unit has an adjusted minimum opening degree, if not, the initial minimum opening degree is adjusted, so that the expansion valve of the running indoor unit is in an adjusted minimum opening degree operation; the adjusted minimum opening degree is adaptively adjusted according to the actual situation of each indoor unit, and is more in line with the operation environment and operation state of the indoor unit itself, so that the problem of too large or too small minimum opening degree of the indoor unit caused by the use of a fixed minimum opening degree of all indoor units can be avoided, and the energy saving, safety and stability of the whole multi-connected air conditioning system are improved; moreover, the initial minimum opening degree is not adjusted in all working conditions, but is adjusted when the current superheat is less than the target superheat, so that the rationality of the minimum opening degree adjustment time and the effectiveness of the adjustment are improved, and the instability of the air conditioning system caused by excessive adjustment is avoided.

[0048] Other features and advantages of the present application will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described in the following are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0050] Figure 1 The flow chart of the first embodiment of the control method for the opening degree of the expansion valve of the multi-connected air conditioning system of the present application;

[0051] Figure 2 The flow chart of the second embodiment of the control method for the opening degree of the expansion valve of the multi-connected air conditioning system of the present application;

[0052] Figure 3 The flow chart of the third embodiment of the control method for the opening degree of the expansion valve of the multi-connected air conditioning system of the present application;

[0053] Figure 4 The flow chart of the fourth embodiment of the control method for the opening degree of the expansion valve of the multi-connected air conditioning system of the present application;

[0054] Figure 5 The structural schematic block diagram of the first embodiment of the control device for the opening degree of the expansion valve of the multi-connected air conditioning system of the present application;

[0055] Figure 6 The structural schematic block diagram of the second embodiment of the control device for the opening degree of the expansion valve of the multi-connected air conditioning system of the present application;

[0056] Figure 7 Fig. 3 is a structural schematic block diagram of a third embodiment of the control device for the expansion valve opening degree of the multi-connected air conditioning system according to the present application. DETAILED DESCRIPTION

[0057] In order to make the objectives, technical solutions, and advantages of the present application clearer, further detailed description will be given below in combination with the accompanying drawings and examples.

[0058] It should be noted that the technical solutions of various embodiments of the present application can be combined with each other, but it must be based on the fact that they can be realized by ordinary skilled in the art. When the combination of technical solutions appears to be contradictory or unachievable, it should be considered that such combination of technical solutions does not exist and is not within the protection scope claimed by the present application.

[0059] In the existing multi-connected air conditioning system, the minimum opening degree of the expansion valve of each indoor unit is usually a fixed value. The minimum opening degree is affected by the indoor units and pipelines in the entire multi-connected air conditioning system. The fixed minimum opening degree is not always appropriate or better under different air conditioning systems, different operating environments, and different operating states, and it is impossible to obtain better energy saving and safety. Therefore, the present application creatively proposes a technical solution for the control of the expansion valve opening degree of the multi-connected air conditioning system, which adaptively adjusts the minimum opening degree of the expansion valve corresponding to each indoor unit, obtains a minimum opening degree with strong viscosity and high matching degree according to the actual structure of the multi-connected air conditioning system, the current operating environment, and the current operating state, and the indoor unit operates at the adjusted minimum opening degree, which can effectively avoid problems such as system liquid return, high energy consumption, and system failure caused by inappropriate minimum opening degree, and improve the energy saving and safety of system operation.

[0060] Figure 1 Fig. 1 is a flow chart of a first embodiment of the control method for the expansion valve opening degree of the multi-connected air conditioning system according to the present application. Specifically, it is a flow chart of an embodiment of the minimum opening degree control of the expansion valve of a single indoor unit. In this embodiment, the multi-connected air conditioning system includes multiple indoor units, and each indoor unit corresponds to an expansion valve.

[0061] As shown in Fig. 2, this embodiment adopts the following process to control the expansion valve opening degree. Figure 1

[0062] Step 11: When a single indoor unit is in cooling operation and the minimum opening degree operating condition is met, the minimum opening degree of the operating indoor unit is obtained.

[0063] The minimum opening degree of the expansion valve corresponding to each indoor unit is stored in the air conditioning system. When the minimum opening degree operating condition in the cooling mode is met, the stored minimum opening degree of the indoor unit is called.

[0064] The minimum opening degree operating condition in the cooling mode can be a condition known in the prior art, which is not limited in this embodiment.​

[0065] Step 12: judging whether the minimum opening degree is an adjusted minimum opening degree. If yes, executing step 14; otherwise, executing step 13.

[0066] When the air conditioning system stores the minimum opening degree, a preset identifier can be set to represent whether the minimum opening degree is an adjusted minimum opening degree. During the operation of the air conditioning system, the identifier can be acquired to judge whether the current minimum opening degree is an adjusted minimum opening degree. Then, different controls are executed according to the judgment result.

[0067] Step 13: acquiring an initial minimum opening degree of the running indoor unit, and adjusting the initial minimum opening degree to obtain an adjusted minimum opening degree when the current superheat degree of the air conditioning system is less than a target superheat degree.

[0068] If the current minimum opening degree is not an adjusted minimum opening degree, that is, there is no adjusted minimum opening degree for the current running indoor unit, the process of minimum opening degree adjustment needs to be executed.

[0069] Specifically, an initial minimum opening degree of the running indoor unit is acquired, and then the initial minimum opening degree is adjusted to obtain an adjusted minimum opening degree when the current superheat degree of the air conditioning system is less than a target superheat degree. The initial minimum opening degree is generally a minimum opening degree preset when the air conditioning system is manufactured, or a minimum opening degree specified for the air conditioning system. For an expansion valve, the initial minimum opening degree is a fixed value. The current superheat degree is a superheat degree acquired in real time according to a certain sampling frequency, and the target superheat degree is a known value.

[0070] In this embodiment, if there is no adjusted minimum opening degree for the running indoor unit, the process of minimum opening degree adjustment will be executed according to the initial minimum opening degree, so as to obtain a minimum opening degree with strong viscosity and high matching degree to the actual structure of the multi-split air conditioning system, the current running environment and the current running state, etc. The adjustment is performed when the current superheat degree meets the condition of being less than the target superheat degree, which indicates that the minimum opening degree needs to be adjusted, thereby avoiding unnecessary additional operation processing consumption caused by the opening degree adjustment when the minimum opening degree does not need to be adjusted, and even avoiding the instability of the air conditioning system.

[0071] The specific implementation process of adjusting the initial minimum opening degree to obtain the adjusted minimum opening degree is described in subsequent embodiments.

[0072] Step 14: controlling the expansion valve of the running indoor unit based on the adjusted minimum opening degree.

[0073] If the running indoor unit has an adjusted minimum opening degree, or the adjusted minimum opening degree is obtained after the adjustment in step 13, the expansion valve will be controlled based on the adjusted minimum opening degree.

[0074] Since the adjusted minimum opening degree is adapted to the actual situation of each indoor unit, it is more consistent with the operation environment and state of the indoor unit, and is matched with the structure of the air conditioning system, thereby avoiding the problem of excessive or insufficient minimum opening degree of the indoor unit caused by using a fixed minimum opening degree for all indoor units, and improving the energy saving, safety and stability of the multi-split air conditioning system as a whole. Moreover, the adjustment of the initial minimum opening degree is not performed under all conditions, but is performed when the current superheat is less than the target superheat, thereby improving the rationality of the timing of the adjustment of the minimum opening degree and the effectiveness of the adjustment, and avoiding unstable operation of the air conditioning system caused by excessive adjustment.

[0075] Figure 2 Fig. 2 shows a flowchart of a second embodiment of the method for controlling the opening degree of the expansion valve of the multi-split air conditioning system according to the present application, and in particular, a flowchart of an embodiment of obtaining the adjusted minimum opening degree from the initial minimum opening degree.

[0076] As shown in Fig. 2, the embodiment obtains the adjusted minimum opening degree by the following process. Figure 2

[0077] Step 21: decrease the initial minimum opening degree at a set rate to obtain a preliminary adjusted minimum opening degree.

[0078] Step 22: control the expansion valve of the operating indoor unit according to the preliminary adjusted minimum opening degree until the current superheat is not less than the target superheat.

[0079] In this embodiment, the initial minimum opening degree is gradually decreased to adjust the opening degree. The set rate is a known value, and the initial minimum opening degree is decreased at the set rate to obtain a preliminary adjusted minimum opening degree each time, and then the expansion valve is controlled according to the preliminary adjusted minimum opening degree. In the process of controlling the expansion valve at the preliminary adjusted minimum opening degree, the current superheat is also obtained in real time and compared with the target superheat, and the decrease of the initial minimum opening degree is stopped when the current superheat is not less than the target superheat.

[0080] Step 23: determine the preliminary adjusted minimum opening degree when the current superheat is not less than the target superheat as the adjusted minimum opening degree.

[0081] In some embodiments, the set rate is 1 pls / 3 min. If the initial minimum opening degree is 52 pls, the initial minimum opening degree is decreased at a rate of 1 pls every 3 min to obtain a first preliminary adjusted minimum opening degree of 51 pls, and the expansion valve is controlled at 51 pls. If the current superheat is still greater than the target superheat within 3 min, the initial minimum opening degree is decreased again to obtain a second preliminary adjusted minimum opening degree of 50 pls. If the current superheat is not less than the target superheat within 3 min when the expansion valve is controlled at 50 pls, no further adjustment is performed, and the adjusted minimum opening degree is determined to be 50 pls.​

[0082] The method of the embodiment determines the adjusted minimum opening degree, has fast adjustment speed, and is simple and easy to implement. Figure 2 The method of the embodiment determines the adjusted minimum opening degree, has fast adjustment speed, and is simple and easy to implement.

[0083] Figure 3 The method of the embodiment determines the adjusted minimum opening degree, has fast adjustment speed, and is simple and easy to implement.

[0084] As shown in FIG. 4, the embodiment obtains the adjusted minimum opening degree by the following process. Figure 3 As shown in FIG. 4, the embodiment obtains the adjusted minimum opening degree by the following process.

[0085] Step 31: decrease the initial minimum opening degree according to the set rate to obtain a preliminary adjusted minimum opening degree.

[0086] Step 32: control the expansion valve of the indoor unit according to the preliminary adjusted minimum opening degree until the current superheat degree is not less than the target superheat degree, and record the preliminary adjusted minimum opening degree at the time when the current superheat degree is not less than the target superheat degree.

[0087] The set rate is a known value. After the initial minimum opening degree is decreased by the set rate each time, a preliminary adjusted minimum opening degree is obtained. Then, the expansion valve is controlled according to the preliminary adjusted minimum opening degree. In the process of controlling the expansion valve at the preliminary adjusted minimum opening degree, the current superheat degree is also obtained in real time and compared with the target superheat degree until the current superheat degree is not less than the target superheat degree. Then, the preliminary adjusted minimum opening degree at the time when the current superheat degree is not less than the target superheat degree is recorded.

[0088] Step 33: determine whether the set number is reached. If yes, execute step 35; otherwise, execute step 34.

[0089] Specifically, it is determined whether the number of the recorded preliminary adjusted minimum opening degrees at the time when the current superheat degree is not less than the target superheat degree reaches the set number, and then different control processes are executed according to the determination result. The set number is a preset value, for example, the set number is 3.

[0090] Step 34: increase the current preliminary adjusted minimum opening degree as a new initial minimum opening degree. Then, go to step 31.

[0091] If the set number does not reach the set number, the initial minimum opening degree will be updated. Specifically, the current preliminary adjusted minimum opening degree is increased as a new initial minimum opening degree. Then, go to step 31, and continue to execute the processes of steps 31, 32 and 33 until the number of the recorded preliminary adjusted minimum opening degrees reaches the set number, and then execute step 35.

[0092] In this embodiment, the reliability and accuracy of the initial minimum opening degree adjustment can be increased by adjusting the minimum opening degree multiple times in the manner of first reducing the initial minimum opening degree, then increasing the initial minimum opening degree and then establishing the minimum opening degree adjustment process again.

[0093] The current initial adjustment minimum opening degree refers to the initial adjustment minimum opening degree when the current superheat degree is not less than the target superheat degree and the number of recorded initial adjustment minimum opening degrees does not reach the set number. That is, it is the last recorded initial adjustment minimum opening degree.

[0094] The current initial adjustment minimum opening degree can be increased by a preset opening degree value. In other embodiments, the current initial adjustment minimum opening degree is increased by the preset opening degree value after a set interval, thereby improving the stability of system operation.

[0095] Step 35: determining the adjusted minimum opening degree according to all recorded initial adjustment minimum opening degrees.

[0096] All initial adjustment minimum opening degrees recorded in the set number are processed according to the set rule to obtain a minimum opening degree value, which is determined as the adjusted minimum opening degree. The processing of all initial adjustment minimum opening degrees recorded in the set number according to the set rule can be taking the average value, weighted average value, etc. of all initial adjustment minimum opening degrees, and the purpose is to obtain an adjusted minimum opening degree closer to the actual state and improve the accuracy of the adjusted minimum opening degree.

[0097] In some embodiments, the set rate of reducing the initial minimum opening degree is 1 pls / 3 min, the set number is 3, and the preset opening degree value of increasing the initial adjustment minimum opening degree is 5 pls. If the initial minimum opening degree is 52 pls, the initial minimum opening degree is reduced at a rate of 1 pls every 3 min, and the first initial adjustment minimum opening degree obtained is 51 pls. The expansion valve is controlled to operate at 51 pls, and if the current superheat degree is still greater than the target superheat degree within 3 min, the initial minimum opening degree is reduced again after 3 min, and the second initial adjustment minimum opening degree obtained is 50 pls. If the current superheat degree is not less than the target superheat degree within 3 min when the expansion valve is controlled to operate at 50 pls, 50 pls is recorded as the first initial adjustment minimum opening degree. At this time, 50 pls is the current initial adjustment minimum opening degree. Then, the expansion valve is controlled to continue operating at the current initial adjustment minimum opening degree of 50 pls for 3 min, and then it is increased by 5 pls to become 55 pls as the new initial minimum opening degree. Then, the initial minimum opening degree is 55 pls, and the opening degree adjustment is performed again in the manner of reducing at the set rate. The second and third initial adjustment minimum opening degrees recorded are 51 pls and 49 pls, respectively. Finally, the average value of the three recorded initial adjustment minimum opening degrees 50 pls, 51 pls and 49 pls is 50 pls, which is taken as the final adjusted minimum opening degree.

[0098] Figure 4 Fig. 4 is a flow chart of a fourth embodiment of the method for controlling the opening degree of the expansion valve of the multi-split air conditioning system according to the present application, and specifically, a flow chart of an embodiment of the minimum opening degree control of a single indoor unit. In this embodiment, the multi-split air conditioning system comprises a plurality of indoor units, and each indoor unit corresponds to an expansion valve.

[0099] As shown in Fig. 4, the embodiment controls the opening degree of the expansion valve by using the following process. Figure 4

[0100] Step 41: When the single indoor unit is in cooling operation and the minimum opening degree operation condition is met, the minimum opening degree of the operating indoor unit is obtained.

[0101] Step 42: Determine whether it is the adjusted minimum opening degree. If yes, execute Step 43; otherwise, go to Step 44.

[0102] The specific processing procedures of the above two steps are described in the description of the corresponding steps of the embodiments. Figure 1

[0103] Step 43: Determine whether the preset readjustment condition is met. If yes, execute Step 44; otherwise, go to Step 47.

[0104] If there is an adjusted minimum opening degree of the operating indoor unit, further determine whether the current state of the air conditioning system meets the preset readjustment condition, and execute different processes according to the determination result.

[0105] The readjustment condition is a preset known condition, and the setting principle of the readjustment condition is that if the state of the air conditioning system meets the readjustment condition, it indicates that the current minimum opening degree is an inappropriate minimum opening degree. In some embodiments, the readjustment condition includes any one of the conditions that the suction temperature of the compressor is less than a set suction temperature threshold, the indoor liquid pipe temperature is less than a set liquid pipe temperature threshold, and the difference between the indoor liquid pipe temperature and the indoor ambient temperature is less than a set temperature difference value.

[0106] Step 44: Obtain the initial minimum opening degree of the operating indoor unit and the current superheat degree of the air conditioning system.

[0107] When there is no adjusted minimum opening degree of the current operating indoor unit, or although there is an adjusted minimum opening degree but the state of the air conditioning system meets the preset readjustment condition, the process of adjusting the minimum opening degree will be executed, and the opening degree is adjusted according to the initial minimum opening degree. First, the initial minimum opening degree of the operating indoor unit and the current superheat degree of the air conditioning system are obtained.

[0108] Step 45: Determine whether the current superheat degree is less than the target superheat degree. If yes, execute Step 46; otherwise, go to Step 48.

[0109] ​​The target superheat is a preset value.

[0110] Step 46: Adjust the initial minimum opening to obtain the adjusted minimum opening. Then, proceed to step 47.

[0111] If the current superheat is less than the target superheat in step 45, it indicates that the minimum opening needs to be adjusted. The initial minimum opening will be adjusted to obtain the adjusted minimum opening. Figure 2 or Figure 3 Description of embodiments.

[0112] Step 47: Control the expansion valve of the indoor unit based on the adjusted minimum opening.

[0113] When it is determined in step 43 that the operating indoor unit already has an adjusted minimum opening and the air-conditioning system state does not meet the preset readjustment condition, or after the adjusted minimum opening is regained in step 46, the expansion valve of the operating indoor unit will be controlled according to the adjusted minimum opening.

[0114] Step 48: Control the operation of the expansion valve of the indoor unit based on the initial minimum opening.

[0115] If it is determined in step 45 that the current superheat is not less than the target superheat, indicating that the initial minimum opening is a more appropriate opening, the opening is temporarily not adjusted and the expansion valve is directly controlled according to the initial minimum opening.

[0116] Figure 5 This figure shows a schematic block diagram of the structure of a first embodiment of a device for controlling the opening of an expansion valve in a multi-split air conditioning system according to the present invention. Specifically, it illustrates a schematic block diagram of an embodiment of a device for controlling the minimum opening of an expansion valve in a single indoor unit. In this embodiment, the multi-split air conditioning system includes multiple indoor units, each of which corresponds to an expansion valve.

[0117] like Figure 5 As shown, the control device of this embodiment includes structural units, functions of the structural units, and relationships between them, as follows:

[0118] The control device includes:

[0119] The adjusted minimum opening determination unit 51 is configured to determine whether the operating indoor unit has an adjusted minimum opening when a single indoor unit is in cooling operation and meets the minimum opening operation condition.

[0120] The minimum opening adjustment unit 52 is used to obtain the initial minimum opening of the running indoor unit when the judgment result of the adjusted minimum opening judgment unit 51 is that the running indoor unit does not have an adjusted minimum opening, and to adjust the initial minimum opening to obtain the adjusted minimum opening when the current superheat of the air-conditioning system is less than the target superheat.

[0121] The expansion valve control unit 53 is configured to control the expansion valve of the operating indoor unit based on the adjusted minimum opening degree determined by the adjusted minimum opening degree determination unit 51 or the adjusted minimum opening degree obtained by the minimum opening degree adjustment unit 52.

[0122] The control device with the above structure runs the corresponding software program to perform the corresponding functions, and controls the multi-split air conditioning system according to the process of the control method of the expansion valve opening degree in the first embodiment and other embodiments to achieve the corresponding technical effects of the control method of the expansion valve opening degree in the first embodiment and other embodiments. Figure 1 The control device with the above structure runs the corresponding software program to perform the corresponding functions, and controls the multi-split air conditioning system according to the process of the control method of the expansion valve opening degree in the first embodiment and other embodiments to achieve the corresponding technical effects of the control method of the expansion valve opening degree in the first embodiment and other embodiments. Figure 1 The control device with the above structure runs the corresponding software program to perform the corresponding functions, and controls the multi-split air conditioning system according to the process of the control method of the expansion valve opening degree in the first embodiment and other embodiments to achieve the corresponding technical effects of the control method of the expansion valve opening degree in the first embodiment and other embodiments.

[0123] In some other embodiments, the control device can further include a re-adjustment condition determination unit configured to determine whether the current state of the air conditioning system satisfies a preset re-adjustment condition when the operating indoor unit has the adjusted minimum opening degree.

[0124] The minimum opening degree adjustment unit in the control device is further configured to re-adjust the initial minimum opening degree to obtain a re-adjusted minimum opening degree when the current state satisfies the preset re-adjustment condition and the current superheat degree of the air conditioning system is less than the target superheat degree. The expansion valve control unit is further configured to control the expansion valve of the operating indoor unit based on the re-adjusted minimum opening degree.

[0125] Figure 6 A structure schematic block diagram of a second embodiment of the control device of the expansion valve opening degree of the multi-split air conditioning system is shown. Specifically, it is a structure schematic block diagram of an embodiment of the minimum opening degree adjustment unit.

[0126] As shown in the structure schematic block diagram, the control device of this embodiment includes the following structure units, the functions of the structure units, and the relationships between the structure units, which are as follows: Figure 6

[0127] The minimum opening degree adjustment unit includes:

[0128] The initial minimum opening degree obtaining sub-unit 61 is configured to decrease the initial minimum opening degree at a set rate to obtain an initial adjusted minimum opening degree.

[0129] The adjusted minimum opening degree determination sub-unit 62 is configured to determine the initial adjusted minimum opening degree obtained by the initial minimum opening degree obtaining sub-unit 61 when the current superheat degree is not less than the target superheat degree as the adjusted minimum opening degree.

[0130] The expansion valve control unit 63 is configured to control the expansion valve of the operating indoor unit based on the adjusted minimum opening degree determined by the adjusted minimum opening degree determination sub-unit 62 and the initial minimum opening degree obtained by the initial minimum opening degree obtaining sub-unit 61.

[0131] ​The control device of the above structure runs the corresponding software program, executes the corresponding function, and controls the operation of the indoor unit according to the Figure 2 The control method of the above structure controls the operation of the multi-connected air conditioning system, achieves the corresponding technical effects of the Figure 2 embodiments and other embodiments.

[0132] Figure 7 A structure schematic block diagram of a third embodiment of the control device of the expansion valve opening degree of the multi-connected air conditioning system of the present application is shown. Specifically, it is a structure schematic block diagram of another embodiment of the minimum opening degree adjusting unit.

[0133] As shown in the figure, the control device of this embodiment includes the following structure units, the functions of the structure units, and the relationships between them, which are as follows: Figure 7

[0134] The minimum opening degree adjusting unit includes:

[0135] The initial minimum opening degree obtaining sub-unit 71 is configured to decrease the initial minimum opening degree at a set rate to obtain an initial minimum opening degree.

[0136] The initial minimum opening degree recording sub-unit 72 is configured to record the initial minimum opening degree when the current superheat degree is not less than the target superheat degree during the process of controlling the expansion valve of the indoor unit according to the initial minimum opening degree obtained by the initial minimum opening degree obtaining sub-unit 71.

[0137] The initial minimum opening degree quantity determining sub-unit 73 is configured to determine whether the quantity of the initial minimum opening degrees recorded by the initial minimum opening degree recording sub-unit 72 reaches a set quantity.

[0138] The initial minimum opening degree updating sub-unit 74 is configured to increase the current initial minimum opening degree as a new initial minimum opening degree when the initial minimum opening degree quantity determining sub-unit 73 determines that the quantity of the recorded initial minimum opening degrees does not reach the set quantity. Then, the opening degree adjustment is performed again based on the new initial minimum opening degree.

[0139] The adjusted minimum opening degree determining sub-unit 75 is configured to determine the adjusted minimum opening degree according to all the initial minimum opening degrees recorded by the initial minimum opening degree recording sub-unit 72 when the initial minimum opening degree quantity determining sub-unit 73 determines that the quantity of the recorded initial minimum opening degrees reaches the set quantity.

[0140] The control device of the above structure runs the corresponding software program, executes the corresponding function, and controls the operation of the indoor unit according to the Figure 3 The control method of the above structure controls the operation of the multi-connected air conditioning system, achieves the corresponding technical effects of the Figure 3 embodiments and other embodiments.

[0141] ​The control device of the expansion valve opening degree of the multi-connected air conditioning system of each of the above embodiments is applied to a multi-connected air conditioning system including multiple indoor units, and can improve the energy saving and safety of the multi-connected air conditioning system when operating at a minimum opening degree.

[0142] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can still be modified by those of ordinary skill in the art, or some technical features thereof can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions claimed by the present application.

Claims

1. A method of controlling an opening degree of an expansion valve of a multi-split air conditioning system, characterized by, The method comprises: When a single indoor unit is in refrigeration operation and meets a minimum opening degree operation condition, it is determined whether the operating indoor unit has an adjusted minimum opening degree; If the operating indoor unit has the adjusted minimum opening degree, an expansion valve of the operating indoor unit is controlled based on the adjusted minimum opening degree; If the operating indoor unit does not have the adjusted minimum opening degree, an initial minimum opening degree of the operating indoor unit is obtained, the initial minimum opening degree is adjusted when a current superheat degree of an air conditioning system is less than a target superheat degree, an adjusted minimum opening degree is obtained, and the expansion valve of the operating indoor unit is controlled based on the adjusted minimum opening degree; When the current superheat degree of the air conditioning system is less than the target superheat degree, the initial minimum opening degree is adjusted to obtain the adjusted minimum opening degree, which comprises: Step a: the initial minimum opening degree is reduced at a set rate to obtain an initial adjusted minimum opening degree; Step b: the expansion valve of the operating indoor unit is controlled according to the initial adjusted minimum opening degree until the current superheat degree is not less than the target superheat degree, and the initial adjusted minimum opening degree when the current superheat degree is not less than the target superheat degree is recorded; Step c: when the number of the recorded initial adjusted minimum opening degrees does not reach a set number, the current initial adjusted minimum opening degree is increased as a new initial minimum opening degree; Then, the steps a, b and c are continuously executed until the number of the recorded initial adjusted minimum opening degrees reaches the set number; Step d: the adjusted minimum opening degree is determined according to all the recorded initial adjusted minimum opening degrees.

2. The control method of the opening degree of the expansion valve of a multi-split air conditioning system according to claim 1, characterized in that, The method further comprises: If the operating indoor unit does not have the adjusted minimum opening degree, the initial minimum opening degree of the operating indoor unit is obtained, and the expansion valve of the operating indoor unit is controlled based on the initial minimum opening degree when a current superheat degree of an air conditioning system is not less than a target superheat degree.

3. The control method of the opening degree of the expansion valve of a packaged air conditioning system according to claim 1 or 2, characterized by, The method further comprises: If the operating indoor unit has the adjusted minimum opening degree, it is determined whether a current state of the air conditioning system meets a preset readjustment condition; If the preset readjustment condition is met, the initial minimum opening degree is adjusted again to obtain a readjusted minimum opening degree when a current superheat degree of an air conditioning system is less than a target superheat degree, and an expansion valve of the operating indoor unit is controlled based on the readjusted minimum opening degree; If the preset readjustment condition is not met, the expansion valve of the operating indoor unit is controlled based on the adjusted minimum opening degree.

4. A control device for opening degree of an expansion valve of a multi-split air conditioning system, characterized by, The device comprises: An adjusted minimum opening degree determination unit configured to determine whether a single operating indoor unit has an adjusted minimum opening degree when the single indoor unit is in refrigeration operation and meets a minimum opening degree operation condition; A minimum opening degree adjustment unit configured to obtain an initial minimum opening degree of the operating indoor unit when the operating indoor unit does not have the adjusted minimum opening degree, adjust the initial minimum opening degree when a current superheat degree of an air conditioning system is less than a target superheat degree, and obtain the adjusted minimum opening degree; An expansion valve control unit configured to control an expansion valve of the operating indoor unit based on the adjusted minimum opening degree; The minimum opening degree adjustment unit comprises: The initial minimum opening degree acquisition subunit is configured to decrease the initial minimum opening degree at a set rate to obtain an initial minimum opening degree; The initial minimum opening degree recording subunit is configured to record the initial minimum opening degree when the current superheat degree is not less than the target superheat degree during control of the expansion valve of the operating indoor unit according to the initial minimum opening degree by the expansion valve control unit; The initial minimum opening degree number determination subunit is configured to determine whether the number of the recorded initial minimum opening degrees reaches a set number; The initial minimum opening degree updating subunit is configured to increase the current initial minimum opening degree as a new initial minimum opening degree when the number of the recorded initial minimum opening degrees does not reach the set number; The adjusted minimum opening degree determination subunit is configured to determine the adjusted minimum opening degree according to all the recorded initial minimum opening degrees after the number of the recorded initial minimum opening degrees reaches the set number.

5. The control device of the opening degree of the expansion valve of a multi-split air conditioning system according to claim 4, characterized in that, The device further comprises: The readjustment condition judgment subunit is configured to judge whether a current state of the air conditioning system meets a preset readjustment condition when the operating indoor unit has the adjusted minimum opening degree; The minimum opening degree adjustment subunit is further configured to re-adjust to obtain a readjusted minimum opening degree according to the initial minimum opening degree when the current state meets the preset readjustment condition and the current superheat degree of the air conditioning system is less than the target superheat degree; The expansion valve control unit is further configured to control the expansion valve of the operating indoor unit based on the readjusted minimum opening degree.

6. A multi-split air conditioning system comprising a plurality of indoor units, each of the indoor units corresponding to an expansion valve, characterized in that, The multi-split air conditioning system further comprises the control device of the opening degree of the expansion valve according to the above claim 4 or 5.

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