Diagnostic device, power conversion device, and diagnostic method

Abstract

To provide a technique capable of appropriately diagnosing abnormality of an electric motor.SOLUTION: The diagnostic device 75 according to an embodiment of the present disclosure includes the computation unit 750 that computes at least one of the instantaneous active power P and the instantaneous reactive power Q of the electric motors EM, the specific frequency component extraction unit 751 that extracts the component of the specific frequency from the measurement data of at least one of the instantaneous active power P and the instantaneous reactive power Q of the electric motors EM output from the computation unit 750, and the diagnostic unit 753 that diagnoses abnormality of the electric motors EM on the basis of the component of the specific frequency of at least one of the instantaneous active power P and the instantaneous reactive power Q of the electric motors EM.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] For example, a technique is known for diagnosing an abnormality in an electric motor based on the voltage or current of the electric motor (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-140897 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the degree of abnormality indicative of an abnormality in the motor, which appears in the feature quantities related to the current or voltage of the motor, may change depending on various conditions during operation of the motor, which may make it impossible to properly diagnose the abnormality in the motor.

[0005] In view of the above, an object of the present invention is to provide a technique that can appropriately diagnose abnormalities in an electric motor. [Means for solving the problem]

[0006] In order to achieve the above object, in one embodiment of the present disclosure, Diagnosing an abnormality in the electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor; A diagnostic device is provided.

[0007] In another embodiment of the present disclosure, a main circuit section that converts externally supplied power into a predetermined power and outputs the converted power to drive the electric motor; a diagnostic unit that diagnoses an abnormality in the electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor, A power converter is provided.

[0008] In still another embodiment of the present disclosure, a diagnostic device for diagnosing an abnormality in the electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor; A diagnostic method is provided. [Effects of the Invention]

[0009] According to the above-described embodiment, it is possible to appropriately diagnose abnormalities in the electric motor. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 illustrates a configuration of an example of a diagnostic system. [Figure 2] FIG. 2 is a functional block diagram showing an example of a functional configuration of a control circuit. [Figure 3] FIG. 2 is a functional block diagram illustrating an example of a functional configuration of the diagnostic device. [Figure 4] FIG. 4 is a diagram showing a first example of the results of a simulation of the operating state of the electric motor when an abnormality occurs. [Figure 5] FIG. 4 is a diagram showing a first example of the results of a simulation of the operating state of the electric motor when an abnormality occurs. [Figure 6] FIG. 10 is a diagram showing a second example of the results of a simulation of the operating state of the electric motor when an abnormality occurs. [Figure 7] FIG. 10 is a diagram showing a second example of the results of a simulation of the operating state of the electric motor when an abnormality occurs. [Figure 8] 4 is a flowchart illustrating an example of a process for diagnosing an abnormality in an electric motor. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment will be described with reference to the drawings.

[0012] [Diagnostic system configuration] The configuration of a diagnostic system 1 according to this embodiment will be described with reference to FIG.

[0013] FIG. 1 is a diagram showing an example of the configuration of a diagnostic system 1 according to this embodiment.

[0014] As shown in FIG. 1, the diagnostic system 1 includes an electric motor EM, a power conversion device 100, a rotation state sensor 150, a management device 200, and a terminal device 300.

[0015] The diagnostic system 1 diagnoses abnormalities in the electric motor EM in the power conversion device 100 (specifically, in a diagnostic device 75 described later).

[0016] Abnormalities in the electric motor EM that are the target of diagnosis by the diagnostic system 1 include abnormalities in the electric motor EM caused by temporary causes and abnormalities in the electric motor EM caused by cumulative causes (i.e., deterioration abnormalities). Abnormalities that are the target of diagnosis by the diagnostic system 1 also include mechanical abnormalities and electrical abnormalities. For example, mechanical abnormalities in the electric motor EM that are the target of diagnosis by the diagnostic system 1 include bearing abnormalities, etc. Furthermore, electrical abnormalities in the electric motor EM that are the target of diagnosis by the diagnostic system 1 include insulation deterioration (layer shorts) of the electric motor EM, etc.

[0017] Diagnosis of an abnormality in the electric motor EM includes, for example, diagnosis of whether or not there is an abnormality in the electric motor EM. Diagnosis of an abnormality in the electric motor EM may also include diagnosis of whether or not there are signs of an abnormality in the electric motor EM. Diagnosis of an abnormality in the electric motor EM may also include diagnosis of the degree of the abnormality in the electric motor EM.

[0018] The electric motor EM drives, for example, production equipment or machinery installed in a factory. The electric motor EM is, for example, an AC motor such as an induction motor or a synchronous motor.

[0019] 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.

[0020] The power conversion device 100 includes a main circuit 100MC, a current sensor 40, a voltage sensor 50, a gate drive circuit 60, a control circuit 70, a diagnostic device 75, a display unit 80, and a communication unit 90.

[0021] The main circuit 100MC includes a rectifier circuit 10, a smoothing circuit 20, and an inverter circuit 30.

[0022] The rectifier circuit 10 is configured to rectify three-phase AC power input from a commercial power supply PS and output DC power. The rectifier circuit 10 has positive and negative output terminals connected to one end of a positive line PL and a negative line NL, respectively, and can output DC to the smoothing circuit 20 via the positive line PL and the negative line NL.

[0023] 1, the rectifier circuit 10 is a bridge-type full-wave rectifier circuit including six rectifier diodes SD, with three sets of two-to-one series-connected rectifier diodes SD constituting upper and lower arms connected in parallel. In this case, the R-phase, S-phase, and T-phase input lines are connected to the midpoints of the three sets of upper and lower arms, respectively.

[0024] The smoothing circuit 20 suppresses and smoothes pulsations in the direct current output from the rectifier circuit 10 and the direct current regenerated from the inverter circuit 30 .

[0025] For example, as shown in FIG. 1, the smoothing circuit 20 includes a smoothing capacitor 21.

[0026] The smoothing capacitor 21 may be provided in parallel with the rectifier circuit 10 and the inverter circuit 30 so as to electrically connect the positive line PL and the negative line NL.

[0027] The smoothing capacitor 21 smoothes the DC power output from the rectifier circuit 10 and the DC output (regenerated) from the inverter circuit 30 while repeatedly charging and discharging as appropriate.

[0028] 1, for example, there is 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.

[0029] The smoothing circuit 20 may also include a reactor.

[0030] The reactor is provided, for example, on the positive line PL between the rectifier circuit 10 and the smoothing capacitor 21.

[0031] The reactor smoothes the direct current output from the rectifier circuit 10 and the direct current output (regenerated) from the inverter circuit 30 while generating a voltage to appropriately prevent a change in the current.

[0032] The inverter circuit 30 has positive and negative inputs 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 (i.e., AC of 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 converted power to the electric motor EM.

[0033] The semiconductor switch SW is, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), or a HEMT (High Electron Mobility Transistor). The semiconductor switch SW is, for example, made primarily of silicon (Si). The semiconductor switch SW may also be made primarily of a wide bandgap semiconductor material. Examples of wide bandgap semiconductor materials include silicon carbide (SiC), gallium nitride (gallium nitride: GaN), gallium oxide (gallium oxide: Ga2O3), and carbon (diamond: C).

[0034] For example, as shown in Fig. 1, the inverter circuit 30 includes six semiconductor switches SW. Specifically, the inverter circuit 30 may include a bridge circuit in which three sets of series-connected assemblies (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. In this case, the inverter circuit 30 outputs three-phase AC power through three output lines drawn from the connection points of the three sets of upper and lower arms. In addition, a free-wheeling diode may be connected in parallel to each of the six semiconductor switches SW.

[0035] The current sensor 40 detects the currents in the three-phase output lines of the power conversion device 100, i.e., the currents in the three phases of the electric motor EM. The current sensor 40 detects the currents using, for example, a Hall element, a shunt resistor, a magnetoresistive element, a fluxgate, etc., and obtains the detected current values ​​(digital values) using an AD (Analog-Digital) converter. The current sensor 40 outputs signals corresponding to the detected current values ​​in the three phases of the electric motor EM, and the output signals of the current sensor 40 are taken into the control circuit 70.

[0036] The current sensor 40 may detect currents of any two phases among the three-phase output lines of the power conversion device 100. In this case, the control circuit 70 may acquire (calculate) the current value of the remaining phase from the detected values ​​of the currents of the two phases. The control circuit 70 may also acquire (calculate, specifically) 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 acquire (calculate, specifically) the current values ​​of the DC links based on the output of the voltage sensor 50.

[0037] 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.

[0038] 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.

[0039] The control circuit 70 controls the power conversion device 100 .

[0040] The functions of the control circuit 70 may be realized by any hardware or a combination of any hardware and software. The control circuit 70 is configured by a computer or the like including a CPU (Central Processing Unit), a memory device, an auxiliary storage device, and an interface device. The memory device is, for example, a static random access memory (SRAM). The auxiliary storage device is, for example, an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The interface device includes, for example, an external interface for connecting to an external recording medium and a communication interface for communicating with other devices. The control circuit 70 can realize various functions by loading programs installed in the auxiliary storage device into the memory device and executing them on the CPU. The control circuit 70 can also retrieve and install programs from a recording medium via the external interface, or retrieve and install programs from other devices via the communication interface.

[0041] The control circuit 70 controls the inverter circuit 30 so that the electric motor EM operates under predetermined operating conditions, for example, and drives the electric motor EM under the predetermined operating conditions.

[0042] The functions of the control circuit 70 may be distributed among a plurality of control circuits mounted on the power conversion device 100.

[0043] The diagnostic device 75 diagnoses abnormalities in the electric motor EM.

[0044] The functions of the diagnostic device 75 may be realized by any hardware or a combination of any hardware and software. The diagnostic device 75 is configured by a computer or the like including a CPU, a memory device, an auxiliary storage device, and an interface device. The memory device is, for example, an SRAM. The auxiliary storage device is, for example, an EEPROM or flash memory. The interface device includes, for example, an external interface for connecting to an external recording medium and a communication interface for communicating with other devices. The diagnostic device 75 can realize various functions by loading programs installed in the auxiliary storage device into the memory device and executing them on the CPU. The diagnostic device 75 can also retrieve and install programs from a recording medium via the external interface, or retrieve and install programs from other devices via the communication interface.

[0045] 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 and the diagnostic device 75. The display unit 80 includes, for example, a warning light, an electronic bulletin board, a liquid crystal display, an organic EL (Electroluminescence) display, etc.

[0046] The communication unit 90 communicates with an external device of the power conversion device 100 through a predetermined communication line.

[0047] 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.

[0048] The function of the communication unit 90 may be built into the control circuit 70 or the diagnostic device 75 as one function of the interface device.

[0049] The rotation state sensor 150 is attached to, for example, the electric motor EM and detects physical quantities that represent the rotation state of the electric motor EM, such as the rotational position and rotational speed. For example, the rotation state sensor 150 is an optical or magnetic encoder. The rotation state sensor 150 outputs a signal corresponding to the detected value of the rotational speed of the electric motor EM, and the output signal of the rotation state sensor 150 is input to the control circuit 70 of the power conversion device 100. As a result, the control circuit 70 can determine the magnetic pole position and rotational speed of the rotor of the electric motor EM based on the detection signal of the rotation state sensor 150.

[0050] The management device 200 is provided outside the power conversion device 100. As a higher-level device of the power conversion device 100, the management device 200 is communicably connected to the power conversion device 100 and performs management related to the power conversion device 100 and the electric motor EM.

[0051] 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 performs processing related to a function for monitoring the states of the power conversion device 100 and the electric motor EM. The management device 200 also performs processing related to an interface function related to communication between the power conversion device 100 and users, such as workers or managers of a factory where the power conversion device 100 and the electric motor EM are installed. Specifically, the management device 200 may perform processing for providing information related to the electric motor EM and the power conversion device 100, and for receiving input from a user and transmitting the information to the power conversion device 100.

[0052] 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 terminal device for managing machinery and production equipment in the factory. 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 a portable terminal device (i.e., a mobile terminal) that can be carried by a factory manager, worker, 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.

[0053] The functions of the management device 200 are realized by any hardware or any combination of hardware and software. For example, the management device 200 is primarily configured with a computer including a CPU, a memory device, an auxiliary storage device, a high-speed arithmetic device, and an interface device. The management device 200 may also include user interface devices such as an input device and a display device. The memory device includes, for example, an SRAM or a DRAM (Dynamic Random Access Memory). The auxiliary storage device includes, for example, a hard disk drive (HDD), a solid state drive (SSD), an EEPROM, or a flash memory. The high-speed arithmetic device includes, for example, a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). The interface device includes, for example, an external interface for connecting to an external recording medium and a communication interface for communicating with other devices. The management device 200 can realize various functions by loading programs installed in the auxiliary storage device into the memory device and executing them on the CPU. The management device 200 can also retrieve and install programs from a recording medium via an external interface, or retrieve and install programs from other devices via a communication interface. Examples of input devices include a keyboard, a mouse, a touch panel, etc. Examples of display devices include a liquid crystal display, an organic EL display, etc.

[0054] The terminal device 300 is a user terminal that is provided outside the power conversion apparatus 100 and is used by a user of the diagnostic system 1. The user of the diagnostic system 1 is, for example, a manager or worker of a factory in which production equipment or machinery driven by the electric motor EM is installed. The terminal device 300, for example, provides the user with various information related to the states of the power conversion apparatus 100 and the electric motor EM, accepts various inputs from the user, and transmits the inputs to the power conversion apparatus 100. The terminal device 300 may acquire information related to the electric motor EM and the power conversion apparatus 100 via the management device 200, or may acquire information related to the electric motor EM and the power conversion apparatus 100 directly from the power conversion apparatus 100. Similarly, the terminal device 300 may transmit various inputs from the user to the power conversion apparatus 100 via the management device 200, or may transmit the inputs from the user directly to the power conversion apparatus 100.

[0055] 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.

[0056] The functions of the terminal device 300 are realized by any hardware or a combination of any hardware and software. For example, the terminal device 300 is mainly composed of a computer including a CPU, a memory device, an auxiliary storage device, and an interface device, as well as user interface devices such as an input device and a display device. The memory device includes, for example, SRAM and DRAM. The auxiliary storage device includes, for example, a HDD, an SSD, an EEPROM, and a flash memory. The interface device includes, for example, an external interface for connecting to an external recording medium and a communication interface for communicating with other devices. The terminal device 300 can realize various functions by loading programs installed in the auxiliary storage device into the memory device and executing them on the CPU. The terminal device 300 can also retrieve and install programs from a recording medium via an external interface, or retrieve and install programs from other devices via a communication interface. The input device includes, for example, a button switch, a keyboard, a mouse, a touch panel, etc. The display device includes, for example, a liquid crystal display, an organic electroluminescence (EL) display, etc.

[0057] At least one of the management device 200 and the terminal device 300 may be omitted.

[0058] [Control circuit functional configuration] Next, the functional configuration of the control circuit 70 according to this embodiment will be described with reference to FIG.

[0059] FIG. 2 is a functional block diagram showing an example of the functional configuration of the control circuit 70. As shown in FIG.

[0060] As shown in FIG. 2, the control circuit 70 includes, as functional units, a speed adjustment unit 701, a current detection unit 702, a vector conversion unit 703, a current adjustment unit 704, a vector inverse conversion unit 705, a voltage compensation unit 706, and a gate signal output unit 707.

[0061] Based on a command value for the rotational speed of the electric motor EM (hereinafter referred to as "speed command value") and a detected value for the rotational speed of the electric motor EM (hereinafter referred to as "detected speed value"), the speed adjustment unit 701 outputs a control command value for the current of the electric motor EM (hereinafter referred to as "current command value") to bring the deviation closer to zero. The speed command value is specified according to predetermined operating conditions of the electric motor EM. The detected speed value is acquired based on a signal captured from the rotation state sensor 150. In this example, the speed adjustment unit 701 outputs current commands for the d-axis and q-axis of a dq rotating coordinate system fixed to the electric motor EM. The speed adjustment unit 701 is, for example, a proportional integral (PI) controller.

[0062] For example, when sensorless control is employed, an estimated value of the rotation speed of the electric motor EM (estimated speed value) is used instead of the detected speed value of the electric motor EM. In this case, the rotation state sensor 150 is omitted. When speed control is not employed, the speed adjustment unit 701 is omitted. For example, when torque control or current control is employed, the speed adjustment unit 701 is omitted. In this case, the current command value is generated based on the torque command value in torque control, or based on the current command values ​​of the U-phase, V-phase, and W-phase in current control.

[0063] The current detection unit 702 acquires and outputs current detection values ​​of the U-phase, V-phase, and W-phase of the electric motor EM based on the signal received from the current sensor 40 .

[0064] The vector conversion unit 703 converts the output of the current detection unit 702 (current detection values ​​of the U phase, V phase, and W phase) into current detection values ​​of the d axis and q axis of a dq rotating coordinate system based on information such as the electrical angle θ of the electric motor EM and the magnetic pole position, and outputs the converted values.

[0065] The electrical angle θ of the electric motor EM is calculated based on a detected value or an estimated value of the rotation speed of the electric motor EM.

[0066] Based on the deviation between the d-axis and q-axis current command values ​​and the d-axis and q-axis current detection values, the current adjustment unit 704 outputs command values ​​(voltage command values) related to the d-axis and q-axis voltages of the electric motor EM to bring the deviation closer to zero. The current adjustment unit 704 is, for example, a PI controller.

[0067] The vector inverse converter 705 converts the d-axis and q-axis voltage command values ​​into U-phase, V-phase, and W-phase voltage command values ​​based on the electrical angle θ of the electric motor EM, information on the magnetic pole position, and the like, and outputs them.

[0068] The voltage compensator 706 corrects the voltage command values ​​of the outputs (U-phase, V-phase, and W-phase) of the vector inverse converter 705 so as to compensate for deviations from the voltage command values ​​of the voltages applied to the electric motor EM from the power converter 100 (inverter circuit 30). For example, the voltage compensator 706 corrects the voltage command values ​​for voltage compensation related to the dead time of the inverter circuit 30, and outputs the corrected voltage command values ​​of the U-phase, V-phase, and W-phase.

[0069] The voltage compensation unit 706 may be omitted.

[0070] The gate signal output unit 707 generates a signal (gate signal) for applying a voltage to the gate of the semiconductor switch SW in the inverter circuit 30 based on the output of the voltage compensation unit 706 (voltage command values ​​for the U phase, V phase, and W phase), and outputs the generated signal to the gate drive circuit 60. The gate signal is, for example, a PWM (Pulse Width Modulation) signal. For example, the gate signal output unit 707 includes comparators corresponding to the U phase, V phase, and W phase, respectively, and outputs gate signals for the U phase, V phase, and W phase by the comparators comparing the voltage command values ​​for the U phase, V phase, and W phase with a carrier wave. This enables the control circuit 70 to output the gate signal to the gate drive circuit 60 and control the semiconductor switch SW of the inverter circuit 30.

[0071] [Functional configuration of diagnostic equipment] Next, the functional configuration of the diagnostic device 75 according to this embodiment will be described with reference to FIG.

[0072] FIG. 3 is a functional block diagram showing an example of the functional configuration of the diagnostic device 75.

[0073] As shown in FIG. 3, the diagnostic device 75 includes, as functional units, a calculation unit 750, a specific frequency component extraction unit 751, a feature amount acquisition unit 752, a diagnostic unit 753, and a notification unit 754.

[0074] The calculation unit 750 calculates the d-axis and q-axis current values ​​I d ,I q , and the d-axis and q-axis voltage values ​​V d ,V q Based on this, the instantaneous active power P and instantaneous reactive power Q of the electric motor EM are calculated. The d-axis and q-axis current values ​​I d ,I q are, for example, the d-axis and q-axis current detection values ​​of the electric motor EM output from the vector conversion unit 703 of the control circuit 70. The d-axis and q-axis voltage values ​​V d ,V q are, for example, d-axis and q-axis voltage command values ​​of the electric motor EM output from the current adjustment unit 704 of the control circuit 70. In addition, when the three-phase voltages of the inverter circuit 30 can be detected, the d-axis and q-axis voltage values ​​V d ,V q may be the d-axis and q-axis voltage detection values ​​calculated from the detected values ​​of the three phase voltages.

[0075] For example, the calculation unit 750 calculates the instantaneous active power P and the instantaneous reactive power Q using the following equation (1).

[0076]

number

[0077] In addition, equation (1) is the d-axis current value I d , and the q-axis current value I qis calculated by performing a relative transformation from three phases, U, V, and W, to two phases, α-axis and β-axis, of the αβ stationary coordinate system. When an absolute transformation is used instead of a relative transformation, the coefficient of equation (1) is replaced from "3 / 2" to "1." In addition, the instantaneous active power P and the instantaneous reactive power Q may be calculated based on the current values ​​of the α-axis and β-axis and the voltage values ​​of the α-axis and β-axis.

[0078] The specific frequency component extraction unit 751 extracts specific frequency components from each of the instantaneous active power P and the instantaneous reactive power Q output from the calculation unit 750. Specifically, the specific frequency component extraction unit 751 extracts specific frequency components from time series data for a certain period of each of the instantaneous active power P and the instantaneous reactive power Q. For example, the specific frequency component extraction unit 751 is a band-pass filter that extracts specific frequency components from each of the instantaneous active power P and the instantaneous reactive power Q.

[0079] Specific frequency components are frequency components in the current and voltage of the electric motor EM that exhibit the characteristics of the type of abnormality being diagnosed in the electric motor EM. The instantaneous active power P and instantaneous reactive power Q of the electric motor EM are calculated based on the multiplication of the current and voltage, as shown in the above formula (1). Therefore, the characteristics that appear in the specific frequency components of the current and voltage of the electric motor EM and that correspond to the type of abnormality being diagnosed also appear in the instantaneous active power P and instantaneous reactive power Q of the electric motor EM.

[0080] The specific frequency component is, for example, a frequency related to the electrical angle θ of the electric motor EM. The frequency related to the electrical angle θ of the electric motor EM is a frequency corresponding to an integer multiple of the electrical angle θ, specifically, a frequency that is an integer multiple of the rotational frequency ω. In this case, the specific frequency changes according to changes in the rotational frequency ω. Therefore, the specific frequency component extraction unit 751 may arbitrarily apply a known tracking filtering technique (see, for example, the specific frequency component extraction unit disclosed in Japanese Patent Application Laid-Open No. 2024-83207) that can extract the specific frequency component by tracking changes in the specific frequency. This allows the specific frequency component extraction unit 751 to extract the specific frequency component related to the electrical angle θ of the electric motor EM by tracking changes in the rotational frequency ω.

[0081] The feature amount acquiring unit 752 acquires feature amounts relating to an abnormality in the electric motor EM based on specific frequency components of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM.

[0082] The feature quantity relating to the abnormality of the electric motor EM is, for example, the amplitude value A of each of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM. The amplitude value A of each of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM is obtained, for example, by applying a waveform counting method to time series data of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM for a certain period of time, and extracting an amplitude value for each of multiple waveforms included in the time series data (see, for example, the waveform counting unit in JP 2023-177596 A).

[0083] Furthermore, the feature quantity relating to an abnormality in the electric motor EM may be the vector length in the dq rotating coordinate system of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM (see, for example, the feature quantity acquisition unit disclosed in JP 2024-83207 A).

[0084] The diagnosing unit 753 diagnoses an abnormality in the electric motor EM based on the feature amount acquired by the feature amount acquiring unit 752. The diagnosing unit 753 diagnoses an abnormality in the electric motor EM based on, for example, whether or not the feature amount related to the abnormality in the electric motor EM is equal to or greater than a threshold value or whether or not the feature amount exceeds a threshold value.

[0085] Specifically, for example, the diagnosing unit 753 diagnoses that the electric motor EM has an abnormality or that there is a sign of an abnormality when the amplitudes of both the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM are equal to or greater than a predetermined threshold. Alternatively, the diagnosing unit 753 may diagnose that the electric motor EM has an abnormality or that there is a sign of an abnormality when the amplitude of at least one of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM is equal to or greater than a predetermined threshold. Alternatively, the diagnosing unit 753 may diagnose that the electric motor EM has an abnormality or that there is a sign of an abnormality when the average value of the amplitudes of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM is equal to or greater than a predetermined threshold.

[0086] The amplitude of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM may be, for example, the amplitude of one waveform obtained by the above-mentioned waveform counting method, the average value of the amplitudes of all waveforms, or the maximum value of the amplitude values ​​of all waveforms.

[0087] In addition, instead of the amplitude of the instantaneous active power P and the instantaneous reactive power Q, the vector length in the dq rotating coordinate system may be used as a feature related to an abnormality in the electric motor EM, and the presence or absence of an abnormality in the electric motor EM or the presence or absence of signs of an abnormality may be diagnosed in a similar manner.

[0088] The diagnosing unit 753 may also use a frequency distribution of the amplitude magnitude of each of a plurality of waveforms included in time-series data of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM over a certain period, obtained by a waveform counting method (see, for example, the amplitude analysis unit in JP 2023-177596 A). For example, the diagnosing unit 753 may diagnose that there is an abnormality or a sign of an abnormality in the electric motor EM when the frequency distribution of the amplitudes of both the instantaneous active power P and the instantaneous reactive power Q contains an amplitude equal to or greater than a predetermined threshold, or an amplitude greater than the predetermined threshold is included a predetermined frequency or more. The diagnosing unit 753 may also diagnose that there is an abnormality or a sign of an abnormality in the electric motor EM when the frequency distribution of the amplitude of at least one of the instantaneous active power P and the instantaneous reactive power Q contains an amplitude equal to or greater than a predetermined threshold, or an amplitude greater than the predetermined threshold is included a predetermined frequency or more.

[0089] For example, the degree of an abnormality indicating an abnormality in the electric motor EM, which appears in a feature quantity related to the current or voltage of the electric motor EM, may vary depending on various conditions during operation of the electric motor EM. These various conditions include the conditions of the control method for the electric motor EM adopted by the control circuit 70, the conditions of the control gain used when the control circuit 70 controls the electric motor EM, and the operating conditions of the electric motor EM. Therefore, for example, if the diagnostic device 75 uses only the feature quantity related to either the current or the voltage of the electric motor EM, it may not be able to properly diagnose the existence of an abnormality in the electric motor EM or the presence of a symptom of an abnormality when the degree of an abnormality indicating an abnormality in the electric motor EM, which appears in the feature quantity, is relatively small. On the other hand, for example, increasing the diagnostic sensitivity to detect relatively small abnormalities appearing in the feature quantity may result in a false diagnosis of an abnormality in the electric motor EM or the presence of a symptom of an abnormality, even when no abnormality or symptom of an abnormality in the electric motor EM exists.

[0090] In contrast, in this example, the diagnostic device 75 can diagnose abnormalities in the electric motor EM using the instantaneous active power P and instantaneous reactive power Q obtained by multiplying the current and voltage of the electric motor EM. Therefore, the diagnostic device 75 can appropriately diagnose abnormalities in the electric motor EM. This is because an abnormality indicating an abnormality in the electric motor EM often appears more clearly in either the current or the voltage of the electric motor EM than in the other, and a relatively large abnormality can occur in the instantaneous active power and instantaneous reactive power obtained by multiplying the current and voltage, regardless of various conditions.

[0091] The notification unit 754 notifies the user of the diagnosis result by the diagnosis unit 753 .

[0092] For example, the notification unit 754 displays information about the diagnosis result on the display unit 80. Furthermore, the notification unit 754 may transmit a signal including information about the diagnosis result to the management device 200 or the terminal device 300 via the communication unit 90. This allows the notification unit 754 to notify the user of the diagnosis result via the management device 200 or the terminal device 300.

[0093] The information relating to the diagnosis result may be transmitted from the power electronics device 100 (communication unit 90) to the terminal device 300 via the management device 200.

[0094] [Diagnosis method for rare short circuits in electric motors] Next, a specific example of a diagnostic method for a specific type of abnormality in the electric motor EM will be described. In this example, a specific example of a diagnostic method for a layer short in the electric motor EM will be described.

[0095] In an electric motor EM, gaps or damaged areas in insulating materials (such as the bobbin, insulating paper, or conductive insulating coating of the winding) caused by mechanical stress or thermal degradation can cause discharges and lead to a layer short circuit (insulation degradation) in the armature winding. When a layer short circuit occurs in the armature winding, a reverse-phase current is generated in the armature current. As a result, when a layer short circuit occurs in the armature winding, an imbalance can occur in the amplitude of the U-phase, V-phase, and W-phase.

[0096] For example, consider a case where a layer short circuit in the electric motor EM causes only the U-phase current to change by a factor of α (α ≠ 1) among the U-phase, V-phase, and W-phase currents. In this case, the U-phase current value I u , V-phase current value I v , and the W-phase current value I v is the normal amplitude I of the electric motor EM m Using the above, it is expressed by the following equations (2) to (4).

[0097]

number

[0098] For equations (2) to (4), a three-phase to two-phase transformation is performed by relative transformation from the three phases of U, V, and W to two phases of the αβ stationary coordinate system, and the current value I α , and the current value I on the β axis β is expressed by the following equations (5) and (6).

[0099]

number

[0100] By performing a rotational coordinate transformation on equations (5) and (6), the d-axis current value I d , and the q-axis current value I q is expressed by the following equations (7) and (8).

[0101]

number

[0102] As described above, from equations (7) and (8), when an amplitude imbalance of the phase current occurs, the current values ​​I d ,I q It can be seen that a cos2θ component and a sin2θ component, i.e., a component twice the electrical angle θ, are generated in the instantaneous active power P and the instantaneous reactive power Q. Therefore, the diagnostic device 75 can diagnose a layer short circuit in the electric motor EM by using the component twice the electrical angle θ in the instantaneous active power P and the instantaneous reactive power Q.

[0103] Specifically, the specific frequency component extraction unit 751 extracts a frequency corresponding to twice the electrical angle θ (i.e., 2θ) as the specific frequency, specifically, a component twice the rotation frequency ω (2ω).The feature amount acquisition unit 752 then extracts a feature amount for the component twice the rotation frequency ω.This allows the diagnosis unit 753 to diagnose a layer short circuit in the electric motor EM.

[0104] [Specific examples of differences in the degree of abnormality that appears in current and voltage] Next, specific examples of differences in the degree of abnormality appearing in the current and voltage of the electric motor EM depending on various conditions of the electric motor EM will be described with reference to Figures 4 to 7. Specifically, specific examples of differences in the degree of abnormality appearing in the amplitude value of the double component of the electrical angle θ of the current and voltage of the electric motor EM, which are caused by a layer short circuit in the electric motor EM, will be described.

[0105] Figures 4 and 5 are diagrams showing a first example of the results of a simulation of the operating state of electric motor EM when an abnormality occurs. Figures 6 and 7 are diagrams showing a second example of the results of a simulation of the operating state of electric motor EM when an abnormality occurs. Specifically, Figures 4 and 5 show the results of a simulation of the operating state of electric motor EM when a layer short circuit occurs in electric motor EM when the PI control gain (specifically, proportional gain) in vector control is relatively small. On the other hand, Figures 6 and 7 show the results of a simulation of the operating state of electric motor EM when a layer short circuit occurs in electric motor EM when the PI control gain (specifically, proportional gain) in vector control is relatively large.

[0106] 4 includes FIGS. 4A to 4D. FIG. 4A shows the time variations of the phase currents of the U, V, and W phases. FIG. 4A includes a time waveform 401 of the U-phase current value Iu (detected value), a time waveform 402 of the V-phase current value Iv (detected value), and a time waveform 403 of the W-phase current value Iw (detected value). FIG. 4B shows the time variations of the d-axis and q-axis current values ​​I d ,I q (detected value) over time. Figure 4B shows the current value I d The time waveform 411 and the q-axis current value I q 4C includes a time waveform 412 of the d-axis and q-axis voltage values ​​V d ,V q Figure 4C shows the time change of the d-axis voltage value V d The time waveform 421 and the q-axis voltage value V q 4D shows the changes over time of the instantaneous active power P and the instantaneous reactive power Q. FIG. 4D includes a time waveform 431 of the instantaneous active power P and a time waveform 432 of the instantaneous reactive power Q.

[0107] Figure 5 shows the d-axis current value I d , and the q-axis current value I q The average value of the amplitude of the double component of each electrical angle θ, and the d-axis voltage value V d and q-axis voltage value V q 10 is a bar graph showing the average value of the amplitude of the double component of each electrical angle θ of instantaneous active power P and instantaneous reactive power Q, as well as the average value of the double component of each electrical angle θ of instantaneous active power P and instantaneous reactive power Q.

[0108] FIG. 6 includes FIGS. 6A to 6D. FIG. 6A shows the time variations of the phase currents of the U, V, and W phases. FIG. 6A includes a time waveform 601 of the U-phase current value Iu (detected value), a time waveform 602 of the V-phase current value Iv (detected value), and a time waveform 603 of the W-phase current value Iw (detected value). FIG. 6B shows the time variations of the d-axis and q-axis current values ​​I d ,I q Figure 6B shows the time change of the current value I d The time waveform 611 and the q-axis current value I q 6C includes a time waveform 612 of the d-axis and q-axis voltage values ​​V d ,V q Figure 6C shows the time change of the d-axis voltage value V d The time waveform 621 and the q-axis voltage value V q 6D shows the time variations of the instantaneous active power P and the instantaneous reactive power Q. FIG. 6D includes a time waveform 631 of the instantaneous active power P and a time waveform 632 of the instantaneous reactive power Q.

[0109] Figure 7 shows the d-axis current value I d , and the q-axis current value I q The average value of the amplitude of the double component of each electrical angle θ, and the d-axis voltage value V d and q-axis voltage value V q 10 is a bar graph showing the average value of the amplitude of the double component of each electrical angle θ of instantaneous active power P and instantaneous reactive power Q, as well as the average value of the double component of each electrical angle θ of instantaneous active power P and instantaneous reactive power Q.

[0110] As shown in FIG. 4A, when the control gain is relatively small, the degree of imbalance in the amplitude of the phase currents caused by a layer short in the electric motor EM is relatively large. As a result, as shown in FIG. 4B and FIG. 5, the d-axis current value I d , and the q-axis current value I q 4C and 5, when the control gain is relatively small, the amplitude of the double component of the electrical angle θ at the d-axis voltage value V d and q-axis voltage value V qTherefore, when the control gain is relatively small, the amplitude of the double component of the electrical angle θ at the d-axis voltage value V d and q-axis voltage value V q The d-axis current value I d , and the q-axis current value I q The characteristic of a rare short circuit (i.e., an abnormality caused by the occurrence of a rare short circuit) appears relatively significantly in the characteristic quantity related to the double component of the electrical angle θ.

[0111] On the other hand, as shown in FIG. 6A, when the control gain is relatively large, the degree of imbalance in the amplitude of the phase currents caused by a layer short circuit in the electric motor EM is relatively small. As a result, as shown in FIG. 6B and FIG. 7, the d-axis current value I d , and the q-axis current value I q 6C and 7, when the control gain is relatively large, the amplitude of the double component of the electrical angle θ at the d-axis voltage value V d and q-axis voltage value V q Therefore, when the control gain is relatively large, the amplitude of the double component of the electrical angle θ at the d-axis current value I d , and the q-axis current value I q The d-axis voltage value V d and q-axis voltage value V q The characteristic of a rare short circuit (i.e., an abnormality caused by the occurrence of a rare short circuit) appears relatively significantly in the characteristic quantity related to the double component of the electrical angle θ.

[0112] In this way, the d-axis current value I d , and the q-axis current value I q The feature quantities related to the d-axis voltage value V d and q-axis voltage value V q The degree of the layer short characteristic that appears in the characteristic quantity related to changes. Therefore, the d-axis current value I d , and the q-axis current value I q The feature quantities related to the d-axis voltage value V d and q-axis voltage value V qIf only one of the feature quantities is used, it may not be possible to properly diagnose a layer short in the electric motor EM.

[0113] On the other hand, as shown in Figs. 4D, 5, 6D, and 7, the amplitudes of the instantaneous active power P and the instantaneous reactive power Q are relatively large regardless of the magnitude of the control gain. d , and the q-axis current value I q The feature quantities related to the d-axis voltage value V d and q-axis voltage value V q This is because the characteristics of the change in the feature quantities related to the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM are opposite to each other. Therefore, by using the feature quantities related to the double component of the electrical angle θ in the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM, the diagnosing device 75 can appropriately diagnose a layer short circuit in the electric motor EM regardless of the control gain.

[0114] However, the degree of the characteristics of a layer short circuit in the electric motor EM, which appears in the characteristic quantities (in this example, amplitude) related to the double component of the electrical angle θ in the instantaneous active power P and instantaneous reactive power Q of the electric motor EM, may change depending on the control gain. Therefore, the diagnosing unit 753 adjusts the diagnostic criteria (for example, the above-mentioned threshold value) related to the characteristic quantities related to the double component of the electrical angle θ in the instantaneous active power P and instantaneous reactive power Q of the electric motor EM depending on the setting state of the control gain of the current adjusting unit 704. This enables the diagnosing device 75 to more appropriately diagnose a layer short circuit in the electric motor EM.

[0115] [Diagnosis processing for motor abnormalities] Next, with reference to FIG. 8, the diagnosis process for diagnosing an abnormality in the electric motor EM by the diagnosing device 75 will be described.

[0116] FIG. 8 is a flowchart showing an example of a process for diagnosing an abnormality in the electric motor EM by the diagnosing device 75. In FIG.

[0117] This flowchart is repeatedly executed at regular intervals Ts during operation of the power conversion device 100 (the period from power-on to power-off), for example.

[0118] In this flowchart, an integrating timer (time t) and an abnormality status are used. The time t and the abnormality status are initialized to a zero (0) state and a clear state, respectively, when the power conversion device 100 is powered on.

[0119] As shown in FIG. 8, in step S102, the calculation unit 750 calculates the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM.

[0120] When the process of step S102 is completed, the diagnostic device 75 proceeds to step S104.

[0121] In step S104, the specific frequency component extractor 751 extracts specific frequency components from the measurement data of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM over a certain period of time, which data is output in step S102.

[0122] When the process of step S104 is completed, the diagnostic device 75 proceeds to step S106.

[0123] In step S106, the feature acquisition unit 752 acquires an amplitude value A as a feature related to an abnormality in the electric motor EM based on the specific frequency components of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM acquired in step S104.

[0124] When the process of step S106 is completed, the diagnostic device 75 proceeds to step S108.

[0125] In step S108, the diagnosis unit 753 determines whether the rotation frequency ω of the electric motor EM is greater than or equal to a predetermined threshold value ω th Determine whether it is greater than (>0). th is defined in advance as the minimum value of the rotation frequency ω of the electric motor EM at which a diagnosis of an abnormality in the electric motor EM can be performed.th If it is greater, proceed to step S110; otherwise, proceed to step S118.

[0126] In step S110, the diagnosis unit 753 calculates the average value (average amplitude value A) of the amplitude values ​​A of the double components of the electrical angle θ of the instantaneous active power P and the instantaneous reactive power Q acquired in step S106. m ) is a predetermined threshold A th Determine whether it is greater than (>0).

[0127] Threshold A th is the average amplitude value A when the electric motor EM is abnormal. m The threshold A corresponds to the minimum value of th is determined in advance through, for example, an experiment or computer simulation that simulates an abnormality in the electric motor EM. th may be adjusted as appropriate according to various conditions of the electric motor EM (for example, control gain).

[0128] The diagnosis unit 753 calculates the average amplitude value A m is threshold A th If it is greater, proceed to step S112; otherwise, proceed to step S118.

[0129] In step S112, the diagnosis unit 753 accumulates the time t. For example, the diagnosis unit 753 accumulates the cycle of the flowchart for the time t (t=t+Ts). Alternatively, the diagnosis unit 753 may accumulate the time t by incrementing the time t as a counter by 1 (t=t+1).

[0130] When the process of step S112 is completed, the diagnostic device 75 proceeds to step S114.

[0131] In step S114, the diagnosis unit 753 determines whether the time t is equal to or smaller than a predetermined threshold t th The diagnosis unit 753 determines whether the time t is greater than the threshold t (>0). th If it is greater, proceed to step S116; otherwise, proceed to step S118.

[0132] threshold t th is the average amplitude value A m is threshold A th This is predefined as the minimum time period for which it can be determined that a greater condition is not occurring temporarily, but is being maintained continuously.

[0133] When the process of step S114 is completed, the diagnostic device 75 proceeds to step S116.

[0134] In step S116, the diagnosis unit 753 diagnoses that there is an abnormality in the electric motor EM and sets an abnormality status. th Larger than the average amplitude value A m is threshold A th The state greater than the threshold t th If the voltage continues to exceed this level, it is diagnosed that there is an abnormality in the electric motor EM.

[0135] The notification unit 754 references the abnormality status data at regular intervals. As a result, when the diagnosis unit 753 diagnoses that there is an abnormality in the electric motor EM, the user can be notified of the abnormality in the electric motor EM via the display unit 80 or the like.

[0136] When the process of step S116 is completed, the diagnostic device 75 ends the process of this flowchart.

[0137] On the other hand, in step S118, the diagnosis unit 753 resets the time t to zero (0).

[0138] When the process of step S118 is completed, diagnostic device 75 proceeds to step S120.

[0139] In step S120, the diagnosis unit 753 diagnoses that the electric motor EM is normal and clears the abnormality status. As a result, when the abnormality status is cleared, the notification unit 754 can determine that there is no abnormality in the electric motor EM (that the electric motor EM is normal). Furthermore, when the abnormality status is cleared from a set state, the notification unit 754 can determine that the abnormality in the electric motor EM has been resolved and can stop notifying the user that there is an abnormality in the electric motor EM.

[0140] When the process of step S120 is completed, the diagnostic device 75 ends the process of this flowchart.

[0141] In this way, the diagnostic device 75 calculates the average amplitude value A of the specific frequency components of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM extracted by the specific frequency component extractor 751. m is threshold A th If the average amplitude value A of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM is larger than the average amplitude value A of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM, the electric motor EM is diagnosed as being abnormal. m It is possible to grasp an abnormal state in which the value is larger than the normal state and diagnose that there is an abnormality in the electric motor EM.

[0142] The diagnostic device 75 also calculates the average amplitude A of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM at a specific frequency. m is threshold A th The state where time t is greater than the threshold t th If the average amplitude value A continues to exceed the value A, the diagnosis device 75 diagnoses that there is an abnormality in the electric motor EM. m is threshold A th The state where the magnitude of the error is greater than the predetermined value can be excluded from the abnormal state of the electric motor EM, and the presence or absence of an abnormality in the electric motor EM can be diagnosed. Therefore, the diagnostic device 75 can suppress erroneous diagnosis and improve the accuracy of the diagnosis of the presence or absence of an abnormality in the electric motor EM.

[0143] [Other embodiments] Next, another embodiment will be described.

[0144] The above-described embodiment may be modified or changed as appropriate. Hereinafter, examples in which the above-described embodiment is modified or changed will be referred to as "modified examples" for convenience.

[0145] For example, in the above-described embodiment, the functions of the diagnostic device 75 may be realized in a distributed manner by a plurality of diagnostic devices mounted on the power conversion device 100.

[0146] Also, in the above-described embodiment, the functionality of the diagnostic device 75 may be integrated into the control circuit 70 .

[0147] In the above-described embodiment and modified examples, the function of the calculation unit 750 may be transferred to an outside of the diagnostic device 75. For example, the function of the calculation unit 750 is transferred to the control circuit 70. Furthermore, for example, when the function of the diagnostic device 75 is transferred to an outside of the power conversion device 100, the function of the calculation unit 750 is transferred to an information processing device (for example, a microcomputer) built into the power conversion device 100 and different from the control circuit 70.

[0148] Furthermore, in addition to the function of the calculation unit 750, the function of the specific frequency component extraction unit 751 may be transferred to an outside of the diagnostic device 75. For example, the function of the specific frequency component extraction unit 751 is transferred to the control circuit 70. Furthermore, for example, when the function of the diagnostic device 75 is transferred to an outside of the power conversion device 100, the function of the specific frequency component extraction unit 751 is transferred to an information processing device (for example, a microcomputer) built into the power conversion device 100 and different from the control circuit 70.

[0149] Furthermore, in addition to the functions of the calculation unit 750 and the specific frequency component extraction unit 751, the function of the feature amount acquisition unit 752 may also be transferred to an outside of the diagnostic device 75. For example, the function of the feature amount acquisition unit 752 is transferred to the control circuit 70. Furthermore, for example, when the function of the diagnostic device 75 is transferred to an outside of the power conversion device 100, the function of the feature amount acquisition unit 752 is transferred to an information processing device (for example, a microcomputer) built into the power conversion device 100 and different from the control circuit 70.

[0150] Furthermore, in the above-described embodiments and variations, the diagnostic device 75 may diagnose types of abnormalities other than a layer short in the electric motor EM using N-fold components (N: an integer of 3 or more) other than the double component of the electrical angle of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM.

[0151] In the above-described embodiment and modified examples, the diagnostic device 75 may use only one of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM as a feature quantity related to an abnormality in the electric motor EM. In this case, the calculation unit 750 calculates and outputs only one of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM.

[0152] In the above-described embodiment and modified examples, the calculation unit 750 calculates the instantaneous active power P and the instantaneous reactive power Q based on the detected current value and the command value of the voltage of the electric motor EM, but the command value of the current may be used instead of the detected current value, and the detected voltage value may be used instead of the command value of the voltage. In other words, the calculation unit 750 can calculate the instantaneous active power P and the instantaneous reactive power Q based on the detected values ​​of both the current and voltage of the electric motor EM, the command values ​​of both, or a combination of one detected value and the command value of the other.

[0153] [Effect] Next, the operation of the diagnostic device, power conversion device, and diagnostic method according to this embodiment will be described.

[0154] In a first aspect of this embodiment, a diagnostic device diagnoses an abnormality in an electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor. The electric motor is, for example, the electric motor EM described above.

[0155] In addition, in a first aspect of this embodiment, the power conversion device may include a main circuit and a diagnostic unit. The power conversion device is, for example, the power conversion device 100 described above. The main circuit unit is, for example, the main circuit 100MC described above. The diagnostic unit is, for example, the diagnostic device 75 described above. Specifically, the main circuit unit may drive the electric motor by converting externally supplied power into predetermined power and outputting it. The diagnostic unit may then diagnose an abnormality in the electric motor based on measurement data of at least one of the instantaneous active power and instantaneous reactive power of the electric motor.

[0156] In addition, a first aspect of the present embodiment may provide a diagnostic method executed by a diagnostic device. Specifically, in the diagnostic method of this aspect, the diagnostic device may diagnose an abnormality in an electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor.

[0157] For example, when diagnosing an abnormality in a motor using only either the current or voltage of the motor, the degree of abnormality that appears in the current or voltage and indicates an abnormality in the motor may vary depending on various conditions, which may make it impossible to properly diagnose the abnormality in the motor.

[0158] In contrast, in this aspect, a diagnostic device or a diagnostic unit (hereinafter referred to as "diagnostic device, etc.") can diagnose abnormalities in the motor using the instantaneous active power and instantaneous reactive power of the motor. Therefore, the diagnostic device can appropriately diagnose abnormalities in the motor. This is because abnormalities indicative of abnormalities in the motor often appear more clearly in either the current or voltage of the motor than in the other, and relatively large abnormalities appear in the instantaneous active power and instantaneous reactive power obtained by multiplying the current and voltage, regardless of various conditions.

[0159] In addition, in a second aspect of this embodiment, based on the first aspect described above, a diagnostic device or the like may diagnose abnormalities in the electric motor based on specific frequency components of at least one of the instantaneous active power and the instantaneous reactive power.

[0160] This allows the diagnostic device, etc. to diagnose motor abnormalities using specific frequency components of the motor's instantaneous active power and instantaneous reactive power, which may cause abnormalities in the current or voltage that indicate an abnormality in the motor, depending on the type of abnormality being diagnosed.

[0161] In addition, in a third aspect of this embodiment, based on the second aspect described above, the specific frequency component may be a component that is an integer multiple of an electrical angle.

[0162] This allows the diagnostic device or the like to diagnose types of motor abnormalities that may cause abnormalities in components that are integer multiples of the electrical angle in the current or voltage of the motor.

[0163] In a fourth aspect of the present embodiment, based on the third aspect described above, the specific frequency component may have a frequency twice the electrical angle, and the abnormality in the electric motor may be a layer short circuit in the electric motor.

[0164] This allows the diagnostic device or the like to diagnose a rare short in the motor, which can cause an abnormality in the component twice the electrical angle, among the types of abnormalities in the motor.

[0165] In a fifth aspect of the present embodiment, based on any one of the second to fourth aspects, the electric motor operates in accordance with predetermined control by a control device. The predetermined control may be, for example, the vector control described above. The predetermined control may suppress the specific frequency component of the electric motor current.

[0166] As a result, even if, for example, a specific frequency component of the current of the motor is suppressed by a predetermined control of the motor, the diagnostic device or the like can appropriately diagnose abnormalities in the motor by using the instantaneous active power and instantaneous reactive power of the motor.Furthermore, even if, for example, the degree to which a specific frequency component of the current is suppressed changes depending on the control gain in the predetermined control, the diagnostic device or the like can appropriately diagnose abnormalities in the motor by using the instantaneous active power and instantaneous reactive power of the motor.

[0167] In a sixth aspect of the present embodiment, based on any one of the first to fifth aspects described above, the diagnostic device may operate in accordance with predetermined control by the control device. The diagnostic device may change a diagnostic criterion in accordance with a control gain in the predetermined control. The diagnostic criterion is, for example, the threshold value described above.

[0168] This allows the diagnostic device or the like to appropriately diagnose abnormalities related to abnormalities in the motor in accordance with the degree of suppression of specific frequency components of the current, which changes depending on the control gain, for example.

[0169] In addition, in a seventh aspect of this embodiment, assuming any one of the first to sixth aspects described above, measurement data of at least one of the instantaneous active power and the instantaneous reactive power may be obtained based on the d-axis and q-axis components on the rotating coordinate system or the α-axis and β-axis components on the stationary coordinate system in the measurement data of the current and voltage of the motor.

[0170] This allows the diagnostic device or the like to acquire measurement data of instantaneous active power and instantaneous reactive power.

[0171] In addition, in an eighth aspect of this embodiment, assuming any one of the first to seventh aspects described above, measurement data of at least one of the instantaneous active power and the instantaneous reactive power may be obtained based on a combination of the detected values ​​of the current and voltage of the motor and a control command value.

[0172] This allows the diagnostic device or the like to acquire measurement data of instantaneous active power and instantaneous reactive power.

[0173] 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]

[0174] 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 75 Diagnostic Equipment 80 Display section 90 Communications Department 100 Power conversion device 100MC main circuit 150 Rotational status sensor 200 Management device 300 Terminal Device 701 Speed ​​adjustment section 702 Current detection unit 703 Vector conversion unit 704 Current adjustment section 705 Vector Inverse Transformation Unit 706 Voltage Compensation Unit 707 Gate signal output section 750 Arithmetic unit 751 Specific frequency component extraction unit 752 Feature Acquisition Unit 753 Diagnostic Department 754 Notification Department A amplitude value Am Average amplitude value Ath threshold EL organic EM electric motor NL Negative Line P instantaneous active power PL positive line PS commercial power supply Q instantaneous reactive power SD rectifier diode SW Semiconductor switch

Claims

1. Diagnosing an abnormality in the electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor; Diagnostic equipment.

2. performing a diagnosis of an abnormality in the electric motor based on a specific frequency component of at least one of the instantaneous active power and the instantaneous reactive power; The diagnostic device of claim 1 .

3. The specific frequency component is an integer multiple of an electrical angle. The diagnostic device of claim 2 .

4. the specific frequency component has a frequency twice the electrical angle, The abnormality of the motor is a layer short circuit of the motor. The diagnostic device of claim 3.

5. The electric motor operates in accordance with predetermined control by a control device, The predetermined control suppresses the specific frequency component of the current of the motor. A diagnostic device according to any one of claims 2 to 4.

6. The electric motor operates in accordance with predetermined control by a control device, changing the diagnostic criterion according to a control gain in the predetermined control; A diagnostic device according to any one of claims 1 to 4.

7. Measurement data of at least one of the instantaneous active power and the instantaneous reactive power is obtained based on d-axis and q-axis components on a rotating coordinate system or α-axis and β-axis components on a stationary coordinate system in the measurement data of the current and voltage of the electric motor. A diagnostic device according to any one of claims 1 to 4.

8. measurement data of at least one of the instantaneous active power and the instantaneous reactive power is obtained based on a combination of the detected values ​​of the current and voltage of the electric motor and a control command value; A diagnostic device according to any one of claims 1 to 4.

9. a main circuit section that converts externally supplied power into a predetermined power and outputs the converted power to drive the electric motor; a diagnostic unit that diagnoses an abnormality in the electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor, Power conversion device.

10. a diagnostic device for diagnosing an abnormality in the electric motor based on measurement data of at least one of instantaneous active power and instantaneous reactive power of the electric motor; Diagnostic methods.

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