JP2019205243A - Inverter device - Google Patents

Abstract

To detect defective installation of a rotary machine in an inverter device that performs current feedback control.SOLUTION: An inverter device (1) comprises a power conversion unit that outputs a three-phase AC voltage to a rotary machine, based on a three-phase current detection value detected at an output side of the power conversion unit, a rotational speed of the rotary machine, and a current command value, a control unit that generates a three-phase voltage command value, generates a PWM signal from the three-phase voltage command value, and outputs the PWM signal to the power conversion unit, and a diagnosis unit (19) to which the three-phase voltage command value, an output frequency and the rotational speed are input, the diagnosis unit (19) has an FFT unit (191) that outputs frequency information by performing a fast Fourier transform on at least one-phase voltage command value of the three-phase voltage command value or the three-phase voltage command value, a characteristic frequency calculation unit (192) that calculates and outputs a characteristic frequency from the output frequency and the rotational speed, and a determination unit (193) for determining whether or not a voltage level at the characteristic frequency of the frequency information exceeds a set voltage threshold.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an inverter device.

  Conventionally, an inverter device that drives a rotating machine connected to an output by outputting three-phase AC power to the rotating machine is widely known. V / f control and vector control are widely known as such inverter device control methods. V / f control is open loop control in which the ratio of the output voltage to the output frequency, which is the frequency of the output voltage of the inverter device, is constant. Vector control is control for correcting the actual speed of the rotating machine so as to match the command, and is divided into vector control with sensors and sensorless vector control. In vector control with a sensor, control is performed so that a detection value from a rotation speed detector, which is a sensor of a rotating machine, matches a command value. Patent Document 1 discloses an example of sensor-equipped vector control technology. In sensorless vector control, control is performed so that the rotational speed of the rotating machine estimated from information such as a command value matches the command value. In the vector control, current feedback control is performed in which an inverter current value is detected and a current command value is generated and controlled based on the detected inverter current value.

  By the way, when installation failure occurs in such a rotating machine, miscoupling or misalignment occurs. If the operation is continued in a state where miscoupling or misalignment occurs in the rotating machine, a bearing failure may occur. Therefore, there is a demand for a technique for detecting defective installation of a rotating machine.

  For example, a technique is known in which vibration data is acquired by measuring vibration of a rotating machine, and an abnormality due to improper installation is detected from the frequency component of the vibration data. However, such a technique cannot be applied to a rotating machine installed at a position where vibration measurement is difficult. Examples of positions where vibration measurement is difficult include underwater and nuclear power plants.

  Patent Document 2 as an example of the prior art discloses a technique for diagnosing abnormality of an induction motor and an inverter using a harmonic component of an input voltage detection value or a current detection value of each phase of a rotating machine. Has been. With this technology, it is possible to diagnose an abnormality of installation failure regardless of the installation position of the rotating machine.

JP 2001-78486 A JP 2003-75516 A

  However, the technique disclosed in Patent Document 2 has a problem that it is difficult to apply to an inverter device that performs current feedback control. This is because the motor input voltage, that is, the inverter output voltage, is not a sine wave but a square wave that includes harmonic components, that is, a PWM (Pulse Width Modulation) waveform. This is because the accuracy is low. Or, when the abnormality diagnosis is performed using the current detection value of the rotating machine, the current characteristic frequency component caused by the installation failure is also suppressed to the current value in the normal state by performing the current feedback control. Therefore, it is difficult to diagnose normally.

  This invention is made | formed in view of the above, Comprising: It aims at providing the technique which detects the installation defect of a rotary machine in the inverter apparatus which performs electric current feedback control.

  The present invention that solves the above-described problems and achieves the object includes a power converter that outputs a three-phase AC voltage to a rotating machine, a three-phase current detection value detected on the output side of the power converter, A control unit that generates a three-phase voltage command value based on the rotational speed and the current command value, generates a PWM signal from the three-phase voltage command value, and outputs the PWM signal to the power conversion unit, and the three-phase voltage command value, output A diagnosis unit to which the frequency and the rotation speed are input, and the diagnosis unit performs a fast Fourier transform on the voltage command value of at least one of the three-phase voltage command value and the three-phase voltage command value to obtain a frequency. An FFT unit that outputs information, a characteristic frequency calculation unit that calculates and outputs a characteristic frequency from the output frequency and the rotation speed, and a voltage level at the characteristic frequency of the frequency information is a set voltage threshold value. Whether or not An inverter device and a determining unit for constant for.

  The inverter device of the present invention having the above-described configuration may include a rotation speed estimation unit that estimates the rotation speed of the rotating machine and outputs a rotation speed estimation value, and the rotation speed may be the rotation speed estimation value.

  Alternatively, in the inverter device of the present invention configured as described above, the rotating machine is provided with a rotation speed detector that detects the rotation speed of the rotating machine and outputs a rotation speed detection value, and the rotation speed is the rotation speed. Any number detection value may be used.

  In the inverter device according to the present invention having the above-described configuration, the determination unit may be improperly installed when the voltage level at the characteristic frequency exceeds the set voltage threshold value in any one phase of the frequency information. What is necessary is just to determine that there exists.

  Alternatively, the present invention is based on a power converter that outputs three-phase AC power to a rotating machine, a three-phase current detection value that is detected on the output side of the power converter, the rotational speed of the rotating machine, and a current command value. A controller that generates a three-phase voltage command value, generates a PWM signal from the three-phase voltage command value, and outputs the PWM signal to the power converter; and at least one of the three-phase voltage command value or the three-phase voltage command value A voltage command value for one phase, a current detection value for the same phase as the voltage command value, an output frequency, the rotation speed, and a diagnosis unit to which control method information for the rotating machine is input, the diagnosis unit, When the control method of the rotating machine is a current feedback method, the three-phase voltage command value or the voltage command value is fast Fourier transformed, or when the control method of the rotating machine is a V / f control method, Current detection value is subjected to fast Fourier transform and frequency An FFT unit that outputs information, a characteristic frequency calculation unit that calculates and outputs a characteristic frequency from the output frequency and the rotation speed, and a voltage level at the characteristic frequency of the frequency information according to a control method of the rotating machine Alternatively, the inverter device includes a determination unit that determines whether the current level exceeds a set voltage threshold value or current threshold value.

  In the inverter device of the present invention having the above-described configuration, the characteristic frequency may be a value obtained by adding the rotation frequency of the rotating machine to the output frequency or a value obtained by subtracting the rotation frequency of the rotating machine from the output frequency.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that the installation defect of a rotary machine can be detected in the inverter apparatus which performs electric current feedback control.

It is a block diagram which shows the structure which is connected to the inverter apparatus which concerns on Embodiment 1, and this inverter apparatus. It is a figure which shows the structure of the inverter apparatus which performs vector control shown in FIG. It is a figure which shows the structure of the diagnostic part shown in FIG. It is a figure which shows the FFT waveform of the electric current detection value of the inverter apparatus which performs V / f control. It is a figure which shows the FFT waveform of the electric current detection value of the inverter apparatus which performs electric current feedback control. It is an FFT waveform of the voltage command value of the inverter apparatus which performs current feedback control. It is a figure which shows the structure of the inverter apparatus which concerns on Embodiment 2. FIG. It is a figure which shows the structure of the diagnostic part with which the inverter apparatus shown in FIG. 7 is provided. It is a figure which shows the structure of the diagnostic part with which the inverter apparatus which concerns on Embodiment 3 is provided.

  Embodiments of the present invention will be described below with reference to the drawings. However, this invention is not limitedly interpreted by description of the following embodiment.

<Embodiment 1>
FIG. 1 is a block diagram illustrating an inverter device 1 according to the present embodiment and a configuration connected to the inverter device 1. FIG. 1 shows an inverter device 1, a three-phase AC power source 2 connected to the input side of the inverter device 1, and a rotating machine 3 connected to the output side of the inverter device 1. The inverter device 1 has a function of making the output voltage, that is, the frequency of the voltage applied to the rotating machine 3 variable.

The rotating machine 3, the rotation speed detector 31 that outputs a detection to the rotation speed detection value N _d the rotational speed of the rotating machine 3 is installed. The rotation speed detector 31 is a rotary encoder, and this rotary encoder may be an incremental method or an absolute method. The angle detection of the rotary encoder is not limited to a specific method, and may be a photoelectric method or a magnetic method.

  FIG. 2 is a diagram illustrating a configuration of the inverter device 1 that performs the vector control illustrated in FIG. 1. The inverter device 1 illustrated in FIG. 2 includes a power conversion unit 11, a current detector 12, a rotation speed estimation unit 13, a rotation speed switching unit 14, a current coordinate conversion unit 15, and an FB (Feedback) control unit 16. The voltage coordinate conversion unit 17, the PWM signal generation unit 18, and the diagnosis unit 19 are provided. The current coordinate conversion unit 15, the FB control unit 16, the voltage coordinate conversion unit 17, and the PWM signal generation unit 18 are collectively referred to as the control unit 10.

  The power conversion unit 11 converts the three-phase AC power of the three-phase AC power source 2 into three-phase AC power having different frequencies and outputs the three-phase AC power to the rotating machine 3. The power conversion unit 11 includes a rectifier circuit that converts alternating current into direct current, and an inverter circuit that converts this direct current into alternating current. The rectifier circuit of the power conversion unit 11 is realized by six rectifier elements in which a series circuit in which two rectifier elements are connected in series is provided for each of the U phase, the V phase, and the W phase. The inverter circuit of the power conversion unit 11 is realized by six switching elements, in which a series circuit in which two switching elements are connected in series is provided for each of the U phase, the V phase, and the W phase.

The current detector 12 detects and outputs the U-phase current detection value i _u , the V-phase current detection value _iv, and the W-phase current detection value i _w from the output of the power conversion unit 11. The current detector 12 is realized by three current sensors provided corresponding to the U phase, V phase, and W phase. Incidentally, it referred to as three-phase current detection value _{i uvw} together U-phase current detection value _i u, V-phase current detection value _{i v,} and W-phase current detection value _{i w.}

Rotational speed estimation unit 13 outputs the rotational speed estimation value N _e based on the current-voltage information of the inverter device 1. Here, the current / voltage information includes a voltage command value, a current command value, a voltage detection value, or a current detection value.

The rotation speed switching unit 14 receives the rotation speed detection value N _d and the rotation speed estimation value N _e as inputs, and outputs either the rotation speed detection value N _{d or the} rotation speed estimation value N _e . In the following description, the rotational speed detection value N _d and the rotational speed estimation value N _e are referred to as the rotational speed N. When the rotational speed switching unit 14 outputs the rotational speed detection value N _d , the rotational speed N is a rotation speed detection value N _d, in the case where the rotation speed switching unit 14 outputs a rotation speed detection value N _e is the rotation speed N is the rotational speed detection value N _e.

In the inverter device 1, when only the rotational speed estimation value _Ne is used as the rotational speed N, that is, when the control method of the inverter device 1 is sensorless vector control, the rotational speed switching unit 14 and the rotational speed detector. 31 may not be provided. Alternatively, in the inverter device 1, when only the rotation speed detection value N _d is used as the rotation speed N, that is, when the control method of the inverter device 1 is vector control with a sensor, the rotation speed estimation unit 13 and the rotation speed switching are performed. The part 14 may not be provided.

The current coordinate conversion unit 15 receives the rotation speed N and the three-phase current detection value i _uvw and outputs a dq-axis current detection value i _dq . The current coordinate conversion unit 15 converts the three-phase current detection value i _uvw into the dq-axis current detection value i _dq based on the rotation speed N. The dq-axis current detection value i _dq includes a d-axis current detection value i _d and a q-axis current detection value i _q .

FB control unit 16 inputs the dq-axis current detection value _{i dq} and dq-axis current command value _{I dq,} PI (Proportional Integral) outputs a dq-axis voltage command value _{V dq} by the control. The dq-axis current command value I _dq includes a d-axis current command value I _d and a q-axis current command value I _q , and the dq-axis voltage command value V _dq is a d-axis voltage command value V _d and a q-axis voltage command value V _q is included. The d-axis voltage command value V _d is determined so that the deviation between the d-axis current detection value i _d and the d-axis current command value I _d is zero, and the q-axis voltage command value V _q is the q-axis current detection value. The deviation between i _q and q-axis current command value I _q is determined to be zero. However, the present invention is not limited to this, and the FB control unit 16 may perform P (Proportional) control or PID (Proportional-Integral-Differential) control.

Note that the dq-axis current command value I _dq is a value calculated based on an external rotating machine speed command value or torque command, for example, in a calculation unit (not shown).

The voltage coordinate conversion unit 17 receives the rotational speed N and the dq axis voltage command value V _dq and outputs a three-phase voltage command value V _uvw . The voltage coordinate conversion unit 17 converts the dq axis voltage command value V _dq into a three-phase voltage command value V _uvw . The three-phase voltage command value V _uvw includes a U-phase voltage command value V _u , a V-phase voltage command value V _v, and a W-phase voltage command value V _w . Further, the voltage coordinate conversion unit 17 outputs an output frequency _fe . The output frequency _fe is a preset output frequency of the inverter device 1 and a frequency of the three-phase voltage command value V _uvw .

The PWM signal generation unit 18 receives the three-phase voltage command value V _uvw as input, and generates and outputs a PWM signal based on the three-phase voltage command value V _uvw . This PWM signal is a gate signal of a switching element provided in the inverter circuit unit of the power conversion unit 11, controls on / off of the switching element, and controls the output of the inverter device 1.

The diagnosis unit 19 receives the three-phase voltage command value V _uvw , the rotation speed N, and the output frequency _fe and outputs a determination result. The output frequency _fe is output from the voltage coordinate conversion unit 17, but may be a detection value in the output of the power conversion unit 11.

  FIG. 3 is a diagram showing a configuration of the diagnosis unit 19 shown in FIG. The diagnosis unit 19 illustrated in FIG. 3 includes an FFT (Fast Fourier Transform) unit 191, a characteristic frequency calculation unit 192, and a determination unit 193.

FFT section 191 inputs the three-phase voltage command value _{V uvw,} and outputs the frequency information _{f uvw.} The FFT unit 191 calculates each frequency component of the three-phase voltage command value V _uvw by fast Fourier transform, and generates frequency information f _uvw . The frequency information f _uvw includes U-phase frequency information f _u , V-phase frequency information f _v and W-phase frequency information f _w .

The characteristic frequency calculation unit 192 receives the rotation speed N and the output frequency _fe and outputs a characteristic frequency f _err . Wherein the frequency calculation unit 192 first calculates a rotating machine rotation frequency f _r from the rotation speed N. In the case where the rotating machine 3 is an induction machine, the rotating machine rotation frequency f _r (Hz) is _{expressed by} the following formula using the rotation number N (min ⁻¹ ) of the rotating machine 3 and the pole pair number P of the rotating machine 3 ( It is calculated by 1).

Then, the characteristic frequency calculation unit 192 calculates the characteristic frequency f _{err according} to the following equation (2) using the rotating machine rotation frequency f _r and the output frequency _fe .

The determination unit 193 receives the frequency information f _uvw and the characteristic frequency f _err and outputs a determination result. The determination unit 193 compares the level at the characteristic frequency of the three-phase voltage command value V _uvw with a threshold value, and determines that this level is “normal” if the level is smaller than the voltage threshold value. If it is larger than the value, it is determined as “abnormal”. Here, the voltage threshold value is a preset value.

  The determination unit 193 performs this determination for each of the U phase, the V phase, and the W phase, and determines that the determination result is “abnormal” if any one of these three phases is abnormal. As described above, determination is made for each of the U phase, the V phase, and the W phase, and if any of the phases is abnormal, the determination result is set to “abnormal”, thereby enabling a highly accurate diagnosis. .

  In addition, this determination result is alert | reported to a user or an administrator by outputting to the output part mounted in the inverter apparatus 1, or connected, for example. Here, as the output unit, a display can be exemplified. Or this determination result may be output to the inverter stop part which is the structure which is not shown in figure, and the structure which the inverter apparatus 1 forcibly stops at the time of abnormality may be sufficient.

Here, the current FFT waveform included in the above-described frequency information f _uvw when there is an improper installation of the rotating machine will be described. FIG. 4 is a diagram illustrating an FFT waveform of a current detection value of an inverter device that performs V / f control when current feedback control is not performed. Here, if the operating conditions are the rotating machine rotation frequency f _r = 25 Hz and the output frequency f _e = 50 Hz, the characteristic frequencies f _err = 25 Hz and 75 Hz. In FIG. 4, the waveform when there is an installation failure is indicated by a solid line, and the waveform when there is no installation failure is indicated by a broken line. As shown in FIG. 4, when there is a faulty installation of the rotating machine, the level is increased at the characteristic frequency f _err = 25 Hz, 75 Hz, so that an abnormality can be determined by setting an appropriate threshold value. It is.

However, when current feedback control is performed, that is, when vector control is performed, the current characteristic frequency component caused by installation failure is also suppressed to a current value in a normal installation state. FIG. 5 is a diagram illustrating an FFT waveform of a current detection value of an inverter device that performs current feedback control. In FIG. 5, the waveform when there is an installation failure is indicated by a solid line, and the waveform when there is no installation failure is indicated by a broken line. As shown in FIG. 5, when the current feedback control is performed, the current is suppressed even at the characteristic frequency f _err , so that the installation failure of the rotating machine cannot be determined from the current FFT waveform.

Therefore, the FFT waveform of the voltage command value is used as described above. FIG. 6 is an FFT waveform of a voltage command value of an inverter device that performs current feedback control. In FIG. 6, the waveform when there is an installation failure is indicated by a solid line, and the waveform when there is no installation failure is indicated by a broken line. As shown in FIG. 6, when there is a faulty installation of the rotating machine 3, the level increases at the characteristic frequency f _err = 25 Hz, 75 Hz, and an abnormality can be determined by setting an appropriate threshold value. . As described above, when current feedback control is performed, it is possible to determine the presence or absence of installation failure by using the voltage command value.

  As described above, according to the present embodiment, even when current feedback control is performed, it is possible to detect an improper installation of the rotating machine regardless of the installation position of the rotating machine.

<Embodiment 2>
Although Embodiment 1 demonstrated the form which detects the installation defect of a rotary machine when an inverter apparatus is a current feedback control system, this invention is not limited to this. In the present embodiment, an inverter device capable of detecting a rotating machine installation failure regardless of the control method of the inverter device will be described.

FIG. 7 is a diagram showing a configuration of the inverter device 1a according to the present embodiment. The inverter device 1a shown in FIG. 7 includes a voltage coordinate conversion unit 17a instead of the voltage coordinate conversion unit 17, a diagnosis unit 19a instead of the diagnosis unit 19, and a voltage command switching unit 20 added. The point which outputs the output frequency _fe from the switch part 20 differs from the inverter apparatus 1 shown in FIG. 1, and since the other structure is the same as that of the inverter apparatus 1 shown in FIG. 1, description of Embodiment 1 is used. The current coordinate conversion unit 15, the FB control unit 16, the voltage coordinate conversion unit 17a, the PWM signal generation unit 18, and the voltage command switching unit 20 are collectively referred to as a control unit 10a. 7 operates in the same manner as the inverter device 1 shown in FIG. 1 when the rotating machine control method is vector control.

Voltage coordinate converter 17a receives as input the rotational speed N and the dq-axis voltage command value Vdq, converts the dq axis voltage command values _{V dq} to three-phase voltage command value _{V Uvw1,} and outputs the three-phase voltage command value _{V Uvw1} . The three-phase voltage command value V _uvw1 includes a U-phase voltage command value V _u1 , a V-phase voltage command value V _v1, and a W-phase voltage command value V _w1 .

The diagnosis unit 19a receives the three-phase voltage command value V _uvw , the rotation speed N, the output frequency _fe, and the three-phase current detection value i _uvw and outputs a determination result. The output frequency _fe is output from the voltage coordinate conversion unit 17a, but may be a detected value in the output of the power conversion unit 11.

The voltage command switching unit 20 receives the three-phase voltage command value V _uvw1 and the three-phase voltage command value V _uvw2 and outputs the three-phase voltage command value V _uvw . Here, the voltage command switching unit 20 outputs the three-phase voltage command value V _uvw1 as the three-phase voltage command value V _uvw when the inverter device 1a is in current feedback control, and the inverter device 1a performs the V / f control. and outputs the three-phase voltage command value _{V Uvw2} as a three-phase voltage command value _{V uvw} in some cases. Further, the three-phase voltage command value V _uvw2 is a value calculated based on a rotating machine speed command value or a torque command from the outside, for example, in a calculation unit (not shown). The three-phase voltage command value V _uvw2 includes a U-phase voltage command value V _u2 , a V-phase voltage command value V _v2, and a W-phase voltage command value V _w2 . Moreover, the voltage command switching unit 20 outputs the set output frequency _fe . The output frequency _fe is the frequency of the three-phase voltage command value V _uvw as in the first embodiment.

  FIG. 8 is a diagram illustrating a configuration of a diagnosis unit 19a included in the inverter device 1a illustrated in FIG. The diagnosis unit 19a illustrated in FIG. 8 includes an FFT unit 191a, a characteristic frequency calculation unit 192, and a determination unit 193a.

The FFT unit 191a receives the three-phase voltage command value V _uvw , the three-phase current detection value i _uvw, and the rotating machine control method information, and outputs frequency information f _uvw . The rotating machine control method can be switched by the user using an external switch or the like, and the rotating machine control method information is output from the external switch or the like. When the rotating machine control method is current feedback control, the FFT unit 191a generates frequency information f _uvw by calculating each frequency component of the three-phase voltage command value V _uvw by fast Fourier transform. Alternatively, when the control method is not the current feedback control method but V / f control, the FFT unit 191a calculates the frequency information f _uvw by calculating each frequency component of the three-phase current detection value i _uvw by fast Fourier transform. Is generated.

The determination unit 193a receives the frequency information f _uvw , the characteristic frequency f _err and the rotating machine control method information, and outputs a determination result. The determination unit 193a operates in the same manner as the determination unit 193 of the first embodiment when the rotating machine control method is current feedback control. That is, the voltage level at the characteristic frequency of the three-phase voltage command value V _uvw is compared with the voltage threshold value, and when this voltage level is smaller than the voltage threshold value, it is determined as “normal”, If it is greater than the voltage threshold, it is determined as “abnormal”. Here, the voltage threshold value is a preset value. Alternatively, the determination unit 193a _compares the current level at the characteristic frequency of the three-phase current detection value i _uvw and the current threshold when the rotating machine control method is not current feedback control but V / f control. When the current level is smaller than the current threshold, it is determined as “normal”, and when the current level is higher than the current threshold, it is determined as “abnormal”. Here, the current threshold value is a preset value.

  The determination unit 193a performs this determination for each of the U phase, the V phase, and the W phase regardless of the rotating machine control method. If any one of these three phases is abnormal, the determination result is “ "Abnormal". As described above, determination is made for each of the U phase, the V phase, and the W phase, and if any of the phases is abnormal, the determination result is set to “abnormal”, thereby enabling a highly accurate diagnosis. . Further, this determination result is output in the same manner as in the first embodiment and is notified to the user or the administrator. Or this determination result may be output to the inverter stop part which is not illustrated.

  As described above, according to this embodiment, it is possible to detect an installation failure of a rotating machine regardless of the installation position and control method of the rotating machine.

<Embodiment 3>
In the first embodiment, the form of performing fast Fourier transform on the three-phase voltage command value has been described. In the second embodiment, the form of performing fast Fourier transform on the three-phase voltage command value or the three-phase current detection value has been described. It is not limited. In the present embodiment, a mode in which the U-phase voltage command value or the U-phase current detection value is fast Fourier transformed will be described. In the present embodiment as well, similarly to the second embodiment, it is possible to detect an improper installation of the rotating machine regardless of the control method of the inverter device.

  In the inverter device according to the present embodiment, the configuration other than the diagnosis unit is the same as that of the second embodiment, and therefore the description of the first and second embodiments is used for the other configurations.

  FIG. 9 is a diagram illustrating a configuration of a diagnosis unit 19b included in the inverter device according to the present embodiment. The diagnosis unit 19b illustrated in FIG. 9 includes an FFT unit 191b, a characteristic frequency calculation unit 192, and a determination unit 193b.

The FFT unit 191b receives the U-phase voltage command value V _u , the U-phase current detection value i _u and the rotating machine control method information, and outputs U-phase frequency information f _u . When the rotating machine control method is current feedback control, the FFT unit 191b calculates the frequency component of the U-phase voltage command value V _u by fast Fourier transform to generate U-phase frequency information f _u . Or, rather than in a controlled manner the current feedback control scheme by fast Fourier transform, in the case of V / f control, FFT section 191b is computed by fast Fourier transform on the frequency components of the U-phase current detection value i _u U The phase frequency information _fu is generated.

The determination unit 193b receives the U-phase frequency information f _u , the characteristic frequency f _err, and the rotating machine control method information, and outputs a determination result. When the rotating machine control method is current feedback control, the determination unit 193b compares the voltage level at the characteristic frequency of the U-phase voltage command value _Vu with the voltage threshold, and the voltage level is the voltage threshold. If it is smaller than this, it is determined as “normal”, and if this level is higher than the voltage threshold, it is determined as “abnormal”. Here, the voltage threshold value is a preset value. Alternatively, when the rotating machine control method is not current feedback control but V / f control, the determination unit 193b compares the current level at the characteristic frequency of the U-phase current detection value _iu with the current threshold value. When the current level is smaller than the current threshold, it is determined as “normal”, and when the current level is higher than the current threshold, it is determined as “abnormal”. Here, the current threshold value is a preset value.

  In addition, the determination result of the determination part 193b is output similarly to Embodiment 1, 2, and alert | reports to a user or an administrator. Or this determination result may be output to the inverter stop part which is not illustrated.

Moreover, you may combine this embodiment and Embodiment 1. FIG. That is, the diagnosis unit provided in the inverter device shown in FIG. 2 may be configured to input the U-phase voltage command value V _u , the rotation speed N, and the output frequency _fe to output a determination result.

  In addition, although this embodiment illustrated and demonstrated the form which fast-transforms only a U phase, this embodiment is not limited to this, It replaces with a U phase and fast Fourier transforms a V phase. Alternatively, the W phase may be fast Fourier transformed instead of the V phase. Thus, if it is set as the structure which performs a fast Fourier transformation only about any one phase among three phases, the structure simplification of an inverter apparatus and the simplification of a process will be attained.

  As described above, according to the present embodiment, it is possible to detect an improper installation of the rotating machine by performing a fast Fourier transform on any one of the three phases regardless of the installation position and control method of the rotating machine. it can.

DESCRIPTION OF SYMBOLS 1, 1a Inverter apparatus 2 Three-phase alternating current power supply 3 Rotating machine 10, 10a Control part 11 Power conversion part 12 Current detector 13 Speed estimation part 14 Speed change part 15 Current coordinate conversion part 16 FB control part 17, 17a Voltage coordinate Conversion unit 18 PWM signal generation unit 19, 19a, 19b Diagnosis unit 191, 191a, 191b FFT unit 192 Characteristic frequency calculation unit 193, 193a, 193b Determination unit 20 Voltage command switching unit 31 Rotation speed detector

Claims (6)

A power converter that outputs a three-phase AC voltage to the rotating machine;
A three-phase voltage command value is generated based on the detected three-phase current value detected on the output side of the power converter, the rotational speed of the rotating machine, and a current command value, and a PWM signal is generated from the three-phase voltage command value. A control unit that outputs to the power conversion unit,
A diagnostic unit to which the three-phase voltage command value, the output frequency and the rotation speed are input,
The diagnostic unit
An FFT unit that outputs frequency information by fast Fourier transforming the voltage command value of at least one of the three-phase voltage command value or the three-phase voltage command value;
A characteristic frequency calculator that calculates and outputs a characteristic frequency from the output frequency and the rotation speed;
An inverter apparatus comprising: a determination unit that determines whether a voltage level at the characteristic frequency of the frequency information exceeds a set voltage threshold value. A rotation speed estimation unit that estimates the rotation speed of the rotating machine and outputs a rotation speed estimation value;
The inverter apparatus according to claim 1, wherein the rotational speed is the rotational speed estimated value. The rotation machine is provided with a rotation speed detector that detects the rotation speed of the rotation machine and outputs a rotation speed detection value.
The inverter device according to claim 1, wherein the rotation speed is the rotation speed detection value.   2. The determination unit according to claim 1, wherein, in any one phase of the frequency information, the determination unit determines that the installation is defective when a voltage level at the characteristic frequency exceeds the set voltage threshold value. Inverter device. A power converter that outputs three-phase AC power to a rotating machine;
A three-phase voltage command value is generated based on the detected three-phase current value detected on the output side of the power converter, the rotational speed of the rotating machine, and a current command value, and a PWM signal is generated from the three-phase voltage command value. A control unit that outputs to the power conversion unit,
At least one of the three-phase voltage command value or the three-phase voltage command value, the current detection value of the same phase as the voltage command value, the output frequency, the rotation speed, and the control method of the rotating machine A diagnostic unit for inputting information,
The diagnostic unit
When the control method of the rotating machine is a current feedback method, the three-phase voltage command value or the voltage command value is fast Fourier transformed, or when the control method of the rotating machine is a V / f control method An FFT unit that outputs frequency information by performing a fast Fourier transform on the detected current value;
A characteristic frequency calculator that calculates and outputs a characteristic frequency from the output frequency and the rotation speed;
A determination unit that determines whether a voltage level or a current level at the characteristic frequency of the frequency information exceeds a set voltage threshold or current threshold according to a control method of the rotating machine; An inverter device provided.   The said characteristic frequency is the value which added the rotational frequency of the said rotary machine to the said output frequency, or the value which subtracted the rotational frequency of the said rotary machine from the said output frequency. Inverter device.

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