JP2003143862A - Inverter driven electric rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability of an inverter driven electric rotating machine through a partial discharge measuring circuit device also capable of serving to suppress overvoltage during inverter operation. SOLUTION: Input side of an inverter is insulated from a point of the same potential as the low voltage side of an overvoltage suppression filter and an electric rotating machine, and a current closed circuit connecting the input of the inverter with the overvoltage suppression filter and the electric rotating machine is interrupted, or a magnetic circuit is provided to interlink the three- phase UVW feeder lines between the inverter and the filter, or a magnetic circuit is provided to interlink the three-phase UVW closed circuit connecting the filter with the core of the electric rotating machine, low voltage side of the capacitor or resistor in the filter is connected to a point of the same potential as the core of the electric rotating machine, and a voltage generated in the resistor is measured by means of a partial discharge measuring device comprising a filter having a low frequency side cut-off frequency of 10-100 MHz, and a voltage measuring device having a frequency band of DC-1 GHz or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter-driven rotary electric machine system equipped with a device for diagnosing insulation deterioration while suppressing overvoltage due to surge voltage.

[0002]

2. Description of the Related Art In recent years, inverter operation has been widely applied to rotary electric machines for the purpose of energy saving. However, along with this, an insulation problem has newly occurred in the rotating electric machine due to a steep inverter surge voltage, and it has been studied together with the conventional insulation deterioration problem in a sine wave voltage.

The problem of insulation of a rotating electric machine due to an inverter surge is described in, for example, Technical Report No. 739 of the Institute of Electrical Engineers of Japan, p.
As described in Nos. 12 to 20, there is a problem that the surge voltage is reflected at the connecting portion between the cable and the rotary electric machine, and an overvoltage occurs. Further, when a sharp surge voltage enters the rotating electric machine, a transient phenomenon occurs in the voltage distribution of the rotating electric machine winding, which causes a problem that an overvoltage is generated between the coil windings. Conventionally, for these problems, for example, Hitachi Inverter J100 Catalog p. 27, or Japanese Patent Laid-Open No. 6-38543, measures such as provision of LCR, LC, and CR filters are taken.

On the other hand, regarding the insulation deterioration of the rotating electric machine, the rotating electric machine is stopped during operation or periodically in order to update the insulation or the equipment before the dielectric breakdown occurs.
Insulation deterioration diagnosis is performed. For diagnosis of insulation deterioration during operation, there is, for example, JP-A-6-138168. In recent years, in the insulation deterioration diagnosis of rotating electrical machines, partial discharge measurement is mainly performed. For this method, for example, Technical Report of the Institute of Electrical Engineers of Japan (Part II) No. 402, p. 27 to 35, there are a coupling capacitor method, a ground wire current detection method, an ultrasonic method, a radiation electromagnetic field method, a light emission detection method and the like.

[0005]

By the way, conventionally, suppression of overvoltage against these surge voltages and insulation deterioration diagnosis have been performed separately.

An object of the present invention is to provide a highly reliable inverter driven rotating electric machine system that simultaneously realizes suppression of overvoltage and insulation deterioration diagnosis.

[0007]

Therefore, the inventor connected an overvoltage suppressing filter and a partial discharge measuring device to a rotating electric machine and attempted to simultaneously realize suppression of overvoltage and diagnosis of insulation deterioration.
In the partial discharge measurement, the coupling capacitor method, which is widely used for insulation diagnosis of rotating electrical machines, was used. In addition, the partial discharge measuring device includes 40th technical report of the Institute of Electrical Engineers of Japan (Part II).
No. 2, p. 31, a low-frequency partial discharge measuring device (frequency band: about 15 to 16) widely used in rotary electric machines.
0 kHz), a general tuning type partial discharge measuring device (center frequency 400 kHz, bandwidth 90 kHz), and a wide band partial discharge measuring device (frequency band: about 5 kHz to 1 MHz) were used for trial.

However, even if the conventional overvoltage suppressing filter and the partial discharge measuring device are connected to the rotating electric machine, the noise signal caused by the inverter surge is erroneously recognized as the partial discharge even if the overvoltage can be suppressed. I could not measure. Further, compared with the case where the overvoltage suppression filter is not connected, the partial discharge detection sensitivity (the voltage detected by the partial discharge measuring instrument when the partial discharge of 1 pC occurs (unit: V /
pC)) is decreased. Furthermore, it is difficult to perform partial discharge measurement and insulation deterioration diagnosis for each phase because signals of other phases are mixed.

In view of the above situation, the configurations of the overvoltage suppressing filter and the partial discharge measuring device were newly examined. As a result, it has been found that the following inverter driven rotating electrical machine system can achieve the object.

That is, in a rotary electric machine system including a rotary electric machine that transmits and receives electric power from a power supply via an inverter and an overvoltage suppression filter connected to a main circuit connecting the rotary electric machine and the inverter, Means for detecting partial discharge flowing through the rotating electric machine is provided.

In a preferred embodiment of the present invention,
The input side of the inverter or all the points of the internal DC power supply thereof and the point of the same potential as the low voltage side of the overvoltage suppressing filter and the rotating electric machine are insulated, and the input of the inverter or the inverter power supply circuit, the overvoltage suppressing filter and the rotating electric machine. Shut off the current closed circuit connecting the two, or install a magnetic circuit that links the UVW three-phase power line between the inverter power supply and the filter, or link the UVW three-phase closed circuit that connects the filter to the rotating electrical machine core. Install a magnetic circuit.

First, in the series circuit of the capacitor and the resistor of the filter, the low voltage side of the capacitor or the resistor is connected to a point having the same potential as the rotating electric machine core, and the voltage generated by the resistor is cut off on the low frequency side. It has a high pass filter or a band pass filter whose frequency (3 dB gain reduction frequency) is 1 MHz or more, preferably between 10 and 100 MHz, and has a frequency band (3 dB gain reduction frequency bandwidth) of at least 1 to 100 MHz, preferably DC
It is input to the partial discharge measuring means having a voltage measuring device of ˜1 GHz or more, and the partial discharge current or the electric charge amount is measured.

Second, in the series circuit of the filter capacitor and resistor, the low voltage side of the capacitor or resistor is
Connected to a point of the same electric potential as the rotating electrical machine core, in parallel with the resistance of the filter, a cutoff frequency with the resistance is 1 to 10 MHz, and a capacitor having a capacitance smaller than that of the filter is connected, The voltage generated in the parallel circuit of the resistor and the capacitor is input to the partial discharge measuring means, and the partial discharge charge amount is measured.

Thirdly, in the series circuit of the capacitor and the resistor in the LCR and CR filters, the low voltage side of the capacitor or the resistor is connected to the point where the low voltage side of the capacitor in the LC filter is at the same potential as the rotating electric machine core, and the rotation is performed. A current detecting means for detecting a partial discharge current is installed in a path from the lead wire of the electric machine to a point having the same potential as the rotating electric machine core through the capacitor and the resistor of the filter, and the output of the current detecting means is a partial discharge measuring means. And the partial discharge current or the charge amount is measured by the measuring means.

In the above, the low voltage side of the filter is connected to the point having the same potential as the rotating electric machine core. However, when determining the polarity of the partial discharge current, the object can be achieved without connecting at least the low-voltage side of the filter to a point having the same potential as the rotating electrical machine core. That is, in an overvoltage suppression filter in which the low-voltage side is insulated from the rotating electric machine core, the current flowing through the path from the rotating electric machine outlet to the filter is detected by the voltage generated in the partial discharge current detection means or the resistance, and the current detection means or the resistance is detected. When the polarity of the detection signal is different from that of the other two phases, the partial discharge is measured by the means for discriminating this from the partial discharge of the own phase.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. The main circuit of the inverter-driven rotary electric machine system of the present invention includes an input power supply 12, an inverter power supply 14, and a cable 1.
5 and the rotary electric machine 16.

In the first embodiment of the present invention, the inverter power source 1
The input of 4 is connected to the power supply 12 via the isolation transformer 13. The high voltage and low voltage conductors of the internal DC power source of the inverter power source 14 are, for example, ceramics, insulators such as epoxy, polyester, epoxy block, spacer materials such as FRP, film materials such as polyimide, polyester, polyethylene, vinyl chloride, polyethylene. It is insulated from the ground potential which is the same potential as the core of the rotary electric machine 16 by a cable insulating material such as silicone, fluororesin or the like.

An overvoltage suppressing filter 2 is connected to a connecting portion between the cable 15 and the rotary electric machine 16, and the filter 2 has a capacitor 4 on the rotary electric machine side of the inductance 3.
A series circuit of a resistor 5 and a resistor 5 is provided for each phase and connected in a Y shape. Further, the resistor 5 of the filter 2 is arranged on the low voltage side of the capacitor 4, and the low voltage side of the resistor 5 is connected to the same ground potential as the rotating electrical machine core.

The generated voltage of the resistor 5 is the same as that of the resistance burnout detection device 6
Is input to the partial discharge measuring device 7 via. Here, the resistance burnout detection device 6 is formed by the undervoltage / overvoltage detection relay 8 and when the resistance is deteriorated and burned out, the resistance value is lowered and the voltage is lowered, or the resistance burnout overvoltage occurs. To detect. In the partial discharge measuring device 7, after the inverter noise is removed from the voltage generated by the resistor 5 by the high-pass filter 9 whose cutoff frequency is variable between 1 and 100 MHz, the band is DC to 1 GHz and an attenuator with a 100 MHz band limiting function. The magnitude of the voltage is adjusted by 10, and the partial discharge signal is measured by the voltage measuring device 11 in the band DC to 1 GHz.

FIG. 2 shows a voltage waveform 21 and a partial discharge current waveform 22 at the rotary electric machine end of the inverter-driven rotary electric machine system of the first embodiment. In the figure, the U-phase waveform is shown.
After the overvoltage suppression / partial discharge measurement device of Example 1, the voltage waveform 21 is a rectangular wave, and the overvoltage is suppressed. In the partial discharge current waveform 22, the inverter surge noise is removed and only the partial discharge pulse 23 is detected.

FIG. 3 shows partial discharge current waveforms of each phase when partial discharge occurs in the U phase. In the inverter-driven rotary electric machine system of the first embodiment, the V phase (32) and the W phase (3
No signal is recognized in 3), and partial discharge is detected only in the U phase (31). The partial discharge detection sensitivity is shown in Table 1.
As shown in, it is the same as the conventional partial discharge measuring device.

[0022]

[Table 1] As described above, according to the first embodiment of the present invention, in the inverter-driven rotating electrical machine system, suppression of overvoltage and measurement of partial discharge can be realized at the same time.

In the first embodiment described above, the partial discharge current closed circuit connecting the rotary electric machine and the filter can be formed by connecting the low voltage side of the overvoltage suppressing filter 2 to a point having the same potential as the rotary electric machine core. Therefore, the partial discharge can be measured using the overvoltage suppressing filter 2. Further, in particular, since the overvoltage suppressing filter is installed for each phase, it is possible to form a partial discharge current closed circuit for each phase and prevent mixing of partial discharge signals of other phases. Furthermore, in the first embodiment, in particular, since the resistor 5 of the overvoltage suppressing filter 2 is arranged on the low voltage side and one end thereof is grounded, the voltage of the resistor 5 can be easily measured.

By the way, conventionally, when the low voltage side of the overvoltage suppressing filter 2 is connected to the ground potential, the zero-phase current and the loss increase, so that the partial discharge cannot be measured using the overvoltage suppressing filter. However, Example 1
In this, the input of the inverter power supply and the internal DC power supply are insulated from the low-voltage side of the rotating electric machine core and the overvoltage suppressing filter, and the current closed circuit connecting the inverter power supply, the overvoltage suppressing filter and the rotating electric machine is cut off. Therefore, even if the overvoltage suppressing filter is used, the zero-phase current and the loss can be suppressed and the partial discharge can be measured.

The capacitance of the capacitor used in the overvoltage suppression filter is generally 0.01 to 10 μF, which is sufficiently larger than the capacitance of about 1000 pF of the coupling capacitor of the conventional partial discharge measuring instrument. . Therefore, when measuring partial discharge with an overvoltage suppression filter, is it equivalent to the conventional one?
Further partial discharge detection sensitivity can be realized.

On the other hand, when partial discharge measurement is performed using an overvoltage filter, the inverter surge noise directly enters the partial discharge measuring device 7, so that it is difficult to distinguish between noise and partial discharge. However, in the first embodiment, since the partial discharge measuring device 7 is designed based on the following partial discharge and noise characteristics, noise can be suppressed and partial discharge can be measured.

FIG. 4 shows an FFT of inverter surge noise.
The spectrum is shown. As the inverter, an inverter 41 having a short surge wave crest length and a long inverter 42 are used from the IGBT inverters which have been widely used in recent years. The wavefront length of each is 0.1 and 1 μs. In any of the inverters, the signal strength of the inverter surge noise decreases as the frequency becomes higher. Further, the signal strengths are remarkably attenuated at 10 and 1 MHz or higher, respectively. Therefore, in order to measure the partial discharge of the inverter-driven rotating electric machine, it is desirable that the cutoff frequency on the low frequency side of the high-pass filter or the band-pass filter is 1 MHz or higher, and particularly 10 MHz or higher for the inverter 41 having a short wave front length.

FIG. 5 shows a partial discharge current waveform 51 of the rotating electric machine.
And FFT spectrum 52 is shown. In the FFT spectrum 52, the signal intensity of the partial discharge current is DC to 100 MH
It attenuates rapidly to z and then gradually to 1 GHz. 1 to 100 MHz of this partial discharge current and 10
1 to 100M when extracting 0MHz to 1GHz signal
The signal 53 of Hz substantially matches the partial discharge current waveform, but the signal 54 of 100 MHz to 1 GHz has an oscillating waveform. Therefore, the main frequency band of the partial discharge signal is in the range of 1 to 100 MHz, and it is desirable that the low-pass cutoff frequency of the high-pass filter or band-pass filter of the partial discharge measuring device be 100 MHz or less. Further, the band of the attenuator of the partial discharge measuring device and the voltage measuring device is preferably at least 1 to 100 MHz, and DC to 1 GHz or more is preferable in order to faithfully measure the signal. As described above, since the partial discharge measuring device 7 is designed by examining the frequency characteristics of the inverter surge noise and the partial discharge current, it is possible to suppress the noise and measure the partial discharge.

As described above, in the first embodiment, the rotary electric machine 16 that transmits and receives electric power from the power source 12 via the inverter 14, and the overvoltage suppression filter connected to the main circuit connecting the rotary electric machine 16 and the inverter 14. In an inverter-driven rotary electric machine system including two, partial discharge measuring means 5 for measuring partial discharge using the overvoltage suppressing filter 2
~ 7 are provided. Further, this partial discharge is detected by the current detection means 5 to 7 which detects the current flowing through the overvoltage suppressing filter 2 and the rotary electric machine 16.

6 and 7 show different examples of the second embodiment of the present invention. Note that in the second and subsequent embodiments, the same symbols are used for devices that are common to the first embodiment, and description thereof is omitted.
In the second embodiment, the low voltage side of the overvoltage suppressing filter 2 and the connecting wire 61 of the rotating electric machine core are insulated from the ground potential. Although the inverter power supply side is insulated from the ground potential in the above-described first embodiment, even if the overvoltage suppressing filter 2 and the core of the rotary electric machine 16 are insulated from the ground potential, the zero-phase current is suppressed as in the first embodiment. It is possible to suppress overvoltage and measure partial discharge. In particular, as shown in FIGS. 6 and 7, when using the power source 62 in which one point of the input power source is grounded or the inverter 71 in which one point of the direct current power source is grounded, the low voltage side and the rotation of the overvoltage suppressing filter 2 are used. Since a large zero-phase current flows when the core of the electric machine 16 is grounded, it is desirable to use the inverter-driven rotating electric machine system of the second embodiment. In the second embodiment, since the low voltage side of the overvoltage suppressing filter 2 is set to the floating potential, the voltage is generated with respect to the ground potential. For this reason, it is desirable to use an optical isolator as described in Examples 10 and 11 to be described later, or a balanced-type measuring instrument such as a differential probe or a differential amplifier, before the resistance burnout detector 6. .

The third embodiment will be described with reference to FIG. In the third embodiment, in particular, the common mode coil 81 is installed on the UVW three-phase power supply line, and the inductance can be increased with respect to the zero-phase current. Therefore, the overvoltage suppression filter 2
Even if the low-voltage side of is grounded, the zero-phase current can be suppressed, overvoltage can be suppressed, and partial discharge can be measured. In FIG. 8, the coil 81
Is installed on the rotary electric machine side of the cable 15,
The installation place is not limited as long as it is between the inverter power supply 14 and the overvoltage suppression filter 2.

The fourth embodiment will be described with reference to FIG. In the fourth embodiment, in particular, the common mode coil 91 is connected to the UVW three-phase closed circuit connecting the overvoltage suppressing filter 2 to the rotary electric machine core.
The inductance can be increased for the zero-phase current flowing from the inverter power supply 14 to the ground potential via the overvoltage prevention filter 2 and the core of the rotary electric machine 16, and the inductance can be decreased for the partial discharge current flowing in the closed circuit. Therefore, even if the low-voltage side of the overvoltage suppression filter 2 is connected to the rotating electric machine core and grounded, the zero-phase current is suppressed and the overvoltage can be suppressed and the partial discharge can be measured. In the fourth embodiment, since the low voltage side of the overvoltage suppression filter has a potential with respect to the zero-phase voltage, a balanced measuring device such as an optical isolator, a differential probe, and a differential amplifier is used before the resistance burnout detecting device 6. It is desirable to do.

The fifth embodiment will be described with reference to FIG. In the fifth embodiment, the overvoltage suppressing filter 2 includes the capacitor 10
1 and a resistor 102. In the fifth embodiment, no inductance is used, but the cutoff frequency of the capacitor 101 and the resistor 102 is set lower than the frequency of the inverter surge, and the value of the resistor 102 is set to the same level as the surge impedance of the cable. Overvoltage can be prevented. That is, in the frequency range of the inverter surge, CR
Since the filter can be regarded as the resistor 62, reflection of surge voltage and occurrence of overvoltage can be prevented by impedance matching. Therefore, the inverter-driven rotary electric machine system according to the fifth embodiment can suppress the overvoltage and measure the partial discharge.

The sixth embodiment will be described with reference to FIG. In the first to fifth embodiments so far, the overvoltage suppressing filter 2 and the core of the rotating electric machine 16 are directly connected, but the low voltage side of the overvoltage suppressing filter 2 and the core of the rotating electric machine 16 may be connected via a resistor. . That is, even if the low voltage side of the overvoltage suppressing filter 2 is connected to the ground potential via the resistor 111, the overvoltage suppressing and the partial discharge measurement can be performed. In particular, when the resistor 111 is inserted, of the zero-phase currents that are difficult to suppress in the first, third, and fourth embodiments, the current flowing to the ground potential via the filter can be reduced. Further, the resistance 111 is a variable resistance, and when the partial discharge measurement is not performed, the resistance value is increased to reduce the zero-phase current and loss during operation. Further, when the partial discharge is simply measured in the three-phase batch, the partial discharge can be measured by using the resistor 111.

The seventh embodiment will be described with reference to FIG. In the sixth embodiment, a resistor is installed on the filter side, and the low voltage side of the overvoltage suppressing filter 2 and the core of the rotary electric machine 16 are connected to the resistor 111.
However, the resistor 121 may be installed on the rotary electric machine 16 side. That is, even if the core of the rotary electric machine 16 is grounded by the resistor 121, overvoltage suppression and partial discharge measurement can be performed. In particular, when the resistor 121 is inserted, of the zero-phase currents that are difficult to suppress in the first, third, and fourth embodiments, the current flowing to the ground potential via the rotating electric machine core can be reduced. Further, when the resistor 121 is connected to the rotating electric machine side, the inverter surge noise and the partial discharge signal can be distinguished from the polarity of the signal. That is, comparing the polarities of the signals detected by the overvoltage suppression filter 2 and the resistor 121, as shown in Table 2, the partial discharge signal has the opposite polarity and the inverter surge noise has the same polarity.

[0036]

[Table 2] Therefore, high-frequency noise that is difficult to remove even with the partial discharge measuring apparatus 7 can be removed by determining the polarity for each pulse. In the seventh embodiment as well, the use of the variable resistor can reduce the zero-phase current and loss during operation.

The eighth embodiment will be described with reference to FIG. In the sixth and seventh embodiments, the low voltage side of the voltage prevention filter 2 and the rotating electric machine are connected via a resistor, but they may be connected by a capacitor. That is, even if the low voltage side of the overvoltage suppressing filter is connected to the ground potential via the capacitor 131 as shown in FIG. 13, overvoltage suppression and partial discharge measurement can be performed. In particular, since the impedance of the capacitor becomes smaller as the frequency becomes higher, the impedance can be made smaller for the high frequency partial discharge signal and can be made larger for the zero phase voltage of the inverter. Further, the capacitor 131 is a variable capacitor, and the capacitance is reduced when partial discharge measurement is not performed, whereby the zero-phase current and loss during operation can be reduced.

The ninth embodiment will be described with reference to FIG. In the eighth embodiment, the capacitor is installed on the filter side, and the low voltage side of the overvoltage suppressing filter and the rotating electric machine core are connected via the capacitor. However, the capacitor may be installed on the rotating electric machine side. That is, the rotating electric machine core is connected to the capacitor 14
Even if it is grounded at 1, overvoltage suppression and partial discharge measurement can be performed.
Further, as in the case of the eighth embodiment, by using the variable capacitor as the capacitor 141, it is possible to reduce the zero-phase current and the loss during operation.

The tenth embodiment will be described with reference to FIG.
In the tenth embodiment, in the series circuit of the resistor 152 of the overvoltage suppressing filter 2 and the capacitor 153, the resistor 152 is arranged on the high voltage side, and the voltage generated by the resistor 152 is converted into an optical signal by the electro-optical conversion device 154. Optical fiber 155
To transmit. After that, the optical signal is converted into an optical-electrical conversion device 156.
Is converted into an electric signal and input to the partial discharge measuring device 7 through the resistance burnout detecting device 6 to measure the partial discharge. Example 10
Then, the isolation system was used in this way. By doing so, the overvoltage suppressing filter 2
Even if the resistor 152 is arranged on the high voltage side, overvoltage suppression and partial discharge measurement can be performed. In particular, when the resistor 152 is arranged on the high voltage side, as shown in FIG. 16, one side of each phase capacitor 162 is connected and grounded in the housing, and the high voltage bushing 1 is externally provided.
It is possible to use a capacitor in which only 61 is arranged.

The eleventh embodiment will be described with reference to FIG.
In the eleventh embodiment, the voltage generated by the resistor 152 is measured by the high-voltage differential probe 171, and the partial discharge is measured.
In the same manner as above, overvoltage suppression and partial discharge measurement can be performed.

The twelfth embodiment will be described with reference to FIG.
In the twelfth embodiment, in the overvoltage suppressing filter 2, in particular, a parallel circuit 183 of a resistor and a capacitor is connected in series to the capacitor 182, and the voltage generated by the capacitor is passed through the resistance burnout detecting device 6 and the partial discharge measuring device. Input to 7. In the twelfth embodiment, the value of the resistor or the capacitor can be adjusted so that the cutoff frequency of the parallel circuit is 1 to 10 MHz. However, the capacitance of the capacitor of the parallel circuit 183 can be adjusted within the range of the filter capacitor 182 or less.
Even if the capacitor 182 is connected in parallel to the resistor of the overvoltage suppressing filter 2 as in the twelfth embodiment, overvoltage suppression and partial discharge measurement can be performed as in the first to eleventh embodiments. This is because with respect to overvoltage suppression, the parallel circuit of the twelfth embodiment can be regarded as a resistor in the frequency range of the inverter surge, and therefore the same effects as those of the first to eleventh embodiments can be obtained. On the other hand, regarding partial discharge measurement, when the above conditions are satisfied, the partial discharge current flows through the capacitors of the parallel circuit, so that a voltage proportional to the integral value of the partial discharge current is generated in the parallel circuit 183. However, if this is differentiated with respect to time, it matches the current values of the first to eleventh embodiments, so that even with the configuration of the twelfth embodiment, the partial discharge can be measured. In addition,
In particular, when comparing and examining the partial discharge charge amount during sine wave voltage operation, in Example 12, the charge amount, which is the integrated value of the partial discharge current, can be directly measured, so that the comparison can be easily performed. Further, in the twelfth embodiment, in particular, since the capacitance of the capacitor of the parallel circuit 183 is equal to or less than the capacitor 182 of the filter, the partial discharge can be measured with substantially the same detection sensitivity as the conventional one.

The thirteenth embodiment will be described with reference to FIG.
In the thirteenth embodiment, unlike the first to eleventh embodiments, the partial discharge current is measured by the current probe 191 and the amplifier 192.
In this way, overvoltage suppression and partial discharge measurement can be performed using the current probe. This is because the current can be measured with a magnetic circuit element such as a current probe without using a resistor, particularly when measuring the current. Further, in particular, since the current probe is used, the thirteenth embodiment has an advantage that the partial discharge current can be measured by disposing the current probe on the high voltage wire between the filter and the rotating electric machine as shown in FIG.

Further, in the thirteenth embodiment, as shown in FIG. 21, overvoltage suppression and partial discharge measurement can be performed even with an LC filter having no resistance. In addition to the current probe, a Rogowski coil or a high-frequency CT can be used as the current detector.

The fourteenth embodiment will be described. In all of the first to thirteenth embodiments described so far, the low voltage side of the overvoltage prevention filter 2 has to be connected to a point having the same potential as the rotating electric machine core to form a partial discharge current closed circuit for each phase. . However, in the fourteenth embodiment, by determining the polarity of the partial discharge current, the partial discharge can be measured for each phase without connecting the low-voltage side to a point having the same potential as the rotary electric machine core.

22 to 26 show a fourteenth embodiment. In the fourteenth embodiment, the partial discharge current flowing in the path from the overvoltage suppressing filter 2 of each phase to the rotating electric machine is converted into the resistance 5 (FIGS. 22 to 24) of the overvoltage suppressing filter or the current probe 1.
91 (FIGS. 25 and 26), and if necessary, input to the partial discharge measuring device 7 via the resistance burnout detecting device 6. The signal measured by the partial discharge measurement device is the polarity determination device 221,
For example, by using a logic trigger of a digital oscilloscope and comparing the signal polarities of the UVW three phases as shown in Table 3 and determining that partial discharge has occurred in a phase different in polarity from the other phases, each phase is determined. The partial discharge of can be measured.

[0046]

[Table 3] Hereinafter, the operation of the fourteenth embodiment will be described. FIG. 27 shows an equivalent circuit of the rotary electric machine. The rotating electric machine generally has a coil 27.
It can be represented by a ladder-type equivalent circuit in which an inductance 272 of No. 1, a capacitance 273 for ground insulation between a coil conductor and a rotating electric machine core, and an interlayer insulation capacitance 274 between coil winding conductors are connected. When the UVW phases of the rotating electric machine are connected by the overvoltage suppressing filter 2, for example, U
When a partial discharge occurs in the ground insulation 278 with the star mark of the phase 275, the charges accumulated in the ground insulation or the interlayer insulation capacitance of the other V phase 276 and W phase 277 are transferred to the overvoltage suppression filter 2. Through the U phase,
Currents of 279 and 280 flow in V and W. On this occasion,
As in the fourteenth embodiment, when the partial discharge current is detected between the overvoltage suppressing filter or the output of the rotating electric machine from the filter, the current polarities become opposite in the partial discharge generation phase and the other phase. Therefore, this can be used to identify the partial discharge generation phase. It should be noted that although the description has been given using the Y-shaped winding rotary electric machine in the drawing, the partial discharge generation phase can be similarly specified in the Δ-type rotary electric machine.

As described above, in the fourteenth embodiment, by discriminating the polarity of the partial discharge current, compared with the first to thirteenth embodiments,
It is easy to prevent overvoltage and measure partial discharge. Further, in particular, in the fourteenth embodiment, a Δ type overvoltage suppressing filter which cannot be used in the first to thirteenth embodiments can be used. For this reason, overvoltage suppression and partial discharge measurement can be performed using various overvoltage suppression filters that combine L, C, and R as shown in FIGS.

In the above-described inverter-driven rotary electric machine systems of Examples 1 to 14, since overvoltage can be suppressed and partial discharge can be measured, insulation deterioration can be suppressed, insulation deterioration can be diagnosed, and rotation can be performed before the rotary electric machine causes dielectric breakdown. Electric machinery or
The coil insulation can be updated. Therefore, in the inverter-driven rotary electric machine system of the present invention, unexpected failures can be reduced, and reliability can be improved as compared with the conventional inverter-driven rotary electric machine system.

Hereinafter, a comparative example using the conventional overvoltage suppressing filter and the partial discharge measuring device will be described with reference to FIGS. As shown in FIG. 28, in the comparative example, the inverter 14 is directly connected to the input power supply 13, and the output of the inverter power supply 14 is connected to the rotary electric machine 16 via the cable 15. In addition, at the connecting portion between the cable 15 and the rotary electric machine, the overvoltage suppressing filter 2 is provided on the inverter side.
81 is arranged and the conventional partial discharge measuring device 2 is provided on the rotating electric machine side.
82 are arranged. FIG. 29 shows the voltage waveform 293 at the rotary electric machine end measured by the present inverter-driven rotary electric machine system.
And an output waveform 294 of the partial discharge measuring device 282 is shown.

When the overvoltage suppressing filter 281 and the partial discharge measuring device are connected as shown in FIG. 28, the voltage waveform 293 at the rotary electric machine end is a rectangular wave, and the overvoltage due to reflection can be suppressed. However, in the partial discharge measuring instrument, not only the partial discharge signal 295 but also the inverter surge noise 29
6 is also measured, and the partial discharge cannot be measured accurately.

FIG. 30 shows the U phase (303), V phase (304), W phase (30) when partial discharge occurs in the U phase.
The partial discharge detection signal of 5) is shown for the case 301 where the overvoltage suppressing filter is connected and the case 302 where it is not connected.
When the overvoltage suppressing filter is not connected 302, the partial discharge signal is recognized only in the U phase. However, when an overvoltage suppression filter is connected 301, not only the U phase but V
A signal is also recognized in the W phase, and the partial discharge generation phase cannot be specified. In addition, the partial discharge detection sensitivity is also reduced.

[0052]

According to the present invention, the overvoltage suppression and the partial discharge measurement during the operation of the inverter can be realized by utilizing the overvoltage suppression filter, and the reliability of the inverter driving rotating electric machine system can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an inverter-driven rotating electric machine system using an LCR filter and a partial discharge measuring device according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram of a U-phase applied voltage and a partial discharge signal when the overvoltage suppressing and partial discharge measuring apparatus of the first embodiment is used.

FIG. 3 is a UVW measured by using the overvoltage suppressing and partial discharge measuring apparatus of Example 1 when partial discharge occurs in the U phase.
Phase partial discharge detection waveform diagram.

FIG. 4 is an FFT of inverter surge noise according to the first embodiment.

FIG. 5 is an FFT of the partial discharge current generated in the induction motor of the first embodiment.

FIG. 6 is a diagram of an overvoltage suppressing and partial discharge measuring device according to a second embodiment when an input of an inverter power supply is grounded.

FIG. 7 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus according to a second embodiment when the inside of the inverter power supply is grounded.

FIG. 8 is a diagram of an overvoltage suppression and partial discharge measurement device according to a third embodiment that suppresses a zero-phase current with a common mode coil.

FIG. 9 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus according to a fourth embodiment for suppressing a zero-phase current with a common mode coil.

FIG. 10 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus of Example 5, which uses a CR filter and the partial discharge measuring apparatus of the present invention.

FIG. 11 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus of Example 6 in which the low voltage side of the overvoltage suppressing filter is grounded with a resistor.

FIG. 12 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus of Example 7, in which the rotating electric machine core is grounded by a resistor.

FIG. 13 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus of Example 8 in which the low voltage side of the overvoltage suppressing filter is grounded with a capacitor.

FIG. 14 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus of Example 9 in which a rotating electric machine core is grounded by a capacitor.

FIG. 15 is a diagram of an overvoltage suppression and partial discharge measurement apparatus of Example 10 in which the voltage of a resistor arranged on the high voltage side is measured by an optical isolator.

FIG. 16 is a structural diagram of a three-phase AC capacitor having one side connected in a housing.

FIG. 17 is a diagram of an overvoltage suppression and partial discharge measurement device according to an eleventh embodiment in which the voltage of a resistor arranged on the high voltage side is measured by a high voltage differential probe.

FIG. 18 is a diagram of an overvoltage suppressing and partial discharge measuring apparatus according to a twelfth embodiment in which a capacitor is connected in parallel with a resistor of an overvoltage suppressing filter and a partial discharge is measured.

FIG. 19 is an overvoltage suppression and partial discharge measurement device diagram of the thirteenth embodiment in which a partial discharge current is detected by a current probe arranged in a path from an overvoltage suppression filter to a rotating electric machine.

FIG. 20 is a diagram showing an overvoltage suppressing and partial discharge measuring apparatus 2 of Example 13 in which a partial discharge current is detected by a current probe arranged in a path from an overvoltage suppressing filter to a rotating electric machine.

FIG. 21 is a diagram showing an overvoltage suppressing / partial discharge measuring apparatus 3 of Example 13 in which a partial discharge current is detected by a current probe arranged in a path from an overvoltage suppressing filter to a rotating electric machine.

FIG. 22 is a diagram showing Example 14 in which a partial discharge current is detected by a current probe arranged in a path from an overvoltage suppressing filter to a rotating electric machine.

FIG. 23 is a diagram showing an overvoltage suppressing and partial discharge measuring apparatus according to a fourteenth embodiment in which a partial discharge generation phase is specified based on a polarity of a partial discharge current.

FIG. 24 is a diagram showing an overvoltage suppressing and partial discharge measuring apparatus according to a fourteenth embodiment in which a partial discharge generation phase is specified based on a polarity of a partial discharge current.

FIG. 25 is a diagram showing an overvoltage suppressing and partial discharge measuring apparatus according to a fourteenth embodiment in which a partial discharge generation phase is specified based on a polarity of a partial discharge current.

FIG. 26 is a diagram showing an overvoltage suppressing and partial discharge measuring apparatus according to a fourteenth embodiment in which a partial discharge generation phase is specified based on a polarity of a partial discharge current.

FIG. 27 is an explanatory diagram of a path and a direction of a current flowing from the VW phase to the U phase when a partial discharge occurs in the U phase.

FIG. 28 is a connection diagram and a partial discharge detection waveform diagram when a conventional overvoltage prevention filter and a partial discharge measuring device are connected.

29 is a voltage waveform 283 at the rotary electric machine end measured by the inverter-driven rotary electric machine system of FIG. 28 and an output waveform 284 of the partial discharge measuring device 282.

30 is a waveform diagram showing a decrease in partial discharge detection sensitivity when the overvoltage prevention filter of FIG. 28 is connected, and mixing of partial discharge signals of other phases.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Overvoltage suppression / partial discharge measurement device, 2 ... Overvoltage suppression filter, 3 ... Inductance, 4 ... Capacitor, 5 ... Resistor, 6 ... Resistance burnout detection device, 7 ... Partial discharge measurement device, 8
... voltage drop / overvoltage detection relay, 9 ... high-pass filter, 10 ... attenuator, 11 ... voltage measuring device, 12 ... input power supply, 13 ... insulation transformer, 14 ... inverter, 15 ... cable, 16 ... rotating electric machine.

Continued front page    (72) Inventor Ryozo Takeuchi             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. F-term (reference) 2G015 AA14 CA01                 2G016 BA03 BB02 BB09 BC02 BD01                       BD02 BD08                 5H007 AA12 BB06 CC03 DC05 FA01                       FA14 HA02

Claims (12)

[Claims] 1. An inverter-driven rotary electric machine system comprising: a rotary electric machine that transmits and receives electric power from a power supply via an inverter; and an overvoltage suppressing filter connected to a main circuit connecting the rotary electric machine and the inverter. An inverter-driven rotating electrical machine system characterized in that means for measuring partial discharge using a filter is provided. 2. A rotary electric machine system comprising: a rotating electric machine that transmits and receives electric power from a power supply via an inverter; and an overvoltage suppressing filter connected to a main circuit connecting the rotating electric machine and the inverter. An inverter-driven rotary electric machine system, characterized in that means for detecting a current flowing through the rotary electric machine is provided. 3. The input of the inverter according to claim 1, wherein all the points on the input side of the inverter or the internal DC power source thereof are insulated from the points having the same potential as the overvoltage suppressing filter and the low voltage side of the rotating electric machine. Alternatively, the current closed circuit connecting the inverter power supply circuit, the overvoltage suppression filter and the rotating electric machine may be cut off, or the U between the inverter power supply and the filter may be cut off.
An inverter-driven rotating electrical machine system characterized in that a magnetic circuit interlinking a VW three-phase power supply line is installed, or a magnetic circuit interlinking a UVW three-phase closed circuit connecting a filter to a rotating electrical machine core is installed. . 4. The overvoltage suppressing filter according to claim 1 or 2, comprising a series circuit of a capacitor and a resistor, wherein the low voltage side of the capacitor or the resistor is connected to a point having the same potential as the core of the rotating electric machine. Inverter driven rotating electrical machine system featuring. 5. The inverter driven rotation according to claim 1, wherein the overvoltage suppressing filter includes a series circuit of a capacitor and a resistor, and measures a voltage generated in the resistor to measure a partial discharge. Electric system. 6. The method according to claim 1 or 2, wherein a current detecting means is provided in a closed circuit connecting the overvoltage suppressing filter and the rotary electric machine, and the current or the electric charge of the partial discharge is measured by the current detecting means. Inverter driven rotating electrical machine system. 7. The cutoff frequency (3 dB gain reduction frequency) on the low frequency side of the high-pass filter or the band-pass filter is 1 MHz or more, preferably between 10 and 100 MHz, and the frequency band according to claim 1 or 2. (3 dB gain reduction frequency bandwidth) is at least 1 to 1
An inverter driven rotating electrical machine system having a partial discharge measuring means for measuring a partial discharge current or a charge amount with a voltage measuring device of 00 MHz, preferably DC to 1 GHz or higher. 8. The inverter driven rotating electrical machine system according to claim 1, wherein the overvoltage suppressing filter includes a series circuit of a capacitor and a resistor, and a capacitor connected in parallel to the resistor. 9. The overvoltage suppressing filter according to claim 1, further comprising a series circuit of a capacitor and a resistor, a capacitor connected in parallel with the resistor is provided, and an electrostatic capacity of the capacitor is cut off from the resistor. Frequency is 1-10 MH
An inverter-driven electric rotating machine system, wherein z is set smaller than the capacitor of the overvoltage suppressing filter. 10. The inverter driven rotating electrical machine system according to claim 9, wherein the voltage generated in the parallel circuit of the resistor and the capacitor is measured to measure the partial discharge. 11. The partial discharge current flowing between the overvoltage suppressing filter and the outlet of the rotary electric machine according to claim 1 or 2, detected by a current detector or a voltage generated in a resistor,
An inverter-driven rotating electrical machine system characterized by determining a partial discharge generation phase from the polarity of the detected partial discharge current. 12. The inverter-driven rotary electric machine system according to claim 11, wherein the detected partial discharge current polarity determines that partial discharge has occurred in a phase different from the other two phases.