DIAGNOSTIC DEVICE, POWER CONVERTER AND DIAGNOSTIC PROCEDURES

Abstract

A diagnostic device is set up to diagnose an anomaly of an electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The disclosures herein relate to diagnostic devices and the like. 2. Description of the state of the art

[0002] A technology for diagnosing, for example, an anomaly of an electric motor based on a voltage or current of the electric motor is known (see patent literature (PTL) 1). LIST OF QUOTE PATENT LITERATURE

[0003] [PTL 1] Japanese Disclosure Patent Publication No. 2022-140897 Brief description of the invention problem that the invention is intended to solve.

[0004] However, there are cases where the degree of an electric motor anomaly, manifested in characteristics related to current or voltage, changes depending on various operating conditions. Therefore, it may not be possible to make a correct diagnosis of the electric motor anomaly.

[0005] Therefore, in view of the aforementioned problem, one object of the present invention is to provide a technology capable of correctly diagnosing the anomaly of the electric motor. MEANS TO SOLVE THE PROBLEM

[0006] A diagnostic device is set up to diagnose an anomaly of an electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor.

[0007] A power converter includes a main circuit unit configured to convert externally supplied power into a predetermined power output for use in driving an electric motor, and a diagnostic device or unit configured to diagnose an anomaly of the electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor.

[0008] A diagnostic procedure includes diagnosing, by means of a diagnostic device, an anomaly of an electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor. EFFECTS OF INVENTION

[0009] According to the embodiments described above, it is possible to adequately diagnose the anomaly of the electric motor. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a drawing illustrating an example of a diagnostic system configuration; Fig. Figure 2 is a functional block diagram illustrating an example of a functional configuration of a control circuit; Fig. Figure 3 is a functional block diagram illustrating an example of a functional configuration of a diagnostic device; Fig. Figure 4 is a drawing illustrating a first example of a simulation result of an operating state of an electric motor when an anomaly occurs; Fig. Figure 5 is a drawing illustrating the first example of the simulation result of the operating state of the electric motor when the anomaly occurs; Fig. Figure 6 is a drawing illustrating a second example of a simulation result of an operating state of the electric motor when an anomaly occurs; Fig. Figure 7 is a drawing illustrating the second example of the simulation result of the operating state of the electric motor when the anomaly occurs; and Fig. Figure 8 is a flowchart that schematically illustrates an example of a process for diagnosing an electric motor anomaly. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0010] In the following, embodiments of the present disclosure are described with reference to the accompanying drawings. [CONFIGURATION OF DIAGNOSTIC SYSTEM]

[0011] A configuration of a diagnostic system 1 according to the present embodiment is described with reference to Fig. 1 described.

[0012] Fig. Figure 1 is a drawing illustrating an example of the configuration of the diagnostic system 1 according to the present embodiment.

[0013] As in Fig. As shown in Figure 1, the diagnostic system 1 includes an electric motor EM, a power converter 100, a rotation state sensor 150, a management device 200 and a terminal device 300.

[0014] The diagnostic system 1 diagnoses an anomaly of the electric motor EM in the power converter 100 (in particular a diagnostic device 75 described below).

[0015] The electric motor EM anomaly to be diagnosed by diagnostic system 1 includes an anomaly caused by a temporary cause and an anomaly caused by a cumulative cause related to electric motor EM (i.e., a deterioration anomaly). The anomaly to be diagnosed by diagnostic system 1 also includes a mechanical anomaly and an electrical anomaly. For example, the mechanical anomaly of electric motor EM to be diagnosed by diagnostic system 1 includes a bearing anomaly. The electrical anomaly of electric motor EM to be diagnosed by diagnostic system 1 includes, for example, insulation deterioration (short circuit between layers) of electric motor EM.

[0016] The diagnosis of an electric motor EM anomaly includes, for example, a diagnosis of the presence or absence of an anomaly in the electric motor EM. The diagnosis of an electric motor EM anomaly may also include a diagnosis of the presence or absence of any indication of an anomaly in the electric motor EM. The diagnosis of an electric motor EM anomaly may also include a diagnosis of the degree of the anomaly in the electric motor EM.

[0017] The electric motor EM, for example, powers production equipment and mechanical devices installed in a factory. The electric motor EM is, for example, an AC motor such as an induction motor or a synchronous motor.

[0018] The power converter 100 converts three-phase AC power (e.g. R-phase, S-phase and T-phase) input from a commercial power supply PS into three-phase AC power (e.g. U-phase, V-phase and W-phase) with a predetermined voltage and frequency to drive the electric motor EM.

[0019] The power converter 100 contains a main circuit 100MC, a current sensor 40, a voltage sensor 50, a gate driver circuit 60, a control circuit 70, the diagnostic device 75, a display unit 80 and a communication unit 90.

[0020] The main circuit 100MC contains a rectifier circuit 10, a smoothing circuit 20 and a converter circuit 30.

[0021] The rectifier circuit 10 is configured to rectify three-phase AC power input from the 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 one end of a negative line NL, and can output the DC power to the smoothing circuit 20 through the positive line PL and the negative line NL.

[0022] For example, in Fig. As shown in Figure 1, rectifier circuit 10 contains six rectifier diodes SD and is a bridge-type full-wave rectifier circuit in which three sets of series connections of two rectifier diodes SD, contained in the upper and lower arms, are connected in parallel. In this case, the input lines of the R-phase, S-phase, and T-phase are each connected to the midpoints of the three sets of upper and lower arms.

[0023] The smoothing circuit 20 reduces and smooths out pulsation of the direct current output by the rectifier circuit 10 and of the direct current regenerated by the converter circuit 30.

[0024] For example, in Fig. As shown in Figure 1, the smoothing circuit 20 contains a smoothing capacitor 21.

[0025] The smoothing capacitor 21 can be provided to electrically connect the positive line PL and the negative line NL in parallel with the rectifier circuit 10 and the converter circuit 30.

[0026] The smoothing capacitor 21 smooths the DC power output by the rectifier circuit 10 and the DC current output by the inverter circuit 30 (regeneration) as charging and discharging are repeated appropriately.

[0027] For example, in Fig. As shown in Figure 1, there is a smoothing capacitor 21. Multiple smoothing capacitors 21 can be arranged, and these multiple smoothing capacitors 21 can be connected in parallel or in series between the positive line PL and the negative line NL. The multiple smoothing capacitors 21 can be configured such that several series connections of two or more smoothing capacitors are connected in parallel between the positive line PL and the negative line NL.

[0028] The smoothing circuit 20 can also contain a reactor.

[0029] The reactor is provided, for example, in the positive line PL between the rectifier circuit 10 and the smoothing capacitor 21.

[0030] The reactor smooths the DC power output by rectifier circuit 10 and the DC current output by converter circuit 30 (regeneration), while adequately generating a voltage to prevent changes in current.

[0031] The positive and negative input units of the inverter circuit 30 are connected to the other ends of the positive line PL and the negative line NL. The inverter circuit 30 converts the DC power supplied by the smoothing circuit 20 into three-phase AC (i.e., U-phase, V-phase, and W-phase) with the predetermined frequency and voltage by means of a switching operation of a semiconductor switch SW and outputs this to the electric motor EM.

[0032] 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 made, for example, of silicon (Si) as its main material. The semiconductor switch SW can also be made of a wide-bandgap semiconductor material as its main material. Examples of wide-bandgap semiconductor materials include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga₂O₃), or carbon (diamond: C).

[0033] For example, in Fig. As shown in Figure 1, the inverter circuit 30 contains six semiconductor switches SW. Specifically, the inverter circuit 30 can include a bridge circuit in which three sets of series connections (switch legs) of two semiconductor switches SW, contained in upper and lower arms, are connected in parallel between the positive line PL and the negative line NL. In this case, the inverter circuit 30 outputs three-phase alternating current through three output lines routed from the connection points of the three sets of upper and lower arms. Furthermore, the six semiconductor switches SW can be connected in parallel with a flyback diode.

[0034] The current sensor 40 detects the current of each of the three-phase output lines of the power converter 100, that is, the current of each of the three phases of the electric motor EM. The current sensor 40 detects the current using, for example, a Hall effect sensor, a shunt resistor, a magnetoresistive element, a flux gate, or the like, and uses an analog-to-digital converter (ADC) to acquire a measured value (digital value) of the current. The current sensor 40 outputs a signal corresponding to the measured value of the current of each of the three phases of the electric motor EM, and this output signal is fed into the control circuit 70.

[0035] The current sensor 40 can only detect the current of any two phases from the three-phase output lines of the power converter 100. In this case, the control circuit 70 can derive (calculate) the current value of the remaining one phase from the detected current value of the two phases. The control circuit 70 can derive (in particular, calculate) the current value of the output line of the three phases of the power converter 100, for example, based on the current value of the DC connection (positive line PL or negative line NL) and the switching pattern of the semiconductor switches SW. In this case, the control circuit 70 can derive (in particular, calculate) the current value of the DC connection based on the output of the voltage sensor 50.

[0036] The voltage sensor 50 detects the voltage (voltage of the DC connection) between the positive line PL and the negative line NL of the power converter 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 received in the control circuit 70.

[0037] The gate driver circuit 60 outputs a drive signal to switch (ON / OFF) the six semiconductor switches SW of the inverter circuit 30 to the respective gate terminals of the six semiconductor switches SW, which are controlled by the control circuit 70.

[0038] The control circuit 70 controls the power converter 100.

[0039] The functions of the control circuit 70 can be achieved by any hardware or any combination of hardware and software. The control circuit 70 includes a computer containing a CPU (Central Processing Unit), a memory device, an auxiliary memory device, and an interface device. The memory device is, for example, SRAM (Static Random Access Memory). The auxiliary memory device is, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory) 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 control circuit 70 can achieve various functions by loading a program installed in the auxiliary memory device into the main memory and executing it on the CPU. The control circuit 70 can also import and install a program from a storage medium via its external interface and import and install a program from other devices via its communication interface.

[0040] For example, the control circuit 70 controls the inverter circuit 30 so that the electric motor EM operates under predetermined operating conditions, and drives the electric motor EM under predetermined operating conditions.

[0041] The functions of the control circuit 70 can also be distributed and achieved by several control circuits mounted on the power converter 100.

[0042] The diagnostic device 75 diagnoses the anomaly of the electric motor EM.

[0043] The functions of the Diagnostic Device 75 can be achieved by any hardware or any combination of hardware and software. The Diagnostic Device 75 includes a computer with a CPU, a memory device, an auxiliary memory device, and an interface device. The memory device is, for example, SRAM. The auxiliary memory 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 achieve various functions by loading programs installed in the auxiliary memory device into the memory device and executing them on the CPU.The diagnostic device 75 can also import and install programs from the recording medium through the external interface and import and install programs from other devices through the communication interface.

[0044] The display unit 80 shows a user (e.g., a worker in a factory where a production plant or a mechanical plant driven by an electric motor EM is installed) information about the power converter 100, which is controlled by the control circuit 70 and the diagnostic device 75. The display unit 80 includes, for example, a warning light, an electrical indicator panel, a liquid crystal display, an organic EL (electroluminescent) display, and the like.

[0045] The communication unit 90 communicates with an external device of the power converter 100 via a predetermined communication line.

[0046] The predetermined communication link can be, for example, a 1:1 communication link. Furthermore, the predetermined communication link can be, for example, a local area network (LAN), such as a field network, set up within a facility (factory) where production equipment, mechanical systems, etc., driven by an electric motor (EM) are installed. The local network can be wired, wireless, or both. Additionally, the predetermined communication link can include, for example, a wide area network (WAN) outside of a facility (factory) where production equipment, mechanical systems, or the like, driven by an electric motor (EM), are installed. The wide area network can include, for example, a mobile communication network terminating at a base station, a satellite communication network utilizing a communication satellite, an internet network, or the like.Additionally, the predetermined communication line may, for example, include a short-range communication line based on a predetermined wireless communication standard such as Bluetooth (registered trademark) or WiFi.

[0047] A function of the communication unit 90 can be integrated into the control circuit 70 or the diagnostic device 75 as a function of the interface device.

[0048] The rotational state sensor 150 is attached to the electric motor EM and detects a physical quantity representing the rotational state of the electric motor EM, such as its position and speed. The rotational state sensor 150 can be, for example, an optical or magnetic encoder. The rotational state sensor 150 outputs a signal corresponding to the detected speed value of the electric motor EM, and this output signal is received by the control circuit 70 of the power converter 100. Thus, the control circuit 70 can detect the magnetic pole position and the rotational speed of a rotor in the electric motor EM based on the signal detected by the rotational state sensor 150.

[0049] The management device 200 is located outside the power converter 100. The management device 200 is communicatively connected to the power converter 100 as a superior device of the power converter 100 and manages the power converter 100 and the electric motor EM.

[0050] The management device 200, for example, obtains data relating to the states of the power converter 100 and the electric motor EM from the power converter 100 and performs processing related to a monitoring function of the states of the power converter 100 and the electric motor EM. Additionally, the management device 200 performs processing related to an interface function, such as communication between the power converter 100 and users like workers and managers of the factory where the power converter 100 and the electric motor EM are installed. Specifically, the management device 200 can perform processing to provide information relating to the electric motor EM and the power converter 100, and can receive input from the user and transmit it to the power converter 100.

[0051] The Management Device 200, for example, is an edge controller such as a PLC (Programmable Logic Controller) for managing field devices, including the Power Converter 100, in the factory where mechanical devices and production equipment driven by the electric motor EM are installed. The Management Device 200 is, for example, an end device for managing the factory's mechanical and production equipment. The management end device can be, for example, a stationary computer terminal such as a desktop PC (personal computer) installed in a factory office, and the like. The management end device can be, for example, a portable end device (e.g., mobile terminal) such as a tablet terminal, a smartphone, or a laptop PC that can be carried by the factory manager or worker. The Management Device 200 is, for example, a server device.The server equipment can be, for example, an on-premises server or a cloud server installed remotely at the factory where a production plant or a mechanical system driven by an electric motor (EM) is located. Additionally, the server equipment can be an edge server installed on or near the factory premises or similar location where a production plant or a mechanical system driven by an electric motor (EM) is located.

[0052] The functions of the Management Device 200 can be achieved through any hardware or any combination of hardware and software. For example, the Management Device 200 primarily consists of a computer containing a CPU, a memory device, an auxiliary storage device, a high-speed computing device, and an interface device. The Management Device 200 can include user interface devices such as an input device and a display device. The memory device contains, for example, SRAM and DRAM (Dynamic Random Access Memory). The auxiliary storage device contains, for example, HDD (Hard Disk Drive), SSD (Solid State Drive), EEPROM, and flash memory.The high-speed computing device includes, for example, a GPU (Graphics Processing Unit), an ASIC (Application-Specific Integrated Circuit), and an FPGA (Field-Programmable Gate Array). 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 perform various functions by loading programs installed in the auxiliary storage device into the storage device and executing them on the CPU. The Management Device 200 can import and install programs from a recording medium through an external interface or import and install programs from other devices through a communication interface.The input device includes, for example, a keyboard, a mouse, a touch panel, and the like. The display device includes, for example, a liquid crystal display, organic EL display, and the like.

[0053] The terminal 300 is a user terminal located outside the power converter 100 and used by the user of diagnostic system 1. The user of diagnostic system 1 is, for example, a manager or worker in a factory where a production plant or mechanical equipment driven by the electric motor EM is installed. The terminal 300 provides the user with various information relating to the states of the power converter 100 and the electric motor EM, or it accepts various inputs from the user and transmits them to the power converter 100. The terminal 300 can obtain information relating to the electric motor EM and the power converter 100 via the management device 200, or it can obtain such information directly from the power converter 100.Similarly, the terminal device can transmit 300 different inputs from the user to the power converter 100 via the management device 200, or transmit inputs directly from the user to the power converter 100.

[0054] The terminal 300 can be, for example, a stationary terminal such as a desktop PC, or a portable terminal such as a smartphone, tablet terminal or laptop PC.

[0055] The functions of the Terminal 300 can be achieved through any hardware or combinations of any hardware and software. For example, the Terminal 300 primarily consists of user interface devices such as a CPU, a storage device, an auxiliary storage device, a computer containing an interface device, an input device, and a display device. The storage device contains, for example, SRAM and DRAM. The auxiliary storage device contains, for example, HDD, SSD, EEPROM, flash memory, and the like. The interface device contains, for example, an external interface for connecting to an external recording medium and a communication interface for communicating with other devices. The Terminal 300 can achieve various functions by loading programs installed in the auxiliary storage device into the storage device and executing them on the CPU.The terminal 300 can also import and install programs from a recording medium via an external interface and import and install programs from other devices via a communication interface. The input device includes, for example, a push button, a keyboard, a mouse, and a touch panel. The display device includes, for example, a liquid crystal display, an organic EL display, and the like.

[0056] It should be noted that at least one of the management device 200 and the terminal device 300 can be omitted. [FUNCTIONAL CONFIGURATION OF THE CONTROL CIRCUIT]

[0057] The functional configuration of the control circuit 70 according to the present embodiment is then described with reference to Fig. 2 described.

[0058] Fig. Figure 2 is a functional block diagram illustrating an example of a functional configuration of the control circuit 70.

[0059] As in Fig. As shown in Figure 2, the control circuit 70 includes as functional units a speed adjustment unit 701, a current sensing unit 702, a vector conversion unit 703, a current matching unit 704, a vector inverse conversion unit 705, a voltage compensation unit 706 and a gate signal output unit 707.

[0060] Based on a command value (hereinafter referred to as the "speed command value") of the rotational speed of the electric motor EM and a detected value (hereinafter referred to as the "speed detection value") of the rotational speed of the electric motor EM, the speed control unit 701 outputs a control command value (hereinafter referred to as the "current command value") that relates to the current of the electric motor EM in order to minimize deviation. The speed command value is specified according to a predetermined operating condition of the electric motor EM. The speed detection value is obtained based on a signal received from the rotational state sensor 150. In this example, the speed control unit 701 outputs current commands along a d-axis and a q-axis of a rotating dq coordinate system that is fixed relative to the electric motor EM. The speed control unit 701 is, for example, a PI (proportional-integral) control unit.

[0061] When sensorless control is used, for example, an estimated value (speed estimate) of the speed of electric motor EM is used instead of the speed sensing value of electric motor EM. In this case, the rotational state sensor 150 is omitted. If no speed control is used, the speed adjustment unit 701 is omitted. Similarly, if torque control or current control is used, the speed adjustment unit 701 is omitted. In this case, the current command value is generated based on a torque command value in torque control or the current command values ​​of the U-phase, V-phase, and W-phase in current control.

[0062] The current sensing unit 702 obtains and outputs the current sensing 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.

[0063] The vector conversion unit 703 converts the output (current sensing values ​​of U-phase, V-phase and W-phase) of the current sensing unit 702 into the current sensing values ​​of the d-axis and q-axis of the rotating dq coordinate system based on the electric angle θ of the electric motor EM, information about the magnetic pole position and the like, and outputs the converted values.

[0064] The electric angle θ of the electric motor EM is calculated based on the recorded value or the estimated value of the rotational speed of the electric motor EM.

[0065] Based on the deviation between the current command values ​​of the d-axis and q-axis and the current sensing values ​​of the d-axis and q-axis, the 704 current matching unit outputs a command value (voltage command value) that relates to the voltage of the d-axis and q-axis of the electric motor EM in order to minimize the deviation. The 704 current matching unit is, for example, a PI controller.

[0066] The vector inversion unit 705 converts the voltage command values ​​of the d-axis and q-axis into the voltage command values ​​of the U-phase, V-phase and W-phase based on information such as the electric angle θ and the magnetic pole position of the electric motor EM and outputs the converted values.

[0067] The voltage compensation unit 706 corrects the voltage command value of the output (U-phase, V-phase, and W-phase) of the vector inverting conversion unit 705 in order to compensate for the deviation from the voltage command value applied by the power converter 100 (inverter circuit 30) to the electric motor EM. For example, the voltage compensation unit 706 corrects the voltage command value for voltage compensation with respect to the dead time of the inverter circuit 30 and outputs the corrected voltage command values ​​of the U-phase, the V-phase, and the W-phase.

[0068] It should be noted that the voltage compensation unit 706 can be omitted.

[0069] The gate signal output unit 707 generates a signal (gate signal) to apply a voltage to the gate of the semiconductor switch SW in the inverter circuit 30, based on the output (voltage command values ​​of phase U, phase V, and phase W) of the voltage compensation unit 706, and outputs it to the gate driver circuit 60. The gate signal is, for example, a PWM (pulse width modulation) signal. For example, the gate signal output unit 707 includes a comparator corresponding to each of the U, V, and W phases, and the comparator outputs the gate signals of the U, V, and W phases by comparing each of the voltage command values ​​of the U, V, and W phases with a carrier wave. Thus, the control circuit 70 outputs the gate signal to the gate driver circuit 60 to control the semiconductor switch SW of the inverter circuit 30. [FUNCTIONAL CONFIGURATION OF THE DIAGNOSTIC DEVICE]

[0070] The functional configuration of the diagnostic device 75 according to the present embodiment is then described with reference to Fig. 3 described.

[0071] Fig. Figure 3 is a functional block diagram illustrating an example of a functional configuration of a diagnostic device 75.

[0072] As in Fig. As shown in Figure 3, the diagnostic device 75 includes as functional units an arithmetic unit 750, a specific frequency component extraction unit 751, a feature acquisition unit 752, a diagnostic device or unit 753 and a notification unit 754.

[0073] The arithmetic unit 750 calculates the instantaneous active power P and instantaneous reactive power Q of the electric motor EM based on the d-axis and q-axis current values ​​I. d , I q and the d-axis and q-axis voltage values ​​V d , V qof the electric motor EM. The d-axis and q-axis current values ​​I d , I q The current sensing values ​​of the d-axis and q-axis of the electric motor EM, for example, are output by the vector conversion unit 703 of the control circuit 70. The d-axis and q-axis voltage values ​​V d , V q The voltage command values ​​of the d-axis and q-axis of the electric motor EM, for example, are output by the current matching unit 704 of the control circuit 70. If phase voltages of the three phases of the inverter circuit 30 can be detected, the d-axis and q-axis voltage values ​​V can be determined. d , V q The d-axis and q-axis voltage detection values ​​of the electric motor EM are calculated from the detected values ​​of the phase voltages of the three phases.

[0074] For example, the arithmetic unit 750 calculates the instantaneous active power P and the instantaneous reactive power Q using the following equation (1). [Math 1] [PQ]=32[VdVq−VqVd][IdIq]

[0075] Equation (1) corresponds to a case in which the d-axis current value I d and the q-axis current value I q The instantaneous active power P and instantaneous reactive power Q can be calculated by performing a relative conversion from the three phases of the U-phase, V-phase, and W-phase into the two phases of the α-axis and β-axis of the fixed αβ coordinate system. If an absolute conversion is applied instead of the relative conversion, the coefficient of equation (1) is replaced by "1" from "3 / 2". The instantaneous active power P and instantaneous reactive power Q can be calculated based on the α-axis and β-axis current values ​​and the α-axis and β-axis voltage values.

[0076] The Specific Frequency Component Extraction Unit 751 extracts components of each specific frequency from the instantaneous active power P and instantaneous reactive power Q output by the Arithmetic Unit 750. Specifically, the Specific Frequency Component Extraction Unit 751 extracts the components of each specific frequency from time-series data of each specified duration of the instantaneous active power P and instantaneous reactive power Q. For example, the Specific Frequency Component Extraction Unit 751 is a bandpass filter that extracts the components of each specific frequency from the instantaneous active power P and instantaneous reactive power Q.

[0077] The specific frequency component is the frequency component at which features of the anomaly of the type of diagnostic object of the electric motor EM appear with respect to the current and voltage of the electric motor EM. The instantaneous active power P and the instantaneous reactive power Q of the electric motor EM are calculated based on the multiplication of the current and voltage, as shown in equation (1) above. Therefore, the features corresponding to the type of anomaly to be diagnosed, which appear in the specific frequency component of the current and voltage of the electric motor EM, also appear in the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM.

[0078] The specific frequency component is, for example, a frequency with respect to the electric angle θ of the electric motor EM. The frequency with respect to the electric angle θ of the electric motor EM is a frequency corresponding to an integer multiple of the electric angle θ, in particular a frequency corresponding to an integer multiple of the rotational frequency ω. In this case, the specific frequency changes according to the change in the rotational frequency ω. Therefore, the specific frequency component extraction unit 751 can optionally employ a known tracking filter technique (see, for example, the section on the extraction of the specific frequency component disclosed in Japanese Disclosure Patent No. 2024-83207) that is capable of extracting the specific frequency component after the change in the specific frequency.Thus, the specific frequency component extraction unit 751 can extract the specific frequency component with respect to the electric angle θ of the electric motor EM after changing the rotational frequency ω.

[0079] The feature acquisition unit 752 acquires the feature regarding the anomaly of the electric motor EM based on the specific frequency components of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM.

[0080] The feature relating to the anomaly of the electric motor EM is, for example, an amplitude value A of each of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM. For the amplitude value A of each of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM, a waveform counting method is applied to the time series data of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM for a specified duration, and the amplitude value is extracted for each of several waveforms contained in the time series data (see, for example, a waveform counting unit of the Japanese Disclosure Patent, Publication No. 2023-177596).

[0081] The feature relating to the anomaly of the electric motor EM can be the vector length of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM in the rotating dq coordinate system (see, for example, the section on obtaining the feature, which is disclosed in the Japanese Disclosure Patent, Publication No. 2024-83207).

[0082] The diagnostic unit 753 diagnoses the anomaly of the electric motor EM based on the feature acquired by the feature acquisition unit 752. For example, the diagnostic unit 753 diagnoses the anomaly of the electric motor EM based on whether the feature relating to the anomaly of the electric motor EM is equal to or greater than the threshold, or whether it exceeds the threshold.

[0083] For example, the diagnostic unit 753 diagnoses an anomaly in electric motor EM if the amplitudes of both the instantaneous active power P and the instantaneous reactive power Q of electric motor EM are equal to or greater than the predetermined threshold. It is also possible to diagnose an anomaly in electric motor EM if the amplitudes of at least one of the instantaneous active power P and instantaneous reactive power Q of electric motor EM are equal to or greater than the predetermined threshold. Additionally, the diagnostic unit 753 can diagnose that electric motor EM has an anomaly, or shows signs of one, if the average value of the amplitudes of the instantaneous active power P and instantaneous reactive power Q of electric motor EM is equal to or greater than a predetermined threshold.

[0084] The amplitude of the instantaneous active power P or instantaneous reactive power Q of the electric motor EM can, for example, be the amplitude of a waveform obtained by the waveform counting method described above, the average value of the amplitudes of all waveforms, or the maximum value of the amplitude values ​​of all waveforms.

[0085] Additionally, the vector length in the rotating dq coordinate system can be used as the feature value regarding the anomaly of the electric motor EM instead of the amplitudes of the instantaneous active power P and instantaneous reactive power Q, and the presence or absence of an anomaly, or that there is an indication of an anomaly of the electric motor EM, can be diagnosed by the same procedure.

[0086] Additionally, the diagnostic unit 753 can use the frequency distribution of the amplitude of each of several waveforms contained in the time-series data of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM over a specified duration, obtained by the waveform counting method (see, for example, the section on amplitude analysis in Japanese Disclosure Patent, Publication 2023-177596). For example, the diagnostic unit 753 can diagnose that an anomaly of the electric motor EM is present, or that there is an indication of an anomaly, if the frequency distribution of the amplitudes of both the instantaneous active power P and the instantaneous reactive power Q includes an amplitude equal to or greater than a predetermined threshold, or an amplitude greater than a predetermined threshold at or greater than a predetermined frequency.Additionally, the diagnostic unit 753 can diagnose that an anomaly of the electric motor EM exists or that there is an indication of an anomaly if the frequency distribution of at least one of the amplitudes of the instantaneous active power P and instantaneous reactive power Q includes an amplitude equal to or greater than a predetermined threshold or an amplitude greater than a predetermined threshold at a predetermined frequency.

[0087] For example, the degree of an anomaly indicating an anomaly of the electric motor EM, as displayed in the current or voltage characteristic of the electric motor EM, can change according to various conditions during operation of the electric motor EM. These conditions include the control procedure conditions of the electric motor EM applied by the control circuit 70, the control gain conditions used when the control circuit 70 controls the electric motor EM, and the operating conditions of the electric motor EM. Therefore, if, for example, the diagnostic device 75 uses only the current or voltage characteristic of the electric motor EM, it might not be able to correctly diagnose that an anomaly of the electric motor EM is present, or that there is a sign of an anomaly, if the degree of anomaly indicating the anomaly of the electric motor EM, as displayed in the characteristic, is relatively small.Conversely, if the sensitivity of the diagnosis is increased, so that, for example, a relatively small anomaly appearing in the feature can be detected, a misdiagnosis may be possible, namely that an anomaly of the electric motor EM is present or that there is a sign of an anomaly when there is no anomaly of the electric motor EM or its signs.

[0088] In this example, the diagnostic device 75 can diagnose an anomaly in the electric motor EM using the instantaneous active power P and instantaneous reactive power Q, which are obtained by multiplying the current and voltage of the electric motor EM. Therefore, the diagnostic device 75 can correctly diagnose the anomaly in the electric motor EM. The reason for this is that an anomaly in the electric motor EM often appears predominantly in either the current or the voltage of the electric motor EM, and a relatively large anomaly in instantaneous active power or instantaneous reactive power can occur, which is obtained by multiplying the current and voltage, regardless of various conditions.

[0089] The notification unit 754 notifies the user of the diagnostic result from the diagnostic unit 753.

[0090] For example, the notification unit 754 displays information regarding the diagnostic result on the display unit 80. Furthermore, the notification unit 754 can transmit a signal containing information regarding the diagnostic result to the management device 200 or the terminal device 300 via the communication unit 90. Thus, the notification unit 754 can notify the user of the diagnostic result via the management device 200 or the terminal device 300.

[0091] The information regarding the diagnostic result can be transmitted from the power converter 100 (communication unit 90) to the terminal device 300 via the management device 200. [DIAGNOSTIC PROCEDURE FOR A SHORT CIRCUIT BETWEEN LAYERS OF THE ELECTRIC MOTOR]

[0092] Subsequently, a specific example of a diagnostic procedure for a specific type of anomaly of the electric motor EM is described. This example describes a specific diagnostic procedure for a short circuit between layers of the electric motor EM.

[0093] In an electric motor, a short circuit between layers (insulation deterioration) in an armature winding can occur due to discharge from gaps or damaged parts of insulating elements (e.g., coils, insulating paper, or winding insulation coatings) caused by mechanical stress or thermal degradation. When a short circuit occurs between layers in the armature winding, a reversed phase current is generated in the armature current. Consequently, an imbalance in the amplitudes of the U-phase, V-phase, and W-phase can occur.

[0094] For example, the case is considered where only the U-phase current changes α times (α ≠ 1) of the U, V, and W-phase currents due to a short circuit between layers in the electric motor EM. In this case, the U-phase current value I u , the V-phase current value I v and the W-phase current value I w by the following equations (2) to (4) using a normal amplitude I m of the electric motor EM. [Math 2] Iu=α⋅Im cos θ Iv=Imcos(θ−2π3) Iw=Imcos(θ+2π3)

[0095] For equations (2) to (4), the current value I α on the α-axis and the current value I β on the β-axis expressed by the following equations (5) and (6), by performing the three-phase / two-phase transformation from the three phases of the U-phase, V-phase and W-phase to the two phases of the fixed αβ coordinate system. [Math 3] Iα=23{α⋅Im cos θ−12⋅Im cos(θ−2π3)−12⋅Im cos(θ+2π3)}=23(α+12)⋅Im cos θ Iβ=23{32⋅Im cos(θ−2π3)−32⋅Im cos(θ+2π3)}=Im sin θ=Im sin θ

[0096] By performing the rotary coordinate transformation for equations (5) and (6), the d-axis current value I is obtained. d and the q-axis current value I q expressed by the following equations (7) and (8). [Math 4] Id=23(α+12)⋅Im cos2 θ+Im sin2 θ=23{(α2+1)⋅Im+(α2−12)⋅Im cos 2θ} Iq=23(α+12)⋅Im cos θ sin θ+Im sin θ cos θ=−23(α2−12)⋅Im sin 2θ

[0097] Thus, equations (7) and (8) show that when the phase current amplitude imbalance occurs, the d-axis and q-axis current values ​​I d , I qexhibit a component of cos2θ and a component of sin2θ, that is, a component corresponding to twice the electric angle θ. Therefore, by using a component corresponding to twice a component of the electric angle θ in the instantaneous active power P and the instantaneous reactive power Q, the diagnostic device 75 can diagnose the short circuit between layers of the electric motor EM.

[0098] In particular, the specific frequency component extraction unit 751 extracts a frequency corresponding to twice the electric angle θ (i.e., 2θ) as a specific frequency, specifically a component that has twice the rotational frequency ω (2ω). Then, the feature acquisition unit 752 extracts a feature for a component with twice the rotational frequency ω. Thus, the diagnostic unit 753 can diagnose a short circuit between layers of the electric motor EM. [SPECIFIC EXAMPLE OF A DIFFERENCE IN THE DEGREE OF ANOMALIES APPEARING IN CURRENT AND VOLTAGE]

[0099] Subsequently, with reference to Fig. 4, Fig. 5, Fig. 6 to Fig. Seven specific examples of differences in the degree of anomalies appearing in the current and voltage of electric motor EM are described, depending on various conditions of the electric motor EM. In particular, specific examples of differences in the degree of anomalies caused by a short circuit between layers of the electric motor EM are described, which appears in an amplitude value corresponding to twice the component of the electric angle θ of the current and voltage of the electric motor EM.

[0100] Fig. 4 and Fig. Figure 5 shows a first example of a simulation result of an operating state of an electric motor EM when an anomaly occurs. Fig. 6 and Fig. Figure 7 shows a second example of a simulation result of an operating state of the electric motor EM when an anomaly occurs. In particular, they show Fig. 4 and Fig. 5. The results of the simulation of the operating state of the electric motor EM when a short circuit occurs between layers of the electric motor EM, when the PI control gain (especially proportional gain) in vector control is relatively low. In contrast, they show Fig. 6 and Fig. 7 the results of the simulation of the operating state of the electric motor EM when a short circuit occurs between layers of the electric motor EM when the PI control gain (especially proportional gain) in the vector control is relatively large.

[0101] Fig. Section 4 contains sections 4A to 4D. Section 4A shows time variations of the respective phase currents of the U-phase, V-phase, and W-phase. Section 4A contains a time waveform 401 of the U-phase current value I. u (recorded value), a time waveform 402 of the V-phase current value I v (recorded value) and a time waveform 403 of the W phase current value I w (recorded value). Section 4B shows time variations of the d-axis and q-axis current values ​​I d , I q (recorded values). Section 4B contains a time waveform 411 of the d-axis current value I. d and a time waveform 412 of the q-axis current value I q Section 4C shows time variations of the d-axis and q-axis voltage values ​​V. d , V q (Command values). Section 4C contains a time waveform 421 of the d-axis voltage value V. d and a time waveform 422 of the q-axis voltage value V qSection 4D shows time variations of instantaneous active power P and instantaneous reactive power Q. Section 4D contains a time waveform 431 of instantaneous active power P and a time waveform 432 of instantaneous reactive power Q.

[0102] Fig. Figure 5 is a bar chart showing the average amplitude of the d-axis current value I. d and the q-axis current value I q , each corresponding to twice a component of an electric angle θ, average amplitude of the d-axis voltage value V d and the q-axis voltage value V q , which each correspond to twice a component of an electric angle θ, and illustrates an average value of the instantaneous active power P and instantaneous reactive power Q, which each correspond to twice a component of an electric angle θ.

[0103] Fig. Section 6 contains sections 6A to 6D. Section 6A shows time variations of the respective phase currents of the U-phase, V-phase, and W-phase. Section 6A contains a time waveform 601 of the U-phase current value I. u (recorded value), a time waveform 602 of the V-phase current value I v (recorded value) and a time waveform 603 of the W phase current value I w (recorded value). Section 6B shows time variations of the d- and q-axis current values ​​I d , I q (recorded value). Section 6B contains a time waveform 611 of the d-axis current value I. d and a time waveform 612 of the q-axis current value I q Section 6C shows time variations of the d-axis and q-axis voltage values ​​V. d , V q (Command value). Section 6C contains a time waveform 621 of the d-axis voltage value V. d and a time waveform 622 of the q-axis voltage value V qSection 6D shows time variations of instantaneous active power P and instantaneous reactive power Q. Section 6D contains a time waveform 631 of instantaneous active power P and a time waveform 632 of instantaneous reactive power Q.

[0104] Fig. Figure 7 is a bar chart showing the average amplitude of the d-axis current value I. d and the q-axis current value I q , each corresponding to twice a component of an electric angle θ, average amplitude of the d-axis voltage value V d and the q-axis voltage value V q , which each correspond to twice a component of an electric angle θ, and illustrates an average value of the instantaneous active power P and instantaneous reactive power Q, which each correspond to twice a component of an electric angle θ.

[0105] As shown in Section 4A, when the control gain is relatively low, the degree of imbalance in the phase current amplitude caused by the short circuit between layers of the electric motor EM is relatively large. Consequently, as shown in Section 4B and Fig. Figure 5 shows the amplitudes corresponding to twice a component of an electric angle θ of the d-axis current value I. d and the q-axis current value I q correspond, relatively large. As in section 4C and Fig. Figure 5 shows that when the control gain is relatively low, the amplitudes are those corresponding to twice a component of an electric angle θ at the d-axis voltage value V. d and the q-axis voltage value V qThese values ​​correspond to relatively small values. Therefore, when the control gain is relatively small, the feature of a short circuit between layers (i.e., the change associated with the occurrence of a short circuit between layers) appears relatively larger in the features corresponding to twice a component of an electric angle θ at the d-axis current value I. d and the q-axis current value I q correspond to the characteristics that correspond to twice a component of an electric angle θ at the d-axis voltage value V d and the q-axis voltage value V q are equivalent to.

[0106] In contrast, as in Fig. As shown in Figure 6A, when the control gain is relatively large, the degree of imbalance in the phase current amplitude caused by the short circuit between layers of the electric motor EM is relatively small. Consequently, as shown in Section 6B and Fig. Figure 7 shows the amplitudes corresponding to twice a component of an electric angle θ of the d-axis current value I. d and the q-axis current value I q correspond, relatively small. As in section 6C and Fig. Figure 7 shows that when the control gain is relatively large, the amplitudes are those corresponding to twice a component of an electric angle θ at the d-axis voltage value V. d and the q-axis voltage value V q corresponding to relatively large values. Therefore, if the control gain is relatively large, the layer short-circuit feature (i.e., the change associated with the occurrence of a layer short circuit) appears in the features corresponding to twice a component of an electric angle θ at the d-axis voltage value V. d and the q-axis voltage value V qcorrespond to relatively larger characteristics than those corresponding to twice a component of an electric angle θ at the d-axis current value I d and the q-axis current value I q are equivalent to.

[0107] As described above, the degree of the short-circuit characteristic varies between layers, which is reflected in the characteristics with respect to the d-axis current value I. d and the q-axis current value I q and the characteristics relating to the d-axis voltage value V d and the q-axis voltage value V q appears, depending on the setting of the control gain parameter. Therefore, if only one of the characteristics relating to the d-axis current value I d and the q-axis current value I q and the characteristics relating to the d-axis voltage value V d and the q-axis voltage value V qWhen used, it might be impossible to properly diagnose the short circuit between layers of the electric motor EM.

[0108] In contrast, as described in section 4D, Fig. 5, Section 6D and Fig. As shown in Figure 7, the amplitudes of the instantaneous active power P and the instantaneous reactive power Q are relatively large, regardless of the control gain. This is because the characteristics of the changes in the features with respect to the d-axis current value Id and the q-axis current value I are q and the characteristics relating to the d-axis voltage value V d and the q-axis voltage value V q, depending on the setting of the control gain, are opposite to each other. By using the characteristics relating to twice the component of the electrical angle θ in the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM, the diagnostic device 75 can therefore correctly diagnose the short circuit between layers of the electric motor EM, regardless of the control gain.

[0109] However, depending on the control gain, the degree of the short-circuit characteristics between the layers of the electric motor EM, which appear in the characteristics relating to twice the component of the electric angle θ in the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM (in this example, the amplitude), can change. Therefore, the diagnostic unit 753 sets the diagnostic criteria (e.g., the thresholds described above) relating to the characteristics relating to twice the component of the electric angle θ in the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM according to the setting of the control gain of the current matching unit 704. Thus, the diagnostic device 75 can more appropriately diagnose the short circuit between the layers of the electric motor EM. [PROCESSING TO DIAGNOSE AN ELECTRIC MOTOR ANOMALITY]

[0110] Subsequently, with reference to Fig. 8, Processing to diagnose an anomaly of the electric motor EM is described, which is carried out by the diagnostic device 75.

[0111] Fig. Figure 8 is a flowchart that schematically illustrates an example of a process for diagnosing an anomaly of the electric motor EM by the diagnostic device 75.

[0112] This flowchart is executed repeatedly, for example during the operation of the power converter 100 (duration from switching on the power to switching off the power) at each fixed period Ts.

[0113] This flowchart uses an integration timer (time t) and the anomaly status. Time t and the anomaly status are initialized to a state of zero (0) and a clear state, respectively, when the power converter 100 is switched on.

[0114] As in Fig.As shown in Figure 8, in one step S102 calculates the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM using the arithmetic unit 750.

[0115] When the processing of step S102 is complete, the diagnostic device 75 continues with step S104.

[0116] In step S104, the specific frequency component extraction unit 751 extracts components of a specific frequency from measurement data of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM, which are output in step S102, over a specified period of time.

[0117] When the processing of step S104 is complete, the diagnostic device 75 continues with step S106.

[0118] In step S106, the feature acquisition unit 752 obtains an amplitude value A as a feature relating to the anomaly of the electric motor EM based on the components of the instantaneous active power P and the instantaneous reactive power Q of the electric motor EM, which were obtained in step S104.

[0119] When the processing of step S106 is complete, the diagnostic device 75 continues with step S108.

[0120] In step S108, the diagnostic unit 753 determines whether the rotational frequency ω of the electric motor EM is greater than a predetermined threshold value ω. th (> 0). The threshold ω th is predetermined as the minimum value of the rotational frequency ω of the electric motor EM that is capable of diagnosing the anomaly of the electric motor EM. If the rotational frequency ω of the electric motor EM is greater than the threshold value ω thIf the diagnostic unit 753 is null, it proceeds to step S110; otherwise, it proceeds to step S118.

[0121] In step S110, the diagnostic unit 753 determines whether the average value (average amplitude value A) m ) of the amplitude value A, which corresponds to twice a component of the electric angle θ of the instantaneous active power P and the instantaneous reactive power Q, obtained in step S106, greater than the predetermined threshold A th (> 0) is.

[0122] The threshold A th corresponds to the minimum value of the average amplitude value A m , if the electric motor EM is anomalous. The threshold value A th This is predetermined, for example, by an experiment simulating an anomaly of the electric motor EM, or by a computer simulation. Furthermore, as described above, the threshold A can be thThe various conditions of the electric motor EM (e.g., control gain) must be adjusted accordingly.

[0123] If the average amplitude value A m greater than the threshold A th If the diagnostic unit 753 is correct, it proceeds to step S112; otherwise, it proceeds to step S118.

[0124] In step S112, the diagnostic unit 753 accumulates time t. For example, the diagnostic unit 753 accumulates the period of the flowchart for time t (t = t + Ts). Alternatively, the diagnostic unit 753 can accumulate time t by incrementing time t as a count value by one (t = t + 1).

[0125] When the processing of step S112 is complete, the diagnostic device 75 continues with step S114.

[0126] In step S114, the diagnostic unit 753 determines whether time t is greater than a predetermined threshold t. th(> 0). If the time t is greater than the threshold t th If the diagnostic unit 753 is null, it proceeds to step S116; otherwise, it proceeds to step S118.

[0127] The threshold t th is predetermined as the minimum time for which it can be determined that the state in which the average amplitude value A m greater than the threshold A th is not temporary, but is continuously maintained.

[0128] When the processing of step S114 is complete, the diagnostic device 75 proceeds to step S116.

[0129] In step S116, diagnostic unit 753 diagnoses an anomaly in electric motor EM and sets the anomaly status. That is, in this example, diagnostic unit 753 diagnoses an anomaly in electric motor EM when the rotational frequency ω is greater than the threshold ω. th is and the average amplitude value A m greater than the threshold A th is, continuously exceeding the threshold t th exceeds.

[0130] The notification unit 754 refers to the anomaly status data at regular intervals. Therefore, if the diagnostic unit 753 diagnoses that the electric motor EM is anomalous, the anomaly of the electric motor EM can be reported to the user by the display unit 80 or the like.

[0131] When the processing of step S116 is complete, the diagnostic device 75 terminates the processing of this flowchart.

[0132] Additionally, in step S118, the diagnostic unit 753 resets the time t to zero (0).

[0133] When the processing of step S118 is complete, the diagnostic device 75 continues with step S120.

[0134] In step S120, the diagnostic unit 753 diagnoses that the electric motor EM is functioning normally and clears the anomaly status. With the anomaly status cleared, the notification unit 754 can determine that the electric motor EM is functioning normally. Once the anomaly status has been cleared from its set state, the notification unit 754 can determine that the electric motor EM anomaly has been resolved and stop notifying the user about the anomaly.

[0135] When the processing of step S120 is complete, the diagnostic device 75 terminates the processing of the present flowchart.

[0136] As described above, if the average amplitude value A m of the specific frequency components of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM, which is extracted by the specific frequency component extraction unit 751, greater than the threshold A th The diagnostic device 75 diagnoses that the electric motor EM exhibits an anomaly. Thus, the diagnostic device 75 can detect an anomalous condition in which the average amplitude value A m the instantaneous active power P and instantaneous reactive power Q of the electric motor EM are greater than the normal state, and diagnose that the electric motor EM has an anomaly.

[0137] Furthermore, the diagnostic device 75 diagnoses that the electric motor EM has an anomaly when the condition in which the average amplitude value A m the specific frequency components of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM are greater than the threshold value A th is, to the extent that time t exceeds the threshold t th exceeds. Therefore, the diagnostic device 75 can diagnose whether the electric motor EM has an anomaly, for example by detecting a condition in which the average amplitude value A exceeds the specified value. m temporarily greater than threshold A th The anomalous condition of the electric motor EM is excluded, regardless of the anomaly of the electric motor EM. Therefore, the diagnostic device 75 can reduce misdiagnosis and improve the accuracy of the diagnosis as to whether the electric motor EM has an anomaly. [OTHER VERSIONS]

[0138] Other embodiments are then described.

[0139] The embodiment described above may be modified or changed as appropriate. Hereafter, examples in which modifications are applied to the embodiment described above are generally referred to as "modified examples".

[0140] For example, in the embodiment described above, the functions of the diagnostic device 75 can be distributed by several diagnostic devices mounted on the power converter 100.

[0141] Furthermore, in the embodiment described above, the functions of the diagnostic device 75 can be integrated into the control circuit 70.

[0142] In the embodiments and modifications described above, a function of the arithmetic unit 750 can be transferred to the outside of the diagnostic device 75. For example, the function of the arithmetic unit 750 is transferred to the control circuit 70. Additionally, for example, if the functions of the diagnostic device 75 are transferred to the outside of the power converter 100, the function of the arithmetic unit 750 is transferred to an information processing device (e.g., a microcomputer) that is integrated into the power converter 100 and is separate from the control circuit 70.

[0143] In addition to the function of the arithmetic unit 750, a function of the specific frequency component extraction unit 751 can be transferred to the 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, if the functions of the diagnostic device 75 are transferred to the outside of the power converter 100, the function of the specific frequency component extraction unit 751 is transferred to an information processing device (e.g., a microcomputer) that is integrated into the power converter 100 and is separate from the control circuit 70.

[0144] In addition to the functions of the arithmetic unit 750 and the specific frequency component extraction unit 751, a function of the feature acquisition unit 752 can be transferred to the outside of the diagnostic device 75. For example, the function of the feature acquisition unit 752 is transferred to the control circuit 70. Similarly, when the functions of the diagnostic device 75 are transferred to the outside of the power converter 100, the function of the feature acquisition unit 752 is transferred, for example, to an information processing device (e.g., a microcomputer) integrated into the power converter 100 and separate from the control circuit 70.

[0145] Furthermore, in the embodiment and the modified example described above, the diagnostic device 75 can diagnose a type of anomaly that differs from the short circuit between layers of the electric motor EM by using N-fold (N: an integer of three or more) and not twice the component of the electrical angle of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM.

[0146] Furthermore, in the embodiment described above and in the modified example, the diagnostic device 75 can use only one of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM as the feature relating to the anomaly of the electric motor EM. In this case, the arithmetic unit 750 calculates and outputs only one of the instantaneous active power P and instantaneous reactive power Q of the electric motor EM.

[0147] In the embodiment described above and in the modified example, the Arithmetic Unit 750 calculates the instantaneous active power P and the instantaneous reactive power Q based on the sensed current value and the command voltage value of the electric motor EM. However, the command current value can be used instead of the sensed current value, or the sensed voltage value can be used instead of the command voltage value. In other words, the Arithmetic Unit 750 can calculate the instantaneous active power P and the instantaneous reactive power Q based on the sensed current value, the sensed voltage value of the electric motor EM, the command value of both, or a combination of one sensed value and the other command value. [OPERATION]

[0148] The operation of the diagnostic device, the power converter and the diagnostic procedure according to the present embodiment are then described.

[0149] In a first instance of the present embodiment, a diagnostic device is provided to diagnose an anomaly of an electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor. The electric motor is, for example, the electric motor EM described above.

[0150] In the first instance of the present embodiment, a power converter can comprise a main circuit and a diagnostic unit. The power converter is, for example, the power converter 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. In particular, the main circuit unit can convert power supplied from an external source into a predetermined power output for driving the electric motor. The diagnostic unit can diagnose anomalies in the electric motor based on the measured data of at least one of the instantaneous active power and instantaneous reactive power of the electric motor.

[0151] Furthermore, in the first case of the present embodiment, a diagnostic procedure can be provided which is carried out by the diagnostic device. In particular, in the diagnostic procedure according to the present embodiment, the diagnostic device can diagnose the anomaly of the electric motor based on the measurement data of at least one of the instantaneous active power and instantaneous reactive power of the electric motor.

[0152] For example, if the motor's anomaly is diagnosed using only one of the motor's electrical current and voltage readings, the degree of the anomaly appearing in the electrical current or voltage, and thus representing the motor's anomaly, can vary depending on different conditions. Therefore, the motor's anomaly cannot be correctly diagnosed.

[0153] In contrast, in the present case, the diagnostic device and diagnostic unit (hereinafter referred to as "diagnostic device and the like") can diagnose the motor anomaly using the instantaneous active and reactive power of the motor. Therefore, the diagnostic device can correctly diagnose the motor anomaly. This is because an anomaly in the electric motor EM often appears predominantly in either the current or the voltage of the electric motor EM, and a relatively large anomaly in instantaneous active or reactive power can occur, obtained by multiplying the current and voltage, regardless of various conditions.

[0154] In a second case of the present embodiment, based on the first case, the diagnostic device and the like can diagnose the anomaly of the electric motor based on a specific frequency component of at least one of the instantaneous active power and instantaneous reactive power of the electric motor.

[0155] Thus, the diagnostic device and the like can diagnose the motor anomaly using the component of a specific frequency in which the anomaly representing the motor anomaly occurs in the current or voltage of the instantaneous active power and instantaneous reactive power of the motor according to the type of anomaly to be diagnosed.

[0156] In a third case of the present embodiment, given the second case, the specific frequency component can be a component corresponding to an integer multiple of an electric angle.

[0157] Thus, the diagnostic device or the like can diagnose a type of anomaly in which a component corresponding to the integer multiple of the electrical angle in the electric current or voltage of the electric motor may cause an anomaly.

[0158] In a fourth case of the present embodiment, given the third case, the specific frequency component can be twice the frequency of the electric angle. The anomaly of the electric motor can be a short circuit between layers of the electric motor.

[0159] Thus, the diagnostic device or the like can diagnose some kind of anomaly in the electric motor that may cause an anomaly in a component that is twice the electrical angle.

[0160] In a fifth instance of the present embodiment, based on the conditions of the second to fourth instances, the electric motor operates according to a predetermined control by a control device. The predetermined control is, for example, the vector control described above. The specific frequency component of the electric motor's current can be reduced by the predetermined control.

[0161] Even if, for example, the specific frequency component of the electric current of the electric motor is reduced by the predetermined control of the electric motor, the diagnostic device, etc., can therefore adequately diagnose the anomaly of the electric motor using the instantaneous active power or the instantaneous reactive power of the electric motor. Furthermore, even if the degree of reduction of the specific frequency component of the electric current varies due to the control gain of the predetermined control, the diagnostic device, etc., can adequately diagnose the anomaly of the electric motor using the instantaneous active power or the instantaneous reactive power of the electric motor.

[0162] Furthermore, in a sixth instance of the present embodiment, provided one of the first five instances is met, the diagnostic device and the like can operate according to a predetermined control by a control device. In this case, a diagnostic criterion can be modified according to a control gain in the predetermined control by the diagnostic device and the like. The diagnostic criterion is, for example, the threshold value described above.

[0163] Thus, the diagnostic device and the like can adequately diagnose the anomaly regarding the anomaly of the electric motor according to the degree of a reduction of the component of the specific frequency of the current, which changes according to the control gain, for example.

[0164] In a seventh case of the present embodiment, subject to the conditions of the first to sixth cases, the measurement data of at least one of the instantaneous active power and the instantaneous reactive power can be obtained in measurement data of a current and a voltage of the electric motor based on components of a d-axis and a q-axis on rotating coordinates or components of an α-axis and a β-axis on fixed coordinates.

[0165] Thus, the diagnostic device or similar can obtain measurement data of the instantaneous active power and the instantaneous reactive power.

[0166] In an eighth case of the present embodiment, subject to the conditions of the first to seventh cases, the measurement data of at least one of the instantaneous active power and the instantaneous reactive power can be obtained based on a combination of detected values ​​and control command values ​​of a current and a voltage of the electric motor.

[0167] Thus, the diagnostic device or similar can obtain measurement data of the instantaneous active power and the instantaneous reactive power.

[0168] Furthermore, the present invention is not limited to these embodiments, but various variations and modifications can be made without deviating from the scope of the present invention.

[0169] The present application is based on Japanese patent application No. 2024-112896 and claims its priority, which was filed with the Japanese Patent Office on July 12, 2024, and the entire contents of which are hereby incorporated by reference. [LIST OF REFERENCE MARKS] 1 Diagnostic system 10 Rectifier circuit 20 smoothing circuit 21 Smoothing capacitor 30 Inverter circuit 40 Current sensor 50 voltage sensor 60 Gate Driver Circuit 70 Control circuit 75 Diagnostic device 80 display unit 90 Communication unit 100 power converters 100MC main circuit 150 Rotation status sensor 200 Management device 300 terminal devices 701 Speed ​​Adjustment Unit 702 Current sensing unit 703 Vector conversion unit 704 Current matching unit 705 Vector Inverse Conversion Unit 706 Voltage compensation unit 707 Gate signal output unit 750 arithmetic units 751 Specific Frequency Component Extraction Unit 752 Feature Acquisition Unit 753 Diagnostic unit (diagnostic device) 754 notification unit A amplitude value 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 QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2022-140897

[0003] JP 2024-83207 [0078, 0081] JP 2024-112896

[0169]

Claims

[1] Diagnostic device which is designed to diagnose an anomaly of an electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor. [2] Diagnostic device according to claim 1, which is configured to diagnose the anomaly of the electric motor based on a specific frequency component of at least one of the instantaneous active power and instantaneous reactive power of the electric motor. [3] Diagnostic device according to claim 2, wherein the specific frequency component is a component corresponding to an integer multiple of an electrical angle. [4] Diagnostic device according to claim 2 or 3, wherein: the specific frequency component is twice the frequency of the electric angle; and The anomaly of the electric motor is a short circuit between layers of the electric motor. [5] Diagnostic device according to any one of claims 2 to 4, wherein: the electric motor operates according to a predetermined control by a control device; and The specific frequency component of the electric motor's current is reduced by the predetermined control. [6] Diagnostic device according to any one of claims 1 to 5, wherein: the electric motor operates according to a predetermined control by a control device; and a diagnostic criterion is changed according to a control amplification in the predetermined control. [7] Diagnostic device according to one of claims 1 to 6, wherein the measurement data of at least one of the instantaneous active power and instantaneous reactive power are obtained based on components of a d-axis and a q-axis on rotating coordinates or components of an α-axis and a β-axis on fixed coordinates in measurement data of a current and a voltage of the electric motor. [8] Diagnostic device according to one of claims 1 to 6, wherein the measurement data of at least one of the instantaneous active power and instantaneous reactive power are obtained based on a combination of detected values ​​and control command values ​​of a current and a voltage of the electric motor. [9] Power converters, comprehensive: a main circuit unit configured to convert power supplied from an external source into a predetermined power output for use in driving an electric motor; and a diagnostic unit or a diagnostic device, in particular a diagnostic device according to one of the preceding claims, which is configured to diagnose an anomaly of the electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor. [10] Diagnostic method comprising diagnosing, by means of a diagnostic unit or by means of a diagnostic device, in particular by means of a diagnostic device according to any one of claims 1 to 8, an anomaly of an electric motor based on measurement data of at least one instantaneous active power and instantaneous reactive power of the electric motor.

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