Upper-level power management device, power interchange control method, and power interchange control program

Abstract

To increase power transmission efficiency.SOLUTION: A host power management device 3 includes an acquisition unit 32, an update unit 33, and an output unit 34. The acquisition unit 32 obtains a received power value of power received by a first power supply system that makes a power transmission request, and a power transmission value of power transmitted by a second power supply system that responds to the power transmission request. The update unit 33 updates an object target value based on the received power value and the power transmission value. The object target value includes at least one of a reception power target value of an external bus voltage in a first converter that can bidirectionally convert between the external bus voltage and a first internal bus voltage supplied to a first internal DC bus in the first power supply system, and a power transmission target value of the external bus voltage in a second converter that can bidirectionally convert between the external bus voltage and a second internal bus voltage supplied to a second internal DC bus in the second power supply system. The output unit 34 outputs a first setting instruction for setting the reception power target value to the first converter, and a second setting instruction for setting the power transmission target value to the second converter.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an upper-level power management device, a power interchange control method, and a power interchange control program. [Background technology]

[0002] A power interchange system is known that interchanges power between power grids that supply power using distributed power sources. For example, Patent Document 1 describes a power interchange system that includes a plurality of power transmitting and receiving units and a virtual power transmission network construction device connected to the plurality of power transmitting and receiving units via a communication network. In this power interchange system, the virtual power transmission network construction device creates a power interchange plan between the power transmitting and receiving units, and the power transmitting and receiving unit on the power transmitting side transmits power specified in the power interchange plan over a specified route for a specified period of time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-177686 Summary of the Invention [Problem to be solved by the invention]

[0004] When transmitting power between power transmitting and receiving units (power supply systems), transmission loss occurs. In this technical field, it is desired to reduce the transmission loss and improve the transmission efficiency.

[0005] The present disclosure describes an upper-level power management device, a management method, and a management program that can improve power transmission efficiency. [Means for solving the problem]

[0006] An upper level power management device according to one aspect of the present disclosure is a device that controls power interchange among a plurality of power supply systems that are connected to each other via an external DC bus. The upper power management device includes: an acquisition unit that acquires a received power value, which is a measurement value of power received by a first power supply system among the multiple power supply systems that is making a power transmission request; and a transmitted power value, which is a measurement value of power transmitted by a second power supply system among the multiple power supply systems that is responding to the power transmission request; an update unit that updates, based on the received power value and the transmitted power value, target target values ​​including at least one of: a received power target value, which is a target value of an external bus voltage in a first converter that can convert bidirectionally between an external bus voltage supplied to an external DC bus and a first internal bus voltage supplied to a first internal DC bus that supplies DC power in the first power supply system; and a transmitted power target value, which is a target value of an external bus voltage in a second converter that can convert bidirectionally between the external bus voltage and a second internal bus voltage supplied to a second internal DC bus that supplies DC power in the second power supply system; and an output unit that outputs a first setting command for setting the received power target value in the first converter and a second setting command for setting the transmitted power target value in the second converter.

[0007] A power interchange control method according to another aspect of the present disclosure is a method for controlling power interchange among a plurality of power supply systems connected to each other via an external DC bus. The power interchange control method includes the steps of: acquiring a received power value, which is a measurement value of power received by a first power supply system among the plurality of power supply systems that is making a power transmission request; and acquiring a transmitted power value, which is a measurement value of power transmitted by a second power supply system among the plurality of power supply systems that is responding to the power transmission request; updating target values ​​based on the received power value and the transmitted power value, the target values ​​including at least one of a received power target value, which is a target value of an external bus voltage in a first converter that can convert bidirectionally between an external bus voltage supplied to an external DC bus and a first internal bus voltage supplied to a first internal DC bus that supplies DC power in the first power supply system, and a transmitted power target value, which is a target value of an external bus voltage in a second converter that can convert bidirectionally between the external bus voltage and a second internal bus voltage supplied to a second internal DC bus that supplies DC power in the second power supply system; and outputting a first setting command for setting the received power target value in the first converter and a second setting command for setting the transmitted power target value in the second converter.

[0008] A power interchange control program according to yet another aspect of the present disclosure is a program that causes a computer to operate so as to control power interchange among a plurality of power supply systems that are connected to each other via an external DC bus. The power interchange control program is a program for causing a computer to execute the following steps: acquiring a received power value, which is a measurement value of power received by a first power supply system among the multiple power supply systems that is making a power transmission request, and a transmitted power value, which is a measurement value of power transmitted by a second power supply system among the multiple power supply systems that is responding to the power transmission request; updating target values ​​based on the received power value and the transmitted power value, the target values ​​including at least one of a received power target value, which is a target value of an external bus voltage in a first converter that can convert bidirectionally between an external bus voltage supplied to an external DC bus and a first internal bus voltage supplied to a first internal DC bus that supplies DC power in the first power supply system, and a transmitted power target value, which is a target value of an external bus voltage in a second converter that can convert bidirectionally between the external bus voltage and a second internal bus voltage supplied to a second internal DC bus that supplies DC power in the second power supply system; and outputting a first setting command for setting the received power target value in the first converter and a second setting command for setting the transmitted power target value in the second converter.

[0009] In these higher-level power management devices, power interchange control methods, and power interchange control programs, target values ​​including at least one of a power reception target value of an external bus voltage in a first converter and a power transmission target value of an external bus voltage in a second converter are updated based on a received power value received by a first power supply system making a power transmission request and a transmitted power value transmitted by a second power supply system responding to the power transmission request. When power is transmitted from the second power supply system to the first power supply system via an external DC bus, the power reception target value of the external bus voltage in the first converter and the power transmission target value of the external bus voltage in the second converter can affect power transmission efficiency. Since it can be said that the smaller the received power value is compared to the transmitted power value, the greater the transmission loss, the target value can be updated to reduce the transmission loss by taking the received power value and the transmitted power value into consideration. As a result, power transmission efficiency can be improved.

[0010] In some embodiments, the update unit may calculate the transmission loss based on the received power value and the transmitted power value, and may update the target value so as to reduce the transmission loss. In this case, the transmission loss is reduced, thereby improving the transmission efficiency.

[0011] In some embodiments, the update unit may repeatedly update the target target value. If the transmission loss has decreased compared to the transmission loss in the previous update, the update unit may update the target target value by adding a predetermined value to the target target value while maintaining the sign of the predetermined value. If the transmission loss has increased compared to the transmission loss in the previous update, the update unit may update the target target value by inverting the sign of the predetermined value and adding the inverted predetermined value to the target target value. With this configuration, as long as the transmission loss continues to decrease, the target target value is changed by the predetermined value in the same direction as the previous update. On the other hand, if the transmission loss begins to increase, the target target value is changed by the predetermined value in the opposite direction from the previous update. Therefore, it is possible to search for an extreme value of the target target value within a change range of the target target value at which the transmission loss is minimized.

[0012] In some embodiments, the upper power management device may further include a response unit that responds to the power transmission request. The response unit may select, from among the plurality of power supply systems, a power supply system that has transmitted a power transmission availability response as the second power supply system. In this case, the power supply system that is available for power transmission is selected as the second power supply system, thereby reducing the possibility of a power shortage occurring across the plurality of power supply systems. [Effects of the Invention]

[0013] According to each aspect and embodiment of the present disclosure, it is possible to improve power transmission efficiency. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a power interchange system including a higher-level power management device according to an embodiment. [Figure 2] FIG. 2 is a hardware configuration diagram of a computer that constitutes the upper power management device shown in FIG. [Figure 3] FIG. 3 is a diagram schematically illustrating the configuration of the power supply system shown in FIG. [Figure 4] FIG. 4 is a functional block diagram of the upper power management device shown in FIG. [Figure 5] FIG. 5 is a sequence diagram showing a series of operations of the power interchange system shown in FIG. [Figure 6] FIG. 6 is a sequence diagram showing a series of operations of the power interchange system shown in FIG. [Figure 7] FIG. 7 is a flowchart showing a series of processes in a power interchange control method performed by the upper-level power management device shown in FIG. [Figure 8] FIG. 8 is a flowchart showing in detail the target value update process shown in FIG. [Figure 9] FIG. 9 is a diagram showing the configuration of a power interchange control program recorded on a recording medium. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0016] A power interchange system including an upper power management device according to one embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic configuration diagram of a power interchange system including an upper power management device according to one embodiment. The power interchange system 1 shown in Fig. 1 is a system for mutual supply of DC power (power interchange) between a plurality of power supply systems. Hereinafter, supplying DC power will be referred to as "power transmission," and receiving a supply of DC power will be referred to as "power reception," and these may be collectively referred to as "power transmission and reception" or "power interchange." The power interchange system 1 includes a plurality of power supply systems, an upper power management device 3, and an external DC bus B1.

[0017] In this embodiment, a configuration is illustrated in which the power interchange system 1 includes two power supply systems (power supply system 2A and power supply system 2B). The power supply system 2A and the power supply system 2B are connected to each other via an external DC bus B1. In this case, one of the power supply system 2A and the power supply system 2B supplies power to the other. For example, when the amount of stored power in the power supply system 2A (the amount of stored power will be described later) is surplus and the amount of stored power in the power supply system 2B is insufficient, the power supply system 2A supplies power to the power supply system 2B via the external DC bus B1. Details of the power supply systems 2A and 2B will be described later.

[0018] The external DC bus B1 is a bus that functions as a bus for supplying DC power between the power supply system 2A and the power supply system 2B. An external bus voltage Vbus1 is supplied to the external DC bus B1. The external bus voltage Vbus1 is a high-voltage DC voltage. The external bus voltage Vbus1 is, for example, a voltage of DC (Direct Current) 350V or more and DC 410V or less. The voltage value of the external bus voltage Vbus1 is set by the power supply system 2A or the power supply system 2B.

[0019] The upper power management device 3 is a device that controls power interchange between multiple power supply systems (in this embodiment, power supply system 2A and power supply system 2B). The upper power management device 3 is communicably connected to the power supply system 2A and the power supply system 2B via a communication network NW. The communication network NW may be configured as either a wired or wireless network. Examples of the communication network NW include the Internet, a WAN (Wide Area Network), and a mobile communication network. The upper power management device 3 may be configured as a single computer 100 (see FIG. 2). The upper power management device 3 may be configured as a plurality of computers 100, as in cloud computing.

[0020] Fig. 2 is a hardware configuration diagram of a computer that constitutes the upper power management device shown in Fig. 1. As shown in Fig. 2, the computer 100 physically includes hardware such as a processor 101, a memory 102, and a communication interface 103.

[0021] An example of the processor 101 is a CPU (Central Processing Unit). The memory 102 can include a main storage device and an auxiliary storage device. The main storage device is composed of RAM (Random Access Memory) and ROM (Read Only Memory), etc. Examples of the auxiliary storage device are semiconductor memory and a hard disk drive. The communication interface 103 is a device that transmits and receives data to and from other devices. The communication interface 103 is composed of, for example, a communication module, a network interface card (NIC), or a wireless communication module that conforms to communication standards such as RS-232C, RS-485, and CAN (Controller Area Network).

[0022] The processor 101 reads and executes the power interchange control program PR (see FIG. 9) stored in the memory 102, causing each piece of hardware to operate under the control of the processor 101, and reading and writing data from and to the memory 102. In this way, each functional unit of the upper-level power management device 3 shown in FIG. 4 is realized.

[0023] Next, power supply systems 2A and 2B will be described with reference to FIG. 3. FIG. 3 is a configuration diagram that schematically illustrates the power supply system illustrated in FIG. 1. Since power supply system 2B has a configuration similar to that of power supply system 2A, only power supply system 2A will be described here. As illustrated in FIG. 3, power supply system 2A is a system that supplies load power WL (load voltage VL) to load device L. In this embodiment, power supply system 2A is a DC power supply system. Load device L may be a DC load device that operates on a DC voltage, or an AC load device that operates on an AC voltage. Examples of DC load devices include LED (Light Emission Diode) lighting fixtures, DC fans, televisions, and personal computers. Examples of AC load devices include washing machines, refrigerators, and air conditioners. Power supply system 2A mutually supplies power (power interchange) with power supply system 2B via an external DC bus B1.

[0024] The power supply system 2A includes a power supply device 5, an auxiliary power supply device 6, a converter 7, a power storage device 8, a bidirectional DC / DC converter 9, a power management device 10, and an internal DC bus B2 (first internal DC bus, second internal DC bus).

[0025] The internal DC bus B2 functions as a bus for DC power supply that supplies DC power within the power supply system 2A. The internal DC bus B2 is laid across the installation locations of the power supply device 5, the auxiliary power supply device 6, the converter 7, and the power storage device 8. An internal bus voltage Vbus2 (first internal bus voltage, second internal bus voltage) is supplied to the internal DC bus B2. The internal bus voltage Vbus2 is a high DC voltage. The internal bus voltage Vbus2 is set to be within the range of the input voltage of the converter 7. The internal bus voltage Vbus2 is, for example, a voltage between DC 240 V and DC 300 V. The value of the internal bus voltage Vbus2 may be fixed or variable. Note that the values ​​of the external bus voltage Vbus1 and the internal bus voltage Vbus2 are not limited to the above examples. The value of the external bus voltage Vbus1 and the value of the internal bus voltage Vbus2 may be the same value, or the value of the internal bus voltage Vbus2 may be higher than the value of the external bus voltage Vbus1.

[0026] The power supply device 5 is a device that supplies power to the internal DC bus B2. In this embodiment, the power supply system 2A includes one power supply device 5. The number of power supply devices 5 is not limited to one and can be changed appropriately as needed. The power supply device 5 includes a renewable energy power generation device 51 and a power conditioner 52.

[0027] The renewable energy power generation device 51 is a device that generates power Wre. Examples of the renewable energy power generation device 51 include a solar power generation device, a wind power generation device, a hydroelectric power generation device, and a geothermal power generation device. The renewable energy power generation device 51 is connected to the internal DC bus B2 via a power conditioner 52. The renewable energy power generation device 51 generates a power generation voltage Vre of a predetermined voltage value and outputs power generation Wre corresponding to the power generation voltage Vre. The power generation voltage Vre may be a DC voltage or an AC voltage.

[0028] The power conditioner 52 is connected to the internal DC bus B2 and is a device that converts the generated voltage Vre into the internal bus voltage Vbus2. The power conditioner 52 is provided between the renewable energy power generation device 51 and the internal DC bus B2. When the generated voltage Vre is a DC voltage, the power conditioner 52 includes a DC / DC converter. When the generated voltage Vre is an AC voltage, the power conditioner 52 includes an AC (Alternating Current) / DC converter. The power conditioner 52 operates, for example, with a DC voltage generated internally based on the internal bus voltage Vbus2. The power conditioner 52 controls the generated power Wre by controlling the power generation operation of the renewable energy power generation device 51 based on a command from the power management device 10.

[0029] When power conditioner 52 receives a start command from power management device 10, it converts generated power voltage Vre into internal bus voltage Vbus2 and supplies internal bus voltage Vbus2 to internal DC bus B2, thereby supplying generated power Wre to internal DC bus B2. When power conditioner 52 receives a stop command from power management device 10, it stops supplying generated power Wre.

[0030] The power conditioner 52 has a power measurement function of measuring the generated power Wre supplied from the renewable energy power generation device 51 to the internal DC bus B2. The power conditioner 52 measures the generated power Wre, for example, periodically. The power conditioner 52 transmits the measurement value of the generated power Wre to the power management device 10.

[0031] The auxiliary power supply 6 is a device that supplies power to the internal DC bus B2. The auxiliary power supply 6 includes a commercial power supply 61 and an AC / DC converter 62. The commercial power supply 61 supplies system power Ws including a system voltage Vs. The system voltage Vs is an AC voltage. The commercial power supply 61 is connected to the internal DC bus B2 via the AC / DC converter 62.

[0032] The AC / DC converter 62 is connected to the internal DC bus B2 and is a device that converts the system voltage Vs into an internal bus voltage Vbus2. The AC / DC converter 62 is provided between the commercial power supply 61 and the internal DC bus B2. The AC / DC converter 62 operates, for example, on a DC voltage that is internally generated based on the system voltage Vs. When a start command is received from the power management device 10, the AC / DC converter 62 converts the system voltage Vs into the internal bus voltage Vbus2 and supplies the internal bus voltage Vbus2 to the internal DC bus B2, thereby supplying system power Ws to the internal DC bus B2. When a stop command is received from the power management device 10, the AC / DC converter 62 stops supplying the system power Ws.

[0033] The AC / DC converter 62 has a power measurement function of measuring the grid power Ws supplied from the commercial power supply 61 to the internal DC bus B2. The AC / DC converter 62 measures the grid power Ws, for example, periodically. The AC / DC converter 62 transmits the measurement value of the grid power Ws to the power management device 10.

[0034] The auxiliary power supply device 6 is capable of supplying power stably, and is controlled to supply power when there is a power shortage in the entire power supply system 2A. In order to maintain the power supply system 2A, the grid power Ws is equal to or greater than the sum of the load power WL and the standby power in the power supply system 2A. The standby power includes the power consumption of the power management device 10 and the power consumption of auxiliary devices (relays, fans, small-capacity power supplies, etc., not shown).

[0035] The converter 7 is connected to the internal DC bus B2 and is a device that converts the internal bus voltage Vbus2 into a load voltage VL. The load voltage VL is a voltage supplied to the load device L. The load device L is connected to the internal DC bus B2 via the converter 7. The converter 7 operates on a DC voltage that is internally generated based on the internal bus voltage Vbus2, for example. In this embodiment, the power supply system 2A includes four converters 7. The number of converters 7 is not limited to four and can be changed depending on the number of load devices L.

[0036] When converter 7 receives a start command from power management apparatus 10, it converts internal bus voltage Vbus2 to load voltage VL and supplies load voltage VL (load power WL) to load device L. If load device L is a DC load device, the load voltage VL is a DC voltage and converter 7 is a DC / DC converter. Converter 7 converts, for example, internal bus voltage Vbus2 of 270 V DC to load voltage VL of 24 V DC. If load device L is an AC load device, the load voltage VL is an AC voltage and converter 7 is a DC / AC converter. When converter 7 receives a stop command from power management apparatus 10, it stops supplying load voltage VL (load power WL).

[0037] The converter 7 has a current limiting function that limits the current value of the load current supplied from the internal DC bus B2 to the load device L by an upper limit current value. The upper limit current value is set by the power management device 10. The converter 7 has a power measuring function that measures the load power WL supplied from the internal DC bus B2 to the load device L based on the load voltage VL and the load current. The converter 7 measures the load power WL, for example, periodically. The converter 7 transmits the measured value of the load power WL to the power management device 10.

[0038] The power storage device 8 is a device for storing surplus power generated in the power supply system 2A and supplying a power shortage generated in the power supply system 2A. When the differential power obtained by subtracting the sum of the load powers WL from the sum of the supplied powers is greater than 0, surplus power equal to the magnitude (power value) of the differential power is generated. The supplied power is power supplied to the internal DC bus B2. In this embodiment, the supplied power is generated power Wre and system power Ws. Each power storage device 8 is supplied with power Wc obtained by equally dividing the surplus power according to the number of power storage devices 8 from the internal DC bus B2. When the differential power is less than 0, a power shortage equal to the magnitude of the differential power is generated. Each power storage device 8 releases power Wc obtained by equally dividing the power shortage according to the number of power storage devices 8 to the internal DC bus B2.

[0039] The number of power storage devices 8 is not limited to three and can be changed appropriately as necessary. Each power storage device 8 includes a storage battery 81, a BMU (Battery Management Unit) 82, and a bidirectional DC / DC converter 83.

[0040] The storage battery 81 is a device that can be charged and discharged. The storage battery 81 is connected to the internal DC bus B2 via a bidirectional DC / DC converter 83. Examples of the storage battery 81 include a lithium ion battery, a sodium-sulfur (NAS) battery, a redox flow battery, a lead-acid battery, and a nickel-metal hydride battery. In this embodiment, the storage batteries 81 included in the multiple power storage devices 8 are of the same type and have the same storage capacity. The storage capacity is the maximum amount of electricity that can be stored. The storage batteries 81 included in the multiple power storage devices 8 may be of different types and may have different storage capacities. The storage battery 81 includes, for example, a plurality of battery cells.

[0041] The BMU 82 is a device that manages the storage battery 81. The BMU 82 has a function of measuring the battery voltage Vbat of the storage battery 81 and a function of measuring the current value of the charge / discharge current of the storage battery 81 to calculate the SOC (State of charge: remaining capacity). The BMU 82 may further have a function of measuring the cell voltages of multiple battery cells that make up the storage battery 81. The BMU 82 transmits battery information of the storage battery 81 to the power management device 10. The battery information includes, for example, the measured value of the battery voltage Vbat, the current value of the charge / discharge current, the temperature of the storage battery 81, the storage capacity of the storage battery 81, and the SOC. The BMU 82 periodically transmits the battery information to the power management device 10.

[0042] The bidirectional DC / DC converter 83 is connected to the internal DC bus B2 and is a device capable of bidirectionally converting between the internal bus voltage Vbus2 and the battery voltage Vbat. The bidirectional DC / DC converter 83 is provided between the storage battery 81 and the internal DC bus B2. The battery voltage Vbat is the voltage of the storage battery 81. A known bidirectional DC / DC converter can be used as the bidirectional DC / DC converter 83. The bidirectional DC / DC converter 83 operates, for example, on a DC voltage generated internally based on the internal bus voltage Vbus2.

[0043] The bidirectional DC / DC converter 83 is controlled by the power management device 10. Specifically, when the bidirectional DC / DC converter 83 receives a charge command from the power management device 10, it converts the internal bus voltage Vbus2 to the battery voltage Vbat and flows a charging current from the internal DC bus B2 to the storage battery 81. This charges the storage battery 81. When the bidirectional DC / DC converter 83 receives a discharge command from the power management device 10, it converts the battery voltage Vbat to the internal bus voltage Vbus2 and flows a discharging current from the storage battery 81 to the internal DC bus B2. This discharges the storage battery 81. The bidirectional DC / DC converter 83 may charge or discharge the storage battery 81 using a constant current method, or may charge or discharge the storage battery 81 using a constant voltage method.

[0044] When the bidirectional DC / DC converter 83 receives a stop command from the power management device 10, it stops operation and transitions to a sleep state in which power consumption is reduced. When the bidirectional DC / DC converter 83 receives a charge command or a discharge command while in the sleep state, it exits the sleep state and executes a charge process or a discharge process. The bidirectional DC / DC converter 83 has a current limiting function that limits the current values ​​of the charge current supplied to the storage battery 81 and the discharge current discharged from the storage battery 81 to equal to or less than a maximum current value. When the bidirectional DC / DC converter 83 receives a command to set the maximum current value from the power management device 10, it sets the maximum current values ​​of the charge current and the discharge current to the maximum current value specified by the setting command.

[0045] When bidirectional DC / DC converter 83 receives a command to set the target value of internal bus voltage Vbus2 from power management device 10, it sets the target value of internal bus voltage Vbus2 to the target value specified by the command. The target value is a voltage value for maintaining the voltage value of internal bus voltage Vbus2 constant. Bidirectional DC / DC converter 83 has a function of maintaining the voltage value of internal bus voltage Vbus2 at the target value even when power Wc is changed.

[0046] The bidirectional DC / DC converter 83 has a power measurement function for measuring the power Wc. The bidirectional DC / DC converter 83 measures the power Wc, for example, periodically. The bidirectional DC / DC converter 83 transmits the measurement value of the power Wc to the power management apparatus 10.

[0047] The bidirectional DC / DC converter 9 is provided between the external DC bus B1 and the internal DC bus B2 and is a device capable of bidirectionally converting between the external bus voltage Vbus1 and the internal bus voltage Vbus2. A known bidirectional DC / DC converter can be used as the bidirectional DC / DC converter 9. The bidirectional DC / DC converter 9 operates, for example, on a DC voltage generated internally based on the internal bus voltage Vbus2.

[0048] The bidirectional DC / DC converter 9 is controlled by the power management device 10. When the bidirectional DC / DC converter 9 receives a setting command for the target value of the external bus voltage Vbus1 from the power management device 10, it sets the target value of the external bus voltage Vbus1 to the target value specified by the setting command. The target value is a voltage value for keeping the voltage value of the external bus voltage Vbus1 constant.

[0049] When the bidirectional DC / DC converter 9 receives a stop command from the power management device 10, it stops operation and transitions to a sleep state in which power consumption is reduced. When the bidirectional DC / DC converter 9 receives a command to set the set value of the external bus voltage Vbus1 while in the sleep state, it exits the sleep state and executes power transmission and reception processing.

[0050] The bidirectional DC / DC converter 9 has a power measurement function for measuring the power input / output between the bidirectional DC / DC converter 9 and the external DC bus B1. The bidirectional DC / DC converter 9 measures the power, for example, periodically. The bidirectional DC / DC converter 9 transmits the measured power value to the power management device 10.

[0051] The power management device 10 is a device (controller) that manages the entire power supply system 2A. The power management device 10 is also referred to as an EMS (Energy Management System). The power management device 10 is connected to the power supply device 5, the auxiliary power supply device 6, the converter 7, the power storage device 8, and the bidirectional DC / DC converter 9 via communication lines so that they can communicate with each other. The communication lines may be wired or wireless. The power management device 10 is connected to the upper power management device 3 via a communication network NW so that they can communicate with each other. The power management device 10 may perform communication in accordance with standards such as RS-232C, RS-485, CAN, Ethernet (registered trademark), and Wi-Fi (registered trademark).

[0052] The power management apparatus 10 has the same hardware configuration as the upper power management apparatus 3. That is, the power management apparatus 10 may be configured by one computer 100 (see FIG. 2 ) like the upper power management apparatus 3, or may be configured by multiple computers 100 like cloud computing.

[0053] Power management apparatus 10 transmits a start command and a stop command to each of power conditioner 52, AC / DC converter 62, converter 7, bidirectional DC / DC converter 83, and bidirectional DC / DC converter 9. For example, power management apparatus 10 transmits a start command to converter 7 to cause converter 7 to supply load voltage VL. Power management apparatus 10 transmits a stop command to converter 7 to cause converter 7 to stop supplying load voltage VL. The same applies to the other converters.

[0054] The power management apparatus 10 controls the bidirectional DC / DC converter 83 to perform a charge / discharge process for charging / discharging the storage batteries 81. The power management apparatus 10 performs the charge / discharge process according to the differential power. When the total amount of supply power is greater than the total amount of load power WL (when the differential power is greater than 0), the power management apparatus 10 sends a charge command to the bidirectional DC / DC converter 83, causing the storage batteries 81 to store the surplus power, which is the differential power. For example, power obtained by equally dividing the surplus power among the number of storage batteries 81 is stored in each storage battery 81. When the total amount of supply power is less than the total amount of load power WL (when the differential power is less than 0), the power management apparatus 10 sends a discharge command to the bidirectional DC / DC converter 83, causing the storage batteries 81 to release the deficit power. For example, power obtained by equally dividing the deficit power among the number of storage batteries 81 is released from each storage battery 81.

[0055] The power management device 10 transmits a power transmission request, a stop request, a power transmission possible response, and a power transmission impossible response to the upper power management device 3 based on the amount of power stored in the power supply system 2A. The power transmission request is a request to receive power interchange from another power supply system (in this embodiment, the power supply system 2B). The stop request is a request to stop power interchange. The power transmission possible response is a response to the power transmission request notifying that power transmission is possible. The power transmission impossible response is a response to the power transmission request notifying that power transmission is impossible.

[0056] The power management apparatus 10 acquires the amount of stored power in the power supply system 2A, for example, as follows. The power management apparatus 10 receives battery information from each BMU 82 and calculates the SOC of the entire power supply system 2A based on the SOC and storage capacity included in each battery information. For example, the power management apparatus 10 calculates the amount of stored power in each storage battery 81 from the SOC and storage capacity of each storage battery 81, and calculates the SOC of the entire power supply system 2A by dividing the sum of the stored power amounts of all the storage batteries 81 by the sum of the storage capacities of all the storage batteries 81. The power management apparatus 10 then acquires the SOC of the entire power supply system 2A as the amount of stored power in the power supply system 2A. The power management apparatus 10 may also acquire the smallest amount of stored power (SOC) of all the storage batteries 81 as the amount of stored power in the power supply system 2A.

[0057] The power management device 10 transmits a power transmission request to the upper power management device 3 when the amount of stored power in the power supply system 2A is insufficient. For example, when the amount of stored power in the power supply system 2A falls below a power storage threshold Bth1, the power management device 10 determines that the amount of stored power in the power supply system 2A is insufficient, and transmits a power transmission request to the upper power management device 3. The power storage threshold Bth1 is a threshold for determining that the amount of stored power in the power supply system 2A is insufficient and that it is necessary to receive power from another power supply system (in this embodiment, the power supply system 2B). The power storage threshold Bth1 is expressed by, for example, SOC. The power storage threshold Bth1 is set to, for example, 20%.

[0058] When the power management device 10 receives a power transmission request from the upper power management device 3, it determines whether power transmission is possible or not based on the amount of power stored in the power supply system 2A. For example, when the amount of power stored in the power supply system 2A exceeds a power storage threshold Bth2, the power management device 10 determines that power transmission is possible and transmits a power transmission possible response to the upper power management device 3. The power storage threshold Bth2 is a threshold for determining that the amount of power stored in the power supply system 2A is surplus and that power can be transmitted to another power supply system (in this embodiment, the power supply system 2B). The power storage threshold Bth2 is greater than the power storage threshold Bth1. The power storage threshold Bth2 is expressed by, for example, SOC. The power storage threshold Bth2 is set to, for example, 70%. On the other hand, when, for example, the amount of power stored in the power supply system 2A is equal to or less than the power storage threshold Bth2, the power management device 10 determines that power transmission is not possible and transmits a power transmission impossible response to the upper power management device 3.

[0059] When the power supply system 2A is supplied with power from another power supply system (power supply system 2B in this embodiment), the power management device 10 transmits a stop request to the upper power management device 3 in response to the fact that the amount of stored power in the power supply system 2A has reached a sufficient level. For example, when the amount of stored power in the power supply system 2A exceeds a power storage threshold Bth3, the power management device 10 determines that the amount of stored power in the power supply system 2A has reached a sufficient level, and transmits a stop request to the upper power management device 3. The power storage threshold Bth3 is a threshold for determining that the amount of stored power in the power supply system 2A has reached a sufficient level. The power storage threshold Bth3 is a value that is greater than the power storage threshold Bth1 and less than the power storage threshold Bth2. The power storage threshold Bth3 is expressed by, for example, SOC. The power storage threshold Bth3 is set to, for example, 50%.

[0060] When the power supply system 2A is transmitting power to another power supply system (power supply system 2B in this embodiment), the power management device 10 transmits a stop request to the upper power management device 3 in response to a decrease in the amount of stored power in the power supply system 2A. For example, when the amount of stored power in the power supply system 2A falls below a power storage threshold Bth4, the power management device 10 determines that the amount of stored power in the power supply system 2A has decreased, and transmits a stop request to the upper power management device 3. The power storage threshold Bth4 is a threshold for determining that the amount of stored power in the power supply system 2A has decreased and that no more power can be transmitted to the other power supply system (power supply system 2B in this embodiment). The power storage threshold Bth4 is a value greater than the power storage threshold Bth1 and smaller than the power storage threshold Bth2. The power storage threshold Bth4 may be the same value as the power storage threshold Bth3, or may be a different value. The power storage threshold Bth4 is expressed, for example, by SOC. The power storage threshold Bth4 is set to, for example, 50%.

[0061] Next, the functional configuration of the upper power management device 3 will be described with reference to Fig. 4. Fig. 4 is a functional block diagram of the upper power management device shown in Fig. 1. As shown in Fig. 4, the upper power management device 3 functionally includes a response unit 31, an acquisition unit 32, an update unit 33, and an output unit 34.

[0062] The response unit 31 is a functional unit that responds to a power transmission request. When the response unit 31 receives a power transmission request from one power supply system, it transmits the power transmission request to the other power supply systems. The response unit 31 selects a power supply system that has transmitted a power transmission possible response in response to the power transmission request as a power supply system that can transmit power. When the response unit 31 receives a power transmission impossible response in response to the power transmission request from all power supply systems other than the power supply system that is making the power transmission request, it transmits a power transmission impossible response to the power supply system that is making the power transmission request.

[0063] The acquisition unit 32 is a functional unit that acquires a transmitted power value and a received power value. The transmitted power value is a measurement value of power transmitted by a power supply system that is responding to a power transmission request. More specifically, the transmitted power value is a measurement value of power transmitted by the bidirectional DC / DC converter 9 to the external DC bus B1. The received power value is a measurement value of power received by a power supply system that is making a power transmission request. More specifically, the received power value is a measurement value of power received by the bidirectional DC / DC converter 9 via the external DC bus B1.

[0064] The update unit 33 is a functional unit that updates the target value based on the transmission power value and the received power value. The target value is a target value to be updated and includes at least one of the power transmission target value and the power reception target value. The power transmission target value is the target value of the external bus voltage Vbus1 in the bidirectional DC / DC converter 9 of the power supply system that is responding to a power transmission request. The power reception target value is the target value of the external bus voltage Vbus1 in the bidirectional DC / DC converter 9 of the power supply system that is making a power transmission request. The update unit 33 calculates a transmission loss based on the transmission power value and the received power value, and updates the target value based on the transmission loss.

[0065] The output unit 34 is a functional unit that outputs a setting command for setting a power transmission target value to the bidirectional DC / DC converter 9 of a power supply system that is responding to a power transmission request, and a setting command for setting a power reception target value to the bidirectional DC / DC converter 9 of a power supply system that is making a power transmission request. The output unit 34 outputs (transmits) the setting command to the power management device 10 of each power supply system.

[0066] Next, a series of operations of the power interchange system 1 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are sequence diagrams showing an example of a series of operations of the power interchange system shown in Fig. 1. Here, a case where a shortage of stored power occurs in the power supply system 2A (first power supply system) will be described as an example.

[0067] As shown in Figures 5 and 6, first, the power management device 10 of the power supply system 2A (hereinafter, sometimes referred to as "power management device 10A") transmits a power transmission request to the upper power management device 3 (step S1). Then, upon receiving the power transmission request, the upper power management device 3 transmits a power transmission request to the power supply system 2B (second power supply system) (step S2). Then, upon receiving the power transmission request, the power management device 10 of the power supply system 2B (hereinafter, sometimes referred to as "power management device 10B") checks the amount of power stored in the power supply system 2B (step S3).

[0068] Specifically, if the amount of stored power in power supply system 2B exceeds power storage threshold Bth2, power management device 10B transmits a power transmission possible response to upper power management device 3, and if the amount of stored power in power supply system 2B is equal to or less than power storage threshold Bth2, power management device 10B transmits a power transmission impossible response to upper power management device 3. Here, it is assumed that the amount of stored power in power supply system 2B exceeds power storage threshold Bth2. Therefore, power management device 10B transmits a power transmission possible response to upper power management device 3 (step S4).

[0069] Next, upon receiving the power transmission possible response, the upper power management device 3 transmits a setting command to the power supply system 2A to set an initial value (e.g., 350 V) of the power reception target value, and transmits a setting command to the power supply system 2B to set an initial value (e.g., 400 V) of the power transmission target value (step S5). Then, upon receiving the setting commands, the power management device 10A transmits a setting command to the bidirectional DC / DC converter 9 (first converter) of the power supply system 2A, causing the bidirectional DC / DC converter 9 to set the target value of the external bus voltage Vbus1 to the initial value of the power reception target value (step S6). Similarly, upon receiving the setting commands, the power management device 10B transmits a setting command to the bidirectional DC / DC converter 9 (second converter) of the power supply system 2B, causing the bidirectional DC / DC converter 9 to set the target value of the external bus voltage Vbus1 to the initial value of the power transmission target value (step S6). This starts power transmission from the power supply system 2B to the power supply system 2A.

[0070] Next, the bidirectional DC / DC converter 9 of the power supply system 2A measures the received power and transmits the measured value (received power value) to the power management device 10A. The power management device 10A then acquires the received power value from the bidirectional DC / DC converter 9 of the power supply system 2A (step S7) and transmits the received power value to the upper power management device 3 (step S8). Similarly, the bidirectional DC / DC converter 9 of the power supply system 2B measures the transmitted power and transmits the measured value (transmitted power value) to the power management device 10B. The power management device 10B then acquires the transmitted power value from the bidirectional DC / DC converter 9 of the power supply system 2B (step S9) and transmits the transmitted power value to the upper power management device 3 (step S10).

[0071] Next, upon receiving the transmitted power value and the received power value, the upper power management device 3 calculates the transmission loss (step S11). For example, the upper power management device 3 subtracts the received power value from the transmitted power value and calculates the subtraction result as the transmission loss. The upper power management device 3 then updates the target value based on the transmission loss (step S12). Here, the power transmission target value and the power receiving target value are updated as the target values. A method for updating the target values ​​will be described later. The upper power management device 3 then transmits a setting command (first setting command) to set the updated power receiving target value to the power supply system 2A, and transmits a setting command (second setting command) to set the updated power transmission target value to the power supply system 2B (step S13).

[0072] Then, upon receiving the setting command, power management device 10A transmits a setting command to bidirectional DC / DC converter 9 of power supply system 2A, causing bidirectional DC / DC converter 9 to set the target value of external bus voltage Vbus1 to the updated power receiving target value (step S14). Similarly, upon receiving the setting command, power management device 10B transmits a setting command to bidirectional DC / DC converter 9 of power supply system 2B, causing bidirectional DC / DC converter 9 to set the target value of external bus voltage Vbus1 to the updated power transmission target value (step S14). Thereafter, steps S7 to S14 are repeated until upper-level power management device 3 receives a stop request.

[0073] When the power interchange system 1 includes three or more power supply systems, the power interchange system 1 operates in the same manner as the series of operations shown in Fig. 5 and Fig. 6. In this case, in step S2, the upper power management device 3 transmits a power transmission request to all power supply systems included in the power interchange system 1 except for the power supply system that transmitted the power transmission request (is making the power transmission request). Then, in step S5, if the upper power management device 3 receives power transmission capability responses from multiple power supply systems, it transmits a setting command to set an initial value of the power transmission target value to all power supply systems that transmitted the power transmission capability responses. This realizes a configuration in which multiple power supply systems transmit power to one power supply system. The upper power management device 3 repeats the processing from step S2 every time it receives a power transmission request from a power supply system, thereby realizing a configuration in which one or multiple power supply systems transmit power to multiple power supply systems.

[0074] In step S11, the upper power management device 3 calculates the transmission loss by subtracting the sum of the received power values ​​from the sum of the transmitted power values. Then, in step S12, the upper power management device 3 updates the target value based on the transmission loss. Therefore, the target value can be updated even in a configuration in which one or more power supply systems transmit power to one or more power supply systems.

[0075] Next, a generalized series of processes in the power interchange control method performed by the upper power management device 3 will be described with reference to Figures 7 and 8. Figure 7 is a flowchart showing a series of processes in the power interchange control method performed by the upper power management device shown in Figure 1. Figure 8 is a flowchart showing in detail the target value update process shown in Figure 7. The series of processes shown in Figure 7 is started when the upper power management device 3 receives a power transmission request.

[0076] 7, first, the response unit 31 transmits a power transmission request to the power supply system (step S31). For example, the response unit 31 transmits the power transmission request to all power supply systems included in the power interchange system 1 except for the power supply system that transmitted the power transmission request (is making the power transmission request). Then, the response unit 31 receives a power transmission possible response or a power transmission impossible response from each power supply system (the power management device 10 thereof) in response to the power transmission request.

[0077] Next, the response unit 31 determines whether or not there is a power supply system available to transmit power in the power interchange system 1 (step S32). For example, when the response unit 31 receives a power transmission possible response from at least one power supply system, it determines that there is a power supply system available to transmit power in the power interchange system 1. When the response unit 31 receives a power transmission impossible response from all power supply systems, it determines that there is no power supply system available to transmit power in the power interchange system 1. If it is determined in step S32 that there is no power supply system available to transmit power in the power interchange system 1 (step S32: NO), the response unit 31 transmits a power transmission impossible response to the power supply system that is making the power transmission request (step S33), and the series of processes shown in FIG. 7 ends.

[0078] On the other hand, if it is determined in step S32 that a power supply system capable of transmitting power exists in the power interchange system 1 (step S32: YES), the response unit 31 transmits a setting command for setting an initial value of the power receiving target value to the power supply system making the power transmission request, and transmits setting commands for setting initial values ​​of the power transmission target value to all power supply systems capable of transmitting power (step S34). Note that the initial values ​​of the power transmission target value and the initial values ​​of the power receiving target value are set in advance and stored in a memory (not shown).

[0079] Then, when each power supply system (power management device 10 thereof) receives the setting command, the target value of the external bus voltage Vbus1 in the bidirectional DC / DC converter 9 of the power supply system making the power transmission request is set to the initial value of the power reception target value, and the target value of the external bus voltage Vbus1 in the bidirectional DC / DC converter 9 of the power supply system that can transmit power is set to the initial value of the power transmission target value. This starts power transmission from the power supply system that can transmit power to the power supply system that is making the power transmission request. That is, power interchange starts between the power supply systems.

[0080] Next, the upper power management device 3 performs a target value update process (step S35). In the target value update process of step S35, as shown in FIG. 8, first, the acquisition unit 32 acquires a transmitted power value and a received power value (step S51). Specifically, the acquisition unit 32 receives a transmitted power value from (the power management device 10 of) the power supply system that is transmitting power, and receives a received power value from (the power management device 10 of) the power supply system that is receiving power. Then, the acquisition unit 32 outputs the transmitted power value and the received power value to the update unit 33.

[0081] Next, the update unit 33 calculates the transmission loss (step S52). In step S52, upon receiving the transmitted power values ​​and received power values, the update unit 33 calculates the transmission loss based on the transmitted power values ​​and received power values. Specifically, the update unit 33 subtracts the sum of the received power values ​​from the sum of the transmitted power values, and calculates the subtraction result as the transmission loss. The update unit 33 then stores (information indicating) the transmission loss in a memory (not shown) (step S53).

[0082] Next, the update unit 33 determines whether the transmission loss has increased (step S54). In step S54, the update unit 33 compares the transmission loss calculated in step S52 (the current transmission loss) with the previous transmission loss stored in memory, and determines whether the transmission loss has increased. If the current transmission loss is greater than the previous transmission loss, the update unit 33 determines that the transmission loss has increased (step S54: YES) and inverts the sign of the predetermined value (step S55). The predetermined value is a value that specifies the amount of increase or decrease (fluctuation) of the target target value in one target value update process. In other words, the target target value is increased or decreased by the predetermined value in one target value update process. From the viewpoint of control voltage accuracy, the predetermined value may be 1 V or more. The predetermined value is set, for example, to approximately 1 V to 10 V. Here, the predetermined value is set to approximately 2 V. As the amount of change in the transmission loss due to an increase or decrease by the predetermined value becomes smaller, the predetermined value may be decreased in stages.

[0083] The target target value includes at least one of the power transmission target value and the power receiving target value. When the target target value includes the power transmission target value and the power receiving target value, that is, when both the power transmission target value and the power receiving target value are updated, different predetermined values ​​may be used for the power transmission target value and the power receiving target value, or the same predetermined value may be used. In this case, the sign of the predetermined value for the power transmission target value and the sign of the predetermined value for the power receiving target value are the same.

[0084] On the other hand, in step S54, if the current transmission loss is equal to or less than the previous transmission loss, the update unit 33 determines that the transmission loss has not increased (step S54: NO), and maintains the sign of the predetermined value.

[0085] Next, the update unit 33 adds a predetermined value to the target target value (step S56). Here, if it is determined in step S54 that the transmission loss has not increased, the sign of the predetermined value is maintained, so whether the target target value is increased or decreased is the same as in the previous target value update process. In other words, if the target target value was decreased in the previous target value update process, the target target value is also decreased in the current target value update process. On the other hand, if it is determined in step S54 that the transmission loss has increased, the sign of the predetermined value is inverted, so whether the target target value is increased or decreased is different from the previous target value update process. In other words, if the target target value was decreased in the previous target value update process, the target target value is increased in the current target value update process. Then, the update unit 33 outputs the updated target target value to the output unit 34.

[0086] Next, the output unit 34 transmits a setting command (step S57). In step S57, upon receiving the updated target target value, the output unit 34 generates a setting command for setting the updated target target value. Then, the output unit 34 transmits the setting command to the power supply system including the bidirectional DC / DC converter 9 for which the target target value has been set. For example, if the target target value is a power transmission target value and a power reception target value, the output unit 34 transmits a setting command for setting the updated power reception target value to the power supply system receiving power, and transmits a setting command for setting the updated power transmission target value to the power supply system transmitting power. Then, when each power supply system receives the setting command, the target value of the external bus voltage Vbus1 in the bidirectional DC / DC converter 9 is set to the updated target target value.

[0087] This completes the target value update process in step S35.

[0088] Next, the response unit 31 determines whether or not a stop request has been received from any of the power supply systems participating in the power interchange (step S36). If the response unit 31 has not received a stop request from any of the power supply systems participating in the power interchange (step S36: NO), step S35 is performed again. On the other hand, if the response unit 31 has received a stop request from any of the power supply systems participating in the power interchange (step S36: YES), the response unit 31 transmits a stop command to the power supply system to stop the power interchange (step S37). Then, upon receiving the stop command, the power supply system that transmitted the stop request stops the bidirectional DC / DC converter 9.

[0089] Next, the response unit 31 determines whether or not it is possible to continue the power interchange (step S38). For example, if both a power supply system transmitting power and a power supply system receiving power exist, the response unit 31 determines that it is possible to continue the power interchange. If at least one of a power supply system transmitting power and a power supply system receiving power does not exist, the response unit 31 determines that it is not possible to continue the power interchange. If it is determined in step S38 that it is possible to continue the power interchange (step S38: YES), step S35 is performed again. On the other hand, if it is determined in step S38 that it is not possible to continue the power interchange (step S38: NO), the response unit 31 outputs a stop command to all power supply systems participating in the power interchange and stops the power interchange (step S39).

[0090] This completes the series of processes shown in FIG.

[0091] Next, a power interchange control program PR for causing the computer 100 to function as the higher-level power management device 3 and a recording medium MD for recording the power interchange control program PR will be described with reference to Fig. 9. Fig. 9 is a diagram showing the configuration of the power interchange control program recorded on the recording medium.

[0092] 9, the power interchange control program PR includes a main module P30, a response module P31, an acquisition module P32, an update module P33, and an output module P34. The main module P30 is a part that performs overall control of processing related to the upper power management device 3. The functions realized by executing the response module P31, the acquisition module P32, the update module P33, and the output module P34 are similar to the functions of the response unit 31, the acquisition unit 32, the update unit 33, and the output unit 34 in the above embodiment, respectively.

[0093] The power interchange control program PR is recorded on a recording medium MD. The recording medium MD is a computer-readable non-transitory recording medium. Examples of the recording medium MD include a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), and a semiconductor memory. The power interchange control program PR may be provided as a data signal via a communication network NW.

[0094] In the above-described upper-level power management device 3, power interchange control method, and power interchange control program PR, the target value is updated based on the received power value received by a power supply system making a power transmission request and the transmitted power value transmitted by a power supply system responding to the power transmission request. For example, when power is transmitted (power interchanged) from one power supply system to another power supply system via an external DC bus B1, the transmission target value of the external bus voltage Vbus1 in the bidirectional DC / DC converter 9 of the power supply system and the receiving target value of the external bus voltage Vbus1 in the bidirectional DC / DC converter 9 of the other power supply system can affect the power transmission efficiency. Therefore, the smaller the received power value is compared to the transmitted power value, the greater the transmission loss. Therefore, by taking the received power value and transmitted power value into consideration, the target value can be updated to reduce the transmission loss. As a result, the power transmission efficiency can be improved.

[0095] Specifically, the update unit 33 calculates the transmission loss based on the received power value and the transmitted power value, and updates the target value so as to reduce the transmission loss. With this configuration, the transmission loss is reduced, and therefore it is possible to improve the transmission efficiency.

[0096] More specifically, the update unit 33 repeatedly updates the target value. Then, if the transmission loss has decreased compared to the transmission loss in the previous target value update process, the update unit 33 updates the target target value by adding a predetermined value to the target target value while maintaining the sign of the predetermined value. If the transmission loss has increased compared to the transmission loss in the previous target value update process, the update unit 33 updates the target target value by inverting the sign of the predetermined value and adding the inverted predetermined value to the target target value. With this configuration, as long as the transmission loss continues to decrease, the target target value is changed by the predetermined value in the same direction as in the previous target value update process. For example, if the target target value was decreased in the previous target value update process, the target target value is also decreased in the current target value update process. On the other hand, if the transmission loss begins to increase, the target target value is changed by the predetermined value in the opposite direction to the previous update. If the target target value was decreased in the previous target value update process, the target target value is increased in the current target value update process. Therefore, it is possible to search for the extreme value of the target value that minimizes the transmission loss within the range of change of the target value.

[0097] The response unit 31 selects, from among the plurality of power supply systems, a power supply system that has transmitted a power transmission availability response as a power supply system that can transmit power. The power supply system that has transmitted the power transmission availability response has a surplus of stored power and can transmit power to another power supply system. By transmitting power from such a power supply system to the power supply system that has made the power transmission request, the possibility of a power shortage occurring in the power interchange system 1 as a whole can be reduced.

[0098] The upper level power management device, the power interchange control method, and the power interchange control program according to the present disclosure are not limited to the above-described embodiments.

[0099] At least one of power conditioner 52, AC / DC converter 62, converter 7, bidirectional DC / DC converter 83, and bidirectional DC / DC converter 9 may not have a power measurement function. In this case, power management device 10 may obtain the measurement value of each power from the measurement value of the voltage measured by the voltage sensor and the measurement value of the current measured by the current sensor.

[0100] The power supply device 5 may include another power generation device instead of the renewable energy power generation device 51.

[0101] The auxiliary power supply 6 may include a power generation device instead of the commercial power supply 61. An example of a power generation device is a diesel generator. In this case, the number of auxiliary power supplies 6 is not limited to one and can be changed appropriately as needed. When the auxiliary power supply 6 does not include the commercial power supply 61, the power supply systems 2A and 2B are also referred to as independent DC power supply systems. The auxiliary power supply 6 may be used only when the power supply systems 2A and 2B are started up. For example, when a power shortage occurs in the power supply system 2A, the power supply system 2A may first receive power from the power supply system 2B, and if power cannot be supplied from the power supply system 2B, the power supply system 2A may receive power from the auxiliary power supply 6.

[0102] In the above embodiment, each of the power conditioner 52, the AC / DC converter 62, the converter 7, the bidirectional DC / DC converter 83, and the bidirectional DC / DC converter 9 operates on a DC voltage generated within the device. Instead of this configuration, each of the power supply systems 2A and 2B may include a power supply unit, and the power supply unit may generate a DC voltage having a constant voltage value from the internal bus voltage Vbus2 of the internal DC bus B2 and supply the DC voltage (power) to each device.

[0103] The power supply system 2A does not have to include the renewable energy power generation device 51. In this case, the renewable energy power generation device 51 provided outside the power supply system 2A may be connected to the internal DC bus B2 via a power conditioner 52 included in the power supply system 2A.

[0104] The power supply system 2A does not necessarily have to include the commercial power supply 61. In this case, the commercial power supply 61 provided outside the power supply system 2A may be connected to the internal DC bus B2 via an AC / DC converter 62 included in the power supply system 2A.

[0105] As described above, in the target value update process, both the power transmission target value and the power receiving target value may be updated, or only one of them may be updated. For example, the power receiving target value may be set to a predetermined fixed value, and only the power transmission target value may be updated. Alternatively, the power transmission target value may be set to a predetermined fixed value, and only the power receiving target value may be updated.

[0106] The target value may be updated by a method different from that of the above embodiment. For example, a plurality of combinations of the power transmission target value and the power receiving target value may be prepared in advance, and these combinations may be used in order to search for a combination that minimizes the power transmission loss. [Explanation of symbols]

[0107] 1...power interchange system, 2A...power supply system (first power supply system), 2B...power supply system (second power supply system), 3...upper power management device, 9...bidirectional DC / DC converter (first converter, second converter), 10, 10A, 10B...power management device, 31...response unit, 32...acquisition unit, 33...update unit, 34...output unit, 100...computer, B1...external DC bus, B2...internal DC bus (first internal DC bus, second internal DC bus), MD...recording medium, PR...power interchange control program.

Claims

1. An upper power management device that controls power interchange between a plurality of power supply systems that are connected to each other via an external DC bus, an acquisition unit that acquires a received power value that is a measurement value of power received by a first power supply system that is making a power transmission request among the plurality of power supply systems, and a transmitted power value that is a measurement value of power transmitted by a second power supply system that is responding to the power transmission request among the plurality of power supply systems; an updating unit that updates target values ​​based on the received power value and the transmitted power value, the target values ​​including at least one of a power receiving target value that is a target value of an external bus voltage in a first converter that can convert bidirectionally between an external bus voltage supplied to the external DC bus and a first internal bus voltage supplied to a first internal DC bus that supplies DC power in the first power supply system, and a power transmitting target value that is a target value of an external bus voltage in a second converter that can convert bidirectionally between the external bus voltage and a second internal bus voltage that is supplied to a second internal DC bus that supplies DC power in the second power supply system; an output unit that outputs a first setting command for setting the power receiving target value in the first converter and a second setting command for setting the power transmission target value in the second converter; An upper power management device comprising:

2. The upper power management device according to claim 1 , wherein the update unit calculates a transmission loss based on the received power value and the transmitted power value, and updates the target value so that the transmission loss decreases.

3. The update unit repeatedly updates the target value, 3. The upper power management device of claim 2, wherein the update unit updates the target target value by adding the specified value to the target target value while maintaining the sign of the specified value when the transmission loss has decreased compared to the transmission loss in the previous update, and updates the target target value by inverting the sign of the specified value and adding the specified value with the inverted sign to the target target value when the transmission loss has increased compared to the transmission loss in the previous update.

4. a response unit that responds to the power transmission request, 4. The upper power management device according to claim 1, wherein the response unit selects, from among the plurality of power supply systems, a power supply system that has transmitted a power transmission availability response as the second power supply system.

5. A power interchange control method for controlling power interchange between a plurality of power supply systems connected to each other via an external DC bus, comprising: acquiring a received power value that is a measurement value of power received by a first power supply system that is making a power transmission request among the plurality of power supply systems, and a transmitted power value that is a measurement value of power transmitted by a second power supply system that is responding to the power transmission request among the plurality of power supply systems; updating target values ​​based on the received power value and the transmitted power value, the target values ​​including at least one of a power receiving target value, which is a target value of the external bus voltage in a first converter capable of bidirectionally converting between an external bus voltage supplied to the external DC bus and a first internal bus voltage supplied to a first internal DC bus that supplies DC power in the first power supply system, and a power transmitting target value, which is a target value of the external bus voltage in a second converter capable of bidirectionally converting between the external bus voltage and a second internal bus voltage supplied to a second internal DC bus that supplies DC power in the second power supply system; outputting a first setting command for setting the power receiving target value in the first converter and a second setting command for setting the power transmission target value in the second converter; A power interchange control method comprising:

6. A power interchange control program that causes a computer to operate to control power interchange among a plurality of power supply systems that are connected to each other via an external DC bus, comprising: acquiring a received power value that is a measurement value of power received by a first power supply system that is making a power transmission request among the plurality of power supply systems, and a transmitted power value that is a measurement value of power transmitted by a second power supply system that is responding to the power transmission request among the plurality of power supply systems; updating target values ​​based on the received power value and the transmitted power value, the target values ​​including at least one of a power receiving target value, which is a target value of the external bus voltage in a first converter capable of bidirectionally converting between an external bus voltage supplied to the external DC bus and a first internal bus voltage supplied to a first internal DC bus that supplies DC power in the first power supply system, and a power transmitting target value, which is a target value of the external bus voltage in a second converter capable of bidirectionally converting between the external bus voltage and a second internal bus voltage supplied to a second internal DC bus that supplies DC power in the second power supply system; outputting a first setting command for setting the power receiving target value in the first converter and a second setting command for setting the power transmission target value in the second converter; A power interchange control program for causing a computer to execute the above.

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