JP4640361B2 - Parallel compensation type instantaneous voltage drop power failure countermeasure device and instantaneous power failure / power failure countermeasure method, series compensation type instantaneous voltage drop countermeasure device and instantaneous power failure countermeasure method, parallel connection type AC / DC converter with independent operation function and AC / DC conversion method thereof - Google Patents

Description

  The present invention relates to a parallel-compensated instantaneous voltage drop power failure countermeasure device, a series-compensated instantaneous voltage, which disconnects a grid interconnection switch in response to an instantaneous voltage drop or a power failure, and supplies power to the load from the AC / DC converter through a load transformer. In response to a voltage drop device or an instantaneous voltage drop or a power outage, the load is disconnected from the commercial power system, and then the self-sustained operation is started, and the AC / DC converter passes through the load transformer independently from the commercial power system. The present invention relates to a parallel connection type AC / DC converter with a self-sustaining operation function for supplying power to the load.

  The conventional demagnetization suppressing means is intended to suppress the demagnetization of the transformer for the transformer generated by the DC component included in the AC voltage generated by the AC / DC converter. As a general means, demagnetization suppression is performed by estimating a direct current component from a converter current measurement value taken into a control device and correcting an AC / DC converter output voltage command value.

  FIG. 12 is a block diagram showing a configuration of a conventional parallel compensation type instantaneous voltage drop power failure countermeasure device 90. The parallel compensation instantaneous voltage drop power failure countermeasure device 90 includes an AC switch 95. One end of the AC switch 95 is connected to an external input power supply 81, and the other end is connected to a load 98 via an external load transformer 97. The parallel compensation instantaneous voltage drop power failure countermeasure device 90 includes an instrument transformer 88 connected to the input power supply 81 side of the AC switch 95 and an instrument transformer 89 connected to the load transformer 97 side of the AC switch 95. And are provided.

  The parallel compensation instantaneous voltage drop power failure countermeasure device 90 includes an AC / DC converter 96. The AC / DC converter 96 is connected to the load transformer 97 side of the AC switch 95 via the converter transformer 85 and is connected to the DC power source 87.

  The parallel compensation type instantaneous voltage drop power failure countermeasure device 90 is provided with a control circuit 92. The control circuit 92 has a load voltage control circuit 72. FIG. 13 is a block diagram for explaining the load voltage control circuit 72.

  The load voltage control circuit 72 has an effective value calculation circuit 60. The effective value calculation circuit 60 calculates the effective value of the load voltage measured by the instrument transformer 89 and supplies it to the subtracter 63. The subtractor 63 supplies the difference obtained by subtracting the effective value from the load voltage command value to the transfer function circuit 62. The transfer function circuit 62 gives a transfer function signal generated based on the difference supplied from the subtracter 63 to the adder 65. The adder 65 gives a signal obtained by adding the transfer function signal given from the transfer function circuit 62 and the load voltage command value to the multiplier 64.

  The control circuit 92 has a reference voltage generation circuit 70. The reference voltage generation circuit 70 generates a reference voltage based on the load voltage measured by the instrument transformer 88 and supplies it to the input power supply abnormality detector 71 and the load voltage control circuit 72.

The multiplier 64 of the load voltage control circuit 72 supplies a signal obtained by multiplying the signal supplied from the adder 65 by the reference voltage supplied from the reference voltage generation circuit 70 to the gate pulse generation circuit 73. The gate pulse generation circuit 73 controls the AC / DC converter 96 by the gate pulse generated based on the multiplication signal supplied from the multiplier 64. The input power supply abnormality detection unit 71 disconnects the AC switch 95 based on the load voltage measured by the instrument transformer 88 and the reference voltage supplied from the reference voltage generation circuit 70.
JP-A-5-146166 (published on June 11, 1993) Japanese Patent Laying-Open No. 2001-231269 (published on August 24, 2001 (2001.8.24)) JP 6-38547 A (published February 10, 1994)

  FIG. 14 is a waveform diagram for explaining the operation of the load voltage control circuit 72. The broken line shows the waveform when the instantaneous voltage drop does not occur, and the solid line shows the waveform when the instantaneous voltage drop occurs. During the instantaneous voltage drop / power failure compensation operation of the instantaneous voltage drop / power failure countermeasure device, there is a risk that load voltage drop / distortion may occur due to the transient bias of the load transformer 97. In the worst case, an excessive magnetizing inrush current of the load transformer 97 may exceed the overcurrent withstand capability of the instantaneous voltage drop / power failure countermeasure device, resulting in a device stoppage.

  At time t91, an instantaneous voltage drop or a power failure occurs, the commercial power supply voltage and the load voltage become zero volts, and the load transformer magnetic flux does not change. At time t92, the load voltage is supplied from the AC / DC converter 96, and the load transformer magnetic flux starts to change while being demagnetized. Next, from time t93 to time t94, the degree (absolute value) of the bias of the load transformer magnetic flux increases, and the amplitude of the load current increases (excessive magnetizing inrush current occurs).

  The conventional demagnetization suppression means is intended for steady demagnetization of the transformer 85 for the converter. For this reason, there is a problem that it cannot be applied to the transient demagnetization suppression of the load transformer 97 at the time of instantaneous voltage drop / power failure compensation operation requiring high speed.

  In addition, when the current measurement value is used as in the conventional means, there is a case where the flexibility for different load conditions is lacking and the demagnetization suppressing function cannot be fully utilized.

  Further, in order to suppress the bias magnetism of the load transformer 97 when an instantaneous voltage drop or a power failure occurs, it is necessary to respond to a sudden transient voltage fluctuation at a speed of about 1/4 cycle or less.

  In addition, since the state of transient voltage fluctuations changes each time, it is necessary to take measures to minimize the uncertainty factor.

  The present invention has been made in view of the above-described problems, and its purpose is to suppress the bias magnetism of the load transformer, to avoid a load power supply stop at the time of instantaneous voltage drop or power failure, and to reduce the load voltage. The purpose is to prevent the drop and improve the distortion of the load voltage.

  In order to solve the above-mentioned problem, the parallel compensation type instantaneous voltage drop power failure countermeasure device according to the present invention disconnects the grid interconnection switch in response to the instantaneous voltage drop or the occurrence of a power failure, and loads from the AC / DC converter connected in parallel. A parallel-compensated instantaneous voltage drop power failure countermeasure device that feeds a load through a transformer, generating a voltage correction amount that suppresses the bias magnetism of the load transformer, and controlling the AC / DC converter based on the voltage correction amount It is characterized by providing a control means.

  According to this feature, the AC / DC converter is controlled based on the voltage correction amount that suppresses the bias magnetism of the load transformer. For this reason, the bias magnetism of the load transformer fed from the AC / DC converter is suppressed, and it is possible to avoid an instantaneous voltage drop or a load feed stop when a power failure occurs, prevent a drop in the load voltage, Distortion can be improved.

  In the parallel compensation instantaneous voltage drop power failure countermeasure device according to the present invention, the control means generates the voltage correction amount based on a load voltage supplied from the AC / DC converter to the load transformer and a reference voltage. It is preferable to include transformer magnetic flux correction means.

  According to the above configuration, the voltage correction amount can be generated with a simple configuration.

  In the parallel compensation instantaneous voltage drop power failure countermeasure device according to the present invention, the load transformer magnetic flux correction means is configured to change the magnetic flux change amount corresponding to the magnetic flux change amount of the load transformer based on the load voltage and the reference voltage. It is preferable to generate a signal and generate the voltage correction amount based on the magnetic flux change amount signal.

  According to the above configuration, it is possible to reliably suppress the bias magnetism of the load transformer based on the magnetic flux change amount signal.

  In the parallel compensation instantaneous voltage drop power failure countermeasure device according to the present invention, the load transformer magnetic flux correction means includes an integration circuit that generates the magnetic flux change amount signal based on a difference between the load voltage and the reference voltage. The magnetic flux change amount signal generated by the integration circuit is preferably reset every predetermined period.

  According to the above configuration, it is possible to reset the accumulated magnetic flux variation error based on the measurement error caused by the instrument transformer and the control component, and more appropriately suppress the bias magnetism of the load transformer. it can.

  In the parallel compensation instantaneous voltage drop power failure countermeasure device according to the present invention, the load transformer magnetic flux correction means may stop the output of the voltage correction amount after a lapse of a certain time from the occurrence of the instantaneous voltage drop or the power failure. preferable.

  Due to the fact that the amount of magnetic flux change in the load transformer that occurs during instantaneous voltage drop and power failure compensation is the integrated value of the load voltage deviation and the time when this deviation occurs, forced correction of the magnetic flux change generates load voltage deviation. Therefore, after a certain period of time has elapsed since the occurrence of a momentary voltage drop or a power failure, the output of the voltage correction amount is stopped, so that the load transformer demagnetization can be suppressed without impairing the load voltage maintaining function of the device. .

  A series compensation type instantaneous voltage drop countermeasure device according to the present invention disconnects a grid interconnection switch in response to occurrence of an instantaneous voltage drop, and supplies a load from a series-connected AC / DC converter to a load through a load transformer. The voltage drop countermeasure device is characterized in that it includes a control means for generating a voltage correction amount for suppressing the bias magnetism of the load transformer and controlling the AC / DC converter based on the voltage correction amount.

  According to this feature, the AC / DC converter is controlled based on the voltage correction amount that suppresses the bias magnetism of the load transformer. For this reason, the bias magnetism of the load transformer fed from the AC / DC converter is suppressed, it is possible to avoid the load power supply stop when the instantaneous voltage drop occurs, prevent the load voltage from dropping, and reduce the load voltage distortion. Can be improved.

  A parallel-connected AC / DC converter with a self-sustaining operation function according to the present invention disconnects a load from a commercial power system in response to an instantaneous voltage drop or a power outage, and then starts a self-sustaining operation and is independent of the commercial power system. A parallel-connected AC / DC converter with a self-sustaining function that feeds power from the AC / DC converter to the load through the load transformer, generating a voltage correction amount that suppresses the bias magnetism of the load transformer, and the voltage correction amount Control means for controlling the AC / DC converter based on the above is provided.

  According to this feature, the AC / DC converter is controlled based on the voltage correction amount that suppresses the bias magnetism of the load transformer. For this reason, the bias magnetism of the load transformer fed from the AC / DC converter is suppressed, and it is possible to avoid an instantaneous voltage drop or a load feed stop when a power failure occurs, prevent a drop in the load voltage, Distortion can be improved.

  The parallel compensation type instantaneous voltage drop power failure countermeasure method according to the present invention parallels power to a load from a parallel-connected AC / DC converter through a load transformer by disconnecting the grid interconnection switch in response to the instantaneous voltage drop or the occurrence of a power failure. A compensation type instantaneous voltage drop power failure countermeasure method, characterized in that a voltage correction amount for suppressing the bias magnetism of the load transformer is generated, and the AC / DC converter is controlled based on the voltage correction amount.

  According to this feature, the AC / DC converter is controlled based on the voltage correction amount that suppresses the bias magnetism of the load transformer. For this reason, the bias magnetism of the load transformer fed from the AC / DC converter is suppressed, and it is possible to avoid an instantaneous voltage drop or a load feed stop when a power failure occurs, prevent a drop in the load voltage, Distortion can be improved.

  The series compensation instantaneous voltage drop countermeasure method according to the present invention disconnects the grid interconnection switch in response to the occurrence of the instantaneous voltage drop, and supplies power to the load from the series-connected AC / DC converter through the load transformer. A voltage drop countermeasure method is characterized in that a voltage correction amount that suppresses the bias magnetism of the load transformer is generated, and the AC / DC converter is controlled based on the voltage correction amount.

  The parallel connection type AC / DC conversion method with independent operation function according to the present invention disconnects the load from the commercial power system in response to the occurrence of an instantaneous voltage drop or a power failure, and then starts the independent operation and is independent of the commercial power system. A parallel-connected AC / DC conversion method with a self-sustaining function for supplying power to the load from the AC / DC converter through the load transformer, generating a voltage correction amount that suppresses the bias magnetism of the load transformer, and the voltage correction amount The AC / DC converter is controlled based on the above.

  As described above, the parallel compensation type instantaneous voltage drop power failure countermeasure device according to the present invention generates a voltage correction amount for suppressing the bias magnetism of the load transformer, and controls the AC / DC converter based on the voltage correction amount. Control means to suppress the demagnetization of the load transformer fed from the AC / DC converter, avoiding an instantaneous voltage drop or stoppage of the load feed when a power failure occurs, and reducing the load voltage It is possible to prevent and improve the distortion of the load voltage.

  As described above, the series compensation type instantaneous voltage drop countermeasure device according to the present invention generates a voltage correction amount for suppressing the bias magnetism of the load transformer, and controls the AC / DC converter based on the voltage correction amount. Because it is equipped with a control means, the bias magnetism of the load transformer fed from the AC / DC converter is suppressed, it is possible to avoid a load feed stop when an instantaneous voltage drop occurs, prevent a load voltage drop, There is an effect that distortion of the load voltage can be improved.

  As described above, the parallel-connected AC / DC converter with a self-sustaining operation according to the present invention generates a voltage correction amount that suppresses the bias magnetism of the load transformer, and uses the AC / DC converter based on the voltage correction amount. Since the control means to control is provided, the bias magnetism of the load transformer fed from the AC / DC converter is suppressed, and it is possible to avoid the momentary voltage drop or the stoppage of the load feed in the event of a power failure. And the distortion of the load voltage can be improved.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 11 as follows.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a parallel compensation instantaneous voltage drop power failure countermeasure device 1a according to the first embodiment. The parallel compensation instantaneous voltage drop power failure countermeasure device 1 a includes an AC switch 5. One end of the AC switch 5 is connected to an external input power supply 11, and the other end is connected to a load 8 via an external load transformer 7. The specification of the AC switch 5 varies depending on the application, and a high-speed cutoff switch is used in FIG. 1 or FIG. On the other hand, in FIG. 11 described later, a general circuit breaker 9 is used instead of the AC switch 5.

  The AC / DC converter has the same configuration in FIG. 1 and FIG. 11, but only in FIG. In FIG. 1 and FIG. 11, the converter transformer 15 is connected in parallel between the AC switch 5 (or the circuit breaker 9) and the load transformer 7. In FIG. 10, the AC switch 5 is connected in parallel, and the input power supply 11 is connected in series.

  The parallel compensation type instantaneous voltage drop power failure countermeasure device 1a includes an instrument transformer 18 connected to the input power source 11 side of the AC switch 5 and an instrument transformer 19 connected to the load transformer 7 side of the AC switch 5. And are provided.

  The parallel compensation instantaneous voltage drop power failure countermeasure device 1 a includes an AC / DC converter 6. The AC / DC converter 6 is connected to the load transformer 7 side of the AC switch 5 through the converter transformer 15 and is connected to the DC power source 17.

  A control circuit 2 is provided in the parallel compensation instantaneous voltage drop power failure countermeasure device 1a. The control circuit 2 includes a load voltage control circuit 22 and a load transformer magnetic flux correction circuit 3. FIG. 2 is a block diagram for explaining the load voltage control circuit 22 and the load transformer magnetic flux correction circuit 3.

  The load voltage control circuit 22 has an effective value calculation circuit 30. The effective value calculation circuit 30 calculates the effective value of the load voltage measured by the instrument transformer 19 and supplies it to the subtractor 33. The subtractor 33 supplies the difference obtained by subtracting the effective value from the load voltage command value to the transfer function circuit 32. The transfer function circuit 32 gives the load voltage amplitude correction amount generated based on the difference supplied from the subtractor 33 to the adder 35. The adder 35 provides the multiplier 34 with a converter output voltage amplitude command value obtained by adding the load voltage amplitude correction amount and the load voltage command value given from the transfer function circuit 32.

  The control circuit 2 has a reference voltage generation circuit 20. The reference voltage generation circuit 20 generates a reference AC voltage based on the load voltage measured by the instrument transformer 18 and supplies it to the input power supply abnormality detection unit 21, the load voltage control circuit 22, and the load transformer magnetic flux correction circuit 3. Supply.

  The multiplier 34 of the load voltage control circuit 22 adds the converter output voltage command value obtained by multiplying the converter output voltage amplitude command value given from the adder 35 and the reference voltage supplied from the reference voltage generation circuit 20. Supply to the vessel 25.

  The load transformer magnetic flux correction circuit 3 has a subtractor 26. The subtractor 26 supplies the integrating circuit 4 with a load voltage deviation obtained by subtracting the reference AC voltage generated by the reference voltage generating circuit 20 from the load voltage of the load 8 obtained from the instrument transformer 19. Strictly speaking, the reference AC voltage generated by the reference voltage generation circuit 20 is a reference voltage with respect to the voltage of the input power supply 11, but the voltage drop of the AC switch 5 and the apparatus internal circuit shown in FIG. 1 can be ignored and is equivalent. . The control processing unit can be compressed by sharing the reference AC voltage generated by the reference voltage generation circuit 20 with the input power supply abnormality detection unit 21.

  The integration circuit 4 integrates the load voltage deviation supplied from the subtractor 26 to calculate the amount of change in magnetic flux of the load transformer 7 and supplies it to the line / phase conversion circuit 27. The line / phase conversion circuit 27 performs line / phase conversion on the amount of magnetic flux change supplied from the integration circuit 4 and supplies it to the subtractor 28. The subtracter 28 supplies the transfer function circuit 29 with a deviation obtained by subtracting the magnetic flux change amount supplied from the line / phase conversion circuit 27 from the magnetic flux change command value. The transfer function circuit 29 generates a voltage correction amount that suppresses the demagnetization of the load transformer 7 by the PI control transfer function, and supplies the voltage correction amount to the adder 25.

  The adder 25 supplies the gate pulse generation circuit 23 with a signal obtained by adding the converter output voltage command value supplied from the multiplier 34 and the voltage correction amount supplied from the transfer function circuit 29. The gate pulse generation circuit 23 calculates a corresponding gate pulse signal based on the signal supplied from the adder 25 and outputs it to the AC / DC converter 6. PWM (Pulse Width Modulation) is normally used in an instantaneous voltage drop / power failure countermeasure device or an instantaneous voltage drop countermeasure device that requires high speed.

  The input power supply abnormality detector 21 disconnects the AC switch 5 based on the load voltage measured by the instrument transformer 18 and the reference voltage supplied from the reference voltage generation circuit 20.

  By integrating the load voltage deviation by the integrating circuit 4, the amount of change in magnetic flux of the load transformer 7 can be calculated. Setting the amount of change in magnetic flux to zero as much as possible suppresses the bias magnetism of the load transformer 7. Actually, the magnetizing inrush current of the load transformer 7 may be equal to or less than the current value at which the apparatus stops and does not fall within the load voltage drop / distortion range.

  Since the magnetic flux change amount is a value for the circuit to which the load transformer 7 is connected, the magnetic flux change amount corresponding to the AC / DC converter 6 that suppresses the demagnetization of the load transformer 7 is calculated by the converter transformer 15. Convert to a value corresponding to the transformation ratio and connection method.

  In the present embodiment, a value obtained by subtracting the magnetic flux variation corresponding to the AC / DC converter 6 from the magnetic flux variation command value (that is, zero) is given to the transfer function circuit 29. The output from the transfer function circuit 29 becomes the converter output voltage correction amount that is the output of the load transformer magnetic flux correction circuit 3. The transfer function circuit 29 can be configured arbitrarily according to the required specifications. Specific examples include a configuration that executes proportional / integral control and a configuration that executes proportional control.

  The converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3 and the converter output AC voltage command value generated by the load voltage control circuit 22 are synthesized by an adder 25, and the gate pulse generation circuit 23 is combined. Given to. The gate pulse generation circuit 23 calculates a corresponding gate pulse signal and outputs it to the AC / DC converter 6. By these, it is possible to suppress the bias magnetism of the load transformer.

  FIG. 3 is a waveform diagram for explaining the operation of the load transformer magnetic flux correction circuit 3. The broken line in the commercial power supply voltage and the load voltage shows the waveform when no instantaneous voltage drop occurs, the broken line in the load transformer magnetic flux and the load current shows the waveform in the configuration of the prior art of FIG. 14, and the solid line is The waveform by the structure which provided the load transformer magnetic flux correction circuit 3 which concerns on this Embodiment is shown. When an instantaneous voltage drop or a power failure occurs, the input power supply abnormality detection circuit 21 disconnects the AC switch 5, and a load current is supplied from the AC / DC converter 6 to the load 8 via the converter transformer 15 and the load transformer 7. Is done. In the present embodiment, the load transformer magnetic flux correction circuit 3 generates a converter output voltage correction amount that suppresses the demagnetization of the load transformer 7, and the AC / DC converter 6 is connected based on the converter output voltage correction amount. Control. For this reason, the bias magnetism of the load transformer is suppressed, the load power supply stoppage at the time of occurrence of instantaneous voltage drop or power failure is avoided, load voltage drop is prevented, and load voltage distortion is improved.

  At time t1, an instantaneous voltage drop or power failure occurs, the commercial power supply voltage and the load voltage become zero volts, and the load transformer magnetic flux does not change. From time t2, the AC / DC converter 6 is controlled based on the converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3, the load voltage is supplied, and the load transformer magnetic flux starts to change. As shown in FIG. 3, based on the converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3, the load voltage changes transiently, and the load transformer magnetic flux indicates the prior art. It changes in a manner in which the demagnetization is reduced as compared with the broken line. For this reason, the load current does not increase in amplitude (excessive excitation inrush current) due to the configuration of the prior art indicated by the broken line.

  As described above, in the present embodiment, a reference voltage synchronized with the load voltage taken into the control circuit 2 is generated by the reference voltage generation circuit 20, and the load voltage is integrated by integrating the difference between the transiently changing load voltage and the reference voltage. The amount of magnetic flux change of the transformer 7 is estimated. Further, the transfer function circuit 29 outputs a converter output voltage correction amount that makes the magnetic flux change amount zero from the estimated magnetic flux change amount. The magnetic flux change amount is an integral value of the voltage change amount and time, and since the time is a positive value, the sign of the converter output voltage correction amount is different from the sign of the magnetic flux change amount estimated value. The transfer function circuit 29 can be configured by a circuit corresponding to a PI control transfer function.

  FIG. 4 is a circuit diagram for explaining another load transformer magnetic flux correction circuit 3a, and FIG. 5 is a waveform diagram for explaining the operation thereof. The broken line shows the waveform in the configuration of the prior art of FIG. 14, and the solid line shows the waveform by the configuration provided with the load transformer magnetic flux correction circuit 3a according to the present embodiment. The same components as those of the load transformer magnetic flux correction circuit 3 described above with reference to FIG. Therefore, detailed description of these components is omitted. The difference from the load transformer magnetic flux correction circuit 3 is that a correction voltage calculation unit 37 is provided in place of the transfer function circuit 29 as means for calculating the converter output voltage correction amount.

  By giving a magnetic flux change amount corresponding to the AC / DC converter 6 as an input to the correction voltage calculation unit 37, the amplitude and polarity of the converter output voltage correction amount necessary for suppressing the demagnetization of the load transformer 7 are obtained. The correction voltage calculation characteristics can be arbitrarily configured according to the required specifications. As a specific example, there are those having the following characteristics with respect to the amount of change in magnetic flux at the time when an instantaneous voltage drop or power failure is detected.

Polarity: Reverse polarity of magnetic flux change amount Amplitude: Magnetic flux change amount / Amplitude value of (time corresponding to 1/4 cycle) When an instantaneous voltage drop or power failure occurs, the input power supply abnormality detection circuit 21 disconnects the AC switch 5. Then, a load current is supplied from the AC / DC converter 6 to the load 8 via the converter transformer 15 and the load transformer 7. In the present embodiment, the load transformer magnetic flux correction circuit 3a provided with the correction voltage calculation unit 37 generates a converter output voltage correction amount that suppresses the bias magnetism of the load transformer 7, and this converter output voltage correction amount. The AC / DC converter 6 is controlled based on the above. For this reason, the bias magnetism of the load transformer 7 is suppressed, the load power supply stoppage at the time of occurrence of an instantaneous voltage drop or a power failure is avoided, the load voltage is prevented from being lowered, and the distortion of the load voltage is improved.

  At time t3, an instantaneous voltage drop or power failure occurs, the commercial power supply voltage and the load voltage become zero volts, and the load transformer magnetic flux does not change. Then, from time t4, the AC / DC converter 6 is controlled based on the converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3a, the load voltage is supplied, and the load transformer magnetic flux starts to change. As shown in FIG. 5, the load voltage changes transiently based on the converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3a, and the load transformer magnetic flux indicates the prior art. It changes in a manner in which the demagnetization is reduced as compared with the broken line. For this reason, the load current does not increase in amplitude (excessive excitation inrush current) due to the configuration of the prior art indicated by the broken line.

  FIG. 6 is a circuit diagram for explaining still another load transformer magnetic flux correction circuit 3b, and FIG. 7 is a waveform diagram for explaining the operation thereof. The same components as those of the load transformer magnetic flux correction circuit 3a described above with reference to FIG. 4 are denoted by the same reference numerals. Therefore, detailed description of these components is omitted. The difference from the load transformer magnetic flux correction circuit 3a is that a reset signal is supplied to the integration circuit 4 from the reference voltage generation circuit 20a.

  In actual equipment, measurement errors occur due to variations in instrument transformers 18 and 19 and parts of the control device, and therefore errors may accumulate in the amount of magnetic flux change that is the output of the integration circuit 4. Therefore, there is a possibility that the converter output voltage correction amount at the time of improper instantaneous voltage drop / power failure compensation operation is output and the load transformer demagnetization suppression does not function normally.

  As the above countermeasure, it can be solved by initializing (resetting) the integrating circuit 4 at regular intervals during normal operation. In practice, the error in the calculated value of the magnetic flux change amount of the load transformer 7 during normal operation is relatively small, and in order to distinguish it from the magnetic flux change amount at the time of transient that needs to suppress the demagnetization, every commercial frequency cycle. Perform initialization.

  The integrating circuit 4 is reset at the timing of zero crossing when the load voltage before the instantaneous voltage drop or power failure occurs shifts from minus to plus.

  At time t5, an instantaneous voltage drop or power failure occurs, the commercial power supply voltage and the load voltage become zero volts, and the load transformer magnetic flux does not change. From time t6, the AC / DC converter 6 is controlled based on the converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3b, the load voltage is supplied, and the load transformer magnetic flux starts to change. As shown in FIG. 7, based on the converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3b, the load voltage changes so as to rise transiently, and the load transformer magnetic flux reduces the demagnetization. Vary in the manner described. For this reason, the amplitude increase (excessive excitation inrush current) indicated by the broken line does not occur in the load current.

  By these, it is possible to prevent control failure due to measurement / calculation error of load transformer bias magnetism suppression.

  FIG. 8 is a circuit diagram for explaining still another load transformer magnetic flux correction circuit 3c, and FIG. 9 is a waveform diagram for explaining the operation thereof. The broken line graph in FIG. 9 is the same as the solid line graph in FIG. The same components as those of the load transformer magnetic flux correction circuit 3a described above with reference to FIG. 4 are denoted by the same reference numerals. Therefore, detailed description of these components is omitted. The difference from the load transformer magnetic flux correction circuit 3a is that a pulse output unit 36 is provided at the output stage of the load transformer magnetic flux correction circuit 3c.

  The configuration of the load transformer magnetic flux correction circuits 3, 3 a, and 3 b shown in FIGS. 2, 4, and 6 is an indispensable means for suppressing the demagnetization of the load transformer 7, but the instantaneous voltage drop / power failure countermeasure device However, there is a problem that the load voltage maintaining function originally required for the instantaneous voltage drop countermeasure device or the parallel connection type AC / DC converter with a self-sustaining operation function may be impaired. Due to the fact that the amount of magnetic flux change of the load transformer 7 that occurs during the instantaneous voltage drop / power failure compensation operation is the integral value of the load voltage deviation and the time when this deviation occurred, the forced correction of the amount of magnetic flux change is Generate a deviation.

  In other words, load transformer bias suppression is required only for a short period of time when overcurrent, load voltage drop, and distortion occur due to bias, and is necessary when the amount of change in magnetic flux of the load transformer 7 becomes small enough to be ignored. That is not.

  By providing the pulse output unit 36 at the output stage of the load transformer magnetic flux correction circuit 3c, the load transformer magnetic flux shown in FIG. 2, FIG. 4 and FIG. 6 only during a preset period at the time of instantaneous voltage drop / power failure compensation. A converter output voltage correction amount equivalent to that of the correction circuits 3, 3a, and 3b is output, and when the set time is exceeded, the output of the converter output voltage correction amount is stopped.

  At time t7, an instantaneous voltage drop or power failure occurs, the commercial power supply voltage and the load voltage become zero volts, and the load transformer magnetic flux does not change. From time t8, the AC / DC converter 6 is controlled based on the converter output voltage correction amount generated by the load transformer magnetic flux correction circuit 3c, the load voltage is supplied, and the load transformer magnetic flux starts to change. The output of the converter output voltage correction amount is stopped after 1/2 cycle from time t7.

  By these, it is possible to realize load transformer demagnetization suppression without impairing the load voltage maintaining function of the device.

(Embodiment 2)
FIG. 10 is a block diagram showing the configuration of the series compensation instantaneous voltage drop countermeasure device 1b according to the second embodiment. The same components as those of the parallel compensation instantaneous voltage drop power failure countermeasure device 1a described above with reference to FIG. 1 are denoted by the same reference numerals. Detailed description of these components will be omitted. The difference from the parallel compensation type instantaneous voltage drop power failure countermeasure device 1a is that the converter transformer 15 is connected to both the input power source 11 side and the load transformer 7 side of the AC switch 5 and the series compensation type instantaneous voltage drop countermeasure. It is a device.

  Also in the series compensation type instantaneous voltage drop countermeasure device 1b configured as described above, the load transformer magnetic flux correction circuits 3 · 3a · 3b · 3c and the adder 25 are provided in the control circuit 2 so as to be described in the first embodiment. The same effect as that obtained can be obtained.

(Embodiment 3)
FIG. 11 is a block diagram illustrating a configuration of a parallel connection type AC / DC converter 1c with a self-sustaining operation function according to the third embodiment. The same components as those of the parallel compensation instantaneous voltage drop power failure countermeasure device 1a described above with reference to FIG. 1 are denoted by the same reference numerals. Detailed description of these components will be omitted. The difference from the parallel compensation type instantaneous voltage drop power failure countermeasure device 1a is that a general-purpose circuit breaker 9 is provided instead of the AC switch 5 to configure a parallel connection type AC / DC converter with a self-sustaining operation function.

  By adding the load transformer magnetic flux correction circuits 3, 3a, 3b, 3c and the adder 25 to the control circuit of the conventional parallel connection type AC / DC converter with a self-sustaining operation function, the load transformer bias shown in the first embodiment is added. A magnetic suppression function can be provided, and the same effects as those described in Embodiment 1 can be obtained.

  In this case, when an instantaneous voltage drop or a power failure occurs, the circuit breaker 9 is opened, and the voltage start-up time when starting a self-sustaining operation is shortened thereafter.

  In FIGS. 3, 5, 7, and 9 in the first to third embodiments, an example is shown in which an instantaneous voltage drop occurs and the commercial power supply voltage and the load voltage become zero volts. It is not limited. The present invention can also be applied to a case where the commercial power supply voltage and the load voltage do not decrease 100% but partially decrease due to an instantaneous voltage drop or a power failure.

  As described above, according to the first to third embodiments, the load transformer has a larger capacity than the instantaneous voltage drop / power failure countermeasure device, the instantaneous voltage drop countermeasure device, and the parallel-connected AC / DC converter with a self-sustaining operation function. However, it is possible to prevent an overcurrent stop due to load transformer biasing that can occur during operation switching. Moreover, load voltage drop and distortion caused by load transformer bias can be reduced. In addition, control failure due to measurement / calculation errors can be prevented, and the above-described effects can be obtained without impairing the load voltage maintaining function, which is the most important function of the apparatus.

  Furthermore, since the present invention uses load voltage measurement values instead of current measurement values, the present invention can cope with various load conditions such as load capacity, load power factor, and harmonic distortion.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention relates to a parallel compensated instantaneous voltage drop power failure countermeasure device and its instantaneous power failure / power failure countermeasure method, a series compensated instantaneous voltage drop countermeasure device and its instantaneous power failure countermeasure method, and a parallel-connected AC / DC converter with a self-sustaining operation function, and It can be applied to the AC / DC conversion method.

1 is a block diagram illustrating a configuration of a parallel compensation instantaneous voltage drop power failure countermeasure device according to Embodiment 1. FIG. It is a circuit diagram for demonstrating the load transformer magnetic flux correction circuit provided in the said instantaneous voltage drop power failure countermeasure device. It is a wave form diagram for demonstrating operation | movement of the said load transformer magnetic flux correction circuit. It is a circuit diagram for demonstrating the other load transformer magnetic flux correction circuit provided in the said instantaneous voltage drop power failure countermeasure device. It is a wave form diagram for demonstrating operation | movement of the said other load transformer magnetic flux correction circuit. It is a circuit diagram for demonstrating the further another load transformer magnetic flux correction circuit provided in the said instantaneous voltage drop power failure countermeasure device. It is a wave form diagram for demonstrating operation | movement of the said further another load transformer magnetic flux correction circuit. It is a circuit diagram for demonstrating the further another load transformer magnetic flux correction circuit provided in the said instantaneous voltage drop power failure countermeasure device. It is a wave form diagram for demonstrating operation | movement of the said further another load transformer magnetic flux correction circuit. 5 is a block diagram showing a configuration of a series compensation type instantaneous voltage drop countermeasure device according to Embodiment 2. FIG. It is a block diagram which shows the structure of the parallel connection type | mold AC / DC converter with an independent operation function which concerns on Embodiment 3. It is a block diagram which shows the structure of the conventional parallel compensation type | mold instantaneous voltage drop power failure countermeasure device. It is a block diagram for demonstrating the load voltage control circuit provided in the said instantaneous voltage drop power failure countermeasure device. It is a wave form diagram for demonstrating operation | movement of the said load voltage control circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Parallel compensation type instantaneous voltage drop power failure countermeasure device 1b Series compensation type instantaneous voltage drop countermeasure device 1c Parallel connection type AC / DC converter with independent operation function 2 Control circuit
3. Load transformer magnetic flux correction circuit (load transformer magnetic flux correction means)
4 Integration circuit 5 AC switch (system interconnection switch)
6 AC / DC converter 7 Load transformer 8 Load 9 Circuit breaker 11 Input power supply 15 Transformer for converter 17 DC power supply

Claims (7)

A grid interconnection switch is provided between an external input power source and an external load, and an external load transformer is connected in series between the grid interconnection switch and the load, and the grid interconnection switch and the load transformer An AC / DC converter connected in parallel with the converter, disconnecting the grid connection switch in response to an instantaneous voltage drop or a power failure, and feeding the load from the AC / DC converter through the load transformer Parallel compensation type instantaneous voltage drop power failure countermeasure device,
A voltage correction amount for suppressing the bias magnetism of the load transformer is generated, and control means for controlling the AC / DC converter based on the voltage correction amount is provided ,
The control means includes load transformer magnetic flux correction means for generating the voltage correction amount based on a load voltage and a reference voltage supplied from the AC / DC converter to the load transformer,
The load transformer magnetic flux correction unit generates a magnetic flux change amount signal corresponding to the magnetic flux change amount of the load transformer based on the load voltage and the reference voltage, and the voltage based on the magnetic flux change signal. Generate a correction amount,
The load transformer magnetic flux correction means includes an integration circuit that generates the magnetic flux change amount signal based on a difference between the load voltage and the reference voltage,
The parallel compensation type instantaneous voltage drop power failure countermeasure device, wherein the magnetic flux change amount signal generated by the integration circuit is reset at regular intervals .   2. The parallel compensation instantaneous voltage drop power failure countermeasure device according to claim 1, wherein the load transformer magnetic flux correction unit stops outputting the voltage correction amount after a lapse of a predetermined time from the occurrence of the instantaneous voltage drop or the power failure. A grid interconnection switch is provided between an external input power supply and an external load, and an external load transformer is connected in series between the grid interconnection switch and the load, and the input power supply of the grid interconnection switch And an AC / DC converter connected to the load transformer side, disconnecting the grid interconnection switch in response to occurrence of an instantaneous voltage drop, and feeding the load from the AC / DC converter through the load transformer A series compensation type instantaneous voltage drop countermeasure device,
A voltage correction amount for suppressing the bias magnetism of the load transformer is generated, and control means for controlling the AC / DC converter based on the voltage correction amount is provided ,
The control means includes load transformer magnetic flux correction means for generating the voltage correction amount based on a load voltage and a reference voltage supplied from the AC / DC converter to the load transformer,
The load transformer magnetic flux correction unit generates a magnetic flux change amount signal corresponding to the magnetic flux change amount of the load transformer based on the load voltage and the reference voltage, and the voltage based on the magnetic flux change signal. Generate a correction amount,
The load transformer magnetic flux correction means includes an integration circuit that generates the magnetic flux change amount signal based on a difference between the load voltage and the reference voltage,
The series compensation type instantaneous voltage drop countermeasure device, wherein the magnetic flux change amount signal generated by the integration circuit is reset at regular intervals . A circuit breaker is provided between an external input power source and an external load, and an external load transformer is connected in series between the circuit breaker and the load, and parallel between the circuit breaker and the load transformer. A connected AC / DC converter, disconnecting the load from the commercial power system in response to an instantaneous voltage drop or power failure, and then starting a self-sustaining operation, independently from the commercial power system, from the AC / DC converter A parallel-connected AC / DC converter with a self-sustaining operation function for supplying power to the load through the load transformer,
A voltage correction amount for suppressing the bias magnetism of the load transformer is generated, and control means for controlling the AC / DC converter based on the voltage correction amount is provided ,
The control means includes load transformer magnetic flux correction means for generating the voltage correction amount based on a load voltage and a reference voltage supplied from the AC / DC converter to the load transformer,
The load transformer magnetic flux correction unit generates a magnetic flux change amount signal corresponding to the magnetic flux change amount of the load transformer based on the load voltage and the reference voltage, and the voltage based on the magnetic flux change signal. Generate a correction amount,
The load transformer magnetic flux correction means includes an integration circuit that generates the magnetic flux change amount signal based on a difference between the load voltage and the reference voltage,
The parallel connection type AC / DC converter with a self-sustaining operation function, wherein the magnetic flux change amount signal generated by the integration circuit is reset at regular intervals . A grid interconnection switch is provided between an external input power source and an external load, and an external load transformer is connected in series between the grid interconnection switch and the load, and the grid interconnection switch and the load transformer An AC / DC converter connected in parallel with the converter, disconnecting the grid connection switch in response to an instantaneous voltage drop or power failure, and connecting the load from the AC / DC converter connected in parallel through the load transformer An instantaneous voltage drop power failure countermeasure method using a parallel compensation type instantaneous voltage drop power failure countermeasure device that supplies power to
Including a control step of generating a voltage correction amount for suppressing the bias magnetism of the load transformer, and controlling the AC / DC converter based on the voltage correction amount ;
The control step includes a load transformer magnetic flux correction step for generating the voltage correction amount based on a load voltage and a reference voltage supplied from the AC / DC converter to the load transformer,
The load transformer magnetic flux correction step generates a magnetic flux change amount signal corresponding to the magnetic flux change amount of the load transformer based on the load voltage and the reference voltage, and the voltage based on the magnetic flux change amount signal. Generate a correction amount,
The load transformer magnetic flux correction step generates the magnetic flux change amount signal by an integration circuit based on a difference between the load voltage and the reference voltage,
The parallel compensation type instantaneous voltage drop power failure countermeasure method, wherein the magnetic flux change amount signal generated by the integration circuit is reset at regular intervals . A grid interconnection switch is provided between an external input power supply and an external load, and an external load transformer is connected in series between the grid interconnection switch and the load, and the input power supply of the grid interconnection switch And an AC / DC converter connected to the load transformer side, disconnecting the grid connection switch in response to occurrence of an instantaneous voltage drop, and connecting the load from the AC / DC converter connected in series through the load transformer An instantaneous voltage drop countermeasure method using a series compensation type instantaneous voltage drop countermeasure device that supplies power to
Including a control step of generating a voltage correction amount for suppressing the bias magnetism of the load transformer, and controlling the AC / DC converter based on the voltage correction amount ;
The control step includes a load transformer magnetic flux correction step for generating the voltage correction amount based on a load voltage and a reference voltage supplied from the AC / DC converter to the load transformer,
The load transformer magnetic flux correction step generates a magnetic flux change amount signal corresponding to the magnetic flux change amount of the load transformer based on the load voltage and the reference voltage, and the voltage based on the magnetic flux change amount signal. Generate a correction amount,
The load transformer magnetic flux correction step generates the magnetic flux change amount signal by an integration circuit based on a difference between the load voltage and the reference voltage,
The series compensation type instantaneous voltage drop countermeasure method, wherein the magnetic flux change amount signal generated by the integration circuit is reset at regular intervals . A circuit breaker is provided between an external input power source and an external load, and an external load transformer is connected in series between the circuit breaker and the load, and parallel between the circuit breaker and the load transformer. An AC / DC converter connected to the AC / DC converter, disconnecting the load from the commercial power system in response to an instantaneous voltage drop or power failure, and then starting a self-sustaining operation independently of the commercial power system. An AC / DC conversion method using a parallel-connected AC / DC converter with a self-sustaining operation that feeds power to the load through the load transformer,
Including a control step of generating a voltage correction amount for suppressing the bias magnetism of the load transformer, and controlling the AC / DC converter based on the voltage correction amount ;
The control step includes a load transformer magnetic flux correction step for generating the voltage correction amount based on a load voltage and a reference voltage supplied from the AC / DC converter to the load transformer,
The load transformer magnetic flux correction step generates a magnetic flux change amount signal corresponding to the magnetic flux change amount of the load transformer based on the load voltage and the reference voltage, and the voltage based on the magnetic flux change amount signal. Generate a correction amount,
The load transformer magnetic flux correction step generates the magnetic flux change amount signal by an integration circuit based on a difference between the load voltage and the reference voltage,
The parallel connection type AC / DC conversion method with independent operation function, wherein the magnetic flux change amount signal generated by the integration circuit is reset at regular intervals .

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