JP2009290938A - Inverter apparatus and method of measuring its noise - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inverter apparatus, in which the deliberation of an effective measure to counter noise and the grasp of a measure to counter noise can be made without executing an EMC test and a simple and reliably effective measure to counter noise can be taken, and a method of measuring the noise. <P>SOLUTION: The inverter apparatus includes an inverter main circuit part 4, which includes an inverter part 8 that is constituted of power semiconductor devices Q1-Q6 and converts power from DC into AC, a noise current measuring instrument 11, which measures a noise current on the output side of the inverter circuit part 4 when it has changed at least one phase of phase voltage on the outside of the inverter main circuit part 4, a noise measuring part 10, which includes at least one of noise measuring parts 12 that measure the noise voltage, and a noise measuring results output part 17, which outputs at least either the measurement result of the noise measuring part 10 or the operation results of having performed a predetermined operation, based on this measurement results. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inverter device that converts direct current to alternating current by switching of a power semiconductor element and a noise measurement method thereof.

This type of inverter device converts DC power into AC power by switching power semiconductor elements such as transistors and IGBTs (Insulated Gate Bipolar Transistors), and noise is generated with the switching operation.
Since this noise affects the malfunction of peripheral devices and the noise to wireless devices, the following countermeasures (1) to (4) are generally taken.
(1) A noise filter is built in the inverter device.
(2) Insert a noise filter into the control panel or control system.
(3) Strengthen the ground.
(4) Shield control lines and power lines.

  In addition, because distribution is restricted unless the system is below a certain level according to the EMC (Electromagnetic Compatibility) standard, an accreditation body or the like conducts an electromagnetic environment compatibility test (EMC test) of a control panel or system equipped with an inverter device. Implement and measure the noise level. When the noise level measured by conducting an EMC test is large, countermeasures against noise are necessary, and measures are taken by spending time and money.

Therefore, conventionally, an inverter main circuit unit having a converter unit that converts AC to DC power, a smoothing main circuit capacitor that smoothes DC voltage, and an inverter unit that converts DC to AC power, and this inverter main circuit A high-frequency noise measurement unit that extracts the voltage between the ground and the phase on the input side of the unit, a simple frequency analysis unit that takes in an analog voltage value obtained by measuring the high-frequency noise in the high-frequency noise measurement unit, and converts it into a voltage level in a certain frequency component; While controlling the inverter main circuit unit, the inverter control unit for inputting the value taken in by the simple frequency analysis unit, and monitoring the operating frequency and output current of the inverter device, and the like via the inverter control unit A mode that displays the value taken from the simplified frequency analyzer as a high-frequency noise level. Inverter device and a data portion has been proposed (e.g., see Patent Document 1).
JP 2006-288111 A

In the conventional example described in Patent Document 1, the noise voltage on the input side of the inverter main circuit unit can be measured and monitored, and the noise level of the control panel or system equipped with the inverter device can be easily determined. Therefore, it is possible to easily determine whether noise countermeasures are appropriate without carrying out an EMC test at an accreditation body or the like.
However, in the conventional example described in Patent Document 1, since the noise voltage on the input side of the inverter main circuit unit is measured, the load (for example, a motor) connected to the output side of the inverter device and the load The noise level varies depending on the cable connecting the inverter and the inverter, and the relationship between noise countermeasures and their effects is complex and it is not easy to determine an effective noise countermeasure method.

That is, when the load and the cable connecting the load and the inverter device change, the impedance viewed from the inverter output side changes. As the impedance changes, the noise current changes and the noise level changes. In addition, the noise components such as filters and the load and the cable connecting the load and the inverter device resonate, so that the impedance viewed from the output side of the inverter device changes greatly, and the noise level also changes at this time. There is an unsolved problem that it is not easy to predict the noise countermeasure effect.
Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and without conducting an EMC test, it is possible to study effective noise countermeasures and grasp noise countermeasures, and to simplify the process. An object of the present invention is to provide an inverter device and a noise measurement method thereof that can surely take effective noise countermeasures.

In order to achieve the above object, an inverter device according to claim 1 includes an inverter main circuit unit including an inverter unit that is configured by a power semiconductor element and converts power from DC to AC;
A noise current measuring unit for measuring a noise current on an output side of the inverter main circuit unit and a noise voltage measuring unit for measuring a noise voltage when a phase voltage of at least one phase is changed on the output side of the inverter main circuit unit A noise measuring unit having at least one of:
And a noise measurement result output unit that outputs at least one of a measurement result of the noise measurement unit and a calculation result obtained by performing a predetermined calculation based on the measurement result.

According to a second aspect of the present invention, in the inverter device according to the first aspect, the noise current measurement unit constituting the noise measurement unit is configured to measure either one of all-phase current and ground current. The noise voltage measuring unit is configured to measure a voltage between the ground and the phase.
Furthermore, the inverter device according to claim 3 is the invention according to claim 1 or 2, wherein the noise measurement result output unit outputs at least one of the measured noise current and noise voltage as a value with respect to time as it is. The frequency conversion of at least one of the measured noise current and noise voltage and outputting as a value for the frequency and the measured noise current and noise voltage are both frequency converted, and the frequency converted noise current and It is characterized in that it has at least one configuration of calculating a quotient of noise voltage, that is, impedance, calculating impedance with respect to frequency, and outputting as impedance with respect to frequency.

  Furthermore, an inverter device according to a fourth aspect includes an inverter main circuit unit including an inverter unit configured by a power semiconductor element and converting a direct current into an alternating current, and at least one phase on the output side of the inverter main circuit unit. A noise measuring unit having a noise current measuring unit for measuring a noise current on the output side of the inverter main circuit unit when the voltage is changed, and a phase voltage of at least one phase is changed on the output side of the inverter main circuit unit A noise voltage storage unit that stores a noise voltage on the output side of the inverter main circuit unit, a noise current measured by the noise current measurement unit and a noise voltage stored in the noise voltage storage unit, Noise measurement that outputs at least one of a calculation result obtained by performing a predetermined calculation based on the noise current and the noise voltage. It is characterized in that a result output unit.

Still further, in the inverter device according to claim 5, in the invention according to claim 4, the noise current measurement unit constituting the noise measurement unit measures either one of all-phase current and ground current. It is characterized by being configured.
According to a sixth aspect of the present invention, in the invention according to the fourth or fifth aspect, the noise measurement result output unit directly outputs at least one of the measured noise current and the noise voltage stored in the storage unit. Configuration for outputting as a value for time, frequency conversion of at least one of measured noise current and noise voltage stored in the storage unit, and output as a value for frequency, and measurement noise current and storage in the storage unit At least one of the configurations of performing frequency conversion on both of the generated noise voltage, calculating an impedance that is a quotient of the noise current and the noise voltage after frequency conversion, calculating an impedance for the frequency, and outputting the impedance as an impedance for the frequency It has the structure.

Furthermore, an inverter device according to a seventh aspect is the invention according to any one of the first to sixth aspects, wherein the phase voltage of at least one phase on the output side of the inverter main circuit section is changed at least once. And an inverter operation command section for giving a command to the inverter section.
Furthermore, the noise measurement method for an inverter device according to claim 8 is a noise measurement method for an inverter device including an inverter main circuit unit having an inverter unit configured by a power semiconductor element and converting a direct current into an alternating current, A noise measuring step for measuring at least one of a noise current and a noise voltage on the output side of the inverter main circuit section when the phase voltage of at least one phase is changed on the output side of the inverter main circuit section; and the noise measurement And a noise measurement result output step for outputting at least one of a measurement result of the step and a calculation result obtained by performing a predetermined calculation based on the measurement result.

  Still further, the noise measurement method for an inverter device according to claim 9 is a noise measurement method for an inverter device including an inverter main circuit unit including an inverter unit that is configured by a power semiconductor element and converts power from DC to AC. A noise current measuring step for measuring a noise current on the output side of the inverter main circuit unit when the phase voltage of at least one phase is changed on the output side of the inverter main circuit unit; and an output side of the inverter main circuit unit A noise voltage storing step for storing a noise voltage on the output side of the inverter main circuit section when the phase voltage of at least one phase is changed, and a noise current measured in the noise current measuring step and the noise voltage storing step The measurement result of the noise voltage stored in, and the noise current and noise voltage Based on is characterized in that a noise measurement result output step of outputting at least one of the calculation result of the predetermined calculation.

  According to the present invention, when at least one phase voltage is changed on the output side of the inverter main circuit unit, at least one of the noise current and noise voltage on the output side of the inverter main circuit unit is measured, and this measurement is performed. Without performing the EMC test by outputting the result as it is or frequency-converting the measurement result, calculating the impedance that is the quotient of the noise voltage and noise current that has been frequency-converted, and outputting it as the impedance with respect to the frequency, It is possible to examine effective noise countermeasures and grasp the noise countermeasure effects, and it is possible to obtain an effect that it is possible to simply and surely take effective noise countermeasures.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of the present invention.
In the figure, reference numeral 1 denotes an inverter device having an inverter main circuit unit 4 to which three-phase AC power output from an AC power supply 2 and a ground potential are supplied via an input cable 3. The three-phase AC power input by the inverter main circuit unit 4 is full-wave rectified and then converted again to three-phase AC power and supplied to a three-phase AC motor 6 as a load via an output cable 5.

The inverter main circuit unit 4 converts a full-wave rectifier circuit 7 for full-wave rectification of power using a three-phase AC input from the AC power source 2 and converts a DC power output from the full-wave rectifier circuit 7 into a three-phase AC power. The inverter unit 8 is provided.
The full-wave rectifier circuit 7 includes a series circuit in which a pair of diodes D1 and D2 are connected in series, a series circuit in which a pair of diodes D3 and D4 are connected in series, and a series circuit in which a pair of diodes D3 and D4 are connected in series. Are connected in parallel with each other and a smoothing capacitor C connected in parallel with each of the series circuits on the output side of the diode bridge circuit DB.

  The inverter unit 8 includes a U-phase arm Au in which a pair of power semiconductor switching elements Q1 and Q2 are connected in series, a V-phase arm Av in which a pair of power semiconductor switching elements Q3 and Q4 are connected in series, and a pair of power semiconductor switching. It has a configuration in which a W-phase arm Aw in which elements Q5 and Q6 are connected in series is connected in parallel. Anti-parallel diodes D11 to D16 that flow current from the emitter side to the collector side are connected between the emitters and collectors of the power semiconductor switching elements Q1 to Q6. Here, as the power semiconductor switching elements Q1 to Q6, for example, IGBTs (Insulated Gate Bipolar Transistors) are applied.

Further, the connection midpoint of power semiconductor switching elements Q1, Q2 of U phase arm Au, V phase arm Av, and W phase arm Aw, the connection midpoint of power semiconductor switching elements Q3, Q4, and the connection of power semiconductor switching elements Q5, Q6. The midpoints are respectively connected to the three-phase AC motor 6 via power cables PCu, PCv and PCw constituting the output cable 5.
A noise measuring unit 10 is disposed on the output side of the inverter main circuit unit 4. As shown in FIG. 2, the noise measuring unit 10 measures, for example, a current measuring device 11 configured by a current transformer that measures all-phase currents flowing through the power cables PCu, PCv, and PCw connected to the inverter unit 8. As shown in FIG. 3, a voltage measuring device 12 that is interposed between power cables PCu, PCv, and PCw connected to the inverter unit 8 and the ground line PCe and that measures the common mode voltage Vc is provided.

  The power semiconductor switching elements Q1 to Q6 of the inverter unit 8 are driven and controlled by an inverter control unit 15 formed of, for example, a microcomputer. This inverter control unit 15 includes an inverter operation command unit 16 that supplies and controls drive command signals to the gates of the power semiconductor switching elements Q1 to Q6, and a noise measurement unit disposed on the output side of the inverter main circuit unit 4. And a noise measurement result output unit 17 to which ten measurement results are input.

  The inverter operation command unit 16 executes the measurement inverter control process shown in FIG. This measurement inverter control process is started when the power of the inverter control unit 15 is turned on. First, in step S1, as shown in FIG. 5A, the power semiconductor switching of the inverter unit 8 is performed when the power is turned on. By turning off the elements Q1, Q3, and Q5 and turning on the power semiconductor switching elements Q2, Q4, and Q6, the U-phase voltage Vu, the V-phase voltage Vv, and the W-phase voltage Vw are respectively converted into the full-wave rectifier circuit 7. The negative side voltage is maintained.

  Next, the process proceeds to step S2, where it is determined whether or not a predetermined time has elapsed. When the predetermined time has not elapsed, the process waits until this elapses, and when the predetermined time has elapsed, the process proceeds to step S3. Then, for example, the power semiconductor switching element Q2 is turned off, and then the process proceeds to step S4 to determine whether or not a predetermined dead time Td that has been preset has elapsed. The process waits until it elapses, and when the dead time Td elapses, the process proceeds to step S5.

In step S5, a measurement start command is output to the noise measurement result output unit 17, and then the process proceeds to step S6 to control the power semiconductor switching element Q1 to the on state, as shown in FIG. The voltage Vu is inverted to the positive side voltage of the full-wave rectifier circuit 7.
Next, the process proceeds to step S7, where it is determined whether or not the current command value for the AC motor 6 has been input. When the current command value is not input, the process waits until it is input, and the current command value is input. In some cases, the process proceeds to step S8, where a motor drive control process for driving and controlling each of the power semiconductor switching elements Q1 to Q6 of the inverter unit 8 is executed based on the current command value, and then the process proceeds to step S9, where the power is turned off. It is determined whether or not the power supply is in a state. When the power supply is kept on, the process returns to step S8. When the power supply is turned off, the process is terminated.

Further, the noise measurement result output unit 17 executes a measurement result output process shown in FIG. In this measurement result output process, first, in step S11, it is determined whether or not a measurement start command output from the inverter operation command unit 16, for example, when the power is turned on, is input. Until a measurement start command is input, the process proceeds to step S12.
In step S12, the common mode current Ic and the common mode voltage Vc measured by the current measuring device 11 and the voltage measuring device 12 are read for a predetermined period, and a storage medium such as a RAM of a microcomputer constituting the inverter control unit 15 is read. When the reading of the common mode current Ic and the common mode voltage Vc for a predetermined period is completed, the process proceeds to step S13.

  In this step S13, the read common mode current Ic and common mode voltage Vc are frequency-converted by, for example, fast Fourier transform processing, and then the process proceeds to step S14, and for each required number of frequency bands set in advance. The frequency-converted common mode voltage Vc ′ is divided by the frequency-converted common mode current Ic ′ to calculate the impedance Zc in the frequency domain that is the quotient of both, and then the process proceeds to step S15, where the impedance for the calculated frequency is calculated. After the characteristic data is output as measurement result data to an external display, printer, etc., the process proceeds to step S11.

Next, the operation of the first embodiment will be described.
Now, the power source of the inverter control unit 15 is turned off, the inverter drive control process of the inverter operation command unit 16 is stopped, and the measurement result output process of the noise measurement result output unit 17 is stopped. And In this state, all of the power semiconductor switching elements Q1 to Q6 in the inverter unit 8 of the inverter main circuit unit 4 are in an OFF state, no three-phase AC is output to the AC motor 6, and the AC motor 6 is in a rotation stopped state. .

  When the power source of the inverter control unit 15 is turned on from this state, the inverter operation command unit 16 starts to execute the measurement inverter control process shown in FIG. Therefore, first, the switching elements Q1, Q3 and Q5 constituting the upper arm in the inverter part 8 of the inverter main circuit part 4 are controlled to be in the OFF state, and the switching elements Q2, Q4 and Q6 constituting the lower arm are turned on. The phase voltages Vu, Vv, and Vw of the power cables PCu, PCv, and PCw are all controlled by the full-wave rectification of the inverter main circuit unit 4 as shown in FIGS. 5 (a), (b), and (c). The negative voltage of the circuit 7 is maintained (step S1). Therefore, the normal mode voltages Vu-v, Vv-w, and Vw-u, which are interphase voltages, are all intermediate voltages as shown in FIGS. 5D, 5E, and 5F, and are detected by the voltage measuring device 12. The common mode voltage Vc to be maintained maintains the negative voltage as shown in FIG.

  Thereafter, after a predetermined time has elapsed, the power semiconductor switching element Q2 is controlled to be in an OFF state (step S3), and then when the predetermined dead time Td has elapsed, a measurement start command is output to the noise measurement result output unit 17 Then, the power semiconductor switching element Q1 is controlled to be in an ON state, and the U-phase voltage Vu is inverted to the positive voltage of the full-wave rectifier circuit 7 as shown in FIG. 5A (step S5). S6).

In this way, by inverting the U-phase voltage Vu to the positive side voltage, the normal mode voltage, which is a line voltage, can be obtained as shown in FIG. 5C. As shown in FIG. 5 (f), the interphase voltage Vw-u increases from the intermediate voltage to the positive side voltage. On the contrary, the interphase voltage Vw-u decreases from the intermediate voltage to the negative side voltage as shown in FIG. The interphase voltage Vv-w maintains an intermediate voltage as shown in FIG.
For this reason, the common mode voltage Vc detected by the voltage measuring instrument 12 increases from the negative voltage to a voltage lower than the intermediate voltage, as shown in FIG. At this time, the common mode current Ic detected by the current measuring device 11 oscillates according to the change of the common mode voltage Vc and attenuates with the passage of time.

  The common mode current Ic and the common mode voltage Vc are measured by the current measuring device 11 and the voltage measuring device 12. At this time, since the measurement start command output from the inverter operation command unit 16 is input to the noise measurement result output unit 17, the process proceeds from step S11 to step S12 in the measurement result output process of FIG. The common mode current Ic detected in step S1 and the common mode voltage Vc measured by the voltage measuring device 12 are read for a predetermined period corresponding to the time until the end of the attenuation, and the read common mode current Ic and common mode voltage Vc are read. Is stored in a storage medium such as a RAM included in the microcomputer constituting the inverter control unit 15.

  When the storage of the common mode current Ic and the common mode voltage Vc for a predetermined period is completed, the stored common mode current Ic and the common mode voltage Vc are subjected to frequency conversion by fast Fourier transform processing (step S13), and the frequency conversion is performed. The quotient obtained by dividing the common mode voltage Vc ′ by the common mode current Ic ′, that is, the impedance Zc is calculated for each frequency band obtained by dividing the common mode current Ic ′ and the common mode voltage Vc ′ into a predetermined number. Zc is stored in a storage medium such as the RAM described above.

When the calculation of the impedance Zc for each frequency band is completed, impedance characteristic data for the frequency stored in a storage medium such as a RAM is output to an external display, printer, etc. (step S15).
Since the impedance characteristic data with respect to this frequency includes a high frequency noise component, as shown by the characteristic curve L21 in FIG. 7B, the impedance characteristic data greatly decreases at 7 MHz to 10 MHz.

Thus, when the power semiconductor switching element Q1 is inverted from the off state to the on state, a noise current flows on the output of the inverter unit 8, that is, on the output side of the inverter main circuit unit 4. According to Ohm's law, this noise current decreases when the high-frequency impedance is large, and conversely increases when the high-frequency impedance is small.
And a noise current flows through each part of the inverter apparatus 1, and the noise current which flowed to the power supply 2 side is measured as a noise terminal voltage.
For this reason, when the impedance characteristic with respect to the frequency decreases in the high frequency region of 7 MHz to 10 MHz as shown by the characteristic curve L21 in FIG. 7B, the noise terminal voltage becomes as shown by the characteristic curve L11 in FIG. , It rises in the high frequency range of 7 MHz to 10 MHz.

  For this reason, the input cable 3 between the inverter main circuit unit 4 and the power source 2 is used to improve the deterioration of the impedance characteristic in the high frequency region of 7 MHz to 10 MHz based on the impedance characteristic data shown in FIG. A core that compensates for a drop in impedance characteristics of 7 MHz to 10 MHz is selected and inserted. By inserting the core into the input cable 3 in this manner, the impedance could be increased in a high frequency band of 3 MHz or higher as shown by the characteristic curve L22 in FIG. 7B. For this reason, the noise terminal voltage was also reduced in the high frequency band of 5 MHz to 25 MHz as shown by the characteristic curve L12 in FIG. 7A, and it was confirmed that the noise countermeasure effect was obtained.

  As described above, according to the above embodiment, by switching the power semiconductor switching element, the voltage rapidly changes on the output side of the inverter main circuit unit 4, and noise current is generated on the output side of the inverter main circuit unit 4. This noise current can be accurately detected by the current measuring device 11. Then, the impedance characteristic can be accurately measured based on the noise voltage on the output side of the inverter main circuit unit 4 as well as the detected noise current. At this time, only by measuring the noise current and noise voltage when the layer voltage is changed, the impedance characteristic can be measured by a simple method without taking the EMC test, and noise countermeasures can be taken.

  Incidentally, when the inverter unit 8 of the inverter main circuit unit 4 is in a normal operation state, the phase voltages Vu, Vv and Vw of the U phase, V phase and W phase output from the inverter unit 8 are as shown in FIG. 8 (a), (b) and (c), it is constantly changing in a short cycle, and in accordance with this, normal mode voltages Vu-v, Vv-w and Vw which are line voltages are correspondingly changed. As shown in FIGS. 8D, 8E, and 8F, −u also constantly changes with a short period, and the common mode voltage that is a neutral point voltage also has a short period as shown in FIG. 8G. Since it constantly changes, the noise current detected by the current measuring device 11 also changes constantly, requiring complicated calculations and failing to accurately detect the noise current.

However, according to the above-described embodiment, while any one of the power semiconductor switching elements is switched and the phase voltage of one phase is changed once, the noise current is measured by the current measuring device 11 and the voltage measurement is performed. By measuring the noise voltage with the device 12, the accurate noise current and noise voltage can be measured, and the impedance characteristics in the frequency domain can be analyzed based on these, and an effective noise countermeasure can be easily and reliably performed. Can be taken.
In the above embodiment, the case where the U-phase voltage is changed once has been described. However, the present invention is not limited to this, and the V-phase voltage or the W-phase voltage may be changed once.

  Further, as shown in FIGS. 9A, 9B, and 9C, the U-phase voltage Vu, the V-phase voltage Vv, and the W-phase voltage Vw may be changed once at the same time. Normal mode voltages Vu-v, Vv-w, and Vw-v, which are line voltages, maintain an intermediate voltage as shown in FIGS. 9D, 9E, and 9F, and are neutral point voltages. As shown in FIG. 9 (g), the common mode voltage changes from the negative side voltage to the positive side voltage beyond the intermediate voltage, and the noise current and noise voltage due to the phase voltage change can be accurately determined as in the above-described embodiment. Can be measured.

  Further, as shown in FIGS. 10A, 10B, and 10C, one phase of the U-phase voltage Vu, the V-phase voltage Vv, and the W-phase voltage Vw, for example, the U-phase voltage Vu is changed twice. In this case, the normal mode voltages Vu-v and Vw-v, which are line voltages, are changed from the intermediate voltage to the positive voltage and the negative voltage as shown in FIGS. 10 (d) and 10 (f). The normal mode voltage Vv-w maintains an intermediate voltage, and then the normal mode voltages Vu-v, Vv-w, and Vw-v are as shown in FIGS. 10D, 10E, and 10F. Return to the intermediate voltage.

In response to this, the common mode voltage, which is a neutral point voltage, also maintains the state of increasing from the negative side voltage toward the intermediate voltage as shown in FIG. 10 (g), and then returns to the negative side voltage.
For this reason, the current measuring device 11 and the voltage measuring device 12 can measure the change in the noise current and the noise voltage twice. For example, by calculating the average value of the impedance characteristics calculated based on each measured value, More accurate noise countermeasures can be taken by measuring accurate impedance characteristics.

In the above embodiment, the case where a three-phase alternating current is input from the power supply 2 has been described. However, the present invention is not limited to this. The number of output phases, the control method, and the modulation method of the inverter main circuit unit 4 during operation are not limited, and any output phase, control method, and modulation method can be applied.
Furthermore, in the said embodiment, although the case where the all-phase output current of the inverter main circuit part 4 was measured with the current measuring device 11 was demonstrated, it is not limited to this, As shown in FIG. You may make it measure the noise current which flows through the grounding line PCe connected between the circuit part 4 and the three-phase alternating current motor 6 with the current measuring device 11.

  Furthermore, in the above embodiment, when the noise measurement result output unit 17 calculates and outputs impedance characteristics in the frequency domain based on the noise current measured by the current measuring device 11 and the noise current measured by the voltage measuring device 12. However, the present invention is not limited to this, and the noise current measured by the current measuring instrument 11 and the noise voltage measured by the voltage measuring instrument 12 are either directly or only one of them is frequency-converted to obtain a measured value in the frequency domain. May be output to an external calculation unit, and the external calculation unit may calculate the impedance characteristics in the frequency domain based on the noise current and the noise voltage.

Furthermore, in the above embodiment, the case where the noise voltage measured by the voltage measuring device 12 is used has been described. However, the present invention is not limited to this, and the change in the noise voltage when the phase voltage is changed is non-volatile. The impedance characteristics may be calculated based on the stored noise voltage and the measured noise current.
Moreover, in the said embodiment, although the case where the noise measurement result output part 17 was provided in the inverter control part 15 was demonstrated, it is not limited to this, It is made to provide the independent noise measurement result output part 17 Alternatively, the current measuring device 11 and the voltage measuring device 12 may not be always connected but may be connected when measurement is necessary.

It is a block diagram which shows one Embodiment of this invention. It is a circuit diagram which shows the installation state of an electric current measuring device. It is a circuit which shows the installation state of a voltage measuring device. It is a flowchart which shows an example of the inverter control process sequence for a measurement performed in an inverter operation command part. It is a time chart which shows the voltage waveform at the time of noise measurement. It is a flowchart which shows an example of the measurement result output process procedure performed in a noise measurement result output part. It is a characteristic diagram which shows the noise terminal voltage characteristic with respect to the frequency of an inverter apparatus, and an impedance characteristic. It is a time chart which shows the voltage waveform at the time of normal control of a prior art example. It is a time chart which shows the other voltage waveform at the time of noise measurement. It is a time chart which shows the other voltage waveform at the time of noise measurement. It is a circuit diagram which shows the other installation state of an electric current measuring device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inverter apparatus, 2 ... Power supply, 3 ... Input cable, 4 ... Inverter main circuit part, 5 ... Output cable, 6 ... Three-phase alternating current motor, 7 ... Full wave rectifier circuit, 8 ... Inverter part, 10 ... Noise measuring part , 11 ... current measurement unit, 12 ... voltage measurement unit, 15 ... inverter control unit, 16 ... inverter operation command unit, 17 ... noise measurement result output unit

Claims (9)

An inverter main circuit unit having an inverter unit configured by a power semiconductor element and converting direct current into alternating current;
A noise current measuring unit for measuring a noise current on an output side of the inverter main circuit unit and a noise voltage measuring unit for measuring a noise voltage when a phase voltage of at least one phase is changed on the output side of the inverter main circuit unit A noise measuring unit having at least one of:
An inverter device comprising: a noise measurement result output unit that outputs at least one of a measurement result of the noise measurement unit and a calculation result obtained by performing a predetermined calculation based on the measurement result.   The noise current measurement unit constituting the noise measurement unit is configured to measure either one of the currents of all phases or the ground current, and the noise voltage measurement unit measures a voltage between the ground and the phase. The inverter device according to claim 1, wherein the inverter device is configured.   The noise measurement result output unit is configured to output at least one of the measured noise current and noise voltage as a value with respect to time, and frequency-convert at least one of the measured noise current and noise voltage to obtain a value with respect to the frequency. The frequency output of both the measured noise current and the noise voltage is converted, the quotient of the noise current and the noise voltage, ie, the impedance, is calculated, the impedance for the frequency is calculated, and the impedance for the frequency is calculated. The inverter device according to claim 1, wherein the inverter device has at least one configuration for outputting. An inverter main circuit unit having an inverter unit configured by a power semiconductor element and converting direct current into alternating current;
A noise measuring unit having a noise current measuring unit for measuring a noise current on the output side of the inverter main circuit unit when the phase voltage of at least one phase is changed on the output side of the inverter main circuit unit;
A noise voltage storage unit for storing a noise voltage on the output side of the inverter main circuit unit when the phase voltage of at least one phase is changed on the output side of the inverter main circuit unit;
Noise that outputs at least one of the noise current measured by the noise current measurement unit and the noise voltage stored in the noise voltage storage unit, and a calculation result obtained by performing a predetermined calculation based on the noise current and noise voltage An inverter device comprising a measurement result output unit.   5. The inverter device according to claim 4, wherein the noise current measurement unit constituting the noise measurement unit is configured to measure any one of a current of all phases and a ground current.   The noise measurement result output unit outputs at least one of the measured noise current and the noise voltage stored in the storage unit as a value with respect to time, the measured noise current and the noise stored in the storage unit Frequency conversion of at least one of the voltages and output as a value for the frequency and both of the measured noise current and the noise voltage stored in the storage unit are frequency converted, and further the frequency converted noise current 6. The inverter device according to claim 4, wherein the inverter device has at least one configuration of calculating an impedance that is a quotient of a noise voltage, calculating an impedance with respect to a frequency, and outputting the calculated impedance as an impedance with respect to the frequency.   7. An inverter operation command unit that gives a command to the inverter unit so that at least one phase voltage on the output side of the inverter main circuit unit changes at least once. The inverter device according to claim 1. A noise measurement method for an inverter device including an inverter main circuit unit having an inverter unit configured by a power semiconductor element and converting DC power to AC power,
A noise measuring step for measuring at least one of a noise current and a noise voltage on the output side of the inverter main circuit unit when the phase voltage of at least one phase is changed on the output side of the inverter main circuit unit;
A noise measurement method for an inverter device, comprising: a noise measurement result output step for outputting at least one of a measurement result of the noise measurement step and a calculation result obtained by performing a predetermined calculation based on the measurement result. A noise measurement method for an inverter device including an inverter main circuit unit having an inverter unit configured by a power semiconductor element and converting DC power to AC power,
A noise current measuring step for measuring a noise current on the output side of the inverter main circuit unit when the phase voltage of at least one phase is changed on the output side of the inverter main circuit unit;
A noise voltage storing step for storing a noise voltage on the output side of the inverter main circuit unit when the phase voltage of at least one phase is changed on the output side of the inverter main circuit unit;
At least one of the measurement result of the noise current measured in the noise current measurement step and the noise voltage stored in the noise voltage storage step and the calculation result obtained by performing a predetermined calculation based on the noise current and the noise voltage. A noise measurement method for an inverter device, comprising: a noise measurement result output step for outputting.

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