Power management device and power management system

Abstract

Provided are a power management device and a power management system capable of stably maintaining a supply and demand balance of power. This power management system comprises a plurality of power management devices, and a plurality of apparatuses connected to the plurality of power management devices and functioning as a load, a generator, or a capacitor. The power management device includes: three or more power input / output ports configured to be connectable between the apparatus and another power management device via wiring; and a switch unit that switchably connects two power input / output ports among the power input / output ports and transmits power between the two power input / output ports connected to each other. The power management device generates supply and demand information including the magnitude of the required power consumption and the power shortage rate for the apparatus connected to the power management device, or the magnitude of the suppliable power and the surplus rate of the power, and the price information presented regarding the purchase or sale of the power, and transmits the supply and demand information to the other power management device each prescribed unit time.

Description

Power management device and power management system

[0001] The present invention relates to an electric power supply and demand management technique for managing the supply and consumption of electric power.

[0002] Conventionally, electricity consumed in urban areas is generated at power plants located in areas far from urban areas, such as mountainous or coastal regions, where the voltage is converted and the electricity is transmitted to urban areas via transmission lines. It is said that the power loss caused by transmission can be quite large, for example, when transmitting electricity from mountainous regions to urban areas.

[0003] On the other hand, in recent years, various power generation devices such as solar power generation and small-scale hydroelectric power generation have been commercialized for ordinary households and small businesses. In addition, the recent liberalization of the electricity retail market has led to many businesses entering the power generation business. In this way, there are a wide range of options for procuring electricity other than receiving electricity from the traditional major power companies.

[0004] The amount of electricity consumed in ordinary households and many businesses is monitored by a power meter installed in each home. The electricity charges for ordinary households and small businesses are usually set based on the peak value of electricity consumption within a specified period (e.g., one day) based on the monitored value of the power meter, and are billed to the electric power company.

[0005] As a technology related to charging for power consumption, Patent Literature 1 discloses a power supply method for charging for the supply of power to each device. In this power supply method, the device transmits a power supply request, a power supply station receives the power supply request, and the power supply station that has received the power supply request starts transmitting a power packet. When the power supply station starts transmitting the power packet, the device starts receiving the power packet. The device and the power supply station receive and transmit the power-routed power packet, respectively. The power supply request includes a power supply destination address in the power routing, and the power supply station adds the power supply destination address included in the power supply request to the power packet.

[0006] International Publication No. 2012 / 081312

[0007] Considering the power loss mentioned above, in order to shorten the transmission distance as much as possible, it is conceivable to generate electricity in-house or to share the generated electricity among neighboring power users. In this case, neighboring power users can be both power suppliers and consumers. In order to maintain a system in which power can be shared among users, it is important to maintain a stable balance between supply and demand in the system.

[0008] The present invention has been made in view of the above, and has an object to provide a power management device and a power management system that can stably maintain the balance between power supply and demand.

[0009] In order to solve the above-described problems, a power management device according to one aspect of the present invention is a power management device that relays power transmission between a plurality of devices that function as either power loads, generators, or power storage devices in a power management system, and includes three or more power input / output ports that are configured to be connectable via wiring between the devices that function as either power loads, generators, or power storage devices and other power management devices; a switch unit that switchably connects two of the three or more power input / output ports and transmits power between the two connected power input / output ports; a memory unit that stores device identification information that is individually assigned to the power management device; and a storage unit that stores device identification information that is individually assigned to the power management device and other power management devices that are connected to the power management device. a supply and demand information generation unit configured to generate power supply and demand information for the equipment connected to the power management device, the supply and demand information including the amount of required power consumption and the power shortage rate, or the amount of power that can be supplied and the power surplus rate, and price information presented for purchasing or selling power, and to cause the power management device to transmit the supply and demand information to another power management device connected to the power management device at every predetermined unit time; and a selection unit configured to determine, based on the supply and demand information received from the other power management devices, which two of the three or more power input / output ports to be connected to each other at every predetermined unit time.

[0010] The power management device may further include a power measurement unit configured to measure the direction and amount of power transmitted between two interconnected power input / output ports at the specified unit time, and a power information generation unit configured to generate power information including the direction and amount of power measured by the power measurement unit, price information included in the supply and demand information transmitted to or received from another power management device connected to one of the two interconnected power input / output ports, and device identification information of the other power management device, wherein the memory unit may further store user identification information assigned to each user of the power management device, and the communication unit may be configured to link the power information generated by the power information generation unit to the user identification information assigned to the power management device and transmit it to a communication network.

[0011] In the above-mentioned power management device, when an apparatus that functions as a load is connected to the power management device, the selection unit may select, based on the supply and demand information received from another power management transmission, a power input / output port to which another power management device with the highest surplus rate of power is connected, as one of the two power input / output ports to be connected to each other.

[0012] In the above-mentioned power management device, when an apparatus that functions as a generator is connected to the power management device, the selection unit may select, based on the supply and demand information received from the other power management device, the power input / output port to which the other power management device with the highest power shortage rate is connected as one of the two power input / output ports to be connected to each other.

[0013] In the above-mentioned power management device, when an apparatus that functions as a power storage device is connected to the power management device, when the apparatus is in a power storage mode, the selection unit may select, based on the supply and demand information received from the other power management device, the power input / output port to which the other power management device with the highest power surplus rate is connected as one of the two power input / output ports to be connected to each other, and when the apparatus is in a discharge mode, the selection unit may select, based on the supply and demand information received from the other power management device, the power input / output port to which the other power management device with the highest power shortage rate is connected as one of the two power input / output ports to be connected to each other.

[0014] In the above-mentioned power management device, when the selection unit receives the supply and demand information from another power management device, it may select one of the two power input / output ports to be connected to each other based on price information contained in the supply and demand information.

[0015] In the above power management device, the supply and demand information generating unit may adjust the price information according to the amount of required power consumption and the power shortage rate, or the amount of power that can be supplied and the power surplus rate.

[0016] In the above-mentioned power management device, the supply and demand information generation unit may change the price information so as to raise the purchase price of electricity when a device functioning as a load is connected to the power management device and the power shortage rate does not change for a specified period of time, and may change the price information so as to lower the selling price of electricity when a device functioning as a generator is connected to the power management device and the power surplus rate does not change for a specified period of time.

[0017] In the power management device, the supply and demand information may be transmitted and received between other power management devices by power line communication.

[0018] In the power management device, the supply and demand information may be transmitted and received between other power management devices via a communication network.

[0019] Another aspect of the present invention is a power management system comprising a plurality of power management devices as described above, connected via wiring, and a plurality of devices that function as either power loads, generators, or storage batteries and are connected to the plurality of power management devices.

[0020] According to the present invention, it is possible to realize a power management device and a power management system that can stably maintain the balance between power supply and demand.

[0021] Fig. 2 is a diagram illustrating an example of the configuration of a power management system according to an embodiment of the present invention. Fig. 3 is a block diagram illustrating a schematic configuration of the power management device shown in Fig. 1. Fig. 4 is a schematic diagram for explaining the operation of a port unit. Fig. 5 is a schematic diagram for explaining the operation of a port unit. Fig. 6 is a schematic diagram for explaining the operation of a port unit. Fig. 7 is a table illustrating example supply and demand information and power information. Fig. 8 is a diagram illustrating a modified example of a power management system.

[0022] Hereinafter, a power management apparatus and a power management system according to embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. In addition, in the description of each drawing, the same parts are designated by the same reference numerals.

[0023] FIG. 1 is a diagram illustrating an example of the configuration of a power management system according to an embodiment of the present invention. As shown in FIG. 1, the power management system 1 according to this embodiment includes multiple power management devices 10, 10a, 10b, 10c, 10d, etc. connected via wiring W, and multiple devices functioning as power loads, generators, or storage batteries. FIG. 1 illustrates generators 11a and 11d, storage batteries 12a and 12d, and loads 13a, 13b, and 13c. Hereinafter, the power management devices 10, 10a, 10b, 10c, 10d, etc. may be collectively referred to as the power management device 10. Furthermore, the generators 11a and 11d may be collectively referred to as the generator 11, the storage batteries 12a and 12d may be collectively referred to as the storage battery 12, and the loads 13a, 13b, and 13c may be collectively referred to as the load 13. The generator 10 is, for example, a solar power generation system, a wind power generation system, an ocean thermal energy conversion system, a wave power generation system, etc. The capacitor 12 may be a general capacitor or an electric vehicle.

[0024] In detail, a power generator 11a, a battery 12a, and a load 13a are connected to a power management device 10a used by user A. A load 13b is connected to a power management device 10b used by user B. A load 13c is connected to a power management device 10c used by user C. A power generator 11d and a battery 12d are connected to a power management device 10d used by user D. Furthermore, the power management devices 10a, 10b, and 10c are connected to each other, and the power management devices 10b and 10d are connected to each other.

[0025] In this way, the number of generators 11, storage batteries 12, loads 13, and other power management devices 10 that can be connected to one power management device 10 is not limited as long as it is equal to or less than the number of power input / output ports (described later) provided in each power management device 10. In other words, in the power management system 1, by connecting the power management devices 10 to each other via wiring W, any type of power transmission network can be formed.

[0026] The power management device 10 is a device that relays the transmission of power between the generator 11, the battery 12, and the load 13. As will be described later, each power management device 10 has a wired or wireless communication function, and can transmit information generated by itself to other power management devices 10 or terminals 20 via wiring W or a communication network N.

[0027] The communication network N may be, for example, the Internet, a LAN, a telecommunications line, or a combination thereof, and may be either wired or wireless. The terminal 20 may be, for example, a computer (PC), a notebook PC, a tablet terminal, a smartphone, etc. A server device for settling electricity usage charges between users may also be connected to the communication network N.

[0028] 2 is a block diagram showing a schematic configuration of the power management apparatus 10. As shown in FIG. 2, the power management apparatus 10 has a port unit 110, a communication unit 120, and a controller 130.

[0029] The port unit 110 includes three or more power input / output ports P1, P2, ..., P3, P4, and P5, a switch unit 111, and a power measurement unit 112. Each of the power input / output ports P1, P2, ..., P3, P4, and P5 is configured to be connectable to the generator 11, the battery 12, the load 13, and other power management devices 10 via wiring.

[0030] The switch unit 111 is configured to switchably connect two of three or more power input / output ports P1, P2, ..., P3, P4, P5 under the control of the controller 130, and transmit power between the two power input / output ports that are connected to each other.

[0031] The power measurement unit 112 is configured to measure the direction and amount of power transmitted between two connected power input / output ports at predetermined unit time intervals. The predetermined unit time is not particularly limited and can be set as appropriate, for example, every 30 seconds, every minute, every 5 minutes, every 30 minutes, or every hour.

[0032] 3A to 3C are schematic diagrams for explaining the operation of the port unit 110, showing the port unit 110 in user A's power management device 10a as an example. Hereinafter, the power input / output port will also be referred to simply as a port. As shown in FIGS. 3A to 3C, via wiring W, port P1 of power management device 10a is connected to user B's power management device 10b, and port P2 is connected to user C's power management device 10c. Furthermore, port P3 is connected to generator 11a, port P4 is connected to battery 12a, and port P5 is connected to load 13a.

[0033] 3A, when port P1 and port P3 are connected in switch unit 111, power is supplied from generator 11a to load 13b via power management device 10b. At this time, power measurement unit 112 measures the amount and direction of power flowing from port P3 to port P1.

[0034] 3B, when port P2 and port P4 are connected in switch unit 111, power is supplied from battery 12a to load 13c via power management device 10c. At this time, power measurement unit 112 measures the amount and direction of power flowing from port P4 to port P2.

[0035] 3C, when port P3 and port P5 are connected in switch unit 111, power is supplied from generator 11a to load 13a. At this time, power measurement unit 112 measures the amount and direction of power flowing from port P3 to port P5.

[0036] The communication unit 120 is a communication interface that transmits and receives information via power line communication (PLC) with another power management device 10 connected via wiring W. Alternatively, the communication unit 120 may connect the power management device 10 to a communication network N using Bluetooth (registered trademark), Wi-Fi (Wireless Fidelity), or various other communication technologies, and transmit and receive information with devices (other power management devices 10 and terminals 20) connected to the communication network N. Of course, the communication unit 120 may also communicate with other devices by combining PLC with other communication technologies.

[0037] The communication unit 120 is configured to transmit and receive at least device identification information (described later) assigned to each of the power management apparatus 10 and other connected power management apparatuses 10 .

[0038] The controller 130 is configured by, for example, a microcomputer, and includes a storage unit 140 and a processing unit 150 .

[0039] The storage unit 140 is a storage medium configured by a semiconductor memory such as a ROM or a RAM, and includes a program storage unit 141, an identification information storage unit 142, and a power information storage unit 143. The program storage unit 141 stores programs to be executed by the processing unit 150 and various parameters used during the execution of the programs.

[0040] The identification information storage unit 142 stores device identification information (hereinafter also referred to as device ID) assigned to each individual power management apparatus 10, and user identification information (hereinafter also referred to as user ID) assigned to each user who uses the power management apparatus 10. In principle, device IDs cannot be rewritten, but user IDs can be rewritten.

[0041] The power information storage unit 143 stores the power information generated by the power information generation unit 153, which will be described later.

[0042] The processing unit 150 is configured using, for example, a CPU (Central Processing Unit), and by reading programs stored in the program storage unit 141, it comprehensively controls each unit of the power management device 10 and executes various processes. Specifically, the processing unit 150 manages the supply and demand of power by transmitting and receiving information generated in the power management device 10 to and from other power management devices 10 and terminals 20, and executes various calculation processes for managing information used in settling power usage fees. Functional units realized by the processing unit 150 include a supply and demand information generation unit 151, a selection unit 152, a power information generation unit 153, and an identification information determination unit 154.

[0043] The supply and demand information generator 151 generates power supply and demand information for devices connected to the power management device 10, and transmits the supply and demand information at predetermined unit times between the power management device 10 and other power management devices 10 connected to the power management device 10. The supply and demand information includes the amount of power consumption required by the power management device 10 and the power shortage rate, or the amount of power that can be supplied and the power surplus rate, and price information presented for the purchase or sale of power. The supply and demand information may also include a device ID assigned to the power management device 10.

[0044] For example, the supply and demand information generated by user A's power management device 10a may include the amount of power that can be supplied by generator 11a and the power surplus rate, the amount of power consumed by load 13a and the power shortage rate, or the amount of power that can be supplied by battery 12a and the surplus rate or the amount of power required for charging and the shortage rate, etc.

[0045] Here, the supply and demand information for the generator 11a may be generated based on the rated output of the generator 11a as well as the power generation output at that time. For example, if the generator 11a is a solar power generation system, the power that can be supplied increases on sunny days and decreases on rainy days. Furthermore, the supply and demand information for the battery 12a may be generated based on the charge rate of the battery 12a. For example, when the charge rate is equal to or greater than a threshold, supply and demand information including the amount of power that can be supplied and the surplus rate may be generated, and when the charge rate is less than the threshold, supply and demand information including the required power and the shortage rate may be generated.

[0046] Furthermore, the supply and demand information generated by the power management device 10b used by user B may include the amount of power consumption required by the load 13b and the power shortage rate. In other words, the supply and demand information generation unit 151 generates supply and demand information according to the devices (generator 11, battery 12, load 13) connected to the power management device 10 and their operating states (power on / off, charging rate, etc.).

[0047] The price information included in the supply and demand information is information that represents the purchase price offered when receiving power supply from another power management device 10 (or a device connected to it), or information that represents the sales price offered when supplying power to another power management device 10 (or a device connected to it). The price information may be the amount itself, a multiple of a predetermined reference price, or the number of points.

[0048] The supply and demand information generation unit 151 may adjust the price information presented according to the amount of power consumption required by the equipment connected to the power management device 10 and the power shortage rate, or the amount of power that can be supplied and the power surplus rate.

[0049] Furthermore, when a load 13 is connected to the power management device 10 and the power shortage rate does not change for a predetermined period, the supply and demand information generation unit 151 may change the price information to raise the power purchase price. Conversely, when a generator 11 is connected to the power management device 10 and the power surplus rate does not change for a predetermined period, the supply and demand information generation unit 151 may change the price information to lower the power sales price.

[0050] Furthermore, the supply and demand information generating unit 151 may add the user ID stored in the identification information storage unit 142 to the supply and demand information and transmit it.

[0051] In principle, the time interval at which the supply and demand information generating unit 151 generates the supply and demand information and transmits it to another power management device 10 may be synchronized with the unit time at which the power measuring unit 112 measures power.

[0052] Supply and demand information may be transmitted and received between other power management devices 10 connected to the power management device 10 via wiring W using power line communication (PLC), or may be transmitted and received between other power management devices 10 via a communication network N.

[0053] The selector 152 is configured to determine, for each predetermined unit time, two ports to be connected to each other from among the three or more ports P1, P2, ... based on the received supply and demand information when the power management device 10 receives supply and demand information from another power management device 10. The selector 152 may be configured to operate in synchronization with the reception of supply and demand information by the supply and demand information generator 151.

[0054] In detail, the selector 152 can select one of two ports P1, P2, . . . to be connected to each other based on price information included in the supply and demand information received from another power management apparatus 10.

[0055] As an example, when user A's generator 11a is operating and user A's power management device 10a receives supply and demand information requesting power (i.e., including the required power and shortage rate) from both user B's power management device 10a and user C's power management device 10c, the power management device 10a compares the price information contained in the supply and demand information, connects the port connected to the power management device 10b, 10c with the higher purchase price represented by the price information, and transmits power from generator 11a.

[0056] As another example, when user B's load 13b is operating and user B's power management device 10b receives supply and demand information (i.e., including the supplied power and surplus rate) indicating that power will be supplied from both user A's power management device 10a and user D's power management device 10d, power management device 10b compares the price information contained in the supply and demand information, connects the port connected to the power management device 10a, 10d with the lower selling price represented by the price information, and transmits power to load 13b.

[0057] Furthermore, when a load 13 is connected to the power management device 10, the selector 152 may select, as one of two ports to be connected, the port P1, P2, ... to which the other power management device 10 with the highest surplus power rate is connected, based on supply and demand information received from another power management device 10. For example, when the power management device 10b of user B receives supply and demand information from both the power management device 10a of user A and the power management device 10d of user D, the power management device 10b connects the port to which the power management device 10a, 10d with the higher surplus power rate included in the supply and demand information is connected to the port to which the load 13b is connected, and transmits power to the load 13b.

[0058] Furthermore, when a power generator 11 is connected to the power management device 10, the selector 152 may select, as one of the two ports to be connected, the port P1, P2, ... to which the other power management device 10 with the highest power shortage rate is connected, based on supply and demand information received from another power management device 10. For example, when the power management device 10a of user A receives supply and demand information from both the power management device 10b of user B and the power management device 10c of user C, the power management device 10a connects the port to which the power management device 10b, 10c with the higher power shortage rate included in the supply and demand information is connected to the port to which the generator 11 is connected, and can transmit power from the generator 11.

[0059] Furthermore, when a battery 12 is connected to the power management device 10, and the battery 12 is in a charging mode, the selector 152 may select, as one of the two ports to be connected to the other power management device 10, the port P1, P2, ... to which the other power management device 10 with the highest surplus power rate is connected, based on supply and demand information received from the other power management device 10. On the other hand, when the battery 12 is in a discharging mode, the selector 152 may select, as one of the two ports P1, P2, ... to which the other power management device 10 with the highest shortage power rate is connected, based on supply and demand information received from the other power management transmission 10.

[0060] The parameters for adjusting price information according to the power surplus rate or shortage rate may be set by each user operating the power management device 10 via the terminal 20 .

[0061] The power information generation unit 153 is configured to generate power information including the direction and amount of power measured by the power measurement unit 112, price information included in supply and demand information transmitted to or received from another power management device 10 connected to one of the two interconnected ports, and the device ID of the other power management device 10, and record the information in the power information storage unit 143. The power information stored in the power information storage unit 143 is linked to the device ID assigned to the power management device 10, and is configured to be transmitted to the communication network N by the communication unit 120.

[0062] When a user ID is included in the supply and demand information received from another power management device 10, the identification information determination unit 154 determines whether this user ID is the same as the user ID stored in its own identification information storage unit 142.

[0063] Next, the operation of each power management device 10 in the power management system 1 will be described in detail. Fig. 4 is a table illustrating supply and demand information and power information, and shows an example of supply and demand information and power information generated by the power management device 10b used by user B. As shown in Fig. 1, a load 13b is connected to the power management device 10b, and therefore, when using the load 13b, it is necessary to receive a supply of power through the wiring W. In Fig. 4, the supply and demand information and power information are generated every minute. Also, in Fig. 4, the price information indicates a multiplier relative to a base price.

[0064] When connected to each other via the wiring W, each power management device 10 transmits and receives a device ID to and from the other power management device 10. This allows each power management device 10 to identify the source or destination of supply and demand information, and the power management device 10 that is the destination or source of power transmission.

[0065] When user B turns on the power switch of load 13b, power management device 10b generates supply and demand information for receiving power supply to load 13b and transmits it to power management devices 10a and 10d connected via wiring W. As shown in Fig. 4, the supply and demand information at the beginning (time 10:11:00) when the switch is turned on indicates that the required power is 20 W, the shortage rate is 100%, and the price information is 1.0.

[0066] User A's power management device 10a, user C's power management device 10c, and user D's power management device 10d receive the supply and demand information transmitted from user B's power management device 10b. Then, the power management device 10 that is able to supply power generates supply and demand information including the amount of power that can be supplied, the surplus power rate, and price information, and transmits this information to power information management device 10b. Here, it is assumed that supply and demand information is transmitted from user A's power management device 10a to user B's power management device 10b. Note that the price information included in the supply and demand information transmitted from power management device 10a may be the same as or different from the price information included in the supply and demand information transmitted from power management device 10b.

[0067] User A's power management device 10a transmits supply and demand information to power management device 10b and connects the port connected to generator 11a with the port connected to power management device 10b. Upon receiving the supply and demand information from power management device 10a, power management device 10b connects the port connected to power management device 10a with the port connected to load 13b. This starts power supply to load 13b (from time 10:12:00). After power supply starts, the power shortage in load 13b is resolved, and the supply and demand information generated by power management device 10b shows a shortage rate of 0%.

[0068] If the price information included in the supply and demand information received by power management device 10b from power management device 10a differs from the price information presented by power management device 10b, power management device 10b may determine whether to connect the port. The range (parameter) of price information for determining whether to connect the port can be set in advance in power management device 10b via terminal 20.

[0069] The power information generation unit 153 of the power management device 10b generates power information including the amount and transmission direction of power measured by the power measurement unit 112. This power information includes price information (1.0 at time 10:12:00) in the supply and demand information sent by the power management device 10b to the power management device 10a, and the device ID of the power management device 10a of user A.

[0070] When user B increases the power of load 13b to 30 W (time 10:19:00), load 13b will experience a power shortage if the power supply from power management device 10a remains at 20 W. In response, power management device 10b generates supply and demand information including information that the required power is 30 W and the shortage rate is 33%, and transmits this information to power management devices 10a, 10c, and 10d connected via wiring W.

[0071] When the amount of power transmitted from any of the power management devices 10a, 10c, and 10d is not increased and the shortage rate remains unchanged for a predetermined period of time, the power management device 10b changes the price information to raise the purchase price of power and transmits supply and demand information (time 10:24:00). In response, when one of the power management devices 10a, 10c, and 10d (e.g., power management device 10a) transmits supply and demand information with an increased supply of power, the power management device 10b connects ports based on this supply and demand information. This increases the transmitted power (see 10:25:00 in the power information), and the shortage rate in the supply and demand information becomes 0%. The price information in the power information is also changed accordingly.

[0072] When user B switches off load 13b (at 10:30:00), the required power in the supply and demand information becomes 0 W and the shortage rate becomes 0%. When load 13b is switched off, power management device 10b may transmit supply and demand information indicating a required power of 0 W and a shortage rate of 0%, or may stop transmitting the supply and demand information. Power management device 10b also disconnects the port. This also stops the transmission of power from power management device 10a to power management device 10b.

[0073] The power information generated by the power management device 10b is linked to the user ID of user B and transmitted to the communication network N. The power information is stored using a so-called blockchain mechanism, in which the power information is distributed and held among multiple terminals 20 connected to the communication network N, and as necessary, the power charges (or points) may be settled between users using the terminals 20. Alternatively, the power information may be stored in a settlement server device, and the settlement between users may be carried out on this server device.

[0074] As described above, according to this embodiment, supply and demand information is transmitted and received between the power management devices 10 connected via the wiring W, and the power supply destination or power source is determined based on the supply and demand information. Therefore, by performing this operation at predetermined time intervals, the supply and demand balance of the entire system naturally approaches a balanced state. Therefore, it is possible to stably maintain the power supply and demand balance in the power management system 1.

[0075] Furthermore, according to this embodiment, it is possible to settle the charges for the electricity supplied or consumed by each device by transmitting the electricity information to the terminal 20 connected to the communication network N. Furthermore, according to this embodiment, the electricity supply destination or electricity supplier is determined based on the price information included in the supply and demand information, so electricity charges are also stabilized overall.

[0076] Furthermore, according to this embodiment, the price information presented in the supply and demand information fluctuates depending on the state of supply and demand for electricity, which provides incentives such as reducing electricity consumption when prices are high, using electricity when prices are low, storing electricity when prices are low and discharging it when prices are high, making it possible to optimize the state of supply and demand for electricity across the entire system.

[0077] In the above example, power management device 10a supplies power in accordance with the supply and demand information transmitted by power management device 10b. However, if both power management devices 10a and 10d are able to supply power to power management device 10b, power management device 10b may determine (switch ports in port unit 110) to receive power from the device with the higher power surplus rate or the lowest quoted price based on price information, based on the supply and demand information transmitted from power management devices 10a and 10d. Such port switching may be performed at predetermined time intervals.

[0078] Furthermore, in the above example, the case where power management device 10b receives power supply has been described, but for example, when power management device 10a supplies power, the power supply destination can be determined in a similar manner by transmitting and receiving supply and demand information. That is, when power management device 10a receives supply and demand information indicating a power shortage from both power management devices 10b and 10c, it may determine to supply power to the device with a higher power shortage rate or the device with a higher quoted price based on price information.

[0079] Fig. 5 is a diagram showing a modified example of a power management system. The power management system 2 shown in Fig. 5 differs from the power management system shown in Fig. 1 in that power management devices 10a(1), 10a(2), and 10a(3) are connected to the end of user A's power management device 10a, and power management devices 10d(1) and 10d(2) are connected to the end of user D's power management device 10d. In other words, user A's generator 11a, battery 12a, and load 13a are connected to the power management device 10a via power management devices 10a(1), 10a(2), and 10a(3), respectively. User D's generator 11d and battery 12d are connected to the power management device 10d via power management devices 10d(1) and 10d(2), respectively.

[0080] In this way, by connecting the generator 11a, the battery 12a, and the load 13a via the power management devices 10a(1), 10a(2), and 10a(3), it is possible to automatically manage the generation and consumption of power at user A. For example, if the power management device 10a receives supply and demand information generated by the power management device 10a(1) when the generator 11a is operating and supply and demand information generated by the power management device 10a(3) when the load 13a is operating, the power management device 10a can determine (connect ports) so that the power generated by the generator 11a is consumed by the load 13a. Furthermore, based on the supply and demand information generated in the power management device 10a (2), the power management device 10a can determine (connect a port) to supply the power generated in the generator 11a to the battery 12a when the battery 12a is in charging mode (when the charging rate is less than a predetermined value), and to supply the power generated in the generator 11a to another user's equipment when the battery 12a is fully charged (when the charging rate is equal to or greater than a predetermined value).

[0081] Here, the power management devices 10a, 10a(1), 10a(2), and 10a(3) are assigned the user ID of the same user A. Therefore, the supply and demand information generation unit 151 of each power management device 10 may link its own user ID to the generated supply and demand information and transmit it to the other power management devices 10, and the identification information determination unit 154 may determine whether the user ID linked to the supply and demand information received from the other power management devices 10 is the same as its own user ID. Then, when the power management device 10 receives supply and demand information from multiple other power management devices 10, it may prioritize the supply and demand information linked to the same user ID as its own.

[0082] For example, if user A's power management device 10a receives supply and demand information simultaneously from both user A's power management device 10a(3) and user B's power management device 10b, the power generated by the generator 11a may be preferentially transmitted to the power management device 10a(3) of the same user.

[0083] In the above embodiment and modified example, two ports are connected in the port unit 111. However, depending on the system configuration, three or more ports may be connected to each other. In this case, for example, it is possible to supply power from one generator to multiple loads, supply power from multiple generators to one load, or supply power from one generator to a load while charging a battery with surplus power.

[0084] The present invention is not limited to the above-described embodiments and modifications, and can be embodied in various other forms without departing from the spirit of the present invention. For example, some components may be removed from all of the components shown in the embodiments and modifications, or the components shown in the above-described embodiments and modifications may be appropriately combined.

[0085] 1, 2... Power management system, 10, 10a, 10a(1), 10a(2), 10a(3), 10b, 10c, 10d, 10d(1), 10d(2)... Power management device, 11, 11a, 11d... Generator, 12, 12a, 12d... Storage battery, 13, 13a, 13b, 13c... Load, 20... Terminal, 110... Port unit, 111... Switch unit, 112... Power measurement unit, 120... communication unit, 130... controller, 140... storage unit, 141... program storage unit, 142... identification information storage unit, 143... power information storage unit, 150... processing unit, 151... supply and demand information generation unit, 152... selection unit, 153... power information generation unit, 154... identification information determination unit, P1, P2, ..., P3, P4, P5... power input / output ports (ports)

Claims

1. In a power management system, a power management device relays the transmission of power between a plurality of devices functioning as either a power load, a generator, or a power storage device, comprising: three or more power input / output ports configured to be connectable via wiring between the devices functioning as either a power load, a generator, or a power storage device and another power management device; a switch unit configured to switchably connect two of the three or more power input / output ports and transmit power between the two power input / output ports connected to each other; a memory unit configured to store device identification information individually assigned to the power management device; a communication unit configured to transmit at least the device identification information to and from the other power management device connected to the power management device; and a supply and demand information generation unit configured to generate supply and demand information for the devices connected to the power management device, the supply and demand information including the amount of required power consumption and a power shortage rate, or the amount of power that can be supplied and a power surplus rate, and price information presented for the purchase or sale of power, and to cause the other power management device connected to the power management device to transmit the supply and demand information at predetermined unit times; a selection unit configured to determine two power input / output ports to be connected to each other among the three or more power input / output ports for each specified unit time based on the supply and demand information received from another power management device.

2. A power management device as described in claim 1, further comprising: a power measurement unit configured to measure the direction and amount of power transmitted between two power input / output ports connected to each other at each specified unit time; and a power information generation unit configured to generate power information including the direction and amount of power measured by the power measurement unit, price information included in the supply and demand information transmitted or received between another power management device connected to one of the two power input / output ports connected to each other, and device identification information of the other power management device, wherein the memory unit further stores user identification information assigned to each user of the power management device, and the communication unit is configured to link the power information generated by the power information generation unit to the user identification information assigned to the power management device and transmit it to a communication network.

3. A power management device as described in claim 1 or 2, wherein when an apparatus functioning as a load is connected to the power management device, the selection unit selects, based on the supply and demand information received from another power management transmission, a power input / output port to which another power management device having the highest surplus power rate is connected as one of the two power input / output ports to be connected to each other.

4. A power management device as described in any one of claims 1 to 3, wherein when an appliance functioning as a generator is connected to the power management device, the selection unit selects, based on the supply and demand information received from the other power management devices, a power input / output port to which another power management device having the highest power shortage rate is connected as one of the two power input / output ports to be connected to each other.

5. A power management device according to any one of claims 1 to 4, wherein when a device functioning as a power storage device is connected to the power management device, when the device is in a power storage mode, the selection unit selects, based on the supply and demand information received from the other power management devices, a power input / output port to which the other power management device having the highest power surplus rate is connected, as one of the two power input / output ports to be connected to each other, and when the device is in a discharging mode, the selection unit selects, based on the supply and demand information received from the other power management devices, a power input / output port to which the other power management device having the highest power shortage rate is connected, as one of the two power input / output ports to be connected to each other.

6. A power management device as described in any one of claims 1 to 5, wherein when the selection unit receives the supply and demand information from another power management device, it selects one of the two power input / output ports to be connected to each other based on price information contained in the supply and demand information.

7. The power management device according to claim 6, wherein the supply and demand information generating unit adjusts the price information according to the amount of required power consumption and the power shortage rate, or the amount of power that can be supplied and the power surplus rate.

8. The power management device of claim 7, wherein the supply and demand information generation unit modifies the price information so as to raise the purchase price of electricity when a power shortage rate does not change for a specified period when a device functioning as a load is connected to the power management device, and modifies the price information so as to lower the selling price of electricity when a power surplus rate does not change for a specified period when a device functioning as a generator is connected to the power management device.

9. A power management device according to any one of claims 1 to 8, wherein the supply and demand information is transmitted and received between other power management devices via power line communication.

10. A power management device according to any one of claims 1 to 8, wherein the supply and demand information is transmitted and received between other power management devices via a communications network.

11. A power management system comprising: a plurality of power management devices according to any one of claims 1 to 8, the plurality of power management devices being connected via wiring; and a plurality of devices functioning as either power loads, generators, or power storage devices and connected to the plurality of power management devices.