Multi-connection fault detection method, device and air conditioner

Abstract

The present invention provides a multi-split fault detection method and a multi-split system. The multi-split fault detection method includes S1: when the multi-split system is running stably and the external unit load percentage is less than a preset value, obtaining the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each indoor unit; S2: detecting and judging whether the indoor unit pipe temperature is too high and the expansion valve opening is abnormal and counting, and performing fault detection according to the proportion of abnormal indoor units. The present invention divides system faults into different situations based on the heat exchanger pipe temperature and the proportion of indoor units with abnormal expansion valve opening, and makes judgments based on parameters such as the temperature and superheat of the heat exchangers in the outdoor and indoor units, focusing on load ratio, refrigeration capacity charge, valve component, and temperature sensor failure problems, thereby improving the self-diagnosis capability of the multi-split system with poor performance; helping to timely discover problems during the debugging and installation process, and reducing customer complaints caused by unit losses in later operation.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a multi-connected fault detection method, device and air conditioner. Background Art

[0002] Multi-split systems typically consist of one outdoor unit connected to multiple indoor units. By controlling individual indoor units, they can cool or heat the indoor environment, becoming increasingly important for improving people's living and working environments. However, due to the numerous pipes and valves involved and the complex structure, multi-split systems often suffer from poor overall temperature control, resulting in a poor user experience.

[0003] The existing technology typically shuts down a multi-split system and manually checks each system one by one to troubleshoot faults, which is time-consuming, labor-intensive, and has low accuracy. For example, application number 201711289819.4 discloses a multi-split intelligent optimization operation method and device, including: step S1, setting a target subcooling value tsc1 and an outlet pipe temperature setting value t1 for the indoor unit to be tested; step S2, obtaining the subcooling value tsc and the outlet pipe temperature to of the indoor unit; step S3, comparing the subcooling value tsc with the target subcooling value tsc1, and the outlet pipe temperature to with the outlet pipe temperature setting value t1. When tsc < tsc1 and to < t1, adaptive adjustment is performed and faults such as pipeline blockage, electronic expansion valve abnormality, and refrigerant shortage are determined. However, the above solution is prone to misjudgment in situations such as excessive refrigerant or abnormal temperature sensing package.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The problem solved by the present invention is that the existing fault identification method for a multi-connected system with poor overall temperature control effect is prone to misjudgment, missed judgment and is time-consuming.

[0006] To solve the above problems, the present invention provides a multi-split fault detection method, wherein the multi-split system includes an external unit and N internal units, including: S1, when the multi-split system operates stably and the external unit load percentage is less than a preset value, obtaining the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each internal unit; S2, detecting and judging whether the pipe temperature of the internal unit is too high and the expansion valve opening is abnormal and counting, and performing fault detection according to the proportion of abnormal internal units.

[0007] Preferably, step S1 includes:

[0008] S11, respectively detect the total load Q at time t and t-1 t , Q t-1 , when calculating (Q t -Q t-1 ) / Q t <Duration of A1 t1>t预1 Enter step S12, where the value of A1 is 5-6%, t 预1 The value is 15-25min;

[0009] S12, determine whether Q t外 <A2*Q 额 And the duration t2>t 预2 , where A2 is 60-75%, Q 外 is the real-time load of the outdoor unit, Q 额 is the rated load of the outdoor unit, t 预2 The value of is 10-20min. If so, obtain the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each indoor unit; if not, return to step S11.

[0010] Preferably, step S2 includes:

[0011] S21, detect the pipe temperature T of each indoor unit 管 When the tube temperature T 管 >T0, then N 管异 =N 管异 +1, where N 管异 is the number of indoor units with abnormal pipe temperature, T0 is the preset temperature in cooling or heating mode;

[0012] S22, determine whether N 管异 / N>B1, wherein B1>50%, if yes, proceed to step S23; if no, proceed to step S24;

[0013] S23, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening, the value of B2 is greater than 50%, if so, the load Q of the indoor unit and outdoor unit is detected respectively. 内 , Q 外 To make adjustments based on the over-allocation situation; if not, exit the current test;

[0014] S24, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening and the value of B2 are greater than 50%. If so, further determine whether there is too much or too little refrigerant; if not, proceed to step S25;

[0015] S25. Determine whether there is a blockage or an abnormality in the temperature sensor.

[0016] Preferably, if the heating mode is selected in step S21, the pipe temperature T 管 The outlet temperature of the heat exchanger of the indoor unit is Te1 and T0 is 30℃; if it is in cooling mode, the pipe temperature T 管 The heat exchanger inlet pipe temperature Te2 represents the indoor unit and T0 is 35℃.

[0017] Preferably, the adjustment according to the over-allocation situation in step S23 is specifically as follows:

[0018] S231, determine whether Q 内 / Q 外 <125, if yes, proceed to step S232; if no, sort the indoor units according to their target loads and shut down the indoor unit with the smallest target load;

[0019] S232, determine whether Q 内 / Q 外 <110, if yes, it is determined that there is no over-capacity problem in the multi-split system; if not, the fan speeds of the outdoor and indoor units are increased at the same time.

[0020] Preferably, the condition for judging the lack of refrigerant in step S24 is: if the indoor unit is running in cooling mode, when the expansion valve opening EEV of the indoor unit is abnormal and P d -T lo ≤T 预1 , where T 预1 3-8℃; or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and P d -T ao <T 预2 And T s -T ao <T 预3 , where P d is the high pressure temperature of the external unit, T lo is the outlet temperature of the heat exchanger of the outdoor unit, T ao is the external ambient temperature, T s is the low pressure temperature of the outdoor unit, T 预2 The value of T is 30-35℃, 预3 The value is 10-15℃.

[0021] Preferably, the condition for determining whether the expansion valve opening EEV is normal is: if T ao <10℃ and EEV≤350pls or 10℃≤T ao <40℃ and 100≤EEV<250, or 40℃≤T ao And when 100≤EEV<250, it indicates that the opening of the indoor unit's expansion valve is normal.

[0022] Preferably, the judgment condition for excessive refrigerant in step S24 is: if the indoor unit is running in cooling mode, when the expansion valve opening EEV is abnormal and P d -T lo ≤T 预4 And P d ≥T 预5 ; Or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and T em <T d -T 预6 And P d ≥T 预7 , where T em is the average middle tube temperature of the internal unit, T 预4 、T 预5 、T 预6 、T 预7 The value ranges are 10-20℃, 58-62℃, 15-18℃, and 48-52℃ respectively.

[0023] Preferably, step S25 includes:

[0024] S251, determine whether the expansion valve opening EEV of the indoor unit is greater than C 预1 And T e1 -T ai ≤T 预8 , where T ai is the indoor ambient temperature, C 预1 、T 预8 The values ​​are 450-500pls and 0-5℃ respectively. If so, when Q 实 / Q 理 When <A3, it is determined that there is a blockage in the indoor unit and the indoor unit is shut down. 实 , Q 理 Represent the actual cooling capacity and theoretical cooling capacity of the indoor unit respectively, and the value range of A3 is 15-25%; if not, go to step S252;

[0025] S252, sort the indoor units according to the target load, detect the target superheat of abnormal indoor units and their adjacent indoor units, and check the target superheat of abnormal indoor units and their adjacent indoor units every t i Duration detection ΔT 1i , ΔT 2i And calculate T i =|ΔT 1i -ΔT 2i |,t k After the time is up, determine whether (T1+T2+..+T k ) / k≥2-4℃, where t k =k*t i, ΔT1 is the target superheat of the normal indoor unit, and ΔT2 is the target superheat of the abnormal indoor unit. If so, it is determined that the temperature sensing package of the abnormal indoor unit is faulty.

[0026] Compared with the prior art, the multi-split system fault detection method of the present invention has the following beneficial effects: 1) The present invention divides the proportion of internal units with abnormal tube temperature and expansion valve opening of the heat exchanger into different situations, and makes judgments based on parameters such as high and low pressure temperature and superheat of the outdoor heat exchanger, focusing on load ratio, refrigeration capacity filling amount, valve components, and temperature sensor failure problems, thereby improving the self-troubleshooting capability of the multi-split system with poor effect; 2) It helps to discover problems in a timely manner during the debugging and installation process, and reduce customer complaints caused by losses of the units in later operation; 3) The changes to the existing multi-split system are small, which is convenient for promotion and implementation.

[0027] The present invention also provides a multi-connected system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the multi-connected system fault detection method described above is implemented. The multi-connected system has the same beneficial effects as the multi-connected system fault detection method, which are not described in detail here. The present invention also provides a readable storage medium having the computer program stored thereon. When the processor executes the computer program, the multi-connected system fault detection method described above is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of the multi-connection fault detection method according to Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the multi-connection fault detection method described in Example 2 of the present invention. DETAILED DESCRIPTION

[0030] To make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. The technical features in the embodiments of the present invention can be combined with each other without conflict.

[0031] Unless otherwise clearly stipulated and limited, the terms such as "install", "set", "connect", "fix", "screw", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0032] The multi-connected system can run multiple indoor units simultaneously to achieve temperature regulation in various scenarios such as shopping malls, which can improve the comfort of users in the place they are in. When a fault occurs, it may affect the temperature regulation effect of the entire system. If manual troubleshooting is time-consuming, it is not conducive to rapid maintenance. To this end, the applicant proposes the following technical solution:

[0033] Example 1

[0034] like Figure 1 As shown, a multi-split fault detection method, wherein the multi-split system includes one external unit and N internal units, includes:

[0035] S1. When the VRF system is running stably and the load percentage of the external unit is less than a preset value, obtain the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each internal unit;

[0036] Preferably, step S1 includes:

[0037] S11, respectively detect the total load Q at time t and t-1 t , Q t-1 , when calculating (Q t -Q t-1 ) / Q t <Duration of A1 t1>t 预1 Enter step S12, where the value of A1 is 5-6%, t 预1 The value of is 15-25min; preferably, the N indoor machines are all in operation.

[0038] S12, determine whether Q 外 <A2*Q 额 And the duration t2>t 预2 , where A2 is 60-75%, Q 外 is the real-time load of the outdoor unit, Q 额 is the rated load of the outdoor unit, t 预2 The value of is 10-20min. If so, obtain the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each indoor unit; if not, return to step S11.

[0039] When the multi-split system is running stably, the external unit load percentage can be used to judge and confirm whether there is any abnormality in the multi-split system, such as poor cooling and heating effects, which can improve the accuracy of fault judgment.

[0040] S2. Detect and determine whether the pipe temperature of the indoor unit is too high and the expansion valve opening is abnormal, and count them. Perform fault detection based on the proportion of abnormal indoor units.

[0041] Preferably, the multi-connection fault detection method further includes: S0, N indoor units are all started and running. t外 The proportion of the multi-connected system can more accurately reflect whether there is an abnormality in the multi-connected system.

[0042] Preferably, step S2 includes:

[0043] S21, detect the pipe temperature T of each indoor unit 管 When the tube temperature T 管 >T0, then N 管异 =N 管异 +1, where N 管异 In case of abnormal pipe temperature, the number of indoor units T0 is the preset temperature in cooling or heating mode;

[0044] If it is heating mode, the pipe temperature T 管 The outlet temperature of the heat exchanger of the indoor unit is Te1 and T0 is 30℃; if it is in cooling mode, the pipe temperature T 管 The heat exchanger inlet pipe temperature Te2 represents the indoor unit and T0 is 35℃.

[0045] S22, determine whether N 管异 / N>B1, wherein B1>50%, if yes, proceed to step S23; if no, proceed to step S24;

[0046] S23, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening, the value of B2 is greater than 50%, if so, the load Q of the indoor unit and outdoor unit is detected respectively. 内 , Q 外 To make adjustments based on the over-allocation situation; if not, exit the current test;

[0047] As an example of the present invention, the adjustment according to the over-allocation situation includes: S231, judging whether Q 内 / Q 外 <125, if yes, go to step S232; if not, sort the indoor units according to their target load and turn off the indoor unit with the smallest target load; S232, determine whether Q 内 / Q 外 <110, if yes, it is determined that there is no over-capacity problem in the multi-split system; if not, the fan speeds of the outdoor and indoor units are increased at the same time.

[0048] When Q 内 / Q 外=110-125, it indicates that the multi-split system is over-provisioned. The system should be adjusted to the strongest gear by adjusting the outdoor unit and the fan speed of the indoor unit. 内 / Q 外 When it is greater than 125, it means that the multi-split system is seriously over-provisioned. At this time, the indoor unit with low load will be shut down in response according to the sorting; then the load ratio of the indoor and outdoor units will be calculated. If it does not meet the requirements, repeat the above steps until the ratio is normal, and exit the troubleshooting mode to ensure the normal operation of the indoor and outdoor units of the existing multi-split system.

[0049] S24, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening and the value of B2 are greater than 50%. If so, further determine whether there is too much or too little refrigerant; if not, enter step S25; the values ​​of B1 and B2 can be the same or different, such as 60%, 70%, 80%, etc.

[0050] As an example of the present invention, the determination condition of whether the expansion valve opening EEV is normal is: if T ao <10℃ and EEV≤350pls or 10℃≤T ao <40℃ and 100≤EEV<250, or 40℃≤T ao And when 100≤EEV<250, it indicates that the opening of the indoor unit's expansion valve is normal.

[0051] The judgment condition of lack of refrigerant is: if the indoor unit is running in cooling mode, when the expansion valve opening EEV of the indoor unit is abnormal and P d -T lo ≤T1, where T1 is 3-8℃; or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and P d -T ao <T2 and T s -T ao <T3, where P d is the high pressure temperature of the external unit, T lo is the outlet temperature of the heat exchanger of the outdoor unit, T ao is the external ambient temperature, T s The low pressure temperature of the outdoor unit, T2 is 30-35℃, and T3 is 10-15℃.

[0052] The judgment condition of excessive refrigerant is: if the indoor unit is running in cooling mode, when the expansion valve opening EEV is abnormal and P d -T lo ≤T4 and Pd ≥T5; or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and T em <T d -T6 and P d ≥T7, where T em is the average middle tube temperature of the indoor unit, and the values ​​of T4, T5, T6, and T7 are 10-20℃, 58-62℃, 15-18℃, and 48-52℃ respectively.

[0053] In cooling mode, T ao >10℃; in heating mode, T ao <10℃; This setting can be judged according to the specific operating mode of the indoor unit to improve the efficiency of fault detection.

[0054] Preferably, when determining whether the refrigerant is too much or too little, the expansion valve opening PMW of the outdoor unit is abnormal, that is, if T ao <-7℃ and 250pls≤PMV≤350pls or 10℃-7℃≤T ao <10℃ and 50≤PMV<250. This setting can quickly and accurately detect faults and further improve the accuracy of detection.

[0055] S25. Determine whether there is a blockage or abnormality in the temperature sensor, including:

[0056] S251, determine whether the expansion valve opening EEV of the indoor unit is greater than C 预1 And T e1 -T ai ≤T 预8 , where T ai is the indoor ambient temperature, C 预1 、T 预8 The values ​​are 450-500pls and 0-5℃ respectively. If so, when Q 实 / Q 理 When <A3, it is determined that there is a blockage in the indoor unit and the indoor unit is shut down. 实 , Q 理 Represent the actual cooling capacity and theoretical cooling capacity of the indoor unit respectively, and the value range of A3 is 15-25%; if not, go to step S252;

[0057] S252, sort the indoor units according to the target load, detect the target superheat of abnormal indoor units and their adjacent indoor units, and check the target superheat of abnormal indoor units and their adjacent indoor units every t i Duration detection ΔT 1i , ΔT 2i And calculate T i =|ΔT 1i -ΔT 2i |,t k After the time is up, determine whether (T1+T2+..+Tk ) / k≥2-4℃, where t k =k*t i , ΔT1 is the target superheat of a normal indoor unit, and ΔT2 is the target superheat of an abnormal indoor unit. If both are true, the temperature sensor of the abnormal indoor unit is determined to be faulty. If the temperature sensor is faulty, the expansion valve opening is temporarily adjusted by correcting the target superheat of the abnormal indoor unit, and the address of the faulty indoor unit is returned.

[0058] The multi-split system fault detection method described in the present invention divides different situations into different situations according to the proportion of internal units with abnormal tube temperature and expansion valve opening of the heat exchanger, and makes judgments based on parameters such as high and low pressure temperature and superheat of the outdoor heat exchanger, focusing on load ratio, refrigeration capacity charge, valve components, and temperature sensor package failures, thereby improving the self-troubleshooting capability of poor multi-split system effects; it helps to discover problems in a timely manner during the debugging and installation process, and reduce customer complaints caused by losses in the later operation of the unit.

[0059] Example 2

[0060] like Figure 2 As shown, a multi-split fault detection method, wherein the multi-split system includes one external unit and N internal units, includes:

[0061] S1. When all N indoor units are running, the total load Q at time t and t-1 is detected respectively. t , Q t-1 , when calculating (Q t -Q t-1 ) / Q t <Duration of A1 t1>t 预1 Enter step S2, where the value of A1 is 5-6%, t 预1 The value is 15-25min;

[0062] According to the total load fluctuation at time t and t-1, it can be accurately judged whether the multi-connected system has entered a stable state.

[0063] S2. Determine whether Q t外 <A2*Q 额 And the duration t2>t 预2 , where A2 is 60-75%, Q 外 is the real-time load of the outdoor unit, Q 额 is the rated load of the outdoor unit, t 预1 The value of is 10-20min. If so, obtain the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each indoor unit; if not, return to step S1.

[0064] Judging and confirming abnormalities in the multi-split system and poor cooling and heating effects based on the external unit load percentage can improve the accuracy of fault diagnosis.

[0065] S3. Detect the pipe temperature T of each indoor unit 管 When the tube temperature T 管 >T0, then N 管异 =N 管异 +1, where N 管异 is the number of indoor units with abnormal pipe temperature, T0 is the preset temperature in cooling or heating mode;

[0066] If it is heating mode, the pipe temperature T 管 The outlet temperature of the heat exchanger of the indoor unit is Te1 and T0 is 30℃; if it is in cooling mode, the pipe temperature T 管 The heat exchanger inlet pipe temperature Te2 represents the indoor unit and T0 is 35℃.

[0067] S4, determine whether N 管异 / N>B1, where B1>60%, if yes, go to step S5; if no, go to step S6;

[0068] S5, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening, the value of B2 is greater than 50%, if so, the load Q of the indoor unit and outdoor unit is detected respectively. 内 , Q 外 To make adjustments based on the over-allocation situation; if not, exit the current test;

[0069] When Q 内 / Q 外 When Q>125, the multi-split system is seriously over-provisioned. Calculate the target load of the indoor units and sort them, then shut down the indoor unit with the smallest target load to respond. Then calculate the load ratio of the indoor and outdoor units. If it does not meet the requirements, repeat the above steps until the ratio is normal. Exit the troubleshooting mode to ensure the normal operation of the indoor and outdoor units of the existing multi-split system. When 110≤Q 内 / Q 外 When it is less than 125, it indicates that the multi-split system is over-provisioned. The system can be responded to by adjusting the outdoor and indoor units in the multi-split system to the strongest gear and increasing the fan speed of the indoor unit.

[0070] S6, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening and the value of B2 are greater than 50%. If so, proceed to step S7; if not, proceed to step S9;

[0071] As an example of the present invention, the determination condition of whether the expansion valve opening EEV is abnormal is: if T ao <10℃ and EEV≤350pls or 10℃≤T ao <40℃ and 100≤EEV<250, or 40℃≤T ao When 100≤EEV<250, it indicates that the expansion valve opening of the indoor unit is normal. The values ​​of B1 and B2 can be the same or different, such as 60%, 70%, 80%, etc.

[0072] S7, if the indoor unit is running in cooling mode, when the expansion valve opening EEV of the indoor unit is abnormal and P d -T lo ≤T 预1 , where T 预1 3-8℃; or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and P d -T ao <T 预2 And T s -T ao <T 预3 , where P d is the high pressure temperature of the external unit, T lo is the outlet temperature of the heat exchanger of the outdoor unit, T ao is the external ambient temperature, T s is the low pressure temperature of the outdoor unit, T 预2 The value of T is 30-35℃, 预3 The value is 10-15℃.

[0073] S8, if the indoor unit is running in cooling mode, when the expansion valve opening EEV is abnormal and P d -T lo ≤T 预4 And P d ≥T 预5 ; Or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and T em <T d -T 预6 And P d ≥T 预7 , it means that there is too much refrigerant in the multi-split system, where T em is the average middle tube temperature of the internal unit, T 预4 、T 预5 、T 预6 、T 预7 The value ranges are 10-20℃, 58-62℃, 15-18℃, and 48-52℃ respectively.

[0074] Preferably, in cooling mode Tao >10℃; in heating mode, T ao <10℃; This setting can be judged according to the specific operating mode of the indoor unit to improve the efficiency of fault detection. Preferably, when the refrigerant is too much or too little, the expansion valve opening PMW of the outdoor unit is abnormal, that is: when T ao <-7℃ and 250pls≤PMV≤350pls or 10℃-7℃≤T ao <10℃ and 50≤PMV<250. This setting can quickly and accurately detect faults and further improve the accuracy of detection.

[0075] S9, determine whether the expansion valve opening EEV of the indoor unit is greater than C 预1 And T e1 -T ai ≤T 预8 , where T ai is the indoor ambient temperature, C 预1 、T 预8 The values ​​are 450-500pls and 0-5℃ respectively. If so, when Q 实 / Q 理 When <A3, it is determined that there is a blockage in the indoor unit and the indoor unit is shut down. 实 , Q 理 Represent the actual cooling capacity and theoretical cooling capacity of the indoor unit respectively, and the value range of A3 is 15-25%; if not, go to step S10;

[0076] S10, sort the indoor units according to the target load, detect the target superheat of abnormal indoor units and their adjacent indoor units, and check the target superheat of abnormal indoor units and their adjacent indoor units every t i Duration detection ΔT 1i , ΔT 2i And calculate T i =|ΔT 1i -ΔT 2i |,t k After the time is up, determine whether (T1+T2+..+T k ) / k≥2-4℃, where t i =k*t i , ΔT1 is the target superheat of the normal indoor unit, and ΔT2 is the target superheat of the abnormal indoor unit. If so, it is determined that the temperature sensing package of the abnormal indoor unit is faulty.

[0077] When the temperature sensor fails, the expansion valve opening is temporarily adjusted by correcting the target superheat of the abnormal indoor unit, and the address of the faulty indoor unit is returned at the same time.

[0078] Example 3

[0079] The present invention also provides an air conditioner, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the multi-connection fault detection method is implemented.

[0080] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the multi-connection fault detection method described above is implemented. The computer-readable storage medium can be a readable storage medium or a readable signal medium, and can be the same as the storage unit described above, for example: a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk, etc. In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0081] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for detecting faults in a multi-connected system, wherein the multi-connected system includes one external unit and N internal units, characterized in that: include: S1. When the VRF system is running stably and the load percentage of the external unit is less than a preset value, obtain the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each internal unit; S2, detecting and determining whether the pipe temperature of the indoor unit is too high and the expansion valve opening is abnormal and counting, and performing fault detection based on the proportion of abnormal indoor units; Step S2 includes: S21, detect the pipe temperature T of each indoor unit 管 When the tube temperature T 管 >T0, then N 管异 =N 管异 +1, where N 管异 is the number of indoor units with abnormal pipe temperature, T0 is the preset temperature in cooling or heating mode; S22, determine whether N 管异 / N>B1, wherein B1>50%, if yes, proceed to step S23; if no, proceed to step S24; S23, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening, the value of B2 is greater than 50%, if so, the load Q of the indoor unit and outdoor unit is detected respectively. 内 , Q 外 To make adjustments based on the over-allocation situation; if not, exit the current test; S24, detect and judge whether the expansion valve opening EEV of each indoor unit is abnormal. If so, then N 阀异 =N 阀异 +1 and judge whether N 阀异 / N>B2, where N 阀异 The number of indoor units with abnormal expansion valve opening and the value of B2 are greater than 50%. If so, further determine whether there is too much or too little refrigerant; if not, proceed to step S25; S25. Determine whether there is a blockage or an abnormality in the temperature sensor.

2. The multi-connection fault detection method according to claim 1, characterized in that: step S1 includes: S11, respectively detect the total load Q at time t and t-1 t , Q t-1 , when calculating (Q t -Q t-1 ) / Q t <Duration of A1 t1>t 预1 Enter step S12, where the value of A1 is 5-6%, t 预1 The value is 15-25min; S12, determine whether Q t外 <A2*Q 额 And the duration t2>t 预2 , where A2 is 60-75%, Q 外 is the real-time load of the outdoor unit, Q 额 is the rated load of the outdoor unit, t 预2 The value of is 10-20min. If so, obtain the heat exchanger inlet pipe temperature Te2, outlet pipe temperature Te1 and expansion valve opening EEV of each indoor unit; if not, return to step S11.

3. The multi-connection fault detection method according to claim 1, characterized in that: If the heating mode is selected in step S21, the pipe temperature T 管 The outlet temperature of the heat exchanger of the indoor unit is Te1 and T0 is 30℃; if it is in cooling mode, the pipe temperature T 管 The heat exchanger inlet pipe temperature Te2 represents the indoor unit and T0 is 35℃.

4. The multi-connection fault detection method according to claim 1, characterized in that: step The specific adjustments in S23 based on the over-allocation situation are as follows: S231, determine whether Q 内 / Q 外 <125, if yes, proceed to step S232; if no, sort the indoor units according to their target loads and shut down the indoor unit with the smallest target load; S232, determine whether Q 内 / Q 外 <110. If yes, it is determined that there is no over-capacity problem in the multi-split system; if not, the fan speeds of the outdoor and indoor units are increased at the same time.

5. The multi-connection fault detection method according to claim 1, characterized in that: The judgment condition for lack of refrigerant in step S24 is: if the indoor unit is running in cooling mode, when the expansion valve opening EEV of the indoor unit is abnormal and P d -T lo ≤T 预1 , where T 预1 3-8℃; or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and P d -T ao <T 预2 And T s -T ao <T 预3 , where P d is the high pressure temperature of the external unit, T lo is the outlet temperature of the heat exchanger of the outdoor unit, T ao is the external ambient temperature, T s is the low pressure temperature of the outdoor unit, T 预2 The value of T is 30-35℃, 预3 The value is 10-15℃.

6. The multi-connection fault detection method according to claim 5, characterized in that: The conditions for determining whether the expansion valve opening EEV is normal are: if T ao <10℃ and EEV≤350pls or 10℃≤T ao <40℃ and 100≤EEV<250, or 40℃≤T ao And when 100≤EEV<250, it indicates that the opening of the indoor unit's expansion valve is normal.

7. The multi-connection fault detection method according to claim 6, characterized in that: The judgment condition for excessive refrigerant in step S24 is: if the indoor unit is running in cooling mode, when the expansion valve opening EEV is abnormal and P d -T lo ≤T 预4 And P d ≥T 预5 ; Or if the indoor unit is running in heating mode, when the expansion valve opening EEV is abnormal and T em <T d -T 预6 And P d ≥T 预7 , where T em is the average middle tube temperature of the internal unit, T 预4 、T 预5 、T 预6 、T 预7 The value ranges are 10-20℃, 58-62℃, 15-18℃, and 48-52℃ respectively.

8. The multi-connection fault detection method according to any one of claims 5 to 7, characterized in that: Step S25 includes: S251, determine whether the expansion valve opening EEV of the indoor unit is greater than C 预1 And T e1 -T ai ≤T 预8 , where T ai is the indoor ambient temperature, C 预1 、T 预8 The values ​​are 450-500pls and 0-5℃ respectively. If so, when Q 实 / Q 理 When <A3, it is determined that there is a blockage in the indoor unit and the indoor unit is shut down. 实 , Q 理 Represent the actual cooling capacity and theoretical cooling capacity of the indoor unit respectively, and the value range of A3 is 15-25%; if not, go to step S252; S252, sort the indoor units according to the target load, detect the target superheat of abnormal indoor units and their adjacent indoor units, and check the target superheat of abnormal indoor units and their adjacent indoor units every t i Duration detection ΔT 1i , ΔT 2i And calculate T i =|ΔT 1i -ΔT 2i |,t k After the time is up, determine whether (T1+T2+..+T k ) / k≥2-4℃, where t k =k*t i , ΔT1 is the target superheat of the normal indoor unit, and ΔT2 is the target superheat of the abnormal indoor unit. If so, it is determined that the temperature sensing package of the abnormal indoor unit is faulty.

9. A multi-connection system comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the multi-connection fault detection method according to any one of claims 1 to 8 is implemented.

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