Central air conditioning control method and device, central air conditioner and storage medium

Abstract

The present disclosure provides a control method and device of a central air conditioner, the central air conditioner and a storage medium, wherein the method comprises: judging whether an indoor unit is a first missing indoor unit according to an operation mode of the central air conditioner, a communication state between the indoor unit and an outdoor unit and opening degree information of a throttling device of the indoor unit, and counting a first number of all the first missing indoor units; and performing control processing on the central air conditioner based on the operation mode of the central air conditioner, the first number and operation parameters of the central air conditioner. The present disclosure can make other indoor units work normally in the case of partial indoor unit loss, does not affect the overall operation of the central air conditioner, can ensure the operation safety of the central air conditioner and improve the reliability of the central air conditioner; can meet the use demand of users and improve the use experience of users.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a control method, device, central air conditioning unit, and storage medium for a central air conditioning system. Background Technology

[0002] Central air conditioning refers to a unit consisting of one outdoor unit connected to at least two indoor units via piping. Central air conditioning systems can include various multi-split systems. During operation, power outages sometimes occur in the indoor units. After a power outage, the electronic expansion valve of the indoor unit will remain at its pre-outage opening. If the central air conditioning system continues to operate, refrigerant may flow through the de-energized indoor units. This uncontrolled bypass of refrigerant can affect the safe operation of the central air conditioning system, potentially causing compressor damage. Current control methods typically shut down the central air conditioning system if the number of indoor units experiencing power outages is greater than or equal to a set number. However, in some cases, the electronic expansion valve of a de-energized indoor unit may be at zero or low opening, not significantly impacting the operational safety of the central air conditioning system, allowing it to continue operating normally. Using existing control methods, shutting down the central air conditioning system when it can operate normally may affect the operation of other indoor units, preventing normally functioning units from working and thus failing to meet user needs. Summary of the Invention

[0003] In view of this, one technical problem to be solved by the present invention is to provide a control method, device, central air conditioner and storage medium for a central air conditioner, which can control the central air conditioner according to the operating mode of the central air conditioner, the communication status between the indoor unit and the outdoor unit and the opening degree of the throttling device of the indoor unit, and in combination with the operating status of the central air conditioner.

[0004] According to a first aspect of this disclosure, a control method for a central air conditioning system is provided. The central air conditioning system includes an outdoor unit and an indoor unit. The method includes: determining whether an indoor unit is a first missing indoor unit based on the operating mode of the central air conditioning system, the communication status between the indoor unit and the outdoor unit, and the opening information of the throttling device of the indoor unit, and counting a first number of all first missing indoor units; and performing control processing on the central air conditioning system based on the operating mode of the central air conditioning system, the first number, and the operating parameters of the central air conditioning system.

[0005] Optionally, determining whether the indoor unit is the first missing indoor unit based on the operating mode of the central air conditioner, the communication status between the indoor unit and the outdoor unit, and the opening information of the throttling device of the indoor unit includes: in the case that the communication between the indoor unit and the outdoor unit is interrupted, obtaining the opening information of the throttling device before the communication interruption; and determining whether the indoor unit is the first missing indoor unit based on the operating mode of the central air conditioner and the opening information.

[0006] Optionally, determining whether the indoor unit is the first missing indoor unit based on the operating mode of the central air conditioner and the opening information includes: determining the indoor unit as the first missing indoor unit when the operating mode of the central air conditioner is cooling mode and the opening information is not 0.

[0007] Optionally, determining whether the indoor unit is the first missing indoor unit based on the operating mode of the central air conditioner and the opening information includes all of the following options: if the operating mode of the central air conditioner is heating mode and the opening information is greater than the opening threshold, the indoor unit is determined to be the first missing indoor unit.

[0008] Optionally, the operating parameters include: the compressor discharge temperature and compressor suction pressure of the outdoor unit, and the average superheat of the indoor unit operating in cooling mode; the control processing of the central air conditioning system based on the operating mode of the central air conditioning system, the first quantity, and the operating parameters of the central air conditioning system includes: when the operating mode of the central air conditioning system is cooling mode and the cooling alarm shutdown conditions are met, performing alarm processing and controlling the central air conditioning system to shut down; wherein, the cooling alarm shutdown conditions include all of the following options: the first quantity is greater than or equal to the indoor unit missing quantity threshold, the compressor discharge temperature is less than the discharge low temperature threshold, the compressor suction pressure is less than the system low pressure threshold, and the average superheat is greater than the target superheat and the duration is greater than or equal to the first duration threshold.

[0009] Optionally, if the central air conditioning is in cooling mode and the cooling alarm shutdown conditions are not met, the central air conditioning can be controlled to operate.

[0010] Optionally, the operating parameters include: the compressor exhaust temperature, compressor suction pressure, and compressor exhaust pressure of the outdoor unit; the control processing of the central air conditioner based on the operating mode of the central air conditioner, the first quantity, and the operating parameters of the central air conditioner includes: when the operating mode of the central air conditioner is heating mode and the heating alarm shutdown conditions are met, performing alarm processing and controlling the central air conditioner to shut down; wherein, the heating alarm shutdown conditions include: the first quantity is greater than or equal to the indoor unit missing quantity threshold, the compressor exhaust temperature is greater than the exhaust high temperature threshold, the compressor suction pressure is less than the system low pressure threshold, the compressor exhaust pressure is less than or equal to the exhaust pressure threshold, and the duration of the duration is greater than or equal to a second duration threshold.

[0011] Optionally, if the central air conditioning is in heating mode and the heating alarm shutdown conditions are not met, the central air conditioning can be controlled to operate.

[0012] Optionally, after controlling the central air conditioning to stop and receiving a unit start command, based on the communication status between the indoor unit and the outdoor unit, it is determined whether the indoor unit is a second missing indoor unit, and the second number of all second missing indoor units and the first number are counted; based on the operating mode of the central air conditioning and the second number, or based on the operating mode of the central air conditioning and the second number and the first number, it is determined whether to control the central air conditioning to restart.

[0013] Optionally, determining whether to control the central air conditioning to restart includes: if the central air conditioning is in cooling mode and the cooling start condition is met, determining to control the central air conditioning to restart; wherein the cooling start condition includes: the second quantity is less than the threshold of the number of missing indoor units.

[0014] Optionally, determining whether to control the central air conditioning to restart includes: if the central air conditioning is in heating mode and the heating start-up conditions are met, determining to control the central air conditioning to restart; wherein, the heating restart-up conditions include: the difference between the second quantity and the first quantity is less than the threshold for the number of missing indoor units.

[0015] Optionally, determining whether the indoor unit is the second missing indoor unit based on the communication status between the indoor unit and the outdoor unit includes: determining that the indoor unit is the second missing indoor unit if it is determined that the communication between the indoor unit and the outdoor unit is interrupted.

[0016] Optionally, after the central air conditioning is restarted, it is determined whether to control the central air conditioning to operate at full capacity based on the operating mode of the central air conditioning, the second quantity, the operating time of the compressor, or based on the operating mode of the central air conditioning, the second quantity and the first quantity, and the operating time of the compressor.

[0017] Optionally, determining whether to control the central air conditioning to operate at full capacity includes: if the central air conditioning is in cooling mode, and the duration of the first indoor unit's absence is greater than or equal to a first absence duration threshold, and the operating time of the compressor is greater than or equal to a first operating time threshold, then determining to control the central air conditioning to operate at full capacity; wherein, the duration of the first indoor unit's absence is the duration between the current time and the time when the first indoor unit's absence is confirmed; and the time when the first indoor unit's absence is confirmed is the moment when the second quantity is first confirmed to be greater than or equal to the threshold for the number of indoor units missing.

[0018] Optionally, determining whether to control the central air conditioning to operate at full capacity includes: if the central air conditioning is in heating mode, and the duration of the second indoor unit's absence is greater than or equal to a second absence duration threshold, and the operating time of the compressor is greater than or equal to a second operating time threshold, then determining to control the central air conditioning to operate at full capacity; wherein, the duration of the second indoor unit's absence is the duration between the current time and the time when the second indoor unit's absence is confirmed; and the time when the second indoor unit's absence is confirmed is the moment when it is first confirmed that the difference between the second quantity and the first quantity is greater than or equal to the threshold for the number of indoor units missing.

[0019] According to a second aspect of this disclosure, a control device for a central air conditioning system is provided. The central air conditioning system includes an outdoor unit and an indoor unit. The control device includes: an indoor unit missing determination module, configured to determine whether an indoor unit is a first missing indoor unit based on the operating mode of the central air conditioning system, the communication status between the indoor unit and the outdoor unit, and the opening information of the throttling device of the indoor unit, and to count a first number of all first missing indoor units; and a control execution module, configured to perform control processing on the central air conditioning system based on the operating mode of the central air conditioning system, the first number, and the operating parameters of the central air conditioning system.

[0020] According to a third aspect of this disclosure, a control device for a central air conditioning system is provided, comprising: a memory; and a processor coupled to the memory, the processor being configured to perform the method described above based on instructions stored in the memory.

[0021] According to a fourth aspect of this disclosure, a central air conditioning system is provided, including a control device for the central air conditioning system as described above.

[0022] According to a fifth aspect of this disclosure, a computer-readable storage medium is provided that stores computer instructions which, when executed by a processor, perform the method described above.

[0023] The central air conditioning control method, device, central air conditioning unit, and storage medium disclosed herein can count the number of missing indoor units based on the unit's operating mode, the communication status between the indoor and outdoor units, and the opening degree of the indoor unit's throttling device. Combined with the unit's operating status, it controls the operation or shutdown of the central air conditioning system. Even when some indoor units are missing, other indoor units can still operate normally without affecting the overall operation of the central air conditioning system. This ensures the operational safety and improves the reliability of the central air conditioning system; it also meets user needs and enhances the user experience. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic flowchart of one embodiment of the central air conditioning control method according to the present disclosure;

[0026] Figure 2 This is a schematic diagram of the distributed layout of a central air conditioning system.

[0027] Figure 3 This is a schematic diagram of a process for determining whether an indoor unit is missing in one embodiment of the central air conditioning control method according to the present disclosure;

[0028] Figure 4 This is a schematic flowchart illustrating the execution of control processing on a central air conditioning system according to one embodiment of the central air conditioning control method of the present disclosure.

[0029] Figure 5 This is a schematic diagram of the process of controlling the restart of a central air conditioning system according to one embodiment of the central air conditioning control method of the present disclosure;

[0030] Figure 6 A schematic diagram of a module of a central air conditioning control device according to an embodiment of the present disclosure;

[0031] Figure 7 A schematic diagram of a module of another embodiment of a central air conditioning control device according to the present disclosure;

[0032] Figure 8 This is a schematic diagram of a module of yet another embodiment of the control device for a central air conditioning system according to the present disclosure. Detailed Implementation

[0033] Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of the embodiments are described in the specification. However, it should be understood that many implementation-specific settings must be made in carrying out the embodiments to achieve the developer's specific goals, such as complying with constraints related to the device and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the present disclosure.

[0034] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this disclosure.

[0035] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of this disclosure are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0036] It should also be understood that in the embodiments disclosed herein, "a plurality of" may refer to two or more, and "at least one" may refer to one, two or more.

[0037] It should also be understood that any component, data or structure mentioned in the embodiments of this disclosure can generally be understood as one or more unless expressly defined or given to the contrary in the context.

[0038] Furthermore, the term "and / or" in this disclosure is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this disclosure generally indicates that the preceding and following related objects have an "or" relationship.

[0039] It should also be understood that the description of the various embodiments in this disclosure emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0040] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0041] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0042] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0044] Furthermore, to avoid obscuring this disclosure with unnecessary detail, only processing steps and / or apparatus structures closely related to at least the solutions according to this disclosure are shown in the accompanying drawings, while other details less relevant to this disclosure are omitted. It should also be noted that similar reference numerals and letters in the drawings indicate similar items, and therefore once an item is defined in one drawing, it need not be discussed again in subsequent drawings.

[0045] In the related technologies known to the inventor, power outages sometimes occur in indoor units during the operation of central air conditioning systems. Due to the distributed layout of central air conditioning systems, refrigerant control requires flow regulation between individual indoor units. After a power outage, the expansion valve of an indoor unit becomes uncontrollable, and the electronic expansion valve remains at its pre-power-out opening. If the central air conditioning system continues to operate, refrigerant may flow through the de-energized indoor units. This uncontrolled bypass of refrigerant can affect the operational safety of the central air conditioning system. If too many indoor units experience power outages, it may cause refrigerant leakage, prevent the compressor from returning oil in time, and damage the compressor.

[0046] Central air conditioning systems require a unified power supply for both indoor and outdoor units. However, in actual installation, it's difficult to guarantee this unified power supply. Unified power supply would increase installation costs and complexity. For example, if the outdoor units are installed on the roof or ground floor, and the indoor units are installed in individual rooms on floors 1-5, a unified power supply for both would require connecting all power sources across floors 1-5, designing a distribution cabinet, and increasing installation difficulty and labor costs.

[0047] In existing multi-split air conditioning control methods, if the number of indoor units experiencing power outages is less than a set number, the central air conditioning system continues to operate; if the number of indoor units experiencing power outages is greater than or equal to the set number, the central air conditioning system shuts down. However, after some indoor units lose power, the opening degree of their electronic expansion valves is 0 or very small, which does not significantly affect the operation of the central air conditioning system, allowing it to operate normally. Using existing central air conditioning control methods, it is possible to shut down a multi-split system when the central air conditioning system can operate normally, preventing normally functioning indoor units from working, causing inconvenience to users and failing to meet their needs.

[0048] Figure 1 This is a schematic flowchart of one embodiment of the central air conditioning control method according to the present disclosure, as shown below. Figure 1 As shown:

[0049] Step 101: Based on the central air conditioning operating mode, the communication status between the indoor unit and the outdoor unit, and the opening information of the throttling device of the indoor unit, determine whether the indoor unit is the first missing indoor unit, and count the first number of all first missing indoor units.

[0050] In one embodiment, a central air conditioning system includes various multi-split systems, modular units, etc.; various units that consist of one or more outdoor units as a whole, and where this outdoor unit module connects to multiple indoor units, all fall under the category of the central air conditioning system disclosed herein. Figure 2 As shown, the central air conditioning system includes an outdoor unit 21 and indoor units 22. There are multiple indoor units 22, which can be installed in various rooms. The central air conditioning system can operate in heating or cooling mode, and the communication status between the indoor and outdoor units can be interrupted or normal.

[0051] The throttling device in the indoor unit can be an electronic expansion valve, etc., and the opening information of the throttling device is the opening degree of the electronic expansion valve, etc. The electronic expansion valve is installed in the indoor unit to regulate refrigerant pressure and flow rate, ensuring reliable heat exchange. Each indoor unit and outdoor unit of the central air conditioning system is connected by pipes, and the refrigerant flow rate is controlled by adjusting the opening degree of the electronic expansion valve in the indoor unit.

[0052] Step 102: Based on the central air conditioning's operating mode, the first quantity, and the central air conditioning's operating parameters, perform control processing on the central air conditioning.

[0053] In one embodiment, the operating parameters of the central air conditioning system can be multiple parameters, such as compressor exhaust temperature and compressor suction pressure. Control processing of the central air conditioning system includes controlling the operation or shutdown of the multi-split unit.

[0054] The central air conditioning control method in the above embodiments counts the number of missing indoor units based on the unit's operating mode, the communication status between the indoor and outdoor units, and the opening degree of the indoor unit's throttling device. It then controls the operation or shutdown of the multi-split unit in conjunction with the unit's operating status. This allows other indoor units to operate normally even when some indoor units are missing, without affecting the overall operation of the central air conditioning system. This ensures the operational safety and improves the reliability of the central air conditioning system, meets user needs, and enhances the user experience.

[0055] Figure 3 This is a schematic diagram illustrating the process of determining whether an indoor unit is missing in one embodiment of the central air conditioning control method according to the present disclosure. Figure 3 As shown:

[0056] Step 301: If it is determined that the communication between the indoor unit and the outdoor unit is interrupted, obtain the opening information of the throttling device before the communication interruption.

[0057] In one embodiment, communication between the indoor and outdoor units is interrupted when the indoor unit loses power or malfunctions. The indoor and outdoor units can exchange data via a CAN bus. If the indoor unit loses power or the communication line is disconnected, the indoor unit cannot send data to the CAN bus, and the outdoor unit cannot receive data from the indoor unit. If it is determined that the outdoor unit has not received any data from the indoor unit within a preset time period (e.g., 5 minutes, 10 minutes, 20 minutes, etc.), then communication between the indoor and outdoor units is considered interrupted.

[0058] The outdoor unit can receive data sent by the indoor unit in real time, including information such as the current opening degree of the indoor unit's electronic expansion valve, and record this data. Based on the data received by the outdoor unit from the indoor unit before the communication interruption, the outdoor unit obtains the opening degree information of the electronic expansion valve throttling device and other throttling devices last reported by the indoor unit, which serves as the opening degree information of the electronic expansion valve throttling device and other throttling devices before the communication interruption; alternatively, it obtains the opening degree information of multiple electronic expansion valve throttling devices and other throttling devices reported by the indoor unit before the communication interruption, and uses various methods to determine the opening degree information of the electronic expansion valve throttling device and other throttling devices before the communication interruption based on these multiple opening degree information.

[0059] Step 302: Determine whether the indoor unit is the first missing indoor unit based on the central air conditioning's operating mode and opening information.

[0060] By obtaining the opening information of the throttling device of the indoor unit where communication is interrupted, and combining it with the operating mode of the central air conditioning system to determine the number of missing indoor units, the number of missing indoor units affecting the safe operation of the central air conditioning system can be accurately determined. Based on this number, the operation or shutdown of the multi-split system can be controlled. This allows other indoor units to work normally even when some indoor units are missing, ensuring the safe operation of the central air conditioning system and improving its reliability.

[0061] In one embodiment, the connecting pipes between the indoor and outdoor units of a central air conditioning system are interconnected, and the operation of the central air conditioning system requires control of refrigerant flow. If an indoor unit is missing, its electronic expansion valve cannot be controlled, and the original refrigerant may remain in the indoor unit, resulting in insufficient refrigerant in the entire central air conditioning system. This causes the compressor's suction pressure to be low, oil return to be delayed, and the compressor to operate in an oil-deficient state, leading to compressor malfunction.

[0062] When communication between the indoor and outdoor units is interrupted, if the central air conditioning is in cooling mode and the opening information is not 0, the indoor unit is identified as the first missing indoor unit.

[0063] For example, when the central air conditioning is operating in cooling mode, to count the first number B of all missing indoor units, the initial value of the first number B can be set to 0. When it is determined that the communication between an indoor unit and the outdoor unit is interrupted, the opening information of the indoor unit's motor expansion valve before the communication interruption is obtained based on the data received by the outdoor unit from the indoor unit before the communication interruption. If the opening information of the electronic expansion valve is non-zero, the indoor unit is determined to be the first missing indoor unit, and the first number B is incremented by 1; if the opening information of the electronic expansion valve is zero, it is not included in the first number B.

[0064] When a central air conditioning system is in cooling mode, the refrigerant circulates through the outdoor unit first and then the indoor unit. The outdoor unit has an overcooler for refrigerant bypass, allowing the refrigerant to bypass the indoor units that are not running. The electronic expansion valve of an indoor unit that is not running will have an opening of 0, thus not affecting system operation. If the electronic expansion valve of an indoor unit with communication interruption is closed (opening information is 0), this indoor unit will not significantly impact the overall operation of the central air conditioning system, which can continue to operate normally.

[0065] By obtaining the opening information of the throttling device in cooling mode, the number of missing indoor units that affect the operational safety of the central air conditioning system in cooling mode can be accurately determined. Based on this number, the operation or shutdown of the multi-split system can be controlled. This allows other indoor units to work normally in cooling mode, ensuring the operational safety of the central air conditioning system and improving its reliability.

[0066] In one embodiment, when communication between the indoor and outdoor units is interrupted, if the central air conditioning system is in heating mode and the opening degree information is greater than the opening degree threshold, the indoor unit is identified as the first missing indoor unit. The various thresholds disclosed herein can be configured according to different application scenarios, operating modes, etc.

[0067] For example, when the central air conditioning is in heating mode, to count the first number B of all missing indoor units, the initial value of the first number B can be set to 0. When it is determined that the communication between an indoor unit and the outdoor unit is interrupted, the opening information of the electronic expansion valve of the indoor unit before the communication interruption is obtained based on the data sent by the indoor unit to the outdoor unit before the communication interruption. If the opening information of the electronic expansion valve is greater than the opening threshold P (e.g., 280PLS), then the indoor unit is determined to be the first missing indoor unit, and the first number B is incremented by 1. If the opening information of the electronic expansion valve before the communication between the indoor unit and the outdoor unit is less than or equal to the opening threshold P, then it is not included in the first number B.

[0068] When a central air conditioning system is in heating mode, the refrigerant circulation first passes through the indoor unit. Therefore, the indoor unit, which is not currently running, needs to be opened to a certain degree to allow the refrigerant to bypass and circulate. Otherwise, the refrigerant flow in the central air conditioning system will encounter significant resistance.

[0069] In heating mode, if communication between the indoor and outdoor units is interrupted, the throttling device of the indoor unit cannot be controlled. When the opening degree of the throttling device of this indoor unit is greater than the opening threshold, it may lead to insufficient refrigerant in the central air conditioning system, affecting the safe operation of the central air conditioning system. In this case, the indoor unit is identified as the first missing indoor unit. When the opening degree of the throttling device of this indoor unit is less than or equal to the opening threshold, it usually does not affect the safe operation of the central air conditioning system, and this indoor unit is not identified as the first missing indoor unit. By obtaining the opening degree information of the throttling device in heating mode, the number of missing indoor units that affect the operational safety of the central air conditioning system in heating mode can be accurately determined. Based on this number, the operation or shutdown of the multi-split system can be controlled. This allows other indoor units to work normally in heating mode, ensuring the operational safety of the central air conditioning system and improving its reliability.

[0070] Figure 4 This is a schematic diagram illustrating the flow of control processing of a central air conditioning system according to one embodiment of the central air conditioning control method of this disclosure, as shown below. Figure 4 As shown:

[0071] Step 401: Control the central air conditioning cooling operation.

[0072] Step 403: Determine whether the cooling alarm shutdown conditions are met. If yes, proceed to step 405; otherwise, proceed to step 406.

[0073] Step 405: Initiate alarm processing and shut down the central air conditioning system.

[0074] Step 406: Control the central air conditioning to continue operating.

[0075] In one embodiment, the operating parameters of the central air conditioning system include: the compressor discharge temperature and compressor suction pressure of the outdoor unit, and the average superheat of the indoor unit performing cooling operation. Cooling alarm shutdown conditions include: a first quantity greater than or equal to a threshold for the number of missing indoor units, a compressor discharge temperature less than a low discharge temperature threshold, a compressor suction pressure less than a system low pressure threshold, and an average superheat greater than a target superheat for a duration greater than or equal to a first duration threshold.

[0076] Compressor discharge temperature refers to the temperature at which the refrigerant is converted into a high-temperature, high-pressure gas during the operation of the compressor in the outdoor unit. A temperature sensor can be added to the compressor discharge port to detect the compressor discharge temperature. Compressor suction pressure is the pressure at which the compressor draws air from the outdoor unit. A pressure sensor can be added to the compressor suction port to detect the compressor suction pressure.

[0077] The superheat of an indoor unit operating in cooling mode refers to the temperature difference between the outlet and inlet temperatures of an indoor unit that is in a non-disruptive state and operating in cooling mode; the average superheat of an indoor unit operating in cooling mode refers to the average superheat of all indoor units operating in cooling mode. A first duration threshold can be set, for example, to 30 minutes.

[0078] If the central air conditioning system is in cooling mode and the cooling alarm shutdown conditions are met, an alarm will be triggered and the central air conditioning system will be shut down. If the central air conditioning system is in cooling mode and the cooling alarm shutdown conditions are not met, the central air conditioning system will be kept running.

[0079] For example, if the central air conditioning system is operating in cooling mode, and the first quantity B is greater than or equal to the missing indoor unit threshold C (e.g., C is 3 units), and if the compressor discharge temperature is lower than the discharge low temperature threshold, and the compressor suction pressure is lower than the system low pressure threshold (in central air conditioning operation, excessively low discharge temperature and excessively low system low pressure indicate that the refrigerant circulation of this unit is not smooth or there is a refrigerant leak), and if the average superheat is greater than the target superheat and remains above the first duration threshold (the outlet temperature of the indoor unit is higher than the inlet temperature, the cooling effect of the indoor unit is poor, and it cannot meet the user's cooling requirements, indicating that the central air conditioning system has insufficient refrigerant and there may be a refrigerant leak flowing to the missing indoor unit), then the cooling alarm shutdown conditions are met, an alarm is triggered, and the central air conditioning system is shut down. Alarm processing can employ various audible and visual alarm methods, and shutting down the central air conditioning system can control the shutdown of both the outdoor and indoor units, preventing the central air conditioning system from starting.

[0080] By combining cooling modes and central air conditioning operating parameters to control the operation or shutdown of the central air conditioning system, it is possible to disconnect a missing indoor unit from the central air conditioning system without affecting the overall operational reliability of the central air conditioning system, allowing other indoor units to operate normally without affecting the overall cooling operation of the central air conditioning system. This ensures the operational safety of the central air conditioning system and improves its reliability; it can also meet user needs and enhance the user experience.

[0081] Step 402: Control the central air conditioning system to operate in heating mode.

[0082] Step 404: Determine whether the heating alarm shutdown conditions are met. If yes, proceed to step 405; otherwise, proceed to step 406.

[0083] In one embodiment, the operating parameters of the central air conditioning system include: compressor discharge temperature, compressor suction pressure, and compressor discharge pressure of the outdoor unit. Heating alarm shutdown conditions include: a first quantity greater than or equal to a threshold for the number of missing indoor units, compressor discharge temperature greater than a high-temperature discharge threshold, compressor suction pressure less than a system low-pressure threshold, and compressor discharge pressure less than or equal to a discharge pressure threshold for a duration greater than or equal to a second duration threshold (e.g., 30 minutes). A pressure sensor can be installed at the compressor discharge outlet to detect the discharge pressure at the compressor outlet, i.e., to detect the compressor discharge pressure.

[0084] If the central air conditioning system is in heating mode and the heating alarm shutdown conditions are met, an alarm will be triggered and the central air conditioning system will be shut down. If the central air conditioning system is in heating mode and the heating alarm shutdown conditions are not met, the central air conditioning system will be kept running.

[0085] For example, if the central air conditioning system is operating in heating mode, and the first quantity B is greater than or equal to the threshold C for the number of missing indoor units (e.g., C is 3 units), and if the compressor discharge temperature is greater than the high-temperature discharge threshold and the compressor suction pressure is less than the low-pressure system threshold (in central air conditioning operation, excessively high discharge temperature and excessively low system pressure indicate that the refrigerant circulation of this central air conditioning system is not smooth or there is a refrigerant leak), and if the system malfunctioning compressor discharge pressure is less than the discharge pressure threshold and remains below the second duration threshold T (the discharge pressure threshold PH can be 2260 kPa, etc., excessively low high pressure during heating operation indicates insufficient refrigerant in the central air conditioning system, and there may be excessive refrigerant leakage with refrigerant flowing to the missing indoor units), then it is determined that the heating alarm shutdown conditions are met, an alarm is triggered, and the central air conditioning system is shut down. The alarm can be triggered by various audible and visual alarms, and the central air conditioning system can be shut down by controlling both the outdoor and indoor units, preventing the central air conditioning system from starting.

[0086] By combining heating mode and central air conditioning operating parameters to control the operation or shutdown of the central air conditioning system, it is possible to disconnect a missing indoor unit from the central air conditioning system without affecting the overall operational reliability of the central air conditioning system, allowing other indoor units to operate normally without affecting the overall heating operation of the central air conditioning system. This ensures the operational safety of the central air conditioning system and improves its reliability; it can also meet user needs and enhance the user experience.

[0087] Figure 5 This is a schematic diagram of the process of restarting a central air conditioning unit according to one embodiment of the central air conditioning control method of this disclosure, as shown below. Figure 5 As shown:

[0088] Step 501: After controlling the central air conditioning to stop and receiving the unit start command, determine whether the indoor unit is the second missing indoor unit based on the communication status between the indoor unit and the outdoor unit, and count the second number of all second missing indoor units.

[0089] In one embodiment, the indoor unit can be identified as the second missing indoor unit if communication between the indoor and outdoor units is interrupted during the operation of the central air conditioning system or after the central air conditioning system is shut down and a unit start command is received.

[0090] If the outdoor unit does not receive any data from the indoor unit within a preset time period (e.g., 5 minutes, 10 minutes, 20 minutes, etc.), it is determined that the communication between the indoor and outdoor units is interrupted, and this indoor unit is identified as the second missing indoor unit. The second quantity A of all second missing indoor units and the first quantity B of all first missing indoor units are then counted. After determining the first quantity B, it is stored in a storage module. Before the central air conditioning system shuts down, if the value of the first quantity B changes, the first quantity B stored in the storage module is updated. After the central air conditioning system shuts down and a unit start command is received, the second quantity A of all second missing indoor units is counted. If the second quantity A is determined and the first quantity B needs to be counted, the first quantity B is retrieved from the storage module.

[0091] Step 502: Determine whether to control the central air conditioning to restart based on the central air conditioning's operating mode and the second quantity, or based on the central air conditioning's operating mode, the second quantity, and the first quantity.

[0092] By controlling the restart of the central air conditioning system based on the unit's operating mode and the number of missing indoor units, the operational safety of the central air conditioning system can be ensured, and the reliability of its startup can be improved.

[0093] In one embodiment, after the central air conditioning system is shut down, issues such as power outages or communication failures in the indoor units can be resolved manually. After the central air conditioning system is shut down, the first and second quantities can continue to be tallied.

[0094] If the central air conditioning is in cooling mode and the cooling start conditions are met, the central air conditioning will be restarted. The cooling start conditions include: the second quantity is less than the threshold for the number of missing indoor units, etc.

[0095] For example, after controlling the central air conditioning to stop and receiving a unit start command, the unit start command mode is cooling mode. When the central air conditioning is in cooling mode, if it is determined that the second quantity A is less than the indoor unit missing quantity threshold C (C can be 3, etc.), then it is determined to control the central air conditioning to restart, starting the compressor of the outdoor unit and the indoor unit indicated by the unit start command.

[0096] If the central air conditioning is in heating mode and the heating start-up conditions are met, the central air conditioning will be restarted. The conditions for restarting heating include: the difference between the second quantity and the first quantity is less than the threshold for the number of missing indoor units.

[0097] For example, before the communication between the indoor and outdoor units is interrupted, the opening information of the electronic expansion valve of the indoor unit is less than or equal to the opening threshold P. This part of the indoor unit contains refrigerant and corresponding compressor lubricating oil. After controlling the central air conditioning to stop and receiving the unit start command, the central air conditioning operates in heating mode, and the difference between the second quantity A and the first quantity B is calculated as D.

[0098] Communication between all D indoor units and the outdoor unit is interrupted, the throttling devices of the D indoor units cannot be controlled, and before the communication between the D indoor units and the outdoor unit is interrupted, the opening information of the electronic expansion valve of the D indoor units is less than or equal to the opening threshold. When D is greater than the threshold for the number of missing indoor units, since each of the D indoor units contains refrigerant and corresponding compressor lubricating oil, it may lead to insufficient refrigerant in the central air conditioning system, affecting the safe operation of the central air conditioning system. If it is determined that D is less than the threshold for the number of missing indoor units C (C can be 3, etc.), it usually does not affect the safe operation of the central air conditioning system. It is determined to restart the central air conditioning system and start the compressor of the outdoor unit and the indoor unit indicated by the unit start command.

[0099] By controlling the restart of the central air conditioning system based on the number of missing indoor units in either cooling or heating mode, the operational safety of the central air conditioning system can be ensured, and its reliability can be improved.

[0100] In one embodiment, after the central air conditioning system restarts, a decision is made regarding whether to control the central air conditioning system to operate at full capacity based on the central air conditioning system's operating mode, the second quantity, and the compressor's operating time, or based on the central air conditioning system's operating mode, the second quantity and the first quantity, and the compressor's operating time. Full capacity operation can mean controlling all indoor units that are communicating normally with the outdoor unit to start operating, controlling the expansion valve opening of the indoor units that are communicating normally with the outdoor unit to the maximum or reach a preset opening, and controlling the compressor's operating power to the maximum or reach a preset power.

[0101] During the operation of a central air conditioning system, the compressor's lubricating oil is discharged from the compressor through the refrigerant gas and enters the interior of the central air conditioning system's evaporator, piping, condenser, etc. By bringing this part of the lubricating oil back into the compressor, the dynamic balance of the compressor's lubricating oil can be maintained, preventing the compressor from being damaged due to insufficient oil. Controlling the central air conditioning system to operate at full capacity can improve its reliability.

[0102] If a central air conditioning unit is missing for a period of time, the missing unit may contain refrigerant. To ensure the reliability of the unit, after the missing unit is restored and the compressor of the unit is restarted, the entire central air conditioning system can be turned on at full capacity, and oil recovery can be controlled.

[0103] When the central air conditioning is in cooling mode, and the duration of the first indoor unit's absence is greater than or equal to the first absence duration threshold and the compressor's operating time is greater than or equal to the first operating time threshold, the central air conditioning is controlled to operate at full capacity. The first indoor unit absence confirmation time is the moment when the second quantity is first confirmed to be greater than or equal to the indoor unit absence quantity threshold, and the first indoor unit absence duration is the duration between the current moment and the first indoor unit absence confirmation time.

[0104] For example, if the central air conditioning system is operating in cooling mode, the confirmation time for the first missing indoor unit is the moment when the second quantity is first confirmed to be greater than or equal to the threshold for the number of missing indoor units. That is, when it is determined that the second quantity A ≥ the threshold C for the number of missing indoor units, the current system time is recorded as the confirmation time for the first missing indoor unit. The duration of the first missing indoor unit is calculated as the duration between the current time and the confirmation time for the first missing indoor unit (within the duration of the first missing indoor unit, the central air conditioning system can be in an operating or stopped state). The current time can be the current system time of the central air conditioning system.

[0105] When the confirmation time of the first indoor unit's absence is greater than or equal to the first absence duration threshold T1 (T1 can be 2 hours, etc.), and the compressor's running time is greater than or equal to the first running time threshold T2 (T2 can be 5 minutes, etc.), the central air conditioning system is controlled to operate at full capacity. For example, controlling the central air conditioning system to operate at full capacity can mean controlling all normally functioning indoor units to run for a period of time to ensure normal compressor lubricant recovery and improve the reliability of the central air conditioning system.

[0106] When the central air conditioning is in heating mode, and the duration of the second indoor unit's absence is greater than or equal to the second absence duration threshold, and the compressor's operating time is greater than or equal to the second operating time threshold, the central air conditioning is controlled to operate at full capacity. The duration of the second indoor unit's absence is the time between the current moment and the moment the second indoor unit's absence is confirmed. The moment the second indoor unit's absence is confirmed is the moment when the difference between the second quantity and the first quantity is first confirmed to be greater than or equal to the threshold for the number of indoor units missing.

[0107] For example, if the central air conditioning system is operating in heating mode, the confirmation time for the second missing indoor unit is the moment when the difference between the second quantity and the first quantity is confirmed to be greater than or equal to the threshold for the number of missing indoor units. That is, when it is determined that the difference D between the second quantity A and the first quantity B is greater than or equal to the threshold C for the number of missing indoor units, the current system time is recorded as the confirmation time for the second missing indoor unit. The duration of the second missing indoor unit is calculated as the duration between the current time and the confirmation time (during the duration of the second missing indoor unit, the central air conditioning system is either running or stopped). The current time can be the current system time of the central air conditioning system.

[0108] When the duration of the second indoor unit's absence is greater than or equal to the second absence duration threshold T2 (T2 can be 3 hours, etc.), and the compressor's operating time is greater than or equal to the second operating time threshold T3 (T3 can be 45 minutes, etc.), the central air conditioning system will be controlled to operate at full capacity. For example, all normally functioning indoor units will be controlled to run for a period of time to ensure normal compressor lubricant recovery and improve the reliability of the central air conditioning system.

[0109] By controlling whether the central air conditioning system is fully operational in cooling or heating mode and after restarting, based on the duration of the missing indoor unit, the number of missing indoor units, and the operating time of the compressor, the recovery of the compressor's lubricating oil can be ensured, thereby improving the reliability of the central air conditioning system and guaranteeing its operational safety.

[0110] The central air conditioning control method disclosed herein calculates the number of missing indoor units based on the unit's operating mode, the communication status between the indoor and outdoor units, and the opening degree of the throttling device of the indoor units. It then controls the operation or shutdown of the central air conditioning system in conjunction with the unit's operating status. This allows other indoor units to operate normally even when some are missing, without affecting the overall operation of the central air conditioning system, thus ensuring operational safety and improving its reliability. Furthermore, by controlling the restart of the central air conditioning system based on the number of missing indoor units in cooling or heating mode, and then controlling whether the central air conditioning system operates at full capacity after restarting based on the duration and number of missing indoor units and the compressor's operating time, it ensures the recovery of compressor lubricating oil, further improving the reliability of the central air conditioning system.

[0111] In one embodiment, such as Figure 6 As shown, this disclosure provides a control device 60 for a central air conditioning system, including an indoor unit missing determination module 61 and a control execution module 62. The indoor unit missing determination module 61 determines whether an indoor unit is a first missing indoor unit based on the central air conditioning system's operating mode, the communication status between the indoor and outdoor units, and the opening information of the indoor unit's throttling device, and counts a first number of all first missing indoor units. The control execution module 62 performs control processing on the central air conditioning system based on its operating mode, the first number, and its operating parameters.

[0112] In one embodiment, when the communication between the indoor unit and the outdoor unit is interrupted, the indoor unit missing determination module 61 obtains the opening information of the throttling device before the communication interruption; the indoor unit missing determination module 61 determines whether the indoor unit is the first missing indoor unit based on the central air conditioning operating mode and opening information.

[0113] For example, if the central air conditioner is in cooling mode and the opening information is not zero, the indoor unit missing determination module 61 determines the indoor unit as the first missing indoor unit. If the central air conditioner is in heating mode and the opening information is greater than the opening threshold, the indoor unit missing determination module 61 determines the indoor unit as the first missing indoor unit.

[0114] In one embodiment, when the central air conditioning system is operating in cooling mode and the cooling alarm shutdown conditions are met, the control execution module 62 performs alarm processing and controls the central air conditioning system to shut down. The cooling alarm shutdown conditions include: a first quantity greater than or equal to a threshold for the number of missing indoor units, compressor exhaust temperature less than a low exhaust temperature threshold, compressor suction pressure less than a system low pressure threshold, and average superheat greater than a target superheat for a duration greater than or equal to a first duration threshold. When the central air conditioning system is operating in cooling mode and the cooling alarm shutdown conditions are not met, the control execution module 62 controls the central air conditioning system to operate.

[0115] When the central air conditioning system is in heating mode and the heating alarm shutdown conditions are met, the control execution module 62 performs alarm processing and controls the central air conditioning system to shut down. The heating alarm shutdown conditions include: a first quantity greater than or equal to a threshold for the number of missing indoor units, a compressor exhaust temperature greater than a high exhaust temperature threshold, a compressor suction pressure less than a system low pressure threshold, and a compressor exhaust pressure less than or equal to an exhaust pressure threshold with a duration greater than or equal to a second duration threshold. When the central air conditioning system is in heating mode and the heating alarm shutdown conditions are not met, the control execution module 62 controls the central air conditioning system to operate.

[0116] In one embodiment, such as Figure 7 As shown, the central air conditioning control device 60 also includes a restart control module 63 and an oil return control module 64. After controlling the central air conditioning to stop and receiving a unit start command, the indoor unit missing determination module 61 determines whether the indoor unit is a second missing indoor unit based on the communication status between the indoor and outdoor units, and counts the second number of all second missing indoor units, as well as the first number. The indoor unit missing determination module 61 can determine that an indoor unit is a second missing indoor unit even if communication between the indoor and outdoor units is interrupted.

[0117] The restart control module 63 determines whether to control the central air conditioning to restart based on the central air conditioning's operating mode and the second quantity, or based on the central air conditioning's operating mode, the second quantity, and the first quantity.

[0118] For example, if the central air conditioner is in cooling mode and the cooling start conditions are met, the restart control module 63 determines to restart the central air conditioner; the cooling start conditions include: the second quantity is less than the threshold of the number of missing indoor units.

[0119] When the central air conditioner is in heating mode and the heating start-up conditions are met, the restart control module 63 determines to restart the central air conditioner. The conditions for restarting heating include: the difference between the second quantity and the first quantity is less than the threshold for the number of missing indoor units.

[0120] In one embodiment, after the central air conditioning system restarts, the oil return control module 64 determines whether to control the central air conditioning system to operate at full capacity based on the central air conditioning system's operating mode, the second quantity, and the compressor's operating time, or based on the central air conditioning system's operating mode, the second quantity and the first quantity, and the compressor's operating time.

[0121] For example, when the central air conditioning is in cooling mode and the duration of the first indoor unit's absence is greater than or equal to a first absence duration threshold and the compressor's operating time is greater than or equal to a first operating time threshold, the oil return control module 64 determines to control the central air conditioning to operate at full capacity. Here, the duration of the first indoor unit's absence is the time between the current moment and the moment when the first indoor unit's absence is confirmed; the moment when the first indoor unit's absence is confirmed is the moment when the second quantity is first confirmed to be greater than or equal to the threshold for the number of indoor units missing.

[0122] When the central air conditioning system is in heating mode and the duration of the second indoor unit's absence is greater than or equal to the second absence duration threshold and the compressor's operating time is greater than or equal to the second operating time threshold, the oil return control module 64 determines to control the central air conditioning system to operate at full capacity. The duration of the second indoor unit's absence is the time between the current moment and the moment when the second indoor unit's absence is confirmed. The moment when the second indoor unit's absence is confirmed is the moment when the difference between the second quantity and the first quantity is first confirmed to be greater than or equal to the threshold for the number of indoor units missing.

[0123] In one embodiment, such as Figure 8 As shown, the control device for a central air conditioning system may include a memory 801, a processor 802, a communication interface 803, and a bus 804. The memory 801 is used to store instructions, and the processor 802 is coupled to the memory 801. The processor 802 is configured to execute the aforementioned control method for the central air conditioning system based on the instructions stored in the memory 801.

[0124] The memory 801 can be a high-speed RAM, non-volatile memory, or a memory array. The memory 801 may also be divided into blocks, and these blocks can be combined into virtual volumes according to certain rules. The processor 802 can be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the central air conditioning control method of this disclosure.

[0125] In one embodiment, this disclosure provides a central air conditioning system, including a control device for the central air conditioning system as described in any of the above embodiments. The control device for the central air conditioning system can be deployed in various ways; for example, the control device can be set up independently or it can be set up in the outdoor unit and integrated with the outdoor unit controller.

[0126] In one embodiment, this disclosure provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the method as described in any of the above embodiments.

[0127] The central air conditioning control method, device, central air conditioning unit, and storage medium in the above embodiments can count the number of missing indoor units based on the operating mode, the communication status between the indoor and outdoor units, and the opening degree of the throttling device of the indoor unit. Combined with the operating conditions, they can control the operation or shutdown of the multi-split system. This allows other indoor units to operate normally even when some are missing, without affecting the overall operation of the central air conditioning system, ensuring operational safety and improving its reliability. By controlling the restart of the central air conditioning system based on the number of missing indoor units in cooling or heating mode, and then controlling whether the central air conditioning system operates at full capacity based on the duration and number of missing indoor units and the compressor's operating time after restarting, the recovery of compressor lubricating oil can be ensured, further improving the reliability of the central air conditioning system. This meets user needs and enhances the user experience.

[0128] The methods and systems of this disclosure can be implemented in many ways. For example, they can be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this disclosure are not limited to the order specifically described above, unless otherwise specifically stated. Furthermore, in some embodiments, this disclosure may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this disclosure. Thus, this disclosure also covers recording media storing programs for performing the methods according to this disclosure.

[0129] The description in this disclosure is provided for illustrative and descriptive purposes only and is not intended to be exhaustive or to limit the disclosure to its forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of this disclosure and to enable those skilled in the art to understand this disclosure and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for controlling a central air conditioning system, the central air conditioning system comprising an outdoor unit and an indoor unit, the method comprising: Based on the central air conditioning operating mode, the communication status between the indoor unit and the outdoor unit, and the opening information of the throttling device of the indoor unit, determine whether the indoor unit is the first missing indoor unit, and count the first number of all first missing indoor units. Based on the operating mode of the central air conditioning system, the first quantity, and the operating parameters of the central air conditioning system, control processing is performed on the central air conditioning system. The operating parameters include the compressor discharge temperature and compressor suction pressure of the outdoor unit, and the average superheat of the indoor unit in cooling operation; When the central air conditioner is in cooling mode and the cooling alarm shutdown conditions are met, an alarm is triggered and the central air conditioner is shut down. The cooling alarm shutdown conditions include the following options: the first quantity is greater than or equal to the indoor unit missing quantity threshold, the compressor exhaust temperature is less than the exhaust low temperature threshold, the compressor suction pressure is less than the system low pressure threshold, and the average superheat is greater than the target superheat and the duration is greater than or equal to the first duration threshold.

2. The method as described in claim 1, wherein, The step of determining whether the indoor unit is the first missing indoor unit based on the operating mode of the central air conditioning system, the communication status between the indoor unit and the outdoor unit, and the opening information of the throttling device of the indoor unit includes: If it is determined that the communication between the indoor unit and the outdoor unit is interrupted, obtain the opening information of the throttling device before the communication interruption; Based on the central air conditioning's operating mode and the opening information, it is determined whether the indoor unit is the first missing indoor unit.

3. The method as described in claim 2, wherein, The step of determining whether the indoor unit is the first missing indoor unit based on the central air conditioning's operating mode and the opening information includes: If the central air conditioner is in cooling mode and the opening information is not 0, the indoor unit is determined to be the first missing indoor unit.

4. The method of claim 2, wherein, The step of determining whether the indoor unit is the first missing indoor unit based on the central air conditioning's operating mode and the opening information includes: If the central air conditioner is in heating mode and the opening information is greater than the opening threshold, the indoor unit is determined to be the first missing indoor unit.

5. The method of claim 1, comprising: When the central air conditioning is in cooling mode and the cooling alarm shutdown conditions are not met, the central air conditioning is controlled to operate.

6. The method of claim 1, wherein, The operating parameters include: the compressor exhaust temperature, compressor suction pressure, and compressor exhaust pressure of the outdoor unit; the control processing of the central air conditioning system based on the operating mode, the first quantity, and the operating parameters of the central air conditioning system includes: When the central air conditioner is in heating mode and the heating alarm shutdown conditions are met, an alarm is triggered and the central air conditioner is shut down. The heating alarm shutdown conditions include all of the following options: the first quantity is greater than or equal to the indoor unit missing quantity threshold, the compressor exhaust temperature is greater than the exhaust high temperature threshold, the compressor suction pressure is less than the system low pressure threshold, and the compressor exhaust pressure is less than or equal to the exhaust pressure threshold and the duration is greater than or equal to the second duration threshold.

7. The method of claim 6, comprising: When the central air conditioning system is in heating mode and the heating alarm shutdown conditions are not met, the operation of the central air conditioning system is controlled.

8. The method according to any one of claims 4 to 7, further comprising: After controlling the central air conditioning to stop and receiving the unit start command, based on the communication status between the indoor unit and the outdoor unit, determine whether the indoor unit is the second missing indoor unit, and count the second number of all second missing indoor units and the first number. Whether to control the central air conditioning to restart is determined based on the central air conditioning's operating mode and the second quantity, or based on the central air conditioning's operating mode, the second quantity, and the first quantity.

9. The method of claim 8, wherein determining whether to control the central air conditioning system to restart includes: If the central air conditioner is in cooling mode and the cooling start conditions are met, then the central air conditioner is restarted. The cooling start condition includes: the second quantity is less than the threshold for the number of missing indoor units.

10. The method of claim 8, wherein determining whether to control the central air conditioning system to restart includes: If the central air conditioning system is in heating mode and the heating start-up conditions are met, then the central air conditioning system is restarted. The heating start-up condition includes: the difference between the second quantity and the first quantity is less than the threshold for the number of missing indoor units.

11. The method of claim 8, wherein determining whether the indoor unit is the second missing indoor unit based on the communication status between the indoor unit and the outdoor unit comprises: If it is determined that the communication between the indoor unit and the outdoor unit is interrupted, the indoor unit is determined to be the second missing indoor unit.

12. The method of claim 8, further comprising: After the central air conditioning is restarted, it is determined whether to control the central air conditioning to operate at full capacity based on the central air conditioning's operating mode, the second quantity, and the compressor's operating time, or based on the central air conditioning's operating mode, the second quantity and the first quantity, and the compressor's operating time.

13. The method as described in claim 12, wherein determining whether to control the central air conditioning system to operate at full capacity includes: If the central air conditioning is in cooling mode and the first indoor unit is missing for a duration greater than or equal to a first missing duration threshold, and the compressor's operating time is greater than or equal to a first operating time threshold, then the central air conditioning is controlled to operate at full capacity. Wherein, the first internal unit missing duration is the duration between the current time and the first internal unit missing confirmation time; the first internal unit missing confirmation time is the moment when the second quantity is first confirmed to be greater than or equal to the internal unit missing quantity threshold.

14. The method as described in claim 12, wherein determining whether to control the central air conditioning system to operate at full capacity includes: If the central air conditioner is in heating mode and the second indoor unit is missing for a duration greater than or equal to a second missing duration threshold, and the compressor's operating time is greater than or equal to a second operating time threshold, then the central air conditioner is controlled to operate at full capacity. Wherein, the second internal unit missing duration is the duration between the current time and the second internal unit missing confirmation time; the second internal unit missing confirmation time is the moment when it is first confirmed that the difference between the second quantity and the first quantity is greater than or equal to the internal unit missing quantity threshold.

15. A control device for a central air conditioning system, the central air conditioning system comprising an outdoor unit and an indoor unit, the control device comprising: The indoor unit missing determination module is used to determine whether the indoor unit is the first missing indoor unit based on the operation mode of the central air conditioner, the communication status between the indoor unit and the outdoor unit, and the opening information of the throttling device of the indoor unit, and to count the first number of all first missing indoor units. The control execution module is used to perform control processing on the central air conditioner based on the central air conditioner's operating mode, the first quantity, and the central air conditioner's operating parameters. The operating parameters include the compressor discharge temperature and compressor suction pressure of the outdoor unit, and the average superheat of the indoor unit in cooling operation; The control execution module is specifically used to perform alarm processing and control the central air conditioner to shut down when the central air conditioner is in cooling mode and the cooling alarm shutdown conditions are met; wherein, the cooling alarm shutdown conditions include all of the following options: the first quantity is greater than or equal to the indoor unit missing quantity threshold, the compressor exhaust temperature is less than the exhaust low temperature threshold, the compressor suction pressure is less than the system low pressure threshold, and the average superheat is greater than the target superheat and the duration is greater than or equal to the first duration threshold.

16. A control device for a central air conditioning system includes: Memory; And a processor coupled to the memory, the processor being configured to perform the method as described in any one of claims 1 to 14 based on instructions stored in the memory.

17. A central air conditioning system, comprising: The control device for a central air conditioning system as described in claim 15 or 16.

18. A computer-readable storage medium storing computer instructions that are executed by a processor according to any one of claims 1 to 14.

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