JP3949634B2 - Method and apparatus for measuring rotational vibration of rotating body - Google Patents

Description

  The present invention relates to a method and apparatus for measuring rotational vibration of a rotating body, and more particularly to a method and apparatus for measuring rotational vibration of a rotor of a main motor of a vehicle.

  FIG. 4 is a schematic view of a conventional railway vehicle drive device.

  In these drawings, 101 is a main motor, 102 is an output rotating shaft of the main motor 101, 103 is a joint connected to the output rotating shaft 102, 104 is a small gear fixed to the joint 103, and 105 is a small gear. 104 is a gear box meshed with 104, 106 is a gear box, 107 is an axle driven by the large gear 105, 108 is a wheel fixed to the axle 107, 109 is an axle box provided at both ends of the axle 107, and 110 is a main motor 101 is a speed generator provided in 101.

For example, when a train running on a Shinkansen vehicle equipped with such a railway vehicle drive device is traveling at high speed, low-frequency noise (about 250 Hz) may be heard in the vehicle, and the noise level may increase by about 3 dB. The cause of this noise is not yet clear, but the torsional vibration of the system of the main motor rotor (not shown) from the small gear 104 is swung around the gear-type flexible shaft joint 103 between the main motor 101 and the gear devices 104 and 105. (Rotational vibration), and vibrations including the bogie frame and the drive system are estimated as causes. Among these presumed causes, the torsional vibration (rotational vibration) of the main motor rotor needs to be measured in a non-contact manner because the object to be measured is a rotating body, and it is difficult to select a measurement method and to measure in a running test.
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  As described above, the torsional vibration of the main motor rotor of the vehicle needs to be measured in a non-contact manner because the object to be measured is a rotating body. However, it is difficult to select a measurement method, and measurement in a running test is also difficult. Therefore, paying attention to the output of the speed generator attached to the main motor, an attempt was made to measure the torsional vibration of the main motor rotor based on the output.

  However, the frequency fluctuation of the AC voltage output from the speed generator is very small, and since the DC voltage is smoothed after normal FV conversion, it is difficult to measure the minute frequency fluctuation. .

  In view of the above circumstances, an object of the present invention is to provide a rotational vibration measuring method and apparatus for a rotating body that can measure torsional vibration of a main motor rotor with a simple device.

In order to achieve the above object, the present invention provides
[1] In the rotational vibration measuring method of a rotating body, (a) an AC voltage output of a speed generator is input to a PLL circuit having a time constant of 100 times or more of an AC voltage cycle, and the voltage controlled oscillator of the PLL circuit An average zero-cross interval of the output of the speed generator is obtained from the output; (b) a variation of the zero-cross interval that is a time-varying component of the output of the speed generator is obtained with reference to the zero-cross interval of the output of the PLL circuit; (c) The average zero-crossing interval of the speed generator output obtained in (a) is used as a sampling interval, and (d) time-series data obtained in (b) is subjected to digital low-pass filter to reduce aliasing. (E) Fast Fourier transform (FFT) is performed on the time-series data of the time-varying component, the magnitude of the frequency component included in the time-varying component is obtained, and the PLL circuit Frequency based on the average zero crossing interval, and displaying normalized magnitude.

  [2] In the rotational vibration measuring apparatus for a rotating body, a speed generator to be measured having the rotating body, a PLL circuit having a time constant of 100 times or more of the cycle of the AC voltage connected to the speed generator, A means for measuring the zero cross interval of the output waveform of the speed generator and a comparison connected to the output side of the voltage controlled oscillator of the PLL circuit and comparing the average zero cross interval as the output of the voltage controlled oscillator with the zero cross interval And a digital low-pass filter connected to the comparator; a fast Fourier transformer connected to the output side of the voltage-controlled oscillator of the PLL circuit and connected to the digital low-pass filter; The AC voltage output of the machine is input to the PLL circuit to obtain the average zero cross interval of the output of the speed generator, and the output of the PLL circuit is zero Based on the loss interval, the fluctuation of the zero cross interval, which is the time fluctuation component of the output of the speed generator, is obtained, the average zero cross interval is made the sampling interval, and the time series data of the time fluctuation component is aliased by applying a digital low pass filter. And performing fast Fourier transform (FFT) of the time-series data of the time-varying component to obtain the magnitude of the frequency component included in the time-varying component, and the frequency and magnitude based on the average zero-crossing interval of the PLL circuit It is characterized by normalizing and displaying.

  [3] The rotational vibration measuring apparatus for a rotating body according to [2], wherein the measurement target having the rotating body is a main motor of a vehicle.

  [4] The rotational vibration measuring apparatus for a rotating body according to [3], wherein the vehicle is a railway vehicle.

  According to the present invention, in analyzing torsional vibration of the main motor rotor, it is only necessary to analyze the output of the existing speed generator in the main motor of the vehicle, reducing the temporary work for measurement as in the prior art. Can be achieved. Further, it is not necessary to use a high-precision rotation measuring instrument, and the torsional vibration of the main motor rotor can be measured with a simple device.

  The AC voltage output of the speed generator is input to a PLL circuit having a time constant of 100 times or more of the AC voltage cycle, the average zero cross interval of the output signal of the speed generator is obtained, and the average zero cross interval obtained by the PLL circuit is obtained. The fluctuation (time fluctuation component) of the zero-crossing interval of the output signal of the speed generator with reference to is obtained. Next, the average zero-crossing interval of the output of the speed generator is set as a sampling interval, and the digital low-pass filter is applied to the time series data of the time fluctuation component to reduce aliasing, and the fast Fourier transform of the time series data of the time fluctuation component (FFT) is performed, the magnitude of the frequency component included in the time variation component is obtained, and the frequency and magnitude are normalized based on the average zero cross interval of the PLL circuit and displayed. Therefore, the torsional vibration of the rotor of the main motor can be measured with a simple device.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a configuration diagram of a rotational vibration measuring device for a rotating body showing an embodiment of the present invention, FIG. 2 is a configuration diagram of a PLL circuit of the rotational vibration measuring device for the rotating body, and FIG. 3 is a waveform diagram of a speed generator output. is there. In FIG. 3, the thick line is the output waveform of the speed generator when the main motor is rotating at a constant speed, and the zero cross point has a constant interval, whereas the thin line is the fluctuation when the main motor is coasting. This is the output waveform of the speed generator when it is rotating, and has an interval in which the zero cross point fluctuates.

  In FIG. 1, 1 is a main motor, 2 is a speed generator provided in the main motor 1, and 10 is a measurement for measuring torsional vibration of a rotor of the main motor 1 based on AC voltage output data from the speed generator 2. The measuring device 10 includes a PLL circuit 11 that outputs an average zero-cross interval signal of the output waveform of the speed generator 2, a zero-cross interval measuring circuit (sensor) 12 for the output waveform of the speed generator 2, and the PLL circuit 11. The comparator 13 that compares the average zero-cross interval that is output and the zero-cross interval that is actually output; the digital low-pass filter 14 that receives the time-variable component output from the comparator 13; and the output from the digital low-pass filter 14 An FFT (Fast Fourier Transform) analyzer 15 for inputting a signal and a positive signal connected to the FFT (Fast Fourier Transform) analyzer 15 Circuit 16, and a display device 17 connected to the normalization circuit 16.

  Further, the PLL circuit 11 itself has a normal configuration as shown in FIG. 2, and constitutes a closed feedback circuit including a phase comparator 11A, a low-pass filter 11B, an amplifier 11C, and a voltage controlled oscillator 11D. The frequency and phase of the input signal and the oscillation frequency and phase of the voltage controlled oscillator 11D are compared by the phase comparator 11A, and a DC voltage proportional to the error is generated. This error voltage passes through the low-pass filter 11B, is amplified by the amplifier 11C, is added to the voltage controlled oscillator 11D, and the frequency of the voltage controlled oscillator 11D is reduced in a direction that reduces the oscillation frequency and phase difference between the input signal and the voltage controlled oscillator 11D. It is supposed to change. The PLL circuit 11 has a time constant that is 100 times or more the period of the AC voltage.

  Therefore, the AC voltage output of the speed generator 2 provided in the main motor 1 is input to the PLL circuit 11 having a time constant of 100 times or more of the cycle of the AC voltage, and the average zero-crossing interval signal of the output of the speed generator 2 is set as the voltage. Obtained from the output of the controlled oscillator 11D. On the other hand, the output waveform of the speed generator 2 is input to a zero cross interval measuring circuit (sensor) 12 to obtain a zero cross interval signal. Next, the zero cross interval signal and the average zero cross interval signal are compared by the comparator 13. That is, the fluctuation (time fluctuation component) of the zero cross interval signal of the output signal of the speed generator 2 is obtained with reference to the average zero cross interval of the output of the voltage controlled oscillator 11D of the PLL circuit 11. Next, the average zero-crossing interval of the output signal of the speed generator 2 is used as a sampling interval, and the time-varying component time-series data is subjected to a digital low-pass filter 14 to reduce aliasing, and the time-varying component time-series data The fast Fourier transform (FFT) is performed by the fast Fourier transform analyzer 15 to obtain the magnitude of the frequency component included in the time-varying component, and the frequency based on the average zero-crossing interval of the voltage controlled oscillator 11D of the PLL circuit 11 The size is normalized by the normalization circuit 16 and displayed on the display device 17.

  Therefore, the torsional vibration of the main motor rotor can be measured with a simple device.

  As described above, generally, an AC voltage is output from the speed generator 2 attached to the main motor 1 of the vehicle, and is converted into a DC voltage proportional to the speed by performing FV conversion. If it is assumed that the main motor 1 rotor is torsionally vibrated (rotational vibration), it is considered that slight fluctuations occur in the output frequency proportional to the rotational speed of the AC voltage output from the speed generator 2. However, since the frequency fluctuation of the AC voltage is minute and the DC voltage is smoothed after normal FV conversion, it is difficult to measure the minute frequency fluctuation.

  Therefore, according to the present invention, in order to measure the torsional vibration (rotational vibration) from the AC output of the speed generator 2 attached to the main motor 1, the output signal of the speed generator 2 is more than 100 times the cycle of the AC voltage. The average zero-cross interval of the output signal of the speed generator 2 is obtained by inputting to the PLL circuit 11 having the time constant of The frequency analysis of fluctuation is performed.

  In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention.

  The method and apparatus for measuring rotational vibration of a rotating body according to the present invention is particularly suitable for a simple rotational vibration measuring apparatus using a speed generator of a railway vehicle.

It is a block diagram of the rotational vibration measuring apparatus of the rotary body which shows the Example of this invention. It is a block diagram of the PLL circuit of the rotational vibration measuring apparatus of the rotary body which shows the Example of this invention. It is a wave form diagram of the speed generator output which shows the Example of this invention. It is a schematic diagram of the drive device of the conventional railway vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main motor 2 Speed generator 10 Measuring apparatus which measures torsional vibration of rotor 11 PLL circuit 11A Phase comparator 11B Low pass filter 11C Amplifier 11D Voltage controlled oscillator 12 Zero cross interval measuring circuit (sensor)
13 Comparator 14 Digital Low Pass Filter 15 FFT (Fast Fourier Transform) Analyzer 16 Normalization Circuit 17 Display Device

Claims (4)

(A) The AC voltage output of the speed generator is input to a PLL circuit having a time constant of 100 times or more of the AC voltage cycle, and the average zero-crossing interval of the output of the speed generator from the output of the voltage controlled oscillator of the PLL circuit Seeking
(B) Obtaining the fluctuation of the zero cross interval, which is a time fluctuation component of the output of the speed generator, based on the average zero cross interval obtained by the PLL circuit,
(C) The average zero cross interval of the output signal of the speed generator determined in (a) is defined as a sampling interval,
(D) A digital low-pass filter is applied to the time-series data of the fluctuation of the zero-cross interval obtained in (b) to reduce aliasing,
(E) Fast Fourier transform (FFT) is performed on the time-series data of the time-varying component, the magnitude of the frequency component included in the time-varying component is obtained, and the frequency and magnitude are determined based on the average zero-crossing interval of the PLL circuit. A method for measuring rotational vibration of a rotating body, characterized by normalizing and displaying the height. (A) a speed generator to be measured having a rotating body;
(B) a PLL circuit having a time constant of 100 times or more of the cycle of the AC voltage connected to the speed generator;
(C) means for measuring a zero-crossing interval of the output waveform of the speed generator;
(D) a comparator that is connected to the output side of the voltage controlled oscillator of the PLL circuit and compares the average zero cross interval as the output of the voltage controlled oscillator with the zero cross interval;
(E) a digital low-pass filter connected to the comparator;
(F) a fast Fourier transform connected to the output side of the voltage controlled oscillator of the PLL circuit and connected to the digital low pass filter;
(G) An AC voltage output of the speed generator is input to a PLL circuit to obtain an average zero cross interval of the output signal of the speed generator, and an output of the speed generator is based on the average zero cross interval obtained by the PLL circuit. The variation of the zero crossing interval, which is a time variation component of the time variation component, is obtained, the average zero cross interval is defined as the sampling interval, and the time series data of the time variation component is subjected to a digital low-pass filter to reduce aliasing. Performing Fast Fourier Transform (FFT) of the series data, obtaining the magnitude of the frequency component contained in the time-varying component, and normalizing and displaying the frequency and magnitude based on the average zero-cross interval of the PLL circuit. An apparatus for measuring rotational vibrations of a rotating body.   The rotational vibration measuring apparatus for a rotating body according to claim 2, wherein the measurement object having the rotating body is a main motor of a vehicle.   4. The rotational vibration measuring apparatus for a rotating body according to claim 3, wherein the vehicle is a railway vehicle.

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