Power management system, power conversion system

Abstract

To satisfy the principle of same time same amount of electricity with high quality.SOLUTION: A power conversion system (10) can control so that the tidal current values between a distributed power system (1) and a distribution panel (3) to which a load (4) is connected, and a transmission and distribution network (2) are at set values. When power is exchanged between the plurality of distributed power generation systems (1) via the transmission and distribution network (2), a notification unit of a power management system (50) notifies a power conversion system (10a) on the power transmission side of the tidal current value setting value on the power transmission side, and notifies a power conversion system (10b) on the power receiving side of the tidal current value setting value on the power receiving side so that the power released from a power distribution board (3a) on the power transmission side to the power transmission and distribution network (2) corresponds to the power that a power distribution board (3b) on the power receiving side draws from the power transmission and distribution network (2).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power management system and a power conversion system for managing power sharing between a plurality of distributed power systems.

Background Art

[0002] In Japan, the spread of solar power generation systems has been expanding against the backdrop of the Feed-in Tariff (FIT) system for renewable energy. With the end of the Feed-in Tariff system since November 2019 and the annual decline in the purchase price, P2P (Peer to Peer) transactions between individuals for electricity have attracted attention.

[0003] In order to maintain the stability of the power grid, the principle of simultaneous equal quantity is required. Since the power generated by solar cells changes every moment due to solar radiation fluctuations, it is difficult to satisfy the principle of simultaneous equal quantity.

[0004] As a method of sharing the amount of electricity for which a sale and purchase has been concluded in P2P transactions, control is conceivable in which the amount of electricity sold is discharged from the storage battery of the electricity consumer of the seller and the amount of electricity purchased is charged into the storage battery of the electricity consumer of the buyer (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] During the period when a seller (electricity consumer) is discharging electricity from their battery according to the agreed-upon amount, if there are significant changes in the load's self-consumption or the power generated by solar panels, the amount of electricity flowing back into the power grid can change significantly. Similarly, during the period when a buyer (electricity consumer) is charging their battery according to the agreed-upon amount, if there are significant changes in the load's self-consumption or the power generated by solar panels, the amount of electricity drawn from the power grid can change significantly.

[0007] This disclosure is made in light of these circumstances, and its purpose is to provide a power management system and a power conversion system that can satisfy the principle of simultaneous and equal supply in power exchange with high quality. [Means for solving the problem]

[0008] To solve the above problems, a power management system in one aspect of the present disclosure is a power management system for managing the exchange of power between a plurality of distributed power systems connected to the same power transmission and distribution network, wherein each distributed power system has a power storage unit and a power conversion system. The power conversion system is controllable so that the power flow value between the distribution board to which the distributed power system and loads are connected and the power transmission and distribution network is set to a set value, and the power management system includes a notification unit that notifies the power conversion system on the transmitting side of the set value of the power flow value on the transmitting side and notifies the power conversion system on the receiving side of the set value of the power flow value on the receiving side, so that the power discharged from the distribution board on the transmitting side to the power transmission and distribution network corresponds to the power drawn in by the distribution board on the receiving side to the power transmission and distribution network.

[0009] Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between devices, systems, methods, computer programs, etc., are also valid forms of this disclosure. [Effects of the Invention]

[0010] According to this disclosure, the principle of simultaneous and equal supply can be met with high quality in power exchange. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram illustrates the mechanism of power exchange between multiple distributed power systems. [Figure 2] This figure shows an example configuration of a power management system according to an embodiment. [Figure 3] This figure illustrates specific examples of the power conversion system on the selling side and the power conversion system on the buying side during the power exchange period according to the embodiment. [Figure 4] This is a flowchart illustrating the basic operation of the power management system according to the embodiment, specifically regarding power trading. [Figure 5] This is a timing chart illustrating an example of operation 1 during the power exchange period of the power conversion system on the power selling side, the power management system, and the power conversion system on the power buying side, according to the embodiment. [Figure 6] This is a timing chart illustrating an example of operation 2 of the power conversion system, power management system, and power conversion system on the power purchase side during the power exchange period, according to the embodiment. [Figure 7] This is a timing chart illustrating example 3 of the operation of the power conversion system, power management system, and power conversion system on the power purchase side during the power exchange period, according to the embodiment. [Figure 8] This is a timing chart illustrating an example of operation 4 of the power conversion system, power management system, and power conversion system on the power purchase side during the power exchange period, according to the embodiment. [Modes for carrying out the invention]

[0012] Figure 1 is a diagram illustrating the mechanism of power exchange between multiple distributed power systems 1. The multiple distributed power systems 1 are connected to a commercial power grid 2 (hereinafter simply referred to as grid 2), and power exchange between the multiple distributed power systems 1 is carried out via grid 2. In this embodiment, it is assumed that grid 2 installed by a general power transmission and distribution company is used as the transmission and distribution network. If the multiple distributed power systems 1 constitute a microgrid connected by private lines, power exchange is carried out using the private lines as the transmission and distribution network.

[0013] The distributed power system 1 comprises a solar cell 20, an on-board battery 30, and a power conversion system 10. The power conversion system 10 is an integrated power conversion system (also called a Power Station®) that combines the power conditioner function for the solar cell 20 and the power conditioner function for the on-board battery 30. The power conversion system 10 mainly comprises a first DC / DC converter 11, a second DC / DC converter 13, an inverter 12, and a control unit 15.

[0014] The solar cell 20 utilizes the photovoltaic effect to directly convert light energy into DC power. As the solar cell 20, heterojunction solar cells, polycrystalline silicon solar cells, monocrystalline silicon solar cells, thin-film silicon solar cells, compound semiconductor solar cells, etc., can be used.

[0015] The solar cell 20 is connected to the first DC / DC converter 11 and outputs the generated power to the first DC / DC converter 11. The first DC / DC converter 11 is connected between the solar cell 20 and the DC bus Bd and is a converter that can adjust the voltage of the DC power output from the solar cell 20. The first DC / DC converter 11 can be configured, for example, as a boost chopper.

[0016] The in-vehicle battery 30 is a drive battery mounted on an electric vehicle, and a lithium-ion battery, a nickel-hydrogen battery, etc. are used. The electric vehicle and the power conversion system 10 are connected by a charging cable. The in-vehicle battery 30 is connected to the second DC / DC converter 13 when the electric vehicle is parked at home, and charge and discharge control is performed by the second DC / DC converter 13. The second DC / DC converter 13 is connected between the in-vehicle battery 30 and the DC bus Bd, and is a bidirectional DC / DC converter that charges and discharges the in-vehicle battery 30 when the electric vehicle is parked at home. In addition, the second DC / DC converter 13 may be composed of an external V2H converter.

[0017] Note that instead of the in-vehicle battery 30, a configuration in which a stationary battery is connected to the power conversion system 10 may also be used. The in-vehicle or stationary battery can also be substituted with a capacitor such as an electric double layer capacitor or a lithium-ion capacitor. In this specification, the battery and the capacitor are collectively referred to as a power storage unit.

[0018] The inverter 12 is connected between the DC bus Bd and the distribution board 3. The first DC / DC converter 11 and the second DC / DC converter 13 are connected in parallel to the DC bus Bd. The inverter 12 converts the DC power supplied from at least one of the first DC / DC converter 11 and the second DC / DC converter 13 via the DC bus Bd into AC power, and outputs the converted AC power to the distribution board 3. At that time, the inverter 12 can control the voltage or current of the output AC power.

[0019] In addition, the inverter 12 can also convert the AC power supplied from the power grid 2 via the distribution board 3 into DC power, and output the converted DC power to the second DC / DC converter 13. The distribution board 3 serves as a power receiving point N for the power grid 2. The distributed power source system 1 and the in-house load 4 are connected to the distribution board 3. The in-house load 4 is a general term for the loads installed in the house.

[0020] Distribution board 3 includes a main circuit breaker, multiple branch circuit breakers, a main current sensor, a voltage sensor, multiple branch current sensors, and a measuring adapter. The main current sensor measures the power flow from system 2 to distribution board 3. Hereinafter, in this specification, the current flowing from system 2 to distribution board 3 is defined as positive, and the current flowing from distribution board 3 to system 2 is defined as negative.

[0021] Multiple branch current sensors measure the current flowing through each branch wiring. The measurement adapter collects data measured by the main current sensor, voltage sensor, and multiple branch current sensors. The measurement adapter calculates the power flow by multiplying the power flow current measured by the main current sensor by the voltage measured by the voltage sensor.

[0022] The measurement adapter is connected to the power conversion system 10 by wire or wireless. The measurement adapter is also connected to the Home Energy Management System 5 by wire or wireless. Note that the measurement adapter may be configured to be external rather than built into the distribution board 3. The power conversion system 10 is connected to the Home Energy Management System 5 by wire or wireless.

[0023] The in-home energy management system 5 is installed in the customer's home and monitors the supply and consumption of electricity within the home, providing centralized management of the home's energy. The in-home energy management system 5 can control the operating status of in-home loads 4 that have a function to cooperate with the in-home energy management system 5. Examples of in-home loads 4 whose operating status can be controlled include lighting, air conditioners, air purifiers, heat pump water heaters, and induction cooktops. To increase the power consumption of in-home loads 4, the in-home energy management system 5 can, for example, start the heating process of a heat pump water heater. Conversely, to decrease the power consumption of in-home loads 4, the in-home energy management system 5 can, for example, stop the heating process of a heat pump water heater.

[0024] The in-house energy management system 5 is connected to an external network 6 (e.g., the internet, a dedicated line, or a VPN (Virtual Private Network)) via a router device (not shown). The power management system 50 is connected to the external network 6.

[0025] The in-home energy management system 5 can accept electricity sales orders or electricity purchase orders from the user. Electricity is traded in 30-minute increments, for example. For electricity sales orders, the sales time period, electricity sales amount (XX kWh), and sales price (XX yen) are specified. For electricity purchase orders, the purchase time period, electricity purchase amount (XX kWh), and purchase price (XX yen) are specified. The user can input electricity sales orders or electricity purchase orders by operating the monitor of the in-home energy management system 5. Alternatively, the user may input electricity sales orders or electricity purchase orders by operating an information terminal (e.g., PC, tablet, smartphone) connected to the in-home energy management system 5 by wire or wireless connection.

[0026] Furthermore, electricity sales orders or electricity purchase orders may be automatically issued by an electricity trading agent implemented in the in-house energy management system 5 or information terminal. The electricity trading agent predicts future electricity demand through machine learning based on measurement data such as the amount of electricity generated by the solar cells 20, the state of charge (SOC) and charge / discharge amount of the vehicle battery 30, and the amount of electricity consumed by the in-house load 4. Based on the predicted electricity demand, the electricity trading agent issues electricity sales orders during periods of electricity surplus and electricity purchase orders during periods of electricity shortage.

[0027] The in-house energy management system 5 transmits a power sales order or a power purchase order to the power management system 50 via the external network 6. The in-house energy management system 5 also receives a contract notification from the power management system 50. The contract notification for a power sales order includes at least the power sales time period and the power flow setting value (hereinafter referred to as the power flow setting value). In the case of a power sales order, the power flow setting value will be a negative value. The contract notification for a power purchase order includes at least the power purchase time period and the power flow setting value. In the case of a power purchase order, the power flow setting value will be a positive value. The in-house energy management system 5 transmits the power sales time period or power purchase time period and the power flow setting value received from the power management system 50 to the power conversion system 10.

[0028] The control unit 15 comprehensively controls the entire power conversion system 10. The control unit 15 can be realized through the collaboration of hardware and software resources, or solely through hardware resources. Hardware resources that can be used include analog elements, microcontrollers, DSPs, ROMs, RAMs, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), and other LSIs. Software resources that can be used include programs such as firmware.

[0029] The control unit 15 can perform Maximum Power Point Tracking (MPPT) control of the solar cell 20 by controlling the first DC / DC converter 11. Specifically, the control unit 15 measures the input voltage and input current of the first DC / DC converter 11a, which are the output voltage and output current of the solar cell 20, and estimates the power generated by the solar cell 20. Based on the measured output voltage of the solar cell 20 and the estimated power generated, the control unit 15 generates a voltage command value to set the power generated by the solar cell 20 to its maximum power point (optimal operating point). For example, the control unit 15 searches for the maximum power point by changing the operating point voltage in predetermined step widths according to the hill-climbing method, and generates a voltage command value to maintain the maximum power point. The first DC / DC converter 11 switches in response to a drive signal based on the generated voltage command value.

[0030] The control unit 15 can control the charging and discharging of the on-board battery 30 by controlling the second DC / DC converter 13. The control unit 15 can communicate with the BMU (Battery Management Unit) of the on-board battery 30 via the communication line in the charging cable. In the case of CHAdeMO®, the connection is made via CAN (Controller Area Network). The second DC / DC converter 13 performs constant current (CC) discharge, constant voltage (CV) discharge, constant current charge, or constant voltage charge of the on-board battery 30 based on the current command value or voltage command value set by the control unit 15 or the BMU of the on-board battery 30.

[0031] The control unit 15 can control the inverter 12 so that the voltage of the DC bus Bd maintains a target value. Specifically, the control unit 15 measures the voltage of the DC bus Bd and generates a current command value to match the measured bus voltage to the target value. If the voltage of the DC bus Bd is higher than the target value, the control unit 15 generates a current command value to increase the output power of the inverter 12, and if the voltage of the DC bus Bd is lower than the target value, it generates a current command value to decrease the output power of the inverter 12. The inverter 12 switches according to the drive signal based on the generated current command value.

[0032] The control unit 15 can obtain the remaining capacity (SOC: State of Charge) of the vehicle battery 30 from the BMU of the vehicle battery 30. The control unit 15 can also obtain the power generated by the solar cell 20 from the solar cell 20. Furthermore, the control unit 15 can obtain the power flow Pd at the power receiving point N and the power consumption of the in-house load 4 from the distribution board 3.

[0033] The control unit 15 controls the power flow Pd at the power receiving point N to maintain the offset command value by performing at least one of the following during the period in which power exchange is carried out in accordance with power trading (hereinafter referred to as the power exchange period as appropriate): charge / discharge control of the onboard battery 30, power generation suppression control of the solar cell 20, and power consumption control of the in-house load 4. The offset command value is set based on the power flow setting value at the power receiving point N received from the power management system 50. Details of the offset command value will be described later.

[0034] The control unit 15 can perform charge and discharge control of the on-board battery 30 by controlling the second DC / DC converter 13. The control unit 15 can also perform power generation suppression control of the solar cell 20 by controlling the first DC / DC converter 11. Furthermore, the control unit 15 can perform power consumption control of the in-house load 4 via the in-house energy management system 5.

[0035] Figure 2 shows an example configuration of the power management system 50 according to the embodiment. The power management system 50 is built on a server installed in the company's own facilities or data center, or on a cloud server used under a cloud service contract, by a power trading service provider. The power management system 50 may be built on multiple servers distributed across multiple locations (data centers, company facilities). These multiple servers may be a combination of multiple company servers, a combination of multiple cloud servers, or a combination of a company server and a cloud server.

[0036] The power management system 50 comprises a processing unit 51, a storage unit 52, and a communication unit 53. The communication unit 53 is a communication interface (e.g., NIC: Network Interface Card) for connecting to an external network 6 by wired or wireless means.

[0037] The processing unit 51 includes an order acquisition unit 511, an order execution unit 512, a notification unit 513, a battery information acquisition unit 514, and a setting value change unit 515. The functions of the processing unit 51 can be realized through the cooperation of hardware resources and software resources, or solely through hardware resources. Hardware resources that can be used include a CPU, ROM, RAM, GPU (Graphics Processing Unit), ASIC, FPGA, and other LSIs. Software resources that can be used include operating systems and applications.

[0038] The storage unit 52 includes a non-volatile recording medium such as an HDD or SSD, and stores various types of data. In this embodiment, it mainly stores electricity transaction history.

[0039] The order acquisition unit 511 acquires multiple electricity sales orders and multiple electricity purchase orders from the energy management systems of multiple households or businesses that own distributed power generation systems 1 connected to grid 2, via an external network 6. In this embodiment, households eligible to participate in electricity trading bids are defined as households that own storage batteries. Therefore, even households that do not own power generation equipment such as solar panels can participate in electricity purchase bids. However, they are generally not eligible to participate in electricity sales bids. The eligibility requirements for businesses may be the same as those for households, or they may be determined individually with the electricity trading service provider.

[0040] The execution unit 512 matches multiple electricity sales orders and multiple electricity purchase orders for each time period covered by the transaction using a predetermined algorithm, and executes electricity transactions. The execution unit 512 basically executes orders where the electricity sales price and electricity purchase price match. The execution unit 512 can also execute transactions with a 1:N ratio of bidders. For example, it can execute an electricity sales order that is the sum of Household A's electricity sales order (1.5kWh) and Household B's electricity sales order (1.5kWh) and Household C's electricity purchase order (3.0kWh).

[0041] The contract unit 512 sets the power flow setting values ​​for the selling side and the buying side according to the contracted amount of electricity. For example, if 3.0 kWh of electricity is contracted for 30 minutes, the contract unit 512 sets the power flow setting value for the selling side to -1.5 kW and the power flow setting value for the buying side to +1.5 kW. If there are two electricity selling entities, the contract unit 512 sets the power flow setting value for each electricity selling entity to -0.75 kW.

[0042] In this manner, the contract unit 512 determines the power flow setting value for the selling side and the power flow setting value for the buying side for each power transaction, so that the power discharged from the distribution board 3 of the transmitting household or business to the grid 2 corresponds to the power drawn in from the grid 2 by the distribution board 3 of the receiving household or business (in this embodiment, the two are made to match).

[0043] The notification unit 513 notifies the energy management system of the household or business that issued the electricity sales order or electricity purchase order of the contract result. For the energy management system of the household or business where the electricity sales order or electricity purchase order was not completed, the notification unit 513 notifies the contract result of the uncompleted order. For the energy management system of the household or business where the electricity sales order or electricity purchase order was completed, the notification unit 513 notifies the contract result, which includes at least the time period for electricity sales or purchases and the power flow setting value.

[0044] During the power exchange period, the battery information acquisition unit 514 acquires battery information from the power conversion system 10 of the distributed power supply system 1 that is exchanging power, via the in-house energy management system 5.

[0045] The control unit 15 of the power conversion system 10 on the power selling side (transmission side) notifies the power management system 50 via the in-house energy management system 5 of the battery information if the remaining dischargeable capacity from the on-board battery 30 falls below a first specified value during the power selling period (reverse power flow period) in which power is being released to the grid 2. The control unit 15 includes the current remaining capacity of the on-board battery 30 in the battery information. Furthermore, the control unit 15 may also include the current power generated by the solar cells 20 and the power consumed by the in-house load 4 in the battery information.

[0046] The first specified value may be set to an amount of energy corresponding to a predetermined discharge-side SOC (e.g., 90%). Alternatively, the first specified value may be set to an agreed-upon amount of energy. When the first specified value is set to an agreed-upon amount of energy, if the power generated by the solar cell 20 is greater than the power consumed by the household load 4, the control unit 15 may omit notifying the power management system 50 of the battery information.

[0047] The setting value change unit 515 decreases the power flow setting value on the power selling side and the power flow setting value on the power buying side according to the battery information acquired by the battery information acquisition unit 514. If the first specified value is set to an amount of power corresponding to a predetermined discharge-side SOC, the setting value change unit 515 changes the power flow setting value on the power selling side to a power value obtained, for example, by dividing the remaining capacity of the onboard battery 30 by the remaining time of the power exchange period. Alternatively, it may be changed to a power value obtained by subtracting a predetermined margin from that power value.

[0048] The setting value change unit 515 may change the power flow setting value on the power selling side to a power value obtained by dividing {remaining capacity of the onboard battery 30 + (power generated by the solar cell 20 × remaining time) - (power consumption of the household load 4 × remaining time)} by the remaining time. Alternatively, it may be changed to a power value obtained by subtracting a predetermined margin from this power value.

[0049] The setting value changing unit 515 changes the power flow setting value on the power purchase side in accordance with the change in the power flow setting value on the power selling side. Specifically, the setting value changing unit 515 decreases the power flow setting value on the power purchase side by the same amount in absolute value as the power flow setting value on the power selling side.

[0050] If the first specified value is set to the agreed-upon amount of electricity, the setting value changing unit 515 reduces, for example, the power flow setting value on the selling side and the power flow setting value on the buying side to half their respective values. Note that the reduction amount of the power flow setting value on the selling side and the power flow setting value on the buying side may be set to a smaller amount the shorter the remaining time of the power exchange period.

[0051] The notification unit 154 notifies the power conversion system 10 on the power selling side of the changed power flow setting value and notifies the power conversion system 10 on the power buying side of the changed power flow setting value.

[0052] The control unit 15 of the power conversion system 10 on the power purchasing (receiving) side notifies the power management system 50 via the in-house energy management system 5 of the battery information if the available capacity that can be charged to the on-board battery 30 falls below the second specified value during the power purchasing period (forward power flow period) when power is drawn in from grid 2. The control unit 15 includes the current available capacity of the on-board battery 30 in the battery information. Furthermore, the control unit 15 may also include the current power generated by the solar cells 20 and the power consumed by the in-house load 4 in the battery information.

[0053] The second specified value may be set to an amount of energy corresponding to a predetermined charging state of charge (e.g., 10%). Alternatively, the second specified value may be set to an agreed-upon amount of energy. When the second specified value is set to an agreed-upon amount of energy, if the power generated by the solar cell 20 is less than the power consumed by the household load 4, the control unit 15 may omit notifying the power management system 50 of the battery information.

[0054] The setting value change unit 515 decreases the power flow setting value on the power selling side and the power flow setting value on the power buying side according to the battery information acquired by the battery information acquisition unit 514. If the second specified value is set to an amount of power corresponding to a predetermined charging side SOC, the setting value change unit 515 changes the power flow setting value on the power buying side to a power value obtained by dividing the available capacity of the onboard battery 30 by the remaining time of the power exchange period, for example. Alternatively, it may be changed to a power value obtained by subtracting a predetermined margin from that power value.

[0055] The setting value change unit 515 may change the power flow setting value on the power purchase side to a power value obtained by dividing {available capacity of the on-board battery 30 - (power generated by the solar cell 20 × remaining time) + (power consumption of the household load 4 × remaining time)} by the remaining time. Alternatively, it may be changed to a power value obtained by subtracting a predetermined margin from this power value.

[0056] The setting value changing unit 515 changes the power flow setting value on the power selling side in accordance with the change in the power flow setting value on the power purchasing side. Specifically, the setting value changing unit 515 decreases the power flow setting value on the power selling side by the same amount in absolute value as the power flow setting value on the power purchasing side.

[0057] If the second specified value is set to the agreed-upon amount of electricity, the setting value changing unit 515 reduces, for example, the power flow setting value on the purchasing side and the power flow setting value on the selling side to half their respective values. Note that the reduction amount of the power flow setting value on the purchasing side and the power flow setting value on the selling side may be set to a smaller amount the shorter the remaining time of the power exchange period.

[0058] The notification unit 154 notifies the power conversion system 10 on the power purchase side of the changed power flow setting value and notifies the power conversion system 10 on the power selling side of the changed power flow setting value.

[0059] The control unit 15 of the power conversion system 10 on the power selling side notifies the power management system 50 via the in-house energy management system 5 of the battery information if the discharge power from the vehicle battery 30 exceeds the third specified value during the period when power is being sold to grid 2. The control unit 15 includes the current discharge power from the vehicle battery 30 and the third specified value in the battery information.

[0060] The default value of the third specified value is set based on the discharge rated power of the second DC / DC converter 13. For example, if the discharge rated power of the second DC / DC converter 13 is 6.0 kW, it is set to 5.5 kW, which is 6.0 kW minus a predetermined margin (e.g., 0.5 kW).

[0061] The control unit 15 determines the maximum discharge rate of the on-board battery 30 by referring to a table describing the relationship between SOC and the maximum discharge rate. The maximum discharge rate for each SOC of the on-board battery 30 varies depending on the type and capacity of the on-board battery 30. The designer prepares the above table in advance according to the on-board battery 30 to be used. The maximum discharge rate of the on-board battery 30 is 0W when SOC = 0%. The maximum discharge rate increases as SOC increases. For simplicity, the maximum discharge rate may be fixed to the discharge rated power of the on-board battery 30 in the range of SOC = 2-100%. If the absolute value of the maximum discharge rate is greater than the default value of the third specified value, the control unit 15 changes the third specified value to the absolute value of the maximum discharge rate.

[0062] The setting value change unit 515 changes the power flow setting value on the power selling side to the third specified value based on the battery information received from the power conversion system 10 on the power selling side. Alternatively, it may be changed to a power value obtained by subtracting a predetermined margin from the third specified value. The setting value change unit 515 changes the power flow setting value on the power buying side in accordance with the change in the power flow setting value on the power selling side. The notification unit 154 notifies the power conversion system 10 on the power selling side of the changed power flow setting value on the power selling side and notifies the power conversion system 10 on the power buying side of the changed power flow setting value on the power buying side.

[0063] The control unit 15 of the power conversion system 10 on the electricity purchasing side notifies the power management system 50 via the in-house energy management system 5 of the battery information if the charging power to the vehicle battery 30 exceeds the fourth specified value during the period when electricity is being drawn from grid 2. The control unit 15 includes the current charging power to the vehicle battery 30 and the fourth specified value in the battery information.

[0064] The default value of the fourth specified value is set based on the charging rated power of the second DC / DC converter 13. For example, if the charging rated power of the second DC / DC converter 13 is 6.0 kW, it is set to 5.5 kW, which is 6.0 kW minus a predetermined margin (e.g., 0.5 kW).

[0065] The control unit 15 determines the maximum charge rate of the on-board battery 30 by referring to a table describing the relationship between SOC and the maximum charge rate. The maximum charge rate for each SOC of the on-board battery 30 varies depending on the type and capacity of the on-board battery 30. The designer prepares the above table in advance according to the on-board battery 30 to be used. The maximum charge rate of the on-board battery 30 is 0W when SOC = 100%. The maximum charge rate increases as the SOC decreases. For simplicity, the maximum charge rate may be fixed to the charging rated power of the on-board battery 30 in the range of SOC = 98-0%. If the absolute value of the maximum charge rate is greater than the default value of the fourth specified value, the control unit 15 changes the fourth specified value to the absolute value of the maximum charge rate.

[0066] The setting value change unit 515 changes the power flow setting value on the power purchase side to the fourth specified value based on the battery information received from the power conversion system 10 on the power purchase side. Alternatively, it may be changed to a power value obtained by subtracting a predetermined margin from the fourth specified value. The setting value change unit 515 changes the power flow setting value on the power sales side in accordance with the change in the power flow setting value on the power purchase side. The notification unit 154 notifies the power conversion system 10 on the power purchase side of the changed power flow setting value and notifies the power conversion system 10 on the power sales side of the changed power flow setting value.

[0067] Figure 3 is a diagram illustrating specific examples of the power conversion system 10a on the selling side and the power conversion system 10b on the buying side during the power exchange period according to this embodiment. In this embodiment, the power conversion system 10 is operated in offset setting mode during the power exchange period. The offset setting mode is a mode in which the onboard battery 30 is charged and discharged so that the power flow Pd maintains an offset command value (other than 0W). The power flow setting value notified from the power management system 50 is used as the offset command value.

[0068] In the environmental priority mode of the power conversion system 10, load-following control using the on-board battery 30 is performed so that the power flow Pd becomes 0W. When the solar cell 20 is not generating power, the control unit 15 controls the discharge power from the on-board battery 30 so that the discharge power from the on-board battery 30 is equal to the power consumption of the household load 4. When the discharge power from the on-board battery 30 is equal to the power consumption of the household load 4, the power flow Pd becomes 0W. When the solar cell 20 is generating power, the control unit 15 controls the charge and discharge power of the on-board battery 30 so that (power generated by the solar cell 20 + charge and discharge power of the on-board battery 30) is equal to the power consumption of the household load 4. When (power generated by the solar cell 20 + charge and discharge power of the on-board battery 30) is equal to the power consumption of the household load 4, the power flow Pd becomes 0W.

[0069] In contrast, in offset setting mode, load following control using the on-board battery 30 is performed so that the power flow Pd becomes equal to the offset command value (other than 0W). The following explanation assumes the power selling side. When the solar cell 20 is not generating power, the control unit 15 controls the discharge power from the on-board battery 30 so that the discharge power from the on-board battery 30 is equal to (the power consumption of the household load 4 + |power flow power|). When the difference between the discharge power from the on-board battery 30 and the power consumption of the household load 4 is equal to the |offset setting value|, the power flow becomes equal to the offset command value. When the solar cell 20 is generating power, the control unit 15 controls the charge and discharge power of the on-board battery 30 so that (the power generated by the solar cell 20 + the charge and discharge power of the on-board battery 30) is equal to (the power consumption of the household load 4 + |power flow power|). When the difference between (the power generated by solar panel 20 + the charging and discharging power of vehicle battery 30) and the power consumption of household load 4 is equal to the |offset setting value|, the power flow becomes equal to the offset command value.

[0070] The example shown in Figure 3 illustrates a scenario where the offset setting for the power selling side is -3.0kW and the offset setting for the power buying side is +3.0kW. For example, if the power generated by the solar panel 20a on the power selling side decreases from 1.5kW to 1.0kW due to fluctuations in solar radiation, the discharge power of the on-board battery 30a on the power selling side is increased from 4.0kW to 4.5kW. Conversely, if the power generated by the solar panel 20a on the power selling side increases from 1.5kW to 2.0kW due to fluctuations in solar radiation, the discharge power of the on-board battery 30a on the power selling side is decreased from 4.0kW to 3.5kW. For example, if the power consumption of the household load 4a on the power selling side decreases from 2.5kW to 2.0kW due to load fluctuations, the discharge power of the on-board battery 30a on the power selling side is decreased from 4.0kW to 3.5kW. Conversely, if the power consumption of the home load 4a on the power selling side increases from 2.5kW to 3.0kW due to load fluctuations, the discharge power of the vehicle battery 30a on the power selling side will be increased from 4.0kW to 4.5kW. Through this control, the offset setting value on the power selling side will be maintained at -3.0kW.

[0071] Furthermore, if it is not possible to increase the discharge power from the vehicle battery 30a due to limitations in the remaining capacity of the vehicle battery 30a, and if it is possible to reduce the power consumption of the household load 4a, the control unit 15 will reduce the power consumption of the household load 4a. If it is not possible to reduce the power consumption of the household load 4a, or if reducing the power consumption of the household load 4a alone is not enough to maintain the power flow at the offset command value, the control unit 15 will suppress the power generated by the solar cell 20a. Since suppressing the power generation of the solar cell 20a is a control that wastes energy, it is set to the lowest priority among the controls for maintaining the power flow at the offset command value.

[0072] For example, if the power generated by the solar panel 20b on the electricity-purchasing side decreases from 1.5 kW to 1.0 kW due to fluctuations in solar radiation, the charging power of the vehicle-mounted battery 30b on the electricity-purchasing side will be reduced from 3.0 kW to 2.5 kW. Conversely, if the power generated by the solar panel 20b on the electricity-purchasing side increases from 1.5 kW to 2.0 kW due to fluctuations in solar radiation, the charging power of the vehicle-mounted battery 30b on the electricity-purchasing side will be increased from 3.0 kW to 3.5 kW. For example, if the power consumption of the household load 4b on the electricity-purchasing side decreases from 1.5 kW to 1.0 kW due to load fluctuations, the charging power of the vehicle-mounted battery 30b on the electricity-purchasing side will be increased from 3.0 kW to 3.5 kW. Conversely, if the power consumption of the household load 4b on the electricity-purchasing side increases from 1.5 kW to 2.0 kW due to load fluctuations, the charging power of the vehicle-mounted battery 30b on the electricity-purchasing side will be reduced from 3.0 kW to 2.5 kW. Through the above control, the offset setting value on the power purchase side is maintained at 3.0kW.

[0073] Furthermore, if it is not possible to increase the charging power to the vehicle battery 30b due to limitations in the available capacity of the vehicle battery 30b, and if it is possible to control the increase in power consumption of the household load 4b, the control unit 15 will increase the power consumption of the household load 4b. For example, it will start heating the water using a heat pump water heater. If it is not possible to control the increase in power consumption of the household load 4b, or if the power flow cannot be maintained at the offset command value by controlling the increase in power consumption of the household load 4b alone, the control unit 15 will suppress the power generated by the solar cell 20b.

[0074] Figure 4 is a flowchart illustrating the basic operation of the power management system 50 according to the embodiment regarding power trading. The order acquisition unit 511 acquires multiple power sales orders and multiple power purchase orders from the energy management systems of multiple households or businesses, each owning a distributed power source system 1 (S1). The contracting unit 512 matches the multiple power sales orders and multiple power purchase orders for each time period subject to trading and concludes the power transaction (S2). The contracting unit 512 determines the power flow setting value for the power sales side and the power flow setting value for the power purchase side according to the agreed-upon amount of power (S3). The notification unit 513 notifies the power conversion system 10 on the power sales side of the power flow setting value for the power sales side (S4) and notifies the power conversion system 10 on the power purchase side of the power purchase side of the power flow setting value for the power purchase side (S5).

[0075] Figure 5 is a timing chart illustrating an example of operation 1 during the power exchange period of the power conversion system 10a on the power selling side, the power management system 50, and the power conversion system 10b on the power buying side, according to an embodiment. The control unit 15a of the power conversion system 10a on the power selling side sets the power flow setting value on the power selling side, received from the power management system 50, to the offset command value. As the power selling period begins, the control unit 15a starts offset operation (S10) to maintain the power flow Pd at the power receiving point Na at the offset command value. The offset operation continues until the power selling period ends (Y in S11) (N in S11).

[0076] The control unit 15b of the power conversion system 10b on the power purchase side sets the power flow setting value on the power purchase side, received from the power management system 50, to the offset command value. As the power purchase period begins, the control unit 15b starts offset operation (S30) to maintain the power flow Pd at the power receiving point Nb at the offset command value. The offset operation continues until the power purchase period ends (Y in S31) (N in S31).

[0077] The control unit 15a of the power conversion system 10a on the power selling side notifies the power management system 50 of the battery information, including the current remaining capacity, when the remaining dischargeable capacity from the on-board battery 30a falls below a first specified value (Y in S12) (S13). The setting value change unit 515 of the power management system 50 changes the power flow setting value on the power selling side and the power flow setting value on the power buying side according to the battery information received from the power conversion system 10a on the power selling side (S20). The notification unit 154 of the power management system 50 notifies the power conversion system 10a on the power selling side of the changed power flow setting value on the power selling side and notifies the power conversion system 10b on the power buying side of the changed power flow setting value on the power buying side (S21).

[0078] The control unit 15a of the power conversion system 10a on the power selling side sets the modified power flow setting value on the power selling side, received from the power management system 50, as the new offset command value (S14). The process then proceeds to step S11. The control unit 15b of the power conversion system 10b on the power buying side sets the modified power flow setting value on the power buying side, received from the power management system 50, as the new offset command value (S34). The process then proceeds to step S31.

[0079] Furthermore, during the period when the remaining dischargeable capacity from the onboard battery 30a falls below the first specified value, the control unit 15a of the power conversion system 10a on the power selling side may periodically (for example, at 1-minute intervals or 5-minute intervals) notify the power management system 50 of the battery information, or it may notify the battery information only once.

[0080] Furthermore, if the relationship (power generated by solar cell 20a > power consumed by household load 4a) persists and the remaining dischargeable capacity from the vehicle battery 30a recovers to the first specified value, the control unit 15a may notify the power management system 50 of the battery information, including the recovered remaining capacity. In this case, the setting value change unit 515 of the power management system 50 resets the power flow setting values ​​for the power selling side and the power flow setting values ​​for the power buying side to their initial values, and the notification unit 154 notifies the power conversion system 10a on the power selling side of the changed power flow setting value and the power conversion system 10b on the power buying side of the changed power flow setting value.

[0081] Furthermore, if the relationship (power generated by solar cell 20a < power consumption of household load 4a) persists and the remaining dischargeable capacity from the vehicle battery 30a reaches the discharge limit, the control unit 15a notifies the power management system 50 of a message indicating that the discharge limit has been reached. In this case, the setting value change unit 515 of the power management system 50 changes the power flow setting value on the selling side and the power flow setting value on the buying side to 0W, and the notification unit 154 notifies the power conversion system 10a on the selling side of the changed power flow setting value on the selling side and the power conversion system 10b on the buying side of the changed power flow setting value on the buying side.

[0082] Furthermore, in the contract section 512, if there is a period during the power exchange period in which the power flow setting values ​​for the selling side and the power flow setting values ​​for the buying side are lower than the power flow setting values ​​corresponding to the contracted amount of electricity, the selling price and the buying price will be reduced by the amount of the reduction. In this case, a penalty fee may be imposed on the selling side.

[0083] Figure 6 is a timing chart illustrating an example of operation 2 during the power exchange period of the power conversion system 10a on the power selling side, the power management system 50, and the power conversion system 10b on the power buying side, according to the embodiment. Explanations of processes common to operation example 1 shown in Figure 5 will be omitted as appropriate.

[0084] The control unit 15b of the power conversion system 10b on the power purchasing side notifies the power management system 50 of the battery information, including the current available capacity, when the available capacity of the on-board battery 30b falls below the second specified value (Y in S32) (S33). The setting value changing unit 515 of the power management system 50 changes the power flow setting value on the power selling side and the power flow setting value on the power purchasing side according to the battery information received from the power conversion system 10b on the power purchasing side (S20). The following process is the same as operation example 1 shown in Figure 5.

[0085] Furthermore, during periods when the available chargeable capacity of the onboard battery 30b falls below the second specified value, the control unit 15b of the power conversion system 10b on the power purchase side may periodically (for example, at 1-minute intervals or 5-minute intervals) notify the power management system 50 of the battery information, or it may notify the battery information only once.

[0086] Furthermore, if the relationship (power generated by solar cell 20b < power consumed by household load 4b) continues and the available capacity that can be charged to the vehicle battery 30b recovers to the second specified value, the control unit 15b may notify the power management system 50 of the battery information including the recovered available capacity. In this case, the setting value change unit 515 of the power management system 50 returns the power flow setting value on the selling side and the power flow setting value on the buying side to their initial values, and the notification unit 154 notifies the power conversion system 10a on the selling side of the changed power flow setting value on the selling side and notifies the power conversion system 10b on the buying side of the changed power flow setting value on the buying side.

[0087] Furthermore, if the relationship (power generated by solar cell 20b > power consumption of household load 4b) persists and the available capacity to be charged in the vehicle battery 30b reaches the charging limit, the control unit 15b notifies the power management system 50 of a message indicating that the charging limit has been reached. In this case, the setting value change unit 515 of the power management system 50 changes the power flow setting value on the selling side and the power flow setting value on the buying side to 0W, and the notification unit 154 notifies the power conversion system 10a on the selling side of the changed power flow setting value on the selling side and the power conversion system 10b on the buying side of the changed power flow setting value on the buying side.

[0088] Furthermore, in the contract section 512, if there is a period during the power exchange period in which the power flow setting values ​​for the selling side and the power flow setting values ​​for the buying side are lower than the power flow setting values ​​corresponding to the contracted amount of electricity, the selling price and the buying price will be reduced by the amount of the reduction. In this case, a penalty fee may be imposed on the buying side.

[0089] Figure 7 is a timing chart illustrating Example 3 of operation during the power exchange period of the power conversion system 10a on the power selling side, the power management system 50, and the power conversion system 10b on the power purchasing side, according to the embodiment. Explanations of processes common to Example 1 shown in Figure 5 will be omitted as appropriate.

[0090] The control unit 15a of the power conversion system 10a on the power selling side notifies the power management system 50 of the battery information, including the current discharge power and the third specified value, when the discharge power from the on-board battery 30a exceeds the third specified value (Y in S12a) (S13). The setting value change unit 515 of the power management system 50 changes the power flow setting value on the power selling side and the power flow setting value on the power buying side according to the battery information received from the power conversion system 10a on the power selling side (S20). The notification unit 154 of the power management system 50 notifies the power conversion system 10a on the power selling side of the changed power flow setting value on the power selling side and notifies the power conversion system 10b on the power buying side of the changed power flow setting value on the power buying side (S21).

[0091] The control unit 15a of the power conversion system 10a on the power sales side sets the modified power flow setting value on the power sales side, received from the power management system 50, to the new offset command value (S14). The control unit 15a identifies the maximum discharge rate of the on-board battery 30a according to the State of Charge (SOC) of the on-board battery 30a (S15). The control unit 15a compares the identified maximum discharge rate of the on-board battery 30a with the default value of the third specified value (S16). If the maximum discharge rate is greater than the default value of the third specified value (Y in S16), the control unit 15a updates the third specified value to the value of the maximum discharge rate of the on-board battery 30a (S17). Alternatively, it may be updated to a value obtained by subtracting a predetermined margin from the maximum discharge rate of the on-board battery 30a. If the maximum discharge rate is less than the default value of the third specified value (N in S16), it is not changed from the default value. The process proceeds to step S11.

[0092] Furthermore, in the contract section 512, if there is a period during the power exchange period in which the power flow setting values ​​for the selling side and the power flow setting values ​​for the buying side are lower than the power flow setting values ​​corresponding to the contracted amount of electricity, the selling price and the buying price will be reduced by the amount of the reduction. In this case, a penalty fee may be imposed on the selling side.

[0093] Figure 8 is a timing chart illustrating an example of operation 4 during the power exchange period of the power conversion system 10a on the power selling side, the power management system 50, and the power conversion system 10b on the power buying side, according to the embodiment. Explanations of processes common to operation example 1 shown in Figure 5 will be omitted as appropriate.

[0094] The control unit 15b of the power conversion system 10b on the power purchasing side notifies the power management system 50 of the battery information, including the current charging power and the fourth specified value, when the charging power to the on-board battery 30b exceeds the fourth specified value (Y in S32a) (S33). The setting value change unit 515 of the power management system 50 changes the power flow setting value on the power selling side and the power flow setting value on the power purchasing side according to the battery information received from the power conversion system 10b on the power purchasing side (S20). The notification unit 154 of the power management system 50 notifies the power conversion system 10a on the power selling side of the changed power flow setting value on the power selling side and notifies the power conversion system 10b on the power purchasing side of the changed power flow setting value on the power purchasing side (S21).

[0095] The control unit 15b of the power conversion system 10b on the power purchase side sets the modified power flow setting value on the power purchase side received from the power management system 50 to the new offset command value (S34). The control unit 15b identifies the maximum charge rate of the on-board battery 30b according to the State of Charge (SOC) of the on-board battery 30b (S35). The control unit 15b compares the identified maximum charge rate of the on-board battery 30b with the default value of the fourth specified value (S36). If the maximum charge rate is greater than the default value of the fourth specified value (Y in S36), the control unit 15b updates the fourth specified value to the value of the maximum charge rate of the on-board battery 30b (S37). Alternatively, it may be updated to a value obtained by subtracting a predetermined margin from the maximum charge rate of the on-board battery 30b. If the maximum charge rate is less than the default value of the fourth specified value (N in S36), it is not changed from the default value. The process proceeds to step S31.

[0096] Furthermore, in the contract section 512, if there is a period during the power exchange period in which the power flow setting values ​​for the selling side and the power flow setting values ​​for the buying side are lower than the power flow setting values ​​corresponding to the contracted amount of electricity, the selling price and the buying price will be reduced by the amount of the reduction. In this case, a penalty fee may be imposed on the buying side.

[0097] As described above, this embodiment makes it possible to satisfy the principle of simultaneous and equal supply in power exchange between multiple distributed power systems 1 with high quality. That is, by matching the power flow from the power receiving point Na on the selling side to the grid 2 with the power flow from the grid 2 to the power receiving point Nb on the purchasing side, it is possible to prevent surplus or deficit power from occurring in the grid 2 due to power exchange between the distributed power systems 1.

[0098] In contrast, if the control targets are the discharge rate of the battery on the power-selling side and the charge rate of the battery on the power-buying side, changes in the power generated by the solar panels or changes in the power consumption of the load may result in a surplus or deficit of power in grid 2 due to power exchange. In other words, there may be periods when the principle of simultaneous supply and demand cannot be satisfied.

[0099] In contrast, in this embodiment, by controlling the power flow at the power receiving point Na on the selling side and the power flow at the power receiving point Nb on the buying side, the principle of simultaneous and equal supply can be satisfied at every moment. Therefore, the impact on grid 2 due to power exchange between distributed power systems 1 can be minimized, and the stability of grid 2 can be maintained.

[0100] Furthermore, if the remaining capacity of the on-board battery 30a on the power-selling side is running low, or if the available capacity of the on-board battery 30b on the power-buying side is running low, the power flow setting can be reduced to allow power exchange to continue for as long as possible.

[0101] Furthermore, if the discharge power from the on-board battery 30a on the power-selling side approaches the rated value, or if the charging power to the on-board battery 30b on the power-buying side approaches the rated value, the power flow setting can be reduced to allow power exchange to continue for as long as possible.

[0102] The present disclosure has been described above based on embodiments. The embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications are also within the scope of the present disclosure.

[0103] In the above embodiment, an example was described in which a solar cell 20 is used as a power generation device that converts renewable energy into electrical energy. However, a wind turbine or a micro-hydroelectric generator can also be used instead of the solar cell 20. In this case, a rectifier is connected between the wind turbine or micro-hydroelectric generator and the first DC / DC converter 11.

[0104] In the above embodiment, a power conversion system 10 to which either an on-board battery 30 or a stationary battery is connected has been described, but a power conversion system 10 to which both an on-board battery 30 and a stationary battery are connected may also be used. In that case, a DC / DC converter for the on-board battery 30 and a DC-DC converter for the stationary battery are provided in parallel with the DC bus Bd. The control unit 15 can use the sum of the remaining capacity of the on-board battery 30 and the remaining capacity of the stationary battery as the remaining capacity for offset operation when selling electricity. The control unit 15 can also use the sum of the unused capacity of the on-board battery 30 and the unused capacity of the stationary battery as the unused capacity for offset operation when purchasing electricity.

[0105] In the above embodiment, the control unit 15 controlled the power flow Pd at the power receiving point N to maintain the offset command value (power value), but it may also control the power flow current at the power receiving point N to maintain the offset command value (current value).

[0106] In the above embodiment, the exchange of power between distributed power systems 1 due to power trading was described. In this regard, the offset operation according to this embodiment can also be used for power exchange that does not involve monetary transactions, with the aim of effectively utilizing the solar cells 20 and storage batteries among multiple distributed power systems 1 that form a single group.

[0107] The subject of the system or method in this disclosure comprises a computer. The functions of the subject of the system or method in this disclosure are realized by the computer executing a program. The computer comprises a processor as its main hardware component, which operates according to the program. The processor is of any type as long as it can realize its functions by executing a program. The processor consists of one or more electronic circuits, including semiconductor integrated circuits (ICs) or LSIs (largescale integrations). Here, we refer to them as ICs and LSIs, but the name changes depending on the degree of integration, and they may also be called system LSIs, VLSIs (very large scale integrations), or ULSIs (ultra large scale integrations). Field-programmable gate arrays (FPGAs) that are programmed after the manufacture of the LSI, or reconfigurable logic devices that allow for the reconfiguration of junction relationships within the LSI or the setup of circuit compartments within the LSI, can also be used for the same purpose. Multiple electronic circuits may be integrated on a single chip or provided on multiple chips. Multiple chips may be aggregated in a single device or provided in multiple devices. The program is recorded on a non-temporary recording medium such as a computer-readable ROM, optical disc, or hard disk drive. The program may be pre-stored on the recording medium or supplied to the recording medium via a wide-area communication network, including the Internet.

[0108] The embodiments may be specified by the following items.

[0109] [Item 1] A power management system (50) that manages the exchange of power between multiple distributed power systems (1) connected to the same power transmission and distribution network (2), Each distributed power system (1) has a power storage unit (30) and a power conversion system (10), The power conversion system (10) is capable of controlling the power flow value between the distribution board (3) to which the distributed power supply system (1) and the load (4) are connected and the power transmission and distribution network (2) so that it becomes a set value. The aforementioned power management system (50) is When power is exchanged between multiple distributed power systems (1) via the aforementioned power transmission and distribution network (2), the power released from the power transmission side distribution board (3) to the power transmission and distribution network (2) and the power drawn in by the power receiving side distribution board (3) from the power transmission and distribution network (2) match To that end, the system includes a notification unit (513) that notifies the power transmission power conversion system (10) of the set value of the power flow value on the power transmission side, and notifies the power reception power conversion system (10) of the set value of the power flow value on the power reception side. Power management system (50). According to this, the principle of simultaneous and equal supply can be satisfied moment by moment in the exchange of power between multiple distributed power systems (1). [Item 2] At least one of the aforementioned multiple distributed power systems (1) includes a power generation device (20) that converts renewable energy into electrical energy, The power conversion system (10) controls the power flow value to the set value by performing at least one of the following: charge / discharge control of the energy storage unit (30), power generation suppression control of the power generation device (20), and power consumption control of the load (4). The power management system described in item 1 (50). According to this, the power flow value can be maintained at the set value regardless of changes in generated power or changes in the power consumption of the load (4). [Item 3] An information acquisition unit (514) acquires information about the energy storage unit that is notified by the power conversion system (10) on the power transmission side when the remaining dischargeable capacity from the energy storage unit (30) of the distributed power system (1) on the power transmission side falls below a specified value, The system further includes a setting value changing unit (515) that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit (513) notifies the power conversion system (10) on the power transmission side and the power conversion system (10) on the power reception side of the changed setting value. Power management system as described in item 1 or 2 (50). According to this, even when the remaining capacity of the power transmission side's energy storage unit (30) is running low, power exchange can be continued as much as possible. [Item 4] An information acquisition unit (514) acquires information about the energy storage unit that is notified by the power conversion system (10) on the receiving side when the available capacity that can be charged in the energy storage unit (30) of the distributed power supply system (1) on the receiving side falls below a specified value, The system further includes a setting value changing unit (515) that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit (513) notifies the power transmission side power conversion system (10) and the power receiving side power conversion system (10) of the changed setting value. Power management system as described in item 1 or 2 (50). According to this, even when the available capacity of the receiving side's energy storage unit (30) is running low, power exchange can be continued as much as possible. [Item 5] An information acquisition unit (514) acquires information about the energy storage unit that is notified by the power conversion system (10) on the power transmission side when the discharge power from the energy storage unit (30) of the distributed power system (1) on the power transmission side exceeds a specified value based on the discharge rated power, The system further includes a setting value changing unit (515) that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit (513) notifies the power transmission side power conversion system (10) and the power receiving side power conversion system (10) of the changed setting value. Power management system as described in item 1 or 2 (50). According to this, even when the discharge power from the power storage unit (30) on the transmission side is approaching its rated value, power exchange can be continued as much as possible. [Item 6] An information acquisition unit (514) acquires information about the energy storage unit that is notified by the power conversion system (10) on the receiving side when the power charged to the energy storage unit (30) of the distributed power supply system (1) on the receiving side exceeds a specified value based on the rated charging power, The system further includes a setting value changing unit (515) that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit (513) notifies the power transmission side power conversion system (10) and the power receiving side power conversion system (10) of the changed setting value. Power management system as described in item 1 or 2 (50). According to this, even when the charging power to the receiving side's energy storage unit (30) is approaching its rated value, power exchange can be continued as much as possible. [Item 7] A power conversion system (10) included in a distributed power supply system (1) having an energy storage unit (30), The distributed power supply system (1) and the load (4) are connected to a distribution board (3), and a control unit (15) is provided that can control the power flow value between the distribution board (3) and the power transmission and distribution network (2) so that it becomes a set value. The control unit (15) When power is exchanged between multiple distributed power systems (1) via the aforementioned power transmission and distribution network (2), the power released from the power transmission side distribution board (3) to the power transmission and distribution network (2) and the power drawn in by the power receiving side distribution board (3) from the power transmission and distribution network (2) match To that end, the power management system (50) notifies the power conversion system (10) on the power transmission side of the set value of the power flow value on the power transmission side, and notifies the power conversion system (10) on the power reception side of the set value of the power flow value on the power reception side, and obtains the set value of the power flow value from the power management system (50) on the power reception side. The current value is controlled to become the acquired set value. electric Force conversion system (10). According to this, the principle of simultaneous and equal supply can be satisfied moment by moment in the exchange of power between multiple distributed power systems (1). [Item 8] The distributed power system (1) includes a power generation device (20) that converts renewable energy into electrical energy, The control unit (15) controls the power flow value to the set value by performing at least one of the following: charge / discharge control of the energy storage unit (30), power generation suppression control of the power generation device (20), and power consumption control of the load (4). The power conversion system (10) described in item 7. According to this, the power flow value can be maintained at the set value regardless of changes in generated power or changes in the power consumption of the load (4). [Item 9] The control unit (15) During the power exchange period in which power is being released to the power transmission and distribution network (2), if the remaining dischargeable capacity from the energy storage unit (30) falls below a specified value, the energy storage unit information is notified to the power management system (50). The power management system (50) obtains the changed power flow value setting, The power flow value is controlled to become the acquired modified setting value. A power conversion system (10) as described in item 7 or 8. According to this, even when the remaining capacity of the power transmission side's energy storage unit (30) is running low, power exchange can be continued as much as possible. [Item 10] The control unit (15) During the power exchange period in which power is being received from the aforementioned power transmission and distribution network (2), if the available capacity that can be charged in the energy storage unit (30) falls below a specified value, the energy storage unit information is notified to the power management system (50), The power management system (50) obtains the changed power flow value setting, The power flow value is controlled to become the acquired modified setting value. A power conversion system (10) as described in item 7 or 8. According to this, even when the available capacity of the receiving side's energy storage unit (30) is running low, power exchange can be continued as much as possible. [Item 11] The control unit (15) During the power exchange period in which power is being released to the power transmission and distribution network (2), if the discharge power from the energy storage unit (30) exceeds a specified value based on the discharge rated power, the energy storage unit information is notified to the power management system (50). The power management system (50) acquires the changed power flow value setting, The power flow value is controlled to become the acquired modified setting value. A power conversion system (10) as described in item 7 or 8. According to this, even when the discharge power from the power storage unit (30) on the transmission side is approaching its rated value, power exchange can be continued as much as possible. [Item 12] The control unit (15) During the power exchange period in which power is received from the aforementioned power transmission and distribution network (2), if the power charged to the energy storage unit (30) exceeds a specified value based on the charging rated power, the energy storage unit information is notified to the power management system (50). The power management system (50) obtains the changed power flow value setting, The power flow value is controlled to become the acquired modified setting value. A power conversion system (10) as described in item 7 or 8. According to this, even when the charging power to the receiving side's energy storage unit (30) is approaching its rated value, power exchange can be continued as much as possible. [Explanation of Symbols]

[0110] 1 Distributed power supply system, 2 grid, 3 distribution board, 4 In-house load, 5 In-house energy management system, 6 External network, 10 Power conversion system, 20 Solar cell, 30 Onboard battery, 11 First DC / DC converter, 12 Inverter, 13 Second DC / DC converter, 15 Control unit, 50 Power management system, 51 Processing unit, 511 Order acquisition unit, 512 Contract unit, 513 Notification unit, 514 Battery information acquisition unit, 515 Setting value change unit, 52 Memory unit, 53 Communication unit.

Claims

1. A power management system that manages the exchange of power between multiple distributed power systems connected to the same power transmission and distribution network, Each distributed power system has a power storage unit and a power conversion system. The power conversion system is controllable so that the power flow value between the distribution board to which the distributed power system and load are connected and the power transmission and distribution network becomes a set value. The aforementioned power management system is When power is exchanged between multiple distributed power systems via the aforementioned power transmission and distribution network, the system includes a notification unit that notifies the power conversion system on the transmission side of the set value of the power flow value on the transmission side and the power conversion system on the receiving side of the set value of the power flow value on the receiving side, so that the power discharged from the distribution board on the transmission side to the power transmission and distribution network matches the power drawn in by the distribution board on the receiving side to the power transmission and distribution network. Power management system.

2. At least one of the aforementioned distributed power systems includes a power generation device that converts renewable energy into electrical energy, The power conversion system controls the power flow value to the set value by performing at least one of the following: charge / discharge control of the energy storage unit, power generation suppression control of the power generation device, and power consumption control of the load. The power management system according to claim 1.

3. An information acquisition unit that acquires information about the energy storage unit notified by the power conversion system on the power transmission side when the remaining dischargeable capacity from the energy storage unit of the distributed power supply system on the power transmission side falls below a specified value, The system further includes a setting value changing unit that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit notifies the power conversion system on the power transmission side and the power conversion system on the power reception side of the changed setting value. The power management system according to claim 1 or 2.

4. An information acquisition unit that acquires information about the energy storage unit notified by the power conversion system on the receiving side when the available chargeable capacity of the energy storage unit of the distributed power supply system on the receiving side falls below a specified value, The system further includes a setting value changing unit that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit notifies the power transmission power conversion system and the power reception power conversion system of the changed setting value. The power management system according to claim 1 or 2.

5. An information acquisition unit that acquires information about the energy storage unit notified by the power conversion system on the power transmission side when the discharge power from the energy storage unit of the distributed power supply system on the power transmission side exceeds a specified value based on the discharge rated power, The system further includes a setting value changing unit that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit notifies the power transmission power conversion system and the power reception power conversion system of the changed setting value. The power management system according to claim 1 or 2.

6. An information acquisition unit that acquires information about the energy storage unit notified by the power conversion system on the receiving side when the charging power to the energy storage unit of the distributed power supply system on the receiving side exceeds a specified value based on the charging rated power, The system further includes a setting value changing unit that decreases the set value of the power flow value on the power transmission side and the set value of the power flow value on the power receiving side, in accordance with the acquired power storage unit information. The notification unit notifies the power transmission power conversion system and the power reception power conversion system of the changed setting value. The power management system according to claim 1 or 2.

7. A power conversion system included in a distributed power supply system having an energy storage unit, The distributed power supply system and the load are connected to a distribution board and a control unit capable of controlling the power flow value between the distribution network to a set value. The control unit, When exchanging power between multiple distributed power systems via the aforementioned power transmission and distribution network, the power management system notifies the power conversion system on the transmission side of the set value of the power flow value on the transmission side, and notifies the power conversion system on the receiving side of the set value of the power flow value on the receiving side, so that the power discharged from the distribution panel on the transmission side to the power transmission and distribution network matches the power drawn in from the distribution panel on the receiving side. The current value is controlled to become the acquired set value. Power conversion system.

8. The distributed power system includes a power generation device that converts renewable energy into electrical energy, The control unit performs at least one of the following: charge / discharge control of the energy storage unit, power generation suppression control of the power generation device, and power consumption control of the load, to control the power flow value so that it reaches the set value. The power conversion system according to claim 7.

9. The control unit, During the power exchange period in which power is being released to the aforementioned power transmission and distribution network, if the remaining dischargeable capacity from the energy storage unit falls below a specified value, the energy storage unit information is notified to the power management system. The modified power flow value setting is obtained from the aforementioned power management system. The power flow value is controlled to become the acquired modified setting value. The power conversion system according to claim 7 or 8.

10. The control unit, During the power exchange period in which power is being received from the aforementioned power transmission and distribution network, if the available capacity that can be charged in the energy storage unit falls below a specified value, the energy storage unit information is notified to the power management system. The modified power flow value setting is obtained from the aforementioned power management system. The power flow value is controlled to become the acquired modified setting value. The power conversion system according to claim 7 or 8.

11. The control unit, During the power exchange period in which power is being released to the aforementioned power transmission and distribution network, if the discharge power from the energy storage unit exceeds a specified value based on the discharge rated power, the energy storage unit information is notified to the power management system. The modified power flow value setting is obtained from the power management system. The power flow value is controlled to become the acquired modified setting value. The power conversion system according to claim 7 or 8.

12. The control unit, During the power exchange period in which power is received from the aforementioned power transmission and distribution network, if the power charged to the energy storage unit exceeds a specified value based on the charging rated power, the energy storage unit information is notified to the power management system. The modified power flow value setting is obtained from the aforementioned power management system. The power flow value is controlled to become the acquired modified setting value. The power conversion system according to claim 7 or 8.

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