Control device, refrigeration system, control method, and control program

Abstract

To properly perform processing for coping with a case where a compressor is in a predetermined state.SOLUTION: In a system comprising a compressor (50) having a motor (60) and a compressing mechanism (65), a control part (31) performs coping processing including at least one of output processing for outputting information indicating that the compressor (50) is in a predetermined state and change processing for changing operation conditions of the system if an index value indicative of a magnitude of a temporal change in a specific frequency component included in a physical quantity correlative with a state of the compressor (50) and a predetermined threshold have a predetermined relation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to control techniques. [Background technology]

[0002] Patent Document 1 discloses a fault symptom detection device for an air conditioner that includes a compressor including a motor and a drive unit that outputs a three-phase current to the motor. This fault symptom detection device includes a conversion unit and an abnormality detection unit. The conversion unit calculates the q-axis current of the motor from the measured value of the three-phase current and the rotation angle of the motor's rotor. The abnormality detection unit detects an abnormality in the compressor by comparing an evaluation value calculated by performing frequency analysis on the q-axis current with a reference value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6173530 Summary of the Invention [Problem to be solved by the invention]

[0004] In a compressor having a motor and a compression mechanism, there is a state in which a specific frequency component included in a physical quantity correlated with the state of the compressor changes suddenly. However, simply comparing the magnitude of the specific frequency component with a threshold value, as in Patent Document 1, may make it difficult to appropriately perform processing to deal with the case in which the compressor is in a predetermined state (a state in which the specific frequency component included in the physical quantity changes suddenly). [Means for solving the problem]

[0005] A first aspect of the present disclosure relates to a control device for controlling a system including a compressor (50) having a motor (60) and a compression mechanism (65). The control device includes a control unit (31) that performs countermeasure processing including at least one of an output processing for outputting information indicating that the compressor (50) is in a predetermined state and a change processing for changing an operating condition of the system when a relationship between an index value indicating a magnitude of a temporal change in a specific frequency component included in a physical quantity correlated with a state of the compressor (50) and a predetermined threshold value satisfies a predetermined relationship.

[0006] As a result of intensive research, the inventors of the present application have found that there exists a "state in which a specific frequency component contained in a physical quantity correlated with the state of the compressor (50) changes suddenly" in the state of the compressor (50) having a motor (60) and a compression mechanism (65). Furthermore, the inventors have found that such a state (the state of the compressor (50) in which the specific frequency component changes suddenly) can be estimated based on the magnitude of the temporal change in the specific frequency component contained in the physical quantity.

[0007] In the first aspect, a countermeasure is performed when a relationship between an index value indicating the magnitude of a change over time of a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and a predetermined threshold value satisfies a predetermined relationship, thereby making it possible to appropriately perform a countermeasure when the state of the compressor (50) is in a predetermined state (a state in which the specific frequency component changes suddenly).

[0008] A second aspect of the present disclosure is a control device according to the first aspect, wherein, under a condition where an amplitude value of the specific frequency component included in the physical quantity obtained within a 10-second period is derived every second, the index value is an absolute value of a difference between 1 and a value obtained by dividing a first moving average value (MA1) by a second moving average value (MA2), the first moving average value (MA1) is an average value of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at a time (ti) when the latest amplitude value is derived, the second moving average value (MA2) is an average value of 180 amplitude values ​​derived within a second period (T2) of 3 minutes ending at a time (ti) when the latest amplitude value is derived, and the threshold value is a value that is 1.1 times or more the maximum value of the index value obtained within a 10-minute measurement period under a condition where the compressor (50) is in a predetermined steady state, and the control unit (31) performs the corrective action when the index value exceeds the threshold.

[0009] As a result of extensive research, the inventors of the present application have found that by setting the threshold value for the index value to “a value that is 1.1 times or more the maximum index value obtained in a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state,” it is possible to estimate that the state of the compressor (50) is in a predetermined state (a state in which a specific frequency component changes suddenly) when the index value exceeds the threshold value.

[0010] In the second aspect, by taking action when the index value exceeds the threshold value, it is possible to appropriately take action to deal with the situation when the compressor (50) is in a predetermined state (a state in which a specific frequency component changes suddenly).

[0011] A third aspect of the present disclosure is a control device in which, in the control device of the first aspect, under conditions where an amplitude value of the specific frequency component included in the physical quantity obtained within a period of 10 seconds is derived every second, the index value is set to the absolute value of the difference between 1 and a value obtained by dividing a first moving average value (MA1) by a second moving average value (MA2), the first moving average value (MA1) is set to the average value of 10 of the amplitude values ​​derived within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value is derived, the second moving average value (MA2) is set to the average value of 180 of the amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value is derived, and the threshold value is set to 0.1, the control unit (31) is a control device that performs the countermeasure processing when the index value exceeds the threshold value.

[0012] As a result of extensive research, the inventors of the present application have found that by setting a threshold value for the index value to “0.1,” it is possible to estimate that the state of the compressor (50) is a predetermined state (a state in which a specific frequency component changes suddenly) when the index value exceeds the threshold value.

[0013] In the third aspect, by taking action when the index value exceeds the threshold value, it is possible to appropriately take action to deal with the situation when the compressor (50) is in a predetermined state (a state in which a specific frequency component changes suddenly).

[0014] A fourth aspect of the present disclosure is a control device according to any one of the first to third aspects, wherein the compression mechanism (65) has a compression chamber (68) for compressing a working fluid, the compression chamber (68) is sealed with lubricating oil, and the predetermined state is a state in which the sealing ability of the lubricating oil for the compression chamber (68) is broken.

[0015] As a result of extensive research, the inventors of the present application have discovered the following phenomenon: "When the sealing performance of the compression chamber (68) by the lubricating oil in the compressor (50) is broken, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) suddenly changes."

[0016] In the fourth aspect, it is possible to appropriately perform a process for dealing with the case where the compressor (50) is in a state where the sealing performance of the compression chamber (68) by the lubricating oil has been broken down.

[0017] A fifth aspect of the present disclosure is the control device according to any one of the first to third aspects, wherein the compression mechanism (65) has a compression chamber (68) for compressing a working fluid, the compressor (50) has an oil reservoir (54) for accumulating lubricating oil, and an oil supply path (100) for supplying the lubricating oil accumulated in the oil reservoir (54) to the compression chamber (68), and the oil supply path (100) has a suction port (101 a); The control device is configured such that the suction port (101a) is immersed in the lubricating oil accumulated in the oil reservoir (54), thereby enabling the lubricating oil sucked through the suction port (101a) to be supplied to the compression chamber (68), the compression chamber (68) is sealed by the lubricating oil, and the predetermined state is a state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).

[0018] As a result of extensive research, the inventors of the present application have discovered the following phenomenon: "When the suction port (101a) of the oil supply path (100) of the compressor (50) is no longer immersed in the lubricating oil accumulated in the oil reservoir (54), the sealing performance of the compression chamber (68) by the lubricating oil is broken down, and as a result, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) suddenly changes."

[0019] In the fifth aspect, appropriate processing can be performed to deal with the situation where the compressor (50) is in a state where the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).

[0020] A sixth aspect of the present disclosure is a control device according to any one of the first to third aspects, wherein the predetermined state is a liquid compression state in which a liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65).

[0021] As a result of extensive research, the inventors of the present application have discovered the following phenomenon: "When a liquid working fluid is sucked into the compression mechanism (65) in the compressor (50) and compressed in the compression mechanism (65), a specific frequency component included in a physical quantity correlated with the state of the compressor (50) suddenly changes."

[0022] In the sixth aspect, it is possible to appropriately perform processing to deal with the case where the compressor (50) is in a "liquid compression state in which a liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65)."

[0023] A seventh aspect of the present disclosure is a control device according to any one of the first to sixth aspects, wherein the physical quantity is any one of a rotation frequency of the motor (60), a voltage applied to the motor (60), a current flowing through the motor (60), vibration of the compressor (50), sound of the compressor (50), and sound around the compressor (50).

[0024] An eighth aspect of the present disclosure is the control device according to any one of the first to seventh aspects, wherein the frequency of the specific frequency component is a frequency synchronized with the rotation frequency of the motor (60).

[0025] A ninth aspect of the present disclosure relates to a refrigeration system, the refrigeration system including a refrigerant circuit (RR1) including a compressor (50) having a motor (60) and a compression mechanism (65), and the control device (30), wherein the control device (30) is any one of the control devices of the first to eighth aspects.

[0026] A tenth aspect of the present disclosure relates to a control method for controlling a system including a compressor (50) having a motor (60) and a compression mechanism (65), the control method comprising: an acquisition step of acquiring a physical quantity correlated with a state of the compressor (50); an output step of outputting information indicating that the state of the compressor (50) is a predetermined state when an index value indicating a magnitude of a temporal change of a specific frequency component included in the physical quantity acquired in the acquisition step satisfies a predetermined relationship with a predetermined threshold; and a handling step of performing at least one of a change step of changing an operating condition of the system.

[0027] In the eleventh aspect, a countermeasure step is performed when a relationship between an index value indicating the magnitude of change over time of a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and a predetermined threshold value satisfies a predetermined relationship, thereby making it possible to appropriately perform processing to counter the case where the state of the compressor (50) is in a predetermined state (a state in which the specific frequency component changes suddenly).

[0028] An eleventh aspect of the present disclosure is a control program that causes a computer to execute the control method of the tenth aspect. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a block diagram illustrating the configuration of a drive system according to an embodiment. [Figure 2] FIG. 2 is a vertical cross-sectional view illustrating an example of the internal configuration of the compressor. [Figure 3] FIG. 3 is a graph illustrating the relationship between the oil amount and the specific frequency component. [Figure 4] FIG. 4 is a graph illustrating an example of the temporal change in a specific frequency component before and after the occurrence of an oil amount abnormality. [Figure 5] FIG. 5 is a graph illustrating the change over time of a specific frequency component when the oil amount is normal and when the sealing performance of the compression chamber due to the lubricating oil breaks down. [Figure 6]FIG. 6 is a graph illustrating an example of the change over time of a specific frequency component during liquid compression. [Figure 7] FIG. 7 is a graph illustrating the change over time of a specific frequency component during normal operation and the change over time of a specific frequency component when liquid compression occurs. [Figure 8] FIG. 8 is a flowchart illustrating an estimation process performed by the control unit. [Figure 9] FIG. 9 is a graph for explaining the first estimation process. [Figure 10] FIG. 10 is a graph for explaining the second estimation process. [Figure 11] FIG. 11 is a graph for explaining the third estimation process. [Figure 12] FIG. 12 is a graph illustrating the first moving average value and the second moving average value. [Figure 13] FIG. 13 is a graph for explaining the fourth estimation process. [Figure 14] FIG. 14 is a piping diagram illustrating the configuration of a refrigeration system. [Figure 15] FIG. 15 is a graph for explaining the derivation of the amplitude value of a specific frequency component. [Figure 16] FIG. 16 is a graph illustrating the fluctuation of the index value according to the state of the compressor. [Figure 17] FIG. 17 is a graph illustrating an example of the change in torque over time in a two-cylinder compressor. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and their description will not be repeated.

[0031] (Embodiment) FIG. 1 illustrates the configuration of a drive system (10) according to an embodiment. The drive system (10) drives a motor (60) using electric power supplied from a power source (5). The motor (60) is mounted on a compressor (50). The compressor (50) includes a compression mechanism (65) in addition to the motor (60). The compression mechanism (65) is driven by the motor (60), sucks in a working fluid, compresses it, and discharges the compressed working fluid. For example, the working fluid is a refrigerant.

[0032] In this example, the power source (5) is a three-phase AC power source, and the motor (60) is a three-phase AC motor. For example, the motor (60) is an interior permanent magnet motor (IPM motor). The drive system (10) is mounted on the device (1). For example, the device (1) is an outdoor unit of an air conditioner. The drive system (10) includes a motor drive device (20) and a control device (30).

[0033] [Motor drive device] The motor drive device (20) drives the motor (60). Specifically, the motor drive device (20) converts power supplied from the power source (5) into output AC power (three-phase AC power in this example) having a predetermined frequency and voltage, and supplies the output AC power to the motor (60). In this example, the motor drive device (20) includes a converter (21), a DC unit (22), and an inverter (23).

[0034] The converter (21) rectifies the power supplied from the power source (5). In this example, the converter (21) full-wave rectifies the AC power supplied from the power source (5). For example, the converter (21) is configured with a diode bridge circuit in which a plurality of rectifying diodes are connected in a bridge configuration.

[0035] The DC unit 22 generates DC power according to the power supply power supplied from the power supply 5. In this example, the DC unit 22 has a capacitor and smoothes the output of the converter 21.

[0036] The inverter (23) has a plurality of switching elements and converts the output of the DC unit (22) into output AC power (three-phase AC power) having a predetermined frequency and voltage through switching operations of the plurality of switching elements. The inverter (23) is an example of a conversion unit that converts the DC power generated by the DC unit (22) into AC power through switching operations.

[0037] In this example, the inverter (23) has six bridge-connected switching elements and six freewheeling diodes connected in anti-parallel to each of the six switching elements. More specifically, the inverter (23) has three switching legs, each consisting of two switching elements connected in series. The midpoints of the three switching legs (specifically, the connection points between the upper-arm switching element and the lower-arm switching element) are connected to the three windings (U-phase, V-phase, and W-phase windings) of the motor (60), respectively.

[0038] [Various sensors] The motor drive device (20) is provided with various sensors such as a phase current detector (41) and an electrical angular frequency detector (42). Various pieces of information detected by the various sensors are transmitted to the control device (30). Specifically, the detection signals of the various sensors are transmitted to a control unit (31) described later. The various sensors are an example of a detector that detects information for obtaining physical quantities correlated with the state of the compressor (50). In addition, the drive system (10) and a refrigeration system (RR) described later are also provided with various sensors for obtaining the various physical quantities.

[0039] The phase current detection unit (41) detects three-phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)) flowing through three windings (not shown) of the motor (60). For example, the phase current detection unit (41) may detect all of the three-phase currents (iu, iv, iw), or may detect two of the three-phase currents (iu, iv, iw) and derive the remaining phase current based on the detected two-phase currents. Alternatively, the phase current detection unit (41) may derive the three-phase currents (iu, iv, iw) from a switching pattern and a DC current detected by a shunt resistor (not shown) provided in the DC unit (22).

[0040] The electrical angular frequency detection unit 42 detects the electrical angular frequency (ω) of the motor 60. Note that the electrical angular frequency detection unit 42 is not an essential component, and the electrical angular frequency (ω) of the motor 60 may be calculated by other methods or estimated in a sensorless manner.

[0041] [Control device (state estimation device)] The control device (30) estimates the state of the compressor (50). The control device (30) is an example of a state estimation device that estimates the state of the compressor (50). The processing in the control device (30) (processing related to the estimation of the state of the compressor (50)) is an example of a state estimation method that estimates the state of the compressor (50). Furthermore, the processing in the control device (30) (processing related to the control of a system including the compressor (50)) is an example of a control method that controls a system including the compressor (50).

[0042] In this example, the control device (30) estimates the state of the compressor (50) and performs processing according to the estimated state of the compressor (50). The control device (30) also controls the motor (60). Specifically, the control device (30) controls the motor (60) by controlling the motor drive device (20).

[0043] [Control Unit] The control device (30) includes a control unit (31). The control unit (31) performs various processes. Specifically, the control unit (31) acquires information and data from each unit of the device (1) and performs various processes based on the information and data. The processes performed by the control unit (31) will be described in detail later.

[0044] For example, the control unit 31 includes a processor and a memory electrically connected to the processor and storing a program for operating the processor. The processor executes the program to realize various functions of the control unit 31. The control unit 31 is an example of a computer, and the program is an example of a state estimation program and an example of a control program.

[0045] [Processing by the control unit] In this example, the control unit (31) performs estimation processing, control processing, and response processing.

[0046] [Estimation process] In the estimation process, the control unit (31) estimates the state of the compressor (50). Specifically, the control unit (31) estimates the state of the compressor (50) based on the magnitude of a temporal change in a specific frequency component included in a physical quantity correlated with the state of the compressor (50). For example, the magnitude of the temporal change in the specific frequency component is represented by the amount of change in the specific frequency component per unit time. In the estimation process, it is estimated whether the state of the compressor (50) is a "state in which the specific frequency component changes suddenly (specifically, a sudden increase or a sudden decrease)." The estimation process will be described in detail later.

[0047] [Control Processing] In the control process, the control unit (31) controls the motor drive device (20) to control the motor (60). Specifically, the control unit (31) receives as input a target command value, such as a command value for the electrical angular frequency (ω) of the motor (60), and detection signals from various sensors provided in the motor drive device (20). Based on the target command value, the detection signals from the various sensors, and the like, the control unit (31) controls the switching operation of the inverter (23) to control the AC power supplied from the inverter (23) to the motor (60).

[0048] [Countermeasures] In this example, when the control unit (31) estimates in the estimation process that the state of the compressor (50) is “a state in which the specific frequency component changes suddenly,” the control unit (31) performs a countermeasure process. The countermeasure process is a process for dealing with the “state in which the specific frequency component changes suddenly” of the compressor (50), and includes at least one of an output process for outputting first information indicating that the state of the compressor (50) is “a state in which the specific frequency component changes suddenly” and a change process for changing the operating conditions of the motor (60).

[0049] Examples of the output process include the following first output process, second output process, third output process, and combinations thereof. The first output process is a process of outputting the first information to a display device (not shown) provided on a remote controller or the like, thereby displaying the first information on the display device. The second output process is a process of outputting the first information to a control unit (not shown) that controls the operation of the device (1), thereby causing the control unit to perform an operation to deal with an abnormal state. The third output process is a process of uploading the first information to a data storage unit (not shown) on the cloud.

[0050] Examples of the change process include the following first change process, second change process, third change process, and combinations thereof. The first change process is a process for stopping the motor (60). The second change process is a process for accelerating the motor (60). The third change process is a process for decelerating the motor (60).

[0051] [Compressor details] As shown in Fig. 2, the compressor (50) is a hermetic scroll compressor. The compressor (50) includes a casing (51), a motor (60), a compression mechanism (65), a first support (80), and a second support (85). The motor (60), the compression mechanism (65), the first support (80), and the second support (85) are housed in the casing (51).

[0052] <Casing> The casing (51) is a cylindrical sealed container with closed ends and its axial direction is the up-down direction. Arranged in this order from top to bottom in the interior space of the casing (51) are a compression mechanism (65), a first support (80), a motor (60), and a second support (85). An oil reservoir (54) for storing lubricating oil (refrigeration oil) is formed in the bottom of the casing (51).

[0053] The casing (51) has a suction pipe (52) and a discharge pipe (53). The suction pipe (52) penetrates the top of the casing (51) and is connected to the compression mechanism (65). The suction pipe (52) guides low-pressure working fluid from outside the compressor (50) to the compression mechanism (65). The discharge pipe (53) penetrates the body of the casing (51) and opens into the internal space of the casing (51) (the space below the second support portion (85)). The discharge pipe (53) guides the high-pressure working fluid, which has been discharged from the compression chamber (68) and then guided to the space below the second support portion (85) of the casing (51), to the outside of the compressor (50). With this configuration, the pressure of the high-pressure working fluid discharged from the compression chamber (68) acts on the space below the second support portion (85) of the casing (51) (including the oil reservoir portion (54)).

[0054] <Motor> The motor (60) has a stator (61) and a rotor (62). The stator (61) is fixed to the body of the casing (51). The rotor (62) is disposed inside the stator (61). A drive shaft (70) is inserted through the rotor (62).

[0055] <First support part> The first support portion (80) includes a main body portion (81) and a first bearing portion (82). The main body portion (81) is formed in the shape of a thick disk and is fixed to the casing (51). A crank chamber (81a) is formed in the center of the main body portion (81). The crank chamber (81a) is a cylindrical recess that opens to the front surface (top surface in FIG. 2) of the main body portion (81). The first bearing portion (82) is formed in the shape of a cylinder that protrudes from the rear surface (bottom surface in FIG. 2) of the main body portion (81) and is located in the center of the main body portion (81). A through hole for inserting the drive shaft (70) therethrough is formed in the first bearing portion (82). A first bearing (91), which will be described later, is fitted into this through hole.

[0056] <Second support part> The second support part (85) includes a second bearing part (86) and three legs (87). The second bearing part (86) is formed in a thick-walled cylindrical shape. A second bearing (92), which will be described later, is fitted into the second bearing part (86). The legs (87) extend radially from the second bearing part (86). The protruding ends of the legs (87) of the second support part (85) are fixed to the body of the casing (51).

[0057] <Compression mechanism> The compression mechanism (65) is a scroll-type fluid machine. The compression mechanism (65) includes a fixed scroll (66) and an orbiting scroll (67). The wraps of the fixed scroll (66) and the orbiting scroll (67) are meshed with each other to form a compression chamber (68).

[0058] The fixed scroll (66) includes a fixed end plate (66a), a fixed wrap (66b), and an outer peripheral wall (66c). The fixed end plate (66a) is a relatively thick, flat plate-like portion located at the upper portion of the fixed scroll (66). The fixed wrap (66b) is formed in the shape of a spiral wall and protrudes from the front surface (the lower surface in FIG. 2) of the fixed end plate (66a). The outer peripheral wall (66c) is formed so as to surround the outer periphery of the fixed wrap (66b) and protrudes from the front surface (the lower surface in FIG. 2) of the fixed end plate (66a). The outer peripheral wall (66c) is fixed to a first support portion (80) fixed to the casing (51). An intake port (sp) is formed in the outer peripheral wall (66c), and the intake pipe (52) is inserted into the outer peripheral wall (66c). The fixed end plate portion (66a) is formed with a discharge port (dp).

[0059] The orbiting scroll (67) includes an orbiting-side end plate (67a), an orbiting-side lap (67b), and a boss (67c). The orbiting-side end plate (67a) is formed in a generally circular, flat plate shape. The orbiting-side lap (67b) is formed in a spiral wall shape and protrudes from the front surface (upper surface in FIG. 2) of the orbiting-side end plate (67a). The boss (67c) is formed in a cylindrical shape that protrudes from the back surface (lower surface in FIG. 2) of the orbiting-side end plate (67a) and is disposed in the center of the orbiting-side end plate (67a). A third bearing (93), which will be described later, is fitted into the boss (67c).

[0060] (Drive shaft) The drive shaft (70) includes a main shaft portion (71) and an eccentric shaft portion (72). The main shaft portion (71) includes a main journal portion (71a), a sub-journal portion (71b), and an intermediate shaft portion (71c). The drive shaft (70) is disposed in an orientation in which the eccentric shaft portion (72) is located above the main shaft portion (71).

[0061] The main shaft portion (71) includes, in order from one end to the other, a main journal portion (71a), an intermediate shaft portion (71c), and an auxiliary journal portion (71b). The main journal portion (71a), the intermediate shaft portion (71c), and the auxiliary journal portion (71b) are each formed in a cylindrical shape and are arranged coaxially with one another. The main journal portion (71a) has a larger diameter than the intermediate shaft portion (71c), and the auxiliary journal portion (71b) has a smaller diameter than the intermediate shaft portion (71c). The main journal portion (71a) is located above the intermediate shaft portion (71c), and the auxiliary journal portion (71b) is located below the intermediate shaft portion (71c).

[0062] The main journal portion (71a) is inserted into a first bearing (91) fitted in a first bearing portion (82) of the first support portion (80) and is supported by the first bearing (91). The sub-journal portion (71b) is inserted into a second bearing (92) fitted in a second bearing portion (86) of the second support portion (85) and is supported by the second bearing (92). The intermediate shaft portion (71c) is inserted into a rotor (62) of the motor (60) and is fixed to the rotor (62).

[0063] The eccentric shaft portion (72) is formed in the shape of a relatively short shaft and protrudes from an end surface of the main journal portion (71a). The eccentric shaft portion (72) is located higher than the main shaft portion (71). The axis of the eccentric shaft portion (72) is substantially parallel to the axis of the main shaft portion (71) and is eccentric with respect to the axis of the main shaft portion (71). The eccentric shaft portion (72) is inserted into the inside of a third bearing (93) fitted into the boss portion (67c) of the orbiting scroll (67) and is supported by the third bearing (93).

[0064] (Bearings) The first bearing (91), the second bearing (92), and the third bearing (93) are all cylindrically shaped sliding bearings that support the drive shaft (70).

[0065] The first bearing (91) is fitted inside the first bearing portion (82) of the first support portion (80). The main journal portion (71 a) of the drive shaft (70) is inserted into the inside of the first bearing (91), and the first bearing (91) supports the main journal portion (71 a) of the drive shaft (70).

[0066] The second bearing (92) is fitted inside the second bearing portion (86) of the second support portion (85). The sub-journal portion (71b) of the drive shaft (70) is inserted into the inside of the second bearing (92), and the second bearing (92) supports the sub-journal portion (71b) of the drive shaft (70).

[0067] The third bearing (93) is fitted inside the boss portion (67c) of the orbiting scroll (67). The eccentric shaft portion (72) of the drive shaft (70) is inserted into the inside of the third bearing (93), and the third bearing (93) supports the eccentric shaft portion (72) of the drive shaft (70).

[0068] (Fueling route) The compressor (50) is provided with an oil supply path (100). The oil supply path (100) is a path (passage) for supplying lubricating oil (refrigeration oil) stored in an oil reservoir (54) formed in the bottom of the casing (51) to sliding parts. The oil supply path (100) has a main oil supply path (101) and an auxiliary oil supply path (102).

[0069] The main oil supply path (101) is formed in the drive shaft (70). The main oil supply path (101) has a main path extending in the axial direction from one end to the other end (from the lower end to the upper end in FIG. 2 ) of the drive shaft (70), and branch paths branching from the main path toward the “sliding portion of the drive shaft (70) with the first bearing (91),” the “sliding portion of the drive shaft (70) with the second bearing (92),” and the “sliding portion of the drive shaft (70) with the third bearing (93).” The main oil supply path (101) guides lubricating oil (refrigeration oil) stored in the oil reservoir (54) to the sliding portions of the drive shaft (70) with the bearings (specifically, the first bearing (91), the second bearing (92), and the third bearing (93)).

[0070] The auxiliary oil supply path (102) is formed to extend between the first support portion (80) and the fixed scroll (66) and guides the lubricating oil stored in the crank chamber (81a) to the compression chamber (68) of the compression mechanism (65) (specifically, to the gap between the fixed scroll (66) and the orbiting scroll (67)). The auxiliary oil supply path (102) is formed so that one end opens in the crank chamber (81a) and the other end opens in the gap between the outer peripheral wall portion (66c) of the fixed scroll (66) and the orbiting-side end plate (67a) of the orbiting scroll (67). The crank chamber (81a) is configured to collect the lubricating oil that has been guided from the oil reservoir (54) through the main oil supply path (101) to the sliding portion between the drive shaft (70) and the third bearing (93) and has flowed out from the sliding portion after lubricating the sliding portion. The auxiliary oil supply path (102) guides the lubricating oil, which has lubricated the sliding portions of the drive shaft (70) and the third bearing (93), from the crank chamber (81a) to the compression mechanism (65). The lubricating oil guided to the compression mechanism (65) seals the compression chamber (68) (specifically, the gap between the fixed scroll (66) and the orbiting scroll (67)).

[0071] With this configuration, the lubricating oil in the oil reservoir (54) on which the pressure (high pressure) of the working fluid discharged from the compression mechanism (65) acts flows into the main oil supply path (101) through the suction port (101a) of the main oil supply path (101), flows through the main oil supply path (101), and is supplied to sliding portions between the drive shaft (70) and the bearings (specifically, the first bearing (91), the second bearing (92), and the third bearing (93)). The lubricating oil supplied to the sliding portions between the drive shaft (70) and the third bearing (93) lubricates the sliding portions between the drive shaft (70) and the third bearing (93), and thereafter is stored in the crank chamber (81a). The lubricating oil stored in the crank chamber (81a) is supplied to the compression chamber (68) of the compression mechanism (65) (specifically, the gap between the fixed scroll (66) and the orbiting scroll (67)) via the auxiliary oil supply path (102), thereby sealing the compression chamber (68).

[0072] [Findings Obtained by the Inventors of the Present Application] As a result of extensive research, the inventors of the present application have found that the state of the compressor (50) having the motor (60) and the compression mechanism (65) is in a state where a specific frequency component included in a physical quantity correlated with the state of the compressor (50) suddenly changes.

[0073] Specifically, the inventors of the present application have found a phenomenon in which "when the sealing performance of the compression chambers (68) of the compressor (50) by the lubricating oil is broken down, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes suddenly." In particular, the inventors of the present application have found a phenomenon in which "when the suction port (101a) of the oil supply path (100) of the compressor (50) is no longer immersed in the lubricating oil accumulated in the oil reservoir (54), the sealing performance of the compression chambers (68) by the lubricating oil breaks down, and as a result, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes suddenly."

[0074] The inventors of the present application have also discovered the following phenomenon: "When a liquid working fluid is sucked into the compression mechanism (65) in the compressor (50) and compressed in the compression mechanism (65), a specific frequency component contained in a physical quantity correlated with the state of the compressor (50) suddenly changes."

[0075] Furthermore, the inventors of the present application have found that the above-described state (the state of the compressor (50) in which the specific frequency component changes suddenly) can be estimated based on the magnitude of the change over time of the specific frequency component contained in the physical quantity.

[0076] The findings of the present inventors will be described in detail below. In the following, an example will be described in which the physical quantity correlated with the state of the compressor (50) is the "current vector amplitude (Ia)" and the specific frequency component included in the physical quantity is a "frequency component having a frequency equal to one times the mechanical angular frequency of the motor (60) (hereinafter referred to as a "first-order component"). The "current vector amplitude (Ia)" is an example of a physical quantity correlated with the torque of the compressor (50) and is also an example of a physical quantity correlated with the voltage or current of the motor (60). The mechanical angular frequency of the motor (60) corresponds to the rotational frequency of the motor (60).

[0077] [Breakdown of sealing performance of compression chamber (68) due to lubricating oil] First, with reference to Fig. 2, a breakdown in the sealing performance of the compression chamber (68) will be described. In the compressor (50), when the suction port (101a) of the oil supply path (100) is no longer immersed in the lubricating oil accumulated in the oil reservoir (54), the sealing performance of the compression chamber (68) provided by the lubricating oil breaks down, and the amplitude of torque pulsation of the compressor (50) suddenly decreases. Specifically, the magnitude of the first-order component of the rotational frequency of the motor (60) in the torque suddenly decreases. Therefore, when the sealing performance of the compression chamber (68) provided by the lubricating oil breaks down, the first-order component of the rotational frequency of the motor (60) in the current vector amplitude (Ia) suddenly decreases.

[0078] Next, a description will be given of changes in specific frequency components in response to changes in the amount of oil accumulated in the oil reservoir (54) with reference to Figures 3 and 4. In the following description, "oil amount" refers to the amount of oil accumulated in the oil reservoir (54). "Normal oil amount" refers to a state in which the suction port (101a) of the oil supply path (100) is immersed in the lubricating oil accumulated in the oil reservoir (54). "Abnormal oil amount" refers to a state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).

[0079] As shown in Fig. 3, as the amount of oil gradually decreases, the amplitude value of the specific frequency component gradually decreases. The amount of oil changes depending on the operating conditions of the compressor (50). As shown in Fig. 4, when the amount of oil changes from normal to abnormal at time (t1), the amplitude value of the specific frequency component suddenly drops.

[0080] 3 and 4, the amplitude value of the specific frequency component when the oil level is abnormal is smaller than the amplitude value of the specific frequency component when the oil level is abnormal. Therefore, in order to distinguish between a normal oil level and an abnormal oil level, it is conceivable to compare the magnitude (amplitude value) of the specific frequency component with a threshold value. However, in order to set the threshold value to be compared with the magnitude of the specific frequency component, it is necessary to take into account errors contained in the specific frequency component (such as sensor errors and errors due to the effects of pressure and temperature), which may make it difficult to set the threshold value appropriately.

[0081] For example, if the median value of the specific frequency component when the oil level is normal (e.g., the median of the expected change range) is 1.37 A and the median value of the specific frequency component when the oil level is abnormal is 0.75 A, it is desirable to set the threshold value for distinguishing between normal and abnormal oil levels between 0.75 A and 1.37 A. However, the value of the specific frequency component when the oil level is normal varies depending on errors (e.g., sensor errors, errors due to pressure and temperature) and the oil level, with the minimum value being 0.85 A. Similarly, the value of the specific frequency component when the oil level is abnormal also varies depending on errors, with the maximum value being 1.23 A. Therefore, it is difficult to set the threshold value appropriately. The value of the specific frequency component varies depending on errors and oil level because the waveform of a physical quantity (a physical quantity correlated with the state of the compressor (50)) changes depending on the errors and oil level.

[0082] As shown in FIG. 5, the change over time of the specific frequency component when the sealing performance of the compression chamber (68) is broken down by the lubricating oil (the change over time during the period (TA) in the example of FIG. 5) is significantly larger than the change over time of the specific frequency component accompanying an increase or decrease in the oil amount when the oil amount is normal (the change over time during the period (TB) in the example of FIG. 5). The vertical axis of FIG. 5 indicates the percentage (proportion to the reference) of the amplitude value of the specific frequency component, with the amplitude value of the specific frequency component at the start of the period (TB) being the reference (100%). For example, the change over time of the specific frequency component when the sealing performance of the compression chamber (68) is broken down by the lubricating oil is a "change of 40% decrease over 30 seconds (1.333% / second)," while the change over time of the specific frequency component accompanying an increase or decrease in the oil amount when the oil amount is normal is a "change of 11% decrease over 1800 seconds (0.006% / second)."

[0083] Therefore, based on the magnitude of the change over time of the specific frequency component, it is possible to identify a sudden change (specifically, a sudden drop) of the specific frequency component that occurs when the sealing performance of the compression chamber (68) by the lubricant is broken. For example, by comparing a value indicating the magnitude of the change over time of the specific frequency component with a threshold value, it is possible to estimate whether the state of the compressor (50) is “a state in which the sealing performance of the compression chamber (68) by the lubricant is broken.”

[0084] Furthermore, since the threshold value to be compared with the magnitude of the temporal change of the specific frequency component is set, it is not necessary to consider the error contained in the specific frequency component (such as the sensor error or the error due to the influence of pressure and temperature), which makes it possible to set the threshold value more appropriately than when setting the threshold value to be compared with the magnitude of the specific frequency component.

[0085] Specifically, the change over time of the specific frequency component accompanying the change in pressure and temperature is sufficiently smaller than the change over time of the specific frequency component when the lubricating oil breaks down the sealing performance of the compression chamber (68). Also, the change over time of the specific frequency component accompanying the change in pressure and temperature is sufficiently smaller than the difference between the "change over time of the specific frequency component when the lubricating oil breaks down the sealing performance of the compression chamber (68)" and the "change over time of the specific frequency component accompanying an increase or decrease in the oil amount when the oil amount is normal."

[0086] In order to reduce the error contained in the specific frequency component, it is conceivable to prepare a separate threshold for each sensor or for each pressure and temperature. However, this method complicates the state estimation algorithm and increases the computational load, resulting in higher costs for processors and other computing devices. On the other hand, the method of the embodiment (state estimation based on the magnitude of temporal change in the specific frequency component) only requires setting a single threshold for the magnitude of temporal change in the specific frequency component, thereby suppressing the increase in computational load and allowing existing processors to be used as is.

[0087] Furthermore, in order to grasp the influence of the oil amount on the specific frequency component, it is conceivable to provide a separate sensor for detecting the oil amount. However, this method would increase costs due to the installation of the sensor. On the other hand, the method of the embodiment (state estimation based on the magnitude of temporal change in the specific frequency component) does not require a separate sensor for detecting the oil amount, so the increase in costs due to the installation of the sensor can be avoided.

[0088] Furthermore, the method in the embodiment (state estimation based on the magnitude of temporal change in a specific frequency component) can capture changes in the current waveform when an abnormality occurs by focusing on the frequency component. By monitoring the frequency component in this way, abnormalities can be detected more accurately than when monitoring the effective value or average value.

[0089] [Liquid compression] Next, liquid compression will be described with reference to Fig. 6. In the compressor (50), when a liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65), the amplitude of torque pulsation of the compressor (50) suddenly increases. Specifically, the magnitude of the first-order component of the rotational frequency of the motor (60) in the torque suddenly increases. Therefore, when liquid compression occurs, the magnitude of the first-order component of the rotational frequency of the motor (60) in the current vector amplitude (Ia) suddenly increases.

[0090] 6, when liquid compression occurs at time (t1), the amplitude value of the specific frequency component rises sharply. Thereafter, when the liquid working fluid is removed from the compression mechanism (65), the amplitude value of the specific frequency component returns to the original value.

[0091] Furthermore, as shown in Figure 6, the amplitude value of the specific frequency component during liquid compression is larger than the amplitude value of the specific frequency component during normal operation. Therefore, in order to distinguish between normal operation and liquid compression, it is conceivable to compare the magnitude (amplitude value) of the specific frequency component with a threshold value. However, in order to set the threshold value to be compared with the magnitude of the specific frequency component, it is necessary to take into account errors contained in the specific frequency component (such as sensor errors and errors due to the effects of pressure and temperature), which can make it difficult to set the threshold value appropriately.

[0092] For example, if the median value of a specific frequency component during normal operation (e.g., the median of the expected change range) is "1.37 A" and the median value of the specific frequency component during liquid compression is "1.96 A," it is desirable to set the threshold value for distinguishing between normal operation and liquid compression between "1.37 A" and "1.96 A." However, the value of the specific frequency component during normal operation varies depending on errors (sensor errors, errors due to pressure and temperature, etc.) and the amount of oil, with the maximum value being "1.89 A." Similarly, the value of the specific frequency component during liquid compression also varies depending on errors and the amount of oil, with the minimum value being "1.44 A." Therefore, the above threshold value cannot be set appropriately.

[0093] As shown in Figure 7, the change over time of the specific frequency component when liquid compression occurs (the change over time in period (TC) in the example of Figure 7) is significantly larger than the change over time of the specific frequency component during normal operation (the change over time in period (TD) in the example of Figure 7). The vertical axis of Figure 7 shows the percentage (proportion to the reference) of the amplitude value of the specific frequency component, with the amplitude value of the specific frequency component at the start of period (TD) being the reference (100%). For example, the change over time of the specific frequency component when liquid compression occurs is a "change of 43% increase over 20 seconds (2.15% / second)," while the change over time of the specific frequency component during normal operation is a "change of 11% increase or decrease over 1800 seconds (0.006% / second)."

[0094] Therefore, based on the magnitude of the temporal change in the specific frequency component, it is possible to identify a sudden change (specifically, a sudden increase) in the specific frequency component during liquid compression. For example, by comparing a value indicating the magnitude of the temporal change in the specific frequency component with a threshold value, it is possible to estimate whether the state of the compressor (50) is a "liquid compression state."

[0095] Furthermore, since the threshold value to be compared with the magnitude of the temporal change of the specific frequency component is set, it is not necessary to consider the error contained in the specific frequency component (such as the sensor error or the error due to the influence of pressure and temperature), which makes it possible to set the threshold value more appropriately than when setting the threshold value to be compared with the magnitude of the specific frequency component.

[0096] Specifically, the change over time of the specific frequency component accompanying changes in pressure and temperature is sufficiently smaller than the change over time of the specific frequency component when liquid compression occurs. Also, the change over time of the specific frequency component accompanying changes in pressure and temperature is sufficiently smaller than the difference between the "change over time of the specific frequency component when liquid compression occurs" and the "change over time of the specific frequency component during normal operation."

[0097] [Details of estimation process] In the estimation process, the control unit (31) estimates whether the state of the compressor (50) is “a state in which the specific frequency component changes suddenly” based on the magnitude of the change over time of the specific frequency component included in the physical quantity correlated with the state of the compressor (50). For example, the “state in which the specific frequency component changes suddenly” can be said to be “a state in which the amount of change per unit time of the specific frequency component exceeds a predetermined reference amount.”

[0098] In this example, the physical quantity is a physical quantity correlated with the torque of the compressor (50). The physical quantity is a physical quantity correlated with the voltage or current of the motor (60). The control unit (31) performs estimation processing based on the signal indicative of the physical quantity. Specific examples of the signal indicative of the physical quantity will be described in detail later.

[0099] In this example, the frequency of the specific frequency component is a frequency synchronized with the mechanical angular frequency of the motor (60). In other words, the frequency of the specific frequency component is a frequency corresponding to the mechanical angular frequency of the motor (60). Specifically, the frequency of the specific frequency component is an integer multiple of the mechanical angular frequency of the motor (60) or N / M times the mechanical angular frequency of the motor (60). Note that M and N are integers, and N <Mである。

[0100] In this example, in the estimation process, the control unit (31) estimates whether the compressor (50) is in a state where the sealing of the compression chambers by the lubricating oil has failed. Alternatively, the control unit (31) estimates whether the compressor (50) is in a liquid compression state where a liquid working fluid is sucked into the compression mechanism (65) and compressed therein.

[0101] In other words, in this example, the “state in which a specific frequency component changes suddenly” of the compressor (50) estimated by the control unit (31) is “a state in which the sealing of the compression chamber by the lubricating oil has been broken down” or “a liquid compression state in which a liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65).”

[0102] In this example, the "state in which the sealing performance of the compression chambers by the lubricating oil has been broken" specifically refers to the "state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54), and therefore the sealing performance of the compression chambers by the lubricating oil has been broken." The control unit (31) may estimate whether the compressor (50) is in the "state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54)."

[0103] [Flow of estimation process] Next, the flow of the estimation process will be described with reference to Fig. 8. The control unit (31) repeatedly performs the following process.

[0104] <Step (S1): Acquisition Step> First, the control unit (31) acquires a physical quantity (e.g., a current vector amplitude (Ia)) correlated with the state of the compressor (50). In this example, the control unit (31) acquires the physical quantity at each predetermined derivation time based on information obtained by various sensors (information for obtaining the physical quantity correlated with the state of the compressor (50)). By repeating such processing, the physical quantity is obtained at each derivation time.

[0105] The sensor for acquiring “information for obtaining physical quantities correlated with the state of the compressor (50)” in the estimation process may also be used as a sensor (e.g., a current sensor) used in the control process, or may be a sensor provided separately from the sensor used in the control process.

[0106] Step (S2): Estimation Step Next, the control unit (31) estimates the state of the compressor (50) based on the magnitude of change over time of a specific frequency component (e.g., a first-order component) included in the physical quantity obtained in step (S1). In this example, the control unit (31) derives, at each predetermined estimation time, a value (hereinafter referred to as an “index value”) indicating the magnitude of change over time of a specific frequency component included in the physical quantity based on the physical quantity obtained in step (S1). The control unit (31) then compares the index value with a threshold value and, based on the comparison result, estimates whether the state of the compressor (50) is a “state in which the specific frequency component changes suddenly.” By repeating this process, an index value is derived at each estimation time, and the state of the compressor (50) is estimated based on the index value. A specific example of the estimation process will be described in detail later.

[0107] [Effects of the embodiment] As described above, in the drive system (10) of the embodiment, the control unit (31) estimates the state of the compressor (50) in the estimation process based on the magnitude of the change over time in a specific frequency component contained in a physical quantity correlated with the state of the compressor (50).

[0108] According to the above configuration, by estimating the state of the compressor (50) based on the magnitude of the change over time of the specific frequency component, it is possible to estimate whether the state of the compressor (50) is a “state in which the specific frequency component changes suddenly.”

[0109] In the drive system (10) of the embodiment, the compression mechanism (65) has a compression chamber (68) for compressing the working fluid. The compression chamber (68) is sealed with lubricating oil. In the estimation process, the control unit (31) estimates whether the state of the compressor (50) is “a state in which the sealing performance of the compression chamber (68) by the lubricating oil has been broken down.”

[0110] According to the above configuration, it is possible to estimate that the state of the compressor (50) is “a state in which the sealing performance of the compression chamber (68) by the lubricating oil has been broken down” based on the magnitude of the change over time of the specific frequency component.

[0111] In the drive system (10) of the embodiment, the compression mechanism (65) has a compression chamber (68) for compressing the working fluid. The compressor (50) has an oil reservoir (54) for storing lubricating oil, and an oil supply path (100) for supplying the lubricating oil stored in the oil reservoir (54) to the compression chamber (68). The oil supply path (100) has a suction port (101a). The suction port (101a) is immersed in the lubricating oil stored in the oil reservoir (54), thereby enabling the lubricating oil sucked through the suction port (101a) to be supplied to the compression chamber (68). The compression chamber (68) is sealed with the lubricating oil. In the estimation process, the control unit (31) estimates whether the compressor (50) is in a state where the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).

[0112] According to the above configuration, it is possible to estimate, based on the magnitude of the temporal change in the specific frequency component, that the state of the compressor (50) is “a state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).”

[0113] In addition, in the drive system (10) of the embodiment, the control unit (31) estimates, in the estimation process, whether the state of the compressor (50) is a “liquid compression state in which a liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65).”

[0114] According to the above configuration, it is possible to estimate, based on the magnitude of the temporal change in the specific frequency component, that the state of the compressor (50) is a "liquid compression state in which the liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65)."

[0115] (Example of a signal indicating a physical quantity) Next, a specific example of a signal indicating a physical quantity correlated with the voltage or current of the motor (60) will be described. Such signals are broadly classified into DC signals and AC signals.

[0116] [Example of DC signal] Examples of DC signals include a "signal correlated to the phase currents (iu, iv, iw) of the motor (60)," a "signal correlated to the phase voltages (Vu, Vv, Vw) of the motor (60)," and a "signal correlated to the power of the motor (60)."

[0117] Other examples of DC signals include "currents (iγ, iδ) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) with the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (60)" and "voltages (Vγ, Vδ) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (60)." )," "currents (iζ, iη) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (60)," and "voltages (Vζ, Vη) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) with the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (60)."

[0118] Further examples of DC signals include "dq-axis magnetic flux (λd, λq) coordinate-transformed to match the armature flux linkage caused by the permanent magnet" and "the magnitude of the armature flux linkage vector λ0, which is the composite of the armature flux linkage of the permanent magnet and the armature reaction."

[0119] In the following description, the term "phase currents (iu, iv, iw) of the motor (60)" refers to the phase currents (iu, iv, iw) of the motor (60) detected by the phase current detection unit (41). The term "phase voltages (Vu, Vv, Vw) of the motor (60)" refers to the phase voltages (Vu, Vv, Vw) of the motor (60) indicated in a voltage command value used within the control unit (31) or the phase voltages (Vu, Vv, Vw) of the motor (60) detected by a phase voltage detection unit (not shown) provided in the motor drive device (20). The term "electrical angular frequency (ω) of the motor (60)" refers to the electrical angular frequency (ω) of the motor (60) detected by the electrical angular frequency detection unit (42).

[0120] [1. Specific examples of signals correlated with motor phase currents] Specific examples of signals correlated with the phase currents (iu, iv, iw) of the motor (60) include the current vector amplitude (Ia), the square of the current vector amplitude (Ia 2 ), phase current amplitude (I), and phase current effective value (Irms).

[0121] The current vector amplitude (Ia) and the square of the current vector amplitude (Ia 2 ) is an example of a value proportional to the sum of the squares of the three phase currents (iu, iv, iw) of the motor (60). The value proportional to the sum of the squares of the three phase currents (iu, iv, iw) of the motor (60) is an example of a value proportional to an integer power of the magnitude of the phase currents (iu, iv, iw) of the motor (60).

[0122] (1) Current vector amplitude The current vector amplitude (Ia) is derived based on the phase currents (iu, iv, iw) of the motor (60). Alternatively, the current vector amplitude (Ia) may be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (60) into a fixed coordinate system. Alternatively, the current vector amplitude (Ia) may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (60) using an angle based on the direction of the primary magnetic flux. Alternatively, the current vector amplitude (Ia) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (60) using an angle based on the direction of the magnetic pole position. Specifically, the current vector amplitude (Ia) can be expressed as follows:

[0123]

number

[0124] (2) Square of the current vector amplitude The squared value of the current vector amplitude (Ia 2 ) is derived based on the phase currents (iu, iv, iw) of the motor (60). 2 ) may be derived based on the α-phase current (iα) and the β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (60) into a fixed coordinate system. 2 ) may be derived based on the M-axis current (iM) and the T-axis current (iT) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) by an angle based on the direction of the primary magnetic flux. 2 ) may be derived based on the d-axis current (id) and the q-axis current (iq) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) by an angle based on the orientation of the magnetic pole position. Specifically, the square value of the current vector amplitude (Ia 2 ) can be expressed as the following formula:

[0125]

number

[0126] (3) Phase current amplitude The phase current amplitude (I) is derived based on one of the phase currents (iu, iv, iw) of the motor (60), for example, the U-phase current (iu), and the phase current phase (ωi). The phase current phase (ωi) is derived based on the phase currents (iu, iv, iw) of the motor (60), for example. Specifically, the phase current amplitude (I) can be expressed by the following equation:

[0127]

number

[0128] (4) Phase current effective value The phase current effective value (Irms) is derived based on the phase current amplitude (I). Specifically, the phase current effective value (Irms) can be expressed as follows:

[0129]

number

[0130] (5) Other In the above description, the current vector amplitude (Ia) is derived based on the three phase currents (iu, iv, iw) of the motor (60) as an example. However, the current vector amplitude (Ia) may be derived based on two of the three phase currents (iu, iv, iw) of the motor (60). The current vector amplitude (Ia) may also be derived based on a DC current of the inverter (23) detected by a DC current detector (e.g., a shunt resistor, not shown) provided in the motor drive device (20). The square value (Ia) of the current vector amplitude 2 ) is also the same.

[0131] [2. Specific examples of signals correlated with motor phase voltages] Specific examples of signals correlated with the phase voltages (Vu, Vv, Vw) of the motor (60) include the voltage vector amplitude (Va), the square value of the voltage vector amplitude (Va 2 ), phase voltage amplitude (V), and phase voltage effective value (Vrms).

[0132] The voltage vector amplitude (Va) and the square of the voltage vector amplitude (Va 2 ) is an example of a value proportional to the sum of the squares of the three phase voltages (Vu, Vv, Vw) of the motor (60). The value proportional to the sum of the squares of the three phase voltages (Vu, Vv, Vw) of the motor (60) is an example of a value proportional to an integer power of the magnitude of the phase voltages (Vu, Vv, Vw) of the motor (60).

[0133] (1) Voltage vector amplitude The voltage vector amplitude (Va) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (60). Alternatively, the voltage vector amplitude (Va) may be derived based on an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (60) into a fixed coordinate system. Alternatively, the voltage vector amplitude (Va) may be derived based on an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the direction of the primary magnetic flux. Alternatively, the voltage vector amplitude (Va) may be derived based on a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the direction of the magnetic pole position. Specifically, the voltage vector amplitude (Va) can be expressed as follows:

[0134]

number

[0135] (2) Squared value of voltage vector amplitude The squared value of the voltage vector magnitude (Va 2 ) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (60).2 ) may be derived based on an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (60) into a fixed coordinate system. 2 ) may be derived based on the M-axis voltage (VM) and the T-axis voltage (VT) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the direction of the primary magnetic flux. 2 ) may be derived based on the d-axis voltage (Vd) and the q-axis voltage (Vq) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the orientation of the magnetic pole position. Specifically, the square value of the voltage vector amplitude (Va 2 ) can be expressed as the following formula:

[0136]

number

[0137] (3) Phase voltage amplitude The phase voltage amplitude (V) is derived based on one of the phase voltages (Vu, Vv, Vw) of the motor (60), for example, the U-phase voltage (Vu), and the phase voltage phase (ωv). The phase voltage phase (ωv) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (60), for example. Specifically, the phase voltage amplitude (V) can be expressed by the following equation:

[0138]

number

[0139] (4) Phase voltage effective value The phase voltage effective value (Vrms) is derived based on the phase voltage amplitude (V). Specifically, the phase voltage effective value (Vrms) can be expressed as follows:

[0140]

number

[0141] (5) Other In the above description, the voltage vector amplitude (Va) is calculated based on the three phase voltages (Vu, Vv, Vw) of the motor (60). However, the voltage vector amplitude (Va) may be calculated based on two of the three phase voltages (Vu, Vv, Vw) of the motor (60). 2 ) is also the same.

[0142] [3. Specific examples of signals correlated with motor power] Examples of signals correlated to the power of the motor (60) include instantaneous power (p), instantaneous imaginary power (q), apparent power (S), active power (P), and reactive power (Q).

[0143] (1) Instantaneous power The instantaneous power (p) is derived based on the phase currents (iu, iv, iw) of the motor (60) and the phase voltages (Vu, Vv, Vw) of the motor (60). Alternatively, the instantaneous power (p) may be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (60) into a fixed coordinate system, and an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (60) into the fixed coordinate system. The instantaneous power (p) may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (60) using an angle based on the direction of the primary magnetic flux, and an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (60) using an angle based on the direction of the primary magnetic flux. The instantaneous power (p) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (60) using an angle based on the direction of the magnetic pole position, and a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (60) using an angle based on the direction of the magnetic pole position. Specifically, the instantaneous power (p) can be expressed as follows:

[0144]

number

[0145] (2) Instantaneous reactive power The instantaneous imaginary power (q) is derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (60) into a fixed coordinate system, and an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (60) into a fixed coordinate system. Alternatively, the instantaneous imaginary power (q) may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (60) by an angle based on the direction of the primary magnetic flux, and an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the direction of the primary magnetic flux. Furthermore, the instantaneous imaginary power (q) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (60) by an angle based on the orientation of the magnetic pole position, and a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the orientation of the magnetic pole position. Specifically, the instantaneous imaginary power (q) can be expressed by the following equation:

[0146]

number

[0147] (3) Apparent power The apparent power (S) is calculated based on the phase voltage effective value (Vrms) and the phase current effective value (Irms). Specifically, the apparent power (S) can be expressed as follows:

[0148]

number

[0149] (4) Active power The active power (P) is calculated based on the phase voltage effective value (Vrms), the phase current effective value (Irms), and the phase difference (φ1) between the phase voltage and the phase current. The phase difference (φ1) between the phase voltage and the phase current is the phase difference between one phase voltage (e.g., U-phase voltage (Vu)) and one phase current (e.g., U-phase current (iu)), and is calculated based on the phase (ωi) of the phase current and the phase (ωv) of the phase voltage. Specifically, the active power (P) can be expressed as follows:

[0150]

number

[0151] (5) Reactive power The reactive power (Q) is calculated based on the phase voltage effective value (Vrms), the phase current effective value (Irms), and the phase difference (φ1) between the phase voltage and the phase current. The phase difference (φ1) between the phase voltage and the phase current is, for example, the phase difference between the U-phase voltage (Vu) and the U-phase current (iu), and is calculated based on the phase (ωi) of the phase current and the phase (ωv) of the phase voltage. Specifically, the reactive power (Q) can be expressed as follows:

[0152]

number

[0153] [4. Current obtained by coordinate transformation of phase current with the phase of the phase current] The currents (iγ, iδ) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) using the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (60) can be expressed by the following equations.

[0154]

number

[0155] [5. Voltage obtained by coordinate transformation of phase voltage with the phase of the phase voltage] The voltages (Vγ, Vδ) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) using the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (60) can be expressed by the following equations:

[0156]

number

[0157] [6. Current obtained by coordinate transformation of phase current with the phase voltage] The currents (iζ, iη) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) using the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (60) can be expressed by the following equations:

[0158]

number

[0159] [7. Voltage obtained by coordinate transformation of phase voltage with the phase current] The voltages (Vζ, Vη) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) using the phases (ωi·t) of the phase currents (iu, iv, iw) of the motor (60) can be expressed by the following equations:

[0160]

number

[0161] [6. Magnitude of dq-axis magnetic flux and armature interlinkage magnetic flux vector] The dq-axis magnetic flux (λd, λq) coordinate-transformed to match the armature flux linkage caused by the permanent magnet, and the magnitude λ0 of the armature flux linkage vector, which is the composite of the armature flux linkage of the permanent magnet and the armature reaction, can be expressed as follows: In the following equation, "Ld" is the d-axis inductance, and "Lq" is the q-axis inductance.

[0162]

number

[0163] [7. Other examples of DC signals] The DC signal may be a DC signal obtained by performing a three-phase to two-phase conversion on the phase current, phase voltage, line current, or line voltage of the motor (60) and then performing a rotational coordinate conversion. For example, the DC signal may be a d-axis current and a q-axis current obtained by performing a rotational coordinate conversion on the α-axis current and the β-axis current obtained by performing a three-phase to two-phase conversion on the phase current of the motor (60) at an angle based on the orientation of the magnetic poles of the rotor of the motor (60). The DC signal may be an M-axis current and a T-axis current obtained by performing a rotational coordinate conversion on the α-axis current and the β-axis current at an angle based on the orientation of the primary magnetic flux of the rotor of the motor (60).

[0164] The DC signal may also be the power input to the converter (21) of the motor drive device (20), the power output from the converter (21), the power output from the DC unit (22), the current flowing between the converter (21) and the DC unit (22), the current flowing between the DC unit (22) and the inverter (23), etc.

[0165] [Example of AC signal] Examples of AC signals include "phase currents (iu, iv, iw) of the motor (60)," "phase voltages (Vu, Vv, Vw) of the motor (60)," and "flux linkages of each phase (Ψfu, Ψfv, Ψfw)."

[0166] The interlinkage magnetic flux of each phase (Ψfu, Ψfv, Ψfw) can be expressed as follows:

[0167]

number

[0168] Another example of the AC signal is a current or voltage flux linkage of fixed coordinates obtained by three-phase to two-phase conversion of the AC signal.

[0169] The AC signal may be a line current, a line voltage, or the like of the motor (60). The AC signal may be a two-phase AC current (e.g., an α-axis current and a β-axis current) or a two-phase AC voltage obtained by three-phase to two-phase conversion of a phase current, a phase voltage, a line current, or a line voltage. The AC current may be a current flowing between a commercial power supply system (specifically, the AC power supply (5)) and the converter (21) of the motor drive device (20).

[0170] (Specific example of estimation process) Next, specific examples of estimation processing will be described. Examples of estimation processing include the following four estimation processing (first to fourth estimation processing). Below, an example will be described in which estimation processing is performed based on the amplitude of a specific frequency component. In the following description, the "specific frequency component" means the "amplitude value of the specific frequency component."

[0171] In the following description, a value indicating the magnitude of a change over time in a specific frequency component included in a physical quantity correlated with the state of the compressor (50) will be referred to as an “index value.” For example, in the estimation process, the control unit (31) derives an index value at each predetermined processing cycle and, depending on the result of comparison between the index value and a threshold value, estimates whether the state of the compressor (50) is “a state in which a specific frequency component changes suddenly.”

[0172] [First estimation process] First, the first estimation process will be described with reference to Fig. 9. The index value in the first estimation process is a ratio value obtained by dividing the "first filter value (F1) indicating the specific frequency component processed by the first filter" by the "second filter value (F2) indicating the specific frequency component determined by the second filter." The time constant of the second filter is larger than the time constant of the first filter.

[0173] If the time constant of the first filter is too large, there is a risk that a change over time (a change over 20 to 30 seconds) in a specific frequency component that appears during an abnormality (for example, when the sealing of the compression chamber (68) is broken due to lubricating oil) may not be detected. Therefore, for example, the time constant of the first filter may be set to "less than 21.556 seconds," or specifically, to "3.59 seconds."

[0174] Furthermore, if the time constant of the second filter is too small, it will approach the time constant of the first filter, and the change in the index value (the above-mentioned ratio value) during an abnormality will be small. Conversely, if the time constant of the second filter is too large, the influence of changes over time in the rotation speed, pressure, and temperature of the motor (60) of the compressor (50) may become significant. Therefore, for example, the time constant of the second filter may be set to "21.556 seconds or more and 215.56 seconds or less," specifically, "64.67 seconds."

[0175] In the first estimation process, the control unit (31) determines whether or not the index value in the first estimation process (in this example, a ratio value obtained by dividing the “first filter value (F1)” by the “second filter value (F2)”) is below a predetermined threshold value (in this example, a threshold value for detecting a sudden drop in the specific frequency component). If the index value is below the threshold value, the control unit (31) estimates that the state of the compressor (50) is “a state in which the specific frequency component changes suddenly (in this example, a sudden drop).” On the other hand, if the index value is not below the threshold value, the control unit (31) estimates that the state of the compressor (50) is not “a state in which the specific frequency component changes suddenly (in this example, a sudden drop).”

[0176] In the first estimation process, the control unit (31) may estimate whether the state of the compressor (50) is “a state in which the specific frequency component increases sharply.” In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component increases sharply” when the index value exceeds a predetermined threshold value (a threshold value for detecting a sharp increase in the specific frequency component).

[0177] Furthermore, the index value in the first estimation process may be a difference value obtained by subtracting the "second filter value (F2)" from the "first filter value (F1)".

[0178] Alternatively, the index value in the first estimation process may be a ratio value obtained by dividing the “second filter value (F2)” by the “first filter value (F1).” In this case, for example, when the index value in the first estimation process exceeds a predetermined threshold value (a threshold value for detecting a sudden drop in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component suddenly changes (specifically, suddenly drops).”

[0179] Alternatively, the index value in the first estimation process may be a difference value obtained by subtracting the “first filter value (F1)” from the “second filter value (F2).” In this case, for example, when the index value in the first estimation process exceeds a predetermined threshold value (a threshold value for detecting a sudden drop in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component is suddenly changing (specifically, suddenly dropping).”

[0180] [Second estimation process] Next, the second estimation process will be described with reference to FIG. 10. The index value in the second estimation process is calculated based on the first time (t k ) and the first time average value (A1), which is the average value of a specific frequency component within a predetermined period (Ta) ending at the first time (t k ) a second time (t k-1 ) and a second time average value (A2), which is the average value of the specific frequency component within a predetermined period (Ta) ending at

[0181] If the predetermined time (Ta) is too long, a change over time (a change over time of 20 to 30 seconds) in a specific frequency component that appears when an abnormality occurs (for example, when the sealing of the compression chamber (68) is broken by lubricating oil) may not be detected. Therefore, the predetermined time (Ta) may be set to, for example, "less than 60 seconds," or specifically, "5 seconds."

[0182] Furthermore, if the time (T) is too short, the change in the index value (the difference value) during an abnormality will be small. Conversely, if the time (T) is too long, the influence of changes over time in the rotation speed, pressure, and temperature of the motor (60) of the compressor (50) may become significant. Therefore, the time (T) may be set to, for example, "60 seconds or more and 600 seconds or less," specifically, "60 seconds."

[0183] In the second estimation process, the control unit (31) determines whether or not the index value in the second estimation process (in this example, a difference value obtained by subtracting the “second time average value (A2)” from the “first time average value (A1)”) exceeds a predetermined threshold value (in this example, a threshold value for detecting a sudden increase in the specific frequency component). If the index value exceeds the threshold value, the control unit (31) estimates that the state of the compressor (50) is “a state in which the specific frequency component changes suddenly (in this example, a sudden increase).” On the other hand, if the index value does not exceed the threshold value, the control unit (31) estimates that the state of the compressor (50) is not “a state in which the specific frequency component changes suddenly (in this example, a sudden increase).”

[0184] In the second estimation process, the control unit (31) may estimate whether the state of the compressor (50) is “a state in which the specific frequency component drops sharply.” In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component drops sharply” when the index value is below a predetermined threshold value (a threshold value for detecting a sharp drop in the specific frequency component).

[0185] Furthermore, the index value in the second estimation process may be a ratio value obtained by dividing the "first time average value (A1)" by the "second time average value (A2)".

[0186] Alternatively, the index value in the second estimation process may be a difference value obtained by subtracting the “first time average value (A1)” from the “second time average value (A2).” In this case, for example, when the index value in the second estimation process is below a predetermined threshold value (a threshold value for detecting a sudden increase in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component suddenly changes (specifically, suddenly increases).”

[0187] Alternatively, the index value in the second estimation process may be a ratio value obtained by dividing the “second time average value (A2)” by the “first time average value (A1).” In this case, for example, when the index value in the second estimation process is below a predetermined threshold value (a threshold value for detecting a sudden increase in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component suddenly changes (specifically, suddenly increases).”

[0188] [Third estimation process] Next, the third estimation process will be described with reference to Fig. 11 and Fig. 12. The index value in the third estimation process is calculated based on the "predetermined time (t i ) (for example, the current time) ends at a first time period (T1), and the first moving average value (MA1) is calculated as a moving average value of a specific frequency component within the first time period (T1) ending at a predetermined time (t i The ratio is obtained by dividing the first period (T1) by the second moving average value (MA2), which is the moving average value of the specific frequency component within the second period (T2) ending at T1. The second period (T2) is longer than the first period (T1).

[0189] If the first period (T1) is too long, there is a risk that a change over time (a change over time of 20 to 30 seconds) in the specific frequency component that appears in an abnormal state (for example, when the sealing of the compression chamber (68) is broken by the lubricating oil) may not be detected. Therefore, the first period (T1) may be set to, for example, "less than 60 seconds," or specifically, "10 seconds."

[0190] If the second period (T2) is too short, the change in the index value (the above-mentioned ratio) during an abnormality will be small. Conversely, if the second period (T2) is too long, the influence of changes over time in the rotation speed, pressure, and temperature of the motor (60) of the compressor (50) may become significant. Therefore, the second period (T2) may be set to, for example, "60 seconds or more and 600 seconds or less," specifically, "180 seconds."

[0191] In the third estimation process, the control unit (31) determines whether or not the index value in the third estimation process (in this example, a ratio value obtained by dividing the "first moving average value (MA1)" by the "second moving average value (MA2)") exceeds a predetermined threshold value (in this example, a threshold value for detecting a sudden increase in the specific frequency component). If the index value exceeds the threshold value, the control unit (31) estimates that the state of the compressor (50) is "a state in which the specific frequency component changes suddenly (in this example, a sudden increase)." On the other hand, if the index value does not exceed the threshold value, the control unit (31) estimates that the state of the compressor (50) is not "a state in which the specific frequency component changes suddenly (in this example, a sudden increase)."

[0192] In the third estimation process, the control unit (31) may estimate whether the state of the compressor (50) is “a state in which the specific frequency component drops sharply.” In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component drops sharply” when the index value is below a predetermined threshold value (a threshold value for detecting a sharp drop in the specific frequency component).

[0193] The index value in the third estimation process may be a difference value obtained by subtracting the "second moving average value (MA2)" from the "first moving average value (MA1)".

[0194] Alternatively, the index value in the third estimation process may be a ratio value obtained by dividing the “second moving average value (MA2)” by the “first moving average value (MA1).” In this case, for example, when the index value in the third estimation process is below a predetermined threshold value (a threshold value for detecting a sudden increase in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component suddenly changes (specifically, suddenly increases).”

[0195] Alternatively, the index value in the third estimation process may be a difference value obtained by subtracting the “first moving average value (MA1)” from the “second moving average value (MA2).” In this case, for example, when the index value in the third estimation process is below a predetermined threshold value (a threshold value for detecting a sudden increase in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component suddenly changes (specifically, suddenly increases).”

[0196] [Fourth estimation process] Next, the fourth estimation process will be described with reference to FIG. 13. The index value in the fourth estimation process is calculated based on the "predetermined time (t i ) (for example, the current time) is defined as the instantaneous value (X) of a specific frequency component at a predetermined time (t i The ratio is calculated by dividing the average value (AA) of the specific frequency component within a predetermined period (Tb) ending at the specified frequency (Tb).

[0197] If the predetermined period (Tb) is too short, the change in the index value (the difference value) during an abnormality will be small. Conversely, if the predetermined period (Tb) is too long, the influence of changes over time in the rotation speed, pressure, and temperature of the motor (60) of the compressor (50) may become significant. Therefore, the predetermined period (Tb) may be set to, for example, "60 seconds or more and 600 seconds or less," specifically, "180 seconds."

[0198] In the fourth estimation process, the control unit (31) determines whether or not the index value in the fourth estimation process (in this example, a ratio value obtained by dividing the "instantaneous value (X)" by the "average value (AA)") is below a predetermined threshold value (in this example, a threshold value for detecting a sudden drop in the specific frequency component). If the index value is below the threshold value, the control unit (31) estimates that the state of the compressor (50) is "a state in which the specific frequency component changes suddenly (in this example, a sudden drop)." On the other hand, if the index value is not below the threshold value, the control unit (31) estimates that the state of the compressor (50) is not "a state in which the specific frequency component changes suddenly (in this example, a sudden drop)."

[0199] In the fourth estimation process, the control unit (31) may estimate whether the state of the compressor (50) is “a state in which the specific frequency component increases sharply.” In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component increases sharply” when the index value exceeds a predetermined threshold value (a threshold value for detecting a sharp increase in the specific frequency component).

[0200] Furthermore, the index value in the fourth estimation process may be a difference value obtained by subtracting the "average value (AA)" from the "instantaneous value (X)."

[0201] Alternatively, the index value in the fourth estimation process may be a ratio value obtained by dividing the “average value (AA)” by the “instantaneous value (X).” In this case, for example, when the index value in the fourth estimation process exceeds a predetermined threshold value (a threshold value for detecting a sudden drop in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is “a state in which the specific frequency component suddenly changes (specifically, suddenly drops).”

[0202] Alternatively, the index value in the fourth estimation process may be a difference value obtained by subtracting the instantaneous value (X) from the average value (AA). In this case, for example, when the index value in the fourth estimation process exceeds a predetermined threshold value (a threshold value for detecting a sudden drop in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state in which the specific frequency component is suddenly changing (specifically, suddenly dropping).

[0203] (Refrigeration system) 14 illustrates the configuration of a refrigeration system (RR). The refrigeration system (RR) includes a refrigerant circuit (RR1) filled with a refrigerant, a motor drive device (20), and a control device (30).

[0204] The refrigerant circuit (RR1) includes a compressor (50), a radiator (RR5), a pressure reduction mechanism (RR6), and an evaporator (RR7). In this example, the pressure reduction mechanism (RR6) is an expansion valve. The refrigerant circuit (RR1) performs a vapor compression refrigeration cycle.

[0205] The compressor (50) has a compression mechanism (65) and a motor (60). The compression mechanism (65) is connected to the motor (60) by a drive shaft. The motor (60) drives the drive shaft to rotate, thereby driving the compression mechanism (65). The motor drive device (20) drives the motor (60).

[0206] In the refrigeration cycle, the refrigerant flowing out of the compressor (50) dissipates heat in the radiator (RR5). The refrigerant flowing out of the radiator (RR5) is decompressed in the pressure reducing mechanism (RR6) and evaporated in the evaporator (RR7). The refrigerant flowing out of the evaporator (RR7) then flows into the compressor (50).

[0207] In this example, the refrigeration system (RR) is an air conditioner. The air conditioner may be a dedicated cooling unit or a dedicated heating unit. The air conditioner may also be an air conditioner that switches between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., a four-way switching valve) that switches the refrigerant circulation direction. The refrigeration system (RR) may also be a water heater, a chiller unit, a cooling device that cools the air inside a storage unit, etc. The cooling device cools the air inside a refrigerator, freezer, container, etc.

[0208] (Findings gained through experiments) Next, with reference to FIGS. 15 and 16, an experiment conducted by the inventors of the present invention and findings obtained from the experiment will be described.

[0209] As shown in FIG. 15, in the experiment, the "amplitude value of a specific frequency component" included in a physical quantity (in this example, the current vector amplitude (Ia)) obtained within a 10-second period was calculated every second. The absolute value of the difference between the value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2) and 1 was used as the "index value." The index value can be expressed as "|1-(MA1 / MB2)|." The above index value can be considered a modified example of the index value in the third estimation process.

[0210] The first moving average value (MA1) is the average value of 10 amplitude values ​​calculated within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value is calculated. The second moving average value (MA2) is the average value of 180 amplitude values ​​calculated within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value is calculated. For example, the first period (T1) and the second period (T2) can be illustrated as shown in FIG. 12.

[0211] In the experiment, the compressor (50) was set to a predetermined "steady state." The steady state of the compressor (50) is not a predetermined state (a state in which a specific frequency component changes suddenly), but a state in which the compressor (50) operates under predetermined operating conditions (steady operating conditions). For example, the steady state of the compressor (50) is a state in which all of the following conditions are satisfied:

[0212] (1) The suction port (101a) of the oil supply path (100) is immersed in the lubricating oil accumulated in the oil reservoir (54). (2) The gaseous working fluid is sucked into the compressor (50). (3) The rotational frequency of the motor (60) of the compressor (50) is in a steady state. (4) The pressure of the working fluid discharged from the compressor (50) is in a steady state. (5) The pressure of the working fluid sucked into the compressor (50) is in a steady state. (6) The temperature of the working fluid discharged from the compressor (50) is in a steady state. (7) The temperature of the working fluid sucked into the compressor (50) is in a steady state. The steady state may be determined based on the application of the compressor (50).

[0213] As shown in FIG. 16, the index value observed when the compressor (50) was in a steady state was a value below 0.1. When the compressor (50) went from the steady state to a predetermined state (a state in which a specific frequency component changes suddenly), the index value exceeded 0.1 and rose to a maximum value (for example, about 3.5). Even when the compressor (50) was in a steady state, the index value fluctuated slightly. When the index value included in the 10-minute measurement period was observed, a peak (maximum value) of the slight fluctuation in the index value was observed.

[0214] In addition, in order to verify the influence of individual differences in the compressor (50), the compressor (50) provided in the refrigeration system (RR) was replaced with another compressor (50) (compressor (50) of the same model), and the above index value was observed repeatedly. As a result, the index value when the compressor (50) was in a steady state was below "0.1" regardless of the individual differences in the compressor (50).

[0215] Through the above experiments, the inventors of the present application have obtained the following findings: In the following, a condition will be referred to as a "verification condition" where an amplitude value of a specific frequency component included in a physical quantity obtained within a 10-second period is derived every second, the average of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value is derived is defined as a "first moving average value (MA1)," the average of 180 amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value is derived is defined as a "second moving average value (MA2)," and the absolute value of the difference between 1 and a value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2) is defined as an "index value."

[0216] The inventors of the present application have found that, under the above verification conditions, by setting the threshold value for the index value to “a value that is 1.1 times or more the maximum index value obtained in a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state” or to “0.1,” it is possible to estimate that the state of the compressor (50) is in a predetermined state (a state in which a specific frequency component changes suddenly) when the index value exceeds the threshold value.

[0217] By setting the threshold value for the index value in each of the first to fourth estimation processes as follows, it is possible to perform countermeasure processing at the same timing as the countermeasure processing when the threshold for the above index value (the absolute value of the difference between 1 and the value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2)) is set to "0.1." Hereinafter, the index value that is "the absolute value of the difference between 1 and the value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2)" will be referred to as the "reference index value."

[0218] [Threshold value for index value in first estimation process] If the index value is a ratio obtained by dividing the first filter value (F1) by the second filter value (F2), the threshold is set to a range of 0.89 to 1.11. If the index value deviates from the above range, the reference index value will exceed 0.1.

[0219] Also, when the index value is "the absolute value of the difference between 1 and the ratio value obtained by dividing the first filter value (F1) by the second filter value (F2)," the threshold is set to "0.11." If this index value exceeds the threshold, the reference index value will exceed "0.1."

[0220] [Threshold value for index value in second estimation process] If the index value is the difference value obtained by subtracting the second time average value (A2) from the first time average value (A1), the threshold is set to the range from -0.25 to +0.25. If this index value deviates from the above range, the reference index value will exceed 0.1.

[0221] [Threshold value for index value in third estimation process] If the index value is a ratio obtained by dividing the first moving average value (MA1) by the second moving average value (MA2), the threshold is set to a range of 0.9 to 1.1. If the index value deviates from the above range, the reference index value will exceed 0.1.

[0222] [Threshold value for index value in fourth estimation process] When the index value is a ratio obtained by dividing the instantaneous value (X) of a specific frequency component by the average value (AA) of the specific frequency component within a predetermined period (Tb), the threshold is set to a range of 0.69 to 1.31. If the index value deviates from the above range, the reference index value will exceed 0.1.

[0223] Also, when the index value is "the absolute value of the difference between 1 and a ratio value obtained by dividing the instantaneous value (X) of a specific frequency component by the average value (AA) of the specific frequency component within a predetermined period (Tb)," the threshold is set to "0.31." If this index value exceeds the threshold, the reference index value will exceed "0.1."

[0224] (Other embodiments) In the above description, a signal indicating a physical quantity correlated with the voltage or current of the motor (60) has been given as an example of a physical quantity correlated with the state of the motor (60). However, this is not limiting. For example, the physical quantity may be a signal indicating vibration of the motor (60) or a signal indicating sound of the motor (60). The signal indicating vibration of the motor (60) may be acquired by a vibration sensor (not shown) provided in the compressor (50) or the appliance (1). The signal indicating sound of the motor (60) may be acquired by a microphone (not shown) provided in the compressor (50) or the appliance (1). The sound may be sound within the audible range or sound outside the audible range (ultrasonic). Thus, the physical quantity may be any of the rotational frequency of the motor (60), the voltage applied to the motor (60), the current flowing through the motor (60), the vibration of the compressor (50), the sound of the compressor (50), and sound around the compressor (50).

[0225] In addition, in the above description, the control unit (31) may be configured to perform the estimation process using an algorithm (an algorithm for estimating a state based on a change in a signal) constructed by a neural network or machine learning.

[0226] In the above description, the control unit 31 may be realized by one processor or by multiple processors. The control unit 31 may also be realized by multiple arithmetic processing units (computers) that communicate with each other via a communication network.

[0227] In the above description, the compressor (50) is a "scroll compressor," but the present invention is not limited to this. For example, the compressor (50) may be a swing compressor in which the piston and the blade are integrally formed, a rotary compressor in which the piston and the blade are formed separately, or another type of rotary compressor.

[0228] The compressor (50) may also be a two-cylinder compressor having two compression chambers (a swing compressor or a rotary compressor).

[0229] As shown in FIG. 17, the torque pulsation period (pulsation period during normal operation) of a two-cylinder compressor corresponds to half the rotation period of the motor (60). Furthermore, in a two-cylinder compressor, when liquid compression occurs, a sudden change in the torque of the compressor occurs at a period corresponding to half the rotation period of the motor (60). Therefore, in a two-cylinder compressor, when liquid compression occurs, the second-order component of the torque of the compressor (50) suddenly changes (specifically, rises sharply), and as a result, the second-order component of the current vector amplitude (Ia) suddenly changes (specifically, rises sharply). The "second-order component" refers to a frequency component having a frequency twice the mechanical angular frequency of the motor (60).

[0230] When the compressor (50) is a “two-cylinder compressor,” the “specific frequency component processed in the estimation process” may be a “second-order component.” This makes it possible to estimate whether the state of the compressor (50) is a “liquid compression state.”

[0231] In the above description, the various sensors may be contact-type sensors or non-contact-type sensors. A contact-type sensor may be attached to the casing (51) of the compressor (50), or to a pipe or an electric wire arranged near the compressor (50). A non-contact-type sensor may be attached to a location near the casing (51) of the compressor (50), a location near a pipe or an electric wire arranged near the compressor (50), or a location near the equipment (1) in which the compressor (50) is installed.

[0232] In the above description, the detector for detecting information for obtaining a physical quantity correlated with the state of the compressor (50) may be a single sensor or a combination of a plurality of sensors.

[0233] In the above description, the change process may be a process for changing the operating conditions of the system including the compressor (50). The change process may change not only the operating conditions of the motor (60) but also the operating conditions of other components other than the motor (60) included in the system including the compressor (50). Examples of the change processing include a processing for stopping the motor (60), a processing for accelerating the motor (60), a processing for decelerating the motor (60), a processing for reducing the current flowing through the motor (60), a processing for increasing the opening of an expansion valve (motor-operated valve) constituting the pressure reducing mechanism (RR6), a processing for reducing the opening of an expansion valve (motor-operated valve) constituting the pressure reducing mechanism (RR6), a processing for increasing the pressure of the working fluid discharged from the compressor (50), a processing for decreasing the pressure of the working fluid discharged from the compressor (50), a processing for increasing the temperature of the working fluid discharged from the compressor (50), a processing for decreasing the temperature of the working fluid discharged from the compressor (50), a processing for returning the lubricating oil flowing through the fluid flow path together with the working fluid to the compressor (50), a processing for increasing the rotation speed of a fan (not shown) that conveys air to the radiator (RR5) or the evaporator (RR7), and a processing for decreasing the rotation speed of a fan that conveys air to the radiator (RR5) or the evaporator (RR7).

[0234] Although the embodiments and modifications have been described, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above-described embodiments, modifications, and other embodiments may be combined or substituted as appropriate.

[0235] (Summary of the embodiment) To summarize the above description, the control device of the embodiment relates to a control device that controls a system including a compressor (50) having a motor (60) and a compression mechanism (65). The control device includes a control unit (31). The control unit (31) performs a countermeasure process including at least one of an output process that outputs information indicating that the compressor (50) is in a predetermined state and a change process that changes an operating condition of the system when a relationship between an index value indicating the magnitude of a temporal change in a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and a predetermined threshold value satisfies a predetermined relationship.

[0236] As a result of intensive research, the inventors of the present application have found that there exists a "state in which a specific frequency component contained in a physical quantity correlated with the state of the compressor (50) changes suddenly" in the state of the compressor (50) having a motor (60) and a compression mechanism (65). Furthermore, the inventors have found that such a state (the state of the compressor (50) in which the specific frequency component changes suddenly) can be estimated based on the magnitude of the temporal change in the specific frequency component contained in the physical quantity.

[0237] In the above configuration, when the index value indicating the magnitude of the temporal change of a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and the predetermined threshold value have a predetermined relationship, a countermeasure is performed. This makes it possible to appropriately perform a countermeasure when the state of the compressor (50) is in a predetermined state (a state in which the specific frequency component changes suddenly).

[0238] The control unit (31) may be configured to perform a corrective action when the index value exceeds the threshold value under the condition that the amplitude value of a specific frequency component included in a physical quantity obtained within a 10-second period is derived every second, where the index value is defined as “the absolute value of the difference between 1 and a value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2),” the first moving average value (MA1) is defined as “the average value of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value is derived,” the second moving average value (MA2) is defined as “the average value of 180 amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value is derived,” and the threshold value is defined as “a value that is 1.1 times or more the maximum index value obtained within a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state.”

[0239] As a result of extensive research, the inventors of the present application have found that by setting the threshold value for the index value to “a value that is 1.1 times or more the maximum index value obtained in a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state,” it is possible to estimate that the state of the compressor (50) is in a predetermined state (a state in which a specific frequency component changes suddenly) when the index value exceeds the threshold value.

[0240] In the above configuration, by taking corrective action when the index value exceeds the threshold value, it is possible to appropriately take action to deal with the case where the compressor (50) is in a predetermined state (a state in which a specific frequency component changes suddenly).

[0241] Furthermore, the control unit (31) may be configured to, under a condition where an amplitude value of a specific frequency component included in a physical quantity obtained within a 10-second period is derived every second, set the index value to “the absolute value of the difference between 1 and a value obtained by dividing a first moving average value (MA1) by a second moving average value (MA2),” set the first moving average value (MA1) to “the average value of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value is derived,” set the second moving average value (MA2) to “the average value of 180 amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value is derived,” and set the threshold to “0.1,” and perform a corrective action if the index value exceeds the threshold.

[0242] As a result of extensive research, the inventors of the present application have found that by setting a threshold value for the index value to “0.1,” it is possible to estimate that the state of the compressor (50) is a predetermined state (a state in which a specific frequency component changes suddenly) when the index value exceeds the threshold value.

[0243] In the above configuration, by taking corrective action when the index value exceeds the threshold value, it is possible to appropriately take action to deal with the case where the compressor (50) is in a predetermined state (a state in which a specific frequency component changes suddenly).

[0244] The compression mechanism (65) may have a compression chamber (68) for compressing the working fluid. The compression chamber (68) may be sealed with lubricating oil. The predetermined state may be a state in which the sealing ability of the compression chamber (68) provided by the lubricating oil has been broken.

[0245] As a result of extensive research, the inventors of the present application have discovered the following phenomenon: "When the sealing performance of the compression chamber (68) by the lubricating oil in the compressor (50) is broken, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) suddenly changes."

[0246] In the above-described configuration, it is possible to appropriately perform a process for dealing with the case where the compressor (50) is in a state where the sealing performance of the compression chamber (68) by the lubricating oil has been broken down.

[0247] The compression mechanism (65) may have a compression chamber (68) for compressing the working fluid. The compressor (50) may have an oil reservoir (54) for storing lubricating oil and an oil supply path (100) for supplying the lubricating oil stored in the oil reservoir (54) to the compression chamber (68). The oil supply path (100) may have a suction port (101a), and the suction port (101a) may be immersed in the lubricating oil stored in the oil reservoir (54), thereby enabling the lubricating oil drawn through the suction port (101a) to be supplied to the compression chamber (68). The compression chamber (68) may be sealed with the lubricating oil. The predetermined state may be a state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil stored in the oil reservoir (54).

[0248] As a result of extensive research, the inventors of the present application have discovered the following phenomenon: "When the suction port (101a) of the oil supply path (100) of the compressor (50) is no longer immersed in the lubricating oil accumulated in the oil reservoir (54), the sealing performance of the compression chamber (68) by the lubricating oil is broken down, and as a result, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) suddenly changes."

[0249] In the above configuration, appropriate processing can be performed to deal with the situation where the compressor (50) is in a state where the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).

[0250] The predetermined state may also be a liquid compression state in which the liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65).

[0251] As a result of extensive research, the inventors of the present application have discovered the following phenomenon: "When a liquid working fluid is sucked into the compression mechanism (65) in the compressor (50) and compressed in the compression mechanism (65), a specific frequency component included in a physical quantity correlated with the state of the compressor (50) suddenly changes."

[0252] In the above configuration, it is possible to appropriately perform processing to deal with the case where the compressor (50) is in a “liquid compression state in which a liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65).”

[0253] Furthermore, a control method according to an embodiment relates to a control method for controlling a system including a compressor (50) having a motor (60) and a compression mechanism (65). The control method includes an acquisition step and a countermeasure step. In the acquisition step, a physical quantity correlated with a state of the compressor (50) is acquired. In the countermeasure step, when an index value indicating the magnitude of a temporal change in a specific frequency component included in the physical quantity acquired in the acquisition step satisfies a predetermined relationship with a predetermined threshold, at least one of an output step of outputting information indicating that the state of the compressor (50) is a predetermined state and a change step of changing an operating condition of the system is performed.

[0254] In the above method, a countermeasure step is performed when a relationship between an index value indicating the magnitude of a temporal change in a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and a predetermined threshold value satisfies a predetermined relationship, thereby making it possible to appropriately perform processing to counter the case where the state of the compressor (50) is in a predetermined state (a state in which the specific frequency component changes suddenly). [Industrial Applicability]

[0255] As described above, the present disclosure is useful as a control technique. [Explanation of symbols]

[0256] 1 equipment 5 Power supply 10 Drive System 20 Motor drive unit 21 Converter 22 DC section 23 Inverter (conversion unit) 30 Control device (state estimation device) 31 Control Unit 41 Phase current detection unit 42 Electrical angle frequency detector 50 Compressor 54 Oil reservoir 60 motor 65 Compression mechanism 68 Compression Chamber 100 Refueling Route 101a Intake port RR Refrigeration System RR1 refrigerant circuit

Claims

1. A control device for controlling a system including a compressor (50) having a motor (60) and a compression mechanism (65), comprising: a control unit (31) that performs, when a relationship between an index value indicating a magnitude of a temporal change in a specific frequency component included in a physical quantity correlated with a state of the compressor (50) and a predetermined threshold value satisfies a predetermined relationship, a countermeasure process including at least one of an output process that outputs information indicating that the state of the compressor (50) is a predetermined state and a change process that changes an operating condition of the system, Under a condition that the amplitude value of the specific frequency component included in the physical quantity obtained within a period of 10 seconds is derived every second, The index value is set to the absolute value of the difference between 1 and a value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2), The first moving average value (MA1) is set to an average value of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at a time (ti) at which the latest amplitude value is derived, The second moving average value (MA2) is set to an average value of 180 of the amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) at which the latest amplitude value is derived, When the threshold value is set to a value that is 1.1 times or more the maximum value of the index value obtained in a measurement period of 10 minutes under the condition that the compressor (50) is in a predetermined steady state, The control unit (31) performs the corrective action when the index value exceeds the threshold value. Control device.

2. A control device for controlling a system including a compressor (50) having a motor (60) and a compression mechanism (65), a control unit (31) that performs, when a relationship between an index value indicating a magnitude of a temporal change in a specific frequency component included in a physical quantity correlated with a state of the compressor (50) and a predetermined threshold value satisfies a predetermined relationship, a countermeasure process including at least one of an output process that outputs information indicating that the state of the compressor (50) is a predetermined state and a change process that changes an operating condition of the system, Under a condition that the amplitude value of the specific frequency component included in the physical quantity obtained within a period of 10 seconds is derived every second, The index value is set to the absolute value of the difference between 1 and a value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2), The first moving average value (MA1) is set to an average value of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at a time (ti) at which the latest amplitude value is derived, The second moving average value (MA2) is set to an average value of 180 of the amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) at which the latest amplitude value is derived, When the threshold value is set to 0.1, The control unit (31) performs the corrective action when the index value exceeds the threshold value. Control device.

3. 2. The control device of claim 1, The compression mechanism (65) has a compression chamber (68) for compressing a working fluid, The compression chamber (68) is sealed with lubricating oil, The predetermined state is a state in which the sealing performance of the lubricating oil in the compression chamber (68) is broken down. Control device.

4. 2. The control device of claim 1, The compression mechanism (65) has a compression chamber (68) for compressing a working fluid, The compressor (50) has an oil reservoir (54) in which lubricating oil is stored, and an oil supply path (100) for supplying the lubricating oil stored in the oil reservoir (54) to the compression chamber (68), The oil supply path (100) has a suction port (101a), and the suction port (101a) is immersed in the lubricating oil accumulated in the oil reservoir (54), thereby enabling the lubricating oil sucked through the suction port (101a) to be supplied to the compression chamber (68), The compression chamber (68) is sealed by the lubricating oil, The predetermined state is a state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54). Control device.

5. 2. The control device of claim 1, The predetermined state is a liquid compression state in which the liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65). Control device.

6. 2. The control device of claim 1, The physical quantity is any one of the rotation frequency of the motor (60), the voltage applied to the motor (60), the current flowing through the motor (60), the vibration of the compressor (50), the sound of the compressor (50), and the sound around the compressor (50). Control device.

7. 2. The control device of claim 1, The frequency of the specific frequency component is a frequency synchronized with the rotation frequency of the motor (60). Control device.

8. a refrigerant circuit (RR1) including a compressor (50) having a motor (60) and a compression mechanism (65); the control device (30), The control device (30) is a control device according to any one of claims 1 to 7. Refrigeration system.

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