Diagnostic device, power conversion device, diagnostic method, and program

Abstract

To provide a technique capable of diagnosing the degree of deterioration of an AC motor.SOLUTION: A control circuit 70 of a power conversion device 100 according to an embodiment includes: a diagnostic information acquisition unit 701 that acquires information about an electrical physical quantity representing a driving state of an electrical motor EM; a feature quantity acquisition unit 704 that acquires a feature quantity related to temporal changes due to harmonic components of the electrical physical quantity representing the driving state of the electrical motor EM; and a diagnostic unit 706 that diagnoses degree of deterioration of the electrical motor EM based on the feature quantity.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to diagnostic devices and the like. [Background technology]

[0002] BACKGROUND ART Conventionally, techniques for diagnosing abnormalities in AC motors are known (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-114084 [Patent Document 2] International Publication No. 2014 / 156386 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the above-described technique can detect the occurrence of an abnormality in the AC motor, it cannot detect the degree of deterioration of the AC motor (the degree of progress of deterioration).

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a technique capable of diagnosing the degree of deterioration of an AC motor. [Means for solving the problem]

[0006] In order to achieve the above object, in one embodiment of the present disclosure, a first information acquisition unit that acquires information about an electrical physical quantity that represents a driving state of the AC motor; Peak in the time change of the electrical physical quantity Peaks and valleys as a peak detection unit for detecting Detected by the peak detection unit Peaks and valleys Based on the historical value of By waveform counting method, a cycle detection unit that detects a cycle of a time change in the electrical physical quantity; The cycle detection unit detects time series data of the electrical physical quantity for a predetermined period. Multiple cycle Each of The variation range of the electrical physical quantity in , over the multiple cycles a feature acquisition unit that acquires a feature relating to a time change of the electrical physical quantity based on the entire history; a diagnosis unit that diagnoses a degree of deterioration of the AC motor based on the feature amount, A diagnostic device is provided.

[0007] In another embodiment of the present disclosure, A power conversion device that supplies drive power to the AC motor based on power input from an external source, a diagnostic device as described above; A power converter is provided.

[0008] In still another embodiment of the present disclosure, a first information acquisition step in which the diagnostic device acquires information about an electrical physical quantity that represents a driving state of the AC motor; The diagnostic device detects a peak in the time change of the electrical physical quantity. Peaks and valleys as a peak detection step of detecting The diagnostic device detects the peaks detected in the peak detection step. Peaks and valleys Based on the historical value of By waveform counting method, a cycle detection step of detecting a cycle of a time change of the electrical physical quantity; The diagnostic device detects the cycle of the time series data of the electrical physical quantity for a predetermined period in the cycle detection step. Multiple cycle Each of The variation range of the electrical physical quantity in , over the multiple cycles a feature acquisition step of acquiring a feature relating to a time change of the electrical physical quantity based on the entire history; a diagnosing step in which the diagnosing device diagnoses a degree of deterioration of the AC motor based on the feature amount, A diagnostic method is provided.

[0009] In still another embodiment of the present disclosure, For diagnostic equipment, a first information acquisition step of acquiring information about an electrical physical quantity that represents a driving state of the AC motor; Peak in the time change of the electrical physical quantity Peaks and valleys as a peak detection step of detecting Detected in the peak detection step Peaks and valleys Based on the historical value of By waveform counting method, a cycle detection step of detecting a cycle of a time change of the electrical physical quantity; The time series data of the electrical physical quantity for a predetermined period is detected in the cycle detection step. Multiple cycle Each of The variation range of the electrical physical quantity in , over the multiple cycles a feature acquisition step of acquiring a feature relating to a time change of the electrical physical quantity based on the entire history; a diagnosis step of diagnosing a degree of deterioration of the AC motor based on the feature amount; Programs are offered. [Effects of the Invention]

[0010] According to the above-described embodiment, it is possible to diagnose the degree of deterioration of an AC motor. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 illustrates an example of a hardware configuration of a diagnostic system. [Figure 2] FIG. 2 illustrates an example of a hardware configuration of a management apparatus. [Figure 3] 2 is a functional block diagram showing an example of a functional configuration related to a diagnostic function of a power conversion device (control circuit). FIG. [Figure 4] 10A and 10B are diagrams illustrating an example of results of waveform counting processing and feature amount acquisition processing. [Figure 5] FIG. 10 is a diagram showing an example of the distribution of the number of occurrences of cycle change values when an abnormality occurs due to deterioration of the electric motor. [Figure 6] 1 is a main flowchart illustrating an example of a diagnostic process. [Figure 7] 10 is a sub-flowchart illustrating an example of a diagnostic process. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment will be described with reference to the drawings.

[0013] [Hardware configuration of diagnostic system] The hardware configuration of a diagnostic system 1 according to this embodiment will be described with reference to FIGS.

[0014] Fig. 1 is a diagram showing an example of the hardware configuration of a diagnostic system 1 according to this embodiment. Fig. 2 is a diagram showing an example of the hardware configuration of a management device 200 according to this embodiment.

[0015] The hardware configuration of the terminal device 300 is the same as that of the management device 200, and therefore illustrations and detailed explanations thereof will be omitted.

[0016] As shown in FIG. 1, the diagnostic system 1 includes an electric motor EM, a power conversion device 100, a management device 200, and a terminal device 300.

[0017] The electric motor EM (an example of an AC electric motor) drives, for example, production equipment or machinery installed in a factory. The electric motor EM is, for example, an induction motor.

[0018] The power conversion device 100 converts three-phase AC power (e.g., R phase, S phase, and T phase) input from a commercial power source PS into three-phase AC power (e.g., U phase, V phase, and W phase) having a predetermined voltage and a predetermined frequency, and drives an electric motor EM.

[0019] The power conversion device 100 includes a rectifier circuit 10, a smoothing circuit 20, an inverter circuit 30, a current sensor 40, a voltage sensor 50, a gate drive circuit 60, a control circuit 70, a display unit 80, and a communication unit 90.

[0020] The rectifier circuit 10 is configured to rectify three-phase AC power input from a commercial power supply PS and output DC power. The positive and negative output terminals of the rectifier circuit 10 are connected to one end of a positive line PL and a negative line NL, respectively, and the rectifier circuit 10 can output DC power to the smoothing circuit 20 through the positive line PL and the negative line NL. The rectifier circuit 10 is a bridge-type full-wave rectifier circuit that includes, for example, six semiconductor diodes SD and has three sets of two-series connected semiconductor diodes SD constituting upper and lower arms connected in parallel.

[0021] The smoothing circuit 20 suppresses and smoothes pulsations in the DC power output from the rectifier circuit 10 and the DC power regenerated from the inverter circuit 30 .

[0022] The smoothing circuit 20 includes, for example, a smoothing capacitor 21 .

[0023] The smoothing capacitor 21 may be provided in parallel with the rectifier circuit 10 and the inverter circuit 30 in a path connecting the positive line PL and the negative line NL.

[0024] The smoothing capacitor 21 smoothes the DC power output from the rectifier circuit 10 and the DC power output (regenerated) from the inverter circuit 30 while repeatedly charging and discharging as appropriate.

[0025] There may be one smoothing capacitor 21. Alternatively, a plurality of smoothing capacitors 21 may be arranged, and the plurality of smoothing capacitors 21 may be connected in parallel or in series between the positive line PL and the negative line NL. Alternatively, the plurality of smoothing capacitors 21 may be configured in such a way that a series connection of two or more smoothing capacitors is connected in parallel between the positive line PL and the negative line NL.

[0026] Furthermore, the smoothing circuit 20 may include, for example, a reactor.

[0027] The reactor may be provided, for example, on the positive line PL between the rectifier circuit 10 and the smoothing capacitor 21 (specifically, the branch point from the path where the smoothing capacitor 21 is arranged).

[0028] The reactor smoothes the DC power output from the rectifier circuit 10 and the DC power output (regenerated) from the inverter circuit 30 while generating a voltage that appropriately prevents changes in the current.

[0029] The inverter circuit 30 has positive and negative input terminals connected to the other ends of the positive line PL and the negative line NL. The inverter circuit 30 converts the DC power supplied from the smoothing circuit 20 into three-phase AC power (e.g., U phase, V phase, and W phase) having a predetermined frequency and a predetermined voltage through the switching operation of the semiconductor switch SW, and outputs the AC power to the electric motor EM. The semiconductor switch SW may be, for example, an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET) made of silicon (Si). The semiconductor switch SW may also be, for example, a semiconductor element using a wide bandgap semiconductor such as silicon carbide (SiC) or gallium nitride (GaN).

[0030] The inverter circuit 30 may include, for example, six semiconductor switches SW, and may be configured to include a bridge circuit in which three sets of series-connected elements (switch legs) of two semiconductor switches SW constituting upper and lower arms are connected in parallel between a positive line PL and a negative line NL. The inverter circuit 30 may output three-phase AC power through three output lines drawn from the connection points of the three sets of upper and lower arms. A free-wheeling diode may be connected in parallel to each of the six semiconductor switches SW.

[0031] The current sensor 40 detects the current in each of the three-phase (three wires) output lines of the power conversion device 100, i.e., the current in each of the three phases of the electric motor EM. The current sensor 40 outputs a signal corresponding to the current value in each of the three phases of the electric motor EM, and the output signal of the current sensor 40 is taken into the control circuit 70.

[0032] The current sensor 40 may detect currents of only any two phases of the three-phase output lines of the power conversion device 100. In this case, the control circuit 70 may obtain (calculate) the current value of the remaining phase from the detected values of the two-phase currents. The control circuit 70 may also obtain (calculate) the current values of the three-phase output lines of the power conversion device 100 based on, for example, the current values of the DC links (positive line PL and negative line NL) and the switching pattern of the semiconductor switch SW. In this case, the control circuit 70 may obtain (calculate) the current value of the DC link based on the output of the voltage sensor 50.

[0033] The voltage sensor 50 detects the voltage (DC link voltage) between the positive line PL and the negative line NL of the power conversion device 100. The voltage sensor 50 outputs a signal corresponding to the voltage value between the positive line PL and the negative line NL, and the output signal of the voltage sensor 50 is taken into the control circuit 70.

[0034] The gate drive circuit 60 outputs drive signals for switching (ON / OFF) the six semiconductor switches SW of the inverter circuit 30 to the gate terminals of the six semiconductor switches SW under the control of the control circuit 70.

[0035] The control circuit 70 (an example of a diagnostic device) controls the power conversion device 100.

[0036] The functions of the control circuit 70 may be realized by any hardware or any combination of hardware and software, etc. For example, as shown in Fig. 1, the control circuit 70 is mainly configured with a computer including an auxiliary storage device 71, a memory device 72, a CPU (Central Processing Unit) 73, and an interface device 74, which are connected to each other by a bus B1.

[0037] The auxiliary storage device 71 is a non-volatile storage means, and stores, for example, various installed programs and data required for various processes. The auxiliary storage device 71 is, for example, a flash memory.

[0038] When an instruction to start a program is given, the memory device 72 reads and stores the program from the auxiliary storage device 71. The memory device 72 is, for example, an SRAM (Static Random Access Memory).

[0039] The CPU 73 executes various programs loaded from the auxiliary storage device 71 to the memory device 72, and implements various functions related to the power conversion device 100 according to the programs. As a result, the control circuit 70 can perform various controls by loading the programs installed in the auxiliary storage device 71 into the memory device 72 and having the CPU 73 execute the programs.

[0040] The interface device 74 is used as an interface for communicatively connecting the control circuit 70 to an external device. The interface device 74 may have multiple types of interface devices depending on the communication method between the control circuit 70 and the connected device. This allows the control circuit 70 to receive external data and signals and output (transmit) data and signals to the outside through the interface device 74.

[0041] The control circuit 70 controls the inverter circuit 30 so that the electric motor EM operates under predetermined operating conditions. Specifically, the control circuit 70 may output a control signal to the gate drive circuit 60, thereby outputting a drive signal such as a PWM (Pulse Width Modulation) signal to the semiconductor switch SW via the gate drive circuit 60, thereby controlling the inverter circuit 30.

[0042] The control circuit 70 also performs processing related to a diagnostic function for, for example, the deterioration and lifespan of the electric motor EM. Deterioration of the electric motor EM includes, for example, insulation deterioration such as a layer short in the coil. The diagnostic function will be described in detail later.

[0043] The functions of the control circuit 70 may be distributed and realized by a plurality of control circuits mounted on the power conversion device 100. For example, the control function of the inverter circuit 30 and the above-mentioned diagnostic function may be realized by different control circuits. Furthermore, some of the functions of the control circuit 70 may be transferred to the management device 200 or the terminal device 300. For example, the above-mentioned diagnostic function may be transferred to the management device 200 or the terminal device 300 (both are examples of diagnostic devices). In this case, data required for the diagnostic function (for example, detection data of the current sensor 40, etc.) is transmitted (uploaded) to the management device 200 or the terminal device 300 via the communication unit 90.

[0044] The display unit 80 displays information about the power conversion device 100 to a user (for example, a worker at a factory where production equipment or machinery driven by the electric motor EM is installed) under the control of the control circuit 70. The display unit 80 includes, for example, a warning light, an electronic bulletin board, a liquid crystal display, an organic EL (Electroluminescence) display, etc.

[0045] The communication unit 90 communicates with devices external to the power conversion device 100 via a predetermined communication line.

[0046] The predetermined communication line may be, for example, a one-to-one communication line. The predetermined communication line may also include, for example, a local area network (LAN) such as a field network established within a facility (factory) where production equipment, machinery, etc. driven by the electric motor EM are installed. The local network may be wired, wireless, or may include both. The predetermined communication line may also include, for example, a wide area network (WAN) outside the facility (factory) where production equipment, machinery, etc. driven by the electric motor EM are installed. Wide area networks may include, for example, a mobile communication network terminated at a base station, a satellite communication network using a communication satellite, the Internet, etc. The predetermined communication line may also include, for example, a short-range communication line based on a predetermined wireless communication standard such as Bluetooth (registered trademark) or WiFi.

[0047] The function of the communication unit 90 may be incorporated into the control circuit 70 as a function of the interface device 74 .

[0048] The management device 200 is provided outside the power conversion device 100, and serves as a higher-level device of the power conversion device 100 to manage (monitor) the power conversion device 100 and the electric motor EM.

[0049] The functions of the management device 200 are realized by any hardware or any combination of hardware and software, etc. For example, as shown in Fig. 2, the management device 200 includes an external interface 201, an auxiliary storage device 202, a memory device 203, a CPU 204, a communication interface 206, an input device 207, and a display device 208, which are connected to one another by a bus B2.

[0050] The external interface 201 functions as an interface for reading data from the recording medium 201A and writing data to the recording medium 201A. Examples of the recording medium 201A include a flexible disk, a CD (Compact Disc), a DVD (Digital Versatile Disc), a BD (Blu-ray (registered trademark) Disc), an SD memory card, a USB memory, etc. This allows the management device 200 to read various data used in processing through the recording medium 201A, store the data in the auxiliary storage device 202, and install programs that realize various functions.

[0051] The management device 200 may obtain various data and programs from an external computer via the communication interface 206.

[0052] The auxiliary storage device 202 stores various installed programs as well as files and data required for various processes. The auxiliary storage device 202 includes, for example, a hard disk drive (HDD), a solid state drive (SSD), a flash memory, etc.

[0053] When an instruction to start a program is received, the memory device 203 reads and stores the program from the auxiliary storage device 202. The memory device 203 includes, for example, a dynamic random access memory (DRAM) or an SRAM.

[0054] The CPU 204 executes various programs loaded from the auxiliary storage device 202 to the memory device 203, and realizes various functions related to the management device 200 in accordance with the programs.

[0055] The high-speed arithmetic unit 205 performs arithmetic processing at a relatively high speed in cooperation with the CPU 204. The high-speed arithmetic unit 205 includes, for example, a graphics processing unit (GPU), an application specific integrated circuit (ASIC), or a field-programmable gate array (FPGA).

[0056] The high speed calculation device 205 may be omitted depending on the required calculation processing speed.

[0057] The communication interface 206 is used as an interface for communicatively connecting with an external device. This allows the management device 200 to communicate with an external device such as the power conversion device 100 through the communication interface 206. The communication interface 206 may have multiple types of communication interfaces depending on the communication method between the connected device and the like.

[0058] The input device 207 receives various inputs from a user. For example, the input device 207 includes an input device (remote control device) for an operator to perform remote control.

[0059] The input device 207 includes, for example, an operation input device that accepts mechanical operation input from a user. The operation input device includes, for example, a button, a toggle, a lever, etc. The operation input device also includes, for example, a touch panel mounted on the display device 208, a touch pad provided separately from the display device 208, etc.

[0060] The input device 207 also includes, for example, a voice input device capable of receiving voice input from the user. The voice input device includes, for example, a microphone capable of collecting the user's voice.

[0061] The input device 207 includes, for example, a gesture input device capable of receiving a gesture input from a user. The gesture input device includes, for example, a camera capable of capturing an image of a user's gesture.

[0062] The input device 207 includes, for example, a biometric input device capable of accepting biometric input from a user. The biometric input device includes, for example, a camera capable of acquiring image data containing information about a user's fingerprint or iris.

[0063] The display device 208 displays an information screen or an operation screen for the user. For example, the display device 208 includes the above-mentioned remote control display device. The display device 208 is, for example, a liquid crystal display or an organic EL display.

[0064] The management device 200, for example, acquires data relating to the states of the power conversion device 100 and the electric motor EM from the power conversion device 100, and monitors the states of the power conversion device 100 and the electric motor EM. The management device 200 also, for example, outputs a control signal to the power conversion device 100, and controls the power conversion device 100 and the electric motor EM. The management device 200 also provides information relating to the power conversion device 100 and the electric motor EM to users such as workers and managers, and receives input from users and transmits the information to the power conversion device 100.

[0065] Furthermore, the management device 200 may perform a diagnosis regarding the deterioration and lifespan of the electric motor EM in place of the power conversion device 100 (control circuit 70), as described above.

[0066] The management device 200 is, for example, an edge controller such as a programmable logic controller (PLC) that manages field devices including the power conversion device 100 in a factory or the like where machinery and production equipment driven by the electric motor EM are installed. The management device 200 is, for example, a management terminal device. The management terminal device may be, for example, a stationary computer terminal such as a desktop personal computer (PC) installed in an office of the factory or the like. The management terminal device may also be, for example, a portable terminal device (mobile terminal) that can be carried by a manager or worker of the factory or the like, such as a tablet terminal, smartphone, or laptop PC. The management device 200 is, for example, a server device. The server device may be, for example, an on-premise server or a cloud server installed remotely from a factory or the like where production equipment and machinery driven by the electric motor EM are installed. The server device may also be an edge server installed on the premises of a factory or the like where production equipment and machinery electrically driven by the electric motor EM are installed, or in a nearby facility.

[0067] The terminal device 300 is a user terminal provided outside the power conversion device 100 and used by a user of the diagnostic system 1. The user of the diagnostic system 1 is an operator, manager, or the like of a factory in which production equipment or machinery driven by the electric motor EM is installed. The terminal device 300 provides the user with various information related to the power conversion device 100 and the electric motor EM, accepts various inputs from the user, and transmits the information to the power conversion device 100, for example.

[0068] The terminal device 300 may be, for example, a stationary terminal device such as a desktop PC, or may be, for example, a portable terminal device (mobile terminal) such as a smartphone, a tablet terminal, or a laptop PC.

[0069] [Diagnostic function configuration] Next, with reference to FIG. 3, a functional configuration relating to the diagnostic function of the power conversion device 100 (control circuit 70) will be described.

[0070] FIG. 3 is a functional block diagram showing an example of a functional configuration related to the diagnostic function of the power conversion device 100 (control circuit 70).

[0071] 3, the control circuit 70 includes, as functional units related to the diagnostic function, a diagnostic information acquisition unit 701, a peak detection unit 702, a waveform counting unit 703, a feature amount acquisition unit 704, an operating time acquisition unit 705, a diagnosis unit 706, and a notification unit 707. The functions of the diagnostic information acquisition unit 701, the peak detection unit 702, the waveform counting unit 703, the feature amount acquisition unit 704, the operating time acquisition unit 705, the diagnosis unit 706, and the notification unit 707 are realized, for example, by loading a program installed in the auxiliary storage device 71 into the memory device 72 and executing it by the CPU 73.

[0072] The diagnostic information acquisition unit 701 acquires information for diagnosing the deterioration and lifespan of the electric motor EM (hereinafter referred to as "diagnostic information").

[0073] The diagnostic information acquisition unit 701 (an example of a first information acquisition unit) acquires, as diagnostic information, information relating to an electrical physical quantity (hereinafter referred to as "diagnostic physical quantity") that indicates the driving state of the electric motor EM.

[0074] The information about the diagnostic physical quantity is, for example, information about the current of the electric motor EM. That is, the diagnostic physical quantity may be the current of the electric motor EM. The information about the current of the electric motor EM is acquired based on the output of the current sensor 40. The information about the current of the electric motor EM is, for example, information about the phase current of the electric motor EM. Furthermore, the information about the current of the electric motor EM may be, for example, information about two-phase AC currents (α-axis current and β-axis current) in a stationary coordinate system acquired by αβ transformation based on the three-phase phase currents of the electric motor EM. Furthermore, the information about the current of the electric motor EM may be, for example, information about two-phase AC currents (d-axis current and q-axis current) in a fixed coordinate system acquired by dq transformation based on the two-phase AC currents in the stationary coordinate system.

[0075] Furthermore, the information about the diagnostic physical quantity may be, for example, information about the voltage of the electric motor EM. That is, the diagnostic physical quantity may be the voltage of the electric motor EM. The information about the voltage of the electric motor EM is acquired, for example, based on a command value for the three-phase output voltage of the inverter circuit 30, which is generated by the control function of the inverter circuit 30 of the control circuit 70. The information about the voltage of the electric motor EM is acquired, for example, based on detection information about the three-phase phase voltages and inter-phase voltages of the power conversion device 100. In this case, the power conversion device 100 is equipped with a voltage sensor that detects the three-phase phase voltages and inter-phase voltages of the power conversion device 100. The information about the voltage of the electric motor EM is, for example, information about the three-phase phase voltages of the electric motor EM. The information about the voltage of the electric motor EM may be, for example, information about two-phase AC voltages (α-axis voltage and β-axis voltage) in a stationary coordinate system, which is acquired by αβ transformation based on the three-phase phase voltages of the electric motor EM. Furthermore, the information about the voltage of the electric motor EM may be, for example, information about the two-phase AC voltage (d-axis voltage and q-axis voltage) in a stationary coordinate system, obtained by dq transformation based on the two-phase AC voltage in a stationary coordinate system.

[0076] Furthermore, the information on the diagnostic physical quantity may be, for example, information on the electric power of the electric motor EM. That is, the diagnostic physical quantity may be the electric power of the electric motor EM. The information on the electric power of the electric motor EM is acquired, for example, based on information on the current of the electric motor EM and information on the voltage of the electric motor. The information on the electric power of the electric motor EM is, for example, information on at least one of the active power and the reactive power of the electric motor EM.

[0077] Furthermore, the diagnostic information acquisition unit 701 (an example of a second information acquisition unit) may acquire information on the rotation speed of the electric motor EM as diagnostic information in conjunction with (synchronization with) acquisition of information on the diagnostic physical quantity.

[0078] Information about the rotation speed of the electric motor EM is acquired, for example, based on detected information about the rotation speed of the electric motor EM. In this case, the electric motor EM is equipped with a sensor (for example, an encoder) that detects the rotation speed of the electric motor EM. Furthermore, information about the rotation speed of the electric motor EM may be calculated (estimated), for example, based on the output of the current sensor 40, i.e., the detected value of the phase current of the electric motor EM.

[0079] Furthermore, the diagnostic information acquiring unit 701 may correct the information on the diagnostic physical quantity based on the rotational speed information and acquire information on the corrected diagnostic physical quantity (hereinafter, "diagnostic corrected physical quantity"). Specifically, the diagnostic information acquiring unit 701 may correct the diagnostic physical quantity information based on the rotational speed information so that the diagnostic physical quantity becomes a value corresponding to the reference rotational speed of the electric motor EM, and acquire information on the diagnostic corrected physical quantity. This is because the diagnostic physical quantity changes depending on the rotational state of the electric motor EM. This allows the control circuit 70 to suppress the influence of the rotational speed of the electric motor EM on the diagnostic physical quantity, thereby enabling more accurate diagnosis of the deterioration level of the electric motor EM. For example, the diagnostic information acquiring unit 701 may correct the information on the diagnostic physical quantity based on the rotational speed information using table data, a map, a relational expression, or the like that indicates the correlation between the diagnostic physical quantity and the rotational speed of the electric motor EM, and acquire information on the diagnostic corrected physical quantity. Table data, maps, relational expressions, etc. that represent the correlation between the diagnostic physical quantities and the rotational speed of the electric motor EM may be determined in advance through, for example, experiments or simulations related to the electric motor EM.

[0080] The peak detecting unit 702 detects peak portions, i.e., crests or valleys, of components corresponding to harmonics in the time-series data (waveform data) of the diagnostic physical quantity or the corrected diagnostic physical quantity for a predetermined period, and detects the values (hereinafter referred to as "peak values") Aj. The subscript j indicates the order of appearance of peak values in the time series, starting from the smallest. The peak detecting unit 702 may, for example, apply various filters to the time-series data of the diagnostic physical quantity or the corrected diagnostic physical quantity to remove fundamental wave components or extract specific harmonic components (e.g., second-order harmonic components). In this way, the peak detecting unit 702 can extract components corresponding to harmonics in the time-series data of the diagnostic physical quantity or the corrected diagnostic physical quantity. However, when the diagnostic physical quantity or the corrected diagnostic physical quantity is a two-phase AC current or voltage in a rotating coordinate system, the peak detecting unit 702 can use the current (d-axis current and q-axis current) or voltage (d-axis voltage and q-axis voltage) as they are. This is because the fundamental wave components of the phase current and the phase voltage are converted to DC by the dq transformation, and as a result, only the components corresponding to distortion (harmonic components) appear as changes in the two-phase AC current and voltage in the rotating coordinate system. Specifically, the peak detection unit 702 monitors the temporal changes in the components corresponding to harmonics in the time-series data (waveform data) of the diagnostic physical quantity or the diagnostic corrected physical quantity for a predetermined period, and detects the value of the change point (peak) from an increase to a decrease or the change point (trough) from a decrease to an increase as the peak value Aj.

[0081] The waveform counting unit 703 (an example of a cycle detection unit) counts (detects) cycles of change due to components corresponding to harmonics in the time change of the diagnostic physical quantity or the diagnostic corrected physical quantity based on the time-series data of the peak value Aj. The detected cycles may include, for example, one cycle from a peak to a valley and back to a peak, or from a valley to a peak and back to a valley, as well as half cycles, which are half of one cycle. For example, there may be time changes in the diagnostic physical quantity or the diagnostic corrected physical quantity that do not return to the original peak level from a peak to a valley or from a valley to a peak and back to the original valley level. Hereinafter, a numerical value indicating whether the detected cycle is one cycle or a half cycle may be referred to as a "cycle value." For example, the cycle value may be "1.0" for one cycle and "0.5" for a half cycle. The waveform counting unit 703 outputs a change width ΔAj of the diagnostic physical quantity or the diagnostic corrected physical quantity in the detected cycle (hereinafter referred to as a "cycle change value")

[0082] Specifically, the waveform counting unit 703 may optionally apply a known waveform coefficient method to count cycles of change due to components corresponding to harmonics in the time change of the diagnostic physical quantity or the diagnostic correction physical quantity. Applicable waveform counting methods include, for example, the maximum-minimum method, the maximum-minimum method, the amplitude method, the level crossing method, the range pair method, the rainflow method, and the three-point cycle counting method.

[0083] The feature amount acquiring unit 704 acquires a feature amount relating to a change due to components corresponding to harmonics of the diagnostic physical quantity or the diagnostic corrected physical quantity, based on the time-series data of the cycle change value ΔAj output from the waveform counting unit 703. For example, the feature amount acquiring unit 704 acquires a feature amount that increases as the change due to components corresponding to harmonics of the diagnostic physical quantity or the diagnostic corrected physical quantity increases. This allows the control circuit 70 (diagnosis unit 706) to diagnose the degree of deterioration of the electric motor EM so that the degree of deterioration of the electric motor EM increases as the feature amount increases, as will be described later.

[0084] Specifically, the feature quantity may be a statistic obtained by statistical processing of the time-series data of the cycle change value ΔAj. The statistic related to the time-series data of the cycle change value ΔAj may be, for example, the mean, median, variance, or standard deviation of the cycle change value ΔAj. The statistic related to the time-series data of the cycle change value ΔAj may also be, for example, the number of occurrences or frequency of the cycle change value ΔAj equal to or greater than a predetermined standard. The predetermined standard may be, for example, a lower limit value of the cycle change value ΔAj at which an abnormality is assumed to occur in the electric motor EM, and may be determined in advance through experiments or simulations related to the electric motor EM. The statistic related to the time-series data of the cycle change value ΔAj may also be, for example, the value of an evaluation function that uses some or all of the time-series data of the cycle change value ΔAj as arguments.

[0085] The operating time acquisition unit 705 (an example of an operating time acquisition unit) acquires the cumulative operating time of the electric motor EM from the start of use when the information on the diagnostic physical quantity is acquired. The cumulative operating time of the electric motor EM means, for example, the cumulative operating time from the start of use of the electric motor EM in a new state after shipment from the factory. The cumulative operating time of the electric motor EM when the information on the diagnostic physical quantity is acquired may be the cumulative operating time of the electric motor EM at the start of acquisition of the diagnostic physical quantity, the cumulative operating time of the electric motor EM at the end of acquisition, or the cumulative operating time of the electric motor EM at an intermediate time therebetween.

[0086] Specifically, the control circuit 70 may measure the operation time of the electric motor EM for each time from when the operation starts until when the operation stops, and may cumulatively record the measured operation time for each time in the auxiliary storage device 71, etc. In this way, the operation time acquisition unit 705 can acquire the cumulative operation time of the electric motor EM by accumulating the operation time for each time from when the use of the electric motor EM started, which is recorded in the auxiliary storage device 71, etc.

[0087] The diagnosing unit 706 diagnoses the degree of progress of deterioration of the electric motor EM (hereinafter referred to as "deterioration level") based on the feature amount output from the feature amount acquiring unit 704. Specifically, the diagnosing unit 706 may diagnose the deterioration level of the electric motor EM so that the larger the feature amount, the larger (higher) the deterioration level becomes. The following description will be given on the assumption that the diagnosing unit 706 diagnoses the deterioration level in the range of 0% to 100%.

[0088] The diagnosis unit 706 diagnoses the deterioration level of the electric motor EM, for example, based on the feature quantity output from the feature quantity acquisition unit 704, using multiple thresholds set within a range of feature quantities corresponding to a deterioration level of 0% to 100%. Specifically, different deterioration level values may be defined for each of the multiple thresholds, such that the deterioration level increases as the threshold value increases. The multiple thresholds may be defined in advance, for example, through experiments or simulations related to the deterioration of the electric motor EM. As a result, when the feature quantity output from the feature quantity acquisition unit 704 changes from a state below or equal to a certain threshold to a state above or exceeding the threshold, the diagnosis unit 706 can diagnose that the electric motor EM is in a state of deterioration level corresponding to the threshold. Therefore, the diagnosis unit 706 can diagnose the deterioration level of the electric motor EM so that the deterioration level increases stepwise in relatively large increments as the feature quantity increases.

[0089] Furthermore, the diagnosis unit 706 may diagnose the degree of deterioration of the electric motor EM, for example, using table data, a map, or the like that indicates the correlation between the feature amount and the degree of deterioration based on the feature amount output from the feature amount acquisition unit 704. The table data, map, or the like that indicates the correlation between the feature amount and the degree of deterioration may be set in advance, for example, through experiments, simulations, or the like related to the deterioration of the electric motor EM. This allows the diagnosis unit 706 to diagnose the degree of deterioration of the electric motor EM so that the degree of deterioration increases stepwise in relatively small increments as the feature amount increases.

[0090] Furthermore, the diagnosing unit 706 may diagnose the degree of deterioration of the electric motor EM, for example, using an approximation formula or the like that expresses the correlation between the feature quantity and the degree of deterioration based on the feature quantity output from the feature quantity acquiring unit 704. The approximation formula that expresses the correlation between the feature quantity and the degree of deterioration may be set in advance, for example, through experiments, simulations, or the like related to the deterioration of the electric motor EM. This allows the diagnosing unit 706 to diagnose the degree of deterioration of the electric motor EM so that the degree of deterioration changes substantially continuously as the feature quantity increases, for example.

[0091] Instead of using the information on the diagnostic correction physical quantity described above, the above-described plurality of thresholds, approximate expressions and table data representing the correlation between the feature quantity and the deterioration degree may be corrected based on information on the rotation speed of the electric motor EM, assuming the diagnostic physical quantity.

[0092] Furthermore, the diagnosing unit 706 may diagnose the lifespan of the electric motor EM based on the diagnosis result of the deterioration level of the electric motor EM and the accumulated operating time of the electric motor EM corresponding to the diagnosis result. Specifically, the diagnosing unit 706 may diagnose (estimate) the remaining lifespan of the electric motor EM, i.e., the remaining operable time. The accumulated operating time of the electric motor EM corresponding to the diagnosis result means the accumulated operating time of the electric motor EM at the time of acquiring the diagnostic physical quantity used directly for the diagnosis or indirectly via the diagnostic correction physical quantity.

[0093] For example, the diagnosis unit 706 may estimate the remaining operable time of the electric motor EM based on the latest diagnosis result of the deterioration level of the electric motor EM and the cumulative operating time of the electric motor EM corresponding to the diagnosis result. Specifically, the diagnosis unit 706 may adjust the parameters of the reference approximation formula or table data that expresses the correlation between the passage of the cumulative operating time of the electric motor EM and the progression of the deterioration level to match the latest diagnosis result of the deterioration level of the electric motor EM and the cumulative operating time corresponding to the diagnosis result. Then, based on the adjusted approximation formula or table data, the diagnosis unit 706 may obtain the cumulative operating time of the electric motor EM when the deterioration level of the electric motor EM is 100%, and subtract the cumulative operating time corresponding to the diagnosis result to estimate the remaining operable time of the electric motor EM.

[0094] Furthermore, for example, the diagnosis unit 706 may estimate the remaining operable time of the electric motor EM using not only the latest diagnosis result of the deterioration level of the electric motor EM but also past diagnosis results of the deterioration level of the electric motor EM. That is, the diagnosis unit 706 may estimate the remaining operable time of the electric motor EM based on the history of diagnosis results of the deterioration level of the electric motor EM and the history of the cumulative operating time of the electric motor EM corresponding to those diagnosis results. Specifically, the diagnosis unit 706 may use a known extrapolation method based on the history of diagnosis results of the deterioration level of the electric motor EM and the history of the cumulative operating time corresponding to those diagnosis results to obtain the cumulative operating time of the electric motor EM when the deterioration level of the electric motor EM is 100%. Then, the diagnosis unit 706 may estimate the remaining operable time of the electric motor EM by subtracting the cumulative operating time corresponding to the latest diagnosis result from the cumulative operating time of the electric motor EM when the deterioration level of the electric motor EM is 100%.

[0095] The notification unit 707 notifies the user of the diagnostic system 1 of the diagnosis result by the diagnosis unit 706. This allows the user to understand the degree of deterioration of the electric motor EM and the remaining operable time. This allows the user to plan maintenance or replacement of the electric motor EM before a failure occurs in the electric motor EM. As a result, the control circuit 70 can perform maintenance according to the condition of the electric motor EM and reduce the risk of sudden shutdown of the equipment driven by the electric motor EM and long-term shutdown of the equipment due to the recovery work.

[0096] The notification unit 707 notifies the user of the diagnosis result of the diagnosis unit 706 by, for example, displaying the diagnosis result by the diagnosis unit 706 on the display unit 80 .

[0097] Furthermore, the notification unit 707 may transmit the diagnosis result by the diagnosis unit 706 to the management device 200 or the terminal device 300, for example, via the communication unit 90. This allows the management device 200 to notify the user of the diagnosis result via the display device 208 or the like. Similarly, the terminal device 300 can notify the user of the diagnosis result via the display device or the like. That is, the notification unit 707 can notify the user of the diagnosis result by the diagnosis unit 706 via the management device 200 or the terminal device 300.

[0098] [Example of an abnormality caused by motor deterioration] Next, a specific example of when an abnormality occurs due to deterioration of the electric motor EM will be described with reference to FIGS.

[0099] Fig. 4 is a diagram showing an example of the results of the waveform counting process and the feature amount acquisition process performed by the waveform counting unit 703 and the feature amount acquisition unit 704. Fig. 5 is a diagram showing an example of the distribution of the occurrence frequency of the cycle change value ΔAj when an abnormality occurs due to deterioration of the electric motor EM.

[0100] 4, the cycle change value ΔAj of the cycle detected by the waveform counter 703, the cycle value, and the statistics (mean, variance, and median) of the time series data of the cycle change value ΔAj are shown as time series data over time from top to bottom. The statistics of the time series data of the cycle change value ΔAj correspond to the features acquired by the feature acquisition unit 704. The statistics of the time series data of the cycle change value ΔAj are calculated based on the time series data of the cycle change value ΔAj before the target cycle.

[0101] Fig. 5 shows the distribution of the occurrence frequency of the cycle change value ΔAj corresponding to the results of the waveform counting process and feature amount acquisition process of Fig. 4, and graphs 501 and 502 show the distribution of the occurrence frequency of the cycle change value ΔAj immediately before and after the occurrence of an abnormality due to deterioration of the electric motor EM, respectively. Specifically, graph 501 shows the distribution of the occurrence frequency of the cycle change value ΔAj for the time-series data 401 of Fig. 4, and graph 502 shows the distribution of the occurrence frequency of the cycle change value ΔAj for the entire time-series data 400 of Fig. 4.

[0102] As shown in FIG. 4, within the range of time series data 401 of the entire time series data 400, the cycle change value ΔAj is relatively small, and the electric motor EM is in a normal state. In this case, the statistics (mean, variance, and median) of the time series data of the cycle change value ΔAj are relatively small. On the other hand, within the range of time series data 402 of the entire time series data 400, the cycle change value ΔAj is relatively large, and the electric motor EM is in an abnormal state due to deterioration. In this case, the statistics (mean, variance, and median) of the time series data of the cycle change value ΔAj are relatively large. Therefore, the diagnosing unit 706 can diagnose the degree of deterioration of the electric motor EM based on the magnitude of the statistics of the cycle change value ΔAj as a feature.

[0103] 5, when an abnormality occurs due to deterioration of the electric motor EM, the number of occurrences of cycle change values ΔAj in a relatively large range increases. Therefore, the diagnosing unit 706 can diagnose the degree of deterioration of the electric motor EM based on the number of occurrences or frequency of cycle change values ΔAj that are equal to or greater than a predetermined standard (in this example, "12" or "14").

[0104] [Specific example of diagnostic processing] Next, a specific example of the diagnostic processing by the control circuit 70 will be described with reference to FIGS.

[0105] Fig. 6 is a main flowchart showing an example of the diagnostic processing. Fig. 7 is a sub-flowchart showing an example of the diagnostic processing. Specifically, Fig. 7 is a sub-flowchart showing details of the processing of step S114 in Fig. 6.

[0106] The main flowchart of FIG. 6 is automatically executed at a predetermined timing, for example. The predetermined timing may be, for example, when the power conversion device 100 and the electric motor EM start operation after activation. The main flowchart of FIG. 6 is started, for example, when a predetermined input requesting diagnostic processing is received from a user. The predetermined input requesting diagnostic processing from the user may be received, for example, through a predetermined input unit provided in the power conversion device 100. The predetermined input requesting diagnostic processing from the user may be received by the communication unit 90 receiving a signal representing the predetermined user input via the input device 207 of the management device 200 or an input device of the terminal device 300.

[0107] As shown in FIG. 6, in step S102, the diagnostic information acquisition unit 701 acquires time-series data of detected values of the three phase currents of the electric motor EM for a predetermined period based on the output of the current sensor 40.

[0108] When the process of step S102 is completed, the control circuit 70 proceeds to step S104.

[0109] In step S104, the operation time acquisition unit 705 acquires the cumulative operation time of the electric motor EM at the time of acquiring the time series data of the detected values of the phase current in step S102.

[0110] When the process of step S104 is completed, the control circuit 70 proceeds to step S106.

[0111] In step S106, the diagnostic information acquisition unit 701 acquires time series data for a predetermined period of two-phase AC current values (d-axis current value and q-axis current value) in a rotating coordinate system as diagnostic physical quantities based on the three-phase phase currents of the electric motor EM acquired in step S102.

[0112] When the process of step S106 is completed, the control circuit 70 proceeds to step S108.

[0113] In step S108, the peak detector 702 detects peak values Aj by detecting peak portions from the time series data of the d-axis current value and the q-axis current value for a predetermined period.

[0114] When the process of step S108 is completed, the control circuit 70 proceeds to step S110.

[0115] In step S110, the waveform counter 703 detects the cycle of the time change of the d-axis current value or the q-axis current value, and acquires the cycle change value ΔAj.

[0116] When the process of step S110 is completed, the control circuit 70 proceeds to step S112.

[0117] In step S112, the feature amount acquiring unit 704 acquires a feature amount F relating to the change over time of the d-axis current value or the q-axis current value.

[0118] When the process of step S112 is completed, the control circuit 70 proceeds to step S114.

[0119] In step S114, the diagnosing unit 706 diagnoses the degree of deterioration of the electric motor EM based on the feature amount F acquired in step S112. For example, the degree of deterioration of the electric motor EM is diagnosed by the processing of the sub-flowchart in FIG.

[0120] 7, in step S1141, the diagnosis unit 706 determines whether the feature amount F is equal to or greater than a threshold value F1. If the feature amount F is not equal to or greater than the threshold value F1 (>0), the diagnosis unit 706 proceeds to step S1142, and if the feature amount F is equal to or greater than the threshold value F1, the diagnosis unit 706 proceeds to step S1143.

[0121] In step S1142, diagnosing unit 706 diagnoses that there is no deterioration in electric motor EM, that is, that the degree of deterioration is 0%.

[0122] When the process of step S1142 is completed, the control circuit 70 ends the process of the sub-flowchart.

[0123] On the other hand, in step S1143, the diagnosis unit 706 determines whether the feature F is equal to or greater than the threshold value F2 (>F1). If the feature F is not equal to or greater than the threshold value F2, the diagnosis unit 706 proceeds to step S1144, and if the feature F is equal to or greater than the threshold value F2, the diagnosis unit 706 proceeds to step S1145.

[0124] In step S1144, diagnosing unit 706 diagnoses that the degree of deterioration of electric motor EM is X1 [%] (>0%).

[0125] When the process of step S1144 is completed, the control circuit 70 ends the process of this sub-flowchart.

[0126] On the other hand, in step S1145, the diagnosis unit 706 determines whether the feature F is equal to or greater than a threshold F3 (>F2). If the feature F is not equal to or greater than the threshold F3, the diagnosis unit 706 proceeds to step S1146, and if the feature F is equal to or greater than the threshold F3, the diagnosis unit 706 proceeds to step S1147.

[0127] In step S1146, diagnosis unit 706 diagnoses that the degree of deterioration of electric motor EM is X2 [%] (>X1 [%]).

[0128] When the process of step S1146 is completed, the control circuit 70 ends the process of this sub-flowchart and

[0129] On the other hand, in step S1147, diagnosing unit 706 diagnoses that the deterioration level of electric motor EM is 100% (>X2 [%]).

[0130] When the process of step S1147 is completed, the control circuit 70 ends the process of this flowchart.

[0131] Returning to FIG. 6, when the control circuit 70 completes the process of step S114, the process proceeds to step S116.

[0132] In step S116, the diagnosing unit 706 diagnoses the life of the electric motor EM based on the diagnosis result of the deterioration level of the electric motor EM and the accumulated operating time acquired in step S104.

[0133] The process of step S116 may be omitted.

[0134] When the process of step S116 is completed, the control circuit 70 proceeds to step S118.

[0135] In step S118, the notification unit 707 notifies the user of the diagnosis results of steps S114 and S116 via the display unit 80, the management device 200, the terminal device 300, or the like.

[0136] When the process of step S118 is completed, the control circuit 70 ends the process of the main flowchart.

[0137] [Effect] Next, the operation of the power conversion device 100 (control circuit 70) according to this embodiment will be described.

[0138] In this embodiment, the power conversion device 100 (control circuit 70) includes a diagnostic information acquisition unit 701, a feature amount acquisition unit 704, and a diagnosis unit 706. Specifically, the diagnostic information acquisition unit 701 acquires information about an electrical physical quantity (diagnostic physical quantity) that represents the driving state of the electric motor EM. Furthermore, the feature amount acquisition unit 704 acquires a feature amount related to a time change in the electrical physical quantity. Then, the diagnosis unit 706 diagnoses the degree of progress of deterioration (deterioration level) of the electric motor EM based on the feature amount.

[0139] As a result, the control circuit 70 can notify the user of the degree of deterioration (progression of deterioration) that could lead to a failure of the electric motor EM before the electric motor EM fails and a sudden shutdown of equipment driven by the electric motor EM occurs. Therefore, the control circuit 70 can appropriately prompt the user to plan and execute a maintenance program in accordance with the condition of the electric motor EM, thereby reducing the frequency of maintenance of equipment including the electric motor EM. Furthermore, the control circuit 70 can reduce the risk of a sudden shutdown of equipment including the electric motor EM and long-term shutdown of the equipment due to recovery work.

[0140] Furthermore, for example, it is possible to diagnose deterioration of the electric motor EM by focusing on the frequency components of the electrical physical quantities of the electric motor EM, but this requires spectral analysis using a fast Fourier transform (FFT), etc. As a result, the spectral analysis, etc., increases the processing load for diagnosing abnormalities, which may strain the resources of the control circuit 70, or may require the introduction of expensive measuring equipment to suppress strain on the resources of the control circuit 70.

[0141] In contrast to this, in this embodiment, by utilizing feature quantities relating to time-dependent changes in electrical physical quantities of the electric motor EM, it is possible to reduce the processing load for diagnosing the electric motor EM.

[0142] In addition, in this embodiment, the diagnosing unit 706 may diagnose the degree of progress of deterioration of the electric motor EM so that the greater the feature amount, the greater the degree of progress of the deterioration.

[0143] This allows the control circuit 70 to specifically diagnose the degree of progress of deterioration of the electric motor EM in accordance with an increase in the feature amount.

[0144] In this embodiment, multiple thresholds may be set, and the diagnosing unit 706 may diagnose the degree of deterioration such that the degree of deterioration increases each time the feature amount exceeds a threshold, starting from a smaller one of the multiple thresholds.

[0145] This allows the control circuit 70 to specifically diagnose the degree of progress of deterioration of the electric motor EM in accordance with an increase in the feature amount.

[0146] Furthermore, in this embodiment, the control circuit 70 may include a peak detection unit 702 and a waveform counting unit 703. Specifically, the peak detection unit 702 may detect peaks in the time change of an electrical physical quantity representing the driving state of the electric motor EM. Furthermore, the waveform counting unit 703 may detect a cycle of the time change of the electrical physical quantity representing the driving state of the electric motor EM based on a history of the peak values (peak values Aj) detected by the peak detection unit 702. Then, the feature acquisition unit 704 may acquire a feature based on a history of the change width (cycle change value ΔAj) of the electrical physical quantity representing the driving state of the electric motor EM in the cycle detected by the waveform counting unit 703.

[0147] This allows the control circuit 70 to specifically acquire the feature amount.

[0148] In this embodiment, the control circuit 70 may also include an operation time acquisition unit 705. Specifically, the operation time acquisition unit 705 may acquire the operation time of the electric motor EM since the start of use. The diagnosis unit 706 may then diagnose the lifespan of the electric motor EM based on the diagnosis result of the degree of deterioration and the operation time of the electric motor EM corresponding to the diagnosis result.

[0149] This allows the control circuit 70 to notify the user of the remaining lifespan (remaining operable time) of the electric motor EM in addition to the degree of deterioration of the electric motor EM. Therefore, the control circuit 70 can more appropriately prompt the user to plan and execute a maintenance plan in accordance with the condition of the electric motor EM.

[0150] In addition, in this embodiment, the diagnosis unit 706 may diagnose the lifespan of the electric motor EM based on the history of the diagnosis results of the deterioration degree and the history of the operation time of the electric motor EM corresponding to the history of the diagnosis results.

[0151] This allows the control circuit 70 to estimate the remaining life (remaining operable time) of the electric motor EM with higher accuracy.

[0152] In this embodiment, the electrical physical quantity representing the driving state of the electric motor EM may be the current, voltage, or power of the electric motor EM.

[0153] This allows the control circuit 70 to grasp the time-dependent changes in the current, voltage, or power of the electric motor EM, and specifically to diagnose the deterioration of the electric motor EM.

[0154] In this embodiment, the diagnostic information acquisition unit 701 may acquire information related to the rotation speed of the electric motor EM. Then, the diagnosis unit 706 may diagnose the degree of deterioration of the electric motor EM based on the information related to the rotation speed.

[0155] This allows the control circuit 70 to diagnose the degree of deterioration of the electric motor EM by taking into consideration changes in the electrical physical quantity that indicates the driving state of the electric motor EM due to the rotation state (rotation speed) of the electric motor EM. As a result, the control circuit 70 can diagnose the degree of deterioration of the electric motor EM with higher accuracy.

[0156] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0157] 1 Diagnostic System 10 Rectifier circuit 20 Smoothing circuit 21 Smoothing capacitor 30 Inverter circuit 40 Current Sensor 50 Voltage Sensor 60 Gate drive circuit 70 Control circuit 71 Auxiliary storage device 72 Memory Device 73 CPU 74 Interface Device 80 Display section 90 Communications Department 100 Power conversion device 200 Management device 201 External Interface 201A Recording Media 202 Auxiliary storage 203 Memory Device 204 CPU 205 High-speed calculation equipment 206 Communication Interface 207 Input Device 208 Display device 300 Terminal Equipment 701 Diagnostic information acquisition unit 702 Peak detector 703 Waveform Counter 704 Feature Acquisition Unit 705 Driving time acquisition unit 706 Diagnostic Department 707 Notification Department B1 Bus B2 Bus EM electric motor NL Negative Line PL positive line PS commercial power supply SD Semiconductor Diode SW Semiconductor switch

Claims

1. a first information acquisition unit that acquires information about an electrical physical quantity that represents a driving state of the AC motor; a peak detection unit that detects peaks and valleys as peaks in the time change of the electrical physical quantity; a cycle detection unit that detects a cycle of a time change in the electrical physical quantity by a waveform counting method based on a history of peak and valley values detected by the peak detection unit; a feature acquisition unit that acquires a feature relating to a time change in the electrical physical quantity based on an entire history of a change range of the electrical physical quantity in each of a plurality of cycles detected by the cycle detection unit, for time-series data of the electrical physical quantity for a predetermined period of time; a diagnosis unit that diagnoses a degree of deterioration of the AC motor based on the feature amount, Diagnostic equipment.

2. the diagnosing unit diagnoses the degree of progress of the deterioration such that the degree of progress of the deterioration increases as the feature amount increases. The diagnostic device of claim 1 .

3. Multiple thresholds are provided, the diagnosing unit diagnoses the degree of progress of the deterioration such that the degree of progress of the deterioration increases each time the feature amount exceeds a threshold value from a smaller one of the plurality of threshold values. The diagnostic device of claim 2 .

4. an operating time acquisition unit that acquires an operating time from the start of use of the AC motor; the diagnosing unit diagnoses a lifespan of the AC motor based on a diagnosis result of the degree of progress of the deterioration and the operating time of the AC motor corresponding to the diagnosis result. A diagnostic device according to any one of claims 1 to 3.

5. the diagnosing unit diagnoses a lifespan of the AC motor based on a history of diagnostic results of the degree of progress of the deterioration and a history of the operating time of the AC motor corresponding to the history of the diagnostic results. The diagnostic device according to claim 4.

6. The electrical physical quantity is a current, a voltage, or a power of the AC motor. A diagnostic device according to any one of claims 1 to 5.

7. a second information acquisition unit that acquires information about a rotation speed of the AC motor; the diagnosing unit diagnoses a degree of progress of the deterioration of the AC motor based on information related to the rotation speed. A diagnostic device according to any one of claims 1 to 6.

8. A power conversion device that supplies drive power to the AC motor based on power input from an external source, A diagnostic device comprising the diagnostic device according to any one of claims 1 to 7. Power conversion device.

9. a first information acquisition step in which the diagnostic device acquires information about an electrical physical quantity that represents a driving state of the AC motor; a peak detection step in which the diagnostic device detects peaks and valleys as peaks in the time change of the electrical physical quantity; a cycle detection step in which the diagnostic device detects a cycle of time change of the electrical physical quantity by a waveform counting method based on a history of peak and valley values detected in the peak detection step; a feature acquisition step in which the diagnostic device acquires a feature relating to a time change in the electrical physical quantity based on an entire history of a range of change in the electrical physical quantity in each of a plurality of cycles detected in the cycle detection step, for time-series data of the electrical physical quantity for a predetermined period of time; a diagnosing step in which the diagnosing device diagnoses a degree of deterioration of the AC motor based on the feature amount, Diagnostic methods.

10. For diagnostic equipment, a first information acquisition step of acquiring information about an electrical physical quantity that represents a driving state of the AC motor; a peak detection step of detecting peaks and valleys as peaks in the time change of the electrical physical quantity; a cycle detection step of detecting a cycle of time change of the electrical physical quantity by a waveform counting method based on a history of the peak and valley values detected in the peak detection step; a feature acquisition step of acquiring a feature relating to a time change in the electrical physical quantity based on an entire history of a change range of the electrical physical quantity in each of a plurality of cycles detected in the cycle detection step, for time-series data of the electrical physical quantity for a predetermined period of time; a diagnosis step of diagnosing a degree of deterioration of the AC motor based on the feature amount; program.

Images