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] This disclosure relates to control technology. [Background technology]

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

[0003] [Patent Document 1] Patent No. 6173530 [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0005] A first aspect of this disclosure relates to a control method for controlling a system comprising a compressor (50) having a motor (60) and a compression mechanism (65), the control method comprising: an acquisition step of acquiring a physical quantity correlated with the state of the compressor (50); and a handling step of performing at least one of an output step and a change step of changing the operating conditions of the system, wherein the relationship between an index value indicating the magnitude of temporal change of a specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold is a predetermined relationship, the index value When the threshold is defined as the absolute value of the difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1, the first moving average (MA1) is defined as the average of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value was derived, the second moving average (MA2) is defined as the average of 180 amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value was derived, and the threshold is defined as a value of 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 countermeasure step is performed when the index value exceeds the threshold.

[0006] As a result of diligent research, the inventors of this application have discovered that there is a state in which a compressor (50) having a motor (60) and a compression mechanism (65) undergoes a "rapid change in a specific frequency component included in a physical quantity correlated with the state of the compressor (50)." Furthermore, the inventors of this application have discovered that such a state (the state of the compressor (50) where a specific frequency component undergoes a rapid change) can be estimated based on the magnitude of the temporal change in the specific frequency component included in the physical quantity. 。

[0007] Also, As a result of diligent research, the inventors of this application have found that by setting the threshold value for the above-mentioned index value to "a value of 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 a specific frequency component changes rapidly) when the index value exceeds the above-mentioned threshold value.

[0008] The 1 In this configuration, if the above index value exceeds the above threshold, Action steps will be taken. This allows for appropriate processing to be carried out to address situations where the compressor (50) is in a predetermined state (a state in which a specific frequency component changes rapidly).

[0009] A second aspect of the present disclosure relates to a control method for controlling a system comprising a compressor (50) having a motor (60) and a compression mechanism (65), the control method comprising: an acquisition step of acquiring a physical quantity correlated with the state of the compressor (50); and a response step of performing at least one of an output step, in which information indicating that the state of the compressor (50) is in a predetermined state is output when the relationship between an index value indicating the magnitude of temporal change of a specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold is in a predetermined relationship, and a change step of changing the operating conditions of the system, wherein the physical quantity obtained within a period of 10 seconds includes the specific frequency component Under the condition that the amplitude value of a constant frequency component is derived every second, the index value is defined as the absolute difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1, the first moving average (MA1) is defined as the average of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value was derived, the second moving average (MA2) is defined as the average of 180 amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value was derived, and the threshold is set to 0.1. In this case, the countermeasure step is performed when the index value exceeds the threshold.

[0010] As a result of diligent research, the inventors of this application have found that by setting the threshold value for the above-mentioned index value to "0.1", it is possible to estimate that the state of the compressor (50) is in a predetermined state (a state in which a specific frequency component changes rapidly) when the above-mentioned index value exceeds the above-mentioned threshold value.

[0011] The 2 In this configuration, if the above index value exceeds the above threshold, Action steps will be taken. This allows for appropriate processing to be carried out to address situations where the compressor (50) is in a predetermined state (a state in which a specific frequency component changes rapidly).

[0012] A third aspect of the present disclosure is a control method according to the first or second aspect, wherein the compression mechanism (65) has a compression chamber (68) for compressing a working fluid, the compression chamber (68) is sealed with lubricating oil, and the predetermined state is a state in which the sealing performance of the compression chamber (68) by the lubricating oil has failed.

[0013] As a result of intensive research, the inventor of the present application has found 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 abruptly."

[0014] No. 3 In the aspect of, it is possible to appropriately perform a process for dealing with the case where the state of the compressor (50) is "a state where the sealing performance of the compression chamber (68) by the lubricating oil has failed."

[0015] A fourth aspect of the present disclosure is a control method of the first or second aspect, wherein the compression mechanism (65) has a compression chamber (68) for compressing a working fluid, the compressor (50) has an oil reservoir (54) for accumulating lubricating oil, and an oil supply path (100) for supplying the lubricating oil accumulated in the oil reservoir (54) to the compression chamber (68), the oil supply path (100) has a suction port (101a), and the suction port (101a) is immersed in the lubricating oil accumulated in the oil reservoir (54) so ​​that the lubricating oil sucked in from the suction port (101a) can be supplied to the compression chamber (68), the compression chamber (68) is sealed by the lubricating oil, and the predetermined state is a control method in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).

[0016] 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) stops being immersed in the lubricating oil accumulated in the oil reservoir part (54), the sealing performance of the compression chamber (68) by the lubricating oil fails, and as a result, the specific frequency component included in the physical quantity correlated with the state of the compressor (50) changes abruptly."

[0017] No. 4 In the aspect of, it is possible to appropriately perform a process for dealing with the case where 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 reservoir part (54)."

[0018] A fifth aspect of the present disclosure is a control method in the first or second aspect, wherein the predetermined state is a liquid compression state in which a liquid working fluid is drawn into the compression mechanism (65) and compressed in the compression mechanism (65).

[0019] 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) in the compressor (50) and compressed in the compression mechanism (65), the specific frequency component included in the physical quantity correlated with the state of the compressor (50) changes abruptly."

[0020] In the sixth aspect, appropriate processing can be carried out to address the case where the state of the compressor (50) is a "liquid compression state in which a liquid working fluid is drawn into the compression mechanism (65) and compressed in the compression mechanism (65)."

[0021] A sixth aspect of the present disclosure is a control method according to the first or second aspect, wherein the physical quantity is one of the following: 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), or the sound around the compressor (50).

[0022] A seventh aspect of this disclosure is a control method according to the first or second aspect, wherein the frequency of the specific frequency component is synchronized with the rotation frequency of the motor (60).

[0023] An eighth aspect of the present disclosure is a control method of the first or second aspect, wherein the system is a refrigeration system comprising a refrigerant circuit (RR1) including a compressor (50) having a motor (60) and a compression mechanism (65).

[0024] A ninth aspect of this disclosure is a control program that causes a computer to execute a control method according to the first or second aspect. [Brief explanation of the drawing]

[0025] [Figure 1] Figure 1 is a block diagram illustrating the configuration of the drive system according to the embodiment. [Figure 2] Figure 2 is a longitudinal cross-sectional view illustrating the internal structure of a compressor. [Figure 3] Figure 3 is a graph illustrating the relationship between oil volume and specific frequency components. [Figure 4] Figure 4 is a graph illustrating the temporal changes of specific frequency components before and after the occurrence of an oil volume anomaly. [Figure 5] Figure 5 is a graph illustrating the temporal changes of specific frequency components when the oil volume is normal and when the sealing performance of the compression chamber by the lubricating oil fails. [Figure 6] Figure 6 is a graph illustrating the temporal changes of specific frequency components during liquid compression. [Figure 7] Figure 7 is a graph illustrating the temporal changes of a specific frequency component during normal operation and the temporal changes of a specific frequency component when liquid compression occurs. [Figure 8] Figure 8 is a flowchart illustrating the estimation process performed by the control unit. [Figure 9] Figure 9 is a graph illustrating the first estimation process. [Figure 10]Figure 10 is a graph illustrating the second estimation process. [Figure 11] Figure 11 is a graph illustrating the third estimation process. [Figure 12] Figure 12 is a graph illustrating the first and second moving averages. [Figure 13] Figure 13 is a graph illustrating the fourth estimation process. [Figure 14] Figure 14 is a piping diagram illustrating the configuration of a refrigeration system. [Figure 15] Figure 15 is a graph illustrating the derivation of the amplitude values ​​of specific frequency components. [Figure 16] Figure 16 is a graph illustrating the fluctuations in indicator values ​​according to the compressor's condition. [Figure 17] Figure 17 is a graph illustrating the temporal change in torque in a two-cylinder compressor. [Modes for carrying out the invention]

[0026] The embodiments will be described in detail below with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated.

[0027] (Embodiment) Figure 1 illustrates the configuration of the drive system (10) of the embodiment. The drive system (10) drives the motor (60) using power supplied from the power source (5). The motor (60) is mounted on the compressor (50). In addition to the motor (60), the compressor (50) has a compression mechanism (65). The compression mechanism (65) is driven by the motor (60), sucks in a working fluid, compresses it, and discharges the compressed working fluid. For example, the working fluid is a refrigerant.

[0028] In this example, the power supply (5) is a three-phase AC power supply, 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 the equipment (1). For example, the equipment (1) is the outdoor unit of an air conditioner. The drive system (10) comprises a motor drive device (20) and a control device (30).

[0029] [Motor drive device] The motor drive unit (20) drives the motor (60). Specifically, the motor drive unit (20) converts the 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 unit (20) includes a converter (21), a DC unit (22), and an inverter (23).

[0030] The converter (21) rectifies the power supplied from the power source (5). In this example, the converter (21) full-wave rectifies the AC power supplied from the power source (5). For example, the converter (21) is composed of a diode bridge circuit in which multiple rectifier diodes are connected in a bridge configuration.

[0031] The DC section (22) generates DC power corresponding to the power supplied from the power source (5). In this example, the DC section (22) has a capacitor that smooths the output of the converter (21).

[0032] The inverter (23) has multiple switching elements, and the switching operation of the multiple switching elements converts the output of the DC section (22) into output AC power (three-phase AC power) having a predetermined frequency and voltage. The inverter (23) is an example of a conversion unit that converts DC power generated by the DC section (22) into AC power by switching operation.

[0033] In this example, the inverter (23) has six bridge-connected switching elements and six freewheeling diodes connected in antiparallel to each of the six switching elements. More specifically, the inverter (23) has three switching legs, each consisting of two switching elements connected in series. The midpoints of these three switching legs (specifically, the connection points between the switching elements on the upper arm and the switching elements on the lower arm) are connected to the three windings of the motor (60) (U-phase, V-phase, and W-phase windings), respectively.

[0034] [Various sensors] The motor drive unit (20) is equipped with various sensors, such as a phase current detection unit (41) and an electrical angular frequency detection unit (42). Various information detected by the various sensors is transmitted to the control unit (30). Specifically, the detection signals from the various sensors are transmitted to the control unit (31), which will be described later. The various sensors are examples of detection units that detect information for obtaining physical quantities correlated with the state of the compressor (50). In addition, the drive system (10) and the refrigeration system (RR), which will be described later, are also equipped with various sensors for obtaining various physical quantities.

[0035] The phase current detection unit (41) detects the three phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)) flowing through the three windings (not shown) of the motor (60). For example, the phase current detection unit (41) may detect all three phase currents (iu, iv, iw), or it may detect two of the three phase currents (iu, iv, iw) and derive the remaining phase current based on the two detected phase currents. Alternatively, the phase current detection unit (41) may derive the three phase currents (iu, iv, iw) from the DC current detected by the shunt resistor (not shown) provided in the DC unit (22) and the switching pattern.

[0036] 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 a mandatory component; the electrical angular frequency (ω) of the motor (60) may be calculated by other methods or estimated without sensors.

[0037] [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). Furthermore, the processing in the control device (30) (processing related to the control of a system equipped with the compressor (50)) is an example of a control method for controlling a system equipped with the compressor (50).

[0038] In this example, the control device (30) estimates the state of the compressor (50) and performs processing according to the estimated state of the compressor (50). The control device (30) also controls the motor (60). Specifically, the control device (30) controls the motor (60) by controlling the motor drive device (20).

[0039] [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 that information and data. The processing performed by the control unit (31) will be explained in detail later.

[0040] For example, the control unit (31) includes a processor and a memory electrically connected to the processor that stores a program for operating the processor. The various functions of the control unit (31) are realized when the program is executed by the processor. The control unit (31) is an example of a computer, and the above program is an example of a state estimation program and an example of a control program.

[0041] [Processing by the control unit] In this example, the control unit (31) performs estimation processing, control processing, and handling processing.

[0042] [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 a specific frequency component is expressed as the amount of change of the specific frequency component per unit time. In the estimation process, it is estimated whether the state of the compressor (50) is one in which the "specific frequency component is changing rapidly (specifically, rapidly rising or falling)." The estimation process will be explained in detail later.

[0043] [Control Processing] In the control process, the control unit (31) controls the motor drive unit (20) to control the motor (60). Specifically, the control unit (31) receives target command values ​​such as the command value of the electrical angular frequency (ω) of the motor (60), and detection signals from various sensors provided on the motor drive unit (20). Based on the target command values ​​and detection signals from the various sensors, 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).

[0044] [Action taken] In this example, if the control unit (31) estimates in the estimation process that the state of the compressor (50) is in a state where a specific frequency component changes rapidly, it performs a corrective action. The corrective action is a process to address the state of the compressor (50) where a specific frequency component changes rapidly, and includes at least one of an output process that outputs first information indicating that the state of the compressor (50) is in a state where a specific frequency component changes rapidly, and a modification process that changes the operating conditions of the motor (60).

[0045] Examples of output processing include the following first output processing, second output processing, third output processing, and combinations thereof. The first output processing is the process of displaying the first information on a display device (not shown) provided on a remote controller or the like by outputting the first information to the display device. The second output processing is the process of causing the control unit (not shown) that controls the operation of the device (1) to take action to deal with an abnormal condition by outputting the first information to the control unit. The third output processing is the process of uploading the first information to a data storage unit (not shown) on the cloud.

[0046] Examples of modification processes include the following first modification process, second modification process, third modification process, and combinations thereof. The first modification process is the process of stopping the motor (60). The second modification process is the process of accelerating the motor (60). The third modification process is the process of decelerating the motor (60).

[0047] [Compressor details] As shown in Figure 2, the compressor (50) is a fully enclosed scroll compressor. This compressor (50) comprises a casing (51), a motor (60), a compression mechanism (65), a first support (80), and a second support (85). The motor (60), the compression mechanism (65), the first support (80), and the second support (85) are housed in the casing (51).

[0048] <Casing> The casing (51) is a cylindrical sealed container with both ends closed, and its axial direction is vertical. Inside the casing (51), the compression mechanism (65), the first support part (80), the motor (60), and the second support part (85) are arranged in order from top to bottom. An oil reservoir (54) for storing lubricating oil (refrigeration oil) is formed at the bottom of the casing (51).

[0049] The casing (51) has an intake pipe (52) and a discharge pipe (53). The intake pipe (52) passes through the top of the casing (51) and is connected to the compression mechanism (65), leading low-pressure working fluid from outside the compressor (50) to the compression mechanism (65). The discharge pipe (53) passes through the body of the casing (51) and opens into the internal space of the casing (51) (the space below the second support part (85)). After being discharged from the compression chamber (68), the discharge pipe (53) leads the high-pressure working fluid, which has been led into the space below the second support part (85) of the casing (51), to the outside of the compressor (50). With this configuration, the pressure of the high-pressure working fluid discharged from the compression chamber (68) acts on the space below the second support part (85) of the casing (51) (including the oil reservoir part (54)).

[0050] <Motor> The motor (60) has a stator (61) and a rotor (62). The stator (61) is fixed to the body of the casing (51). The rotor (62) is positioned inside the stator (61). A drive shaft (70) is inserted through the rotor (62).

[0051] <First support part> The first support portion (80) comprises a main body portion (81) and a first bearing portion (82). The main body portion (81) is formed in the shape of a thick disc and is fixed to the casing (51). A crank chamber (81a) is formed in the center of the main body portion (81). The crank chamber (81a) is a cylindrical recess that opens to the front surface (top surface in Figure 2) of the main body portion (81). The first bearing portion (82) is formed in the shape of a cylinder that protrudes from the back surface (bottom surface in Figure 2) of the main body portion (81) and is positioned in the center of the main body portion (81). A through hole is formed in the first bearing portion (82) for inserting the drive shaft (70). A first bearing (91), which will be described later, is fitted into this through hole.

[0052] <Second support part> The second support portion (85) comprises a second bearing portion (86) and three legs (87). The second bearing portion (86) is formed in a thick-walled cylindrical shape. A second bearing (92), which will be described later, is fitted into the second bearing portion (86). The legs (87) extend radially from the second bearing portion (86). The ends of the legs (87) of the second support portion (85) are fixed to the body of the casing (51).

[0053] <Compression mechanism> The compression mechanism (65) is a scroll-type fluid machine. The compression mechanism (65) has a fixed scroll (66) and an orbiting scroll (67). The fixed scroll (66) and the orbiting scroll (67) interlock with each other to form a compression chamber (68).

[0054] The fixed scroll (66) comprises a fixed end plate portion (66a), a fixed lap (66b), and an outer peripheral wall portion (66c). The fixed end plate portion (66a) is a relatively thick, flat portion located at the top of the fixed scroll (66). The fixed lap (66b) is formed in a spiral wall shape and protrudes from the front surface (bottom surface in Figure 2) of the fixed end plate portion (66a). The outer peripheral wall portion (66c) is formed to surround the outer periphery of the fixed lap (66b) and protrudes from the front surface (bottom surface in Figure 2) of the fixed end plate portion (66a). The outer peripheral wall portion (66c) is fixed to a first support portion (80) which is fixed to the casing (51). An intake port (sp) is formed in the outer peripheral wall portion (66c), into which an intake tube (52) is inserted. A discharge port (dp) is formed in the fixed end plate portion (66a).

[0055] The orbital scroll (67) comprises an orbital end plate portion (67a), an orbital lap (67b), and a boss portion (67c). The orbital end plate portion (67a) is formed in a generally circular flat plate shape. The orbital lap (67b) is formed in a spiral wall shape and protrudes from the front surface (upper surface in Figure 2) of the orbital end plate portion (67a). The boss portion (67c) is formed in a cylindrical shape and protrudes from the back surface (lower surface in Figure 2) of the orbital end plate portion (67a), and is positioned in the center of the orbital end plate portion (67a). A third bearing (93), which will be described later, is fitted into the boss portion (67c).

[0056] (Drive shaft) The drive shaft (70) comprises a main shaft portion (71) and an eccentric shaft portion (72). The main shaft portion (71) comprises a main journal portion (71a), a secondary journal portion (71b), and an intermediate shaft portion (71c). The drive shaft (70) is arranged in a manner in which the eccentric shaft portion (72) is positioned above the main shaft portion (71).

[0057] In the main shaft section (71), the main journal section (71a), the intermediate shaft section (71c), and the secondary journal section (71b) are arranged in order from one end to the other. The main journal section (71a), the intermediate shaft section (71c), and the secondary journal section (71b) are each formed in a cylindrical shape and are arranged coaxially with each other. The main journal section (71a) has a larger diameter than the intermediate shaft section (71c), and the secondary journal section (71b) has a smaller diameter than the intermediate shaft section (71c). Furthermore, the main journal section (71a) is located above the intermediate shaft section (71c), and the secondary journal section (71b) is located below the intermediate shaft section (71c).

[0058] The main journal section (71a) is inserted inside the first bearing (91), which is fitted into the first bearing section (82) of the first support section (80), and is supported by the first bearing (91). The secondary journal section (71b) is inserted inside the second bearing (92), which is fitted into the second bearing section (86) of the second support section (85), and is supported by the second bearing (92). The intermediate shaft section (71c) is inserted inside the rotor (62) of the motor (60) and is fixed to the rotor (62).

[0059] The eccentric shaft portion (72) is formed in a relatively short shaft shape and protrudes from the end face of the main journal portion (71a). The eccentric shaft portion (72) is located above 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 the third bearing (93) fitted into the boss portion (67c) of the orbiting scroll (67) and is supported by the third bearing (93).

[0060] (bearings) The first bearing (91), the second bearing (92), and the third bearing (93) are all cylindrical and are sliding bearings that support the drive shaft (70).

[0061] The first bearing (91) is fitted inside the first bearing portion (82) of the first support portion (80). The main journal portion (71a) of the drive shaft (70) is inserted into the first bearing (91), and the first bearing (91) supports the main journal portion (71a) of the drive shaft (70).

[0062] The second bearing (92) is fitted inside the second bearing portion (86) of the second support portion (85). The second bearing (92) supports the secondary journal portion (71b) of the drive shaft (70) by having the secondary journal portion (71b) of the drive shaft (70) inserted inside the second bearing (92).

[0063] The third bearing (93) is fitted inside the boss portion (67c) of the orbital scroll (67). The eccentric shaft portion (72) of the drive shaft (70) is inserted into the inside of the third bearing (93), and the eccentric shaft portion (72) of the drive shaft (70) is supported by the third bearing (93).

[0064] (Refueling route) The compressor (50) is provided with an oil supply path (100). The oil supply path (100) is a path (passage) for supplying lubricating oil (refrigeration oil) stored in an oil reservoir (54) formed at the bottom of the casing (51) to the sliding parts. The oil supply path (100) has a main oil supply path (101) and a secondary oil supply path (102).

[0065] The main lubrication passage (101) is formed within the drive shaft (70). The main lubrication passage (101) has a main passage that extends axially from one end of the drive shaft (70) to the other (from the lower end to the upper end in Figure 2), and branch passages that branch off from the main passage toward the sliding portion between the drive shaft (70) and the first bearing (91), the sliding portion between the drive shaft (70) and the second bearing (92), and the sliding portion between the drive shaft (70) and the third bearing (93). The main lubrication passage (101) guides the lubricating oil (refrigeration oil) stored in the oil reservoir (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)).

[0066] The secondary lubrication passage (102) is formed to extend from the first support section (80) to 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)). The secondary lubrication passage (102) is formed so that one end opens in the crank chamber (81a) and the other end opens in the gap between the outer peripheral wall (66c) of the fixed scroll (66) and the orbiting end plate (67a) of the orbiting scroll (67). Lubricating oil is guided from the oil reservoir (54) via the main lubrication passage (101) to the sliding part between the drive shaft (70) and the third bearing (93), and after lubricating that sliding part, the lubricating oil that flows out of that sliding part is stored in the crank chamber (81a). The auxiliary lubrication passage (102) guides the lubricating oil, after it has lubricated the sliding parts of the drive shaft (70) and the third bearing (93), from the crank chamber (81a) to the compression mechanism (65). The lubricating oil guided to the compression mechanism (65) seals the compression chamber (68) (specifically, the gap between the fixed scroll (66) and the orbiting scroll (67)).

[0067] With this configuration, the lubricating oil in the oil reservoir (54), which is subjected to the pressure (high pressure) of the working fluid discharged from the compression mechanism (65), flows into the main oil supply passage (101) via the suction port (101a) of the main oil supply passage (101), flows through the main oil supply passage (101) and is supplied to the sliding parts 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 parts between the drive shaft (70) and the third bearing (93) is stored in the crank chamber (81a) after lubricating the sliding parts between the drive shaft (70) and the third bearing (93). Lubricating oil stored in the crank chamber (81a) is supplied via the auxiliary lubrication passage (102) to the compression chamber (68) of the compression mechanism (65) (specifically, the gap between the fixed scroll (66) and the orbiting scroll (67)), sealing the compression chamber (68).

[0068] [Knowledge obtained by the present inventor] As a result of diligent research, the inventors of this application have found that there is a state in which a compressor (50) having a motor (60) and a compression mechanism (65) undergoes a "rapid change in a specific frequency component included in a physical quantity correlated with the state of the compressor (50)."

[0069] Specifically, the inventors of the present invention have discovered that "when the sealing performance of the compression chamber (68) by lubricating oil in the compressor (50) fails, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes rapidly." In particular, the inventors of the present invention have discovered 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 (54), the sealing performance of the compression chamber (68) by 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."

[0070] Furthermore, the inventors of this application have discovered that when a liquid working fluid is drawn 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 rapidly.

[0071] Furthermore, the inventors of the present invention have found that the above-described state (the state of the compressor (50) in which a 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.

[0072] The findings obtained by the present inventor will be explained in detail below. In the following explanation, we will use the example 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 equal to 1 times the mechanical angular frequency of the motor (60) (hereinafter referred to as the "first-order component")". The "current vector amplitude (Ia)" is an example of a physical quantity correlated with the torque of the compressor (50), and is also an example of a physical quantity correlated with the voltage or current of the motor (60). The mechanical angular frequency of the motor (60) corresponds to the rotational frequency of the motor (60).

[0073] [Failure of sealing performance of the compression chamber (68) due to lubricating oil] First, with reference to Figure 2, the failure of the sealing performance of the compression chamber (68) will be explained. In the compressor (50), when the suction port (101a) of the oil supply path (100) is no longer immersed in the lubricating oil accumulated in the oil reservoir (54), the sealing performance of the compression chamber (68) by the lubricating oil fails, and the amplitude of the torque pulsation of the compressor (50) suddenly decreases. Specifically, the magnitude of the first component of the rotation 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 first component of the rotation frequency of the motor (60) in the current vector amplitude (Ia) suddenly decreases.

[0074] Next, referring to Figures 3 and 4, the changes in specific frequency components in response to changes in the amount of oil accumulated in the oil reservoir (54) will be explained. In the following explanation, "oil amount" refers to the amount of oil accumulated in the oil reservoir (54). "Normal oil amount" means that the suction port (101a) of the oil supply path (100) is immersed in the lubricating oil accumulated in the oil reservoir (54). "Abnormal oil amount" means that the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54).

[0075] As shown in Figure 3, the amplitude value of a specific frequency component gradually decreases as the oil volume gradually decreases. The oil volume changes according to the operating conditions of the compressor (50). As shown in Figure 4, when the oil volume changes from normal to abnormal at time (t1), the amplitude value of a specific frequency component drops sharply.

[0076] As shown in Figures 3 and 4, the amplitude value of a specific frequency component during an abnormal oil level is smaller than the amplitude value of a specific frequency component during an abnormal oil level. Therefore, to distinguish between a normal and abnormal oil level, it is conceivable to compare the magnitude (amplitude value) of a specific frequency component with a threshold value. However, in order to set a threshold value to be compared with the magnitude of a specific frequency component, it is necessary to consider the errors contained in the specific frequency component (sensor errors, errors due to pressure and temperature effects, etc.), which can make it difficult to set the above threshold value appropriately.

[0077] For example, if the median value of a specific frequency component when the oil level is normal (e.g., the median value of the expected range of change) is "1.37A" and the median value of a specific frequency component when the oil level is abnormal is "0.75A", it is desirable to set the threshold for distinguishing between normal and abnormal oil levels between "0.75A" and "1.37A". However, the value of a specific frequency component when the oil level is normal has a range due to errors (sensor errors, errors due to the effects of pressure and temperature, etc.) and the effects of the oil level, and its minimum value is "0.85A". Similarly, the value of a specific frequency component when the oil level is abnormal also has a range due to the effects of errors, and its maximum value is "1.23A". Therefore, it is not possible to set the above threshold appropriately. Note that the reason why the value of a specific frequency component changes due to errors and the effects of the oil level is that the waveform of the physical quantity (a physical quantity correlated with the state of the compressor (50)) changes due to the effects of errors and the oil level.

[0078] As shown in Figure 5, the temporal change of a specific frequency component when the sealing performance of the compression chamber (68) fails due to lubricating oil (temporal change during period (TA) in the example of Figure 5) is significantly larger than the temporal change of a specific frequency component associated with an increase or decrease in oil volume when the oil volume is normal (temporal change during period (TB) in the example of Figure 5). The vertical axis of Figure 5 shows the percentage (ratio to the reference) of the amplitude value of a specific frequency component, with the amplitude value of the specific frequency component at the beginning of period (TB) being the reference (100%). For example, the temporal change of a specific frequency component when the sealing performance of the compression chamber (68) fails due to lubricating oil is a "40% decrease in 30 seconds (1.333% / second)", while the temporal change of a specific frequency component associated with an increase or decrease in oil volume when the oil volume is normal is a "11% decrease in 1800 seconds (0.006% / second)".

[0079] Therefore, based on the magnitude of the temporal change of a specific frequency component, it is possible to identify a sudden change (specifically, a sharp drop) in that specific frequency component when the sealing performance of the compression chamber (68) by the lubricating oil fails. For example, by comparing a value indicating the magnitude of the temporal change of a 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 failed.

[0080] Furthermore, in order to set a threshold that is compared to the magnitude of the temporal change of a specific frequency component, it is not necessary to consider errors contained in the specific frequency component (such as sensor errors, errors due to pressure and temperature influences, etc.). Therefore, it is possible to set the threshold more appropriately than when setting a threshold that is compared to the magnitude of a specific frequency component.

[0081] Specifically, the temporal changes in specific frequency components due to changes in pressure and temperature are sufficiently smaller than the temporal changes in specific frequency components when the sealing performance of the compression chamber (68) fails due to the lubricating oil. Furthermore, the temporal changes in specific frequency components due to changes in pressure and temperature are sufficiently smaller than the difference between "the temporal changes in specific frequency components when the sealing performance of the compression chamber (68) fails due to the lubricating oil" and "the temporal changes in specific frequency components due to increases or decreases in oil volume when the oil volume is normal."

[0082] Furthermore, in order to reduce errors contained in specific frequency components, it is conceivable to prepare separate thresholds for each sensor unit or for each pressure and temperature. However, this method makes the state estimation algorithm complex and increases the computational load, thus increasing the cost of computing units such as processors. On the other hand, in the method in the embodiment (state estimation based on the magnitude of temporal change of specific frequency components), it is sufficient to set only a single threshold for the magnitude of temporal change of specific frequency components, thus suppressing the increase in computational load and allowing the use of existing processors as is.

[0083] Furthermore, in order to understand the influence of oil volume on specific frequency components, it is conceivable to install a separate sensor to detect the oil volume. However, this method would increase costs due to the installation of the sensor. On the other hand, the method in the embodiment (state estimation based on the magnitude of temporal change of specific frequency components) does not require the installation of a separate sensor to detect the oil volume, thus avoiding the increase in costs due to sensor installation.

[0084] Furthermore, the method in the embodiment (state estimation based on the magnitude of temporal changes in specific frequency components) can capture changes in the current waveform when an anomaly occurs by focusing on frequency components. By monitoring by focusing on frequency components in this way, anomalies can be detected with greater accuracy than when monitoring RMS values ​​or average values.

[0085] [Liquid compression] Next, liquid compression will be explained with reference to Figure 6. In the compressor (50), when the liquid working fluid is drawn 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 first component of the rotation frequency of the motor (60) in the torque suddenly increases. Therefore, when liquid compression occurs, the first component of the rotation frequency of the motor (60) in the current vector amplitude (Ia) suddenly increases.

[0086] As shown in Figure 6, when liquid compression occurs at time (t1), the amplitude value of a specific frequency component rises sharply. Subsequently, when the liquid working fluid is removed from the compression mechanism (65), the amplitude value of the specific frequency component returns to its original value.

[0087] Furthermore, as shown in Figure 6, the amplitude value of a specific frequency component during liquid compression is larger than the amplitude value of a specific frequency component during normal operation. Therefore, to distinguish between normal operation and liquid compression, it is conceivable to compare the magnitude (amplitude value) of the specific frequency component with a threshold value. However, in order to set a threshold value to be compared with the magnitude of the specific frequency component, it is necessary to consider the errors contained in the specific frequency component (sensor errors, errors due to the effects of pressure and temperature, etc.), which can make it difficult to set the above threshold value appropriately.

[0088] For example, if the median value of a specific frequency component during normal operation (e.g., the median value of the expected range of change) is "1.37A" and the median value of a specific frequency component during liquid compression is "1.96A", it is desirable to set the threshold for distinguishing between normal operation and liquid compression between "1.37A" and "1.96A". However, the value of the specific frequency component during normal operation has a range due to errors (sensor errors, errors due to pressure and temperature, etc.) and the influence of oil volume, with its maximum value being "1.89A". Similarly, the value of the specific frequency component during liquid compression also has a range due to errors and the influence of oil volume, with its minimum value being "1.44A". Therefore, it is not possible to set the above threshold appropriately.

[0089] As shown in Figure 7, the temporal change of a specific frequency component during liquid compression (temporal change over period (TC) in the example of Figure 7) is significantly larger than the temporal change of a specific frequency component during normal operation (temporal change over period (TD) in the example of Figure 7). The vertical axis of Figure 7 shows the percentage (ratio to the reference) of the amplitude value of a specific frequency component, with the amplitude value of the specific frequency component at the beginning of period (TD) being the reference (100%). For example, the temporal change of a specific frequency component during liquid compression is a "43% increase in 20 seconds (2.15% / sec)", while the temporal change of a specific frequency component during normal operation is an "11% increase or decrease in 1800 seconds (0.006% / sec)".

[0090] Therefore, based on the magnitude of the temporal change in a specific frequency component, it is possible to identify a sudden change (specifically, a sharp rise) in a specific frequency component during liquid compression. For example, by comparing a value indicating the magnitude of the temporal change in a specific frequency component with a threshold value, it is possible to estimate whether or not the state of the compressor (50) is in a "liquid compression state".

[0091] Furthermore, in order to set a threshold that is compared to the magnitude of the temporal change of a specific frequency component, it is not necessary to consider errors contained in the specific frequency component (such as sensor errors, errors due to pressure and temperature influences, etc.). Therefore, it is possible to set the threshold more appropriately than when setting a threshold that is compared to the magnitude of a specific frequency component.

[0092] Specifically, the temporal changes in specific frequency components due to changes in pressure and temperature are sufficiently smaller than the temporal changes in specific frequency components when liquid compression occurs. Furthermore, the temporal changes in specific frequency components due to changes in pressure and temperature are sufficiently smaller than the difference between the temporal changes in specific frequency components when liquid compression occurs and the temporal changes in specific frequency components during normal operation.

[0093] [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 a specific frequency component changes rapidly, 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, a state where a specific frequency component changes rapidly can be described as a state where the amount of change of a specific frequency component per unit time exceeds a predetermined reference amount.

[0094] In this example, the physical quantity is a physical quantity correlated with the torque of the compressor (50). The physical quantity is a physical quantity correlated with the voltage or current of the motor (60). The control unit (31) performs estimation processing based on the signals indicating the physical quantities. Specific examples of signals indicating physical quantities will be explained in detail later.

[0095] Furthermore, in this example, the frequency of the specific frequency component is synchronized with the mechanical angular frequency of the motor (60). In other words, the frequency of the specific frequency component is a frequency corresponding to the mechanical angular frequency of the motor (60). Specifically, the frequency of the specific frequency component is an integer multiple of the mechanical angular frequency of the motor (60), or N / M times the mechanical angular frequency of the motor (60). Note that M and N are integers, and N <Mである。

[0096] In this example, during the estimation process, the control unit (31) estimates whether the state of the compressor (50) is "a state in which the sealing of the compression chamber by lubricating oil has failed." Alternatively, the control unit (31) estimates whether the state of the compressor (50) is "a liquid compression state in which liquid working fluid is drawn into the compression mechanism (65) and compressed in the compression mechanism (65)."

[0097] In other words, in this example, the "state in which a specific frequency component of the compressor (50) changes abruptly" as estimated by the control unit (31) is either "a state in which the sealing performance of the compression chamber by the lubricating oil has failed" or "a liquid compression state in which the liquid working fluid is drawn into the compression mechanism (65) and compressed in the compression mechanism (65)."

[0098] In this example, the "state in which the sealing performance of the compression chamber by lubricating oil has failed" specifically means "the state in which the sealing performance of the compression chamber by lubricating oil has failed because the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54)." The control unit (31) may also estimate whether the state of the compressor (50) is "the state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54)."

[0099] [Estimation Processing Flow] Next, the flow of the estimation process will be explained with reference to Figure 8. The control unit (31) repeatedly performs the following process.

[0100] <Step (S1): Acquisition Step> First, the control unit (31) acquires a physical quantity (for example, current vector amplitude (Ia)) that is correlated with the state of the compressor (50). In this example, the control unit (31) acquires a physical quantity at predetermined derivation time intervals based on information obtained from various sensors (information for obtaining a physical quantity correlated with the state of the compressor (50)). This process is repeated so that a physical quantity is obtained at each derivation time interval.

[0101] Furthermore, the sensor used to acquire "information for obtaining physical quantities correlated with the state of the compressor (50)" in the estimation process may also be used as a sensor used in the control process (for example, a current sensor), or it may be a sensor provided separately from the sensor used in the control process.

[0102] <Step (S2): Estimated 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 first-order component) included in the physical quantity obtained in step (S1). In this example, at predetermined estimation intervals, the control unit (31) derives a value (hereinafter referred to as the "index value") that indicates the magnitude of the temporal change of a specific frequency component included in the physical quantity obtained in step (S1), based on the physical quantity obtained in that physical quantity. The control unit (31) then compares the index value with a threshold and estimates whether the state of the compressor (50) is in a state where the "specific frequency component changes rapidly" according to the result of the comparison. This process is repeated so that an index value is derived at each estimation interval, and the state of the compressor (50) is estimated based on that index value. A specific example of the estimation process will be explained in detail later.

[0103] [Effects of the Embodiment] As described above, in the drive system (10) of the embodiment, the control unit (31) estimates the state of the compressor (50) in the estimation process based on the magnitude of the temporal change of a specific frequency component included in a physical quantity correlated with the state of the compressor (50).

[0104] According to the above configuration, by estimating the state of the compressor (50) based on the magnitude of the temporal change of a specific frequency component, it is possible to estimate whether or not the state of the compressor (50) is in a state where a specific frequency component is rapidly changing.

[0105] Furthermore, 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 in a state where the sealing performance of the compression chamber (68) by lubricating oil has failed.

[0106] According to the above configuration, based on the magnitude of the temporal change of a 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."

[0107] Furthermore, in the drive system (10) of the embodiment, the compression mechanism (65) has a compression chamber (68) for compressing the working fluid. The compressor (50) has an oil reservoir (54) where lubricating oil accumulates and an oil supply path (100) for supplying the lubricating oil accumulated in the oil reservoir (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 reservoir (54), it becomes possible to supply the lubricating oil sucked in from the suction port (101a) to the compression chamber (68). The compression chamber (68) is sealed by the lubricating oil. In the estimation process, the control unit (31) estimates whether the state of the compressor (50) is such that "the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54)".

[0108] According to the above configuration, based on the magnitude of the temporal change of a specific frequency component, it is possible to estimate that the state of the compressor (50) is such that "the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54)."

[0109] Furthermore, in the drive system (10) of the embodiment, the control unit (31) estimates in the estimation process whether the state of the compressor (50) is in a "liquid compression state in which liquid working fluid is drawn into the compression mechanism (65) and compressed in the compression mechanism (65)".

[0110] According to the above configuration, based on the magnitude of the temporal change of a 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 drawn into the compression mechanism (65) and compressed in the compression mechanism (65)."

[0111] (Specific examples of signals indicating physical quantities) Next, we will explain specific examples of "signals that indicate physical quantities correlated with the voltage or current of the motor (60)." These signals are broadly classified into DC signals and AC signals.

[0112] [Specific examples of DC signals] 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)".

[0113] Another example of a DC signal is the current (iγ,iδ) obtained by transforming the phase current (iu,iv,iw) of the motor (60) by its phase (ωi·t), and the voltage (Vγ,Vδ) obtained by transforming the phase voltage (Vu,Vv,Vw) of the motor (60) by its phase (ωv·t). Examples include "the current (iζ,iη) obtained by transforming the phase current (iu,iv,iw) of the motor (60) by the phase (ωv·t) of the phase voltage (Vu,Vv,Vw) of the motor (60)" and "the voltage (Vζ,Vη) obtained by transforming the phase voltage (Vu,Vv,Vw) of the motor (60) by the phase (ωi·t) of the phase current (iu,iv,iw) of the motor (60)".

[0114] Further examples of DC signals include "the dq-axis magnetic flux (λd, λq) whose coordinates have been transformed to match the armature flux linkage of a permanent magnet" and "the magnitude λ0 of the armature flux linkage vector, which is the sum of the armature flux linkage and armature reaction of a permanent magnet."

[0115] In the following explanation, "phase current (iu, iv, iw) of motor (60)" refers to the phase current (iu, iv, iw) of motor (60) detected by the phase current detection unit (41). "phase voltage (Vu, Vv, Vw) of motor (60)" refers to the phase voltage (Vu, Vv, Vw) of motor (60) indicated in the voltage command value used inside the control unit (31), or the phase voltage (Vu, Vv, Vw) of motor (60) detected by the phase voltage detection unit (not shown) provided in the motor drive device (20). "electrical angular frequency (ω) of motor (60)" refers to the electrical angular frequency (ω) of motor (60) detected by the electrical angular frequency detection unit (42).

[0116] [1. Specific examples of signals correlated with the phase current of a motor] Specific examples of signals correlated with the phase currents (iu, iv, iw) of the motor (60) include the current vector amplitude (Ia) and the square of the current vector amplitude (Ia). 2 Examples include the phase current amplitude (I) and the effective value of the phase current (Irms).

[0117] Note that the current vector amplitude (Ia) and the square of the current vector amplitude (Ia) 2 This is an example of a value corresponding to the sum of the squares of each of the three phase currents (iu, iv, iw) of the motor (60). The value corresponding to the sum of the squares of each of the three phase currents (iu, iv, iw) of the motor (60) is an example of a value that is proportional to an integer power of the magnitude of the phase currents (iu, iv, iw) of the motor (60).

[0118] (1) Current vector amplitude The current vector amplitude (Ia) is derived based on the phase currents (iu, iv, iw) of the motor (60). Alternatively, the current vector amplitude (Ia) may be derived based on the α-phase current (iα) and β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (60) into a fixed coordinate system. Alternatively, the current vector amplitude (Ia) may be derived based on the M-axis current (iM) and T-axis current (iT) obtained by transforming the phase currents (iu, iv, iw) of the motor (60) into coordinate systems based on angles determined by the direction of the primary magnetic flux. Alternatively, the current vector amplitude (Ia) may be derived based on the d-axis current (id) and q-axis current (iq) obtained by transforming the phase currents (iu, iv, iw) of the motor (60) into coordinate systems based on angles determined by the direction of the magnetic pole positions. Specifically, the current vector amplitude (Ia) can be expressed by the following equation.

[0119]

number

[0120] (2) Square of the current vector amplitude The square of the current vector amplitude (Ia 2) is derived based on the phase currents (iu, iv, iw) of the motor (60). Also, the square of the current vector amplitude (Ia 2 ) may also 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 a fixed coordinate system. 2 ) may also be derived based on the M-axis current (iM) and T-axis current (iT) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) by an angle based on the direction of the primary magnetic flux. 2 ) may be derived based on the d-axis current (id) and q-axis current (iq) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) by an angle based on the orientation of the magnetic pole positions. Specifically, the square of the current vector amplitude (Ia 2 ) can be expressed as follows:

[0121]

number

[0122] (3) Phase current amplitude The phase current amplitude (I) is derived based on one of the phase currents (iu, iv, iw) of the motor (60) (for example, the U-phase current (iu)) and the phase (ωi) of the phase current. The phase (ωi) of the phase current is derived, for example, based on the phase currents (iu, iv, iw) of the motor (60). Specifically, the phase current amplitude (I) can be expressed by the following equation.

[0123]

number

[0124] (4) RMS value of phase current The effective value of the phase current (Irms) is derived based on the phase current amplitude (I). Specifically, the effective value of the phase current (Irms) can be expressed by the following equation.

[0125] [Number]

[0126] (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) has been 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 squared value (Ia 2 ) of the current vector amplitude.

[0127] [2. Specific examples of signals correlated with the phase voltage of the motor] Specific examples of signals correlated with the phase voltages (Vu, Vv, Vw) of the motor (60) include the voltage vector amplitude (Va), the squared value of the voltage vector amplitude (Va 2 ), the phase voltage amplitude (V), the effective value of the phase voltage (Vrms), etc.

[0128] 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 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 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 voltage (Vu, Vv, Vw) of the motor (60).

[0129] (1) Voltage vector amplitude The voltage vector amplitude (Va) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (60). Alternatively, the voltage vector amplitude (Va) may be derived based on the α-phase voltage (Vα) and β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (60) into a fixed coordinate system. Alternatively, the voltage vector amplitude (Va) may be derived based on the M-axis voltage (VM) and T-axis voltage (VT) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (60) into coordinate systems based on angles determined by the direction of the primary magnetic flux. Alternatively, the voltage vector amplitude (Va) may be derived based on the d-axis voltage (Vd) and q-axis voltage (Vq) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (60) into coordinate systems based on angles determined by the direction of the magnetic pole positions. Specifically, the voltage vector amplitude (Va) can be expressed by the following equation.

[0130]

number

[0131] (2) Square of the voltage vector amplitude The square of the voltage vector amplitude (Va 2 The ) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (60). Also, the square of the voltage vector amplitude (Va 2 ) 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) to a fixed coordinate system. Also, the square of the voltage vector amplitude (Va 2 ) may be derived based on the M-axis voltage (VM) and T-axis voltage (VT) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the direction of the primary magnetic flux. Also, the square of the voltage vector amplitude (Va 2 ) may be derived based on the d-axis voltage (Vd) and q-axis voltage (Vq) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the orientation of the magnetic pole position. Specifically, the square of the voltage vector amplitude (Va 2 ) can be expressed as follows:

[0132]

number

[0133] (3) Phase voltage amplitude The phase voltage amplitude (V) is derived based on one of the phase voltages (Vu, Vv, Vw) of the motor (60) (for example, the U-phase voltage (Vu)) and the phase (ωv) of the phase voltage. The phase (ωv) of the phase voltage is derived, for example, based on the phase voltages (Vu, Vv, Vw) of the motor (60). Specifically, the phase voltage amplitude (V) can be expressed by the following equation.

[0134]

number

[0135] (4) Phase voltage RMS value The phase voltage RMS (Vrms) is derived based on the phase voltage amplitude (V). Specifically, the phase voltage RMS (Vrms) can be expressed by the following equation.

[0136]

number

[0137] (5) Others In the above explanation, we used as an example the case where the voltage vector amplitude (Va) is derived based on the three phase voltages (Vu, Vv, Vw) of the motor (60). However, the voltage vector amplitude (Va) may also be derived based on the phase voltages of two of the three phase voltages (Vu, Vv, Vw) of the motor (60). The square of the voltage vector amplitude (Va 2 The same applies to ).

[0138] [3. Specific examples of signals correlated with motor power] Examples of signals correlated with the power of the motor (60) include instantaneous power (p), instantaneous imaginary power (q), apparent power (S), active power (P), and reactive power (Q).

[0139] (1) Instantaneous power The instantaneous power (p) is derived based on the phase currents (iu, iv, iw) and phase voltages (Vu, Vv, Vw) of the motor (60). Alternatively, 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 a fixed 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 a fixed coordinate system. Furthermore, the instantaneous power (p) may be derived based on the M-axis current (iM) and T-axis current (iT) obtained by 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 transforming the phase voltages (Vu, Vv, Vw) of the motor (60) by an angle based on the direction of the primary magnetic flux. Alternatively, the instantaneous power (p) may be derived based on the d-axis current (id) and q-axis current (iq) obtained by 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 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:

[0140]

number

[0141] (2) Instantaneous imaginary power The instantaneous imaginary 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) to a fixed 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 a fixed coordinate system. Alternatively, the instantaneous imaginary power (q) may be derived based on the M-axis current (iM) and T-axis current (iT) obtained by converting the phase currents (iu, iv, iw) of the motor (60) to an angle based on the direction of the primary magnetic flux, and the M-axis voltage (VM) and T-axis voltage (VT) obtained by converting the phase voltages (Vu, Vv, Vw) of the motor (60) to an angle based on the direction of the primary magnetic flux. Furthermore, the instantaneous imaginary power (q) may be derived based on the d-axis current (id) and q-axis current (iq) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (60) by angles based on the orientation of the magnetic pole positions, and the d-axis voltage (Vd) and q-axis voltage (Vq) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (60) by angles based on the orientation of the magnetic pole positions. Specifically, the instantaneous imaginary power (q) can be expressed by the following equation.

[0142]

number

[0143] (3) Apparent power Apparent power (S) is derived based on the effective phase voltage (Vrms) and the effective phase current (Irms). Specifically, apparent power (S) can be expressed by the following equation:

[0144]

number

[0145] (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 (e.g., U-phase voltage (Vu)) and one phase current (e.g., 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 by the following equation.

[0146]

number

[0147] (5) Reactive power 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, reactive power (Q) can be expressed by the following equation.

[0148]

number

[0149] [4. Current obtained by transforming the phase current using the phase of the phase current] The current (iγ,iδ) obtained by transforming the phase current (iu,iv,iw) of motor (60) by the phase (ωi·t) of motor (60) can be expressed as follows:

[0150]

number

[0151] [5. Voltage obtained by transforming the phase voltage by the phase of the phase voltage] The voltage (Vγ,Vδ) obtained by transforming the phase voltages (Vu,Vv,Vw) of the motor (60) by the phase (ωv·t) of the motor (60) can be expressed as follows:

[0152]

number

[0153] [6. Current obtained by transforming the phase current using the phase of the phase voltage] The current (iζ,iη) obtained by transforming the phase current (iu,iv,iw) of the motor (60) by the phase (ωv·t) of the phase voltage (Vu,Vv,Vw) of the motor (60) can be expressed by the following equation.

[0154]

number

[0155] [7. Voltage obtained by transforming the phase voltage using the phase of the phase current] The voltage (Vζ,Vη) obtained by transforming the phase voltage (Vu,Vv,Vw) of the motor (60) by the phase (ωi·t) of the phase current (iu,iv,iw) of the motor (60) can be expressed by the following equation.

[0156]

number

[0157] [6. Magnitude of dq-axis magnetic flux and armature flux linkage vector] The dq-axis magnetic flux (λd, λq) obtained by coordinate transformation to match the armature flux linkage of a permanent magnet, and the magnitude λ0 of the armature flux linkage vector obtained by combining the armature flux linkage and armature reaction of the permanent magnet, can be expressed by the following equation. In the following equation, "Ld" is the d-axis inductance and "Lq" is the q-axis inductance.

[0158]

number

[0159] [7. Other examples of DC signals] Furthermore, the DC signal may be a DC signal obtained by converting the phase current, phase voltage, line current, and line voltage of the motor (60) into a 3-phase 2-phase signal, and then applying a rotational coordinate transformation. For example, the DC signal may be the d-axis current and q-axis current obtained by rotating the α-axis current and β-axis current obtained by converting the phase current of the motor (60) into a 3-phase 2-phase signal, using an angle based on the direction of the magnetic poles of the rotor of the motor (60). Alternatively, the DC signal may be the M-axis current and T-axis current obtained by rotating the α-axis current and β-axis current using an angle based on the direction of the primary magnetic flux of the rotor of the motor (60).

[0160] Furthermore, the DC signal may also be the power input to the converter (21) of the motor drive device (20), the power output from the converter (21), the power output from the DC 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.

[0161] [Specific examples of AC signals] Examples of AC signals include the phase currents (iu, iv, iw) of the motor (60), the phase voltages (Vu, Vv, Vw) of the motor (60), and the flux linkage of each phase (Ψfu, Ψfv, Ψfw).

[0162] The flux linkages (Ψfu, Ψfv, Ψfw) of each phase can be expressed by the following equations.

[0163]

number

[0164] Another example of an AC signal is the fixed-coordinate current, voltage, and flux linkage obtained by converting the above AC signal from three-phase to two-phase.

[0165] Furthermore, the AC signal may be the line current or line voltage of the motor (60). Alternatively, the AC signal may be a two-phase AC current (e.g., α-axis current and β-axis current) or a two-phase AC voltage obtained by converting a phase current or phase voltage, line current or line voltage from three phases to two phases. The AC current may also be the current flowing between the commercial power system (specifically, the AC power source (5)) and the converter (21) of the motor drive unit (20).

[0166] (Specific example of estimation process) Next, we will explain specific examples of estimation processes. Examples of estimation processes include the following four (Essential Processes 1 to 4). Below, we will explain using an example where the estimation process is performed based on the amplitude of a specific frequency component. In the following explanation, "specific frequency component" refers to the "amplitude value of the specific frequency component."

[0167] Furthermore, below, the 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 the "index value." For example, in the estimation process, the control unit (31) derives the index value at predetermined processing cycles and estimates whether the state of the compressor (50) is in a state where "a specific frequency component changes rapidly" based on the result of comparing the index value with a threshold.

[0168] [First estimation process] First, the first estimation process will be explained with reference to Figure 9. The index value in the first estimation process is a ratio value obtained by dividing the "first filter value (F1) that shows a specific frequency component processed by the first filter" by the "second filter value (F2) that shows a specific frequency component determined by the second filter." The time constant of the second filter is greater than the time constant of the first filter.

[0169] Furthermore, if the time constant of the first filter is too large, there is a risk that the temporal changes (temporal changes over a period of 20 to 30 seconds) of specific frequency components that appear during abnormal conditions (for example, when the sealing performance of the compression chamber (68) fails due to lubricating oil) may not be detected. For this reason, the time constant of the first filter may be set to "less than 21.556 seconds," and specifically to "3.59 seconds."

[0170] Furthermore, if the time constant of the second filter is too small, it will approach the time constant of the first filter, resulting in smaller changes in the index value (the percentage value mentioned above) during abnormal conditions. Conversely, if the time constant of the second filter is too large, the influence of the time changes in the rotational speed, pressure, and temperature of the compressor (50) motor (60) may become significant. For this reason, the time constant of the second filter may be set to, for example, "21.556 seconds or more and 215.56 seconds or less," and specifically to "64.67 seconds."

[0171] In the first estimation process, the control unit (31) determines whether the index value in the first estimation process (in this example, the ratio value obtained by dividing the "first filter value (F1)" by the "second filter value (F2)") falls below a predetermined threshold (in this example, the threshold for detecting a sharp drop in a specific frequency component). If the index value falls below the threshold, the control unit (31) estimates that the state of the compressor (50) is one in which a specific frequency component is rapidly changing (in this example, rapidly dropping). On the other hand, if the index value does not fall below the threshold, the control unit (31) estimates that the state of the compressor (50) is not one in which a specific frequency component is rapidly changing (in this example, rapidly dropping).

[0172] In addition, during the first estimation process, the control unit (31) may estimate whether the state of the compressor (50) is in a state where a specific frequency component is rapidly increasing. In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is in a state where a specific frequency component is rapidly increasing if the index value exceeds a predetermined threshold (a threshold for detecting a rapid increase in a specific frequency component).

[0173] Furthermore, the index value in the first estimation process may be the difference value obtained by subtracting the "second filter value (F2)" from the "first filter value (F1)".

[0174] 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, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically, rapidly decreasing)" if the index value in the first estimation process exceeds a predetermined threshold (a threshold for detecting a rapid decrease in a specific frequency component).

[0175] Alternatively, the index value in the first estimation process may be the difference value obtained by subtracting the "first filter value (F1)" from the "second filter value (F2)". In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically, rapidly decreasing)" if the index value in the first estimation process exceeds a predetermined threshold (a threshold for detecting a rapid decrease in a specific frequency component).

[0176] [Second estimation process] Next, the second estimation process will be explained with reference to Figure 10. The index value in the second estimation process is "the first time (t k From "the first time mean (A1) which is the average value of a specific frequency component within a predetermined period (Ta) ending at )" to "the first time (t k The second time point (t) is time (T) earlier than (t) k-1 This is the difference value obtained by subtracting the "second time-averaged value (A2)," which is the average value of a specific frequency component within a predetermined period (Ta) ending at ).

[0177] Furthermore, if the predetermined time (Ta) is too long, there is a risk that the temporal changes (temporal changes over 20 to 30 seconds) of specific frequency components that appear during abnormal situations (for example, when the sealing performance of the compression chamber (68) fails due to lubricating oil) may not be detected. For this reason, the predetermined period (Ta) may be set to "less than 60 seconds," and specifically to "5 seconds."

[0178] Furthermore, if the time (T) is too short, the change in the indicator value (the difference value mentioned above) during an abnormality will be small. Conversely, if the time (T) is too long, the influence of the time changes in the rotational speed, pressure, and temperature of the compressor (50) motor (60) may become large. For this reason, for example, the time (T) may be set to "60 seconds or more and 600 seconds or less," and specifically to "60 seconds."

[0179] In the second estimation process, the control unit (31) determines whether the index value in the second estimation process (in this example, the difference value obtained by subtracting the second time average value (A2) from the first time average value (A1)) exceeds a predetermined threshold (in this example, a threshold for detecting a sudden rise in a specific frequency component). If the index value exceeds the threshold, the control unit (31) estimates that the state of the compressor (50) is one in which a specific frequency component is rapidly changing (in this example, rapidly rising). On the other hand, if the index value does not exceed the threshold, the control unit (31) estimates that the state of the compressor (50) is not one in which a specific frequency component is rapidly changing (in this example, rapidly rising).

[0180] In addition, during the second estimation process, the control unit (31) may estimate whether the state of the compressor (50) is in a state where a specific frequency component is rapidly decreasing. In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is in a state where a specific frequency component is rapidly decreasing if the index value falls below a predetermined threshold (a threshold for detecting a rapid decrease in a specific frequency component).

[0181] Furthermore, the index value in the second estimation process may be a percentage value obtained by dividing the "first time mean (A1)" by the "second time mean (A2)".

[0182] Alternatively, the index value in the second estimation process may be the difference value obtained by subtracting the first time average value (A1) from the second time average value (A2). In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically rapidly increasing)" if the index value in the second estimation process falls below a predetermined threshold (a threshold for detecting a sudden increase in a specific frequency component).

[0183] Alternatively, the index value in the second estimation process may be a percentage value obtained by dividing the "second time average value (A2)" by the "first time average value (A1)". In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically rapidly increasing)" if the index value in the second estimation process falls below a predetermined threshold (a threshold for detecting a sudden increase in a specific frequency component).

[0184] [Third Estimation Process] Next, the third estimation process will be explained with reference to Figures 11 and 12. The index value in the third estimation process is "a predetermined time (t i The first moving average (MA1), which is the moving average of a specific frequency component within the first period (T1) ending at (for example, the current time), is defined as "a predetermined time (t i This is a ratio value obtained by dividing by the "second moving average (MA2)," which is the moving average of a specific frequency component within the second period (T2) ending at ). The second period (T2) is longer than the first period (T1).

[0185] Furthermore, if the first period (T1) is too long, there is a risk that the temporal changes (temporal changes over 20 to 30 seconds) of specific frequency components that appear during abnormal situations (for example, when the sealing performance of the compression chamber (68) fails due to lubricating oil) may not be detected. For this reason, the first period (T1) may be set to "less than 60 seconds," and specifically to "10 seconds."

[0186] Furthermore, if the second period (T2) is too short, the change in the indicator value (the percentage value mentioned above) during an abnormality will be small. Conversely, if the second period (T2) is too long, the influence of the temporal changes in the rotational speed, pressure, and temperature of the compressor (50) motor (60) may become large. For this reason, the second period (T2) may be set to "60 seconds or more and 600 seconds or less," and specifically to "180 seconds."

[0187] In the third estimation process, the control unit (31) determines whether 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 (in this example, the threshold for detecting a sudden rise in a specific frequency component). If the index value exceeds the threshold, the control unit (31) estimates that the state of the compressor (50) is "a state in which a specific frequency component is changing rapidly (in this example, rising rapidly)". On the other hand, if the index value does not exceed the threshold, the control unit (31) estimates that the state of the compressor (50) is not "a state in which a specific frequency component is changing rapidly (in this example, rising rapidly)".

[0188] In addition, during the third estimation process, the control unit (31) may estimate whether the state of the compressor (50) is in a state where a specific frequency component is rapidly decreasing. In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is in a state where a specific frequency component is rapidly decreasing if the index value falls below a predetermined threshold (a threshold for detecting a rapid decrease in a specific frequency component).

[0189] The index value in the third estimation process may be the difference obtained by subtracting the "second moving average (MA2)" from the "first moving average (MA1)".

[0190] Alternatively, the index value in the third estimation process may be a percentage value obtained by dividing the "second moving average value (MA2)" by the "first moving average value (MA1)". In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically, rapidly increasing)" if the index value in the third estimation process falls below a predetermined threshold (a threshold for detecting a sudden increase in a specific frequency component).

[0191] Alternatively, the index value in the third estimation process may be the difference obtained by subtracting the first moving average value (MA1) from the second moving average value (MA2). In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically rapidly increasing)" if the index value in the third estimation process falls below a predetermined threshold (a threshold for detecting a sudden increase in a specific frequency component).

[0192] [Fourth Estimation Process] Next, the fourth estimation process will be explained with reference to Figure 13. The index value in the fourth estimation process is "a predetermined time (t i ) (for example, the instantaneous value (X) of a specific frequency component at the current time) is defined as "a predetermined time (t i This is a ratio value obtained by dividing by the average value (AA) of a specific frequency component within a predetermined period (Tb) ending at ).

[0193] If the predetermined period (Tb) is too short, the change in the indicator value (the difference value mentioned above) during an abnormality will be small. Conversely, if the predetermined period (Tb) is too long, the influence of the temporal changes in the rotational speed, pressure, and temperature of the compressor (50) motor (60) may become large. For this reason, the predetermined period (Tb) may be set to "60 seconds or more and 600 seconds or less," and specifically to "180 seconds."

[0194] In the fourth estimation process, the control unit (31) determines whether the index value in the fourth estimation process (in this example, the ratio value obtained by dividing the "instantaneous value (X)" by the "average value (AA)") falls below a predetermined threshold (in this example, the threshold for detecting a sharp drop in a specific frequency component). If the index value falls below the threshold, the control unit (31) estimates that the state of the compressor (50) is one in which a "specific frequency component is changing rapidly (in this example, dropping rapidly)". On the other hand, if the index value does not fall below the threshold, the control unit (31) estimates that the state of the compressor (50) is not one in which a "specific frequency component is changing rapidly (in this example, dropping rapidly)".

[0195] In addition, during the fourth estimation process, the control unit (31) may estimate whether the state of the compressor (50) is in a state where a specific frequency component is rapidly increasing. In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is in a state where a specific frequency component is rapidly increasing if the index value exceeds a predetermined threshold (a threshold for detecting a rapid increase in a specific frequency component).

[0196] Furthermore, the index value in the fourth estimation process may be the difference value obtained by subtracting the mean value (AA) from the instantaneous value (X).

[0197] Alternatively, the index value in the fourth estimation process may be a percentage value obtained by dividing the "average value (AA)" by the "instantaneous value (X)". In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically, rapidly decreasing)" when the index value in the fourth estimation process exceeds a predetermined threshold (a threshold for detecting a rapid drop in a specific frequency component).

[0198] Alternatively, the index value in the fourth estimation process may be the difference value obtained by subtracting the instantaneous value (X) from the average value (AA). In this case, for example, the control unit (31) may estimate that the state of the compressor (50) is "a state in which a specific frequency component is rapidly changing (specifically, rapidly decreasing)" if the index value in the fourth estimation process exceeds a predetermined threshold (a threshold for detecting a rapid decrease in a specific frequency component).

[0199] (Refrigeration system) Figure 14 illustrates the configuration of a refrigeration system (RR). The refrigeration system (RR) comprises a refrigerant circuit (RR1) filled with refrigerant, a motor drive unit (20), and a control unit (30).

[0200] The refrigerant circuit (RR1) includes a compressor (50), a heat exchanger (RR5), a pressure reducing mechanism (RR6), and an evaporator (RR7). In this example, the pressure reducing mechanism (RR6) is an expansion valve. The refrigerant circuit (RR1) performs a vapor compression type refrigeration cycle.

[0201] The compressor (50) comprises 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) rotates the compression mechanism (65) by rotating the drive shaft. The motor drive device (20) drives the motor (60).

[0202] In the refrigeration cycle, the refrigerant discharged from the compressor (50) dissipates heat in the radiator (RR5). The refrigerant discharged from the radiator (RR5) is depressurized in the depressurization mechanism (RR6) and evaporates in the evaporator (RR7). The refrigerant discharged from the evaporator (RR7) then flows back into the compressor (50).

[0203] 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. Alternatively, the air conditioner may be a unit that switches between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., a four-way directional valve) that switches the direction of refrigerant circulation. The refrigeration system (RR) may also be a water heater, chiller unit, or cooling device that cools the air inside a storage unit. The cooling device cools the air inside a refrigerator, freezer, container, etc.

[0204] (Insights obtained from experiments) Next, with reference to Figures 15 and 16, the experiments conducted by the present inventors and the findings obtained from those experiments will be described.

[0205] As shown in Figure 15, in the experiment, the "amplitude value of a specific frequency component" contained in the physical quantity obtained over a 10-second period (in this example, the current vector amplitude (Ia)) was derived every second. The absolute value of the difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1 was defined as the "index value". The index value can be expressed by the formula "|1-(MA1 / MB2)|". The above index value can be said to be a modified version of the index value in the third estimation process.

[0206] The first moving average (MA1) is the average of 10 amplitude values ​​derived within the first period (T1), which is a 10-second period ending at the time (ti) when the latest amplitude value was derived. The second moving average (MA2) is the average of 180 amplitude values ​​derived within the second period (T2), which is a 3-minute period ending at the time (ti) when the latest amplitude value was derived. For example, the first period (T1) and the second period (T2) can be illustrated as shown in Figure 12.

[0207] Furthermore, in the experiment, the compressor (50) was set to a predetermined "steady state." The steady state of the compressor (50) is a state that is not a predetermined state (a state in which specific frequency components change rapidly), 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.

[0208] (1) The intake port (101a) of the oil supply route (100) is immersed in the lubricating oil accumulated in the oil reservoir (54) (2) The gaseous working fluid is drawn 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 drawn 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 drawn into the compressor (50) is in a steady state. The above steady-state conditions may be determined based on the intended use of the compressor (50), etc.

[0209] As shown in Figure 16, the index value observed when the compressor (50) was in a steady state was below "0.1". When the compressor (50) moved from a steady state to a predetermined state (a state in which a specific frequency component changes rapidly), the index value rose above "0.1" to its maximum value (for example, around 3.5). Furthermore, even when the compressor (50) was in a steady state, the index value fluctuated slightly. By observing the index value included in a 10-minute measurement period, it was possible to observe the peak (maximum value) of the slight fluctuation in the index value.

[0210] Furthermore, in order to verify the effect of individual differences in the compressors (50), the compressor (50) installed in the refrigeration system (RR) was replaced with another compressor (50) (a compressor (50) of the same model), and the above index value was repeatedly observed. As a result, the index value when the compressor (50) was in a steady state was below "0.1" regardless of individual differences in the compressors (50).

[0211] Through the above experiments, the inventors of this invention obtained the following findings. In the following, the "verification conditions" refer to the following conditions under which the amplitude values ​​of specific frequency components included in a physical quantity obtained within a 10-second period are derived every second, the average of the 10 amplitude values ​​derived within a 10-second period (T1) ending at the time (ti) when the latest amplitude value is derived is defined as the "first moving average value (MA1)", the average of the 180 amplitude values ​​derived within a 3-minute period (T2) ending at the time (ti) when the latest amplitude value is derived is defined as the "second moving average value (MA2)", and 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".

[0212] The inventors of the present invention have found that, under the above verification conditions, by setting the threshold for the above index value to "a value of 1.1 times or more the maximum value of the index obtained during a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state" or "0.1", it is possible to estimate that the state of the compressor (50) is a predetermined state (a state in which a specific frequency component changes rapidly) when the above index value exceeds the above threshold.

[0213] Furthermore, by setting the threshold for the index value in each of the first to fourth estimation processes as follows, the corrective action can be performed at the same timing as when the threshold for the above index value (the absolute difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1) is set to "0.1". In the following, the index value that is "the absolute difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1" will be referred to as the "reference index value".

[0214] [Threshold for index value in the first estimation process] If the index value is "the percentage value obtained by dividing the first filter value (F1) by the second filter value (F2)", the threshold is set to "a range from 0.89 to 1.11". If this index value deviates from the above range, the reference index value will exceed "0.1".

[0215] Furthermore, if the index value is "the absolute value of the difference between the ratio 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."

[0216] [Threshold for index value in the second estimation process] If the index value is "the difference obtained by subtracting the second time-average value (A2) from the first time-average value (A1)," the threshold is set to "a range of -0.25 to +0.25." If this index value deviates from the above range, the baseline index value will exceed "0.1."

[0217] [Threshold for index values ​​in the third estimation process] If the index value is "the ratio obtained by dividing the first moving average (MA1) by the second moving average (MA2)," the threshold is set to "a range from 0.9 to 1.1." If this index value deviates from the above range, the baseline index value will exceed "0.1."

[0218] [Threshold for index values ​​in the fourth estimation process] If the index value is "a ratio obtained by dividing the instantaneous value (X) of a specific frequency component by the average value (AA) of that specific frequency component within a predetermined period (Tb)," the threshold is set to "a range of 0.69 to 1.31." 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 instantaneous value (X) of a specific frequency component by the average value (AA) of the specific frequency component within a predetermined period (Tb) and 1", 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".

[0220] (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 to this. 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 within the audible range or outside the audible range (ultrasonic). 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).

[0221] Also, in the above description, the control unit (31) may be configured to perform the estimation process using an algorithm (an algorithm for estimating the state based on the change of the signal) constructed by a neural network or machine learning.

[0222] 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.

[0223] Furthermore, although the above explanation uses the case where the compressor (50) is a "scroll compressor" as an example, it is not limited to this. For example, the compressor (50) may be a swing compressor in which the piston and blades are formed as one unit, a rotary compressor in which the piston and blades are formed separately, or any other type of rotary compressor.

[0224] Furthermore, the compressor (50) may be a two-cylinder type compressor having two compression chambers (swing compressor or rotary compressor).

[0225] As shown in Figure 17, the torque pulsation period of a two-cylinder compressor (pulsation period during normal operation) corresponds to a period that is half the rotation period of the motor (60). Furthermore, in a two-cylinder compressor, when liquid compression occurs, a sudden change in the compressor torque occurs with a period that corresponds to half the rotation period of the motor (60). Therefore, in a two-cylinder compressor, when liquid compression occurs, the second-order component of the compressor (50) torque changes abruptly (specifically, rises sharply), and as a result, the second-order component of the current vector amplitude (Ia) changes abruptly (specifically, rises sharply). Note that the "second-order component" refers to the frequency component having a frequency twice that of the mechanical angular frequency of the motor (60).

[0226] If the compressor (50) is a "two-cylinder type compressor," the "specific frequency component processed in the estimation process" may also be a "second-order component." This makes it possible to estimate whether or not the state of the compressor (50) is a "liquid compression state."

[0227] Furthermore, in the above description, the various sensors may be contact-type sensors or non-contact-type sensors. Contact-type sensors may be attached to the casing (51) of the compressor (50), or to piping or electrical wires located near the compressor (50). Non-contact-type sensors may be attached to a location close to the casing (51) of the compressor (50), a location close to piping or electrical wires located near the compressor (50), or a location close to the equipment (1) on which the compressor (50) is mounted.

[0228] Furthermore, 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 multiple sensors.

[0229] Furthermore, in the above description, the modification process may also be a "modification process that changes the operating conditions of the system equipped with the compressor (50)." In the modification process, not only the operating conditions of the motor (60) may be changed, but also the operating conditions of "other components other than the motor (60)" included in the system equipped with the compressor (50). Examples of modification processes include stopping the motor (60), accelerating the motor (60), decelerating the motor (60), reducing the current flowing through the motor (60), increasing the current flowing through the motor (60), increasing the opening of the expansion valve (electric valve) constituting the pressure reducing mechanism (RR6), decreasing the opening of the expansion valve (electric valve) constituting the pressure reducing mechanism (RR6), increasing the pressure of the working fluid discharged from the compressor (50), decreasing the pressure of the working fluid discharged from the compressor (50), increasing the temperature of the working fluid discharged from the compressor (50), decreasing the temperature of the working fluid discharged from the compressor (50), returning the lubricating oil flowing through the fluid passage with the working fluid to the compressor (50), increasing the rotational speed of the fan (not shown) that transports air to the radiator (RR5) or evaporator (RR7), and decreasing the rotational speed of the fan that transports air to the radiator (RR5) or evaporator (RR7).

[0230] Furthermore, while embodiments and modifications 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. In addition, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate.

[0231] (Summary of the embodiments) To summarize the above description, the control device of the embodiment relates to a control device for controlling a system comprising a compressor (50) having a motor (60) and a compression mechanism (65). This control device comprises a control unit (31). The control unit (31) performs a response process that includes at least one of the following: an output process that outputs information indicating that the state of the compressor (50) is in a predetermined state, and a change process that changes the operating conditions of the system, when the relationship between an index value indicating the magnitude of temporal change of a specific frequency component included in a physical quantity correlated with the state of the compressor (50) and a predetermined threshold is in a predetermined relationship.

[0232] As a result of diligent research, the inventors of this application have discovered that there is a state in which a compressor (50) having a motor (60) and a compression mechanism (65) undergoes a "rapid change in a specific frequency component included in a physical quantity correlated with the state of the compressor (50)." Furthermore, the inventors have discovered that such a state (the state of the compressor (50) where a specific frequency component undergoes a rapid change) can be estimated based on the magnitude of the temporal change in the specific frequency component included in the physical quantity.

[0233] In the above configuration, by performing a corrective action 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 is a predetermined relationship, it is possible to appropriately perform a corrective action when the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly).

[0234] Furthermore, the control unit (31) may be configured to perform corrective action when the index value exceeds the threshold value, under the condition that the amplitude values ​​of specific frequency components included in the physical quantity obtained within a 10-second period are derived every second, with the index value being defined as "the absolute value of the difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1", the first moving average (MA1) being defined as "the average of 10 amplitude values ​​derived within a 10-second first period (T1) ending at the time (ti) when the latest amplitude value was derived", the second moving average (MA2) being defined as "the average of 180 amplitude values ​​derived within a 3-minute second period (T2) ending at the time (ti) when the latest amplitude value was derived", and the threshold being "a value of 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".

[0235] As a result of diligent research, the inventors of this application have found that by setting the threshold value for the above-mentioned index value to "a value of 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 a specific frequency component changes rapidly) when the index value exceeds the above-mentioned threshold value.

[0236] In the above configuration, by performing corrective action when the above indicator value exceeds the above threshold, appropriate processing can be carried out to address the situation when the state of the compressor (50) is in a predetermined state (a state in which a specific frequency component changes rapidly).

[0237] Furthermore, the control unit (31) may be configured to perform corrective action when the index value exceeds the threshold, under the condition that the amplitude values ​​of specific frequency components included in a physical quantity obtained within a 10-second period are derived every second, with the index value being defined as "the absolute value of the difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1", the first moving average (MA1) being defined as "the average of 10 amplitude values ​​derived within a first period (T1) of 10 seconds ending at the time (ti) when the latest amplitude value was derived", the second moving average (MA2) being defined as "the average of 180 amplitude values ​​derived within a second period (T2) of 3 minutes ending at the time (ti) when the latest amplitude value was derived", and the threshold being set to "0.1".

[0238] As a result of diligent research, the inventors of this application have found that by setting the threshold value for the above-mentioned index value to "0.1", it is possible to estimate that the state of the compressor (50) is in a predetermined state (a state in which a specific frequency component changes rapidly) when the above-mentioned index value exceeds the above-mentioned threshold value.

[0239] In the above configuration, by performing corrective action when the above indicator value exceeds the above threshold, appropriate processing can be carried out to address the situation when the state of the compressor (50) is in a predetermined state (a state in which a specific frequency component changes rapidly).

[0240] Furthermore, 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. A predetermined state may be a state in which the sealing performance of the compression chamber (68) by the lubricating oil has failed.

[0241] As a result of diligent research, the inventors of this application have discovered the phenomenon that "when the sealing performance of the compression chamber (68) by lubricating oil in the compressor (50) fails, a specific frequency component included in a physical quantity correlated with the state of the compressor (50) changes rapidly."

[0242] In the above configuration, it is possible to appropriately perform a process 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".

[0243] Further, the compression mechanism (65) may have a compression chamber (68) for compressing the working fluid. The compressor (50) may have an oil reservoir portion (54) where lubricating oil accumulates and an oil supply path (100) for supplying the lubricating oil accumulated in the oil reservoir 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 reservoir 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 by the lubricating oil. The predetermined state may be a state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir portion (54).

[0244] 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 reservoir 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 rapidly".

[0245] In the above configuration, it is possible to appropriately perform a process 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 reservoir portion (54)".

[0246] 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).

[0247] 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 rapidly".

[0248] In the above configuration, it is possible to appropriately handle the case when the state of the compressor (50) is "a liquid compression state in which a liquid working fluid is drawn into the compression mechanism (65) and compressed in the compression mechanism (65)".

[0249] Furthermore, the control method of the embodiment relates to a control method for controlling a system comprising a compressor (50) having a motor (60) and a compression mechanism (65). This control method comprises an acquisition step and a response step. In the acquisition step, a physical quantity correlated with the state of the compressor (50) is acquired. In the response step, at least one of an output step is performed, which outputs information indicating that the state of the compressor (50) is in a predetermined state when the relationship between an index value indicating the magnitude of temporal change of a specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold is a predetermined relationship, and a change step is performed, which changes the operating conditions of the system.

[0250] In the above method, a corrective step is performed 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 is a predetermined relationship. This allows for appropriate processing to be carried out when the state of the compressor (50) is a predetermined state (a state in which the specific frequency component changes rapidly). [Industrial applicability]

[0251] As explained above, this disclosure is useful as a control technology. [Explanation of symbols]

[0252] 1 equipment 5 Power supply 10 Drive System 20 Motor drive unit 21 Converters 22 DC section 23 Inverter (Conversion Unit) 30 Control device (state estimation device) 31 Control Unit 41 Phase current detection unit 42 Electrical angular frequency detection unit 50 Compressors 54 Oil reservoir 60 motor 65 Compression mechanism 68 Compression Chamber 100 Refueling Route 101a Inlet RR Refrigeration System RR1 Refrigerant Circuit

Claims

1. A control method for controlling a system comprising a compressor (50) having a motor (60) and a compression mechanism (65), An acquisition step to acquire a physical quantity correlated with the state of the compressor (50), The system includes an output step, which outputs information indicating that the state of the compressor (50) is in a predetermined state, and a change step, which performs at least one of the following: an output step, which outputs information indicating that the state of the compressor (50) is in a predetermined state, when the relationship between an index value indicating the magnitude of temporal change of a specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold is a predetermined relationship, and a change step, which changes the operating conditions of the system. 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 aforementioned index value is defined as the absolute difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1. The first moving average value (MA1) is defined as the average of the 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 (MA2) is defined as the average of 180 amplitude values ​​derived within a 3-minute second period (T2) ending at the time (ti) when the latest amplitude value was derived. When the threshold is set to a value of 1.1 times or more the maximum value of the index obtained during a 10-minute measurement period under the condition that the compressor (50) is in a predetermined steady state, The aforementioned action step is performed when the index value exceeds the threshold. Control method.

2. A control method for controlling a system comprising a compressor (50) having a motor (60) and a compression mechanism (65), An acquisition step to acquire a physical quantity correlated with the state of the compressor (50), The system includes an output step, which outputs information indicating that the state of the compressor (50) is in a predetermined state, and a change step, which performs at least one of the following: an output step, which outputs information indicating that the state of the compressor (50) is in a predetermined state, when the relationship between an index value indicating the magnitude of temporal change of a specific frequency component included in the physical quantity acquired in the acquisition step and a predetermined threshold is a predetermined relationship, and a change step, which changes the operating conditions of the system. 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 aforementioned index value is defined as the absolute difference between the value obtained by dividing the first moving average (MA1) by the second moving average (MA2) and 1. The first moving average value (MA1) is defined as the average of the 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 (MA2) is defined as the average of 180 amplitude values ​​derived within a 3-minute second period (T2) ending at the time (ti) when the latest amplitude value was derived. When the threshold is set to 0.1, The aforementioned action step is performed when the index value exceeds the threshold. Control method.

3. In the control method of claim 1 or 2, 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 performance of the compression chamber (68) by the lubricating oil has failed. Control method.

4. In the control method of claim 1 or 2, The compression mechanism (65) has a compression chamber (68) for compressing the working fluid, The compressor (50) has an oil reservoir (54) where lubricating oil accumulates, and an oil supply path (100) for supplying the lubricating oil accumulated in the oil reservoir (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 reservoir (54), it becomes possible to supply the lubricating oil sucked in from the suction port (101a) to the compression chamber (68). The compression chamber (68) is sealed by the lubricating oil, The predetermined state is a state in which the suction port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil reservoir (54). Control method.

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

6. In the control method of claim 1 or 2, The physical quantity is one of the following: 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), or the sound around the compressor (50). Control method.

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

8. In the control method of claim 1 or 2, The system is a refrigeration system comprising a refrigerant circuit (RR1) including a compressor (50) having a motor (60) and a compression mechanism (65). Control method.

9. A control program that causes a computer to execute the control method of claim 1 or 2.

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