Power management system, power management method, and program

Abstract

A power management system according to the present invention, in which charges per unit that are different from each other are respectively set for first purchased power that is supplied to a first electric device and second purchased power that is supplied to a second electric device, comprises: a first acquisition unit (for example, acquisition unit (71)) that acquires, from a first measurement device to which a distributed power supply and the first electric device are electrically connected, a first power value obtained by measuring power in the reverse power flow from the distributed power supply to an electric power system; a second acquisition unit (for example, acquisition unit (71)) that acquires, from a power meter which is electrically connected to the second electric device, a second power value obtained by measuring power in a forward power flow from the electric power system; and a calculation unit (72) that, on the basis of smaller one of the first power value and the second power value, calculates at least one of the amount of purchased power from the electric power system and the amount of power sold to the electric power system.

Description

Power management system, power management method and program

[0001] The present invention relates to a power management system, a power management method, and a program.

[0002] Conventionally, a method has been known in which multiple power meters are connected in a parent-child configuration to perform differential metering, thereby measuring power consumption by separating normal power loads from power loads to which dynamic pricing is applied (see Non-Patent Document 1).

[0003] Ministry of Economy, Trade and Industry, Agency for Natural Resources and Energy website [searched August 21, 2023], Internet <URL:https: / / www.enecho.meti.go.jp / category / electricity_and_gas / electric / measure / faq / 017.html>

[0004] However, the technology of Non-Patent Document 1 has a problem that when a facility such as a house has a distributed power source (private power generation facility) such as a solar battery, the amount of generated power consumed by the facility is also measured as the amount of purchased power. In addition, it is sometimes desirable to accurately calculate the amount of power sold.

[0005] Therefore, the present invention provides a power management system, a power management method, and a program that can accurately calculate at least one of the amount of purchased power and the amount of power sold when a distributed power source is present within a facility.

[0006] A power management system according to one aspect of the present disclosure is a power management system that manages the power of a first electrical device and a second electrical device, and different unit prices are set for first purchased power supplied to the first electrical device and second purchased power supplied to the second electrical device. The power management system includes: a first acquisition unit that acquires a first power value measured by a first meter electrically connecting the distributed power source and the first electrical device, the first power value measuring the power flowing backward from the distributed power source to the power grid; a second acquisition unit that acquires a second power value measured by a second meter electrically connected to the second electrical device, the second power value measuring the power flowing forward from the power grid; and a calculation unit that calculates at least one of the amount of power purchased from the power grid and the amount of power sold to the power grid based on the smaller of the first power value and the second power value.

[0007] A power management method according to one aspect of the present disclosure is a power management method executed by a power management system that manages the power of a first electrical device and a second electrical device, wherein different unit prices are set for first purchased power supplied to the first electrical device and second purchased power supplied to the second electrical device, and the power management method acquires a first power value that measures the power flowing backward from the distributed power source to a power grid from a first meter that is electrically connected to the distributed power source and the first electrical device, acquires a second power value that measures the power flowing forward from the power grid from a second meter that is electrically connected to the second electrical device, and calculates at least one of the amount of power purchased from the power grid and the amount of power sold to the power grid based on the smaller of the first power value and the second power value.

[0008] A program according to one aspect of the present disclosure is a program for causing a computer to execute the above-described power management method.

[0009] According to one aspect of the present disclosure, it is possible to realize a power management system or the like that can accurately calculate at least one of the amount of purchased power and the amount of power sold when a distributed power source is present within a facility.

[0010] FIG. 1 is a diagram illustrating a configuration of a power management system according to an embodiment. FIG. 2 is a block diagram illustrating a functional configuration of a management device according to an embodiment. FIG. 3 is a flowchart illustrating the operation of the management device according to an embodiment. FIG. 4 is a diagram illustrating a first application example of a power management system according to an embodiment. FIG. 5 is a diagram illustrating a second application example of a power management system according to an embodiment. FIG. 6 is a diagram illustrating a method for calculating interchange power in the second application example of a power management system according to an embodiment. FIG. 7 is a diagram illustrating a third application example of a power management system according to an embodiment. FIG. 8 is a diagram illustrating a fourth application example of a power management system according to an embodiment. FIG. 9 is a diagram illustrating a fifth application example of a power management system according to an embodiment. FIG. 10 is a diagram illustrating a sixth application example of a power management system according to an embodiment. FIG. 11 is a diagram illustrating a configuration of a power management system according to a modified example of an embodiment. FIG. 12 is a diagram illustrating a first application example of a power management system according to a modified example of an embodiment. FIG. 13 is a diagram illustrating a second application example of a power management system according to a modified example of an embodiment.

[0011] (How the present invention was arrived at) Before describing the present invention, how the present invention was arrived at will be described.

[0012] One pricing system for electricity usage in homes and other facilities is called dynamic pricing (DP), in which the unit price (power unit price) changes depending on the time of day. DP is a system that flexibly changes prices according to supply and demand. In particular, DP pricing plans that link the DP power unit price (DP unit price) to the spot price in the retail electricity market have been attracting attention in recent years.

[0013] However, increasing or decreasing the electricity demand associated with daily life in response to changes in the DP unit price (for example, by saving electricity when prices rise) imposes a burden on users. Therefore, it may be desirable to set DP only for power loads that are not directly linked to the electricity demand associated with daily life, such as the power consumption of electric water heaters and the power consumption of charging electric vehicles, and to use the conventional electricity rate system for other electricity consumption. Taking an electric water heater as an example, it is sufficient to heat the water before it is used, but since the timing of heating does not affect the user, it is possible to reduce electricity bills by automatically heating the water when the DP price is low. Furthermore, a power load that is directly linked to electricity demand refers to a power load that consumes electricity due to the user's operation of an electrical appliance (for example, turning on the air conditioner).

[0014] In this case, it is necessary to measure the power consumption separately for the normal power load and the power load to which DP is applied, and a method is proposed as disclosed in Non-Patent Document 1.

[0015] As explained in the "Problem to be Solved by the Invention" section, the method of Non-Patent Document 1 has the problem that, if a facility has a distributed power source, the self-consumption portion of the generated power is also measured as purchased power. For example, when a solar power generation system (e.g., a solar cell 10 and a power conversion system 20 shown in FIG. 1, which are an example of a distributed power source) supplies power to a power load that uses DP (i.e., self-consumption), the technology of Non-Patent Document 1 measures the DP purchased power and the self-consumption power together. Therefore, even if a facility has a distributed power source, it may be desirable to measure the purchased power and the self-consumption separately. It may also be desirable to accurately calculate the sold power, which can fluctuate depending on the purchased power.

[0016] Therefore, the inventors of the present application conducted extensive research into power management systems that can accurately calculate at least one of the amount of purchased electricity and the amount of electricity sold when there is a distributed power source within the facility, for example, systems that can separate purchased electricity from the amount consumed by the facility, and have devised the power management system described below.

[0017] Hereinafter, embodiments and the like will be specifically described with reference to the drawings.

[0018] The embodiments and the like described below are all comprehensive or specific examples. The numerical values, shapes, components, the arrangement and connection of the components, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0019] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0020] Furthermore, in this specification, terms indicating relationships between elements such as "same," as well as numerical values ​​and numerical ranges, are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about several percent (or about 10%).

[0021] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between components of the same type.

[0022] Furthermore, the "connection" of each component means an electrical connection, and includes not only a case where two components are directly connected, but also a case where two components are indirectly connected with another component inserted between them.

[0023] (Embodiment) Hereinafter, a power management system according to the present embodiment will be described with reference to Figs.

[0024] [1. Configuration of Power Management System] First, the configuration of a power management system 1 according to this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a diagram showing the configuration of a power management system 1 according to this embodiment.

[0025] As shown in FIG. 1, the power management system 1 is a system for managing the power of a first electric device (for example, a home appliance 51) and a second electric device (for example, a charger 52).

[0026] The power management system 1 includes a solar cell 10 ("PV" in FIG. 1 ), a power conversion system 20 ("PCS" in FIG. 1 ), a storage battery 30 ("SB" in FIG. 1 ), power meters 41 and 42 ("M1" and "M2" in FIG. 1 ), home appliances 51 that are power demands within the home 100, a charger 52, current sensors 61 and 62 ("CT1" and "CT2" in FIG. 1 ), a management device 70, and a power meter 200 ("M0" in FIG. 1 ), all of which are arranged in a home 100, and a power grid 300. The home appliances 51 and the charger 52 are examples of electrical appliances that generate power demand. Note that the power management system 1 is only required to include at least the management device 70.

[0027] The house 100 is an example of a facility. The facility may be a residential facility or a non-residential facility. Examples of residential facilities are a detached house and an apartment building. Each of the multiple dwelling units in an apartment building may be considered a "facility," or the entire apartment building may be considered a "facility." Examples of non-residential facilities include a store, an office building, a school, a welfare facility, a commercial complex, a hospital, and a factory.

[0028] It is assumed that the consumer of the house 100 has a contract with the retail electricity supplier to pay an electricity fee according to the power measured by the power meter 41 under a conventional electricity rate system (fixed power unit price) and to pay an electricity fee according to the power measured by the power meter 42 under a dynamic pricing electricity rate system (DP unit price). It is also assumed that the consumer has a contract to have the retail electricity supplier purchase the selling power measured by the power meter 41 from the consumer.

[0029] The solar cell 10 is an electric power device that converts light energy into electrical energy (power) by utilizing the photovoltaic effect. The solar cell 10 is an example of a distributed power source.

[0030] The power conversion system 20 is also called a power conditioner, and converts DC power generated by the solar cell 10 into AC power. The power conversion system 20 may also acquire measured values ​​from the current sensors 61 and 62 in order to cause the storage battery 30 to perform an environment-prioritizing operation described below.

[0031] The storage battery 30 is a device capable of charging and discharging, and is, for example, a home storage battery. The storage battery 30 can operate in environmentally prioritized operation. The environmentally prioritized operation means that when the measured current of the power meter 200 is positive (forward current) (when purchasing power), the storage battery 30 discharges to reduce this current (to reduce purchased power), and when the measured current is negative (reverse current) (when selling power reversely), the storage battery 30 charges to reduce this current (to reduce power sold reversely). The environmentally prioritized operation means that the storage battery 30 charges and discharges to bring the power measured by the power meter 200 closer to zero. The measured current of the power meter 200 can be obtained, for example, based on the measurement results of the current sensors 61 and 62.

[0032] The power meter 41 is a power sensor that measures the power (power value W1_b shown in FIG. 1 ) supplied to the home appliance 51. The power meter 41 measures, for example, the forward power supplied from the power grid 300 to the home appliance 51 (i.e., purchased under a conventional electricity rate system). When the power (PV power) generated by the solar cell 10 is not diverted (supplied) to the home appliance 51, the power meter 41 measures only the forward power (forward power = power value W1_b) supplied from the power grid 300 to the home appliance 51. Here, the forward power (hereinafter also referred to as purchased power) is power that is subject to billing for calculating electricity charges under a conventional electricity rate system.

[0033] Furthermore, a part or all of the PV power generated by the solar cell 10 is sold to the power grid 300 (electricity retailer) or the like via the power meter 41. For example, the power meter 41 also measures the sold power (power value W1_s shown in FIG. 1 ). The power meter 41 is electrically connected to each of the solar cell 10 and the home appliance 51. The power meter 41 may be a conventional (analog) power meter or a so-called smart meter. A smart meter is a power meter that measures power usage at shorter intervals (for example, every 30 minutes) than conventional meters and has a communication function. The power meter 41 is an example of a first measuring instrument.

[0034] The power meter 42 is a power sensor that measures the power supplied to the charger 52 (power value W2_b shown in FIG. 1 ). The power meter 42 measures, for example, the forward power supplied from the power grid 300 to the charger 52 (i.e., purchased under a dynamic pricing electricity rate system). When the PV power generated by the solar cell 10 is not diverted (supplied) to the charger 52, the power meter 42 measures only the forward power (forward power = power value W2_b) supplied from the power grid 300 to the charger 52. When the PV power generated by the solar cell 10 is diverted (supplied) to the charger 52, the power meter 42 measures the total power of the forward power supplied from the power grid 300 to the charger 52 and interchangeable power Y (forward power + interchangeable power Y = power value W2_b). Here, the forward power (hereinafter also referred to as purchased power) is the power that is charged for calculating the electricity rate under a dynamic pricing electricity rate system. It should be noted that the power meter 42 cannot measure the forward power and the interchange power Y separately.

[0035] The power meter 42 is electrically connected to the power meter 200 and the charger 52. For example, the power meter 42 is connected only to the charger 52. Connecting only to the charger 52 means being connected so as to be able to measure only the power supplied to the charger 52, and for example, means being connected to the charger 52 without going through another power meter. The power meter 42 may be a conventional power meter or a so-called smart meter. The power meter 42 is an example of a second measuring instrument.

[0036] The home appliance 51 is an electric appliance that consumes power and is installed in the house 100. The home appliance 51 is an appliance that generates power demand and is an example of a first electric appliance. The first electric appliance may be an electric load that is directly linked to the power demand associated with real life, and examples of the first electric appliance include home appliances 51 such as an air conditioner, a refrigerator, and a television, but may also include electric appliances other than the home appliance 51.

[0037] The first electrical appliance is subject to a conventional electricity rate system, i.e., a fixed electricity price without dynamic pricing. The fixed electricity price does not change depending on the electricity supply and demand situation, and is set in advance, for example, at the time of signing the contract.

[0038] The charger 52 is a charging facility (or a charging / discharging facility) that charges a storage battery mounted on a vehicle that can run on electricity, such as an EV (Electric Vehicle) or a PHEV (Plug-in Hybrid Electric Vehicle), and is an example of a second electrical device. The second electrical device is an electrical load that is not directly linked to the electrical demand associated with real life, and may be, for example, an electric water heater. A DP unit price is applied to the second electrical device.

[0039] In this way, different power unit prices (fee unit prices) are set for the purchased power supplied to the first electrical device (first purchased power) and the purchased power supplied to the second electrical device (second purchased power). The number of first electrical devices and the number of second electrical devices included in the power management system 1 are not particularly limited, as long as they are one or more. A power unit price other than the DP unit price may be applied as the power unit price for the second electrical device. The power unit price for the second electrical device may be any power unit price different from the power unit price for the first electrical device, and may be, for example, a different fixed power unit price different from the fixed power unit price for the first electrical device.

[0040] The current sensors 61 and 62 measure the current flowing at predetermined positions. Each of the current sensors 61 and 62 includes, for example, a current transformer and an ammeter connected to the current transformer. The current sensors 61 and 62 are disposed on the power distribution line between the distribution board of the house 100 and the power meter 200.

[0041] The current sensor 61 is provided between the power meters 41 and 200 on a dedicated wiring of the house 100, and measures the current (reverse current) flowing through the wiring. In other words, the current sensor 61 measures the current output from the house 100 to the power grid 300.

[0042] Current sensor 62 is provided between power meters 42 and 200 on a dedicated wiring in house 100, and measures the current (forward current) flowing through the wiring. In other words, current sensor 62 measures the current (forward current) flowing to charger 52.

[0043] Note that the power management system 1 may include one current sensor (for example, current sensor 63 shown in FIG. 5 , which will be described later) at the power receiving point instead of the current sensors 61 and 62. The one current sensor measures the current flowing at the power receiving point. In other words, the one current sensor measures the current flowing from the power receiving point to the house 100 (downstream) and the current flowing from the house 100 to the power receiving point (upstream). By including such a current sensor in the power management system 1, the house 100 can meet the conditions for using the FIT system (Feed-In Tariff: Feed-in Tariff system).

[0044] The current value measured by the current sensors 61 and 62 can be substituted for the current value measured by at least one of the power meters 41, 42, and 200. For example, the current value measured by the current sensor 61 can be substituted for the current value of reverse power measured by the power meter 41 or 200. Also, the current value measured by the current sensor 62 can be substituted for the current value of forward power measured by the power meter 42. Therefore, for example, when the current value measured by at least one of the power meters 41, 42, and 200 is output to the management device 70, at least one of the current sensors 61 and 62 (for example, both) does not need to be provided.

[0045] The management device 70 manages the power of the first electric device and the second electric device. For example, the management device 70 performs various processes for transferring a part or all of the power generated by the solar cell 10 to the charger 52. The management device 70 may be provided within the house 100 or may be provided remotely from the house 100. The management device 70 may be provided in a control terminal for controlling the home appliances 51 provided within the house 100, or may be realized by a server device connected to each meter and each sensor so as to be able to communicate with them.

[0046] FIG. 2 is a block diagram showing the functional configuration of the management device 70 according to this embodiment.

[0047] 2, the management device 70 includes an acquisition unit 71, a calculation unit 72, and an output unit 73. Each component of the management device 70 is realized, for example, by a microcomputer, a processor, or the like (hardware) constituting the management device 70 executing a computer program (software) stored in a storage unit (not shown).

[0048] The acquisition unit 71 acquires power values ​​measured from various measuring instruments. The acquisition unit 71 acquires, from the power meter 41, a power value W1_s (an example of a first power value) that measures the power flowing backward from the solar cell 10 to the power grid 300. The acquisition unit 71 functions as a first acquisition unit. The acquisition unit 71 also acquires, from the power meter 42, a power value W2_b (an example of a second power value) that measures the power flowing forward from the power grid 300. The acquisition unit 71 also functions as a second acquisition unit. The acquisition unit 71 also acquires, from the power meter 41, a power value W1_b that measures the power flowing forward from the power grid 300 to the home appliance 51. The power values ​​W1_s, W1_b, and W2_b are expressed in units of, for example, "W (watt)."

[0049] The acquisition unit 71 may be configured to include a communication module (communication circuit) for communicating with the power meters 41 and 42. The acquisition unit 71 may communicate via wired communication or wireless communication. Furthermore, there are no particular limitations on the communication standard used for communication. Furthermore, the acquisition unit 71 is not limited to directly communicating with the power meters 41 and 42, and may acquire the power values ​​measured by the power meters 41 and 42 via another device. Furthermore, the acquisition unit 71 may be connected to an input device such as a button, a touch panel, or a sound collection device (e.g., a microphone), and may be able to acquire each power value without going through a communication network.

[0050] The calculation unit 72 calculates the amount of power purchased from the power grid 300 and the amount of power sold to the power grid 300 in the house 100 based on the acquired power values ​​W1_s and W2_b. Specifically, the calculation unit 72 calculates the amount of power purchased and the amount of power sold based on the smaller of the power values ​​W1_s and W2_b. The calculation unit 72 calculates, for example, the smaller power value as interchange power Y (first interchange power) to be lent from the solar cell 10 to the charger 52, calculates the amount of power purchased and the amount of power sold by subtracting the interchange power Y from the power values ​​W1_s and W2_b, and calculates the amount of power purchased and the amount of power sold by integrating the calculated amount of power purchased and the amount of power sold.

[0051] When the power value W1_s is smaller than the power values ​​W1_s and W2_b, for example, the entire power value W1_s is set as interchange power Y (= power value W1_s) to the charger 52, and the shortfall is purchased from the power grid 300. In this case, the sold power is zero. Also, when the power value W2_b is smaller than the power values ​​W1_s and W2_b, for example, the power value W2_b minus the power value W1_s is set as interchange power Y (= power value W2_b) to the charger 52, and the surplus is sold to the power grid 300 or lent to the home appliance 51. In this case, the purchased power for the charger 52 is zero.

[0052] The purchased electricity and sold electricity can be expressed as the following formula:

[0053] Purchased power for charger 52=W2_b−Y [W] (Formula 1) Sold power=W1_s−Y [W] (Formula 2) Interchanged power Y=Min(W1_s, W2_b) [W] (Formula 3) Purchased power for home appliance 51=W1_b [W] (Formula 4)

[0054] The power calculated by Equation 1 is the power to which the DP unit price is applied, and the power calculated by Equation 4 is the power to which a fixed power unit price is applied. The purchased power for home appliance 51 means the power that is subject to billing at the conventional fixed power unit price. The purchased power for charger 52 means the power that is subject to billing at the DP unit price.

[0055] Furthermore, in the power management system 1 , the power supply path is controlled so that the interchange power Y calculated by the calculation unit 72 is actually supplied to the charger 52 .

[0056] The interchanged power Y corresponds to the amount of PV power of the solar cell 10 that is self-consumed by the charger 52. The calculation unit 72 calculates the power purchased by the charger 52 using the above-mentioned formulas 1 and 3, so that the power measured by the power meter 42 can be separated into the power purchased from the power grid 300 and the power self-consumed by the charger 52.

[0057] The calculation unit 72 may calculate at least one of the amount of purchased power and the amount of sold power.

[0058] The output unit 73 outputs the amount of purchased energy and the amount of sold energy calculated by the calculation unit 72 to an external device (e.g., a higher-level system). The output unit 73 outputs the amount of purchased energy and the amount of sold energy to, for example, a server device managed by an electricity retailer. The output unit 73 outputs the amount of purchased energy calculated by integrating the purchased energy calculated using Equation 1 over a predetermined period as the amount of energy to be charged at the DP unit price, and outputs the amount of purchased energy calculated by integrating the purchased energy calculated using Equation 4 over a predetermined period as the amount of energy to be charged at a conventional fixed energy unit price. Thus, in the example of FIG. 1 , the output unit 73 outputs, as the amount of purchased energy to be charged at the DP unit price, not the amount of energy actually calculated by integrating the energy measured by the energy meter 42 but the amount of energy calculated by subtracting the interchange power Y from the energy measured by the energy meter 42.

[0059] The output unit 73 outputs the amount of purchased power and the amount of sold power, for example, by wireless communication, but may also output the amount of purchased power and the amount of sold power by wired communication. Furthermore, the output unit 73 may output the amount of purchased power and the amount of sold power to a terminal device of a consumer.

[0060] Referring again to FIG. 1 , the power meter 200 is a power sensor connected between the power meters 41 and 42 and the power grid 300, and measures at least one of a third power value (power value W_b shown in FIG. 5 , which will be described later) of forward power flow from the power grid 300 and a fourth power value (power value W_s shown in FIG. 5 , which will be described later) of reverse power flow from the solar cell 10 to the power grid 300. The power meter 200 measures, for example, power supplied from one of the retail electricity supplier and the power receiving point to the other (i.e., power supplied (purchased) from the power grid 300 to the house 100, and power sold from the house 100 to the power grid 300). In this way, the power meter 200 functions as at least one of a power receiving power meter that measures power supplied from the power grid 300 and a power selling power meter that measures power sold from the house 100 to the retail electricity supplier at a predetermined unit price using the FIT system. The power meter 200 is an example of a third metering instrument.

[0061] The power receiving point where the power meter 200 is installed may be a responsibility separation point between the area belonging to the house 100 and the area belonging to the power grid 300, or may be a location where an inlet switchboard (low voltage) or a power receiving equipment (high voltage) is located.

[0062] The electricity retailer is a business that buys and sells electricity based on the measurement value of the power meter 200. The electricity retailer sells electricity to ordinary households, buildings, factories, etc. The measurement value of the power meter 200 is transmitted to the electricity retailer.

[0063] The power grid 300 is a grid operated by an electricity retailer and includes a grid power source.

[0064] 3 is a flowchart showing the operation (power management method) of the management device 70 according to this embodiment. Steps S11 and S12 are executed before power interchange is performed.

[0065] 3 , the acquisition unit 71 of the management device 70 acquires, from the power meter 41, a first power value that measures the power flowing backward from the distributed power source to the power grid 300 (S11). In step S11, the acquisition unit 71 acquires a power value W1_s.

[0066] Next, the acquisition unit 71 acquires a second power value that measures the forward power flow from the power meter 42 (S12). In step S12, the acquisition unit 71 acquires a power value W2_b.

[0067] The timing and order of obtaining the first power value and the second power value are not particularly limited, and the first power value and the second power value may be obtained simultaneously.

[0068] Next, the calculation unit 72 calculates the amount of power to be purchased from the power grid 300 and the amount of power to be sold to the power grid 300 based on the smaller power value of the first power value and the second power value (S13). The calculation unit 72 calculates the amount of power to be purchased and the amount of power to be sold using the above-mentioned Equations 1 to 3.

[0069] Next, the output unit 73 outputs the amount of purchased power and the amount of sold power calculated by the calculation unit 72 to an external device (S14). This makes it possible to calculate, for example, the purchase price and the sale price based on the accurate amount of purchased power and the amount of sold power.

[0070] [3. Application Examples of Power Management Systems] Application examples of the power management system 1 according to the present embodiment will be described below with reference to FIGS. 4 to 10. First, a first application example will be described with reference to FIG. 4. FIG. 4 is a diagram showing the first application example of the power management system 1 according to the present embodiment. In FIG. 4, an example will be described in which the power meters 441 and 442 are each smart meters. The power meter 441 corresponds to the power meter 41 shown in FIG. 1 and is an example of a first meter. The power meter 442 corresponds to the power meter 42 shown in FIG. 1 and is an example of a second meter. A current sensor 61 is arranged downstream of the power meter 441, and a current sensor 62 is arranged downstream of the power meter 442. The power meters 441 and 442 are built into the housing 400, for example.

[0071] 4 and subsequent figures, the management device 70, the house 100, and the like are omitted for the sake of convenience.

[0072] 4 , a power meter 441, which is a smart meter, is disposed between the power system 300 and the home appliance 51, and a power meter 442, which is a smart meter, is disposed between the power system 300 and the charger 52. Each of the power meters 441 and 442 is disposed at a responsibility separation point between an area belonging to the house 100 and an area belonging to the power system 300, and in this application example, power interchange is performed upstream of the power meters 441 and 442.

[0073] In this case, the calculation unit 72 calculates the smaller of the first power value (power value W1_s) which is the reverse flow power obtained from the power meter 441, and the second power value (power value W2_b) which is the forward flow power obtained from the power meter 442, as the interchanged power Y to be interchanged from the distributed power source to the second electrical device. Then, the calculation unit 72 calculates the amount of purchased power and the amount of sold power by subtracting the interchanged power Y from the first power value and the second power value. Note that the interchange of power may be performed via a power transmission and distribution network maintained and operated by a general power transmission and distribution specialist.

[0074] Next, a second application example will be described with reference to FIGS. 5 and 6 . FIG. 5 is a diagram showing a second application example of the power management system 1 according to the present embodiment. In FIG. 5 , an example will be described in which the power meters 41 and 42 are not smart meters but conventional power meters, and the power meter 200 is disposed at a responsibility decomposition point. The power meter 200 may be a smart meter or a conventional power meter. Furthermore, the power meters 41 and 42 may be, under certain conditions, measuring instruments (specified measuring instruments) that are not subject to inspection based on the Measurement Act. Furthermore, the acquisition unit 71 is communicably connected to the power meter 200 and acquires measurement values ​​from the power meter 200.

[0075] 5 , the power meters 41 and 42 are disposed on a distribution board 80a to which a home appliance 51 and a charger 52 are connected, and the power meter 200 is connected between the distribution board 80a and the power grid 300. In this application example, the power meter 200 measures at least a third power value (i.e., a power value W_b that is the purchased power (forward current power) that the house 100 purchases from the power grid 300). The power meters 41 and 42 may also be capable of measuring power every few milliseconds. A current sensor 63 is disposed between the power meter 200 and the distribution board 80a.

[0076] In such a case, the calculation unit 72 calculates each power using the following equations 5 and 6.

[0077] Purchased power for home appliance 51 (first purchased power)=W_b-(W2_b-Y) [W] (Formula 5) Purchased power for charger 52 (second purchased power)=W2_b-Y [W] (Formula 6)

[0078] The formula for calculating the interchange power Y is the same as formula 3, and therefore will not be repeated.

[0079] Furthermore, (W2_b-Y) in Equation 6 means a second power value, which is the power flowing forward from the power grid 300 to the charger 52 (power purchased from the power grid 300). The power interchange of the interchangeable power Y here can be performed downstream of the power meter 200 located at the responsibility decomposition point. For example, this can be performed via wiring within the house 100. The interchangeable power Y is in-house interchangeable power that can be interchanged within the house 100. In other words, the power management system 1 according to this application example allows power interchange without using a power transmission and distribution network maintained and operated by a general power transmission and distribution specialist.

[0080] The calculation unit 72 calculates the first purchased power amount by subtracting the second power value from the third power value (power value W_b) as shown in Equation 5.

[0081] Furthermore, the calculation unit 72 may calculate the load power (power consumption) of the entire house 100 using the following formula 7, and may calculate the load power (power consumption) of devices other than the charger 52 in the house 100 using the following formula 8. Devices other than the charger 52 refer to all devices installed in the house 100 to which a fixed electricity unit price applies (i.e., all devices to which the DP price does not apply).

[0082] Power consumption of the entire house 100=W_b+PV power−W_s (Equation 7) Power consumption of all devices in the house 100 other than the charger 52=W_b+PV power−W_s−W2_b (Equation 8)

[0083] Furthermore, the calculation unit 72 may switch the calculation method of the interchange power Y depending on the unit price of electricity for the second purchased electricity. A case where the calculation method of the interchange power Y is switched will be described with reference to FIG. 6 . FIG. 6 is a diagram for explaining a calculation method of the interchange power Y in a second application example of the electricity management system 1 according to the present embodiment. (a) of FIG. 6 is a diagram for explaining a calculation method of the interchange power Y when the dynamic pricing price rises, and (b) of FIG. 6 is a diagram for explaining a calculation method of the interchange power Y when the dynamic pricing price falls. Note that in FIG. 6 , the connection relationship within the distribution board 80a is changed from that in FIG. 5 . For example, the home appliance 51 is connected so that it can receive power from the power grid 300 without going through the power meter 41.

[0084] A period when the dynamic pricing price is rising may be, for example, when the DP unit price is equal to or greater than the fixed electricity unit price (an example of a predetermined unit price), and a period when the dynamic pricing price is falling may be, for example, when the DP unit price is less than the fixed electricity unit price (an example of a predetermined unit price). Note that the predetermined unit price is not limited to the fixed electricity unit price, but may be another unit price that is set in advance. Furthermore, the predetermined unit prices that determine whether prices are rising or falling may be the same unit price or may be different unit prices. The predetermined unit price is stored, for example, in the memory unit of the management device 70. Furthermore, the acquisition unit 71 may acquire the DP unit price from a server device that manages the DP unit prices, etc.

[0085] The calculation unit 72 determines whether the DP unit price is equal to or greater than a predetermined unit price, and changes the calculation method in step S13 shown in FIG. 3 depending on the determination result.

[0086] 6(a), when the DP unit price rises, interchange power Y1 is preferentially transferred to the charger 52. In this case, the PV power generated by the solar cell 10 is not charged to the storage battery 30, and is managed so that it is transferred as much as possible to the charger 52 to which the DP unit price applies. The calculation unit 72 calculates each power using the following equations 9 to 11.

[0087] Interchanged power Y1=Min(PV power, W2_b) [W] (Equation 9) Purchased power for charger 52 (second purchased power)=W2_b-Y1 [W] (Equation 10) Purchased power for home appliance 51 (first purchased power)=W_b-(W2_b-Y1) [W] (Equation 11)

[0088] The interchanged power Y1 is the PV power that is interchanged with the charger 52, and is an example of first interchanged power.

[0089] In this way, when the power unit price (DP unit price) for the second purchased power is equal to or higher than a predetermined unit price, the calculation unit 72 calculates the smaller power value of the PV power and the power value W2_b as the interchange power Y1.

[0090] 6(b), when the DP unit price falls, interchanged power Y2 (an example of second interchanged power) is preferentially transferred to home appliance 51. In this case, PV power generated by solar cell 10 is managed so that it is transferred as much as possible to home appliance 51 to which a fixed power unit price is applied. The calculation unit 72 calculates each interchanged power using the following equations 12 and 13.

[0091] Interchangeable power Y2 = Min (PV power, W1_b) [W] (Formula 12) Interchangeable power Y1 = PV power - W_s - Y2 [W] (Formula 13)

[0092] The purchased power for the charger 52 (second purchased power) and the purchased power for the home appliance 51 (first purchased power) can be calculated by substituting the interchange power Y1 of Equation 13 into Equation 10 and Equation 11. The power value W1_b can be obtained from the measurement values ​​of the power meters 41, 42, and 200.

[0093] When the DP unit price drops, power may not be lent to the charger 52. In other words, the lent power Y1 may be zero. For example, (PV power - Y2) shown in Equation 13 may be the same value as the power value W_s.

[0094] In this way, when the power unit price (DP unit price) for the second purchased power is less than the predetermined unit price, the calculation unit 72 calculates as the interchanged power Y1 a power value (power value calculated by Equation 13) that is lower than the interchanged power Y1 calculated by Equation 9. When the power unit price for the second purchased power is less than the predetermined unit price, the calculation unit 72 may set the interchanged power Y1 to 0, or may calculate the interchanged power Y1 based on the interchanged power Y2 interchanged from the solar cell 10 to the home appliance 51.

[0095] Next, a third application example will be described with reference to Fig. 7. Fig. 7 is a diagram showing a third application example of the power management system 1 according to the present embodiment. Fig. 7 describes an example in which a specific metering panel 90 is provided.

[0096] As shown in Fig. 7 , the power management system 1 further includes a specified meter panel 90 that incorporates power meters 41 and 42, which are specified meters. The specified meter panel 90 is connected between the power meter 200 and a distribution panel 80 to which the home appliances 51 are connected. It can also be said that the power meter 200 is connected between the power system 300 and the specified meter panel 90. The specified meter panel 90 is also connected to the power conversion system 20 (i.e., the solar cell 10) and the charger 52. Note that the power meters 41 and 42 are not provided on the distribution panel 80.

[0097] The power purchased from the power meter 200 (power purchased from the power grid 300) can be supplied to the home appliance 51 via the distribution board 80, and to the charger 52 via the power meter 42. In addition, the PV power can be supplied to the home appliance 51 and the charger 52 via the power meter 41, and can also be sold.

[0098] For example, the specific metering panel 90 is a box provided as dedicated hardware different from the distribution panel 80, and is configured to be able to switch between selling the PV power of the solar cell 10 via the power meter 200, supplying it to the charger 52 via the power meter 42, or supplying it to the home appliance 51 via the distribution panel 80. The specific metering panel 90 is a two-input, two-output specific metering panel.

[0099] In this way, the specific metering panel 90 (i.e., hardware) determines where the PV power of the solar cell 10 is supplied, so the reliability of the measurement values ​​measured by the power meters 41 and 42 can be improved.

[0100] When the specific metering panel 90 is provided, the calculation method for the interchange power Y1 and Y2 may be switched depending on the level of the DP unit price. In this case, the calculation method is dynamically switched by the management device 70.

[0101] Next, a fourth application example will be described with reference to Fig. 8. Fig. 8 is a diagram showing a fourth application example of the power management system 1 according to the present embodiment. Fig. 8 describes an example in which a switch unit 95 is provided in addition to a specific metering panel 90a.

[0102] 8 , the power management system 1 includes a specified meter panel 90a that incorporates power meters 41 and 42, which are specified meters, as well as a switch unit 95 that switches between connecting the power conversion system 20 (i.e., the solar cell 10) to the home appliance 51 via the power meter 41 and distribution panel 80 or connecting the power meter 42 and charger 52. The switch unit 95 is a physical switch that has one movable contact and two fixed contacts (fixed contacts A and B), but may also be, for example, a touch switch. Fixed contact A is connected to the home appliance 51 via the power meter 41 and distribution panel 80, and fixed contact B is connected to the power meter 42 and charger 52.

[0103] The switch unit 95 is controlled to switch the connection destination depending on whether the DP unit price is equal to or greater than a predetermined price. When the DP unit price is equal to or greater than a first predetermined price, the switch unit 95 connects the movable contact to the fixed contact B, and when the DP unit price is less than a second predetermined price that is equal to or less than the first predetermined price (for example, when the DP unit price is less than the first predetermined price), the switch unit 95 connects the movable contact to the fixed contact A. This makes it possible to reduce the amount of power purchased from the power grid 300.

[0104] In this case, the switch unit 95 is dynamically switched based on the DP unit price, but the calculation method for the interchange power Y is fixed (for example, Equation 6). When the movable contact and fixed contact A are connected, the power meter 41 measures the surplus power obtained by subtracting the power supplied to the home appliance 51 from the PV power as the power value W1_s. When the movable contact and fixed contact B are connected, the power meter 42 measures the surplus power obtained by subtracting the power supplied to the charger 52 from the PV power as the power value W1_s.

[0105] Furthermore, the interchange power Y can be calculated using the power value W1_s of the reverse flow power measured by the power meter 41 and the power value W2_b of the forward flow power measured by the power meter 42 according to Equation 3.

[0106] The control of the switch unit 95 and the determination of whether the DP unit price is equal to or greater than a predetermined unit price may be performed by the management device 70 or by another device.

[0107] Next, a fifth application example will be described with reference to Fig. 9 . Fig. 9 is a diagram showing the fifth application example of the power management system 1 according to the present embodiment. Fig. 9 describes an example in which power is exchanged upstream of power meters 200, 201, and 202, which are smart meters. Fig. 9 also illustrates an air conditioner 51a, which is an example of a home appliance 51, and an electric vehicle V10 connected to a charger 52.

[0108] 9 , the power management system 1 includes power meters 200, 201, and 202. The power meters 200, 201, and 202 are smart meters. Furthermore, one or two of the power meters 200, 201, and 202 may be located in a location remote from the residence 100. For example, the power meter 200 may be located in the residence 100, and the power meters 201 and 202 may be located in different locations remote from the residence 100. The power meter 201 is an example of a first meter, and the power meter 202 is an example of a second meter.

[0109] When power is interchanged in such a configuration, the power is interchanged upstream of the power meters 200, 201, and 202. The power may be interchanged, for example, via a power transmission and distribution network maintained and operated by a general power transmission and distribution company.

[0110] The calculation unit 72 calculates the interchange power when PV power is interchanged with at least one of the home appliance 51 and the charger 52. The management device 70 may also sell all of the PV power without interchange. The following describes a case where power is interchanged with the home appliance 51 and the charger 52. It is also assumed that the DP unit price is low. In this case, the calculation unit 72 determines that power should be preferentially interchanged with the home appliance 51.

[0111] The calculation unit 72 first calculates the interchange power Y1 to the home appliance 51, and if the PV power is greater than W1_b, further calculates the interchange power Y2 to the charger 52. The calculation unit 72 calculates the interchange powers Y1 and Y2 based on the following Equations 14 and 15.

[0112] Interchangeable power Y1 = Min (PV power, W1_b) [W] (Formula 14) Interchangeable power Y2 = Min (PV power - Y1, W2_b) [W] (Formula 15)

[0113] Furthermore, the calculation unit 72 calculates the sold power and purchased power (charged power) in this case based on the following formulas 16 to 18.

[0114] Sold power=PV power−Y1−Y2 [W] (Formula 16) Purchased power for home appliance 51=W1_b−Y1 [W] (Formula 17) Purchased power for charger 52=W2_b−Y2 [W] (Formula 18)

[0115] This makes it possible to calculate the amount of purchased power when interchange is performed upstream of the power meters 41 and 42, for example, when self-consignment is performed between points in a three-supply point contract.

[0116] Next, a sixth application example will be described with reference to Fig. 10. Fig. 10 is a diagram showing a sixth application example of the power management system 1 according to the present embodiment. Fig. 10 describes an example in which the DP unit price differs depending on the device in the house 100.

[0117] As shown in FIG. 10 , the power management system 1 includes electrical appliances, such as a home appliance 51, a charger 52, and an electric water heater 53. The home appliance 51 is a device to which a fixed electricity unit price applies. The charger 52 and the electric water heater 53 are devices to which a DP unit price applies, but the DP unit prices are different. The DP unit price for the charger 52 is defined as a first DP unit price, and the DP unit price for the electric water heater 53 is defined as a second DP unit price. The first DP unit price and the second DP unit price fluctuate depending on the time of day, so there are times when the first DP unit price is high and times when the second DP unit price is high. In this application example, the destination to which PV power is supplied (the priority order for supply) dynamically changes depending on the level of the first DP unit price and the second DP unit price. The following mainly describes the case where the first DP unit price is higher than the second DP unit price (i.e., the charger 52 is given priority over the electric water heater 53).

[0118] Furthermore, the power management system 1 includes a power meter 43 ("M3" in FIG. 10) in addition to the power meters 41 and 42. The power meter 43 measures the forward flow of power (purchased power) from the power grid 300 to the electric water heater 53. The acquisition unit 71 of the management device 70 is configured to be able to acquire the power value W3_b measured by the power meter 43.

[0119] In this case, the calculation unit 72 first calculates the interchange power Y1 for the charger 52 that has the highest priority for interchange. The calculation unit 72 calculates the interchange power Y1 using, for example, Equation 3. Next, when the power value W2_b is smaller than the power value W1_s, the calculation unit 72 further calculates the interchange power Y2 for the electric water heater 53 using the following Equation 19.

[0120] Interchangeable power Y2==Min((W1_s-Y1), W3_b)[W] (Formula 19)

[0121] When the second DP unit price is higher than the first DP unit price, the calculation unit 72 calculates the interchange powers Y2 and Y1 using the following formulas 20 and 21.

[0122] Interchangeable power Y2==Min(W1_s, W3_b)[W] (Formula 20) Interchangeable power Y1==Min((W1_s-Y2), W2_b)[W] (Formula 21)

[0123] This makes it possible to calculate the purchased power (power minus interchange power) for each device even if the house 100 has devices with different DP unit prices.

[0124] In addition, when the first DP unit price and the second DP unit price are the same unit price, PV power may be supplied preferentially to a preset device out of the charger 52 and the electric water heater 53 .

[0125] The interchange of power may be carried out using wiring within the house 100, or may be carried out via a power transmission and distribution network maintained and operated by a general power transmission and distribution specialist.

[0126] (Modification of the embodiment) The power management system 1 according to this modification will be described below with reference to Figures 11 to 13. Note that the following description will focus on differences from the embodiment, and descriptions of content that is the same as or similar to the embodiment will be omitted or simplified.

[0127] FIG. 11 is a diagram showing the configuration of a power management system 1 according to this modification. In this modification, a case will be described in which the solar cell 10 is installed in the home 100a by a PPA (Power Purchase Agreement) operator. The PPA operator sells the power (PV power) generated by the solar cell 10 to the consumer of the home 100a. Furthermore, if the storage battery 30 is installed in the home 100a by the PPA operator, when discharged power from the storage battery 30 is supplied to the home appliance 51, the PPA operator sells power to the consumer of the home 100a. Note that a retail electricity supplier may also carry out the PPA business.

[0128] As shown in FIG. 11, the power management system 1 includes a power meter 44 ("M4" shown in FIG. 11) in addition to the components of the power management system 1 shown in FIG.

[0129] The power meter 44 is connected between the power conversion system 20 and the home appliance 51, and measures a power value W3_s supplied from the PPA provider to the home appliance 51 and a power value W3_b of power purchased from a retail electricity supplier. It can also be said that the power meter 44 measures the power supplied from one of the solar cell 10 (an example of a distributed power source) installed by the PPA provider and the home appliance 51 (an example of a first electrical device) to the other. The power meter 44 may be a conventional power meter or a smart meter. The power meter 44 is an example of a fourth measuring instrument.

[0130] The acquisition unit 71 of the management device 70 also functions as a third acquisition unit that acquires the power values ​​W3_s and W3_b from the power meter 44 .

[0131] The calculation unit 72 calculates the amount of power purchased by the consumer in the house 100a using the following equations 22 to 25.

[0132] Power purchased from the retail electricity supplier for the home appliance 51=W1_b−W3_b [W] (Equation 22) Power purchased from the PPA supplier for the home appliance 51=W3_s [W] (Equation 23) Power purchased from the retail electricity supplier for the charger 52=W2_b−Y [W] (Equation 24) Power purchased from the PPA supplier for the charger 52=Y [W] (Equation 25)

[0133] Furthermore, the calculation unit 72 calculates the amount of electricity sold by the PPA company to the consumer, the amount of electricity purchased by the PPA company from the electricity retailer, and the amount of electricity sold by the PPA company to the electricity retailer using the following equations 26 to 29. Note that equation 29 is an equation for calculating the amount of electricity purchased by the PPA company from the electricity retailer for the home appliance 51.

[0134] Power sold by the PPA company to the home appliance 51=W3_s−W1_s [W] (Equation 26) Power sold by the PPA company to the charger 52=Y [W] (Equation 27) Power sold to the electricity retailer=W1_s−Y [W] (Equation 28) Power purchased from the electricity retailer=W3_b [W] (Equation 29)

[0135] Next, application examples of the power management system 1 according to this modification will be described. In the following, an example in which the power management system 1 according to this modification is applied to a first application example among the application examples of the embodiment will be shown in Fig. 12, and an example in which the power management system 1 according to this modification is applied to a second application example will be shown in Fig. 13. Figs. 12 and 13 are diagrams showing application examples of the power management system 1 according to this modification. Note that the power management system 1 according to this modification can be applied to any of the application examples of the embodiment.

[0136] As shown in FIG. 12, the power management system 1 according to this modification includes a power meter 44 in addition to the power management system 1 shown in FIG. 4 according to the embodiment.

[0137] The power meter 44 is connected between the power meter 441 and the distribution board 80 and the power conversion system 20 .

[0138] In this power management system 1 as well, the calculation unit 72 can calculate various types of power by using the above-mentioned formulas 22 to 29.

[0139] 13, the power management system 1 according to this modification has a configuration in which the home appliance 51 is connected via a branch circuit 81 in the power management system 1 shown in FIG. 5 of the embodiment. In this case, there is no need to provide the power meter 44.

[0140] In this case, the calculation unit 72 calculates the amount of power purchased by the consumer of the house 100a using the following formulas 30 and 31.

[0141] Power purchased from the retail electricity supplier for the home appliance 51=W_b−W1_b−W2_b [W] (Equation 30) Power purchased from the PPA supplier for the home appliance 51=W1_b−Y−W_s [W] (Equation 31)

[0142] The amount of power purchased from the retail electricity supplier for the charger 52 and the amount of power purchased from the PPA supplier for the charger 52 can be calculated using Equations 24 and 25, and therefore will not be described here.

[0143] In addition, the calculation unit 72 calculates the electricity sold by the PPA company to consumers, the electricity purchased by the PPA company from retail electricity companies, and the electricity sold by the PPA company to retail electricity companies using the following equations 32 to 34.

[0144] Power sold by PPA company to home appliance 51=W1_b−Y−W_s [W] (Equation 32) Power sold to retail electricity company=W_s [W] (Equation 33) Power purchased from retail electricity company=W1_b [W] (Equation 34)

[0145] The amount of electricity sold by the PPA company to the charger 52 can be calculated using Equation 27, and the description thereof will be omitted.

[0146] In such a power management system 1, the calculation unit 72 can also calculate various types of power by using the above-mentioned formulas 24, 25, 27, and 30 to 34.

[0147] (Effects, etc.) The invention derived from the disclosure of this specification and the effects, etc. obtained by the invention will be described below.

[0148] (Invention 1) An energy management system 1 that manages the power of a first electric device (e.g., a home appliance 51) and a second electric device (e.g., a charger 52), in which different unit prices are set for first purchased power supplied to the first electric device and second purchased power supplied to the second electric device, and the energy management system 1 receives a first power value (e.g., a power meter 41) that measures power flowing backward from the distributed power source to the power grid 300 from a first measuring device (e.g., a power meter 41) electrically connected to the distributed power source (e.g., a solar cell 10). a second acquisition unit (e.g., the acquisition unit 71) that acquires a second power value (e.g., a power value W2_b) that measures the forward power flow from the power grid 300 from a second measuring instrument (e.g., a power meter 42) electrically connected to the second electrical device; and a calculation unit 72 that calculates at least one of the amount of power purchased from the power grid 300 and the amount of power sold to the power grid 300 based on the smaller of the first power value and the second power value.

[0149] As a result, in the power management system 1, when the smaller power value, which is the power value based on the reverse power flow, is used to supply power to the second electric appliance and sell power to the electric power grid 300, the smaller power value is used, so it is possible to reduce the influence of the self-consumption by the second electric appliance on at least one of the measured amount of purchased power and the amount of sold power. Therefore, when a distributed power source is present within a facility (for example, within the home 100), the power management system 1 can accurately calculate at least one of the amount of purchased power and the amount of sold power.

[0150] (Invention 2) In the power management system 1 of Invention 1, the calculation unit 72 calculates the smaller power value as the first interchange power to be lent from the distributed power source to the second electrical device, and calculates at least one of the amount of purchased power and the amount of sold power by subtracting the first interchange power from the first power value and the second power value.

[0151] As a result, the first interchanged power is subtracted from the second power value, and the second power value can be separated into the first interchanged power, which is the amount of power self-consumption by the second electric device, and the amount of power purchased from the power grid 300. Therefore, it is possible to accurately calculate at least one of the amount of power purchased and the amount of power sold.

[0152] (Invention 3) The power management system 1 of Invention 2 is configured such that the calculation unit 72 switches the calculation method for the first interchange power depending on the power unit price for the second purchased power.

[0153] This makes it possible to reduce the purchase price from the power grid 300, thereby reducing the financial burden on consumers who use the power management system 1 for purchasing power.

[0154] (Invention 4) In the power management system 1 of Invention 3, the calculation unit 72 calculates the smaller power value as the first interchange power when the power unit price for the second purchased power is equal to or greater than a predetermined unit price, and calculates a power value lower than the smaller power value as the first interchange power when the power unit price for the second purchased power is less than the predetermined unit price.

[0155] As a result, when the unit price of electricity is high, the amount of first interchangeable power increases, and when the unit price of electricity is low, the amount of first interchangeable power decreases, thereby effectively reducing the financial burden on consumers who have the power management system 1 for purchasing electricity.

[0156] (Invention 5) In the power management system 1 of Invention 4, the calculation unit 72 sets the first interchanged power to 0 when the unit price of electricity for the second purchased power is less than a predetermined unit price, or calculates the first interchanged power based on the second interchanged power lent from the distributed power source to the first electrical equipment.

[0157] As a result, when the unit price of the second purchased power is less than the predetermined unit price, priority is given to the first electric appliance in providing power, so that the amount of power purchased for the first electric appliance can be reduced. Therefore, even when the unit price of the second purchased power is low, the financial burden on consumers for purchasing power can be reduced.

[0158] (Invention 6) The power management system 1 according to any one of Inventions 1 to 5, further comprising a first measuring instrument and a second measuring instrument, the first measuring instrument and the second measuring instrument being smart meters.

[0159] This makes it possible to accurately calculate the amount of purchased power and the amount of sold power when the first measuring instrument and the second measuring instrument are smart meters.

[0160] (Invention 7) The power management system 1 of any of Inventions 2 to 5 further includes a first meter and a second meter, and a third meter (e.g., a power meter 200) connected between the first meter and the second meter and the power system 300, and measuring at least one of a third power value flowing forward from the power system 300 and a fourth power value flowing backward from the distributed power source to the power system 300, wherein the first meter and the second meter are provided on a distribution board 80a to which the first electric device and the second electric device are connected, and the third meter is connected between the distribution board 80a and the power system 300.

[0161] This makes it possible to accurately calculate the amount of purchased power and the amount of sold power when the first meter and the second meter are provided on the distribution board 80a.

[0162] (Invention 8) The power management system 1 of Invention 7, wherein the third meter measures at least a third power value, and the calculation unit 72 calculates the first purchased power by subtracting the second power value from the third power value.

[0163] This allows the calculation unit 72 to easily calculate the first purchased power amount.

[0164] (Invention 9) A power management system 1 according to any of Inventions 1 to 8, further comprising a first meter and a second meter, a third meter connected between the first meter and the second meter and the power system 300 and measuring a third power value flowing forward from the power system 300, and a specific meter panel 90 connected between the third meter and a distribution board 80 to which the first electrical equipment is connected, the specific meter panel 90 to which a distributed power source and the second electrical equipment are connected, the first meter and the second meter being provided on the specific meter panel 90, and the third meter being connected between the specific meter panel 90 and the power system 300.

[0165] This makes it clear that power is only supplied to devices connected to the specific meter panel 90, thereby reducing the sense of uncertainty in calculating the amount of power.

[0166] (Invention 10) The power management system 1 of Invention 9 further comprises a switch unit 95 that switches between connecting the distributed power source to the first meter and the first electrical device or connecting the distributed power source to the second meter and the second electrical device.

[0167] This allows the connection to be switched by a physical switch, further reducing the opacity in calculating the amount of power consumed.

[0168] (Invention 11) In the power management system 1 of Invention 10, the switch unit 95 connects the distributed power source to the first meter and the first electrical device when the unit price of electricity for the second purchased power is equal to or greater than a predetermined unit price, and connects the distributed power source to the second meter and the second electrical device when the unit price of electricity for the second purchased power is less than the predetermined unit price.

[0169] As a result, the switch unit 95 can be used to reduce the financial burden on consumers who have the power management system 1 when purchasing power.

[0170] (Invention 12) The power management system 1 of any of Inventions 1 to 11, wherein the power unit price for the first purchased power is a preset fixed power unit price, and the power unit price for the second purchased power is a power unit price determined by dynamic pricing.

[0171] This makes it possible to accurately calculate the amount of purchased power and the amount of sold power when the different unit prices are a fixed power unit price and a power unit price based on dynamic pricing.

[0172] (Invention 13) The power management system 1 according to any one of Inventions 1 to 12, wherein the first electric device includes a home appliance 51, and the second electric device includes at least one of a charger 52 and an electric water heater 53.

[0173] This makes it possible to accurately calculate the amount of electricity purchased by the charger 52 and the electric water heater 53 in the power management system 1 that includes the home appliance 51 and at least one of the charger 52 and the electric water heater 53 .

[0174] (Invention 14) The power management system 1 according to any one of Inventions 1 to 13 further includes a third acquisition unit (e.g., acquisition unit 71) that acquires a measured fourth power value from a fourth measuring device (e.g., power meter 44) that measures the power supplied from one of the distributed power source and the first electrical device to the other, and the calculation unit 72 further calculates at least one of the amount of power purchased and the amount of power sold based on the fourth power value.

[0175] As a result, since the fourth power value is used, in a case where the PPA company has deployed distributed power sources, it is possible to accurately calculate at least one of the amount of purchased power and the amount of sold power.

[0176] (Invention 15) The power management system 1 according to any one of Inventions 1 to 14, wherein the calculation unit calculates both the amount of purchased power and the amount of sold power based on the smaller power value of the first power value and the second power value.

[0177] This allows the power management system 1 to accurately calculate both the amount of purchased power and the amount of sold power.

[0178] (Invention 16) A power management method is executed by a power management system 1 that manages the power of a first electric device (e.g., a home appliance 51) and a second electric device (e.g., a charger 52), in which different unit prices are set for first purchased power supplied to the first electric device and second purchased power supplied to the second electric device, and the power management method acquires a first power value that measures power flowing backward from the distributed power source to the power grid 300 from a first meter (e.g., a power meter 41) electrically connected to the distributed power source (e.g., a solar cell 10) and the first electric device (S11), acquires a second power value that measures power flowing forward from the power grid 300 from a second meter (e.g., a power meter 42) electrically connected to the second electric device (S12), and calculates at least one of the amount of power purchased from the power grid 300 and the amount of power sold to the power grid 300 based on the smaller of the first power value and the second power value (S13).

[0179] (Invention 17) A program for causing a computer to execute the power management method of invention 16.

[0180] This provides the same effects as those of the power management system 1 described above.

[0181] These general or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM, or as any combination of the system, method, integrated circuit, computer program, or recording medium. The program may be pre-stored in the recording medium, or may be supplied to the recording medium via a wide area communication network including the Internet.

[0182] (Other Embodiments) Although the power management system according to one or more aspects has been described above based on the embodiments, the present invention is not limited to these embodiments. As long as it does not deviate from the spirit of the present invention, various modifications conceivable by a person skilled in the art to the present embodiments and embodiments constructed by combining components of different embodiments may also be included in the present invention.

[0183] For example, in the above embodiments, a solar cell 10 (photovoltaic power generation device) is used as an example of a distributed power source, but this is not limited to this, and the distributed power source may be, for example, a wind power generation device, a hydroelectric power generation device, a geothermal power generation device, a biomass power generation device, or a combination of these.

[0184] In the above-described embodiments, an example has been described in which a conventional fee system is applied to a first electric appliance, which is an electric load that is directly linked to electric power demand associated with real life, and a dynamic pricing fee system is applied to a second electric appliance, which is an electric load that is not directly linked to electric power demand associated with real life. However, this is not limiting, and for example, a dynamic pricing fee system may be applied to the first electric appliance and a normal fee system may be applied to the second electric appliance. Furthermore, at least one of the electric appliances to which the conventional fee system is applied and the electric appliances to which the dynamic pricing fee system is applied may include a mixture of first electric appliances and second electric appliances.

[0185] In addition, in the above embodiments, an example has been described in which a dynamic pricing fee system is applied to the second electrical device, but this is not limited to this, and other fee systems in which the unit price of electricity varies depending on the situation may also be applied.

[0186] In the above embodiments, the contracted power that a home has with a retail electricity supplier may be high-voltage power (e.g., higher than 60 A, 50 kW or more and less than 2000 kW) or low-voltage power (e.g., 60 A or less and less than 50 kW). The first and second electrical appliances are commonly supplied with either low-voltage power or high-voltage power. That is, the first and second electrical appliances are each supplied with low-voltage power, or the first and second electrical appliances are each supplied with high-voltage power.

[0187] Furthermore, in the above-described embodiment and the like, an example has been described in which the management device 70 calculates both the amount of purchased power and the amount of power sold. However, for example, it may calculate only one of the amount of purchased power and the amount of power sold.

[0188] The order in which the steps in the flowchart are executed is merely an example for specifically explaining the present invention, and other orders may be used. Some of the steps may be executed simultaneously (in parallel) with other steps, or some of the steps may not be executed.

[0189] The division of functional blocks in the block diagram is an example, and multiple functional blocks may be realized as a single functional block, one functional block may be divided into multiple blocks, or some functions may be moved to another functional block.Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in time-sharing by a single piece of hardware or software.

[0190] Furthermore, the management device according to the above-described embodiments may be realized as a single device or may be realized by multiple devices. When the management device is realized by multiple devices, the components of the management device may be distributed among the multiple devices in any manner. When the management device is realized by multiple devices, the communication method between the multiple devices is not particularly limited, and may be wireless communication or wired communication. Furthermore, wireless communication and wired communication may be combined between the devices.

[0191] Furthermore, each component described in the above embodiments may be implemented as software or, typically, as an LSI, which is an integrated circuit. These components may be individually integrated into a single chip, or some or all of them may be integrated into a single chip. Here, the term "LSI" is used, but depending on the level of integration, it may also be referred to as an IC, system LSI, super LSI, or ultra LSI. Furthermore, the integrated circuit implementation method is not limited to LSI, and may be implemented using a dedicated circuit (a general-purpose circuit that executes a dedicated program) or a general-purpose processor. After LSI fabrication, a field programmable gate array (FPGA) that can be programmed or a reconfigurable processor that can reconfigure the connections or settings of circuit cells within the LSI may also be used. Furthermore, if an integrated circuit technology that replaces LSI emerges due to advances in semiconductor technology or a derivative technology, that technology may naturally be used to integrate the components.

[0192] A system LSI is an ultra-multifunctional LSI manufactured by integrating multiple processing units on a single chip. Specifically, it is a computer system that includes a microprocessor, ROM (Read Only Memory), RAM (Random Access Memory), etc. Computer programs are stored in the ROM. The system LSI achieves its functions when the microprocessor operates in accordance with the computer program.

[0193] Another aspect of the present invention may be a computer program that causes a computer to execute each of the characteristic steps included in the power management method shown in FIG.

[0194] Furthermore, for example, the program may be a program to be executed by a computer. Another aspect of the present invention may be a computer-readable non-transitory recording medium on which such a program is recorded. For example, such a program may be recorded on a recording medium and distributed or circulated. For example, the distributed program may be installed in a device having another processor, and the program may be executed by the processor, thereby causing the device to perform each of the above processes.

[0195] REFERENCE SIGNS LIST 1 Power management system 10 Solar cell (distributed power source) 41, 201, 441 Power meter (first meter) 42, 202, 442 Power meter (second meter) 44 Power meter (fourth meter) 51 Home appliance (first electrical appliance) 51a Air conditioner (first electrical appliance) 52 Charger (second electrical appliance) 53 Electric water heater (second electrical appliance) 71 Acquisition unit (first acquisition unit, second acquisition unit, third acquisition unit) 72 Calculation unit 80, 80a Distribution board 90, 90a Specific metering panel 95 Switch unit 200 Power meter (third meter) 300 Power system

Claims

1. An energy management system that manages the power of a first electrical device and a second electrical device, wherein different unit prices are set for a first purchased power supplied to the first electrical device and a second purchased power supplied to the second electrical device, and the energy management system comprises: a first acquisition unit that acquires a first power value measuring power flowing backward from the distributed power source to the power grid from a first meter electrically connected to the distributed power source and the first electrical device; a second acquisition unit that acquires a second power value measuring power flowing forward from the power grid from a second meter electrically connected to the second electrical device; and a calculation unit that calculates at least one of the amount of energy purchased from the power grid and the amount of energy sold to the power grid based on the smaller of the first power value and the second power value.

2. The power management system described in claim 1, wherein the calculation unit calculates the smaller power value as a first interchanged power to be lent from the distributed power source to the second electrical device, and calculates at least one of the purchased power amount and the sold power amount by subtracting the first interchanged power from the first power value and the second power value.

3. The power management system according to claim 2, wherein the calculation unit switches a calculation method for the first interchanged power depending on a unit price of power for the second purchased power.

4. The power management system described in claim 3, wherein the calculation unit calculates the smaller power value as the first interchangeable power when the power unit price for the second purchased power is equal to or greater than a predetermined unit price, and calculates a power value lower than the smaller power value as the first interchangeable power when the power unit price for the second purchased power is less than the predetermined unit price.

5. The power management system described in claim 4, wherein the calculation unit sets the first interchangeable power to 0 when the power unit price for the second purchased power is less than a predetermined unit price, or calculates the first interchangeable power based on the second interchangeable power lent from the distributed power source to the first electrical equipment.

6. The power management system according to any one of claims 1 to 5, further comprising the first measuring instrument and the second measuring instrument, wherein the first measuring instrument and the second measuring instrument are smart meters.

7. The power management system according to any one of claims 2 to 5, further comprising: the first meter and the second meter, and a third meter connected between the first meter and the second meter and the power grid, for measuring at least one of a third power value flowing forward from the power grid and a fourth power value flowing backward from the distributed power source to the power grid, wherein the first meter and the second meter are provided in a distribution board to which the first electrical device and the second electrical device are connected, and the third meter is connected between the distribution board and the power grid.

8. The power management system according to claim 7, wherein the third measuring device measures at least the third power value, and the calculation unit calculates the first purchased power by subtracting the second power value from the third power value.

9. A power management system as described in any one of claims 1 to 5, further comprising: a specific metering panel connected between the first metering instrument, the second metering instrument, and the power grid, for measuring a third power value flowing forward from the power grid; and a specific metering panel connected between the third metering instrument and a distribution board to which the first electrical equipment is connected, the specific metering panel to which the distributed power source and the second electrical equipment are connected; the first metering instrument and the second metering instrument are provided on the specific metering panel; and the third metering instrument is connected between the specific metering panel and the power grid.

10. The power management system according to claim 9, further comprising a switch unit that switches whether the distributed power source is connected to the first meter and the first electrical device, or to the second meter and the second electrical device.

11. The power management system described in claim 10, wherein the switch unit connects the distributed power source to the first meter and the first electrical device when the unit price of electricity for the second purchased power is equal to or greater than a predetermined unit price, and connects the distributed power source to the second meter and the second electrical device when the unit price of electricity for the second purchased power is less than the predetermined unit price.

12. An energy management system as described in any one of claims 1 to 5, wherein the unit price of electricity for the first purchased electricity is a preset fixed unit price of electricity, and the unit price of electricity for the second purchased electricity is a unit price of electricity determined by dynamic pricing.

13. The power management system according to any one of claims 1 to 5, wherein the first electrical device includes a home appliance, and the second electrical device includes at least one of a charger and an electric water heater.

14. An energy management system as described in any one of claims 1 to 5, further comprising a third acquisition unit that acquires a measured fourth power value from a fourth meter that measures the power supplied from one of the distributed power source and the first electrical device to the other, wherein the calculation unit further calculates at least one of the amount of purchased energy and the amount of sold energy based on the fourth power value.

15. The power management system according to any one of claims 1 to 5, wherein the calculation unit calculates both the amount of purchased power and the amount of sold power based on the smaller of the first power value and the second power value.

16. A power management method executed by a power management system that manages the power of a first electric device and a second electric device, wherein different unit prices are set for first purchased power supplied to the first electric device and second purchased power supplied to the second electric device, the power management method comprising: acquiring a first power value measuring power flowing backward from the distributed power source to the power grid from a first meter electrically connected to the distributed power source and the first electric device; acquiring a second power value measuring power flowing forward from the power grid from a second meter electrically connected to the second electric device; and calculating at least one of the amount of power purchased from the power grid and the amount of power sold to the power grid based on the smaller of the first power value and the second power value.

17. A program for causing a computer to execute the power management method according to claim 16.

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