JP2006067673A - Power supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a power supply apparatus being employed in a power storage unit or a power generation facility in which voltage rise of a system is suppressed and, at the same time, superfluous power is reused or power generated from the power generation facility is utilized effectively. <P>SOLUTION: Since a voltage stabilizer 1 comprising a full-bridge converter 5, a full-bridge inverter 6, a capacitor 7, a series transformer 10, and a main circuit control section 11 is provided with a power accumulation means 12, power can be supplied with stabilized voltage to a load and when the voltage of an AC power supply 8 is high, the power accumulation means 12 can be charged with excess power for voltage stabilization. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power supply device using inverter technology.

  In recent years, fossil fuel depletion and global warming have occurred due to an increase in the load on ordinary households. Use of clean energy and energy-saving devices such as solar power generation systems, power-saving devices, and system voltage stabilization devices have been developed. It has been demanded.

  Conventionally, this type of power supply device can output a current including a phase advance invalid component as a grid-connected power conversion device that links the generated power of the power generator to the grid side, and can reduce power consumption of a consumer load. Is known (see, for example, Patent Document 1).

  Hereinafter, the power supply apparatus will be described with reference to FIGS. 16 and 17.

As shown in FIG. 16, when a current Iinv including a phase advance invalid component is output from the grid interconnection inverter 101 to the distribution system 102, the supply voltage Vline = Vinv to the consumer general load 103 becomes the grid impedance 104 to the grid voltage Vg. A value obtained by adding the voltage drop Vdif at (R + j × L). FIG. 17A is an active power adjustment mode in which sunlight is radiated and the DC power supply supplies active power to the distribution system 102. The grid-connected inverter 101 converts DC power from the DC power supply into AC power. And the vector diagram at the time of supplying electric power to the power distribution system 102 and the consumer general load 103 is shown. In this operation mode, the normal load voltage Vline is higher than the system voltage Vg. Next, FIG. 17B shows a vector diagram when the reactive power is supplied to the power distribution system 102 and the consumer general load 103 at the same time by changing the control of the grid interconnection inverter 101. In this case, as shown in the figure, the load voltage Vline is lower than the system voltage Vg, and the active power and the reactive power are appropriately controlled in consideration of the constant of the system impedance 104, thereby supplying the consumer general load 103. The load voltage Vline can be controlled to a voltage value lower than the rated voltage within a range equal to or higher than the operable lower limit voltage. Therefore, the supply voltage to the consumer general load 103 can be controlled to be lower than the rated voltage, and the power consumption of the consumer general load 103 can be reduced.
JP 2003-153444 A

  In such a conventional power supply device, the power generated by the power generation device increases, and there is a problem that current output including a phase advance invalid component alone is insufficient, and there is a problem that an increase in system voltage cannot be suppressed. It is required to suppress the increase in voltage and to effectively use the power generated by the power generator.

  In addition, since power factor 1 control is the basis during normal times, it is detected that the system voltage has risen and is controlled so as to lower the system voltage by feedback control. There exists a subject that the effective utilization rate of generated electric power falls, and it is requested | required to make the protection coordination of a system | strain compatible with the effective utilization of generated electric power.

  Furthermore, the power supply voltage supplied to the load and the power supply voltage on the AC power supply side cannot be automatically controlled to the specified range at the same time, the power supply voltage supplied to the load increases, and the power consumption of the load increases. There is a need for a power supply apparatus that simultaneously reduces the amount of power consumed by the load simultaneously with system protection coordination.

  In addition, there is a problem that a transient voltage increase occurs due to responsiveness to the system voltage because of feedback control based on the result that the system voltage exceeds the specified value. There is a demand for feedforward control that can control the voltage.

  The present invention solves such a conventional problem, and even when the excessive power saved by the power saving device or the voltage stabilizing device corresponding to the power generation device increases, the excessive power is charged to the storage battery. It is an object of the present invention to provide a power supply device capable of controlling the supply voltage to the load to an optimum voltage.

  It is another object of the present invention to provide a power supply apparatus that can automatically control a power supply voltage supplied to a load and a power supply voltage on an AC power supply side simultaneously within a specified range.

  Furthermore, the present invention automatically detects the impedance of the system, determines the output power that does not increase the system voltage beyond the specified value from the detected impedance and system voltage, without causing a voltage increase on the system side, It is another object of the present invention to provide a power supply device that can effectively use excess power saved by a power saving device or a voltage stabilizing device.

  It is another object of the present invention to provide a power supply apparatus that can perform feedforward control before reaching the specified value, instead of feedback control based on the result that the system voltage becomes equal to or higher than the specified value.

  In order to achieve the above object, the power supply device of the present invention has a full bridge converter configured by three arms in which diodes antiparallel to switching elements are connected in series vertically, and a full bridge sharing one arm with the full bridge converter. An inverter, a capacitor connected in parallel to the three arms, a series transformer in which an AC power source and a primary winding are connected in series, and a secondary winding is connected in series from the output of the full bridge inverter through a reactor; In the power-saving device constituted by the main circuit control unit for controlling the full-bridge converter and the full-bridge inverter, or the voltage stabilizing device, it is connected in parallel to the capacitor and is charged / discharged according to the vertical fluctuation of the voltage of the AC power source. The power storage means is configured to be provided.

  By this means, excess power from the full-bridge inverter can be stored in the storage means, and when the voltage of the AC power supply drops, it can be supplied to the load side or reversely flowed to the AC power supply side. A power supply device capable of stabilizing the power supply voltage is obtained.

  Further, the control unit of the full bridge converter and the charge / discharge control unit of the power storage means are controlled to have different capacitor voltages.

  By this means, it is possible to provide a control time constant by increasing or decreasing the capacitor voltage, smoothly performing charge / discharge control of the storage means and current control of the full bridge converter, and generating overvoltage and undervoltage of the capacitor. Can be eliminated.

  Further, the capacitor control voltage when charging the power storage means is configured to be different from the capacitor control voltage when discharging.

  By this means, charging and discharging of the power storage means can be performed smoothly.

  Further, the capacitor control voltage during regeneration of the full bridge converter is configured to be different from the capacitor control voltage during power running.

  By this means, the regeneration of the full bridge converter and the switching control of the power running can be performed smoothly, and it is possible to eliminate the occurrence of the capacitor overvoltage and undervoltage.

  Furthermore, the system voltage control means for controlling the voltage of the AC power supply and the load voltage control means for controlling the voltage of the power supply supplied to the load side are provided.

  By this means, the voltage of the AC power supply and the voltage supplied to the load can be automatically controlled to the specified range at the same time.

  In addition, it is configured to include feedforward control means for preventing the voltage increase or decrease of the AC power source.

  By this means, feed-forward control before reaching the specified value can be performed instead of feedback control based on the result that the system voltage becomes equal to or higher than the specified value.

  Furthermore, the configuration includes impedance determining means for determining the impedance of the AC power supply, and converter output limiting means for limiting the output of the full bridge converter from the impedance determined by the impedance determining means.

  By this means, the impedance of the AC power supply is automatically detected in advance, so that excessive power output to the AC power supply side can be avoided, and occurrence of a voltage increase of the AC power supply can be eliminated.

  Further, the feedforward control means for preventing the voltage increase or decrease of the AC power supply is constituted by an impedance determination means and a converter output limiting means.

  By this means, feed-forward control before reaching the specified value can be performed instead of feedback control based on the result that the system voltage becomes equal to or higher than the specified value.

  Further, the impedance determination means is configured to determine from the correlation between the voltage increase of the AC power supply and the converter output.

  By this means, the impedance of the AC power supply can be determined by an internal calculation, so there is no need to input the impedance of the AC power supply through communication, and the circuit configuration can be simplified.

  In addition, an inductance determination unit that determines the inductance of the AC power source and a reactive power control unit that controls the amount of reactive power output from the full bridge converter using the inductance determined by the inductance determination unit are provided.

  By this means, the impedance of the AC power source can be automatically determined by internal calculation, and the output of reactive power can be minimized and excellent response can be ensured.

  Furthermore, a configuration comprising voltage monitoring means for constantly monitoring the power supply voltage of the AC power supply and second reactive power control means for controlling the amount of reactive power output from the full bridge converter when the power supply voltage detected by the voltage monitoring means rises It is what.

  By this means, it consists of feedforward control of reactive power output to suppress voltage rise of AC power supply by automatic determination of impedance of AC power supply and feedback control from power supply voltage rise detected by voltage monitoring means, so it is finer Therefore, it is possible to secure the minimum necessary and better response.

  Moreover, it is set as the structure provided with the surplus electric power control means which stores the surplus electric power produced by the output restriction | limiting of a full bridge converter in an electrical storage means.

  By this means, even when the output of the full bridge converter is limited, surplus power can be temporarily stored in the power storage means, and the past power stored when the output limit is canceled or falls below the output limit value is stored. The saved excess power can be output, and the excess power obtained by the power saving device or the voltage stabilization device can be used effectively.

  Furthermore, the configuration is provided with inverter limiting means for limiting the output of the full bridge inverter when the output of the full bridge converter is limited and the surplus power control stored in the power storage means is limited.

  By this means, the power supply voltage of the AC power supply can be operated within the specified range by limiting the output of the full bridge converter and the excessive power to be saved even when the storage battery is almost fully charged. Can do.

  According to the present invention, a full-bridge converter constituted by three arms in which diodes antiparallel to switching elements are connected in series up and down, a full-bridge inverter sharing one arm with a full-bridge converter, and the three arms A capacitor connected in parallel, an AC power source and a primary winding connected in series, and a series transformer in which a secondary winding is connected in series from the output of the full bridge inverter through a reactor, the full bridge converter, and the full bridge inverter In a power saving device or a voltage stabilization device configured by a main circuit control unit for controlling the power supply, the power storage device is connected in parallel to the capacitor and includes a power storage unit that charges and discharges according to the vertical fluctuation of the voltage of the AC power supply. The excess power from the full-bridge inverter A power supply device that can be supplied to the load side when the voltage of the AC power source drops or can flow backward to the AC power source side and can control the AC power source voltage to the optimum voltage. Can be provided.

  In addition, by setting the control unit of the full bridge converter and the charge / discharge control unit of the power storage means to control the capacitor voltage differently, it is possible to provide a control time constant by increasing or decreasing the capacitor voltage, Thus, it is possible to provide a power supply apparatus that can smoothly perform charging / discharging control of the power storage means and current control of the full bridge converter, and can eliminate the occurrence of overvoltage and undervoltage of the capacitor.

  Furthermore, the capacitor control voltage at the time of charging the power storage means is controlled to a voltage different from the capacitor control voltage at the time of discharge, so that charging and discharging of the power storage means can be performed smoothly. A power supply can be provided.

  In addition, the capacitor control voltage during regeneration of the full bridge converter is controlled to be different from the capacitor control voltage during power running, so that the charge / discharge command of the power storage means can be substituted with the capacitor voltage. Therefore, it is possible to provide a power supply device that is effective in that the configuration can be simplified without requiring communication means.

  Furthermore, the system voltage control means for controlling the voltage of the AC power supply and the load voltage control means for controlling the voltage of the power supply to the load side are provided, so that the voltage of the AC power supply and the voltage supplied to the load can be reduced. At the same time, it is possible to provide a power supply device that can be automatically controlled within a specified range.

  In addition, by adopting a configuration including a feedforward control means for preventing an increase or a decrease in the voltage of the AC power source, feedback control based on a result that the system voltage becomes equal to or higher than the specified value, but before reaching the specified value It is possible to provide a power supply device having an effect that feedforward control can be performed.

  Furthermore, the impedance determination means for determining the impedance of the AC power supply, and the converter output limiting means for limiting the output of the full bridge converter from the impedance determined by the impedance determination means, the impedance of the AC power supply is known in advance. Therefore, it is possible to provide a power supply device that can avoid an excessive reverse power flow and can eliminate an increase in the voltage of the AC power supply.

  In addition, the feedforward control means for preventing the voltage increase or decrease of the AC power supply in advance is configured by the impedance determination means and the converter output limiting means, so that feedback control based on the result that the system voltage becomes a specified value or more is possible. In addition, it is possible to provide a power supply device that can perform feedforward control before reaching the specified value.

  Further, the impedance determination means is configured to determine from the correlation between the voltage increase of the AC power supply and the converter output, so that the impedance of the AC power supply can be determined by an internal calculation, so that the circuit configuration can be simplified. It is possible to provide a power supply device that has the effect of being able to.

  In addition, an inductance determination unit that determines the inductance of the AC power source, and a reactive power control unit that controls the reactive power amount output from the full bridge converter with the inductance determined by the inductance determination unit, The impedance can be automatically determined by an internal calculation, and a power supply apparatus having an effect that the output of reactive power can be minimized and excellent responsiveness can be ensured can be provided.

  Also, a configuration comprising voltage monitoring means for constantly monitoring the power supply voltage of the AC power supply, and second reactive power control means for controlling the amount of reactive power output from the full bridge converter when the power supply voltage detected by the voltage monitoring means rises Because it is composed of feedforward control of suppression of voltage rise of AC power supply with reactive power output by automatic determination of impedance of AC power supply, and feedback control from power supply voltage rise detected by voltage monitoring means, It is possible to provide a power supply device that is effective in being capable of ensuring fine response with a fine and necessary minimum.

  Further, the power storage means is provided with a surplus power control means for storing the surplus power generated by the output restriction of the full bridge converter in the power storage means, so that even if the output restriction of the full bridge converter occurs, the power storage means temporarily Can store the surplus power, and when the output limit is canceled or the output limit value is exceeded, the past saved surplus power can be output and saved by the power saving device or voltage stabilization device It is possible to provide a power supply device having an effect that the excess power can be effectively used.

  In addition, when the limit of the output of the full bridge converter and the limit of surplus power control stored in the storage means are provided, the inverter is provided with an inverter limiting means for limiting the output of the full bridge inverter, so that output to the AC power supply side is impossible. In addition, even when the storage battery is almost fully charged, by limiting the power of the full-bridge inverter, a power supply device that can operate the AC power supply voltage within the specified range Can be provided.

  The invention according to claim 1 of the present invention is a full bridge converter configured by three arms in which diodes antiparallel to switching elements are connected in series vertically, and a full bridge inverter sharing one arm with the full bridge converter, A capacitor connected in parallel to the three arms, a series transformer in which an AC power source and a primary winding are connected in series, and a secondary winding is connected in series from the output of a full bridge inverter through a reactor; and the full bridge In a power saving device constituted by a main circuit control unit for controlling a converter, a full bridge inverter, or a voltage stabilizing device, a power storage means connected in parallel to the capacitor and charging / discharging according to the vertical fluctuation of the voltage of the AC power supply With excess power from a full-bridge inverter. Can be the power storage to the energy storage means, the voltage of the AC power supply has an effect of being able to reverse flow supply, or to the AC power supply side to the load side when lowered.

  In addition, the control unit of the full bridge converter and the charge / discharge control unit of the power storage means are configured to control different capacitor voltages, and a control time constant can be provided by increasing or decreasing the capacitor voltage. The charging / discharging control of the means and the current control of the full bridge converter are smoothly performed, and it is possible to eliminate the occurrence of overvoltage and undervoltage of the capacitor.

  Further, the capacitor control voltage at the time of charging the power storage means is controlled to a voltage different from the capacitor control voltage at the time of discharging, and the function of smoothly switching between charging and discharging of the power storage means. Have

  In addition, the capacitor control voltage during regeneration of the full bridge converter is controlled to be a voltage different from the capacitor control voltage during power running, and the charge / discharge command of the storage means is substituted with the capacitor voltage. Therefore, the communication means is not required and the configuration can be simplified.

  Furthermore, the system voltage control means for controlling the voltage of the AC power supply and the load voltage control means for controlling the voltage of the power supply supplied to the load side are provided, and the voltage of the AC power supply and the voltage supplied to the load are provided. Can be controlled automatically within a specified range at the same time.

  In addition, it is configured to have a feedforward control means for preventing the voltage increase or decrease of the AC power supply before it reaches the specified value rather than the feedback control based on the result that the system voltage exceeds the specified value. The feedforward control can be performed.

  Furthermore, it is configured to include an impedance determination unit that determines the impedance of the AC power source and a converter output limiting unit that limits the output of the full bridge converter from the impedance determined by the impedance determination unit, and the impedance of the AC power source is known in advance. Therefore, an excessive reverse power flow can be avoided, and the occurrence of an increase in voltage of the AC power supply can be eliminated.

  In addition, the feedforward control means for preventing an increase or decrease in the voltage of the AC power source is constituted by an impedance determination means and a converter output limiting means, and feedback control based on the result of the system voltage exceeding a specified value. In addition, the feedforward control before reaching the specified value can be performed.

  Furthermore, the impedance determination means is configured to determine from the correlation between the voltage increase of the AC power supply and the converter output, and the impedance of the AC power supply can be determined by internal calculation, thus simplifying the circuit configuration. Has the effect of being able to

  In addition, an inductance determination unit that determines the inductance of the AC power source, and a reactive power control unit that controls the amount of reactive power output from the full bridge converter using the inductance determined by the inductance determination unit. The impedance can be automatically determined by internal calculation, and has the effect that the output of reactive power can be minimized and excellent responsiveness can be ensured.

  Furthermore, a configuration comprising voltage monitoring means for constantly monitoring the power supply voltage of the AC power supply and second reactive power control means for controlling the amount of reactive power output from the full bridge converter when the power supply voltage detected by the voltage monitoring means rises Because it is configured by feedforward control of reactive power output to suppress voltage rise of AC power supply by automatic determination of impedance of AC power supply and feedback control from power supply voltage rise detected by voltage monitoring means, It has the effect of being able to ensure a finer and more necessary minimum and better response.

  In addition, it is configured to include surplus power control means for storing surplus power generated by the output restriction of the full bridge converter in the power storage means, and even when output restriction of the full bridge converter occurs, Surplus power can be temporarily stored, and when the output limit is canceled or the output limit value is exceeded, the past saved excess power can be output, and the excess saved by the power saving device or voltage stabilization device It has an effect that the electric power can be effectively used.

  Further, the output limit of the full bridge converter, and at the limit of surplus power control stored in the power storage means, it is configured to include an inverter limit means for limiting the output of the full bridge inverter, the output limit of the full bridge converter, and Even when the storage battery is almost fully charged, by limiting the power of the full bridge inverter, the power supply voltage of the AC power supply can be operated within the specified range.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of a power supply device according to the first embodiment.

  As shown in the figure, the voltage stabilizing device 1 as a load voltage control means for controlling the supply voltage to the load side includes three arms 4a to 4c in which diodes 3 in reverse parallel to the switching elements 2 are connected in series up and down. The constructed full bridge converter 5, a full bridge inverter 6 sharing one arm 4b with the full bridge converter 5, a capacitor 7 connected in parallel to the three arms 4a to 4c, an AC power source 8, and a primary winding A series transformer 10 connected in series and having a secondary winding connected in series from the output of the full bridge inverter 6 through a reactor 9, and the main circuit controller 11 for controlling the full bridge converter 5 and the full bridge inverter 6. Composed. Further, in parallel with the capacitor 7 of the voltage stabilizing device 1, the system voltage is charged when the power supply voltage of the AC power supply 8 rises, and when the power supply voltage drops, the voltage of the AC power supply 8 that controls the discharge is controlled. Power storage means 12 is provided as control means.

  Next, FIG. 2 shows a control flowchart of the main circuit control unit 11.

  As shown in the figure, the control of the full bridge inverter 6 of the main circuit control unit 11 inputs the power supply voltage supplied to the load, and calculates the deviation from the set voltage. The deviation from the set voltage is input to the PI controller, and the output voltage of the full bridge inverter 6 is calculated. Further, the control of the full bridge converter 5 of the main circuit control unit 11 is configured to control the voltage of the capacitor 7 to be constant. By inputting the voltage of the capacitor 7 and performing PI control from the difference value from the target voltage of the capacitor 7, the voltage of the capacitor 7 is controlled to be constant. A command value for current output to the AC power supply 8 is calculated as a command value by inputting a deviation between the voltage Vt of the capacitor 7 and the target voltage Vt * to the PI controller. The target voltage Vt * at this time is Vta * during power running and Vtb * during regeneration, and Vta * is lower than Vtb *.

  Next, the operation as the voltage stabilizing device 1 will be described with reference to FIG.

  In the figure, a series transformer 10 is connected to the output terminal of the full bridge inverter 6 through a reactor 9, and the turn ratio of the primary and secondary windings of the series transformer 10 is N1 to N2. The voltage on the primary winding side of the series transformer 10 is N1 / N2 times the output voltage of the full bridge inverter 6. Accordingly, when the voltage phase of the AC power supply 8 and the voltage phase of the primary winding are in phase, a voltage obtained by subtracting the voltage of the primary winding from the power supply voltage of the AC power supply 8 is applied to the load. Conversely, if the voltage phase of the AC power supply 8 and the voltage phase on the primary winding side are in reverse phase, a voltage obtained by adding the voltage of the primary winding to the power supply voltage of the AC power supply 8 is applied to the load. Therefore, the target voltage of the full bridge inverter 6 is determined by the correlation between the set voltage supplied to the load and the AC power supply 8. The full bridge converter 5 controls the voltage of the capacitor 7 to be constant, and at the same time outputs a current to the AC power supply 8 with a power factor of 1 when the set voltage supplied to the load is lower than the power supply voltage of the AC power supply 8. Further, the full bridge converter 5 is basically controlled so as to draw a current into the AC power supply 8 with a power factor of 1 when the set voltage supplied to the load is higher than the power supply voltage of the AC power supply 8.

  Next, a control flowchart of the power storage unit 12 will be described with reference to FIG.

  The power storage means 12 includes a lead storage battery 12a and a bidirectional converter 12b. By inputting a deviation between the voltage Vt of the capacitor 7 and a target voltage Vt2 * used for controlling the power storage means 12, to the PI controller, Calculate charge / discharge current command value. At this time, the target voltage Vcha * at the time of charging the power storage means 12 is set to a voltage higher than the target voltage Vdis * at the time of discharging. The target voltage Vt * of the capacitor 7 by the full bridge converter 5 is set to a voltage between Vcha * and Vdis *. By separating the charge / discharge target voltage by Vcha * and Vdis *, the charge / discharge is controlled according to the vertical fluctuation of the power supply voltage of the AC power supply 8.

  As described above, according to the first embodiment, power is supplied to a load at a stable voltage, and when the power of the AC power supply 8 is high with excessive power for voltage stabilization, the power storage means 12 can be charged with excess power. Further, when insufficient power for voltage stabilization occurs and the voltage of the AC power supply 8 is low, the insufficient power can be discharged from the power storage means 12. Further, the voltage of the capacitor 7 can be provided with a control time constant by increasing or decreasing the capacitor voltage by controlling the target voltage of the full bridge converter 5 and the target voltage of the power storage means 12 to different voltages. The charge / discharge control of the power storage means and the current control of the full bridge converter can be smoothly performed, and the occurrence of overvoltage and undervoltage of the capacitor can be eliminated. In addition, the target voltage of the capacitor 7 is lowered during power running and increased during regeneration, so that the power storage means 12 performs power running regeneration operation of the control unit of the full bridge converter 5 and the full bridge inverter 6 by monitoring the voltage of the capacitor 7. Can be determined.

  In the present embodiment, a lead storage battery is used as the storage medium of the storage means 12, but an electric double layer capacitor, a nickel hydrogen battery, a lithium ion battery, or the like may be used.

(Embodiment 2)
FIG. 5 is a configuration diagram of the power supply device according to the second embodiment.

  As shown in the figure, the voltage stabilizing device 1 outputs the impedance from the full bridge converter 5 to the AC power supply 8 by the impedance determination means 14 for detecting and determining the impedance of the AC power supply 8 as the feedforward control means 13 and the detected impedance. Converter output limiting means 15 for limiting power is provided.

  FIG. 6 shows a flowchart of the impedance determination means 14.

  As shown in the figure, the impedance determination unit 14 commands the main circuit control unit 11 to output effective current Iw so that the output current from the full bridge converter 5 becomes the maximum Iw. The power supply voltage V1 of the AC power supply 8 when the output effective current Iw of the full bridge converter 5 is detected and stored. Next, the impedance determination means 14 outputs a command to the full-bridge converter 5 so as to change the power factor of the output current to 0.85 to the main circuit controller 11 so that the effective current is Iw and the reactive current Iq is simultaneously output. To do. The fluctuating power supply voltage V2 of the AC power supply 8 is detected. Next, the output of the full bridge converter 5 is set to zero, and the power supply voltage Vo of the AC power supply 8 at that time is detected. At this time, as for the relationship among Vo, V1, V2, Iw, and Iq, simultaneous equations are established by Equation 1 when the impedance of the AC power supply 8 is Rs + jXs. When Formula 1 is solved for Rs and Xs, Formula 2 can be derived.

  Furthermore, from the obtained Rs, Xs and the maximum allowable voltage Vmax of the AC power supply 8 and the power supply voltage Vo of the AC power supply 8 when the output from the full bridge converter 5 is zero, the maximum current that can be regenerated from the full bridge converter 5 Iw_max can be calculated by Equation 3.

  Next, a flowchart of the converter output limiting means 15 will be described with reference to FIG.

  As shown in the figure, the converter output limiting means 15 receives the maximum regenerative current Iw_max calculated by the impedance determination means 14. The input current maximum value Iw_max and the output rated current Icon_max of the full bridge converter 5 are compared. A set value is output to the main circuit control unit 11 using any lower current value as a maximum output current limiter.

  As described above, according to the second embodiment, the impedance determination unit 14 can detect and determine the impedance of the AC power supply 8. Further, the maximum current that can be regenerated from the full bridge converter 5 is calculated from the impedance of the AC power supply 8 detected and determined by the impedance determination means 14, and the output current is limited by the converter output limiting means 15. By this output current limit, excessive reverse power flow can be avoided, and the occurrence of voltage increase of the AC power supply 8 can be eliminated.

(Embodiment 3)
FIG. 8 shows a configuration diagram of the power supply device according to the third embodiment.

  As shown in the figure, the power supply apparatus according to the third embodiment includes an inductance determining unit 16 that determines the inductance of the AC power supply 8 and an invalidity that outputs reactive power from the full bridge converter 5 with the inductance determined by the inductance determining unit 16. Power control means 17 is provided.

  FIG. 9 shows a flowchart of the inductance determining means 16.

  As shown in the figure, the inductance determining means 16 commands the main circuit control unit 11 to output effective current Iw so that the output current from the full bridge converter 5 becomes the maximum Iw. The power supply voltage V1 of the AC power supply 8 when the output effective current Iw of the full bridge converter 5 is detected and stored. Next, the inductance determination means 16 outputs a command to the full-bridge converter 5 so as to change the power factor of the output current to 0.85 to the main circuit control unit 11 so that the effective current is Iw and the reactive current Iq is simultaneously output. To do. The fluctuating power supply voltage V2 of the AC power supply 8 is detected. Next, the output of the full bridge converter 5 is set to zero, and the power supply voltage Vo of the AC power supply 8 at that time is detected. At this time, as for the relationship among Vo, V1, V2, Iw, and Iq, simultaneous equations are established by Equation 4 when the impedance of the AC power supply 8 is Rs + jXs. When Formula 4 is solved for Xs, Formula 5 can be derived.

  Further, from the obtained Rs, Xs and the maximum allowable voltage Vmax of the AC power supply 8 and the power supply voltage Vo of the AC power supply 8 when the output from the full bridge converter 5 is zero, invalidity when the power factor is 0.85. The maximum power value Iq_max is calculated.

  Next, the flowchart of the reactive power control means 17 will be described with reference to FIG.

  As shown in the figure, the reactive current Iq_max is a value obtained by multiplying Iw_max by a constant 0.62 because the power factor is 0.85. Accordingly, the reactive power control unit 17 determines whether the vector sum of the maximum value Iq_max of reactive power and the maximum value Iw_max of active power exceeds the rated current of the full bridge converter 5. If the rated current exceeds the rated current, the vector sum is updated to the rated current, and the value obtained by multiplying the rated current by 0.85 is updated to Iw_max, and the updated Iw_max is multiplied by 0.62 to Iq_max. To do.

  As described above, according to the third embodiment, the inductance determining unit 16 can detect and determine the inductance of the AC power supply 8. In addition, the maximum current that can be regenerated from the full bridge converter 5 is calculated from the inductance of the AC power supply 8 detected and determined by the inductance determining means 16, and the output current is limited by the reactive power control means 17. With this output current limit, excessive reverse power flow can be avoided, and at the same time, the output of reactive power can be minimized and the occurrence of voltage increase of the AC power supply 8 can be eliminated.

(Embodiment 4)
FIG. 11 is a configuration diagram of the power supply device according to the fourth embodiment.

  As shown in the figure, the power supply device according to the fourth embodiment includes a voltage sensor 18a as voltage monitoring means 18 that constantly monitors the power supply voltage of the AC power supply 8, and a voltage conversion unit that converts a detection signal from the voltage sensor 18a into a voltage value. 18 b and second reactive power control means 19 for outputting reactive power from the full bridge converter 5 when the power supply voltage detected by the voltage monitoring means 18 rises.

  Next, the control block of the second reactive power control means 19 will be described with reference to FIG.

  As shown in the figure, the second reactive power control means 19 is a power supply detected by the feedforward control section for suppressing the voltage rise of the AC power supply 8 by the reactive power output by automatic determination of the impedance of the AC power supply 8 and the voltage monitoring means 18. And a feedback control unit that performs control from voltage rise. The steady output is limited by the feedforward control based on the automatic determination of the impedance, and the transient limitation is performed by the feedback control from the rise of the power supply voltage detected by the voltage monitoring means 18.

  As described above, according to the fourth embodiment, the voltage monitoring means 18 and the second reactive power control means 19 can suppress an increase in the power supply voltage of the AC power supply 8. With this feedforward control and feedback control, it is possible to ensure more detailed and necessary minimum and superior reactive power control responsiveness.

(Embodiment 5)
FIG. 13 is a configuration diagram of the power supply device according to the fifth embodiment.

  As shown in the figure, the power supply device according to the fifth embodiment includes a surplus power control unit 20 that stores surplus power generated by the output limitation of the full bridge converter 5 in the power storage unit 12, an output limitation of the full bridge converter 5, In addition, an inverter limiting means 21 for limiting the excess power saved by the voltage stabilizing device 1 at the limit of surplus power control stored in the power storage means 12 is provided.

  Next, the control block of the surplus power control means 20 will be described with reference to FIG.

  As shown in the figure, the surplus power control means 20 inputs an output command of the full bridge converter 5. The input output command is input to the PI controller, and the feed forward term of the charging current command value stored in the power storage means 12 is calculated. Next, voltage information of the capacitor 7 is input, input to the PI controller so as to keep the voltage of the capacitor 7 at a constant voltage Vcon, and a feedback term of a charging current command value stored in the storage means 12 is calculated. The final charge current command value is calculated by adding the calculated feedforward term and feedback term. When the surplus power control means 20 calculates a current command value on the discharge side, current control is performed as a discharge command.

  Next, a flowchart of the inverter limiting means 21 will be described with reference to FIG.

  As shown in the figure, the inverter control means 21 inputs the command current value of the full bridge converter 5 and further compares the rated current value of the full bridge converter 5. As a result of comparison, when the rated current value is exceeded, control is performed so as to lower the voltage command value of the full bridge inverter 6.

  As described above, according to the fifth embodiment, even when the output of full bridge converter 5 is limited, surplus power can be temporarily stored in power storage means 12, and output restriction can be released or output can be limited. When the value falls below the value, the past saved excess power stored can be output, and the saved excess power obtained by the voltage stabilizing device 1 can be used effectively. In addition, the power supply voltage of the AC power supply 8 is operated within the specified range by limiting the output of the full bridge converter 5 and the excessive power to be saved even when the storage battery is almost fully charged. Will be able to.

  Since the power generation means using solar cells and fuel cells can be easily connected to the capacitor in parallel, the generated power can be easily peak shifted using the power storage means. It can also be applied to households that require power, and by automatically determining the impedance on the AC power supply side, output suppression during grid interconnection can be predicted in advance, so that harmony with the system side is aimed at It can also be applied to centralized interconnection applications where necessary.

1 is a configuration diagram of a power supply device according to a first embodiment of the present invention. Control flowchart of the main circuit control unit 11 Operation explanatory diagram as the voltage stabilizing device 1 Control flow chart of the electricity storage means 12 Configuration diagram of power supply apparatus according to Embodiment 2 of the present invention Flow chart of the impedance determination means 14 Flowchart of the converter output limiting means 15 Configuration diagram of power supply device according to Embodiment 3 of the present invention Flow chart of the inductance determination means 16 Flow chart of the reactive power control means 17 Configuration diagram of power supply device according to embodiment 4 of the present invention Control block diagram of the second reactive power control means 19 Configuration diagram of power supply device according to embodiment 5 of the present invention Control block diagram of the surplus power control means 20 Flow chart of the inverter limiting means 21 Block diagram of a conventional power supply (system-connected inverter) Vector diagram when controlling the supply voltage

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage stabilizer 2 Switching element 3 Diode 4 Arm 5 Full bridge converter 6 Full bridge inverter 7 Capacitor 8 AC power supply 9 Reactor 10 Series transformer 11 Main circuit control part 12 Power storage means 13 Feed forward control means 14 Impedance judgment means 15 Converter Output limiting means 16 Inductance determination means 17 Reactive power control means 18 Voltage monitoring means 19 Second reactive power control means 20 Surplus power control means 21 Inverter limiting means

Claims (13)

A full bridge converter composed of three arms vertically connected in series with a diode parallel to the switching element, a full bridge inverter sharing one arm with the full bridge converter, and a capacitor connected in parallel to the three arms; A series transformer in which an AC power source and a primary winding are connected in series and a secondary winding is connected in series from the output of the full bridge inverter through a reactor, and the main circuit control for controlling the full bridge converter and the full bridge inverter A power-saving device comprising: a power-saving device or a voltage stabilizing device, comprising a power storage means connected in parallel to the capacitor and charging / discharging in accordance with up / down fluctuations in the voltage of the AC power supply. 2. The power supply apparatus according to claim 1, wherein the controller of the full bridge converter and the charge / discharge controller of the power storage means are controlled to different capacitor voltages. 3. The power supply device according to claim 2, wherein the capacitor control voltage at the time of charging the power storage means is made different from the capacitor control voltage at the time of discharging. A power supply apparatus comprising system voltage control means for controlling a voltage of an AC power supply and load voltage control means for controlling a voltage of a power supply supplied to a load side. A power supply apparatus comprising feedforward control means for preventing an increase or decrease in voltage of an AC power supply. 4. The power supply device according to claim 1, wherein the capacitor control voltage during regeneration of the full bridge converter is made different from the capacitor control voltage during power running. 7. An impedance determining means for determining an impedance of an AC power source and a converter output limiting means for limiting the output of the full bridge converter from the impedance determined by the impedance determining means. The power supply device described in 1. 6. The power supply apparatus according to claim 5, wherein the feedforward control means is an impedance determination means and a converter output limiting means. The power supply apparatus according to claim 7 or 8, wherein the impedance determination means determines from a correlation between a voltage increase of the AC power supply and a converter output. 3. An inductance determining means for determining an inductance of an AC power source, and a reactive power control means for controlling an amount of reactive power output from the full bridge converter with the inductance determined by the inductance determining means. The power supply device according to 3, 6, 7, 8, or 9. Voltage monitoring means for constantly monitoring the power supply voltage of the AC power supply, and second reactive power control means for controlling the amount of reactive power output from the full bridge converter when the power supply voltage detected by the voltage monitoring means rises. 11. The power supply apparatus according to claim 1, 2, 3, 6, 7, 8, 9, or 10. 12. A surplus power control means for storing surplus power generated by the output limitation of the full bridge converter in a power storage means is provided. The power supply device described in 1. 8. An inverter limiting means for limiting the output of a full bridge inverter at the time of limit of output of a full bridge converter and control of surplus power stored in the power storage means. , 8, 9, 10, 11, or 12.

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