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

Abstract

In a system provided with a compressor (50) having a motor (60) and a compression mechanism (65), a control unit (31) performs a response process when the relationship between an index value indicating the magnitude of a specific frequency component included in a physical quantity related to the state of the compressor (50) over time and a predetermined threshold value becomes a predetermined relationship. The response process includes at least one of an output process for outputting information indicating that the state of the compressor (50) is a predetermined state and a change process for changing the operating condition of the system.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to control technology. BACKGROUND

[0002] A failure symptom detection device of an air conditioner is disclosed in Patent Literature 1, the air conditioner is provided with a compressor including a motor and a driving device that outputs a three-phase current to the motor. The failure symptom detection device is provided with a conversion section and an abnormality detection section. The conversion section calculates a q-axis current of the motor in accordance with a measured value of the three-phase current and a rotational angle of a rotor of the motor. The abnormality detection section compares an evaluation value calculated by frequency analyzing the q-axis current with a reference value, thereby detecting an abnormality of the compressor.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent No. 6173530 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In a state of a compressor having a motor and a compression mechanism, there is a state in which a specific frequency component included in a physical quantity related to a state of the compressor changes sharply. However, as in Patent Literature 1, only the magnitude of the specific frequency component is compared with a threshold value, and sometimes it is difficult to appropriately perform processing for coping with a case where the state of the compressor is a prescribed state (a state in which the specific frequency component included in the physical quantity changes sharply).

[0008] MEANS FOR SOLVING THE PROBLEMS

[0009] A first aspect of the present disclosure relates to a control device that controls a system provided with a compressor 50 having a motor 60 and a compression mechanism 65, the control device being provided with a control section 31 that performs coping processing in a case where a relationship between an index value indicating a magnitude of a change over time of a specific frequency component included in a physical quantity related to a state of the compressor 50 and a threshold value determined in advance becomes a prescribed relationship, the coping processing including at least one of output processing of outputting information indicating that the state of the compressor 50 is a prescribed state and change processing of changing an operation condition of the system.

[0010] The inventors of the present application conducted intensive research and as a result found that there is a state in which a specific frequency component included in a physical quantity related to the state of the compressor 50 changes sharply in the state of the compressor 50 having the motor 60 and the compression mechanism 65. Further, the inventors of the present application found that such a state (the state of the compressor 50 in which the specific frequency component changes sharply) can be inferred based on the magnitude of the change over time of the specific frequency component included in the physical quantity.

[0011] In the first mode, the coping process is performed when the relationship between the index value indicating the magnitude of the change over time of the specific frequency component included in the physical quantity related to the state of the compressor 50 and the predetermined threshold value becomes a prescribed relationship, and thus the process for coping with the case where the state of the compressor 50 is the prescribed state (the state in which the specific frequency component changes sharply) can be appropriately performed.

[0012] The second mode of the present disclosure is a control device in which, on the basis of the control device of the first mode, in the case where the index value is set to a value obtained by dividing a first moving average value MA1 by a second moving average value MA2, and the absolute value of the difference between 1 and the value, the first moving average value MA1 is set to an average value of 10 amplitude values of the specific frequency component included in the physical quantity obtained in a period of 10 seconds within a first period T1 of 10 seconds ending at the time ti at which the latest amplitude value is derived, the second moving average value MA2 is set to an average value of 180 amplitude values of the specific frequency component included in the physical quantity obtained in a second period T2 of 3 minutes ending at the time ti at which the latest amplitude value is derived, and the threshold value is set to a value of 1.1 times or more of the maximum value of the index value obtained in a measurement period of 10 minutes on the condition that the compressor 50 is in a predetermined stable state, the control section 31 performs the coping process in the case where the index value exceeds the threshold value.

[0013] The inventors of the present application conducted intensive research and as a result found that by setting the threshold value for the above-described index value to "a value of 1.1 times or more of the maximum value of the index value obtained in a measurement period of 10 minutes on the condition that the compressor 50 is in a predetermined stable state", in the case where the above-described index value exceeds the above-described threshold value, it can be inferred that the state of the compressor 50 is the prescribed state (the state in which the specific frequency component changes sharply).

[0014] In the second mode, by performing the coping process in the case where the above-described index value exceeds the above-described threshold value, the process for coping with the case where the state of the compressor 50 is the prescribed state (the state in which the specific frequency component changes sharply) can be appropriately performed.

[0015] The third aspect of the present disclosure is a control device in which, on the basis of the control device of the first aspect, under the condition that the amplitude value of the specific frequency component included in the physical quantity obtained over a period of 10 seconds is derived every 1 second, the control section 31 performs the response process in a case where the index value exceeds the threshold value, in a case where the threshold value is set to 0.1, the index value is set to a value obtained by dividing a first moving average value MA1 by a second moving average value MA2, the first moving average value MA1 is set to an average value of 10 amplitude values derived over a first period T1 of 10 seconds ending at a time ti at which the latest amplitude value is derived, the second moving average value MA2 is set to an average value of 180 amplitude values derived over a second period T2 of 3 minutes ending at the time ti at which the latest amplitude value is derived, and the threshold value is set to 0.1.

[0016] The inventors of the present application have conducted intensive research and as a result, have found that by setting the threshold value for the index value to "0.1", it is possible to infer that the state of the compressor 50 is a prescribed state (a state in which the specific frequency component changes sharply) in a case where the index value exceeds the threshold value.

[0017] In the third aspect, by performing the response process in a case where the index value exceeds the threshold value, it is possible to appropriately perform processing for responding to a case where the state of the compressor 50 is a prescribed state (a state in which the specific frequency component changes sharply).

[0018] The fourth aspect of the present disclosure is a control device in which, on the basis of the control device of any one of the first to third aspects, the compressor 65 has a compression chamber 68 for compressing a working fluid, the compression chamber 68 is sealed by lubricating oil, and the prescribed state is a state in which the sealing performance of the lubricating oil with respect to the compression chamber 68 is lost.

[0019] The inventors of the present application have conducted intensive research and as a result, have found the phenomenon that "when the sealing performance of the lubricating oil with respect to the compression chamber 68 is lost in the compressor 50, the specific frequency component included in the physical quantity related to the state of the compressor 50 changes sharply".

[0020] In the fourth aspect, it is possible to appropriately perform processing for responding to a case where the state of the compressor 50 is a "state in which the sealing performance of the lubricating oil with respect to the compression chamber 68 is lost".

[0021] The fifth aspect of the present disclosure is a control device in which, on the basis of the control device of any one of the first to third aspects, the compression mechanism 65 has a compression chamber 68 for compressing a working fluid, the compressor 50 has an oil storage portion 54 that stores lubricating oil, and an oil supply path 100 for supplying the lubricating oil stored in the oil storage portion 54 to the compression chamber 68, the oil supply path 100 has a suction port 101a, the lubricating oil sucked from the suction port 101a can be supplied to the compression chamber 68 by immersing the suction port 101a in the lubricating oil stored in the oil storage portion 54, the compression chamber 68 is sealed by the lubricating oil, and the prescribed state is a state in which the suction port 101a of the oil supply path 100 is not immersed in the lubricating oil stored in the oil storage portion 54.

[0022] The inventors of the present application conducted intensive research and found the following phenomenon: "When the suction port 101a of the oil supply path 100 is no longer immersed in the lubricating oil stored in the oil storage portion 54 in the compressor 50, the sealing of the compression chamber 68 by the lubricating oil fails, and as a result, a specific frequency component included in a physical quantity related to the state of the compressor 50 changes sharply".

[0023] In the fifth aspect, processing for coping with a 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 stored in the oil storage portion 54" can be appropriately performed.

[0024] The sixth aspect of the present disclosure is a control device in which, on the basis of the control device of any one of the first to third aspects, the prescribed state is a liquid compression state in which a liquid-like working fluid is sucked into the compression mechanism 65 and compressed in the compression mechanism 65.

[0025] The inventors of the present application conducted intensive research and found the following phenomenon: "When a liquid-like 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 related to the state of the compressor 50 changes sharply".

[0026] In the sixth aspect, processing for coping with a case where the state of the compressor 50 is "a liquid compression state in which a liquid-like working fluid is sucked into the compression mechanism 65 and compressed in the compression mechanism 65" can be appropriately performed.

[0027] The seventh aspect of the present disclosure is a control device, wherein the physical quantity is any of a rotational frequency of the motor 60, a voltage applied to the motor 60, a current flowing through the motor 60, a vibration of the compressor 50, a sound of the compressor 50, and a sound around the compressor 50, on the basis of the control device of any one of the first to sixth aspects.

[0028] The eighth aspect of the present disclosure is a control device, wherein the frequency of the specific frequency component is a frequency synchronized with a rotational frequency of the motor 60, on the basis of the control device of any one of the first to seventh aspects.

[0029] The ninth aspect of the present disclosure relates to a refrigeration system provided with a refrigerant circuit RR1 including a compressor 50 having a motor 60 and a compression mechanism 65, and the control device 30 of any one of the first to eighth aspects.

[0030] The tenth aspect of the present disclosure relates to a control method of controlling a system provided with a compressor 50 having a motor 60 and a compression mechanism 65, the control method including: a step of acquiring a physical quantity related to a state of the compressor 50; and a step of, in a case where a relationship between an index value indicating a magnitude of a specific frequency component included in the physical quantity acquired in the acquiring step and a predetermined threshold value becomes a prescribed relationship, at least one of a step of outputting information indicating that the state of the compressor 50 is a prescribed state and a step of changing an operation condition of the system.

[0031] In the eleventh aspect, by performing the step of coping in a case where a relationship between an index value indicating a magnitude of a specific frequency component included in a physical quantity related to a state of the compressor 50 and a predetermined threshold value becomes a prescribed relationship, it is possible to appropriately perform processing for coping with a case where the state of the compressor 50 is a prescribed state (a state in which the specific frequency component sharply changes).

[0032] The eleventh aspect of the present disclosure is a control program that causes a computer to execute the control method of the tenth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a block diagram illustrating the structure of a drive system of an embodiment.

[0034] Figure 2 is a longitudinal sectional view illustrating the internal structure of a compressor.

[0035] Figure 3 is a graph illustrating the relationship between the amount of oil and the specific frequency component.

[0036] Figure 4 is a graph that illustrates a change over time of a specific frequency component before and after the occurrence of an oil amount abnormality.

[0037] Figure 5 is a graph that illustrates a change over time of a specific frequency component when the oil amount is normal and a change over time of a specific frequency component when failure of the sealability of the lubricating oil to the compression chamber occurs.

[0038] Figure 6 is a graph that illustrates a change over time of a specific frequency component when liquid compression occurs.

[0039] Figure 7 is a graph that illustrates a change over time of a specific frequency component when the engine is normally operated and a change over time of a specific frequency component when liquid compression occurs.

[0040] Figure 8 is a flowchart that illustrates the inference processing of the control unit.

[0041] Figure 9 is a graph for explaining the first inference processing.

[0042] Figure 10 is a graph for explaining the second inference processing.

[0043] Figure 11 is a graph for explaining the third inference processing.

[0044] Figure 12 is a graph that illustrates a first moving average value and a second moving average value.

[0045] Figure 13 is a graph for explaining the fourth inference processing.

[0046] Figure 14 is a piping system diagram that illustrates the structure of the refrigeration system.

[0047] Figure 15 is a graph for explaining the derivation of the amplitude value of the specific frequency component.

[0048] Figure 16 is a graph that illustrates the variation of the index value corresponding to the state of the compressor.

[0049] Figure 17 is a graph that illustrates a change over time of torque in a double-cylinder type compressor. DETAILED DESCRIPTION

[0050] Hereinafter, the embodiments will be described in detail with reference to the drawings. In addition, the same reference numerals are assigned to the same or equivalent portions, and the description thereof will be omitted.

[0051] (Embodiment)

[0052] Figure 1 The configuration of the drive system 10 of the example embodiment is described. The drive system 10 drives the motor 60 using electric power supplied from the power supply 5. The motor 60 is mounted on the compressor 50. The compressor 50 has, in addition to the motor 60, a compression mechanism 65. The compression mechanism 65 is driven by the motor 60, sucks in working fluid, compresses it, and ejects the compressed working fluid. The working fluid is, for example, a refrigerant.

[0053] In this example, the power supply 5 is a three-phase alternating-current power supply, and the motor 60 is a three-phase alternating-current motor. The motor 60 is, for example, an IPM motor (Interior Permanent Magnet Motor). The drive system 10 is mounted on the device 1. The device 1 is, for example, an outdoor unit of an air conditioner. The drive system 10 has the motor drive device 20 and the control device 30.

[0054] 〔Motor Drive Device〕

[0055] The motor drive device 20 drives the motor 60. Specifically, the motor drive device 20 converts electric power supplied from the power supply 5 into output alternating-current electric power (three-phase alternating-current electric power in this example) having a prescribed frequency and voltage, and supplies the output alternating-current electric power to the motor 60. In this example, the motor drive device 20 has a converter 21, a direct-current portion 22, and an inverter 23.

[0056] The converter 21 rectifies electric power supplied from the power supply 5. In this example, the converter 21 full-wave-rectifies alternating-current electric power supplied from the power supply 5. The converter 21 is, for example, configured by a diode bridge circuit in which a plurality of rectifier diodes are connected in a bridge shape.

[0057] The direct-current portion 22 generates direct-current electric power corresponding to the electric power supplied from the power supply 5. In this example, the direct-current portion 22 has a capacitor, and smoothes the output of the converter 21.

[0058] The inverter 23 has a plurality of switching elements, and converts the output of the direct-current portion 22 into output alternating-current electric power (three-phase alternating-current electric power) having a prescribed frequency and voltage through switching operations of the plurality of switching elements. The inverter 23 is an example of a conversion portion that converts direct-current electric power generated by the direct-current portion 22 into alternating-current electric power through switching operations.

[0059] In this example, the inverter 23 has six switching elements connected in a bridge configuration and six freewheeling diodes connected in reverse parallel with the six switching elements, respectively. In detail, the inverter 23 has three switching arms each composed of two switching elements connected in series. The midpoints of the three switching arms (specifically, the connection points of the switching elements on the upper arm side and the switching elements on the lower arm side) are connected to the three windings of the motor 60 (the windings of the U-phase, the V-phase, and the W-phase), respectively.

[0060] 〔Various Sensors〕

[0061] Various sensors such as a phase current detection section 41, an electrical angular frequency detection section 42, and the like are provided in the motor drive device 20. Various information detected by the various sensors is sent to the control device 30. Specifically, the detection signals of the various sensors are sent to a control section 31 described later. The various sensors are an example of detection sections that detect information for obtaining a physical quantity related to the state of the compressor 50. Also, various sensors for acquiring various physical quantities are provided in the drive system 10 and a refrigeration system RR described later.

[0062] The phase current detection section 41 detects the phase currents (U-phase current iu, V-phase current iv, and W-phase current iw) of the three phases that flow through the three windings (omitted from illustration) of the motor 60, respectively. For example, the phase current detection section 41 can detect all of the phase currents iu, iv, and iw of the three phases, can detect two of the phase currents iu, iv, and iw of the three phases, and can derive the remaining one of the phase currents based on the two detected phase currents. Also, the phase current detection section 41 can derive the phase currents iu, iv, and iw of the three phases from the direct current detected by a shunt resistor (omitted from illustration) provided in the direct current section 22 and the switching pattern.

[0063] The electrical angular frequency detection section 42 detects the electrical angular frequency ω of the motor 60. Note that the electrical angular frequency detection section 42 is not necessarily provided, and the electrical angular frequency ω of the motor 60 can be calculated by another method or inferred in a sensorless manner.

[0064] 〔Control Device (State Inference Device)〕

[0065] The control device 30 infers the state of the compressor 50. The control device 30 is an example of a state inference device that infers the state of the compressor 50. The processing in the control device 30 (processing related to the inference of the state of the compressor 50) is an example of a state inference method that infers the state of the compressor 50. Also, the processing in the control device 30 (processing related to the control of the system that includes the compressor 50) is an example of a control method that controls the system that includes the compressor 50.

[0066] In this example, the control device 30 infers the state of the compressor 50, and performs processing corresponding to the inferred state of the compressor 50. Also, the control device 30 controls the motor 60. Specifically, the control device 30 controls the motor 60 by controlling the motor drive device 20.

[0067] 〔Control section〕

[0068] The control device 30 is provided with a control section 31. The control section 31 performs various kinds of processing. Specifically, the control section 31 acquires information and data from each section of the apparatus 1, and performs various kinds of processing based on these information and data. The processing of the control section 31 will be described later in detail.

[0069] For example, the control section 31 includes a processor, and a memory electrically connected to the processor and storing a program for causing the processor to act. By executing the program by the processor, various functions of the control section 31 are realized. Note that the control section 31 is an example of a computer, and the above-mentioned program is an example of a state inference program, and also an example of a control program.

[0070] 〔Control section's processing〕

[0071] In this example, the control section 31 performs inference processing, control processing, and coping processing.

[0072] 〔Inference processing〕

[0073] In the inference processing, the control section 31 infers the state of the compressor 50. Specifically, the control section 31 infers the state of the compressor 50 based on the magnitude of the change over time of the specific frequency component included in the physical quantity related to the state of the compressor 50. For example, the magnitude of the change over time of the specific frequency component is represented by the amount of change per unit time of the specific frequency component. In the inference processing, it is inferred whether the state of the compressor 50 is "a state in which the specific frequency component changes sharply (specifically, sharply rises or sharply falls)". The inference processing will be described later in detail.

[0074] 〔Control processing〕

[0075] In the control processing, the control section 31 controls the motor drive device 20 to control the motor 60. Specifically, the control section 31 inputs a target command value such as a command value of the electrical angular frequency ω of the motor 60, a detection signal of various sensors provided to the motor drive device 20, and the like. Further, the control section 31 controls the switching operation of the inverter 23 based on the target command value, the detection signal of the various sensors, and the like, thereby controlling the alternating-current power supplied from the inverter 23 to the motor 60.

[0076] 〔Coping processing〕

[0077] In this example, when it is inferred in the inference processing that the state of the compressor 50 is the "state in which the specific frequency component sharply changes", the control section 31 performs the coping processing. The coping processing is processing for coping with the "state in which the specific frequency component sharply changes" of the compressor 50, and includes at least one of output processing of outputting first information indicating that the state of the compressor 50 is the "state in which the specific frequency component sharply changes", and change processing of changing the operating condition of the motor 60.

[0078] As examples of the output processing, the following first output processing, second output processing, third output processing, combinations thereof, and the like can be given. The first output processing is processing of causing a display device (omitted from the drawing) provided to a remote controller or the like to display the first information by outputting the first information to the display device. The second output processing is processing of causing a control section (omitted from the drawing) that controls the operation of the control device 1 to perform processing for coping with the operation of the control device 1 in the abnormal state by outputting the first information to the control section. The third output processing is processing of uploading the first information to a data accumulation section (omitted from the drawing) on the cloud.

[0079] As examples of the change processing, the following first change processing, second change processing, third change processing, combinations thereof, and the like can be given. The first change processing is processing of stopping the motor 60. The second change processing is processing of accelerating the motor 60. The third change processing is processing of decelerating the motor 60.

[0080] 〔Details of the compressor〕

[0081] As shown in Figure 2 , the compressor 50 is a hermetic scroll compressor. The compressor 50 includes a casing 51, a motor 60, a compression mechanism 65, a first support section 80, and a second support section 85. The motor 60, the compression mechanism 65, the first support section 80, and the second support section 85 are housed in the casing 51.

[0082] 〈Housing〉

[0083] The casing 51 is a hermetic container that is cylindrical and has both ends closed, and the axial direction thereof is the up-down direction. In the internal space of the casing 51, the compression mechanism 65, the first support section 80, the motor 60, and the second support section 85 are arranged in this order from the top to the bottom. Also, an oil storage section 54 that stores lubricating oil (refrigerant oil) is formed in the bottom of the casing 51.

[0084] The casing 51 has a suction pipe 52 and a discharge pipe 53. The suction pipe 52 penetrates the top of the casing 51 and is connected to the compression mechanism 65 to guide the low-pressure working fluid from outside the compressor 50 to the compression mechanism 65. The discharge pipe 53 penetrates the trunk portion of the casing 51 and opens toward the inside space of the casing 51 (the space below the second support portion 85). The discharge pipe 53 guides the high-pressure working fluid guided to the space below the second support portion 85 of the casing 51 after being discharged from the compression chamber 68 to the outside of the compressor 50. According to such a structure, the high-pressure working fluid discharged from the compression chamber 68 acts on the space below the second support portion 85 of the casing 51 (including the oil reservoir portion 54) by the pressure thereof.

[0085] <Engine>

[0086] The motor 60 has a stator 61 and a rotor 62. The stator 61 is fixed to the trunk portion of the casing 51. The rotor 62 is disposed inside the stator 61. Also, the drive shaft 70 is inserted through the rotor 62.

[0087] <First support portion>

[0088] The first support portion 80 has a main portion 81 and a first bearing portion 82. The main portion 81 is formed in a thick-walled circular plate shape and is fixed to the casing 51. A crank chamber 81a is formed in the central portion of the main portion 81. The crank chamber 81a is a cylindrical recessed portion that opens on the front surface (the upper surface in the Figure 2 Figure 2

[0089] <Second support portion>

[0090] The second support portion 85 has a second bearing portion 86 and three leg portions 87. The second bearing portion 86 is formed in a thick-walled cylindrical shape. A second bearing 92 described later is embedded in the second bearing portion 86. The leg portions 87 extend radially from the second bearing portion 86. The leg portions 87 of the second support portion 85 are fixed to the trunk portion of the casing 51 at the distal ends thereof.

[0091] <Compression mechanism>

[0092] The compression mechanism 65 is a scroll-type fluid machine. The compression mechanism 65 has a stationary scroll 66 and an orbiting scroll 67. The scrolls of the stationary scroll 66 and the orbiting scroll 67 are engaged with each other to form a compression chamber 68.

[0093] ​​The stationary scroll 66 has a stationary-side end plate portion 66a, a stationary-side scroll wrap 66b, and an outer peripheral wall portion 66c. The stationary-side end plate portion 66a is a flat plate-shaped portion having a large thickness at the upper portion of the stationary scroll 66. The stationary-side scroll wrap 66b is formed in a scroll wall shape and projects from the front surface (lower surface in Figure 2 Figure 2 The outer peripheral wall portion 66c is formed to surround the outer peripheral side of the stationary-side scroll wrap 66b and projects from the front surface (lower surface in Figure 2 The stationary-side end plate portion 66a is fixed to the first support portion 80 that is fixed to the housing 51. The suction port sp is formed in the outer peripheral wall portion 66c, and the suction pipe 52 is inserted into the suction port sp. The discharge port dp is formed in the stationary-side end plate portion 66a.

[0094] Figure 2 The movable scroll 67 has a movable-side end plate portion 67a, a movable-side scroll wrap 67b, and a flange portion 67c. The movable-side end plate portion 67a is formed in a substantially circular flat plate shape. The movable-side scroll wrap 67b is formed in a scroll wall shape and projects from the front surface (upper surface in Figure 2 Figure 2 The flange portion 67c is formed in a cylindrical shape that projects from the back surface (lower surface in Figure 2 The flange portion 67c is formed in a cylindrical shape that projects from the back surface (lower surface in

[0095] The drive shaft 70 has a main shaft portion 71 and an eccentric shaft portion 72. The main shaft portion 71 has a main shaft neck portion 71a, a sub shaft neck portion 71b, and an intermediate shaft portion 71c. The drive shaft 70 is disposed in a posture in which the eccentric shaft portion 72 is located above the main shaft portion 71.

[0096] The main shaft neck portion 71a, the intermediate shaft portion 71c, and the sub shaft neck portion 71b are sequentially disposed in the main shaft portion 71 from one end toward the other end thereof. The main shaft neck portion 71a, the intermediate shaft portion 71c, and the sub shaft neck portion 71b are respectively formed in a cylindrical shape and are coaxially disposed. The diameter of the main shaft neck portion 71a is larger than the diameter of the intermediate shaft portion 71c, and the diameter of the sub shaft neck portion 71b is smaller than the diameter of the intermediate shaft portion 71c. Furthermore, the main shaft neck portion 71a is located at a position higher than the intermediate shaft portion 71c, and the sub shaft neck portion 71b is located at a position lower than the intermediate shaft portion 71c.

[0097] The main shaft neck portion 71a is inserted into the inside of the first bearing 91 that is embedded in the first bearing portion 82 of the first support portion 80 and is supported by the first bearing 91. The sub shaft neck portion 71b is inserted into the inside of the second bearing 92 that is embedded in the second bearing portion 86 of the second support portion 85 and is supported by the second bearing 92. The intermediate shaft portion 71c is inserted into the inside of the rotor 62 of the motor 60 and is fixed to the rotor 62.

[0098] The main shaft neck portion 71a is inserted into the inside of the first bearing 91 that is embedded in the first bearing portion 82 of the first support portion 80 and is supported by the first bearing 91. The sub shaft neck portion 71b is inserted into the inside of the second bearing 92 that is embedded in the second bearing portion 86 of the second support portion 85 and is supported by the second bearing 92. The intermediate shaft portion 71c is inserted into the inside of the rotor 62 of the motor 60 and is fixed to the rotor 62.

[0099] The eccentric shaft portion 72 is formed as a shorter shaft and protrudes from the end face of the main shaft journal 71a. The eccentric shaft portion 72 is located on the upper side of the main shaft portion 71. The axis of the eccentric shaft portion 72 is substantially parallel to the axis of the main shaft portion 71 and is eccentric relative to the axis of the main shaft portion 71. The eccentric shaft portion 72 is inserted through and into the inner side of the third bearing 93 embedded in the flange portion 67c of the moving scroll disk 67, and is supported by the third bearing 93.

[0100] (Bearings)

[0101] The first bearing 91, the second bearing 92, and the third bearing 93 are all cylindrical in shape and are sliding bearings that support the drive shaft 70.

[0102] The first bearing 91 is embedded inside the first bearing portion 82 of the first support portion 80. The main shaft journal 71a of the drive shaft 70 is inserted inside the first bearing 91, and the first bearing 91 supports the main shaft journal 71a of the drive shaft 70.

[0103] The second bearing 92 is embedded inside the second bearing portion 86 of the second support portion 85. The secondary journal 71b of the drive shaft 70 is inserted inside the second bearing 92, and the second bearing 92 supports the secondary journal 71b of the drive shaft 70.

[0104] The third bearing 93 is embedded inside the flange portion 67c of the moving scroll disk 67. The eccentric shaft portion 72 of the drive shaft 70 is inserted inside the third bearing 93, and the third bearing 93 supports the eccentric shaft portion 72 of the drive shaft 70.

[0105] (Fuel supply path)

[0106] An oil supply path 100 is provided in the compressor 50. The oil supply path 100 is a path (passage) for supplying lubricating oil (refrigeration oil) accumulated in the oil storage section 54 formed at the bottom of the housing 51 to the sliding parts. The oil supply path 100 has a main oil supply path 101 and a secondary oil supply path 102.

[0107] The main oil supply path 101 is formed within the drive shaft 70. The main oil supply path 101 extends axially from one end of the drive shaft 70 to the other end (in... Figure 2 The main oil supply path 101 extends axially from the bottom to the top, and branch paths extend from the main path toward the sliding portion of the drive shaft 70 with the first bearing 91, the sliding portion of the drive shaft 70 with the second bearing 92, and the sliding portion of the drive shaft 70 with the third bearing 93. The main oil supply path 101 guides the lubricating oil (refrigeration oil) accumulated in the oil storage section 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).

[0108] The sub-oil supply path 102 is formed so as to extend across the first support portion 80 and the fixed scroll 66, and guide the lubricating oil accumulated in the crank chamber 81a to the compression chamber 68 (specifically, the gap between the fixed scroll 66 and the orbiting scroll 67) of the compression mechanism 65. The sub-oil supply path 102 is formed so as to open at one end in the crank chamber 81a and at the other end in the gap between the outer peripheral wall portion 66c of the fixed scroll 66 and the dynamic side end plate portion 67a of the orbiting scroll 67. In the crank chamber 81a, the lubricating oil that has been guided from the oil storage portion 54 to the sliding portion between the drive shaft 70 and the third bearing 93 via the main-oil supply path 101, and has flowed out from the sliding portion after lubricating the sliding portion, is accumulated. The sub-oil supply path 102 guides the lubricating oil that has been lubricated the sliding portion between the drive shaft 70 and the third bearing 93, from the crank chamber 81a to the compression mechanism 65. The lubricating oil that has been guided to the compression mechanism 65 seals the compression chamber 68 (specifically, the gap between the fixed scroll 66 and the orbiting scroll 67).

[0109] According to such a configuration, the lubricating oil in the oil storage portion 54, on which the pressure (high-pressure pressure) of the working fluid ejected from the compression mechanism 65 acts, flows into the main-oil supply path 101 via the suction port 101a of the main-oil supply path 101, flows in the main-oil supply path 101, and is supplied to the sliding portion 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 that has been supplied to the sliding portion between the drive shaft 70 and the third bearing 93 lubricates the sliding portion between the drive shaft 70 and the third bearing 93, and is accumulated in the crank chamber 81a. The lubricating oil accumulated in the crank chamber 81a is supplied to the compression chamber 68 (specifically, the gap between the fixed scroll 66 and the orbiting scroll 67) of the compression mechanism 65 via the sub-oil supply path 102, and seals the compression chamber 68.

[0110] 〔Insight obtained by the present inventors〕

[0111] The present inventors have conducted intensive research, and as a result, have found that in the state of the compressor 50 having the motor 60 and the compression mechanism 65, there is a state in which a specific frequency component included in a physical quantity related to the state of the compressor 50 changes sharply.

[0112] Specifically, the inventors of the present application found the phenomenon that "when the sealability of the compression chamber 68 by the lubricating oil is lost in the compressor 50, a specific frequency component included in a physical quantity related to the state of the compressor 50 changes drastically". In particular, the inventors of the present application found the phenomenon that "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 in the compressor 50, the sealability of the compression chamber 68 by the lubricating oil is lost, as a result of which a specific frequency component included in a physical quantity related to the state of the compressor 50 changes drastically".

[0113] Further, the inventors of the present application found that the above-mentioned state (the state of the compressor 50 in which the specific frequency component changes drastically) can be inferred based on the magnitude of the change over time of the specific frequency component included in the physical quantity.

[0114] Further, the inventors of the present application found that the above-mentioned state (the state of the compressor 50 in which the specific frequency component changes drastically) can be inferred based on the magnitude of the change over time of the specific frequency component included in the physical quantity.

[0115] Hereinafter, the insight obtained by the inventors of the present application will be described in detail. Note that, hereinafter, a case in which the physical quantity related to the state of the compressor 50 is "the current vector amplitude Ia" and the specific frequency component included in the physical quantity is "a frequency component having a frequency one time the mechanical angular frequency of the motor 60 (hereinafter, referred to as "the first component")" will be described as an example. The "current vector amplitude Ia" is an example of a physical quantity related to the torque of the compressor 50, and is also an example of a physical quantity related to the voltage or current of the motor 60. Note that the mechanical angular frequency of the motor 60 corresponds to the rotational frequency of the motor 60.

[0116] 〔Loss of the sealability of the compression chamber 68 by the lubricating oil〕

[0117] First, reference will be made to Figure 2 The loss of the sealability of the compression chamber 68 will be described. In the compressor 50, if 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 sealability of the compression chamber 68 by the lubricating oil is lost, and the amplitude of the torque pulsation of the compressor 50 drastically decreases. Specifically, the magnitude of the first component of the rotational frequency of the motor 60 in the torque drastically decreases. Therefore, when the sealability of the compression chamber 68 by the lubricating oil is lost, the first component of the rotational frequency of the motor 60 in the current vector amplitude Ia drastically decreases.

[0118] Next, reference will be made to Figure 3 and Figure 4The changes in specific frequency components corresponding to changes in the amount of oil accumulated in the oil storage section 54 will be explained. In the following explanation, "oil amount" refers to the amount of oil accumulated in the oil storage section 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 storage section 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 storage section 54.

[0119] like Figure 3 As shown, as the oil quantity gradually decreases, the amplitude value of a specific frequency component gradually decreases. It should be noted that the oil quantity varies depending on the operating conditions of the compressor 50. Figure 4 As shown, when the oil level changes from normal to abnormal at time t1, the amplitude of a specific frequency component drops sharply.

[0120] like Figure 3 and Figure 4 As shown, the amplitude of a specific frequency component when the fuel level is abnormal is smaller than that of a different frequency component when the fuel level is abnormal. Therefore, to distinguish between normal and abnormal fuel levels, it is considered to compare the magnitude (amplitude) of the specific frequency component with a threshold. However, in setting the threshold for comparison with the magnitude of the specific frequency component, it is necessary to consider the errors contained in the specific frequency component (sensor errors, errors caused by pressure and temperature effects, etc.), so it is sometimes difficult to set the above threshold appropriately.

[0121] For example, if the central value of a specific frequency component when the oil level is normal (e.g., the central value of the assumed amplitude of change) is "1.37A" and the central value of a specific frequency component when the oil level is abnormal is "0.75A", the threshold used to distinguish between normal and abnormal oil levels is preferably set between "0.75A" and "1.37A". However, the value of the specific frequency component when the oil level is normal has an amplitude due to errors (such as sensor errors, errors caused by pressure and temperature), and the influence of oil level, with a minimum value of "0.85A". Similarly, the value of the specific frequency component when the oil level is abnormal also has an amplitude due to errors, with a maximum value of "1.23A". Therefore, it is not possible to set the above threshold appropriately. It should be noted that the value of the specific frequency component changes due to errors and the influence of oil level because the waveform of the physical quantity (the physical quantity related to the state of the compressor 50) changes due to errors and the influence of oil level.

[0122] It should be noted that, as Figure 5 As shown, the time variation of specific frequency components when the sealing performance of the lubricating oil to the compression chamber 68 fails (in... Figure 5 In the example, the time variation within the TA period is much greater than the time variation of a specific frequency component that accompanies the increase or decrease in oil volume when the oil volume is normal (in Figure 5In the example, TB changes over time during the period. Figure 5 The vertical axis represents the percentage (relative 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 the period TB as the reference (100%). For example, the change of a specific frequency component over time when the sealing of the lubricating oil to the compression chamber 68 fails is "a decrease of 40% over 30 seconds (1.333% / second)," while the change of a specific frequency component over time caused by the increase or decrease in oil quantity when the oil quantity is normal is "a decrease of 11% over 1800 seconds (0.006% / second)."

[0123] Therefore, based on the magnitude of the change of a specific frequency component over time, it is possible to identify a sharp change (specifically a sharp decrease) in a specific frequency component when the sealing of the compression chamber 68 by the lubricating oil fails. For example, by comparing the value representing the magnitude of the change of a specific frequency component over time with a threshold, it is possible to infer whether the state of the compressor 50 is "the state of lubricating oil sealing failure of the compression chamber 68".

[0124] Furthermore, in order to set a threshold for comparing the magnitude of a specific frequency component with the time-varying magnitude, errors contained in the specific frequency component (such as sensor errors, errors caused by pressure and temperature effects, etc.) can be disregarded. Therefore, compared to setting a threshold for comparing the magnitude of a specific frequency component, the threshold can be set appropriately.

[0125] Specifically, the time-varying variation of the specific frequency component caused by changes in pressure and temperature is much smaller than the time-varying variation of the specific frequency component when the sealing of the lubricating oil to the compression chamber 68 fails. Furthermore, the time-varying variation of the specific frequency component caused by changes in pressure and temperature is much smaller than the difference between the time-varying variation of the specific frequency component when the sealing of the lubricating oil to the compression chamber 68 fails and the time-varying variation of the specific frequency component caused by increases or decreases in oil quantity when the oil quantity is normal.

[0126] Furthermore, to reduce errors contained in specific frequency components, it is considered to prepare thresholds separately for each solid state of each sensor or for each pressure and temperature. However, in this method, the state inference algorithm becomes complex, increasing the computational load and thus raising the cost of processors and other computing units. On the other hand, in the method of the implementation (state inference based on the magnitude of the time-varying change of a specific frequency component), a single threshold can be set only for the magnitude of the time-varying change of the specific frequency component, thus suppressing the increase in computational load and allowing existing processors to be used directly.

[0127] Furthermore, in order to understand the influence of oil quantity on specific frequency components, it is considered to install a separate sensor to detect oil quantity. However, in this method, the cost increases due to the installation of the sensor. On the other hand, in the method of the embodiment (state inference based on the magnitude of the change of specific frequency components over time), it is not necessary to install a separate sensor to detect oil quantity, thus avoiding the increase in cost caused by the installation of the sensor.

[0128] Furthermore, the method described in this implementation (state inference based on the magnitude of the time-varying changes of a specific frequency component) can capture changes in the current waveform when an anomaly occurs by focusing on the frequency component. By monitoring in this way, focusing on the frequency component, anomalies can be detected with higher accuracy compared to monitoring the effective value or average value.

[0129] [Liquid Compression]

[0130] Next, refer to Figure 6 The compression of liquid is explained below. In compressor 50, when a liquid working fluid is drawn into compression mechanism 65 and compressed therein, the amplitude of the torque pulsation in compressor 50 increases sharply. Specifically, the magnitude of the primary component of the rotational frequency of motor 60 in the torque increases sharply. Therefore, when liquid compression occurs, the primary component of the rotational frequency of motor 60 in the current vector amplitude Ia increases sharply.

[0131] like Figure 6 As shown, when liquid compression occurs at time t1, the amplitude value of a specific frequency component increases sharply. Then, when the liquid working fluid disappears from the compression mechanism 65, the amplitude value of the specific frequency component returns to normal.

[0132] And, as Figure 6 As shown, the amplitude of a specific frequency component during liquid compression is larger than that during normal operation. Therefore, to distinguish between normal operation and liquid compression, it is considered to compare the magnitude (amplitude) of the specific frequency component with a threshold. However, in setting the threshold for comparison with the magnitude of the specific frequency component, it is necessary to consider the errors contained in the specific frequency component (sensor errors, errors caused by pressure and temperature effects, etc.), so it is sometimes difficult to set the above threshold appropriately.

[0133] For example, in a case where the central value of the specific frequency component at the time of normal operation (for example, the central value of the assumed variation range) is "1.37 A" and the central value of the specific frequency component at the time of liquid compression is "1.96 A", the threshold value for discriminating between the normal operation and the liquid compression is preferably set between "1.37 A" and "1.96 A". However, the value of the specific frequency component at the time of the normal operation has a range with a maximum value of "1.89 A" due to errors (errors of the sensor, errors caused by influences of pressure and temperature, and the like), influences of the oil amount. Similarly, the value of the specific frequency component at the time of the liquid compression also has a range with a minimum value of "1.44 A" due to errors, influences of the oil amount. Therefore, the above-mentioned threshold value cannot be properly set.

[0134] In addition, as shown in FIG. 6, the variation over time of the specific frequency component at the time of the liquid compression (the variation over time within the period TC in the example of FIG. 6) is much larger than the variation over time of the specific frequency component at the time of the normal operation (the variation over time within the period TD in the example of FIG. 6). Figure 7 Figure 7 In addition, as shown in FIG. 6, the variation over time of the specific frequency component at the time of the liquid compression (the variation over time within the period TC in the example of FIG. 6) is much larger than the variation over time of the specific frequency component at the time of the normal operation (the variation over time within the period TD in the example of FIG. 6). Figure 7 Figure 7 The vertical axis of FIG. 6 indicates a percentage of the amplitude value of the specific frequency component (the ratio with respect to the reference) based on the amplitude value of the specific frequency component at the beginning of the period TD (100%). For example, the variation over time of the specific frequency component at the time of the liquid compression is "a variation of 43% increase (2.15% / sec) in 20 seconds", and the variation over time of the specific frequency component at the time of the normal operation is "a variation of 11% increase or decrease (0.006% / sec) in 1800 seconds".

[0135] Therefore, based on the magnitude of the variation over time of the specific frequency component, it is possible to recognize the sharp change (specifically, the sharp increase) of the specific frequency component at the time of the liquid compression. For example, by comparing the value indicating the magnitude of the variation over time of the specific frequency component with a threshold value, it is possible to infer whether the state of the compressor 50 is the "liquid compression state".

[0136] Further, in order to set the threshold value to be compared with the magnitude of the variation over time of the specific frequency component, it is also possible not to take into account the errors (errors of the sensor, errors caused by influences of pressure and temperature, and the like) included in the specific frequency component. Therefore, compared to the case where the threshold value is set to be compared with the magnitude of the specific frequency component, it is possible to properly set the threshold value.

[0137] ​​Specifically, the time variation of the specific frequency component accompanying the changes in the pressure and the temperature is much smaller than the time variation of the specific frequency component when the liquid compression occurs. Also, the time variation of the specific frequency component accompanying the changes in the pressure and the temperature is much smaller than the difference between the time variation of the specific frequency component when the liquid compression occurs and the time variation of the specific frequency component when the air conditioner is normally operated.

[0138] (Details of the inference processing)

[0139] In the inference processing, the control portion 31 infers whether or not the state of the compressor 50 is the "state in which the specific frequency component sharply varies" on the basis of the magnitude of the time variation of the specific frequency component included in the physical quantity related to the state of the compressor 50. For example, the "state in which the specific frequency component sharply varies" can be said to be a state in which the amount of variation of the specific frequency component per unit time exceeds a predetermined reference amount.

[0140] Note that in this example, the physical quantity is a physical quantity related to the torque of the compressor 50. The physical quantity is a physical quantity related to the voltage or the current of the motor 60. The control portion 31 performs the inference processing on the basis of a signal indicating the physical quantity. Specific examples of the signal indicating the physical quantity will be described later in detail.

[0141] Also, in this example, the frequency of the specific frequency component is a frequency synchronized with the mechanical angular frequency of the motor 60. In other words, the frequency of the specific frequency component is a frequency corresponding to the mechanical angular frequency of the motor 60. Specifically, the frequency of the specific frequency component is an integral 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.

[0142] Also, in this example, in the inference processing, the control portion 31 infers whether or not the state of the compressor 50 is the "state in which the sealability of the compression chamber by the lubricating oil is lost". Alternatively, the control portion 31 infers whether or not the state of the compressor 50 is the "liquid compression state in which the working fluid in a liquid state is sucked into the compression mechanism 65 and compressed in the compression mechanism 65".

[0143] In other words, in this example, the "state in which the specific frequency component sharply varies" of the compressor 50 inferred by the control portion 31 is the "state in which the sealability of the compression chamber by the lubricating oil is lost" or the "liquid compression state in which the working fluid in a liquid state is sucked into the compression mechanism 65 and compressed in the compression mechanism 65".

[0144] Note that in this example, the "state in which the sealability of the compression chamber by the lubricating oil is lost" is specifically 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, and the sealability of the compression chamber by the lubricating oil is lost". The control unit 31 can also infer whether the state of the compressor 50 is a "state in which the suction port 101a of the oil supply path 100 is not immersed in the lubricating oil accumulated in the oil reservoir 54".

[0145] 〔Flow of inference processing〕

[0146] Next, the flow of the inference processing will be described with reference to Figure 8 The flow of the inference processing will be described. The control unit 31 repeatedly performs the following processing.

[0147] 〈Step S1: acquisition step〉

[0148] First, the control unit 31 acquires a physical quantity (for example, the current vector amplitude Ia) related to the state of the compressor 50. In this example, the control unit 31 acquires the physical quantity based on information for acquiring a physical quantity related to the state of the compressor 50 (information obtained by various sensors) at every predetermined derivation time. By repeatedly performing such processing, the physical quantity is obtained at every derivation time.

[0149] Note that the sensor for acquiring "information for acquiring a physical quantity related to the state of the compressor 50" in the inference processing can be used as a sensor (for example, a current sensor or the like) used in the control processing, or can be a sensor provided separately from the sensor used in the control processing.

[0150] 〈Step S2: inference step〉

[0151] Next, the control unit 31 infers the state of the compressor 50 based on the magnitude of the change over time of a specific frequency component (for example, the first component) included in the physical quantity obtained in step S1. In this example, the control unit 31 derives a value (hereinafter referred to as an "index value") indicating the magnitude of the change over time of the specific frequency component included in the physical quantity based on the physical quantity obtained in step S1 at every predetermined inference time. Then, the control unit 31 compares the index value with a threshold value, and infers whether the state of the compressor 50 is a "state in which the specific frequency component changes sharply" based on the comparison result. By repeatedly performing such processing, the index value can be derived at every inference time, and the state of the compressor 50 can be inferred based on the index value. Specific examples of the inference processing will be described in detail later.

[0152] 〔Effects of the embodiment〕

[0153] As described above, in the drive system 10 of the embodiment, in the inference processing, the control portion 31 infers the state of the compressor 50 based on the magnitude of the time variation of the specific frequency component included in the physical quantity related to the state of the compressor 50.

[0154] According to the above-described structure, the state of the compressor 50 can be inferred to be the "state in which the specific frequency component sharply varies" based on the magnitude of the time variation of the specific frequency component.

[0155] Also, 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 by the lubricating oil. The control portion 31 infers in the inference processing whether the state of the compressor 50 is the "state in which the sealability of the compression chamber 68 by the lubricating oil is failed".

[0156] According to the above-described structure, the state of the compressor 50 can be inferred to be the "state in which the sealability of the compression chamber 68 by the lubricating oil is failed" based on the magnitude of the time variation of the specific frequency component.

[0157] Also, 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 storage portion 54 in which the lubricating oil is stored, and an oil supply path 100 for supplying the lubricating oil stored in the oil storage portion 54 to the compression chamber 68. The oil supply path 100 has a suction port 101a, and the lubricating oil sucked from the suction port 101a can be supplied to the compression chamber 68 by immersing the suction port 101a in the lubricating oil stored in the oil storage portion 54. The compression chamber 68 is sealed by the lubricating oil. The control portion 31 infers in the inference processing 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 stored in the oil storage portion 54".

[0158] According to the above-described structure, the state of the compressor 50 can be inferred to be the "state in which the suction port 101a of the oil supply path 100 is not immersed in the lubricating oil stored in the oil storage portion 54" based on the magnitude of the time variation of the specific frequency component.

[0159] Also, in the drive system 10 of the embodiment, the control portion 31 infers in the inference processing whether the state of the compressor 50 is the "liquid compression state in which the working fluid in a liquid state is sucked into the compression mechanism 65 and compressed in the compression mechanism 65".

[0160] According to the above-described structure, the state of the compressor 50 can be inferred to be the "liquid compression state in which the working fluid in a liquid state is sucked into the compression mechanism 65 and compressed in the compression mechanism 65" based on the magnitude of the time variation of the specific frequency component.

[0161] (Specific example of signal indicating physical quantity)

[0162] Next, specific examples of the "signal indicating a physical quantity related to the voltage or current of the motor 60" will be described. The signal is roughly classified into a direct current signal and an alternating current signal.

[0163] 〔Specific example of direct current signal〕

[0164] As examples of the direct current signal, there are "a signal related to the phase current iu, iv, iw of the motor 60", "a signal related to the phase voltage Vu, Vv, Vw of the motor 60", and "a signal related to the power of the motor 60".

[0165] As another example of the direct current signal, there are "a current iγ, iδ obtained by coordinate conversion of the phase current iu, iv, iw of the motor 60 using the phase ωi·t of the phase current iu, iv, iw of the motor 60", "a voltage Vγ, Vδ obtained by coordinate conversion of the phase voltage Vu, Vv, Vw of the motor 60 using the phase ωv·t of the phase voltage Vu, Vv, Vw of the motor 60", "a current iζ, iη obtained by coordinate conversion of the phase current iu, iv, iw of the motor 60 using the phase ωv·t of the phase voltage Vu, Vv, Vw of the motor 60", and "a voltage Vζ, Vη obtained by coordinate conversion of the phase voltage Vu, Vv, Vw of the motor 60 using the phase ωi·t of the phase current iu, iv, iw of the motor 60".

[0166] As still another example of the direct current signal, there are "a dq-axis flux λd, λq obtained by coordinate conversion of the armature flux linkage generated by the permanent magnet", and "a magnitude λ0 of the armature flux linkage vector obtained by synthesizing the armature flux linkage of the permanent magnet and the armature reaction".

[0167] Note that in the following description, "the phase current iu, iv, iw of the motor 60" is the phase current iu, iv, iw of the motor 60 detected by the phase current detection section 41. "The phase voltage Vu, Vv, Vw of the motor 60" is the phase voltage Vu, Vv, Vw of the motor 60 indicated by the voltage command value used inside the control section 31, or the phase voltage Vu, Vv, Vw of the motor 60 detected by a phase voltage detection section (not shown) provided to the motor drive device 20. "The electric angular frequency ω of the motor 60" is the electric angular frequency ω of the motor 60 detected by the electric angular frequency detection section 42.

[0168] 〔1. Specific example of signal related to phase current of motor〕

[0169] As a specific example of the signal related to the phase current iu, iv, iw of the motor 60, there are the current vector amplitude Ia, the square value Ia 2, phase current amplitude I, phase current effective value Irms, etc.

[0170] In addition, the current vector amplitude Ia and the square value Ia 2 is an example of a value corresponding to the sum of the square values of the respective phase currents iu, iv, iw of the three phases of the motor 60. The value corresponding to the sum of the square values of the respective phase currents iu, iv, iw of the three phases of the motor 60 is an example of a value proportional to an integer power of the magnitude of the phase currents iu, iv, iw of the motor 60.

[0171] (1) Current vector amplitude

[0172] The current vector amplitude Ia is derived on the basis of the phase currents iu, iv, iw of the motor 60. Also, the current vector amplitude Ia can be derived on the basis of the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 60 to a fixed coordinate system. The current vector amplitude Ia can also be derived on the basis of the M-axis current iM and the T-axis current iT obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to an angle of a direction based on primary magnetic flux. Also, the current vector amplitude Ia can be derived on the basis of the d-axis current id and the q-axis current iq obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to an angle of a direction based on a magnetic pole position. Specifically, the current vector amplitude Ia can be expressed as follows.

[0173] (Mathematical expression 1)

[0174]

[0175] (2) Square value of current vector amplitude

[0176] The square value Ia 2 of the current vector amplitude is derived on the basis of the phase currents iu, iv, iw of the motor 60. Also, the square value Ia 2 of the current vector amplitude can be derived on the basis of the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 60 to a fixed coordinate system. Also, the square value Ia 2 of the current vector amplitude can be derived on the basis of the M-axis current iM and the T-axis current iT obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to an angle of a direction based on primary magnetic flux. Also, the square value Ia 2The current vector amplitude Ia can also be derived based on the d-axis current id and the q-axis current iq, which are obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to the angle of the direction based on the magnetic pole position. Specifically, the square value Ia of the current vector amplitude can be expressed as follows. 2 The current vector amplitude Ia can also be derived based on the d-axis current id and the q-axis current iq, which are obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to the angle of the direction based on the magnetic pole position. Specifically, the square value Ia of the current vector amplitude can be expressed as follows.

[0177] (Mathematical Expression 2)

[0178]

[0179] (3) Phase current amplitude

[0180] The phase current amplitude I is derived based on one of the phase currents iu, iv, iw (for example, the U-phase current iu) of the motor 60 and the phase ωi of the phase current. In addition, the phase ωi of the phase current is derived based on the phase currents iu, iv, iw of the motor 60, for example. Specifically, the phase current amplitude I can be expressed as follows.

[0181] (Mathematical Expression 3)

[0182]

[0183] (4) Phase current effective value

[0184] The phase current effective value Irms is derived based on the phase current amplitude I. Specifically, the phase current effective value Irms can be expressed as follows.

[0185] (Mathematical Expression 4)

[0186]

[0187] (5) Others

[0188] In the above description, a case where the current vector amplitude Ia is derived based on the three-phase phase currents iu, iv, iw of the motor 60 is exemplified, but the current vector amplitude Ia can also be derived based on the two-phase phase currents among the three-phase phase currents iu, iv, iw of the motor 60. Also, the current vector amplitude Ia can be derived based on the direct-current of the inverter 23 detected by a direct-current detection unit (for example, a shunt resistor, not shown) provided in the motor drive device 20. The same applies to the square value Ia of the current vector amplitude 2 .

[0189] [2. Specific examples of signals related to phase voltage of motor]

[0190] As specific examples of signals related to the phase voltage Vu, Vv, Vw of the motor 60, the voltage vector amplitude Va, the square value Va 2, phase voltage amplitude V, phase voltage effective value Vrms, etc.

[0191] Note that the voltage vector amplitude Vaand the square value of the voltage vector amplitude Va 2 is an example of a value corresponding to the sum of the square values of the respective phase voltages Vu, Vv, and Vwof the three phases of the motor 60. The value corresponding to the sum of the square values of the respective phase voltages Vu, Vv, and Vwof the three phases of the motor 60 is an example of a value proportional to an integer power of the magnitudes of the phase voltages Vu, Vv, and Vwof the motor 60.

[0192] (1) Voltage vector amplitude

[0193] The voltage vector amplitude Va is derived based on the phase voltages Vu, Vv, and Vwof the motor 60. Also, the voltage vector amplitude Va can be derived based on the α-phase voltage Vα and the β-phase voltage Vβ obtained by converting the phase voltages Vu, Vv, and Vwof the motor 60 to a fixed coordinate system. Also, the voltage vector amplitude Va can be derived based on the M-axis voltage VM and the T-axis voltage VT obtained by coordinate-converting the phase voltages Vu, Vv, and Vwof the motor 60 according to an angle of a direction based on primary magnetic flux. Also, the voltage vector amplitude Va can be derived based on the d-axis voltage Vd and the q-axis voltage Vq obtained by coordinate-converting the phase voltages Vu, Vv, and Vwof the motor 60 according to an angle of a direction based on a magnetic pole position. Specifically, the voltage vector amplitude Va can be expressed as follows.

[0194] (Mathematical expression 5)

[0195]

[0196] (2) Square value of voltage vector amplitude

[0197] The square value of the voltage vector amplitude Va 2 is derived based on the phase voltages Vu, Vv, and Vwof the motor 60. Also, the square value of the voltage vector amplitude Va 2 can be derived based on the α-phase voltage Vα and the β-phase voltage Vβ obtained by converting the phase voltages Vu, Vv, and Vwof the motor 60 to a fixed coordinate system. Also, the square value of the voltage vector amplitude Va 2 can be derived based on the M-axis voltage VM and the T-axis voltage VT obtained by coordinate-converting the phase voltages Vu, Vv, and Vwof the motor 60 according to an angle of a direction based on primary magnetic flux. Also, the square value of the voltage vector amplitude Va 2The voltage vector amplitude Va can also be derived based on a d-axis voltage Vd and a q-axis voltage Vq, which are obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 60 according to the angle of the direction based on the magnetic pole position. Specifically, the square value of the voltage vector amplitude Va 2 The voltage vector amplitude Va can be expressed as follows.

[0198] (Mathematical expression 6)

[0199]

[0200] (3) Phase voltage amplitude

[0201] The phase voltage amplitude V is derived based on one of the phase voltages (for example, the U-phase voltage Vu) of the motor 60 and the phase ωv of the phase voltage. In addition, the phase ωv of the phase voltage is derived based on the phase voltages Vu, Vv, Vw of the motor 60, for example. Specifically, the phase voltage amplitude V can be expressed as follows.

[0202] (Mathematical expression 7)

[0203]

[0204] (4) Phase voltage effective value

[0205] The phase voltage effective value Vrms is derived based on the phase voltage amplitude V. Specifically, the phase voltage effective value Vrms can be expressed as follows.

[0206] (Mathematical expression 8)

[0207]

[0208] (5) Others

[0209] In the above description, the case where the voltage vector amplitude Va is derived based on the three-phase phase voltages Vu, Vv, Vw of the motor 60 is described as an example, but the voltage vector amplitude Va can also be derived based on the two-phase phase voltages among the three-phase phase voltages Vu, Vv, Vw of the motor 60. This also applies to the square value of the voltage vector amplitude Va 2 .

[0210] 〔3. Specific examples of signals related to the power of the motor〕

[0211] As examples of the signals related to the power of the motor 60, the instantaneous power p, the instantaneous reactive power q, the apparent power S, the active power P, the reactive power Q, and the like can be given.

[0212] (1) Instantaneous power

[0213] The instantaneous power p is derived based on the phase currents iu, iv, iw of the motor 60 and the phase voltages Vu, Vv, Vw of the motor 60. Also, the instantaneous power p can be derived based on the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 60 to a fixed coordinate system, and the α-phase voltage Vα and the β-phase voltage Vβ obtained by converting the phase voltages Vu, Vv, Vw of the motor 60 to the fixed coordinate system. Also, the instantaneous power p can be derived based on the M-axis current iM and the T-axis current iT obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to an angle of a direction based on primary magnetic flux, and the M-axis voltage VM and the T-axis voltage VT obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 60 according to the angle of the direction based on the primary magnetic flux. Also, the instantaneous power p can be derived based on the d-axis current id and the q-axis current iq obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to an angle of a direction based on a magnetic pole position, and the d-axis voltage Vd and the q-axis voltage Vq obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 60 according to the angle of the direction based on the magnetic pole position. Specifically, the instantaneous power p can be expressed as follows.

[0214] (Mathematical expression 9)

[0215]

[0216] (2) Instantaneous reactive power

[0217] The instantaneous reactive power q is derived based on the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 60 to the fixed coordinate system, and the α-phase voltage Vα and the β-phase voltage Vβ obtained by converting the phase voltages Vu, Vv, Vw of the motor 60 to the fixed coordinate system. Also, the instantaneous reactive power q can be derived based on the M-axis current iM and the T-axis current iT obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to the angle of the direction based on the primary magnetic flux, and the M-axis voltage VM and the T-axis voltage VT obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 60 according to the angle of the direction based on the primary magnetic flux. Also, the instantaneous reactive power q can be derived based on the d-axis current id and the q-axis current iq obtained by coordinate-converting the phase currents iu, iv, iw of the motor 60 according to the angle of the direction based on the magnetic pole position, and the d-axis voltage Vd and the q-axis voltage Vq obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 60 according to the angle of the direction based on the magnetic pole position. Specifically, the instantaneous reactive power q can be expressed as follows.

[0218] (Mathematical expression 10)

[0219]

[0220] (3) Apparent power

[0221] The apparent power S is derived based on the phase voltage effective value Vrms and the phase current effective value Irms. Specifically, the apparent power S can be expressed as follows.

[0222] (Mathematical expression 11)

[0223]

[0224] (4) Active power

[0225] The active power P is derived based on the phase voltage effective value Vrms, the phase current effective value Irms, and the phase difference φ1 of the phase voltage and the phase current, which is the phase difference of one phase voltage (for example, the U-phase voltage Vu) and one phase current (for example, the U-phase current iu) derived based on the phase of the phase current ωi and the phase of the phase voltage ωv. Specifically, the active power P can be expressed as follows.

[0226] (Mathematical expression 12)

[0227]

[0228] (5) Reactive power

[0229] The reactive power Q is derived based on the phase voltage effective value Vrms, the phase current effective value Irms, and the phase difference φ1 of the phase voltage and the phase current. The phase difference of the phase voltage and the phase current is, for example, the phase difference of the U-phase voltage Vu and the U-phase current iu, which is derived based on the phase of the phase current ωi and the phase of the phase voltage ωv. Specifically, the reactive power Q can be expressed as follows.

[0230] (Mathematical expression 13)

[0231]

[0232] 〔4. Current obtained by coordinate conversion of phase current using phase of phase current〕

[0233] The current iγ, iδ obtained by coordinate conversion of the phase currents iu, iv, iw of the motor 60 using the phase ωi•t of the phase currents iu, iv, iw of the motor 60 can be expressed as follows.

[0234] (Mathematical expression 14)

[0235]

[0236] 〔5. Voltage obtained by coordinate conversion of phase voltage using phase of phase voltage〕

[0237] The voltage Vγ, Vδ obtained by coordinate conversion of the phase voltages Vu, Vv, Vw of the motor 60 using the phase ωv•t of the phase voltages Vu, Vv, Vw of the motor 60 can be expressed as follows.

[0238] (Mathematical expression 15)

[0239]

[0240] 〔6. Current obtained by coordinate conversion of phase current using phase of phase voltage〕

[0241] The current iζ, iη obtained by coordinate conversion of the phase currents iu, iv, iw of the motor 60 using the phase ωv•t of the phase voltages Vu, Vv, Vw of the motor 60 can be expressed as follows.

[0242] (Mathematical expression 16)

[0243]

[0244] 〔7. Voltage obtained by coordinate conversion of phase voltage using phase of phase current〕

[0245] The voltages Vζ, Vη obtained by coordinate conversion of the phase voltages Vu, Vv, Vw of the motor 60 using the phase of the phase currents iu, iv, iw of the motor 60 ωi•t can be expressed as follows.

[0246] (Math. 17)

[0247]

[0248] 〔6. Size of dq-axis flux and armature cross-link flux vector〕

[0249] The size λ0 of the armature cross-link flux vector obtained by combining the armature cross-link flux of the permanent magnet and the armature reaction and the dq-axis fluxes λd, λq obtained by coordinate conversion of the armature cross-link flux generated by the permanent magnet can be expressed as follows. "Ld" in the following equation is the d-axis inductance, and "Lq" is the q-axis inductance.

[0250] (Math. 18)

[0251]

[0252] 〔7. Other examples of AC signal〕

[0253] Also, the DC signal can be a DC signal obtained by three-phase two-phase conversion of the phase currents, the phase voltages, the line currents, the line-to-line voltages of the motor 60 and further by rotational coordinate conversion. For example, the DC signal can be a d-axis current and a q-axis current obtained by rotational coordinate conversion of α-axis currents and β-axis currents obtained by three-phase two-phase conversion of the phase currents of the motor 60 using an angle based on the direction of the magnetic pole of the rotor of the motor 60. Also, the DC signal can be an M-axis current and a T-axis current obtained by rotational coordinate conversion of α-axis currents and β-axis currents using an angle based on the direction of the primary flux of the rotor of the motor 60.

[0254] Also, the DC signal can be a power input to the inverter 21 of the motor drive device 20, a power output from the inverter 21, a power output from the DC portion 22, a current flowing between the inverter 21 and the DC portion 22, a current flowing between the DC portion 22 and the inverter 23, and the like.

[0255] 〔Specific examples of AC signal〕

[0256] As examples of the AC signal, "the phase currents iu, iv, iw of the motor 60", "the phase voltages Vu, Vv, Vw of the motor 60", and "the cross-link fluxes Ψfu, Ψfv, Ψfw of the respective phases" can be given.

[0257] The interlinked magnetic fluxes Ψfu, Ψfv, and Ψfw of the respective phases can be expressed as follows.

[0258] (Math. 19)

[0259]

[0260] As another example of the alternating current signal, a fixed coordinate current, voltage, interlinked magnetic flux obtained by performing three-to-two phase conversion on the above-described alternating current signal can be given.

[0261] Also, the alternating current signal can be a line current, line-to-line voltage, or the like of the motor 60. Also, the alternating current signal can be a two-phase alternating current (for example, an α-axis current and a β-axis current) or a two-phase alternating voltage obtained by performing three-to-two phase conversion on a phase current, phase voltage, line current, and line-to-line voltage. Also, the alternating current can be a current flowing between a commercial power supply system (specifically, the alternating current power supply 5) and the inverter 21 of the motor drive device 20.

[0262] (Detailed example of the inference processing)

[0263] Next, a detailed example of the inference processing will be described. As examples of the inference processing, the following four inference processes (first to fourth inference processes) can be given. Hereinafter, a case where the inference processing is performed based on the amplitude of a specific frequency component will be described as an example. The "specific frequency component" in the following description is the "amplitude value of the specific frequency component".

[0264] Also, hereinafter, a value indicating the magnitude of the change over time of the specific frequency component included in the physical quantity related to the state of the compressor 50 will be referred to as an "index value". For example, in the inference processing, the control unit 31 derives the index value every predetermined processing period, and infers whether or not the state of the compressor 50 is the "state in which the specific frequency component rapidly changes" based on the comparison result of the index value and a threshold value.

[0265] [First inference process]

[0266] First, with reference to Figure 9 The first inference process will be described. The index value in the first inference process is a proportional value obtained by dividing the "first filter value F1 indicating the specific frequency component after the first filter processing" by the "second filter value F2 indicating the specific frequency component specified by the second filter". The time constant of the second filter is greater than the time constant of the first filter.

[0267] Note that if the time constant of the first filter is too large, it can be impossible to detect the change over time (change over 20 to 30 seconds) of the specific frequency component that occurs at the time of an abnormality (for example, at the time of a failure in the seal of the lubricating oil against the compression chamber 68). Therefore, for example, the time constant of the first filter can be set to "less than 21.556 seconds", and specifically, can be set to "3.59 seconds".

[0268] Also, if the time constant of the second filter is too small, the change in the index value (the above-described ratio value) at the time of an abnormality becomes small, approaching the time constant of the first filter. In contrast, if the time constant of the second filter is too large, the influence of the change over time of the rotational speed, pressure, and temperature of the motor 60 of the compressor 50 can become large. Therefore, for example, the time constant of the second filter can be set to "21.556 seconds or more and 215.56 seconds or less", and specifically, can be set to "64.67 seconds".

[0269] In the first inference processing, the control unit 31 determines whether or not the index value in the first inference processing (in this example, the ratio value obtained by dividing the "first filtered value Fl" by the "second filtered value F2") is lower than a threshold value determined in advance (in this example, a threshold value for detecting a sharp decrease in the specific frequency component). In the case where the index value is lower than the threshold value, the control unit 31 infers that the state of the compressor 50 is a "state in which the specific frequency component is sharply changing (in this example, a sharp decrease)". On the other hand, in the case where the index value is not lower than the threshold value, the control unit 31 infers that the state of the compressor 50 is not a "state in which the specific frequency component is sharply changing (in this example, a sharp decrease)".

[0270] Note that in the first inference processing, the control unit 31 can also infer whether or not the state of the compressor 50 is a "state in which the specific frequency component is sharply increasing". In this case as well, for example, when the index value exceeds a threshold value determined in advance (a threshold value for detecting a sharp increase in the specific frequency component), the control unit 31 can infer that the state of the compressor 50 is a "state in which the specific frequency component is sharply increasing".

[0271] Also, the index value in the first inference processing can be a difference value obtained by subtracting the "second filtered value F2" from the "first filtered value Fl".

[0272] Alternatively, the index value in the first inference processing can be a ratio value obtained by dividing the "second filtered value F2" by the "first filtered value Fl". In this case as well, for example, when the index value in the first inference processing exceeds a threshold value determined in advance (a threshold value for detecting a sharp decrease in the specific frequency component), the control unit 31 can infer that the state of the compressor 50 is a "state in which the specific frequency component is sharply changing (specifically, a sharp decrease)".

[0273] Alternatively, the index value in the first inference process can also be a difference value obtained by subtracting the "first filter value Fl" from the "second filter value F2". In this case as well, for example, when the index value in the first inference process exceeds a predetermined threshold value (a threshold value for detecting a sharp decrease in the specific frequency component), the control unit 31 infers that the state of the compressor 50 is the "state in which the specific frequency component is sharply changing (specifically, sharply decreasing)".

[0274] 〔Second Inference Process〕

[0275] Next, the second inference process will be described with reference to Figure 10 to the second inference process. The index value in the second inference process is a difference value obtained by subtracting the "average value of the specific frequency component in the predetermined period Ta from the second time t k to the first time t k to the second time t k-1 .

[0276] Note that if the predetermined period Ta is too long, it can be impossible to detect the temporal change (temporal change over 20 seconds to 30 seconds) in the specific frequency component that occurs at the time of an anomaly (for example, at the time of failure of the sealability of the lubricating oil with respect to the compression chamber 68). Therefore, for example, the predetermined period Ta can be set to "less than 60 seconds", and specifically can be set to "5 seconds".

[0277] Also, if the time T is too short, the change in the index value (the above-described difference value) at the time of an anomaly becomes small. In contrast, if the time T is too long, the influence of the temporal change in the rotational speed, the pressure, and the temperature of the motor 60 of the compressor 50 can become large. Therefore, for example, the time T can be set to "60 seconds or more and 600 seconds or less", and specifically can be set to "60 seconds".

[0278] In the second inference process, the control unit 31 determines whether the index value in the second inference process (in this example, the difference value obtained by subtracting the "second-time average value A2" from the "first-time average value Al") exceeds a predetermined threshold value (in this example, a threshold value for detecting a sharp increase in the specific frequency component). In the case where the index value exceeds the threshold value, the control unit 31 infers that the state of the compressor 50 is the "state in which the specific frequency component is sharply changing (in this example, sharply increasing)". On the other hand, in the case where the index value does not exceed the threshold value, the control unit 31 infers that the state of the compressor 50 is not the "state in which the specific frequency component is sharply changing (in this example, sharply increasing)".

[0279] Note that in the second inference processing, the control unit 31 can also infer whether the state of the compressor 50 is the "state in which the specific frequency component sharply decreases". In this case as well, for example, when the index value is lower than a predetermined threshold value (threshold value for detecting a sharp decrease in the specific frequency component), the control unit 31 infers that the state of the compressor 50 is the "state in which the specific frequency component sharply decreases".

[0280] Also, the index value in the second inference processing can be a ratio value obtained by dividing the "first-time average value Al" by the "second-time average value A2".

[0281] Alternatively, the index value in the second inference processing can be a difference value obtained by subtracting the "first-time average value Al" from the "second-time average value A2". In this case as well, for example, when the index value in the second inference processing is lower than a predetermined threshold value (threshold value for detecting a sharp increase in the specific frequency component), the control unit 31 infers that the state of the compressor 50 is the "state in which the specific frequency component sharply changes (specifically, sharply increases)".

[0282] Alternatively, the index value in the second inference processing can be a ratio value obtained by dividing the "second-time average value A2" by the "first-time average value Al". In this case as well, for example, when the index value in the second inference processing is lower than a predetermined threshold value (threshold value for detecting a sharp increase in the specific frequency component), the control unit 31 infers that the state of the compressor 50 is the "state in which the specific frequency component sharply changes (specifically, sharply increases)".

[0283] 〔Third Inference Processing〕

[0284] Next, the third inference processing will be described with reference to Figure 11 and Figure 12 The index value in the third inference processing is a ratio value obtained by dividing the "first moving average value MA1" which is a moving average value of the specific frequency component in a first period T1 ending at a predetermined time t i (for example, the current time) by the "second moving average value MA2" which is a moving average value of the specific frequency component in a second period T2 ending at the predetermined time t i . The second period T2 is longer than the first period T1.

[0285] Note that if the first period T1 is too long, it can be impossible to detect a change over time (change over 20 to 30 seconds) in the specific frequency component that occurs at the time of an anomaly (for example, at the time of a failure in the sealability of the lubricating oil with respect to the compression chamber 68). Therefore, for example, the first period T1 can be set to "less than 60 seconds", and specifically, can be set to "10 seconds".

[0286] Also, if the second period T2 is too short, the change in the index value (the above-mentioned ratio value) at the time of abnormality becomes small. On the contrary, if the second period T2 is too long, the influence of the change over time of the rotation speed, the pressure, and the temperature of the motor 60 of the compressor 50 can become large. Therefore, for example, the second period T2 can be set to "60 seconds or more and 600 seconds or less", and specifically, can be set to "180 seconds".

[0287] In the third inference processing, the control unit 31 determines whether or not the index value (in this example, a ratio value obtained by dividing the "first moving average value MA1" by the "second moving average value MA2") in the third inference processing exceeds a threshold value (in this example, a threshold value for detecting a sharp rise in the specific frequency component) determined in advance. In a case where the index value exceeds the threshold value, the control unit 31 infers that the state of the compressor 50 is the "state in which the specific frequency component sharply changes (in this example, a sharp rise)". On the other hand, in a case where the index value does not exceed the threshold value, the control unit 31 infers that the state of the compressor 50 is not the "state in which the specific frequency component sharply changes (in this example, a sharp rise)".

[0288] Note that, in the third inference processing, the control unit 31 can also infer whether or not the state of the compressor 50 is the "state in which the specific frequency component sharply decreases". In this case as well, for example, when the index value is lower than a threshold value (a threshold value for detecting a sharp decrease in the specific frequency component) determined in advance, the control unit 31 can infer that the state of the compressor 50 is the "state in which the specific frequency component sharply decreases".

[0289] The index value in the third inference processing can also be a difference value obtained by subtracting the "second moving average value MA2" from the "first moving average value MA1".

[0290] Alternatively, the index value in the third inference processing can also be a ratio value obtained by dividing the "second moving average value MA2" by the "first moving average value MA1". In this case as well, for example, when the index value in the third inference processing is lower than a threshold value (a threshold value for detecting a sharp rise in the specific frequency component) determined in advance, the control unit 31 can infer that the state of the compressor 50 is the "state in which the specific frequency component sharply changes (specifically, a sharp rise)".

[0291] Alternatively, the index value in the third inference processing can also be a difference value obtained by subtracting the "first moving average value MA1" from the "second moving average value MA2". In this case as well, for example, when the index value in the third inference processing is lower than a threshold value (a threshold value for detecting a sharp rise in the specific frequency component) determined in advance, the control unit 31 can infer that the state of the compressor 50 is the "state in which the specific frequency component sharply changes (specifically, a sharp rise)".

[0292] 〔Fourth inference processing〕

[0293] Next, the fourth inference processing will be described with reference to Figure 13 The index value in the fourth inference processing is a ratio value obtained by dividing the instantaneous value X of the specific frequency component at the prescribed time t i (for example, the current time) by the average value AA of the specific frequency component in the prescribed period Tb ending at the prescribed time t i

[0294] Note that if the prescribed period Tb is too short, the change in the index value (the difference described above) at the time of anomaly becomes small. On the contrary, if the prescribed period Tb is too long, the influence of the change over time of the rotation speed, pressure, and temperature of the motor 60 of the compressor 50 can become large. Therefore, for example, the prescribed period Tb can be set to "60 seconds or more and 600 seconds or less", and specifically, can be set to "180 seconds".

[0295] In the fourth inference processing, the control unit 31 determines whether the index value in the fourth inference processing (in this example, the ratio value obtained by dividing the instantaneous value X by the average value AA) is lower than a threshold value determined in advance (in this example, a threshold value for detecting a sharp decrease in the specific frequency component). In the case where the index value is lower than the threshold value, the control unit 31 infers that the state of the compressor 50 is "a state in which the specific frequency component is sharply changed (in this example, a sharp decrease)". On the other hand, in the case where the index value is not lower than the threshold value, the control unit 31 infers that the state of the compressor 50 is not "a state in which the specific frequency component is sharply changed (in this example, a sharp decrease)".

[0296] Note that in the fourth inference processing, the control unit 31 can also infer whether the state of the compressor 50 is "a state in which the specific frequency component is sharply increased". In this case as well, for example, when the index value exceeds a threshold value determined in advance (a threshold value for detecting a sharp increase in the specific frequency component), the control unit 31 can infer that the state of the compressor 50 is "a state in which the specific frequency component is sharply increased".

[0297] Also, the index value in the fourth inference processing can be a difference value obtained by subtracting the average value AA from the instantaneous value X.

[0298] Alternatively, the index value in the fourth inference processing can be a ratio value obtained by dividing the average value AA by the instantaneous value X. In this case as well, for example, when the index value in the fourth inference processing exceeds a threshold value determined in advance (a threshold value for detecting a sharp decrease in the specific frequency component), the control unit 31 can infer that the state of the compressor 50 is "a state in which the specific frequency component is sharply changed (specifically, a sharp decrease)".

[0299] ​Alternatively, the index value in the fourth inference process can also be a difference value obtained by subtracting the "instantaneous value X" from the "average value AA". In this case, the control unit 31 can also infer that the state of the compressor 50 is the "state in which the specific frequency component is rapidly changing (specifically, rapidly decreasing)" when the index value in the fourth inference process exceeds a predetermined threshold value (threshold value for detecting a rapid decrease in the specific frequency component).

[0300] (Refrigeration system)

[0301] Figure 14 The structure of a refrigeration system RR is exemplified. The refrigeration system RR is provided with a refrigerant circuit RR1 filled with a refrigerant, a motor drive device 20, and a control device 30.

[0302] The refrigerant circuit RR1 has a compressor 50, a heat radiator 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 refrigeration cycle.

[0303] The compressor 50 has a compression mechanism 65 and a motor 60. The compression mechanism 65 is coupled to the motor 60 through a drive shaft. The motor 60 rotationally drives the compression mechanism 65 by rotationally driving the drive shaft. The motor drive device 20 drives the motor 60.

[0304] In the refrigeration cycle, the refrigerant flowing out of the compressor 50 is heat radiated in the heat radiator RR5. The refrigerant flowing out of the heat radiator RR5 is pressure-reduced in the pressure reducing mechanism RR6 and evaporated in the evaporator RR7. Then, the refrigerant having flowed out of the evaporator RR7 flows into the compressor 50.

[0305] In this example, the refrigeration system RR is an air conditioner. The air conditioner can be a refrigeration-only machine or a heating-only machine. Also, the air conditioner can be an air conditioner that switches between refrigeration and heating. In this case, the air conditioner has a switching mechanism (for example, a four-way reversing valve) that switches the circulation direction of the refrigerant. Also, the refrigeration system RR can be a water heater, a cooling unit, a cooling device that cools air in a warehouse, or the like. The cooling device cools air inside a refrigerated warehouse, a freezer, a container, or the like.

[0306] (Insights obtained through experiments)

[0307] Next, experiments performed by the present inventors and insights obtained through the experiments are described with reference to Figure 15 and Figure 16 .

[0308] As Figure 15In the experiment, the amplitude value of the "specific frequency component" included in the physical quantity (in this case, the current vector amplitude Ia) obtained during 10 seconds is derived every 1 second. Then, 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 is taken as the "index value". If the index value is expressed by an equation, it becomes "|1 - (MA1 / MA2)|". The above index value can be said to be a modification example of the index value in the third estimation process.

[0309] In addition, the first moving average MA1 is an average value of 10 amplitude values derived in a first period T1 of 10 seconds ending at the time ti at which the latest amplitude value is derived. The second moving average MA2 is an average value of 180 amplitude values derived in a second period T2 of 3 minutes ending at the time ti at which the latest amplitude value is derived. For example, the first period T1 and the second period T2 can be illustrated as Figure 12

[0310] Also, in the experiment, the state of the compressor 50 is set to a predetermined "stable state". Note that the stable state of the compressor 50 refers to a state other than a prescribed state (a state in which the specific frequency component changes sharply) and refers to a state in which the compressor 50 is operated under a predetermined operating condition (a stable operating condition). For example, the stable state of the compressor 50 is a state that satisfies all of the following conditions.

[0311] (1) The suction port 101a of the oil supply path 100 is immersed in the lubricating oil accumulated in the oil storage portion 54.

[0312] (2) The working fluid in a gaseous state is sucked into the compressor 50.

[0313] (3) The rotation frequency of the motor 60 of the compressor 50 is in a stable state.

[0314] (4) The pressure of the working fluid ejected from the compressor 50 is in a stable state.

[0315] (5) The pressure of the working fluid sucked into the compressor 50 is in a stable state.

[0316] (6) The temperature of the working fluid ejected from the compressor 50 is in a stable state.

[0317] (7) The temperature of the working fluid sucked into the compressor 50 is in a stable state.

[0318] Note that the above stable state can also be determined based on the purpose of the compressor 50 or the like.

[0319] As Figure 16 ​The index value observed when the compressor 50 is in the steady state is a value lower than "0.1". When the compressor 50 changes from the steady state to the predetermined state (a state in which the specific frequency component changes sharply), the index value exceeds "0.1" and rises to a maximum value (for example, around 3.5). Also, even when the compressor 50 is in the steady state, the index value slightly fluctuates. If the index values included in a measurement period of 10 minutes are observed, the peak value (maximum value) of the slight fluctuation of the index value can be observed.

[0320] Also, in order to verify the influence of individual differences of the compressor 50, the operation of replacing the compressor 50 provided in the refrigeration system RR with another compressor 50 (a compressor 50 of the same model) and observing the above index value was repeatedly performed. As a result, regardless of the individual differences of the compressor 50, the index value when the compressor 50 is in the steady state is a value lower than "0.1".

[0321] Through the above experiments, the present inventors obtained the following insights. Also, in the following, the following conditions will be described as "verification conditions": the amplitude value of the specific frequency component included in the physical quantity obtained in a period of 10 seconds is derived every 1 second, the average value of 10 amplitude values derived in a first period T1 of 10 seconds ending at the time ti at which the latest amplitude value is derived is set as a "first moving average value MA1", the average value of 180 amplitude values derived in a second period T2 of 3 minutes ending at the time ti at which the latest amplitude value is derived is set as a "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 set as an "index value".

[0322] The present inventors found that, under the above verification conditions, by setting a threshold value for the above index value to be "a value 1.1 times or more of the maximum value of the index value obtained in a measurement period of 10 minutes under the condition that the compressor 50 is in a predetermined steady state" or "0.1", in the case where the above index value exceeds the above threshold value, it can be inferred that the state of the compressor 50 is a predetermined state (a state in which the specific frequency component changes sharply).

[0323] Also, by setting the threshold value for the index value in each of the first to fourth inference processes as follows, it is possible to perform the coping process at the same timing as in the case where the threshold value for the above index value (the absolute value of the difference between the value obtained by dividing the first moving average value MA1 by the second moving average value MA2 and 1) is set to "0.1". Hereinafter, the "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", that is, the index value, will be described as a "reference index value".

[0324] 〔Threshold value for the index value in the first inference processing〕

[0325] In the case where the index value is a ratio value obtained by dividing the first filter value Fl by the second filter value F2, the threshold value is set to a range of "0.89 to 1.11". If the index value departs from the above range, the reference index value exceeds "0.1".

[0326] Also, in the case where the index value is an absolute value of a difference between the ratio value obtained by dividing the first filter value Fl by the second filter value F2 and 1, the threshold value is set to "0.11". If the index value exceeds the above threshold value, the reference index value exceeds "0.1".

[0327] 〔Threshold value for the index value in the second inference processing〕

[0328] In the case where the index value is a difference value obtained by subtracting the second-time average value A2 from the first-time average value Al, the threshold value is set to a range of "-0.25 to +0.25". If the index value departs from the above range, the reference index value exceeds "0.1".

[0329] 〔Threshold value for the index value in the third inference processing〕

[0330] In the case where the index value is a ratio value obtained by dividing the first moving average value MAI by the second moving average value MA2, the threshold value is set to a range of "0.9 to 1.1". If the index value departs from the above range, the reference index value exceeds "0.1".

[0331] 〔Threshold value for the index value in the fourth inference processing〕

[0332] In the case where the index value is a ratio value obtained by dividing the instantaneous value X of the specific frequency component by the average value AA of the specific frequency component within the prescribed period Tb, the threshold value is set to a range of "0.69 to 1.31". If the index value departs from the above range, the reference index value exceeds "0.1".

[0333] Also, in the case where the index value is an absolute value of a difference between the ratio value obtained by dividing the instantaneous value X of the specific frequency component by the average value AA of the specific frequency component within the prescribed period Tb and 1, the threshold value is set to "0.31". If the index value exceeds the above threshold value, the reference index value exceeds "0.1".

[0334] (Other Embodiments)

[0335] In the above description, as an example of physical quantities related to the state of motor 60, signals representing physical quantities related to the voltage or current of motor 60 were listed, but the description is not limited to this. For example, the physical quantity could be a signal representing the vibration of motor 60, or a signal representing the sound of motor 60. The signal representing the vibration of motor 60 could also be obtained by a vibration sensor (not shown) installed in compressor 50 or device 1. The signal representing the sound of motor 60 could also be obtained by a microphone (not shown) installed in compressor 50 or device 1. The sound could be sound within the audible range or sound outside the audible range (ultrasound). Thus, the physical quantity could be any physical quantity among the rotational frequency of motor 60, the voltage applied to motor 60, the current flowing through motor 60, the vibration of compressor 50, the sound of compressor 50, and the sound around compressor 50.

[0336] Furthermore, as described above, the control unit 31 may also be configured to perform inference processing using a neural network or an algorithm constructed through machine learning (an algorithm for inferring the state based on changes in signals).

[0337] Furthermore, as described above, the control unit 31 can be implemented by one processor or by multiple processors. Additionally, the control unit 31 can also be implemented by multiple arithmetic processing devices (computers) that communicate with each other via a communication network.

[0338] Furthermore, the above explanation uses the case of compressor 50 being a "scroll compressor" as an example, but it is not limited to this. For example, compressor 50 can be an oscillating compressor in which the piston and vanes are integrated, a rotary compressor in which the piston and vanes are separate parts, or other types of rotary compressors.

[0339] Furthermore, compressor 50 can also be a twin-cylinder compressor (oscillating compressor or rotary compressor) with two compression chambers.

[0340] like Figure 17 As shown, the torque pulsation period of the twin-cylinder compressor (the pulsation period during normal operation) corresponds to half the rotational period of the motor 60. Furthermore, in the twin-cylinder compressor, when liquid compression occurs, the abrupt change in compressor torque occurs with a period corresponding to half the rotational period of the motor 60. Therefore, in the twin-cylinder compressor, when liquid compression occurs, the secondary component of the compressor 50's torque changes abruptly (specifically, increases abruptly), resulting in abrupt changes (specifically, increases abruptly) of the secondary component of the current vector amplitude Ia. It should be noted that the "secondary component" refers to a frequency component with a frequency twice the mechanical angular frequency of the motor 60.

[0341] In the case where the compressor 50 is a "double-cylinder type compressor", the "specific frequency component handled in the inference processing" can also be a "second-order component". Thereby, it is possible to infer whether or not the state of the compressor 50 is a "liquid compression state".

[0342] Also, in the above description, the various sensors can be contact-type sensors or non-contact-type sensors. The contact-type sensors can be installed to the casing 51 of the compressor 50 or to a pipe or an electric wire provided in the vicinity of the compressor 50. The non-contact-type sensors can be installed at a place near the casing 51 of the compressor 50, at a place near a pipe or an electric wire provided in the vicinity of the compressor 50, at a place near the device 1 in which the compressor 50 is mounted, or the like.

[0343] Also, in the above description, the detection unit that detects information on a physical quantity related to the state of the compressor 50 can be a single sensor or a combination of a plurality of sensors.

[0344] Also, in the above description, the change processing can also be "change processing that changes an operation condition of a system that includes the compressor 50". In the change processing, not only the operation condition of the motor 60 but also the operation condition of "another component other than the motor 60" included in the system that includes the compressor 50 can be changed. As examples of the change processing, there can be mentioned processing that stops the motor 60, processing that accelerates the motor 60, processing that decelerates the motor 60, processing that reduces the current flowing through the motor 60, processing that increases the current flowing through the motor 60, processing that increases the opening degree of an expansion valve (an electric valve) that constitutes a pressure reducing mechanism RR6, processing that decreases the opening degree of the expansion valve (the electric valve) that constitutes the pressure reducing mechanism RR6, processing that increases the pressure of working fluid discharged from the compressor 50, processing that decreases the pressure of the working fluid discharged from the compressor 50, processing that increases the temperature of the working fluid discharged from the compressor 50, processing that decreases the temperature of the working fluid discharged from the compressor 50, processing that returns lubricating oil flowing in a fluid flow path to the compressor 50 together with the working fluid, processing that increases the rotation speed of a fan (not shown) that transports air to the heat radiator RR5 or the evaporator RR7, processing that decreases the rotation speed of the fan that transports air to the heat radiator RR5 or the evaporator RR7, and the like.

[0345] Also, the embodiments and the modified examples are described, but it is understood that various changes in the modes and details can be made without departing from the gist and scope of the claims. Also, the elements of the above embodiments, the modified examples, other embodiments can be appropriately combined or replaced.

[0346] (Summary of Embodiments)

[0347] Summarizing the above description, the control device of the embodiment relates to a control device that controls a system that has a compressor 50 having a motor 60 and a compression mechanism 65. The control device has a control section 31. In a case where a relationship between an index value that indicates a magnitude of a change over time of a specific frequency component included in a physical quantity related to a state of the compressor 50 and a predetermined threshold value becomes a prescribed relationship, the control section 31 performs a coping process including at least one of an output process of outputting information indicating that the state of the compressor 50 is a prescribed state and a change process of changing an operation condition of the system.

[0348] The inventors of the present application have conducted intensive research and as a result, have found that there is a state in which a specific frequency component included in a physical quantity related to a state of a compressor 50 changes sharply in the state of the compressor 50 having a motor 60 and a compression mechanism 65. Furthermore, the inventors of the present application have found that such a state (a state of the compressor 50 in which the specific frequency component changes sharply) can be inferred on the basis of a magnitude of a change over time of the specific frequency component included in the physical quantity.

[0349] In the above-described structure, by performing a coping process in a case where a relationship between an index value that indicates a magnitude of a change over time of a specific frequency component included in a physical quantity related to a state of a compressor 50 and a predetermined threshold value becomes a prescribed relationship, it is possible to appropriately perform a process for coping with a case where the state of the compressor 50 is a prescribed state (a state in which the specific frequency component changes sharply).

[0350] In addition, the control section 31 can also be configured to perform a coping process in a case where the index value is set to an absolute value of a difference between a value obtained by dividing a first moving average value MA1 by a second moving average value MA2 and 1, the first moving average value MA1 is set to an average value of 10 amplitude values that are derived in a first period T1 of 10 seconds that ends at a time ti at which the latest amplitude value is derived, the second moving average value MA2 is set to an average value of 180 amplitude values that are derived in a second period T2 of 3 minutes that ends at the time ti at which the latest amplitude value is derived, and the threshold value is set to a value that is 1.1 times or more of a maximum value of the index value that is obtained in a measurement period of 10 minutes under the condition that the compressor 50 is in a predetermined stable state, when the index value exceeds the threshold value.

[0351] The present inventors have conducted intensive research, and as a result, have found that by setting the threshold value for the index value to "a value of 1.1 times or more of 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", in the case where the index value exceeds the threshold value, it can be inferred that the state of the compressor 50 is the prescribed state (a state in which the specific frequency component rapidly changes).

[0352] In the above structure, by performing the coping process in the case where the index value exceeds the threshold value, the process for coping with the case where the state of the compressor 50 is the prescribed state (a state in which the specific frequency component rapidly changes) can be appropriately performed.

[0353] Also, the control section 31 can be configured to perform the coping process in the case where the index value exceeds the threshold value, under the condition that the amplitude value of the specific frequency component included in the physical quantity obtained during a 10-second period is derived every 1 second, the index value is set to "an absolute value of the difference between a value obtained by dividing the first moving average value MA1 by the second moving average value MA2 and 1", the first moving average value MA1 is set to "an average value of 10 amplitude values derived during a first period T1 of 10 seconds ending at the time ti at which the latest amplitude value is derived", the second moving average value MA2 is set to "an average value of 180 amplitude values derived during a second period T2 of 3 minutes ending at the time ti at which the latest amplitude value is derived", and the threshold value is set to "0.1".

[0354] The present inventors have conducted intensive research, and as a result, have found that by setting the threshold value for the index value to "0.1", in the case where the index value exceeds the threshold value, it can be inferred that the state of the compressor 50 is the prescribed state (a state in which the specific frequency component rapidly changes).

[0355] In the above structure, by performing the coping process in the case where the index value exceeds the threshold value, the process for coping with the case where the state of the compressor 50 is the prescribed state (a state in which the specific frequency component rapidly changes) can be appropriately performed.

[0356] Also, the compression mechanism 65 can have a compression chamber 68 for compressing the working fluid. The compression chamber 68 can also be sealed by the lubricating oil. The prescribed state can be a state in which the sealing property of the lubricating oil to the compression chamber 68 is lost.

[0357] The present inventors have conducted intensive research, and as a result, have found the phenomenon that "when the sealing property of the lubricating oil to the compression chamber 68 is lost in the compressor 50, the specific frequency component included in the physical quantity related to the state of the compressor 50 rapidly changes".

[0358] In the above structure, processing for coping with a case where the state of the compressor 50 is "a state where the sealability of the lubricating oil to the compression chamber 68 is failed" can be appropriately performed.

[0359] Also, the compression mechanism 65 can have a compression chamber 68 for compressing the working fluid. The compressor 50 can have an oil storage portion 54 that stores the lubricating oil and an oil supply path 100 for supplying the lubricating oil stored in the oil storage portion 54 to the compression chamber 68. The oil supply path 100 can have a suction port 101a that is immersed in the lubricating oil stored in the oil storage portion 54, so that the lubricating oil sucked from the suction port 101a can be supplied to the compression chamber 68. The compression chamber 68 can be sealed by the lubricating oil. The prescribed state can be a state where the suction port 101a of the oil supply path 100 is not immersed in the lubricating oil stored in the oil storage portion 54.

[0360] The present inventors have conducted intensive studies and as a result, have found the following phenomenon: "When the suction port 101a of the oil supply path 100 is no longer immersed in the lubricating oil stored in the oil storage portion 54 in the compressor 50, the sealability of the lubricating oil to the compression chamber 68 is failed, and as a result, a specific frequency component included in a physical quantity related to the state of the compressor 50 is sharply changed".

[0361] In the above structure, processing for coping with a 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 stored in the oil storage portion 54" can be appropriately performed.

[0362] Also, the prescribed state can be a liquid compression state where the working fluid in a liquid state is sucked into the compression mechanism 65 and compressed in the compression mechanism 65.

[0363] The present inventors have conducted intensive studies and as a result, have found the following phenomenon: "When the working fluid in a liquid state 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 related to the state of the compressor 50 is sharply changed".

[0364] In the above structure, processing for coping with a case where the state of the compressor 50 is "a liquid compression state where the working fluid in a liquid state is sucked into the compression mechanism 65 and compressed in the compression mechanism 65" can be appropriately performed.

[0365] Also, the control method of the embodiment relates to a control method of controlling a system provided with a compressor 50 having a motor 60 and a compression mechanism 65. The control method is provided with a step of acquiring and a step of coping. In the step of acquiring, a physical quantity related to a state of the compressor 50 is acquired. In the step of coping, in a case where a relationship between an index value indicating a magnitude of a change over time of a specific frequency component included in the physical quantity acquired in the step of acquiring and a predetermined threshold value becomes a prescribed relationship, at least one of an output step of outputting information indicating that the state of the compressor 50 is a prescribed state and a change step of changing an operation condition of the system is performed.

[0366] In the above-described method, by performing the step of coping in a case where the relationship between the index value indicating the magnitude of the change over time of the specific frequency component included in the physical quantity related to the state of the compressor 50 and the predetermined threshold value becomes the prescribed relationship, it is possible to appropriately perform processing for coping with a case where the state of the compressor 50 is the prescribed state (a state in which the specific frequency component sharply changes).

[0367] Industrial applicability

[0368] As described above, the present disclosure is useful as a control technique.

[0369] Explanation of reference numerals

[0370] 1 device

[0371] 5 power supply

[0372] 10 drive system

[0373] 20 motor drive device

[0374] 21 inverter

[0375] 22 direct current portion

[0376] 23 inverter (conversion portion)

[0377] 30 control device (state inferring device)

[0378] 31 control portion

[0379] 41 phase current detecting portion

[0380] 42 electric angle frequency detecting portion

[0381] 50 compressor

[0382] 54 oil storage portion

[0383] 60 motor

[0384] 65 compression mechanism

[0385] 68 compression chamber

[0386] 100 oil supply path

[0387] 101a suction port

[0388] RR refrigeration system

[0389] RR1 refrigerant circuit

Claims

1. A control device for controlling a system having a compressor (50), said compressor (50) having a motor (60) and a compression mechanism (65), wherein, The control device includes a control unit (31) that performs a response process when the relationship between an index value representing the magnitude of the change of a specific frequency component of a physical quantity related to the state of the compressor (50) over time and a predetermined threshold value becomes a predetermined relationship. The response process includes at least one of output processing that outputs information indicating that the state of the compressor (50) is a predetermined state and change processing that changes the operating conditions of the system.

2. The control device according to claim 1, wherein, Under the condition of deriving the amplitude values ​​of the specific frequency components included in the physical quantity obtained over a period of 10 seconds every 1 second, When the index value is set as the absolute value of the difference between the first moving average (MA1) and the second moving average (MA2) and 1, the first moving average (MA1) is set as the average of 10 amplitude values ​​derived within a first period (T1) of 10 seconds terminating at the time (ti) at which the latest amplitude value is derived, the second moving average (MA2) is set as the average of 180 amplitude values ​​derived within a second period (T2) of 3 minutes terminating at the time (ti) at which the latest amplitude value is derived, and the threshold is set as a value greater than 1.1 times 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 stable state, The control unit (31) performs the response processing when the index value exceeds the threshold.

3. The control device according to claim 1, wherein, Under the condition of deriving the amplitude values ​​of the specific frequency components included in the physical quantity obtained over a period of 10 seconds every 1 second, The index value is set as the absolute value of the difference between the first moving average (MA1) divided by the second moving average (MA2) and 1; the first moving average (MA1) is set as the average of 10 amplitude values ​​exported within a first period (T1) of 10 seconds with the latest amplitude value exported as the terminal; the second moving average (MA2) is set as the average of 180 amplitude values ​​exported within a second period (T2) of 3 minutes with the latest amplitude value exported as the terminal; and the threshold is set to 0.

1. The control unit (31) performs the response processing when the index value exceeds the threshold.

4. The control device according to any one of claims 1 to 3, wherein, The compression mechanism (65) has a compression chamber (68) for compressing the working fluid. The compression chamber (68) is sealed with lubricating oil. The specified state is the state in which the lubricating oil fails to seal the compression chamber (68).

5. The control device according to any one of claims 1 to 3, wherein, The compression mechanism (65) has a compression chamber (68) for compressing the working fluid. The compressor (50) has: an oil storage section (54) for storing lubricating oil; and an oil supply path (100) for supplying the lubricating oil stored in the oil storage section (54) to the compression chamber (68). The oil supply path (100) has an intake port (101a), which, by immersing the intake port (101a) in the lubricating oil accumulated in the oil storage section (54), can supply the lubricating oil drawn in from the intake port (101a) to the compression chamber (68). The compression chamber (68) is sealed by the lubricating oil. The specified state is that the intake port (101a) of the oil supply path (100) is not immersed in the lubricating oil accumulated in the oil storage section (54).

6. The control device according to any one of claims 1 to 3, wherein, The specified state is a liquid compression state in which the liquid working fluid is drawn into the compression mechanism (65) and compressed in the compression mechanism (65).

7. The control device according to any one of claims 1 to 6, wherein, The physical quantity is any physical quantity among 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).

8. The control device according to any one of claims 1 to 7, wherein, The frequency of the specific frequency component is a frequency synchronized with the rotational frequency of the motor (60).

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

10. A control method for controlling a system having a compressor (50), said compressor (50) having a motor (60) and a compression mechanism (65), wherein, The control method comprises: The acquisition step involves acquiring physical quantities related to the state of the compressor (50); and The response step includes at least one of the following steps: when the relationship between the index value representing the magnitude of the change over time of a specific frequency component included in the physical quantity obtained in the acquisition step and a predetermined threshold is defined, an output step representing the state of the compressor (50) as defined, and a change step changing the operating conditions of the system.

11. A control program that causes a computer to execute the control method of claim 10.

Images