Output control unit, power conversion device, power conversion system, battery residual amount management method and computer program

Abstract

To provide an output control unit, a power conversion device, a power conversion system, a battery residual amount management method and a computer program, which can avoid power generation loss without limiting power generation even when a control value for limiting power generation is set.SOLUTION: An output control unit is the output control unit which transmits a target battery residual amount being a target value of a battery residual amount of a storage battery at an end of a prescribed night charging period to a charging part which charges the storage battery by power generation by a power generation device and charges the storage battery by power supplied from a system in the night charging period. The unit includes a communication part for receiving a control value for controlling generated power from a first external device and a battery residual amount determination part for correcting the target battery residual amount and determining a new target battery residual amount. The communication part transmits the new target battery residual amount to the charging part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an output control unit, a power conversion device, a power conversion system, a battery remaining capacity management method, and a computer program. [Background technology]

[0002] The adoption of solar power generation equipment that can be connected to the power grid (hereinafter referred to as the grid) in ordinary households is expanding. When the power generated by a solar power generation equipment is greater than the power consumed by the load in the home, the surplus power is reverse-flowed to the grid and sold to the grid (hereinafter referred to as power selling). On sunny days, when the weather is favorable and solar power generation exceeds power consumption (demand), there is a concern that the amount of power sold will increase, making it impossible to maintain the grid frequency and voltage. To address this, power conditioners that connect solar power generation equipment to the grid are equipped with or have built-in output control devices that can reduce the power generated by the solar power generation equipment. The output control devices have a function to store a calendar of control values ​​(e.g., values ​​indicating the percentage of rated power to limit) that limit power generation in advance, anticipating days with high surplus power, and a function to connect to a computer server (hereinafter referred to as the server) of a general electricity transmission and distribution company and receive the control values. If the control value is set to 100%, power generation is not limited. For example, during periods such as Golden Week, the control value is set to a small value less than 100%. If the control value is set to a small value, the power generated by the photovoltaic power generation device is limited to a value smaller than the original power generation capacity, resulting in a power generation loss.

[0003] Patent Document 1 below discloses a solar power generation system to avoid this. This solar power generation system includes an electric water heater that boils water, and supplies generated power exceeding a control value to the electric water heater to perform boiling operation, thereby avoiding power generation loss. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-106937 Summary of the Invention [Problem to be solved by the invention]

[0005] Regarding Patent Document 1, there is a problem in that electric water heaters are not suitable as a load for adjusting power consumption. That is, when the hot water tank is full, the water cannot be heated any further, and surplus power cannot be absorbed (i.e., consumed). Furthermore, because the temperature of tap water fluctuates with the seasons, the adjustment function of an electric water heater also fluctuates with the seasons. For example, in the summer, when solar power generation is high and power generation restrictions are frequently required, the tap water temperature is high, making it more likely that the electric water heater will not be able to fully absorb (consume) the surplus power. Furthermore, if the water heater is left available for adjustment, there is a risk of running out of hot water, and there may be a sudden need to boil water during times when electricity rates are high, resulting in economic disadvantages.

[0006] Therefore, the present disclosure aims to provide an output control unit, a power conversion device, a power conversion system, a battery remaining capacity management method, and a computer program that can avoid power generation losses without limiting the power generation even when a control value that limits the power generation is set. [Means for solving the problem]

[0007] An output control unit according to one aspect of the present disclosure is an output control unit that charges a storage battery with power generated by a power generation device and transmits a target battery remaining capacity, which is a target value for the battery remaining capacity of the storage battery at the end of a predetermined night charging period, to a charging unit that charges the storage battery with power supplied from a grid during a predetermined night charging period.The output control unit includes: a communication unit that receives a control value for controlling the generated power from a first external device; and a battery remaining capacity determination unit that modifies the target battery remaining capacity and determines a new target battery remaining capacity according to the control value, and the communication unit transmits the new target battery remaining capacity to the charging unit. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide an output control unit, a power conversion device, a power conversion system, a battery remaining capacity management method, and a computer program that can avoid power generation losses without limiting the power generation even when a control value that limits the power generation is set. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a configuration of a power conversion system according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing the configuration of the output control unit shown in FIG. [Figure 3] FIG. 3 is a block diagram showing the configuration of the first server shown in FIG. [Figure 4] FIG. 4 is a block diagram showing the functional configuration of the output control unit. [Figure 5] FIG. 5 is a graph showing the relationship between the generated power and the control value. [Figure 6] FIG. 6 is a flowchart showing the operation of the output control unit. [Figure 7] FIG. 7 is a flowchart showing the operation of the second server. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Description of the embodiments of the present disclosure] The contents of the embodiments of the present disclosure will be listed and explained below. At least some of the embodiments described below may be combined in any combination.

[0011] (1) An output control unit according to a first aspect of the present disclosure charges a storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined overnight charging period, and transmits a target remaining battery level, which is a target value for the remaining battery level of the storage battery at the end of the overnight charging period, to a charging unit, which includes: a communication unit that receives a control value for controlling the generated power from a first external device; and a remaining battery level determination unit that modifies the target remaining battery level and determines a new target remaining battery level in accordance with the control value, and the communication unit transmits the new target remaining battery level to the charging unit. As a result, when a control value that limits the generated power is set, the storage battery can be charged with generated power that exceeds the control value, and power generation losses can be avoided without limiting the generated power.

[0012] (2) In the above (1), the target remaining battery capacity may be determined using the actual amount of power purchased from the grid and the actual amount of power sold to the grid in a system including a power generation device, a storage battery, and a charging unit. This allows the target remaining battery capacity to be appropriately determined, and therefore a new target remaining battery capacity to be appropriately determined.

[0013] (3) In the above (1) or (2), if the control value is less than a predetermined value, the battery remaining capacity determination unit may determine a new target battery remaining capacity by subtracting a predetermined correction amount from the target battery remaining capacity. This makes it possible to easily determine the new target battery remaining capacity.

[0014] (4) In the above (1) or (2), the battery remaining capacity determination unit may calculate a correction amount from the control value using a predetermined function, and may determine a new target battery remaining capacity by correcting the target battery remaining capacity using the correction amount. This makes it possible to easily determine an appropriate new target battery remaining capacity.

[0015] (5) In the above (1) or (2), the battery remaining capacity determination unit may determine a correction amount by machine learning using past control values ​​and actual amounts of power purchased from and sold to the grid in a system including a power generation device, a storage battery, and a charging unit, and may determine a new target battery remaining capacity by correcting the target battery remaining capacity using the correction amount. This allows a more appropriate new target battery remaining capacity to be determined.

[0016] (6) In the above (1) or (2), the battery remaining capacity determination unit may determine a correction amount based on a weather forecast for the location where the power generation device is installed and the actual amounts of sold and purchased power for past days on which the control value was a predetermined value indicating no limit on power generation, and may determine a new target battery remaining capacity by correcting the target battery remaining capacity based on the correction amount. This makes it easy to determine an appropriate new target battery remaining capacity.

[0017] (7) In the above (2), the communication unit may transmit the actual amount of purchased power and the actual amount of sold power to the second external device, and may receive the target remaining battery capacity from the second external device. This allows an appropriate target remaining battery capacity to be obtained from the second external device, and an appropriate new target remaining battery capacity to be determined.

[0018] (8) In the above (2), the battery remaining capacity determination unit may determine the target battery remaining capacity using the actual amount of power purchased and the actual amount of power sold. This allows the output control unit to determine an appropriate target battery remaining capacity and reduce the load without transmitting the actual amount of power purchased and the actual amount of power sold to an external device.

[0019] (9) A power conversion device according to a second aspect of the present disclosure includes a storage battery, a charging unit that charges the storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined overnight charging period, and an output control unit that transmits a target remaining battery level, which is a target value for the remaining battery level of the storage battery at the end of the overnight charging period, to the charging unit, wherein the output control unit receives a control value that controls the generated power from a first external device, modifies the target remaining battery level according to the control value to determine a new target remaining battery level, and transmits the new target remaining battery level to the charging unit. As a result, when a control value that limits the generated power is set, generated power that exceeds the control value can be charged to the storage battery, and power generation losses can be avoided without limiting the generated power.

[0020] (10) A power conversion system according to a third aspect of the present disclosure includes the power conversion device described in (9) above and a second external device that transmits a target battery remaining capacity to an output control unit. When a control value that limits power generation is set, power generation exceeding the control value can be charged to the storage battery, and power generation loss can be avoided without limiting the power generation.

[0021] (11) A battery remaining capacity management method according to a fourth aspect of the present disclosure is a battery remaining capacity management method in a system including a storage battery and a charging unit that charges the storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined overnight charging period, the method including the steps of receiving a control value for controlling the generated power from a first external device, correcting a target remaining battery capacity that is a target value for the remaining battery capacity of the storage battery at the end of the overnight charging period in accordance with the control value to determine a new target remaining battery capacity, and causing the charging unit to perform overnight charging based on the new target remaining battery capacity. As a result, when a control value that limits the generated power is set, generated power exceeding the control value can be charged to the storage battery, and power generation losses can be avoided without limiting the generated power.

[0022] (12) A computer program according to a fifth aspect of the present disclosure causes a computer controlling a system including a storage battery and a charging unit that charges the storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined overnight charging period to: receive a control value for controlling the generated power from a first external device; modify a target remaining battery level, which is a target value for the remaining battery level of the storage battery at the end of the overnight charging period, according to the control value, to determine a new target remaining battery level; and cause the charging unit to perform overnight charging based on the new target remaining battery level. As a result, when a control value that limits the generated power is set, the storage battery can be charged with generated power that exceeds the control value, thereby avoiding power generation losses without limiting the generated power.

[0023] [Details of the embodiments of the present disclosure] In the following embodiments, the same components are denoted by the same reference numerals, and their names and functions are also the same, so detailed descriptions thereof will not be repeated.

[0024] (System Configuration) 1, a power conversion system 100 according to an embodiment of the present disclosure includes a power conversion device 102, an output control unit 104, and a PV (Photovoltaic) panel 106, which is a solar panel. The power conversion system 100 is installed in, for example, a house. The power conversion device 102 and the PV panel 106 are disposed outdoors, and the output control unit 104 is disposed indoors. The output control unit 104 is, for example, a remote control. The output control unit 104 has a function of automatically determining the overnight charging amount of a storage battery 122 included in the power conversion device 102.

[0025] The power conversion device 102 includes a PCS (Power Conditioning System) 120 and a storage battery 122. The storage battery 122 is a chargeable and dischargeable storage battery such as a lithium-ion secondary battery. The storage battery 122 functions as a DC power supply. The PCS 120 includes a bidirectional DC / AC converter, and converts DC power output from the storage battery 122 when the storage battery 122 is discharged into AC power and outputs the AC power. The AC power output from the PCS 120 is supplied to a load 202. The PCS 120 also converts AC power supplied from the system power supply 200 via the watt-hour meter 110 into DC power and charges the storage battery 122. The PCS 120 also converts DC power generated by the PV panel 106 into AC power and outputs the AC power. As a result, the power generated by the PV panel 106 is supplied to the load 202.

[0026] The PCS 120 can sell surplus power remaining after subtracting power consumed by the load 202 from the power generated by the PV panel 106. The PCS 120 can also charge the storage battery 122 with the surplus power. The PCS 120 includes a DC / DC converter and converts the voltage of the DC power supplied from the PV panel 106 into a voltage suitable for charging the storage battery 122, thereby charging the storage battery 122. For example, during a time period when the purchase price of surplus power (i.e., the price per kWh when selling power) is relatively high, the PCS 120 sells as much surplus power as possible. During a time period when the purchase price of surplus power is relatively low, the PCS 120 charges the storage battery 122 with the surplus power, and when power consumption is greater than power generation, the shortfall is supplied by discharging the storage battery 122.

[0027] The PV panel 106 is a flat panel in which a plurality of solar battery cells connected in series are arranged and sealed using tempered glass or the like. The PV panel 106 functions as a DC power supply. As described above, DC power output from the PV panel 106 is supplied to the PCS 120, converted into AC power, and supplied to the load 202. Although one PV panel 106 is shown in FIG. 1, a plurality of PV panels 106 may be arranged. In this case, an input terminal may be provided in the PCS 120 corresponding to each of the plurality of PV panels 106.

[0028] The load 202 is supplied with AC power from the grid power supply 200 via the watt-hour meter 110. The watt-hour meter 110 measures the power supplied from the grid power supply 200 (i.e., purchased power) and the power output to the grid power supply 200 (i.e., sold power). The purchased power and sold power measured by the watt-hour meter 110 are input to, for example, the output control unit 104, and are aggregated (time-integrated) over a predetermined period to calculate the amount of purchased power and the amount of sold power, respectively. A distribution board (not shown) is disposed between the watt-hour meter 110 and the power conversion device 102 and the load 202. The distribution board includes a contract breaker, a ground fault circuit interrupter, etc.

[0029] The output control unit 104 is communicatively connected to the PCS 120 of the power conversion device 102, presents the status of the power conversion system 100 (e.g., the power generation status of the PV panel 106, the charging and discharging status of the storage battery 122, etc.) to a user, and accepts settings of operating conditions for the power conversion system 100 from the user. Referring to FIG. 2 , the output control unit 104 includes a control unit 130, a storage unit 132, a communication unit 134, a display unit 136, an operation unit 138, a timer 140, and a bus 142. Data exchange between the various units is performed via the bus 142. The control unit 130 is, for example, a CPU (Central Processing Unit). The storage unit 132 is, for example, a rewritable nonvolatile semiconductor memory, and stores a computer program (hereinafter simply referred to as a program) executed by the control unit 130. The control unit 130 also uses the storage unit 132 as a work memory for executing processes, and stores the results of the executed processes in the storage unit 132 as appropriate. The functions of the output control unit 104 are realized by the control unit 130 reading and executing a program stored in the storage unit 132 .

[0030] The communication unit 134 has a function of communicating with the watt-hour meter 110, the PCS 120, and the router 112. The communication between the communication unit 134 and the watt-hour meter 110 and the PCS 120 is, for example, wired communication, and the communication between the communication unit 134 and the router 112 is, for example, wireless communication. The router 112 connects the local network to a public network 216 such as the Internet. The router 112 is, for example, a wireless LAN (Local Area Network) router (e.g., a Wi-Fi router). This allows the output control unit 104 to communicate with a first server 210, a second server 212, and a third server 214, which are server computers, via the router 112 and the network 216.

[0031] The display unit 136 is a device for displaying information related to the power conversion system 100, and is, for example, a liquid crystal panel. The operation unit 138 is a device for inputting instructions to the output control unit 104, and is, for example, a touch panel. The display unit 136 and the operation unit 138 may be configured as an integrated device, for example, in which a touch panel is superimposed on a liquid crystal panel. In response to a request from the control unit 130, the timer 140 returns information indicating the current time (including the year, month, and day) (hereinafter simply referred to as the current time) to the control unit 130.

[0032] The first server 210 is a server provided by a general electricity transmission and distribution company with which a household in which the power conversion system 100 is installed has a contract. The first server 210 provides the power conversion system 100 with a control value that limits the power generation of the PV panel 106. Referring to FIG. 3 , the first server 210 includes a control unit 220, a storage unit 222, a communication unit 224, a timer 226, and a bus 228. The control unit 220 is, for example, a CPU, and realizes the functions of the first server 210 by controlling each unit of the first server 210. The storage unit 222 includes a rewritable semiconductor nonvolatile memory and a large-capacity storage device such as a hard disk drive. The storage unit 222 stores programs executed by the control unit 220. The communication unit 224 communicates with an external device (e.g., the router 112) via the network 216. Data received by the communication unit 224 is transmitted to and stored in the storage unit 222. The timer 226 receives a request from the control unit 220 and returns the current time to the control unit 220. Data exchange between each section is carried out via a bus 228 .

[0033] The control values ​​are provided as a schedule (hereinafter referred to as output control schedule) for, for example, one year or more. In the control schedule, control values ​​are set for each day, for example, in 30-minute increments. The output control unit 104 acquires (e.g., downloads) the output control schedule from the first server 210 and stores it in the storage unit 132. The output control schedule can be updated as appropriate. When the first server 210 updates the output control schedule, it transmits a notice to that effect to the output control unit 104, and the output control unit 104 acquires a new output control schedule from the first server 210. The output control schedule may include information indicating the timing to update the output control schedule, and the output control unit 104 may acquire a new output control schedule at a timing specified by the information included in the acquired output control schedule.

[0034] The second server 212 provides the output control unit 104 with a target remaining battery capacity, which is a target value for overnight charging of the storage battery 122. The configuration of the second server 212 is the same as the configuration of the first server 210 shown in FIG. 3. Therefore, the configuration of FIG. 3 will be referenced below as appropriate. The control unit 220 determines the target remaining battery capacity using weather forecast information (hereinafter simply referred to as weather forecast) provided by the third server 214, which will be described later. Note that multiple power conversion systems configured similarly to the power conversion system 100 are installed throughout the country. The second server 212 provides, for each output control unit included in each power conversion system, a target remaining battery capacity appropriate for that power conversion system.

[0035] The third server 214 is a server (not shown) that has the function of providing weather forecasts. The configuration of the third server 214 is the same as that of the first server 210 shown in FIG. 3. Therefore, the configuration of FIG. 3 will be referenced below as appropriate. The third server 214 maintains a weather forecast database and returns weather forecasts in response to external requests. The third server 214 is, for example, a server installed at the Japan Meteorological Agency, and publishes weather forecasts for each forecast region across Japan. Note that "publishing" means being ready to provide the latest weather forecast in response to an external weather forecast request. A "forecast region" refers, for example, to an area determined by dividing each prefecture into multiple regions. A "weather forecast" includes weather information for a specified period (e.g., three hours) from the time of announcement until the following day. Weather refers to the atmospheric condition, which is a combination of meteorological factors such as temperature, humidity, wind, cloud cover, visibility, rain, snow, and thunder. "Weather information" is expressed, for example, as one of five types: "clear," "cloudy," "rain," "rain or snow," and "snow." The power generated by the PV panel 106 depends on the weather, decreasing in the order of sunny, cloudy, rainy, rain or snowy, and snowy.

[0036] (Function of output control unit) 4 shows the functional configuration of the output control unit 104. The output control unit 104 includes a communication unit 250, a storage unit 252, a correction amount determination unit 254, and a target battery remaining capacity determination unit 256. The correction amount determination unit 254 and the target battery remaining capacity determination unit 256 function as a battery remaining capacity determination unit that determines the overnight charging amount of the storage battery 122. The communication unit 250 communicates with the watt-hour meter 110 and the PCS 120, and also communicates with the first server 210 and the second server 212 via the network 216. Specifically, the communication unit 250 receives the actual amounts of power sold and purchased in the power conversion system 100 from the watt-hour meter 110, and outputs the results to the storage unit 252 for storage. The communication unit 250 reads out the actual amounts of power sold and power purchased from the storage unit 252 at a predetermined timing and transmits them to the second server 212, and receives from the second server 212 the target remaining battery level for the next overnight charging of the storage battery 122. The communication unit 250 transmits the actual amounts of power sold and power purchased, for example, once a day. The communication unit 250 may transmit the actual amounts of power sold and power purchased multiple times a day without overlapping. The communication unit 250 also obtains an output control schedule from the first server 210 and outputs it to the storage unit 252 for storage. The communication unit 250 obtains the output control schedule at the timing described above. The communication unit 250 is realized by the communication unit 134 shown in FIG. 2.

[0037] The storage unit 252 stores data received from the communication unit 250 (actual amounts of power sold and purchased, target remaining battery capacity, and control schedule). The actual amounts of power sold and purchased are stored for a predetermined period. The target remaining battery capacity and control schedule only need to store the latest data, and may be overwritten with new data. The storage unit 252 is realized by the storage unit 132 shown in FIG. 2.

[0038] The correction amount determination unit 254 determines a correction amount for correcting the target remaining battery capacity. The target remaining battery capacity is set without considering whether or not there is a power generation limit on the PV panel 106. Therefore, if there is a power generation limit on the PV panel 106, the target remaining battery capacity is corrected by the correction amount. In other words, the correction amount is intended to reduce the target remaining battery capacity. By reducing the target remaining battery capacity, it is possible to ensure that the storage battery 122 after overnight charging has sufficient free capacity (amount of power) to be charged with surplus power generated by the PV panel 106 the next time. FIG. 5 shows an example of the power generated by the PV panel 106 and its limit value. In FIG. 5, the horizontal axis represents the time of day, and the vertical axis represents the ratio (%) of the power generation power to the maximum value. The solid line represents the change in the power generated by the PV panel 106, and the dashed line represents the limit value. The limit value limits the amount of power generated by the PV panel 106, as indicated by the diagonal lines. Therefore, if the storage battery 122 can be charged with the amount of power in the shaded area, the PV panel 106 does not need to limit power generation, and no power generation loss occurs.

[0039] The correction amount determination unit 254 reads out the control schedule from the storage unit 252 and determines the correction amount based on the control value for the next power generation period of the PV panel 106 (for example, the next day) included therein. The correction amount determination unit 254 outputs the determined correction amount to the target remaining battery capacity determination unit 256. If the control value is smaller than 100%, the correction amount determination unit 254 sets the correction amount to, for example, a predetermined value. The predetermined value is, for example, 10% or 20%. This makes it possible to easily determine a new target remaining battery capacity.

[0040] If the control value is smaller than 100%, the correction amount determination unit 254 may determine the correction amount according to the control value. The correction amount determination unit 254 may determine the correction amount from the control value using, for example, a predetermined function (such as a linear function or a quadratic function). In this way, an appropriate new target remaining battery capacity can be easily determined.

[0041] The correction amount determination unit 254 may read the actual amounts of power sold and purchased in addition to the control value from the storage unit 252, perform machine learning using the control value together with the past control value, and determine the correction amount using the learning result (model). This allows a more appropriate new target remaining battery capacity to be determined.

[0042] The correction amount determination unit 254 may also determine the correction amount based on a weather forecast for the location where the PV panel 106 is installed and the actual amounts of power sold and power purchased for past days on which the control value was a predetermined value (i.e., 100%) indicating that power generation is not limited. This makes it possible to easily determine an appropriate new target remaining battery capacity.

[0043] The target battery remaining capacity determination unit 256 reads the target battery remaining capacity from the storage unit 252 and corrects the target battery remaining capacity using the correction amount received from the correction amount determination unit 254 to determine a new target battery remaining capacity. Specifically, the target battery remaining capacity determination unit 256 subtracts the correction amount from the target battery remaining capacity read from the storage unit 252 to obtain a new target battery remaining capacity (hereinafter also referred to as corrected target battery remaining capacity). The target battery remaining capacity determination unit 256 outputs the corrected target battery remaining capacity to the communication unit 250. In response to this, the communication unit 250 transmits the corrected target battery remaining capacity to the PCS 120. As a result, the PCS 120 performs overnight charging using the corrected target battery remaining capacity the next time overnight charging is performed. In other words, the PCS 120 charges the storage battery 122 with nighttime power from the grid power source 200 so that the battery remaining capacity of the storage battery 122 becomes the corrected target battery remaining capacity at the end of overnight charging. As a result, when a control value that limits the power generation of the PV panel 106 is set, the power generation exceeding the control value can be charged into the storage battery 122. Therefore, the power generation of the PV panel 106 is not limited, and the occurrence of power generation loss can be avoided.

[0044] (Output control unit operation) The operation of the output control unit 104 will be described in detail with reference to Fig. 6. The process shown in Fig. 6 is started, for example, when the output control unit 104 is operated by a user to enable a function for automatically determining the overnight charging amount, and the control unit 130 reads and executes a predetermined program stored in the storage unit 132. In parallel with this program, the control unit 130 executes a program for calculating the amount of purchased power and the amount of sold power. For example, the control unit 130 calculates the amount of purchased power and the amount of sold power for a period excluding the overnight charging period (for example, from 6:00 to 22:00) using the purchased power and sold power input from the energy meter 110. The control unit 130 stores the calculated amount of purchased power and the amount of sold power in the storage unit 132.

[0045] In step 300, the control unit 130 determines whether to download the control values. If it is determined that the control values ​​should be downloaded, control proceeds to step 302. Otherwise, control proceeds to step 304. When step 300 is executed for the first time, the control unit 130 determines that the control values ​​should be downloaded. For example, when step 300 is executed for the second or subsequent time, the control unit 130 determines whether the update timing (including date information) included in the output control schedule that has already been downloaded and stored in the storage unit 132 has arrived. That is, the control unit 130 obtains the current time from the timer 140 and determines whether the update timing has passed. If the update timing has passed, it is determined that the control values ​​should be downloaded; otherwise, it is determined that the control values ​​should not be downloaded. Furthermore, when the first server 210 updates the output control schedule and transmits predetermined information (hereinafter referred to as an update notification) to the output control unit 104, the control unit 130 determines that the control values ​​should be downloaded upon receiving the update notification from the first server 210.

[0046] In step 302 , the control unit 130 accesses the first server 210 , downloads the output control schedule, and stores the data in the storage unit 132 .

[0047] In step 304, the control unit 130 determines whether or not to transmit the actual amounts of power sold and purchased in the power conversion system 100. Specifically, the control unit 130 determines whether or not it is time to transmit the actual amounts of power (hereinafter referred to as the actual amount transmission time). The actual amount transmission time is set in advance and stored in the storage unit 132. For example, one or more predetermined times in a day are set as the actual amount transmission time. If it is determined that the actual amount should be transmitted, control proceeds to step 306. Otherwise, control proceeds to step 308.

[0048] In step 306, the control unit 130 transmits the amount of power sold and the amount of power purchased in the power conversion system 100 to the second server 212. Specifically, the control unit 130 reads from the storage unit 132 the amount of power sold and the amount of power purchased that were stored in the storage unit 132 after the previous transmission, among the amounts of power sold and the amounts of power purchased stored in the storage unit 132, and transmits the amount of power sold and the amount of power purchased to the second server 212 together with information indicating the time (including the year, month, and day) at which they were calculated. The transmitted data is accompanied by information identifying the output control unit 104 (hereinafter referred to as identification information). The MAC address of the communication unit 134 of the output control unit 104 may be used as the identification information of the output control unit 104. As described below, the second server 212 stores the received data (the amount of power sold and the amount of power purchased, and the time at which they were calculated) in association with the identification information of the output control unit 104. The second server 212 uses the received data to calculate the target remaining battery level for overnight charging in the power conversion system 100.

[0049] In step 308, the control unit 130 determines whether or not a target remaining battery capacity has been received from the second server 212. If it is determined that the target remaining battery capacity has been received, control proceeds to step 310. Otherwise, control proceeds to step 312. The target remaining battery capacity represents the remaining battery capacity of the storage battery 122 at the end of overnight charging.

[0050] In step 310, the control unit 130 stores the data (target remaining battery power) received in step 308 in the storage unit 132. Thereafter, the control proceeds to step 312.

[0051] In step 312, the control unit 130 determines whether or not to prepare for overnight charging. If it is determined that preparation is to be made, control proceeds to step 314. If not, control returns to 300. Specifically, the control unit 130 obtains the current time from the timer 140 and determines whether a predetermined time (hereinafter referred to as the preparation time) has arrived. The preparation time is set in advance and stored in the memory unit 132. A time before the start time of overnight charging is set as the preparation time. For example, if the overnight charging period is between 10:00 PM and 6:00 AM the following day, the preparation time is set to, for example, 9:00 PM. Note that step 312 is executed repeatedly, but after a YES determination is made once a day and preparation for charging is made, a NO determination is made even if the preparation time has passed.

[0052] In step 314, the control unit 130 determines whether to limit the power generation of the PV panel 106. If it is determined that the power generation should be limited, control proceeds to step 316. If not, control proceeds to step 318. Specifically, the control unit 130 reads the control value for the first photovoltaic power generation period after the current time from the output control schedule stored in the memory unit 132, and determines whether the read value includes a value less than 100%. If it includes a value less than 100%, it is determined that the power generation should be limited. Otherwise, it is determined that the power generation should not be limited. The photovoltaic power generation period refers to the daytime period when sunlight is expected (e.g., from 6:00 to 18:00), and power generation by the PV panel 106 can occur during this period.

[0053] In step 316, control unit 130 corrects the target remaining battery capacity stored in memory unit 132 in step 310. Specifically, control unit 130 executes the processes described as the functions of correction amount determination unit 254 and target remaining battery capacity determination unit 256 shown in FIG. 4, determines a new target remaining battery capacity corrected by the correction amount (i.e., corrected target remaining battery capacity), and stores it in memory unit 132. Control unit 130, for example, overwrites the target remaining battery capacity stored in memory unit 132 with the corrected target remaining battery capacity. Thereafter, control proceeds to step 318.

[0054] In step 318, control unit 130 reads the target remaining battery capacity from storage unit 132 and transmits it to PCS 120. If step 312 is executed, the transmitted target remaining battery capacity is the corrected target remaining battery capacity, and if step 312 is not executed, it is the target remaining battery capacity stored in storage unit 132 in step 310. Control then proceeds to step 320. Having received the target remaining battery capacity, PCS 120 creates a schedule for charging an amount of power equal to the difference between the remaining battery capacity of storage battery 122 at the start of the overnight charging period and the target remaining battery capacity, so that the remaining battery capacity of storage battery 122 will become the target remaining battery capacity at the end of the overnight charging period. PCS 120 charges storage battery 122 using nighttime power from grid power source 200 according to the created schedule.

[0055] In step 320, the control unit 130 determines whether an instruction to end the program has been received. If it is determined that an instruction to end the program has been received, the program ends. If not, control returns to step 300, and the above-described processing is repeated. The instruction to end the program is issued, for example, by the user operating the operation unit 138 of the output control unit 104 to disable the function that automatically determines the overnight charging amount.

[0056] (Operation of the second server) The operation of the second server 212 will be described with reference to Fig. 7. The processing shown in Fig. 7 is realized by the control unit 220 of the second server 212 reading and executing a program stored in the storage unit 222. As described above, a plurality of power conversion systems configured similarly to the power conversion system 100 are installed throughout the country, and the second server 212 provides them with a target remaining battery capacity. In the following, the description of the power conversion system 100 (including the output control unit 104) also applies to each of the plurality of power storage systems installed throughout the country.

[0057] In step 400, control unit 220 determines whether it is time to obtain a weather forecast (hereinafter referred to as weather forecast obtaining time). Specifically, control unit 220 obtains the current time from timer 226 and determines whether the current time has passed 5:00, 11:00, or 17:00. If it is determined that the weather forecast obtaining time has passed, control proceeds to step 402. If not, control proceeds to step 404.

[0058] In step 402, the control unit 220 acquires the nationwide weather forecast published by the third server 214. Specifically, the control unit 220 accesses the third server 214 and downloads the weather forecast. The control unit 220 stores the acquired weather forecast in the storage unit 222. Thereafter, control proceeds to step 404. Note that the weather forecast is acquired only once a day after any of 5:00, 11:00, and 17:00.

[0059] In step 404, the control unit 220 determines whether or not the actual amount of power has been received via the communication unit 224. If it is determined that the actual amount of power has been received, control proceeds to step 406. Otherwise, control proceeds to step 408. The amount of power received by the control unit 220 is the actual amount of power sold and the amount of power purchased transmitted by the output control unit 104 in step 306 shown in FIG.

[0060] In step 406, the control unit 220 stores the data received in step 404 in the storage unit 222. Thereafter, control proceeds to step 408. Specifically, the control unit 220 stores the received actual amounts of sold and purchased power (including calculation time information) in the storage unit 222 in association with the specific information attached thereto.

[0061] In step 408, the control unit 220 determines whether or not to transmit the target remaining battery capacity. If it is determined that the target remaining battery capacity should be transmitted, control proceeds to step 410. Otherwise, control proceeds to step 412. Specifically, the control unit 220 obtains the current time from the timer 226, and determines whether or not the current time has passed a predetermined time (hereinafter referred to as the target remaining battery capacity transmission time). The target remaining battery capacity transmission time is stored in advance in the storage unit 222. The target remaining battery capacity transmission time is set to a time that is earlier than the preparation time (see step 312 shown in FIG. 6) when the output control unit 104 prepares for overnight charging.

[0062] In step 410, the control unit 220 calculates a target remaining battery capacity and transmits it to the output control unit 104. Then, control proceeds to step 412. Specifically, the control unit 220 calculates an appropriate target remaining battery capacity for the storage battery 122, assuming that the power conversion system 100 operates in the green mode. In the green mode, the power charged to the storage battery 122 by overnight charging is an auxiliary operation from an economical viewpoint. That is, the highest priority is given to surplus power generated by the PV panel 106. The next priority is given to relatively inexpensive power (e.g., nighttime power) supplied from the grid power source 200 by each time period. Finally, the last priority is given to relatively expensive power supplied from the grid power source 200 by each time period. The appropriate amount of charging of the storage battery 122 by overnight charging depends on the tendency of power generation by the PV panel 106, the tendency of power consumption in the home where the power conversion system 100 is installed, the weather in the location where the PV panel 106 is installed, and the like. The trends in power generation by the PV panel 106 and trends in household power consumption can be obtained from the past amounts of power sold and purchased in the power conversion system 100. Therefore, the control unit 220 performs machine learning using, for example, the past amounts of power sold and purchased that are stored in the memory unit 222 in association with the specific information of the output control unit 104, and past weather forecasts. The control unit 220 then determines the target remaining battery capacity using the learning results and the weather forecast for the first daytime after overnight charging of the storage battery 122.

[0063] The target remaining battery level transmitted in step 410 is received by the output control unit 104. As described above, if output limitation of the PV panel 106 is scheduled, the output control unit 104 modifies the target remaining battery level received from the second server 212 and determines a new target remaining battery level (corrected target remaining battery level) (see step 316 shown in FIG. 6 ). The PCS 120 performs overnight charging using the corrected target remaining battery level received from the output control unit 104. If output limitation of the PV panel 106 is not scheduled, the PCS 120 performs overnight charging using the target remaining battery level received from the output control unit 104.

[0064] In step 412, the control unit 220 determines whether an instruction to terminate has been received. The instruction to terminate is given, for example, by the administrator operating an operating device (computer keyboard, mouse, etc.) of the second server 212. If it is determined that an instruction to terminate has been received, the program terminates. If not, control returns to step 400, and the above processing is repeated.

[0065] As described above, when a control value that limits the power generation of the PV panel 106 is set (i.e., when the control value is a value smaller than 100%), it is possible to ensure in advance that the storage battery 122 has available capacity to be charged with the expected surplus power of the PV panel 106, and it is possible to charge the storage battery 122 with power generation that exceeds the control value. Therefore, it is possible to avoid power generation losses without limiting the power generation of the PV panel 106.

[0066] The second server 212 determines the target remaining battery capacity using the actual amount of power purchased from the grid power supply 200 and the actual amount of power sold to the grid power supply 200 in the power conversion system 100 including the PV panel 106, the storage battery 122, and the PCS 120. This makes it possible to appropriately determine the target remaining battery capacity, and therefore to appropriately determine a new target remaining battery capacity.

[0067] As described above, if the control value is less than the predetermined value (i.e., 100%), the output control unit 104 determines a new target remaining battery capacity by subtracting a predetermined correction amount from the target remaining battery capacity. This makes it easy to determine a new target remaining battery capacity.

[0068] As described above, the output control unit 104 may calculate a correction amount from the control value using a predetermined function, and may determine a new target remaining battery capacity by correcting the target remaining battery capacity using the correction amount. This makes it possible to easily determine an appropriate new target remaining battery capacity.

[0069] As described above, the output control unit 104 may determine the correction amount by machine learning using the past control values ​​and the actual amounts of power purchased from and sold to the grid power source 200 in the power conversion system 100 including the PV panel 106, the storage battery 122, and the PCS 120. Then, the output control unit 104 may determine a new target remaining battery amount by correcting the target remaining battery amount using the correction amount. This makes it possible to determine a more appropriate new target remaining battery amount.

[0070] As described above, the output control unit 104 may determine the correction amount based on the weather forecast for the location where the PV panel 106 is installed and the actual amounts of power sold and power purchased for past days on which the control value was a predetermined value (i.e., 100%) indicating that power generation is not limited. The output control unit 104 may then determine a new target remaining battery capacity by modifying the target remaining battery capacity using the correction amount. This makes it easy to determine an appropriate new target remaining battery capacity.

[0071] As described above, the communication unit 134 of the output control unit 104 transmits the actual amount of power purchased and the actual amount of power sold to the second server 212, and receives the target remaining battery capacity from the second server 212. This makes it possible to obtain an appropriate target remaining battery capacity from the second server 212, and to determine an appropriate new target remaining battery capacity.

[0072] In the above, the case where the second server 212 transmits the target remaining battery amount to the output control unit 104 at a predetermined timing (i.e., the target remaining battery amount transmission time) has been described, but this is not limiting. For example, the output control unit 104 may request the second server 212 to transmit the target remaining battery amount at a predetermined timing, and the second server 212 may transmit the target remaining battery amount to the output control unit 104 in response.

[0073] Furthermore, the output control unit 104 may obtain weather forecast information for the area where the power conversion system 100 is installed from the second server 212. The output control unit 104 may determine the target remaining battery capacity using the weather forecast information and the actual amounts of power sold and purchased by the power conversion system 100. This allows an appropriate target remaining battery capacity to be determined, and an appropriate new target remaining battery capacity to be determined. The output control unit 104 does not need to transmit the actual amounts of power sold and purchased by the power conversion system 100 to the second server 212, thereby reducing the load.

[0074] In the above description, the power conversion device 102 is a hybrid type that converts the power generated by the PV panel 106 and the charging / discharging power of the storage battery 122. However, this is not limiting. The power conversion device 102 may be a single-function power conversion device that does not have the function of converting the power generated by the PV panel 106. In this case, a photovoltaic power generation device having a power conditioner and a single-function power conversion device having a power conditioner that controls the charging / discharging of the storage battery are installed side by side to form a power conversion system. Furthermore, the PCS 120 and the storage battery 122 are not limited to being integrally formed. The PCS 120 and the storage battery 122 may be separate. In these cases, the output control unit 104 may determine a corrected target remaining battery capacity and transmit it to the power conditioner of the single-function power conversion device, as described above.

[0075] In the above description, the output control unit 104 is disposed outside the power conversion device 102, but the present invention is not limited to this. The output control unit 104 may be included inside the power conversion device 102. In this case, the PCS may be configured to realize the functions of the output control unit 104.

[0076] In the above, the case where the target remaining battery capacity is corrected when charging the stationary storage battery 122 at night has been described, but the present invention is not limited to this. Instead of or in addition to the storage battery 122, the target remaining battery capacity for overnight charging may be corrected for a storage battery mounted on an electric vehicle. This allows the storage battery mounted on the electric vehicle to be charged with surplus power when power generation is limited. This makes it possible to avoid power generation losses.

[0077] Although the above describes a case where the power conversion system 100 includes the PV panel 106, the present invention is not limited to this. If the power conversion system includes a power generation device that is affected by weather, the target remaining battery level for overnight charging of the storage battery can be corrected in the same manner as above, according to the power generation limit value of the power generation device.

[0078] Although the present disclosure has been described above by explaining the embodiments, the above-described embodiments are merely examples, and the present disclosure is not limited to only the above-described embodiments. The scope of the present disclosure is defined by the claims in the claims, taking into consideration the description of the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wordings described therein. [Explanation of symbols]

[0079] 100 Power Conversion System 102 Power conversion device 104 Output Control Unit 106 PV panels 110 Energy meter 112 Router 120 PCS 122 Storage battery 130, 220 control unit 132, 222, 252 storage section 134, 224, 250 Communications Department 136 Display section 138 Operation section 140, 226 Timer Buses 142 and 228 200 Grid power supply 202 Load 210 First Server 212 Second Server 214 Third Server 216 Network 254 Correction amount determination unit 256 Target battery remaining capacity determination unit

Claims

1. an output control unit that charges a storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined overnight charging period, and transmits a target remaining battery amount that is a target value of the remaining battery amount of the storage battery at the end of the overnight charging period to a charging unit, a communication unit that receives a control value for controlling the generated power from a first external device; a battery remaining capacity determination unit that determines a new target battery remaining capacity by modifying the target battery remaining capacity in accordance with the control value; The communication unit transmits the new target remaining battery capacity to the charging unit.

2. 2. The output control unit according to claim 1, wherein the target battery remaining capacity is determined using an actual amount of power purchased from the grid and an actual amount of power sold to the grid in a system including the power generation device, the storage battery, and the charging unit.

3. 3. The output control unit according to claim 1, wherein if the control value is less than a predetermined value, the remaining battery capacity determination unit determines the new target remaining battery capacity by subtracting a predetermined correction amount from the target remaining battery capacity.

4. The battery remaining capacity determination unit calculating a correction amount from the control value using a predetermined function; 3. The output control unit according to claim 1, wherein the target remaining battery capacity is corrected by the correction amount to determine the new target remaining battery capacity.

5. The battery remaining capacity determination unit determining a correction amount by machine learning using a record of the amount of power purchased from the grid and a record of the amount of power sold to the grid in a system including the power generation device, the storage battery, and the charging unit, and the past control value; 3. The output control unit according to claim 1, wherein the target remaining battery capacity is corrected by the correction amount to determine the new target remaining battery capacity.

6. The battery remaining capacity determination unit determining a correction amount based on a weather forecast for a location where the power generation device is installed and the actual amount of power sold and the actual amount of power purchased for a day corresponding to the weather forecast among past days on which the control value was a predetermined value indicating that the power generation power is not limited; 3. The output control unit according to claim 1, wherein the target remaining battery capacity is corrected by the correction amount to determine the new target remaining battery capacity.

7. The communication unit Transmitting the actual amount of purchased power and the actual amount of sold power to a second external device; The output control unit of claim 2 , further comprising: a second external device configured to receive the target battery level from the second external device.

8. The output control unit according to claim 2 , wherein the battery remaining capacity determination unit determines the target battery remaining capacity using an actual record of the purchased power amount and an actual record of the sold power amount.

9. A storage battery and a charging unit that charges the storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined overnight charging period; an output control unit that transmits a target remaining battery capacity, which is a target value of the remaining battery capacity of the storage battery at an end of the overnight charging period, to the charging unit; The output control unit receiving a control value for controlling the generated power from a first external device; modifying the target remaining battery capacity in accordance with the control value to determine a new target remaining battery capacity; The power conversion device transmits the new target remaining battery capacity to the charging unit.

10. The power conversion device according to claim 9 ; a second external device that transmits the target remaining battery capacity to the output control unit.

11. A battery remaining capacity management method in a system including a storage battery and a charging unit that charges the storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined nighttime charging period, receiving a control value for controlling the generated power from a first external device; a step of correcting a target remaining battery amount, which is a target value of the remaining battery amount of the storage battery at the end of the overnight charging period, in accordance with the control value, and determining a new target remaining battery amount; causing the charging unit to perform overnight charging based on the new target remaining battery capacity.

12. a computer that controls a system including a storage battery and a charging unit that charges the storage battery with power generated by a power generation device and charges the storage battery with power supplied from a grid during a predetermined nighttime charging period; a function of receiving a control value for controlling the generated power from a first external device; a function of correcting a target remaining battery amount, which is a target value of the remaining battery amount of the storage battery at the end of the overnight charging period, according to the control value, and determining a new target remaining battery amount; and causing the charging unit to perform overnight charging based on the new target remaining battery capacity.

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