WO2023054406A1 - Dc bus control system - Google Patents

Dc bus control system Download PDF

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Publication number
WO2023054406A1
WO2023054406A1 PCT/JP2022/036033 JP2022036033W WO2023054406A1 WO 2023054406 A1 WO2023054406 A1 WO 2023054406A1 JP 2022036033 W JP2022036033 W JP 2022036033W WO 2023054406 A1 WO2023054406 A1 WO 2023054406A1
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Prior art keywords
power
bus
charging
current
discharging
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PCT/JP2022/036033
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French (fr)
Japanese (ja)
Inventor
克彦 津野
克司 藤井
佳代 小池
智之 和田
Original Assignee
国立研究開発法人理化学研究所
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Priority to JP2023551559A priority Critical patent/JPWO2023054406A1/ja
Publication of WO2023054406A1 publication Critical patent/WO2023054406A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells

Definitions

  • the present disclosure relates to a DC bus control system.
  • Patent Document 1 discloses a DC bus control system for efficiently controlling power fluctuations in the DC bus caused by fluctuations in the input power supply and load.
  • the present disclosure provides a DC bus control system capable of increasing the capacity to charge from or discharge to the DC bus.
  • the present disclosure is a DC bus control system for controlling power fluctuations in a DC bus connecting between an input power source and a load, the primary stabilizer having a first charging/discharging element and a first power converter. at least one metastabilization device having a second charging/discharging element, charging element or discharging element and a second power converter; and an auxiliary device having a third charging/discharging element and a third power converter. and a device, wherein the first power converter obtains a bus voltage target value according to the storage amount index of the first charge/discharge element, and the voltage of the DC bus matches the bus voltage target value.
  • DC power is bidirectionally exchanged between the first charging/discharging element and the DC bus, and the second power converter includes the second charging/discharging element and the charging element.
  • a current target value is obtained according to a difference between a threshold value for charging or discharging of a discharging element and the voltage of the DC bus, and a current equal to the current target value is supplied to the second charging/discharging element, charging element, or discharging element.
  • a DC bus control system configured to receive and deliver power.
  • FIG. 1 is an overall configuration diagram of a DC bus control system according to this embodiment.
  • FIG. 2 is a configuration diagram showing another example of the metastabilization device in the DC bus control system according to this embodiment.
  • FIG. 3 is a block diagram showing a configuration example of a power converter in a photovoltaic power generation system.
  • FIG. 4 is a block diagram showing a configuration example of a power converter in the main stabilizer.
  • FIG. 5 is a block diagram showing a configuration example of a power converter in the auxiliary device.
  • FIG. 6 is a block diagram showing a configuration example of a power converter in the metastabilization device.
  • FIG. 7 is a block diagram showing a configuration example of a power converter in the metastabilization device.
  • FIG. 8 is a diagram for explaining the operation of the DC bus control system according to this embodiment.
  • FIG. 1 is an overall configuration diagram of a DC bus control system 1 according to this embodiment.
  • a DC bus control system 1 controls power fluctuations of a DC bus connecting between an input power source and a load.
  • a solar power generation system 10 and a wind power generation system 20, which are renewable energy power systems, are connected to the DC bus control system 1 as input power sources.
  • the solar power generation system 10 and the wind power generation system 20 are connected in parallel to the DC bus 70 of the DC bus control system 1 .
  • the photovoltaic power generation system 10 includes a solar cell 11 and a power converter 12 .
  • the wind power generation system 20 also includes a wind power generator 21 and a power converter 22 .
  • the input power supply connected to the DC bus control system 1 may be any power supply. If the input power supply is a renewable energy power supply system, it may be one that uses energy such as wave power or geothermal power other than the power supply system described above, hydropower (small hydropower) power generation, tidal power generation, tidal current power generation, A power supply system such as temperature difference power generation may be used. Also, a combination of the power supply systems described above may be used. Furthermore, the number of power supply systems connected in parallel with each other is not particularly limited.
  • a load 90 is also connected to the output of the DC bus control system 1 .
  • the load 90 includes, for example, household or business equipment, devices, and the like. Note that the load 90 also includes a case in which a plurality of home or business equipment, devices, or the like are arranged in parallel.
  • the load 90 may be a DC load such as a DC motor or a DC/AC (Direct Current/Alternate Current) converter that converts DC power to AC power and its AC load.
  • an AC power system may be connected to the DC bus 70 via a DC/AC converter.
  • the DC bus control system 1 may include an input power supply and may include a load. Also, the DC bus control system 1 may include both an input power source and a load.
  • the DC bus control system 1 includes a main stabilizer 30 and an auxiliary device 35 that assists the main stabilizer 30 .
  • the DC bus control system 1 also includes a metastabilizer 40 , a metastabilizer 50 , and a metastabilizer 60 .
  • the DC bus control system 1 includes a monitor/indicator 80 .
  • Each of the primary stabilizer 30 , the auxiliary device 35 , the metastabilizer 40 , the metastabilizer 50 and the metastabilizer 60 are connected to the DC bus 70 .
  • the main stabilizing device 30 includes a power storage device 31 and a power converter 32 .
  • the main stabilizer 30 sets a variable bus voltage target value within a predetermined allowable range centered on the reference bus voltage (reference voltage of the DC bus 70), and the output voltage on the DC bus 70 side becomes the bus voltage target value.
  • the power converter 32 is operated so that the charging and discharging of the power storage device 31 are controlled.
  • the auxiliary device 35 includes a power storage device 36 and a power converter 37.
  • Auxiliary device 35 charges/discharges power storage device 36 with current having a current value corresponding to the current value of the current charged/discharged in main stabilizing device 30 .
  • the power converter 37 of the auxiliary device 35 charges and discharges the power storage device 36 by operating the power converter 32 to flow a current having a current value corresponding to the current value of the current that charges and discharges the power storage device 31 .
  • Control Auxiliary device 35 charges and discharges power storage device 36 based on the charging and discharging current in main stabilizing device 30 , thereby apparently amplifying the power charged and discharged in main stabilizing device 30 .
  • the auxiliary device 35 operates according to the current value of the current charged and discharged in the main stabilizing device 30, for example, by a current value having a predetermined relationship with the current value of the current charged and discharged in the main stabilizing device 30.
  • the power storage device 36 is charged and discharged.
  • the meta-stabilization device 40 includes a power storage device 41 and a power converter 42 .
  • the meta-stabilization device 40 calculates input/output current target values based on the difference between the charge/discharge threshold and the voltage of the DC bus 70, and controls each power converter so that the input/output currents match the input/output current target values.
  • 42 is operated to control charging and discharging of the electric storage device 41 .
  • Each of the power storage device 31, the power storage device 36, and the power storage device 41 is, for example, a battery (secondary battery), an electric double layer capacitor, a capacitor, a flywheel, a redox flow battery, or the like.
  • Each of the power converter 32, the power converter 37, and the power converter 42 is, for example, an insulated DC/DC converter or chopper. It is possible.
  • the metastabilization device 50 includes a water electrolysis cell 51 and a power converter 52.
  • the power converter 52 performs DC/DC conversion so that the input current matches the input current target value calculated based on the difference between the charging threshold and the voltage of the DC bus 70, and the water electrolysis cell DC power is supplied to 51 (a kind of charging operation).
  • the water electrolysis cell 51 electrolyzes water to generate hydrogen gas and oxygen gas.
  • the metastabilization device 60 includes a fuel cell 61 and a power converter 62 .
  • the metastabilizer 60 supplies DC power generated by the electrochemical reaction of the fuel cell 61 to the DC bus 70 via the power converter 62 (a kind of discharge operation).
  • power converter 62 performs DC/DC conversion so that the output current matches the output current target value calculated based on the difference between the discharge threshold and the voltage of DC bus 70 .
  • the respective configurations of the meta-stabilization device 50 and the meta-stabilization device 60 described above are merely exemplary.
  • Alternatives to the water electrolysis cell 51 include, for example, electrochemically reducing carbon dioxide to produce C—H bonds (CH4, C2H4, etc.) and alcohol, or reducing nitrogen to produce ammonia. It may be a means to Alternatively to the fuel cell 61, for example, a fuel cell using alcohol or the like, or a power generation means that burns a chemical substance (hydrogen, CH, alcohol, ammonia, etc.) to rotate a turbine or the like may be used. .
  • FIG. 2 is a configuration diagram showing a meta-stabilization device 50A, which is another example of the meta-stabilization device in the DC bus control system 1 according to this embodiment.
  • the metastabilization device 50A includes a power converter 52 and a power converter 62, a water electrolysis cell 51, a fuel cell 61, and a hydrogen storage device 53.
  • Metastabilization device 50A has a unitary construction such that metastabilization device 50 and metastabilization device 60 previously described share hydrogen storage device 53 .
  • each of the power storage device 31, the power storage device 36, and the power storage device 41 is capable of absorbing (charging) and discharging (discharging) DC power.
  • the water electrolysis cell 51 can absorb (charge) the DC power by converting the DC power into gas and accumulating the gas.
  • the fuel cell 61 is capable of generating power by converting gas into DC power.
  • the hydrogen storage device 53 of FIG. 2 can also absorb (charge) and release (discharge) DC power by storing gas.
  • Each of power storage device 31, power storage device 36, and power storage device 41 constitutes a charging/discharging element.
  • the water electrolysis cell 51 constitutes a charging element.
  • the fuel cell 61 constitutes a discharge element. Note that the hydrogen storage device 53 constitutes a charge/discharge element.
  • the number of metastabilizers that the DC bus control system 1 has is not particularly limited.
  • the DC bus control system 1 may comprise at least one metastabilizer with charging/discharging, charging or discharging elements and a corresponding power converter. Further, when the DC bus control system 1 includes a plurality of metastabilizing devices, the number of metastabilizing devices having charge/discharge elements, the number of metastabilizing devices having charging elements, and the number of metastabilizing devices having discharging elements The number of devices may be appropriately combined and selected according to the state of use.
  • Each stabilizing device receives and receives DC power from DC bus 70. buffer. Also, each of the main stabilizer 30, the auxiliary device 35 and the meta-stabilizer 40 is a power buffer with charging and discharging functions.
  • Metastabilizer 50 is a power buffer with a charging function.
  • Metastabilizer 60 is a power buffer with a discharge function.
  • a required number of meta-stabilizers may be provided according to the parallel number of the power supply system and the required power of the load 90 .
  • the monitoring/indicating device 80 monitors each of the main stabilizing device 30, the auxiliary device 35, the metastabilizing device 40, the metastabilizing device 50, and the metastabilizing device 60 (hereinafter referred to as "main stabilizing device, etc.”). It collects status information and performs status monitoring and operation monitoring. State information includes, for example, voltage, current, temperature, and the like.
  • the monitoring/instruction device 80 generates an operation command and a charge/discharge threshold command based on the monitoring results of the main stabilizer and the like. Wired or wireless communication can be performed between the monitoring/instructing device 80 and the main stabilizing device or the like.
  • a solar power generation system 10 and a wind power generation system 20 are connected to a DC bus control system 1 according to this embodiment as input power sources.
  • the photovoltaic power generation system 10 and the wind power generation system 20 have a common function in that power generated using renewable energy is converted into DC power by the power converters 12 and 22, respectively, and supplied to the DC bus 70. have.
  • the photovoltaic power generation system 10 will be described as an example, and the description of the wind power generation system 20 will be omitted.
  • FIG. 3 is a block diagram showing a configuration example of the power converter 12 in the photovoltaic power generation system 10. As shown in FIG.
  • the power converter 12 includes a DC/DC converter 12A and a control circuit 12B.
  • the DC/DC converter 12A converts the DC output voltage of the solar cell 11 into a DC voltage of a predetermined magnitude by operating the semiconductor switching element, and outputs the DC voltage to the DC bus 70 .
  • the DC/DC converter 12A is configured by, for example, a boost chopper.
  • the control circuit 12B controls the DC/DC converter 12A.
  • the control circuit 12B includes a voltage detector 12a, a current detector 12b, an MPPT controller 12c, a voltage/current controller 12d, a drive circuit 12e, a voltage detector 12f, and a comparator 12g.
  • Voltage detector 12 a detects the output voltage of solar cell 11 .
  • Current detector 12 b detects the output current of solar cell 11 .
  • the MPPT control unit 12c performs maximum power point tracking control (MPPT: Maximum power point tracking).
  • MPPT Maximum power point tracking
  • the output voltage of the solar cell 11 detected by the voltage detector 12a and the output current of the solar cell 11 detected by the current detector 12b are input to the MPPT controller 12c.
  • the MPPT control section 12c searches for the maximum output point of the solar cell 11 by a hill-climbing method or the like, and outputs it to the voltage/current control section 12d.
  • the voltage/current control unit 12d generates drive pulses by pulse width modulation (PWM) control or the like based on the input from the MPPT control unit 12c.
  • the voltage/current control unit 12d outputs the generated drive pulse to the drive circuit 12e.
  • the drive circuit 12e turns on and off the semiconductor switching element of the DC/DC converter 12A based on the drive pulse output from the voltage/current controller 12d.
  • the voltage detector 12f detects the voltage of the DC bus 70.
  • the bus voltage detection value detected by the voltage detector 12f is input to the comparator 12g together with the bus voltage target value sent from the main stabilizing device 30, which will be described later.
  • the comparison unit 12g generates a control signal according to the deviation between the bus voltage detection value and the bus voltage target value, and outputs the control signal to the voltage/current control unit 12d.
  • the voltage/current control unit 12d calculates a drive pulse that matches the bus voltage detection value with the bus voltage target value based on the control signal output from the comparison unit 12g. For example, when the bus voltage detection value exceeds the bus voltage target value, the voltage/current control unit 12d performs a control operation to reduce the output voltage of the DC/DC conversion unit 12A (including stopping operation).
  • FIG. 4 is a block diagram showing a configuration example of the power converter 32 in the main stabilizer 30.
  • the power converter 32 includes a DC/DC converter 32A, a control circuit 32B, and a current detector 32C.
  • the DC/DC conversion unit 32A has a function of bidirectionally transferring DC power between the DC bus 70 and the power storage device 31 to control charging and discharging of the power storage device 31 .
  • the DC/DC converter 32A is configured by an insulated DC/DC converter, a chopper, or the like, which includes a semiconductor switching element.
  • the power storage device 31 includes a sensor 31s that detects voltage/current and temperature.
  • the control circuit 32B includes a voltage detector 32a, a bus voltage target value calculator 32b, a subtractor 32c, a charge/discharge controller 32d, and a drive circuit 32e.
  • the voltage detector 32a detects the voltage of the DC bus 70.
  • the bus voltage target value calculation unit 32 b calculates a bus voltage target value according to the power storage amount index of the power storage device 31 .
  • the bus voltage target value is calculated, for example, by measuring the charging/discharging current of the power storage device 31 to obtain an estimated power storage amount indicator, and calculating the estimated power storage amount indicator, the reference power storage amount indicator, and the reference bus voltage.
  • the bus voltage target value is set within the permissible range of the voltage of the DC bus 70 such that the larger the stored electricity amount indicator (for example, the charging rate), the higher the bus voltage target value, and the smaller the stored electricity amount indicator, the lower the bus voltage target value.
  • a charging rate (SOC: State of Charge) obtained by integrating the charge/discharge current of the power storage device 31 detected by the sensor 31s can be used as the power storage amount index of the power storage device 31 .
  • the subtractor 32c calculates the deviation between the bus voltage target value and the bus voltage detection value. Then, the subtractor 32c outputs the calculated deviation to the charge/discharge control section 32d.
  • the charge/discharge control unit 32d performs PWM control or the like so that the bus voltage detection value matches the bus voltage target value to generate a drive pulse.
  • the voltage/current, temperature, and charge/discharge threshold of the power storage device 31 are input to the charge/discharge control unit 32d.
  • the charge/discharge control unit 32d performs PWM control or the like so that the bus voltage detection value matches the bus voltage target value based on the input information such as the voltage/current, temperature, and charge/discharge threshold value of the power storage device 31. Generate drive pulses.
  • the drive circuit 32e turns on and off the semiconductor switching element of the DC/DC converter 32A according to the drive pulse generated by the charge/discharge controller 32d.
  • the DC/DC conversion unit 32A controls charging and discharging of the power storage device 31 as described above so that the bus voltage detection value matches the bus voltage target value.
  • the current detector 32C detects the current value of the current that charges and discharges the power storage device 31 .
  • the current detector 32 ⁇ /b>C outputs the detected current value (current detection value) to the power converter 37 of the auxiliary device 35 .
  • the charge/discharge threshold of the power storage device 31 may be set by the control circuit 32B itself, or may be received as a command from the monitoring/instruction device 80.
  • FIG. 5 is a block diagram showing a configuration example of the power converter 37 in the auxiliary device 35.
  • the power converter 37 includes a DC/DC converter 37A, a control circuit 37B, and a current detector 37C.
  • the DC/DC conversion unit 37A has a function of bidirectionally transferring DC power between the DC bus 70 and the power storage device 31 to control charging and discharging of the power storage device 31 .
  • the DC/DC converter 37A is configured by an insulated DC/DC converter, a chopper, or the like, which includes a semiconductor switching element.
  • the power storage device 36 includes a sensor 36s that detects voltage/current and temperature.
  • the control circuit 37B includes an amplifier 37a, a subtractor 37c, a charge/discharge control section 37d, and a drive circuit 37e.
  • Current detector 37 ⁇ /b>C measures the current value of the current that charges and discharges power storage device 36 .
  • the current detector 32 ⁇ /b>C outputs the measured current value (current detection value) to the power converter 37 of the auxiliary device 35 .
  • the amplifier 37a amplifies the current detection value detected by the current detector 37C with a predetermined amplification factor.
  • the subtractor 37c then calculates the deviation between the detected current value input from the current detector 32C of the main stabilizer 30 and the detected current value output from the amplifier 37a. Then, the subtractor 37c outputs the calculated deviation to the charge/discharge control section 37d.
  • the charge/discharge control unit 37d performs PWM control or the like so that the current detection value output from the amplifier 37a matches the current detection value input from the current detector 32C of the main stabilizer 30 to generate a drive pulse.
  • the drive circuit 37e turns on and off the semiconductor switching element of the DC/DC converter 37A according to the drive pulse generated by the charge/discharge controller 37d.
  • the DC/DC conversion unit 37A controls charging and discharging of the power storage device 36 as described above, and matches the current detection value output from the amplifier 37a with the current detection value input from the current detector 32C of the main stabilizing device 30.
  • power converter 37 charges and discharges power storage device 36 with a current value corresponding to the current value of the current charged and discharged in main stabilizer 30. discharge control.
  • Current value Im is the current value of the current that charges and discharges in the main stabilizer 30
  • current value Is is the current value of the current that the power converter 37 charges and discharges to the storage device 36
  • F is a function that monotonously increases with respect to the variable x.
  • the control circuit 37B charges and discharges to the current value Is according to the current value Im so as to satisfy the following equation.
  • the sign of each of the current value Im and the current value Is for example, the charging current is positive.
  • the function F(x) may be a linear function or a nonlinear function as long as it monotonically increases with respect to the variable x.
  • the current value Is may match the current value Im, or the current value Is may be proportional to the current value Im.
  • the ratio (slope) of the amount of increase in the current value Is to the amount of increase in the current value Im is not limited to a constant value. good too.
  • auxiliary devices 35 is not limited to one.
  • the DC bus control system 1 may be provided with a plurality of auxiliary devices 35 .
  • main stabilizers 30 control the bus voltage of the DC bus 70. There is a possibility that the control of the voltage will compete with the main stabilizers 30 and the system will become unstable.
  • the bus voltage of the DC bus 70 is controlled by one main stabilizer 30, and the power storage device 36 of the auxiliary device 35 is charged/discharged. By supplying a charging/discharging current corresponding to the current value of the current to be applied, the charging/discharging capacity can be increased. Further, according to the DC bus control system 1 according to the present embodiment, the bus voltage of the DC bus 70 is stably controlled by performing the control of the bus voltage of the DC bus 70 by one main stabilizer 30. can.
  • FIG. 6 is a block diagram showing a configuration example of the power converter 42 in the metastabilization device 40.
  • the power converter 42 includes a DC/DC converter 42A and a control circuit 42B.
  • Power converter 42 has the same function as power converter 32 in main stabilizing device 30 in that DC power is bidirectionally exchanged between DC bus 70 and power storage device 41 .
  • the power storage device 41 includes a sensor 41s that detects voltage/current and temperature.
  • the control circuit 42B includes a voltage detector 42a, a comparator 42b, a subtractor 42c, a charge/discharge controller 42d, and a drive circuit 42e.
  • the power converter 42 differs from the power converter 32 in the main stabilizer 30 in the following points.
  • the charge/discharge control unit 42d of the control circuit 42B calculates the input/output current target value based on the deviation between the charge/discharge threshold value and the bus voltage detection value.
  • the charge/discharge control unit 42d further performs charge/discharge control for the power storage device 41 so that the input/output current of the DC/DC conversion unit 42A matches the input/output current target value.
  • the charging/discharging threshold may be a threshold (charging threshold and discharging threshold) relating to charging/discharging of the power storage device 41 , and the input/output current target value may be determined according to the difference between the charging/discharging threshold and the voltage of the DC bus 70 .
  • the comparison unit 42b provided in the control circuit 42B compares the charging/discharging threshold value of the power storage device 41 with the bus voltage detection value, and outputs a charging command or a It outputs a discharge command to control the operation of the charge/discharge controller 42d.
  • the charge/discharge threshold may be set by the control circuit 42B itself, or may be received as a command from the monitor/instruction device 80 .
  • FIG. 7 is a block diagram showing a configuration example of the power converter 52 in the metastabilization device 50. As shown in FIG.
  • the power converter 52 includes a DC/DC converter 52A and a control circuit 52B.
  • the DC/DC converter 52A has a function of converting the DC power of the DC bus 70 into a predetermined magnitude and supplying it to the water electrolysis cell 51.
  • the DC/DC converter 52A is configured by an insulated DC/DC converter, a chopper, or the like, which includes a semiconductor switching element.
  • the water electrolysis cell 51 electrolyzes water using the DC power supplied from the DC/DC converter 52A.
  • the hydrogen gas generated by the water electrolysis cell 51 is stored in an external storage device (not shown).
  • the water electrolysis cell 51 performs an operation of converting DC power into hydrogen gas and storing it, in other words, performs a kind of charging operation.
  • a control circuit 52B that controls the DC/DC converter 52A has the same configuration as the control circuit 42B.
  • the control circuit 52B includes a voltage detector 52a, a comparator 52b, a subtractor 52c, a charge controller 52d, and a drive circuit 52e.
  • the voltage of the DC bus 70 is detected by the voltage detector 52a. Also, the deviation between the charge threshold and the bus voltage detection value is calculated by the subtractor 52c. Then, the deviation between the charge threshold value and the bus voltage detection value is input to the charge controller 52d. Also, the bus voltage detection value is input to the comparison unit 52b together with the charge threshold. The comparison unit 52b outputs a charge command to the charge control unit 52d when the bus voltage detection value exceeds the charge threshold.
  • the charge threshold corresponds to the starting voltage of electrolysis by the water electrolysis cell 51 . That is, the charging threshold is a threshold for charging the water electrolysis cell 51 .
  • the charge control unit 52d calculates the input/output current target value based on the deviation between the charge threshold input from the subtractor 52c and the bus voltage detection value. Then, the charge control unit 52d generates a drive pulse as a charge command so that the input/output current of the DC/DC conversion unit 52A matches the input/output current target value, and outputs the drive pulse to the drive circuit 52e.
  • the drive circuit 52e turns on and off the semiconductor switching element of the DC/DC converter 52A according to the drive pulse generated by the charge controller 52d.
  • the DC/DC converter 52A supplies DC power to the water electrolysis cell 51 to electrolyze water.
  • the DC/DC converter 52A operates to match the input/output current with the input/output current target value while controlling the DC power supplied to the water electrolysis cell 51 by the above operation.
  • the power generation operation by the fuel cell 61 is considered as the discharge operation, and the water electrolysis cell 51 and the charge threshold and charge control unit 52d of the metastabilization device 50 are the fuel cell 61 and the discharge threshold and discharge control unit, respectively. should be replaced with .
  • the discharge threshold corresponds to the starting voltage for power generation by the fuel cell 61 .
  • the quasi-stabilization device 60 outputs a drive pulse corresponding to a discharge command to the discharge control unit to operate the DC/DC conversion unit when the bus voltage detection value falls below the discharge threshold.
  • the meta-stabilizer 60 supplies power generated by the fuel cell 61 to the DC bus 70 via the DC/DC converter.
  • the DC/DC converter operates to match the input/output current with the input/output current target value while controlling the power generated by the fuel cell 61 through the above operation.
  • Each of the water electrolysis cell 51 and the fuel cell 61 is also provided with a sensor for detecting voltage, current, temperature, etc., and these detected values are input to the charge control section 52d and the discharge control section. Illustration of the sensor is omitted.
  • the charge threshold and the discharge threshold may be set by each control circuit themselves, or may be received from the monitor/instruction device 80 as a command.
  • the configuration and operation of the control circuit 52B are merely examples and do not limit the technical scope of the present invention, and it goes without saying that configurations different from these may be adopted.
  • FIG. 8 shows the charge/discharge power of the electricity storage device 41 of the metastabilization device 40 according to the voltage of the DC bus 70, the input power of the water electrolysis cell 51 of the metastabilization device 50, and the fuel of the metastabilization device 60.
  • 4A and 4B are conceptual diagrams schematically showing the output power of the battery 61.
  • FIG. The horizontal width of the triangular symbol in FIG. 8 indicates the magnitude of each power, and the wider the width, the larger the power value.
  • FIG. 8 illustrates a case where the input power source is a renewable energy power system
  • the renewable energy power system is, for example, the solar power generation system 10 and the wind power generation system 20 in FIG. Charge/discharge of each part according to the voltage of the DC bus 70 to which the power generated by the solar power generation system 10 and the wind power generation system 20 is supplied and the charge/discharge threshold of the power storage device 41, the water electrolysis cell 51, and the fuel cell 61. movement is controlled.
  • the charging power supplied to the power storage device 41 increases as the bus voltage is higher than the charging threshold of the power storage device 41 .
  • the lower the bus voltage is below the discharge threshold of power storage device 41, the greater the discharge power discharged from power storage device 41 becomes.
  • the higher the bus voltage is higher than the charging threshold of the water electrolysis cell 51, the greater the charge power supplied to the water electrolysis cell 51 becomes.
  • the lower the bus voltage is below the discharge threshold of the fuel cell 61, the greater the discharge power generated from the fuel cell 61 becomes.
  • the charge threshold and discharge threshold are set lower than (a) according to the reference bus voltage, and in (c) the charge threshold and discharge threshold are set higher than (a). indicate the case.
  • a similar threshold setting change operation is also possible for the charging threshold of the water electrolysis cell 51 and the discharging threshold of the fuel cell 61 .
  • the DC bus 70, the metastabilization device 40, the metastabilization device 50, and the metastabilization device 50 are controlled.
  • the DC power sent to and received from device 60 can be individually adjusted. In other words, it is possible to finely control the operation of each power buffer.
  • the charge threshold and discharge threshold may be changed based on a command from the monitoring/instruction device 80, or may be changed by the power converter 42, the power converter 52, and the power converter 62 by themselves.
  • the power storage device 31 is an example of a first charging/discharging element
  • the power converter 32 is an example of a first power converter
  • the power storage device 41 is an example of a second charging/discharging element
  • a power converter 42 and a power converter.
  • Either 52 or power converter 62 is an example of a second power converter
  • power storage device 36 is an example of a third charge/discharge element
  • power converter 37 is an example of a third power converter.
  • ⁇ Stability of DC bus control system 1 The stability of the DC bus control system 1 according to this embodiment will be described.
  • the main stabilizing device 30 and the auxiliary device 35 are collectively referred to as the main stabilizing device (MVC: Main Voltage Controller), the metastabilizing device 40, the metastabilizing device 50, and the metastabilizing device 60. is called a meta-stabilizer (SVC: Sub Voltage Controller).
  • the main stabilizer controls the bus voltage VB .
  • the bus voltage VB is determined according to Equation 1 by the main stabilizer. That is, the DC/DC converter of the main stabilizer is a bi-directional converter with a constant voltage output.
  • C MVC is the capacity of the storage device in the main stabilizer
  • I MVC is the current flowing through the storage device in the main stabilizer (charge current is assumed to be positive)
  • V B0 is the bias voltage
  • Q MVC is the main stabilizer. is the amount of electric charge charged in the electricity storage device in the conversion device.
  • the main stabilizer shifts to constant current control with the maximum supply/absorption power of the storage device while setting VB as the control target voltage.
  • constant current control since all devices including the metastabilizer have constant current, the bus voltage is automatically determined so that the metastabilizer absorbs and discharges the surplus/shortage. Therefore, the bus voltage is regulated to VB and the maximum supply power is supplied from the main stabilizer at constant current. That is, the DC bus control system 1 can control power that exceeds the power that the main stabilizer can handle. However, if the power supplied exceeds the power that the main stabilizer can handle, the absolute value of the amount of charge charged in the storage device in the main stabilizer increases, and the stability of the normal metastabilizer increases. out of control range.
  • the DC bus control system 1 does not stop even when power input/output exceeds the handling capability of the main stabilizer.
  • the response of the DC bus control system 1 is not the usual linear response.
  • the recovery time of the DC bus control system 1 is the time for discharging and absorbing the charges integrated during this period. The recovery time is roughly as long as the overload time.
  • a metastabilizer generates and absorbs a current (or as may be defined in terms of power) determined by the bus voltage. It has a constant current source/constant current load interface in order to supply and receive power regardless of the value of the bus voltage VB .
  • the generated and absorbed current I SVC is generally represented by Equation 2.
  • each of the two-way device capable of generation/absorption, the device capable of only generation, and the device capable of only absorption can be expressed as different functional systems of the function I SVC ( ).
  • the sign is positive in the direction of power absorption from the DC bus. Note that the sign may be defined in the opposite way.
  • External devices such as power consumers and generator devices, connect to the DC bus as current mode (eg, constant current source).
  • a total current consumption I ext of the external device is expressed as in Equation 3. Note that the sign is positive for power consumption.
  • the current I MVC in Equation 1 may be the actual charge/discharge current of the power storage device or the current on the DC bus side, if the conversion efficiency and the bias current are taken into consideration.
  • the current IMVC is the current of the storage device.
  • Equation 4 shows the power balance on the DC bus. Note that B is an offset current.
  • the DC bus control system 1 exhibits a first-order lag system response.
  • the DC bus control system 1 can operate stably without oscillation.
  • the charging efficiency of the storage device can be estimated from the terminal voltage. However, since the terminal voltage depends on the charging/discharging current, it is necessary to set the charging/discharging current to zero and measure it. Using the fact that zero charge/discharge current is automatically achieved when the external device is stable, we can incorporate control of charge efficiency with the following equation.
  • V SoC indicates the terminal voltage of the storage device
  • V T indicates the control target value of the storage device terminal voltage.
  • the integration of the second term is meant to be performed only if the absolute value of I MVC is less than the threshold I th .
  • the threshold Ith is a threshold current value set as an empirical value. The above formula is actually calculated and controlled by discretization.
  • DC bus control system 10 solar power generation system 20 wind power generation system 30 main stabilizer 36 power storage devices 40, 50, 50A, 60 meta-stabilization devices 31, 36, 41, 46 power storage device 51 water electrolysis cell 61 fuel cell 32 , 37, 42, 52, 62 power converter 70 DC bus 80 monitor/indicator 90 load

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Abstract

This DC bus control system controls the power fluctuation of a DC bus connecting an input power source and a load, the system including: a main stabilizer having a first charging/discharging element and a first power converter; at least one sub-stabilizer having a second charging/discharging element, a charging element or a discharging element, and a second power converter; and an auxiliary device having a third charging/discharging element and a third power converter. The first power converter is configured so that the DC bus voltage matches a bus voltage target value; the first power converter detects the current value of a current flowing in the first charging/discharging element; and the third power converter is configured so as to give and receive DC power between the third charging/discharging element and the DC bus using a charging/discharging current having a current value corresponding to said current value.

Description

直流バス制御システムDC bus control system
　本開示は、直流バス制御システムに関する。 The present disclosure relates to a DC bus control system.
　近年、化石エネルギーや原子力エネルギーの代替電源として、太陽光や風力、波力等の再生可能エネルギーを利用した電源システムが注目されている。また、太陽光や風力、波力等の再生可能エネルギーを利用した電源システムの一部は既に実用化されている。 In recent years, attention has been focused on power systems that use renewable energy sources such as sunlight, wind power, and wave power as alternative power sources for fossil and nuclear energy. In addition, some power supply systems using renewable energy such as sunlight, wind power, and wave power have already been put into practical use.
　太陽光や風力、波力等の再生可能エネルギーを利用した電源システムは、天候や季節、立地等によって発電電力が大きく変動する。したがって、電源システムが接続される直流バスの電圧を所定の許容範囲に維持するには、太陽電池や風力発電機等の電源を、入力範囲が広く大容量の電力変換器を介して直流バスに接続することが望ましい。しかしながら、大容量の電力変換器を介して直流バスに接続する場合には、電力変換器の大容量化によってシステム全体の大型化や複雑化、高コスト化を招くことになる。 Power systems that use renewable energy such as sunlight, wind power, and wave power fluctuate greatly depending on the weather, season, location, and other factors. Therefore, in order to maintain the voltage of the DC bus to which the power supply system is connected within a predetermined tolerance, power sources such as solar cells and wind turbines must be connected to the DC bus through a wide input range, high capacity power converter. preferably connected. However, when connecting to a DC bus via a large-capacity power converter, the increased capacity of the power converter results in an increase in the size, complexity, and cost of the entire system.
　特許文献１には、入力電源や負荷の変動に起因して生ずる直流バスの電力変動を効率的に制御するための直流バス制御システムが開示されている。 Patent Document 1 discloses a DC bus control system for efficiently controlling power fluctuations in the DC bus caused by fluctuations in the input power supply and load.
国際公開第２０１９／１０３０５９号WO2019/103059
　特許文献１に開示の制御システムにおいて、主安定化装置の容量を大きくすることが望まれている。 In the control system disclosed in Patent Document 1, it is desired to increase the capacity of the main stabilizer.
　本開示は、直流バスからの充電又は直流バスへの放電する容量を増やすことが可能な直流バス制御システムを提供する。 The present disclosure provides a DC bus control system capable of increasing the capacity to charge from or discharge to the DC bus.
　本開示は、入力電源と負荷との間を接続する直流バスの電力変動を制御する直流バス制御システムであって、第１の充放電要素と第１の電力変換器とを有する主安定化装置と、第２の充放電要素、充電要素又は放電要素と第２の電力変換器とを有する少なくとも１つの準安定化装置と、第３の充放電要素と第３の電力変換器とを有する補助装置と、を含み、前記第１の電力変換器は、前記第１の充放電要素の蓄電量指標に応じたバス電圧目標値を求め、前記バス電圧目標値に前記直流バスの前記電圧が一致するように、前記第１の充放電要素と前記直流バスとの間で直流電力を双方向に授受するよう構成され、前記第２の電力変換器は、前記第２の充放電要素、充電要素又は放電要素の充電又は放電に関する閾値と前記直流バスの前記電圧との差分に応じて電流目標値を求め、前記電流目標値に等しい電流が前記第２の充放電要素、充電要素又は放電要素に流れるように、前記第２の充放電要素、充電要素又は放電要素と前記直流バスとの間で直流電力を授受するよう構成され、前記第１の電力変換器は、前記第１の充放電要素に流れる電流の電流値を検出し、前記第３の電力変換器は、前記電流値に応じた電流値を有する充放電電流により、前記第３の充放電要素と前記直流バスとの間で直流電力を授受するよう構成される、ことを特徴とする直流バス制御システムである。 The present disclosure is a DC bus control system for controlling power fluctuations in a DC bus connecting between an input power source and a load, the primary stabilizer having a first charging/discharging element and a first power converter. at least one metastabilization device having a second charging/discharging element, charging element or discharging element and a second power converter; and an auxiliary device having a third charging/discharging element and a third power converter. and a device, wherein the first power converter obtains a bus voltage target value according to the storage amount index of the first charge/discharge element, and the voltage of the DC bus matches the bus voltage target value. DC power is bidirectionally exchanged between the first charging/discharging element and the DC bus, and the second power converter includes the second charging/discharging element and the charging element. Alternatively, a current target value is obtained according to a difference between a threshold value for charging or discharging of a discharging element and the voltage of the DC bus, and a current equal to the current target value is supplied to the second charging/discharging element, charging element, or discharging element. configured to flow DC power between the second charging/discharging element, charging element or discharging element and the DC bus, the first power converter configured to flow between the second charging/discharging element, charging element or discharging element and the DC bus; and the third power converter detects a current value of a current flowing through the DC bus between the third charging/discharging element and the DC bus by a charging/discharging current having a current value corresponding to the current value. A DC bus control system configured to receive and deliver power.
　本開示の直流バス制御システムによれば、直流バスからの充電又は直流バスへの放電する容量を増やすことができる。 According to the DC bus control system of the present disclosure, it is possible to increase the capacity to be charged from or discharged to the DC bus.
図１は、本実施形態に係る直流バス制御システムの全体構成図である。FIG. 1 is an overall configuration diagram of a DC bus control system according to this embodiment. 図２は、本実施形態に係る直流バス制御システムにおける準安定化装置の他の例を示す構成図である。FIG. 2 is a configuration diagram showing another example of the metastabilization device in the DC bus control system according to this embodiment. 図３は、太陽光発電システムにおける電力変換器の一構成例を示すブロック図である。FIG. 3 is a block diagram showing a configuration example of a power converter in a photovoltaic power generation system. 図４は、主安定化装置における電力変換器の一構成例を示すブロック図である。FIG. 4 is a block diagram showing a configuration example of a power converter in the main stabilizer. 図５は、補助装置における電力変換器の一構成例を示すブロック図である。FIG. 5 is a block diagram showing a configuration example of a power converter in the auxiliary device. 図６は、準安定化装置における電力変換器の一構成例を示すブロック図である。FIG. 6 is a block diagram showing a configuration example of a power converter in the metastabilization device. 図７は、準安定化装置内の電力変換器の一構成例を示すブロック図である。FIG. 7 is a block diagram showing a configuration example of a power converter in the metastabilization device. 図８は、本実施形態に係る直流バス制御システムの動作を説明する図である。FIG. 8 is a diagram for explaining the operation of the DC bus control system according to this embodiment.
　以下、図面を参照して、本実施形態に係る直流バス制御システムについて詳細を説明する。なお、国際公開第２０１９／１０３０５９号の内容は、参照することにより、その全体が本明細書に引用される。 The details of the DC bus control system according to the present embodiment will be described below with reference to the drawings. The contents of WO2019/103059 are hereby incorporated by reference in their entirety.
　図１は、本実施形態に係る直流バス制御システム１の全体構成図である。直流バス制御システム１は、入力電源と負荷との間を接続する直流バスの電力変動を制御する。直流バス制御システム１には、入力電源として、再生可能エネルギー電源システムである太陽光発電システム１０及び風力発電システム２０が接続される。太陽光発電システム１０及び風力発電システム２０は、並列に直流バス制御システム１の直流バス７０に接続される。太陽光発電システム１０は太陽電池１１及び電力変換器１２を含む。また、風力発電システム２０は風力発電機２１及び電力変換器２２を含む。 FIG. 1 is an overall configuration diagram of a DC bus control system 1 according to this embodiment. A DC bus control system 1 controls power fluctuations of a DC bus connecting between an input power source and a load. A solar power generation system 10 and a wind power generation system 20, which are renewable energy power systems, are connected to the DC bus control system 1 as input power sources. The solar power generation system 10 and the wind power generation system 20 are connected in parallel to the DC bus 70 of the DC bus control system 1 . The photovoltaic power generation system 10 includes a solar cell 11 and a power converter 12 . The wind power generation system 20 also includes a wind power generator 21 and a power converter 22 .
　なお、直流バス制御システム１に接続される入力電源は任意の電源であってよい。入力電源が再生可能エネルギー電源システムである場合、上述した電源システム以外に波力や地熱等のエネルギーを利用したものであってもよいし、水力（小水力）発電、潮力発電、潮流発電、温度差発電等の電源システムであってもよい。また、上述した電源システムの組み合わせであってもよい。さらに、互いに並列に接続される電源システムの数は特に限定されない。 The input power supply connected to the DC bus control system 1 may be any power supply. If the input power supply is a renewable energy power supply system, it may be one that uses energy such as wave power or geothermal power other than the power supply system described above, hydropower (small hydropower) power generation, tidal power generation, tidal current power generation, A power supply system such as temperature difference power generation may be used. Also, a combination of the power supply systems described above may be used. Furthermore, the number of power supply systems connected in parallel with each other is not particularly limited.
　また、直流バス制御システム１には、出力に、負荷９０が接続される。負荷９０には、例えば、家庭用又は事業用の機器、装置等が含まれる。なお、負荷９０には、家庭用又は事業用の機器、装置等が並列に複数配置される場合も含まれる。また、負荷９０は、直流電動機等の直流負荷又は直流電力を交流電力に変換するＤＣ／ＡＣ（Ｄｉｒｅｃｔ　Ｃｕｒｒｅｎｔ／Ａｌｔｅｒｎａｔｅ　Ｃｕｒｒｅｎｔ）変換器及びその交流負荷であってもよい。また、負荷９０として、直流バス７０にＤＣ／ＡＣ変換器を介して交流電力系統が接続されていてもよい。 A load 90 is also connected to the output of the DC bus control system 1 . The load 90 includes, for example, household or business equipment, devices, and the like. Note that the load 90 also includes a case in which a plurality of home or business equipment, devices, or the like are arranged in parallel. Also, the load 90 may be a DC load such as a DC motor or a DC/AC (Direct Current/Alternate Current) converter that converts DC power to AC power and its AC load. Alternatively, as the load 90, an AC power system may be connected to the DC bus 70 via a DC/AC converter.
　なお、直流バス制御システム１は、入力電源を含んでもよいし、負荷を含んでもよい。また、直流バス制御システム１は、入力電源及び負荷の両方を含んでもよい。 It should be noted that the DC bus control system 1 may include an input power supply and may include a load. Also, the DC bus control system 1 may include both an input power source and a load.
　直流バス制御システム１は、主安定化装置３０と、主安定化装置３０を補助する補助装置３５と、を備える。また、直流バス制御システム１は、準安定化装置４０と、準安定化装置５０と、準安定化装置６０と、を備える。さらに、直流バス制御システム１は、監視・指示装置８０を備える。 The DC bus control system 1 includes a main stabilizer 30 and an auxiliary device 35 that assists the main stabilizer 30 . The DC bus control system 1 also includes a metastabilizer 40 , a metastabilizer 50 , and a metastabilizer 60 . Furthermore, the DC bus control system 1 includes a monitor/indicator 80 .
　主安定化装置３０、補助装置３５、準安定化装置４０、準安定化装置５０及び準安定化装置６０のそれぞれは、直流バス７０に接続される。 Each of the primary stabilizer 30 , the auxiliary device 35 , the metastabilizer 40 , the metastabilizer 50 and the metastabilizer 60 are connected to the DC bus 70 .
　主安定化装置３０は、蓄電装置３１と、電力変換器３２と、を備える。主安定化装置３０は、基準バス電圧（直流バス７０の基準電圧）を中心とした所定の許容範囲内で可変のバス電圧目標値を設定し、直流バス７０側の出力電圧がバス電圧目標値に一致するように電力変換器３２を動作させて蓄電装置３１を充放電制御する。 The main stabilizing device 30 includes a power storage device 31 and a power converter 32 . The main stabilizer 30 sets a variable bus voltage target value within a predetermined allowable range centered on the reference bus voltage (reference voltage of the DC bus 70), and the output voltage on the DC bus 70 side becomes the bus voltage target value. The power converter 32 is operated so that the charging and discharging of the power storage device 31 are controlled.
　補助装置３５は、蓄電装置３６と、電力変換器３７と、を備える。補助装置３５は、主安定化装置３０において充放電する電流の電流値に応じた電流値の電流により蓄電装置３６を充放電する。補助装置３５の電力変換器３７は、電力変換器３２が蓄電装置３１に充放電する電流の電流値に応じた電流値の電流を蓄電装置３６に流すように動作させて蓄電装置３６を充放電制御する。補助装置３５は、主安定化装置３０における充放電電流に基づいて、蓄電装置３６に充放電することにより、主安定化装置３０における充放電する電力を見かけ上増幅する。 The auxiliary device 35 includes a power storage device 36 and a power converter 37. Auxiliary device 35 charges/discharges power storage device 36 with current having a current value corresponding to the current value of the current charged/discharged in main stabilizing device 30 . The power converter 37 of the auxiliary device 35 charges and discharges the power storage device 36 by operating the power converter 32 to flow a current having a current value corresponding to the current value of the current that charges and discharges the power storage device 31 . Control. Auxiliary device 35 charges and discharges power storage device 36 based on the charging and discharging current in main stabilizing device 30 , thereby apparently amplifying the power charged and discharged in main stabilizing device 30 .
　補助装置３５は、主安定化装置３０において充放電する電流の電流値に応じて、例えば、主安定化装置３０において充放電する電流の電流値に対して所定の関係を有する電流値の電流により蓄電装置３６を充放電する。 The auxiliary device 35 operates according to the current value of the current charged and discharged in the main stabilizing device 30, for example, by a current value having a predetermined relationship with the current value of the current charged and discharged in the main stabilizing device 30. The power storage device 36 is charged and discharged.
　準安定化装置４０は、蓄電装置４１と、電力変換器４２と、を備える。準安定化装置４０は、充放電閾値と直流バス７０の電圧との差分に基づいて入出力電流目標値を演算し、入出力電流が入出力電流目標値に一致するようにそれぞれの電力変換器４２を動作させて蓄電装置４１を充放電制御する。 The meta-stabilization device 40 includes a power storage device 41 and a power converter 42 . The meta-stabilization device 40 calculates input/output current target values based on the difference between the charge/discharge threshold and the voltage of the DC bus 70, and controls each power converter so that the input/output currents match the input/output current target values. 42 is operated to control charging and discharging of the electric storage device 41 .
　蓄電装置３１、蓄電装置３６及び蓄電装置４１のそれぞれは、例えば、バッテリー（二次電池）、電気二重層コンデンサ、キャパシタ、フライホイール又はレドックスフロー電池等である。また、電力変換器３２、電力変換器３７及び電力変換器４２のそれぞれは、例えば絶縁型のＤＣ／ＤＣコンバータ又はチョッパ等であり、図１に記載した矢印に示すごとく双方向に直流電力を授受可能である。 Each of the power storage device 31, the power storage device 36, and the power storage device 41 is, for example, a battery (secondary battery), an electric double layer capacitor, a capacitor, a flywheel, a redox flow battery, or the like. Each of the power converter 32, the power converter 37, and the power converter 42 is, for example, an insulated DC/DC converter or chopper. It is possible.
　準安定化装置５０は、水電解セル５１と、電力変換器５２と、を備える。準安定化装置５０は、充電閾値と直流バス７０の電圧との差分に基づいて演算した入力電流目標値に入力電流が一致するように電力変換器５２がＤＣ／ＤＣ変換を行って水電解セル５１に直流電力を供給する（一種の充電動作）。水電解セル５１は、水を電気分解して水素ガス及び酸素ガスを生成する。 The metastabilization device 50 includes a water electrolysis cell 51 and a power converter 52. In the meta-stabilization device 50, the power converter 52 performs DC/DC conversion so that the input current matches the input current target value calculated based on the difference between the charging threshold and the voltage of the DC bus 70, and the water electrolysis cell DC power is supplied to 51 (a kind of charging operation). The water electrolysis cell 51 electrolyzes water to generate hydrogen gas and oxygen gas.
　準安定化装置６０は、燃料電池６１と、電力変換器６２と、を備える。準安定化装置６０は、燃料電池６１の電気化学反応により発生した直流電力を、電力変換器６２を介して直流バス７０に供給する（一種の放電動作）。準安定化装置６０は、放電閾値と直流バス７０の電圧との差分に基づいて演算した出力電流目標値に出力電流が一致するように電力変換器６２がＤＣ／ＤＣ変換を行う。 The metastabilization device 60 includes a fuel cell 61 and a power converter 62 . The metastabilizer 60 supplies DC power generated by the electrochemical reaction of the fuel cell 61 to the DC bus 70 via the power converter 62 (a kind of discharge operation). In meta-stabilization device 60 , power converter 62 performs DC/DC conversion so that the output current matches the output current target value calculated based on the difference between the discharge threshold and the voltage of DC bus 70 .
　なお、上述した準安定化装置５０及び準安定化装置６０のそれぞれの構成はあくまで例示的なものである。水電解セル５１に代わるものとしては、例えば、電気化学的に、二酸化炭素還元を行ってＣ－Ｈ系の結合（ＣＨ４、Ｃ２Ｈ４等）やアルコールを製造する手段又は窒素を還元してアンモニアを製造する手段でもよい。また、燃料電池６１に代わるものとしては、例えば、アルコール等を用いた燃料電池や、化学物質（水素やＣ－Ｈ系、アルコール、アンモニア等）を燃焼してタービン等を回転させる発電手段でもよい。 It should be noted that the respective configurations of the meta-stabilization device 50 and the meta-stabilization device 60 described above are merely exemplary. Alternatives to the water electrolysis cell 51 include, for example, electrochemically reducing carbon dioxide to produce C—H bonds (CH4, C2H4, etc.) and alcohol, or reducing nitrogen to produce ammonia. It may be a means to Alternatively to the fuel cell 61, for example, a fuel cell using alcohol or the like, or a power generation means that burns a chemical substance (hydrogen, CH, alcohol, ammonia, etc.) to rotate a turbine or the like may be used. .
　図２は、本実施形態に係る直流バス制御システム１における準安定化装置の他の例である準安定化装置５０Ａを示す構成図である。準安定化装置５０Ａは、電力変換器５２及び電力変換器６２と、水電解セル５１と、燃料電池６１と、水素貯蔵装置５３と、を備える。準安定化装置５０Ａは、前述した準安定化装置５０及び準安定化装置６０が水素貯蔵装置５３を共有するような一体構造を有する。 FIG. 2 is a configuration diagram showing a meta-stabilization device 50A, which is another example of the meta-stabilization device in the DC bus control system 1 according to this embodiment. The metastabilization device 50A includes a power converter 52 and a power converter 62, a water electrolysis cell 51, a fuel cell 61, and a hydrogen storage device 53. Metastabilization device 50A has a unitary construction such that metastabilization device 50 and metastabilization device 60 previously described share hydrogen storage device 53 .
　図１において、蓄電装置３１、蓄電装置３６及び蓄電装置４１のそれぞれは直流電力の吸収（充電）及び放出（放電）が可能である。また、水電解セル５１は直流電力をガスに変換して蓄積して直流電力の吸収（充電）が可能である。燃料電池６１はガスを直流電力に変換する発電動作が可能である。なお、図２の水素貯蔵装置５３についても、ガスを貯蔵することにより直流電力の吸収（充電）及び放出（放電）が可能である。蓄電装置３１、蓄電装置３６及び蓄電装置４１のそれぞれは充放電要素を構成する。水電解セル５１は充電要素を構成する。また、燃料電池６１は放電要素を構成する。なお、水素貯蔵装置５３は、充放電要素を構成する。 In FIG. 1, each of the power storage device 31, the power storage device 36, and the power storage device 41 is capable of absorbing (charging) and discharging (discharging) DC power. In addition, the water electrolysis cell 51 can absorb (charge) the DC power by converting the DC power into gas and accumulating the gas. The fuel cell 61 is capable of generating power by converting gas into DC power. The hydrogen storage device 53 of FIG. 2 can also absorb (charge) and release (discharge) DC power by storing gas. Each of power storage device 31, power storage device 36, and power storage device 41 constitutes a charging/discharging element. The water electrolysis cell 51 constitutes a charging element. Also, the fuel cell 61 constitutes a discharge element. Note that the hydrogen storage device 53 constitutes a charge/discharge element.
　直流バス制御システム１が有する準安定化装置の数については特に限定されない。直流バス制御システム１は、充放電要素、充電要素又は放電要素と、対応する電力変換器と、を有する少なくとも１つの準安定化装置を備えていればよい。また、直流バス制御システム１が複数の準安定化装置を備える場合、充放電要素を有する準安定化装置の数と、充電要素を有する準安定化装置の数と、放電要素を有する準安定化装置の数とは、使用状態に応じて適宜組み合わせて選択してもよい。 The number of metastabilizers that the DC bus control system 1 has is not particularly limited. The DC bus control system 1 may comprise at least one metastabilizer with charging/discharging, charging or discharging elements and a corresponding power converter. Further, when the DC bus control system 1 includes a plurality of metastabilizing devices, the number of metastabilizing devices having charge/discharge elements, the number of metastabilizing devices having charging elements, and the number of metastabilizing devices having discharging elements The number of devices may be appropriately combined and selected according to the state of use.
　各安定化装置（主安定化装置３０、補助装置３５、準安定化装置４０、準安定化装置５０及び準安定化装置６０のそれぞれ）は、直流バス７０との間で直流電力を授受する電力バッファとなる。また、主安定化装置３０、補助装置３５及び準安定化装置４０のそれぞれは充放電機能を有する電力バッファである。準安定化装置５０は充電機能を有する電力バッファである。準安定化装置６０は放電機能を有する電力バッファである。 Each stabilizing device (primary stabilizing device 30, auxiliary device 35, metastabilizing device 40, metastabilizing device 50 and metastabilizing device 60, respectively) receives and receives DC power from DC bus 70. buffer. Also, each of the main stabilizer 30, the auxiliary device 35 and the meta-stabilizer 40 is a power buffer with charging and discharging functions. Metastabilizer 50 is a power buffer with a charging function. Metastabilizer 60 is a power buffer with a discharge function.
　なお、バス電圧目標値の設定機能を有する主安定化装置３０は１台であることが望ましい。準安定化装置は、電源システムの並列数や負荷９０の要求電力に応じて必要台数だけ設けてもよい。 It is desirable that only one main stabilizer 30 has the function of setting the bus voltage target value. A required number of meta-stabilizers may be provided according to the parallel number of the power supply system and the required power of the load 90 .
　監視・指示装置８０は、主安定化装置３０、補助装置３５、準安定化装置４０、準安定化装置５０及び準安定化装置６０のそれぞれ（以下、「主安定化装置等」という。）の状態情報を収集して状態監視や動作監視を行う。状態情報は、例えば、電圧、電流、温度等が含まれる。また、監視・指示装置８０は、主安定化装置等の監視結果に基づいて運転指令及び充放電閾値指令を生成する。なお、監視・指示装置８０と、主安定化装置等との間は、有線又は無線により送受信可能である。 The monitoring/indicating device 80 monitors each of the main stabilizing device 30, the auxiliary device 35, the metastabilizing device 40, the metastabilizing device 50, and the metastabilizing device 60 (hereinafter referred to as "main stabilizing device, etc."). It collects status information and performs status monitoring and operation monitoring. State information includes, for example, voltage, current, temperature, and the like. In addition, the monitoring/instruction device 80 generates an operation command and a charge/discharge threshold command based on the monitoring results of the main stabilizer and the like. Wired or wireless communication can be performed between the monitoring/instructing device 80 and the main stabilizing device or the like.
　次に、本実施形態に係る直流バス制御システム１の各部の構成について説明する。本実施形態に係る直流バス制御システム１は、入力電源として太陽光発電システム１０及び風力発電システム２０が接続される。 Next, the configuration of each part of the DC bus control system 1 according to this embodiment will be described. A solar power generation system 10 and a wind power generation system 20 are connected to a DC bus control system 1 according to this embodiment as input power sources.
　太陽光発電システム１０及び風力発電システム２０は、再生可能エネルギーを用いた発電電力をそれぞれ電力変換器１２及び電力変換器２２により直流電力に変換して直流バス７０に供給する点で共通の機能を有する。以下では、太陽光発電システム１０を例として説明をして、風力発電システム２０については説明を省略する。 The photovoltaic power generation system 10 and the wind power generation system 20 have a common function in that power generated using renewable energy is converted into DC power by the power converters 12 and 22, respectively, and supplied to the DC bus 70. have. Below, the photovoltaic power generation system 10 will be described as an example, and the description of the wind power generation system 20 will be omitted.
　図３は、太陽光発電システム１０における電力変換器１２の一構成例を示すブロック図である。電力変換器１２は、ＤＣ／ＤＣ変換部１２Ａと、制御回路１２Ｂと、を備える。 FIG. 3 is a block diagram showing a configuration example of the power converter 12 in the photovoltaic power generation system 10. As shown in FIG. The power converter 12 includes a DC/DC converter 12A and a control circuit 12B.
　ＤＣ／ＤＣ変換部１２Ａは、半導体スイッチング素子の動作により太陽電池１１の直流出力電圧を所定の大きさの直流電圧に変換して直流バス７０に出力する。ＤＣ／ＤＣ変換部１２Ａは、例えば、昇圧チョッパによって構成される。 The DC/DC converter 12A converts the DC output voltage of the solar cell 11 into a DC voltage of a predetermined magnitude by operating the semiconductor switching element, and outputs the DC voltage to the DC bus 70 . The DC/DC converter 12A is configured by, for example, a boost chopper.
　制御回路１２Ｂは、ＤＣ／ＤＣ変換部１２Ａを制御する。制御回路１２Ｂは、電圧検出器１２ａと、電流検出器１２ｂと、ＭＰＰＴ制御部１２ｃと、電圧・電流制御部１２ｄと、駆動回路１２ｅと、電圧検出器１２ｆと、比較部１２ｇと、を備える。電圧検出器１２ａは、太陽電池１１の出力電圧を検出する。電流検出器１２ｂは、太陽電池１１の出力電流を検出する。 The control circuit 12B controls the DC/DC converter 12A. The control circuit 12B includes a voltage detector 12a, a current detector 12b, an MPPT controller 12c, a voltage/current controller 12d, a drive circuit 12e, a voltage detector 12f, and a comparator 12g. Voltage detector 12 a detects the output voltage of solar cell 11 . Current detector 12 b detects the output current of solar cell 11 .
　ＭＰＰＴ制御部１２ｃは、最大電力点追従制御（ＭＰＰＴ：Ｍａｘｉｍｕｍ　ｐｏｗｅｒ　ｐｏｉｎｔ　ｔｒａｃｋｉｎｇ）を行う。ＭＰＰＴ制御部１２ｃには、電圧検出器１２ａで検出された太陽電池１１の出力電圧と電流検出器１２ｂで検出された太陽電池１１の出力電流が入力される。ＭＰＰＴ制御部１２ｃでは、山登り法等により太陽電池１１の最大出力点を探索して電圧・電流制御部１２ｄに出力する。 The MPPT control unit 12c performs maximum power point tracking control (MPPT: Maximum power point tracking). The output voltage of the solar cell 11 detected by the voltage detector 12a and the output current of the solar cell 11 detected by the current detector 12b are input to the MPPT controller 12c. The MPPT control section 12c searches for the maximum output point of the solar cell 11 by a hill-climbing method or the like, and outputs it to the voltage/current control section 12d.
　電圧・電流制御部１２ｄは、ＭＰＰＴ制御部１２ｃからの入力に基づいてパルス幅変調（ＰＷＭ：Ｐｕｌｓｅ　Ｗｉｄｔｈ　Ｍｏｄｕｌａｔｉｏｎ）制御等により駆動パルスを生成する。電圧・電流制御部１２ｄは、生成した駆動パルスを駆動回路１２ｅに出力する。駆動回路１２ｅは、電圧・電流制御部１２ｄから出力された駆動パルスに基づいてＤＣ／ＤＣ変換部１２Ａの半導体スイッチング素子をオン及びオフさせる。 The voltage/current control unit 12d generates drive pulses by pulse width modulation (PWM) control or the like based on the input from the MPPT control unit 12c. The voltage/current control unit 12d outputs the generated drive pulse to the drive circuit 12e. The drive circuit 12e turns on and off the semiconductor switching element of the DC/DC converter 12A based on the drive pulse output from the voltage/current controller 12d.
　電圧検出器１２ｆは、直流バス７０の電圧を検出する。電圧検出器１２ｆで検出されたバス電圧検出値は後述の主安定化装置３０から送られたバス電圧目標値と共に比較部１２ｇに入力される。比較部１２ｇは、バス電圧検出値とバス電圧目標値との偏差に応じた制御信号を生成して電圧・電流制御部１２ｄに出力する。 The voltage detector 12f detects the voltage of the DC bus 70. The bus voltage detection value detected by the voltage detector 12f is input to the comparator 12g together with the bus voltage target value sent from the main stabilizing device 30, which will be described later. The comparison unit 12g generates a control signal according to the deviation between the bus voltage detection value and the bus voltage target value, and outputs the control signal to the voltage/current control unit 12d.
　電圧・電流制御部１２ｄは、比較部１２ｇから出力された制御信号に基づいて、バス電圧検出値をバス電圧目標値に一致させるような駆動パルスを演算する。電圧・電流制御部１２ｄは、例えば、バス電圧検出値がバス電圧目標値を上回る場合にはＤＣ／ＤＣ変換部１２Ａの出力電圧を低下させる（運転停止も含む）ように制御動作を行う。 The voltage/current control unit 12d calculates a drive pulse that matches the bus voltage detection value with the bus voltage target value based on the control signal output from the comparison unit 12g. For example, when the bus voltage detection value exceeds the bus voltage target value, the voltage/current control unit 12d performs a control operation to reduce the output voltage of the DC/DC conversion unit 12A (including stopping operation).
　図４は主安定化装置３０における電力変換器３２の一構成例を示すブロック図である。電力変換器３２は、ＤＣ／ＤＣ変換部３２Ａと、制御回路３２Ｂと、電流検出器３２Ｃと、を備える。 FIG. 4 is a block diagram showing a configuration example of the power converter 32 in the main stabilizer 30. As shown in FIG. The power converter 32 includes a DC/DC converter 32A, a control circuit 32B, and a current detector 32C.
　ＤＣ／ＤＣ変換部３２Ａは、直流バス７０と蓄電装置３１との間で直流電力を双方向に授受して蓄電装置３１を充放電制御する機能を有する。ＤＣ／ＤＣ変換部３２Ａは、半導体スイッチング素子を備えた絶縁型のＤＣ／ＤＣコンバータやチョッパ等により構成される。蓄電装置３１は、電圧・電流及び温度を検出するセンサ３１ｓを備える。 The DC/DC conversion unit 32A has a function of bidirectionally transferring DC power between the DC bus 70 and the power storage device 31 to control charging and discharging of the power storage device 31 . The DC/DC converter 32A is configured by an insulated DC/DC converter, a chopper, or the like, which includes a semiconductor switching element. The power storage device 31 includes a sensor 31s that detects voltage/current and temperature.
　制御回路３２Ｂは、電圧検出器３２ａと、バス電圧目標値演算部３２ｂと、減算器３２ｃと、充放電制御部３２ｄと、駆動回路３２ｅと、を備える。 The control circuit 32B includes a voltage detector 32a, a bus voltage target value calculator 32b, a subtractor 32c, a charge/discharge controller 32d, and a drive circuit 32e.
　電圧検出器３２ａは、直流バス７０の電圧を検出する。バス電圧目標値演算部３２ｂは、蓄電装置３１の蓄電量指標に応じてバス電圧目標値を演算する。なお、バス電圧目標値は、例えば、蓄電装置３１の充放電電流を測定して推定蓄電量指標を求め、当該推定蓄電指標、基準蓄電量指標及び基準バス電圧に基づいて算出する。例えば、バス電圧目標値は、直流バス７０の電圧の許容範囲内で、蓄電量指標（例えば充電率）が大きいほど高く、蓄電量指標が小さいほど低くなるように設定される。 The voltage detector 32a detects the voltage of the DC bus 70. The bus voltage target value calculation unit 32 b calculates a bus voltage target value according to the power storage amount index of the power storage device 31 . Note that the bus voltage target value is calculated, for example, by measuring the charging/discharging current of the power storage device 31 to obtain an estimated power storage amount indicator, and calculating the estimated power storage amount indicator, the reference power storage amount indicator, and the reference bus voltage. For example, the bus voltage target value is set within the permissible range of the voltage of the DC bus 70 such that the larger the stored electricity amount indicator (for example, the charging rate), the higher the bus voltage target value, and the smaller the stored electricity amount indicator, the lower the bus voltage target value.
　蓄電装置３１の蓄電量指標としては、例えば、センサ３１ｓにより検出される蓄電装置３１の充放電電流を積分して得た充電率（ＳＯＣ：Ｓｔａｔｅ　ｏｆ　Ｃｈａｒｇｅ）を用いることができる。 For example, a charging rate (SOC: State of Charge) obtained by integrating the charge/discharge current of the power storage device 31 detected by the sensor 31s can be used as the power storage amount index of the power storage device 31 .
　減算器３２ｃは、バス電圧目標値とバス電圧検出値との偏差を演算する。そして、減算器３２ｃは、演算した偏差を充放電制御部３２ｄに出力する。 The subtractor 32c calculates the deviation between the bus voltage target value and the bus voltage detection value. Then, the subtractor 32c outputs the calculated deviation to the charge/discharge control section 32d.
　充放電制御部３２ｄは、バス電圧検出値がバス電圧目標値に一致するようにＰＷＭ制御等を行って駆動パルスを生成する。充放電制御部３２ｄには、蓄電装置３１の電圧・電流、温度及び充放電閾値が入力される。充放電制御部３２ｄは、入力された蓄電装置３１の電圧・電流、温度及び充放電閾値等の情報に基づいて、バス電圧検出値がバス電圧目標値に一致するようにＰＷＭ制御等を行って駆動パルスを生成する。 The charge/discharge control unit 32d performs PWM control or the like so that the bus voltage detection value matches the bus voltage target value to generate a drive pulse. The voltage/current, temperature, and charge/discharge threshold of the power storage device 31 are input to the charge/discharge control unit 32d. The charge/discharge control unit 32d performs PWM control or the like so that the bus voltage detection value matches the bus voltage target value based on the input information such as the voltage/current, temperature, and charge/discharge threshold value of the power storage device 31. Generate drive pulses.
　駆動回路３２ｅは、充放電制御部３２ｄが生成した駆動パルスに従ってＤＣ／ＤＣ変換部３２Ａの半導体スイッチング素子をオン及びオフさせる。ＤＣ／ＤＣ変換部３２Ａは、上記のように蓄電装置３１を充放電制御してバス電圧検出値をバス電圧目標値に一致させる。 The drive circuit 32e turns on and off the semiconductor switching element of the DC/DC converter 32A according to the drive pulse generated by the charge/discharge controller 32d. The DC/DC conversion unit 32A controls charging and discharging of the power storage device 31 as described above so that the bus voltage detection value matches the bus voltage target value.
　電流検出器３２Ｃは、蓄電装置３１に充放電される電流の電流値を検出する。電流検出器３２Ｃは、検出した電流値（電流検出値）を補助装置３５の電力変換器３７に出力する。 The current detector 32C detects the current value of the current that charges and discharges the power storage device 31 . The current detector 32</b>C outputs the detected current value (current detection value) to the power converter 37 of the auxiliary device 35 .
　なお、蓄電装置３１の充放電閾値は、制御回路３２Ｂが自ら設定してもよいし、監視・指示装置８０からの指令として受信してもよい。 Note that the charge/discharge threshold of the power storage device 31 may be set by the control circuit 32B itself, or may be received as a command from the monitoring/instruction device 80.
　図５は補助装置３５における電力変換器３７の一構成例を示すブロック図である。電力変換器３７は、ＤＣ／ＤＣ変換部３７Ａと、制御回路３７Ｂと、電流検出器３７Ｃと、を備える。 FIG. 5 is a block diagram showing a configuration example of the power converter 37 in the auxiliary device 35. As shown in FIG. The power converter 37 includes a DC/DC converter 37A, a control circuit 37B, and a current detector 37C.
　ＤＣ／ＤＣ変換部３７Ａは、直流バス７０と蓄電装置３１との間で直流電力を双方向に授受して蓄電装置３１を充放電制御する機能を有する。ＤＣ／ＤＣ変換部３７Ａは、半導体スイッチング素子を備えた絶縁型のＤＣ／ＤＣコンバータやチョッパ等により構成される。蓄電装置３６は、電圧・電流及び温度を検出するセンサ３６ｓを備える。 The DC/DC conversion unit 37A has a function of bidirectionally transferring DC power between the DC bus 70 and the power storage device 31 to control charging and discharging of the power storage device 31 . The DC/DC converter 37A is configured by an insulated DC/DC converter, a chopper, or the like, which includes a semiconductor switching element. The power storage device 36 includes a sensor 36s that detects voltage/current and temperature.
　制御回路３７Ｂは、増幅器３７ａと、減算器３７ｃと、充放電制御部３７ｄと、駆動回路３７ｅと、を備える。電流検出器３７Ｃは、蓄電装置３６に充放電される電流の電流値を測定する。電流検出器３２Ｃは、測定した電流値（電流検出値）を補助装置３５の電力変換器３７に出力する。 The control circuit 37B includes an amplifier 37a, a subtractor 37c, a charge/discharge control section 37d, and a drive circuit 37e. Current detector 37</b>C measures the current value of the current that charges and discharges power storage device 36 . The current detector 32</b>C outputs the measured current value (current detection value) to the power converter 37 of the auxiliary device 35 .
　増幅器３７ａは、電流検出器３７Ｃで検出した電流検出値を、所定の増幅率で増幅する。そして、減算器３７ｃは、主安定化装置３０の電流検出器３２Ｃから入力した電流検出値と増幅器３７ａが出力した電流検出値との偏差を演算する。そして、減算器３７ｃは、演算した偏差を充放電制御部３７ｄに出力する。 The amplifier 37a amplifies the current detection value detected by the current detector 37C with a predetermined amplification factor. The subtractor 37c then calculates the deviation between the detected current value input from the current detector 32C of the main stabilizer 30 and the detected current value output from the amplifier 37a. Then, the subtractor 37c outputs the calculated deviation to the charge/discharge control section 37d.
　充放電制御部３７ｄは、増幅器３７ａが出力した電流検出値が主安定化装置３０の電流検出器３２Ｃから入力した電流検出値に一致するようにＰＷＭ制御等を行って駆動パルスを生成する。 The charge/discharge control unit 37d performs PWM control or the like so that the current detection value output from the amplifier 37a matches the current detection value input from the current detector 32C of the main stabilizer 30 to generate a drive pulse.
　駆動回路３７ｅは、充放電制御部３７ｄが生成した駆動パルスに従ってＤＣ／ＤＣ変換部３７Ａの半導体スイッチング素子をオン及びオフさせる。ＤＣ／ＤＣ変換部３７Ａは、上記のように蓄電装置３６を充放電制御して増幅器３７ａが出力した電流検出値を主安定化装置３０の電流検出器３２Ｃから入力した電流検出値に一致させる。 The drive circuit 37e turns on and off the semiconductor switching element of the DC/DC converter 37A according to the drive pulse generated by the charge/discharge controller 37d. The DC/DC conversion unit 37A controls charging and discharging of the power storage device 36 as described above, and matches the current detection value output from the amplifier 37a with the current detection value input from the current detector 32C of the main stabilizing device 30. FIG.
　上述のように制御回路３７Ｂが制御することによって、電力変換器３７は、主安定化装置３０において充放電する電流の電流値に応じた電流値の電流を蓄電装置３６において充放電するように充放電制御する。 Under the control of control circuit 37B as described above, power converter 37 charges and discharges power storage device 36 with a current value corresponding to the current value of the current charged and discharged in main stabilizer 30. discharge control.
　主安定化装置３０において充放電する電流の電流値を電流値Ｉｍ、電力変換器３７が蓄電装置３６に充放電する電流の電流値を電流値Ｉｓ、変数ｘに対して単調増加する関数をＦ（ｘ）とすると、例えば、制御回路３７Ｂは、下記の式を満たすように、電流値Ｉｍに応じて電流値Ｉｓとなるように充放電する。なお、電流値Ｉｍ及び電流値Ｉｓのそれぞれの符号は、例えば、充電する電流を正とする。 Current value Im is the current value of the current that charges and discharges in the main stabilizer 30, current value Is is the current value of the current that the power converter 37 charges and discharges to the storage device 36, and F is a function that monotonously increases with respect to the variable x. Assuming that (x), for example, the control circuit 37B charges and discharges to the current value Is according to the current value Im so as to satisfy the following equation. As for the sign of each of the current value Im and the current value Is, for example, the charging current is positive.
　　Ｉｓ　＝　Ｆ（Ｉｍ） Is = F (Im)
　関数Ｆ（ｘ）は、変数ｘに対して単調増加すれば、線形関数でもよいし、非線形関数でもよい。例えば、電流値Ｉｓが電流値Ｉｍと一致するようにしてもよいし、電流値Ｉｓが電流値Ｉｍに比例するようにしてもよい。また、電流値Ｉｍの増加量に対する電流値Ｉｓの増加量の比率（傾き）は、一定に限らず、例えば、電流値Ｉｍが大きいほど緩やかになるように、電流値Ｉｍに対して変化してもよい。 The function F(x) may be a linear function or a nonlinear function as long as it monotonically increases with respect to the variable x. For example, the current value Is may match the current value Im, or the current value Is may be proportional to the current value Im. In addition, the ratio (slope) of the amount of increase in the current value Is to the amount of increase in the current value Im is not limited to a constant value. good too.
　なお、補助装置３５の台数については、１台に限らない。例えば、直流バス制御システム１において、複数の補助装置３５を備えるようにしてもよい。 Note that the number of auxiliary devices 35 is not limited to one. For example, the DC bus control system 1 may be provided with a plurality of auxiliary devices 35 .
　例えば、主安定化装置３０の容量を大きくするために、複数の主安定化装置３０を備えるようにすると、主安定化装置３０は、直流バス７０のバス電圧を制御していることから、バス電圧の制御が複数の主安定化装置３０で競合して系が不安定になる可能性がある。 For example, if a plurality of main stabilizers 30 are provided in order to increase the capacity of the main stabilizers 30, the main stabilizers 30 control the bus voltage of the DC bus 70. There is a possibility that the control of the voltage will compete with the main stabilizers 30 and the system will become unstable.
　本実施形態に係る直流バス制御システム１によれば、直流バス７０のバス電圧の制御は、１台の主安定化装置３０で行い、補助装置３５の蓄電装置３６に、蓄電装置３１に充放電する電流の電流値に応じた充放電電流を供給することにより、充放電容量を増やすことができる。また、本実施形態に係る直流バス制御システム１によれば、直流バス７０のバス電圧の制御は、１台の主安定化装置３０で行うことにより、安定して直流バス７０のバス電圧を制御できる。 According to the DC bus control system 1 according to this embodiment, the bus voltage of the DC bus 70 is controlled by one main stabilizer 30, and the power storage device 36 of the auxiliary device 35 is charged/discharged. By supplying a charging/discharging current corresponding to the current value of the current to be applied, the charging/discharging capacity can be increased. Further, according to the DC bus control system 1 according to the present embodiment, the bus voltage of the DC bus 70 is stably controlled by performing the control of the bus voltage of the DC bus 70 by one main stabilizer 30. can.
　図６は、準安定化装置４０における電力変換器４２の一構成例を示すブロック図である。電力変換器４２は、ＤＣ／ＤＣ変換部４２Ａと、制御回路４２Ｂと、を備える。電力変換器４２は、直流バス７０と蓄電装置４１との間で直流電力を双方向に授受する点で、主安定化装置３０における電力変換器３２と同様の機能を有する。蓄電装置４１は、蓄電装置３１と同様に、電圧・電流及び温度を検出するセンサ４１ｓを備える。 FIG. 6 is a block diagram showing a configuration example of the power converter 42 in the metastabilization device 40. As shown in FIG. The power converter 42 includes a DC/DC converter 42A and a control circuit 42B. Power converter 42 has the same function as power converter 32 in main stabilizing device 30 in that DC power is bidirectionally exchanged between DC bus 70 and power storage device 41 . Like the power storage device 31, the power storage device 41 includes a sensor 41s that detects voltage/current and temperature.
　制御回路４２Ｂは、電圧検出器４２ａと、比較部４２ｂと、減算器４２ｃと、充放電制御部４２ｄと、駆動回路４２ｅと、を備える。 The control circuit 42B includes a voltage detector 42a, a comparator 42b, a subtractor 42c, a charge/discharge controller 42d, and a drive circuit 42e.
　電力変換器４２は、主安定化装置３０における電力変換器３２と以下の点で異なる。制御回路４２Ｂの充放電制御部４２ｄは、充放電閾値とバス電圧検出値との偏差に基づいて入出力電流目標値を演算する。充放電制御部４２ｄは、更に、ＤＣ／ＤＣ変換部４２Ａの入出力電流が入出力電流目標値に一致するように蓄電装置４１に対する充放電制御を行う。充放電閾値は蓄電装置４１の充放電に関する閾値（充電閾値及び放電閾値）であってよく、当該充放電閾値と直流バス７０の電圧との差分に応じて入出力電流目標値を定めてよい。 The power converter 42 differs from the power converter 32 in the main stabilizer 30 in the following points. The charge/discharge control unit 42d of the control circuit 42B calculates the input/output current target value based on the deviation between the charge/discharge threshold value and the bus voltage detection value. The charge/discharge control unit 42d further performs charge/discharge control for the power storage device 41 so that the input/output current of the DC/DC conversion unit 42A matches the input/output current target value. The charging/discharging threshold may be a threshold (charging threshold and discharging threshold) relating to charging/discharging of the power storage device 41 , and the input/output current target value may be determined according to the difference between the charging/discharging threshold and the voltage of the DC bus 70 .
　さらに、制御回路４２Ｂに設けられた比較部４２ｂは、蓄電装置４１の充放電閾値をバス電圧検出値と比較し、充電閾値又は放電閾値とバス電圧検出値との大小関係に応じて充電指令又は放電指令を出力して充放電制御部４２ｄの動作を制御する。なお、充放電閾値は、制御回路４２Ｂが自ら設定してもよいし、監視・指示装置８０から指令として受信してもよい。 Further, the comparison unit 42b provided in the control circuit 42B compares the charging/discharging threshold value of the power storage device 41 with the bus voltage detection value, and outputs a charging command or a It outputs a discharge command to control the operation of the charge/discharge controller 42d. Note that the charge/discharge threshold may be set by the control circuit 42B itself, or may be received as a command from the monitor/instruction device 80 .
　図７は準安定化装置５０における電力変換器５２の一構成例を示すブロック図である。電力変換器５２は、ＤＣ／ＤＣ変換部５２Ａと、制御回路５２Ｂと、を備える。 FIG. 7 is a block diagram showing a configuration example of the power converter 52 in the metastabilization device 50. As shown in FIG. The power converter 52 includes a DC/DC converter 52A and a control circuit 52B.
　ＤＣ／ＤＣ変換部５２Ａは、直流バス７０の直流電力を所定の大きさに変換して水電解セル５１に供給する機能を有する。ＤＣ／ＤＣ変換部５２Ａは、半導体スイッチング素子を備えた絶縁型のＤＣ／ＤＣコンバータやチョッパ等により構成される。 The DC/DC converter 52A has a function of converting the DC power of the DC bus 70 into a predetermined magnitude and supplying it to the water electrolysis cell 51. The DC/DC converter 52A is configured by an insulated DC/DC converter, a chopper, or the like, which includes a semiconductor switching element.
　水電解セル５１は、ＤＣ／ＤＣ変換部５２Ａから供給された直流電力を用いて水を電気分解する。そして、水電解セル５１により生成された水素ガスは、外部の貯蔵装置（図示せず）に貯蔵される。水電解セル５１は、直流電力を水素ガスに変換して貯蔵する動作、いいかえれば、一種の充電動作を行う。 The water electrolysis cell 51 electrolyzes water using the DC power supplied from the DC/DC converter 52A. The hydrogen gas generated by the water electrolysis cell 51 is stored in an external storage device (not shown). The water electrolysis cell 51 performs an operation of converting DC power into hydrogen gas and storing it, in other words, performs a kind of charging operation.
　ＤＣ／ＤＣ変換部５２Ａを制御する制御回路５２Ｂは、制御回路４２Ｂと同様の構成を有する。制御回路５２Ｂは、電圧検出器５２ａと、比較部５２ｂと、減算器５２ｃと、充電制御部５２ｄと、駆動回路５２ｅと、を備える。 A control circuit 52B that controls the DC/DC converter 52A has the same configuration as the control circuit 42B. The control circuit 52B includes a voltage detector 52a, a comparator 52b, a subtractor 52c, a charge controller 52d, and a drive circuit 52e.
　制御回路５２Ｂにおいて、電圧検出器５２ａにより直流バス７０の電圧が検出される。また、充電閾値とバス電圧検出値との偏差が減算器５２ｃにより演算される。そして、充電閾値とバス電圧検出値との偏差が充電制御部５２ｄに入力される。また、バス電圧検出値は充電閾値と共に比較部５２ｂに入力される。比較部５２ｂは、バス電圧検出値が充電閾値を上回ると充電指令を充電制御部５２ｄに出力する。充電閾値は、水電解セル５１による電気分解の開始電圧に相当する。すなわち、充電閾値は、水電解セル５１の充電に関する閾値である。 In the control circuit 52B, the voltage of the DC bus 70 is detected by the voltage detector 52a. Also, the deviation between the charge threshold and the bus voltage detection value is calculated by the subtractor 52c. Then, the deviation between the charge threshold value and the bus voltage detection value is input to the charge controller 52d. Also, the bus voltage detection value is input to the comparison unit 52b together with the charge threshold. The comparison unit 52b outputs a charge command to the charge control unit 52d when the bus voltage detection value exceeds the charge threshold. The charge threshold corresponds to the starting voltage of electrolysis by the water electrolysis cell 51 . That is, the charging threshold is a threshold for charging the water electrolysis cell 51 .
　充電制御部５２ｄは、減算器５２ｃから入力された充電閾値とバス電圧検出値との偏差に基づいて入出力電流目標値を演算する。そして、充電制御部５２ｄは、ＤＣ／ＤＣ変換部５２Ａの入出力電流が入出力電流目標値に一致するように充電指令としての駆動パルスを生成し、駆動回路５２ｅに出力する。駆動回路５２ｅでは、充電制御部５２ｄが生成した駆動パルスに従ってＤＣ／ＤＣ変換部５２Ａの半導体スイッチング素子をオン及びオフさせる。ＤＣ／ＤＣ変換部５２Ａは、水電解セル５１に直流電力を供給して水を電気分解する。 The charge control unit 52d calculates the input/output current target value based on the deviation between the charge threshold input from the subtractor 52c and the bus voltage detection value. Then, the charge control unit 52d generates a drive pulse as a charge command so that the input/output current of the DC/DC conversion unit 52A matches the input/output current target value, and outputs the drive pulse to the drive circuit 52e. The drive circuit 52e turns on and off the semiconductor switching element of the DC/DC converter 52A according to the drive pulse generated by the charge controller 52d. The DC/DC converter 52A supplies DC power to the water electrolysis cell 51 to electrolyze water.
　ＤＣ／ＤＣ変換部５２Ａは、上記の動作により水電解セル５１に供給される直流電力を制御しつつ、入出力電流を入出力電流目標値に一致させるように動作する。 The DC/DC converter 52A operates to match the input/output current with the input/output current target value while controlling the DC power supplied to the water electrolysis cell 51 by the above operation.
　準安定化装置６０については、燃料電池６１による発電動作を放電動作と考え、準安定化装置５０の水電解セル５１、充電閾値及び充電制御部５２ｄをそれぞれ燃料電池６１、放電閾値及び放電制御部に置き換えて構成すればよい。放電閾値は、燃料電池６１による発電の開始電圧に相当する。 As for the metastabilization device 60, the power generation operation by the fuel cell 61 is considered as the discharge operation, and the water electrolysis cell 51 and the charge threshold and charge control unit 52d of the metastabilization device 50 are the fuel cell 61 and the discharge threshold and discharge control unit, respectively. should be replaced with . The discharge threshold corresponds to the starting voltage for power generation by the fuel cell 61 .
　準安定化装置６０は、バス電圧検出値が放電閾値を下回ったときに放電指令に相当する駆動パルスを放電制御部に出力してＤＣ／ＤＣ変換部を動作させる。準安定化装置６０は、当該ＤＣ／ＤＣ変換部を動作させることにより、燃料電池６１による発電電力を、ＤＣ／ＤＣ変換部を介して直流バス７０に供給する。 The quasi-stabilization device 60 outputs a drive pulse corresponding to a discharge command to the discharge control unit to operate the DC/DC conversion unit when the bus voltage detection value falls below the discharge threshold. By operating the DC/DC converter, the meta-stabilizer 60 supplies power generated by the fuel cell 61 to the DC bus 70 via the DC/DC converter.
　ＤＣ／ＤＣ変換部は、上記の動作により燃料電池６１の発電電力を制御しつつ、入出力電流を入出力電流目標値に一致させるように動作する。 The DC/DC converter operates to match the input/output current with the input/output current target value while controlling the power generated by the fuel cell 61 through the above operation.
　なお、水電解セル５１及び燃料電池６１のそれぞれにも、電圧・電流及び温度等を検出するセンサが設けられ、これらの検出値が充電制御部５２ｄや放電制御部に入力されているが、当該センサの図示は省略している。 Each of the water electrolysis cell 51 and the fuel cell 61 is also provided with a sensor for detecting voltage, current, temperature, etc., and these detected values are input to the charge control section 52d and the discharge control section. Illustration of the sensor is omitted.
　また、充電閾値及び放電閾値は、各制御回路が自ら設定してもよいし、監視・指示装置８０から指令として受信してもよい。 Also, the charge threshold and the discharge threshold may be set by each control circuit themselves, or may be received from the monitor/instruction device 80 as a command.
　図３から図７に示した電力変換器１２、電力変換器３２、電力変換器３７、電力変換器４２及び電力変換器５２、特に制御回路１２Ｂ、制御回路３２Ｂ、制御回路３７Ｂ、制御回路４２Ｂ及び制御回路５２Ｂの構成や動作は、あくまで例示的なものであって何ら本発明の技術的範囲を限定するものではなく、これらと異なる構成を採用してもよいことは言うまでもない。 Power converter 12, power converter 32, power converter 37, power converter 42 and power converter 52 shown in FIGS. The configuration and operation of the control circuit 52B are merely examples and do not limit the technical scope of the present invention, and it goes without saying that configurations different from these may be adopted.
　次に、図８は、直流バス７０の電圧に応じた準安定化装置４０の蓄電装置４１の充放電電力、準安定化装置５０の水電解セル５１の入力電力、準安定化装置６０の燃料電池６１の出力電力を、それぞれ模式的に示した概念図である。図８における三角形シンボルの横方向の幅は各電力の大きさを示しており、幅が広いほど電力値が大きくなる。 Next, FIG. 8 shows the charge/discharge power of the electricity storage device 41 of the metastabilization device 40 according to the voltage of the DC bus 70, the input power of the water electrolysis cell 51 of the metastabilization device 50, and the fuel of the metastabilization device 60. 4A and 4B are conceptual diagrams schematically showing the output power of the battery 61. FIG. The horizontal width of the triangular symbol in FIG. 8 indicates the magnitude of each power, and the wider the width, the larger the power value.
　図８では、入力電源が再生可能エネルギー電源システムである場合を例示しており、再生可能エネルギー電源システムは、例えば、図１の太陽光発電システム１０及び風力発電システム２０である。太陽光発電システム１０及び風力発電システム２０のそれぞれの発電電力が供給される直流バス７０の電圧と蓄電装置４１、水電解セル５１、燃料電池６１の充放電閾値等に応じて、各部の充放電動作が制御される。 FIG. 8 illustrates a case where the input power source is a renewable energy power system, and the renewable energy power system is, for example, the solar power generation system 10 and the wind power generation system 20 in FIG. Charge/discharge of each part according to the voltage of the DC bus 70 to which the power generated by the solar power generation system 10 and the wind power generation system 20 is supplied and the charge/discharge threshold of the power storage device 41, the water electrolysis cell 51, and the fuel cell 61. movement is controlled.
　例えば、図８の蓄電装置４１に関する（ａ）に示すように、バス電圧が蓄電装置４１の充電閾値より高ければ高いほど蓄電装置４１に供給される充電電力は大きくなる。また、バス電圧が蓄電装置４１の放電閾値より低ければ低いほど蓄電装置４１から放出される放電電力は大きくなる。同様にして、バス電圧が水電解セル５１の充電閾値より高ければ高いほど水電解セル５１に供給される充電電力は大きくなる。また、バス電圧が燃料電池６１の放電閾値より低ければ低いほど燃料電池６１から発生する放電電力は大きくなる。 For example, as shown in (a) regarding the power storage device 41 in FIG. 8, the charging power supplied to the power storage device 41 increases as the bus voltage is higher than the charging threshold of the power storage device 41 . Also, the lower the bus voltage is below the discharge threshold of power storage device 41, the greater the discharge power discharged from power storage device 41 becomes. Similarly, the higher the bus voltage is higher than the charging threshold of the water electrolysis cell 51, the greater the charge power supplied to the water electrolysis cell 51 becomes. Also, the lower the bus voltage is below the discharge threshold of the fuel cell 61, the greater the discharge power generated from the fuel cell 61 becomes.
　図８の蓄電装置４１に関する（ｂ）は、基準バス電圧に応じて充電閾値及び放電閾値を（ａ）より低く設定した場合、（ｃ）は充電閾値及び放電閾値を（ａ）より高く設定した場合を示す。同様の閾値の設定変更操作は水電解セル５１の充電閾値及び燃料電池６１の放電閾値に対しても可能である。 In (b) of the power storage device 41 in FIG. 8, the charge threshold and discharge threshold are set lower than (a) according to the reference bus voltage, and in (c) the charge threshold and discharge threshold are set higher than (a). indicate the case. A similar threshold setting change operation is also possible for the charging threshold of the water electrolysis cell 51 and the discharging threshold of the fuel cell 61 .
　蓄電装置４１、水電解セル５１及び燃料電池６１の充電閾値及び放電閾値を変化させて充放電動作を制御することにより、直流バス７０と準安定化装置４０、準安定化装置５０及び準安定化装置６０との間で授受される直流電力を個別に調整することができる。いいかえると、それぞれの電力バッファとしての動作をきめ細かく制御することが可能である。 By changing the charge threshold and discharge threshold of the power storage device 41, the water electrolysis cell 51, and the fuel cell 61 to control the charge and discharge operation, the DC bus 70, the metastabilization device 40, the metastabilization device 50, and the metastabilization device 50 are controlled. The DC power sent to and received from device 60 can be individually adjusted. In other words, it is possible to finely control the operation of each power buffer.
　充電閾値及び放電閾値の変更は、監視・指示装置８０からの指令に基づいて行ってもよいし、電力変換器４２、電力変換器５２及び電力変換器６２のそれぞれが自ら行ってもよい。 The charge threshold and discharge threshold may be changed based on a command from the monitoring/instruction device 80, or may be changed by the power converter 42, the power converter 52, and the power converter 62 by themselves.
　なお、蓄電装置３１が第１の充放電要素の一例、電力変換器３２が第１の電力変換器の一例、蓄電装置４１が第２の充放電要素の一例、電力変換器４２、電力変換器５２及び電力変換器６２のいずれかが第２の電力変換器の一例、蓄電装置３６が第３の充放電要素の一例、電力変換器３７が第３の電力変換器の一例、である。 Note that the power storage device 31 is an example of a first charging/discharging element, the power converter 32 is an example of a first power converter, the power storage device 41 is an example of a second charging/discharging element, a power converter 42, and a power converter. Either 52 or power converter 62 is an example of a second power converter, power storage device 36 is an example of a third charge/discharge element, and power converter 37 is an example of a third power converter.
　＜直流バス制御システム１の安定性＞
　本実施形態に係る直流バス制御システム１の安定性について説明する。なお、以下の説明において、主安定化装置３０及び補助装置３５をまとめて主安定化装置（ＭＶＣ：Ｍａｉｎ　Ｖｏｌｔａｇｅ　Ｃｏｎｔｒｏｌｌｅｒ）、準安定化装置４０、準安定化装置５０及び準安定化装置６０をまとめて準安定化装置（ＳＶＣ：Ｓｕｂ　Ｖｏｌｔａｇｅ　Ｃｏｎｔｒｏｌｌｅｒ）と呼ぶ。 <Stability of DC bus control system 1>
The stability of the DC bus control system 1 according to this embodiment will be described. In the following description, the main stabilizing device 30 and the auxiliary device 35 are collectively referred to as the main stabilizing device (MVC: Main Voltage Controller), the metastabilizing device 40, the metastabilizing device 50, and the metastabilizing device 60. is called a meta-stabilizer (SVC: Sub Voltage Controller).
　［主安定化装置］
　主安定化装置はバス電圧ＶＢを制御する。バス電圧ＶＢは、主安定化装置により、式１に従って決定する。すなわち、主安定化装置のＤＣ／ＤＣ変換部は定電圧出力の双方向コンバータである。 [Main stabilizer]
The main stabilizer controls the bus voltage VB . The bus voltage VB is determined according to Equation 1 by the main stabilizer. That is, the DC/DC converter of the main stabilizer is a bi-directional converter with a constant voltage output.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　なお、ＣＭＶＣは主安定化装置における蓄電デバイスの容量、ＩＭＶＣは主安定化装置における蓄電デバイスに流れる電流（充電する電流を正とする。）、ＶＢ０はバイアス電圧、ＱＭＶＣは主安定化装置における蓄電デバイスに充電された電荷量、である。 Here, C MVC is the capacity of the storage device in the main stabilizer, I MVC is the current flowing through the storage device in the main stabilizer (charge current is assumed to be positive), V B0 is the bias voltage, and Q MVC is the main stabilizer. is the amount of electric charge charged in the electricity storage device in the conversion device.
　主安定化装置は、最大供給／吸収電力を超える場合には、上記ＶＢを制御目標電圧としながらも、蓄電デバイスの最大供給／吸収電力で定電流制御に移行する。定電流制御の場合には、準安定化装置を含め、すべてのデバイスが定電流となるため、準安定化装置が余剰・不足を吸収・放電するようにバス電圧が自動的に決定される。したがって、バス電圧は、ＶＢに制御され、主安定化装置からは定電流で最大供給電力が供給される。すなわち、直流バス制御システム１は、主安定化装置がハンドリング可能な電力を超える電力を制御できる。しかしながら、主安定化装置がハンドリング可能な電力を超える電力が供給されている場合は、主安定化装置における蓄電デバイスに充電された電荷量の絶対値が大きくなり、通常の準安定化装置の安定制御範囲を外れてしまう。 When the maximum supply/absorption power is exceeded, the main stabilizer shifts to constant current control with the maximum supply/absorption power of the storage device while setting VB as the control target voltage. In the case of constant current control, since all devices including the metastabilizer have constant current, the bus voltage is automatically determined so that the metastabilizer absorbs and discharges the surplus/shortage. Therefore, the bus voltage is regulated to VB and the maximum supply power is supplied from the main stabilizer at constant current. That is, the DC bus control system 1 can control power that exceeds the power that the main stabilizer can handle. However, if the power supplied exceeds the power that the main stabilizer can handle, the absolute value of the amount of charge charged in the storage device in the main stabilizer increases, and the stability of the normal metastabilizer increases. out of control range.
　なお、上述のように、主安定化装置のハンドリング能力を超えたパワーの入出力があった場合にも直流バス制御システム１は停止しない。しかしながら、直流バス制御システム１の応答は、通常の線形応答にはならない。また、直流バス制御システム１の回復時間は、この間に積分された電荷を放出・吸収する時間になる。回復時間は、おおむね、オーバーロード時間と同じ程度の時間がかかる。 It should be noted that, as described above, the DC bus control system 1 does not stop even when power input/output exceeds the handling capability of the main stabilizer. However, the response of the DC bus control system 1 is not the usual linear response. Also, the recovery time of the DC bus control system 1 is the time for discharging and absorbing the charges integrated during this period. The recovery time is roughly as long as the overload time.
　直流バス制御システム１において、オーバーロードの条件がなくなった場合にできるだけ早く線形な制御にもどすことは、式１におけるＱＭＶＣをＱＭＶＣの絶対値が線形制御の範囲又は線形制御の範囲より少し大きい値に制限することで実現できる。ただし、直流バス制御システム１が線形な制御に戻ったとしても、物理的なＱＭＶＣにオフセットが生じる。すなわち、蓄電デバイスの充電率にオフセットが生じる。 In the DC bus control system 1, returning to linear control as quickly as possible when the overload condition is removed requires Q MVC in Eq. This can be achieved by restricting the values. However, even if the DC bus control system 1 returns to linear control, there will be an offset in the physical Q MVC . That is, an offset occurs in the charging rate of the power storage device.
　［準安定化装置］
　準安定化装置はバス電圧で決定される電流（又は電力で定義してもよい）を発生・吸収する。バス電圧ＶＢの値に関わらず、電力の出し入れをするため、定電流源・定電流負荷のインタフェースを持つ。発生・吸収電流ＩＳＶＣは、一般に式２で表される。 [Metastabilization device]
A metastabilizer generates and absorbs a current (or as may be defined in terms of power) determined by the bus voltage. It has a constant current source/constant current load interface in order to supply and receive power regardless of the value of the bus voltage VB . The generated and absorbed current I SVC is generally represented by Equation 2.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　準安定化装置において、発生・吸収が可能な双方向デバイス、発生のみが可能なデバイス及び吸収のみが可能なデバイスのそれぞれは、関数ＩＳＶＣ（）の関数系の違いとして表せる。ここでは、符号は、直流バスから電力を吸収する方向を正とする。なお、符号については、逆の定義にしてもよい。 In the metastabilization device, each of the two-way device capable of generation/absorption, the device capable of only generation, and the device capable of only absorption can be expressed as different functional systems of the function I SVC ( ). Here, the sign is positive in the direction of power absorption from the DC bus. Note that the sign may be defined in the opposite way.
　例えば、吸収のみが可能なデバイスの場合は下記の式で表される。 For example, in the case of a device that can only absorb, it is represented by the following formula.
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　また、例えば、発生のみが可能なデバイスの場合は下記の式で表される。 Also, for example, in the case of a device that can only generate, it is represented by the following formula.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　なお、上記の例では、ａはコンダクタンスの次元を有する。電力で制御する場合も、係数のディメンジョンが変更することにより同様の定式化ができる。 Note that in the above example, a has the dimension of conductance. In the case of power control as well, similar formulation can be achieved by changing the dimensions of the coefficients.
　［外部デバイス］
　電力消費機器や発電デバイス等の外部デバイスは、電流モード（例えば、定電流源）として直流バスに接続する。外部デバイスの総消費電流Ｉｅｘｔは、式３のように示される。なお、符号は、電力消費を正とする。 [External device]
External devices, such as power consumers and generator devices, connect to the DC bus as current mode (eg, constant current source). A total current consumption I ext of the external device is expressed as in Equation 3. Note that the sign is positive for power consumption.
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　［制御の特性につて］
　式１における電流ＩＭＶＣは、変換効率やバイアス電流を考慮すれば、蓄電デバイスの実際の充放電電流としても、直流バス側の電流としてもよい。ここでは、電流ＩＭＶＣを蓄電デバイスの電流とする。直流バス上での電力収支を式４に示す。なお、Ｂはオフセット電流である。 [Regarding control characteristics]
The current I MVC in Equation 1 may be the actual charge/discharge current of the power storage device or the current on the DC bus side, if the conversion efficiency and the bias current are taken into consideration. Here, the current IMVC is the current of the storage device. Equation 4 shows the power balance on the DC bus. Note that B is an offset current.
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　式１及び式２より、下記の関係が得られる。 The following relationship is obtained from Equations 1 and 2.
Figure JPOXMLDOC01-appb-M000007
Figure JPOXMLDOC01-appb-M000007
　したがって、上記の関係を利用すると、下記の関係が導かれる。 Therefore, using the above relationship leads to the following relationship.
Figure JPOXMLDOC01-appb-M000008
Figure JPOXMLDOC01-appb-M000008
　ここで、外部デバイスの消費電力が一定であれば下記の関係を示す。 Here, if the power consumption of the external device is constant, the following relationship is shown.
Figure JPOXMLDOC01-appb-M000009
Figure JPOXMLDOC01-appb-M000009
　したがって、式５に示すように、直流バス制御システム１は、一次遅れ系の応答を示す。 Therefore, as shown in Equation 5, the DC bus control system 1 exhibits a first-order lag system response.
Figure JPOXMLDOC01-appb-M000010
Figure JPOXMLDOC01-appb-M000010
Figure JPOXMLDOC01-appb-M000011
Figure JPOXMLDOC01-appb-M000011
　外部消費電力が一定であれば、バス電圧は所定の時定数で一定値に収束する。この時、ＩＭＶＣは零になる。したがって、本実施形態に係る直流バス制御システム１は、発振することなく安定して動作できる。 If the external power consumption is constant, the bus voltage converges to a constant value with a predetermined time constant. At this time, I MVC becomes zero. Therefore, the DC bus control system 1 according to this embodiment can operate stably without oscillation.
　なお、オーバーロード対策を行わない場合でも、充電効率の制御を行わないと、長時間運転はできない。主安定化装置に使用する蓄電デバイスの効率が有限であり、効率の推定が正確にできない。効率はデバイスの温度や色々なパラメーターによって変わる。また、制御において、継続的に蓄電デバイスを充放電する。制御において計算上のＱＭＶＣは一定になっても、実デバイスのＱＭＶＣとの乖離が起き、比較的短時間で、蓄電デバイスは枯渇するか、飽和する可能性がある。 It should be noted that even if no countermeasures against overload are taken, long-term operation is not possible unless the charging efficiency is controlled. The efficiency of the storage device used in the primary stabilizer is finite and cannot be accurately estimated. Efficiency varies with device temperature and other parameters. Also, in the control, the electric storage device is continuously charged and discharged. Even if the calculated Q MVC is constant in control, a deviation from the Q MVC of the actual device may occur, and the storage device may become depleted or saturated in a relatively short period of time.
　蓄電デバイスの充電効率は端子電圧から推定できる。ただし、端子電圧は、充放電電流に依存するため、充放電電流を零にして測定する必要がある。充放電電流を零にすることは、外部デバイスが安定している場合に自動的に達成されることを使い、次式で充電効率の制御を組み込むことができる。 　The charging efficiency of the storage device can be estimated from the terminal voltage. However, since the terminal voltage depends on the charging/discharging current, it is necessary to set the charging/discharging current to zero and measure it. Using the fact that zero charge/discharge current is automatically achieved when the external device is stable, we can incorporate control of charge efficiency with the following equation.
Figure JPOXMLDOC01-appb-M000012
 　なお、ＶＳｏＣは蓄電デバイスの端子電圧、ＶＴは蓄電デバイス端子電圧の制御目標値、を示す。第２項の積分は、ＩＭＶＣの絶対値が閾値Ｉｔｈより小さい場合のみに実施することを意味する。閾値Ｉｔｈは経験値として設定するスレッショルド電流値である。上記の式は、実際には離散化して計算、制御する。
Figure JPOXMLDOC01-appb-M000012
 Note that V SoC indicates the terminal voltage of the storage device, and V T indicates the control target value of the storage device terminal voltage. The integration of the second term is meant to be performed only if the absolute value of I MVC is less than the threshold I th . The threshold Ith is a threshold current value set as an empirical value. The above formula is actually calculated and controlled by discretization.
　また、上記のように複数台の準安定化装置の動作を平準化させる運用方法以外に、個々の準安定化装置の反応応答性や充電容量等を考慮して、例えば、ある準安定化装置については満充電に近い状態で動作させ、他の準安定化装置についてはほぼ完全に放電させた状態で動作させるというように、充電電力及び放電電力に優先順位をつけて運用する方法も考えられる。 In addition to the operation method of equalizing the operations of a plurality of metastabilizers as described above, in consideration of the reaction responsiveness and charge capacity of each metastabilizer, for example, a certain metastabilizer It is also conceivable to prioritize the charging power and discharging power, such as operating the other metastabilizers in a nearly fully charged state and operating the other metastabilization devices in an almost completely discharged state. .
　以上、本発明を実施例に基づいて説明したが、本発明は上記実施例に限定されるものではなく、特許請求の範囲に記載の範囲内で様々な変形が可能である。 Although the present invention has been described above based on the examples, the present invention is not limited to the above examples, and various modifications are possible within the scope of the claims.
　本願は、日本特許庁に２０２１年９月２９日に出願された基礎特許出願２０２１－１６０１３２号の優先権を主張するものであり、その全内容を参照によりここに援用する。 This application claims priority from Basic Patent Application No. 2021-160132 filed on September 29, 2021 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.
１　直流バス制御システム
１０　太陽光発電システム
２０　風力発電システム
３０　主安定化装置
３６　蓄電装置
４０、５０、５０Ａ、６０　準安定化装置
３１、３６、４１、４６　蓄電装置
５１　水電解セル
６１　燃料電池
３２、３７、４２、５２、６２　電力変換器
７０　直流バス
８０　監視・指示装置
９０　負荷 1 DC bus control system 10 solar power generation system 20 wind power generation system 30 main stabilizer 36 power storage devices 40, 50, 50A, 60 meta- stabilization devices 31, 36, 41, 46 power storage device 51 water electrolysis cell 61 fuel cell 32 , 37, 42, 52, 62 power converter 70 DC bus 80 monitor/indicator 90 load

Claims (5)

  1. 　入力電源と負荷との間を接続する直流バスの電力変動を制御する直流バス制御システムであって、
    　第１の充放電要素と第１の電力変換器とを有する主安定化装置と、
    　第２の充放電要素、充電要素又は放電要素と第２の電力変換器とを有する少なくとも１つの準安定化装置と、
    　第３の充放電要素と第３の電力変換器とを有する補助装置と、
    を含み、
    　前記第１の電力変換器は、前記第１の充放電要素の蓄電量指標に応じたバス電圧目標値を求め、前記バス電圧目標値に前記直流バスの電圧が一致するように、前記第１の充放電要素と前記直流バスとの間で直流電力を双方向に授受するよう構成され、
    　前記第２の電力変換器は、前記第２の充放電要素、充電要素又は放電要素の充電又は放電に関する閾値と前記直流バスの前記電圧との差分に応じて電流目標値を求め、前記電流目標値に等しい電流が前記第２の充放電要素、充電要素又は放電要素に流れるように、前記第２の充放電要素、充電要素又は放電要素と前記直流バスとの間で直流電力を授受するよう構成され、
    　前記第１の電力変換器は、前記第１の充放電要素に流れる電流の電流値を検出し、
    　前記第３の電力変換器は、前記電流値に応じた電流値を有する充放電電流により、前記第３の充放電要素と前記直流バスとの間で直流電力を授受するよう構成される、
    　ことを特徴とする直流バス制御システム。     A DC bus control system for controlling power fluctuations in a DC bus connecting between an input power supply and a load,
    a main stabilizer having a first charging/discharging element and a first power converter;
    at least one metastabilization device having a second charging/discharging element, charging element or discharging element and a second power converter;
    an auxiliary device having a third charging/discharging element and a third power converter;
    including
    The first power converter obtains a bus voltage target value in accordance with the storage amount index of the first charging/discharging element, and adjusts the first bus voltage so that the voltage of the DC bus matches the bus voltage target value. DC power is bidirectionally exchanged between the charge/discharge element of and the DC bus,
    The second power converter obtains a current target value in accordance with a difference between a threshold for charging or discharging of the second charging/discharging element, charging element, or discharging element and the voltage of the DC bus, and calculates the current target value. to transfer DC power between the second charging/discharging element, charging element or discharging element and the DC bus such that a current equal to the value flows through the second charging/discharging element, charging element or discharging element configured,
    The first power converter detects a current value of a current flowing through the first charging/discharging element,
    The third power converter is configured to transfer DC power between the third charging/discharging element and the DC bus by charging/discharging current having a current value corresponding to the current value.
    A DC bus control system characterized by:
  2. 　前記第１の電力変換器は、前記第１の充放電要素に流れる電流の電流値を検出する電流検出器を備える、
    請求項１に記載の直流バス制御システム。     The first power converter includes a current detector that detects the current value of the current flowing through the first charging/discharging element.
    The DC bus control system of claim 1.
  3. 　前記第３の電力変換器は、前記電流検出器が測定した前記電流値に基づいて、前記充放電電流を制御する、
    請求項２に記載の直流バス制御システム。     The third power converter controls the charge/discharge current based on the current value measured by the current detector.
    3. The DC bus control system of claim 2.
  4. 　前記入力電源として再生可能エネルギー電源システムを更に含む、
    請求項１から請求項３のいずれか一項に記載の直流バス制御システム。     further comprising a renewable energy power system as the input power source;
    A DC bus control system according to any one of claims 1 to 3.
  5. 　前記負荷を更に含む、
    請求項１から請求項４のいずれか一項に記載の直流バス制御システム。     further comprising the load;
    A DC bus control system according to any one of claims 1 to 4.
PCT/JP2022/036033 2021-09-29 2022-09-27 Dc bus control system WO2023054406A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013145618A1 (en) * 2012-03-26 2013-10-03 パナソニック株式会社 Charging/discharging control device and charging/discharging control method
WO2019103059A1 (en) * 2017-11-21 2019-05-31 国立研究開発法人理化学研究所 Direct-current bus control system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013145618A1 (en) * 2012-03-26 2013-10-03 パナソニック株式会社 Charging/discharging control device and charging/discharging control method
WO2019103059A1 (en) * 2017-11-21 2019-05-31 国立研究開発法人理化学研究所 Direct-current bus control system

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