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 technology.

Background Art

[0002] Patent Document 1 discloses a failure symptom detection device for an air conditioner including a compressor including a motor and a drive device that outputs a three-phase current to the motor. This failure 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 rotor of the motor. The abnormality detection unit detects an abnormality of 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

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the state of 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 rapidly. However, as in Patent Document 1, simply comparing the magnitude of the specific frequency component with a threshold value may make it difficult to appropriately perform processing for coping with the case where the state of the compressor is a predetermined state (a state in which the specific frequency component included in the physical quantity changes rapidly).

Means for Solving the Problems

[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 performs a coping process including at least one of an output process of outputting information indicating that the state of the compressor (50) is a predetermined state and a change process of changing the operating conditions of the system when a relationship between an index value indicating a magnitude of a temporal change of a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and a predetermined threshold value becomes a predetermined relationship. The control device includes a control unit (31).

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

[0007] In the first aspect, by performing a coping process when a relationship between an index value indicating a magnitude of a temporal change of a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and a predetermined threshold value becomes a predetermined relationship, it is possible to appropriately perform a process for coping with the case where the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly).

[0008] In a second aspect of the present disclosure, in the control device of the first aspect, under the 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 as 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. The first moving average value (MA1) is 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 was derived. The second moving average value (MA2) is 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 was 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 during a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state, the control unit (31) is a control device that performs the countermeasure process when the index value exceeds the threshold value.

[0009] As a result of intensive research, the inventor of the present application has found that by setting the threshold value for the above index value to "a value that is 1.1 times or more the maximum value of the index value obtained during a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state", when the above index value exceeds the above threshold value, it can be estimated that the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly).

[0010] In the second aspect, by performing a countermeasure process when the above index value exceeds the above threshold value, it is possible to appropriately perform a process for dealing with the case where the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly).

[0011] In a third aspect of the present disclosure, in the control device according to the first aspect, under the 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 the value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2) and 1. The first moving average value (MA1) is 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 was derived. The second moving average value (MA2) is the average value of 180 amplitude values derived within a second period (T2) of three minutes ending at the time (ti) when the latest amplitude value was derived. When the threshold value is 0.1, the control unit (31) is a control device that performs the countermeasure process when the index value exceeds the threshold value.

[0012] As a result of intensive research, the inventor of the present application has found that by setting the threshold value for the above index value to "0.1", when the above index value exceeds the above threshold value, it can be estimated that the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly).

[0013] In the third aspect, by performing a countermeasure process when the above index value exceeds the above threshold value, it is possible to appropriately perform a process for dealing with the case where the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly).

[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 the working fluid, the compression chamber (68) is sealed with lubricating oil, and the predetermined state is a state in which the sealing performance of the compression chamber (68) by the lubricating oil has failed.

[0015] As a result of intensive research, the inventor of the present application has found a phenomenon that "when the sealing performance of the compression chamber (68) by the lubricating oil fails in the compressor (50), the specific frequency component included in the physical quantity correlated with the state of the compressor (50) changes rapidly".

[0016] In the fourth aspect, it is possible to appropriately perform processing for dealing with the case where the state of the compressor (50) is "a state in which the sealing property of the compression chamber (68) by the lubricating oil has failed".

[0017] In a fifth aspect of the present disclosure, in any one of the control devices according to the first to third aspects, the compression mechanism (65) has a compression chamber (68) for compressing a working fluid, the compressor (50) has an oil sump portion (54) where lubricating oil accumulates, and an oil supply path (100) for supplying the lubricating oil accumulated in the oil sump portion (54) to the compression chamber (68). The oil supply path (100) has a suction port (101a). By immersing the suction port (101a) in the lubricating oil accumulated in the oil sump portion (54), it becomes possible to supply the lubricating oil sucked from the suction port (101a) 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 sump portion (54).

[0018] As a result of intensive research, the inventor of the present application has found that "when the suction port (101a) of the oil supply path (100) in the compressor (50) is no longer immersed in the lubricating oil accumulated in the oil sump portion (54), the sealing property of the compression chamber (68) by the lubricating oil fails, and as a result, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes rapidly".

[0019] In the fifth aspect, it is possible to appropriately perform processing for dealing with the case where 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 sump portion (54)".

[0020] In a sixth aspect of the present disclosure, in any one of the control devices according to the first to third aspects, 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 intensive research, the inventor of the present application has found that 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) changes abruptly.

[0022] In the sixth aspect, it is possible to appropriately perform processing for dealing with the case where the state of the compressor (50) is a "hydraulic 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 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 the sound around the compressor (50).

[0024] An eighth aspect of the present disclosure is a 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 rotational frequency of the motor (60).

[0025] A ninth aspect of the present disclosure relates to a refrigeration system, which includes a refrigerant circuit (RR1) including a compressor (50) having a motor (60) and a compression mechanism (65), and the control device (30), and the control device (30) is a control device according to any one 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 includes an acquisition step of acquiring a physical quantity correlated with the state of the compressor (50), and when a relationship between an index value indicating the magnitude of the temporal change of a specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold value becomes a predetermined relationship, an output step of outputting information indicating that the state of the compressor (50) is a predetermined state and a countermeasure step of performing at least one of a change step of changing the operating conditions of the system.

[0027] In the eleventh aspect, when the relationship between the index value indicating the magnitude of the temporal change of the specific frequency component included in the physical quantity correlated with the state of the compressor (50) and the predetermined threshold value becomes a predetermined relationship, the countermeasure step is performed, so that when the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly), appropriate processing for coping with the situation can be performed.

[0028] An eleventh aspect of the present disclosure is a control program for causing a computer to execute the control method of the tenth aspect.

Brief Description of the Drawings

[0029]

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Figure 17

DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions 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) has a compression mechanism (65) in addition to the motor (60). The compression mechanism (65) is driven by the motor (60), sucks in and compresses a working fluid, 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 IPM motor (Interior Permanent Magnet Motor). The drive system (10) is mounted on a 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 the electric 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) has a converter (21), a DC section (22), and an inverter (23).

[0034] The converter (21) rectifies the electric 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 constituted by a diode bridge circuit in which a plurality of rectifier diodes are connected in a bridge shape.

[0035] The DC section (22) generates DC power corresponding to the power source power supplied from the power source (5). In this example, the DC section (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 section (22) into output AC power (three-phase AC power) having a predetermined frequency and voltage by the switching operations of the plurality of switching elements. The inverter (23) is an example of a conversion section that converts the DC power generated by the DC section (22) into AC power by switching operations.

[0037] In this example, the inverter (23) has six bridge-connected switching elements and six freewheeling diodes respectively connected in antiparallel to 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 those three switching legs (specifically, the connection points between the upper-arm-side switching element and the lower-arm-side switching element) are respectively connected to the three windings (windings of the U-phase, V-phase, and W-phase) of the motor (60).

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

[0039] The phase current detection unit (41) detects three-phase 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 phase currents (iu, iv, iw), or may detect two of the three-phase phase currents (iu, iv, iw) and derive the remaining one phase current based on the detected two-phase phase currents. Further, the phase current detection unit (41) may derive the three-phase phase currents (iu, iv, iw) from the DC current detected by a shunt resistor (not shown) provided in the DC unit (22) and the switching pattern.

[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 and estimated sensorless.

[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 for estimating the state of the compressor (50). Further, the processing in the control device (30) (processing related to the control of the system including the compressor (50)) is an example of a control method for controlling the 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). Further, the control device (30) 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 part 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 that is electrically connected to the processor and stores a program for operating the processor. By executing the program by the processor, various functions of the control unit (31) are realized. Note that the control unit (31) is an example of a computer, the above program is an example of a state estimation program, and is also an example of a control program.

[0045] 〔Processes by the control unit〕 In this example, the control unit (31) performs an estimation process, a control process, and a countermeasure process.

[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 the temporal change of 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 of the specific frequency component is indicated by the amount of change per unit time of the specific frequency component. In the estimation process, it is estimated whether the state of the compressor (50) is a state in which the specific frequency component changes rapidly (specifically, rapidly increases or decreases). The estimation process will be described in detail later.

[0047] 〔Control process〕 In the control process, the control unit (31) controls the motor (60) by controlling the motor drive device (20). Specifically, the control unit (31) inputs target command values such as the command value of the electrical angular frequency (ω) of the motor (60), and detection signals of various sensors provided in the motor drive device (20). Then, based on the target command value, the detection signals of various sensors, etc., 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] 〔Countermeasure Processing〕 In this example, when the control unit (31) estimates in the estimation process that the state of the compressor (50) is a state where "a specific frequency component changes rapidly", it performs countermeasure processing. The countermeasure processing is processing for dealing with the state where "a specific frequency component of the compressor (50) changes rapidly", and includes at least one of an output process of outputting first information indicating that the state of the compressor (50) is a state where "a specific frequency component changes rapidly", and a change process of 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, combinations thereof, etc. The first output process is a process of causing a display device (not shown) provided in a remote controller or the like to display the first information by outputting the first information to the display device. The second output process is a process of causing a control unit (not shown) that controls the operation of the device (1) to perform an operation for dealing with an abnormal state by outputting the first information to the control unit. 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, combinations thereof, etc. The first change process is a process of stopping the motor (60). The second change process is a process of accelerating the motor (60). The third change process is a process of decelerating the motor (60).

[0051] 〔Details of the Compressor〕 As shown in FIG. 2, the compressor (50) is a hermetic scroll compressor. This compressor (50) includes a casing (51), a motor (60), a compression mechanism (65), a first support portion (80), and a second support portion (85). The motor (60), the compression mechanism (65), the first support portion (80), and the second support portion (85) are accommodated in the casing (51).

[0052] 〈Casing〉 The casing (51) is a cylindrical sealed container with both ends closed, and its axial direction is the vertical direction. In the internal space of the casing (51), the compression mechanism (65), the first support portion (80), the motor (60), and the second support portion (85) are arranged in order from top to bottom. Further, an oil reservoir portion (54) for storing lubricating oil (refrigeration machine oil) is formed at the bottom of the casing (51).

[0053] The casing (51) has an intake pipe (52) and a discharge pipe (53). The intake pipe (52) penetrates the top of the casing (51) and is connected to the compression mechanism (65), and guides a low-pressure working fluid from outside the compressor (50) to the compression mechanism (65). The discharge pipe (53) penetrates the body portion 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 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 such a 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 portion of the casing (51). The rotor (62) is arranged inside the stator (61). Further, a drive shaft (70) is inserted through the rotor (62).

[0055] 〈First Support Portion〉 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 a thick disk shape and is fixed to the casing (51). A crank chamber (81a) is formed in the central portion of the main body portion (81). The crank chamber (81a) is a cylindrical depression that opens to the front surface (the upper surface in FIG. 2) of the main body portion (81). The first bearing portion (82) is formed in a cylindrical shape that protrudes from the rear surface (the lower surface in FIG. 2) of the main body portion (81) and is disposed at the central portion of the main body portion (81). A through hole for inserting the drive shaft (70) is formed in the first bearing portion (82). A first bearing (91) described later is fitted into this through hole.

[0056] 〈Second Support Portion〉 The second support portion (85) includes a second bearing portion (86) and three leg portions (87). The second bearing portion (86) is formed in a thick cylindrical shape. A second bearing (92) described later is fitted into the second bearing portion (86). The leg portions (87) extend radially from the second bearing portion (86). The tip ends of the leg portions (87) of the second support portion (85) are fixed to the body portion of the casing (51).

[0057] 〈Compression Mechanism〉 The compression mechanism (65) is a scroll type fluid machine. The compression mechanism (65) has a fixed scroll (66) and a orbiting scroll (67). The wraps of the fixed scroll (66) and the orbiting scroll (67) mesh with each other to form a compression chamber (68).

[0058] The fixed scroll (66) includes a fixed-side mirror plate portion (66a), a fixed-side wrap (66b), and an outer peripheral wall portion (66c). The fixed-side mirror plate portion (66a) is a relatively thick flat plate-shaped portion located at the upper part of the fixed scroll (66). The fixed-side wrap (66b) is formed in a spiral wall shape and protrudes from the front surface (the lower surface in FIG. 2) of the fixed-side mirror plate portion (66a). The outer peripheral wall portion (66c) is formed so as to surround the outer peripheral side of the fixed-side wrap (66b) and protrudes from the front surface (the lower surface in FIG. 2) of the fixed-side mirror plate portion (66a). The outer peripheral wall portion (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 portion (66c), and an intake pipe (52) is inserted therein. A discharge port (dp) is formed in the fixed-side mirror plate portion (66a).

[0059] The swivel scroll (67) includes a swivel-side mirror plate portion (67a), a swivel-side wrap (67b), and a boss portion (67c). The swivel-side mirror plate portion (67a) is formed in a generally circular flat plate shape. The swivel-side wrap (67b) is formed in a spiral wall shape and protrudes from the front surface (the upper surface in FIG. 2) of the swivel-side mirror plate portion (67a). The boss portion (67c) is formed in a cylindrical shape protruding from the back surface (the lower surface in FIG. 2) of the swivel-side mirror plate portion (67a) and is disposed at the central portion of the swivel-side mirror plate portion (67a). A third bearing (93) described later is fitted into the boss portion (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 arranged in a posture where the eccentric shaft portion (72) is located above the main shaft portion (71).

[0061] In the main shaft portion (71), in order from one end to the other end, a main journal portion (71a), an intermediate shaft portion (71c), and an auxiliary journal portion (71b) are arranged. The main journal portion (71a), the intermediate shaft portion (71c), and the auxiliary journal portion (71b) are each formed in a cylindrical shape and arranged coaxially with each other. 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). Also, 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 inside 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 auxiliary journal portion (71b) is inserted inside 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 inside a rotor (62) of the motor (60) and is fixed to the rotor (62).

[0063] The eccentric shaft portion (72) is formed in a relatively short shaft shape and protrudes from an end face of the main journal portion (71a). The eccentric shaft portion (72) is located on the upper end side of 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 inside a third bearing (93) fitted in a boss portion (67c) of the swivel scroll (67) and is supported by the third bearing (93).

[0064] (Bearing) The first bearing (91), the second bearing (92), and the third bearing (93) are all formed in a cylindrical shape and are 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 first bearing (91) has the main journal portion (71a) of the drive shaft (70) inserted therein and supports the main journal portion (71a) 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 second bearing (92) has the sub-journal portion (71b) of the drive shaft (70) inserted therein and 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 swivel scroll (67). The third bearing (93) has the eccentric shaft portion (72) of the drive shaft (70) inserted therein and supports the eccentric shaft portion (72) of the drive shaft (70).

[0068] (Oil supply path) The compressor (50) is provided with an oil supply path (100). The oil supply path (100) is a path (passage) for supplying the lubricating oil (refrigeration machine oil) stored in the oil sump portion (54) formed at the bottom of the casing (51) to the sliding portions. The oil supply path (100) has a main oil supply path (101) and a sub oil supply path (102).

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

[0070] The sub-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, the gap between the fixed scroll (66) and the orbiting scroll (67)). One end of the sub-oil supply path (102) opens in the crank chamber (81a), and the other end is formed to open in the gap between the outer peripheral wall portion (66c) of the fixed scroll (66) and the orbiting side plate portion (67a) of the orbiting scroll (67). In the crank chamber (81a), the lubricating oil that is guided from the oil reservoir portion (54) to the sliding portion between the drive shaft (70) and the third bearing (93) via the main oil supply path (101), lubricates the sliding portion, and then the lubricating oil that has flowed out from the sliding portion is stored. The sub-oil supply path (102) guides the lubricating oil after lubricating the sliding portion between 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 such a configuration, the lubricating oil in the oil reservoir portion (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) via the suction port (101a) of the main oil supply path (101), flows through the main oil supply path (101), and is supplied to the 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 portion between the drive shaft (70) and the third bearing (93) lubricates the sliding portion between the drive shaft (70) and the third bearing (93), and then is stored in the crank chamber (81a). The lubricating oil stored in the crank chamber (81a) is supplied via the sub-oil supply path (102) to the compression chamber (68) of the compression mechanism (65) (specifically, the gap between the fixed scroll (66) and the orbiting scroll (67)) to seal the compression chamber (68).

[0072] [Findings obtained by the inventor of the present application] As a result of intensive research, the inventor of the present application has found that there is a state in the compressor (50) having a motor (60) and a compression mechanism (65) where "a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes abruptly".

[0073] Specifically, the inventor of the present application has found the phenomenon that "when the sealing property of the compression chamber (68) by lubricating oil fails in the compressor (50), a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes abruptly". In particular, the inventor of the present application has found the phenomenon that "when the suction port (101a) of the oil supply path (100) in the compressor (50) is no longer immersed in the lubricating oil accumulated in the oil reservoir portion (54), the sealing property of the compression chamber (68) by the lubricating oil fails, and as a result, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes abruptly".

[0074] The inventor of the present application has also found the phenomenon that "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) changes abruptly".

[0075] Furthermore, the inventor of the present application has found that the above state (the state of the compressor (50) where a specific frequency component changes abruptly) can be estimated based on the magnitude of the temporal change of the specific frequency component included in the physical quantity.

[0076] Hereinafter, the findings obtained by the inventor of the present application will be described in detail. In the following, the case where 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 the "frequency component having a frequency that is 1 times the mechanical angular frequency of the motor (60) (hereinafter referred to as the 'primary component')" will be described as an example. 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] 〔Sealing failure of compression chamber (68) due to lubricating oil〕 First, with reference to FIG. 2, the sealing failure 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 sump portion (54), the sealing performance of the compression chamber (68) by the lubricating oil fails, and the amplitude of the torque pulsation of the compressor (50) suddenly decreases. Specifically, the magnitude of the primary component of the rotational frequency of the motor (60) in the torque suddenly decreases. Therefore, when the sealing performance of the compression chamber (68) by the lubricating oil fails, the primary component of the rotational frequency of the motor (60) in the current vector amplitude (Ia) suddenly decreases.

[0078] Next, with reference to FIGS. 3 and 4, the change in the specific frequency component according to the change in the amount of oil accumulated in the oil sump portion (54) will be described. In the following description, "oil amount" refers to the amount of oil accumulated in the oil sump portion (54). "Normal oil amount" means a state in which the suction port (101a) of the oil supply path (100) is immersed in the lubricating oil accumulated in the oil sump portion (54). "Abnormal oil amount" means 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 sump portion (54).

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

[0080] As shown in FIGS. 3 and 4, the amplitude value of the specific frequency component during abnormal oil amount is smaller than the amplitude value of the specific frequency component during abnormal oil amount. Therefore, in order to discriminate between normal oil amount and abnormal oil amount, it is conceivable to compare the magnitude (amplitude value) of the specific frequency component with a threshold value. However, since it is necessary to consider the error included in the specific frequency component (such as sensor error, error due to the influence of pressure and temperature) in order to set the threshold value to be compared with the magnitude of the specific frequency component, it may be difficult to set the above threshold value appropriately.

[0081] For example, when the median value of a specific frequency component (e.g., the median value of an assumed change range) during normal oil quantity is "1.37 A" and the median value of the specific frequency component during abnormal oil quantity is "0.75 A", it is desirable to set the threshold value for discriminating between normal oil quantity and abnormal oil quantity between "0.75 A" and "1.37 A". However, the value of the specific frequency component during normal oil quantity has a range due to errors (such as sensor errors, errors due to the influence of pressure and temperature) and the influence of the oil quantity, and its minimum value is "0.85 A". Similarly, the value of the specific frequency component during abnormal oil quantity also has a range due to the influence of errors, and its maximum value is "1.23 A". Therefore, the above threshold value cannot be set appropriately. Note that the reason why the value of the specific frequency component changes due to errors and the influence of the oil quantity is that the waveform of the physical quantity (a physical quantity correlated with the state of the compressor (50)) changes due to errors and the influence of the oil quantity.

[0082] As shown in FIG. 5, the temporal change of the specific frequency component (the temporal change during the period (TA) in the example of FIG. 5) at the time of occurrence of a breakdown in the sealing property of the compression chamber (68) due to lubricating oil is much larger than the temporal change of the specific frequency component accompanying the increase and decrease of the oil quantity during normal oil quantity (the temporal change during the period (TB) in the example of FIG. 5). The vertical axis in FIG. 5 shows the percentage (ratio to the reference) of the amplitude value of the specific frequency component with respect to the amplitude value of the specific frequency component at the start of the period (TB) as the reference (100%). For example, the temporal change of the specific frequency component at the time of occurrence of a breakdown in the sealing property of the compression chamber (68) due to lubricating oil is "a change of decreasing by 40% in 30 seconds (1.333% / second)", and the temporal change of the specific frequency component accompanying the increase and decrease of the oil quantity during normal oil quantity is "a change of decreasing by 11% in 1800 seconds (0.006% / second)".

[0083] Therefore, based on the magnitude of the temporal change of a specific frequency component, it is possible to identify a sudden change (specifically, a sudden drop) in the specific frequency component when the sealing performance of the compression chamber (68) by the lubricating oil breaks down. For example, by comparing a value indicating the magnitude of the temporal change of the specific frequency component with a threshold value, it is possible to estimate whether the state of the compressor (50) is in a state where "the sealing performance of the compression chamber (68) by the lubricating oil has broken down".

[0084] Also, in order to set a threshold value to be compared with the magnitude of the temporal change of the specific frequency component, it is not necessary to consider errors (such as sensor errors, errors due to the influence of pressure and temperature, etc.) included in the specific frequency component. Therefore, it is possible to appropriately set the threshold value more easily than in the case of setting a threshold value to be compared with the magnitude of the specific frequency component.

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

[0086] In addition, in order to reduce errors included in the specific frequency component, it is conceivable to individually prepare threshold values for each solid of the sensor or for each pressure and temperature. However, in this method, the state estimation algorithm becomes complicated and the calculation load increases, so the cost of a computing device such as a processor becomes high. On the other hand, in the method in the embodiment (state estimation based on the magnitude of the temporal change of the specific frequency component), it is sufficient to set a single threshold value for the magnitude of the temporal change of the specific frequency component, so an increase in the calculation load can be suppressed and an existing processor can be used as it is.

[0087] In addition, in order to grasp the influence of the fuel quantity on specific frequency components, it is conceivable to separately provide a sensor for detecting the fuel quantity. However, with this method, the cost increases due to the installation of the sensor. On the other hand, in the method according to the embodiment (state estimation based on the magnitude of the temporal change of specific frequency components), it is not necessary to separately provide a sensor for detecting the fuel quantity, so an increase in cost due to the installation of the sensor can be avoided.

[0088] In addition, the method according to the embodiment (state estimation based on the magnitude of the temporal change of specific frequency components) can capture the change in the current waveform at the time of abnormality by focusing on the frequency components. By monitoring while focusing on the frequency components in this way, abnormalities can be detected with higher accuracy than when monitoring the effective value or the average value.

[0089] 〔Liquid compression〕 Next, with reference to FIG. 6, liquid compression will be described. 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 the torque pulsation of the compressor (50) suddenly increases. Specifically, the magnitude of the primary component of the rotational frequency of the motor (60) in the torque suddenly increases. Therefore, when liquid compression occurs, the primary component of the rotational frequency of the motor (60) in the current vector amplitude (Ia) suddenly increases.

[0090] As shown in FIG. 6, when liquid compression occurs at time (t1), the amplitude value of the specific frequency component suddenly rises. After that, when the liquid working fluid disappears from the compression mechanism (65), the amplitude value of the specific frequency component returns to its original value.

[0091] Also, as shown in FIG. 6, the amplitude value of the specific frequency component during hydraulic compression is larger than the amplitude value of the specific frequency component during normal operation. Therefore, in order to discriminate between normal operation and hydraulic 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 consider the error included in the specific frequency component (such as the error of the sensor, the error due to the influence of pressure and temperature, etc.), so it may be difficult to appropriately set the above threshold value.

[0092] For example, when the median value of the specific frequency component during normal operation (for example, the median value of the assumed change range) is "1.37 A" and the median value of the specific frequency component during hydraulic compression is "1.96 A", it is desirable that the threshold value for discriminating between normal operation and hydraulic compression be set between "1.37 A" and "1.96 A". However, the value of the specific frequency component during normal operation has a width due to errors (such as sensor errors, errors due to the influence of pressure and temperature, etc.) and the influence of the fuel quantity, and its maximum value is "1.89 A". Similarly, the value of the specific frequency component during hydraulic compression also has a width due to errors and the influence of the fuel quantity, and its minimum value is "1.44 A". Therefore, the above threshold value cannot be appropriately set.

[0093] Note that, as shown in FIG. 7, the temporal change of the specific frequency component at the time of occurrence of hydraulic compression (the temporal change during the period (TC) in the example of FIG. 7) is significantly larger than the temporal change of the specific frequency component during normal operation (the temporal change during the period (TD) in the example of FIG. 7). The vertical axis in FIG. 7 shows the percentage (ratio to the reference) of the amplitude value of the specific frequency component with respect to the amplitude value of the specific frequency component at the start of the period (TD) as the reference (100%). For example, the temporal change of the specific frequency component at the time of occurrence of hydraulic compression is "a change that increases by 43% in 20 seconds (2.15% / second)", and the temporal change of the specific frequency component during normal operation is "a change that increases or decreases by 11% in 1800 seconds (0.006% / second)".

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

[0095] Also, in order to set a threshold value to be compared with the magnitude of the temporal change of the specific frequency component, it is not necessary to consider errors (such as sensor errors, errors due to the influence of pressure and temperature, etc.) included in the specific frequency component. Therefore, it is possible to appropriately set the threshold value more than when setting the threshold value to be compared with the magnitude of the specific frequency component.

[0096] Specifically, the temporal change of the specific frequency component associated with changes in pressure and temperature is sufficiently smaller than the temporal change of the specific frequency component at the time of occurrence of liquid compression. Also, the temporal change of the specific frequency component associated with changes in pressure and temperature is sufficiently smaller than the difference between "the temporal change of the specific frequency component at the time of occurrence of liquid compression" and "the temporal change of the specific frequency component during normal operation".

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

[0098] Note that 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 the estimation process based on a signal indicating the physical quantity. Specific examples of the signal indicating the physical quantity will be described in detail later.

[0099] Also, 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). Here, M and N are integers, and N < M.

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

[0101] In other words, in this example, the "state in which the specific frequency component changes abruptly" of the compressor (50) estimated by the control unit (31) is a state where "the sealing performance of the compression chamber by the lubricating oil has failed" or a state where "the liquid working fluid is sucked into the compression mechanism (65) and is in a liquid compression state where it is compressed in the compression mechanism (65)".

[0102] Note that in this example, the state where "the sealing performance of the compression chamber by the lubricating oil has failed" is specifically a state where "the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil sump portion (54), resulting in the failure of the sealing performance of the compression chamber by the lubricating oil". The control unit (31) may estimate whether the state of the compressor (50) is a state where "the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil sump portion (54)".

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

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

[0105] Note that the sensor for acquiring "information for obtaining a physical quantity correlated with the state of the compressor (50)" in the estimation process may be used also as a sensor (e.g., a current sensor, etc.) used in the control process, or may be a sensor provided separately from the sensors 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 the temporal change of a specific frequency component (e.g., the primary component) included in the physical quantity obtained in step (S1). In this example, the control unit (31) derives, every predetermined estimation time, a value (hereinafter referred to as "index value") indicating the magnitude of the temporal change of the specific frequency component included in the physical quantity, based on the physical quantity obtained in step (S1). Then, the control unit (31) compares the index value with a threshold value, and estimates whether or not the state of the compressor (50) is a state where "the specific frequency component changes abruptly", according to the result of the comparison. By repeatedly performing such processing, the index value is derived for 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) based on the magnitude of the temporal change of a specific frequency component included in a physical quantity correlated with the state of the compressor (50) in the estimation process.

[0108] According to the above configuration, by estimating the state of the compressor (50) based on the magnitude of the temporal change 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 abruptly".

[0109] Further, 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 failed".

[0110] According to the above configuration, based on the magnitude of the temporal change of the specific frequency component, 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 failed".

[0111] Further, 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 sump portion (54) where lubricating oil accumulates and an oil supply path (100) for supplying the lubricating oil accumulated in the oil sump portion (54) to the compression chamber (68). The oil supply path (100) has a suction port (101a), and by immersing the suction port (101a) in the lubricating oil accumulated in the oil sump portion (54), it becomes possible to supply the lubricating oil sucked from the suction port (101a) to the compression chamber (68). 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 suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil sump portion (54)".

[0112] According to the above configuration, based on the magnitude of the temporal change of the specific frequency component, it is possible to estimate 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 sump portion (54)".

[0113] Also, in the drive system (10) of the embodiment, in the estimation process, the control unit (31) estimates whether or not 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, based on the magnitude of the temporal change of the specific frequency component, it is possible to estimate that 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)".

[0115] (Specific 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. This signal is roughly classified into a DC signal and an AC signal.

[0116] [Specific example of a DC signal] Examples of DC signals include a "signal correlated with the phase current (iu, iv, iw) of the motor (60)", a "signal correlated with the phase voltage (Vu, Vv, Vw) of the motor (60)", and a "signal correlated with the power of the motor (60)".

[0117] Another example of a DC signal includes a "current (iγ, iδ) obtained by coordinate-transforming the phase current (iu, iv, iw) of the motor (60) with the phase (ωi·t) of the phase current (iu, iv, iw) of the motor (60)", a "voltage (Vγ, Vδ) obtained by coordinate-transforming the phase voltage (Vu, Vv, Vw) of the motor (60) with the phase (ωv·t) of the phase voltage (Vu, Vv, Vw) of the motor (60)", a "current (iζ, iη) obtained by coordinate-transforming the phase current (iu, iv, iw) of the motor (60) with the phase (ωv·t) of the phase voltage (Vu, Vv, Vw) of the motor (60)", and a "voltage (Vζ, Vη) obtained by coordinate-transforming the phase voltage (Vu, Vv, Vw) of the motor (60) with the phase (ωi·t) of the phase current (iu, iv, iw) of the motor (60)".

[0118] As yet another example of a direct current signal, there are "the dq-axis fluxes (λd, λq) obtained by coordinate transformation in accordance with the armature interlinkage flux by a permanent magnet" and "the magnitude λ0 of the armature interlinkage flux vector obtained by synthesizing the armature interlinkage flux by a permanent magnet and the armature reaction".

[0119] In the following description, the "phase currents (iu, iv, iw) of the motor (60)" are the phase currents (iu, iv, iw) of the motor (60) detected by the phase current detection unit (41). The "phase voltages (Vu, Vv, Vw) of the motor (60)" are the phase voltages (Vu, Vv, Vw) of the motor (60) indicated by the voltage command value used inside 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 "electrical angular frequency (ω) of the motor (60)" is 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 the phase current of the motor] Specific examples of signals correlated with the phase currents (iu, iv, iw) of the motor (60) include the current vector amplitude (Ia), the squared value of the current vector amplitude (Ia 2 ), the phase current amplitude (I), the phase current effective value (Irms), and the like.

[0121] Note that the current vector amplitude (Ia) and the squared value of the current vector amplitude (Ia 2 ) are an example of a value corresponding to the sum of the squared values of each of the three-phase phase currents (iu, iv, iw) of the motor (60). A value corresponding to the sum of the squared values of each of the three-phase 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). Also, the current vector amplitude (Ia) may be derived based on the α-phase current (iα) and the β-phase current (iβ) obtained by converting the phase currents (iu, iv, iw) of the motor (60) to a stationary coordinate system. Further, the current vector amplitude (Ia) may be derived based on the M-axis current (iM) and the 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 fundamental magnetic flux. Additionally, the current vector amplitude (Ia) may be derived based on the d-axis current (id) and the q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (60) by 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 value of the current vector amplitude The square value of the current vector amplitude (Ia 2 ) is derived based on the phase currents (iu, iv, iw) of the motor (60). Also, the square value of the current vector amplitude (Ia 2 ) may be derived based on the α-phase current (iα) and the β-phase current (iβ) obtained by converting the phase currents (iu, iv, iw) of the motor (60) to a stationary coordinate system. Further, the square value of the current vector amplitude (Ia 2 ) may be derived based on the M-axis current (iM) and the 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 fundamental magnetic flux. Additionally, the square value of the current vector amplitude (Ia 2 ) may be derived based on the d-axis current (id) and the q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (60) by an angle based on the direction of the magnetic pole position. Specifically, the square value of the current vector amplitude (Ia 2 ) can be expressed as follows.

[0125] [Number]

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

[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) Others In the above description, the case where the current vector amplitude (Ia) is derived based on the three-phase phase currents (iu, iv, iw) of the motor (60) is taken as an example. However, the current vector amplitude (Ia) may be derived based on two of the three-phase phase currents (iu, iv, iw) of the motor (60). Also, the current vector amplitude (Ia) may be derived based on the DC current of the inverter (23) detected by a DC current detection unit (for example, a shunt resistor, not shown) provided in the motor drive device (20). The same applies to the square value (Ia 2 ) of the current vector amplitude.

[0131] [2. Specific examples of signals correlated with the phase voltage of the motor] As specific examples of signals correlated with the phase voltages (Vu, Vv, Vw) of the motor (60), there are the voltage vector amplitude (Va), the squared value of the voltage vector amplitude (Va 2 ), the phase voltage amplitude (V), the root mean square value of the phase voltage (Vrms), and the like.

[0132] Note that the voltage vector amplitude (Va) and the squared value of the voltage vector amplitude (Va 2 ) are examples of values corresponding to the sum of the squared values of each of the three-phase voltages (Vu, Vv, Vw) of the motor (60). The value corresponding to the sum of the squared values of each 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). Also, the voltage vector amplitude (Va) may be derived based on the α-phase voltage (Vα) and the β-phase voltage (Vβ) obtained by converting the phase voltages (Vu, Vv, Vw) of the motor (60) to a stationary coordinate system. Also, the voltage vector amplitude (Va) may be derived based on the M-axis voltage (VM) and the 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. Also, the voltage vector amplitude (Va) may be derived based on the d-axis voltage (Vd) and the 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 the voltage vector amplitude The squared value of the voltage vector amplitude (Va 2 ) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (60). Also, the squared value of the voltage vector amplitude (Va2 ) may be derived based on the α-phase voltage (Vα) and β-phase voltage (Vβ) obtained by converting the phase voltages (Vu, Vv, Vw) of the motor (60) into a fixed coordinate system. Also, the squared value (Va of the voltage vector amplitude 2 ) may be derived based on the M-axis voltage (VM) and 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. Also, the squared value (Va of the voltage vector amplitude 2 ) may be derived based on the d-axis voltage (Vd) and 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 squared value (Va of the voltage vector amplitude 2 ) can be expressed as follows.

[0136]

Equation

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

[0138]

Equation

[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]

Equation

[0141] (5) Others In the above description, the case where the voltage vector amplitude (Va) is derived based on the three-phase phase voltages (Vu, Vv, Vw) of the motor (60) has been taken as an example. However, the voltage vector amplitude (Va) may be derived based on the phase voltages of two phases among the three-phase phase voltages (Vu, Vv, Vw) of the motor (60). The same applies to the squared value (Va 2 ) of the voltage vector amplitude.

[0142] [3. Specific Examples of Signals Correlated with the Power of the Motor] Examples of signals correlated with the power of the motor (60) include instantaneous power (p), instantaneous reactive power (q), apparent power (S), active power (P), reactive power (Q), etc.

[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). Also, the instantaneous power (p) may be derived based on the α-phase current (iα) and β-phase current (iβ) obtained by converting the phase currents (iu, iv, iw) of the motor (60) to the stationary coordinate system, and the α-phase voltage (Vα) and β-phase voltage (Vβ) obtained by converting the phase voltages (Vu, Vv, Vw) of the motor (60) to the stationary coordinate system. Also, the instantaneous power (p) may be derived based on the M-axis current (iM) and 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 the M-axis voltage (VM) and 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. Also, the instantaneous power (p) may be derived based on the d-axis current (id) and q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (60) by an angle based on the direction of the magnetic pole position, and the d-axis voltage (Vd) and 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 instantaneous power (p) can be expressed as follows.

[0144] [Number]

[0145] (2) Instantaneous Reactive Power The instantaneous reactive power (q) is derived based on the α-phase current (iα) and β-phase current (iβ) obtained by converting the phase currents (iu, iv, iw) of the motor (60) into a stationary coordinate system, and the α-phase voltage (Vα) and β-phase voltage (Vβ) obtained by converting the phase voltages (Vu, Vv, Vw) of the motor (60) into a stationary coordinate system. Also, the instantaneous reactive power (q) may be derived based on the M-axis current (iM) and 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 the M-axis voltage (VM) and 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. Further, the instantaneous reactive power (q) may be derived based on the d-axis current (id) and q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (60) by an angle based on the direction of the magnetic pole position, and the d-axis voltage (Vd) and 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 instantaneous reactive power (q) can be expressed as follows.

[0146] [Number]

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

[0148] [Number]

[0149] (4) Active Power The active power (P) is derived based on the effective value of the phase voltage (Vrms), the effective value of the phase current (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 (for example, the U-phase voltage (Vu)) and one phase current (for example, the U-phase current (iu)), and is derived based on the phase of the phase current (ωi) and the phase of the phase voltage (ωv). Specifically, the active power (P) can be expressed as follows.

[0150]

Equation

[0151] (5) Reactive power The reactive power (Q) is derived based on the effective value of the phase voltage (Vrms), the effective value of the phase current (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 derived based on the phase of the phase current (ωi) and the phase of the phase voltage (ωv). Specifically, the reactive power (Q) can be expressed as follows.

[0152]

Equation

[0153] [4. Current obtained by coordinate transformation of the 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) with the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (60) can be expressed as follows.

[0154]

Equation

[0155] [5. Voltage obtained by coordinate transformation of the phase voltage with the phase of the phase voltage] The voltages (Vγ, Vδ) obtained by performing a coordinate transformation on 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) can be expressed as follows.

[0156] [Equation]

[0157] [6. Current obtained by performing a coordinate transformation on the phase current with the phase of the phase voltage] The currents (iζ, iη) obtained by performing a coordinate transformation on 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) can be expressed as follows.

[0158] [Equation]

[0159] [7. Voltage obtained by performing a coordinate transformation on the phase voltage with the phase of the phase current] The voltages (Vζ, Vη) obtained by performing a coordinate transformation on 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) can be expressed as follows.

[0160] [Equation]

[0161] [6. Magnitudes of the dq-axis flux and the armature interlinkage flux vector] The magnitudes λ0 of the dq-axis fluxes (λd, λq) transformed in accordance with the armature interlinkage flux due to the permanent magnet and the armature interlinkage flux vector obtained by synthesizing the armature interlinkage flux of the permanent magnet and the armature reaction can be expressed as follows. In the following equations, "Ld" is the d-axis inductance and "Lq" is the q-axis inductance.

[0162] [Equation]

[0163] 〔7. Other Examples of DC Signals〕 Also, 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-to-line voltage of the motor (60) and further performing a rotational coordinate conversion. For example, the DC signal may be the d-axis current and q-axis current obtained by performing a rotational coordinate conversion on the α-axis current and 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 direction of the magnetic poles of the rotor of the motor (60). Also, the DC signal may be the M-axis current and T-axis current obtained by performing a rotational coordinate conversion on the α-axis current and β-axis current at an angle based on the direction of the primary magnetic flux of the rotor of the motor (60).

[0164] Also, the DC signal may 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 section (22), the current flowing between the converter (21) and the DC section (22), the current flowing between the DC section (22) and the inverter (23), etc.

[0165] 〔Specific Examples of AC Signals〕 Examples of the AC signal include "the phase current (iu, iv, iw) of the motor (60)", "the phase voltage (Vu, Vv, Vw) of the motor (60)", and "the mutual magnetic flux linkage (Ψfu, Ψfv, Ψfw) of each phase".

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

[0167]

Equation

[0168] Another example of the AC signal includes the current, voltage, and mutual magnetic flux linkage in the fixed coordinates obtained by performing a three-phase to two-phase conversion on the above AC signal.

[0169] The alternating current signal may be, for example, the line current or line voltage of the motor (60). The alternating current signal may also be a two-phase alternating current (for example, α-axis current and β-axis current) or two-phase alternating voltage obtained by converting a three-phase current or voltage or line current or line voltage into two phases. The alternating current may also be a current flowing between the commercial power supply system (specifically, the alternating current power supply (5)) and the converter (21) of the motor drive device (20).

[0170] (Specific example of estimation process) Next, a specific example of the estimation process will be described. Examples of the estimation process include the following four estimation processes (first to fourth estimation processes). Hereinafter, a case where the estimation process is performed based on the amplitude of a specific frequency component will be described as an example. The "specific frequency component" in the following description refers to the "amplitude value of the specific frequency component".

[0171] In the following, a 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) will be referred to as an "index value". For example, in the estimation process, the control unit (31) derives the index value at each predetermined processing cycle, and estimates whether the state of the compressor (50) is a state where "the specific frequency component changes rapidly" according to the result of comparison between the index value and a threshold value.

[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 specified by the second filter". The time constant of the second filter is larger than the time constant of the first filter.

[0173] In addition, if the time constant of the first filter is too large, there is a possibility that the temporal change (temporal change between 20 seconds and 30 seconds) of the specific frequency component that appears during an abnormality (for example, when the sealing performance of the compression chamber (68) by the lubricating oil fails) may not be detected. Therefore, for example, the time constant of the first filter may be set to "less than 21.556 seconds", and specifically, it may be set to "3.59 seconds".

[0174] Also, if the time constant of the second filter is too small, it will be close to the time constant of the first filter, and the change in the index value (the above ratio value) during an abnormality will be small. Conversely, if the time constant of the second filter is too large, there is a possibility that the influence of the temporal changes in the rotational speed, pressure, and temperature of the motor (60) of the compressor (50) will increase. 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", and specifically, it may be set to "64.67 seconds".

[0175] In the first estimation process, the control unit (31) determines whether or not the index value (in this example, the ratio value obtained by dividing the "first filter value (F1)" by the "second filter value (F2)") in the first estimation process is lower than a predetermined threshold value (in this example, the threshold value for detecting a sharp drop in the specific frequency component). When the index value is lower than the threshold value, the control unit (31) estimates that the state of the compressor (50) is a state where "the specific frequency component changes rapidly (in this example, drops sharply)". On the other hand, when the index value is not lower than the threshold value, the control unit (31) estimates that the state of the compressor (50) is not a state where "the specific frequency component changes rapidly (in this example, drops sharply)".

[0176] In the first estimation process, the control unit (31) may also estimate whether or not the state of the compressor (50) is a state where "the specific frequency component rises rapidly". In this case, for example, when the index value exceeds a predetermined threshold value (the threshold value for detecting a rapid rise in the specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "the specific frequency component rises rapidly".

[0177] Alternatively, 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 sharp drop in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "a specific frequency component changes rapidly (specifically, drops sharply)".

[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 sharp drop in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "a specific frequency component changes rapidly (specifically, drops sharply)".

[0180] 〔Second Estimation Process〕 Next, with reference to FIG. 10, the second estimation process will be described. The index value in the second estimation process is a difference value obtained by subtracting the "second time average value (A2)", which is the average value of specific frequency components within a predetermined period (Ta) ending at the "second time (t k )", from the "first time average value (A1)", which is the average value of specific frequency components within a predetermined period (Ta) ending at the "first time (t k ) and is T time earlier than the first time (t k-1 )".

[0181] Note that if the predetermined time (Ta) is too long, there is a possibility that the temporal change (temporal change between 20 seconds and 30 seconds) of the specific frequency component that appears during an abnormality (for example, when the sealing performance of the compression chamber (68) by lubricating oil fails) may not be detected. Therefore, for example, the predetermined period (Ta) may be set to "less than 60 seconds", and specifically, it may be set to "5 seconds".

[0182] Also, if the time (T) is too short, the change in the index value (the above-mentioned difference value) during an abnormality becomes small. Conversely, if the time (T) is too long, there is a risk that the influence of the temporal changes in the rotational speed, pressure, and temperature of the motor (60) of the compressor (50) will increase. Therefore, for example, the time (T) may be set to "60 seconds or more and 600 seconds or less", and specifically, it may be set to "60 seconds".

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

[0184] In the second estimation process, the control unit (31) may also estimate whether or not the state of the compressor (50) is a state where "the specific frequency component suddenly decreases". In this case, for example, when the index value is lower than a predetermined threshold value (a threshold value for detecting a sudden decrease in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "the specific frequency component suddenly decreases".

[0185] Also, 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 less than a predetermined threshold value (a threshold value for detecting a sudden increase in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "the specific frequency component changes suddenly (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 less than a predetermined threshold value (a threshold value for detecting a sudden increase in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "the specific frequency component changes suddenly (specifically, suddenly increases)".

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

[0189] Note that if the first period (T1) is too long, there is a possibility that the temporal change (temporal change between 20 seconds and 30 seconds) of the specific frequency component that appears during an abnormality (for example, when the sealing performance of the compression chamber (68) by lubricating oil fails) may not be detected. Therefore, for example, the first period (T1) may be set to "less than 60 seconds", and specifically, may be set to "10 seconds".

[0190] Also, if the second period (T2) is too short, the change in the index value (the above ratio value) during an abnormality becomes small. Conversely, if the second period (T2) is too long, there is a risk that the influence of the temporal changes in the rotational speed, pressure, and temperature of the motor (60) of the compressor (50) will increase. Therefore, for example, the second period (T2) may be set to "60 seconds or more and 600 seconds or less", and specifically may be set to "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, the 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, the threshold value for detecting a sudden increase in a specific frequency component). When the index value exceeds the threshold value, the control unit (31) estimates that the state of the compressor (50) is a state where "the specific frequency component suddenly changes (in this example, suddenly increases)". On the other hand, when 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 where "the specific frequency component suddenly changes (in this example, suddenly increases)".

[0192] In the third estimation process, the control unit (31) may also estimate whether or not the state of the compressor (50) is a state where "the specific frequency component suddenly drops". In this case, for example, when the index value is below a predetermined threshold value (the 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 where "the specific frequency component suddenly drops".

[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 less than a predetermined threshold value (a threshold value for detecting a sudden increase in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "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 less than a predetermined threshold value (a threshold value for detecting a sudden increase in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "the specific frequency component suddenly changes (specifically, suddenly increases)".

[0196] 〔Fourth Estimation Process〕 Next, with reference to FIG. 13, the fourth estimation process will be described. The index value in the fourth estimation process is a ratio value obtained by dividing the "instantaneous value (X) of the specific frequency component at a predetermined time (t i )(for example, the current time)" by the "average value (AA) of the specific frequency component within a predetermined period (Tb) having the predetermined time (t i ) as the end point.

[0197] Note that if the predetermined period (Tb) is too short, the change in the index value (the above-mentioned difference value) during an abnormality becomes small. Conversely, if the predetermined period (Tb) is too long, there is a possibility that the influence of the temporal changes in the rotational speed, pressure, and temperature of the motor (60) of the compressor (50) becomes large. Therefore, for example, the predetermined period (Tb) may be set to "60 seconds or more and 600 seconds or less", and specifically, it may be set to "180 seconds".

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

[0199] Note that in the fourth estimation process, the control unit (31) may estimate whether or not the state of the compressor (50) is a state in which "a specific frequency component rises rapidly". In this case, for example, when the index value exceeds a predetermined threshold value (a threshold value for detecting a rapid rise in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state in which "a specific frequency component rises rapidly".

[0200] Also, 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 rapid drop in a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state in which "a specific frequency component changes rapidly (specifically, drops rapidly)".

[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 a specific frequency component), the control unit (31) may estimate that the state of the compressor (50) is a state where "a specific frequency component changes suddenly (specifically, drops suddenly)".

[0203] (Refrigeration system) FIG. 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) has a compressor (50), a radiator (RR5), a decompression mechanism (RR6), and an evaporator (RR7). In this example, the decompression 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) rotationally drives the compression mechanism (65) by rotationally driving the drive shaft. 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 decompression mechanism (RR6) and evaporates in the evaporator (RR7). Then, the refrigerant flowing out of the evaporator (RR7) flows into the compressor (50).

[0207] In this example, the refrigeration system (RR) is an air conditioner. The air conditioner may be a cooling-only unit or a heating-only unit. Also, the air conditioner may 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) for switching the circulation direction of the refrigerant. Further, the refrigeration system (RR) may be a water heater, a chiller unit, a cooling device for cooling the air inside a storage, etc. The cooling device cools the air inside a refrigerator, a freezer, a container, etc.

[0208] (Findings obtained from experiments) Next, with reference to FIGS. 15 and 16, the experiments conducted by the inventor of the present application and the findings obtained from those experiments will be described.

[0209] As shown in FIG. 15, in the experiment, the "amplitude value of a specific frequency component" included in the physical quantity (in this example, the current vector amplitude (Ia)) obtained within a period of 10 seconds was derived every 1 second. Then, 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 defined as the "index value". Expressed by a formula, the index value is "|1 - (MA1 / MB2)|". It can be said that the above index value is a modified example of the index value in the third estimation process.

[0210] Note that the first moving average value (MA1) is the average value of 10 amplitude values derived within the first period (T1) of 10 seconds with the time (ti) at which the latest amplitude value was derived as the end. The second moving average value (MA2) is the average value of 180 amplitude values derived within the second period (T2) of 3 minutes with the time (ti) at which the latest amplitude value was derived as the end. For example, the first period (T1) and the second period (T2) can be illustrated as shown in FIG. 12.

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

[0212] (1) The suction port (101a) of the oil supply path (100) is immersed in the lubricating oil accumulated in the oil reservoir section (54). (2) 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. Note that the above steady state may be determined based on the use of the compressor (50) or the like.

[0213] As shown in FIG. 16, the index value observed when the compressor (50) is in a steady state was a value less than "0.1". When the compressor (50) changes from the steady state to a predetermined state (a state in which a specific frequency component changes abruptly), the index value rises beyond "0.1" to a maximum value (for example, about 3.5). Also, even when the compressor (50) is in a steady state, the index value fluctuates slightly. When observing the index values included in the 10-minute measurement period, the peak (maximum value) of the slight fluctuation of the index value could be observed.

[0214] In addition, in order to verify the influence due to individual differences in the compressor (50), the operation of replacing the compressor (50) provided in the refrigeration system (RR) with another compressor (50) (a compressor (50) of the same model) and observing the above index values was repeated. As a result, the index value when the compressor (50) is in a steady state was a value less than "0.1" regardless of the individual differences in the compressor (50).

[0215] From the above experiments, the inventors of the present application obtained the following findings. Hereinafter, the amplitude value of a specific frequency component included in the physical quantity obtained within a period of 10 seconds is derived every second, and the average value of 10 amplitude values derived within the first period (T1) of 10 seconds with the time (ti) when the latest amplitude value was derived as the end is defined as the "first moving average value (MA1)", and the average value of 180 amplitude values derived within the second period (T2) of 3 minutes with the time (ti) when the latest amplitude value was derived as the end is defined as the "second moving average value (MA2)", and the condition that 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 is defined as the "index value" is described as the "verification condition".

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

[0217] Note that 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 a coping process at the same timing as the coping process when the threshold value for the above index value (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) is set to "0.1". Hereinafter, the index value, which is 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", is described as the "reference index value".

[0218] [Threshold for the index value in the first estimation process] When the index value is "the ratio value obtained by dividing the first filter value (F1) by the second filter value (F2)", the threshold is set in the range "from 0.89 to 1.11". If this 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 the ratio value obtained by dividing the first filter value (F1) by the second filter value (F2) and 1", the threshold is set to "0.11". If this index value exceeds the above threshold, the reference index value will exceed "0.1".

[0220] [Threshold for the index value in the second estimation process] When 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 in 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 for the index value in the third estimation process] When the index value is "the ratio value obtained by dividing the first moving average value (MA1) by the second moving average value (MA2)", the threshold is set in the range "from 0.9 to 1.1". If this index value deviates from the above range, the reference index value will exceed "0.1".

[0222] [Threshold for the index value in the fourth estimation process] When the index value is "the 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 in the range "from 0.69 to 1.31". If this 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 the 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 value is set to "0.31". When this index value exceeds the above threshold value, the reference index value will exceed "0.1".

[0224] (Other Embodiments) In the above description, as an example of a physical quantity correlated with the state of the motor (60), a signal indicating a physical quantity correlated with the voltage or current of the motor (60) is given, but it is not limited thereto. For example, the physical quantity may be a signal indicating the vibration of the motor (60), or a signal indicating the sound of the motor (60). The signal indicating the vibration of the motor (60) may be acquired by a vibration sensor (not shown) provided in the compressor (50) or the device (1). The signal indicating the sound of the motor (60) may be acquired by a microphone (not shown) provided in the compressor (50) or the device (1). The sound may be a sound within the audible range or a sound outside the audible range (ultrasonic wave). Thus, the physical quantity may be any one 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 the sound around the compressor (50).

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

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

[0227] In the above description, the case where the compressor (50) is a "scroll compressor" has been taken as an example, but it is not limited thereto. For example, the compressor (50) may be a swing compressor in which a piston and a blade are integrally formed, a rotary compressor in which a piston and a blade are separately formed, or other types of rotary compressors.

[0228] Further, the compressor (50) may be a two-cylinder type compressor (swing compressor or rotary compressor) having two compression chambers.

[0229] As shown in FIG. 17, the pulsation cycle of the torque of the two-cylinder type compressor (the pulsation cycle during normal operation) is a cycle corresponding to 1 / 2 of the rotation cycle of the motor (60). Further, in a two-cylinder type compressor, when liquid compression occurs, a sudden change in the torque of the compressor appears at a cycle corresponding to 1 / 2 of the rotation cycle of the motor (60). Therefore, in a two-cylinder type compressor, when liquid compression occurs, the secondary component of the torque of the compressor (50) suddenly changes (specifically, suddenly increases), and as a result, the secondary component of the current vector amplitude (Ia) suddenly changes (specifically, suddenly increases). Note that the "secondary component" is a frequency component having a frequency twice the mechanical angular frequency of the motor (60).

[0230] When the compressor (50) is a "two-cylinder type compressor", the "specific frequency component processed in the estimation process" may be the "secondary component". Thereby, it is possible to estimate whether the state of the compressor (50) is a "liquid compression state" or not.

[0231] In the above description, the various sensors may be contact type sensors or non-contact type sensors. The contact type sensor may be attached to the casing (51) of the compressor (50), or may be attached to a pipe or an electric wire arranged near the compressor (50). The non-contact type sensor may be attached to a location close to the casing (51) of the compressor (50), a location close to a pipe or an electric wire arranged near the compressor (50), a location close to the device (1) on which the compressor (50) is mounted, or the like.

[0232] Also, in the above description, the detection unit that detects 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] Also, in the above description, the change process may be "a change process for changing the operating conditions of the system including the compressor (50)". In the change process, not only the operating conditions of the motor (60) but also the operating conditions of "other components excluding the motor (60)" included in the system including the compressor (50) may be changed. Examples of the change process include a process of stopping the motor (60), a process of accelerating the motor (60), a process of decelerating the motor (60), a process of decreasing the current flowing through the motor (60), a process of increasing the current flowing through the motor (60), a process of increasing the opening degree of the expansion valve (electric valve) constituting the decompression mechanism (RR6), a process of decreasing the opening degree of the expansion valve (electric valve) constituting the decompression mechanism (RR6), a process of increasing the pressure of the working fluid discharged from the compressor (50), a process of decreasing the pressure of the working fluid discharged from the compressor (50), a process of increasing the temperature of the working fluid discharged from the compressor (50), a process of decreasing the temperature of the working fluid discharged from the compressor (50), a process of returning the lubricating oil flowing through the fluid flow path together with the working fluid to the compressor (50), a process of increasing the rotational speed of the fan (not shown) that conveys air to the radiator (RR5) or the evaporator (RR7), a process of decreasing the rotational speed of the fan that conveys air to the radiator (RR5) or the evaporator (RR7), and the like.

[0234] Also, although the embodiments and modified examples have been described, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Also, the elements according to the above embodiments, modified examples, and other embodiments may be combined or replaced as appropriate.

[0235] (Summary of Embodiment) Summarizing 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). This control device includes a control unit (31). When the relationship between an 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 a predetermined threshold value becomes a predetermined relationship, the control unit (31) performs a countermeasure process including at least one of an output process of outputting information indicating that the state of the compressor (50) is a predetermined state and a change process of changing the operating conditions of the system.

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

[0237] In the above configuration, by performing a countermeasure process when the relationship between an 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 a predetermined threshold value becomes a predetermined relationship, it is possible to appropriately perform a process for coping with the case where the state of the compressor (50) is a predetermined state (a state where the specific frequency component changes abruptly).

[0238] Note that the control unit (31) sets the index value to "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" under the 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 first moving average value (MA1) is set to "the average value of 10 amplitude values derived within the first period (T1) of 10 seconds with the time (ti) at which the latest amplitude value was derived as the end point", and the second moving average value (MA2) is set to "the average value of 180 amplitude values derived within the second period (T2) of 3 minutes with the time (ti) at which the latest amplitude value was derived as the end point". When the threshold value is set to "a value that is 1.1 times or more the maximum value of the index value obtained during a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state", it may be configured to perform a coping process when the index value exceeds the threshold value.

[0239] As a result of intensive research, the inventor of the present application has found that by setting the threshold value for the above index value to "a value that is 1.1 times or more the maximum value of the index value obtained during 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 the specific frequency component changes rapidly) when the above index value exceeds the above threshold value.

[0240] In the above configuration, by performing a coping process when the above index value exceeds the above threshold value, it is possible to appropriately perform a process for coping with the case where the state of the compressor (50) is in a predetermined state (a state in which the specific frequency component changes rapidly).

[0241] Further, under the condition that the amplitude value of a specific frequency component included in the physical quantity obtained within a period of 10 seconds is derived every second, the control unit (31) sets the index value to "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", sets the first moving average value (MA1) to "the average value of 10 amplitude values derived within the first period (T1) of 10 seconds with the time (ti) at which the latest amplitude value was derived as the end point", sets the second moving average value (MA2) to "the average value of 180 amplitude values derived within the second period (T2) of 3 minutes with the time (ti) at which the latest amplitude value was derived as the end point", and when the threshold value is "0.1", it may be configured to perform a coping process when the index value exceeds the threshold value.

[0242] As a result of intensive research, the inventor of the present application has found that by setting the threshold value for the above index value to "0.1", when the above index value exceeds the above threshold value, it can be estimated that the state of the compressor (50) is a predetermined state (a state in which a specific frequency component changes rapidly).

[0243] In the above configuration, by performing a coping process when the above index value exceeds the above threshold value, it is possible to appropriately perform a process for coping with the case where the state of the compressor (50) is a predetermined state (a state in which a specific frequency component changes rapidly).

[0244] Further, 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 performance of the compression chamber (68) by the lubricating oil has failed.

[0245] As a result of intensive research, the inventor of the present application has found the phenomenon that "when the sealing performance of the compression chamber (68) by the lubricating oil fails in the compressor (50), a specific frequency component included in the physical quantity correlated with the state of the compressor (50) changes rapidly".

[0246] In the above configuration, it is possible to appropriately perform processing for dealing with the case where the state of the compressor (50) is "a state in which the sealing performance of the compression chamber (68) by the lubricating oil has failed".

[0247] Further, the compression mechanism (65) may have a compression chamber (68) for compressing the working fluid. The compressor (50) may have an oil sump portion (54) where lubricating oil accumulates and an oil supply path (100) for supplying the lubricating oil accumulated in the oil sump portion (54) to the compression chamber (68). The oil supply path (100) has a suction port (101a), and by immersing the suction port (101a) in the lubricating oil accumulated in the oil sump portion (54), it may be possible to supply the lubricating oil sucked from the suction port (101a) to the compression chamber (68). The compression chamber (68) may be sealed with 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 accumulated in the oil sump portion (54).

[0248] As a result of intensive research, the inventor of the present application has found that "when the suction port (101a) of the oil supply path (100) in the compressor (50) is no longer immersed in the lubricating oil accumulated in the oil sump portion (54), the sealing performance of the compression chamber (68) by the lubricating oil fails, and as a result, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes abruptly".

[0249] In the above configuration, it is possible to appropriately perform processing for dealing with the case where 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 sump portion (54)".

[0250] Further, the predetermined state may 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 intensive research, the inventor of the present application has found that "when the liquid working fluid is sucked into the compression mechanism (65) and compressed in the compression mechanism (65) in the compressor (50), a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes abruptly".

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

[0253] Further, the control method of the embodiment relates to a control method for controlling a system including a compressor (50) having a motor (60) and a compression mechanism (65). This control method includes an acquisition step and a countermeasure step. In the acquisition step, a physical quantity correlated with the state of the compressor (50) is acquired. In the countermeasure step, when the relationship between the index value indicating the magnitude of the temporal change of the specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold value becomes a predetermined relationship, 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 the operating conditions of the system is performed.

[0254] In the above method, when the relationship between the index value indicating the magnitude of the temporal change of the specific frequency component included in the physical quantity correlated with the state of the compressor (50) and a predetermined threshold value becomes a predetermined relationship, the countermeasure step is performed, so that it is possible to appropriately perform processing for dealing with the case where the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly).

Industrial Applicability

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

Explanation of Reference Numerals

[0256] 1 Equipment 5 Power supply 10 Drive system 20 Motor drive device 21 Converter 22 DC section 23 Inverter (conversion section) 30 Control device (state estimation device) 31 Control unit 41-phase current detection unit 42 electrical angle frequency detection unit 50 compressor 54 oil sump section 60 motor 65 compression mechanism 68 compression chamber 100 oil supply path 101a suction 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), wherein when the relationship between an 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 a predetermined threshold value becomes a predetermined relationship, a control unit (31) performs a coping process including at least one of an output process for outputting information indicating that the state of the compressor (50) is a predetermined state and a change process for changing the operating conditions of the system Control device.

2. In the control device according to claim 1, under the 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 as 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 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 was derived, the second moving average value (MA2) is set 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 was derived, when the threshold value is set as a value equal to or greater than 1.1 times the maximum value of the index value obtained during 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 coping process when the index value exceeds the threshold value Control device.

3. In the control device according to claim 1, under the 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 as 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 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 was derived, the second moving average value (MA2) is set 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 was derived, when the threshold value is set as 0.1, the control unit (31) performs the coping process when the index value exceeds the threshold value Control device.

4. In the control device according to claim 1, the compression mechanism (65) has a compression chamber (68) for compressing the working fluid, the compression chamber (68) is sealed with lubricating oil, the predetermined state is a state in which the sealing property of the compression chamber (68) by the lubricating oil has failed Control device.

5. In the control device according to claim 1, the compression mechanism (65) has a compression chamber (68) for compressing the working fluid, the compressor (50) has an oil sump portion (54) where lubricating oil accumulates and an oil supply path (100) for supplying the lubricating oil accumulated in the oil sump portion (54) to the compression chamber (68), the oil supply path (100) has a suction port (101a), and by immersing the suction port (101a) in the lubricating oil accumulated in the oil sump portion (54), it becomes possible to supply the lubricating oil sucked from the suction port (101a) to the compression chamber (68), the compression chamber (68) is sealed with 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 sump portion (54) Control device.

6. In the control device according to 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.

7. In the control device according to claim 1, the physical quantity is any one 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 the sound around the compressor (50) Control device.

8. In the control device according to claim 1, the frequency of the specific frequency component is a frequency synchronized with the rotational frequency of the motor (60) Control device.

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

10. A control method for controlling a system including a compressor (50) having a motor (60) and a compression mechanism (65), comprising: an acquisition step of acquiring a physical quantity correlated with the state of the compressor (50) When the relationship between the index value indicating the magnitude of the temporal change of the specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold value becomes a predetermined relationship, 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 the operating conditions of the system is performed. A coping step is provided. Control method.

11. A control program for causing a computer to execute the control method according to claim 10.

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