Fault estimation device, fault estimation method, air conditioning system, and air conditioner

Abstract

To provide a failure estimation device or the like capable of determining a state of a compressor even during a normal operation and estimating failure without requiring a special operation and device.SOLUTION: A failure estimation device includes: a detection section that detects an actual measurement current value that is an actually measured drive current value for driving a compressor; an acquisition section that acquires a feature amount related to driving of the compressor including the actual measurement current value; and an estimation section that estimates the drive current value corresponding to an operation load of the compressor as an estimation current value by using the feature amount. The failure estimation device further includes a determination section that determines the state of the compressor by using the estimation current value estimated by the estimation section and the actual measurement current value detected by the detection section.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fault estimation device, a fault estimation method, an air conditioning system, and an air conditioner. [Background technology]

[0002] Various methods have been proposed for diagnosing failures in the compressor that circulates the refrigerant in the refrigerant circuit of an air conditioner. For example, a method of diagnosing a compressor failure by performing an oil amount adjustment operation that is different from the normal operation of the refrigerant circuit (Patent Document 1) and a method of diagnosing a compressor failure by incorporating a special detection device in the inverter circuit that drives the compressor (Patent Document 2) are known.

[0003] The method of Patent Document 1 takes into consideration that the input of the compressor changes depending on the condition of the oil that lubricates the compressor, and performs an oil amount adjustment operation to adjust the amount of oil, thereby suppressing variations in the operating state quantity caused by the condition of the oil. After performing the oil amount adjustment operation, the current compressor current value is acquired, and the current compressor current value is compared with the normal compressor current value, and the presence or absence of a compressor failure is diagnosed based on the comparison result.

[0004] In addition, the method of Patent Document 2 uses a detection device to frequency analyze the drive current waveform in the inverter circuit, compares the analysis results under normal conditions with the current analysis results, and diagnoses whether or not the compressor is faulty based on the comparison results. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-98515 [Patent Document 2] Japanese Patent Application Publication No. 2017-221023 Summary of the Invention [Problem to be solved by the invention]

[0006] The diagnostic method of Patent Document 1 requires that an oil amount adjustment operation, which is different from normal operation, be performed to suppress variations in the operating state quantity due to the oil condition. To perform the oil amount adjustment operation, normal operation must be interrupted. This makes it difficult to diagnose the compressor while normal operation is ongoing, and the interruption of normal operation during compressor diagnosis may cause discomfort to users.

[0007] Furthermore, the diagnostic method of Patent Document 2 requires that a detection device be incorporated into the inverter circuit that drives the compressor, making it difficult to diagnose the compressor in an existing air conditioner.

[0008] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a failure estimation device or the like that can determine the state of a compressor and estimate a failure even during normal operation without requiring any special operation or device. [Means for solving the problem]

[0009] A fault estimation device according to one aspect includes a detection unit that detects an actual current value, which is an actual measured drive current value that drives a compressor, an acquisition unit that acquires feature quantities related to compressor drive including the actual measured current value, and an estimation unit that estimates a drive current value corresponding to an operating load of the compressor as an estimated current value using the feature quantities. The fault estimation device further includes a determination unit that determines a state of the compressor using the estimated current value estimated by the estimation unit and the actual measured current value detected by the detection unit. [Effects of the Invention]

[0010] As one aspect, the compressor condition can be determined and a fault can be estimated even during normal operation without requiring any special operation or device. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of an air conditioning system according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram illustrating an example of the air conditioner of the first embodiment. [Figure 3] FIG. 3 is a Mollier diagram showing the refrigeration cycle of the air conditioner. [Figure 4] FIG. 4 is a block diagram illustrating an example of the centralized controller according to the first embodiment. [Figure 5] FIG. 5 is an explanatory diagram showing an example of a normal distribution of ratios. [Figure 6] FIG. 6 is a flowchart illustrating an example of a processing operation of the learning unit related to the learning process of the first embodiment. [Figure 7] FIG. 7 is a flowchart illustrating an example of a processing operation of the centralized controller related to the failure determination processing of the first embodiment. [Figure 8] FIG. 8 is a block diagram illustrating an example of an air conditioning system according to a second embodiment. [Figure 9] FIG. 9 is a block diagram illustrating an example of a centralized controller according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the air conditioning system disclosed in the present application will be described in detail with reference to the drawings. Note that the disclosed technology is not limited to these embodiments. Furthermore, each embodiment described below may be modified as appropriate within the scope of not causing any contradiction. [Example]

[0013] <Air conditioning system configuration> FIG. 1 is an explanatory diagram showing an example of an air conditioning system 100 of a first embodiment. The air conditioning system 100 shown in FIG. 1 includes an air conditioner 1, a server device 110, and a communication network 120. The air conditioner 1 is an air conditioner installed in each location. The server device 110 is a server that generates and manages a learning model of the air conditioner 1 in the air conditioning system 100. The communication network 120 is, for example, a communication network such as the Internet.

[0014] <Air conditioner configuration> Fig. 2 is an explanatory diagram showing an example of an air conditioner 1 according to a first embodiment. The air conditioner 1 shown in Fig. 2 has one outdoor unit 2, N indoor units 3, and a centralized controller 7 (N is a natural number equal to or greater than 2). The outdoor unit 2 is connected to each of the indoor units 3 in parallel via liquid pipes 4 and gas pipes 5. The outdoor unit 2 and the indoor units 3 are connected via refrigerant piping such as the liquid pipes 4 and gas pipes 5, thereby forming a refrigerant circuit 6 of the air conditioner 1.

[0015] <Outdoor unit configuration> The outdoor unit 2 has a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an outdoor unit expansion valve 14, a first shut-off valve 15, a second shut-off valve 16, an accumulator 17, an outdoor unit fan 18, and a first control unit 19. The compressor 11, four-way valve 12, outdoor heat exchanger 13, outdoor unit expansion valve 14, first shut-off valve 15, second shut-off valve 16, and accumulator 17 are connected to each other by refrigerant pipes described in detail below to form an outdoor refrigerant circuit that forms part of the refrigerant circuit 6.

[0016] Compressor 11 is, for example, a high-pressure vessel type variable capacity compressor whose operating capacity can be varied in response to the drive of a motor (not shown) whose rotation speed is controlled by an inverter circuit 11A. A refrigerant discharge side of compressor 11 is connected to a first port 12A of four-way valve 12 by a refrigerant pipe 21. A refrigerant suction side of compressor 11 is also connected to a refrigerant outlet side of accumulator 17 by a refrigerant pipe 22.

[0017] The four-way valve 12 is a valve for switching the flow direction of the refrigerant in the refrigerant circuit 6, and includes first to fourth ports 12A to 12D. The first port 12A is connected to a discharge pipe of the compressor 11 by a refrigerant pipe 21. The second port 12B is connected to one refrigerant inlet / outlet of the outdoor heat exchanger 13 by a refrigerant pipe 23. The third port 12C is connected to a suction port of the compressor 11 by a refrigerant pipe 26. The fourth port 12D is connected to the second stop valve 16 by a refrigerant pipe 24.

[0018] The outdoor heat exchanger 13 is a heat exchanger that exchanges heat between the refrigerant and the outside air that is drawn into the outdoor unit 2 by the rotation of the outdoor unit fan 18. One refrigerant inlet / outlet of the outdoor heat exchanger 13 is connected to the second port 12B of the four-way valve 12 by a refrigerant pipe 23. The other refrigerant inlet / outlet of the outdoor heat exchanger 13 is connected to the first stop valve 15 by a refrigerant pipe 25. The outdoor heat exchanger 13 functions as a condenser when the air conditioner 1 is performing cooling operation, and functions as an evaporator when the air conditioner 1 is performing heating operation.

[0019] The outdoor unit expansion valve 14 is provided in the refrigerant piping 25 and is an electronic expansion valve driven by a pulse motor (not shown). The outdoor unit expansion valve 14 adjusts the amount of refrigerant flowing into or out of the outdoor heat exchanger 13 by adjusting its opening according to the number of pulses given to the pulse motor. When the air conditioner 1 is performing heating operation, the opening of the outdoor unit expansion valve 14 is adjusted so that the refrigerant superheat on the refrigerant suction side of the compressor 11 becomes the target suction refrigerant superheat. When the air conditioner 1 is performing cooling operation, the opening of the outdoor unit expansion valve 14 is fully open.

[0020] The accumulator 17 is connected to the third port 12C of the four-way valve 12 by a refrigerant pipe 26. Furthermore, the accumulator 17 is connected to a refrigerant inlet of the compressor 11 by a refrigerant pipe 22. The accumulator 17 separates the refrigerant that has flowed into the accumulator 17 from the refrigerant pipe 26 into gas refrigerant and liquid refrigerant, and allows only the gas refrigerant to be drawn into the compressor 11.

[0021] The outdoor unit fan 18 is made of a resin material and is disposed near the outdoor heat exchanger 13. The outdoor unit fan 18 takes in outside air from an air inlet (not shown) into the outdoor unit 2 in response to the rotation of a fan motor (not shown), and generates an air flow for discharging the outside air that has exchanged heat with the refrigerant in the outdoor heat exchanger 13 to the outside of the outdoor unit 2 from an air outlet (not shown).

[0022] In addition, a plurality of sensors are arranged in the outdoor unit 2. A discharge pressure sensor 31 that detects the pressure of the refrigerant discharged from the compressor 11 as a discharge pressure value, and a discharge temperature sensor 32 that detects the temperature of the refrigerant discharged from the compressor 11, i.e., the discharge temperature, are arranged in the refrigerant piping 21. A suction pressure sensor 33 that detects the pressure of the refrigerant sucked into the compressor 11 as a suction pressure value, and a suction temperature sensor 34 that detects the temperature of the refrigerant sucked into the compressor 11, i.e., the suction temperature, are arranged near the refrigerant inlet of the accumulator 17 in the refrigerant piping 26.

[0023] A refrigerant temperature sensor 35 is disposed in the refrigerant piping 25 between the outdoor heat exchanger 13 and the outdoor unit expansion valve 14 to detect the temperature of the refrigerant flowing into the outdoor heat exchanger 13 or the temperature of the refrigerant flowing out from the outdoor heat exchanger 13. An outdoor air temperature sensor 36 is disposed near an air inlet (not shown) of the outdoor unit 2 to detect the temperature of the outdoor air flowing into the outdoor unit 2, i.e., the outdoor air temperature.

[0024] The first control unit 19 controls the entire outdoor unit 2. As shown in FIG. 1 , the first control unit 19 has a first communication unit 19A, a first input unit 19B, a first output unit 19C, and a first input / output unit 19D. The first communication unit 19A is an interface, such as a universal asynchronous receiver transmitter (UART), that communicates with the second control unit 50 in the indoor unit 3 or with the centralized controller 7 via the communication network 8. The first input unit 19B is an interface that inputs sensor values ​​detected by the discharge pressure sensor 31, discharge temperature sensor 32, suction pressure sensor 33, suction temperature sensor 34, refrigerant temperature sensor 35, and outdoor air temperature sensor 36. The first output unit 19C is an interface that outputs signals that control the outdoor unit fan 18, the outdoor unit expansion valve 14, and the four-way valve 12. The first input / output unit 19D is an interface that outputs a signal to control the inverter circuit 11A and also inputs a signal to detect the output of the inverter circuit 11A, for example, an actual measured current value which is the actual measured driving current value flowing through the inverter circuit 11A when the compressor 11 is operating.

[0025] <Indoor unit configuration> 2, the indoor unit 3 has an indoor heat exchanger 51, an indoor unit expansion valve 52, a shut-off valve 53, a shut-off valve 54, an indoor unit fan 55, a second control unit 50, and a remote control 70 (see FIG. 1). The indoor heat exchanger 51, the indoor unit expansion valve 52, the shut-off valve 53, and the shut-off valve 54 are connected to each other by refrigerant pipes 56, 57 described later, and constitute an indoor unit refrigerant circuit that forms part of the refrigerant circuit 6.

[0026] The indoor heat exchanger 51 is a heat exchanger that exchanges heat between the refrigerant and indoor air that is drawn into the indoor unit 3 from an air inlet (not shown) by the rotation of the indoor unit fan 55. One refrigerant inlet / outlet of the indoor heat exchanger 51 is connected to a shut-off valve 53 by a refrigerant pipe 56. The other refrigerant inlet / outlet of the indoor heat exchanger 51 is connected to a shut-off valve 54 by a refrigerant pipe 57. The indoor heat exchanger 51 functions as a condenser when the air conditioner 1 is performing heating operation. On the other hand, the indoor heat exchanger 51 functions as an evaporator when the air conditioner 1 is performing cooling operation.

[0027] The indoor unit expansion valve 52 is an electronic expansion valve provided in the refrigerant piping 56. When the indoor heat exchanger 51 functions as an evaporator, i.e., when the indoor unit 3 performs cooling operation, the opening degree of the indoor unit expansion valve 52 is adjusted so that the refrigerant superheat degree at the refrigerant outlet (shut-off valve 54 side) of the indoor heat exchanger 51 becomes a target refrigerant superheat degree. Also, when the indoor heat exchanger 51 functions as a condenser, i.e., when the indoor unit 3 performs heating operation, the opening degree of the indoor unit expansion valve 52 is adjusted so that the refrigerant subcooling degree at the refrigerant outlet (shut-off valve 53 side) of the indoor heat exchanger 51 becomes a target refrigerant subcooling degree. Here, the target refrigerant superheat degree and the target refrigerant subcooling degree are the refrigerant superheat degree and the refrigerant subcooling degree required for the indoor unit 3 to exhibit sufficient cooling or heating capacity.

[0028] The indoor unit fan 55 is made of a resin material and is disposed near the indoor heat exchanger 51. The indoor unit fan 55 is rotated by a fan motor (not shown) to draw indoor air into the indoor unit 3 from an air inlet (not shown) and generate an air flow for discharging the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 51 into the room from an air outlet (not shown).

[0029] Various sensors are provided in the indoor unit 3. A liquid-side refrigerant temperature sensor 61 is arranged in the refrigerant piping 56, between the indoor heat exchanger 51 and the indoor unit expansion valve 52, to detect the temperature of the refrigerant flowing into the indoor heat exchanger 51 or the temperature of the refrigerant flowing out from the indoor heat exchanger 51. A gas-side refrigerant temperature sensor 62 is arranged in the refrigerant piping 57 to detect the temperature of the refrigerant flowing out from or into the indoor heat exchanger 51. A suction temperature sensor 63 is arranged near an air inlet (not shown) of the indoor unit 3 to detect the temperature of the indoor air flowing into the indoor unit 3, i.e., the suction temperature.

[0030] The second control unit 50 controls the entire indoor unit 3. As shown in FIG. 1 , the second control unit 50 has a second communication unit 50A, a third communication unit 50B, a second input unit 50C, and a second output unit 50D. The second communication unit 50A is an interface such as UART that communicates with the first control unit 19 in the outdoor unit 2 or with the centralized controller 7 via the communication network 8. The third communication unit 50B communicates with the remote control 70 via remote communication such as infrared communication. The second input unit 50C is an interface that inputs sensor values ​​detected by the liquid-side refrigerant temperature sensor 61, the gas-side refrigerant temperature sensor 62, and the suction temperature sensor 63. The second output unit 50D is an interface that outputs signals that control the indoor unit fan 55 and the indoor unit expansion valve 52.

[0031] <Operation of the refrigerant circuit> Next, the flow of refrigerant in the refrigerant circuit 6 and the operation of each part during air conditioning operation of the air conditioner 1 in this embodiment will be described.

[0032] When the air conditioner 1 performs heating operation, the four-way valve 12 is switched so that the first port 12A and the fourth port 12D are connected and the second port 12B and the third port 12C are connected. As a result, the refrigerant circuit 6 becomes a heating cycle in which each indoor heat exchanger 51 functions as a condenser and the outdoor heat exchanger 13 functions as an evaporator. For ease of explanation, the flow of refrigerant during heating operation is indicated by solid arrows in Figure 2.

[0033] When the compressor 11 is driven with the refrigerant circuit 6 in the above state, the refrigerant discharged from the compressor 11 flows through the refrigerant piping 21 and into the four-way valve 12, then flows from the four-way valve 12 through the refrigerant piping 24 and into the gas pipe 5 via the second shut-off valve 16. The refrigerant flowing through the gas pipe 5 is diverted to each indoor unit 3 via each shut-off valve 54. The refrigerant that has flowed into each indoor unit 3 flows through each refrigerant piping 57 and into each indoor heat exchanger 51. The refrigerant that has flowed into each indoor heat exchanger 51 condenses by exchanging heat with indoor air drawn into each indoor unit 3 by the rotation of each indoor unit fan 55. In other words, each indoor heat exchanger 51 functions as a condenser, and the indoor air heated by the refrigerant in each indoor heat exchanger 51 is blown into the room from an air outlet (not shown), thereby heating the room in which each indoor unit 3 is installed.

[0034] The refrigerant that flows from each indoor heat exchanger 51 into each refrigerant pipe 56 is decompressed by passing through each indoor unit expansion valve 52, the opening of which is adjusted so that the degree of refrigerant subcooling at the refrigerant outlet side of each indoor heat exchanger 51 becomes the target degree of refrigerant subcooling. Here, the target degree of refrigerant subcooling is determined based on the cooling capacity required by each indoor unit 3.

[0035] The refrigerant decompressed by each indoor unit expansion valve 52 flows from each refrigerant pipe 56 through each shut-off valve 53 into the liquid pipe 4. The refrigerant that joins in the liquid pipe 4 flows into the outdoor unit 2 through the first shut-off valve 15. The refrigerant that flows into the first shut-off valve 15 of the outdoor unit 2 flows through the refrigerant pipe 25 and is decompressed while passing through the outdoor unit expansion valve 14. The refrigerant that is decompressed by the outdoor unit expansion valve 14 flows through the refrigerant pipe 25 into the outdoor heat exchanger 13, and evaporates through heat exchange with outside air that flows in from an intake port (not shown) of the outdoor unit 2 due to the rotation of the outdoor unit fan 18. The refrigerant that flows out from the outdoor heat exchanger 13 into the refrigerant pipe 26 flows in this order: the four-way valve 12, the refrigerant pipe 26, the accumulator 17, and the refrigerant pipe 22. The refrigerant that has flowed in is then sucked into the compressor 11 and compressed again, and flows out into the refrigerant pipe 24 via the first port 12A and the fourth port 12D of the four-way valve 12.

[0036] Furthermore, when the air conditioner 1 performs cooling operation, the four-way valve 12 is switched so that the first port 12A and the second port 12B are connected, and the third port 12C and the fourth port 12D are connected. As a result, the refrigerant circuit 6 becomes a cooling cycle in which each indoor heat exchanger 51 functions as an evaporator and the outdoor heat exchanger 13 functions as a condenser. For ease of explanation, the flow of refrigerant during cooling operation is indicated by dashed arrows in Figure 2.

[0037] When the compressor 11 is driven in the state of the refrigerant circuit 6, the refrigerant discharged from the compressor 11 flows through the refrigerant piping 21 and into the four-way valve 12, then flows from the four-way valve 12 through the refrigerant piping 26 and into the outdoor heat exchanger 13. The refrigerant that has flowed into the outdoor heat exchanger 13 condenses by exchanging heat with outdoor air that has been drawn into the outdoor unit 2 by the rotation of the outdoor unit fan 18. In other words, the outdoor heat exchanger 13 functions as a condenser, and the indoor air heated by the refrigerant in the outdoor heat exchanger 13 is blown out to the outside through an air outlet (not shown).

[0038] The refrigerant that flows from the outdoor heat exchanger 13 into the refrigerant piping 25 passes through the outdoor unit expansion valve 14, which is fully open, and is decompressed. The refrigerant decompressed by the outdoor unit expansion valve 14 flows through the liquid pipe 4 via the first shut-off valve 15 and is diverted to each indoor unit 3. The refrigerant that flows into each indoor unit 3 flows through the refrigerant piping 56 via each shut-off valve 53 and is decompressed by passing through the indoor unit expansion valve 52, which has been adjusted to an opening such that the refrigerant subcooling degree becomes the target refrigerant subcooling degree at the refrigerant outlet of the indoor heat exchanger 51. The refrigerant decompressed by the indoor unit expansion valve 52 flows through the refrigerant piping 56 and flows into the indoor heat exchanger 51, where it exchanges heat with indoor air that flows in from an intake port (not shown) of the indoor unit 3 as the indoor unit fan 55 rotates, and evaporates. In other words, each indoor heat exchanger 51 functions as an evaporator, and the indoor air cooled by the refrigerant in each indoor heat exchanger 51 is blown into the room from an air outlet (not shown), thereby cooling the room in which each indoor unit 3 is installed.

[0039] The refrigerant flowing from the indoor heat exchanger 51 to the gas pipe 5 via the shut-off valve 54 flows into the refrigerant piping 24 via the second shut-off valve 16 of the outdoor unit 2 and flows into the fourth port 12D of the four-way valve 12. The refrigerant that has flowed into the fourth port 12D of the four-way valve 12 flows from the third port 12C into the refrigerant inlet side of the accumulator 17. The refrigerant that has flowed into the refrigerant inlet side of the accumulator 17 flows through the refrigerant piping 22, is sucked into the compressor 11, and is compressed again.

[0040] 3 is a Mollier diagram showing the refrigeration cycle of the air conditioner 1. During cooling operation of the air conditioner 1, the outdoor heat exchanger 13 functions as a condenser, and the indoor heat exchanger 51 functions as an evaporator. During heating operation of the air conditioner 1, the outdoor heat exchanger 13 functions as an evaporator, and the indoor heat exchanger 51 functions as a condenser.

[0041] The compressor 11 compresses the low-temperature, low-pressure gas refrigerant flowing in from the evaporator and discharges the high-temperature, high-pressure gas refrigerant (the refrigerant in the state of point B in FIG. 3). The temperature of the gas refrigerant discharged from the compressor 11 is the discharge temperature, which is detected by the discharge temperature sensor 32.

[0042] The condenser condenses the high-temperature, high-pressure gas refrigerant from the compressor 11 by heat exchange with air. After the gas refrigerant changes to liquid due to latent heat change, the temperature of the liquid refrigerant drops due to sensible heat change, resulting in a supercooled state (point C in Figure 3). The temperature at which the gas refrigerant changes to liquid due to latent heat change is the high-pressure saturation temperature, and the temperature of the supercooled refrigerant at the condenser outlet is the heat exchanger outlet temperature. The high-pressure saturation temperature is calculated using the discharge pressure value (pressure value P2, labeled "HPS" in Figure 3) detected by the discharge pressure sensor 31. The heat exchanger outlet temperature is detected by the refrigerant temperature sensor 35. Using a Mollier diagram, the discharge specific enthalpy can be calculated based on the discharge pressure value and discharge temperature. For ease of explanation, the air conditioner 1 is illustrated as being equipped with a discharge temperature sensor 32 that detects the discharge temperature. However, even if the discharge temperature cannot be detected, the discharge specific enthalpy can be calculated based on the discharge pressure value P2 and the discharge superheat. However, in this case, the discharge superheat degree is an estimated value obtained by conducting tests in advance, and if the state of the refrigerant circuit 6 differs between when the test was conducted and when it is actually in operation, the calculation accuracy of the discharge specific enthalpy may be reduced compared to when the actually measured discharge temperature is used. For this reason, it is desirable to install a discharge temperature sensor 32 and obtain the discharge superheat degree using the actually measured discharge temperature.

[0043] The expansion valve reduces the pressure of the low-temperature, high-pressure refrigerant that has flowed out of the condenser, turning it into a two-phase gas-liquid refrigerant in which gas and liquid are mixed (the refrigerant in the state of point D in FIG. 3).

[0044] The evaporator evaporates the two-phase gas-liquid refrigerant that has flowed in through heat exchange with air. After the two-phase gas-liquid refrigerant is completely converted into gas refrigerant through latent heat change in the evaporator, the temperature of the gas refrigerant rises through sensible heat change, becoming superheated (the state indicated by point A in FIG. 3), and is then drawn into the compressor 11. The temperature at which the liquid refrigerant is undergoing a phase change into gas refrigerant through latent heat change is the low-pressure saturation temperature. The low-pressure saturation temperature is determined using the suction pressure value (pressure value P1 indicated as "LPS" in FIG. 3) detected by the suction pressure sensor 33. The temperature of the refrigerant that has been superheated in the evaporator and drawn into the compressor 11 is the suction temperature. The suction temperature is detected by the suction temperature sensor 34. Using a Mollier diagram, the suction specific enthalpy can be calculated based on the suction pressure value and the suction temperature. For ease of explanation, the air conditioner 1 is shown equipped with an intake temperature sensor 34 that detects intake temperature. However, even if the intake temperature cannot be detected, the intake specific enthalpy can be calculated based on the intake pressure value P1 and the intake superheat. However, the intake superheat in this case is an estimated value obtained by conducting a test or the like in advance. If the state of the refrigerant circuit 6 differs between the test and actual operation, the accuracy of calculating the intake specific enthalpy may be reduced compared to when the actually measured intake temperature is used. For this reason, it is desirable to install an intake temperature sensor 34 and calculate the intake superheat using the actually measured intake temperature.

[0045] The degree of refrigerant subcooling when the refrigerant is in a subcooled state when it flows out of the condenser can be calculated by subtracting the refrigerant temperature at the refrigerant outlet of the heat exchanger functioning as a condenser (the heat exchange outlet temperature) from the high-pressure saturation temperature. The degree of refrigerant superheat when the refrigerant is in a superheated state when it flows out of the evaporator can be calculated by subtracting the suction temperature from the low-pressure saturation temperature.

[0046] <Configuration of the centralized controller> FIG. 4 is a block diagram showing an example of the centralized controller 7 according to the first embodiment. The centralized controller 7 shown in FIG. 4 includes a first communication unit 71, a second communication unit 72, a storage unit 73, and a control unit 74. The first communication unit 71 is an interface such as UART that communicates with the server device 110 via the communication network 120. The second communication unit 72 is an interface such as UART that communicates with the first control unit 19 in the outdoor unit 2 or the second control unit 50 in the indoor unit 3 via the communication network 8. The storage unit 73 is, for example, a flash memory, and stores various types of information, programs, and the like. The storage unit 73 stores a learning model 73A generated by the server device 110.

[0047] The control unit 74 functions as a failure estimation device that estimates a failure of the compressor 11. The control unit 74 has a detection unit 741, an acquisition unit 742, a calculation unit 743, an estimation unit 744, and a determination unit 745. The detection unit 741 acquires, from the first control unit 19 of the outdoor unit 2, for example, a measured current value, which is the value of a current flowing through the primary side of the inverter circuit 11A when the compressor 11 is driven. Furthermore, the acquisition unit 742 acquires, in addition to the above-mentioned measured current value, characteristic quantities related to the driving of the compressor 11, which will be described below. The characteristic quantities related to the driving of the compressor 11 that are acquired include the rotation speed of the compressor 11, state quantities of the refrigerant related to the driving of the compressor 11, and state quantities (coefficients) related to the efficiency of the compressor 11. The state quantities of the refrigerant related to the operation of the compressor 11 are the sensor values ​​of the discharge pressure sensor 31, discharge temperature sensor 32, suction pressure sensor 33, suction temperature sensor 34, refrigerant temperature sensor 35, and outdoor air temperature sensor 36 in the outdoor unit 2 from the first control unit 19. Furthermore, the acquisition unit 742 acquires the sensor values ​​of the liquid side refrigerant temperature sensor 61, gas side refrigerant temperature sensor 62, and suction temperature sensor 63 from the second control unit 50 of each indoor unit 3 as the state quantities of the refrigerant related to the operation of the compressor 11.

[0048] Furthermore, the acquisition unit 742 acquires a state quantity (coefficient) related to the efficiency of the compressor 11 from the learning model 73A. The learning model 73A estimates the state quantity (coefficient) related to the efficiency of the compressor 11 using the rotation speed of the compressor 11 and a state quantity of the refrigerant related to the driving of the compressor 11. The estimation of the state quantity (coefficient) related to the efficiency of the compressor 11 will be described in detail later.

[0049] That is, the acquisition unit 742 periodically acquires the measured current value, the rotation speed of the compressor 11, the state quantity of the refrigerant related to the operation of the compressor 11, and the state quantity (coefficient) related to the efficiency of the compressor 11.

[0050] The calculation unit 743 calculates a refrigerant suction density, which is the density of the refrigerant sucked into the compressor 11, using the acquired state quantities of the refrigerant related to the operation of the compressor 11. Specifically, the calculation unit 743 refers to a table in which the refrigerant suction density is associated with the suction pressure value and suction temperature of the compressor 11, and acquires the refrigerant suction density corresponding to the suction pressure value and the suction temperature. The table is obtained in advance by performing tests or the like, and is stored in the storage unit 73 of the centralized controller 7 (not shown in FIG. 4).

[0051] The calculation unit 743 calculates a specific enthalpy difference, which is the difference between the discharge specific enthalpy, which is the specific enthalpy of the refrigerant discharged from the compressor 11, and the suction specific enthalpy, which is the specific enthalpy of the refrigerant drawn into the compressor 11. Specifically, the calculation unit 743 calculates the specific enthalpy difference by subtracting the suction specific enthalpy from the discharge specific enthalpy. The calculation unit 743 calculates the discharge specific enthalpy based on the Mollier diagram shown in FIG. 3, the discharge pressure value, and the discharge temperature. Furthermore, the calculation unit 743 calculates the suction specific enthalpy based on the Mollier diagram shown in FIG. 3, the suction pressure value, and the suction temperature. The Mollier diagram shown in FIG. 3 is calculated in advance by performing a test or the like and is stored in the memory unit 73 of the centralized controller 7 (not shown in FIG. 4). The memory unit 73 stores, for example, the discharge pressure value, the discharge temperature, the suction pressure value, the suction temperature, the suction specific enthalpy, the discharge specific enthalpy, and the like in the Mollier diagram shown in FIG. 3.

[0052] The estimation unit 744 uses the feature quantity to estimate an estimated current value as a drive current value according to the operating load of the compressor 11. The estimation unit 744 estimates the estimated current value using the refrigerant suction density (referred to as p in the following formula), the rotation speed of the compressor 11, the specific enthalpy difference, and a state quantity (coefficient, referred to as k in the following formula) related to the efficiency of the compressor 11.

[0053] Formula: Estimated current value = k × p × (rotational speed of compressor 11) × specific enthalpy difference

[0054] The estimation unit 744 estimates the estimated current value every time the acquisition unit 742 acquires the rotation speed of the compressor 11 and the state quantity of the refrigerant related to the driving of the compressor 11 (for example, every 5 minutes).

[0055] The determination unit 745 determines whether or not the compressor 11 is faulty based on the comparison result between the estimated current value estimated by the estimation unit 744 and the actual measured current value detected by the detection unit 741. The determination unit 745 determines that the compressor 11 is not faulty if the ratio between the estimated current value and the actual measured current value, for example, (actual measured current value / estimated current value), is within a predetermined range. The ratio is the ratio between the estimated current value and the actual measured current value. Furthermore, the determination unit 745 determines that the compressor 11 is faulty if the ratio between the estimated current value and the actual measured current value is outside the predetermined range.

[0056] FIG. 5 shows an example of a normal distribution of ratios, and a malfunction of the compressor 11 is determined based on whether the ratio falls within a predetermined range in the normal distribution. Here, the predetermined range is, for example, μ±2σ, as shown in FIG. 5, where σ is the standard deviation of the occurrence of the statistically calculated ratios and μ is the mean value of the occurrence of the ratios. In the predetermined range μ±2σ, the ratio falls within a range of 0.6 to 1.4. Approximately 95% of the calculated ratios fall within the μ±2σ range. Meanwhile, the remaining approximately 5% of the calculated ratios fall outside the μ±2σ range. A situation in which the calculated ratio frequently falls outside the predetermined range is unlikely to occur when the compressor 11 is operating normally, and it can be assumed that an abnormality has occurred in the compressor 11, i.e., that the compressor 11 is malfunctioning.

[0057] In this embodiment, when the calculated ratio frequently falls outside the predetermined range and the actual measurement average value μ falls outside the range of ±2σ, the compressor 11 is determined to be faulty. Note that the smaller the value of the predetermined range, the higher the sensitivity for determining that the compressor 11 is faulty, but the greater the possibility of erroneously determining that a compressor 11 is not faulty. Therefore, in this embodiment, the range of ±2σ is used, which provides a good balance between sensitivity and accuracy in fault determination. However, if higher sensitivity is desired, the predetermined range can be set to ±1σ, and if higher accuracy is desired, the predetermined range can be set to ±3σ.

[0058] The determination unit 745 sequentially calculates the ratio between the estimated current value and the actually measured current value (each time it acquires the rotation speed of the compressor 11 or a state quantity of the refrigerant related to the operation of the compressor 11), calculates the average value of the ratio for a predetermined period of time, for example, for one hour, and determines whether the calculated average value of the ratio is within a predetermined range. If the average value of the ratio is within the predetermined range, the determination unit 745 determines that the compressor 11 is not malfunctioning, i.e., is normal. If the average value of the ratio is outside the predetermined range, the determination unit 745 determines that the compressor 11 is malfunctioning.

[0059] <Server device configuration> As shown in FIG. 1 , the server device 110 includes a storage unit 111 and a learning unit 112. The storage unit 111 periodically collects, for example, the rotation speed, discharge pressure, and suction pressure of the compressor 11 as feature quantities from the centralized controller 7, for example, every five minutes, and stores the collected feature quantities. The learning unit 112 generates a learning model 73A for calculating a state quantity (coefficient) k related to the efficiency of the compressor 11 using feature quantities stored in the storage unit 111 for a certain period, for example, 30 days. Thereafter, the learning model is updated every 30 days using the feature quantities acquired up to that point. The learning unit 112 provides the generated or updated learning model 73A to the centralized controller 7. The centralized controller 7 stores the learning model 73A received from the server device 110 in the memory unit 73.

[0060] <Learning model> As described above, the state quantity (coefficient) k related to the efficiency of the compressor 11 can be calculated using the learning model 73A. The state quantity (coefficient) k related to the efficiency of the compressor 11 will now be described. The state quantity (coefficient) k related to the efficiency of the compressor 11 can be calculated, for example, using the volumetric efficiency, compression efficiency, and swept volume (displacement volume) of the compressor 11. However, the volumetric efficiency and compression efficiency of the compressor 11 vary depending on the rotation speed of the compressor 11 and the pressure ratio (ratio of high pressure to low pressure) in the refrigerant circuit 6. Furthermore, for example, the delivery note and specifications for the compressor 11 only list values ​​under limited operating conditions. Since there is no data for all conceivable conditions, it is difficult to store the values ​​in advance, for example, as a table in a memory unit. Furthermore, while the swept volume of the compressor 11 can be obtained for compressors manufactured in-house, it is often difficult to obtain the value when purchasing a compressor from another company because it is often not listed on the delivery note or specifications. Furthermore, in the case of an existing air conditioner, there may be cases where the information and specifications of the compressor installed are unknown. Therefore, it is difficult to determine the state quantity (coefficient) k related to the efficiency of the compressor 11 from the volumetric efficiency, compression efficiency, and stroke volume of the compressor 11. Therefore, in this embodiment, the state quantity (coefficient) k related to the efficiency of the compressor 11 is determined using the learning model 73A based on the rotation speed, discharge pressure value, and suction pressure value of the compressor 11.

[0061] The learning model 73A is generated by multiple regression analysis, a type of regression analysis, using the rotation speed, discharge pressure, and suction pressure of the compressor 11 from among multiple feature quantities. In multiple regression analysis, the regression equation obtained from multiple simulation results is selected to have the smallest P value (a value (predetermined weight parameter) indicating the degree of influence that the operating state quantity has on the accuracy of the generated learning model) and the largest possible corrected R2 (a value indicating the accuracy of the generated learning model) between 0.9 and 1.0, inclusive, and is generated as the learning model. Here, the P value and corrected R2 are values ​​related to the accuracy of the learning model when generating the learning model using multiple regression analysis; the smaller the P value and the closer the corrected R2 is to 1.0, the higher the accuracy of the generated learning model.

[0062] The learning model 73A is a regression equation for determining a state quantity (coefficient) k related to the efficiency of the compressor 11. The regression equation is, for example, (α1 × rotation speed of the compressor 11) + (α2 × discharge pressure value) + (α3 × suction pressure value) + α4. The coefficients α1 to α4 are determined when determining the state quantity (coefficient) k related to the efficiency of the compressor 11. The control unit 74 calculates the state quantity (coefficient) k related to the efficiency of the compressor 11 at the current time by substituting the current rotation speed, discharge pressure value, and suction pressure value of the compressor 11 acquired by the acquisition unit 742 into the regression equation.

[0063] <Learning process> Here, the learning process performed by the learning unit 112 when generating the learning model 73A will be described. Fig. 6 is a flowchart showing an example of the processing operation of the learning unit 112 related to the learning process of the first embodiment. In Fig. 6, the learning unit 112 in the server device 110 periodically (for example, every 5 minutes) acquires the rotation speed, discharge pressure value, and suction pressure value of the compressor 11 from the centralized controller 7 (step S11). Then, the learning unit 112 sequentially accumulates the acquired rotation speed, discharge pressure value, and suction pressure value of the compressor 11 in the accumulation unit 111.

[0064] The learning unit 112 generates a learning model 73A using the rotation speed, discharge pressure value, and suction pressure value of the compressor 11 for a certain period, for example, 30 days, acquired in step S11 (step S12). The learning unit 112 transmits the generated learning model 73A to the centralized controller 7 via the communication network 120 (step S13), and ends the processing operation shown in Fig. 6. Then, the centralized controller 7 stores the learning model 73A received via the communication network 120 in the memory unit 73.

[0065] <Fault detection process> Next, a failure determination process that enables the centralized controller 7 to constantly determine whether or not there is a failure in the compressor 11 will be described. FIG. 7 is a flowchart showing an example of the processing operation of the centralized controller 7 related to the failure determination process of the first embodiment. In FIG. 7, the control unit 74 in the centralized controller 7 determines whether or not it is currently an acquisition timing (step S21). The acquisition timing is every five minutes as described above. If it is currently an acquisition timing (step S21: Yes), the acquisition unit 742 in the control unit 74 acquires the rotation speed, discharge pressure value, suction pressure value, and actual measured current value of the compressor 11 (step S22). The discharge pressure value is detected by the discharge pressure sensor 31, and the suction pressure value is detected by the suction pressure sensor 33. The actual measured current value is detected by the detection unit 741 from the inverter circuit 11A of the compressor 11.

[0066] The calculation unit 743 in the control unit 74 uses the learning model 73A to calculate the state quantity (coefficient) k related to the efficiency of the compressor 11 (step S23). The learning model 73A calculates the state quantity (coefficient) k related to the efficiency of the compressor 11 by substituting the rotation speed, discharge pressure value, and suction pressure value of the compressor 11 into a regression equation.

[0067] The estimator 744 in the controller 74 estimates the estimated current value of the compressor 11 using the calculated state variable (coefficient) k related to compressor efficiency, the refrigerant suction density of the compressor 11, the rotation speed of the compressor 11, the discharge specific enthalpy, and the suction specific enthalpy (step S24). Although not shown, a table correlating the suction pressure value and suction temperature of the compressor 11 with the refrigerant suction density is pre-stored in the memory 73. The calculator 743 references this table to obtain the refrigerant suction density corresponding to the suction pressure value and the suction temperature. The calculator 743 calculates the discharge specific enthalpy based on the Mollier diagram shown in FIG. 3, the discharge pressure value, and the discharge temperature. Furthermore, the calculator 743 calculates the suction specific enthalpy based on the Mollier diagram shown in FIG. 3, the suction pressure value, and the suction temperature. Then, the estimation unit 744 estimates the estimated current value of the compressor 11 using (state quantity (coefficient) k related to efficiency) × (refrigerant suction density p) × (rotation speed of the compressor 11) × (discharge specific enthalpy - suction specific enthalpy).

[0068] The determination unit 745 in the control unit 74 performs an operation of dividing the actually measured current value by the estimated current value to calculate the current ratio (step S25). The determination unit 745 determines whether or not the ratio for a predetermined time period has been calculated (step S26). The predetermined time period is, for example, one hour. If the determination unit 745 has not calculated the ratio for the predetermined time period (step S26: No), the process returns to step S21. If the determination unit 745 has calculated the ratio for the predetermined time period (step S26: Yes), the determination unit 745 calculates an average ratio from the ratio for the predetermined time period (step S27).

[0069] The determination unit 745 then determines whether the calculated average value of the ratio is outside a predetermined range (step S29). If the calculated average value of the ratio is outside the predetermined range (step S29: Yes), the determination unit 745 determines that the compressor 11 has failed (step S30), outputs a notification of the compressor 11 failure (step S31), and ends the processing operation shown in Fig. 7. The notification output is an alarm output that notifies the user of the failure of the compressor 11 on the display of a remote control that operates the air conditioner 1, or on the display of a PC or mobile terminal of an administrator that manages the air conditioner 1. As a result, the air conditioner 1 can determine the state of the compressor 11 and infer a failure even during normal operation, without requiring any special operation or device.

[0070] If the calculated average value of the ratio is within a predetermined range (step S29: No), the determination unit 745 determines that the compressor 11 is normal (step S32), and ends the processing operation shown in Fig. 7. If the current time is not the acquisition timing (step S21: No), the control unit 74 returns to the processing of step S21 to determine whether the current time is the acquisition timing.

[0071] <Effects of Example 1> In the air conditioner 1 of Example 1, a malfunction of the compressor 11 can be determined using only feature quantities that can be detected in a normal air conditioner, so no special operation is required for the determination, and no special device is required. Moreover, the air conditioner 1 always determines whether or not there is a malfunction of the compressor 11 using the actual measured current value and estimated current value of the compressor 11, so that a malfunction of the compressor 11 can always be accurately determined. As a result, a malfunction of the compressor 11 can always be accurately determined, simply, and at low cost.

[0072] Conventional air conditioners have detected a malfunction of the compressor 11 by detecting an abnormal current with a single threshold value (for example, 50 A or more). For example, under high load (high rotation) operation, a malfunction of the compressor 11 can be detected and stopped with a single threshold value, but under low load (low rotation) operation, a malfunction of the compressor 11 cannot be detected and stopped for the following reasons.

[0073] For example, even if a load of approximately 20 A under normal conditions drops to 30 A due to deterioration of the compressor 11, the measured current is below the threshold and therefore cannot be detected as a malfunction of the compressor 11. Furthermore, if the compressor 11 continues to operate with the measured current at 30 A, for example, the shaft of the motor housed inside the compressor 11 may be damaged, causing minute powdery fragments (iron powder) from a chipped portion of the shaft to be ejected into the refrigerant circuit 6 along with the refrigerant and circulate within the refrigerant circuit 6, potentially damaging the devices and components that make up the refrigerant circuit 6, such as by getting caught in the valve portion of the expansion valve. In this case, replacing the compressor 11 does not remove the powdery fragments remaining in the refrigerant circuit 6, and damage caused by these powdery fragments may occur. The air conditioner 1 of the first embodiment can detect abnormalities in the compressor 11 early, allowing the compressor 11 to be replaced before a large amount of the powdery fragments enters the refrigerant circuit 6, thereby preventing damage to the devices and components that make up the refrigerant circuit 6.

[0074] In the air conditioning system 100 of Example 1, a case has been exemplified in which a learning model 73A learned by the learning unit 112 in the server device 110 is generated, and the generated learning model 73A is provided to the centralized controller 7. However, a generation unit that generates a learning model may be provided in the centralized controller 7, and an embodiment of this will be described below as Example 2. [Example]

[0075] Fig. 8 is a block diagram showing an example of an air conditioning system 100A of Example 2. Note that the same components of the air conditioning system 100 of Example 1 and the air conditioning system 100A of Example 2 are assigned the same reference numerals, and descriptions of the overlapping components and operations will be omitted. The air conditioning system 100A shown in Fig. 8 does not include a server device 110, and is composed of an air conditioner 1 including an outdoor unit 2, an indoor unit 3, and a central controller 7A. The air conditioner 1 shown in Fig. 8 is an air conditioner that cannot communicate with the server device 110.

[0076] Fig. 9 is a block diagram illustrating an example of a centralized controller 7A according to Example 2. The control unit 74 in the centralized controller 7A illustrated in Fig. 9 includes a detection unit 741, an acquisition unit 742, a calculation unit 743, an estimation unit 744, and a determination unit 745, as well as a generation unit 746 that generates a learning model 73A that determines a state quantity (coefficient) k related to the efficiency of the compressor 11.

[0077] The generation unit 746 periodically collects, for example, the rotation speed, discharge pressure value, and suction pressure value of the compressor 11 as feature quantities, for example, every five minutes, and stores the collected feature quantities. The generation unit 746 uses the accumulated rotation speed, discharge pressure value, and suction pressure value of the compressor 11 for a certain period, for example, 30 days, to generate a learning model 73A that calculates a state quantity (coefficient) k related to the efficiency of the compressor 11. The generation unit 746 stores the generated learning model 73A in the storage unit 73.

[0078] <Effects of Example 2> Even in an air conditioner 1 that cannot communicate with the server device 110 of Example 2, a malfunction of the compressor 11 can be determined using only feature values ​​that can be detected by a normal air conditioner, so no special operation is required for the determination, and no special device is required. Moreover, the air conditioner 1 always determines whether or not there is a malfunction of the compressor 11 using the actual measured current value and estimated current value of the compressor 11, so that a malfunction of the compressor 11 can always be accurately determined. As a result, a malfunction of the compressor 11 can always be accurately determined, simply, and at low cost.

[0079] <Modification> In the first and second embodiments described above, the discharge specific enthalpy is calculated using the discharge pressure and the discharge temperature. However, there may be cases where the discharge temperature cannot be detected in an air conditioner. Therefore, the following describes a case where the discharge enthalpy can be calculated from the discharge pressure even if the discharge temperature cannot be detected.

[0080] As described above, in each embodiment, the air conditioner 1 is equipped with a discharge temperature sensor 32. However, there are cases where the discharge temperature sensor 32 is not equipped. In this case, even if the air conditioner 1 is not equipped with a discharge temperature sensor 32, the discharge specific enthalpy can be calculated using the discharge pressure value as long as the discharge superheat degree is known, as shown in FIG. 3 . However, in this case, the discharge superheat degree is an estimated value obtained by conducting a test or the like in advance. If the state of the refrigerant circuit 6 differs between the test and actual operation, the calculation accuracy of the discharge specific enthalpy may be reduced compared to when the actual discharge temperature is used. Therefore, it goes without saying that the calculation accuracy of the discharge specific enthalpy is improved by installing a discharge temperature sensor 32 and calculating the discharge superheat degree using the actual discharge temperature.

[0081] In addition, in the first and second embodiments, the case where the suction specific enthalpy is calculated using the suction pressure and the suction temperature is described. However, there may be cases where the suction temperature cannot be detected in the air conditioner. Therefore, for example, a case where the suction enthalpy can be calculated from the suction pressure even if the suction temperature cannot be detected will be described below.

[0082] As described above, in each embodiment, the air conditioner 1 is provided with an intake temperature sensor 34. However, there are cases where the intake temperature sensor 34 is not provided. In this case, even if the air conditioner 1 is not provided with an intake temperature sensor 34, the intake specific enthalpy can be calculated using the intake pressure value as long as the intake superheat degree is known, as shown in FIG. 3 . However, in this case, the intake superheat degree is an estimated value obtained by conducting a test or the like in advance. If the state of the refrigerant circuit 6 differs between the test and actual operation, the accuracy of the intake specific enthalpy calculation may be reduced compared to when the actually measured intake temperature is used. Therefore, it goes without saying that the accuracy of the intake specific enthalpy calculation is improved when the intake temperature sensor 34 is provided and the actually measured intake temperature is used to calculate the intake superheat degree.

[0083] It is also possible that an air conditioner may be equipped with only one of the discharge temperature sensor 32 and the intake temperature sensor 34, but the estimated value of the discharge superheat degree is more likely to vary compared to the intake superheat degree. Therefore, if only one of them is to be obtained, it is preferable to install only the discharge temperature sensor 32 and obtain the discharge temperature.

[0084] In addition, the control unit 74 in the centralized controller 7A in the air conditioner 1 of the second embodiment has been exemplified as performing the function of the failure estimation device. However, it does not have to be the control unit 74 in the centralized controller 7A, and for example, the function of the failure estimation device may be performed in the first control unit 19 in the outdoor unit 2 or the second control unit 50 in the indoor unit 3, and this can be changed as appropriate.

[0085] Software that executes the functions of the failure estimation device may be installed in the centralized controller 7A of the air conditioner 1, and the functions of the failure estimation device may be executed by the control unit 74 in the centralized controller 7A, and this can be changed as appropriate. In this case, by installing software that executes the functions of the failure estimation device in an existing air conditioner 1 that does not have a learning unit, it is possible to easily install the mechanism required to determine deterioration of the compressor 11 even in an existing air conditioner 1.

[0086] In the air conditioners 1 of Examples 1 and 2, a failure estimation device is exemplified that estimates a failure in the compressor 11 when N indoor units 3 are connected to one outdoor unit 2. However, even in an air conditioner 1 in which one outdoor unit 2 and one indoor unit 3 are connected, a failure in the compressor 11 can be estimated using a method similar to that of Examples 1 and 2.

[0087] In this embodiment, the learning model 73A is generated by the server device 110 or the centralized controller 7A, but the user may calculate the learning model 73A from simulation results. In addition, in this embodiment, the learning model 73A is generated using multiple regression analysis, but the learning model 73A may be generated using machine learning techniques such as SVR (Support Vector Regression) and NN (Neural Network), which are capable of performing general regression analysis. In this case, instead of using the P value or corrected R2 used in multiple regression analysis, a general technique for selecting features to improve the accuracy of the learning model 73A (such as forward feature selection or backward feature elimination) may be used.

[0088] Furthermore, the components of each unit shown in the figure do not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each unit is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0089] Furthermore, the various processing functions performed by each device may be executed in whole or in part on a CPU (Central Processing Unit) (or a microcomputer such as an MPU (Micro Processing Unit) or MCU (Micro Controller Unit)). Needless to say, the various processing functions may be executed in whole or in part on a program analyzed and executed by a CPU (or a microcomputer such as an MPU or MCU), or on hardware using wired logic. [Explanation of symbols]

[0090] 1. Air conditioner 2 Outdoor unit 3 Indoor unit 7 Centralized Controller 11 Compressor 13 Outdoor heat exchanger 14 Outdoor unit expansion valve 31 Discharge pressure sensor 32 Discharge temperature sensor 33 Intake pressure sensor 34 Intake temperature sensor 73A Learning Model 74 Control Unit 741 Detector 742 Acquisition Department 743 Calculation Unit 744 Estimation Department 745 Judgment section 746 Generation part

Claims

1. a detection unit that detects an actual current value that is an actual drive current value that drives the compressor; an acquisition unit that acquires, as feature quantities related to the operation of the compressor, the measured current value, a rotation speed of the compressor, a state quantity of the refrigerant related to the operation of the compressor, and a state quantity related to the efficiency of the compressor calculated using the rotation speed of the compressor, a discharge pressure of the compressor, and a suction pressure of the compressor; a calculation unit that calculates, using the state quantities of the refrigerant related to the operation of the compressor acquired by the acquisition unit, a refrigerant suction density that is the density of the refrigerant suctioned into the compressor, and a specific enthalpy difference that is the difference between a discharge specific enthalpy that is the specific enthalpy of the refrigerant discharged from the compressor and a suction specific enthalpy that is the specific enthalpy of the refrigerant suctioned into the compressor; an estimation unit that estimates, as an estimated current value, a drive current value according to an operating load of the compressor using state quantities related to the refrigerant suction density, the rotation speed of the compressor, the specific enthalpy difference, and efficiency of the compressor; a determination unit that determines a state of the compressor using the estimated current value estimated by the estimation unit and the actual measured current value detected by the detection unit; A fault estimation device comprising:

2. The determination unit: determining whether or not the compressor has failed based on a comparison result between the estimated current value estimated by the estimation unit and the actual measured current value detected by the detection unit; 2. The fault estimation device according to claim 1.

3. 3. The fault estimation device according to claim 2, further comprising a learning model that determines a state quantity related to the efficiency of the compressor using a rotation speed of the compressor and a state quantity of the refrigerant related to the operation of the compressor.

4. The state quantity of the refrigerant related to the driving of the compressor is 4. The fault estimating device according to claim 3, wherein the pressure includes a discharge pressure and a suction pressure of the compressor.

5. The state quantity of the refrigerant related to the driving of the compressor is The fault estimating device according to claim 4, further comprising a discharge temperature of the compressor.

6. The state quantity of the refrigerant related to the driving of the compressor is The fault estimating device according to claim 5, further comprising a suction temperature of the compressor.

7. 7. The failure estimation device according to claim 1, wherein the compressor is determined not to have a failure when the ratio between the estimated current value and the actual measured current value is within a predetermined range, and the compressor is determined to have a failure when the ratio between the estimated current value and the actual measured current value is outside the predetermined range.

8. The acquisition unit periodically acquiring the measured current value, the rotation speed of the compressor, and a state quantity of the refrigerant related to the operation of the compressor; The estimation unit the acquiring unit estimates the estimated current value each time it acquires a rotation speed of the compressor and a state quantity of the refrigerant related to the operation of the compressor; The determination unit 8. The fault estimation device according to claim 7, wherein a comparison result between the estimated current value and the actually measured current value is calculated each time the estimated current value is estimated, an average value of the comparison results for a predetermined period of time is calculated, and whether or not the compressor has a fault is determined based on the calculated average value.

9. A failure estimation device that estimates a compressor failure, A process of detecting an actual measured current value that is an actual measured drive current value that drives the compressor; a process of acquiring, as feature quantities related to the drive of the compressor, the measured current value, the rotation speed of the compressor, a state quantity of the refrigerant related to the drive of the compressor, and a state quantity related to the efficiency of the compressor calculated using the rotation speed of the compressor, the discharge pressure of the compressor, and the suction pressure of the compressor; a process of calculating a refrigerant suction density, which is the density of the refrigerant suctioned into the compressor, and a specific enthalpy difference, which is the difference between a discharge specific enthalpy, which is the specific enthalpy of the refrigerant discharged from the compressor, and a suction specific enthalpy, which is the specific enthalpy of the refrigerant suctioned into the compressor, using the acquired state quantities of the refrigerant related to the operation of the compressor; a process of estimating, as an estimated current value, a drive current value according to an operating load of the compressor using state quantities related to the refrigerant suction density, the rotation speed of the compressor, the specific enthalpy difference, and the efficiency of the compressor; a process of determining a state of the compressor using the estimated current value and the detected actual current value; A fault estimation method comprising:

10. an air conditioner having an outdoor unit equipped with a compressor, an outdoor heat exchanger, and an expansion valve, and an indoor unit connected to the outdoor unit; and a server device capable of communicating with the air conditioner; The server device a learning unit that generates a learning model for determining a state quantity related to the efficiency of the compressor using a rotation speed of the compressor and a state quantity of the refrigerant related to the operation of the compressor; The air conditioner comprises: a detection unit that detects an actual current value that is an actual drive current value that drives the compressor; an acquisition unit that acquires an actual measured current value of the compressor, a rotation speed of the compressor, a state quantity of the refrigerant related to the operation of the compressor, and a state quantity related to the efficiency of the compressor that is calculated using the rotation speed of the compressor, the discharge pressure of the compressor, and the suction pressure of the compressor; a calculation unit that calculates, using the state quantities of the refrigerant related to the operation of the compressor acquired by the acquisition unit, a refrigerant suction density that is the density of the refrigerant suctioned into the compressor, and a specific enthalpy difference that is the difference between a discharge specific enthalpy that is the specific enthalpy of the refrigerant discharged from the compressor and a suction specific enthalpy that is the specific enthalpy of the refrigerant suctioned into the compressor; an estimation unit that estimates a drive current value as an estimated current value in accordance with an operating load of the compressor using state quantities related to the refrigerant suction density, the rotation speed of the compressor, the specific enthalpy difference, and efficiency of the compressor; a determination unit that determines a state of the compressor using the estimated current value estimated by the estimation unit and the actual measured current value detected by the detection unit; An air conditioning system comprising:

11. An air conditioner having an outdoor unit equipped with a compressor, an outdoor heat exchanger, and an expansion valve, and an indoor unit connected to the outdoor unit, a detection unit that detects an actual current value that is an actual drive current value that drives the compressor; an acquisition unit that acquires an actual measured current value of the compressor, a rotation speed of the compressor, and a state quantity of the refrigerant related to the operation of the compressor; a learning model that is generated using the rotation speed of the compressor and a state quantity of the refrigerant related to the operation of the compressor acquired by the acquisition unit, and that calculates a state quantity related to the efficiency of the compressor that is calculated using the rotation speed of the compressor, a discharge pressure of the compressor, and a suction pressure of the compressor; a calculation unit that calculates, using the state quantities of the refrigerant related to the operation of the compressor acquired by the acquisition unit, a refrigerant suction density that is the density of the refrigerant suctioned into the compressor, and a specific enthalpy difference that is the difference between a discharge specific enthalpy that is the specific enthalpy of the refrigerant discharged from the compressor and a suction specific enthalpy that is the specific enthalpy of the refrigerant suctioned into the compressor; an estimation unit that estimates a drive current value as an estimated current value in accordance with an operating load of the compressor using state quantities related to the refrigerant suction density, the rotation speed of the compressor, the specific enthalpy difference, and efficiency of the compressor; a determination unit that determines a state of the compressor using the estimated current value estimated by the estimation unit and the actual measured current value detected by the detection unit; An air conditioner comprising:

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