WO2020161766A1 - Direct-current power supply system - Google Patents

Direct-current power supply system Download PDF

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Publication number
WO2020161766A1
WO2020161766A1 PCT/JP2019/003849 JP2019003849W WO2020161766A1 WO 2020161766 A1 WO2020161766 A1 WO 2020161766A1 JP 2019003849 W JP2019003849 W JP 2019003849W WO 2020161766 A1 WO2020161766 A1 WO 2020161766A1
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Prior art keywords
power
bidirectional
storage batteries
converters
bus
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PCT/JP2019/003849
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French (fr)
Japanese (ja)
Inventor
琢真 光永
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Tdk株式会社
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Priority to PCT/JP2019/003849 priority Critical patent/WO2020161766A1/en
Publication of WO2020161766A1 publication Critical patent/WO2020161766A1/en

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00Circuit arrangements for dc mains or dc distribution networks
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10Parallel operation of dc sources
    • H02J1/12Parallel operation of dc generators with converters, e.g. with mercury-arc rectifier
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00Circuit arrangements for dc mains or dc distribution networks
    • H02J1/14Balancing the load in a network
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/35Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells

Definitions

  • the present invention relates to a DC power supply system, and particularly to a DC power supply system configured by combining a natural energy power generation device such as a solar power generation device and a plurality of storage batteries.
  • the demand forecast data of load devices and the power generation output forecast data of a natural energy power generation device are calculated using weather forecast data, and the maximum of the storage battery is calculated based on the demand forecast data and the power generation output data.
  • the power output from the renewable energy power generation device is suppressed, and when it is predicted that the storage battery will be discharged in excess of the maximum discharge power of the storage battery. Describes a method of suppressing the power consumption of the adjustment load.
  • Patent Document 2 a plurality of storage batteries are charged after the power generated by the solar power generation device is temporarily stored in an electric double layer capacitor, and at least one of the plurality of storage batteries to be charged reaches a full charge.
  • a method is described in which all storage batteries are charged by removing them from the charging target and sequentially selecting and charging other storage batteries that are not the charging target.
  • an object of the present invention is to provide a DC power supply system capable of suppressing variations in charging rates of a plurality of storage batteries connected to a DC bus and preventing a decrease in charge/discharge capacity of the entire storage battery.
  • a DC power supply system includes a DC bus that is a bus for DC power supply, a natural energy power generation device that supplies generated power to the DC bus, and a load power supply from the DC bus.
  • a load device a plurality of bidirectional DC/DC converters connected to the DC bus, and a plurality of storage batteries respectively connected to the DC bus via any one of the plurality of bidirectional DC/DC converters
  • a power management device that manages the operations of the plurality of bidirectional DC/DC converters based on the generated power, the load power, and the charging rates of the plurality of storage batteries. It is characterized in that the output voltage of the bidirectional DC/DC converter corresponding to each storage battery is controlled according to the charging rate.
  • the present invention it is possible to prevent variations in the charging rates of a plurality of storage batteries that are supplied with generated power from a natural energy power generation device via a DC bus, and prevent a decrease in the charge/discharge capacity of the entire storage battery.
  • the plurality of bidirectional DC/DC converters include first and second DC/DC converters, and the plurality of storage batteries are respectively connected to the first and second DC/DC converters.
  • the power management apparatus includes first and second storage batteries, and when the charging rates of all the storage batteries including the first and second storage batteries are equal to or less than a first threshold value, the power management device includes the first and second storage batteries. Output voltages of all the bidirectional DC/DC converters including the bidirectional DC/DC converter are set to a first voltage, and a charging rate of at least the first storage battery is larger than the first threshold value, and at least the first threshold value is set.
  • the charging rate of the second storage battery is less than or equal to the first threshold value
  • the first threshold value is 80% or more and 95% or less of the maximum capacity of the first and second storage batteries. In this way, when at least one of the plurality of storage batteries approaches the full charge in advance, the storage battery is not fully charged, and the other storage batteries that are not close to the full charge are given priority. Therefore, the generated power can be efficiently charged. Therefore, the charging rates of a plurality of storage batteries can be equalized, and a decrease in the charging ability of the entire storage batteries can be prevented.
  • the power management device may be configured such that when the charging rates of all storage batteries including the first and second storage batteries are equal to or higher than a second threshold value that is smaller than the first threshold value, the first and second bidirectional operations are performed. Output voltages of all bidirectional DC/DC converters including DC/DC converters are set to the first voltage, and a charging rate of at least the first storage battery is smaller than the second threshold value, and at least the second threshold value. It is preferable that the output voltage of the first bidirectional DC/DC converter is set to a third voltage lower than the first voltage when the charging rate of the storage battery is equal to or higher than the second threshold value.
  • the second threshold value is preferably 5% or more and 20% or less of the maximum capacities of the first and second storage batteries.
  • the first voltage is a reference voltage of the DC bus.
  • the reference voltage of the DC bus is 350V
  • the first voltage is set to 350V
  • the second voltage is set to 370V
  • the third voltage is set to 330V, so that the charging rates of the plurality of storage batteries are equalized. Therefore, it is possible to prevent a decrease in the charging capacity of the entire storage battery.
  • FIG. 1 is a block diagram schematically showing a configuration of a DC power supply system according to an embodiment of the present invention.
  • 2A and 2B are diagrams for explaining the operation of the DC power supply system, in which FIG. 2A shows the charging operation of the storage battery and FIG. 2B shows the discharging operation of the storage battery.
  • FIG. 3 is a schematic diagram for explaining control of the bidirectional DC/DC converter by the power management device, showing a case where the charging rates of the storage batteries 50A to 50C are not more than the second threshold and not less than the first threshold.
  • FIG. 4 is a schematic diagram illustrating a control method of the bidirectional DC/DC converter by the power management device, and illustrates a case where the charging rate of the storage battery 50A is larger than the first threshold value.
  • FIG. 5 is a schematic diagram illustrating a control method of the bidirectional DC/DC converter by the power management device, and illustrates a case where the charging rates of the storage batteries 50A and 50B are larger than the first threshold value.
  • FIG. 6 is a schematic diagram for explaining the control method of the bidirectional DC/DC converter by the power management device, and shows the case where the charging rates of the storage batteries 50A, 50B, 50C are larger than the first threshold value.
  • FIG. 7 is a schematic diagram illustrating a control method of the bidirectional DC/DC converter by the power management device, and illustrates a case where the charging rate of the storage battery 50A is smaller than the second threshold value.
  • FIG. 1 is a block diagram schematically showing the configuration of a DC power supply system according to an embodiment of the present invention.
  • the DC power supply system 1 includes a DC bus 10 serving as a bus for DC power supply, DC/DC converters 21 to 23 connected to the DC bus 10, and a DC bus via the DC/DC converter 21.
  • a natural energy power generation device 30 connected to the DC power supply device 10, a load device 40 connected to the DC bus 10 via the DC/DC converter 22, and a storage battery 50 connected to the DC bus 10 via the DC/DC converter 23.
  • the power management apparatus 60 that manages the entire system including the operations of the DC/DC converters 21 to 23 and the power management apparatus 60 that can communicate with the power management apparatus 60 via a communication network 70 such as the Internet so that the storage battery 50 is discharged. Further, the administrator terminal 71 is further provided.
  • the voltage of the DC bus 10 is, for example, a high voltage DC transmission line of 350 ⁇ 100V. Therefore, when connecting a device operating at a voltage lower than that to the DC bus 10, it is necessary to connect via a DC/DC converter.
  • the DC/DC converter 21 is a one-way DC/DC converter (step-up converter) that boosts the generated power of, for example, 240 V from the natural energy power generation device 30 to 350 V and supplies the boosted power to the DC bus 10
  • the DC/DC converter 22 is Is a one-way DC/DC converter (step-down converter) that steps down the electric power of 350 V on the DC bus 10 to 24 V and supplies it to the load device 40.
  • the DC/DC converter 23 is a bidirectional DC/DC converter that steps down or boosts the power on the DC bus 10 and supplies it to the storage battery 50, and boosts or steps down the power from the storage battery 50 and supplies it to the DC bus 10. is there.
  • the DC/DC converters 21 to 23 have an ON/OFF command receiving function and a power amount adjustment command receiving function, and are configured to be communicable with the power management device 60.
  • the natural energy power generation device 30 is, for example, a solar power generation device 30A or a wind power generation device 30B.
  • the photovoltaic power generation device 30A includes a photovoltaic power generation panel and a power conditioner, and is connected to the DC bus 10 via the DC/DC converter 21A.
  • the wind turbine generator 30B includes a wind turbine generator body and a power conditioner, and is connected to the DC bus 10 via a DC/DC converter 21B.
  • the DC/DC converters 21A and 21B may be built in each power conditioner.
  • the power conditioner has an MPPT (Maximum Power Point Tracking) function, an ON/OFF command receiving function, a power amount adjustment command receiving function, a power generation information transmitting function, and the like, and is configured to communicate with the power management device 60. ..
  • the type and number of the natural energy power generation devices 30 connected to the DC bus 10 are not particularly limited, but it is preferable to include the solar power generation device 30A.
  • the electric power generated by the solar power generation device 30A and the wind power generation device 30B is supplied to the load device 40 and the storage battery 50 via the DC bus 10.
  • the load device 40 is, for example, a PC, an air conditioner, a TV, an LED lighting, or the like. These load devices 40A to 40D are connected to the DC bus 10 via the DC/DC converters 22A to 22D, respectively, and receive power from the DC bus 10.
  • the storage battery 50 includes a plurality of storage batteries 50A to 50C, and each storage battery 50A to 50C includes a storage battery main body (battery cell) and a BMU (Battery Management Unit) for monitoring and controlling the charging state.
  • the storage batteries 50A to 50C are connected to the DC bus 10 via the bidirectional DC/DC converters 23A to 23C, respectively, and the power generated by the natural energy power generation device 30 is less than the power consumed by the load device 40 (load power).
  • load power When the load power is larger than the generated power, the excess power of the generated power is charged, and when the load power is larger than the generated power, the excess power is discharged to supplement the shortage of the load power.
  • the storage batteries 50A to 50C have substantially the same maximum capacity and charge/discharge performance.
  • the BMU of the storage battery 50 has an ON/OFF command receiving function, a DC bus voltage adjustment command receiving function, a charging/discharging current amount adjustment command receiving function, a storage battery information transmitting function, etc., and is configured to communicate with the power management device 60. Has been done.
  • the SOC State Of Charge: remaining capacity (Ah)/full charge capacity (Ah) ⁇ 100) indicating the charging rates of the storage batteries 50A to 50C is appropriately notified to the power management apparatus 60.
  • the DC power supply system 1 may further include a diesel generator 35.
  • the amount of generated power can be forcibly increased by operating the diesel generator 35 when the amount of power generated by the natural energy power generation device 30 is small or when the remaining amount of the storage battery 50 is small. Therefore, it is possible to suppress load power and avoid power failure, and it is possible to stably supply power to the load device 40.
  • the diesel generator 35 can be used as a power source when starting up the entire system including the DC bus 10. Since the diesel generator 35 generally has an AC output, the diesel generator 35 is connected to the DC bus 10 via the AC/DC converter 24.
  • the power management device 60 is a computer system equipped with an EMS (Energy Management System).
  • the power management device 60 can remotely control the input/output operations of the DC/DC converters 21 to 23, and can control the power generation amount of the natural energy power generation device 30 and the power demand of the load device 40.
  • the power management device 60 commands the natural energy power generation device 30, the load device 40, and the storage battery 50, and collects information from these devices.
  • the collection of commands and information to these devices is performed using a communication method such as RS-232C, RS-485, CAN (Controller Area Network), Ethernet, Wi-Fi.
  • FIG. 2A and 2B are diagrams for explaining the operation of the DC power supply system 1, where FIG. 2A shows the charging operation of the storage battery 50 and FIG. 2B shows the discharging operation of the storage battery 50. There is.
  • the storage battery 50 charges the surplus of the generated power amount.
  • the generated power from the natural energy power generation device 30 is supplied to the storage battery 50 via the DC/DC converter 21, the DC bus 10, and the DC/DC converter 22.
  • the storage battery 50 is discharged to supply the necessary power to the load device 40. Electric power from the storage battery 50 is supplied to the load device 40 via the DC/DC converter 23, the DC bus 10 and the DC/DC converter 22.
  • 3 to 7 are schematic diagrams illustrating a method of controlling the bidirectional DC/DC converters 23A to 23C by the power management device 60.
  • the SOC of each of the storage batteries 50A to 50C is less than or equal to the upper threshold (first threshold) SOC TH set near the maximum capacity (100%), and set near 0%.
  • the power management apparatus 60 sets the output voltage (grid target voltage) of the DC/DC converters 23A to 23C to the DC bus 10 to 350V which is the reference voltage of the DC bus 10. It is maintained at (first voltage).
  • the first threshold SOC TH is preferably set to 80% or more and 95% or less of the maximum capacity of the storage batteries 50A to 50C
  • the second threshold SOC TL is 5% or more of the maximum capacity of the storage batteries 50A to 50C. It is preferable to set it to be not more than %.
  • the generated power is supplied from the natural energy power generation device 30 to the DC bus 10 and the voltage of the DC bus 10 is When trying to exceed 350 V, current flows from the DC bus 10 toward the storage batteries 50A to 50C, and the storage batteries 50A to 50C are charged.
  • a current flows from the storage batteries 50A to 50C toward the DC bus 10 and the storage batteries 50A to 50C are discharged. ..
  • FIG. 3 shows a state in which the charging rates of the storage batteries 50A to 50C have some variations.
  • the power management device 60 changes the output voltage of the bidirectional DC/DC converter 23A connected to the storage battery 50A to another value. It is set higher than the output voltage of the two bidirectional DC/DC converters 23B and 23C.
  • the output voltage of the bidirectional DC/DC converter 23A is set to 370V (second voltage), and the output voltages of the other bidirectional DC/DC converters 23B and 23C are maintained at 350V (first voltage). ..
  • the storage battery 50A is less likely to be charged than the other storage batteries 50B and 50C, and it is possible to prevent the storage battery 50A from being fully charged, and all the storage batteries 50A to 50C can be charged and discharged. It is possible to maintain a good state. Therefore, it is possible to prevent waste of the generated power of the natural energy power generation device due to loss reduction. Further, it is possible to prevent the system from going down by suppressing the voltage fluctuation of the DC bus 10.
  • the power management device 60 sets the output voltage of the bidirectional DC/DC converters 23A and 23B connected to the storage batteries 50A and 50B to the other one. It is set higher than the output voltage of the DC/DC converter 23C.
  • the output voltage of the bidirectional DC/DC converters 23A and 23B is set to 370V, and the output voltage of the bidirectional DC/DC converter 23C is maintained at 350V.
  • the storage batteries 50A and 50B are less likely to be charged than the other storage batteries 50C, and it is possible to prevent the storage batteries 50A and 50B from being fully charged, and all the storage batteries 50A to 50C are charged. The dischargeable state can be maintained.
  • the output voltages of all the bidirectional DC/DC converters 23A to 23C are lower than the reference voltage of the DC bus.
  • a high voltage for example, 370V
  • the output voltages of all the bidirectional DC/DC converters 23A to 23C may be returned to the reference voltage (350V) of the DC bus 10.
  • the power management apparatus 60 stop the power generation operation of the natural energy power generation apparatus 30.
  • the power management device 60 changes the output voltage of the bidirectional DC/DC converter 23A connected to the storage battery 50A to another value. It is set lower than the output voltage of the two bidirectional DC/DC converters 23B and 23C.
  • the output voltage of the bidirectional DC/DC converter 23A is set to 330V (third voltage), and the output voltages of the other two bidirectional DC/DC converters 23B and 23C are maintained at 350V (first voltage). To be done.
  • the DC power supply system 1 includes the plurality of storage batteries 50A to 50C connected to the DC bus 10 via the bidirectional DC/DC converters 23A to 23C and the bidirectional DC/DC converter 23A.
  • Power management device 60 for controlling the operations of the storage batteries 50A to 23C. Since the output voltage is changed, it is possible not only to suppress the variation in the charging rate between the storage batteries 50A to 50C and prevent the charging/discharging ability of the entire storage battery 50 from decreasing, but also to stabilize the DC bus 10.
  • the number of storage batteries may be any number as long as it is two or more (a plurality).
  • the output voltage of the DC/DC converter is changed in two steps (350 V ⁇ 370 V) based on one SOC threshold value.
  • the DC/DC converter output voltage is changed by using two or more SOC threshold values. It is also possible to change the output voltage in multiple stages (for example, 350V ⁇ 360V ⁇ 370V).

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

[Problem] To suppress variation in the charging rates of a plurality of storage batteries connected to a direct-current bus so as to prevent a reduction in the charge/discharge capability of the storage batteries as an entirety. [Solution] A direct-current power supply system 1 comprises: a direct-current bus 10 serving as the bus of a direct-current power supply; a natural energy power generation device 30 for supplying generated power to the direct-current bus 10; a load device 40 for receiving the supply of power from the direct-current bus 10; a plurality of bidirectional DC/DC converters 23A-23C connected to the direct-current bus 10; a plurality of storage batteries 50A-50C individually connected to the direct-current bus 10 via one of the plurality of bidirectional DC/DC converters 23A-23C; and a power management device 60 for managing the operation of the plurality of bidirectional DC/DC converters 23A-23C on the basis of the generated power, the load power, and the charging rates of the plurality of storage batteries. The power management device 60 controls the output voltages of the bidirectional DC/DC converters 23A-23C corresponding to each storage battery in accordance with the charging rate of each storage battery.

Description

直流給電システムDC power supply system
 本発明は、直流給電システムに関し、特に、太陽光発電装置等の自然エネルギー発電装置と複数の蓄電池とを組み合わせて構成された直流給電システムに関する。 The present invention relates to a DC power supply system, and particularly to a DC power supply system configured by combining a natural energy power generation device such as a solar power generation device and a plurality of storage batteries.
 温暖化や酸性雨をはじめとする地球規模の環境問題の顕在化、化石資源の枯渇、エネルギーセキュリティー確保等への対応策として、風力や太陽光といった自然エネルギーを利用した発電設備の導入が進んでいる。 As a measure to address global environmental problems such as global warming and acid rain, depletion of fossil resources, and security of energy security, the introduction of power generation equipment using natural energy such as wind and solar is advancing. There is.
 特に熱帯地域における隔離地や過疎地の系統未整備地域では、現状では主にディーゼルエンジン発電機等により電力が供給されていることが多いが、日照条件がよく太陽光発電に適していることもあり、再生可能エネルギーを有効活用して経済性向上を図るとともに、低炭素社会の実現にも貢献可能な電力供給システムに対するニーズは高い。また、電力系統インフラが既に整備されている地域においても、自然災害等で電力系統が停止した場合に、需要家設備に設置されている太陽光発電システムを系統と切り離して自律運転させ、電力系統停止時にも負荷に対して安定かつ継続的に電力を供給する直流給電システムへの期待が高まっている。 Especially in isolated areas and undeveloped areas in depopulated areas in the tropical region, power is often supplied mainly by diesel engine generators at present, but the sunlight conditions are good and it is suitable for solar power generation. Therefore, there is a great need for a power supply system that can contribute to the realization of a low-carbon society while improving the economic efficiency by effectively utilizing renewable energy. Even in areas where the power system infrastructure has already been developed, if the power system is shut down due to a natural disaster, etc., the solar power generation system installed in the customer's equipment will be separated from the system to operate autonomously. Expectations are increasing for a DC power supply system that supplies stable and continuous power to a load even when it is stopped.
 直流給電システムに関し、例えば特許文献1には、気象予測データを用いて負荷機器の需要予測データ及び自然エネルギー発電装置の発電出力予測データを計算し、需要予測データ及び発電出力データにより、蓄電池の最大充電電力を超えて蓄電池に充電されることが予測される場合には自然エネルギー発電装置からの発電出力を抑制し、蓄電池の最大放電電力を超えて蓄電池から放電されることが予測される場合には調整用負荷の消費電力を抑制する方法が記載されている。 Regarding a DC power supply system, for example, in Patent Document 1, the demand forecast data of load devices and the power generation output forecast data of a natural energy power generation device are calculated using weather forecast data, and the maximum of the storage battery is calculated based on the demand forecast data and the power generation output data. When it is predicted that the storage battery will be charged in excess of the charging power, the power output from the renewable energy power generation device is suppressed, and when it is predicted that the storage battery will be discharged in excess of the maximum discharge power of the storage battery. Describes a method of suppressing the power consumption of the adjustment load.
 また特許文献2には、太陽光発電装置の発電電力を電気二重層キャパシタにいったん蓄えてから複数の蓄電池の充電を行うと共に、充電対象の複数個の蓄電池のうちの少なくとも一つが満充電に達した場合に充電対象から外し、充電対象となっていない他の蓄電池を順次選択して充電することにより、すべての蓄電池に対して充電を実施する方法が記載されている。 Further, in Patent Document 2, a plurality of storage batteries are charged after the power generated by the solar power generation device is temporarily stored in an electric double layer capacitor, and at least one of the plurality of storage batteries to be charged reaches a full charge. In this case, a method is described in which all storage batteries are charged by removing them from the charging target and sequentially selecting and charging other storage batteries that are not the charging target.
国際公開第2013/128731号パンフレットInternational publication 2013/128731 pamphlet 特開2001-69688号公報JP 2001-69688 A
 上記のように、独立に充放電可能な複数の蓄電池が直流バスに接続されている場合、それらの蓄電池が均等に充放電させるように制御することは難しく、複数の蓄電池間に充電率のばらつきが生じる。いずれか一つの蓄電池が先行して満充電になると、蓄電池全体の容量が低下し、自然エネルギー発電装置がせっかく発電した電力を蓄電池に充電することができないという場合がある。予備の蓄電池を使用する場合には発電電力の無駄を防止することができるが、予備の蓄電池を設けることによるシステムコストの増加の問題がある。 As described above, when a plurality of storage batteries that can be charged and discharged independently are connected to the DC bus, it is difficult to control the storage batteries so that they are charged and discharged evenly, and there are variations in the charging rate among the storage batteries. Occurs. When any one of the storage batteries precedes to be fully charged, the capacity of the entire storage battery decreases, and it may not be possible to charge the storage battery with the electric power generated by the natural energy power generation device. When a spare storage battery is used, it is possible to prevent waste of generated power, but there is a problem in that the system cost increases due to the provision of the spare storage battery.
 特許文献1に記載された従来のシステムのように、蓄電池が満充電になることが予測される場合に発電電力を抑制する場合には、ロスカットによる発電電力の無駄が大きく、蓄電池が充電可能な最大電力量が低下する。 When the generated power is suppressed when the storage battery is predicted to be fully charged as in the conventional system described in Patent Document 1, the waste power of the generated power due to the loss cut is large and the storage battery can be charged. Maximum power consumption is reduced.
 また特許文献2に記載された従来のシステムのように、充電対象の充電池が満充電となった場合に他の蓄電池を選択して順次充電することにより複数の蓄電池の充電を実行する場合には、複数の蓄電池のトータルの容量を自然エネルギー発電装置の最大発電量よりも十分に大きくしなければならず、より多くの蓄電池を用意する必要があるため、システムコストの増加につながる。 Further, when the rechargeable battery to be charged is fully charged, as in the conventional system described in Patent Document 2, when another rechargeable battery is selected and sequentially charged, a plurality of rechargeable batteries are charged. Requires the total capacity of a plurality of storage batteries to be sufficiently larger than the maximum power generation amount of the natural energy power generation device, and it is necessary to prepare more storage batteries, which leads to an increase in system cost.
 したがって、本発明の目的は、直流バスに接続された複数の蓄電池の充電率のばらつきを抑えて蓄電池全体の充放電能力の低下を防止することが可能な直流給電システムを提供することにある。 Therefore, an object of the present invention is to provide a DC power supply system capable of suppressing variations in charging rates of a plurality of storage batteries connected to a DC bus and preventing a decrease in charge/discharge capacity of the entire storage battery.
 上記課題を解決するため、本発明による直流給電システムは、直流給電の母線となる直流バスと、前記直流バスに発電電力を供給する自然エネルギー発電装置と、前記直流バスから負荷電力の供給を受ける負荷機器と、前記直流バスに接続された複数の双方向DC/DCコンバータと、前記複数の双方向DC/DCコンバータのいずれか一つを介して前記直流バスにそれぞれ接続された複数の蓄電池と、前記発電電力、前記負荷電力及び前記複数の蓄電池の充電率に基づいて、前記複数の双方向DC/DCコンバータの動作を管理する電力管理装置とを備え、前記電力管理装置は、各蓄電池の充電率に応じて各蓄電池に対応する前記双方向DC/DCコンバータの出力電圧を制御することを特徴とする。 In order to solve the above problems, a DC power supply system according to the present invention includes a DC bus that is a bus for DC power supply, a natural energy power generation device that supplies generated power to the DC bus, and a load power supply from the DC bus. A load device, a plurality of bidirectional DC/DC converters connected to the DC bus, and a plurality of storage batteries respectively connected to the DC bus via any one of the plurality of bidirectional DC/DC converters A power management device that manages the operations of the plurality of bidirectional DC/DC converters based on the generated power, the load power, and the charging rates of the plurality of storage batteries. It is characterized in that the output voltage of the bidirectional DC/DC converter corresponding to each storage battery is controlled according to the charging rate.
 本発明によれば、自然エネルギー発電装置から直流バスを介して発電電力の供給を受ける複数の蓄電池の充電率のばらつきを抑えて蓄電池全体の充放電能力の低下を防止することができる。 According to the present invention, it is possible to prevent variations in the charging rates of a plurality of storage batteries that are supplied with generated power from a natural energy power generation device via a DC bus, and prevent a decrease in the charge/discharge capacity of the entire storage battery.
 本発明において、前記複数の双方向DC/DCコンバータは、第1及び第2のDC/DCコンバータを含み、前記複数の蓄電池は、前記第1及び第2のDC/DCコンバータにそれぞれ接続された第1及び第2の蓄電池を含み、前記電力管理装置は、前記第1及び第2の蓄電池を含むすべての蓄電池の充電率が第1の閾値以下である場合に、前記第1及び第2の双方向DC/DCコンバータを含むすべての双方向DC/DCコンバータの出力電圧を第1の電圧に設定し、少なくとも前記第1の蓄電池の充電率が前記第1の閾値よりも大きく、少なくとも前記第2の蓄電池の充電率が前記第1の閾値以下である場合に、前記第1の双方向DC/DCコンバータの出力電圧を前記第1の電圧よりも高い第2の電圧に設定することが好ましい。この場合、前記第1の閾値は、前記第1及び第2の蓄電池の最大容量の80%以上95%以下であることが好ましい。このように、複数の蓄電池のうちの少なくとも一つが先行して満充電に近づいた場合に、当該蓄電池を完全に満充電にすることなく、満充電に近づいていない他の蓄電池の充電を優先することができ、発電電力を効率よく充電することができる。したがって、複数の蓄電池の充電率の均等化を図ることができ、蓄電池全体の充電能力の低下を防止することができる。 In the present invention, the plurality of bidirectional DC/DC converters include first and second DC/DC converters, and the plurality of storage batteries are respectively connected to the first and second DC/DC converters. The power management apparatus includes first and second storage batteries, and when the charging rates of all the storage batteries including the first and second storage batteries are equal to or less than a first threshold value, the power management device includes the first and second storage batteries. Output voltages of all the bidirectional DC/DC converters including the bidirectional DC/DC converter are set to a first voltage, and a charging rate of at least the first storage battery is larger than the first threshold value, and at least the first threshold value is set. When the charging rate of the second storage battery is less than or equal to the first threshold value, it is preferable to set the output voltage of the first bidirectional DC/DC converter to a second voltage higher than the first voltage. .. In this case, it is preferable that the first threshold value is 80% or more and 95% or less of the maximum capacity of the first and second storage batteries. In this way, when at least one of the plurality of storage batteries approaches the full charge in advance, the storage battery is not fully charged, and the other storage batteries that are not close to the full charge are given priority. Therefore, the generated power can be efficiently charged. Therefore, the charging rates of a plurality of storage batteries can be equalized, and a decrease in the charging ability of the entire storage batteries can be prevented.
 前記電力管理装置は、前記第1及び第2の蓄電池を含むすべての蓄電池の充電率が前記第1の閾値よりも小さい第2の閾値以上である場合に、前記第1及び第2の双方向DC/DCコンバータを含むすべての双方向DC/DCコンバータの出力電圧を前記第1の電圧に設定し、少なくとも前記第1の蓄電池の充電率が前記第2の閾値よりも小さく、少なくとも前記第2の蓄電池の充電率が前記第2の閾値以上である場合に、前記第1の双方向DC/DCコンバータの出力電圧を前記第1の電圧よりも低い第3の電圧に設定することが好ましい。この場合、前記第2の閾値は、前記第1及び第2の蓄電池の最大容量の5%以上20%以下であることが好ましい。このように、複数の蓄電池のうちの少なくとも一つが先行して空(0%)に近づいた場合に、当該蓄電池を完全に空にすることなく、空に近づいていない他の蓄電池の放電を優先することができ、負荷電力を効率よく供給することができる。したがって、複数の蓄電池の充電率の均等化を図ることができ、蓄電池全体の充電能力の低下を防止することができる。 The power management device may be configured such that when the charging rates of all storage batteries including the first and second storage batteries are equal to or higher than a second threshold value that is smaller than the first threshold value, the first and second bidirectional operations are performed. Output voltages of all bidirectional DC/DC converters including DC/DC converters are set to the first voltage, and a charging rate of at least the first storage battery is smaller than the second threshold value, and at least the second threshold value. It is preferable that the output voltage of the first bidirectional DC/DC converter is set to a third voltage lower than the first voltage when the charging rate of the storage battery is equal to or higher than the second threshold value. In this case, the second threshold value is preferably 5% or more and 20% or less of the maximum capacities of the first and second storage batteries. In this way, when at least one of the plurality of storage batteries approaches the empty (0%) in advance, the other storage batteries that are not close to the empty are given priority without completely emptying the storage battery. Therefore, the load power can be efficiently supplied. Therefore, the charging rates of a plurality of storage batteries can be equalized, and a decrease in the charging ability of the entire storage batteries can be prevented.
 本発明において、前記第1の電圧は、前記直流バスの基準電圧であることが好ましい。例えば直流バスの基準電圧が350Vである場合に、第1の電圧を350Vとし、第2の電圧を370Vとし、第3の電圧を330Vとすることにより、複数の蓄電池の充電率の均等化を図ることができ、蓄電池全体の充電能力の低下を防止することができる。 In the present invention, it is preferable that the first voltage is a reference voltage of the DC bus. For example, when the reference voltage of the DC bus is 350V, the first voltage is set to 350V, the second voltage is set to 370V, and the third voltage is set to 330V, so that the charging rates of the plurality of storage batteries are equalized. Therefore, it is possible to prevent a decrease in the charging capacity of the entire storage battery.
 本発明によれば、直流バスに接続された複数の蓄電池の充電率のばらつきを抑えて蓄電池全体の充放電能力の低下を防止することが可能な直流給電システムを提供することにある。 According to the present invention, it is an object of the present invention to provide a DC power supply system capable of preventing variations in charging rates of a plurality of storage batteries connected to a DC bus and preventing a decrease in charge/discharge capacity of the entire storage battery.
図1は、本発明の実施の形態による直流給電システムの構成を概略的に示すブロック図である。FIG. 1 is a block diagram schematically showing a configuration of a DC power supply system according to an embodiment of the present invention. 図2(a)及び(b)は、直流給電システムの動作を説明するための図であって、(a)は蓄電池の充電動作、(b)は蓄電池の放電動作をそれぞれ示している。2A and 2B are diagrams for explaining the operation of the DC power supply system, in which FIG. 2A shows the charging operation of the storage battery and FIG. 2B shows the discharging operation of the storage battery. 図3は、電力管理装置による双方向DC/DCコンバータの制御を説明する模式図であって、蓄電池50A~50Cの充電率が第2の閾値以下且つ第1の閾値以上である場合を示している。FIG. 3 is a schematic diagram for explaining control of the bidirectional DC/DC converter by the power management device, showing a case where the charging rates of the storage batteries 50A to 50C are not more than the second threshold and not less than the first threshold. There is. 図4は、電力管理装置による双方向DC/DCコンバータの制御方法を説明する模式図であって、蓄電池50Aの充電率が第1の閾値よりも大きい場合を示している。FIG. 4 is a schematic diagram illustrating a control method of the bidirectional DC/DC converter by the power management device, and illustrates a case where the charging rate of the storage battery 50A is larger than the first threshold value. 図5は、電力管理装置による双方向DC/DCコンバータの制御方法を説明する模式図であって、蓄電池50A,50Bの充電率が第1の閾値よりも大きい場合を示している。FIG. 5 is a schematic diagram illustrating a control method of the bidirectional DC/DC converter by the power management device, and illustrates a case where the charging rates of the storage batteries 50A and 50B are larger than the first threshold value. 図6は、電力管理装置による双方向DC/DCコンバータの制御方法を説明する模式図であって、蓄電池50A,50B,50Cの充電率が第1の閾値よりも大きい場合を示している。FIG. 6 is a schematic diagram for explaining the control method of the bidirectional DC/DC converter by the power management device, and shows the case where the charging rates of the storage batteries 50A, 50B, 50C are larger than the first threshold value. 図7は、電力管理装置による双方向DC/DCコンバータの制御方法を説明する模式図であって、蓄電池50Aの充電率が第2の閾値よりも小さい場合を示している。FIG. 7 is a schematic diagram illustrating a control method of the bidirectional DC/DC converter by the power management device, and illustrates a case where the charging rate of the storage battery 50A is smaller than the second threshold value.
 以下、添付図面を参照しながら、本発明の好ましい実施の形態について詳細に説明する。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
 図1は、本発明の実施の形態による直流給電システムの構成を概略的に示すブロック図である。 FIG. 1 is a block diagram schematically showing the configuration of a DC power supply system according to an embodiment of the present invention.
 図1に示すように、直流給電システム1は、直流給電の母線となる直流バス10と、直流バス10に接続されたDC/DCコンバータ21~23と、DC/DCコンバータ21を介して直流バス10に接続された自然エネルギー発電装置30と、DC/DCコンバータ22を介して直流バス10に接続された負荷機器40と、DC/DCコンバータ23を介して直流バス10に接続された蓄電池50と、自然エネルギー発電装置30による発電電力量と負荷機器40による負荷電力量とを比較し、発電電力量が負荷電力量を上回る場合に蓄電池50を充電し、負荷電力量が発電電力量を上回る場合に蓄電池50が放電するように、DC/DCコンバータ21~23の動作を含むシステム全体を管理する電力管理装置60と、インターネット等の通信ネットワーク70を介して電力管理装置60と通信可能に構成された管理者端末71をさらに備えている。 As shown in FIG. 1, the DC power supply system 1 includes a DC bus 10 serving as a bus for DC power supply, DC/DC converters 21 to 23 connected to the DC bus 10, and a DC bus via the DC/DC converter 21. A natural energy power generation device 30 connected to the DC power supply device 10, a load device 40 connected to the DC bus 10 via the DC/DC converter 22, and a storage battery 50 connected to the DC bus 10 via the DC/DC converter 23. , Comparing the amount of power generated by the natural energy power generator 30 with the amount of load power generated by the load device 40, charging the storage battery 50 when the amount of power generation exceeds the amount of load power, and the amount of load power exceeds the amount of power generation The power management apparatus 60 that manages the entire system including the operations of the DC/DC converters 21 to 23 and the power management apparatus 60 that can communicate with the power management apparatus 60 via a communication network 70 such as the Internet so that the storage battery 50 is discharged. Further, the administrator terminal 71 is further provided.
 直流バス10の電圧は、例えば350±100Vの高圧直流伝送路である。そのため、それよりも低い電圧で動作する機器を直流バス10に接続する場合には、DC/DCコンバータを介して接続する必要がある。DC/DCコンバータ21は、自然エネルギー発電装置30からの例えば240Vの発電電力を350Vまで昇圧して直流バス10に供給する一方向DC/DCコンバータ(昇圧コンバータ)であり、DC/DCコンバータ22は、直流バス10上の350Vの電力を24Vまで降圧して負荷機器40に供給する一方向DC/DCコンバータ(降圧コンバータ)である。DC/DCコンバータ23は、直流バス10上の電力を降圧または昇圧して蓄電池50に供給すると共に、蓄電池50からの電力を昇圧または降圧して直流バス10に供給する双方向DC/DCコンバータである。DC/DCコンバータ21~23は、ON/OFF指令受信機能及び電力量調整指令受信機能を有しており、電力管理装置60と通信可能に構成されている。 The voltage of the DC bus 10 is, for example, a high voltage DC transmission line of 350±100V. Therefore, when connecting a device operating at a voltage lower than that to the DC bus 10, it is necessary to connect via a DC/DC converter. The DC/DC converter 21 is a one-way DC/DC converter (step-up converter) that boosts the generated power of, for example, 240 V from the natural energy power generation device 30 to 350 V and supplies the boosted power to the DC bus 10, and the DC/DC converter 22 is Is a one-way DC/DC converter (step-down converter) that steps down the electric power of 350 V on the DC bus 10 to 24 V and supplies it to the load device 40. The DC/DC converter 23 is a bidirectional DC/DC converter that steps down or boosts the power on the DC bus 10 and supplies it to the storage battery 50, and boosts or steps down the power from the storage battery 50 and supplies it to the DC bus 10. is there. The DC/DC converters 21 to 23 have an ON/OFF command receiving function and a power amount adjustment command receiving function, and are configured to be communicable with the power management device 60.
 自然エネルギー発電装置30は、例えば太陽光発電装置30Aや風力発電装置30Bなどである。本実施形態において、太陽光発電装置30Aは太陽光発電パネル及びパワーコンディショナーを含み、DC/DCコンバータ21Aを介して直流バス10に接続されている。風力発電装置30Bは風力発電機本体及びパワーコンディショナーを含み、DC/DCコンバータ21Bを介して直流バス10に接続されている。DC/DCコンバータ21A,21Bは、それぞれのパワーコンディショナーに内蔵されたものであってもよい。パワーコンディショナーは、MPPT(Maximum Power Point Tracking)機能、ON/OFF指令受信機能、電力量調整指令受信機能、発電情報送信機能等を有しており、電力管理装置60と通信可能に構成されている。直流バス10に接続される自然エネルギー発電装置30の種類や台数は特に限定されないが、太陽光発電装置30Aを含むことが好ましい。太陽光発電装置30Aや風力発電装置30Bが発電した電力は、直流バス10を介して負荷機器40や蓄電池50に供給される。 The natural energy power generation device 30 is, for example, a solar power generation device 30A or a wind power generation device 30B. In the present embodiment, the photovoltaic power generation device 30A includes a photovoltaic power generation panel and a power conditioner, and is connected to the DC bus 10 via the DC/DC converter 21A. The wind turbine generator 30B includes a wind turbine generator body and a power conditioner, and is connected to the DC bus 10 via a DC/DC converter 21B. The DC/ DC converters 21A and 21B may be built in each power conditioner. The power conditioner has an MPPT (Maximum Power Point Tracking) function, an ON/OFF command receiving function, a power amount adjustment command receiving function, a power generation information transmitting function, and the like, and is configured to communicate with the power management device 60. .. The type and number of the natural energy power generation devices 30 connected to the DC bus 10 are not particularly limited, but it is preferable to include the solar power generation device 30A. The electric power generated by the solar power generation device 30A and the wind power generation device 30B is supplied to the load device 40 and the storage battery 50 via the DC bus 10.
 負荷機器40は、例えばPC、エアコン、TV、LED照明などである。これらの負荷機器40A~40Dは、DC/DCコンバータ22A~22Dを介して直流バス10にそれぞれ接続されており、直流バス10から電力の供給を受ける。 The load device 40 is, for example, a PC, an air conditioner, a TV, an LED lighting, or the like. These load devices 40A to 40D are connected to the DC bus 10 via the DC/DC converters 22A to 22D, respectively, and receive power from the DC bus 10.
 蓄電池50は、複数の蓄電池50A~50Cを含み、各蓄電池50A~50Cは蓄電池本体(バッテリーセル)と充電状態を監視し制御するためのBMU(Battery Management Unit)を含む。蓄電池50A~50Cは、双方向DC/DCコンバータ23A~23Cを介して直流バス10にそれぞれ接続されており、自然エネルギー発電装置30の発電電力が負荷機器40によって消費される電力(負荷電力)よりも大きい場合には発電電力の余剰分を充電し、負荷電力が発電電力よりも大きい場合には放電して負荷電力の不足分を補充する。蓄電池50A~50Cは実質同一の最大容量及び充放電性能を有する。蓄電池50のBMUは、ON/OFF指令受信機能、直流バス電圧調整指令受信機能、充放電電流量調整指令受信機能、蓄電池情報送信機能等を有しており、電力管理装置60と通信可能に構成されている。各蓄電池50A~50Cの充電率を示すSOC(State Of Charge:残容量(Ah)/満充電容量(Ah)×100)は電力管理装置60に適宜通知される。 The storage battery 50 includes a plurality of storage batteries 50A to 50C, and each storage battery 50A to 50C includes a storage battery main body (battery cell) and a BMU (Battery Management Unit) for monitoring and controlling the charging state. The storage batteries 50A to 50C are connected to the DC bus 10 via the bidirectional DC/DC converters 23A to 23C, respectively, and the power generated by the natural energy power generation device 30 is less than the power consumed by the load device 40 (load power). When the load power is larger than the generated power, the excess power of the generated power is charged, and when the load power is larger than the generated power, the excess power is discharged to supplement the shortage of the load power. The storage batteries 50A to 50C have substantially the same maximum capacity and charge/discharge performance. The BMU of the storage battery 50 has an ON/OFF command receiving function, a DC bus voltage adjustment command receiving function, a charging/discharging current amount adjustment command receiving function, a storage battery information transmitting function, etc., and is configured to communicate with the power management device 60. Has been done. The SOC (State Of Charge: remaining capacity (Ah)/full charge capacity (Ah)×100) indicating the charging rates of the storage batteries 50A to 50C is appropriately notified to the power management apparatus 60.
 直流給電システム1は、ディーゼル発電機35をさらに備えていてもよい。自然エネルギー発電装置30の発電電力が小さい場合や蓄電池50の残量が少ない場合にディーゼル発電機35を動作させることにより、発電電力量を強制的に増加させることができる。したがって、負荷電力の抑制や停電を回避することができ、負荷機器40に対して電力を安定的に供給することが可能である。また、直流バス10を含むシステム全体をスタートアップする際の電力源としてディーゼル発電機35を使用することができる。一般的にディーゼル発電機35はAC出力であるため、ディーゼル発電機35はAC/DCコンバータ24を介して直流バス10に接続される。 The DC power supply system 1 may further include a diesel generator 35. The amount of generated power can be forcibly increased by operating the diesel generator 35 when the amount of power generated by the natural energy power generation device 30 is small or when the remaining amount of the storage battery 50 is small. Therefore, it is possible to suppress load power and avoid power failure, and it is possible to stably supply power to the load device 40. Further, the diesel generator 35 can be used as a power source when starting up the entire system including the DC bus 10. Since the diesel generator 35 generally has an AC output, the diesel generator 35 is connected to the DC bus 10 via the AC/DC converter 24.
 電力管理装置60はEMS(Energy Management System)を装備するコンピュータシステムである。電力管理装置60はDC/DCコンバータ21~23の入出力動作を遠隔制御することができ、自然エネルギー発電装置30の発電量や負荷機器40の電力需要を制御することができる。電力管理装置60は、直流バス10の電圧を維持するため、自然エネルギー発電装置30、負荷機器40、蓄電池50に指令すると共に、これらの機器から情報を収集する。これらの機器への指令及び情報の収集は、RS-232C、RS-485、CAN(Controller Area Network)、Ethrnet、Wi-Fiなどの通信方式を用いて行われる。 The power management device 60 is a computer system equipped with an EMS (Energy Management System). The power management device 60 can remotely control the input/output operations of the DC/DC converters 21 to 23, and can control the power generation amount of the natural energy power generation device 30 and the power demand of the load device 40. In order to maintain the voltage of the DC bus 10, the power management device 60 commands the natural energy power generation device 30, the load device 40, and the storage battery 50, and collects information from these devices. The collection of commands and information to these devices is performed using a communication method such as RS-232C, RS-485, CAN (Controller Area Network), Ethernet, Wi-Fi.
 図2(a)及び(b)は、直流給電システム1の動作を説明するための図であって、(a)は蓄電池50の充電動作、(b)は蓄電池50の放電動作をそれぞれ示している。 2A and 2B are diagrams for explaining the operation of the DC power supply system 1, where FIG. 2A shows the charging operation of the storage battery 50 and FIG. 2B shows the discharging operation of the storage battery 50. There is.
 図2(a)に示すように、自然エネルギー発電装置30による発電電力量が負荷機器40の負荷電力量よりも大きい場合、蓄電池50は発電電力量の余剰分を充電する。自然エネルギー発電装置30からの発電電力は、DC/DCコンバータ21、直流バス10及びDC/DCコンバータ22を介して蓄電池50に供給される。 As shown in FIG. 2A, when the amount of power generated by the natural energy power generation device 30 is larger than the load power amount of the load device 40, the storage battery 50 charges the surplus of the generated power amount. The generated power from the natural energy power generation device 30 is supplied to the storage battery 50 via the DC/DC converter 21, the DC bus 10, and the DC/DC converter 22.
 図2(b)に示すように、負荷機器40の負荷電力量が自然エネルギー発電装置30による発電電力量よりも大きい場合、蓄電池50を放電させて負荷機器40に必要な電力を供給する。蓄電池50からの電力は、DC/DCコンバータ23、直流バス10及びDC/DCコンバータ22を介して負荷機器40に供給される。 As shown in FIG. 2B, when the load power amount of the load device 40 is larger than the power generation amount of the natural energy power generation device 30, the storage battery 50 is discharged to supply the necessary power to the load device 40. Electric power from the storage battery 50 is supplied to the load device 40 via the DC/DC converter 23, the DC bus 10 and the DC/DC converter 22.
 図3~図7は、電力管理装置60による双方向DC/DCコンバータ23A~23Cの制御方法を説明する模式図である。 3 to 7 are schematic diagrams illustrating a method of controlling the bidirectional DC/DC converters 23A to 23C by the power management device 60.
 図3に示すように、蓄電池50A~50CのSOCがいずれも最大容量(100%)近くに設定された上側閾値(第1の閾値)SOCTH以下であり、且つ、0%近くに設定された下側閾値(第2の閾値)SOCTL以上である場合、電力管理装置60はDC/DCコンバータ23A~23Cの直流バス10に対する出力電圧(グリッド目標電圧)を直流バス10の基準電圧である350V(第1の電圧)に維持する。第1の閾値SOCTHは、蓄電池50A~50Cの最大容量の80%以上95%以下に設定されることが好ましく、第2の閾値SOCTLは、蓄電池50A~50Cの最大容量の5%以上20%以下に設定されることが好ましい。 As shown in FIG. 3, the SOC of each of the storage batteries 50A to 50C is less than or equal to the upper threshold (first threshold) SOC TH set near the maximum capacity (100%), and set near 0%. When the lower threshold (second threshold) SOC TL or more, the power management apparatus 60 sets the output voltage (grid target voltage) of the DC/DC converters 23A to 23C to the DC bus 10 to 350V which is the reference voltage of the DC bus 10. It is maintained at (first voltage). The first threshold SOC TH is preferably set to 80% or more and 95% or less of the maximum capacity of the storage batteries 50A to 50C, and the second threshold SOC TL is 5% or more of the maximum capacity of the storage batteries 50A to 50C. It is preferable to set it to be not more than %.
 上記のように双方向DC/DCコンバータ23A~23Cの出力電圧が一律に350Vに設定されている場合において、自然エネルギー発電装置30から直流バス10に発電電力が供給されて直流バス10の電圧が350Vを上回ろうとする場合には、直流バス10から蓄電池50A~50Cに向かって電流が流れて各蓄電池50A~50Cが充電される。一方、負荷機器40によって電力が消費されて直流バス10の電圧が350Vを下回ろうとする場合には、蓄電池50A~50Cから直流バス10に向かって電流が流れて各蓄電池50A~50Cが放電する。 When the output voltages of the bidirectional DC/DC converters 23A to 23C are uniformly set to 350 V as described above, the generated power is supplied from the natural energy power generation device 30 to the DC bus 10 and the voltage of the DC bus 10 is When trying to exceed 350 V, current flows from the DC bus 10 toward the storage batteries 50A to 50C, and the storage batteries 50A to 50C are charged. On the other hand, when power is consumed by the load device 40 and the voltage of the DC bus 10 is about to fall below 350V, a current flows from the storage batteries 50A to 50C toward the DC bus 10 and the storage batteries 50A to 50C are discharged. ..
 上記のように双方向DC/DCコンバータ23A~23Cの出力電圧を一律に350Vに設定したとしても、各蓄電池に流入する電流の大きさには多少のばらつきが発生する。各蓄電池に流入する電流の大きさのばらつきがたとえ非常に小さかったとしても、長期間の積み重ねにより各蓄電池の充電率のばらつきは非常に大きくなる。図3は、蓄電池50A~50Cの充電率に多少のばらつきが発生している状態を示している。 Even if the output voltage of the bidirectional DC/DC converters 23A to 23C is uniformly set to 350V as described above, there is some variation in the magnitude of the current flowing into each storage battery. Even if the variation in the magnitude of the current flowing into each storage battery is very small, the variation in the charging rate of each storage battery becomes very large due to the long-term stacking. FIG. 3 shows a state in which the charging rates of the storage batteries 50A to 50C have some variations.
 図4に示すように、蓄電池50A~50Cの充電が進み、1つの蓄電池50A(第1の蓄電池)のSOCが第1の閾値SOCTHよりも大きくなり、他の2つの蓄電池50B,50C(第2の蓄電池)のSOCが第2の閾値SOCTL以上且つ第1の閾値SOCTH以下である場合、電力管理装置60は蓄電池50Aに接続された双方向DC/DCコンバータ23Aの出力電圧を他の2つの双方向DC/DCコンバータ23B,23Cの出力電圧よりも高くする。例えば、双方向DC/DCコンバータ23Aの出力電圧は370V(第2の電圧)に設定され、他の双方向DC/DCコンバータ23B,23Cの出力電圧は350V(第1の電圧)に維持される。 As shown in FIG. 4, the charging of the storage batteries 50A to 50C progresses, the SOC of one storage battery 50A (first storage battery) becomes larger than the first threshold value SOC TH , and the other two storage batteries 50B and 50C (first storage battery). 2) is greater than or equal to the second threshold SOC TL and less than or equal to the first threshold SOC TH , the power management device 60 changes the output voltage of the bidirectional DC/DC converter 23A connected to the storage battery 50A to another value. It is set higher than the output voltage of the two bidirectional DC/ DC converters 23B and 23C. For example, the output voltage of the bidirectional DC/DC converter 23A is set to 370V (second voltage), and the output voltages of the other bidirectional DC/ DC converters 23B and 23C are maintained at 350V (first voltage). ..
 このようにすることで、蓄電池50Aを他の蓄電池50B,50Cよりも充電されにくくして蓄電池50Aが完全に満充電になることを抑制することができ、すべての蓄電池50A~50Cが充放電可能な状態を維持することができる。したがって、自然エネルギー発電装置の発電電力のロスカットによる無駄を防止することができる。また、直流バス10の電圧変動を抑えてシステムダウンを防止することができる。 By doing so, the storage battery 50A is less likely to be charged than the other storage batteries 50B and 50C, and it is possible to prevent the storage battery 50A from being fully charged, and all the storage batteries 50A to 50C can be charged and discharged. It is possible to maintain a good state. Therefore, it is possible to prevent waste of the generated power of the natural energy power generation device due to loss reduction. Further, it is possible to prevent the system from going down by suppressing the voltage fluctuation of the DC bus 10.
 図5に示すように、2つの蓄電池50A,50B(第1の蓄電池)のSOCがともに第1の閾値SOCTHよりも大きくなり、他の1つの蓄電池50C(第2の蓄電池)のSOCが第2の閾値SOCTL以上且つ第1の閾値SOCTH以下である場合、電力管理装置60は蓄電池50A,50Bにそれぞれ接続された双方向DC/DCコンバータ23A,23Bの出力電圧を他の1つの双方向DC/DCコンバータ23Cの出力電圧よりも高くする。例えば、双方向DC/DCコンバータ23A,23Bの出力電圧は370Vに設定され、双方向DC/DCコンバータ23Cの出力電圧は350Vに維持される。 As shown in FIG. 5, the SOCs of the two storage batteries 50A and 50B (first storage battery) both become larger than the first threshold SOC TH , and the SOC of the other storage battery 50C (second storage battery) becomes the first When it is equal to or greater than the threshold value SOC TL of 2 and equal to or less than the first threshold value SOC TH , the power management device 60 sets the output voltage of the bidirectional DC/ DC converters 23A and 23B connected to the storage batteries 50A and 50B to the other one. It is set higher than the output voltage of the DC/DC converter 23C. For example, the output voltage of the bidirectional DC/ DC converters 23A and 23B is set to 370V, and the output voltage of the bidirectional DC/DC converter 23C is maintained at 350V.
 このようにすることで、蓄電池50A,50Bを他の蓄電池50Cよりも充電されにくくして蓄電池50A,50Bが完全に満充電になることを抑制することができ、すべての蓄電池50A~50Cが充放電可能な状態を維持することができる。 By doing so, the storage batteries 50A and 50B are less likely to be charged than the other storage batteries 50C, and it is possible to prevent the storage batteries 50A and 50B from being fully charged, and all the storage batteries 50A to 50C are charged. The dischargeable state can be maintained.
 図6に示すように、3つの蓄電池50A~50CのすべてのSOCが閾値SOCTHを超えた場合には、すべての双方向DC/DCコンバータ23A~23Cの出力電圧を直流バスの基準電圧よりも高い電圧(例えば370V)する。或いは、すべての双方向DC/DCコンバータ23A~23Cの出力電圧を直流バス10の基準電圧(350V)に戻してもよい。さらにすべての蓄電池50A~50Cが満充電になった場合には、電力管理装置60は自然エネルギー発電装置30の発電動作を停止することが好ましい。 As shown in FIG. 6, when all the SOCs of the three storage batteries 50A to 50C exceed the threshold SOC TH , the output voltages of all the bidirectional DC/DC converters 23A to 23C are lower than the reference voltage of the DC bus. A high voltage (for example, 370V) is applied. Alternatively, the output voltages of all the bidirectional DC/DC converters 23A to 23C may be returned to the reference voltage (350V) of the DC bus 10. Further, when all the storage batteries 50A to 50C are fully charged, it is preferable that the power management apparatus 60 stop the power generation operation of the natural energy power generation apparatus 30.
 図7に示すように、蓄電池50A~50Cの放電が進み、1つの蓄電池50A(第1の蓄電池)のSOCが第2の閾値SOCTLよりも小さくなり、他の2つの蓄電池50B,50C(第2の蓄電池)のSOCが第2の閾値SOCTL以上且つ第1の閾値SOCTH以下である場合、電力管理装置60は蓄電池50Aに接続された双方向DC/DCコンバータ23Aの出力電圧を他の2つの双方向DC/DCコンバータ23B,23Cの出力電圧よりも低くする。例えば、双方向DC/DCコンバータ23Aの出力電圧は330V(第3の電圧)に設定され、他の2つの双方向DC/DCコンバータ23B,23Cの出力電圧は350V(第1の電圧)に維持される。 As shown in FIG. 7, the discharge of the storage batteries 50A to 50C progresses, the SOC of one storage battery 50A (first storage battery) becomes smaller than the second threshold SOC TL , and the other two storage batteries 50B and 50C (first storage battery). 2) is greater than or equal to the second threshold SOC TL and less than or equal to the first threshold SOC TH , the power management device 60 changes the output voltage of the bidirectional DC/DC converter 23A connected to the storage battery 50A to another value. It is set lower than the output voltage of the two bidirectional DC/ DC converters 23B and 23C. For example, the output voltage of the bidirectional DC/DC converter 23A is set to 330V (third voltage), and the output voltages of the other two bidirectional DC/ DC converters 23B and 23C are maintained at 350V (first voltage). To be done.
 このようにすることで、空に近づいた蓄電池50Aを他の蓄電池50B,50Cよりも放電されにくくして蓄電池50Aが完全に空になることを抑制することができ、すべての蓄電池50A~50Cが充放電可能な状態を維持することができる。なお2つの蓄電池50B,50CのSOCが第2の閾値SOCTLよりも小さくなった場合には、対応する2つの双方向DC/DCコンバータ23A,23Bの出力電圧を低くすればよい。 By doing so, it is possible to prevent the storage battery 50A that has become nearly empty from being discharged more easily than the other storage batteries 50B and 50C, and to prevent the storage battery 50A from becoming completely empty, and all the storage batteries 50A to 50C are A chargeable/dischargeable state can be maintained. When the SOC of the two storage batteries 50B, 50C becomes smaller than the second threshold SOC TL , the output voltage of the corresponding two bidirectional DC/ DC converters 23A, 23B may be lowered.
 以上説明したように、本実施形態による直流給電システム1は、双方向DC/DCコンバータ23A~23Cを介して直流バス10に接続された複数の蓄電池50A~50Cと、双方向DC/DCコンバータ23A~23Cの動作を制御する電力管理装置60とを備え、電力管理装置60は、蓄電池50A~50Cの充電率に応じて当該蓄電池50A~50Cに接続された双方向DC/DCコンバータ23A~23Cの出力電圧を変化させるので、蓄電池50A~50C間の充電率のばらつきを抑えて蓄電池50全体の充放電能力の低下を防止することができるだけでなく、直流バス10の安定化を図ることができる。 As described above, the DC power supply system 1 according to the present embodiment includes the plurality of storage batteries 50A to 50C connected to the DC bus 10 via the bidirectional DC/DC converters 23A to 23C and the bidirectional DC/DC converter 23A. Power management device 60 for controlling the operations of the storage batteries 50A to 23C. Since the output voltage is changed, it is possible not only to suppress the variation in the charging rate between the storage batteries 50A to 50C and prevent the charging/discharging ability of the entire storage battery 50 from decreasing, but also to stabilize the DC bus 10.
 以上、本発明の好ましい実施形態について説明したが、本発明は、上記の実施形態に限定されることなく、本発明の主旨を逸脱しない範囲で種々の変更が可能であり、それらも本発明の範囲内に包含されるものであることはいうまでもない。 Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. It goes without saying that it is included in the range.
 例えば、上記実施形態においては3つの蓄電池を用いているが、蓄電池の数は2つ以上(複数)であればいくつであってもよい。また上記実施形態においては、1つのSOC閾値に基づいてDC/DCコンバータの出力電圧を2段階(350V→370V)に変化させているが、2つ以上のSOC閾値を用いてDC/DCコンバータの出力電圧を多段階(例えば350V→360V→370V)に変化させることも可能である。 For example, although three storage batteries are used in the above embodiment, the number of storage batteries may be any number as long as it is two or more (a plurality). Further, in the above embodiment, the output voltage of the DC/DC converter is changed in two steps (350 V→370 V) based on one SOC threshold value. However, the DC/DC converter output voltage is changed by using two or more SOC threshold values. It is also possible to change the output voltage in multiple stages (for example, 350V→360V→370V).
1  直流給電システム
10  直流バス
21,21A,21B  DC/DCコンバータ(昇圧コンバータ)
22,21A~21D  DC/DCコンバータ(降圧コンバータ)
23,23A~23C  双方向DC/DCコンバータ
24  AC/DCコンバータ
30  自然エネルギー発電装置
30A  太陽光発電装置
30B  風力発電装置
35  ディーゼル発電機
40,40A~40D  負荷機器
50  蓄電池システム
50A,50B,50C  蓄電池
60  電力管理装置
70  通信ネットワーク
71  管理者端末
1 DC power supply system 10 DC bus 21, 21A, 21B DC/DC converter (step-up converter)
22,21A-21D DC/DC converter (step-down converter)
23, 23A to 23C Bidirectional DC/DC converter 24 AC/DC converter 30 Natural energy power generation device 30A Solar power generation device 30B Wind power generation device 35 Diesel generator 40, 40A to 40D Load device 50 Storage battery system 50A, 50B, 50C Storage battery 60 power management device 70 communication network 71 administrator terminal

Claims (6)

  1.  直流給電の母線となる直流バスと、
     前記直流バスに発電電力を供給する自然エネルギー発電装置と、
     前記直流バスから負荷電力の供給を受ける負荷機器と、
     前記直流バスに接続された複数の双方向DC/DCコンバータと、
     前記複数の双方向DC/DCコンバータのいずれか一つを介して前記直流バスにそれぞれ接続された複数の蓄電池と、
     前記発電電力、前記負荷電力及び前記複数の蓄電池の充電率に基づいて、前記複数の双方向DC/DCコンバータの動作を管理する電力管理装置とを備え、
     前記電力管理装置は、各蓄電池の充電率に応じて各蓄電池に対応する前記双方向DC/DCコンバータの出力電圧を制御することを特徴とする直流給電システム。
    A DC bus that is a bus for DC power supply,
    A natural energy power generator that supplies power to the DC bus,
    A load device that receives load power from the DC bus,
    A plurality of bidirectional DC/DC converters connected to the DC bus;
    A plurality of storage batteries each connected to the DC bus via any one of the plurality of bidirectional DC/DC converters;
    A power management device that manages the operations of the plurality of bidirectional DC/DC converters based on the generated power, the load power, and the charging rates of the plurality of storage batteries;
    The DC power supply system, wherein the power management device controls the output voltage of the bidirectional DC/DC converter corresponding to each storage battery according to the charging rate of each storage battery.
  2.  前記複数の双方向DC/DCコンバータは、第1及び第2のDC/DCコンバータを含み、
     前記複数の蓄電池は、前記第1及び第2のDC/DCコンバータにそれぞれ接続された第1及び第2の蓄電池を含み、
     前記電力管理装置は、
     前記第1及び第2の蓄電池を含むすべての蓄電池の充電率が第1の閾値以下である場合に、前記第1及び第2の双方向DC/DCコンバータを含むすべての双方向DC/DCコンバータの出力電圧を第1の電圧に設定し、
     少なくとも前記第1の蓄電池の充電率が前記第1の閾値よりも大きく、少なくとも前記第2の蓄電池の充電率が前記第1の閾値以下である場合に、前記第1の双方向DC/DCコンバータの出力電圧を前記第1の電圧よりも高い第2の電圧に設定する、請求項1に記載の直流給電システム。
    The plurality of bidirectional DC/DC converters include first and second DC/DC converters,
    The plurality of storage batteries include first and second storage batteries respectively connected to the first and second DC/DC converters,
    The power management device,
    All bidirectional DC/DC converters including the first and second bidirectional DC/DC converters when the charging rates of all the storage batteries including the first and second storage batteries are equal to or lower than a first threshold value. Set the output voltage of the first voltage,
    At least when the charging rate of the first storage battery is larger than the first threshold value and at least the charging rate of the second storage battery is equal to or less than the first threshold value, the first bidirectional DC/DC converter. 2. The DC power supply system according to claim 1, wherein the output voltage of is set to a second voltage higher than the first voltage.
  3.  前記第1の閾値は、前記第1及び第2の蓄電池の最大容量の80%以上95%以下である、請求項2に記載の直流給電システム。 The DC power supply system according to claim 2, wherein the first threshold value is 80% or more and 95% or less of the maximum capacity of the first and second storage batteries.
  4.  前記電力管理装置は、
     前記第1及び第2の蓄電池を含むすべての蓄電池の充電率が前記第1の閾値よりも小さい第2の閾値以上である場合に、前記第1及び第2の双方向DC/DCコンバータを含むすべての双方向DC/DCコンバータの出力電圧を前記第1の電圧に設定し、
     少なくとも前記第1の蓄電池の充電率が前記第2の閾値よりも小さく、少なくとも前記第2の蓄電池の充電率が前記第2の閾値以上である場合に、前記第1の双方向DC/DCコンバータの出力電圧を前記第1の電圧よりも低い第3の電圧に設定する、請求項2又は3に記載の直流給電システム。
    The power management device,
    Including the first and second bidirectional DC/DC converters when the charging rates of all the storage batteries including the first and second storage batteries are greater than or equal to a second threshold value that is smaller than the first threshold value. Set the output voltage of all bidirectional DC/DC converters to the first voltage,
    At least when the charging rate of the first storage battery is smaller than the second threshold value and at least the charging rate of the second storage battery is equal to or higher than the second threshold value, the first bidirectional DC/DC converter. The DC power supply system according to claim 2 or 3, wherein the output voltage is set to a third voltage lower than the first voltage.
  5.  前記第2の閾値は、前記第1及び第2の蓄電池の最大容量の5%以上20%以下である、請求項4に記載の直流給電システム。 The DC power supply system according to claim 4, wherein the second threshold value is 5% or more and 20% or less of a maximum capacity of the first and second storage batteries.
  6.  前記第1の電圧は、前記直流バスの基準電圧である、請求項1乃至5のいずれか一項に記載の直流給電システム。 The DC power supply system according to any one of claims 1 to 5, wherein the first voltage is a reference voltage of the DC bus.
PCT/JP2019/003849 2019-02-04 2019-02-04 Direct-current power supply system WO2020161766A1 (en)

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WO2023162921A1 (en) * 2022-02-25 2023-08-31 本田技研工業株式会社 Power supply device, power supply device control method, program, and storage medium

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JP2015220889A (en) * 2014-05-19 2015-12-07 シャープ株式会社 Power supply system
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US20170093187A1 (en) * 2015-09-24 2017-03-30 Samsung Sdi Co., Ltd. Energy storage system

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