State estimation device, drive system, refrigeration system, fan system, state estimation method, and state estimation program

Abstract

In the calculation process, the control unit (31) calculates the feature quantity on the basis of a physical quantity obtained from the device (70) for a predetermined period of time. In the estimation process, the control unit (31) estimates the state of the device (70) on the basis of the feature amount calculated by the calculation process. In the limiting process, the control unit (31) limits the estimation process when the estimated limiting condition is satisfied, maintains the limitation on the estimation process until the standby release condition is satisfied when the limitation release condition is satisfied, and releases the limitation on the estimation process after the standby release condition is satisfied. The estimation restriction condition is a condition that has a possibility of erroneous estimation occurring in the estimation processing. The restriction release condition is a condition that makes it possible to suppress erroneous estimation in the estimation processing.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a state inference technology. BACKGROUND

[0002] Patent Literature 1 discloses an abnormality diagnosing device of a rotating machine driven by an electric motor. The abnormality diagnosing device includes a parameter acquisition section that acquires a parameter indicating a frequency spectrum shape from a frequency spectrum obtained based on a current value of the electric motor, and an abnormality judging section that diagnoses an abnormality of the rotating machine based on the parameter.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2020-67334 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the case of a state inference device (a device that infers a state of an apparatus) like the abnormality diagnosing device in Patent Literature 1, if a characteristic quantity used for inferring the state of the apparatus undergoes an unexpected variation (noise), it is difficult to accurately infer the state of the apparatus from the characteristic quantity, and the state of the apparatus can be erroneously inferred. For example, when the state inference device infers whether the apparatus is abnormal, the apparatus can be erroneously inferred as abnormal although the apparatus is normal.

[0008] SOLUTION TO THE PROBLEMS

[0009] A first aspect of the present disclosure relates to a state inferring apparatus that infers a state of an apparatus 70 having a motor 50, the state inferring apparatus including a control section 31. The control section 31 performs a calculation process in which a characteristic quantity is calculated from a physical quantity obtained from the apparatus 70 over a prescribed period, an inference process in which the state of the apparatus 70 is inferred from the characteristic quantity calculated by the calculation process, and a restriction process in which, when a prescribed inference restriction condition is satisfied, the inference process is restricted so as to output a preset inference result, when a prescribed restriction release condition is satisfied, the restriction on the inference process is maintained until a prescribed standby release condition is satisfied, and after the prescribed standby release condition is satisfied, the restriction on the inference process is released. The physical quantity is a quantity that varies in accordance with rotation of the motor 50. The characteristic quantity is a quantity that varies in accordance with the state of the apparatus 70. The state of the apparatus 70 includes at least one of an abnormality of the motor 50, a degree of deterioration of the motor 50, an abnormality of a component driven by the motor 50, and a degree of deterioration of the component driven by the motor 50. The inference restriction condition is a condition in which there is a possibility that a false inference will occur in the inference process. The restriction release condition is a condition in which a false inference in the inference process can be suppressed.

[0010] In the first aspect, when the prescribed inference restriction condition is satisfied, the inference process is restricted so as to output a preset inference result, whereby a false inference of the state of the apparatus 70 can be appropriately suppressed. Further, by restricting the inference process in accordance with satisfaction of the prescribed restriction release condition, the restriction on the inference process can be appropriately released.

[0011] Further, in the first aspect, when the prescribed restriction release condition is satisfied, the restriction on the inference process is maintained until the prescribed standby release condition is satisfied, and after the prescribed standby release condition is satisfied, the restriction on the inference process is released. In this way, compared to a case in which the restriction on the inference process is released without waiting for the prescribed standby release condition to be satisfied, the restriction on the inference process can be released after the characteristic quantity calculated in the calculation process has stabilized. In this way, a false inference of the state of the apparatus 70 can be suppressed after the restriction on the inference process is released.

[0012] A second aspect of the present disclosure is based on the state inferring apparatus of the first aspect of the present disclosure, in which the restriction release condition is a condition in which a rotational speed of the motor 50 changes from a non-stable state to a stable state.

[0013] In the second aspect, the state of the rotation speed of the electric motor 50 is related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the state of the rotation speed of the electric motor 50, it is possible to confirm whether or not the characteristic quantity has undergone an unexpected change. Therefore, by releasing the restriction on the inference processing in accordance with a change in the state of the rotation speed of the electric motor 50, it is possible to appropriately release the restriction on the inference processing.

[0014] The third aspect of the present disclosure is based on the state inferring apparatus of the first aspect of the present disclosure, the device 70 includes a compressor CC having the electric motor 50, and the restriction release condition is a condition in which the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from an unstable state to a stable state.

[0015] In the third aspect, the state of the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC is related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the state of the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC, it is possible to confirm whether or not the characteristic quantity has undergone an unexpected change. Therefore, by releasing the restriction on the inference processing in accordance with a change in the state of the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC, it is possible to appropriately release the restriction on the inference processing.

[0016] The fourth aspect of the present disclosure is based on the state inferring apparatus of the first aspect of the present disclosure, the device 70 includes a compressor CC having the electric motor 50, and the restriction release condition is a condition in which the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from an unstable state to a stable state.

[0017] In the fourth aspect, the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC is related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC, it is possible to confirm whether or not the characteristic quantity has undergone an unexpected change. Therefore, by releasing the restriction on the inference processing in accordance with a change in the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC, it is possible to appropriately release the restriction on the inference processing.

[0018] The fifth aspect of the present disclosure is based on the state inferring apparatus of the first aspect of the present disclosure, the release condition of the restriction is a first condition or a second condition, the first condition is that the control mode of the motor 50 is changed after the inferring process is restricted, and the second condition is that when the inferring restriction condition is the condition that the control mode of the motor 50 is changed, the inferring process is restricted according to the change of the control mode of the motor 50.

[0019] In the fifth aspect, the change of the control mode of the motor 50 is related to the unexpected change of the characteristic quantity calculated from the physical quantity obtained from the device 70 within a predetermined period. By monitoring the change of the control mode of the motor 50, it can be confirmed whether the characteristic quantity has an unexpected change. Therefore, by releasing the restriction on the inferring process according to the change of the control mode of the motor 50, the restriction on the inferring process can be appropriately released.

[0020] The sixth aspect of the present disclosure is based on the state inferring apparatus of the first aspect of the present disclosure, the motor 50 is driven by alternating current, the alternating current is generated based on the power supply power supplied from the power supply 60, and the release condition of the restriction is the condition that the integer multiple or the M / N multiple (M, N are integers) of the rotation frequency of the motor 50 deviates from the integer multiple of the frequency of the voltage of the power supply 60.

[0021] In the sixth aspect, the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotation frequency of the motor 50 is related to the unexpected change of the characteristic quantity calculated from the physical quantity obtained from the device 70 within a predetermined period. By monitoring the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotation frequency of the motor 50, it can be confirmed whether the characteristic quantity has an unexpected change. Therefore, by releasing the restriction on the inferring process according to the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotation frequency of the motor 50, the restriction on the inferring process can be appropriately released.

[0022] The seventh aspect of the present disclosure is based on the state inferring apparatus of the first aspect of the present disclosure, the motor 50 is driven by the motor drive apparatus 20, the motor drive apparatus 20 has a direct current part 22 and a conversion part 23, the direct current part 22 generates direct current corresponding to the power supply power supplied from the power supply 60, and the conversion part 23 converts the direct current generated by the direct current part 22 into alternating current through switching operation, and the release condition of the restriction is the condition that the voltage of the direct current part 22 changes from a non-stable state to a stable state.

[0023] In the seventh aspect, the state of the voltage of the direct current section 22 is related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the state of the voltage of the direct current section 22, it is possible to confirm whether or not the characteristic quantity has undergone an unexpected change. Therefore, by releasing the restriction on the inference processing in accordance with a change in the state of the voltage of the direct current section 22, it is possible to appropriately release the restriction on the inference processing.

[0024] The eighth aspect of the present disclosure is based on the state inferring apparatus of the first aspect of the present disclosure, the device 70 includes a compressor CC having the motor 50, the release condition includes at least two of a first release condition, a second release condition, a third release condition, a fourth release condition, a fifth release condition, and a sixth release condition, the first release condition is that the rotation speed of the motor 50 changes from a non-stable state to a stable state, the second release condition is that the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from a non-stable state to a stable state, the third release condition is that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from a non-stable state to a stable state, the fourth release condition is the first condition or the second condition, the first condition is that the control mode of the motor 50 changes after the inference processing is restricted, the second condition is that when the inference release condition is the condition that the control mode of the motor 50 changes, the inference processing is restricted in accordance with the change in the control mode of the motor 50, the fifth release condition is that when the motor 50 is driven by alternating current generated based on the power supply electric power supplied from the power supply 60, an integer multiple or M / N (M, N are integers) of the rotation frequency of the motor 50 deviates from an integer multiple of the frequency of the voltage of the power supply 60, and the sixth release condition is that the motor drive apparatus 20 has a direct current section 22 that generates direct current corresponding to the power supply electric power supplied from the power supply 60 and a conversion section 23 that converts the direct current generated by the direct current section 22 into alternating current through switching operation, the voltage of the direct current section 22 changes from a non-stable state to a stable state when the motor 50 is driven by the motor drive apparatus 20, and the release condition is satisfied when all the conditions included in the release condition are satisfied.

[0025] In the eighth aspect, the following (1) to (6) are related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period.

[0026] (1) The state of the rotation speed of the motor 50

[0027] (2) the state of the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC

[0028] (3) the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC

[0029] (4) the change in the control mode of the motor 50

[0030] (5) the relationship between an integer multiple of the frequency of the voltage of the power supply 60 and an integer multiple or M / N multiple of the rotational frequency of the motor 50

[0031] (6) the state of the voltage of the direct-current portion 22

[0032] By monitoring the above (1) to (6), it is possible to confirm whether or not the characteristic quantity has undergone an unintended change. Therefore, by releasing the restriction on the inference processing in accordance with the above (1) to (6), it is possible to appropriately release the restriction on the inference processing.

[0033] A ninth aspect of the present disclosure is the state inferring apparatus of any one of the first to eighth aspects of the present disclosure, wherein the physical quantity is any one of the current supplied to the motor 50, the voltage applied to the motor 50, the rotational speed of the motor 50, the vibration of the device 70, and the sound of the device 70.

[0034] A tenth aspect of the present disclosure is the state inferring apparatus of any one of the first to ninth aspects of the present disclosure, wherein the characteristic quantity is a frequency component.

[0035] In the tenth aspect, because the value of the frequency component is relatively small, the influence of an unintended change easily becomes large. Therefore, when the characteristic quantity is a frequency component, it is particularly effective to appropriately restrict the inference processing based on the characteristic quantity.

[0036] An eleventh aspect of the present disclosure is the state inferring apparatus of the third or fourth aspect of the present disclosure, wherein the inference restriction condition includes a condition in which the rotational speed of the motor 50 is a certain rotational speed and the pressure of the fluid flowing into the compressor CC and the pressure of the fluid flowing out of the compressor CC are certain pressures.

[0037] A twelfth aspect of the present disclosure relates to a drive system including a motor drive apparatus 20 that drives a motor 50 mounted on a device 70 and a state inferring apparatus that infers the state of the device 70, the state inferring apparatus being the state inferring apparatus of any one of the first to eleventh aspects.

[0038] The thirteenth aspect of the present disclosure relates to a refrigeration system including a refrigerant circuit RR1 including a compressor CC having a motor 50, and a state inferring apparatus, the state inferring apparatus being the state inferring apparatus of any one of the first to eleventh aspects, inferring a state of the refrigeration system.

[0039] The fourteenth aspect of the present disclosure relates to a fan system including a fan FF1, a motor 50 driving the fan FF1, and a state inferring apparatus, the state inferring apparatus being the state inferring apparatus of any one of the first, second, fifth to seventh aspects, inferring a state of the fan system.

[0040] The fifteenth aspect of the present disclosure relates to a state inferring method inferring a state of an apparatus 70 having a motor 50, the state inferring method including a calculating step in which a characteristic quantity is calculated from a physical quantity obtained from the apparatus 70 within a prescribed period, an inferring step in which the state of the apparatus 70 is inferred from the characteristic quantity calculated by the calculating step, and a restricting step in which the inferring step is restricted so as to output a preset inference result when a prescribed inference restricting condition is satisfied, the restriction on the inferring step is maintained until a prescribed standby release condition is satisfied when a prescribed restriction release condition is satisfied, and the restriction on the inferring step is released after the prescribed standby release condition is satisfied. The physical quantity is a quantity that varies in accordance with rotation of the motor 50. The characteristic quantity is a quantity that varies in accordance with the state of the apparatus 70. The state of the apparatus 70 includes at least one of an abnormality of the motor 50, a degree of deterioration of the motor 50, an abnormality of a component driven by the motor 50, and a degree of deterioration of the component driven by the motor 50. The inference restricting condition is a condition in which there is a possibility that a false inference occurs in the inferring step. The restriction release condition is a condition in which a false inference in the inferring step can be suppressed.

[0041] In the fifteenth aspect, when the prescribed inference restricting condition is satisfied, the inferring step is restricted so as to output a preset inference result, whereby a false inference of the state of the apparatus 70 can be appropriately suppressed. Further, by restricting the inferring step in accordance with satisfaction of the prescribed restriction release condition, the restriction on the inferring step can be appropriately released.

[0042] Further, in the fifteenth aspect, when the prescribed restriction release condition is satisfied, the restriction on the inference step is maintained until a prescribed standby release condition is satisfied, and the restriction on the inference step is released after the prescribed standby release condition is satisfied. In this way, compared to a case where the restriction on the inference step is released without waiting for the prescribed standby release condition to be satisfied, it is possible to release the restriction on the inference step after the characteristic quantity calculated in the calculation step has stabilized. In this way, it is possible to suppress erroneous inference of the state of the device 70 after the restriction on the inference step is released.

[0043] The sixteenth aspect of the present disclosure is based on the state inference method of the fifteenth aspect of the present disclosure, and the restriction release condition is a condition in which the rotational speed of the motor 50 changes from a non-stable state to a stable state.

[0044] In the sixteenth aspect, the state of the rotational speed of the motor 50 is related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 over a prescribed period. By monitoring the state of the rotational speed of the motor 50, it is possible to confirm whether or not the characteristic quantity has changed unexpectedly. Therefore, by releasing the restriction on the inference step in accordance with a change in the state of the rotational speed of the motor 50, it is possible to appropriately release the restriction on the inference step.

[0045] The seventeenth aspect of the present disclosure is based on the state inference method of the fifteenth aspect of the present disclosure, and the device 70 includes a compressor CC having the motor 50, and the restriction release condition is a condition in which the pressure of fluid flowing into the compressor CC or the pressure of fluid flowing out of the compressor CC changes from a non-stable state to a stable state.

[0046] In the seventeenth aspect, the state of the pressure of fluid flowing into the compressor CC or the pressure of fluid flowing out of the compressor CC is related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 over a prescribed period. By monitoring the state of the pressure of fluid flowing into the compressor CC or the pressure of fluid flowing out of the compressor CC, it is possible to confirm whether or not the characteristic quantity has changed unexpectedly. Therefore, by releasing the restriction on the inference step in accordance with a change in the state of the pressure of fluid flowing into the compressor CC or the pressure of fluid flowing out of the compressor CC, it is possible to appropriately release the restriction on the inference step.

[0047] The eighteenth aspect of the present disclosure is based on the state inference method of the fifteenth aspect of the present disclosure, and the device 70 includes a compressor CC having the motor 50, and the restriction release condition is a condition in which the temperature of fluid flowing into the compressor CC or the temperature of fluid flowing out of the compressor CC changes from a non-stable state to a stable state.

[0048] In the eighteenth aspect, the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC is related to the unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC, it is possible to confirm whether the characteristic quantity has undergone the unexpected change. Therefore, by releasing the restriction on the inference step in accordance with the change in the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC, it is possible to appropriately release the restriction on the inference step.

[0049] The nineteenth aspect of the present disclosure is based on the state inference method of the fifteenth aspect of the present disclosure, the release condition is the first condition or the second condition, the first condition is that the control mode of the motor 50 is changed after the inference step is restricted, and the second condition is that when the inference release condition is the condition that the control mode of the motor 50 is changed, the inference step is restricted in accordance with the change in the control mode of the motor 50.

[0050] In the nineteenth aspect, the change in the control mode of the motor 50 is related to the unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the change in the control mode of the motor 50, it is possible to confirm whether the characteristic quantity has undergone the unexpected change. Therefore, by releasing the restriction on the inference step in accordance with the change in the control mode of the motor 50, it is possible to appropriately release the restriction on the inference step.

[0051] The twentieth aspect of the present disclosure is based on the state inference method of the fifteenth aspect of the present disclosure, the motor 50 is driven by alternating current, the alternating current is generated based on the power supply power supplied from the power supply 60, and the release condition is the condition that the integer multiple or the M / N multiple (M, N are integers) of the rotational frequency of the motor 50 deviates from the vicinity of the integer multiple of the frequency of the voltage of the power supply 60.

[0052] In the twentieth aspect, the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50 is related to the unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50, it is possible to confirm whether the characteristic quantity has undergone the unexpected change. Therefore, by releasing the restriction on the inference step in accordance with the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50, it is possible to appropriately release the restriction on the inference step.

[0053] The twenty-first aspect of the present disclosure is based on the state inferring method of the fifteenth aspect of the present disclosure, the electric motor 50 is driven by the electric motor drive device 20, the electric motor drive device 20 has a direct current section 22 and a conversion section 23, the direct current section 22 generates direct current corresponding to the power supply power supplied from the power supply 60, the conversion section 23 converts the direct current generated by the direct current section 22 into alternating current through switching operation, and the restriction release condition is the condition that the voltage of the direct current section 22 changes from a non-stable state to a stable state.

[0054] In the twenty-first aspect, the state of the voltage of the direct current section 22 is related to the unexpected change of the characteristic quantity calculated according to the physical quantity obtained from the device 70 within a specified period. By monitoring the state of the voltage of the direct current section 22, it can be confirmed whether the characteristic quantity has an unexpected change. Therefore, by releasing the restriction on the inferring step according to the change of the voltage state of the direct current section 22, the restriction on the inferring step can be properly released.

[0055] The twenty-second aspect of the present disclosure is based on the state inferring method of the fifteenth aspect of the present disclosure, the device 70 includes a compressor CC having the motor 50, the restriction release condition includes at least two of a first release condition, a second release condition, a third release condition, a fourth release condition, a fifth release condition, and a sixth release condition, the first release condition is that the rotation speed of the motor 50 changes from a non-stable state to a stable state, the second release condition is that the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from a non-stable state to a stable state, the third release condition is that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from a non-stable state to a stable state, the fourth release condition is a first condition or a second condition, the first condition is that the control mode of the motor 50 changes after the inferring step is restricted, the second condition is that when the inferring restriction condition is the condition that the control mode of the motor 50 changes, the inferring step is restricted according to the change of the control mode of the motor 50, the fifth release condition is that when the motor 50 is driven by alternating current generated based on the power supply power supplied from the power supply 60, the rotation frequency of the motor 50 deviates from the vicinity of the integer multiple of the frequency of the voltage of the power supply 60, where M and N are integers, and the sixth release condition is that the motor drive device 20 has a direct current portion 22 that generates direct current corresponding to the power supply power supplied from the power supply 60 and a conversion portion 23 that converts the direct current generated by the direct current portion 22 into alternating current through switching operation, when the motor 50 is driven by the motor drive device 20, the voltage of the direct current portion 22 changes from a non-stable state to a stable state, and when all the conditions included in the restriction release condition are established, the restriction release condition is established.

[0056] In the twenty-second aspect, the following (1) to (6) are related to unexpected changes in the occurrence of characteristic quantities calculated from physical quantities obtained from the device 70 within a specified period.

[0057] (1) The state of the rotation speed of the motor 50

[0058] (2) The state of the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC

[0059] (3) The state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC

[0060] (4) The change in the control mode of the motor 50

[0061] (5) Relationship between an integer multiple of the frequency of the voltage of the power supply 60 and an integer multiple or M / N multiple of the rotational frequency of the motor 50

[0062] (6) State of the voltage of the DC portion 22

[0063] By monitoring the above (1) to (6), it is possible to confirm whether or not the characteristic quantity has undergone an unintended change. Therefore, by releasing the restriction on the inference step in accordance with the above (1) to (6), it is possible to appropriately release the restriction on the inference step.

[0064] A twenty-third aspect of the present disclosure relates to a state inference program that causes a computer to execute the state inference method of any one of the fifteenth to twenty-second aspects. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 is a circuit diagram showing a configuration example of the drive system of the first embodiment;

[0066] Figure 2 is a flowchart showing an example of the processing flow of the control portion;

[0067] Figure 3 is a waveform chart showing an example of the DC signal and the AC signal;

[0068] Figure 4 is a graph showing an example of the first frequency component included in the DC signal;

[0069] Figure 5 is a graph showing an example of the first frequency component included in the AC signal;

[0070] Figure 6 is a flowchart showing an example of the first inference processing;

[0071] Figure 7 is a flowchart showing an example of the second inference processing;

[0072] Figure 8 is a timing chart showing an example of the second inference processing;

[0073] Figure 9 is a flowchart showing an example of the third inference processing;

[0074] Figure 10 is a timing chart showing an example of the third inference processing;

[0075] Figure 11 is a flowchart showing an example of the fourth inference processing;

[0076] Figure 12 is a timing chart showing an example of the fourth inference processing;

[0077] Figure 13 is a diagram showing a configuration example of a drive system of the fifth embodiment;

[0078] Figure 14 is a diagram showing a configuration example of a refrigeration system;

[0079] Figure 15 is a diagram showing a configuration example of a fan system. DETAILED DESCRIPTION

[0080] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that the same or equivalent portions will be denoted by the same reference numerals, and repeated explanations will not be given.

[0081] (First Embodiment)

[0082] Figure 1 A configuration example of a drive system 10 of the first embodiment is shown. The drive system 10 drives a motor 50 using electric power supplied from a power supply 60. The motor 50 is installed in an apparatus 70. The motor 50 is, for example, an IPM motor (Interior Permanent Magnet Motor). In this example, the power supply 60 is an alternating current power supply, and the motor 50 is a three-phase alternating current motor. The drive system 10 is installed in the apparatus 70. For example, the apparatus 70 is an outdoor unit of an air conditioner. The drive system 10 includes a motor drive device 20 and a control device 30.

[0083] 〔Motor Drive Device〕

[0084] The motor drive device 20 drives the motor 50. Specifically, the motor drive device 20 converts electric power supplied from the power supply 60 into output alternating current having a prescribed frequency and voltage (in this example, three-phase alternating current), and supplies the output alternating current to the motor 50. In this example, the motor drive device 20 has an AC / DC converter 21, a DC portion 22, and a DC / AC converter 23.

[0085] The AC / DC converter 21 rectifies electric power supplied from the power supply 60. In this example, the AC / DC converter 21 performs full-wave rectification on alternating current supplied from the power supply 60. For example, the AC / DC converter 21 is configured by a diode bridge circuit that is configured by bridge-connection of a plurality of rectifier diodes.

[0086] The DC portion 22 generates direct current corresponding to the electric power supplied from the power supply 60. In this example, the DC portion 22 has a capacitor, and performs smoothing processing on the output of the AC / DC converter 21.

[0087] The DC-AC converter 23 has multiple switching elements, and uses the switching operation of the multiple switching elements to convert the output of the DC unit 22 into AC power (three-phase AC power) with a specified frequency and voltage. The DC-AC converter 23 is an example of a conversion unit that uses switching operation to convert the DC power generated by the DC unit 22 into AC power.

[0088] In this example, the DC-AC converter 23 has six switching elements connected in a bridge configuration and six freewheeling diodes connected in reverse parallel with each of the six switching elements. Specifically, the DC-AC converter 23 has three switching arms, each consisting of two switching elements connected in series. The midpoints of these three switching arms (specifically, the connection points between the upper and lower switching elements) are connected to the three windings of the motor 50 (the U-phase, V-phase, and W-phase windings), respectively.

[0089] [Various sensors]

[0090] The motor drive unit 20 is equipped with various sensors, such as a phase current detection unit 41 and an electrical angle frequency detection unit 42. Various information detected by these sensors is sent to the control unit 30. Specifically, the detection signals from the various sensors are sent to the control unit 31, which will be described later.

[0091] The phase current detection unit 41 detects the three-phase currents (U-phase current iu, V-phase current iv, and W-phase current iw) flowing in the three windings (not shown) of the motor 50. For example, the phase current detection unit 41 can detect all three-phase currents iu, iv, and iw, or it can detect two of the three-phase currents iu, iv, and iw and derive the remaining phase current based on the detected two-phase currents. Furthermore, the phase current detection unit 41 can also derive the three-phase currents iu, iv, and iw based on the DC current detected by the shunt resistor (not shown) provided in the DC section 22 and the switching mode.

[0092] The electrical angle frequency detection unit 42 is configured to detect the electrical angle frequency ω of the motor 50. It should be noted that the electrical angle frequency detection unit 42 is not a necessary component, and the electrical angle frequency ω of the motor 50 can also be calculated by other methods or inferred using a sensorless method.

[0093] [Control device (state inference device)]

[0094] Control device 30 infers the state of device 70. Control device 30 is an example of a state inference device for inferring the state of device 70 on which motor 50 is installed. The processing in control device 30 (processing related to the inference of the state of device 70) is an example of a state inference method for inferring the state of device 70 on which motor 50 is installed.

[0095] In this example, the control device 30 infers whether the device 70 has an abnormality, and copes with the abnormality of the device 70. In addition, the control device 30 controls the motor 50. Specifically, the control device 30 controls the motor 50 by controlling the motor drive device 20.

[0096] 〔Control section〕

[0097] The control device 30 includes a control section 31. The control section 31 performs various processes. Specifically, the control section 31 acquires information and data from each part of the device 70, and performs various processes based on the information and data. The processes performed by the control section 31 will be described later in detail.

[0098] For example, the control section 31 includes a processor and a memory electrically connected to the processor, which stores a program for causing the processor to operate. The various functions of the control section 31 are realized by the program being executed by the processor. Note that the control section 31 is an example of a computer, and the program is an example of a state inference program.

[0099] 〔Processes performed by control section〕

[0100] In this example, the control section 31 performs a calculation process, an inference process, a restriction process, a control process, and a coping process. Note that the various processes are examples of various steps. For example, the calculation process is an example of a calculation step, the inference process is an example of an inference step, and the restriction process is an example of a restriction step.

[0101] 〔Calculation process〕

[0102] In the calculation process, the control section 31 calculates a characteristic quantity based on a physical quantity obtained from the device 70 within a prescribed period. In this example, the control section 31 derives a first frequency component based on a signal of a current or a voltage of the motor 50. The signal of the current or the voltage of the motor 50 is an example of a physical quantity obtained from the device 70. The first frequency component is an example of a characteristic quantity. Note that specific examples of the signal and the first frequency component will be described later in detail.

[0103] 〔Inference process〕

[0104] In the inference process, the control section 31 infers a state of the device 70 based on the characteristic quantity calculated by the calculation process. Also, the control section 31 outputs the inference result. In this example, the control section 31 infers whether the device 70 has an abnormality in the inference process. In addition, the control section 31 infers a state of the device 70 based on the first frequency component based on the signal of the current or the voltage of the motor 50 in the inference process. Note that specific examples of the inference process will be described later in detail.

[0105] 〔Restriction process〕

[0106] In the restriction processing, when the prescribed inference restriction condition is established, the control section 31 restricts the inference processing so as to output the preset inference result, and when the prescribed restriction release condition is established, the control section 31 releases the restriction on the inference processing after the prescribed standby release condition is established. Note that a specific example of the processing for restricting the inference processing will be described later in detail.

[0107] In this example (example in which the inference processing infers whether the device 70 has an abnormality), the preset inference result is not an inference result indicating that the device 70 is abnormal. The preset inference result is, for example, an inference result indicating that the device 70 is normal, an inference result indicating that the state of the device 70 is unknown, an inference result indicating that the inference processing is prohibited (stopped), an inference result output before the inference processing is restricted (for example, immediately before being restricted), or the like.

[0108] Flow of processing by control section

[0109] Next, the flow of the processing (specifically, the calculation processing, the inference processing, and the restriction processing) performed by the control section 31 will be described with reference to the flowchart shown in FIG. 6. Figure 2

[0110] The control section 31 performs the calculation processing at each prescribed calculation time. By repeatedly performing the calculation processing, the characteristic quantity is calculated at each calculation time.

[0111] Further, the control section 31 performs the inference processing at each prescribed inference time on the basis of the characteristic quantity calculated by the calculation processing. By repeatedly performing the inference processing, the inference result is obtained at each inference time.

[0112] In addition, the control section 31 performs the restriction processing in parallel with the calculation processing and the inference processing. Specifically, the control section 31 repeatedly performs the processing of steps S101 to S105 shown in FIG. 6. Figure 2

[0113] <Step S101>

[0114] The control section 31 determines whether the inference restriction condition is established. When the inference restriction condition is established, the processing of step S102 is performed. For example, the processing of step S101 is performed at each prescribed determination time. In other words, the processing of step S101 is repeatedly performed until the inference restriction condition is established.

[0115] <Step S102>

[0116] When the inference restriction condition is established, the control section 31 restricts the inference processing so as to output the preset inference result.

[0117] <Step S103> ​​

[0118] Next, the control section 31 determines whether or not the restriction release condition is satisfied. When the restriction release condition is satisfied, the process of step S104 is performed. For example, the process of step S103 is performed every prescribed determination time. In other words, the process of step S103 is repeatedly performed until the restriction release condition is satisfied.

[0119] <Step S104>

[0120] Next, the control section 31 determines whether or not the standby release condition is satisfied. When the standby release condition is satisfied, the process of step S105 is performed. For example, the process of step S104 is performed every prescribed determination time. In other words, the process of step S104 is repeatedly performed until the standby release condition is satisfied.

[0121] <Step S105>

[0122] After the restriction release condition is satisfied, if the standby release condition is satisfied, the control section 31 releases the restriction on the inference process.

[0123] [Control Process]

[0124] In the control process, the control section 31 controls the motor driving device 20 to control the motor 50. Specifically, the control section 31 inputs a target command value such as a command value of an electric angle frequency ω of the motor 50, a detection signal of various sensors provided in the motor driving device 20, and the like. Then, the control section 31 controls the switching operation of the AC / DC converter 23 to control the AC power supplied from the AC / DC converter 23 to the motor 50, on the basis of the target command value and the detection signal of the various sensors, and the like.

[0125] [Response Process]

[0126] In this example, when the control section 31 infers that the state of the device 70 is the abnormal state in the inference process, the control section 31 performs a response process. The response process is a process for responding to the abnormality of the device 70, and includes at least one of an output process in which first information indicating that the state of the device 70 is the abnormal state is output, and a change process in which an operation condition of the motor 50 is changed.

[0127] The output process is, for example, a first output process, a second output process, a third output process, a combination of the above processes, or the like. The first output process is a process of causing a display device (omitted from the drawing) provided on a remote controller or the like to display the first information by outputting the first information to the display device. The second output process is a process of causing a control section (omitted from the drawing) that controls the operation of the device 70 to perform a process for responding to the operation of the device 70 by outputting the first information to the control section. The third output process is a process of uploading the first information to a data accumulation section (omitted from the drawing) on the cloud.

[0128] The change processing is, for example, first change processing, second change processing, third change processing, and a combination of the above processing, and the like. The first change processing is processing that stops the motor 50. The second change processing is processing that accelerates the motor 50. The third change processing is processing that decelerates the motor 50.

[0129] 〔Inference restriction condition and restriction release condition〕

[0130] The inference restriction condition of the first embodiment is a condition in which the rotation speed of the motor 50 changes from the stable state to the unstable state. The restriction release condition of the first embodiment is a condition in which the rotation speed of the motor 50 changes from the unstable state to the stable state. In the restriction processing of the first embodiment, when the rotation speed of the motor 50 changes from the stable state to the unstable state, the control section 31 restricts the inference processing so as to output a preset inference result, and when the rotation speed of the motor 50 changes from the unstable state to the stable state, the control section 31 releases the restriction on the inference processing after a prescribed standby release condition is satisfied.

[0131] Note that the rotation speed of the motor 50 can be detected by a rotation speed detection section (not shown) provided in the drive system 10, for example. The rotation speed of the motor 50 detected by the rotation speed detection section is transmitted to the control section 31.

[0132] Further, the stable state of the rotation speed of the motor 50 is, for example, a state in which the difference between the rotation speed command value and the rotation speed measured value is within a prescribed difference. For example, the prescribed difference is 0.1 rps. The unstable state of the rotation speed of the motor 50 is a state in which the difference between the rotation speed command value and the rotation speed measured value is greater than the prescribed difference.

[0133] Alternatively, the stable state of the rotation speed of the motor 50 can be a state in which the difference between the present value and the previous value of the rotation speed measured value is within a prescribed difference. For example, the previous value is a rotation speed measured value obtained one second before the present value, and the prescribed difference is 0.1 rps. The unstable state of the rotation speed of the motor 50 can be a state in which the difference between the present value and the previous value of the rotation speed measured value is greater than the prescribed difference.

[0134] Note that the rotation speed command value can be used instead of the above-described rotation speed measured value. For example, the stable state of the rotation speed of the motor 50 can be a state in which the difference between the present value and the previous value of the rotation speed command value is within a prescribed difference.

[0135] Alternatively, the steady state of the rotation speed of the motor 50 can also be a state in which neither the acceleration flag nor the deceleration flag of the rotation speed held in the control section 31 is set. The control section 31 can set the acceleration flag of the rotation speed held in the control section 31 when the rotation speed of the motor 50 is increased, and otherwise reset the acceleration flag. Further, the control section 31 can set the deceleration flag of the rotation speed held in the control section 31 when the rotation speed of the motor 50 is decreased, and otherwise reset the deceleration flag. The non-steady state of the rotation speed of the motor 50 can also be a state in which one of the acceleration flag and the deceleration flag of the rotation speed held in the control section 31 is set.

[0136] [Effects of the First Embodiment]

[0137] As described above, in the first embodiment, in the restriction processing, when the prescribed inference restriction condition is established, the control section 31 restricts the inference processing so as to output the preset inference result, and when the prescribed restriction release condition is established, the control section 31 releases the restriction on the inference processing after the prescribed standby release condition is established.

[0138] In the above-described configuration, when the inference restriction condition (for example, a condition in which the characteristic quantity undergoes an unexpected change) is established, the inference processing is restricted so as to output the preset inference result, whereby it is possible to suppress false inference of the state of the device 70. In this example, because it is possible to restrict the inference processing so as not to output the inference result indicating the abnormality of the device 70, it is possible to prevent false inference of the abnormality of the device 70.

[0139] Further, in the first embodiment, the inference restriction condition is a condition in which the rotation speed of the motor 50 changes from the steady state to the non-steady state. The restriction release condition is a condition in which the rotation speed of the motor 50 changes from the non-steady state to the steady state.

[0140] In the first embodiment, the state of the rotation speed of the motor 50 is related to the tendency of the characteristic quantity to undergo an unexpected change, which is calculated from the physical quantity obtained from the device 70 within a prescribed period. For example, when the rotation speed of the motor 50 is in the steady state, the characteristic quantity has a tendency to be difficult to undergo an unexpected change, and when the rotation speed of the motor 50 is in the non-steady state, the characteristic quantity has a tendency to be easy to undergo an unexpected change. By monitoring the state of the rotation speed of the motor 50, it is possible to confirm whether the characteristic quantity undergoes an unexpected change. Therefore, by performing the restriction and the release of the restriction on the inference processing in accordance with the change in the state of the rotation speed of the motor 50, it is possible to appropriately perform the restriction and the release of the restriction on the inference processing.

[0141] Further, in the first embodiment, the characteristic quantity is the frequency component. Since the value of the frequency component is relatively small, the influence of the unexpected fluctuation easily becomes large. Therefore, when the characteristic quantity is the frequency component, it is particularly effective to appropriately limit the inference processing based on the characteristic quantity.

[0142] Note that, immediately after the prescribed limitation release condition is established, the influence of the unexpected fluctuation can remain in the characteristic quantity (particularly, the frequency component) calculated from the physical quantity obtained from the device 70 within the prescribed period. Therefore, if the limitation on the inference processing is released without waiting for the standby release condition to be established after the limitation release condition is established, the state of the device 70 can be erroneously inferred in the inference processing after the limitation release.

[0143] Therefore, in the first embodiment, in the limitation processing, when the prescribed limitation release condition is established, the control section 31 releases the limitation on the inference processing after the prescribed standby release condition is established. According to the above-described configuration, compared with the case where the limitation on the inference processing is released without waiting for the standby release condition to be established after the limitation release condition is established, the limitation on the inference processing can be released after the characteristic quantity calculated by the calculation processing is stabilized. In this way, it is possible to suppress the erroneous inference of the state of the device 70 after the limitation on the inference processing is released.

[0144] (Comparison between the embodiment and the comparative example)

[0145] Note that, the inference limitation condition includes, for example, a condition that the state of the power supply 60 changes from normal to abnormal (comparative example). Further, the limitation release condition includes, for example, a condition that the state of the power supply 60 changes from abnormal to normal (comparative example). However, the characteristic quantity calculated from the physical quantity obtained from the device 70 within the prescribed period can fluctuate unexpectedly due to a cause other than the power supply 60. Therefore, the limitation and the limitation release on the inference processing based only on the state of the power supply 60 cannot sufficiently suppress the erroneous inference of the state of the device 70.

[0146] (Specific examples of signals)

[0147] Hereinafter, specific examples of the "signal based on the current or voltage of the motor 50" will be described. The signal is roughly classified into a direct current signal and an alternating current signal. Figure 3 Examples of the direct current signal and the alternating current signal will be described. In Figure 3 , an example of the direct current signal, i.e., "square root of the sum of the squares of the respective phase currents iu, iv, and iw of the motor 50", and an example of the alternating current signal, i.e., "the respective phase currents iu, iv, and iw of the motor 50" are shown.

[0148] (Specific examples of direct current signals)

[0149] The DC signals include, for example, "signals related to the phase currents iu, iv, iw of the motor 50," "signals related to the phase voltages Vu, Vv, Vw of the motor 50," and "signals related to the power of the motor 50."

[0150] Another example of the DC signals includes, for example, "the currents iγ, iδ obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 using the phase ωi•t of the phase currents iu, iv, iw of the motor 50," "the voltages Vγ, Vδ obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 50 using the phase ωv•t of the phase voltages Vu, Vv, Vw of the motor 50," "the currents iζ, iη obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 using the phase ωv•t of the phase voltages Vu, Vv, Vw of the motor 50," and "the voltages Vζ, Vη obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 50 using the phase ωi•t of the phase currents iu, iv, iw of the motor 50."

[0151] Still another example of the DC signals includes, for example, "the dq-axis fluxes λd, λq obtained by coordinate-converting the armature flux generated by the permanent magnet," and "the magnitude λ0 of the armature flux vector obtained by combining the armature flux of the permanent magnet and the armature reaction."

[0152] Note that, in the following description, the "phase currents iu, iv, iw of the motor 50" are the phase currents iu, iv, iw of the motor 50 detected by the phase current detector 41. The "phase voltages Vu, Vv, Vw of the motor 50" are the phase voltages Vu, Vv, Vw of the motor 50 indicated by the voltage command value used in the inside of the control section 31 or the phase voltages Vu, Vv, Vw of the motor 50 detected by the phase voltage detector (not shown) provided in the motor drive device 20. The "electric angle frequency ω of the motor 50" is the electric angle frequency ω of the motor 50 detected by the electric angle frequency detector 42.

[0153] 〔1. Specific examples of signals related to the phase currents of the motor〕

[0154] Specific examples of the signals related to the phase currents iu, iv, iw of the motor 50 include, for example, the current vector amplitude Ia, the square value Ia 2 of the current vector amplitude, the phase current amplitude I, the phase current effective value Irms, and the like.

[0155] Note that, the current vector amplitude Ia and the square value Ia 2is 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 50. 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 50 is an example of a value proportional to an integral power of the magnitude of the phase currents iu, iv, iw of the motor 50.

[0156] (1) Current vector amplitude

[0157] The current vector amplitude Ia is derived from the phase currents iu, iv, iw of the motor 50. In addition, the current vector amplitude Ia can also be derived from the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 50 to a fixed coordinate system. In addition, the current vector amplitude Ia can also be derived from the M-axis current iM and the T-axis current iT, both of which are obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on an angle obtained based on the direction of the primary magnetic flux. In addition, the current vector amplitude Ia can also be derived from the d-axis current id and the q-axis current iq, both of which are obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on an angle obtained based on the direction of the magnetic pole position. Specifically, the current vector amplitude Ia can be expressed by the following equation.

[0158] [Equation 1]

[0159]

[0160] (2) Square value of current vector amplitude

[0161] The square value of the current vector amplitude Ia 2 is derived from the phase currents iu, iv, iw of the motor 50. In addition, the square value of the current vector amplitude Ia 2 can also be derived from the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 50 to a fixed coordinate system. In addition, the square value of the current vector amplitude Ia 2 can also be derived from the M-axis current iM and the T-axis current iT, both of which are obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on an angle obtained based on the direction of the primary magnetic flux. In addition, the square value of the current vector amplitude Ia 2 can also be derived from the d-axis current id and the q-axis current iq, both of which are obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on an angle obtained based on the direction of the magnetic pole position. Specifically, the square value of the current vector amplitude Ia 2 can be expressed by the following equation.

[0162] [Math. 2]

[0163]

[0164] (3) Phase current amplitude

[0165] The phase current amplitude I is derived from one of the phase currents (e.g., the U-phase current iu) of the motor 50 and the phase of the phase current ωi. Note that the phase of the phase current ωi is derived from the phase currents iu, iv, iw of the motor 50, for example. Specifically, the phase current amplitude I can be expressed by the following equation.

[0166] [Math. 3]

[0167]

[0168] (4) Phase current effective value

[0169] The phase current effective value Irms is derived from the phase current amplitude I. Specifically, the phase current effective value Irms can be expressed by the following equation.

[0170] [Math. 4]

[0171]

[0172] (5) Others

[0173] In the above description, the case where the current vector amplitude Ia is derived from the phase currents iu, iv, iw of the three phases of the motor 50 is exemplified, but the current vector amplitude Ia can also be derived from the phase currents of two of the three phases of the motor 50. Further, the current vector amplitude Ia can also be derived from the direct current of the direct-current inverter 23 detected by a direct-current detection section (e.g., a shunt resistor, not shown) provided in the motor drive device 20. The square value Ia 2 of the current vector amplitude is also the same.

[0174] 〔2. Specific examples of signals related to phase voltage of motor〕

[0175] Specific examples of signals related to the phase voltages Vu, Vv, Vw of the motor 50 include the voltage vector amplitude Va, the square value Va 2 of the voltage vector amplitude, the phase voltage amplitude V, the phase voltage effective value Vrms, and the like.

[0176] Note that the voltage vector amplitude Vaand the square value Va 2is an example of a value corresponding to the sum of the squared values of the respective phase voltages Vu, Vv, and Vw of the three phases of the motor 50. The value corresponding to the sum of the squared values of the respective phase voltages Vu, Vv, and Vw of the three phases of the motor 50 is an example of a value proportional to an integral power of the magnitude of the phase voltages Vu, Vv, and Vw of the motor 50.

[0177] (1) Voltage vector amplitude

[0178] The voltage vector amplitude Va is derived from the phase voltages Vu, Vv, and Vw of the motor 50. Further, the voltage vector amplitude Va can also be derived from the α-phase voltage Vα and the β-phase voltage Vβ obtained by converting the phase voltages Vu, Vv, and Vw of the motor 50 to a fixed coordinate system. Further, the voltage vector amplitude Va can also be derived from the M-axis voltage VM and the T-axis voltage VT, both of which are obtained by coordinate-converting the phase voltages Vu, Vv, and Vw of the motor 50 based on an angle obtained based on the direction of the primary magnetic flux. Further, the voltage vector amplitude Va can also be derived from the d-axis voltage Vd and the q-axis voltage Vq, both of which are obtained by coordinate-converting the phase voltages Vu, Vv, and Vw of the motor 50 based on an angle obtained based on the direction of the magnetic pole position. Specifically, the voltage vector amplitude Va can be expressed by the following equation.

[0179] [Equation 5]

[0180]

[0181] (2) Squared value of voltage vector amplitude

[0182] The squared value of the voltage vector amplitude Va 2 is derived from the phase voltages Vu, Vv, and Vw of the motor 50. Further, the squared value of the voltage vector amplitude Va 2 can also be derived from the α-phase voltage Vα and the β-phase voltage Vβ obtained by converting the phase voltages Vu, Vv, and Vw of the motor 50 to a fixed coordinate system. Further, the squared value of the voltage vector amplitude Va 2 can also be derived from the M-axis voltage VM and the T-axis voltage VT, both of which are obtained by coordinate-converting the phase voltages Vu, Vv, and Vw of the motor 50 based on an angle obtained based on the direction of the primary magnetic flux. Further, the squared value of the voltage vector amplitude Va 2 can also be derived from the d-axis voltage Vd and the q-axis voltage Vq, both of which are obtained by coordinate-converting the phase voltages Vu, Vv, and Vw of the motor 50 based on an angle obtained based on the direction of the magnetic pole position. Specifically, the squared value of the voltage vector amplitude Va 2 can be expressed by the following equation.

[0183] [Math. 6]

[0184]

[0185] (3) Phase voltage amplitude

[0186] The phase voltage amplitude V is derived from one of the phase voltages (e.g., the U-phase voltage Vu) of the motor 50 and the phase ωv of the phase voltage. Note that the phase ωv of the phase voltage is derived from the phase voltages Vu, Vv, Vw of the motor 50, for example. Specifically, the phase voltage amplitude V can be expressed by the following equation.

[0187] [Math. 7]

[0188]

[0189] (4) Phase voltage effective value

[0190] The phase voltage effective value Vrms is derived from the phase voltage amplitude V. Specifically, the phase voltage effective value Vrms can be expressed by the following equation.

[0191] [Math. 8]

[0192]

[0193] (5) Others

[0194] In the above description, the case where the voltage vector amplitude Va is derived from the three-phase phase voltages Vu, Vv, Vw of the motor 50 is exemplified, but the voltage vector amplitude Va can also be derived from the phase voltages of two of the three-phase phase voltages Vu, Vv, Vw of the motor 50. The square value Va2 of the voltage vector amplitude can be expressed by the following equation. 2 The same applies.

[0195] 〔3. Specific examples of signals related to the power of the motor〕

[0196] The signals related to the power of the motor 50 include, for example, the instantaneous power p, the instantaneous reactive power q, the apparent power S, the active power P, the reactive power Q, and the like.

[0197] (1) Instantaneous power

[0198] The instantaneous power p is derived from the phase currents iu, iv, iw of the motor 50 and the phase voltages Vu, Vv, Vw of the motor 50. In addition, the instantaneous power p can also be derived from the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 50 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 50 to a fixed coordinate system. In addition, the instantaneous power p can also be derived from the M-axis current iM and the T-axis current iT, which are both obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on the direction of the primary magnetic flux at an angle obtained based on the direction of the primary magnetic flux, and the M-axis voltage VM and the T-axis voltage VT, which are both obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 50 based on the direction of the primary magnetic flux at an angle obtained based on the direction of the primary magnetic flux. In addition, the instantaneous power p can also be derived from the d-axis current id and the q-axis current iq, which are both obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on the direction of the magnetic pole position at an angle obtained based on the direction of the magnetic pole position, and the d-axis voltage Vd and the q-axis voltage Vq, which are both obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 50 based on the direction of the magnetic pole position at an angle obtained based on the direction of the magnetic pole position. Specifically, the instantaneous power p can be expressed by the following equations.

[0199] [Math. 9]

[0200] p = v u i u + v v i v + v w i w = v α i α + v β i β = v M i M + v T i T = v d i d + v q i q

[0201] (2) Instantaneous reactive power

[0202] The instantaneous reactive power q is derived from the α-phase current iα and the β-phase current iβ obtained by converting the phase currents iu, iv, iw of the motor 50 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 50 to the fixed coordinate system. Further, the instantaneous reactive power q can also be derived from the M-axis current iM and the T-axis current iT, which are both obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on the direction of the primary magnetic flux at an angle obtained based on the direction of the primary magnetic flux, and the M-axis voltage VM and the T-axis voltage VT, which are both obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 50 based on the direction of the primary magnetic flux at an angle obtained based on the direction of the primary magnetic flux. Further, the instantaneous reactive power q can also be derived from the d-axis current id and the q-axis current iq, which are both obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 based on the direction of the magnetic pole position at an angle obtained based on the direction of the magnetic pole position, and the d-axis voltage Vd and the q-axis voltage Vq, which are both obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 50 based on the direction of the magnetic pole position at an angle obtained based on the direction of the magnetic pole position. Specifically, the instantaneous reactive power q can be expressed by the following equation.

[0203] [Math. 10]

[0204] q = v α i β -v β i α = v M i T -v T i M = v d i q -v q i d

[0205] (3) Apparent Power

[0206] The apparent power S is derived from the phase voltage effective value Vrms and the phase current effective value Irms. Specifically, the apparent power S can be expressed by the following equation.

[0207] [Math. 11]

[0208] S = 3V rms I rms

[0209] (4) Active Power

[0210] The active power P is derived from 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 φ1 of the phase voltage and the phase current, which is the phase difference of one phase voltage (for example, U-phase voltage Vu) and one phase current (for example, U-phase current iu), is derived from the phase ωi of the phase current and the phase ωv of the phase voltage. Specifically, the active power P can be expressed by the following equation.

[0211] [Math. 12]

[0212]

[0213] (5) Reactive power

[0214] The reactive power Q is derived from 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 φ1 of the phase voltage and the phase current, which is the phase difference of the U-phase voltage Vu and the U-phase current iu, for example, is derived from the phase ωi of the phase current and the phase ωv of the phase voltage. Specifically, the reactive power Q can be expressed by the following equation.

[0215] [Math. 13]

[0216]

[0217] 〔4. Current obtained by coordinate conversion of phase current using phase of phase current〕

[0218] The currents iγ, iδ obtained by coordinate conversion of the phase currents iu, iv, iw of the motor 50 using the phases ωi•t of the phase currents iu, iv, iw of the motor 50 can be expressed by the following equation.

[0219] [Math. 14]

[0220]

[0221] 〔5. Voltage obtained by coordinate conversion of phase voltage using phase of phase voltage〕

[0222] The voltages Vγ, Vδ obtained by coordinate conversion of the phase voltages Vu, Vv, Vw of the motor 50 using the phases ωv•t of the phase voltages Vu, Vv, Vw of the motor 50 can be expressed by the following equation.

[0223] [Math. 15]

[0224]

[0225] 〔6. Current obtained by coordinate conversion of phase current using phase of phase voltage〕

[0226] The currents iζ, iη obtained by coordinate-converting the phase currents iu, iv, iw of the motor 50 with the phase ωv-t of the phase voltages Vu, Vv, Vw of the motor 50 can be expressed by the following equations.

[0227] [Equation 16]

[0228]

[0229] 〔7. Voltage obtained by coordinate-converting phase voltage with phase of phase current〕

[0230] The voltages Vζ, Vη obtained by coordinate-converting the phase voltages Vu, Vv, Vw of the motor 50 with the phase ωi-t of the phase currents iu, iv, iw of the motor 50 can be expressed by the following equations.

[0231] [Equation 17]

[0232]

[0233] 〔6. Magnitude of dq-axis flux and armature cross flux vector〕

[0234] The dq-axis fluxes λd, λq obtained by coordinate-converting the armature cross flux generated by the permanent magnet and the magnitude λ0 of the armature cross flux vector obtained by combining the armature cross flux of the permanent magnet and the armature reaction can be expressed by the following equations. "Ld" in the following equations is the d-axis inductance, and "Lq" is the q-axis inductance.

[0235] [Equation 18]

[0236]

[0237] 〔7. Another example of DC signal〕

[0238] Further, the DC signal can also be a DC signal obtained by three-phase to two-phase converting the phase currents, the phase voltages, the line currents, and the line-to-line voltages of the motor 50, and further performing rotational coordinate conversion. For example, the DC signal can also be a d-axis current and a q-axis current obtained by performing three-phase to two-phase conversion on the phase currents of the motor 50 to obtain α-axis currents and β-axis currents, and performing rotational coordinate conversion on the α-axis currents and the β-axis currents at an angle obtained based on the direction of the magnetic pole of the rotor of the motor 50. Further, the DC signal can also be an M-axis current and a T-axis current obtained by performing rotational coordinate conversion on the α-axis currents and the β-axis currents at an angle obtained based on the direction of the primary flux of the rotor of the motor 50.

[0239] Further, the DC signal can be a power input to the AC / DC converter 21 of the motor drive device 20, a power output from the AC / DC converter 21, a power output from the DC portion 22, a current flowing between the AC / DC converter 21 and the DC portion 22, a current flowing between the DC portion 22 and the AC / DC converter 23, and the like.

[0240] (Specific examples of AC signals)

[0241] The AC signals are, for example, "phase currents iu, iv, iw of the motor 50", "phase voltages Vu, Vv, Vw of the motor 50", and "interlinking magnetic fluxes Ψfu, Ψfv, Ψfw of the respective phases".

[0242] The interlinking magnetic fluxes Ψfu, Ψfv, Ψfw of the respective phases can be expressed by the following equations.

[0243] [Equation 19]

[0244]

[0245] Another example of the AC signal is, for example, a current, a voltage, and an interlinking magnetic flux in a fixed coordinate obtained by performing three-phase / two-phase conversion on the above-described AC signals.

[0246] Further, the AC signal can be a line current, a line-to-line voltage, and the like of the motor 50. Further, the AC signal can be a two-phase AC current (for example, an α-axis current and a β-axis current) and a two-phase AC voltage obtained by performing three-phase / two-phase conversion on the phase currents, the phase voltages, the line current, and the line-to-line voltage. Further, the AC current can be a current flowing between a commercial power system (specifically, the AC power supply 60) and the AC / DC converter 21 of the motor drive device 20.

[0247] (Specific examples of first frequency components)

[0248] Hereinafter, the first frequency component C1 of a signal based on a current or a voltage of the motor 50 will be described with reference to Figure 4 and Figure 5

[0249] As shown in Figure 4 , when the above-described signal is a DC signal, the frequency of the first frequency component C1 is the frequency of the specific frequency component Cs.

[0250] The specific frequency component Cs is a frequency component that is less than one time the mechanical angular frequency fm of the motor 50. The frequency of the specific frequency component Cs is a frequency obtained by multiplying the mechanical angular frequency fm of the motor 50 by a specific ratio. The specific ratio is a fractional ratio expressed by a reciprocal of a natural number. For example, the specific ratio is 1 / 3 or 2 / 3. Note that the mechanical angular frequency fm of the motor 50 corresponds to the rotational frequency of the motor 50. ​

[0251] In Figure 4 the example, the frequency of the specific frequency component Cs is a frequency "1 / 3fm" obtained by multiplying the mechanical angular frequency fm of the motor 50 by "1 / 3" or a frequency "2 / 3fm" obtained by multiplying the mechanical angular frequency fm of the motor 50 by "2 / 3". The frequency of the first frequency component Cl is "1 / 3fm" or "2 / 3fm".

[0252] As Figure 5 shown in the drawing, when the above-mentioned signal is an alternating-current signal, the frequency of the first frequency component Cl is a frequency (first frequency) obtained by subtracting the frequency of the specific frequency component Cs from the fundamental frequency fo of the above-mentioned signal or a frequency (second frequency) obtained by adding the frequency of the specific frequency component Cs to the fundamental frequency fo of the above-mentioned signal.

[0253] In Figure 5 the example, the frequency of the specific frequency component Cs is a frequency "1 / 3fm" obtained by multiplying the mechanical angular frequency fm of the motor 50 by "1 / 3". The first frequency is "f0-1 / 3fm", and the second frequency is "f0+1 / 3fm". The frequency of the first frequency component Cl is "f0-1 / 3fm" or "f0+1 / 3fm".

[0254] By setting the first frequency component Cl as described above, it is possible to infer whether or not a specific state (an example of an abnormal state) is present, the specific state being a state in which the amplitude variation of the specific frequency component Cs whose frequency is one time the mechanical angular frequency fm of the motor 50 is insufficient for the torque generation of the motor 50. In other words, in this example, the first frequency component Cl is a frequency component that generates amplitude variation corresponding to the amplitude variation of the torque generation of the motor 50 (amplitude variation of the specific frequency component Cs) in the case where the state of the device 70 is the above-mentioned specific state.

[0255] Note that the above-mentioned specific state is a state in which the rotating shaft or the bearing of the rotating shaft that is rotated by the motor 50 has been worn. In other words, the above-mentioned specific state is a state in which the amount of wear of the rotating shaft or the bearing exceeds an allowable amount.

[0256] When the above-mentioned wear occurs in the rotating shaft or the bearing, the torque of the motor 50 generates amplitude variation of the specific frequency component Cs whose frequency is one time (specifically, 1 / 3 or 2 / 3) the mechanical angular frequency fm of the motor 50, as a result of which the first frequency component Cl of the signal based on the current or voltage of the motor 50 appears to vary (for example, amplitude variation).

[0257] (Detailed example of inference processing)

[0258] The following describes specific examples of the inference processing. The inference processing is, for example, the following four kinds of inference processing (first to fourth inference processing). Note that the following describes a case where the inference processing is performed based on the amplitude of the first frequency component. The "first frequency component" in the following description is the "amplitude of the first frequency component".

[0259] 〔First Inference Processing〕

[0260] First, with reference to Figure 6 , the first inference processing is described. In the first inference processing, the control section 31 infers whether the state of the device 70 is an abnormal state based on the first frequency component (specifically, the amplitude value of the first frequency component). Specifically, the control section 31 performs the following processing (steps S11 to S13) at each of the preset detection periods.

[0261] 〈Step S11〉

[0262] The control section 31 acquires the first frequency component.

[0263] 〈Step S12〉

[0264] Next, the control section 31 determines whether the first frequency component acquired in step S11 is equal to or greater than a preset upper limit value. Note that the upper limit value is an example of a threshold value used in the inference processing. When the first frequency component is equal to or greater than the upper limit value, the processing of step S13 is performed. Otherwise, the processing of step S14 is performed.

[0265] 〈Step S13〉

[0266] When the first frequency component is equal to or greater than the upper limit value in step S12, the control section 31 infers that the state of the device 70 is an abnormal state. Also, the control section 31 outputs an inference result indicating that the state of the device 70 is an abnormal state.

[0267] 〈Step S14〉

[0268] On the other hand, when the first frequency component is not equal to or greater than the upper limit value in step S12, the control section 31 infers that the state of the device 70 is a normal state. Also, the control section 31 outputs an inference result indicating that the state of the device 70 is a normal state.

[0269] 〔Second Inference Processing〕

[0270] The following describes the second inference processing with reference to Figure 7 and Figure 8 . In the second inference processing, the control section 31 infers whether the state of the device 70 is an abnormal state based on the rate of change of the first frequency component. Specifically, the control section 31 performs the following processing (steps S21 to S23) at each of the preset detection periods.

[0271] <Step S21>

[0272] The control unit 31 acquires the rate of change of the first frequency component. For example, the control unit 31 derives the rate of change of the first frequency component by differentiating it with respect to time. Figure 8 In the example, the rate of change of the first frequency component changes at times t1, t2, and t3, respectively.

[0273] <Step S22>

[0274] The control unit 31 determines whether the rate of change of the first frequency component obtained in step S21 is above a preset upper limit value. It should be noted that this upper limit value is an example of a threshold value used in the inference process. If the rate of change of the first frequency component is above the upper limit value, then step S23 is performed. Otherwise, step S24 is performed. Figure 8 In the example, the rate of change of the first frequency component reaches above the upper limit at time t2.

[0275] <Step S23>

[0276] When the rate of change of the first frequency component exceeds the upper limit in step S22, the control unit 31 infers that the state of the device 70 is abnormal. Furthermore, the control unit 31 outputs the inference result indicating that the state of the device 70 is abnormal.

[0277] <Step S24>

[0278] On the other hand, when the rate of change of the first frequency component is not above the upper limit value in step S22, the control unit 31 infers that the state of the device 70 is normal. Furthermore, the control unit 31 outputs the inference result indicating that the state of the device 70 is normal.

[0279] [Third Inference Process]

[0280] Reference Figure 9 and Figure 10 The third inference process will now be explained. In the third inference process, the control unit 31 infers whether the state of the device 70 is abnormal based on the accumulated time, which is obtained by accumulating the time when the first frequency component reaches or exceeds the upper limit value. Specifically, the control unit 31 repeatedly performs the following processes (steps S31 to S33) in each preset detection cycle.

[0281] <Step S31>

[0282] The control unit 31 acquires the cumulative value (cumulative time) of the time when the first frequency component is above the upper limit value. It should be noted that this upper limit value is an example of a threshold used in the inference process.

[0283] For example, the control section 31 acquires the first frequency component that is a representative value of the detection period, and determines whether the first frequency component is above the upper limit value. Also, when the first frequency component is above the upper limit value, the control section 31 increments the count value, and when the first frequency component is not above the upper limit value, the control section 31 does not increment the count value. This count value corresponds to a cumulative value (cumulative time) of the time during which the first frequency component is above the upper limit value. For example, the cumulative time is the value obtained by multiplying the count value by the time corresponding to the detection period.

[0284] In Figure 10 the example, the third inference processing is performed at times t1 to t12, and the count value is incremented at times t2 to t5 and t9 to t12 among the times t1 to t12.

[0285] <Step S32>

[0286] Next, the control section 31 determines whether the cumulative time (in this example, the count value) acquired in step S31 exceeds a predetermined threshold value. This threshold value is an example of the threshold value used in the inference processing. When the cumulative time exceeds the threshold value, the processing of step S33 is performed, and otherwise, the processing of step S34 is performed. In Figure 10 the example, the control section 31 determines that the count value exceeds the threshold value at time t11.

[0287] <Step S33>

[0288] When the cumulative time exceeds the threshold value in step S32, the control section 31 infers that the state of the device 70 is an abnormal state. Also, the control section 31 outputs the inference result indicating that the state of the device 70 is an abnormal state.

[0289] <Step S34>

[0290] On the other hand, when the cumulative time does not exceed the threshold value in step S32, the control section 31 infers that the state of the device 70 is a normal state. Also, the control section 31 outputs the inference result indicating that the state of the device 70 is a normal state.

[0291] [Fourth Inference Processing]

[0292] The fourth inference processing will be described with reference to Figure 11 and Figure 12 In the fourth inference processing, the control section 31 infers whether the state of the device 70 is an abnormal state, based on a ratio (time ratio) of the time during which the first frequency component is above a predetermined upper limit value within a predetermined determination time. Specifically, the control section 31 repeatedly performs the following processing (steps S41 to S43) at each predetermined detection period.

[0293] <Step S41>

[0294] The control section 31 acquires a ratio (time ratio) of a time when the first frequency component is equal to or higher than the upper limit value within the judgment time. Note that the upper limit value is an example of the threshold value used in the inference processing.

[0295] For example, the control section 31 stores the first frequency component within a judgment period (a period equivalent to at least the judgment time) that ends at the current time. Then, the control section 31 derives a time (upper limit value exceeding time) when the first frequency component is equal to or higher than the upper limit value within a judgment period that ends at the current time and has a period length equivalent to the judgment time, and derives the time ratio by dividing the upper limit value exceeding time by the judgment time. Note that in the example of FIG. 6, the time t2 is the current time, the period from the time t1 to the time t2 is the judgment period, the time T1 and the time T2 are the upper limit value exceeding time, and the value obtained by dividing the sum of the time T1 and the time T2 by the judgment time T0 is the time ratio. Figure 12

[0296] 〈Step S42〉

[0297] Next, the control section 31 determines whether or not the time ratio (ratio of a time when the first frequency component is equal to or higher than the upper limit value within the judgment time) acquired in step S41 exceeds a predetermined threshold value. Note that the threshold value is an example of the threshold value used in the inference processing. When the time ratio exceeds the threshold value, the process of step S43 is performed. Otherwise, the process of step S44 is performed.

[0298] 〈Step S43〉

[0299] When the time ratio exceeds the threshold value in step S42, the control section 31 infers that the state of the device 70 is an abnormal state. Then, the control section 31 outputs the inference result indicating that the state of the device 70 is an abnormal state.

[0300] 〈Step S44〉

[0301] On the other hand, when the time ratio does not exceed the threshold value in step S42, the control section 31 infers that the state of the device 70 is a normal state. Then, the control section 31 outputs the inference result indicating that the state of the device 70 is a normal state.

[0302] Note that in the description of the above inference processing, the case where the first frequency component is compared with the upper limit value is exemplified, but the present technology is not limited to this. For example, the first frequency component can be compared with a predetermined lower limit value. That is, the above "equal to or higher than the upper limit value" can be replaced with "equal to or lower than the lower limit value". Further, the first frequency component can be compared with a predetermined allowable range. That is, the above "equal to or higher than the upper limit value" can be replaced with "outside the allowable range".

[0303] ​(Specific examples of the process for limiting the inference processing)

[0304] Next, specific examples of the "process for limiting the inference processing" performed in the limiting process will be described. The process for limiting the inference processing includes, for example, the following five processes (first to fifth processes).

[0305] [First process]

[0306] First, the first process will be described. In the first process, the control section 31 stops the inference processing, and outputs the preset inference result. In this way, the inference processing is directly limited so as to output the preset inference result.

[0307] [Second process]

[0308] Next, the second process will be described. In the second process, the control section 31 continues the inference processing, and on the other hand, corrects the inference result obtained by the inference processing to the "preset inference result". In this way, the inference processing is directly limited so as to output the preset inference result.

[0309] [Third process]

[0310] Next, the third process will be described. In the third process, the control section 31 stops the calculation processing, and sets the feature amount used in the inference processing to the "preset feature amount" so as to obtain the preset inference result in the inference processing. In this way, the inference processing is indirectly limited so as to output the preset inference result.

[0311] [Fourth process]

[0312] Next, the fourth process will be described. In the fourth process, the control section 31 continues the calculation processing, and on the other hand, corrects the feature amount calculated by the calculation processing to the "preset feature amount" so as to obtain the preset inference result in the inference processing. In this way, the inference processing is indirectly limited so as to output the preset inference result.

[0313] [Fifth process]

[0314] Next, the fifth process will be described. In the fifth process, the control section 31 corrects the threshold value used in the inference processing to the "preset threshold value" so as to obtain the preset inference result in the inference processing. In this way, the inference processing is directly limited so as to output the preset inference result.

[0315] (Specific examples of the standby release condition)

[0316] Next, specific examples of the standby release condition will be described. The standby release condition includes, for example, the following three standby release conditions (first to third standby release conditions).

[0317] 〔First standby release condition〕

[0318] First, the first standby release condition will be described. The first standby release condition is a condition that a prescribed time elapses from the time when the restriction release condition is established. When the restriction release condition is established, the control section 31 releases the restriction on the inference processing after the prescribed time elapses. Specifically, when the restriction release condition is established, the control section 31 starts measuring the elapsed time. And, when the elapsed time reaches the prescribed time, the control section 31 releases the restriction on the inference processing. Note that the prescribed time is set to, for example, a time longer than the time required for the characteristic quantity to change from the unstable state to the stable state. Or, the prescribed time can be set to a time longer than the time corresponding to the prescribed period. Note that the prescribed period is the "prescribed period" of the "physical quantity obtained from the device 70 in the prescribed period".

[0319] 〔Second standby release condition〕

[0320] Next, the second standby release condition will be described. The second standby release condition is a condition that the number of consecutive times that the restriction release condition is established reaches a prescribed number. The control section 31 repeatedly judges whether the restriction release condition is established, and when the restriction release condition is established, releases the restriction on the inference processing after the number of consecutive times that the restriction release condition is established reaches the prescribed number. Specifically, when the restriction release condition is established, the control section 31 starts measuring the number of consecutive times that the restriction release condition is established. And, when the number of consecutive times that the restriction release condition is established reaches the prescribed number, the control section 31 releases the restriction on the inference processing. Note that the prescribed number is set to, for example, a number larger than the number of consecutive times that the restriction release condition is established measured until the characteristic quantity changes from the unstable state to the stable state.

[0321] 〔Third standby release condition〕

[0322] Next, the third standby release condition will be described. The third standby release condition is a condition that the characteristic quantity calculated by the calculation processing reaches the stable state. The control section 31 monitors the characteristic quantity calculated by the calculation processing, and when the restriction release condition is established, releases the restriction on the inference processing after the characteristic quantity calculated by the calculation processing reaches the stable state. Specifically, when the restriction release condition is established, the control section 31 judges whether the characteristic quantity calculated by the calculation processing is in the stable state. And, when the control section 31 judges that the characteristic quantity calculated by the calculation processing is in the stable state, the control section 31 releases the restriction on the inference processing.

[0323] Note that the stable state of the feature quantity is, for example, a state in which a ratio of a current value of a moving average value of the feature quantity in a prescribed time to a previous value is within a prescribed range. For example, the moving average value in the prescribed time is a moving average value in 1 second, the previous value is a moving average value acquired 1 second before (one previous) the current value, and the prescribed range is 99 to 101%. The unstable state of the feature quantity is a state in which the ratio of the current value of the moving average value of the feature quantity in the prescribed time to the previous value is outside the prescribed range.

[0324] (Second Embodiment)

[0325] The inference restriction condition and the restriction release condition of the drive system 10 of the second embodiment are different from those of the drive system 10 of the first embodiment. The other configurations and processes of the drive system 10 of the second embodiment are the same as those of the drive system 10 of the first embodiment.

[0326] The inference restriction condition of the second embodiment is a condition in which the control mode of the motor 50 is changed. The restriction release condition of the second embodiment is a condition in which the control mode of the motor 50 is changed after the inference restriction condition is established. In the restriction process of the second embodiment, when the control mode of the motor 50 is changed, the control section 31 restricts the inference process so as to output a preset inference result, and then, when the control mode of the motor 50 is changed, the control section 31 releases the restriction on the inference process after a prescribed standby release condition is established.

[0327] For example, the inference restriction condition of the second embodiment is a condition in which the control mode of the motor 50 is changed from "a prescribed control mode" to "another control mode other than the prescribed control mode", and the restriction release condition of the second embodiment is a condition in which the control mode of the motor 50 is changed from "the other control mode other than the prescribed control mode" to "the prescribed control mode". Alternatively, the inference restriction condition of the second embodiment is a condition in which the control mode of the motor 50 is changed from "the other control mode other than the prescribed control mode" to "the prescribed control mode", and the restriction release condition of the second embodiment is a condition in which the control mode of the motor 50 is changed from "the prescribed control mode" to "the other control mode other than the prescribed control mode".

[0328] Note that the management of the control mode of the motor 50 can also be performed by the control section 31. For example, the control section 31 stores mode information indicating the current control mode of the motor 50 into a storage section (omitted from illustration), and if the control mode of the motor 50 is changed, the mode information stored in the storage section is updated.

[0329] Further, the control modes include, for example, field weakening control, speed droop control, start-up control, beat frequency suppression control, torque control, resonance suppression control, cogging torque ripple suppression control, modulation method switching control, square wave drive control, and the like. The speed droop control is a control mode that limits the current vector amplitude by speed droop. The start-up control is a control mode performed when the motor 50 is started. The beat frequency suppression control is a control mode that suppresses a beat frequency phenomenon caused by the power supply frequency and the rotational frequency. The torque control is a control mode that varies the output torque of the motor 50 in accordance with a variation in load torque in order to suppress vibration of the compressor. The resonance suppression control is a control mode that suppresses resonance caused by the reactor and the capacitor. The cogging torque ripple suppression control is a control mode that suppresses power pulsation caused by cogging torque ripple. The modulation method switching control is a control mode that switches the modulation method. The modulation method switching control is disclosed in Japanese Patent No. 6103031 and the like.

[0330] For example, the inference restriction condition of the second embodiment is a condition that changes from "other control modes than the field weakening control among the above control modes" to "the field weakening control". The restriction release condition of the second embodiment is a condition that changes from "the field weakening control" to "other control modes than the field weakening control among the above control modes".

[0331] [Effects of the Second Embodiment]

[0332] In the second embodiment, the same effects as those of the first embodiment can also be obtained.

[0333] Further, in the second embodiment, the inference restriction condition is a condition that the control mode of the motor 50 changes. The restriction release condition is a condition that the control mode of the motor 50 changes after the inference restriction condition is established.

[0334] In the second embodiment, the change in the control mode of the motor 50 is related to an unexpected variation in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. For example, when the control mode of the motor 50 does not change, there is a tendency that the characteristic quantity is less likely to vary unexpectedly, and when the control mode of the motor 50 changes, there is a tendency that the characteristic quantity is likely to vary unexpectedly within a period immediately after the change. By monitoring the change in the control mode of the motor 50, it can be confirmed whether the characteristic quantity varies unexpectedly. Therefore, by performing the restriction and the restriction release of the inference processing in accordance with the change in the control mode of the motor 50, the restriction and the restriction release of the inference processing can be appropriately performed.

[0335] (Modified Example of the Second Embodiment)

[0336] When the inference restriction condition of the second embodiment is the condition that "the control mode of the motor 50 is changed", the inference restriction condition of the second embodiment can also be the condition that "the inference processing is restricted in accordance with the change of the control mode of the motor 50". In this case, in the restriction processing, when the control mode of the motor 50 is changed, the control section 31 restricts the inference processing so as to output the preset inference result, and then the control section 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0337] As described above, the inference restriction condition of the second embodiment can be the first condition that "the control mode of the motor 50 is changed after the inference processing is restricted" or the second condition that "when the inference restriction condition is the condition that the control mode of the motor 50 is changed, the inference processing is restricted in accordance with the change of the control mode of the motor 50".

[0338] (Third Embodiment)

[0339] The inference restriction condition and the release condition of the drive system 10 of the third embodiment are different from those of the drive system 10 of the first embodiment. The other configurations and processing of the drive system 10 of the third embodiment are the same as those of the drive system 10 of the first embodiment.

[0340] The inference restriction condition of the third embodiment is the condition that "the integer multiple of the frequency of the voltage of the power supply 60 is near the integer multiple or the M / N multiple of the rotational frequency of the motor 50". Note that M and N are integers. For example, M / N is 1 / 3 or 2 / 3. The release condition of the third embodiment is the condition that "the integer multiple of the frequency of the voltage of the power supply 60 deviates from near the integer multiple or the M / N multiple of the rotational frequency of the motor 50". In the restriction processing of the third embodiment, when the integer multiple of the frequency of the voltage of the power supply 60 is near the integer multiple or the M / N multiple of the rotational frequency of the motor 50, the control section 31 restricts the inference processing so as to output the preset inference result, and when the integer multiple of the frequency of the voltage of the power supply 60 deviates from near the integer multiple or the M / N multiple of the rotational frequency of the motor 50, the control section 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0341] Note that the voltage of the power supply 60 can also be detected by a power supply voltage detection section (not shown) provided in the drive system 10, for example. The voltage of the power supply 60 detected by the power supply voltage detection section is transmitted to the control section 31. The control section 31 can also derive the frequency of the voltage of the power supply 60 by monitoring the voltage of the power supply 60.

[0342] In addition, the rotational frequency of the motor 50 can be derived by the electric angle frequency detection section 42, for example, from the electric angle frequency ω of the motor 50. The derivation of the rotational frequency of the motor 50 can be performed by the control section 31. Alternatively, the rotational frequency of the motor 50 can be detected by a rotational frequency detection section (not shown) provided in the drive system 10. The rotational frequency of the motor 50 detected by the rotational frequency detection section is transmitted to the control section 31.

[0343] Further, the state that "the integer multiple of the frequency of the voltage of the power supply 60 is in the vicinity of the integer multiple or the M / N multiple of the rotational frequency of the motor 50" is, for example, a state that the difference between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50 is within 1 Hz. The state that "the integer multiple of the frequency of the voltage of the power supply 60 is in the vicinity of the integer multiple or the M / N multiple of the rotational frequency of the motor 50" is a state that the difference between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50 is more than 1 Hz.

[0344] 〔Effects of the Third Embodiment〕

[0345] In the third embodiment, the same effects as those of the first embodiment can be obtained.

[0346] Further, in the third embodiment, the inference restriction condition is the condition that the integer multiple of the frequency of the voltage of the power supply 60 is in the vicinity of the integer multiple or the M / N multiple of the rotational frequency of the motor 50. The inference release condition is the condition that the integer multiple of the frequency of the voltage of the power supply 60 deviates from the vicinity of the integer multiple or the M / N multiple of the rotational frequency of the motor 50.

[0347] In the third embodiment, the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50 is related to the unexpected fluctuation of the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. For example, when the integer multiple of the frequency of the voltage of the power supply 60 deviates from the vicinity of the integer multiple or the M / N multiple of the rotational frequency of the motor 50, there is a tendency that the characteristic quantity is difficult to fluctuate unexpectedly; when the integer multiple of the frequency of the voltage of the power supply 60 is in the vicinity of the integer multiple or the M / N multiple of the rotational frequency of the motor 50, there is a tendency that the characteristic quantity is easy to fluctuate unexpectedly. By monitoring the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50, it is possible to confirm whether the characteristic quantity has fluctuated unexpectedly. Therefore, by performing the restriction and the release of the inference processing in accordance with the relationship between the integer multiple of the frequency of the voltage of the power supply 60 and the integer multiple or the M / N multiple of the rotational frequency of the motor 50, it is possible to appropriately perform the restriction and the release of the inference processing.

[0348] (Fourth Embodiment)

[0349] The inference restriction condition and the restriction release condition of the drive system 10 of the fourth embodiment are different from those of the drive system 10 of the first embodiment. The other configurations and processes of the drive system 10 of the fourth embodiment are the same as those of the drive system 10 of the first embodiment.

[0350] The inference restriction condition of the fourth embodiment is a condition in which the voltage of the direct current section 22 changes from the stable state to the unstable state. The restriction release condition of the fourth embodiment is a condition in which the voltage of the direct current section 22 changes from the unstable state to the stable state. In the restriction process of the fourth embodiment, when the voltage of the direct current section 22 changes from the stable state to the unstable state, the control section 31 restricts the inference process so as to output the preset inference result, and when the voltage of the direct current section 22 changes from the unstable state to the stable state, the control section 31 releases the restriction on the inference process after the prescribed standby release condition is satisfied.

[0351] Note that the voltage of the direct current section 22 can be detected by a direct current voltage detection section (not shown) provided in the drive system 10, for example. The voltage of the direct current section 22 detected by the direct current voltage detection section is transmitted to the control section 31.

[0352] Further, the stable state of the voltage of the direct current section 22 is a state in which the instantaneous value of the alternating component extracted from the instantaneous waveform of the voltage of the direct current section 22 is below a threshold value, for example. The threshold value is set to a value obtained by multiplying the average value of the alternating component extracted from the instantaneous waveform of the voltage of the direct current section 22 by a prescribed coefficient, for example. The unstable state of the voltage of the direct current section 22 is a state in which the instantaneous value of the alternating component extracted from the instantaneous waveform of the voltage of the direct current section 22 is greater than the threshold value.

[0353] 〔Effects of the fourth embodiment〕

[0354] In the fourth embodiment, the same effects as those of the first embodiment can be obtained.

[0355] Further, in the fourth embodiment, the inference restriction condition is a condition in which the voltage of the direct current section 22 changes from the stable state to the unstable state. The restriction release condition is a condition in which the voltage of the direct current section 22 changes from the unstable state to the stable state.

[0356] In the fourth embodiment, the state of the voltage of the direct current section 22 is related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. For example, when the voltage of the direct current section 22 is in a stable state, there is a tendency that the characteristic quantity is less likely to change unexpectedly; when the voltage of the direct current section 22 is in an unstable state, there is a tendency that the characteristic quantity is more likely to change unexpectedly. By monitoring the state of the voltage of the direct current section 22, it is possible to confirm whether the characteristic quantity has changed unexpectedly. Therefore, by restricting and releasing the restriction of the inference processing in accordance with the change in the state of the voltage of the direct current section 22, it is possible to appropriately restrict and release the restriction of the inference processing.

[0357] (Fifth Embodiment)

[0358] Figure 13 A configuration example of the drive system 10 of the fifth embodiment will be described. The drive system 10 of the fifth embodiment is installed on the device 70 on which the compressor CC having the motor 50 is installed. The inference restriction condition and the restriction release condition of the drive system 10 of the fifth embodiment are different from those of the drive system 10 of the first embodiment. The other configurations and processes of the drive system 10 of the fifth embodiment are the same as those of the drive system 10 of the first embodiment.

[0359] In the drive system 10 of the fifth embodiment, the control device 30 is an example of a state inferring device that infers the state of the device 70 on which the compressor CC having the motor 50 is installed.

[0360] The inference restriction condition of the fifth embodiment is a condition in which the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from a stable state to an unstable state. Note that the fluid flowing into the compressor CC is, for example, the fluid sucked by the suction port of the compressor CC, the fluid supplied to the injection port of the compressor CC. The fluid flowing out of the compressor CC is, for example, the fluid discharged from the discharge port of the compressor CC. Hereinafter, the pressure of the fluid flowing into the compressor CC will be referred to as "inflow pressure", and the pressure of the fluid flowing out of the compressor CC will be referred to as "outflow pressure".

[0361] Specifically, the inference restriction condition of the fifth embodiment is a condition in which either one of the inflow pressure and the outflow pressure of the compressor CC is monitored and the pressure becomes a monitored pressure that changes from a stable state to an unstable state. Alternatively, the inference restriction condition of the fifth embodiment is a condition in which both of the inflow pressure and the outflow pressure of the compressor CC are monitored and at least one of the inflow pressure and the outflow pressure of the compressor CC changes from a stable state to an unstable state.

[0362] The restriction release condition of the fifth embodiment is a condition in which the inflow pressure or the outflow pressure of the compressor CC changes from the unstable state to the stable state. Note that, in the restriction release condition of the fifth embodiment, either one of the inflow pressure and the outflow pressure of the compressor CC is the monitored pressure.

[0363] Specifically, the restriction release condition of the fifth embodiment is a condition in which either one of the inflow pressure and the outflow pressure of the compressor CC is the monitored pressure and the monitored pressure changes from the unstable state to the stable state. Alternatively, the restriction release condition of the fifth embodiment is a condition in which both of the inflow pressure and the outflow pressure of the compressor CC are the monitored pressures and both of the inflow pressure and the outflow pressure of the compressor CC become the unstable state.

[0364] In the restriction processing of the fifth embodiment, when either one of the inflow pressure and the outflow pressure of the compressor CC changes from the stable state to the unstable state, the control unit 31 restricts the inference processing so as to output the preset inference result, and when either one of the inflow pressure and the outflow pressure of the compressor CC changes from the unstable state to the stable state, the control unit 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0365] Specifically, in the restriction processing of the fifth embodiment, when either one of the inflow pressure and the outflow pressure of the compressor CC (the monitored pressure) changes from the stable state to the unstable state, the control unit 31 restricts the inference processing so as to output the preset inference result, and when either one of the inflow pressure and the outflow pressure of the compressor CC (the monitored pressure) changes from the unstable state to the stable state, the control unit 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0366] Alternatively, in the restriction processing of the fifth embodiment, when at least one of the inflow pressure and the outflow pressure of the compressor CC changes from the stable state to the unstable state, the control unit 31 restricts the inference processing so as to output the preset inference result, and when both of the inflow pressure and the outflow pressure of the compressor CC become the stable state, the control unit 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0367] Note that the inflow pressure of the compressor CC can also be detected by an inflow pressure detection unit (not shown) provided at the inflow portion (e.g., the suction port) of the compressor CC. The inflow pressure of the compressor CC detected by the inflow pressure detection unit is transmitted to the control unit 31. Also, the outflow pressure of the compressor CC can also be detected by an outflow pressure detection unit (not shown) provided at the outflow portion (e.g., the discharge port) of the compressor CC. The outflow pressure of the compressor CC detected by the outflow pressure detection unit is transmitted to the control unit 31.

[0368] Further, the stable state of the inflow pressure of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the inflow pressure of the compressor CC is within a prescribed difference. For example, the previous value is the inflow pressure of the compressor CC acquired one second before the present value, and the prescribed difference is 0.1 MPa. The unstable state of the inflow pressure of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the inflow pressure of the compressor CC is greater than the prescribed difference.

[0369] Alternatively, the stable state of the inflow pressure of the compressor CC can also be a state in which the difference between the present value and the previous value of the saturation temperature of the fluid flowing into the compressor CC is within a prescribed difference. Hereinafter, the saturation temperature of the fluid flowing into the compressor CC is referred to as "inflow saturation temperature". For example, the previous value is the inflow saturation temperature of the compressor CC acquired one second before the present value, and the prescribed difference is 0.1°C. The unstable state of the inflow pressure of the compressor CC can also be a state in which the difference between the present value and the previous value of the inflow saturation temperature of the compressor CC is greater than the prescribed difference.

[0370] Alternatively, the stable state of the inflow pressure of the compressor CC can also be a state in which the difference between the moving average of the inflow pressure of the compressor CC over a first time and the moving average of the inflow pressure of the compressor CC over a second time is within a prescribed difference. The second time is shorter than the first time. For example, the moving average over the first time is a moving average over 3 minutes, the moving average over the second time is a moving average over 10 seconds, and the prescribed difference is 1°C. The unstable state of the inflow pressure of the compressor CC can also be a state in which the difference between the moving average of the inflow pressure of the compressor CC over the first time and the moving average of the inflow pressure of the compressor CC over the second time is greater than the prescribed difference.

[0371] Further, the stable state of the outflow pressure of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the outflow pressure of the compressor CC is within a prescribed difference. For example, the previous value is the outflow pressure of the compressor CC acquired one second before the present value, and the prescribed difference is 0.1 MPa. The unstable state of the outflow pressure of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the outflow pressure of the compressor CC is greater than the prescribed difference.

[0372] Alternatively, the stable state of the outflow pressure of the compressor CC can also be a state in which the difference between the present value and the previous value of the saturation temperature of the fluid flowing out of the compressor CC is within a prescribed difference. Hereinafter, the saturation temperature of the fluid flowing out of the compressor CC is referred to as "outflow saturation temperature". For example, the previous value is the outflow saturation temperature of the compressor CC acquired one second before the present value, and the prescribed difference is 0.1°C. The unstable state of the outflow pressure of the compressor CC can also be a state in which the difference between the present value and the previous value of the outflow saturation temperature of the compressor CC is greater than the prescribed difference.

[0373] Alternatively, the steady state of the outflow pressure of the compressor CC can also be a state in which the difference between the moving average of the outflow pressure of the compressor CC over a first time and the moving average of the outflow pressure of the compressor CC over a second time is within a prescribed difference. The second time is shorter than the first time. For example, the moving average over the first time is a moving average over 3 minutes, the moving average over the second time is a moving average over 10 seconds, and the prescribed difference is 1°C. The non-steady state of the outflow pressure of the compressor CC can also be a state in which the difference between the moving average of the outflow pressure of the compressor CC over the first time and the moving average of the outflow pressure of the compressor CC over the second time is greater than the prescribed difference.

[0374] (EFFECTS OF THE FIFTH EMBODIMENT)

[0375] In the fifth embodiment, the same effects as those of the first embodiment can also be obtained.

[0376] Further, in the fifth embodiment, the inference restriction condition is a condition in which the inflow pressure or the outflow pressure of the compressor CC changes from the steady state to the non-steady state. The inference release condition is a condition in which the inflow pressure or the outflow pressure of the compressor CC changes from the non-steady state to the steady state.

[0377] In the fifth embodiment, the state of the inflow pressure or the outflow pressure of the compressor CC is related to the unexpected fluctuation of the characteristic quantity calculated from the physical quantity obtained from the device 70 over a prescribed period. For example, when the inflow pressure and the outflow pressure of the compressor CC are in the steady state, there is a tendency that the characteristic quantity is less likely to fluctuate unexpectedly; when the inflow pressure or the outflow pressure of the compressor CC is in the non-steady state, there is a tendency that the characteristic quantity is more likely to fluctuate unexpectedly. By monitoring the state of the inflow pressure or the outflow pressure of the compressor CC, it can be confirmed whether the characteristic quantity has fluctuated unexpectedly. Therefore, by restricting and releasing the inference processing in accordance with the change in the state of the inflow pressure or the outflow pressure of the compressor CC, the restriction and the release of the inference processing can be appropriately performed.

[0378] (VARIATIONS OF THE FIFTH EMBODIMENT)

[0379] Note that, in the fifth embodiment, the control unit 31 can also determine the change of the inflow pressure or the outflow pressure of the compressor CC from the non-steady state to the steady state in accordance with the effective value or the current vector amplitude of the current flowing in the motor 50. Hereinafter, the current flowing in the motor 50 will be referred to as "motor current".

[0380] For example, when the condition changes from "the ratio of the current value to the previous value of the moving average of the effective value (or current vector amplitude) of the motor current over a specified time is outside a specified range" to "the ratio of the current value to the previous value of the moving average of the effective value (or current vector amplitude) of the motor current over a specified time is within a specified range," the control unit 31 can also determine that the inflow pressure (or outflow pressure) of the compressor CC has changed from an unstable state to a stable state. For example, the moving average of the previous value over the specified time is the moving average over 1 second, and the previous value is the moving average obtained 1 second before the current value (the previous one), with a specified range of 99% to 101%.

[0381] (Sixth Implementation Method)

[0382] and Figure 13 Similar to the drive system 10 of the fifth embodiment shown, the drive system 10 of the sixth embodiment is mounted on a device 70, on which a compressor CC having a motor 50 is mounted. The inference constraint conditions and constraint release conditions of the drive system 10 of the sixth embodiment differ from those of the drive system 10 of the first embodiment. Other configurations and processes of the drive system 10 of the sixth embodiment are the same as those of the drive system 10 of the first embodiment.

[0383] In the drive system 10 of the sixth embodiment, the control device 30 is an example of a state inference device that infers the state of a device 70 equipped with a compressor CC, which has an electric motor 50.

[0384] The limiting condition for the sixth embodiment is that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from a steady state to an unstable state. Hereinafter, the temperature of the fluid flowing into the compressor CC will be referred to as the "inflow temperature" and the temperature of the fluid flowing out of the compressor CC will be referred to as the "outflow temperature".

[0385] Specifically, the inference constraint of the sixth embodiment is that either the inlet temperature or the outlet temperature of the compressor CC is monitored, and the temperature of the monitored object changes from a stable state to an unstable state. Alternatively, the inference constraint of the sixth embodiment is that both the inlet temperature and the outlet temperature of the compressor CC are monitored, and at least one of the inlet temperature and the outlet temperature of the compressor CC changes from a stable state to an unstable state.

[0386] The restriction release condition of the sixth embodiment is a condition in which the inflow temperature or the outflow temperature of the compressor CC changes from the unstable state to the stable state. Note that, in the restriction release condition of the sixth embodiment, either of the inflow temperature and the outflow temperature of the compressor CC, which is the temperature that has become the monitoring target in the inference restriction condition, is the monitoring target.

[0387] Specifically, the restriction release condition of the sixth embodiment is a condition in which either of the inflow temperature and the outflow temperature of the compressor CC is the monitoring target and the temperature that becomes the monitoring target changes from the unstable state to the stable state. Alternatively, the restriction release condition of the sixth embodiment is a condition in which both of the inflow temperature and the outflow temperature of the compressor CC are the monitoring targets and both of the inflow temperature and the outflow temperature of the compressor CC become the unstable state.

[0388] In the restriction processing of the sixth embodiment, when either of the inflow temperature or the outflow temperature of the compressor CC changes from the stable state to the unstable state, the control unit 31 restricts the inference processing so as to output the preset inference result, and when either of the inflow temperature or the outflow temperature of the compressor CC changes from the unstable state to the stable state, the control unit 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0389] Specifically, in the restriction processing of the sixth embodiment, when either of the inflow temperature and the outflow temperature of the compressor CC, which is the temperature that becomes the monitoring target, changes from the stable state to the unstable state, the control unit 31 restricts the inference processing so as to output the preset inference result, and when either of the inflow temperature and the outflow temperature of the compressor CC, which is the temperature that becomes the monitoring target, changes from the unstable state to the stable state, the control unit 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0390] Alternatively, in the restriction processing of the sixth embodiment, when at least one of the inflow temperature and the outflow temperature of the compressor CC changes from the stable state to the unstable state, the control unit 31 restricts the inference processing so as to output the preset inference result, and when both of the inflow temperature and the outflow temperature of the compressor CC become the stable state, the control unit 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied.

[0391] Note that the inflow temperature of the compressor CC can also be detected by an inflow temperature detection unit (not shown) provided at the inflow portion (e.g., the suction port) of the compressor CC. The inflow temperature of the compressor CC detected by the inflow temperature detection unit is transmitted to the control unit 31. Likewise, the outflow temperature of the compressor CC can also be detected by an outflow temperature detection unit (not shown) provided at the outflow portion (e.g., the discharge port) of the compressor CC. The outflow temperature of the compressor CC detected by the outflow temperature detection unit is transmitted to the control unit 31.

[0392] Further, the stable state of the inflow temperature of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the inflow temperature of the compressor CC is within a prescribed difference. For example, the previous value is the inflow temperature of the compressor CC acquired 1 second before the present value, and the prescribed difference is 0.1°C. The unstable state of the inflow temperature of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the inflow temperature of the compressor CC is greater than the prescribed difference.

[0393] Alternatively, the stable state of the inflow temperature of the compressor CC can also be a state in which the difference between the moving average value of the inflow temperature of the compressor CC over a first time and the moving average value of the inflow temperature of the compressor CC over a second time is within a prescribed difference. The second time is shorter than the first time. For example, the moving average value over the first time is a moving average value over 3 minutes, the moving average value over the second time is a moving average value over 10 seconds, and the prescribed difference is 1°C. The unstable state of the inflow temperature of the compressor CC can also be a state in which the difference between the moving average value of the inflow temperature of the compressor CC over the first time and the moving average value of the inflow temperature of the compressor CC over the second time is greater than the prescribed difference.

[0394] Further, the stable state of the outflow temperature of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the outflow temperature of the compressor CC is within a prescribed difference. For example, the previous value is the outflow temperature of the compressor CC acquired 1 second before the present value, and the prescribed difference is 0.1°C. The unstable state of the outflow temperature of the compressor CC is, for example, a state in which the difference between the present value and the previous value of the outflow temperature of the compressor CC is greater than the prescribed difference.

[0395] Alternatively, the stable state of the outflow temperature of the compressor CC can also be a state in which the difference between the moving average value of the outflow temperature of the compressor CC over a first time and the moving average value of the outflow temperature of the compressor CC over a second time is within a prescribed difference. The second time is shorter than the first time. For example, the moving average value over the first time is a moving average value over 3 minutes, the moving average value over the second time is a moving average value over 10 seconds, and the prescribed difference is 1°C. The unstable state of the outflow temperature of the compressor CC can also be a state in which the difference between the moving average value of the outflow temperature of the compressor CC over the first time and the moving average value of the outflow temperature of the compressor CC over the second time is greater than the prescribed difference.

[0396] 〔Effects of the sixth embodiment〕

[0397] In the sixth embodiment, the same effects as those of the first embodiment can also be obtained.

[0398] Furthermore, in the sixth embodiment, the limiting condition is the condition that the inlet temperature or outlet temperature of the compressor CC changes from a steady state to an unstable state. The condition for lifting the limitation is the condition that the inlet temperature or outlet temperature of the compressor CC changes from an unstable state to a steady state.

[0399] In the sixth embodiment, the state of the inlet or outlet temperature of the compressor CC is related to unexpected changes in a characteristic quantity, which is calculated based on a physical quantity obtained from the device 70 within a specified period. For example, when the inlet and outlet temperatures of the compressor CC are stable, the characteristic quantity tends to be less prone to unexpected changes; when the inlet or outlet temperatures of the compressor CC are unstable, the characteristic quantity tends to be more prone to unexpected changes. By monitoring the state of the inlet or outlet temperature of the compressor CC, it is possible to confirm whether an unexpected change in the characteristic quantity has occurred. Therefore, by limiting and removing the inference process based on changes in the state of the inlet or outlet temperature of the compressor CC, appropriate limitations and removals of the inference process can be performed.

[0400] (Seventh Implementation)

[0401] and Figure 13 Similar to the drive system 10 of the fifth embodiment shown, the drive system 10 of the seventh embodiment is mounted on a device 70, on which a compressor CC having a motor 50 is mounted. The inference constraint conditions and constraint release conditions of the drive system 10 of the seventh embodiment differ from those of the drive system 10 of the first embodiment. Other configurations and processes of the drive system 10 of the seventh embodiment are the same as those of the drive system 10 of the first embodiment.

[0402] In the drive system 10 of the seventh embodiment, the control device 30 is an example of a state inference device that infers the state of a device 70 equipped with a compressor CC, which has an electric motor 50.

[0403] [Inference Restrictions]

[0404] The inference constraint in the seventh embodiment includes at least two of the first to sixth constraint conditions. In the seventh embodiment, the inference constraint condition is valid when at least one of the constraint conditions included in the inference constraint condition is valid. In this example, the inference constraint condition includes all the constraint conditions from the first to the sixth constraint conditions.

[0405] The first limiting condition is that the speed of the motor 50 changes from a steady state to an unstable state.

[0406] The second limiting condition is a condition that the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from a steady state to a non-steady state.

[0407] The third limiting condition is a condition that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from a steady state to a non-steady state.

[0408] The fourth limiting condition is a condition that the control mode of the motor 50 changes. For example, the fourth limiting condition is a condition that the control mode of the motor 50 changes from "a prescribed control mode" to "another control mode other than the prescribed control mode". Alternatively, the fourth limiting condition is a condition that the control mode of the motor 50 changes from "another control mode other than the prescribed control mode" to "the prescribed control mode".

[0409] The fifth limiting condition is that, when the motor 50 is driven by alternating current generated based on the power supply electric power supplied from the power supply 60, an integer multiple of the frequency of the voltage of the power supply 60 is near an integer multiple or M / N multiple of the rotational frequency of the motor 50. M and N are integers.

[0410] The sixth limiting condition is that the motor drive device 20 has a direct current portion 22 that generates direct current corresponding to the power supply electric power supplied from the power supply 60 and an inverter 23 that converts the direct current generated by the direct current portion 22 into alternating current through switching operation, and when the motor 50 is driven by the motor drive device 20, the voltage of the direct current portion 22 changes from a steady state to a non-steady state.

[0411] 〔Limitation release condition〕

[0412] The limitation release condition of the seventh embodiment includes at least two of the first to sixth release conditions. Specifically, the first to sixth release conditions correspond one-to-one to the first to sixth limiting conditions. The limitation release condition includes the release conditions of the first to sixth release conditions that correspond to the limiting conditions included in the inferred limiting condition. Further, in the seventh embodiment, the limitation release condition is established when all the release conditions included in the limitation release condition are established. In this case, the limitation release condition includes all the release conditions of the first to sixth release conditions.

[0413] The first release condition is a condition that the rotational speed of the motor 50 changes from a non-steady state to a steady state.

[0414] The second release condition is a condition that the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from a non-steady state to a steady state.

[0415] The third release condition is a condition that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from an unstable state to a stable state.

[0416] The fourth release condition is a condition that the control mode of the motor 50 changes (first condition). For example, the fourth release condition is a condition that the control mode of the motor 50 changes from "another control mode other than the prescribed control mode" to "the prescribed control mode". Alternatively, the fourth release condition is a condition that the control mode of the motor 50 changes from "the prescribed control mode" to "another control mode other than the prescribed control mode".

[0417] Alternatively, the fourth release condition is a condition (second condition) that when it is inferred that the restriction condition is a condition that the control mode of the motor 50 changes (fourth restriction condition), it is inferred that the inference processing is restricted in accordance with the change in the control mode of the motor 50.

[0418] The fifth release condition is that when the motor 50 is driven by the alternating current generated on the basis of the power supply electric power supplied from the power supply 60, the frequency of the voltage of the power supply 60 deviates from an integer multiple of the rotational frequency of the motor 50 or the vicinity of M / N times.

[0419] The sixth release condition is that the motor drive device 20 has a direct current portion 22 that generates direct current corresponding to the power supply electric power supplied from the power supply 60 and an inverter 23 that converts the direct current generated by the direct current portion 22 into alternating current through switching operation, and when the motor 50 is driven by the motor drive device 20, the voltage of the direct current portion 22 changes from an unstable state to a stable state.

[0420] In the restriction processing of the seventh embodiment, when at least one of the restriction conditions included in the inference restriction condition is established, the control portion 31 restricts the inference processing so as to output a preset inference result, and when all of the release conditions included in the restriction release condition are established, the control portion 31 releases the restriction on the inference processing after the prescribed standby release condition is established.

[0421] 〔Effects of the Seventh Embodiment〕

[0422] In the seventh embodiment, the same effects as those of the first embodiment can also be obtained.

[0423] Further, in the seventh embodiment, the inference restriction condition includes at least two of the first to sixth restriction conditions. The restriction release condition includes at least two of the first to sixth release conditions. In other words, in the seventh embodiment, the restriction on the inference processing and the release of the restriction are performed in accordance with at least two of the following (1) to (6).

[0424] (1) the state of the rotational speed of the motor 50

[0425] (2) the state of the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC

[0426] (3) the state of the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC

[0427] (4) the change in the control mode of the motor 50

[0428] (5) the relationship between an integral multiple of the frequency of the voltage of the power supply 60 and an integral multiple or M / N multiple of the rotational frequency of the motor 50

[0429] (6) the state of the voltage of the direct-current portion 22

[0430] In the seventh embodiment, the above (1) to (6) are related to an unexpected change in the characteristic quantity calculated from the physical quantity obtained from the device 70 within a prescribed period. By monitoring the above (1) to (6), it is possible to confirm whether or not the characteristic quantity has undergone an unexpected change. Therefore, by performing the restriction and the restriction release of the inference processing in accordance with the above (1) to (6), it is possible to appropriately perform the restriction and the restriction release of the inference processing.

[0431] (Variation of the seventh embodiment)

[0432] Note that the inference restriction condition of the seventh embodiment can also include the seventh restriction condition. For example, the inference restriction condition can also include the first to seventh restriction conditions. The seventh restriction condition is that the rotational speed of the motor 50 is a specific rotational speed and the inflow pressure and the outflow pressure of the compressor CC are specific pressures.

[0433] For example, the specific rotational speed and the specific pressures are set to be "the rotational speed of the motor 50" and "the inflow pressure and the outflow pressure of the compressor CC" when the state of the compressor CC is a chipping state in the case where the compressor CC is a scroll compressor.

[0434] Note that the chipping state is a state in which the orbiting scroll (not shown) and the fixed scroll (not shown) of the scroll compressor, that is, the compressor CC, are separated and movement becomes unstable. When the state of the compressor CC is the chipping state, the gaseous fluid can leak from the compression chamber formed between the fixed scroll and the orbiting scroll and the internal pressure state of the compression chamber can change. The change in the internal pressure state of the compression chamber affects the physical quantity obtained from the device 70 (for example, the first component of the current vector amplitude), and thus an erroneous inference can occur in the inference processing.

[0435] Further, the restriction release condition of the seventh embodiment can include the seventh release condition. For example, the restriction release condition can include the first to seventh release conditions. The seventh release condition is a condition that the rotation speed of the motor 50 is not the specific rotation speed or a condition that both the pressure of the fluid flowing into the compressor CC and the pressure of the fluid flowing out of the compressor CC are not the specific pressure.

[0436] (Eighth Embodiment)

[0437] The inference restriction condition and the restriction release condition of the drive system 10 of the eighth embodiment are different from those of the drive system 10 of the first embodiment. The other configurations and processes of the drive system 10 of the eighth embodiment are the same as those of the drive system 10 of the first embodiment. Further, the drive system 10 of the eighth embodiment is mounted on, for example, the device 70 on which the compressor CC having the motor 50 is mounted.

[0438] In the drive system 10 of the eighth embodiment, the control device 30 is an example of a state inferring device that infers the state of the device 70 on which the motor 50 is mounted.

[0439] 〔Inference Restriction Condition〕

[0440] The inference restriction condition of the eighth embodiment includes at least one of the first to sixth restriction conditions. In the eighth embodiment, the inference restriction condition is established when at least one of the restriction conditions included in the inference restriction condition is established. In this example, the inference restriction condition includes all of the first to sixth restriction conditions.

[0441] The first restriction condition is a condition that the rotation speed of the motor 50 changes from the stable state to the unstable state.

[0442] The second restriction condition is a condition that the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from the stable state to the unstable state when the motor 50 is provided in the compressor CC.

[0443] The third restriction condition is a condition that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from the stable state to the unstable state when the motor 50 is provided in the compressor CC.

[0444] The fourth restriction condition is a condition that the control mode of the motor 50 changes. For example, the fourth restriction condition is a condition that the control mode of the motor 50 changes from the "predetermined control mode" to the "other control mode other than the predetermined control mode". Alternatively, the fourth restriction condition is a condition that the control mode of the motor 50 changes from the "other control mode other than the predetermined control mode" to the "predetermined control mode".

[0445] The fifth restriction condition is that when the motor 50 is driven by the alternating current generated based on the electric power supplied from the power supply 60, an integer multiple of the frequency of the voltage of the power supply 60 is near an integer multiple or M / N multiple of the rotational frequency of the motor 50. M and N are integers.

[0446] The sixth restriction condition is that the motor drive device 20 has a direct current section 22 that generates direct current corresponding to the electric power supplied from the power supply 60 and an alternating current converter 23 that converts the direct current generated by the direct current section 22 into alternating current through switching operation, and when the motor 50 is driven by the motor drive device 20, the voltage of the direct current section 22 changes from a stable state to an unstable state.

[0447] 〔Restriction release condition〕

[0448] The restriction release condition of the eighth embodiment includes at least one of the first to sixth release conditions. Specifically, the first to sixth release conditions correspond one-to-one to the first to sixth restriction conditions. The restriction release condition includes the release conditions corresponding to the restriction conditions included in the inferred restriction condition. Further, in the eighth embodiment, the restriction release condition is established when all the release conditions included in the restriction release condition are established. In this case, the restriction release condition includes all the release conditions among the first to sixth release conditions.

[0449] The first release condition is a condition in which the rotational speed of the motor 50 changes from the unstable state to the stable state.

[0450] The second release condition is a condition in which when the motor 50 is provided in the compressor CC, the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from the unstable state to the stable state.

[0451] The third release condition is a condition in which when the motor 50 is provided in the compressor CC, the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from the unstable state to the stable state.

[0452] The fourth release condition is a condition in which the control mode of the motor 50 changes (first condition). For example, the fourth release condition is a condition in which the control mode of the motor 50 changes from "another control mode other than the prescribed control mode" to "the prescribed control mode". Alternatively, the fourth release condition is a condition in which the control mode of the motor 50 changes from "the prescribed control mode" to "another control mode other than the prescribed control mode".

[0453] Alternatively, the fourth release condition is a condition (second condition) under which the inference processing is limited according to a change in the control mode of the motor 50 when it is inferred that the restriction condition is a condition (fourth restriction condition) in which the control mode of the motor 50 is changed.

[0454] The fifth release condition is that an integer multiple of the frequency of the voltage of the power supply 60 deviates from an integer multiple or an M / N multiple of the rotational frequency of the motor 50 around the integer multiple or the M / N multiple when the motor 50 is driven by the alternating current generated based on the power supply electric power supplied from the power supply 60.

[0455] The sixth release condition is that the motor drive device 20 has a direct current portion 22 that generates direct current corresponding to the power supply electric power supplied from the power supply 60 and a direct alternating current converter 23 that converts the direct current generated by the direct current portion 22 into alternating current through switching operation, and the voltage of the direct current portion 22 is changed from an unstable state to a stable state when the motor 50 is driven by the motor drive device 20.

[0456] In the restriction processing of the eighth embodiment, the control portion 31 restricts the inference processing so as to output a preset inference result when at least one of the restriction conditions included in the inference restriction condition is satisfied, and the control portion 31 releases the restriction on the inference processing after the prescribed standby release condition is satisfied when all of the release conditions included in the restriction release condition are satisfied.

[0457] 〔Effects of the eighth embodiment〕

[0458] In the eighth embodiment, the same effects as those of the first embodiment can also be obtained.

[0459] Further, in the eighth embodiment, the inference restriction condition includes at least one of the first to sixth restriction conditions. The restriction release condition includes at least one of the first to sixth release conditions. In other words, in the eighth embodiment, the restriction on the inference processing and the release of the restriction are performed according to at least one of the following (1) to (6).

[0460] (1) State of rotational speed of motor 50

[0461] (2) State of pressure of fluid flowing into compressor CC or pressure of fluid flowing out of compressor CC

[0462] (3) State of temperature of fluid flowing into compressor CC or temperature of fluid flowing out of compressor CC

[0463] (4) Change in control mode of motor 50

[0464] (5) Relationship between integer multiple of frequency of voltage of power supply 60 and integer multiple or M / N multiple of rotational frequency of motor 50

[0465] (6) State of voltage of DC portion 22

[0466] In the eighth embodiment, the above (1) to (6) are related to unexpected variation of a characteristic quantity calculated from a physical quantity obtained from the device 70 in a prescribed period. By monitoring the above (1) to (6), it is possible to confirm whether or not the characteristic quantity has experienced unexpected variation. Therefore, by performing the restriction and the restriction release of the inference processing in accordance with the above (1) to (6), it is possible to appropriately perform the restriction and the restriction release of the inference processing.

[0467] (Variation of the eighth embodiment)

[0468] Note that the inference restriction condition of the eighth embodiment can also include the seventh restriction condition. For example, the inference restriction condition can also include the first to seventh restriction conditions. The "seventh restriction condition" of the variation of the eighth embodiment is the same as the "seventh restriction condition" of the variation of the seventh embodiment.

[0469] Further, the restriction release condition of the eighth embodiment can also include the seventh release condition. For example, the restriction release condition can also include the first to seventh release conditions. The "seventh release condition" of the variation of the eighth embodiment is the same as the "seventh release condition" of the variation of the seventh embodiment.

[0470] (Refrigeration system)

[0471] Figure 14 A configuration example of a refrigeration system RR is shown. The refrigeration system RR includes a refrigerant circuit RR1 filled with a refrigerant, a motor drive device 20, and a control device 30. Figure 14 The motor drive device 20 and the control device 30 shown are the motor drive device 20 and the control device 30 of any one of the first to seventh embodiments.

[0472] The refrigerant circuit RR1 has a compressor CC, 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 type refrigeration cycle.

[0473] The compressor CC has a compression mechanism Cca and a motor 50. The compression mechanism Cca is connected to the motor 50 through a rotating shaft. The motor 50 drives the compression mechanism Cca to rotate by driving the rotating shaft to rotate. The motor drive device 20 drives the motor 50. The control device 30 infers the state of the refrigeration system RR in which the compressor CC having the motor 50 is installed.

[0474] In the refrigeration cycle, the refrigerant flowing out of the compressor CC is heat-released in the heat-releasing device RR5. The refrigerant flowing out of the heat-releasing device RR5 is depressurized in the depressurizing device RR6, and evaporated in the evaporator RR7. And the refrigerant flowing out of the evaporator RR7 flows into the compressor CC.

[0475] 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. In addition, the air conditioner can also be a switching air conditioner which switches between refrigeration and heating. In this case, the air conditioner has a switching device (for example, a four-way reversing valve) which switches the circulation direction of the refrigerant. In addition, the refrigeration system RR can also be a water heater, a cooling unit, a cooling device which cools the air in a box, and the like. The cooling device cools the air in a refrigeration chamber, a freezing chamber, a container, and the like.

[0476] (Fan system)

[0477] Figure 15 A configuration example of the fan system FF is shown. The fan system FF includes a fan FF1, the motor drive device 20, and the control device 30. Figure 15 The motor drive device 20 and the control device 30 shown are the motor drive device 20 and the control device 30 of any one of the first to fourth embodiments.

[0478] The fan FF1 has a rotating body FFa having a blade, and a motor 50. The rotating body FFa is coupled to the motor 50 through a rotating shaft. The motor 50 drives the rotating body FFa to rotate by driving the rotating shaft to rotate. The motor drive device 20 drives the motor 50. The control device 30 estimates the state of the fan system FF in which the motor 50 is installed.

[0479] (Other embodiments)

[0480] In the above description, the state of the device 70 can be the state of the entire device 70, or the state of a part of the components included in the device 70. For example, when the device 70 is "an outdoor unit in which the compressor CC having the motor 50 is installed", the state of the device 70 can be the state of the outdoor unit, can be the state of the compressor CC, can be the state of the motor 50, or can be the state of other components in the outdoor unit.

[0481] In the above description, the example given is a signal based on the current or voltage of the motor 50 as a physical quantity obtained from the device 70, but it is not limited to this. For example, the physical quantity may be a signal representing the current supplied to the motor 50, a signal representing the voltage applied to the motor 50, a signal representing the rotational speed of the motor 50, a signal representing the vibration of the device 70, or a signal representing the sound of the device 70. The signal representing the vibration of the device 70 may also be obtained by a vibration sensor (not shown) provided on the device 70. The signal representing the sound of the device 70 may also be obtained by a microphone (not shown) provided on the device 70.

[0482] Furthermore, the above explanation cites examples... Figure 3 and Figure 4 The first frequency component C1 shown is an example of a characteristic quantity calculated from a physical quantity, but it is not limited to this. For example, the first frequency component C1 can be a frequency component that is an integer multiple of the mechanical angular frequency of the motor 50, or it can be a frequency component that is an integer fraction of the mechanical angular frequency of the motor 50. The characteristic quantity can be any characteristic quantity calculated from a physical quantity obtained from the device 70 within a specified period. For example, the characteristic quantity can be the effective value of the phase current or the average value of the current vector amplitude. In this way, the characteristic quantity can be a frequency component, an effective value, an average value, or other values.

[0483] Furthermore, the above description provides an example of inferring whether device 70 has any abnormalities during the inference process, but it is not limited to this.

[0484] For example, the control unit 31 can also infer the wear degree of a rotating shaft (not shown) driven by the motor 50 or its bearing (not shown) during the inference process. In this case, the control unit 31 can also infer the wear degree based on characteristic quantities; for example, the larger the characteristic quantity obtained from the calculation process, the higher the wear degree of the rotating shaft or bearing. It should be noted that the "preset inference result" output when the inference process for inferring the wear degree is restricted may include, for example, an inference result indicating that the wear degree of the device 70 is unknown, or an inference result indicating that the inference process is prohibited (stopped). Wear degree is an example of the degree of deterioration.

[0485] Furthermore, the control unit 31 can also infer the remaining lifespan of the motor 50 during the inference process. In this case, the control unit 31 can also infer the remaining lifespan based on characteristic values; for example, the larger the characteristic value obtained from the calculation process, the shorter the remaining lifespan of the motor 50. It should be noted that the "preset inference result" output when the inference process for inferring the remaining lifespan is restricted may include, for example, an inference result indicating that the remaining lifespan of the device 70 is unknown, or an inference result indicating that the inference process is prohibited (stopped). Remaining lifespan is an example of the degree of degradation.

[0486] Further, in the above description, the control section 31 can also be configured to perform the inference processing using an algorithm (an algorithm for inferring a state from a change in a signal) constructed by a neural network or machine learning.

[0487] Further, in the above description, the control section 31 can be implemented by one processor or by a plurality of processors. Further, the control section 31 can also be implemented by a plurality of arithmetic processing devices (computers) that communicate with each other via a communication network.

[0488] Further, in the above description, the processing “when a prescribed restriction release condition is established, release the restriction on the inference processing after a prescribed standby release condition is established” can also include the following processing: “when a prescribed restriction release condition is established and a duration of a state for which an inference result obtained in the inference processing (for example, inference processing restricted by a second processing, which is an example of a processing for restricting inference processing) is a prescribed inference result (for example, an inference result indicating that the device 70 is abnormal) is above a prescribed time, release the restriction on the inference processing and output the inference result obtained in the inference processing”.

[0489] The embodiments and modified examples have been described above, but it should be understood that various changes can be made to the configurations and details thereof without departing from the gist and scope of the claims. Further, the components involved in the above embodiments, modified examples, and other embodiments can also be appropriately combined or replaced.

[0490] For example, aspects of the present disclosure can also be the following aspects.

[0491] 〔Example of state inference device〕

[0492] A state inference device that infers a state of a device 70 in which a motor 50 is installed,

[0493] The state inference device includes a control section 31,

[0494] The control section 31 performs a calculation processing, an inference processing, and a restriction processing,

[0495] In the calculation processing, a characteristic quantity is calculated from a physical quantity obtained from the device 70 within a prescribed period,

[0496] In the inference processing, a state of the device 70 is inferred from the characteristic quantity calculated by the calculation processing,

[0497] In the restriction processing, when a prescribed inference restriction condition is established, the inference processing is restricted so as to output a preset inference result, and when a prescribed restriction release condition is established, the restriction on the inference processing is released after a prescribed standby release condition is established,

[0498] The release condition includes at least one of a first release condition, a second release condition, a third release condition, a fourth release condition, a fifth release condition, and a sixth release condition,

[0499] The first release condition is that the rotation speed of the motor 50 changes from an unstable state to a stable state.

[0500] The second release condition is that, when the motor 50 is provided in a compressor CC, the pressure of fluid flowing into the compressor CC or the pressure of fluid flowing out of the compressor CC changes from an unstable state to a stable state.

[0501] The third release condition is that, when the motor 50 is provided in a compressor CC, the temperature of fluid flowing into the compressor CC or the temperature of fluid flowing out of the compressor CC changes from an unstable state to a stable state.

[0502] The fourth release condition is a first condition that the control mode of the motor 50 changes after the inference processing is limited or a second condition that, when the inference release condition is the condition that the control mode of the motor 50 changes, the inference processing is limited in accordance with the change in the control mode of the motor 50.

[0503] The fifth release condition is that, when the motor 50 is driven by alternating current generated on the basis of power supply electric power supplied from a power supply 60, the frequency of the voltage of the power supply 60 deviates from an integer multiple of the rotation frequency of the motor 50 or from the vicinity of an M / N (M and N are integers) multiple.

[0504] The sixth release condition is that the motor drive device 20 has a direct current portion 22 that generates direct current corresponding to power supply electric power supplied from a power supply 60 and a conversion portion 23 that converts the direct current generated by the direct current portion 22 into alternating current through switching operation, and, when the motor 50 is driven by the motor drive device 20, the voltage of the direct current portion 22 changes from an unstable state to a stable state.

[0505] The release condition is established when all the conditions included in the release condition are established.

[0506] Example of state inference method

[0507] A state inference method infers the state of an apparatus 70 in which a motor 50 is installed,

[0508] The state inferring method includes a calculating step in which a characteristic quantity is calculated from a physical quantity obtained from the device 70 over a prescribed period, an inferring step in which a state of the device 70 is inferred from the characteristic quantity calculated by the calculating step, and a restricting step in which the inferring step is restricted so as to output a preset inferring result when a prescribed inferring restriction condition is satisfied, and the restriction on the inferring step is released after a prescribed standby release condition is satisfied when a prescribed restriction release condition is satisfied.

[0509] In the inferring step, a state of the device 70 is inferred from the characteristic quantity calculated by the calculating step,

[0510] In the restricting step, the inferring step is restricted so as to output a preset inferring result when a prescribed inferring restriction condition is satisfied, and the restriction on the inferring step is released after a prescribed standby release condition is satisfied when a prescribed restriction release condition is satisfied,

[0511] The restriction release condition includes at least one of a first release condition, a second release condition, a third release condition, a fourth release condition, a fifth release condition, and a sixth release condition,

[0512] The first release condition is that a rotational speed of the motor 50 changes from a non-stable state to a stable state.

[0513] The second release condition is that, when the motor 50 is provided in a compressor CC, a pressure of a fluid flowing into the compressor CC or a pressure of a fluid flowing out of the compressor CC changes from a non-stable state to a stable state.

[0514] The third release condition is that, when the motor 50 is provided in a compressor CC, a temperature of a fluid flowing into the compressor CC or a temperature of a fluid flowing out of the compressor CC changes from a non-stable state to a stable state.

[0515] The fourth release condition is a first condition that a control mode of the motor 50 changes after the inferring processing is restricted or a second condition that, when the inferring restriction condition is a condition that the control mode of the motor 50 changes, the inferring processing is restricted in accordance with the change in the control mode of the motor 50.

[0516] The fifth release condition is that, when the motor 50 is driven by alternating current generated on the basis of power supply electric power supplied from a power supply 60, an integer multiple of a frequency of a voltage of the power supply 60 deviates from an integer multiple or an M / N (M and N are integers) multiple of a rotational frequency of the motor 50.

[0517] The sixth release condition is that the motor drive device 20 has a direct current section 22 that generates direct current corresponding to power supply electric power supplied from a power supply 60, and a conversion section 23 that converts the direct current generated by the direct current section 22 into alternating current through switching operation, and when the motor 50 is driven by the motor drive device 20, the voltage of the direct current section 22 changes from a non-stable state to a stable state,

[0518] The restriction release condition is established when all the conditions included in the restriction release condition are established.

[0519] (Summary of Embodiments)

[0520] As described above, the state inferring apparatus (control device 30) of the embodiments relates to a state inferring apparatus that infers a state of an apparatus 70 having a motor 50. The state inferring apparatus includes a control section 31.

[0521] The control section 31 performs a calculation process in which a characteristic quantity is calculated from a physical quantity obtained from the apparatus 70 within a prescribed period, an inference process in which a state of the apparatus 70 is inferred from the characteristic quantity calculated by the calculation process, and a restriction process in which the inference process is restricted so as to output a preset inference result when a prescribed inference restriction condition is established, the restriction on the inference process is maintained until a prescribed standby release condition is established when a prescribed restriction release condition is established, and the restriction on the inference process is released after the prescribed standby release condition is established.

[0522] The physical quantity is a quantity that varies according to rotation of the motor 50. The characteristic quantity is a quantity that varies according to a state of the apparatus 70. The state of the apparatus 70 includes at least one of an abnormality of the motor 50, a degree of deterioration of the motor 50, an abnormality of a component driven by the motor 50, and a degree of deterioration of the component driven by the motor 50. The inference restriction condition is a condition that has a possibility of occurrence of a false inference in the inference process. The restriction release condition is a condition that can suppress a false inference in the inference process.

[0523] For example, the "likelihood of occurrence of a false inference in the inference processing" in the inference restriction condition is lower than the "likelihood of occurrence of a false inference in the inference processing" in the restriction release condition. Further, the inference restriction condition is that the operation state of the motor 50 or the operation state of a component linked with the motor 50 is not the "preset normal operation state" but a "non-normal operation state in which a characteristic quantity is likely to be changed unexpectedly (noise that becomes a cause of a false inference in the inference processing) compared with a case where the operation state is in the normal operation state". The restriction release condition is the condition that the operation state of the motor 50 or the operation state of a component linked with the motor 50 becomes the above-described "preset normal operation state". Note that the component linked with the motor 50 includes at least one of a "component that drives the motor 50" and a "component that is driven by the motor 50".

[0524] The operation state of the motor 50 is, for example, a state of a rotational speed (or a rotational frequency) of the motor 50, a state of a control mode of the motor 50, or the like. The state of the component that drives the motor 50 is, for example, a state of a voltage of the direct-current portion 22 of the motor drive device 20, or the like. The state of the component that is driven by the motor 50 is, for example, a state of a pressure of a fluid that flows into the compressor CC (or a fluid that flows out of the compressor CC), a state of a temperature of the fluid that flows into the compressor CC (or the fluid that flows out of the compressor CC), or the like.

[0525] In the above-described configuration, when the prescribed inference restriction condition is established, the inference processing is restricted so as to output a preset inference result, whereby it is possible to appropriately suppress a false inference of the state of the device 70. Further, by restricting the inference processing in accordance with establishment of the prescribed restriction release condition, it is possible to appropriately release the restriction of the inference processing.

[0526] Further, in the above-described configuration, when the prescribed restriction release condition is established, the restriction of the inference processing is maintained until the prescribed standby release condition is established, and the restriction of the inference processing is released after the prescribed standby release condition is established. In this way, compared with a case where the restriction of the inference processing is released without waiting for the prescribed standby release condition to be established, it is possible to release the restriction of the inference processing after the characteristic quantity calculated in the calculation processing is stabilized. In this way, it is possible to suppress a false inference of the state of the device 70 after the restriction of the inference processing is released.

[0527] Further, the state inferring method of the embodiment involves a state inferring method that infers a state of an apparatus 70 having a motor 50. The state inferring method includes a calculating step in which a characteristic quantity is calculated from a physical quantity obtained from the apparatus 70 within a prescribed period, an inferring step in which the state of the apparatus 70 is inferred from the characteristic quantity calculated by the calculating step, and a restricting step in which the inferring step is restricted so as to output a preset inferring result when a prescribed inferring restriction condition is satisfied, the restriction on the inferring step is maintained until a prescribed standby release condition is satisfied when a prescribed restriction release condition is satisfied, and the restriction on the inferring step is released after the prescribed standby release condition is satisfied.

[0528] As with the state inferring apparatus, the physical quantity is a quantity that varies in accordance with the rotation of the motor 50. The characteristic quantity is a quantity that varies in accordance with the state of the apparatus 70. The state of the apparatus 70 includes at least one of an abnormality of the motor 50, a degree of deterioration of the motor 50, an abnormality of a component driven by the motor 50, and a degree of deterioration of the component driven by the motor 50. The inferring restriction condition is a condition in which there is a possibility of an erroneous inference occurring in the inferring step. The restriction release condition is a condition in which an erroneous inference can be suppressed in the inferring step.

[0529] In the above-described method, when the prescribed inferring restriction condition is satisfied, the inferring step is restricted so as to output a preset inferring result, whereby an erroneous inference of the state of the apparatus 70 can be appropriately suppressed. Further, by restricting the inferring step in accordance with the satisfaction of the prescribed restriction release condition, the restriction on the inferring step can be appropriately released.

[0530] Further, in the above-described method, when the prescribed restriction release condition is satisfied, the restriction on the inferring step is maintained until the prescribed standby release condition is satisfied, and the restriction on the inferring step is released after the prescribed standby release condition is satisfied. In this way, compared with a case in which the restriction on the inferring step is released without waiting for the prescribed standby release condition to be satisfied, the restriction on the inferring step can be released after the characteristic quantity calculated in the calculating step is stabilized. In this way, an erroneous inference of the state of the apparatus 70 can be suppressed after the restriction on the inferring step is released.

[0531] Note that the restriction release condition can also be a condition in which the rotational speed of the motor 50 changes from a non-stable state to a stable state.

[0532] Further, the apparatus 70 can also include a compressor CC having the motor 50. The restriction release condition can also be a condition in which the pressure of a fluid flowing into the compressor CC or the pressure of a fluid flowing out of the compressor CC changes from a non-stable state to a stable state.

[0533] Further, the device 70 can also include the compressor CC having the motor 50. The restriction release condition can also be a condition that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from the unstable state to the stable state.

[0534] Further, the restriction release condition can be the first condition that "the control mode of the motor 50 changes after the inference processing is restricted" or the second condition that "when the inference restriction condition is the condition that the control mode of the motor 50 changes, the inference processing is restricted in accordance with the change in the control mode of the motor 50".

[0535] Further, the motor 50 can also be driven by alternating current generated based on the power supply electric power supplied from the power supply 60. The restriction release condition can also be a condition that an integer multiple or M / N multiple (M, N are integers) of the rotational frequency of the motor 50 deviates from the vicinity of an integer multiple of the frequency of the voltage of the power supply 60. In this case, the characteristic quantity can also be a frequency component of the M / N multiple of the rotational frequency of the motor 50.

[0536] Further, it can also be that the motor 50 is driven by the motor drive device 20 having the direct current portion 22 that generates direct current corresponding to the power supply electric power supplied from the power supply 60 and the conversion portion 23 that converts the direct current generated by the direct current portion 22 into alternating current through switching operation. The restriction release condition can also be a condition that the voltage of the direct current portion 22 changes from the unstable state to the stable state.

[0537] Further, it can also be that the device 70 includes the compressor CC having the motor 50, and the restriction release condition includes at least two of the first to sixth release conditions, and the restriction release condition is established when the conditions included in the restriction release condition are all established.

[0538] Note that the first release condition is a condition that the rotational speed of the motor 50 changes from the unstable state to the stable state. The second release condition is a condition that the pressure of the fluid flowing into the compressor CC or the pressure of the fluid flowing out of the compressor CC changes from the unstable state to the stable state. The third release condition is a condition that the temperature of the fluid flowing into the compressor CC or the temperature of the fluid flowing out of the compressor CC changes from the unstable state to the stable state.

[0539] The fourth release condition is the first condition or the second condition, the first condition is "the control mode of the motor 50 is changed after the inference processing is limited", and the second condition is "when the inference limit condition is the condition that the control mode of the motor 50 is changed, the inference processing is limited according to the change in the control mode of the motor 50". The fifth release condition is that when the motor 50 is driven by the alternating current generated based on the power supply electric power supplied from the power supply 60, the frequency of the voltage of the power supply 60 deviates from the vicinity of an integer multiple of the rotational frequency of the motor 50 or an integer multiple of M / N (M, N are integers).

[0540] The sixth release condition is that the motor drive device 20 has a direct current portion 22 that generates direct current corresponding to the power supply electric power supplied from the power supply 60 and a conversion portion 23 that converts the direct current generated by the direct current portion 22 into alternating current by switching operation, and when the motor 50 is driven by the motor drive device 20, the voltage of the direct current portion 22 is changed from a non-stable state to a stable state.

[0541] In addition, the physical quantity can also be any one of the current supplied to the motor 50, the voltage applied to the motor 50, the rotational speed of the motor 50, the vibration of the device 70, and the sound of the device 70.

[0542] In addition, the characteristic quantity can also be a frequency component.

[0543] Note that the characteristic quantity is a quantity calculated from the physical quantity within a specified period. For example, the characteristic quantity can also be a quantity indicating the change in the physical quantity within a specified period over time. The above-mentioned characteristic quantity can be obtained by sampling the physical quantity within a specified period at a specified sampling period. In addition, the characteristic quantity can also be a quantity that changes according to the change in the physical quantity within a specified period over time.

[0544] In addition, the inference limit condition can also include the following condition: the rotational speed of the motor 50 is a certain rotational speed, and the pressure of the fluid flowing into the compressor CC and the pressure of the fluid flowing out of the compressor CC are both certain pressures.

[0545] -Industrial applicability-

[0546] As described above, the present disclosure is useful as a state inference technology.

[0547] -Symbol explanation-

[0548] 10 Drive system

[0549] 20 Motor drive device

[0550] 21 AC / DC converter

[0551] 22 Direct current portion

[0552] 23 AC / DC converter (conversion unit)

[0553] 30 control device (state inferring device)

[0554] 31 control unit

[0555] 41 phase current detecting unit

[0556] 42 electric angle frequency detecting unit

[0557] 50 motor

[0558] 60 power supply

[0559] 70 apparatus

[0560] CC compressor

[0561] RR refrigeration system

[0562] RR1 refrigerant circuit

[0563] FF fan system

[0564] FF1 fan

Claims

1. A state inference device for inferring the state of a device (70) having a motor (50), characterized in that: The state inference device includes a control unit (31), which performs calculation processing, inference processing, and restriction processing. In the calculation process, characteristic quantities are calculated based on physical quantities obtained from the device (70) within a specified period. In the inference process, the state of the device (70) is inferred based on the feature quantities calculated by the calculation process. In the restriction process, when a specified inference restriction condition is met, the inference process is restricted to output a preset inference result. When a specified restriction release condition is met, the restriction on the inference process is maintained until a specified standby release condition is met. After the specified standby release condition is met, the restriction on the inference process is released. The physical quantity is a quantity that varies according to the rotation of the motor (50). The characteristic quantity is a quantity that varies according to the state of the device (70). The state of the device (70) includes at least one of the following: an abnormality of the motor (50), the degree of degradation of the motor (50), an abnormality of the components driven by the motor (50), and the degree of degradation of the components driven by the motor (50). The inference constraint is a condition that allows for the possibility of incorrect inference during the inference process. The restriction removal condition is a condition that can suppress erroneous inferences in the inference process.

2. The state inference device according to claim 1, characterized in that: The condition for lifting the restriction is that the rotational speed of the motor (50) changes from an unstable state to a stable state.

3. The state inference device according to claim 1, characterized in that: The device (70) includes a compressor (CC) having the electric motor (50). The condition for lifting the restriction is that the pressure of the fluid flowing into the compressor (CC) or the pressure of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state.

4. The state inference device according to claim 1, characterized in that: The device (70) includes a compressor (CC) having the electric motor (50). The condition for lifting the restriction is that the temperature of the fluid flowing into the compressor (CC) or the temperature of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state.

5. The state inference device according to claim 1, characterized in that: The restriction release condition is either a first condition or a second condition. The first condition is that the control mode of the motor (50) changes after the inference process is restricted. The second condition is that when the inference restriction condition is that the control mode of the motor (50) changes, the inference process is restricted according to the change in the control mode of the motor (50).

6. The state inference device according to claim 1, characterized in that: The motor (50) is driven by alternating current, which is generated based on power supplied from the power source (60). The restriction release condition is that the frequency of the motor (50) is an integer multiple or M / N times that of the frequency of the power supply (60) voltage deviating from the frequency of the motor (50) voltage, where M and N are integers.

7. The state inference device according to claim 1, characterized in that: The electric motor (50) is driven by a motor drive device (20), which has a DC section (22) and a conversion section (23). The DC section (22) generates DC power corresponding to the power supplied from the power source (60), and the conversion section (23) converts the DC power generated by the DC section (22) into AC power through a switching operation. The restriction release condition is the condition that the voltage of the DC section (22) changes from an unstable state to a stable state.

8. The state inference device according to claim 1, characterized in that: The device (70) includes a compressor (CC) having the electric motor (50). The conditions for lifting the restriction include at least two of the following: a first condition, a second condition, a third condition, a fourth condition, a fifth condition, and a sixth condition. The first release condition is: the speed of the motor (50) changes from an unstable state to a stable state; The second release condition is: the pressure of the fluid flowing into the compressor (CC) or the pressure of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state; The third release condition is: the temperature of the fluid flowing into the compressor (CC) or the temperature of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state; The fourth release condition is either the first condition or the second condition. The first condition is that the control mode of the motor (50) changes after the inference process is restricted. The second condition is that when the inference restriction condition is that the control mode of the motor (50) changes, the inference process is restricted according to the change in the control mode of the motor (50). The fifth release condition is: when the motor (50) is driven by AC power generated based on the power supplied from the power source (60), the rotation frequency of the motor (50) is an integer multiple or M / N multiple that deviates from the frequency of the voltage of the power source (60) by an integer multiple, where M and N are integers; The sixth release condition is: the motor drive device (20) has a DC section (22) and a conversion section (23). The DC section (22) generates DC power corresponding to the power supplied from the power source (60). The conversion section (23) converts the DC power generated by the DC section (22) into AC power through a switching operation. When the motor (50) is driven by the motor drive device (20), the voltage of the DC section (22) changes from an unstable state to a stable state. The restriction is lifted when all of the conditions included in the restriction lifting condition are met.

9. The state inference apparatus according to any one of claims 1 to 8, characterized in that: The physical quantity is any one of the current supplied to the motor (50), the voltage applied to the motor (50), the rotational speed of the motor (50), the vibration of the device (70), and the sound of the device (70).

10. The state inference apparatus according to any one of claims 1 to 9, characterized in that: The characteristic quantity is the frequency component.

11. The state inference device according to claim 3 or 4, characterized in that: The inference constraints include the following conditions: the rotational speed of the motor (50) is a specific speed, and the pressure of the fluid flowing into the compressor (CC) and the pressure of the fluid flowing out of the compressor (CC) are specific pressures.

12. A drive system comprising a motor drive unit (20) and a state inference device, the motor drive unit (20) driving a motor (50) mounted on a device (70), the state inference device inferring the state of the device (70), characterized in that: The state inference device is the state inference device according to any one of claims 1 to 11.

13. A refrigeration system comprising a refrigerant circuit (RR1) and a state inference device, said refrigerant circuit (RR1) comprising a compressor (CC) having an electric motor (50), characterized in that: The state inference device is the state inference device according to any one of claims 1 to 11, which infers the state of the refrigeration system.

14. A fan system comprising a fan (FF1), a motor (50), and a state inference device, wherein the motor (50) drives the fan (FF1), characterized in that: The state inference device is the state inference device according to any one of claims 1, 2, 5 to 7, which infers the state of the fan system.

15. A state inference method for inferring the state of a device (70) having a motor (50), characterized in that: The state inference method includes a calculation step, an inference step, and a constraint step. In the calculation step, the characteristic quantity is calculated based on the physical quantity obtained from the device (70) within a specified period. In the inference step, the state of the device (70) is inferred based on the feature quantities calculated by the calculation step. In the limiting step, when the specified inference limiting condition is met, the inference step is limited to output a preset inference result. When the specified limiting release condition is met, the limitation on the inference step is maintained until the specified standby release condition is met. After the specified standby release condition is met, the limitation on the inference step is released. The physical quantity is a quantity that varies according to the rotation of the motor (50). The characteristic quantity is a quantity that varies according to the state of the device (70). The state of the device (70) includes at least one of the following: an abnormality of the motor (50), the degree of degradation of the motor (50), an abnormality of the components driven by the motor (50), and the degree of degradation of the components driven by the motor (50). The inference constraint is a condition that allows for the possibility of incorrect inference during the inference step. The restriction removal condition is a condition that can suppress erroneous inferences in the inference step.

16. The state inference method according to claim 15, characterized in that: The condition for lifting the restriction is that the rotational speed of the motor (50) changes from an unstable state to a stable state.

17. The state inference method according to claim 15, characterized in that: The device (70) includes a compressor (CC) having the electric motor (50). The condition for lifting the restriction is that the pressure of the fluid flowing into the compressor (CC) or the pressure of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state.

18. The state inference method according to claim 15, characterized in that: The device (70) includes a compressor (CC) having the electric motor (50). The condition for lifting the restriction is that the temperature of the fluid flowing into the compressor (CC) or the temperature of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state.

19. The state inference method according to claim 15, characterized in that: The restriction release condition is either a first condition or a second condition. The first condition is that the control mode of the motor (50) changes after the inference step is restricted. The second condition is that when the inference restriction condition is that the control mode of the motor (50) changes, the inference step is restricted according to the change in the control mode of the motor (50).

20. The state inference method according to claim 15, characterized in that: The motor (50) is driven by alternating current, which is generated based on power supplied from the power source (60). The restriction release condition is that the frequency of the motor (50) is an integer multiple or M / N multiple of the frequency of the voltage of the power supply (60) that deviates from the frequency of the power supply (60), where M and N are integers.

21. The state inference method according to claim 15, characterized in that: The electric motor (50) is driven by a motor drive device (20), which has a DC section (22) and a conversion section (23). The DC section (22) generates DC power corresponding to the power supplied from the power source (60), and the conversion section (23) converts the DC power generated by the DC section (22) into AC power through a switching operation. The restriction release condition is the condition that the voltage of the DC section (22) changes from an unstable state to a stable state.

22. The state inference method according to claim 15, characterized in that: The device (70) includes a compressor (CC) having the electric motor (50). The conditions for lifting the restriction include at least two of the following: a first condition, a second condition, a third condition, a fourth condition, a fifth condition, and a sixth condition. The first release condition is: the speed of the motor (50) changes from an unstable state to a stable state; The second release condition is: the pressure of the fluid flowing into the compressor (CC) or the pressure of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state; The third release condition is: the temperature of the fluid flowing into the compressor (CC) or the temperature of the fluid flowing out of the compressor (CC) changes from an unstable state to a stable state; The fourth release condition is either the first condition or the second condition. The first condition is that the control mode of the motor (50) changes after the inference step is restricted. The second condition is that when the inference restriction condition is that the control mode of the motor (50) changes, the inference step is restricted according to the change in the control mode of the motor (50). The fifth release condition is: when the motor (50) is driven by AC power generated based on the power supplied from the power source (60), the rotation frequency of the motor (50) is an integer multiple or M / N multiple that deviates from the frequency of the voltage of the power source (60) by an integer multiple, where M and N are integers; The sixth release condition is: the motor drive device (20) has a DC section (22) and a conversion section (23). The DC section (22) generates DC power corresponding to the power supplied from the power source (60). The conversion section (23) converts the DC power generated by the DC section (22) into AC power through a switching operation. When the motor (50) is driven by the motor drive device (20), the voltage of the DC section (22) changes from an unstable state to a stable state. The restriction is lifted when all of the conditions included in the restriction lifting condition are met.

23. A state inference program, characterized in that: It enables a computer to execute the state inference method as described in any one of claims 15 to 22.

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