DRIVE DEVICE AND DECREASE DETERMINATION PROCEDURE

Abstract

A drive device (1) comprises a power circuit (11) and a deterioration detection device (16). The power circuit (11) outputs a current to a load, which includes a current component with a frequency determined by a natural frequency of at least one element of the load or of an oscillating element that oscillates when receiving an oscillation resulting from an electromagnetic excitation force generated in the load, or by a value of a natural multiple of a rotation frequency of a rotatable rotator, which is one of the at least one element.The deterioration detection device (16) generates frequency domain data based on a sensor signal output by a vibration sensor (93) and determines deterioration of at least one element of the load or the vibrating element based on a value of a frequency spectrum specified by the frequency domain data at the natural frequency or the rotational frequency used to determine the frequency of the current component.

Description

Technical area

[0001] The present disclosure relates to a drive device and a deterioration determination method. General state of the art

[0002] Some loads receiving power from a power source oscillate due to electromagnetic excitation. An example of such a load is an electric motor mounted on a railway vehicle to generate driving power for the railway vehicle. If any element of the electric motor deteriorates, the electric motor oscillates more severely due to electromagnetic excitation and may affect the running of the railway vehicle. To ensure reliable operation of the railway vehicle, any deterioration of the electric motor is determined. Patent Literature 1 describes an exemplary method for determining deterioration of an electric motor. The method described in Patent Literature 1 performs frequency analysis of the measured value of the ground leakage current of the electric motor to determine the condition of the electric motor as normal or abnormal based on frequency domain data. Citation listPatent literature

[0003] Patent Literature 1: Unexamined Japanese Patent Application Publication No. 2020-008347 Brief description of the inventionTechnical problem

[0004] Although the method described in Patent Literature 1 can determine any abnormality of the electric motor, the method cannot determine deterioration in any element of the electric motor, such as a rotor, a stator, and a shaft. Furthermore, the method described in Patent Literature 1 cannot determine deterioration of a vibrating element that vibrates upon receiving vibration resulting from an electromagnetic excitation force generated in the electric motor, such as deterioration of a bogie to which the electric motor is mounted.

[0005] Under these circumstances, it is an object of the present disclosure to provide a driving device and a deterioration determination method capable of determining any deterioration of the elements of a load or the vibrating member. Solution to the problem

[0006] To achieve the above-mentioned object, a drive device according to one aspect of the present disclosure includes a power circuit and a deterioration determination device. The power circuit outputs to a load a current including a current component having a frequency determined by a natural frequency of at least one element of the load, a natural frequency of a vibrating element that vibrates upon receiving vibration resulting from an electromagnetic excitation force generated in the load, or a value of a natural multiple of a rotation frequency of a rotary rotator that is one of the at least one element.The deterioration determining means generates frequency domain data indicating a vibration amount of the load or the vibrating member for each frequency based on a sensor signal output from a vibration sensor for measuring a vibration amount of the load or the vibrating member, and determines any deterioration of the at least one element of the load or the vibrating member based on a value of a frequency spectrum indicated by the frequency domain data at the natural frequency or the rotation frequency used to determine the frequency of the current component. Advantageous effects of the invention

[0007] The drive device according to the above aspect of the present disclosure outputs to the load the current including the current component having the frequency determined by the natural frequency of the element of the load, the natural frequency of the vibrating element, or the value of the natural multiple of the rotation frequency of the rotator that is one of the elements of the load. The drive device determines any deterioration of the element of the load or the vibrating element based on the frequency spectrum value at the natural frequency or the rotation frequency indicated by the frequency domain data indicating the vibration magnitude of the load or the vibrating element for each frequency. Brief description of the drawings Fig. 1 is a diagram of an exemplary drive device mounted on a railway vehicle according to Embodiment 1; Fig. 2 is a block diagram of the drive device according to Embodiment 1; Fig. 3 is a diagram of vibration sensors mounted at example positions in Embodiment 1; Fig. 4 is a block diagram of a control device in Embodiment 1; Fig. 5 is a block diagram of a deterioration determination device in Embodiment 1; Fig. 6 is a block diagram of the control device and the deterioration determination device in Embodiment 1, illustrating the hardware configuration; Fig. 7 is a flowchart showing an example of a switching operation control process executed by the control device in Embodiment 1; Fig. 8 is a flowchart showing an example of a deterioration determination process executed by the deterioration determination means in Embodiment 1; Fig. 9 is a diagram of vibration sensors mounted at example positions in Embodiment 2; Fig. 10 is a graph showing an example frequency of a voltage command in Embodiment 2; Fig. 11 is a block diagram of a drive device according to Embodiment 3; Fig. 12 is a block diagram of a control device in Embodiment 4; Fig. 13 is a flowchart showing an example of a switching operation control process executed by the control device in Embodiment 4; Fig. 14 is a diagram of vibration sensors mounted at other example positions in the embodiments; and Fig. 15 is a block diagram of a control device and a deterioration determination device according to a modification of the embodiments, illustrating the hardware configuration. Description of the embodiments

[0008] A drive device and a deterioration determination method according to embodiments of the present disclosure will be described in detail with reference to the drawings. Components that are identical or corresponding to each other are denoted by the same reference numerals in the drawings. Embodiment 1

[0009] In the example described below, a drive device 1 according to Embodiment 1 is a drive device mounted on a railway vehicle for determining deterioration of an electric motor that generates a driving force for the railway vehicle. Fig. 1 comprises one or more vehicles 51, bogies 41 movable on rails 101 and supporting the vehicles 51, and a pantograph 52 that detects power supplied from an electrical substation (not shown) via a power line 102.

[0010] In Fig. 1, the X-axis direction indicates the width direction of the vehicle 51. The Y-axis direction indicates the direction of travel of the rail vehicle 100. The Z-axis is perpendicular to the X and Y axes. The Z-axis direction indicates a vertical direction for the horizontally arranged rail vehicle 100.

[0011] At least one of the vehicles 51 is a railcar. Fig. 1 shows a vehicle 51, which is a railcar. Each vehicle 51 has two bogies 41. In Fig. 1, only one bogie 41 is shown. The current collector 52 is, for example, a pantograph that detects the current via an overhead line, which is the power line 102, or a current collector shoe that detects the current via a third rail, which is the power line 102.

[0012] For example, a power circuit 11, a control device 12 and a deterioration determination device 16 are housed in a housing installed under the floor of the vehicle 51, which in the Fig. 2 shown drive device 1. The drive device 1 shown in Fig. The rail vehicle 100 shown in Figure 1 further includes one or more electric motors 91 driven by power from the power circuit 11, which converts and outputs the input power of the pantograph 52. In Embodiment 1, two electric motors 91 are mounted on each of the two bogies 41 installed in each vehicle 51. In other words, each vehicle 51 has four electric motors 91. The four electric motors 91 in a single vehicle 51 are driven by power from the same power circuit 11.

[0013] In Embodiment 1, the rail vehicle 100 uses a direct current (DC) supply. In this case, the power circuit 11 converts the DC power collected by the pantograph 52 into three-phase alternating current (AC) power and supplies the electric motors 91 with three-phase AC power. In Embodiment 1, each motor 91 comprises a three-phase asynchronous motor and is driven by three-phase AC power from the power circuit 11.

[0014] Although the structure of each electric motor 91 is not shown in detail, each electric motor 91 includes a rotatably supported shaft, a rotor including a rotor core and rotor conductors arranged in slots in the outer peripheral surface of the rotor core, and a stator including a stator core and stator coils arranged in slots in the inner peripheral surface of the stator core. Each electric motor 91 further includes an insulator that insulates the rotor core from the rotor conductors, an insulator that insulates the stator core from the stator coils, and an insulator that insulates adjacent stator coils from each other.

[0015] As in Fig. 3, which shows the bogie 41 viewed from above in the vertical direction, the bogie 41 includes couplings 43 connected to the respective shafts of the electric motors 91, gearing devices 44 that transmit rotational power transmitted from the respective electric motors 91 to axles 45 through the respective couplings 43, the axles 45, and wheels 42 attached to both ends of each axle 45. When each electric motor 91 is driven by power from the power circuit 11, the shaft of each electric motor 91 rotates, and the rotational power of the shaft is transmitted to the axle 45 via the coupling 43 and the gearing device 44. When the axle 45 rotates, the wheels 42 attached to both ends of the axle 45 rotate to generate driving power for the rail vehicle 100.

[0016] Similarly, the other bogie 41, which is in Fig. 1, when each electric motor 91 is supplied with power from the power circuit 11, the shaft of each electric motor 91 rotates, and the rotational force of the shaft is transmitted to the axle 45 via the clutch 43 and the transmission device 44. When the axle 45 rotates, the wheels 42 attached to both ends of the axle 45 rotate to generate driving force for the rail vehicle 100.

[0017] As in Fig. As shown in Figure 3, each electric motor 91 is attached to the bogie 41. The bogie 41 thus receives vibrations resulting from the electromagnetic excitation force generated in each electric motor 91 when energized. Upon receiving vibrations transmitted from the individual electric motors 91, the bogie 41 vibrates. In other words, the bogie 41 is a vibrating element that vibrates upon receiving vibrations transmitted from the electric motors 91. Similarly, the couplings 43, the gear devices 44, the axles 45, and the wheels 42 are also vibrating elements that vibrate upon receiving vibrations transmitted from the electric motors 91.

[0018] As described below, the drive device 1 determines any deterioration of the elements of the electric motors 91 or the vibrating elements that vibrate upon receiving vibrations transmitted from the electric motors 91. As described above, the elements of each electric motor 91 include, for example, the shaft, the rotor, the stator, and the insulators. Fig. The drive device 1 shown in Fig. 2 comprises the power circuit 11 which converts the DC power supplied from the current collector 52 into three-phase AC power and supplies a load with the three-phase AC power, and the control device 12 which controls the power circuit 11 in response to an operation command S1.

[0019] The drive device 1 further includes the deterioration determination device 16, which determines deterioration of the elements of the electric motors 91 or the vibrating elements that vibrate upon receiving a vibration resulting from an electromagnetic excitation force generated in the electric motor 91. The electric motors 91 are each an example of a load that receives AC power from the power circuit 11. For the sake of simplicity, Fig. 2, only a single electric motor 91 is shown, but any number of electric motors 91 may receive power from the power circuit 11. In Embodiment 1, as described above, the four electric motors 91 in a single vehicle 51 receive power from the same power circuit 11.

[0020] Upon receiving power from the power circuit 11, each electric motor 91 oscillates under the electromagnetic excitation force. The oscillating elements oscillate upon receiving oscillation resulting from an electromagnetic excitation force from the electric motor 91. The frequency of the electromagnetic excitation force depends on the frequency of the output current of the power circuit 11. The elements of the electric motor 91 and the oscillating elements include elements whose natural frequency coincides with the frequency of the electromagnetic excitation force. Such elements oscillate and vibrate to a greater extent. The natural frequency that coincides with the frequency of the electromagnetic excitation force refers to the natural frequency that falls within a sufficiently narrow frequency range that includes the frequency of the electromagnetic excitation force. The sufficiently narrow frequency range is, for example,a frequency range that includes errors within 5% of the electromagnetic excitation force.

[0021] The elements of the electric motor 91 include rotatable rotators, such as the shaft and the rotor, which oscillate and vibrate to a greater extent when the rotation frequency matches the frequency of the electromagnetic excitation force or the frequency divided by the frequency of the electromagnetic excitation force. In other words, when the value of a natural multiple of the rotation frequency of the rotators matches the frequency of the electromagnetic excitation force, the rotators oscillate and vibrate to a greater extent. The value of the natural multiple of the rotation frequency that matches the frequency of the electromagnetic excitation force refers to the value of the natural multiple of the rotation frequency that falls within a sufficiently narrow frequency range that includes the frequency of the electromagnetic excitation force.

[0022] Therefore, when the power circuit 11 controlled by the controller 12 outputs a current including a current component with a frequency determined by the natural frequency of the elements of the electric motor 91 and the natural frequency of the oscillating elements, the elements of the electric motor 91 or the oscillating elements whose natural frequency coincides with the frequency of the current component included in the output of the power circuit 11 oscillate. The natural frequency that coincides with the frequency of the current component included in the output of the power circuit 11 refers to the natural frequency that falls within a sufficiently narrow frequency range that includes the frequency of the current component included in the output of the power circuit 11.

[0023] When the power circuit 11 outputs a current including a current component having a frequency determined by the value of the natural multiple of the rotation frequency of the rotatable rotators belonging to the elements of the electric motor 91, the rotators oscillate.

[0024] The elements of the electric motor 91 or the vibrating elements vibrate to a greater extent when the elements deteriorate than when the elements do not deteriorate. The power circuit 11 outputs a current including a current component whose frequency is determined by the natural frequency of the elements of the electric motor 91, the natural frequency of the vibrating elements, or the value of the natural multiple of the rotation frequency of the rotators. While the current including the above-mentioned current components is being output, the deterioration determination device 16 determines any deterioration of the elements of the electric motor 91 or the vibrating elements based on sensor signals detected by vibration sensors 92 that measure the vibration magnitude of the elements of the electric motor 91 or the vibrating elements.The sensor signals output by the vibration sensors 92 are analog data signals whose amplitude changes with the vibration quantity to be measured.

[0025] In Embodiment 1, the deterioration determination device 16 determines any deterioration of the shaft of the electric motor 91 based on a sensor signal output from a vibration sensor 92 that measures the vibration magnitude of the shaft of the electric motor 91. The structure in Embodiment 1 has as many vibration sensors 92 as electric motors 91. Specifically, each vehicle 51 includes four vibration sensors 92. For simplicity, Fig. 2 only a single vibration sensor 92. Each vibration sensor 92 comprises, for example, a non-contact sensor and is separated from the shaft of the corresponding electric motor 91, but adjacent to it, as in Fig. 3 shown.

[0026] The drive device 1 is described in detail below.

[0027] The Fig. The power circuit 11 shown in Figure 2 includes an input terminal 11a connected to the current collector 52 via a contactor or reactor (not shown), an input terminal 11b that is grounded, and output terminals 11c, 11d, and 11e connected to the electric motor 91. The power circuit 11 further includes a capacitor C1 connected to the input terminals 11a and 11b, and three pairs of two switching elements 13 connected in series. The three pairs of two switching elements 13 correspond to the U-phase, the V-phase, and the W-phase of the three-phase AC power. The two switching elements 13 corresponding to the U-phase, the two switching elements 13 corresponding to the V-phase, and the two switching elements 13 corresponding to the W-phase are connected in parallel between the input terminals 11a and 11b.

[0028] The connection point of the two switching elements 13 corresponding to the U phase is electrically connected to the output terminal 11c. The connection point of the two switching elements 13 corresponding to the V phase is electrically connected to the output terminal 11d. The connection point of the two switching elements 13 corresponding to the W phase is electrically connected to the output terminal 11e.

[0029] In Embodiment 1, each switching element 13 includes an insulated-gate bipolar transistor (IGBT) 14 and a freewheeling diode 15, the anode of which is connected to the emitter terminal of the IGBT 14 and the cathode of which is connected to the collector terminal of the IGBT 14. The controller 12 provides a switching control signal S2 to the gate terminal of the IGBT 14 included in each switching element 13. The switching control signal S2 switches each switching element 13 between on and off. Each switching element 13 performs the on-off switching operation to cause the power circuit 11 to convert DC power into three-phase AC power. Preferably, each switching element 13 is formed of a wide-bandgap semiconductor such as silicon carbide, a gallium nitride-based material, or diamond.

[0030] Capacitor C1 is charged with DC power supplied by current collector 52. Capacitor C1 reduces the harmonic components contained in the DC power supplied by current collector 52.

[0031] The control device 12 detects a measured rotational speed of the electric motor 91 per unit time from a rotational speed sensor 93, which detects the rotational speed of the electric motor 9. The rotational speed sensor 93 is attached, for example, to a non-drive end portion of the shaft of each electric motor 91, as shown in Fig. 3. The electric motor 91 includes a pulse generator (PG) that outputs a sensor signal with a value that changes with the rotation of the shaft. The speed sensor 93 detects the speed of the electric motor 91 per unit time based on the sensor signal output by the PG and outputs the detected speed. The structure in Embodiment 1 has as many speed sensors 93 as the electric motors 91. For simplicity, Fig. 2 only a single speed sensor 93.

[0032] The control device 12 detects the measured U-, V-, and W-phase currents from the current sensors CT1, CT2, and CT3, which measure the respective U-, V-, and W-phase currents output by the power circuit 11. The current sensors CT1, CT2, and CT3 each include a current transformer (CT) installed in the power circuit between the output terminals 11c, 11d, and 11e of the power circuit 11 and the electric motor 91.

[0033] The control device 12 receives the operation command S1 from a driver's cab (not shown). The operation command S1 indicates a command corresponding to an operation performed by an operator on a main control device installed in the driver's cab. More specifically, the operation command S1 is a turn-on command, a brake command, or a coast-down command. The coast-down command indicates a state in which neither the turn-on command nor the brake command is provided.

[0034] Based on the measured rotational speed of the electric motor 91, the measured U, V, and W phase currents, and the operating command S1 acquired as described above, the control device 12 generates a voltage command indicating a target value of the output voltage of the power circuit 11. The control device 12 generates a plurality of switching control signals S2 determined based on a voltage command and a carrier wave signal and transmits the plurality of switching control signals S2 to the plurality of switching elements 13. Thus, the output voltage of the power circuit 11 approaches the target value.

[0035] When the output power of the power circuit 11 is low, more specifically, when the speed of the rail vehicle 100 is in a low speed range, the controller 12 controls the power circuit 11 to output a rated current superimposed with a current component having a frequency determined by the value of the natural frequency of the elements of the electric motor 91, the value of the natural frequency of the oscillating elements, or the value of the natural multiple of the rotation frequency of the rotators belonging to the elements of the electric motor 91, and causes the elements of the electric motor 91 or the oscillating elements to oscillate.The frequency determined by the value of the natural frequency of the elements of the electric motor 91, the value of the natural frequency of the oscillating elements or the value of the natural multiple of the rotation frequency of the rotators is included in the frequency range in which the elements of the electric motor 91 or the oscillating elements oscillate.

[0036] The controller 12 prestores information about the natural frequency of the elements of the electric motor 91 or the vibrating elements as the deterioration determination target of the deterioration determination device 16. The natural frequency is determined by the mass and rigidity of the elements. Therefore, the controller 12 may prestore information about the natural frequency acquired from the design information about the elements of the electric motor 91 or the vibrating elements. When the deterioration determination target of the deterioration determination device 16 is a rotator, the controller 12 may determine the rotation frequency of the electric motor 91 based on the measured value acquired by the rotation speed sensor 93 and use the rotation frequency as the rotation frequency of the rotator.

[0037] For example, the low speed range of the rail vehicle 100 indicates a range in which the speed of the rail vehicle 100 is less than or equal to 30 km / h. When the speed of the rail vehicle 100 is in the low speed range, the output power of the power circuit 11 is lower than when the speed of the rail vehicle 100 is in a high speed range, and the impact on the operation of the electric motor 91 is minimal, even if the above-described current component is superimposed on the output current of the power circuit 11.

[0038] To suppress the likelihood that the above-described current component superimposed on the rated current will affect the operation of the electric motor 91, the control device 12 preferably controls the power circuit 11 so that the rated current is output when the speed of the rail vehicle 100 is higher than the speeds in the low-speed range. The rated current is alternating current that drives the electric motor 91 and has an amplitude within an amplitude range for driving the electric motor 91.

[0039] In Embodiment 1, the power circuit 11 outputs a current in which a current component with a frequency determined by the natural frequency of the shaft of the electric motor 91, specifically a current component with a frequency matching the natural frequency of the shaft of the electric motor 91, is superimposed on the rated current. The frequency corresponding to the natural frequency is a frequency that falls within a sufficiently narrow frequency range that can be equated with the natural frequency. The sufficiently narrow frequency range is, for example, a frequency range that includes errors within 5% of the natural frequency.

[0040] The control device 12 is described with reference to Fig. 4. The controller 12 includes a torque command determination circuit 21 that determines a torque command value τ*, which is a target torque value for the electric motor 91, based on an operation command S1 and a measured rotational speed of each electric motor 91 detected by the corresponding rotational speed sensor 93, and a position estimator 22 that estimates the position of the rotor in each electric motor 91 by integrating the measured rotational speed of the electric motor 91 and outputs an estimated position θ. The electric motors 91 are installed in the same vehicle 51 and operate in the same manner. Thus, the torque command determination circuit 21 determines the torque command value τ*, for example, from the average of the measured rotational speeds of the electric motors 91. Similarly, the position estimator 22 integrates the average of the measured rotational speeds of the electric motors 91 to estimate the position of the rotor.

[0041] The control device 12 further includes a coordinate converter 23 that converts the U-, V-, and W-phase currents detected by the current sensors CT1, CT2, and CT3 from three-phase coordinates to dq rotation coordinates based on the estimated position θ and determines and outputs the excitation current value id and the torque current value iq, and a current command determination circuit 24 that determines and outputs an excitation current value id* and a torque current command value iq* based on the torque command value τ*.

[0042] The control device 12 further includes a current control circuit 25 that determines an excitation voltage command value Vd* based on the difference between the excitation current value id and the excitation current command value id*, determines a torque voltage command value Vq* based on the difference between the torque current value iq and the torque current command value iq*, and outputs the excitation voltage command value Vd* and the torque voltage command value Vq*.

[0043] The controller 12 further includes a coordinate converter 26 that converts the excitation voltage command value Vd* and the torque voltage command value Vq* from dq rotation coordinates into three-phase coordinates based on the estimated position θ to determine a U-phase voltage command value Vu, a V-phase voltage command value Vv, and a W-phase voltage command value Vw. The U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw are the respective command values ​​of the U-, V-, and W-phase voltages output from the power circuit 11. The U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw output from the coordinate converter 26 are expressed by sine waves.More specifically, the coordinate converter 26 outputs a U-phase voltage command which is a sine wave and indicates the U-phase voltage command value Vu, a V-phase voltage command which is a sine wave and indicates the V-phase voltage command value Vv, and a W-phase voltage command which is a sine wave and indicates the W-phase voltage command value.

[0044] When the speed of the rail vehicle 100 is in the low-speed range, the coordinate converter 26 outputs the U-, V-, and W-phase voltage commands at a frequency consistent with the natural frequency of the shaft of the electric motor 91, so as to cause the output current of the power circuit 11 to include a current component at a frequency consistent with the natural frequency of the shaft of the electric motor 91, as described above. Specifically, when the measured speed of the electric motor 91 is in the speed range corresponding to the low-speed range of the rail vehicle 100, the coordinate converter 26 outputs the U-, V-, and W-phase voltage commands at a frequency consistent with the natural frequency of the shaft of the electric motor 91.

[0045] When the speed of the rail vehicle 100 is higher than the speeds in the low-speed range, the coordinate converter 26 outputs the U-, V-, and W-phase voltage commands in the form of sine waves at a frequency corresponding to the speed of the electric motor 91 to cause the power circuit 11 to output the rated current as described above. Specifically, when the measured speed of the electric motor 91 is outside the speed range corresponding to the low-speed range of the rail vehicle 100, the coordinate converter 26 outputs the U-, V-, and W-phase voltage commands at a frequency set based on the speed of the electric motor 91.

[0046] The control device 12 further includes a carrier wave generating circuit 27 that generates and outputs a carrier wave signal that is a triangular wave. When the speed of the rail vehicle 100 is in the low speed range, the carrier wave generating circuit 27 operates in an asynchronous mode in which the frequency of the triangular wave is set to a frequency that is defined independently of the speed of the electric motor 91 and is sufficiently higher than the rotational frequency of the electric motor 91. When the speed of the rail vehicle 100 is higher than the speeds in the low speed range, the carrier wave generating circuit 27 operates in a synchronous mode in which the frequency of the triangular wave is set based on the rotational speed of the electric motor 91.More specifically, in synchronous mode, the frequency of the triangular wave is set to the value of a natural multiple of the frequency of the U, V and W phase voltage commands at a frequency set based on the speed of the electric motor 91.

[0047] The controller 12 further includes a pulse width modulation (PWM) signal generating circuit 28 that compares the target values ​​specified by the respective U-, V-, and W-phase voltage commands, specifically, the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw, with the value of the carrier wave signal, which is a triangular wave, and generates a plurality of switching control signals S2, which are PWM signals.

[0048] As in Fig. As shown in Figure 5, the deterioration determination device 16 includes an analog-to-digital (AD) converter 31 that samples sensor signals output from vibration sensors 92 that measure the vibration magnitude of the elements of the electric motor 91 or the vibrating elements, e.g., the shaft of the electric motor 91, at predetermined intervals to generate digital data, and a frequency converter 32 that generates frequency-domain data by performing frequency conversion, e.g., a fast Fourier transform (FFT). The frequency-domain data indicates the vibration magnitude of the elements of the electric motor 91 or the vibrating elements for each frequency.

[0049] The deterioration determination device 16 further includes a determination device 33 that determines any deterioration of the elements of the electric motor 91 or the oscillating elements based on the frequency spectrum value indicated by the frequency domain data at the natural frequency of the elements of the electric motor 91 or the oscillating elements, or at the rotation frequency of the rotators used to determine the frequency of the current superimposed on the rated current. The determination device 33 may prestore information about the natural frequency of the elements of the electric motor 91 or the oscillating elements as a deterioration determination target. The determination device 33 may detect the measured rotational speed of the electric motor 91 per unit time from the rotational speed sensor 93 and determine the rotational frequency based on the detected measured rotational speed.

[0050] More specifically, the determining device 33 compares the frequency spectrum value at the natural frequency of an element of the electric motor 91 with the value of a threshold spectrum corresponding to the element of the electric motor 91. If the frequency spectrum value at the natural frequency of the element of the electric motor 91, which is indicated by the frequency domain data, is greater than or equal to the value of the threshold spectrum, it can be determined that the element of the electric motor 91 has deteriorated.

[0051] The determination device 33 further compares the frequency spectrum value at the natural frequency of the vibrating element with the value of the threshold spectrum corresponding to the vibrating element. If the frequency spectrum value at the natural frequency of the vibrating element, which is indicated by the frequency domain data, is greater than or equal to the threshold spectrum value, it can be determined that the vibrating element is deteriorating.

[0052] The determination device 33 further compares the frequency spectrum value at the rotation frequency of the rotator with the value of the threshold spectrum corresponding to the rotator. If the frequency spectrum value at the rotation frequency of the rotator, which is indicated by the frequency domain data, is greater than or equal to the value of the threshold spectrum, it can be determined that the rotator, which is one of the elements of the electric motor 91, is deteriorating.

[0053] As in Fig. 6, the controller 12 and the deterioration determination device 16 having the above structure are implemented by a processing circuit 71. The processing circuit 71 is connected, for example, to the vibration sensor 92, the rotational speed sensor 93, and the current sensors CT1, CT2, and CT3 via an interface circuit 72. When the processing circuit 71 is dedicated hardware, the processing circuit 71 includes, for example, a single circuit, a complex circuit, a processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination of two or more of these circuits. Each part of the controller 12 can be implemented by a single processing circuit 71 or by a common processing circuit 71.Similarly, each part of the deterioration determination means 16 may be implemented by a single processing circuit 71 or by a common processing circuit 71.

[0054] The process for controlling the switching operation of each switching element 13, which is carried out by the control device 12 having the structure described above, will be described with reference to Fig. 7. When the control device 12 detects the operating command S1 from the driver's cab, the control device 12 starts the Fig. 7. If the operation command does not indicate a power-on command (No in step S11), the processing in step S11 is repeated.

[0055] If the operation command indicates the turn-on command (Yes in step S11) and the measured speed of the electric motor 91 is higher than the threshold speed, which is the upper limit of the speed range corresponding to the low-speed range of the rail vehicle 100 (No in step S12), the controller 12 generates a voltage command with a frequency determined by the speed of the electric motor 91, specifically, U-, V-, and W-phase voltage commands (step S13). Specifically, if the measured speed of the electric motor 91 detected by the speed sensor 93 is higher than the threshold speed, the coordinate converter 26 outputs a voltage command with a frequency determined by the speed of the electric motor 91.

[0056] If the measured speed of the electric motor 91 is less than or equal to the threshold speed (Yes in step S12), the coordinate converter 26 generates a voltage command with a frequency determined by the natural frequency of the elements of the electric motor 91 or the oscillating elements, or by the rotation frequency of the rotators (step S14). For example, the coordinate converter 26 generates a voltage command with a frequency corresponding to the natural frequency of the shaft of the electric motor 91.

[0057] After the processing in steps S13 and S14, the PWM signal generation circuit 28 compares the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw, respectively specified by the U-, V-, and W-phase voltage commands, with the values ​​specified by the carrier wave signals to generate the multiple switching control signals S2, and transmits the switching control signals S2 to the multiple switching elements 13 (step S15). The above-mentioned process is then repeatedly executed from step S11.

[0058] As described above, the controller 12 controls the output voltage of the power circuit 11 to be closer to the target value specified by the voltage command generated in step S13 or step S14. Thus, the frequency of the output voltage and output current of the power circuit 11 substantially corresponds to the frequency of the voltage command generated in step S13 or step S14. In other words, when the measured rotational speed of the electric motor 91 is less than or equal to the threshold rotational speed, the frequency of the output current of the power circuit 11 is determined by the natural frequency of the elements of the electric motor 91 or the oscillating elements, or by the rotational frequency of the rotator.

[0059] The operation for determining any deterioration of the elements of the electric motor 91 or the vibrating elements, which is carried out by the deterioration determining device 16, is described below. Any deterioration of the elements of the electric motor 91 or the vibrating elements is determined via the resonance of the elements of the electric motor 91 or the vibrating elements, whose natural frequency coincides with the frequency of the current component present at the output of the power circuit 11, or via the resonance of the rotors, whose value of the natural multiple of the rotation frequency coincides with the frequency of the current component present at the output of the power circuit 11. The deterioration determining device 16 detects the multiple switching control signals S2 from the control device 12 and starts the Fig. 8 when the multiple switching control signals S2 indicate that one of the switching elements 13 is turned on.

[0060] The AD converter 31 samples the sensor signals output by the vibration sensors 92 at predetermined intervals and performs AD conversion (step S21). Specifically, the AD converter 31 converts the sensor signals output by the vibration sensors 92 at predetermined intervals and generates digital data indicating the vibration magnitude measured by each vibration sensor 92.

[0061] The frequency converter 32 performs frequency conversion of the digital data generated in step S21, specifically, data conversion from the time domain to the frequency domain to generate frequency domain data (step S22). Specifically, the frequency converter 32 converts the frequency domain data based on the measured value of each vibration sensor 92.

[0062] The determination device 33 determines any deterioration of the elements of the electric motor 91 or the vibrating elements based on the frequency spectrum value indicated by the frequency domain data generated in step S22 at the natural frequency of the elements of the electric motor 91 or the vibrating elements, or at the rotation frequency of the rotators used to determine the frequency of the current superimposed on the rated current, and based on the value of the threshold spectrum corresponding to each element of the electric motor 91 and the vibrating element (step S23). The elements of the electric motor 91 that have the defined threshold spectrum include non-rotating elements and rotators.In Embodiment 1, the determination device 33 compares the frequency spectrum value at the natural frequency of the shaft of the electric motor 91, indicated by the frequency domain data, with the value of the threshold spectrum corresponding to the shaft of the electric motor 91. If the value of the frequency spectrum at the natural frequency of the shaft of the electric motor 91, indicated by the frequency domain data, is greater than or equal to the value of the threshold spectrum, it can be determined that the shaft of the electric motor 91 has deteriorated.

[0063] The determination device 33 transmits the determination result in step S23 to the control device 12. The above-mentioned process is then repeatedly executed starting from step S21. If the control device 12 receives a determination result from the determination device 33 indicating that the elements of the electric motor 91 have deteriorated, the control device 12 turns off the power circuit 11.

[0064] As described above, when the speed of the railway vehicle 100 is in the low-speed range, the drive device 1 according to Embodiment 1 outputs from the power circuit 11 a current including a current component having a frequency determined by the natural frequency of the elements of the electric motor 91 or the vibrating elements, or by the rotation frequency of the rotary rotators belonging to the elements of the electric motor 91. The drive device 1 determines, with the deterioration determination device 16, deterioration of the elements of the electric motor 91 or the vibrating elements based on the frequency spectrum indicated by the frequency domain data based on the measured value of the vibration sensor 92. Increasing the frequency of the output current of the power circuit 11 causes a decrease in the amplitude of the vibration resulting from the electromagnetic excitation force.In this way, any deterioration of the elements of the electric motor 91 can be determined, with the probability that the electric motor 91 will be affected by vibrations being reduced.

[0065] Although the measured value of the vibration sensor 92 includes the vibration magnitude resulting from the running of the rail vehicle 100, the vibration resulting from the running of the rail vehicle 100 does not have a peak at the natural frequency of the elements of the electric motor 91 or the vibrating elements in the frequency domain. Thus, the drive device 1 can determine any deterioration based on the frequency spectrum value at the natural frequency of the elements of the electric motor 91 or the vibrating elements or at the rotation frequency of the rotators, as described above, thereby reducing the likelihood of the running rail vehicle 100 being affected by vibration. Embodiment 2

[0066] In Embodiment 1, any deterioration of the shaft of the electric motor 91 is determined, but the drive device 1 can determine any deterioration of any of the many elements of the electric motor 91. The structure of a drive device 1 according to Embodiment 2 is the same as that in Fig. 2 shown structure of the drive device 1 according to embodiment 1. In embodiment 2, as in Fig. As shown in Figure 9, the vibration sensors 94 are each mounted on the outer surface of a vertical upper portion of the corresponding electric motor 91. In this case, the measured values ​​of each vibration sensor 94 include vibration of the various elements of each electric motor 91, such as a stator, a frame to which the stator is attached, a rotor, a shaft, and a bearing that rotatably supports the shaft.

[0067] The structure of the power circuit 11 and the controller 12 is the same as in Embodiment 1, but differs from the structure in Embodiment 1 in that the controller 12 performs control to change the frequency of the current component included in the current output from the power circuit 11 for each determination period. The determination period is a period for determining any deterioration of the elements of the electric motor 91 or the vibrating elements with the deterioration determination device 16 and is, for example, 10 seconds or less.

[0068] The control device 12 changes the frequency of the current component superimposed on the rated current for each determination period. More specifically, the coordinate converter 26 in the control device 12 outputs a voltage command with a different frequency for each determination period. Fig. Figure 10 shows an example of the change in the frequency of the voltage command over time. Time T1 denotes the time at which the operating command S1, which includes the turn-on command, is provided. At time T1, the control device 12 begins controlling the switching elements 13. In a determination period P1 immediately after time T1, the coordinate converter 26 generates, for example, a voltage command with a frequency corresponding to a natural frequency f1 of the stator of the electric motor 91.

[0069] Time T2 denotes the end time of the determination period P1. In a determination period P2 immediately after time T2, the coordinate converter 26 generates, for example, a voltage command with a frequency corresponding to a natural frequency f2 of the frame of the electric motor 91.

[0070] Time T3 denotes the end time of the determination period P2. In a determination period P3 immediately after time T3, the coordinate converter 26 generates, for example, a voltage command with a frequency corresponding to a natural frequency f3 of the stator coils of the electric motor 91.

[0071] Time T4 denotes the end time of the determination period P3. At time T4, the speed of the electric motor 91 essentially reaches the threshold speed. At and after time T4, the coordinate converter 26 generates a voltage command with a frequency determined by the speed of the electric motor 91.

[0072] The deterioration determination device 16 stores information about the threshold spectrum corresponding to each of the plurality of elements of the electric motor 91 and the vibrating elements in advance. The deterioration determination device 16 compares the frequency spectrum value indicated by the frequency domain data with the threshold spectrum at the natural frequency of each of the plurality of elements of the electric motor 91 and the vibrating elements, and determines any deterioration of each of the plurality of elements of the electric motor 91 and the vibrating elements.

[0073] As described above, the drive device 1 according to Embodiment 2 can determine any deterioration of each of the plurality of elements of the electric motor 91 and the oscillating elements by changing the frequency of the current component included in the output current of the power circuit 11 for each determination period. Embodiment 3

[0074] The deterioration determination device 16 can determine any deterioration of the elements of the electric motor or the vibrating elements based on measured values ​​from vibration sensors mounted on various vehicles 51 of the rail vehicle 100. In Embodiment 3 described below, a drive device 2 also determines any deterioration of the elements of an electric motor 95 in a vehicle 51 other than the one in which the electric motor 91 is installed, and the vibrating elements that vibrate upon receiving vibration resulting from an electromagnetic excitation force generated in the electric motor 95.

[0075] As in Fig. 11, the drive device 2 according to Embodiment 3 includes, in addition to the components of the drive device 1, a power circuit 61 that converts supplied DC power into three-phase AC power and supplies the resulting AC power to a load, and a controller 62 that generates a plurality of switching control signals S3 that control a plurality of switching elements 13 included in the power circuit 61 in response to the operation command S1.

[0076] The power circuit 61 is connected to the current collector 52, e.g., via a contactor or a reactor, not shown. The power circuit 61 has a similar structure to the power circuit 11. The power circuit 61 converts the DC power supplied via the input terminals 61a and 61b into three-phase AC power and supplies the resulting AC power to the electric motor 95 via the output terminals 61c, 61d, and 61e. The electric motor 95 has a similar structure to the electric motor 91. Similar to the electric motors 91, two electric motors 95 are mounted on each of the two bogies 41 of a vehicle 51.

[0077] Current sensors CT11, CT12, and CT13 have the same structure as current sensors CT1, CT2, and CT3. Current sensors CT11, CT12, and CT13 measure the respective values ​​of the U, V, and W phase currents output by power circuit 61.

[0078] The control device 62 has a similar structure to the control device 12. The control device 62 detects an operating command S1 from the driver's cab and detects a measured speed of the electric motor 95 from a speed sensor 96, which measures the speed of the electric motor 95. The speed sensor 96 has a similar structure to the speed sensor 93. The control device 62 transmits the multiple switching control signals S3 to the multiple switching elements 13 included in the power circuit 61.

[0079] The deterioration determination means 16 determines any deterioration of the elements of the electric motor 91, the vibrating elements that vibrate upon receiving a vibration resulting from an electromagnetic excitation force generated in the electric motor 91, the elements of the electric motor 95 installed in a vehicle 51 other than the vehicle 51 in which the electric motor 91 is installed, or the vibrating elements that vibrate upon receiving a vibration resulting from an electromagnetic excitation force generated in the electric motor 95.

[0080] More specifically, while the power circuits 11 and 61 each output a current including a current component having a frequency determined by the natural frequency of the elements of the electric motors 91 and 95 or the vibrating elements, the deterioration determining means 16 determines any deterioration of the elements of the electric motors 91 and 95 or the vibrating elements based on the sensor signals detected by the vibration sensors 92 and 97 that measure the vibration amount of the elements of the electric motors 91 and 95 or the vibrating elements.

[0081] The deterioration determining means 16 further determines, while the power circuits 11 and 61 each output a current including a current component having a frequency determined by the value of a natural multiple of the rotation frequency of the rotators corresponding to the elements of the electric motors 91 and 95, any deterioration of the elements of the electric motors 91 and 95 or the vibrating elements based on the sensor signals detected by the vibration sensors 92 and 97 that measure the vibration amount of the elements of the electric motors 91 and 95 or the vibrating elements.

[0082] The vibration sensor 97 has a similar structure to the vibration sensor 92. Similar to the vibration sensors 92, each vibration sensor 97 is separate from, but adjacent to, the shaft of the corresponding electric motor 95.

[0083] The deterioration determination device 16 has a similar structure to Embodiment 1. The AD converter 31 samples the sensor signals output from the vibration sensors 92 and 97 at predetermined intervals and generates digital data indicating the vibration amount measured by each of the vibration sensors 92 and 97.

[0084] The frequency converter 32 generates frequency domain data based on the measured values ​​of each vibration sensor 92 and frequency domain data based on the measured values ​​of each vibration sensor 97.

[0085] The determining means 33 determines any deterioration of the elements of the electric motors 91 and 95 or the vibrating elements based on the change in the frequency spectrum values ​​indicated by the frequency domain data based on the measured values ​​of each vibration sensor 92 and the frequency spectrum values ​​indicated by the frequency domain data based on the measured values ​​of each vibration sensor 97.

[0086] For example, the determining device 33 calculates the variance of the value of the frequency spectrum at the natural frequency of the shaft of the electric motor 91, which is determined by the frequency-domain data based on the measured values ​​of each vibration sensor 92, and the value of the frequency spectrum at the natural frequency of the shaft of the electric motor 95, which is determined by the frequency-domain data based on the measured values ​​of each vibration sensor 97. If the calculated variance is greater than a variance threshold defined by the allowable range of deviation of the frequency spectrum values, it can be determined that the shaft of the electric motor 91 or 95 corresponding to the frequency spectrum value with the largest deviation from the average of the frequency spectrum values ​​is deteriorating.

[0087] As described above, the drive device 2 according to Embodiment 3 can determine any deterioration of the elements of the electric motors 91 and 95 or the vibrating elements in various vehicles 51. Embodiment 4

[0088] The method for the power circuit 11 to output a current component with a frequency determined by the natural frequency of the elements of the electric motor 91 or the oscillating elements, or by the rotation frequency of the rotators, is not limited to the above examples. In Embodiment 4 described below, a drive device 1 includes a power circuit 11 that, when the rail vehicle 100 is coasting or braking, outputs a current component with a frequency determined by the value of the natural frequency of the elements of the electric motor 91 or the oscillating elements, or by the value of a natural multiple of the rotation frequency of the rotators.

[0089] The components of the drive device 1 according to Embodiment 4 are the same as in Embodiment 1. The structure of the Fig. The control device 12 shown in Fig. 12 is basically the same as in Embodiment 1, but differs from the structure in Embodiment 1 in that the coordinate converter 26 detects the operation command S1.

[0090] The operation of the control device 12 is based on Fig. 13. When the control device 12 detects the operating command S1 from the driver's cab, the control device 12 starts the Fig. 13. When the operation command indicates a turn-on command (Yes in step S31), or in other words, during acceleration of the rail vehicle 100, the controller 12 generates a voltage command with a frequency determined by the rotational speed of the electric motor 91, specifically, U-, V-, and W-phase voltage commands (step S32).

[0091] When the operation indicates a coasting or braking command (No in step S31), or in other words, during coasting or braking of the rail vehicle 100, the controller 12 generates a voltage command with a frequency determined by the natural frequency of the elements of the electric motor 91 or the vibrating element, or by the rotation frequency of the rotator (step S33). Specifically, when the operation command S1 includes a coasting command or a braking command, the coordinate converter 26 generates a voltage command with a frequency determined by the natural frequency of the elements of the electric motor 91 or the vibrating elements, regardless of the torque-voltage command value Vq* and the excitation voltage command value Vd*.The voltage command generated in step S33, more specifically, the U-, V-, and W-phase voltage commands each have a smaller amplitude than an amplitude of the voltage command generated when the operation command S1 includes the turn-on command.

[0092] After the processing in steps S32 and S33, the PWM signal generation circuit 28 compares the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw specified by the U-, V-, and W-phase voltage commands with the values ​​specified by the carrier wave signals to generate the multiple switching control signals S2 and transmit the switching control signals S2 to the multiple switching elements 13 (step S34). The above processing is then repeatedly executed from step S31.

[0093] As described above, the controller 12 controls the output voltage of the power circuit 11 to be closer to the target value specified by the voltage command generated in step S32 or step S33. Thus, the frequency of the output voltage and output current of the power circuit 11 substantially corresponds to the frequency of the voltage command generated in step S32 or step S33. In other words, when the rail vehicle 100 is coasting or braking, the frequency of the output current of the power circuit 11 is determined by the natural frequency of the elements of the electric motor 91 or the oscillating elements, or by the rotation frequency of the rotors.

[0094] The structure and operation of the deterioration determination device 16 is basically the same as in Embodiment 1, but differs from the structure in Embodiment 1 in that the deterioration determination device 16 detects the operation command S1. The deterioration determination device 16 starts the Fig. 8 when the operating command S1 includes a coasting command or a braking command.

[0095] As described above, during the coasting or braking of the railway vehicle 100, the drive device 1 according to Embodiment 4 outputs from the power circuit 11 a current including a current component with a frequency determined by the natural frequency of the elements of the electric motor 91 or the vibrating elements. The drive device 1 can determine, with the deterioration determination device 16, any deterioration of the elements of the electric motor 91 or the vibrating elements based on the frequency spectrum indicated by the frequency domain data based on the measured value of the vibration sensor 92.

[0096] During coasting or braking of the rail vehicle 100, the power circuit 11 outputs a current comprising a current component with a frequency determined by the natural frequency of the elements of the electric motor 91 or the oscillating elements. The drive device 1 can thus detect any deterioration of the elements of the electric motor 91 or the oscillating elements without affecting the operation of the electric motor 91 during startup, which generates a driving force for the rail vehicle 100.

[0097] The present disclosure is not limited to the above embodiments. The above-described embodiments can be combined as appropriate. In one example, the drive device 1 according to Embodiment 4, similar to the drive device 1 according to Embodiment 2, can change the frequency of the current output from the power circuit 11 for each determination period.

[0098] The output current of the power circuit 11 is not limited to a current component with a frequency that matches the natural frequency of the elements of the electric motor 91, but may include a current component with a frequency that matches the natural frequency of the elements of the electric motor 91, the natural frequency of the oscillating elements, or the natural multiple of the rotation frequency of the rotors belonging to the elements of the electric motor 91. In one example, the output current of the power circuit 11 may include a current component with a frequency that matches a natural multiple of the rotation frequency of the rotors of the electric motor 91, e.g., a frequency corresponding to a value twice the rotation frequency of the rotors of the electric motor 91.

[0099] The drive device 1 may further comprise a power circuit independent of the power circuit 11, which outputs a current at a frequency determined by the natural frequency of the elements of the electric motor 91 or the oscillating elements. The drive device 1 may superimpose the current output by the power circuit on the output of the power circuit 11 to supply the superimposed current to the electric motor 91. In this case, the power circuit independent of the power circuit 11 preferably outputs a current with an amplitude sufficiently smaller than the amplitude of the rated current of the power circuit 11.

[0100] Similarly, the drive device 2 may further comprise a power circuit independent of the power circuits 11 and 61, which outputs a current at a frequency determined by the natural frequency of the elements of the electric motors 91 and 95 or the oscillating elements. The drive device 2 may superimpose the current output by the power circuit with the output of the power circuits 11 and 61 and supply the resulting output to the electric motor 95. In this case, the power circuit independent of the power circuits 11 and 61 preferably outputs a current with an amplitude sufficiently smaller than the amplitude of the rated current of the power circuits 11 and 61.

[0101] The drive device 1 may further comprise a plurality of power circuits independent of the power circuit 11, which output a current at a frequency determined by the natural frequency of the current components of the corresponding electric motor 91 or the oscillating elements, or by the value of a natural multiple of the rotation frequency of the rotators. The drive device 1 may superimpose the current output by each power circuit with the output of the power circuit 11 and supply the resulting output to the electric motor 91. In this case, preferably, each power circuit independent of the power circuit 11 outputs a current with an amplitude sufficiently smaller than the amplitude of the rated current of the power circuit 11. When a current comprising a plurality of current components is supplied to the electric motor 91, a plurality of elements of the electric motor 91 and the oscillating elements oscillate simultaneously.In this case, the deterioration determining means 16 can determine deterioration of the elements of the electric motor 91 and the vibrating elements from the values ​​of the frequency spectrum at the respective natural frequencies of the elements of the electric motor 91 and the vibrating elements, which are indicated by the data of the frequency range and the threshold spectrum at the respective natural frequencies of the elements of the electric motor 91 and the vibrating elements.

[0102] The structure of the control devices 12 and 62 is not limited to the above examples and may be any structure that enables generation of the switching control signals S2, which are PWM signals, to control the switching elements 13 included in the power circuits 11 and 61. In one example, the carrier wave generation circuit 27 may generate a carrier wave signal that is a sawtooth wave.

[0103] The deterioration determination device 16 may be implemented as a function of the control device 12 or as a function of a train information management system, not shown.

[0104] The frequency converter 32 is not limited to the above example, but can, for example, perform the discrete Fourier transform (DFT) to generate data in the frequency domain.

[0105] In addition to determining any deterioration described above, the deterioration determining device 16 can also determine any indication of deterioration. For example, the determining device 33 provided in the deterioration determining device 16 stores a first threshold spectrum and a second threshold spectrum that is greater than the first threshold spectrum. In this case, if, for example, the frequency spectrum at the natural frequency of the shaft of the electric motor 91, which is indicated by the frequency domain data, is greater than or equal to the first threshold spectrum and less than the second threshold spectrum, the determining device 33 determines an indication of deterioration of the shaft of the electric motor 91.For example, when the frequency spectrum at the natural frequency of the shaft of the electric motor 91 indicated by the frequency domain data is greater than or equal to the second threshold spectrum, the determining means 33 determines deterioration of the shaft of the electric motor 91.

[0106] The deterioration determination device 16 can transmit the result of the determination to a display in the driver's cab. In this case, the result of the determination is displayed on the display in the driver's cab, so that the driver can be informed of any deterioration or indication of deterioration of the elements of the electric motors 91 and 95 or the vibrating elements.

[0107] In the above embodiments, the determination device 33 stores the value of the threshold spectrum in advance, but may learn the value of the threshold spectrum through machine learning. For example, the determination device 33 learns, as a normal value, the value of the frequency spectrum indicated by the frequency domain data generated by the frequency converter 32 when the electric motor 91 is driven and neither the elements of the electric motor 91 nor the vibrating elements show deterioration. The determination device 33 learns, as an abnormal value, the value of the frequency spectrum indicated by the frequency domain data generated by the frequency converter 32 when the electric motor 91 is driven and either the elements of the electric motor 91 or the vibrating elements show deterioration.The determining device 33 can then determine a threshold spectrum whose value is greater than the normal value and smaller than the abnormal value.

[0108] A contactor may be provided between each electric motor 91 and the power circuit 11 to disconnect the electric motor 91 from the power circuit 11. A contactor controller may also be provided to turn the contactor on and off. In this case, the contactor controller turns off the contactor between the electric motor 91 with a deteriorating element and the power circuit 11 when the deterioration determination device 16 determines deterioration of the elements of the electric motor 91. This allows the power circuit 11 to continue supplying power to the electric motors 91 whose elements are not damaged.

[0109] The position where each speed sensor 93 is mounted is not limited to the above examples. The speed sensor 93 may be mounted on the transmission device 44 or on the axle 45.

[0110] In addition to the Fig. 14, a vibration sensor 98 may be mounted on the bogie 41. In addition to the vibration sensors 92 shown in Fig. 9 shown vibration sensors 94, the in Fig. 14 shown vibration sensor 98 can be provided.

[0111] Two of the current sensors CT1, CT2, and CT3 may be provided alone. For example, when only the current sensors CT1 and CT2 are provided, the controller 12 estimates the value of the W-phase current based on the measured value of the U-phase current detected by the current sensor CT1 and the measured value of the V-phase current detected by the current sensor CT2.

[0112] Electric motors 91 and 95 are not limited to three-phase asynchronous motors. In one example, electric motors 91 and 95 may be synchronous electric motors or DC electric motors. If electric motors 91 and 95 are DC electric motors, power circuits 11 and 61 may output a current detected by superimposing a current at a frequency determined by the natural frequency of the elements of electric motors 91 and 95 or the oscillating elements. In another example, electric motors 91 and 95 may be inner rotors or outer rotors.

[0113] The loads of the drive devices 1 and 2 serving as deterioration determination targets are not limited to the electric motors 91 and 95, but may be any loads supplied with power by the power circuits 11 and 61. In one example, the drive devices 1 and 2 may determine any deterioration of elements of, for example, lighting systems and air conditioning systems.

[0114] The hardware design and flowcharts described above are examples and can be changed or modified as required.

[0115] The functions of the control device 12 and the deterioration determination device 16 can be implemented by software. In an example, Fig. 15 shows a hardware configuration of the control device 12 and the deterioration determination device 16 when the functions of the control device 12 and the deterioration determination device 16 are implemented by software. The control device 12 and the deterioration determination device 16 each include a processor 81, a memory 82, and an interface 83. A bus 80 connects the processor 81, the memory 82, and the interface 83 to one another.

[0116] The functions of the control device 12 and the deterioration determination device 16 are implemented by software, firmware, or a combination of software and firmware. The software and firmware are described as programs and are stored in the memory 82. The processor 81 reads and executes the programs stored in the memory 82 to perform the functions of the aforementioned devices. In other words, the memory 82 stores programs for executing the processing of the control device 12 and the deterioration determination device 16.

[0117] The memory 82 is, for example, a non-volatile or volatile semiconductor memory such as a random access memory (RAM), a read-only memory (ROM), a flash memory, an erasable programmable read-only memory (EPROM), and an electrically erasable programmable ROM (EEPROM), a magnetic disk, a flexible disk, an optical disk, a compact disc, a minidisc, a digital versatile disc (DVD), and others.

[0118] Some of the functions of the control device 12 and the deterioration determination device 16 can be implemented by dedicated hardware, and other functions can be implemented by software or firmware. For example, in the control device 12, the torque command determination circuit 21, the current command determination circuit 24, the current control circuit 25, the carrier wave generation circuit 27, and the PWM signal generation circuit 28 can be implemented by the Fig. 6, while the position estimator 22 and the coordinate converters 23 and 26 are implemented by the processing circuit 71 shown in Fig. 15, which reads and executes the programs stored in memory 82.

[0119] The foregoing describes some exemplary embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, those skilled in the art will recognize that changes may be made in form and details without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims, along with the full range of equivalence to which such claims are entitled. List of reference symbols 1, 2 drive device 11, 61 power circuit 11a, 11b, 61a, 61b Input Terminal 11c, 11d, 11e, 61c, 61d, 61e Output terminal 12, 62 control device 13 Switching element 14 IGBT 15 Freewheeling diode 16 Deterioration determination device 21 Torque command determination circuit 22 position estimators 23, 26 Coordinate converter 24 Current command determination circuit 25 Current control circuit 27 Carrier wave generation circuit 28 PWM signal generation circuit 31 AD converters 32 frequency converters 33 Destination facility 41 bogie 42 wheels 43 Clutch 44 Gearbox 45 Axis 51 vehicles 52 pantographs 71 Processing circuit 72 Interface circuit 80 buses 81 processor 82 storage 83 Interface 91, 95 electric motor 92, 94, 97, 98 Vibration sensor 93, 96 speed sensor 100 rail vehicles 101 Rail 102 power line C1 capacitor CT1, CT2, CT3, CT11, CT12, CT13 current sensor S1 operating command S2, S3 switching control signal QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] JP 2020

[0003]

Claims

[1] Drive device, comprising: a power circuit for outputting a current to a load, the current comprising a current component having a frequency determined by a natural frequency of at least one element of the load, a natural frequency of an oscillating element that oscillates upon receiving a vibration resulting from an electromagnetic excitation force generated in the load, or a value of a natural multiple of a rotation frequency of a rotatable rotator that is one of the at least one element; and a deterioration determination device for generating frequency domain data indicative of a vibration amount of the load or the vibrating element for each frequency based on a sensor signal output from a vibration sensor for measuring a vibration amount of the load or the vibrating element, and for determining any deterioration of the at least one element of the load or the vibrating element based on a value of a frequency spectrum indicated by the frequency domain data at the natural frequency or the rotational frequency used to determine the frequency of the current component. [2] The drive device according to claim 1, wherein the power circuit outputs to the load a current comprising one or more current components, each of which has a frequency determined by the natural frequency of one of the at least one element of the load or the vibrating element or by the value of the natural multiple of the rotation frequency of the rotator, and has an amplitude smaller than the amplitude of a rated current of the power circuit. [3] Drive device according to claim 1, wherein the power circuit comprises a plurality of switching elements, converts input power into AC power, which is supplied to an electric motor included in the load to generate a driving force for a rail vehicle, and supplies the AC power resulting from the conversion to the electric motor, the drive device further comprises a control device for generating a voltage command indicating a target value of an output voltage of the power circuit, for generating a plurality of switching control signals determined by the voltage command and a carrier wave signal, and for transmitting the plurality of switching control signals to the plurality of switching elements included in the power circuit, and the control device generates the voltage command during acceleration of the rail vehicle at a frequency determined by a rotational speed of the electric motor, and during coasting or braking of the rail vehicle generates the voltage command at a frequency determined by a value of a natural frequency of at least one element of the electric motor, a value of the natural frequency of the oscillating element or the value of the natural multiple of the rotational frequency of the rotator, and with an amplitude that is smaller than an amplitude of the voltage command generated during acceleration of the rail vehicle. [4] The drive device according to claim 1, wherein the power circuit superimposes on a rated current one or more current components each having a frequency determined by a value of the natural frequency of one of the at least one element of the load or the vibrating element or by the value of the natural multiple of the rotation frequency of the rotator and having an amplitude smaller than an amplitude of the rated current, and outputs the rated current on which the one or more current components are superimposed. [5] Drive device according to claim 1, wherein the power circuit converts input power into AC power, which is supplied to an electric motor included in the load, and supplies the AC power resulting from the conversion to the electric motor, the drive device further comprises a control device for generating a voltage command indicating a target value of an output voltage of the power circuit, for generating a plurality of switching control signals determined by the target value indicated by the voltage command and a value of a carrier wave signal, and for transmitting the plurality of switching control signals to a plurality of switching elements included in the power circuit, and the control device, when a speed of the electric motor is higher than a threshold speed, generates the voltage command at a frequency determined by the speed of the electric motor, and, when the speed of the electric motor is lower than or equal to the threshold speed, generates the voltage command at a frequency determined by a value of a natural frequency of at least one element of the electric motor, a value of the natural frequency of the oscillating element, or the value of the natural multiple of the rotation frequency of the rotator, and with an amplitude that is smaller than an amplitude of the voltage command generated when the speed of the electric motor is higher than the threshold speed, wherein the natural number of the multiple is two or greater. [6] A drive device according to claim 3 or 5, wherein the control means interrupts a supply of AC power to the electric motor when the deterioration determining means determines that deterioration occurs in the at least one element or the vibrating element. [7] Drive device according to one of claims 1 to 6, wherein the power circuit outputs to an electric motor included in the load a current including a current component having a frequency determined by a value of a natural multiple of a rotational frequency of a rotor or a shaft that is the rotator included in the electric motor, the natural number of the multiple being two or greater. [8] Drive device according to one of claims 1 to 7, wherein the deterioration determining means determines any deterioration of the at least one element or the vibrating element based on the value of the frequency spectrum at the natural frequency specified by the frequency domain data and a threshold spectrum defined for each of the at least one element and the vibrating element. [9] Drive device according to claim 8, wherein the at least one element of the load comprises a plurality of elements, and the power circuit outputs a current comprising a current component having a frequency determined by a value of the natural frequency of one of the plurality of elements or of the oscillating element or by the value of the natural multiple of the rotation frequency of the rotatable rotator which is one of the plurality of elements, the power circuit changes the frequency of the current component for each determination period, which is a period for determining deterioration, and the deterioration determining means determines deterioration of the plurality of elements and the vibrating element based on the value of the frequency spectrum indicated by the frequency domain data at the natural frequency or the rotation frequency used to determine the frequency of the current component and the threshold spectrum defined for each of the plurality of elements and the vibrating element. [10] Drive device according to one of claims 1 to 9, wherein the drive device is mountable on a rail vehicle and has a plurality of power circuits, each of which outputs to an electric motor included in one of a plurality of different loads a current comprising a current component having a frequency determined by a natural frequency of at least one element of the electric motor or of the oscillating element corresponding to the electric motor, which oscillates upon receiving an oscillation resulting from an electromagnetic excitation force generated in the electric motor, or by a value of a natural multiple of a rotational frequency of a rotatable rotator, which is one of the at least one element, and the deterioration determining means generates the frequency domain data based on a sensor signal output from a vibration sensor for measuring a vibration amount of the electric motor receiving a power supply from a corresponding power circuit of the plurality of power circuits or a vibration amount of the vibrating element corresponding to the electric motor, and determines any deterioration of the at least one element of the electric motor or the vibrating element based on a value of a frequency spectrum indicated by the frequency domain data for the electric motor or the vibrating element at the natural frequency or the rotation frequency used to determine the frequency of the current component. [11] Deterioration determination method, comprising: Generating frequency domain data based on a sensor signal output from a vibration sensor for measuring a vibration magnitude of a load receiving a power supply from a power circuit or a vibration magnitude of a vibrating element, wherein the power circuit is configured to output a current including a current component having a frequency determined by a natural frequency of at least one element of the load or the vibrating element that vibrates upon receiving a vibration resulting from an electromagnetic excitation force generated in the load, or by a value of a natural multiple of a rotation frequency of a rotatable rotator that is one of the at least one element; and Determining any deterioration of the at least one element of the load or the vibrating element based on a value of a frequency spectrum indicated by the frequency domain data at the natural frequency or the rotational frequency used to determine the frequency of the current component.

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